Biomedical subjects

H C Liu

Publications and source records attributed to H C Liu.

At least 145 records · Page 8Linked to original sources

PubMed1997

Simultaneous detection of multiple gene expression in mouse and human individual preimplantation embryos.

OBJECTIVE: To detect simultaneously multiple gene expression in mouse and human individual embryos by reverse transcriptase-polymerase chain reaction. DESIGN: Transcripts involved in the insulin-like growth factor (IGF) system were detected in mouse and human preimplantation embryos. SETTING: An academic teaching hospital. MAIN OUTCOME MEASURE(S): Transcripts of the IGF family genes. RESULT(S): In the mouse, genes are expressed differentially and messenger RNA transcripts of maternal origin in nonfertilized ova decline gradually until the initiation of the embryonic genome transcription. Insulin-like growth factor-binding protein-2 (IGFBP)-2, -3, -4, and beta-actin transcripts appear to be initiated at the two- to four-cell stage, whereas IGFBP-1, -5, and -6 transcripts are initiated at later stages. Transcription, once initiated, appears to continue through to the blastocyst stage. In humans, almost all genes of the IGF system were expressed in preimplantation embryos. This is the first report of the assessment of IGF family transcripts in individual embryos, and introduces a novel method for research and clinical diagnosis of preimplantation embryos.

Actins↗

PubMed1997

Midfollicular anticardiolipin and antiphosphatidylserine antibody titers do not correlate with in vitro fertilization outcome.

OBJECTIVE: To determine the prevalence of anticardiolipin and antiphophatidylserine antibodies in an IVF population and to correlate their presence and specific isotype with IVF cycle outcome. DESIGN: Retrospective clinical study using stored midfollicular sera for determination of antibody status. SETTING: University hospital infertility clinic. PATIENT(S): Women who underwent IVF treatment in 1991. INTERVENTION(S): Midfollicular sera were used to assess antibody status during the time of stimulation for IVF. MAIN OUTCOME MEASURE(S): Anticardiolipin and antiphosphatidylserine antibody titers and biochemical or sonographic documentation of IVF cycle outcome. RESULT(S): The overall prevalence of anticardiolipin and antiphosphatidylserine antibodies in IVF patients was 7.0% and 11.2%, respectively. There was no statistically significant difference in the prevalence of these antibodies in the groups of patients with a biochemical pregnancy (0 for anticardiolipin and 2.8% for antiphosphatidylserine), spontaneous miscarriage (11.4% for anticardiolipin and 20% for antiphosphatidylserine), ongoing pregnancy (7.3% for anticardiolipin and 11.6% for antiphosphatidylserine), and patients who failed to conceive (7.2% for anticardiolipin and 10.8% for antiphosphatidylserine). There was no correlation between outcome and the antibody isotype expressed. CONCLUSION(S): Anticardiolipin and antiphosphatidylserine antibodies are poorly predictive of the IVF cycle outcome. Routine testing of IVF patients for the presence of these antibodies is of limited clinical utility.

Abortion, Habitual↗

PubMed1997

Sealing depth of Nd:YAG laser on human dentinal tubules.

Dentin permeability and hypersensitivity are both reduced when the dentinal tubules are occluded. Previous scanning electron microscopic studies showed that Nd:YAG laser could cause melting of dentin and closure of exposed dentinal tubules without dentin surface cracking. Therefore, the aim of the present study was to evaluate the sealing depth of Nd:YAG laser on human dentinal tubules. Thirty-six dentin specimens with exposed dentinal tubule orifices were used in this study. Samples were randomly divided into three groups. Groups A and B were lased by Nd:YAG laser at energy of 30 mJ with 10 pulses/s for a stroke along the dentin surface. Group C was not lased and served as a control. Subsequently, group B was frozen in liquid nitrogen and split by a sharp chisel. Under SEM observation, nonlased specimens showed numerous exposed dentinal tubule orifices, and lased specimens showed melting of dentin and closure of exposed dentinal tubule orifices. The sealing depth of Nd:YAG laser on human dentinal tubules was approximately 4 microns.

