Microarray illustrates enhanced mechanistic action towards osteogenesis for magnesium aluminate spinel ceramic-based polyphasic composite scaffold with mesenchymal stem cells and bone morphogenetic protein 2

Spinel (magnesium aluminate MgAl2 O4 ) ceramic-based polyphasic composite scaffold has been recently reported for craniofacial bone tissue engineering. Improving the osteogenic effects of such composite scaffolds with bone morphogenetic proteins (BMP2) is an intensely researched area. This study investigated the gene interactions of this scaffold with BMP2 and mesenchymal stem cells (MSCs). Human bone marrow MSCs were cultured in 3 groups: Group 1-Control (BMSCs), Group 2-BMSC with BMP2, and Group 3-BMSC with scaffold and BMP2. After RNA isolation, gene expression analysis was done by microarray. Differentially expressed genes (DEGs) (-1.0 > fold changes>1 and p value <.05) were studied for their function and gene ontologies using Database for Annotation, Visualization and Integrated Discovery (DAVID). They were further studied by protein-protein interaction network analysis using STRING and MCODE Cytoscape plugin database. Group 3 showed up regulation of 3222 genes against 2158 of Group 2. Group 3 had five annotation clusters with enrichment scores from 2.08 to 3.93. Group 2 had only one cluster. Group 3 showed activation of all major osteogenic pathways: TGF, BMP2, WNT, SMAD, and Notch gene signaling with effects of calcium and magnesium released from the scaffold. Downstream effect of all these caused significant activation of RUNX2, the key transcriptional regulator of osteogenesis in Group 3. STRING and MCODE Cytoscape plugin demonstrated the interactions. The enhanced MSC differentiation for osteogenesis with the addition of BMP2 to the polyphasic composite scaffold proposed promising clinical applications for bone tissue engineering.

P6342Subcutaneous delivery of NPA7, first-in-class novel bispecific designer peptide: enhances cardiorenal function and suppresses renin and aldosterone in vivo and in vitro

Introduction

The rapid increase of patients of heart failure (HF) is a major health burden worldwide. Most importantly is the need to develop innovative new drugs for treatment of HF, such as sacubitril/valsartan which in part functions by enhancing the natriuretic peptides (NPs). We engineered NPA7 as a novel 30 amino acid bispecific designer peptide which activates the particulate guanylyl cyclase A receptor (pGC-A)/cGMP and for which the NPs both ANP and BNP are ligands and the Mas-receptor (MasR)/cAMP pathways for Angiotensin 1–7 (Ang1–7) is the endogenous ligand. We previously reported that acute intravenous (IV) administration of NPA7 shows cardiorenal protective and renin-aldosterone suppressing actions that go beyond the native peptides, BNP or Ang 1–7, which may have therapeutic potential for HF.

Purpose

To support the clinical development of NPA7 as a potential therapy in HF which promotes NP and MasR pathways, we investigated the actions and stability of subcutaneous (SQ) administration of NPA7 in normal canines. We also defined NPA7's peptide stability and metabolites in canine plasma.

Methods

Plasma and urinary cGMP, cardiorenal and renin-aldosterone responses to SQ injection (10μg/kg) were determined over 4 hours in normal canines (n=5) in vivo. Ex vivo, we established stability of NPA7 and key metabolites in canine serum using liquid chromatography-mass spectrometry (LC-MS). Data are expressed as mean ± SEM. * P<0.05 vs. BL.

Results

In vivo, SQ NPA7 resulted in a sustained increase at 2 hours in plasma (BL: 10±3; 120 min: 30±6* pmol/ml) and urinary (BL: 1033±198; 120 min: 5792±857* pmol/min) cGMP, GFR (BL: 29±6; 120 min: 70±12* ml/min) and sodium excretion (BL: 18±10; 120 min: 144±33* ueq/min). We observed a gradual reduction in BP at 60 min (BL: 109±4; 60 min: 99±7* mmHg) with a sustained decrease in PCWP at 4 hours (BL: 5±0.9; 240 min: 3.1±0.6* mmHg). SQ NPA7 also suppressed plasma renin and aldosterone up to 3 hours after SQ injection. LC-MS revealed that NPA7 was highly stable with both the pGC-A and MasR activating moieties intact ex vivo in canine serum with a disappearance time of 2 hours. We also identified 2 major NPA7 metabolites NPA71–27 and NPA71–28.

Conclusions

SQ NPA7 possesses cGMP activating, cardiac unloading, diuretic, natriuretic, and renin-aldosterone suppressing actions in normal canines. NPA7 is also highly stable in serum. These studies support SQ administration as an effective delivery strategy for NPA7, a first-in-class innovative bispecific dual pGC-A/MasR activator now in preclinical development for HF.

Comparative evaluation of the tensile bond strength of two silicone based denture liners with denture base resins

BACKGROUND

To evaluate and compare tensile bond strength of two silicone based liners with heat cure and heat cure high impact denture base resin at baseline and after storage in artificial saliva for 30 and 60 days.

