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Biomedical subjects

M F Mason

Publications and source records attributed to M F Mason.

At least 19 recordsLinked to original sources
PubMed2003

Weighing the care: patients' perceptions of physician care as a function of gender and weight.

OBJECTIVE: To examine patients' reports of the level of care that they receive from their physicians, and determine the influence of weight and gender in these reports. DESIGN: : In a four-cell design, male and female, overweight and nonoverweight patients reported on the medical care that they received immediately following their appointment. SUBJECTS: A total of 125 patients affiliated to one of four large clinics in the Texas Medical Center of Houston completed this study. MEASUREMENTS: Patients reported the positivity of the care that they received, the time that physicians spent with them, and the extent to which physicians discussed weight-related topics with them. RESULTS: Overweight patients, as a whole, did not report poorer levels of care than did their thinner counterparts. Rather, the weight and gender of the patient significantly interacted across each of the measures to reveal some divergence between male and female patients' weight-based experiences. When significant differences in reported perceptions emerged, overweight men reported deficits in care relative to average weight men (eg, physicians spent less time), whereas overweight women reported enhanced care relative to average weight women (eg, better levels of care, more topics discussed). CONCLUSION: Based on patients' reports, this study reveals that physician care may not be as influenced by patient weight as previously thought. Yet, there is a discernable impact of patients' weight on physician behavior. Overweight men, who may comprise the most at-risk population, indicate that less time is spent with them than that indicated by average weight men. While this may be alarming, overweight women do not report reductions in care. We propose that not only might physicians respond to them differently, but overweight female patients may also be engaging in denial strategies or compensatory behaviors that assure them of quality care.

Adult↗
PubMed1996

The cost-effectiveness of terazosin and placebo in the treatment of moderate to severe benign prostatic hyperplasia.

OBJECTIVES: To evaluate the cost-effectiveness and functional status effects of terazosin, an alpha(1)-adrenoceptor antagonist, compared with placebo in the treatment of men with moderate to severe, symptomatic, benign prostatic hyperplasia (BPH). METHODS: Prospective, randomized, double-blind, placebo-controlled multicenter trial of 2084 patients was conducted at 15 academic regional centers and 141 community-based satellite centers. Information about the use of health care resources and non-disease-specific functional status measures was collected by a standardized telephone interview of patients at baseline and every month thereafter for 12 months. Other information, such as American Urologic Association (AUA) disease-specific functional status scores, was obtained from the patient study records. Patients had a mean age of 65.7 years (range, 46 to 94), with a clinical diagnosis of BPH. At baseline men had at least moderate BPH symptoms by AUA Symptom score (13 or more) and Bother Score (8 or more). On entry, patients at regional sites had peak urinary flow rates 15 mL/s or less and total voided urine volumes 150 mL or greater. A total of 1053 patients were randomized to terazosin and 1031 to placebo treatment. Primary outcome measures included payments for all direct medical resource consumption (inpatient care, emergency department care, outpatient care, and medications); changes in three AUA disease-specific functional status indicators, (Symptom, Bother, and Quality of Life scores), and non-disease-specific functional status measures (days of work loss, days of customary activity loss, and days of bed rest). RESULTS: Total payments for health care resource (including study drug medication), adjusted to reflect 1000 patients per treatment group, were $3,781,803 and $3,568,263 in the placebo and terazosin groups, respectively. All three AUA disease-specific functional status scores improved significantly more in the terazosin group than in the placebo group. We found no difference between terazosin and placebo in all three nonspecific functional status measures. CONCLUSIONS: Compared with placebo, terazosin therapy for moderate to severe symptomatic BPH results in approximately equivalent payments for direct medical care, better disease-specific functional status improvement, and comparable change in non-disease-specific functional status measures.

Adrenergic alpha-Antagonists↗
PubMed1986

Kinetics of [3H]MPP+ uptake in dopaminergic neurons of mouse: regional effects of MPTP neurotoxicity.

In an effort to determine the specificity of MPTP/MPP+ toxicity with respect to the dopaminergic systems, the effect of prior MPTP treatment on [3H]MPP+ uptake in the striatum and olfactory tubercle of BALB/cBy mice was examined. Kinetic analysis of [3H]MPP+ uptake indicated a reduction of Vmax values in both striatum (49%, P less than 0.05) and olfactory tubercule (26%, P less than 0.05). MPTP treatment did not significantly alter the Km in either region, although MPP+ accumulates in both olfactory tubercle and striatum, these dopaminergic systems show different sensitivity to the neurotoxicity of MPTP/MPP+.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1986

Effect of amphetamine on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in mice.

