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Biomedical subjects

B K Agrawal

Publications and source records attributed to B K Agrawal.

At least 19 recordsLinked to original sources
PubMed2005

Structural and vibrational properties of small carbon clusters.

An ab-initio comprehensive study of the stability and structural and vibrational properties of small carbon clusters, CN for N = 1-10, has been made. We use a self-consistent pseudopotential method within density functional theory in the generalized gradient approximation considering spin polarization. The estimated values of binding energies for the various clusters are overestimated in the non-spin-polarized calculations. On the other hand, for the spin-polarized case, the computed binding energies are in very good agreement with the available experimental data. Also, the calculated vibrational frequencies for CN, N = 2-5, are in reasonable agreement with the available experimental values.

Binding Sites↗
PubMed2005

Ab-initio study of the structural and electronic properties of very thin silver nanowires.

An ab initio study of the energetics, structural, and electronic properties of thin silver nanowires of Ag(n) with n = 1 to 6 has been made in density functional theory in local density approximation. The present study reveals that all of the wires are stable except the wire with 3 silver atoms per unit cell. The linear chain is comparatively less stable. The binding energies of the most stable wires lie in the range 2.60-3.18 eV/atom with maximum values for the 5-Ag pentagonal and the two 6-Ag (hexagonal and pyramidal) nanowires. The nearest neighbor Ag-Ag separations in all of the most stable wires up to n=6 is quite the same and is equal to 2.634 +/- 0.03 A. For the most stable 6-Ag pyramidal wire, the bond length increases to 2.75 or 2.81 A. The cross-sectional dimension of these wires are around 5.0 A. All of the studied silver wires are metallic. A majority of the sd mixed states cross the Fermi level. The density of state is maximum for the 5-Ag pentagonal and 6-Ag pyramidal nanowires, and so is the number of channels (5 or 6) crossing the E(F) which would be available for high electrical conduction.

Algorithms↗
PubMed1997

Triple-drug therapy of Helicobacter pylori infection in duodenal ulcer disease.

OBJECTIVE: To evaluate the efficacy of triple-drug therapy for Helicobacter pylori infection and the effect of its eradication on relapse of ulcer in patients with duodenal ulcer (DU) disease. METHODS: Patients with uncomplicated DU who were H. pylori-positive on urease test or histology were given triple-drug therapy (metronidazole, tetracycline, colloidal bismuth subcitrate). Ulcer healing and H. pylori status were assessed one month after completion of therapy. Those with healed ulcers were followed up endoscopically for ulcer recurrence at 3-month intervals for one year or more. RESULTS: Fifty seven of 60 consecutive DU patients (95%) who were H. pylori-positive were taken up for the study; 46 patients (36 men; median age 40 years, range 13-70) completed the study. Thirty one of them (67%) eradicated H. pylori and had healed ulcers at one month post therapy; of 15 patients with persistent H. pylori infection, ulcers healed in 12 (p = ns). After an average follow up of 11 months, 8 of 12 H. pylori-positive patients had relapse of DU compared to 5 of 31 (16%) H. pylori-negative patients (p < 0.01). CONCLUSIONS: Triple-drug therapy was effective and safe for H. pylori infection, the lower rate of eradication observed compared to results elsewhere probably being related to bacterial resistance. Eradication of H. pylori was associated with healing of ulcers, resolution of antral gastritis and a significant fall in the rate of ulcer relapse.

Adult↗
PubMed1993

End point for sclerosis of esophageal varices.

