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Biomedical subjects

H C Liu

Publications and source records attributed to H C Liu.

At least 217 records · Page 12Linked to original sources
PubMed1993

Rhythmic and patterned neuronal firing in visual cortex.

We present evidence from multi-electrode recordings that the stimulus driven activity in a region of monkey visual cortex displays synchronous, oscillatory behaviour with temporally changing patterns of firing. The spatial-temporal patterns are dependent on cortical layer and on visual stimulus, 'build up and die down' with a period of 70-100 msec, and cannot be factorized into separate spatial and temporal components. This finding supports neural network models which explicitly incorporate spatial-temporal structure, ruling against a purely spatial code for information processing. The new type of analysis presented here is also suitable for direct on-line interactive analysis during multi-electrode recording experiments. Further, it could be modified for use in human EEG or evoked response recordings.

Action Potentials↗
PubMed1993

Creutzfeldt-Jakob disease. Report of a case of the panencephalopathic type and experiences of a teaching hospital in Taiwan.

We report a case of the unusual panencephalopathic type of Creutzfeldt-Jakob disease (CJD) in Taiwan. This 59-year-old woman presented in 1983 with typical clinical manifestations of CJD and died 16 months later. Postmortem examination revealed severe neuronal loss, spongiosis and gliosis extensively in cerebral cortex and striatum as well as in the white matter. We also report 6 other CJD patients seen from 1983 to 1991 at Veterans General Hospital-Taipei.

Aged↗
PubMed1993

Amelioration of antioxidant enzyme suppression and proteinuria in cyclosporin-treated puromycin nephrosis.

The effect of cyclosporin (CS) on intrinsic glomerular level of antioxidants in puromycin aminonucleoside (PAN) nephrosis was examined. A single intravenous dose of PAN (50 mg/kg body weight) given to Sprague-Dawley rats resulted in marked proteinuria. Ten days after PAN injection, the rats were treated with daily intraperitoneal injection of CS (10 mg/kg body weight/day) for 10 days. PAN-treated rats without CS treatment (PAN rats) had significantly lower activities of glomerular superoxide dismutase (SOD) and catalase (CAT) than normal rats (p < 0.05, respectively). When compared with PAN rats, CS-treated PAN rats had significantly less proteinuria and higher activities of glomerular SOD and CAT (p < 0.01 and p < 0.05, respectively). Significant elevation of glomerular malondialdehyde (MDA) level characteristic of PAN rats was absent in CS-treated PAN rats. Moreover, segmental sclerosis with capsular adhesion, hyalinosis, epithelial cell foot process fusion and microvillous transformation seen in PAN rats were apparently attenuated in CS-treated PAN rats. When compared with normal rats, rats receiving CS only had a significantly higher CAT activity and MDA level (p < 0.01 and p < 0.05, respectively). Assessment of glomerular reduced glutathione revealed no significant differences among PAN rats, CS-treated PAN rats, normal rats, and rats receiving only CS. These data indicate that glomerular antioxidant enzyme activities are modulated by CS.

Animals↗
PubMed1993

Posterior ischemia during an attack of transient global amnesia.

BACKGROUND: The popular concept that cerebral ischemia causes transient global amnesia has been difficult to prove by cerebral blood flow studies during attacks because the transient global amnesia attacks are so short. CASE DESCRIPTION: We performed single-photon emission computed tomography (SPECT) of the brain and neuropsychological assessment in a 37-year-old woman during a 10-hour attack and twice thereafter. A neuropsychological evaluation 3 hours after the onset of transient global amnesia revealed severe impairment of recent memory and verbal fluency, both of which returned to normal 2 and 28 days later, respectively. A 99mTc-labeled hexamethylpropyleneamine oxime SPECT of the brain performed 6 hours after the onset showed multiple perfusion defects in both occipital lobes, the medial left temporal lobe, and the left thalamus. A second brain SPECT performed 3 days later showed perfusion defects in only the occipital regions. A third brain SPECT performed 28 days later was normal. The patient's brain computed tomographic scan, electroencephalogram, duplex ultrasound of the carotid artery, and echocardiogram were normal. CONCLUSIONS: The perfusion defects revealed by the brain SPECT during the transient global amnesia attack indicated ischemia in the territory of the posterior cerebral arteries, which partially resolved in 3 days and completely resolved by 28 days.

Adult↗
PubMed1993

[A clinical study of autologous hematopoietic stem cells transplantation in 41 patients with leukemia and other malignant diseases].

