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Biomedical subjects

H C Liu

Publications and source records attributed to H C Liu.

At least 199 records · Page 11Linked to original sources
PubMed1994

Plasma reduced haloperidol/haloperidol ratios in schizophrenic patients treated with high dosages of haloperidol.

Plasma haloperidol (HL) and reduced haloperidol (RH) levels were measured in 60 schizophrenic patients treated with high to very high HL doses of 40-200 mg/day. Plasma samples were obtained at steady-state conditions and 10-12 h after the evening dose and prior to the morning dose. RH/HL ratios were shown to be dose-dependent. In the lowest dose group of 40-45 mg/day, 77% of the patients had RH/HL ratios < 1.0. At the higher dose of 60-80 mg/day, these results were reversed as 79% of the patients had RH/HL ratios > 1.0. All patients with HL doses greater than 100 mg/day had RH/HL ratios > 1.0. All patients safely tolerated the high haloperidol dosages and only five patients had extrapyramidal side effects that were unresponsive to trihexyphenidyl. Therapeutic improvement was not observed in each patient. Based upon the dose-dependent increase in the RH/HL ratios in schizophrenic patients, the possible mechanism of a 'therapeutic' window for HL is discussed.

Adult↗
PubMed1994

Autoantibody profiles and immunoglobulin levels as predictors of in vitro fertilization success.

OBJECTIVE: Our aim was to determine the predictive value of autoantibody and immunoglobulin determinations as indicators of the success of in vitro fertilization. STUDY DESIGN: This was a blinded study in which laboratory evaluations were performed on coded samples obtained from another institution. Codes were broken and data were analyzed after results of all laboratory tests had been reported out. One hundred five infertility patients who had undergone in vitro fertilization were randomly chosen. Among those, 46 were considered low responders (six or fewer oocytes were retrieved) and 59 as high responders (13 to 30 oocytes were retrieved). Total immunoglobulin G, M, and A levels and 15 autoantibody levels (6 antiphospholipids, 5 antihistones, and 4 antipolynucleotides) were determined separately for immunoglobulin G, immunoglobulin M, and immunoglobulin A isotypes. RESULTS: High and low responders demonstrated an unusual incidence of autoantibody (25% and 30%, respectively) and immunoglobulin (46% and 48%, respectively) abnormalities. They did not differ from each other, however, in either immunoglobulin or autoantibody parameters. Autoantibody and immunoglobulin abnormalities alone or in combination did not predict pregnancy success (24% vs 16%), incidence of chemical pregnancies (15% vs 24%), or clinical pregnancy loss (9% vs 11%) when such women were compared with those without either abnormality. However, the occurrence of hypergammaglobulinemias, in contrast to hypogammaglobulinemias, was associated with a significant decrease in the clinical pregnancy rate (6% vs 24%, p = 0.05). CONCLUSIONS: Neither autoantibody abnormalities nor total immunoglobulin abnormalities allow differentiation between high and low responders in in vitro fertilization cycles. The presence of autoantibody and total immunoglobulin abnormalities also does not predict low clinical pregnancy rates. Within a group of women with immunoglobulin abnormalities, those with hypergammaglobulinemias appear, however, at significant risk for low pregnancy rates with in vitro fertilization. This observation suggests that high total immunoglobulin levels may serve as a marker for an as yet to be determined immunologic factor that adversely affects the chance of conception. The evaluation of total immunoglobulin levels may be indicated as part of a routine infertility workup.

Adult↗
PubMed1994

Rescue of human embryos by micromanipulation.

This chapter evaluates clinical micromanipulation techniques aimed at rescuing abnormally developing zygotes and cleaved embryos. First, the possibility of reversing dispermic zygotes to a normal biparental diploid state was evaluated by extracting the distal pronucleus (that furthest from the polar body). The ratio of X:Y was determined in both groups of embryos by assessing a minimum of two blastomeres using duplex PCR or multiple colour FISH. The ratio of embryos containing only an X chromosome and those with X as well as Y chromosomes in the intact dispermic zygotes was 1.0:2.6, which is similar to the theoretical ratio of 1:3. This ratio was 1.0:1.5 in dispermic zygotes from which the distal pronuclei were removed. Although the ratio of X:Y was altered following removal of distal pronuclei, suggesting frequent targeting of male pronuclei, accidental removal of the female pronucleus could not be excluded. In a second set of mouse experiments, it was shown that the hatching process of embryos that develop with excessive amounts of degenerate material is adversely affected. It was shown that removal of such extracellular material by micromanipulation potentially reverted the hatching process. It was also indicated that immediate removal of the degenerate tissue was more beneficial than that following prolonged co-culture. Assisted hatching is probably the most frequently applied clinical embryo micromanipulation procedure. The outcome of assisted hatching is dependent largely on the mode by which the zona pellucida is breached, the size of the artificial gap and the thickness of the zona pellucida. Embryos with zonae thicker than 17 microns rarely implant. Zona drilling could be detrimental in embryos with thin zonae (< 12 microns). Superficial zona thinning has not enhanced implantation. These observations led to a routine procedure called selective assisted hatching, which involves measuring the zonae before zona drilling and replacement on day 3 of development. This appears to be most successful in older women and those with elevated basal FSH levels. Selective assisted hatching is routinely applied in consenting patients whose embryos have thick zonae, slow development or excessive fragmentation (> 20%). Zona drilling of all embryos, regardless of zona thickness, is being performed in patients aged over 40 years and in those with repeated failures or elevated basal FSH levels. Results in the first group of more than 900 patients indicate that nearly one-quarter of human embryos have the ability to implant.

