Inorganic- Organic Hybrid Materials For Photonics

Molecular materials comprised of inorganic:organic composites are of considerable interest in photonics, optoelectronics and biophotonics. We report broad band lasing and tunable filters in sol-gel processed poly (p-phenylene vinylene) PPV: Silica composites. Optical power limiting in near IR wavelength region is also reported in dye doped PPV: silica multiphasic nanocomposites. For making hybrid inorganic: organic composites the reverse micelle mediated synthesis technique has been exploited to synthesize dye encapsulated metal oxide particles, thiocresol capped CdS clusters, Cul and AgI nanoparticles. These particles were dispersed in polymeric matrix for applications in photoconductivity and photorefractive measurements.

Coronary collaterals by transthoracic echocardiography in coronary artery disease

Demonstration of coronary collaterals has been mostly done by coronary angiographic techniques. Coronary collaterals have been demonstrated by transthoracic echocardiography for patients with anomalous origin of coronary arteries from pulmonary artery. Indirect assessment of collaterals to an infarct-related artery has been done using myocardial contrast echocardiography. We describe in this article 3 patients with coronary artery disease in whom coronary collaterals were demonstrated by transthoracic echocardiography before angiography. To our knowledge, coronary collateral demonstration by transthoracic echocardiography before angiography in patients with coronary artery disease has not been previously reported.

Prevalence of risk factors for coronary atherosclerosis in a cross-sectional population of Andhra Pradesh

BACKGROUND

The prevalence of risk factors for atherosclerosis is increasing in India due to changing socioeconomic factors and lifestyles. Data for the state of Andhra Pradesh are scanty in this regard.

METHODS AND RESULTS

The prevalence of conventional risk factors for atherosclerosis was prospectively assessed in a unique sample of 3307 workers of a political party drawn from all over the state of Andhra Pradesh. Demographic, anthropometric, clinical and laboratory data were collected prospectively over a period of 6 months. The mean age of the subjects was 43.12+/-9.5 years, 2955 (88%) were males and 385 (12%) females. The prevalence of risk factors was as follows: diabetes in 810 (24%); hypertension in 924 (28%); lipid abnormality in 1908 (58%); smoking in 805 (24%) and positive family history in 555 (17%). Obesity was prevalent in 1178 (36%) of the population. All coronary risk factors, excepting family history, were significantly more prevalent in males [diabetes: 777 (26%) v. 34 (9%), p<0.001; hypertension: 833 (28%) v. 72 (19%), p<0.001; lipid abnormality: 1729 (59%) v. 172 (45%), p<0.001; smoking: 801 (27%) v. 7 (2%), p<0.001; and family history: 497 (17%) v. 60 (16%), p=0.54]. Region-wise analysis showed a high prevalence of diabetes in the Andhra and Rayalaseema regions, hypertension in the Andhra region, and smoking in the Rayalaseema region. Lipid disorders were equally prevalent in all the regions.

CONCLUSIONS

The present report shows a disturbing burden of coronary risk factors in the study population. There is an urgent need to undertake population-based measures to reverse the trend.

A study of clinical efficacy of sildenafil in patients with primary pulmonary hypertension

BACKGROUND

Primary pulmonary hypertension is a disorder with limited treatment options and poor outcome. Sildenafil, a pulmonary vasodilator, is likely to be beneficial in primary pulmonary hypertension. We studied the clinical efficacy of sildenafil in patients with primary pulmonary hypertension.

METHODS AND RESULTS

A registry of patients with primary pulmonary hypertension has been maintained in our hospital since January 1999. Of a total of 60 patients. 29 (M:16, F:13) consented to try sildenafiL. New York Heart Association functional class, six-minute walk test and Doppler echocardiographic evaluation of pulmonary artery pressure was done before and after treatment with sildenafil. Sildenafil was initiated at a dose of 25 mg thrice a day and increased up to 100 mg thrice a day as tolerated. There was a significant improvement in the functional class. The six-minute walked distance increased from 297.07+/-130.69 m at baseline to 427.68+/-85.35 m after 3 months of sildenafil therapy (p<0.0003). The mean of the pulmonary artery systolic pressure before starting sildenaffil was 109.26+/-24.15 mmHg (mean+/-SD) and it decreased to 95.15+/-24.64 mmHg (p<0.008). While 19 of the 31 historical controls in whom sildenafil was not given died during follow-up (11-44 months), only 1 of the 29 patients given sildenafil died (in an accident) during follow-up (5-20 months).

