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Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 19 recordsLinked to original sources
PubMed1992

Physical aspects of the EEG in schizophrenics.

Physical and dynamic aspects of the electroencephalogram (EEG) were evaluated in 12 schizophrenic patients and 12 matched healthy control subjects by means of two descriptive measures proposed by Hjorth (complexity and mobility) and by a nonlinear measure, dimensional complexity. These measures were compared to power spectra analyses. EEG was recorded from frontal, central, and parietal leads under resting conditions (eyes open and eyes closed) for 12 epochs each of 25 sec. Patients showed the expected increased activity in the 1-7 Hz band and, furthermore, a scalp distribution of dimensional complexity and Hjorth complexity opposite to the distribution in controls: in patients dimensional complexity yielded higher values at frontal (Fz) than central (Cz) leads, whereas the resemblance to sinusoidal waveshape (Hjorth complexity) was larger at Fz than Cz. Results indicate more dynamic complexity or variables determining the dynamics of brain processes in frontal areas in patients.

Adult↗
PubMed1992

Tarsal lameness of dairy bulls housed at two artificial insemination centers: 24 cases (1975-1987).

Degenerative joint disease of the tarsi was diagnosed in 20 of 24 Holstein bulls with tarsal lameness at 2 artificial insemination centers from 1975 to 1987. Each of the 2 centers housed about 100 bulls/yr. Of the 24 bulls with tarsal lameness, 22 were from the artificial insemination center designated as A, and 2 were from the center designated as B. Examination of the housing and management procedures revealed that center A had concrete floors with cuboidal-shaped yards, whereas center B had deep sand flooring, with long, narrow yards. The only other difference between the 2 centers was that center A used 1- and 2-year-old bulls as teasers for older, heavier bulls to mount, whereas center B used bulls that were at least 6 years old to withstand the stress placed on their hind limbs by the weight of bulls undergoing semen collection. Radiographic lesions of tarsi of bulls from both centers ranged from distention of the tibiotarsal joint pouch to hypertrophic degenerative osteoarthritis of the distal, intertarsal, and tarsometatarsal joints. It was concluded that the concrete flooring and the semen collecting practices were responsible for the high prevalence of tarsal lameness and degenerative joint disease of the tarsi in bulls housed at center A.

Animals↗
PubMed1992

CCP II: a novel calcitonin carboxy terminal peptide is expressed in normal thyroid tissue.

We have recently identified in medullary thyroid carcinoma the existence of a second calcitonin messenger, generated by a splicing between the 3' coding region of exon 4 and exon 5 of Calc I gene. It differs from the first one in its 3' coding sequence and codes for a calcitonin precursor which generates the same N terminal peptide, calcitonin and a specific 21 amino acid carboxy terminal peptide differing from Katacalcin by its 8 last amino acids. We searched for the expression of this new messenger in normal human thyroid tissue by Northern and by polymerase chain reaction techniques. This second calcitonin messenger was expressed in 4/4 normal thyroids and 4/5 medullary thyroid carcinoma tissue samples. The expression of this second messenger is apparently a common occurrence in C cells whether normal or tumoral.

Amino Acid Sequence↗
PubMed1992

[Prevention of acute otitis media. Amoxicillin versus glycoproteins from Klebsiella pneumoniae. Study in children under 5 years of age].

Several studies in the English language literature have shown that continuous antibiotic prophylaxis is more effective than a placebo in preventing recurrent otitis media. In this prospective, randomized trial the effectiveness of continuous amoxicillin therapy was compared with that of glycoproteins from Klebsiella pneumoniae (GKP). The two treatments were administered during 3 months to children aged 1 to 5 years, who had at least 3 episodes of otitis media within the 3 months preceding their admission to the trial. The trial lasted from February 1989 to July 1990. It involved 60 children (mean age: 22.6 months) who had been seen as out-patients and had recovered from their latest episode of otitis. Thirty-three children received amoxicillin 25 mg/kg/day divided into two doses, during 3 months. Twenty-seven children were given GKP 2 tablets per day during 8 days in the 1st month and 1 tablets per day during 8 days in the following 2 months. During the study period, 14 cases of otitis media were observed in children under amoxicillin, as against 22 cases in children under GKP. When the type of day-nursery was taken into account as adjustment factor, the results showed a significantly lower percentage of failures in the amoxicillin group (P less than 0.03). Both treatments were well tolerated (no child was excluded from the trial for intolerance). No Clostridium difficile toxin developed in the amoxicillin group.

