Rates of implantable cardioverter defibrillator implantation and outcomes in octogenarians or older compared to non-octogenarians in a statewide cohort from 2009 to 2018

Background

Octogenarians are underrepresented or excluded in major implantable cardioverter defibrillator (ICD) trials. The deployment of ICDs and their real-world outcomes in octogenarians is unclear.

Purpose

To investigate the prevalence and outcomes of ICD implantation in octogenarian or older vs non-octogenarian.

Methods

We extracted details of all ICD implanted statewide from 2009–2018 including patient's characteristics, in-hospital complications and mortality using the Centre-for-Health-Record-Linkage administrative datasets. Implantation rates were adjusted for the population size by sex, age-groups in decade and calendar-year. Analysis was stratified by age <80 vs ≥80yo.

Results

There were 9304 admissions (12.1% ≥80yo) for de novo ICD implantation (mean±SD implantation: 1163±122 cases per-annum). The mean age for ≥80 vs <80yo groups was 83.5±2.9yo vs 66.2±12.1yo respectively (overall cohort mean age 66.1±13.1yo). Total ICD implantations increased by 8.4±12.4% vs 1.8±8.4% per-annum for ≥80 vs <80yo groups. The mean implantation rates were 52.7±10.8 vs 22.0±2.8 per-100,000-persons in ≥80yo compared to <80yo, respectively, with rates increasing at 7.7±18.3% per-100,000-persons-per-annum in ≥80yo. In contrast, implantation rates declined slightly by 0.2±12.4% per-100,000-persons-per-annum in <80yo groups. There was a non-significant trend towards more in-hospital non-fatal complications in ≥80yo compared to <80yo (10.8% vs 9.0% respectively, p=0.054), with no difference in in-hospital mortality (0.6% vs 0.4% respectively, p=0.32). The 1-year mortality was 10.7% in ≥80yo compared to 4.7% in <80yo (p<0.001), and 2-year mortality was 20.2% vs 8.8% respectively (p<0.001). The 1-yr and 2-yr mortality hazard ratio for ≥80yo was 2.0 (95% confidence interval [CI] 1.6–2.5, p<0.001) and 2.2 (95% CI 1.8–2.5, p<0.001) respectively after adjusting for sex, year of implantation, referral source, indications for ICD, and comorbidities. Overall, the annual rates of total in-hospital non-fatal complications and mortality did not alter significantly during the study period.

Conclusion

Despite limited clinical trials data on efficacy of ICD use in octogenarians or older, implantation rate was more than double that of <80yo age-groups, with the implantation rate observed to be increasing in ≥80yo. There was no significant difference in in-hospital mortality between the two age-groups, however the 1-year and 2-year mortality rates were significantly higher in the ≥80yo.

Funding Acknowledgement

Type of funding sources: None.

Population-based high-throughput toxicity screen of human iPSC-derived cardiomyocytes and neurons

In this study, we establish a population-based human induced pluripotent stem cell (hiPSC) drug screening platform for toxicity assessment. After recruiting 1,000 healthy donors and screening for high-frequency human leukocyte antigen (HLA) haplotypes, we identify 13 HLA-homozygous "super donors" to represent the population. These "super donors" are also expected to represent at least 477,611,135 of the global population. By differentiating these representative hiPSCs into cardiomyocytes and neurons we show their utility in a high-throughput toxicity screen. To validate hit compounds, we demonstrate dose-dependent toxicity of the hit compounds and assess functional modulation. We also show reproducible in vivo drug toxicity results using mouse models with select hit compounds. This study shows the feasibility of using a population-based hiPSC drug screening platform to assess cytotoxicity, which can be used as an innovative tool to study inter-population differences in drug toxicity and adverse drug reactions in drug discovery applications.

[A case of atypical iris corneal endothelial syndrome]

Iridocorneal endothelial syndrome is a rare ophthalmic disease, most of which are unilateral and common in women. The rate of misdiagnosis and missed diagnosis is relatively high due to its various clinical manifestations. In this case, the patient presented uncontrollable high intraocular pressure, corneal edema leading to difficult observation of corneal endothelium morphology, and accompanied by a small amount of iris neovascularization. No clearly diagnosis was made before glaucoma surgery. Further examination was performed after corneal clearance, and the final diagnosis was iris corneal endothelial syndrome (Chandler syndrome).