Animals↗
PubMed1994

Assessing cognitive abilities and dementia in a predominantly illiterate population of older individuals in Kinmen.

A community survey of dementia was conducted on a Chinese islet. A total of 221 men and 234 women in the age range of 50-92 were assessed. The Cognitive Abilities Screening Instrument (CASI), a 100-point cognitive test designed for cross-cultural studies and adapted in Chinese for individuals with little or no formal education, was administered twice by trained field workers with a retest interval of 3 to 4 weeks. In addition, all participants were assessed by physicians who did not know the CASI scores. The physicians' assessment included a complete neurological examination, plus semi-structured tests and interviews covering cognitive abilities, daily activities, depression, cerebrovascular disease, and Parkinson's disease. Dementia was diagnosed by consensus among the physicians according to the DSM-III-R criteria. Among the 455 participants, 16 cases of dementia were identified, including 13 with probable Alzheimer's disease and 1 each with vascular dementia, Parkinson's disease, and alcoholism. The rates of dementia were 0, 3.9 and 11.5% for the age groups of 50-69, 70-79 and 80-92; and 4.4, 2.0 and 0% for the education groups of 0-1, 2-6 and 7-15 years of schooling. No sex difference was found after controlling for education. The Chinese version of the CASI had an intraclass retest reliability of 0.90. Using a cut-off score of < or = 50 for dementia, the sensitivity was 0.88 and the specificity was 0.94. The preliminary study suggests that the CASI can be used in Chinese populations with generally low education levels and that Alzheimer's disease was the most common type of dementia in this population.

Aged↗
PubMed1994

Cardiovascular autonomic functions in Alzheimer's disease.

We investigated cardiovascular autonomic functions in 23 patients with Alzheimer's disease (AD) and 23 age-matched control subjects. The vagal parasympathetic function was assessed with R-R interval variation (RRIV), and sympathetic function with sympathetic skin response (SSR) and orthostatic cardiovascular reflexes. Compared with controls, the AD patients had significantly depressed RRIV during rest (6.4 +/- 1.3% vs. 7.5 +/- 1.6%, p < 0.02) and deep breathing (12.6 +/- 4.6% vs. 17.0 +/- 5.1%, p < 0.006), but all AD patients had normal SSR. After standing for 3 minutes from supine, the changes of blood pressure and heart rate from baseline in AD patients did not differ from those in controls. The AD patients had a lower systolic blood pressure than controls in both supine (130.7 +/- 17.4 vs. 145.4 +/- 20.7 mmHg, p < 0.02) and standing (129.2 +/- 20.1 vs. 146.6 +/- 21.1 mmHg, p < 0.008) positions, especially in those patients with more severe dementia. We conclude that AD patients have mildly impaired autonomic functions, mainly in vagal parasympathetic functions. The pathogenesis and clinical significance of low blood pressure in AD needs further study.

Aged↗
PubMed1994

Effectiveness of shunting in patients with normal pressure hydrocephalus predicted by temporary, controlled-resistance, continuous lumbar drainage: a pilot study.

From 1984 to 1992 15 consecutive cases of normal pressure hydrocephalus were included in this pilot study. A series of tests included CT of the brain, grading of the cognitive mental state with the mini-mental state examination; urodynamic studies, and gait evaluation. These tests were carried out on admission, and repeated on day 1, day 3, and day 5 after controlled-resistance, continuous lumbar drainage (CRCLD). During this period, eight patients showed significant improvements of cognitive mental state, urodynamic studies, or gait and were regarded as CRCLD responders; the remaining seven patients were regarded as CRCLD non-responders. The CRCLD was routinely removed on day 6 after the drainage procedure and a ventriculoperitoneal (VP) or a lumboperitoneal (LP) shunt was randomly selected for each patient. The tests were repeated one week after shunting and a year later. All the CRCLD responders continued to benefit from shunting at one week and one year after the procedure irrespective of the type of shunting they received. By comparison, none of the CRCLD non-responders showed any improvement a year after the shunting. In conclusion, CRCLD proved to be a safe and effective way to predict the effectiveness of shunting in patients with normal pressure hydrocephalus.

