Thickness of rectus abdominis measured by ultrasound in critically ill patients after abdominal surgery: A retrospective cohort study

BACKGROUND

Early identification of patients at high risk of prolonged mechanical ventilation is important in critical care. Sarcopenia, the loss of muscle mass and function, has been reported to be associated with extended mechanical ventilation and prolonged ICU stay. Although ultrasound is noninvasive and widely used in critical care, there is no standard method of using it to assess sarcopenia.

OBJECTIVES

The study aims to investigate the relationship between outcomes of critically ill patients and the ratio of BMI to the thickness of rectus abdominis measured by a standardised ultrasound examination.

DESIGN

A retrospective cohort study.

SETTING

Surgical ICU of a tertiary referral hospital, from October 2017 to June 2018. The thickness of rectus abdominis (RA) was measured while performing extended focused assessment sonography for trauma. BMI was divided by the thickness of rectus abdominis over the upper abdomen to derive the BMI-RA thickness ratio.

PATIENTS

Sixteen male and 11 female patients admitted to ICU after major abdominal surgery.

MAIN OUTCOME MEASURES

The primary outcome was in-hospital mortality, and the secondary outcomes were durations of mechanical ventilation, ICU stay and hospital stay. The disease severity, serum albumin level and BMI-RA thickness ratio were also analysed.

RESULTS

Ultrasound measurement was easy to perform without adverse effects. The BMI-RA thickness ratio was significantly higher in nonsurvivors and was associated with ICU stay, hospital stay and duration of mechanical ventilation. Multivariable logistic regression showed that the BMI-RA thickness ratio was a predictor of in-hospital mortality.

CONCLUSION

The BMI-RA thickness ratio is related to the outcomes of patients transferred to ICU after major abdominal surgery. Measuring the thickness of rectus abdominis by ultrasound is well tolerated and easy to perform in surgical ICU. Larger prospective studies are required to confirm current findings.

Lactobacillus salivarius reverse antibiotic-induced lung defense impairment in a ventilator model

Background

Widespread use of antibiotics in the intensive care unit is a potential cause of the emergence of hospital-acquired pneumonia. This study determined whether Lactobacillus salivarius feeding could reverse antibiotic-induced lung defense impairment in a ventilator model.

Methods

C57BL/6 wild-type (WT) mice received mechanical ventilation for 3 h after intramuscular antibiotic treatment for 6 days. Treatment with dead Lactobacillus salivarius and fructo-oligosaccharides (FOS) feeding were used to stimulate antibacterial protein expression in the intestine. Reactive oxygen species (ROS) in the intestinal mucosa was detected using 2ʹ7ʹ-dichlorofluorescein diacetate. The peroxynitrite production of alveolar macrophages (AMs) was measured using dihydrorhodamine 123 oxidation assay. N-acetylcysteine (NAC), an ROS scavenger, was orally administered to mice receiving antibiotics with FOS feeding.

Results

Antibiotic treatment decreased Pseudomonas aeruginosa (PA) phagocytic activity and activity of AMs and protein expression of regenerating islet-derived protein 3β (Reg3β) as well as Toll-like receptor 4 (TLR4) in the intestinal mucosa in the ventilator model. Antibiotic treatment also decreased ROS production in the intestinal mucosa, peroxynitrite production of AMs, and RELMβ expression as well as NF-κB DNA binding activity of the intestinal mucosa in WT mice but not in MyD88^−/− mice. Treatment with dead L. salivarius or FOS feeding increased ROS production, bacterial killing activity, and protein expression of Reg3β as well as TLR4 in the intestinal mucosa and reversed the inhibitory effects of antibiotics on PA phagocytic activity of AMs.

Conclusion

Taken together with the finding that ablation of FOS-induced intestinal ROS using NAC decreased peroxynitrite production as well as PA phagocytic activity of AMs and protein expression of CRP-ductin, IL-17, Reg3β, and RELMβ in the intestinal mucosa, we conclude that commensal microflora plays a key role in stimulating lung immunity. Intestinal ROS plays a role as a predictive indicator and modulator of pulmonary defense mechanisms. Antibiotic treatment reduces lung defense against PA infection through the decrease in intestinal Reg3β and TLR4 expression. Treatment with dead L. salivarius or FOS feeding reverses the antibiotic-induced lung defense impairment through the intestinal ROS/MyD88 pathways.

Lactobacillus plantarum reverse diabetes-induced Fmo3 and ICAM expression in mice through enteric dysbiosis-related c-Jun NH2-terminal kinase pathways

Diabetes mellitus (DM) is characterized by increased fatality associated with the atherogenetic process. Circulating trimethylamine-N-oxide (TMAO) levels are closely associated with atherosclerosis. The flavin mono-oxygenase family (Fmo) members oxidize trimethylamine (TMA) to TMAO. The effect and the regulatory mechanism of intestinal microflora on diabetes-induced Fmo3 and intercellular adhesion molecule (ICAM) expression were examined in streptozotocin-induced diabetic mice (STZDM) and Akita mice (C57BL/6J-Ins2^Akita). STZDM-JNK1^-/- and Ins2^Akita-JNK1^-/- mice were produced and used to study the role of pJNK in the regulatory mechanisms. Diabetic mice exhibited decreased Lactobacilli growth and reactive oxygen species (ROS) production in the intestinal mucosa; increased levels of pJNK and iNOS proteins in the intestinal mucosa; increased levels of serum nitrate, IL-1β, and TNF-α expression in Kupffer cells; increased Fmo3 expression in the liver; and increased ICAM expression in the aorta. Reversal of diabetes-induced enteric dysbiosis by prebiotic (FOS) or probiotic (dead L. plantarum) treatment decreased diabetes-induced pJNK and iNOS expression in the intestine, Fmo3 expression in the liver, IL-1β expression in Kupffer cells, and ICAM expression in the aorta and liver. Ins2^Akita-JNK1^-/- and STZDM-JNK1^-/- mice demonstrated decreased levels of serum NO, IL-1β expression in Kupffer cells, Fmo3 expression in the liver, and ICAM expression in the aorta. GF mice cohoused with DM mice demonstrated an increase in ICAM expression in the liver. In conclusion, diabetes induced the expression of both Fmo3 and ICAM expression and possible vascular impairment through enteric dysbiosis. Diabetes-induced Fmo3 and ICAM expression could be reversed by pJNK inhibition or by correcting enteric dysbiosis.

