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Biomedical subjects

D Thomas

Publications and source records attributed to D Thomas.

At least 847 records · Page 47Linked to original sources
PubMed1984

Acute lower respiratory tract infections in children: possible criteria for selection of patients for antibiotic therapy and hospital admission.

Acute lower respiratory tract infections are a common cause of morbidity and mortality in children in the less developed countries. Considering the urgent need for rational protocols for the management of these infections in children and how little is known about the clinical signs that might predict the need for antibiotic therapy in a primary health care setting, a prospective study of the clinical signs in 200 paediatric outpatients presenting with a cough, 100 age-matched controls without cough, and 50 children admitted to hospital with pneumonia was carried out.In children with cough, a respiratory rate greater than 40 or 50 per minute (or a qualitative impression of tachypnoea) is probably the best indicator of the need for starting antibiotic treatment by primary health workers. The presence of fever appeared to be a poor guide to the need for antibiotic therapy. The presence of chest indrawing is, however, a reliable indication that a child with cough should be admitted to a health centre or a hospital. Further prospective studies are needed to determine the ability of these clinical signs to predict the course of these infections.

Acute Disease↗
PubMed1984

[Neonatal infection caused by the beta-hemolytic streptococcus of group B: review].

This review of the literature on the pathogenicity of B group beta-haemolytic streptococcal infection in perinatology first describes the clinical symptomatology of the illness in the newborn and its incidence. One per cent of all babies born to mothers with the infection are seriously affected themselves. Between one and three infants per thousand births die of it. B Group beta-haemolytic streptococcus is, together with E. Coli, the principal cause of neonatal death from infection. The techniques for identifying the bacteria are more reliable when the appropriate transport media and the selected culture media described in the text are used. The different therapies that have been put forward by different authors are described together with their results. In the conclusions reached the essential features that can be used to serve as a guide for the clinician in his choice of preventive or curative therapy are pointed out.

Age Factors↗
PubMed1984

[Role of echography in the diagnosis and monitoring of hepatic alveolar echinococcosis].

By means of a review of a series of 30 cases of hepatic alveolar echinococcosis, the authors propose a classification of the various sonographic patterns; they point out the heterogeneous form which associate necrosis and calcification inside an hyperechoic mass and is the most frequent. The interest of ultrasonography for detection of lesions, its limits for diagnosis of extension, the contribution of percutaneous biopsy are discussed, as its place in the survey of the affection.

Adult↗
PubMed1984

[Interatrial septal aneurysm. Echocardiographic diagnosis].

Interatrial septal aneurysm is a rare abnormality and can now be diagnosed by echocardiography. We report the case of a 52 year old woman in whom this condition was diagnosed after an embolic cerebrovascular accident. M mode recordings showed a linear echo in the left atrial cavity in early and mid systole. The aneurysm was directly visualised by 2D echo as a hemispherical bulge in the mid portion of the interatrial septum, which was mobile and had a to-and-fro motion between the two atria in relation to the different phases of the cardiac cycle. The diagnosis was confirmed by angiography, and at surgery. A feature of this case was the close correlation between echocardiographic, angiographic and operative findings. The pathogenesis of this type of aneurysm remains conjectural as does its role in the production of cerebral embolism, the evidence for which was circumstantial in the absence of other demonstrable causes and in the light of previously reported cases.

Angiography↗
PubMed1984

[Effect of various antiseptics on Chlamydia trachomatis].

We compared the activity of different antiseptics (chlorhexidine, picloxidine dichlorhydrate, povidone-iodine, and noxythiolin) on Chlamydia trachomatis using two techniques. In the first, an antigenic preparation obtained from a Chlamydia trachomatis-infected cell culture was used. Different times of contact and different concentrations were studied. The antigen-antiseptic mixture was inoculated on healthy cell cultures and infected cells were counted 48 hours later. In the second technique, previously infected cells were incubated with antiseptics at different concentrations for 48 hours. Results are given as a percentage of infected cells. Chlorhexidine and picloxidine dichlorhydrate have a rapid action on Chlamydia trachomatis. Noxythiolin requires a longer period (2 hours) to be active. Povidone-iodine exhibits no activity on Chlamydia trachomatis.

