Biomedical subjects

H C Liu

Publications and source records attributed to H C Liu.

At least 127 records · Page 7Linked to original sources

PubMed1998

Immunohistochemical analysis of insulin-like growth factor-binding proteins -1, -2, and -3 in implantation sites of the mouse.

PURPOSE: Our purpose was to analyze potential interactions between the embryo and the maternal endometrial interface in vivo by analyzing immunolocalization of insulin-like growth factor-binding proteins (IGFBPs) -1, -2, and -3 in implantation sites of the mouse. METHODS: Six-week-old B6D2F1 female mice underwent superovulation followed by mating and sacrifice at timed intervals. Formalin-fixed paraffin-embedded tissue was used for avidin-biotin immunocytochemical localization of IGFBPs utilizing standard methodology. RESULTS: Immunostaining at 1.5 days post coitum revealed light staining in the epithelial glandular cells and faint staining in decidual stroma for both IGFBP-1 and IGFBP-2. At 7.5-10.5 days post coitum, there was moderate-dense immunostaining in the decidualized stromal cells at the implantation site for all three IGFBPs, whereas light immunostaining was seen in nonimplantation site decidua. CONCLUSIONS: Compartmentalization of immunostaining for IGFBP-1, -2, and -3 within decidualized stroma suggests that these proteins may be regulated by trophoblastic and/or embryonic signals.

3,3'-Diaminobenzidine↗

PubMed1998

Genetic mapping of quantitative trait loci affecting susceptibility to Marek's disease virus induced tumors in F2 intercross chickens.

Marek's disease (MD) is a lymphoproliferative disease caused by the MD virus (MDV), which costs the poultry industry nearly $1 billion annually. To identify quantitative trait loci (QTL) affecting MD susceptibility, the inbred lines 6(3) (MD resistant) and 7(2) (MD susceptible) were mated to create more than 300 F2 chickens. The F2 chickens were challenged with MDV JM strain, moderately virulent) at 1 wk of age and assessed for MD susceptibility. The QTL analysis was divided into three stages. In stage 1, 65 DNA markers selected from the chicken genetic maps were typed on the 40 most MD-susceptible and the 40 most MD-resistant F2 chickens, and 21 markers residing near suggestive QTL were revealed by analysis of variance (ANOVA). In stage 2, the suggestive markers plus available flanking markers were typed on 272 F2 chickens, and three suggestive QTL were identified by ANOVA. In stage 3, using the interval mapping program Map Manager and permutation tests, two significant and two suggestive MD QTL were identified on four chromosomal subregions. Three to five loci collected explained between 11 and 23% of the phenotypic MD variation, or 32-68% of the genetic variance. This study constitutes the first report in the domestic chicken on the mapping of non-major histocompatibility complex QTL affecting MD susceptibility.

Analysis of Variance↗

PubMed1998

Monoclonal antibodies to mammalian heat shock proteins impair mouse embryo development in vitro.

Two-cell mouse embryos (B6D2F1) were cultured in the presence or absence of 100 microg/ml monoclonal antibodies specific for the mammalian 60 kDa (HSP60), 70 kDa (HSP70) and 90 kDa (HSP90) heat shock proteins. Embryo development was evaluated after 3, 5 and 7 days in culture by determining the number of blastocysts, hatched blastocysts and outgrown trophoblasts at the successive time points. At day 3, only 29% (22/75) of the embryos cultured with anti-HSP60 antibody developed to the blastocyst stage (P < 0.0001) as compared to 67% (31/46) of the embryos cultured with anti-HSP70, 72% (43/60) cultured with anti-HSP90, and 79% (49/62) in medium plus mouse IgG1. By day 5, hatched embryos were present in 28% (13/ 46) of the cultures containing anti-HSP70 (P < 0.0001), as opposed to 57% (34/60) containing anti-HSP90 and 73% (45/62) containing IgG1. At day 7, outgrown trophoblasts were observed in 9% (4/46) of cultures containing anti-HSP70 (P < 0.0001), 45% (27/60) containing anti-HSP90 (P < 0.01) and 66% (41/62) cultured in medium plus IgG1. Antibodies to different heat shock proteins exerted a detrimental effect on mouse embryo development at unique development stages. Immune sensitization to heat shock proteins may be a cause of reproductive failure.

