Investigation of Coatings, Corrosion and Wear Characteristics of Machined Biomaterials through Hydroxyapatite Mixed-EDM Process: A Review

Together, 316L steel, magnesium-alloy, Ni-Ti, titanium-alloy, and cobalt-alloy are commonly employed biomaterials for biomedical applications due to their excellent mechanical characteristics and resistance to corrosion, even though at times they can be incompatible with the body. This is attributed to their poor biofunction, whereby they tend to release contaminants from their attenuated surfaces. Coating of the surface is therefore required to mitigate the release of contaminants. The coating of biomaterials can be achieved through either physical or chemical deposition techniques. However, a newly developed manufacturing process, known as powder mixed-electro discharge machining (PM-EDM), is enabling these biomaterials to be concurrently machined and coated. Thermoelectrical processes allow the migration and removal of the materials from the machined surface caused by melting and chemical reactions during the machining. Hydroxyapatite powder (HAp), yielding Ca, P, and O, is widely used to form biocompatible coatings. The HAp added-EDM process has been reported to significantly improve the coating properties, corrosion, and wear resistance, and biofunctions of biomaterials. This article extensively explores the current development of bio-coatings and the wear and corrosion characteristics of biomaterials through the HAp mixed-EDM process, including the importance of these for biomaterial performance. This review presents a comparative analysis of machined surface properties using the existing deposition methods and the EDM technique employing HAp. The dominance of the process factors over the performance is discussed thoroughly. This study also discusses challenges and areas for future research

18F-FDG PET/CT for diagnosing infectious complications in patients with severe neutropenia after intensive chemotherapy for haematological malignancy or stem cell transplantation

Item does not contain fulltextPURPOSE: Between 30 and 50% of febrile neutropenic episodes are accounted for by infection. C-reactive protein (CRP) is a nonspecific parameter for infection and inflammation but might be employed as a trigger for diagnosis. The aim of the study was to evaluate whether (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT can be used to detect inflammatory foci in neutropenic patients with elevated CRP and whether it helps to direct treatment. METHODS: Twenty-eight consecutive patients with neutropenia as a result of intensive chemotherapy for haematological malignancies or myeloablative therapy for haematopoietic stem cell transplantation were prospectively included. (18)F-FDG PET/CT was added to the regular diagnostic workup once the CRP level rose above 50 mg/l. RESULTS: Pathological FDG uptake was found in 26 of 28 cases despite peripheral neutrophil counts less than 0.1 x 10(-9)/l in 26 patients: in the digestive tract in 18 cases, around the tract of the central venous catheter (CVC) in 9 and in the lungs in 7 cases. FDG uptake in the CVC tract was associated with coagulase-negative staphylococcal bacteraemia (p < 0.001) and deep venous thrombosis (p = 0.002). The number of patients having Streptococcus mitis bacteraemia appeared to be higher in patients with grade 3 oesophageal FDG uptake (p = 0.08). Pulmonary FDG uptake was associated with the presence of invasive fungal disease (p = 0.04). CONCLUSION: (18)F-FDG PET/CT scanning during chemotherapy-induced febrile neutropenia and increased CRP is able to detect localized foci of infection and inflammation despite the absence of circulating neutrophils. Besides its potential role in detecting CVC-related infection during febrile neutropenia, the high negative predictive value of (18)F-FDG PET/CT is important for avoiding unnecessary diagnostic tests and therapy.1 januari 201

Leukocytospermia and sperm preparation - a flow cytometric study

Reprod Biol Endocrinol. 2009 Nov 19;7:12

The OSU1/QUA2/TSD2-Encoded Putative Methyltransferase Is a Critical Modulator of Carbon and Nitrogen Nutrient Balance Response in Arabidopsis

The balance between carbon (C) and nitrogen (N) nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar1 mutants (osu1-1, osu1-2) in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N), the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90) and an Asn synthetase isoform (ASN1) are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants

Potential biological role of poly (ADP-ribose) polymerase (PARP) in male gametes

Maintaining the integrity of sperm DNA is vital to reproduction and male fertility. Sperm contain a number of molecules and pathways for the repair of base excision, base mismatches and DNA strand breaks. The presence of Poly (ADP-ribose) polymerase (PARP), a DNA repair enzyme, and its homologues has recently been shown in male germ cells, specifically during stage VII of spermatogenesis. High PARP expression has been reported in mature spermatozoa and in proven fertile men. Whenever there are strand breaks in sperm DNA due to oxidative stress, chromatin remodeling or cell death, PARP is activated. However, the cleavage of PARP by caspase-3 inactivates it and inhibits PARP's DNA-repairing abilities. Therefore, cleaved PARP (cPARP) may be considered a marker of apoptosis. The presence of higher levels of cPARP in sperm of infertile men adds a new proof for the correlation between apoptosis and male infertility. This review describes the possible biological significance of PARP in mammalian cells with the focus on male reproduction. The review elaborates on the role played by PARP during spermatogenesis, sperm maturation in ejaculated spermatozoa and the potential role of PARP as new marker of sperm damage. PARP could provide new strategies to preserve fertility in cancer patients subjected to genotoxic stresses and may be a key to better male reproductive health

