Search PubMed⌕ Search

Biomedical subjects

C Y Liu

Publications and source records attributed to C Y Liu.

At least 163 records · Page 9Linked to original sources
PubMed1996

Increasing antibiotic resistance in clinical isolates of Aeromonas strains in Taiwan.

A total of 234 clinical isolates of Aeromonas, primarily A. hydrophila, were collected for the present study. Most were isolates from blood. By the agar dilution method, more than 90% of the Aeromonas strains were found to be susceptible to moxalactam, ceftazidime, cefepime, aztreonam, imipenem, amikacin, and fluoroquinolones, but they were more resistant to tetracycline, trimethoprim-sulfamethoxazole, some extended-spectrum cephalosporins, and aminoglycosides than strains from the United States and Australia.

Aeromonas↗
PubMed1996

Attenuation of endothelin-1-induced calcium response by tyrosine kinase inhibitors in vascular smooth muscle cells.

Although tyrosine kinases play an important role in cell growth and have been implicated in regulation of smooth muscle contraction, their role in agonist-induced myoplasmic Ca2+ responses is unclear. We examined effects of the tyrosine kinase inhibitors genistein and methyl 2,5-dihydroxycinnamate (MDHC) on the endothelin-1 (ET-1)-induced Ca2+ response and determined underlying mechanisms for the effects. Freshly isolated smooth muscle cells from porcine coronary arteries were loaded with fura 2 ester, and myoplasmic free Ca2+ (Ca2+ (m)) concentration was estimated with fura 2 microfluorometry. Both genistein and MDHC inhibited the initial transient Cam2+ response to ET by 54 and 81%, respectively (P < 0.05), in the presence of extracellular Ca2+. Genistein also significantly delayed the Cam2+ response, with the latent period from ET-1 application to the beginning of the Cam2+ response being increased from 1.08 +/- 0.17 to 2.65 +/- 0.52 min (P < 0.05). In the absence of extracellular Ca2+, genistein inhibited the ET-1-induced Cam2+ response by 93% (P < 0.05). The Cam2+ responses to caffeine (5 mM) or inositol trisphosphate (IP3) applied intracellularly via a patch-clamp pipette were not affected by genistein. Both genistein and MDHC also abolished the sustained Cam2+ response to ET-1. However, the Cam2+ response to depolarization by 80 mM K+ was not inhibited by MDHC and only inhibited 22% by genistein (P < 0.05). These results indicate that 1) activation of tyrosine kinases is an important regulatory mechanism for the ET-1-induced Cam2+ response in vascular smooth muscle and 2) tyrosine kinases mediate ET-1-induced Ca2+ release with no direct effect on IP3-mediated Ca2+ release. Thus ET-1-mediated signaling upstream of IP3 interaction with the Ca2+ stores is regulated by tyrosine kinases.

Animals↗
PubMed1996

Pharmacokinetics and pharmacodynamics of metformin in healthy subjects and patients with noninsulin-dependent diabetes mellitus.

This study was conducted to assess the effect of noninsulin-dependent diabetes mellitus (NIDDM) and gender on the pharmacokinetics of metformin and to investigate whether or not metformin exhibits dose-dependent pharmacokinetics. The pharmacodynamic effects (on plasma glucose and insulin) of metformin in patients with NIDDM and in healthy subjects also were assessed. Nine patients with NIDDM and 9 healthy subjects received 4 single-blind single-dose treatments of metformin HCL (850 mg, 1,700 mg, 2,550 mg, and placebo) and a multiple-dose treatment of 850 mg metformin HCL (3 times daily for 19 doses). After each single-dose treatment and the final dose of the multiple-dose phase, multiple plasma and urine samples were collected for 48 hours and assayed for metformin levels. Plasma samples were also assayed for glucose and insulin levels. There were no significant differences in metformin kinetics in patients with NIDDM compared with healthy subjects, in men compared with women, or during multiple-dose treatment versus single-dose treatment. Plasma concentrations of metformin increase less than proportionally to dose, most likely due to a decrease in percent absorbed. In patients with NIDDM, single doses of 1,700-mg or higher of metformin significantly decrease postprandial, but not preprandial, glucose concentrations and do not influence insulin concentrations. With multiple doses, both preprandial and postprandial glucose concentrations and preprandial insulin concentrations were significantly lower than with placebo. The effect of metformin on glucose level is correlated with the average fasting plasma glucose level without drug. In healthy subjects, single and multiple doses of metformin showed no effect on plasma glucose, but significantly attenuated the rise in immediate postprandial insulin levels.

