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Z Yu

Publications and source records attributed to Z Yu.

At least 163 records · Page 9Linked to original sources
PubMed1999

Chronic and discrete stress as predictors of children's adjustment.

Diabetes, as a chronic stressor, and negative life events (NLEs), as a discrete stressor, were related to children's behavioral adjustment, along with moderating effects of the family environment. Diabetes and NLEs predicted both higher internalizing (INT) and externalizing (EXT) behavior problems, suggestive of nonspecific distress. Higher family conflict and lower cohesion each predicted more behavior problems (INT-EXT). However, conflict was the sole moderator of the stressors. Higher family conflict and diabetes exacerbated children's EXT behavior problems, with clinically elevated scores. Higher family conflict and higher NLEs resulted in clinically elevated INT-EXT behaviors. Conversely, low family conflict protected children's behavioral functioning from the stressors. Family cohesion was the sole predictor of children's social competencies but did not moderate the stressors.

Adaptation, Psychological↗
PubMed1999

Absence of mutations in the ATM gene in forty-seven cases of sporadic breast cancer.

Epidemiological evidence points to an increased risk of breast cancer in ataxia telangiectasia (AT) heterozygote women. Previous attempts to screen early onset or familial breast cancer patients failed to confirm an association. The issue of AT and late onset sporadic breast cancer remained unresolved. We screened 47 women who developed later onset, sporadic breast cancer for ataxia telangiectasia mutated (ATM) mutations. No mutations were found.

Adult↗
PubMed1999

Lessons learned from Sphingomonas species that degrade abietane triterpenoids.

Abietane terpenoid-degrading organisms include Sphingomonas spp which inhabit natural environments and biological treatment systems. An isolate from the high Arctic indicates that these organisms occur far from trees which synthesize abietanes and suggests that some of these organisms can occupy a niche in hydrocarbon-degrading soil communities. Abietane-degrading Sphingomonas spp provide additional evidence that the phylogeny of this genus is independent of the catabolic capabilities of its members. Studies of Sphingomonas sp DhA-33 demonstrate that biological treatment systems for pulp mill effluents have the potential to mineralize abietane resin acids. On the other hand, these studies indicate that some chlorinated dehydroabietic acids are quite recalcitrant. Strain DhA-33 grows relatively well on some chlorinated dehydroabietic acids but transforms others to stable metabolites. Using strain DhA-33, a novel method was developed to measure the metabolic activity of an individual population within a complex microbial community. Oligonucleotide hybridization probes were used to assay the 16S rRNA:rDNA ratio of DhA-33 as it grew in an activated sludge community. However, this method proved not to be sufficiently sensitive to measure naturally occurring resin acid-degrading populations. We propose that the same approach can be modified to use more sensitive assays.

Journal Article↗
PubMed1999

Induction in transgenic mice of HLA-A2.1-restricted cytotoxic T cells specific for a peptide sequence from a mutated p21ras protein.

Cytotoxic T cells (CTL) recognize short peptides that are derived from the proteolysis of endogenous cellular proteins and presented on the cell surface as a complex with MHC class I molecules. CTL can recognize single amino acid substitutions in proteins, including those involved in malignant transformation. The mutated sequence of an oncogene may be presented on the cell surface as a peptide, and thus represents a potential target antigen for tumour therapy. The p21ras gene is mutated in a wide variety of tumours and since the transforming mutations result in amino acid substitutions at positions 12, 13 and 61 of the protein, a limited number of ras peptides could potentially be used in the treatment of a wide variety of malignancies. A common substitution is Val for Gly at position 12 of p21ras. In this study, we show that the peptide sequence from position 5 to position 14 with Val at position 12-ras p5-14 (Val-12)-has a motif which allows it to bind to HLA-A2.1. HLA-A2.1-restricted ras p5-14 (Val-12)-specific CTL were induced in mice transgenic for both HLA-A2.1 and human beta2-microglobulin after in vivo priming with the peptide. The murine CTL could recognize the ras p5-14 (Val-12) peptide when they were presented on both murine and human target cells bearing HLA-A2.1. No cross-reactivity was observed with the native peptide ras p5-14 (Gly-12), and this peptide was not immunogenic in HLA-A2.1 transgenic mice. This represents an interesting model for the study of an HLA-restricted CD8 cytotoxic T cell response to a defined tumour antigen in vivo.

Amino Acid Sequence↗
PubMed1999

Docosahexaenoic acid is an antihypertensive nutrient that affects aldosterone production in SHR.

