HAC Group Research Articles

Impact of high-altitude acclimatization and de-acclimatization on the intestinal microbiota of rats in a natural high-altitude environment.

Intestinal microorganisms play an important role in the health of both humans and animals, with their composition being influenced by changes in the host's environment. We evaluated the longitudinal changes in the fecal microbial community of rats at different altitudes across various time points. Rats were airlifted to high altitude (3,650 m) and acclimatized for 42 days (HAC), before being by airlifted back to low altitude (500 m) and de-acclimatized for 28 days (HADA); meanwhile, the control group included rats living at low altitude (500 m; LA). We investigated changes in the gut microbiota at 12 time points during high-altitude acclimatization and de-acclimatization, employing 16S rRNA gene sequencing technology alongside physiological indices, such as weight and daily autonomous activity time. A significant increase in the Chao1 index was observed on day 14 in the HAC and HADA groups compared to that in the LA group, indicating clear differences in species richness. Moreover, the principal coordinate analysis revealed that the bacterial community structures of HAC and HADA differed from those in LA. Long-term high-altitude acclimatization and de- acclimatization resulted in the reduced abundance of the probiotic Lactobacillus. Altitude and age significantly influenced intestinal microbiota composition, with changes in ambient oxygen content and atmospheric partial pressure being considered key causal factors of altitude-dependent alterations in microbiota composition. High-altitude may be linked to an increase in anaerobic bacterial abundance and a decrease in non-anaerobic bacterial abundance. In this study, the hypobaric hypoxic conditions at high-altitude increased the abundance of anaerobes, while reducing the abundance of probiotics; these changes in bacterial community structure may, ultimately, affect host health. Overall, gaining a comprehensive understanding of the intestinal microbiota alterations during high-altitude acclimatization and de-acclimatization is essential for the development of effective prevention and treatment strategies to better protect the health of individuals traveling between high- and low-altitude areas.

Sequence-based epitope mapping of high pathogenicity avian influenza H5 clade 2.3.4.4b in Latin America.

High Pathogenicity Avian Influenza (HPAI) poses a significant threat to public and animal health. Clade 2.3.4.4b recently emerged from the Eastern hemisphere and disseminated globally, reaching the Latin American (LATAM) region in late 2022 for the first time. HPAI in LATAM has resulted in massive mortalities and culling of poultry and wild birds, causing infection in mammals and humans. Despite its meaningful impact in the region, only occasional evidence about the genetic and epitope characteristics of the introduced HPAI is reported. Hence, this study seeks to phylogenetically characterize the molecular features and the source of HPAI in LATAM by evaluating potential antigenic variations. For such a purpose, we analyzed 302 whole genome sequences. All Latin American viruses are descendants of the 2.3.4.4b clade of the European H5N1 subtype. According to genomic constellations deriving from European and American reassortments, the identification of three major subtypes and eight sub-genotypes was achievable. Based on the variation of antigenic motifs at the HA protein in LATAM, we detected three potential antigenic variants, indicating the HA-C group as the dominant variant. This study decidedly contributes to unraveling the origin of the 2.3.4.4b clade in LATAM, its geographic dissemination, and evolutionary dynamics within Latin American countries. These findings offer useful information for public health interventions and surveillance initiatives planned to prevent and manage the transmission of avian influenza viruses.

A Bioinspired Astrocyte-Derived Coating Promotes the In Vitro Proliferation of Human Neural Stem Cells While Maintaining Their Stemness.

The repair of neuronal tissue is a challenging process due to the limited proliferative capacity of neurons. Neural stem cells (NSCs) can aid in the regeneration process of neural tissue due to their high proliferation potential and capacity to differentiate into neurons. The therapeutic potential of these cells can only be achieved if sufficient cells are obtained without losing their differentiation potential. Toward this end, an astrocyte-derived coating (HAc) was evaluated as a promising substrate to promote the proliferation of NSCs. Mass spectroscopy and scanning electron microscopy were used to characterize the HAc. The proliferation rate and the expression of stemness and differentiation markers in NSCs cultured on the HAc were evaluated and compared to the responses of these cells to commonly used coating materials including Poly-L-Ornithine (PLO), and a Human Induced Pluripotent Stem Cell (HiPSC)-based coating. The use of the HAc promotes the in vitro cell growth of NSCs. The expression of the stemness markers Sox2 and Nestin, and the differentiation marker DCX in the HAc group was akin to the expression of these markers in the controls. In summary, HAc supported the proliferation of NSCs while maintaining their stemness and neural differentiation potential.

