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Biomedical subjects

M Y Wu

Publications and source records attributed to M Y Wu.

At least 19 recordsLinked to original sources
PubMed2003

Secondary sulphonylurea failure: what pathogenesis is responsible?

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.

Adult↗
PubMed2002

Dependence on initial conditions of an adsorption-desorption process.

A one-dimensional irreversible adsorption-desorption process is simulated. The critical parameters as well as the critical exponents are measured. At the critical point, the crossover between the accumulative state and the depleted state is described by a universal characteristic function.

Journal Article↗
PubMed2001

Distribution of Th1 and Th2 cell populations in human peripheral and decidual T cells from normal and anembryonic pregnancies.

OBJECTIVE: To examine whether maternal immune responses during normal pregnancy are Th2 biased and whether there are specific changes when anembryonic pregnancy occurs. DESIGN: Prospective study. SETTING: Department of Obstetrics and Gynecology at a university hospital. PATIENT(S): We studied 32 pregnant women receiving elective abortions of normal pregnancies and 35 women with anembryonic pregnancies between 6 weeks and 10 weeks of gestational age. INTERVENTION(S): Using the multilabeling capability of three-color flow cytometry, it is possible to measure intracellular cytokines and cell surface markers simultaneously to determine which cells are the cytokine-producing cells. MAIN OUTCOME MEASURE(S): We examined the extent and proportion of mononuclear cells expressing specific T-cell surface markers and cytokines, interferon gamma, and interleukin 4 in the peripheral blood and deciduae. Secreted cytokines in the supernatants after 24-hour culture were also compared. RESULT(S): During the unstimulated status, the proportion of IL-4-secreting cells significantly exceeded that of IFN-gamma-secreting cells in the peripheral blood and decidua in normal pregnancies and was significantly decreased when anembryonic pregnancies occurred. Consequently, the Th1/Th2 ratios were increased during anembryonic pregnancies. However, after 24-hour culture, only another Th2-type cytokine, IL-10, was markedly increased and exceeded IFN-gamma secretion in cultures from both the peripheral blood and decidua in normal pregnancies. CONCLUSION(S): The decidual T lymphocytes are Th2 predominant. When anembryonic pregnancy occurs, this Th2 predominance disappears.

Cytokines↗
PubMed2001

Mouse embryo toxicity of IL-6 in peritoneal fluids from women with or without endometriosis.

BACKGROUND: To determine whether there is a factor (or factors) in the peritoneal fluid of endometriosis patients that impairs embryo growth and embryo implantation. METHODS: Growth and development of two-cell mouse embryos which were cultured in media with peritoneal fluid from women with or without endometriosis and interleukin-1-beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels in conditioned media were measured. RESULTS: The blastocyst rate in the non-endometriosis group was 46.4 +/- 31.1%, and that of the endometriosis group was 54.6 +/- 28.7%. Logistic regression analysis using the criteria of blastocyst development in 454 embryos, showed that the peritoneal fluid from endometriosis could promote (p=0.015) but IL-6 could arrest embryo growth to blastocyst (p=0.025). IL-1beta and TNF-alpha levels had no significant effect on blastocyst formation. CONCLUSION: Peritoneal fluid from women with endometriosis was not toxic to mouse embryo development. However, IL-6 in the peritoneal fluid deteriorated the growth and development of mouse embryos.

Adult↗
PubMed2001

Increase in the production of interleukin-10 early after implantation is related to the success of pregnancy.

PROBLEM: To study the correlation of interleukin (IL)-10, IL-11 leukemia inhibitory factor (LIF), placental growth factor (PIGF), and transforming growth factor (TGF)-beta and outcome of human pregnancy. METHOD OF STUDY: We prospectively measured the serum levels of these cytokines in patients undergoing in vitro fertilization (IVF) programs. A total of 60 women (non-pregnant, n = 27; early abortions, n = 12; normal pregnancies, n = 21) were enrolled. RESULTS: There was no difference in the cytokines studied on D0 and D14 among the three groups of women. The increase in PIGF from D0 to D14 after human chorionic gonadotropin (hCG) injection was greater in pregnant women than in non-pregnant women; however, the difference did not reach significance (P = 0.068). The increase in IL-10 production from D14 to D21 was significant in women with successful pregnancies compared to women in the abortion group. CONCLUSIONS: This increase in IL-10 may be important in sustaining a normal pregnancy early after implantation.

Embryo Implantation↗
PubMed2001

The SNRPN promoter is not required for genomic imprinting of the Prader-Willi/Angelman domain in mice.

