Expression of a cytokine, interleukin-23, in experimental periapical lesions

AIM

To investigate the expression of interleukin (IL)-23, a new member of the IL-12 family, in experimental periapical lesions.

METHODOLOGY

Periapical lesions were induced in Wistar rats by occlusal surface pulp exposure in mandibular first molars. The rats were randomly sacrificed 0, 7, 14, 21, 28, 35, 42 and 56 days after pulp exposure. The jaws that contained the first molars were obtained and routinely prepared for radiographic, histological, enzyme histochemical, immunohistochemical and double immunofluorescence analyses. Data were analysed by one-way analysis of variance and the Pearson correlation test.

RESULTS

The number of IL-23-positive cells increased from day 7 to day 35 and then gradually decreased. The number of osteoclasts increased and peaked on day 14 and then gradually decreased from day 21 to day 56. A significant positive correlation existed between the number of IL-23 positive cells and the size of bone resorption in periapical lesions from day 7 to day 56 (r = 0.875, P < 0.01).

CONCLUSIONS

Interleukin-23 can be observed and may be associated with inflammatory response and bone resorption in periapical lesions.

Comparison of spermatogenic damage induced at 6 months after ligation of the vas deferens at proximal and distal locations in the rabbit

Recent study in rabbits demonstrated that vasectomy via the inguinal canal did not result in any spermatogenic damage 3 months postoperation; this study aimed to determine whether the damage would occur in a longer term. The left or right vas deferens was ligated near the epididymal head (unilateral proximal vasectomy, 12 animals) or via the inguinal canal (unilateral distal vasectomy, 11 animals) in adult male rabbits, with a sham operation being performed on the contralateral side. Six months postoperation, testes, epididymides and vasa deferentia were removed and methacrylate resin-embedded sections prepared to evaluate spermatogenesis by histological (qualitative) and stereological (quantitative) studies. The juxta-epididymal segment of the occluded vas deferens was severely distended (filled with sperm) in 10 of the 11 animals with distal vasectomy and moderately or slightly distended in nine of the 12 animals with proximal vasectomy. Severe spermatogenic damage occurred in seven animals with proximal vasectomy (the juxta-epididymal vas moderately or slightly distended), in only one animal with distal vasectomy (the vas not severely distended). In conclusion, spermatogenic damage occurred at 6 months postvasectomy in some animals, especially those with proximal vasectomy and therefore shorter occluded reproductive tract for sperm storage; the damage was probably intra-tract pressure mediated.

The prevalence of and risk factors for non-carious cervical lesions in adults in Hubei Province, China

OBJECTIVES

To describe the prevalence of non-carious cervical lesions (NCCLs) and to assess the relative affects of risk factors on NCCLs in middle-aged and elderly people in Hubei Province, China.

DESIGN

A sample of 2,160 adults, aged 35-44 years and 65-74 years and balanced by age, gender, and urbanization, participated in the cross sectional epidemiological survey. Non-carious cervical lesions were examined using a modified Tooth Wear Index. Data were collected based on structured questionnaires that assessed general information as well as oral health.

RESULTS

The prevalence of non-carious cervical lesions was 38.8% for 35-44-year-olds and 56.6% for 65-74-year-olds. The first premolars, canines, and second premolars showed the highest prevalence of lesions, while the second molars demonstrated the least. Several risk factors such as age (OR = 2.45, p < 0.001), location (OR = 1.68, p = 0.001), frequency of toothbrushing (OR = 1.33, p = 0.016), bruxism (OR = 1.37, p < 0.001), and family income (OR = 1.44, p < 0.001) were found to be associated with lesion occurrence.

CONCLUSIONS

The prevalence of non-carious cervical lesions was relatively high in the middle-aged and elderly persons in China and was also associated with socio-behavioural risk factors.

Using Ascertainment for Targeted Resequencing to Increase Power to Identify Causal Variants

Researchers continue to use genome-wide association studies (GWAS) to find the genetic markers associated with disease. Recent studies have added to the typical two-stage analysis a third stage that uses targeted resequencing on a randomly selected subset of the cases to detect the causal single-nucleotide polymorphism (SNP). We propose a design for targeted resequencing that increases the power to detect the causal variant. The design features an ascertainment scheme wherein only those cases with the presence of a risk allele are selected for targeted resequencing. We simulated a disease with a single causal SNP to evaluate our method versus a targeted resequencing design using randomly selected individuals. The simulation studies showed that ascertaining individuals for the targeted resequencing can substantially increase the power to detect a causal SNP, without increasing the false-positive rate.