METHOD

Heat cure conventional and high impact acrylic blocks (120 blocks each) prepared with final test specimen of two blocks of each resin with a liner. The baseline samples and those tested after 30 and 60 days interval stored in artificial saliva in thermal incubator, all were pulled apart in UTM at 20 mm/min. The tensile bond strength and mode of failure (adhesive/cohesive) were assessed. Mean, SD determined and analysis using one way ANOVA and paired 't' test.

RESULTS

The highest mean tensile bond strength (1.028 MPa) and the least i.e. 0.289 MPa was observed with Permaflex silicone liner against heat cure PMMA after storage in artificial saliva at 37 ± 1 °C.

CONCLUSION

The study rejected the null hypothesis because storage time in artificial saliva affected the bond strength of the resilient liners examined. The results revealed a statistically significant difference (p < 0.05) of artificial saliva storage on the bond strength of both the liners. After storage in artificial saliva for 30 days and 60 days at 37 ± 1 °C, all the specimens showed a significant reduction in the tensile bond strength.

Does Hollowing of Complete Denture Enhance Retention? - A Pilot Study

INTRODUCTION

Prosthetic rehabilitation is an extremely challenging task in extreme resorption cases of the maxillary denture-bearing area. Reducing the weight of a maxillary obturator has been seen as beneficial. But whether reducing the weight of conventional complete denture also increases retention or not, is still very dubious. The aim of this pilot study was to determine the effect of maxillary denture weight on denture retention and stability.

MATERIALS AND METHODS

For this study, a total of 10 patients were considered for the pilot study (06 female and 04 male) with an average age of 70 y. Each patient was provided with two sets of maxillary complete dentures, one hollow labeled as A and one conventional maxillary denture labeled as B.

RESULTS

It was shown that mean values for retention using MKIS for retention for hollow dentures (A) was 7.8 and for conventional dentures (B) it was 8.2 and the stability for maxillary dentures was more with conventional dentures (B) than hollow maxillary dentures (A) and it was significant as p-value was 0.015 (p<.1).

CONCLUSION

The denture retention and stability, chewing and comfort values of conventional dentures and hollow dentures were slightly better for conventional dentures.

Transparent magnesium aluminate spinel: a prospective biomaterial for esthetic orthodontic brackets

Adult orthodontics is recently gaining popularity due to its importance in esthetics, oral and general health. However, none of the currently available alumina or zirconia based ceramic orthodontic brackets meet the esthetic demands of adult patients. Inherent hexagonal lattice structure and associated birefringence limits the visible light transmission in polycrystalline alumina and make them appear white and non transparent. Hence focus of the present study was to assess the feasibility of using magnesium aluminate (MgAl2O4) spinel; a member of the transparent ceramic family for esthetic orthodontic brackets. Transparent spinel specimens were developed from commercially available white spinel powder through colloidal shaping followed by pressureless sintering and hot isostatic pressing at optimum conditions of temperature and pressure. Samples were characterized for chemical composition, phases, density, hardness, flexural strength, fracture toughness and optical transmission. Biocompatibility was evaluated with in-vitro cell line experiments for cytotoxicity, apoptosis and genotoxicity. Results showed that transparent spinel samples had requisite physico-chemical, mechanical, optical and excellent biocompatibility for fabricating orthodontic brackets. Transparent spinel developed through this method demonstrated its possibility as a prospective biomaterial for developing esthetic orthodontic brackets.

Laser ionization mass spectrometry in oral squamous cell carcinoma

Biomarker research in oral squamous cell carcinoma (OSCC) aims for screening/early diagnosis and in predicting its recurrence, metastasis and overall prognosis. This article reviews the current molecular perspectives and diagnosis of oral cancer with proteomics using matrix-assisted laser desorption ionization (MALDI) and surface-enhanced laser desorption ionization (SELDI) mass spectrometry (MS). This method shows higher sensitivity, accuracy, reproducibility and ability to handle complex tissues and biological fluid samples. However, the data interpretation tools of contemporary mass spectrometry still warrant further improvement. Based on the data available with laser-based mass spectrometry, biomarkers of OSCC are classified as (i) diagnosis and prognosis, (ii) secretory, (iii) recurrence and metastasis, and (iv) drug targets. Majority of these biomarkers are involved in cell homeostasis and are either physiologic responders or enzymes. Therefore, proteins directly related to tumorigenesis have more diagnostic value. Salivary secretory markers are another group that offers a favourable and easy strategy for non-invasive screening and early diagnosis in oral cancer. Key molecular inter-related pathways in oral carcinogenesis are also intensely researched with software analysis to facilitate targeted drug therapeutics. The review suggested the need for incorporating 'multiple MS or tandem approaches' and focusing on a 'group of biomarkers' instead of single protein entities, for making early diagnosis and treatment for oral cancer a reality.

Type 2 diabetes express highway, where is the 'U' turn?

