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Biomedical subjects

J P Wright

Publications and source records attributed to J P Wright.

4 recordsLinked to original sources

Gentamicin and penicillin in the treatment of severe respiratory infections.

A combination of penicillin and gentamicin has been used for severely ill patients in a respiratory intensive care ward. It has been shown that predictable mean blood levels of gentamicin can be obtained in these patients by relating the dose to surface area (60 mg/m2/8 h). When renal function was initially normal it did not deteriorate during the course of therapy (10 days); gentamicin assays are not essential for safe treatment. In patients with renal failure, increasing the interval between doses also resulted in satisfactory levels, but close monitoring of the serum creatinine level is considered necessary. No clinical difference could be detected when gentamicin was given by constant or intermittent infusion.

Adult

Scanning electron microscopy of infective endocarditis.

As part of a study of the development of infective endocarditis in ncarcotic addicts, we sought to establish the feasibility of using scanning electron microscopy (SEM) to view the surface characteristics of human heart valves obtained at autopsy. Normal and infected heart valves from humans and animals were obtained at autopsy, fixed in formalin, and processed for SEM. Parallel samples from immediately adjacent regions were processed for light microscopy. Active and healed endocarditis were readily recognizable by SEM, and the observations correlated well with those made by light microscopy. The advantage of SEM in the study of endocarditis is that it provides significant information about damage to the endocardial surface across the entire valve. The relative proportions of fibrin, platelets, leukocytes, exposed stromal connective tissue and bacteria on the surface of a lesion can easily be analysed. SEM may prove particularly useful in the study of the pathogenesis of the early lesions of infective endocarditis on previously "undamaged" valves.

Animals

Jejunal secretion in response to a duodenal mixed nutrient perfusion.

A multilumen balloon tube constructed to separate duodenal and jejunal perfusion segments was placed in the proximal small bowel of 6 healthy volunteers. The effect of nutrient mixture in the duodenum on net jejunal water and electrolyte flux was then determined. The duodenum was perfused with a balanced electrolyte solution before and after the nutrient perfusion. Net water flux in the perfused jejunum changed from absorption 27.0 +/- 6.0 microliter/min/cm, (mean +/- SEM) to secretion 7.7 +/- 7.3 microliter/min/cm (P less than 0.025) during nutrient perfusion. There was also net chloride secretion and decreased net absorption of Na, K, and HCO3 (P less than 0.05). The jejunal absorption of water and electrolytes before and after the duodenal nutrient perfusion was the same. Results indicate that intestinal secretion may occur under physiologic conditions at sites remote to the application of food in humans.

Adult

Isolation of parietal cells from guinea-pig gastric mucosa and the immunological characterization of their antigenic structure.

A method is described for the isolation of parietal cells from the gastric mucosa of the guinea pig by enzymatic digestion with collagenase. A suspension was obtained that contained 70-80% parietal cells. About 80% of the cells were viable immediately after incubation, but viability dropped sharply after one hour. Parietal cells were identified by their morphology on light and electron microscopy, by their uptake of neutral red, by immunofluorescent staining and by carbonic anhydrase activity. Antibodies to four distinct parietal-cell antigens were obtained from rabbits immunized with the isolated parietal cells or fractions thereof. These antibodies were directed against the microsomal fraction of the parietal-cell cytoplasm, the plasma and nuclear membranes, the soluble proteins, and Castle's intrinsic factor. The antibody against the microsomal fraction, though reacting in the same way as the antibody to parietal cell canaliculi found in the serum of patients with pernicious anaemia, showed greater species specificity.

Anemia, Pernicious