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Biomedical subjects

M Nair

Publications and source records attributed to M Nair.

At least 55 records · Page 3Linked to original sources
PubMed1991

Assessment of mitral valvar stenosis by echocardiography: utility of various methods before and after mitral valvotomy.

Cross-sectional and Doppler echocardiography are currently the most important non-invasive tests for the evaluation of mitral stenosis. Recent experience has, however, shown that parameters that are reliable before mitral valvotomy may not be valid after the procedure. We have studied the validity of estimation of the area of the mitral valve by echo-planimetry, by Doppler pressure half time and the transmitral end-diastolic pressure gradient calculated by continuous wave Doppler in 100 patients (aged 10-30 years) before and after balloon mitral valvoplasty (n = 70) or surgical closed mitral valvotomy (n = 30). These patients underwent cardiac catheterisation and echocardiographic studies before, immediately after and 8-12 (9.3 +/- 2.2) weeks following balloon valvoplasty or closed valvotomy. The area as estimated echocardiographically correlated well with that obtained by the Gorlin formula before (r = 0.80), but not immediately after (r = 0.67) or on follow up after mitral valvotomy. There was good correlation between Doppler pressure half time and the area as estimated by the Gorlin formula before (r = 0.89) and on follow up after valvotomy (r = 0.82), but the correlation was not as good in the immediate period after valvotomy (r = 0.60). The end-diastolic pressure gradients obtained by Doppler examination and at cardiac catheterisation correlated well with each other before (r = 0.94), immediately after valvotomy (r = 0.92) and on follow up (r = 0.94). Hence, the reliability of estimation of the area of the mitral valve by echo-planimetry and by Doppler pressure half time varies according to the time at which the examination is performed following commissurotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Left ventricular volumes and function immediately after balloon mitral valvoplasty.

To evaluate acute changes in left ventricular volumes and function immediately after successful percutaneous balloon mitral valvoplasty, twenty young patients with isolated rheumatic mitral stenosis (male 9, female 11, mean age 22 +/- 6 years) were studied. The area of the orifice of the mitral valve following valvoplasty, increased from 0.97 +/- 0.27 cm2 to 2.46 +/- 0.75 cm2 (P less than 0.001). No significant change was observed in left ventricular end-diastolic volumes (117 +/- 27 ml to 119 +/- 29 ml, P greater than 0.10), end-systolic volumes (51 +/- 21 ml to 50 +/- 20 ml, P greater than 0.10), ejection fraction (0.57 +/- 0.10 to 0.58 +/- 0.10, P greater than 0.10) and left ventricular meridian wall stress (68 +/- 20.10(3) dynes/cm2 to 65 +/- 14, P greater than 0.10) immediately after valvoplasty. There was no acute change in heart rate, left ventricular end-diastolic pressure, cardiac index and grade of mitral regurgitation. Patients with depressed left ventricular ejection fraction (less than or equal to 0.55, n = 10) and those with normal ejection fraction (greater than 0.55, n = 10) had similar baseline left ventricular end-diastolic volumes and showed no significant change in volumes and ejection fraction after the procedure, although the former group had a greater orificial area after valvoplasty (P less than 0.05). We conclude that an acute increase in the orifice of the mitral valve in patients with rheumatic mitral stenosis is not associated with any significant change in left ventricular volumes and function.

Adolescent↗
PubMed1990

Segmental analysis of SPECT 99mTc-methoxy isobutyl isonitrile and 201Tl myocardial imaging in ischaemic heart disease.

To study the potential usefulness of 99mTc-methoxy isobutyl isonitrile (99mTc-MIBI) as a substitute for 201Tl in assessing patients with ischaemic heart disease, 24 patients underwent 1 day rest and exercise 99mTc-MIBI single photon emission computerised tomography (SPECT) 1 week after SPECT exercise 201Tl. All patients were catheterized within 1 month after myocardial imaging. In 17 patients, resting first pass radionuclide angiography (FPRNA) was performed with 99mTc-MIBI. The heart to lung ratio for 99mTc-MIBI and 201Tl was calculated both at rest and exercise. The segmental analysis for myocardial perfusion reveals that 87/96 segments (91%) were correctly classified by SPECT 201Tl and 84/96 segments (88%) were correctly classified by 99mTc-MIBI. A significant correlation was present between LVEF measured by 99mTc-MIBI FPRNA and contrast ventriculography (r = 0.85, P less than 0.0001). The heart to lung ratio both at rest and exercise for 99mTc-MIBI is significantly higher than 201Tl (P less than 0.01 and less than 0.001 respectively). We conclude that 99mTc-MIBI is a promising agent for simultaneous evaluation of myocardial perfusion and cardiac function.

