Search

The average number of tandem repeats of the rib gene (which encodes the Rib surface protein) in invasive group B streptococci from 29 neonates was smaller than that from 20 adults (6.8 and 8.6, respectively; P<0.05), implying a distinct contribution of immunity toward this age-related variation.

Background: Minimizing the time of anesthesia emergence can facilitate faster patient turnover in the operating rooms of a busy surgery center. According to Lin's new concept of inhalation uptake, after turning off the vaporizer under close-circuit anesthesia (CCA) with a very low fresh gas flow rate, the concentration of desflurane decreases at a slow rate. The aim of this study was to determine if earlier cessation of desflurane supply would shorten the emergence time and at the same time register the changes of desflurane concentration in the circuit after turning off the vaporizer., Methods: 30 patients were randomly assigned to two groups, i.e., the control group and the study group. In the control group, the desflurane supply was continued up till the end of the operation, while in the study group the desflurane supply was cut off prior to the suturing the skin. In the study group, data regarding the hemodynamic changes, time from turning off desflurane with high flow washout to wakefulness, and the inspired as well as the expired desflurane concentrations at the low-flow anesthetic phase were collected. The time required from high flow washout to emergence was recorded in all patients. Inter-group and intra-group data were analyzed with nonparametric 2-independent-samples Mann-Whitney test and 2 related-samples Wilcoxon signed ranks test, respectively., Results: Under CCA with similar surgical duration, the patients in the study group emerged from anesthesia significantly faster than those in the control group (5.6 +/- 1.9 min versus 8.8 +/- 2.3 min; P < 0.05), without molestation of stable hemodynamic signs. At the low-flow wash-in stage, the inspired desflurane concentrations were significantly higher than the expired ones from 0 to 2nd min; no significant difference was noted from the 3rd to 6th min, but after which the expired concentrations were significantly higher. Desflurane concentrations decreased most noticeably during the first 5 min (0.35 +/- 0.14%), and then the decrease was moderating from 6th to 10th min (0.21 +/- 0.58%) and staggered from 11th to 15th (0.14 +/- 0.06%). The mean duration of low flow wash was 25.6 +/- 11.6 min. No patient reported awareness during surgery., Conclusions: Ceasing desflurane supply earlier in CCA (250 mL/min) significantly shortens emergence time without significant hemodynamic changes.

The possibility of the release of smallpox virus into a predominantly nonimmunized population highlights the importance of understanding poxvirus biology. Poxviruses encode a conserved pathway that is required to oxidize disulfide bonds in nascent viral proteins that fold in the reducing environment of the eukaryotic host cytoplasm. We present the structure of the last enzyme of the vaccinia virus pathway, G4, which is almost identical in smallpox virus. G4 catalyzes the formation of disulfide bonds in proteins that are critical for virus maturation and host cell infection. G4 contains a thioredoxin fold and a Cys-X-X-Cys active site. In solution, G4 monomers and dimers are observed. In the crystal, G4 is found as a dimer that buries 4,500 A(2) in the interface and occludes the active site, which could protect the reactive disulfide from reduction in the cytoplasm. The structure serves as a model for drug design targeting viral disulfide bond formation.

A total of 522 Streptococcus pneumoniae invasive isolates from diverse sources were collected from January 2002 to December 2003 in Taiwan in order to understand the serotype distribution of invasive isolates in Taiwan. The most frequently isolated serotypes of S. pneumoniae were types 14 (18.4%), 23F (15.1%), 3 (13.8%), 19F (13.4%), 6B (8.2%), 9V (3.6%) and 4 (2.5%). The majority of cases were either under 5 years of age (24.1%) or older than 65 years (36.6%). Serotype distribution in adults aged over 14 years and children aged under 2 years was similar, except for that of type 3, which was more prevalent in adults. Penicillin-non-susceptible strains accounted for 67.7% of all strains and were the predominant strains of serotypes 23F, 19F, 6B and 14. Most strains were susceptible to cephem drug, 85.7% of isolates were susceptible to cefotaxime and 92.9% were susceptible to ceftriaxone. A total of 72.6% (379/522) of the isolates were resistant to at least two antibiotics. The 23-valent vaccine in the current commercial market would cover 87.2% of the serotypes and 100% of the penicillin-non-susceptible serotypes of S. pneumoniae in Taiwan. The coverage of 7- and 11-valent protein conjugate vaccines of the serotypes in children under 2 years of age would be 78.8 and 86.5%, respectively. These results will help to assess the adequacy of the vaccine formulations marketed in Taiwan.

