Tc-99m Dextran lymphoscintigraphy in an infant with chylous peritoneal effusion.
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Chylous Ascites↗
Biomedical subjects
G Biswas
Publications and source records attributed to G Biswas.
Human keratinocytes express EMMPRIN, an extracellular matrix metalloproteinase inducer.
Increased levels of matrix metalloproteinases are associated with tissue degradation and remodeling during tumor invasion and wound healing. In both processes, there is evidence that cell interactions between fibroblasts and tumor cells or keratinocytes lead to increases in metalloproteinase production. We have previously isolated and purified a tumor cell surface protein, EMMPRIN (extracellular matrix metalloproteinase inducer), which stimulates production of interstitial collagenase, gelatinase A, and stromelysin-1 by fibroblasts, and we have obtained cDNA clones that encode the EMMPRIN protein from LX-1 human lung carcinoma cells. In this study we report immunolocalization of EMMPRIN around the surface of human keratinocytes in vitro and in vivo, and isolation of cDNAs that encode the entire open reading frame for EMMPRIN from a human keratinocyte library. Comparison of the EMMPRIN cDNAs from normal human keratinocytes and LX-1 human tumor cells by nucleotide sequence analysis, expression of the recombinant proteins, and in vitro translation using the cDNAs from the two sources indicate that they express very similar forms of EMMPRIN. Native EMMPRIN isolated directly from extracts of keratinocytes, however, is slightly smaller in size and is present at a lower concentration compared with that from LX-1 tumor cells. These results establish the presence of EMMPRIN in the normal epidermis and raise the possibility of its involvement in regulation of matrix remodeling at the epidermal-dermal interface.
Amino Acid Sequence↗
Comparative kinetic studies on aflatoxin B1 binding to pulmonary and hepatic DNA of rat and hamster receiving the carcinogen intratracheally.
Several epidemiological studies have discussed the outcome of inhalation of airborne aflatoxins by humans. Metabolism of aflatoxin B1 (AFB1) by lung parenchyma leading to DNA binding is reported here. The tissue distribution pattern of [3H]AFB1 radioactivity revealed the lungs to be the second most important organ after the liver to retain a considerable amount of the radioactivity (66%). The lung indicated a selective activation of AFB1 as it showed only 7.7% binding of [3H]AFB1 to pulmonary DNA. Rats and hamsters were dosed with [3H]AFB1 (2 microCi containing 40 micrograms AFB1/100 g body wt.) intratracheally (i.t.) and sacrificed at different intervals after toxin treatment. Peak binding occurred at 0.5, 1, and 2 h in case of hamster lung, rat lung, and alveolar macrophages of both the species, respectively. At the end of 24 h, the relative AFB1-DNA binding (percentage of peak binding) in hamster lung was 72% while that in rat was 24%. The relative binding in rat lung alveolar macrophages (AMs) was generally higher than that of the hamster. AFB1 binding to hepatic DNA of both the species approached the peak at 1 h after the toxin administration i.t. Under these conditions, binding of AFB1 (or its metabolites translocated to liver) to hepatic DNA of both the species progressively diminished with time in contrast to lung, as revealed by the relative binding values at 12 h for rat and hamster lung, which were 48 and 67%, respectively, while for the rat and hamster liver they were 28 and 24%, respectively. Binding of i.t. administered [3H]AFB1 to rat liver DNA is only marginally higher than that observed with hamster liver, in contrast to the wide difference observed in animals receiving AFB1 intraperitoneally. These results highlight the persistence of AFB1 binding to pulmonary DNA, and the extent of translocated AFB1 binding to hepatic DNA presents an interesting difference from that observed when the toxin was administered through a gastrointestinal route. It is worth concluding that AMs unlike many other xenobiotics, possess specific mixed function oxidase activity to epoxidize AFB1.
Aflatoxin B1↗
Chronically exposed calvarium following electrical burns.
Electrical burns of the scalp and calvarium are uncommon, but due to various conditions peculiar to India such injuries are seen frequently. The presentation of such patients at hospital is late because of the paucity of specialized care facilities and understanding of the disease process. Such injuries usually cause necrosis of the scalp and underlying calvarium with sequestered bone being retained in situ by the flimsy adhesions of underlying granulation tissue and overhanging edges of the scalp all around caused by secondary wound contraction. This paper gives our experience of 14 such cases, explaining the reasons for the chronic state and their subsequent clinical management.
Adult↗
Use of a rule based graph-theoretical system in evaluating the activity of a class of nucleoside analogues against human immunodeficiency virus.
A rule based graph-theoretical system has been used to evaluate qualitatively the activity of a class of nucleoside analogues against human immunodeficiency virus (HIV). The system identifies biologically relevant vertices (atoms) in the molecular graphs of the compounds which have the biological activity of interest. The idea is to relate biological activity with the structural or substructural characteristics of the compounds from the point of view of molecular topology (connectivity). The system brings vertices of similar or close topological environment in the respective compounds together and this is reflected in the ranges of values formed by a distance based index of the vertices, the 'distance exponent index (Dx)', where x is any real number. It is found that the system makes correct prediction of the activity of all the compounds (active as well as inactives) of both training set and the test set against HIV. It is also apparent from this study that the index D-4, which has been used here, can make a useful classification of the vertices according to their molecular environment and the system can produce significant result in a small as well as diverse data base.
