Clinical impact of intravascular ultrasound guidance in patients of ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention with drug eluting stent

Background

There is little data about clinical role of intravascular ultrasound (IVUS)-guided Percutaneous (PCI) in the setting of ST-segment elevation myocardial infarction (STEMI).

Methods

From 2005 to 2018, a total of 8,129 patients who underwent PCI with STEMI were investigated from the Korea Acute Myocardial Infarction Registry-National Institute of Health database. Patients with Non-ST segment elevation myocardial infarction, cardiogenic shock, bare metal stent implantation, thrombolytic treatment, and coronary artery bypass graft surgery were excluded. We categorized patients into two groups based on the treatment strategy: IVUS-guided PCI group (n=1,544), and coronary angiography guidance (CAG)-guided PCI group (n=6,585). The primary endpoint was composite of major adverse cardiovascular (MACE), including, cardiac death, myocardial infarction (MI), repeat target vessel revascularization (TVR) and stent thrombosis (ST).

Results

IVUS-guided PCI was performed in 19% patients (1544/8129). After propensity score matching, there were no statistically difference in the rate of cardiac death (0% in IVUS vs. 0.26% in CAG, p=0.947), MI (2.01% vs. 2.01%, p=0.408), TVR (1.23% vs. 0.91%, p=0.131), ST (0.32% vs. 0.45%, p=0.828) and composite of MACE at 1 year between two groups (2.01% vs. 2.40%, p=0.843). Independent risk factors for MACE were diabetes mellitus and multi-vessel disease, but not IVUS-guided PCI (HR 1.167, 95% CI, 0.896–1.520, p=0.251).

Conclusion

This study suggests that routine usage of IVUS in the setting of STEMI may not be necessary. Large-scaled random study will be needed for further evaluation.

Funding Acknowledgement

Type of funding sources: None.

Upregulation of CYP17A1 by Sp1-mediated DNA demethylation confers temozolomide resistance through DHEA-mediated protection in glioma

Steroidogenesis-mediated production of neurosteroids is important for brain homeostasis. Cytochrome P450 17A1 (CYP17A1), which converts pregnenolone to dehydroepiandrosterone (DHEA) in endocrine organs and the brain, is required for prostate cancer progression and acquired chemotherapeutic resistance. However, whether CYP17A1-mediated DHEA synthesis is involved in brain tumor malignancy, especially in glioma, the most prevalent brain tumor, is unknown. To investigate the role of CYP17A1 in glioma, we determined that CYP17A1 expression is significantly increased in gliomas, which secrete more DHEA than normal astrocytes. We found that as gliomas became more malignant, both CYP17A1 and DHEA were significantly upregulated in temozolomide (TMZ)-resistant cells and highly invasive cells. In particular, the increase of CYP17A1 was caused by Sp1-mediated DNA demethylation, whereby Sp1 competed with DNMT3a for binding to the CYP17A1 promoter in TMZ-resistant glioma cells. CYP17A1 was required for the development of glioma cell invasiveness and resistance to TMZ-induced cytotoxicity. In addition, DHEA markedly attenuated TMZ-induced DNA damage and apoptosis. Together, our results suggest that components of the Sp1-CYP17A1-DHEA axis, which promotes the development of TMZ resistance, may serve as potential biomarkers and therapeutic targets in recurrent glioma.

Genetic polymorphisms in the prostaglandin pathway genes and risk of head and neck cancer

OBJECTIVE

Previous studies examining the association between genetic variations in prostaglandin pathway and risk of head and neck cancer (HNC) have only included polymorphisms in the PTGS2 (COX2) gene. This study investigated the association between genetic polymorphisms of six prostaglandin pathway genes (PGDS, PTGDS, PTGES, PTGIS, PTGS1 and PTGS2), and risk of HNC.

METHODS

Interviews regarding the consumption of alcohol, betel quid, and cigarette were conducted with 222 HNC cases and 214 controls. Genotyping was performed for 48 tag and functional single-nucleotide polymorphisms (SNPs).

RESULTS

Two tag SNPs of PTGIS showed a significant association with HNC risk [rs522962: log-additive odds ratio (OR) = 1.42, 95% confidence interval (CI): 1.01-1.99 and dominant OR = 1.58, 95% CI: 1.02-2.47; rs6125671: log-additive OR = 1.49, 95% CI: 1.08-2.05 and dominant OR = 1.96, 95% CI: 1.16-3.32]. In addition, a region in PTGIS tagged by rs927068 and rs6019902 was significantly associated with risk of HNC (global P = 0.007). Finally, several SNPs interacted with betel quid and cigarette to influence the risk of HNC.

CONCLUSIONS

Genetic variations in prostaglandin pathway genes are associated with risk of HNC and may modify the relationship between use of betel quid or cigarette and development of HNC.

BPR1J-097, a novel FLT3 kinase inhibitor, exerts potent inhibitory activity against AML

Background:

Activating mutations of Fms-like tyrosine kinase 3 (FLT3) constitute a major driver in the pathogenesis of acute myeloid leukaemia (AML). Hence, pharmacological inhibitors of FLT3 are of therapeutic interest for AML.

Methods:

The effects of inhibition of FLT3 activity by a novel potent FLT3 inhibitor, BPR1J-097, were investigated using in vitro and in vivo assays.

Results:

The 50% inhibitory concentration (IC₅₀) of BPR1J-097 required to inhibit FLT3 kinase activity ranged from 1 to 10 nM, and the 50% growth inhibition concentrations (GC₅₀s) were 21±7 and 46±14 nM for MOLM-13 and MV4-11 cells, respectively. BPR1J-097 inhibited FLT3/signal transducer and activator of transcription 5 phosphorylation and triggered apoptosis in FLT3-driven AML cells. BPR1J-097 also showed favourable pharmacokinetic property and pronounced dose-dependent tumour growth inhibition and regression in FLT3-driven AML murine xenograft models.