Contrast Media↗
PubMed1990

Oral metoprolol therapy in dilated cardiomyopathy: hemodynamic evidence for improved diastolic function accompanying amelioration of symptoms.

Twenty patients with dilated cardiomyopathy (11 males and 9 females) aged from 14 to 54 (37.3 +/- 10.5) years were treated orally with metoprolol (dose 37.5 mg-100 mg/day, mean 91 +/- 18.6 mg/day) after a baseline hemodynamic study. On follow-up, all patients showed improvement in symptomatic status by at least one NYHA class within 2 to 4 weeks of the initiation of therapy. Repeat right heart study and left ventricular angiography (venous digital subtraction angiography) afer 3 to 6 months of treatment in 10 patients showed a fall in the mean pulmonary arterial wedge pressure from 24.4 +/- 9.6 to 12.8 +/- 7.7 mm Hg (P = 0.025), right ventricular end-diastolic pressure from 8.8 +/- 4.7 mm Hg to 4.5 +/- 1.9 mm Hg (P = 0.025) and mean pulmonary arterial pressure from 34.2 +/- 12.4 mm Hg to 25.9 +/- 10.9 mm Hg (P less than 0.01). There was no significant change in the left ventricular ejection fraction (18.7 +/- 1.6% vs. 22 +/- 0.48%, P = NS) or cardiac index (2.2 +/- 0.48 l/m/m2 to 2.12 +/- 0.68 l/m/m2, P = NS). These hemodynamic results indicate that the improvement in symptoms and congestive cardiac failure produced by treatment with metoprolol in patients having dilated cardiomyopathy is related to improvement in diastolic function of the myocardium.

Adolescent↗
PubMed1990

Clinical and prognostic significance of concanavalin-A-induced suppressor cell activity in malignant cervical neoplasia.

Peripheral blood lymphocytes from patients with different stages of cancer of the uterine cervix were analysed for concanavalin-A-induced suppressor cell activity. All cancer patients had high levels of suppressor activity, the increase corresponding to tumour load. Radiotherapy resulted in further increase of suppressor activity. About six months after radiotherapy, patients who remained disease free returned to pretreatment levels of suppressor cell activity and later showed even lewer levels of suppression. On the other hand, patients who developed recurrent disease maintained sustained high levels of suppression and for all stages they always had higher suppressor activity than the patients who remained disease free in the corresponding stage. These results stress the importance of a possible deranged immune system in these patients and also shows the clinical and prognostic significance of the assay.

Female↗
PubMed1989

Percutaneous balloon mitral valvuloplasty in children and young adults with rheumatic mitral stenosis.

Twenty-eight patients with mitral stenosis, 17 females and 11 males, underwent percutaneous balloon mitral valvuloplasty (BMV). The age range was 10 to 30 (mean 17.8 +/- 6.7) years and all were symptomatic (New York Heart Association [NYHA] class III, 12 patients; class IV, 16 patients). BMV was done with a single balloon in 10 patients and double balloon in 16 patients. Following BMV, there was a significant reduction in transmitral end-diastolic pressure gradient from 23.1 +/- 5.8 to 7.6 +/- 4.2 mm Hg (p less than 0.001) and a significant increase in mitral valve area from 1.06 +/- 0.29 to 2.64 +/- 1.35 cm2 (p less than 0.001), along with an increase in cardiac index from 3.40 +/- 1.18 to 4.26 +/- 1.46 L/min/m2 (p less than 0.01). Improvement in symptomatic status by at least one NYHA class was seen in all patients. Mild mitral regurgitation developed in four and moderate mitral regurgitation developed in one patient. Angiographic evidence of atrial septal defect was present in one patient. Follow-up at 8 to 12 weeks in 12 patients has shown sustained hemodynamic improvement. These short-term results indicate that BMV is an effective nonsurgical procedure for the management of patients with rheumatic mitral stenosis.

Adolescent↗
PubMed1989

Problems of duodenogastric reflux in Tc-99m Hexa MIBI planar, tomographic and bull's eye display.

