Biomedical subjects

Y H Liu

Publications and source records attributed to Y H Liu.

At least 91 records · Page 5Linked to original sources

PubMed2000

[A study on establishing method in analysing EEG state complexity].

Objective. To establish method in analysing EEG complexity as related to brain function state (Cs) and to examine Cs under conditions of taking rest and doing mental arithmetic, to explore their regular changes. Method. EEG of 10 male subjects aged 26-30 under the conditions of taking rest and doing mental arithmetic were recorded. Cs under the two conditions and their changes related to brain function states were analyzed with a special software for Cs analysis. Result. EEG Cs under mental arithmetic changed significantly. According to these changes, the subjects were divided into two groups: Group A, 8 subjects, their EEG Cs under mental arithmetic were significantly higher than Cs under rest at all electrode sites. The most outstanding areas were temporal region and parieto-occipital region. Group B, 2 subjects, their EEG Cs under mental arithmetic were significantly lower than Cs under rest. The most outstanding areas were prefrontal region and temporal region. Conclusion. The result showed that high correlation existed between mental arithmetic and Cs. This method of analysis was useful in studying brain cognitive activities and assessing mental workload.

Adult↗

PubMed2000

Do the CK18 related proteins change in general in epithelial cancers?

The modulation of cytokeratin 18 during tumor transformation in hepatoma had been previously recognized through a series of biochemical and immunological approaches. Expression of cytokeratin 18 in transitional cell carcinoma comparing with hepatoma was investigated using the hepatoma transformation model. CK18 related molecules were found. In the present study, we design various epithelial cancers with the same model. CK18 related molecules were all evident. Therefore, we suggest that CK18 related proteins would play an important role in tumorigenesis of epithelial cancers.

Carcinoma, Hepatocellular↗

PubMed2000

[A fluctuographic analysing of EEG patients with paroxysmal headache].

OBJECTIVE: To offer reference of the screening procedure for aircrew and astronaut selection. METHOD: The competitive frequency-fluctuation characteristics of the dominant frequency in the band of 7-12 Hz in EEG and power density spectra of alpha band power-fluctuation were analyzed with a newer system of electroencephalofluctuographic technology in 20 patients (male 13, female 7, aged 17-37 years) with paroxysmal headache. RESULT: During episodes of headache in the affected sites the cumulated dominant fluctuation probability of each frequency components was in the order of 7, 8, 9, 10, 11, 12 Hz from high to low; The relative entropy value was 92.25% +/- 3.41%; Two peaks having at least 25% higher value than those of its neighbors were observed at 1.86 mHz and 4.65 mHz in power density spectra of power-fluctuation. During the intervals of episodes the above-mentioned probability character disappeared; The relative entropy value was decreased to 69.08% +/- 4.16% ; A new peak was found at 0.93 mHz in spectra power-fluctuation, with a reduction in peak value power at 4.65 mHz. CONCLUSION: It not only offered a parameter for pathophysiological and functional evaluation of paroxysmal headache, but also provided reference of the screening procedure for aircrew and astronaut selection.

Adolescent↗

PubMed2000

[Nonsyndromic deafness and mitochondrial DNA mutation].

OBJECTIVE: To analysis whether there is any mtDNA 1555A-->G homoplasmic point mutation among familial nonsyndromic deafness. METHOD: Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) were used to screen the mutation 1555A-->G among four nonsyndromic deafness families. RESULT: The same mutations were checked out in 4 of 5 individuals in 1 of 4 families. CONCLUSION: The 1555A-->G change on mtDNA might be one of the multiple genetic defects and pathogenetic of familial nonsyndromic deafness.

Adolescent↗

PubMed2000

[Analysis of 1-(2,6-dichlorophenyl)-2-indolone and related materials by high performance liquid chromatography].

The separation of 1-(2,6-dichlorophenyl)-2-indolone (DCI) and related materials in the synthesis of medical intermediate DCI from 2, 6-dichlorophenol and phenylamine was investigated with high performance liquid chromatography under different chromatographic conditions. The results showed that DCI and related materials were in baseline separation by using CLC-CN(150 mm x 6.0 mm i.d., 7 microns) as column, MeOH-H2O(6:4, V/V) as mobile phase and a flow-rate at 1 mL/min. A rapid, accurate and reproducible HPLC method for determining DCI was developed. Fine and crude DCI samples were detected, results showed that N-(2,6-dichlorodiphenyl)-chloracetyl amide (CBCC) was the main impurity in fine sample, and CBCC and 2,6-dichlorodiphenylamine were the main impurities in the crude one.

