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Biomedical subjects

K W Yu

Publications and source records attributed to K W Yu.

At least 55 records · Page 3Linked to original sources
PubMed2000

Isolation of Aeromonas hydrophila in children with diarrhea.

Aeromonas species are gram-negative bacilli that lead to a wide spectrum of infectious diseases in human. In the present study, these bacilli were reviewed to assess their significance as enteric pathogens in this area. During the years of 1994 to 1998, the clinical microbiology laboratory received 2150 stool specimens of children with diarrhea. Medical charts of patients who had positive culture for Aeromonas hydrophila were reviewed. A. hydrophila were isolated from 50 (2.3%) of 2150 children with diarrhea. Most patients were outpatients with ages ranging from 5 months to 16 years old (mean age 3.5 years). The male to female ratio was 0.85:1. All patients suffered from watery or loose diarrhea, some with blood-tinged stool. Whether or not they received medication, all patients had uneventful recoveries. The results of antibiotic susceptibility testing revealed that all strains were not susceptible to ampicillin. In summary, A. hydrophila may be considered as a causative agent of gastrointestinal illness in children.

Adolescent↗
PubMed1999

Mature teratoma with secondary infection: case report.

Mature teratoma (dermoid cyst) is a common disorder in women of reproductive age. Sometimes the tumor is complicated by torsion, rupture, and malignant change. However, it rarely presents with fever. We present a 38-year-old woman with an intermittent fever for 30 days, who received occasional medical treatment without improvement. She was to our clinic for evaluation and treatment; however, fever persisted for three days without clinical improvement. No definite infection source could be identified except the presence of a huge pelvic tumor. The patient underwent exploratory laparotomy and an ovarian dermoid cyst with infection was noted. Pathology review revealed mature teratoma with superimposed infection by Escherichia coli. Fever impressively subsided on the fifth postoperative day. Although the majority of patients suffering from fever initially search for medical treatment at primary clinics, rare conditions such as persistent fever should be consulted by specialists to make differential diagnosis. Mature teratoma is rarely superimposed by infection and rarely causes fever. Furthermore, the possibility of fever caused by tubo-ovarian abscess (TOA) is often missed in patients with history of tubal ligation since there is a lower incidence of TOA in these unique patients. However, based on this case report, we should be alert whenever long-term fever is noted. Prompt surgical treatment for extirpation and an appropriate antibiotic treatment would be the choice of treatment in such cases.

Adult↗
PubMed1998

Intestinal immune system modulating polysaccharides from rhizomes of Atractylodes lancea.

Hot water extract (ALR-0) of rhizomes of Atractylodes lanceo DC. was fractionated into MeOH-soluble fraction (ALR-1), supernatant fraction of EtOH precipitation (ALR-3 + 4), and crude polysaccharide fraction (ALR-5). Among these fractions, only ALR-5 showed potent stimulating activity for proliferation of bone marrow cells mediated by Peyer's patch cells. ALR-5 gave three potently active carbohydrate-rich fractions (ALR-5IIa, 5IIb, and 5IIc) by anion-exchange chromatography on DEAE-Sepharose CL-6B, and three active polysaccharides (ALR-5IIa-1-1, ALR-5IIb-2-2, and ALR-5IIc-3-1) were further purified from the respective fractions. The order of activity was revealed to be ALR-5IIb-2-2 > or = ALR-5IIa-1-1 > ALR-5IIc-3-1, ALR-5IIa-1-1, 5IIb-2-2, and 5IIc-3-1 each was eluted as a single peak on HPLC and their molecular weights were estimated to be 74,000, 3,100, 16,000, respectively. ALR-5IIa-1-1 consisted mainly of Ara and Gal (molar ratio; 0.6: 1.0) in addition to a trace amount of uronic acid whereas ALR-5IIb-2-2 and ALR-5IIc-3-1 mainly comprised Ara, Gal, GlcA, and GalA (molar ratio; 0.2: 1.0: 0.2: 0.8, and 0.5: 1.0: 0.7: 1.5, respectively). Methylation analysis indicated that ALR-5IIa-1-1 consisted mainly of terminal Araf, 4- or 5-linked Ara, 3.4- or 3.5-branched Ara, and 3-linked, 4-linked, and 3,6-branched Gal. ALR-5IIb-2-2 and ALR-5IIc-3-1 were composed mainly of terminal Araf, 4- or 5-linked Ara, 4-linked Gal, 4-linked GalA, and terminal GlcA. In addition, ALR-5IIb-2-2 mainly comprised 4-linked Xyl whereas ALR-5IIc-3-1 consisted mainly of 2,4-branched Rha. Single radial gel diffusion indicated that ALR-5IIa-1-1 showed a strong reactivity with beta-glucosyl-Yariv antigen, whereas ALR-5IIb-2-2 and ALR-5IIc-3-1 did not show the reactivity with the antigen. Treatments of ALR-5IIa with NalO4, NaClO2 and pronase did not reduce the stimulating activity for Peyer's patch cells, however combination of exo-alpha-L-arabinofuranosidase and exo-beta-D-(1-->3)-galactanase digestions of ALR-5IIa-1-1 significantly decreased its activity.