Acute Disease↗
PubMed1992

Liposomes as a model for the study of the mechanism of fish toxicity of sodium dodecyl sulfate in sea water.

The mechanism underlying the shark repellency of SDS was studied by comparing it with the shark nonrepelling detergent, Triton X-100. The findings can be summarized as follows: (1) The effective concentration of SDS for termination of shark tonic immobility (an immediate and fast response) was close to its critical micellar concentration in sea water (70 microM). The fish lethal concentrations (LD50) were far below the CMC value for SDS, and at CMC level for Triton X-100. (2) In sea water SDS possesses a strong affinity for lipid membranes, expressed in a lipid sea water partition coefficient (Kp) of about 3000. (3) In liposomal systems examined by assays of turbidity, fluorescence resonance energy transfer and kinetics of carboxyfluorescein (CF) release, the pattern of SDS induced changes in the phospholipid bilayer suggests: (a) absence of vesicle-vesicle fusion; (b) occurrence of vesicle size increase, and (c) nonlytic gradual release of CF above and below its CMC values. In contrast, Triton X-100 above its CMC induces membrane solubilization. (4) Assays coupling CF release from liposomes to potassium diffusion potential induced by valinomycin indicate that SDS related CF release can also be attributed to a specific mechanism such as cation pore formation and not only to membrane solubilization. The hypothesis of pore formation by SDS is discussed.

Animals↗
PubMed1992

Prediction of relapse of schizophrenic patients: Camberwell Family Interview versus content analysis of verbal behavior.

In a replication of the study by Gottschalk et al. (1988), expressed emotion scores derived from the Camberwell Family Interview were compared with Anxiety and Overt Hostility Outward scores from a content analysis of verbal behavior based on a 10-minute speech sample from parents of 49 German schizophrenic inpatients. The scores from the two methods were significantly correlated, but only expressed emotion scores predicted relapse during a 12-month followup. Scores from the Gottschalk-Gleser content analysis did not exceed chance level in prediction of relapse.

Adult↗
PubMed1992

Effects of octreotide on lipid metabolism in acromegaly.

Hypertriglyceridemia is the most frequent modification of lipid metabolism observed in acromegaly. The somatostatin analog, octreotide (Sandostatin), widely used in the treatment of acromegaly, is able to produce a decrease in levels of growth hormone (GH), insulin, and Insulin-like Growth Factor 1 (IGF1). We have attempted to evaluate the influence of this treatment on the lipid status of acromegalic patients. Seventeen patients with active acromegaly were treated with octreotide, 100 to 500 micrograms/injection subcutaneously three times daily. The levels of fasting serum triglycerides (TG), total cholesterol, High Density Lipoprotein (HDL) cholesterol and IGF1, as well as mean plasma GH and insulin levels during a diurnal profile, were evaluated before and after three months of octreotide therapy. GH, insulin and IGF1 decreased by 61%, 42% and 36% respectively (p less than 0.05). Mean levels (+/- SEM) of TG and total cholesterol fell from 2.2 +/- 0.4 mmol/l to 1.6 +/- 0.3 mmol/l (p less than 0.05) and 6.4 +/- 0.39 mmol/l to 5.6 +/- 0.27 mmol/l (p greater than 0.05), respectively. There was no correlation between triglyceride decrease and hormonal changes or clinical status (BMI, age, sex). In conclusion, the administration of octreotide over a three month period to acromegalic patients is associated with a decrease in TG levels.