Pertussis reemerges periodically despite high pertussis vaccination coverage in many countries. We used prn and fim3 gene sequences and pulsed-field gel electrophoresis (PFGE) to analyze the molecular epidemiology of 168 clinical isolates of Bordetella pertussis during 1993-2004, and deduced possible reasons for an outbreak in 1997 in Taiwan. In Taiwan, during 1996-1997, a shift of prn1 to prn2 was reflected in a transition of PFGE group I to group IIIa; during 2000-2001, the change from fim3A to fim3B was displayed in transition of PFGE group IIIa to group IIIb. These changes were also consistent with the two peaks of pertussis incidence in 1997 and 2000. In 1997, a larger than expected increase in the incidence of pertussis occurred and isolates were characterized by complicated pulsotypes, appearance of many new profiles and an unusual presence of prn3. Based on a high resemblance of PFGE profiles and the same virulence genes, a similar shift of circulating strains was observed in European countries as well as Taiwan; thus, the high incidence of pertussis in 1997 may be due to an international expansion of B. pertussis strains from a similar source. This study provides further elucidation of the global molecular epidemiology of B. pertussis.

We evaluated paravertebral transcutaneous electrical nerve stimulation (TENS) as a means of enhancing anesthesia during hysterectomy. Patients were randomly assigned to experimental (n = 21) and control (n = 20) groups. Anesthesia with isoflurane was performed uniformly for all patients. Paravertebral (T6 and T7) TENS (50 mA, 15 Hz, continuously) was applied in the experimental group. After 15 min of isoflurane, a lower abdominal, skin-to-adipose-tissue incision was made. Seventeen of 21 patients in the experimental group showed no arm or leg movements during the incision, compared to 8 with 20 patients in the control group (P = 0.007). TENS deserves further exploration as an adjunct technique for general anesthesia.

A novelly improved polymerase chian reaction and immunochromatography test (PCR-ICT) hybrid assay comprising traditional multiplex-nested PCR and ICT, (a lateral-flow device) was developed for direct detection of Legionella bacteria from environmental cooling tower samples. The partial 16S rDNA (specific for Legionella spp.) and dnaJ (specific for Legionella pneumophila) genes from Legionella chromosome were first specifically amplified by multiplex-nested PCR, respectively, followed by detection using ICT strip. Reading of results was based on presence or absence of the two test lines on the strips. Presence of test line 1 indicated existence of Legionella spp. specific 16S rDNA and identified Legionella spp. Presence of test line 2 further indicated existence of dnaJ and thus specifically identified L. pneumophila. In contrast, for non-Legionellae bacteria no test line formation was observed. Results of direct detection of Legionella bacteria and L. pneumophila from water tower specimens by this assay showed 100% sensitivity, and 96.6% and 100% specificity, respectively compared with traditional culture, biochemical and serological identification methods. The PCR-ICT hybrid assay does not require sophisticated equipment and was proved to be practically useful in rapid and direct Legionellae detection from environmental water samples.

