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Biomedical subjects

H I Cohen

Publications and source records attributed to H I Cohen.

At least 19 recordsLinked to original sources
PubMed2005

Primary local orbital amyloidosis: biochemical identification of the immunoglobulin light chain kappaIII subtype in a small formalin fixed, paraffin wax embedded tissue sample.

BACKGROUND: Amyloidosis refers to a heterogeneous group of disorders associated with the deposition of chemically distinct amyloid fibril proteins. Precise determination of chemical amyloid type has diagnostic, therapeutic, and prognostic relevance. Although immunohistochemical techniques are used routinely to determine the amyloid type, the results can be negative or inconclusive, so that biochemical characterisation is often required. The development and application of new biochemical microtechniques suitable for examination of extremely small tissue samples is essential for precise identification of the deposited amyloid proteins. AIMS: To investigate biochemically the amyloid proteins present in a formalin fixed paraffin wax embedded orbital tissue from a patient with localised orbital amyloidosis in whom immunohistochemistry was not helpful in the determination of amyloid type. METHODS: Extraction of amyloid proteins from fixed tissue and their identification was carried out by a recently developed microtechnique. An extremely small tissue sample was dewaxed and extracted with formic acid. The extracted material was analysed using electrophoresis, western blotting, and amino acid sequencing. RESULTS: Biochemical examination of the extracted proteins showed the presence of immunoglobulin (Ig) derived amyloid proteins, which were composed of the N-terminal fragments of the Ig light chain kappaIII subtype (AL-kappaIII) (16, 8, and 3 kDa). CONCLUSIONS: This is the first chemically proved AL case reported in association with primary localised orbital amyloidosis. The biochemical microtechnique used was useful in achieving a precise diagnosis of amyloid disease, in a case where the results of routine immunohistochemical examination of amyloid were inconclusive.

Adult↗
PubMed2001

Leprosy in Israel: an imported disease--the support of histopathological examination for its detection.

Leprosy is rare and non-endemic in Israel. Cases of leprosy are invariably imported by immigrants or foreign workers arriving from endemic areas. In view of the relative rarity of the disease, clinicians and pathologists are not always alert to the possibility of the disease or recognize potential symptoms. A case history is presented of a 31-year-old immigrant presenting symptoms of skin lesions and nodules on the hands and facial region, especially the ear lobe. Confirmation of the infection was provided by histopathology of suspected lesions stained for acid-fast bacilli (modified Fite-Faraco staining).

Adult↗
PubMed2001

Mesna: a novel renoprotective antioxidant in ischaemic acute renal failure.

BACKGROUND: Reactive oxygen species (ROS) play a key role in renal ischaemia-reperfusion injury. After establishing the in vitro anti-oxidative potential of mesna, a sulfhydryl-containing compound, its effect on kidney function and morphology in a rat model of ischaemic acute renal failure (ARF) was examined. METHODS: Mesna (180 mg/kg) was administered at different time points relative to ischaemia and/or reperfusion onset. Kidney function was assessed by glomerular filtration rate (GFR) and fractional sodium excretion (FE(Na)) before a 45-min period of unilateral renal artery clamping and following 90 min of reperfusion. Mesna was administered by bolus, 30 min before the induction of ischaemia, 5 min before ischaemia, 5 min before reperfusion, and 5 min after the onset of reperfusion. RESULTS: Mesna improved function of the ischaemic kidney at each administration. When mesna was administered 5 min before the onset of reperfusion, GFR reached 90-100% of its pre ischaemic value and FE(Na) was improved by 75%. The beneficial effect of mesna was also demonstrated by light and electron microscopy. Kidneys treated with mesna 5 min before reperfusion resembled ischaemic non-reperfused kidneys and showed subtle morphological and ultrastructural changes compared with ischaemic-reperfused kidneys. Mesna had no haemodynamic effect on renal blood flow and did not induce any osmotic diuresis. CONCLUSIONS: We suggest that mesna acts as an antioxidant. Its antioxidant potential together with optimal protection achieved when administered 5 min before reperfusion, supports the conclusion that mesna scavenges ROS generated at the onset of reperfusion, thus diminishing reperfusion injury and organ damage.

Acute Kidney Injury↗
PubMed2001

Nimesulide-induced acute hepatitis.

