Genetic ablation of the preptin-coding portion of Igf2 impairs pancreatic function in female mice.

Preptin is a 34-amino acid peptide derived from the E-peptide of pro-insulin-like growth factor 2 and is co-secreted with insulin from ß-cells. Little is understood about the effects of endogenous preptin on whole body glucose metabolism. We developed a novel mouse model in which the preptin portion of Igf2 was genetically ablated in all tissues, hereafter referred to as preptin knockout (KO), and tested the hypothesis that the removal of preptin will lead to a decreased insulin response to a metabolic challenge. Preptin KO and wild-type (WT) mice underwent weekly fasting blood glucose measurements, intraperitoneal insulin tolerance tests (ITT) at 9, 29, and 44 wk of age, and an oral glucose tolerance test (GTT) at 45 wk of age. Preptin KO mice of both sexes had similar Igf2 exon 2-3 mRNA expression in the liver and kidney compared with WT mice, but Igf2 exon 3-4 (preptin) expression was not detectable. Western blot analysis of neonatal serum indicated that processing of pro-IGF2 translated from the KO allele may be altered. Preptin KO mice had similar body weight, body composition, ß-cell area, and fasted glucose concentrations compared with WT mice in both sexes up to 47 wk of age. Female KO mice had a diminished ability to mount an insulin response following glucose stimulation in vivo. This effect was absent in male KO mice. Although preptin is not essential for glucose homeostasis, when combined with previous in vitro and ex vivo findings, these data show that preptin positively impacts ß-cell function.NEW & NOTEWORTHY This is the first study to describe a model in which the preptin-coding portion of the Igf2 gene has been genetically ablated in mice. The mice do not show reduced size at birth associated with Igf2 knockout suggesting that IGF2 functionality is maintained, yet we demonstrate a change in the processing of mature Igf2. Female knockout mice have diminished glucose-stimulated insulin secretion, whereas the insulin response in males is not different to wild type.

Loss of labelling efficiency caused by carotid stent in pseudocontinuous arterial spin labelling perfusion study.

AIM: To elucidate the cause of cerebral hypoperfusion on the stent placement side after carotid artery stent placement (CAS) measured by pseudocontinuous arterial spin labelling (PCASL) perfusion imaging. MATERIALS AND METHODS: Consecutive patients with symptomatic internal carotid artery stenosis receiving CAS were included in the study. Cerebral blood flow (CBF) was measured by PCASL perfusion imaging at 3 T magnetic resonance imaging (MRI) the day before and 3 days after the procedure. Changes in cerebral haemodynamics after CAS were assessed. RESULTS: Twenty-two patients were included; 17 patients had increased or stationary CBF after CAS and five patients had significantly reduced CBF on the stenting side after CAS whereas CBF increased on the contralateral side. High stent position was noticed in the five patients. After labelling plane adjustment to avoid labelling on the stent, no more cerebral hypoperfusion was noticed. CONCLUSION: When using PCASL perfusion imaging to monitor post-stenting CBF, the stent may cause an artefact that leads to a low CBF in the territory of the stented vessel. Routinely adding a fast T2 star gradient-echo echo-planar-imaging covering the upper neck region before PCASL perfusion imaging to identify the stent position and avoid the stent-related artefact is recommended.

Jahn-Teller effect in VCl4.

A theoretical study is made of the Jahn-Teller and other properties of vanadium tetrachloride. Relativistic effective core potentials and corresponding valence spin-orbit operators are used with Gaussian atomic orbitals to compute self-consistent-field and spin-orbit configuration-interaction wave functions. Energy-surface parameters, electronic excitation energies, vibronic energy levels, and g factors are computed. Electron correlation is shown to have a substantial effect on the Jahn-Teller properties. As have others, we find the Jahn-Teller effect in VCl4 to be of the dynamic form.

Clinical and microbiological characteristics of urine culture-confirmed genitourinary tuberculosis at medical centers in Taiwan from 1995 to 2007.