Aniline Compounds↗

PubMed2000

[Measuring and analyzing of otoacoustic emission tests of a family with genetic progressive sensorineural hearing loss].

OBJECTIVE: To study the diagnostic significance of otoacoustic emission in patients with genetic progressive sensorineural hearing loss. METHOD: To analyse the cochlear function pure tone audiometry Transient Evoked Otoacoustic Emission (TEOAE) and distortion Products Otoacoustic Emission (DPOAE) were measured in 54 members of a six-generation family with genetic progressive sensorineural hearing loss (108 cases) and 50 normal people. RESULT: The family was autosomal dominant heritage. In the group with pure tone thresholds more than 20 dB HL, the amplitudes of TEOAE descended or disappeared in 84% cases and the amplitudes of DPOAE declined or vanished in 82% cases. In the group with normal pure tone thresholds, the amplitudes of TEOAE descended in 75% cases and the amplitudes at one of the frequencies of DPOAE dropped or disappeared in 64% cases. But the incidence of TEOAE and DPOAE in normal people was 100%. CONCLUSION: OAE had important significance in the diagnosis of genetic hearing loss at early stage.

Adolescent↗

PubMed2000

[Genetic epidemiologic study of mitochondrial DNA 7445A-->G mutation among non-syndromic deafness in Chinese population].

OBJECTIVE: To study the Mitochondrial DNA 7445A-->G mutation in nonsyndromic deafness patients in Chinese population. METHOD: Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) were used to screen the mitochondrial DNA 7445A-->G mutation among 128 nonsyndromic deafness individuals from 32 pedigrees, 135 sporadic nonsyndromic deafness patients and 100 normal subjects. RESULT: The 7445A-->G mutation did not appear in the experiment. CONCLUSION: Incidence of the mitochondrial 7445A-->G mutation was lower than that of mtDNA 1555A-->G mutation in nonsyndromic deafness patients in China.

China↗

PubMed2000

[Separation and determination of monosaccharides with high performance liquid chromatography by using internal standard method].

A new approach by which free plant monosaccharides were separated directly and determined with high performance liquid chromatography by using internal standard method was established and beta-indolylacetic acid was selected as the internal standard substance. The separation time for xylose(Xyl), fructose(Fru), glucose(Glu), sucrose(Suc), maltose(Mal), lactose(Lac) and raffinose(Raf) was within 18 min; and the detection limits were 1.8 micrograms, 2.3 micrograms, 2.7 micrograms, 1.8 micrograms, 3.5 micrograms, 4.1 micrograms and 4.3 micrograms respectively while the linear dynamics varied within the range of 5.0 micrograms/L-750 micrograms/L. In this work, the effects of the concentration of CH3CN and pH values in the mobile phase to the separation of the 7 sugars and beta-indolylacetic acid were studied as well. The method can be used to the determinations of jujube, apple samples. Moreover, the recovery experiment was also conducted. The results showed that the relative standard deviations of 5 determinations to Xyl, Fru, Glu and Suc were 1.66%-3.45%, 1.54%-3.01%, 1.29%-2.91%, 1.09%-2.65% and the recoveries were 97.4%-102.1%, 97.3%-101.8%, 98.7%-102.2%, 97.7%-102.5%, respectively.

Chromatography, High Pressure Liquid↗

PubMed1999

Ectopic Msx2 overexpression inhibits and Msx2 antisense stimulates calvarial osteoblast differentiation.