Remineralization Potential of a Combination of Chitosan with Nanohydroxyapatite and a Self-assembling Peptide with Nanohydroxyapatite: An In Vitro Study.

This study explores the demineralizing potential of the combination of chitosan with nanohydroxyapatite (n-HA) and self-assembling peptides with n-HA. A total of 66 first premolar teeth of similar dimensions extracted for orthodontic purposes were collected for this study. These were then demineralized and randomly divided into the following three groups (n = 22): (i) Control group, (ii) n-HA + Chitosan (HAC), and (iii) self-assembling peptide + n-HA (SP-HA). The samples in each group were brushed every 24 hours with the respective agent. The specimens were stored in Fusayama Meyer's artificial saliva at room temperature and the solution was replenished daily. Mineral content (Ca, P) and surface morphology of the specimens was analyzed, using scanning electron microscopy and energy dispersion X-ray spectroscopy (SEM-EDAX), before demineralization, at 15 days of remineralization and 30 days of remineralization. A two-way analysis of variance (ANOVA) test followed by Tukey's honest significant difference (HSD) post hoc analysis was used to compare the mean elemental composition of the different groups (p < 0.05). There was no significant difference in the calcium (Ca) and phosphate (P) weight percentage between the different groups at the baseline and after demineralization. The Ca and P weight percentages of all three groups after remineralization for 15 and 30 days showed no significant difference from the baseline or after demineralization. The surface morphology after 15 days of remineralization therapy showed decreased surface porosity and increased mineral deposition in the HAC group than the HP-SA group. Surface morphology after 30 days of remineralization showed a more homogenous and smoother surface in the HAC group than the HP-SA group. From the results of this study, it can be concluded that the combination of chitosan with n-HA and self-assembling peptides with n-HA can be considered effective demineralizing agents. Considering the non-invasive nature of remineralization therapy understanding the effectiveness of different agents is of utmost importance. The demineralizing properties of chitosan, n-HA and self-assembling peptides make their combinations ideal for studying their effectiveness in treating white spot lesions.

Fracture Resistance of Custom Lithium Disilicate Implant Restorations with Two Fabrication Techniques and Two Designs.

To compare the fracture resistance of a press-on ceramic custom implant restoration with pressed and cemented restorations. Thirty-two (32) lithium disilicate (IPS e.max Press) custom hybrid abutment restorations were fabricated. The restorations were divided into two groups (n = 16) according to the construction technique: the commercial control group (C) and the press-on group (P). For the control group, lithium disilicate restorations were pressed and cemented on titanium bases. For the press-on group, lithium disilicate pressable ceramic (IPS e.max Press) was pressed on the titanium bases with injection molding. Each group was further divided according to the restoration design, either screw- or cement-retained, into two subgroups of eight specimens each. Specimens of C group were divided into screw-retained (cemented hybrid abutment crown, CHAC) or cement-retained (cemented hybrid abutment, CHA). Specimens of the P group were also divided into screw-retained (pressed hybrid abutment crown, PHAC) and cement-retained (pressed hybrid abutment, PHA). The specimens were subjected to static loading until failure with a universal testing machine. Two-way analysis of variance (ANOVA) was used to assess the effect of different techniques and designs on the fracture resistance of the samples (P < .05), followed by one-way ANOVA and Tukey honest significant difference (HSD) test (α = .05). C group showed higher mean fracture resistance (812.443 ± 129.14 N) than P group (596.71 ± 108.83 N), and the difference was statistically significant (P < .05). Regarding restoration design, HA groups showed higher mean fracture resistance (742.621 ± 153.82 N) than HAC (666.53 ± 163.07 N) groups with no statistically significant difference. CHA showed the highest mean fracture resistance (817.65 ± 161.76 N), while PHAC showed the lowest mean fracture resistance values (525.83 ± 47.29 N). The commercial cemented lithium disilicate restorations showed higher fracture resistance than the press-on restorations, although both showed a maximum load capacity that was greater than physiologic incisal force in the anterior region, and both hybrid abutments and hybrid abutment crowns were equally efficient in withstanding occlusal loading forces.

