Contribution of the PDL to Osteotomy Repair and Implant Osseointegration

Our objective was to clarify the fate of the periodontal ligament (PDL) retained in the socket after tooth extraction, then determine if this tissue contributed to the osseointegration of "immediate" implants placed in these fresh extraction sockets. Mice underwent maxillary first molar extraction, the residual PDL was removed by an osteotomy, and titanium implants were placed. The osteotomy was created in such a way that the palatal surface was devoid of PDL remnants while the buccal, mesial, and distal surfaces retained PDL fibers. At multiple time points after surgery, tissues were analyzed using a battery of molecular, cellular, and histomorphometrical assays. We found that PDL remnants mineralized and directly contributed to new bone formation in the extraction site. Compared with regions of an extraction site where the PDL was removed by osteotomy, regions that retained PDL fibers had produced significantly more new bone. Around immediate implants, the retained PDL remnants directly contributed to new bone formation and osseointegration. Thus, we conclude that PDL remnants are inherently osteogenic, and if the tissue is healthy, it is reasonable to conclude that curetting out an extraction socket prior to immediate implant placement should be avoided. This recommendation aligns with contemporary trends toward minimally invasive surgical manipulations of the extraction socket prior to immediate implant placement.

Chronic subdural hematoma management: clarifying the definitions of outcome measures to better understand treatment efficacy - a systematic review and meta-analysis

OBJECTIVE

A long history of inconsistencies in the definitions of the outcome measures for chronic subdural hematomas (CSDHs) has contributed to the controversy over the optimal surgical strategy for CSDH treatment. Clarifying these definitions, reassess the available data, and systematically review the prior literature may provide better insight into the differences in treatment efficacy for CSDH.

MATERIALS AND METHODS

The clinical course of CSDH was described with a series of strictly defined outcome measures. PubMed, Cochrane Library, and ScienceDirect databases were searched for comparative studies of two main surgical techniques for CSDH, including burr hole craniotomy (BHC) and twist drill craniotomy (TDC). Data were collected with uniform criteria and analyzed using a random-effects model to estimate the mortality, recurrence, operative failure, and cure rates of each treatment.

RESULTS

Twelve comparative studies that examined 2,027 CSDH patients were included. The analysis results indicated that TDC and BHC treatments were similar in the mortality rates (RR, 1.25; 95% CI, 0.83-1.87; I2 = 0%; p = 0.28) and the recurrence rates (RR, 1.29; 95% CI, 0.87-1.92; I2 = 13%; p = 0.21) for CSDH patients. However, TDC had a significantly higher operative failure rate compared with BHC (RR, 0.35; 95% CI, 0.15-0.83; I2 = 0%; p = 0.02), whereas patients treated by a TDC approach tended to achieve higher cure rates compared with BHC (RR, 0.92; 95% CI, 0.86-0.99; I2 = 55%; p = 0.02).

CONCLUSIONS

The clarification of the definitions related to CSDH outcome facilitates the interpretation of differences in treatment efficacy. The TDC approach manifested a significantly higher operative failure rate compared with the BHC approach; however, TDC showed a tendency in achieving a long-term neurologic cure.

Deformation and failure mechanisms of nanoscale cellular structures of metallic glasses

Cellular metallic glasses (MGs) can be good candidates for structural and functional applications due to their light weight, enhanced ductility and excellent energy absorption performance.

Sleep duration and snoring associate with hypertension and glycaemic control in patients with diabetes

AIMS

Few studies have analysed the effect of sleep duration and snoring on hypertension and glycaemic control in patients with diabetes. This study aims to investigate the relationship of sleep duration and snoring on prevalent hypertension and glycaemic control in people with diabetes.

METHODS

In the baseline survey of the REACTION study, 56 032 patients with diabetes were categorized into four groups according to self-reported sleep duration: < 6, 6-7.9, 8-8.9 and ≥ 9 h. Snoring frequency was evaluated as 'usually', 'occasionally' or 'never'. Hypertension was assessed by systolic blood pressure, diastolic blood pressure, self-reported previous diagnosis and antihypertensive medications. 'Good' glycaemic control was defined as HbA1c < 53 mmol/mol (7.0%) and 'poor' glycaemic control as HbA1c ≥ 53 mmol/mol (7.0%).

