Mixing properties of bi-disperse ellipsoid assemblies: mean-field behaviour in a granular matter experiment.

The structure and spatial statistical properties of amorphous ellipsoid assemblies have profound scientific and industrial significance in many systems, from cell assays to granular materials. This paper uses a fundamental theoretical relationship for mixture distributions to explain the observations of an extensive X-ray computed tomography study of granular ellipsoidal packings. We study a size-bi-disperse mixture of two types of ellipsoids of revolutions that have the same aspect ratio of α ≈ 0.57 and differ in size, by about 10% in linear dimension, and compare these to mono-disperse systems of ellipsoids with the same aspect ratio. Jammed configurations with a range of packing densities are achieved by employing different tapping protocols. We numerically interrogate the final packing configurations by analyses of the local packing fraction distributions calculated from the Voronoi diagrams. Our main finding is that the bi-disperse ellipsoidal packings studied here can be interpreted as a mixture of two uncorrelated mono-disperse packings, insensitive to the compaction protocol. Our results are consolidated by showing that the local packing fraction shows no correlation beyond their first shell of neighbours in the binary mixtures. We propose a model of uncorrelated binary mixture distribution that describes the observed experimental data with high accuracy. This analysis framework will enable future studies to test whether the observed mean-field behaviour is specific to the particular granular system or the specific parameter values studied here or if it is observed more broadly in other bi-disperse non-spherical particle systems.

Determination of the cryoprotective effect of n-methylacetamide in rabbit semen.

BACKGROUND: Amides are low molecular weight cryoprotectants. N-methylacetamide (MA) is one of the cryoprotectant agents in this group. OBJECTIVE: To investigate the cryoprotective effect of MA in rabbit semen. MATERIALS AND METHODS: For this purpose, six ejaculates from six New Zealand rabbits were collected and pooled using an artificial vagina. Pooled semen was divided into four equal parts and diluted with TCG+ egg yolk. CPA was added to form the following groups: Control with 6% DMSO; Group 1 with 1% MA; Group 2 with 2% MA; and Group 3 with 3% MA. After the addition of CPA, the semen eqilibration procedure was started. Sperm were then drawn into 0.25 mL straws, frozen by automatic semen freezing and stored in a liquid nitrogen container. Pipettes were thawed after 24 h and analyses were performed. RESULTS: Total, progressive and rapid motility values of the Control group were higher than those of the MA groups (p<0.05). However, there was no statistical difference between the Control and Group 2 in terms of these parameters. While there was no statistical difference between the groups in terms of acrosome damage and mitochondrial membrane potential, the best results were observed in Control, Group 2, Group 1 and Group 3, respectively. When we compared all groups, no difference was found in terms of MDA, CAT and GSH-Px. There was a statistical difference between Group 3 and the Control in terms of GSH level (p<0.05). CONCLUSION: DMSO appeared to be more useful for the cryopreservation of rabbit semen compared to MA. Doi.org/10.54680/fr23610110812.

Three-dimensional bone grafting in dental implantology using autogenous bone ring transplant: Clinical outcomes of a one-stage technique.

BACKGROUND: An insufficient bone volume at the maxillary anterior region often restricts dental implant treatment and commonly leads to poor aesthetic outcomes. The defective site requires bone grafting as an initial surgical intervention before dental implant placement. In dental implantology, reconstructing osseous defects using autologous block bone grafts, biomaterials, or a combination of both is a routine surgical procedure. This study aims to evaluate the efficacy of autogenous, symphyseal, bone ring block grafts after the augmentation of defective sockets and clinical application of grafts in the maxillary anterior region with immediate insertion of a dental implant in a single surgical procedure. MATERIALS AND METHODS: The study included eight patients (five females and three males) with 12 defective sockets. The technique included removing the bone from the chin region for transplant, fitting the three-dimensional bone rings in the prepared sockets of the maxillary anterior region, and screwing the dental implants through the rings. Patients underwent postoperative clinical examinations every day during the first week and then every month for 6 months. RESULTS: In two cases, the wound dehisced but healed by secondary intervention during the follow-up period. In one case, the ring graft sequestrated because of infection in postoperative month 2, the osseous defect was reconstructed with biomaterials. The remaining cases healed with no infection, and no other case failed during the first year. CONCLUSION: This technique showed promising and advantageous results, and thus, could be an alternative treatment to other autogenous graft techniques, particularly for defective sockets.