Anti-Infective Agents, Local↗
PubMed1984

The correlation between carotid plaque ulceration and cerebral infarction seen on CT scan.

The purpose of the study was to determine the association between cerebral infarction seen on CT scan and macroscopic ulceration of atheromatous carotid plaques in patients undergoing carotid endarterectomy. Following carotid endarterectomy in 65 patients, specimens were examined for the presence of ulceration without knowing the result of the preoperative CT brain scan. The 65 patients thus investigated underwent 68 carotid endarterectomies: 36 for a history of transient ischemic attacks (TIAs), 13 for amaurosis fugax, and six for prior strokes; 13 asymptomatic patients had prophylactic carotid endarterectomy prior to coronary bypass. A macroscopic ulcer was present in 42 specimens. Twenty-six (62%) of the patients with ulceration had one or more ipsilateral cerebral infarcts on CT scan. Only two (8%) of the 26 patients without an ulcer had cerebral infarcts. Of the 36 patients who presented with TIAs, 26 (72%) had carotid plaque ulcers and 23 (88%) of these had cerebral infarcts on CT scan also. In contrast, only three of 13 asymptomatic patients had plaque ulcers and only one of these had a cerebral infarct. There is a high incidence of cerebral infarction seen on CT scan in patients presenting with TIAs. These infarcts occur predominantly in patients with ulcerated atheromatous carotid lesions.

Aged↗
PubMed1984

Use of immobilized enzyme coupled with an electrochemical sensor for the detection of organophosphates and carbamates pesticides.

The feasibility of an acetylcholinesterase electrode to detect pesticides is shown. The enzyme electrode is produced by coupling an electrochemical sensor (a slightly modified pH glass electrode) and an enzymic layer. Carbaryl (I) and azinphosethyl (II) are used as examples; typical recordings of the electrode signal and calibration curves are presented. The measurements were taken directly with inhibitor in the presence of substrate (I) or after incubation of the enzymic film (II). The electrode behavior can be modulated by varying the amount of enzyme immobilized in the film and by varying the concentration of substrate used during measurement. For I, the detection level is about 1.0 ppm and I50 = 6 10(-6) M, with acetylcholine as substrate. For II, the detection level is 1 ppm and I50 is dependent on the time of incubation. This new type of pesticide sensor could be used in air and water pollution control and is intended to be complementary to existing analytical methods.

Acetylcholinesterase↗
PubMed1983

[Diagnosis and evaluation of isthmic coarctations of the aorta by bidimensional echocardiography].

Two cases of thoracic aortic coarctation seen on the suprasternal incidence of bidimensional echocardiography are reported. In one case, the observed echocardiographic image is an obstruction of the vascular lumen. In the other there is only reduction of the vascular calibre. In both cases, a complete examination of the aortic arch and its major branches, substrictural aortic region, and cardiac valves was obtained. The echographic results were concordant with those of the angiography, except for an underestimation of the severity of the thoracic stenosis in the second case, with the echography. An echographic post-operative control in the first case showed normalization of the vascular calibre in the isthmus region. Echocardiography allows visualization of thoracic aortic coarctations and examination of associated vascular and cardiac lesions. However, problems remain in the quantification of stenosis, which are inherent to the technique.

Adolescent↗
PubMed1983

Assay of AHF concentrates and standards: failure to eliminate variability with a monographed assay.

