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Biomedical subjects

M R Thomas

Publications and source records attributed to M R Thomas.

At least 19 recordsLinked to original sources
PubMed1992

Residual atrial septal defects following balloon mitral valvuloplasty using different techniques. A transthoracic and transoesophageal echocardiography study demonstrating an advantage of the Inoue balloon.

The incidence and severity of atrial septal defects following balloon mitral valvuloplasty have been assessed using transthoracic and transoesophageal echocardiography in 20 patients 3-36 months following the procedure. In eight patients (group A) the atrial septum was dilated with an 8 mm Olbert balloon and either a double or bifoil balloon used to dilate the mitral valve. In 12 patients (group B) the Inoue balloon, with a slimmer deflated profile, was used following dilatation of the interatrial septum with a 14 French vessel dilator. In group A, using transthoracic echocardiography, one atrial septal defect was imaged and transatrial flow detected by colour flow Doppler in five patients. In seven of the eight patients transoesophageal echocardiography clearly imaged an atrial septal defect and left-to-right shunting was demonstrated by colour flow Doppler. Valsalva contrast studies revealed residual transatrial flow in all eight patients. The mean width of the colour flow jet was 5.8 mm. In group B patients, using transthoracic echocardiography, only one patient had evidence of residual transatrial flow (demonstrated by Valsalva contrast). Using transoesophageal echocardiography Valsalva contrast studies, transatrial flow was seen in 11 of the 12 patients. However, no defects were imaged and colour flow Doppler indicated left-to-right shunting in only two patients. The mean width of the colour flow jet was 1.5 mm. Transoesophageal echocardiography with colour flow Doppler and Valsalva contrast studies therefore provides a sensitive method for the detection of residual atrial septal defects following balloon mitral valvuloplasty. Transatrial flow persists in the majority of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Comparative value of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve.

OBJECTIVE: To assess the relative merits of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve. DESIGN: Transthoracic and transoesophageal echocardiograms were prospectively performed in 35 patients being considered for balloon dilatation of the mitral valve. Echocardiograms were analysed for image quality, the assessment of valve morphology, the detection of left atrial thrombus, and the assessment of mitral regurgitation and other valvar pathology. PATIENTS: 35 consecutive patients with symptomatic dominant mitral stenosis. INTERVENTIONS: 30 eventually underwent balloon dilatation of the mitral valve by the Inoue technique. Five patients had mitral valve replacement. MAIN OUTCOME MEASURES: Echocardiographic and surgical detection of left atrial thrombus and successful, uncomplicated balloon dilatation of the mitral valve. RESULTS: Left atrial thrombus was detected in 1/35 patients by transthoracic studies compared with 6/35 from transoesophageal studies. Otherwise both techniques gave comparable results. Thrombus was confirmed at mitral valve replacement in five patients. Successful dilatation of the mitral valve was performed in 30 patients. CONCLUSIONS: Transthoracic echocardiography is a useful screening procedure but transoesophageal echocardiography is mandatory before balloon dilatation of the mitral valve for the detection of left atrial thrombus.

Adult↗
PubMed1991

Acanthoma fissuratum.

Acanthoma fissuratum secondary to the use of spectacles is a rare clinical finding associated with an ill-fitting frame. An interesting case is presented to highlight such a problem. Surgical excision of such lesions is recommended with advice to the patient regarding the suitable fitting of spectacles.

Adult↗
PubMed1991

The role of expectancy in hypnotic hypermnesia: a brief communication.

Previous research has yielded equivocal evidence of hypnotic memory enhancement. The present experiment assessed the effects of expectancy and hypnotizability on recall for videotaped material under waking and hypnotic conditions. Ss (N = 138) were informed of hypnotic induction either before (expectancy condition) or after (no expectancy condition) watching a videotaped enactment of a crime and completing an initial waking recall test (RI). Both groups then underwent hypnotic induction, and completed the test again (R2). Ss' raw recall scores were significantly greater under hypnotic than waking conditions, but this hypermnesia was not evident when scores were corrected for mere increase in rate of responding. Ss expecting later hypnosis scored significantly higher than Ss with no such expectations, but again, this difference was not evident in corrected scores. Hypnotizability of Ss was, however, related to corrected recall, with high hypnotizable Ss displaying the greatest increase in rate of responding from R1 to R2. No evidence for the hypothesized "suppression effect" underlying hypnotic hypermnesia was found.

Adult↗
PubMed1991

Effect of cholesterol deprivation on piglet small intestine and serum lipids.

