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Biomedical subjects

A Griffiths

Publications and source records attributed to A Griffiths.

At least 73 records · Page 4Linked to original sources
PubMed1986

Specific suppressor T cells in rats active in the afferent phase of contact hypersensitivity.

The optimal conditions for the induction of contact hypersensitivity in rats and the characteristics of its suppression were studied using the sensitizing haptens dinitrofluorobenzene (DNFB) and trinitrochlorobenzene (TNCB). The hypersensitivity was shown to be hapten specific in so far as TNCB did not sensitize for DNFB responses but sensitization with DNFB did allow a marginal response in rats challenged with TNCB. Suppression of the sensitization to DNFB and TNCB could be generated by intravenous injection of dinitrobenzenesulphonic acid (DNBS) or trinitrobenzenesulphonic acid (TNBS), respectively, up to 3 weeks before sensitization. This suppression was hapten specific and could be transferred with splenic T cells enriched for lymphocytes carrying the OX8 (Tc/s) cell marker. Only the induction phase of sensitization, however, could be suppressed in that way. No suppression acting upon the effector phase could be detected except for a nonspecific local suppression at the site of a previous challenge with an antigen to which the rat was specifically suppressed. This study shows that suppression of contact hypersensitivity in rats is mediated by specific suppressor T cells of which the activation pathway apparently differs from that postulated for mice.

Animals↗
PubMed1985

Juvenile plantar dermatosis. A clinicopathologic study.

Fifty-six patients had juvenile plantar dermatosis (JPD). The plantar surface of the toes and the anterior third of the sole were the sites most commonly affected. Less commonly affected were the dorsal surface of the toes and the fingertips. No seasonal variation was found, and treatment was generally ineffective. Preventative measures had no influence on the course of the condition. Histopathologic features included psoriasiform acanthosis, with focal loss of granular cell layer, and uniform parakeratosis. Distinctive features included a tendency for the dermal infiltrate to localize around sweat ducts at their point of entry into the epidermis. In addition, inflammatory changes within the epidermis were localized mainly to the acrosyringium and included paranuclear vacuolization of epidermal keratinocytes, spongiosis, and slight spongiotic vesiculation. These changes are similar to those described in other eczematous conditions, and there is little evidence to suggest that disordered sweating plays a primary role in the pathogenesis of JPD.

Adolescent↗
PubMed1984

Forearm arterial distensibility in systolic hypertension.

It is unclear whether the stiffened arterial tree in systolic hypertension is the cause or the effect of the disease. In this study, brachial and radial arterial pulses were sensed by external Pixie transducers and measurements of pulse wave velocity converted to volume distensibility using the Bramwell-Hill equation. Blood pressure was controlled as a variable by repeating the measurements at a variety of transmural arterial pressures. This was accomplished by encasing the forearm in a rigid plastic cylinder within which pressures were varied. Twenty-nine patients with systolic hypertension were compared with 22 age-matched control subjects. At ambient pressures the volume distensibility of patients was lower than that of control subjects (0.10 versus 0.18% delta volume/mm Hg, p less than 0.001) but there was no difference in volume distensibility between the two groups at any comparable transmural pressure. Nineteen patients were treated for 1 month with a thiazide diuretic agent and the studies were then repeated. Systolic and diastolic blood pressure decreased significantly and volume distensibility increased (0.10 to 0.15% delta volume/mm Hg, p less than 0.001) at ambient pressures. But at comparable transmural pressures, volume distensibility was unchanged. It is concluded that, in the forearm, increased arterial stiffness is the result and not the cause of systolic hypertension, but these data cannot exclude increased aortic stiffness as a significant factor. Thiazide diuretic drugs increase forearm arterial compliance by lowering blood pressure without a demonstrable drug effect on this arterial wall.

Aged↗
PubMed1984

A clinical trial of single dose rectal and oral administration of diazepam for the prevention of serial seizures in adult epileptic patients.

The clinical anticonvulsant efficacy of single dose rectal and oral administration of diazepam 20 mg was examined in two double-blind placebo-controlled trials in adult epileptic patients. All subjects suffered from drug resistant epilepsy and frequently experienced serial seizures. Diazepam was administered rectally as a new experimental suppository formulation immediately after a seizure and was highly effective in preventing recurrent fits within a 24 h observation period (p less than 0.001). Pharmacokinetic studies revealed a wide range of serum diazepam concentrations 60 min after administration of the suppository (mean serum diazepam level 190 +/- 73 (SD ng/ml). In a similar study oral administration of diazepam 20 mg significantly reduced the incidence of serial seizures compared with a placebo (p less than 0.01) and the mean 60 min serum diazepam level was 273 +/- 190 (SD) ng/ml.

Administration, Oral↗
PubMed1983

[Pensions for the aged or housebound: discriminant factors. Study conducted in 4 districts of the canton of Fribourg (Switzerland)].

This research forms part of a two centre study (Fribourg et Geneva) on the use of medical and socio-medical services by elderly persons. It was undertaken under the auspices of the national research programme No 8 (Efficiency and effectiveness of the Swiss health system). The study covered 1173 persons aged 65 years or over receiving care in three services (partly medicalized nursing homes, retirement homes and home nursing services) in four french speaking districts of Fribourg Canton. The staff of these services provided cross sectional data on the personal characteristics of their clients or patients, their physical and mental capacities, the specific services provided to them, and some indications on their home circumstances. The results show differences between districts and services in terms of the overall utilisation rate, its structure, and the detailed profiles of specific needs and services. The discussion focusses on the possible interpretations of these differences and on the fundamental problem matching services to needs.

Aged↗
PubMed1983

[Recourse to health care and drug consumption. Perspectives and conceptual framework].

