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Biomedical subjects

B B Das

Publications and source records attributed to B B Das.

At least 19 recordsLinked to original sources
PubMed2006

Apoptosis is induced in leishmanial cells by a novel protein kinase inhibitor withaferin A and is facilitated by apoptotic topoisomerase I-DNA complex.

Protein kinase C (PKC) is an important constituent of the signaling pathways involved in apoptosis. We report here that like staurosporine, withaferin A is a potent inhibitor of PKC. In Leishmania donovani, the inhibition of PKC by withaferin A causes depolarization of DeltaPsim and generates ROS inside cells. Loss of DeltaPsim leads to the release of cytochrome c into the cytosol and subsequently activates caspase-like proteases and oligonucleosomal DNA cleavage. Moreover, in treated cells, oxidative DNA lesions facilitate the stabilization of topoisomerase I-mediated cleavable complexes, which also contribute to DNA fragmentation. However, withaferin A and staurosporine cannot induce cleavable complex formation in vitro with recombinant topoisomerase I nor with nuclear extracts from control cells. Taken together, our results indicate that inhibition of PKC by withaferin A is a central event for the induction of apoptosis and that the stabilization of topoisomerase I-DNA complex is necessary to amplify apoptotic process.

Animals↗
PubMed2005

Amylopectinosis disease isolated to the heart with normal glycogen branching enzyme activity and gene sequence.

We report a 17-month-old female patient with a rare cause of cardiomyopathy secondary to accumulation of amylopectin-like material (fibrillar glycogen) isolated to the heart. Evidence of amylopectinosis isolated to cardiac myocytes in this patient was demonstrated by histology and electron microscopy. Glycogen content, glycogen branching enzyme (GBE) activity, as well as phosphofructokinase enzyme activities measured in liver, skeletal muscle, fibroblasts and ex-transplanted heart tissue were all in the normal to lower normal ranges. Normal skeletal muscle and liver tissue histology and GBE activity, normal GBE activity in skin fibroblasts, plus normal GBE gene sequence in this patient exclude the classical branching enzyme deficiency (type IV GSD). We believe that this is an as yet uncharacterized and novel phenotype of GSD associated with cardiomyopathy, in which there is an imbalance in the regulation of glycogen metabolism limited to the heart.

1,4-alpha-Glucan Branching Enzyme↗
PubMed2004

Camptothecin induced mitochondrial dysfunction leading to programmed cell death in unicellular hemoflagellate Leishmania donovani.

The parasites of the order kinetoplastidae including Leishmania spp. emerge from most ancient phylogenic branches of unicellular eukaryotic lineages. In their life cycle, topoisomerase I plays a significant role in carrying out vital cellular processes. Camptothecin (CPT), an inhibitor of DNA topoisomerase I, induces programmed cell death (PCD) both in the amastigotes and promastigotes form of L. donovani parasites. CPT-induced cellular dysfunction in L. donovani promastigotes is characterized by several cytoplasmic and nuclear features of apoptosis. CPT inhibits cellular respiration that results in mitochondrial hyperpolarization taking place by oligomycin-sensitive F0-F1 ATPase-like protein in leishmanial cells. During the early phase of activation, there is an increase in reactive oxygen species (ROS) inside cells, which causes subsequent elevation in the level of lipid peroxidation and decrease in reducing equivalents like GSH. Endogenous ROS formation and lipid peroxidation cause eventual loss of mitochondrial membrane potential. Furthermore, cytochrome c is released into the cytosol in a manner independent of involvement of CED3/CPP32 group of proteases and unlike mammalian cells it is insensitive to cyclosporin A. These events are followed by activation of both CED3/CPP32 and ICE group of proteases in PCD of Leishmania. Taken together, our study indicates that different biochemical events leading to apoptosis in leishmanial cells provide information that could be exploited to develop newer potential therapeutic targets.

Animals↗
PubMed2003

Neonatal aortic arch thrombosis masquerading as coarctation of the aorta.

We report two neonates with thrombosis of the aortic arch and isthmus diagnosed by echocardiography. Neonatal transient protein C deficiency was present in one patient and the other patient had severe perinatal asphyxia. Both patients presented with markedly reduced left ventricular function and severe aortic obstruction. In one infant, the thrombus was successfully removed surgically, and the second infant died due to serious complications of perinatal asphyxia.

Aorta, Thoracic↗
PubMed2002

Berry syndrome with trisomy 13.

We report on 2-day-old neonate with trisomy 13 with coexistent distal aortopulmonary septal defect, aortic origin of the right pulmonary artery, interrupted aortic arch, intact ventricular septum, and a patent ductus arteriosus diagnosed by two-dimensional and color Doppler echocardiography. Review of the literature reveals that this patient is the 24th reported case of Berry syndrome and the first case of this unusual combination of cardiovascular defects associated with trisomy 13 syndrome.

Aorta↗
PubMed2001

Serum-ascites albumin gradient: a predictor of esophageal varices with ascites.

