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Biomedical subjects

M Thomas

Publications and source records attributed to M Thomas.

At least 793 records · Page 44Linked to original sources
PubMed1984

Heterospecific transformation in the genus Haemophilus.

The relationship between nine Haemophilus species and Haemophilus influenzae was studied by DNA-DNA hybridization, by transformation of H. influenzae to streptomycin resistance with heterospecific DNA, by competition of heterospecific DNA for transformation by homospecific DNA and by the lethal effect of heterospecific DNA on competent H. influenzae. H. parainfluenzae, H. parasuis, and H. aegyptius DNA transformed at more than 10% efficiency when compared to homologous transformation, but only H. aegyptius demonstrated, by hybridization, a relative binding ratio of more than 80%. H. aphrophilus and H. paraphrophilus DNA demonstrated a relative binding ratio of less than 30% and transformed H. influenzae at only 10(-5) the efficiency of homologous DNA, but they competed for H. influenzae transformation as well as or better than homospecific DNA. The data indicated that in some of the species sharing the common ecological habitat of the mammalian respiratory tract, sequences necessary for competition and efficient uptake into H. influenzae are present in large numbers in their DNAs, which nevertheless have little overall homology with H. influenzae DNA.

DNA, Bacterial↗
PubMed1984

Hypnotic susceptibility: a lateral predisposition and altered cerebral asymmetry under hypnosis.

Psychophysiological and behavioural evidence is reported of altered cerebral asymmetry under hypnosis in favour of the right hemisphere. This occurred in Susceptible as distinct from Unsusceptible subjects. Measures included bilateral electrodermal responses to tones and bimanual processing times for sorting letters and numbers with eyes closed. Subjects listened to a tape recording of a procedure for inducing relaxation under hypnosis. Susceptible subjects, unlike Unsusceptibles, showed lateral asymmetries in baseline conditions in favour of the left hemisphere. Electrodermal responses were larger on the left than the right hand and haptic processing times were faster with the right than the left hand. Under hypnosis there was a reduction in electrodermal orienting responses coupled with faster habituation and a reversal in lateral asymmetries. Haptic processing revealed a slowing in right hand processing times whereas left hand times were reduced as was the case with bilateral processing times in both Unsusceptible subjects and controls who experienced no hypnosis. Unlike earlier reports left hemisphere dynamic processes were fundamental to the induction of hypnosis. A neuropsychological model is proposed whereby susceptibility is associated both with a left bias prior to hypnosis and left hemisphere inhibition under hypnosis. Unsusceptibles retain a right hemisphere orientation without undergoing left hemisphere inhibition. Thus hypnosis involves an inhibition of left-sided processes which permits the ascendancy of the right hemisphere through the attenuation of left hemisphere control.

Adolescent↗
PubMed1984

Recurrent carotid artery stenosis following endarterectomy.

Spectral analysis was used to examine 257 carotid arteries in 227 patients who had undergone carotid endarterectomy at 1, 3, 6, and 12 months after surgery and annually thereafter. Routine intraoperative completion angiography ensured that the operations were technically satisfactory. Postoperative restenoses were identified in 38 patients (15%). In 23 arteries (9%), the restenosis exceeded a 50% diameter reduction while in 15 arteries (6%) the stenosis was less than 50% of the diameter. Restenosis developed in 24/96 women (25%) and 14/161 men (9%). Twenty-nine (70%) stenotic lesions occurred within 12 months. In three patients early lesions regressed. Reoperation with patch angio-plasty was required in six patients. When the 219 carotid arteries that remained widely patent were compared to the 38 that restenosed , no differences were noted for age, diabetes mellitus, hypertension, smoking, or degree of preoperative stenosis. Early stenotic lesions appear to be due to myointimal hyperplasia, which is probably platelet mediated. The predominant female sex distribution may be explained by differences in platelet responsiveness in men and women.

Arterial Occlusive Diseases↗
PubMed1984

Low molecular weight IgM in B cell lymphoproliferative disorders.

Circulating low molecular weight (LMW) IgM was demonstrated in five of 38 patients with B cell lymphoproliferative disorders. These five patients all had malignant disease and could be subdivided into two groups. In the first group were three patients, each with an associated serum IgM paraprotein; two had Waldenström's macroglobulinemia, and one lymphocytic lymphoma. The two patients of the second group did not have IgM paraproteins; one had lymphocytic lymphoma and one chronic lymphocytic leukemia. Both these patients also had acquired C1 esterase inhibitor deficiency, a previously recognised association with circulating LMW IgM. None of the 16 patients with benign IgM macroglobulinemia had circulating LMW IgM. In those positive sera with LMW IgM this moiety contributed between 10.5% and 37.5% of the total IgM. There was no apparent association between LMW IgM and total IgM levels, kappa/lambda typing or the presence of Bence Jones proteinuria, but rheumatoid factor, immune complexes and cryoglobulins occurred in many of the sera which contained LMW IgM. Pokeweed mitogen stimulated peripheral blood mononuclear cells from two patients with circulating LMW IgM secreted considerable quantities of this moiety in vitro but this did not occur in two patients with benign IgM macroglobulinemia. We conclude that LMW IgM is found in the malignant but not the benign forms of B cell lymphoproliferative disorders and is frequently associated with other serological abnormalities. The basic abnormality causing defective IgM polymerisation in these disorders is obscure.

