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Biomedical subjects

R Pandey

Publications and source records attributed to R Pandey.

At least 37 records · Page 2Linked to original sources

An assessment of the histological criteria used to diagnose infection in hip revision arthroplasty tissues.

AIM: To characterise the number and nature of the inflammatory cells seen in cases of septic or aseptic loosening of hip arthroplasty, and to establish reliable histological criteria to distinguish between these two conditions. METHODS: Histological examination of paraffin sections of periprosthetic tissues (pseudocapsule, femoral and acetabular pseudomembranes) of 523 cases of aseptic loosening and 79 cases of microbiology culture proven septic loosening. The cellular composition of the inflammatory cell infiltrate was determined semiquantitatively. RESULTS: The finding of a 2+ or greater neutrophil polymorph infiltrate (one or more cells per high power field (x400) on average after examination of 10 fields) in arthroplasty tissues correlated strongly with the microbiological diagnosis of septic loosening: diagnostic sensitivity 100%, specificity 97%, accuracy 99%, positive predictive value 92%, negative predictive value 100%. The finding of a 3+ neutrophil polymorph infiltrate (five or more cells on average per high power field) had a diagnostic sensitivity of 72%, specificity 100%, accuracy 98%, positive predictive value 100%, and negative predictive value 97%. In some cases of septic loosening the finding of a heavy lymphocytic and plasma cell infiltrate was of low diagnostic sensitivity. A neutrophil polymorph infiltrate (generally less than one cell per 10 high power fields) was also seen in cases of aseptic loosening. CONCLUSIONS: The presence of 2+ or more (more than one neutrophil polymorph per high power field (x400) on average after examination of at least 10 high power fields) in periprosthetic tissues provides the most sensitive and accurate histopathological criterion for distinguishing between septic and aseptic loosening of hip arthroplasty.

Arthroplasty, Replacement, Hip↗

Pyoderma gangrenosum. A diagnosis not to be missed.

We describe a case of pyoderma gangrenosum which presented with severe wound breakdown after elective hip replacement. The patient was treated successfully with minimal wound debridement and steroids. This diagnosis should always be considered when confronted with an enlarging painful skin lesion which does not grow organisms when cultured and fails to respond to antibiotic therapy, especially if there are similar lesions in other sites. In patients who have a past history of pyoderma gangrenosum, prophylactic steroids may be indicated at the time of surgery or may be required early in the postoperative period.

Aged↗

Recombinant feline leukemia virus (FeLV) variants establish a limited infection with altered cell tropism in specific-pathogen-free cats in the absence of FeLV subgroup A helper virus.

Feline leukemia virus subgroup B (FeLV-B) is commonly associated with feline lymphosarcoma and arises through recombination between endogenous retroviral elements inherited in the cat genome and corresponding regions of the envelope (env) gene from FeLV subgroup A (FeLV-A). In vivo infectivity for FeLV-B is thought to be inefficient in the absence of FeLV-A. Proposed FeLV-A helper functions include enhanced replication efficiency, immune evasion, and replication rescue for defective FeLV-B virions. In vitro analysis of the recombinant FeLV-B-like viruses (rFeLVs) employed in this study confirmed these viruses were replication competent prior to their use in an in vivo study without FeLV-A helper virus. Eight specific-pathogen-free kittens were inoculated with the rFeLVs alone. Subsequent hematology and histology results were within normal limits, however, in the absence of detectable viremia, virus expression, or significant seroconversion, rFeLV proviral DNA was detected in bone marrow tissue of 4/4 (100%) cats at 45 weeks postinoculation (pi), indicating these rFeLVs established a limited but persistent infection in the absence of FeLV-A. Altered cell tropism was also noted. Focal infection was seen in T-cell areas of the splenic follicles in 3/4 (75%) rFeLV-infected cats analyzed, while an FeLV-A-infected cat showed focal infection in B-cell areas of the splenic follicles. Nucleotide sequence analysis of the surface glycoprotein portion of the rFeLV env gene amplified from bone marrow tissue collected at 45 weeks pi showed no sequence alterations from the original rFeLV inocula.

Animals↗

Association of hepatitis E virus with an outbreak of hepatitis at a military training camp in Nepal.

