Search PubMed⌕ Search

Biomedical subjects

A Ross

Publications and source records attributed to A Ross.

At least 127 records · Page 7Linked to original sources
PubMed1995

Maternal HIV infection, drug use, and growth of uninfected children in their first 3 years.

OBJECTIVE: To determine the separate effects of maternal HIV infection and drug use during pregnancy on growth of uninfected children in their first 3 years. DESIGN: Retrospective analysis of measurements from health visitor records made during routine child health surveillance at 6 weeks, 10 months, and 3 years of age. Multilevel analysis allowed for between-infant variation in fitted growth lines, and adjustment for other factors. Growth was described in terms of an intercept (z score at term) and growth slopes (change in z score per year) up to, and from, 4 months. SUBJECTS: 290 case babies delivered in Edinburgh hospitals to women who reported injection drug use by either themselves or their HIV infected partner, and 186 community controls. A total of 131 (45%) of the case babies were born to women who used drugs, predominantly opiates, during pregnancy and 93 (32%) to HIV infected women. The eight infected children were excluded from analysis. MAIN OUTCOME MEASURES: Age and sex standardised z scores for height, weight, and body mass index. RESULTS: 459 (96%) of the 476 records for cases and controls were traced, yielding 1432 weight and 939 height measurements. Maternal HIV infection was not found to affect growth; at 3 years the estimated effect on weight z score was 0.16 with 95% confidence interval (-0.25 to 0.57) and for height 0.18 (-0.19 to 0.55). Drug use during pregnancy was associated with lighter babies at 40 weeks followed by depressed growth in the first four months, these infants remaining just slightly smaller at 3 years with an estimated effect on z scores of -0.5 for weight with 95% confidence interval (-0.89 to -0.11) and -0.37 (-0.72 to -0.02) for height. CONCLUSIONS: Maternal HIV infection does not adversely affect growth in uninfected infants, and the effect of drug use during pregnancy is limited to small decrease in size at 3 years.

Body Height↗
PubMed1995

Continuous versus bilevel positive airway pressure for obstructive sleep apnea.

Recent objective studies demonstrate relatively low hours of nightly use during nasal continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea (OSA). Patients frequently complain of dyspnea or discomfort during CPAP use, especially during expiration (against the continuous pressure), which may be a reason for the low hours of use. We hypothesized that with decreased expiratory pressure, hours of nightly use would increase. Therefore, we randomized 83 OSA patients to receive either continuous or bilevel positive airway pressure when expiratory pressure is lower. To document objectively the effective use of either therapy, we built and installed elapsed-time and mask pressure sensors in the patients' positive airway pressure units. A total of 62 patients were evaluable and followed for 1 yr. Of these, 26 received bilevel and 36 CPAP pressures. The machine timers measured accumulated "machine-on" time, and the mask pressure sensor recorded the total time in which the mask pressure was within 2 cm H2O of the effective pressure (pressure shown to eliminate 95% of the obstructive apneas during a full night of polysomnography). The mean machine timer hours of CPAP were 5.0 +/- 0.19 SEM and 4.9 +/- 0.23 SEM during bilevel therapy (p NS) over a 12-mo period. The pressures required during CPAP or bilevel therapy were not different between high and low hourly users. Effective use, the percentage of time that the machine was running and the prescribed pressure was being delivered, was 80% in CPAP and 82% in the bilevel users (p NS). Both groups had equal complaints with regard to mask discomfort, machine noise, and nasal stuffiness.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1995

The dilemma of managing value.

"Value" is an elusive term, but talk of how to manage value raises the specter of chaos. Value is defined as a working equation involving appropriateness of care, quality of outcomes and service, and cost. One hypothesis is that purchasers and providers will ultimately recognize that the value of health care services provided is critical because value, properly managed, directly addresses the volatile issue of containing health care costs. But to achieve success in managing value, providers must initiate new strategies and transform organizational and clinical priorities and practices. As the contest intensifies between society's infinite demand for health care services and finite resources, the need to truly subscribe to the management of value will become ever more important. Those providing care will learn to appreciate that long-term success will depend on much more than mere cost cutting.

Cost Control↗
PubMed1995

HIV prevalence and risk factors in university students.

