Biomedical subjects
Publications and source records attributed to P Ramachandran.
Paraduodenal hernia is a rare cause of intestinal obstruction. It occurs typically in adults, but can also present in children. The symptoms include chronic abdominal pain and acute intestinal obstruction. Rapid evaluation must be followed by early surgery to avoid the morbidity and mortality associated with strangulation.
Citrus tristeza virus (CTV) is an aphid-transmitted closterovirus, which causes one of the most important citrus diseases worldwide. Isolates of CTV differ widely in their biological properties. CTV-infected samples were collected from four locations in India: Bangalore (CTV-B), Delhi (CTV-D), Nagpur (CTV-N), and Pune (CTV-P), and were maintained by grafting into Kagzi lime ( Citrus aurantifolia (Christm. Swing.). All isolates produced typical vein clearing and flecking symptoms 6-8 weeks after grafting. In addition, CTV-B and CTV-P isolates produced stem-pitting symptoms after 8-10 months. The CTV coat protein gene (CPG) was amplified by RT-PCR using CPG specific primers, yielding an amplicon of 672 bp for all the isolates. Sequence analysis of the CPG amplicon of all the four Indian isolates showed 93-94% nucleotide sequence homology to the Californian CTV severe stem pitting isolate SY568 and 92-93% homology to the Japanese seedling yellows isolate NUagA and Israeli VT p346 isolates. In phylogenetic tree analysis, Indian CTV isolates appeared far different from other isolates as they formed a separate branch. Comparison among the Indian isolates was carried out by restriction analysis and restriction fragment length polymorphism (RFLP). Specific primers to various genome segments of well-characterized CTV isolates were used to further classify the Indian CTV isolates.
OBJECTIVE: To study clinical profile, risk factors and pattern of coronary artery involvement in females. MATERIAL AND METHOD: Female patients undergoing coronary angiography at Apollo Hospitals, Chennai during 1996-1998 for angina were analysed for risk factors. RESULTS: Out of 5997 angiograms, 660 (11%) were females of which 574 (88%) post-menopausal. 48% had atypical chest pain, 11% had unstable angina, 1% had acute myocardial infarction (MI). Past history of MI was present in 48%. Risks factors were hypertension in 60%, diabetes in 52%, obesity in 41%, dyslipidemia in 32%, family history in 36%. 71% patients used oral contraceptive. None of the patients were smoker, 34.8% pre-menopausal and 72.2% post-menopausal had coronary artery disease. Single vessel disease 33% vs 22.1% two vessel disease 43.3 vs 31.2%. Triple vessel 22.3 vs 46.6% and diffuse disease 10% vs 38.7% was seen in pre-menopausal vs post-menopausal females, respectively. CONCLUSIONS: Family history was the predominant risk factor in pre-menopausal and diabetes mellitus and hypertension in post-menopausal females. Diffuse and triple vessel disease were significantly common in post-menopausal females.
Circadian variations in the incidence of hypertension and coronary events are well known with early morning surges. Effect of lunar cycles on various medical illnesses like seizures and psychiatric disturbances are documented. However, the effect of lunar cycles on coronary events has been sparsely documented. The authors studied the incidence of acute coronary events and admission patterns in the departments of emergency medicine and cardiology. Inclusion criteria included unstable angina, non-ST elevation myocardial infarction (MI) and ST elevation MI. Exclusion criteria included chest pain syndromes which were subsequently deemed non-cardiac by invasive or non-invasive investigations. Data from 1999 to 2001 were analysed. Admissions on full moon days were compared with those on new moon days. There were 30 full moon days and 30 new moon days and 223 admissions on full moon days and 266 on new moon days. This difference was statistically significant [p = .005]. Sixty-seven per cent were males and the rest were females. Subgroup analysis of mortality, postinfarction angina, effect on diabetics and hypertensives were done which showed an increased trend in new moon days. It is concluded that there is increased incidence of acute coronary events associated with new moon days.
Pulmonary embolism and deep venous thrombosis account for hundreds of thousands of hospitalisation and afflict millions of individuals worldwide. A brief overview on the subject concerned is presented here.
