PubMed HealthSearch

Biomedical subjects

D Rush

Publications and source records attributed to D Rush.

At least 37 records · Page 2Linked to original sources

Fleroxacin pharmacokinetics in aqueous and vitreous humors determined by using complete concentration-time data from individual rabbits.

Although composite data from separate subjects can be used to generate single-subject estimates, intersubject variation precludes rigorous ocular pharmacokinetic analysis. Therefore, a rabbit model in which sequential aqueous and vitreous humor samples were obtained following the administration of the quinolone fleroxacin was developed. Mean data from individual animals were used for pharmacokinetic analysis. Following direct intravitreal or systemic drug administration, sequential paracenteses did not alter pharmacokinetic constants or ocular penetration and were not associated with an increase in ocular protein; contamination of vitreous humor with blood was minimal (less than 0.1%). Following direct injection or intravenous administration, vitreous humor concentration-time data were best described by one- and two-compartment models, respectively. The maximum concentration and the penetration into the aqueous and vitreous humors were 1.54 and 0.5 micrograms/ml and 27 and 10%, respectively. Elimination rates from aqueous and vitreous humors and serum were similar following parenteral drug administration. Drug elimination following direct injection was rapid, and the elimination rate from the vitreous humor was not prolonged by the coadministration of probenecid. Our animal model provides a new approach to the rigorous examination of the ocular pharmacokinetics of quinolone antimicrobial agents in the eye.

Animals

Dietary patterns of elderly Boston-area residents defined by cluster analysis.

The dietary patterns of 680 noninstitutionalized, predominantly white, elderly volunteers from the Boston area (447 women and 233 men) were examined by cluster analysis of food contribution to energy intake. Data were derived from 3-day dietary records. The four major patterns identified corresponded to high consumption of (a) alcohol, (b) milk, cereals, and fruits, (c) bread and poultry, and (d) meat and potatoes. The resulting clusters of subjects differed significantly in gender, education, income, and frequency of smoking. Those with diets high in milk, cereals, and fruits had the highest intakes of micronutrients and the best hematologic profile. Those with high meat and potato intakes had the lowest intakes of micronutrients and lowest levels of plasma folate and vitamin B-6. High alcohol consumers had lowest blood levels of riboflavin and vitamin B-12 and highest levels of high-density-lipoprotein cholesterol. Those with high bread and poultry intakes had lowest reported energy intakes, but, paradoxically, they had the highest mean body mass index. Neither total serum cholesterol nor cholesterol intake varied significantly among groups. Our findings suggest that the nutritional status of the elderly may be improved by promoting food patterns rich in milk, fruit, and cereals and by counseling the elderly to limit consumption of alcohol and meats high in saturated fats.

Aged

A multicenter study to evaluate a novel assay for quantitation of soluble interleukin 2 receptor in renal transplant recipients.

The clinical utility of monitoring soluble interleukin 2 receptor (sIL-2R) as an indicator of immune stimulation in renal transplant patients was evaluated in a retrospective study at 3 centers. Serum samples (n = 2360) were obtained from 86 (17 living related donor, 69 cadaver) transplant recipients. The patients had received either triple therapy (n = 35) or antilymphocyte antibody induction therapy followed by triple therapy (n = 51). The mean period of postoperative observation was 118 days (range, 6-349 days). Serum sIL-2R concentrations were quantitated by an automated microparticle enzyme immunoassay (MEIA) (Abbott Diagnostics) in which sIL-2R was captured by 7G7/B6 monoclonal antibody-coated microparticles and detected by an immunospecific rabbit antihuman sIL-2R-alkaline phosphatase conjugate. A distinct advantage of the technique was rapid turn-around time: 1-24 results were obtained in less than 50 min. Cyclosporine trough concentrations were determined by radioimmunoassay or high-performance liquid chromatography. Diagnosis of rejection was established by clinical and histological criteria. The mean sIL-2R concentration in patients receiving antilymphocyte antibody induction therapy increased from 3486 +/- 1729 U/ml (+/- SD) at the time of transplant to a maximum of 7395 +/- 7101 U/ml on the third day posttransplant; this increase was not observed in patients receiving triple therapy (P less than 0.0001). By the sixth day of posttransplant, there were no differences in sIL-2R levels in the two groups. Fifty rejection episodes were observed in 29 patients on triple therapy. The mean sIL-2R concentration rose from 3022 U/ml at the data point prior to rejection to 3524 U/ml at the time of rejection. Thirty-four rejection episodes were observed in 26 patients receiving induction therapy. The mean sIL-2R concentration was 3015 U/ml at the data point prior to rejection and 4815 U/ml at the time of rejection. The sIL-2R concentrations began increasing earlier and rose higher in rejecting patients who received induction therapy than in those receiving triple therapy. Early posttransplant sIL-2R levels increased significantly more in cadaver recipients than in LRD recipients, reaching a maximum on day 2 posttransplant (P less than 0.001). Prerejection sIL-2R concentrations were significantly lower in LRD recipients than in cadaver recipients (2248 U/ml vs. 4290 U/ml, P less than 0.02), as were sIL-2R levels at the time of diagnosis of rejection (2800 U/ml vs. 4832 U/ml, P = 0.01). The mean sIL-2R level in stable long-term graft recipients was 2110 U/ml, with approximately 90% of values less than 3000 U/ml.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent

