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Biomedical subjects

J Hong

Publications and source records attributed to J Hong.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Effect of intrahippocampal microinjection of enkephalin on cellular immune function and brain IL-1 alpha gene expression in rat].

The effect of intrahippocampal microinjection of enkephalin on cellular immune function and hippocampal IL-1 alpha gene expression was studied in rats. The results showed that: (1) The proliferation activity of splenic lymphocytes stimulated by Con A was significantly increased with microinjection of Leu-enkephalin 1 microliter (18 mmol/L) or Met-enkephalin 1 microliter (18 mmol/L) into bilateral hippocampus, but was inhibited by Lipopolysaccharide 1 microliter (50 ng/microliter). The proliferative response of splenic lymphocytes to Leu-enkephalin still persisted after bilateral adrenalectomy. Low doses of Leu- or Met-enkephalin (10(-10), 10(-11) mol/L) were also capable of causing proliferative activity of the Con A- stimulated cultured splenic lymphocytes in vitro. (2) Using RT-PCR technique, IL-1 alpha gene expression was detected in hippocampus 90 min after bilateral intrahippocampal injection of LPS. The LPS-induced IL-1 alpha gene expression in hippocampus could no longer be detected 30 min after microinjection of Met- or Leu-enkephalin into hippocampus. The above results suggested that intrahippocampal enkephalin might play an important role in neuro-immunomodulation by enhancing the inhibition of IL-1 alpha gene expression in hippocampal formation.

Adrenalectomy↗
PubMed1995

Estimation of kinetics of mercury detoxification from low-inoculum batch cultures of Pseudomonas aeruginosa PU21 (Rip64).

The growth rate of Pseudomonas aeruginosa PU21 (Rip64) and the mercury detoxification rate were determined by using low-inoculum batch cultures. In order to attain invariant culture conditions for the determination of growth kinetics in mercury-containing Pseudomonas minimal media (PMM), the initial cell concentrations were adjusted to approx. 100 cells per ml, and the initial mercury concentrations used were less than 2 micrograms Hg2+ per ml. It was found that the specific growth rate decreased as mercury concentration increased. The relationship between specific growth rate and glucose concentration was found to follow Monod kinetics. The mercury detoxification rate was determined for the viable cells and the dying (non-growing) cells.

Biotransformation↗
PubMed1995

Nucleotide sequence and tissue-specific expression of the multifunctional protein carbamoyl-phosphate synthetase-aspartate transcarbamoylase-dihydroorotase (CAD) mRNA in Squalus acanthias.

Carbamoyl-phosphate synthetase II (CPSase II), aspartate transcarbamoylase (ATCase), and dihydroorotase (DHOase) catalyze the first three steps of de novo pyrimidine nucleotide biosynthesis, respectively. In mammalian species, these three enzyme activities exist in the cytosol in liver and other tissues as a multifunctional complex on a single polypeptide called carbamoyl-phosphate synthetase-aspartate transcarbamoylase-dihydroorotase (CAD) in the order of NH2-CPSase II-DHOase-ATCase-COOH. Previous studies provided evidence that in Squalus acanthias (spiny dogfish) these enzymes are not expressed in liver and that they exist as separate entities in the cytosol of extra-hepatic tissues such as testes and spleen (Anderson, P. M. (1989) Biochem. J. 261, 523-529). Here we report that the genes for these three enzymes are expressed in testes as a single transcript analogous to CAD in mammalian species and that these genes are not expressed in liver at levels that can be detected by Northern blots or by the polymerase chain reaction. The absence of the pyrimidine pathway in the liver may be related to the exclusive localization of glutamine synthetase in the mitochondrial matrix which provides for efficient assimilation of ammonia as glutamine for urea synthesis in these ureoosmotic species; thus glutamine may not be available for CPSase II or other amidotransferase activities in the cytosol. The amino acid sequence deduced from the nucleotide sequence of the shark CAD cDNA reported here is very similar to CAD from other species; alignment with the hamster CAD sequence shows 77% identical residues.

Amino Acid Sequence↗
PubMed1995

Cross-national comparisons of ageing mothers of adults with intellectual disabilities.

