Biomedical subjects
Publications and source records attributed to S K Basu.
Ethanolic extract of Rungia repens aerials parts (300 and 600 mg/kg p.o) showed diuretic activity in rats. The acute toxicity, orally evaluated in mice, was found to be higher than 3000 mg/kg.
The study was designed to examine the binding of diclofenac sodium with bovine serum albumin (BSA) at different temperatures (20 degrees, 30 degrees and 40 degrees C), pH (6.4, 7.4 and 8.4) and ionic strengths (micro = 0.1, 0.2 and 0.3) by means of equilibrium dialysis method. The concentration of diclofenac sodium was maintained at wider range from 15 to 900 micromole/l and BSA concentration was maintained at 61.5 micromole/l. The data obtained were interpreted by nonlinear regression method using Graphpad prism software. The analysis showed that the interaction between diclofenac sodium with BSA results in two-site saturable binding. A decrease in association constant was observed with increasing temperature. The average standard free energy change (deltaGdegrees) value was -7.07 (site I) and -4.2 (site II) Kcal/mol. The standard enthalpy change (deltaHdegrees) and the standard entropy change (deltaSdegrees) were -7.8 Kcal/mole, -2.35 cal/mole (site I) and -7.4 Kcal/mole, -10.5 cal/mole (site II), respectively. The negative enthalpy change suggested the binding between diclofenac sodium and the binding sites of BSA were spontaneous and exothermic. The negative value of deltaHdegrees and deltaSdegrees indicated hydrogen bonding and van der Waal's force was the major mechanism for diclofenac sodium and BSA interaction. Increase in pH and ionic strength also caused decrease in association constant of diclofenac sodium and BSA binding.
Five cases of tumoral calcinosis were studied during the period of January-february 1999 in MIMER medical college, Talegaon, a rural place 35kms. from Pune. All the Five patients were females residing in nonendemic area for Dracunculosis. They were from 5th-6th decade. They were otherwise healthy and had normal serum calcium and phosphorus levels and no eosinophilia. All had large, hard subcutaneous lump around hip joint. The skin overlying the swelling was normal. Histologically all cases showed similar morphology, the lesions were composed of large and small deposits of calcium. The foreign-body giant cell reaction was seen in two cases. There were no eosinophils and lymphocytes. On multiple sectioning none of the cases revealed any evidence of dead or living parasite. Old and recent necrosis was absent. These cases are presented since the condition is comparatively rare and it appeared in crops in our Institute.
The potential for reductive dehalogenation of 2-CP in anaerobic batch cultures of fresh-water digested sludge under sulfidogenic and methanogenic conditions was investigated in the presence or absence of respective inhibitors: molybdate and BESA at various concentrations (0 to 10 mM). Triplicate cultures (50% vol/vol) were set-up under an atmosphere of 20% CO2 and 80% N2 in 160 ml serum bottles using anaerobic digester sludge and a mineral medium containing 0.1% yeast extract. The dehalogenation of 2-CP, as well as methanogenesis, occurred at the same rate in the presence or absence of sulphate. Sulphate reduction did not inhibit 2-CP degrading populations. The presence of BESA--a known inhibitor of methane producers partially inhibited methanogenesis and slowed 2-CP dehalogenation at even 1 mM concentration with phenol and acetate accumulation in the cultures. The accumulation was proportional to the increase in concentration of BESA in the system. Molybdate on the other hand completely inhibited both sulphate reduction and 2-CP dehalogenation at a concentration of 10 mM. The dehalogenation of 2-CP continued in the presence of 1 mM molybdate even after the cessation of sulphate reduction indicating that sulphate-reducing bacteria were not directly involved in the dehalogenation of 2-CP in this study. Inhibition of 2-CP dehalogenation and sulphate reduction along with accumulation of propionate at 10 mM molybdate in the cultures strongly suggests that the dehalogenation of 2-CP was more directly linked to syntrophic activity of the mixed culture compared to sulphate reduction.
The power of a child's speaking language never develops if he is deaf. Deafness persists if it is not detected early. Childhood deafness is either congenital or acquired. At birth, doctors or attendants can detect deafness by arousing the baby with sudden loud noise. At 4 months onwards mothers and doctors can detect deafness. The baby at this age can turn its head or eyes towards the source of the sound. By 12 months to 2 years of age it is very difficult to detect deafness. By the age of 3 years children again become co-operative and it becomes easier to detect deafness. Children should always be screened for deafness while being admitted to nursery classes. In school going age ie, 5 years onwards loss of tests can be employed to detect deafness. If a child is suspected be deaf, a general practitioner's responsibility is to refer him to an ENT specialist earlier. Any child whose mother believes her child is deaf should be given due attention. Otitis media with effusion, enlarged adenoid, chronic suppurative otitis media, recurrent otitis media are some diseases to be carefully looked into by the general practitioners. Now-a-days cochlear implantation surgery is gaining popularity to give hearing to deaf child. Moreover regular screening for deafness should be included school heath programme.
