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Biomedical subjects

C Y Chan

Publications and source records attributed to C Y Chan.

At least 109 records · Page 6Linked to original sources
PubMed1994

Evaluation of three culture media and their combinations for the isolation of Mycobacterium tuberculosis from pleural aspirates of patients with tuberculous pleurisy.

The abilities of three culture systems to detect Mycobacterium tuberculosis from 480 pleural aspirate specimens in 347 patients were compared. The systems were the Bactec 12B radiometric detection system (Bactec 12B), the Middlebrook 7H9 broth (7H9), and two solid media including one pyruvate enriched Lowenstein-Jensen slope (LJP) and one non-selective Middlebrook 7H11 agar slope (7H11). In the 116 specimens obtained from 85 patients of confirmed pleural tuberculosis for the isolation of Mycobacterium tuberculosis, the diagnostic yields were 33 (39%) cases from Bactec 12B, 24 (28%) cases from 7H9 and 21 (25%) cases from LJP/7H11, with median detection times of 18, 47.5 and 44 days respectively. Thirteen isolates were recovered by the Bactec 12B only, 9 by the 7H9 broth only, and 2 by the LJP/7H11 agar only. The use of a combination of the three culture systems substantially increased the diagnostic yield to 47% over the individual systems. These results show that a significantly greater and faster diagnostic yield can be obtained by including Bactec 12B in pleural aspirate cultures for the recovery of Mycobacterium tuberculosis.

Biopsy, Needle↗
PubMed1994

Penicillamine hypersensitivity: successful desensitization of a patient with severe hepatic Wilson's disease.

We report a 16-yr-old patient who developed a severe allergic reaction to penicillamine which was prescribed for newly diagnosed hepatic Wilson's disease. The patient's name was placed on the liver transplant waiting list because of the severity of her liver disease. We describe successful desensitization to penicillamine, so that medical therapy alone was sufficient for management of her condition.

Adolescent↗
PubMed1994

Seroprevalence of antibody to hepatitis E virus among Chinese subjects in Taiwan.

Recently, with an available serological hepatitis E virus diagnostic kit, the prevalence of IgG antibody to hepatitis E virus among Chinese subjects in Taiwan was evaluated by means of a solid-phase enzyme-linked immunoassay based on two recombinant hepatitis E virus antigens. The overall prevalence of hepatitis E virus antibody was 10.7% among 384 healthy subjects older than 20 yr but only 0.3% among 600 schoolchildren and young adolescents younger than 20 yr (p < 0.0001). Serial serum samples from 32 hepatitis E virus antibody-positive healthy subjects showed 84% of them to have antibodies persisting more than 3 to 8 yr. Among patients with viral hepatitis, IgG hepatitis E virus antibody was detected in 10% of 10 patients with acute hepatitis A, in 9.5% of 63 patients with acute hepatitis B and in 13.9% of 36 patients with acute posttransfusion hepatitis C. Of 77 patients with sporadic non-A, non-B hepatitis, IgG hepatitis E virus antibody was detected in 18.9% of 53 patients positive for antibody to hepatitis C virus and in 45.8% of 24 patients negative for hepatitis C virus antibody (p < 0.03). Most of our hepatitis E virus antibody-positive normal subjects and patients had never been abroad. These findings demonstrate that sporadic or subclinical hepatitis E virus infections also exist among the Chinese subjects in Taiwan. Hepatitis E virus infection may play an important role in patients with hepatitis C virus antibody-negative sporadic non-A, non-B hepatitis. IgG hepatitis E virus antibody in the sera of normal subjects may last for more than 8 yr.

Adolescent↗
PubMed1993

Immunogenicity of inactivated hepatitis A vaccine in children.

BACKGROUND: Inactivated hepatitis A vaccine is now becoming available in many countries. METHODS: To evaluate the immunogenicity and safety of inactivated hepatitis A vaccine in healthy children, 99 susceptible schoolchildren from 4 to 15 years of age received 360 enzyme-linked immunosorbent assay units of the inactivated hepatitis A vaccine at months 0, 1, and 6. RESULTS: Antibody to hepatitis A virus seroconversion (> or = 20 mIU/mL) was 97% (96/99) in vaccinees after the first dose and 100% after the second (99/99) and booster (96/96) doses. The geometric mean titers of antibody to hepatitis A virus were 167, 465, and 4133 mIU/mL after each dose of vaccine, respectively. There were no significant side effects during the vaccination. Levels of antibody to hepatitis A virus were also tested in 9 susceptible children at day 7 and months 1 and 4 after the intramuscular injection of 2 mL of immune serum globulin. All children had measurable titers of antibody to hepatitis A virus 1 week after receiving immune serum globulin by sensitive enzyme immunoassay, but measurable titers had disappeared 1-4 months later. CONCLUSIONS: The inactivated hepatitis A vaccine is safe and immunogenic in healthy children.

