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Biomedical subjects

D Choi

Publications and source records attributed to D Choi.

At least 109 records · Page 6Linked to original sources
PubMed1995

Glutamine reduces bacterial translocation after small bowel transplantation in cyclosporine-treated rats.

Bacterial translocation (BT) of enteric organisms is a major cause of sepsis in patients undergoing small bowel transplantation (SBT). Cyclosporine (CsA) may be toxic to intestinal epithelium and increase the risk of BT. Glutamine (Gln) is the preferred enterocyte fuel and maintains graft epithelial integrity in experimental SBT. This study determined the effects of CsA on mucosal structure and function of transplanted intestinal isograft and examined whether Gln-enriched diet reversed CsA-induced intestinal toxicity. Thirty-three adult Lewis rats underwent resection of the distal 60% of small bowel and received an orthotopic jejunal isograft. Rats received either elemental diet with 2% Gln or the same diet with balanced nonessential amino acids (non-Gln) by gastrostomy for 10 days. CsA (15 mg/kg, im) or olive oil was injected daily. Rats were assigned to four groups: non-Gln with vehicle, non-Gln with CsA, Gln with vehicle, and Gln with CsA. Mucosal villous height, surface area, crypt depth, 14C glucose absorption, BT to mesenteric lymph nodes (MLN), and body weight change were evaluated. The non-Gln with CsA group had the highest incidence of BT (P < 0.001). Gln groups had significantly decreased BT (P < 0.01) and increased crypt depth and villous surface area (P < 0.01) when compared to non-Gln groups. Body weight significantly decreased in CsA groups when compared to non-CsA groups (P < 0.01). These results indicate at CsA significantly decreased body weight and increased BT without decreasing mucosal structure and glucose absorption of intestinal isografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

CT of the bronchus intermedius: frequency and cause of a nodule in the posterior wall on normal scans.

OBJECTIVE: A focal nodule in the posterior wall of the bronchus intermedius is occasionally observed on normal CT scans. The purpose of this study was to determine the frequency and the anatomic cause of this finding. MATERIALS AND METHODS: We prospectively analyzed helical CT scans (10-mm collimation and 10-mm/sec table speed) for evaluating nodules in the posterior wall of the bronchus intermedius from 280 consecutive subjects. A focal round elevation in the posterior wall of the bronchus intermedius was considered a nodule. Frequency of visualization of the nodule was recorded. In patients showing such nodularity, additional enhanced CT scans with thinner slices (5-mm collimation and 5-mm/sec table speed) were obtained to elucidate the nature of the nodularity. RESULTS: Nodularity in the posterior wall of the bronchus intermedius was observed in 14/280 total subjects (5%) on 10-mm collimation CT scans. On thin-section CT scans, the nodularity was caused by a branch of the vein from the posterior segment of the right upper lobe (10/14, 71%) or by a branch of the vein from the superior segment of the right lower lobe (4/14, 29%). The vein from the upper lobe that caused nodularity in the posterior wall of the bronchus intermedius drained into either the inferior pulmonary vein (7/10) or the superior pulmonary vein (3/10). In all patients whose nodularity was caused by the vein from the superior segment of the right lower lobe, the vein drained into the inferior pulmonary vein. CONCLUSION: Focal nodularity in the posterior wall of the bronchus intermedius was caused by the draining pulmonary vein, and it was observed in 5% of normal subjects. This nodularity should be differentiated from uniform or lobular thickening associated with abnormality in the bronchus intermedius.

Adolescent↗
PubMed1994

The product of the tobacco mosaic virus resistance gene N: similarity to toll and the interleukin-1 receptor.

The products of plant disease resistance genes are postulated to recognize invading pathogens and rapidly trigger host defense responses. Here we describe isolation of the resistance gene N of tobacco that mediates resistance to the viral pathogen tobacco mosaic virus (TMV). The N gene was isolated by transposon tagging using the maize Activator transposon. A genomic DNA fragment containing the N gene conferred TMV resistance to TMV susceptible tobacco. Sequence analysis of the N gene shows that it encodes a protein of 131.4 kDa with an amino-terminal domain similar to that of the cytoplasmic domain of the Drosophila Toll protein and the interleukin-1 receptor (IL-1R) in mammals, a nucleotide-binding site (NBS), and 14 [corrected] imperfect leucine-rich repeats (LRR). The sequence similarity of N, Toll, and IL-1R suggests that N mediates rapid gene induction and TMV resistance through a Toll-IL-1-like pathway.

