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Biomedical subjects

Ravi Mehrotra

Publications and source records attributed to Ravi Mehrotra.

At least 19 recordsLinked to original sources
PubMed2006

Does self-perceived mood predict more variance in cognitive performance than clinician-rated symptoms in schizophrenia?

Symptoms are known to account for a small variance in some cognitive functions in schizophrenia, but the influence of self-perceived mood remains largely unknown. The authors examined the influence of subjective mood states, psychopathology, and depressive symptoms in cognitive performance in a single investigation in schizophrenia. A group of 40 stable medicated patients with schizophrenia (20 men, 20 women) and 30 healthy comparison subjects (15 men, 15 women) were assessed on neurocognitive measures of verbal abilities, attention, executive functioning, language, memory, motor functioning, and information processing. All subjects provided self-ratings of mood prior to cognitive testing. Patients were also rated on psychopathology and depressive symptoms. Patients performed worse than comparison subjects on most cognitive domains. Within the patient group, subjective feelings of depression-dejection, fatigue-inertia, confusion, and tension-anxiety predicted (controlling for symptoms) poor performance on measures of attention, executive function, and verbal memory. In the same group of patients, clinician-rated symptoms of psychopathology and depression predicted significantly poor performance only on tests of motor function. In comparison subjects, vigor related to better, and fatigue and inertia to worse, spatial motor performance. Self-perceived negative mood state may be a better predictor of cognitive deficits than clinician-rated symptoms in chronic schizophrenia patients.

Adult↗
PubMed2006

Application of cytology and molecular biology in diagnosing premalignant or malignant oral lesions.

Early detection of a premalignant or cancerous oral lesion promises to improve the survival and the morbidity of patients suffering from these conditions. Cytological study of oral cells is a non-aggressive technique that is well accepted by the patient, and is therefore an attractive option for the early diagnosis of oral cancer, including epithelial atypia and squamous cell carcinoma. However its usage has been limited so far due to poor sensitivity and specificity in diagnosing oral malignancies. Lately it has re-emerged due to improved methods and it's application in oral precancer and cancer as a diagnostic and predictive method as well as for monitoring patients. Newer diagnostic techniques such as "brush biopsy" and molecular studies have been developed. Recent advances in cytological techniques and novel aspects of applications of scraped or exfoliative cytology for detecting these lesions and predicting their progression or recurrence are reviewed here.

Cytodiagnosis↗
PubMed2006

A behavioural and functional neuroimaging investigation into the effects of nicotine on sensorimotor gating in healthy subjects and persons with schizophrenia.

RATIONALE: Schizophrenia patients display an excessive rate of smoking compared to the general population. Nicotine increases acoustic prepulse inhibition (PPI) in animals as well as healthy humans, suggesting that smoking may provide a way of restoring deficient sensorimotor gating in schizophrenia. No previous study has examined the neural mechanisms of the effect of nicotine on PPI in humans. OBJECTIVES: To investigate whether nicotine enhances tactile PPI in healthy subjects and patients with schizophrenia employing a double-blind, placebo-controlled, cross-over design and, if so, what are the neural correlates of nicotine-induced modulation of PPI. MATERIALS AND METHODS: In experiment 1, 12 healthy smokers, 12 healthy non-smokers and nine smoking schizophrenia patients underwent testing for tactile PPI on two occasions, 14 days apart, once after receiving (subcutaneously) 12 microg/kg body weight of nicotine and once after receiving saline (placebo). In experiment 2, six healthy subjects and five schizophrenia patients of the original sample (all male smokers) underwent functional magnetic resonance imaging (fMRI) under the same drug conditions and the same tactile PPI paradigm as in experiment 1. RESULTS: Nicotine enhanced PPI in both groups. A comparison of patterns of brain activation on nicotine vs placebo conditions showed increased activation of limbic regions and striatum in both groups after nicotine administration. Subsequent correlational analyses demonstrated that the PPI-enhancing effect of nicotine was related to increased hippocampal activity in both groups. CONCLUSIONS: Nicotine enhances tactile PPI in both healthy and schizophrenia groups. Our preliminary fMRI findings reveal that this effect is modulated by increased limbic activity.

Adult↗
PubMed2006

Cognitive impairment but preservation of sexual dimorphism in cognitive abilities in chronic schizophrenia.

