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J M Foster

Publications and source records attributed to J M Foster.

11 recordsLinked to original sources
PubMed1992

Analysis of ecdysteroids in the trematodes, Schistosoma mansoni and Fasciola hepatica.

Adult Schistosoma mansoni from experimentally infected mice and Fasciola hepatica recovered from ovine livers post mortem were analyzed for free and conjugated ecdysteroids by radioimmunoassay, high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by capillary gas chromatography/mass spectrometry (selected ion monitoring). Both species contained ecdysone and 20-hydroxyecdysone as free ecdysteroids and as polar conjugates. F. hepatica also contained a polar conjugate of 2-deoxyecdysone. Evidence of apolar ecdysteroid conjugates was only obtained for F. hepatica. The free ecdysteroid-containing fraction of S. mansoni contained small amounts of unidentified immunoreactive material.

Animals↗
PubMed1990

Hyperoxia potentiates Ureaplasma urealyticum pneumonia in newborn mice.

The effect of continuous exposure to 80% oxygen on newborn mice with Ureaplasma urealyticum pneumonia was determined. Mice were inoculated intranasally with either U. urealyticum or sterile broth and then housed in either 80% oxygen or room air (21% oxygen). The mice were sacrificed at either 7 or 14 days after inoculation. Significantly more mice in the U. urealyticum group housed in 80% O2 than in the room air-exposed group were culture positive 14 days after inoculation (P = 0.042), but no difference was found at 7 days. The presence of alveolar macrophages, neutrophils, and lymphocytes and alveolar wall thickness were determined. Overall, the group housed in 80% O2 and inoculated with U. urealyticum had severe pulmonary lesions at both time points, while the lesion severity in the room air-exposed group inoculated with U. urealyticum and the group housed in 80% O2 and inoculated with sterile broth was dependent on the time point. Mortality was significantly higher in the group housed in 80% O2 and inoculated with U. urealyticum than it was in all other groups (P less than 0.001). Our results indicate that hyperoxia causes the persistence of U. urealyticum in the lungs of newborn mice, acutely potentiates the inflammatory response, and turns an otherwise self-limited pneumonia into a lethal disease.

Animals↗
PubMed1989

Prematurity, postdates, and growth retardation: the influence of use of ultrasonography on reported gestational age.

The preterm and postterm delivery rates and the percentage of infants with intrauterine growth retardation are dependent on the gestational age recorded at delivery. At our institution a sharp increase in the preterm delivery rate and a coincident decrease in the postterm delivery rate and the rate of intrauterine growth retardation were noted. Over a 3-year period, while the characteristics of the obstetric population changed only slightly, the gestational age distribution shifted, with a decrease in the mean gestational age of about 1 week and a risk in the reported preterm delivery rate from 12% to 17%. About 15% of this rise was explained by an increase in obstetric interventions, and another 15% can be explained by changes in the way physicians rounded off gestational age. The majority of the increase in the preterm delivery rate was related to changes involving ultrasonographic examinations. These changes included a greater percentage of the population examined, trends toward earlier examinations, a tendency for the physicians to use ultrasonography rather than the last menstrual period in choosing the final gestational age, the use of different standards, an increase in the number of structures measured, and the weight given to various structures for determination of gestational age. It is apparent that changes in use of ultrasonography had a profound effect on the reported gestational age distribution at our institution.

Birth Weight↗
PubMed1989

Intrauterine growth retardation: standards for diagnosis.

An intrauterine growth-retarded infant is commonly defined as one weighing less than the 10th percentile in birth weight for its gestational age. However, because there is no standard population from which to derive these percentiles, the birth weights that serve as the cutoff point in various published studies may differ by several hundred grams at any gestational age. For this reason, we examined the studies from which the currently used 10th-percentile standards are derived to determine which factors may be responsible for the variation. In addition to obvious differences in the populations and geographic areas on which they were based, studies differed in how gestational age was determined, whether the gestational age was "rounded" or given in completed weeks, which types of infants were excluded, whether the studies were hospital or population based, and whether they were controlled for sex of the infant and race and parity of the mother. These differences in study methodology may be as or more important than the population differences in defining the 10th percentile cutoffs. A single national standard for intrauterine growth retardation would allow comparison between studies of risk factors, diagnostic tests, management, and long-term follow-up status of fetuses and infants with intrauterine growth retardation.

Birth Weight↗
PubMed1989

Maternal serum alpha-fetoprotein prenatal screening for Down syndrome.

The relationship between maternal serum alpha-fetoprotein (MSAFP) levels, maternal age and Down syndrome risk factors were studied in the greater Birmingham and North Alabama areas. After adjustment for race and maternal weight, 3.84 percent of women in this study were determined to have Down syndrome risk factors equal to or greater than that of a 35 year old woman with a normal pregnancy. Maternal weight adjustment was of special importance, reducing the number of MSAFP values considered low from 5.12 percent to 3.40 percent. The use of race and area specific medians was also important in the use of prenatal MSAFP screening for Down syndrome affected pregnancies.

Body Weight↗
PubMedDate not supplied

Investigations on N-nitrosopyrrolidine in dry-cured bacon.

Dry-cured or "country-style" bacon is a low volume specialty product typically made by small producers whose production practices vary widely. These practices include the direct application of dry-cure formulations containing varying concentrations of salt, sugar, flavoring agents, sodium nitrite, and sometimes sodium nitrate, and the use of lengthy curing and processing times. Because of the possibility of generating higher levels of N-nitrosopyrrolidine (NPYR) after frying in this product type compared with pump-cured bacon, an investigation was carried out on dry-cured bacon obtained from cooperating state or federally inspected establishments. Three different samples from each of the 16 plants were analyzed. Only one sample from each of 2 different producers exceeded the Food Safety and Inspection Service (FSIS) action level of 17 ppb NPYR, indicating that the majority of samples tested were in compliance. A significant correlation (P less than 0.01) was found between residual NaNO2 prior to frying and NPYR after frying. The elimination of added nitrate in the dry-cure formulations is recommended.

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