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Biomedical subjects

Y C Su

Publications and source records attributed to Y C Su.

At least 37 records · Page 2Linked to original sources

Influence of milk centrifugation, brining and ripening conditions in preventing gas formation by Clostridium spp. in Gouda cheese.

This study examined milk centrifugation, increased salt concentration, and low ripening temperature as potential strategies to prevent late blowing caused by gas-forming Clostridium spp. in Gouda cheese. The survival of clostridia spores in cheese brine and their ability to enter Gouda cheese during brining was also evaluated. Centrifugation (3000 x g for 30 s) of contaminated milk resulted in > 60% spore reduction, with increased spore reduction at greater centrifugal forces. Low levels of C. tyrobutyricum and C. sporogenes spores survived in saturated (23%, w/v) brine with 2% (v/v) added whey at 15 degrees C for 63 days, while C. beijerinckii and C. butyricum spores were not detectable on days 4 and 35, respectively. Spores of C. tyrobutyricum in brine infiltrated Gouda cheese during 2 h of brining at 13 degrees C resulted in production of small gas holes during ripening. In Gouda cheese slurry stored at 13 degrees C, three C. tyrobutyricum strains plus one of three C. sporogenes strains germinated in the slurry with no added salt. Of three C. tyrobutyricum strains stored at 13 degrees C in slurries with higher water-phase salt concentrations of 2.4 and 3.6%, two strains and one strain germinated, respectively. No germination of spores was detected in any cheese slurry stored at 5 or 8 degrees C. Milk centrifugation, increased percent water-phase salt, absence of spores in brine, and decreased ripening temperature are all potentially important measures against gas production by Clostridium spp. in Gouda cheese.

Animals↗

Tamoxifen decreases renal inflammation and alleviates disease severity in autoimmune NZB/W F1 mice.

It has been documented that sex hormone may play a role in the pathogenesis of murine lupus. To determine the effect of tamoxifen (TAM) on NZB/W F1 female mice, a total dose of 800 microg (22 mg/kg body weight) of TAM was administered subcutaneously every 2 weeks. The control mice were injected with peanut oil only. After treatment with TAM for 5 months, the mice were killed and immunological parameters were evaluated. The results suggest that NZB/W F1 mice treated with TAM had less severe proteinuria and increased survival rate compared to controls. Flow cytometric analysis of splenocytes revealed a significantly lower percentage of B cells and CD5+ B cells in the TAM-treated group. There was a significantly lower serum level of soluble tumour necrosis factor (TNF) receptor I and II molecules in the TAM-treated mice. Immunohistological study showed that control mice had severe immune complex deposition in the kidney. In contrast, TAM-treated mice had much less pathological change. In summary, this study demonstrated that TAM treatment might be able to alleviate the symptoms of lupus nephritis, influence B-cell count, modulate the expression of cytokine receptors and thereby subsequently affect immune function. Further studies to determine the cellular mechanisms in lupus nephritis may increase our understanding of this complex disease and provide additional targets for therapeutic intervention.

Animals↗

The stimulation of antral motility by erythromycin is attenuated by hyperglycemia.

