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Biomedical subjects

C C Lo

Publications and source records attributed to C C Lo.

At least 19 recordsLinked to original sources
PubMed2005

Adsorption of ethyl violet dye in aqueous solution by regenerated spent bleaching earth.

The adsorption of basic dye (i.e., ethyl violet or basic violet 4) from aqueous solution onto the regenerated spent bleaching earth (RSBE) was carried out by varying the process parameters such as initial concentration, pH, and temperature. As analytical comparisons, activated bleaching earth (ABE) was also used as adsorbent for the adsorption of the basic dye at various initial concentrations. The experimental results showed that the adsorption process can be well described with the pseudo-second-order reaction model and less fitted by the intra-particle diffusion model. The kinetic parameters of both models obtained in the present work are in line with pore properties of the two adsorbents. According to the equilibrium adsorption capacity from the fitting of pseudo-second-order reaction model, it was further found that the both models of Langmuir and Freundlich appeared to fit well the isotherm data. In addition, the thermodynamic parameters were evaluated based on the pseudo-second-order rate constants, showing that the adsorption of ethyl violet onto the RSBE is endothermic in nature.

Adsorption↗
PubMed2005

Removal of herbicide paraquat from an aqueous solution by adsorption onto spent and treated diatomaceous earth.

A spent diatomaceous earth from the beer brewery has been tentatively activated by sodium hydroxide at about 100 degrees C. The resulting product was used as a novel adsorbent for the adsorption of herbicide paraquat from an aqueous solution in a continuously stirred adsorber and batch flasks, respectively. The results showed that the adsorption process could be well described by the pseudo-second-order reaction model. From the view of the negatively charged surface of diatomaceous earth and cationic property of paraquat, the results were also reasonable to be explained by physical adsorption in the ion-exchange process under the effects of pH and temperature. Further, it was found that the Freundlich model appeared to fit the isotherm data better than the Langmuir model.

Adsorption↗
PubMed2004

Endoscopic balloon dilatation is a safe method in the management of common bile duct stones.

BACKGROUNDS AND AIMS: Endoscopic sphincterotomy is a widely accepted treatment for patients with common bile duct stones. Despite improvement in this technique, endoscopic sphincterotomy is still associated with some biliary complications. Endoscopic balloon dilatation is a less traumatic and sphincter preserving method for removal of common bile duct stones. However, the results of controlled studies in comparison with these two methods are contradictory. The aim of this study is to compare the safety and efficacy of endoscopic balloon dilatation and endoscopic sphincterotomy in Chinese patients. PATIENTS AND METHODS: A total of 104 patients with common bile duct stones on endoscopic retrograde cholangiopancreatography were enrolled. They were randomly assigned to endoscopic balloon dilatation or endoscopic sphincterotomy. Endoscopic balloon dilatation was performed by using a balloon dilator to dilate the sphincter for 5 min. The common bile duct stones were then removed by a Dormia basket after endoscopic balloon dilatation or endoscopic sphincterotomy. Mechanical lithotripsy was performed if the stones were difficult to remove by Dormia basket. After discharge, patients were regularly followed up for biliary complications. RESULTS: The successful bile duct stone clearance rate was 94.1% in endoscopic balloon dilatation group and 100% in endoscopic sphincterotomy group. Post-procedural significant haemorrhage was higher in endoscopic sphincterotomy group than in endoscopic balloon dilatation group (14/53 versus 1/48, P < 0.001). The bleeding patient from endoscopic balloon dilatation group was a case of uremia and bleeding occurred 48 h after endoscopic balloon dilatation. All the patients with post-procedural haemorrhage were controlled endoscopically. The post-procedural serum amylase level showed no significant difference in both groups and none of them developed clinical pancreatitis. After a mean 16 months follow-up, three patients (6.3%) in endoscopic balloon dilatation group and four patients (7.5%) in endoscopic sphincterotomy group developed recurrent common bile duct stones. The recurrent common bile duct stones were multiple and muddy in consistency. They were successfully removed endoscopically. CONCLUSION: Both endoscopic balloon dilatation and endoscopic sphincterotomy are safe and effective techniques for the treatment of common bile duct stones. Endoscopic balloon dilatation can be safely applied in patients with coagulopathy and does not increase the incidence of pancreatitis or bleeding.

