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Biomedical subjects

N K Shrestha

Publications and source records attributed to N K Shrestha.

11 recordsLinked to original sources
PubMed2001

Conversion of ammonia to dinitrogen in wastewater by Nitrosomonas europaea.

Because Nitrosomonas europaea contains ammonia-oxidizing enzyme, nitrite reductase, and nitrous oxide reductase, the conversion of ammonia to dinitrogen was tried with different reaction conditions. In aerobic reaction conditions, ammonium was converted to nitrite (NO2-), while under oxygen-limiting or oxygen-free conditions, NO2(-)-N formed from ammonia oxidation by N. europaea was reduced to N2O and dinitrogen with 22% conversion. During denitrification, optimal pH for the production of N2O and dinitrogen was found to be 7.0-8.0. Dinitrogen was not produced in acidic pH <7.0. A low partial oxygen pressure as well as oxygen-free conditions are favorable for high production of dinitrogen.

Ammonia↗
PubMed1983

Two-dimensional echocardiographic diagnosis of left-atrial thrombus in rheumatic heart disease. A clinicopathologic study.

Two-dimensional echocardiographic studies were performed in 293 patients with rheumatic heart disease who underwent open-heart mitral valve surgery during an 18-month period. Diagnostic confirmation of a left atrial thrombus was based on direct inspection of the left atrium during surgery and histopathologic examination. Two-dimensional echocardiographic recordings were reviewed. Of the 293 patients, 33 had left atrial thrombi by two-dimensional echocardiographic criteria. This diagnosis was confirmed at surgery and histopathologic study in 30 (specificity 98.8%). A thrombus was not found in three patients. In 21 other patients, left atrial thrombi were present but were not detected by two-dimensional echocardiography (sensitivity 58.8%). Ten of these 21 had thrombi in the left atrial cavity. In 11 patients, thrombi were located in the left atrial appendage, all of which were missed by two-dimensional echocardiography. Excluding these 11 left atrial appendage thrombi, the sensitivity of two-dimensional echocardiography for detecting left atrial cavity thrombi was 75.0%.

Adolescent↗
PubMed1978

Left atrial rhythm in man: an experimental study.

Ten patients with atrial septal defect of the secondum variety undergoing diagnostic haemodynamic study were subjected to electrical stimulation of the endocardium of the left atrium using a bipolar pacing electrode catheter. The polarity, frontal plane P wave axis and P wave configuration were analysed from ten scalar 12 lead electrocardiogram (ECG), recorded at 25-50 mm/sec during sinus rhythm and left atrial stimulation. While four patients demonstrated the "dome and dart" appearance of P waves in V1, nine out of ten patients revealed upright P waves in V1 during left atrial pacing; one patient showed inverted P waves in V1-V6. Four patients had negative "P" waves in L1 and only five of ten patients had inverted "P" waves in L1 and V6. All the criteria of left atrial rhythm were present in only one patient. It appears that the "P" waves change during left atrial pacing are variable and that the typical findings of left atrial rhythm are not obtained in all cases. This study was planned because trans-septal left atrial stimulation in the genesis of left atrial rhythm has not been widely reported.

Cardiac Catheterization↗
PubMedDate not supplied

Protease-sparing regimen in a real-life practice with naïve patients: an equal opportunity approach?

PURPOSE: Proven clinical efficacy of protease-sparing regimens (PSR) has been shown. Concerns exist about broad applicability of these regimens in advanced naïve patients. Recent reports have associated a rise in liver enzymes with nevi rapine; however, no data exist with efavirenz. METHOD: 17 consecutive antiretroviral-naïve HIV patients were started on a PSR with efavirenz plus two nucleoside reverse transcriptase inhibitors. Baseline liver enzymes, serum CD38, CD4, and HIV viral load data were collected. Correlation between change in viral load and immune reconstitution on therapy were compared to baseline laboratory values. RESULTS: All patients had a mean viral load decrease of >2 logs, including patients with low initial CD4% or high viral load, and there was no increase of liver enzymes observed at a median follow-up of 42 weeks (range 17-78). There was a perfect correlation between the change in viral load and the initial viral load (p <.0001, r = 1.00) including patients with viral load > or =100,000 copies/mL and CD4 count< or =50 (n = 5). Even patients with low initial CD4 had a significant percentage increase in CD4 count (p <.0002, r = 0.7880). CD38% showed a positive correlation with change in viral load (p =.046, r = 0.522). CONCLUSION: All patients experienced a mean viral load decrease of >2 logs (88% less than 400 copies/mL and 35% less than 20 copies/mL). There were no observed increases in liver enzymes. Patients with low CD4 counts, high initial viral load, or high CD38 expression still experienced a significant change in viral load.

Adult↗