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Biomedical subjects

Y C Liu

Publications and source records attributed to Y C Liu.

At least 109 records · Page 6Linked to original sources
PubMed1999

Nonalcoholic fatty liver disease: a spectrum of clinical and pathological severity.

BACKGROUND & AIMS: The spectrum of nonalcoholic fatty liver disease ranges from fatty liver alone to nonalcoholic steatohepatitis. Most previous studies have short follow-up and have not carefully delineated different histological types when determining clinical outcomes. The aim of this study was to compare clinical characteristics and outcomes of patients with different types of nonalcoholic fatty liver. METHODS: All liver biopsy specimens from 1979 to 1987 with fat accumulation were assessed for inflammation, ballooning degeneration, Mallory hyaline, and fibrosis. Biopsy specimens were also assessed for histological iron and hepatitis C RNA. Outcomes were cirrhosis, mortality, and liver-related mortality. RESULTS: Of 772 liver biopsy specimens, complete data were available in 132 patients. Fatty liver (type 1) did not differ from the other three types combined with respect to gender, race, age, or obesity. Cirrhosis was more common in the other types combined (22%) than fatty liver alone (4%; P </= 0.001). Overall mortality, histological iron, and hepatitis C did not differ between groups. Most of the liver-related deaths were in type 4. CONCLUSIONS: The outcome of cirrhosis and liver-related death is not uniform across the spectrum of nonalcoholic fatty liver. These poor outcomes are more frequent in patients in whom biopsies show ballooning degeneration and Mallory hyaline or fibrosis.

Adult↗
PubMed1999

Neuronal Fos activation in olfactory bulb and forebrain of male rats having erections in the presence of inaccessible estrous females.

Volatile odors from estrous female rats are necessary and sufficient to induce non-contact penile erections in male rats. It is not known whether these pheromones are detected by the accessory as opposed to the main olfactory system or whether they are processed by forebrain regions that receive olfactory inputs. Using nuclear Fos immunoreactivity as a marker of neuronal activation, we asked how the detection and processing of distal cues from inaccessible estrous females, which elicited non-contact penile erections, compared with the processing of sensory cues from soiled estrous bedding which did not elicit non-contact penile erections. In Experiment 1, groups of sexually experienced males were given one of five treatments. A control group was placed on clean bedding. A second group displayed non-contact penile erections when exposed to the smell, sight and sound of an estrous female restrained behind a permeable barrier. A third group was exposed to the same stimuli as the second (an estrous female) but failed to exhibit non-contact penile erections during the first hour of testing. A fourth group was placed on soiled estrous bedding, and a fifth group was allowed two ejaculations with an estrous female. All males were perfused with 4% paraformaldehyde 2 h after the onset of these respective treatments, and their brains were later processed for Fos immunoreactivity. Non-contact penile erections were observed in males that were exposed to distal cues from an estrous female but not in males exposed to soiled estrous bedding. Males that displayed non-contact penile erections or that were exposed to estrous bedding showed significantly more neuronal Fos immunoreactivity than clean-bedding controls in the nucleus accumbens core and shell, anterior and posterior medial amygdala, bed nucleus of the stria terminalis and the medial preoptic nucleus. Even greater neuronal Fos responses occurred in these regions in mated males. In Experiment 2 these same treatments were given to another cohort of sexually experienced males. Increased neuronal Fos immunoreactivity was observed in the granule and mitral cell layers of the accessory olfactory bulb of males that were either mated or exposed to estrous bedding, but not in males that displayed non-contact penile erections in response to distal cues from an estrous female. The volatile odors which presumably caused non-contact penile erections failed to stimulate significant neuronal Fos immunoreactivity in five main olfactory bulb sites examined. Even so, it seems likely that these pheromones are detected via the main olfactory system and are subsequently processed by the same projection circuit that responds to other pheromones present in estrous bedding that are incapable of eliciting non-contact penile erections.

Animals↗
PubMed1999

Detection of antimicrobial activity in urine for epidemiologic studies of antibiotic use.