BACKGROUND: Small esophageal varices are difficult to inject intravariceally and complete eradication of varices may not be therapeutically necessary. METHODS: A prospective study designed to compare the use of different end points of sclerotherapy ie (i) total eradication (grade 0) (ii) grade I varices or (iii) grade II white (IIw) varices, by stopping variceal injection when one of these was reached. The patients were followed endoscopically and clinically at 3-4 mo intervals. OUTCOME MEASURES: Variceal recurrence and rebleeding rates. RESULTS: Of 266 patients with portal hypertension (147 cirrhosis, 51 non-cirrhotic portal fibrosis, 68 extra-hepatic portal venous obstruction), 232 (87.2%) reached one of the three end points--six to grade 0, 96 to grade I and 130 to grade IIw. Among 212 patients followed up for a mean post-sclerotherapy period of 12.2 mo (range 3-48 mo), variceal recurrence rates, time intervals to recurrence and rebleed rates were comparable in patients with endpoints of grade I and grade II (white) varices (28.5% vs 38.9%, 10.8 mo vs 9.2 mo, and 7.7% vs 7.8%, respectively; all p = ns). Overall, 51 patients had interval bleed before reaching the end point--50 (98%) of them bled from grade III and IV varices while only one patient (2%) bled with grade IIw varices. CONCLUSION: Grade I or grade IIw varices should be acceptable as the end points for endoscopic sclerotherapy of esophageal varices.

Adult↗
PubMed1993

Combination of anticholinergic agent and H2 receptor antagonist in duodenal ulcer treatment--a randomized, double blind multicenter study.

BACKGROUND: The acid suppressive abilities of H2 receptor antagonists and anticholinergics have been claimed to be additive. METHODS: A multicenter, double-blind, randomized trial comparing ranitidine (150 mg) plus propantheline bromide 15 mg at bedtime to ranitidine 300 mg alone at bedtime was conducted in 161 patients with endoscopically confirmed uncomplicated duodenal ulcer. RESULTS: After six weeks of therapy, ulcer healing rates in the two groups were comparable ie 80% in the combination group (ranitidine + propantheline) and 79.4% in the ranitidine group. Pain relief after one, two and four weeks of treatment was also comparable in the two groups. Side effects to drugs were minor and comparable in both the groups. CONCLUSION: A combination of 150 mg ranitidine and 15 mg propantheline bromide is as efficacious as 300 mg ranitidine in inducing healing of uncomplicated duodenal ulcers, with similar side-effects but at greatly reduced cost.

Adult↗
PubMed1991

Upper gastrointestinal mucosal lesions in chronic renal failure.

The upper gastrointestinal mucosa was studied endoscopically in 182 patients (140 males, 42 females) with chronic renal failure prior to hemodialysis. Endoscopy revealed normal mucosa in 77 patients (42.3%), inflammatory mucosal lesions in 88 (48.4%), peptic ulcer in 16 (8.8%; duodenal 15, gastric 1) and Barrett's ulcer in one patient. Upper gastrointestinal bleeding was noted at presentation in 16 (8.8%) cases and was associated with erosive gastritis, duodenitis and duodenal ulcer in 11, 3 and 2 patients respectively. Thus patients with chronic renal failure had a high prevalence of inflammatory mucosal changes.

Adolescent↗
PubMed1991

Cerebrospinal fluid N-acetyl neuraminic acid estimation for early diagnosis and differentiation of bacterial meningitis.

Cerebrospinal fluid (CSF) analysis for free, bound and total N-Acetyl Neuraminic Acid (NANA) as well as serum NANA was done in 68 patients of bacterial meningitis, of which 37 cases were of pyrogenic meningitis and 31 of tuberculous meningitis. Ten patients were included in the control group. The free NANA levels were increased in only pyogenic meningitis, independent of protein levels but the bound form increased with the increase in CSF proteins. The increase of free NANA in CSF of pyogenic meningitis patients was not related to the cell count or sugar content in CSF or to the duration or severity of illness. This finding can be of great help in differentiating cases of pyogenic meningitis, particularly partially treated patients, who may have ambiguous pictures of CSF analysis, from the cases of tuberculous meningitis.

Bacterial Infections↗
PubMed1990

A comparative therapeutic trial of sucralfate and ranitidine in initial healing and relapse rate of duodenal ulcer.