Conclusion:

These results indicate that BPR1J-097 is a novel small molecule FLT-3 inhibitor with promising in vivo anti-tumour activities and suggest that BPR1J-097 may be further developed in preclinical and clinical studies as therapeutics in AML treatments.

Characterization of invasive isolates of Streptococcus pneumoniae among Taiwanese children

Accurate molecular surveillance is important in monitoring the dynamics of Streptococcus pneumoniae. A prospective study was conducted to collect invasive isolates of S. pneumoniae from children for genetic analysis from January 2004 to December 2006 in Taiwan. PCRs were performed to detect the zmpC and zmpD genes, both encoding a metalloprotease virulence factor in pneumococci, among these invasive isolates. During the study period, 68 invasive isolates of S. pneumoniae were obtained for analysis. Serotype 14 was the most common type isolated from children with invasive disease and was significantly associated with pneumonia (OR 3.1; 95% CI] 1.1-8.8; p 0.035). Serotype 23F was significantly associated with bacteraemia (OR 7.5; 95% CI 1.8-31.3; p 0.006). The seven-valent conjugate vaccine covered 83.8% of invasive isolates, but non-vaccine serotypes were more frequently isolated from patients with underlying diseases than from patients without underlying diseases (p 0.007 by Fisher's exact test). Clonal complexes related to international clones Spain23F ST81, Spain6B ST95, England14 ST9, Taiwan19F ST236, Taiwan23F ST242 and Colombia23F ST338 accounted for 52.9% of invasive isolates. Dissemination of the penicillin-resistant clones ST876, ST46, ST76 and ST2889, which were first identified in Taiwan, was also found; 1.5% of these invasive isolates carried the zmpC gene, and 47.1% of these invasive isolates carried the zmpD gene. In conclusion, the spread of certain international clones and some domestic antibiotic-resistant clones resulted in invasive diseases among Taiwanese children.

Synthetic biodegradable microparticles for articular cartilage tissue engineering

Articular cartilage tissue engineering procedures require the transplantation of chondrocytes that have been expanded in vitro. The expansion is carried out for a considerable time and can lead to a modulation of cell phenotype. However, microcarrier cultures have been shown to allow cell expansion while maintaining the phenotype. Here, we have used the biodegradable polyester poly(lactide-co-glycolide) (PLGA) in the form of microspheres and irregular shaped microparticles with a diameter between 47 and 210 microm. Surface modification of particles was carried out by ammonia plasma treatment and subsequent adsorption of collagen. Alternatively, particles were modified by partial hydrolysis and subsequent immobilization of an amine-terminated dendrimer. Each surface modification step was characterized by X-ray photoelectron spectroscopy. The effectiveness of the surface modification procedures was demonstrated by in vitro cell culture experiments using sheep articular cartilage chondrocytes. A significant influence of both the particle shape and the surface chemistry on the proliferation rate was observed while the phenotype was maintained independent of the surface chemistry or particle shape. Chondrocytes cultured on PLGA microspheres were further assessed for cartilage tissue formation in collagen type I gels in nude mice. The tissue that were formed showed the appearance of a hyaline-like cartilage and the presence of the microspheres substantially reduced the degree of collagen gel contraction over 1-2 months.

Performance of AEP Monitor/2-derived composite index as an indicator for depth of sedation with midazolam and alfentanil during gastrointestinal endoscopy

BACKGROUND AND OBJECTIVE

The A-Line auditory evoked potential index (AAI) (AEP Monitor/2, Danmeter A/S, Odense, Denmark) is a newly developed composite parameter representing the degree of hypnosis. We conducted a prospective, observational study to explore the performance and validity of the AAI during conventional sedation for gastrointestinal (GI) endoscopy.

METHODS

Thirty adults of either sex, age <65, scheduled for combined oesophagogastroduodenoscopy (OGD) and colonoscopy under sedation with intravenous (i.v.) midazolam and alfentanil were enrolled. The sedative end-point was set at the Observer's Assessment of Alertness/Sedation (OAA/S) score less than 4. An AEP Monitor/2 was used in all patients. AAI, sedation scores, heart rate (HR), blood pressure (BP) and SPO2 were recorded every 2 min up to the end of the procedure. Receiver operator characteristic analysis was used to test validity and to select optimal sedation.

RESULTS

There was a significantly positive correlation between AAI and OAA/S scores (rho = 0.886; P < 0.001). The AAI also showed significant differences between subsequent levels of sedation scores (P < 0.001). AAI greater than 54 indicated fully awake or minimal sedation and values between 54 and 42 were suggestive of moderate sedation. Values between 42 and 34 were associated with moderate to deep sedation and readings below 34 were associated with deep sedation. The relative risk of SPO2 < 95% for OAA/S = 2 compared with 3 was 15.98 (95% confidence interval (CI): 3.94-64.81).

CONCLUSIONS

AAI is an effective tool for monitoring sedation during GI endoscopy induced by i.v. midazolam and alfentanil.

Evaluation of wound healing effect on skin-defect nude mice by using human dermis-derived mesenchymal stem cells

We report that human dermis-derived mesenchymal stem cells (hDMSCs) possess differentiation potential of epidermis facilitating wound healing in skin-defect nude mice in combination with the treatment using gelatin/thermosensitive poly N-isopropylacrylamide (pNIPAAm)/polypropylene (PP). The results showed that the rate of cell growth and wound recovery in the hDMSC and gelatin/pNIPAAm/PP-treated group was significantly greater than those in the gelatin/pNIPAAm/PP-treated only group (P < .01). The reepithelialization marker of human pan-cytokeratin was also significantly increased on days 14 and day 21 in the wound site of hDMSCs and gelatin/pNIPAAm/PP-treated group. Furthermore, the stem cell marker of human CD13 gradually decreased during the period of wound healing. In sum, this novel method provided a transferring system for stem cell therapy, maintaining its temperature-sensitive property of easy peeling by lower temperature treatment.

