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K Das

Publications and source records attributed to K Das.

At least 145 records · Page 8Linked to original sources
PubMed1995

Place of transvaginal sonography in the evaluation of reproductive endocrinology.

A high frequency vaginal probe with improved resolution offers a remarkable sharp clear image of pelvic organs. This is possible because of its closed proximity with target organ and non-intervention by gut or omentum. Study of ovarian follicular dynamics (folliculometry), identification of proliferative, secretory and decidual changes of endometrium (endometrial dating) in different phases of menstrual cycle and imaging of mucus secretion in the cervical canal (cervical mucus study) in the pre-ovulatory phase is possible by transvaginal probe. It is non-invasive, acceptable to patients, and thus can be repeated any number of times. A close serial monitoring offers immense wealth of information about the anatomical as well as reproductive endocrinal status of the patient. Ovulation can be predicted in advance. The case of dysovulation can be identified in first cycle of study; corrective therapy can be started in another two or three cycles, aiming at achieving perfect folliculogenesis. Once well tuned synchronised cycle is restored, the pregnancy outcome is remarkable. Thus transvaginal sonography offers one of the best reproductive endocrinology evaluation in the hand of a modern gynaecological sonologist and infertility specialist.

Female↗
PubMed1995

Role of transvaginal sonography in pelvic scan for female reproductive system.

Three hundred twenty-nine cases of early pregnancy and 116 pelvic pathology studied by transabdominal sonography were compared with 81 cases of early pregnancy and 88 cases of pelvic pathology subjected to transvaginal sonography. A high frequency vaginal probe, because of its close proximity with the target organ, produces remarkably sharp image. An accurate diagnosis is possible in great majority of cases within a short time. Vaginal sonography is done with an empty bladder. A close serial monitoring of ovarian follicles, endometrium and cervical mucus with transvaginal sonography offers an immense wealth of information about the structural and reproductive endocrinal status of the patient. Ovulation can be predicted in advance. Imaging of female reproductive system by transvaginal sonography is indispensable for any modern gynaecological care and for infertility assessment in particular.

Female↗
PubMed1994

Purification and characterization of bacterially expressed mammalian translation initiation factor 5 (eIF-5): demonstration that eIF-5 forms a specific complex with eIF-2.

Eukaryotic translation initiation factor 5, eIF-5, has been purified to apparent electrophoretic homogeneity from overproducing Escherichia coli cells expressing the cDNA of the initiation factor under the control of the T7 promoter-T7 RNA polymerase system. Purified recombinant eIF-5 mimics natural eIF-5 isolated from mammalian cells in size, in specific activity, in its ability to catalyze the hydrolysis of GTP bound to the 40S initiation complex, and in the subsequent joining with 60S ribosomal subunits to form the 80S initiation complex. Further characterization of eIF-5 demonstrates that eIF-5 specifically associates with eIF-2, forming an eIF-2.eIF-5 complex. The protein complex sediments in glycerol gradients with an apparent M(r) of 160,000, suggesting that the two proteins associate in a 1:1 stoichiometry. The association between the two initiation factors is highly specific. Addition of 32P-labeled eIF-5 to a partially purified rabbit reticulocyte initiation factor preparation that contained, in addition to eIF-2 and eIF-5, other initiation factors and many other proteins resulted in the specific binding of labeled eIF-5 only to eIF-2, forming a 160-kDa protein complex. In agreement with these observations, we found that in crude initiation factor preparations derived from rabbit reticulocyte lysates, eIF-5 was present as an eIF-2.eIF-5 complex. The significance of eIF-2.eIF-5 complex formation in the overall mechanism of GTP hydrolysis in protein synthesis initiation is discussed.

Animals↗
PubMed1994

Crystal structure of peanut lectin, a protein with an unusual quaternary structure.

