Biomedical subjects
M R Thomas
Publications and source records attributed to M R Thomas.
The tracheostomal washer: a simple aid for tracheo-oesophageal speakers with a large tracheostome.
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Left ventricle filling abnormalities prior to and following treatment of thyrotoxicosis--is diastolic dysfunction implicated in thyrotoxic cardiomyopathy?
Despite cardiac failure being a well recognised complication of thyrotoxicosis, systolic function has generally been reported as maintained or enhanced. In this study, left ventricular diastolic function was assessed in 16 thyrotoxic patients and 18 age-matched controls by pulsed-Doppler echocardiography. Patients were re-studied after 3 and 12 months of treatment. Prior to treatment all standard Doppler-derived indices of diastolic function were significantly different to control (isovolumic relaxation time (IVRT) 63 +/- 18.9 vs 84.0 +/- 14.8 ms, peak early filling velocity (Emax) 79.2 +/- 15.2 vs 61.9 +/- 10.7 cm.s-1, peak atrial filling velocity (Amax) 68.2 +/- 17.9 vs 42.2 +/- 9.4 cm.s-1, deceleration of early filling (E/F slope) 6.1 +/- 1.8 vs 3.7 +/- 1.1 m.s-1, thyrotoxic vs control). However, these filling abnormalities appear likely to reflect the tachycardia and reduced systemic vascular resistance (SVR) found in the patients (heart rate 102 +/- 15 vs 76 +/- 9, SVR 874 +/- 207 vs 1293 +/- 362 dynes.s-1 x cm-5, both P < 0.001). After 3 months of treatment haemodynamics were similar in the two groups but filling remained abnormal in patients with a pattern suggesting increased transmitral pressure gradients (Emax 73.1 +/- 15.1 cm.s-1, Amax 55.8 +/- 19.2 cm.s-1, E/F slope 4.9 +/- 2.0 m.s-1, all P < 0.05 compared to controls).(ABSTRACT TRUNCATED AT 250 WORDS)
Echocardiographic restenosis after successful balloon dilatation of the mitral valve with the Inoue balloon: experience of a United Kingdom centre.
OBJECTIVES: (a) To assess the echocardiographic incidence of restenosis after successful balloon dilatation of the mitral valve at a mid-term follow up of one year among a population of predominantly United Kingdom patients. (b) To identify any factors, assessed before or during dilatation, which may predict the development of restenosis. DESIGN: Successful dilatation of the mitral valve was defined as an increase in mitral valve area of > 25% and a final valve area of at least 1.5 cm2. Echocardiographic restenosis was defined at follow up as a loss of 50% of initial gain and a valve area of less than 1.5 cm2. Mitral valve area was assessed by transthoracic echocardiography before, during, 48 hours after, and one year after successful balloon dilatation of the mitral valve. Echo score before dilatation (an assessment of valvar and subvalvar calcification, thickening, and mobility), age, rhythm, echocardiographic mitral valve area before and after dilatation, left atrial pressure before and after dilatation, and end diastolic mitral valve gradient before and after dilatation were compared in those patients with and without echocardiographic restenosis at one year. SETTING: A regional cardiothoracic centre in the United Kingdom that performs 20-30 balloon dilatations of mitral valves each year. PATIENTS: 39 patients, with symptomatic dominant mitral stenosis, who had undergone successful balloon dilatation of the mitral valve, and in whom echocardiographic assessment of mitral valve area was available at one year. 92% of patients were citizens of the United Kingdom. INTERVENTIONS: Balloon dilatation of the mitral valve by the Inoue technique. MAIN OUTCOME MEASURES: Mitral valve area and patient symptom class (New York Heart Association) one year after successful dilatation of the mitral valve. RESULTS: The incidence of echocardiographic restenosis was eight of 39 patients (21%). Of the eight patients with restenosis four underwent mitral valve replacement, two had repeat dilatation of the mitral valve, and two remained on medical treatment. With univariant analysis, factors associated with restenosis were increased age, higher echo score before dilatation, and a lower mitral valve area immediately after the operation. The only independent risk factor for restenosis, shown by multivariant analysis, was a high echo score before dilatation. There was no significant fall in mitral valve area at one year in those patients without restenosis. Most (28/31) of these patients had echocardiographic evidence of splitting of at least one commissure after dilatation compared with only two of eight patients who developed restenosis. Of 10 patients with an echo score before dilatation > or = 10 only two had an initially successful operation and no restenosis at one year. CONCLUSIONS: The echocardiographic incidence of restenosis after dilatation of the mitral valve by the Inoue technique in patients of the United Kingdom is 21%. The principal factor associated with restenosis is a high echo score before dilatation. Increases in mitral valve area are maintained in those patients without restenosis and it is likely that the mechanism of initial increase in valve area is different in the two groups, being commissural splitting in those patients who do not get restenosis and valve stretching in those that do. In patients with an echo score > or = 10 dilatation of the mitral valve should be considered only as a palliative procedure.