Effect of gestational diabetes mellitus on testis and pancreatic tissues of male offspring.

The purpose of this study was to determine the effect of gestational diabetes mellitus (GDM) on some reproductive characteristics, testicular and pancreatic oxidative status and pancreatic endocrine receptor densities of male offspring at post-pubertal stage. A total of 36 1-day-old Wistar Albino male offspring including 12 pups of nontreated mothers (control group), 14 pups of 40 mg/kg STZ-injected mothers (STZ-40 group) and 10 pups of 60 mg/kg STZ-injected mothers (STZ-60 group) were used. The offspring were euthanised on post-natal day 60, their blood, reproductive organs and pancreatic tissues were obtained and examined. When compared with the control group, there was a significant decrease in body and absolute reproductive organ weights, serum testosterone level, testicular and pancreatic catalase activities, pancreatic glutathione level, epididymal sperm concentration of both STZ-40 and STZ-60 groups as well as in testicular glutathione level of only STZ-60 group. Significant increases were determined in testicular and pancreatic malondialdehyde level and glutathione peroxidase activity in both groups and in fasting serum glucose of only STZ-60 group in comparison with the control group. Although some histopathological damages were observed in testes of both STZ-40 and STZ-60 groups, there were no detectable differences between the groups in density of insulin, glucagon and somatostatin receptors in pancreas. In conclusion, GDM has negative effects on reproductive efficiency and testicular-pancreatic tissue oxidant/antioxidant balance of male offspring at post-pubertal stage.

Effect of etodolac hydrazone, a new compound synthesised from etodolac, on spermatozoon quality, testicular lipid peroxidation, apoptosis and spermatozoon DNA integrity.

The aim of this study was to investigate the effect of etodolac hydrazone (EH), a new compound synthesised from etodolac, on spermatozoon quality, testicular lipid peroxidation, apoptosis and spermatozoon DNA integrity in rats. Group 1 (n = 8) received 1 ml dimethyl sulfoxide (DMSO) daily (Control); group 2 (n = 8) was treated with 5 mg kg(-1)  day(-1) EH, dissolved in 1 ml DMSO (EH-5); and group 3 (n = 8) was treated with 10 mg kg(-1)  day(-1) EH, dissolved in 1 ml DMSO (EH-10). All administrations were performed by gavage and maintained for 8 weeks. Both doses of EH administration caused significant decreases in absolute and relative weights of testis, whole epididymis, right cauda epididymis, and spermatozoon motility, spermatozoon count in comparison with the control group. Only 10 mg kg(-1)  day(-1) EH administration caused significant decreases in absolute and relative weights of seminal vesicles and serum testosterone level, and significant increases in testicular lipid peroxidation level, and numbers of TUNEL+ apoptotic germ cells and spermatozoa with damaged DNA along with some histopathological damages when compared to the control group. However, body and ventral prostate weight, and testicular antioxidant markers (glutathione, glutathione-peroxidase and catalase), were unaffected significantly by both doses of EH administration. In conclusion, two different doses of EH, in particular its high dose, damage to testicular spermatogenic cells and spermatozoon DNA and, it decreases spermatozoon motility, count and testosterone level in healthy rats.

Quercetin attenuates carbon tetrachloride-induced testicular damage in rats.