The x-ray crystal structure of the tetrameric T-antigen-binding lectin from peanut, M(r) 110,000, has been determined by using the multiple isomorphous replacement method and refined to an R value of 0.218 for 22,155 reflections within the 10- to 2.95-A resolution range. Each subunit has essentially the same characteristic tertiary fold that is found in other legume lectins. The structure, however, exhibits an unusual quaternary arrangement of subunits. Unlike other well-characterized tetrameric proteins with identical subunits, peanut lectin has neither 222 (D2) nor fourfold (C4) symmetry. A noncrystallographic twofold axis relates two halves of the molecule. The two monomers in each half are related by a local twofold axis. The mutual disposition of the axes is such that they do not lead to a closed point group. Furthermore, the structure of peanut lectin demonstrates that differences in subunit arrangement in legume lectins could be due to factors intrinsic to the protein molecule and, contrary to earlier suggestions, are not necessarily caused by interactions involving covalently linked sugar. The structure provides a useful framework for exploring the structural basis and the functional implications of the variability in the subunit arrangement in legume lectins despite all of them having nearly the same subunit structure, and also for investigating the general problem of "open" quaternary assembly in oligomeric proteins.

Arachis↗
PubMed1994

A possible vulnerability locus for bipolar affective disorder on chromosome 21q22.3.

In a preliminary genome scan of 47 bipolar disorder families, we detected in one family a lod score of 3.41 at the PFKL locus on chromosome 21q22.3. The lod score is robust to marker allele frequencies, phenocopy rates and age-dependent penetrance, and remains strongly positive with changes in affection status. Fourteen other markers in 21q22.3 were tested on this family, with largely positive lod scores. Five of the other 46 families also show positive, but modest lod scores with PFKL. When all 47 families are analysed together, there is little support for linkage to PFKL under homogeneity or heterogeneity using lod score analysis, but the model-free affected-pedigree-member method yields statistically significant results (p < 0.0003). Our results are consistent with the presence of a gene in 21q22.3 predisposing at least one family to bipolar disorder.

Adolescent↗
PubMed1994

Lipid matrix-based subunit vaccines: a structure-function approach to oral and parenteral immunization.

Immunization is today the most effective defense mechanism against microbial infections. Although highly effective vaccines are currently available for a number of infectious diseases, vaccine formulations can still be improved in a number of important areas. The ability to induce antigen-specific humoral and cell-mediated immunity is crucial to the development of effective prophylactic and therapeutic vaccines for HIV and other pathogens. The approach of our laboratory has been to design and test simple, highly defined antigen-lipid complexes that would stimulate antibody and cell-mediated immune responses in the absence of any nonspecific immunological activators such as Freund's adjuvant, lipopolysaccharide (LPS), or alum. These studies have provided insight into the relationships between the properties of an immunogen and the induction of the desired immune responses. We have previously utilized this approach to define the minimal structures required for the induction of antibody responses. Our more recent studies have focused on defining the parameters involved in the induction of cell-mediated and mucosal immune responses. Toward this end we have developed a new type of subunit vaccine that is effective when given orally or intramuscularly, and elucidated structure-function relationships in peptide vaccines that affect induction of CD8+ cell responses.

AIDS Vaccines↗
PubMed1994

Incidence of neural tube defects of Lucknow over a 10 year period from 1982-1991.

Open neural tube defects (NTD) in babies, occurring over a 10 yr period (1982-91), in four major maternity hospitals of Lucknow, were identified to analyse the incidence of this disorder. The overall incidence of NTD was found to be 3.9/1000. It was significantly higher in the teaching hospital compared to non-teaching hospitals. But there was no significant difference in the incidence of NTD between the Government and Private hospitals. During the decade (1982-91) under study there was no decline in NTD births. These data could serve as base-line for the incidence of NTD in north India, as NTD is expected to decline with the introduction of folic acid for the prevention of NTD.

Humans↗
PubMed1993

Acute liver disease associated with erythromycins, sulfonamides, and tetracyclines.

