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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 217 records · Page 12Linked to original sources
PubMed1999

Relationship of physical exercise and ageing to growth hormone production.

OBJECTIVE: The normal decline in physiological function with ageing is associated with a decrease in bioavailable growth hormone. Growth hormone has been shown to alter body composition and increase fat-free mass in older men. Increased physical fitness is accompanied by an increase in 24-h growth hormone release. The purpose of this study was to examine the effect of exercise on declining growth hormone concentrations with increasing age. DESIGN AND PATIENTS: The growth hormone production of 10 male subjects running over 40 miles per week was compared to 10 healthy age-matched sedentary males (controls 57.7 +/- 2.8 vs. runners 60.5 +/- 3.4 years). All subjects underwent a basal assessment including a two-hour serum growth hormone profile followed by estimation of maximal exercise capacity on a cycle ergometer with growth hormone estimations at peak exercise activity and every five minutes whilst cycling at 40% of maximal exercise capacity. RESULTS: Maximal exercise capacity confirmed the lifestyles of the two groups (VO2 max controls 22.36 +/-6.05 vs. runners 34.91 +/- 13.13 l/min/kg, P = 0.01). The runners had lower body-mass indices than controls (BMI 22. 3 +/- 1.5 vs. 25.5 +/- 2.0 kg/m2, P = 0.002). Peak growth hormone level during a two-hour resting profile was higher in the runners (median (range) controls 2.10 (0.20-12.20) vs. runners 5.25 (0.80-21. 00) mU/l, P = 0.03) as was the average growth hormone level during the two hour profile (mean growth hormone per 2 h median (range): controls 0.54 (0.03-4.88) vs. runners 2.17 (0.25-7.45) mU/l, P = 0. 04). Growth hormone production at maximal exercise capacity was similar. Sex hormone binding globulin and testosterone were significantly higher in the runners. CONCLUSIONS: The results suggest that regular intensive exercise in older male subjects is associated with higher growth hormone and testosterone levels and that exercise may have a role in counteracting the normal decline in growth hormone with ageing.

Aging↗
PubMed1999

Initiating research with doubly vulnerable populations.

Some research questions can only be answered by members of a vulnerable group. Frequently members of these groups are doubly vulnerable as they experience more than one factor that diminishes their autonomy. Initiating research with doubly vulnerable persons presents unique and often difficult challenges. Because of these challenges, many researchers purposefully exclude doubly vulnerable groups from research endeavours. Thus, the health care needs and concerns of individuals considered doubly vulnerable are often not addressed in the scientific literature. This article presents two challenges frequently encountered when initiating research with doubly vulnerable populations: resolving pre-investigation issues and gaining access to vulnerable populations. Ethically sound strategies for confronting these challenges are discussed. Researchers' experiences with doubly vulnerable populations are also incorporated. Only when doubly vulnerable groups receive the appropriate research attention are the standards of their care and their quality of life enhanced.

Ethics, Nursing↗
PubMed1999

Guns at college.

A random sample of more than 15,000 undergraduate students from 130 4-year colleges answered a mailed questionnaire concerning firearm possession. Approximately 3.5% of the sampled students reported they had a working firearm at college. Students with guns were more likely to be male, White, or Native American; to binge drink and need to start the day with alcohol; to be members of a fraternity or sorority; to live off campus; and to live with a spouse or significant other. Having a gun was positively associated with driving after binge drinking, being arrested for driving under the influence of alcohol, and damaging property as a result of alcohol ingestion. Students with guns were also more likely to be injured severely enough to require medical attention, especially for injuries occurring in fights or car crashes. Overall, students with guns at college were more likely than others to engage in activities that put themselves and others at risk for injury.

Accidents, Traffic↗
PubMed1999

A model to explain the relationship between sexual abuse and HIV risk among women.

This paper presents a model developed to advance the understanding of the relationship between sexual abuse and HIV risk among women. It is proposed that the relationship is mediated by many of the long-term sequelae of sexual abuse. The process of mediation is believed to occur through various causal pathways propelled by specific underlying mechanisms that increase the likelihood of HIV risk. The following causal pathways are proposed: (1) initiation of and/or increasing reliance on drug use as a method of coping with the sexual abuse experience, (2) problems with sexual adjustment related to sex risk taking, and (3) psychopathology (e.g. depression) which increases the likelihood of an individual participating in HIV risk behaviours. These hypothesized pathways are based on the characteristics and behaviours of individuals with histories of sexual abuse and do not take into account the influence of the individual's social environment. Increasingly, evidence suggests that understanding the social context of HIV risk is crucial to the development of preventive interventions. Therefore, a final pathway is explored which suggests that specific social network characteristics (e.g. network membership type, social support, and social isolation) influence HIV risk exposure opportunities among women with sexual abuse histories.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Heparin and enoxaparin enhance endotoxin-induced tumor necrosis factor-alpha production in human monocytes.