This study was conducted to investigate the effect of quercetin on carbon tetrachloride (CCl4 )-induced sperm damages, testicular apoptosis and oxidative stress in male rats. Group 1 served as control, group 2 was treated with only quercetin, group 3 was treated with only CCl4 and group 4 received CCl4 + quercetin. All administrations were performed by gavage and maintained for 10 weeks. CCl4 administration caused significant decreases in absolute and relative reproductive organ weights, sperm motility, concentration and testicular glutathione peroxidase (GSH-Px) and catalase (CAT) activities, and significant increases in lipid peroxidation (LPO) level, abnormal sperm rate and testicular apoptotic cell index, along with some histopathological damages when compared to the control group. However, administration of CCl4 together with quercetin provided statistically significant improvements in LPO level, abnormal sperm rate, the degree of histopathological lesions and testicular apoptotic cell index when compared to only CCl4 group. In addition, improvements observed in absolute and relative weights of reproductive organs, sperm motility and concentration, and testicular GSH-Px and CAT activities in group 4 were statistically insignificant when compared to only CCl4 group. In conclusion, quercetin has antiperoxidative effect, and its oral administration attenuates the CCl4 -induced some damages in male reproductive organs and cells by decreasing the LPO.

Effectiveness of cinnamon (Cinnamomum zeylanicum) bark oil in the prevention of carbon tetrachloride-induced damages on the male reproductive system.

In this study, it was aimed to investigate the likelihood of detrimental effects of carbon tetrachloride (CCl4 ) on male reproductive system through oxidative stress mechanism and also protective effects of cinnamon bark oil (CBO). For this purpose, 28 healthy male Wistar rats were divided into four groups, seven rats in each. Group 1 received only olive oil daily; group 2 was treated with 100 mg kg(-1) CBO daily; group 3 was treated with only 0.25 ml kg(-1) CCl4 weekly; and group 4 received weekly CCl4 + daily CBO. All administrations were made by intragastric catheter and maintained for 10 weeks. Body and reproductive organ weights, sperm characteristics, testicular oxidative stress markers and testicular apoptosis were examined. CCl4 administration caused significant decreases in body and reproductive organ weights, testicular catalase (CAT) activity, sperm motility and concentration, and significant increases in lipid peroxidation (LPO) level, abnormal sperm rate and apoptotic index along with some histopathological damages compared with the control group. However, significant improvements were observed in absolute weights of testis and epididymis, all sperm quality parameters, LPO level, apoptotic index and testicular histopathological structure following the administration of CCl4 together with CBO when compared to group given CCl4 only. The findings of this study clearly suggest that CBO has protective effect against damages in male reproductive organs and cells induced by CCl4 .

Effects of cinnamon (Cinnamomum zeylanicum) bark oil on testicular antioxidant values, apoptotic germ cell and sperm quality.

Cinnamon and its contents have multifactorial properties such as antioxidant, anti-inflammatory and antidiabetic. Male infertility is one of the major health problems in life. The aim of this study was to investigate the effects of long-term cinnamon bark oil (CBO) ingestion on testicular antioxidant values, apoptotic germ cell and sperm quality of adult rats. Twelve male healthy Wistar rats were divided into two groups, each group containing six rats. While olive oil was given to control group, 100 mg kg(-1)  CBO was administered to the other group by gavage daily for 10 weeks. Body and reproductive organ weights, sperm characteristics, testicular lipid peroxidation and antioxidant enzyme activities, and testicular apoptosis via terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) method were examined. A significant decrease in malondialdehyde level and marked increases in reduced glutathione level, glutathione peroxidase and catalase activities were observed in rats treated with CBO compared with the control group. CBO consumption provided a significant increase in weights of testes and epididymides, epididymal sperm concentration, sperm motility and diameter of seminiferous tubules when compared with the control group. However, CBO consumption tended to decrease the abnormal sperm rate and apoptotic germ cell count, but it did not reach statistical significance. It is concluded that CBO has improvement effect on testicular oxidant-antioxidant balance and sperm quality, and its consumption may be useful for asthenozoospermic men.

The effect of luteolin on spermatological parameters, apoptosis, oxidative stress rate in freezing rabbit semen.

