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Biomedical subjects

K S Kumar

Publications and source records attributed to K S Kumar.

At least 37 records · Page 2Linked to original sources
PubMed2001

Dynamics of the 16O(e, e'p) reaction at high missing energies.

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

Journal Article↗
PubMed2001

Avulsion fractures of the anterior inferior iliac spine: the case for surgical intervention.

Two cases of avulsion fracture of the anterior inferior iliac spine are reported. One was a missed diagnosis that resulted in exostosis formation needing excision. The second case was an adolescent with significant displacement of the fragment and a primary open reduction and internal fixation was done. A high index of suspicion is necessary to diagnose this relatively rare injury and surgery has a role in carefully selected cases.

Adolescent↗
PubMed2001

Parental age and the origin of extra chromosome 21 in Down syndrome.

We present a report of the parental ages (n = 865) and parental origin of meiotic nondisjunction (n = 236) that are likely to show a predisposition in the etiology of Down syndrome (DS). Chromosomal analysis, performed over a 20-year period, on 1,001 Down syndrome subjects, revealed pure trisomy 21 karyotype in 880 subjects (87.92%), mosaic trisomy karyotype in 77 (7.69%), and translocation karyotype in 44 (4.39%). The mean maternal age was found to be 30.34 years, and mean paternal age was 31.04 years. Nondisjunctional error was 79.24% maternal and 20.76% paternal. The findings of the study revealed the significant contribution of advanced parental age and increased maternal meiotic nondisjunctional error to the origin of trisomy 21 Down syndrome.

Adult↗
PubMed2001

Synthesis of esculentin-1 antibacterial peptide fragments on 1,4-butanediol dimethacrylate cross-linked polystyrene support.

Peptide segments corresponding to antibacterial esculentin-1 (1-15), (3344), (9-27), and their modified forms were synthesized on 1,4-butanediol dimethacrylate cross-linked polystyrene (PS-BDODMA) support. Hydroxymethyl and aminomethyl 2% PS-BDODMA supports were used for the synthesis. The HMPB linker was appended to the aminomethyl resin using HBTU in presence of HOBt and the first amino acid was incorporated using MSNT. The conventional Fmoc synthetic protocol was used for the synthesis of peptides. The peptides were cleaved from the support using TFA. The peptides were purified by HPLC, and characterized by amino acid analysis and MALDI TOF MS. The secondary structures of the peptides were revealed by CD measurements. The synthesis of these peptides illustrates the utility of the new support for the synthesis of long-chain bioactive peptides. The synthetic peptides were tested for antimicrobial activity against Escherichia coli Mos blue, E. coli 2, Bacillus brevis, B. megaterium, Pseudomonas HTL, and Vibrio mimicus. The antibacterial activity of the peptides was explained on the basis of the helicity and charged nature of the sequences.

Amino Acid Sequence↗
PubMed2001

Cholestatic presentation of chronic hepatitis C: a clinical and histological study with a review of the literature.

Bile duct lesions are observed in the livers of chronic hepatitis C patients, but are inconstant and rarely associated with other features of chronic cholestasis and progressive bile duct injury or loss. We aimed to identify the clinical and biochemical characteristics of patients with chronic hepatitis C from our patient database presenting with prominent cholestatic features to determine if there is a correlation between histological evidence of bile duct injury and clinical or biochemical features observed in these patients. We retrospectively reviewed a hepatitis C database including 620 patients to identify those who presented with either alkaline phosphatase (AP) > or = 400 units/liter (normal 30-126 units/liter) or AP > or = 250 units/liter with pruritus. All patients were negative for anti-mitochondrial antibody (AMA). Appropriate exclusion criteria were used to exclude patients with other confounding factors. Histological features were compared with age- and sex-matched controls selected randomly from our hepatitis C database. Thirty-two patients were identified as meeting the above criteria. Twenty-four were excluded for the presence of other confounding factors and two for lack of liver biopsy. There were two men and four women. The mean age was 47 +/- 9 years. Four of the six presented with pruritus, which was severe in three. Liver biopsy showed evidence of moderate to severe fibrosis in all but one patient. Evidence of bile duct injury was seen in all patients and tended to be more severe than in controls. Bile ductular proliferation and mild ductopenia were the most commonly observed findings. A subset of patients with chronic hepatitis C may present with prominent cholestatic features. The majority of these patients present with pruritus and have histological evidence of bile duct injury, which may be progressive.

Adult↗
PubMed2001

Syntheses, characterization and application of cross-linked polystyrene-ethyleneglycol acrylate resin (CLPSER) as a novel polymer support for polypeptide syntheses.