Neurocognitive impairment in schizophrenia is well established, though sex differences on cognitive tasks have produced equivocal findings. The present study was designed to examine performance of schizophrenia patients on a sexually dimorphic cognitive battery. The cognitive battery comprising tests of spatial (mental rotation, computerized version of the Benton Judgment of Line Orientation) and verbal abilities (phonological and semantic fluency) was administered to men (n = 22) and women (n = 21) with schizophrenia and healthy controls (n = 21 men and 21 women). A series of multivariate analyses showed that the patient group performed worse than controls on all the cognitive tasks. Cognitive sexual dimorphism on all spatial tasks favoring men and verbal tasks favoring women remained. Within the patient sample, correlational data demonstrated that earlier age at onset of illness related to poorer spatial performance. It is concluded that normal sexual dimorphism is undisturbed on both spatial and verbal tasks by the schizophrenia disease process.

Adolescent↗
PubMed2006

HIV seroprevalence in patients with tuberculosis in Allahabad, North India.

250 patients with evidence of pulmonary tuberculosis and 50 nontubercular patients as a control group were subjected to Tuberculin test, Chest X-Ray, sputum microscopy, screening for HIV by ELISA and confirmation by Western blot if ELISA test was found positive. In the study group, 11 tested positive for HIV-1 and 239 tested seronegative, however, in the control group all patients were HIV seronegative. HIV infection was most prevalent in young males in the 21-40 year age group, with a history of tuberculosis, either residing, or working in an urban area away from their family. All our cases were of the HIV-1 serotype.

Adolescent↗
PubMed2005

The relationship of structural alterations to cognitive deficits in schizophrenia: a voxel-based morphometry study.

BACKGROUND: Region of interest studies have identified a number of structure-cognition associations in schizophrenia and revealed alterations in structure-cognition relationship in this population. METHODS: We examined the relationship of structural brain alterations, identified using voxel-based morphometry, to cognitive deficits in 45 schizophrenia patients relative to 43 healthy control subjects and tested the hypothesis that structure-cognition relationship is altered in schizophrenia. RESULTS: Patients had smaller total brain, gray matter, and white matter volumes. Regional alterations were left-hemisphere specific, including: gray matter reduction of inferior frontal, lingual, and anterior superior temporal gyri; white matter reduction of posterior and occipital lobes; and gray matter increase of the putamen and the precuneus. Smaller whole brain and gray matter volumes were associated with lower premorbid intelligence quotient (IQ) and poorer performance on IQ-dependent cognitive measures in patients and to a similar extent in control subjects. Larger precuneus was associated with better immediate verbal memory in patients, whereas verbal and nonverbal memory were positively associated with inferior frontal gyrus volume in control subjects. Smaller occipital white matter volume was associated with slower information processing speed in patients but not in control subjects. CONCLUSIONS: Regional volume alterations are associated with specific cognitive deficits in schizophrenia. Some structure-cognition relationships differentiate this population from healthy control subjects.

Adolescent↗
PubMed2005

Disruption of learned irrelevance in acute schizophrenia in a novel continuous within-subject paradigm suitable for fMRI.

Learned irrelevance (LIrr) is closely related to latent inhibition (LI). In LI a to-be-conditioned stimulus (CS) is prexposed alone prior to the opportunity to learn an association between the CS and an unconditioned stimulus (UCS). In LIrr preexposure consists of intermixed presentations of both CS and UCS in a random relationship to each other. In both paradigms preexposure leads in normal subjects to reduced or retarded learning of the CS-UCS association. Acute schizophrenics fail to show LI. LI is usually demonstrated as a one-off, between-groups difference in trials to learning, so posing problems for neuroimaging. We have developed a novel, continuous, within-subject paradigm in which normal subjects show robust and repeated LIrr. We show that this paradigm is suitable for functional magnetic resonance imaging (fMRI) and gives rise, in normal subjects, to activation in the hippocampal formation, consistent with data from animal experiments on LI. We also report, consistent with previous studies of LI, loss (indeed, significant reversal) of LIrr in acute (first 2 weeks of current psychotic episode) schizophrenics. Chronic schizophrenics failed to demonstrate learning, precluding measurement in this group of LIrr. These findings establish the likely value of the new paradigm for neuroimaging studies of attentional dysfunction in acute schizophrenia.

Adult↗
PubMed2005

Sex differences and individual differences in cognitive performance and their relationship to endogenous gonadal hormones and gonadotropins.

Sexually dimorphic cognitive performance in men (n=42) and women (n=42) was related to testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin, measured in 10-ml blood samples collected between 0900 and 1030 and, among women, during the follicular phase of the menstrual cycle. Significant sex differences favored men on spatial tasks (Mental Rotation and Judgment of Line Orientation) and on an inhibition task and favored women on a verbal task (category fluency). However, there were no significant relationships between any of the hormones and cognitive performance, suggesting that there are few, if any, consistent, substantial relationships between endogenous, nonfluctuating levels of gonadal hormones or gonadotropins and these cognitive abilities in men or women.