Adult↗
PubMed1996

Suicide and parasuicide in psychiatric inpatients: ten years experience at a general hospital in Taiwan.

We investigated 64 suicidal acts of 62 psychiatric inpatients over a 10-yr. period. The findings indicated the frequency of suicidal behavior of psychiatric inpatients was 0.91% of total admissions, two thirds of the patients who attempted suicide were diagnosed with schizophrenia or depression, and patients suffering from depression, substance abuse, and personality disorders had a higher parasuicide rate, among whom those diagnosed bipolar disorder with depressive episode had an extremely high parasuicide rate. Most of the incidents occurred in concealed places, and most of the patients used nonviolent methods. About half of the incidents occurred during the evening shift and depressed patients tended to attempt suicide during the night shift. Most suicidal attempts were unsuccessful and led to minor injury. There were two deaths.

Adult↗
PubMed1996

Bipolar disorder following a stroke involving the left hemisphere.

OBJECTIVE: Post-stroke mania has rarely been noted and researched, and reported cases have mostly involved the non-dominant hemisphere. In this paper, we report a case of bipolar disorder secondary to a stroke over the dominant hemisphere. CLINICAL PICTURE: A 48-year-old, right-handed man had a cerebral infarct over the left temporal region. He became depressed after the stroke, and 4 months later developed a manic episode. TREATMENT: The patient was treated with haloperidol and lorazepam. OUTCOME: The symptoms subsided within 2 months after treatment. CONCLUSIONS: It is premature to consider mania to be a syndrome of the right, or non-dominant, hemisphere. We suggest that further study focusing on specific anatomical regions, rather than laterality, will help to elucidate the interrelationship between mood and brain function.

Bipolar Disorder↗
PubMed1996

Transfusion-acquired AIDS in Taiwan.

Human immunodeficiency virus type 1 (HIV-1) can be transmitted through blood transfusion. The first transfusion-acquired immunodeficiency syndrome (AIDS) patient in Taiwan was a 46-year-old woman who received two units of whole blood during a hysterectomy at a provincial hospital in 1985. In 1991, she experienced a herpes zoster infection. In March 1993, she had extensive herpetic gingivostomatitis and another herpes zoster attack, and was treated at the same hospital. Two months later, she had oral candidiasis and was treated at a medical center. She was not tested for HIV-1 infection until she developed Pneumocystis carinii pneumonia in June 1993. In February 1994, and developed cytomegalovirus retinitis and died 6 months later. Donor blood given to the patients during the hysterectomy was HIV-1 positive. The donor's HIV infection was discovered in 1991 and he died of AIDS in 1993. As blood centers in Taiwan did not start screening for HIV-1 until January 1988, it is urgently recommended that any individual who received a blood transfusion between 1984 and 1987 in Taiwan and who currently experiences repeated episodes of opportunistic infections have an HIV-1 blood test. The receipt of a blood transfusion between 1984 and 1987 should be listed by the Department of Health as an indication for HIV-1 screening.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Infections in febrile granulocytopenic patients: clinical features and pathogens.

From 1990 to 1994, we prospectively evaluated patients with cancer or aplastic anemia who had granulocyte counts of less than 500/mm3 and fever, in order to study infections in febrile granulocytopenic patients in Taiwan. A total of 100 episodes in 95 patients were evaluated. Aerobic Gram-negative bacilli were responsible for 72.5% of the 80 organisms identified in the infections. Escherichia coli was the most common isolate, accounting for 46.5% of Gram-negative bacilli. Pseudomonas aeruginosa and Klebsiella spp caused 24.1% and 18.9% of these infections, respectively. Aerobic Gram-positive cocci were responsible for 12.5% of the 80 organisms identified in the infections. Fungal infections were responsible for 8.8% of isolates. Septicemia, predominantly due to Gram-negative bacilli, accounted for 39 episodes. Infection sites included the respiratory tract, urinary tract, skin and soft tissue, oral cavity, intestines, anus and ear canal. Identification of the pathogens and their clinical features is important in the immediate treatment of such infections.