OBJECTIVE: To determine whether erythromycins, sulfonamides, and tetracyclines are associated with an increased risk for acute hepatitis. DESIGN: Case-control study. SETTING: Medicaid billing data from Michigan and Florida between 1980 and 1987. PATIENTS: The 107 cases included patients hospitalized with acute symptomatic hepatitis without an identifiable cause of liver disease noted in the medical record. Four controls per case were randomly selected and were matched for age, sex, and state. RESULTS: Five cases (4.7%) and four controls (0.9%) were exposed to erythromycins, yielding an odds ratio of 5.2 (95% Cl, 1.1 to 26.6). No case or control was exposed to erythromycin estolate. Eight cases (7.5%) and three controls (0.7%) were exposed to oral sulfonamides, yielding an odds ratio of 11.4 (Cl, 2.7 to 67.8). All (except one control) had received trimethoprimsulfamethoxazole. Five cases (4.7%) and four controls (0.9%) were exposed to tetracyclines, yielding an odds ratio of 5.2 (Cl, 1.4 to 19.7). The results did not change substantively for erythromycin or sulfonamides after adjustment using multiple logistic regression for age, sex, state, and use of other hepatotoxic drugs. With tetracyclines, however, the odds ratio decreased to 3.6 (Cl, 0.9 to 14.3). Associations were also seen with isoniazid (P = 0.008) and rifampicin (P = 0.04). The number of patients developing acute symptomatic liver disease resulting in hospitalization for each million patients treated with a 10-day course of erythromycin was 2.28 cases; for sulfonamides, this figure was 4.8 cases; and for tetracycline, the figure was 1.56 cases. CONCLUSION: Erythromycin, sulfonamides, and tetracyclines are associated with acute symptomatic hepatitis resulting in hospitalization. Given the widespread use of these drugs, they will be among the more common drugs associated with hepatitis.

Acute Disease↗
PubMed1993

Safety of nonsteroidal anti-inflammatory drugs with respect to acute liver disease.

OBJECTIVE: To examine the magnitude of the risk of acute hepatitis associated with the use of nonsteroidal antiinflammatory drugs. METHODS: We calculated the annual incidence rate of hepatitis resulting in hospitalization and then performed a case-control study using 1980 to 1987 Medicaid billing data from Michigan and Florida. The 107 cases included patients with symptomatic acute hepatitis without an identifiable cause of liver disease. Four controls per case were randomly selected and were matched for age, sex, and state. Antecedent drug exposure was assessed 30 days prior to the onset of the disease in the cases and during the same period in the controls. RESULTS: The annual incidence rate (95% confidence interval) of acute idiopathic symptomatic hepatitis resulting in hospitalization was 2.2 (2.0 to 2.4) per 100,000 persons per year. Nine cases (8.4%) and 26 controls (6.1%) were exposed to nonsteroidal anti-inflammatory drugs, yielding an odds ratio of 1.4 (0.6 to 3.1). After adjustment for potential confounding variables, the odds ratio was 1.2 (0.5 to 2.8). CONCLUSIONS: Acute symptomatic idiopathic liver disease severe enough to result in hospitalization is uncommon, and no association was evident between nonsteroidal anti-inflammatory drugs and acute hepatitis. This study was large enough to exclude a relative risk of 2.8. These data suggest that acute symptomatic liver disease from nonsteroidal anti-inflammatory drugs is not a frequent clinical problem.

Abdominal Pain↗
PubMed1993

Molecular cloning and expression of cDNA for mammalian translation initiation factor 5.

Eukaryotic translation initiation factor 5 (eIF-5) catalyzes the hydrolysis of GTP bound to the 40S ribosomal initiation complex (40S.AUG.Met-tRNAf-eIF-2.GTP) with the subsequent joining of a 60S ribosomal subunit resulting in the formation of a functional 80S initiation complex. A rat cDNA that encodes eIF-5 has been isolated and expressed in Escherichia coli to yield a catalytically active eIF-5 protein. The 3.55-kb cDNA encodes a protein of 429 amino acids (calculated M(r) 48,926) with properties that are similar to eIF-5 isolated from rabbit reticulocyte lysates. The deduced amino acid sequence of eIF-5 contains sequence motifs characteristic of proteins of the GTPase superfamily.

Amino Acid Sequence↗
PubMed1993

Study of enzyme polymorphism and haemoglobin patterns amongst sixteen tribal populations of central India (Orissa, Madhya Pradesh, and Maharashtra).