From 29 January 1995 to 15 March 1995, an outbreak of hepatitis occurred among 692 soldiers at an isolated training camp 25 km east of Kathmandu. Thirty-two cases occurred approximately 8 weeks after arrival of soldiers at the camp. To determine the etiology of the outbreak, patient sera were examined for evidence of infection with hepatitis A, B, C, and E viruses using commercially available enzyme-linked immunosorbent assay (ELISA) kits. The polymerase chain reaction (PCR) was used to detect hepatitis E virus (HEV) RNA. Evidence of recent infection (IgM to HEV and/or HEV RNA) was found in all but two patients, whereas none had evidence of recent infection with hepatitis A, B, or C viruses. Therefore, the outbreak was attributed to HEV. Fecally contaminated drinking water was suspected as the source of the outbreak. To determine the extent of HEV infections among those without clinical hepatitis, sera from the remaining soldiers were examined for markers of HEV infection. Evidence of past infection (IgG to HEV in the absence of IgM or HEV RNA) was found among 204 soldiers (prevalence = 30%), leaving 488 individuals susceptible to infection at the onset of the outbreak. Evidence of recent infection was found among another 83 individuals. We conclude that most exposed, susceptible soldiers sustained HEV infection without experiencing overt hepatitis. If the levels of virus inoculum and prior immunity in this population were typical, inapparent infection may be the usual adult response to virus exposure in an endemic area.

Adult↗

Nasoethmoid schwannoma with intracranial extension. Case report and review of literature.

Schwannomas are very rare in the nose and paranasal sinuses; their presence both intra-and extracranially is still rarer. Here we present a case of nasoethmoid schwannoma with intracranial extension into anterior cranial fossa. Clinical, radiological, pathological and operative findings are discussed and the literature is reviewed. We recommend bifrontal craniotomy for removal of intracranial and nasoethmoid extensions of this tumor.

Adult↗

Osteoclastic differentiation by mononuclear phagocytes containing biomaterial particles.

Aseptic loosening of implant components is a common and important complication of both cemented and uncemented prosthetic joint replacements. Wear particles derived from organic polymer and metal implant biomaterials are commonly found within macrophages and macrophage polykaryons in the fibrous membrane between loose implant components and the host bone undergoing resorption. In order to determine whether biomaterial particle-containing, foreign-body macrophages may contribute to periprosthetic bone resorption, we cultured murine monocytes that had phagocytosed particles of biomaterials commonly employed in bone implant surgery [polymethylmethacrylate (PMMA), ultra-high molecular weight polyethylene (PE), titanium and chromium-cobalt] on bone slices and glass coverslips with UMR 106 osteoblast-like stromal cells in the presence of 1,25-dihydroxy-vitamin D3. Under these conditions, all biomaterial particle-containing, foreign-body macrophages differentiated into osteoclastic cells, i.e. tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells capable of extensive lacunar bone resorption. This study shows that particle phagocytosis by macrophages does not abrogate the ability of these cells to undergo osteoclast differentiation. These findings emphasise the importance of the foreign-body macrophage response to biomaterial wear particles in the pathogenesis of aseptic loosening.

Animals↗

The role of MRI in the diagnosis of occult hip fractures.

Undisplaced fractures of the hip can occasionally be difficult to diagnose on radiographs. We performed MRI scans on 33 patients who had post-traumatic painful hips but negative radiographs. Forty per cent of the patients had sustained a fractured neck of femur, 15 per cent had sustained an intertrochanteric fracture and 11 per cent had sustained other fractures around the hip; in one patient a tumour was demonstrated. No fracture was seen in 30 per cent of the patients scanned. MRI is well tolerated by elderly patients in pain, does not involve ionising radiation and provides early and accurate diagnosis in patients with X-ray negative post-traumatic hip pain.

Accidental Falls↗

Tuberculous Addison's disease: lack of normalization of adrenocortical function after anti-tuberculous chemotherapy.

OBJECTIVE: Tuberculosis of the adrenal glands is a common cause of Addison's disease in developing countries. We conducted a study to determine if treatment of such patients with modern anti-tuberculous chemotherapy would lead to an improvement in plasma cortisol and aldosterone levels. DESIGN: Prospective study. PATIENTS: 5 patients with Addison's disease secondary to tuberculosis. MEASUREMENTS: Basal and ACTH stimulated plasma cortisol and aldosterone levels were measured prior to instituting anti-tuberculous chemotherapy, as well as one month after its conclusion. Four patients were again studied over the next 2-5 years. RESULTS: Peak plasma cortisol levels prior to treatment were markedly reduced (range, < 14-110 mumol/l). There was no improvement one month (< 14-143 mumol/l) or 2-5 years (< 14-69 mumol/l) after completing anti-tuberculous chemotherapy. Peak plasma aldosterone at diagnosis was < 56-210 pmol/l; it was undetectable in 4 patients. No improvement was observed one month (< 56-210 pmol/l), or 2-5 years (< 56-389 pmol/l) after stopping anti-tuberculous chemotherapy. Plasma aldosterone levels at both these time points were far lower than those in control subjects (median 736 pmol/l, 560-1512 pmol/l; p < 0.01). One patient had an increase in peak aldosterone from < 56 pmol/l to 389 pmol/l, though peak cortisol actually declined in this subject (from 110 mumol/l to 69 mumol/l). CONCLUSIONS: Treatment of tuberculous Addison's disease with anti-tuberculous chemotherapy does not lead to normalization of ACTH stimulated plasma cortisol or aldosterone levels during the 2-5 year period of study. However, prolonged follow up with regular adrenal function tests is warranted in all such patients.