The aim of the present study was to determine the effects of Luteolin (LUT) on semen quality, oxidative stress, apoptosis, acrosomal integrity, mitochondrial membrane potential and dead sperm ratio in rabbits. Ejaculates from six New Zealand rabbits were collected, evaluated and pooled. The pooling was divided into five groups as control (no additive) LUT 25 µM, LUT 50 µM, LUT 100 µM and LUT 200 µM and LUT added. It was then filled into a falcon tube with Tris-based extender at a final concentration of approximately 35 x 106 spermatozoa. Diluated rabbit semen samples were drawn into frozen and thawed. Frozen semen straws were thawed at 37°C in 30 seconds. According to our findings, no statistical difference was found between all doses of luteolin and the control group in the CASA (computer assisted sperm analysis) analysis performed at 4°C. However, total motility, progressive motility and rapid sperm percentage were found to be higher in the frozen and thawed rabbit semen at a dose of LUT 50 µM compared to the other groups (p⟨0.05). While amplitude of lateral head displacement (ALH) and beat cross-frequency (BCF) values were found at the lowest dose of LUT 200 µM, a statistically significant difference was observed between the other groups. When the flow cytometry results were examined, no statistical difference was found between the rate of dead sperm, acrosomal integrity, mitochondrial membrane potential and apoptosis rate. Morever, the H2 O2 percentage was found to be lower in all experimental groups compared to the control group (p⟨0.001). In conclusion, the addition of LUT in long-term storage of rabbit semen provided a protective effect for spermatozoa with its antioxidative properties against damage caused by cryopreservation.

Rose oil inhalation protects against formaldehyde-induced testicular damage in rats.

In this experimental study, harmful effects of formaldehyde (FA) inhalation on sperm concentration, sperm quality, serum testosterone levels and the rat testes were investigated. In addition, the possible protective effects of rose oil against to these harmful effects were evaluated. For this purpose, 21 albino-Wistar rats were used. The rats in Group I were used as control group. When the rats of Group II were exposed FA (10 ppm/1 h) for 35 days, the rats of Group III inhalated rose oil (1 ml/1 h) after FA. The epididymal tissues were taken for sperm analysing and the testes were removed for histological examination. In addition, testosterone levels were determined from the blood samples. Although the testosterone levels, the epididymal sperm concentration, and the progressive sperm motility significantly decreased, the abnormal sperm rate significantly increased in the Group II when compared to Group I. In the Group III, these damages were seen less. When the rats in the Group II compared with the control group, there were serious histological damages. In the Group III, it was determined that the histological changes were less than group II. It can be expressed that serious damages occurred via formaldehyde exposure in male reproductive system and that the rose oil had protective effects against these damages.

The chiral structure of porous chitin within the wing-scales of Callophrys rubi.

The structure of the porous three-dimensional reticulated pattern in the wing scales of the butterfly Callophrys rubi (the Green Hairstreak) is explored in detail, via scanning and transmission electron microscopy. A full 3D tomographic reconstruction of a section of this material reveals that the predominantly chitin material is assembled in the wing scale to form a structure whose geometry bears a remarkable correspondence to the srs net, well-known in solid state chemistry and soft materials science. The porous solid is bounded to an excellent approximation by a parallel surface to the Gyroid, a three-periodic minimal surface with cubic crystallographic symmetry I4132, as foreshadowed by Stavenga and Michielson. The scale of the structure is commensurate with the wavelength of visible light, with an edge of the conventional cubic unit cell of the parallel-Gyroid of approximately 310 nm. The genesis of this structure is discussed, and we suggest it affords a remarkable example of templating of a chiral material via soft matter, analogous to the formation of mesoporous silica via surfactant assemblies in solution. In the butterfly, the templating is achieved by the lipid-protein membranes within the smooth endoplasmic reticulum (while it remains in the chrysalis), that likely form cubic membranes, folded according to the form of the Gyroid. The subsequent formation of the chiral hard chitin framework is suggested to be driven by the gradual polymerisation of the chitin precursors, whose inherent chiral assembly in solution (during growth) promotes the formation of a single enantiomer.

