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Biomedical subjects

S Mukherjee

Publications and source records attributed to S Mukherjee.

At least 19 recordsLinked to original sources
PubMed1994

Motionally restricted tryptophan environments at the peptide-lipid interface of gramicidin channels.

The tryptophans in the gramicidin channel play a crucial role in the organization and function of the channel. The localization and dynamics of these tryptophans have been studied using fluorescence spectroscopy, especially utilizing environment-induced effects on the rates of solvent relaxation around these residues in membranes. When incorporated into model membranes of dioleoyl-sn-glycero-3-phosphocholine (DOPC), the tryptophans in the gramicidin channel exhibit a red edge excitation shift (REES) of 6 nm. In addition, fluorescence polarization shows both excitation and emission wavelength dependence. Fluorescence lifetime analysis shows a biexponential decay, corresponding to a short- and a long-lifetime component. The mean lifetime was found to be dependent on both excitation and emission wavelengths. Analysis of time-resolved emission spectra (TRES) shows a heterogeneous environment for the tryptophans consistent with the lifetime information. Taken together, these observations point out the motional restriction experienced by the tryptophans in the gramicidin channel. This is consistent with other studies in which such restrictions are thought to be imposed due to hydrogen bonding between the indole rings of the tryptophans and the neighboring lipid carbonyls. The significance of such organization in terms of functioning of the channel is brought out by the fact that substitution, photodamage, or chemical modification of these tryptophans is known to give rise to channels with conformation and reduced conductivity.

Gramicidin↗
PubMed1992

Identification of calcium-dependent phospholipid-binding proteins (annexins) from guinea pig alveolar type II cells.

A new group of calcium-regulating proteins, called annexins or Ca(++)-dependent phospholipid-binding proteins (PLBP), have been detected in different species, organs and cell types. In the present study, we have identified and quantitated PLBP from guinea pig lung, lavage fluid and alveolar type II cells to elucidate the possible role of PLBP in lung surfactant biogenesis and secretion. Lungs were lavaged and type II cells from lavaged lung were isolated by elastase digestion and purified by centrifugal elutriation. For the quantitative identification of PLBP, we performed ELISA assays and Western blot analysis by using an antiserum raised in guinea pigs against a pure rabbit lung 36 kDa PLBP. The lavage fluid, cytosol from lung and type II cells contained 784, 167 and 435 ng per mg protein, respectively, of PLBP. The SDS-PAGE electrophoretic pattern and Western blot confirmed that all lung samples have band corresponding to a 36 kDa protein. This indicates that both alveolar type II cells and lavage fluid have higher levels of PLBP than whole lung cytosol.

Animals↗
PubMed1992

Activation of distant replication origins in vivo by DNA looping as revealed by a novel mutant form of an initiator protein defective in cooperativity at a distance.

We have isolated mutants of the pi initiator protein of the plasmid R6K that are defective in DNA looping in vitro but retain their normal DNA binding affinity for the primary binding sites (iterons) at the gamma origin/enhancer. One such looping defective mutant called R6 was determined to be a proline to leucine change at position 46 near the N terminus of the pi protein. Using a set of genetic assays that discriminate between the activation of the gamma origin/enhancer from those of the distantly located alpha and beta origins, we show that the looping defective initiator protein fails to activate the alpha and beta origins but derepresses initiation from the normally silent gamma origin in vivo. The results conclusively prove that DNA looping is required to activate distant replication origins located at distances of up to 3 kb from the replication enhancer.

Autoradiography↗
PubMed1992

Pathogenicity of Sporotrichum pruninosum and Cladosporium oxysporum, isolated from the bronchial secretions of a patient, for laboratory mice.