LGR6 promotes glioblastoma malignancy and chemoresistance by activating the Akt signaling pathway

Chemoresistance is the primary cause of the poor outcome of glioblastoma multiforme (GBM) therapy. Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) is involved in the growth and proliferation of several types of cancer, including gastric cancer and ovarian cancer. Therefore, the aim of the present study was to investigate the role of LGR6 in GBM malignancy and chemoresistance. Cell counting kit-8 and Matrigel®-Transwell assays were conducted to assess GBM cell viability and invasion. The effect of LGR6 on cell cycle progression and activation of Akt signaling was analyzed by performing propidium iodide staining and western blotting, respectively. The results demonstrated that LGR6, a microRNA-1236-3p target candidate, promoted GBM cell viability and invasion, and mediated temozolomide sensitivity in SHG-44 and U251 GBM cells. In addition, LGR6 triggered the activation of the Akt signaling pathway during GBM progression. Collectively, the results of the present study suggested that LGR6 promoted GBM malignancy and chemoresistance, at least in part, by activating the Akt signaling pathway. The results may aid with the identification of a novel therapeutic target and strategy for GBM.

miR-375 inhibits the proliferation and invasion of glioblastoma by regulating Wnt5a

The aberrant expression of microRNA-375 (miR-375) has been proved to be associated with carcinogenesis. However, the role of miR-375 in glioblastoma (GBM) remains unknown. The aim of this study was to investigate biological functions and its molecular mechanisms of miR-375 in GBM cells. In this study, real-time PCR results showed that the level of miR-375 expression in GBM tissues and GBM cell lines (U87 and U251) was decreased. Using MTT assay, Transwell migration and invasion assay, we demonstrated that miR-375 overexpression significantly suppress cell proliferation, cell migration and cell invasion capacity in U87 and U251 cells. However, downregulation of miR-375 had reverse effects on cell proliferation, migration and invasion. Targeting association analysis, dual luciferase assay, RT-PCR and western blot analysis results confirmed that miR-375 could target the 3'UTR of Wnt5a mRNA and regulated its protein expression. Further studies also find overexpression of Wnt5a could significantly reverse miR-375-mediated proliferation, migration and invasion on U87 and U251 cells. Therefore, we concluded that miR-375 inhibited the proliferation and invasion of GBM by regulating Wnt5a and might be a possible therapeutic agent for GBM.

Multiple variants in 5q31.1 are associated with systemic lupus erythematosus susceptibility and subphenotypes in the Han Chinese population

BACKGROUND

A previous study provided evidence for a genetic association between PPP2CA on 5q31.1 and systemic lupus erythematosus (SLE) across multi-ancestral cohorts, but failed to find significant evidence for an association in the Han Chinese population.

OBJECTIVES

To explore the association between this locus and SLE using data from our previously published genome-wide association study (GWAS).

METHODS

Single-nucleotide polymorphisms (SNPs) rs7726414 and rs244689 (near TCF7 and PPP2CA in 5q31.1) were selected as candidate independent associations from a large-scale study in a Han Chinese population consisting of 1047 cases and 1205 controls. Subsequently, 3509 cases and 8246 controls were genotyped in two further replication studies. We then investigated the SNPs' associations with SLE subphenotypes and gene expression in peripheral blood mononuclear cells.

RESULTS

Highly significant associations with SLE in the Han Chinese population were detected for SNPs rs7726414 and rs244689 by combining the genotype data from our previous GWAS and two independent replication cohorts. Further conditional analyses indicated that these two SNPs contribute to disease susceptibility independently. A significant association with SLE, age at diagnosis < 20 years, was found for rs7726414 (P = 0·001). The expression levels of TCF7 and PPP2CA messenger RNA in patients with SLE were significantly decreased compared with those in healthy controls.

CONCLUSIONS

This study found evidence for multiple associations with SLE in 5q31.1 at genome-wide levels of significance for the first time in a Han Chinese population, in a combined genotype dataset. These findings suggest that variants in the 5q31.1 locus not only provide novel insights into the genetic architecture of SLE, but also contribute to the complex subphenotypes of SLE.

Linkage analysis of SNPs in IGFBP-6 and its relation with the body sizes of pig

Insulin-like growth factor binding protein-6 (IGFBP-6) is a member of the IGFBP family, which is known to be a key factor in regulating the effect of insulin-like growth factor-2 (IGF-2) on the animal growth and development. Gene sequences of 3'-untranslated regions (UTR) and exon 4 of IGFBP-6 may influence the expression and proteolysis of IGFBP-6. In this study, 551 bp of the IGFBP-6 (including 257 bp of intron 3, exon 4, and 170 bp of 3' UTR) were sequenced and compared in the Bama and Tibetan mini-pigs, the Landrace and Large White pigs, and the Northeast wild boars. Six single nucleotide polymorphisms (SNPs) were detected in the IGFBP-6, in which T593C, T636C, and T745C were in intron 3, A67G was in exon 4, and G37A was in 3' UTR. T636C, T745C, and A67G were in linkage and formed four kinds of haplotypes, with CCT being the dominant haplotype in the mini-pigs; however, the haplotype block was not formed in the Landrace pigs and Large White pigs or the Northeast wild boars. Based on the above results, we concluded that the SNPs and haplotype of the IGFBP-6 may be related to the mini-size formation of the pig.

An RNAi-based screen reveals PLK1, CDK1 and NDC80 as potential therapeutic targets in malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is an aggressive tumour originating in the thoracic mesothelium. Prognosis remains poor with 9- to 12-month median survival, and new targets for treatments are desperately needed.

METHODS

Utilising an RNA interference (RNAi)-based screen of 40 genes overexpressed in tumours, including genes involved in the control of cell cycle, DNA replication and repair, we investigated potential therapeutic targets for MPM. Following in vitro characterisation of the effects of target silencing on MPM cells, candidates were assessed in tumour samples from 154 patients.