Adult↗
PubMed2003

Endoscopic 13C-urea breath test for the diagnosis of Helicobacter pylori infection.

BACKGROUND: Endoscopic 13C-urea breath test may avoid contamination of oral urease and rapidly discriminate Helicobacter pylori-positive and Helicobacter pylori-negative patients. AIMS: To compare the accuracy of endoscopic 13C-urea breath test with conventional invasive methods in diagnosis of Helicobacter pylori infection. PATIENTS: One hundred patients who attended for routine upper gastrointestinal endoscopy were included. METHODS: 13C-urea was applied to the stomach through the working channel of endoscope at the end of endoscopic examination. Breath samples were collected before endoscopy and 2, 4, 6, 8, 10 min after consumption of 100 or 50 mg 13C-urea. Helicobacter pylori infection was defined as those with positive culture or positive results of both histology and CLO test. RESULTS: The accuracy of 100 mg endoscopic 13C-urea breath test was significantly higher than that of culture and CLO test (100% vs. 88% and 92%, p = 0.02 and 0.03, respectively). The accuracy of 50 mg endoscopic 13C-urea breath test was higher than that of histology and CLO test (98% vs. 90% and 96%, respectively), although the differences were not statistically significant. CONCLUSIONS: Endoscopic 13C-urea breath test has a higher accuracy compared with biopsy-based modalities. It may be a good choice to diagnose Helicobacter pylori infection if endoscopy is indicated for a dyspeptic patient.

Adult↗
PubMed2002

Effect of storage time and temperature on stallion sperm DNA and fertility.

We used the sperm chromatin structure assay (SCSA) to study the change in stallion sperm DNA susceptibility to denaturation after exposure of extended semen to three different storage temperatures (5, 20, or 37 degrees C) at 7, 20, 31, and 46 h. In addition, we compared the rates of sperm DNA denaturation in fertile and subfertile stallions. Among fertile stallions, spermatozoa stored at 20 and 37 degrees C showed a significant (P < 0.05) rise in the SCSA measures (Mean(alpha1), S.D.(alpha(t)), and percent cells outside the main population-COMP(alpha(t))) overtime, with the degree of rise being more dramatic at 37 degrees C. Over all stallions, samples stored at 5 degrees C showed no significant (P > 0.05) changes in the SCSA values measured over time, indicating maintenance of chromatin quality for up to 46 h. The COMP(alpha(t)) from stallions classified as subfertile showed an increased susceptibility to denaturation or decline in chromatin quality between 20 and 31 h when stored at 5 degrees C; however, spermatozoa from fertile stallions did not change during the time intervals analyzed. These data suggest that sperm DNA from some subfertile stallions may decline at a greater rate than spermatozoa from fertile stallions when exposed to similar storage conditions.

Animals↗
PubMed2001

Determination of tetracycline and streptomycin in mixed fungicide products by capillary zone electrophoresis.

A method of capillary zone electrophoresis (CZE) was used to determine tetracycline and streptomycin content in commercial agriculture products. The results indicated that this method was capable of analyzing the mixed fungicide in formulated products with instrument detection limit (IDL) of 0.50 microg/mL and a method detection limit (MDL) of 0.52 microg/mL for tetracycline, and IDL of 1.00 microg/mL and MDL of 1.22 microg/mL for streptomycin. Precision expressed by relative standard deviation (RSD) ranged from 1.44 to 4.37% of tetracycline and 1.00 to 4.20% of streptomycin. Recoveries were in the region of 98.2-102.5% for tetracycline and 95.3--103.0% for streptomycin. The low detection limit, the low RSD values, and the high percentage of recovery confirmed that the CZE technique is a sensitive and selective method. And the CZE method can analyze both tetracycline and streptomycin at the same time without complicated extraction and further derivative reaction.