The effects of dietary docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, on blood pressure and some pressure-regulating systems were measured in young spontaneously hypertensive rats (SHR). Plasma aldosterone and corticosterone levels, adrenal aldosterone production in vitro, and characteristics of adrenal angiotensin receptors were measured after 6 weeks of diet. Renal cytochrome P450 (CYP) 4A gene expression and arachidonic acid metabolism by renal microsomes were also investigated. Plasma cholesterol, triglycerides, and high-density lipoprotein cholesterol were measured. Diets contained either corn/soybean oil alone (CSO), or oil enriched with DHA. After 6 weeks, rats fed DHA had systolic blood pressures averaging 34 mmHg less than controls (P < 0.001). Plasma aldosterone levels were 33% lower in the DHA-fed animals than in controls (22 +/- 3 vs. 33 +/- 3.7 ng/dl, P < 0.05). Plasma levels of corticosterone were 18% lower in animals fed DHA than in controls, but this difference was not statistically significant. Adrenal glomerulosa cells from DHA-fed rats produced less aldosterone in vitro in response to angiotensin II, ACTH, or potassium. The difference was less marked when aldosterone production was stimulated by supplying exogenous corticosterone, suggesting an effect of DHA on postreceptor steps in signal transduction or the early pathway of aldosteronogenesis. We found no significant differences in angiotensin receptor subtype, number, or affinity. Production of arachidonic epoxides by renal microsomes was 17% lower in DHA-fed animals than in controls (P < 0.05). Renal cortical mRNA levels of CYP4A genes and formation of 19- and 20-hydroxyeicosatetraenoic acid (HETE) did not differ between dietary groups. Plasma total cholesterol and high-density-lipoprotein (HDL) levels were significantly reduced in SHR fed the DHA supplement, but triglyceride levels were not significantly different. The effects of DHA on steroid and eicosanoid metabolism may be part of the mechanism by which this fatty acid prevents some of the hypertension in growing SHR.

Adrenal Glands↗
PubMed1999

Isolation and characterization of thermophilic bacteria capable of degrading dehydroabietic acid.

Using a semi-continuous enrichment method, we isolated two thermophilic bacterial strains, which could completely degrade abietane resin acids, including dehydroabietic acid (DhA). Strain DhA-73, isolated from a laboratory-scale bioreactor treating bleached kraft mill effluent at 55 degrees C, grew on DhA as sole carbon source; while DhA-71, isolated from municipal compost, required dilute tryptic soy broth for growth on DhA. DhA-71 grew on DhA from 30 degrees C to 60 degrees C with maximum growth at 50 degrees C; while, DhA-73 grew on DhA from 37 degrees C to 60 degrees C with maximum growth at 55 degrees C. At 55 degrees C, the doubling times for DhA-71 and DhA-73 were 3.3 and 3.7 h, respectively. DhA-71 and DhA-73 had growth yields of 0.26 and 0.19 g of protein per g of DhA, respectively. During growth on DhA, both strains converted DhA to CO2, biomass, and dissolved organic carbon. Analyses of the 16S-rDNA sequences of these two strains suggest that they belong to two new genera in the Rubrivivax subgroup of the beta subclass of the Proteobacteria. Strains DhA-71 and DhA-73 are the first two bacteria isolated and characterized that are capable of biodegradation of resin acids at high temperatures. This study provided direct evidence for biodegradation of resin acids and feasibility for biotreatment of pulp mill effluent at elevated temperatures.

Abietanes↗
PubMed1999

Altered cardiovascular haemodynamics and baroreceptor-heart rate reflex in adult sheep after prenatal exposure to dexamethasone.

Numerous epidemiological studies, together with mounting evidence from studies in animals, point to a correlation between an adverse intrauterine environment and the early onset of cardiovascular and metabolic diseases later in life. We were the first to show that sheep exposed to dexamethasone (0.28 mg.kg-1.day-1 for only 2 days) at the end of the first month of pregnancy (PTG1), but not those exposed at the end of the second month of pregnancy (PTG2), had a higher basal mean arterial pressure (MAP) 19 months after birth. In the present study we report the MAP, cardiovascular haemodynamics and baroreflex sensitivity in these animals at 40 months of age. MAP in the PTG1 group was significantly higher than in the control group (91+/-1 mmHg and 81+/-1 mmHg respectively; P<0.001) and also when compared with the PTG2 group (82+/-1 mmHg; P<0.001). There was a significant increase in cardiac output in the PTG1 group compared with the control group (108+/-2 and 96+/-4 ml.min-1.kg-1 respectively; P<0.05). The increase in cardiac output in the PTG1 group was due to an increase in stroke volume (1.82+/-0.08 ml.kg-1. beat-1, compared with 1.46+/-0.06 ml.kg-1.beat-1 in the control group; P<0.05), but not in heart rate. In the hypertensive group of animals (PTG1), there was a rightward shift of the baroreflex curve. In group PTG2 (the normotensive group of animals), a lower gain was found before and during propranolol treatment. The decrease in gain of the baroreflex was not associated with changes in heart rate range, suggesting an impairment in the central processing of the baroreceptor signals. Thus sheep fetuses exposed to dexamethasone for only 2 days at the end of the first month of gestation have high blood pressure (dependent upon the increase in cardiac output) and a reset of the baroreflex at 40 months of age. Animals that have received prenatal dexamethasone closer to mid-gestation, although normotensive with normal cardiac output, showed an altered baroreceptor-heart rate response.

