Preweanling rats: recovery from lateral hypothalamic damage

Preweanling male and female albino rats sustained lateral hypothalamic area (LHA) destruction at 10 days of age. Pups with bilateral LHA destruction (Bi-LHA) displayed the lateral hypothalamic recovery syndrome (LHRS) and recovered voluntary feeding and drinking between 44-75 days of age. The Bi-LHA rats of both sexes showed permanent deficits (through 200-275 days of age) in responding to hydrational challenges and did not feed in response to 2-deoxy-D-glucose treatment. Male Bi-LHA rats' body weights were permanently depressed by 20%-25%, whereas female body weight depression was only temporary. Rats sustaining LHA destruction on one side of the brain (Uni-LHA) displayed an abbreviated LHRS, recovering voluntary feeding and drinking by 25-32 days of age. The Uni-LHA rats showed some permanent deficits in responding to hydrational challenges, yet they displayed the same sex differential for body weight regulation as the Bi-LHA rats. The results of this investigation demonstrate nearly identical effects of LHA destruction whether sustained preweaning, postweaning, or during adulthood.     

Guanidines as analogs of histamine and antihistamines on the isolated guinea-pig ileum

The present work describes the interaction of phenylguanidine and cyclohexylguanidine with receptor structures of the isolated guinea-pig ileum. It is suggested that phenylguanidine in the range of 0.2-2 mM, acts in a way similar to histamine. At lower concentrations in the bath, phenylguanidine and cyclohexylguanidine, behave as competitive antagonists of histamine, with Ki values close to 0.1 mM and 0.4 mM, respectively. At higher concentrations phenylguanidine acts as agonist with a Kn near 0.3 mM; the Kn for histamine was found to be 0.127 muM, in agreement with previous data from the literature. The agonistic action of phenylguanidine is inhibited by promethazine and atropine, which have Ki values of 0.342 muM and 0.575 muM, respectively. Cyclohexylguanidine is devoid of spasmogenic activity, and this was attributed to the lack of aromatic character and to the bulkiness of the cyclohexyl side chain.     

Contractile function of heart muscle from burned guinea pigs

Atrial muscle isolated from burned guinea pigs was used to assess myocardial contractile changes associated with thermal injury. Muscle was obtained 16-18 hours after the animals were subjected to sham burn (controls) or to scald burn equivalent to 16% of total body surface area. Isometric contractile tension (CT) and its maximal rate of increase (+dT/dt) were not significantly altered by burn. However, the maximal rate of relaxation (-dT/dt) was uniformly less in muscle from the burned group, and this difference was significant at several time intervals after in vitro contractile responses were elicited. Similarly, -dT/dt responses to increased stimulation frequency (0.1-3.0 Hz) and to increased calcium ion concentration (1.0-10.0 mM) were generally less in the burned group, whereas corresponding CT and +dT/dt responses of the burn and controls groups were not significantly different. Present data indicate that atrial muscle removed from moderately burned guinea pigs exhibits normal contractile capabilities, but may be characterized by impaired relaxation properties.     

Myocardial infarct extension: incidence and relationship to survival

Myocardial infarct extension, defined as reelevation or reappearance of creatine phosphokinase-MB (CK-MB) 48 hours after the onset of symptoms, was evaluated prospectively in 56 consecutive patients with acute myocardial infarction. Myocardial infarct extension occurred in eight patients (14%). The sensitivity, specificity and predictive accuracy in the diagnosis of myocardial infarct extension were 63%, 85% and 42%, respectively, for recurrent chest pain requiring morphine; 50%, 65% and 19% for recurrent ST-segment elevation on routine 12-lead ECGs; and 88%, 63% and 28% for reelevation of total CK. Three of the eight episodes of extension were clinically silent. Four of eight patients (50%) with extension died, compared with one of 46 patients (2%) without extension (p = 0.0009). CK-MB persisted for 72 hours or longer in 16 patients and identified seven of eight patients who subsequently had infarct extension. We conclude that myocardial infarct extension is an infrequent complication of acute myocardial infarction and is associated with a very high mortality rate. Persistence of CK-MB for 72 hours or more identifies a subgroup of patients at high risk for subsequent infarct extension and death.     

Lung cancer--management and outcome in Glasgow, 1991-92

Current practice and outcome for patients with lung cancer were determined by retrospective case note review of a random sample of all lung cancer cases registered for a calendar year and augmented by review of all surgical and radical radiotherapy cases. A total of 262 patients - 231 patients less than 75 years of age and 31 patients more than 75 years of age - represented 83% of the random sample. Eighty-three per cent of patients were seen within 2 weeks of referral. One-third reported symptoms occurring for less than 1 month and one-third had experienced symptoms for more than 3 months. The median time interval from first hospital contact until the making of a management decision was 18 days. The median interval from first contact to surgery was 63 days, and to starting radical radiotherapy 70 days. Histological confirmation was obtained in 69% of patients. Ten per cent of all lung cancer patients were calculated to have received chemotherapy. Five per cent of the whole cohort had definitive surgery and 64% of these were judged to be free of the disease at 3 years. Overall survival was 9% at 3 years, with no differences relating to cell type or area of residence. Many areas of good practice have been identified, but the lack of tumour staging or performance status data, the low proportion receiving chemotherapy or definitive surgery and the poor outcome after radical radiotherapy indicate the need for prospective audit and feedback of results. The long time interval from management decision to surgery and radiotherapy suggests organizational issues which need attention.