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Introducing smart-imaging into radiologists’ daily practice.

Author and Curator: Dror Nir, PhD

Radiology congresses are all about imaging in medicine. Interestingly, radiology originates from radiation. It was the discovery of X-ray radiation at the beginning of the 20th century that opened the road to “seeing” the inside of the human body without harming it (at that time that meant cutting into the body).

Radiology meetings are about sharing experience and knowhow on imaging-based management patients. The main topic is always image-interpretation: the bottom line of clinical radiology! This year’s European Congress of Radiology (ECR) dedicated few of its sessions to recent developments in image-interpretation tools. I chose to discuss the one that I consider contributing the most to the future of cancer patients’ management.

In the refresher course dedicated to computer application the discussion was aimed at understanding the question “How do image processing and CAD impact radiological daily practice?” Experts’ reviews gave the audience some background information on the following subjects:

  1. A.     The link between image reconstruction and image analysis.
  2. B.     Semantic web technologies for sharing and reusing imaging-related information
  3. C.     Image processing and CAD: workflow in clinical practice.

I find item A to be a fundamental education item. Not once did I hear a radiologist saying: “I know this is the lesion because it’s different on the image”.  Being aware of the computational concepts behind image rendering, even if it is at a very high level and lacking deep understanding of the computational processes,  will contribute to more balanced interpretations.

Item B is addressing the dream of investigators worldwide. Imagine that we could perform a web search and find educating, curated materials linking visuals and related clinical information, including standardized pathology reporting. We would only need to remember that search engines used certain search methods and agree, worldwide, on the method and language to be used when describing things. Having such tools is a pre-requisite to successful pharmaceutical and bio-tech development.

I find item C strongly linked to A, as all methods for better image interpretation must fit into a workflow. This is a design goal that is not trivial to achieve. To understand what I mean by that, try to think about how you could integrate the following examples in your daily workflow: i.e. what kind of expertise is needed for execution, how much time it will take, do you have the infrastructure?

In the rest of this post, I would like to highlight, through examples that were discussed during ECR 2012, the aspect of improving cancer patients’ clinical assessment by using information fusion to support better image interpretation.

  • Adding up quantitative information from MR spectroscopy (quantifies biochemical property of a target lesion) and Dynamic Contrast Enhanced MR imaging (highlights lesion vasculature).

Image provided by: Dr. Pascal Baltzer, director of mammography at the centre for radiology at Friedrich Schiller University in Jena, Germany

 
  • Registration of images generated by different imaging modalities (Multi-modal imaging registration).

The following examples: Fig 2 demonstrates registration of a mammography image of a breast lesion to an MRI image of this lesion. Fig3 demonstrates registration of an ultrasound image of a breast lesion scanned by an Automatic Breast Ultrasound (ABUS) system and an MRI image of the same lesion.

Images provided by members of the HAMAM project (an EU, FP7 funded research project: Highly Accurate Breast Cancer Diagnosis through Integration of Biological Knowledge, Novel Imaging Modalities, and Modelling): http://www.hamam-project.org

 

 Multi-modality image registration is usually based on the alignment of image-features apparent in the scanned regions. For ABUS-MRI matching these were: the location of the nipple and the breast thickness; the posterior of the nipple in both modalities; the medial-lateral distance of the nipple to the breast edge on ultrasound; and an approximation of the rib­cage using a cylinder on the MRI. A mean accuracy of 14mm was achieved.

Also from the HAMAM project, registration of ABUS image to a mammography image:

registration of ABUS image to a mammography image, Image provided by members of the HAMAM project (an EU, FP7 funded research project: Highly Accurate Breast Cancer Diagnosis through Integration of Biological Knowledge, Novel Imaging Modalities, and Modelling): http://www.hamam-project.org

  • Automatic segmentation of suspicious regions of interest seen in breast MRI images

Segmentation of suspicious the lesions on the image is the preliminary step in tumor evaluation; e.g. finding its size and location. Since lesions have different signal/image character­istics to the rest of the breast tissue, it gives hope for the development of computerized segmentation techniques. If successful, such techniques bear the promise of enhancing standardization in the reporting of lesions size and location: Very important information for the success of the treatment step.

Roberta Fusco of the National Cancer Institute of Naples Pascal Foundation, Naples/IT suggested the following automatic method for suspi­cious ROI selection within the breast using dynamic-derived information from DCE-MRI data.