Dentin↗

PubMed1997

Effect of hydroxyapatite particle size on myoblasts and fibroblasts.

After surgery, the bone and soft tissues around integrated biomaterials can be adversely affected by implant-related factors acting over a period of years. However, few studies have directly addressed the effects upon the adjacent soft tissue. The present study was designed to test the biological effects of various sized hydroxyapatite (HA) particles on myoblasts and fibroblasts. Both the myoblasts and fibroblasts were mixed in in vitro culture with 0.1% (1 mg ml(-1)) of various sized HA particles (0.5-3.0, 37-63, 177-250, 420-841 microm) for 1 h, 3 h, 1 day, 3 days and 7 days to test their effects on the cell culture. The results show that adding HA particles into a cell culture can decrease the cell count significantly. The transforming growth factor-beta1 (TGF-beta1) concentrations in the culture medium decreased significantly on addition of HA particles. When calculated as a ratio to the cell number, the TGF-beta1 titre increased most significantly in the groups of medium-sized particles. The prostaglandin E2 (PGE2) concentrations in the medium increased significantly. The changes in TGF-beta1 and PGE2 concentrations with the smallest particles were most significant and persisted longer. The inhibitory effects of the HA particles on the cell culture were mediated by the increased synthesis of PGE2. Caution should be exercised before considering the use of an HA product which could easily break down into a fine powder.

Animals↗

PubMed1997

Degradation behaviour of a new bioceramic: Ca2P2O7 with addition of Na4P2O7.10H2O.

A newly produced bioceramic, beta-Ca2P2O7 with addition of Na4P2O7.10H2O (SDCP), has been implanted into the femoral condyle of rabbits. Within 6 weeks after implantation, most of the bioceramic is replaced by new woven bone. On the contrary, block from hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), which are osteoconductible, do not resorb within a short period of time. We believe that the biodegradable behaviour of SDCP may occur in two steps. The first and most important step is the digestion of particles and migration of the particles by phagocytosis. The object of this study is to examine the change in morphologies, chemical compositions and crystal structure of SDCP after soaking in distilled water for a certain period of time. The SDCP ceramic was also co-cultured with leucocytes to observe how the SDCP particles were digested by the leucocytes, so that the mechanism of biodegradable behaviour of SDCP ceramic in vivo might be clarified. Four types of sintered calcium phosphate ceramics were tested in the experiment: SDCP, pure beta-Ca2P2O7 (DCP), HA and beta-TCP. They wee soaked in distilled water at 37 degrees C for up to 30 days. The microstructure and morphology of crystals deposited on the surface were observed using scanning electron microscopy. Sodium, calcium and phosphorus ion contents in the supernatant solution were detected by atomic absorption analysis and ion coupled plasma. In summary, HA and DCP showed no significant evidence of dissolution in distilled water. In static distilled water, calcium ions may be released from beta-TCP into solution during the initial 7 days and then converted into HA by reprecipitation. The results showed that the SDCP was firstly dissolved into small grains or fragments by the solution. The small fragments should be so small as to be digested by the phagocytes in a physiological environment.

Animals↗

PubMed1997

Swallowing difficulty in Parkinson's disease.

Dysphagia is a frequent and potentially serious complication of Parkinson's disease (PD). We examined the oropharyngeal swallowing ability in 19 PD patients (15 men and 4 women, mean age 68.42 years, mean Hoehn and Yahr stage 1.8) using modified barium swallow before and after administering oral levodopa (in combination with benserazide). Twelve (63.2%) patients demonstrated objective evidence of swallowing abnormalities; although only six patients (31.6%) had subjective complaints. Vallecula sinus and pyriform sinus residues were the most frequent abnormalities (47.4% and 42.1%); followed by delayed swallowing reflex (26.3%). Three patients demonstrated silent aspiration. In the 12 patients with abnormal swallowing, six (50%) showed objective improvement after levodopa treatment, while the remaining six showed no change. Of the former group of six, one patient showed improvement in the oral phase, but deterioration in the pharyngeal phase. We concluded that PD patients had a high percentage of objective swallowing abnormalities which could be reduced in half of the patients through the administration of levodopa treatment.

