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U Banerjee

Publications and source records attributed to U Banerjee.

At least 19 recordsLinked to original sources
PubMed2005

Molecular epidemiology of clinical Cryptococcus neoformans strains from India.

Little is known about the molecular epidemiology of the human pathogenic fungus Cryptococcus neoformans in India, a country now in the midst of an epidemic of AIDS-related cryptococcosis. We studied 57 clinical isolates from several regions in India, of which 51 were C. neoformans var. grubii, 1 was C. neoformans var. neoformans, and 5 were C. neoformans var. gattii. This strain set included 18 additional sequential isolates from 14 patients. Strains were characterized phenotypically by measuring the polysaccharide capsule and by determining the MICs of standard antifungals. Molecular typing was performed by a PCR-based method using the minisatellite-specific core sequence (M13), by electrophoretic karyotyping, by restriction fragment length polymorphisms with the C. neoformans transposon 1 (TCN-1), and by URA5 DNA sequence analysis. Overall, Indian isolates were less heterogeneous than isolates from other regions and included a subset that clustered into one group based on URA5 DNA sequence analysis. In summary, our results demonstrate (i) differences in genetic diversity of C. neoformans isolates from India compared to isolates from other regions in the world; (ii) that DNA typing with the TCN-1 probe can adequately distinguish C. neoformans var. grubii strains; (iii) that TCN-1 sequences are absent in many C. neoformans var. gattii strains, supporting previous studies indicating that these strains have a limited geographical dispersal; and (iv) that human cryptococcal infection can be associated with microevolution of the infecting strain and by simultaneous coinfection with two distinct C. neoformans strains.

Adolescent↗
PubMed2004

Transthoracic lung aspiration in etiology of pneumonia.

Transthoracic lung aspiration was performed in 30 episodes of pneumonia in 27 children with malignancy on chemotherapy to assess etiology of pulmonary infections. Total of 22 organisms were isolated in 16/30 (53.3%) episodes. No acid fast bacilli or Pneumocystis carinii were seen. Organisms grown by blood culture correlated with that of lung puncture in 5 episodes, while throat culture and nasopharyngeal organisms correlated with that of lung puncture on one occasion each. Organisms isolated in 8/18 episodes (44.4%) of antemorten transthoracic aspiration included: Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Streptococcus faecalis and Diphtheroids. In 3/18 episodes, lung puncture results altered treatment and thus resulted in survival of the patients. Only one minor complication occurred in this study--pneumothorax that resolved spontaneously. Thus, transthoracic lung puncture is an useful and safe procedure in immunocompromised patients with pneumonia who do not respond to initial broad spectrum antibiotics.

Adolescent↗
PubMed2003

Fluconazole and itraconazole susceptibility of clinical isolates of Cryptococcus neoformans at a tertiary care centre in India: a need for care.

OBJECTIVES: In cryptococcosis, fluconazole is a standard prophylactic, therapeutic and maintenance option, particularly in the expanding HIV/AIDS group. However, its excessive use may lead to resistance in Cryptococcus neoformans. Variations in clinical response to fluconazole have already been noted elsewhere, and cases of post-therapy relapse are not uncommon. To assess azole antifungal susceptibility profiles of clinical cryptococcal isolates in India, the All India Institute of Medical Sciences (AIIMS) has recently initiated preliminary studies using NCCLS M27-A. MATERIALS AND METHODS: Twenty-eight randomly chosen AIIMS clinical isolates (spanning 1997-2000), 16 isolates from other institutions in North India, and six reference strains of C. neoformans were subjected to susceptibility testing to fluconazole and itraconazole. RESULTS: Among clinical isolates, susceptibilities to fluconazole and itraconazole were 84.1% and 93.2%, respectively. MICs for all clinical isolates were 0.25-32 mg/L for fluconazole and <0.03-0.25 mg/L for itraconazole. MIC50 and MIC90 values for fluconazole were 4 and 16 mg/L, respectively, and those for itraconazole were 0.032 and 0.125 mg/L, respectively. Out of 28 AIIMS clinical isolates, 22 had minimum fungicidal concentrations (MFCs) of fluconazole at 128 mg/L. Moderately high fluconazole MICs (16-32 mg/L) were observed in 16% of clinical isolates--probably the first such report from India. MIC/MFC ratios for fluconazole and itraconazole were 1:32 or more in 16 AIIMS clinical isolates, indicating possible azole tolerance. There was good agreement between MIC values obtained by the micro- and macro-broth dilution techniques of M27-A compared in this study. CONCLUSIONS: The observed MIC data warrant continued surveillance of susceptibility values of clinical cryptococcal isolates in India.