Ageing (55+ years) mothers of adults with intellectual disabilities in the Republic of Ireland, Northern Ireland and the United States were compared with respect to three general issues. Firstly, to what extent do the adults in these three countries differ in their level of reliance on their mothers? Secondly, do the mothers differ in the extent to which they have made plans for the future care of their son or daughter with intellectual disabilities? Thirdly, do the mothers differ in physical, social and psychological well-being? These cross-national comparisons were undertaken to examine the extent to which lifelong caregiving has either a common influence on mothers across national boundaries, or, alternatively, whether the cultural context exerts a unique influence on mothers in each country. Findings supported the latter explanation, even when background characteristics were statistically controlled.

Adult↗
PubMed1995

Salmonella typhimurium pgtB mutants conferring constitutive expression of phosphoglycerate transporter pgtP independent of pgtC.

PgtC is one of the three components of the atypical "two-component" pgt regulatory system. To investigate whether functional PgtC required for the induction of pgtP expression could be bypassed in the signal transduction process, we sought, and succeeded in isolating, intergenic suppressors arising in the low-copy mini-F plasmid, pSJ11, bearing the entire pgt system except for a 168-bp deletion near the end of the pgtC gene. By transport assays, these suppressors were found to confer constitutive pgtP expression. Intriguingly, all five mutations reside near the 5' end of the pgtB gene, at codons 19 and 21. One mutation alters Arg-19 to Gln, two alter Ala-21 to Thr, one alters Ala-21 to Val, and one alters Ala-21 to Ile. Appropriate strains in which the pgtP promoter was fused to lacZ and which bore the pgtB mutations with and without mutations in pgtC and pgtA genes were constructed, and the epistatic relationships of the wild-type pgtC allele, a mutant pgtA allele, and an essentially total deletion of pgtC to the constitutive pgtB mutations were determined. In the mutant strains bearing the Ala-21 --> Ile and Ala-21 --> Val substitutions, the level of constitutive pgtP-lacZ reporter expression was not affected by the presence of the wild-type pgtC allele, nor was it affected by the total absence of PgtC in the case of the Ala-21 --> Val alteration examined; however, in the mutant strains bearing the Ala-21 --> Thr and the Arg-19 --> Gln substitutions, the extent of constitutive pgtP-lacZ reporter expression was markedly enhanced by the presence of wild-type pgtC allele and, in the case of the Arg-19 -->Gln change examined, by the total absence of PgtC as well. These results indicate that PgtC contains no domain necessary for the kinase activity; that PgtB can be activated in the absence of PgtC mutational alterations of the protein itself; and that PgtB and PgtC interact in the signaling process, with PgtC functioning to activate and modulate the kinase activity of Pgtb. In all strains, the replacement of the wild type pgtA allele with a mutant pgtA allele completely abolished expression of the pgtP-lacZ reporter, indicating that functional pgtA is essential for the constitutivity. His-457 of PgtB, a potential site of autophosphorylation, is also required for the constitutivity because its change to Val drastically reduced pgtP-lacZ reporter expression. The structural basis for the activation of the altered PgtB is discussed in terms of putative structure of PgtB in the membrane.

Amino Acid Sequence↗
PubMed1995

Breastfeeding practices in Chengdu, Sichuan, China.

Barriers to increased breastfeeding rates in Chengdu, Sichuan were investigated in 1992 and 1993. Responses of focus groups showed that ignorance about breastfeeding and belief that the mother's milk was inadequate, and lack of support from their families, places of employment, and the health system acted as barriers to the women's breastfeeding their infants up to the age of four to six months. Subsequently, 363 mothers of 4- to 12-month-old Chengdu infants were surveyed. Although most mothers in both studies said breastmilk was the best food for their infant up to age of four to six months, only about half of the mothers breastfed for longer than one month. Both studies showed that infants who roomed with their mothers after birth were more likely to have been put to their mother's breast earlier, fed colostrum, breastfed somewhat longer, and exclusively breastfed for a somewhat longer period, although their mothers' infant feeding knowledge did not differ. The researchers conclude that Chengdu health workers should teach parents and parents-to-be more about breastfeeding, and that rooming-in be expanded in Chengdu hospitals.

Breast Feeding↗
PubMed1995

Four outbreaks of human trichinellosis in Henan Province.