Effect of alendronate on alveolar bone resorption and angiogenesis in rats with experimental periapical lesions

AIM

To investigate the effects of systemically administered alendronate, one of the most potent bisphosphonates (BPs), on alveolar bone resorption and angiogenesis in rats subjected to experimental periapical lesions over two time periods.

METHODOLOGY

Forty adult Sprague-Dawley (SD) rats were divided equally into control and experimental groups, and the pulp chambers of mandibular first molars of all rats were exposed to the oral environment to induce periapical lesions. The experimental group received daily subcutaneous injections of alendronate at a dose of 0.25 mg kg(-1), whereas the control group received only the saline vehicle. These injections were initiated 1 week before the periapical lesion induction and then continued daily throughout the entire experimental period. After 2 or 4 weeks following pulp exposure, the rats were killed, and the mandibles were examined histologically for periapical bone loss area, number of microvascular vessels (NMV) and tartrate-resistant acid phosphatase (TRAP) activity.

RESULTS

Overall, periapical bone loss area and the number of TRAP-positive cells (osteoclasts) were significantly decreased at 2 and 4 weeks, respectively, after daily subcutaneous injection of alendronate compared with the control group (P < 0.05). There was no significant decrease change in NMV (P > 0.05).

CONCLUSIONS

Administration of alendronate to rats might inhibit alveolar bone resorption associated with periapical disease, which might not lead to impairment of angiogenesis. However, because of the differences between rats and humans, one has to consider the possible consequences of this treatment in the clinic.

Significance of perihematomal edema in acute intracerebral hemorrhage: the INTERACT trial

BACKGROUND

Uncertainty surrounds the effects of cerebral edema on outcomes in intracerebral hemorrhage (ICH).

METHODS

We used data from the INTERACT trial to determine the predictors and prognostic significance of "perihematomal" edema over 72 hours after ICH. INTERACT included 404 patients with CT-confirmed ICH and elevated systolic blood pressure (BP) (150-220 mm Hg) who had the capacity to commence BP lowering treatment within 6 hours of ICH. Baseline and repeat CT (24 and 72 hours) were performed using standardized techniques, with digital images analyzed centrally. Predictors of growth in edema were determined using generalized estimating equations, and its effects on clinical outcomes were estimated using a logistic regression model.

RESULTS

Overall, 270 patients had 3 sequential CT scans available for analyses. At baseline, there was a highly significant correlation between hematoma and perihematomal edema volumes (r(2) = 0.45). Lower systolic BP and baseline hematoma volume were independently associated with absolute increase in perihematomal edema volume. History of hypertension, baseline hematoma volume, and earlier time from onset to CT were independently associated with relative increase in edema volume. Both absolute and relative increases in perihematomal edema growth were significantly associated with death or dependency at 90 days after adjustment for age, gender, and randomized treatment, but not when additionally adjusted for baseline hematoma volume.

CONCLUSIONS

The degree of, and growth in, perihematomal edema are strongly related to the size of the underlying hematoma of acute intracerebral hemorrhage, and do not appear to have a major independent effect in determining the outcome from this condition.

Six-year incidence of lower extremity arterial disease and associated risk factors in Type 1 diabetic African-Americans

AIMS

To report the 6-year incidence of, and risk factors for, lower extremity arterial disease (LEAD) in African-Americans with Type 1 diabetes mellitus.

METHODS

African-Americans (n = 483) with Type 1 diabetes were re-examined 6 years after an original visit. At both visits, patients underwent a structured clinical interview which included history of amputation or leg angioplasty because of poor circulation in lower extremities; ocular examination; masked grading of seven stereoscopic fundus photographs; and blood pressure measurements. Biological tests included blood and urine assays.

RESULTS

Of the 483 patients who had a 6-year follow-up, 457 had no LEAD at the baseline examination. Of these 457 patients, 26 (5.7%) developed LEAD over the 6-year follow-up. Six-year incidence of LEAD was significantly associated with baseline older age (P = 0.0002) and longer duration of diabetes (P < 0.0001). Multiple logistic regression analysis showed that baseline longer duration of diabetes, male gender, higher systolic blood pressure, retinopathy severity, and presence of foot ulcers were significant and independent risk factors for incidence of LEAD.