OBJECTIVE: To determine whether heparin or the low-molecular-weight heparin enoxaparin alter lipopolysaccharide (LPS)-induced monocyte activation. SUMMARY BACKGROUND DATA: Heparin is widely used in clinical practice to inhibit the coagulation cascade. However, heparin also is a naturally occurring glucosaminoglycan and a pleiotropic immunomodulator that binds to a variety of proteins. LPS is a component of gram-negative bacteria and is thought to be responsible for many of the deleterious effects seen in sepsis. The binding of LPS to CD14 induces a signaling cascade that results in the release of many inflammatory mediators, including tumor necrosis factor-alpha (TNF-alpha). METHODS: Monocytes from healthy volunteers were isolated and cultured in the presence of saline, LPS (10 ng/ml), heparin (0.1 to 1000 microg/ml), or enoxaparin (0.1 to 1000 microg/ml). In blocking experiments, cells were pretreated for 60 minutes with the monoclonal anti-CD14 antibody MY4 (10 microg/ml) or with isotype-matched control IgG2 (10 microg/ml). TNF-alpha values were measured with enzyme-linked immunosorbent assay. Significance was assessed with analysis of variance. RESULTS: Heparin (10 to 1000 microg/ml) and enoxaparin (1000 microg/ml) significantly enhanced LPS-induced TNF-alpha release. Heparin (1000 microg/ml) or enoxaparin (1000 microg/ml) did not produce TNF-alpha in the absence of LPS. Blockade of CD14 abrogated both LPS-induced TNF-alpha release and the effect of heparin or enoxaparin to enhance LPS-induced TNF-alpha release. CONCLUSIONS: The effect of heparin to enhance LPS-induced TNF-alpha release is a biologic phenomenon that reveals a novel and potentially important host defense mechanism during endotoxemia and sepsis. Binding of LPS to CD14 is necessary to induce this phenomenon, suggesting that both heparin and enoxaparin induce signaling mechanisms that are downstream from the initial binding of LPS on CD14.

Anticoagulants↗
PubMed1999

Measuring quality in hospitals: is there a difference between for-profits and not-for-profits?

Health care professionals agree that by measuring quality, improvements can be made in care delivery. There are measurable differences between not-for-profit and for-profit hospitals, both in public perception and care outcomes. The ability by consumers, insurers and providers to easily access quality data will drive the health care industry to take a quality focus in their daily business. Quality providers with measurable results will gain a larger share of health care dollars and consumer trust. Physicians will choose to partner with the quality leaders and will refine their practices as part of the quality evolution.

Diagnosis-Related Groups↗
PubMed1999

Atrial natriuretic peptide levels in geriatric patients with nocturia and nursing home residents with nighttime incontinence.

OBJECTIVES: To determine if nocturnal polyuria in geriatric patients with nocturia and nocturnal incontinence is associated with elevated plasma atrial natriuretic peptide (ANP) levels. DESIGN: Case series. SETTING: Four nursing homes and two board and care facilities. PARTICIPANTS: Fifty-four nursing home residents and 26 board and care residents with a mean age of 86. MEASUREMENTS: Daytime (7:00 a.m. to 7:00 p.m.) and nighttime (7:00 p.m. to 7:00 a.m.) urine volumes of incontinent nursing home residents were measured over 3 days and 3 nights by reweighing preweighed adults diapers and toileting inserts emptied by research staff for the board and care group. Blood was drawn in the early morning (5:00 a.m. to 7:00 a.m.) before subjects arose and in the evening after an hour of lying in bed (8:00 p.m. to 11:00 p.m.), and plasma ANP levels were determined by radioimmunoassay. RESULTS: Forty-nine (61%) of the subjects had nocturnal polyuria as defined by night/total urine volume ratios > or = 50%. There was no significant difference between those with night/total ratios > or = 50% versus < 50% in plasma levels of ANP in the early morning (44.2+/-33.3, median 35.7 pg/mL vs 40.9+/-39.2, median 28.5; P = .36 by Mann Whitney U) or in the evening (43.4+/-28.8, median 36.4 pg/mL vs 49.6+/-53.1, median 34.4; P = .58). Nor was there any significant correlation between night/total urine volume ratio and morning or evening ANP levels (r = .01, P = .96 and r = .23, P = .31, respectively). CONCLUSIONS: In this sample of geriatric patients with nocturia and nursing home residents with nighttime urinary incontinence, ANP levels were elevated, but increased nighttime urine production was not associated with higher levels. Because of the variability in ANP levels, our power to detect such an association was low, and we cannot draw any definitive conclusions. Although high plasma ANP levels are unlikely to be a primary cause of nocturia and nighttime incontinence, they may, when combined with other factors such as low antidiuretic hormone levels, sleep disorders, and low functional bladder capacity, contribute to these symptoms in some geriatric patients.

