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S Chowdhury

Publications and source records attributed to S Chowdhury.

At least 109 records · Page 6Linked to original sources
PubMed1989

A knowledge-based system for data analysis and interpretation.

Traditionally, statistical packages are employed to derive or infer facts about a Universe of Discourse through data analysis and interpretation. It is analysis that serves to transform data into information. Statistical packages provide the users with relatively easy-to-use and powerful mechanics of data analysis, but up to now they do not provide much help with the design and strategies of the analysis. As such, there is a risk of misuse of these packages by statistically inexperienced users. We propose the use of knowledge-based interfaces to support this category of users in statistical evaluations. This paper discusses our experiences from the implementation of a knowledge-based system called MAXITAB. It provides guidance in the processes of data analysis and interpretation and has been programmed as an interface to the statistical package MINITAB.

Data Interpretation, Statistical↗
PubMed1988

Discontinuation of breast-feeding during episodes of diarrhoea in rural Bangladeshi children.

Discontinuation of breast-feeding during an episode of childhood diarrhoea is widely regarded as a common, high-risk practice in the developing world. We studied cessation of breast-feeding in a rural Bangladeshi population under comprehensive surveillance for medically treated diarrhoeal episodes. Among 2129 episodes in children aged under 36 months and breast-fed before the onset of diarrhoea, there were only 33 (2%) in whom breast-feeding had stopped before presentation for care. Children in whom breast-feeding had stopped (cases) differed little from those in whom it had not (controls) in respect to exclusive vs partial breast-feeding, age, gender, or several maternal characteristics (maternal age, education, and recent maternal diarrhoeal illness). In contrast, cases were more likely to have presented with clinically severe illness or to have died within 30 d of presentation (odds ratio = 2.20, P less than 0.05). We conclude that discontinuation of breast-feeding during diarrhoea is an infrequent phenomenon in this population. However, the association of cessation of breast-feeding with severe clinical outcomes may be of considerable importance, particularly in countries where discontinuation of breast-feeding is more common.

Bangladesh↗
PubMed1988

The search for an 111In labeled agent for the solid component of gastric emptying.

111In-labeled solid meal was prepared by chelation of 111In with Chelex resin bead. The effect of grinding of normal Chelex bead on 111In chelation and retention in solid meal was evaluated in an in vitro system. The Chelex resin beads were ground in a mortar-pestle to form ground Chelex resin beads. Fine particles were removed by resuspension in distilled water and centrifugation (1000 g). One hundred to 150 microCi of 111In chloride was diluted with 0.1 N HCl and mixed with 1 g of Chelex resin beads. Unbound 111In was removed by centrifugation (1000 g). The 111In-labeled Chelex resin beads were mixed with fresh egg and 111In-labeled solid meal was prepared by heating until solid. The meals were digested with HCl-pepsin (1.2 mg/mL of pepsin in 0.1 N HCl) for 4 h in a stirrer-bath (37 degrees C). Aliquots were collected at intervals for determination of 111In loss from 111In-labeled solid meal. These results suggest that 111In Chelex resin beads were retained in solid meals at a higher level than normal Chelex resin beads and other 111In-tracers.

Digestion↗
PubMed1988

Labeled polymorphonuclear leukocytes: a comparison of methodology.

Polymorphonuclear neutrophilic granulocytes were separated from anti-coagulated whole blood using three techniques. The methods employed included volex sedimentation (VS), volex sedimentation with hypotonic lysis (VSHL), and Ficoll-Hypaque gradient separation (FH). The cells were labeled with 111In-oxine and 111In-tropolone. Studies were done with both blood from normal human volunteers and with canine blood. From the cell counts and differential, the harvested granulocytes, platelets, and red blood cells per milliliter of whole blood were calculated. Using the granulocyte chemotactic response to E. coli in agarose plates, the ratio of chemotactic migration to random migration (c.m./r.m.) was determined. Survival time for 111In labeled granulocytes were also determined in a canine model. The studies demonstrated that all procedures yielded 100% viability by the Trypan blue exclusion test. Chemotactic migration and leukocyte survival times were similar amongst all techniques. With the VSHL technique, there were significantly fewer red blood cells and platelets in the final preparation approaching the results of FH separation. The results suggest that for a relatively pure granulocyte preparation VSHL is an acceptable alternative to FH.