CONCLUSIONS

Blood pressure control and prevention and treatment of foot ulcers may be helpful in reducing the morbidity associated with LEAD in African-Americans with Type 1 diabetes.

The ischemic preconditioning paradox in deceased donor liver transplantation-evidence from a prospective randomized single blind clinical trial

While animal studies show that ischemic preconditioning (IPC) is beneficial in liver transplantation (LT), evidence from few smaller clinical trials is conflicting. From October 2003 to July 2006, 101 deceased donors (DD) were randomized to 10 min IPC (n = 50) or No IPC (n = 51). Primary objective was efficacy of IPC to decrease reperfusion (RP) injury. Both groups had similar donor risk index (DRI) (1.54 vs. 1.57). Aminotransferases on days 1 and 2 were significantly greater (p < 0.05) in IPC recipients. In multivariate analyses, IPC had an independent effect only on day 2 aspartate transferase. Prothrombin time, bilirubin and histological injury were similar in both groups. IPC had no significant effect on plasma TNF-alpha, IL-6 and IL-10 in the donor and TNF-alpha and IL-6 in the recipient. In contrast, IPC recipients had a significant rise in systemic IL-10 levels after RP (p < 0.05) and had fewer moderate/severe rejections within 30 days (p = 0.09). Hospital stay was similar in both groups. One-year patient and graft survival in IPC versus No IPC were 88% versus 78% (p = 0.1) and 86 versus 76% (p = 0.25), respectively. IPC increases RP injury after DDLT, an 'IPC paradox'. Other potential benefits of IPC are limited. IPC may be more effective in combination with other preconditioning regimens.

Risk factors for coronary disease and stroke in previously hospitalized African-Americans with Type 1 diabetes: a 6-year follow-up

AIMS

To report the 6-year incidence of, and risk factors for, cardiovascular disease (CVD), either coronary disease or stroke, in previously hospitalized African-Americans with Type 1 diabetes mellitus.

METHODS

African-Americans (n = 483) with Type 1 diabetes were re-examined as part of a 6-year follow-up. At both visits, patients underwent a structured clinical interview, which included history of either coronary disease or stroke, ocular examination and masked grading of seven stereoscopic fundus photographs, blood pressure measurements, and administration of the Beck Depression Inventory. Biological measurements included blood and urine assays.

RESULTS

Of the 483 patients who had a 6-year follow-up, 449 had no evidence of CVD at the baseline examination. Of these 449 patients, 51 (11.4%) developed any CVD-42 (9.3%) coronary disease and 14 (3.1%) a stroke. Six-year incidence of any CVD was significantly associated with older age (P < 0.0001) and longer duration of diabetes (P < 0.0001) at baseline. Multiple logistic regression showed that baseline older age, higher body mass index, higher diastolic blood pressure, proteinuria, retinopathy severity and being depressed were significant and independent risk factors for incidence of any CVD.

CONCLUSION

Six-year incidence of CVD is high in previously hospitalized African-Americans with Type 1 diabetes. Risk factors appear to include older age, higher body mass index, higher diastolic blood pressure, proteinuria, retinopathy severity and depression.

Infection of HeLa cells by avian infectious bronchitis virus is dependent on cell status

To investigate the adaptation of avian infectious bronchitis virus (IBV) in a human cell line may be beneficial to understanding the potential mechanisms of coronavirus interspecies infection. The current study addressed the poor replication of IBV in the HeLa human cell line demonstrated in previous reports. We showed that IBV strains M41, H52, H120 and Gray could be propagated in HeLa cells with distinct cytopathic effect. The virus titre in freshly dispersed HeLa cells was 1000-fold higher than in cell monolayers. Trypsin was not the determinant for the viral replication, suggesting that the restriction of IBV replication in HeLa cells is the result of intracellular events rather than the binding to or fusion with host cells. These IBV strains replicated to an average titre of 10(3.4+/-0.2)/0.1 ml median tissue culture infectious doses in freshly dispersed HeLa cells and maintained this titre for the first 12 passages. Then an approximately 10-fold increase (10(4.20+/-0.19)/0.1 ml) occurred in passage 13, which was maintained to passage 16, after which there was another, bigger rise to 10(6.6+/-0.3)/0.1 ml in passage 17. This titre was maintained until passage 24 when the experiment was terminated. The IBV M41 S1 gene was amplified and sequenced for passages 0, 5 and 21. There was only one amino acid replacement in the S1 protein, in passage 21. The presence of sialic acid on HeLa cells contributed to efficient virus replication, while human aminopeptidase N was not involved in the infection. Haemagglutinin activity gradually reduced with increased passages. These results indicated that the virus adaptation would probably be determined by host cell modification such as receptor glycosylation and different receptor utilization instead of viral gene mutation.

