[Efficacy and initial clinical evaluation of optical genome mapping in the diagnosis of structural variations]

To investigate the efficacy and value of optical genome mapping (OGM) in detecting chromosomal structural variations. In a clinical study about high-precision analysis of genomic structural variation for complex genetic diseases, a retrospective study was performed on the cases with karyotyping at the department of Obstetrics and Gynecology, and Endocrinology of Peking Union Medical College Hospital from January to December 2021. Ten cases with abnormal karyotype was detected by OGM. Partial cases were verified by fluorescence in situ hybridization (FISH), SNP array or CNV-seq. Results of ten cases, nine were detected with abnormality by OGM, including unbalanced chromosomal rearrangements (n=3), translocation (n=5) and paracentric inversion (n=1), and the results were in concordance with other standard assays. However, one case with breakpoint and reconnected at centromere has not been detected. In conclusion, ten samples were comprehensively analyzed by karyotyping, FISH, SNP array or CNV-seq, and OGM, and results demonstrated that optical genome mapping as a new technology can not only detect unbalanced rearrangements such as copy number variants as well as balanced translocations and inversions, but more importantly, it can refine breakpoints and orientation of duplicated segments or insertions. So it can contribute to the diagnosis of genetic diseases and prevent birth defect. However, the current technology is not yet capable of detecting breakpoints of balanced structural variations lying within unmapped regions.

A polymorphism in New Zealand inbred mouse strains that inactivates phosphatidylcholine transfer protein

New Zealand obese (NZO/HlLt) male mice develop polygenic diabetes and altered phosphatidylcholine metabolism. The gene encoding phosphatidylcholine transfer protein (PC-TP) is sited within the support interval for Nidd3, a recessive NZO-derived locus on Chromosome 11 identified by prior segregation analysis between NZO/HlLt and NON/Lt. Sequence analysis revealed that the NZO-derived PC-TP contained a non-synonymous point mutation that resulted in an Arg120His substitution, which was shared by the related NZB/BlNJ and NZW/LacJ mouse strains. Consistent with the structure-based predictions, functional studies demonstrated that Arg120His PC-TP was inactive, suggesting that this mutation contributes to the deficiencies in phosphatidylcholine metabolism observed in NZO mice.

Adverse hepatic and cardiac responses to rosiglitazone in a new mouse model of type 2 diabetes: Relation to dysregulated phosphatidylcholine metabolism

Given the heterogeneous nature of metabolic dysfunctions associated with insulin resistance and type 2 diabetes (T2D), a single pharmaceutical cannot be expected to provide complication-free therapy in all patients. Thiazolidinediones (TZD) increase insulin sensitivity, reduce blood glucose and improve cardiovascular parameters. However, in addition to increasing fat mass, TZD have the potential in certain individuals to exacerbate underlying hepatosteatosis and diabetic cardiomyopathy. Pharmacogenetics should allow patient selection to maximize therapy and minimize risk. To this end, we have combined two genetically diverse inbred strains, NON/Lt and NZO/Lt, to produce a "negative heterosis" increasing the frequency of T2D in F1 males. As in humans with T2D, treatment of diabetic and hyperlipemic F1 males with rosiglitazone (Rosi), an agonist of peroxisome proliferator-activated gamma receptor (PPARgamma), reverses these disease phenotypes. However, the hybrid genome perturbed both major pathways for phosphatidylcholine (PC) biosynthesis in the liver, and effected remarkable alterations in the composition of cardiolipin in heart mitochondria. These metabolic defects severely exacerbated an underlying hepatosteatosis and increased levels of the adipokine, plasminogen activator inhibitor-1 (PAI-1), a risk factor for cardiovascular events. This model system demonstrates how the power of mouse genetics can be used to identify the metabolic signatures of individuals who may be prone to drug side effects.

Differential endocrine responses to rosiglitazone therapy in new mouse models of type 2 diabetes

Polygenic mouse models for obesity-induced type 2 diabetes (T2D) more accurately reflect the most common manifestations of the human disease. Two inbred mouse strains (NON/Lt and NZO/HlLt) separately contributed T2D susceptibility- conferring quantitative trait loci to F1 males. Although chronic administration of rosiglitazone (Rosi) in diet (50 mg/kg) effectively suppressed F1 diabetes, hepatosteatosis was an undesired side effect. Three recombinant congenic strains (designated RCS1, -2, and -10) developed on the NON/Lt background carry variable numbers of these quantitative trait loci that elicit differential weight gain and male glucose intolerance syndromes of variable severity. We previously showed that RCS1 and -2 mice responded to chronic Rosi therapy without severe steatosis, whereas RCS10 males were moderately sensitive. In contrast, another recombinant congenic strain, RCS8, responded to Rosi therapy with the extreme hepatosteatosis observed in the F1. Longitudinal changes in multiple plasma analytes, including insulin, the adipokines leptin, resistin, and adiponectin, and plasminogen activator inhibitor-1 (PAI-1) allowed profiling of the differential Rosi responses in steatosis-exacerbated F1 and RCS8 males vs. the resistant RCS1 and RCS2 or moderately sensitive RCS10. Of these biomarkers, PAI-1 most effectively predicted adverse drug responses. Unexpectedly, mean resistin concentrations were higher in Rosi-treated RCS8 and RCS10. In summary, longitudinal profiling of multiple plasma analytes identified PAI-1 as a useful biomarker to monitor for differential pharmacogenetic responses to Rosi in these new mouse models of T2D.