The 'U' turn in Type 2 Diabetes Express Highway probably lies in lifestyle modifications--going back to traditional lifestyle with use of modern technology to achieve happiness. There is a difference between technology for comfort and technology for happiness.

An ergonomic study of chronic musculoskeletal pain in schoolchildren

OBJECTIVE

Schoolchildren developing chronic musculoskeletal pain from carrying heavy backpacks (hereafter referred to as "pain") is a worldwide issue. The present study of two cohorts, consisting of 248 Indian and 103 American schoolchildren aged 9.0 to 20.6 years, using a semi-objective pain criteria, sought to answer the questions: Can pain be correlated with Body Mass Index (BMI), Weight Carried, Strength, Mood or Body Fat? What are the similarities and differences between the Indian and American schoolchildren in the above context?

METHODS

After obtaining parental consent, the schoolchildren completed a questionnaire. Then, they were weighed with and without carry-on items and their height as recorded. Isometric arm and shoulder strengths were measured using the Jackson Strength Tester. Using a Skinfold Caliper, skinfold thicknesses at the right triceps and calf was measured. Using the Borg Pain Scale the students assessed the pain experienced from their own backpacks, rated the acute pain experienced while carrying a standard 10 kg. or 7 kg. backpack.

RESULT

Half the schoolchildren reported pain located primarily in the shoulders and back (where most students carry their backpacks). Pain did not correlate with study variables (p > 0.05), and the student moods were mostly happy or neutral. Americans are five times as stressed or sad than the Indians, and the average weight carried decreased as the grade increased. The mean of the age, height, arm and shoulder strengths, and BMI for the 5th to 8th grade schoolchildren (younger groups) and the 9th to 12th grade schoolchildren (older groups), in India, was lower than their American counterparts (p < 0.05). In contrast, the weight carried to school by the Indian children was higher (p < 0.05). The mean pain level perceived by both the younger and older groups in both countries, was not statistically different (p > 0.05).

CONCLUSION

Musculoskeletal pain in schoolchildren due to carrying heavy backpacks is a significant problem. There are some similarities, but a number of differences between the Indian and American schoolchildren. Implementing the Pain Prevention Screening is expected to minimize pain, if not lead to a pain-free child.

Diabetes mellitus in Dombivli--an urban population study

OBJECTIVE

The present study was undertaken with the following aims and objectives. a) To determine the prevalence of diabetes. b) To compare the prevalence of newly diagnosed diabetic subjects, diagnosed by the ADA and WHO criteria. c) To determine to what extent prevalence rates are affected by gender, age and body mass index.

METHODS

The study population consisted of 520 subjects aged 20 years and above selected by random sampling. Blood glucose both fasting and post glucose (75 gms) two hours sample were analyzed. Baseline clinical data like height, weight and blood pressure were recorded. Known cases of diabetes were excluded from the study.

RESULTS

The prevalence of diabetes (fasting blood glucose) as per WHO criteria was 4.61% while it was 7.5% as per ADA criteria. The prevalence according to the two hour glucose reading was 6.15%. The mean glucose level increase with age. With increasing BMI the percentage of diabetic subjects also increases. The prevalence of impaired glucose tolerance (IGT) was 8.6% in subjects below 50 years and 13.4% in subjects older than 50 years. IGT values also increase with increasing age and BMI. 1.3% of subjects had normal fasting glucose level (< 126 mgm%) but high post glucose levels (> 200 mgm%).

CONCLUSIONS

The prevalence of diabetes and IGT is higher as compared to earlier studies. The mean blood glucose and IGT increase with increasing age and BMI. Several subjects had normal fasting blood glucose but increased two hour blood glucose level indicating that fasting glucose alone should not be used to diagnose DM. Urbanization and life style of residents of Dombivli contribute to the high prevalence.

Sickle cell syndromes in and around Bardoli

The study comprised of 2 groups. In group I sickling test was done in students studying in a school which mainly caters to the educational needs of the backward community. Out of 130 students examined 24 were found to be sicklers. The distribution of this cases among various castes/tribes were as follows--Choudharys (Cd)-13, Gamits (Gt)-4, Dhodhia Patels (DP)-4, Koknis (K)-2 and Koli Patel (KP)-1. In group II, patients admitted in the hospital between Jan '81 to June '82 were studied. The prevalence of sickle cell syndrome was 1.74%. The most common mode of presentation were limb pains and weakness. Hemoglobin values ranged from 3.0 gram% to 12 gms%. 35 cases of HbSS, 149 cases of HbAS and 1 case of Sickle Beta thalassemia were seen. The distribution of the cases amongst the various tribes and castes were as follows-Cd-93, Gt-56, DP-23, KP-7, K-4 and Rathods (R)-2. No cases were found in Anavil Brahmins or Patidar Patels. Clinical and pathological observations included palpable splenomegaly in 54 cases, splenic abscess in 1 case, isothenuria in large number of patients, microscopic hematuria in 6 cases and frank hematuria in 1 case. Osteomyelitis and cholecystitis were seen in one case each.