Amino Acid Sequence↗
PubMed1994

Lipid-derived signals that discriminate wound- and pathogen-responsive isoprenoid pathways in plants: methyl jasmonate and the fungal elicitor arachidonic acid induce different 3-hydroxy-3-methylglutaryl-coenzyme A reductase genes and antimicrobial isoprenoids in Solanum tuberosum L.

Induction of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR; EC 1.1.1.34) is essential for the synthesis of steroid derivatives and sesquiterpenoid phytoalexins in solanaceous plants following mechanical injury or pathogen infection. Gene-specific probes corresponding to different HMGR genes (hmg1 and hmg2) were used to study HMGR expression in potato tissue following treatment with methyl jasmonate, a lipoxygenase product of linolenic acid, or arachidonic acid, an elicitor present in the lipids of the potato late blight fungus Phytophthora infestans. Treatment of potato discs (2.2 cm in diameter) with low concentrations (0.45-45 nmol per disc surface) of methyl jasmonate nearly doubled the wound-induced accumulation of hmg1 transcripts and steroid-glycoalkaloid (SGA) accumulation, reduced the abundance of hmg2 transcripts, and did not induce phytoalexins. High concentrations of methyl jasmonate (2-4.5 mol per disc surface) suppressed hmg1 mRNA and SGA accumulation but did not affect hmg2 mRNA abundance or induce phytoalexins. In contrast, arachidonate treatment strongly suppressed hmg1 and strongly induced hmg2 mRNA in a concentration-dependent manner. There was a corresponding suppression of SGA accumulation and an induction of sesquiterpene phytoalexin accumulation by this elicitor. Lipoxygenase inhibitors reduced the wound-induced accumulation of hmg1 transcripts and suppressed SGA levels, effects that were overcome by exogenous methyl jasmonate (45 nmol per disc surface). The results (i) suggest that methyl jasmonate can function as a signal for hmg1 expression and SGA induction following wounding and (ii) indicate that the arachidonate- and jasmonate-response pathways are distinct in relation to HMGR gene expression and isoprenoid product accumulation. The results also are consistent with placement of the HMGR activities encoded by hmg1 and hmg2 within discrete steroid and sesquiterpenoid biosynthetic channels.

Journal Article↗
PubMed1994

Editorial

Explore the source record for details and available documents.

Journal Article↗
PubMed1994

Effect of passive and active recovery on the resynthesis of muscle glycogen.

The purpose of this investigation was to determine the effect of passive and active recovery on the resynthesis of muscle glycogen after high-intensity cycle ergometer exercise in untrained subjects. In a cross-over design, six college-aged males performed three, 1-min exercise bouts at approximately 130% VO2max with a 4-min rest period between each work bout. The exercise protocol for each trial was identical, while the recovery following exercise was either active (30 min at 40-50% VO2max, 30-min seated rest) or passive (60-min seated rest). Initial muscle glycogen values averaged 144.2 +/- 3.8 mmol.kg-1 w.w. for the active trial and 158.7 +/- 8.0 mmol.kg-1 w.w. for the passive trial. Corresponding immediate postexercise glycogen contents were 97.7 +/- 5.4 and 106.8 +/- 4.7 mmol.kg-1 w.w., respectively. These differences between treatments were not significant. However, mean muscle glycogen after 60 min of passive recovery increased 15.0 +/- 4.9 mmol.kg-1 w.w., whereas it decreased 6.3 +/- 3.7 mmol.kg-1 w.w. following the 60 min active recovery protocol (P < 0.05). Also, the decrease in blood lactate concentration during active recovery was greater than during passive recovery and significantly different at 10 and 30 min of the recovery period (P < 0.05). These data suggest that the use of passive recovery following intense exercise results in a greater amount of muscle glycogen resynthesis than active recovery over the same duration.

Adult↗
PubMed1993

Cancer clusters: the importance of monitoring multiple geographic scales.