Cross-linked polystyrene-ethyleneglycol acrylate resin (CLPSER) was developed for the solid-phase synthesis of peptide by introducing a cross-linker, O,O'-bis(2-acrylamidopropyl)polyethylene glycol(1900) (Acr(2)PEG), into polystyrene. The cross-linker was prepared by treating acryloyl chloride with O,O'-bis(2-aminopropyl) polyethylene glycol(1900) [(NH(2))(2)PEG] in the presence of diisopropylethylamine. The copolymer was prepared either by bulk or inverse suspension copolymerization of Acr(2)PEG(1900) and styrene using sorbitan monolaurate as the suspension stabilizer, and a mixture of ammonium peroxodisulfate and benzoyl peroxide as the radical initiators. The resin was characterized using gel-phase (13)C NMR, infrared (KBr) spectroscopic techniques and the morphological features of the resin were investigated using scanning electron microscopy photographs. CLPSER showed excellent swelling in a broad range of solvents and was found to be chemically inert to various reagents and solvents used in solid-phase peptide synthesis. To demonstrate the usefulness of the new resin in polypeptide synthesis, the support was derivatized with an 'internal reference' amino acid (norleucine) and a handle 4-(4-hydroxymethyl-3-methoxy)butyric acid. The new resin was compared with commercial supports such as Merrifield and Sheppard resins by synthesizing an acyl carrier protein (65-74) fragment under the same experimental conditions. HPLC profiles revealed the high efficiency of the newly developed support. Resin capability in peptide synthesis was further demonstrated by the solid phase synthesis of a 25-residue peptide from the E2/NS1 region hepatitis C viral polyprotein.

Acrylates↗
PubMed2001

Isolated intrahepatic biliary dilatation in a patient with acquired immune deficiency syndrome (AIDS): AIDS cholangiopathy versus incidental unilobar Caroli's disease.

We describe a case of possible monolobar Caroli's disease in a patient with acquired immune deficiency syndrome (AIDS) who presented with features of cholangitis. Diagnostic workup, which included endoscopic retrograde cholangiography, revealed focal intrahepatic biliary dilatation confined to the right lobe. The patient subsequently underwent right hepatic lobectomy. Pathology revealed multiple cysts filled with calculi and inflammation in the cyst walls. Special stain results for fungi and acid-fast organisms were negative. The presence of advanced AIDS in this patient raised the possibility of this being a possible manifestation of AIDS cholangiopathy.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Spontaneous fungal peritonitis (Candida glabrata) in a patient with cirrhosis.

We report a case of spontaneous fungal peritonitis in a patient with cirrhosis. A 70-year-old woman with cirrhosis secondary to autoimmune hepatitis was admitted with fever and abdominal distention. Paracentesis revealed neutrocytosis, and despite appropriate antibacterial coverage, no clinical improvement was noted and the ascitic fluid white cell count increased on repeat paracentesis. Two consecutive ascitic fluid cultures grew Candida glabrata, and antifungal therapy with amphotericin was initiated, pending sensitivity of the isolate. Because of worsening renal function, amphotericin was discontinued and itraconazole was started, as sensitivity of the isolate was then available. Antifungal therapy resulted in resolution of ascitic fluid neutrocytosis and culture negativity. However, the patient's renal function continued to deteriorate, necessitating hemodialysis. Despite multiple courses of antibiotics, she died of fulminant sepsis and multiorgan failure.

Aged↗
PubMed2001

Syntheses of immunodominant peptide regions of hepatitis C viral pathogens using PS-BDODMA resin: a single peptide derived from the conserved domain (E2/NS1) was highly effective in detecting anti-HCV antibodies.

Peptides were synthesized with very high purity and yield on a highly solvating copolymer of 1,4-butanediol dimethacrylate cross-linked polystyrene support (PS-BDODMA). The polymer was synthesized by radical aqueous suspension polymerization using toluene as the diluent and 1% polyvinyl alcohol as the suspension stabilizer. The supports were highly resistant to various chemical reagents and solvents that are frequently used in polypeptide synthesis. The peptides synthesized on this support were designed from the core (C), envelope (E1 and E2) and nonstructural protein (NS1-NS5) regions of the prototype hepatitis C viral (HCV) polyprotein, and were used to develop a peptide-based immunoassay (PBEIA) for the detection of HCV antibodies. The purity of these peptides was tested by HPLC. Peptide identity was confirmed by amino acid analysis and MALDI-TOF-MS. A single peptide chosen from a conserved area (E2/NS1) at the C-terminus of the hypervariable region (HVRI) was found to be sufficient for effective and reliable diagnosis of HCV infection in infected individuals, as well as also apparently healthy individuals. The CD spectrum of the peptide shows no preference for any ordered secondary structure. When used, peptide mixtures from various protein regions of HCV reduced the sensitivity and reliability of the diagnosis partly because of epitope masking.