Circular dichroism in biological photonic crystals and cubic chiral nets.

Nature provides impressive examples of chiral photonic crystals, with the notable example of the cubic so-called srs network (the label for the chiral degree-three network modeled on SrSi2) or gyroid structure realized in wing scales of several butterfly species. By a circular polarization analysis of the band structure of such networks, we demonstrate strong circular dichroism effects: The butterfly srs microstructure, of cubic I4(1)32 symmetry, shows significant circular dichroism for blue to ultraviolet light, that warrants a search for biological receptors sensitive to circular polarization. A derived synthetic structure based on four like-handed silicon srs nets exhibits a large circular polarization stop band of a width exceeding 30%. These findings offer design principles for chiral photonic devices.

Effect of pregnancy and foetal number on diameter of corpus luteum, maternal progesterone concentration and oxidant/antioxidant balance in ewes.

The aim of this study was to determine the changes in diameter of corpus luteum (CL), maternal progesterone (P) concentration, lipid peroxidation and non-enzymatic antioxidant levels along with enzymatic antioxidant activities in pregnant ewes bearing single and twin foetuses. The ewes were selected from healthy animals that were brought to the abattoir for slaughtering. The ewes were divided into three groups: Group 1 (non-pregnant, non-oestrous, n = 30), Group 2 (pregnant bearing a single foetus, n = 30) and Group 3 (pregnant bearing twin foetuses, n = 12) after they were slaughtered. Pregnant ewes were in the first half of the pregnancy. The diameter of CL and P concentration of pregnant ewes bearing a single foetus or twin foetuses were found higher than that found in non-pregnant ewes. Similarly, the P concentration of pregnant ewes bearing twin foetuses was higher than that found in pregnant ewes bearing a single foetus. Malondialdehyde (MDA) level in pregnant ewes bearing twin foetuses was higher than that found in both non-pregnant and pregnant ewes bearing a single foetus. The serum glutathione (GSH) level and glutathione-peroxidase (GSH-Px) activity of pregnant ewes bearing twin foetuses were found lower than that found in non-pregnant ewes. Additionally, the GSH-Px activity of pregnant ewes bearing twin foetuses was found lower than that found in pregnant ewes bearing a single foetus. No significant difference was found between pregnant ewes bearing female and male foetus with respect to diameter of CL, P concentration and oxidative stress parameters. There were significant positive correlations between foetal number (0, 1, 2) and diameter of CL, P concentration, MDA level, and between P concentration and diameter of CL, MDA level. However, significant negative correlations were found between foetal number (0, 1, 2) and GSH level, GSH-Px activity, and between P concentration and GSH-Px activity. In conclusion, the diameter of CL enlarges, P production increases and oxidant/antioxidant balance impairs because of the gestation stress in ewes during pregnancy.

Both intrathymic and peripheral selection modulate the differential expression of V beta 5 among CD4+ and CD8+ T cells.

Murine T cells expressing V beta 5 are characterized by (a) intrathymic deletion in the presence of I-E and products of endogenous mouse mammary tumor viruses, and (b) a greater representation in CD8+ relative to CD4+ peripheral T cells, thought to be due to more efficient intrathymic positive selection on class I rather than class II major histocompatibility complex antigens. We have engineered mice that are transgenic for a rearranged gene encoding a V beta 5+ beta chain of the T cell receptor for antigen. Deletion is not predicted in I-E- V beta 5+ transgenic mice, and until the age of 2 wk, the CD4/CD8 ratio of peripheral T cells is > 3:1 and indistinguishable between transgenic and nontransgenic mice. Transgenic mice then show a rapid, age-dependent decline in the ratio of CD4+ to CD8+ T cells in the lymphoid periphery, reaching a low of 1:10 by 7 mo of age. Furthermore, the percent of peripheral CD4+ cells that express the transgene drops with age, reaching a low of about 60% at 7 mo, while the percent of CD8+ cells that express V beta 5 remains greater than 95% at all ages. The lymphoid periphery is implicated in this selection against CD4+ V beta 5+ T cells as it occurs more rapidly in thymectomized transgenic mice, and can be delayed in mice whose peripheral T cells are replaced by recent thymic emigrants after depletion by in vivo treatment with anti-Thy-1 antibodies. These results indicate that the relative expression of V beta 5 in T cell subsets can be influenced not only intrathymically in I-E+ V beta 5+ transgenic mice, but also by events in the periphery, in the absence of I-E expression.