Pharmacogenetic analysis of rosiglitazone-induced hepatosteatosis in new mouse models of type 2 diabetes

Although thiazolidinediones suppress hyperglycemia in diabetic (NON x NZO)F1 males, these mice exhibit unusual sensitivity to drug-induced exacerbation of an underlying hepatosteatosis only rarely experienced in human patients. To establish the pharmacogenetic basis for this sensitivity, a panel of recombinant congenic strains (RCSs) with varying degrees of obesity and diabetes was generated by fixing selected NZO HlLt alleles on the diabetes- and hepatosteatosis-resistant NON/Lt background. Four new strains in this panel were exposed to chronic rosiglitazone treatment. Only one, NONcNZO8 (designated RCS8), exhibited an F1-like hepatosteatotic response. In both the F1 and RCS8 males, this adverse effect correlated with rosiglitazone suppression of already impaired hepatic phosphatidylcholine biosynthetic enzymes in both arms of the biosynthetic pathway, the phosphatidylethanolamine methyl- transferase pathway, and the CDP-choline pathway, including choline kinase and CTP-cholinephosphate cytidylyltransferase. This adverse response was not reproduced by CL316,243, a beta3-adrenergic receptor agonist with potent antihyperlipemic effects. Genome comparison showed that RCS8 differed from the other strains in carrying NZO-derived genome on virtually all of chromosome 16 and in smaller segments on chromosomes 6, 14, and 17. Thus, these RCSs present a panel of new mouse models exhibiting differential levels of obesity and diabetes as well as different drug responses. This panel can be used to screen for treatments for type 2 diabetes and its complications.

The Collaborative Cross, a community resource for the genetic analysis of complex traits

The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease.

Production of polyclonal antibodies against territrem B and detection of territrem B in the conidia of Aspergillus terreus 23-1 by immunoelectron microscopy

Territrem B, a fungal metabolite isolated from Aspergillums terreus 23-1, is a tremorgenic mycotoxin. Immunoelectron microscopy using anti-territrem B polyclonal antibody was used to detect territrem B in the fungal body of A. terreus 23-1 at different times of culture without shaking on potato dextrose (PD) agar medium. The anti-territrem B serum was produced by immunization of rabbits with 4beta-hydroxymethyl-4beta-demethylterritrem B-sccinate bound by a linker to keyhole limpet hemocyanin. This antiserum recognized territrems and immunoelectron microscopy using this antiserum, and colloidal gold-conjugated anti-rabbit IgG antibodies showed that territrem B was localized to the fungal body of A. terreus 23-1. Territrem B was first seen in the cytoplasm of the conidia after 4 days' culture on PD agar medium. Maximal territrem B production in the conidia was seen on the 14th day of culture; however, territrem B was not formed in the hyphae at any stage of culture. These results are consistent with the previous finding that the formation of territrems is related to fungal sporulation.

Contributions of dysregulated energy metabolism to type 2 diabetes development in NZO/H1Lt mice with polygenic obesity

New Zealand Obese (NZO) male mice develop a polygenic juvenile-onset obesity and maturity-onset hyperinsulinemia and hyperglycemia (diabesity). Here we report on metabolic and molecular changes associated with the antidiabesity action of CL316,243 (CL), a beta(3)-adrenergic receptor agonist. Dietary CL treatment initiated at weaning reduced the peripubertal rise in body weight and adiposity while promoting growth without suppressing hyperphagia. The changes in adiposity, in turn, suppressed development of hyperinsulinemia, hyperleptinemia, hyperlipidemia, and hyperglycemia. These CL-induced alterations were reflected by decreased adipose tissue mass, increased expression of transcripts for uncoupling protein-1 (UCP-1), peroxisome proliferator-activated receptor alpha (PPARalpha), peroxisome proliferater-activated receptor coactivator-1 (PGC-1), and robust development of brown adipocyte function in white fat. Increased drug-mediated energy dissipation elicited a 1.5 degrees C increase in whole body temperature under conditions of increased food intake but with no change in physical activity. Indirect calorimetry of mice treated with CL showed both increased energy expenditure and a restoration of a prominent diurnal pattern in the respiratory exchange ratio suggesting improved nutrient sensing. Our data suggest that CL promotes increased energy dissipation in white and brown fat depots by augmenting thermogenesis and by metabolic re-partitioning of energy in a diabesity-protective fashion. This is the first report demonstrating the effects of dietary beta(3)-agonist in preventing the onset of diabesity in a polygenic rodent model of type 2 diabetes.