Amino Acid Sequence↗
PubMed2001

Hands up: a case of bilateral inferior shoulder dislocation.

Inferior shoulder dislocation (luxatio erecta) is a rare form of shoulder dislocation. A case involving bilateral luxatio erecta with bilateral brachial plexus injury and rotator cuff tears is reported. A brief review of presentation and management of this condition is presented.

Accidental Falls↗
PubMed2001

Predominance of antibodies to hepatitis C virus envelope proteins in various disease statuses of hepatitis C.

The antibody profile to various proteins of hepatitis C virus (HCV) was studied in 113 patients positive for HCV RNA in various disease statuses of hepatitis C (HC). A single peptide (E2/NS1, aa 413-436 of HCV polyprotein) chosen from a conserved region at the C-terminus of the hypervariable region (HVR) HVR1 of HCV was found to be sufficient for reliable diagnosis of the infection, even in the acute phase. Six hundred and one suspected HC cases and 200 voluntary blood donors were tested by this peptide. The sensitivity of detection of HCV antibodies by this peptide did not increase with addition of peptides from other HCV proteins. Our results clearly demonstrate that antibodies to HCV envelope proteins occur in a higher percentage of the infected population than those to other proteins. This emphasizes the necessity of using representative sequences from HCV envelope proteins in diagnostic immunoassays of this viral infection.

Acute Disease↗
PubMed2001

Age-related proximal femur bone mineral loss in South Indian women: a dual energy X-ray absorptiometry study.

OBJECTIVES: i) To collect normative data for proximal femur bone mineral density (BMD) in South Indian women using dual energy X-ray absorptiometry (DXA) and ii) to study the rate and significance of hip bone mineral loss with advancing age in this population. MATERIAL AND METHODS: Forty five women, whose age ranged from 16 to 84 years were studied. This sample was drawn randomly from general medical practice at KJ Hospital, Chennai, South India during November, 1997 to April, 1998. Of these 45 cases, 21 were pre-menopausal (mean +/- SD age = 30.9+/-8.8 years) and 24 post-menopausal (mean +/- SD age = 62.1+/-11.0 years). Subjects with secondary bone diseases were excluded. Also excluded were those taking any drugs known to affect calcium metabolism e.g., thiazide diuretics, oestrogen and calcium. Subjects were divided into seven decadal age groups from 15-24 years to 75-84 years. BMD of the right proximal femur was evaluated using a QDR-1000 DXA bone densitometer (Hologic Inc., Waltham, Massachusetts, USA). Data analysis was done with SPSS/PC statistical software package. RESULTS: Linear regression analysis showed significant (p < 0.001) negative correlations between all hip BMD variables at different regions of interest and patient's age. Relative to that at 30 years of age, rates of BMD loss in the neck of femur, trochanter, intertrochanter, total hip and Ward's triangle were 0.68%, 0.65%, 0.58%, 0.61% and 1.05% per annum respectively. Over the age of 65 years, the above mentioned regions BMD decreased by 0.91%, 0.84%, 0.72%, 0.78% and 1.66% per annum respectively. CONCLUSION: Normative data for proximal femur BMD in South India women have been evaluated and it may prove useful for diagnosing osteoporosis in the women of South India.

Adolescent↗
PubMed2000

Syntheses of four peptides from the immunodominant region of hepatitis C viral pathogens using PS-TTEGDA support for the investigation of HCV infection in human blood.

Four peptides were designed and synthesized on a highly solvating copolymer of tetraethyleneglycol diacrylate cross-linked polystyrene (PS-TTEGDA) support with very high purity and yield. The polymer was synthesized in various cross-linking densities (1, 2, 3, 4, 5 and 10%) using radical aqueous suspension polymerization. Four per cent PS-TTEGDA resin showed rigidity and mechanical characteristics comparable with those of divinylbenzene cross-linked polystyrene (PS-DVB) support. Swelling and solvation characteristics of PS-TTEGDA were much higher than PS-DVB support in all solvents used in solid-phase peptide synthesis. Forty-eight hour treatment of the support with neat trifluoroacetic acid did not show any change in its infrared spectra. PS-TTEGDA could be functionalized with chloromethyl, aminomethyl and hydroxymethyl functional groups under various controlled conditions. Synthetic utility of the support was demonstrated by the synthesis of four peptides selected from the envelope and nonstructural protein region of the prototype hepatitis C virus (HCV). These peptides were later used successfully to develop a peptide-based immunoassay (PBEIA) for the detection of HCV immunity. Peptides designed from the NS1 and NS4 protein regions were found to be very promising for the development of a new diagnostic kit to detect HCV infection in human blood. Peptide purity was tested by RP-FPLC and the peptide identity was confirmed by amino acid analysis.

Hepacivirus↗