Biomedical subjects

W K Chang

Publications and source records attributed to W K Chang.

At least 37 records · Page 2Linked to original sources

PubMed1998

Anesthetic management of a parturient with Eisenmenger's syndrome and preeclampsia during cesarean section--a case report.

It has been recommended that women with Eisenmenger's syndrome (ES) are better not to become pregnant and pregnancy may justifiably be terminated by artificial abortion to avoid high maternal mortality and coherent fetal mortality. We present a case report about a parturient with ventricular septal defect (VSD) and ES who received general anesthesia for Cesarean section (C/S) because of preeclampsia, as a result of which she finally succumbed to an episode of intraoperative hypotension in spite of vigorous cardiopulmonary resuscitation. The death was thought to be precipitated by continuous deterioration of maternal health during the 3rd trimester of gestation. The anesthetic management of pregnant ES patients in confinement was reviewed and discussed, and the possible etiological factors relevant to the tragic outcome were also explored.

Adult↗

PubMed1997

Helicobacter pylori infection and the risk of gastric cancer among the Korean population.

Helicobacter pylori infection has been associated with chronic atrophic gastritis, a precursor of gastric cancer. We conducted a prospective, case-controlled study to investigate whether H. pylori infection increases the risk of gastric cancer in Korean people with a high risk of gastric cancer. We enrolled 160 gastric cancer patients who were confirmed by endoscopic biopsy during 1994 and 160 age-matched control subjects with non-ulcer dyspepsia were compared to document the relationship between H. pylori infection and gastric cancer. The presence of H. pylori infection was determined by the rapid urease test and/or histology by Wright-Giemsa staining. The overall presence of H. pylori infection was 60% in gastric cancer patients and 51.9% in age-matched control subjects (odds ratio 1.39; 95% confidence interval 0.894-2.17; P = 0.143). Carcinomas of cardia, body and antrum were not associated with H. pylori infection (odds ratio 1.43, 1.69 and 1.29, respectively; 95% confidence interval, 0.271-7.52, 0.787-3.62 and 0.689-2.43, respectively; P = 0.178, 0.177 and 0.642, respectively) nor was the intestinal or diffuse type of cancer (odds ratio 1.39 and 1.40, respectively; 95% confidence interval 0.791-2.45 and 0.681-2.87, respectively; P = 0.250 and 0.835, respectively). Gender was not a risk for gastric cancer. In contrast to previous studies, these results do not provide evidence of H. pylori infection for gastric carcinogenesis in Korea.

Adenocarcinoma↗

PubMed1997

Mixed meningococcal and tuberculous meningitis.

Meningococcal meningitis is one of the most common bacterial infections of the meninges worldwide, and tuberculous infection is the most common cause of chronic meningitis in Taiwan. However, mixed meningococcal and tuberculous meningitis is rare. We describe a 27-year-old woman with a case of culture-proven meningococcal and tuberculous meningitis verified by polymerase chain reaction on a cerebrospinal fluid specimen. The patient was initially treated with intravenous antibiotics including penicillin G and chloramphenicol. Though the patient responded well to therapy initially, her subsequent clinical deterioration was finally controlled by long-term antituberculous medications.

Adult↗

PubMed1997

Truncal rigidity as a result of epidural sufentanil--a case report.