Pharmacokinetics of amikacin and chloramphenicol in the aqueous humor of rabbits.

Composite data describing ocular pharmacokinetics are unreliable because of intersubject variation. To address this problem, an animal model was developed in which multiple aqueous samples from single subjects were obtained. Following direct anterior chamber or intravenous administration of amikacin or chloramphenicol, pharmacokinetic analysis of drug concentrations in the serum and anterior chamber was performed by using a nonlinear least-squares regression program. The number of anterior chamber paracenteses performed did not alter the beta elimination rates or percent penetration into the anterior chamber. The aqueous humor and peripheral-compartment terminal slopes were identical. These data indicate that complete ocular concentration-time curves can be obtained without altering antibiotic pharmacokinetics. Following direct injection into the anterior chamber, the elimination rates for both antibiotics followed a one-compartment model, whereas those following intravenous administration best fit an open, first-order, two-compartment model. Following intravenous administration, the anterior chamber elimination rate constants for both drugs were equal to that of the serum and significantly longer than that following direct injection. The elimination rates of both drugs following direct injection were similar. Systemic administration resulted in drug levels in aqueous humor that persisted longer than those following direct injection. Chloramphenicol, a lipophilic compound, gave higher mean concentrations in aqueous humor than did amikacin. Our model provides a new approach which rigorously examines ocular pharmacokinetics and provides data which suggest that for selected compounds the parenteral route of administration is preferable.

Amikacin

Recent declines in breast-feeding in the United States, 1984 through 1989.

Ongoing surveys performed by Ross Laboratories demonstrate recent declines both in the initiation of breast-feeding and continued breast-feeding at 6 months of age. Comparing rates in 1984 and 1989, the initiation of breast-feeding declined approximately 13% (from 59.7% to 52.2%), and there was a 24% decline in the rate of breast-feeding at 6 months of age (from 23.8% to 18.1%). The decline in breast-feeding was seen across all groups studied but was greater in some groups than in others. Logistic regression analysis indicates that white ethnicity, some college education, increased maternal age, and having an infant of normal birth weight were all positively associated with the likelihood of both initiating breast-feeding and continuing to breast-feed to at least 6 months of age. Women who were black and who were younger, no more than high school educated, enrolled in the Women, Infants and Children supplemental food program, working outside the home, not living in the western states, and who had an infant of low birth weight were less likely either to initiate breast-feeding or to be nursing when their children were 6 months of age. The factors influencing the decline in breast-feeding were not uniform. There were fewer sociodemographic factors associated with the decline in the initiation of breast-feeding than in the decline in prolonged breast-feeding. While the disparity between older and younger mothers in initiating breast-feeding increased, there was an offsetting trend as the disparity associated with parity decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight

Maternal cigarette smoking during pregnancy, adiposity, social class, and perinatal outcome in Cardiff, Wales, 1965-1977.