Acromegaly↗
PubMed1992

In-vitro antibacterial activity of RP 59500, a semisynthetic streptogramin, against Streptococcus pneumoniae.

The in-vitro activity of the new streptogramin RP 59500 was determined against 100 strains of Streptococcus pneumoniae. In all, 48 erythromycin-sensitive strains and 52 erythromycin-resistant strains were tested by an agar dilution method (MIC determination), 20 strains (eight erythromycin-sensitive and 12 erythromycin-resistant) were tested by a broth microdilution technique (MIC and MBC determination) and ten strains (two erythromycin-sensitive and eight erythromycin-resistant) were tested for bactericidal kinetics. The study showed that RP 59500 had good bacteristatic and bactericidal activity against both erythromycin-sensitive and erythromycin-resistant strains. On the basis of these results, and because the number of erythromycin-resistant strains of S. pneumoniae isolated in France has increased steadily since 1985, RP 59500 might be useful for the treatment of pneumococcal infections and warrants further investigation.

Erythromycin↗
PubMed1992

Results of long-term continuous subcutaneous octreotide administration in 14 patients with medullary thyroid carcinoma.

OBJECTIVE: Treatment by octreotide has been suggested in medullary thyroid carcinoma patients with post-surgery metastases. The purpose of this study was to evaluate if the tumoral regression could be improved by a high dose and by prolonged octreotide treatment. DESIGN: Fourteen thyroidectomized patients were studied. All patients had persistently elevated plasma calcitonin levels with normal or elevated carcino-embryonic antigen levels. Five hundred micrograms/day of octreotide were administered by continuous subcutaneous infusion for 90 days. MEASUREMENTS: Plasma calcitonin and carcino-embryonic antigen levels were determined at days -30, -20, -2, -1, 0, +30, +60, +90, +120; morphological extension was evaluated every month. RESULTS: Continuous infusion of octreotide did not induce any significant decrease of calcitonin levels, or any morphological improvement, and had no major undesirable effect. However, in 4/14 patients calcitonin levels fell during treatment (-43, -50, -15, -20%), and in 9 patients calcitonin increased (+22 to +130%) after cessation of therapy. CONCLUSION: Biological or morphological parameters of medullary thyroid carcinoma are not significantly improved in a large series of patients treated by octreotide.

Adult↗
PubMed1992

Bowel infarction as the initial manifestation of disseminated aspergillosis.

Disseminated aspergillosis in the immunocompromised patient most commonly presents with clinically apparent pulmonary involvement and roentgenographic infiltrates. We report a patient with acute myelogenous leukemia who developed bowel infarction due to gastrointestinal invasion of Aspergillus fumigatus as the initial manifestation of widespread fungal disease.

Adult↗
PubMed1992

Glucose homeostasis. Comparison between hypothermic and normothermic cardiopulmonary bypass.

