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Biomedical subjects

M Goswami

Publications and source records attributed to M Goswami.

At least 19 recordsLinked to original sources
PubMed2006

Involvement of reactive oxygen species in the action of ciprofloxacin against Escherichia coli.

Ciprofloxacin is an important and commonly used member of the fluoroquinolone group of antibiotics. Ciprofloxacin inhibits DNA topoisomerase II and DNA topoisomerase IV activities, eventually leading to bacterial cell death. In addition, an increase of reactive oxygen species in the bacterial cells in response to ciprofloxacin has been shown. We investigated the role of reactive oxygen species in the antibacterial action of ciprofloxacin by studying the effects of different antioxidant compounds on ciprofloxacin susceptibility of Escherichia coli. Among the antioxidants checked, glutathione and ascorbic acid provided substantial protection against ciprofloxacin. The involvement of superoxide anion (O2-) and hydrogen peroxide (H2O2) in the antibacterial action of ciprofloxacin was analyzed using superoxide dismutase, catalase, and alkyl hydroperoxide reductase knockout strains of E. coli. The effects of multicopy sod genes on ciprofloxacin susceptibility of E. coli were also analyzed. On the basis of our results, we conclude that O2- and H2O2 may be involved in antibacterial action of ciprofloxacin. Our findings that glutathione gave protection against other fluoroquinolones and not against nonfluoroquinolone antibiotics imply that reactive oxygen species may have a similar role in the antibacterial action of all these fluoroquinolones and that glutathione-mediated protection is not a general phenomenon but specific to fluoroquinolones. These observations are of significance, as fluoroquinolones are important antibiotics with immense therapeutic value, and the effectiveness of treatment by these drugs may be affected by dietary intake and cellular levels of these antioxidants.

Anti-Infective Agents↗
PubMed2005

Microbial metabolism of 2-chlorophenol, phenol and rho-cresol by Rhodococcus erythropolis M1 in co-culture with Pseudomonas fluorescens P1.

Chlorophenolic waste most often contains phenol and rho-cresol along with chlorophenols. A Rhodococcus erythropolis strain M1 was isolated with the ability to degrade 2-chlorophenol, phenol and p-cresol (100 mgl(-1), each) in 18, 24 and 20 h, respectively, with negligible lag. However, Rhodococcus sp. characterized by low growth rate, pose a threat to be outgrown by bacteria occurring in natural habitats. In the present study, interaction of R. erythropolis M1 with another isolated bacteria generally encountered in activated sludge for water treatment like Pseudomonas fluorescens P1 was studied. 2-chlorophenol, phenol and p-cresol were selected as the substrates for the study. Viable cell counts showed competitive interaction between the species on 2-chlorophenol and phenol. Specific growth rate of pure culture of R. erythropolis M1 was higher than P. fluorescens P1 on 2-chlorophenol. However, in mixed culture, P. fluorescens P1 showed higher growth rate. Degradation of phenol showed higher growth rate of R. erythropolis M1 both in pure and in mixed culture form. Degradation of p-cresol had shown similar counts for both populations indicating neutral type of interaction. This observation was substantiated by detecting the growth rate, where both cultures had similar growth rate in pure and in the mixed culture form. Rate of 2-chlorophenol degradation was higher when R. erythropolis M1 was used as the pure culture as compared to the degradation rates observed with the P. fluorescens P1 or with the mixed culture. However, in case of phenol and p-cresol, degradation by the mixed culture had resulted in higher degradation rates as compared to the degradation of the substrates by both the axenic cultures.

Biodegradation, Environmental↗
PubMed2003

Isolation and characterization of a phospholipase C delta isoform from pea that is regulated by light in a tissue specific manner.

Phosphoinositide-specific phospholipases C (PLCs) play an important role in many cellular responses and are involved in the production of secondary messengers. We report the cloning and characterization of a cDNA encoding a PLC-delta from Pisum sativum (PsPLC). The amino acid sequence deduced from the cDNA sequence showed 75-80% identity to other plant PLCs and contained the characteristic X, Y and C2 domains. The genomic PLC clone from pea was also characterized and found to contain eight introns. The protein was expressed in Escherichia coli, but the recombinant product did not show any phosphoinositide (PI)- or phosphatidylinositol-4, 5-bisphosphate (PIP2)-specific activity, despite having all known residues required for such activity, and in spite of the fact that its C2 domain was shown to bind calcium. Under similar in vitro assay conditions the recombinant tobacco PLC used as a control showed calcium-dependent PI- and PIP2-specific activity. Though PsPLC did not show enzyme activity in vitro, and may represent an inactive form of PLC, such as those reported in some mammalian systems, analysis of the transcription of PsPLC showed that the gene is expressed in all pea tissues, and is regulated by light in a tissue-specific manner. Roots showed higher expression of PsPLC than shoots. A putative PsPLC promoter region (792 bp) was also cloned and found to contain root-specific and light-responsive cis elements, suggesting that this form of PLC may be involved in important functions in plants.