Animals↗
PubMed1999

Sweat gland adenoma with predominant myoepithelial differentiated features: case report and immunohistochemical study.

A 56-year-old man presented with a subcutaneous mass adjacent to the sternoclavicular joint region, which had predominant spindle-shaped myoepithelial cells and a small number of tubular or trabecular epithelial cells that resembled eccrine differentiation under a light microscope. Immunohistochemical studies showed positive staining for muscle-specific actin and vimentin in the myoepithelial cells, but staining was negative for S-100 protein and keratin. The tubular and trabecular epithelial cells stained positively for keratin, EMA and CEA. We believe that this rare tumor had the potential for biphasic differentiation and should be differentiated from other biphasic differentiated or mixed tumors in this site. Immunohistochemical staining was useful for diagnosis and differential diagnosis.

Adenoma↗
PubMed1999

[Genetic complementation group analysis of xeroderma pigmentosum patients in China].

OBJECTIVE: To establish skin fibroblast cell strains derived from Chinese xeroderma pigmentosum(XP) patients and to analyze the genetic complementation group and distribution. METHODS: From four XP patients, skin fibroblast cell strains were derived and used for the complementation group analysis by autoradiography and cell-fusion technique. RESULTS: Of the four XP patients from apparently independent families, three were assigned to group C, and one belonged to group E. This is the first report on XP-E patient in China. CONCLUSION: Based on the data from the previous 7 cases and the present 4 cases, the distribution of complementation group in Chinese XP patients known at present is: nine XP-C, one XP-F and one XP-E. Although the number of cases is still limited, XP-C appears to be more frequent in China. This forms a marked contrast to Japanese XP patients, who are dominated by XP-A with infrequent presence of XP-C.

Adolescent↗
PubMed1999

Upper GI bleeding.

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Acute Disease↗
PubMed1999

Upper GI bleeding

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Journal Article↗
PubMed1999

Effects of total parenteral nutrition on rat bile canaliculi: a stereologic analysis.

OBJECTIVE: To quantitate, in a stereologic manner, changes in bile canalicular morphology before and after choleretic infusion of total parenteral nutrition (TPN) and to determine whether TPN produces changes in localized regions within the hepatic lobule. STUDY DESIGN: Livers were obtained from sham-operated on normal adult male rats (control) and from rats that received intravenous TPN solution containing 20% glucose and 3.5% Molipron F. The tissues, obtained by a rigorous sampling procedure, were systematically subjected to stereologic analysis. Measurements were made on electron micrographs at two levels of magnification by point, intersection and profile counts, and then volume, surface area and length were estimated per unit parenchymal volume. RESULTS: The surface area of the canalicular wall per parenchymal volume increased significantly (from 5.33 x 10(-2) to 6.73 x 10(-2) microns 2/micron 3) after TPN treatment, as did the length of microvilli (from 0.241 to 0.267 microns/micron 3). However, the volume of bile canalicular lumina per parenchymal volume (0.306% and 0.320%), total length of bile canaliculi (1.05 x 10(-2) and 1.06 x 10(-2) microns/micron 3) and diameter of microvilli (8.73 x 10(-2) and 8.94 x 10(-2) microns) remained constant. CONCLUSION: These results indicate that changes in canalicular shape and microvillus hypertrophy may cause lowering efficiency of the bile flow rate.

Animals↗
PubMed1999

[Induction and validation of arterial calcium overload in rats].

OBJECTIVE: To induce arterial calcium overload (ACO) in rats and analyze its features. METHODS: Arterial calcium content and intracellular calcium content were determined by atomic absorption spectrometer and electron probe microanalysis, respectively. The morphological changes of endothelial cells and vascular smooth muscle cells were studied with scanning and transmission electron microscopes. DNA contents and its mass distribution were determined by DNA imaging analysis. Arterial collagen and elastin contents were determined biochemically. RESULTS: Seven days after the induction of ACO with selected regimen, massive calcium was found accumulating in the arterial wall, including the cytoplasm and mitochondrion of the medial smooth muscle cells, indicating both extracellular and intracellular calcium overload. Degeneration of aortic endothelial cells was found at the early stage of ACO under scanning and transmission electron microscope. At the late time of ACO, significant proliferation and sclerotic reactions of arteries occurred, including the proliferation of smooth muscle cells, matrix remodeling, and damage of elastic structure. The average DNA content per smooth muscle cell was elevated, and more cells entered the S phase of proliferating cycle since day 7. On the other hand, total collagen content of aorta was increased 7 days after induction of ACO, and rose continuously at day 14 (P < 0.05). Functional studies showed that arterial elasticity was significantly impaired. CONCLUSION: Our method could induce ACO/constantly in rats, and the ACO model shares the similarities with the characterization of human arteriosclerosis on many aspects.