Increasing prevalence of methicillin-resistant Staphylococcus aureus causing nosocomial infections at a university hospital in Taiwan from 1986 to 2001

A rapid emergence of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection (from 26.3% in 1986 to 77% in 2001) was found. The susceptibility of 200 nonduplicate blood isolates of MRSA and 100 MRSA isolates causing refractory bacteremia to 22 antimicrobial agents disclosed that glycopeptides, quinupristin-dalfopristin, and linezolid remained the most active agents.

Evidence on the presence of secretin cells in the gastric antral and oxyntic mucosa

Secretin is released from upper small intestinal mucosa to drive pancreatic secretion of fluid and bicarbonate and inhibit gastric acid secretion. Recently, we found that, in isolated, vascularly perfused rat stomach model, the inhibition of acid secretion by pituitary adenylate cyclase activating polypeptide (PACAP) was mediated in part via local release of secretin. However, the presence of secretin-producing cells and mRNA in gastric mucosa, particularly in oxyntic mucosa, has not been established. The present study was carried out to establish the presence of secretin cells by immunohistochemical and mRNA by biochemical methods in gastric mucosa. Secretin cells were identified in antral mucosa (27.8 +/- 2.0 cells/mm(2)) and corpus (4.7 +/- 0.5 cells/mm(2)). They were distinguishable, through double immunostaining, from gastrin and somatostatin cells in the antrum and from somatostatin cells in the corpus. The results of reverse transcription (RT)-PCR and Southern blot indicated that a secretin gene transcript of 454 bp was present in the mRNA extracts of both antral and corpus mucosae. The results indicated that secretin mRNA is present in gastric mucosa. In conclusion, secretin-producing cells and mRNA are present in gastric mucosa and the locally released secretin may exert a paracrine effect to inhibit acid secretion.

Healthcare-associated outbreak due to pan-drug resistant Acinetobacter baumannii in a surgical intensive care unit

Acinetobacter baumannii is ubiquitous and has recently become one of the most important healthcare-associated (HA) pathogens in hospitals. Infection caused by this organism often leads to significant morbidity and mortality. Outbreaks of pan-drug resistant Acinetobacter baumannii (PDRAB) have rarely been reported. During a two-month period, an outbreak of PDRAB colonization and infection affecting 7 patients occurred in our surgical intensive care unit (SICU). The colonized sites were respiratory tract (N = 7) and central venous catheter (N = 2). One of the patients had a surgical wound infection. Extensive environmental contamination was identified, including sites such as bed rails, bedside tables, surface of ventilators and infusion pump, water for nasogastric feeding and ventilator rinsing and sinks. All of the isolates were analysed by pulsed-field gel electrophoresis (PFGE) and showed an identical pattern. After use of strict cohort nursing, hand hygiene environmental cleaning, and replacement of a dysfunctional high-efficiency particulate air filter (HEPA), the outbreak was controlled.

Nosocomial Exophiala jeanselmei pseudoinfection after sonography-guided aspiration of thoracic lesions

BACKGROUND AND PURPOSE

During the period from August 1994 to October 1998, a total of 19 isolates of Exophiala jeanselmei were recovered from 17 patients with various underlying thoracic diseases treated at National Taiwan University Hospital. The purpose of this study was to describe the clinical characteristics of these patients and to determine the microbiologic relatedness of the E. jeanselmei.

METHODS

Of the 19 isolates, 11 from nine patients were preserved and were identified based on their biotypes as determined by the API ID32C System, their cellular fatty acid profiles by gas-liquid chromatography, their antibiotypes to five antifungal agents by the E-test, and their random amplified polymorphic DNA (RAPD) patterns by arbitrarily primed PCR. Extensive environmental surveillance cultures and cultures from the skin of eight patients and hands of one physician were also performed.

RESULTS

One of the 17 patients had E. jeanselmei isolated from cutaneous phaeohyphomycosis (3 isolates), and the other 16 patients had isolations from pleural effusion specimens (15 isolates) or lung mass (1 isolate) following sonography-guided aspiration. The latter 16 patients had no clinical or pathologic evidence of fungal infection. Isolates (clone 1) from aspirated specimens had identical biotypes, antibiotypes, and RAPD patterns, which were different from those of the three isolates (clone 2) from the patient with a cutaneous lesion. All specimens from environmental sources, patients' skin, and the hands of the physician were negative for E. jeanselmei.

CONCLUSION

This series of patients demonstrates the difficulty in identifying the sources of a nosocomial pseudoinfection due to this slow-growing microorganism when isolated from pleural effusion specimens.

Persistent bacteraemia caused by a single clone of Burkholderia cepacia with unusual phenotype

We report a case of persistent bacteraemia caused by a single clone of Burkholderia cepacia with unusual characteristics. Six isolates of B. cepacia were recovered from a patient with acute myeloid leukaemia and chemotherapy-induced neutropenia within a 3-week period. All six isolates were initially incompletely identified as B. cepacia with the API 20NE system. The further use of cellular fatty acid analysis and PCR-restriction fragment length polymorphism of the 16S rDNA confirmed the identification. These isolates also displayed an identical but unusual antibiotype. The identical cellular fatty acid profiles and genomic typing generated by random amplified polymorphic DNA identified these isolates as derivatives of a single strain.