41 patients (35 with leukemia, 4 lymphoma, 1 myeloma and 1 neuroblastoma) were treated with autologous hematopoietic stem cells transplantation. 8 patients were treated with autologous bone marrow transplant without purging (ABMT) 15 with autologous bone marrow transplant and purging (pABMT) and 18 with autologous blood hematopoietic stem cells transplant (ABHSCT). The mean hematopoietic reconstitution time was 60, 53, and 29.5 days respectively and the mean GM-CFU recovery time was 37, 44, and 30.5 days respectively in these three groups. The infection complication rates were 37.5%, 26.6% and 16.6% and the relapse rates were 37.5%, 30% and 18.7% respectively in the three groups. The results indicated that the ABHSCT had an earlier hematopoietic reconstitution time, a lesser infection complication rate and a lower relapse rate. Comparing with conventional chemotherapy, all the three transplant groups had an obviously longer disease-free survival time and a better curative effect.

Adolescent↗
PubMed1993

[Hemorrhagic cystitis in the course of hematopoietic stem cell transplantation].

Sixty patients consisting of 56 cases with leukemia, 3 with lymphoma and 1 with neuroblastoma were treated with various kinds of hematopoietic stem cell transplantation. The conditioning regimen consisted of mainly cyclophosphamide (CTX) and total body irradiation (TBI) with the addition of 1-3 doses of other antitumor drugs e.g. cytarabine, daunomycin, etoposide, 6-MP etc. The overall incidence of hemorrhagic cystitis in the course of transplantation was 23.3% (14 out of 60 patients). The time of onset of hematuria in 6 of 14 patients was within 1-4 days following high-dose CTX during conditioning and in the remaining 8 cases occurred 10-30 days after transplantation. The duration of hematuria lasted 2-31 days (mean, 4 days). Thirteen patients recovered and one patient died from the complication.

Adolescent↗
PubMed1993

[A study of temporomandibular joint with retruded closed position of edentulous jaws by CT and MRI].

Bilateral TMJ of 7 edentulous patients were studied by CT in two positions. One position was to make the complete dentures in intercuspal position (ICP) while the other one was to make the edentulous jaws in closed position. Two of them MRI examination was made. It is discovered that the condyles move backward and upward in the glenoid fossa. The displacement of the disc in edentulous closed position is less in comparison with ICP. It is proposed that loss of vertical dimension such as abrasion and loss of dentition may press the disc anteriorly as a result of condyle displacement which it is a causal factor of TMJDS.

Aged↗
PubMed1993

Assisted hatching facilitates earlier implantation.

OBJECTIVE: To examine whether opening of the zona pellucida (i.e., assisted hatching) accelerates implantation. DESIGN: In a controlled, randomized trial, patients were assigned to control and assisted hatching groups. SETTING: All patients studied were of the Center for Reproductive Medicine at Cornell University Medical College. INTERVENTION: All patients underwent stimulation with gonadotropins after luteal phase GnRH down regulation. Assisted hatching with zona drilling using acidic Tyrode's solution was performed on the assigned embryos. MAIN OUTCOME MEASURES: Luteal E2, P, and hCG on days +5, +6, +7, +8, +9, +11, +13, and +15 were measured. The implantation time, peak midluteal E2 and intervals between these two values were studied. RESULTS: Implantation occurred significantly earlier in the assisted hatching group. The interval between implantation and peak midluteal E2 was also significantly shorter in the assisted hatching group than in the controls. However, there was no significant difference in the day of the peak midluteal E2 between the assisted hatching and control groups. CONCLUSION: Assisted hatching may enhance embryo implantation not only by mechanically facilitating the hatching process but also by allowing earlier embryo-endometrium contact. Such early contact may enhance embryonic development potential and may optimize synchronization between embryo and endometrium, resulting in improved implantation efficiency.

Chorionic Gonadotropin↗
PubMed1993

Relationship between periventricular lucencies on computed tomographic scans and vascular dementia.

We evaluated 48 consecutive patients with periventricular lucencies (PVL) on CT scan of brain to determine the clinical significance of this finding. Twenty-one (43.7%) patients were demented; 27 (56.3%) patients had no dementia but had various other diseases. PVL were frequently associated with hypertension and previous stroke. We used a PVL scoring system to evaluate the degree of PVL. When the score was greater than 3.5, the sensitivity and specificity in separating vascular dementia from other diseases with PVL were 78% and 67% respectively (Kappa = 0.42). We conclude that although mild PVL may be a frequent but non-specific finding in patients with hypertension or previous stroke, moderate and severe PVL should raise the possibility of vascular dementia.

