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Biomedical subjects

M Burns

Publications and source records attributed to M Burns.

At least 19 recordsLinked to original sources
PubMed1999

Police officers' detection of breath odors from alcohol ingestion.

Police officers frequently use the presence or absence of an alcohol breath odor for decisions on proceeding further into sobriety testing. Epidemiological studies report many false negative errors. The current study employed 20 experienced officers as observers to detect an alcohol odor from 14 subjects who were at blood alcohol concentrations (BACs) ranging from zero to 0.130 g/dl. Over a 4 h period, each officer had 24 opportunities to place his nose at the terminal end of a 6 in. tube through which subjects blew. Subjects were hidden behind screens with a slit for the tube to prevent any but odor cues. Under these optimum conditions, odor was detected only two-thirds of the time for BACs below 0.08 and 85% of the time for BACs at or above 0.08%. After food consumption, correct detections declined further. Officers were unable to recognize whether the alcohol beverage was beer, wine, bourbon or vodka. Odor strength estimates were unrelated to BAC levels. Estimates of BAC level failed to rise above random guesses. These results demonstrate that even under optimum laboratory conditions, breath odor detection is unreliable, which may account for the low detection rate found in roadside realistic conditions.

Adult↗
PubMed1998

Early assessment and in-hospital management of patients with acute myocardial infarction at increased risk for adverse outcomes: a nationwide perspective of current clinical practice. The National Registry of Myocardial Infarction (NRMI-2) Participants.

BACKGROUND: Therapeutic decision making in critically ill patients requires both prompt and comprehensive analysis of available information. Data derived from randomized clinical trials provide a powerful tool for risk assessment in the setting of acute myocardial infarction (MI); however, timely and appropriate use of existing therapies and resources are the key determinants of outcome among high-risk patients. METHODS: Demographic, procedural, and outcome data from patients with MI were collected at 1073 U.S. hospitals collaborating in the National Registry of MI (NRMI 2). Patients were classified on hospital arrival as either "low risk" or "high risk" according to a modified Thrombolysis in Myocardial Infarction II Risk Scale based on predetermined demographic, electrocardiographic, and clinical features. RESULTS: Among the 170,143 patients enrolled, 115,222 (67.5%) were classified as low risk and 55,521 (32.5%) as high risk for in-hospital death, recurrent ischemia, recurrent MI, congestive heart failure, and stroke. Using a composite unsatisfactory outcome measure, in-hospital adverse events were had by a greater proportion of patients initially classified as high risk compared with those classified as low risk. By multivariate analysis, age >70 years, prior MI, Killip class >1, anterior site of infarction, and the combination of hypotension and tachycardia were independent predictions of poor outcome in patients with or without ST-segment elevation on the presenting electrocardiogram. High-risk patients with ST-segment elevation were treated with thrombolytics (47.5%) or alternative forms of reperfusion therapy (9.3%) within 62 minutes and 226 minutes of hospital arrival, respectively. High-risk patients offered reperfusion therapy were also more likely to receive aspirin, beta-blockers (intravenous, oral) and angiotensin-converting enzyme inhibitors within 24 hours of infarction (all p < 0.0001), survive their event (8.4% versus 21.4% p < 0.0001), and leave the hospital sooner than those not reperfused. CONCLUSIONS: This large registry experience included more than 150,000 nonselected patients with MI and suggests that high-risk patients can be identified on initial hospital presentation. The current use of reperfusion and adjunctive therapies among high-risk patients is suboptimal and may directly influence outcome. Randomized trials designed to test the impact of specific management strategies on outcome according to initial risk classification are warranted.

Angioplasty, Balloon, Coronary↗
PubMed1998

Intraretinal oxygen distribution in urethan-induced retinopathy in rats.