Molecular consequences of SOD2 expression in epigenetically silenced pancreatic carcinoma cell lines

Manganese superoxide dismutase (SOD2) is an enzyme that catalyses the dismutation of superoxide in the mitochondria, leading to reduced levels of reactive oxygen species. Reduced expression levels of SOD2 have been shown to result in increased DNA damage and sod2 heterozygous mice have increased incidences of cancer. It has also been shown that SOD2 expression is lost in pancreatic cell lines, with reintroduction of SOD2 resulting in decreased rate of proliferation. The mechanism of decreased SOD2 expression in pancreatic carcinoma has not been previously determined. We demonstrate, through sodium bisulphite sequencing, that the sod2 locus is methylated in some pancreatic cell lines leading to a corresponding decrease in SOD2 expression. Methylation can be reversed by treatment with zebularine, a methyltransferase inhibitor, resulting in restored SOD2 expression. Furthermore, we demonstrate that sensitivity of pancreatic carcinoma cell lines to 2-methoxyestradiol correlates with SOD2 expression and SOD2 modulation can alter the sensitivity of these cells. Using both genomics and proteomics, we also identify molecular consequences of SOD2 expression in MIA-PaCa2 cells, including dephosphorylation of VEGFR2 and the identification of both SOD2-regulated genes and transcription factors with altered binding activity in response to SOD2 expression.

Characterization of the adsorption of Ru-bpy dyes on mesoporous TiO2 films with UV-Vis, Raman, and FTIR spectroscopies

In the present work the adsorption of a new dye, [Ru(dcbpyH(2))(2)(bpy-TPA(2))](PF(6))(2), and the well-known (Bu(4)N)(2)[Ru(dcbpyH)(2)(NCS)(2)] complex on mesoporous anatase films were investigated to clarify the role of the carboxylate groups in the anchoring process of the dyes on the semiconductor surface. For this purpose UV-vis, Raman, resonance Raman, and ATR-FTIR spectroscopies have been used. The results of the Raman experiments at different excitation wavelengths demonstrate that photoinduced charge-transfer processes take place efficiently between the adsorbate and the substrate. Moreover, this is the first time that the Raman spectrum of a Ru-bpy dye (in this case, the dye N719) adsorbed on TiO(2) has been obtained without the resonance condition, only by means of SERS enhancement. The coordination of both complexes on the TiO(2) paste films is proposed to occur via bidentate or bridging linkage.

Internet-based cognitive testing in multiple sclerosis

Cognitive impairment in multiple sclerosis is difficult to study because of the heterogeneity and variability of this disease. The gold standard for measurement of cognitive function in multiple sclerosis is a full battery of neurocognitive tests, which is time consuming and expensive. Some cognitive tests like the PASAT, a measure of working verbal memory and processing speed, have been proposed for screening and follow-up of cognitive function in clinical trials. We studied whether we could measure cognitive function in multiple sclerosis over the Internet. For this we used the Cognitive Stability Index (CSI)™, developed for persons with known or suspected primary central nervous system illness. The CSI was compared with formal neurocognitive testing (NPsych) and the PASAT in a cross-sectional study of 40 consecutive multiple sclerosis patients with subjective cognitive complaints. NPsych revealed that only 18 of the 40 patients (46%) were cognitively impaired. Although both the CSI and the PASAT were equalivalent in their specificity (86%), the CSI was significantly more sensitive than the PASAT (83% versus 28%). We conclude that the CSI, because of its availability over the Internet, has great potential as a tool for screening and follow up of cognitive function in multiple sclerosis. Multiple Sclerosis 2007; 13: 1011—1019. http://msj.sagepub.com

Influence of the solvent on the surface-enhanced raman spectra of ruthenium(II) bipyridyl complexes

In the present work a new dye, [Ru(dcbpyH2)2(bpy-TPA2)](PF6)2, and the well-known (Bu4N)2[Ru(dcbpyH)2(NCS)2] complex were investigated. The electronic transitions of both dyes showed solvatochromic shifts due to specific interactions of the ligands with the solvent molecules. The surface-enhanced Raman (SER) spectra of the dyes dissolved in water, ethanol, and acetonitrile were measured in silver and gold colloidal solutions. The results demonstrate that the dyes were adsorbed on the metallic nanoparticles in different ways for different solvents. It was also found that in the gold colloid, the aqueous solutions of both dyes did not produce any SERS signal, whereas in ethanolic solution the SERS effect was very weak. Deprotonation, H-bonding, and donor-acceptor interactions seem to determine these different behaviors. Our results indicate the important role of the charge-transfer mechanism in SERS.