OBJECTIVE: To estimate HIV prevalence and risks in university students. DESIGN: Anonymous self-completion questionnaire and HIV survey with saliva samples. SETTING: University students at matriculation. PARTICIPANTS: All first and third year undergraduates and newly registering postgraduates at the University of Edinburgh, Scotland. MAIN OUTCOME MEASURES: HIV prevalence, sexual behaviour, condom use, drug use. RESULTS: The questionnaire responses were used to classify the 4665 respondents into four groups, ordered by risk of HIV positivity, and a sample of 2041 was selected for testing. All of the top two risk groups were tested (217 and 758 tests, respectively) as well as a random sample of the others. Five positive HIV-antibody tests were detected, all from the highest risk group. This gives an estimated rate of 1.2 per 1000 (95% confidence interval, 0.4-2.9) for all respondents. Only one of the five HIV-positives had been tested for HIV. The factors associated with HIV positivity were residence in Africa, intravenous drug use and male homosexuality. Overall, 74% of respondents reported ever having had sexual intercourse and this rate was the same for men and women. Reported intravenous drug use was very low: 0.5% for men and 0.1% for women. Condom use was more common for partners of short acquaintance, but unrelated to the number of sexual partners in the last year. CONCLUSIONS: There was no evidence of the spread of HIV infection beyond known high-risk groups in this population. This may be a result of relatively low levels of HIV risk-taking behaviour in the majority of respondents.

Adult↗
PubMed1995

HIV infection in women: immunological markers and the influence of pregnancy.

OBJECTIVE: To describe the influence of pregnancy on immunological marker paths and progression of HIV-infected women. DESIGN: Analysis of prospectively collected immunological and clinical data collected on 145 women reviewed at the City Hospital, Edinburgh, between 1985 and 1992 using a two-level random-effects model that allows for within- and between-patient variance. RESULTS: There were differences between the marker paths of women according to risk activity; women who had acquired HIV via injecting drug use (in addition to heterosexual intercourse) had a higher level of absolute CD4 cells, CD4% and total lymphocytes at seroconversion than those who had acquired HIV via heterosexual intercourse alone; however, immunological markers declined more steeply after seroconversion. There was no evidence that pregnancy, either before or after HIV seroconversion had an adverse effect on marker paths of HIV disease. There was a significant association between pregnancy after HIV seroconversion and post-pregnancy changes in immunological markers: an increase in the CD4% and a decrease in CD8%. However, causality cannot be implied as pregnancy itself may be associated with considerable lifestyle changes. During pregnancy the total white blood count rose due to an increase in the number of granulocytes, whereas the total lymphocyte numbers fell. The absolute CD4 lymphocyte subset counts fell progressively but the effect was due to the fall in the total lymphocyte counts, there being no influence of pregnancy on either CD4% or CD8%. CONCLUSIONS: In asymptomatic HIV infection, changes in the absolute levels of CD4 and CD8 lymphocyte counts are primarily related to changes in the other components of the white cell count because there were no changes in CD4% and CD8%. Pregnancy itself has no adverse effect on immunological markers of HIV.

Adult↗
PubMed1994

Structure and dynamics of the human granulocyte colony-stimulating factor determined by NMR spectroscopy. Loop mobility in a four-helix-bundle protein.

Recombinant 15N- and 13C-labeled human granulocyte colony-stimulating factor (rh-metG-CSF) has been studied by 2D and 3D NMR using uniformly labeled protein, as well as residue-specific 15N-labeled samples. Assignment of 90% of the backbone resonances and 85% of side-chain resonances has enabled the determination of both the secondary and tertiary structures of the protein. The fold is similar to those of the human growth hormone and other growth factors. Four stretches of helices were identified between residues 11 and 41 (helix A), 71 and 95 (helix B), 102 and 125 (helix C), and 145 and 170 (helix D), which form a left-handed four-helix bundle with helices A and B aligned parallel to one another (up-up) and antiparallel to helices C and D (down-down). An additional short fifth helix (E) is part of the AB loop connecting helices A and B. Examination of the protein's relaxation behavior, based on the model-free approach of Lipari and Szabo, shows that the G-CSF backbone has a well-defined structure of limited conformational flexibility in helices. In contrast, the long loop connecting helices C and D exhibits substantial fast internal motion compared to the overall rotational correlation time of the whole molecule, which is on the order of 13 ns.