Animals↗

PubMed1998

Prevalence and subtypes of dementia in a rural Chinese population.

We conducted a single-stage community-based study of dementia on all registered residents > or =65 years in age in a rural Chinese community. Neurologists conducted semistructured interviews and examined all participants; they also interviewed family members in cases where dementia was suspected. The diagnosis was made by consensus according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed, revised (DSM-III-R). Among the 2,055 contacted individuals, 1,736 (84.5%) participated in the study and 44 ( 13 men and 31 women) were diagnosed as having dementia, including 35 (80%) with probable Alzheimer disease (AD) and 3 (7%) with vascular dementia (VsD). The rates of dementia were 0.5% for ages 65-74 years, 2.9% for ages 75-84 years, and 12.0% for ages 85-101 years. The overall rate was 2.5% for age > or =65 years. After controlling for age, neither a lack of formal education nor being a woman was a risk factor for dementia. At 2-year follow-up, 30 of the 44 demented participants had died, yielding a 2-year survival rate of 32%. The present results corroborated our previous findings of lower prevalence rates of dementia among the Chinese than among Western populations, and both genetic and sociocultural factors may have contributed to the low rates. The lack of neuroradiological imaging studies in the present study may have contributed to the finding of an unusually low rate of VsD.

Aged↗

PubMed1998

Granulocyte macrophage-colony stimulating factor production by autologous endometrial co-culture is associated with outcome for in vitro fertilization patients with a history of multiple implantation failures.

PROBLEM: To determine whether granulocyte macrophage (GM)-colony stimulating factor (CSF) produced by autologous endometrial co-culture was associated with outcome in 53 patients with a history of multiple in vitro fertilization failures. METHOD OF STUDY: The conditioned media from endometrial co-culture cells exposed or non-exposed to human embryos was analyzed for GM-CSF. RESULTS: Exposure or non-exposure to an embryo did not result in an enhancement of GM-CSF production. Insignificant levels of GM-CSF were determined from media alone. ROC analysis revealed that levels of GM-CSF from supernatants of endometrial co-culture exposed to embryos that measured below 130 pg/ml reflected a diminished prognosis (5/17 had a positive pregnancy vs. 21/36 with GM-CSF levels greater than 130 pg/ml; P < 0.05). CONCLUSIONS: The improved outcome associated with GM-CSF values greater than 130 pg/ml may reflect: 1) a direct positive effect of GM-CSF; 2) an embryotrophic factor upregulated by GM-CSF; or, 3) that GM-CSF functions as a marker for the importance of the glandular component in endometrial co-culture systems.

Adult↗

PubMed1998

Granulocyte-macrophage colony-forming-unit assay and liquid suspension culture of bone marrow and peripheral blood in newly diagnosed childhood acute lymphoblastic leukemia.

Granulocyte-macrophage colony-forming-unit (CFU-GM)-assays and/or liquid suspension cultures of bone marrow (BM) and peripheral blood (PB), using human placental conditioned medium as a source of colony-stimulating activity, were performed in 125 children with newly diagnosed acute lymphoblastic leukemia (ALL). Unlike the previous small series which invariably showed poor BM granulocyte-macrophage colony and cluster formations, we found 3 growth patterns. A poor-growth pattern was seen in 101 patients. A low-growth pattern with BM colony and cluster formations in the lower range of the normal limits was observed in 6 patients. All 6 patients had low-risk ALL, and the in vitro growth may reflect the residual normal CFU-GM in BM. Thirdly an over-growth pattern was noted in one patient with refractory ALL. In 49 cases where liquid suspension cultures of BM were performed, 4 had a normal-growth pattern and 42 had apoptotic cells and/or few residual granulocytic/monocytic cells after 7 days of culture. However, in both B cell ALL cases and in 1 refractory T cell ALL case with hyperleukocytosis, repetitive liquid suspension cultures of BM and PB consistently revealed an extensive growth of lymphoblasts. Thus, an over-growth pattern in either the BM CFU-GM assay or liquid suspension culture of BM or PB in children with ALL at diagnosis may indicate a refractory or aggressive disease. A low-growth pattern in the BM CFU-GM assay in children with ALL at diagnosis probably predicts a favorable outcome.

