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Biomedical subjects

H M Chung

Publications and source records attributed to H M Chung.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cerebral vasculitis in Henoch-Schönlein purpura: a case report with sequential magnetic resonance imaging changes and treated with plasmapheresis alone.

Neurological complications are rare during the course of Henoch-Schönlein purpura (HSP). We report a 7-year-old girl with HSP who presented with seizures, loss of vision and disturbance of consciousness. Magnetic resonance imaging (MRI) showed high signal intensity in the gray and white matter over the left parietal and both occipital lobes, compatible with MRI findings of cerebral vasculitis. The eye fundi revealed multiple branches of retinal artery occlusion. Intravenous pulse methylprednisolone (MTP) followed by oral steroid therapy was initially administered for HSP nephritis. Cerebral vasculitis developed 10 days post-MTP treatment, with progressive worsening of consciousness. Oral steroid was discontinued and plasmapheresis was performed alone. Her level of consciousness dramatically improved after plasmapheresis. The brain MRI and eye fundi findings were consistent with her clinical improvement. To the best of our knowledge, this is the first description of MRI abnormalities and multiple retinal artery branch occlusion of cerebral vasculitis in a patient with HSP that was successfully treated by plasmapheresis alone. In conclusion, we propose that plasmapheresis may be used as a first-line therapy or rescue therapy for cerebral vasculitis in HSP.

Anti-Inflammatory Agents↗
PubMed2000

Pregnancies and deliveries after in vitro maturation culture followed by in vitro fertilization and embryo transfer without stimulation in women with polycystic ovary syndrome.

OBJECTIVE: To improve the efficacy of an IVF-ET program for unstimulated patients with polycystic ovary syndrome (PCOS) with the use of culture for oocyte maturation. DESIGN: Prospective studies with the comparison of different ET procedures from March 1995 through February 1998. SETTING: University-affiliated hospital. PATIENT(S): Ninety-four cycles in 64 consenting patients with PCOS. INTERVENTION(S): Immature oocytes were retrieved from unstimulated patients with PCOS and subsequently cultured and fertilized in vitro. Zygote intrafallopian transfer (ZIFT), uterine ET, or a combined approach of ZIFT + uterine ET was subsequently performed. MAIN OUTCOME MEASURE(S): Laboratory and clinical data. RESULT(S): Among 1, 280 immature oocytes (13.6 +/- 7.5 oocytes per patient) retrieved, 89% (1,139) were morphologically normal, and 62.2% (708/1,139) of the normal oocytes matured in vitro after culture for 48 hours. When intracytoplasmic sperm injection was performed, 68% (481/708) developed to the normal pronuclear stage, and 88.1% of the embryos cocultured with Vero cells (266/302) cleaved. Eighty-five ET cycles were conducted and pregnancy was established in 23 cycles (27.1%), which consisted of 8 after uterine ET and 15 after a combined approach. Seventeen patients delivered 20 normal infants. CONCLUSION(S): The IVF-ET method using no ovarian stimulation followed by in vitro maturation culture can be a feasible assisted reproductive technology for treatment of PCOS with various complications.

Adult↗
PubMed2000

Embryotropic role of hemoglobin and ethylenediaminetetraacetic acid in preimplantation development of ICR mouse 1-cell embryos.

OBJECTIVE: To evaluate embryotropic action of hemoglobin (Hb) and ethylenediaminetetraacetic acid (EDTA) on preimplantation embryo development. DESIGN: In vitro model study using mouse embryos. SETTING: University affiliated hospital, Pochon CHA University. ANIMALS: Four-week-old block strain ICR mice naturally mated after superovulation. INTERVENTION(S): One-cell embryos were cultured in serum-free, modified preimplantation-1 medium, to which 1 microg/ml Hb and/or 0.1 mM EDTA were added. MAIN OUTCOME MEASURE(S): Preimplantation development and blastomere number. RESULT(S): More (P<.05) 1-cell embryos developed to the 4-cell (52% vs. 67%-84%), 8-cell (48% vs. 65%-81%), and blastocyst (40% vs. 61%-79%) stages after the addition of hemoglobin (Hb) and/or EDTA than after no addition. Highest proportion of embryos developed to each stage after the combined addition of Hb+EDTA. EDTA specifically stimulated the development before the 8-cell stage, which was as similar as Hb+EDTA. On the contrary, higher ratio of morula to blastocyst transformation was obtained after the addition of Hb or Hb+EDTA than after no addition (0.76 vs. 0.96-0.98). Significant increases in the cell number of blastocysts (46.5-47.2 vs. 53.2 cells), inner cell mass (ICM) cells (16.7-17.5 vs. 21 cells), and the ratio of ICM cells to trophoblasts (0.3-0.37 to 0.39) were found after the combined addition of Hb+EDTA, compared with no addition or with the addition of EDTA or Hb alone. CONCLUSIONS: Hb and EDTA have stage-specific effects on supporting preimplantation embryo development; Hb promotes both the development before the 8-cell stage and the morula to blastocyst transformation, whereas EDTA mainly promotes the development to the 8-cell stage. The combined exposure of embryos to Hb and EDTA improves not only preimplantation development but also the growth and quality of blastocysts.