Adjuvants, Immunologic↗
PubMed1998

Metabolism of kalopanaxsaponin B and H by human intestinal bacteria and antidiabetic activity of their metabolites.

To investigate the relationship between the intestinal bacterial metabolism of kalopanaxsaponin B and H from Kalopanax pictus (Araliaceae), and their antidiabetic effect, kalopanaxsaponin B and H were metabolized by human intestinal microflora and the antidiabetic activity of their metabolites was measured. Human intestinal microflora metabolized kalopanaxsaponin B to kalopanaxsaponin A, hederagenin 3-O-alpha-L-arabinopyranoside and hederagenin. The main metabolites of kalopanaxsaponin B were kalopanaxsaponin A and hederagenin. Kalopanaxsaponin H was metabolized to kalopanaxsaponin A and I, hederagenin 3-O-alpha-L-arabinopyranoside and hederagenin. The main metabolites of kalopanaxsaponin H were kalopanaxsaponin I and hederagenin. Among kalopanaxsaponin B, H and their metabolites, kalopanaxsaponin A showed the most potent antidiabetic activity, followed by hederagenin. However, the main components, kalopanaxsaponin B and H, in K. pictus were inactive.

Animals↗
PubMed1997

Evidence of transmission of Mycobacterium tuberculosis by random amplified polymorphic DNA (RAPD) fingerprinting in Taipei City, Taiwan.

AIMS: To determine, by strain identification of Mycobacterium tuberculosis, whether transmission has occurred between individuals or whether new strains are present. METHODS: A rapid protocol for random amplified polymorphic DNA (RAPD) analysis was developed. This protocol was applied to 64 strains of M tuberculosis that had been confirmed by culture and microbiological methods. RESULTS: There are five groups of M tuberculosis prevalent in Taipei city, Taiwan. The major types are groups I and III. Groups I and II had been prevalent until the end of last year when, according to our group analysis, they had been eradicated. However, group III was continuously present from the middle of 1995 to the middle of 1996, and group IV was present at the end of both years, which indicated that both groups were transmitted continuously. These clustered strains had demographic characteristics consistent with a finding of transmission tuberculosis. Also, there were 13 of 64 strains with unique RAPD fingerprints that were inferred to be due primarily to the reactivation of infection. In the drug resistance analysis, the major type represented included group III and part of group IV. CONCLUSIONS: Our preliminary data imply, not only that the prevalence of M tuberculosis in Taipei city is due to transmission rather than reactivation, but that drug resistance also may play a role in tuberculosis transmission.

Bacterial Typing Techniques↗
PubMed1997

Drug resistance of Mycobacterium tuberculosis isolated from patients at a medical center in Taiwan.

