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Biomedical subjects

H C Lin

Publications and source records attributed to H C Lin.

At least 325 records · Page 18Linked to original sources
PubMed1993

Immobilization and anesthesia of two hand-reared zebras.

This report describes our experiences with 2 drug combinations that were used safely and effectively to immobilize and anesthetize 2 hand-reared zebras. Zebras were sedated with xylazine hydrochloride or detomidine. The latter is more potent and of more use in healthy, vigorous animals. Anesthesia was induced with thiamylal/guaifenesin or tiletamine/zolazepam. The latter is more convenient because a quick, simple IV injection will preclude the necessity for physical restraint required to administer a large volume of guaifenesin/thiobarbiturate combination. Tracheal intubation was easily accomplished with either induction regimen, and inhalation anesthetic was used for longer periods of anesthesia.

Anesthesia↗
PubMed1993

Prevalence, infectivity, and risk factor analysis of hepatitis C virus infection in prostitutes.

A population of 622 prostitutes in Taiwan was tested for antibodies to the hepatitis C virus (anti-HCV) using a synthetic peptide assay composed of representative determinants from capsid and nonstructural (NS) viral proteins. Seventy-four (12%) were positive and the remaining 548 (88%) were negative. Seventy-nine samples were retested by a second-generation anti-HCV assay composed of recombinant capsid and NS proteins of HCV. Both assays had a nearly perfect agreement (Kappa value = 0.91). Of the positive cases, 31% were positive for reactivity to capsid only. Most (60/74, 81%) of the cases positive for synthetic peptide assay were HCV RNA positive, indicating potential infectivity. On the basis of the results of synthetic peptide assay, univariate analysis showed that history of paid sex for longer than 6 months, blood transfusion, acupuncture, intravenous drug abuse, and age over 20 years were significant risk factors of HCV infection (P < 0.01). Elevated alanine aminotransferase levels (> 40 U/L) were positively associated with anti-HCV, while the presence of serum hepatitis B surface antigen was a negatively associated factor. Multivariate analysis revealed that history of paid sex for longer than 6 months and blood transfusion were positively associated with anti-HCV (P < 0.001). The latter only accounted for less than one fifth of the HCV-infected prostitutes. This study indicates strongly that sexual transmission is an important route for HCV infection in prostitutes. This risk group may spread HCV to other populations as a sexually transmitted disease.

Adolescent↗
PubMed1993

The effect of salinity on the acute toxicity of cadmium to the tropical, estuarine, hermaphroditic fish, Rivulus marmoratus: a comparison of Cd, Cu, and Zn tolerance with Fundulus heteroclitus.

The mangrove-dwelling fish, Rivulus marmoratus, is the only vertebrate that is a synchronous, internally self-fertilizing hermaphrodite. This unique reproductive mode yields offspring with little genetic variation, which offers significant advantages for the use of this species in bioassays. We conducted acute (96 h) LC50 tests of Cd toxicity under four different water chemistry conditions, representing fresh water (low [Ca+Mg] and low [Na+K]), 14 ppt sea water simulated with Cl salts (high [Ca+Mg] and high [Na+K]) and two artificial conditions (high [Ca+Mg], low [Na+K] and low [Ca+Mg], high [Na+K]). Two replicates were conducted at different times for each of the four treatments and the results were very reproducible. The mean LC50's as mg total Cd/L were 2.96 (fresh water), 21.12 (high [Ca+Mg], high [Na+K]), 17.86 (high [Ca+Mg], low [Na+K]) and 12.67 (low [Ca+Mg], high [Na+K]). An additional test in 14 ppt sea water (made up from Instant Ocean salts) yielded a 96h LC50 of 24.48 mg Cd/L, and was thus similar to the high [Ca+Mg]-high [Na+K] treatment, despite some differences in anion and cation concentrations. The degree to which [Ca+Mg], [Na+K] and [Cl] interact to determine Cd toxicity is still unclear, although the role of [Cl] is likely to be equal to or greater than that of [Ca+Mg]. When all solutes are high, it is likely that the formation of a Cd complex with Cl (248 mM) leads to the observed reduction in Cd toxicity in comparison with hard fresh water, not the increased divalent [Ca+Mg] levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Changes of sex hormone levels in patients with hepatitis B virus-related postnecrotic cirrhosis: relationship to the severity of portal hypertension.

