Effect of recombinant human growth hormone on serum Klotho and fibroblast growth factor 23 in children with idiopathic short stature / 中国当代儿科杂志

OBJECTIVES@#To investigate the changes in the serum levels of Klotho, fibroblast growth factor 23 (FGF23), and insulin-like growth factor-1 (IGF-1) in children with idiopathic short stature (ISS) before and after recombinant human growth hormone (rhGH) treatment, as well as the correlation of Klotho and FGF23 with the growth hormone (GH)/IGF-1 growth axis in these children.@*METHODS@#A prospective study was conducted on 33 children who were diagnosed with ISS in the Department of Pediatrics, Hebei Provincial People's Hospital, from March 10, 2021 to December 1, 2022 (ISS group). Twenty-nine healthy children, matched for age and sex, who attended the Department of Child Healthcare during the same period, were enrolled as the healthy control group. The children in the ISS group were treated with rhGH, and the serum levels of Klotho, FGF23, and IGF-1 were measured before treatment and after 3, 6, and 9 months of treatment. A correlation analysis was conducted on these indexes.@*RESULTS@#There were no significant differences in the serum levels of IGF-1, Klotho, and FGF23 between the ISS and healthy control groups (P>0.05). The serum levels of Klotho, FGF23, and IGF-1 increased significantly in the ISS group after 3, 6, and 9 months of rhGH treatment (P<0.05). In the ISS group, Klotho and FGF23 levels were positively correlated with the phosphate level before treatment (P<0.05). Before treatment and after 3, 6, and 9 months of rhGH treatment, the Klotho level was positively correlated with the IGF-1 level (P<0.05), the FGF23 level was positively correlated with the IGF-1 level (P<0.05), and the Klotho level was positively correlated with the FGF23 level (P<0.05), while Klotho and FGF23 levels were not correlated with the height standard deviation of point (P>0.05).@*CONCLUSIONS@#The rhGH treatment can upregulate the levels of Klotho, FGF23, and IGF-1 and realize the catch-up growth in children with ISS. Klotho and FGF23 may not directly promote the linear growth of children with ISS, but may have indirect effects through the pathways such as IGF-1 and phosphate metabolism. The consistent changes in Klotho, FGF23 and IGF-1 levels show that there is a synergistic relationship among them in regulating the linear growth of ISS children.

Nanopartículas de clorexidina-hexametafosfato na endodontia: síntese, caracterização, avaliação biológica e físico-química da incorporação aos cimentos endodônticos / Chlorhexidine hexametaphosphate nanoparticles in endodontics: synthesis, characterization, biological and physicochemical evaluation of incorporation to endodontic sealers

