Candidate screening of blast resistance donors for rice breeding

Rice blast is one of the most serious diseases in the world. The use of resistant cultivars is the most preferred means to control this disease. Resistance often breaks down due to emergence of new races; hence identification of novel resistance donors is indispensable. In this study, a panel of 80 released varieties from National Rice Research Institute, Cuttack was genotyped with 36 molecular markers that were linked to 36 different blast resistance genes, to investigate the varietal genetic diversity and molecular marker-trait association with blast resistance. The polymorphism information content of 36 loci varied from 0.11 to 0.37 with an average of 0.34. The cluster analysis and population structure categorized the 80 National Rice Research Institute released varieties (NRVs) into three major genetic groups. The principal co-ordinate analysis displays the distribution of resistant and moderately resistant NRVs into different groups. Analysis of molecular variance result demonstrated maximum (97%) diversity within populations and minimum (3%) diversity between populations. Among tested markers, two markers (RM7364 and pi21_79-3) corresponding tothe blast resistance genes (Pi56(t) and pi21) were significantly associated and explained a phenotypic variance of 4.9 to 5.1% with the blast resistance. These associated genes could be introgressed through marker-assisted to develop durable blast resistant rice varieties. The selected resistant NRVs could be good donors for the blast resistance in rice crop improvement research.

Percutaneous transluminal angioplasty using a cutting balloon for stenosis of the arch vessels in aortoarteritis.

Percutaneous transluminal angioplasty with or without stenting of steno-occlusions in the supra-aortic arch vessels in aortoarteritis is associated with suboptimal results and higher restenosis rates, particularly in those with diffuse disease. We report two cases of stand-alone cutting balloon angioplasty for patients who presented with critical stenosis of the common carotid artery, and occlusion of the subclavian artery, respectively.

Carotid artery stenting with filter protection.

BACKGROUND: Neurologic events associated with distal embolization of debris during percutaneous carotid artery stenting complicate the procedure. Filter devices for cerebral protection potentially reduce the risk of embolization and other neurologic events. We studied the feasibility, safety, and efficacy of carotid artery stenting with a filter device. METHODS AND RESULTS: Between January 2002 and January 2003, a total of 22 consecutive patients (30 lesions) who had >70% diameter stenosis of the internal carotid artery underwent carotid artery stenting with filter protection at our institute. The mean age of the patients was 64+/-9 years; 14 were men and 8 women, and 15 had neurologic symptoms. A stent was successfully implanted in 29 lesions. It was possible to position a filter device in all the 29 lesions. Neurologic complications during the procedure, in the hospital, and at 30-day clinical follow-up occurred in 2 patients. One patient suffered a minor stroke that resolved within 24 hours. None of the patients had a major embolic stroke. There was one death from intracerebral hemorrhage related to hyperperfusion and the use of a glycoprotein IIb/IIIa inhibitor. CONCLUSIONS: Filter protection during carotid artery stenting seems technically feasible, safe, and effective. In the present study, the incidence of embolic neurologic events was low.

Renal artery involvement in patients of coronary artery disease undergoing coronary angiography--a prospective study.

METHODS: We prospectively studied the angiographic incidence of renal artery stenosis in 1000 consecutive patients who underwent coronary angiography for clinically suspected coronary artery disease since December, 1998. Selective renal arteriography was performed in all the patients (mean age 57 years, 74.6% males) after coronary angiography. RESULTS: Systemic arterial hypertension was present in 52%, 29.1% were smokers, 21% had diabetes and 31.2% had hypercholesterolemia. Significant coronary artery diseases was found in 849 (84.9%) patients. Of the total patient cohort, 103 (10.3%) patients had renal artery disease; 78 (7.8%) had insignificant stenosis (> 50%) and significant renal artery stenosis (< 50%) was identified in 25 (2.5%) patients. Three had bilateral renal artery stenosis. Comparisons were made between renal artery stenosis and risk factor profile. There was no statistically significant association between renal artery stenosis and parameters like diabetes mellitus, hypertension, smoking, lipid levels and serum creatinine. CONCLUSION: In our study, the absolute number of cases with significant renal artery stenosis is small, so no statistical analysis could be performed to demonstrate the relationship of presence of renal artery stenosis with severity of CAD. However patients with severe coronary artery disease or having multiple risk factor showed a trend towards increased prevalence of renal artery stenosis, hence renal angiography should be done for this subset of patients.