BACKGROUND: The advent of bactericidal drugs has had a major impact on the treatment of pulmonary tuberculosis. However, the main reasons for continuing tuberculosis prevalence are the resistance of mycobacteria and patients' lack of endurance to undergo the long-term therapy. In Taiwan, the prevalence of tuberculosis among the population of over 20-year olds has fallen from about 5.15% in 1957, to 0.88% in 1982, but then increased to 1.29% in 1987. Although it continued decreasing to 0.65% in 1994, tuberculosis remains a potential public health problem. METHODS: To determine the temporal status of drug resistance pattern among the Mycobacterium tuberculosis (M. tuberculosis) isolated at Veterans General Hospital (VGH)-Taipei, analysis was undertaken of the drug susceptibility data reported by the central Mycobacterial Laboratory, using conventional indirect methods, between 1990 to 1992. RESULTS: The susceptibility pattern of 651 M. tuberculosis isolates obtained from patients admitted to VGH-Taipei during 1990 to 1992 were analyzed; 504/651 (77.4%) were sensitive to all drugs tested. Among veterans, 23.7% (95/401) had organisms resistant to one or more antituberculosis medications: 11.5% (46/401) to a single drug; 6.2% (25/401) to two drugs; 3.2% (13/401) to three drugs, and 2.7% (11/401) to four drugs. The overall resistance rates in isolates from 250 non-veterans (142 males and 108 females) were 22.5% (32/142) in male patients and 18.5% (20/108) in female patients. Among the 142 male patients, 6.3% were resistant to a single drug; 3.5% to two; 7.7% to three and 4.9% to four drugs. Among 108 female patients, 8.3% to a single drug; 1.9% to two drugs; 2.8% to three drugs, and 5.6% to four drugs. The proportion of drug-resistance was higher in the isolates from patients with a history of previous therapy (p < 0.05). Overall, of the 401 veterans with positive cultures, 4.0% had isolates resistant to only isoniazid (INH), 14.7% had isolates resistant to at least INH, and 7.5% had isolates resistant to both INH and rifampin (RIF). Of the 142 non-veteran males, 1.4% had isolates resistant to only INH, 16.9% had isolates resistant to at least INH, and 10.6% had isolates resistant to both INH and RIF. Of the 108 non-veteran females, 3.7% had isolates resistant to only INH, 12.0% had isolates resistant to at least INH, and 8.3% had isolates resistant to both INH and RIF. Among the 401 veterans, all the drug resistant isolates were found in patients older than 45 years, and of these, 66.3% (63/95) were over 65 years, whereas age was not a significant factor for predicting resistance rates among the non-veteran patients. CONCLUSIONS: There has been a marked increase in drug-resistant tuberculosis in old aged veterans. In contrast, age was not found to be a significant factor to predict resistance rates among the non-veterans. Previously treated patients are at increased risk for drug resistance. In view of these data, it is important to identify drug susceptibility patterns accurately from all tubercle bacilli isolated from patients as this has implications for control programs as well as for patient therapy. Surveillance of drug resistance is again being considered for patients admitted to this hospital, and all physicians are urged to remain alert to drug-resistance rates and patterns in the areas where they practice.

Adult↗
PubMed1996

Increasing antibiotic resistance in clinical isolates of Aeromonas strains in Taiwan.

A total of 234 clinical isolates of Aeromonas, primarily A. hydrophila, were collected for the present study. Most were isolates from blood. By the agar dilution method, more than 90% of the Aeromonas strains were found to be susceptible to moxalactam, ceftazidime, cefepime, aztreonam, imipenem, amikacin, and fluoroquinolones, but they were more resistant to tetracycline, trimethoprim-sulfamethoxazole, some extended-spectrum cephalosporins, and aminoglycosides than strains from the United States and Australia.

Aeromonas↗
PubMed1995

Survey of antitrypanosome antibodies and studies of their specificity and autoimmunity.

As a part of investigations to characterize trypanosome infections in Taiwan, sera collected from patients admitted to Veterans General Hospital, Taipei were tested for antitrypanosome antibodies. A Trypanosoma cruzi extract-based enzyme-linked immunosorbent assay (ELISA) was used to screen and titrate 1,297 patient sera. High antitrypanosome titers were detected in 166 (12.8%) of these sera. Retitration of random samples of the high titer (HT) sera indicated a 5.4% false positive. Thirteen donors with high antitrypanosome ELISA titers were followed up. Twelve of then remained high serum titers also showed high ELISA titers against an extract of Trypanosoma conorhini. Hemocultures conducted on freshly drawn blood specimens of the 13 subjects did not provide any evidence of trypanosome infections. Electrophoretic analyses of sera from HT and low titer (LT) patients suggested differences between serum proteins of the subjects in each of the groups. Atypical reactions were observed in immunodiffusion tests performed with HT and LT sera and trypanosome extracts, while western blot analyses revealed a complex pattern of binding by both sera. The qualitative and quantitative differences in these tests suggested interactions of T. cruzi antigens with donor antibodies against unrelated antigens and/or with autoantibodies. Subsequent analyses did not indicate any association between rheumatoid factor and the reactivities of the HT sera with the parasites. However, antinuclear antibodies were detected with an indirect fluorescent antibody test (IFAT) in 50% of the HT sera and 22% of the LT sera. No differences were found between the levels of antilaminin activity of the two groups. The IFAT employing T. cruzi epimastigotes was positive for 100% of the HT sera and 22% of the LT sera. The data indicate that the high seropositivity recognized in this study is due in part to the activities of cross-reacting antibodies and/or autoantibodies in the sample population.

Adult↗
PubMed1993

Gram-negative bacillary meningitis in adults: a recent six-year experience.