Animals↗
PubMed1999

Expression of leukocyte adhesion molecules CD11b, L-selectin and CD45 during hemodialysis.

OBJECTIVE: To examine the gene and protein expression of CD11b, L-selectin and CD45, and the relationship between their expression and leukocytopenia during a hemodialysis session. METHODS: Ten maintenance hemodialysis patients, 20 uremic non-dialysis patients and 10 healthy volunteers were included in this study. The mRNA expression of CD11b, L-selectin and CD45 in peripheral blood mononuclear cells was detected by RT-PCR, while cell surface expression of these molecules on monocytes was detected by flow cytometry and leukocyte number was counted manually. RESULTS: After the start of dialysis, both mRNA expression and cell surface expression of CD11b increased rapidly, while those of L-selectin and leukocyte number fell. The mRNA expression of CD45 first decreased and the cell surface expression increased, followed by a return to pre-dialysis levels, by the end of dialysis. CONCLUSIONS: Hemodialysis using a cuprophane membrane can induce rapid upregulation of CD11b and down-regulation of L-selectin, which might influence the normal adhesion and anti-inflammatory response of leukocytes. In this process CD45 may play a role in regulating and/or transducing activation signal.

Adult↗
PubMed1999

Subclavian steal syndrome: report of 28 cases.

OBJECTIVE: To study the experience in the treatment of subclavian steal syndrome (SSS) and the relation between SSS and the damage of brain. METHODS: In 28 patients with SSS, 23 were operated on. They complained of vertigo, TIA, and claudication of arms. One patient suffered from severe stem ischemia spasm. All the patients were subjected to subtraction angiography. Fifteen of them showed retrograde flow in the vertebral arteries. Transcranial Doppler revealed retrograde blood flow in 8 patients. Single photon emission tomography showed inadequate blood supply to the brain with affected subclavian arteries in 4 patients. Carotid-subclavian arterial bypass was performed in 16 patients, axilloauxillary bypass in 3, PTA in 1, and aorta-carotid graft bypass in 3. RESULTS: 13 patients (13/23) had their cerebrovascular symptoms relieved. Transcranial Doppler and emission tomography after operation showed nothing abnormal. CONCLUSION: SSS is harmful and the patients should be closely monitored by means of transcranial Doppler and emission tomography.

Adult↗
PubMed1999

[Radiotherapy for early anal cancer: a report of 27 cases].

OBJECTIVE: To evaluate the results of radiotherapy for early stage anal cancer. METHODS: During 1960 through 1993, 27 patients with stage T1-2N0 anal cancer were treated by radiotherapy alone. Seven cases received pelvic irradiation plus local field boost, 20 cases received local field irradiation alone. Kaplan-Meier method was used in survival analysis. RESULTS: The overall 5-year survival rate in this series of patients was 79.1%. Eighteen of the 27 cases had their anal functions preserved. Local recurrence occurred in 7 cases and regional lymph node metastasis in one case. Five of them were salvaged, two by surgery and three by irradiation. CONCLUSION: Radiotherapy alone for early anal cancer is effective. Anal function is preserved in about two-thirds of the patients so treated. Local treatment failure can be salvaged by surgery or radiotherapy.

Adult↗
PubMed1999

[Clinical study on tangshen mixture in treating diabetic nephropathy].

OBJECTIVE: To investigate the effects of Tangshen Mixture (TSM) on the serum glucose, quantity of proteinuria per 24 h, hypercoagulative status and oxidative injury in patients with diabetic nephropathy (DN). METHODS: Ninety-three patients with DN were randomly divided into treated group and control group. 48 patients in the former were treated with insulin and TSM, while the latter was treated with insulin alone. Before and after treatment, the levels of fasting blood glucose (FBG), 2 h after meal blood glucose (PBG), 24 h urinary albumin (24 h-pro), endothelin (ET), alpha-granule membrane glycoprotein-140 (GMP-140), erythrocyte superoxide dismutase (ESOD), lipid peroxidase (LPO) were measured. RESULTS: After two months treatment, compared with the control group the levels of ET and GMP-140, LPO, and 24 h-pro lowered obviously (P < 0.01, P < 0.05), and the level of ESOD increased (P < 0.05) in the treated group, no obvious change was found in control grout after treatment. CONCLUSION: TSM could improve the hypercoagulative status, alleviate the renal free radical disturbances, and reduce the urinary protein loss.

Adult↗