Integration of Oncogenes via Sleeping Beauty as a Mouse Model of HPV16+ Oral Tumors and Immunologic Control

Human papillomavirus type 16 (HPV16) is the etiologic factor for cervical cancer and a subset of oropharyngeal cancers. Although several prophylactic HPV vaccines are available, no effective therapeutic strategies to control active HPV diseases exist. Tumor implantation models are traditionally used to study HPV-associated buccal tumors. However, they fail to address precancerous phases of disease progression and display tumor microenvironments distinct from those observed in patients. Previously, K14-E6/E7 transgenic mouse models have been used to generate spontaneous tumors. However, the rate of tumor formation is inconsistent, and the host often develops immune tolerance to the viral oncoproteins. We developed a preclinical, spontaneous, HPV16⁺ buccal tumor model using submucosal injection of oncogenic plasmids expressing HPV16-E6/E7, NRas ^G12V , luciferase, and sleeping beauty (SB) transposase, followed by electroporation in the buccal mucosa. We evaluated responses to immunization with a pNGVL4a-CRT/E7(detox) therapeutic HPV DNA vaccine and tumor cell migration to distant locations. Mice transfected with plasmids encoding HPV16-E6/E7, NRas ^G12V , luciferase, and SB transposase developed tumors within 3 weeks. We also found transient anti-CD3 administration is required to generate tumors in immunocompetent mice. Bioluminescence signals from luciferase correlated strongly with tumor growth, and tumors expressed HPV16-associated markers. We showed that pNGVL4a-CRT/E7(detox) administration resulted in antitumor immunity in tumor-bearing mice. Lastly, we demonstrated that the generated tumor could migrate to tumor-draining lymph nodes. Our model provides an efficient method to induce spontaneous HPV⁺ tumor formation, which can be used to identify effective therapeutic interventions, analyze tumor migration, and conduct tumor biology research. Cancer Immunol Res; 6(3); 305-19. ©2018 AACR.

Buccal injection of synthetic HPV long peptide vaccine induces local and systemic antigen-specific CD8+ T-cell immune responses and antitumor effects without adjuvant

BACKGROUND

Human Papillomavirus is responsible for over 99 % of cervical cancers and is associated with cancers of the head and neck. The currently available prophylactic vaccines against HPV do not generate therapeutic effects against established HPV infections and associated lesions and disease. Thus, the need for a therapeutic vaccine capable of treating HPV-induced malignancies persists. Synthetic long peptides vaccination is a popular antigen delivery method because of its safety, stability, production feasibility, and its need to be processed by professional antigen presenting cells before it can be presented to cytotoxic CD8+ T lymphocytes. Cancers in the buccal mucosa have been shown to elicit cancer-related inflammations that are capable of recruiting inflammatory and immune cells to generate antitumor effects. In the current study, we evaluated the therapeutic potential of synthetic HPV long peptide vaccination in the absence of adjuvant in the TC-1 buccal tumor model.

RESULT

We show that intratumoral vaccination with E7 long peptide alone effectively controls buccal TC-1 tumors in mice. Furthermore, we observed an increase in systemic as well as local E7-specific CD8+ T cells in buccal tumor-bearing mice following the vaccination. Finally, we show that induction of immune responses against buccal tumors by intratumoral E7 long peptide vaccination is independent of CD4+ T cells, and that the phenomenon may be related to the unique environment associated with mucosal tissues.

CONCLUSION

Our results suggest the possibility for clinical translation of the administration of adjuvant free therapeutic long peptide vaccine as a potentially effective and safe strategy for mucosal HPV-associated tumor treatment.

Cancer immunotherapy using a potent immunodominant CTL epitope

Immunotherapy has emerged as a promising approach that can be used in conjunction with conventional chemotherapy and radiotherapy to further improve the survival rate of patients with advanced cancer. We have recently shown in previous studies that chemotherapy and radiation therapy can alter the tumor microenvironment and allow intratumoral vaccination to prime the adaptive immune system leading to the generation of antigen-specific cell-mediated immune responses. Here, we investigated whether intratumoral injection of a foreign immunodominant peptide (GP33) and the adjuvant CpG into tumors following cisplatin chemotherapy could lead to potent antitumor effects and antigen-specific cell-mediated immune responses. We observed that treatment with all three agents produced the most potent antitumor effects compared to pairwise combinations. Moreover, treatment with cisplatin, CpG and GP33 was able to control tumors at a distant site, indicating that our approach is able to induce cross-presentation of the tumor antigen. Treatment with cisplatin, CpG and GP33 also enhanced the generation of GP33-specific and E7-specific CD8+ T cells and decreased the number of MDSCs in tumor loci, a process found to be mediated by the Fas-FasL apoptosis pathway. The treatment regimen presented here represents a universal approach to cancer control.

NF-κB activation in myeloid cells mediates ventilator-induced lung injury

Background

Although use of the mechanical ventilator is a life-saving intervention, excessive tidal volumes will activate NF-κB in the lung with subsequent induction of lung edema formation, neutrophil infiltration and proinflammatory cytokine/chemokine release. The roles of NF-κB and IL-6 in ventilator-induced lung injury (VILI) remain widely debated.

Methods

To study the molecular mechanisms of the pathogenesis of VILI, mice with a deletion of IкB kinase in the myeloid cells (IKKβ^△mye), IL-6^-/- to WT chimeric mice, and C57BL/6 mice (WT) were placed on a ventilator for 6 hr.

WT mice were also given an IL-6-blocking antibody to examine the role of IL-6 in VILI.

Results

Our results revealed that high tidal volume ventilation induced pulmonary capillary permeability, neutrophil sequestration, macrophage drifting as well as increased protein in bronchoalveolar lavage fluid (BALF). IL-6 production and IL-1β, CXCR2, and MIP2 expression were also increased in WT lungs but not in those pretreated with IL-6-blocking antibodies. Further, ventilator-induced protein concentrations and total cells in BALF, as well as lung permeability, were all significantly decreased in IKKβ^△mye mice as well as in IL6^-/- to WT chimeric mice.

Conclusion

Given that IKKβ^△mye mice demonstrated a significant decrease in ventilator-induced IL-6 production, we conclude that NF-κB–IL-6 signaling pathways induce inflammation, contributing to VILI, and IкB kinase in the myeloid cells mediates ventilator-induced IL-6 production, inflammation, and lung injury.

Blocking TNF-α enhances Pseudomonas aeruginosa-induced mortality in burn mice through induction of IL-1β

PURPOSE

Tumor necrosis factor (TNFα) is a proinflammatory cytokine and has been a target for intervention in human sepsis. However, inhibition of TNF-α with a high dose of a TNF-receptor fusion protein in patients with septic shock worsened patient survival. This study was designed to investigate whether blocking TNF-α enhances mortality in infected burn mice through the induction of IL-1β.

METHODS

WT or Tnfrsf1a(-/-) mice received Pseudomonas aeruginosa injection in the back at 8h after burn injury. The animals were sacrificed at 24h after burn and lung tissues were harvested and examined for determining myeloperoxidase (MPO) activity, pulmonary microvascular dysfunction, NF-κB DNA binding activity, and IL-1β expression. Also, the lung and blood were harvested for bacterial count assay.