Thirty-eight cases of Gram-negative bacillary meningitis in adults have been identified over the past six years at the Veterans General Hospital, Taipei. Twenty cases were associated with head trauma and/or neurosurgery, while 18 cases occurred spontaneously. The overall mortality was 58%. Within the spontaneous meningitis group, 13 cases (72%) were due to Klebsiella pneumoniae, 11 cases (61%) were associated with bacteremia and eight cases (44%) with diabetes mellitus. In spite of the administration of third-generation cephalosporins, most cases of spontaneous meningitis (15 patients, 83%) died soon after diagnosis. In contrast, the clinical course for the postneurosurgical patients was more benign. Only seven patients (35%) died during the course of therapy. Common causative agents in postneurosurgical patients included Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli. External cerebrospinal fluid drainage devices were thought to be the most important predisposing factor in Gram-negative bacillary meningitis in the postneurosurgical patients. Factors that adversely influenced the mortality of Gram-negative bacillary meningitis included the presence of bacteremia, shock, deep coma and a high initial cerebrospinal fluid leukocyte count.

Cephalosporins↗
PubMed1993

Bacteriology of necrotizing fasciitis: a review of 58 cases.

Necrotizing fasciitis is a relatively rare soft tissue infection that is characterized by rapidly widespread necrosis of the fascia and subcutaneous tissue. Fifty-eight cases were reviewed over a 5.5-year period. The majority of wound cultures were polymicrobial and single culture rate was 18.6%. The facultative organisms were most frequently recovered. The most frequently discovered bacteria were E. coli, Proteus mirabilis, Klebsiella pneumoniae, Staphylococcus aureus and group D enterococcus. The overall mortality rate was 48.3%. Early recognition, serial radical surgical debridement and strong and appropriate antibiotics were essential for survival.

Anti-Bacterial Agents↗
PubMed1992

Comparative in vitro activity and beta-lactamase stability of RU29246, the active metabolite of HR916B.

HR 916B is a new orally absorbed cephalosporin. In tests its active metabolite, RU29246, inhibited Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus pneumoniae at less than or equal to 0.12 micrograms/ml, which is similar to the antibacterial activity of cefuroxime, and was more active than cefaclor. It was also more active (MIC 2 micrograms/ml) than cefixime, cefuroxime, cefaclor and cefotaxime against staphylococci. RU29246 inhibited Escherichia coli, Klebsiella pneumoniae, Citrobacter diversus, Klebsiella oxytoca, Proteus mirabilis, Providencia stuartii and Salmonella spp. at less than or equal to 1 microgram/ml, thus being more active than cefuroxime and cefaclor, but was less active than cefixime and cefotaxime. It did not inhibit Pseudomonas aeruginosa and other Pseudomonas spp., Enterobacter spp., Serratia marcescens or Bacteroides fragilis. RU29246 was not hydrolyzed by TEM-1, Staphylococcus aureus TEM-2 or Moraxella catarrhalis beta-lactamases, but was hydrolyzed by TEM-3 and the chromosomal beta-lactamases of Proteus vulgaris and Morganella morganii. Plasmid and chromosomal beta-lactamases were inhibited by RU29246.

Cephalosporins↗
PubMed1992

Mollaret's meningitis: a case report and literature review.

Mollaret's meningitis is a rare syndrome with characteristic features. We present a case with interesting clinical course and cerebrospinal fluid studies. The patient was admitted to Veterans General Hospital-Taipei 6 times between May, 1984 and May, 1991 because of recurrent meningitis (Mollaret's meningitis). No causative etiology was identified although a series of investigations were performed, including studies of the blood and CSF, roentgenogram and nuclear scintinographs. To date, there has been no standard therapeutic modality for this disease. We use aspirin for his symptomatic control with satisfactory result though colchicine has been reported as being effective also.

Humans↗
PubMed1992

Imported kala-azar: a case report.

A 77-year-old man returned from Honan Province, mainland China, and developed intermittent fever and loss of body weight. On physical examination there was evidence of chest infection but no lymphadenopathy or hepatosplenomegaly. Laboratory data suggested anemia, thrombocytopenia and polyclonal gammopathy. The diagnosis of Leishmaniasis was finally established by bone marrow aspiration which disclosed Leishman-Donovan bodies. Unfortunately, the patient expired soon after the diagnosis was made and a partial autopsy was performed. Kala-azar is a rare disease in Taiwan. However, it should be suspected in those patients who have visited the endemic areas, even though the clinical manifestations are atypical.

Aged↗
PubMed1991

In vitro activity of sparfloxacin.