RESULTS

Gene knockdown in MPM cell lines identified growth inhibition following knockdown of NDC80, CDK1 and PLK1. Target knockdown induced cell-cycle arrest and increased apoptosis. Using small-molecule inhibitors specific for these three proteins also led to growth inhibition of MPM cell lines, and Roscovitine (inhibitor of CDK1) sensitised cells to cisplatin. Protein expression was also measured in tumour samples, with markedly variable levels of CDK1 and PLK1 noted. PLK1 expression in over 10% of cells correlated significantly with a poor prognosis.

CONCLUSION

These results suggest that RNAi-based screening has utility in identifying new targets for MPM, and that inhibition of NDC80, CDK1 and PLK1 may hold promise for treatment of this disease.

Sol/gel transition of chitosan solutions

This work studies the occurrence of sol/gel transition and the gel rheology for chitosan solution under various conditions. Experiments were conducted in an oscillatory shear apparatus with small amplitude, using a Rheometrics SR-5 rheometer, with Couette and parallel plate geometries. The experimental results demonstrate that the sol/gel transition concentration and the elastic modulus (G') for CS gel decrease as the pH value and the molecular weight (Mw) increase. However, the sol/gel transition concentration and G' became independent of Mw when Mw exceeded a threshold. The higher ionization constant, Kp, is responsible for the higher sol/gel transition concentration in a formic acid solution than in an acetic acid solution with equivalent molar concentration. The elastic modulus G' of a CS gel increases with temperature, which relationship differs from that for many polysaccharides, and can be understood through classical rubber elastic theory. Finally, a gel whose concentration was barely above the sol/gel point exhibited aging, and its G' and G" declined rather than increase with time, accompanied by a reversal from the sol/gel state back to the sol state. This is an uncommon aging behavior for a polysaccharide and a detailed explanation is provided.

3D FEA of high-performance polyethylene fiber reinforced maxillary dentures

OBJECTIVE

This project studies the effect of high-performance polyethylene (HPPE) fibers on stress distributions in a maxillary denture and the influence of fiber position on improving denture performance.

METHODS

A denture was scanned with a 3D Advanced Topometric Sensor digitizing system. The measuring system converted the images into a 3D digital model. A 3D reverse engineering technology then produced a numerical model which was then refined with Rapidform software. The underlying mucosa and bone were constructed using a freeform system integrated with a PHANTOM haptic device. A fiber lamella reinforcement was incorporated into the denture at different positions (fitting side, mid-palatal plane, polished side) with SolidWorks software. Boundary conditions were constrained at the top of the basal bone while bite force of 230 N was applied to the posterior teeth on both sides. The denture models were analyzed with ABAQUS software.

RESULTS

Stress concentrations were found at the incisal notch and at the anterior and posterior palatal surfaces of the unreinforced denture. The incorporated reinforcement effectively reduced the stress concentrations at these surfaces. Placement of the fibers at polished side was the best position in reducing stress concentrations.

SIGNIFICANCE

3D FEM usefully provides a non-laboratory means to reveal the weak areas in the maxillary complete denture, and exhibit the effectiveness of HPPE reinforcement together with fiber positions on enhancement of denture strength.

Fibulin 1 is downregulated through promoter hypermethylation in gastric cancer

Tumour suppressor genes (TSGs) were frequently inactivated through promoter hypermethylation in gastric carcinoma as well as pre-malignant gastric lesions, suggesting that promoter hypermethylation can be used as a marker to define novel TSGs and also biomarkers for early detection of gastric cancer. In an effort to search for such genes aberrantly methylated in gastric cancer development, fibulin 1 (FBLN1) was found as a candidate TSG epigenetically downregulated in gastric cancer. FBLN1 expression was downregulated in all of gastric cancer cell lines used (100%, 7 out of 7) and the primary gastric carcinoma tissues (84%, 86 out of 102) and significantly restored after pharmacological demethylation. Hypermethylation of the FBLN1 promoter was frequently (71%, 5 out of 7) detected in gastric cancer cell lines and primary gastric carcinoma tissues. Ectopic expression of FBLN1 led to the growth inhibition of gastric cancer cells through the induction of apoptosis. In summary, FBLN1 was identified as a novel candidate TSG epigenetically downregulated in gastric cancer.

Frequent epigenetic inactivation of secreted frizzled-related protein 2 (SFRP2) by promoter methylation in human gastric cancer

The role of secreted frizzled-related protein (SFRP) genes in gastric cancer remains largely unknown. We determined the frequency and functional significance of SFRPs hypermethylation in human gastric cancer. The expression and methylation status of four SFRP members (SFRP1, 2, 4, and 5) in primary gastric cancer samples was screened. The biological effects of SFRP were analysed by flow cytometry, cell viability assay and in vivo tumour growth in nude mice. Among the four SFRPs, only SFRP2 was significantly downregulated in gastric cancer as compared to adjacent non-cancer samples (P<0.01). Promoter hypermethylation of SFRP2 was detected in 73.3% primary gastric cancer tissues, 37.5% of samples showing intestinal metaplasia and 20% adjacent normal gastric tissues. Bisulphite DNA sequencing confirmed the densely methylated SFRP2 promoter region. Demethylation treatment restored the expression of SFRP2 in gastric cancer cell lines. Forced expression of SFRP2 induced cell apoptosis, inhibited proliferation of gastric cancer cells and suppressed tumour growth in vivo. Moreover, methylated SFRP2 was detected in 66.7% of serum samples from cancer patients but not in normal controls. In conclusion, epigenetic inactivation of SFRP2 is a common and early event contributing to gastric carcinogenesis and may be a potential biomarker for gastric cancer.