Antiviral Agents↗
Development of an expert system for pediatric auditory brainstem response interpretation.
Expert systems are computer programs which incorporate artificial intelligence technology and are created to emulate the decision-making abilities of human experts. The advantage of such systems lies in their ability to capture and model expert problem solving knowledge in a domain and make it available to an unlimited number of consumers in an economic and efficient way. The purpose of this project was to develop an expert system to interpret infant auditory brainstem response data as entered by the user. The resulting system provides diagnostic conclusions regarding hearing status, type of hearing loss, and brainstem function at an accuracy level equal to that of a human expert.
Artificial Intelligence↗
Malignant orbital tumours: observation in north Bengal.
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.
Adenocarcinoma↗
Piperine, a plant alkaloid of the piper species, enhances the bioavailability of aflatoxin B1 in rat tissues.
Piperine is known to modify the biotransformation of drugs. The effect of piperine on the metabolic activation and distribution of [3H]-aflatoxin B1 (AFB1) in rats has been described. Piperine markedly inhibited liver microsome-catalysed [3H]AFB1 binding to calf thymus DNA in vitro, in a dose dependent manner. Rats pretreated with piperine accumulated considerable [3H]AFB1 radioactivity in plasma and in the tissues examined as compared to the controls. However, piperine had no influence on hepatic [3H]AFB1-DNA binding in vivo, which could possibly be due to the null effect of piperine on liver cytosolic glutathione (GSH) 5-transferase activity. Piperine-treated rat liver microsomes demonstrated a tendency to enhance [3H]AFB1 binding to calf thymus DNA in vivo. The effect of piperine on AFB1 metabolism thus closely resembles the mode of action of SKF 525-A on biotransformation of foreign compounds.
Aflatoxin B1↗
Reconstruction of a major abdominal and chest wall defect using latissimus dorsi and extended deep inferior epigastric artery flap.
Large defects of the chest and abdominal cavity are a challenging reconstructive problem. We present reconstruction of a major chest and abdominal wall defect in a patient who had recurrent chondrosarcoma. The defect extended from just below the nipple almost to the umbilicus, and measured 28 x 30 cm. An "extended" latissimus dorsi muscle flap and extended deep inferior epigastric artery flap were used for reconstruction of the defect. A 1-year follow-up of the patient is presented.
Abdominal Neoplasms↗
Operational evaluation of Guineaworm Eradication Programme--the parameters.
In order to achieve guineaworm eradication in 1990s, the Guineaworm Eradication Programme (GWEP) should operate with utmost efficiency; and needs to be concurrently evaluated for timely corrective measures. Some simple parameters, their relevance, levels and frequency at which these may be helpful to objectively evaluate the GWEP efficiency are discussed in this communication.
Algorithms↗
"Filopin" efficacy in the treatment of lymphatic filariasis.
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Acute Disease↗
Man vector contact in microfilaraemic and amicrofilaraemic human population--a case control study.
A case control study was undertaken in rural areas of Varanasi, U.P., to study the relationship of Culex quinquefasciatus landing on microfilaria--carriers and amicrofilaraemic controls. No statistically significant difference was observed in the vector landing in these two groups.
Adolescent↗
Repair of a urethral fistula following electrical burns using a gracilis muscle flap.
An unusual example of electrical burns of the genitalia resulting in a urethral fistula is reported because of its clinical rarity. Reconstruction was carried out using a unilateral gracilis muscle flap.
Adult↗
The role of hydroxyl radical in chromosomal and plasmid damage in Neisseria gonorrhoeae in vivo.
Viable Neisseria gonorrhoeae exposed to streptonigrin generate intracellular hydroxyl radical detected by spin-trapping with 5,5-dimethyl-l-pyrroline-N-oxide; gonococci exposed to paraquat generate primarily superoxide (J. Biol. Chem., 262: 13404-143048, 1987). The use of streptonigrin and paraquat provide a model with which to examine the action and site(s) of hydroxyl radical-mediated damage. N. gonorrhoeae exposed to streptonigrin, but not paraquat, developed extensive chromosomal, plasmid, and RNA damage. Addition of excess Fe+3 to the reaction mixture enhanced intracellular hydroxyl radical formation by paraquat, detectable as DNA damage. Desferal and dimethyl sulfoxide allowed approximately 25% of protection of plasmid DNA damage as judged by linear scanning densitometry. These results demonstrate DNA and RNA damage in viable organisms exposed to intracellular redox stress and confirm the critical role of hydroxyl radical in this process.
Chromosomes, Bacterial↗
Structure of a modified cytosine: an antiviral nucleoside analog, homo-Ara-C.