A 48-year-old Hindu housewife was presented with increased appetite, thirst, frequency of micturition, weakness, cramps in the legs, tingling in the fingers, decline in bladder-bowel control and dimness of vision. She was a patient of diabetes. On investigations and history, she was diagnosed as a case of type 2 diabetes transmitted in three generations as an autosomal dominant trait.
Explore the source record for details and available documents.
Twenty-three propane- and butane-utilizing bacteria were isolated from soil samples collected from oilfields. Three of them have been identified as Rhodococcus sp. IMT35, Pseudomonas sp. IMT37 and Pseudomonas sp. MT40. SDS-PAGE analysis of the membrane of Rhodococcus sp. IMT35 revealed the presence of at least four polypeptides induced by propane. Polyclonal antibody raised against a 58 kDa polypeptide from Rhodococcus sp. IMT35 specifically detected bacteria which were actively utilizing propane or butane. Immunoscreening of a genomic library in lambdagt11 with this antibody resulted in isolation of a clone containing a 4.9 kb EcoRI genomic DNA fragment. This 4.9 kb DNA fragment was found to hybridize specifically with organisms which could grow on propane or butane. This fragment could therefore be used as a probe for detection of such bacteria. A 2.3 kb fragment having an ORF encoding a polypeptide of 54 kDa was identified by screening a genomic library of Pseudomonas sp. IMT37 with this 4.9 kb EcoRI fragment. The sequence of the ORF (designated orf54) was found to be novel. Primer extension and S1 nuclease mapping showed that transcription of the ORF starts at base 283 and it had sequences upstream similar to that of a Pseudomonas promoter (-12, -24 type). Disruption of the ORF by a kanamycin ('kan') cassette prevented the organism from growing on any alkane but did not affect its ability to utilize the respective alkanols and acids, indicating that alcohol dehydrogenase and subsequent steps in the pathway remained unaltered. The mutants had no detectable level of butane monooxygenase activity. Therefore, the product of this gene plays a crucial role in the first step of the pathway and is an essential component of monooxygenase. The findings imply that this bacterium either employs a common genetic and metabolic route or at least shares the product of this gene for utilization of many alkanes.
An extremely rare case of bilateral antrochoanal polyp in an otherwise fit 12-year-old girl is reported. The antrochoanal polyps were removed by bilateral Caldwell-Luc operation. Histopathological examination showed them to be of benign inflammatory nature.
We investigated the intracellular route of Salmonella in macrophages to determine a plausible mechanism for their survival in phagocytes. Western blot analysis of isolated phagosomes using specific antibodies revealed that by 5 min after internalization dead Salmonella-containing phagosomes acquire transferrin receptors (a marker for early endosomes), whereas by 30 min the dead bacteria are found in vesicles carrying the late endosomal markers cation-dependent mannose 6-phosphate receptors, Rab7 and Rab9. In contrast, live Salmonella-containing phagosomes (LSP) retain a significant amount of Rab5 and transferrin receptor until 30 min, selectively deplete Rab7 and Rab9, and never acquire mannose 6-phosphate receptors even 90 min after internalization. Retention of Rab5 and Rab18 and selective depletion of Rab7 and Rab9 presumably enable the LSP to avoid transport to lysosomes through late endosomes. The presence of immature cathepsin D (48 kDa) and selective depletion of the vacuolar ATPase in LSP presumably contributes to the less acidic pH of LSP. In contrast, proteolytically processed cathepsin D (M(r) 17,000) was detected by 30 min on the dead Salmonella-containing phagosomes. Morphological analysis also revealed that after uptake by macrophages, the dead Salmonella are transported to lysosomes, whereas the live bacteria persist in compartments that avoid fusion with lysosomes, indicating that live Salmonella bypass the normal endocytic route targeted to lysosomes and mature in a specialized compartment.
We have shown that muramyl dipeptide (MDP) conjugated to a 10-mer polyguanylic acid (PolyG) is specifically internalized by macrophages through scavenger receptor (SCR)-mediated endocytosis. Macrophages activated by PolyG-MDP displayed about 20-fold higher cytotoxic activity against nonmacrophage tumor cells compared to that elicited by free MDP. The PolyG-MDP was found to trigger the secretion of higher levels of interleukin-6, interleukin-1alpha, TNF-alpha, and nitric oxide in comparison to free MDP. Addition of antibodies directed against IL-6 and TNF-alpha to macrophage culture completely abrogated the tumoricidal response of PolyG-MDP, indicating that these two cytokines are primarily responsible for bioefficacy. This general approach of PolyG as a vehicle may find wide application in the delivery of genes and antisense oligonucleotides to macrophages.
