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Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 307 records · Page 17Linked to original sources
PubMed1997

Promoting HIV prevention: a problem identification approach to interventions in post-HIV test counselling.

HIV antibody testing now occurs in a wide variety of clinical settings. Counselling at the time of HIV testing involves more than obtaining informed consent and there can be an active role for HIV prevention strategies. Whilst research has not clearly identified the effectiveness of either HIV testing or counselling for HIV prevention, HIV testing does allow for focused discussions with individuals about risk behaviour. Therefore all efforts to refine interventions to enhance HIV prevention must be encouraged. Interventions which encourage clients to examine beliefs about behaviours and relationships can bring about an increase in perceived choices, and thereby lead to changes in behaviour. A model is presented for conducting post-HIV test counselling for use by health professionals involved in HIV testing. Examples of questions and question styles are provided to illustrate this framework which addresses prevailing beliefs and encourages contributions from clients.

AIDS Serodiagnosis↗
PubMed1997

Does dextrose affect analgesia or the side effects of intrathecal sufentanil?

UNLABELLED: Intrathecal (i.t.) sufentanil provides rapid effective pain relief for early labor, but it also produces undesirable side effects, which may be primarily related to cephalad spread. Although the combination of dextrose and positioning the patient head-up limits the spread of other spinally administered drugs, these factors have not been examined in laboring women receiving i.t. sufentanil. We hypothesized that the addition of dextrose to i.t. sufentanil injected with women in the sitting position would limit cephalad spread and side effects. Sixty-six healthy nulliparous parturients in early labor were randomized to receive 2-mL i.t. injections of sufentanil 10 micrograms plus saline with patients in either the lateral decubitus or sitting position, sufentanil 10 micrograms plus dextrose 7.5% with patients in either the lateral decubitus or sitting positions, or plain dextrose 7.5%. Pain scores using a 10-cm visual analog pain scale, sensory block height, and side effects were recorded. Dextrose 7.5% did not affect cephalad spread, as measured by block height to pin testing, but it did significantly reduce the duration of analgesia and the incidence of pruritus from i.t. sufentanil administered to patients in the sitting position compared with patients in the lateral position. In contrast, patient position had no effect on analgesia or side effects in patients receiving i.t. sufentanil in saline. I.t. dextrose alone had no effect. IMPLICATIONS: The authors conclude that the addition of dextrose to intrathecal sufentanil injected into patients in the sitting position reduces the duration of analgesia without significantly reducing side effects with the exception of pruritus, and therefore does not improve the clinical utility of intrathecal sufentanil.

Adult↗
PubMed1997

Suitability and durability of multiple internal thoracic artery coronary artery bypasses.

OBJECTIVE: The authors evaluate operative and extended outcomes of coronary artery bypass surgery using the bilateral internal thoracic arteries (ITAs) as bypass grafts. The authors conclude that the procedure is viable and of long-term benefit to most patients. SUMMARY BACKGROUND DATA: Multiple ITA grafting was met with early enthusiasm by the surgical profession, but skepticism and controversy arose with reports of increased operative morbidity, insufficient graft blood flow, a high incidence of failure of the right ITA, and uncertainty about durability and long-term benefits. METHODS: To assess the actual incidence and impact of these complications and long-term results, the authors prospectively studied 500 consecutive patients with multiple ITA bypasses, constituting the closely observed and carefully documented experience of one surgeon over an 11-year period. RESULTS: Operative mortality in the series of 500 patients was 1.8%, perioperative myocardial infarction (new Q wave) rate was 0.6%, and deep sternal wound infection occurred in 1%. Six patients (1.2%) had strokes, and nine patients (1.8%) were returned to the operating room to control bleeding. One hundred ninety-eight patients who had abnormal stress test results before surgery were retested within 3 months of surgery. Ninety-four percent of these were normal, 3% were nondiagnostic, and 3% were abnormal. After a mean follow-up of 7.1 years (mode, 7.2 years), 87.5% of patients in the sample were alive, and 93.2% of this group have experienced continuing good clinical results (New York Heart Association class I or II). Eighty-nine patients who underwent an angiogram had 90.8% patency rates of ITA bypasses and 84.5% patency of vein grafts. Only two patients required repeat operations. CONCLUSIONS: The operative results did not support the contention that the coronary artery bypass using ITA procedure produces higher than acceptable mortality and morbidity rates. Multiple ITA bypasses can be performed without excessive morbidity, with low reoperation rates and long-term outcomes that should encourage skeptics to reconsider the procedure's clinical value.