Four outbreaks of human trichinellosis caused by eating pork together had occurred successively in two rural areas and two cities of Henan Province, where the disease is endemic. Of the 110 persons involved, 54 had the onset. All of them had the history of eating pork. In the outbreak of Dengzhou, in those persons who dined together, men were all uninfected and 13 women were infected. The difference found between sexes was suggested to be related with spirit drinking. In these 54 patients, the latent period ranged from 3 to 28 days. The relevant clinical symptoms and signs were fever, edema, myalgia, rash, headache, nausea, abdominal pain and diarrhea. Vomiting was uncommon. Most patients were hospitalized and all cases recovered in two weeks after proper treatment with albendazole.

Animals↗
PubMed1995

The psychological consequences of multiple roles: the nonnormative case.

Occupying multiple roles has been shown to be a major predictor of psychological well-being. We investigated the effects of multiple roles in the nonnormative case: a sample of aging mothers of adult children with mental retardation. These women have been in the role of caregiver for up to five decades, in addition to occupying the range of roles normatively held in adulthood and old age. We found, using longitudinal analyses, that holding multiple roles in significantly and negatively related to depression in this sample, as in the general population. The effect of multiple roles remains significant even after the previous level of depression is controlled. These results support the role accumulation hypothesis predicting positive consequences of multiple roles on psychological well-being, even in this sample of older women who have had lifelong caregiving responsibilities.

Adaptation, Psychological↗
PubMed1994

Carbamyl phosphate synthetase III, an evolutionary intermediate in the transition between glutamine-dependent and ammonia-dependent carbamyl phosphate synthetases.

The amino acid sequence of carbamyl phosphate synthetase (CPS) III from liver of spiny dogfish shark Squalus acanthias was deduced from the nucleotide sequence of its cDNA. Alignment of the derived amino acid sequence of CPS III with sequences of rat and frog CPS I and hamster CPS II reveals a high degree of amino acid identity, indicating that CPS III shares the same common ancestral genes as CPSs I and II. All of the CPSs examined show a high conservation of sequences in the adenine nucleotide binding domains and in residues that have been implicated in catalysis. The active-site cysteine residue required for glutamine-dependent activity by CPS II is preserved in the sequence of CPS III. Nevertheless, analysis of the protein sequences indicates that CPS III is more closely related to CPS I than to CPS II. The structure of CPS III, which is composed of a single polypeptide, is consistent with the view that CPS III evolved by fusion of separate genes coding for the glutaminase and synthetase domains of the enzyme and, like other CPSs, the synthetase domain evolved by duplication and fusion of an ancestral kinase gene. These results, together with the recent finding that frog CPS I retains the active site cysteine residue in the glutaminase domain required for glutamine-dependent activity, indicate that other amino acid substitutions critical for glutamine-dependent activity preceded loss of this catalytic cysteine residue. The results described here together with earlier biochemical evidence support the view that acetylglutamate and glutamine-dependent CPS III found in invertebrates and fish species represents an intermediate in the evolution of ancestral glutamine-dependent CPS II toward the acetylglutamate and ammonia-dependent CPS I of ureotelic terrestrial vertebrates.

Amino Acid Sequence↗
PubMed1994

cAMP, ethanol, and CO2 production with the addition of D-glucose anomer to starved yeast cells.

cAMP, ethanol, and CO2 production in starved yeast cells after the addition of D-glucose anomer was measured and compared over a wide range of anomer concentrations. At 1.0 g/l or higher concentrations, the addition of beta-D-glucose resulted in a higher cAMP peak. beta-D-glucose was more rapidly metabolized to ethanol and CO2 than alpha-D-glucose, although there was no notable difference in the uptake rates of the two anomers. At 0.4 g/l D-glucose anomer, the differences in cAMP and ethanol production rates for the two anomers were not significant. At 0.2 g/l D-glucose anomer or lower concentrations, ethanol production with alpha-D-glucose was higher than that with beta-D-glucose. The uptake rate of alpha-D-glucose was higher than that of beta-D-glucose at this low concentration.

Carbon Dioxide↗
PubMed1994

Tyrosinase production in recombinant E. coli containing trp promoter and ubiquitin sequence.