Amino Acid Sequence↗
PubMed2001

Regulation of MAP kinase by the BMP-4/TAK1 pathway in Xenopus ectoderm.

Bone morphogenetic protein-4 (BMP-4) induces epidermis and represses neural fate in Xenopus ectoderm. Our previous findings implicate p42 Erk MAP kinase (MAPK) in the response to neural induction. We have examined the effects of BMP-4 on MAPK activity in gastrula ectoderm. Expression of a dominant negative BMP-4 receptor resulted in a 4.5-fold elevation in MAPK activity in midgastrula ectoderm. MAPK activity was reduced in ectoderm expressing a constitutively active BMP-4 receptor, or ectoderm treated with BMP-4 protein in the presence or absence of cycloheximide. Overexpression of TAK1 led to a reduction in MAPK activity in early gastrula ectoderm. The inhibitory effects of TAK1 could be reversed by 1 microM SB 203580, a p38 inhibitor. Treatment of isolated ectoderm with SB 203580 led to expression of otx2, NCAM, and noggin. Western blot analyses indicated that the BMP-4 pathway does not activate JNKs in ectoderm. Our findings indicate that BMP-4 inhibits ectodermal MAPK activity through a TAK1/p38-type pathway. MAPK has been shown to inactivate Smad1. Thus, our results suggest that BMP-4 and MAPK pathways are mutually antagonistic in Xenopus ectoderm, and that interactions between these pathways may govern the choice between epidermal and neural fate.

Animals↗
PubMed1999

Health-related quality of life effects of modafinil for treatment of narcolepsy.

OBJECTIVE: To evaluate the burden of illness of narcolepsy and assess the health-related quality-of-life (HQL) effects of oral modafinil, a wake-promoting therapy for excessive daytime sleepiness associated with narcolepsy. METHODS: Subjects with narcolepsy enrolled in a nine-week, placebo-controlled, double-blind study and were randomized to placebo, modafinil 200 mg, or modafinil 400 mg. After the study, consenting subjects received modafinil in a 40-week open-label extension. A self-administered HQL questionnaire consisting of the 36-Item Short Form Health Survey (SF-36) and supplemental narcolepsy-specific scales was given to subjects at baseline, study endpoint, and several open-label timepoints. RESULTS: 481 subjects completed a baseline and double-blind endpoint HQL assessment. Compared to population norms, baseline HQL scores reflected substantial burden in vitality, social functioning, and performing usual activities. At study endpoint, subjects in the 400 mg modafinil group had significantly higher scores than placebo for 10 of the 17 HQL scales. The 400 mg modafinil group had more energy, fewer difficulties performing usual activities, fewer interferences with social activities, improved psychological well-being and higher productivity, attention and self-esteem compared to placebo subjects (p<.05). The positive treatment effects were sustained over the open-label extension. CONCLUSION: Modafinil significantly improves health-related quality of life in narcolepsy.

Adult↗
PubMed1998

RAPD analysis of Candida albicans strains recovered from different immunocompromised patients (ICP) reveals an apparently non-random infectivity of the strains.

The opportunistic imperfect fungus Candida albicans causing life-threatening infections in immunocompromised patients (ICP), especially in HIV-positive cases, is recognized to be one of the most important nosocomial pathogens in the recent decades. The extent of strain-to-strain variation within a species and its relationship to the ability of the organism to colonize or invade a specific group of patients or even a body site is, however, not well known. We have analysed 19 strains of C. albicans recovered from ICP at different locales and times, employing the RAPD technique. No two strains generated identical RAPD profiles with any of the 21 primers tested. Further, the UPGMA clustering of the strains seemingly reflected a certain relationship or nonrandomness in the infection of the patients with the strain of C. albicans vis-a-vis the immunocompromised status due to underlying disease such as diabetes, cancer, asthma and meningitis. These results may have a profound impact on the management of candidiasis, especially in the ICP.

Candida albicans↗
PubMed1998

Aspergillus fumigatus strains recovered from immunocompromised patients (ICP): subtyping of strains by RAPD analysis.