A hospital-acquired outbreak of methicillin-resistant Staphylococcus aureus infection initiated by a surgeon carrier

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important hospital-acquired pathogen, infection with which often leads to major morbidity and mortality. The principal mode of transmission for MRSA is transfer of the organism from a carrier or infected patient to uninfected patients by the hands or clothing of staff. From January 16 1997 to April 2 1997, five patients who had undergone open-heart surgery in a hospital located in northern Taiwan, developed surgical wound infections and mediastinitis caused by MRSA. All patients were hospitalized in two adjacent surgical intensive care units (ICUs) following their respective operations. Consequently, the hospital's infection control team commenced investigation of the outbreak. Pulsed-field gel electrophoresis (PFGE) has been shown to be a good technique for epidemiological typing. By analysing cultures taken from staff by PFGE, it was demonstrated that this outbreak was most likely to be initiated by a surgeon with MRSA carriage. After elimination of the carrier state using topical mupirocin treatment, the outbreak was controlled without further incident.

Quinupristin-dalfopristin resistance among gram-positive bacteria in Taiwan

To understand quinupristin-dalfopristin resistance among clinical isolates of gram-positive bacteria in Taiwan, where this agent is not yet available for clinical use, we evaluated 1,287 nonduplicate isolates recovered from January 1996 to December 1999 for in vitro susceptibility to quinupristin-dalfopristin and other newer antimicrobial agents. All methicillin-susceptible Staphylococcus aureus (MSSA) isolates were susceptible to quinupristin-dalfopristin. High rates of nonsusceptibility to quinupristin-dalfopristin (MICs, >/=2 microg/ml) were demonstrated for the following organisms: methicillin-resistant S. aureus (MRSA) (31%), coagulase-negative staphylococci (CoNS) (16%), Streptococcus pneumoniae (8%), viridans group streptococci (51%), vancomycin-susceptible enterococci (85%), vancomycin-resistant Enterococcus faecalis (100%), vancomycin-resistant Enterococcus faecium (66%), Leuconostoc spp. (100%), Lactobacillus spp. (50%), and Pediococcus spp. (87%). All isolates of MSSA, MRSA, S. pneumoniae, and viridans group streptococci were susceptible to vancomycin and teicoplanin. The rates of nonsusceptibility to vancomycin and teicoplanin were 5 and 7%, respectively, for CoNS, ranging from 12 and 18% for S. simulans to 0 and 0% for S. cohnii and S. auricularis. Moxifloxacin and trovafloxacin had good activities against these isolates except for ciprofloxacin-resistant vancomycin-resistant enterococci and methicillin-resistant staphylococci. In Taiwan, virginiamycin has been used in animal husbandry for more than 20 years, which may contribute to the high rates of quinupristin-dalfopristin resistance.

High protease activity of Chryseobacterium indologenes isolates associated with invasive infection

In order to understand virulence factors of Chryseobacterium indologenes isolates associated with invasive infection, enzymatic activities and cellular fatty acid profiles of 42 isolates recovered at National Taiwan University Hospital from January 1994 to December 1996 were studied. Among them, 12 blood isolates were considered as invasive and 30 (recovered from urine, sputa, infected burn wounds, and catheter tips) were noninvasive. All isolates showed strong activities of alkaline phosphatase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, and N-acetyl-beta-glucosaminidase, and had no activities for alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, and alpha-fucosidase. The activities of other enzymes were variable. Thirty-two isolates (76%) had varying degrees of protease activity. Two profiles (profiles I and II) of cellular fatty acids of the isolates were found and profile I predominated. There was no significant difference of distribution of cellular fatty acid profiles and activities of enzymes between invasive and noninvasive isolates, except protease activity which was significantly higher in invasive isolates than that in noninvasive isolates. Protease activity may play an important role in virulence on invasive infections caused by C. indologenes.

Lack of androgen receptor transcriptional activity in human keratinocytes

Since detection of androgen receptor (AR) expression in keratinocytes by immunostaining is controversial, we investigated whether keratinocytes can act as androgen target cells using transient transfection assays. Chloramphenicol acetyltransferase (CAT) assays for the endogenous AR transcriptional activity in HaCaT keratinocytes indicated that DHT (10(-9)-10(-8) M) can induce less than 1.5-fold of mouse mammary tumor virus CAT, which is quite low, compared with 38-fold induction by 10(-7) M 1,25-dihydroxyvitamin D(3) of P450cc24-CAT. Furthermore, this low DHT-mediated induction could not be enhanced by the AR co-activators, ARA70 or ARA55. Western blotting analysis indicated that HaCaT and normal keratinocytes do not express AR protein. Transfection of exogenous AR into HaCaT keratinocytes, however, could install AR transcriptional activity, suggesting that HaCaT keratinocytes have all the necessary accessory factors for AR transcription activity. In conclusion, keratinocytes are unlikely to be target cells for androgen.