Homo-Ara-C [5'-(hydroxymethyl)-5'-deoxy-1-beta-D-arabinofuranosyl-3H- cytosine], C10H16N3O5, Mr = 258.25, P2,2,2, a = 8.261 (2), b = 19.644 (4), c = 6.993 (6) A, V = 1134.8 A3, Z = 4, Dx = 1.511 g cm-3, lambda (Cu Ka) = 1.5418 A, mu = 10.5 cm-1, F(000) = 548, T = 288 K, final R = 0.053 for 1189 observed reflections. Conformational features of the nucleoside include a glycosidic bond conformation in the anti range, a ribose moiety in the 2E [C(2')-endo] form like 5'-N3-Ara-C, 5-NO2-Ara-U and Ara-C and a C(5')-C(6') bond that is gauche to C(4')-O(4') but trans to C(4')-C(3').
Crystallography↗
Structure and conformation of a nucleoside analog 5-nitro-1-beta-D-arabinofuranosyluracil.
C9H11N3O8, Mr = 271, orthorhombic, P2(1)2(1)2(1), a = 9.241 (2), b = 20.518 (4), c = 6.187 (1) A, V = 1173.1 A3, Z = 4, D chi = 1.29 g cm-3, Mo K alpha, lambda = 0.7107 A, mu = 1.57 cm-1, F(000) = 600, T = 288 K, final R = 0.051 for 1078 observed reflections. Conformational features of the nucleoside include a glycosidic bond conformation in the anti range, a ribose moiety in the C(2')-endo (2E) form and the C(5')-(5') bond gauche to both C(4')-O(4') and C(4')-C(3').
Arabinofuranosyluracil↗
Characterization of translation products of the polyadenylated RNA of free and membrane-bound polyribosomes of rat forebrain.
Poly(A)+ RNA (polyadenylated RNA) isolated from membrane-bound and free polyribosomes was translated in reticulocyte lysates, and the products were analysed by two-dimensional gel electrophoresis. Several translation products were specific to membrane-bound polyribosomal mRNA, including polypeptides of 47kDa, 35kDa and 21 kDa, whereas others (e.g. of 37 kDa, 17 kDa and 14 kDa) were specific to free polyribosomal mRNA. Although many products were common to both mRNA species, cross-contamination could be ruled out on the basis of the presence of these and other specific products. The common products included a 68 kDa microtubule-associated protein, tubulin, actin, the brain form of creatine kinase, neuron-specific enolase and protein 14-3-3 and calmodulin, all of which were identified on the basis of two-dimensional gel and peptide analyses. The 35 kDa protein product of membrane-specific mRNA was co-translationally processed in vitro by microsomal membranes, resulting in its cleavage to 33 kDa (and partial glycosylation). The 33 kDa processed protein (but not the 35 kDa precursor) was integrated into both dog pancreas and rat brain microsomal membranes. The occurrence of the enzymes and calmodulin as products of membrane-bound polyribosomal mRNA is discussed in the light of their presence on rat brain synaptic plasma membranes [Lim, Hall, Leung, Mahadevan & Whatley (1983) J. Neurochem. 41, 1177-1182] and their existence in a specific component of axonal flow. It is suggested that some of these translation products of the rough endoplasmic reticulum may represent proteins destined for the plasma membrane. However, the identity and location of the 35 kDa membrane-specific product (or its processed form) still remain unestablished.
Animals↗
Some characteristics of collagen-heparin complex.
In various forms of purified collagen (powder of insoluble collagen from bovine skin, fibers from rat tail tendons, membrane from bovine gut), carboxyl groups were activated by carbodiimide to allow covalent binding of heparin. Collagen powder and collagen fibers from rat tail tendons were also incubated in a heparin solution under the same reaction conditions but without carbodiimide present to account for other forms of collagen-heparin interaction. It was found that the linkage of heparin to collagen formed in the presence of carbodiimide is stable, as heparin was minimally extractable by 0.2M buffers with a pH ranging from 5 to 9. Collagen powder incubated with heparin in the absence of carbodiimide released heparin almost completely into Tris buffer of pH 9.0. As a consequence of covalent binding of heparin to collagen, the collagen fibers became more stable as shown by their significantly reduced swelling capacity and significantly increased shrinkage temperature. Collagen fibers interacted with heparin in the absence of carbodiimide also showed some stabilization of their structure, which was, however, significantly less than with carbodiimide reaction. By two independent methods it was shown that heparin linked to collagen by a stable bond retains its anticoagulant activity. It is concluded that, in the presence of carbodiimide, heparin covalently binds to collagen thus forming an antithrombogenic surface. At the same time, collagen is crosslinked. Incubation of collagen in the solution of heparin without carbodiimide also stabilizes collagen structure, but to a significantly lesser degree. Such a linkage is unstable as heparin dissociates and is readily extractable into 0.2M Tris buffers with pH 7-9.
Animals↗