 

Automatic segmentation of suspicious ROI in breast MRI images, image provided by Roberta Fusco of the National Cancer Institute of Naples Pascal Foundation, Naples/IT

 

 Her algorithm includes three steps (Figure 2): (i) breast mask extraction by means of automatic intensity threshold estimation (Otsu Thresh-holding) on the par­ametric map obtained through the sum of intensity differences (SOD) calculated pixel by pixel; (ii) hole-filling and leakage repair by means of morphological operators: closing is required to fill the holes on the boundaries of breast mask, filling is required to fill the holes within the breasts, erosion is required to reduce the dilation obtained by the closing operation; (iii) suspicious ROIs extraction: a pixel is assigned to a suspicious ROI if it satisfies two conditions: the maximum of its normalized time-intensity curve should be greater than 0.3 and the maximum signal intensity should be reached before the end of the scan time. The first condition assures that the pixels within the ROI have a significant contrast agent uptake (thus excluding type I and type II curves) and the second condition is required for the time-intensity pattern to be of type IV or V (thus excluding type III curves).

Written by: Dror Nir, PhD

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Imaging: seeing or imagining? (Part 2)

Author and Curator: Dror Nir, PhD

This post is a continuation of

Imaging: seeing or imagining? (Part 1)

http://pharmaceuticalintelligence.com/2012/09/10/imaging-seeing-or-imagining-part-1/

That is the question…

Anyone who follows healthcare news, as I do , cannot help being impressed with the number of scientific and non-scientific items that mention the applicability of Magnetic Resonance Imaging (‘MRI’) to medical procedures.

A very important aspect that is worthwhile noting is that the promise MRI bears to improve patients’ screening – pre-clinical diagnosis, better treatment choice, treatment guidance and outcome follow-up – is based on new techniques that enables MRI-based tissue characterisation.

Magnetic resonance imaging (MRI) is an imaging device that relies on the well-known physical phenomena named “Nuclear Magnetic Resonance”. It so happens that, due to its short relaxation time, the 1H isotope (spin ½ nucleus) has a very distinctive response to changes in the surrounding magnetic field. This serves MRI imaging of the human body well as, basically, we are 90% water. The MRI device makes use of strong magnetic fields changing at radio frequency to produce cross-sectional images of organs and internal structures in the body. Because the signal detected by an MRI machine varies depending on the water content and local magnetic properties of a particular area of the body, different tissues or substances can be distinguished from one another in the scan’s resulting image.

MRI scan of a breast lesion (Source Radiology.com)

The main advantages of MRI in comparison to X-ray-based devices such as CT scanners and mammography systems are that the energy it uses is non-ionizing and it can differentiate soft tissues very well based on differences in their water content.

In the last decade, the basic imaging capabilities of MRI have been augmented for the purpose of cancer patient management, by using magnetically active materials (called contrast agents) and adding functional measurements such as tissue temperature to show internal structures or abnormalities more clearly.

In order to increase the specificity and sensitivity of MRI imaging in cancer detection, various imaging strategies have been developed. The most discussed in MRI related literature are:

  • T2 weighted imaging: The measured response of the 1H isotope in a resolution cell of a T2-weighted image is related to the extent of random tumbling and the rotational motion of the water molecules within that resolution cell. The faster the rotation of the water molecule, the higher the measured value of the T2 weighted response in that resolution cell. For example, prostate cancer is characterized by a low T2 response relative to the values typical to normal prostatic tissue [5].

T2 MRI pelvis with Endo Rectal Coil ( DATA of Dr. Lance Mynders, MAYO Clinic)

  • Dynamic Contrast Enhanced (DCE) MRI involves a series of rapid MRI scans in the presence of a contrast agent. In the case of scanning the prostate, the most commonly used material is gadolinium [4].

Axial MRI Lava DCE with Endo Rectal ( DATA of Dr. Lance Mynders, MAYO Clinic)

  • Diffusion weighted (DW) imaging: Provides an image intensity that is related to the microscopic motion of water molecules [5].

DW image of the left parietal glioblastoma multiforme (WHO grade IV) in a 59-year-old woman, Al-Okaili R N et al. Radiographics 2006;26:S173-S189

  • Multifunctional MRI: MRI image overlaid with combined information from T2-weighted scans, dynamic contrast-enhancement (DCE), and diffusion weighting (DW) [5].
  • Blood oxygen level-dependent (BOLD) MRI: Assessing tissue oxygenation. Tumors are characterized by a higher density of micro blood vessels. The images that are acquired follow changes in the concentration of paramagnetic deoxyhaemoglobin [5].

In the last couple of years, medical opinion leaders are offering to use MRI to solve almost every weakness of the cancer patients’ pathway. Such proposals are not always supported by any evidence of feasibility. For example, a couple of weeks ago, the British Medical Journal published a study [1] concluding that women carrying a mutation in the BRCA1 or BRCA2 genes who have undergone a mammogram or chest x-ray before the age of 30 are more likely to develop breast cancer than those who carry the gene mutation but who have not been exposed to mammography. What is published over the internet and media to patients and lay medical practitioners is: “The results of this study support the use of non-ionising radiation imaging techniques (such as magnetic resonance imaging) as the main tool for surveillance in young women with BRCA1/2 mutations.”.

Why is ultrasound not mentioned as a potential “non-ionising radiation imaging technique”?