Adult↗

PubMed1997

Depressive disorders among older residents in a Chinese rural community.

BACKGROUND: Two recent surveys of depression among Chinese elderly people sampled different populations, used different case ascertainment methods and resulted in a seven-fold difference in prevalence rates. The present study was conducted to compare prevalence rates obtained with two commonly used methods in the same population, and to examine the risk factors for depression. METHODS: The target population included all residents aged 65 years and over in a rural Chinese community. Participants were interviewed for demographic and medical information, examined by a neurologist and administered Chinese versions of the Geriatric Depression Scale-Short Form (GDS-S), the Cognitive Abilities Screening Instrument (CASI) and an Activities of Daily Living (ADL) form. Individuals who screened positive on the GDS-S were also interviewed by a psychiatrist for diagnosis according to the DSM-III-R criteria. RESULTS: Among the 1313 participants, 26% screened positive on the GDS-S and 13% were diagnosed as having a depressive disorder, including 6.1% with major depression. Individuals with depressive disorders were more likely to have poor ADL scores, lower CASI scores, and chronic physical illnesses. They were also more likely to be female, older, illiterate and without a spouse, but adding these variables did not increase the overall association with the GDS-S score. CONCLUSIONS: Depression was quite common in this Chinese rural geriatric population. The prevalence rate was twice as high when judged by depression symptomatology rather than clinical diagnosis. The critical risk factors were functional impairments, poor cognitive abilities and the presence of chronic physical illnesses.

Activities of Daily Living↗

PubMed1997

Dual suppression with oral contraceptives and gonadotrophin releasing-hormone agonists improves in-vitro fertilization outcome in high responder patients.

Certain patients have a tendency for high response to gonadotrophin therapy which is often not ameliorated with prior gonadotrophin-releasing hormone agonist (GnRHa) suppression. As a result, these patients are frequently cancelled and often experience ovarian hyperstimulation syndrome (OHSS) episodes during in-vitro fertilization (IVF)-embryo transfer cycles. Patients with polycystic ovarian syndrome (PCOS) have been noted to be particularly sensitive to exogenous gonadotrophin therapy. We have developed a protocol which is effective in improving IVF outcome in high responder patients, including those with PCOS. Oral contraceptive pills (OCP) are taken for 25 days followed by s.c. leuprolide acetate, 1 mg/day, which is overlapped with the final 5 days of oral contraceptive administration. Low-dose gonadotrophin stimulation is then initiated on the third day of withdrawal bleeding in the form of either human menopausal gonadotrophins or purified urinary follicle-stimulating hormone at a dosage of 150 IU/day. Over a 5 year period, we reviewed our experience utilizing this dual method of suppression in 99 cycles obtained in 73 high responder patients. There were only 13 cancellations prior to embryo transfer (13.1%). The clinical and ongoing pregnancy rates per initiated cycle were 46.5 and 40.4% respectively. Only eight patients experienced mild-moderate OHSS following treatment. For those patients who had undergone previous IVF-embryo transfer cycles at our centre, significant improvements were noted in oocyte fertilization rates, embryo implantation rates and clinical/ongoing pregnancy rates with this protocol. Hormonal analyses revealed that the chief mechanism may be through an improved luteinizing hormone/follicle-stimulating hormone ratio following dual suppression. An additional feature of this dual method of suppression is significantly lower serum androgen concentrations, particularly dehydroepiandrosterone sulphate.

