Search PubMed⌕ Search

Biomedical subjects

Ashok Kumar

Publications and source records attributed to Ashok Kumar.

At least 109 records · Page 6Linked to original sources

Electro-deposit polyaniline on carbon electrode for voltammetric detection of lipase.

Normally, the pancreatic digestive enzymes are created and carried into the duodenum in an inactive form. During pancreatitis attacks, these enzymes are inhibited from reaching the duodenum, become activated while still in the pancreas, and begin to autodigest and destroy the pancreas. In order to accurately detect lipase within seconds, a square wave technique was explored without immobilizing enzyme and any other biomolecules over the electrode surface. The cyclic voltammetric (CV) technique was used to coat a carbon electrode with a thin layer of polyaniline. This modified electrode proved to be highly sensitive and specific to detect lipase between 0 and 225 IU/L, which is well within the normal physiological range. The consistency and reliability of this technique proved to be a very formidable detector of lipase present in abnormal quantities due to pancreatitis and other pathological disorders. The interference test has been performed to detect the lipase in the presence of amylase 50, 100, and 150 IU/L to understand the interference phenomenon with lipase detection. There is no significant effect of the amylase concentration over lipase detection resulting from using a modified carbon electrode. The response time of the modified carbon electrode is approximately 5s and the electrode has shown to be stable for 4 weeks at room temperature without special storage condition.

Adsorption↗

New organotin(IV) ascorbates: synthesis, spectral characterization, biological and potentiometric studies.

New organotin(IV) ascorbates of the general formulae R(3)Sn(HAsc) (where R = Me , n-Pr, n-Bu and Ph) and R(2)Sn(Asc) (where R = n-Bu and Ph) have been synthesized by the reaction of R(n)SnCl(4-n) (where n = 2 or 3) with monosodium-l-ascorbate. The bonding and coordination behaviour in these complexes are discussed on the basis of UV-Vis, IR, Far-IR, (1)H and (13)C NMR, and (119)Sn Mossbauer spectroscopic studies. L-Ascorbic acid acts as a monoanionic bidentate ligand in R(3)Sn(HAsc) coordinating through O(1) and O(3). The Mossbauer studies together with IR and NMR studies suggest that for these polymeric derivatives, the polyhedron is trigonal bipyramidal around tin with three organic groups in the equatorial positions. In R(2)Sn(Asc), L-ascorbic acid acts as dianionic tetradentate ligand and a polymeric structure with octahedral geometry around tin with trans organic groups has been tentatively proposed. The complexes have been assayed for their anti-inflammatory and cardiovascular activity. Ph(2)Sn(Asc) has been found to show the highest activity among the studied complexes. It is suggested on the basis of potentiometric studies of Me(2)Sn(IV) and Me(3)Sn(IV) systems with L-ascorbic acid that under physiological conditions (pH = 7.0) Me(2)Sn(HAsc)(OH) (approximately 60%), Me(2)Sn(OH)(2) (approximately 40%) and Me(3)Sn(HAsc) (approximately 60%), Me(3)Sn(OH) (approximately 40%), respectively, are existing, which may be responsible for their biological activities.

Animals↗

Spatial clustering of hemorrhages in probable cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is a common cause of symptomatic intracerebral hemorrhage (ICH), as well as small asymptomatic hemorrhage in the elderly. We used gradient-echo MRI to analyze spatial distribution of 321 hemorrhages in 59 patients with probable CAA-related ICH. Hemorrhagic lesions were found preferentially in the temporal (ratio of actual to expected hemorrhages = 1.37) and occipital lobes (ratio = 1.45, p < 0.0001). Within individuals, hemorrhages tended to cluster, regardless of lobe (p < 0.0001). Among subjects followed prospectively for recurrence, clustering of new symptomatic and asymptomatic hemorrhages was observed. These data suggest that regional differences within the brain play a role in the development of CAA-related hemorrhage.