It is well known that intravenous opioids may cause truncal rigidity. To the best of our knowledge truncal rigidity induced by epidural opioid has never been reported. Recently, we came across an accident of truncal rigidity following epidural sufentanil. The victim was a 65-year-old female who received cholecystectomy, choledochotomy, and cholangiography. For post-operative pain control, an epidural catheter was inserted cephalad [corrected] at L1-2 interspace with a length of 4 cm of the catheter retained in the epidural space. The epidural catheter was secured and tested for correct placement with 3 ml of 2% lidocaine with 1:200,000 epinephrine prior to induction of general anesthesia. No opioid was ever given in the operative course. When the patient was fully awake and complained of wound pain in the recovery room 50 mg of sufentanil in 10 ml normal saline was given via the epidural catheter after a negative evacuation test. About one minute after the epidural shot, she was found to lose consciousness without any slightest warning sign. Truncal rigidity and locked jaw that followed entailed respiratory arrest and rapid deterioration of oxygenation which evidenced a life-threatening airway emergency. It spite of our efforts we could not manage to ventilate her with ordinary means. It was not until the administration of 80 mg of succinylcholine and oral endotracheal intubation could an adequate ventilation be reestablished. She regained spontaneous breathing 15 min after the episode but for safety's sake she remained intubated for 6 h until the dissipation of analgesia. Another test dose was attempted, which reconfirmed that the epidural catheter was in proper position. She stayed in the recovery room for 24 h and returned to ward in satisfactory condition. The incidence disclosed that epidural sufentanil even with a dose as small as 50 micrograms could cause truncal rigidity. Thus when epidural sufentanil is applied for post-operative pain control constant vigilance is necessary in order to avoid accident.

Abdomen↗

PubMed1996

A child of suspected malignant hyperthermia during general anesthesia for dental surgery.

Malignant hyperthermia is clinically an uncommon disorder characterized by acute hypercatabolic reactions in muscles in response to the triggering effects of certain drugs mainly used during anesthesia or to physical or emotional stress. We present a pediatric patient with multiple caries who was suspected to contract malignant hyperthermia while underwent the operative procedure of comprehensive restoration. Sinus tachycardia, hyperthermia, hypercapnia, metabolic acidosis, hyperkalemia and hypercalcemia developed unexpectedly during the operation. Fortunately, the patient survived the episode with early recognition and prompt management.

Anesthesia, General↗

PubMed1995

Guided tissue regeneration demineralized freeze-dried bone allograft: treatment of furcation defects in mandibular molars.

The present study evaluated the effects of combined guided tissue regeneration (GTR) and demineralized freeze-dried bone allograft (DFDBA) therapy on the healing of grade III furcation lesions in mandibular molars of seven periodontitis patients. De novo surgical debridement of furcation roofs by fine diamond bur was introduced. Routine presurgical preparation of teeth and a strict plaque control program were performed for at least six weeks before surgery. A papillary conserved full thickness mucoperiosteal flap was used in all cases. In addition to conventional debridement, odontoplasty was performed on the furcation areas with a diamond bur to eradicate inaccessible fissures or grooves and ensure calculus-free root surfaces. Following debridement, the bony defects were filled with DFDBA and covered with polytetrafluoroethylene (ePTFE) membranes. The flaps were then closed by interproximal sutures coronally positioned through the contact point. The ePTFE membranes were removed 6 to 7 weeks after operation. Clinical parameters such as probing depth (PD), gingival recession (GR), probing attachment level (PAL), tooth mobility (TM), and periapical x-ray were recorded at the baseline and 0, 3, 6, 9, and 12 months after removal of the ePTFE membrane. The results showed a significant increase in the probing attachment level and radiographic evidence of bone fill at the furcation sites. Thus, the addition of fine diamond bur debridement on the furcation in the GTR procedure with DFDBA grafting may be effective in the treatment of grade III furcation involvement.

Adult↗

PubMed1995

An investigation of whether polymorphisms of cytochrome P4502E1 are genetic markers of susceptibility to alcoholic end-stage organ damage in a Chinese population.