Marfan's syndrome is an autosomal dominant disorder with risk of premature death from rupture of an aneurysm or aortic dissection. A case of acute severe aortic regurgitation due to flail aortic valve in a patient with family history of Marfan's syndrome which may be a form fruste of this syndrome is reported.
The authors describe skin biopsy findings in patients with peripheral neuropathy associated with diabetes and impaired glucose tolerance (IGT). Six patients with IGT, eight with early diabetes-associated neuropathy, and five controls were recruited. Most subjects underwent nerve conduction studies (NCS) and quantitative sensory tests (QST). Skin biopsy was abnormal in all neuropathy subjects and correlated poorly with NCS. Neuropathy associated with IGT primarily affects small fibers and is similar to early diabetes-associated neuropathy.
Giant cell myocarditis is an unusual and frequently fatal form of myocarditis. A 37-year-old woman presented with resistant cardiac failure and left ventricular aneurysm. She underwent Dor's endoaneurymorrhaphy and was histopathologically proved to have giant cell myocarditis. She had significant improvement of symptoms and was alive 13 months after surgery. Dor's endoaneurysmorrhaphy may be a useful therapeutic modality in selected cases of giant cell myocarditis.
OBJECTIVE: Surgery has been the only therapeutic option in patients with hypertrophic obstructive cardiomyopathy (HOCM) who are resistant to standard treatment. Percutaneous transluminal septal myocardial ablation (PTSMA) by alcohol-induced occlusion of the septal artery for the reduction of left ventricular outflow tract (LVOT) gradient is a novel method. However, long-term clinical follow-up is insufficient. This study reports the acute and mid-term results after PTSMA in symptomatic patients with HOCM. METHODS: Six patients (4 men and 2 women) with symptomatic HOCM and inadequate response to pharmacologic therapy had their major septal branches ablated with alcohol. Mean duration of follow-up was 1.5 years. RESULTS: There was reduction in LVOT gradient in all patients (100%) with a mean reduction of 50 mmHg. Two patients developed complete heart block (CHB) and 3 patients developed bifascicular block. CHB persisted in 1 patient. Two patients died within 8 days of the procedure; one due to cerebrovascular accident and 1 due to asystole. The patient who died of asystole had CHB but refused permanent pacemaker implantation. CHB reverted in 1 patient and bifascicular blocks persisted in 3 patients. Clinical and echocardiographic follow-up was achieved in the 4 surviving patients after 1.5 years. All surviving patients had LVOT gradient reduction and clinical improvement. CONCLUSION: PTSMA for HOCM is a non-surgical technique for reducing LVOT gradient. Heart blocks are one potential complication, and may require pacemaker implantation. Long-term follow-up and a larger series of patients are required to determine conclusive therapeutic significance.
Primary angioplasty (PTCA) in acute myocardial infarction has many theoretical advantages including better antegrade flow and reduced intracranial haemorrhage. However the improvement in the mortality and morbidity of primary angioplasty in the randomized trials from sophisticated centres has not been translated to the community setting. Primary PTCA is a suitable alternative to thrombolytic therapy if performed in a timely fashion by persons skilled in the procedure in a suitable laboratory. It is also recommended in patients with cardiogenic shock and in those with contraindications to thrombolytic therapy. Combination of thrombolytics and glycoprotein IIb/IIIa inhibitors with primary angioplasty may form the reperfusion strategy of the future.
Myocardial viability assessment is crucial in the evaluation of patients who had prior myocardial infarction for revascularisation procedures. Conventional methods include nuclear myocardial perfusion imaging, dobutamine stress echocardiography and positron emission tomography. Utility of nitrate in assessment of viability was assessed. Twenty-five patients with prior myocardial infarction underwent 99mTc-sestamibi single photon emission computed tomography protocol of stress, rest and post 5 mg sublingual isorbide dinitrate. The mean age of the patients was 51.28 years. Eight (32%) had reduction in perfusion defect and increased tracer uptake following nitrate administration. It is concluded that addition of nitrate adds to utility of conventional perfusion imaging in the assessment of myocardial viability.