In this study we have demonstrated the occurrence of Sporotrichum pruinosum and Cladosporium oxysporum in the bronchial secretions of a patient with a presumptive diagnosis of tuberculosis. This observation coupled with the ability of both fungi to cause infection and elicit tissue responses in experimentally infected mice supported a probable etiologic relationship with the patient which could not be confirmed in the absence of histologic evidence. In vitro some antimycotics were tested against S. pruinosum and C. oxysporum by the agar dilution method. Oxiconazole with a minimum inhibitory concentration of 0.1 micrograms/ml-1 after 72 h and amorolfine at a concentration of 0.001 micrograms/ml-1 after 72 h were the most active ones against S. pruinosum and C. oxysporum respectively. It is suggested that the isolation of S. pruinosum and C. oxysporum from patients with bronchopulmonary disorders should be viewed with caution. Clinical and laboratory evaluation of such patients should be done critically before arriving at a firm diagnosis.

Animals↗
PubMed1992

Bronchoesophageal fistula of tuberculous origin in a child.

Bronchoesophageal fistulas (BEF) are uncommon in children, the etiology being congenital or acquired. Acquired bronchial perforation of tuberculous origin is common in children with pulmonary tuberculosis but bronchoesophageal perforation secondary to tuberculosis and leading to a fistulous tract formation is rare. To date, there have only been 4 case reports of BEF of tuberculous origin in children. We present yet another case of an acquired BEF of tuberculous origin in a child who presented with a sudden onset of dysphagia and choking sensation.

Bronchial Fistula↗
PubMed1992

Comparison of negative symptoms in schizophrenic and poor outcome bipolar patients.

Using the Scale for the Assessment of Negative Symptoms (SANS), affective blunting, alogia, and attentional impairment were assessed in 30 manic patients with chronic impairment of inter-episode instrumental functioning and 85 chronic schizophrenic patients. The schizophrenic patients had markedly higher ratings on all three negative symptom dimensions. When negative symptoms were examined categorically, no manic patient was rated to show prominent affective flattening or alogia. This relative specificity may not apply to attentional impairment which was rated as prominent in 17% of the manic patients and in 55% of the schizophrenic patients.

Activities of Daily Living↗
PubMed1992

The antimicrobial effect of an iron-binding agent on Streptococcus mutans.

The antimicrobial activity of 2,2'-bipyridine, an iron-binding agent, was investigated by incorporating this agent into Scotchbond dental adhesive resin. The growth of Streptococcus mutans on the surface of resin, media and culture vessel was determined by optical density measurements. It was observed that 2,2'-bipyridine exhibited excellent antimicrobial properties.

2,2'-Dipyridyl↗
PubMed1992

Effects of physical stress on complete blood count and venous blood gas profile of individuals with sickle cell trait.

The association between sickle cell trait (SCT) and adverse effects of exercise has been controversial. While individuals with SCT are at higher risk of sudden death, the mechanism for this outcome remains to be elucidated. In order to shed light on this controversy, we have monitored venous blood count and blood gas parameter values in normal and SCT subjects during treadmill exercise. White and red blood cell counts and hemoglobin changed significantly over time in both the SCT and normal groups, with peak exercise values different from pre-exercise or post-exercise values. Red blood cell counts showed significant group-time interaction; increase in count during exercise was accentuated in SCT subjects. All blood gas parameters showed significant changes over time in both groups. O2 content was significantly higher in SCT than AA at all time intervals. O2 saturation, pO2 and CO binding to hemoglobin showed significant group-time interaction. Furthermore, O2 saturation for the combined groups was significantly greater at peak exercise and at rest than before exercise. It is possible that treadmill exercise causes microvascular shunting in SCT subjects, leading to a decrease in the peripheral utilization of oxygen.

Adult↗
PubMed1992

Painful sensory symptoms in neuroleptic-induced extrapyramidal syndromes.