RESULT

Thermal injury alone induced NF-κB DNA binding activity and neutrophil infiltration in the lung in WT but not in Tnfrsf1a(-/-) mice. A 50% total body surface area (TBSA) burn induced a significant increase of mortality in WT compared with Tnfrsf1a(-/-) mice. In contrast, P. aeruginosa injection with a 30% TBSA burn pretreatment enhanced IL-1β expression, bacterial counts in lung and blood, pulmonary microvascular dysfunction, and mortality in Tnfrsf1a(-/-) mice compared with WT mice. Injection of the IL-1 receptor antagonist, Anakinra, reduced P. aeruginosa infection with burn pretreatment-induced blood bacterial counts, IL-1β levels as well as permeability of lung, and mortality in Tnfrsf1a(-/-) mice.

CONCLUSIONS

Our findings suggest that thermal injury induces lung NF-κB activation and neutrophil sequestration through TNFα signaling. However, blocking TNF-α enhances P. aeruginosa infection-induced lung damage in burn mice via induction of IL-1β. Using an IL-1 receptor antagonist combined with the neutralization of TNF-α could be a useful strategy for decreasing P. aeruginosa infection-induced mortality in burn patients.

Gut flora enhance bacterial clearance in lung through toll-like receptors 4

Background

The influence of the gut flora on lung inflammatory reaction against bacterial challenge remains undefined. This study was designed to investigate whether gut flora enhances lung defense against E.coli pneumonia through TLR4 signaling.

Methods

C3H/HeN (WT) mice and C3H/HeJ (TLR4 deficient) mice were treated with antibiotics in drinking water for 4 weeks to deplete gut commensal microflora. At week 3, drinking water was supplemented with lipopolysaccharide (LPS); a ligand for TLR4, to trigger TLRs in intestinal tract. At the end of 4^th week, E.coli was injected to trachea to induce E.coli pneumonia.

Results

We found that commensal depletion by antibiotic pretreatment before E.coli pneumonia challenge induced a 30% decrease of MPO activity in the lung, a significant decrease of bacterial killing activity of alveolar macrophage, and bacterial counts in C3H/HeN mice but not in C3H/HeJ (TLR4 deficient) mice. LPS, a TLR4 ligand, supplementation during antibiotic pretreatment reversed these effects and decreased E.coli pneumonia-induced mortality in C3H/HeN mice. Furthermore, commensal depletion induced a suppression of NF-κB DNA binding activity and an increase of KC, MIP-2, IL-1β expression in the lung in C3H/HeN mice but not in C3H/HeJ mice.

Conclusions

Taken together with that commensal depletion increased E.coli pneumonia-induced mortality and LPS supplementation decreased it, we conclude that gut flora enhances bacterial clearance against E.coli pneumonia through TLR4.

Phase contribution of image potential on empty quantum well States in pb islands on the cu(111) surface

We use scanning tunneling spectroscopy to explore the quantum well states in the Pb islands grown on a Cu(111) surface. Our observation demonstrates that the empty quantum well states, whose energy levels lie beyond 1.2 eV above the Fermi level, are significantly affected by the image potential. As the quantum number increases, the energy separation between adjacent states is shrinking rather than widening, contrary to the prediction for a square potential well. By simply introducing a phase factor to reckon the effect of the image potential, the shrinking behavior of the energy separation can be reasonably explained with the phase accumulation model. The model also reveals that there exists a quantum regime above the Pb surface in which the image potential is vanished. Moreover, the quasi-image-potential state in the tunneling gap is quenched because of the existence of the quantum well states.

Factors influencing the successful treatment of infectious pulmonary tuberculosis

SETTING

Achieving successful treatment of infectious pulmonary tuberculosis (PTB) could reduce the spread of tuberculosis (TB) and the emergence of multidrug resistance.

OBJECTIVE

To explore factors associated with successful treatment for sputum-positive PTB.

DESIGN

This study used a population-based retrospective cohort design. All PTB patients residing in southern Taiwan recorded in the tuberculosis registry from 1 January to 30 June 2003 were identified. Each patient's medical record was requested from treating hospitals and retrospectively reviewed for 15 months after the date PTB was confirmed.

RESULTS

There were 399 PTB patients included in the study. Factors significantly associated with successful treatment included treatment by pulmonologists (OR 1.93), receiving directly observed therapy (DOT) (OR 1.76) and receiving treatment at the chest hospital (OR 5.41). Patients of advanced age were less likely to achieve treatment success (OR 0.97). Among patients treated by pulmonologists, those treated at the chest hospital had a significantly higher treatment success rate than those treated at other institutions (94.1% vs. 69.9%).

CONCLUSIONS

Patients treated with DOT and by pulmonologists, especially at the chest hospital, had a higher treatment success rate. DOT and training of care professionals and institutions are therefore important factors that affect the successful treatment of TB.

A Novel Conformation-Dependent Monoclonal Antibody Specific to the Native Structure of β-Lactoglobulin and Its Application

Molten globules are thought to be general intermediates in protein folding and unfolding. beta-lactoglobulin (beta-LG) is one of the major bovine whey proteins, constituting approximately 10 to 15% of total milk proteins. We have recently identified beta-LG as a superior marker for evaluating thermally processed milk. Strand D of beta-LG participates in irreversible thermal unfolding as probed by a monoclonal antibody (mAb) specific to thermally denatured beta-LG. In the present study, we used native beta-LG as an immunogen to test the hypothesis that a specific mAb against the native beta-LG could be established. As result, a mAb (4H11E8) directed against the native structure of beta-LG was made. The antibody did not recognize the heat-denatured form of beta-LG, such as its dimer and aggregates. Immunoassay using this "native" mAb showed that the stability of beta-LG was at temperatures < or =70 degrees C. beta-Lactoglobulin began to deteriorate between 70 and 80 degrees C over time. The denaturation was correlated with the transition temperature of beta-LG. Further chemical modification of Cys (carboxymethylation) or positively charged residues (acetylation) of beta-LG totally abolished its immunoreactivity, confirming the conformation-dependent nature of this mAb. Using competitive ELISA, the 4H11E8 mAb could determine the native beta-LG content in commercially processed milks. Concentrations of native beta-LG varied significantly among the local brands tested. From a technological standpoint, the mAb prepared in this study is relevant to the design and operation of appropriate processes for thermal sanitation of milk and of other dairy products.

Smoking attributable medical expenditures, years of potential life lost, and the cost of premature death in Taiwan

OBJECTIVE

To estimate the smoking attributable medical expenditures and productivity loss of people aged 35 and over in Taiwan in 2001 from a societal viewpoint.

METHODS

A prevalence based approach was used to estimate smoking attributable costs. Epidemiological parameters were obtained from two follow up studies and government statistics. Data on medical care utilisation and expenditure were extracted from the National Health Insurance claim data.

RESULTS

Total smoking attributable medical expenditures (SAEs) amounted to USD 397.6 million, which accounted for 6.8% of the total medical expenditures for people aged 35 and over. Mean annual medical expenditures per smoker was USD 70 more than that of each non-smoker. Smoking attributable years of potential life lost (YPLL) totalled to 217,761 years for males and 15,462 years for females, and the corresponding productivity loss was USD 1371 million for males and USD 18.7 million for females.

