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Biomedical subjects

M Cohen

Publications and source records attributed to M Cohen.

At least 1,153 records · Page 64Linked to original sources
PubMedDate not supplied

Pharmacology of bumetanide.

The diuretic action of bumetanide was compared with that of furosemide following oral and intravenous administration of equipotent doses in the rat, mouse, cat, rabbit, and dog. The onset of the bumetanide-induced diuresis was rapid and lasted 4 to 6 hours. In studies of selective renal uptake, the ratio of tissue concentration to plasma concentration of bumetanide was three times greater than that of furosemide. Protein binding and metabolism studies did not reveal significant differences between the two diuretics. Bumetanide and Furosemide were excreted in dog urine as unchanged drug. Data obtained by various procedures to determine renal sites of action indicate a direct action of bumetanide at the ascending limb of Henle's loop and the proximal convoluted tubule. The altered blood flow induced by bumetanide does not per se account for the natriuretic response, but the increase in renal electrolyte excretion is thought to be linked to a prostaglandin--reninbradykinin system.

Animals↗
PubMedDate not supplied

Ultrasound-guided testicular sperm aspiration in azoospermic patients: a new sperm retrieval method for intracytoplasmic sperm injection.

PURPOSE: We investigated the technique of ultrasound-guided testicular sperm aspiration (USTSA) and compared it with "blind" testicular sperm aspiration (TSA) in patients with nonobstructive azoospermia. METHODS: Thirty-nine consecutive azoospermic men underwent TSA, 16 under sonographic guidance (USTSA group) and 23 with no imaging guidance (TSA group). Clinical and hormonal evaluation and sonography of the scrotum and testes were performed 1-2 days before the procedure. The aspiration was done using short-term general anesthesia. Follow-up consisted of sonographic reexamination of the scrotum and testes immediately and 1 month after the procedure. RESULTS: Intraoperative sonography with power Doppler imaging enabled good visualization of the testicular parenchyma, easy sampling, and avoidance of prominent vessels. Sufficient material was retrieved in 15 USTSA patients (94%) and 19 TSA patients (83%). No patients needed more than 4 hours' ambulatory hospitalization after the procedure. In the remaining 5 patients, aspiration failed to yield sperm, so open biopsy was performed. In those patients, postaspiration surgical exploration revealed subtunical bleeding in 3 patients after TSA but none after USTSA. Late minor complications occurred in 2 patients (13%) in the USTSA group and 7 (30%) in the TSA group. No difference was found between the 2 groups in pregnancy rate in the patients' female partners. CONCLUSIONS: USTSA is a safe and accurate method for sperm retrieval in azoospermic patients.

Adult↗
PubMedDate not supplied

MR perfusion imaging of the kidney pre- and post-dipyridamole stress.

Animal studies have demonstrated that renal MR contrast enhancement depends on the timing of image acquisition. Limited human studies have demonstrated effects of dipyridamole (DP) on total renal perfusion. This study assessed the effect of DP on total and regional renal perfusion using gated perfusion MRI for patients undergoing DP stress. Five subjects with no evidence of renal ischemia were examined at rest and after DP stress. Rest MRI images in the left kidney were acquired using electrocardiogram (ECG)-gated MR: turbo fast low-angle shot (FLASH); echo time (TE) = 12, repetition time (TR) = 6, flip angle = 12, inversion time (TI) = 100) 10 to 45 seconds after injection of gadopentetate dimeglumine. Stress was induced in the MRI scanner (DP, .56 mg/kg over 4 minutes) followed by stress MRI after a second bolus of gadopentetate dimeglumine in the same position and identical time intervals. MR signal in the whole left kidney and renal medulla and cortex pre- and post-DP demonstrated a 70% depression of total renal perfusion with relative preservation of cortical perfusion at the expense of medullary perfusion. Post-DP MR images demonstrated a decrease in cortical perfusion with an additional 29% depression of medullary perfusion (P < .001) with respect to cortical perfusion. Turbo FLASH MRI can provide adequate time and spatial resolution to demonstrate changes in renal perfusion. Depression of renal medullary perfusion after DP appears to be caused by the intrarenal effect of DP and may have clinical impact.