Analytical systematic approximate method of a two-state dissipative system

Occupation probability and changes of the environment in a dissipative two-state system have been investigated using a systematic approximate method. This method explores the tunneling dynamics through a system state vector with manifest physical meanings and provides a deep microscopic insight into the dynamical behaviors of the system.

Application of pulsed-field gel electrophoresis to the investigation of a nosocomial outbreak of Vibrio parahaemolyticus

The method of pulsed-field gel electrophoresis (PFGE) for Vibrio parahaemolyticus was first published in 1996. Since then, its application has been seldom reported in the literature. A food poisoning outbreak due to V. parahaemolyticus occurred in five wards of a hospital was investigated using this method. Twenty-five patients were involved and all of them had eaten food supplied by the hospital. Of the 15 cases whose stools were available for culture, only four cultures yielded V. parahaemolyticus. All four isolates were serotype K6 and were indistinguishable or closely related to each other based on PFGE patterns. Two isolates from food were recovered and they presented different characterizations from the patient isolates in both serotype and PFGE pattern. Successful typing by PFGE to identify the outbreak strain and differentiate V. parahaemolyticus strains between patient and food isolates in this study suggests the usefulness of PFGE for V. parahaemolyticus, the leading cause of food poisoning in Taiwan.

[Three dimensional Finite Element Analysis of the Effects of Posts and Cores with Different Angles]

OBJECTIVE:The test is an analogue of the conditions that cast post and core can be made with different angles to get the core incline lingually or facially in clinic, so that the arrangement of the anterior teeth may be improved.METHODS:Analyse the stress distribution and concentration in the dentin of posts and cores with different angles by Ansys three dimensional finite element stress analysis method.RESULTS:The stress in root was positively related to the angles between the load and the axis of the tooth, the stress distributoin in dentin was related to the direction of the core but not related to the angles. The closer the distance from the load to cemento enamel junction,the greater the effect of the load on the stress in dentin.CONCLUSION:When the cast post and core with angle was used to rectify the facially malpositional maxillary anterior teeth, the core should not be inclined lingually excessively. It is important to assure the thickness of the facial and lingual canal wall during tooth preparing and to adjust the occlusion so that the root fracture can be avoided.

Emergence of vancomycin-resistant enterococci at a university hospital in Taiwan: persistence of multiple species and multiple clones

OBJECTIVES

To describe the epidemiology of vancomycin-resistant enterococci (VRE) in a university hospital in Taipei, Taiwan.

DESIGN

Retrospective review over a 27-month period, from March 1996 to May 1998.

SETTING

A tertiary-care teaching hospital in Taiwan.

PARTICIPANTS

Patients with VRE isolated from any body site.

METHODS

Patients were identified through hospital microbiology and infection control records. Patient charts were reviewed for clinical and epidemiology data, including age, gender, previous hospital admissions, underlying diseases, types of infection, and recent antibiotic use. VRE isolates were characterized by their typical biochemical reactions, cellular fatty acid profiles, and the presence of van genes. Antibiotypes using the E-test and randomly amplified polymorphic DNA (RAPD) patterns of these isolates were used to determine the clonality.

RESULTS

Twenty-five isolates of VRE recovered from 12 patients were identified. One patient with a perianal abscess had 12 isolates of VRE (4 Enterococcus faecalis, 7 Enterococcus faecium, and 1 Enterococcus casseliflavus) recovered from perianal lesions. Among 3 patients who were hospitalized in the same room, 1 had a community-acquired cellulitis over the left leg caused by E. faecalis, and the other 2 patients both had anal colonization with 2 isolates of E. faecalis. The other 8 patients had 1 E. faecalis isolate each from various clinical specimens. All isolates possessed vanA resistance phenotype and vanA genes. Different antibiotypes and RAPD patterns of the isolates from different patients excluded the possibility of nosocomial spread at the hospital.

CONCLUSIONS

Multiple species of VRE (E. faecalis, E. faecium, and E. casseliflavus) and multiple clones of E. faecium could colonize or infect hospitalized patients. In addition, clones of VRE can persist long-term in patients' lower gastrointestinal tracts. These results extend our knowledge of the coexistence and the persistence of multiple species and multiple clones of VRE in hospitalized patients.

Roles of testosterone in the growth of keratinocytes through bald frontal dermal papilla cells

A coculture of dermal papilla cells (DPCs) from the bald frontal scalp of stumptailed macaques with keratinocytes derived from human neonatal foreskin revealed that testosterone inhibited keratinocyte proliferation, and that the antiandrogen RU58841 abolished this response. This testosterone-induced keratinocyte growth inhibition was not observed when either type of cells was cultured alone. We also examined conditioned media from the coculture system and demonstrated the identical testosterone-induced growth inhibition on keratinocytes, and this inhibitory effect was conditioned media concentration-dependent. These results suggested that the testosterone-mediated suppression on keratinocyte proliferation might proceed through some diffusible growth mediators in conditioned media. Differential display reverse transcriptase polymerase chain reaction allowed us to isolate several genes from frontal DPCs that can be either suppressed or induced by testosterone. Supervillin, a membrane-associated, F-actin-binding protein, was identified as one of the testosterone downregulated genes in frontal DPCs. Further characterization of these testosterone-target genes may reveal the mechanism by which testosterone inhibits the growth of follicular cells in androgenetic alopecia.