Anti-Bacterial Agents↗
PubMed2001

Clinical significance of oral urease in diagnosis of Helicobacter pylori infection by [13C]urea breath test.

This study was performed to evaluate the effect of oral flora on [13C]urea breath test in detecting H. pylori infection and find an optimal method and timing for sample collection. Forty-five volunteers were included in this study. The [13C]urea breath test was performed using mouthwash, endoscopic administration, and conventional methods. According to the receiver-operating characteristic curves, the earliest optimal time for discriminating H. pylori-positive and H. pylori-negative patients was at 25 min with the mouthwash method with 78% sensitivity and 82% specificity, at 2 min with the endoscopic administration method with 100% sensitivity and 100% specificity, and at 6 min with the conventional method with 100% sensitivity and 95% specificity. The study shows a significant effect of oral urease on the results of the [13C]urea breath test. The timing of sampling collection can be shortened to 6 min with the conventional method or to 2 min through endoscopic administration.

Adult↗
PubMed2001

Eradication of Helicobacter pylori prevents ulcer development in patients with ulcer-like functional dyspepsia.

BACKGROUND: Although the eradication of Helicobacter pylori infection benefits patients with gastric or duodenal ulcers, the value of eradicating the infection in the patients with functional dyspepsia (FD) remains controversial. AIMS: To determine whether eradicating H. pylori can prevent the subsequent development of ulcers or relieve the symptoms of functional dyspepsia patients. METHODS: In a double-blind, placebo-controlled trial, 161 patients infected with H. pylori who had functional dyspepsia were randomly assigned to 7 days of treatment with a lansoprazole-based triple therapy or placebo and then followed for 1 year. The main outcome measures were the development of peptic ulcers and the resolution of symptoms. RESULTS: H. pylori was eradicated in 63 out of 81 patients (78%) in the treatment group and none of the 80 patients (0%) in the placebo group. During the follow-up period, two patients in the treatment group and six patients in the placebo group developed peptic ulcers at repeat endoscopy (2.5% vs. 7.5%; 95% CI: -12 to 2). The reduction in ulcer rates was statistically significant in the 'ulcer-like' sub-group (0% vs. 16.7%; 95% CI: -32 to -2), but not in the 'dysmotility-like' and 'unclassifiable' sub-groups. Regarding symptom response, the resolution rates of symptoms were similar between the treatment and placebo groups (58.0% vs. 55.0%, 95% CI: -12 to 18). Additionally, no significant differences existed in the symptom responses between the treatment and control arms in each of the dyspepsia sub-groups. CONCLUSIONS: Eradicating H. pylori can prevent the subsequent development of peptic ulcers in the patients with 'ulcer-like' functional dyspepsia. However, this approach does not significantly reduce the symptoms of functional dyspepsia patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Comparison of clinical, serological and histological findings between non-ulcer dyspepsia patients with and without Helicobacter pylori infection.

BACKGROUND AND AIMS: The role of Helicobacter pylori (H. pylori) infection in non-ulcer dyspepsia (NUD) remains controversial. This study investigates the clinical, serological and histological differences between patients with H. pylori-positive and -negative NUD. METHODS: One hundred and eighty consecutive patients with NUD were enrolled from January to December 1998. The severity of symptoms was evaluated by the Tucci's scoring system. The histological changes of gastric mucosa were assessed according to the Updated Sydney System, and a fasting blood sample was obtained to test the serum gastrin and pepsinogen I levels. RESULTS: The H. pylori-positive NUD patients were notably older than H. pylori-negative NUD patients (48.2 +/- 15.9 vs 39.8 +/- 15.7 years, P= 0.001). There were no differences in other clinical factors between the two NUD groups. The serum pepsinogen I levels were considerably higher in H. pylori-positive NUD patients than in H. pylori-negative NUD patients (78.9 +/- 42.2 vs 61.5 +/- 43.3 ng/mL, P<0.01). However, no significant differences in serum gastrin levels were discovered between the two groups. The antrum histological scores for chronic inflammation, acute inflammation, gland atrophy and lymphoid follicles were higher in H. pylori-positive NUD patients than in H. pylori-negative NUD patients (2.09 vs 1.01, P<0.001; 1.22 vs 0.36, P<0.001; 0.76 vs 0.36, P<0.01; 0.33 vs 0.13, P<0.01, respectively). CONCLUSIONS: The present study discovered marked differences in age, serum pepsinogen I levels, histological grades of acute inflammation, chronic inflammation, gland atrophy and lymphoid tissue formation between H. pylori-positive and H. pylori-negative NUD patients. Further investigation of the clinical prognosis of the two groups of patients is necessary.