Effect of orthographic and phonological similarity on false recognition of drug names

Health professionals and patients tend to confuse drugs with similar names, thereby threatening patient safety. One out of four medication errors voluntarily reported in the US involves this type of drug name confusion. Cognitive psychology offers insight into how and why these errors occur. The objective of this investigation was to examine the effect of orthographic (i.e., spelling) and phonological (i.e., sound) similarity on the probability of making recognition memory errors (i.e., false recognitions). Prospective, computer-based, recognition memory experiments on 30 pharmacists and 66 college students were conducted. Participants viewed a study list of drug names and then a test list. The test list was twice as long as the study list and contained distractor names at progressively increasing levels of similarity to the study words. The task was to identify which test names were on study list and which were new. The main outcome measure was probability of making a false recognition error (i.e., of saying a new name was on the study list). Among pharmacists and college students, there was a strong and significant effect of similarity on the probability of making a false recognition error. It was concluded that both orthographic (i.e., spelling) and phonological (i.e., sound) similarity increase the probability that experts and novices will make false recognition errors when trying to remember drug names. Similarity is easily and cheaply measured, and therefore, steps should be taken to monitor and reduce similarity as a means of reducing the likelihood of drug name confusions.

Normalization of retinal vascular permeability in experimental diabetes with genistein

PURPOSE

To study the effects of genistein, a tyrosine kinase inhibitor, on retinal vascular permeability in an experimental diabetic rat model.

METHODS

Seventy-two rats were equally divided into four groups: (1) nondiabetic control group, (2) diabetic control group, (3) diabetic rats receiving 150 mg genistein/kg food, and (4) diabetic rats receiving 300 mg genistein/kg food. Diabetes was induced by streptozotocin injection in the three diabetic groups. Rats were fed diets with or without genistein and followed for 6 months. Retinal vascular permeability was assessed by measuring radiolabeled sucrose leakage into the retina and by Western blot analysis for total retinal albumin. Retinal phosphotyrosine levels and proliferating cell nuclear antigen (PCNA) were also evaluated by Western blot analysis.

RESULTS

Diabetic control rats had markedly increased retinal vascular leakage of radiolabeled sucrose compared with nondiabetic control rats. Diabetic rats receiving oral genistein had significantly less retinal vascular leakage of radiolabeled sucrose than diabetic control rats in a dose-response fashion. Diabetic control rats had increased levels of phosphotyrosine, retinal albumin, and PCNA by Western blot analysis compared with nondiabetic control rats. Rats receiving 300 mg of genistein had decreased retinal albumin by Western blot analysis. Western blot analysis demonstrated a dose-response decrease in retinal phosphotyrosine levels and PCNA in genistein-treated diabetic rats compared with diabetic control rats.

CONCLUSIONS

Long-term oral administration of genistein significantly inhibits retinal vascular leakage in experimentally induced diabetic rats. Tyrosine kinase inhibition may be a useful pharmacological approach for the treatment of diabetic-induced retinal vascular leakage.

Mitogen-activated protein kinase kinase inhibitor PD98059 blocks the trans-activation but not the stabilization or DNA binding ability of hypoxia-inducible factor-1alpha

Under low oxygen tension, cells increase the transcription of specific genes that are involved in angiogenesis, erythropoiesis, and glycolysis. Hypoxia-induced gene expression primarily depends on the stabilization of the alpha-subunit of hypoxia-inducible factor-1 (HIF-1alpha), which acts as a heterodimeric trans-activator. Our results indicate that stabilization of HIF-1alpha protein by treatment of proteasome inhibitors, is not sufficient for hypoxia-induced gene activation, and an additional hypoxia-dependent modification is necessary for gene expression by HIF-1alpha. Here, we demonstrate that mitogen-activated protein kinase kinase-1 (MEK-1) inhibitor PD98059 does not change either the stabilization or DNA binding ability of HIF-1alpha but it inhibits the trans-activation ability of HIF-1alpha, thereby it reduces the hypoxia-induced transcription of both an endogenous target gene and a hypoxia-responsive reporter gene. We found that hypoxia induced p42/p44 mitogen-activated protein kinases (MAPKs) that are target protein kinases of MEK-1, and that expression of dominant-negative p42 and p44 MAPK mutants reduced HIF-1-dependent transcription of the hypoxia-responsive reporter gene. Our results are the first to identify that hypoxia-induced trans-activation ability of HIF-1alpha is regulated by different mechanisms than its stabilization and DNA binding, and that these processes can be experimentally dissociated. MEK-1/p42/p44 MAPK regulates the trans-activation, but not the stabilization or DNA binding ability, of HIF-1alpha.

The effect of tissue plasminogen activator on premacular hemorrhage

BACKGROUND AND OBJECTIVE

Early vitrectomy is recommended for eyes with premacular hemorrhage, which causes fibrovascular proliferation and macular traction. The purpose of this study was to investigate the therapeutic effects of tissue plasminogen activator (tPA) on premacular hemorrhage, and the clearing of hemorrhage from the macula.

PATIENTS AND METHODS

The authors injected tPA (25-37.5 microg) into the vitreous cavity of 13 eyes with premacular hemorrhage. The causes of premacular hemorrhage were diabetic retinopathy in 11 eyes and traumatic injuries in 2 eyes. Prior to tPA injection, 4 eyes had complete posterior vitreous detachment (PVD) and 9 eyes had no PVD.

RESULTS

After tPA injection, the hemorrhages in 10 eyes were completely absorbed. They were absorbed partially in 2 eyes and were not absorbed at all in 1 eye. Absorption of hemorrhage in the 4 eyes with complete PVD took an average of 5.5 days, and in the 6 eyes with no PVD, it took an average of 12.7 days (P=0.002). After tPA injection, visual acuity improved in 9 eyes, remained stable in 3 eyes, and worsened in 1 eye. In 5 eyes, pars plana vitrectomy (PPV) was required after tPA injection because of recurrent vitreous hemorrhage, macular traction or nonabsorbed premacular hemorrhage.