Aged↗
PubMed1994

Functional synergism between multiple thyroid hormone response elements regulates hepatic expression of the rat S14 gene.

Hepatic expression of the rat S14 gene is markedly and rapidly induced in response to T3. Previously, three contiguous restriction fragments of the S14 gene with thyroid hormone response activity were mapped to a region 2.5-3.0 kilobases upstream from the start of transcription [Far Upstream Regulatory region (FUR)]. To further investigate the molecular basis of the thyroid hormonal control of S14 gene expression, we have mapped the functional TRE sequences in the FUR region of the S14 gene. In vitro translated thyroid hormone receptor (TR) and retinoid X receptor were used in the gel retardation assays to map receptor binding sites in the S14 gene. Three TR-binding sequences were identified in the FUR region of the S14 gene and designated: FUR10 (from -2718 to -2694), FUR11 (from -2632 to -2595), and FUR12 (from -2582 to -2558). Each binding site contains two or more elements related to the consensus monomer binding motif 5'-Pu-GGTCA. In FUR10 and FUR12, these motifs were arranged as direct repeats with 4 base pair spacing, while in FUR11 a more complex arrangement occurred. From mutagenesis experiments, all three TR-binding sequences in the S14 gene were found to play a role and synergize with each other in the responsiveness to T3. The importance of this functional synergy is also shown by the observations that at least two TR-binding sites are required for T3 induction in hepatocytes. In addition, synergy occurs between TR and additional regulatory sequences present in the FUR region and provides the maximal T3 response of the S14 gene.

Animals↗
PubMed1994

Sintered porous DP-bioactive glass and hydroxyapatite as bone substitute.

There is extensive experimental and surgical experience with the use of bone tissue to fill defects in the skeleton, to bridge non-union sites, and to pack defects in bone created from cyst curettage. DP-bioactive glass with a chemical composition of Na2O 8.4%, SiO2 39.6%, P2O5 12% and CaO 40% has been reported as an alternative bone substitute of high mechanical strength, good biocompatibility. and which has a tight bond with living tissue. The bonding layer between DP-bioactive glass and bone tissue was considered to be formed by dissolution of calcium and phosphate ions from the DP-bioactive glass into the surrounding body fluids. The biological hydroxyapatite was suspected to deposit directly onto the bonding layer. In order to confirm the interaction between the DP-bioactive glass and bone tissue, the developed bioactive glass was implanted into rabbit femur condyle for 2-32 weeks. The histological evaluation of DP-bioactive glass as a bone substitute was also investigated in the study. Porous hydroxyapatite bioceramic was used in the control group and the results were compared with those of DP-bioactive glass. The interface between the DP-bioactive glass and bone tissue examined with SEM-EPMA showed that the bioactive glass formed a reaction layer on the surface within 2 weeks after operation and formed a direct bond with natural bone. The elements contained in the bioactive glass apparently interdiffuse with the living bone and biological hydroxyapatite deposited onto the diffusion area, which was proved by EPMA and TEM. After implantation for over 8 weeks, the DP-bioactive glass was gradually biodegraded and absorbed by the living bone. Histological examination using the optical microscope showed that osteocytes grow into the inside of the DP-bioactive glass and the bioactive glass would be expected to be a part of bone.

Animals↗
PubMed1994

[Correlation between types of syndrome differentiation and erythrocyte deformability and membrane ATPase activity in psoriatic patients].

Erythrocyte deformability and membrane adenosine triphosphatase (ATPase) activity from 32 psoriatic patients with TCM Syndrome Differentiation-Typing and 30 healthy subjects were observed. The results showed that in Psoriatic patients erythrocyte deformability reduced, and Na(+)-K++ ATPase activity elevated while Ca+(+)-Mg++ ATPase activity decreased. The degree of abnormality was in following order: the group of Blood Stasis > the group of Blood Dryness > the group of Blood Heat, which suggested that there was definitely the sign of Blood Stasis in psoriatic patients. It might be considered as objective index for TCM Syndrome Differentiation and Typing of psoriasis. To guide the treatment of TCM and study the pathogenesis of psoriasis is important.

Adolescent↗
PubMed1994

[The analgesia effect and plasma corticosterone reaction during stress in adult rats treated neonatally with monosodium glutamate].

