Biomedical subjects
Publications and source records attributed to A K Das.
Retroperitoneal fibrosis (RPF) is an uncommon entity that usually presents as a fibrous plaque-like lesion that encases the aorta and inferior vena cava below the level of the renal arteries. We present an unusual mass-like appearance of this disease simulating a tumour, with foci of calcification, seen in a young girl.
In severe form of tetanus, even with maximum dose of muscle relaxants, spasms and apnoeic spells may persist and that may be life-threatening. The aim of this study was to assess the effect of neuroparalysing the patients and then providing ventilatory support in bringing about their recovery. Forty-nine adult patients of severe tetanus (Ablett's grade IIIA--6 patients and Ablett's grade IIIB--43 patients) were studied during the period from April, 1993 to February, 1996. Mean period of onset ie, period from trismus to first spasm, in these patients was 24 hours. Patients were neuroparalysed with a bolus dose of 2-4 mg of pancuronium followed by a continuous infusion of 1-2 mg/hour and simultaneously supported with mechanical ventilation until spasms subsided. Fourteen patients (28.6%) survived and rest died. Mean duration of ventilatory support on survived patients was 14.4 days. The commonest complication encountered during ventilatory support was respiratory tract infection observed in 36 patients (73.5%). Commonest cause of death was autonomic imbalance encountered in 15 patients (30.6%). Treatment of choice in severe tetanus should be neuroparalytic ventilatory support. With use of new generation ventilators and better intensive care facility, death in severe tetanus is likely to be very less.
The Diabetes In Pregnancy Study group India (DIPSI) is reporting practice guidelines for GDM in the Indian environment. Due to high prevalence, screening is essential for all Indian pregnant women. DIPSI recommends that as a pregnant woman walks into the antenatal clinic in the fasting state, she has to be given a 75g oral glucose load and at 2 hrs a venous blood sample is collected for estimating plasma glucose. This one step procedure of challenging women with 75 gm glucose and diagnosing GDM is simple, economical and feasible. Screening is recommended between 24 and 28 weeks of gestation and the diagnostic criteria of ADA are applicable. A team approach is ideal for managing women with GDM. The team would usually comprise an obstetrician, diabetes physician, a diabetes educator, dietitian, midwife and pediatrician. Intensive monitoring, diet and insulin is the corner stone of GDM management. Oral agents or analogues though used are still controversial. Until there is evidence to absolutely prove that ignoring maternal hyperglycemia when the fetal growth patterns appear normal on the ultrasonogram, it is prudent to achieve and maintain normoglycemia in every pregnancy complicated by gestational diabetes. The maternal health and fetal outcome depends upon the care by the committed team of diabetologists, obstetricians and neonatologists. A short term intensive care gives a long term pay off in the primary prevention of obesity, IGT and diabetes in the offspring, as the preventive medicine starts before birth.
Chikungunya fever is a viral disease transmitted to humans by the bite of infected Aedes aegypti mosquito. Like malaria and dengue, this infection has almost become endemic in India, especially central and south India. Symptoms of sudden onset of fever, chills, headache, nausea, vomiting, joint pain with or without swelling, low back pain, and rash are very similar to those of dengue but, unlike dengue, there is no hemorrhagic or shock syndrome form. Chikungunya is a self-limiting illness with no specific treatment. Travellers visiting endemic areas should be careful and take precautions to see that they are not bitten by mosquitoes.
OBJECTIVE: The striking homology of the Mycobacterium tuberculosis mammalian cell entry operons (mce1, mce2, mce3 and mce4) with other mycobacterial species and the proposed role of the mammalian cell entry protein 1A (Mce1A) of M. tuberculosis to facilitate invasion of host cells have led us to look into the finer details of these proteins in order to better understand their structure-function relationship. DESIGN: We performed sequential alignments and secondary structure predictions of Mce1A, Mce2A, Mce3A and Mce4A, and compared these results with results from homology modeling by fold prediction and threading. RESULTS: Sequential alignments showed that Mce1A and Mce2A are highly homologous, close to 70%, while the other combinations gave only about 30% similarities. The major parts of the proteins aligned without gaps and there were striking similarities by secondary structure predictions indicating that the proteins would have similar folds and to be alpha/beta proteins like the previously reported Mce1A model based on Colicin N. Fold prediction showed that the best templates for Mce2A were substrate-binding domain of DnaK and slow processing precursor penicillin acylase from Escherichia coli while the alpha-domains of Mce3A and Mce4A could both be modeled using the cytoplasmic domain of serine chemotaxis receptor as template. CONCLUSION: Although different templates had to be used to model the MceA proteins, functional information may be derived that is relevant for their overall function in M. tuberculosis. The beta-domain is probably involved in binding with the receptors on target cells while the alpha-domain is more likely to be involved in pore formation. As predicted from the folds, Mce3A and Mce4A model structures indicate a lipid bound conformation and therefore may be required in signaling events of the mammalian cell entry process.
The Volmer-Weber mode for growing polycrystalline films, which comprises island, network, and channel stages before the films become continuous, is well known for its complex stress behavior with compressive and tensile stress alternating in the initial three growth stages. Recently, two new mechanisms for the compressive stress have been proposed [Phys. Rev. Lett. 88, 156103 (2002); 89, 126103 (2002)], which account for the reversibility of stress generation and relaxation. We show that the two mechanisms play only minor roles for the development of compressive stress, which is confirmed to be due to capillarity effects in the precoalescence stage.