Another illustration is the following advert:

Advert in favour of MRI termal imaging of breast

An MRI scan takes between 30 to 45 minutes to perform (not including the time of waiting for the interpretation by the radiologist). It requires the support of around 4 well-trained team members. It costs between $400 and $3500 (depending on the scan).

The important question, therefore, is: Are there, in the USA, enough MRI  systems to meet the demand of 40 million scans a year addressing women with radiographically dense  breasts? Toda there are approximately 10,000 MRI systems in the USA. Only a small percentage (~2%) of the examinations are related to breast cancer. A

A rough calculation reveals that around 10,000 additional MRI centers would need to be financed and operated to meet that demand alone.

References

  1. Exposure to diagnostic radiation and risk of breast cancer among carriers of BRCA1/2 mutations: retrospective cohort study (GENE-RAD-RISK), BMJ 2012; 345 doi: 10.1136/bmj.e5660 (Published 6 September 2012), Cite this as: BMJ 2012;345:e5660 – http://www.bmj.com/content/345/bmj.e5660
  1. http://www.auntminnieeurope.com/index.aspx?sec=sup&sub=wom&pag=dis&itemId=607075
  1. Ahmed HU, Kirkham A, Arya M, Illing R, Freeman A, Allen C, Emberton M. Is it time to consider a role for MRI before prostate biopsy? Nat Rev Clin Oncol. 2009;6(4):197-206.
  1. Puech P, Potiron E, Lemaitre L, Leroy X, Haber GP, Crouzet S, Kamoi K, Villers A. Dynamic contrast-enhanced-magnetic resonance imaging evaluation of intraprostatic prostate cancer: correlation with radical prostatectomy specimens. Urology. 2009;74(5):1094-9.
  1. Advanced MR Imaging Techniques in the Diagnosis of Intraaxial Brain Tumors in Adults, Al-Okaili R N et al. Radiographics 2006;26:S173-S189 ,

http://radiographics.rsna.org/content/26/suppl_1/S173.full

  1. Ahmed HU. The Index Lesion and the Origin of Prostate Cancer. N Engl J Med. 2009 Oct; 361(17): 1704-6

Writer: Dror Nir, PhD.

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Author and Curator: Dror Nir, PhD

 

As an entrepreneur who is promoting innovations in medical imaging I often find myself confronted with this question. Usually the issue is raised by a project’s potential financier by the way of the following remarks:

  • The Genome Project opens the road to “Star Track” kind of medicine. No one will need imaging.
  • What about development of new disease-specific markers? Would that put imaging out of business?
  • Soon we will have a way to “fix” bad cells’ DNA.  and so we will have no use for screening

In these situations I always find myself struggling to come up with answers rather than simply saying, ‘Well, it will take more time for these applications to be available than for you to reach your exit….’. I always try to find a quantitative citation to show how much time and money still needs to be invested before patients will be able to profit from that kind of futuristic “sci-fi medicine”.

Last week, a very recent source for such information was brought to my attention.  As a contributor to Leaders in Pharmaceutical Business Intelligence I was asked to review and comment on a recent report published in Nature regarding the progress made in the ENCODE project [1]. I was also asked to assess the influence of the progress in understanding the human genome on imaging-based cancer patients’ management, my field of expertise.

This short report is nicely written and is clear to layman’s (which is what I consider myself in this field) reading. My attention was drawn to some important facts:

  • It took 10 years and $288 Million to realise that 80% of 3 Billion DNA bases comprising the human genome serves a purpose.
  • So far a very small percentage (3% to 4%) of this potential was uncovered in the scope of this project.
  • Already now it is clear that much of the “knowledge” regarding the human genome’s functionality will need to be re-written.
  • Researchers anticipate that future studies using advanced technologies will contribute to better estimation of the knowledge gap.
  • Good news: these studies are leading to better understanding of diseases’ pathological characteristics and to more accurate reporting of disease sources. This gives hope to future development of disease specific drug development.

So, back to the subject of this post: it seems to me that we are quite a few decades and many billions of dollars away from “Star-Trek medicine”. In the foreseeable  future, i.e. at least during my life time (and I hope to live a while longer…), the daily routine of cancer patients’ management will have to rely on workflows constituted of screening, diagnosis, a treatment choice that includes a trial and error type of drugs’ choice, and a long-term post treatment follow-up. Smart imaging promises to increase cost efficiency and medical efficacy of these workflows. And I do hope that our children will benefit from the investment our generation is making in understanding the way the human genome is functioning.