OBJECTIVE: Diabetic gastroparesis is usually treated with prokinetic drugs, of which the most potent, when given intravenously during euglycemia, is erythromycin. Recent studies have demonstrated that the gastrokinetic effects of erythromycin are attenuated by hyperglycemia. The aim of this study was to determine whether the effects of erythromycin on antropyloroduodenal motility, including the organization of antral pressure waves, are modified by hyperglycemia. METHODS: A total of eight healthy male volunteers (median age 24 yr) were studied on 2 days each in randomized order. A manometric assembly, incorporating six antral, two pyloric, and seven duodenal sideholes and a pyloric sleeve sensor, was positioned with the sleeve spanning the pylorus. The blood glucose concentration was stabilized at about 5 mmol/L (euglycemia) or 15 mmol/L (hyperglycemia). After 30 min (T = 0), an intraduodenal lipid infusion (1.5 kcal/min) was commenced and continued until the end of the study. At T = 20 minutes, erythromycin (200 mg) as the lactobionate was infused intravenously over 20 min, followed by 100 mg over the next 40 min. RESULTS: Intravenous erythromycin increased the amplitude of antral waves during intraduodenal lipid infusion at both blood glucose concentrations (p < 0.01 for euglycemia and p < 0.05 for hyperglycemia). After erythromycin (T = 20 to T = 80), the frequency (p < 0.05) and amplitude (p < 0.01) of antral waves were less during hyperglycemia than euglycemia. Both propagated (p < 0.0005) and nonpropagated (p < 0.01) antral waves were decreased by hyperglycemia, but the suppression of propagated waves was greater (p < 0.05). Erythromycin reduced the frequency (p = 0.09) but increased the amplitude (p < 0.05) of phasic pyloric pressures, and decreased basal pyloric pressure (p < 0.0005). The frequency (p = 0.06) and amplitude (p < 0.05) of phasic pyloric waves during erythromycin infusion were slightly less during hyperglycemia than euglycemia, whereas there was no effect of the blood glucose concentration on basal pyloric pressure. Erythromycin increased the amplitude (p < 0.001) but not the frequency of duodenal waves; the frequency and amplitude of duodenal waves did not differ between the two blood glucose concentrations. CONCLUSIONS: Hyperglycemia attenuates the stimulation of antral pressures and propagated antral sequences by erythromycin, but not the effects of erythromycin on pyloric or duodenal motility.

Adolescent↗

The association between Helicobacter pylori infection and functional dyspepsia in patients with irritable bowel syndrome.

OBJECTIVE: Irritable bowel syndrome (IBS) is associated with an exaggerated response to a variety of physiological and nonphysiological gastrointestinal stimuli. Many patients with IBS also have functional dyspepsia. Our aim was to examine the hypothesis that Helicobacter pylori (H. pylori) infection may predispose IBS patients to functional dyspepsia. METHODS: In 69 IBS patients, dyspeptic symptoms, H. pylori status, and sociodemographic and psychological variables (perceived stress, trait anxiety, and depression) were assessed. Sociodemographic and psychological variables were also evaluated in 52 control subjects. RESULTS: Mean scores for perceived stress (17.1 +/- 6.0 vs 14.9 +/- 6.0, p = 0.05), trait anxiety (45.6 +/- 9.1 vs 41.1 +/- 7.8, p = 0.004) and depression (9.9 +/- 8.4 vs 5.0 +/- 5.5, p = 0.0002) were higher in IBS patients than in controls. In all, 33 of the 69 patients (47.8%) had H. pylori infection, and this was associated with relevant symptoms of epigastric pain (odds ratio [OR] = 6.77, 95% confidence interval [CI] 1.89-24.3) and postprandial upper abdominal fullness (OR = 4.23, 95% CI 1.38-13.2). H. pylori infection and female gender were independent predictors of the presence of relevant dyspepsia (OR = 8.31, 95% CI 2.35-29.5 and 6.06, 95% CI 1.71-21.5, respectively). Symptom intensity was associated with the level of perceived stress (total relevant symptom number > or =3 vs <3, OR = 1.16 per point on a 40-point perceived stress scale, 95% CI 1.01-1.34). CONCLUSIONS: In IBS patients, the presence of dyspepsia is associated with H. pylori infection, female gender, and perceived stress.

Adult↗

The Ste20 kinase misshapen regulates both photoreceptor axon targeting and dorsal closure, acting downstream of distinct signals.

We have previously shown that the Ste20 kinase encoded by misshapen (msn) functions upstream of the c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase module in Drosophila. msn is required to activate the Drosophila JNK, Basket (Bsk), to promote dorsal closure of the embryo. A mammalian homolog of Msn, Nck interacting kinase, interacts with the SH3 domains of the SH2-SH3 adapter protein Nck. We now show that Msn likewise interacts with Dreadlocks (Dock), the Drosophila homolog of Nck. dock is required for the correct targeting of photoreceptor axons. We have performed a structure-function analysis of Msn in vivo in Drosophila in order to elucidate the mechanism whereby Msn regulates JNK and to determine whether msn, like dock, is required for the correct targeting of photoreceptor axons. We show that Msn requires both a functional kinase and a C-terminal regulatory domain to activate JNK in vivo in Drosophila. A mutation in a PXXP motif on Msn that prevents it from binding to the SH3 domains of Dock does not affect its ability to rescue the dorsal closure defect in msn embryos, suggesting that Dock is not an upstream regulator of msn in dorsal closure. Larvae with only this mutated form of Msn show a marked disruption in photoreceptor axon targeting, implicating an SH3 domain protein in this process; however, an activated form of Msn is not sufficient to rescue the dock mutant phenotype. Mosaic analysis reveals that msn expression is required in photoreceptors in order for their axons to project correctly. The data presented here genetically link msn to two distinct biological events, dorsal closure and photoreceptor axon pathfinding, and thus provide the first evidence that Ste20 kinases of the germinal center kinase family play a role in axonal pathfinding. The ability of Msn to interact with distinct classes of adapter molecules in dorsal closure and photoreceptor axon pathfinding may provide the flexibility that allows it to link to distinct upstream signaling systems.

