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Biomedical subjects

R Pandey

Publications and source records attributed to R Pandey.

At least 73 records · Page 4Linked to original sources
PubMed1996

Evaluation of clinical and histological prognostic markers in drug-induced acute interstitial nephritis.

We analyzed the case records of 19 patients diagnosed to have drug-induced acute interstitial nephritis to assess the clinical profile and role of steroids in renal recovery, and to correlate histological features to outcome. Patients with underlying glomerular diseases, malignancy, obstructive nephropathy, or systemic infections were excluded. Nonsteroidal anti-inflammatory drugs alone accounted for 6 cases (group A), whereas antibiotics were the major offender in the remaining patients (group B). In 13/19 (69%) cases, renal failure was severe enough to require dialytic support. Overall 14/19 (74%) of the patients recovered normal renal function within 6 weeks of withdrawal of the offending drugs. Neither the extent of renal recovery nor the time required for it was altered by oral steroids. Tubular atrophy and interstitial fibrosis adversely affected renal recovery. Oliguria, tubular necrosis, interstitial edema, and the density/distribution of interstitial infiltrate did not have any effect on the rate/extent of renal recovery.

Acute Disease↗
PubMed1996

Bisphosphonate inhibition of bone resorption induced by particulate biomaterial-associated macrophages.

Aseptic loosening of total joint replacements is associated with bone resorption. A heavy infiltrate of foreign body macrophages in response to biomaterial wear particles is commonly found in the fibrous membrane surrounding loose components. It has recently been shown that foreign body macrophages can differentiate into osteoclastic cells. To determine whether pharmacological inhibitors of bone resorption have a role to play in controlling the osteolysis of aseptic loosening, we analyzed the effect of a bisphosphonate, disodium ethane-1, 1-diphosphonate (EHDP) on this process. Murine monocytes and foreign body macrophages (derived from granulomas formed by subcutaneous implantation of particles of prosthetic biomaterials) were co-cultured with UMR106 osteoblast-like cells in the presence of 1,25 dihydroxyvitamin D3 for 14 days on glass coverslips and bone slices. EHDP significantly inhibited bone resorption in these co-cultures. There was little or no expression of the osteoclast-associated enzyme, tartrate-resistant acid phosphatase (TRAP) in EHDP-treated co-cultures. Addition of EHDP to monocyte-UMR106 co-cultures after the appearance of TRAP-positive cells did not abolish bone resorption, indicating that EHDP, in addition to its known inhibitory effect on osteoclast function, suppresses differentiation of osteoclast precursors. EHDP inhibition of the osteolysis induced by particulate biomaterial-associated macrophages shows that pharmacological inhibition of bone resorption might be used to control the osteolysis of aseptic loosening.

Animals↗
PubMed1996

Healing of chronic antral gastritis: effect of sucralfate and colloidal bismuth subcitrate.

BACKGROUND: Colloidal bismuth subcitrate (CBS) causes endoscopic and histological improvement in gastritis and eradication of Helicobacter pylori in patients with non-ulcer dyspepsia (NUD). The effect of sucralfate, a cytoprotective drug, on endoscopic and histologic gastritis and H pylori clearance is not clear. We studied the effect of CBS and sucralfate on these features in patients with NUD. METHODS: Sixty three patients with NUD and H pylori infection were randomized to receive one of the following for four weeks: (i) CBS (240 mg twice daily) (Group 1); (ii) placebo I, similar in size, color and shape to CBS (Group 2); (iii) sucralfate (2.0 g twice daily) (Group 3) and (iv) placebo II, similar to sucralfate (Group 4). Symptoms, endoscopic and histological findings and H pylori status were assessed before and after treatment. RESULTS: Similar symptomatic improvement was observed with each treatment, indicating a placebo effect. Significant endoscopic and histological improvement was observed with CBS only. CBS was better than sucralfate in inducing endoscopic and histological improvement. Clearance rate of H pylori was 46.6% with CBS, 16.6% with its placebo, 33.3% with sucralfate and 13.3% with its placebo. CONCLUSION: CBS is more effective than sucralfate in inducing endoscopic and histologic healing of H pylori-related gastritis among NUD patients.