RESULTS

Controlling for potential confounders and intermediates, sleep ≥ 9 h relative to intermediate sleep (6-7.9 h) was significantly associated with prevalent hypertension (OR: 1.25, 95% CI: 1.18-1.32) and poor glycaemic control (OR: 1.11, 95% CI: 1.05-1.18), and a U-shaped association was found between sleep duration and prevalent hypertension (P for quadratic trend = 0.019). Usually snoring was positively associated with prevalent hypertension (OR: 1.30, 95% CI: 1.23-1.37), whereas the association between snoring and poor glycaemic control was only on the borderline of statistical significance.

CONCLUSIONS

Compared with a sleep duration of 6-7.9 h, longer sleep duration was associated with a higher prevalence of hypertension and poor glycaemic control in people with diabetes. Moreover, the relationship between sleep duration and prevalent hypertension was U-shaped. These findings may propose important public health implications for diabetes management.

Associations of depression with impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in Chinese adults

AIM

To examine the association between depression and impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in middle-aged and elderly Chinese people, and whether depression was associated with different treatment regimens or durations of diabetes.

METHODS

A cross-sectional study was performed among 229,047 adults living in the community aged ≥ 40 years from 25 centres in China. The self-reported depression rating scale Patient Health Questionnaire 9 (PHQ-9) was used to diagnose probable and sub-threshold depression. Glucose metabolism status was determined according to World Health Organization 1999 diagnostic criteria.

RESULTS

The numbers of participants with normal glucose regulation, impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes were 120,458, 59,512, 24,826 and 24,251, respectively. The prevalence of sub-threshold depression in the total sample of participants was 4.8% (4.8%, 4.8%, 4.4% and 5.6% from normal glucose regulation to previously diagnosed diabetes, respectively), and the prevalence of probable depression was 1.1% (1.1%, 1.0%, 0.9% and 1.8% from normal glucose regulation to previously diagnosed diabetes, respectively). Compared with participants with normal glucose regulation, those with previously diagnosed diabetes had increased odds of probable depression [odds ratio (OR) = 1.61, 95% confidence interval (CI) 1.39-1.87] and sub-threshold depression (OR = 1.14, 95% CI 1.06-1.24), after adjustment for multiple confounding factors. Newly diagnosed diabetes or impaired glucose regulation was not associated with depression. Among those with previously diagnosed diabetes, insulin treatment was associated with greater odds of depression compared with no treatment or oral anti-diabetic medicine.

CONCLUSION

Previously diagnosed diabetes, but not newly diagnosed diabetes or impaired glucose regulation, was associated with a higher prevalence of depression. Patients receiving insulin were more likely to have depression than those not receiving treatment or being treated with oral anti-diabetic medicine.

MRI assessment of paraspinal muscles in patients with acute and chronic unilateral low back pain

OBJECTIVE

To investigate the changes in paraspinal muscle cross-sectional area (CSA) and composition, using the digital data from lumbar spine MRIs of patients with acute and chronic low back pain (LBP).

METHODS

In total, 178 patients with unilateral LBP who had lumbar MRI examination were recruited. The data were obtained by a retrospective documentation audit. The CSAs and mean signal intensities of the bilateral paraspinal muscles [psoas major (PM), quadratus lumborum, multifidus (MF) and erector spinae (ES)] were measured, and the percentage of fat infiltration was calculated. The data between the painful side and non-painful side were compared, and between-group comparisons were tested. 42 patients with chronic unilateral LBP could indicate the problem level, and the CSA and mean signal intensity of the MF muscle were analysed at the problem level, and one vertebral above and one vertebral level below the problem level.