Adaptor Proteins, Signal Transducing↗

The effect of fasting on the pulse spectrum.

Nutrition is the major source of bioenergy. The present study investigated the physiological response to fasting by analyzing the effect of fasting on the pulse spectrum of the radial artery. Sixteen subjects were allowed to take only mineral water for 24 hours, and the pulse was measured at intervals during fasting and after eating resumed. Data were analyzed using one-way analysis of variance (ANOVA) with Scheffe's test for pairwise comparisons. The results indicate the second harmonic of the radial pulse increased and the sixth harmonic decreased significantly after 24 hours of fasting. The proportions of the second harmonic then decreased significantly and those of the sixth harmonic increased significantly 12 hours after eating resumed. These findings suggest that a rhythm exists in physiological changes and the distribution of bioenergy, which ensures that the overall heart load will remain unchanged during the fasting and re-feeding periods, maintaining a stable overall balance in body function.

Adult↗

A Drosophila TNF-receptor-associated factor (TRAF) binds the ste20 kinase Misshapen and activates Jun kinase.

Two families of protein kinases that are closely related to Ste20 in their kinase domain have been identified - the p21-activated protein kinase (Pak) and SPS1 families [1-3]. In contrast to Pak family members, SPS1 family members do not bind and are not activated by GTP-bound p21Rac and Cdc42. We recently placed a member of the SPS1 family, called Misshapen (Msn), genetically upstream of the c-Jun amino-terminal (JNK) mitogen-activated protein (MAP) kinase module in Drosophila [4]. The failure to activate JNK in Drosophila leads to embryonic lethality due to the failure of these embryos to stimulate dorsal closure [5-8]. Msn probably functions as a MAP kinase kinase kinase kinase in Drosophila, activating the JNK pathway via an, as yet, undefined MAP kinase kinase kinase. We have identified a Drosophila TNF-receptor-associated factor, DTRAF1, by screening for Msn-interacting proteins using the yeast two-hybrid system. In contrast to the mammalian TRAFs that have been shown to activate JNK, DTRAF1 lacks an amino-terminal 'Ring-finger' domain, and overexpression of a truncated DTRAF1, consisting of only its TRAF domain, activates JNK. We also identified another DTRAF, DTRAF2, that contains an amino-terminal Ring-finger domain. Msn specifically binds the TRAF domain of DTRAF1 but not that of DTRAF2. In Drosophila, DTRAF1 is thus a good candidate for an upstream molecule that regulates the JNK pathway by interacting with, and activating, Msn. Consistent with this idea, expression of a dominant-negative Msn mutant protein blocks the activation of JNK by DTRAF1. Furthermore, coexpression of Msn with DTRAF1 leads to the synergistic activation of JNK. We have extended some of these observations to the mammalian homolog of Msn, Nck-interacting kinase (NIK), suggesting that TRAFs also play a critical role in regulating Ste20 kinases in mammals.

Amino Acid Sequence↗

Endoscopic hydrogen peroxide spray may facilitate localization of the bleeding site in acute upper gastrointestinal bleeding.