Addison Disease↗

Facial expressions of emotions and schizophrenia: a review.

It is generally agreed that schizophrenia patients show a markedly reduced ability to perceive and express facial emotions. Previous studies have shown, however, that such deficits are emotion-specific in schizophrenia and not generalized. Three kinds of studies were examined: decoding studies dealing with schizophrenia patients' ability to perceive universally recognized facial expressions of emotions, encoding studies dealing with schizophrenia patients' ability to express certain facial emotions, and studies of subjective reactions of patients' sensitivity toward universally recognized facial expressions of emotions. A review of these studies shows that schizophrenia patients, despite a general impairment of perception or expression of facial emotions, are highly sensitive to certain negative emotions of fear and anger. These observations are discussed in the light of hemispheric theory, which accounts for a generalized performance deficit, and social-cognitive theory, which accounts for an emotion-specific deficit in schizophrenia.

Emotions↗

UVB-induced photodamage to phycobilisomes of Synechococcus sp. PCC 7942.

The effect of UVB irradiation on the phycobilisomes (PBSs) of Synechococcus sp. PCC 7942 cells was studied. The sucrose density-gradient-isolated PBSs from in vivo UVB-treated (280-320 nm) cells showed a strong decrease in beta-phycocyanin (beta PC) and alpha-phycocyanin (alpha PC) polypeptides, in addition to a decrease in the linker polypeptides LCM 75 (linker connecting the core to the thylakoid membranes), LR 33 (linker in the rod structure), LRC 31.5 (linker connecting the rod to the core) and LRC 29. In vitro UVB treatment of gradient-isolated intact PBSs for 1 h had no effect on any of the constituent polypeptides, and only after 2 h was a degradation of LCM 75 and LR 33 and a decrease in beta PC evident. Further investigation of phycobiliproteins (4 h of UVB irradiation) using polyclonal antibody directed against purified whole PBSs revealed that, in vivo, there was a gradual decline in the levels of LCM 75, LR 33, LRC 31.5, LRC 29, beta PC and alpha PC.

Animals↗

Processing of facial expressions of emotion and alexithymia.

OBJECTIVE: The primary objective was to examine emotional responsiveness in alexithymia. DESIGN: A quasi-experimental design was followed with the alexithymia variable being manipulated by subject stratification based on Toronto Alexithymia Scale-20-H. METHOD: Alexithymics (N = 12) and non-alexithymics (N = 12) were asked to match, label and verbally describe photographs displaying facial emotions along with TAT card II. RESULTS: Alexithymics did not differ from non-alexithymics in emotional matching and labelling tasks but had significant difficulty in verbally describing emotional expressions as evident by less duration of utterance, greater response latency and increased linguistic-type speech disruptions. Speech disruptions did not produce a group difference for TAT card II. CONCLUSION: Such difficulty in alexithymics may be associated with their inability to use emotional words in the appropriate context.

Adult↗

RNA profile and structural protein analysis of rotaviruses isolated from diarrhoeal calves in India.

Two isolates of group A rotaviruses (CR129 and CR156) were isolated from faecal samples of diarrhoeal calves reared in two dairy farms at Hisar (Haryana, India) by using MA-104 cell lines. These isolates were compared with three standard reference bovine rotaviruses, UK, NCDV and B223, to reveal differences, if any, in their genome and protein migration profiles. The migration of RNA segment 4 of CR129 was slower than that of NCDV, but faster than that of UK. Segment 10 of CR156 moved faster than that of the reference viruses. The segments 2 and 3 co-migrated in CR129, but resolved separately in CR156. Five protein bands of size 116-120 KD (VP1), 95 KD (VP2), 90 KD (VP3/VP4), 44 KD (VP6) and 34 KD (VP7) were detected by protein analysis. No significant difference was observed in the protein profile of these two bovine rotavirus isolates by immunoblotting. However, VP1 was of approximately 116 KD size in the two isolates, compared to 120 KD in the reference strains. These findings indicate that these rotaviruses isolated from diarrhoeic Indian calves differed from the 3 reference strains.

Animals↗

Bilateral transfer deficit in schizophrenia: a trait marker.

Schizophrenic patients who had shown improvement over a 6-week treatment period were tested for their bilateral transfer of skill with a mirror-drawing task. Compared with first degree relatives and normal control subjects, patients showed a significant deficit in bilateral transfer of skills in terms of response accuracy both before and after treatment. These findings indicate that the deficit is an enduring functional loss in schizophrenia.

Adult↗