The human cytochrome P4502E1 gene (P4502E1), coding for an ethanol-inducible nitrosamine-metabolizing P-450, is involved in the metabolism of ethanol and many known carcinogens. Recently, restriction fragment length polymorphisms (RFLPs) within the P4502E1 have been suggested as genetic markers of susceptibility to alcohol-induced liver disease but the previous studies disagree whether alcoholics with c1 or c2 allele are more susceptible to alcohol-induced liver diseases. Using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, we determined the RsaI and PstI polymorphism of P4502E1 in 77 Chinese alcoholic patients (54 with alcohol-induced cirrhosis and 23 with acute alcohol-induced pancreatitis) and 164 non-alcoholics and compared them with previously published data. The PCR-RFLPs showed three P4502E1 genotypes: type A, homozygote c1/c1; type B, heterozygote c1/c2; and type C, homozygote c2/c2. The RsaI and PstI polymorphism of P4502E1 were completely linked in both Chinese alcoholics and nonalcoholic controls. The rare allele (c2) occurs at similar frequency of 0.232 and 0.234 (P > .05) in nonalcoholic controls and alcoholics, respectively. The genotype distributions of P4502E1 between Chinese alcoholics and nonalcoholics are not significantly different. The genotype and allele frequencies of P4502E1 for Chinese are significantly different from those of Swedes, European-Americans, and African-Americans, respectively (P < .00001), but very similar to Japanese (P > .05). In conclusion, ethnic variations exist between Asians and Caucasians and between Asians and African-Americans. No allelic variants at loci associated with RsaI/PstI RFLPs result in phenotypes displaying greater susceptibility to alcohol-induced cirrhosis or alcoholism in Chinese populations, which contradicts previous reports from Japanese groups.

Adult↗

PubMed1995

Evaluation of stress response to surgery under general anesthesia combined with spinal analgesia.

BACKGROUND: Each type of anesthesia has varying influence on the amount of catecholamine secretion during surgery. Epidural or spinal anesthesia can markedly suppress the increase of many of the stress hormones. Our purpose of this study is to evaluate metabolism change during surgery under anesthesia and to see whether general anesthesia combined with intraspinal anesthetic and narcotic is a better way to suppress such stress response. METHODS: Seventeen patients in fit physical condition (ASA class I) with normal biochemical screening scheduled for radical gastrectomy were studied. All patients were premedicated with diazepam and glycopyrrolate and an indwelling catheter was inserted into a radial artery under local anesthesia for monitoring blood pressure and obtaining blood samples for glucose and hormonal assays. A CVP line was set up via the right internal jugular vein for the administration of fluid (free of sugar). In the study group, a 32-G intraspinal catheter was placed via lumbar interspaces. Spinal blockade up to T4 by titrating 0.25% marcaine. Then anesthesia in both groups was induced with thiopental 5 mg/kg, followed by succinylcholine 1.5 mg/kg for intubation. Anesthesia was maintained with isoflurane, N2O, O2 and pancuronium. Blood samples for measurement cortisol, catecholamine and sugar were taken after induction and 30 min after surgical incision. Thirty min after skin incision all patients were subjected to glucose tolerance test, accomplished by giving 50% dextrose at 0.33 g/kg in 3 min. Arterial blood samples were then obtained at 1, 3, 5, 7, 10, 20, 30, 45 and 60 min intervals for plasma glucose determination. RESULTS: No difference was evident in cortisol values, baseline, before and after surgical incision (p > 0.05) either intragroup or inter-group. Catecholamine and glucose were significantly higher in control group after surgical incision (p < 0.05, intra-gr and inter-gr). Following a glucose load the decay of plasma glucose was similar in both groups but glycemic level was higher in the control group. CONCLUSIONS: Better control of stress response by general anesthesia combined with subarachnoid block was disclosed in this study.

Aged↗

PubMed1994

Alkaline phosphatase activity in cultured cells of human healthy and hyperplastic gingivae: a preliminary study.