The effect of portal hypertension on plasma sex steroid levels was studied in 49 patients with hepatitis B virus-related postnecrotic cirrhosis. In accordance with the Child-Pugh classification, 18 patients were classified as grade A, 15 grade B and 16 grade C. At the same time, 25 males who were admitted for physical check-up served as normal controls. Serum testosterone levels decreased (3.31 +/- 2.03 vs. 5.65 +/- 0.13 ng/ml) and estrone levels increased (0.16 +/- 0.08 vs. 0.09 +/- 0.02 ng/ml) significantly in patients with cirrhosis compared to the levels obtained in the controls. Moreover, these changes were associated with an increased severity of cirrhosis (P < 0.05 when severity increased from grade A to C). Hemodynamic values regarding hepatic venous pressure gradient and cardiac output demonstrated significant differences in patients from grade A to C, but the correlation between these two parameters was poor (r = 0.3242). The hepatic venous pressure gradient, the only direct measurement of portal hypertension, did not correlate with any of the measured hormone levels in patients with cirrhosis. There was, however, a highly significant negative correlation between cardiac output and testosterone levels (r = -0.8754, P < 0.01) and a positive correlation between cardiac output and estrone levels (r = 0.7522, P < 0.05) in grade C patients. On the basis of these results, we concluded that gonadal dysfunction is a common finding in patients with hepatitis B related postnecrotic cirrhosis, especially in those with decompensated liver function. The relationship between cardiac output and severity of liver disease suggests that the degree of portosystemic shunting probably increases as liver disease worsens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hepatic hemodynamic features in patients with esophageal or gastric varices.

One hundred and fifty cirrhotic patients with or without esophageal varices and/or gastric varices were investigated by endoscopy and hepatic venous catheterization to evaluate differences in the degree of portal hypertension, main portal venous diameter and frequency of portal systemic encephalopathy. Hemodynamic values were correlated with varices size as assessed by endoscopy. Patients with large gastric varices had wedged hepatic venous pressures and hepatic venous pressure gradients which were lower than patients with esophageal varices only, but similar to patients without varices. In addition, in patients with large gastric varices, a decrease in the diameter of the main portal vein and an increase in the incidence of chronic portal systemic encephalopathy were noted. Our results implied that patients with large gastric varices presented different hemodynamic features including the degree of portal hypertension and the incidence of portal systemic encephalopathy from patients with esophageal varices only.

Aged↗
PubMed1993

Effects of reserpine administration in two models of portal hypertension in rats.

The effects of reserpine were investigated in two models of portal hypertension in rats. Twenty-four hours after 1 mg/kg of reserpine was administered intraperitoneally to normal and portal vein stenosed rats, the cardiac index, mean arterial pressure, heart rate, and portal pressure were significantly decreased compared with normal and portal vein stenosed rats receiving placebo. In addition, the portal tributary blood flow was significantly decreased in portal vein stenosed rats receiving reserpine, but was unchanged in normal rats. In cirrhotic rats receiving a single dose of reserpine, 0.1 mg/kg intraperitoneally for 24 h, there were significant decreases in cardiac index, mean arterial pressure and heart rate compared with cirrhotic rats receiving placebo, while the portal pressure and portal tributary blood flow followed a decreasing trend after reserpine administration. The degree of hemodynamic change was similar in the groups of rats receiving reserpine, even though cirrhotic rats received lower doses than either normal or portal vein stenosed rats. This study suggests enhanced sympathetic nervous activity observed in cirrhotic rats.

Animals↗
PubMed1993

Functional domains of the penicillinase repressor of Bacillus licheniformis.