In mice and humans, the locus encoding the gene for small nuclear ribonucleoprotein N (SNRPN/Snrpn), as well as other loci in the region are subject to genomic imprinting. The SNRPN promoter is embedded in a maternally methylated CpG island, is expressed only from the paternal chromosome and lies within an imprinting center that is required for switching to and/or maintenance of the paternal epigenotype. We show here that a 0.9-kb deletion of exon 1 of mouse Snrpn did not disrupt imprinting or elicit any obvious phenotype, although it did allow the detection of previously unknown upstream exons. In contrast, a larger, overlapping 4.8-kb deletion caused a partial or mosaic imprinting defect and perinatal lethality when paternally inherited.

Angelman Syndrome↗
PubMed2001

Experimental and clinicopathologic study on the relationship between transcription factor Egr-1 and esophageal carcinoma.

AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor. METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry. RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P < 0.01) and the average growth rate of tumor in SCID mice (35.5 +/- 7.6 vs 65.8 +/- 7.6, P < 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 0.01). CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.

Animals↗
PubMed2001

Effectiveness of postoperative adjuvant therapy in improving reproductive outcome of endometriosis-associated infertility.

BACKGROUND AND PURPOSE: Treatment of endometriosis-associated infertility has not yet become standardized. Various protocols including surgical treatment, medical therapy, and a combination of both have been suggested but their use remains controversial. The objective of the present study was to determine whether postoperative adjuvant therapy for endometriosis is effective in improving reproductive outcome. METHODS: Medical records of infertile patients with newly diagnosed endometriosis treated in a university teaching hospital during a 50-month period were reviewed. After exclusion of patients with other major infertility factors, a total of 209 patients were included in the retrospective analysis. These patients were divided into those receiving (n = 78) or not receiving (n = 131) peri- or postoperative adjuvant medical therapy. The adjuvant therapies included danazol (n = 62), gonadotropin releasing hormone analogues (n = 11), progestins (n = 3), oral contraceptives (n = 1), and mixed treatment (n = 1). RESULTS: The pregnancy rate was lower in those receiving adjuvant therapy, although this result was not significant (32.1% vs 45.8%; p = 0.05). When patients using postoperative danazol therapy were considered alone, the pregnancy rate in patients receiving adjuvant therapy was significantly lower than that in patients not receiving it (p = 0.047). When the stage of endometriosis was considered, the pregnancy rate in patients receiving adjuvant therapy was again lower than in those not receiving it in patients with minimal or mild endometriosis (42.9% vs 60%; p = 0.043). However, in patients with moderate or severe endometriosis, the pregnancy rate was not different in the two groups (31% vs 36%; p = 0.56). Postoperative assisted reproductive techniques (ART) including controlled ovarian hyperstimulation/intrauterine insemination (COH/IUI) and in vitro fertilization (IVF) were effective in improving the pregnancy rates for all patients (53.9% with ART vs 33.1% without; p = 0.003) and for patients with advanced endometriosis (47.7% with ART vs 27.2% without; p = 0.016). CONCLUSIONS: Our results suggest that postoperative adjuvant therapy is ineffective in improving reproductive outcome in patients with either early (minimal or mild) or advanced (moderate and severe) endometriosis. This finding suggests that if fertility is the goal of treatment, adjuvant therapy may be unnecessary after surgery. In contrast, our data suggest that empirical ART, including COH/IUI or IVF, may be a better alternative to improve the pregnancy outcome after surgery.

Adult↗
PubMed2001

[A study on pathological changes of closed diffuse brain injury in rats with H.E., esterification-silver stain and albumin immunohistochemical stain].

OBJECTIVE: To observed the pathological changes of closed diffuse brain injury in the rats died immediately and 15 min to 5 days after the injury. METHODS: H.E. staind and esterification-silver stain were applied to investigate the closed diffuse brain injury. RESULTS: In rats died immediately after the concussive injury, a number of shrunken neurons(type I change), distended neurons(type II change) and wave-like nerve fibers were identified in the brain tissue, especially in brain-stem. At 2 h and 8 h after injury, brain edema and axonal swelling appeared clearly in the cortex and white matter, especially in brain-stem. At post-traumatic 8 h and 24 h, the axonal retraction balls began to appear. The amount of neurons undergoing type I and II changes and constraction balls increased along with the survivor time. After 4 days and 5 days, brain edema alleviated, but the retraction balls and axonal swelling still existed. With Esterifica-tion silver stain, the above changes of neurons and nerve fibers were more obvious. With ABC stain, the distribution of albumin(Al) was extended from the perio-vascular area to diffuse distribution. Al positive staining were more obvious in injuried neurons and nerve fibers. CONCLUSION: The distribution of the concussive damage in the brain are coup, contra-coup and centripental.

Albumins↗
PubMed2001

[Recent progress of study on single nucleotide polymorphisms].