  1. Science 7 September 2012: Vol. 337 no. 6099 pp. 1159-1161
    DOI: 10.1126/science.337.6099.1159 http://www.sciencemag.org/content/337/6099/1159.summary?sid=835cf304-a61f-45d5-8d77-ad44b454e448

Written by Dror Nir

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Today’s fundamental challenge in Prostate cancer screening

Author and Curator: Dror Nir, PhD

The management of men with prostate cancer is becoming one of the most challenging public health issues in the Western world. It is characterized by: over-diagnosis; over-treatment; low treatment efficacy; treatment related toxicity; escalating cost; and unsustainability [Bangma et al, 2007; Esserman et al, 2009]. How come? Well, everyone accepts that most prostate cancers are clinically insignificant. It is well known that all men above 65 harbor some sort of prostate cancer. Due to the current aggressive PSA-based screening, one in six men will be diagnosed with prostate cancer. Yet, the lifetime risk of dying of prostate cancer is only 3%. The problem is that, once diagnosed with prostate cancer, there is no accurate tool to identify those men that will die of the disease (in my previous post I mentioned 1:37). Currently, screening practices for prostate cancer are relying on the very unspecific prostate-specific-antigen (PSA) bio-marker test to determine which men are at higher risk of harboring prostate cancer and therefore need a biopsy. The existing diagnostic test is a transrectal ultrasound (TRUS) guided prostate biopsy aimed at extracting representative tissue from areas where cancer usually resides. This procedure suffers from several obvious faults:

1. Since the imaging tool used (B-mode ultrasound) is poor at detecting malignancies in the prostate, the probability of hitting a clinically significant cancer or missing a clinically insignificant cancer is subject to random error.

2. TRUS biopsy is also subjected to systematic error as it misses large parts of the prostate which might harbor cancer (e.g. apex and anterior zones).
3. TRUS guided biopsies are often unrepresentative of the true burden of cancer as either the volume or grade of cancer can be underestimated.

In the last ten years I was leading the development of an innovative ultrasound-based technology, HistoScanningTM, aimed at improving the aforementioned faults;

Among the other most popular imaging modalities aimed at better prostate cancer detection in routine use are: MRIElastography, Contrast Enhanced Ultrasound etc…

In my future posts I will go into more detail on how these imaging modalities fit into routine workflow, how much they stay within budget constraints and what level of promise they bear for promoting personalized medicine. Stay tuned… Footnote: According to the final report by an advisory panel to the USA government: Doctors should no longer offer the PSA prostate cancer screening test to healthy men because they’re more likely to be harmed by the blood draw, and the chain of medical interventions that often follows than be helped; (http://www.usatoday.com/news/health/story/2012-05-21/prostate-cancer-screening-test-harmful/55118036/1) But then; what should be offered instead?

Other posts on this Scientific Website addressing Prostate Cancer

Prostate Cancers Plunged After USPSTF Guidance, Will It Happen Again?

http://pharmaceuticalintelligence.com/2012/07/31/prostate-cancers-plunged-after-uspstf-guidance-will-it-happen-again/

New Prostate Cancer Screening Guidelines Face a Tough Sell, Study Suggests

http://pharmaceuticalintelligence.com/2012/05/27/new-prostate-cancer-screening-guidelines-face-a-tough-sell-study-suggests/

ROLE OF VIRAL INFECTION IN PROSTATE CANCER

http://pharmaceuticalintelligence.com/2012/09/01/role-of-viral-infection-in-prostate-cancer/

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The Incentive for “Imaging based cancer patient’ management”

The Incentive for “Imaging based cancer patient’ management”

Author and Curator: Dror Nir, PhD

Image taken from http://www.breastthermography.com/breast_thermography_mf.htm

It is generally agreed by radiologists and oncologists that in order to provide a comprehensive work-flow that complies with the principles of personalized medicine, future cancer patients’ management will heavily rely on “smart imaging” applications. These could be accompanied by highly sensitive and specific bio-markers, which are expected to be delivered by pharmaceutical companies in the upcoming decade. In the context of this post, smart imaging refers to imaging systems that are enhanced with tissue characterization and computerized image interpretation applications. It is expected that such systems will enable gathering of comprehensive clinical information on cancer tumors, such as location, size and rate of growth.

What is the main incentive for promoting cancer patients’ management based on smart imaging? 

It promises to enable personalized cancer patient management by providing the medical practitioner with a non-invasive and non-destructive tool to detect, stage and follow up cancer tumors in a standardized and reproducible manner. Furthermore, applying smart imaging that provides valuable disease-related information throughout the management pathway of cancer patient will eventually result in reducing the growing burden of health-care costs related to cancer patients’ treatment.

Let’s briefly review the segments that are common to all cancer patients’ pathway: screening, treatment and costs.