Tracing the source of a legionellosis (LG) case revealed that the Legionella pneumophila (LP) strain isolated from patient's sputum shared the same serogroup (SG) and PFGE-type with 4 LP strains obtained from a spa center. With a high LP-contamination rate (81.2%, 13/16) in all of its 16 basins, this spa center was also found to have a multi-genotypic distribution among its 13 LP isolates, which can be categorized into 5 PFGE-types. Despite such a serious contamination in the spa center, which usually had ca. 100 visitors per day, this male patient, bearing LG-risk factors of long-term heavy smoking and alcoholism, was the only case identifiable after an active investigation. To explore the possible reason for this sporadic infection, all 5 PFGE-types of LP isolated were assayed for their presence of two important virulent genes (lvh and rtx A) and were identified as either less-virulent (lvh (+) , rtx A(+)) or non-virulent (lvh (-), rtx A (-)) types. The strong virulent type (lvh (+), rtx A (+)) usually seen in clinical strains elsewhere was not found here. Moreover, the LG-causative type in this infection was the only one to be classified as the less-virulent type, with the presence of lvh gene indicating its relatively more virulent potential than other 4 PFGE-types. Accordingly, mutual interaction between LP's virulent potential and patient's health-status was suggested to be the force directing the opportunistic infection of this sporadic case. This is the first spa-associated infection caused by SG 2 of LP.

P25 and P28 proteins are essential for Plasmodium parasites to infect mosquitoes and are leading candidates for a transmission-blocking malaria vaccine. The Plasmodium vivax P25 is a triangular prism that could tile the parasite surface. The residues forming the triangle are conserved in P25 and P28 from all Plasmodium species. A cocrystal structure shows that a transmission-blocking antibody uses only its heavy chain to bind Pvs25 at a vertex of the triangle.

In recent studies, antigenic divergence has been observed in Bordetella pertussis circulating isolates. We collected 80 Bordetella pertussis isolates in Taiwan from 1998 to 2004 and analyzed them using a combination of pulsed-field gel electrophoresis (PFGE) and sequencing of the ptxS1 and prn genes. The incidence of pertussis increases every 3 years, and most of the isolates prevalent since 1998 have expressed nonvaccine ptxS1A and prn2 alleles. Through PFGE analysis, all isolates could be classified into four major groups, and the incidence of these groups exhibited a correlation with the prn allele expressed by the isolates. We found that PFGE is more discriminative than gene sequencing, since it could divide the isolates expressing the prn2 allele into two groups: one group circulating from 1998 to 2001 and another group circulating from 2001 to 2004. The transition between the two groups in 2000 coincided with an outbreak of 326 cases. This research indicates that the antigenic divergence of B. pertussis circulating isolates has evolved over time in Taiwan. Such information will have implications for vaccine policy in Taiwan.

The aim of this study was to explore the epidemiological distribution of legionellosis among pneumonia patients in Taiwan. From January 2001 to December 2003, specimens (i.e., sputum, urine, and serum) from a total of 5097 patients with pneumonia or pneumonia-like disease registered at hospitals in the Taiwan area were analyzed for possible Legionella infection. Following the guideline issued by the Centers for Disease Control and Prevention (CDC) in the United States, a total of 237 pneumonia patients were diagnosed with legionellosis, with an incidence rate among pneumonia patients in this area of 4.7% (237/5097). The paired-serum antibody test was found to be the most effective detection method, followed by urine-antigen detection and the sputum culture method. Analysis of distribution showed that: (1) male and female occurrence rates were 70.9% (168/237) and 29.1% (69/237), respectively; (2) occurrence rates in different age groups, i.e., those aged between 61 and 80 years, those aged between 41 and 60, and those aged between 21 and 40 were 50.2% (119/237), 26.2% (62/237), and 12.2% (29/237), respectively; (3) autumn was the peak season for infection, followed by winter, summer, and spring, sequentially. This is the first study in Taiwan to have followed the three-method guideline issued by the CDC and it is the second report in Taiwan involving the investigation of a large series of pneumonia patients for legionellosis detection.