Animals↗
PubMed1988

Measles vaccination and childhood mortality in rural Bangladesh.

To ascertain whether measles vaccination was associated with reduced mortality rates in rural Bangladeshi children, the authors conducted a case-control study in four contiguous areas, two of which had participated in an intensive measles vaccination program which began in the spring of 1982. Cases were 536 children who had died in the four-area region at the age of 10-60 months between April 1982 and December 1984. Two age- and sex-matched controls were selected from the four-area region for each case; each control had survived at least through the date of death of the matched case. Measles vaccination was associated with a 36% (95% confidence interval 21%-48%) proportionate reduction in the overall rate of death and a 57% (95% confidence interval 43%-67%) reduction in the rate of deaths directly attributed to measles or ascribed to diarrhea, respiratory illness, or malnutrition. The association of measles vaccination and reduced mortality remained unchanged after the authors restricted controls to children who had survived at least one year after the deaths of their matched cases. Moreover, children vaccinated in 1982 exhibited a sustained reduction in the rate of death in 1983 and 1984. The authors concluded that measles vaccination was associated with a pronounced and sustained reduction in the rate of death among children in this study.

Bangladesh↗
PubMed1988

Indium-111 labeled purified granulocytes in the diagnosis of synthetic vascular graft infection.

Indium-111 labeled leukocytes have been shown to be useful in the diagnosis of synthetic vascular graft infection. To minimize the potential effects of labeled red blood cells and platelets on image interpretation, the authors prepared purified autologous granulocytes (PG) from 84 ml of blood using Volex enhanced gravity sedimentation and Ficoll-Hypaque double density centrifugation. The labeling efficiency of PG with In-111 tropolone was 90 +/- 9% (mean +/- SD). Imaging was performed 18-24 hours following injection of approximately 445 microcuries of In-111 PG in 26 patients with suspected infection of vascular grafts that had been implanted 12 days to 12 years prior to the study. In ten patients with proven graft infection, seven had positive In-111 PG scans. Ten of 11 patients without infection had negative scans. In five patients with clinically equivocal findings, scan results were positive in one, negative in one, and equivocal in three. A false-positive scan occurred in a patient with an uninfected inflammatory pseudoaneurysm of an aortic graft. These results confirm an earlier report that In-111 PG imaging is a useful technique in the diagnosis of synthetic vascular graft infection.

Aged↗
PubMed1988

Single and fractionated whole body hyperthermia in murine fibrosarcoma.

The effects of single and multiple fractionated whole body hyperthermia (WBH) 41.5 degrees C on benzo(a) pyrene induced fibrosarcoma of mice were evaluated in terms of tumour response and systemic alterations of the host. While single exposure of WBH(S) 2 hrs, caused moderate inhibition of tumours and increase in the median survival time, multiple fractionated exposures [WBH(M)] caused significant enhancement of tumours with decrease in mean survival time. Tumoricidal effects associated with increased acid phosphatase and beta-glucuronidase activity were observed in both the regimes of WBH. In WBH(M) the development of thermotolerance was indicated by decreased activity of these enzymes in subsequent treatments. Elevation of plasma corticosterone and significant lymphocytopenia occurred in both the regimes. The alterations were transient in WBH(S) but persisted for more than two weeks in WBH(M), indicating that tumour enhancement is possibly influenced by corticosterone-mediated immunosuppression. In the WBH(M), the tumoricidal effects were counteracted and surpassed by the growth stimulatory physiological alterations of the host. Therefore the mode of application of WBH and the systemic responses of the host are critical factors that should be considered in designing therapeutic regimes with WBH.

Acid Phosphatase↗
PubMed1986

Radiolabeled polyvinyl alcohol particles: a potential agent to monitor embolization procedures.