Bisphosphonates induce apoptosis of stromal tumor cells in giant cell tumor of bone

Giant cell tumour of bone (GCT) is an aggressive primary neoplasm that results in the production of osteolytic lesions. Stromal cells, which form the main neoplastic component of this tumor, regulate the formation of osleoclast-like giant cells that are ultimately responsible for bone destruction. Bisphosphonates prevent bone resorption by inhibiting osteoclast activity and promoting osteoclast apoptosis, and they have been known to induce apoptosis of primary neoplastic cells such as those in breast and prostate cancers. We hypothesized that in bisphosphonates may induce apoptosis not only in osteoclast-like giant cells but also in neoplastic stromal cells of GCT both in vitro and in vivo. Twelve patients with GCT were treated with weekly injections of pamidronate for a period of 6 weeks prior to surgery. GCT specimens were collected at the time of biopsy and during definitive surgery. TUNEL assay was used to evaluate apoptotic DNA fragmentation in cells. In addition, twelve GCT primary cultures from these patients were treated with zoledronate, pamidronate, or alendronate for 48 hours at different doses (3, 30, or 150 microM) and subjected to apoptosis assay by flow cytometry following fluorescent Annexin-V labeling. The results showed that pamidronate significantly induced apoptosis in both osteoclast-like giant cells and stromal tumor cells, in vivo. All three bisphosphonates caused substantial apoptosis of stromal tumor cells in cultures. Zoledronate was the most potent reagent, resulting in an average cell death of 27.41% at 150 microM, followed by pamidronate (22.23%) and alendronate (15.3%). Our observations suggest that these drugs may be considered as potential adjuvants in the treatment of GCT.

Alendronate regulates cell invasion and MMP-2 secretion in human osteosarcoma cell lines

BACKGROUND

Osteosarcoma is the most common malignant bone tumor of childhood. Significant proportions of these patients eventually develop pulmonary metastases and succumb to their disease even after conventional multi-agent chemotherapy and surgical excision. Matrix metalloproteinase (MMP)-2 induced degradation of blood vessel basement membranes is an important pre-requisite for tumor invasion and metastasis. Bisphosphonates (BPs) have been known to inhibit tumor growth and metastasis in some tumors such as breast cancer, renal cell carcinoma, and prostate cancer, and may do so through inhibition of MMP secretion. We, therefore, tested the effect of BPs on tumor cell invasion, MMP-2 secretion, and apoptosis of osteosarcoma cell lines.

PROCEDURE

Two osteosarcoma cell lines (SaOS-2, U(2)OS) were treated with alendronate (50, 100, and 150 microM) for 24 and 48 hr. Matrigel invasion assay was used to investigate the invasive potential of osteosarcoma cell lines before and after alendronate treatment. Real-time quantitative RT-PCR was used to determine the mRNA level of MMP-2 with and without alendronate treatment. Enzyme-linked immunosorbent assay (ELISA) was used to quantify the cytokine level of MMP-2 secreted in the condition medium. BP-induced cell apoptosis was evaluated by fluorescent flow cytometric analysis.

RESULTS AND CONCLUSIONS

The results showed that alendronate inhibited cell invasion of both osteosarcoma cell lines in a dose-dependent manner. Alendronate reduced the mRNA level and cellular level of MMP-2 in both cell lines in a time and dose-dependent manner. Alendronate also induced significant apoptosis in both cell lines. Our finding suggests that alendronate downregulates MMP-2 secretion and induces apoptosis in osteosarcoma cells, which may both contribute to the reduction of invasive potential of the tumor cells.

Expression of preosteoblast markers and Cbfa-1 and Osterix gene transcripts in stromal tumour cells of giant cell tumour of bone