BACKGROUND AND STUDY AIMS: A major problem encountered in the emergency endoscopic management of acute upper gastrointestinal (UGI) bleeding is poor localization of the bleeding site, which can be obscured by blood or clots. Traditional attempts to overcome this problem have been by physical methods, which have usually proved unsatisfactory. The aim of this prospective study was to show that hydrogen peroxide can be used as a dissolution agent, resulting in an alteration of the characteristics of blood clots and allowing a clearer visual field. PATIENTS AND METHODS: Twenty patients with acute UGI bleeding (13 male, seven female) were included in the study. The suspected site of bleeding was initially sprayed with 200 ml of saline and then with 25-175 ml of 3 % H2O2. Pictures of the visual field were taken before and after irrigation with both saline and H2O2. These pictures were evaluated by three gastroenterologists and scored using the following visual clearance scoring system: -3, marked worsening of visual field; -2, moderate worsening; -1, slight worsening; 0, no change; +1, slight improvement; +2, moderate improvement; + 3, marked improvement. In cases of active oozing or spurting, after initial hemostasis was achieved the bleeding point was injected with pure ethanol or cauterized with a heater probe. In order to assess the safety of 3 % H2O2 endoscopic biopsies of the antrum and the duodenal bulb were performed before and 30 minutes after its use and examined by a pathologist. RESULTS: There was a significant improvement in the mean visual clearance score after irrigation with H2O2 compared to irrigation with saline alone (2.13 vs. 0.43, P<0.001). During endoscopic examination there were 19 patients with active oozing from the ulcer base covered by an adherent blood clot; 12 of these (63.1%) achieved initial hemostasis after H2O2 spraying. Eleven of 18 (61.1 %) patients complained of a mild epigastric burning sensation during H2O2 irrigation. There was no clinically significant change in the histology of the antrum and the duodenal bulb after H2O2 therapy. CONCLUSIONS: We concluded that H2O2 is a safe and effective way to clear the visual field, facilitating the localization of the bleeding site during emergency endoscopy for acute UGI bleeding, with only mild side effects. In some cases H2O2 therapy can also induce temporary hemostasis. We recommended the use of hydrogen peroxide to improve endoscopic visualization, especially in cases where an adherent blood clot covers the suspected bleeding site.

Adult↗

Heterogeneous Helicobacter pylori isolates from H. pylori-infected couples in Taiwan.

Helicobacter pylori strain diversity was investigated in 55 H. pylori seropositive couples in Taiwan in biopsy samples from the antrum and corpus. Two DNA typing methods were used to characterize 90 isolates from 25 couples. In only 1 of the 25 couples was the same strain colonized from both partners. Comparison of isolates from 2 sites in each of 40 patients showed that 9 pairs were distinct but might be related. Peptic ulcer occurred in 77.8% of these 9 patients compared with 29% of 31 patients with the same predominant strain in 2 biopsies (P=.025). Random amplified polymorphic DNA and sequence analyses of 2 closely related isolates from 1 patient support the hypothesis that development of genetic diversity of H. pylori results from horizontal genetic exchange during long-term colonization of mixed bacterial populations.

Adult↗

The hemodynamic changes of gastroduodenal regional blood flow after Helicobacter pylori eradication in patients with duodenal ulcer scar.

Duodenal ulcer (DU) is frequently accompanied by Helicobacter pylori (Hp) infection and associated with the imbalance of aggressive factors and defensive factors. To investigate the possible relationship between Hp and regional gastric blood flow, 26 endoscopically proved DU (scar stage) and Hp infection patients were included and received triple therapy (colloid bismuth subcitrate 120 mg qid for 4 weeks, amoxicillin 500 mg qid for 2 weeks and metronidazole 250 mg tid for 2 weeks). Regional gastroduodenal blood flow (RGDF) was measured at DU scar area and antrum lesser curvature site by laser Doppler flowmetry during endoscopic examination, before and one month after triple therapy. In 22 patients with Hp eradication the RGDF was significantly elevated at antrum lesser site after triple therapy (p < 0.05) but there was no difference at DU scar area. However, in 4 patients without Hp eradication no difference of RGDF in these two points was found. Therefore, Hp appears to have direct effects on gastric microcirculation.

Adult↗

Salmonella choleraesuis bacteremia in southern Taiwan.

