Biomedical subjects
Publications and source records attributed to S Das.
To define the effect of vecuronium on neonate, 25 elective caesarean sections were performed under general anaesthesia using vecuronium bromide as a muscle relaxant. No clinically appreciable depression was found in neonates following the use of this muscle relaxant.
We describe a technique for renal biopsy using laparoscopic guidance. Retroperitoneal laparoscopic dissection and exposure is facilitated by a simple balloon-expanding device made of a rubber glove tied around a catheter. Laparoscopic renal biopsy is associated with less morbidity than open renal biopsy and is ideal when percutaneous renal biopsy is contraindicated or is not feasible.
The long-term efficacy of trabeculectomy in controlling intraocular pressure (IOP) has been found unsatisfactory in various complicated and refractory glaucomas. The most common cause for failure is excessive scarring at the filtering site. Several wound modulating agents which reduce scarring have been tested. In this study, 5-Fluorouracil (5-FU), a halogenated pyrimidine analogue and a potent anti-mitotic agent, was applied for seven days after trabeculectomy in eighteen complicated and unsuccessful filtering glaucomas, at a daily dosage of 5 mg in the form of 0.5 ml subconjunctival injections. The common postoperative complications encountered were corneal epithelial erosion (38%), wound leakage (16%), subconjunctival haemorrhage (32%) and hyphaema (10%), all during the first 7 to 10 days. Monitoring at regular intervals up to six months showed adequate control of IOP (less than 22mm Hg.) in 88% of the cases. Cases of aphakic glaucoma and neovascular glaucoma showed poor response. Use of 5-FU as an adjuvant to filtering surgery in various complicated glaucomas improves the long-term results.
End-stage renal disease secondary to vesicoureteral reflux often necessitates removal of the affected kidney and its refluxing ureter. Advances in laparoscopic techniques have made nephroureterectomy through the laparoscope possible in a minimally invasive way. We describe our surgical steps for laparoscopic nephroureterectomy in all 11-year-old girl with end-stage reflux nephropathy. Reduced trauma of surgical access, minimal postoperative morbidity, shorter hospital stay, and minimal scarring make laparoscopic nephroureterectomy a comparatively desirable surgical approach, especially in pediatric patients.
We describe three patients with nephrotic syndrome and non-cirrhotic portal fibrosis. In two of them, the liver disorder preceded the nephrotic syndrome while in the third patient the two conditions presented together. All three patients achieved remission of nephrotic syndrome with prednisolone and cyclophosphamide.
A comparative study has been performed on the relationship between vitamin E and immunofunction in normal and malignant condition in human and murine systems. Further, the effects of supplemental vitamin E on tumor take, host survival and tumor growth have been studied in a transplantable lymphoma in mice. Vitamin E was assayed in serum samples from normal subjects and from patients with leukemia and lymphoma by high performance liquid chromatography (HPLC). The murine group included Dalton's ascitic lymphoma (DL), Schwartz lymphoblastic leukemia (SVL) and Moloney lymphoblastic leukemia (MVL). Serum vitamin E was found to be lower than that of the normal controls in all cases of leukemia and lymphoma both in human and animal system. The levels of immunoglobulins (IgG and IgM) were found to be higher in mice with leukemia and lymphoma. Supplementary vitamin E administered at the initial phase of development of murine lymphomas reduced the rate of tumor growth, improved host survival and elevated serum vitamin E level. Vitamin E supplementation also activated specific mitogen induced blastogenesis of peripheral blood lymphocytes (PBL) and elevated serum IgG level. IgM remained unaltered and macrophage activity did not seem to be affected. The present findings indicated a low status of vitamin E in tumor bearing host and a beneficial effect of supplemental vitamin E on the host which was mediated by the host immune system.
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Sixty-one cases of malignant orbital tumours were analysed retrospectively in relation to the incidence, age, sex, race, anatomical site of origin of the tumours and their histological types in North Bengal. Retinoblastoma is the commonest type (65%) followed by adenocarcinoma (10%), squamous cell and basal cell carcinoma (8.8% each). Other tumours were rarely encountered.