Animals↗
PubMed2000

In vitro blastocyst formation of human oocytes obtained from unstimulated and stimulated cycles after vitrification at various maturational stages.

OBJECTIVE: To evaluate the developmental competence and chromosomal normality of oocytes vitrified at various times after maturation culture. DESIGN: In vitro model study. SETTING: A university-affiliated hospital. PATIENT(S): Unstimulated women who underwent cesarean section or oophorectomy and infertile women who underwent a long protocol of GnRH stimulation. INTERVENTION(S): Retrieved oocytes were vitrified at 0 or 48 hours after culture in unstimulated cycles and at 0, 8-15, or 24-28 hours after culture in stimulated cycles. MAIN OUTCOME MEASURE(S): Postthaw morphologic normality, maturation, fertilization, cleavage, blastocyst formation, and chromosome number. RESULT(S): In the 53 oocytes that were obtained from unstimulated cycles, no statistically significant differences were found in rates of morphologic normality (range, 56%-63%) or fertilization (range, 31%-37%) according to the time of vitrification. In the 50 oocytes that were obtained from stimulated cycles, more of those that were vitrified at 24-28 hours were morphologically normal than those that were vitrified at 0 or 8-15 hours. Regardless of these differences, high cleavage rates (83%-100%) were obtained that did not differ significantly among the treatment groups. In both cycles, 20%-43% of cleaved oocytes developed to the blastocyst stage by 6 days after IVF. All the karyotyped blastocysts, three from unstimulated cycles and four from stimulated cycles, had a normal number of chromosomes. CONCLUSION(S): Vitrified and thawed oocytes from unstimulated or stimulated cycles developed to the blastocyst stage, regardless of when vitrification occurred; the number of chromosomes in the blastocysts was normal.

Adult↗
PubMed2000

Risk factors for renal allograft survival in patients receiving cyclosporine immunosuppression.

BACKGROUND AND PURPOSE: Although cyclosporine (CsA) has been widely used in renal transplantation for more than 10 years, no large series of renal transplant patients has been studied in southern Taiwan. The purpose of this retrospective cohort study was to investigate the risk factors for graft survival in renal transplant recipients. METHODS: From August 1987 to January 1998, 101 primary cadaveric renal transplantations were performed. The minimum follow-up period was 1 year. CsA and prednisolone were initially used as immunosuppressive agents in all patients. Use of lower doses of CsA to reduce CsA trough level (50-99 ng/mL) in hepatitis B surface antigen (HBsAg)-positive recipients was attempted at 6 months after transplantation. RESULTS: Graft actuarial survival rates at 1, 5, and 10 years posttransplantation were 89%, 75%, and 57%, respectively. Acute rejection and increased recipient age were found to be significant risk factors (p < 0.05) affecting graft survival, with hazard ratios of 5.20 and 1.74, respectively, by multivariate analysis using a Cox proportional hazards model. Hepatitis B and/or hepatitis C infection had no influence on graft survival. CONCLUSIONS: In this series of cadaveric renal allograft patients, the risk factors affecting allograft survival were acute rejection and recipient age.

Adolescent↗
PubMed1999

Neuregulin induces the expression of mesodermal genes in the ectoderm of Xenopus laevis.