 

Screening for cancer: It is well known that one of the important factors in cancer treatment success is the specific disease staging. Often this is dependent on when the patient is diagnosed as a cancer patient. In order to detect cancer as early as possible, i.e. before any symptoms appear, leaders in cancer patients’ management came up with the idea of screening. To date, two screening programs are the most spoken of: the “officially approved and budgeted” breast cancer screening; and the unofficial, but still extremely costly, prostate cancer screening. After 20 years of practice, both are causing serious controversies:

In trend analysis of WHO mortality data base [1], the authors, Autier P, Boniol M, Gavin A and Vatten LJ, argue that breast cancer mortality in neighboring European countries with different levels of screening but similar access to treatment is the same: “The contrast between the time differences in implementation of mammography screening and the similarity in reductions in mortality between the country pairs suggest that screening did not play a direct part in the reductions in breast cancer mortality”.

In prostate cancer mortality at 11 years of follow-up [2],  the authors,Schröder FH et. al. argue regarding prostate cancer patients’ overdiagnosis and overtreatment: “To prevent one death from prostate cancer at 11 years of follow-up, 1055 men would need to be invited for screening and 37 cancers would need to be detected”.

The lobbying campaign (see picture below)  that AdmeTech (http://www.admetech.org/) is conducting in order to raise the USA administration’s awareness and get funding to improve prostate cancer treatment is a tribute to patients’ and practitioners’ frustration.

 

 

 

Treatment: Current state of the art in oncology is characterized by a shift in  the decision-making process from an evidence-based guidelines approach toward personalized medicine. Information gathered from large clinical trials with regard to individual biological cancer characteristics leads to a more comprehensive understanding of cancer.

Quoting from the National cancer institute (http://www.cancer.gov/) website: “Advances accrued over the past decade of cancer research have fundamentally changed the conversations that Americans can have about cancer. Although many still think of a single disease affecting different parts of the body, research tells us through new tools and technologies, massive computing power, and new insights from other fields that cancer is, in fact, a collection of many diseases whose ultimate number, causes, and treatment represent a challenging biomedical puzzle. Yet cancer’s complexity also provides a range of opportunities to confront its many incarnations”.

Personalized medicine, whether it uses cytostatics, hormones, growth inhibitors, monoclonal antibodies, and loco-regional medical devices, proves more efficient, less toxic, less expensive, and creates new opportunities for cancer patients and health care providers, including the medical industry.

To date, at least 50 types of systemic oncological treatments can be offered with much more quality and efficiency through patient selection and treatment outcome prediction.

Figure taken from presentation given by Prof. Jaak Janssens at the INTERVENTIONAL ONCOLOGY SOCIETY meeting held in Brussels in October 2011

For oncologists, recent technological developments in medical imaging-guided tissue acquisition technology (biopsy) create opportunities to provide representative fresh biological materials in a large enough quantity for all kinds of diagnostic tests.

 

Health-care economics: We are living in an era where life expectancy is increasing while national treasuries are over their limits in supporting health care costs. In the USA, of the nation’s 10 most expensive medical conditions, cancer has the highest cost per person. The total cost of treating cancer in the U.S. rose from about $95.5 billion in 2000 to $124.6 billion in 2010, the National Cancer Institute (www.camcer.gov) estimates. The true sum is probably higher as this estimate is based on average costs from 2001-2006, before many expensive treatments came out; quoting from www.usatoday.com : “new drugs often cost $100,000 or more a year. Patients are being put on them sooner in the course of their illness and for a longer time, sometimes for the rest of their lives.”

With such high costs at stake, solutions to reduce the overall cost of cancer patients’ management should be considered. My experience is that introducing smart imaging applications into routine use could contribute to significant savings in the overall cost of cancer patients’ management, by enabling personalized treatment choice and timely monitoring of tumors’ response to treatment.

 

 References

  1. 1.      BMJ. 2011 Jul 28;343:d4411. doi: 10.1136/bmj.d4411
  2. 2.      (N Engl J Med. 2012 Mar 15;366(11):981-90):

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Reported by: Dr. Venkat S. Karra, Ph.D.

 

Brain structures involved in dealing with fear...

 

Major depression or chronic stress can cause the loss of brain volume, a condition that contributes to both emotional and cognitive impairment. Now a team of researchers led by Yale University scientists has discovered one reason why this occurs—a single genetic switch that triggers loss of brain connections in humans and depression in animal models.

 

The findings, reported in Nature Medicine, show that the genetic switch known as a transcription factor represses the expression of several genes that are necessary for the formation of synaptic connections between brain cells, which in turn could contribute to loss of brain mass in the prefrontal cortex.

 

“We wanted to test the idea that stress causes a loss of brain synapses in humans,” said senior author Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and professor of neurobiology and of pharmacology. “We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated.”

 

The research team analyzed tissue of depressed and non-depressed patients donated from a brain bank and looked for different patterns of gene activation. The brains of patients who had been depressed exhibited lower levels of expression in genes that are required for the function and structure of brain synapses. Lead author and postdoctoral researcher H.J. Kang discovered that at least five of these genes could be regulated by a single transcription factor called GATA1. When the transcription factor was activated, rodents exhibited depressive-like symptoms, suggesting GATA1 plays a role not only in the loss of connections between neurons but also in symptoms of depression.