Adult↗

PubMed1997

Hormonal regulation of expression of messenger RNA encoding insulin-like growth factor binding proteins in human endometrial stromal cells cultured in vitro.

To investigate the presence of messenger RNA (mRNA) encoding insulin-like growth factor binding proteins (IGFBP) in human secretory endometrial stromal cells cultured in vitro, total cellular mRNA and protein extracted from cells treated with various hormones were detected and identified by Northern and Western blotting techniques respectively. Northern blot analysis detected 1.4 and 2.5 kilobase (kb) mRNA transcripts for IGFBP-2 and IGFBP-3 respectively, in both control and progestin-treated human endometrial stromal cells in vitro. However, the 1.5 kb mRNA transcript of IGFBP-1 was detected only in progestin-treated cells but not in the controls. Progestin alone markedly stimulated cellular BP-1 protein and mRNA, but only moderately stimulated cellular IGFBP-2 and IGFBP-3 protein mRNA in a dose-dependent fashion. Adding relaxin at the same time as progestin further enhanced the stimulatory effects of progesterone. Oestradiol had a stimulatory effect on cellular IGFBP-2 mRNA, but had an inhibitory effect on protein and mRNA of IGFBP-3, also in a dose-dependent fashion. In general, for each specific binding protein, the amount of cellular mRNA correlated well with the amount of cellular protein. Therefore, IGFBP protein and mRNA transcript in human secretory endometrial stromal cells appears to be under hormonal influence. These hormones may control the synthesis of IGFBPs at the transcription rather than the translation level.

Cells, Cultured↗

PubMed1997

Non-association between Rfp-Y major histocompatibility complex-like genes and susceptibility to Marek's disease virus-induced tumours in 6(3) x 7(2) F2 intercross chickens.

Marek's disease (MD) is a lymphoproliferative disease caused by a member of the herpesvirus family, and the best understood genetic resistance to MD involves the chicken major histocompatibility complex (MHC) B-complex. Preliminary observations have suggested that MHC-like Rfp-Y genes might also influence the incidence of MD. This study describes the differentiation and definition of unique Rfp-Y genes in inbred lines 6(3) and 7(2), lines that possess identical B-complex genes, but that are resistant or susceptible to MD, respectively. To assess if Rfp-Y genes affect susceptibility to MD, 265 6(3) x 7(2) F2 chickens were challenged with the JM strain of MD virus at 1 week of age and were evaluated for MD lesions at up to 10 weeks of age. Genotyping of the F2 chickens for Rfp-Y haplotypes was performed by restriction fragment length polymorphism analysis of genomic DNA using TaqI and a B-FIV probe. Analysis of variance and interval mapping procedures were used to determine association between the Rfp-Y haplotypes and the phenotypic MD values of the F2 chickens. The cosegregation analysis of 265 F2 chickens indicated that there was no association between Rfp-Y haplotypes and MD susceptibility. Furthermore, the fact that the Rfp-Y haplotypes fit the 1:2:1 segregation ratio and the Rfp-Y allele frequencies did not differ significantly from 0.5 in the full population or in selected subpopulations (of either 40 MD-resistant or 39 MD-susceptible chickens) also indicated that Rfp-Y haplotypes do not significantly influence MD susceptibility. We conclude that Rfp-Y haplotypes do not play a major role in determining the genetic susceptibility to MD in 6(3) x 7(2) F2 White Leghorn chickens.

Animals↗

PubMed1997

Expression of IGFs and their receptors is a potential marker for embryo quality.