OBJECTIVE: The authors tested the hypothesis that neuroleptic-induced extrapyramidal syndromes are associated with painful sensations objectively conforming to the characteristics of primary sensory symptoms as reported in idiopathic and postencephalitic parkinsonism. METHOD: The frequency of subjective painful sensory symptoms and their relation to neuroleptic-induced extrapyramidal syndromes were examined in a consecutive series of 107 psychiatric patients newly admitted to acute care units at a teaching hospital. Patients without illnesses or conditions likely to be associated with pain were included in the study if they had a diagnosis other than organic mental syndromes and were receiving psychotropic medications as prescribed by their treating physicians. Structured interviews with a modified version of the McGill Pain Questionnaire to assess sensory complaints and neurological examinations for neuroleptic-induced extrapyramidal syndromes (parkinsonism and akathisia) were conducted independently by two raters blind to each other's findings and patients' medication status. RESULTS: Fourteen (23%) of 60 patients receiving neuroleptics reported experiences of spontaneous pain subjectively attributed to pharmacological treatment, compared with only one (2%) of 47 patients receiving psychotropic medications other than neuroleptics. There was no difference between these two groups in subjective complaints of paresthesia (8% versus 9%). Twelve (55%) of the 22 patients with neuroleptic-induced extrapyramidal syndromes reported pain, compared with only two (5%) of the 38 patients who received neuroleptics but did not experience extrapyramidal syndromes. CONCLUSIONS: Although consonant with the study hypothesis, these results should be regarded as preliminary and interpreted conservatively in the light of the methodological limitations of the study.

Adult↗
PubMed1992

Symptomatic predictors of ECT response in medication-nonresponsive manic patients.

BACKGROUND: Relations between pretreatment symptom ratings and ECT outcome were examined in acute manic patients admitted at a state psychiatric center who were nonresponsive to medication. METHOD: One or 2 days after undergoing pretreatment clinical ratings, patients were randomly assigned to intensive pharmacotherapy, right unilateral ECT, left unilateral ECT, or bilateral ECT. Patients who failed to respond to any of the first three treatment conditions were assigned to crossover bilateral ECT. Patients who failed to respond to a primary treatment condition other than bilateral ECT but refused crossover bilateral ECT and those in whom ECT was terminated due to an organic brain syndrome were not considered for this study. No psychotropic drugs were prescribed for 4-7 days before, or during, the course of ECT. Of the 24 patients who entered the study, 18 patients completed the protocol. Based on independent clinical assessments by two research psychiatrists, a favorable treatment response was defined as a complete recovery from manic episode that was sustained for 1 week during which no psychotropic medications were prescribed. RESULTS: ECT nonresponders were significantly more angry, irritable, and suspicious than ECT responders. Severity of mania and depression ratings at baseline were not related to ECT response. CONCLUSION: Symptoms associated with poor response to ECT may overlap with those that have been reported to predict nonresponse to treatment with lithium. Our evidence also may support the view that differential symptom patterns may predict treatment outcomes to ECT and carbamazepine, respectively, in manic patients who do not respond to treatment with lithium or neuroleptics.

Adult↗
PubMed1992

Diagnostic evaluation of ascitic adenosine deaminase activity in tubercular peritonitis.

Activity of adenosine deaminase (ADA) in serum and peritoneal fluid was studied prospectively in 24 aetiologically proved cases of ascites and 10 age-matched controls. Patients were divided into 3 groups according to causes of ascites, viz. malignant ascites (11), tubercular peritonitis (7) and cirrhosis of liver (6). Serum ADA values and peritoneal: serum ADA ratio did not show any consistent pattern in any group. But in patients with tubercular peritonitis ADA activity in ascitic fluid was significantly higher (P < .001) than in the other groups. An ascitic ADA level of 30 units/L had a sensitivity of 100% and specificity of 94.1% for tubercular peritonitis. These findings suggest that the ascitic fluid ADA activity is useful for the diagnosis of tubercular peritonitis; this method is simple and least invasive.

Adenosine Deaminase↗
PubMed1991

Study of properties of cholinephosphotransferase from fetal guinea pig lung mitochondria and microsomes.