Confidence Intervals↗
PubMed2001

Cryptococcosis in India: the awakening of a giant?

The menace of cryptococcosis has assumed global proportions over the years. The tropical climate of the Indian subcontinent offers a suitable environment for Cryptococcus neoformans, and the onslaught of the acquired immune deficiency syndrome (AIDS) pandemic since the early 1990s has substantially influenced the situation. Coupled with that are the advances in laboratory diagnostic techniques that have made accurate diagnosis increasingly available. These factors together have led to a sharp increase in the number of reported cases of cryptococcosis. This review attempts to present an overview of the status of cryptococcosis in India from its first description to the most recent times. The disease has been reported from almost all parts of the country. C. neoformans var. neoformans is predominantly found in clinical samples, while C. n. var. gattii infection has also been reported. An organ commonly involved is the central nervous system, among others. Both immunocompromised and apparently immunocompetent patients have been affected. Laboratory diagnosis is mostly by conventional methods, while effective therapeutic options are limited. Early diagnosis followed by institution of specific therapy, where possible, has effectively reduced mortality. Awareness of the disease and maintenance of a high index of clinical suspicion is required. An integrated approach to patient management with active interaction between the clinicians and the laboratory personnel would be highly beneficial. The wide variety of presentations of the disease seen in India suggests the possibility of occurrence of strain variation which needs to be investigated fully. Introduction of routine testing of antifungal susceptibility of clinical isolates is also important in order to obtain baseline data on susceptibility patterns and to predict in advance any shift in those patterns in the population. To maintain a high standard in all such endeavours, the establishment of an external quality control system is desirable.

AIDS-Related Opportunistic Infections↗
PubMed2001

Redundant function of Runt Domain binding partners, Big brother and Brother, during Drosophila development.

The Core Binding Factor is a heterodimeric transcription factor complex in vertebrates that is composed of a DNA binding alpha-subunit and a non-DNA binding beta-subunit. The alpha-subunit is encoded by members of the Runt Domain family of proteins and the beta-subunit is encoded by the CBF beta gene. In Drosophila, two genes encoding alpha-subunits, runt and lozenge, and two genes encoding beta-subunits, Big brother and Brother, have been previously identified. Here, a sensitized genetic screen was used to isolate mutant alleles of the Big brother gene. Expression studies show that Big brother is a nuclear protein that co-localizes with both Lozenge and Runt in the eye imaginal disc. The nuclear localization and stability of Big brother protein is mediated through the formation of heterodimeric complexes between Big brother and either Lozenge or Runt. Big brother functions with Lozenge during cell fate specification in the eye, and is also required for the development of the embryonic PNS. ds-RNA-mediated genetic interference experiments show that Brother and Big brother are redundant and function together with Runt during segmentation of the embryo. These studies highlight a mechanism for transcriptional control by a Runt Domain protein and a redundant pair of partners in the specification of cell fate during development.

Animals↗
PubMed2000

Combinatorial signaling in the specification of unique cell fates.