Este estudo avaliou as influências da incorporação de nanopartículas (NPs) de clorexidina-hexametafosfato em diversas propriedades dos cimentos endodônticos: AH Plus, MTA Fillapex e Pulp Canal Sealer (PCS). As NPs foram sintetizadas através de uma suspensão contendo 5 mM de hexametafosfato de sódio (HMP) e 4 mM de digluconato de clorexidina (CHX) a 20%, caracterizadas por microscopia eletrônica de varredura (MEV), espalhamento dinâmico de luz (DLS), potencial zeta, microscopia de força atômica (AFM) e espectroscopia de energia dispersiva de raios-X (EDS). Os cimentos endodônticos sofreram incorporação, em peso, de 2% e 5% das NPs. A ação antimicrobiana das amostras foi avaliada pelo teste de difusão em ágar e contato direto (DCT) frente a Enterococcus faecalis. O DCT foi conduzido em 3 tempos de armazenamento: cimentos frescos (T0), após 7 dias (T7) e após 30 dias (T30), e nos tempos de contato: 10 e 60 min. A citotoxicidade foi avaliada conforme as normas ISO 10993-12 através de extratos preparados em meio de cultura Dulbecco's modified Eagle's medium. As interações dos fibroblastos da linhagem MRC-5 com as diluições seriadas (1:1 a 1:8) dos extratos foram analisadas através do ensaio de quantificação do metabolismo mitocondrial pelo tetrazollium (MTT). O escoamento, radiopacidade, solubilidade e tempo de presa das amostras foi avaliado segundo a norma ISO 6876:2012. A solubilidade foi avaliada após 24 horas e 7 dias de imersão das amostras e o pH aferido após: 3h, 24h, 48h, 72h e 7 dias de armazenamento. Os resultados obtidos foram submetidos à análise estatística por análise de variância one-way e teste de Tukey, com nível de significância de 5%. A análise por MEV demonstrou aglomeração das NPs CHX-HMP, o diâmetro médio efetivo aferido por DLS foi de 169,39 nm e o potencial zeta foi de -10,18 mV. As NPs foram mensuradas por AFM, apresentando: 22,99 a 52,75 nm. Os elementos químicos: C, N, O, Na, P, Cl, identificados por EDS, comprovam a interação entre o digluconato de CHX e HMP. A ação antimicrobiana das NPs confirmou-se preliminarmente no teste de difusão em ágar e o DCT demonstrou o aumento da ação antimicrobiana dos cimentos endodônticos após incorporação das NPs, principalmente no MTA Fillapex, eliminando totalmente as cepas após 30 dias. A citotoxicidade dos cimentos analisados não foi potencializada pelas NPs. Houve redução do escoamento após a incorporação das NPs, no entanto sem infringir a norma ISO 6876:2012. A incorporação de NPs não alterou a radiopacidade das amostras, mas o MTA Fillapex não atingiu a radiopacidade mínima preconizada. As amostras incorporadas apresentaram redução da solubilidade após 24h de imersão, no entanto o MTA Fillapex em todas as amostras excedeu os valores preconizados pela ISO 6876:2012. Quanto ao pH, todas as amostras apresentaram decréscimo do valor com a progressão do tempo de imersão. O tempo de presa do AH Plus aumentou após a incorporação das NPs e o MTA Fillapex não atingiu a presa em nenhuma das condições testadas. Com os resultados obtidos conclui-se que a incorporação das NPs pode beneficiar o desempenho antimicrobiano dos cimentos endodônticos.(AU)

This study evaluated the influence of the incorporation of chlorhexidine hexametaphosphate NPs in various properties of the following endodontic sealers: AH Plus, MTA Fillapex and Pulp Canal Sealer (PCS). The NPs were synthesized using a suspension containing 5 mM sodium hexametaphosphate (HMP) and 4 mM 20% chlorhexidine digluconate (CHX), and characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta potential, atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS). Endodontic sealers were incorporated by weight of 2% and 5% of NPs. The antimicrobial activity of the samples was evaluated by agar diffusion test and direct contact (DCT) against E. faecalis. DCT was conducted in 3 storage times: fresh sealers (T0), after 7 days (T7) and after 30 days (T30) storage, and two contact times with E. faecalis suspension for 10 and 60 minutes. The cytotoxicity of the samples was evaluated according to ISO 10993-12 standards, through extracts prepared in Eagle modified by Dulbecco culture medium. The interactions of MRC-5 fibroblasts cell culture with the extracts serial dilutions (1: 1 to 1: 8) were analyzed by tetrazolium mitochondrial metabolism quantification assay (MTT). Samples flow, radiopacity, solubility and setting time were evaluated according to ISO 6876: 2012. Solubility was evaluated after 24 hours and 7 days of sample immersion and the pH measured after: 3h, 24h, 48h, 72h and 7 days of storage. The results were submitted to statistical analysis by one-way analysis of variance test and Tukey test, with a significance level of 5%. SEM analysis showed a tendency for CHX-HMP NPs to cluster, the effective mean diameter measured by DLS was 169,39 nm and the zeta potential: -10.18 mV. The NPs were individually measured by AFM, showing: 22.99 to 52.75 nm. The chemical elements: C, N, O, Na, P, Cl, identified by EDS, prove the interaction between CHX digluconate and HMP. The antimicrobial action of NPs was preliminarily confirmed in the agar diffusion test and the DCT demonstrated an increase in the antimicrobial action of endodontic sealers after incorporation of NPs, mainly in the MTA Fillapex, totally eliminating the strains after 30 days. There was reduction of flow after NPs incorporation, however without violating the ISO 6876: 2012 standard. The incorporation of NPs did not change the radiopacity of the samples, but MTA Fillapex did not reach the minimum radiopacity recommended. The incorporated samples showed reduced solubility after 24 hours of immersion, however the MTA Fillapex in all samples exceeded the values recommended by ISO 6876:2012.. Regarding the pH, all samples showed a decrease in the value as the immersion time progressed. AH Plus setting time increased after incorporation of NPs and MTA Fillapex did not reached setting under none of the conditions tested. With the obtained results it can be concluded that the incorporation of NPs can benefit the antimicrobial performance of endodontic sealers.(AU)

Isolation and characterization of a human cementocyte-like cell line, HCY-23

Abstract Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.

