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Biomedical subjects

C Bennett

Publications and source records attributed to C Bennett.

At least 109 records · Page 6Linked to original sources

Insulin release pattern after blockade of catecholamine synthesis with alpha-methyl tyrosine in vivo.

Insulin release pattern in vivo was studied using 30 control rats and 30 rats treated with alpha-methyl tyrosine to block catecholamine synthesis in vivo four days before the time of investigation. The drug treated animals exhibited significantly higher fasting insulin levels, and also the first phase insulin release after the B cell was challenged with a glucose load was significantly higher in these animals than occurred in the controls. This observation implies that the B cell is modulated by the sympathetic nervous system in its function and the insulin release would vary according to the emotional state of the individual.

Animals↗

A model solution.

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Mental Health Services↗

4-OH amphetamine enhances retention of an active avoidance response in rats and decreases regional brain concentrations of norepinephrine and dopamine.

An .82 mg/kg dose of dl-4-OH amphetamine administered ip immediately following training in a one-way active avoidance task enhanced retention performance measured 24 hr later. In contrast, 4-OH amphetamine in a dose range of .41--1.65 mg/kg ip did not affect retention of a swim escape task. The behaviorally active dose of .82 mg/kg 4-OH amphetamine decreased dopamine concentrations in the amygdala and hippocampus. A dose of 8.2 mg/kg 4-OH amphetamine administered ip to naive untrained rats decreased concentrations of norepinephrine measured in the amygdala, cortex, hippocampus, hypothalamus, and midbrain; decreased concentrations of dopamine in the amygdala, cortex, hippocampus, and striatum; and significantly reduced concentrations of norepinephrine and epinephrine in the adrenal medulla. In addition, because the integrity of the adrenal medulla is necessary for the enhancing action of 4-OH amphetamine and because 4-OH amphetamine reduces concentrations of catecholamines in the brain and adrenal medulla, it is possible that 4-OH amphetamine affects retention performance by a dual action on the brain and the adrenal medulla.

Adrenal Medulla↗

Further characterization of a melanoma-specific protein from human urine.

Isolation of a melanoma-specific protein (MSP) from human urine has been achieved using antibody affinity chromatography. MSP migrates as a single homogeneous protein on SDS PAGE and comparison of these data and ultracentrifuge analyses indicates that MSP contains a single polypeptide chain. MSP, however, shows considerable charge heterogeneity on isoelectric focusing. The desialo form, alpha 2 MSP, is found predominantly in patients with advanced metastatic disease, whilst only the sialo form alpha 1 MSP, is obtained from the urine of patients with early-stage disease. MSP does not react with antisera raised to alpha 1 foetoprotein (AFP) or carcinoembryonic antigen (CEA) and hence is immunologically distinct from these other tumour-associated glycoproteins. Antisera raised to MSP do not react with normal skin melanocytes nor with any foetal tissue tested, and hence the origin of MSP remains unresolved.

Antibody Specificity↗

Melanocyte mutation in halo naevus and malignant melanoma?

Halo naevus cells on frozen sections react with sera from patients with benign halo naevus or with malignant melanoma. Halo naevus cells also react with our specifically absorbed heterologous antihuman malignant melanoma antiserum (RAMMA). Since the cytoplasm of all the naevus cells within the halo naevus react with sera from patients with malignant melanoma, this implies that the entire population of melanocytic cells in the mole has undergone mutation, because non-pathological skin melanocytes do not react.

Adult↗

Melanoma specific protein: occurrence in the urine of patients with halo naevus and vitiligo.

Melanoma specific protein is immunologically related to altered naevus cell cytoplasm. It is excreted by patients with malignant melanoma but in no other malignancy. The protein has been detected in patients with actively developing halo naevi but not when repigmentation is taking place. It also occurs in patients with very active vitiligo but in no other pigment condition we have studied. It is suggested that the protein is a marker of active destruction of naevus cells by immune mechanisms and that the release of toxic materials during this immune reaction may be responsible for the production of the halo phenomenon and for the areas of vitiligo that may be seen elsewhere on the skin.

Adolescent↗

The significance of urinary melanoma antigen excretion and the ability of thymosin to raise the level of depleted lymphocytes in vitro in malignant melanoma.

One hundred and fifty-six patients were screened for the presence of urinary melanoma antigen and serum cytoplasmic antibody. It was found that 44% of symptomless Stage 1 patients tested five to 15 years after operation had detectable antigen (Ag) in their urine; the urines of 67% of Stage 2A (local recurrence) patients were positive for Ag; while in only 38% of those patients graded 2B (lymph-node involvement) were these tests positive. Urines of 83% of patients with generalized metastases (Stage 3) were positive. A sequential study was made of 23 patients seen and treated in 1976. Of this group, 14 reverted from a positive state to a negative one following excision of their tumour, while six were negative on first postoperative testing and subsequently became positive. Three out of the 23 remained persistently negative. T lymphocyte levels were assessed in 71 melanoma patients, and a stage-related fall was noticed. Thymosin (Hoffman LaRoche) on in vitro incubation significantly raised the levels of T lymphocytes.

Adult↗

Predictors of drinking and signs of heavy drinking among high school students.

This paper reports an investigation of factors associated with drinking and heavy drinking among high school students. The relative importance of social characteristics, parental drinking and parental rejection and control are assessed. Data were obtained from 1,439 students in two high schools. It is found that most students drink, but most drink infrequently (less than once a week and one or two drinks at time). Multivariate analysis using the MCA program indicates that students who frequently get drunk are those who are heavy drinkers, drink away from home and in cars, and whose drinking is not known to their parents. Parents' drinking and parental rejection and control have little unique explanatory power. It is suggested that parental modeling may be of most importance at the outset of drinking, whereas place and extent of drinking is most important in predicting the signs of heavy drinking.

Adolescent↗

The implantation of natural tooth form bioglasses in baboons. A preliminary report.

This report describes a 6-month screening study comparing the tissue responses of several bioglass natural tooth implants in adult female baboons. The dental implants were designed to elicit osteogenesis at the interface of the implant and the oral tissues. This is in contrast to those types of implant materials that are merely biologically acceptable. Incisor teeth were extracted, dupplicated in bioglass, returned to the natural sockets, and splinted to the adjacent natural tooth, where they remained splinted for 3 months and then free standing for an additional 3 months. Microscopic evaluation revealed distinct histopathologic characteristics with certain bioglass formulas, such as ankylosis, a pseudofibrous capsule with fibers running parallel to the root surface, or an apparently true periodontal membrane with properly oriented Sharpey's fibers. True cementogenesis was not found.

Animals↗

Segmental renal hypoplasia and hypertension.

The association of hypertension with congenital renal hypoplasia (Ask-Upmark kidney) has been well established. A case is presented that clearly demonstrates the distinctive clinical, roentgenographic and pathologic features. An abnormal production of renin by the affected kidney suggested that the renin-angiotensin-aldosterone axis was involved in the genesis of the hypertension. Hypertension was cured by unilateral nephrectomy.

Aortography↗