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Biomedical subjects

F Morris

Publications and source records attributed to F Morris.

5 recordsLinked to original sources
PubMed1992

Impact of HIV infection on mycobacterial disease.

The current epidemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome has resulted in a worldwide resurgence of tuberculosis. In the United States, the number of new cases of tuberculosis has increased in the past five years, leading to a cumulative excess of about 15,000 cases. The clinical and epidemiologic picture of tuberculosis in AIDS patients differs drastically from the standard presentation of tuberculosis cases in HIV-negative patients. The diagnosis and management of tuberculosis, particularly atypical mycobacterial infections, present a challenge in HIV-infected patients. Prevention of the transmission of disease is a major concern. Since atypical mycobacterial infection and disease pose a greater management challenge, this article summarizes diagnosis and treatment of atypical mycobacterial infection in HIV-positive patients.

Adult↗
PubMed1979

An electron microscopic India ink technique for demonstrating capsules on microorganisms: studies with Streptococcus pneumoniae, Staphylococcus aureus, and Neisseria gonorrhoeae.

A technique using India ink in electron microscopic preparations was used to study bacterial capsules. Capsules were demonstrated on Streptococcus pneumoniae and Staphylococcus aureus (strain M and the Smith diffuse variant) from in vitro cultures. Two types of false capsules were observed on Neisseria gonorrhoeae grown in vitro or obtained from human urethral exudates. No true capsules were definitively identified on gonococci from these sources. The technique described does not require the use of specific anticapsular antibody or specific polysaccharide stains and permits the detection of artifacts that may, by the use of light microscopic methods, be misinterpreted as capsules.

Antigens, Bacterial↗
PubMed1979

Pili of Neisseria meningitidis: effect of media on maintenance of piliation, characteristics of Pili, and colonial morphology.

In contrast to information in the literature which indicates that meningococci rapidly lose pili upon cultivation in vitro, we found that piliation of meningococci could be maintained in vitro for 15 or more passages. Pili were present on all eight isolates tested, whether from asymptomatic carriers or from subjects with meningococcal disease. Complete loss of piliation occurred in the same two strains on two of the three media tested. On one medium (Thayer-Martin medium with supplement B), there was partial or complete loss of pili by all strains. The optimal medium for maintaining pili was chocolate agar with 1% IsoVitaleX; 95% or more of the microorganisms of six of the eight strains tested were piliated after 15 passages in vitro, and more than 60% of the microorganisms of the other two strains were piliated. Meningococci passed on this medium generally maintained their initial density of piliation (3 to 34 pili per diplococcus). The ability to predictably cultivate piliated meningococci in vitro and to select piliated and nonpiliated clones of the same strain should allow investigation of the biochemical and immunological properties of meningococcal pili as well as their possible role in the pathogenicity of Neisseria meningitidis.

Culture Media↗
PubMed1975

Hepatic lesions in mice after continuous inhalation exposure to 1,1,1-trichloroethane.

Male CF-1 mice (24 to 34 gm.) were exposed to either 250 p.p.m. or 1000 p.p.m. of 1,1,1-trichloroethane in air continuously for 14 weeks. Control mice were exposed to room air. Serial sacrifice of exposed and control mice from 1 to 14 weeks demonstrated significant changes in the centrilobular hepatocytes of animals in the 1000 p.p.m. group. Moderate liver triglyceride accumulation was evident in the 1000 p.p.m. group and peaked at 40 mg. per gm. of tissue (wet weight) after 7 weeks of exposure. Partial recovery was indicated by a decrease in the hepatic triglyceride level of 16 mg. per gm. by 14 weeks of exposure to 1000 p.p.m. Electron microscopic evaluation revealed that cytoplasmic altertions were most severe in centrilobular hepatocytes in the 1000 p.p.m. group and were mild to minimal in the 250 p.p.m. group. These alterations consisted of vesiculation of the rough endoplasmic reticulum, with loss of attached polyribosomes, increased smooth endoplasmic reticulum, microbodies, and triglyceride droplets. Some cells had ballooned cisternae of the rough endoplasmic reticulum. Necrosis of individual hepatocytes occurred in 40 per cent of the mice exposed to 1000 p.p.m. for 12 weeks. This necrosis was associated with an acute inflammatory infiltrate and hypertrophy of Kupffer cells. Comparison of these findings to the results obtained by other investigators studying dichloromethane indicates that the pathologic alterations observed with 1,1,1-trichloroethane were similar to those observed with dichloromethane, except for different time courses of the effects and different degrees of recovery. The toxic effects of 1,1,1-trichloroethane were of a type similar to those produced by carbon tetrachloride, but they appeared to be much less severe.

Animals↗