Aged↗
PubMed1997

A comparison of the standard approach and the NONMEM approach in the estimation of bioavailability in man.

There has recently been concern about confidence intervals calculated using the standard error of parameter estimates from NONMEM, a computer program that uses a non-linear mixed-effects model to calculate relative bioavailability (F), because of possible downward bias of these estimates. In this study an alternate approach, the log-likelihood procedure, was used to calculate the confidence intervals for F from NONMEM. These were then compared with those calculated using the standard error of the parameter estimates, the traditional NONMEM approach, and the standard model-independent method, to determine whether bias exists. By use of data from a single dose, open cross-over study of ibuprofen using 14 healthy male volunteers, NONMEM was shown to give results consistent with those obtained using the standard model-independent method of analysis and could be a useful tool in the determination of F where conditions for using the standard method of analysis are not optimum. The width of the confidence interval for F using the log-likelihood procedure was narrower and non-symmetrical when compared with that obtained using the traditional NONMEM approach. The width of the confidence interval obtained using the traditional NONMEM method was similar to that from the standard approach, however the parameter estimate for F was higher than that obtained from the standard method. This could have been because of an outlier in the data set to which the standard approach is more sensitive. No downward bias was found in the confidence intervals from NONMEM. The bioavailability data set was of relatively low variability and more research with highly variable data is necessary before it can be concluded that the confidence intervals calculated from NONMEM can be used for hypothesis testing.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Women with HIV disease attending a London clinic.

OBJECTIVE: To examine ethnic, relationship, health, and mental health factors for a cohort of women with HIV infection attending an inner London clinic. DESIGN AND METHODS: Structured schedules were utilised to analyse ethnic group, family, and reproduction issues, mental and physical health for 100 women drawn consecutively from attenders at an inner London HIV clinic RESULTS: 51% of the women were non-ethnic minority groups and 49% were from ethnic groups. HIV testing was often as a result of symptoms or partner illness. One in five had disclosed their status to one person only or no one. Ethnic minority women were more likely to restrict disclosure. Forty seven per cent of the women had 100 children with more children reported in ethnic minority families; 28% of the children had been tested for HIV and five were confirmed HIV positive; 9% of children were born after HIV diagnosis. Nineteen women reported one or more termination of pregnancy, the majority before HIV diagnosis. Three quarters had a partner of whom 56 knew the partner's status. Women with HIV positive partners were more likely to have children. Women kept in ignorance of partner status were more likely to be ethnic minority women. Thirty two per cent had an AIDS diagnosis, diagnosed mostly in the UK. Medical and counselling service uptake was high. Gynaecological problems were common (49% had one or more problem) and 34% had at least one hospital admission. A wide range of counselling issues were recorded, with variations over time. Suicidal issues were relevant for 13% of women (69% ideation, 31% attempts). Significant life events were noted for many women with allied coping demands. CONCLUSIONS: There are a wide range of issues for women with HIV and systematic differences between ethnic and non-ethnic women and those with or without children.

AIDS Serodiagnosis↗
PubMed1997

Glucose production and gluconeogenesis are negatively related to body weight in mechanically ventilated, very low birth weight neonates.