Single nucleotide polymorphisms (SNPs) is a new genetic marker system following RFLP and microsatellite polymorphism. It has been shown to have the characteristics of high-density, inheritance stability and facilitation in analysis automation. SNPs can be detected by electrophoresis, endonuclease-cleavage, PCR and sequencing, and can be used extensively in gene mapping, disease-correlativity analysis, population genetics and drug research.

Chromosome Mapping↗
PubMed2001

[A study of genetic polymorphism of the STR locus D2S441 in Chinese Han population in Chengdu].

Using PCR and PAG, followed by silver staining, the tetrameric STR D2S441 locus was studied in 260 unrelated Chinese individuals living in Chengdu. 9 alleles and 26 genotypes were observed. The range of fragment size was 131 bp to 155 bp. The genotype distribution of D2S441 locus in Han population was in accordance with Hardy-Weinberg equilibrium. Family survey confirmed Mendelian inheritance of alleles. The discriminating power (Dp), observed heterozygosity (H), polymorphism information content (PIC) and power of exclusion (PE) were 0.9084, 0.7885, 0.7390 and 0.5778 respectively. The results demonstrated that this locus was highly polymorphic and could be used for forensic identification and paternity testing.

Alleles↗
PubMed2001

[Bone union of distracted region after limb lengthening].

OBJECTIVE: To investigate the factors which affect the bone union of distracted region after limb lengthening, so as improve the curative effect and diminish the incidence of complication. METHODS: To look up the latest literatures dealing with the bone union in limb lengthening, then review the procedure of osteogenesis and the affecting factors. RESULTS: The osteogenesis of distracted region after limb lengthening is a sophisticated procedure. It can be affected by the velocity of lengthening, the period of lengthening, the site and method of osteotomy, the age etiology of patient. CONCLUSION: The bone union of distracted region after limb lengthening can be facilitated by following factors: 1. the velocity of lengthening slower than 1.0 mm/day; 2. moderate delay in distraction; 3. axial shortening of distracted region; 4. micromovement stimulation.

Absorptiometry, Photon↗
PubMed2000

Hormone replacement therapy reverses the decrease in natural killer cytotoxicity but does not reverse the decreases in the T-cell subpopulation or interferon-gamma production in postmenopausal women.

OBJECTIVE: To investigate the immunologic deviations of postmenopausal women before and after hormone replacement therapy (HRT). DESIGN: Prospective study. SETTING: University teaching hospital. PATIENT(S): Seventeen postmenopausal women (study group) and 17 women of reproductive age (control group). INTERVENTION(S): Continuous usage of E(2) valerate 2 mg/d and medroxyprogesterone acetate 5 mg/d in postmenopausal women in the study group. MAIN OUTCOME MEASURE(S): Immunophenotyping with flow cytometry, cytokine production with and without mitogen stimulation of the peripheral mononuclear cells, and a natural killer (NK) cell cytotoxicity test against K562 target cells by the (51)Cr-release assay were performed in the control group and in the study group before, 1 month after, and 6 months after HRT. RESULT(S): NK cytotoxicity, interferon-gamma production, and the T-cell subpopulation were significantly decreased, and the subpopulations of CD3(+)CD25(+) and CD3(+)HLA-DR(+) were increased in the study group before HRT when compared with those in the control group. After HRT was given for 6 months, however, the NK cytotoxicity increased significantly in the postmenopausal women to a value similar to that of the control group. CONCLUSION(S): Women after menopause are prone to impaired immune responses. Nevertheless, some of the impairment can be restored after HRT.

Adult↗
PubMed2000

Increase in the expression of killer cell inhibitory receptors on peritoneal natural killer cells in women with endometriosis.

OBJECTIVE: Malfunction of peritoneal natural killer cells (NK) may result in endometriosis. The present study was designed to determine whether the decrease in NK cytotoxicity occurs at early and advanced stages of endometriosis and is due to the increase in the NK inhibition receptors. DESIGN: A case control study. SETTING: A tertiary-care infertility center . PATIENT(S): A total of 44 women (controls, n = 11; women with early-stage endometriosis, n = 11; and women with advanced-stage endometriosis, n = 22) were included in this study. INTERVENTION(S): Laparoscopic examination. MAIN OUTCOME MEASURE(S): NK cytotoxicity was determined by assay of (51)Cr release against K562 cells, and the expression of killer cell inhibitory receptors (KIR, including NKB1, GL183, and EB6) in NK cells was examined by flow cytometry. RESULT(S): Women with endometriosis showed a decrease in peritoneal NK cytotoxicities against K562 at early and advanced stages of endometriosis. The expression of KIR (NKB1 and EB6) was significantly elevated in the peritoneal NK cells of women with advanced-stage endometriosis compared with controls. KIR (NKB1) was also significantly increased in peritoneal NK cells of women with advanced-stage endometriosis, compared with those of women with early-stage endometriosis. CONCLUSION(S): The results of this study suggest that the decrease in peritoneal NK cytotoxicities against K562 is observed and that this disease may be partially due to the increased expression of KIR on these NK cells.