The primary patterning event in early vertebrate development is the formation of mesoderm and subsequent induction of the neural tube by the mesoderm. Some of the transforming growth factor (TGF)-beta family (Activin, Vg1) and the fibroblast growth factor (FGF) family molecules have been implicated for their roles in mesoderm induction. Here we show first the evidence that neuregulin, an epidermal growth factor (EGF)-like growth factor known for its role in neural and muscle differentiation, participates in mesoderm induction. Neuregulin could induce the ectopic expression of mesoderm specific gene Xbra in animal cap explants reared to the midgastrula stage, when animal caps dissected from late blastula were cultured with Neuregulin at a low concentration (10 ng/ml). In situ hybridization study showed that alpha-cardiac actin was expressed in animal caps that were treated with Neuregulin overnight. Skeletal and cardiac muscle specific genes such as MyoD family genes (myoD, MRF4, myf5) and SL1 as well as NCAM, a pan neural marker, were also ectopically expressed by treatment with Neuregulin. However, the expression of NCAM is presumed to be a secondary result of the initial mesoderm induction by Neuregulin. The temporal expression pattern of neuregulin during the early developmental stages was analyzed by RT-PCR in order to determine if neuregulin is expressed at the time of mesoderm induction. It has been found that the neuregulin transcript was already detected from the 16-cell stage (stage 5) and continued to be expressed till the tailbud stage (stage 25), the latest embryonic stage analyzed in this study. Considering that the mesoderm is induced at early blastula before the start of zygotic transcription, maternal neuregulin is expressed at the right time to participate in mesoderm induction. These data strongly suggest that neuregulin plays an important role in mesoderm induction.

Actins↗
PubMed1999

Bladder rupture after inguinal herniotomy.

An 18-month-old male sustained an extensive bladder injury during a routine right inguinal herniotomy. Primary closure of the remaining detrusor was performed. Three months postoperatively he could void spontaneously, but with a small, contracted bladder and bilateral vesicoureteral reflux. He was stable throughout a 6-month follow-up period. Further surgical options will depend upon the bladder capacity and the grade of reflux.

Hernia, Inguinal↗
PubMed1999

Improved human oocyte development after vitrification: a comparison of thawing methods.

OBJECTIVE: To evaluate the developmental competence of vitrified human oocytes thawed using two different methods to establish an effective cryopreservation protocol. DESIGN: In vitro model study. SETTING: University-affiliated hospital. PATIENT(S): Patients who underwent a long protocol of ovarian stimulation with GnRH and gonadotropins. INTERVENTION(S): Vitrified oocytes from the patients were thawed using either a four-step method with 2.5-minute intervals or a four-step method with 5-minute intervals. MAIN OUTCOME MEASURE(S): Morphologic normality, maturation, fertilization, and development of the oocytes to the blastocyst stage. RESULT(S): The two thawing methods did not significantly affect the morphologic normality (84%-100%), maturation (75%-100%), fertilization (38%-71%), polyspermy (more than three pronuclei; 0%-20%), or parthenogenetic activation (only female pronucleus; 0%-8%) of the vitrified oocytes. However, more of the vitrified oocytes developed to the two-cell (71%-100% versus 50%-67%), four-cell (71%-93% versus 0%-50%), eight-cell (46%-71% versus 0%), and blastocyst (23%-36% versus 0%) stages after thawing using the four-step method with 2.5-minute intervals than using the four-step method with 5-minute intervals. CONCLUSION(S): Vitrified human oocytes developed to the blastocyst stage with IVF. A four-step thawing method with 2.5-minute intervals was more effective in supporting preimplantation embryo development than a four-step thawing method with 5-minute intervals.

Adult↗
PubMed1999

Development of in vitro matured bovine oocytes after cryopreservation with different cryoprotectants.

In vitro matured bovine oocytes at the metaphase-II stage were slowly frozen in phosphate buffered saline (PBS) containing 1.0 M glycerol, 1.0 M dimethylsulfoxide (DMSO) or 1.0 M propylene glycol (PROH). When thawed rapidly, more (P<0.05) oocytes were morphologically normal after being frozen with DMSO (86%) or PROH (83%) than with glycerol (62%). When inseminated in vitro with frozen-thawed bull spermatozoa, higher (P<0.05) penetration rates were observed in DMSO (79%) or PROH (76%) than in glycerol (48%). The percentages of oocytes developing to the 2-cell stage at 48 h postinsemination were also significantly (P<0.05) higher in DMSO (51%) and PROH (54%) than in glycerol (33%). However, a significant increase in the proportions of 8-cell embryos (46 vs 21 to 26%; P<0.05) at 72 h postinsemination and morulae (14 vs. 6 to 8%; P<0.05) was derived from oocytes frozen with PROH than with DMSO or glycerol. In conclusion, the type of cryoprotectant used is one of the critical factors affecting developmental competence of bovine oocytes frozen at the metaphase-II stage. For this stage of oocytes, PROH was the most effective, yielding a large number of 8-cell embryos and morulae than either glycerol or DMSO in a slow freezing method combined with a 3-step thawing protocol.