Adolescent↗
PubMed1993

Postantibiotic effects of amikacin and ofloxacin on Mycobacterium fortuitum.

A study of postantibiotic effects (PAE) in vitro of amikacin and ofloxacin on Mycobacterium fortuitum isolates from sternotomy wounds by use of the dilution method for drug removal showed that both drugs exhibited good bactericidal activities, with the PAE of amikacin lasting from 13.5 to 27.6 h and the PAE of ofloxacin lasting from 1.2 to 5.0 h. These laboratory results concur with our experience of the efficacy of once-daily dosing with these drugs in the treatment of infections caused by M. fortuitum. These data may have therapeutic implications in guiding the scheduling of the administration of drugs in these infections, which require a long duration of therapy.

Amikacin↗
PubMed1993

Influence of thalassemia on the response to recombinant human erythropoietin in dialysis patients.

Thalassemia is a common genetic disorder among the South Chinese. To see if thalassemia would adversely affect the erythrocyte response to recombinant human erythropoietin (rHuEPO, Epogen) in dialysis patients, the response to rHuEPO in 4 dialysis patients with thalassemic traits (thal-t) was compared with that of 4 control patients who were matched for age, sex, mode of dialysis and baseline hemoglobin levels over a 6-month period. Patients with thal-t showed a reduced erythrocyte response to rHuEPO compared to control dialysis patients as reflected by a reduced reticulocyte index, a slower rise in hemoglobin or hematocrit levels, requirement of a higher cumulated dose of rHuEPO to achieve a target hemoglobin of 10 g/dl and a higher maintenance dose of rHuEPO. A dialysis patient with hemoglobin H disease (HbHD) was also studied. He failed to respond to rHuEPO despite that the dose was increased to 250 U/kg/week. In contrast, his matched control dialysis patient, despite a lower baseline hemoglobin level (6.1 versus 8.8 g/dl), was able to reach a target hemoglobin level of 10 g/dl by 6 weeks and could be maintained at this level with 50 U/kg/week. The patient with HbHD had splenomegaly and a higher baseline serum erythropoietin level, reticulocyte count, serum bilirubin, serum ferritin and serum iron saturation than control patients and patients with thal-t. It was concluded that thal-t reduces the erythrocyte response to rHuEPO in dialysis patients and that in the presence of active hemolysis and enhanced endogenous erythropoietin secretion, dialysis patients with HbHD are resistant to treatment with rHuEPO.

Adult↗
PubMed1993

Correlation of serum ofloxacin concentration and serum creatinine level in patients on prolonged therapy.

Serum ofloxacin concentrations were assessed by high performance liquid chromatography 4 h after drug administration in 86 patients with pulmonary tuberculosis. All patients had multidose, once-daily drug administration (200 mg to 800 mg p.o.) for at least 3 weeks prior to assessment. The serum creatinine levels were simultaneously assessed for these patients. A positive correlation was found between serum ofloxacin (Y) and serum creatinine x dose of ofloxacin administered/body surface area (X). The correlation can be represented mathematically by the equation: Y = 0.87X + 0.68 (r = 0.80, p < 0.001).

Adolescent↗
PubMed1993

The requirement of low calcium dialysate in patients on continuous ambulatory peritoneal dialysis receiving calcium carbonate as a phosphate binder.

