Biomedical subjects
Publications and source records attributed to D Gupta.
We report the case of a 15 years girl in whom avascular necrosis (AVN) of right femur head was the presenting feature of chronic stable phase of chronic myeloid leukemia (CML). To date, only three case of CML with AVN have been reported. So, in view of rarity of this condition, a similar case of CML presenting as AVN of femur head is being reported.
Guillain-Barre syndrome (GBS) is the commonest peripheral neuropathy causing ventilatory failure, and 10-30% patients may require respiratory support. Records of 11 adult patients of GBS in respiratory failure, admitted to the Respiratory Intensive Care Unit (RICU) of our institute for mechanical ventilation over a four-year period, were studied. Six patients received intravenous immunoglobulin. The median duration of mechanical ventilation was 38 days. Seven patients underwent tracheostomy. Four patients were ventilated for less than 2 weeks and 3 for more than 2 months each. Seven developed ventilator-associated pneumonia and/or sepsis. Three patients died in, and two shortly after discharge from RICU; all had systemic problems or complications of hospitalization.
BACKGROUND & OBJECTIVES: Early onset pauciarticular disease with uveitis is distinctly uncommon in Indian children with juvenile rheumatoid arthritis (JRA). The occurrence of anti-histone antibodies (AHA) in serum is strongly associated with presence of uveitis. There is a paucity of information from India on the levels of AHA in patients of JRA. In this study, an attempt was made to evaluate the levels of IgG and IgM antibodies to histones in children with JRA in north India. METHODS: Serum samples of 148 children with JRA (84 boys, 64 girls) were collected. Clinical details including onset, symptoms and course of the disease in each patient were recorded. Detailed eye examination including slit lamp examination was done in all patients at presentation and yearly thereafter to rule out uveitis. The presence of antihistone IgG and IgM antibodies was studied by ELISA. Antinuclear antibodies (ANA) were measured by indirect immunofluorescence using HEP-2 cells as substrate at a screening dilution of 1:40. RESULTS: Of the 148 children, 54 had pauciarticular (12 early onset and 42 late onset), 64 polyarticular and 30 systemic onset disease respectively. ANA were present in two children. AHA were raised in 15 (10%) children, of whom 10 had IgM antibodies, 3 had IgG and 2 had both isotypes. None of the children with early onset pauciarticular disease had uveitis, ANA or AHA. INTERPRETATION & CONCLUSION: The low occurrence of AHA and uveitis in our subset of patients with JRA is in contrast to that reported from Western countries. The low occurrence is unlikely due to technical reasons as the antigen that has been used consistently showed significant binding to serum from patients with systemic lupus erythematosus (SLE). This is in accordance with the rarity of early onset pauciarticular disease and chronic uveitis in these patients. More studies from other parts of the country are required to validate this observation.
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PURPOSE: To determine the severity and extent of emphysema in heavy smokers by high-resolution CT (HRCT) and to correlate the findings with spirometric tests (STs) and symptomatology. MATERIAL AND METHODS: Fifty adult smokers with a mean age of 53 years with a smoking history of more than 30 pack years and normal chest radiographs underwent HRCT of the chest and ST (FEV1, FEV1/FVC, PEFR). Among these, 22 had symptoms of pulmonary disease and 28 were asymptomatic. Quantification of emphysema was done using a density mask program and the visual scoring method. The results were correlated with ST and symptomatology. RESULTS: 58% (29 out of 50) of the subjects had significant emphysema on HRCT. Eleven out of 15 with normal ST showed emphysema on HRCT while 2 with airflow obstruction on ST showed normal CT scores. 14% (4 out of 28) asymptomatic subjects had severe emphysema compared to 64% of symptomatic subjects. Emphysematous changes were predominantly seen in upper lung zones in 48% of the patients while in 52% it was distributed equally in both upper and lower zones. The number of pack years of smoking showed a positive correlation with CT scores. The correlation between HRCT scores and ST was statistically significant. CONCLUSION: A significant number of asymptomatic and clinically undiagnosed smokers tend to have significant emphysema. HRCT helps in early detection of disease and thus helps implementation of preventive measures.