Aged↗
PubMed1999

Clinical, haematological and biochemical findings in foals with neonatal Equine herpesvirus-1 infection compared with septic and premature foals.

A retrospective multicentre study comparing historical, clinical, haematological, acid-base and biochemical findings of foals with Equine herpesvirus-1 (EHV-1) infection, septicaemia or prematurity was performed to determine if early diagnosis of EHV-1 foals was possible. Fifty-three foals were studied and were assigned to one of 2 groups: herpes positive (n = 14) or herpes negative (n = 39). The latter group included 20 septic, 11 premature, and 8 premature and septic foals. The presence of herpes antigen was confirmed by immunoperoxidase histochemical staining of tissues from necropsied foals. A nonparametric statistical analysis followed by a backwards elimination logistic regression was performed to establish a model at a P value of <0.05. All herpes positive foals died, while 47% (9/19) of the septic foals survived. Based upon our analysis, herpes positive foals were more likely to have total white blood cell counts less than 3 x 10(9)/l and to be icteric as compared to the septic and premature foals. Despite profound hepatic necrosis in the herpes positive foals, liver enzymes were not elevated and were not significantly different from the controls.

Acid-Base Equilibrium↗
PubMed1999

Immune responses in farm workers after exposure to Bacillus thuringiensis pesticides.

Although health risks to pesticides containing Bacillus thuringiensis (Bt) have been minimal, the potential allergenicity of these organisms has not been evaluated. Therefore, a health survey was conducted in farm workers before and after exposure to Bt pesticides. Farm workers who picked vegetables that required Bt pesticide spraying were evaluated before the initial spraying operation (n = 48) and 1 and 4 months after (n = 32 and 20, respectively). Two groups of low- (n = 44) and medium- (n = 34) exposure workers not directly exposed to Bt spraying were also assessed. The investigation included questionnaires, nasal/mouth lavages, ventilatory function assessment, and skin tests to indigenous aeroallergens and to a variety of Bt spore and vegetative preparations. To authenticate exposure to the organism present in the commercial preparation, isolates from lavage specimens were tested for Bt genes by DNA-DNA hybridization. Humoral immunoglobulin G (IgG) and immunoglobulin E (IgE) antibody responses to spore and vegetative Bt extracts were assayed. There was no evidence of occupationally related respiratory symptoms. Positive skin-prick tests to several spore extracts were seen chiefly in exposed workers. In particular, there was a significant (p < 0.05) increase in the number of positive skin tests to spore extracts 1 and 4 months after exposure to Bt spray. The number of positive skin test responses was also significantly higher in high (p < 0.05) than in low- or medium-exposure workers. The majority of nasal lavage cultures from exposed workers was positive for the commercial Bt organism, as demonstrated by specific molecular genetic probes. Specific IgE antibodies were present in more high-exposure workers (p < 0.05) than in the low and medium groups. Specific IgG antibodies occurred more in the high (p < 0.05) than in the low-exposure group. Specific IgG and IgE antibodies to vegetative organisms were present in all groups of workers. Exposure to Bt sprays may lead to allergic skin sensitization and induction of IgE and IgG antibodies, or both.

Antibodies, Bacterial↗
PubMed1999

Comparison of in vitro tests for evaluation of passive transfer of immunoglobulins in giraffe (Giraffa camelopardalis).