Longitudinal analysis of methicillin-resistant Staphylococcus aureus isolates at a teaching hospital in Taiwan

In Taiwan, the frequency of nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has increased rapidly during the past 10 years. To investigate the epidemiology of MRSA infections, a total of 140 MRSA isolates collected at National Taiwan University Hospital from 1992 to 1996 were characterized by pulsed-field gel electrophoresis (PFGE) profiles and antibiotypes, as determined with the disk diffusion method. Among these isolates, six PFGE types (with 20 subtypes) and six antibiotypes were identified. Antibiotyping proved to be a poor method of epidemiologic analysis, because almost all of the MRSA isolates analyzed shared a very similar multidrug-resistant antibiotype. Most MRSA infections and colonizations in this hospital were due to the spread of strains belonging to three major PFGE types (A, B, and C). However, the major type changed in different years with types A, B, and C being predominant in 1992 through 1993, 1994 through 1995, and 1996, respectively. The three major PFGE types spread easily throughout the hospital wards, presumably carried by health care workers and environmental contamination. Our results demonstrate that there was a dominant strain spreading in our hospital each year and the dominant strain may shift in different years.

Transgenic mouse model of AA amyloidosis

AA amyloidosis can be induced in mice experimentally through injection of certain chemical or biological compounds. However, the usefulness of this approach is limited by its dependence on exogenous inflammatory agents that stimulate cytokines to increase the synthesis of precursor serum amyloid A (SAA) protein and the transitory nature of the pathological fibrillar deposits. We now report that transgenic mice carrying the human interleukin 6 gene under the control of the metallothionein-I promoter had markedly increased concentrations of SAA and developed amyloid in the spleen, liver, and kidneys by 3 months of age. At the time of death about 6 months later, organs obtained from these animals had extensive amyloid deposits. This disease process was apparent radiographically using small-animal computer axial tomography and magnetic resonance imaging equipment. The AA nature of the amyloid was evidenced immunohistochemically and was unequivocally established by sequence analysis of protein extracted from the fibrils. The availability of this unique in vivo experimental model of AA amyloidosis provides the means to assess the therapeutic efficacy of agents designed to reduce or prevent the fibrillar deposits found in AA and other types of amyloid-associated disease.

Dissemination of two methicillin-resistant Staphylococcus aureus clones exhibiting negative staphylase reactions in intensive care units

From December 1997 to March 1998, 25 methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibiting negative Staphylase (Oxoid Ltd., Basingstoke, England) reactions were identified from various clinical specimens from 13 patients in six intensive care units (ICUs) or in wards following a stay in an ICU at the National Taiwan University Hospital. The characteristics of these isolates have not been previously noted in other MRSA isolates from this hospital. Colonies of all these isolates were grown on Trypticase soy agar supplemented with 5% sheep blood and were nonhemolytic and unpigmented. Seven isolates, initially reported as Staphylococcus haemolyticus (5 isolates) and Staphylococcus epidermidis (2 isolates) by the routine identification scheme and with the Vitek GPI system (bioMerieux Vitek, Inc., Hazelwood, Mo.), were subsequently identified as S. aureus by positive tube coagulase tests, standard biochemical reactions, and characteristic cellular fatty acid chromatograms. The antibiotypes obtained by the E test, coagulase types, restriction fragment length polymorphism profiles of the staphylococcal coagulase gene, and random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates disclosed that two major clones disseminated in the ICUs. Clone 1 (16 isolates) was resistant to clindamycin and was susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ) and was coagulase type II. Clone 2 (eight isolates) was resistant to clindamycin and TMP-SMZ and was coagulase type IV. These two epidemic clones from ICUs are unique and underline the need for caution in identifying MRSA strains with colonial morphologies not of the typical type and with negative Staphylase reactions.

Thyroid hormone direct repeat 4 response element is a positive regulatory element for the human TR2 orphan receptor, a member of steroid receptor superfamily

We demonstrate that TR2 orphan receptor (TR2) may induce transactivation activities via an AGGTCA-like-direct-repeat-4 consensus thyroid hormone response element (DR4-TRE) system. TR2 showed a slightly greater binding affinity than thyroid hormone receptor alpha1 (TR alpha1)/retinoid X receptor alpha (RXR alpha) heterodimer with Kds 0.5 nM and 2.3 nM, respectively. These receptors, TR2 and TR alpha1/RXR alpha heterodimer, competed with each other on binding to limited amounts of DR4-TRE. TR2 canceled the suppression effect of unliganded-TR alpha1 on CAT reporter activity in a dose-dependent fashion. Estrogen receptor (ER) and 2P2 (a mutated TR2 with P box sequence of androgen receptor) failed not only to bind to DR4-TRE but also to recover this inhibitory effect of unliganded TRalpha1. However, when T3 was supplemented, estradiol-ER competed for a full CAT activity while TR2 showed an additive effect on the transcriptional activation. These results indicate that DNA binding is essential for TR2 to take action and fully functional liganded TR alpha1 may rely on common factors shared with ER but not TR2.

