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.

Fetomaternal bleeding following diagnostic amniocentesis.

The frequency of diagnostic amniocentesis is increasing. Fetal bleeding and trauma have long been recognized to be complications of amniocentesis. For detection of fetomaternal bleeding, efficacy of modified Kleihauer-Betke staining and alpha-fetoprotein elevation in maternal blood was assessed. Preamniocentesis ultrasound scanning was found useful in reducing the incidence of fetomaternal bleeding and bloody taps. Elevation of alpha-fetoprotein was found to be a more sensitive indicator of fetomaternal bleeding than was modified Kleihauer-Betke staining. The use of alpha-fetoprotein to detect fetomaternal bleeding associated with amniocentesis is suggested for the identification of Rh-negative patients requiring anti-D gamma-globulin to prevent sensitization.

Development of serum and intestinal antibody response to rotavirus after naturally acquired rotavirus infection in man.

The temporal characteristics of the response of rotavirus specific IgM, IgG, IgA in serum and secretory antibody in feces to rotavirus were studied in 77 hospitalized patients with rotavirus induced gastroenteritis. The response in serum was characterized by the sequential appearance of rotavirus specific IgM, IgG, and IgA antibody. The IgM antibody appeared to be higher in the acute phase of the disease and was subsequently replaced by the IgG and IgA antibodies. However, the titers of IgG rotavirus antibody in convalescent specimens of serum were found to be statistically significantly lower in patients with severe or prolonged rotavirus infection than in specimens from subjects with mild or moderate disease. Most fecal specimens collected during both the acute and convalescent phase of illness contained virus specific secretory IgA. Higher concentrations of antibody were measured in convalescent samples from patients with prolonged diarrhea and virus shedding. These observations suggest a possible relationship between the severity of rotavirus infection and the nature of systemic and secretory antibody response.

Sequential determination of serum human placental lactogen, estriol, and estetrol for assessment of fetal morbidity.

Serial measurements were made of the concentrations of maternal serum human placental lactogen (hPL) (300 determinations), estriol (E3) (460 determinations), and estetrol (E4) (275 determinations) in normal human pregnancy during the third trimester period. Simultaneous determinations of serum hPL, E3, and E4 were also made sequentially on blood samples from 6 diabetic and 5 toxemic pregnant women to ascertain the relative usefulness of these parameters as indicators of fetal welfare. In uncomplicated diabetic patients controlled with insulin, all parameters increased with gestational age. In three pregnancies complicated by severe toxemia in which fetal distress progressed to intrauterine fetal death, both serum E3 and E4 levels decreased progressively, but E4 concentration started to decrease at least 1 day earlier than E3 prior to fetal death. In other women, the E4 levels appeared to drop or decrease significantly whereas the E3 levels remained almost unchanged. Daily hPL levels remained low in chronic fetal distress and, therefore, appeared to be of minimal value for predicting either intrauterine death or acute fetal distress. Therefore, serum E4 measurement seems to provide a more sensitive and reliable indicator of fetal morbidity than the measurement of serum E3 during toxemic pregnancies.

Immunoaffinity chromatography of human beta-hexosaminidase A.

A highly specific method for the purification of human beta-hexosaminidase A employing immunoaffinity chromatography is described. Using an antiserum against the unique antigenic determinant, alpha, of beta-hexosaminidase A, and elution with 8.0M urea, a 283-or 417-fold purification of the enzyme was obtained in a single step from crude human placental homogenate.