CONCLUSION

Medical expenditures attributable to smoking accounted for 6.8% of the total medical expenditure of people aged 35 and over for the year 2001 in Taiwan. Corresponding YPLL and productivity loss also demand that actions be taken to fight cigarette smoking.

Acute mediastinitis resulting from an unsuspected fish bone--case report

Acute mediastinitis is a serious medical condition with a mortality rate from 30 to 40% or even higher. Early diagnosis with prompt and aggressive treatment is essential to prevent its rapid progression. Severe odynophagia and respiratory distress with positive neck or chest findings should raise suspicion of mediastinitis. We report a rare case of acute mediastinitis secondary to the unexpected migration of an impacted fish bone from the esophagus.

The use of air fuel cell cathodes to remove contaminants from spent chromium plating solutions

Results from experiments using an impregnation-reduction (I-R) Pt / Nafion membrane electrode assembly (MEA) in an air fuel cell cathode to remove contaminants (Cu(II), Ni(II), and Fe(III)) from spent chromium electroplating baths are presented in this study. A platinum-carbon (Pt-C) / Nafion MEA and a Pb planar cathode were also used for comparison. The average removal rates of Cu(II) and Ni(II) were almost the same (0.39 and 0.40 mM hr(-1) (or 0.117 and 0.12 mmol hr(-1)), respectively) but higher than that of Fe(III) (0.16 mM hr(-1), or 0.048 mmol hr(-1)) in accordance with the Nernst-Planck flux equation. The removal rates for the same cation were independent of the cathode used. The average removal rate of each impurity was approximately proportional to the product of its initial concentration and separator area/anolyte volume ratio using Pb cathodes. Under constant current conditions the system using the Pt-C / Nafion cathode needed the highest cell voltage, about 3 V more than needed for the system with the Pt / Nafion cathode. The cell voltage required using the Pt / Nafion cathode was similar to that using the conventional planar Pb cathode. Analyses of cathode deposits by SEM/EDS and XPS techniques indicated they were minimal on the Pb and Pt / Nafion cathode and more apparent on the Pt-C / Nafion cathode. The primary deposits on the Pb cathode were chromium oxides (e.g., Cr2O3) with minor amount of lead chromate (lead dichromate or lead trichromate) and other chromium solids (Cr black). As expected, the dominant deposit on the lead anode surface was PbO2.

Protein adsorption, fibroblast activity and antibacterial properties of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) grafted with chitosan and chitooligosaccharide after immobilized with hyaluronic acid

Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) membrane was treated with ozone and grafted with acrylic acid. The resulting membranes were further grafted with chitosan (CS) or chitooligosaccharide (COS) via esterification. Afterward hyaluronic acid (HA) was immobilized onto CS- or COS-grafting membranes. The antibacterial activity of CS and COS against Staphylococus aureus, Escherichia coli, and Pseudomonas aeruginosa was preserved after HA immobilization. Among them, CS-grafted PHBV membrane showed higher antibacterial activity than COS-grafted PHBV membrane. In addition, after CS- or COS-grafting, the L929 fibroblasts attachment and protein adsorption were improved, while the cell number was decrease. After immobilizing HA, the cell proliferation was promoted, the protein adsorption was decreased, and the cell attachment was slightly lower than CS- or COS-grafting PHBV.

Cell membrane transport of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the liver and systemic bioavailability

Modulation of hepatic disposition of MPTP could influence susceptibility to its neurotoxicity. Therefore, we studied hepatocellular transport of MPTP in the perfused rat liver and isolated rat hepatocytes. The perfused liver extensively extracted MPTP. Amiloride and tubocurarine, inhibitors of OCT1, increased MPTP recovery (253 +/- 78 and 283 +/- 64%, respectively) and reduced PS(influx) (0.69 +/- 0.36 to 0.27 +/- 0.11, and 0.97 +/- 0.50 to 0.23 +/- 0.05 ml/s/g, respectively). P-glycoprotein inhibitor, daunomycin, and Oatp 1 & 2 inhibitor, rifamycin, had no effect. In isolated hepatocytes, amiloride and tubocurarine increased hepatic uptake of MPTP (23 +/- 12 and 6 +/- 2%, respectively). Daunomycin reduced MPTP uptake by 22 +/- 8% and rifamycin had no effect. Only a small proportion of MPTP is taken up into hepatocytes by transporters; however, modulation of these transport mechanisms will influence systemic bioavailability.

A multivalent pairing model of linkage analysis in autotetraploids

Polyploidy has been recognized as an important step in the evolutionary diversification of flowering plants and may have a significant impact on plant breeding. Statistical analyses for linkage mapping in polyploid species can be difficult due to considerable complexities in polysomic inheritance. In this article, we develop a novel statistical method for linkage analysis of polymorphic markers in a full-sib family of autotetraploids. This method is established on multivalent pairings of homologous chromosomes at meiosis and can provide a simultaneous maximum-likelihood estimation of the double reduction frequencies of and recombination fraction between two markers. The EM algorithm is implemented to provide a tractable way for estimating relative proportions of different modes of gamete formation that generate identical gamete genotypes due to multivalent pairings. Extensive simulation studies were performed to demonstrate the statistical properties of this method. The implications of the new method for understanding the genome structure and organization of polyploid species are discussed.

A statistical method for flagging weak spots improves normalization and ratio estimates in microarrays

Over the last few years, there has been a dramatic increase in the use of cDNA microarrays to monitor gene expression changes in biological systems. Data from these experiments are usually transformed into expression ratios between experimental samples and a common reference sample for subsequent data analysis. The accuracy of this critical transformation depends on two major parameters: the signal intensities and the normalization of the experiment vs. reference signal intensities. Here we describe and validate a new model for microarray signal intensity that has one multiplicative variation and one additive background variation. Using replicative experiments and simulated data, we found that the signal intensity is the most critical parameter that influences the performance of normalization, accuracy of ratio estimates, reproducibility, specificity, and sensitivity of microarray experiments. Therefore, we developed a statistical procedure to flag spots with weak signal intensity based on the standard deviation (delta(ij)) of background differences between a spot and the neighboring spots, i.e., a spot is considered as too weak if the signal is weaker than cdelta(ij). Our studies suggest that normalization and ratio estimates were unacceptable when this threshold (c) is small. We further showed that when a reasonable compromise of c (c = 6) is applied, normalization using trimmed mean of log ratios performed slightly better than global intensity and mean of ratios. These studies suggest that decreasing the background noise is critical to improve the quality of microarray experiments.

Cytological evidence for association of the ends of the linear chromosome in Streptomyces coelicolor

The chromosome of the filamentous bacterium Streptomyces coelicolor is linear, but the genetic map is circular. We present cytological evidence based on the use of fluorescence in situ hybridization showing that the ends of the chromosome frequently colocalize, in agreement with the idea that the ends are held together, effectively forming a circular chromosome. These observations provide a possible explanation for how a linear bacterial chromosome can exhibit a circular genetic map.