 

Duman theorizes that genetic variations in GATA1 may one day help identify people at high risk for major depression or sensitivity to stress.

 

“We hope that by enhancing synaptic connections, either with novel medications or behavioral therapy, we can develop more effective antidepressant therapies,” Duman said.

 

source:

 

http://www.rdmag.com/News/2012/08/Life-Sciences-Team-Discovers-How-Stress-Depression-Can-Shrink-The-Brain/

 

 

 

 

 

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Reported by: Dr. Venkat S. Karra, Ph.D.

Mitochondria are responsible for more than 90% of a cell’s energy production via ATP (adenosine triphosphate) generation, in addition to playing a significant role in respiration and many signaling events within most eukaryotic cells. These intracellular powerhouses range in size and quantity within each cell depending on the organism and overall cell function.

Mitochondria consist of a semi-permeable outer membrane, a thin inter-membrane space where oxidative phosphorylation occurs, an impermeable inner membrane that is intricately folded to create layered compartments—or christae—and the matrix that contains ATP-producing enzymes and the organelle’s own independent genome. Each section has a highly specialized function, and any impairment within the organelle can lead to disease or disorders within the overall organism.

Mitochondrial dysfunction may be due to:

1. Hereditary:

Inherited mitochondrial disorders can play a role in prevalent diseases such as cardiac disease and diabetes, and can also result in rare diseases such as Pearson syndrome or Leigh’s disease.

2. Drug Toxicity:

Mitochondrial toxicity as a result of pharmaceutical use may damage key organs, such as the liver and heart. For example:

nefazodone—a depression treatment—was withdrawn from the U.S. market after it was shown to significantly inhibit mitochondrial respiration in liver cells, leading to liver failure.

Troglitazone, an anti-diabetic and anti-inflammatory, was withdrawn from all markets after research concluded that it caused acute mitochondrial membrane depolarization, also leading to liver failure.

Drug recalls are costly to a manufacturer’s bottom line and reputation, and more importantly, can be harmful or even fatal to users. As drug discovery continues to evolve, much lead compound research now includes careful review of its interaction and potential toxicity with mitochondria.

Cell-based mitochondrial assays in microplate format may include mitochondrial membrane potential, total energy metabolism, oxygen consumption, and metabolic activity; and offer a truer environment for mitochondrial function in the presence of drug compounds compared to isolated mitochondria-based tests. Combining more than one assay in a multiplex format increases the amount of data per well while decreasing data variability arising from running the assays separately. The aggregated data also provides a more encompassing analysis of the drug’s effect on mitochondria than a single test.

One example, when testing compound effects on mitochondria, would be to measure cell membrane integrity as a function of cytotoxicity and mitochondrial function via ATP production concurrently, thus distinguishing between compounds that exhibit mitochondrial toxicity versus overt cytotoxicity.

General cytotoxicity is characterized by a decrease in ATP production and a loss of membrane integrity whereas mitochondrial toxicity results in decreased ATP production with little to no change in membrane integrity.

The assay’s efficiency is further enhanced via automation.

Robotic instrumentation ensures repeatable operation within the microplate wells when performing tasks such as cell dispensing, serial titration and transfer of compounds, and reagent dispensing. Additionally, by automating tasks within the assay process, researchers are free to attend to other tasks, reducing overall active time spent on the assay. Multi-mode microplate readers are compact instruments that can detect both fluorescent and luminescent signals. In addition, an automated process—including liquid handling and detection—can increase throughput capacity compared to manual methods.

Multiplexed cell-based mitochondrial assays increase sample throughput and decrease variability, costs, and overall time for project completion. Automating the process with robotic instrumentation allows for rapid compound profiling, repeatability, further throughput increase, and decreased per-assay and overall project time.

source:

http://www.dddmag.com/articles/2012/08/detecting-potential-toxicity-mitochondria?et_cid=2794933&et_rid=45527476&linkid=http%3a%2f%2fwww.dddmag.com%2farticles%2f2012%2f08%2fdetecting-potential-toxicity-mitochondria

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Reported by: Dr. Venkat S.Karra, Ph.D.

Last August, UPenn scientists announced the dramatic results of a tiny clinical trial of their immunotherapy approach, describing long-lasting remissions in leukaemia patients for whom standard therapies had stopped working. Trials are also underway for other leukaemias and for lymphoma, mesothelioma, myeloma and neuroblastoma, according to the university.

The therapy developed by UPenn’s Carl June is complicated. Vaccines prompt a patient’s immune system to attack dangerous cells through an approach, called chimeric-antigen-receptor immunotherapy – a genetically redesigned immune cells for a more powerful attack. In this therapy first, blood is collected from leukaemia patients and exposed to substances that activate T cells, powerful cells that launch and coordinate immune attacks. Next, the T cells are genetically modified to recognize and attack leukaemia cells. Finally, the altered cells are returned to the patient, where they are expected to proliferate until the cancer cells are gone.

