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Biomedical subjects

N Cohen

Publications and source records attributed to N Cohen.

At least 145 records · Page 8Linked to original sources
PubMed1994

Cavernous angiomas of the internal auditory canal. A case report and review of literature.

Cavernous angiomas of the internal auditory canal (IAC) are rare. They are angiographically occult; and because the clinical symptoms are similar both in intracanalicular cavernous angiomas and acoustic tumors it had been difficult to differentiate pre-operatively both of these pathologies until the advent of magnetic resonance imaging (MRI). Even nowadays the correct diagnosis may be missed if the patient is imaged only with gadolinium enhanced MRI without prior obtaining a non-contrast MRI. These diagnostic difficulties are illustrated by the report of a related case. The importance of thorough neuroradiological investigations stressed and MRI features, surgical management and relevant literature concerning the cavernous angiomas of the internal auditory canal are discussed.

Adult↗
PubMed1994

Quantitative differences in interleukin-2 and interleukin-4 production by antigen-stimulated splenocytes from individually- and group-housed mice.

The effects of differential housing on T-helper (TH) cell activation were investigated. BALB/c and C57Bl/6 male mice housed 1 or 4 per cage were administered three i.p. injections of keyhole limpet hemocyanin (KLH) over several weeks. Effects of differential housing on in vitro antigen-specific interleukin (IL)-2 (a TH1 cell derived cytokine) and IL-4 (a TH2 cell derived cytokine) production were observed. BALB/c mice housed alone produced significantly more IL-4 than BALB/c mice housed in groups. C57Bl/6 mice housed alone produced significantly more IL-2 than C57Bl/6 mice housed in groups. Differential housing did not influence either IL-2 production among BALB/c mice or IL-4 production among C57Bl/6 mice. These data demonstrate that environmental conditions can influence cytokine production by both TH-1 dominant (C57Bl/6) and TH-2 dominant (BALB/c) mice.

Animals↗
PubMed1994

CO2 anesthesia facilitates a serum antibody response to orally-administered antigens.

Under most experimental circumstances, mice fed a protein antigen produce a smaller serum antibody response than the response elicited in mice that are parenterally immunized with that same antigen. In our experiments, mice fed keyhole limpet hemocyanin or herpes simplex virus type 1 had low, if any, serum IgG antibody responses regardless of whether antigen consumption was voluntary (in drinking fluids) or involuntary (force-fed by pipette). However, when force-feeding occurred during CO2 anesthesia, mice produced significantly higher serum antibody responses, which were comparable to those elicited in mice injected intraperitoneally with the same antigen. Although its mechanism of action is unclear, this potentiating effect does not appear to be mediated by possible CO2-mediated entry of the antigens into the respiratory tract, since mice fed antigen immediately before CO2 anesthesia also had a substantial antibody response.

Adjuvants, Immunologic↗
PubMed1994

Alterations in interleukin-4 and antibody production following pheromone exposure: role of glucocorticoids.

We have previously shown that exposure to pheromones from footshock-stressed mice suppresses cell-mediated immunity and enhances humoral immunity. Here we show that stress odor exposure is associated with enhanced antigen-specific antibody production and interleukin (IL)-4 production in BALB/c, but not C57Bl/6, mice. Glucocorticoid receptor antagonism blocks the enhancement of IL-4, but not antibody titers. There is an apparent differential sensitivity of BALB/c and C57Bl/6 spleen cells to in vitro incubation with the synthetic glucocorticoid dexamethasone; IL-2 production by BALB/c spleen cells is more sensitive to the effects of steroid. These data suggest that C57Bl/6 mice may not respond to stress pheromones due to their relative insensitivity to endogenous steroids.

Animals↗
PubMed1994

Physician use of a computerized medical record system during the patient encounter: a descriptive study.

The computerized medical record program, CLINIC, specifically designed at Ben-Gurion University of the Negev to be used on-line in a primary care clinic during a patient encounter by healthcare professionals, has been in use for over 6 years in two community clinics. In order to analyse the effectiveness and use of CLINIC, four physicians were video recorded during working sessions before and after the introduction of CLINIC. While using CLINIC did not change the total mean encounter time, the lengths of the encounter components and record use did change. The physicians' work style changed from a 'conversational pattern' (continuous data recording) to a 'blocked pattern' (data entry at intervals).

Attitude of Health Personnel↗
PubMed1994

Pancreatic enzyme elevation in measles.