All patients with urine culture-confirmed genitourinary tuberculosis (GUTB) diagnosed between 1995 and 2007 at two medical centers in northern Taiwan were included in this retrospective study. Genotypes of 48 preserved Mycobacterium tuberculosis (MTB) isolates from these patients were determined by spoligotyping and double repetitive element PCR (DRE-PCR) analysis. Among the 64 patients, 38 (59.4%) were male with a mean ±SD age of 60.3 ± 16.1 years old. The overall mortality rate was 26.2%. Poor prognostic factors included age over 65 years (HR = 4.03; 95%; CI: 1.27-12.76), cardiovascular disease (HR = 5.96; 95% CI: 1.98-17.92), receiving steroids (HR = 10.16; 95% CI: 2.27-45.47), not being treated (HR 4.81; 95% CI 1.12-20.67). Spoligotyping and DRE-PCR of the 48 MTB isolates revealed that 20 (41.7%) belonged to the Beijing family and 40 (83.3%) had a clustering pattern. Identification of a Beijing family isolate was not correlated with drug resistance or mortality. Clustering strains were likely to be resistant to isoniazid (OR = 4.71; 95% CI: 1.10 to 23.53). In this study of patients with urine culture-confirmed GUTB, age and coexisting diseases were independently associated with an unfavorable outcome. The Beijing family was the dominant genotype of GUTB isolates, but did not correlate with drug resistance or outcome.

Clinical and genotypic characteristics of extensively drug-resistant and multidrug-resistant tuberculosis.

The aims of this study were to compare the clinical features of patients with extensively drug-resistant tuberculosis (XDRTB) and multidrug-resistant tuberculosis (MDRTB) and the genotypic characteristics of these Mycobacterium tuberculosis isolates. A total of 90 non-HIV-infected patients having MDRTB (n = 80, not including XDRTB, 88.9%) and XDRTB (n = 10, 11.1%) were identified from 2000 to 2007. Genotypes of the 39 available isolates were evaluated by spoligotyping and the 24-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) scheme. Patients with XDRTB were more likely to have previous history of TB and cavitary lung lesions than patients with MDRTB (P < 0.05). Among the 39 isolates for spoligotyping analysis, the Beijing genotype was the most common (n = 21, 53.8%). Four (44.4%) isolates of XDRTB and 17 (56.7%) isolates of MDRTB belonged to Beijing family genotypes. There was no significant difference in the anti-tuberculosis drug resistance rates between Beijing and non-Beijing genotype isolates or in the clinical features of infected patients. In conclusion, significant differences in clinical manifestations existed among patients with XDRTB and MDRTB. The clinical features of patients infected with the Beijing genotype and the drug resistance profile of the Beijing genotype isolates were similar to those for the non-Beijing family genotype.

Hospital-acquired pneumonia and bacteremia caused by Legionella pneumophila in an immunocompromised patient.

The Legionella species is an important cause of communityand hospital-acquired pneumonia. Bacteremic pneumonia caused by L. pneumophila is rarely reported. We describe the first reported case of hospital-acquired pneumonia and bacteremia caused by L. pneumophila from Taiwan in a patient with idiopathic thrombocytopenic purpura who received steroid treatment. The patient was successfully treated with ceftazidime and clindamycin initially, followed by ciprofloxacin for 14 days. The blood isolate was further confirmed by 16S rDNA sequence analysis.

Rapid identification of the Mycobacterium tuberculosis complex by an enzyme-linked immunosorbent assay.

SETTING: A medical centre in Taipei, Taiwan. OBJECTIVE: To investigate the performance of an enzyme-linked immunosorbent assay (ELISA) using anti-early secreted antigenic target 6 and culture filtrate protein 10 antibodies (MeDiPro Mycobacterium tuberculosis Antigen ELISA) for the detection of M. tuberculosis in positive signals of Mycobacterium Growth Indicator Tubes (MGIT; BACTEC MGIT 960 system). DESIGN: A total of 208 consecutive clinical samples, including 185 respiratory specimens and 23 non-respiratory specimens, with positive signals in MGIT were analysed. The assay was performed on Days 1 and 7. The ELISA and conventional culture results were compared. RESULTS: Among the tubes with positive signals, 86 (41.3%) were M. tuberculosis, 55 (26.4%) were non-tuberculous mycobacteria and 67 (32.2%) were negative for mycobacteria. The sensitivity of the ELISA for tubes with positive signals (initial smear with positive acid-fast bacilli) on Days 1 and 7 was respectively 75.6% (70.5%) and 96.5% (97.7%), and the specificity was respectively 98.4% (100%) and 100% (100%). CONCLUSION: Our results show that the MeDiPro M.tuberculosis Antigen ELISA is a simple, rapid assay (<3 h) for M. tuberculosis antigen detection, especially on Day 7 of incubation with positive signals in the BACTEC MGIT 960 system.