Drug giant Novartis is making a multimillion dollar bet that a patient’s immune system can be cancer’s worst enemy. It is teaming up with scientists at the University of Pennsylvania (UPenn) in Philadelphia to develop and manufacture cancer immunotherapies.

In the US$20-million collaboration, announced today, Novartis, which is based in Basel, Switzerland, will get exclusive worldwide rights to these technologies.

source

http://blogs.nature.com/news/2012/08/novartis-gives-upenn-20-million-for-cancer-vaccine.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+news%2Frss%2Fnewsblog+%28News+Blog+-+Blog+Posts%29&WT.ec_id=NEWS-20120807

 

 

 

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Reported by: Dr. Venkat S. Karra, Ph.D.

A new proof-of-concept study shows that plasma concentrations of precursor fragments of the neuropeptide enkephalin (proenkephalin A, or PENK-A) are elevated in patients with acute stroke compared with those with TIA and nonischemic events.

Researchers are making efforts to investigate neuropeptides in patients presenting with symptoms of acute cerebrovascular disease.

Although the mature neuropeptides are degraded within minutes, their precursor fragments are much more stable and represent neuropeptide synthesis in stoichiometric relations. “They are therefore well suited as biomarkers and may be suitable for measurement in clinical settings,” said Dr. Doehner.

The precursor neuropeptides proenkephalin A (PENK-A) and protachykinin (PTA) are markers of blood-brain barrier integrity and have been recently discussed in vascular dementia and neuroinflammatory disorders.

{Ernst  A., Kohrle  J., Bergmann  A.;  Proenkephalin A 119—159, a stable proenkephalin. A precursor fragment identified in human circulation, Peptides 27 2006 1835-1840
Ernst  A., Suhr  J., Kohrle  J., Bergmann  A.;  Detection of stable N-terminal protachykinin A immunoreactivity in human plasma and cerebrospinal fluid, Peptides 29 2008 1201-1206}

Researchers are making efforts to use these precursor fragments as markers to distinguish an ischemic stroke from a transient ischemic attack (TIA) or an intracerebral hemorrhage.

The authors strongly hope that it may help to advance the use of biomarkers in the clinical evaluation of stroke patients.

Despite the limitations, elevated PENK-A levels correlated with stroke severity and with brain lesion size, and they predicted mortality and more functional disability.

“There is clearly an unmet need to establish biomarker-guided prognostic and functional evaluations for patients with stroke, said the lead author Wolfram Doehner, MD, PhD, from the Center for Stroke Research, in Berlin, Germany

The new report was published in Journal of the American College of Cardiology.

http://content.onlinejacc.org/article.aspx?articleid=1217869

http://www.medscape.com/viewarticle/768457?src=nldne

 

 

 

 

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Guidelines for the Diagnosis and Treatment of Endocarditis

from

British Society of Antimicrobial Chemotherapy (BSAC)

Clinicians who care for patients diagnosed with infective endocarditis (IE) are (un)fortunate to be able to refer to several guidelines about its diagnosis and treatment. The guidelines vary considerably, especially with regards to antibiotic prescribing recommendations, which generally reflect local practice and expert opinion in light of largely observational data. All guidelines recommend a multidisciplinary approach to the management of IE.

Infective endocarditis

Infective endocarditis (Photo credit: Wikipedia)

Echocardiography remains a cornerstone of IE diagnosis but is neither 100% sensitive nor specific and multiple scans may be needed to identify vegetations. Echocardiography should also be used in all patients with Staphylococcus aureus bacteraemia. The prevalence of IE among patients with S aureus bacteraemia is variable but was reported as 13% in one large prospective US study and 22% in a recent European study. Clinical assessment is unreliable in diagnosing IE in patients with S aureus bacteraemia and without echocardiography the diagnosis may be missed. Transoesophageal echocardiography is now recommended in most cases of suspected or confirmed IE but may be unnecessary in patients with right-sided valve involvement.

Establishing a microbiological diagnosis in an era of increasingly complex infections with unpredictable resistance patterns is important. However, traditional recommendations for blood culture sampling have been amended for patients with suspected IE and severe sepsis or septic shock. In this situation, two (rather than three) sets of blood cultures, taken at different times within an hour before the start of empirical treatment, are now advised. This is a pragmatic recommendation to avoid undue delay in starting empirical antimicrobial treatment. In other patients, the usual need for three sets of blood cultures is recommended but with at least 6 h between sampling times; an important aim of multiple sampling is to demonstrate the presence of a sustained or persistent bacteraemia, which is characteristic of IE. Identification of atypical micro-organisms using serology in culture-negative cases should be limited to Coxiella and Bartonella in the first instance—a reflection of the extremely small numbers of reported cases of IE caused by Mycoplasma, Brucella and Legionella.