Clinical wear performance of eight experimental dental composites over three years determined by two measuring methods

The effect of matrix selection, filler composition, filler silanization, operator variations, and test site (dental clinic) on the wear rate of eight composites were evaluated. The wear was measured on replicas using both a microscopic and a laser scanning measuring method. The average wear rate on contact-free surfaces was 9.2 +/- 4.2 microm/month with the microscopic measurement and 8.5 +/- 3.7 microm/ month with the laser scanner over the 36-month period. The urethane-based composites performed significantly better than those which were bisGMA-based. Restorations placed at one dental clinic showed significantly lower initial wear. There was also a significant difference between the operators that was most pronounced during the first 6 months. The other variable (filler composition and silane treatment) did not affect the wear rate significantly.

Forkhead homologue in rhabdomyosarcoma functions as a bifunctional nuclear receptor-interacting protein with both coactivator and corepressor functions

In a search for novel transcriptional intermediary factors for the estrogen receptor (ER), we used the ligand-binding domain and hinge region of ER as bait in a yeast two-hybrid screen of a cDNA library derived from tamoxifen-resistant MCF-7 human breast tumors from an in vivo athymic nude mouse model. Here we report the isolation and characterization of the forkhead homologue in rhabdomyosarcoma (FKHR), a recently described member of the hepatocyte nuclear factor 3/forkhead homeotic gene family, as a nuclear hormone receptor (NR) intermediary protein. FKHR interacts with both steroid and nonsteroid NRs, although the effect of ligand on this interaction varies by receptor type. The interaction of FKHR with ER is enhanced by estrogen, whereas its interaction with thyroid hormone receptor and retinoic acid receptor is ligand-independent. In addition, FKHR differentially regulates the transactivation mediated by different NRs. Transient transfection of FKHR into mammalian cells dramatically represses transcription mediated by the ER, glucocorticoid receptor, and progesterone receptor. In contrast, FKHR stimulates rather than represses retinoic acid receptor- and thyroid hormone receptor-mediated transactivation. Most intriguingly, overexpression of FKHR dramatically inhibits the proliferation of ER-dependent MCF-7 breast cancer cells. Therefore, FKHR represents a bifunctional NR intermediary protein that can act as either a coactivator or corepressor, depending on the receptor type.

A localized GTPase exchange factor, Bud5, determines the orientation of division axes in yeast

GTPases are widespread in directing cytoskeletal rearrangements and affecting cellular organization. How they do so is not well understood. Yeast cells divide by budding, which occurs in two spatially programmed patterns, axial or bipolar [1-3]. Cytoskeletal polarization to form a bud is governed by the Ras-like GTPase, Bud1/Rsr1, in response to cortical landmarks. Bud1 is uniformly distributed on the plasma membrane, so presumably its regulators, Bud5 GTPase exchange factor and Bud2 GTPase activating protein, impart spatial specificity to Bud1 action [4]. We examined the localizations of Bud5 and Bud2. Both Bud1 regulators associate with cortical landmarks designating former division sites. In haploids, Bud5 forms double rings that encircle the mother-bud neck and split upon cytokinesis so that each progeny cell inherits Bud5 at the axial division remnant. Recruitment of Bud5 into these structures depends on known axial landmark components. In cells undergoing bipolar budding, Bud5 associates with multiple sites, in response to the bipolar landmarks. Like Bud5, Bud2 associates with the axial division remnant, but rather than being inherited, Bud2 transiently associates with the remnant in late G1, before condensing into a patch at the incipient bud site. The relative timing of Bud5 and Bud2 localizations suggests that both regulators contribute to the spatially specific control of Bud1 GTPase.

Urea permeation and hydrolysis through hollow fiber dialyzer immobilized with urease

The surface of commercial polyacrylonitrile hollow fibers was hydrolyzed and covalently bonded with urease by using glutaraldehyde. Mini-modules assembled with these modified hollow fibers were then used to study the effect of concentration of glutaraldehyde, pH, and temperature on the catalysis of urea. The immobilized amount increased with the concentration of glutaraldehyde. However, urease immobilized with 5% glutaraldehyde had higher activity (0.38 micromol/min/mg-urease) than with other concentrations. The activity of the immobilized urease remained at above 0.32 micromol/min/mg-urease over wider applicable ranges of temperature (4-70 degreesC) and pH (5-8) compared to free urease. For comparison, the activity of immobilized urease was 0.35 micromol/min/mg-urease, while that for non-immobilized urease was 0.33 micromol/min/mg-urease at pH 7 and 20 degreesC. The removal of urea using urease-immobilized dialyzer was demonstrated with in-vitro dialysis and showed faster removing rate of urea than a regular dialyzer by 2.7 times.

Fracture resistance of all-ceramic and metal-ceramic inlays

PURPOSE

Metal-ceramic inlay designs were developed to determine if the esthetic qualities of all-ceramic inlays could be duplicated and at the same time improve their strength and stability. The objectives of this study were to: (1) compare the fracture resistance of metal-ceramic inlays with that of all-ceramic inlays; (2) determine the correlation between the degree of preparation taper and fracture resistance; and (3) determine the correlation between marginal gap width and fracture resistance.

MATERIALS AND METHODS

Inlay preparations were made on 60 Dentoform teeth, with 30 teeth allocated for metal-ceramic inlays and 30 teeth for all-ceramic inlays. Each group was further subdivided into 5-, 10-, and 20-degree taper preparations. Metal-ceramic inlays were fabricated using Goldtech Bio 2000 metal and Ceramco porcelain extending to the margin, while all-ceramic inlays were made from Empress II ceramic. Marginal gap widths were measured at six critical areas after fabrication. The load at failure was measured using an Instron Universal Testing Machine.

RESULTS

The mean fracture load for all-ceramic inlays and metal-ceramic inlays at 5, 10, and 20 degrees was 70+/-40 N, 48+/-37 N, 33+/-7 N, and 40+/-23 N, 29+/-22 N, and 14+/-4 N, respectively. The mean gap width was 105 microm and 126 microm for all-ceramic and metal-ceramic inlays, respectively.

CONCLUSION

The mean fracture load for Empress inlays was significantly higher than that for metal-ceramic inlays. Inlays with a 5-degree taper were significantly more fracture resistant than those with a 20-degree taper. There was no relation between marginal gap width and fracture resistance.

Comparison of diameter and perimeter methods for tumor volume calculation

PURPOSE

Lesion volume is often used as an end point in clinical trials of oncology therapy. We sought to compare the common method of using orthogonal diameters to estimate lesion volume (the diameter method) with a computer-assisted planimetric technique (the perimeter method).

METHODS

Radiologists reviewed 825 magnetic resonance imaging studies from 219 patients with glioblastoma multiforme. Each study had lesion volume independently estimated via the diameter and perimeter methods. Cystic areas were subtracted out or excluded from the outlined lesion. Inter- and intrareader variability was measured by using multiple readings on 48 cases. Where serial studies were available in noncystic cases, a mock response analysis was used.

