Establishing and managing a periodontal biobank for research: the sharing of experience

Periodontal bio‐repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad‐based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.     

Ratiometric analysis in hyperpolarized NMR (I): test of the two‐site exchange model and the quantification of reaction rate constants

Conventional methods for the analysis of in vivo hyperpolarized ¹³C NMR data from the lactate dehydrogenase (LDH) reaction usually make assumptions on the stability of rate constants and/or the validity of the two‐site exchange model. In this study, we developed a framework to test the validity of the assumption of stable reaction rate constants and the two‐site exchange model in vivo via ratiometric fitting of the time courses of the signal ratio L(t)/P(t). Our analysis provided evidence that the LDH enzymatic kinetics observed by hyperpolarized NMR are in near‐equilibrium and satisfy the two‐site exchange model for only a specific time window. In addition, we quantified both the forward and reverse exchange rate constants of the LDH reaction for the transgenic and mouse xenograft models of breast cancer using the ratio fitting method developed, which includes only two modeling parameters and is less sensitive to the influence of instrument settings/protocols, such as flip angles, degree of polarization and tracer dosage. We further compared the ratio fitting method with a conventional two‐site exchange modeling method, i.e. the differential equation fitting method, using both the experimental and simulated hyperpolarized NMR data. The ratio fitting method appeared to fit better than the differential equation fitting method for the reverse rate constant on the mouse tumor data, with less relative errors on average, whereas the differential equation fitting method also resulted in a negative reverse rate constant for one tumor. The simulation results indicated that the accuracy of both methods depends on the width of the transport function, noise level and rate constant ratio; one method may be more accurate than the other based on the experimental/biological conditions aforementioned. We were able to categorize our tumor models into specific conditions of the computer simulation and to estimate the errors of rate quantification. We also discussed possible approaches to the development of more accurate rate quantification methods for hyperpolarized NMR. Copyright © 2013 John Wiley & Sons, Ltd.     

The prevalence of vitamin D abnormalities in South Asians with type 2 diabetes mellitus in the UK

Background: The high prevalence of both hypovitaminosis D and type 2 diabetes (T2DM) in the Asian community is well recognised, but the impact of diabetes on vitamin D status and vice versa, has not been well reported. Aims: To determine the prevalence of hypovitaminosis D in Asian patients with T2DM and its impact on glycaemic control. Methods: A cross‐sectional study was conducted in a tertiary referral centre in the UK. Two hundred and ten Asian patients aged more than 40 years were included (170 with and 40 without T2DM). Each had a standard bone profile (serum calcium, phosphate and alkaline phosphatase), serum parathyroid hormone and 25‐hydroxycholecalciferol. Results: The prevalence of low serum 25‐hydroxyvitamin D (< 50 nmol/l) was high in the group as a whole (> 80%) and more common in diabetics compared with controls (83% vs. 70%; p = 0.07). This was particularly so in men (82.5% vs. 57.9%; p = 0.02). HbA1c was higher in women with vitamin D deficiency (< 12.5 nmol/l) (8.11 ± 1.11% vs. 7.33 ± 1.32%, p = 0.046). In logistic regression analysis, T2DM was an independent predictor of hypovitaminosis D. In linear regression analysis, vitamin D deficiency was independently related to HbA1c in women with T2DM. Conclusions: Hypovitaminosis D remains a major public health issue in the Asian population and is exaggerated in patients with T2DM. The fact that vitamin D deficient women had higher HbA1c levels raises the possibility that vitamin D replacement may improve glycaemic control.     

Determination of Non-Recrystallization Temperature for Niobium Microalloyed Steel

In the present investigation, the non-recrystallization temperature (T_NR) of niobium-microalloyed steel is determined to plan rolling schedules for obtaining the desired properties of steel. The value of T_NR is based on both alloying elements and deformation parameters. In the literature, T_NR equations have been developed and utilized. However, each equation has certain limitations which constrain its applicability. This study was completed using laboratory-grade low-carbon Nb-microalloyed steels designed to meet the API X-70 specification. Nb- microalloyed steel is processed by the melting and casting process, and the composition is found by optical emission spectroscopy (OES). Multiple-hit deformation tests were carried out on a Gleeble^® 3500 system in the standard pocket-jaw configuration to determine T_NR. Cuboidal specimens (10 (L) × 20 (W) × 20 (T) mm³) were taken for compression test (multiple-hit deformation tests) in gleeble. Microstructure evolutions were carried out by using OM (optical microscopy) and SEM (scanning electron microscopy). The value of T_NR determined for 0.1 wt.% niobium bearing microalloyed steel is ~ 951 °C. Nb- microalloyed steel rolled at T_NR produce partially recrystallized grain with ferrite nucleation. Hence, to verify the TNR value, a rolling process is applied with the finishing rolling temperature near TNR (~951 °C). The microstructure is also revealed in the pancake shape, which confirms T_NR.     