Tensorial Minkowski functionals and anisotropy measures for planar patterns.

Quantitative measures for anisotropic characteristics of spatial structure are needed when relating the morphology of microstructured heterogeneous materials to tensorial physical properties such as elasticity, permeability and conductance. Tensor-valued Minkowski functionals, defined in the framework of integral geometry, provide a concise set of descriptors of anisotropic morphology. In this article, we describe the robust computation of these measures for microscopy images and polygonal shapes. We demonstrate their relevance for shape description, their versatility and their robustness by applying them to experimental data sets, specifically microscopy data sets of non-equilibrium stationary Turing patterns and the shapes of ice grains from Antarctic cores.

Bioinformatic analysis of post-transmission viral readaptation in Argentine patients with acute HIV-1 infection.

During the acute phase of HIV-1 infection, a strong readaptation occurs in the viral population. Our objective was to analyze the post-transmission mutations associated with escape to the cytotoxic immune response and its relationship with the progression of the infection. In this study, a total of 17 patients were enrolled during acute/early primary HIV infection and 8 subjects that were the HIV positive partner resulting in 8 transmission pairs. Genotyping of the genetic polymorphisms of HLA class I A and B was performed using PCR-SSOP. Viral RNA extraction was from plasma. 570 single Gag-gene amplifications were obtained by limiting-dilution RT-PCR. Epitope prediction was performed with NetMHC CBS prediction server for the 19 HLA-A and B alleles. Cytotoxic response prediction was performed by using the IEDB Analysis Resource. From our results, we deduce that the transmitted CTL / gag escape frequency in the founder virus was at least double compared to the post-transmission events. Additionally, by means of an algorithm that combines these frequencies, we observed that the founder viruses better adapted to the HLA A / B alleles of the recipient could contribute to a greater progression of the infection. Our results suggest that there is a large adaptation of HIV-1 to the HLA A / B alleles prevalent in our population. However, despite this adaptive advantage, the virus needs to make "readjustments" through new escape and compensatory mutations. Interestingly, according to our results, this readaptation could have a role in the progression of the infection.

Negative effect of feeding with high energy diets on testes and metabolic blood parameters of male Japanese quails, and positive role of milk thistle seed.

In this study, it was aimed to investigate the changes in testicular tissue and cell count, testicular oxidative stress and some metabolic blood parameters of male broiler Japanese quails fed with high energy diet and milk thistle (Silybum marianum) seed. One hundred-twenty male 15-day-old Japanese quail chicks were divided into 4 equal groups with 30 each. The applications in each group were repeated 3 times with 10 animals each. Control group was fed with basal diet. Milk thistle seed group was fed with diet including 1% milk thistle seed. High energy diet group was fed with high energy diet including 10% corn syrup. High energy diet + milk thistle seed group was fed with high energy diet including 10% corn syrup along with 1% milk thistle seed. The feeding period in all groups was 35 days. When the quails reached 50 days old, a total of 48, 12 from each group (4 from each replication) were euthanized and blood samples and testes were collected. Compared with the control group, significant increases in body weight, serum cholesterol and glucose level, aspartate aminotransferase activity and testicular malondialdehyde level; however, significant decreases in serum testosterone level, testicular glutathione peroxidase activity, counts of round and elongated spermatid and sperm as well as histopathologically, significant decreases in seminiferous tubular diameter and seminiferous epithelium thickness, and marked disorganization in germinal cells were determined in quails fed with high energy diet. It was observed that almost all of the disturbances in testicular tissue, cell number, oxidant-antioxidant balance and metabolic blood parameters caused by feeding with high energy diet were significantly prevented by supplementation of milk thistle seed to the diet with high energy. On the other hand, alone milk thistle seed and high energy diet + milk thistle seed administrations decreased body weight in comparison to control and high energy diet groups. As a result, feeding with high energy diet causes disturbances in testes of male quails by affecting liver metabolic functions and testicular oxidant-antioxidant balance, but milk thistle seed addition to diet plays a protective role.