RESULTS

The perimeter method had a reduced interreader and intrareader variability compared with the diameter method (using SD of differences): intrareader, 1.76 mL v 7.38 mL (P < .001); interreader, 2.51 mL v 9.07 mL (P < .001) for perimeter and diameter results, respectively. Of the 121 noncystic cases, 23 had serial data. In six (26.1%) of those 23, a classification difference occurred when the perimeter method was used versus the diameter method.

CONCLUSION

Variability of measurements was reduced with the computer-assisted perimeter method compared with the diameter method, which suggests that changes in volume can be detected more accurately with the perimeter method. The differences between these techniques seem large enough to have an impact on grading the response to therapy.

Evidence that silencing of the HPRT promoter by DNA methylation is mediated by critical CpG sites

The strong correlation between promoter hypermethylation and gene silencing suggests that promoter methylation represses transcription. To identify methylation sites that may be critical for maintaining repression of the human HPRT gene, we treated human/hamster hybrid cells containing an inactive human X chromosome with the DNA demethylating agent 5-azadeoxycytidine (5aCdr), and we then examined the high resolution methylation pattern of the HPRT promoter in single cell-derived lines. Reactivation of HPRT correlated with complete promoter demethylation. In contrast, the 61 5aCdr-treated clones that failed to reactivate HPRT exhibited sporadic promoter demethylation. However, three specific CpG sites remained methylated in all unreactivated clones, suggesting these sites may be critical for maintaining transcriptional silencing of the HPRT gene. Re-treatment of partially demethylated (and unreactivated) clones with a second round of 5aCdr did not increase the frequency of HPRT reactivation. This is consistent with mechanisms of methylation-mediated repression requiring methylation at specific critical sites and argues against models invoking overall levels or a threshold of promoter methylation. Treatment of cells with the histone deacetylase inhibitor, trichostatin A, failed to reactivate HPRT on the inactive X chromosome, even when the promoter was partially demethylated by 5aCdr treatment, suggesting that transcriptional repression by DNA methylation is unlikely to depend upon a trichostatin A-sensitive histone deacetylase.

Haptic force-feedback devices for the office computer: performance and musculoskeletal loading issues

Pointing devices, essential input tools for the graphical user interface (GUI) of desktop computers, require precise motor control and dexterity to use. Haptic force-feedback devices provide the human operator with tactile cues, adding the sense of touch to existing visual and auditory interfaces. However, the performance enhancements, comfort, and possible musculoskeletal loading of using a force-feedback device in an office environment are unknown. Hypothesizing that the time to perform a task and the self-reported pain and discomfort of the task improve with the addition of force feedback, 26 people ranging in age from 22 to 44 years performed a point-and-click task 540 times with and without an attractive force field surrounding the desired target. The point-and-click movements were approximately 25% faster with the addition of force feedback (paired t-tests, p < 0.001). Perceived user discomfort and pain, as measured through a questionnaire, were also smaller with the addition of force feedback (p < 0.001). However, this difference decreased as additional distracting force fields were added to the task environment, simulating a more realistic work situation. These results suggest that for a given task, use of a force-feedback device improves performance, and potentially reduces musculoskeletal loading during mouse use. Actual or potential applications of this research include human-computer interface design, specifically that of the pointing device extensively used for the graphical user interface.

Ultrasonic irradiation effect in the impregnation-reduction process of preparing Pt/Nafion NH(4)(+) sensor

A systematic study on the ultrasonic irradiation effect in the impregnation-reduction (I-R) process for preparing a Pt/Nafion electrode was carried out in a flow-injection system of ammonium ion detection. Both the impregnation and the reduction stages were affected by ultrasonic irradiation which increased the sensing currents of electrodes. Moreover, the effect of ultrasonic irradiation was found more significant in the reduction process than in the impregnation process. The relationship between sensing current and power of ultrasonic irradiation was also obtained. The specific active surface area of the Pt/Nafion electrodes were evaluated by the cyclic voltametric technique. Meanwhile, the surfaces of the electrodes were characterized by XRD and SEM.

BR22, a novel protein, interacts with thyroid transcription factor-1 and activates the human surfactant protein B promoter

Surfactant protein (SP)-B expression is restricted to type II pneumocytes and Clara cells in the lung. Previously, a promoter region of human SP-B gene from -64 to -118 has been identified as critical for the tissue-specific expression of this gene. Two cis-elements for thyroid transcription factor (TTF)-1 and hepatocyte nuclear factor (HNF)-3alpha binding were found within this area. Using an oligonucleotide fragment, we incorporated this region sequence into the promoter of a HIS3 reporter gene in yeast. With this modified yeast a human lung complementary DNA (cDNA) library was screened for DNA-binding proteins, other than TTF-1 and HNF-3alpha, that interacted with this promoter segment. A cDNA clone encoding a novel polypeptide, BR22, was identified that activated the reporter gene expression in yeast. This gene is expressed in many tissues and encodes a protein with bipartite nuclear localization signals. Studies using in vivo yeast two-hybrid analysis, in vitro protein-protein interactions, and coimmunoprecipitation analyses demonstrated that BR22 formed a protein complex with TTF-1. In vivo cotransfection studies further indicated that BR22 could act with TTF-1 to synergistically activate the SP-B promoter in mammalian cells. Our data suggest that BR22 is a TTF-1-associated protein. Through a protein-protein interaction with TTF-1, BR22 can form a complex and activate the human SP-B promoter in vivo.

Influence of design of the hemodialyzer inlet chamber on red blood cell damage during hemodialysis

Red blood cell damage occurring in the inlet chamber of a hollow fiber dialyzer was investigated by using a simplified model assembly. To vary the geometry of the inlet chamber, four parameters were used in this study, including the entrance angle, the chamber length, the convergence ratio, and the number of holes. The degree of red blood cell damage was represented by the hemolysis ratio. The results show that the hemolysis ratio was affected mostly by the chamber length and the convergence ratio, and less affected by the entrance angle and number of holes. The hemolysis ratio was the lowest when the chamber length was 2 mm and the entrance angle was 15 degrees. In addition, the hemolysis ratio decreased with the convergence ratio. Because the hemolysis ratio was only slightly affected by the number of holes and the flow channel length, the experimental results of this simplified assembly can be used to improve the design of an actual inlet chamber.

Filler particle leachability of experimental dental composites

We studied the effect of matrix selection, filler composition, and filler silanization on filler leachability after storage in distilled water or artificial saliva. We evaluated 2 matrix systems, 2 filler systems and 2 silane treatment procedures, combined into 8 different dental composite materials. A total of 128 batches were made, and 2 specimens per batch were prepared. Of these 2 specimens per batch, one was stored in distilled water and the other in artificial saliva, both at 37 degrees C. We transferred the specimens each 30th day during a 3-yr period to new vials containing either freshly distilled water or newly mixed artificial saliva and analyzed the solutions the specimens had been stored in regarding Si, Ba and Al concentrations. The analyses revealed that storage solution, filler composition, and total time in the storage solution had strong effects on leachability. The average monthly leakage of the three elements was linear with time and higher in the artificial saliva. The Ba-containing filler leached Si faster in artificial saliva than in distilled water, and roughly twice as much as the quartz filler. The storage effect approached an order of magnitude, while the filler effect was roughly a factor of two. Filler leaching was linear over time.