Aged↗

Evaluation of chemopreventive action and antimutagenic effect of the standardized Panax ginseng extract, EFLA400, in Swiss albino mice.

In the present investigation the chemopreventive action and antimutagenic effects of a standardized Panax Ginseng extract (EFLA400, processed Panax ginseng extract containing a high titre of ginsenoside Rg3 (>3.0% w/w) known as Phoenix ginseng) in Swiss albino mice have been evaluated. The oral administration of EFLA400 at 1, 3 and 10 mg/kg body weight at pre, peri and post-initiational phases, showed significant reductions in the number, size and weight of the papillomas. A significant reduction in tumour incidence (71.41 +/- 6.73%, 72.19 +/- 4.54% and 70.46 +/- 0.38% at 1, 3 and 10 mg/kg body weight, respectively) was observed in animals in the EFLA400 treated group compared with 100% tumour incidence in the control group. The cumulative number of papillomas during an observation period of 16 weeks was significantly reduced in the EFLA400 treated group (24 +/- 0.94, 16 +/- 1.41 and 11 +/- 1.41 at 1, 3 and 10 mg/kg body weight, respectively). However, the average latent period was significantly increased from 10.81 +/- 0.1 weeks in the control group to 12.39 +/- 0.28 weeks in the treated group (10 mg/kg body weight). The average tumour weight was recorded as 128.55 +/- 8.48, 116.00 +/- 8.48 and 57.5 +/- 3.29 mg in 1, 3 and 10 mg/kg body weight EFLA400 treated groups respectively. Chromosomal aberrations and micronuclei induction was also evaluated in bone marrow cells. These genotoxicity end-points were compared with papilloma occurrence at the same dose levels of carcinogen and ginseng. In the EFLA400 treated groups significantly reduced frequencies of chromosomal aberrations and micronuclei induced by DMBA and croton oil were observed. However, the maximum decrease in the frequencies of chromosomal aberrations and micronuclei were recorded in the 10 mg/kg body weight EFLA400 treated group than that of the 1 and 3 mg/kg body weight EFLA400 treated animals. The results from the present study suggest the dose dependent effectiveness of EFLA400 in chemoprevention and antimutagenicity in Swiss albino mice.

9,10-Dimethyl-1,2-benzanthracene↗

Type IV-A choledochal cysts: a challenge.

BACKGROUND/PURPOSE: Type IV-A choledochal cysts are characterized by congenital cystic dilatation of the biliary tree extending to involve the intrahepatic biliary channels also. A single-center experience of the management of type IV-A choledochal cysts is presented. METHODS: Thirty-five out of 105 (33%) patients with choledochal cysts, who underwent surgery at a tertiary care center in northern India from January 1989 to December 2002, were found to have a type IV-A (Todani's classification) cyst. The mean age of the patients was 24 years (range, 3 months to 60 years); 17 patients in the group were adults and 22 were females. Presenting features were abdominal pain, jaundice, cholangitis, and abdominal lump, in various combinations. RESULTS: Excision of the extrahepatic part of the cyst and a wide bilio-enteric anastomosis was achieved in 32 (91%) patients, while internal drainage of the cyst was necessitated in 3 patients, for technical reasons: collaterals due to portal hypertension (1 patient) and dense adhesions (2 patients). Six (17%) patients developed postoperative complications: 3 had bilio-enteric anastomosis leaks, with 2 requiring a percutaneous proximal biliary diversion; 2 had intraabdominal bleeds requiring re-exploration, and 1 had external pancreatic fistula that closed spontaneously. Follow-up information was available for 28 (80%) patients. Mean duration of follow up was 25 months (median, 12 months; range, 6 months to 9 years). Three patients required re-operation, for anastomotic stricture (n = 2) and hepatolithiasis and recurrent cholangitis (n = 1) during follow up. CONCLUSIONS: Excision of the extrahepatic part of the cyst and drainage of the intrahepatic part by a wide hilar or subhilar anastomosis gave satisfactory results in the majority of patients with type IV-A choledochal cysts. Close long-term follow up of these patients is essential, because they are likely to present with complications related to the residual intrahepatic part of the disease.