Aged↗
PubMedDate not supplied

In vitro and in vivo effects of photodynamic therapy on murine malignant melanoma.

BACKGROUND: The role of photodynamic therapy (PDT) in the treatment of malignant melanoma is not well defined, nor is it known whether the dark melanoma cells absorb the light used in PDT. METHODS IN VITRO STUDIES: 2 x 10(5) B16 murine melanoma cells were incubated with aluminum phthalocyanine (AlpcS4, 2.5 mg/kg) and were then subjected to photoradiation (50, 100 or 200 J/cm2). Viability was then assessed. In vivo studies: HISTOLOGY: C57/B1 mice received 2 x 10(5) B16 cells subcutaneously and were randomized into study (PDT) and three control groups. AlpcS4 2.5 mg/kg was injected intraperitoneally and the mice were exposed to light (100 J/cm2). After 24 hours they were sacrificed and underwent autopsies. Survival: 40 mice were randomized into PDT (40 J/cm2) and control groups and were monitored for 50 days. Tumor growth: 40 mice were randomized into one control and three treatment groups (PDT on day 3, 6, or 12 after injection with B16 cells), and were monitored for 50 days. Temperature: Tumor temperatures before and at the end of PDT were recorded. RESULTS IN VITRO STUDIES: PDT caused a decrease in cell viability to 15.5 +/- 0.7%, 11.5 +/- 2.1%, and 1.5 +/- 0.7% (at 50, 100, and 200 J/cm2, respectively; P < .001). A significant reduction in thymidine incorporation was noted at all energy levels. In vivo studies: HISTOLOGY: PDT caused massive tumor necrosis. Survival: PDT prolonged the survival of mice (41 +/- 13.4 days) compared to controls (15.8 +/- 3.8 days, P < .001). Tumor growth: 31 days after injection with B16 cells, the tumor size was 2.6 +/- 0.3 cm in the control group and 1.6 +/- 0.2, 0.9 +/- 0.3, and 1.0 +/- 0.4 cm in the PDT groups (days 3, 6 and 12, respectively; P < .01). Temperature: PDT increased skin temperature to 42.8 degrees C +/- 1.3 degrees C, 45.3 degrees C +/- 3.5 degrees C, and 51.7 degrees C +/- 2.7 degrees C at 40, 60, and 100 J/cm2, respectively (P < .01). CONCLUSIONS: Photodynamic therapy was found to have significant effects in experimental melanoma in mice. The role of PDT in human melanoma remains to be studied.

Animals↗
PubMedDate not supplied

Pharmacokinetics of mirtazapine from orally administered tablets: influence of a high-fat meal.

The effect of a high-fat meal on the pharmacokinetics of mirtazapine was studied in 19 healthy normal young male volunteers. In a randomized two-period crossover study, each volunteer received an oral dose of 15 mg of mirtazapine in the form of tablets, in the fasting state and after a high-fat meal, with a washout period of 14 days between the two doses. Serial blood samples were taken and pharmacokinetic parameters calculated and statistically analyzed from mirtazapine plasma levels. The extent of absorption of mirtazapine, as measured by the area under the plasma level versus time curve, was found to be equivalent for the fasting and the fed state. Food intake was shown to have no influence on the elimination of mirtazapine, as measured by its elimination half-life. The rate of mirtazapine absorption, as measured by the peak level (Cmax), was not altered by food. The peak time (tmax), however, in subjects in the fed state showed an increase: the 90%-confidence interval for the median difference ranged from 0.25 to 1.25 h. This was the only effect of food found in this study. It is considered to be of no clinical consequence.

Absorption↗
PubMedDate not supplied

Adnexal-centered giant congenital melanocyte nevus with extensive ganglioneuromatous component and trisomy 7.