Adult↗
PubMed2005

Histopathological changes in cases of aluminium phosphide poisoning.

Of a total of 205 poisoning deaths in our hospital in 2003, 83 cases were due to Aluminium phosphide poisoning and were further analyzed. Most vulnerable age group was 21-40 years and M:F ratio was 2:1. On naked eye examination, almost all the vital organs were found to be congested. On microscopic study, the liver showed central venous congestion, degeneration, haemorrhage, sinusoidal dilation, bile stasis, centrilobular necrosis, Kupffer cell hyperplasia, infiltration by mononuclear cells and fatty change. Microscopy of the lungs revealed alveolar thickening, oedema, dilated capillaries, collapsed alveoli and haemorrhage. In the kidney, changes were degeneration, infiltration, tubular dilation and cloudy swelling. Changes in the brain included congestion and coagulative necrosis and in the stomach, congestion and haemorrhage. Easy availability of this cheap and highly toxic substance was responsible for the sudden spurt of poisoning with aluminium phosphide.

Adolescent↗
PubMed2005

Pre and post-treatment histopathological changes in atrophic rhinitis.

Atrophic rhinitis is a chronic debilitating nasal mucosal disease of unknown etiology. It is characterized by progressive nasal mucosal atrophy, crusting, fetor and enlargement of the nasal space with paradoxical congestion. The disease induces bilateral nasal obstruction and a persistent foul odour of which the patient and by-standers are painfully aware. Primary atrophic rhinitis has decreased markedly in incidence in the last century. However the prevalence still remains high in developing countries like India. Histopathological features allow this entity to be distinguished from chronic non-specific hypertrophic rhinitis, which may have a cell-mediated immune basis underlying its pathogenesis. Histopathological examination of primary atrophic rhinitis was performed on biopsy material from 30 patients. Mucosal atrophy, squamous metaplasia, and chronic inflammatory cell infiltrate were found to characterize this disease.

Adolescent↗
PubMed2004

Patterns in melting snow and vapor deposited layers.

We have observed a natural periodic pattern occurring in partially melted snow lying on the ground under certain atmospheric conditions. We explain this phenomenon quantitatively by considering heat flow through this layer coexisting in two phases (snow and water). Our model equations exhibit a range of patterns depending on the average density of snow. Strikingly similar patterns have been observed by Plass and co-workers in monolayer depositions of Pb on heated PbCu substrates. We argue that the physics of the two phenomena, differing in length scales by 7 orders of magnitude, is similar.

Journal Article↗
PubMed2004

Neurological soft signs and their relationship to cognitive and clinical efficacy of atypical antipsychotics in schizophrenia.

Neurological soft signs (NSS) are nonspecific indicators of brain dysfunction that are found to be in excess and correlated with cognitive dysfunction and psychopathology in patients with schizophrenia. The aim of the study was to examine whether the severity of NSS determines the efficacy of atypical antipsychotics in schizophrenia. Forty-three patients with schizophrenia were assessed on psychopathology and cognitive domains of executive functioning, memory, attention, and psychomotor speed at baseline and 6 months after they had been switched from typical to atypical antipsychotics. NSS were examined at baseline. The high-NSS group showed more severe psychopathology and greater impaired cognitive function than the low-NSS group at baseline. Following treatment, there were improvements in cognitive functioning and psychopathology with the low-NSS group, which showed significant improvements on measures of verbal fluency, memory, and psychomotor speed and negative symptoms. The high-NSS group also showed improvements on most of these measures, but the improvement was less than that seen in the low-NSS group. The presence of high NSS in schizophrenia patients impedes the improvement in cognitive function with atypical antipsychotics treatment.

Adult↗
PubMed2004

Serial scrape smear cytology of radiation response in normal and malignant cells of oral cavity.

