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Biomedical subjects

C C Liu

Publications and source records attributed to C C Liu.

At least 73 records · Page 4Linked to original sources
PubMed1999

Molecular typing of Vibrio parahaemolyticus isolates, obtained from patients involved in food poisoning outbreaks in Taiwan, by random amplified polymorphic DNA analysis.

Vibrio parahaemolyticus is one of the most important food-borne pathogens in Taiwan, Japan, and other countries with long coastlines. This paper reports on the development of a new random amplified polymorphic DNA (RAPD) method for the molecular typing of this pathogen. The 10-mer primer 284 (5'-CAG GCG CAC A-3') was selected to generate polymorphic amplification profiles of the genomic DNA at an annealing temperature of 38 degrees C. A total of 308 clinical isolates of V. parahaemolyticus collected during food poisoning outbreaks in Taiwan, mostly occurring between 1993 and 1995, plus 11 environmental and clinical reference strains were analyzed by this RAPD method. A total of 41 polymorphic RAPD patterns were recognized, and these patterns were arbitrarily grouped into 16 types (A to P). Types A, B, C, D, and E were the major types, and subtypes C3, C5, E1, B1, D2, and A2 were the major patterns. The major types were phylogenetically more closely related to each other than to any of the minor types.

DNA, Bacterial↗
PubMed1999

Basic fibroblast growth factor in experimental and clinical bacterial meningitis.

Basic fibroblast growth factor (bFGF), a neurotrophic factor in the CNS, is expressed at high levels in response to seizures or strokes. We examined the expression of bFGF during experimental bacterial meningitis and the levels of bFGF in the cerebrospinal fluid (CSF) of children with bacterial meningitis. For the experimental study, a mouse model of meningitis was established by intracranial injection of Streptococcus pneumoniae. Twenty-four hours after induced meningitis, the brains were sectioned and stained immunohistochemically for bFGF. Neutrophils and macrophages infiltrating the leptomeninges and the ventricles exhibited strong bFGF immunoreactivity. The neurons in the areas adjacent to the inflamed ventricles also showed enhanced bFGF expression. For the clinical study, we used an enzyme immunoassay to measure bFGF in CSF in 18 children with bacterial meningitis, 12 with aseptic meningitis, and 18 controls. The CSF levels of bFGF were twice as high in children with bacterial meningitis (medians 6.75-7.21 pg/mL) compared with those who had aseptic meningitis (2.9 pg/mL) or in control subjects (2.65 pg/mL, p < 0.0001, respectively). In patients with bacterial meningitis who survived, CSF bFGF decreased significantly after 24-50 h of antibiotic therapy (p < 0.0005). Patients who developed major sequelae or died had much higher levels of CSF bFGF than those without (134.9 pg/mL versus 7.38 pg/mL, p < 0.05). These findings of enhanced immunoreactivity of bFGF in experimental bacterial meningitis and an association of CSF levels of bFGF with disease severity in childhood bacterial meningitis suggest a biologic role for this neurotrophic factor in the pathophysiology of bacterial meningitis.

Animals↗
PubMed1999

Staphylococcus capitis bacteremia of very low birth weight premature infants at neonatal intensive care units: clinical significance and antimicrobial susceptibility.

Coagulase-negative staphylococci (CNS) are frequently isolated from blood cultures in critically ill neonates. However, Staphylococcus capitis is rarely reported as a pathogen in human beings. From January, 1995 to December, 1997 at a tertiary care neonatal intensive care unit (NICU), a total of 147 (62%) CNS isolates were detected from 236 positive blood cultures, including 27 isolates of S. capitis. Among the S. capitis bacteremia, 17 isolates were judged to be infections as opposed to 10 of the noninfection cultures. The occurrence of S. capitis infection was correlated with long hospital stay (52 +/- 17.6 days vs. 28 +/- 18.5 days, p=0.003) and total parenteral nutrition administration (46 +/- 17.4 days vs. 22 +/- 19.1 days, p=0.006). Apnea, bradycardia, temperature instability and poor activity were the predominant clinical features. Among the 17 episodes of bacteremia, one patient had complicated septic meningitis. There is no statistical significance between S. capitis infection and the duration of a central venous catheter placement (37 +/- 17.5 days vs. 26 +/- 19.5 days, p=0.165). No catheter related infection was proven. Removal of a percutaneous central venous catheter routinely in patients with S. capitis bacteremia is not recommended. All the patients survived after antibiotic treatment. The prevalence rate of multiple resistant S. capitis was 94%. All isolates were resistant to oxacillin, erythromycin and clindamycin but susceptible to ampicillin/sulbactam, vancomycin and teicoplanin. Empiric therapy for S. capitis infection in NICU with ampicillin/sulbactam is therefore recommended. It is important to detect S. capitis which has a high degree of antibiotic resistance in order to treat the patient correctly. S. capitis should be included as etiology and the possibility of nosocomial outbreak in very low birth weight (VLBW) premature infants at NICU.

