Biomedical subjects
Publications and source records attributed to A M Gordon.
Strychnine intoxication is manifested by agitation, muscle spasms, and convulsions. We report a case in which intractable convulsions led to severe lactic acidosis which secondarily resulted in visceral (lung, heart, kidney, liver, and brain) collapse and death. Aggressive therapy instituted in the emergency department and aimed at control of seizure activity and lactic acidosis may be lifesaving.
Twenty-five patients received 10 ml co-trimoxazole (800 mg sulphamethoxazole and 160 mg trimethoprim) and 25 a placebo by intravenous infusion during one hour from the commencement of surgery for vaginal hysterectomy with anterior colporrhaphy and posterior colpo-perineorrhaphy. Single-dose chemoprophylaxis with co-trimoxazole was shown to be effective in reducing the incidence of postoperative febrile morbidity and urinary tract infection, especially that caused by Proteus species.
Drug offences in addicts are often thought to indicate little more than continued dependency. In a four-year follow-up study of 60 men attending a drug clinic a history of repeated convictions for drug offences was found to be strongly related to patterns of delinquency. The following variables were associated with a history of repeated drug offences: a higher conviction rate for "non-drug" offences; younger age at first conviction; conviction preceding drug use; convictions for offences of sex and violence; longer prison sentences; and regular narcotic use and continued dependency at follow-up. Receiving a clinic prescription was not associated with a lower incidence of drug offences. Repeated drug offences identified a subgroup of drug users who were characterised by extensive sociopathic behaviour. Such offences should not be dismissed as an unavoidable, unimportant part of addiction.
Although carcinoma of the testicle is a rare lesion, one family physician saw three cases in 18 months. He diagnosed all correctly and referred the patients for treatment immediately. All three patients are living and well. We believe his alertness is worthy of note because, given the rarity of the lesion, a low index of suspicion and delayed diagnosis often occur, with less than desirable results.
Muscle contraction is initiated by an elevation in intracellular calcium. The transient change in free calcium to a brief depolarization, the calcium transient, can be recorded using a calcium luminescent protein, aequorin. The calcium transient precedes force, peaking while force is rising and returning to the resting level as peak force is achieved. In single barnacle muscle fibers microinjected with aequorin, shortening the muscle during the declining phase of the calcium transient produces an addition light signal, indicating extra free calcium in the sarcoplasm. The amount of additional light is larger with larger length changes. It is also larger if the shortening occurs early in the calcium transient rather than later. The amount of this extra calcium correlates well with the instantaneous level of the calcium transient and not with the instantaneous force level. It is argued in a speculative manner that this extra calcium is coming from the myofilaments. This supports the hypothesis that calcium binding to the myofilaments is rapid and reversible, that reaccumulation of calcium into the sarcoplasmic reticulum (SR) could occur long before relaxation begins and that relaxation of tension could occur by some process other than the mere removal of calcium from the myofilaments.
After rats had been fed a low-potassium diet for 4 to 8 weeks, skeletal muscle showed ultrastructural changes involving membranous organelles. Mitochondria were often swollen, condensed, or disintegrated. The transverse tubules were disoriented, focally dilated, and tortuous. The sarcoplasmic reticulum showed various degrees of dilatation. Vacuoles of different sizes occurred frequently. Whirls of membranes were closely associated with any of the membranous organelles, especially near an orifice of a transverse tubule. Supplementation of potassium reversed these changes. These findings are very similar to those in patients with hypokalemic periodic paralysis. The vacuolar myopathy in these patients may be secondary to the electrolyte alteration in skeletal muscles, and the chronic weakness of some patients may be due to excitation-contraction uncoupling as a result of the involvement of sarcotubular systems.
The author outlines the hypothesis of the role of amines in depression. Postulating that depression involves a derangement of amine metabolism in which a deficit of amine activity occurs in certain areas of the brain which in turn results in altered transmission, the theory proposes that certain antidepressant drugs effect an elevation of brain amines restoring normal transmission and relieving the depression.
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In single muscle fibers from the giant barnacle, a small decrease in muscle length decreases both the calcium activation and the peak isometric tension produced by a constant current stimulus. The effect is most pronounced if the length change immediately precedes the stimulation. In some cases, the decrease in tension with shortening can be accounted for almost entirely by a decrease in calcium release rather than changes in mechanical factors such as filament geometry. During the constant current stimulation the muscle membrane becomes more depolarized at longer muscle lengths than at the shorter muscle lengths. Under voltage clamp conditions, when the membrane potential is kept constant during stimulation, there is little length dependence of calcium release. Thus, the effect of length on calcium release is mediated through a change in membrane properties, rather than an effect on a subsequent step in excitation-contraction coupling. Stretch causes the unstimulated fiber membrane to depolarize by about l mV while release causes the fiber membrane to hyperpolarize by about the same amount. The process causing this change in potential has an equilibrium potential nearly 10 mV hyperpolarized from the resting level. This change in resting membrane potential with length may account for the length dependence of calcium release.
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Three- and four-year-old brothers, ostensibly with a nonprogressive spastic quadriparesis, had retinitis pigmentosa and mental retardation. One had clinical deafness. The brothers showed little developmental progress in infancy and exhibited deterioration in childhood. Known metabolic and acquired causes were excluded. Although they have some features of several other syndromes,the condition reported here is unique.
In single muscle fibers, small (1 percent) changes of length have a marked effect of both the calcium activation and the tension elicited by a constant current stimulus. The decrease in tension with shortening is accounted for almost entirely by a decrease in calcium release, rather than by changes in mechanical factors, such as filament geometry.
Zinc-free insulin elicited a reduction in the potassium conductance of muscle fibers from potassium-depleted muscle, which led to depolarization, blockage of action-poteintial mechanism, and paralysis. These changes are proposed as the mechanism of insulin-induced paralysis in patients with hypokalemic periodic paralysis. A similar effect by concanavalin a suggests that the effect may be mediated through the insulin receptors.
Treatment under conditions of gnotobiotic isolation can augment the stress of adaptation to a diagnosis of leukaemia. Identification of the psychological problems experienced in isolator treatment can contribute to the effective maintenance of therapy. Individual patterns of adjustment to treatment relate to the psychological mechanisms of defence employed to contend with the dependent position enforced by isolation. Psychiatric assessment can assist both patients and nursing staff with the management of their separate difficulties in this unfamiliar treatment situation. Psychological features of isolator treatment in ten patients with acute leukaemia are described and suggestions proposed for psychological management of patients under isolator conditions.
A case of septicaemia due to Neisseria catarrhalis occurring in an immunosuppressed individual is described. The clinical syndrome closely resembled that of N. meningitidis septicaemia. The potential pathogenicity in the immunosuppressed patient, of organisms usually considered harmless is stressed.
Treatment under conditions of gnotobiotic isolation can augment the stress of adaptation to a diagnosis of leukaemia. Identification of the psychological problems experienced in isolator treatment can contribute to the effective maintenance of therapy. Individual patterns of adjustment to treatment relate to the psychological defence mechanisms employed to contend with the dependent position enforced by isolation. Psychiatric assessment can assist both patients and nursing staff with the management of their separate difficulties in this unfamiliar treatment situation. Psychological features of isolator treatment in ten patients with acute leukemia are described and suggestions proposed for psychological management of patients under isolator conditions.
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