This study was performed to explore the interaction between chronic neural degeneration and the subsequent vascular remodeling. Weekly urethan administration in rats from birth produces a retinopathy model characterized by photoreceptor degeneration, retinal vascular regression, and retinal pigment epithelium (RPE) neovascularization. We investigated the hypothesis that altered oxygen distribution across the retina and choroid could be involved in the vascular changes seen in this retinopathy. We compared measurements of vitreal, intraretinal, and choroidal oxygen tension (PO2) distribution in anesthetized and ventilated control and urethan-treated rats at 8 and 16 wk of age with the use of oxygen-sensitive microelectrodes. Striking differences were observed in both choroidal and intraretinal PO2 distribution in urethan-treated rats compared with controls. At both ages, intrachoroidal PO2 was much lower in the urethan-treated rats. In addition, the intraretinal PO2 distribution across the inner retinal layers was more uniform than normal. A small elevation in PO2 was present at 8 wk in the inner nuclear layer where subsequent vascular regression occurred, and a small reduction in PO2 was present at the RPE, which recovered to normal values by 16 wk in regions where RPE vessel networks were first evident. Although the retinal arteries were considerably thinner at both ages in the urethan-treated rats, the vitreal PO2 profiles and superficial retinal PO2 remained normal. The unexpected and large reduction in the oxygen delivery from the choroid found in the urethan-treated rats may account for the lack of major hyperoxia within the pathological retina and the lower oxygen tension in the RPE before the vascular proliferation in this region. We propose that tissue PO2 is an important determinant of the vascular remodeling, which is seen in this model of neural degeneration and that the PO2 distribution changes described in this study help provide a new view of the pathogenesis of this model.

Animals↗
PubMed1996

Sign tracking versus goal tracking in the sexual conditioning of male Japanese quail (Coturnix japonica).

Pairings of a conditioned (CS) and unconditioned (US) stimulus can result in approach to either the CS (sign tracking) or the US (goal tracking). Increasing the spatial or temporal separation between the CS and a US food has been reported to results in a decline in sign tracking and an increase in goal tracking. In the present experiments, sign tracking was the predominant response of male quail (Coturnix japonica) to a CS that was presented up to 91 cm from the door through which a female was presented as the US (Experiment 1). Contrary to reported results with food reinforcement, goal tracking was not facilitated by increasing the spatial separation between the CS and US (Experiment 2) or by introducing a trace interval between them (Experiment 3). The preponderance of sign tracking may reflect an adaptive specialization of sexual conditioning or may be related to the absence of magazine training and the use of a moving US in the sexual conditioning procedures.

Animals↗
PubMed1996

Outcomes research: contemporary issues and historical significance for nurse practitioners.

Outcomes research is not new to the discipline of nursing. However, the driving forces of today's health care environment are resulting in increased emphasis on the study of outcomes. This article presents an overview of the scope of outcomes research, including a historical perspective and contemporary issues. Outcomes research provides an opportunity to demonstrate the effectiveness of nurse practitioner practice.

Humans↗
PubMed1995

Medical and health care needs of families providing in-home care for relatives with developmental disabilities.

The purpose of this investigation was to attempt to describe the health care needs of families providing in-home care to members with developmental disabilities as well as the characteristics and demographics of families providing in-home care. The survey included 761 families who participated in a federal demonstration project in rural southern Georgia. The results indicated that impoverished families need increased assistance to provide adequate medical and health care when providing in-home care to relatives experiencing developmental disabilities. Implications for administration of programs and development of policies are discussed.

Caregivers↗
PubMed1994

A laboratory study of patients with chronic allergic rhinitis: antihistamine effects on skilled performance.

Twenty-four patients with chronic allergic rhinitis participated in a study of antihistamine effects on skilled performance. They were tested while experiencing symptoms and when they were free of symptoms. Within each symptom condition, they attended two sessions; each patient received a placebo capsule at one session and a 50 mg diphenhydramine capsule at the other. Subjects performed a battery of skilled performance tests, which included the Divided-Attention, Visual Backward Masking, Stimulus Response Conflict, and Vigilance tests. They rated the treatments and their performance. Affective states were assessed with the Profile of Mood States. Symptoms did not affect performance. Diphenhydramine impaired vigilance performance and measures of Divided Attention and Stimulus Response Conflict. Visual Backward Masking performance was not affected. The largest performance changes occurred when diphenhydramine was administered to subjects when they were free of symptoms.