Effects of ammonia on growth performance, lipid metabolism and cecal microbial community of rabbits.

This study was designed to investigate the effect of ammonia on growth performance, lipid metabolism and intestinal flora of rabbits. A total of 150 female IRA rabbits (35-days-old) were randomly divided into three groups including 0 ppm (CG), 10 ppm (LAC) and 30 ppm ammonia (HAC) groups for a period of 28 days. The average daily weight gain (ADG) of rabbits was significantly reduced in LAC (-17.11%; p < 0.001) and HAC groups (-17.46%; p < 0.001) as compared with the CG. Serum concentration of high density lipoprotein (HDL) and glucose (Glu) were increased in LAC (+80.95%; +45.99; p < 0.05) and HAC groups (+219.05%; +45.89; p < 0.001), while apolipoprotein A1 (apoA1) was decreased in LAC (-58.49%; p < 0.001) and HAC groups (-36.92%; p < 0.001). The structural integrity of cecum was damaged, and the thickness of mucosa and serosa were significantly decreased in LAC and HAC. The acetate, butyrate and propionate level of cecal chyme were reduced in HAC group (-21.67%; -19.82%; -30.81%; p < 0.05). Microbial diversity and burden of Firmicutes were significantly decreased, while that of pathogenic bacteria, such as Bacteroidetes, Clostridium and Proteobacteria were increased in ammonia treated groups. Spearman’s correlation confirmed that burden of Ruminococcaceae_NK4A214_group showed significantly negative correlation with acetic acid (r = -0.67; p < 0.001) while Barnesiellaceae_unclassified showed significantly positive correlation with propionic acid (r = 0.50; p < 0.001). In conclusion, ammonia treatment was responsible for an imbalance of intestinal flora, which affected lipid metabolism and damaged intestinal barrier of rabbits, resulting in low growth performance due to lipid metabolism dysfunction.

Biochemical and haematological parameters in dogs with Cushing’s syndrome

The exposure of the body to stress, regardless of whether it comes from physical, chemical or emotional stimuli from the environment, causes an inadequate adaptation of the organisms which can contribute to the development of various diseases. Abnormally high blood concentrations of cortisol, known as stress hormone, lead to the development of a hormonal disorder called hyperadrenocorticism or Cushing’s syndrome. In the majority of cases, Cushing’s syndrome is diagnosed when symptoms are apparent, and screening endocrinological test confirms the existence either of increased cortisol production or decreased sensitivity of the hypothalamic-pituitary-adrenal axis to negative glucocorticoid feedback. In our research, we examined a total of 23 male and 7 female dogs that were suspected to have Cushing’s syndrome, based on history and clinical signs. A total of 15 male and 5 female dogs were positive for Cushing’s syndrome (HAC group), whereas the remaining dogs were used to form non-HAC group. Using the apparatus IDEXX “Vet Test 8008”, the following biochemical parameters were determined: glucose, urea, creatinine, phosphorus, calcium, total protein, albumin, globulin, alanine aminotransferase, alkaline phosphatase, bilirubin, cholesterol, and amylase. Regarding haematological parameters, the following parameters were investigated: erythrocytes, leukocytes, platelets, erythrocyte indices (MCV, MCH, MCHC, RDW), white blood cell count, haemoglobin and haematocrit, using “Laser cite vet lab Station” (IDEXX). No significant differences in haematological and biochemical blood parameters were noticed between the HAC and the non-HAC group of dogs. However, dogs suffering from Cushing’s syndrome had a higher value in the number of erythrocytes compared to the control group. The finding that has to be payed attention to is the difference in platelet count between the control group of dogs and dogs suffering from Cushing’s syndrome.

Acupuncture at ST36 exerts neuroprotective effects via inhibition of reactive astrogliosis in infantile rats with hydrocephalus

BackgroundAcupuncture has been associated with improved cerebral circulation, analgesia, neuromodulatory function and neurogenesis. In particular, acupuncture at ST36 has been widely used in several central nervous system (CNS) disorders, including...

Promoted Chondrogenesis of Cocultured Chondrocytes and Mesenchymal Stem Cells under Hypoxia Using In-situ Forming Degradable Hydrogel Scaffolds.