RESULTS

The CSAs of the PM and ES muscles were significantly decreased in the acute LBP group, while in the chronic LBP group, significant reduction in CSA was found in the MF and ES muscles on the painful side compared with the non-painful side. The mean signal intensity and fat content of the ES muscle on the painful side in the chronic LBP group was significantly higher than that on the painful side in the acute LBP group. The significant decrease of CSA in the MF muscle was found at multiple levels on the painful side.

CONCLUSION

The present findings show that there is selective ipsilateral atrophy of paraspinal muscles, specific to the symptomatic side, in patients with acute and chronic LBP. The reduction of the muscle CSA and increased fatty infiltration occurred synchronously, and the extent of change is significantly greater in chronic LBP in the ES muscle. Atrophy of the MF muscle appears to be at multiple levels but side specific in relation to symptoms in patients with chronic LBP, and the decreased muscle CSA may occur prior to fatty infiltration.

ADVANCES IN KNOWLEDGE

There are specific paraspinal muscles undergoing atrophy and fatty infiltration in patients with acute and chronic LBP on the symptomatic side. The CSA of the MF muscle decreased at multiple levels on the symptomatic side in patients with chronic unilateral LBP, which may occur prior to fatty infiltration.

Regression to normoglycaemia by fenofibrate in pre-diabetic subjects complicated with hypertriglyceridaemia: a prospective randomized controlled trial

AIMS

Lipotoxicity has recently been shown to be an important risk factor underlying the pathogenesis of pre-diabetes. However, clinical evidence supporting the treatment of pre-diabetes by improving lipotoxicity is lacking. Here, we conducted an open-label, randomized, controlled trial to investigate whether fenofibrate, the widely used hypolipidaemic agent, might benefit pre-diabetes, with metformin and diet control, the recommended intervention methods, as positive controls.

METHODS

Newly diagnosed pre-diabetes patients (n = 120) with hypertriglyceridaemia (plasma triglyceride levels between 1.8 and 4.5 mmol/l) were randomly assigned by computer-generated randomization sequence to either control group (no intervention), fenofibrate group (200 mg once a day), metformin group (500 mg three times a day) or diet-controlled group (diet recommendation). Plasma biochemistry examination was performed every 2 months. The primary endpoint was the outcome of the natural course of pre-diabetes, evaluated by oral glucose tolerance test after 6-month follow-up.

RESULTS

Twenty subjects in the fenofibrate group, 24 subjects in the metformin group and 25 subjects in both the diet-controlled group and the control group finished the trial. Fenofibrate, metformin and diet control had protective effects on hypertriglyceridaemic pre-diabetes, evidenced by 53.3, 70 and 30% participants regressed to normoglycaemia, respectively. The effects of fenofibrate and metformin were comparable (P > 0.05), while diet control was less effective (P < 0.05). Liver damage occurred in six subjects in the fenofibrate group and gastrointestinal symptoms occurred in four subjects in the metformin group. No serious adverse events occurred.

CONCLUSION

Controlling lipotoxicity by fenofibrate could effectively ameliorate the natural course of hypertriglyceridaemic pre-diabetes.

Estimating mercury emissions from a zinc smelter in relation to China's mercury control policies

Mercury concentrations of flue gas at inlet/outlet of the flue gas cleaning, electrostatic demister, reclaiming tower, acid plant, and mercury contents in zinc concentrate and by-products were measured in a hydrometallurgical zinc smelter. The removal efficiency of flue gas cleaning, electrostatic demister, mercury reclaiming and acid plant was about 17.4%, 30.3%, 87.9% and 97.4% respectively. Flue gas cleaning and electrostatic demister captured 11.7% and 25.3% of the mercury in the zinc concentrate, respectively. The mercury reclaiming tower captured 58.3% of the mercury in the zinc concentrate. About 4.2% of the mercury in the zinc concentrate was captured by the acid plant. Consequently, only 0.8% of the mercury in the zinc concentrate was emitted to the atmosphere. The atmospheric mercury emission factor was 0.5 g t(-1) of zinc produced for the tested smelter, indicating that this process offers the potential to effectively reduce mercury emissions from zinc smelting.