Carotid artery involvement in patients of atherosclerotic coronary artery disease undergoing coronary artery bypass grafting.

BACKGROUND: Patients with concomitant critical carotid and coronary artery disease are at risk of major neurological events while undergoing coronary artery bypass grafting. The presence of carotid artery stenosis increases the stroke rate in the perioperative period. In an effort to reduce the stroke rate, many institutions perform routine preoperative noninvasive assessment of the carotid arteries. METHODS AND RESULTS: We analyzed the clinical and laboratory data of 1,200 patients who underwent coronary artery bypass surgery in the last 2 years. Carotid Doppler was normal in 186 patients (15.5%), and showed <30% stenosis in 796 (66.3%), 30%-50% in 110 (9.2%), 50%-70% stenosis in 64 (5.3%) and critical (>70%) stenosis in 44 (3.7%) patients. Conventional risk factors such as hypercholesterolemia, hypertension, smoking and family history were not independent predictors of carotid artery stenosis. However, diabetes as a risk factor had a significant association with carotid artery disease (79.6% v. 43.8%, p<0.02). There was a trend towards increased prevalence of carotid artery stenosis in patients with > or = 2 risk factors (84.3% v. 68.8%). Patients with significant carotid artery stenosis had severe coronary artery disease (triple-vessel disease 93.3%, left main coronary artery disease 12.0%). Out of 44 patients with critical carotid artery stenosis, 27 were subjected to carotid angiography. Doppler findings correlated well with angiography. Seventeen patients underwent carotid artery intervention. None had any perioperative neurological events. A total of 5 (0.4%) patients had a major stroke. Coronary artery bypass grafting was done in 27 patients with critical stenosis without any intervention. The stroke rate (11.1%) was higher in these patients compared to patients with < 70% carotid artery disease or post-carotid intervention (2.5%) patients. Thus, untreated >70% carotid artery stenosis was associated with a higher stroke rate. CONCLUSIONS: Doppler screening of the carotid artery is helpful in detecting the subgroup of patients at increased risk of stroke. Patients with critical carotid artery stenosis should be subjected to angiography. Prophylactic intervention may reduce the occurrence of stroke in the perioperative period.

Percutaneous transluminal myocardial revascularisation: current status and future perspectives.

Percutaneous transluminal myocardial revascularisation presently appears to be a potential palliative treatment for coronary artery disease, neither controlled with drugs nor amenable to available coronary revascularisation techniques. Ongoing trials will provide answer to short and long term efficacy. Recent developments using angiogenic growth factors appear very promising, and the role of growth factors as an adjunct to percutaneous transmyocardial revascularisation with laser remains to be seen.

Coronary stenting without pre-dilatation: an observational study.

Conventional coronary stenting is done after pre-dilatation of the lesion. The bleeding complications and incidence of subacute stent thrombosis have been reduced significantly by the use of antiplatelet agents and high pressure balloon inflation to ensure complete stent expansion. Elective stenting also can be done without pre-dilatation by "stent alone technique." This approach significantly reduces the procedural cost and ischaemia time, avoiding potential complications such as abrupt vessel closure because of extensive dissection after conventional angioplasty and prior to stent deployment. Eighty patients of stable angina pectoris suitable for coronary angioplasty underwent stenting without pre-dilatation. Out of the 100 stents used, 38 were hand-crimped and 62 were pre-mounted. The target vessels were left anterior descending artery in 56 percent, right coronary artery in 32 percent and left circumflex in 12 percent. The procedure was successful in 88 percent lesions. In 12 percent stenting could be done only after pre-dilatation. In all these, there was proximal tortuosity and calcification. The fluoroscopy time was 10.2 +/- 4.5 minutes. The average number of balloons used per lesion was 1.08. Stent embolisation occurred in only one patient. There were no major adverse cardiac events in any of the patients. Thus stenting without pre-dilatation is safe. Patients who are eligible for stenting without pre-dilatation are those with stable angina pectoris without fluoroscopically visible calcium or coronary artery tortuosity and with lesions of moderate complexity.