We have reported earlier that cholinephosphotransferase (EC 2.7.8.2) is present in both mitochondria and microsomes of fetal guinea pig lung. This study was designed to compare the properties of mitochondrial and microsomal cholinephosphotransferase in fetal guinea pig lung. Various parameters, such as substrate specificity, Km values, sensitivity to N-ethylmaleimide, dithiothreitol and trypsin were measured. Both showed significant preference for unsaturated diacylglycerols over saturated diacylglycerols. Data on Km and Vmax indicate that the affinity of this enzyme for different diacylglycerols varies between the two forms. The ID50 values for N-ethylmaleimide were 20 mM and 12.5 mM for the mitochondrial and microsomal form of the enzyme, respectively. Dithiothreitol showed an inhibitory effect on both; however, the mitochondrial form was inhibited less than the microsomal form. The effects of N-ethylmaleimide and dithiothreitol on both forms of enzyme indicated that the microsomal cholinephosphotransferase requires a higher concentration of -SH for its activity than the mitochondrial enzyme does. The enzyme was inhibited by trypsin in both mitochondria and microsome under isotonic condition suggesting that this enzyme is on the outside of the membrane in both endoplasmic reticulum and mitochondria.

Animals↗
PubMed1991

Patterns of illness in parent-child pairs both hospitalized for either schizophrenia or a major mood disorder.

Results are reported of a blind rediagnosis of a consecutive series of parent-child pairs hospitalized with a diagnosis of schizophrenia or mood disorder. Patterns of illness in pairs meeting DSM-III-R criteria for either disorder were examined by contrasting the two generations on their respective distributions of diagnoses, and means of age at onset and severity of illness. While no case of mood disorder was found in the children of schizophrenic parents, 50% of the children of parents with psychotic mood disorders presented with schizophrenia. The offspring also had an earlier age at onset of illness than did their parents.

Adult↗
PubMed1991

Abnormal growth of skin fibroblasts from schizophrenic patients.

Fibroblast cultures were established from skin biopsies of 18 schizophrenic patients (14 on drug and 4 off drug) and 13 normal subjects, and growth parameters (initial growth and rate of growth) and morphology were studied. Fibroblasts from patients took significantly longer to grow than did normal fibroblasts. Cell lines were established within 2 weeks for all normal controls, but for only 6 (33%) of 18 schizophrenic patients. The rate of growth (doubling time) was also significantly longer for fibroblasts from patients than from normals. Neither time to establishment of initial growth nor doubling time was related to age, sex, age at onset, duration of illness, or medication status in the patients. Fibroblasts from normals showed uniform, long (slender), characteristic spindle-like, bipolar appearance, with unidirectional orientation, both while growing from explant as well as after subculturing. By contrast, fibroblasts from patients generally showed random size (shorter and flatter), mostly spiny, multipolar cells with short stubby projections, and an irregular orientation resulting in a criss-cross pattern, and often exhibited poor attachment. Fibroblasts from skin biopsies of patients who were drug free at the time of biopsy showed similar initial growth, doubling time, and morphology to those from patients who were receiving neuroleptic treatment. In vitro challenge of skin biopsies of normal subjects with haloperidol in culture resulted in slight delay in initial growth and marginal increase in doubling time. However, the morphology remained normal. Possible molecular mechanisms that may be associated with abnormal growth of fibroblasts in schizophrenia are discussed.

Adolescent↗
PubMed1991

Specificity of smooth pursuit eye movement and visual fixation abnormalities in schizophrenia. Comparison to mania and normal controls.

Smooth pursuit eye movements (SPEM) were assessed in 30 schizophrenic patients, 12 lithium-free manic patients, and 20 normal controls. Compared to schizophrenic patients, manic patients evidenced less SPEM impairment in an attention enhancing, sinusoidal target motion condition and had superior performance during a visual fixation condition. SPEM and visual fixation dysfunctions may be more common in schizophrenic than in acutely manic patients, even when the latter are characterized by marked attentional dysfunction, poor interepisode psychosocial functioning, and psychosis.

Adult↗