Using the neonatal piglet, the effects of dietary cholesterol deprivation on growth, intestinal enzyme activity, intestinal and hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), and serum lipid were studied. Six litters of piglets were randomly assigned to one of two feeding regimens: restricted (800 ml of formula/24 h) versus unrestricted (1,200 ml of formula/24 h). Within litters, piglets were separated by sex, then randomly assigned to a formula containing low cholesterol (less than 2 mg/dl) or high cholesterol (145 mg/dl). Piglets were fed for 2 weeks. Male piglets in the restricted low cholesterol group gained significantly less weight per milliliter of formula than the restricted high cholesterol males. No effect was observed in the females. Microvillus membrane lactase activity was greater in males fed a high versus low cholesterol diet. Intestinal and hepatic HMG-CoA reductase activities and serum lipid profiles showed a trend toward compensation for dietary cholesterol deprivation but did not differ statistically between the cholesterol-fed versus -deprived groups. It is concluded that dietary cholesterol deprivation in the male neonatal pig causes alterations in growth, but no other statistically significant responses were detectable in this study.

Analysis of Variance↗
PubMed1991

Role of recombinant alpha-interferon in the treatment of advanced cutaneous malignant melanoma.

A total of 65 patients with advanced cutaneous malignant melanoma (MM) have now been treated with interferon alpha-2b (Intron A) at a dose of 10 million IU/m2 administered subcutaneously thrice weekly. Fifty-one patients were evaluable for response, and 4 of these (7.8%) achieved complete remission; 2 of these 4 remain so at 37 + and 54 + months. Six additional patients achieved a partial remission. All responders had subcutaneous, lymph node and/or pulmonary metastases only. In all responders, therapy was continued for a total of 12 months. The vast majority of patients experienced side effects, largely flu-like symptoms, mild leukopenia and mild hepatocellular dysfunction. No evidence of cumulative toxicity was observed. Our experience indicates that interferon alpha-2b is active in patients with advanced cutaneous MM.

Adult↗
PubMed1991

Lysine and protein metabolism in the young lactating woman.

Five lactating and five postpartum non-lactating women of similar ages, times postpartum, body weight and height consumed a liquid formula diet that supplied 1.3 g protein and 32 kcal/kg per day (lactating subjects) and 1.1 g protein and 26 kcal/kg per day (non-lactating subjects). Their last meal supplied 25% of the daily intake and was consumed 4 h before they received L-[13C1]lysine (27 mumol/kg) by a single intravenous injection and L-[15N2]lysine (27 mumol/kg) orally. Frequent plasma and breath samples were collected for 6 h during which time they consumed no food. On a separate day, subjects received NaH13CO3 (10 mumol/kg) as a single intravenous dose and breath samples were collected for 6 h. Plasma tracer lysine levels were determined by gas chromatography-mass spectrometry isotope ratiometry, and breath 13CO2 levels were measured by gas-isotope-ratio mass spectrometry. Averaged tracer data for the two groups were fitted to a multicompartmental model of lysine and protein metabolism that partitioned lysine kinetics between a central and two tissue compartments. The tissue compartments had characteristically fast and slow rates of lysine turnover. The results were compared with those previously obtained in nulliparous women. The postpartum state was associated with a reduction in protein turnover in a compartment with a rapid rate of protein turnover and postpartum women catabolized significantly less lysine than nulliparous controls. Lactating women catabolized slightly more lysine than the non-lactating postpartum subjects, especially when lysine catabolism was expressed as a proportion of lysine flux. Lactation was associated with smaller splanchnic and extracellular pools of free lysine and with an increase in the rate constant for absorption of orally administered lysine. Lysine flux was significantly lower in the lactating subjects and this was associated with a decrease in the rate of lysine turnover in the slowly turning over lysine compartment. The results suggest that lactation is associated with a slower rate of protein turnover in a peripheral tissue compartment. We conclude that an intake of 1.3 g protein/kg per day may be inadequate to support the protein needs of lactation and body protein metabolism and may result in metabolic adaptations that maintain lactation at the potential expense of other aspects of maternal protein turnover.

Adult↗
PubMed1990

Dermoid cyst in the mouth: value of ultrasound.

Teratomas including dermoid cysts occur in approximately 1:4000 births with the incidence in the head and neck varying according to different authors between 1.6 and 6.9 per cent. The case presented is of a 28-year-old Caucasian male in whom a dermoid cyst occurred in the floor of the mouth where ultrasound was found useful in the pre-operative assessment. The role of ultrasound in the pre-operative management of lesions in the head and neck is discussed.

Adult↗
PubMed1989

Factitious illness and the ENT surgeon.

Factitious illness' is a recently classified group of diseases characterized by repeated purposeful simulation of physical or mental illness in order to obtain medical or psychiatric treatment. 'Münchausen Syndrome' is a classical example of this group. The case reported is a 26-year-old Caucasian male who presented with recurrent facial swelling between December 1978 and November 1987. His true condition eluded diagnosis for so long because he presented repeatedly with overt clinical signs which appeared severe enough to justify the symptoms claimed.

Adult↗
PubMed1989

Incorporation of deuterium-labeled fatty acids into human milk, plasma, and lipoprotein phospholipids and cholesteryl esters.