We investigated the effects of different oxygen tension (21% and 2.5% O2) on the chondrogenesis of different cell systems cultured in pH-degradable PVA hydrogels, including human articular chondrocytes (hACs), human mesenchymal stem cells (hMSCs), and their cocultures with a hAC/hMSC ratio of 20/80. These hydrogels were prepared with vinyl ether acrylate-functionalized PVA (PVA-VEA) and thiolated PVA-VEA (PVA-VEA-SH) via Michael-type addition reaction. The rheology tests determined the gelation of the hydrogels was controlled within 2-7 min, dependent on the polymer concentrations. The different cell systems were cultured in the hydrogel scaffolds for 5 weeks, and the safranin O and GAG assay showed that hypoxia (2.5% O2) greatly promoted the cartilage matrix production with an order of hAC > hAC/hMSC > hMSC. The real time quantitative PCR (RT-PCR) revealed that the hMSC group exhibited the highest hypertrophic marker gene expression (COL10A1, ALPL, MMP13) as well as the dedifferentiated marker gene expression (COL1A1) under normoxia conditions (21% O2), while these expressions were greatly inhibited by coculturing with a 20% amount of hACs and significantly further repressed under hypoxia conditions, which was comparative to the sole hAC group. The enzyme-linked immunosorbent assay (ELISA) also showed that coculture of hMSC/hAC greatly reduced the catabolic gene expression of MMP1 and MMP3 compared with the hMSC group. It is obvious that the hypoxia conditions promoted the chondrogenesis of hMSC by adding a small amount of hACs, and also effectively inhibited their hypotrophy. We are convinced that coculture of hAC/hMSC using in situ forming hydrogel scaffolds is a promising approach to producing cell source for cartilage engineering without the huge needs of primary chondrocyte harvest and expansion.

Quantitative electroencephalography analysis in university students with hazardous alcohol consumption, but not alcohol dependence.

Hazardous alcohol consumption is a pattern of consumption that leads to a higher risk of harmful consequences either for the user or for others. This pattern of alcohol consumption has been linked to risky behaviors, accidents, and injuries. Individuals with hazardous alcohol consumption do not necessarily present alcohol dependence; thus, a study of particular neurophysiological correlates of this alcohol consumption pattern needs to be carried out in nondependent individuals. Here, we carried out a quantitative electroencephalography analysis in health sciences university students with hazardous alcohol consumption, but not alcohol dependence (HAC), and control participants without hazardous alcohol consumption or alcohol dependence (NHAC). We analyzed Absolute Power (AP), Relative Power (RP), and Mean Frequency (MF) for beta and theta frequency bands under both eyes closed and eyes open conditions. We found that participants in the HAC group presented higher beta AP at centroparietal region, as well as lower beta MF at frontal and centroparietal regions in the eyes closed condition. Interestingly, participants did not present any change in theta activity (AP, RP, or MF), whereas previous reports indicate an increase in theta AP in alcohol-dependent individuals. Our results partially resemble those found in alcohol-dependent individuals, although are not completely identical, suggesting a possible difference in the underlying neuronal mechanism behind alcohol dependence and hazardous alcohol consumption. Similarities could be explained considering that both hazardous alcohol consumption and alcohol dependence are manifestations of behavioral disinhibition.

MicroRNAs expression in CD4 T cells from HTLV-1 individuals

HAM/TSP is an inflammatory manifestation of central nervous system caused by HTLV-1 and the mechanism of HAM/TSP development is no well elucidated. Currently, a promising approach on the physiopathogenesis of viral infections has been the evaluation of microRNAs (miRNAs) role. There are few data involving CD4+ T cells miRNA expression in HTLV-1 infection as well as in HAM/TSP establishment. To identify miRNAs differentially expressed in CD4+ T cells among non-infected individuals (CT), asymptomatic (HAC) and HAM/TSP patients we applied quantitative real time PCR. The analysis of miRNA expression profile in these cells showed 56 and 10 miRNAs upregulated 1.5 times in HAM/TSP and HAC groups, respectively. miR-125b-1-1 was upregulated in HAC group and miR-146a in HAM/TSP. Target prediction by in silico analysis showed that IFNG was a potentially miR-125b-1-1 target and IRAK1 and TRAF6 were miR-146a targets. IFNG expression was 1.3 higher in HAC than CT group and 1.8 higher in HAM/TSP than CT group. It was observed that TRAF6 expression was 15.7 and 1.5 times higher in HAM/TSP and HAC groups, respectively. There was no difference of IRAK1 expression among the three groups. Overexpression assays of miR-125b-1-1 altered IFNG expression and overexpression of miR-146a altered IRAK1 gene and protein expression. The results revealed that miRNAs could modulate genes and proteins during HTLV-1 infection. miR-125b and IFNG gene correlation suggests that miR-125b seems to contribute to HAM/TSP development. Besides, interaction between miR-146a and IRAK1/TRAF6 suggests that miR-146a seems to contribute to HTLV-1 establishment in CD4+ T cells.