In the present investigation, it was found that the number of beta-endorphin (beta-END)-immunoreactive neurons of hypothalamic arcuate nucleus (ARC) in MSG-treated rats decreased by 60.7%. No significant differences in the baseline pain threshold and the baseline corticosterone (CS) level were observed between the MSG-treated group and the control group. After electrical foot shock for 30 min, the analgesia effect was decreased significantly (P < 0.001) in MSG-treated rats, while the CS levels of both MSG-treated rats and control rats were increased remarked (P < 0.01). The results suggest that the beta-END neurons of ARC were involved in analgesia, but not in CS reaction during stress.

Animals↗
PubMed1993

Aromatic DNA adducts in brain tumors by 32P-postlabeling analysis.

DNA from human brain tumor samples was analysed by the 32P-postlabeling technique for the presence of aromatic DNA adducts. Thirteen out of 16 samples showed low levels of adducts at 0.14-3.53 adducts per 10(9) nucleotides. Inter-individual variations in the patterns of these aromatic adducts were observed. On the other hand, none of 5 brain samples from epilepsy patients revealed any evidence of such adducts. The data demonstrated the presence of low level, large molecule aromatic DNA adducts in malignant brain tissues and these adducts may either result from environmental exposure to an undetermined genotoxic agent or from the aging process.

Adenoma↗
PubMed1993

Technetium-99m hexamethylpropylene amine oxime single photon emission tomography of the brain in early Parkinson's disease: correlation with dementia and lateralization.

Regional cerebral blood flow was assessed in 19 patients with early idiopathic Parkinson's disease (PD) and 12 control subjects of similar age by single-photon emission tomography using technetium-99m hexamethylpropylene amine oxime (HMPAO). Of the patients with PD, seven were mildly demented and 15 presented with hemiparkinsonism. Mean HMPAO cortical or basal ganglia/cerebellum activity ratios were calculated. Mean cortical and regional uptake ratios in non-demented PD patients were not significantly different from values in the controls. In contrast, besides generalized cortical hypoperfusion, demented PD patients had significantly lower HMPAO uptake in the frontal and basal ganglia regions than non-demented patients. These observations support the hypothesis of impaired neuronal activity in both cortical and subcortical regions of the brain in demented PD patients. In hemiparkinsonian patients, the only asymmetrical finding was a relative hypoperfusion in the contralateral parietal region. This may be due to deafferentation of the thalamoparietal pathways. The lack of asymmetrical uptake in basal ganglia in our PD patients may be explained by their staging at the time of the investigation (stage I and II, Hoehn and Yahr scale).

Aged↗
PubMed1993

Acute adaptation and resetting of the baroreflex control of vascular resistance in the canine hindquarters and mesentery.

To determine whether acute adaptation and resetting occur in the baroreflex control of regional vascular resistance, experiments were conducted in anesthetized and vagotomized dogs. The carotid sinuses were vascularly isolated to regulate the carotid sinus pressure (CSP) in an open-loop fashion. The hindquarters (n = 12) and mesenteric (n = 10) beds were perfused with constant flow and arterial perfusion pressures (HPP and MPP) were used to reflect changes in hindquarters and mesenteric resistance respectively. We first observed alterations in HPP and MPP during the course of CSP holding (conditioning pressure) at various levels for 15 min. Thereafter, the CSP was lowered to 50 mm Hg and increased stepwise to obtain the CSP-HPP and CSP-MPP baroreflex function curves. In experiments in the hindquarters bed, HPP stabilized at an average of 104.7 mm Hg during the initial conditioning pressure at 100 mm Hg. When conditioning pressure decreased to 50 mm Hg, the HPP increased to 125.5 mm Hg and then gradually declined to a steady level (115.6 mm Hg) in 5 min. An increase in conditioning pressure from 100 to 150 mm Hg caused HPP to decrease to 54.8 mm Hg followed by an upward adaptation to a steady level (80.2 mm Hg) in 5 min. The CSP/HPP curves constructed from the CSP step protocol were also affected by conditioning pressure. There were significant increases in the threshold and saturation pressures as conditioning pressure was elevated. However, the resetting was characterized by a parallel shift of the CSP/HPP curves without significant changes in baroreflex gain or sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1993

Preparation and in vivo evaluation of a newly developed bioglass ceramic.

This paper presents details of the fabrication of a glass ceramic, and its application as an artificial bone prosthetic material. This new bioglass ceramic, with composition of Na2O 8.4%, CaO 40.6%, P2O5 12% and SiO2 39%, had 160-190 MPa and 800-980 MPa of three-point bending strength and compressive strength respectively. The ceramic has a (Na, Ca) (P, Si) O3 crystalline phase with a uniform crystal size of about 10 microns, which was attributed to the high nucleation frequency. The rabbit condyle test showed that the material formed a tight chemical bond with biological texture and had good biocompatibility.

Animals↗