Improved spectrophotometric assay for beta-lactam residues in kidney tissue.

This paper describes a detection system for beta-lactams using a commercially prepared carboxypeptidase enzyme (CPase) and a substrate system in which lactic acid is cleaved from a synthetic peptide, N alpha-N epsilon-diacetyl-L-lysyl-d-alanyl-d-lactic acid. The lactate is itself oxidized by lactate dehydrogenase to form NADH. Oxidized NAD+ is regenerated by diaphorase with the simultaneous reduction of the colourless 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride hydrate (INT) indicator substrate to produce a red-mauve colour that is proportional to CPase activity.

Mechanism of bacitracin resistance in gram-negative bacteria that synthesize exopolysaccharides.

Four representative species from three genera of gram-negative bacteria that secrete exopolysaccharides acquired resistance to the antibiotic bacitracin by stopping synthesis of the exopolysaccharide. Xanthomonas campestris, Sphingomonas strains S-88 and NW11, and Escherichia coli K-12 secrete xanthan gum, sphingans S-88 and NW11, and colanic acid, respectively. The gumD gene in X.

Sphinganase, a new endoglycanase that cleaves specific members of the gellan family of polysaccharides.

A sporeforming gram-positive aerobic bacterium was isolated from soil and shown to secrete an endoglycanase that cleaves the tetrasaccharide backbone structure of specific members within the gellan family of related bacterial exopolysaccharides. We refer to these polysaccharides as sphingans. The structures of the sphingans differ by the type and position of side groups that are attached to the backbone.

Stage-specific effects of X-irradiation on yeast meiosis.

Previous work has shown that cdc13 causes meiotic arrest of Saccharomyces cerevisiae following DNA replication by a RAD9-dependent mechanism. In the present work, we have further investigated the implicit effects of chromosomal lesions on progression through meiosis by exposing yeast cells to X-irradiation at various times during sporulation. We find that exposure of RAD9 cells to X-irradiation early in meiosis prevents sporulation, arresting the cells at a stage prior to premeiotic DNA replication.

Isolation of new aureobasidium strains that produce high-molecular-weight pullulan with reduced pigmentation.

New isolates of Aureobasidium pullulans were obtained from plant leaf surfaces gathered in San Diego County. The new fungal isolates were identified as A. pullulans on the basis of the appearance of polymorphic colonies formed on agar plates, the electrophoretic profiles of repeated genomic DNA sequences, and the production of pullulan in shake flask cultures.

An analysis of rising health care costs.

Why are medical costs rising so rapidly? What are the factors involved that influence those costs? Does inflation affect health care costs? Can anything be done? The solutions to these complex issues are not clearly understood. It is clear, however, that the resolutions to these questions must be found quickly. If the causes of rising medical care costs are not promptly diagnosed and treated, we may find our economic health to be in critical condition.

Hospital marketing: a new frontier.

Competition is now forcing hospitals to become more efficient and market-wise. This article investigates the past, present and future trends in hospital marketing. Dramatic changes are taking place at a staggering pace in the health care arena.

Accumulation of the insecticidal crystal protein of Bacillus thuringiensis subsp. kurstaki in post-exponential-phase Bacillus subtilis.

A gene from Bacillus thuringiensis subsp. kurstaki that codes for a Lepidoptera-specific insecticidal toxin (delta-endotoxin) was engineered for expression in Bacillus subtilis. A low-copy-number plasmid vector that replicates in Escherichia coli and B.

Structural relatedness between mosquitocidal endotoxins of Bacillus thuringiensis subsp. israelensis.

A mosquitocidal toxin gene, cloned from Bacillus thuringiensis subsp. israelensis, was introduced into mutant crystal-negative B. thuringiensis subsp.

Clustering of mutations blocking synthesis of xanthan gum by Xanthomonas campestris.

Mutations that block the synthesis of xanthan gum by Xanthomonas campestris B1459S-4L-II were isolated as nonmucoid colonies after treatment with ethyl methanesulfonate. Complete libraries of DNA fragments from wild-type X. campestris were cloned into Escherichia coli by using a broad-host-range cosmid vector and then transferred into each mutant strain by conjugal mating.

Structural similarity between the lepidoptera- and diptera-specific insecticidal endotoxin genes of Bacillus thuringiensis subsp. "kurstaki" and "israelensis".

A gene from Bacillus thuringiensis subsp. "israelensis" was cloned from the large plasmids of this subspecies and was shown to code for a mosquitocidal polypeptide. The gene could be expressed in either Escherichia coli, Bacillus subtilis, or B.

Effect of ticlopidine and prostaglandin E on endotoxin-induced pulmonary platelet sequestration in vivo.

Prostaglandin E1 has earlier been shown to decrease pulmonary platelet trapping (PPT) following shock. This experiment was performed to evaluate a new method to study PPT in vivo, and to study the effect of prostaglandin E1 and a new antiplatelet drug (ticlopidine) on PPT in rabbits after i.v.

Effects of acetylsalicylic acid and prostaglandin on endotoxin-induced pulmonary platelet sequestration.

Previous experimental studies have shown that soft tissue trauma and endotoxin shock cause pulmonary platelet trapping. In the soft tissue trauma model it has been found that this event can be obviated by pretreatment with aspirin and prostaglandin E1 in combination. This study was made to determine the effect of these two drugs on endotoxin-induced pulmonary platelet trapping.

Digital modulator and synchronous demodulator system: an alternative to the analog phase detector.

A digital modulator and synchronous demodulator system has been developed which more effectively recovers signals buried in noise than does its analog counterpart. Circuitry of integrated design is described for controlling the modulation in physical measurements and the simultaneous, synchronous demodulation and conversion of the signal into a binary number. This system is especially useful when interfaced with a laboratory computer.

Mafenide acetate solution dressings: an adjunct in burn wound care.

A continuation of the study of 5% aqueous Sulfamylon solution dressings in burned patients was analyzed in 150 consecutive cases. The rate of invasive infection and mortality was not excessive. Dressings were used as an adjunct to other topical chemotherapeutic agents as well as homo/heterograft skin in the overall burn care program.