Ascitic Fluid↗
PubMed2000

Relationships of serum pro-inflammatory cytokines and vascular endothelial growth factor with liver dysfunction in severe ovarian hyperstimulation syndrome.

The aims of this study were to determine if differences in serum pro-inflammatory cytokines, vascular endothelial growth factor (VEGF) and clinical pregnancy rate, could be observed in women with severe ovarian hyperstimulation syndrome (OHSS) in those who did and did not have liver dysfunction. Twenty-nine in-vitro fertilization patients with severe OHSS were included. The patients were divided into the normal liver function tests (LFT) group (n = 14) and the abnormal LFT group (n = 15) according to the LFT on day of admission. Periodic measurements of serum interleukin (IL)-6, IL-8, tumour necrosis factor-alpha (TNF-alpha), VEGF, oestradiol, progesterone concentrations, and LFT were performed during hospitalization. Concentrations of IL-6 in the active phase of OHSS were significantly higher in the abnormal LFT group than in the normal LFT group (19.7 +/- 15.7 versus 8.1 +/- 7.0 pg/ml, respectively). The severity of liver dysfunction was not correlated with concentrations of oestradiol, progesterone, haematocrit, white blood cell counts, or any studied cytokine. The clinical pregnancy rate was significantly lower in the abnormal LFT group (46.7%) than in the normal LFT group (85.7%). These results suggest that IL-6 cytokine system may play a role in the pathogenesis of liver dysfunction in severe OHSS. Abnormal LFT were associated with lower clinical pregnancy rates.

Adult↗
PubMed2000

Cardiac troponin I: a marker for post-burn cardiac injury.

Cardiac troponin I (cTnI) was measured by chemiluminescent immunoassay following burn injury. Thirty patients [total body surface area (TBSA) of burn 15-98%] were included in this study and each had four to six blood samples collected at 2-day intervals between the 5th and 14th days post-burn. All patients were found to have increased cTnI on two or more occasions. The mean cTnI concentration was significantly higher in patients with TBSA of burn > 30% (0.34 microg/L compared with 0.09 microg/L, P<0.001) and in those with obvious burn wound exudation (0.32 microg/L compared with 0.12 microg/L, P<0.01). cTnI concentrations peaked at the time when there was obvious burn wound exudation or spontaneous separation of eschar, then decreased after surgical excision. Two patients with persistently high cTnI concentrations developed tachycardia. We conclude that burned patients have varying degrees of non-ischaemic cardiac injury, manifesting as leakage of cTnI from myocytes into the circulation.

Adolescent↗
PubMed2000

Assessment of nutritional status in continuous ambulatory peritoneal dialysis patients: a comparison of bioelectric impedance and conventional methods.

BACKGROUND: Nutritional status is an important factor in long term continuous ambulatory peritoneal dialysis (CAPD) prognoses. Conventionally, serum albumin is an indicator of nutritional status. More recently, protein catabolic rate and lean body mass have been calculated during peritoneal equilibrium testing to assess nutritional status. These have the advantage of providing an early indication of malnutrition before the serum albumin decreases. Bioelectric impedance analysis (BIA) of nutrition has the advantage of being the simplest procedure among all nutritional assessments. Standard nutritional assessments was compared with the BIA method. METHODS: The protein catabolic rate and lean body mass was measured by the Keshaviah method. At the same time BIA was used to assess lean body mass, fat mass and fixed percentage of fat in 27 long-term CAPD patients, with and without peritoneal fluids. RESULTS: Among the 27 patients, the protein catabolic rate was 0.95+/-0.5 g/kg/day and lean body mass was 37.4+/-0.5 kg measured by the conventional method. Using BIA, the lean body mass was 37.8+/-11.0 kg with peritoneal dialysate, which was strongly correlated with the conventional method (p<0.001). BIA of lean body mass was 37.4+/-9.2 kg without peritoneal dialysate, which was also significantly correlated to the conventional method (p<0.001). CONCLUSIONS: BIA nutritional assessment of lean body mass was comparable to the conventional method of nutritional assessment. The presence or absence of peritoneal dialysate did not influence the BIA method for detection of lean body mass. BIA has the advantage of being a more simple procedure and can be used for the long-term assessment of nutritional status in CAPD patients.

Blood Urea Nitrogen↗