Adult↗
PubMed1996

Immunoproliferative small intestinal disease: a frequently missed diagnosis.

Immunoproliferative small intestinal disease (IPSID) is a poorly recognized cause of malabsorption syndrome in India. Clinicopathological features of five patients with IPSID seen over a two-year period are described. Our data suggest that IPSID is commonly misdiagnosed as intestinal tuberculosis due to lack of awareness and reluctance to obtain small bowel biopsies. Empirical institution of anti-tubercular chemotherapy not only leads to delayed diagnosis but also possibly alters the natural history of the disease, resulting in an intermediate phase of amelioration followed by a terminal phase of lymphomatous transformation. The disease is therefore usually diagnosed at an advanced stage and hence is associated with a relatively poor outcome.

Adult↗
PubMed1996

Endoscopic, histologic and microbiologic evaluation of upper abdominal pain with special reference to Helicobacter pylori infection.

OBJECTIVE: To study children with significant upper abdominal pain of unidentifiable etiology and evaluate: (a) the relationship of pain to inflammatory esophago-gastro-duodenal lesions and Helicobacter pylori (HP) infection, and (b) the response to specific therapy. DESIGN: Prospective study. SETTING: Pediatric section of a tertiary referral gastroenterology center. SUBJECTS: Thirty three consecutive children with significant upper abdominal pain [mean age 9.9 +/- 2.7, range 4-15 years; 20 males] were subjected to upper gastrointestinal tract endoscopy and antral mucosal biopsies obtained for rapid urease test (RUT), Gram's staining of impression/crush smears and culture for HP and histologic examination. Patients with HP gastritis were treated with triple therapy, colloidal bismuth subcitrate, amoxycillin and metronidazole, for two weeks. At 8 weeks from the initiation of therapy, patients were re-evaluated for symptoms and HP eradication by repeat endoscopy and antral biopsies. Patients with esophagitis, gastritis and duodenitis without HP infection were treated with ranitidine for 6 weeks. All the patients were followed up for 6 months. RESULTS: Histology revealed antral gastritis in 28/33 (85%) patients. HP infection was present in 12/28 (43%) patients with antral gastritis. Symptomatic improvement with triple therapy was observed in 10/12 (83%) patients with HP gastritis and eradication of HP in 5/7. Improvement on ranitidine therapy was observed in 12/16 (75%) patients with HP negative gastritis. On follow-up, no patient with initial improvement with therapy had relapse of symptoms. CONCLUSION: Symptomatic children with HP related gastritis should be treated with triple therapy and HP negative gastritis with H2-receptor antagonist.

Abdominal Pain↗
PubMed1995

Feline leukemia virus variants in experimentally induced thymic lymphosarcomas.

This study was initiated to evaluate the in vivo infectivity and pathogenicity of a group of recombinant feline leukemia viruses (rFeLVs) previously generated by in vitro forced recombination between a FeLV subgroup A virus (FeLV-A) and an endogenous FeLV (enFeLV) envelope (env) element (Sheets et al., 1992, Virology 190, 849-855). To determine infectivity of rFeLVs, neonatal cats were inoculated with rFeLVs alone or in combination with FeLV-A. The recombinant viruses were able to replicate efficiently in vivo only when administered along with FeLV-A. Of six co-infected cats, three developed thymic lymphosarcomas, one severe aplastic anemia, and two cachexia and depression; all were viremic and seroconverted shortly after inoculation. While both virus types were detected in virtually all tissues examined from these tumor-bearing cats, there was a particularly noteworthy sequence reversion in the rFeLVs. It is known that exogenous FeLV isolates carry a conserved neutralizing MGPNL epitope in the middle of the surface glycoprotein domain of the env gene. In contrast, the parental recombinant viruses used to inoculate these cats harbored the enFeLV-derived MGPNP sequence at this position. However, all in vivo-propagated recombinants displayed the MGPNL sequence, while the env-encoded backbone flanking the MGPNL sequence was that of the parental recombinant virus. These results suggest that viruses with the MGPNL epitope have an in vivo proliferative advantage. The data also provide an explanation for the conservation of this epitope in exogenous FeLVs despite the existence of variant forms in enFeLV proviral elements with which they can recombine.