There have been several reports in which maternal nutritional status has been implicated as either a mediating or moderating factor in the relationship between maternal cigarette smoking and birthweight and perinatal survival. Also, there is evidence that the effects of maternal cigarette smoking on both intrauterine growth and fetal viability are more intense among women of lower social status. The well-maintained data set of the Cardiff Births Survey from 1965-1977 afforded an opportunity to review these issues among over 50,000 births in south Wales (the survey took place in Cardiff City through 1973 and subsequently included suburban areas of South Glamorgan). The major findings were: (1) Smoking was much more common with descending maternal social status; (2) among upper status women, smokers had similar or slightly greater mean Quetelet's indices (kg/m2) than nonsmokers. Among lower status women, smokers were considerably thinner than nonsmokers; (3) the greater the adiposity of the mother, the less the association between cigarette smoking and depressed birthweight; (4) perinatal mortality was significantly higher among heavy smokers (10 or more cigarettes a day) than among nonsmokers; and (5) neither the decrease in birthweight nor the excess mortality associated with smoking was greater among those of lower rather than upper social status, except among class I women, among whom smoking was only minimally associated with depressed birthweight. With the inclusion of the South Glamorgan suburban population in the survey after 1974, the excess mortality associated with heavy smoking dropped from 53 to 16%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Epidemic of nosocomial Legionnaires' disease in renal transplant recipients: a case-control and environmental study.

An outbreak of Legionella pneumophila pneumonia occurred in 6 of 49 new renal transplant recipients over the course of 13 months. We compared infected patients (cases) and uninfected patients (controls) with respect to potential risk factors. Corticosteroid use, need for hemodialysis and number of days of hemodialysis were significantly greater among the cases. Logistic regression analysis identified corticosteroid dosage and number of days of hemodialysis as independent risk factors. Lymphopenia and monocytopenia were correlated with the amount of corticosteroid administered and occurred to a greater degree in the cases. All clinical isolates were of L. pneumophila serogroup 1, subtype Philadelphia 1, which was also cultured from a recovery room sink outside the operating room where the transplants were done. Other areas of the hospital were colonized with other, heterogeneous strains of L. pneumophila. The organism was not eliminated from the hospital water supply despite shock chlorination and superheating of water tanks. The epidemic ended when new transplant recipients routinely received prophylactic trimethoprim-sulfamethoxazole (160-800 mg given orally once daily) while in hospital after transplantation. Corticosteroid-induced monocytopenia and lymphopenia and the complement activation and monocyte depletion effects of hemodialysis may combine to increase susceptibility to Legionnaires' disease.

Adult

Exposure to passive cigarette smoking and child development. A critical review.

Past studies relating smoking during pregnancy (and afterwards) and later child development are critically reviewed. There are consistent deficits among offspring of smokers in stature, cognitive development and educational achievement, as well as more frequent problems of temperament, adjustment, and behavior, particularly abnormally high levels of activity and inattention. The meaning of these relationships remains obscure, since it cannot be assumed that these abnormalities of child development are caused by parental cigarette smoking. In most studies there has been relatively little attention paid to the potential confounding by social, demographic, and psychological differences between smokers and nonsmokers. It is thus essential to carefully balance the comparative impact of social and environmental influences that may be different between families of smokers and nonsmokers, versus the toxic effects of tobacco.

Adolescent

Parental smoking and post-infancy wheezing in children: a prospective cohort study.

The contribution of parental smoking to wheezing in children was studied in a subset of all British births between April 5 and 11, 1970 (N = 9,670). Children of smoking mothers had an 18.0 per cent cumulative incidence of post-infancy wheezing through 10 years of age, compared with 16.2 per cent among children of nonsmoking mothers (risk ratio 1.11, 95% CI: 1.02, 1.21). This difference was confined to wheezing attributed to wheezy bronchitis, of which children of smokers had 7.4 per cent, and those of nonsmokers had 5.2 per cent (risk ratio 1.44, 95% CI: 1.24, 1.68). The incidence of wheezy bronchitis increased as mothers smoked more cigarettes. After multiple logistic regression analysis was used to control for paternal smoking, social status, sex, family allergy, crowding, breast-feeding, gas cooking and heating, and bedroom dampness, the association of maternal smoking with childhood wheezy bronchitis persisted. Some of this effect was explained by maternal respiratory symptoms and maternal depression, but not by neonatal problems, the child's allergic symptoms, or paternal respiratory symptoms. There was a 14 per cent increase in childhood wheezy bronchitis when mothers smoked over four cigarettes per day, and a 49 per cent increase when mothers smoked over 14 cigarettes daily.

Bronchitis

Defining cellular senescence in IMR-90 cells: a flow cytometric analysis.