Enhancer-binding activity of the tal-1 oncoprotein in association with the E47/E12 helix-loop-helix proteins.

Almost 30% of patients with T-cell acute lymphoblastic leukemia (T-ALL) bear structural alterations of tal-1, a presumptive proto-oncogene that encodes sequences homologous to the helix-loop-helix (HLH) DNA-binding and dimerization domain. Analysis of the tal-1 gene product reveals that its HLH domain mediates protein-protein interactions with either of the ubiquitously expressed HLH proteins E47 and E12. The resultant tal-1/E47 and tal-1/E12 heterodimers specifically recognize the E-box DNA sequence motif found in eucaryotic transcriptional enhancers. Hence, the tal-1 protein shares biochemical properties with other tissue-specific HLH proteins that control cell type determination during myogenesis (e.g., MyoD1) and neurogenesis (e.g., achaete-scute). The data suggest that HLH heterodimers involving tal-1 may function in vivo as transcriptional regulatory factors that influence cell type determination during hematopoietic development.

Preferred sequences for DNA recognition by the TAL1 helix-loop-helix proteins.

Tumor-specific activation of the TAL1 gene is the most common genetic alteration seen in patients with T-cell acute lymphoblastic leukemia. The TAL1 gene products contain the basic helix-loop-helix (bHLH) domain, a protein dimerization and DNA-binding motif common to several known transcription factors. A binding-site selection procedure has now been used to evaluate the DNA recognition properties of TAL1. These studies demonstrate that TAL1 polypeptides do not have intrinsic DNA-binding activity, presumably because of their inability to form bHLH homodimers. However, TAL1 readily interacts with any of the known class A bHLH proteins (E12, E47, E2-2, and HEB) to form heterodimers that bind DNA in a sequence-specific manner. The TAL1 heterodimers preferentially recognize a subset of E-box elements (CANNTG) that can be represented by the consensus sequence AACAGATGGT. This consensus is composed of half-sites for recognition by the participating class A bHLH polypeptide (AACAG) and the TAL1 polypeptide (ATGGT). TAL1 heterodimers with DNA-binding activity are readily detected in nuclear extracts of Jurkat, a leukemic cell line derived from a patient with T-cell acute lymphoblastic leukemia. Hence, TAL1 is likely to bind and regulate the transcription of a unique subset of subordinate target genes, some of which may mediate the malignant function of TAL1 during T-cell leukemogenesis.

Oncogenic MCT-1 activation promotes YY1-EGFR-MnSOD signaling and tumor progression.

Tumor cells often produce high levels of reactive oxygen species (ROS) and display an increased ROS scavenging system. However, the molecular mechanism that balances antioxidative and oxidative stress in cancer cells is unclear. Here, we determined that oncogenic multiple copies in T-cell malignancy 1 (MCT-1) activity promotes the generation of intracellular ROS and mitochondrial superoxide. Overexpression of MCT-1 suppresses p53 accumulation but elevates the manganese-dependent superoxide dismutase (MnSOD) level via the YY1-EGFR signaling cascade, which protects cells against oxidative damage. Conversely, restricting ROS generation and/or targeting YY1 in lung cancer cells effectively inhibits the EGFR-MnSOD signaling pathway and cell invasiveness induced by MCT-1. Significantly, MCT-1 overexpression in lung cancer cells promotes tumor progression, necrosis and angiogenesis, and increases the number of tumor-promoting M2 macrophages and cancer-associated fibroblasts in the microenvironment. Clinical evidence further confirms that high expression of MCT-1 is associated with an increase in YY1, EGFR and MnSOD expression, accompanied by tumor recurrence, poor overall survival and EGFR mutation status in patients with lung cancers. Together, these data indicate that the MCT-1 oncogenic pathway is implicated in oxidative metabolism and lung carcinogenesis.