Adolescent↗

"Ambulatory PCNL" (tubeless PCNL under regional anesthesia) -- a preliminary report of 10 cases.

AIM: We report the technique, safety, outcome and efficacy of "tubeless percutaneous nephrolithotomy (PCNL) performed under regional anesthesia" in selected cases. METHODS: Patients satisfying the entry criteria for the regional block (spinal low-dose anesthesia with low-dose Bupivacaine plus Fentanyl) and tubeless procedure were subjected to a tubeless spinal PCNL The patients were followed up the next day for an ultrasonography and an x-ray of the KUB region. RESULTS: All the ten patients were discharged uneventfully the next day (mean hospital stay-40 h). No blood transfusion and postoperative analgesics (mean post op visual analogue pain score was 2.4) were required. The mean time to return of S(1) sensation, motor block and walking were 183,118 and 196.6 min respectively. There was complete stone clearance in all the cases with a mean collection of 14.5 cc was seen on the post op ultrasound. CONCLUSIONS: The present cases were reported to highlight that in a select group of patients tubeless PCNL under regional block is technically feasible and viable option. Regional block has the advantage of avoidance of general anesthesia and anaphylaxis due to use of multiple drugs. Tubeless PCNL has the advantage of avoidance of nephrostomy tube related postoperative pain discomfort and urosepsis. This synergistically (spinal + tubeless PCNL) speeds up the recovery, shortens the length of hospitalization and the analgesic requirement.

Adult↗

New diorganotin(IV) derivatives of 7-hydroxycoumarin (umbelliferone) and their adducts with 1,10-phenanthroline.

New diorganotin(IV) derivatives of the general formula R2Sn(Umb)2 (where R = n-Bu, n-Oct and Ph; Umb = umbelliferone anion) have been synthesized either by the reaction of R2SnO with umbelliferone under azeotropic removal of water or by the reaction of R2SnCl2 with sodium salt of umbelliferone. Further, the adducts of the general formula R2Sn(Umb)2.phen (where R = n-Bu and n-Oct; phen = 1,10-phenanthroline) have also been synthesized by the interaction of R2Sn(Umb)2 with 1,10-phenanthroline. The bonding and coordination behavior in these derivatives are discussed on the basis of IR and 119Sn Mössbauer spectroscopic studies in solid state. Their coordination behavior in solution is discussed by the multinuclear (1H, 13C and 119Sn) NMR spectral studies. The Mössbauer and IR studies indicate that umbelliferone acts as a monoanionic bidentate ligand in R2Sn(Umb)2 coordinating through O(7) and O(1). A distorted octahedral geometry around tin has been proposed for R2Sn(Umb)2 as well as for R2Sn(Umb)2.phen in solid state. The newly synthesized derivatives have been tested for their anti-inflammatory and cardiovascular activities. The average LD50 value >1000 mg kg(-1) of these compounds indicates their safety margin.

Animals↗

Molecular cloning and characterization of beta-defensin cDNA expressed in distal ileum of buffalo (Bubalus bubalis).

Defensins play a prominent role in protection of various epithelial surfaces. In this study, we have cloned and characterized the mRNA from the distal ileum of Bubalus bubalis. Total RNA after isolation from ileal epithelium was reverse transcribed to synthesize cDNA using primers designed by taking conserved region of cattle enteric beta-defensin (EBD) mRNA, goat beta-defensin 2 (BD 2) and cattle lingual antimicrobial peptide (LAP) mRNA sequences. The PCR amplified cDNA of 254 bp was ligated to pDrive cloning vector and transformed into XL-blue strain of E coli. The sequence analysis indicated 29 nucleotide substitutions with reported cattle EBD mRNA sequence sharing 86.2% homology, 92.1% with cattle LAP, 81.6% with cattle tracheal antimicrobial peptide and 84.6% with goat BD 2. The deduced amino acid sequence encodes for a 64 amino acid precursor peptide. Both nucleotide and amino acid sequence homology shows that the cloned sequence is closer to cattle LAP.

