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Biomedical subjects

S H Roth

Publications and source records attributed to S H Roth.

At least 127 records · Page 7Linked to original sources
PubMed1986

A multicenter study of annual health service utilization and costs in rheumatoid arthritis.

The economic impact of chronic illness has important implications for medical practice and health policy. To determine the yearly costs of illness for those who have rheumatoid arthritis, a detailed, self-administered questionnaire was developed. The questionnaire was completed by 940 patients. Direct costs (recorded as charges) include the average annual expenditures by all patients and third party payers for: hospital care ($913), physician costs ($206), other health professional visits ($71), medications ($436), laboratory tests ($217), radiographs ($116), assistive devices ($24), and nontraditional therapies ($22). The total annual medical costs per patient were $2,533. In a multivariate analysis that controlled for age, sex, education, and disease duration, the outpatient costs, inpatient costs, and total costs were all positively related to the Health Assessment Questionnaire Disability Index (P f less than 0.01) and global health (P f less than 0.01), but were not associated with self-reported pain.

Arthritis, Rheumatoid↗
PubMed1986

Impact of specific therapy upon rheumatoid arthritis.

We performed a prospective, parallel, descriptive study of 737 consecutive new uses for 11 drugs prescribed for patients with definite or classic rheumatoid arthritis. The patients were from 5 geographically dispersed sites. Researchers used validated outcome assessment instruments to measure endpoints of disability, pain, patient global assessment, medication costs, laboratory costs, and number of physician visits. Patients were studied by strict prospective protocol at 6-month intervals for 3 years. Controls included parallel results with other drugs, and before and after values for the individual patient. Beneficial effects were observed with the "disease-modifying" drugs: intramuscular gold, penicillamine, and methotrexate. Of these, gold had the most apparent effect. An average of 9 months of gold therapy resulted in highly significant reductions in disability (P less than 0.005), pain (P less than 0.001), and patient global assessment (P less than 0.005). However, patients receiving gold and methotrexate had nearly twice as many visits to physicians. In addition, drug costs increased strikingly with gold, and laboratory costs tripled. Relatively minor differences among nonsteroidal antiinflammatory agents were difficult to interpret. The outcome assessment techniques used in the study are sensitive measures, which confirm the results of experimental studies and extend observations to new outcomes, including cost and disability.

Anti-Inflammatory Agents↗
PubMed1986

Differential actions of volatile anaesthetic agents on a single isolated neurone.

The precise mechanism(s) and site(s) of action of general anaesthetic agents remain a mystery. The early theories of anaesthesia concentrated on a unitary mechanism; however, many recent investigations emphasize specific interactions between anaesthetic agents and excitable membranes. In this study volatile anaesthetics (halothane, isoflurane, enflurane and diethyl ether) applied as vapours in clinical concentrations were observed to produce differential effects on the discharge activity of an isolated crayfish neurone. In addition, both enflurane and diethyl ether induced bursts of discharge activity at concentrations known to produce EEG seizure activity in animals and man. These observations do not support the concept of a common non-specific mechanism of action, but provide further evidence that the action of volatile anaesthetics is selective and may involve multiple sites or mechanisms, or both.

Action Potentials↗
PubMed1986

Is drug-induced membrane stabilization a selective or a non-specific phenomenon?

In his review of 1958, Shanes described stabilizers as agents which decrease or reduce an increase in the ionic permeability of excitable membranes, thus preventing a change in membrane potential or excitability. A large variety of compounds, including anaesthetics, can produce this pharmacological activity. Lipid solubility of the active compounds appears to be the major requirement and since these compounds are structurally unrelated, earlier theories of mechanism emphasized a common physical (non-specific) mode of action. This implies that specific sites and/or receptors are not involved. The interaction with hydrophobic sites results in a perturbation measured as fluidization or expansion of membrane components such as lipids and/or proteins. The perturbation would induce, either directly or indirectly, conformation change of ionic channels producing a decrease of induced depolarization (stabilization). There is considerable evidence, however, which does not support a common, non-specific mechanism of action for all excitable membrane stabilizers. The hypothesis that drug-induced membrane stabilization is selective and dependent on molecular structure in addition to lipid solubility is evaluated. Studies using in vitro neuronal preparations will be discussed which clearly demonstrate that stabilizers can differentially alter properties and function of neuronal membranes.

Animals↗
PubMed1986

A multicenter study of hospitalization in rheumatoid arthritis: effect of health care system, severity, and regional difference.