The present study was carried out to examine the comparative efficacy of sucralfate and ranitidine in the treatment of duodenal ulcer. Sixty-six patients with endoscopically diagnosed duodenal ulcer were studied in a 4-6 weeks randomised, single blind trial comparing sucralfate 1 gm T.D.S. one hour before meal and 1 gm nocte (34 pts) with ranitidine 300 mg nocte (32 pts). Six patients (four on sucralfate and 2 on ranitidine) failed to complete the study. Endoscopy after four weeks of treatment showed an ulcer healing rate of 57% in the sucralfate group compared with 73% in ranitidine group (p greater than 0.1). At six weeks these figures had risen to 87% and 90% respectively (p less than 0.5). After one year followup study 69% of sucralfate treated ulcers relapsed whereas the relapse rate was 82% in ranitidine treated ulcer group (p less than 0.1). It was observed that the relapse was earlier in the ranitidine group as compared to sucralfate group (p less than 0.01 at 3 months and p less than 0.05 at 6 months). Asymptomatic recurrence was seen in 15% (6/40) patients. Sucralfate was not only as effective as ranitidine in short term healing of duod. ulcer but also delayed the relapse of ulcer in long term followup after initial healing with the drug.

Acute Disease↗
PubMed1989

Post sclerotherapy esophageal ulcers: a prospective analysis of their behaviour.

The reported incidence of post sclerotherapy esophageal ulcers has shown marked variation, possibly due to lack of uniform criteria for their diagnosis. Using fixed criteria (size greater than or equal to 5 mm, duration greater than or equal to 2 weeks), we prospectively studied 82 patients with portal hypertension, who underwent four or more sessions of endoscopic sclerotherapy (EST), for the occurrence and behaviour of these ulcers. Post sclerotherapy ulcers occurred after 43 (9.2%) of 465 EST sessions in 30 (36.6%) of 82 patients. Ulcers were significantly associated with two complications: rebleed during the course of sclerotherapy (33% of ulcers bled compared to 3% from variceal rupture; p less than 0.001) and esophageal stricture formation (66.7% of strictures occurred in patients who had ulcers; p less than 0.05). Ulcers occurred more frequently in patients with poor liver function (61.5% in Child's C grade compared with 31.9% in Child's A or B grades; p less than 0.05) and after injection into larger varices (83.7% in varices grades 3 and 4, 16.3% in lower grades; p less than 0.005). Severe persistent chest pain (p less than 0.001) and pyrexia (p less than 0.01) after sclerotherapy were clinical pointers of ulcerogenesis.

Adult↗
PubMed1983

Gastroscopic cytology and biopsies in diagnosis of gastric malignancies.

The outcome in gastric malignancy has changed in recent years owing to its early and accurate diagnosis employing fiber-optic endoscopy and histocytology. One hundred and two subjects with endoscopic demonstration of various gastric lesions were subjected for brush cytology and multiple biopsies. Observing a high degree of specificity, the accuracy of brush cytology was 81% and histology 72% with cumulative diagnostic yield of 91%. There was no false-positive report with cytology; histology, however, gave three false-positive results. The present study thus confirms the high diagnostic accuracy of brush cytology combined with multiple biopsies in gastric malignancies.

Adult↗
PubMedDate not supplied

A study of metopic sutures in human skulls.

The present study has been carried out in fifty-one adult human skulls for metopic sutures in the department of anatomy, Nepalgunj Medical College, Chisapani. Metopic sutures were found in six skulls (11.46%) This study showed higher incidences of incomplete metopic sutures (7.84%). One skull showed double incomplete sutures (one to right of bregma and other in the middle of the frontal bone in the mid line), which was of, a very rare variety seen in frontal bone of (1.96%), three skulls showed incomplete sutures (3.92%). Though the number of the skulls was small, the study showed a rare morphological variety, which was well correlated with earlier workers.

Adult↗