A novel application of nano eggshell/titanium dioxide composite on occluding dentine tubules: an in vitro study

Abstract To synthesize Nano eggshell-titanium-dioxide (EB@TiO2) biocomposite and to evaluate its effectiveness in occluding opened dentine tubules. EB@TiO2 was synthesized and characterized using X-ray diffraction (XRD), and Transmission Electron Microscope (TEM). Sixteen simulated bovine dentine discs were prepared and randomly assigned into four groups according to the following treatment (n = 4): Group 1: No treatment; Group 2: eggshell powder; Group 3: EB@TiO2; Group 4: Sensodyne. These were then agitated in a solution of 1g powder and 40mL water for 3hours. Thereafter, each dentine discs from the respective groups were post-treated for 5 min with 2wt% citric acid to test their acid resistant characteristics. Scanning Electron Microscope (SEM) was used to observe the effectiveness of occluded dentine pre-and post-treatment. The cytotoxicity of the synthesized EB@TiO2 was tested using NIH 3T3 assay. ANOVA was used to evaluate the mean values of the occluded area ratio and the data of MTS assay. This was followed by a multi-comparison test with Bonferroni correction (α = .05). The XRD confirmed that EB@TiO2 was successfully modified through ball-milling. The TEM revealed the presence of both spherical and irregular particle shape powders. The SEM result showed that EB@TiO2 could effectively occlude open dentine tubules. Equally, the result demonstrated that EB@TiO2 exhibited the highest acid resistant stability post-treatment. NIH 3T3 assay identified that EB@TiO2 had little effect on the NIH 3T3 cell line even at the highest concentration of 100µg/ml. This study suggests that the application of EB@TiO2 effectively occluded dentine tubules and the occlusion showed a high acid resistant stability.

Evaluation of an antibacterial orthodontic adhesive incorporated with niobium-based bioglass: an in situ study

Abstract This in situ study aimed to evaluate the antibacterial and anti-demineralization effects of an experimental orthodontic adhesive containing triazine and niobium phosphate bioglass (TAT) around brackets bonded to enamel surfaces. Sixteen volunteers were selected to use intra-oral devices with six metallic brackets bonded to enamel blocks. The experimental orthodontic adhesives were composed by 75% BisGMA and 25% TEGDMA containing 0% TAT and 20% TAT. Transbond XT adhesive (TXT) was used as a control group. Ten volunteers, mean age of 29 years, were included in the study. The six blocks of each volunteer were detached from the appliance after 7 and 14 days to evaluate mineral loss and bacterial growth including total bacteria, total Streptococci, Streptococci mutans, and Lactobacilli. Statistical analysis was performed using GLM model - univariate analysis of variance for microhardness and 2-way ANOVA for bacterial growth (p<0.05). The 20% TAT adhesive caused no difference between distances from bracket and the sound zone at 10-µm deep after 7 and 14 days. After 14 days, higher mineral loss was shown around brackets at 10- to 30-µm deep for TXT and 0% TAT adhesives compared to 20% TAT. S. mutans growth was inhibited by 20% TAT adhesive at 14 days. Adhesive with 20% TAT showed lower S. mutans and total Streptococci growth than 0% TAT and TXT adhesives. The findings of this study show that the adhesive incorporated by triazine and niobium phosphate bioglass had an anti-demineralization effect while inhibiting S. mutans and total Streptococci growth. The use of this product may inhibit mineral loss of enamel, preventing the formation of white spot lesions.