Bone Marrow Cells↗

PubMed1998

Anaesthesia for transmyocardial laser revascularization--initial experience with seven patients.

The introduction of transmyocardial laser revascularization for ischaemic heart disease has brought with it new challenges for anaesthetists. These include acute deterioration of cardiac function, the need for emergency cardiopulmonary bypass and difficulty weaning from haemodynamic support. Recurrent arrhythmias can occur despite amiodarone prophylaxis. We describe our initial experience and the problems we encountered.

Aged↗

PubMed1998

A directed search for quantitative trait loci on chromosomes 4 and 7 in pigs.

Improvements in the porcine genetic map and availability of resource families to study performance traits in pigs have made it possible to re-examine previous findings that linked certain traits to genes or chromosomal regions. Previous studies suggested that chromosomes 4 and 7 may be associated with growth and performance traits. To confirm these previous results, an interval mapping-regression approach was used to determine whether quantitative trait loci (QTL) exist in the Iowa State University reference/resource families. Traits measured were birth weight; body weight at 21 d; weaning weight (weight at 42 d); average daily gain; backfat at the first, 10th, lumbar, and last ribs and average backfat thickness; loin eye area; meat color; marbling; and firmness. The total number of F2 pigs used ranged from 241 to 330 and came from five Chinese x American resource families. Five markers (S0001, SW871, S0175, S0214, and SW445) were genotyped and mapped on chromosome 4, and so were 10 markers (S0064, tumor necrosis factor alpha [TNFalpha], S0102, S0078, S0158, S0066, SW304, SW1083, S0101, and S0212) on chromosome 7. Data were analyzed for each family (breed cross) separately and were also pooled. Experiment-wise thresholds were used to determine significance. Suggestive evidence of QTL on chromosomes 4 and 7 was observed for several traits in pooled and individual family analyses. Suggestive evidence of a QTL with a relatively large effect for average daily gain was detected on chromosome 4 in the pooled analysis. Significant (P < .05) evidence for QTL was seen on chromosome 7 for 10th-rib, last-rib, and average backfat thickness in the pooled data set in a region of the chromosome that was near TNFalpha. These results verify in part that chromosomes 4 and 7 contain QTL for growth and carcass traits.

Animals↗

PubMed1998

Stress distribution in the mandible with unilateral condylar fracture.

OBJECTIVE: The purpose of this study was to investigate the influence of unilateral condylar neck fracture upon the stress distribution in the mandible and the temporomandibular joint (TMJ) to realize primarily the biomechanical mechanism of the temporomandibular joint disorders (TMD) caused by TMJ injury. METHODS: The character of stress distribution in the mandible of a normal human and a patient with TMD induced by unilateral condylar neck fracture followed by malpositioned healing was analyzed quantitatively and compared during centric occlusion by combining spiral computed tomography scanning technology with the three-dimensional finite element method. RESULTS: The patient with unilateral condylar neck fracture followed by malpositioned healing had unbalanced stress distribution in the mandible, such as differing nature and value of stress. The stress in the fractured side was higher than in the nonfractured side, in which the condyle was more evident. The maximum principal stress and minimum principal stress of each region in the fractured mandible were much higher than those in a normal mandible. Stress quality also differed. CONCLUSIONS: The abnormal stress changes after unilateral condylar neck fracture with malpositioned healing may be related to the effect of condylar shape change on masticatory muscle function and occlusion. TMJ injury not only damaged the condylar structure, but also compromised its biomechanic environment. It is preliminarily thought that unbalanced stress distribution, evidently increased stress, and varied stress character are biomechanic mechanisms of TMD. Condylar dislocated fracture should be treated promptly and properly to maintain the proper prognostic stress distribution.

Adult↗

PubMed1998

Ovarian estradiol production in vivo. Inhibitory effect of leuprolide acetate.

