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Biomedical subjects

M Somerville

Publications and source records attributed to M Somerville.

24 records · Page 2Linked to original sources
PubMed1989

Local anaesthesia of the trachea and mucus secretion.

We have tested whether two local anaesthetics, in the lumen of cat trachea in vivo, would block the stimulation of mucus secretion by parasympathetic nerves without altering its stimulation by a cholinergic drug. Lignocaine, 4.3-43 mM (0.1-1%) in Krebs-Henseleit, increased the output of mucus macromolecules. It abolished secretion in response to vagus nerve stimulation, but also diminished the effect of 5 microM pilocarpine. Tetrodotoxin, 50 microM, abolished vagal control of secretion without inhibiting pilocarpine's action or changing resting secretion. Though lignocaine blocks nerve-mediated secretion, its action is not simply on nerve conduction. In contrast, the effect of tetrodotoxin may be restricted to the blocking of nerves.

Anesthetics, Local↗
PubMed1985

Exchange transfusion in severe falciparum malaria.

Three cases of severe falciparum malaria with high parasitaemia, one of them complicated by disseminated intravascular coagulation, were treated with exchange transfusion in addition to conventional chemotherapy. All three made a good recovery. There are few previous reports of this treatment which deserves wider attention and further assessment.

Adult↗
PubMed1983

Comparison of the effects of heat shock and metal-ion stress on gene expression in cells undergoing myogenesis.

Subjecting 9-day-old quail embryos to an elevated temperature in ovo causes limb, breast, and brain tissues to shift their patterns of protein synthesis from the production of a broad spectrum of different proteins to the new and (or) enhanced synthesis of a small number of heat-shock proteins (HSPs). The HSPs synthesized by undifferentiated breast tissue in ovo (relative masses (Mrs) 88 000, 82 000, 64 000, and 25 000) are similar to those synthesized by explanted breast tissue or by primary cultures of breast myoblasts heat-shocked in culture. Heat-shocked, 120-hour-old myotube cultures synthesize HSPs similar to those detected in heat-shocked myoblasts except that myotubes also exhibit enhanced synthesis of a 55 000 dalton polypeptide and little or no synthesis of a 25 000 dalton HSP; the failure to thermally induce a 25 000 dalton polypeptide in myotubes is related to the fused nature of these cells rather than to their state of differentiation. Myoblasts, as well as myotubes, cultured in the presence of elevated amounts of arsenite, copper, or zinc also synthesize new and (or) enhanced amounts of polypeptides with isoelectric points and immunochemical properties similar to the 25 000 and 64 000 dalton HSPs. However, elevated levels of these metal ions fail to stimulate new and (or) enhanced synthesis of other HSP-like proteins. These results demonstrate that, although the protein synthetic response of myogenic cells to chemical and thermal stress may be similar in some respects, a number of the synthetic responses are clearly different.

Animals↗
PubMed1977

Axoplasmic flow in myelinated and unmyelinated nerves.

[14C]Leucine was injected into the floor of the IVth ventricle of rabbits in order to label the axoplasmic flow of proteins in the efferent fibres of the vagus nerve. At intervals from 6 h to 180 days after injection, the rabbits were sacrificed and the cervical and abdominal vagus and recurrent laryngeal nerves removed. The radioactivity in the protein, lipid and low molecular weight fractions of the nerve segments was estimated by liquid scintillation counting. Two rates of axoplasmic flow were thus demonstrated in the abdominal vagus nerve; a fast rate of about 450 mm/day and a slow rate of 30 mm/day. This agrees very well with previous work. Peaks of activity in the recurrent laryngeal nerve corresponded to rates of 9 and 270 mm/day, but their level was low, being not significantly above sciatic nerve background levels. The number of efferent fibres in the two nerves and the corresponding axonal areas were calculated in order to estimate the amount of labelled material in the flow. The abdominal vagus was shown to contain 4-5 times as much label per unit area of axoplasm as the recurrent laryngeal. A difference was therefore demonstrated in the same anatomical nerve between myelinated fibres in the recurrent laryngeal and unmyelinated fibres in the abdominal vagus nerve, both in the rates of flow and in the amounts of material contained in the flow.

Animals↗