CONCLUSION

TPA seems to be a good alternative method of treatment for premacular hemorrhage, especially in eyes with complete PVD. It appears to improve vision and defer the need for PPV.

Age-related retinal pigment epithelium and Bruch's membrane degeneration in senescence-accelerated mouse

PURPOSE

To investigate age-related changes in the retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris in the senescence-accelerated mouse (SAM).

METHODS

The external and eyecup features and light and electron microscopic findings were examined in three male and two female mice of a senescence-prone mouse strain (SAM P(8)) monthly for 12 months. These results were compared with those in age-matched mice of similar background but senescence resistant (SAM R(1)). Choroidal vascular casts were prepared at 12 months in seven mice each of the SAM P(8) and SAM R(1) strains. Quantitative analysis of area of choriocapillaris was performed by automated image analysis, and the results were analyzed by paired Student's t-test.

RESULTS

We found in the SAM P(8) strain that hair loss, coarseness of hair texture, and ulceration of skin appeared and increased as the age advanced (at approximately 5-9 months). Eyecup examination showed no differences. Light and electron microscopy revealed progressively more prominent abnormalities in the RPE and Bruch's membrane mice older than 10 months. Two of the five SAM P(8) mice older than 11 months showed what appeared to be intra-Bruch's membrane choroidal neovascularization. The RPE and Bruch's membrane appeared normal in the SAM R(1) strain. In the SAM P(8), vascular casts of the choriocapillaris showed a mild but significant decrease in vascular area when compared with the SAM R(1) strain at 12 months (P = 0.011).

CONCLUSIONS

Senescence accelerated mice develop progressive age-related changes in the RPE-Bruch's-choriocapillaris complex that have features that may be relevant in the study of age-related macular changes in humans.

CM1, a possible novel activation molecule on human lymphocytes

CM1 (centrocyte/-blast marker 1) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on some tonsillar germinal center (GC) B cells. In single flow cytometric analysis, the bone marrow did not express these molecules nor did the PBMC or the thymocytes. The peripheral B lymphocytes showed more than 90% positive, while the peripheral T lymphocytes showed approximately 60% positive at 48 h after activation by PMA/ionomycin, respectively. A western blot analysis and an immunoprecipitation for CM1 showed a band at 70 kDa. Cross-linking of CM1 with anti-CM1 mAb induced apoptosis of the GC B cells (CD38(+)IgD(-)). Immunohistochemical staining revealed that the CM1 molecule is distributed over the entire area except the proximal dark zone of the tonsillar germinal centers. These results suggest that the CM1 molecule might be involved in differentiation of the germinal center B cells as one of the novel centrocyte markers.

Synthesis and structure-activity relationships of quaternary ammonium cephalosporins with 3-pyrazolylpyridinium derivatives

Cephalosporins with 3-pyazolylpyridinium at C-3 position, which is supposed to exhibit synergic activity of ceftazidime and cefoselis, were synthesized and their antibacterial activity against gram-positive and gram-negative was inspected.

Role of follicular dendritic cells in the apoptosis of germinal center B cells

Follicular dendritic cells (FDCs) provide the most obvious source of antigens, which are essential for the differentiation of GC B cells. It has been reported that most proliferating B cells in germinal centers undergo apoptosis. Quantitative histology shows macrophages with apoptotic debris throughout the germinal center, the highest frequency of these cells being found in the dense FDC network. Based on these findings, we hypothesized that FDC may be involved in an apoptotic pathway of the germinal center B cells. To prove this hypothesis, we performed double immunohistochemical analysis using anti-FDC mAb and peanut agglutinin (PNA), with their respective TUNEL kits. Collated data showed that a great proportion of the apoptotic cells, most of which were positive for PNA, were in close contact with FDC, which indicated an interaction between FDC and B cells in the apoptotic pathway. Further studies using double immunohistochemical staining and FACS analyses demonstrated the expression of Fas-ligand (FasL) in a subset of the FDC. These results suggest that FDC may play a role in the apoptosis of germinal center B cells via Fas-FasL interaction.

Contrast-enhanced dynamic computed tomography does not aggravate the clinical severity of patients with severe acute pancreatitis: reevaluation of the effect of intravenous contrast medium on the severity of acute pancreatitis

BACKGROUND

Contrast-enhanced abdominal computed tomography (CT) is useful in demonstrating pancreatitis necrosis, but the administration of contrast medium in animal models with acute pancreatitis may worsen the severity.

HYPOTHESIS

The use of contrast-enhanced CT in clinical patients with acute pancreatitis may actually aggravate the severity of the disease.

DESIGN

A randomized prospective study.

SETTING

Chang Gung Memorial Hospital, Taipei, Taiwan.

PATIENTS

Twenty patients with severe acute pancreatitis were randomly divided into 2 groups. Those in group A (n = 10) underwent a CT examination with a contrast-enhanced medium, and those in group B (n = 10) underwent a CT examination without a contrast-enhanced medium.

MAIN OUTCOME MEASURES

The patients' serum amylase, lipase, C-reactive protein, leukocyte, glutamicoxaloacetic transaminase, creatinine, calcium, and phosphate levels were serially checked before the CT examination and at 2, 4, 6, 8, 12, and 24 hours after the examination was performed. The biochemical data between the 2 groups were compared. The morbidity, length of stay, and mortality were also compared.

RESULTS

There were no significant changes in the level of pancreatic enzymes, C-reactive proteins, and leukocytes and in the biochemical data of either group before or after the CT examination. The difference in the previously examined values between the 2 groups was also not significant. There was also no difference in the morbidity, length of hospital stay, and mortality between the 2 groups.