OBJECTIVE: To determine the impact of reducing the dose of gonadotropin-releasing hormone agonist (GnRH-a) for controlled ovarian stimulation in in vitro fertilization (IVF) on subsequent response to stimulation and cycle outcome. STUDY DESIGN: An IVF database was searched to identify patients who underwent at least two cycles of ovarian stimulation at a university-based medical center, and a retrospective chart review was performed. Fifty-one patients whose IVF stimulation protocols during the two cycles were identical except for the leuprolide dosage utilized for luteal pituitary suppression were included in the study. Two leuprolide dosages were utilized for suppression: a low dose, 0.5 mg daily, and a high dose, 1 mg daily. The leuprolide dose was uniformly halved upon initiation of gonadotropin stimulation; the gonadotropin dose and preparation were identical in the two protocols. Day 3 follicle-stimulating hormone levels, duration of stimulation, amount of gonadotropins required, midcycle and peak estradiol levels, oocyte yield and implantation rates were compared. RESULTS: Lowering the dose of GnRH-a while maintaining the same stimulation protocol resulted in a faster estradiol rise and higher mean peak estradiol level. The higher estradiol levels were obtained with a lower total gonadotropin dose. The oocyte yield was not affected by the stimulation protocol utilized. CONCLUSION: Lowering the dosage of leuprolide allows higher estradiol levels in those patients. This suggests an inhibitory in vivo effect of leuprolide acetate on ovarian steroidogenesis.

Adult↗

PubMed1998

Assessment of protein conformation in human benign and malignant astrocytomas by reflectance Fourier transform infrared microspectroscopy.

The secondary structure and composition of protein in the tissues of benign and malignant astrocytomas were determined by reflectance Fourier-transform infrared (FT-IR) microspectroscopy. The peak maximum of IR spectra of the tissues from recurrent malignant astrocytoma markedly appeared at higher frequency (1655 or 1663 cm(-1)), which was significantly different from that of the tissues from benign astrocytoma at 1651 cm(-1) and tissues from malignant astrocytoma at 1652 cm(-1). Malignant astrocytoma indicated slightly different compositions in the protein secondary structure from benign astrocytoma. However, a significant increase in beta-turn structure but a marked decrease in beta-sheet and random coil structures were observed in the protein secondary structure of the recurrent malignant astrocytoma. The phenomenon was more pronounced in recurrent malignant astrocytoma pretreated with radiation and chemotherapy. The rapid cell proliferation and cell differentiation of malignant astrocytoma with or without recurrence might be the possible explanations for the different compositions of protein conformational structures.

Adult↗

PubMed1998

Surgery for achalasia: long-term results in operated achalasic patients.

Achalasia is a functional disorder of the alimentary tract due to decreased or absent peristalsis of the esophageal body and obstructive outlet of the esophagus. Surgical treatment, eg. esophagomyotomy of the lower esophageal sphincter (LES), was one choice for resolving the problem and its effect was affirmative from reviews of many internationally authorized articles. However, few reports have ever questioned the long-term effects of it. From January 1968 to May 1996, 159 esophageal achalasic patients, 90 males and 69 females, were admitted due to dysphagia or food regurgitation. One hundred and forty-five patients had received 158 operations related to this benign motor disorder. The majority of patients received either modified Heller esophagomyotomy (M) or M plus modified Belsy Mark IV antireflux procedure (M+W) for primary treatment of their esophageal disorder, while conditional selection with addition of esophageal resection as advanced procedures for failure of primary surgery. We retrospectively studied these patients, collected their preoperative and postoperative clinical results, analyzed the causes of recurrent symptoms, compared the long-term results in different surgical procedures and searched for the pathogenesis of their failure. The results disclosed that the overall success rate for both methods was 73.1% with 85.7% for patients receiving M+W (56) and 64.9% of M (77) only. Through long-term follow-up, we had an improvement rate of 97.4% at an early stage and 53.3% for M at a late stage and 98.4% and 55.6% for M+W, respectively. The postoperative natural course of achalasic patients could be seen and progressive deterioration of the operated patients with time was noted. Several factors might contribute to the causes of unsuccessful surgery. We summarized them as incomplete myotomy, fused or healed myotomy, gastroesophageal reflux (GER), mucosal hernia and co-combined antireflux procedure by hypercalibrated or floppy wrapping. Esophagomyotomy or myotomy plus antireflux procedure for the esophagus could be concluded to rather effective in the long-term but palliative treatments for achalasia chronic deterioration of the results could be found for both of them. Defective myotomy and GER may be the major causes for their failure. The choice of types of surgery between M and M+W was not the cause of the unsuccessful results whereas the operative strategy and procedures would have a certain significance on the long-term effect.