In the present study we investigated the requirement of low calcium dialysate in 35 patients on continuous ambulatory peritoneal dialysis (CAPD) receiving calcium carbonate as the sole phosphate binder over a 12-month period. Patients with corrected serum calcium > or = 2.85 mmol/L after switching to oral calcium carbonate were given 1 to 3 2-litre exchanges of 2.5 mEq/L calcium dialysate. Serum phosphate level dropped from the pretreatment value of 2.95 +/- 0.62 to a level of between 1.70 +/- 0.41 to 2.03 +/- 0.44 mmol/L 2 weeks after therapy. Corrected serum calcium level increased significantly from 2 weeks onwards. Serum alkaline phosphatase rose initially at 2 and 6 weeks and decreased from 3 months onwards. Serum parathyroid hormone level dropped significantly from a mean pretreatment level of 569 to 320 pg/ml after 12 months (p < 0.001). Serum aluminum decreased significantly from a mean of 1.04 to 0.65 umol/L (p < 0.01). Daily calcium carbonate requirement fluctuated but tended to increase till 8 months and plateaued and ranged from 2.61 +/- 0.57 to 3.98 +/- 2.11 gm. The daily requirement of low calcium dialysate followed a similar trend with approximately three-quarters of patients ultimately requiring at least 1 bag of low calcium dialysate. Eight patients did not require low calcium dialysate. Patients who required low calcium dialysate were significantly older, had a significantly lower pretreatment serum parathyroid hormone and higher serum aluminum levels than those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Lack of activities of amikacin and sulphamethoxazole against Mycobacterium avium-intracellulare.

Twenty clinical isolates of Mycobacterium avium-intracellulare were tested with amikacin and sulphamethoxazole for in-vitro susceptibilities. The MICs and MBCs of the former drug ranged from 8 to > 64 mg/L (median MIC: 64 mg/L, median MBC: > 64 mg/L). The MICs and MBCs of the latter drug were found to be > 256 mg/L. Each of eight patients with invasive pulmonary disease due to these organisms was treated with amikacin for six months and with cotrimoxazole (sulphamethoxazole-trimethoprim) for one year. Only one patient had sustained bacteriological conversion. Three patients showed a transient reduction of bacillary load during the period of amikacin administration. The rest all failed to show response. Thus sulphamethoxazole was found to have no activity against Mycobacterium avium-intracellulare, and amikacin has doubtful activity when used alone in treatment of M. avium-intracellulare infection.

Adult↗
PubMed1993

A randomized prospective comparison of oral versus intraperitoneal ciprofloxacin as the primary treatment of peritonitis complicating continuous ambulatory peritoneal dialysis.

The present study compared oral versus intraperitoneal (ip) ciprofloxacin (ciproxin) as primary treatment of bacterial peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD) in a randomized, prospective trial. A total of 54 episodes in 46 patients were recruited for study. After excluding nonbacterial episodes and those not treated according to protocol, 48 episodes evenly divided between the two treatment arms were eligible for analysis. The primary cure rate was 41.7% and 66.7%, respectively, in the oral and ip treatment group. Half of those who failed or relapsed were due to infection with resistant, mostly gram-positive bacteria, which accounted for 79% of culture-positive episodes. Of the gram-positive isolates 42.3% were either resistant or intermediately susceptible to ciproxin compared to 16.7% of gram-negative isolates. The high level of bacterial resistance to ciproxin and treatment failure rate were related to the previous exposure to fluoroquinolones. Inadequate trough peritoneal drug levels also accounted for the failures in the ip but not the oral treatment group. We conclude that oral ciproxin is ineffective as a primary treatment of CAPD peritonitis in patients previously exposed to fluoroquinolones and that when administered ip, a dose of 50 mg/L instead of 25 mg/L of ciproxin should be used as maintenance in order to achieve adequate trough peritoneal drug levels.

Administration, Oral↗
PubMed1993

Single-dose pharmacokinetics of intraperitoneal ofloxacin in patients on continuous ambulatory peritoneal dialysis.

The present study examines the pharmacokinetics of ofloxacin given in a single dose of 200 mg intraperitoneally (ip) in the first bag of three 2-L 8-hour exchanges. Ofloxacin was measured using high-pressure liquid chromatography (HPLC) in the serum and peritoneal effluent over 24 hours. Six patients without and 3 patients with peritonitis were studied. Ofloxacin given ip was almost completely absorbed after an 8-hour dwell, and this was not affected by peritonitis. The time required to reach peak serum concentration was longer than that reported previously following oral administration. Elimination half-life (T1/2) of ofloxacin was markedly prolonged compared to patients with normal renal function. Peritoneal clearance accounted for only one-tenth of total serum clearance. Peritonitis appeared to shorten the T1/2 of ofloxacin, but this was mainly due to an increase in total serum clearance rather than a change in peritoneal clearance. Peritoneal drug concentration > 0.5 mg/L was reached in the second and third exchange by the second hour. No side effects from ip ofloxacin were observed. We concluded that ofloxacin given in a single dose of 200 mg is safe and provides adequate therapeutic serum and peritoneal concentration for more than 24 hours in patients on continuous ambulatory peritoneal dialysis (CAPD) with 8-hour exchanges.