CONCLUSION

Contrast-enhanced abdominal CT does not aggravate the severity of clinical patients with severe acute pancreatitis.

Similarity as a risk factor in drug-name confusion errors: the look-alike (orthographic) and sound-alike (phonetic) model

BACKGROUND

One of every four medication errors reported in the United States is a name-confusion error. The rate of name-confusion errors might be reduced if new and confusing names were not allowed on the market and if safeguards could be put in place to avoid confusion between existing names.

OBJECTIVES

To evaluate several prognostic tests of drug-name confusion, alone and in combination, with respect to their sensitivity, specificity, and overall accuracy.

RESEARCH DESIGN

Case-control study. Twenty-two different computerized measures of orthographic similarity, orthographic distance, and phonetic similarity were used to compute similarity/distance scores for n = 1,127 cases (ie, pairs of names that appeared in published error reports or national error databases) and n = 1,127 controls.

MAIN OUTCOME MEASURES

Mean similarity/distance scores were compared across cases and controls. The performance of each measure at distinguishing between cases and controls was evaluated by tenfold crossvalidation. Dose-response relationships were examined. Univariate and multivariate logistic regression models were formed and evaluated by 10 fold crossvalidation.

RESULTS

Cases had significantly higher similarity scores than controls. Every measure of similarity proved to be a significant risk factor for error. There was a significant increasing trend in the odds-ratio as a function of similarity. A three-predictor logistic regression model had crossvalidated sensitivity of 93.7%, specificity of 95.9% and accuracy of 94.8%.

CONCLUSIONS

A sensitive and specific test of drug-name confusion potential can be formed using objective measures of orthographic similarity, orthographic distance, and phonetic distance.

Correlation of deformability at a tRNA recognition site and aminoacylation specificity

The fidelity of protein synthesis depends on specific tRNA aminoacylation by aminoacyl-tRNA synthetase enzymes, which in turn depends on the recognition of the identity of particular nucleotides and structural features in the substrate tRNA. These features generally reside within the acceptor helix, the anticodon stem-loop, and in some systems the variable pocket of the tRNA. In the alanine system, fidelity is ensured by a G.U wobble base pair located at the third position within the acceptor helix of alanine tRNA. We have investigated the activity of mutant alanine tRNAs to explore the mechanism of enzyme recognition. Here we show that the mismatched pair C-C is an excellent substitute for G.U in alanine-tRNA-knockout cells. A structural investigation by NMR spectroscopy of the C-C RNA acceptor end reveals that the two cytosines are intercalated into the helix, and that C-C exists in multiple conformations. Structural heterogeneity also is present in the wild-type G.U RNA, whereas inactive Watson-Crick helices are structurally rigid. The correlation between functional and structural data suggests that the G.U pair provides a distinctive structure and a point of deformability that allow the tRNA acceptor end to fit into the active site of the alanyl-tRNA synthetase. Fidelity is ensured because noncognate and inactive mutant tRNAs are bound in the active site in an incorrect conformation that reduces enzymatic activity.

Purification and characterization of the venom phospholipases A2 from Asian monotypic crotalinae snakes

Phospholipases A2 were purified from the venoms of Asian monotypic crotalinae snakes including Callosellasma, Hypnale, Deinagkistrodon, and Tropidolaemus by a combination of gel filtration and reversed-phase chromatographic methods. One to four isoforms of the enzyme were found in each of the venoms. The venom enzymes were subjected to N-terminal sequencing up to the 30th amino acids, and their molecular weights were analyzed by electrospray-ionization mass spectrometry. Homologous antiplatelet phospholipase with a conserved Glu 6 residue was found in each of the venoms. Basic phospholipases with Trp 6 (W6) but without detectable enzyme activities were also isolated from the venom of C. rhodostoma, H. hypnale, and T. wagleri. These W6 enzymes showed strong heparin-binding affinity and capable of inducing edema in rat paws. The fact that the venoms of Callosellasma and Hypnale contain similar types of phospholipases is in accord with recent reports that these two taxa formed a clade. Deinagkistrodon venom does not contain phospholipase variants other than the Glu-6 subtype as Trimeresurus, Agkistrodon, and Protobothrops venoms do. Interestingly, the Glu-6 enzyme from T. wagleri venom has a molecular weight of 15,319 Daltons, higher than those of most other venom phospholipases. Our results show that new types of the enzyme are more likely to be found in the venom of monotypic species; the amino acid sequence data or the subtypes of venom-phospholipases are potentially useful as markers or a character system for studying higher-order systematics of venomous snakes.

Proliferation not apoptosis as a prognostic indicator in retinoblastoma

The balance between proliferation and cell death is the major determinant of tumour growth. We analysed the proliferative and apoptotic indices (PI and AI, respectively) of 33 children with retinoblastoma. PI and AI were assessed by immunohistochemistry for Ki-67 antigen and TUNEL staining, respectively. The mean PI was 21.0+/-21.1%, and higher PI was associated with more advanced tumour stage (P<0.0001) and poor clinical outcome (P<0.05). Patients in whom amplified N-myc oncogene was found (n=6) determined by the multiplex polymerase chain reaction tended to have a higher PI (37.6+/-27.2%) than those without amplified N-myc (n=27; PI=17.3+/-18.1). A PI value of over 40% was clearly associated with an unfavourable prognosis. The AI, however, did not correlate with any of the other variables analysed. The findings suggest that proliferation, but not apoptosis, is of critical significance in retinoblastoma biology. PI, as determined by the Ki-67 antigen labelling index, seems to be a relevant histopathological parameter that can predict the clinical outcome of retinoblastoma.