Antibiotic resistance is the inevitable consequence of the selective pressure of antimicrobial drug use and the adaptive plasticity of the microorganisms. Excessive and irrational use of antimicrobial drugs is a problem in all countries. It is particularly troublesome in developing countries where there is a heavy burden of infectious diseases. This study was designed to determine whether detection of antimicrobial activity in the urine might be a useful tool for epidemiologic studies of the interaction between antibiotic use and resistance in developing countries. A laboratory marker is necessary because the history of antimicrobial drug use may be unreliable. Serial specimens or spontaneously voided urine were obtained from healthy volunteers given a single oral dose of commonly used antimicrobial drugs. Urine was also obtained from hospitalized patients the morning after the last dose of an antimicrobial drug and from untreated controls. Assays were performed with standard American Type Culture Collection (Rockville, MD) stains of Bacillus stearothermophilus, Escherichia coli, and Streptococcus pyogenes. Antimicrobial activity could not be detected in pretreatment urine. After a single oral dose, the beta lactam antibiotics and erythromycin could be detected for about 12 to 24 hours, whereas clindamycin, tetracycline, trimethoprim/sulfamethoxazole, and ciprofloxacin could be detected for 48 or more hours. In hospitalized patients, receiving multiple drugs, the following were the sensitivity and specificity for detection of antimicrobial activity: for B. stearothermophilus, 100.0% and 85.9%, respectively; for S. pyogenes, 94.9% and 94.9%, respectively; and for E. coli, 71.8% and 98.7%, respectively. The combination of E. coli and Streptococcus pyogenes exhibited a sensitivity of 97.4% and specificity of 94.9%. Detection of antimicrobial activity in urine is a promising method to determine antimicrobial drug use in epidemiologic studies, particularly in populations in which drug use history is unreliable.

Adult↗
PubMed1999

Neuroregulation by vasoactive intestinal peptide (VIP) of mucus secretion in ferret trachea: activation of BK(Ca) channels and inhibition of neurotransmitter release.

1. The aims of this study were to determine: (1) whether vasoactive intestinal peptide (VIP) regulates cholinergic and 'sensory-efferent' (tachykininergic) 35SO4 labelled mucus output in ferret trachea in vitro, using a VIP antibody, (2) the class of potassium (K+) channel involved in VIP-regulation of cholinergic neural secretion using glibenclamide (an ATP-sensitive K+ (K(ATP)) channel inhibitor), iberiotoxin (a large conductance calcium activated K+ (BK(ca)) channel blocker), and apamin (a small conductance K(ca) (SK(ca)) channel blocker), and (3) the effect of VIP on cholinergic neurotransmission using [3H]-choline overflow as a marker for acetylcholine (ACh) release. 2. Exogenous VIP (1 and 10 microM) alone increased 35SO4 output by up to 53% above baseline, but suppressed (by up to 80% at 1 microM) cholinergic and tachykininergic neural secretion without altering secretion induced by ACh or substance P (1 microM each). Endogenous VIP accounted for the minor increase in non-adrenergic, non-cholinergic (NANC), non-tachykininergic neural secretion, which was compatible with the secretory response of exogenous VIP. 3. Iberiotoxin (3 microM), but not apamin (1 microM) or glibenclamide (0.1 microM), reversed the inhibition by VIP (10 nM) of cholinergic neural secretion. 4. Both endogenous VIP (by use of the VIP antibody; 1:500 dilution) and exogenous VIP (0.1 microM), the latter by 34%, inhibited ACh release from cholinergic nerve terminals and this suppression was completely reversed by iberiotoxin (0.1 microM). 5. We conclude that, in ferret trachea in vitro, endogenous VIP has dual activity whereby its small direct stimulatory action on mucus secretion is secondary to its marked regulation of cholinergic and tachykininergic neurogenic mucus secretion. Regulation is via inhibition of neurotransmitter release, consequent upon opening of BK(Ca) channels. In the context of neurogenic mucus secretion, we propose that VIP joins NO as a neurotransmitter of i-NANC nerves in ferret trachea.

Acetylcholine↗
PubMed1999

Effect of vasoactive intestinal peptide (VIP)-related peptides on cholinergic neurogenic and direct mucus secretion in ferret trachea in vitro.