Animals↗
PubMed1999

In vitro maturation and in vitro fertilization of bovine oocytes cultured in a chemically defined, protein-free medium: effects of carbohydrates and amino acids.

This study was conducted to examine the effects of carbohydrates and amino acids on the maturation and fertilization of bovine oocytes. To evaluate the effect of each treatment without any unpredictable interference, oocytes were cultured in a simply defined medium (modified Tyrode's medium; mT) without the addition of hormones and proteins. In Experiment 1, oocyte maturation to the metaphase-II stage was significantly (P<0.0001) enhanced after the addition of glucose (5.6 mM), lactate (10 mM) and/or pyruvate (0.5 mM) to mT (37-74%) than after no addition (0%). In mT supplemented with glucose, the addition of 19 essential and non-essential amino acids (aa; 0, 0.01, 0.1, 1, 5 or 10%) did not further improve in vitro maturation (Experiment 2) or in vitro fertilization (Experiment 3) of oocytes. However, more (P<0.05) pronuclear formation after in vitro-insemination was found in oocytes matured in mT with 1% aa and glucose than in oocytes matured in mT with glucose alone (56% vs. 35%). Penetration of spermatozoa into the ooplasm was initiated at 3 h after insemination and pronuclear formation from 8 h (Experiment 4). When cultured inseminated oocytes were examined up to 192 h post insemination, a significant (P<0.05) increase in the number of 2-cell (18 v. 38%) and 8-cell embryos, (7 v. 20%) and morulae (0 v. 8%) was found after the addition of 1% aa to mT with glucose than after no addition (Experiment 5). A limited number of oocytes matured in mT with aa and glucose developed to the blastocyst stage (6%). These results indicate that exogenous carbohydrates and amino acids are prerequisites for the maturation and fertilization of bovine oocytes in vitro. Glucose alone promotes the nuclear maturation of oocytes, whereas amino acids aid the pronuclear formation of fertilized oocytes.

Amino Acids↗
PubMed1999

Evidence that platelet derived growth factor (PDGF) action is required for mesoderm patterning in early amphibian (Xenopus laevis) embryogenesis.

Mesoderm induction is one of the major events of early vertebrate embryonic patterning. It appears to be controlled by sequential and combinatorial actions of several kinds of peptide growth factors. These include activin, fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta), among others. In the present study, the function of platelet-derived growth factor (PDGF) in early Xenopus laevis embryogenesis was investigated. In the animal-cap assay, PDGF caused pre-ectodermal tissue to develop a mesoderm specific morphology (elongation) and to express the mesoderm marker genes, MyoD family and alpha-cardiac actin. In addition, two other genes were expressed -related serum response factor SL1 (a dorsal mesodermal marker) and myosin light chain (MLC2-heart marker). A role for PDGF in normal (in vivo) mesoderm induction is implicated because injection of PDGF receptor alpha antisense RNA into 2-cell embryos erased the animal cap's mesoderm marker expression. Those injected embryos also exhibited morphological abnormalities including incomplete gastrulation, failure of neural fold closing, and abnormal somitogenesis.

Animals↗
PubMed1998

Microtubule and microfilament organization in maturing human oocytes.

Various stages of immature human oocytes were imaged for microtubule, microfilament and chromatin organization. After germinal vesicle breakdown, a small microtubule aster was observed near the condensed chromatin. The asters appeared to elongate and encompass the condensed chromatin. At metaphase I stage, microtubules were detected in the meiotic spindle. The meiotic spindle in metaphase II was a symmetric, barrel-shaped structure containing anastral broad poles, located peripherally and radially oriented. After germinal vesicle breakdown, treatment with taxol induced numerous cytoplasmic foci of microtubules, mainly in the cortex of the oocyte. Microfilaments were observed as a relatively thick uniform area around the cell cortex and were also found near the germinal vesicle position. After germinal vesicle breakdown, the microfilaments were seen in both the cortex and around the female chromatin. In conclusion, this study suggests that both microtubules and microfilaments are closely associated with the reconstruction and proper positioning of chromatin after germinal vesicle breakdown and during meiotic maturation in human oocytes.

Actin Cytoskeleton↗