How multifunctional signals combine to specify unique cell fates during pattern formation is not well understood. Here, we demonstrate that together with the transcription factor Lozenge, the nuclear effectors of the EGFR and Notch signaling pathways directly regulate D-Pax2 transcription in cone cells of the Drosophila eye disc. Moreover, the specificity of D-Pax2 expression can be altered upon genetic manipulation of these inputs. Thus, a relatively small number of temporally and spatially controlled signals received by a set of pluripotent cells can create the unique combinations of activated transcription factors required to regulate target genes and ultimately specify distinct cell fates within this group. We expect that similar mechanisms may specify pattern formation in vertebrate developmental systems that involve intercellular communication.

Animals↗
PubMed2000

Specification of Drosophila hematopoietic lineage by conserved transcription factors.

Two major classes of cells observed within the Drosophila hematopoietic repertoire are plasmatocytes/macrophages and crystal cells. The transcription factor Lz (Lozenge), which resembles human AML1 (acute myeloid leukemia- 1) protein, is necessary for the development of crystal cells during embryonic and larval hematopoiesis. Another transcription factor, Gcm (glial cells missing), has previously been shown to be required for plasmatocyte development. Misexpression of Gcm causes crystal cells to be transformed into plasmatocytes. The Drosophila GATA protein Srp (Serpent) is required for both Lz and Gcm expression and is necessary for the development of both classes of hemocytes, whereas Lz and Gcm are required in a lineage-specific manner. Given the similarities of Srp and Lz to mammalian GATA and AML1 proteins, observations in Drosophila are likely to have broad implications for understanding mammalian hematopoiesis and leukemias.

Animals↗
PubMed2000

Runt and Lozenge function in Drosophila development.

Runt and Lozenge (LZ) are members of the Runt domain family of transcriptional regulators and control a large number of developmental processes in Drosophila. Runt is a pair-rule gene, and is part of the network of genes that control pattern formation in the embryo. In the central nervous system, Runt function is necessary for the development of a subset of neurons. Runt is also a key regulator of sex determination, and directly controls Sex-lethal, a master gene that determines sex of the animal and controls dosage compensation. The LZ protein also participates in several key processes. LZ controls pre-patterning and cell-fate choices in the development of the visual system by regulating the expression of several fate-specifying transcription factors, and works in conjunction with general signaling pathways. LZ function is also required in hematopoiesis for the specification of a Drosophila blood cell lineage.

Animals↗
PubMed2000

Infections in acute leukemia: an analysis of 240 febrile episodes.

Infections are the major cause of morbidity and mortality in acute leukemia patients. Case records of 91 consecutive patients (AML-48, ALL-40, RAEB-t/AML-3) treated between January 1997 and July 1999 were studied to determine the type, frequency and severity of infections. Patients' median age was 36 y (range 6-66) and male to female ratio was 2.5:1. A total of 240 febrile episodes were recorded; of them, 162 were associated with neutropenia (absolute neutrophil count, ANC<500/mm3) and 78 were without neutropenia. Among the neutropenic episodes, an infectious etiology could be documented in 52%; the remainder (48%) were defined as isolated febrile episodes. Chest was the most common site of infection (35. 7%) followed by skin, soft tissue (13%), GIT (7%) and genitourinary tract (6%) infections in order of decreasing frequency. Microbiologically, gram positive organisms (staphylococcus aureus, coagulase negative staphylococcus, streptococcus, enterococcus) were the most common isolates (52.8%) followed by gram negative organisms (E. coli, klebsiella, pseudomonas) in 42.8% of isolates. Two patients had pulmonary tuberculosis and three patients had fungal infections (candida-2, aspergillus-1). Among non-neutropenic patients, infection could be documented in 36%; the remaining 64% were isolated febrile episodes. Gram negative infections were documented in 50%, gram positive in 30% and fungal infections (candida-4, aspergillus-1, mucormycosis-1) in 20% of them. A combination of third generation cephalosporin and an aminoglycoside were used in 79% of episodes initially; a combination of a newer penicillin and aminoglycoside (4.6%), double betalactums (4.1%), oral antibiotics (9.8%) and others were used in the remaining episodes. Fever resolved in 38% of episodes using the above combinations; in the remainder second line antibiotics (mainly vancomycin) and antifungals (amphotericin-B) were added empirically or depending on culture and sensitivity. In 52.5% of episodes fever resolved after addition of second line antibiotics and antifungals. 11 of 91 patients died of infectious complications in this study. There is a need for improvised diagnostic tests to detect infections early as well as for new therapies to overcome antimicrobial resistance.