Effect of smoking on imatinib pharmacokinetics

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Background: Smoking is a potent inducer of the cytochrome P450 1A2 isoenzyme (CYP1A2) and may therefore effect the pharmacokinetics (PK) of drugs metabolized by CYP1A2. Indeed, clinical studies with erlotinib (metabolized by CYP3A4 and also partly by CYP1A2) have shown a major increase in erlotinib clearance in smokers versus non-smokers. The effect of smoking on the PK of imatinib, which is also metabolized by CYP3A4 and partly by CYP1A2, is unknown. We aimed to study the effect of smoking on imatinib PK in order to explain a part of the interpatient variation. Methods: The effect of smoking on the PK parameters was analyzed in 34 patients with gastro-intestinal stromal tumors or soft tissue sarcoma included in the EORTC-STBSG phase I and phase II trials. This cohort included 9 smokers and 25 non-smokers. The daily smoking habits of the study patients were retrieved retrospectively from the patient’s record. PK parameters assessed with NONMEM, version V were clearance (Cl), distribution volume (V), elimination half life (T1/2) and the dose standardized area under the concentration curve (AUC). We considered a 40% reduction in imatinib exposure clinically relevant and this study is adequately powered to detect this difference. Results: The mean PK parameters in the smokers versus the non-smokers group ± SD were: Cl; 9.6 ± 5.5 L/h vs 9.2 ± 4.6 L/h, V; 216.5 ± 114.3 L vs 207.0 ± 116.9 L, T1/2; 16.1 ± 6.0 h vs 16.5 ± 6.0 h, AUC; 133.6 ± 71.0 ng.h/ml.mg vs 142.3 ± 84.0 ng.h/ml.mg. There was no significant difference in PK parameters observed between the smokers and the non- smokers. Conclusion: This retrospective study suggest that the PK of imatinib was not affected by smoking and therefore does not explain the large variation in imatinib PK.

No significant financial relationships to disclose.

Comparison of defects in ProTaper hand-operated and engine-driven instruments after clinical use

AIM

To compare the type of defects and mode of material failure of engine-driven and hand-operated ProTaper instruments after clinical use.

METHODOLOGY

A total of 401 hand-operated and 325 engine-driven ProTaper instruments were discarded from an endodontic clinic over 17 months. Those that had fractured were examined for plastic deformation in lateral view and remounted for fractographical examination in scanning electron microscope. The mode of fracture was classified as 'fatigue' or 'shear' failure. The lengths of fractured segments in both instruments were recorded. Any distortion in hand instrument was noted. Data were analysed using chi-square, Fisher's exact or Student's t-test, where appropriate.

RESULTS

Approximately 14% of all discarded hand-operated instruments and 14% of engine-driven instruments were fractured. About 62% of hand instruments failed because of shear fracture, compared with approximately 66% of engine-driven instruments as a result of fatigue (P < 0.05). Approximately 16% of hand instruments were affected by shear, and either remained intact or was fractured, compared with 5% of engine-driven instruments (P < 0.05). The length of the broken fragment was significantly shorter in hand versus engine-driven group (P < 0.05). Approximately 7% of hand instruments were discarded intact but distorted (rarely for engine-driven instruments); all were in the form of unscrewing of the flutes. The location of defects in hand Finishing instruments was significantly closer to the tip than that for Shaping instruments (P < 0.05).

CONCLUSIONS

Under the conditions of this study (possibly high usage), the failure mode of ProTaper engine-driven and hand-operated instruments appeared to be different, with shear failure being more prevalent in the latter.