Adult↗
PubMed1993

Glomerular C3c localization indicates ongoing immune deposit formation and complement activation in experimental glomerulonephritis.

In antibody-mediated glomerular disease, deposits of C3 (C3b) are common and are degraded by factor I to C3c and C3d. However, the kinetics of C3b degradation in glomerulonephritis have not been defined. To do this, we studied three models of complement-dependent glomerulonephritis with established C3 deposits (passive Heymann nephritis, cationized immunoglobulin G membranous nephropathy, and concanavalin A-anticoncanavalin A glomerulonephritis). C3b deposition was halted by administration of cobra venom factor, and the disappearance of C3c and C3d from glomeruli was measured with specific antibodies and quantitative fluorescence densitometry. Results showed that C3c deposits were reduced by over 85% within 24 hours in all three models. C3c clearance was unaffected by site or mechanism of deposit formation. C3d deposits persisted despite lack of ongoing complement activation. In passive Heymann nephritis when disease activity was monitored by urinary C5b-9 excretion, C3c was cleared in parallel with return of urine C5b-9 excretion to normal values. We conclude that glomerular deposits of C3c are cleared within 24 hours of cessation of complement activation. Positive staining for C3 utilizing antibody specific for the C3c portion documents recent complement activation usually reflecting new immune deposit formation.

Animals↗
PubMed1990

Plasma GABA-like activity in response to ethanol challenge in men at high risk for alcoholism.

Sons of alcoholic fathers (high risk, HR) and matched control men from families without alcoholism (low risk, LR) were administered, in a randomized double-blind fashion, either a placebo beverage or an isovolemic beverage containing ethanol (0.8 g/kg). Serial blood sampling for determination of plasma gamma-aminobutyric acid (GABA)-like activity, mood, and intoxication ratings were performed. The HR subjects were found to have significantly less plasma GABA-like activity than LR during the placebo condition. The alcoholic beverage condition washed out the differences in plasma GABA between groups. Significant interactions between risk group status and beverage conditions were found with respect to plasma GABA-like activity. Alcohol produced an increase in mean GABA-like activities among HR subjects, whereas a slight decline was noted among LR subjects. Plasma GABA-like activity also had a significant inverse correlation with self-reports of perceived tension in the placebo condition, and tension, confusion, and intoxication in response to the alcoholic drink. Since previous investigators have reported reduced plasma GABA levels in alcoholic individuals, reduced plasma GABA-like activity may be a biological marker for vulnerability to alcoholism or for heightened tension as a behavioral factor that predisposes to alcoholism.

Adult↗
PubMed1990

Comprehensive management of renal failure in infants.

From 1986 through 1989, 23 infants (18 of whom were less than 30 days old) required peritoneal dialysis within their first 6 months of life. Modifications to conventional peritoneal dialysis included modified Silastic Tenckhoff catheters, peel-away sheaths for percutaneous insertion, automated peritoneal dialysis "cyclers," and generous omentectomy. With these modifications, there were no bowel perforations, and the infants were successfully dialyzed for prolonged periods. Eight of the 23 infants developed end-stage renal failure and were prepared for transplantation. All had gastrostomy tubes placed to supplement oral nutrition. Living, related transplantation was performed when the child weighted 10 kg. Four of the eight completed this protocol. One child with congenital nephrotic syndrome died before transplantation. One transplant was complicated by a technical problem (venous thrombosis), which resulted in allograft loss and return to peritoneal dialysis. Kidney function, growth, and development in the survivors were excellent.

Catheters, Indwelling↗
PubMed1990

Phospholipid hydrolysis and loss of membrane integrity following treatment of rat brain synaptosomes with beta-bungarotoxin, notexin, and Naja naja atra and Naja nigricollis phospholipase A2.