Adolescent↗
PubMed2000

Species-specific prevalence of vaginal candidiasis among patients with diabetes mellitus and its relation to their glycaemic status.

OBJECTIVES: Non- C. albicans Candida species are increasingly being recognized as the cause of vulvo-vaginal candidiasis. These species are often less susceptible to antifungal agents. Patients with diabetes mellitus are at risk for vulvo-vaginal candidasis. We assessed the species-specific prevalence rate and risk of candidiasis in patients with diabetes mellitus and healthy controls. METHODS: Genital tract examination, direct microscopy and fungal cultures of discharge collected by high vaginal swab were undertaken among 78 consecutive patients with diabetes mellitus (mean (+/-sd) age 32+/-12 years and body mass index (BMI) 22.3+/-5.5kg/m(2)) and 88 age- and BMI-matched healthy females. Glycaemic control in the diabetic cohort was assessed by measuring total glycosylated haemoglobin. RESULTS: Candida species were isolated in 36 of 78 (46%) subjects with diabetes mellitus and in 21 of 88 (23%) healthy subjects (Chi-squared 9.11, P=0.0025). The predominant Candida species isolated in diabetics with vulvo-vaginal candidiasis were Candida glabrata (39%), C. albicans (26%) and C. tropicalis (17%). In contrast, in the control group, C. albicans, C. glabrata and C. hemulonii comprised 30% each, with none having C. tropicalis infection (for C. tropicalis: diabetic vs. control; 17% vs. nil, P=0. 05). Among the diabetic group, subjects with vulvo-vaginal candidiasis had significantly higher mean HbA1 when compared to those who had no such infection (12.8+/-2.6% vs. 9.7+/-1.7% respectively, P=0.001). The overall accuracy of direct microscopy and clinical examination for predicting vulvo-vaginal candidiasis was only 77% and 51%, respectively, in the diabetic group, and 83% and 65% in the control group. CONCLUSIONS: Patients with diabetes mellitus had a high prevalence rate (46%) of vulvo-vaginal candidiasis with relative risk of 2.45. The non- C. albicans species such as C. glabrata and C. tropicalis were the predominant species isolated among them. There seems to be a significant link between hyperglycaemia and vulvo-vaginal candidiasis.

Adult↗
PubMed2000

Polyherbal formulations with wide spectrum antimicrobial activity against reproductive tract infections and sexually transmitted pathogens.

PROBLEM: Recent reports indicate high incidence of genital infections, most of which are sexually transmitted. Although specific drugs and antibiotics are available for some, a safe spermicidal formulation with wide spectrum antimicrobial action would be a desirable addition to the presently available spermicides. METHODS: Formulations at different dilutions were tested in culture systems on standard strains and clinical isolates including some isolates resistant to drugs. The effect on (HSV)-2 and Chlamydia trachomatis was determined in vivo in progestin sensitized mice. The effect on HIV-1 was investigated in two standardized systems. RESULTS: Polyherbal cream inhibited the growth in culture of clinical isolates of Candida albicans, Candida krusei and Candida tropicalis. Both the polyherbal cream and the Praneem polyherbal pessary inhibited urinary tract Escherichia coli (including multidrug resistant strains), and Neisseria gonorrhoeae (including 2 strains resistant to penicillin). Both formulations manifested virucidal activity against HIV-1 at >2 and 50% dilutions (in two different test systems) on contact for 1-2 min. Intravaginal inoculation of the cream and the pessary suspensions before inoculation of the pathogen prevented lesions and vaginal transmission of HSV-2 and C. trachomatis in progestin sensitized mice. CONCLUSIONS: Polyherbal formulations have wide spectrum antibacterial, antifungal and antiviral effect against the tested sexually transmitted pathogens.