Therapeutic protein production in vivo after electroporation-assisted intramuscular gene delivery

Gene delivery to skeletal muscles assisted by electroporation(EP) is a promising strategy for in vivo production of the therapeutic proteins. But the commonly used procedure required the application of electric pulses with voltages at above 200V/cm and durations at least 40ms, which would result in several damages in the muscle and limited surviving cells expressing transgene. We reported here an optimization study of the various electric pulse parameters to reduce toxicity while maintain transgene expression. In addition, we also found that the secreted transgene product level detected in serum samples may not correlate with the total gene expression level in muscles. Based on our data, we'd propose some less damaging electroporation parameters that may be useful for intramuscular gene delivery and therapeutic protein production.

Impact of Lotensin and Salviae on the changes of TGF-beta1 and its receptors in a rat model of chronic cyclosporine-induced nephropathy

OBJECTIVES

Transforming growth factor-beta(1) (TGF-beta(1)) and its receptors, type 1 (TR-1) and type 2 (TR-2) play important roles in chronic cyclosporine (CsA)-induced nephropathy. Lotensin is known as an angiotensin-converting enzyme inhibitor and may reduce chronic CsA-induced nephropathy. Recently it is reported that Salviae (a Chinese medicine), which can improve microcirculation and decrease the expression of TGF-beta(1) has the same effect as that of lotensin. Therefore, in this study we assessed the effects of Lotensin or Salviae on the chronic CsA-induced upregulation of TGF-beta(1), TR-1, and TR-2 in a rat model.

MATERIALS AND METHODS

Sodium-depleted rats were administered CsA by gastric gavage and a new rat model of chronic CsA-induced nephropathy was established. Rats with chronic CsA-induced nephropathy were treated by lotensin or Salviae. The proteins of TGF-beta(1), TR-1, and TR-2, and the mRNA of TR-1 and TR-2 in the kidneys of CsA-treated rats, were measured by immunohistochemistry (IHC) and in situ hybridization (ISH). The results were investigated semiquantitatively by image analysis.

RESULTS

Lotensin or Salviae individually attenuated CsA-induced nephropathy in the rat models, and downregulated the protein expressions of TGF-beta(1), TR-1, and TR-2, and the mRNA transcripts of TR-1 and TR-2 in the rat model.

CONCLUSION

Our studies show that treatment with lotensin or Salviae is useful in preventing chronic CsA-induced nephropothy.

Potential role of estrogen receptor alpha (ERalpha) phosphorylated at Serine118 in human breast cancer in vivo

Post-translational modifications of proteins are known to be important in protein activity and ERalpha is known to be phosphorylated at multiple sites within the protein. The exact function of site-specific phosphorylation in ERalpha is unknown, although several hypotheses have been developed using site-directed mutagenesis and cell culture models. Targeting the ERalpha at the level of such post-translational modification pathways would be a new and exciting approach to endocrine therapy in breast cancer, but adequate knowledge is lacking with regard to the relevance of site-specific phosphorylation in ERalpha in human breast cancer in vivo. Recently, antibodies to P-Serine(118)-ERalpha and P-Serine(167)-ERalpha, two major sites of phosphorylation in ERalpha, have become available and some in vivo data are now available to complement studies in cells in culture. However, the in vivo data are somewhat contradictory and limited by the small cohorts used and the lack of standard well-characterized reagents and protocols.

Protective efficacy of a targeted anti-caries DNA plasmid against cariogenic bacteria infections

We have previously reported that a targeted anti-caries DNA plasmid pGJA-P/VAX which was constructed against the antigenic determinants of Streptococcus mutans (S. mutans) successfully induced antibody responses in mice and monkeys. The present study explored the protective efficacy of pGJA-P/VAX against cariogenic bacterial challenge. Groups of rats were orally challenged with S. mutans or Streptococcus sobrinus (S. sobrinus) and then immunized with pGJA-P/VAX or the vector pVAX1 intranasally. Serum IgG and salivary IgA antibody levels were assessed by an enzyme-linked immunosorbent assay and caries activity was evaluated by the Keyes method. The results showed that specific salivary IgA antibody responses were induced following intranasal vaccination with pGJA-P/VAX. Moreover, immunization with pGJA-P/VAX resulted in significantly reduced enamel and dentinal caries lesions in rats after S. mutans infection and significantly reduced enamel caries lesions after S. sobrinus infection. Thus, pGJA-P/VAX was not only protective toward S. mutans infection, but also provided cross-strain protection against S. sobrinus infection in rats.