In giant cell tumour of bone (GCT), mononuclear stromal cells, which represent the neoplastic component of this lesion, regulate the formation of multinucleated osteoclast-like giant cells which are the characteristic hallmark of this tumour. However, the origin of stromal tumour cells has not yet been clearly defined. In this study, we evaluated several osteoblast markers including collagen type I, bone sialoprotein (BSP), osteonectin and osteocalcin in GCT using immunohistochemical techniques. Amongst the 13 GCT specimens and 7 GCT stromal cell (GCTSC) cultures studied, majority of the GCTSC synthesized type I collagen, BSP and osteonectin proteins but did not produce the differentiated osteoblast marker, osteocalcin. We further examined the regulation of several important osteogenic genes such as Cbfa-1, osterix and osteocalcin, and regulation of ALP activity in GCTSC in culture by bone morphogenetic protein 2 (BMP-2). Real-time PCR analysis indicated that Cbfa-1, osterix and osteocalcin mRNA were present in primary cultures of GCTSC. The addition of BMP-2 upregulated Cbfa-1 and osterix gene expression within 12 h and the enhancement was still observed at 24 h. ALP activity was minimal in untreated GCTSC in cultures. The number of ALP-positive GCTSC was significantly increased following treatment with BMP-2 or combinations with beta-glycerophosphate and ascorbic acid. In contrast, BMP enhancement of osterix mRNA level and ALP activity was also seen in SaOS2 osteoblast-like cells, but not in the primary culture of normal human skin fibroblasts. In summary, our data suggest that GCT stromal tumour cells may have an osteoblastic lineage and retain the ability to differentiate into osteoblasts.

The effect of hyaluronan on osteoblast proliferation and differentiation in rat calvarial-derived cell cultures

Hyaluronan (or hyaluronic acid, HA) is an essential component of extracellular matrices. It interacts with other macromolecules and plays a predominant role in tissue morphogenesis, cell migration, differentiation, and adhesion. The cell signaling functions of HA are mediated through the CD-44 receptor and are dependent upon the molecular weight of the polymer. We hypothesized that an HA of appropriate molecular weight alone in optimal concentration may induce osteoblast differentiation and bone formation. Enzyme-digested calvarial-derived mesenchymal cells from 2-day-old newborn rats were cultured with the addition of HA of three different molecular weights (2300, 900, and 60 kDa). We added, 0.5, 1.0, and 2.0 mg/mL HA for each molecular weight to the medium at the first plating of cells. After 7 to 20 days in culture, cell proliferation and differentiation were evaluated by measuring thymidine incorporation, alkaline phosphatase activity, and osteocalcin gene expression. The effects of HA on bone formation were examined by using Alizarin red staining for mineralization. The results showed that low molecular weight HA (60 kDa) significantly stimulated cell growth, increased osteocalcin mRNA expression in a dose-dependent manner, but showed no apparent effects on alkaline phosphatase activity and bone mineralization. On the other hand, high-weight HA (900 and 2,300 kDa) significantly increased all the parameters examined, particularly alkaline phosphatase activity, in a dose-dependent manner and stimulated cell mineralization to 126% and 119% of the controls, respectively, in the 1.0 mg/mL dose. Our findings suggest that HA has a molecular weight-specific and dose-specific mode of action that may enhance the osteogenic and osteoinductive properties of bone graft materials and substitutes due to its stimulatory effects on osteoblasts.

Expression of VEGF and MMP-9 in giant cell tumor of bone and other osteolytic lesions

This study aims to investigate the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in giant cell tumor of bone (GCT) and other osteolytic lesions in bone. By using semi-quantitative RT-PCR, we showed that three major isoforms of VEGF (121, 165 and 189) were expressed in GCTs, with isoform 121 being the most abundant. The expression levels of VEGF and MMP-9 mRNA were significantly higher in advanced GCTs (stage II/III) than in stage I GCTs. We further elucidated the cellular localization of VEGF and MMP-9 gene transcripts in GCT and other osteolytic lesions using an in situ hybridization assay. The results showed that stromal tumor cells and osteoclast-like giant cells of GCT, fibrous stromal cells in anuerysmal bone cysts and fibrous dysplasia, and Langerhans-type giant cells as well as histocytes in eosinophillic granuloma, were all strongly positive for VEGF and MMP-9 mRNA expression. In a prospective study, we performed VEGF and MMP-9 immuno-staining on paraffin sections of pathological tissues harvested from 48 patients (14 GCT, 10 anuerysmal bone cysts, 10 eosinophillic granuloma, 4 fibrous dysplasia, 2 simple bone cyst, 2 osteomyelitis and 6 patients with fractured femoral head as control). The results showed that the differences in VEGF and MMP-9 expression between Stage I and other advanced Stages (II, III and recurrent) were highly significant (p<0.001), with advanced stages showing a higher mean expression. The difference between recurrent and Stage II and III lesions, was also statistically significant (p=0.03 for VEGF, and p=0.01 for MMP-9 expression), with recurrent lesions showing a higher mean expression of both VEGF and MMP-9. In conclusion, VEGF and MMP-9 expression in osteolytic lesions of bone co-relates well with the extent of bone destruction and local recurrence. Their expression may therefore provide some prognostic indication of the possible aggressive behavior of the underlying pathology.

Receptor activator of NF-kappaB ligand (RANKL) is expressed in chondroblastoma: possible involvement in osteoclastic giant cell recruitment

AIMS

Chondroblastoma is a rare, locally aggressive bone tumour that causes osteolytic destruction at the epiphyseal end of the affected bone. It is possible that tumour cells may stimulate osteoclastogenesis and osteolytic destruction through the production of receptor activator of NF-kappaB ligand (RANKL), which is a key molecule essential for regulating osteoclast formation and activity. Therefore, the expression of RANKL at both the mRNA and the protein level was investigated in chondroblastoma tumour tissue obtained from patients.