This paper is based on an introductory review given at the seventh scientific meeting of the Association of French Speaking Epidemiologists on "Epidemiological Aspects of the Consumption of Pharmaceuticals". It notes that though there is a relatively close relationship between total health service spending and Gross Domestic Product, no such relationship exists for expenditures on the different components of health services. Countries with similar morbidity pyramids, economic and technical capacity have quite different pyramids of service. Pharmaceutical expenditures also show this variation. In 1975, a comparative survey showed that they varied from 0.68% of G.D.P. in Denmark to 1.89% in Italy, and from $28.6 per head in the United Kingdom to $90.9 in France. The largest variation is in the share of health expenditures allocated to pharmaceuticals, which though falling generally in developed countries, ranges from 9% in Sweden to 36% in Italy. Given these variations, a synthetic schema is outlined relating need, demand and use of health services, including pharmaceuticals. This schema is then elaborated to include the main factors influencing demand and use. They include 21 predisposing factors, (10 morbidity factors, 11 social and personal factors) and 4 enabling factors. Each of these factors is briefly explained. The conclusion is drawn that though the factors influencing pharmaceutical consumption are known, neither their respective influences nor their interactions are known. Epidemiological research has so far hardly scraped the surface of this problem, and the bulk of the work required in this field still remains to be done.

Adolescent↗
PubMed1981

[Evaluation and decision making. The economist's point of view (author's transl)].

This brief review summarizes six fundamental points concerning the practical application of evaluation results by decision makers. 1. Areas of agreement and disagreement between the viewpoints of doctors and economists; the necessity and the possibility of reconciling them by a systematic but flexible approach. 2. Basic factors which oblige us to seek this reconciliation between clinical responsibility to the patient and economic responsibility to society. 3. The concept of economic efficiency and the three types of economic analysis for achieving, it which are the most closely linked to epidemiology. 4. Some evidence of the lack of economic efficiency in the health services, and the slowness of improvements. 5. Five types of difficulties in the use of evaluation results by decision makers. 6. Some pragmatic propositions to improve the situation.

Cost-Benefit Analysis↗
PubMed1980

Quality control in drug measurement.

Therapeutic drug monitoring of serum concentrations has become a rapidly expanding area of clinical pharmacology and is likely to remain an important growth area in the future, despite that the evidence for the efficacy of such monitoring is inconclusive except for a handful of drugs and findings that the reliability of much drug assay work is far from optimal. Nonetheless, in view of the likelihood that the use of routine monitoring will increase, the institution of quality control programs seems not only desirable, but necessary. We describe the design of Bartscontrol (formerly known as St. Bartholomew's Hospital Quality Control Scheme for Antiepileptic Drugs) and discuss the experience of this program. Although the feedback provided to the participants of such a program seems to encourage an overall increase in precision, our findings also indicate that some laboratories perform consistently badly. While the data generally do not reveal that variations in precision are due to analytical method employed, a scheme such as the one described can occasionally make the important finding that a particular technique is inappropriate, as was found for the case of spectrophotometry for phenytoin.

Anticonvulsants↗
PubMed1980

Acrokeratosis paraneoplastica--a new cutaneous marker of malignancy.

The historical background and the main clinical features of a specific paraneoplastic dermatosis, acrokeratosis paraneoplastica, are reviewed. Typical features are erythematous scaly lesions on the extremities, ears and bridge of the nose, associated with a malignancy, most frequently in the laryngopharyngeal region.

Humans↗
PubMed1980

The sensitivity of urinary isolates to cefuroxime, a new beta-lactamase stable cephalosporin.

The sensitivities to cefuroxime and cephaloridine were compared in 500 bacterial isolates from consecutive cases of urinary tract infection. In the first 200 organisms there was generally good correlation between the diameters of the zone of inhibition around a 30 microgram cefuroxime disc and the MICs. Correlation was poorest with streptococci. From the preliminary observations, criteria were derived to relate the disc sensitivities to MICs for all 500 strains. Neither cephalosporin had significant activity against Pseudomonas spp. but, apart from one strain of Klebsiella and one methicillin-resistant staphylococcus, the only bacteria sensitive to cephaloridine but resistant to cefuroxime were Str. faecalis. Of the 500 organisms, 45% were beta-lactamase-producing Gram-negative bacilli and, overall, cefuroxime was more active than cephaloridine against them. The greater stability of cefuroxime to the beta-lactamases from these bacilli were also supported by a smaller increase in MIC when the inoculum size was increased. On the basis of these results, cefuroxime should prove an effective choice for the treatment of most urinary tract infections.

Bacteria↗
PubMed1977

Comparative acitivity of ampicillin and cefuroxime against three types of Haemophilus influenzae.

On the basis of their susceptibility to ampicillin, strains of Haemophilus influenzae can be divided into three types: type 1 are normally susceptible strains, type 2 produce stable spheroplasts from low inocula, and type 3 are beta-lactamase producers. Because of the production of spheroplasts, standard broth and agar dilution techniques have failed to differentiate between the responses of type 2 and 3 strains to ampicillin, or to identify the superiority of cefuroxime over ampicillin against the beta-lactamase-producing strains. Disk susceptibility tests with heavily seeded plates were also difficult to interpret. To overcome these problems, we developed a medium that supports the growth of H. influenzae, but not survival of spheroplasts, thereby reducing the complicating influence of spheroplast formation. Utilization of the medium made it possible to identify beta-lactamase-producing strains via both minimal inhibitory concentration and disk susceptibility techniques, as well as the superiority of cefuroxime over ampicillin against such strains. In vivo experiments showed that cefuroxime and ampicillin are equally active against infections with type 1 and 2 strains, but that cefuroxime is superior to ampicillin against infections with type 3 beta-lactamase-producing strains.

Ampicillin↗