Chemical Phenomena↗
PubMed1994

Structural and dynamic properties of the Fv fragment and the single-chain Fv fragment of an antibody in solution investigated by heteronuclear three-dimensional NMR spectroscopy.

Fv fragments, heterodimers of the variable light (VL) and variable heavy chain (VH) domains, are the smallest functional antibody units with molecular masses of approximately 26 kDa. The structural and dynamic properties of the Fv fragment and the corresponding single-chain Fv fragment (scFv: VH-linker-VL, 252 amino acids) of the phosphorylcholine-binding antibody McPC603 in the presence of hapten have been studied in solution by heteronuclear multidimensional NMR spectroscopy. Both 15N TOCSY-HMQC and triple-resonance experiments (HNCA and HN(CA)H, with 15N-13C-labeled protein) gave poor spectra, due to short T2 relaxation times for most of the backbone 1H, 15N, and 13C alpha atoms. The assignment procedure therefore relied upon the combination of amino acid and domain (VL) specifically labeled spectra and the 3D NOESY-HMQC spectrum of the uniformly 15N labeled Fv and scFv fragments. Approximately 80% of the 15N and 1H backbone and 60% of the 1H side-chain resonances have been assigned. Short- and long-range NOEs were used to determine the extent of beta-sheet structure and were compared to the X-ray crystallographic data. The 1H-15N NOE data indicate that the scFv backbone has a well-defined structure of limited conformational flexibility. However, the linker of the scFv fragment exhibits substantial fast internal motion (on the picosecond to nanosecond time scale) compared with the overall rotational correlation time of the whole molecule. Several residues in the CDRs, in turns, or at the C-terminal end of the protein have smaller NOEs, reflecting some degree of rapid motion in the protein backbone.

Amino Acid Sequence↗
PubMed1994

Do provider practices conform to the new pediatric immunization standards?

OBJECTIVE: Standards for pediatric immunization practices were issued by the Centers for Disease Control and Prevention, Atlanta, Ga, in May 1992. This article provides baseline data on immunization practices related to eight of the standards. DESIGN: Survey of pediatric providers before publication of the standards. SETTING: Baltimore, Md. PARTICIPANTS: Forty of the 41 health centers, clinics, and private practices serving children in designated high-risk census tracts participated in the survey. One hundred seventy-three of the 251 eligible physicians and nurse practitioners at the sites responded. MAIN OUTCOME MEASURES: Conformity with the eight standards was measured as a percentage of either sites or physicians and nurse practitioners across the sites. RESULTS: Conformity with the standards varied, ranging from nearly universal conformity with the need to educate parents and guardians about immunizations (standard 5) to less than 3% for simultaneous administration of all vaccine doses when a child is first eligible (standard 8). For most of the standards, considerable variability was found between and within public and private sites. CONCLUSIONS: Providers often followed practices that did not conform to the new standards (prior to issuance). Some of the standards are ambiguous and require clarification before they can be fully applied. The impact of the standards on immunization rates and pediatric primary health care has yet to be tested empirically.

Baltimore↗
PubMed1994

[Nutritional balance of the diet of the adult residents of Geneva].

Diet of the Swiss population has probably changed over the last 10 years, but these changes have not been recorded yet by nutritional studies. In the present study, 3 registered dieticians interviewed over the telephone 626 adults, resident of Canton Geneva, using a 24 hour recall. Interviews were performed during the 7 days of the week. Participants were randomly selected according to their age, sex and nationality. Participation was 80%. The following caloric (C) and nutritional intakes in proteins (P), lipids (L), carbohydrates (CH) and alcohol (A) were recorded: In non Swiss men: C = 2464 kcal/j., P = 16.2%, L = 32.4%, CH = 44.4%, A = 7.0%; in Swiss men: C = 2752 kcal/j., P = 15.3%, L = 34.0%, CH = 43.5%, A = 7.1%; in non Swiss women: C = 1897 kcal/j., P = 16.4%, L = 35.1%, CH = 46.5%, A = 2.4%; in Swiss women: C = 1865 kcal/j., P = 15.0%, L = 35.3%, CH = 46.0%, A = 3.2%. Total caloric intake and iron intake decreased with age. Older women ate less calcium than younger. In summary, the most important determinants of diet are age and sex. Proportion of lipids is relatively low in both men and women. Small differences related to nationality were observed in men.