Genes related to antiviral activity are differentially expressed in CD4+ T cell in HAM/TSP patients

CD4+ T cells play a central role in HTLV-1 infection. We investigated the global gene expression profile of circulating CD4+ T cells in HTLV-1-infected individuals. The microarray platform was performed using 12 individual RNA samples: healthy control (CT, n=4), asymptomatic HTLV-1 carrier (HAC, n=4) and HAM/TSP group (n=4). Proviral load (PVL), Tax expression and the percentage of CD4+Foxp3+ cells were analyzed. Hierarchical clustering analysis showed that CT and HTLV-infected groups clustered separately. We identified 25 differentially expressed genes in common between CT vs. HAM/TSP and HAM/TSP vs. HAC analyses and we observed their participation in granzyme A (GZMA) signaling pathways. GZMA, GZMB and PRF1 were validated by qRT-PCR. GZMA and PRF1 gene expression was significantly increased in HAM/TSP group compared to CT and HAC groups. No difference was observed in gene expression level of GZMB. Regulatory T cells (Treg) cells have cytolytic capacity and perforin/granzyme pathways are required for this activity. Foxp3 gene expression was evaluated and it was significantly increased in HAM/TSP group compared to CT and HAC groups. GZMA, GZMB, and PRF1 genes were positively correlated to Foxp3 gene expression. PRF1 and Foxp3 genes were positively correlated with Tax expression and PVL. The percentage of CD4+Foxp3+ cells revealed a significant increase in HAC and HAM/TSP groups compared to CT. Our results suggest that Treg cells may use the perforin/granzyme pathway as a system to suppress the immune cells and may contribute to immunodeficiency, which is observed in HTLV-1 infection.

Effects of Corn Naturally Contaminated with Aflatoxins on Performance, Calcium and Phosphorus Metabolism, and Bone Mineralization of Broiler Chicks

The objective of this study was to investigate the effects of corn naturally contaminated with low levels of aflatoxins (AF) on performance, calcium (Ca) and phosphorus (P) metabolism, and bone mineralization in broilers. Four hundred and fifty 1-d-old male broiler chicks were randomly allotted to control (no AF), and the diet with the corn contaminated with AF as a substitute for 50% or 100% of the corn in control (HAC or AAC). The broilers in HAC and AAC were administered with 6.5-8.0 and 13.0-16.0 μg AF/kg BW per day respectively in overall period (1-42 d). Ten birds per treatment were selected at d 43 to explore the apparent digestibility of Ca and P using all excreta collection method after 2 days adaptation. The AAC diet reduced (P<0.05) the performance of birds in overall period, whereas the HAC diet temporarily decreased (P<0.05) the performance of birds in starter phase (1-21 d). The corn contaminated with AF had no effect (P>0.24) on the apparent digestibility of Ca and P. The increasing AF intake content linearly increased (P<0.001) serum parathyroid hormone (PTH) level, and decreased (P<0.05) serum 1,25-dihydroxychocalciferol and P concentrations on d 42. On d 21, the AAC diet reduced (P<0.05) tibia breaking strength (TBS) when compared to control or HAC group, however, it did not affect (P>0.10) the percentages of ash, Ca and P in tibia. On d 42, the increasing AF intake level linearly decreased (P<0.05) TBS, and the percentages of Ca and P in tibia. These results indicated that the low level of AF intake had negative effects on the P metabolism and bone mineralization of broilers at exposure of 42 days, which might relate to the changes in vitamin D and PTH metabolism.