Animals↗
PubMed1999

The role of star in the production of an activated ligand for the EGF receptor signaling pathway.

The Star gene is a member of the EGFR signaling pathway which has diverse functions throughout Drosophila development. In order to investigate the protein distribution for Star, we have generated a polyclonal antibody. Here, we show that the Star protein is expressed perinuclearly in the early female germline and later is found in the oocyte cytoplasm. Star is expressed at low levels in other tissues. The subcellular localization of the protein has been determined when Star is overexpressed in the eye disc. Star is located in the nuclear and contiguous endoplasmic reticulum membranes. A functional assay in the wing disc demonstrates that Star expression can activate a nonprocessed membrane-bound form of the EGFR ligand Spitz and overexpression of Star in the eye disc promotes the formation of smaller Spitz proteins. Based on these results, we propose that the Star protein is likely to be involved in Spitz ligand processing.

Animals↗
PubMed1999

Role of the EGF receptor pathway in growth and patterning of the Drosophila wing through the regulation of vestigial.

Growth and patterning of the Drosophila wing disc depends on the coordinated expression of the key regulatory gene vestigial both in the Dorsal-Ventral (D/V) boundary cells and in the wing pouch. We propose that a short-range signal originating from the core of the D/V boundary cells is responsible for activating EGFR in a zone of organizing cells on the edges of the D/V boundary. Using loss-of-function mutations and ectopic expression studies, we show that EGFR signaling is essential for vestigial transcription in these cells and for making them competent to undergo subsequent vestigial-mediated proliferation within the wing pouch.

Animals↗
PubMed1998

Patterning an epidermal field: Drosophila lozenge, a member of the AML-1/Runt family of transcription factors, specifies olfactory sense organ type in a dose-dependent manner.

Sense organ development in the Drosophila antenna is initiated by the selection of a founder cell from an epidermal field. This cell is believed to recruit neighbours to form a cluster of cells which then divides to form a mature sense organ. In most systems so far studied, sense organ type appears to be specified by the identity of proneural genes involved in the selection of precursors. The regulation of proneural gene expression is, in turn, controlled by the prepatterning genes. In the antenna, the only known proneural function is that of atonal, a gene that is involved in founder cell choice in the sensilla coeloconica, and no prepatterning gene function has yet been demonstrated. In this study, we show that Lozenge, a protein which possesses a DNA binding domain similar to that of the Acute myeloid leukemia-1/Runt transcription factors, functions in a dose-dependent manner to specify the fate of the other two types of sense organs in the antenna: the sensilla trichoidea and the sensilla basiconica. Our results suggest that Lozenge may act on the epidermal field, resulting in founder cells acquiring specific cell fates that lead to the development of an appropriate type of sense organ.

Animals↗
PubMed1998

Disseminated candidosis in premature twins.

A unique case of disseminated candidosis in premature twins is presented where twin A developed disease soon after birth and died prior to the administration of antifungal therapy. On the other hand, twin B developed infection on the 26th day of birth but survived, though with sequelae (hydrocephalus), since he was promptly and accurately diagnosed and treated.

Candida albicans↗
PubMed1998

Lozenge is expressed in pluripotent precursor cells and patterns multiple cell types in the Drosophila eye through the control of cell-specific transcription factors.

In the developing Drosophila eye, individual cell fates are specified when general signaling mechanisms are interpreted in the context of cell-specific transcription factors. Lozenge, a Runt/AML1/CBFA1-like transcription factor, determines the fates of a number of neuronal and non-neuronal cells by regulating the expression of multiple fate-determining transcription factors. The Lozenge protein is expressed in the nuclei of the cells that it patterns and also in their undifferentiated precursors. An enhancer element located within the second intron of the lozenge gene is responsible for its eye-specific expression. Lozenge is not itself a cell-specific transcription factor, rather it prepatterns the eye disc by positioning cell-specific factors in their appropriate locations.

Animals↗