OBJECTIVE: To report the occurrence of nimesulide-induced acute hepatitis confirmed by biopsy and an in vitro lymphocyte toxicity assay. CASE SUMMARY: A 54-year-old Arabic woman treated with nimesulide for chronic low back pain was admitted to the hospital with acute hepatitis confirmed by biopsy. Her liver function test results returned to normal within one month after nimesulide discontinuation. An in vitro lymphocyte toxicity assay confirmed that the liver injury was due to nimesulide exposure. DISCUSSION: A case of acute hepatitis secondary to nimesulide, confirmed by biopsy and a laboratory in vitro assay, is described. Although the occurrence of clinically significant liver damage due to nonsteroidal antiinflammatory drugs (NSAIDs) is low, the enormous consumption of these drugs has made them an important cause of liver damage. Nimesulide, a relatively new NSAID commonly used in Europe, with a relative selectivity to cyclooxygenase type 2, can cause a wide range of liver injuries, from mild abnormal liver function to severe liver injuries. These effects are usually reversible on discontinuation of the drug, but occasionally can progress to fatal hepatic failure. CONCLUSIONS: Drug-induced acute hepatitis is a well-recognized adverse effect of many drugs, including nimesuilde. Identification of a drug as a cause for this life-threatening disease is important because the discontinuation of it may be life saving. This article confirms the occurrence of nimesulide-induced hepatitis. It also highlights the importance of monitoring liver function test results after initiating therapy with such a drug.

Acute Disease↗
PubMed1993

Dermatofibrosarcoma protuberans appearing during pregnancy.

Dermatofibrosarcoma protuberans is an uncommon skin tumor with a high potential for local recurrence if not adequately excised. There are only two reports in the literature describing dermatofibrosarcoma protuberans that enlarged considerably during pregnancy. On the other hand, the new development or enlargement of dermatofibromas in pregnancy is well documented. We present 2 additional patients in whom a dermatofibrosarcoma protuberans appeared and grew rapidly during pregnancy. Immunohistochemical studies were negative for estrogen and progesterone receptors. The possible pathophysiology and surgical management are presented and discussed.

Adult↗
PubMed1985

Comparison of signal and adaptive sensitivity profiles of the surround mechanism of cat retinal ganglion cells.

Signal and adaptive sensitivity profiles of the surrounds of cat retinal ganglion cells were determined by varying the position of concentric annuli whose outside and inside diameters varied but whose total area remained constant. Signal sensitivity profiles were determined by adjusting the luminances of these annuli so as to produce a weak suprathreshold response of constant magnitude and time course. Adaptive sensitivity profiles were determined by varying the luminances of concentric equal-area, unmodulated annuli until the response to a temporally modulated annulus attained a criterion level. The results provided evidence that the retinal region over which the surround mechanism of an X cell pools adaptive information and pools signals are the same, and that the distribution of adaptive and signal sensitivities within these regions is similar. A small number of X cells showed local adaptation effects. The adaptive pooling area appeared to be smaller than the signal pooling area for Y cells.

Adaptation, Physiological↗
PubMed1982

Tuberculosis and lung cancer risk in nonsmoking women.

We ascertained prior pulmonary tuberculosis infection in 211 non-Caucasian female lung cancer patients and 419 sex, race, ape, smoking history and birthplace-matched control subjects by searching the Hawaii State Tuberculosis Branch patient records. Among never-smokers we found a significant increase in risk associated with prior tuberculous infection (odds ratio, 8.2; 95% confidence limits = 1.3 to 54.4). No such association was found among smokers. Prior tuberculous infection was identified in only 5.5% of never-smoking lung cancer patients, however, suggesting that this factor is a relatively unimportant contributor to the etiologic aspects of lung cancer in persons who have never smoked.

China↗
PubMed1981

Spatial summation of signals and adaptation by the surround response mechanism of cat retinal ganglion cells.

The summing properties of the surround response mechanism of cat retinal ganglion cells were assessed by determining area-sensitivty and area-adaptation curves. The two curves were found to be similar for X and Y cells but for many Y cells adaptive sensitivity was found to be dependent upon the size of the test target. These results suggest that, for X cells, the retinal area over which the surround integrates signals and adaptation are spatially coextensive. Most Y cells appear to pool adaptive effects over a smaller region than they pool signals.

Acclimatization↗
PubMed1980

Response of X and Y cat retinal ganglion cells to moving stimuli.

Single optic tract fibers in the cat were classified as X or Y cells by a contrast reversal stimulus. A slit of light was then moved across the receptive field at velocities from 10--1000 degrees/s. The preferred velocity was that velocity which elicited the strongest response from the cell. The maximum velocity was the highest velocity target to which a cell could respond. Y cells as a group both preferred and could follow faster targets than X cells, and were more broadly tuned to the preferrred velocity.

Animals↗
PubMed1979

Effect of adapting target size on the gain of the surround response mechanism in X- and Y-cells in cat retina.

The adaptation field of the surround mechanism of X and Y retinal ganglion cells in the cat was assessed with variable size, unmodulated adapting spots. Both an on-inhibition measure and an off-discharge measure of surround gain was used. Results suggest that the surround mechanism in Y-cells is strongest in the receptive field middle but weak or nonexistent in the middle of X-cell receptive fields.

Animals↗