Retraction: Investigation on corrosion protection and mechanical performance of minerals substituted hydroxyapatite coating on HELCDEB-treated titanium using pulsed electrodeposition method.

[This retracts the article DOI: 10.1039/C4RA04484C.].

Retraction: Investigation of anticorrosive, antibacterial and in vitro biological properties of a sulphonated poly(etheretherketone)/strontium, cerium co-substituted hydroxyapatite composite coating developed on surface treated surgical grade stainless steel for orthopedic applications.

[This retracts the article DOI: 10.1039/C4RA12207K.].

Retraction: Single walled carbon nanotubes reinforced mineralized hydroxyapatite composite coatings on titanium for improved biocompatible implant applications.

[This retracts the article DOI: 10.1039/C5RA04382D.].

Retraction: Smart rose flower like bioceramic/metal oxide dual layer coating with enhanced anti-bacterial, anti-cancer, anti-corrosive and biocompatible properties for improved orthopedic applications.

[This retracts the article DOI: 10.1039/C5RA17747B.].

Development of strontium and magnesium substituted porous hydroxyapatite/poly(3,4-ethylenedioxythiophene) coating on surgical grade stainless steel and its bioactivity on osteoblast cells.

The present study deals with the successful development of bilayer coatings by electropolymerisation of poly(3,4-ethylenedioxythiophene) (PEDOT) on surgical grade stainless steel (316L SS) followed by the electrodeposition of strontium (Sr) and magnesium (Mg) substituted porous hydroxyapatite (Sr, Mg-HA). The bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM). Corrosion resistance of the obtained coatings was investigated in Ringer's solution by electrochemical techniques and the results were in good agreement with those obtained from chemical analysis, namely inductively coupled plasma atomic emission spectrometry (ICP-AES). Also, the mechanical and biological properties of the bilayer coatings were analyzed. From the obtained results it was evident that the PEDOT/Sr, Mg-HA bilayer exhibited greater adhesion strength than the Sr, Mg-HA coated 316L SS. In vitro cell adhesion test of the Sr, Mg-HA coating on PEDOT coated specimen is found to be more bioactive compared to that of the single substituted hydroxyapatite (Sr or Mg-HA) on the PEDOT coated 316L SS. Thus, the PEDOT/Sr, Mg-HA bilayer coated 316L SS can serve as a prospective implant material for biomedical applications.

Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS.

Prevalence of hyperlipidemia in diabetic infertile women.

The study was carried out to assess the lipid profile levels in diabetic infertile women as diabetes is often associated with infertility. 90 patients in the age limit 20- 40 years. One half diabetic and the other half non-diabetic presenting with a complaint of infertility were evaluated at the G. Kuppusamy Naidu Memorial Hospital, Coimbatore, Tamil Nadu, India. There was a significant increase in the triglycerides and VLDL(Very Low Density Lipid) cholesterol levels in diabetic infertile women when compared to non diabetic infertile women and hence this shows that assessment of Lipo protein levels is of much diagnostic importance and also one among the main criteria for establishing female infertility and diabetes is one of the main contributing factor which may cause fatal disorders like Cardio vascular diseases and Coronary artery diseases due to the vicious cycle caused by the combined vascular abnormalities associated with diabetes.

Cytokine gene polymorphisms and cytokine levels in pulmonary tuberculosis.

Polymorphisms in the cytokine genes are known to influence cytokine levels and may be associated with outcome of infections. We investigated the polymorphisms in the cytokine genes namely IFN-gamma (+874 and +5644), IL-2 (-330 and +160), IL-4 (VNTR), IL-6 (-174), IL-10 (-1082 and -819) and IL-12B (+1188) in 188 normal healthy subjects (NHS) and 166 pulmonary tuberculosis patients (PTB) using polymerase chain reaction-based methods. To study the influence of cytokine gene polymorphisms on cytokine levels, phytohaemagglutinin and culture filtrate antigen of Mycobacterium tuberculosis-induced cytokine levels were measured by ELISA from 72-h-old peripheral blood mononuclear cell culture supernatants. Significantly decreased frequency of TT genotype of IL-2 -330 polymorphism (p=0.024, odds ratio (OR) 0.53, 95% CI 0.31-0.92) was observed in patients compared to NHS. The genotype frequencies of other polymorphisms were not different between patients and NHS. IL-12p40 levels were significantly decreased among NHS with AA genotype of IL-12B gene polymorphism compared to NHS with AC genotype (p<0.05). Increased levels of IL-12p40 were observed among patients with CC genotype of IL-12B gene compared to patients with other genotypes (p<0.01). The present study suggests that the TT genotype of IL-2 -330 polymorphism may be associated with the protection to PTB in south India. Further, +1188 polymorphism of IL-12B gene either alone or in combination with closely linked genes may regulate IL-12p40 production and may play a major role on acquired immunity to tuberculosis.

Promoter polymorphism of IL-18 gene in pulmonary tuberculosis in South Indian population.