Influence of eutrophication on the distribution of total mercury and methylmercury in hydroelectric reservoirs

The distribution of mercury (Hg) and the characteristics of its methylation were investigated in Wujiangdu (WJD) and Yinzidu (YZD) reservoirs in Guizhou province, China. The two reservoirs are characterized by high and low levels of primary productivity, respectively. Mercury species in water samples from depth profiles in both reservoirs and from interface water in the WJD were analyzed each season during 2007. The concentrations of total Hg (HgT(unf)) and methylmercury (MeHgT(unf)) in unfiltered water samples from the WJD varied from 3.0 to 18 pmol dm(-3) and from 0.17 to 15 pmol dm(-3), respectively; ranges were 2.0 to 9.5 pmol dm(-3) for HgT(unf) and 0.14 to 2.2 pmol dm(-3) for MeHgT(unf) in the YZD. Elevated methylmercury concentrations in water samples from the bottom water and water-sediment interface demonstrated an active net Hg methylation in the downstream reach of the WJD. There was no discernable Hg methylation occurring in the YZD, nor in the upstream and middle reaches of the WJD. The results suggest that high primary productivity resulting from cage aquaculture activities in the WJD is an important control on Hg methylation in the reservoir, increasing the concentrations of MeHg in water in the Wujiang River basin Southwestern China.

Effects of surfactant replacement on alveolar overdistension and plasma cytokines in ventilator-induced lung injury

BACKGROUND

Overdistension of the lung causes ventilator-induced lung injury (VILI) accompanied by surfactant abnormalities and inflammatory changes. We investigated the effects of surfactant replacement on overdistension of the terminal airspaces and plasma cytokine levels in VILI.

METHODS

VILI was induced by high-pressure ventilation (HPV) in rats anesthetized with pentobarbital, followed by ventilation for 2 h in the maintenance mode (tidal volume=10 ml/kg, positive end-expiratory pressure = 7.5 cmH(2)O) with or without surfactant replacement. The sizes of the terminal airspaces were determined after fixing the lungs at an airway pressure of 10 cmH(2)O on deflation. Cytokine levels were assessed by enzyme-linked immunosorbent assay.

RESULTS

The mean ratio of the largest terminal airspace size class (> or = 64,000 microm(2)) was increased from 13.4% to 32.0% by HPV (P<0.05). After maintenance-mode ventilation, the ratio decreased to 16.1% with surfactant replacement (P<0.05), but increased to 44.6% without surfactant replacement (P<0.05). Mean macrophage inflammatory protein-2 (MIP-2) levels in the plasma increased from <0.02 to 6.9 ng/ml with HPV (P<0.05), and further increased to > or = 11.8 ng/ml, regardless of surfactant replacement after maintenance-mode ventilation. Similar tendencies were observed in the interleukin (IL)-6 and IL-10 levels. Tumor necrosis factor-alpha levels were almost negligible during the experiment.

CONCLUSION

In rats with VILI, surfactant replacement reversed overdistension of the terminal airspaces that may induce barotrauma, but not upregulation of MIP-2, IL-6, and IL-10 within 2 h.

Prospective study of T cell receptor utilization following the induction of murine thyroiditis

Murine experimental autoimmune thyroiditis (EAT) is a well established model of autoimmune disease initiated by immunization with thyroglobulin. We have previously analyzed the T cell receptor (TcR) V gene families used by the intrathyroidal lymphocytic infiltrate in CBA/J mice with well established thyroiditis EAT and have implicated T cells expressing the mTcR V beta 13 gene family. We have now proceeded to examine the time course of mTcR V gene family use following immunization with mTg. We used a radiolabelled RT-PCR technique with oligonucleotides detecting 17 mouse TcR V beta gene families to examine the heterogeneity of the amplified V-D-J (CDR3) fragments. As previously, the TcR V beta 13 amplifications showed the expression of two similar homogeneous CDR3 sizes consistent with two clonally expanded T cell populations. However, such T cell clonal expansion was observed to peak at day 25 and by 90 days had markedly diminished despite the continuing presence of extensive histologic infiltration. An additional immunization with mTg at 63 days failed to maintain the mTcR V beta 13 clonal presence. Further confirmation of these observations was obtained by direct analysis of intrathyroidal T cells rescued from mice with EAT. Such intrathyroidal T cells, 25 days after mTg, demonstrated a marked increase in mTcR V13 expressing T cells to 9.4% compared to 2% of T cells in peripheral blood. It appeared, therefore, that in EAT the accumulation of V13 expressing T cells was a transient phenomenon which peaked at 25 days after immunization. The persistence of an intrathyroidal infiltration indicated that such T cells must have been accompanied by the accumulation and recruitment of additional selected bystander T cells. Such non-specific T cells may also have an integral role in the progression of autoimmune thyroiditis.

