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Biomedical subjects

E A Cameron

Publications and source records attributed to E A Cameron.

12 recordsLinked to original sources
PubMed2000

Heterorhabditis bacteriophora: seasonal dynamics and distribution in a stand of sugar maple, Acer saccharum.

The seasonal dynamics of an indigenous entomopathogenic nematode, a new strain of Heterorhabditis bacteriophora, "Nittany strain," in a stand of sugar maple, Acer saccharum, were examined utilizing a Galleria mellonella bait method. Seasonal dynamics are described in relation to soil temperature; occurrence is related to distance from a tree bole. A correlation between soil temperature and the number of infected G. mellonella was observed. Soil temperature had a significant effect on the number of positive samples, i.e., soil samples containing infected G. mellonella, obtained. In addition, seasonality had a significant effect on whether positive samples were obtained on a given date. There was no significant difference in the abundance of positive samples among three distances from a tree bole, namely, at the base of the tree, 2 m from the bole, or at the dripline.

Animals↗
PubMed2000

Rupture of the pectoralis major: a meta-analysis of 112 cases.

Of about 150 cases reported in the literature on pectoralis major ruptures, 108 were selected as presenting enough data to be analyzed for cause, rupture site, injury mechanism, and treatment outcome. We added data on four of our own cases reported here. All patients yet reported have been men. Rupture of the PM occurs most commonly in sports during weight training, weight lifting, or wrestling when the arm is externally rotated and abducted. Most reported ruptures are complete and are located at the insertion to the humerus. Work-related injuries occur more often at the musculo-tendinous junction. The prognosis is related neither to the age of the patient nor to the location of the rupture. Surgical treatment, preferably within the first 8 weeks after the injury, has a significantly better outcome than conservative treatment or delayed repair.

Adolescent↗
PubMed1998

Coeliac disease presenting with intraperitoneal haemorrhage.

A 42-year-old man, who was previously fit and well, presented in haemorrhagic shock due to a spontaneous left mesocolonic haematoma and intraperitoneal bleed. His INR was noted to be raised on admission. Later investigations showed him to have villous atrophy on biopsy of the second part of his duodenum and a positive anti-reticulin antibody. His duodenal biopsy and INR normalized on a gluten-free diet. Coeliac disease may present with a single vitamin deficiency with potentially catastrophic results.

Adult↗
PubMed1989

Magnesium metabolism in essential hypertension.

Hypertension is a complex, heterogeneous disorder of which the exact etiology is unknown. The difficulty in ascribing an independent role to a single dietary constituent in blood pressure regulation may be due to interactions among nutrients which influence blood pressure. The effect of any one nutrient, particularly magnesium, on hypertension should be considered within the context of overall nutrition in each patient. Clinical, experimental and epidemiologic studies support the role of magnesium in hypertension, whereas a few studies negate this role. Magnesium ions are important in arterial smooth muscle contraction. Since magnesium is found mainly at the inner surface of the cell membranes, it could play a role in cell membrane permeability for sodium and calcium which is important in the etiopathogenesis of hypertension. Magnesium deficiency can predispose to increased contractility of the arteries and its excess can modulate smooth muscle contractility caused by bradykinin, angiotensin II, serotonin, prostaglandins and catecholamines. Magnesium therapy can prevent the development of resistant hypertension and arrhythmias in hypertensives with diuretic-induced hypomagnesemia. It might also reduce blood pressure at least up to 10/5 mm Hg provided adequate magnesium salts are given for an adequate period of time. In view of the still ill defined role of magnesium in hypertension, magnesium supplementation is advised only to those hypertensives who are receiving diuretics and develop resistant hypertension or who have frank magnesium deficiency. A diet rich in magnesium may be used for prevention of hypertension in predisposed communities because of the other advantages of such a diet in prevention.

Animals↗
PubMed1987

Does sodium play an adverse role in hypertension?

It is clear that salt is known to be a health hazard from the ancient times. Sodium intake, which was minimal during evolution, increased significantly with the civilization. The rise in prevalence of hypertension in populations with increased consumption of salt suggested a casual relationship. However, several of these studies showed conflicting results. Many investigators agree that salt-sensitive persons often have a family history of hypertension. Such individuals possess a sodium transport inhibitor in the arterial smooth muscle cells, which affects their sodium handling (as compared to other persons). However, many of the putative defects related to sodium can be dissociated from blood pressure and sodium consumption status. It is possible that calcium defects of deficiency of potassium and magnesium follow hypertension and sodium status. For example, the pressure response to sodium chloride may be dissociated from sodium, which may be secondary to adverse effects of chloride on calcium homeostasis. Clinical studies also indicate that the role of sodium is controversial in hypertension. Sodium restriction can benefit salt-sensitive persons and might not otherwise. However, most authorities believe that moderation of salt intake to a relevant extent is justifiable. Large scale, long-term intervention studies and shortterm clinical studies in different communities, in the light of recently investigated dietary factors, are necessary to establish the role of sodium in essential hypertension.

Animals↗
PubMed1981

Magnesium in atherosclerotic cardiovascular disease and sudden death.

Magnesium ions are important for maintaining the functional and structural integrity of the myocardium. Epidemiologic studies suggest that myocardial hypomagnecytia can predispose to sudden cardiac death and that hard water protective factor preventing heart attack could be magnesium. Recent studies show that infarcted portion of the myocardium has lowered magnesium content as compared to noninfarcted segment. Magnesium deficiency sensitises the myocardium to the toxic effect of various drugs, hypoxia etc. and magnesium administration is protective. The metabolic, biochemical and electrophysiologic effects of magnesium appear to be significant in treatment of myocardial ischaemia. Magnesium is a metal-coenzyme and activates adenosine-triphosphatase which may be inhibited by nonglucose fuels like lactate and free fatty acids. Magnesium deficiency may be responsible for the chronic electrical instability of the myocardium predisposing to sudden cardiac death. The acute precipitating stress dependent trigger which lie in the brain may also be related to magnesium. In addition to fast Na and Ca channels there could be a Mg-carrying transport system maintaining the electrical activity of the myocardium. There is sufficient evidence to suggest the use of magnesium salts against ischaemic heart disease and sudden cardiac death. Magnesium is cardioprotective and influences action potential duration, membrane potential and perhaps maintains the fast response. The therapeutic and prophylactic value of magnesium needs further assessment.

Adult↗