Effect of a new remineralizing biomaterial on the color of dental enamel

El objetivo de este trabajo fue describir el efecto de la composición de una sustancia remineralizante (SRM) y de la presión osmótica sobre el color dental mediante espectrofotometría. Se tomaron 104 premolares y molares humanos repartidos aleatoriamente en 2 grupos, cada uno de 52 especímenes. El grupo 1 se trató con la sustancia remineralizante SRM 55 (agente remineralizante 1) mezcla de 50 por ciento - 50 por ciento de mineral de grano fino y otro mineral de grano grueso y el grupo 2 se trató con la sustancia remineralizante SRM 91(agente remineralizante 2) contienen los mismos minerales en proporción 90 por ciento - 10 por ciento. A su vez cada grupo se dividió en 2 subgrupos, cada uno de 26 especímenes que se almacenaron así: Un subgrupo en saliva sintética con presión osmótica isotónica (PI) y el otro con presión osmótica hipotónica (PH). Se tomaron registros iniciales y finales con el espectrofotómetro Vita Easy Shade®. Con las lecturas se calcularon losparámetros de color (L*; a*; b*) y los índices de blanqueamiento (WIC; WIO; W). Los cambios de color (ΔL; ΔA; ΔB; yΔE) y los índices de blanqueamiento se compararon y se trataron todos mediante un análisis descriptivo. Las variables ΔA, ΔL, ΔB, ΔE e índice de blanqueamiento W se trataron con ANOVA y los índices WIC y WIO con un análisis de varianza no paramétrico Kruskal Wallis. Los resultados indican que la combinación A2 (SRM 91 y PI) afectó las variables ΔB y ΔE. La combinación B1 (SRM 55 Y PH) afectó las variables ΔA, ΔB y el índice de blanqueamiento WIO. Solamente SRM 91afectó la variable ΔL. La presión osmótica de la saliva y la sustancia remineralizante afectan el color del esmalte dental...

Phosphate solubilizing ability of Emericella nidulans strain V1 isolated from vermicompost.

Phosphorus is one of the key factors that regulate soil fertility. Its deficiencies in soil are largely replenished by chemical fertilizers. The present study was aimed to isolate efficient phosphate solubilizing fungal strains from Eisenia fetida vermicompost. Out of total 30 fungal strains the most efficient phosphate solubilizing one was Emericella (Aspergillus) nidulans V1 (MTCC 11044), identified by custom sequencing of β-tubulin gene and BLAST analysis. This strain solubilized 13 to 36% phosphate from four different rock phosphates. After three days of incubation of isolated culture with black Mussorie phosphate rock, the highest percentage of phosphate solubilization was 35.5±1.01 with a pH drop of 4.2±0.09. Kinetics of solubilization and acid production showed a linear relationship until day five of incubation. Interestingly, from zero to tenth day of incubation, solubility of soil phosphate increased gradually from 4.31±1.57 to 13.65±1.82 (mg kg-1) recording a maximum of 21.23±0.54 on day 45 in respect of the V1 isolate. Further, enhanced phosphorus uptake by Phaseolus plants with significant pod yield due to soil inoculation of Emericella nidulans V1 (MTCC 11044), demonstrated its prospect as an effective biofertilizer for plant growth.

Physical-chemical characteristics of whitening toothpaste and evaluation of its effects on enamel roughness

This in vitro study evaluated the physical-chemical characteristics of whitening toothpastes and their effect on bovine enamel after application of a bleaching agent (16 percent carbamide peroxide). Physical-chemical analysis was made considering mass loss by desiccation, ash content and pH of the toothpastes. Thirty bovine dental enamel fragments were prepared for roughness measurements. The samples were subjected to bleaching treatments and simulated brushing: G1. Sorriso Dentes Brancos (Conventional toothpaste), G2. Close-UP Whitening (Whitening toothpaste), and G3. Sensodyne Branqueador (Whitening toothpaste). The average roughness (Ra) was evaluated prior to the bleaching treatment and after brushing. The results revealed differences in the physical-chemical characteristics of the toothpastes (p < 0.0001). The final Ra had higher values (p < 0.05) following the procedures. The mean of the Ra did not show significant differences, considering toothpaste groups and bleaching treatment. Interaction (toothpaste and bleaching treatment) showed significant difference (p < 0.0001). The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the enamel surface, probably by the use of a bleaching agent.

Phytostabilization of mine waste: growth and physiological responses of Vigna unguiculata (L.) Walp.

