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Biomedical subjects

K Prakash

Publications and source records attributed to K Prakash.

At least 19 recordsLinked to original sources
PubMed2006

Postoperative seizures after extratemporal resections and hemispherectomy in pediatric epilepsy.

OBJECTIVES: To estimate frequency and risk factors for acute postoperative seizures (APOS) within the first week after extratemporal cortical resection (ETR) and hemispherectomy (HS) in children and to assess the predictive value of APOS on long-term seizure outcome in this group. METHODS: The authors conducted a retrospective analysis of children (< 18 years), who underwent ETR or HS for intractable epilepsy between 1995 and 2002. APOS features and seizure outcome after ETR or HS were obtained at 6, 12, and 24 months. Univariate logistic regression was used for risk factors of APOS and life table analysis and log rank tests for seizure outcome at 0 to 6, 6 to 12, and 12 to 24 months. RESULTS: Of 132 patients, 34 (26%) had APOS. APOS were more frequent after ETR (26/71) than HS (8/61) (p < 0.01). APOS, irrespective of their timing, number, semiology, or other perioperative complications, were an independent predictor of poor postoperative seizure outcome at 2 years (p < 0.001). The estimated odds of postoperative Engel class I outcome in the APOS vs non-APOS categories was 0.27 (73% less likely) for 0- to 6-month, 0.22 (78% less likely) for 6- to 12-month, and 0.13 (87% less likely) for the 12- to 24-month intervals. CONCLUSIONS: Acute postoperative seizures (APOS) occur in 26% children, and the risk is higher after extratemporal cortical resection than hemispherectomy. APOS predict a poor postoperative seizure outcome at 6, 12, and 24 months. This study is useful for counseling families after epilepsy surgery. It also suggests that APOS may not be discounted as "benign" in research studies that evaluate seizure outcomes after epilepsy surgery.

Adolescent↗
PubMed2006

Prevalence of blindness and cataract surgery in Gandaki Zone, Nepal.

BACKGROUND/AIM: Himalaya Eye Hospital (HEH), established in 1993, is rendering eye care services in the Gandaki and Dhaulagiri zones. The hospital has extensive community outreach activities along with services for outpatients, emergencies, and subspecialties such as vitreoretinal, paediatric, and low vision. The operation theatre is well equipped to match the surgical needs including phaco surgery for cataract. The hospital has performed more than 14 000 cataract surgeries and 250 000 treatment services during this period. The aim of this study was to estimate the prevalence of blindness, visual impairment, and cataract surgical coverage among the older adult population of three districts of Gandaki Zone, where 80% of the hospital's service recipients reside. METHODS: People aged 45 years and older were enrolled in the study using a stratified cluster design. Subjects in 25 randomly selected clusters from the listed 806 were recruited through door to door visits. Each recruited subject had visual acuity (VA) and clinical examination conducted by an ophthalmologist. The survey was preceded by pre-pilot and pilot studies to refine the operational method. To assess quality assurance the interobserver variation in VA measurement was also carried out in five different clusters. RESULTS: Out of 5863 selected subjects 85.3% were examined. Blindness defined as presenting VA <6/60 in both eyes was found in 2.6% (95% confidence interval (CI): 2.2 to 3.9), whereas 16.8% individuals examined had vision <6/19 in one or both eyes. Cataract was the principal cause of blindness in 60.5%, and refractive error was the dominant cause of vision impairment (<6/19) 83.3%. Cataract surgical coverage was 59.5% among the cataract blind and associated with younger age, literacy, and male sex. CONCLUSION: The finding suggests a positive impact of the HEH programme on the prevalence of blindness and cataract surgical services in the survey area. Strategies to further improve access and utilisation of facilities and increase cataract surgical coverage need to be developed.

Age Factors↗
PubMed2005

Changes in astigmatism in children with congenital nystagmus.