The regulation of gluconeogenesis by low birth weight infants remains poorly delineated. To investigate this, 15 5-d-old infants (26-31-wk gestational age, 795-1485-g body weight), were infused i.v. for 4 h with uniformly labeled [U-13C]glucose (5 mg/kg/min) as the sole source of glucose. Intralipid (3 mg/kg/ min) was provided, but no amino acids were given. Blood samples were taken immediately before and after 4 h of tracer infusion. The isotopic enrichments of plasma glucose and alanine were measured by selected ion monitoring gas chromatography mass spectrometry. Glucose production rates were calculated from the isotopic dilution of plasma [U-13C]glucose and the glucose infusion rate. Gluconeogenesis was estimated from the relative isotopic enrichments of [M + 3]- and [M + 6]-glucose, using the isotopic enrichment of plasma [U-13C]alanine, to define the isotopic dilution of the 3-carbon pool, and previously published equations to calculate the isotopic dilution of hepatic oxaloacetate. Glucose production (15 +/- 9 mumol/kg/min) was negatively related to body weight (r = -0.67; p < 0.05) and the ratio of the isotopic enrichments of [13C3]alanine:[13C6]glucose (0.27 +/- 0.07) was positively related to body weight (r = 0.74; p < 0.025). Both relationships were exponential. Gluconeogenesis (via pyruvate) accounted for 72 +/- 28% of glucose production, and gluconeogenesis per unit body weight was negatively and exponentially (r = -0.82; p < 0.005) related to body weight. These results demonstrate that neonates whose birth weights are less than 1200 g have a particularly high glucose production rate secondary to enhanced gluconeogenesis. We speculate that these results reflect a high weight-specific glucose demand that is met by up-regulation of gluconeogenesis.

Body Weight↗
PubMed1997

Serum sex hormone levels are related to breast cancer risk in postmenopausal women.

We conducted a nested case-control study to prospectively evaluate the relationship of serum estrogens and androgens to risk of breast cancer in postmenopausal women. From 1977 to 1987, 3375 postmenopausal women free of cancer and not taking replacement estrogens donated blood to the Breast Cancer Serum Bank in Columbia, Missouri. Of these, 72 were subsequently diagnosed with breast cancer. For each case, two controls matched on age and date and time of day of blood collection were selected using incidence density matching. The median age of subjects at blood collection was 62 years; the time from blood collection to diagnosis ranged from less than 1 to 9.5 years with a median of 2.9 years. Risk of breast cancer was positively and significantly associated with serum levels of estrogens and androgens. Compared to women in the lowest quartile, those in the highest quartile for non-sex hormone-binding globulin (non-SHBG) bound (bioavailable) estradiol had a relative risk of 5.2 (95% confidence interval [CI] = 1.5-18.5) and those in the highest quartile for testosterone had a relative risk of 6.2 (95% CI = 2.0-19.0). Our results lend considerable support to the hypothesis that serum concentrations of estrogens and androgens are related to the subsequent diagnosis of breast cancer in postmenopausal women.

Aged↗
PubMed1997

Problems associated with drug residues in beef from feeds and therapy.

Drug residues in beef have been reported internationally. These include antimicrobials, anti-inflammatories, growth promotants, parasiticides and insecticides. The main factors associated with residues are animal age and use, and failure to observe withdrawal time for regular or extra-label use. Public health concerns include toxic and anaphylactic reactions, and development of drug-resistant strains of bacteria. The maximum residue level (MRL) is the current standard for residues in food adopted by the Codex Committees of the Food and Agriculture Organisation and World Health Organisation, but is not universally accepted or standardised. Detection of residues at slaughter is a critical point in residue control. Several live animal tests are available, but these vary in reliability and usage. After slaughter, tissues sampled and tests used are more uniform. To prevent international trade barriers associated with drug residues in beef, the following conditions should be implemented: standardisation of testing methods used to detect drug residues; standardisation of methods for determining MRLs; establishment of active surveillance programmes to monitor residues.

Age Factors↗
PubMed1997

Human articular cartilage storage in cell culture medium: guidelines for storage of fresh osteochondral allografts.

The viability of transplanted articular cartilage is one of the determinants of outcome following the transplantation of osteochondral allografts. Disappointing results from cryopreservation have led to the practice of fresh transplantation of articular segments, especially for posttraumatic defects. To date, no studies have demonstrated in vitro viability rates for refrigerated human cartilage awaiting transplantation. This study evaluates the effects of storage on the viability of human chondrocytes using cell culture medium. Human articular cartilage obtained from notchplasties was stored for up to 48 hours in cell culture medium. Radioactive 35S-sulfate uptake was determined at 0, 24, and 48 hours, as a measure of protein, synthesis, and chondrocyte viability. Specimens were stored at 4 degrees C in culture medium. Results showed an average decrease in 35S-sulfate uptake of 0.8% at 24 hours and 6.4% at 48 hours, indicating a high level of chondrocyte viability after refrigeration. Because transplantation typically is performed within 24 hours of tissue harvest, it appears that nearly 100% of chondrocytes should survive fresh transplantation.