Adult↗
PubMed2001

Sequential changes of gastric hyperplastic polyps following endoscopic ligation.

BACKGROUND: Endoscopic ligation has been extensively applied in the management of esophageal and gastric varices with or without bleeding. The varices are automatically eradicated through the use of ligation. However, whether avascular necrosis will occur in a gastrointestinal polyp when the base is ligated remains unclear. The aims of this pilot study were to investigate the sequential changes of gastric hyperplastic polyps following endoscopic detachable snare ligation and to determine the possibility of induction of avascular necrosis in these lesions following ligation. METHODS: Eleven patients with eighteen gastric hyperplastic polyps were treated with endoscopic detachable-snare ligation. The polyps were observed for 5 minutes and biopsies were then conducted. At 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcome of the strangulated polyps. RESULTS: After being strangulated by the detachable snares, a majority of the polyps immediately congested (94%), and then developed cyanotic change (89%) approximately 4 minutes later. Pathological examination revealed severe venous congestion in the lamina propria of the strangulated polyps. On follow-up endoscopy 2 weeks later, all the snares had dropped off, and avascular necrosis occurred in sixteen polyps (89%). All of the polyps with avascular necrosis were detected to have developed cyanotic changes in initial endoscopy. No complications occurred during or following the ligation procedure. CONCLUSIONS: Most gastric hyperplastic polyps develop avascular necrosis following ligation by detachable snare. Cyanotic change is an important predictor of the outcomes of the lesions following endoscopic ligation. The application of this ligation technique in treatment of bleeding or non-bleeding gastrointestinal polyps deserves further investigation.

Adolescent↗
PubMed2000

Drugs and prisoners: treatment needs on entering prison.

An interview study was conducted among a group of incoming prisoners in a county jail in Ohio during the summers of 1997 and 1998 to assess their current drug treatment needs. "Incoming prisoners" refers to individuals who were being transferred from this county jail to the state prison system. Marijuana and cocaine were the most commonly tried illegal drugs among the subjects as well as the drugs of choice during the month prior to imprisonment. The Diagnostic Interview Schedule, combined with questions employed in the Drug Use Forecasting (DUF) project, was used to construct the questionnaire for this study. Based on the criteria of DSM-IV diagnoses, 57.5% of those interviewed had exhibited drug dependency at some point in their lives, and 51% were currently dependent on some substance. Thus, more than half of the incoming prisoners were in need of treatment for use of at least one substance. Cocaine dependence was the greatest problem facing this group of inmates, with an especially notable problem among the older females. Younger males were more likely to have current marijuana dependence. The study found that individuals currently dependent on cocaine or opiates perceived that they had a need for drug treatment, while those currently dependent on marijuana did not share this perception.

Adolescent↗
PubMed2000

Effects of timing of diatrizoate (water-soluble contrast medium) administration on pancreatic microcirculatory derangement in cerulein pancreatitis in rats.