Elective coronary artery stenting--immediate and follow up results.

Elective coronary artery stenting was performed in 242 consecutive patients in our centre for complex lesions (Type B, C), proximal lesions, restenotic lesions, total occlusion and venous grafts. The procedural success rate was 94.21%. Three patients (1.23%) required emergency coronary artery bypass surgery. Acute and sub-acute thrombosis rate was 1.26% and 4.13%, respectively. There was one in-hospital death (0.41%). 164 patients were followed up clinically for a mean period of 11 +/- 6 months (range 1 month to 30 months). Angiographic follow up was done in 68 patients with a restenosis rate of 16.17%.

Severity of mitral regurgitation in mitral valve prolapse syndrome. A Doppler echocardiographic study.

Thirty-three consecutive patients with mitral valve prolapse with a systolic murmur were evaluated using pulsed doppler echocardiography to quantify the severity of mitral regurgitation. There were thirteen (39%) patients with mild regurgitation, twelve patients (36%) with moderate regurgitation and eight patients (24%) with severe regurgitation. It was noticed that, all the patients with severe regurgitation had posterior leaflet prolapse. In contrast, patients with anterior leaflet prolapse had either mild or moderate regurgitation only. Our results suggest that the degree of mitral regurgitation differs depending on the leaflet that shows the prolapse, which may be of importance in the followup of patients with mitral valve prolapse.

Electrocardiographic left atrial enlargement--correlation with echo.

To assess the utility of electrocardiogram in identifying left atrial enlargement, electrocardiogram of 600 consecutive patients were correlated with their M-mode echocardiographic findings. Left atrial enlargement, as reflected by P terminal force in V1 had sensitivity of 79%, specificity 91%, predictive value 85% and accuracy of 86%. Patients older than 30 years with large left atrium (greater than 5.0 cm) had atrial fibrillation more frequently than younger patients (P less than 0.001). It is concluded that P terminal force in V1 is a reliable indicator of left atrial enlargement.

Low dose metoprolol in acute myocardial infarction.

A study of the effects of low dose Metoprolol was undertaken in 37 patients with acute myocardial infarction. These patients were randomly divided into three groups depending on the dose of the drug per kg body weight. Group I, consisting of 18 patients, received 0.36 to 0.65 mg per kg per day, Group II (10 patients) received 0.66 to 0.99 mg/kg/day, and Group III (9 patients) 1 to 1.81 mg/kg/day. To assess the degree of beta blockade achieved, the parameters that were evaluated were the fall in blood pressure and heart rate. There was a fall in systolic blood pressure which ranged from 7 to 17%, and fall in heart rate of 6.6 to 12.8% in the 3 groups over the 48-hour study period. These observations were compared with the results obtained from the Goteberg Metoprolol trial and Metoprolol in acute myocardial infarction (MIAMI) trials wherein 200 mg of Metoprolol per day were used. Our preliminary observations suggest that Indian patients may not need such a high dose, and Metoprolol at 50-100 mg per day would probably be sufficient to get the desired effect.

Relapsing polychondritis--a case report and review of literature.

A case of relapsing polychondritis with aortic aneurysm is presented and relevant literature reviewed. Only one case of relapsing polychondritis has been previously reported in Indian literature. Increased awareness of this relatively rare, multi-system disease is warranted, to facilitate the diagnosis.