Extracorporeal shock wave lithotripsy, a relatively new non-invasive method of treating salivary gland calculi, is rarely used in UK hospitals. We present a case of parotid duct calculus treated successfully by lithotripsy in a United Kingdom (UK) district General Hospital.
OBJECTIVES: To develop and evaluate a computer program for interpretation of spirometry. METHODOLOGY: The spirometry programme was constructed in Epi Info software using a previously defined algorithm for interpretation. The programme incorporated current American Thoracic Society guidelines on interpretation of spirometry and was based on regression equations for healthy North Indians previously derived by us. The programme was pretested for two months before being put to routine use. RESULTS: Use of this spirometry programme led to consistent interpretation of spirometry results. There was significant saving of time while preparing reports, without any additional expenditure. CONCLUSION: The use of such computer programmes accelerate the reporting of pulmonary function test results at little extra cost, and all interpretations are performed in a consistent fashion.
Six patients received mechanical ventilation for 8 episodes of myasthenic crisis in a two year period. Median duration of ventilation was 8 days. Only one patient required ventilation for more than three weeks and underwent tracheostomy. Atelectasis and pneumonia were the common ventilator associated complications observed, and these responded to therapy. Two patients underwent thymectomy after initial stabilization and while being ventilated. All patients recovered completely.
A young patient with right pulmonary agenesis is described. She presented with left pneumonitis and improved with antibiotic therapy. She additionally had absence of right thumb and reduced muscle mass over right side of face. The anomalies may have resulted from an antenatal insult around the fourth week of embryonic development.
Bacteria and their ubiquitous cell wall component peptidoglycan (PGN) activate the innate immune system of the host and induce the release of inflammatory molecules. TNF-alpha is one of the highest induced cytokines in macrophages stimulated with PGN; however, the regulation of tnf-alpha expression in PGN-activated cells is poorly understood. This study was done to identify some of the transcription factors that regulate the expression of the tnf-alpha gene in macrophages stimulated with PGN. Our results demonstrated that PGN-induced expression of human tnf-alpha gene is regulated by sequences proximal to -182 bp of the promoter. Mutations within the binding sites for cAMP response element, early growth response (Egr)-1, and kappaB3 significantly reduced this induction. The transcription factor c-Jun bound the cAMP response element site, Egr-1 bound the Egr-1 motif, and NF-kappaB p50 and p65 bound to the kappaB3 site on the tnf-alpha promoter. PGN rapidly induced transcription of egr-1 gene and this induction was significantly reduced by specific mutations within the serum response element-1 domain of the egr-1 promoter. PGN also induced phosphorylation and activation of Elk-1, a member of the Ets family of transcription factors. Elk-1 and serum response factor proteins bound the serum response element-1 domain on the egr-1 promoter, and PGN-induced expression of the egr-1 was inhibited by dominant-negative Elk-1. These results indicate that PGN induces activation of the transcription factors Egr-1 and Elk-1, and that PGN-induced expression of tnf-alpha is directly mediated through the transcription factors c-Jun, Egr-1, and NF-kappaB, and indirectly through the transcription factor Elk-1.
A search for cellular binding proteins for peptidoglycan (PGN), a CD14- and TLR2-dependent macrophage activator from Gram-positive bacteria, using PGN-affinity chromatography and N-terminal micro-sequencing, revealed that tubulin was a major PGN-binding protein in mouse macrophages. Tubulin also co-eluted with PGN from anti-PGN vancomycin affinity column and bound to PGN coupled to agarose. Tubulin-PGN binding was preferential under the conditions that promote tubulin polymerization, required macromolecular PGN, was competitively inhibited by soluble PGN and tubulin, did not require microtubule-associated proteins, and had an affinity of 100-150 nM. By contrast, binding of tubulin to lipopolysaccharide (LPS) had 2-3 times lower affinity, faster kinetics of binding, and showed positive cooperativity. PGN enhanced tubulin polymerization in the presence of 4 M glycerol, but in the absence of glycerol, both PGN and LPS decreased microtubule polymerization. These results indicate that tubulin is a major PGN-binding protein and that PGN modulates tubulin polymerization.