Adolescent↗
PubMed1996

The different effect of salbutamol and aminophylline on platelet activating factor-induced plasma exudation into guinea pig tracheal wall and lumen.

We examined the effects of salbutamol, aminophylline and verapamil on plasma exudation into airway wall and lumen in guinea pig trachea isolated in situ. Platelet-activating factor (PAF) (50 ng/kg) induced plasma exudation into both the tissue and lumen. Aminophylline (25 mg/kg) eliminated PAF-induced plasma leakage in the tissue and lumen. Verapamil (500 micrograms/kg) had neither effect. Salbutamol (160 micrograms/kg) significantly reduced PAF-induced plasma exudation in the tissue and enhanced plasma recovery in the airway lumen. We conclude that aminophylline inhibited microvascular leakage whereas salbutamol facilitates exudated plasma across epithelium and reduced its accumulation in the tissue.

Adrenergic beta-Agonists↗
PubMed1996

Collagen in naturally occurring hypertrophied porcine myocardium.

A comparison of the collagen network in three dimensions was conducted in 8 hypertrophic cardiomyopathy (HCM)-affected and 8 normal hearts. All these hearts were obtained from male and age-matched pigs of the same breeding farm under identical feeding conditions. The selection of HCM-affected heart was based on the abnormal histologic features such as marked disorientation of muscle cells, thickening of the intramural coronary arterial wall with a narrowed lumen, endocardial fibrosis, and myocardial fibrosis. Mean values of heart weight and ratio of heart to body weight of HCM group were significantly (p < 0.01) increased by 36% and 47%, respectively, but not the body weight, as compared to those of the normal group. The scanning electron microscopic (SEM) investigation demonstrated that collagen weave, struts, and strands appeared more numerous in HCM-affected myocardium than in normals. Moreover, the tendons of collagen in HCM-affected myocardium showed increases in both numbers and thickness.

Animals↗
PubMed1996

Keratin 12-deficient mice have fragile corneal epithelia.

PURPOSE: Expression of the K3-K12 keratin pair characterizes the corneal epithelial differentiation. To elucidate the role of keratin 12 in the maintenance of corneal epithelium integrity, the authors bred mice deficient in keratin 12 by gene-targeting techniques. METHODS: One allele of murine Krt1.12 gene was ablated in the embryonic stem cell line, E14.1, by homologous recombination with a DNA construct in which the DNA element between intron 2 and exon 8 of the keratin 12 gene was replaced by a neo-gene. The homologous recombinant embryonic stem cells were injected to mouse blastocysts, and germ lines of chimeras were obtained. The corneas of heterozygous and homozygous mice were characterized by clinical observations using stereomicroscopy, histology with light and electron microscopy, Western immunoblot analysis, immunohistochemistry, in situ hybridization, and Northern hybridization. RESULTS: The heterozygous mice (+/-) one allele of the Krt1.12 gene appear normal and do not develop any clinical manifestations (e.g., corneal epithelial defects). Homozygous mice (-/-) develop normally and suffer mild corneal epithelial erosion. Their corneal epithelia are fragile and can be removed by gentle rubbing of the eyes or brushing with a Microsponge. The corneal epithelium of the homozygote (-/-) does not express keratin 12 as judged by immunohistochemistry, Western immunoblot analysis with epitope-specific anti-keratin 12 antibodies, Northern hybridization with 32P-labeled keratin 12 cDNA, and in situ hybridization with an anti-sense keratin 12 riboprobe. Light and electron microscopy revealed subtle abnormalities in the corneal epithelia of -/- mice (i.e., a decrease in number of cell layers) and cytolysis of superficial cells, but the number of hemidesmosomes and desmosomes are normal in basal and suprabasal cells. The number of keratin intermediate filaments in basal and suprabasal corneal epithelial cells in -/- mice decreases, and they appear as dense bundles. This morphology is similar to that of keratin intermediate filaments in epidermal epithelial, cells but differs from that of normal corneal epithelial cells in which the keratins form fine filamentous networks. The superficial epithelial cells are devoid of keratin intermediate filaments and often detach from the corneal surface of -/- mice. CONCLUSIONS: The presence of cornea-specific K3-K12 keratin pairs is essential for the maintenance of corneal epithelium integrity.