Amino Acid Sequence↗

Inhibition of mechanosensitive cation channels inhibits myogenic differentiation by suppressing the expression of myogenic regulatory factors and caspase-3 activity.

Mechanosensitive cation channels (MSC) are ubiquitous in eukaryotic cell types. However, the physiological functions of MSC in several tissues remain in question. In this study we have investigated the role of MSC in skeletal myogenesis. Treatment of C2C12 myoblasts with gadolinium ions (MSC blocker) inhibited myotube formation and the myogenic index in differentiation medium (DM). The enzymatic activity of creatine kinase (CK) and the expression of myosin heavy chain-fast twitch (MyHCf) in C2C12 cultures were also blocked in response to gadolinium. Treatment of C2C12 myoblasts with gadolinium ions did not affect the expression of either cyclin A or cyclin D1 in DM. Other inhibitors of MSC such as streptomycin and GsTMx-4 also suppressed the expression of CK and MyHCf in C2C12 cultures. The inhibitory effect of gadolinium ions on myogenic differentiation was reversible and independent of myogenic cell type. Real-time-polymerase chain reaction analysis revealed that inhibition of MSC decreases the expression of myogenic transcription factors MyoD, myogenin, and Myf-5. Furthermore, the activity of skeletal alpha-actin promoter was suppressed on MSC blockade. Treatment of C2C12 myoblasts with gadolinium ions prevented differentiation-associated cell death and inhibited the cleavage of poly (ADP-ribose) polymerase and activation of caspase-3. On the other hand, delivery of active caspase-3 protein to C2C12 myoblasts reversed the inhibitory effect of gadolinium ions on myogenesis. Our data suggest that inhibition of MSC suppresses myogenic differentiation by inhibiting the caspase-3 activity and the expression of myogenic regulatory factors.

Animals↗

Extrahepatic portal venous obstruction and obstructive jaundice: approach to management.

BACKGROUND: Patients with long-standing extrahepatic portal venous obstruction (EHPVO) develop extensive collaterals in the hepatoduodenal ligament as a result of enlargement of the periportal veins. These patients are also prone to develop obstructive jaundice as a result of strictures and/or choledocholithiasis. Surgical management of obstructive jaundice in such patients becomes difficult in the presence of these collaterals. AIM: To review the approach to management of patients with EHPVO and obstructive jaundice. METHODS: Retrospective review of patients with EHPVO and obstructive jaundice requiring surgical and/or endoscopic management between 1992 and 2002. RESULTS: Thirteen patients (nine males, aged 12-50 years) with EHPVO and obstructive jaundice were evaluated. No patient had underlying cirrhosis or hepatocellular carcinoma. Five patients (group A) had biliary stricture; three (group B) had choledocholithiasis; and five (group C) had biliary stricture with choledocholithiasis. Primary surgical management was performed in group A (portosystemic shunt in four-strictures resolved in three; hepaticojejunostomy in one). In group B (n = 3) endoscopic stone extraction was successful in two patients. One patient underwent staged procedure (portosystemic shunt followed by biliary surgery). In group C, initial endoscopic management failed in four patients in whom it was attempted. All five patients thereafter underwent surgery (staged procedure, one; choledochoduodenostomy, one; devascularization, one; abandoned, two). Repeat postoperative endoscopic management was successful in two of the group C patients. Overall (group B and C), massive intraoperative hemorrhage occurred in three patients (one died). Postoperative hemorrhage occurred in one patient. CONCLUSION: In patients with EHPVO and obstructive jaundice, primary biliary tract surgery has significant morbidity and mortality. Endoscopic management should be the preferred modality. In patients with endoscopic failure, a staged procedure (portosystemic shunt followed by biliary surgery) should be preferred. Strictures alone may resolve after a portosystemic shunt. Endoscopic stenting may be required as an adjunct.