Age Factors↗
PubMed1993

Hepatocellular carcinoma in Taiwan: clinicopathological study of 440 cases from a consecutive 6000 autopsies.

The clinico-pathological features of 440 autopsy cases of hepatocellular carcinoma collected in a 30-year period were analyzed. The statistical observations included sex, age, clinical presentations, initial symptoms and signs, physical findings, varices, ascites, alpha-fetoprotein, serum hepatitis B surface antigen, liver weight, gross anatomic and histologic features of the tumors, grade of anaplasia, changes in noncancer parenchyma, and survival. Multivariate analyses demonstrated that age, HBsAg, AFP, associated cirrhosis, liver weight, gross pathology, histologic grading and structural pattern, and presence of clear cells did not correlate to the prognosis. The presence of metastasis adversely influenced the outcome. Bile production was associated with better tumor differentiation and longer patient survival. It also found that the smaller tumor tended to be more well differentiated.

Adolescent↗
PubMed1992

Primary intracranial germ cell tumor. Pathologic study of 51 patients.

Fifty-one primary intracranial germ cell tumors (GCT), including germinoma, teratoma, endodermal sinus tumor, choriocarcinoma and mixed GCT, were studied. The incidence of GCT in the surgically removed intracranial neoplasms was 11.1% for pediatric patients and 0.6% for adult patients. The age/sex of the patients and the location of the tumors were analyzed. Morphologic findings of these tumors were identical to that of their gonadal counterparts. Immunohistochemical studies showed that alpha-fetoprotein (alpha-AFP), human chorionic gonadotropin (HCG), and placental alkaline phosphatase (PLAP) were helpful, whereas carcinoembryonic antigen (CEA) and cytokeratin (CKER) were of little help in determining the diagnosis. Serum tumor markers, alpha-AFP and HCG, were helpful in recognizing GCT producing them. However, they could not be used for specific diagnosis because different tumors could have similar serum levels. Histopathologic study was handicapped by the small size of most specimens (which usually could not include all of the components if the tumor was a mixed GCT), but it was the only means for specific diagnosis.

Adolescent↗
PubMed1992

Comparative study of the prognostic value of nuclear grade and silver-binding nucleolar organizer region in renal cell carcinomas.

Silver-binding nucleolar organizer region (AgNOR) and nuclear grade were histologically assessed in 112 renal cell carcinomas. Nuclear grade was better capable of stratification than AgNOR in terms of survival prediction. It also had prognostic significance when total metastatic rates were evaluated. Although higher mean AgNOR numbers were constantly associated with higher nuclear grades, two arbitrary classifications of AgNOR (less than 1.5, 1.5-3.5, greater than 3.5; less than 2, 2-3, greater than 3) failed to resolve the survival difference.

Carcinoma, Renal Cell↗
PubMed1992

Microsurgical fertilization procedures: the absence of stringent criteria for patient selection.

Subzonal sperm insertion and partial zona dissection were applied in 250 in vitro fertilization cycles in couples (n = 200) with abnormal semen analyses; 61 clinical pregnancies were established (24% per egg retrieval). Patients were selected without using minimal cutoff criteria. The study included patients with 0% normal sperm forms (strict criteria), no motile sperm (but some live cells), and sperm counts which could be assessed only after centrifugation. Patients were categorized into three subsets. Group A (n = 116 cycles) failed to fertilize in a previous cycle. Group B (n = 40) was excluded from IVF due to the severity of sperm profiles, such as a maximum of 2% normal forms. Group C (n = 94) constitutes those patients for whom a standard cycle could possibly result in failure. Monospermic fertilization rates were 18% (A), 19% (B), and 24% (C). The incidences of embryo replacement were 63% (A), 53% (B), and 69% (C). Rates of clinical pregnancy were 22% (A), 23% (B), and 28% (C). The presence of one, two, or three semen abnormalities did not correlate with the outcome of microsurgical fertilization. Twenty-two percent of patients with combined oligoasthenoteratozoospermia became pregnant. Moreover, ongoing pregnancies were established in instances with 0% normal sperm forms and no progressively motile spermatozoa. It is concluded that stringent cutoff criteria may not be necessary when both partial zona dissection and subzonal sperm insertion are performed efficiently.

Culture Techniques↗
PubMed1992

Improved pregnancy outcome with gonadotropin releasing hormone agonist (GnRH-a) stimulation is due to the improvement in oocyte quantity rather than quality.

