Biomedical subjects

M Das

Publications and source records attributed to M Das.

At least 19 recordsLinked to original sources

PubMed2006

Solitary pulmonary nodule: detection and management.

Pulmonary nodules are commonly detected at computed tomography (CT) of the chest. More than 95% are < or = 10 mm; of these more than 95% are benign. Visual detection of pulmonary nodules by human readers is suboptimal, particularly with small nodules < or =10 mm. Computer-assisted detection can improve sensitivity and diagnostic confidence. Due to the high proportion of malignant lesions in nodules >10 mm immediate, often invasive workup is required including contrast-enhanced dynamic CT, positron emission tomography (PET) or biopsy. However, in nodules < or =10 mm the high proportion of benign lesions requires a non-invasive work-up usually based on follow-up with unenhanced CT. Invasive procedures are only required for growing nodules. Stable nodules require further follow-up and decreasing nodules are considered benign.

Adenocarcinoma↗

PubMed2006

[Dose-reduced 16-slice multidetector-row spiral computed tomography in children with bronchoscopically suspected vascular tracheal stenosis -- initial results].

PURPOSE: To evaluate the diagnostic accuracy of contrast-enhanced dose-reduced 16-slice multidetector-row CT (MDCT) in newborns and infants with fiberoptic bronchoscopically suspected vascular-induced tracheal stenosis. MATERIALS AND METHODS: 12 children (4 days to 3 years, 1.2 - 13.5 kg body weight) were examined using i. v. contrast-enhanced 16-slice MDCT (SOMATOM Sensation 16, Forchheim, Germany) without breath-hold and under sedation (11/12). All MDCTs were performed with a dose reduction. The beam collimation was 16 x 0.75 mm, except in the case of one child. MPRs along the tracheal axis in the x-, y- and z-directions and volume-rendering-reconstructions (VRTs) were calculated based on a secondary raw data set in addition to conventional axial slices. 2 radiologists used a three-point grade scale to evaluate the image quality, motion, and contrast media artifacts as well as the usefulness of the 2D- and 3D-reconstructions for determining the diagnosis. Statistical analysis was performed on the basis of a Kappa test. RESULTS: In all cases the cause of the fiberoptic bronchoscopically suspected tracheal stenosis was revealed: compression due to the brachiocephalic trunk (n = 7), double aortic arch (n = 2), lusorian artery (n = 1), vascular compression of the left main bronchus (n = 2). In 3 patients further thoracic anomalies, such as tracheobronchial (n = 2), and vascular (n = 2) and vertebral (n = 1) anomalies were found. The attenuation in the anomalous vessels was 307 +/- 140 HU. The image noise was 9.8 +/- 1.9 HU. The mean dose reduction was 82.7 +/- 3.2 % compared to a standard adult thoracic CT. All examinations were rated as diagnostically good (median 1, range 1, k = 1). 3D images did not show any stair artifacts (median 2, range 1 - 2, k = 1). The image noise was minor to moderate and hardly any motion artifacts were seen (median 1, range 1 - 2, k = 0.8). Contrast media artifacts were rated zero to minor (median 1.5, range 1 - 2, k = 0.676). MPRs (median 1, range 1, k = 1) and VRTs (median 1, range 1, k = 1) were found to be useful for diagnosis. Subsequent vascular surgery was performed on 8 patients. CONCLUSION: Contrast-enhanced dose-reduced 16-slice MDCT is effective for demonstrating the cause of fiberoptic bronchoscopically suspected vascular-induced tracheal stenosis even in very small and severely ill children despite the small contrast media amount and free breathing.

Airway Obstruction↗

PubMed2006

OCA1 in different ethnic groups of india is primarily due to founder mutations in the tyrosinase gene.

Oculocutaneous albinism (OCA) is a heterogeneous group of autosomal recessive disorders characterized by an abnormally low amount of melanin in the eyes, skin and hair, and associated with common developmental abnormalities of the eye. Defects in the tyrosinase gene (TYR) cause a common type of OCA, known as oculocutaneous albinism type 1 (OCA1). The molecular basis of OCA has been studied extensively in different population groups, but very little information is available on Indian patients. Our investigation covering thirteen ethnic groups of India, some representing >20 million people, revealed that among 25 OCA families 12 were affected with OCA1, and that these cases were primarily due to founder mutations in TYR. We detected nine mutations and eight SNPs in TYR, of which six mutations (five point mutations & one gross deletion) were novel. In contrast to most reports describing compound heterozygotes, the presence of homozygotes in 10 out of the 12 pedigrees underscores the lack of intermixing between these ethnic groups in India. Haplotype analysis suggested a few founder chromosomes causing the disease in the majority of the patients. Direct detection of the mutations prevalent in specific ethnic groups could be used for carrier detection and genetic counselling.