Association of interleukin - 18 gene polymorphism with susceptibility or protective effect to HTLV-1 infection

Methods The promoter region polymorphic sites (-137C/G and -607A/C) were evaluated by polymerase chain reaction sequence specific primers (PCR-SSP) analysis using peripheral blood DNA obtained from HAC (54), HAM (44) and healthy control (150) individuals. Proviral load of infected patients (HAC and HAM) was determined by real-time PCR. Results The -607CC genotype was less frequent for HAC group (p=0.0501; OR=0.4890; CI=0.2480 to 0.9643), and infected patients (p=0.0232; OR=0.5207; CI=0.3033 to 0.8937) compared to healthy controls. The -607AC genotype was more frequent for HAC group (p=0.0387; OR=1.991; CI=1.043 to 3.801), and infected patients (p=0.0376; OR=1.757; CI=1.047 to 2.948) compared to healthy controls. No significant difference was observed for allelic and genotypic frequencies of the -137C/G among deferments groups. No significant difference was observed for allelic and genotypic frequencies of the -137C/G and -607A/C polymorphisms when correlated with proviral load. Conclusion The -607CC (high producer of IL-18) genotype exhibited protective effect against the infection, whereas the -607AC genotype conferred susceptibility to HTLV-1 infection.

HLA-G 14-bp Insertion/Deletion Polymorphism Is a Risk Factor for HTLV-1 Infection

About 95% of HTLV-1 infected patients remain asymptomatic throughout life, and the risk factors associated with the development of related diseases, such as HAM/TSP and ATL, are not fully understood. The human leukocyte antigen-G molecule (HLA-G), a nonclassical HLA class I molecule encoded by MHC, is expressed in several pathological conditions, including viral infection, and is related to immunosuppressive effects that allow the virus-infected cells to escape the antiviral defense of the host. The 14-bp insertion/deletion polymorphism of exon 8 HLA-G gene influences the stability of the transcripts and could be related to HTLV-1-infected cell protection and to the increase of proviral load. The present study analyzed by conventional PCR the 14-bp insertion/deletion polymorphism of exon 8 HLA-G gene in 150 unrelated healthy subjects, 82 HTLV-1 infected patients with symptoms (33 ATL and 49 HAM), and 56 asymptomatic HTLV-1 infected patients (HAC). In addition, the proviral load was determined by quantitative real-time PCR in all infected groups and correlated with 14-bp insertion/deletion genotypes. The heterozygote genotype frequencies were significantly higher in HAM, in the symptomatic group, and in infected patients compared to control (p < 0.05). The proviral load was higher in the symptomatic group than the HAC group (p < 0.0005). The comparison of proviral load and genotypes showed that -14-bp/-14-bp genotype had a higher proviral load than +14-bp/-14-bp and +14-bp/+14-bp genotypes. Although HLA-G 14-bp polymorphism does not appear to be associated with HTLV-1 related disease development, it could be a genetic risk factor for susceptibility to infection.

Effect of Hydroxyapatite on Bone Integration in a Rabbit Tibial Defect Model

BackgroundThe aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study.MethodsTen rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting.ResultsThe HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p < 0.05). On comparing the change of bone mineral density the bone ingrowth surface area among the 4 groups, there were no statistically significant differences among the groups found for any period (p > 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged.ConclusionsWe concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology.

The comparative study on the biocompatibility of four kinds of scaffolds

Objective To explore the biocompatibility of NHAC,INHAC,HAC as well as CHA by co-culturing with BMSCs in vitro. Methods BMSCs (a density of 2×10~5 cells/ml) were separately co-cultured with four scaffolds in vitro. The cell viability was assayed by MTT assay, the activity of ALP was measured, and the morphological changes were observed under the scanning electron microscopy (SEM). Results The activities of ALP in CHA,NHAC,INHAC,HAC,and control groups were 2. 207±0. 079,2.225±0.059,2.194±0.088,0.981±0.210, and 2.231±0.087, respectively. The BMSCs co-cultured with NHAC, INHAC and CHA could preserve normal proliferating speed, and activity of ALP showed no significant difference as compared with control group (P>0.05), but there was significant dif-ferent between HAC and control groups (P<0.01). SEM revealed the co-cultured BMSCs could prolifer-ate and grow well on the surface and in the holes of the NHAC, INHAC and CHA except for HAC. Conclu-sion NHAC,INHAC and CHA exert good biocompatibility and can be used as biomaterial in bone tissue engineering. Key words: Tissue engineering; Biocompatibility; Nano; BMSC