Amino Acid Sequence↗
PubMed1995

Asp 46 can substitute Asp 96 as the Schiff base proton donor in bacteriorhodopsin.

Bacteriorhodopsin functions as a light-driven proton pump in the purple membrane of Halobacterium salinarium. A variety of studies have established that a proton is transferred over an approximately 10 A distance from Asp 96 to the retinylidene Schiff base during the M --> N transition of the bR photocycle. In order to further explore the mechanism of this Schiff base reprotonation, we compared the properties of the double mutant Thr 46 --> Asp/Asp 96 --> Asn (T46D/D96N), the single mutants Asp 96 --> Asn (D96N) and Thr 46 --> Asp (T46D), and wild-type bR. In contrast to D96N, which exhibits a very slow M decay, T46D/D96N has an M decay close to that of wild-type bR. FTIR difference spectroscopy detects bands in the carboxyl and carboxylate stretch region of T46D/D96N consistent with the deprotonation of Asp 46 during the M --> N transition. In addition, bands associated with structural changes of Asn 96 in the mutant D96N are absent in T46D/D96N. Resonance Raman spectroscopy provides evidence that both T46D/D96N and T46D have a long-lived N-like species in their photocycles. These data demonstrate that Asp 46 can substitute for Asp 96 as the proton donor group in the reprotonation pathway of the Schiff base during the M --> N transition. However, N decay is delayed in comparison to wild-type bR. This may be due to a partial block in the proton pathway leading from the cytoplasmic medium to Asp 46.

Asparagine↗
PubMed1995

Behavior of N-acylated daunorubicins in MDR1 gene transfected and parental cells.

The substrate specificity of the P-glycoprotein (P-170), a multidrug transporter, was studied using N-acylated daunorubicin derivatives and four MDR1 cDNA transfected cell lines. Results showed that N-acetyl-daunorubicin is a substrate, but the longer fatty acid derivatives, N-octanoyl and N-dodecanoyl daunorubicins, are not. This conclusion was reached by flow cytometric drug uptake assay, cell proliferation assays, and confocal microscopy. It was concluded that the longer fatty acid derivatives interact with plasma membranes in a way that affected P-glycoprotein function.

3T3 Cells↗
PubMed1995

Cystic intracranial mass lesions: possible role of in vivo MR spectroscopy in its differential diagnosis.

Thirty-four patients showing cystic intracranial mass lesions on MR imaging were evaluated by in vivo proton MR spectroscopy (MRS) with the aim of detecting lesion-specific spectral patterns that may assist imaging in better tissue characterization. In vivo spectroscopy was performed using stimulated echo acquisition mode with echo times 20 and 270 m in all, and spin echo with echo time 135 m in 11 patients. All primary neoplasms (intra-as well as extra-axial) showed choline (3.22 ppm) resonance along with lipid and/or lactate (1.3 ppm). It was not possible to grade cystic gliomas based on N-acetyl asparate-to-choline ratio. High-grade gliomas (n = 8) showed lipid/lactate and low-grade gliomas (n = 6) showed only lactate. Seven patients with brain abscess showed resonances only from acetate (1.92 ppm), lactate (1.3 ppm) and alanine (1.5 ppm). Two cases of metastatic adenocarcinoma showed only lipid/lactate. In 7 patients with epidermoid cyst, lactate along with an unassigned resonance at 1.8 ppm was observed and could be easily differentiated from arachnoid cysts (n = 2), which showed only minimal lactate. A case of cystic meningioma could be differentiated from cystic schwannoma by the presence of alanine in the former. It is concluded that MR imaging, when combined with in vivo MRS, may help to better characterize intracranial cystic mass lesions.