Animals↗
PubMed1995

Kidney function and age are both predictors of pharmacokinetics of metformin.

The effects of renal impairment and age on the pharmacokinetics of metformin were evaluated. The subjects, including 6 young, 12 elderly, and 3 middle-age healthy adults and 15 adults with various degrees of chronic renal impairment (CRI) each were given a single, 850-mg metformin HCl tablet. Multiple whole blood, plasma, and urine samples were collected and analyzed for metformin levels using a high-performance liquid chromatography (HPLC) method. In healthy elderly individuals, the plasma and whole blood clearance/absolute bioavailability values [CL/F and (CL/F)b], and corresponding renal clearance values (CLR and CLR,b) of metformin were 35-40% lower than the respective values in healthy young individuals. These two groups did not differ significantly with respect to volume of distribution (Vd), time to peak concentration (tmax), and parameters related to metformin's appearance in the urine. In the moderate and severe CRI groups, all clearance values were 74-78% lower than in the healthy young/middle-age group, and all other evaluable pharmacokinetic parameters (with the exception of tmax) differed significantly in this group. In the mild CRI group, clearance values of metformin, which were 23-33% lower than in the young/middle-age group, were the only parameters that differed significantly. Based on a regression analysis of the combined data, both creatinine clearance (CL*cr; corrected for body surface area) and age are predictors of metformin clearance, with the following model best fitting the data: CL/F [or (CL/F)b, CLR, CLR,b] = alpha + beta.CL*cr + gamma.CL*cr.age. Metformin should not be used in patients with moderate and severe CRI, or in patients with mild, but not absolutely stable, renal impairment. The initial and maximum doses in elderly patients and patients with stable mild CRI should be lowered to approximately one third that given to the general (i.e., patients without non-insulin-dependent diabetes) population.

Adult↗
PubMed1995

Oxygen transport in thin layers of packed sickle erythrocytes.

A diffusion cell was used to examine the effect of HbS polymerization on the oxygen effective diffusivity, Deff, in packed sickle erythrocytes compared to that in packed normal erythrocytes at 25 degrees. In increasing PO2 experiments, the samples were fully oxygen saturated after a very brief transient. In decreasing PO2 experiments, the average oxygen tension decreased progressively over the time course of the experiment. At full oxygen saturation, Deff in the packed sickle erythrocyte samples was not significantly different from that in normal erythrocytes and was in agreement with prior workers' measurements of unfacilitated oxygen diffusion. Deff measured in the decreasing PO2 experiments on packed sickle erythrocytes was significantly different from that in normal erythrocytes. As the average oxygen tension decreased, Deff in packed normal erythrocytes increased to a maximum of 40% over its unfacilitated value and then decreased. In contrast, in sickle erythrocytes which contained over 90% HbS, as PO2 decreased, Deff increased only slightly and then decreased dramatically. The results of decreasing PO2 experiments on sickle erythrocytes containing significant amounts of other hemoglobins (HbF, HbC) were different from those of both the normal erythrocytes and sickle erythrocytes with dominant HbS fraction, showing the effect of hemoglobin composition on effective diffusivity. These results demonstrate a dramatic effect of HbS polymerization on the resistance to oxygen transport in sickle erythrocytes.

Anemia, Sickle Cell↗
PubMed1995

Production of fumonisins by Fusarium species of Taiwan.

Twenty-nine Fusarium species isolated from various sources in different districts of Taiwan were tested for their ability to produce fumonisins in corn cultures. Only Fusarium moniliforme produced fumonisin B1 (FB1) and fumonisin B2 (FB2). The finding that the other 28 Fusarium species produced neither FB1 nor FB2 is preliminary because only one strain per species was studied. The detection of FB1 and FB2 in cultures of F. moniliforme was demonstrated by TLC and HPLC, and FB1 was further confirmed by mass spectrometry. In a separate experiment, in which 38 strains of F. moniliforme were tested for fumonisins, approximately 66% (25/38) produced FB1 and/or FB2. Of the 25 strains, 14 produced only FB1 and 11 produced both FB1 and FB2, and the amounts of FB1 and FB2 produced by different strains varied greatly. This is the first report that fumonisins are found in corn cultures experimentally infected with F. moniliforme strains from Taiwan. It is safe to assume that fumonisin producing strains of F. moniliforme are widely distributed among the economic crops such as corn, rice, sugarcane, and sorghum throughout the Island.