Adolescent↗

In-situ synthesis and performance of titanium oxide/poly(methyl methacrylate) nanocomposites.

Polymer nanocomposites have elicited extensive research efforts due to their potential to exhibit spectacular properties. They have immense potential and are befitting materials to serve as an ideal and futuristic alternative for varied applications. Poly(methyl methacrylate) (PMMA) and titanium oxide (TiO2) nanocomposites used in this study were fabricated by an in-situ free radical polymerization process. Three point bend tests were conducted with a modified universal microtribometer to evaluate fracture toughness. The results indicated that the stress intensity values increase as the concentration of titanium oxide increases up to 1 vol% and subsequently decrease at higher concentrations. Scanning electron microscopy (SEM) images of fracture surfaces afforded clues as to the possible deformation mechanism. Ultraviolet-visible spectroscopy (UV-vis) evaluated the degree of transparency of the nanocomposites. It was observed that samples became opaque as the concentration was increased beyond 0.01% volume fraction. X-ray diffraction characterized the TiO2 crystalline phase and Scherrer's equation was used to calculate the crystallite size. Among the concentrations considered the 3% volume fraction sample had the largest crystallite size. Finally, microhardness measurements further characterized the mechanical properties of the composites.

Crystallization↗

Beta2 glycoprotein 1 in Indian patients with SLE.

Forty-five patients with systemic lupus erythematosus (SLE) were investigated to evaluate the role of antiphospholipid antibodies in causation of thrombosis in Indians. The antiphospholipid antibodies studied included lupus anticoagulant (LAC), anticardiolipin antibodies (aCL), and anti-beta(2)-glycoprotein 1 (a beta(2)-GP1). Twenty-seven patients (60%) had clinical manifestations of antiphospholipid antibody syndrome. Nineteen patients (42.2%) had a history of thrombosis, and eight (17.7%) had a history of recurrent fetal loss. aBeta(2)-GP1 was (IgG) was positive in 23 (51.1%), aCL in 13 (28.8%), and LAC in four (8.8%). Of 19 patients with thrombosis, 14 (73.6%) were positive for abeta(2)-GP1, eight (42.1%) for aCL, and none of them was positive for LAC. Of the eight patients with recurrent fetal loss, two (25%) patients were positive for beta(2)-GP1, five (62.5%) for aCL, and one (12.5%) for LAC. Of 18 patients without any manifestations of antiphospholipid syndrome (APS), seven patients (38.8%) were positive for abeta(2)-GP1, and three (16.6%) for aCL and LAC each. It is concluded that presence of abeta(2)-GP1 increases the risk of thrombosis and therefore should be looked for in all cases of SLE to consider prophylactic antithrombotic therapy in these patients.

Adolescent↗

A report of a case: anesthetic management of a parturient with severe thrombotic stenosis of a mechanical aortic valve--an exercise in coordination of subspecialties.

The pregnant woman with valvular heart disease presents significant challenges to the obstetric, anesthesiology, and cardiology teams. Although successful outcomes for both mother and fetus are possible with coordinated medical care, the patient with a prosthetic valve who requires systemic anticoagulation provides a dilemma of insufficient anticoagulation leading to valve thrombosis versus the risks of maternal perinatal hemorrhage or fetal effects from oral or parenteral anticoagulants. This case report describes the peripartum management of a patient at 27 weeks' gestation with thrombus on a prosthetic aortic valve.

Adult↗

Association of leukocyte CR1 gene transcription with the disease severity and renal involvement in systemic lupus erythematosus.