OBJECTIVE: We investigated whether the timing of administration of contrast medium after onset of acute pancreatitis is critical in determining the magnitude of microcirculatory derangement. METHODS: An acute pancreatitis model in male Sprague-Dawley rats (225-275 g) was established by continuous infusion of cerulein (15 mg/kg per hour). The mean arterial pressure was monitored continuously by means of a femoral artery catheter. Diatrizoate (Hypaque-76), a water-soluble contrast medium, was delivered through a femoral vein catheter at doses corresponding to those given to humans, either 1, 2, or 3 hours after pancreatitis induction. In vivo microscopy and laser-Doppler flowmetry were used to investigate microcirculatory derangement. The water contents of the pancreas and lung, the malondialdehyde levels of the pancreas, and the trypsinogen activation peptide levels in the serum were measured at the end of the experiment (8 hours after infusion of cerulein). RESULTS: Early administration of contrast medium (1 hour after pancreatitis induction) resulted in significantly greater changes in microcirculation and mean arterial pressure than did late administration (2 or 3 hours after pancreatitis induction). Rats given contrast medium 1 hour after induction also had highest pancreas and lung water contents, the highest pancreas malondialdehyde levels, and the highest serum trypsinogen activation peptide levels. CONCLUSION: These results show that a water soluble contrast medium that is often used for computed tomographic imaging of the pancreas can adversely affect the pancreatic microcirculatory parameters, such as tissue perfusion and leukocyte sticking, and hemodynamics in a cerulein-induced model of acute pancreatitis. Early administration seems to cause more severe derangement of the pancreatic microcirculation.

Acute Disease↗
PubMed2000

Gender differences in drinking patterns among Hong Kong Chinese youth: a pilot study.

About one year before the People's Republic of China regained political control of Hong Kong, a semistructured interview study was conducted among a group of 101 Hong Kong Chinese adolescents to explore their drinking behavior. The purpose of this exploratory study was to look for empirical evidence confirming the general hypothesis that wherever Chinese reside, they are moderate drinkers. Specifically, the study was designed to examine whether male and female adolescents gave different reasons for their drinking and nondrinking behavior, were differentially affected by parents' drinking, and experienced differential consequences resulting from alcohol use. The results confirm that Chinese youth in Hong Kong are moderate drinkers. Only minimal differences exist between the genders. The traditional Chinese normative view of alcohol may partly explain the results, an observation that suggests future research into the sociocultural features that influence drinking among youth.

Adolescent↗
PubMed1999

Determination of the antibiotic fungicide validamycin A in formulated products by micellar electrokinetic chromatography.

A micellar electrokinetic capillary chromatographic method (MEKC) was used to determine validamycin A content in commercial products. The results indicated that this method was capable of analyzing the validamycin A content in formulated products with an instrument detection limit of 0.94 microg/mL and a method detection limit of 1. 70 microg/mL. Relative standard deviation (RSD) values of MEKC determination of validamycin A in formulated products ranged from 0. 61 to 2.09%. Recoveries of validamycin A in formulated products were in the region of 99.5-105.1%. All commercial products collected from markets contained validamycin A. The high percentage of recovery, the low detection limit, and the low RSD values confirmed that the MEKC technique is a senstivie and selective method.

Anti-Bacterial Agents↗
PubMed1999

Aminoguanidine attenuates hemodynamic and microcirculatory derangement in rat intestinal ischemia and reperfusion.

BACKGROUND: Nitric oxide (NO) participates in the regulation of hemodynamic and microcirculatory changes in intestinal ischemia and reperfusion (I/R). However, the nature of the involvement of an inducible NO release has been controversial. This study evaluates the impact of an inducible NO synthase inhibitor, aminoguanidine, used as a treatment in a rat intestinal I/R model. METHODS: We investigated the hemodynamics by measuring the mean arterial pressure (MAP), and the microcirculatory responses of the intestine and liver to systemically administered aminoguanidine by use of laser-Doppler flowmetry (LDF), in vivo microscopy, and flow cytometry. RESULTS: During the 30-min ischemia of the selected 20-cm ileal segment, no MAP change was noted. At reperfusion, a marked decrease of MAP was noted and the lowest levels were noted 3 hours after reperfusion (67 +/- 4% vs. 99 +/- 5% in sham-operated control animals). A marked decrease in liver perfusion as measured by LDF was noted 1 hour after reperfusion and remained low at 5 hours (72 +/- 4% vs. 97 +/- 3% in sham-operated control animals). A marked decrease in intestine perfusion was noted by using LDF 1 hour after reperfusion and remained low at 5 hours (43 +/- 3% vs. 92 +/- 4% in sham-operated control animals). The flow velocity of the postcapillary venules of the intestine was markedly decreased (1.01 +/- 0.62 vs. 2.67 +/- 0.34 mm/s in sham-operated control animals) at 5 hours after reperfusion. The flow velocity of the postsinusoidal venules of the liver was also markedly decreased (1.01 +/- 0.62% vs. 2.67 +/- 0.34% in sham-operated control animals). Leukocyte-endothelial interaction (adhesion) was increased in the postcapillary venules of the intestine (54 +/- 12 vs. 6 +/- 4/microm2 in sham-operated control animals) and in the postsinusoidal venules of the liver (32 +/- 8 vs. 2 +/- 2/microm2 in sham-operated control animals). Concomitantly, the granulocyte count was increased (9.1 +/- 0.6 vs. 2.1 +/- 0.3% of total circulating leukocytes in sham-operated control animals), with an increase of CD 11b expression. Aminoguanidine administration (1 mg/kg) 0.5 hour before ischemia and 1 hour after reperfusion significantly increased MAP, increased intestine and liver perfusion, decreased adhesion, and decreased circulating granulocytes and CD 11b expression. CONCLUSION: Inhibition of an inducible NO release by aminoguanidine in intestinal I/R can attenuate hemodynamic and microcirculatory derangement.