Msx2 is believed to play a role in regulating bone development, particularly in sutures of cranial bone. In this study we investigated the effects of retroviral-mediated overexpression of Msx2 mRNA, in both sense and antisense orientations, on primary cultured chick calvarial osteoblasts. Unregulated overexpression of sense mRNA produced high levels of Msx2 protein throughout the culture period, preventing the expected fall as the cells differentiate. The continued high expression of Msx2 prevented osteoblastic differentiation and mineralization of the extracellular matrix. In contrast, expression of antisense Msx2 RNA decreased proliferation and accelerated differentiation. In other studies, we showed that the Msx2 promoter was widely expressed during the proliferative phase of mouse calvarial osteoblast cultures but was preferentially downregulated in osteoblastic nodules. These results support a model in which Msx2 prevents differentiation and stimulates proliferation of cells at the extreme ends of the osteogenic fronts of the calvariae, facilitating expansion of the skull and closure of the suture.

Animals↗

PubMed1999

Msx2 gene dosage influences the number of proliferative osteogenic cells in growth centers of the developing murine skull: a possible mechanism for MSX2-mediated craniosynostosis in humans.

Throughout its complex morphogenesis, the vertebrate skull must at once protect the brain and expand to accommodate its growth. A key structural adaptation that allows this dual role is the separation of the bony plates of the skull with sutures, fibrous joints that serve as growth centers and allow the calvarial bones to expand as the brain enlarges. Craniosynostosis, the premature fusion of one or more calvarial bones with consequent abnormalities in skull shape, is a common developmental anomaly that disrupts this process. We found previously that a single amino acid substitution in the homeodomain of the human MSX2 gene is associated with the autosomal dominant disorder craniosynostosis, Boston type. This mutation enhances the affinity of Msx2 for its target sequence, suggesting that the mutation acts by a dominant positive mechanism. Consistent with this prediction, we showed that general overexpression of Msx2 under the control of the broadly expressed CMV promoter causes the calvarial bones to invade the sagittal suture. Here we use tissue-specific overexpression of Msx2 within the calvarial sutures to address the developmental mechanisms of craniosynostosis and skull morphogenesis. We demonstrate that a segment of the Msx2 promoter directs reporter gene expression to subsets of cells within the sutures. In late embryonic and neonatal stages, this promoter is expressed in undifferentiated mesenchymal cells medial to the growing bone. By P4, promoter activity is reduced in the suture, exhibiting a punctate pattern in undifferentiated osteoblastic cells in the outer margin of the osteogenic front. Overexpression of Msx2 under the control of this promoter is sufficient to enhance parietal bone growth into the sagittal suture by P6. This phenotype is preceded by an increase in both the number and the BrdU labeling of osteoblastic cells in the osteogenic fronts of the calvarial bones. These findings suggest that an important early event in MSX2-mediated craniosynostosis in humans is a transient retardation of osteogenic cell differentiation in the suture and a consequent increase in the pool of osteogenic cells.

Animals↗

PubMed1999

The fusion gene at the ABO-secretor locus (FUT2): absence in Chinese populations.

The fusion gene (se(fus)) is a null allele of the secretor type alpha (1, 2) fucosyltransferase gene (FUT2) and was first found in a Japanese population. It has not yet been reported in any other ethnic population. In the present study, we investigated the distribution of the fusion gene of the FUT2 locus in five populations from three ethnic groups in East Asia. The fusion gene was found in two additional Japanese populations with a high frequency (0.0551 in Okinawa and 0.0792 in Akita) and, for the first time outside Japan, in a Korean population, at a very low frequency (0.0063 in Seoul). In contrast, we found no fusion gene in two Chinese populations. These findings showed that the FUT2 fusion gene was ubiquitous in Japanese, but was rare in neighboring populations, suggesting that the FUT2 fusion gene had emerged from within the Japanese. Additionally, a new null allele with a C-to-T substitution at nucleotide 658 was found in one individual native of southern China.

ABO Blood-Group System↗

PubMed1999

Reduction of myocardial infarct size by inhibition of inducible nitric oxide synthase.