Other investigators have found that in adults the Serum-Ascites Albumin Gradient (SAAG) to be 1.1 g/dl or greater in the presence of portal hypertension (PTHN) and less than that in its absence. We sought to determine the correlation between the level of SAAG and the complications of PTHN, manifested by the presence of esophageal varices in children with ascites. Our study included 26 patients with cirrhosis, diagnosed by liver biopsy and 14 patients with nephrotic syndrome (NS) diagnosed by established criteria. The SAAG was measured in all patients. The patients with cirrhosis had upper gastrointestinal (GI) endoscopy for assessment of esophageal varices (EV). We found that 84.6% (22 of 26) patients with cirrhosis had High SAAG (> or = 1.1 g/dl) and 15.4% (4 of 26) had low SAAG (< 1.1 g/dl) (p < 0.001). EV was found in 91% (20 of 22) patients with high SAAG and in 50% (2 of 4) patients with low SAAG (p = 0.013). The SAAG differentiated cirrhosis with EV from those without EV (sensitivity = 91%, specificity = 50%, positive predictive value = 91%, negative predictive value = 50% and efficacy = 85%). The high SAAG is a useful means to predict the presence of EV in children with ascites.

Adolescent↗
PubMed2000

Expedited human immunodeficiency virus testing of mothers and newborns with unknown HIV status at time of labor and delivery.

New York State introduced the first statewide program in the U.S. of expedited HIV testing (48-hour turn-around results) of mothers with unknown HIV status at the time of labor or delivery and their newborns on August 1, 1999. We evaluated the results of this program during its first 5 months at Lincoln Medical and Mental Health Center (Lincoln Hospital) in the Bronx, New York. There were 1,274 total live birth deliveries between August 1 and December 31, 1999. The HIV infection status of 539 mothers (42.3%) was unknown to medical providers in the labor-delivery suite, either due to lack of testing during the current pregnancy or unavailability of HIV documentation at the time of delivery. During labor and delivery, a total of 462 (85.7%) mothers with unknown HIV status consented to expedited HIV testing (Single Use Diagnostic System for HIV-1 antibody or SUDS). The newborns of 77 mothers (14.3%) who did not consent were tested immediately after birth. Seventeen tested positive for HIV-1 antibody by the SUDS test. The results of 10 of these infants (58.8%) were subsequently confirmed positive for HIV-1 antibody by Western Blot analysis. This new rapid HIV testing program facilitated early diagnosis of these previously unknown HIV-exposed infants, although the low positive predictive value of the test in our community calls for careful communication of these results pending confirmation.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Time-resolved optical diffusion tomographic image reconstruction in highly scattering turbid media.

The image of an object hidden in highly scattering media was reconstructed using a fast, noise-resistant algorithm newly applied to diffusion tomography. A pulsed light source producing scattered and transmitted light is examined at multiple times. Multiple source detector pairs around the medium are used to obtain data in many different directions. An inverse scattering algorithm with nonuniform regularization achieves rapid inversion convergence.

Journal Article↗
PubMed1992

Raman, fluorescence, and time-resolved light scattering as optical diagnostic techniques to separate diseased and normal biomedical media.

Studies of Raman scattering, fluorescence and time-resolved light scattering were conducted on cancer and normal biomedical media. Fourier transform Raman spectroscopic measurements were performed on human normal, benign and cancerous tissues from gynecological (GYN) tracts. A comparison of the intensity differences between various Raman modes as well as the number of Raman lines, enables one to distinguish normal GYN tissues from diseased tissues. Fluorescence spectroscopic measurements on human breast tissues show that the ratio of fluorescence intensity at 340 nm to that at 440 nm can be used to distinguish between cancerous and non-cancerous tissues. Separate studies on normal and cancerous breast cell lines show spectral differences. The measurements of back-scattered ultrafast laser pulses from human breast tissues show differences in the scattered pulse profiles for different tissues. These studies show that various optical techniques have the potential to be used in medical diagnostic applications.

Breast Neoplasms↗
PubMed1992

Outbreaks of egg drop syndrome due to EDS-76 virus in quail (Coturnix coturnix japonica).

Two outbreaks of the egg drop syndrome were observed in quail flocks maintained on a farm together with chickens. The decrease in egg production ranged from 10.6 per cent to 50.6 per cent, and the number of soft-shelled eggs increased with the decline in egg production. In both the outbreaks haemagglutination inhibiting antibodies to EDS-76 virus were detected. Fluorescent viral antigen specific to EDS-76 virus was also detected in the lining epithelial and glandular cells of the uterus.

Adenoviridae Infections↗
PubMed1975

Minimum blood concentration--a universal concept of anaesthetic potency.

Although brain concentration of anaesthetic agents is attractive as a method of expressing anaesthetic potency, both theoretical and practical considerations limit the usefulness of this index. Therefore, the MAC concept has been utilized to develop another expression of potency: the minimum blood concentration. This takes into account the blood/gas solubility coefficient, and the fact that at equilibrium the amount of anaesthetic agent present in brain is reflected in the blood concentration, and it is applicable to both parenteral and to inhalation anaesthetic agents.

Anesthetics↗