Within a 6-year period from January 1991 to December 1996, 19 patients with Salmonella choleraesuis bacteremia were enrolled for clinical and microbiological analysis. Young children, the elderly and patients with hematological malignancy (36.8%), liver cirrhosis (26.3%), systemic lupus erythematosus (10.5%), chronic renal impairment (10.5%), and peptic ulcer (10.5%) were at high risk of this infection. The ratio of male to female was 3:1. Three cases (15.8%) were nosocomially acquired. Fever (89.5%), chills (57.9%) and anorexia (52.6%) were the most common clinical manifestations. Seven patients (36.8%) presented no gastrointestinal manifestations. Normal white blood cell count was noted in seven patients (36.8%), and neutropenia caused by underlying diseases or severe infection was found in six cases (31.6%). Various types of metastatic focal infections were found, such as septic arthritis, cutaneous infection, spontaneous bacterial peritonitis, and pneumonia. The severe immunocompromised status of patients and the high virulence of this pathogen may contribute to the high case fatality rate (21%). Higher resistance rate to commonly used antimicrobial agents was noted in ampicillin (94.7%), chloramphenicol (89.5%), and TMP/SMZ (63.8%). All strains of S. choleraesuis were susceptible to third-generation cephalosporins and fluoroquinolones. Generally, S. choleraesuis bacteremia should be taken into account in the differential diagnosis of sepsis in immunocompromised patients, even without gastrointestinal manifestations. The third-generation cephalosporins and fluoroquinolones may be the first choice for treatment of this invasive infections.

Adolescent↗

The Drosophila Ste20-related kinase misshapen is required for embryonic dorsal closure and acts through a JNK MAPK module on an evolutionarily conserved signaling pathway.

Dorsal closure in the Drosophila embryo occurs during the later stages of embryogenesis and involves changes in cell shape leading to the juxtaposition and subsequent adherence of the lateral epidermal primordia over the amnioserosa. Dorsal closure requires the activation of a conserved c-jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) module, as it is blocked by null mutations in JNK kinase [hemipterous (hep)] and JNK [basket (bsk)]. Drosophila JNK (DJNK) functions by phosphorylating and activating DJun, which in turn induces the transcription of decapentaplegic (dpp). We provide biochemical and genetic evidence that a Ste20-related kinase, misshapen (msn), functions upstream of hep and bsk to stimulate dorsal closure in the Drosophila embryo. Mammalian (NCK-interacting kinase [NIK]) and Caenorhabditis elegans (mig-15) homologs of msn have been identified; mig-15 is necessary for several developmental processes in C. elegans. These data suggest that msn, mig-15, and NIK are components of a signaling pathway that is conserved among flies, worms, and mammals to control developmentally regulated pathways.

Amino Acid Sequence↗

Production of staphylococcal enterotoxin H under controlled pH and aeration.

The effects of controlled pH and aeration on the growth of Staphylococcus aureus strain FRI-569 and production of enterotoxin H (SEH) were studied. S. aureus FRI-569 did not grow well anaerobically. Aeration permitted better growth of cells especially at a flow rate of 300 cc/min. The optimal pH for S. aureus FRI-569 growth was 7.0, with less growth being observed at pH 6.5 and 7.5 or with no pH control. Very little SEH (< 21 ng/ml) was produced by S. aureus strain FRI-569 under anaerobic incubation. High SEH production was observed with aeration at 300 cc/min. Increasing aeration to 400 cc/min or decreasing it to 200 cc/min resulted in reduced SEH production. Larger amounts of SEH were produced when the pH was controlled at 7.0, while maintaining the pH at 6.5 or 7.5 resulted in lower levels of SEH being produced. However, the amounts were still greater than those observed when the pH was not controlled.

Aerobiosis↗

[Group psychotherapeutic factors in a self-assertive group].

The technique of group psychotherapy has recently been introduced to the practice in self-assertiveness training group. This study aims to assess various group factors that are hypothesized to be effective in the group process in a self-assertive group. Subjects of the study were participants in a 13-member self-assertiveness training group, with 4 female nurses and 8 male employees and 1 male student. The average age of this group was 35.2 years. Assessment of the group was based on Yalom's concept of twelve therapeutic factors in the group process. The results showed that 'identification', 'The existential factor' and 'interpersonal learning-input' were the three most important factors demonstrated during the group process. There were no significant age and gender differences in the above 'identification' and 'existential' factors. However, different beneficial factors were found for each group: for subjects aged 40 and above and males, it was 'interpersonal learning-output'; while in those with aged under 40 and females, 'universality' was more important than 'interpersonal learning-input'. Comparison of therapeutic factors among different groups was attempted. The above results were found different from patient groups, or the groups of university students. The discrepancy is due to different composition and tasks of each group.