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The yeast artificial chromosome (YAC-13HH4), which spans a 440-kb region of DNA just distal to the CD3 locus on chromosome 11 at band q23, has been used to characterize a range of chromosomal translocations in acute leukemias from both adults and infants. In situ hybridization was performed on metaphase cells from bone marrow of 17 leukemias and two cell lines with a variety of chromosome 11q23 abnormalities. It was established that in infant leukemias the translocations t(11;19), t(4;11), and t(5;11) had occurred in the region defined by YAC 13HH4. Additionally, the translocations t(4;11), t(6;11), t(9;11), t(X;11), and t(10;11) in other leukemias were found to disrupt the same region of chromosome 11q23, although an exception was found in one t(6;11) translocation for which the breakpoint was distal to the YAC. One patient had a t(9;11) translocation in a therapy-related leukemia, suggesting that this class of etoposide-related malignancy has similar breakpoints to those occurring in de novo leukemias. An example of a lymphoma-derived translocation t(4;11) was shown to involve a deletion of the region defined by YAC 13HH4. A leukemia with a deletion on chromosome 11 (q23-q25) was also studied and it was shown that the YAC sequence was unaffected. It was concluded that, with a few exceptions, the translocations at 11q23 in a wide range of acute infant and adult leukemias occur in a common region and may result from a common underlying mechanism.
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The Drosophila melanogaster ribosomal DNA (rDNA) functions as an X-Y meiotic pairing site. Deletions encompassing the X chromosomal rDNA block (located in the heterochromatin) disrupt X-Y pairing and disjunction. Insertions of single, complete rRNA genes at ectopic locations on the heterochromatically deficient X partially restore X-Y pairing capacity. This study was undertaken to test fragments of an rDNA repeat for the ability to stimulate X-Y pairing and disjunction and to test for relationships between pairing capacity and two other phenotypes associated with rDNA insertions: transcription and the ability to organize a nucleolus. Insertions of three different fragments, all of which retained the rDNA promoter and upstream spacer sequences and which differed among each other in the length of downstream sequences, were obtained by P-element mediated transformation. One of the fragments is truncated only 140bp downstream from the promoter. Insertions of all three fragments proved capable of stimulating X-Y disjunction. Double insertions were substantially more effective than single insertions. RNA/PCR analysis was used to show that transcripts initiated at the inserted rDNA promoters are present in testis RNA from all insertions. Treatment with an antinucleolar antibody revealed that none of the insertions was associated with a mininucleolus. Thus promoter-containing rDNA fragments are autonomously capable of being transcribed and of functioning as X-Y pairing sites, but not of forming a mini-nucleolus.
Three overlapping yeast artificial chromosomes (YACs) spanning a 780 kb region of DNA around the CD3 locus on chromosome 11 have been isolated and characterised. The individual cloned regions have been mapped by in situ hybridisation to chromosome band 11q23, and a restriction enzyme map of this region has been constructed. The positions of these clones in relation to a series of leukaemia-associated chromosomal translocations has also been determined. It was concluded that, although two clones lay entirely proximal to the breakpoints examined, the third clone (13HH4) encompassed the breakpoints for the translocations t(4;11), t(6;11), and t(9;11). The t(9;11) was observed in an acute myeloid leukaemia in a patient previously treated for an unrelated malignancy. It would thus appear that the breakpoints at chromosome band 11q23 occurring in therapy-related leukaemias are in the same region as those found in adult and childhood acute leukaemias and may result from a common underlying mechanism.
We have previously shown that the maize transposable element Ds1 introduced into maize plants by agroinfection can be excised from the genome of geminivirus maize streak virus (MSV). Excision depended strictly on the presence of an active Ac element in the plants. In this study, the excision products or "footprints" left in the MSV genome after Ds1 excision were extensively characterized and the effects of flanking sequences on Ds1 excision were analysed. Most types of footprints obtained were comparable to those described for Ds1 excision in the maize genome, and could be explained by the models proposed for excision of plant transposable elements. In two revertants, however, some terminal sequences of the Ds1 element were found to have been left behind at the excision site. The finding of this novel type of Ds1 footprint indicated that gene conversion events occurred during and/or after Ds1 excision from the MSV genome. A partial deletion of one copy of the 8 bp duplications flanking the Ds1 element had no effect on the frequency or on the types of footprints of Ds1 excision from the MSV genome. Thus, the duplicated 8 bp sequences flanking the transposable element are not involved in Ds1 excision. These results, as well as a statistical analysis of the modifications of the bases flanking the Ds1 element after excision, are discussed in terms of excision models.