Congenital malformations of the lung are rare and vary widely in their presentation and severity. The authors reviewed 25 years of experience with specific reference to diagnosis, treatment, and outcome. From July 1970 to June 1995, 70 patients were diagnosed with congenital malformations of the lung, which included sequestration (n = 20), foregut anomalies (n = 20), congenital lobar emphysema (CLE; n = 10), congenital cystic adenomatoid malformation (CCAM; n = 5), benign lung cysts (n = 6), lung aplasia/ hypoplasia (n = 4), and other miscellaneous disorders (n = 5). All patients with pulmonary hypoplasia presented at birth. With the exception of one patient, infants with CCAM and CLE presented before 5 months of age. All other patients presented from birth to 16 years of age. A prenatal diagnosis was accurate in two patients. Although prompt surgical management is the rule, the exceptions were children with bilateral lung involvement. Corrective surgery was delayed in some patients in whom extended respiratory support was required or in whom the delay led to an increase in pulmonary reserve. Extracorporeal membrane oxygenation (ECMO) was used in two patients pre- and postoperatively to manage persistent pulmonary hypertension. This review, representing the largest series of congenital lung lesions, showed that (1) prenatal diagnosis is useful but generally does not change the outcome; (2) computerized tomography (CT) is the optimum postnatal diagnostic imaging modality if chest radiography is not definitive; (3) ECMO can be an adjunct in treating associated pulmonary hypertension; (4) pulmonary resection (lobectomy) is the surgical procedure of choice for most lesions; (5) expected survival is good; and (6) pulmonary hypertension is the most common cause of mortality.
The genotoxic environmental contaminant 1-nitropyrene is metabolised in mammalian systems by pathways more complex than the straightforward nitroreduction which accounts for most of its biological activity in bacteria. In order to evaluate the role of O-acetyltransferase (OAT) activity in generation of genotoxic intermediates from 1-nitropyrene, the mutagenicity of the major primary oxidised metabolites of 1-nitropyrene was characterised in the Ames Salmonella typhimurium plate incorporation assay with strain TA98, and with variants of TA98 deficient (TA98/1,8-DNP6) or enhanced (YG1024) in O-acetyltransferase. 1-Nitropyren-3-ol was more mutagenic in the absence than in the presence of S9, while 1-nitropyren-4-ol, 1-nitropyren-6-ol and 1-nitropyren-8-ol required S9 for maximum expression of mutagenicity. 1-Nitropyren-4-ol (176 rev/nmol without S9, 467 rev/nmol with S9 in TA98) and 1-nitropyren-6-ol (13 rev/nmol without S9, 266 rev/nmol with S9 in TA98) were overall the most potent nitropyrenol isomers assayed. 1-Acetamidopyren-8-ol and 1-acetamidopyrene 4,5-quinone were only minimally active. 1-Acetamidopyren-3-ol exhibited direct-acting mutagenicity. 1-Acetamidopyren-6-ol, previously shown to be a major contributor to mutagenicity in the urines of rats dosed with 1-nitropyrene (Ball et al., 1984b), was confirmed as a potent (359 rev/nmol) S9-dependent mutagen. Both the direct-acting and the S9-dependent mutagenicity of all the compounds studied was enhanced in the OAT-overproducing strain and much diminished (though not always entirely lost) in the OAT-deficient strain, showing that OAT amplifies expression of the genotoxicity of these compounds. 1-Acetamidopyren-6-ol required both S9 and OAT activity in order to exhibit any mutagenicity; this finding strongly implicates N-hydroxylation followed by O-esterification, as opposed to further S9-catalyzed ring oxidation, as a major route of activation for urinary metabolites of 1-nitropyrene.