The penicillinase repressor (PENI) negatively regulates expression of the penicillinase gene (penP) in Bacillus licheniformis by binding to its operators located within the promoter region of penP.penI codes for a protein with 128 amino acids. Filter-binding analyses suggest that the active form of the repressor is a dimer. Genetic analyses of PENI derivatives showed that the repressor carrying either a 6-amino-acid deletion near the N terminus or a 14-amino-acid deletion at the C terminus was functionally inactive in vivo. A repressor derivative carrying a 6-amino-acid deletion within its N-terminal region was extensively purified and used in DNA footprinting and subunit cross-linking analyses. The results of these studies showed that the repressor derivative had lost its ability to bind operator specifically even though it could dimerize effectively. In similar studies, we demonstrated that an N-terminal portion of PENI with a molecular mass of 10 kDa derived by digestion with papain was able to bind operator specifically but with reduced affinity and had completely lost its ability to dimerize. These data suggest that the repressor has two functional and separable domains. The amino-terminal domain of the repressor is responsible for operator recognition, and the carboxyl-terminal domain is involved in subunit dimerization.

Amino Acid Sequence↗
PubMed1993

Nutrient feedback inhibition of gastric emptying plays a larger role than osmotically dependent duodenal resistance.

The slowing of gastric emptying by hyperosmolar solutions has been postulated to result from the triggering of duodenal osmoreceptor feedback on the stomach. We tested the idea that the inhibition of gastric emptying by a hyperosmolar solution depended on the duodenal resistance and the triggering of nutrient-specific feedback by tracking gastric emptying of 300 and 1,200 mosmol/kgH2O test solutions in 12 dogs in which duodenal resistance was either removed (by temporarily diverting chyme from uncorked duodenal fistula) or preserved (by keeping duodenal fistula corked). Mannitol was used to test osmolality alone, and glucose was used to examine the combined effects of osmolality and nutrient-specific inhibitory feedback. We found that: 1) the slowing effect of hyperosmolality was more marked with the duodenal resistance preserved (P < 0.05; analysis of variance), 2) the slowing effect of glucose was greater than that of mannitol for all conditions (P = 0.01; analysis of variance), and 3) the inhibitory effect of mannitol was localized to the duodenum. We conclude that inhibition of gastric emptying by hyperosmolar mannitol depended primarily on duodenal resistance, while the inhibitory effect of hyperosmolar glucose depended on nutrient-specific feedback on the stomach more than duodenal resistance.

Animal Nutritional Physiological Phenomena↗
PubMed1993

Hemostasis in cows with endotoxin-induced mastitis.

Hemostasis was evaluated in cows with experimentally induced endotoxemia and mastitis, caused by intramammary infusion of endotoxin (1 mg) derived from Escherichia coli. Hemostatic tests included prothrombin time; activated partial thromboplastin time; thrombin time; fibrinogen, fibrin(ogen) degradation products, and platelet concentrations; and antithrombin-III and plasminogen activities. Significant alterations were observed in the mean values of most analytes (prothrombin time was increased; thrombin time was increased with subsequent decrease; activated partial thromboplastin time, fibrinogen concentration, plasminogen activity, and platelet concentration were decreased; and antithrombin-III activity and fibrin(ogen) degradation products concentration were unchanged) at 1 or more postchallenge sample collection times (3, 12, or 24 hours) after endotoxin administration, compared with mean values obtained from samples prior to endotoxin administration. These data indicated activation of hemostatic mechanisms, initiated either directly by endotoxin or by inflammatory mediators released or produced in response to endotoxin infusion.

Animals↗
PubMed1993

Influence of anesthetic regimens on the perioperative catecholamine response associated with onychectomy in cats.