METHODS

The expression of RANKL gene transcripts was analysed by the reverse transcription-polymerase chain reaction (RT-PCR), and the cellular localisation of RANKL mRNA and protein was demonstrated by means of in situ hybridisation and immunohistochemistry.

RESULTS

RT-PCR analysis indicated that RANKL mRNA was present in all chondroblastoma specimens and normal cancellous bone samples, but not in normal articular cartilage and chondrosarcoma tissues. In contrast, gene transcripts of osteoprotegerin (OPG), the decoy receptor of RANKL, were detected in all types of tissues. The chondroid origin of neoplastic mononuclear cells in chondroblastoma was confirmed by positive S-100 immunohistochemical staining. Both RANKL mRNA and protein were exclusively expressed in these neoplastic mononuclear cells.

CONCLUSIONS

These findings suggest that RANKL may be involved in the tumour cell induced recruitment of osteoclast-like cells and consequent osteolytic bone destruction in chondroblastoma.

Events in the mould during heat processing of poly(methyl methacrylate)

Recordings of temperature and pressure in the mould have raised questions concerning the flow of poly(methylmethacrylate) during heat processing. Three simple experiments investigated flow of polymerised and partly polymerised poly(methylmethacrylate). Flow was not observed at normal processing temperatures. These results, combined with the results of previous work, suggest that as the mould heats up, thermal expansion of the dough exceeds polymerisation contraction, causing increase in pressure rather than flow. Maximum pressure occurs at maximum temperature. Thereafter, thermal expansion is reduced, polymerisation contraction increases and pressure in the mould drops. When the lowest pressure is reached the poly(methylmethacrylate) is polymerised.

Determination of dextromethorphan and its metabolite dextrorphan in human urine by capillary gas chromatography without derivatization

A sensitive, simple and accurate method was developed for determination of dextromethorphan (DM) and dextrorphan (DT) in human urine by capillary gas chromatography without derivatization. After an oral dose of 30 mg DM, urine samples were collected and extracted, then analyzed on 0.22 mmx17 m HP-1 capillary column. DM and its metabolite DT were analyzed simultaneously with good separation. Docosane was used as the internal standard (I.S.). The detector used was flame ionization detector (FID). There was a linear relationship between peak area ratios of analytes to I.S. and concentration of analytes over the concentration range 0.37-7.38 micromol/l for DM and 0.39-77.8 micromol/l for DT. The recovery was 88.1 approximately 103.9% for DM and 86.7 approximately 96.8% for DT. The within-day and between-day coefficients of variation were less than 7.4 and 7.3% (RSD) for the assay of DM and DT in urine, respectively. The limits of detection (LOD) were 0.30 micromol/l for DM and 0.16 micromol/l for DT. The limits of quantitation (LOQ) were 0.37 micromol/l (RSD<6%) for DM and 0.39 micromol/l (RSD<7%) for DT. The method has been applied to determine the oxidative phenotypes of cytochrome P450 2D6 (CYP2D6) in a Chinese population with metabolic ratio of DM in human urine.

Pressure and temperature changes in heat-cured acrylic resin during processing

OBJECTIVES

The aims of this study were to measure the pressure and temperature changes of acrylic resin during processing, to record the highest temperature reached when fast cured in boiling water and to determine the elevated boiling point of monomer under high pressure.

METHODS

A subminiature pressure transducer (temperature compensated to 94 degrees C) and a thermocouple were placed on the palate of a standardized maxillary complete denture base. A heat-cured resin (Trevalon C) was polymerized by a long heating cycle (72 degrees C for 6.5 h and 92 degrees C for 1.5 h). Recordings of pressure and temperature (n=6) were made at initial clamping of denture flasks and throughout the processing cycles of resin. The temperature of the resin was also monitored during a fast cycle, which was accomplished by placing the flask directly into boiling water for 40 min.

RESULTS

The pressure of acrylic dough inside the clamped flask was initially 11.5 atm (SD=3.2) and reached a peak of 22.0 atm (SD=3.5) during the long heating cycle. The elevated boiling point of monomer at increased pressure was calculated to be about 193 degrees C (at 11.5 atm) and 228 degrees C (at 22.0 atm). These elevated boiling points are higher than the maximum temperature 131 degrees C (SD=6.6) reached during the fast curing cycle. No porosity was observed even in the denture bases heat-cured by the fast cycle.

SIGNIFICANCE

The highest temperature reached by heating of resin during processing is well below the elevated boiling point of monomer. Monomer therefore does not boil in clamped denture flasks under sufficient pressure. Thus adequate clamp pressure prevents gaseous porosity irrespective of curing cycle used.

Measurement issues in screening outstanding teachers

Measurement issues that arise in a two-stage teacher evaluation for an outstanding faculty award are addressed. A teacher evaluation inventory with ten Likert-type items was developed. Thirty college teachers were rated by 293 students on the new inventory. The facet Rasch technique was applied to analyze the test data, and the items fit the Rasch models fairly well. The separation reliability for the teachers is.98, indicating that the items together with these students can differentiate the teachers extremely well. A cut score was set to.80 logits so that only those teachers with efficacy estimates above that level are eligible to apply for the award. A short version containing only half of the items was also developed.

