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Biomedical subjects

R D Johnson

Publications and source records attributed to R D Johnson.

226 records · Page 13Linked to original sources
PubMedDate not supplied

Activities of alkaline phosphatase in first trimester chorion biopsy tissue.

We have determined the activity of alkaline phosphatase in chorionic villous tissue obtained in the first trimester of pregnancy, in order to obtain the normal range of values as a prerequisite for application to the prenatal diagnosis of the rare bone disease hypophosphatasia. The activities found were a combination of intestinal and liver/bone/kidney types; traces of placental type were present in only one sample.

Alkaline Phosphatase↗
PubMedDate not supplied

Effect of Maalox on the oral absorption of sparfloxacin.

Sparfloxacin is a broad-spectrum oral fluoroquinolone antimicrobial agent with a long elimination half-life (t(1/2)). Concurrent treatment with antacids has demonstrated a reduction in the oral absorption of many quinolones. This study was undertaken to determine an optimal time for dosing antacids in relation to sparfloxacin administration to minimize antacid-induced reduction in sparfloxacin bioavailability. This open-label, single-dose, randomized, four-way crossover study was conducted in 20 healthy male volunteers between the ages of 18 and 38 years. Treatments consisted of single 400-mg oral doses of sparfloxacin alone and with Maalox 30 mL given 2 hours before, 2 hours after, and 4 hours after oral administration of sparfloxacin. All 20 subjects completed the study. A 400-mg single oral dose of sparfloxacin was well tolerated both given alone and with Maalox. Maalox given 4 hours after sparfloxacin administration was the only regimen that did not cause a statistically significant reduction in the rate and extent of sparfloxacin absorption. The 90% confidence intervals comparing sparfloxacin alone with the preceding regimen in terms of area under the concentration-time curve from zero to infinity (AUC(0-infinity)) and maximum plasma concentration (Cmax) were within the range 80% to 125%. Administration of Maalox 2 hours before, 2 hours after, and 4 hours after sparfloxacin caused mean decreases in AUC(0-infinity) of 23%, 17%, and 5%, respectively. Corresponding decreases in mean Cmax values were 29% with Maalox administered 2 hours before sparfloxacin and 13% with Maalox administered 2 hours after sparfloxacin. The mean Cmax value was un affected when Maalox was administered 4 hours after sparfloxacin administration. The 90% confidence intervals for these comparisons with sparfloxacin alone were outside the 80% to 125% range and did not include 100%. Time to Cmax and t(1/2) were similar for all four regimens. The elimination rate of sparfloxacin was unaffected by concomitant administration with Maalox in healthy male volunteers.

Adolescent↗
PubMedDate not supplied

Current status of radiologically directed pulmonary thin needle aspiration biopsy. An analysis of 200 consecutive biopsies and review of the literature.

The results of 200 consecutive pulmonary thin needle aspiration biopsies (TNAB) are presented. A diagnostic yield of 89.5 percent was obtained, with 5.5 percent of biopsies insufficient for diagnosis. There were six (3 percent) false negative biopsies and one (0.5 percent) false positive biopsy. The predictive value of positive result was 99.2 percent. The predictive value of a negative result was 90.8 percent. Cytologic examination correctly classified 72.1 percent of primary pulmonary carcinomas. The major complication was pneumothorax which occurred in 33.5 percent of TNAB. Techniques for improving the reliability of TNAB diagnosis are discussed, and pertinent literature is reviewed.

Biopsy, Needle↗
PubMedDate not supplied

Pesticide, heavy metal, and other chemical residues in infant and toddler total diet samples. (III). August 1976-September 1977.

The Total Diet Study has been conducted by the Food and Drug Administration, U.S. Department of Health and Human Services, since 1964 to monitor the diet of adults, and more recently the infant and toddler diet, for residues of pesticides and other chemicals. This report presents the residues found in 12 infant and toddler market baskets, i.e., items comprising the average 2-week diet of infants and toddlers, collected in 12 major cities in 4 geographical areas from August 1976 through September 1977. The analyses for each market basket were performed on composites of each of 11 food classes, and the results are presented in a variety of formats. In addition to chemical residues, the market baskets were also analyzed for 6 heavy metals: arsenic, lead, selenium, zinc, cadmium, and mercury. Results of recovery studies conducted with residue compounds of various types are also included in this report. The results for the adult market baskets for the same period are published as a separate report.

Animals↗
PubMedDate not supplied

Pesticide, metal, and other chemical residues in adult total diet samples. (XIII). August 1976-September 1977.

Since 1964, the Food and Drug Administration has reported residues of pesticides and other chemicals in the average diet of the United States' heartiest eater, the young adult male, through the Total Diet Study. This report is the thirteenth in the series and includes results of analyses for 25 market basket samples collected from August 1976 through September 1977 in 20 different cities throughout 4 geographical areas. All food items were divided into 12 different composite food classes, and 25 composites, 1 from each market basket, were prepared and analyzed for each food class. Averages and ranges of pesticide and chemical residues are presented in various formats, together with results for the following heavy metals: zinc, cadmium, lead, mercury, arsenic, and selenium. Individual items making up the dairy composites and the meat-fish-poultry composites were analyzed separately for 4 market baskets and are presented as a part of this report. Recovery studies of pesticides and chemicals added to each of the various food classes are also included.

Adult↗