How to reduce the occurrence of food-borne illness has always been one issue of great importance in Taiwan's disease prevention and control efforts, and it is important to determine, from survey results, whether the pathogens in Taiwan are the same or different from those in other countries. Accordingly, data on 1171 food-borne illness outbreaks were collected from the Center for Disease Control (CDC) of the Department of Health in Taiwan. The patients and the cases were numbered according to the guidelines and definition of food poisoning given by the Department of Health in Taiwan. All rectal swabs for culture were collected from the CDC. During 1995 to 2001, 1171 outbreaks of food-borne illness, including 109,884 cases, were reported in northern Taiwan, of which 735 (62.8%) were caused by bacterial infection. Bacterial pathogens, particularly Vibrio parahaemolyticus (86.0%), Staphylococcus aureus (7.6%), and Salmonella spp. (4.9%) were the main etiologic agents. The responsible pathogens in Taiwan appeared to be quite different from those in Europe and the United States. It is important to establish a unique surveillance net of our own to prevent and control our situation of food-borne disease outbreaks effectively.

Although eradicated from nature more than two decades ago, the threat of smallpox has reemerged because of concerns over its use as a biological weapon. We present the structure of the poxvirus L1 protein, a molecule that is conserved throughout the poxvirus family and is nearly identical in vaccinia virus and in variola virus, which causes smallpox. L1 is a myristoylated envelope protein that is a potent target for neutralizing antibodies and an important component of current experimental vaccines. The L1 structure reveals a hydrophobic cavity located adjacent to its N terminus. The cavity would be capable of shielding the myristate moiety, which is essential for virion assembly. The structure of L1 is a step in the elucidation of molecular mechanisms common to all poxviruses that may stimulate the design of safer vaccines and new antipoxvirus drugs.

Background: Spinal anesthesia has been widely used in clinical setting with relatively high incidences of hypotension and bradycardia. Lowering the dosage of local anesthetics is one of the methods to mitigate the side effects. This study was to evaluate the feasibility of lowering the dosage of tetracaine in spinal anesthesia for patients undergoing anorectal surgery., Methods: Thirty patients scheduled for anorectal surgery were studied. Patients were randomly divided into experiment (n = 15, 3.0 mg of tetracaine) and control groups (n = 15, 6.0 mg of tetracaine). The extent of analgesia was assessed by loss-of-sensation to pinprick. Dermatomic level of the sensory block was evaluated and recorded every minute for 10 minutes. BP and HR were recorded at 3-min interval for the 10-min in the study period. Numeric data were statistically analyzed with Student's t-test. The categorical data were compared using the chi-square test. P-value less than 0.05 was considered statistically significant., Results: Ten min after the injection, the mean peak level of sensory block reached T12 for experiment and T9 for control groups. A noticeable difference in frequency of hypotension between two groups was found though it was not statistically significant (P = 0.08). Incidences of moderate bradycardia and severe bradycardia were similar in both groups, being 13.3% and 6.7% respectively., Conclusions: This study confirmed that lowering the dosage of tetracaine to 3.0 mg could equally provide adequate spinal anesthesia for anorectal surgery. The reduced dosage has the tendency of reducing the rate of hypotension, but apparently it does not reduce the incidence of bradycardia.

The nucleotide sequence of glycoprotein E of YL vaccine strain was cloned, sequenced and expressed in E. coli. Phylogenetic analysis of envelope (E) amino acid sequences of 18 JEVs in GenBank showed that the vaccine strain YL closer to the virulent strain HVI which is a Taiwanese isolate. We found only two amino acid mutations (K-138 and G-389) of E protein might lead viral attenuation in YL. In this study, we used pRSET vector system to construct three recombinant plasmids (pRSET/F1R1, pRSET/F2R2 and pRSET/F1R2), which encoded and expressed different or overlapping amino acid region of E protein. The antigenicity and hemagglutination activity of these recombinant proteins were examined by western blotting and hemagglutination test, respectively. Our results demonstrated that the recombinant protein of pRSET/F1R2 possesses predominant antigenicity and hemagglutination activity.