1 We investigated whether vasoactive intestinal peptide (VIP) and its related peptides, pituitary adenylate cyclase activating peptide (PACAP) and secretin, regulate cholinergic neural mucus secretion in ferret trachea in vitro, using 35SO4 as a mucus marker. We also studied the interaction between VIP and secretin on cholinergic mucus output. 2 VIP (1 and 10 microM) increased secretion, whereas neither PACAP1 - 27, PACAP1 - 38 nor secretin (up to 10 microM) increased mucus output. In contrast, VIP, PACAP1 - 27 and PACAP1 - 38 concentration-dependently inhibited cholinergic neural secretion, with an order of potency of VIP>PACAP 1 - 38>PACAP1 - 27. Neither PACAP1 - 27 nor PACAP1 - 38 altered the secretion induced by acetylcholine (ACh). 3 Secretin increased cholinergic neural secretion with a maximal increase of 190% at 1 microM. This potentiation was blocked by VIP or atropine. Similarly, secretin (1 microM) potentiated VIP (1 microM)-induced mucus output by 160%. Secretin did not alter exogenous ACh-induced secretion. VIP vs secretin competition curves suggested these two peptides were competing reversibly for the same receptor. 4 We conclude that, in ferret trachea in vitro, VIP and PACAPs inhibit cholinergic neural secretion via pre-junctional modulation of cholinergic neurotransmission. VIP and secretin compete for the same receptor, possibly a VIP1 receptor, at which secretin may be a receptor antagonist.

Acetylcholine↗
PubMed1999

Function and sequence analyses of tumor suppressor gene p53 of CHO.K1 cells.

The tumor suppressor gene p53 plays an important role in guarding genomic integrity. When induced in response to environmental results, the gene product of p53 functions as a transcription factor to transactivate genes involved in arresting the cell cycle and as a facilitator of DNA repair. In contrast, the status of p53 in Chinese hamster ovary (CHO) cells, commonly used as a model system for various studies including those involving the cell cycle and transformation, remains an enigma. In this study, the function and sequence of p53 in CHO.K1 cells were investigated. The level of p53 proteins was elevated on ultraviolet (UV) irradiation of the cells, and the proteins formed specific complexes as probed with DNA containing p53-binding sequences. Its activities toward responsive promoters were inducible by UV in a dose-dependent manner. Although p53 in CHO.K1 contained a single missense mutation at codon 211, the mutation apparently had no effect on the functional properties of the protein. The CHO.K1 cells on X-ray irradiation failed to arrest at G1 phase even when the cells were transfected with a wildtype human p53 gene, indicating that the failure probably was not caused by dysfunction of its p53, but by some other mechanism. This result is consistent with the finding that p21(Waf1/Cip1) is undetectable in UV-treated CHO.K1 cells, whereas Gadd45 is induced by UV light in the cells.

3T3 Cells↗
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

A comparison among nalbuphine, meperidine, and placebo for treating postanesthetic shivering.

UNLABELLED: Postanesthetic shivering (PS) is distressing for patients and may induce a variety of complications. In this prospective, double-blinded, randomized study, we evaluated the value of nalbuphine, compared with meperidine and saline, for treating PS. Ninety adult patients were included in the study. Group 1 (n = 30) received i.v. nalbuphine 0.08 mg/kg, Group 2 (n = 30) received i.v. meperidine 0.4 mg/kg, and Group 3 (n = 30) received i.v. saline. Treatment that stopped shivering was considered to have been successful. The results demonstrated that, 5 min after treatment, both nalbuphine and meperidine provided a rapid and potent anti-shivering effect on PS, with high response rates of 80% and 83%, compared with those of saline (0%) (P < 0.01). Thirty minutes after injection, the response rates of nalbuphine and meperidine were 90% and 93%, respectively, compared with 17% in the saline group (P < 0.01). The differences between nalbuphine and meperidine were not significant. We conclude that nalbuphine may be an alternative to meperidine for treating PS. IMPLICATIONS: We evaluated nalbuphine versus meperidine and saline for treating postanesthetic shivering. Our results demonstrate that both nalbuphine and meperidine provide a similar rapid and potent anti-shivering effect. Nalbuphine may be an alternative to meperidine for treating postanesthetic shivering.