Cartilage, Articular↗
PubMed1997

The quality and outcomes management connection.

Measuring outcomes has become an essential part of quality improvement efforts. An outcomes management program can contribute to quality activities through the identification and quantification of outcomes and variances that can serve as performance measures. The COMIT model is highlighted as a process that can be used by multidisciplinary teams to promote outcome improvement. In addition, the Joint Commission on Accreditation of Healthcare Organizations functions and their relationship to an outcomes management effort are presented.

Humans↗
PubMed1997

ICAM-1-mediated adhesion of peripheral blood monocytes to the maternal surface of placental syncytiotrophoblasts: implications for placental villitis.

Accumulation of maternal monocytes in the villous/intervillous space (villitis) is associated with increased risk of perinatal morbidity and mortality and may initiate in utero transmission of cell-associated infectious agents such cytomegalovirus and HIV-1. We have developed an in vitro model of trophoblast syncytialization and have investigated the adhesive interactions between this tissue and peripheral blood monocytes. We show that monocytes strongly adhere to cultured syncytiotrophoblasts (STs) and that treatment with the inflammatory cytokines interferon-gamma, tumor necrosis factor-alpha, and interleukin-1 alpha greatly increase the number bound. Pretreatment of STs with these cytokines upregulated apical expression of intercellular cell adhesion molecule (ICAM)-1 but not E-or L-selection, ICAM-2 or -3, or various integrins. ICAM-1 expression was cytokine concentration dependent, significantly increased within 6 hours of treatment, peaked after 24 hours, and remained undiminished for 48 hours after cytokine removal from the cultures. Adhesion of monocytes to STs was inhibited > 80% by antibody to ICAM-1 or its cognate ligand LFA-1. ICAM-1 was detected immunohistochemically only in rare foci on intact term placental villi. These results suggest that villous trophoblast expression of ICAM-1 occurs only during an immune inflammatory reaction and that aberrant expression of this molecule may be an important pathological feature in those immunoinflammatory disorders of the placenta characterized by an excessive accumulation of leukocytes in the intervillous/villous space such as spontaneous abortion, perinatal hematogenous infections, and villitis of unknown etiology.

Cell Adhesion↗
PubMed1997

Relationship of serum dehydroepiandrosterone (DHEA), DHEA sulfate, and 5-androstene-3 beta, 17 beta-diol to risk of breast cancer in postmenopausal women.

Laboratory evidence suggests a role for dehydroepiandrosterone (DHEA) and its metabolite 5-androstene-3 beta, 17 beta-diol (ADIOL) in mammary tumor growth. Serum DHEA also has been related to breast cancer in postmenopausal women, but the relationship of ADIOL to risk has not been evaluated previously. To assess the relationship of serum DHEA, its sulfate (DHEAS), and ADIOL with breast cancer risk in postmenopausal women, we conducted a prospective nested case-control study using serum from the Columbia, MO Breast Cancer Serum Bank. Cases included 71 healthy postmenopausal volunteers not taking replacement estrogens when they donated blood and who were diagnosed with breast cancer up to 10 years later (median, 2.9 years). Two randomly selected controls, who also were postmenopausal and not taking estrogens, were matched to each case on exact age, date (+/-1 year), and time (+/-2 h) of blood collection. Significant (trend P = 0.02) gradients of increasing risk of breast cancer were observed for increasing concentrations of DHEA and ADIOL, and women whose serum levels of these hormones were in the highest quartiles were at a significantly elevated risk compared to those in the lowest; their risk ratios were 4.0 [95% confidence interval (CI), 1.3-11.8) and 3.0 (95% CI, 1.0-8.6), respectively. The relationship of DHEAS to breast cancer was less consistent, but women whose serum DHEAS concentration was in the highest quartile also exhibited a significantly elevated risk ratio of 2.8 (95% CI, 1.1-7.4). Results of this prospective study support a role for the adrenal androgens, DHEA, DHEAS, and ADIOL, in the etiology of breast cancer.

Aged↗