CONCLUSIONS

Sildenafil, a pulmonary vasodilator, has a beneficial effect in patients with primary pulmonary hypertension in improving the functional class, six-minute walked distance and in decreasing the pulmonary artery pressures.

Disability and dementia in the emergency department

The elderly consume medical services in an amount disproportionate to their number. Disability and dementia are commonly underdiagnosed and misunderstood in any emergency department setting. Educating emergency physicians regarding the evaluation of dementia, disability, and abuse is crucial to appropriate management and optimal outcome of these clinical problems.

Solid-State Cavity Lasing from Poly(p-Phenylene Vinylene)-Silica Nanocomposite Bulk

We have fabricated inorganic-organic nanocomposite bulk samples consisting of poly(p-phenylene vinylene) (PPV) and silica by in situ polymerization of a PPV salt monomer within a porous glass using a base-catalyzed polymerization reaction and subsequent heat treatment. The samples processed at temperatures above 200 degrees C showed a sharp reduction in fluorescence. Solid-state cavity lasing was achieved from the samples processed at 150 degrees C with optical efficiency as high as 11.4%. We report characteristic narrowing of the linewidth and the temporal profile.

Clinical evaluation of new balloon mountable coil stent: in-hospital and follow-up results

The purpose of this study was to determine the feasibility, safety and efficacy of elective deployment of a new coil-stent (KR stent) in patients with coronary artery disease. KR stent deployment was attempted in 100 patients (135 lesions) enrolled prospectively at a single centre from December 1996 to March 1997. Ten, 15, 18, 24, and 32 mm long KR stents were manually crimped onto balloons and deployed in native coronary artery lesions. Majority of the patients had recent acute coronary syndromes (unstable angina 30% and post-myocardial infarction angina 56%). Diabetes was present in 34 percent of the patients. Fifty-six percent had single-vessel and 44 percent multi-vessel disease. In 38 percent, the lesions were located in proximal segments and 40 percent of lesions were long. KR stents were successfully deployed in 98 percent of patients. Mean minimal luminal diameter increased by 2.89 +/- 0.63 mm (from 0.57 +/- 0.38 mm before to 3.45 +/- 0.56 mm after the procedure). Mean percent diameter stenosis decreased from 83.33 +/- 10.84 percent before to 3.38 +/- 5.74 percent after the stent deployment. Mean reference vessel diameter was 3.45 +/- 0.56 mm. There were occasional technical complications including balloon rupture (1), stent migration (2) and distal embolisation of atheromatous material (1). One patient developed subacute stent thrombosis. There were no other major in-hospital cardiovascular events. At the end of six-month follow-up, there were no myocardial infarction or death. Six patients presented with recurrence of symptoms within six-months of the procedure, four of whom underwent target vessel revascularisation procedure. In conclusion, the in-hospital and six-month follow-up clinical results were highly encouraging with KR stent. Successful deployment rates were high despite unfavourable clinical and angiographic background. Low clinical events on follow-up will make it suitable for elective stenting.

Thrombolysis in left-sided prosthetic valve occlusion: immediate and follow-up results

Thrombolytic therapy is used increasingly for prosthetic valve thrombosis. Fear of peripheral embolism has limited its use in left-sided valve occlusions. Thirty-eight patients with prosthetic valve occlusion were treated with thrombolytic agents on 44 occasions. Duration of thrombolytic therapy was individualized. Patients were followed up with clinical, echocardiographic, and cine-fluoroscopic evaluation. Average time from onset of symptoms to presentation was 9.7 days. The anticoagulation status was inadequate in 70% of instances. The majority (75%) were in functional class IV, 8 of them being in shock. Overall success was seen in 88.6%: immediate complete success in 18 and partial in 21. Nine of those with partial success had delayed opening of the leaflets. There were nine instances of rethrombosis and one instance of re-rethrombosis; 6 patients received repeat thrombolysis with success in 5. Seventy-six percent (29/38) of the patients were surviving at the time of reporting. In conclusion, the present study demonstrates the feasibility of thrombolytic therapy for left-sided prosthetic valve occlusion. Delayed opening is common in patients with initial partial success. Rethrombosis remains a major problem.