The prompt clearance of cells undergoing apoptosis is critical during embryonic development, normal tissue turnover, as well as inflammation and autoimmunity. The molecular details of the engulfment of apoptotic cells are not fully understood. ced-6 and its human homologue gulp, encode an adapter protein, whose function in engulfment is highly evolutionarily conserved; however, the upstream and downstream components of CED-6 mediated signaling are not known. Recently, ced-1 has been shown to encode a transmembrane protein on phagocytic cells, with two functional sequence motifs in its cytoplasmic tail that are important for engulfment. In this study, using a combination of biochemical approaches and yeast two-hybrid analysis, we present evidence for a physical interaction between GULP/CED-6 and one of the two motifs (NPXY motif) in the cytoplasmic tail of CED-1. The phosphotyrosine binding domain of GULP was necessary and sufficient for this interaction. Since the precise mammalian homologue of CED-1 is not known, we undertook a database search for human proteins that contain the motifs shown to be important for CED-1 function and identified CD91/LRP (low density lipoprotein receptor-related protein) as one candidate. Interestingly, recent studies have also identified CD91/LRP as a receptor involved in the phagocytosis of apoptotic cells in mammals. The GULP phosphotyrosine binding domain was able to specifically interact with one specific NPXY motif in the CD91 cytoplasmic tail. During these studies we have also identified the mouse GULP sequence. These studies suggest a physical link between CED-1 or CD91/LRP and the adapter protein CED-6/GULP during engulfment of apoptotic cells and further elucidate the pathway suggested by the genetic studies.

The inositol phosphatase SHIP binds to the FcgammaRIIB1 receptor and plays a critical role in FcgammaRIIB1-mediated inhibition of B-cell proliferation and immunoglobulin synthesis. The molecular details of SHIP function are not fully understood. While point mutations of the signature motifs in the inositol phosphatase domain abolish SHIP's ability to inhibit calcium flux in B cells, little is known about the function of the evolutionarily conserved, putative noncatalytic regions of SHIP in vivo. In this study, through a systematic mutagenesis approach, we identified the inositol phosphatase domain of SHIP between amino acids 400 and 866. Through reconstitution of a SHIP-deficient B-cell line with wild-type and mutant forms of SHIP, we demonstrate that the catalytic domain alone is not sufficient to mediate FcgammaRIIB1/SHIP-dependent inhibition of B-cell receptor signaling. Expression of a truncation mutant of SHIP that has intact phosphatase activity but lacks the last 190 amino acids showed that the noncatalytic region in the C terminus is essential for inhibitory signaling. Mutation of two tyrosines within this C-terminal region, previously identified as important in binding to Shc, showed a reduced inhibition of calcium flux. However, studies with an Shc-deficient B-cell line indicated that Shc-SHIP complex formation is not required and that other proteins that bind these tyrosines may be important in FcgammaRIIB1/SHIP-mediated calcium inhibition. Interestingly, membrane targeting of SHIP lacking the C terminus is able to restore this inhibition, suggesting a role for the C terminus in localization or stabilization of SHIP interaction at the membrane. Taken together, these data suggest that the noncatalytic carboxyl-terminal 190 amino acids of SHIP play a critical role in SHIP function in B cells and may play a similar role in several other receptor systems where SHIP functions as a negative regulator.

Human immunodeficiency virus type 1 (HIV-1) patient isolates and molecular clones were used to analyze the determinants responsible for human CD4(+) thymocyte depletion in SCID-hu mice. Non-syncytium-inducing, R5 or R3R5 HIV-1 isolates from asymptomatic infected people showed little or no human CD4(+) thymocyte depletion in SCID-hu mice, while syncytium-inducing (SI), R5X4 or R3R5X4 HIV-1 isolates from the same individuals, isolated just prior to the onset of AIDS, rapidly and efficiently eliminated CD4-bearing human thymocytes. We have mapped the ability of one SI HIV-1 isolate to eliminate CD4(+) human cells in SCID-hu mice to a region of the env gene including the three most amino-terminal variable regions (V1 to V3). We find that for all of the HIV-1 isolates that we studied, a nonlinear relationship exists between viral replication and the depletion of CD4(+) cells. This relationship can best be described mathematically with a Hill-type plot indicating that a threshold level of viral replication, at which cytopathic effects begin to be seen, exists for HIV-1 infection of thymus/liver grafts in SCID-hu mice. This threshold level is 1 copy of viral DNA for every 11 cells (95% confidence interval = 1 copy of HIV-1 per 67 cells to 1 copy per 4 cells). Furthermore, while SI viruses more frequently achieve this level of replication, replication above this threshold level correlates best with cytopathic effects in this model system. We used GHOST cells to map the coreceptor specificity and relative entry efficiency of these early- and late-stage patient isolates of HIV-1. Our studies show that coreceptor specificity and entry efficiency are critical determinants of HIV-1 pathogenesis in vivo.