Plasma catecholamine concentrations in response to onychectomy were examined in 27 cats receiving different anesthetic regimens. Each cat was anesthetized with a dissociative-tranquilizer combination, and onychectomy was performed on 1 forefoot. One week later, each cat was anesthetized with the same dissociative-tranquilizer combination plus either butorphanol or oxymorphone, and onychectomy was performed on the other forefoot. Four treatment groups were studied: tiletamine-zolazepam and tiletamine-zolazepam-butorphanol combinations were administered to group-1 cats, ketamine-acepromazine and ketamine-acepromazine-butorphanol combinations were administered to group-2 cats, tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone combinations were administered to group-3 cats, and ketamine-acepromazine and ketamine-acepromazine-oxymorphone combinations were administered to group-4 cats. All drug combinations were administered IM. Central venous blood samples were drawn for catecholamine analysis after injection of drug(s), after onychectomy, and 1, 2, and 4 hours after injection. Tiletamine-zolazepam alone or tiletamine-zolazepam-butorphanol prevented epinephrine release for 2 hours after injection of drug(s). Norepinephrine concentration increased significantly (P < 0.05) from baseline after onychectomy for tiletamine-zolazepam-butorphanol and at 4 hours for tiletamine-zolazepam and tiletamine-zolazepam-butorphanol. After onychectomy, there was no difference in epinephrine values between tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone. Ketamine-acepromazine prevented increases in norepinephrine and epinephrine concentrations for up to 2 hours after surgery. Addition of butorphanol to ketamine-acepromazine decreased norepinephrine values immediately after onychectomy. Addition of oxymorphone to ketamine-acepromazine resulted in lower epinephrine values 4 hours after surgery.

Anesthesia, General↗
PubMed1993

Effects of anesthesia induced and maintained by continuous intravenous administration of guaifenesin, ketamine, and xylazine in spontaneously breathing sheep.

Anesthesia was induced and maintained in 6 Suffolk wethers by continuous i.v. infusion of guaifenesin (50 mg/ml), ketamine (1 mg/ml), and xylazine (0.1 mg/ml) in 5% dextrose in water (triple drip) to assess the anesthetic and cardiopulmonary effects. All sheep were positioned in right lateral recumbency. Dosages of triple drip used for induction and maintenance of anesthesia were 1.2 +/- 0.02 ml/kg and 2.6 ml/kg/h, respectively. Lack of gross purposeful movement of sheep to electrical stimulation indicated that analgesia and muscular relaxation induced by triple trip were adequate for surgical procedures. Heart rates and arterial blood pressure remained unchanged from baseline values during a 1-hour period of anesthesia. Arterial blood pressures were measured indirectly, using an inflation cuff placed over the metatarsal artery at the heart level. Significant decrease in arterial partial pressure of O2 (PaO2), coupled with an increase in arterial partial pressure of CO2 (PaCO2), from baseline values was observed throughout the course of the study. Decrease in PaO2 was observed concomitantly with significant (P < 0.05) increase in respiration rate. Changes in arterial blood gas tensions observed in this study were attributed to respiratory depressant effect induced by anesthetic drugs and right-to-left shunting, perfusion/ventilation mismatch, or both caused by right lateral recumbency. Administration of 100% O2 via the endotracheal tube reduced the magnitude of the decrease in PaO2. All sheep recovered smoothly and stood within 96.3 +/- 48.9 minutes after termination of triple drip administration.

Anesthesia, Intravenous↗
PubMed1993

[Stress fracture of the ribs in amateur golfers diagnosed by Tc-99m MDP scintigraphy].

Golf has become a popular sport in Taiwan recently. Some amateur golfers suffer from back or chest pain, and a few of them have stress fractures of the ribs. Six amateur golfers suffering from back pain or chest pain, all male and right-handed players, aged from 28 to 39, were included in our study. The initial chest roentgenograms, including special views focusing on ribs, were all negative. Tc-99m MDP bone scan confirmed the diagnosis of stress fractures of the ribs. The intervals between playing golf and time of diagnosis were from 1 month to 5 months. In five cases, fracture sites in the left side were prominently located in the posterior aspect, a condition which may result from traction of the serratus anterior. Three cases with fracture sites in the right side had fractures prominently located in the lateral aspect, which may result from the repercussive force produced by the clubhead hitting the ground. Tc-99m MDP bone scan, with its high sensitivity, is useful in establishing the diagnosis of stress fracture.

Adult↗
PubMed1993

Telazol and xylazine anesthesia in sheep.