Greenhouse experiments were carried out for phytoremediation of the Pb/Zn abandoned tailings (pH 3.2 and high metal content) of Rampura-Agucha Mines, Rajasthan. Vigna unguiculata (L.) Walp. (cowpea) was chosen as a test crop. On unamended tailings, the seeds of the test plant showed no germination. The tailing was amended with lime (3% on weight basis), 3% lime + NPK (diammonium phosphate at 60 kg/ha, muriate of potash at 40 kg/ ha) and 3% lime + FYM at 15 t/ha and used for experiments. Quantification of various parameters viz. shoot-root length, shoot-root dry weight, chlorophyll contents (a', 'b' and total) and peroxidase activity of test crop revealed T+ S + 3% lime + NPK to be the most suitable amelioration followed by FYM. The above treatments helped in improving the growth and productivity of the test plants by providing a favorable environment.

Amelioration of arsenic toxicity by phosphate salts in mungbean seedlings.

Sodium arsenate (Na2HAsO4.7H2O) is a potent inhibitor of mungbean seed germination and seedling growth. Germination is totally stopped at or above 50 microM Na2HAsO4.7H2O. Inhibition of seedling elongation started at a lower concentration of 5 microM As(V) and was drastically reduced at 20 microM As(V). Nutrients like salts of macroelements viz., NaH2PO4.2H2O, KH2PO4, K2SO4, MgSO4.7H2O, CaCl2.2H2O, (NH4)2SO4 NH4NO3 solutions at a concentration of 10mM and microelements viz., ZnSO4, CuSO4.5H2O, Na2MoO4.2H2O, MnCl2.4H2O, CoCl2.6H2O, FeSO4.7H2O solutions at a concentration of 1mM could help to ameliorate the toxic effects of As(V) to different degrees. Amelioration of As(V) toxicity was possible only when the mungbean seeds were pretreated with the above mentioned nutrients for 24 hr and then transferred to sodium arsenate. Simultaneous treatment of nutrients with As(V) or using nutrient solutions following As(V) treatment were of no help to reverse the toxic effects of sodium arsenate.

Ação protetora de enxaguatórios fluoretados sobre o esmalte: estudo vitro / The enamel protection fluoride ion in mouthrinses: study in vitro

O íon fluoreto administrado em humanos através de diferentes veículos, é um elemento químico que se incorpora à rede cristalina do esmalte, tornando-se importante na manutenção da saúde dental. Esta afirmação está fundamentada na possibilidade deste fármaco, particularmente, na forma de fluoreto de sódio NaF, intervir na dissolução desta estrutura biológica, reduzindo de forma satisfatória a perda de minerais e, conseqüentemente, contribuir para prevenir e controlar a cárie dental. Enquanto recurso preventivo, o flúor é uma alternativa farmacológica empregada em programas de saúde pública, dada à sua significativa eficácia e o baixo custo de aplicação. Visando subsidiar a literatura que trata da eficácia do fluoreto de sódio - NaF, veiculado através de colutórios, o presente estudo teve por objetivo determinar, in vitro, o grau de proteção do esmalte pelo íon fluoreto contido em seis enxaguatórios utilizados como recurso terapêutico de aplicação tópica, de uso freqüente e baixa concentração, após exposição experimental aos valores de pH 6.8, 6.5, 6.0m, 5.5, 5.0 e 4.5. As taxas do fosfato liberado do esmalte previamente tratado, expressas em mg/dL/20Æ, foram determinadas através de espectrofotometria, com base na técnica preconizada por Gomori e Baginski modificado (Doles Reagentes e Equipamentos para Laboratório Ltda.). Os resultados obtidos revelaram o poder protetor do fluoreto presente nos enxaguatórios avaliados. Os produtos industrializados, Refrescante Bucal Sorriso Herbal com Flúor (E1) e Plax Enxaguante Bucal com Flúor (E2), apresentaram os melhores resultados, cuja justificativa está na concentração do íon fluoreto presente, ou seja: 228 ppmF- e 227 ppmF-, respectivamente. Os demais colutórios com concentração de 226 ppmF-, revelaram semelhante poder protetor, muito embora apresentassem diferenças estatísticas significantes em relação aos produtos E1 e E2. Esta constatação deveu-se, provavelmente, à concentração mais baixa do fluoreto...