During 1981, centers in Phoenix, Saskatoon, Stanford and Wichita monitored hospitalizations for 816 patients with rheumatoid arthritis. Admission rates varied 2-fold, and admissions for evaluation and treatment 10-fold across centers. Admissions were related primarily to disease severity, but in US centers, were reduced by a factor of 3 by prepaid health care. Length of stay was shortest in California (7.3 days), and longest in Saskatoon (16.3) where designated arthritis beds and government prepaid health care existed. Average charges for surgery were as high as $10,000 in Phoenix and as low as $4550 in Wichita. Charges and length of stay were unrelated to disease severity, but were responsive to health care delivery system, availability of facilities, and geographic and center variation.

Arizona↗
PubMed1985

Benzodiazepines produce contrasting effects on the active membrane properties of an invertebrate neuron.

A perturbation of excitable membranes mediated by non-receptor (non-specific) mechanisms might be predicted from the hydrophobic nature of 1,4-benzodiazepines. Since correlations between membrane properties and neuronal effects have not been described for benzodiazepines, the effects of flurazepam, oxazepam and the benzodiazepine antagonist flumazepil (Ro 15-1788) were examined on both passive and active electrical properties of the membrane and neuronal discharge frequency. In this study, the isolated sensory neuron of the crayfish has been utilized as a neuronal model system. Flurazepam and flumazepil both enhanced the discharge frequency, in contrast to the depression produced by oxazepam. Discharge frequency was directly correlated with the maximum rate of rise of membrane potential during the threshold phase and was inversely correlated with spike threshold. In addition, the discharge frequency appeared to exhibit little dependence on peak amplitude, duration and the maximum rate of depolarization of the action potential. These findings are discussed in relation to non-specific mechanism(s) of action for benzodiazepines. It is suggested that, in the absence of a specific drug-receptor interaction, benzodiazepines in larger concentrations (greater than or equal to 50 mumol/l) exhibit selective membrane perturbations.

Action Potentials↗
PubMed1984

Synaptic and non-synaptic actions of benzodiazepines on the crayfish sensory neuron.

On the stretch-induced discharge activity of the isolated crayfish sensory neuron flurazepam (less than or equal to 3 X 10(-4) M) and Ro 15-1788 (less than or equal to 10(-3) M) produced reversible concentration-dependent excitation, but oxazepam only produced depression (less than or equal to 5 X 10(-4) M). Similar divergent effects on the membrane properties were observed. Oxazepam increased the threshold to firing without changing resting potential, membrane resistance or the GABA-mediated IPSP. In contrast flurazepam and Ro 15-1788 produced a concentration-dependent decrease in threshold. Flurazepam did not alter membrane resistance or resting potential but facilitated GABA transmission. Ro 15-1788 had the opposite effect on the GABA synapse, and also depolarized the resting potential but did not alter membrane resistance. The change in spike threshold appeared to be an important component in producing discharge excitation or depression. These results not only demonstrate the capability of the sensory neuron to discriminate between structures of benzodiazepines, but also that these agents can produce divergent effects on synaptic and non-synaptic properties of a single neuron.

Action Potentials↗
PubMed1984

Evidence for excitatory and depressant non-receptor-mediated membrane effects of benzodiazepines in the crayfish.

Oxazepam produced a significant reversible monophasic concentration-dependent (50-500 mumol/l) depression of stretch-induced discharge frequency of the isolated crayfish sensory neuron. In total contrast, flurazepam (10-200 mumol/l) evoked reversible excitation of the neuronal firing rate but at concentrations greater than 300 mumol/l it induced transient excitation followed by secondary total depression. The benzodiazepine antagonist flumazepil (less than or equal to 1 mmol/l) also produced an inherent increase in neuronal discharge frequency, though respective concentrations of 50 and 100 mumol/l failed to block flurazepam-excitation or oxazepam-depression. It is suggested that these high concentration qualitatively divergent neuronal effects are not mediated through specific benzodiazepine receptors.

Animals↗
PubMed1984

An in vitro study of copper and copper chelators on the crayfish stretch receptor.

This study demonstrates the effects of micromolar concentrations of copper on the discharge firing activity of the isolated crayfish stretch receptor. Different pharmacological profiles of action were obtained with the divalent (cupric) and monovalent (cuprous) salt solutions. Cupric solutions produced a concentration-dependent triphasic effect (depression-excitation-depression); in contrast, a monophasic effect (depression) was produced by cuprous solutions. The effectiveness of copper chelators, in reversing these effects, were compared with normal physiological solution. Only the first phase of the effects of cupric were partially reversed with physiological solution or ethylenediamine tetraammonium (EDTA). In the presence of D-penicillamine and triethylene tetramine (trien), all phases of the effects of both cuprous and cupric salts were completely restored to control values. In addition, copper was shown to be the most neurotoxic divalent cation examined. The results demonstrate that effects of copper on neuronal activity are dependent on time, concentration and valency state.

Animals↗