Amphetamine has been shown to either potentiate or protect against MPTP neurotoxicity. The time course of changes in dopamine and its metabolites was examined after MPTP, amphetamine, or MPTP plus amphetamine administration. Results suggest that under conditions of granular depletion and release of dopamine by 10 mg/kg amphetamine, increased MPTP neurotoxicity occurs. Amphetamine injections at 2-5 mg/kg prevents the decline in dopamine possibly by blockade of the uptake of MPP+, rather than by an inhibition of monoamine oxidase.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1986

Effect of nicotine and amphetamine on the neurotoxicity of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice.

The present results show the potentiating effect of amphetamine on the ability of MPTP to destroy dopaminergic neurons in striatum of the mouse. A single injection of MPTP (8 mg/kg, retro-orbital) reduced the binding of [3H]mazindol, a marker for dopamine terminals, by 24%. When D-amphetamine (10 mg/kg, s.c.) was given 20 min prior to MPTP, the binding of [3H]mazindol, measured 3-5 days later, was reduced by 58%. It is proposed that the mechanism of this potentiation primarily involves an increased release of dopamine by D-amphetamine, and free radical-mediated processes. Although nicotine also releases dopamine from the striatum, no effect was observed when it was administered prior to MPTP. The lack of effect is probably related to short duration of action of nicotine and the modest effect on release of dopamine as compared to that of amphetamine.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1983

Adrenergic control in three artery segments of diminishing diameter in rabbit ear.

The adrenergic neuroeffector mechanism has been assessed in three different-sized vessels of the rabbit ear, i.e., the central ear artery (CEA), which has an unstretched lumen diameter (ULD) of approximately 300 micron; a main side branch (MSB) that comes off the CEA immediately distal to the crossover position of the central vein (ULD approx 150 micron); and a terminal branch (TB) that originates from the MSB (ULD approximately 75 micron). The vessels receive adrenergic innervation limited to the adventitia as assessed by fluorescence histochemistry. Density of innervation, as indexed by neuronal uptake of tritiated norepinephrine (NE) and NE content expressed in terms of surface area of the vascular segment, appears greater in the larger vessel than in the small vessels. The neurogenic contractile response of isolated segments in relation to the maximum response to iota-NE was significantly greater in CEA than in the smaller vessels; this paralleled the neuronal density. Phentolamine (10(-6) M) blocked neurally evoked contractions of ear vessels at 2 Hz and depressed the contraction at least 90% at 4 and 8 Hz. All arterial segments constricted in response to histamine and NE with equal maximal effects. Sensitivity to NE appeared equal, whereas that to histamine appeared greater in the smaller vessels. Only the two smaller vessels possessed intrinsic tone. On the basis of the substantial innervation and neurogenic response of the vessels studied, (substantive) sympathetic control of vascular tone occurs in the three different-sized vessels of the rabbit ear, a fact that may be related to the temperature regulation role of that vascular bed.

Animals↗
PubMed1982

Red cell phospholipids in schizophrenia.

Phospholipids in red blood cells (RBCs) of schizophrenics and controls were determined. Three different RBC preparations and two different extraction methods were used. Phospholipids were separated by thin layer chromatography and by high pressure liquid chromatography, and were quantified by phosphorus analysis and by ultraviolet absorption. Findings were consistent with values previously reported for normals. However, in contrast to recent reports of elevated phosphatidylserine levels in schizophrenics' RBCs, we observed no differences between populations.

Adult↗
PubMed1976

Breath-alcohol analysis: uses, methods, and some forensic problems--review and opinion.

Breath analysis for ethanol, especially in respect to the forensic aspects, has been reviewed. Included are matters dealing with instrumentation, physiological factors involved in the elimination of ethanol via the breath, and, especially, the uncertainties in the calculation of a whole blood concentration of ethanol from the quantity found in breath. We believe that the conversion of a breath quantity to a blood concentration of ethanol, for forensic purposes, should be abandoned and that the offense of driving while under the influence of alcohol should be statutorily defined in terms of the concentration of ethanol found in the breath in jurisdictions employing breath analysis. The breath sample should be obtained and analyzed only with instruments having capabilities which would require some extension of present federal standards for evidential breath-testing devices. Events in early 1975 indicate that implementation of some of these proposals may soon be undertaken.

Accidents, Traffic↗