Vitrification of mouse oocytes using closed pulled straws (CPS) achieves a high survival and preserves good patterns of meiotic spindles, compared with conventional straws, open pulled straws (OPS) and grids

BACKGROUND

We modified the loading of pulled straws into a new closed system, called closed pulled straws (CPS) for holding oocytes for vitrification. The morphological survival, dynamics of meiotic spindles, and fertilization in vitro of vitrified oocytes using CPS were compared with conventional straws, open pulled straws (OPS), and grids.

METHODS

Surviving oocytes were stained for spindles and chromosomes after 1, 2 and 3 h incubations, and compared with controls. The capacity of fertilization and embryonic cleavage were examined in vitro.

RESULTS

The survival rates of the CPS (79%) and straw (77%) groups were significantly higher (P < 0.05) than the OPS (63%) and grid (39%) groups. At a 1h incubation, vitrified oocytes of four groups had significantly fewer normal spindles than controls (P < 0.05). The straw group was inferior to the others in spindle morphology (P < 0.05). After a 3 h incubation, recovery of vitrified oocytes with normal spindles was significantly improved in all groups (P < 0.05). The percentages of fertilization and blastocyst formation of vitrified oocytes after a 1 h incubation was significantly lower than controls (P < 0.05), but they were improved after 2 or 3 h incubations (P < 0.05).

CONCLUSIONS

Oocytes vitrified using CPS, OPS or grids could lessen spindle injuries and expedite recuperation. The survival using OPS or grids is lower. Sufficient culture time for recovery of meiotic spindle would be imperative for fertilization events of vitrified oocytes. CPS has the advantages of achieving a high survival and preserving good spindles.

Risk factors of catheter-related infections in total parenteral nutrition catheterization

BACKGROUND

The use of central venous catheter for administration of total parenteral nutrition (TPN) is a risk factor of catheter-related infections (CRIs) that are associated with increased morbidity and mortality, prolonged hospitalization, and increased medical costs. The purpose of this study is to evaluate the risk factors of CRIs in patients with administration of TPN.

METHODS

A total of 1134 patients receiving TPN between January, 1996 and December, 1998 were studied. The category of infection included definite catheter-related bloodstream infection (CR-BSI), probable CR-BSI, and insertion site infection. Statistical analysis of risk factors was performed.

RESULTS

A total of 131 episodes of CRI occurred, representing an infection rate of 11.46%. Ninety-three episodes (8.1%) had probable CR-BSI, 13 episodes (1.1%) had definite CR-BSI, and 25 episodes (2.2%) had insertion site infection. Duration of TPN infusion and frequency of catheter insertion showed statistically significant difference by logistic regression multivariate analysis. The isolated organisms were in sequence of coagulase-negative Staphylococci (19.4%), Staphylococcus aureus (17.2%) and Candida albicans (14.4%).

CONCLUSIONS

Risk factors influencing the occurrence of CRI in TPN administration were multifactorial; however, duration of TPN infusion and frequency of catheter insertion were the main factors in our study.

Fabrication of complete denture bases reinforced with polyethylene woven fabric

Incorporation of 5 layers of woven, high-modulus polyethylene fiber into acrylic resin denture bases produces substantial improvements in mechanical properties and dimensional changes. A modified split-pack technique has been developed using conventional dental-laboratory compression molding to accommodate multiple layers of woven fabric in complete denture bases. A recess formed in the resin by a spacer allows the reinforcement to be embedded in the denture base without exposing the fibers. Embedded fibers do not compromise the esthetics of complete dentures.

Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakhstan: sources of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposures in an agricultural region of southern Kazakhstan

High levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; up to 208 pg/g fat) were measured in samples of breast milk collected in 1997 from 64 donors [41 first-time mothers (primiparae)] living on state farms in southern Kazakhstan. TCDD was the major contributor (70%) to the toxic equivalents, matching the congener patterns found in breast milk and serum samples collected in 1994 and 1996 from donors in nearby villages. The highest TCDD levels were found in state farms adjacent to a reservoir (zone A), which receives agricultural runoff from cotton fields. TCDD levels in zone A were significantly higher than levels in a region more distant (zone B; > 10 miles) from the reservoir (zone A: mean 53 pg/g, n = 17; zone B: mean 21 pg/g, n = 24; p = 0.0017). Levels of TCDD in breast milk and animal-derived foodstuffs were 10 times U.S. levels. Body burden and dietary data suggest that exposures to TCDD are chronic, environmental, and long term and may be related to the use of chemicals in cotton agriculture. The data suggest that the most likely source is the use of cotton defoliants contaminated with TCDD, and the most likely pathway for human exposure is via the consumption of contaminated foodstuffs.