Fungal causes of IE should be considered in culture-negative IE if serology is non-diagnostic and the patient is immunocompromised, has a prosthetic valve, is an intravenous drug user or is not responding to empirical antibacterial treatment. The application of broad-range (16S ribosomal RNA gene) PCR on surgically resected valves or embolic material should be used when culture has failed. False-negative 16S ribosomal RNA gene PCR reactions can occur in the presence of inhibitors of the DNA polymerase within clinical samples or as a result of the vagaries of sampling (ie, processing a piece of tissue that does not contain any bacteria). Bacterial DNA has been shown to be present within cardiac tissue several years after successful treatment of IE, so results should be interpreted with caution in a patient with a previous diagnosis of IE. Application of 16S ribosomal gene PCR to blood in patients with IE is problematic owing to the low levels of bacteria present (1–10 fu/ml) and subsequent difficulty in DNA extraction; as a result it is not currently available for routine clinical use.

Empirical treatment (that started before obtaining a microbiological diagnosis) is generally discouraged, except in those who are acutely unwell or shocked. There is no clear evidence that speeding up the diagnosis, and instigation of treatment, improves outcomes, although this would seem intuitive. Early treatment (started within days of onset of symptoms rather than weeks) is a laudable aim, but the few days delay in hospital while appropriate echocardiographic and microbiological tests are undertaken on a stable patient are unlikely to have a negative impact on outcome. Conversely, the administration of broad-spectrum antibiotics when the diagnosis of IE has not been considered (and often when inadequate samples have been obtained) may have considerable impact on the ability to establish the diagnosis and subsequently deliver effective treatment.

Outpatient antibiotic treatment (OPAT) for IE is included in the BSAC guidelines in response to increasing efforts to expand these services and manage more patients outside hospital. Patients who might be considered for OPAT include those who are stable and responding well to treatment, are without signs of heart failure and without any indications for surgery or uncontrolled extracardiac foci of infection. Delivery of OPAT requires appropriate funding, support and infrastructure, coupled with the ability to rapidly access inpatient services and obtain urgent expert advice if needed. This has been proved to be feasible and safe in the UK, even in high-risk IE cases.

Although the guidelines include recommendations for most causes of IE, the predominant pathogens remain staphylococci, streptococci and enterococci. Routine addition of gentamicin to flucloxacillin for the treatment of native valve staphylococcal IE is no longer recommended (see Table 1). This recommendation is unchanged from previous BSAC guidelines but the ESC continue to include gentamicin as an optional addition. Further evidence of the toxicity of gentamicin has been published, based on findings from a randomised controlled trial comparing daptomycin with either vancomycin or cloxacillin plus gentamicin for the treatment of S aureus bloodstream infection or IE Recommendations for meticillin-resistant staphylococci also differ from those of the ESC; although vancomycin is the primary agent in both sets of guidelines, rifampicin is recommended by BSAC in place of gentamicin because of concerns about efficacy and toxicity. Daptomycin, a recently licensed lipopeptide, is also recommended as an alternative agent for patients who are intolerant to vancomycin or have infection caused by vancomycin-resistant isolates.

Previous recommendations for treatment of streptococcal IE have been simplified, with greater emphasis placed on benzylpenicillin rather than amoxicillin as the primary agent to reduce risk of Clostridium difficile infection. Enterococcal treatment regimens are largely consistent with the ESC guidelines, though a low threshold for withdrawing gentamicin in patients with deteriorating renal function or other signs of toxicity is advised, based on observational data that shorter gentamicin courses are not associated with worse outcomes.

The timing of cardiac surgery in IE should be evaluated by the multidisciplinary team on a case by case basis. Attempts to advise whether cardiac surgery should be emergent, urgent or elective can seem artificial. The traditional indications for surgery in IE are well established but it is becoming apparent that patients with IE caused by S aureus, or patients with evidence of systemic embolisation, should also be considered for early surgery, which may confer a mortality benefit.

Device-related infections have been deliberately omitted from the current BSAC guidance as the challenges in preventing, diagnosing and treating cases of intracardiac device IE are different from ‘traditional’ native or prosthetic valve IE. Further specific device-related guidance is likely to be published in the future and a joint working party involving the BSAC, BCS and Heart Rhythm UK has been established. IE guidelines are always imperfect owing to the difficulties in studying this relatively uncommon condition and the scarcity of randomised trials. At present, we are uncertain of the incidence, risk factors, causative micro-organisms (and their antimicrobial sensitivities), and patient outcomes in IE affecting the UK population. A recently established national endocarditis database may help to answer some of these questions, but its success will be crucially determined by the degree of support and national participation. See http://www.neemo.leedsth.nhs.uk/ (only via the N3 network) for details.

see source for more

Reported by: Dr. V. S. Karra, Ph.D

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