Cecropin D-like antibacterial peptides from the sphingid moth, Agrius convolvuli

Two major antibacterial peptides were isolated and purified from immunized larval hemolymph of Agrius convolvuli. Acid extraction, gel filtration, ultrafiltration, and reversed-phase FPLC were used for purification of peptides. These peptides had similar molecular mass and amino acid composition. Moreover, 21 of the first 23 N terminal residues were identical. The peptides were highly homologous with cecropin D in size and primary sequence, and named Agrius cecropin D1 and D2. The molecular masses of Agrius cecropin D1 and D2 were 3,879.39 and 3,839.27, respectively. In antibacterial and hemolytic assays, Agrius cecropin D showed potent antibacterial activities against a panel of Gram positive and negative bacteria without hemolytic activity against human red blood cells. Notably, our antibacterial assay revealed Agrius cecropin D possessed stronger or at least equivalent activities against B. megaterium than cecropin A. It suggests that Agrius cecropin D, which has an alternative structure from cecropin D, could be the model for the development of peptide antibiotics. Arch.

Localization of transferrin binding protein in relation to iron, ferritin, and transferrin receptors in the chicken cerebellum

We have demonstrated that transferrin binding protein (TfBP), ferritin, and iron, are specifically localized in Bergmann glia, while the transferrin receptor is confined to Purkinje cells in the chicken cerebellum. The results of this study suggest that Bergmann glia have previously undescribed functions related to iron regulation such as sequestration of iron and the maintenance of iron homeostasis in the cerebellum.

Nucleic acids structure and recognition

A growing understanding of the diversity of structures and biological functions of DNA and RNA, coupled with progress in synthetic and spectroscopic techniques, have allowed remarkable progress in NMR studies of nucleic acids. Here we review novel principles of nucleic acid structure and recognition revealed by these studies and highlight opportunities for future progress.

Predilection for supracondylar fractures in children with cubital recurvatum

It has been a common observation that children with supracondylar fracture of the humerus tend to demonstrate hyperextensibility of their elbow joints. In this study, we measured and compared the degree of hyperextension of the uninjured elbow of children less than sixteen years old who sustained either a supracondylar or a distal radial fracture. We concluded that children with higher degree of hyperextension in the elbow are more likely to sustain a supracondylar fracture than a distal radius fracture during a fall on the outstretched hand.

The structure of an RNA "kissing" hairpin complex of the HIV TAR hairpin loop and its complement

We have used nuclear magnetic resonance (NMR) to obtain the structure of an RNA "kissing" hairpin complex formed between the HIV-2 TAR hairpin loop and a hairpin with a complementary loop sequence. Kissing hairpins are important in natural antisense reactions; their complex is a specific target for protein binding. The complex has all six nucleotides of each loop paired to form a bent quasicontinuous helix of three coaxially stacked helices: two stems plus a loop-loop interaction helix. Experimental constraints derived from heteronuclear and homonuclear NMR data on 13C and 15N-labeled RNA led to a structure for the loop-loop helix with an average root-mean-square deviation of 0.83 (+/-0.10) A for 33 converged structures relative to the average structure. The loop-loop helix of the kissing complex is distorted compared to A-form RNA. Its major groove is blocked by the phosphodiester bonds that connect the first loop residue of each hairpin with its own stem, and it is flanked by two negatively charged phosphate clusters. The loop-loop helix has alternating helical twists between adjacent base-pairs. The base-pairs at the helix junctions are overwound and three base-pairs near the helix junctions adopt high propeller twists. All these changes reduce the distance needed for the bridging phosphodiester bonds connecting each stem and loop to cross the major groove of the loop-loop helix, and result in a deformed RNA helix with localized perturbations in the minor groove surface. The alternating helical twist pattern, plus other distortions in the loop-loop helix may be important for Rom protein recognition of the kissing hairpin complex.

Effects of n-3 and n-6 fatty acids on plasma eicosanoids and liver antioxidant enzymes in rats receiving total parenteral nutrition

The effect of total parenteral nutrition (TPN) enriched with n-3 or n-6 fatty acids on the concentration of plasma eicosanoids was evaluated in rats. Rats were divided into three groups: the control group (n = 6) was fed a chow diet and infused with saline only. Two experimental groups (n = 11, 13) received TPN solutions at an energy level of 30 kcal/100g body weight with 40% energy provided as fat. The experimental groups were maintained on TPN for a period of 7 d. The basal TPN solutions were isonitrogenous and identical in nutrient composition except for differences in lipid source. One experimental group received a safflower oil emulsion, whereas the other group received a fish oil emulsion. At the end of the experimental period, plasma 6-keto prostaglandin F1 alpha, thromboxane B2, bleeding time, lipid peroxidation products, and antioxidant enzymes of liver were analyzed. The results demonstrated that the fish oil group had lower 6-keto prostaglandin F1 alpha concentration than the safflower oil group. Also, plasma thromboxane B2 was the lowest in the fish oil group among the three groups. There was no difference in bleeding time among the groups. With regard to liver lipid peroxidation products, malondialdehyde concentration was not higher in the fish oil group, whereas superoxide dismutase and glutathione peroxidase activities were lower in the fish oil group compared with the control and safflower oil groups. The results suggest that TPN prepared with fish oil fat emulsion causes less accumulation of lipid peroxidation products in the liver of rats, and may be beneficial in preventing platelet aggregation.

[Endoscopic diagnosis and clinical experience of colonic tuberculosis]

From February 1979 to May 1994, 18 cases of colonic tuberculosis were detected by colonscopy at Chang Gung Momorial Hospital, Linkou Medical Center. There were 10 males and 8 females, with mean age of 43.6. In ten, the diagnosis was confirmed histologically or bacteriologically in colonic biopsy material and post-operated lymph nodes. The remaining 8 patients was suspected on colonoscopy, and had good response to antituberculous therapy. The major symptoms were abdominal pain (83%), diarrhea (67%), and body weight loss (61%). Average duration from symptoms to diagnosis was 4.1 months. Chest X-ray revealed active pulmonary tuberculosis in 14 of 18 patients (78%), 4 of 14 patients were military type. The colonic tuberculosis involved in ileocecal area in 6, ileocecum and contiguous colonic regions in 7, segmental colonic involvement in 4, and pancolitis in 1 patient. Multiple ulceration and ulcerohypertrophic lesions were the major colonoscopic findings. Typical caseating granuloma were found in 5 cases (36%) from colonoscopic biopsy, the other 5 from surgical resected specimens. Antituberculous therapy produced remarkable symptomatic improvement in all patients except 2 cases complicated with intestinal obstruction necessitating laparotomy. Colonoscopy with biopsy is a useful diagnostic tool in early diagnosis and avoiding unnecessary laparotomy in colonic tuberculosis.