During an outbreak of measles in the period from May 1993 through February 1994, a 23-year-old woman with measles was admitted because of abdominal pain and vomiting. Moderately elevated levels of serum and urinary amylase were found. We investigated prospectively the next nine consecutive young adults hospitalized with severe measles. Pancreatic and other organ involvement was determined by serum and urinary amylase, serum lipase, and additional appropriate biochemical and hematological data. Four patients had elevated amylase levels in both serum and urine, whereas in one, serum amylase alone was increased. Serum lipase determined in eight patients was elevated in seven. In all patients elevated serum levels of aspartate aminotransferase and alanine aminotransferase or lactate dehydrogenase were found. In seven patients serum calcium concentrations were below the lower limit of normal. Four patients had mild to moderate thrombocytopenia. This is the first detailed report of pancreatic involvement in young adults with measles. This abnormal finding, its possible underlying mechanisms, and the clinical significance are discussed.

Adult↗
PubMed1994

Pavlovian conditioning of the immune system.

In the classical Pavlovian conditioning paradigm, a stimulus that unconditionally elicits a physiological response is repeatedly paired with a neutral stimulus that does not elicit that same response. Eventually, the neutral stimulus becomes a conditioned stimulus in that it elicits the physiological response in the absence of an unconditioned stimulus. Here we summarize experiments in which Pavlovian conditioning has revealed an intimate relationship between the central nervous system and the immune system.

Animals↗
PubMed1994

Six mutations in the glucokinase gene identified in MODY by using a nonradioactive sensitive screening technique.

We have reported that 56% of French families with maturity-onset diabetes of the young (MODY) carry a mutation in the glucokinase gene (GCK). Therefore, we have established a quick and sensitive nonradioactive technique (with the PhastSystem based on single-strand conformation polymorphism [SSCP] analysis) to routinely screen the 12 exons of GCK for mutations. We have studied GCK in 12 young hyperglycemic patients with a strong family history of type II diabetes. SSCP variants were observed in 6 of those 12 patients (50%), which cosegregated with diabetes in five families where DNA from additional members was available. Direct sequencing identified a 10-bp (base pair) deletion in exon 3; a 33-bp deletion at the exon 5/intron 5 junction, including the two consensus bases (GT) of the donor splice site; a nonsense mutation in exon 5 (Arg186-->Stop) in a Black-African family, which has been identified previously in a Caucasian family; and three missense mutations: Thr209-->Met209 in exon 6, Gly261-->Glu261 in exon 7, and Arg36-->Trp36 in exon 2. The missense mutation in exon 2 was found only in the second and third generation of the tested family but not in the first. To our knowledge, this is the first time that a de novo mutation of GCK is reported within a family. All six families carrying a mutation in GCK were typical MODY and most of their affected members had a mild form of diabetes. This nonradioactive SSCP technique may be useful to routinely diagnose glucokinase deficiency, which is an important cause of hyperglycemia among young type II diabetic patients.

Adult↗
PubMed1994

[Hemodynamic effects of chronic treatment by cilazapril in normotensive patients with obliterative arterial diseases of the lower limbs].

OBJECTIVE: To determine whether long-term treatment with cilazapril (CIL) may improve pulse pressure (PP), arterial compliance and ankle-arm systolic index (AAI) in patients with lower-extremity arterial disease (LEAD). Indeed, in both systolic hypertension and LEAD, the increase in pulse pressure has been attributed to a reduced compliance. DESIGN AND METHODS: Thirteen patients (age: 65 +/- 5 yrs; AAI: 0.78 +/- 0.15; m +/- SD) were included in a double-blind randomized parallel study to compare the effects of a 6 month treatment with CIL (10 mg per day; n = 6) to those of placebo (PL; n = 7) Blood pressure, AAI and arterial compliance were determined at baseline (MO) and after 3 (M3) and 6 months (M6). Common carotid (CC) and common femoral (CF) artery compliances were noninvasively determined from pulsatile changes in arterial diameter (Wall Track System, Hoeks et al., 1990) and pressure (PP). RESULTS: Both groups were comparable at MO. Compared to PL, CIL significantly reduced PP (-22 +/- 4 vs -2 +/- 9 mmHg) and MAP (-16 +/- 11 vs -4 +/- 7 mmHg) and improved CC (+54 +/- 34 vs +5 +/- 21 mm2.mmHg-1.10(-3)) at M6. Weaker effects were observed at M3. No significant changes in AAI and CF compliance were observed. CONCLUSIONS: A direct effect of CIL on the large artery wall was suggested by 1) a greater reduction in PP than in MAP and 2) a disproportionately greater improvement in CC compliance compared with the reduction in distending pressure (MAP). These results indicate that long-term treatment with CIL may improve large artery function in patients with LEAD.