The analgesic and anesthetic effects of Telazol (13.2 mg/kg, IV) and xylazine (0.11 mg/kg, IV)-Telazol (13.2 mg/kg, IV) were evaluated in 6 sheep. Anesthesia was characterized by muscle relaxation and profound analgesia with both regimens, muscle relaxation appeared to be better in sheep receiving xylazine-Telazol. The duration of analgesia was significantly longer in sheep receiving xylazine-Telazol (101.7 +/- 26 minutes) than in sheep receiving Telazol alone (41.6 +/- 15 minutes). Changes in heart rate and respiration rate were transient with both regimens. Apnea occurred in 2 sheep immediately after xylazine-Telazol administration, requiring assisted ventilation, but both sheep resumed spontaneous breathing within 2 minutes. Arterial blood pressure decreased significantly at 45 and 60 minutes after xylazine-Telazol injection. Arousal to standing was smooth, but gradual with no significant difference between the two drug regimens. In conclusion, xylazine-Telazol combination produced better muscle relaxation and longer duration of anesthesia than Telazol alone. The adverse effects induced by xylazine-Telazol were similar to that of Telazol.

Analgesia↗
PubMed1992

Characterization of the Erwinia carotovora peh gene and its product polygalacturonase.

The peh gene, encoding polygalacturonase (Peh), was identified in Erwinia carotovora strain EC and cloned in Escherichia coli. Recombinant Peh (re-Peh) was purified from E. coli strain 706 containing peh on a recombinant plasmid. The activity of the re-Peh protein is optimal at pH 5.5. The N-terminal and internal amino acid (aa) sequences of re-Peh were determined and compared to the aa sequence deduced from the nucleotide (nt) sequence of the cloned peh. The re-Peh has no similarity, based on either the nt sequences or the deduced aa sequences, to pectate lyases from the same Er. carotovora strain or other organisms.

Amino Acid Sequence↗
PubMed1992

Annexin VI is required for budding of clathrin-coated pits.

Isolated plasma membranes attached to a solid substratum at 4 degrees C have numerous clathrin-coated pits. These pits initially are flat but become deeply invaginated after warming to 37 degrees C. The pits remain tethered to the membrane in this rounded condition unless supplied with ATP, Ca2+, and cytosol. We now show that when cytosol is treated to remove the Ca(2+)-dependent, phospholipid-binding protein annexin VI, coated pit budding no longer takes place. Addition of purified annexin VI back to the annexin VI-depleted cytosol restores budding activity to normal. Purified annexin VI alone shows only a modest budding activity, suggesting that the cytosol contains a factor(s) in addition to annexin VI that is required for full activity. Cytosol-dependent activation of annexin VI requires both ATP and Ca2+. Annexin VI appears to be not only an active component in the detachment of coated pits from the membrane but also a site for regulating the formation of coated vesicles.

Adenosine Triphosphate↗
PubMed1992

Hemodynamic effects of calibrated stenosis of the superior mesenteric artery in conscious rats with portal vein stenosis.

Because superior mesenteric arterial blood flow is increased in portal hypertension and plays a role in elevated portal pressure, mechanical reduction of artery diameter should induce decreases in portal pressure and superior mesenteric arterial blood flow. In this study, calibrated superior mesenteric artery stenosis (induced with a 22-gauge needle) was performed in rats simultaneously with portal vein stenosis or 2 wk after creation of portal vein stenosis. Hemodynamic studies were performed 3 wk after induction of portal vein stenosis in conscious, unrestrained rats. At that time, neither weight loss nor digestive tract alterations were observed in rats with arterial stenosis. In neither group of rats with arterial stenosis was portal tributary blood flow significantly different from that of normal rats; nor was it significantly lower than in rats with portal vein stenosis without arterial stenosis. In both groups of rats with arterial stenosis, portal pressure was significantly lower (12.1 +/- 1.6 mm Hg and 12.5 +/- 1.8 mm Hg, respectively) than in rats subjected to portal vein stenosis (15.4 +/- 1.5 mm Hg) but significantly higher than in controls (7.2 +/- 1.0 mm Hg). In rats with arterial stenosis, cardiac index was also significantly lower than that in rats with portal vein stenosis but higher than that in controls. In conclusion, this study shows that both early and late superior mesenteric artery stenosis significantly reduce the degree of portal hypertension and the hyperkinetic state of rats with extrahepatic portal hypertension. Thus we can speculate that superior mesenteric artery stenosis might provide a new therapeutic approach for portal hypertension.

Analysis of Variance↗