Endocrine and cardiac paracrine actions of insulin-like growth factor-I (IGF-I) during thyroid dysfunction in the rat: is IGF-I implicated in the mechanism of heart weight/body weight change during abnormal thyroid function?
Thyroid hormones are essential for the normal growth and development of many tissues. In the rat, hypothyroidism is associated with growth impairment, and hyperthyroidism with the development of a hypercatabolic state and skeletal muscle wasting but, paradoxically, cardiac hypertrophy. The mechanism by which thyroid hormone produces cardiac hypertrophy and myosin isoenzyme changes remains unclear. The role of IGF-I, an anabolic hormone with both paracrine and endocrine actions, in producing cardiac hypertrophy was investigated during this study in hyperthyroid, hypothyroid and control rats. A treated hypothyroid group was also included in order to assess the effect of acute normalization of thyroid function. Body weight was significantly lower in the hyperthyroid (mean +/- S.E.M.; 535.5 +/- 24.9 g, P < 0.05), hypothyroid (245.3 +/- 9.8 g, P < 0.001) and treated hypothyroid (265.3 +/- 9.8 g, P < 0.001) animals when compared with controls (618.5 +/- 28.6 g). Heart weight/body weight ratios were, however, significantly increased in the hyperthyroid (2.74 +/- 0.11 x 10(-3), P < 0.01) and treated hypothyroid (2.87 +/- 0.07 x 10(-3), P < 0.001) animals when compared with controls (2.26 +/- 0.03 x 10(-3). Serum IGF-I concentrations were similar in the control and hyperthyroid rats (0.91 +/- 0.07 vs 0.78 +/- 0.04 U/ml, P = 0.26), but bioactivity was reduced by 70% in hyperthyroid serum, suggesting a circulating inhibitor of IGF. Serum IGF-I levels (0.12 +/- 0.03 U/ml, P < 0.001) and bioactivity (0.12 +/- 0.04 U/ml, P < 0.001) were significantly lower in the hypothyroid group. Liver IGF-I mRNA levels were not statistically different in the control and hyperthyroid animals, but were significantly reduced in the hypothyroid animals (P < 0.05 vs control). Heart IGF-I mRNA levels were similar in the control and hypothyroid rats, but were significantly increased in the hyperthyroid and treated hypothyroid animals (increased by 32% in hyperthyroidism, P < 0.05; increased by 57% in treated hypothyroidism, P < 0.01). Cardiac IGF-I was significantly elevated in hyperthyroidism (0.16 +/- 0.01 U/mg heart tissue, P < 0.01), was low in hypothyroidism (0.08 +/- 0.01 U/mg, P < 0.01) and was normalized in the treated hypothyroid group (0.11 +/- 0.01 U/mg vs control, 0.13 +/- 0.01 U/mg). Low body mass during both hypothyroidism and hyperthyroidism is therefore associated with reduced systemic IGF bioactivity. In hypothyroidism there is a primary defect in the endocrine function of IGF-I, while in hyperthyroidism serum IGF bioactivity is reduced in the presence of normal endocrine production of this anabolic hormone.(ABSTRACT TRUNCATED AT 400 WORDS)
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)
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.
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.
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.
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.
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.
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.
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.
Polymyositis presenting with dyspnoea, greatly raised muscle enzymes, but no apparent muscular weakness.
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Tuberculosis presenting as jaundice.
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'Use of electronic devices'.
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Acute right ventricular infarction.
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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.