Resistance exercise plus to aerobic activities is associated with better lipids' profile among healthy individuals: the ATTICA study

The influence of different types of exercise on risk factors for cardiovascular diseases has rarely been investigated. The aim of the present work was to evaluate the effect of adding resistance exercise to aerobic activities on lipid-lipoprotein profile, in a representative sample of men and women from the province of Attica, Greece. We randomly enrolled 1514 and 1528 healthy men and women, respectively, stratified by city, age and gender distribution. Participants were classified as inactive (INA), sufficiently active (SA) and highly active for either aerobic activities (HAA) alone or a combination of aerobic plus resistance exercise (HAC). The main outcome measures are lipid-lipoprotein profile [total, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein-A1, apolipoprotein-B] and anthropometric indices. From those participating in aerobic activities, 480 (31.7%) men and 502 (32.9%) women were classified as SA, 100 men (6.6%) and 93 women (6.1%) as HAA and 90 men (5.9%) and 49 women (3.2%) as HAC. After various adjustments were made, men from the HAC group had an average of 23% lower plasma triacylglycerol concentration (P = 0.04) and 10% lower LDL-cholesterol (P = 0.01) when compared with the HAA group. Moreover, women from the HAC group had 13% lower LDL-cholesterol when compared with HAA group (P = 0.051). These data suggest that combining aerobic and resistance-type activities may confer a better effect on lipoprotein profile in healthy individuals than aerobic activities alone.

Resorption Mechanism of Hydroxyapatite and β-Tricalcium Phosphate Coating Layer

Beta-tricalcium phosphate(β-TCP) coating layer is known to be resorbed much faster than hydroxyapatite(HA), however, there has been no report to explain the exact reason of these results. Eighty titanium discs, coated with HA(n=40) or β-TCP(n=40) by dip and spin coating method, were divided into 2 subgroups respectively; Dissolution(D, n=20) and osteoclast culture(C, n=20). The coated discs in D group were immersed in the cell culture media for 5 days, whereas, in C group, osteoclasts were seeded on the specimens and cultured for 5 days. After simple dissolution test, β-TCP coating layer showed much more cracks and denudation as compared to HA. In osteoclast culture group, mean area fraction of resorption pits in HA-C group was 11.62%, which was significantly higher than that of 0.73% in β-TCP-C group(p=0.001). In conclusion, the resorption mechanisms of HA and β-TCP coating layers were different each other in vitro study. The coated β-TCP was degraded mainly by dissolution and separation from implant, on the other hand, the HA coating layer was resorbed by osteoclastic activity.

Urine cortisol:creatinine ratio as a screening test for hyperadrenocorticism in dogs

Summary A urine cortisol:creatinine (c:c) ratio, determined from a free-catch morning sample, was evaluated in each of 83 dogs as a screening test for hyperadrenocorticism. The dogs evaluated were allotted to 3 groups, including 20 healthy dogs, 40 dogs with confirmed hyperadrenocorticism (hac), and 23 dogs with polyuria and polydipsia not attributable to hac (polyuria/polydipsia group; pu/pd). Overlap in the urine c:c ratios (mean ± sem), comparing results from the healthy dogs (5.7 × 10-6 ± 0.9) with those from the hac dogs (337.7 × 10-6 ± 72.0) was not found. However, 11 (64%) of the 18 values from the pu/pd dogs (42.6 × 10-6 ± 9.4) were above the lowest ratio in the hac group and 50% of the hac group had a urine c:c ratio below the highest value in the pu/pd group. When the mean urine c:c ratio (± 2 sd) for the group of healthy dogs was used as a reference range, 100% of the hac dogs and 18 (77%) of 23 dogs in the pu/pd group had abnormal urine c:c ratios. The sensitivity of the urine c:c ratio to discriminate dogs with hac was 100%. The specificity of the urine c:c ratio was 22% and its diagnostic accuracy was 76%. On the basis of our findings, a urine c:c ratio within the reference range provides strong evidence to rule out hac. However, abnormal urine c:c ratios are obtained from dogs with clinical diseases other than hac. Therefore, measurement of a urine c:c ratio should not be used as the sole screening test to confirm a diagnosis of hac.