Hepatic disposition of neurotoxins and pesticides

The hepatic disposition of pesticides and neurotoxins may influence susceptibility to Parkinson's disease. Therefore we examined the behaviour of paraquat, dichlorodiphenyltrichloroethane (DDT), malathion and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in perfused rat liver using the multiple indicator-dilution technique. The values for the recovery of paraquat, DDT, malathion and MPTP were 1.05+/-0.12, 0.32+/-0.01, 0.11+/-0.02 and 0.02+/-0.01, respectively. The volumes of distribution were 0.28+/-0.13, 0.69+/-0.12, 3.30+/-0.58 and 5.10+/-6.00 ml/g, respectively. The permeability-surface area products suggest that transport of DDT and MPTP across cell membranes is by simple diffusion. However, there may be a specific influx mechanism for malathion and a specific efflux mechanism for paraquat. There is considerable variability in the hepatic disposition of putative neurotoxins such as MPTP and pesticides. Factors that influence the hepatic disposition of neurotoxins may alter susceptibility to neurotoxic diseases however the effects will be diverse.

A novel post-translational modification of yeast elongation factor 1A. Methylesterification at the C terminus

Protein methylation reactions can play important roles in cell physiology. After labeling intact Saccharomyces cerevisiae cells with S-adenosyl-l-[methyl-(3)H]methionine, we identified a major methylated 49-kDa polypeptide containing [(3)H]methyl groups in two distinct types of linkages. Peptide sequence analysis of the purified methylated protein revealed that it is eukaryotic elongation factor 1A (eEF1A, formerly EF-1alpha), the protein that forms a complex with GTP and aminoacyl-tRNAs for binding to the ribosomal A site during protein translation. Previous studies have shown that eEF1A is methylated on several internal lysine residues to give mono-, di-, and tri-N-epsilon-methyl-lysine derivatives. We confirm this finding but also detect methylation that is released as volatile methyl groups after base hydrolysis, characteristic of ester linkages. In cycloheximide-treated cells, methyl esterified eEF1A was detected largely in the ribosome and polysome fractions; little or no methylated protein was found in the soluble fraction. Because the base-labile, volatile [methyl-(3)H]radioactivity of eEF1A could be released by trypsin treatment but not by carboxypeptidase Y or chymotrypsin treatment, we suggest that the methyl ester is present on the alpha-carboxyl group of its C-terminal lysine residue. From the results of pulse-chase experiments using radiolabeled intact yeast cells, we find that the N-methylated lysine residues of eEF1A are stable over 4 h, whereas the eEF1A carboxyl methyl ester has a half-life of less than 10 min. The rapid turnover of the methyl ester suggests that the methylation/demethylation of eEF1A at the C-terminal carboxyl group may represent a novel mode of regulation of the activity of this protein in yeast.

Autoantigen Ro52 directly interacts with human IgG heavy chain in vivo in mammalian cells

Previously, when we used in vivo yeast two-hybrid and in vitro protein-protein interaction analyses, we demonstrated a direct interaction between autoantigen Ro52 and the human IgG heavy chain. This interaction occurred in the absence of antibody-antigen specific interaction. Here, by employing a novel strategy, we further demonstrated that Ro52 co-localized with IgG in transfected mammalian cells. The co-localization was specific to IgG1 but not IgG3. Co-immunoprecipitating IgG with Ro52 from transfected cell lysates suggested that protein complex containing Ro52 and IgG contributed to the in vivo co-localization. In addition, IgG from normal human serum was shown to bind to the surface of apoptotic keratinocytes and the binding could be competitively blocked by 50-fold excesses of IgG1, not IgG3. With a direct binding study, we also demonstrated that IgG1 could bind to the surface of apoptotic cells while IgG3 bound barely. This binding was not competed by Fcgamma fragments indicating a non-Fcgamma receptor mediated interaction. Finally, in a competition analysis the addition of GST-RFP could reduce the IgG binding to the cell surface. Thus, we suggested that the binding of IgG to the apoptotic keratinocytes might be mediated through the interactions with the surface exposed Ro52. The potential role of forming this protein complex on the apoptotic cells will be discussed.

Effect of MMA-g-UHMWPE grafted fiber on mechanical properties of acrylic bone cement

Ultrahigh molecular weight polyethylene (UHMWPE) fibers were treated with argon plasma for 5 min, followed by uv irradiation in methyl methacrylate (MMA)-chloroform solution for 5 h to obtain MMA-g-UHMWPE grafted fiber. The grafting content was estimated by the titration of esterification method. The grafting amount of 5280 nmol/g was the largest for the MMA concentration at 18.75 vol%. To improve the mechanical properties of acrylic bone cement, pure UHMWPE fiber and MMA-g-UHMWPE fiber were added to the surgical Simplex. P radiopaque bone cement. The mechanical properties including tensile strength, tensile modulus, compressive strength, bending strength, and bending stiffness were measured. Dynamic mechanical analysis was also performed. By comparing the effect of the pure UHMWPE fiber and MMA-g-UHMWPE grafted fiber on the mechanical properties of acrylic bone cement, it was found that the acrylic bone cement with MMA-g-UHMWPE grafted fiber had a more significant reinforcing effect than that with untreated UHMWPE fiber. This might be due to the improvement of the interfacial bonding between the grafted fibers and the acrylic bone cement matrix.

Characterization of acrylic bone cement using dynamic mechanical analysis

Dynamic mechanical analysis (DMA) was used to characterize the properties of acrylic bone cement with the addition of tricalcium phosphate (TCP), hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate (EGDMA). The glass transition temperature of acrylic bone cement is >100 degrees C; the cement has a flat modulus response near human body temperature. The height of the damping peak decreases and becomes broader with increasing TCP content. Thus, TCP is incompatibile with acrylic bone cement. When the frequency is changed from high to low, the damping peak shifts to low temperature. The shift in damping peak with frequency indicates that this relaxation is time-dependent. When acrylic bone cement contains TCP with HEMA and EGDMA, the incompatibility between acrylic bone cement and TCP can be ameliorated.

In vitro characterization of the occurrence of hemolysis during extracorporeal blood circulation using a mini hemodialyzer

A minimodule dialyzer was made of polyacrylonitrile (PAN) hollow fibers and tested in an in vitro circuit under varying flow rates and blood volumes. Hemolysis occurred in the open circuit in the inlet and outlet chambers. The module was measured to investigate the hemolysis effect during dialysis. The results show that hemolysis ratio (HR) increased with blood flow rate. When the blood speed was increased from 27 to 70 cm/sec, the damaged fraction of red blood cells increased from 0.8% to 1.5%. Shearing in the hollow fiber contributed approximately 13% of the overall HR. Approximately 55% of the overall HR occurred at the inlet and outlet chambers. With increasing blood volume, the contacting surface area per unit blood volume (S/V) and the frequency of pump squeezing of red cells were decreased; hence the damage to the red blood cells and thus reduction of HR. When S/V was 2 cm(-1), the damaged fraction of red cells was approximately 0.7%. In addition, the tubing and connectors of the circuit caused further damage to the red blood cells. By referring to the linear velocity and blood volume, we can predict the HR in an actual protocol from the results of this experiment. This should improve the quality of hemodialysis and benefit the patient.