The possible study of HuaXi-1 solution for all intra-abdominal organ preservation: a study in rats

OBJECTIVE

University of Wisconsin (UW) solution continues to be the most commonly used solution for intra-abdominal organs. However, it is expensive. Therefore, we have formulated HuaXi-1 (HX-1) solution. The aim of this research was to assess the effect of HX-1 solution compared to UW, Collins 2, and hypertonic citrate solutions on intra-abdominal organs.

METHODS

The effects of HX-1 solution for all intra-abdominal organ preservation were studied in a noncirculated, isolated, perfused rat liver model, in rat pancreas isografts in diabetic rats, and in a kidney autotransplant model. The effects were investigated by measuring hepatic tissue water content, sinusoidal lining cell mortality, Krebs-Henseleits perfusate, aspartate aminotransferase, the number of livers secreting bile during isolated perfusion, blood glucose, glucose tolerance tests, serum insulin of the rat pancreas-transplant recipients, the maximum serum creatinine levels, kidney graft survival rates, and observing the morphological changes in liver, pancreas, and kidneys.

RESULTS

HX-1 solution preserved rat liver well for 24 hours as effectively as UW, rat pancreas as well for 48 hours, and dog kidney as well for 72 hours.

CONCLUSION

The experimental findings indicated that HX-1 solution was effective to preserve all intra-abdominal organs; it may simplify cold storage of organs for transplantation.

The aggressive form of cherubism: report of two cases in unrelated families

Cherubism is a benign lesion that causes painless symmetrical enlargement of the jaws, usually with a familial tendency. We describe in two Chinese families two cases of the aggressive form of cherubism with extensive swelling on both sides of the mandible, typical microscopic findings, and apparent familial history.

Defects in ProTaper S1 instruments after clinical use: fractographic examination

AIM

To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface.

METHODOLOGY

A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test.

RESULTS

Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3+/-1.9 mm) was significantly greater than that for shear failure (2.5+/-0.8 mm) (P<0.001, two-sample t-test).

CONCLUSIONS

Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use.

Population pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia: results of a phase III study

AIMS

This study was designed to investigate the biochemical and physiological covariates or comedications that affect the pharmacokinetics of imatinib mesylate in patients with chronic-phase chronic myeloid leukaemia (CP CML).

METHODS

Pharmacokinetic data were analyzed in 371 patients receiving 400 mg imatinib once daily during a phase III trial of imatinib vs interferon-alfa plus cytarabine for the treatment of newly diagnosed CP CML. Covariates included age, weight, sex, ethnicity, haemoglobin (Hb) concentration, white blood cell (WBC) count, liver function, and creatinine concentration. Blood samples for imatinib analysis were taken on treatment days 1 and 29. Nonlinear mixed effects modelling was used for the population pharmacokinetic analysis.

RESULTS

Population mean estimates (95% confidence interval) at day 1 for apparent clearance (CL) and apparent volume of distribution (V) of imatinib were 14 (13-15) l h(-1) and 252 (237-267) l, respectively. Modelling suggested that CL decreased by 4 (3-5) l h(-1) from day 1 to day 29, whereas V remained unchanged. Interindividual variability in CL and V was 32% and 31%, respectively. Weight, Hb, and WBC count demonstrated small effects on CL and V. Doubling body weight or Hb or halving the WBC count was associated with a 12%, 86% and 8% increase in CL, respectively, and a 32%, 60% and 5% increase in V, respectively. Comedications showed no clear effects on imatinib CL.

CONCLUSIONS

Population covariates and coadministered drugs minimally affected imatinib pharmacokinetics in newly diagnosed CP CML patients.

Defects in ProTaper S1 instruments after clinical use: longitudinal examination

AIM

To evaluate defects in ProTaper shaping instrument S1 after a defined schedule of clinical use.

METHODOLOGY

Among all ProTaper files discarded from an endodontic clinic at a stomatological school in China over a period of 17 months, 122 S1 instruments were collected. They were ultrasonically cleaned, autoclaved and then examined in the laboratory. Any instrument separation was noted; the average length involved was determined. The 0.5 mm region on either side of this length of discarded but intact instruments was examined circumferentially by scanning electron microscope. The region adjacent to the broken end of the fractured instruments was also examined in the same way.

RESULTS

One specimen was lost during processing. Of the remaining 121 instruments, 27 were separated with a mean fracture length of 3.67 mm from the tip. Of these, two files showed macroscopically torsional fracture and the others showed signs of flexural fatigue. Only one file that had not fractured showed visible unwinding defects. Examination of the 3.1-4.1 mm region of other unfractured instruments revealed the presence of microcracks, surface debris, pitting and/or wear of their cutting edges. Some debris particles seemed to have been trapped in crack-like structures.