Serum samples from captive giraffe (Giraffa camelopardalis) were tested to assess passive transfer of immunoglobulins using in vitro methods developed for domestic ruminants. Estimated immunoglobulin levels were compared using five tests (protein electrophoresis, total protein refractometry, zinc sulfate turbidity, glutaraldehyde coagulation, and sodium sulfite turbidity). A linear relationship was observed among total protein, gamma globulin (electrophoretic measurement), and immunoglobulin level based on spectrophotometric measurement of zinc sulfate turbidity. Nonquantitative assays also demonstrated statistical correlation with the quantitative methods. Using criteria similar to those established for domestic species, cutoff values for failure of passive transfer (FPT) were established for these tests in neonatal giraffe: 1) total protein <6.0 g/dl; 2) gamma globulin < 0.5 g/dl; 3) estimated immunoglobulin level < 1,000 mg/dl (zinc sulfate turbidity); 4) glutaraldehyde coagulation test negative; or 5) no visually detectable turbidity in 16% sodium sulfite or Bova-S negative. Retrospective examination of the medical histories showed a strong statistical association between animals designated as having FPT and those that were removed from their dams based on clinical assessment to be hand-reared. Application of these tests in the field should allow earlier detection and intervention for FPT in neonatal giraffe.

Animals↗
PubMed1999

Right bundle branch block as a cause of false-negative ECG classification of inferior myocardial infarction.

It is generally accepted in clinical electrocardiography that a right bundle branch block (RBBB) does not interfere with the electrocardiographic (ECG) diagnosis of myocardial infarction (MI). The basic assumption is that the initial excitation wavefronts are relatively unchanged in RBBB. This study compared serial changes in Q wave duration in inferior leads II, III, and aVF in 9 patients who developed RBBB within 3 weeks after myocardial revascularization procedure (RBBB group) and in 41 revascularized patients without RBBB in the same observation period (control group). Q wave durations in the electrocardiograms obtained before the patients' procedures were not significantly different between the study and control groups. However, Q wave durations shortened significantly more in the RBBB group than in the control group. The most pronounced Q wave duration shortening took place in lead aVF, -18.2 ms in the RBBB group versus -3.8 ms in the control group (P = .0001). The shortening was less pronounced, although significant, in leads II and III: II, -7.6 +/- -10.9 ms in the RBBB group vs -2.3 +/- -3.5 ms in the control group (P = .01); III, -11.3 +/- -10.5 ms vs -2.6 +/- -6.5 ms (P = .002); aVF, -18.2 +/- -13.5 ms vs -3.8 +/- -5.3 ms (P < .0001). It is concluded that incident RBBB complicating revascularization procedures may cause significant alterations in spatial orientation of the initial excitation wavefronts. This may be a potential source of false-negative ECG diagnosis of inferior MI, particularly in clinical trials where serial ECG analysis is an important part in MI classification.

Bundle-Branch Block↗
PubMed1999

Moving substance-abusing women from welfare to work.

Substance abuse and welfare reform are among the nation's highest priorities, and research that examines linkages between the two is of extreme importance to both government policy and the community. Welfare reform will have serious implications for substance abusers as well as for the various professionals who treat them and work to move their clients into functional recovery and self-sufficiency. Within the context of welfare reform and the special needs of substance-abusing populations, the present study examines current welfare status, work status, and barriers and facilitators to gaining and maintaining employment among 100 low income women who participated in a long-term residential substance-abuse treatment program in Miami, Florida. Participants completed a face-to-face interview to assess a detailed employment history and current sources of income as well as the Addiction Severity Index. Results indicate that completers of the treatment program were more likely to be working post-discharge than non-completers. Similarly, the longer the length of stay in the program, the more likely the client was to be working post-discharge. Multivariate analysis indicates a high-school education, participation in the treatment center's aftercare program, and treatment duration of more than one year were independently related to work status. These data suggest that as welfare reform becomes a reality, continuing support of various types, particularly drug treatment, is needed to assist substance-abusing women in gaining and maintaining employment.

Demography↗
PubMed1999

Treatment of 70(+)-year-olds with recurrent major depression. Excellent short-term but brittle long-term response.

The authors compared response rates, by age (60-69 vs. 70+), to acute, continuation, and 1-year maintenance depression treatment. Patients (N = 180) received open combined treatment with nortriptyline (NT)/placebo and interpersonal psychotherapy (IPT). Patients who recovered then entered randomized, double-blind maintenance treatment with NT or placebo or received maintenance monthly IPT (combined with NT or placebo). Comparison of time-to-remission and recovery and absolute rates of remission, relapse, recovery, and recurrence yielded similar times to/rates of remission and recovery; however, older patients had far more recurrence during the first year of maintenance therapy. Although responses to acute and continuation treatment with combined NT and psychotherapy were similar, the older group had more recurrence in the first year of maintenance. Continuation of combined medication and psychotherapy may represent the best long-term treatment.

Age Factors↗