BACKGROUND: Astigmatism is commonly reported in children with and without nystagmus. In children less than 4 years of age the astigmatism changes from against the rule (ATR) to with the rule (WTR) astigmatism in children without nystagmus. However, little is known about children with congenital nystagmus. We compared astigmatism in children with congenital nystagmus below 4 years and above 4 years of age. MATERIAL AND METHODS: Three hundred and fifty-six eyes in 178 children who satisfied the study criteria were included. The children were divided into those below 4 years of age (n of eyes = 192) and those above (n of eyes = 164). Cycloplegic refraction (with manual retinoscopy) carried out at presentation and at the last follow-up were recorded and compared. Cycloplegia was achieved using cyclopentolate eye drops. Outcome of eyes with no astigmatism at initial presentation was compared with the final refraction in both the age groups. The visual acuity at the first presentation was compared with the visual acuity at the last presentation. RESULTS: Average follow-up duration was 3.36+/-1.59 years. On presentation, 176 (49.44%) eyes did not have any astigmatism. We found that 26 (25.2%) out of the 103 children below 4 years of age who did not have any astigmatism on presentation developed WTR astigmatism after a mean follow-up of 3.5+/-1.5 years. (p= 0.042). In children >or=4 years of age only 7 (9.6%) children out of 73 developed WTR after a mean follow-up of 3.4+/-1.4 years. The visual acuity change was not found to be significant in the two groups. The majority (90.3%) improved or had same visual acuity in group A and 88.9% improved or had the same visual acuity in group B at the last follow-up (p= 0.77). DISCUSSION: Our incidence of WTR astigmatism in children with congenital nystagmus is similar to those previously reported series. Our data suggest that there is a significant chance that children under 4 years with congenital nystagmus may develop WTR astigmatism compared with children above 4 years of age. CONCLUSION: With the rule (WTR) astigmatism is common in children with nystagmus. Children under 4 years of age presenting with no astigmatism may acquire WTR astigmatism as they grow. The amount of astigmatism increases with age in children with nystagmus. Visual acuity, however, remains stable as the age advances.

Astigmatism↗
PubMed2003

Are some cases of infected pancreatic necrosis treatable without intervention?

BACKGROUND: Infected pancreatic necrosis is considered an absolute indication for interventional management such as percutaneous drainage or surgery. The presence of retroperitoneal air is a sign of anaerobic sepsis. METHOD: A retrospective review of case records of patients presenting with severe acute pancreatitis and pancreatic necrosis was performed to identify cases in whom conservative treatment was followed by a satisfactory outcome. RESULTS: Four patients were identified over a 3-year period who had pancreatic necrosis and retroperitoneal air; they were treated with antibiotics and intensive care, and they improved without any interventional treatment. CONCLUSIONS: Some patients with infected pancreatic necrosis are treatable medically. The clinical status of the patients may well be a more important factor governing the choice of the treatment approach than bacteriological findings of infection alone.

Adult↗
PubMed2003

Port-site tuberculosis after laparoscopy: report of eight cases.

In light of the explosive increase in laparoscopic surgery, there is concern about the effectiveness of sterilizing reusable laparoscopic instruments by immersion in 2% glutaraldehyde. This article describes the clinical features of eight patients who presented with biopsy-proven tuberculosis at the port-site unassociated with other clinical features of tuberculosis. Three of the eight patients had positive cultures for Mycobacterium tuberculosis. The port-site sinuses healed with antituberculous chemotherapy. There is conflicting information in the literature regarding the effectiveness of a 20-min instrument soak in 2% glutaraldehyde to clear M. tuberculosis. In light of the preceding information, the current practice of glutaraldehyde disinfection for reusable laparoscopes needs to be reexamined.

Adult↗
PubMed2001

Laparoscopic cholecystectomy in acute cholecystitis.

BACKGROUND: In the light of laparoscopic cholecystectomy increasingly applied to all forms of cholecystitis, this study aimed at evaluating the safety of laparoscopic cholecystectomy applied to all cases of acute cholecystitis, and at determining factors associated with the risk of conversion to open cholecystectomy. METHODS: The clinical, biochemical, radiologic, and operative data from 124 consecutive cases of acute cholecystitis were analyzed retrospectively to determine the complications and morbidity after operation. The data were analyzed further by univariate and multivariate analysis to identify factors associated with conversion. RESULTS: No major bile duct injury or mortality occurred. Bile leak from the stump of the cystic duct developed in four patients. These were managed successfully by endoscopic biliary stent placement. The mean duration of hospital stay was 3.8 days in the laparoscopic group and 8.2 days in the open group. Of the 124 patients (18.5%), 23 underwent conversion to open cholecystectomy. Univariate analysis identified the following factors as associated with conversion: common duct dilation greater than 7 mm observed on ultrasound, (p < 0.05), pericholecystic collection seen on ultrasound (p < 0.0001), emphysematous cholecystitis (p < 0.01), endoscopic retrograde cholangiopancreatographic evidence of Mirizzi syndrome (p < 0.05), and pericholecystic collection at operation (p < 0.0001). On multivariate analysis, only pericholecystic collection (p < 0.015) and gallbladder wall thickness greater than 5 mm (p < 0.013) were statistically significant. CONCLUSIONS: Laparoscopic cholecystectomy for acute cholecystitis can be applied safely to all comers, offering the advantage of a shortened hospital stay. Pericholecystic collection, as observed on ultrasound, is associated with a high risk of conversion to open cholecystectomy.