The inducible nitric oxide synthase isoform (iNOS) is upregulated by cytokines and endotoxins in many types of cells, including cardiac myocytes. Nitric oxide (NO) induced by cytokines can be cytotoxic, and has been implicated in the pathophysiology of myocardial infarction, cardiomyopathy, and septic shock. To examine the role of iNOS in the ischemic myocardium, we studied: 1) the time course of expression of iNOS mRNA after myocardial infarction (MI) in male Sprague-Dawley rat hearts and expression of iNOS protein in the infarcted region; 2) whether hypoxia in vitro is a potential mediator of the induction of iNOS mRNA; and 3) whether inhibition of iNOS by two different selective inhibitors (aminoguanidine and S-methylisothiourea sulfate) in vivo influences infarct size. Myocardial infarction was induced by ligation of the left anterior descending coronary artery (LAD), and tissue was collected at selected times thereafter from both ligated and sham-operated rats. iNOS mRNA was induced in the infarcted region of the left ventricle for 7 days; iNOS protein was also detected in the infarcted area. We next tested whether hypoxia would induce iNOS in vitro. In cultured neonatal ventricular myocytes, iNOS mRNA was slightly induced by 6 to 24 h of hypoxia; however, iNOS protein was only detected when the cytokine interleukin-1beta was present. To study whether iNOS activity contributed to myocardial damage (eg, infarct size), we administered the first dose of the NOS inhibitors 24 h before LAD occlusion and then a second dose after surgery. Inhibition of iNOS activity with aminoguanidine reduced infarct size by 20% but had no effect on infiltration by neutrophils, whereas the more selective inhibitor S-methylisothiourea sulfate reduced infarct size by 41%. These data suggest that NO derived from the iNOS isoform contributes to some of the myocardial injury following MI, possibly by causing myocardial cell death in areas bordering the ischemic region of the heart.

Animals↗

PubMed1999

Emphysema surgery--loop ligation approach.

OBJECTIVES: To demonstrate the efficacy of using thoracoscopic endoloop ligation of bullae in patients with bullous emphysema. METHODS: From 1992 to 1997, 93 advanced age (mean age, 66 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Thoracoscopic loop ligation of bulla was carried out under general anesthesia with double lumen endotracheal tube and single lung ventilation. RESULTS: Eighty-two patients (88%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 7.5 days (range, 4-19 days). Average hospital stay was 9.5 (range, 5-26) days. There was no post-operative death. A comparison of pre-operative and post-operative functional evaluation was available in 27 patients who showed an average increase in FEV1 (from 0.89 to 1.12 l) and declined in residual volume after operation. Complications include persistent airleak over 10 days in nine patients (9.7%), wound infection in three patients and localized empyema in five patients. There was no recurrent after a mean follow-up of 37 months. CONCLUSION: Thoracoscopic loop ligation of bulla has proven to be a safe, reliable and cost effective means of technique for bullous emphysema.

Aged↗

PubMed1999

Attenuation of house dust mite Dermatophagoides farinae-induced airway allergic responses in mice by dehydroepiandrosterone is correlated with down-regulation of TH2 response.

BACKGROUND: Dehydroepiandrosterone (DHEA), an abundant androgen in circulation, has important immunomodulating effects on T-cell differentiation; however, it is not known whether this hormone influences allergic responses. OBJECTIVE: We have established a murine model of airway inflammation induced by house dust mite Dermatophagoides farinae (Der f). Der f challenge of sensitized mice would elicit a pulmonary eosinophilic inflammation. In the present study, we employed this model system to explore the effect of DHEA on allergic responses. METHODS: Female BALB/c mice were fed with a standard diet incorporated with 1.5% (w/w) of DHEA for 1 week before sensitization and every other day for an additional 2 weeks after sensitization. After intratracheal inoculation of allergen, the Der f-induced airway inflammation, immunoglobulin (Ig)E antibody production, and cytokine expression were compared between control and DHEA-fed mice. RESULTS: In control mice the Der f-induced eosinophilia in bronchoalveolar lavage (BAL) fluids was accompanied by an increase in production of interleukin (IL)-4, IL-5, and interferon IFN-gamma systemically and locally. DHEA supplementation did not affect the body weight of mice. However, in mice that were receiving DHEA, the numbers of eosinophils and lymphocytes in BAL fluids significantly decreased at days 2 and 6 after challenge as compared with control mice. Concomitantly, total IgE antibody concentrations as well as IL-4, IL-5, and IFN-gamma levels in BAL fluids or serum also significantly reduced. Immunocytochemical staining of BAL cells revealed that there were fewer IL-4-, IL-5-, IL-10-, but not IFN-gamma-positive stained cells in DHEA-fed mice than in mice who consumed unsupplemented diet. Reverse transcription-polymerase chain reaction analysis demonstrated DHEA decreased the expression of IL-5 and IL-10 transcripts in BAL cells. CONCLUSIONS: Our results showed that administration of DHEA during allergic sensitization could attenuate the subsequent allergic responses elicited by challenge, and that the suppressive effect of DHEA was associated with a down-regulation of TH2 response.