Albinism, Oculocutaneous↗

PubMed2005

Calcium scoring of aortic valve calcification in aortic valve stenosis with a multislice computed tomography scanner: non-enhanced versus contrast-enhanced studies.

PURPOSE: Previous studies have shown a positive correlation between amount of aortic valve calcification (AVC) and degree of aortic valve stenosis (AVS). We have investigated whether calcium scoring of AVC from contrast-enhanced images is reliable. MATERIAL AND METHODS: Nineteen patients with suspected AVS underwent retrospectively ECG-gated multislice computed tomography (MSCT). Standardized scan protocols were applied prior to (120 KV, 133 mAseff) and after (120 KV, 500 mAseff) the administration of non-ionic contrast material. Image reconstruction was performed at 60% of the RR interval (slice thickness 3 mm, reconstruction increment 2 mm). AVC was quantified using Agatston score and calcium mass. The number of lesions was calculated. All nonenhanced images were scored using thresholds of 130 HU and 350 HU. Contrast-enhanced images were assessed with a threshold of 350 HU exclusively. RESULTS: Fifteen patients with AVCs were included in the statistical analysis. The mean Agatston score (calcium mass) in non-enhanced images was 2888.4 +/- 2844.4 (694.2 mg +/- 869.3 mg). Altering the threshold from 130 HU to 350 HU led to a 58.2% (30.5%) decrease in the AVC score (P values < 0.001). Contrast-enhanced images showed an increased Agatston score (calcium mass) of 56.2% (33.5%) compared to non-enhanced images (P values <0.05) with the same threshold of 350 HU. CONCLUSION: Quantification of AVC from contrast-enhanced images is not reliable, as contrast material simulates calcification.

Aortic Valve↗

PubMed2005

Cognitive functioning in siblings discordant for schizophrenia.

OBJECTIVE: The objective of this study was to investigate neuropsychological impairment as a genetically mediated risk indicator for schizophrenia while accounting for prevalence of schizotypy signs/symptoms in siblings. METHOD: Cognitive functioning in 25 individuals with schizophrenia, 25 unaffected siblings and 25 unrelated healthy controls, was assessed using neuropsychological tests of sustained attention, memory and learning, executive function, visual-spatial ability and psychomotor performance. RESULTS: Unaffected siblings demonstrated better performance than patients on some measures of memory and learning and executive function. Patients and siblings demonstrated impaired Full Scale IQ and verbal fluency, otherwise siblings performed similarly to healthy controls. Controlling for differences in IQ, the shared deficit in verbal fluency disappeared. CONCLUSION: Patients with schizophrenia and unaffected siblings (without schizotypy personality disorder) shared a neuropsychological deficit in verbal fluency. This deficit appeared to be mediated by IQ. Deficits, which differentiated patients from controls, may not be inherited and perhaps are related to the manifestation or treatment of schizophrenia.

Adult↗

PubMed2005

Treatment of stiff person syndrome with rituximab.

This case report is about the novel use of the anti-CD20 antibody, rituximab, in the treatment of a 41 year old woman with stiff person syndrome. She was admitted to hospital as an emergency with prolonged and painful extensor spasms affecting the neck and back, arms, and legs. The disease had progressed despite a favourable initial response to conventional treatment with intravenous immunoglobulin and cytotoxics. Treatment with rituximab induced a lasting clinical remission.

Adult↗

PubMed2004

Anti-inflammatory activity of tea (Camellia sinensis) root extract.

Pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (Camellia sinensis) root extract (TRE). TRE was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its LD50 dose of 100 mg/kg i.p. It was found that TRE inhibited the arachidonic acid-induced paw oedema in rats which indicated that TRE produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. TRE also enhanced peritoneal cell count and the number of macrophages in normal mice. It is plausible that the saponins present in TRE may be responsible for these activities of TRE.

Animals↗

PubMed2004

Inkjet printing for high-throughput cell patterning.

The adaptation of inkjet printing technology to the complex fields of tissue engineering and biomaterial development presents the potential to increase progress in these emerging technologies through the implementation of this high-throughput capability via automated processes to enable precise control and repeatability. In this paper, a method of applying high-throughput inkjet printing to control cellular attachment and proliferation by precise, automated deposition of collagen is presented. The results indicate that commercial inkjet printing technology can be used to create viable cellular patterns with a resolution of 350 microm through the deposition of biologically active proteins. This method demonstrates a combination of off-the-shelf inkjet printing and biomaterials and has potential to be adapted to tissue engineering and colony patterning applications. Adapting this method into the three-dimensional construction of cellular structures for eventual high-throughput tissue engineering using a bottom-up approach is possible.