PROBLEM: Insulin-like growth factors (IGFs) and insulin have been demonstrated to stimulate oocyte maturation and embryo development. Therefore, the expression of IGFs and their receptors may be an important intrinsic factor for embryo growth and may be a potential marker for embryo quality. METHOD OF STUDY: Thirty donated day 3 embryos were cultured in vitro for an additional 3 days to observe their developmental potential and were semiquantitatively analyzed for the expression of IGF-I, IGF-II, IGF-IR, IGF-IIR, and insulin-R. RESULTS: Our results show that the activity of these gene expressions correlates well with the morphological assessment and that high and more gene expressions were often associated with embryos of high growth potential. CONCLUSION: The IGF system may indeed play an important role in human embryogenesis; IGF gene expressions can be a good indicator of embryonic developmental stage and/or growth potential; finally, the IGF system can serve as a marker for embryo quality.

Base Sequence↗

PubMed1997

The Kinmen Neurological Disorders Survey (KINDS): a study of a Chinese population.

We conducted an epidemiological study of several neurological disorders among the Chinese aged 50 years or older on the islet of Kinmen. All participants were interviewed and examined by neurologists. From the targeted population of 5,061 individuals, 3,915 (77.4%) of them completed the evaluations. Among the 4,087 individuals with whom face-to-face contact was made, the refusal rate was 4.2%. The disorders of interest were dementia, Parkinson's disease, essential tremor, stroke, transient ischemic attacks, and migraine. Among the 3,915 participants, 366 cases were found with 1 or more of the surveyed neurological disorders on the prevalence day, August 1, 1993, yielding a prevalence of 93.5/1,000. The purpose of this study, the general methodology, and some overall findings are presented in this communication in order to provide a common background for detailed findings on each disorder to be reported separately.

Age Factors↗

PubMed1997

Risk factors for Alzheimer's disease: a case-control study.

The extent of current knowledge of risk factors for Alzheimer's disease (AD) is still limited. We conducted a case-control study of 98 AD patients and 98 age- and sex-matched controls. Light smoking had a decreased risk for AD (AD: 2.0%, controls: 21.4%, odds ratio = 0.10, p = 0.003), whereas daily smoking showed a trend to increase the risk for AD (AD: 45.9%, controls: 26.5%, odds ratio = 1.73, p = 0.08). After multivariable analyses factors associated with AD included the presence of apolipoprotein epsilon4 allele, and the duration of well water consumption.

Aged↗

PubMed1997

Poststroke depression among the Chinese elderly in a rural community.

BACKGROUND AND PURPOSE: A door-to-door survey was conducted in two townships in the Kinmen islets to investigate the prevalence and other characteristics related to depressive disorders of stroke survivors in an elderly Chinese population. METHODS: Our target population comprised the registered residents > or = 65 years old (n = 2056) of a total population of 26 105 on August 1, 1993. All participants answered a questionnaire, filled in a Geriatric Depression Scale-short form (GDS-S), and received a neurological examination. Depression was defined as a GDS-S score > or = 5. RESULTS: Twenty-eight of 45 stroke survivors (62.2%) and 491 of 1471 nonstroke subjects (33.4%) were classified as depressed. The frequency of stroke survivors' depressive disorders was significantly higher that of nonstroke subjects (P < .001). Multiple regression analysis indicated that GDS-S scores were most related with the activities of daily living (R2 = .19, P = .004) in the stroke survivors. CONCLUSIONS: Depressed mood was common after stroke, and activities of daily living were an important factor for depression in stroke survivors in the community.

Activities of Daily Living↗

PubMed1997

Prevalence of headaches in a Chinese elderly population in Kinmen: age and gender effect and cross-cultural comparisons.