Aged↗
PubMed1992

Relationship of portal pressure, anorectal varices and hemorrhoids in cirrhotic patients.

In a prospective study of 103 consecutive cirrhotic patients a high prevalence (43%) of anorectal varices was found compared with only 2% in 103 age- and sex-matched control subjects (p less than 0.001). However, there was no significant difference between the prevalences of hemorrhoids in cirrhotic patients and in control subjects (79% vs. 83%, p greater than 0.05). The hepatic venous pressure gradient of cirrhotic patients with anorectal varices was similar to cirrhotic patients without anorectal varices (14 +/- 6 mmHg, n = 22, vs. 16 +/- 7 mmHg, n = 39, p greater than 0.05. There was no significant difference in the hepatic venous pressure gradient between cirrhotic patients with and without hemorrhoids (15 +/- 6 mmHg, n = 47, vs. 16 +/- 8 mmHg, n = 14, p greater than 0.05). The prevalence of anorectal varices and hemorrhoids in cirrhotic patients had no relation to Child-Pugh's grading, esophageal varices with and without sclerotherapy and ascites. We conclude that anorectal varices are common in cirrhotic patients. Anorectal varices and hemorrhoids are not related to the degree of portal pressure.

Aged↗
PubMed1992

Effect of biliary obstruction on the hepatic excretion of imipenem-cilastatin.

The biliary excretion of imipenem-cilastatin studied by endoscopic cannulation of the common bile duct in patients with complete obstruction and in a group without obstruction showed that despite a 24-h prophylaxis, the bile obtained from patients with obstruction immediately after cannulation contained neither imipenem nor cilastatin, while there were 2 and 5% of peak concentrations in serum for imipenem and cilastatin, respectively, in the bile from patients without obstruction. Biliary excretion of both compounds increased rapidly after decompression, reaching a maximum of 15% of peak levels in serum within 2 h. Twenty-four hours after drainage, the biliary excretion of the drugs further improved. We conclude that since biliary obstruction impairs excretion of antibiotics, drainage is necessary for the control of sepsis in obstructed cholangitis.

Adult↗
PubMed1992

Membrane and synaptic activity during anoxia in the isolated turtle cerebellum.

Electrical depression in the turtle brain during anoxia has been suggested as a strategy for sparing energy and promoting the extraordinary survival capacity of this tissue. The present study was aimed toward defining the changes in membrane properties during anoxia that may underlie such electrical depression. Studies were conducted in isolated cerebellum from turtle brain. Anoxia caused transmembrane potentials (TMP) to become relatively less polarized in most Purkinje cells. In no cell, however, was TMP depolarized to levels associated with the complete loss of transmembrane ion gradients produced by tissue superfusion with iodoacetate during anoxia. Sodium (and likely calcium) spike thresholds were increased, postsynaptic responses from the major afferent input pathways to Purkinje cells were depressed, and input resistance decreased significantly during anoxia. These changes likely contribute to the sparing of energy needed for ion transport and perhaps other functions that may be directly related to cell survival.

Action Potentials↗
PubMed1992

Endoscopy for upper gastrointestinal bleeding at emergency unit.