Bacteremia↗
PubMed1998

Steroid-inhibition of [3H]gamma-hydroxybutyric acid (GHB) binding in thalamic relay nuclei increases during absence seizures.

gamma-Hydroxybutyric acid (GHB), a naturally occurring analog of GABA, induces absence-like seizures in rats. We characterized the interaction of 3alpha-hydroxy steroids, alphaxalone and tetrahydrodeoxycorticosterone (which are potent modulators of GABAA receptors) with GHB binding sites in rat brain cortical membranes. The steroids inhibited [3H]GHB binding in a dose-dependent fashion (IC50 approximately 1 microM). Neither bicuculline nor GABA altered the dose-response of steroids in the [3H]GHB assay, suggesting that there was no GABAA component involved in the steroid-inhibition of [3H]GHB binding. Also, non 3alpha-hydroxy steroids were inactive in displacing [3H]GHB. Because GHB-induced absence seizures evolve most readily from layers I-IV of frontoparietal cortex and thalamic relay nuclei, we determined if the interaction of steroids with GHB binding sites in layers I-IV of frontoparietal cortex and thalamic relay nuclei was altered during GHB-induced absence seizures. We found that during GHB-seizures steroid-inhibition of [3H]GHB binding was increased selectively in thalamic relay nuclei but not in the layers I-IV of frontoparietal cortex or any other brain regions tested. This increase in steroid-inhibition of [3H]GHB binding in thalamus was apparent about 30 min after the onset of seizures, but not at the seizure-onset. As the seizures dissipated, the IC50 values for steroids rose to the pre-seizure level. These data suggest that the enhancement in steroid-inhibition of [3H]GHB binding in thalamic relay nuclei observed during GHB-seizures was caused by absence seizures.

Anesthetics↗
PubMed1998

Properties of exgS, a gene for a major subunit of the Clostridium cellulovorans cellulosome.

The nucleotide sequence of P70, one of the three major subunits of the Clostridium cellulovorans cellulosome, has been determined. The gene designated as exgS (Genbank Accession No. U34793) consists of 2112 bp and encodes a protein containing 703 amino acids with a molecular mass of 77.7 kDa. ExgS has a putative signal peptide sequence of 32 amino acids. The N-terminal region is separated from the C-terminal region by a short-Pro-Thr-Pro linker. The C-terminal region of ExgS contains a duplicated sequence (DS), each sequence consisting of 22 amino acids. exgS, located 67 bp downstream of cbpA in the chromosome, is immediately upstream of a gene encoding a family 9 type endoglucanase that we have designated as EngH. This gene cluster to date consists of regA-cbpA-exgS-engH. Recombinant ExgS (rExgS) containing no signal peptide was expressed in E. coli. The rExgS actively digested several forms of cellulose, including Avicel, Sigmacell101, crystalline cellulose, and xylan, but not carboxymethyl cellulose (CMC). Cellotetraose was the smallest oligosaccharide substrate for rExgS. The enzymatic studies indicated that ExgS was an exoglucanase and had some properties similar to that of CelS from C. thermocellum and CelF from C.cellulolyticum. An exoglucanase has now been found to be a component of the C. cellulovorans cellulosome as well as the previously reported endoglucanases.

Amino Acid Sequence↗
PubMed1998

Cellulosome and noncellulosomal cellulases of Clostridium cellulovorans.

This paper reviews the properties of the cellulosome and noncellulosome cellulases produced by Clostridium cellulovorans, an anaerobic, mesophilic, spore-forming microorganism that produces copious amounts of cellulase. The three major subunits of the cellulosome, CbpA, exoglucanase S (ExgS), and P100, are described, as well as the properties of the functional domains of CbpA. The properties of two noncellulosomal endoglucanases, EngD and EngF, are compared. The functions of the cellulose-binding domain (CBD) of CbpA indicate its potential uses in biotechnology.