A survey was conducted to study the genetic differentiation among 16 tribal groups of Orissa, Madhya Pradesh, and Maharashtra belonging to different ethnic and linguistic affiliations. Sixteen hundred and fifteen blood samples from both sexes were tested for 5 red cell enzyme systems: ACP, ESD, PGD, GLO, LDH, and Hb pattern. Three hundred and nineteen male individuals were tested for G-6-PD enzyme deficiency. The distribution of the enzyme markers and Hb show a range of variation which are more or less within the Indian range. Cases of homozygous HbSS were detected in all the tribes except 3 tribes in Orissa. Two cases of LDH Cal-1 homozygote were found in two Dravidian language speaking Orissa tribes. The chi 2-values for testing the homogeneity of gene frequencies indicate a non-significant heterogeneity for all alleles in the individual system. Within population diversity seems to be larger than between population diversity. The degree of over all genetic differentiation as measured by GST value is 0.0154 +/- 0.0071.

Alleles↗
PubMed1993

Diminished support for linkage between manic depressive illness and X-chromosome markers in three Israeli pedigrees.

The hypothesis that chromosomal region Xq27-28 harbours a gene for manic-depression has been a focus of interest in human genetics. X-linked inheritance of manic depressive illness has been re-examined in 3 multigeneration Israeli kindreds. Extension and re-evaluation of pedigree data, including new individuals, diagnostic follow-up, and analysis with DNA markers, shows greatly diminished support for linkage to Xq28. The peak lod scores in two of the pedigrees have dropped several lod units to clearly negative values at the RCP-F8-G6PD gene cluster. On the other hand, positive lod scores (Zmax = 2.09) are sustained in another pedigree at the same map location. None of the pedigrees show linkage to more proximal markers, including the Xq27 locus DXS98. Our analysis underscores the uncertainties in studying complex disorders.

Adult↗
PubMed1993

HP, GC and PI polymorphisms in sixteen central Indian tribal populations.

HP, GC and PI polymorphisms have been typed on 16 Central Indian tribal populations with a total of 1658 individuals. The distribution of allele frequencies shows a statistically highly significant heterogeneity, which may be caused by several microevolutionary factors, such as genetic drift, social and geographic isolation. Some new variants were observed in both the GC system (GC 2Cmah) and in the PI system (PI Yori). The PI variants are more frequent and are found in most of the 16 populations under study whereas the GC variants are rather infrequent and restricted to only three populations.

Alleles↗
PubMed1992

Dose dependence of acetylcholinesterase activity in neuroblastoma cells exposed to modulated radio-frequency electromagnetic radiation.

Radio-frequency electromagnetic radiation (RFR) at 915 and 147 MHz, when sinusoidally amplitude modulated (AM) at 16 Hz, has been shown to enhance release of calcium ions from neuroblastoma cells in culture. The dose-response relation is unusual, consisting of two power-density "windows" in which enhanced efflux occurs, separated by power-density regions in which no effect is observed. To explore the physiological importance of these findings, we have examined the impact of RFR exposure on a membrane-bound enzyme, acetylcholinesterase (AChE), which is intimately involved with the acetylcholine (ACh) neurotransmitter system. Neuroblastoma cells (NG108), exposed for 30 min to 147-MHz radiation, AM at 16 Hz, demonstrated enhanced AChE activity, as assayed by a procedure using 14C-labeled ACh. Enhanced activity was observed within a time window between 7.0 and 7.5 h after the cells were plated and only when the exposure occurred at power densities identified in a previous report as being effective for altering the release of calcium ions. Thus RFR affects both calcium-ion release and AChE activity in nervous system-derived cells in culture in a common dose-dependent manner.

Acetylcholinesterase↗
PubMed1992

Double pigtail cystogastric stent in the management of pancreatic pseudocyst.

We describe placement of a double pigtail cystogastric stent in 5 patients with pancreatic pseudocyst using real-time ultrasonography and fluoroscopy as guidance techniques. This was done as a two-step procedure. First, a transgastric drainage catheter was placed for a period of six days. All the patients continued to have high drainage output and the cyst size decreased, as seen sonographically. Simultaneous barium meal and sinogram were then done to measure the distance between the posterior gastric wall and the cyst. A polyurethane double pigtail stent of appropriate size was then introduced to achieve cystogastric drainage. The cyst resolved in all the patients by four weeks to six weeks, when the stent was removed endoscopically. There was no recurrence of pseudocyst during follow-up for 6 months to 13 months. None of the patients suffered any complication. Cystogastric drainage using a double pigtail stent is an easy and safe alternative to surgical cystogastrostomy.

Adult↗