Outbreak of Pseudomonas fluorescens bacteremia among oncology patients

From 7 to 24 March 1997, four patients developed Pseudomonas fluorescens bacteremia at the hospital; one on the oncology ward and the other three in the chemotherapy room. These patients all had underlying malignancies and had the Port-A-Cath (Smiths Industries Medical Systems, Deltec, Inc., St. Paul, Minn.) implants. Three patients had primary bacteremia, and one had Port-A-Cath-related infection. None of these patients had received a blood transfusion before the episodes of bacteremia. All patients recovered: two received antimicrobial agents with in vitro activity against the isolates, and the other two did not have any antibiotic treatment. A total of eight blood isolates were recovered from these patients during the febrile episodes that occurred several minutes after the infusion of chemotherapeutic agents via the Port-A-Cath. These isolates were initially identified as P. fluorescens or Pseudomonas putida (four), Burkholderia (Ralstonia) pickettii (three), and a non-glucose-fermenting gram-negative bacillus (one) by routine biochemical methods and the Vitek GNI card. These isolates were later identified as P. fluorescens on the basis of the characteristic cellular fatty acid chromatogram and the results of supplemental biochemical tests. The identification of identical antibiotypes by the E test and the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates showed that the outbreak was caused by a single clone of P. fluorescens. Surveillance cultures of the possibly contaminated infusion fluids and disinfectants, which were performed 7 days after recognition of the last infected patient, failed to isolate P. fluorescens. This report of a small outbreak caused by P. fluorescens suggests that timely, accurate identification of unusual nosocomial pathogens is crucial for early initiation of an epidemiological investigation and timely control of an outbreak.

Evaluation of RU58841 as an anti-androgen in prostate PC3 cells and a topical anti-alopecia agent in the bald scalp of stumptailed macaques

The effect of androgen receptor transcriptional activation by RU58841, a nonsteroidal anti-androgen, was studied in the human prostate cancer PC3 cell line by cotransfection with wild-type androgen receptor (wt AR) and an androgen-responsive reporter (MMTV-ARE-CAT) construct. Anti-and rogens, hydroxyflutamide, and Casodex, and the antiestrogen, genistein, were studied in parallel for comparison with RU58841. The wt AR was activated only by the androgen dihydrotestosterone (DHT). Neither the anti-androgens nor antiestrogen can enhance AR transcriptional activity at 10(-11)-10(-7)M in PC3 cells. Hydroxyflutamide, RU58841, and Casodex, but not genistein, displayed competitively suppressive effects on DHT activation of wt AR. The potency of RU58841 was comparable to that of hydroxyflutamide. From this result, topical application of RU58841, which is considered to be a potential therapy for skin diseases, may induce systemic side effects. However, RU58841, on topical application, revealed a potent increase in density, thickening, and length of hair in the macaque model of androgenetic alopecia, whereas no systemic effects were detected. Together our results suggest that RU58841 may have potent antagonism to the wt AR and could be considered as a topically applied active anti-androgen for the treatment of androgen-dependent skin disorders, such as acne, androgenetic alopecia, and hirsutism.

Nosocomial infections caused by Sphingomonas paucimobilis: clinical features and microbiological characteristics

From January 1995 to September 1996, 14 isolates of Sphingomonas paucimobilis, including 11 from clinical specimens from six patients with nosocomial infection and three from environmental sources, were collected. Two of the six patients had intravascular catheter-related bacteremia and one each had bacteremic biliary tract infection, urinary tract infection, ventilator-associated pneumonia, and wound infection. The S. paucimobilis isolates were identified according to biochemical profiles established with use of the API 20NE system and Vitek GNI card and the characteristic cellular fatty acid chromatogram. Ten biotypes, 11 antibiograms (by the Etest), and 12 random amplified polymorphic DNA (RAPD) patterns (by arbitrarily primed polymerase chain reaction) were identified. The identical biotype, antibiogram, and RAPD pattern of the two isolates (one each from blood and bile) from a patient with biliary tract infection indicated the invasiveness of the organism. Two patients with intravascular catheter-related bacteremia had isolates of this organism repeatedly recovered, and these isolates had heterogeneous RAPD patterns. The present study highlights the wide distribution in hospital environments of various clones of S. paucimobilis, which may cause recurrent infections by a single strain or several episodes of infection due to two or more clones of this organism in hospitalized patients.