Percutaneous balloon versus surgical closed commissurotomy for mitral stenosis. A prospective, randomized trial

BACKGROUND

We performed a prospective, randomized trial comparing percutaneous balloon commissurotomy with surgical closed commissurotomy in 40 patients with severe rheumatic mitral stenosis.

METHODS AND RESULTS

Data were analyzed by investigators who were masked to treatment assignment or phase of study. Patients randomized to balloon (n = 20) or surgical (n = 20) commissurotomy had severe mitral stenosis without significant baseline differences (left atrial pressure, 26.1 +/- 4.2 versus 27.6 +/- 6.2 mm Hg; mitral valve gradient, 18.0 +/- 4.2 versus 19.7 +/- 6.3 mm Hg; mitral valve area, 1.0 +/- 0.2 versus 1.0 +/- 0.4 cm2, respectively). At 1-week follow-up after balloon commissurotomy, pulmonary wedge pressure was 14.3 +/- 7.2 mm Hg; mitral valve gradient was 9.6 +/- 5.1 mm Hg; and mitral valve area was 1.6 +/- 0.6 cm2 (all p less than 0.0001). At 1-week follow-up after surgical closed commissurotomy, wedge pressure was 13.7 +/- 5.4 mm Hg; mitral valve gradient was 9.4 +/- 4.2 mm Hg (both p less than 0.0001); and mitral valve area was 1.6 +/- 0.7 cm2 (p less than 0.003). At 8-month follow-up, improvement occurred in both groups: Mitral valve area was 1.6 +/- 0.6 cm2 in the balloon commissurotomy group (p less than 0.002) and was 1.8 +/- 0.6 cm2 in the surgical closed commissurotomy group (p less than 0.0001). There was no difference between the groups at 1-week or 8-month follow-up (all p greater than 0.4). One case of severe mitral regurgitation occurred in each group; complications were otherwise related to transseptal catheterization. There was no death, stroke, or myocardial infarction. Cost analysis revealed that balloon commissurotomy may substantially exceed the cost of surgical commissurotomy in developing countries, whereas it may represent a significant savings in industrialized nations.

CONCLUSIONS

We conclude that percutaneous balloon commissurotomy and surgical closed commissurotomy result in comparable hemodynamic improvement that is sustained through 8 months of follow-up.

Increased levels of plasma renin, aldosterone, catecholamines and vasopressin in chronic ambulatory peritoneal dialysis (CAPD) patients

Fluid excess can cause hyporeninemia and hypoaldosteronemia in hemodialysis patients. In six patients on CAPD, plasma renin activity (PRA) and plasma aldosterone (PA) were elevated to levels of : PRA 10.2 +/- 2.9 nl (1-5 ng/ml/h), and PA: 47.4 +/- 16.2 (normal 5-20 ng/dl). In 4 patients, data posthemodialysis and later during CAPD revealed that PRA increased from 0.9 +/- 0.3 to 14.1 +/- 4.6 and PA increased from 3.4 +/- 0.3 to 67.4 +/- 24.9 on CAPD (p less than 0.05). Mean arterial pressure was lower on CAPD and serum glucose was higher. No significant difference was seen in weight, hematocrit, BUN, or potassium, however. Plasma volume was not decreased in five CAPD patients: 3619 +/- 358 ml (predicted 3083 +/- 201 ml). Elevated catecholamine levels were seen in CAPD patients: norepinephrine 868.0 +/- 104.1 (normal 358.4 +/- 41.5 pg/ml), epinephrine 386.3 +/- 49.2 (normal 58.3 +/- 10.6 pg/ml). Plasma vasopressin levels were elevated to the range usually seen with hyperosmolality. In eight patients who lost or gained weight on CAPD, levels of PRA and PA changed as expected, but catecholamine levels did not correlate with weight changes. The data suggest that in CAPD patients, PRA and PA may be elevated in association with augmented sympathetic stimulation and elevated vasopressin levels. Serial observations demonstrated that PRA and PA can respond appropriately to changes in body weight, while catecholamine and vasopressin levels seem to be influenced by other factors.

A preliminary report on gamma-irradiated protein-dye complexes

In spectral studies of gamma-irradiated protein-dye complexes, influences of concentrations of the components and changes in dye character are mainly noted.

Effects of gamma-rays on DNA-cholesterol complex

Effects of gamma-rays on the DNA-cholesterol complex have been studied. Radiation-induced changes are found and compared with those on DNA-dye or drug complexes.