Acute Disease↗
PubMed2000

Future molecular approaches to the diagnosis and treatment of glomerular disease.

Current diagnoses and treatment decisions for renal disease are made based upon a combination of clinical and pathological determinations. With the advances in both biochemical and molecular biological techniques, identifying the underlying biochemical and genetic changes that may have initiated and/or contributed to the disease is possible. We describe here technologies that may lead to significant changes in renal disease diagnosis, characterization, treatment, and potentially prevention. For example, differential display techniques and DNA gene chip arrays show the changes in mRNA expression patterns and can potentially identify previously unknown genes and reveal new roles for previously known genes in renal disease. The generation of the single nucleotide polymorphisms (SNP) genomic map will facilitate genetic screening that may identify a gene or combination of genes that produce enhanced disease susceptibility. Combining genomic analysis with epidemiological studies may identify environmental factors that contribute to renal disease onset in genetically susceptible individuals. A number of novel therapies are already on the horizon. These include reagents that abrogate the function of specific cytokines, chemokines, and effector cells. With the list of renal disease genes in hand, their role in renal physiology and pathophysiology can be determined, which should lead to the discovery of pharmacological intervention directed at those genes and their products that play a role in the pathogenesis of renal disease.

Biotechnology↗
PubMed1999

8-anilino-1-naphthalene sulfonic acid (ANS) induces folding of acid unfolded cytochrome c to molten globule state as a result of electrostatic interactions.

Hydrophobic interaction of 8-anilino-1-naphthalene sulfonic acid (ANS) with proteins is one of the widely used methods for characterizing/detecting partially folded states of proteins. We have carried out a systematic investigation on the effect of ANS, a charged hydrophobic fluorescent dye, on structural properties of acid-unfolded horse heart cytochrome c at pH 2.0 by a combination of optical methods and electrospray ionization mass spectroscopy (ESI MS). ANS was found to induce, a secondary structure similar to native protein and quenching of fluorescence of tryptophan residue, in the acid-unfolded protein. However, the tertiary structure was found to be disrupted thus indicating that ANS stabilizes a molten globule state in acid-unfolded protein. To understand the mechanism of ANS-induced folding of acid-unfolded cytochrome c, comparative ESI MS, soret absorption, and tryptophan fluorescence studies using nile red, a neutral hydrophobic dye, and ANS were carried out. These studies suggested that, at low pH, electrostatic interactions between negatively charged ANS molecules and positively charged amino acid residues present in acid-unfolded cytochrome c are probably responsible for ANS-induced folding of acid-unfolded protein to partially folded compact state or molten globule state. This is the first experimental demonstration of ANS induced folding of unfolded protein and puts to question the usefulness of ANS for characterization/determination of partially folded intermediates of proteins observed under low pH conditions.

Anilino Naphthalenesulfonates↗
PubMed1997

The effect of tibiotalar fixation on foot biomechanics.

Contact areas and peak pressures in the posterior facet of the subtalar and the talonavicular joints were measured in cadaver lower limbs for both the normal limb and after fixation of the tibiotalar joint. Six joints were fixed in neutral, in 5-7 degrees of varus and of valgus. Ten degrees of equinus angulation was also studied. Each position of fixation was tested independently. Neutral was defined as fixation without coronal or sagittal plane angulation compared with prefixation alignment of the specimen. When compared with normal unfused condition, peak pressures increased, and contact areas decreased in the subtalar joint for specimens fixed in neutral, varus, and valgus. However, the change in peak pressure for neutral fusion compared with normal control was not statistically significant (P > 0.07). Peak pressures for varus and valgus fixation were significantly different from normal (P < 0.001). Contact areas for all positions of fixation were significantly different from normal (P < 0.001). Coronal plane angulation, however, also resulted in significantly lower contact areas compared with neutral fixation (P < 0.001). Contact areas and peak pressures in the talonavicular joint did not appear to be substantially affected by tibiotalar fixation with coronal plane angulation. Equinus fixation qualitatively increased contact areas and peak pressures in the talonavicular and posterior facet of the subtalar joint. Neutral alignment of the tibiotalar joint in the coronal and sagittal planes altered subtalar and talonavicular joint contact characteristics the least compared with normal controls. Therefore, ankle fusion in the neutral position would be expected to most closely preserve normal joint biomechanics and may limit the progression of degenerative arthrosis of the subtalar joint.

Adult↗
PubMed1997

Neonatal nosocomial infection: profile and risk factors.