A combinatorial multicomponent plug mixer for systems chemistry

We report the construction and testing of a combinatorial multicomponent plug mixer (CMPM) chip that generates a large number of mix ratios. The CMPM chip has been designed to study ribonucleotide reductase (RNR) protein-protein/protein-ligand interaction networks. The 4-component chip is capable of 5400 different combinations in a 30 plug cycle. CMPM chips were tested producing fluorescent dye and dihydrofolate reductase NADPH/MX mixtures with plug lengths of 2 mm.

Sharing risk management: an implementation model for cardiovascular absolute risk assessment and management in Australian general practice

PURPOSE

Despite considerable work in developing and validating cardiovascular absolute risk (CVAR) algorithms, there has been less work on models for their implementation in assessment and management. The aim of our study was to develop a model for a joint approach to its implementation based on an exploration of views of patients, general practitioners (GPs) and key informants (KIs).

METHODS

We conducted six focus group (three with GPs and three with patients) and nine KI interviews in Sydney. Thematic analysis was used with comparison to highlight the similarities and differences in perspectives of participants.

RESULTS

Conducting CVAR was seen as more acceptable for regular patients rather than new patients for whom GPs had to attract their interest and build rapport before doing so at the next visit. GPs' interest and patients' positive attitude in managing risk were important in implementing CVAR. Long consultations, good communication skills and having a trusting relationship helped overcome the barriers during the process. All the participants supported engaging patients to self-assess their risk before the consultation and sharing decision making with GPs during consultation. Involving practice staff to help with the patient self-assessment, follow-up and referral would be helpful in implementing CVAR assessment and management, but GPs, patients and practices may need more support for this to occur.

CONCLUSIONS

Multiple strategies are required to promote the better use of CVAR in the extremely busy working environment of Australian general practice. An implementation model has been developed based on our findings and the Chronic Care Model. Further research needs to investigate the effectiveness of the proposed model.

Cardiovascular risk management and its impact in Australian general practice patients with type 2 diabetes in urban and rural areas

OBJECTIVE

To investigate the cardiovascular disease (CVD) risk management and its impact on Australian general practice patients with type 2 diabetes in urban and rural areas between 2000 and 2002, and to compare trends over time and differences between urban and rural areas.

DESIGN AND METHODS

Population-based repeated cross-sectional study. 6305 patient records from 2000 to 2002 were extracted from registers of diabetes type 2 patients held by 16 Divisions of General Practice (250 practices) across Australia. Multivariate logistic regression comparing urban and rural patients at differing time-periods and comparing trend changes was conducted using multilevel analysis.

RESULTS

Prescribing of antihypertensive and lipid-lowering medications was infrequent but increased in both urban and rural areas from 2000 to 2002 (p<0.05), while attendance at other allied health professionals did not. While the proportion of patients meeting targets for high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol increased in both areas over time, only in urban areas were there improvements in total cholesterol and blood pressure over time. The proportion of patients meeting targets for HDL-C, triglycerides and smoking cessation were higher in urban areas than in rural areas by 2002.

CONCLUSIONS

Despite a number of national initiatives to improve general practice care and specifically support better care in rural areas, cardiovascular risk management and its impact in Australian general practice patients with type 2 diabetes was still suboptimal during the study period especially among patients from rural areas. Greater effort will be required to reduce the disparity in risk factor prevention for CVD between urban and rural people with type 2 diabetes in Australia.