Aged↗
PubMed1984

Effect of indomethacin on cerebral blood flow, carbon dioxide reactivity and the response to epoprostenol (prostacyclin) infusion in man.

Cerebral blood flow (CBF) has been measured using a non-invasive Xenon133 clearance technique in six normal subjects after 2 days pretreatment with oral indomethacin at a dose of 100 mg/day. The results were compared with placebo given in a double blind balanced cross-over design. Indomethacin was found to result in a reduction in resting CBF of about 25% but the reactivity of the cerebrovascular circulation to carbon dioxide was preserved at normal levels. Infusions of epoprostenol (prostacyclin, PGI2) at a dose of 5 ng/kg/min resulted in a reduction of CBF of about 10% after placebo but no significant change in CBF after indomethacin. The results suggest that prostaglandins are involved in the maintenance of cerebrovascular tone but not in the mechanism of cerebral vasodilation accompanying hypercapnia. The combination of indomethacin and PGI2 has been proposed as a treatment of cerebral artery spasm and the findings suggest that the combination therapy would not be accompanied by undesirable intracerebral steal.

Adult↗
PubMed1984

Cerebral blood flow after carotid occlusion and extracranial-intracranial bypass.

Eleven patients with occlusion of one internal carotid artery showed marked reduction of regional cerebral blood flow (rCBF) through the hemisphere on the affected side with high rCBF on the opposite side. Six of the patients had no surgery, during follow-up of 2 to 5 years. rCBF increased on both sides leaving a persisting asymmetry of rCBF. Five patients had extracranial-intracranial bypass; rCBF increased on the affected side but not on the opposite side. Asymmetry of rCBF between the hemispheres remained but was much less than in the non-operated group.

Adult↗
PubMed1984

Multiple sclerosis in a Glasgow tenement.

Two males and two females brought up in the same Glasgow tenement later developed multiple sclerosis. Two of the four, a brother and sister, owned a dog who died of distemper when they were respectively eight and 12 years old.

Adolescent↗
PubMed1984

Carotid steal syndrome following carotid subclavian bypass.

Subclavian steal syndrome may result from stenosis or occlusion of the subclavian artery proximal to the origin of the vertebral artery. The diagnosis can be confirmed by noninvasive vascular studies with the use of a directional Doppler probe or by time-sequence aortic arch angiography, both of which can detect retrograde flow in the vertebral artery. A variety of surgical approaches to this condition have been used in the past, but the simpler and much safer carotid-to-subclavian bypass has become a more acceptable surgical procedure. There remains, however, a theoretical possibility that blood may be siphoned from the intracranial arteries perfused by the carotid. This phenomenon, which may be called the carotid steal syndrome, has been discussed, but no clinical cases have been reported. We present a patient who developed such a carotid steal syndrome 2 years after left carotid-subclavian bypass. This occurrence reemphasizes the importance of determining a normal carotid bifurcation prior to performing carotid-subclavian bypass.

Arterial Occlusive Diseases↗
PubMed1984

Excretion of cefuroxime in biliary disease.

Cefuroxime is a broad spectrum B-lactamase stable cephalosporin antibiotic. An intravenous injection of cefuroxime sodium 1.5 grams was administered to 45 patients after induction of anesthesia for cholecystectomy. Twenty-five patients had elective operations for chronic cholecystitis and 20 underwent urgent operations for acute cholecystitis. Of the 25 patients who underwent elective treatment, the cystic duct was patent in 13 and obstructed in 12. Antibiotic concentrations were measured by microbiologic assay in plasma, common bile duct bile, gallbladder bile and gallbladder wall. Organisms grown from the bile (Escherischia coli, eight; Proteus morganii, one; Streptococcus species, three, and Staphylococcus aureus, one) were sensitive to cefuroxime with the exception of one instance of Streptococcus faecalis. Cefuroxime levels were the same in specimens of patients with chronic or acute cholecystitis and reached therapeutic levels in the gallbladder wall, the main site of the inflammatory reaction. There was no difference in bile levels from gallbladders with patent or obstructed cystic ducts, suggesting that cefuroxime diffuses into the gallbladder and bile from the blood stream. There were no wound infections in this study when only a single dosage of antibiotic was administered intravenously.

Bile↗
PubMed1984

[Effects of a natural estrogen, estradiol, on hemostasis in guinea pigs].