Interleukin-18 (IL-18) plays a vital role in both innate and acquired immunity. We analysed polymorphisms at -607(C/A) and -137(G/A) in the promoter region of IL-18 gene by allele-specific polymerase chain reaction in normal healthy subjects (n = 173) and patients with pulmonary tuberculosis (n = 165). Allele, genotype and haplotype frequencies did not differ significantly between normal healthy subjects and patients. The results suggest that the IL-18 gene promoter polymorphisms are not associated with susceptibility or resistance to pulmonary tuberculosis in south Indian population of Dravidian descent.

Influence of HLA-DR2 on perforin-positive cells in pulmonary tuberculosis.

Perforin is one of the key effector molecules of cytotoxic T cells and natural killer cells. The influence of HLA-DRB1 alleles on peripheral blood perforin-positive CD4, CD8, CD16 and CD 56 cells was studied by flow cytometry. HLA-DRB1 typing was done in normal healthy subjects (NHS: n = 156) and patients with pulmonary tuberculosis (PTB: n = 102) by polymerase chain reaction-based sequence-specific oligonucleotide hybridization method. We observed a significantly decreased percentage of total perforin-positive cells (per(+)) (P = 0.0004); CD8(+)/Per(+) (P = 0.0005); CD16(+)/Per(+) (P = 0.05) and CD 56(+)/Per(+) cells (P = 0.001) in HLA-DR2-positive PTB patients compared to non-DR2 patients. Subtyping of HLA-DR2-positive subjects at the allelic level revealed that the percentage of CD8(+)/Per(+) cells did not differ among DRB1*1501 and DRB1*1502 patients while a trend towards a decreased percentage of CD16(+)/Per(+) and CD 56(+)/Per(+) cells was noticed in DRB1*1501 patients compared to DRB1*1502 patients. The present study suggests that HLA-DR2 may be associated with down-regulation of perforin-positive cytotoxic lymphocytes and natural killer cells in pulmonary tuberculosis.

Influence of HLA-DRB1 alleles on Th1 and Th2 cytokine response to Mycobacterium tuberculosis antigens in pulmonary tuberculosis.

The influence of human leukocyte antigens (HLA) on the immune response is well established. We investigated the regulatory role of HLA-DRB1 alleles on cytokine response to live M. tuberculosis and its culture filtrate antigen (CFA) in normal healthy subjects (NHS) and pulmonary tuberculosis (PTB) patients. Th1 (IFN-gamma and IL-12p40), Th2 (IL-4 and IL-5), pro-inflammatory (IL-6 and IL-8) and anti-inflammatory (TGF-beta and IL-10) cytokines were measured by ELISA in 72-h-old peripheral blood mononuclear cell culture supernatants from 58 NHS and 48 PTB patients. HLA-DRB1 genotyping was carried out by polymerase chain reaction and dot-blot hybridization with biotinylated sequence-specific oligonucleotide probes and detection by chemiluminescence. In response to live M. tuberculosis and CFA, significantly increased levels of IL-6, IL-8 and TGF-beta and decreased IFN-gamma, IL-12p40 and IL-10 were seen in PTB patients compared to NHS. We observed a significantly increased IFN-gamma response in HLA-DRB1*03-positive NHS (p=0.03) and decreased IFN-gamma response in HLA-DRB1*15-positive patients (p=0.04) than respective allele-negative individuals. An increased level of IL-12p40 in DRB1*10 (p=0.02) and IL-10 in DRB1*12- (p=0.03) positive NHS and an increased level of IL-6 in DRB1*04- (p=0.02) positive patients were observed. The study suggests that HLA-DRB1 alleles differentially modulate the various cytokine responses to M. tuberculosis antigens, which may influence the cellular and humoral immune responses to M. tuberculosis infection in a susceptible host.

Elevated percentage of perforin positive cells in active pulmonary tuberculosis.

BACKGROUND & OBJECTIVES: Perforin is one of the major effector molecules of cytotoxic cells associated with killing of cells harbouring intracellular bacterial infection. The precise role of perforin positive cells in tuberculosis still remains controversial. The present study was done to determine the number of circulating CD4(+) and CD8(+) perforin positive cells to assess the level of cytotoxic response against Mycobacterium tuberculosis in patients with pulmonary tuberculosis. METHODS: Intracellular perforin and surface CD4 and CD8 staining of peripheral blood lymphocytes was done using specific monoclonal antibodies and enumerated using flowcytometry. RESULTS: A significantly decreased total lymphocytes (P<0.01), CD4 (P<0.001) and CD8 (P<0.01) lymphocyte counts in PTB patients was observed compared to normal healthy individuals (NHS). Intracellular perforin staining showed significantly elevated percentages of total (P<0.05) and CD8 (P<0.01) perforin positive cells in PTB patients compared to NHS. However, the absolute counts of total, CD4 and CD8 cells positive for perforin were similar in patients and NHS. INTERPRETATION & CONCLUSION: Our results suggest that during active stage of pulmonary tuberculosis there was an increased percentage of CD8 cells positive for perforin, irrespective of their absolute counts. Further, CD8(+) perforin positive cells may have increased cytolytic activity against M. tuberculosis in active pulmonary tuberculosis.