To understand intracellular trafficking modulations by live Salmonella, we investigated the characteristics of in vitro fusion between endosomes and phagosomes containing live (LSP) or dead Salmonella (DSP). We observed that fusion of both DSP and LSP were time, temperature and cytosol dependent. GTPgammaS and treatment of the phagosomes with Rab-GDI inhibited fusion, indicating involvement of Rab-GTPases. LSP were rich in rab5, alpha-SNAP, and NSF, while DSP mainly contained rab7. Fusion of endosomes with DSP was inhibited by ATP depletion, N-ethylmaleimide (NEM) treatment, and in NEM-sensitive factor (NSF)-depleted cytosol. In contrast, fusion of endosomes with LSP was not inhibited by ATP depletion or NEM treatment, and occurred in NSF-depleted cytosol. However, ATPgammaS inhibited both fusion events. Fusion of NEM-treated LSP with endosomes was abrogated in NSF- depleted cytosol and was restored by adding purified NSF, whereas no fusion occurred with NEM-treated DSP, indicating that NSF recruitment is dependent on continuous signals from live Salmonella. Binding of NSF with LSP required prior presence of rab5 on the phagosome. We have also shown that rab5 specifically binds with Sop E, a protein from Salmonella. Our results indicate that live Salmonella help binding of rab5 on the phagosomes, possibly activate the SNARE which leads to further recruitment of alpha-SNAP for subsequent binding with NSF to promote fusion of the LSP with early endosomes and inhibition of their transport to lysosomes.
Scavenger receptor (SR)-specific delivery by maleylation of a ubiquitous self-protein, Ig, to SR-bearing APCs results in self-limiting induction of autoimmune effects in vivo. Immunization with maleyl-Ig breaks T cell tolerance to self-Ig and causes hypergammaglobulinemia, with increases in spleen weight and cellularity. The majority of splenic B cells show an activated phenotype upon maleyl-Ig immunization, leading to large-scale conversion to a CD138+ phenotype and to significant increases in CD138-expressing splenic plasma cells. The polyclonal B cell activation, hypergammaglobulinemia, and autoreactive Ig-specific T cell responses decline over a 2-mo period postimmunization. Following adoptive transfer, T cells from maleyl-Ig-immune mice taken at 2 wk postimmunization can induce hypergammaglobulinemia in the recipients, but those taken at 10 wk postimmunization cannot. Hypergammaglobulinemia in the adoptive transfer recipients is also transient and is followed by an inability to respond to fresh maleyl-Ig immunization, suggesting that the autoreactive Ig-specific T cells are inactivated peripherally following disruption of tolerance. Thus, although autoreactive T cell responses to a ubiquitous self-Ag, Ig, are induced by SR-mediated delivery to professional APCs in vivo resulting in autoimmune pathophysiological effects, they are effectively and rapidly turned off by inactivation of these activated Ig-specific T cells in vivo.
We showed that muramyl dipeptide (MDP) conjugated to maleylated bovine serum albumin (MBSA) was internalized by macrophages (Mphi) through scavenger receptor (SCR)-mediated endocytosis, which leads to 50-fold higher cytotoxic activity against non-Mphi tumor cells compared with that elicited by free MDP-treated Mphi. The enhanced cytotoxic effect of MBSA-MDP was found to be a result of higher secretion of interleukin (IL)-1, IL-6, tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO) because the addition of antibodies directed against IL-1, IL-6, or TNF-alpha in combination with Mphi cultures totally abrogated the tumoricidal activity of MBSA-MDP. It is interesting to note that MBSA-MDP triggers the secretion of IL-12, whereas IL-10, a Mphi suppressor cytokine, could be detected only on free MDP treatment. The cytotoxic activity of MBSA-MDP was inhibited by indomethacin, indicating a regulatory role for prostaglandin E2 (PGE2). Efficient SCR-mediated intracellular delivery of MDP leading to elimination of cancer cells suggests the immunotherapeutic potential of this approach for treatment of neoplasia.