Reduced toxicity of F-deficient Sendai virus vector in the mouse fetus

Current concerns over insertional mutagenesis by retroviral vectors mitigate investigations into alternative, potentially persistent gene therapy vector systems not dependent on genomic integration, such as Sendai virus vectors (SeVV). Prenatal gene therapy requires efficient gene delivery to several tissues, which may not be achievable by somatic gene transfer to the adult. Initially, to test the potential and tropism of the SeVV for gene delivery to fetal tissues, first-generation (replication- and propagation-competent) recombinant SeVV, expressing beta-galactosidase was introduced into late gestation immunocompetent mice via the amniotic and peritoneal cavities and the yolk sac vessels. At 2 days, this resulted in very high levels of expression particularly in the airway epithelium, mesothelium and vascular endothelium, respectively. However, as expected, substantial vector toxicity was observed. The efficiency of gene transfer and the level of gene expression were then examined using a second-generation SeVV. The second generation was developed to be still capable of cytoplasmic RNA replication and therefore high-level gene expression, but incapable of vector spread due to lack of the gene for viral F-protein. Vector was introduced into the fetal amniotic and peritoneal cavities, intravascularly, intramuscularly and intraspinally; at 2 days, expression was observed in the airway epithelia, peritoneal mesothelia, unidentified cells in the gut wall, locally at the site of muscle injection and in the dorsal root ganglia, respectively. Mortality was dramatically diminished compared with the first-generation vector.     

Inhibition of some rat hepatic microsomal enzymes by ethoxyquin

Administration of single intragastric doses of ethoxyquin (500 mg/kg) to rats dramatically increased the hexobarbitone sleeping time. Conversely, dietary administration of ethoxyquin (0.5% w/w) for 14 days led to a 50 per cent decrease in the hexobarbitone sleeping time. Single doses of ethoxyquin had little effect on hepatic mixed function oxidase activity. Ethoxyquin was shown to be a potent competitive inhibitor of rat hepatic microsomal biphenyl 4-hydroxylase and ethylmorphine N-demethylase in vitro (K_i = 4.3 × 10^?6 M and 6.0 × 10^?6 M respectively) and displayed a type 1 binding spectrum with cytochrome P-450 with a very high affinity (K_s = 1.06 × 10^?5 M). Ethoxyquin had no inhibitory effect on the activity of glucose-6-phosphatase in vitro.     

Neighbourhood deprivation and regional inequalities in self-reported health among Canadians: Are we equally at risk?

Individual-level data from the Canadian Community Health Survey was combined with area-level data from the 2001 Canada Census to explore the relationship between neighbourhood deprivation and regional inequalities in self-reported health (n=120,290). While neighbourhood deprivation was a significant predictor of fair/poor health in all geographic regions (OR=1.11; 95% CI: 1.08, 1.14), living on the Atlantic and Pacific coasts exacerbated the detrimental effects of neighbourhood deprivation on the perceived health of respondents (OR=1.21; 1.28). By failing to explore regional variations in risk, we could fail to identify areas where provincial policies may interact with neighbourhood factors to reinforce health inequalities amongst deprived communities.     

Radiographic evaluation of the degenerative cervical spine.

Despite some claims to the contrary, the use of plain film radiography can be an inexpensive initial means of evaluating the degenerative cervical spine if viewed in the context of the patient's clinical history and physical examination and may serve as a guide for further imaging techniques. This article presents a systematic approach for evaluating cervical spine radiographs for the spectrum of degenerative changes, followed by a brief discussion of differential diagnoses.     

Facts and figures about cancer in Bangladesh

During two decades, beginning in 1960, there was a ten-fold increase of cancer registration in Bangladesh. Lung was the most common site (17-19%) with a 14-fold increase. Cancer of the larynx constituted 14%-15% and malignant lymphoma 5%-7% of all cancers. Cancer of the esophagus was the fifth most common cancer in both sexes (3-6%), and its registration increased 11-fold. In women, cancer of the cervix was the most common lesion (23-29%) and breast cancer was second (16-18%). Registration of cervix cancer increased 39-fold, and that of breast cancer increased ten-fold. Cancer of the oral cavity constituted 26-29% of all cancers.