Food Microbiology↗
PubMed1995

Pharmacokinetics of oral extended-release dosage forms. I. Release kinetics, concentration, and absorbed fraction.

In this study, we derive pharmacokinetic models for oral extended-release (OER) drug products with defined in vivo release kinetics (IVRK) and a compartmental system. Fitting the model to clinical data, we were able to examine the correlation between released and absorbed fractions. Furthermore, we found that absorbed fractions of OER products can be expressed by absorption rate and release duration only. The expression is unchanged in different compartmental systems with the same IVRK, implying that the IVRK drives the pharmacokinetic system of an OER product. The apparent absorption rate constant of an OER product can be estimated by solving an implicit equation using observed concentrations. We also propose a new method for calculating absorbed fractions, which is more accurate than Loo-Riegelman method. Ultimately, these methods may permit optimally designed OER products.

Absorption↗
PubMed1995

Pharmacodynamic analysis of analgesic clinical trials using empirical methods.

Data from analgesic clinical trials have characteristics such as ordered categorical longitudinal responses with repeated measures, delay of effect with respect to analgesic plasma concentration, and right-hand censoring of response due to remedication. In order to determine the concentration-effect relationship of such data, we propose convolving an empirical function for plasma concentration, in the form of broken lines which connect each pair of neighboring observations, with a monoexponential function, to generate "effect site concentration." Effect site concentration and time are used, simultaneously, as independent variables in the fit of the model for the logit of the probability of having a specific pain relief (PR) score at each time point pre-remedication, via maximum likelihood. Using corresponding effect site concentration, the probabilities of having specific PR scores post-remedication are predicted via the concentration-response relationship established. The overall (pre- and post-remedication) predictions and corresponding standard errors for the responses are then estimated. Inference of the PR scoring, using a posterior method, is proposed. An illustration using real data is used to demonstrate these methods.

Analgesics↗
PubMed1995

Comparison of adult manifestations of schizophrenia with onset before and after 15 years of age.

We examined 19 adult cases of early-onset schizophrenia (onset before age 15) and 19 controls (schizophrenia with onset between age 15 and 35). Being matched by sex, length of hospitalization and living environment while the present age between groups showed no difference, patients were compared on psychopathological symptom measures and intelligence quotient (IQ). Results showed that early-onset cases scored significantly higher on Scales for the Assessment of Negative Symptoms and had lower performance IQ. No group difference in positive symptoms measure from Brief Psychiatric Rating Scale and full IQ was noted. It suggested that when early-onset patients grew up, phenomenologically, they resembled the schizophrenia of usual early-adult onset in the positive symptom dimension, but with more negative symptoms, which may be fundamental in this group of patients.

Adolescent↗
PubMed1995

Characterization of a novel 350-kilodalton nuclear phosphoprotein that is specifically involved in mitotic-phase progression.

A gene assigned to human chromosome 1q32-41 encodes a novel protein of 3,113 amino acids containing an internal tandem repeat of 177 amino acids. The protein, which we have named "mitosin," was identified by direct binding to purified retinoblastoma protein in vitro with a region distantly related to the retinoblastoma protein-binding site of E2F-1. Mitosin is expressed throughout S, G2, and M phases of the cell cycle but is absent in G1. Its localization is dramatically reorganized from a rather homogeneous nuclear distribution in S phase to paired dots at the kinetochore/centromere region, to the spindle apparatus, and then to the midbody during M-phase progression. This spatial reorganization coincides closely with the temporal phosphorylation patterns of mitosin. Overexpression of N-terminally truncated mutants blocks cell cycle progression mainly at G2/M. These results suggest that mitosin may play an important role in mitotic-phase progression.

Amino Acid Sequence↗