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Biomedical subjects

J I Smith

Publications and source records attributed to J I Smith.

7 recordsLinked to original sources
PubMed1992

Structure, kinetics, and function of human and rhesus plasma prekallikreins are similar.

To determine if rhesus monkeys (Macaca mulatta) could serve as a model for studying the role of the contact system in the pathophysiology of human infections, we compared structural, kinetic, and functional characteristics of plasma prekallikrein and its activation products in rhesus and humans. Three prekallikrein variants (85-, 89- and 93-kDa) were revealed in rhesus plasma as compared with the two variants (85- and 88-kDa) in human plasma by immunoblotting with the monoclonal antibody MAb 13G11. The prekallikrein concentration in rhesus plasma was 1.5-fold that in human plasma as determined by computerized immunoblot analyses (CIBA) and amidolytic activity. The electrophoretic mobility of prekallikrein from plasma of both species increased after deglycosylation. Inhibition of prekallikrein activation by MAb 13G11 was 55% (rhesus plasma) and 76% (human plasma), with similar inhibition curves. Immunoblots of activated rhesus plasma showed prekallikrein, complexes of kallikrein with C1 inhibitor, alpha 2-macroglobulin and approximately 60-kDa inhibitor(s) (viz. antithrombin III), and 45-kDa fragments, like those in activated human plasma. Concentrations and molecular masses of factor XII and high molecular weight kininogen were similar in rhesus and human plasma. The activated partial thromboplastin time (APTT) and prothrombin time were 20.1 +/- 1.6 and 9.7 +/- 0.3 s for rhesus and 32.0 +/- 5.6 and 12 +/- 0.5 s for human plasma. Human and rhesus APTTs were similar when prekallikrein concentrations in human and rhesus plasma became alike by adding human purified prekallikrein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Prospective, double-blind, concurrent, placebo-controlled clinical trial of intravenous ribavirin therapy of hemorrhagic fever with renal syndrome.

A prospective, randomized, double-blind, concurrent, placebo-controlled clinical trial of intravenous ribavirin (loading dose of 33 mg/kg, 16 mg/kg every 6 h for 4 days, and 8 mg/kg every 8 h for 3 days) was conducted in 242 patients with serologically confirmed hemorrhagic fever with renal syndrome (HFRS) in the People's Republic of China. Mortality was significantly reduced (sevenfold decrease in risk) among ribavirin-treated patients, when comparisons were adjusted for baseline risk estimators of mortality (P = .01; two-tailed). HFRS typically consists of five consecutive but frequently overlapping clinical phases. Only occurrence of oliguric phase and hemorrhage was associated with severity of clinical disease in the placebo group. Ribavirin therapy also resulted in a significant reduction in the risk of entering the oliguric phase and experiencing hemorrhage. The only ribavirin-related side effect was a well-recognized, fully reversible anemia after completion of therapy.

Anemia, Hemolytic↗
PubMed1991

Interruption study of viremia of patients with hemorrhagic fever with renal syndrome in the febrile phase.

Kinetic changes of viremia were observed in 287 cases of hemorrhagic fever with renal syndrome (HFRS) in whom ribavirin was administered with double blind random control studied by means of virus isolation, indirect immunofluorescence assay and enzyme-linked immunosorbent assay. The positive rate of viremia was 79.7% (Sp = 3%) and positive rate of HERS IgM was 85% (Sp = 3.1%) before treatment. Viremia could be interrupted by ribavirin as in the ribavirin treated group, the viremia positive rate decreased, duration of viremia was shortened, viral antigen products, virus titer and HFRS IgG antibody level were reduced as compared with the control group. This showed that viremia was very frequent in patients in the febrile phase and ribavirin is an effective antiviral drug in HFRS during the febrile phase. Dosage and course of treatment of this drug are discussed.

Double-Blind Method↗
PubMed1990

In vitro surface properties of the newly recognized gastric pathogen Helicobacter pylori.

There appears to be a particular association between Helicobacter pylori and the gastric antrum, but the mechanisms by which the organism adheres to and colonizes the gastric mucosa are unclear. Surface hydrophobicity and surface charge mediate the adherence of other bacterial pathogens to mucosal epithelial cell surfaces. Therefore, in this study we characterized both the surface hydrophobicity and the surface charge of 10 H. pylori strains grown in broth culture. Four complementary methods were used to determine hydrophobicity: hydrophobic interaction chromatography, the salt aggregation test, comparison of bacterial adherence to polystyrene with adherence to sulfonated polystyrene, and measurement of contact angle with droplets of water. Three of the methods (salt aggregation test, adherence to polystyrene, and contact angles) indicated that each of the 10 strains expressed a relatively hydrophilic cell surface. In contrast, hydrophobic interaction chromatography determinations with both phenyl- and octyl-Sepharose suggested that the H. pylori strains were relatively hydrophobic. However, tetramethyl urea (0.4 M) did not reduce the binding of H. pylori to phenyl-Sepharose columns. DEAE-cellulose ion-exchange chromatography showed that each of the 10 strains of H. pylori had a surface which, overall, was highly negatively charged. We conclude that H. pylori expresses an overall relatively hydrophilic and negatively charged surface in vitro.

Bacterial Adhesion↗
PubMed1989

Rapid diagnosis of malaria by acridine orange staining of centrifuged parasites.

A rapid diagnostic test for malaria based on acridine orange staining of centrifuged parasites in a microhaematocrit tube ('QBC' tube) was compared with the thick blood smear in 12 volunteers experimentally infected with Plasmodium falciparum, 408 residents of a malaria endemic area, and 180 hospital patients with suspected malaria. In the experimentally infected volunteers, the QBC tube test and the thick blood smear were comparable and the QBC tube could detect as few as 4 parasites/microliter blood. When used for mass screening in the field study, the test had a sensitivity of 70% for the diagnosis of malaria compared with 92% for a single thick blood smear. However, when used to diagnose malaria in hospital patients, the test detected as few as 3 parasites/microliter in 91 of 92 patients with asexual parasitaemia. For the three studies, the QBC tube was highly specific (98.4%), indicating malaria in only 8 of 487 subjects with negative blood films. The species of parasite was correctly identified in 77% of species. Processing the QBC tube was easier and much more rapid than was processing a thick blood smear, taking only 5 min for centrifugation and 5 min for examination. The QBC tube is not a substitute for the blood smear, but its speed and ease of use make it an important new tool for the diagnosis of malaria.

Acridine Orange↗
PubMed1976

Circuit librarian serves five hospitals in shared program.

There is increasing emphasis on continuing education of hospital personnel, who need and want access to information in order to be aware of advances in health care. Small hospitals cannot afford to duplicate extensive collections. Personnel of hospitals that are remote from urban centers often do not have opportunities to visit a resource library on a regular basis and do not have experience in searching the medical literature through the use of reference tools. It is increasingly evident that the circuit librarian program has served as a catalyst in establishing relationships between the hospitals and the university health sciences center. The director of the CHSL has consulted with the deans of the nursing and the medical schools and with various professors. They have promised that the schools will try to address identifiable continuing education needs or requests from the hospitals. Moreover, the circuit librarian meets with individual hospital personnel and then obtains information for them from the CHSL and its staff. The circuit librarian program is one way to meet community hospitals' needs for access to health sciences literature and to initiate peer interaction for information exchange.

Education, Continuing↗