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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
PubMed1986

Sodium fluoride: effectiveness of treatment for cochlear otosclerosis.

We examined the effectiveness of sodium fluoride in treatment of cochlear otospongiosis in ninety-four patients with cochlear otosclerosis and ninety-eight patients with stapedial otosclerosis and sensorineural hearing loss. The drug halted or slowed the progression of sensorineural hearing impairment in 63% of the patients with cochlear otosclerosis and 46% of the patients with stapedial otosclerosis. The single factor that best predicted which patients would respond most favorably to treatment was rate of progression before treatment. Sodium fluoride therapy was successful for 79% of the patients losing their hearing at a rate of 5 dB or more per year at one or more of the speech frequencies. The finding that patients with more rapid rates of progression responded most favorably to sodium fluoride therapy suggests that patients with the most active otospongiotic processes will be the most responsive to treatment.

Cochlea↗
PubMed1985

Brain-derived acidic fibroblast growth factor: complete amino acid sequence and homologies.

Bovine brain-derived acidic fibroblast growth factor (aFGF) is a protein mitogen originally identified in partially purified preparations of whole brain. The protein was purified to homogeneity and shown to be a potent vascular endothelial cell mitogen in culture and angiogenic substance in vivo. The homology of aFGF to human interleukin-1 beta was inferred from partial sequence data. The complete amino acid sequence of aFGF has now been determined and observed to be similar to both basic FGF and interleukin-1's. A neuropeptide-like sequence, flanked by basic dipeptides, was observed within the aFGF sequence.

Amino Acid Sequence↗
PubMed1985

Amino acid sequence analysis of human interleukin 1 (IL-1). Evidence for biochemically distinct forms of IL-1.

The pI-6.8 species of normal human interleukin 1 (IL-1) has been isolated by ion-exchange and reverse-phase high-performance liquid chromatography. The isolated material had a molecular weight of 18,000, and had a specific bioactivity of 1.7 X 10(7) half-maximal U/mg in the murine thymocyte proliferation assay, values similar to those obtained for murine P388D1-derived IL-1 (12), and human IL-1 isolated by a previously published purification protocol (15). Amino-terminal sequence analysis revealed a single N-terminal, and resulted in the identification of 30 of the first 35 amino acid residues. Sequence of three CNBr cleavage fragments of purified IL-1 resulted in the identification of an additional 38 residues. All of the sequences agree exactly with those deduced from complementary DNA (cDNA) by Auron, et al. (18), demonstrating that this cloned cDNA, though considerably different from the cDNA reported for murine IL-1 (12), nevertheless codes for the pI-6.8 species of human IL-1. The evidence also shows that the precursor protein for human IL-1 is largely processed at the N-terminal end. Little or no processing occurs at the carboxy-terminal end. Sequence homology with interferon-inducing factor (26) suggests that the pI-6.8 species of human IL-1 is a member of a gene family. Although equally potent in the murine thymocyte proliferation assay, murine IL-1 and the pI-6.8 species of human IL-1 are structurally distinct. Further study will answer the interesting question as to the relationship of the other charged species of human IL-1 to these distinct IL-1 classes.

Amino Acid Sequence↗
PubMed1985

Depletion of adrenal catecholamines alters the amnestic effect of amygdala stimulation.

Amygdala stimulation produces a robust retrograde amnesia which appears to be related to peripheral hormonal responses to stress. This present study investigated the effects of electrical stimulation of the amygdala delivered immediately after inhibitory and active avoidance training to rats depleted of adrenal catecholamines or sham adrenal operated rats. Comparable findings were obtained with the two training tasks: amygdala stimulation impaired retention of sham adrenal operated rats but it enhanced retention of rats depleted of adrenal catecholamines. These findings suggest that adrenal catecholamines released during a training situation modulate the effects of amygdala stimulation on memory.

Adrenal Medulla↗
PubMed1985

Peripheral epinephrine modulates the effects of post-training amygdala stimulation on memory.

The present study investigated the role of adrenal epinephrine in the memory modulatory effects of post-training amygdala stimulation. Adrenal demedullated (ADMX) or sham demedullated (SHAM) rats received electrical stimulation of the amygdala immediately after training on inhibitory and active avoidance tasks. With both tasks, the stimulation impaired retention only in the rats with intact adrenal medullae: the retention performance of the ADMX in the rats with intact adrenal medullae: the retention performance of the ADMX rats given post-training stimulation was better than that of the unstimulated ADMX group with implanted electrodes. However, ADMX rats given post-training epinephrine (1.0 mg/kg, s.c.) immediately before the amygdala stimulation had retention deficits comparable to those of the SHAM group given amygdala stimulation. If epinephrine was administered a short time after rather than before the post-training amygdala stimulation, retention of the ADMX animals was not impaired. The findings are interpreted as indicating that circulating epinephrine present at the time of amygdala stimulation modulates the effects of amygdala stimulation on memory.

Adrenal Medulla↗
PubMed1985

Pure brain-derived acidic fibroblast growth factor is a potent angiogenic vascular endothelial cell mitogen with sequence homology to interleukin 1.

Pure bovine brain-derived acidic fibroblast growth factor is a very potent mitogen for vascular endothelial cells in culture and, in the presence of heparin, induces blood vessel growth in vivo. Partial amino acid sequence determinations confirm that this mitogen is a unique protein having amino acid sequence homology with human interleukin 1.

Amino Acid Sequence↗
PubMed1985

A postnatal change in the immunological properties of the acetylcholine receptor at rat muscle endplates.

We have used a myasthenic serum that in adult rat muscle is specific for acetylcholine receptors (AChRs) in the extra-junctional membrane to characterize the AChRs at developing endplates. Immunocytochemical experiments show that AChRs at endplates in the rat diaphragm bind the myasthenic antibodies during the first week after birth but lose their reactivity during the second and third postnatal weeks. AChRs at endplates in adult rat diaphragm do not bind the antibodies even after denervation; in contrast, AChRs at endplates in an adult chicken muscle (anterior latissimus dorsi) are recognized by the antibodies. The loss of immunological reactivity thus may be correlated with a change in the channel properties of the AChR and with the appearance of synaptic folds, two postnatal developmental changes that occur at the endplates of rats, but not of chickens.

Animals↗
PubMed1984

Cancer in a factory using amosite asbestos.

The paper describes the mortality experience of 5969 men employed in a factory where insulation board was manufactured using amosite asbestos from 1947 to 1979. 422 (7%) of the men were known to have died by the end of 1980. Among the 4820 men engaged in the manufacture of insulation board a doubling of the risk of lung cancer has occurred (57 deaths observed; 29 deaths expected). An excess is present both in men who entered the factory before and after 1960. Among the 2461 for whom smoking information is available a detectable excess risk is limited to current smokers exposed to higher levels of asbestos. Apart from five deaths from mesothelioma no statistically large or significant excesses of mortality from cancers of other sites have occurred, but further follow-up of the cohort is in progress. Nine deaths from asbestosis have been recorded. The results are discussed in the light of other studies of the effects of exposure to amosite asbestos.

Adult↗
PubMed1984

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↗
PubMed1983

A model solution.

Explore the source record for details and available documents.

Mental Health Services↗
PubMed1983

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↗