Analysis of cancer incidence data at a variety of geographic scales provides surveillance information that can allay fears of the general public, prevent costly and unwarranted epidemiologic studies driven by political pressures, and target appropriate cases for further investigation. We systematically examined New Jersey Cancer Registry data (1979-1985) for childhood and young adult (0-24 years) cancers at multiple geographic scales--at the state level, then by degree of urbanization, county boundaries, and minor civil divisions. The state had increased rates for some cancers when compared to four other SEER (Surveillance, Epidemiology and End Results) states. No meaningful patterns at either the most urban/suburban/most rural scales or at the county level of analysis were found. At the minor civil division level, the Ederer, Myers and Mantel method found evidence of clustering of pediatric and young adult cases statewide. Stratification of cases by race yielded even stronger findings and indicated that whites had clustering of cases for several cancer types. In-depth analysis of individual cases yielded hypotheses for investigating identified clusters.

Adolescent↗
PubMed1993

The reaction with polytene chromosomes of antibodies raised against Drosophila E75A protein.

The steroid insect molting hormone ecdysone rapidly induces a small number of polytene chromosome puffs in Drosophila. The Ashburner model proposes that the corresponding early genes encode proteins involved in both the induction of the late genes and the repression of the early genes. The Drosophila E75 early gene has been isolated and two of its products, E75A and E75B, have been shown to be members of the steroid receptor superfamily. We have now prepared antisera directed against A- and B-specific regions of the E75 proteins. Antisera and a monoclonal antibody raised against E75A, the major larval protein product of the E75 gene, bind to discrete sites in native salivary gland chromosomes. These sites are closely correlated with early and late ecdysone responsive loci.

Animals↗
PubMed1993

Black leaders' perceptions of the year 2000 public health goals for black Americans.

We surveyed 1196 Black health and political leaders on their perceptions about the US Department of Health and Human Services' Healthy People 2000 public health goals. Respondents identified reducing the incidence of acquired immunodeficiency syndrome, improving maternal and infant health, and controlling sexually transmitted diseases as the three most important public health goals for Black Americans that are amenable to intervention. The leaders assigned nearly all responsibility for prevention efforts to the federal government and the individual. With the American health care system now in flux, Black leaders need to organize to see that these priority issues are addressed.

Black or African American↗
PubMed1992

Rapid stimulation of 5-lipoxygenase activity in potato by the fungal elicitor arachidonic Acid.

The activity of lipoxygenase (LOX) in aged potato tuber discs increased by almost 2-fold following treatment of the discs with the fungal elicitor arachidonic acid (AA). Enzyme activity increased above that in untreated discs within 30 min after AA treatment, peaked at 1 to 3 h, and returned to near control levels by 6 h. The majority of the activity was detected in a soluble fraction (105,000g supernatant), but a minor portion was also associated with a particulate fraction enriched in microsomal membranes (105,000g pellet); both activities were similarly induced. 5-Hydroperoxyeicosatetraenoic acid was the principal product following incubation of these extracts with AA. Antibodies to soybean LOX strongly reacted with a protein with a molecular mass of approximately 95-kD present in both soluble and particulate fractions whose abundance generally corresponded with LOX activity in extracts. LOX activity was not enhanced by treatment of the discs with nonelicitor fatty acids or by branched beta-glucans from the mycelium of Phytophthora infestans. Prior treatment of the discs with abscisic acid, salicylhydroxamic acid, or n-propyl gallate, all of which have been shown to suppress AA induction of the hypersensitive response, inhibited the AA-induced increment in LOX activity. Cycloheximide pretreatment, which abolishes AA elicitor activity for other responses such as phytoalexin induction, did not inhibit LOX activity in water- or elicitor-treated discs but enhanced activity similar to that observed by AA treatment. The elicitor-induced increase in 5-LOX activity preceded or temporally paralleled the induction of other studied responses to AA, including the accumulation of mRNAs for 3-hydroxy-3-methylglutaryl coenzyme A reductase and phenylalanine ammonia lyase reported here. The results are discussed in relation to the proposed role of the 5-LOX in signal-response coupling of arachidonate elicitation of the hypersensitive response.

Journal Article↗
PubMed1992

Differential induction and suppression of potato 3-hydroxy-3-methylglutaryl coenzyme A reductase genes in response to Phytophthora infestans and to its elicitor arachidonic acid.

