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Biomedical subjects

E Kowalski

Publications and source records attributed to E Kowalski.

At least 19 recordsLinked to original sources
PubMed1995

Pressure effects on the stability of lipoxygenase: Fourier transform-infrared spectroscopy (FT-IR) and enzyme activity studies.

Fourier transform infrared spectroscopy (FT-IR) studies of lipoxygenase at pressures of up to 1.2 GPa have shown changes in the amide I' band which correlate to structural changes of the enzyme. The shift of the frequency maximum of the amide I' band at about 600 MPa suggests a cooperative change in the secondary structure of the protein. Studies of the changes in band width have shown the structural changes at 600 MPa to be irreversible. This has been confirmed by studies of enzyme activity after pressure treatment: exposure to 600 MPa for 30 min (40 degrees C) clearly reduced the activity of lipoxygenase. Anodic gel electrophoresis under non-denaturating conditions revealed a decrease in native protein parallel to the activity loss. A pressure-temperature-phase diagram for soybean lipoxygenase was established.

Enzyme Stability↗
PubMed1987

Persistent rotavirus infection in mice with severe combined immunodeficiency.

Rotaviruses are important pathogens of human infants and the infants of many animal species. The disease produced by these viruses can be described as an acute, self-limiting diarrheal disease, with virus replication localized to the differentiated epithelial enterocytes of the small intestine. Immunologically normal infants shed virus for approximately 5 to 12 days after the onset of infection. Recently, it has been shown that rotavirus can produce a chronic infection in severely immunocompromised children, with virus shedding and intermittent diarrhea lasting from 6 weeks to 2 years (G. A. Losonsky, J. P. Johnson, J. A. Winkelstein, and R. H. Yolken, J. Clin. Invest. 76:2362-2367, 1985; F. T. Saulsbury, J. A. Winkelstein, and R. H. Yolken, J. Pediatr. 97:61-65, 1980). These findings point to an important role for the immune system in recovery from the disease. The study described here examined the outcome of murine rotavirus infection in mice with severe combined B- and T-cell immunodeficiency (SCID) and in immunologically normal seronegative BALB/c mice. Persistent rotavirus infection was established in all mice with SCID which had been inoculated orally as pups. Low levels of virus replication and constant fecal virus shedding characterized the chronic infection. This is the first report of a persistent rotavirus infection in an animal model.

Animals↗
PubMed1985

Effect of age and malnutrition on rotavirus infection in mice.

Litters of malnourished and normally nourished suckling mice of various ages were fed mouse rotavirus (10(5) ID50). Infection was monitored by immunofluorescent staining of isolated epithelial enterocytes 24, 28, and 72 h after virus ingestion; enzyme linked immunosorbent assay of daily fecal samples; and determining the severity of diarrhea by noting the color and consistency of the feces and the presence or absence of staining. In malnourished mice 5 to 9 days old, all the parameters of infection were significantly greater than in their normally nourished counterparts. However, in mice 10 to 14 days old the differences in extent and severity of infection in malnourished and normally nourished animals was not significant. After 15 days of age there were low levels of virus shedding and antigen-positive enterocytes in both malnourished and normally nourished animals, but there was no diarrhea in either group. Therefore it appears that nutritional manipulation, resulting in malnutrition, does not alter the state of refractoriness to symptomatic rotavirus infection in mice greater than 15 days old.

Age Factors↗