The effects of the phospholipase A2 (PLA2) toxins, beta-bungarotoxin and notexin, and the PLA2 enzymes from Naja naja atra and Naja nigricollis snake venoms on the plasma membrane integrity of synaptosomes were examined. Synaptosomes were isolated from rat brain cerebral cortex, corpus striatum and hippocampus. Osmotic activity, lactate dehydrogenase leakage, and leakage of 2-deoxy-D-(1-3H)-glucose-6-phosphate were monitored (37 degrees C, 10-120 min) following incubation with 0.5, 5 and 50 nM concentrations of toxins and enzymes. Damage to the synaptosomal plasma membrane was time and concentration but not tissue dependent. The potencies of the treatments were as follows: N. n. atra PLA2 greater than or equal to N. nigricollis PLA2 greater than notexin greater than beta-bungarotoxin. Chelation of Ca2+ with 5 mM EDTA completely inhibited plasma membrane disruption caused by beta-bungarotoxin and N. n. atra PLA2. One mg/ml of bovine serum albumin also blocked the disruptive action of N. n. atra PLA2, while 8 mg/ml was required to antagonize beta-bungarotoxin. A correlation between phospholipid hydrolysis and loss of membrane integrity was also observed. The generation of phospholipid hydrolytic products may be critical in the permeabilization of synaptic plasma membranes by these toxins and enzymes, however, they do not explain the presynaptic specificity and potency of beta-bungarotoxin and notexin.

Animals↗
PubMed1990

Laboratory study of drug-related performance changes.

Performance decrements associated with therapeutic drugs may increase the risk of many common activities that require intact skills. However, accident data that define such risks are difficult to obtain, and the assessment of skill decrements often must be based on data obtained from the laboratory study of drug effects. The validity and reliability of conclusions drawn from laboratory data are a function of experiment design and measurement methods. Critical issues include the assumptions, rationale, and hypotheses underlying laboratory measurement of skills performance. Drug doses and dosing regimens, subject characteristics, and response measures are key variables that limit data interpretation. The design of reported experiments, including the selection of a battery of laboratory tests, reveals the underlying issues, and data from the experiments demonstrate both valid conclusions and constraints on interpretation.

Cardiovascular System↗
PubMed1989

Outpatient pulmonary rehabilitation. A new lease on life.

For patients with restrictive as well as obstructive disease, pulmonary rehabilitation offers a comprehensive program that affects all areas of their life. Marked improvement is seen in exercise tolerance and in performing all activities of daily living. Compliance with drug therapy and other prescribed treatment also improves. The isolation, depression, and irritability that so often accompany respiratory disease are alleviated by ongoing membership in patient support groups. Patients again become active participants in life.

Ambulatory Care↗
PubMed1989

A new pendant oxygen-conserving cannula which allows pursed lips breathing.

Multiple benefits of oxygen therapy for hypoxemic patients with chronic lung disease are well established. Steady flow oxygen therapy is inefficient, wasteful and has a high cost. The Oxymizer pendant improves efficiency of oxygen delivery compared with SF. However, the device requires that the patient inhale and exhale nasally to maximize its oxygen-saving properties. When patients do PLB they may not receive full oxygen-saving benefit of the pendant. Yet PLB itself can increase SaO2. We evaluated an AP, which does not require nasal exhalation, in nine patients with COPD. We measured SaO2 while breathing oxygen via SF and the AP with nasal-only breathing and PLB. Results indicate that the AP maintains an increase in SaO2 over SF during nasal-only breathing and a further increase during PLB. We conclude that AP acts as an oxygen conserver during PLB; PLB with the AP achieves greater savings than with nasal-only breathing.

Aged↗
PubMed1988

Effects of terfenadine, diphenhydramine, and placebo on skills performance.

The behavioral effects of the antihistamines terfenadine and diphenhydramine were compared in a placebo-controlled, double-blind crossover study. Performance of skills deemed important in safe man-machine interactions was objectively assessed one, three, and five hours after administration of test substances. The results indicate that diphenhydramine use resulted in various degrees of impairment of the ability to perform a visual-search task, a tracking task, a divided-attention task, and a vigilance task. Terfenadine users performed as well as or better than placebo-treated subjects. No differences between terfenadine and placebo were found on a subjective evaluation scale. Diphenhydramine users consistently reported feelings of impairment.

Adult↗