Tc-99m Hexa MIBI (RP-30) is excreted through hepatobiliary pathways. Myocardial imaging with RP-30 is recommended 45-60 minutes after injection. During this waiting period duodenogastric reflux (DGR) is occasionally seen. Fundal activity due to duodenogastrix reflux presents problems in planar, tomographic, and Bull's eye display. The authors recommend in those cases to give the patient a light meal and wait 15-30 minutes more for the gastric activity to empty in the small intestine before starting myocardial imaging.

Coronary Disease↗
PubMed1989

Uptake and kinetics of Tc-99m hexakis 2-methoxy isobutyl isonitrile in benign and malignant lesions in the lungs.

Kinetics of Tc-99m MIBI uptake was studied in 19 patients with lung lesions (6 benign, 13 malignant). Two dynamic studies were acquired after the I.V. injection of 10-15mCi (370-550 MBq); the first was every second for 60 seconds, followed by a second one every minute for 30 minutes. Delayed images were acquired at two and three hours. By assigning regions of interest (ROI) over the lung lesions (TR), contralateral normal lung (NL) and the heart (Ht), time activity curves (TAC) were generated and time to peak activity was calculated as well as the ratios of TR/NL, Ht/TR and Ht/NL. The Ht/NL ratio was also assessed in five patients referred with diagnosis of ischaemic heart disease (IHD) for myocardial imaging. There was a localized increase of Tc-99m MIBI uptake in ten patients with untreated malignant tumours of the lung. No localized uptake was found in one patient with untreated poorly differentiated squamous cell carcinoma, two treated lung cancer and four patients with non-malignant lesions of the lungs. Two patients with fibrosing alveolitis showed diffuse increase lung uptake. In all positive studies peak tumour was reached within the first minute. There was no statistical difference in the ratio of Ht/NL between all groups except in patients with fibrosing alveolitis. There was no significant difference between the ratios TR/NL, Ht/TR and Ht/NL at 5-10 minutes and 25-30 minutes. The ratio of TR/NL at 25-30 minutes was 1.58 +/- 0.36 in the positive cases versus 1 +/- 0.22 in the negative ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Percutaneous transluminal balloon angioplasty of the aorta in patients with aortitis.

Four patients with aortitis and stenotic lesions of the aorta were successfully treated by percutaneous transluminal balloon angioplasty. The peak systolic gradient across the constrictions decreased from 82.5 +/- 35.7 to 37.5 +/- 18.5 mm Hg immediately after dilatation. Repeat angiography in the first three patients performed 2 months later showed a further decrease in the gradient to 13.8 +/- 9.5 mm Hg. There were no complications during or after the procedure, and all the patients have shown remarkable symptomatic relief during the follow-up.

Adolescent↗
PubMed1985

Iron, zinc, copper, manganese and magnesium in malignant lymphomas.

Lymph node and spleen tissues involved in malignant lymphomas were analysed for iron, manganese, copper, zinc and magnesium by atomic absorption spectrophotometry. The levels of iron are found to be significantly lower in the case of Hodgkin's lymphoma compared with non-Hodgkin's lymphoma and normal lymph nodes. However, they are elevated in Hodgkin's lymphoma when compared with the normal value for spleen tissues. Magnesium is significantly higher in lymph nodes of non-Hodgkin's lymphoma compared with Hodgkin's lymphoma and normal values, but is not altered significantly in spleen tissues. The distribution of the other elements examined is not altered significantly in malignant lymphomas. The importance of the in situ levels of these elements to NMR imaging is discussed.

Copper↗
PubMed1984

Antisocial personality--diagnosis or moral judgment?

Antisocial personality is a problem-filled diagnosis. Even when diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM) II manual, it was replete with value laden terminology. DSM III makes repeated criminal behavior central and includes a list of other behaviors that do not always truly imply an antisocial personality. In order to test the possibility that factors other than those listed in the manual may often influence the diagnosis, the prevalence of required characteristics in patients diagnosed antisocial personality was compared with the prevalence of required characteristics in another personality disorder, schizoid personality. The study involved a hospitalized Veteran's Administration (VA) population, employing DSM II criteria, which was used by the VA at that time. The difference was statistically highly significant. Examination of the case histories suggests that dislike of the patients or negative moral judgments about their actions frequently were involved in making a diagnosis of antisocial personality. It is therefore crucial that moral judgments not be disguised as scientific ones, and the meaning of an antisocial personality diagnosis as utilized by clinicians needs to be seriously questioned.

Adolescent↗