The reduced level of complement receptor 1 (CR1) on erythrocytes is speculated as a key mechanism contributing to immune complex (IC) overload and exaggerated complement (C) activation in systemic lupus erythematosus (SLE). Comparatively, fewer studies documented lower levels of CR1 on leukocytes and glomerular podocytes in this disease. The decline in E-CR1 is largely believed as an acquired phenomenon caused due to the proteolytic cleavage of CR1 from erythrocyte membrane. The mechanism underlying reduced CR1 expression on nucleated cells is under constant investigation. Recently, reduced leukocytes CR1 gene transcription had been demonstrated in SLE and was suggested as the main cause of decline in leukocyte CR1 (L-CR1). The relationship of L-CR1 gene transcription with severity and pathophysiology of disease needs to be elucidated. We determined the levels of L-CR1 in 30 active SLE patients and compared with normal healthy controls (n = 30). Patients were categorized into two groups i.e., with nephritis (n = 14) or without nephritis (n = 16). The expression of L-CR1 at transcriptional level was correlated with the levels of serum CIC, C3 and anti dsDNA antibodies. The levels of L-CR1 transcription were significantly reduced in all SLE patients as compared to controls (P < 0.001). This decline in L-CR1 however, was more marked in patients with nephritis than those without nephritis. In addition, the serum levels of CIC, anti dsDNA antibodies were higher and the levels of serum C3 were lower than the normal range in the patients. The difference was much more marked in SLE patients with nephritis than those without nephritis. The levels of L-CR1 transcription correlated negatively with the levels of CIC and anti dsDNA antibodies and positively with serum C3 levels. Thus, between SLE patients with and without nephritis, we found significant difference in the levels of L-CR1 transcription (P < 0.01), CIC (P < 0.05), anti dsDNA antibodies (P < 0.01) and C3 (P < 0.01). Our findings suggest that L-CR1 is drastically reduced in patients with severe form of SLE, i.e., lupus nephritis. Determination of L-CR1 expression at transcriptional level in addition to disease hallmarks like C3, CIC and anti-dsDNA antibodies may facilitate the assessment of severity of SLE and discrimination between patients with or without renal involvement.

Adult↗

Continuous maxillary and mandibular nerve block for perioperative pain relief: the excision of a complicated pleomorphic adenoma.

A 68-yr-old hypertensive patient with ischemic heart disease and intractable atrial fibrillation with stable hemodynamics and poor chest compliance underwent pleomorphic adenoma of the parotid gland using regional anesthesia with continuous propofol sedation. Continuous maxillary and mandibular nerve blocks were performed and excision was performed with complete intraoperative and postoperative pain relief without compromising the patient's hemodynamic variables.

Adenoma, Pleomorphic↗

Inhibition of benzo(a)pyrene induced lung adenoma by panax ginseng extract, EFLA400, in Swiss albino mice.

In the present investigation the chemopreventive action of Panax ginseng extract, EFLA400, in Swiss albino mice has been evaluated. We used a 9-week medium term anticarcinogenicity test model of lung adenomas [Yun et al.1)]. Lung adenomas were induced by single subcutaneous injection in the subscapular region with 0.02 ml of benzo(a)pyrene (BP) (0.5 mg suspension in 1% aqueous gelatin) in newborn mice (less than 24 h old). Also chromosomal aberrations and micronuclei induction were evaluated in bone marrow cells. These genotoxicity end-points were compared with adenoma incidence at the same dose levels of BP and EFLA400. The oral administration of EFLA400 (10 mg/kg body weight) showed significant reduction in number of adenomas and weight of the lungs induced by BP. A significant reduction (p<0.001) in lung adenoma incidence in EFLA400-treated mice was observed as compared to the 68.3+/-2.96% lung adenoma incidence in BP-alone group. The inhibition rate was 72.05+/-1.36% in EFLA400-treated group with respect to the reference group (BP-alone group). However, tumor multiplicity was observed as 0.91+/-0.08 and 0.25+/-0.01 in BP alone and BP+EFLA400-treated groups respectively. In EFLA400-treated group significantly reduced frequencies of chromosomal aberrations and micronuclei induced by BP were observed. The results of the present investigation suggest the chemopreventive action and antimutagenic effect of EFLA400 in Swiss albino mice induced by BP in newborn mice.

Adenoma↗