Amino Acid Sequence↗
PubMed1998

High rates of antimicrobial resistance among clinical isolates of nontyphoidal Salmonella in Taiwan.

To assess trends in antimicrobial-resistant Salmonella infections from 1989 to 1996 in southern Taiwan, the minimum inhibitory concentrations (MICs) of 14 antibiotics or antibiotic combinations were determined by the agar dilution method for 297 clinical isolates of nontyphoidal Salmonella. The rates of resistance to ampicillin, chloramphenicol, and tetracycline were 65, 67, and 78%, respectively. Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) increased from 25% in 1989-1992 to 35% in 1993-1996 (P=0.057). For new quinolones and extended-spectrum cephalosporins, no resistant strains were encountered. Multiple resistance to more than five antimicrobial drugs doubled from 10.6% in 1989-1992 to 19.7% in 1993-1996. Multiply resistant salmonellae were isolated more commonly from blood samples than from feces (30% vs. 14%, P<0.05). In Taiwan, ampicillin, chloramphenicol, and even TMP-SMX are no longer the drugs of choice for treatment of serious nontyphoidal Salmonella infections. Extended-spectrum cephalosporins are now the preferred drugs in Taiwan for treatment of invasive Salmonella infections in children.

Anti-Bacterial Agents↗
PubMed1998

Fatal coxsackievirus B infection in early infancy characterized by fulminant hepatitis.

OBJECTIVES: to clarify the major features of fatal coxsackievirus B infection characterized by fulminant hepatitis in early infancy. METHODS: clinical manifestations and laboratory investigations concerning five consecutive young infants with overwhelming coxsackievirus B fulminant hepatitis between 1994 and 1997 were retrospectively reviewed. Aetiological diagnosis was made by viral cultures and confirmed by a neutralization test with a type-specific antiserum. RESULTS: all five had a deteriorating clinical course of severe hepatitis complicated by disseminated intravascular coagulopathy (DIC). Coxsackievirus B1 infection was established in four patients and coxsackievirus B3 in one. The pathological findings of the two cases illustrated extensive hepatocellular necrosis. Fulminant hepatitis can occur as a leading presentation of disseminated coxsackievirus B infections and dominant the clinical features in neonates and young infants. CONCLUSIONS: the liver was the target organ of fatal coxsackievirus B infection in our patients. Hepatic involvement progressed rapidly to jaundice and coagulopathy, and was considered to be indicative of poor prognosis. Coxsackievirus B hepatitis may be serious in early infancy.

Coxsackievirus Infections↗
PubMed1998

Effects of an educational program on parents with febrile convulsive children.

The purpose of this study was to characterize the effects of an educational program on knowledge, attitude, concern, and first-aid measures among parents with febrile convulsive children. All parents completed a pretest questionnaire 3 weeks before the meeting. The parents were assigned randomly into experimental (n = 65) and control (n = 64) groups on the day they attended the program. The control group completed the identical questionnaire (posttest) before the program, whereas the experimental group completed the same posttest after the program. In pretest, most parents considered electroencephalogram or computed tomography necessary in evaluating their children, suggested that immunization be postponed, and rated the risk of subsequent epilepsy as high for their children. Most of them favored frequent body temperature measurement, were very anxious about further febrile convulsion episodes during the night, and were fever phobic. After education, although only a slight change in fever anxiety was found, the experimental group showed significant improvement in knowledge, attitude, concerns, and anticipatory practice of febrile convulsion compared with the control group. In conclusion the parents' poor knowledge, negative attitudes, anxiety, and inadequate first-aid measures toward febrile convulsion can be effectively improved by an educational intervention program.

Analysis of Variance↗
PubMed1998

Risk factors analysis for early fatality in children with acute bacterial meningitis.

To identify the cause of early fatality and to delineate the clinical findings on admission associated with this early fatality, a retrospective study of 101 children with bacterial meningitis was performed in southern Taiwan. Risk factors for early fatality are compared between patients with and without acute death in the first 3 days after admission. The overall patient fatality is 27%. Eighty-five percent of them (23 patients) occur at an average of 16.5 hours after admission despite proper antibiotic treatment. The causes of early death are predominantly hemodynamic in 14 patients (61%) and predominantly neurologic in nine (39%). Analysis of clinical parameters available on admission indicated a significant risk of early death in patients who have tachycardia, tachypnea, hypothermia, poor skin perfusion, metabolic acidosis, leukopenia, thrombocytopenia, low cerebrospinal fluid leukocyte count, and high cerebrospinal fluid lactate level. Multivariate analysis demonstrates that metabolic acidosis, poor skin perfusion, and low cerebrospinal fluid leukocyte count are independently and significantly associated with early fatality. In conclusion, two thirds of early fatalities in children with bacterial meningitis are the result of septic shock. Close surveillance for signs of septic shock, as well as of brain herniation should be continued, especially within 3 days after antibiotic treatment.

