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Biomedical subjects

A Morris

Publications and source records attributed to A Morris.

At least 271 records · Page 15Linked to original sources
PubMed1975

Progressive pulmonary insufficiency and other pulmonary complications of thermal injury.

Progressive pulmonary insufficiency appears to be a universal response to the lung to a variety of injuries which damage the pulmonary-capillary emdothelium. Persistent hyperventilation, unresponsive to the administration of oxygen, is the earliest clinical sign of this complication of trauma and should prompt close monitoring of pulmonary function (measurement of arterial blood gas and pH levels, Vd/Vt A-aDo2, minute ventilation, vital capacity and inspiratory force) to assess the severity of the disease, the need for mechanical ventilatory support and the effectiveness of treatment. Other pulmonary complications of burn injury range from carbon monoxide poisoning and narcotics overdosage in the immediate postburn period through marked hyperventilation directly related to burn size occurring in the absence of significant parenchymal change to later occurring hematogenous and airborne pneumonia. Inhalation injury, a chemical tracheobronchitis which significantly increases the mortality of a given-sized burn, may be present immediately postburn but clinically inapparent for 48-72 hours. 133Xenon lung scans permit early diagnosis of this pulmonary injury and the timely institution of a graduated therapeutic response keyed to the severity of pulmonary disability. Knowledge of the pathogenesis of each of these complications is requisite for the physician caring for burn patients and permits the employment of rational preventive and therapeutic measures.

Burns↗
PubMed1972

Novel method for detection of beta-lactamases by using a chromogenic cephalosporin substrate.

A new cephalosporin with a highly reactive beta-lactam ring was found to give an immediate color change in the presence of beta-lactamases from many bacteria, including staphylococci, Bacillus species, Enterobacteriaceae, and Pseudomonas. The reaction is confined to organisms producing beta-lactamases, but it is sufficiently sensitive to indicate the presence of this enzyme is small amounts in strains previously considered not to produce it. The compound has an unusual ultraviolet spectrum, and the color change can be followed quantitatively by measuring changes in absorption which occur in the 380- to 500-nm region, where cephalosporins normally have no absorption. The development of color is thought to be a consequence of the beta-lactam ring being unusually highly conjugated with the 3-substituent. Although in the bacteria only beta-lactamases produce this color change, it was found that serum and tissues from experimental animals also rapidly produced the colored breakdown product, which was then excreted in the urine. The mechanism of the mammalian breakdown was considered to be different from that found in bacteria.

Bacillus cereus↗
PubMed1972

Inhibition of beta-lactamases by beta-lactam antibiotics.

The inhibitory properties of a selected number of beta-lactam antibiotics were studied, with the use of three distinct types of beta-lactamases. The three enzymes were found to be distinguishable on the basis of their susceptibility to inhibition. Not one of the potential inhibitors tested was found to be a potent inhibitor of all three enzymes, but nafcillin possessed the broadest inhibitory activity. The enzyme isolated from Enterobacter cloacae was found to be the most susceptible. In some cases, the degree of inhibition varied with the time of incubation, and, depending upon the time chosen, widely different observations could be made. It is suggested that, in studies such as these, every consideration should be given to the period of incubation and to the concentration of inhibitor employed. Mixtures of inhibitor and cephaloridine did not always act synergistically against growing bacteria, and a number of reasons for failure are suggested.

Anti-Bacterial Agents↗
PubMed1972

Correlation between hydrolysis of the -lactam bond of the cephalosporin nucleus and expulsion of the 3-substituent.

The hydrolysis of two cephalosporins by three different beta-lactamases has been studied. Each enzyme caused a decrease in ultraviolet absorption, a loss of biological activity, and the release of the leaving group from the 3-position. The changes occurred at the same rate and to the same extent with each enzyme, and it is inferred that the loss of the leaving group is a consequence of, and not a prerequisite for, hydrolysis of the beta-lactam ring.

Absorption↗
PubMed1972

Disordered blood coagulation in burned children receiving high molecular weight dextran.

Coagulation studies were performed on nine children with burns. Four of these children received treatment which included intravenous dextran; all four showed abnormalities of coagulation and two of them developed a bleeding state. No abnormalities of haemostasis were detected in the remaining five children who had comparable degrees of burns but whose treatment did not include intravenous dextran.

Blood Coagulation↗