Adult↗
PubMed1994

Thyroid function and thyroid size in normal pregnant women living in an iodine replete area.

OBJECTIVE: The interpretation of the changes in thyroid hormone concentrations during normal pregnancy is a matter of debate involving, in some geographical regions, enhanced thyroid activity in early pregnancy and a hypothyroid state in the third trimester. A clinically detectable increase in thyroid size has been found in areas of mild iodine deficiency ('goitre of pregnancy'), but not in iodine replete areas. DESIGN: A prospective study. We have studied thyroid size and function in normal pregnant women living in an iodine replete area. PATIENTS: Healthy women before and during a normal pregnancy resulting from artificial insemination (n = 10) and other women during the normal menstrual cycle (n = 11), in the iodine replete area of Amsterdam. MEASUREMENTS: Thyroid volume was measured by ultrasonography. Plasma T4, free T3, free reverse T3, TSH, thyroxine binding globulin, hCG, progesterone and thyroid autoantibodies were measured. RESULTS: Thyroid volume did not change during pregnancy (data given before pregnancy and during 1st, 2nd and 3rd trimesters, respectively: 10.3 +/- 5.1, 10.6 +/- 4.4, 9.6 +/- 3.8 and 9.4 +/- 3.0 ml, NS). Free T4 and free T3 levels declined during pregnancy (13.7 +/- 2.0, 13.5 +/- 4.1, 11.2 +/- 2.8, 10.2 +/- 1.6 pmol/l, P = 0.005; 4.55 +/- 0.63, 4.64 +/- 0.88, 3.72 +/- 0.67 and 4.01 +/- 0.75 pmol/l, P = 0.003), whereas free reverse T3 levels increased during pregnancy (0.16 +/- 0.04, 0.19 +/- 0.07, 0.14 +/- 0.03 and 0.20 +/- 0.07 pmol/l, P = 0.001). Thyroglobulin levels remained unchanged. Thyroid hormones and thyroid volume did not differ between follicular and luteal phases of the menstrual cycle. CONCLUSION: Thyroid volume does not increase during pregnancy in iodine-replete areas. The decrease in free T4 and free T3 and the increase in free reverse T3 concentrations during pregnancy resemble the changes in thyroid hormones seen in non-thyroidal illness. This could be a physiological adaptation enabling energy conservation during the high metabolic demands of pregnancy.

Environment↗
PubMed1994

Immunization coverage and its relationship to preventive health care visits among inner-city children in Baltimore.

OBJECTIVE: To provide empirical data on immunization coverage and the receipt of preventive health care to inform policy makers' efforts to improve childhood immunization. DESIGN AND METHODS: We surveyed a random sample drawn from a birth cohort of 557 2-year-old children living in the inner-city of Baltimore. Complete information on all their preventive health care visits and immunization status was obtained from medical record audits of their health care providers. MAIN OUTCOME MEASURES: Age-appropriate immunizations and preventive health care visits. RESULTS: By 3 months of age, nearly 80% made an age-appropriate preventive health visit, but by 7 months of age, less than 40% had a preventive visit that was age-appropriate. In the second year of life, 75% made a preventive health visit between their 12- and 17-month birthdays. The corresponding age-appropriate immunization levels were 71% for DTP1, 39% for DTP3, and 53% for measles-mumps-rubella vaccine. Infants who received their DTP1 on-time were twice as likely to be up-to-date by 24 months of age. CONCLUSIONS: Our analyses focus attention on the performance of the primary health care system, especially during the first 6 months of life. Many young infants are underimmunized despite having age-appropriate preventive visits, health insurance coverage through Medicaid, and providers who receive free vaccine from public agencies. Measles vaccination coverage could be improved by initiating measles-mumps-rubella vaccine vaccination, routinely, at 12 months among high risk populations.

Baltimore↗