Adult↗
PubMed1994

Effects of iodized oil on trivalent oral polio vaccine in vitro.

Iodine deficiency can be effectively reversed by administration of iodized oil (IO). Since 1989, the WHO Expanded Programme on Immunization recommended delivery of oral IO along with vaccines, in appropriate situations. However, administration of IO at the same time as trivalent oral polio vaccine (TOPV) has not been recommended because of absence of studies addressing potential harmful effects of iodized oil on immuno-responses to TOPV. In this study an in-vitro cell culture system was used to measure possible adverse effects of IO on TOPV. The system itself was shown not to be influenced by either IO or a standard non-iodized oil (NIO). However, marked effects of IO on virus infectivity was measured when a 50% mixture of IO and TOPV was incubated for 48 h at 37 degrees C, as compared to incubation without IO. Clear differences were found in effects of IO on vaccines of different sources, suggesting differences in composition of these vaccines, e.g. in stabilizers. Principally Sabin 3 appeared susceptible to IO under the given extreme conditions. Pre-dilution of the IO-TOPV mixture prior to incubation clearly reduced the effects of IO on virus infectivity Inoculation of the IO/TOPV-mixture directly onto susceptible cells, a model approaching the in vivo situation, resulted in no detrimental effects on virus infectivity. Further studies are planned looking at interactions of iodized oil and TOPV in children at immunization contacts.

Cell Line↗
PubMed1994

The algorithmic complexity of neural spike trains increases during focal seizures.

The interspike interval spike trains of spontaneously active cortical neurons can display nonrandom internal structure. The degree of nonrandom structure can be quantified and was found to decrease during focal epileptic seizures. Greater statistical discrimination between the two physiological conditions (normal vs seizure) was obtained with measurements of context-free grammar complexity than by measures of the distribution of the interspike intervals such as the mean interval, its standard deviation, skewness, or kurtosis. An examination of fixed epoch data sets showed that two factors contribute to the complexity: the firing rate and the internal structure of the spike train. However, calculations with randomly shuffled surrogates of the original data sets showed that the complexity is not completely determined by the firing rate. The sequence-sensitive structure of the spike train is a significant contributor. By combining complexity measurements with statistically related surrogate data sets, it is possible to classify neurons according to the dynamical structure of their spike trains. This classification could not have been made on the basis of conventional distribution-determined measures. Computations with more sophisticated kinds of surrogate data show that the structure observed using complexity measures cannot be attributed to linearly correlated noise or to linearly correlated noise transformed by a static monotonic nonlinearity. The patterns in spike trains appear to reflect genuine nonlinear structure. The limitations of these results are also discussed. The results presented in this article do not, of themselves, establish the presence of a fine-structure encoding of neural information.

Algorithms↗
PubMed1994

Nonradioactive screening of glucokinase mutations in maturity onset diabetes of the young.

DNA mutations were previously identified in the glucokinase gene in 56% of French families affected with maturity onset diabetes of the young (MODY), an early onset autosomal dominant form of non-insulin-dependent diabetes mellitus (NIDDM). Mutations were found on almost all exons using the common radioactive single-strand conformation polymorphism (SSCP) technique. In this paper, we describe a non-isotopic SSCP method using the Pharmacia Biotech PhastSystem for the routine screening of new mutations in diabetic patients or in offsprings of diabetic patients. The use of the PhastSystem allowed us to easily and reproducibly optimize the electrophoretic conditions for each exon. We demonstrate the efficiency of this technique by identifying 8 mutations, 7 of which have never previously been detected, in patients referred to us for diagnostic purposes. It appears to be a sensible, easy and reliable method to improve the routine diagnosis of MODY in diabetic subjects or relatives and should be applicable to other genetic diseases.

DNA Mutational Analysis↗
PubMed1994

Polonium metabolism in adult female baboons.

The biokinetics of polonium in nonhuman primates (Papio anubis) has been studied after intravenous injection of 210Po citrate. The urinary excretion of polonium in the baboon could be described by a single exponential function with a half-time of 15.6 days. Excretion fractions of polonium were found to be markedly different from those reported for other species, including humans. Polonium-210 was found to be distributed throughout the soft tissues of the baboon with 29% of the injected polonium being deposited in liver, 7% in kidneys and 0.6% in spleen. Retention of polonium in all tissues exhibited single exponential functions; however, the biological half-times were variable, ranging from 15 to 50 days.

Animals↗