Sparfloxacin, a new fluoroquinolone, inhibited the majority of members of the family Enterobacteriaceae at less than or equal to 1 microgram/ml. It was less active than ciprofloxacin but more active than ofloxacin. Against Pseudomonas aeruginosa, it was less active than ciprofloxacin but twofold more active than ofloxacin. It inhibited Staphylococcus aureus and most Streptococcus pneumoniae and Streptococcus pyogenes isolates at 0.25 micrograms/ml, whereas ciprofloxacin and ofloxacin inhibited these isolates at 2 micrograms/ml. Bacteroides fragilis was inhibited by less than or equal to 2 micrograms/ml. Sparfloxacin was less active at an acidic pH and in the presence of Mg2+. Resistance to sparfloxacin was produced by repeated exposure, although the frequency of single-step mutants was less than 10(-9).

Anti-Infective Agents↗
PubMed1991

Characterization of a monoclonal antibody (RJ5) against the immunodominant 41-kD antigen of Candida albicans.

A 41-kD component of Candida albicans was identified to be the major antigen radioimmunoprecipitated by antibodies with increased titers in the sera of patients with invasive candidiasis. A mouse monoclonal antibody (RJ5) was generated which, by immunoblotting, showed positive reactivity to the immunoprecipitated 41-kD component. By two-dimensional gel electrophoresis and immunoblotting, MoAb RJ5 was shown to react with different isoforms of the 41-kD component with pI values from 6.1 to 6.9. Furthermore, MoAb RJ5 showed positive reactivity to cytoplasmic antigens of C. albicans by frozen section and immunoperoxidase staining. By SDS-polyacrylamide gel electrophoresis and immunoblotting, MoAb RJ5 showed no cross-reactivity to antigens of Candida tropicalis and Candida parapsilosis. The epitope of the 41-kD molecule recognized by MoAb RJ5 was susceptible to treatment of proteinase K at concentrations of greater than or equal to 5 micrograms/ml, and was relatively resistant to periodate oxidation with concentration of NaIO4 up to 20 mM. This MoAb may be useful in the purification and characterization of the immunodominant 41-kD antigen of C. albicans, and as a probe in the detection of Candida antigens in the sera of patients with invasive candidiasis.

Antibodies↗
PubMed1991

Tetanus: 20 years of clinical experience.

Tetanus remains a life-threatening disorder and its fulminating course always presents a challenge to the clinician. We retrospectively evaluated 56 patients with tetanus admitted to VGH-Taipei between 1971 and 1990. All of these patients with tetanus on admission showed typical features, with the most common initial complaints being lockjaw and dysphagia (82.6%). They were diagnosed on clinical identification rather than isolation of the causative agent. The laboratory tests were usually nonspecific and of limited value for diagnosis. Overall, 38 patients were seized with tetanus after an identified wound infection. The most common routes were puncture wound (28.3%) and abrasion wound (19.6%). The majority of patients became symptomatic within 10 days (56.5%) and the shorter interval reflected a more overwhelming course (p less than 0.05). Intravenous drug abusers and larger wounds had a poorer prognosis. The average mortality was 39.1% (18 out of 46 patients; male/female 12/6), with lack of statistical difference between sex and mortality (p greater than 0.5). The course of tetanus in the newborn and elderly was also more deadly (mortality rates of 83.3% and 55.6% respectively). Aspiration pneumonia and subsequent respiratory failure accounted for the most common cause (11 cases, 61.1%) of death. The mortality was still high (28.6%) from 1980-90 even with better supportive care and modern therapeutic equipment.

Adolescent↗
PubMed1990

Antimicrobial activity and beta-lactamase stability of BMY-28232, parent compound of an oral cephalosporin.

BMY-28232, an aminothiazolyl imino methoxy cephalosporin which is available as an orally absorbed acetoxyethyl ester, inhibited strains of methicillin-susceptible Staphylococcus aureus, hemolytic streptococci, Streptococcus pneumoniae, Escherichia coli, Klebsiella species, and many strains of Proteus and Providencia stuartii at concentrations less than 1 microgram/ml, including isolates resistant to cephalexin and cefaclor. It had activity similar to that of cefixime, but was more active against methicillin-susceptible staphylococci. BMY-28232 was a poor substrate for beta-lactamases but was destroyed by the new TEM-3 enzyme, and had less activity against Enterobacter species, Citrobacter freundii, and Proteus vulgaris isolates. Methicillin-resistant staphylococci, Pseudomonas species, enterococci, Listeria monocytogenes, Corynebacterium jeikeium, Bacteroides fragilus and some strains of Clostridium species were resistant to BMY-28232.

Bacteria↗