OBJECTIVE: To investigate the prevalence of headaches in a Chinese elderly population. BACKGROUND: There are few headache surveys in the elderly. Previous studies have shown a low headache prevalence in Chinese. METHODS TARGET POPULATION: eligible registered residents > or = 65 years old (N = 2,003) in two townships of Kinmen Island on August 1, 1993. All participants completed a headache questionnaire and underwent clinical evaluation and examination by a neurologist. Headache diagnoses were made according to the International Headache Society, 1988. RESULTS: 1,533 persons (77%) participated in the study, of whom 584 (38%) had at least one episode of headache in the previous year. One-year prevalence of migraine was 3.0%, and tension-type headache, 35%. The prevalence of migraine, but not tension-type headaches, continued to decline with age in the elderly. Life-time prevalence of "incapacitating headache" was 10%, and that of migraine, 5.2%. Forty-two percent of migraineurs stopped having migraine before this survey. In comparison with "10 years ago" 8% participants felt their current headaches were worse, 25% better, and 67%, no change, with a net improvement of 17%. CONCLUSIONS: We have reported the highest headache prevalence among different Chinese elderly populations, but these were still lower than those reported from Western series. More than half of the elderly life-time migraineurs still had attacks of migraine. Severe headaches, including migraine but not tension-type headaches, declined with age.

Aged↗

PubMed1997

NSAID-induced gastrointestinal damage. Epidemiology, risk and prevention, with an evaluation of the role of misoprostol. An Asia-Pacific perspective and consensus.

The problem of nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal toxicity was reviewed by members of the Asia Pacific League of Associations for Rheumatology (APLAR) in a consensus conference in September 1992. This paper by the participants presents the consensus conclusions incorporating knowledge from recent publications. There had been a high level of concern that much of the toxicity had resulted from extensive and indiscriminate prescribing of NSAIDs. The implementation of evidence-based guidelines was considered likely to be able to effect a substantial reduction in toxicity without significant loss of overall therapeutic benefit. The evidence from which such guidelines could be developed is critically appraised.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1997

[Relationship between syndrome differentiation-typing and expression of platelet-activation molecule CD62P and CD63 on platelets in psoriatic patients].

OBJECTIVE: To understand the relationship between Syndrome Differentiation- Typing and platelet activation in psoriatic patients. METHODS: Expression of platelet-activation molecules CD62P (alpha-granule membrane glycoprotein) and CD63 (lysosomal integral membrane protein) on platelets from 36 psoriatic patients with Syndrome Differentiation-Typing in TCM and 31 health subjects were investigated by using flow cytometry and specific monoclonal antibodies against activated platelet. RESULTS: (1) Increased expression of CD62P and CD63 on platelets from psoriatic patients was observed (P < 0.001); (2) The expression of CD62P and CD63 was in following order: The group of Blood Stasis > Blood Dryness > Blood Heat; (3) Compared with the group of Blood Heat, increased expression of CD62P and CD63 was observed in the group of Blood Dryness (P < 0.001); (4) Compared with the group of Blood Dryness, increased expression of CD62P and CD63 was observed in the group of Blood Stasis (P < 0.001). CONCLUSION: The platelet activation might play an important role in higher blood viscosity, endothelial cell injury, abnormal microcirculation, which was correlated with Blood Stasis, found in psoriasis.

Adolescent↗

PubMed1997

Biocompatibility and osteoconductivity of the pyrost bone substitutes.

The purpose of this study was to re-evaluate the bone regeneration power and the in vitro biocompatibility of the Pyrost bone substitute. Twenty-four adult New Zealand White rabbits were used. Bony defect over both iliac crest and mid-diaphyseal portion of the ulna bone were created. Appropriate sized-block of Pyrost bone substitute were implanted. Four of the animals were killed at each postoperative month to evaluate its bone regeneration power by histologic study. The Pyrost bones were co-cultured with osteoblasts to evaluate its biocompatibility. The results showed that Pyrost bone substitute was quite stable and incorporated well with active bone regeneration. The Pyrost heal better at the iliac crest than at the ulnar defect. The Pyrost was compatible to the osteoblasts. Osteoblasts had successfully seeded and mitotically expanded on the porous surface of the Pyrost bone graft. The result showed that Pyrost bone obviously exerts an intense stimulus on osteo-regeneration in the presence of osteoblasts. We consider Pyrost to be an alternate to the conventional preserved allografts that is occasionally necessary.

Animals↗