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8–13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05–6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50–75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life. Funding Pfizer, Amgen, Merck Sharp & Dohme, Sanofi–Aventis, Daiichi Sankyo, and Regeneron

Effects of L-Carnitine on inducible nitric oxide synthase, insulin like growth factor-1 gene expression and insulin receptor substrate-1 in kidney tissues of insulin resistant rats induced by high fructose feeding

Metabolism of high dietary fructose induces insulin resistance and metabolic adaptation including changes in gene expression. The present study was designed to elucidate the effects of L-Carnitine (CA) on the renal alterations as well as gene expression such as inducible Nitric Oxide Synthase (iNOS). Insulin-like Growth Factor-1(IGF-1), insulin receptor substrate-1 (IRS-1) in kidney tissues of rats fed on high fructose diet. 24 male Wister rats of body weight 120-160 g were divided into 3 groups of 8 rats each . Group 1 received control diet, while group 2 and 3, rats received high fructose diet (60 g/100 g diet). Group 3, after 2 weeks of fructose feeding animals were treated with CAR (300 mg/kg body weight/day i.p). At the end of the experimental period (30 days), serum levels of glucose, insulin, Triacylglycerol (TG) and cholesterol were determined. Renal contents of cholesterol, triacylglycerol, Malondialdehyde (MDA) and nitric oxide products were determined . Gene expressions of iNOS, IGF-1 as well as IRS-1 were also assayed in kidney tissues of the experimental rats feed on high fructose diet. Rats fed on high fructose diet showed disturbance in insulin action and formed an animal model of insulin resistance. Fructose fed rats showed increase in renal gene expression of iNOS and decrease in both IGF-1 mRNA and IRS-1 receptor compared to control rats. The administration of CA to rat model of insulin resistance, mitigated the adverse effects of fructose load. Thus the observed abnormalities in gene expression associated with fructose feeding were brought to near-normal levels as compared with untreated rats. Conclusion: L-carnitine normalized the serum and renal lipid alterations as well as gene expression (iNOS, IGF-1) and IRS-1 in this nutritional experimental model.Key words : Insulin resistance, L-carnitine, inducible nitric oxide synthase (iNOS), growth factor-1 gene expression, insulin receptor substrate-1 (IRS-1

Biochemical Alterations Of Amino Acids, Neurotransmitters And Hepatic Functions After Thermal Injury In Rats

Thermal injury in human and animals models may be complicated by dysfunction to organs distant from the original burn wound. The physiopathological events following thermal injury are not limited to the surface effects of heat but are also related to an acute inflammatory reaction with increased muscle protein breakdown. The aim of the present study was to investigate the biochemical alterations of some amino acids, brain neurotransmitters and hepatic functions during postburn stage in scalded rats. Male Wistar rats inflicted by 30% total body surface area (TBSA) were employed as the model and were randomly divided into 5 groups; normal sham control, 1,3,5 & 7 days postburn groups, with 8 rats in each groups. Serum levels of IL-6 was estimated by ELISA method. Serum concentrations of amino acids were determined by amino acid analyzer. Levels of homocystein and glutathione were estimated by HPLC method. At the sametime, brain neurotransmitters, serum ALT, AST, ALP and &#947;-GT levels were also assayed. There was a decreasing tendency in varying degrees in serum concentrations of most amino acids at each time points. Serum homocysteine level in all scalding groups were markedly lower than that in sham control group at all postburn time points. GSH concentration was significantly decreased at D5 and D7, however, the concentration of GSSG was increased at D1, D3 and D7 and GSH/GSSG ratio was decreased at D1, D3, D5 and D7 postburn when compared to the sham control. There was increasing tendency in brain concentration of norepinephrine and dopamine, while the level of brain serotonin showed a pronounced decrease after one day following burn injury and 3 &5 days postburn its levels increased significantly when compared to sham group. At the seventh day following burn, serotonin level was found to be replenished back to that of the sham control group. The serum levels of ALT, AST, ALP and &#947;-GT were increased obviously at all postburn time points. In conclusion, we found that, There were significant changes in serum contents of amino acids and brain neurotransmitters during postburn stage in scalded rats, which might be related to the early excessive release of inflammatory mediators, enhanced degradation of skeletal muscle and impairment of hepatic function. Keywords: burns, IL-6, neurotransmitters, liver, amino acids, glutathione, homocysteine Egyptian Journal of Biochemistry and Molecular Biology Vol. 26 (2) 2008: pp. 13-2