Adult↗
PubMed1999

The prophylactic effect of dexamethasone on postoperative nausea and vomiting in women undergoing thyroidectomy: a comparison of droperidol with saline.

UNLABELLED: The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in women undergoing thyroidectomy. Droperidol and saline served as controls. One hundred twenty women (n = 40 in each of three groups) undergoing thyroidectomy under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study. Immediately before the induction of anesthesia, Group 1 received IV dexamethasone 10 mg, whereas Groups 2 and 3 received IV droperidol 1.25 mg and saline, respectively. We found that both dexamethasone and droperidol significantly decreased the total incidence of PONV compared with saline, with an incidence of 32%, 35%, and 76%, respectively (P<0.01; Group 1 versus Group 3, Group 2 versus Group 3). Patients who received droperidol, however, reported a higher intensity of sore throat and a more frequent incidence of restlessness than those who received dexamethasone. We conclude that, although both dexamethasone and droperidol are effective as prophylactic antiemetics in women undergoing thyroidectomy, droperidol produces more side effects. IMPLICATIONS: We compared the prophylactic administration of dexamethasone to prevent nausea and vomiting with droperidol and saline in women undergoing thyroidectomy. Both dexamethasone and droperidol significantly reduced postoperative nausea and vomiting, but droperidol produced more side effects, which suggests that dexamethasone is a useful treatment in these patients.

Adult↗
PubMed1999

Comparison of a nonradiometric liquid-medium method (MB REDOX) with the BACTEC system for growth and identification of mycobacteria in clinical specimens.

Early identification of tuberculosis in the clinical setting is of great importance in order for specific therapy to be swiftly initiated. MB REDOX (Heipha Diagnostika), a growth-based medium without radioactive materials, was evaluated and was compared to the BACTEC system for detection of mycobacteria, including the Mycobacterium tuberculosis complex and atypical mycobacteria. MB REDOX consists of a Kirchner medium enriched with growth-promoting additives, antibiotic compounds, and a redox indicator which can be monitored to detect growth of mycobacteria with the naked eye. MB REDOX only detects growth and cannot differentiate the M. tuberculosis complex (M. tuberculosis, M. bovis, and M. africanum) from other species of Mycobacterium. Therefore, PCR-restriction fragment length polymorphism analysis (PRA) was used in this investigation to identify to the species level organisms showing positive growth with MB REDOX. Our data demonstrate the usefulness of MB REDOX for the detection of mycobacteria in clinical specimens. The rate of detection of M. tuberculosis complex with MB REDOX (84. 3%) was higher than that with the BACTEC system (68.6%). When combined with PRA for species identification, MB REDOX is easy to perform and is suited to most clinical laboratory settings for the detection and identification of mycobacteria.

Bacteriological Techniques↗
PubMed1999

Presentation of autoantibody to proliferating cell nuclear antigen in patients with chronic hepatitis B and C virus infection.

OBJECTIVES: To study the association of antibodies to proliferating cell nuclear antigen (PCNA) in patients with chronic hepatitis B (HBV) and C (HCV) virus infection. METHODS: Sera from 243 patients with chronic HBV infection; 379 patients with chronic HCV infection; 80 patients with systemic lupus erythematosus (SLE); 28 patients with rheumatoid arthritis; 15 patients with Sjogren's syndrome; eight with polymyositis; eight with primary biliary cirrhosis; and 33 healthy control subjects were tested for the presentation of anti-PCNA antibodies by enzyme linked immunosorbent assay (ELISA) and immunoblotting using recombinant PCNA as antigen. The distribution of immunoglobulin isotypes of anti-PCNA antibody was measured by ELISA assay. RESULTS: By ELISA, anti-PCNA antibodies were detected in 30 (12.3%) patients with chronic HBV infection, 71 (18.7%) patients with chronic HCV infection, and five (6.3%) patients with SLE. The inhibition of binding with these sera by purified PCNA was shown to exceed 71%. By immunoblotting, the frequency of anti-PCNA in patients with chronic HBV and HCV infection was 17 of 243 (7%) and 41 of 379 (11%), respectively. Absorption studies on indirect immunofluorescence showed the typical nuclear speckled staining pattern by anti-PCNA sera was abolished by preincubation of sera with PCNA. Anti-PCNA antibody was not detected in sera from patients with autoimmune diseases except SLE. Anti-PCNA antibodies in patients with chronic HBV and HCV infection were predominantly IgG. CONCLUSION: These data suggest that anti-PCNA antibody are also present in patients with chronic HBV and HCV infection. Anti-PCNA antibody may not be specific for SLE.