We have successfully expressed the active tyrosinase of Streptomyces antibioticus in Escherichia coli under the control of the trp promoter by fusing the sequence to the ORF438 gene. Because our attempt to connect the polycistronic gene of ORF438 and tyrosinase directly to the trp promoter of E. coli resulted in the expression of functionally inactive tyrosinase, we decided to fuse the COOH-terminus of ubiquitin sequence to the NH2-terminus of ORF438. Ubiquitin fusion has been shown to augment the yield of cloned gene products in E. coli by increasing the stability or translational efficiency of the fusion proteins. As a result, E. coli transformants harboring a plasmid pTRUBF that contains the ubiquitin-fused ORF438 and the tyrosinase gene produced the strong black pigment of melanin. About 300 units of tyrosinase per liter of batch culture were detected when cultivated in M9 medium containing casamino acids, L-tyrosine, and copper supplements. The black pigment, however, was not seen when grown in LB medium, suggesting that the trp promoter is well regulated. When recombinant E. coli cells grown in LB medium were transferred to a tryptophan-deficient minimal medium with phenol, we observed that phenol was removed from the solution, and the color of the medium turned black. This is due to the fact that the tyrosinase has polyphenol oxidase properties. We expect to use this recombinant E. coli for the waste treatment of phenolic compounds.

Base Sequence↗
PubMed1994

Bacterial translocation in mesenteric ischemia-reperfusion injury: is dysfunctional motility the link?

The authors previously reported that mesenteric ischemia and reperfusion (I/R) in a chronic newborn piglet model creates dysfunctional intestinal motility. Whether this leads to inadequate bacterial clearance and translocation (BT) through the gastrointestinal tract remains unclear. To test this hypothesis the authors used their chronic piglet model (weight, 3.5 +/- 0.3 kg; age, 18 +/- 4 days; on formula feeding); nonocclusive mesenteric ischemia was induced via reversible pericardial tamponade. Mesenteric flow (SMA Doppler measurement via the retroperitoneal approach) was decreased to 25% +/- 5% of baseline for 300 minutes in the ischemia group (n = 7) and followed by 14 hours of reperfusion in the I/R group (n = 6). Control subjects had a sham operation (n = 7). Mesenteric lymph nodes (MLN), liver (L), spleen (S), ileum, peritoneum, and blood were harvested for blind quantitative microbial analysis. Subjects in the control group had no cultures positive for growth. Eighty-five percent of animals in the ischemia group had positive MLN cultures only (P < .05 v control). All piglets in the I/R group had positive MLN cultures (P < .05 v control), and one third of them manifested bacteremia. Histological examination did not show mucosal disruption in any group. The validity of this model is confirmed by the negative cultures in the control group and by the presence of normal ileal flora in all animals. In the ischemia and I/R groups, MLN cultures were consistently positive with gram-negative bacilli (Escherichia coli and/or Klebsiella pneumoniae). When subjects of the I/R group had more than 1,000 colonies in the MLN, bacteremia with the translocating organisms was also identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Removal of intracanal obstructions with ultrasound. Analysis of 206 cases.

Intracanal obstructions were removed with ultrasound in 206 cases, with a success rate of 97.08%. Six cases (2.92%) failed owing to broken endodontic instruments at the apical third or in the curved and fine canals. The success rate of retrieval of casting post-core or other foreign objects was 100%. Our experience proves that ultrasonic technique is more effective and safer than any other methods for the removal of intracanal obstructions.

Adolescent↗
PubMed1993

Simultaneous analysis of 25 pesticides in crops using gas chromatography and their identification by gas chromatography-mass spectrometry.

The simultaneous analysis of 25 pesticides in soy beans and rices was performed by gas chromatography with dual electron-capture detection and nitrogen-phosphorus detection. The pesticides were extracted from the samples with solvent and the Bio-Beads S-X3 clean-up procedure was used. Recovery studies were performed at the 1-ppm level of pesticides added to each crop. Their recoveries ranged between 83 and 105% with coefficient of variations of 0.5-8.2%. The gas chromatographic properties of the 25 pesticides were also investigated. Conformation analysis was achieved by the retention time and characteristic fragment ions using the technique of gas chromatography-mass spectrometry-selected-ion monitoring.

Chromatography, Gas↗