Identification of direct repeat 4 as a positive regulatory element for the human TR4 orphan receptor. A modulator for the thyroid hormone target genes

While the TR4 orphan receptor (TR4) is able to repress the expression of its target genes via its interaction with the direct repeat 1-hormone response element (DR1-HRE) and DR2-HRE, we now report that TR4 can also induce the transcriptional activity of the reporter gene containing a DR4-HRE via chloramphenicol acetyltransferase assay. Electrophoretic mobility shift assay and Scatchard analysis reveal a strong binding affinity (dissociation constant = 2 nM) between TR4 and DR4-HRE. The induction mediated by TR4 was detected not only in the synthetic DR4-HRE but also in some genes, such as rat alpha-myosin heavy-chain and S14 genes, containing the DR4 or DR4-like motif, which have been suggested to be the response elements for a thyroid hormone receptor. Our data also demonstrate this TR4-mediated gene induction is TR4 dose- and DR4 sequence-dependent. Together, our data suggest that DR4-HRE can be a positive regulatory element for TR4, which may be able to induce the transcriptional activity of the genes containing such positive HREs.

[Secular trends in the etiology of nosocomial infection at a teaching hospital in Taiwan, 1981-1994]

Surveillance system of nosocomial infection was established in 1980 at the National Taiwan University Hospital (NTUH). To identify pathogens and the secular trends in the etiology of nosocomial infection from 1981 to 1994, the prospective, hospital-wide nosocomial surveillance data were analysed. During this period, 22,146 pathogens causing nosocomial infections were isolated. Gram-negative aerobic bacteria remained the major pathogens, but gram-positive cocci and fungi increased rapidly in the past 14 years. When the overall pathogen distribution is examined, Pseudomonas areuginosa was the most frequently isolated pathogen, but Candida albicans and other yeasts have taken the leading position since 1993. Staphylococcus aureus and coagulase-negative staphylococci also increase significantly in recent years. When the pathogens causing infection at the 4 major sites were examined. P. aeruginosa was the pathogen most often associated with respiratory tract and surgical wound infections. In blood stream and urinary tract infections, we observed Escherichia coli was replaced by C. albicans and other yeasts as a most common isolate in these years. In addition, C. albicans and other yeasts and methicillin-resistant S. aureus (MRSA) are emerging as major nosocomial pathogens at NTUH. C. albicans and other yeast increased from 1.8% in 1981 to 14.9% in 1994 in the overall nosocomial infection. The increase was found in the blood stream (2.1% to 16.2%) and urinary tract infections (5.4% to 24.7%). Of 1,742 nosocomial S. aureus isolates, the percentage of MRSA rose from 12.5% in 1981 to 55.2% in 1994. The high percentage of MRSA was observed at 4 major anatomic sites of infection. In summary, significant shifts in the pathogens of nosocomial infection have occurred in the past 14 years at NTUH, and the distribution of nosocomial pathogens was similar to those reported in the United States in recent years.

Epidemiologic investigation of nosocomial outbreak of methicillin-resistant Staphylococcus aureus by plasmid pattern analysis

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become an important problem with increasing frequency. In order to learn if plasmid pattern analysis can be used in epidemiologic investigations of MRSA infections, the authors did plasmid extractions of 70 MRSA stock isolates using a rapid lysostaphin lysis method. All isolates carried at least one plasmid. Most of the isolates had one large plasmid of 24-28 megadaltons (Md). Many also carried one or two small plasmids. Accordingly, 12 different patterns were identified. From these background results, we applied this method to the investigation of two small nosocomial outbreaks of MRSA infection. It was found that the analysis of plasmid pattern and restriction endonuclease analysis are more discriminative than antibiograms. Strains with the same antibiograms can be different by plasmid analysis. It is concluded that the plasmid pattern with a restriction endonuclease analysis study is a reliable method for epidemiologic study of MRSA infections.

[Identification and typing of Pseudomonas pickettii during an episode of nosocomial outbreak]

From January to April 1989, Pseudomonas pickettii was isolated from clinical specimens of 24 hospitalized patients at the National Taiwan University Hospital in Taipei. The source of the organism was the 0.9% NaCl solution prepared by the hospital pharmacy. A total of 39 isolates of P. pickettii were collected, including 28 from clinical specimens and 11 from 0.9% saline and distilled water during the outbreak. These microorganisms were studied by using four methods, namely, conventional biochemical method, Vitek Auto-Microbic System (Vitek AMS), gas-liquid chromatographic analysis of cellular fatty acids composition and determination of the minimum inhibitory concentrations of 10 different antimicrobial agents. By conventional biochemical method, 16 isolates were typed as biovar 1 and 23 strains were biovar 3. Strains of both biovars were recovered from clinical specimens and 0.9% saline. Vitek AMS was able to identify P. pickettii correctly, but the result of biotyping was not satisfactory. Analysis of cellular fatty acids could rapidly identify P. pickettii to the species level, but could not distinguish the different biovars. By determination of the MICs, the antibiogram could be classified into 9 patterns. Of 16 isolates of P. pickettii biovar 1, 7 (44%) belonged to pattern I, and 9 (56%) pattern II. Strains of both patterns were found in cultures of clinical specimens and 0.9% saline. Of 23 isolates of P. pickettii biovar 3, 11 (48%) belonged to pattern III, 4 (17%) pattern IV and 8 (35%) pattern V to IX. Pattern III and pattern IV were seen in isolates from clinical specimens and 0.9% saline, while pattern V to IX were only seen in isolates from clinical specimens.(ABSTRACT TRUNCATED AT 250 WORDS)