The MAP kinase phosphorylation site of TAL1 occurs within a transcriptional activation domain.

Alteration of the TAL1 gene is the most common genetic lesion found in patients with T cell acute lymphoblastic leukemia. TAL1 encodes a basic helix-loop-helix transcription factor that is phosphorylated on serine residue 122 by the mitogen-activated protein (MAP) kinase ERK1. Here we show that the amino-terminal sequences of TAL1 (residues 1-166) function in vivo as a transcriptional activation domain. Mutation of serine residue 122 reduces the potency of the transactivation domain by more than half. The data suggest that the amino-terminal transactivation domain of TAL1 is positively regulated by S122 phosphorylation and that the functional properties of TAL1 can be influenced by signal transduction pathways that involve the MAP kinases.

Products of the TAL1 oncogene: basic helix-loop-helix proteins phosphorylated at serine residues.

TAL1 gene rearrangement is observed in nearly 30% of patients with T-cell acute lymphoblastic leukemia (T-ALL), and thus it represents the most common genetic lesion associated with this disease. Nevertheless, the presence of TAL1 gene products in normal or leukemic cells has not been reported. Therefore, immunoprecipitation with anti-TAL1 antisera was used to demonstrate the presence of TAL1 phosphoproteins, pp42TAL1 and pp22TAL1, in both T-ALL and erythroleukemia cell lines. The pp42TAL1 and pp22TAL1 proteins appear to be phosphorylated forms of full-length and truncated TAL1 gene products respectively. Phosphoamino acid analysis revealed that pp42TAL1 contains phosphoserine residues. The TAL1 phosphoproteins were detected in all of the T-ALL cell lines that harbor obvious TAL1 gene rearrangements. Interestingly, pp42TAL1 and pp22TAL1 were also present in some, but not all, of the T-ALL lines without detectable TAL1 gene alterations. Therefore, TAL1 activation may promote leukemogenesis in a far greater proportion of T-ALL patients than the 30% that bear gross TAL1 gene rearrangements.

Long-term results of coronary artery bypass grafting in patients with dialysis-dependent renal failure.

AIM: Coronary artery disease is the main cause of mortality and morbidity in dialysis-dependent renal failure patients. Both the prevalence and incidence of renal failure are high in Taiwan. However, there were few reports exploring the outcome of coronary aortic bypass grafting (CABG) in these patients. The aim of this study was to determine the survival outcome and risk factors for mortality from CABG in this population. METHODS: The operative, early postoperative and late results of 170 dialysis patients undergoing isolated coronary artery bypass grafting from January, 2000 to January, 2012 were retrospectively reviewed. Operative mortality, long-term survival, and risk factors were analyzed. RESULTS: One hundred and seventeen patients (68.8%) were male, and the mean age was 61.5±10.3 years (range, 34-86 years). Follow-up was 40.3±32.1 months. Operative mortality was 8.2%. Actuarial survival, including operative mortality, was 81±3% at 1 year, 68±4% at 3 years, 58±5% at 5 years and 49±6% at 10 years, better than the natural course of dialysis-dependent renal failure patients. Age, emergent operation, postoperative ventricular tachycardia or fibrillation, postoperative intra-aortic balloon pump insertion, gastrointestinal bleeding, and left internal mammary artery graft were significant predictors of operative or long term mortality. Most causes of late death were due to infection or cardiac events. CONCLUSION: CABG in dialysis patients is associated with a higher incidence of complications, but has acceptable mortality. CABG is beneficial in this population. Internal mammary artery grafting may provide more favorable long term outcomes.

Cross-linking characteristics of biological tissues fixed with monofunctional or multifunctional epoxy compounds.