Animals↗
PubMed1999

Development of a coronary artery aneurysm three months after stent implantation: a case report.

Coronary artery stents have been used widely to prevent acute closure as a bailout procedure, or to decrease restenosis after balloon angioplasty. Stent use has increased substantially in recent years due to the ease and simplicity with which stents provide a predictable angiographic result. However, few data exist on the long-term safety of stents. This case report describes a 63-year-old male patient who developed intimal dissection after balloon angioplasty and who underwent coronary stent placement of a sheathed stent (half Palmaz-Schatz stent, 3.5 mm in diameter and 7 mm in length) as a bailout procedure. Postdilatation with a 3.5-mm balloon was performed at the maximum pressure of 14 atmospheres with a satisfactory angiographic result. However, an aneurysmal dilatation at the stent site was noted three months later. High-pressure stent use without immediately visible vascular dissection by angiography may not be effective for prevention of coronary aneurysm development in a case such as this. Aneurysmal dilatation may be a late complication in cases of coronary artery stent placement.

Angioplasty↗
PubMed1999

Line probe assay for rapid detection of mutations in the rpoB gene of Mycobacterium tuberculosis.

Detection of mutations in the rpoB gene of Mycobacterium tuberculosis has been reported to be an accurate predictor of rifampin resistance. DNA sequence analysis and screening methods such as single-strand conformation polymorphism analysis and dideoxy fingerprinting are labor-intensive, expensive, or yield results that may prove difficult to interpret. We evaluated the accuracy of a commercial line probe assay for rapid identification and characterization of mutations in the rpoB gene in 72 isolates of M. tuberculosis, including 50 rifampin-resistant and 22 rifampin-susceptible strains. Ten distinct rpoB mutations were identified. Concordances with automated sequencing results and phenotypic rifampin susceptibility testing results were 99% and 93%, respectively. The results demonstrate the line probe assay to be a rapid (as short as 1 day) and informative tool for the early detection and characterization of rpoB mutations associated with rifampin resistance in a clinical laboratory setting.

Antibiotics, Antitubercular↗
PubMed1999

Once daily isepamicin treatment in complicated urinary tract infections.

Isepamicin is a new aminoglycoside, derived from gentamicin B, which is more stable than other aminoglycosides against inactivating enzymes, and is less nephrotoxic. We evaluated the efficacy and safety of a once daily isepamicin in the treatment of complicated urinary tract infections (UTIs), as compared with amikacin. During the period May, 1997, to January, 1998, a total of 52 patients with similar demographic and baseline characteristics were enrolled into a prospective, randomized, open-label, single-center trial at the Veterans General Hospital-Kaohsiung. Eleven patients were excluded for protocol violation. The remaining 41 patients were included in the efficacy analysis. Study subjects included 16 men and 25 women, with a mean age of 57.9 (range 18-95) years. Clinical improvement was noted in 100% of patients in both the isepamicin and amikacin group. No statistically significant difference was observed between the 2 groups in regard to the rapidity of defervescence, relief of dysuria and urinary frequency, and clearance of bacteriuria and pyuria. Bacteriological cure rates were 89.4% for the isepamicin group and 100% for the amikacin group. Fifteen of 25 subjects who received isepamicin and 16 of 27 subjects who received amikacin had an adverse effect, all of which were considered to be mild except for one in the amikacin group, who had an adverse event of moderate severity (vomiting). Seven (3 isepamicin and 4 amikacin) adverse events were considered probably or possibly related to the study drug, which included eosinophilia (2 isepamicin), liver function impairment (1 isepamicin, 2 amikacin), renal function impairment (1 amikacin) and flushed face (1 amikacin). However, none of the patients had a life-threatening or severe adverse event that required discontinuation of the drug. These results show that once daily administration of isepamicin is as effective and safe as amikacin in treatment of complicated UTIs.