The present study compared the alkaline phosphatase (ALP) expression in cultured cells derived from different types of gingival hyperplasia. Tissue biopsies were obtained from patients with clinically non-inflamed, enlarged gingivae of idiopathic gingivofibromatosis (IGF) and phenytoin-induced hyperplasia (PHG). Fibroblasts obtained from the gingivae or periodontal ligaments (PDL) of the same or different healthy subjects were used as controls. Fibroblasts were plated and the ALP activity and total amount of DNA per well were studied in each isolated cell type at 4, 7 and 9 days of culture. The results revealed that fibroblasts derived from IGF tissue synthesized a large amount of ALP by day 7 and day 9 of culture. The amount of ALP activity was cell density-dependent and the strongest expression of enzyme activity was noted after cell confluence. In contrast, only very low ALP activity was detected in cells derived from normal gingivae and PHG. Cytochemical examination of these cells revealed similar observations. The fact that fibroblasts derived from PHG tissue did not exhibit ALP in vitro suggests that there was a shift of cell phenotype in this tissue. The increased expression of ALP in IGF cells may imply a developmental trend toward osteoblastic phenotypes.

Alkaline Phosphatase↗

PubMed1994

Increased interleukin-1 beta levels in gingival crevicular fluid of Chinese periodontal patients.

One hundred and twenty-four gingival crevicular fluid (GCF) samples were harvested from 13 healthy and 111 diseased gingival sites in 10 patients with periodontitis. The total amount and concentration of interleukin-1 beta (IL-1 beta) in each sample was measured by the enzyme-linked immunosorbent assay (ELISA) technique using an ELISA Kit specific for this cytokine. The IL-1 beta was undetectable in 23% of the GCF from clinically non-inflamed sites (three out of 13), while it could mostly be identified in diseased sites (109/111). The amount of IL-1 beta varied from 4.03 to 511.12 pg/site in diseased GCF samples. The average IL-1 beta amount from diseased sites was three-fold that from non-inflamed sites. Total IL-1 beta amount and the GCF volume were significantly increased with elevated gingival index (GI) score and deeper probing depth (PD). However, no significant difference of crevicular IL-1 beta concentration (pg/microL) could be found among groups with different clinical parameters. Our results indicate that IL-1 beta was present in the GCF of most clinically non-inflamed gingiva and almost all diseased pockets. The significant elevation of total IL-1 beta amount and GCF volume in diseased sulci suggests that it is closely associated with the severity of periodontal disease.

Adult↗

PubMed1994

Rapid and specific detection of the leukotoxin sequences of Actinobacillus actinomycetemcomitans from periodontal pockets by the polymerase chain reaction.

Actinobacillus actinomycetemcomitans (Aa) has been implicated in most cases of localized juvenile periodontitis and some cases of severe adult periodontitis and refractory periodontitis. The Aa leukotoxin plays an important role in the pathogenesis of Aa associated periodontal disease. Rapid detection of Aa in a periodontal pocket is hampered by the slow growth and fastidious nature of this bacterium. In this study, we developed a rapid, sensitive, nonradioactive polymerase chain reaction (PCR) to identify a unique As sequence directly from subgingival plaque samples. Two oligonucleotide primers derived from DNA sequences of the leukotoxin gene were used in the PCR. The Aa-specific DNA fragments were analyzed by agarose gel electrophoresis and then visualized under 302 nm ultraviolet light after staining with ethidium bromide. In the 12 subgingival plaque samples screened, the Aa-specific sequences were found in five out of nine sites with periodontitis. No Aa-specific sequence was found in three healthy sites. The specificity of the amplified DNA fragments was confirmed by direct DNA sequencing. These results indicated that the PCR technique should assist in the rapid detection of Aa in subgingival plaque samples. Moreover, combined with direct DNA sequencing, this method can be used to study the molecular epidemiology of this periodontal pathogen.

Actinobacillus Infections↗

PubMed1993

Five-year follow-up of a prospective randomized trial of hepatitis B recombinant DNA yeast vaccine vs. plasma-derived vaccine in children: immunogenicity and anamnestic responses.