Adolescent↗

PubMed1997

The effects of calcium phosphate particles on the growth of osteoblasts.

With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes for several decades. The focus of this work is to elucidate the biocompatibility of the particulates of various calcium phosphate cytotoxicities. Four different kinds of calcium phosphate powders, including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP), and sintered beta-dicalcium pyrophosphate (SDCP), were tested by osteoblast cell culture. The results were analyzed by cell count, concentration of transforming growth factor-beta 1 (TGF-beta 1), alkaline phosphatase (ALP), and prostaglandin E2 (PGE2) in culture media. The changes were most significant when osteoblasts were cultured with beta-TCP and HA bioceramics. The changes in cell population of the beta-TCP and HA were quite low in the first 3 days, then increased gradually toward the seventh day. The changes in TGF-beta 1 concentration in culture medium inversely related to the changes in cell population. The ALP titer in the culture media of the beta-TCP and HA were quite high in the first 3 days, then decreased rapidly between the third and seventh days. The concentrations of PGE2 in the culture media tested were quite high on the first day, decreased rapidly to the third day, and then gradually until the seventh day. The changes in the beta-DCP and SDCP were quite similar to those of HA and beta-TCP but much less significant. We conclude that HA and beta-TCP have an inhibitory effect on the growth of osteoblasts. The inhibitins effects of the HA and beta-TCP powders on the osteoblast cell cultures possibly are mediated by the increased synthesis of PGE2.

Alkaline Phosphatase↗

PubMed1997

Cloning and characterization of a cotton lipid transfer protein gene specifically expressed in fiber cells.

A cotton genomic library was screened using a fiber-specific cDNA (GH3) encoding a lipid transfer protein (LTP). One genomic clone (1.7 kb DNA insert) containing the Ltp gene (Ltp6) was sequenced and characterized. The Ltp6 contains an open reading frame of 360 bp, which is interrupted by a single intron (136 bp) located in the region corresponding to the C-terminal of the protein. The derived amino-acid sequence of LTP6 is 64% homologous to that of GH3. Like the GH3 gene, the Ltp6 is specifically expressed in fiber cells in a temporal manner. However, its expression level is lower than that of GH3.

Amino Acid Sequence↗

PubMed1997

In vitro cell behavior of osteoblasts on Pyrost bone substitute.

BACKGROUND: Pyrost bone substitute has been shown to be a promising orthopedic biomaterial. However, little is known about mechanisms that are responsible for the genesis and development of the bond between bone and the Pyrost bone substitute. The purpose of this study is to elucidate the in vitro cell behavior of osteoblasts on Pyrost bone substitute. METHODS: By using primary culture of rat osteoblasts, the changes in cell morphology during adhesion and flattening onto the surface of Pyrost bone substitute were studied in vitro. At 1 hour, at 3 hours, and at days 1, 3, and 7 after layering, the cell behavior was observed with scanning electron microscope. RESULTS: The processes of trypsinized osteoblast adhesion and spreading on Pyrost bone substitute consisted of 1) contact of rounded osteoblasts with the Pyrost substrate; 2) attachment of osteoblasts at point of contact; 3) centrifugal growth of filopodia; 4) flattening and spreading of the osteoblasts on the Pyrost substrate; 5) division and growth of osteoblasts; and 6) suspension of the osteoblasts across the pores by their processes. CONCLUSIONS: These results demonstrated that Pyrost can form a physico-chemical bond with osteoblasts. The Pyrost bone substitute not only supports osteoblasts attachment but also allows proliferation of the osteoblasts.

Animals↗

PubMed1997

Effects of calcium phosphate bioceramics on skeletal muscle cells.