OBJECTIVE: To determine the incidence and risk factors for neonatal nosocomial infections. DESIGN: Cohort study. SETTING: Tertiary care Teaching Hospital. METHODS: Hospital born neonates transferred to the neonatal unit after birth and available in the unit 48 hours later comprised the cohort for the surveillance. Detailed maternal, intrapartum and neonatal variables were recorded. Risk factors for nosocomial infection were analyzed by both univariate and multiple logistic regression methods. RESULTS: One hundred and thirty-four neonates were enrolled in the cohort. The overall nosocomial infection rate was 16.8/1000 patient days. Device associated infection rate was 11.9/1000 device days. Multidrug resistant Klebsiella species was the commonest organism causing nosocomial septicemia and pneumonia followed by Pseudomonas aeruginosa. The risk factors detected to be significantly associated with infection on multiple logistic regression analyses were a birth weight < 1500 g (OR 3.3) and assisted ventilation > 72 h (OR 14.2). CONCLUSIONS: Very low birth weight (VLBW) neonates, especially those undergoing interventions such as mechanical ventilation are at the greatest risk for infection and death. Therefore, strict protocol for asepsis must be adhered to when handling these high risk infants.

Analysis of Variance↗
PubMed1996

Multiplex selection technique (MuST): an approach to clone transcription factor binding sites.

We have used a multiplex selection approach to construct a library of DNA-protein interaction sites recognized by many of the DNA-binding proteins present in a cell type. An estimated minimum of two-thirds of the binding sites present in a library prepared from activated Jurkat T cells represent authentic transcription factor binding sites. We used the library for isolation of "optimal" binding site probes that facilitated cloning of a factor and to identify binding activities induced within 2 hr of activation of Jurkat cells. Since a large fraction of the oligonucleotides obtained appear to represent "optimal" binding sites for sequence-specific DNA-binding proteins, it is feasible to construct a catalog of consensus binding sites for DNA-binding proteins in a given cell type. Qualitative and quantitative comparisons of the catalogs of binding site sequences from various cell types could provide valuable insights into the process of differentiation acting at the level of transcriptional control.

Amino Acid Sequence↗
PubMed1996

Imaging in phaeohyphomycosis of the brain: case report.

A case of multiple, conglomerated brain abscesses due to Xylohypha bantiana, with unique imaging features, is presented. This is the first culture-proven case of brain infection due to this fungus in the neuroimaging literature.

Brain Abscess↗
PubMed1996

Detection of antibody to C-carbohydrate of group A streptococci with enzyme-treated whole bacterial cells as antigen for ELISA.

Antibody to specific cell-wall carbohydrate of group A streptococci in human sera was determined by enzyme-linked immunosorbent assay (ELISA) with enzyme-treated whole cells and purified group A carbohydrate (ACHO) as antigens. The optimal concentration of enzyme-treated whole bacterial cells to coat wells was 2 x 10(8) cells/ml and for purified ACHO antigen the optimal concentration was 1 microgram/ml. Sera from patients with acute rheumatic fever and acute glomerulonephritis were screened for the presence of C-carbohydrate antibodies. Patients with acute post-streptococcal complications showed significantly higher titres of antibody when compared with normal healthy individuals. ELISA results were also compared with purified ACHO as an antigen; this showed a highly significant correlation (r = 0.73). Results showed that measurement of the anti-ACHO antibody by ELISA with enzyme-treated whole cells can be a useful, reliable and simple method for serological diagnosis of group A infection and sequelae.

Antibodies, Bacterial↗
PubMed1996

Type-specific antibodies to purified streptococcal M proteins from potentially rheumatogenic M-types in patients with rheumatic fever and rheumatic heart disease.

This study was designed to identify the predominant serotypes of group A streptococci (GAS) responsible for rheumatic fever (RF) and rheumatic heart disease (RHD) in India. RF and RHD sera were screened for antibodies to M proteins retrospectively against known rheumatogenic M types and M types isolated from patients with acute RF. All GAS strains isolated from four patients with acute RF in a short outbreak of RF, were identical - serum opacity factor (SOF) negative, T-pattern 3/13 B3264 and M-non-typable. Because of this, M protein was isolated from only one of these four M-non-typable strain (S-399). This was done by limited pepsin digestion and purification by ion-exchange chromatography on DEAE-Sephadex, followed by gel filtration. Purified M protein was found to be homologous on SDS-PAGE (mol.wt 20 kDa), immunogenic in rabbits and to retain its antigenic structure. This purified M protein from an M-non-typable strain (pep-MNT) was used as an antigen to screen RF and RHD sera retrospectively by ELISA for the prevalence of the M-non-typable GAS strain. The prevalence of the M-non-typable strain was compared with that of the known rheumatogenic M types. Results suggest that the M-non-typable strain could be a provisional new rheumatogenic M type in India and could be a candidate for a multivalent M-protein vaccine to control RF and RHD.