An immunohistochemical localization of transferrin binding protein in the chicken respiratory tract

Transferrin binding protein (TfBP), a glycoprotein, is originally purified from the chicken oviduct. Recently, TfBP has been revealed as a novel transferrin binding protein, structurally related to the chicken heat shock protein 108. The physiological function of this protein, however, has not yet been established. Antiserum to TfBP was found to stain selectively transferrin- and iron-rich oligodendrocytes of the normal chicken brain, suggesting a role for this protein in connection with transferrin and iron storage in these cells. In this study, we further demonstrate a TfBP-immunoreactivity in the chicken respiratory tract mucosa, where transferrin is known to be present and have antioxidant and antibacterial properties. A strong TfBP immunoreactivity was revealed in certain regions of the respiratory tract. In the trachea and bronchi, TfBP-immunoreactive product was localized specifically to the mucous gland cells, whereas ciliated epithelial cells were negative. In the lung, TfBP immunoreactivity was mostly confined to the parabronchi and atria. The immunoreactive products were found in the cytoplasm of the epithelial cells lining the parabronchial and atrial walls. These findings suggest that the presence of TfBP in the airway mucosa may be a necessary condition for transferrin concentration in the extracellular milieu of the respiratory tract.

Clinical challenge--an experience of spontaneous transmural rupture of the oesophagus in Taiwan

In Taiwan, spontaneous oesophageal rupture is uncommon but the outcome is often lethal because of failure to make an early diagnosis. We have analysed clinical data, management and the risk factors that affect mortality for a consecutive series of 11 patients who had spontaneous oesophageal perforation between 1983 and 1994. The primary symptom was chest or abdominal pain, which was present in 100% of patients; 91% of patients had abnormal chest x-ray (63% pleural effusion, 46% pneumomediastinum, 37% subcutaneous emphysema). In our series of patients the lower thoracic area was the most common location of the perforation (80% of patients. There were no statistically significant differences in mortality due to age, underlying disease, perforation size, location or surgical methods. A poor prognosis seems to be correlated with the time elapsed between the perforation and treatment (especially if > 72 hours) (p < 0.05), respiratory failure (p < 0.05), and heavy contamination of the mediastinum (p < 0.05). The clinical findings depend on the location and time of perforation. History, chest x-ray and oesophagogram are the most useful diagnostic tools. Early diagnosis and treatment are mandatory for these patients.

Prospective, randomized trial of hypertonic glucose water and sodium tetradecyl sulfate for gastric variceal bleeding in patients with advanced liver cirrhosis

BACKGROUND AND STUDY AIMS

Information about the appropriate endoscopic treatment of gastric variceal bleeding is sparse. We therefore designed a prospective and randomized study to evaluate and compare efficacy and complication rates of two agents, hypertonic glucose water (50% GW) and sodium tetradecyl sulfate (STS), in treating acute gastric variceal bleeding after esophageal varix eradication.

PATIENTS AND METHODS

Of 51 patients with advanced cirrhosis of the liver (Child's C), with acute gastric variceal bleeding initially evaluated, 25 patients were randomized to receive 1.5% STS and 26 to receive 50% glucose water. Treatment was aimed at achieving initial and permanent hemostasis by variceal eradication.

RESULTS

Control of acute gastric variceal bleeding was achieved in 80% of the STS group and 92% of the GW group. The rebleeding rate in the STS group was 70%, while in the GW group it was 30% (P < 0.05). Overall, obliteration was achieved in only 32% of the STS group and 81% of the GW group during admission (P < 0.05). There was a trend toward a higher gastric ulcer rate in the STS group compared with the GW group (92% vs. 30%; P < 0.05). The rebleeding control rate and permanent hemostasis rate in the GW group (70%, 54%) were also significantly higher than in the STS group (21%, 12%; P < 0.05; P < 0.05). The hospital mortality for the STS group was 50%, and for the GW group 30%.

CONCLUSION

Treatment with hypertonic glucose water in gastric vericeal bleeding was superior to treatment with STS in controlling bleeding and in achieving vericeal obliteration, less rebleeding, and a lower complication rate. The results of this study suggest that hypertonic glucose water is a clinically effective, easily available, and safe sclerosing agent.

Endoscopic injection sclerotherapy of bleeding duodenal varices

Bleeding from duodenal varices is a rare finding in patients with liver cirrhosis. We report a 43 year old male with alcoholic liver cirrhosis who presented with upper gastrointestinal bleeding. Panendoscopy identified, prominent tortuous varices over the second portion of duodenum with spurting of blood. At first, the varices were treated successfully with sodium tetradecyl sulfate and bleeding stopped. Consequent endoscopic sclerotherapy was done 1 week later. The varices almost disappeared 2 weeks after the second endoscopic sclerotherapy and the patient was in good condition following this.

Acute hepatitis A with coexistent hepatitis C virus infection presenting as a virus-associated hemophagocytic syndrome: a case report

A 23-yr-old male with acute hepatitis A and coexistent hepatitis C became critically ill 3 wk after the onset of fever and jaundice with progressive anemia, thrombocytopenia, and hepatosplenomegaly. Bone marrow biopsy revealed hemophagocytosis. Despite aggressive supportive treatment with parenteral steroids, the patient died of disseminated intravascular coagulopathy with gastrointestinal bleeding. Necropsy of the liver showed histiocyte aggregation in the portal area with hemophagocytosis.