Using multiparameter flow cytometric analysis, we find that senescent cells accumulate in a unique cell-cycle compartment characterized in cell-cycle arrest in G1 and a significantly reduced nucleocytoplasmic ratio (genome size/cell mass) relative to cycling cells. With respect to gross cellular phenotype, the quiescent state of senescent cells differs from quiescence induced by density inhibition; the former is associated with a reduction in the nucleocytoplasmic ratio, while the latter is associated with an increase in the nucleocytoplasmic ratio. Senescent cells were present at all passages examined. The frequency of senescent cells was low in early-passage cultures and increased with passage number. Senescence of populations of IMR-90 cells reflects change in the relative frequency of these cells. The frequency of cells with karyotypic changes increased with the progressive accumulation of out-of-cycle cells.

Cell Cycle

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. II. Review of past studies of WIC.

We reviewed past work relating WIC benefits to birth weight, perinatal and infant survival, anemia, child growth, and dietary intake. Despite many uncertainties, the probable range of reduction in the rate of low birth weight was approximately 1-2% and the increase in mean birth weight ranged from 0 to approximately 60 g. There was too little information to securely estimate effects of WIC on perinatal and infant mortality nor on the dietary intake of women or children. Although the number of studies was small, there probably were important effects of WIC on rates of childhood anemia. There is too little evidence to come to any conclusion on effects during pregnancy. There is little evidence that the WIC program has affected children's linear growth.

Birth Weight

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. III. Historical study of pregnancy outcomes.

We related perinatal outcome and quality of prenatal care between 1972 and 1980 to WIC benefits to pregnant women among 11,154,673 births in 1392 counties in 19 states and the District of Columbia, adjusted for time change and between-county variability. WIC was associated with increased first trimester prenatal care (4.1%, p less than 0.001), decreased inadequate prenatal care (-5.0%, p less than 0.001), longer duration of gestation (0.20 d, p less than 0.05), decreased preterm delivery (-0.92%, p less than 0.05) and increased birth weight (23 g, p less than 0.01). After autocorrelation was accounted for, significance levels for birth weight and frequency of preterm delivery were 0.05 less than p less than 0.10. Including counties with incomplete time series data, the estimated effect on birth weight was 23.9 g (p = 0.004) and on decreased fetal mortality was -2.3/1000 (p = 0.04). Among those with less than 12 y schooling, whites had a 1.8% reduction in preterm birth (p less than 0.05) and blacks a 2.0% reduction (p less than 0.05). The estimated effect on birth weight for less-educated whites was 46.6 g (p less than 0.001). The predominant effects of WIC were on improved physiologic status of the mother and fetus.

Black or African American

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. IV. Study methodology and sample characteristics in the longitudinal study of pregnant women, the study of children, and the food expenditures study.

The longitudinal study of pregnant women enrolled a national probability sample of 5,205 women first certified for WIC and 1,358 comparable low-income pregnant women in 174 WIC clinics located in 58 areas in the contiguous 48 states and in 55 prenatal clinics without WIC programs in counties with low program coverage. The women completed 24-h dietary recalls, histories of food expenditures, health care utilization, health and sociodemographic status, and anthropometric assessment. At late-pregnancy follow-up 3,967 WIC and 1043 control women were interviewed and 853 WIC and 762 control women completed 1-wk food expenditure diaries. Birth outcome was abstracted (from hospital records) for 3,863 WIC and 1058 control women. Anthropometry, dietary intake, health, and use of health services were related to WIC among 2,619 random low-income preschoolers. Psychological development was assessed in 526 children aged 4 and 5 y. Control women had higher income, education, and employment status; therefore, WIC program benefits probably were underestimated.

Child Nutritional Physiological Phenomena

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. V. Longitudinal study of pregnant women.

The major associations with the Special Supplemental Food Program for Women, Infants, and Children (WIC) in pregnancy were increased intake of protein, iron, calcium, and vitamin C (four of five targeted nutrients) and of energy, magnesium, phosphorus, thiamin, riboflavin, niacin, vitamin B-6, and vitamin B-12; reversal of low weight gain in early pregnancy; smaller fat stores in late pregnancy; reduced frequency of premature rupture of the uterine membranes; larger infant head circumference with no effect on birth weight and length; increased birth weight and head circumference with better program quality; and lower fetal mortality of appreciable but not significant magnitude. Incremental energy intake was comparable to that in most small-scale supplementation trials. There was no evidence of effects on frequency of prenatal care, use of alcohol or tobacco, the intention to breast-feed, or the rate of breast-feeding. Maternal alcohol intake was associated with depressed infant head circumference, over and above effects on birth weight and length.

Anthropometry