Effects of Protein Source and Energy Substrates on the In Vitro Development of Bovine Embryos in a Two-step Culture System

In this study, we examined the effects of a two-step culture system, which involves the use of different culture media for early cleavage and later stage embryos, on the in vitro development of bovine embryos. We also investigated the effect of glucose, phosphate and citrate on the in vitro early developmental period of bovine embryos in a two-step culture system. Moreover, the supplementation of different protein sources (BSA-V, BSA-FAF and FBS) during IVC did not affect the frequency of blastocyst development. Using two-step culture, embryos were cultured in protein-free media for an initial 5 days. This was then followed by the same culture media or an FBS supplemented media. The developmental rates of blastocysts in the FBS containing group were significantly higher than in the replaced with no serum containing group. Embryos cultured in mSOF supplemented with 1.5 mM glucose plus 1.2 mM phosphate were significantly inhibited. The inhibition of developmental competence by glucose plus phosphate was consistent with the existence of 0.5 mM sodium citrate. This study indicates that a two-step culture system, which applies different conditions for early cleavage embryos, i.e., serum-free media, vs. later stage embryos, with serum containing media, may be effective for in vitro production systems. In addition, the developmental competence of bovine embryos was depressed in the presence of glucose plus phosphate as compared to either alone or the absence of both. Therefore, the avoidance of this negative effect should allow more optimal conditions to be developed for in vitro production.

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

The tripeptide Hip-His-Leu was used to standardize a fluorimetric method to measure tissue angiotensin-converting enzyme (ACE) activity in rats. The fluorescence of the o-phthaldialdehyde-His-Leu adduct was compared in the presence and absence of the homogenate (25 µl) to determine whether the homogenate from different tissues interfered with the fluorimetric determination of the His-Leu product. Only homogenates from lung and renal medulla and cortex showed significantly altered fluorescence intensity. To overcome this problem, the homogenate from these tissues were diluted 10 times with assay buffer. The specificity of the assay was demonstrated by the inhibition of ACE activity with 3 µM enalaprilat (MK-422). There was a linear relationship between product formation and incubation time for up to 90 min for homogenates of renal cortex and medulla and liver, for up to 60 min for ventricles and adrenals and for up to 30 min for the aorta, lung and atrium homogenates. In addition, there was a linear relationship between product formation and the amount of protein in the homogenates within the following range: lung, 30-600 µg; renal cortex and medulla, 40-400 µg; atrium and ventricles, 20-200 µg; adrenal, 20-100 µg; aorta, 5-100 µg; liver, 5-25 µg. No peptidase activity against the His-Leu product (31 nmol), assayed in borate buffer (BB), was detected in the different homogenates except the liver homogenate, which was inhibited by 0.1 mM r-chloromercuribenzoic acid. ACE activity in BB was higher than in phosphate buffer (PB) due, at least in part, to a greater hydrolysis of the His-Leu product in PB. ACE activity of lung increased 20 percent when BB plus Triton was used. Enzyme activity was stable when the homogenates were stored at -20o or -70oC for at least 30 days. These results indicate a condition whereby ACE activity can be easily and efficiently assayed in rat tissue samples homogenized in BB using a fluorimetric method with Hip-His-Leu as a substrate.

Estudo da abrasividade de formulaçöes básicas de dentifrícios / Study of abrasivity of dentifrices basic formulations

O estudo da abrasividade de formulaçöes básicas de dentifrícios envolvendo vários tipos de espessantes e abrasivos, demonstrou uma dependência da interaçäo desses componentes, fundamentais nesse tipo de produto. As diferentes associaçöes estudadas tornaram possível a estruturaçäo de índices de abrasividade específicos a cada uma delas.

Effect of pyridoxal-5-phosphate in gel filtered blood platelets

The inhibitory effect of pyridoxal-5-phosphate [PLP] on gel filtered platelets [GFP] function has been studied. Prior addition of PLP caused inhibition of platelet aggregation and 5-HT, induced by ADP thrombin. The results showed no significant change in the formation of inositol triphosphate [IP3], due to phosphoinositides hydrolysis and of ADP induced platelets in the presence of PLP. ADP did not cause any decrease in the level of radioactivity of the phospholipids fraction nor an increase in the arachidonate metabolites from platelets treated with PLP. Prostagl and in synthetase activity was also examined and found to be not affected by PLP. The results also showed that PLP may exert its inhibitory effect by blocking the release of arachidonate but not its metabolism

Effect of dietary supplementation with pyridoxal-5-phosphate and polyunsaturated fatty acids on rat blood platelet function

