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Biomedical subjects

M Price

Publications and source records attributed to M Price.

At least 109 records · Page 6Linked to original sources

Rigid internal fixation vs. traditional techniques for the treatment of mandible fractures.

Treatment results were compared between mandibular fractures repaired with vitallium miniplates versus intermaxillary fixation (IMF) and wire osteosynthesis in 79 patients treated over a 4-year period. The postoperative courses of 35 patients treated with 46 plates were compared to those of 44 individuals treated with traditional reduction techniques. The plated group contained nine complications (26%) versus ten (23%) in the non-plated group. This difference was not statistically significant, despite the presence of more severe fractures in the plated group. Major complications (nonunions, malocclusions) were noted in only three (8%) of the plated group; there were six complications (14%) in the non-plated group. We conclude that the plating of mandibular fractures incurs no greater overall risk of complications than traditional methods of fixation, and a lower risk of major complications, and that the advantages of plate fixation, including decreased time of intermaxillary fixation and cost effectiveness, make this the method of choice in complex mandibular fractures, even in a high-risk population.

Adult↗

The fate of elderly patients discharged from the accident and emergency department of a general teaching hospital.

This paper describes the experience of a cohort of elderly patients who were discharged after attending the accident and emergency department of a large Australian teaching hospital. Before-and-after comparisons of aspects of physical functioning revealed a considerable loss of independence in the period immediately after the visit to the hospital. Subsequent hospital admission or death was observed in 30 of the 90 patients studied. It is suggested that elderly patients discharged from the accident and emergency department are at risk and require special consideration and a high index of suspicion in terms of evaluation at the time of presentation. Before discharge, account should be taken of aspects of physical and mental function, social networks, and community supports available to each patient. A lowered threshold for admission is recommended on the basis of the high rate of return found in this study.

Activities of Daily Living↗

A comparative evaluation of oral ofloxacin versus intravenous cefotaxime therapy for serious skin and skin structure infections.

In a single-blind, placebo-controlled randomized trial, 100 successive patients were enrolled with serious skin and soft-tissue infections, whose illnesses had precipitated an initial hospital admission or an extension of inpatient care. There were 93 evaluable patients who received either ofloxacin, 400 mg orally every 12 hours plus an intravenously administered placebo every eight hours, or cefotaxime, 2.0 g intravenously every eight hours plus an orally administered placebo every 12 hours. The average length of therapy was 12 days. Both patient groups had similar demographics and underlying conditions. Wound infection was the most common diagnosis, followed by abscess, cellulitis, and trophic ulcer. Multiple pathogens were commonly isolated from infected sites (1.4 pathogens/patient). The most common pathogen was Staphylococcus aureus, followed by Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, Proteus/Providencia spp., and Enterobacter spp. Persistence of the initial pathogen at the end of therapy was observed in 22.5 percent of the cefotaxime-treated group, but in only 10 percent of the ofloxacin-treated group. There was one clinical failure in the cefotaxime group, caused by a susceptible strain of Enterobacter cloacae, and there was one clinical failure in the ofloxacin group, in which the patient had an Acinetobacter calcoaceticus var. anitratus wound infection and subsequently developed a P. aeruginosa superinfection. Adverse experiences, including rash, insomnia, and nausea, occurred in 16 percent of the patients in each group. It was concluded that oral ofloxacin is as safe and efficacious as parenteral cefotaxime in the treatment of serious skin and skin structure infections.

Administration, Oral↗

Autoradiographic analyses of agonist binding to muscarinic receptor subtypes.

The binding of four muscarinic receptor agonists to regions of rat brain was examined through quantitative autoradiographic techniques. Oxotremorine, arecoline, pilocarpine and bethanechol were chosen based on their different potencies and efficacies in muscarinic second messenger systems. Overall, the order of potency for inhibition of [3H]-l-quinuclidinyl benzilate ([3H]-l-QNB) binding to rat brain slices was oxotremorine greater than pilocarpine = arecoline much greater than bethanechol. Regional assays of agonist potency indicated that all agonists were more selective for brainstem and thalamic regions than for hippocampal and cortical regions. The high selectivity of agonists for areas such as the paraventricular thalamus and the superior colliculus, which also display low affinity for pirenzepine, suggests that muscarinic agonists bind with higher affinity to M2 receptors. Of the four agonists examined, pilocarpine displayed the lowest selectivity for M2 receptors in that IC50 values for pilocarpine were only 3-fold higher in the hippocampal and striatal regions (e.g. CA3: 40.6 +/- 9.4 microM) than in thalamic and brainstem regions (e.g. paraventricular thalamus: 14.9 +/- 6.2 microM). Oxotremorine was 8-fold more potent in the brainstem and thalamus, while arecoline and bethanechol were, respectively, 19- and 100-fold more selective for brainstem and thalamic receptors. Scatchard analyses revealed heterogeneous binding profiles for some agonists within single brain regions, suggesting that multiple agonist sites exist even within regions of predominantly M1 or M2 receptors. For example, arecoline displayed curved Scatchard plots within the external layers of the cerebral cortex, layer CA1 of the hippocampus (predominantly M1 subtype), and the paraventricular thalamus (predominantly M2 subtype). The ability of agonists to recognize multiple sites within a single region may reflect the ability to recognize receptors coupled or uncoupled to second messenger systems through G-proteins.