The methanolic extract of Leonurus sibiricus aerial parts injected intraperitoneally at dose of 250 and 500 mg/kg showed a significant analgesic effect in acetic acid-induced writhing in mice. Moreover, when given orally to rats at dose of 200 and 400 mg/kg, it showed a significant anti-inflammatory activity against carrageenin induced rat paw edema in rats.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Fluctuations in arc plasma devices are extremely important for any technological application in thermal plasma. The origin of such fluctuations remains unexplained. This paper presents a theory for observed fluctuations in atmospheric pressure arc plasma devices. A qualitative explanation for observed behavior on atmospheric pressure arc plasma fluctuations, reported in the literature, can be obtained from the theory. The potential of the theory is demonstrated through comparison of theoretical predictions with reported experimental observations.
(1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production.
The TB1-5 76C monoclonal antibody raised against a synthetic 60-mer peptide in the N-terminal part of the Mce1A mammalian cell entry protein of Mycobacterium tuberculosis has previously been shown to react with a linear epitope in the KRRITPKD region, residues 131-138 in Mce1A, and to cross-react with Mce1F. Six additional monoclonal antibodies raised against the same peptide were also shown to cross-react with Mce1F. Four of them reacted with a linear epitope in the same area, indicating that this area is immunodominant but showed distinct differrences in fine specificity. Two monoclonal antibodies did not react with synthetic peptides from this region on the solid phase in enzyme-linked immunosorbent assay, indicating greater influence of conformation on reactivity. None of the monoclonal antibodies reacted with 14-mer synthetic peptides from the corresponding area in Mce2A, Mce3A, Mce4A, M. avium, M. smegmatis or M. leprae. The reaction pattern of the monoclonal antibodies was analysed in relation to our model of the Mce1A molecule (AK Das et al. Biochem Biophys Res Commun 2003;302:442-7). The epitope is located on the surface of Mce1A, at the distal beta-strand-loop region in the beta-domain supporting its potential role in promoting uptake of M. tuberculosis in host cells. Monoclonal antibody TB1-5 19C cross-reacted with glutathione S-transferase of Schistosoma japonicum containing a PKE triplet. Monoclonal antibody TB1-5 76C gave a major band at about 44 kDa in Western blotting of M. tuberculosis sonicate, whereas polyclonal rabbit anti-Mce1A peptide antibodies reacting with the extended TTPKNPTKRRITPKDVI area of Mce1A showed a distinct band above the 160 kDa molecular mass standard.
The methanolic extract of leaves of Lippia nodiflora Linn. was tested for its anti-inflammatory and antinociceptive activities. The extract showed a significant (P < 0.001) anti-inflammatory activity comparable to phenylbutazone against carrageenin-induced paw edema in rats and a significant (P < 0.001) antinociceptive activity comparable to diclofenac sodium in acetic acid induced writhing in white albino mice.
Taking advantage of the spin information in present day computing is expected to yield an enormous increase in efficiency. A promising ferromagnetic material compatible with semiconductors for room temperature applications is MnAs. By sensitive cantilever beam magnetometry, we discovered that alpha-MnAs films on GaAs(001) exhibit an additional small out-of-plane component of the magnetization which is magnetically coupled with the dominant in-plane magnetization. We demonstrate that by regarding the two components as independent inputs, the alpha-MnAs layer can be utilized as a logic gate with nonvolatile output. The logic functionality of the layer can be preselected to be AND or OR at run time, thus offering the perspective for programmable magnetologic devices.
Thin epitaxial films of MnAs--promising candidates for the spin injection into semiconductors--are well known to undergo simultaneously a first-order structural and magnetic phase transition at 10-40 degrees C. The evolution of stress and magnetization of MnAs/GaAs(001), both measured quantitatively with our cantilever beam magnetometer at the coexistence region of alpha-MnAs and beta-MnAs, reveal an orthorhombically distorted unit cell of the ferromagnetic phase, which provides important clues on the origin of ferromagnetism in MnAs.
A 38-year-old woman with a duplicated right collecting system and a history of right upper-pole heminephrectomy was referred for persistent dysuria and right lower-quadrant abdominal discomfort. Imaging identified a remnant ureter and a ureterocele filled with what appeared to be a large homogenous stone. At cystoscopy, the ureterocele was incised with a holmium:YAG laser, releasing a large quantity of white milky fluid (milk of calcium). There was no evidence of any solid material. Endoscopic evaluation should be the first step in patients with stones in a ureteral stump because milk of calcium may be the etiology of what appears to be a large stone burden in an obstructed system.
Explore the source record for details and available documents.
BACKGROUND: Thrombolysis is an expensive medical intervention for ischemic stroke and hence there is a need to study the feasibility of thrombolysis in rural India. AIMS: To asses the feasibility and limitations of providing thrombolytic therapy to acute ischemic stroke patients in a rural Indian set-up. MATERIAL AND METHODS: The first 64 consecutive patients registered under the Acute Stroke Registry in a university referral hospital with a rural catchment area were studied as per a detailed protocol and questionnaire. RESULTS: Of the 64 patients 44 were ischemic strokes, and 20 were hemorrhagic. Thirteen (29.55%) patients with ischemic stroke reached a center with CT scan facility within 3 hours, of whom only 7 (15.91%) were eligible to receive thrombolytic therapy as per the existing clinical and radiological criteria, but none received the therapy. Of the remaining 31 (70.45%) who arrived late, 11 (25%) had no clinical and radiological contraindications for thrombolysis, except the time factor. All the patients belonged to a low socioeconomic status and a rural background. CONCLUSION: Though a large proportion of ischemic stroke patients were eligible to receive thrombolytic therapy, the majority could not reach a center with adequate facilities within the recommended time window. More alarmingly, even for those patients who reached within the time window, no significant attempt was made to initiate thrombolysis. These data call not only for attention to improve existing patient transport facilities, but also for improving the awareness of efficacy and therapeutic window of thrombolysis in stroke, among the public as well as primary care doctors.