In a prospective randomized trial, 318 children aged between 3 mo and 11 yr who were negative for all hepatitis B markers were randomized to receive two 5-micrograms doses of hepatitis B recombinant DNA yeast vaccine at 0 and 1 mo (group 1), three 5-micrograms doses of hepatitis B recombinant DNA yeast vaccine at 0, 1 and 6 mo (group 2) or three 10-micrograms doses of plasma-derived hepatitis B vaccine (group 3). The HBs antibody response rate at 8 mo was between 93% and 99%; it was still 75% to 87% at 5 yr in all three groups. Geometric mean titers at 1 yr were 83, 1,085 and 858 mIU/ml in groups 1, 2 and 3, respectively. These values had decreased after 5 yr to 47, 131 and 250 mIU/ml. Subjects in group 1 showed a significantly less proportional drop in geometric mean titer at the fifth year than did subjects in group 2 (p = 0.05) or group 3 (p = 0.015). None of the children developed HBc antibody, even after 5 yr of follow-up. We noted 42 episodes of significantly increased HBs antibody titers, probably due to anamnestic response, even when the titers had dropped to low levels. The mean age at which anamnestic response occurred was 8.7 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1993

Polymorphonuclear neutrophil chemotaxis in Chinese patients with post-juvenile periodontitis and rapidly progressive periodontitis.

The purpose of this study was to investigate polymorphonuclear neutrophil (PMN) chemotaxis in Chinese patients with post-juvenile periodontitis (post-JP) and rapidly progressive periodontitis (RPP). Peripheral blood PMNs were isolated from nine post-JP and 13 RPP patients. Eight patients with adult periodontitis (AP) and seven clinically healthy subjects were used for comparison. Clinical data, including the plaque index and gingival index, of each subject were recorded. The "modified Boyden chamber technique" was used for PMN chemotaxis assay. Our results showed that the PMN chemotaxis index in patients with post-JP and RPP were significantly depressed compared to that in healthy subjects or patients with AP. There was no significant difference in PMN chemotaxis between post-JP and RPP, or between AP and healthy subjects. There was also no significant correlation between the plaque index, or gingival index, and PMN chemotaxis in any group. These results suggest that there is a PMN chemotaxis defect in most Chinese patients affected by post-JP or RPP, and that the PMN chemotaxis defect is not associated with clinical parameters such as the plaque index or gingival index.

Adult↗

PubMed1993

[Pheochromocytoma].

Pheochromocytoma is a rare tumor which develops in chromaffin cells and secrets excessive catecholamine. Unless patients harboring this uncommon tumor are exactly diagnosed preoperatively, well prepared, and protected from the effects of excessive catecholamine release, they are greatly at risk when undergoing any surgical procedures. This brief review contains the clinical symptoms, signs and syndromes associated with pheochromocytoma, the diagnostic methods which may identify and localize the lesion, the regimens of preoperative preparation and pharmacological control, the anesthetic management which has proved safe and effective in many patients, the anesthetic agents which may be contraindicated in some patients, and the postoperative management.

Adrenal Gland Neoplasms↗

PubMed1992

Significance of isolated anti-HBc seropositivity by ELISA: implications and the role of radioimmunoassay.

Hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) are excellent markers for HBV infection and its immunity. The significance of isolated antibody to HBV core antigen (anti-HBc) seropositivity is not certain. To elucidate this, sera from 638 Chinese adult subjects, aged 18-52 years, seronegative for both HBsAg and anti-HBs, were tested for anti-HBc. Fifty-one (8%) were found to have an isolated anti-HBc seropositivity by ELISA, and all were negative for IgM-anti-HBc. The anti-HBc persisted in all subjects who attended follow-up for hepatitis B vaccination (n = 48) for a period of 8 months. These 48 subjects received 3 doses of hepatitis B vaccine (HB-VAX, 10 micrograms or 20 micrograms) at 0, 1, and 6 months: 72.9% developed a primary anti-HBs response (suggestive of a false-positive anti-HBc seropositivity), 4.2% developed an anamnestic or secondary anti-HBs response, and 22.9% did not develop an anti-HBs response. Increasing the cutoff point of the ELISA or reconfirmation with radioimmunoassay (RIA) reduced only a minor half of the false positives. This low specificity of anti-HBc ELISA/RIA, together with the high rate of anti-HBs response to hepatitis B vaccine, indicates that subjects with isolated anti-HBc seropositivity should be included in vaccination programs.