With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes. The effects of implants on bony tissue have been investigated. The effects upon adjacent skeletal muscles have not been determined. The focus of this work is to elucidate the biological effects of various calcium phosphate bioceramics on skeletal muscles. Four different kinds of powder of calcium phosphate biomaterials including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP) and sintered beta-dicalcium pyrophosphate (SDCP), were tested by myoblast cell cultures. The results were analyzed by cell count, cell morphology and concentration of transforming growth factor beta 1 (TGF-beta 1) in culture medium. The cell population and TGF-beta 1 concentration of the control sample increased persistently as the time of culture increased. The changes in cell population and TGF-beta 1 concentration in culture medium of the beta-TCP and HA were quite low in the first 3 days of culture, then increased gradually toward the seventh day. The changes in cell population and TGF-beta 1 concentration in culture medium of the silica, beta-DCP, and SDCP were quite similar. They were lower during the first day of culture but increased and reached that of the control medium after 7 days' culture. Most cells on B-TCP and HA diminished in size with radially spread, long pseudopods. We conclude that HA and beta-TCP are thought to have an inhibitory effect on growth of the myoblasts. The HA and beta-TCP may interfere with the repair and regeneration of injured skeletal muscle after orthopedic surgery.

Animals↗

PubMed1997

The correlation of depression with functional activity in Parkinson's disease.

We evaluated 109 Chinese patients with Parkinson's disease (PD) in three ways: using a standardized psychiatric interview for depression and anxiety, using standardized neurological evaluation for motor disability, and using cognitive assessment for cognitive impairment. Six of the 109 patients who had dementia and another two afflicted with organic delusional disorder were excluded from further analysis. The remaining 101 PD patients were divided into the following three groups according to the DSM-III-R criteria: major depressive disorder (n = 18), other depressive disorders (n = 25) including dysthymic disorder and depressive disorder not otherwise specified, and no depression (n = 58). The frequency of major depressive disorder of the 109 PD patients was 16.5%, and the frequency of major and other depressive disorders, taken together, was 42.2%. Using the percentage points measured on the Schwab & England Activities of Daily Living Scale as the dependent variable to fit a multivariate regression model, we found the lower score significantly correlated with the diagnosis of depressive disorder and higher score of the Hamilton Depression Rating Scale, in addition to motor disability and disease severity of PD. Given the high frequency of depression and the significant correlation between depression and performance in daily functional activites, we believe that an evaluation of PD patients for coexisting depression is necessary for a better therapeutic outcome.

Aged↗

PubMed1997

Withholding gonadotropin administration is an effective alternative for the prevention of ovarian hyperstimulation syndrome.

OBJECTIVE: To evaluate the outcomes of IVF and the incidence of ovarian hyperstimulation syndrome (OHSS) after discontinuing gonadotropin therapy in patients at risk of developing OHSS by delaying hCG administration until a drop in serum E2 levels was observed. DESIGN: Retrospective study. SETTING: IVF program at a university center. INTERVENTIONS: Gonadotropin administration was withheld in 22 patients (group 1) when their serum E2 level was > or = 3,000 pg/mL (conversion factor to SI unit, 3.671). Patients continued GnRH analogue injections daily, and hCG was administered when serum E2 levels dropped to < or = 3,000 pg/mL. Outcomes were compared with 26 patients (group 2) in whom embryo transfer was canceled and all embryos cryopreserved for transfer during a subsequent unstimulated cycle. MAIN OUTCOME MEASURES: Outcomes of IVF and incidence of OHSS were compared in both groups of patients. In group 1, follicular and hormonal parameters before and after the coasting interval were compared in pregnant versus nonpregnant patients. In addition, serum hormonal profiles were evaluated daily during the coasting period to determine the effects of gonadotropin withdrawal. RESULTS: Although the mean number of oocytes retrieved was significantly higher in group 2, fertilization rates, miscarriage rates, delivery rates/stimulation cycle, and the incidence of OHSS did not differ significantly between the two groups. CONCLUSION: Withholding gonadotropin administration is an effective alternative to prevent the development of severe OHSS in a high-risk population. Although the risk of cancellation cannot be completely eliminated, this strategy can provide a high pregnancy rate without the need to repeat multiple frozen-thawed cycles.

Adult↗