The impact of gonadotropin releasing hormone agonist (GnRH-a) on the quality and quantity of oocytes harvested in in vitro fertilization-embryo transfer (IVF-ET) patients was studied by comparing the results for patients stimulated with gonadotropin alone and with gonadotropin plus GnRH-a. Adding GnRH-a significantly improved the viable pregnancies per transfer and reduced the spontaneous abortions, which seemed to improve oocyte quality. However, when oocyte quality was evaluated by the fertilization rate and the implantation and delivery rates per embryos transferred, there were no significant difference in the results, indicating that GnRH-a did not improve the oocyte quality. On the other hand, GnRH-a significantly increased the average number of oocytes harvested, fertilized, and transferred, and this increased number of oocytes transferred has been demonstrated to increase pregnancy and multiple-pregnancy rates. Multiple pregnancy with more embryos implanted would significantly reduce the abortion rate. Abortion rates decreased inversely to the number of embryos implanted. Our data strongly suggest that the efficacy of GnRH-a on IVF-ET patients was due more to the quantity increase than the quality of embryos transferred.

Embryo Implantation↗
PubMed1992

Debrisoquine metabolism in Chinese patients with Alzheimer's and Parkinson's diseases.

We determined the oxidative phenotype and metabolic ratio of debrisoquine in 96 Chinese patients with Alzheimer's disease (n = 12), Parkinson's disease (n = 55), and using patients with stroke and cervical spondylosis as controls (n = 29). We did not find any difference in debrisoquine metabolic phenotype among Parkinson's disease, Alzheimer's disease, and control patients as judged by chi-square analysis. In addition, the metabolic ratio of all our patients was less than 12.6. The result suggested that Chinese patients with Parkinson's disease and Alzheimer's disease metabolize debrisoquine at a velocity not different from that of their Western counterparts even though the frequency distribution of debrisoquine metabolism phenotyping in these two populations is quite different.

Aged↗
PubMed1992

Correlation of nocturnal increase in plasma oxytocin with a decrease in plasma estradiol/progesterone ratio in late pregnancy.

OBJECTIVES: Our purpose was to determine whether plasma oxytocin concentrations show a daily rhythm. STUDY DESIGN: Ten women between 37 and 39 weeks of gestation volunteered for the study. They were admitted 1 to 2 days before the experiment. Three blood samples were taken with 2-minute intervals each time, at 8 AM, 4 PM, and 12 midnight. Oxytocin, 17 beta-estradiol, progesterone, and cortisol were measured by radioimmunoassay with highly specific antibodies. Statistical analysis of variance by Friedman's test was followed by multiple range testing, and p < 0.05 was considered significant. RESULTS: Significant daily rhythm was found for plasma cortisol, progesterone, and oxytocin and for the estradiol/progesterone ratio. Oxytocin showed a nocturnal peak and a strong negative correlation with the estradiol/progesterone ratio. CONCLUSIONS: The daily rhythm in plasma oxytocin parallels the rhythm in uterine activity (shown by others), suggesting a causal relationship between the two. Both may in turn be related to the ratio of circulating estradiol and progesterone.

Circadian Rhythm↗
PubMed1992

Prolactin-containing pituitary adenomas. Their characteristics and comparative study with non-prolactin adenomas.

Immunohistochemical study of 130 pituitary adenomas shows that 31% are prolactin-containing adenomas, two-thirds of which are monohormonal adenomas, i.e. prolactin cell adenoma, and one-third are multihormonal adenomas, i.e. mixed growth hormone cell-prolactin cell adenoma and plurihormonal adenoma with prolactin. Clinical symptoms including amenorrhea and galactorrhea are not useful in distinguishing prolactin from non-prolactin adenomas. Serum prolactin concentration of 80 ng/ml is a good cut-off point to distinguish prolactin cell adenoma from non-prolactin adenoma but can not separate many of the multihormonal adenomas from non-prolactin adenomas. Calcification is not only more commonly seen but also more prominent in prolactin-containing adenomas. Spheroid amyloid is present in one prolactin cell adenoma. Immunohistochemistry is specific and reliable in identifying prolactin-containing adenomas. All prolactin cell adenomas and 2/13 multihormonal adenomas show paranuclear staining of prolactin in almost every adenoma cell. The remaining (11/13) multihormonal adenomas show less prolactin cells and diffuse cytoplasmic staining of prolactin. The prolactin staining pattern in the latter group is unique and appears to be indicative of the presence of other hormone(s).

Adenoma↗