CONCLUSIONS

Multiple use of ProTaper S1 pre-disposed the instrument to microcrack formation and wear of the cutting edges. There was a low prevalence of plastic deformation and most ProTaper S1 instruments failed without discernible sign of unwinding of the flutes. Further studies should address the mode of failure and the role of debris particles in the fracture mechanism.

A novel locus for autosomal dominant hereditary gingival fibromatosis, GINGF3, maps to chromosome 2p22.3-p23.3

Hereditary gingival fibromatosis (HGF) is a rare, benign disorder characterized by slowly progressive fibrous overgrowth of the gingiva. To date, two loci have been mapped in familial cases with autosomal dominant non-syndromic HGF: GINGF (MIM 135300) on chromosome 2p21-p22 and GINGF2 (MIM 605544) on chromosome 5q13-q22. Of the two loci, only SOS1 (son of sevenless one, MIM 182530) gene underlying GINGF locus has been identified. Ascertainment of a large Chinese family has allowed the mapping of a novel locus to 2p22.3-p23.3, GINGF3. Haplotype construction and analysis localized the new locus to an 11.4-cM interval between markers D2S2221 (telomeric) and D2S1788 (centromeric). The maximum two-point limit of detection (LOD) score of 3.45 (theta=0) and multipoint LOD score of 5.00 for marker D2S390 strongly supported linkage to this region. Thus, this genetic interval is distal to and does not overlap with the previously described locus, GINGF, on 2p21-p22.

Inducible upregulation of oestrogen receptor-beta1 affects oestrogen and tamoxifen responsiveness in MCF7 human breast cancer cells

To investigate the effect of altered oestrogen receptor (ER)alpha and ERbeta expression on oestrogen and anti-oestrogen action in breast cancer, we have stably expressed an inducible ERbeta1 in MCF7 breast cancer cells. Stably expressing clones were isolated and over-expression of ERbeta1 correlated with increased levels of specific radiolabelled oestradiol (E2) binding. Increased ERbeta1 did not affect endogenous levels of ERalpha but increased progesterone receptor (PR) levels. Over-expression of ERbeta1 reduced growth responses to E2 in contrast to little if any effect of over-expression of ERalpha. In oestrogen-replete conditions, over-expression of ERbeta1 but not ERalpha reduced proliferation. Over-expression of ERbeta1 did not result in anti-oestrogen resistance but was associated with increased sensitivity to 4-hydroxytamoxifen. Our results suggested that over-expression of ERbeta1 in the presence of an endogenously expressed ERalpha was associated with tamoxifen sensitivity but may negatively modulate ERalpha-mediated growth. However, not all ERalpha activities were inhibited since endogenous PR expression was increased by both ERalpha and ERbeta1 over-expression. These data paralleled those seen in some in vivo studies showing a relationship between PR and ERbeta expression as well as ERbeta expression and tamoxifen sensitivity of ER-positive breast cancer patients. These models are relevant and will be useful for dissecting the role of ERbeta1 expression in ER-positive breast cancer.

The pathogenesis of discogenic low back pain

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament (NF200) and neuropeptides such as substance P (SP) and vasoactive-intestinal peptide (VIP) in the nerve fibres.

The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. SP-, NF- and VIP-immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.

Construction and immunogenic characterization of a fusion anti-caries DNA vaccine against PAc and glucosyltransferase I of Streptococcus mutans

Glucosyltransferases (GTFs) and A cell-surface protein (PAc) are two important virulence factors of the cariogenic organism Streptococcus mutans. They may mediate sucrose-independent or sucrose-dependent attachment of Streptococcus mutans to tooth surfaces, respectively. Thus, inhibiting both virulence factors is predicted to provide better protection against caries than inhibiting a single factor. To develop a highly efficient vaccine against caries, we constructed a fusion DNA vaccine, pGLUA-P, by cloning the GLU region of GTF into a DNA vaccine, pCIA-P, which encodes two highly conservative regions of PAc. In this report, we provide evidence that fewer caries lesions were observed in rats following subcutaneous injection of pGLUA-P, compared with pCIA-P, near the submandibular gland. Our findings suggest that a multigenic DNA vaccine may be more caries-preventive than a single-gene DNA vaccine.