The hepatitis E virus (HEV) is the causative agent of hepatitis E, an acute form of viral hepatitis. The biology and pathogenesis of HEV remain poorly understood. We have used in vitro binding assays to show that the HEV ORF3 protein (pORF3) binds to a number of cellular signal transduction pathway proteins. This includes the protein tyrosine kinases Src, Hck, and Fyn, the p85alpha regulatory subunit of phosphatidylinositol 3-kinase, phospholipase Cgamma, and the adaptor protein Grb2. A yeast two-hybrid assay was used to further confirm the pORF3-Grb2 interaction. The binding involves a proline-rich region in pORF3 and the src homology 3 (SH3) domains in the cellular proteins. Competition assays and computer-assisted modeling was used to evaluate the binding surfaces and interaction energies of the pORF3.SH3 complex. In pORF3-expressing cells, pp60(src) was found to associate with an 80-kDa protein, but no activation of the Src kinase was observed in these cells. However, there was increased activity and nuclear localization of ERK in the pORF3-expressing cells. These studies suggest that pORF3 is a viral regulatory protein involved in the modulation of cell signaling. The ORF3 protein of HEV appears to be the first example of a SH3 domain-binding protein encoded by a virus that causes an acute and primarily self-limited infection.
The innate immune system recognizes microorganisms through a series of pattern recognition receptors that are highly conserved in evolution. Insects have a family of 12 peptidoglycan recognition proteins (PGRPs) that recognize peptidoglycan, a ubiquitous component of bacterial cell walls. We report cloning of three novel human PGRPs (PGRP-L, PGRP-Ialpha, and PGRP-Ibeta) that together with the previously cloned PGRP-S, define a new family of human pattern recognition molecules. PGRP-L, PGRP-Ialpha, and PGRP-Ibeta have 576, 341, and 373 amino acids coded by five, seven, and eight exons on chromosomes 19 and 1, and they all have two predicted transmembrane domains. All mammalian and insect PGRPs have at least three highly conserved C-terminal PGRP domains located either in the extracellular or in the cytoplasmic (or in both) portions of the molecules. PGRP-L is expressed in liver, PGRP-Ialpha and PGRP-Ibeta in esophagus (and to a lesser extent in tonsils and thymus), and PGRP-S in bone marrow (and to a lesser extent in neutrophils and fetal liver). All four human PGRPs bind peptidoglycan and Gram-positive bacteria. Thus, these PGRPs may play a role in recognition of bacteria in these organs.
Multiple myeloma (MM) remains incurable, with a median survival of 3 to 4 years. This study shows direct effects of vascular endothelial growth factor (VEGF) upon MM and plasma cell leukemia (PCL) cells. The results indicate that VEGF triggers tumor cell proliferation via a protein kinase C (PKC)-independent Raf-1-MEK-extracellular signal-regulated protein kinase pathway, and migration via a PKC-dependent pathway. These observations provide the framework for novel therapeutic strategies targeting VEGF signaling cascades in MM.