Animals↗
PubMed1998

Effect of D57N mutation on membrane activity and molecular unfolding of cobra cardiotoxin.

Cobra cardiotoxins (CTXs) are able to adopt a three-fingered beta-strand structure with continuous hydrophobic patch that is capable of interacting with zwitterionic phospholipid bilayer. In addition to the four disulfide bonds that form the rigid core of CTXs, Asp57 near the C-terminus interacts electrostatically with Lys2 near the N-terminus (Chiang et al. 1996. Biochemistry. 35:9177-9186). We indicate herein, using circular dichroism and the time-resolved polarized tryptophan fluorescence measurement, that Asp57 to Asn57 (D57N) mutation perturbs the structure of CTX molecules at neutral pH. The structural stability of the D57N mutant was found to be lower, as evidenced by the reduced effective concentration of the 2,2,2-trifluoethanol (TFE)-induced beta-sheet to alpha-helix transition. Interestingly, the single mutation also allows a greater degree of molecular unfolding, because the rotational correlation time of the TFE-induced unfolding intermediate is larger for the D57N mutant. It is suggested that the electrostatic interaction between N- and C-termini also contributes to the formation of the functionally important continuous hydrophobic stretch on the distant end of CTX molecules, because both the binding to anilinonaphthalene fluorescent probe and the interaction with phospholipid bilayer were also reduced for D57N mutant. The result emphasizes the importance of the hydrophobic amino acid residues near the tip of loop 3 as a continuous part of the three-fingered beta-strand CTX molecule and indicates how a distant electrostatic interaction might be involved. It is also implicated that electrostatic interaction plays a role in expanding the radius of gyration of the folding/unfolding intermediate of proteins.

Anilino Naphthalenesulfonates↗
PubMed1996

Are women heavier drinkers than we thought they were?

OBJECTIVE: This study intended (1) to examine whether men are more likely to experience "male-type" problems related to drinking and women are more likely to encounter "female-type" problems and (2) to discover whether male or female collegians have higher blood alcohol concentrations (BACs) at a typical drinking session. METHOD: A questionnaire was administered to students enrolled in introductory courses in departments of social sciences at two state universities, situated in the Midwest and the South, in the spring term of 1994. Of the 2,056 students who constituted the sample of the present study, about 54% were women and 92.6% were white. The subject collegians' BACs during drinking episodes were indirectly estimated by three variables-quantity of alcohol consumed, individual body weight and duration of drinking session. RESULTS: The data indicate that men achieve a higher BAC than do females while drinking. When the incidence of various alcohol-related problems (both gender-biased and gender-neutral problems) was measured, it was found that, after drinking levels are controlled, gender becomes a significant factor in whether some alcohol-related problems will occur. CONCLUSIONS: Findings indicate that gender socialization may partly explain gender differences in the alcohol-related problems reported.

Adult↗