Platelets were isolated from the blood of rats fed on st and ard laboratory diets and rats fed on supplements of pyridoxal-5-phosphate [PLP] and polyunsaturated fatty acids [PUFA] alone or in combination. Platelet counts and their protein and total lipid content were unaltered by the regimes. Rats fed on PUFA showed a significant increase in the linoleic acid content of the phospholipid fraction of platelets [p <0.001]. Dietary supplementation for one week with PLP or PUFA alone or in combination significantly prolonged the clotting time of freshly drawn blood, decreased the extent of ADP-induced aggregation, the release of platelet 5-hydroxytryptamine [5-HT] and the formation of thromboxane B2 [TXB2]. Furthermore, platelets isolated from rats fed on dietary supplements were more sensitive to inhibition of aggregation by PLP in vitro, and their aggregation by collagen was not similarly affected. These results pointed to a direct and specific inhibitory action of PLP on ADP-induced aggregation of blood platelets

Effect of cyclosporin A and trifluoperazine on rat liver mitochondria swelling and lipid peroxidation

The effect of cyclosporin A (CsA) or trifluoperazine (TFP) on lipid peroxidation and mitochondrial swelling was determined using liver mitochondria incubated with 30 microM Ca2+ and 250 microM t-butylhydroperoxide or 5 mM inorganic phosphate (P(i)). Lipid peroxidation was not modified by either 1 microM CsA or 40 microM TFP. These compounds presented a distinct effect on mitochondrial permeability. Under oxidative conditions, CsA only showed a transient protective effect whereas TFP completely inhibited mitochondrial swelling. Conversely, CsA was very efficient when Ca2+ and P(i) were used, a condition under which TFP was unable to prevent the swelling. These data are consistent with our previous results (M.F. Nepomuceno, D.V. Macedo and L. Pereira-da-Silva (1991). Brazilian Journal of Medical and Biological Research, 24: 833-836) showing that lipid peroxidation is one among other different components of the permeabilization process. The data suggest that lipid peroxidation is independent of swelling, occurring later than swelling, presumably when the mitochondrial reductant systems are depleted. The differential effects of CsA and TFP suggest that these compounds can be used as specific probes in the elucidation of the two distinct mechanisms responsible for mitochondrial swelling

Effect of substrate and phosphate ions on the quaternary structure symmetry of glyceraldehyde-3-phosphate dehydrogenases of mung beans and rabbit muscle.

Effects of glyceraldehyde-3-phosphate (G-3-P) and phosphate ions on thermal inactivation of glyceraldehyde-3-phosphate dehydrogenases (GPDHs) of mung beans and rabbit muscle have been studied at different pH. In the absence of any ligand, the two enzymes show a striking similarity in the pH-dependence of the kinetics of thermal inactivation. At lower pH values both the enzymes biphasic kinetics with each phase accounting for about half of the starting activity (a C2 symmetry of the homotetrameric enzyme molecule). The kinetics change to a single exponential decay at higher pH values, a D2 symmetry [Malhotra & Srinivasan (1985) Arch. Biochem. Biphys. 236, 775-781; Malhotra & Tikoo (1991) Indian, J. Biochem. Biophys. 28, 16-21]. With each enzyme, phosphate ions are found to have no effect on the kinetic pattern at lower pH, but G-3-P brings about a change from biphasic to a single exponential decay. At higher pH values, G-3-P has no effect on the single exponential decay kinetic pattern, but phosphate ions change the same to a biphasic loss of activity with each phase accounting for about half of the starting activity. It has been concluded that with both the enzymes, G-3-P and phosphate ions have higher affinity and stabilise the D2- and C2-symmetry conformation, respectively. Binding isotherms of the two substrates for these enzymes have been described based on the ligand concentration-dependence of the changes in the rate constants and kinetic pattern of thermal inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Contribuiçäo ao conhecimento das lesöes de estocagem: estudo do sistema de óxido-reduçäo glutationa dependente em eritrócitos coletados em CPDA-1 / Contribution on knowledge of storage lesions: glutathione anti-oxidant system study