Prevalence and prognostic significance of bacterascites in cirrhosis with ascites

The prevalence and prognostic significance of bacterascites (BA) were prospectively studied in 443 predominantly HBsAg-positive cirrhotic patients with ascites. Spontaneous bacterial peritonitis (SBP), culture-negative neutrocytic ascites (CNNA), and BA were identified in 12.4%, 8.4%, and 10.8%, respectively. Of these, 67%, 70%, and 71%, respectively, had peritonitis-related signs or symptoms. Among patients with SBP or CNNA, the clinical and laboratory data showed no significant difference between the symptomatic and asymptomatic groups. In contrast, among the patients with BA, the symptomatic group had significantly higher levels of serum total bilirubin and prolonged prothrombin time and significantly lower levels of ascitic fluid total protein than the asymptomatic group. Furthermore, the clinical and laboratory data were relatively similar between patients with asymptomatic BA and those with sterile ascites. In contrast, patients with SBP, CNNA, or symptomatic BA exhibited significantly more severe degrees of liver disease and significantly lower levels of ascitic fluid total protein than those with sterile ascites. There was no statistically significant difference between SBP and bacterascites regarding flora. All patients with SBP, CNNA, or symptomatic BA received antibiotic treatment immediately after paracentesis, as did six of the 14 patients with asymptomatic BA for concurrent respiratory or urinary tract infection, while the remaining eight patients with asymptomatic BA were followed clinically without treatment. Repeated paracentesis in the latter revealed no evidence of SBP or CNNA. The in-hospital mortality for sterile ascites was 22.8%, significantly lower than the 54.5% for SBP, 43.2% for CNNA, and 50% for symptomatic BA, but similar to the 21.4% for asymptomatic BA.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Q fever hepatitis in Taiwan

We report a case of a chronic hepatitis B carrier with an episode of acute hepatitis. The patient presented with a headache, arthralgias, jaundice and fever. While the laboratory tests mimicked chronic hepatitis B with an acute exacerbation, lipogranulomatous changes seen in the liver biopsy strongly suggested the presence of Q fever. Serology testing for Coxiella burneti proved positive and the patient responded to tetracycline therapy. While previously unreported in Taiwan, Q fever is important to consider in an atypical hepatitis presentation because it is a treatable condition.

Characterization of a "kissing" hairpin complex derived from the human immunodeficiency virus genome

Base-pair formation between two hairpin loops--a "kissing" complex--is an RNA-folding motif that links two elements of RNA secondary structure. It is also a unique protein recognition site involved in regulation of ColE1 plasmid DNA replication. The trans-activation response element (TAR), a hairpin and bulge at the 5' end of the untranslated leader region of the human immunodeficiency virus 1 mRNA, enhances the transcription of the virus and is necessary for viral replication. Gel electrophoresis and absorbance melting curves indicate that a synthesized RNA hairpin (Tar*-16) with a loop sequence complementary to the TAR loop sequence (CUGGGA) associates specifically with a 16-nucleotide TAR hairpin (Tar-16) to form a stable complex. RNase T1 probing indicates that the three guanines in the Tar-16 loop become inaccessible in the complex. NMR imino proton spectra reveal that 5 base pairs are formed between the two hairpin loops (Tar-16 and Tar*-16); only the adenine at the 3' terminus of the TAR loop does not form a base pair with the 5'-terminal uracil of the complementary loop. A 14-nucleotide hairpin [CCUA(UCCCAG)UAGG] with a loop sequence complementary to the TAR loop is conserved within the gag gene of human immunodeficiency virus 1. A synthesized RNA hairpin corresponding to this conserved sequence also binds to the Tar-16 hairpin with high affinity. It is possible that the same RNA loop-loop interaction occurs during the viral life cycle.

Vibration induced neurophysiological and electron microscopical changes in rat peripheral nerves

This study was conducted to clarify the effects of vibration on the peripheral nerves. Rat tails were exposed to vibration (acceleration 56.9 m/s2, frequency 60 Hz, amplitude 0.4 mm for two or four hours daily, six days a week. The maximum motor conduction velocity (MCV), the amplitude of evoked response, and the motor distal latency were measured on rat tail nerves every two months. Thin sections of tail nerves were examined under the electron microscope after 200, 500, and 800 hours of vibration. Neurophysiological and ultrastructural changes in tail nerves increased with the dose of vibration. In the groups exposed to vibration the MCVs were significantly reduced after a vibration time up to 400 hours, whereas the motor distal latency was not delayed significantly until 600 vibration hours. The ultrastructural changes were (1) detachment of the myelin sheath from the axolemma, (2) constriction of the axon, (3) protrusion of the myelin sheath into the axon, (4) accumulation of vacuoles in paranodal regions, and (5) dilatation of the Schmidt-Lanterman incisures. The ultrastructural changes induced by vibration in the paranodal regions and myelin sheaths were possibly responsible for the reduction in MCVs.

Regioselective enzymic deacetylation of octa-O-acetylsucrose: preparation of hepta-O-acetylsucroses

Deacetylation of octa-O-acetylsucrose (1) with Alcalase or protease N gave the 2,3,4,6,3',4',6'-hepta-acetate (2) as the initial major product with the 2,3,4,6,3',4'-hexa-acetate (3) as the subsequent main product. The 2,3,4,1',3',4',6'-hepta-acetate (5) was obtained from 1 by the action of lipase OF or lipase AP6, and the 2,3,4,6,1',3',6'-(4) and 2,3,4,6,1',3',4'-hepta-acetate (7) by the action of Candida lipase and chymotrypsin, respectively. The 2,3,6,1',3',4',6'-hepta-acetate (6) was formed from 5 by acyl migration.