The cross-linking characteristics of biological tissues fixed by various epoxy compounds with different chemical structures (i.e. number of epoxide functional groups and backbone length) were investigated. Generally speaking, the tissues fixed with monofunctional fixatives were more pliable than those fixed with multifunctional fixatives. The fixation indices of the fixed tissues did not seem to be affected by the chemical structures of the fixatives. However, the number of functional groups and backbone length of the fixatives did play an important role in influencing the denaturation temperatures of the fixed tissues. In general, the denaturation temperatures of the multifunctional fixed tissues were higher than those of the monofunctional fixed tissues. Among the monofunctional fixed tissues, it was found that increasing the backbone length of the fixative decreased the denaturation temperature of the fixed tissue. This effect was present until the backbone length of the fixative became large enough.

Evaluation of an epoxy-fixed biological patch with ionically bound heparin as a pericardial substitute.

In an attempt to develop an improved pericardial substitute, we undertook the development of an epoxy-fixed biological patch with ionically bound heparin. The study was to evaluate the cross-linking characteristics of this newly developed biological patch using its glutaraldehyde-fixed counterpart as a control. In addition, the feasibility of using this newly developed biological patch as a pericardial substitute was assessed in a canine model. In the study, it was observed that the epoxy-fixed biological patch appeared more similar to the native pericardium in colour and was more pliable than its glutaraldehyde-fixed counterpart. Also, both the epoxy- and glutaraldehyde-fixed biological patches had significant increases in fixation index and denaturation temperature as compared to the fresh one (p < 0.05). In the canine study, the epoxy-fixed biological patch with ionically bound heparin was found to have significantly less adhesion formation than those currently used clinically (p < 0.05).

Antisense oligodeoxynucleotides of IGF-II selectively inhibit growth of human hepatoma cells overproducing IGF-II.

Insulin-like growth factor II (IGF-II) is expressed in many developing embryonic tissues and is involved in mammalian growth and development. After birth, serum IGF-II is mainly produced by liver cells. Many reports have indicated that IGF-II is overexpressed in some hepatocellular carcinoma (HCC) tissue. These findings imply the possible importance of this growth factor in carcinogenesis. We screened four human HCC cell lines and three rat HCC cell lines and found that HuH-7 and HepG2 cells produced fivefold more intracellular IGF-II than the other cell lines. Experimental data indicate that IGF-II functions through the intracrine mode for HuH-7 cells. To study whether the overexpression of IGF-II is significant for the growth of HCC or only a consequence of HCC development, we used antisense oligodeoxynucleotides (ATON) to arrest the translation of IGF-II mRNA, and then measured the effects on cell growth. We found that the production of IGF-II was suppressed by ATON, and the decrease of IGF-II resulted in growth inhibition of HuH-7 and HepG2. ATON had no effect on the other tested cell lines, which produced lower levels of IGF-II. The growth inhibition was mainly attributed to a decrease of cell proliferative activity. The results indicate that the IGF-II-overproducing cell lines do depend on IGF-II for growth, and ATON of IGF-II can selectively inhibit the growth of these cells. ATON may be a potential therapeutic agent for this type of HCC in vivo.

Empirical monotherapy with meropenem in serious bacterial infections in children.

The efficacy and safety profile of meropenem were analyzed according to data collected from hospitalized pediatric patients aged 4 days to 20 years who had serious bacterial infections and were treated in a major teaching hospital in Taipei. Of the 53 patients enrolled, 47 were analyzed for clinical efficacy and 53 for safety. The satisfactory clinical response rate was 57% in lower respiratory tract infection, 58% in septicemia, 100% in complicated urinary tract infection, osteomyelitis, and central nervous system infection, 83% in skin and soft tissue infection, and 93% in intra-abdominal infection. Eleven (21%) patients experienced adverse events related to meropenem. The most commonly observed adverse reactions were elevated hepatic enzymes (7.5%), increased alkaline phosphatase (3.8%), and thrombocytosis (3.8%). There was no meropenem-related seizure, withdrawal, or death. The results of this study suggested that meropenem is well tolerated even in young infants, and is effective in treating serious childhood bacterial infection. However, this study also identified a proportion of hospitalized pediatric patients with isolates that were resistant to meropenem. The trends in meropenem resistance among nosocomially acquired bacteria should be monitored closely.

Rotavirus gastroenteritis in children: 5-year experience in a medical center.