Previous calibration studies have shown a high interlaboratory variability in the potency of the proposed Office of Biologics (National Center for Drugs and Biologics, US-FDA) AHF standard relative to the 2nd International Standard for Factor VIII (Factor VIII:C) (WHO 73/552). This led to the formation of an Industry Collaborative Study group whose objective was to reduce the assay variability. The group, in collaboration with the Office of Biologics and the National Institute for Biological Standards and Control (UK), designed a study based on a monographed one-stage assay protocol, which specified all materials, assay methods, equipment, dilution technique, reagents, assay order, and calculation methodology. All participants received common reagents and samples, with the exception of substrate plasma. It was felt that substrate plasma could not be a common reagent in a monographed assay. However, each laboratory prepared substrate plasma according to the protocol. All data were analyzed by an independent statistical staff. Preparations assayed included two 10-donor plasma pools, the 2nd International Standard for Factor VIII (WHO 73/552), the proposed OoB Lot A internal standard, the participants' own house standards, and commercial AHF concentrate material. The results show a statistically insignificant reduction in the interlaboratory variability, but intralaboratory consistency was generally maintained. The study shows that monographing an assay for Factor VIII.

Adolescent↗
PubMed1983

Experimental evidence and theoretical discussion for long-term oscillations of phosphofructokinase in a compartmentalized system.

The activity of rabbit muscle phosphofructokinase (EC 2.7.1.11) has been followed as a function of time under conditions where the enzyme is separated from the bulk solution by an inert membrane. An enzymatic coupling assay allows continuous measurement of the variations in NADH concentration, which is directly related to the enzyme catalytic activity. For given concentrations of substrates (ATP and Fru6P) in the outside reservoir and a given ratio between diffusion coefficients of both substrates, the activity of phosphofructokinase exhibits an oscillatory behavior during a period of about 5 h. The phenomenon is explained in terms of coupling between diffusion of metabolites and non-linear enzyme reaction.

Animals↗
PubMed1983

Pharmacokinetics of aspirin and salicylate in elderly subjects and in patients with alcoholic liver disease.

Plasma aspirin, salicylate and salicyluric acid concentrations were monitored in young, elderly and alcoholic subjects after ingestion of a single 1.2 g dose of soluble aspirin. The plasma aspirin, salicylate and unbound salicylate concentration-time profiles varied considerably between individual subjects. Most of the pharmacokinetic parameters derived from these profiles were not significantly different between young subjects, elderly subjects and subjects with alcoholic liver disease. Individual plasma albumin concentrations provided a better index of the unbound plasma salicylate clearances and salicylate plasma protein binding than the age of the subject or the presence of alcoholic liver disease. Highest unbound plasma salicylate concentrations were found in subjects with the lowest plasma albumin concentrations.

Adult↗
PubMed1983

Carminomycin vs adriamycin in advanced soft tissue sarcomas: an EORTC randomised phase II study.

Eighty-three patients with advanced soft tissue sarcoma who had received no prior chemotherapy entered a randomised phase II study comparing carminomycin (CMM) 20 mg/m2 with adriamycin (ADM) 75 mg/m2, both administered i.v. bolus every 3 weeks. Six patients were ineligible and response could not be evaluated in 6 additional patients. Thirty-eight evaluable patients received ADM and 33 received CMM. There was one complete response to ADM and 10 partial responses, an overall response rate of 29%. CMM showed significantly (P = 0.01) lower antitumour activity--one partial response (3%). Stabilisation of disease was similar in both arms (47 and 45%), but fewer patients progressed on ADM (24 compared to 52%). Durations of response dating from the start of chemotherapy were 5 months for complete remission on ADM, a median of 7 months (range 4-17) for partial response on ADM and 14 months for the one partial remission on CMM. Although the median time to progression for all patients receiving CMM (2 months) was significantly (P = 0.001) shorter than for those receiving ADM (5 months), patients on ADM had only a marginally significant longer duration of survival (P = 0.06) than the patients receiving CMM. A leucocyte nadir less than 2.0 X 10(9)/l occurred in 38% of patients receiving ADM and 43% receiving CMM. Anaemia and thrombocytopoenia were uncommon. Other toxicities such as nausea, vomiting, anorexia and alopecia were more severe in the ADM group. There was one infective death secondary to leucopoenia in the ADM arm, and one patient who had received 109 mg/m2 CMM + 255 mg/m2 ADM developed progressively fatal cardiomyopathy.

Adolescent↗