Polyvinyl alcohol sponge (PVA) is a widely used angiographic embolic agent. The radiolabeling of PVA can accurately identify particle localization and may decrease the possibility of patient morbidity from embolization to distal sites. We incorporated 99mTc sulfur colloid (SC) into PVA by heating. Animal experiments demonstrated the in vivo stability of the 99mTc SC-PVA complex and the efficacy of external imaging. 99mTc SC-PVA biodistribution data and external NaI(T1) scintillation probe counts were performed, to assess anatomic localization. Embolization with this complex was performed in a patient.

Angiography↗
PubMed1985

Campylobacter infection in domestic dogs.

Campylobacter jejuni, a recently recognised human enteric pathogen, was recovered from the faeces of 21.7 per cent of domestic dogs with diarrhoea as compared with only 3.1 per cent of normal healthy dogs. The recovery rate from non-diarrhoeic, but unhealthy, domestic dogs was 6.7 per cent. The differences in the incidence of C jejuni between breeds was not statistically significant. The majority of isolations were from puppies between birth and six months old. The incidence of C jejuni in domestic dogs did not appear to be sex specific. Domestic canine infections with C jejuni could possibly be an important source of human infection, especially to those in close contact.

Animals↗
PubMed1985

Quantification of deposition of neutrophilic granulocytes on vascular grafts in dogs with 111In-labeled granulocytes.

A new radioisotopic technique has been developed for quantification of deposition of neutrophilic granulocytes on vascular grafts. Nine healthy mongrel dogs underwent bilateral femoral artery resection and reconstruction with grafts of femoral vein and Gore-Tex. Pure granulocytes that had been separated from whole blood by centrifugal elutriation were labeled with 111In-tropolone in plasma. The granulocyte harvesting efficiency was 25 +/- 12%, and the labeling efficiency was 87 +/- 7%. Three hours after injection of labeled granulocytes and 2 hours after reperfusion, the grafts were harvested and cut into several segments for study of areas of anastomoses and midsections. On the basis of the radioactivity in the blood and in anastomotic and graft sections, the area of graft sections, and the neutrophilic granulocyte and differential leukocyte counts, the number of neutrophilic granulocytes adherent to a unit area and the total number of neutrophilic granulocytes on graft sections were calculated. These quantifications of the deposition of neutrophilic granulocytes indicated that the midsections of Gore-Tex grafts retained more neutrophilic granulocytes than did the midsections of vein grafts. Although the anastomotic areas retained more neutrophilic granulocytes than did the midsections of vein grafts, the opposite finding prevailed for the Gore-Tex grafts. A major fraction of neutrophilic granulocytes on Gore-Tex grafts was incorporated into thrombus. Semiquantitative information obtained by scintigraphy of the deposition of neutrophilic granulocytes on vascular grafts also confirmed this observation.

Animals↗
PubMed1984

Improved preservation medium for Campylobacter jejuni.

An egg-based medium was found to be superior to the conventional Wang transport medium and the recently developed biphasic medium for the preservation of Campylobacter jejuni in the laboratory. Strains of C. jejuni preserved in egg-based medium maintained at 4 degrees C were viable for over 3 months. The survival of C. jejuni in egg-based medium held at room temperature (27 +/- 2 degrees C) was also relatively longer than in Wang transport medium and biphasic medium.

Animals↗
PubMed1983

Circadian rhythms in adrenal adrenaline and noradrenaline and in blood glucose levels in the bandicoot rat (Bandicota bengalensis).

The aim of the present investigation was to ascertain circadian rhythms in adrenomedullary hormones and blood glucose level in the adult male bandicoot rat. Adrenomedullary hormones and blood glucose were measured during 0600 h, 1200 h, 1800 h and 2400 h of a 24-hour period from different groups of animals. Adrenaline, noradrenaline and blood glucose levels increased during 2400 h through 0600 h and decreased during 1200 h through 1800 h. The finding indicates that there is a circadian rhythm in adrenomedullary hormones and blood glucose level in the bandicoot rat. It is suggested that circadian fluctuation in these substances may be due to diurnal variation in the activity of the animals.

Adrenal Glands↗