Animals↗

PubMed2004

Phosphatidylserine efflux and intercellular fusion in a BeWo model of human villous cytotrophoblast.

Phosphatidylserine (PS) efflux characterizes cytotrophoblast apoptosis and differentiation. To evaluate whether PS externalization and intercellular fusion were secondary to apoptosis, BeWo cells were induced to differentiate by forskolin or undergo apoptosis by staurosporine. PS externalization was measured by FITC-annexin V binding, and intercellular fusion was quantified by counting nuclei in syncytial cells. During forskolin treatment, vanadate decreased PS efflux by 78.0 per cent from 68.0 [5.3] (mean [SD]) to 15.0 [8.8] Lum (x10(3)) (P<0.001), whereas Z-VAD-fmk had no effect (66.5 [7.3]). Vanadate decreased intercellular fusion from 78.1 per cent [4.1] fusion in uninhibited cultures to 23.4 per cent [2.5], compared with 10.0 per cent [1.7] in media alone. Z-VAD-fmk did not affect fusion (80.4 per cent [6.8]). Staurosporine induced PS efflux was not affected by vanadate (69.6 [5.5] Lum x10(3)), but was inhibited 87.8 per cent by Z-VAD-fmk; from 71.5 [6.2] to 8.7 [3.6] Lum (x10(3)) (P<0.001). Apoptosis was measured by the TUNEL and COMET assays, lamin B fragmentation, activation of procaspase 3, mitochondrial membrane potential, and release of mitochondrial cytochrome c and apoptosis inducing factor. There was no indication of apoptosis associated with differentiation. Thus, PS efflux and intercellular fusion occurred through a vanadate-sensitive mechanism that was independent of apoptosis.

Amino Acid Chloromethyl Ketones↗

PubMed2004

[Value of cardiac multislice spiral CT for the assessment of degenerative aortic stenosis: comparison with echocardiography].

OBJECTIVE: To non-invasively assess the severity of aortic valve stenosis (AS) by the determination of aortic valve calcification (AVC) using multislice spiral computed tomography (MSCT). MATERIALS AND METHODS: Forty-one consecutive patients (17 male, 24 female, mean age 71.0 +/- 7.9 years) with a history of AS and an aortic valve area < or = 2 cm (2) underwent retrospectively ECG-gated 4-slice MSCT and echocardiography. The AVCs were quantitatively assessed using the score described by Agatston as well as by calculating the calcium mass. The echocardiographically determined aortic valve area (AVA) and the severity of AS according to the ACC/AHA guidelines were compared to the degree of aortic valve calcifications. Pearson's correlation coefficient, cut-off values, kappa test and F-test with post hoc Bonferroni t-tests were calculated. RESULTS: Calcium scores were significantly higher in patients with severe AS, when compared to mild or moderate AS (p < 0.001). In patients suffering from severe AS, the mean Agatston score was 4125.5 +/- 1168.9 (calcium mass 904.1 +/- 263.3) while in patients with moderate and mild AS the corresponding values were 1596.3 +/- 987.0 (319.1 +/- 208.3) and 785.9 +/- 390.1 (149.1 +/- 90.2), respectively. Pearson's correlation coefficients were r = - 0.75 for the Agatston score and r = - 0.72 for the calcium mass. There was a moderate agreement between severity of AS according to the ACC/AHA guidelines and the degree of AS determined from AVC scores with kappa = 0.6091 and kappa = 0.6985, respectively. CONCLUSION: Severe AS may be differentiated from moderate or mild AS using cardiac MSCT. Extensive calcifications of the aortic valve presenting with an Agatston-Score > or = 2824 (calcium mass > or = 611) indicate a severe AS and should be taken as an indication for further diagnostic workup.

Aged↗

PubMed2004

Caloric restriction, body fat and ageing in experimental models.

Caloric restriction in animal models delays many age-related pathological conditions. Ageing rats have characteristically increased body weight, fat mass and a specific body fat distribution. This report will focus on the potential cause-effect relationship between increased fat mass and accelerated ageing. In humans, increased fat mass (obesity), and in particular increases in abdominal obesity as a result of deposition of visceral fat, are associated with the metabolic syndrome of ageing. This syndrome is associated with hyperinsulinaemia, dyslipidaemia, type 2 diabetes mellitus, atherosclerosis, hypercoagulability and hypertension. Fat tissue, however, plays a major role by secreting multiple metabolically active factors, which are potentially responsible for the development of insulin resistance. This article will review various experimental models (in animals) used to prevent insulin resistance of ageing by decreasing fat mass, and in particular, decreasing visceral fat. We suggest that this decrease in fat mass and its beneficial repercussions observed in ageing animal models may apply also to human ageing and its related pathology.