Induction of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is essential for the biosynthesis of sesquiterpenoid phytoalexins and steroid derivatives in Solanaceous plants following stresses imposed by wounding and pathogen infection. To better understand this complex step in stress-responsive isoprenoid synthesis, we isolated three classes of cDNAS encoding HMGR (hmg1, hmg2, and hmg3) from a potato tuber library using a probe derived from an Arabidopsis HMGR cDNA. The potato cDNAs had extensive homology in portions of the protein coding regions but had low homology in the 3' untranslated regions. RNA gel blot analyses using gene-specific probes showed that hmg1 was strongly induced in tuber tissue by wounding, but the wound induction was strongly suppressed by treatment of the tissue with the fungal elicitor arachidonic acid or by inoculation with an incompatible or compatible race of the fungal pathogen Phytophtora infestans. The hmg2 and hmg3 mRNAs also accumulated in response to wounding, but in contrast to hmg1, these mRNAs were strongly enhanced by arachidonic acid or inoculation. Inoculation with a compatible race of P. infestans resulted in similar patterns in HMGR gene expression of hmg2 and hmg3 except that the magnitude and rate of the changes in mRNA levels were reduced relative to the incompatible interaction. The differential regulation of members of the HMGR gene family may explain in part the previously reported changes in HMGR enzyme activities following wounding and elicitor treatment. The suppression of hmg1 and the enhancement of hmg2 and hmg3 transcript levels following elicitor treatment or inoculation with the incompatible race parallel the suppression in steroid and stimulation of sesquiterpenoid accumulations observed in earlier investigations. The results are discussed in relation to the hypothesis that there are discrete organizational channels for sterol and sesquiterpene biosynthesis in potato and other Solanaceous species.

Amino Acid Sequence↗
PubMed1992

Sandwich capture ELISA by a murine monoclonal antibody against a genus-specific LPS epitope for the detection of different common serotypes of salmonellas.

A sandwich capture ELISA based on a murine monoclonal antibody against a genus-specific epitope in the outer core region of the Salmonella lipopolysaccharide is described for the detection of different common serotypes of salmonellas. Four h broth cultures of seven standard and 24 wild strains of salmonellas were all detected by the capture ELISA while overnight broth cultures of 21 non-salmonella standard strains were all negative. The capture ELISA detected 1 ng/ml of Ra lipopolysaccharide, 10(6)/ml of a smooth wild strain of Salm. typhimurium, and 1120 cells of Salm. heidelberg after enrichment culture for 4 h.

Animals↗
PubMed1992

Violence as a public health priority for black Americans.

This study investigated the extent to which black public health and political leaders believe that reducing violence should be a national public health priority for black Americans when compared with other public health problems such as acquired immunodeficiency syndrome, low birthweight, and access to health care. A survey asking whether violence in the black community is amendable to change and who (or what institutions) should be responsible for the reduction of violence was sent to 427 black health leaders, 326 black mayors, and 467 black legislators. Three hundred twenty responses were returned. Virtually all respondents placed violence as one of the top five, if not the highest, public health priority for black Americans. Health and political leaders differed in their beliefs about whether violence and violence-related behaviors can be ameliorated, and who should bear responsibility for the reduction of violence. While this survey had limitations, more than 300 black public health and political leaders indicated that violence among black Americans should be made a national public health priority. Policy implications are discussed, and a proactive role for the National Medical Association is advocated.

Black or African American↗
PubMed1992

Childhood and young adult cancer in New Jersey.

Cancer incidence rates for 0 to 24 years of age were examined for New Jersey for 1979-1985. New Jersey rates generally were higher than the comparison states. They were most like those of Connecticut, the state most similar in demographics, geography, and degree of urbanization.

Adolescent↗
PubMed1991

Characterization and application of a murine monoclonal antibody that reacts specifically with the serogroup D1 Salmonella.

A murine hybridoma cell line that produces monoclonal antibody (mAb) against the serogroup D1 Salmonella lipopolysaccharide (LPS) antigen was established. The trisaccharide tyvelose alpha 1----3 mannose alpha 1----4 rhamnose was shown to be involved in the reactive epitope of the mAb since this mAb reacted strongly with strains of serogroup D1 Salmonella but not with Salmonella strains from the O serogroups of A, B, and D2, and sodium meta-periodate was found to destroy the reactivity of the serogroup D1 O-antigen with the mAb. As such this mAb was found to be a useful serotyping reagent for the identification of serogroup D1 Salmonella, and for the differentiation of strains of serogroups D1 and D2 Salmonella which have identical flagellar H antigens.

Animals↗