17-beta-estradiol was administered weekly to female guinea-pigs at the dosage of 2-3 mg/kg body weight during 4-6 weeks. Compared to a control population, no significant effect was observed on: recalcification time; thromboelastography; PTT; APTT; Quick one stage prothrombin time; antigenic and active plasma fibrinogen level; antithrombin III level; factor XI level; red and white blood cell count. A significant increase in levels of factor II (+25%), of factor V, of factor XII (+40%) and a decrease in levels of complex VII + X was observed. Values for AT III, factor XII, chronometric and immunologic fibrinogen plasma levels, unknown until now for the guinea-pig, were established.

Animals↗
PubMed1984

[Long-term results (5-year minimum) of the diet treatment of adult obesity. Elements of weight prognosis. Apropos of 138 patients].

One hundred and thirty-eight out of 250 obese patients admitted to hospitals between 1972 and 1976 for dietetic treatment comprising 1,000 calories and 100 g carbohydrates were recontacted with a minimum follow-up of 5 years. Seventy-five patients refused to answer the questionnaire or attend an outpatient appointment. Four patients were later excluded from the study. Finally, fifty-nine patients were reassessed. The percentage of good results at 5 years (defined as greater than or equal to 5 p. 100 loss of initial body weight) was 45.5 p. 100 of those reassessed, a minimum of 20 p. 100 of the total number recontacted. The course of obesity was not linear. During the follow-up period there were 45.5 p. 100 of secondary failures (regain of initial body weight after having lost at least 5 p. 100), but also 17 p. 100 of secondary successes. The prognosis was not related to the age of onset of obesity, its duration, sex, occupation, alleged trigger factors, apparent motivation, duration of hospital admission, or treatment before or after hospitalisation. The prognosis was better in patients under 30 or over 50 years of age at the time of treatment (P less than 0.01) and when the body weight had not varied +/- 5 kg in the years preceding treatment (P less than 0.01). The following factors may also play a favourable role (but not statistically significant): the degree of obesity (better results in major obesity greater than or equal to 50 p. 100 overweight), a positive family history, the detection of a physical factor (glucose intolerance) during investigation, and the repetition of medical check-ups after initial counselling.

Adolescent↗
PubMed1983

[Detection of diabetes in obese patients. Systematic study of induced hyperglycemia with assays of blood insulin, glycosylated hemoglobin A1c and cutaneous biopsy in 46 patients].

Glycoregulation and insulin secretion abnormalities and micro-angiopathy were systematically investigated in 46 patients (6 men and 40 women; mean age 34.8) seeking medical attention for obesity. In all patients, a three-hour oral glucose tolerance test (OGTT) with 50 g glucose, with concomitant plasma insulin determinations, Hb A1c assay and skin biopsy (SB) at the medial aspect of the arm (optic microscopy study, PAS stain) were performed. We obtained 46 Hb A1c assays, 45 OGTT, 43 insulin determinations and 42 SB. In 40 patients, all four studies were available. We consider as abnormal blood glucose greater than 7.8 mmol at 120 mn with intermediate measurement greater than 10.1, insulin greater than 64 mcU with a maximum delayed after the 60th mn, Hb A1c greater than 6.3% and SB score greater than 10 (evaluating basement membrane thickness, endothelium swelling, aspect of pericytes, perivascular infiltration and percentage of capillaries involved). We observed 6 abnormal OGTT, 12 dysinsulinisms (DI), 5 Hb A1c greater than 6.3% and 17 SB greater than or equal to 10 with typical diabetic microangiopathy. Out of 40 fully investigated patients, 14 were normal for all criteria, 12 had only one abnormality (12 SB, 5 DI, 1 OGTT), 6 had 2 abnormalities (2 SB + DI, OGTT + DI, SB + OGTT, SB + Hb A1c, DI + Hb A1c) and 2 had 3 abnormalities (SB + DI + Hb A1c, OGTT + DI + Hb A1c).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Gamma-glutamyltransferase release by the post ischemic kidney: multiple forms and cellular pH.

The release of gamma-glutamyltransferase from renal tubule cells was studied in situ following 30 minutes of ischemia. The ischemic kidney enzyme level fell 33 percent after 15 minutes of reflow of which only 1.2 percent was recovered in the urine; none was released into the renal vein. At this time the overwhelming majority of the enzyme appears bound to membranes in both the kidney and the urine. In the subsequent 15 minutes renal levels continue to decline while urinary excretion accounts for 5 percent of that disappearing from the kidney. Interestingly the form of the enzyme present in kidney and urine shifts to a soluble form coinciding with cellular alkalosis, urinary alkalinization and a rise in ATP levels. Alkalinization of renal homogenates result in a 2-fold increase in the soluble enzyme form. The results are consonant with the immediate loss of brush border enzyme via uptake into the cell or release into the urine with the former pathway predominating; subsequent appearance of the soluble enzyme appears to reflect intracellular alkaline proteinase activity and exocytosis. The form in which the enzyme is excreted may provide a useful clinical index: membranous reflecting cellular necrosis and soluble reflecting cellular recovery.

Acyltransferases↗