Brain↗
PubMed1995

Asymmetry in emotional face: its role in intensity of expression.

Normal subjects rated expressiveness of two posed facial emotions, happy and sad; the photographs were stratified in terms of intensity of expression and were prepared in composite (right-right, left-left), normal, and mirror-reversed facial orientations. The left side of the face was more expressive for intermediate intensity expressions of happiness and for least intense expressions of happiness and sadness. The right side of the face was more expressive for most intense expressions of happiness and sadness.

Adult↗
PubMed1995

Non-islet cell tumour induced hypoglycaemia with acromegaloid facial and acral swelling.

The syndrome of non-islet cell tumour hypoglycaemia (NICTH) has been linked with the synthesis and secretion of 'big' IGF-II. We report a patient with a large pelvic clear cell sarcoma who developed recurrent severe hypoglycaemia and in addition presented with severe soft tissue facial swelling, skin tags and nuchal hyperpigmentation. After resection of the tumour serum 'big' IGF-II returned to normal and the acromegaloid skin changes remitted.

Acromegaly↗
PubMed1995

Characterization of intracranial mass lesions with in vivo proton MR spectroscopy.

PURPOSE: To assess the use of in vivo proton MR spectroscopy for characterization of intracranial mass lesions and to ascertain its reliability in grading of gliomas. METHODS: One hundred twenty patients with intracranial masses were subjected to volume selective spectroscopy using stimulated echo acquisition mode (echo time, 20 and 270 milliseconds) and spin echo (echo time, 135 milliseconds) sequences. The intracranial lesions were grouped into intraaxial and extraaxial, as judged with MR imaging. Assignment of resonances was confirmed in two samples each of brain abscess, epidermoid cyst, and tuberculoma using ex vivo high-resolution MR spectroscopy. RESULTS: The in vivo spectra appeared distinct compared with normal brain in all the cases. All high-grade gliomas (n = 37) showed high choline and low or absent N-acetyl-L-aspartate and creatine along with lipid and/or lactate, whereas low-grade gliomas (n = 23) were characterized by low N-acetyl-aspartate and creatine and high choline and presence of only lactate. N-acetyl-aspartate/choline ratio was significantly lower and choline/creatine ratio was significantly higher in high-grade gliomas than in low-grade gliomas. Presence of lipids suggested a higher grade of malignancy. All metastases (n = 7) showed lipid and lactate, whereas choline was visible in only four cases. Epidermoids showed resonances from lactate and an unassigned resonance at 1.8 ppm. Meningiomas could be differentiated from schwannomas by the presence of alanine in the former. Among the infective masses, pyogenic abscesses (n = 6) showed resonances only from cytosolic amino acids, lactate, alanine, and acetate; and tuberculomas (n = 11) showed only lipid resonances. CONCLUSIONS: In vivo proton MR spectroscopy, helps in tissue characterization of intracranial mass lesions. Spectroscopy is a reliable technique for grading of gliomas when N-acetyl-aspartate/choline and choline/creatine ratios and presence of lipids are used in combination.

Adolescent↗
PubMed1995

Diagnosis of infection by frozen section during revision arthroplasty.

We assessed the efficacy of intraoperative frozen-section histology in detecting infection in failed arthroplasties in 106 hips and knees. We found inflammatory changes consistent with infection (an average of one or more neutrophil polymorphs or plasma cells per high-power field in several samples) in 18 cases; there was a significant growth on bacterial culture in 20 cases. Compared with the bacterial cultures, the frozen sections provided two false-negative results and three false-positive results (sensitivity, 90%; specificity, 96%; and accuracy, 95%). The positive predictive value was 88%, the negative value, 98%. These results support the inclusion of intra-operative frozen-section histology in any protocol for revision arthroplasty for loose components.

Adult↗