Fatty acid metabolism and the contribution of dietary fatty acids to milk cholesteryl ester (CE) and phospholipid (PL) were investigated in normal lactating mothers. The approach used was to feed mixtures of triglycerides containing deuterium-labeled palmitic acid (16:0-2H2), oleic acid (18:1-2H6), and linoleic acid (18:2-2H4). Milk and plasma samples were collected for 72 hr. Triglyceride (TG), CE, and PL fractions from milk, plasma, and lipoprotein were isolated and analyzed by gas-liquid chromatography and mass spectrometry. Data for the milk CE and PL fractions showed a definite selectivity for incorporation of 16:0-2H2 and 18:1-2H6 relative to 18:2-2H4. Based on the ratios of the deuterated fatty acids incorporated into the milk CE and PL samples, their incorporation times and isotopic enrichment data, it appears that these fatty acids are supplied mainly by the TG derived from chylomicrons and very low density lipoproteins. Plasma and lipoprotein CE data showed a progressive increase in 18:2-2H4 content, with 16:0-2H2 and 18:1-2H4 remaining relatively constant over the collection period. Plasma and lipoprotein PL data showed a higher rate for incorporation of 18:2-2H4 than 16:0-2H2 and 18:1-2H6 over the course of the sampling period. Comparison to previous data from adult males indicates lactation does not have a major effect on the general metabolism of these fatty acids. An increase with time in the isotopic enrichment of 18:2-2H4 in the plasma and lipoprotein CE and PL samples was observed which is consistent with in vitro selectivities reported for lecithin:cholesterol acyltransferase and phosphatidylcholine acyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol Esters↗
PubMed1988

Role of recombinant interferon alpha 2 and cimetidine in patients with advanced malignant melanoma.

Following recent reports suggesting that the addition of cimetidine to interferon may enhance response rates in patients with metastatic malignant melanoma, we have completed a Phase II study of the use of recombinant alpha 2 interferon and cimetidine in patients with advanced malignant melanoma and who had progressive disease following interferon therapy alone. We observed two partial responses, no complete responses, and two patients had stable disease. Toxicity encountered was analogous to that of interferon alone. We conclude that the additional of cimetidine to alpha interferon is not beneficial in the treatment of advanced metastatic malignant melanoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Infused and ingested labeled lysines: appearance in human-milk proteins.

Incorporation of two labeled forms of lysine into human-milk proteins was studied in fasted lactating subjects to determine whether highly labeled proteins could be produced for subsequent nutritional studies and whether the kinetics of milk synthesis could be studied in humans with stable isotope techniques. Five subjects, maintained on formula diets, received L-[13C1]lysine (27 mumol/kg) as an IV bolus and L-[15N2]lysine (27 mumol/kg) as an oral bolus 4 h postprandially. Milk samples were collected at 30, 45, 90, 150, 240, and 360 min. Tracer lysine levels in the hydrolysate of unfractionated milk protein were determined by gas chromatography-mass spectrometry isotope ratiometry. After a delay of at least 45 min, significant labeling of milk protein was detected and reached a maximum at 150 min with cumulative percent does recovery over 6 h of 0.5%. Human-milk proteins can be labeled for nutritional investigations and in vivo kinetics of milk protein synthesis can be studied with stable isotope techniques.

Administration, Oral↗
PubMed1988

Psychiatric diagnoses in patients with psychogenic dizziness or severe tinnitus.

Psychiatric assessments were made of patients with psychogenic dizziness (N = 17) and severe tinnitus (N = 24) using the Structured Clinical Interview for DSM-III-R (SCID). The psychogenic dizziness group had a high prevalence of psychiatric disorders (100%), the majority being anxiety disorders (94%), particularly diagnoses in the panic-agoraphobic cluster (76%). The severe tinnitus group had a lower prevalence of psychiatric disorders (63%) with a predominance of mood disorders (46%). Those tinnitus patients with no hearing loss tended to have more diagnoses per patient and more anxiety disorders than those with hearing loss. Although this was not a random sampling of these patients populations, the results are of sufficient magnitude to warrant further studies. The implications of the results are discussed in terms of treatment and future research.

Adult↗
PubMed1988

Malignant melanoma--profile of an epidemic.

Cutaneous malignant melanoma is occurring in epidemic proportions in the United States. To provide a profile of persons at risk and the epidemiologic features of malignant melanoma, we reviewed the records of 325 patients with cutaneous malignant melanoma seen at the University of Colorado Health Sciences Center between 1973 and 1983. Most patients had fair skin, brown or blonde hair, blue or green eyes, and had difficulty in suntanning. The majority of melanomas (72%) developed in preexisting nevi. In women, melanomas were most common on the extremities, and in men they occurred most frequently on the trunk, head or neck. The most frequently noted depth of invasion was Clark's level IV. At diagnosis, most of the patients (77%) were at stage I. We conclude that malignant melanoma constitutes a major disease problem in the western United States that is largely preventable with appropriate physician and patient education.

Adolescent↗