Adolescent↗
PubMed1995

Functional characterization of the cis-regulatory elements of the rat ribophorin I gene.

The ribophorin I gene encodes a rough endoplasmic reticulum (RER) specific membrane protein which is a subunit of the oligosaccharyltransferase. To establish the functional activity of its promoter region we have performed transient gene transcription experiments employing plasmid constructs that contain 5' flanking regions of the ribophorin I gene cloned upstream of the CAT reporter gene. Among the restriction fragments obtained from the 1.3-kilobase 5' flanking region, a proximal fragment (-42 to +24) containing two GC-rich elements was required for basic promoter activity, while a fragment (-364 to +24) encoding an additional GC-box and an octamer like motif at -233 conferred the maximal promoter activity. In order to investigate the functionality of an octomer-like sequence co-transfection experiments were performed with Oct-2 cDNA and the CAT reporter gene containing the ribophorin I fragment (-364 to +24). A 3-4-fold increase in the transcriptional activity was observed with this construct. In addition, gel shift experiments showed Oct-2 binding to this construct. These results indicate that Oct-2 is most likely involved in the regulation of the ribophorin I gene transcription. We suggest that the GC-rich elements are necessary for constitutive ribophorin I expression while octamer motif binding proteins function synergistically with the GC-rich element binding proteins to increase the expression of the ribophorin I gene during the proliferation of RER.

Animals↗
PubMed1994

DNA-binding proteins that interact with the 19-base pair (CRE-like) element from the HCMV major immediate early promoter in differentiating human embryonal carcinoma cells.

The pluripotent human embryonal carcinoma (EC) cell line NTERA-2 provides a useful tool for investigating cell differentiation in a way that is pertinent to the development of the early human embryo. The major immediate early (MIE) gene of human cytomegalovirus (HCMV), which is not transcribed in undifferentiated NTERA-2 EC cells but is transcribed in their differentiated derivatives, offers a model with which to study the developmental regulation of gene activity during the differentiation of these cells. We have investigated the regulatory activity of the cAMP response elements (CRE) and the activation protein (AP1) site found within several repeated 19-base-pair (bp) elements from the HCMV MIE promoter, and the developmental regulation of nuclear DNA-binding factors that interact with these sites. The 19-bp CRE but not the AP1 site is responsive to cAMP in undifferentiated NTERA-2 EC and its activity is enhanced upon differentiation. Nuclear proteins of the CREB, Fos, and Jun families bind to these sites, but, surprisingly, their levels only show limited regulation during NTERA-2 differentiation. This contrasts with results obtained with murine EC cells. However, additional and apparently novel proteins with molecular weights between 80,000 and 90,000, and binding specificities for both CRE and AP1 sites, were detected in undifferentiated EC cells. The activity of these proteins decreased markedly after differentiation, indicating their involvement in negative regulation of the CRE/AP1-like site in undifferentiated EC cells. This suggests novel members able to interact via leucine zippers with other members of the Jun-Fos-CREB family of DNA binding proteins that are also involved in this regulation.

Antibodies, Monoclonal↗
PubMed1993

CD4-independent infection of human peripheral blood dendritic cells with isolates of human immunodeficiency virus type 1.

Dendritic cells (DC) are members of a distinct family of bone marrow-derived leukocytes. DC are potent accessory cells for a number of T cell-mediated immune responses, including autologous and allogeneic mixed leukocyte reactions, and mitogen- and antigen-stimulated lymphocyte proliferation. In the present study, DC purified from human peripheral blood were inoculated with various strains (IIIB, SF2, WMJ1, SF162, 89.6 and clone HXB2) of human immunodeficiency virus type 1 (HIV-1) displaying different patterns of cellular tropism. Viral replication was demonstrated by detection of p24 antigen (Ag) intracellularly and in culture supernatants, and by Southern and Northern blot analyses for the presence of HIV DNA and RNA, respectively, within infected cells. Cell-free and cell-associated p24 Ag levels rose substantially when DC were inoculated with strains SF162, 89.6 and clone HXB2. In contrast, p24 Ag levels rose only marginally after inoculation of DC with strains IIIB, SF2 and WMJ1. Purified DC did not express detectable membrane CD4, although CD4 mRNA was detected by reverse transcriptase PCR. The presence of anti-CD4 monoclonal antibodies failed to block infection of DC by any of the HIV strains tested, suggesting the existence of a CD4-independent alternative pathway of viral entry. The possibility that DC serve as a reservoir for HIV-1 must be considered.

Adult↗