Adult↗

NIK is a new Ste20-related kinase that binds NCK and MEKK1 and activates the SAPK/JNK cascade via a conserved regulatory domain.

Nck, an adaptor protein composed of one SH2 and three SH3 domains, is a common target for a variety of cell surface receptors. We have identified a novel mammalian serine/threonine kinase that interacts with the SH3 domains of Nck, termed Nck Interacting Kinase (NIK). This kinase is most homologous to the Sterile 20 (Ste20) family of protein kinases. Of the members of this family, GCK and MSST1 are most similar to NIK in that they bind neither Cdc42 nor Rac and contain an N-terminal kinase domain with a putative C-terminal regulatory domain. Transient overexpression of NIK specifically activates the stress-activated protein kinase (SAPK) pathway. Both the kinase domain and C-terminal regulatory region of NIK are required for full activation of SAPK. NIK likely functions upstream of MEKK1 to activate this pathway; a dominant-negative MEK kinase 1 (MEKK1) blocks activation of SAPK by NIK. MEKK1 and NIK also associate in cells and this interaction is mediated by regulatory domains on both proteins. Two other members of this kinase family, GCK and HPK1, contain C-terminal regulatory domains with homology to that of NIK. These findings indicate that the C-terminal domain of these proteins encodes a new protein domain family and suggests that this domain couples these kinases to the SAPK pathway, possibly by interacting with MEKK1 or related kinases.

Adaptor Proteins, Signal Transducing↗

[Job strain, social support and mental health: a study on the male heavy manufacturing workers].

OBJECT: The aim of this study is to explore the influence of work experience on workers' psychological function. Specifically, the researchers will examine the effect of job demand, decision latitude, job strain, and social support at worksite on the mental health status of male heavy manufacturing workers. METHOD: By purposive sampling, from October 1994 to March 1995, the present investigators implemented a self-administered questionnaire survey on the workers in southern Taiwan. The Karasek job strain model and its measure were embedded in the questionnaire to evaluate workers' perceptions of their job conditions. In addition, Chinese Health Questionnaire (CHQ) was utilized to evaluate the workers' status of mental health. RESULT: Totally, 1,117 workers were selected for this survey. An unviriate analysis showed the younger the workers, the lower their monthly income, and the newer their employment, were more likely to be classified as high risk in mental health status. The workers with more decision latitude and higher social support would be better in mental health status. In addition, it also showed that workers under high job strain were more likely to be in poor mental health status. Result from multivariate logistic regression showed those who served longer, had more decision automony, and had higher social support, were less likely to be in poor mental health status. Instead, those who sustained high job strain were more likely to be in poor mental health status. DISCUSSION: The implication from those findings for the implementation of health promotion program. would be raised, and the limitation of this inference would also be discussed.

Adolescent↗

Protein tyrosine phosphatase activities are involved in apoptotic cancer cell death induced by GL331, a new homolog of etoposide.

GL331 is a semisynthetic topoisomerase II inhibitor derived from a plant toxin podophyllotoxin. In 72-h exposure assays, LD50 values of GL331 range from 0.5 to 2 microM, which are three- to ten-fold lower than those of its homologous compound etoposide (VP-16), depending on different cancer cell lines including nasopharyngeal, hepatocellular, gastric, cervical and colon cancer types. Apoptotic DNA ladders could be detected when cancer cells were treated with GL331 for 24 h even if the Bcl-2 and Bax protein levels were not altered during the period. Besides acting as topoisomerase II inhibitors, both GL331 and VP-16 decrease the cellular protein tyrosine kinase (PTK) activities in cancer cells. The activities of protein tyrosine phosphatase (PTP) are significantly increased after GL331 treatment but are not affected by VP-16. GL331-induced internucleosomal cleavage can be efficiently prevented by two inhibitors of PTP, sodium orthovanadate and zinc chloride, but not by okadaic acid, which inhibits serine/threonine phosphatase activity. These results indicate that GL331 may induce apoptotic cell death, and that activation of protein tyrosine phosphatases may be involved in this process.

Antineoplastic Agents, Phytogenic↗