Animals↗

The clinician's role in competency evaluations.

The clinician's role in a competency evaluation is unclear. By reviewing the literature and analyzing the clinical process, the authors studied patient's competency to give consent to medical treatment. The authors make recommendations and have specific guidelines for the clinician doing competency evaluations. The authors emphasize the need to focus on the specific task at hand and the assessment of the patient's judgment and decision-making capacity.

Adult↗

Charybdotoxin inhibits proliferation and interleukin 2 production in human peripheral blood lymphocytes.

We demonstrate that blockade of the lymphocyte voltage-gated K+ channel by charybdotoxin (CTX) inhibits lymphocyte mitogenesis. Charybdotoxin blocks conductance with a Ki of 0.3 nM and inhibits mitogen- and antigen-stimulated proliferation with a Ki of 0.5 nM. As opposed to the other blockers of the lymphocyte K+ channel, the inhibition of mitogenesis by CTX can be overcome selectively by exogenous recombinant interleukin 2 (IL-2); endogenous levels of IL-2 in the culture supernatants of stimulated cells are decreased by the presence of CTX. Our results suggest that the voltage-gated K+ channel is either directly or indirectly involved in IL-2 synthesis and/or secretion.

4-Aminopyridine↗

Humoral Na+-K+ pump inhibitory activity in essential hypertension and in normotensive subjects after acute volume expansion.

Plasma from black male patients with essential hypertension was bioassayed for vascular Na+-K+ pump inhibitory activity. Halves of the same rat tail artery were incubated for two hours in boiled plasma supernates from a hypertensive patient and a paired age-, sex-, and race-matched normotensive subject and then ouabain-sensitive 86Rb uptake was measured. Ouabain-sensitive 86Rb uptake by their leukocytes was also measured. Eighteen pairs of subjects were studied. The uptakes were not significantly different in the hypertensive patients and control subjects. However, when we selected from the eighteen hypertensive patients, nine with low plasma renin activity on the day of the study, uptakes were reduced in the hypertensive patients relative to the paired control subjects. We also assayed plasma supernates from normotensive black and white male subjects before and after acute volume expansion (2.5 L saline IV + 1.5 L distilled water orally over a three-hour period) and from paired normotensive subjects before and after sham volume expansion and obtained a positive bioassay in the expanded subjects both on intraindividual and interindividual comparisons. These studies demonstrate increased vascular Na+-K+ pump inhibitory activity in the plasma of black male patients with low renin essential hypertension and in the plasma of normotensive subjects after acute volume expansion. The findings suggest that the inhibitory activity in the hypertensive subjects' plasma is related to volume expansion, relative or absolute.

Adult↗

Prostaglandin fevers in rats: regulated change in body temperature or change in regulated body temperature?

Experiments examining the effects of central injections of E-series prostaglandins (PGE) on body temperature have only been done in the light part of a light-dark cycle. The present experiments examined the characteristics of fevers in rats after intraventricular PGE2 injections in both light and dark in a 12:12 h photoperiod. In the light, the change in body temperature (Tb) after 0.5 microgram was not significantly different from the change after vehicle injection. After injection of PGE2 (1, 2, 4, and 8 micrograms), Tb rose in a dose-dependent fashion. Mean initial Tb in the light was 36.4-36.6 degrees C. Tb rose a mean of 1.5 degrees C after 1 microgram, 1.9 degrees C after 2 micrograms, 2.7 degrees C after 4 micrograms, and 3.5 degrees C after 8 micrograms PGE2. A dose of 16 micrograms gave almost identical results as 8 micrograms. In the dark, mean initial Tb was 37.4-37.7 degrees C. Tb rose less than 0.8, 1.1, 1.4, and 2.3 degrees C after 1-8 micrograms PGE2, respectively. Thus there were two distinct dose-response curves for day and night. Nevertheless, peak Tb values attained in the two conditions were not significantly different from each other at any given dose. These results show that a particular dose of PGE2 raises Tb to a particular level, largely independent of either the Tb at the time of the injection or the phase of the light-dark cycle. However, the change in Tb at any dose depends strongly on initial Tb. Therefore, we urge researchers in the pharmacology of thermoregulation to report initial and final Tb values as well as changes in Tb.