PURPOSE: To identify the growth conditions that would favor the development of a functional primary culture of pigmented rabbit corneal epithelial cells on a permeable support comparable to the intact tissue in bioelectric properties. METHODS: Rabbit corneal epithelial cells were isolated and cultured on precoated fibronectin/collagen/laminin permeable filters. Cells were grown at an air-interface with supplemented DMEM/F12 medium. Immunofluorescence and electron microscopy techniques, respectively, were used to confirm cornea-specific marker and morphological features. Permeability of the cell layers to model polar compounds was evaluated using 14C-mannitol, fluorescein isothiocyanate (FITC) and fluorescein isothiocyanate-dextran of 4,000 molecular weight (FD4). RESULTS: We found that culturing the epithelial cells at an air-interface (AIC) was a critical factor in the formation of tight cell layer and that omitting fetal bovine serum and keeping the concentration of epidermal growth factor at 1 ng/ml were equally important. Phenotypically, the AIC cell layers were found to express cornea-specific 64 kD keratin. Compared with cells cultured under the liquid-covered (LCC) condition, those cultured under AIC exhibited a significantly higher peak transepithelial electrical resistance (TEER) of up to 5 kOhm x cm2, a higher potential difference (PD) of up to 26 mV, and an estimated short-circuit current (Ieq) of 5 microA/cm2 after 7-8 days of culture. These values were comparable to those in the excised cornea. Consistent with the TEER, the AIC cell layers were 4-40 times less permeable to paracellular markers than their LCC counterpart. CONCLUSIONS: The AIC model merits further characterization of drug transport mechanisms as well as drug, formulation, physiological, and pathological factors influencing corneal epithelial drug transport.
The objective of this study was to assess the safety and efficacy of long-acting preparations of two commonly used calcium antagonists with particular reference to their effects on heart rate. Twenty patients with chronic stable angina were recruited to a double-blind, double-dummy crossover study of controlled-release diltiazem (diltiazem CR) versus sustained-release nifedipine (nifedipine SR) and underwent clinical assessment, symptom and adverse event reporting, and repeated treadmill exercise tests over a 10- to 11-week period. The main outcome measures were heart rate at rest and exercise, incidence of angina and nitroglycerin use, treadmill exercise performance (duration, time to angina, time to 1-mm ST-segment depression, heart rate at equivalent maximal exercise, and maximal ST-segment depression), and adverse events. Diltiazem CR significantly reduced heart rate at rest and equivalent exercise and incidence of angina and nitroglycerin use compared with nifedipine SR. Exercise duration time to angina and time to 1-mm ST-segment depression (but not maximal ST-segment depression) were all significantly improved by diltiazem CR. Diltiazem CR also caused significantly fewer adverse events than nifedipine SR. Calcium antagonists with negative chronotropic effects (eg, diltiazem CR) are safer and more efficacious as monotherapy in chronic stable angina than dihydropyridines (eg, nifedipine SR) even when a long-acting formulation of the latter is used.
Non-invasive delivery of peptide and protein drugs will soon become a reality. This is due partly to a better understanding of the endogenous transport mechanisms, including paracellular transport, endocytosis, and carrier-mediated transport of mucosal routes of peptide and protein drug administration. This paper focuses on work related to the elucidation of structure-function, intracellular trafficking, and regulation of the intestinal dipeptide transporter, PepT1.
Pathways for loading exogenous protein-derived peptides on MHC class I are thought to be present mainly in monocyte-lineage cells and to involve phagocytosis- or macropinocytosis-mediated antigenic leakage into either cytosol or extracellular milieu to give peptide access to MHC class I. We show that maleylation of OVA enhanced its presentation to an OVA-specific MHC class I-restricted T cell line by both macrophages and B cells. This enhanced presentation involved uptake through receptors of scavenger receptor (SR)-like ligand specificity, was TAP-1-independent, and was inhibited by low levels (2 mM) of ammonium chloride. No peptide loading of bystander APCs by maleylated (maleyl) OVA-pulsed macrophages was detected. Demaleylated maleyl-OVA showed enhanced MHC class I-restricted presentation through receptor-mediated uptake and remained highly sensitive to 2 mM ammonium chloride. However, if receptor binding of maleyl-OVA was inhibited by maleylated BSA, the residual presentation was relatively resistant to 2 mM ammonium chloride. Maleyl-OVA directly introduced into the cytosol via osmotic lysis of pinosomes was poorly presented, confirming that receptor-mediated presentation of exogenous maleyl-OVA was unlikely to involve a cytosolic pathway. Demaleylated maleyl-OVA was well presented as a cytosolic Ag, consistent with the dependence of cytosolic processing on protein ubiquitination. Thus, receptor-specific delivery of exogenous protein Ags to APCs can result in enhanced MHC class I-restricted presentation, suggesting that the exogenous pathway of peptide loading for MHC class I may be a constitutive property dependent mainly on the quantity of Ag taken up by APCs.