Adequate interpretation of clinical and histopathologic features of giant congenital melanocytic nevus (GCMN) in newborns is a continued challenge. A GCMN with three large nodules and three polypoid exophytic tumors presented in the dorsum of a female full-term newborn, the borders exhibiting a spotted grouped pattern. Microscopic examination revealed a peculiar adnexal-centered (eccrine sweat gland ducts, acrosiringia, and hair infundibula) compound nevus expressing pagetoid intraepidermal spreading of epithelioid melanocytes. The nodules represented an extensive ganglioneuromatous component. The neurons and their neuropil were positive for neuron-specific enolase, S-100, synaptophysin, tyrosine hydroxilase, and PGP 9.5. In addition to these components, a poorly differentiated, fusiform, low-mitotic rate population of cells undergoing epithelioid differentiation (and probably neuronal differentiation) with nodular arrangement was also present in the polypoid tumors and deeper parts of the nevus, in part intermixed with the neurons. These cells were vimentin positive but S-100 negative. FISH studies revealed these cells to express three signals for the centromeric probe for chromosome 7 whereas the neuronal component showed just two. Adnexal-centered arrangement of melanocytes has not been emphasized in GCMN. Ganglioneuromatous differentiation has been rarely reported in this condition. Trisomy 7 in GCMN has been reported only once previously.

Chromosomes, Human, Pair 7↗
PubMedDate not supplied

Acute and longer term effects of meso-2,3 dimercaptosuccinic acid (DMSA) on the behavior of lead-exposed and control mice.

We investigated the effect of chelating agent meso-2,3 dimercaptosuccinic acid (DMSA) on spatial learning and forced-swim immobility in Binghamton Heterogeneous Stock (HET) mice. Forced-swim immobility (characterized by increasingly frequent bouts of complete motionlessness in a forced-swim test, i.e., behavioral despair) is reduced by exposure to lead. In Experiment 1, male and female HETs (n = 81) were assigned to lead-exposed (0.5% lead acetate ad lib in drinking fluid), pair-fed (PF), or water control groups. Six weeks after the termination of lead exposure, half of each group was injected intraperitoneally (IP) with 50 mg/kg DMSA or vehicle once per day for 5 days. Following treatment, all animals were tested for acquisition and extinction in the Morris Water maze, followed by immobility testing in an inescapable forced-swim task. Neither Pb nor DMSA affected Morris maze performance. However, consistent with previously published work, Pb reduced immobility in the forced-water swim relative to both PF and water controls. Additionally, lead-exposed males, but not females, showed sustained improvement following DMSA treatment on immobility measures. Experiment 2 was designed to demonstrate the effect of the above DMSA protocol on blood-Pb, and also examined the immediate effects of DMSA on immobility during treatment. Thus, in Experiment 2, animals were exposed to an identical Pb and DMSA treatment protocol, but the effects of DMSA on immobility during the course of DMSA treatment were measured, and animals were sacrificed immediately after treatment so that blood-Pb measures could be taken. Under these circumstances, DMSA markedly reversed the lead-induced reduction in immobility immediately during the treatment phase. Although DMSA clearly reduced blood-lead in males, its influence on female blood levels was far less. Taken together, the data from these experiments suggest that DMSA ameliorates lead-induced immobility changes in mice, but that gender may modulate DMSA's effect on blood-lead and longer-term behavioral effects. However, further work is needed to clarify the role of gender in response to DMSA.

Animals↗
PubMedDate not supplied

Minimizing the pain of local infiltration anesthesia for wounds by injection into the wound edges.

This study on low contamination wounds was conducted to compare the pain of local infiltration anaesthesia administered into the skin surrounding the wound with administration directly into the incised edges of the wound. Eighty-one adult patients were randomized by date of presentation to receive infiltration anesthesia by one of the two methods. Pain of anesthetic administration was rated on a visual analogue scale and recorded as a pain score in millimeters. The results demonstrated that the average pain score for infiltration into the wound was significantly lower than the average pain score for infiltration into skin surrounding the wound.

Adult↗