Serial scrape smears were taken from 111 patients receiving radiotherapy for squamous cell carcinoma of the oral cavity. The surface of the tumour and the normal mucosa on the opposite side was scraped before and after delivery of various fractions of radiotherapy and were evaluated by light microscopy. The number of cells exhibiting changes like multinucleation, micronucleation, nuclear budding, binucleation and cytoplasmic granulation were counted. The results were expressed as abnormality per 1000 cells. Each parameter showed a statistically significant increase with radiation dose in both normal and malignant oral cells. In the normal mucosal cells the mean values after 6Gy and 24Gy respectively were 0.83 and 2.91 (p<0.001) for cells with multinucleation, 1.83 and 4.42 (p<0.001) for micronucleation, 2.58 and 5.15 (p<0.001) for nuclear budding, 5.92 and 12.58 (p<0.001) for binucleation, and 3.67 and 7.17 (p<0.001) for cytoplasmic granulation. On the other hand, in malignant cells, the mean values before and after treatment with 24 Gy respectively, were 3.14 and 7.08 (p<0.001) for cells with multinucleation, 1.05 and 5.97 (p<0.001) for micronucleation, 2.54 and 8.82 (p<0.001) for nuclear budding 7.11 and 27.93 (p<0.001) for binucleation and 5.32 and 12.02 (p<0.001) for cytoplasmic granulation. The study showed that there is a dose-related increase in multinucleation, micronucleation, nuclear budding, binucleation and cytoplasmic granulation after various fractions of radiotherapy in both normal and malignant oral cells, however these changes are more marked in the malignant cells.

Adult↗
PubMed2004

Radiation-related cytological changes in oral malignant cells.

Carcinoma of the oral cavity constitutes approximately 40% of overall malignant tumours in India, with an incidence of about 56,000 cases per year. Radiation responses in oral cancer cells by cytology have not been extensively studied. 102 patients with squamous cell carcinoma of the oral cavity treated by fractionated radiotherapy were studied. Serial scrape smears were taken from each tumour before and after irradiation. The abnormal nuclear counts per 1000 malignant cells were 1.6 and 14.1(p<0.001) for micronucleation, 0.9 and 5.5 (p<0.001) for nuclear budding, 7.6 and 28.1(p<0.001) for binucleation and 2.4 and 11.7(p<0.001) for multinucleation respectively. The study showed a significant rise in radiation induced cytological responses. In addition, radiation changes observed included abnormal and incomplete divisions of a nucleus, fibroblast like appearance cells, and enlargement of nuclear size as well as cytoplasmic granulation. These changes may have an important role to play in understanding the mechanism of cell killing after radiotherapy.

Adult↗
PubMed2004

Fine needle aspiration diagnosis of tuberculous mastitis.

Fine needle aspiration cytology has become the first choice in diagnostic procedures in the management of a variety of breast diseases. The technique can be successfully used to diagnose granuloma in breast aspirates and to demonstrate the presence of acid-fast bacilli. Tuberculosis is rampant in developing countries and patients are prescribed antituberculous therapy on the basis of finding granuloma in breast aspirates without a culture report. In our practice, this principle has been followed with excellent results. In our experience, this technique was reliable and reproducible in diagnosing tuberculous mastitis. We report on the cytomorphological findings of this uncommon but important disorder.

Adult↗
PubMed2003

Effects of acute procyclidine administration on prepulse inhibition of the startle response in schizophrenia: a double-blind, placebo-controlled study.

Prepulse inhibition (PPI) of the startle response refers to a reduction in response to a strong stimulus (pulse) if this is preceded shortly by a weak non-startling stimulus (prepulse). Consistent with theories of deficiencies in early stages of information processing, PPI is found to be reduced in patients with schizophrenia. Atypical antipsychotics are found to be more effective than typical antipsychotics in improving PPI in this population. Anticholinergic drugs are often used to control extrapyramidal symptoms induced by antipsychotic medication, especially by typical antipsychotics, in schizophrenic patients and are known to disrupt cognitive functions in both normal and schizophrenic populations. The effect of anticholinergics on PPI in schizophrenia has not yet been examined. This study determined the effects of procyclidine, an anticholinergic drug, on PPI in patients with schizophrenia given risperidone or quetiapine and not on any anticholinergic drugs, employing a placebo-controlled, cross-over design. Under double-blind conditions, subjects were administered oral 15 mg procyclidine and placebo on separate occasions, 2 weeks apart, and tested for acoustic PPI (prepulse 8 dB and 15 dB above the background and delivered with 30-ms, 60-ms and 120-ms prepulse-to-pulse intervals). Procyclidine significantly impaired PPI compared to placebo (assessed as percentage reduction) with 60-ms prepulse-to-pulse trials and increased the latencies to response peak across all trials. The use of anticholinergics needs to be carefully controlled/examined in investigations of information processing deficits using a PPI model and reduced to the minimum level in clinical care of schizophrenia.

Acoustic Stimulation↗
PubMed2003

Asymptomatic essential thrombocythemia: a case report.

Essential thrombocythemia (ET) is a clonal disorder of unknown etiology involving multipotent hematopoietic progenitor cell and belongs to the spectrum of chronic myeloproliferative disorders (CMPD). It is rarest of the CMPD with no case reported from India. The case being presented was detected incidentally during routine investigations in an adult female who presented with mild abdominal discomfort.

Adult↗