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Biomedical subjects

G Hunt

Publications and source records attributed to G Hunt.

At least 19 recordsLinked to original sources
PubMed1992

The expression of functional MSH receptors on cultured human melanocytes.

Although alpha-MSH increases skin darkening in humans, there are several reports that it fails to have melanogenic effects on human melanocytes in vitro. The purpose of this study was to see whether cultured human melanocytes express MSH receptors. Human melanocytes were grown in the absence of artificial mitogens such as 12-O-tetradecanoyl phorbol-13-acetate (TPA) and cholera toxin (CT) and incubated for 2 h at room temperature with increasing amounts of 125I-labelled Nle4DPhe7-alpha-MSH with and without excess cold peptide. Binding was saturable and specific: Scatchard analysis gave a Kd of 4.9 x 10(-11) M and approximately 700 binding sites/cell. Human keratinocytes and fibroblasts showed no specific binding. The addition of 1 mM dibutyryl cAMP to the culture medium caused a 62% increase in MSH binding to human melanocytes. A smaller increase (25%) was seen with 10(-9) M CT while 25 mM TPA caused a 24% decrease. These results show that human melanocytes in culture express MSH receptors and that this expression can be modulated by mitogens.

Animals↗
PubMed1992

Evaluation of a microcarrier process for large-scale cultivation of attenuated hepatitis A.

Microcarrier culture was investigated for the propagation of attenuated hepatitis A vaccine in the anchorage-dependent human fibroblast cell line, MRC-5. Cells were cultivated at 37 degrees C for one to two weeks, while virus accumulation was performed at 32 degrees C over 21 to 28 days. The major development focus for the microcarrier process was the difference between the cell and virus growth phases. Virus antigen yields, growth kinetics, and cell layer/bead morphology were each examined and compared for both the microcarrier and stationary T-flask cultures. Overall, cell densities of 4-5 x 10(6) cells/ml at 5-10 milligrams beads were readily attained and could be maintained in the absence of infection at either 37 degrees C or 32 degrees C. Upon virus inoculation, however, substantial cell density decreases were observed as well as 2.5 to 10-fold lower per cell and per unit surface area antigen yields as compared to stationary cultures. The advantages as well as the problems presented by the microcarrier approach will be discussed.

Antigens, Viral↗
PubMed1992

Increased lymphatic pumping ability in pregnant ewes.

OBJECTIVE: Daily the lymphatic system returns several liters of fluid to the systemic circulation. Unlike blood, lymph is pumped against a pressure gradient. Because vessels in the systemic circulation are hyporesponsive to vasoconstrictor hormones during pregnancy, we decided to assess whether lymphatic pumping ability was decreased during pregnancy. STUDY DESIGN: Ten pregnant ewes were chronically catheterized in the left thoracic duct and jugular vein. Four days after surgery thoracic duct pumping ability was determined by measuring the lymph flow rate as a function of outflow pressure by varying the height at which lymph flow drains in an open-flow system. RESULTS: Lymph flow was plotted against outflow pressure, and the value at which lymph flow decreases is defined as the "breaking point." The outflow pressure at which lymph flow equals zero is the "stopflow" pressure; this value defines the pumping ability. The pregnant ewes had a breaking point of -1 +/- 2.7 versus 14.4 +/- 3.0 mm Hg (mean +/- SD) for the nonpregnant sheep. Stopflow pressures were 62 +/- 7.3 versus 23.9 +/- 4.7 mm Hg (mean +/- SD) for the nonpregnant ewes (p < 0.05). CONCLUSIONS: The ability of the lymphatic system to generate pressure is increased during pregnancy, but the breaking point is diminished. Alterations of lymphatic pumping ability could explain fluid retention under pathophysiologic conditions.

Animals↗
PubMed1992

What is nursing ethics?

This article tries to bring some clarity into the current confusion about the nature of nursing ethics. It distinguishes between the empirical, prescriptive and analytic dimensions of ethics. It then describes six contemporary understandings of the parameters and aims of ethics via six different approaches: moral education, management, professional conduct, bioethics, clinical ethics and political ethics.

Education, Nursing↗
PubMed1991

Biochemical and physiological characterization of the efrotomycin fermentation.

An efrotomycin fermentation was characterized through physical, chemical and biochemical studies. Growth of the actinomycete, Nocardia lactamdurans occurred during the first 50 h of the fermentation cycle at the expense of glucose, protein, and triglycerides. The initiation of efrotomycin biosynthesis was observed when glucose dropped to a low concentration. Upon glucose depletion, cell growth ceased and a switch in the respiratory quotient occurred. Efrotomycin biosynthesis was supported by the utilization of soybean oil and starch. Analysis of triglyceride metabolism showed that no diglycerides or monoglycerides accumulated during the fermentation. The activity of extracellular enzymes (lipase, protease, and amylase) increased during the cell growth phase and decreased significantly after 150 h. The concentrations of DNA, tetrahydro-vitamin K2 (a membrane component), and free amino acids in the supernatant increased dramatically late in the fermentation cycle (225 h), indicating massive cell lysis. During this same time period, a reduction in cellular respiratory activity and efrotomycin biosynthesis were observed.

Amino Acids↗
PubMed1990

Schizophrenia and indeterminacy: the problem of validity.

The paper attempts to account for the confusion over the validity of the concept of 'schizophrenia' in terms of two closely related aspects of conceptual indeterminacy. Firstly, it is identified on the basis of a breakdown in intelligibility, but what constitutes such a breakdown is indeterminate. Secondly, the concept sits between the categories of natural disease or illness on the one hand, and character trait or moral failing or gift on the other. This entails an indeterminacy in attempting to define the role that physiological explanation could have. Light may be thrown on the concept by exploring a distinction between a life story in which the schizophrenic condition emerges as the conclusion of the story and a causal process in which the condition is the end result or final consequence.

Humans↗
PubMed1978

Intermittent catheterisation in the management of children with neuropathic bladder.

Twenty-three children with neuropathic bladder have been treated by intermittent catheterisation during the past 3 years. Twelve are now practically dry, nine are drier than before, and two have remained wet. Urinary infections have not been a major problem, but it is too soon to assess the long-term effects on the upper renal tract. Intermittent catheterisation lightens the burden for the mothers. Four children catheterise themselves and two of them are now independent.

Adolescent↗
PubMedDate not supplied

Isolation of Aeromonas spp. from canal water.

Aeromonas sobria was identified from soil and canal water at the East End of London. There was a correlation between water and faecal isolates from children attending the nearby Children's Hospital. In view of the potential risk of enteric and non-enteric infections due to Aeromonas spp, efforts are needed to ensure that canals, rivers, natural water sources and domestic water supply are free of these organisms.

Aeromonas↗