Denture base reinforcement using woven polyethylene fiber

Reinforcement of acrylic denture base resin with high-performance polyethylene fiber in woven form produced a substantial improvement of stiffness and impact strength, as well as reducing the sensitivity of the material to notches that mimic anatomic features. The mechanical properties of the new systems were not affected by water immersion. Reinforced complete maxillary and mandibular dentures having good appearance and satisfactory fiber/resin integration were achieved using conventional laboratory techniques. These prostheses are undergoing clinical trials with encouraging results.

[The effect of RET's group learning program on irrational beliefs and health condition of the elderly]

This study was to explore the effect of RET's group learning program on improving irrational beliefs and the health condition of the elderly people. There were three major purposes: (1) design a set of group learning programs which are suitable for the native elderly; (2) explore the treatment effect of group learning program on improving their irrational beliefs and health; and verify the effect of the group learning program; and (3) explore the follow-up effect of the group learning program on their rational beliefs and health. The subjects were 51 elderly (66-80 years old), divided into treatment group A (Taiwanese), treatment group B (Mandarin) and control group. There were 17 subjects in each group. Instruments used in the study were the irrational Belief Scale, the Mental Health Scale, and the Life Satisfaction Scale, the Coping Strategies Scale, the Disease Checklist and Symptom Checklist. After pretesting treatment groups A and B were instructed in the group learning program twelve times in a period of six weeks. Then the treatment groups were given the post-test with the same instruments. After another six weeks, all subjects were given a follow-up tests. Data were analyzed by dependent sample t-test, repeated measure two-way ANOVA and one-way ANOVA. The main finding were as follow: 1. treatment effect (1) After the treatment of the group learning program, the elderly in groups A and B had a significant improvement (P < .001) with 14 items for irrational belief, mental health, life satisfaction, coping strategies, physical disease and physical symptom. (2) The difference of treatment effect between treatment groups was not significant (P > .05). This result shows that the language mode in which the learning program was presented was not a significant factor. 2. follow-up effect The 12 items of irrational belief, mental health, physical disease, and physical symptoms of the treatment groups were significantly better than in the control group except the factor of reproaching badness. There was no difference among the three groups in life satisfaction and coping strategies. This study affirmed the effect of the group learning program on improving irrational beliefs and health condition of the elderly.

Polyethylene fibre reinforced poly(methylmethacrylate)--water sorption and dimensional changes during immersion

The reinforcement of acrylic denture base resin with high performance polyethylene fibre in chopped, woven and continuous parallel forms resulted in significant reductions in water sorption and dimensional changes during immersion. The dimensional changes during immersion mainly occur during the non-steady state of the diffusion process.

Processing shrinkage of heat-curing acrylic resin reinforced with high-performance polyethylene fibre

The incorporation of high-performance polyethylene fibre into acrylic denture-base resin produced a very significant decrease in the processing shrinkage of the material, explained by the highly anisotropic mechanical and thermal properties of the fibres.

Acrylic resin reinforced with chopped high performance polyethylene fiber--properties and denture construction

A newly developed incremental mixing technique has been used to incorporate over 30 vol % chopped high performance polyethylene fiber into acrylic denture base resin. The reinforcement produced a substantial improvement in several clinically important properties, namely: 1) stiffness and impact strength were higher; 2) the mechanical properties were insensitive to notches that mimic anatomical features; and 3) samples damaged during bending and impact did not break up into separate fragments. Reinforced complete maxillary and mandibular dentures of good esthetic appearance were successfully manufactured and polished with conventional laboratory techniques.

[Effect of Salvia miltiorrhiza on the cardial ischemia in rats induced by ligation]

I.p. injection (5 g crude drug/kg) of water extract of Salvia miltiorrhiza to S.D. rats can prevent the acute cardial ischemia induced by the ligation of the coronary artery. The elevation of S-T segment in the electrocardiogram caused by the ischemia was greatly reduced in animals treated with Salvia miltiorrhiza compared with control group. The ischemia area in the left ventricle was significantly reduced and survival rate of the rats increased.

[Protective action of Salvia miltiorrhiza aqueous extract on chemically induced acute myocardial ischemia in rats]

Aqueous extract of Salvia miltiorrhiza (SM-H) can protect the acute myocardial ischemia and arrhythmia of Sprague-Dawley rats induced by isoproterenol (ISO) or BaCl2 with the following results: (1) intraperitoneal injection (i.p.) of SM-H for 3 to 5 days or intravenously (i.v.) just once significantly reduced the death rate of the animals, (2) i.v. SM-H pretreatment significantly increased the lethal dose of BaCl2 infusion, (3) i.p. SM-H significantly decreased premature ventricular contraction, ventricular fibrillation, bradycardia and mortality rate induced by bolus i.v. of BaCl2, and (4) i.p. SM-H also significantly reduced ECG J-point displacement of rats induced by ISO.

Optical generation of a circular harmonic filter for rotation and translation invariant optical pattern recognition

A new method to generate a circular harmonic filter with both rotation and translation invariance is described, which is based on a phase-shifted double-exposure (PSDE) technique. An expression for the peak correlation intensity at the origin of the correlation plane as a function of target orientation for the PSDE filter is derived. Experimental results confirming the theoretical predictions are provided.