A method for the assay of mixtures of amprolium and ethopabate in chicken feed was developed utilizing reversed-phase high-performance liquid chromatography (HPLC) after sample clean-up of a methanolic extract by solid-phase extraction using CN cartridges. HPLC was done with benzocaine as internal standard on a C-8 column with methanol-water 40:60, containing octanesulfonic acid, triethylamine and acetic acid, as mobile phase. Eluate was monitored at 274 nm. Baseline separation was achieved with retention times of approximately 7.5, 9.4, and 10.4 min, for amprolium, benzocaine, and ethopabate respectively. Feed constituents did not give peaks after 6.5 min. Peak area ratios were linear over 10-180 ng of amprolium, and 2-18 ng of ethopabate injected. Limits of quantitation at AUFS 0.05 were 0.5 and 0.3 ng respectively. Recovery studies from spiked feed (n = 9), covering +/- 30% of usual doses in feed, gave percent recoveries (+/- SD) of 99.4 +/- 1.4% for amprolium and 100.5 +/- 2.6% for ethopabate. Applying the method to two different batches of commercial feed gave results which were comparable to those obtained by the AOAC spectrofluorometric methods.
This study was designed to evaluate the sensitivity and specificity of abdominal ultrasonography as a diagnostic modality in a large series of children who presented with possible appendicitis. From August 1990 to July 1994, 452 children (203 boys, 249 girls) with an average age of 11 years (range, 1 to 20 years) underwent graded compression ultrasonography of the right lower quadrant of the abdomen for the evaluation of possible appendicitis. In the first 18 months of the study all patients with the possible diagnosis of appendicitis (group I; 180 patients) had abdominal ultrasonography after members of the surgical team evaluated and documented their findings in the medical record. In the second study period (30 months), abdominal ultrasonography was recommended only when the clinical diagnosis of acute appendicitis was equivocal (group II; 272 patients). Abdominal ultrasonography was performed using the graded compression technique with a 5.0-MHz linear array transducer. A positive ultrasound study for appendicitis was defined as the presence of an enlarged noncompressible appendix with an outer wall to outer wall diameter of greater than 6 mm, the presence of a complex mass, or the presence of an appendicolith. The sonographic data were correlated with surgical and pathological findings. Appendicitis was confirmed in 112 of the 452 cases. In 17 of these, the appendix was perforated. In the overall group of 452 children, abdominal ultrasonography had a sensitivity of 90%, specificity of 96%, and accuracy of 95%. There was no significant morbidity in the 11 patients with a false-negative study result. All 11 patients had an uncomplicated appendectomy. There were 11 false-positive results; 10 of these patients had a negative laparotomy result (negative laparatomy rate, 8.9%). For the two groups, the sensitivity and specificity of ultrasonography in the diagnosis of appendicitis were equivalent (group 1: 88% sensitivity, 96% specificity; group 2: 92% sensitivity, 97% specificity). On the basis of the high sensitivity and specificity rates, ultrasonography of the appendix can be a useful adjunct to standard examination in the diagnosis of acute appendicitis.
Abdominal pain is a common complaint in adolescents, and its evaluation is challenging. This article provides a method of evaluating the adolescent with acute abdominal pain, reviews the more common causes that may lead to surgical intervention, and provides algorithms for determining a specific diagnosis and mode of treatment.
Vasectomy acceptance has been declining in India during the past 20 years. Even if the risk of prostate cancer is marginally higher in vasectomized men, this risk in India has to be assessed against the immediate safety and other possible long-term benefits of this procedure. The Indian Council of Medical Research has launched a case-control study, which is unlikely to be time-consuming or beyond the available means and resources, in order to obtain definitive data on this problem. Meanwhile, vasectomy remains an excellent procedure for the couple seeking permanent methods of contraception, and specific efforts to promote its acceptance must continue in India.
Breastfeeding has been considered the best mode of feeding the infant. In traditional countries like India, it has been the tradition among poor income groups of women and the universal adage breast feed as long as possible goes uncontested. However, the appropriate age at which supplementation should start is replete with controversy and varies between as early as 3-6 months. While the debate on when should supplementation be started continues, it is also important to know if the nutritional benefit is expressed in terms of growth of the infant, under the existing unhygienic conditions. This study was therefore undertaken.