Acute Disease↗
PubMed1998

Measurement of equilibrium factor and unattached fraction of radon progeny in Kaohsiung, Taiwan.

To reasonably estimate the population dose from radon, equilibrium factor, Fp, and unattached fraction, fp, of radon progeny are important parameters. A Lucas cell and a working level monitor was used for most Fp measurement. The unattached fraction was measured by SARAD EQF3020. A detached house was chosen to measure the Fp in different rooms. The Fp value depended mainly on the ventilation rate and surface to volume ratio of the rooms. Fp and fp were measured in bedrooms of 14 other dwellings. Two hospitals were also chosen for measurement of Fp in the working place using rooms located in the basement. The average Fp for dwellings was about 0.5 and the average unattached fraction was about 0.055. The radon levels in the hospitals were higher than those in the dwellings but the equilibrium factors in the hospital were very low (about 0.06). The low Fp was attributed to the use of a dehumidifier in the hospitals. Dehumidifiers are popular for reducing fungi problem induced by the high humidity in Taiwan.

Air Pollution, Indoor↗
PubMed1998

The resolvase encoded by Xanthomonas campestris transposable element ISXc5 constitutes a new subfamily closely related to DNA invertases.

BACKGROUND: Conservative site-specific recombination is responsible for the resolution of cointegrates which result during the transposition of class II transposable elements. Resolution is catalysed by a transposon-encoded recombinase, resolvase, that belongs to a large family of recombinases, including DNA invertases. Resolvases and the related invertases are likely to employ similar reaction mechanisms during recombination. There are important differences, however. Resolvases require two accessory DNA binding sites within each of the two directly repeated recombination sites. Invertases instead need a host factor, Fis, and an enhancer type DNA sequence, in addition to two inversely orientated recombination sites. RESULTS: The resolvase encoded by transposable element ISXc5 from the gram-negative phytopathogen Xanthomonas campestris shows two features which distinguish it from other known resolvases. First, it is more closely phylogenetically related to invertases than other resolvases. In particular, two functionally important regions seem highly conserved between this resolvase and members of the invertase subfamily. Second, the enzyme exhibits a large extension of its carboxy-terminal domain with unknown function. We purified ISXc5 resolvase and analysed its resolution reaction in vitro. Our biochemical and DNA topological analysis reveals that critical features of resolution are similar, if not identical, to that carried out by gammadelta resolvase. However, despite its apparent similarity to invertases, we were unable to detect recombination on standard substrates for DNA inversion, in either the presence or absence of Fis. CONCLUSIONS: ISXc5 resolvase employs a reaction mechanism which is common to members of the resolvase family. Its position near the evolutionary borderline to invertases and its high degree of identity within two functionally important regions with members of the DNA invertase subfamily suggest that only a few replacements of critical residues may suffice to convert this resolvase into a functional, possibly Fis-dependent invertase.

Amino Acid Sequence↗
PubMed1998

Central nervous system candidiasis in very low-birth-weight premature neonates and infants: US characteristics and histopathologic and MR imaging correlates in five patients.

PURPOSE: To analyze the high-resolution (i.e., 5.0- or 7.5-MHz) ultrasonographic (US) imaging characteristics of central nervous system (CNS) candidiasis and their histopathologic and magnetic resonance (MR) imaging correlates in very low-birth-weight (VLBW) premature neonates and infants with systemic candidiasis. MATERIALS AND METHODS: The US images obtained in one VLBW neonate (age, 24 days; weight, 846 g) and four VLBW infants (age range, 36-161 days; weight range, 800-1, 360 g) with proved CNS candidiasis complicating systemic candidiasis and the clinical (n = 5), histopathologic (n = 3), and MR imaging (n = 2) correlates were retrospectively reviewed. RESULTS: The cranial US findings consisted of parenchymal abnormalities in four and ventricular lesions in three patients. The most common findings were multiple echogenic, rim-like microabscesses (four patients) scattered in the subcortical, periventricular, and basal ganglial areas. Confluent macroabscess formation, seen as echogenic mass-like lesions with hypoechoic centers in the periventricular regions and/or thalami, was noted on the US images obtained in two patients. The ventricles showed dilatation in two, increased ependymal echogenicity in three, the presence of intraventricular echogenic septa in two, and a lumpy choroid plexus or the presence of debris in two patients. US findings correlated well with MR imaging and autopsy findings. The histopathologic changes in the posterior fossa were well demonstrated on MR images but not demonstrated on 5.0- or 7.5-MHz US images. CONCLUSION: CNS candidiasis in VLBW neonates and infants has characteristic US features that may help in the early diagnosis of CNS involvement in systemic candidiasis.