Rotavirus infection is the leading cause of childhood gastroenteritis. We retrospectively reviewed cases of rotavirus gastroenteritis at National Taiwan University Hospital from January 1993 to December 1997. During the study period there were 429 patients with rotavirus infection with ages ranging from 1 day to 16 years with a median of 13 months. The male-to-female ratio was 1.2:1. Infection occurred before the age of 2 years old in 76% of patients. The seasonal peak occurred in the late winter and early spring during 1993 to 1996, but the case number increased in late spring and summer in 1997. The G serotype of the rotavirus was identified in 302 patients (70%). Vomiting and dehydration developed more frequently following infection with G1 rotaviruses, while an increased frequency of seizures was noted following G2 infection; the differences were not statistically significant. One patient had two episodes of infection; the first one was caused by G1 rotavirus, and the strain causing the second infection could not be typed. In conclusion, the results suggest that there is a strong seasonal variation in the incidence and characteristics of rotavirus infection in Taipei area. The infections caused by G1 and G2 rotaviruses were clinically indistinguishable.

Enteric adenovirus infection in children in Taipei.

Enteric adenoviruses (EAds), including type 40 (Ad40) and 41 (Ad41), can cause acute and severe diarrhea in young children. To delineate the epidemiological features of pediatric EAds infection in Taiwan, we conducted a retrospective study of all cases of EAds gastroenteritis in children treated at National Taiwan University Hospital for the period from July 1993 to December 1997. Stool samples were tested for the presence of Ad40 or Ad41 by enzyme immunoassay (EIA). A total of 64 cases of EAds infection in 63 children aged from 8 days to 81 months old with a median age of 9.5 months treated during the study period were identified. The male-to-female ratio was 1.63 (39/24). No obvious seasonal clustering of EAds cases was noted. Most patients (76.6%) were infected before the age of 2 years. Clinical features included diarrhea (96.9%), fever (54.7%), vomiting (45.3%), mild dehydration (43.8%), symptoms of upper respiratory tract infection (21.9%), and abdominal pain (12.5%). Analysis of fecal samples in patients with diarrhea showed watery diarrhea in 72.2%, diarrhea with mucus in 20%, diarrhea with blood in 3.1% and diarrhea with mucus and blood in 1.6 % of all patients. Nearly one-half (43.5%) of the patients had diarrhea for more than 7 days. Thirty-seven patients (57.8%) were hospitalized due to gastroenteritis or other unrelated diseases, and 11 patients (17.2%) acquired enteric adenovirus infection during hospitalization for other underlying disease. Twelve patients (18.8%) had mixed infections, which included rotavirus, respiratory syncytial virus (RSV) and Salmonella species. There were no deaths in this series. The findings of this study suggest that EAds are important etiologic microbes of pediatric gastroenteritis.

Partial DiGeorge anomaly associated with 10p deletion.

We report a girl with partial DiGeorge anomaly associated with a distal chromosome 10p deletion. The initial manifestation was hypocalcemia convulsion at the age of 14 days. The patient was small for her gestational age and showed symptoms of poor feeding and inspiratory stridor. Facial dysmorphisms included a cupped ear, hypertelorism downslanted and short palpebral fissures frontal bossing, anteverted nostrils, a flat nasal bridge, and micrognathia. Developmental delay was also noted. Hypoplasia of the thymus was detected by ultrasound examination, but results of immunologic studies were all normal at 6 weeks of age. The echocardiogram, brain ultrasound, electroencephalogram, and magnetic resonance images of the brain were normal, but brainstem auditory evoked potentials showed bilateral sensorineural hearing loss. Chromosomal analysis showed 16, XX, del(10)(p12.3); the parents had normal karyotypes. After treatment with vitamin D, calcium gluconate, and magnesium sulfate, the patient's serum calcium and magnesium levels were within normal limits. She was discharged and received regular follow-up at our clinic for physical therapy and to ensure adequate supply of divalent cations. Complex partial seizure was noted at the age of 1 year and was controlled with carbamazepine. To our knowledge, this is the first Taiwanese reported to have partial DiGeorge anomaly associated with 10p deletion. We recommend that standard karyotyping should be performed in children suspected to have this anomaly.