Adipose Tissue↗

PubMed2003

Glycosmis arborea extract as a hepatoprotective agent.

Glycosmis arborea is a plant possessing various medicinal properties. The aim of the present study was to investigate the hepatoprotective efficacy of the butanol extract obtained from the aerial parts of the plant. The test sample was prepared by extracting the material through different steps. The extract thus obtained was dissolved in normal saline. Albino rats were prophylactically treated with the extract (i.p.) for 3 weeks. At the end of 3rd week all the groups were injected with hepatotoxic agents. After 48 h of injection, blood was collected and livers were taken out. Different enzymes in the serum were assayed and histopathological study was performed with liver. Glycosmis arborea extract was able to overcome the toxic effects of hepatotoxic agents in terms of lowering the levels of serum GPT, alkaline phosphatase and increased level of SOD in serum. TBARS generation in liver was also altered. Moreover, necrosis of liver produced by carbon tetrachloride was reversed by the extract.

Acetaminophen↗

PubMed2003

Luteolin alleviates bronchoconstriction and airway hyperreactivity in ovalbumin sensitized mice.

OBJECTIVE AND DESIGN: Asthma is an inflammatory disease of the airways and the current focus in managing asthma is the control of inflammation. In this study, we attempted to investigate the anti-asthmatic potential of a plant derived natural compound, luteolin. MATERIAL: We used a murine model of airway hyperreactivity, which mimicked some of the characteristic features of asthma. Male BALB/c mice (8-9 weeks) were used for this study. TREATMENT: Mice (n = 6) were sensitized by intraperitoneal (i. p.) injection of 10 mg of ovalbumin (OVA) on days 0, 7 and 14 followed by aerosol inhalation (5% OVA) treatments daily beginning from day 19 to day 23. To study its preventive effect, luteolin (0.1, 1.0, and 10 mg/kg body weight; daily) was administered orally during the entire period (0 to 23 day) of sensitization. To study its curative effect, mice were first sensitized and then luteolin (1.0 mg/kg body weight daily) was given orally from day 26 to 32. The airway hyperreactivity, immunoglobulin E (IgE) in the sera, and cytokines (IFN-gamma, IL-4 and IL-5) in the bronchoalveolar lavage fluid (BALF) were measured. RESULTS: Both during sensitization and after sensitization, luteolin, at a dose of 0.1 mg/kg body weight, significantly modulated OVA-induced airway bronchoconstriction and bronchial hyperreactivity (p < 0.05). Luteolin also reduced OVA-specific IgE levels in the sera, increased interferon gamma (IFN-gamma) levels and decreased the interleukin-4 (IL-4) and interleukin-5 (IL-5) levels in the BALF. CONCLUSION: Our study showed that luteolin treatment during and after sensitization significantly attenuated the asthmatic features in experimental mice. Therefore, luteolin could be used either as a lead molecule to identify an effective antiasthma therapy or as a means to identify novel anti-asthma targets.

Airway Resistance↗

PubMed2003

Use of a reduced-intensity conditioning regimen for allogeneic transplantation in patients with chronic myeloid leukemia.

Reduced-intensity conditioning that harnesses the potential of a graft-versus-tumor (GVT) effect has been proposed as an alternative to conventional myeloablative allogeneic stem cell transplantation. The primary aim is engraftment and this can be achieved with minimal immunosuppression. In this report, we describe the use of such regimens for CML in 17 patients who received human leukocyte antigen (HLA)-matched sibling allografts. Conditioning was with fludarabine, antithymocyte globulin (ATG) and busulfan for the first 11 patients, whereas fludarabine, busulfan and TBI were used for the remaining six patients. Engraftment was prompt in most of the cases. Complications and need for supportive therapy in the immediate post-transplant period were reduced drastically. Only two patients (both in the TBI group) died within the first 100 days. Acute graft-versus-host disease (GVHD) grade II-IV was seen in seven patients. Complications occurred later on. Chronic GVHD was observed in 11/17 patients. Lung infection and GVHD were the major killers. In surviving patients, after a median follow-up of 30 months (range 37-21 months), 6/17 (35.3%) are alive. Five are disease free and one patient is still in relapse even after a second donor lymphocyte infusion. Total treatment time and cost were more than with conventional transplants. We conclude that reduced-intensity transplantation still requires further refinement.

Adolescent↗

PubMed2003

Merosin negative congenital muscular dystrophy: a short report.