STUDY OBJECTIVE: Disturbance in blood glucose homeostasis during cardiac surgery may cause visceral and metabolic alterations. Hypothermic CPB induces glucose and hormonal changes. As normothermic CPB is used at some institutions, a comparison of blood glucose and plasma hormones between hypothermic and normothermic CPB was performed. DESIGN: Prospective nonrandomized study. SETTING: University cardiac center. PATIENTS: Twenty-two nondiabetic adults undergoing elective coronary bypass and/or valvular surgery. INTERVENTIONS: Group 1 (n = 12) underwent hypothermic CPB (25 degrees C) and group 2 (n = 10) normothermic CPB (37 degrees C). In both groups nonpulsatile CPB was achieved with a membrane oxygenator and dextrose-free crystalloid priming. Dextrose was not administered during surgery but was infused postoperatively (125 mg/kg/h). MEASUREMENTS AND RESULTS: Eight blood samples were drawn during the period of arrival in the operating room (control) to the third postoperative hour. During hypothermic CPB in group 1, blood glucose level increased to 154 +/- 20 mg/dl (mean +/- SD) associated with a decrease in plasma insulin and an increase in epinephrine, despite a decrease in cortisol and growth hormone. During rewarming, the blood glucose value continued to increase (to 197 +/- 35 mg/dl) associated with an increase in glucagon, growth hormone and catecholamines, despite a 374 percent increase in insulin. During CPB in group 2, insulin, glucagon, cortisol and catecholamines were significantly higher than during hypothermic CPB so that the blood glucose level was not significantly different between the two groups during CPB. Blood glucose value was higher in group 1 than in group 2 at closure of the chest (208 +/- 30 vs 175 +/- 19 mg/dl, respectively, p less than 0.02) and at the third postoperative hour (271 +/- 30 vs 221 +/- 51 mg/dl, p less than 0.01). In both groups, however, the postoperative increase in blood glucose was accompanied by a similar increase in insulin, cortisol and catecholamines but glucagon was lower after hypothermic CPB. CONCLUSIONS: Hyperglycemia occurred perioperatively in cardiac surgery with dextrose-free priming both during hypothermic and normothermic CPB but normothermic CPB resulted in a slow and steady increase in both glucose and insulin concentrations without the major perturbations that occurred with hypothermic CPB. Postoperatively, higher blood glucose was observed in the hypothermic CPB group.

Adult↗
PubMed1992

Giant cell tumor of the intermediate cuneiform. A case report.

Although it has yet to be determined which surgical procedure provides the least chance for recurrence, surgical treatment remains the preferred therapy for giant cell tumors of bone. Few cases of giant cell tumor of the tarsus have been reported in the literature, with less than 10 of these cases occurring in the cuneiforms. When the extent of the tumor is questionable, definitive radiologic techniques should be used to aid in the selection of the most appropriate surgical procedure. Follow-up radiographic examination is critical to ensure that the patient remains tumor free. Yearly chest x-rays are recommended to rule out pulmonary metastasis. Although giant cell tumors represent only 5% to 8% of all benign primary osseous neoplasms of the foot, they have the potential to undergo malignant transformation, increasing the morbidity and mortality to the patient. Giant cell tumors of bone are locally aggressive, often occurring adjacent to articular surfaces, and usually are large when diagnosed. It is essential for the surgeon to plan a treatment that not only minimizes the chance of recurrence, but also attempts to preserve function of the involved part.

Bone Neoplasms↗
PubMed1992

Evaluation of a biodegradable matrix containing cultured human fibroblasts as a dermal replacement beneath meshed skin grafts on athymic mice.

Meshed, expanded split-thickness skin grafts (MSTSG) frequently achieve poor results when used to cover full-thickness wounds. Poor cosmetic and functional results occur in part because the epithelium that grows across the skin graft interstices lacks a dermis. We used a living dermal replacement composed of either polyglycolic acid (PGA) or polyglactin-910 (PGL) mesh containing confluent, cultured human fibroblasts. These grafts were applied to full-thickness wounds on athymic mice; widely expanded, 3:1 ratio human MSTSG was then placed over the dermal graft. Histologic examination of wounds during a 99-day period after graft placement showed that PGA/PGL-fibroblast grafts vascularized to the wound, and the MSTSG simultaneously vascularized to the PGA/PGL-fibroblast graft. Epithelialization from the MSTSG bridges proceeded rapidly across the surface of the PGA/PGL-fibroblast grafts, resulting in an epithelialized layer that covered a densely cellular substratum that resembled dermis. Basement membrane formation at the dermal-epidermal junction of the epithelialized interstices was confirmed by immunohistochemical microscopy. Minimal inflammatory reaction to the PGA/PGL-fibroblast grafts was seen. Grafts composed of PGA or PGL biodegradable meshes combined with cultured fibroblasts vascularize in full-thickness wounds, resulting in formation of organized tissue beneath the epithelialized surface that resembles dermis.

Animals↗