From November 1, 1990 to January 31, 1991, 381 patients visited our emergency unit with the chief complaints of hematemesis (n = 153) and melena (n = 228). Of these patients, 298 (78.2%) received UGI endoscopy at the emergency unit, 29 (7.6%) received examination after they were admitted to wards, 3 (0.8%) received endoscopy at outpatient clinic and 51 (13.4%) did not have endoscopy. The percentages of endoscopic diagnoses in 330 patients who had UGI endoscopy were gastric ulcer (GU) 33.6%, duodenal ulcer (DU) 32.7%, esophageal varices (EV) 17.0%, and others 15.5%. Negative findings were noted in 3 cases and no definite bleeding source was found in 1 patient who had blood retention in stomach. The diagnostic rate of endoscopy was 98.8%. Of the 56 patients with EV, 45 (80.4%) had hematemesis; in contrast, 85 of the 108 DU patients (78.8%) complained of melena only. Of the 219 patients with bleeding GU/DU, 64 (29.2%) had endoscopic therapies and 7 (3.2%) needed operation. Sixty-four (29.2%) of them received UGI endoscopy within 6 hours after arrival. They had significantly higher frequency of stigmata of recent hemorrhage (SRH) and more endoscopic therapies than the remaining patients. The overall mortality rate in our patients was 6.0%; the mortality rate in patients with EV was much higher than that of the patients with GU/DU (19.6% vs. 1.8%, P less than 0.001). Of the 23 expired cases, only 11 died of hypovolemic shock. The remaining 12 patients died of deterioration or complications of their underlying diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Long-term follow-up of hepatitis B vaccination in infants born to noncarrier mothers in Taiwan.

Two hundred and seventy-seven infants born to hepatitis B surface antigen (HBsAg)-negative noncarrier mothers had been divided into 3 groups to receive 1 microgram, 2 micrograms or 5 micrograms of plasma derived hepatitis B vaccine and were followed up annually to the age of 6. At the end of the follow-up period, the antibody to HBsAg (anti-HBs) positive rates in these 3 groups were 63.0% (58/92), 77.9% (74/95) and 83.3% (75/90), respectively (group 1 vs. group 2, p less than 0.05; group 1 vs. group 3, p less than 0.01; group 2 vs. group 3, p greater than 0.05). Among the initial responders, 25 of 38 (65.8%) with low initial anti-HBs titers (10-100mIU/ml) and 18 of 79 (22.8%) with medium initial anti-HBs titers (101-1,000mIU/ml) were found to be anti-HBs seronegative, while only 2 of 136 (1.5%) with high initial anti-HBs titers (greater than 1,000 mIU/ml) lost their anti-HBs (P less than 0.01). None of the vaccinees became HBsAg positive but 1 initial responder became positive for anti-HBc at the age of 4. Twenty-five initial nonresponders and 18 initial responders who lost their anti-HBs at the age of 2 received a second booster of vaccination at the age of 3. Five (20.0%) of the initial nonresponders and 17 (94.4%) of the initial responders responded to the second booster. The annual incidence of natural booster was 2.1%. In conclusion, the standard doses of 5 micrograms plasma-derived vaccine tend to be the best choice for immunization of infants born to noncarrier mothers in Taiwan.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1991

Analysis of factors associated with bronchial hyperreactivity to methacholine in bronchiectasis.

Nonspecific bronchial hyperreactivity (BHR) has been reported to occur in patients with bronchiectasis. To evaluate this further, we studied 77 patients with stable bronchiectasis (noncystic fibrosis) with special reference to the prevalence of BHR to methacholine (MCh), and its relation to lung function, sputum characteristics, concommitant asthma, and atopy. The concentration of MCh required to produce a fall of 20% in forced expiratory volume in 1 s (FEV1), PC20, was determined by Wright's nebulization tidal breathing method. BHR defined by a PC20 greater than or equal to 8 mg/ml was found in 21 of 47 (45%) subjects who underwent bronchial challenge. Presence of BHR was positively associated with low baseline spirometric values, diagnosis of asthma, long duration of disease, and elevated total IgE on univariant analysis, and was significantly related to FEV1/forced vital capacity (FVC) ratio and asthma on multiple regression analysis. Ten of the 21 hyperreactive subjects did not have clinical asthma, whereas all 11 of 22 subjects with clinical asthma who underwent bronchial challenge were hyperreactive. Among those with BHR, there was a positive correlation between PC20 and baseline FEV1. When patients were further classified into asthmatic and nonasthmatic subjects, a positive correlation between PC20 and FEV1 was seen only in those without asthma. Frequency of infective episodes and inflammatory score of sputum assessed by average daily volume, purulence, and leukocyte count did not differ significantly in the groups with and without BHR. These results suggest that BHR in patients with bronchiectasis is associated with coexistent asthma and worse spriometric values, and not with the severity of bronchial sepsis.

Adult↗