A presente investigaçäo teve como objetivo o estudo do sistema de óxido-reduçäo glutationa-dependente em 34 CGV coletados em CPDA-1, nos dias 0 e 35 de estocagem. Amostras de 12 CGV foram examinadas logo após a coleta em heparina e CPDA-1, constituindo o grupo dia 0. Os valores do dia 0 foram considerados controles para 12 CGV examinados no 35§ dia de estocagem. Foram efetuados testes de reduçäo da MetaHb pelo Am (atividade G6PD) e pela CIS (atividade GSSG-Rd), dosagens de GSHt, GSSG, MDA total e eritrocitário, MetHb e Hb plasmática. Os resultados do dia 0 demonstraram preservaçäo da capacidade antioxidante da via das pentoses. Foi também observada uma lesäo incipiente da membrana, principalmente após centrifugaçäo refrigerada em GV heparinizados. No dia 35, constatou-se atividade deficiente da G6PD, deficiência de GSSG-Rd (funcional, dependente da atividade G6PD), diminuiçäo da GSHt, da GSSG, manutençäo da relaçäo [GHS] / [GSSG], refletindo uma lentidäo na capacidade antioxidante da vida das pentoses. Pelos altos níveis de Hb plasmática, ficou evidenciada uma importante lesäo da membrana, associada entretanto, a níveis pouco elevados de MDA. Estes CGC que sofreram manipulaçäo eventual e freqüênte, durante a estocagem, foram comparados a 4 unidades de CGV estocados imóveis pelo mesmo período, para GSHt e atividades G6PD e GSSG-Rd. As unidades agitadadas apresentaram o dobro das taxas de GSHt, sugerindo que a agitaçäo favorece maior síntetse e também maior reciclagem da GSH. A atividade G6PD foi menor, embora näo significante, nas unidades agitadas, provavelmente pela oxidaçäo dos seus grupamentos SH, pois um maior fluxo de oxigênio ocorre no interior da bolsa. A GSSG-Rd acompanhou funcionalmente a deficiência em G6PD. Foram estudados 10 CGV estocados imóveis por 35 dias, 6 de 150 ml e 4 de 300 ml, comparando-se amostras de GV do topo, centro, fundo da bolsa e após mistura completa do conteúdo, para alguns índices hematimétricos, GSHt e atividades G6PD e GSSG-Rd. A camada do fundo dos CGV demonstrou ser a mais compacta e menos preservada, com GV de menor VCM, maior CHCM e menores níveis de GSHt. A camada do centro foi a melhor preservada, tanto quanto a índices hematimétricos, quanto a taxas de regeneraçäo de GSHt e níveis mais homogêneos de G6PD. Nestas unidades imóveis, parece ocorrer um "choque metabólico", quando da mistura dos GV com plasma, proteases, oxigênio e espécies oxigênio reativas, pois a regeneraçäo da GSHt é semelhante...

Funçäo da glândula paratiróide em mulheres osteopênicas após a menopausa / Function of the parathyroid gland in osteopenic women after menopause

Níveis de hormônio paratiroidiano já foram descritos mais baixos, inalterados e até mais elevados em mulheres com osteoporose pós-menopausa. Alguns autores, ao infundirem EDTA e medirem o cálcio ionizado em mulheres menopausadas, observaram uma reatividade menor das glândulas paratiróides nessas mulheres. A resposta da glândula paratiróide ao estímulo com fosfato oral, em mulheres osteopênicas, nos primeiros anos da menopausa (1-6 anos) foi investigado. Doze mulheres osteopênicas (densidade óssea na coluna entre 0,900 e 0,970g/cm2), menopausadas, com idade entre 50 e 55 anos, e 11 mulheres saudáveis, controles (densidade óssea na coluna maior que 1.100g/cm2) receberam 1,5 gramas de fosfato oral, durante 15 dias. O cálcio, fósforo, fosfatase alcalina e creatinina séricas, bem como o Ca/Cr e hidroxiprolina/Cr urinários foram semelhantes nos dois grupos no início do estudo. Entretanto, o PTH aminoterminal foi estatisticamente inferior nas mulheres osteopênicas. Após ingestäo de fosfato oral, o Ca/Cr urinário nos dois grupos apresentou queda ao redor de 42-46%. O PTH aminoterminal subiu significantemente no grupo controle normal após administraçäo do fosfato, porém 75% das osteopênicas näo apresentaram qualquer alteraçäo. A resposta negativa nas mulheres ostopênicas pode ser devida a sensibilidade alterada ao PTH nessas pacientes. Os autores propöem novos estudos com sobrecarga de fosfato em todas as mulheres, nos primeiros anos da menopausa, para verificar se as "näo respondedoras" perdem mais massa óssea que as "respondedoras"