Animals↗

Receptor binding of [3H]naloxone benzoylhydrazone: a reversible kappa and slowly dissociable mu opiate.

In standard 3H-opioid binding assays, the benzoylhydrazone derivative of naloxone (6-desoxy-6-benzoylhydrazido-N-allyl-14-hydroxydihydronormorphi none; NalBzoH) inhibited mu, kappa, and delta binding at nanomolar concentrations. At concentrations as low as 1 nM, it also produced a wash-resistant inhibition of opioid binding. [3H]NalBzoH binding typically gave a ratio of total to nonspecific binding of 8:1. Binding reached steady state levels by 1 hr and was linear with tissue concentration. [3H]NalBzoH labeled two classes of sites. The binding to one was easily reversible whereas the other was not and was termed pseudoirreversible. At 25 degrees, almost 90% of [3H]naloxone binding and approximately 60-75% of [3H]NalBzoH binding dissociated over 90 min. However, the remainder of [3H]NalBzoH binding, corresponding to pseudoirreversible binding, remained constant over the next 5 hr at 25 degrees and additional studies suggested a dissociation half-life of approximately 24 hr. Competition studies indicated that the reversible binding corresponded to neither mu nor delta binding and may represent a novel subtype of kappa receptor. Pseudoirreversible binding was predominantly to a combination of both mu 1 and mu 2 receptors. Despite its extremely slow rate of dissociation, pseudoirreversible binding was not covalent inasmuch as lowering the pH to 5 or adding the GTP analog 5'-guanylylimidodiphosphate [Gpp(NH)p] completely dissociated prebound [3H] NalBzoH. The ability of Gpp(NH)p to dissociate pseudoirreversible [3H]NalBzoH binding raised the possibility that the slow rate of dissociation was related to interactions with a guanine nucleotide-binding protein.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

Kappa opiate receptor multiplicity: evidence for two U50,488-sensitive kappa 1 subtypes and a novel kappa 3 subtype.

Kappa receptor multiplicity is a complex area. We now present evidence from binding studies suggesting the existence of four kappa receptor subtypes. The guinea pig cerebellum contains high levels of U50,488-sensitive, or kappa 1, receptors. Kappa opiates (U50,488, tifluadom, Mr2034, Mr2266 and Win44,441) compete [3H]ethylketocyclazocine binding to kappa 1 receptors with kappa, values under 10 nM and Hill coefficients of approximately one, as does dynorphin A (kappa 1, 0.27 +/- 0.05 nM; Hill coefficient, 0.83 +/- 0.20, n = 4). However, competition studies with dynorphin B yield a Hill coefficient of 0.46 +/- 0.03 (n = 5) and nonlinear regression analysis of the competition curve is best fit by two sites. alpha-Neoendorphin Neoendorphin competition curves (Hill coefficient, 0.46 +/- 0.07; n = 3) also were best fit with two components. Competition studies with both alpha-neoendorphin and dynorphin B together suggest that both compounds label the same site with high affinity. Similar results were obtained using [3H]U69,593. Dynorphin B and alpha-neoendorphin competed binding with Hill coefficients of 0.45 +/- 0.04 (n = 3) and 0.59 +/- 0.09 (n = 3), respectively. These data suggest two subtypes of kappa 1 receptors in the guinea pig cerebellum: kappa 1a and kappa 1b. Classical kappa opiates and dynorphin A have high affinity for both subtypes whereas dynorphin B and alpha-neoendorphin label kappa 1b over 50-fold more potently than kappa 1a sites. [3H]Naloxone benzoylhydrazone [( 3H]NalBzoH) labels a novel, U50,488-insensitive kappa receptor subtype, kappa 3, in membranes from calf striatum, rat and mouse brain. We now have developed a relatively selective assay in calf striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

The pattern electroretinogram and visual-evoked potential in glaucoma.

The pattern electroretinogram (PERG) may reflect ganglion cell or inner retinal layer activity. The most sensitive spatial and temporal variables for testing patients with glaucoma have not yet been identified. Fifty-two glaucoma suspects, 51 glaucoma patients, and 28 normal subjects were studied with the PERG and VEP, using three repetition rates and three spatial frequencies. Fast Fourier transforms were calculated at each spatial frequency and reversal rate. An analysis of variance revealed that normals could be differentiated from ocular hypertension and glaucoma patients using the amplitude of the PERG (second and fourth harmonic). Abnormalities in phase of the PERG between groups were also detected. A discriminant analysis of all amplitude and phase data revealed that the phase shift of the response of the second harmonic at 11 alternations/s (15-min checks) and at 5.5 alternations/s (15-min checks) correctly identified 81% of the normal and 75% of the glaucoma patients. The phase shift determinations of the VEP revealed significant abnormalities using 2 and 1/2 standard deviation confidence limits. There was significant overlap in the pattern ERG amplitude and phase shift in all three groups.