Adolescent↗

PubMed1991

Hepatitis A and B infections in transfusion-dependent thalassaemia from endemic areas.

The aim of this study was to determine the prevalence of previous hepatitis A virus (HAV) and B virus (HBV) infection which is in 64 transfusion-dependent (TD) patients with thalassaemia including 26 patients who were transfused before blood donors were screened for HBV. Serial blood samples taken from these 64 patients and 10 non-TD beta-thalassaemia intermedia patients during a 3 year period, were tested for antibody to HAV (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to core antigen (anti-HBc) and when indicated, antibody to Delta virus (anti-Delta) and HBV DNA. Liver function tests were performed also. Similar tests were conducted on 50 donor blood units. None of the 64 TD patients had evidence of past HAV infection, but 50% of blood donors had evidence of past infection (P less than 0.001). Only 2 brothers and their mother were positive for HBsAg, and 38 patients (59.4%) had persisting HBV antibodies compared with 26% of blood donors (P less than 0.001). Our TD thalassaemic patients acquired passive immunity from donor plasma, which protected them against HAV and possibly modified the outcome of HBV infection.

Adolescent↗

PubMed1990

The hemodynamics and clinical effects of labetalol in hypotensive anesthesia.

Labetalol is a relatively new and unique hypotensive agent that has both alpha- and beta-adrenoceptor blocking properties. 12 patients in fit physical condition who underwent elective oral surgery were subject to hypotensive anesthesia with labetalol to assess the hemodynamic aspects and clinical effects of the drug. All of them had their anesthesia maintained with halothane and N2O in 50% O2 supplemented by fentanyl and vecuronium. Initiation of deliberate hypotension was made with intravenous bolus of labetalol at 0.5 mg/kg and the ideal level of mean arterial pressure at 55 +/- 5 mm Hg was maintained with adjustment of the concentration of halothane. At the termination of deliberate hypotension, the blood pressure was recuperated to the baseline level by lowering the concentration of halothane and administration of 0.5-0.6 mg intravenous atropine. Our results showed that the total dose of labetalol used was 44 +/- 13 mg and blood loss amounted to 354 +/- 136 ml. Important changes of hemodynamic parameters before and after labetalol included the fall of mean BP, HR, mean PAP, CI, LVSWI, SVRI, PVRI and O2 delivery and the increasing of O2 extraction. As to CVP, PCWP, SVI, O2 consumption and shunting the alterations were minimal. Blood gas analysis showed that, save a slight fall of pH indicating mild metabolic acidosis, the PaO2 and PaCO2 remained unchanged following the use of labetalol. Labetalol-induced hypotension could be effectively reversed by using of atropine as shown in our study and all the patients recovered uneventfully from hypotensive anesthesia. They were entirely free from any complication or sequela relevant to the deliberate hypotension after one year's follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

Direct and indirect fluorescent-antibody staining techniques using commercial monoclonal antibodies for detection of respiratory syncytial virus.

A comparison was made between direct and indirect fluorescent-antibody staining techniques using commercial monoclonal antibodies for detection of respiratory syncytial virus in respiratory secretions. Overall agreement between the two tests was 94%. Using virus isolation as the reference method, the indirect test had a higher sensitivity but a similar specificity when compared with the direct test. The slight delay in reporting using the indirect technique is not clinically significant and is offset by the possibility of convenient combination of the technique with indirect fluorescent-antibodies for detection of other respiratory viruses in respiratory secretions.

Antibodies, Monoclonal↗