Phagocytosis of apoptotic cells is a key step in the completion of programmed cell death that occurs throughout life in multicellular organisms. The molecular events involved in clearance of apoptotic cells are just beginning to be elucidated. Recently, CED-6, an adapter protein involved in engulfment has been cloned in Caenorhabditis elegans and in humans. CED-6 is composed of a phosphotyrosine-binding (PTB) domain and a proline-rich C-terminal domain with no apparent catalytic domain. Since PTB domains, originally identified in Shc, mediate intracellular signaling downstream of cell surface receptors, CED-6 has also been proposed to mediate intracellular signals leading to engulfment. In this report, we demonstrate that CED-6 dimerizes through a leucine zipper domain that is immediately adjacent to the PTB domain. Several lines of evidence based on co-immunoprecipitation studies, yeast two-hybrid assays, and gel filtration studies suggest that CED-6 exists as a dimer in vivo. Through mutational analyses, we show that the leucine zipper is necessary and sufficient for CED-6 dimerization and that this dimerization is conserved among C. elegans, rodent, and human CED-6 proteins. We propose that dimerization may have unique implications for ligand binding via CED-6 and its function during the phagocytosis of apoptotic cells.

Two hundred and thirty healthy children scheduled for receiving elective minor surgery were assigned into 4 different groups. Group I (small infant group) included 27 infants of age from 1 to 3 months (2.0 +/- 0.6 months), Group II (infant group) included 42 infants age from 3 to 12 months (7.4 +/- 2.8 months), Group III (pre-school children group) included 122 patients of age from 1 to 6 years (3.1 +/- 1.4 years). The remained 39 cases of age older than 6-years-old (8.0 +/- 1.5 years) were collected in group IV (old children group). All studied children were starved for at least 4, 6, or 8 hours in infants, pre-school children, and old children group, respectively, pre-operatively. The fasting time and fasting blood glucose levels of the 4 groups were 6.7 +/- 1.4 hours and 109.0 +/- 22.9 mg% in group I, 7.7 +/- 2.3 hours and 98.6 +/- 18.0 mg% in group II, 10.4 +/- 2.9 hours and 96.9 +/- 24.7 mg% in group III, and 12.6 +/- 2.6 hours and 95.7 +/- 20.5 mg% in group IV, respectively. No one in the 230 children had blood glucose less than 40 mg% even in 5 infants who were starved for 12 hours or more. Therefore, we concluded that preoperative starvation is well tolerated than the originally expected in the infants and children. The fasting time before anesthesia can be executed safely even though the operation schedule may not be right on time.

Twelve ASA physical status I-II patients were studied after obtaining institutional approval and informed contents. All patients were free from endocrine and metabolic disease undergoing elective low risk operation. Pethidine 1 mg/kg i.m. and benzodiazepine 0.01 mg/kg p.o. were given as premedication one hour before anesthesia. Anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1.5 mg/kg for tracheal intubation. Anesthesia was maintained with 2% isoflurane and 50% N2O in oxygen. Ventilation was controlled and adjusted to maintain an end-tidal CO2 concentration of 25-35 torr. Atracurium 0.4 mg/kg was given as muscle relaxant. Blood samples were obtained from radial arterial catheter, 15 minutes before induction of anesthesia and 5 min after anesthesia, 15 min, 30 min, 60 min during operation and 30 min after operation in postanesthesia recovery room. The results showed that there were no statistically significant changes in plasma levels of NPY and catecholamines during operation underwent isoflurane anesthetic technique. This result indicates that isoflurane anesthesia can block the plasma NPY as well as catecholamines during surgical stress.