Analysis of Variance↗

Ultrasound attenuation of the os calcis in women with osteoporosis and hip fractures.

Bone ultrasound attenuation of the calcaneus, and vertebral and femoral bone density measured by dual photon absorption were determined in 22 women with osteoporosis, 10 women with hip fractures, and 29 normal, age-matched controls to determine the utility of the ultrasound technique as an indicator of axial osteopenia. Vertebral and femoral neck density and bone ultrasound attenuation were significantly decreased (P less than 0.01) in the women with osteoporosis and those with hip fractures. The sensitivity and specificity of bone ultrasound attenuation was 80% at a value of 50 dB/MHz. At 90% specificity the sensitivity of bone ultrasound attenuation was 65%. The results of this pilot study suggest that ultrasound attenuation, a safe, simple, and radiation-free procedure, may be utilized as an indicator of decreased axial bone mass.

Aged↗

Irreversible opiate agonists and antagonists: V. Hydrazone and acylhydrazone derivatives of naltrexone.

We have synthesized a series of hydrazones and acylhydrazones of naltrexone. These substitutions had modest effects on competition of mu binding but many greatly enhanced the relative potency of the compounds for delta receptors. Increased delta affinity was most prominent with the acylhydrazones. Many of the derivatives elicited a wash-resistant inhibition of binding which was restricted to mu, not delta, binding sites. This wash-resistant inhibition of binding did not correlate with affinity, as determined by IC50 values, implying that the inhibition could not be explained simply by slow rate of dissociation due to increased affinity.

Animals↗

Fever alters characteristics of sleep in rats.

This study examined the effects of a fungal infection on body temperature (Tb) and sleep states. Tb and sleep were recorded in male rats for 24 hr after a saline injection and 48 hr after a subcutaneous injection of live brewer's yeast, at ambient temperatures (Ta's) of 20 degrees and 30 degrees C. Peak fevers of 1.6-3.1 degrees C occurred within 6-10 hr at both Ta's. The rats remained febrile for the next 12-24 hr. For the first 24 hr postyeast, amounts of SWS increased by 19 +/- 3% at 20 degrees C and 12 +/- 2% at 30 degrees C. Specifically, SWS was significantly increased from hr 5-8 (lights-on) and 13-24 (lights-off) at 20 degrees, and from hr 5-8 and 17-24 at 30 degrees C. Ta did not affect the changes in Tb or the changes in SWS after either saline or yeast. Duration of REMS varied with Ta after saline. After yeast, REMS increased by 21 +/- 12% at 20 degrees and decreased by 28 +/- 6% at 30 degrees C, with the net result that REMS at the two Ta's was equal during the fever. Furthermore, while the rats were febrile the normal diurnal variation in REMS was eliminated. Sleep and Tb returned to control values during the second fever day. These results suggest that an activated immune system both increases SWS and overrides the diurnal and thermoregulatory modulations of REMS.

Animals↗

The consequences of health service privatisation for equality and equity in health care in South Africa.

The trend towards the privatisation of health services in South Africa reflects a growing use of private sources of finance and the growing proportion of privately owned fee-for-service providers and facilities. Fee-for-service methods of reimbursement aggravate the geographical maldistribution of personnel and facilities, and the competition for scarce personnel resources aggravates the difference in the quality of the public and private services. Thus the growth in demand for these types of providers may be expected to increase inequality of access in these two respects. The potential expansion of medical scheme coverage is shown to be limited to well under 50% of the population, leaving the majority of the population without access to private sector health care. Even for members of the medical schemes, benefits are linked to income, thus clashing with the principle of equal care for equal need. The public funds needed to overcome financial obstacles to access to private providers could be more efficiently deployed by financing publicly owned and controlled health services directly. Taxation also offers the most equitable method of financing health services. Finally, attention is drawn to the dilemma resulting from the strengthening of the private health sector; while in the short term this can offer better care to more people on a racially non-discriminatory basis, in the long term, health care for the population as a whole may become more unequal and for those dependent on the public sector it may even deteriorate.

Black People↗

Health surveys in developing countries: the objectives and design of an international programme.

There have been calls recently for a major international effort to collect epidemiological information in developing countries. One approach to a World Health Survey is considered, namely single-round retrospective interview surveys. Surveys can contribute to the improvement of national health information systems by providing person-based, rather than episode-based, measures related to health that apply to the entire population. A programme of health interview surveys could be used to ascertain patterns of morbidity and mortality, to measure access to and use of health services and to develop and disseminate methodologies for collecting and analysing health related data. Single-round surveys could not be used to evaluate the impact of investments on health and would be of limited use for improving our understanding of the determinants of ill health. Attention is drawn to a number of conceptual, technical and logistic issues to be considered in the design of a World Health Survey.

Attitude to Health↗