Adolescent↗
PubMed1998

Serum responsiveness of the rat PCNA promoter involves the proximal ATF and AP-1 sites.

We have previously shown that the rat PCNA (proliferating cell nuclear antigen) gene promoter is responsive to serum stimulation. In this study, the sequence of the promoter responsive to serum stimulation has been localized in the region between nucleotides -70 and +125 relative to the transcription initiation site. This region contains an ATF site (nucleotides -51 to -44) and an AP-1 site (nucleotides -64 to -58). Mutation at either the ATF or the AP-1 site reduced the serum responsiveness of the promoter. In gel mobility shift assays, nuclear extracts from serum stimulated cells, compared to those from quiescent cells, exhibit an increasing binding activity toward a promoter related oligonucleotide (-70 to -42) which includes the ATF site and the AP-1 site. Formation of the DNA:protein complexes requires the simultaneous involvement of ATF and AP-1 sites as either element can abrogate the complexes in the competition experiment. Both the distance and sequence are essential to complex formation. Moreover, ATF-1 but not ATF-2 (or CREB) has been identified as a major component of the complexes in the antibody supershift or interference experiment. The results of this study suggest that ATF-1 in association with other factors is involved in regulating the serum stimulation of the rat PCNA promoter activity via the proximal ATF and AP-1 sites.

Activating Transcription Factors↗
PubMed1998

Mounting and brief noncontact exposure of males to receptive females facilitate reflexive erection in rats, even after hypogastric nerve section.

In three experiments, reflexive erection in male rats was facilitated by housing the males for 2 min with inaccessible sexually receptive females. In Experiment 1, males were sexually naive or experienced and received two reflexive erection tests, 1 week apart, immediately after the males were exposed to receptive females, to unreceptive females, or to no females (n = 8 per group). In both tests, experienced males exposed to estrous females had the shortest reflexive erection latencies; in Test 1 the differences among groups were of borderline significance (p = 0.057), but in Test 2 the differences among groups were highly reliable (p<0.01). Further analysis indicated that only experienced males exposed to receptive females were significantly different from other groups. In Experiment 2, sexually experienced males (n = 11) received four reflexive erection tests: after being with no female, and 0, 5, or 10 min after exposure to estrous females. As the interval between exposure and test increased, the males had progressively shorter erection latencies (p<0.01) and more intense glans erections (p<0.03). Experiments 1 and 2 may be viewed as demonstrating the psychogenic facilitation of reflexive erections. In Experiment 3, males underwent sham surgery (sham, n = 10) or bilateral transection of the hypogastric nerves (HgNx, n = 10), which are conventionally viewed as mediating psychogenic erection. After males mounted a receptive female for 5 min without intromission or had 2 min of non-contact exposure to receptive females, the males had shorter erection latencies (p<0.001) and more erections (p<0.02). These facilitative effects of pretest stimulation were unaffected by HgN transection. During copulation tests, HgNx males had longer ejaculation latencies (p<0.05) and lower intromission ratios (p<0.05), possible signs of impaired erectile function. However, in Experiment 4, other males were tested twice for reflexive erection and copulation after sham (n = 8) or HgNx (n = 9) surgery, and there were no significant effects of surgery on reflexive erection or copulatory behavior. Collectively, these experiments indicate (a) that brief noncontact exposure of sexually experienced males to estrous females facilitates reflexive erection, (b) that this facilitation increases for at least 10 min after the females are removed, and (c) that the hypogastric nerves do not mediate these facilitative effects. The evidence for a role for the HgN in copulation was inconclusive.

Animals↗