Parathyroid hormone (PTH) fragments relax the guinea-pig trachea in vitro

Synthetic bovine parathyroid hormone fragment containing the N-terminal 1-34 amino acids (bPTH-(1-34) ) relaxed the guinea-pig trachea constricted with histamine in vitro. Peptides with bovine and human sequences purchased from Peninsula Laboratories and Beckman Bioproducts produced similar effects. Substitution of methionine in positions 8 and 18 by norleucine did not affect this property of bPTH-(1-34). However, when the methionines were oxidized by treating the peptide with hydrogen peroxide, the peptide could no longer produce relaxation in the trachea. Oxidation of the methionine-replaced analog did not affect the action of the peptide on the trachea. It seems that the methionines per se are not necessary, but once oxidized the conformation of the molecule may be sufficiently altered to affect its ability to relax the trachea. While propranolol can block the relaxing action of isoproterenol, this blocking agent produces no inhibition of the bPTH-(1-34) effect. This action of PTH on the trachea may be related to cAMP because isobutyryl-methylxanthine, a phosphodiesterase inhibitor, potentiates and imidazole, a phosphodiesterase stimulator, inhibits the trachea relaxing action of bPTH-(1-34).     

Use of microcomputers for self-assessment and continuing education in anaesthesia.

The suitability of computer-assisted self-assessment was evaluated as a means of quality assurance in anaesthesia. Altogether 202 anaesthetists participated in four trials of the method. Analyses of their performance in a self-assessment programme dealing with obstetric anaesthesia showed significant differences in the levels of knowledge of anaesthetists practising for different numbers of years. The acceptability of computer-assisted self-assessment ranged from 91% to 100% for the four trials. Similar programs have been shown to be of value in medical education and thus computer-assisted self-assessment appears to fulfil simultaneously the functions of self-assessment and continuing education. The criteria for a method of quality assurance are met.     

Product reports from Japan

Product reports from Japan     

Hypertension and a digoxin-like substance in the plasma of dialysis patients: possible marker for a natriuretic hormone

Maintenance hemodialysis patients were randomly assigned to two groups based on the presence or absence of predialysis hypertension. Clinical profiles of the patients in the two groups were comparable except that there were more Blacks in the hypertensive group and that all the patients in this group received antihypertensive medications. Despite not taking any digitalis preparations, 10 of 12 hypertensives had measurable digoxin-like immunoreactive substance (DLIS) in their plasma. None of the 11 normotensives had detectable DLIS. Significantly higher (p less than 0.03) systemic vascular resistance was noted in hypertensives with DLIS compared to normotensives and hypertensives without DLIS. We propose that DLIS itself may be or may represent a marker for some vasopressive substance, possibly natriuretic hormone.     

A new metabolic labelling medium for Trichomonas vaginalis and Tritrichomonas foetus using 35S methionine

A metabolic labelling medium was devised for Trichomonas vaginalis and Tritrichomonas foetus utilizing 35S methionine. T. vaginalis cultured for 24h in the medium took up approximately 27% of the available label and increased greater than two fold in number. Counts per microgram of protein were 32,555 +/- 10% between different strains or identical strains in different labelling runs. T. foetus took up approximately 5% of the available label and increased greater than two fold in 24h. This resulted in specific labelling of 12,704 cpm/ug protein +/- 10% between different runs with the same strain.     

Inhibition of the growth of Ureaplasma urealyticum by a new urease inhibitor, flurofamide

Flurofamide (N-[diaminophosphinyl]-4-fluorobenzamide), a urease inhibitor, was a potent inhibitor of the growth of Ureaplasma urealyticum. As little as 10 microM flurofamide (2 micrograms/ml) prevented any growth, but U. urealyticum survived for about eight hours before colony counts become undetectable. Flurofamide was a specific inhibitor of U. urealyticum since it did not inhibit growth of four Mycoplasma species or Acholeplasma hippikon. Flurofamide was 1,000 times more active than acetohydroxamic acid and thus has promise as a chemotherapeutic agent and a biochemical tool.     

Predicting population coverage of T-cell epitope-based diagnostics and vaccines

Background  

T cells recognize a complex between a specific major histocompatibility complex (MHC) molecule and a particular pathogen-derived epitope. A given epitope will elicit a response only in individuals that express an MHC molecule capable of binding that particular epitope. MHC molecules are extremely polymorphic and over a thousand different human MHC (HLA) alleles are known. A disproportionate amount of MHC polymorphism occurs in positions constituting the peptide-binding region, and as a result, MHC molecules exhibit a widely varying binding specificity. In the design of peptide-based vaccines and diagnostics, the issue of population coverage in relation to MHC polymorphism is further complicated by the fact that different HLA types are expressed at dramatically different frequencies in different ethnicities. Thus, without careful consideration, a vaccine or diagnostic with ethnically biased population coverage could result.