The antiangiogenic activity of thalidomide (Thal), coupled with an increase in bone marrow angiogenesis in multiple myeloma (MM), provided the rationale for the use of Thal in MM. Previously, the direct anti-MM activity of Thal and its analogues (immunomodulatory drugs, IMiDs) on MM cells was demonstrated, suggesting multiple mechanisms of action. In this study, the potential immunomodulatory effects of Thal/IMiDs in MM were examined. It was demonstrated that Thal/IMiDs do not induce T-cell proliferation alone but act as costimulators to trigger proliferation of anti-CD3-stimulated T cells from patients with MM, accompanied by an increase in interferon-gamma and IL-2 secretion. However, an increase in autologous T-cell killing of patient MM cells could not be demonstrated. A role for natural killer (NK)- and LAK-cell-mediated killing is suggested because IL-2-primed peripheral blood mononuclear cells (PBMCs) treated with Thal/IMiDs demonstrated significantly increased lysis of MM cell lines. Cold target inhibition assays suggested NK- rather than LAK-cell-mediated killing. Furthermore, this killing was not major histocompatibility complex-class restricted, and the depletion of CD56(+) cells blocked the drug-induced MM cell lysis. It was significant that increased killing of patient MM cells by autologous PBMCs treated with Thal/IMiDs was also observed. Although the in vivo relevance of NK-cell-mediated MM cell killing is unknown, phenotypic analysis performed in MM patients receiving Thal therapy demonstrated an increase in CD3(-)CD56(+) cells in patients responding to therapy. Thus in vitro and in vivo data support the hypothesis that Thal may mediate its anti-MM effect, at least in part, by modulating NK cell number and function.
Hepatitis E virus (HEV) is the major cause of acute epidemic and sporadic hepatitis in the developing world. It is a positive-strand RNA virus with a genome length of about 7.2 kb. The replication mechanism of this virus is virtually unexplored. Identification of the regulatory elements involved in initiation of replication may help in designing specific inhibitors for therapy. In the positive-stranded RNA viruses the initiation of replication requires interaction of the 3' end of genome with its RNA-dependent RNA polymerase (RdRp) and possibly host-derived cofactors for synthesis of the minus-strand replicative intermediate. Secondary structure prediction of the conserved 3' end of the infectious HEV genome was carried out to identify possible stem-loop structures necessary for RNA-protein interaction and the model was confirmed by structure probing experiments. Electrophoretic mobility-shift assays showed specific binding of purified and refolded recombinant HEV RdRp protein to the 3' end of its RNA genome containing the poly(A) stretch. Mutations at the 3' end, in which the stem-loop structures were partially or completely destroyed or recreated revealed that the two stem-loop structures SL1 and SL2 at the 3' end and the poly(A) stretch are necessary for this binding. The interacting nucleotides in such an interaction were further identified by generating footprints of the complex by Pb(II)-induced hydrolysis. This specific binding of viral RdRp to the 3' end of HEV RNA directs the synthesis of complementary-strand RNA and thus such a binding domain might assume the role of a possible cis-acting element as a potential site for the initiation of replication.
MD-2 is associated with Toll-like receptor 4 (TLR4) on the cell surface and enables TLR4 to respond to LPS. We tested whether MD-2 enhances or enables the responses of both TLR2 and TLR4 to Gram-negative and Gram-positive bacteria and their components. TLR2 without MD-2 did not efficiently respond to highly purified LPS and LPS partial structures. MD-2 enabled TLR2 to respond to nonactivating protein-free LPS, LPS mutants, or lipid A and enhanced TLR2-mediated responses to both Gram-negative and Gram-positive bacteria and their LPS, peptidoglycan, and lipoteichoic acid components. MD-2 enabled TLR4 to respond to a wide variety of LPS partial structures, Gram-negative bacteria, and Gram-positive lipoteichoic acid, but not to Gram-positive bacteria, peptidoglycan, and lipopeptide. MD-2 physically associated with TLR2, but this association was weaker than with TLR4. MD-2 enhanced expression of both TLR2 and TLR4, and TLR2 and TLR4 enhanced expression of MD-2. Thus, MD-2 enables both TLR4 and TLR2 to respond with high sensitivity to a broad range of LPS structures and to lipoteichoic acid, and, moreover, MD-2 enhances the responses of TLR2 to Gram-positive bacteria and peptidoglycan, to which the TLR4-MD-2 complex is unresponsive.
Patients with tetralogy of Fallot were studied with a prespecified angiographic protocol aimed to delineate the types and incidence of coronary artery anomalies and to look for any correlation with other abnormalities detected by simultaneous detailed angiography. The incidence of coronary anomalies was found to be 7.0%; no association was found with these anomalies with any of the other abnormalities detected.