The molecular mechanism of virus induction. I. A procedure for the biochemical assay of prophage induction

The basic conditions for use of a new biochemical assay of bacteriophage induction are described. This method is based on the read-through transcription of the tryptophan operon integrated into an "early" transcribed region of the bacteriophage phi80 or gamma genome. Inactivation of repressor molecules was assayed by measuring, in the presence of tryptophan, anthranilate synthetase activity in an Escherichia coli (trpE-) phi80 or gamma lysogen infected with phi80ptrp or gammaptrp, respectively, and treated with mitomycin C or UV irradiation. This method provides a sensitive and easy means to analyze the induction process.

Arterial blood gas tensions during upper gastrointestinal endoscopy

Arterial blood gas tensions were measured before and during upper gastrointestinal endoscopy, with (group I) and without (group 2) sedation with intravenous diazepam. There was a highly significant fall in the PaO2, which occurred in both groups and was therefore not attributable to diazepam. Measurement of FEV, and FVC before endoscopy had no predictive value for those patients whose PaO2 fell the most.

Adverse drug reactions-a matter of opinion

The accurate identification of adverse drug reactions (ADRs) is difficult because ADRs usually present no unique clinical or laboratory findings that demarcate them from the manifestations of concurrent illnesses. The identification of ADRs depends on the clinical assessments of physicians-sometimes the clinician treating the patient and at other times a clinical pharmacologist. Considering the complex and subjective nature of clinically identifying ADRs, how accurately are ADRs identified? To answer this question, three clinical pharmacologists each independently evaluated 60 selected cases to determine if medication, alcohol, or "recreational" drugs had caused the hospitalization. The three clinical pharmacologists agreed on only 30 cases (50%), and 27 of these were thought to be unrelated to medications. In 19 of the 30 cases about which the clinical pharmacologists disagreed, they disagreed on whether or not a medication-or alcohol-related event had occurred at all. The clinical pharmacologists disagreed with the physicians treating the patient in 22% to 37% of the cases, but because of the differences among the pharmacologists, the treating physicians agreed with at least one of them in 95% of the cases. Complete agreement between the clinical pharmacologists and the treating physicians occurred in 47% of the cases. This degree of disparity in the clinical identification of ADRs shows that the evaluation of ADRs is subjective and imprecise. The accurate identification of ADRs awaits the development of an objective technique for recognizing ADRs.

Amelioration of insulin lipoatrophy by dexamethasone injection

Widespread subcutaneous lipoatrophy occurred in a 47-year-old woman after subcutaneous injections of isophane insulin suspension for five months. Subsequent systemic treatment with a dexamethasone (0.08 mg/day) insulin mixture injected subcutaneously into the depressed areas resulted in an impressive return of subcutaneous tissue after eight months of continuous therapy.

Deoxyribonucleic acid polymerase II activity in an Escherichia coli mutator strain

The polB gene encoding deoxyribonucleic acid (DNA) polymerase II has been located close to a mutator gene, mutT1, in Escherichia coli. We find the DNA polymerase II prepared from mutT1, strains to be normal in reaction requirements, heat stability, and ability to remove mismatched bases at termini. Recombinants formed from a mutant defective in DNA polymerase II (polB100) and mutT1 are deficient in polymerase II and have the same mutator phenotype as mutT1. Our linkage analysis indicates that mutT1 and polB100 are not isoallelic.

Emotion-related gastritis

The relationship of emotional stress to abnormalities of the gastric mucosa was considered in a review of 788 consecutive upper gastrointestinal endoscopies. Fifty-three precent of patients with gastritis not related to any generally accepted predisposing or precipitating cause had significant emotional problems documented on their clinical records, while only 10% of the comparable group of duodenal ulcer patients and 25% of a similar group of medical in-patients had significant emotional problems documented. Since this difference was statistically significant (P less than 0.01 and P less than 0.05, respectively), the data suggest that emotional stress may play a contributing role in the production of gastric mucosal abnormaltieis.

Absence of effect of bran on blood-lipids

Healthy medical students were divided into two groups. One group was given double the normal fibre intake of their diet as a high-fibre-containing breakfast cereal; the other group (control) was given a breakfast cereal containing negligible amounts of dietary fibre. Otherwise the nutrient intake of the two groups was maintained constant. No differences in the serum-cholesterol, serum-triglyceride, serum-calcium levels were found between the two groups during or at the end of the study. The addition of a tolerable amount of dietary fibre to the diet does not affect serum-lipids.

Increase in urinary indican excretion in pancreatic steatorrhoea following replacement therapy

Urinary indican excretion was studied in 5 patients with steatorrhoea of pancreatic origin, 4 patients with steatorrhoea due to other causes, and 5 normal subjects. Treatment with pancreatic extract resulted in an immediate increase in indican excretion to above the normal range in patients with steatorrhoea due to pancreatic insufficiency. Administration of pancreatic extract did not result in a rise in the patients with steatorrhoea not due to pancreatic insufficiency, or in the normal subjects. In one patient with pancreatic insufficiency maintained on a low protein diet, the rise in indican excretion on replacement therapy was much slower and did not reach as high a level as in the patients on a normal protein diet. The possible mechanisms underlying these observations are discussed. It is suggested that the finding of a low indican excretion in the presence of steatorrhoea and its rise to above normal on pancreatic enzyme therapy is strongly suggestive of exocrine pancreatic insufficiency.

Control factors in the release of gastrin by direct electrical stimulation of the vagus

The release of gastrin by direct electrical stimulation of the vagus was studied together with the relative effects on the response of antral and duodenal acidification. As expected, gastrin levels increased to three times the normal simulated response following antral neutralization. In contrast, duodenal acidification failed to influence the vagal release of gastrin when the antrum was neutralized although it had a minor effect when the antrum was acidified. Thus the antral pH dominates over duodenal pH as a factor in controlling gastrin release. Surprisingly, atropine in doses which blocked acid release and produced marked cardiac effects failed to inhibit the release of gastrin from the antrum on vagal stimulation. This suggests that, using this model, vagal release of gastrin, if cholinergic, is highly resistant to atropine.

The content of vitamin E in British diets

1. Analysis of whole daily diets of normal subjects and of diets prepared in hospital to resemble the home diets of ambulant hospital patients showed that the majority of diets in Britain have a vitamin E content less than the lowest recommended intake of 5 mg/d, despite being generally satisfactory in calorie, protein and fat contents.

2. Comparison of measured intake of vitamin E with the intake calculated from food tables showed that the use of such tables may be unreliable.

3. Analyses of selected representative foods and of duplicate whole diets showed that the variations between measured vitamin E content of diets and those calculated from tables may be largely due to the great variability of tocopherol concentration in apparently similar samples of food.

Treatment of ocular myasthenia with corticotrophin

Nine patients with severe myasthenia gravis, including ocular symptoms, who did not respond to anticholinesterase therapy were given prolonged courses of corticotrophin. In all patients except one there was an initial deterioration, sometimes necessitating assisted respiration, followed by a marked improvement which persisted for many weeks and occasionally months. It is concluded that corticotrophin should be continued for at least two weeks as the onset of the remission might be delayed. Repeated courses or small maintenance doses prolonged the remission. Fluid retention and hypokalaemia were common unwanted effects but necessitated stopping the treatment in only one patient.