We report a rare case of an infant with congenital muscular dystrophy who presented at birth with marked generalized hypotonia and normal mental development. Creatinine phosphokinase (CPK) level was markedly raised; however no white matter abnormalities were detected by brain imaging techniques. Immunohistochemical staining for merosin (laminin alpha 2) was negative, thereby confirming merosin-deficient congenital muscular dystrophy.

Female↗

PubMed2002

Enhanced frequency of micronuclei in individuals exposed to arsenic through drinking water in West Bengal, India.

In West Bengal, India arsenic in ground water has been found to be above the maximum permissible limit in seven districts covering an area of 37,493km2. In the present study, evaluation of the micronuclei (MN) formation in oral mucosa cells, urothelial cells and peripheral blood lymphocytes was carried out in the symptomatic individuals exposed to arsenic through drinking water. Forty five individuals with cutaneous signs of arsenicism from four affected districts (368.11 microg/l of As in drinking water) were considered as the exposed group and 21 healthy individuals with no symptoms of arsenic poisoning and residing in two unaffected districts (5.49 microg/l of As) were considered as controls. The exposed and control groups had similar age distribution and socioeconomic status. Standardised questionnaires were utilised and medical examination was conducted to ascertain exposure history, sociodemographic characteristics, diet, health, medication, addiction and chief symptoms in the study participants. Arsenic exposure was confirmed by measuring the arsenic content in the drinking water, nails, hair and urine samples from the volunteers. Arsenic contents in the urine, nail and hair in the exposed group were 24.45 microg/l, 12.58 and 6.97 microg/g, respectively which were significantly high in comparison to corresponding control group values of 4.88 microg/l, 0.51 and 0.34 microg/g, respectively. Exposed individuals showed a statistically significant increase in the frequency of MN in oral mucosa, urothelial cells and lymphocytes (5.15, 5.74 and 6.39/1000 cells, respectively) when compared with the controls (0.77, 0.56 and 0.53/1000 cells, respectively). Thus, the above results indicate that the symptomatic individuals exposed to arsenic through drinking water in this region have significant cytogenetic damage.

Adolescent↗

PubMed2002

Toxicity of argemone oil: effect on hsp70 expression and tissue damage in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9.

The effect of argemone oil on hsp70 expression and tissue damage was investigated by studying beta-galactosidase activity, Western blotting and hybridization, and trypan blue staining in the larval tissues of transgenic Drosophila melanogaster (hsp70-lacZ)Bg9. Different concentrations of argemone oil were mixed with food and third-instar larvae were allowed to feed on them for different time intervals (2, 4, 24, and 48 h). Argemone oil was found to induce hsp70 even in the lowest concentration of the adulterant while maximum tissue damage was observed in the higher two treatment groups. Malpighian tubules and midgut tissue reflected maximum damage as evidenced by both high beta-galactosidase activity and trypan blue staining in these tissues. A prior temperature shock treatment to the larvae was enough to protect the larvae from argemone oil-induced tissue damage as evidenced by little or no trypan blue staining. The present study suggests the cytotoxic potential of argemone oil and further strengthens the evidence for the use of hsp70 as a biomarker in risk assessment.

Animals↗

PubMed2002

Student perceptions of tutor skills in problem-based learning tutorials.

OBJECTIVE: The problem-based learning (PBL) tutor plays a role that is different from the role of a teacher in a conventional teaching format. In the Faculty of Medicine and Health Sciences, United Arab Emirates, all students are Arab nationals and tutors are expatriates with different sociocultural backgrounds from the students. This study was designed to investigate how students evaluate tutors in PBL tutorials and whether student evaluations of tutors change with the progress of students in PBL tutorials. METHODS: Differences in tutor performance evaluation by male and female students were also analysed. The students evaluated 12 tutor skills in a scale of 1-3, 1 being 'below average' and 3, 'outstanding'. Student responses from a total of 314 (98.1%) completed forms collected over 2 academic years were analysed statistically. A total of 14 tutors participated in the PBL programme. RESULTS: The analysis revealed that tutors as a group were rated as having average to outstanding tutor skills in 10 items of the evaluation form. Students and faculty perceptions were different for the tutor skills of guiding students for information management. The students expected more support from tutors, whereas the tutors tried to emphasize self-learning in the PBL curriculum. Lower scores to the tutors in the 'problem' bringing sociocultural and religious issues for discussion showed that a gap in sociocultural/religious understanding between students and tutors might influence tutor skills. CONCLUSIONS: Differences in tutor evaluation by male and female students indicate necessity of adopting different strategies by tutors in a different sociocultural background. The results of the study have direct implications for faculty development.

Attitude↗