Genetic and physical mapping of a type 1 diabetes susceptibility gene (IDDM12) to a 100-kb phagemid artificial chromosome clone containing D2S72-CTLA4-D2S105 on chromosome 2q33

Polymorphic markers within the CTLA4 gene on chromosome 2q33 have been shown to be associated with type 1 diabetes. Therefore, a gene responsible for the disease (IDDM12) most likely lies within a region of <1-2 cM of CTLA4. To define more precisely the IDDM12 interval, we genotyped a multiethnic (U.S. Caucasian, Mexican-American, French, Spanish, Korean, and Chinese) collection of 178 simplex and 350 multiplex families for 10 polymorphic markers within a genomic interval of approximately 300 kb, which contains the candidate genes CTLA4 and CD28. The order of these markers (D2S346, CD28, GGAA19E07, D2S307, D2S72, CTLA4, D2S105, and GATA52A04) was determined by sequence tagged site content mapping of bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC) clones. The transmission disequilibrium test (TDT) analyses of our data revealed significant association/linkage with three markers within CTLA4 and two immediate flanking markers (D2S72 and D2S105) on each side of CTLA4 but not with more distant markers including the candidate gene CD28. Tsp analyses revealed significant association only with the three polymorphic markers within the CTLA4 gene. The markers linked and associated with type 1 diabetes are contained within a phagemid artificial chromosome clone of 100 kb, suggesting that the IDDM12 locus is either CTLA4 or an unknown gene in very close proximity.

Fine-mapping of the type 1 diabetes locus (IDDM4) on chromosome 11q and evaluation of two candidate genes (FADD and GALN) by affected sibpair and linkage-disequilibrium analyses

Previous studies have identified a susceptibility region for insulin-dependent (type 1) diabetes mellitus on chromosome 11q13 (IDDM4). In this study, 15 polymorphic markers were analyzed for 382 affected sibpair (ASP) families with type 1 diabetes. Our analyses provided additional evidence for linkage for IDDM4 (a peak LOD score of 3.4 at D11S913). The markers with strong linkage evidence are located within an interval of approximately 6 cM between D11S4205 and GALN. We also identified polymorphisms in two candidate genes, Fas-associated death domain protein (FADD) and galanin (GALN). Analyses of the data by transmission/disequilibrium test (TDT) and extended TDT (ETDT) did not provide any evidence for association/linkage with these candidate genes. However, ETDT did reveal significant association/linkage with the marker D11S987 (P=0.0004) within the IDDM4 interval defined by ASP analyses, suggesting that IDDM4 may be in the close proximity of D11S987.

Establishing a cost estimation model for hypertension and its related diseases in Taiwan

Chronic diseases are responsible for significant economic losses related to direct costs of medical care, as well as indirect costs arising from lost productivity. To optimize the use of limited health care resources, there is a need to establish a comprehensive index to establish the priorities for funding of health programs for chronic diseases. In this study, we applied the population attributable risk proportion (PAR) model to estimate the economic burden imposed by hypertension and its related diseases in Taiwan in 1991. Data were collected from published statistical reports and research reports. The estimated total economic cost of hypertension and associated diseases was 9.0 to 11.9 billion New Taiwan dollars (NTD) in 1991 (1 US dollar was equivalent to 27 NTD in 1991). Direct costs were the largest component of total expenditure (5.4-7.1 billion NTD), followed by morbidity costs (3.2 billion NTD), and mortality costs (0.4-1.5 billion NTD). Categorized by disease type, hypertensive diseases accounted for the largest share of costs (6.8-7.7 billion NTD), followed by cerebrovascular diseases (1.0-1.9 billion NTD). Disorders of arteries, arterioles, and capillaries accounted for the smallest share (41 million to 1 billion NTD). The method used in this study provides a satisfactory estimation of the economic burden imposed by hypertension and related diseases, and can be applied to other risk factors or diseases to show their separate economic impacts. The precision of such estimates can be greatly improved if health authorities establish more complete databanks to collect data on national expenditure for all types of health care services. This would, in turn, provide policy makers with more accurate data on which to base allocation of funding for chronic disease health care programs.

Cost-effective design for dental randomized clinical trials with longitudinal observations

In general, randomized clinical trials (RCT) in dentistry involve longitudinal observations. In such studies, the total cost is a function of the number of study subjects and visits, the study duration, and the type and number of examinations at each visit. In this paper, we derived the minimum cost design for longitudinal RCTs with 2 treatment arms and multiple visits. We optimized the number of subjects, visits and repeated measurements under the constraints of the requirements for statistical significance, power and minimum total study cost. A SAS macro was written and made available on the World Wide Web, so interested clinical investigators can easily find optimal designs. The application of the program is illustrated using an example.

Combinations of HLA DR and DQ molecules determine the susceptibility to insulin-dependent diabetes mellitus in Koreans

The association of HLA-DRB1 and DQB1 genes with IDDM in Koreans was assessed using 115 IDDM patients and 140 nondiabetic controls. DQB1*0201 is the only DQB1 allele positively associated with IDDM while DQB*0602, *0601 and *0301 are negatively associated. Three DRB1 alleles (DRB1*0301, DRB1*0407 and DRB1*0901) are positively associated while four DR allele groups (DRB1*15, DRB1*12, DRB1*10 and DRB1*14) are negatively associated. However, Haplotype analyses indicated that DQB1*0302, DRB1*0405 and DRB1*0401 may confer susceptibility because the DRB1*0405-DQB*0302 and DRB1*0401-DQB1*0302 haplotypes are positively associated with the disease. The lack of association in Koreans with the DQB1*0302 allele, which appears predisposing in studies of non-Orientals, is due to its strong linkage disequilibrium (LD) with the protective DRB1*0403 and *0406 alleles, while the lack of association with DRB1*0405 is because of its strong LD with the protective DQB1*0401 allele. Nine DR/DQ genotypes confer significantly increased risk to IDDM. Seven of the nine genotypes (DR3/4s, DR1/4s, DR4s/13, DR4s/8, DR4s/7, DR9/13 and DR3/9) were also found to be at high risk to IDDM in other populations, while the two others (DR1/9 and DR9/9) are only found in Koreans. Surprisingly, DR4/4 homozygotes are not associated with high risk to IDDM in Koreans. This observation can be explained by the high frequency of protective DR4 subtypes and the protective DQ alleles (0301 and 0401) associated with the susceptible DR4 alleles. Our analyses indicate that the counterbalancing act between susceptible DRB1 and protective DQB1, and vice versa, that has already been observed in Chinese and Japanese, is the major factor responsible for the low incidence of diabetes in Koreans.