Animals↗

PubMed1999

Cost comparisons between family-based care and nursing home care for dementia.

A prospective study was carried out in Taiwan to measure the family cost of caregiving at home for 289 patients newly diagnosed with dementia (106 with senile-type dementia, 171 with vascular-type dementia). Their families were first interviewed in the outpatient department and then followed for 1 month after the dementia diagnosis was made. Simultaneously, the costs for providing nursing home care to patients with dementia were calculated using accounting data reported from six nursing homes. Comparisons were made between the amount and type of cost encountered by families and by nursing homes to determine whether family-based care was cheaper and more appropriate than nursing home care for dementia patients with different functional levels. The results showed that higher costs were encountered for caregiving at home when the patients had severe dependence. This tendency was more evident for patients with senile dementia than for patients with vascular-type dementia. The cost of labour was an important expense for families caring for patients at home (at least 85% of family costs). Our findings suggest that, when family labour cost is considered, nursing home care is less expensive than family-based care for long-term care, especially for dementia patients with severe or moderate dependence. Nursing home care is also a better choice when patients have great need for multiple health services.

Adult↗

PubMed1999

Epidermal dysplasia and abnormal hair follicles in transgenic mice overexpressing homeobox gene MSX-2.

The homeobox gene Msx-2 is expressed specifically in sites of skin appendage formation. To explore its part in skin morphogenesis, we produced transgenic mice expressing Msx-2 under the control of the cytomegalovirus promoter. The skin of these transgenic mice was flaky, exhibiting desquamation and shorter hairs. Histologic analysis showed thickened epidermis with hyperproliferation, which was restricted to the basal layer. Hyperkeratosis was also evident. A wide zone of suprabasal cells were misaligned and coexpressed keratins 14 and 10. There was reduced expression of integrin beta 1 and DCC in the basal layer. Hair follicles were misaligned with a shrunken matrix region. The dermis showed increased cellularity and empty vacuoles. We suggest that Msx-2 is involved in the growth control of skin and skin appendages.

Abnormalities, Multiple↗

PubMed1999

Dexamethasone reduces nausea and vomiting after laparoscopic cholecystectomy.

We have evaluated the antiemetic effect of i.v. dexamethasone compared with saline in the prevention of nausea and vomiting after laparoscopic cholecystectomy. We studied 90 patients requiring general anaesthesia for laparoscopic cholecystectomy, in a randomized, double-blind, placebo-controlled study. The dexamethasone group (n = 45) received dexamethasone 8 mg i.v. and the saline group received saline 2 ml i.v. at induction of anaesthesia. Anaesthesia was maintained with isoflurane in oxygen. We found that 10% of patients in the dexamethasone group compared with 34% in the saline group reported vomiting (P < 0.05). Of note, the total incidence of nausea and vomiting was 23% in the dexamethasone group and 63% in the saline group (P < 0.001). We conclude that dexamethasone 8 mg significantly decreased the incidence of nausea and vomiting after laparoscopic cholecystectomy.

Adult↗

PubMed1999

Laparoscopically assisted full thickness skin graft for reconstruction in congenital agenesis of vagina and uterine cervix.

In patients with agenesis of the vagina and cervix but with a functional endometrium, the traditional treatment is hysterectomy with construction of a neovagina. We report successful treatment by laparoscopically assisted full thickness skin graft for reconstruction in a patient with congenital agenesis of the vagina and uterine cervix concomitant with haematometra and ovarian endometrioma in a 12 year old girl. Postoperatively, the vaginal skin graft healed well, and menstruation first appeared 4 weeks later. In our opinion, a combined laparoscopic and vaginal procedure with full thickness skin graft is an efficacious alternative in managing such genital defects.

Cervix Uteri↗