Autopsy↗
PubMed1998

Group B streptococcal infections in children: the changing spectrum of infections in infants.

During a 9-year period from January 1988 to December 1996, 36 patients less than 18 years of age with Lancefield group B streptococcal infections were seen in the National Cheng Kung University Hospital. Among 33 infants with invasive group B streptococcal infections, 3 (9%) were early onset disease (EOD), 27 (82%) late onset disease (LOD) and 3 (9%) onset beyond the third month of life. All cases of EOD were detected during the first day of life and 2 of them were premature births. In the infants with LOD, a high incidence of meningitis occurred (78%). The most common clinical presentation in group B streptococcal infections was fever (81%), followed by irritable crying (42%) and poor feeding (39%). Seizure was noted in 57% of meningitis cases. Obstetric and neonatal risk factors were compared between EOD and LOD, with prematurity and low birth weight significantly (P=0.01) more common among infants with EOD compared with LOD. Of the strains tested, the sensitivity to penicillin, ampicillin and erythromycin were 83%, 74%, and 75%, respectively. All strains were resistant to tetracycline and gentamicin. There were 2 case fatalities (6%) and 6 (17%) had major neurologic sequelae. These data provide that the vast majority of EOD are recognized on the first day of life and prematurity is an important risk factor. In comparison to the previous report in Taiwan, a changing spectrum of GBS infections in infants occurs during the study period. The observed incidence of EOD is decreased and meningitis is still predominantly in LOD. It is suggested early recognition and aggressive therapy have resulted in a much lower mortality rate than previously reported.

Adolescent↗
PubMed1998

Lymph node metastasis in squamous cell carcinoma of the intrathoracic esophagus.

BACKGROUND: In esophageal carcinoma lymph node metastasis is one of the most important factors of prognosis. This prospective study evaluated the incidence and extent of lymph node metastasis, and assessed the relationship between the depth of tumor invasion and lymph node metastasis in esophageal carcinoma. METHODS: Between 1985 and 1996, tissue samples from 112 patients undergoing radical esophagectomy and gastric substitution for squamous cell carcinoma of the intrathoracic esophagus were collected. Patients with distant organ metastasis were excluded. All specimens were evaluated and sent for histopathologic examination. RESULTS: In 108 men and four women with a mean age of 63.1 years, the average number of dissected lymph nodes in one surgical procedure, was 30 per person. The most commonly involved nodes were the periesophageal (42.9%) and the perigastric (42.9%) nodes, followed by the recurrent laryngeal nerve (23.8%) and thoracic paratracheal (22.2%) nodes. For tumors in the upper third of the esophagus, the most frequently involved nodal groups were the periesophageal (28.6%) and the paratracheal (28.6%) nodes, followed by the recurrent laryngeal nerve (21.4%) the deep cervical (21.4%), and the perigastric (21.4%) nodes. For tumors in the middle third of the esophagus, the periesophageal nodes (27.3%) were most commonly involved, followed by the perigastric (18.2%) and the subcarina (10.6%) nodes. For tumors in the lower third of the esophagus, the perigastric lymph nodes (37.5%) were the most common nodal metastatic site, followed by the celiac (18.8%) and the recurrent laryngeal nerve (18.2%) nodes. Depth of tumor invasion was also found to correlate significantly with lymph node metastasis (p = 0.0015). CONCLUSIONS: Wide lymph node metastasis between the neck and the upper abdomen occurs frequently in squamous cell carcinoma of the esophagus. For potentially curable esophageal carcinomas, en-bloc esophagectomy with complete locoregional lymph node dissection may provide favorable local control of the lesion and more accurate tumor staging.

Adult↗