Invasive pulmonary aspergillosis in immunocompromised patients (ICP) is the second most frequent opportunistic fungal infection. The causative organism includes 16 species of Aspergillus, of which A. fumigatus dominates the ubiquitous incidence of invasive or allergic broncho-pulmonary aspergillosis (ABPA). The definitive diagnosis of invasive aspergillosis is difficult. We have analyzed 24 strains of A. fumigatus recovered from ICP using the RAPD technique. The profiles generated with the 20 primers tested were mostly unique. These results may have a profound impact on the management of aspergillosis, especially in the ICP.

Aspergillosis↗
PubMed1998

The influence of clinical symptoms on quality of life in patients with narcolepsy.

Quality of life is a multidimensional construct involving subjective well-being, health, and welfare. For the patient with narcolepsy, as for any patient with a chronic illness, clinical symptoms have a major impact on physical and psychosocial function and hence on quality of life. This article briefly reviews selected effects of narcolepsy and describes the results of studies undertaken by researchers at the Sleep-Wake Disorders Center of Montefiore Medical Center in New York City. The goal of these studies was to determine the social characteristics and perceived needs of patients and to document the prevalence of the clinical features of narcolepsy and their impact on quality of life. Using a combination of methodologies--mail survey, record review, and personal interviews--the researchers found that clinical symptoms of narcolepsy have a profound impact on the physical, mental, and social health of those affected with the disorder.

Adolescent↗
PubMed1998

Maternal knowledge on risk behavioural practices and it's association with diarrhoea in a rural community of West Bengal, India.

Knowledge of rural mothers related to five diarrhoeagenic risk behaviours, identified in an earlier study, was ascertained. A high proportion of mothers (67%-79%) had knowledge about risk of bottle feeding, non-use of soap for cleaning feeding containers, storage of drinking water in wide-mouthed vessels and indiscriminate disposal of children's faeces. However, only around 31% of mothers were aware about danger of using pond water for cleaning feeding containers. Risk behavioural practices were less amongst mothers who had knowledge about them. Risk of diarrhoea amongst children of mothers having risk practice without knowledge as compared to those who utilised their knowledge to avoid risk practice was found significantly higher (p < or = 0.005) except for bottle feeding (p = 0.330). The results of this study indicate that children can be protected significantly from diarrhoea if mothers' diarrhoeagenic behaviours can be altered through educational intervention.

Adult↗
PubMed1996

Effects of some psychotropic agents on cognitive functions in rats.

The effects of some psychotropic agents were evaluated on cognitive function in rats. Acute administration of antipsychotic agents chlorpromazine, haloperidol or pimozide-all inhibited the active avoidance response as elicited by pole climbing test-the least effect being seen with pimozide. The antianxiety benzodiazepines, lorazepam and alprazolam, also attenuated active avoidance learning with the latter showing lesser effects. Maze task performance was differentially affected by these psychotropic drugs with maze traversing time being increased significantly after all drug treatment, except alprazolam.

Animals↗
PubMed1995

Antinociceptive action of Azadirachta indica (neem) in mice: possible mechanisms involved.

Azadirachta indica (AI, Neem) was tested for analgesic potency in experimental pain models in mice. In the glacial acetic acid (GAA) induced writhing test, AI (10, 30 and 100 mg/kg) dose-dependently reduced both the incidence and the number of writhes. Similarly, AI, at the dose levels tested, also enhanced tail withdrawal latencies in the tail-flick test for nociception. In the interaction studies, pretreatment with the opioid antagonist, naloxone (1 mg/kg) and the central noradrenaline depleter, DSP-4 (50 mg/kg) attenuated AI analgesia by differential degrees in both experimental models, whereas, the serotonin synthesis inhibitor, PCPA (300 mg/kg) potentiated the same. These results suggest that both central and peripheral mechanisms and complex neural pathways, opioid and non-opioid, may be involved in AI induced analgesia.

Analgesics↗
PubMed1994

Fat and oil inhibit phosphine release from aluminium phosphide--its clinical implication.

Poisoning by suicidal or accidental ingestion of aluminium phosphide (AlP) is a frequent medical emergency seen all over the world. AlP, a grain fumigant and rodenticide, on exposure to moisture, liberates highly toxic gas, phosphine. The rapidly inhibits mitochondrial respiration and has cytotoxic action. No specific antidote is known against it till date and prognosis depends much on dose and time lag between AlP ingestion and the stomach wash in the hospital (critical period). Physicochemical properties of AlP and nonmiscibility of fat and water promoted us to study the effect of different fats and oils as possible antidotes to inhibit phosphine liberation. In vitro experiments revealed that vegetable oils and liquid paraffin were much more effective than butter and ghee in inhibiting release of phosphine from AlP. These findings may have significant clinical implication.

Aluminum Compounds↗