Total selenium and selenomethionine in pharmaceutical yeast tablets: assessment of the state of the art of measurement capabilities through international intercomparison CCQM-P86.

Results of an international intercomparison study (CCQM-P86) to assess the analytical capabilities of national metrology institutes (NMIs) and selected expert laboratories worldwide to accurately quantitate the mass fraction of selenomethionine (SeMet) and total Se in pharmaceutical tablets of selenised-yeast supplements (produced by Pharma Nord, Denmark) are presented. The study, jointly coordinated by LGC Ltd., UK, and the Institute for National Measurement Standards, National Research Council of Canada (NRCC), was conducted under the auspices of the Comité Consultatif pour la Quantité de Matière (CCQM) Inorganic Analysis Working Group and involved 15 laboratories (from 12 countries), of which ten were NMIs. Apart from a protocol for determination of moisture content and the provision of the certified reference material (CRM) SELM-1 to be used as the quality control sample, no sample preparation/extraction method was prescribed. A variety of approaches was thus used, including single-step and multiple-step enzymatic hydrolysis, enzymatic probe sonication and hydrolysis with methanesulfonic acid for SeMet, as well as microwave-assisted acid digestion and enzymatic probe sonication for total Se. For total Se, detection techniques included inductively coupled plasma (ICP) mass spectrometry (MS) with external calibration, standard additions or isotope dilution MS (IDMS), inductively coupled plasma optical emission spectrometry , flame atomic absorption spectrometry and instrumental neutron activation analysis. For determination of SeMet in the tablets, five NMIs and three academic/institute laboratories (of a total of five) relied upon measurements using IDMS. For species-specific IDMS measurements, an isotopically enriched standard of SeMet (76Se-enriched SeMet) was made available. A novel aspect of this study relies on the approach used to distinguish any errors which arise during analysis of a SeMet calibration solution from those which occur during analysis of the matrix. To help those participants undertaking SeMet analysis to do this, a blind sample in the form of a standard solution of natural abundance SeMet in 0.1 M HCl (with an expected value of 956 mg kg(-1) SeMet) was provided. Both high-performance liquid chromatography (HPLC)-ICP-MS or gas chromatography (GC)-ICP-MS and GC-MS techniques were used for quantitation of SeMet. Several advances in analytical methods for determination of SeMet were identified, including the combined use of double IDMS with HPLC-ICP-MS following extraction with methanesulfonic acid and simplified two-step enzymatic hydrolysis with protease/lipase/driselase followed by HPLC-ICP-IDMS, both using a species-specific IDMS approach. Overall, satisfactory agreement amongst participants was achieved; results averaged 337.6 mg kg(-1) (n = 13, with a standard deviation of 9.7 mg kg(-1)) and 561.5 mg kg(-1) (n = 11, with a standard deviation of 44.3 mg kg(-1)) with median values of 337.6 and 575.0 mg kg(-1) for total Se and SeMet, respectively. Recovery of SeMet from SELM-1 averaged 95.0% (n = 9). The ability of NMIs and expert laboratories worldwide to deliver accurate results for total Se and SeMet in such materials (selensied-yeast tablets containing approximately 300 mg kg(-1) Se) with 10% expanded uncertainty was demonstrated. The problems addressed in achieving accurate quantitation of SeMet in this product are representative of those encountered with a wide range of organometallic species in a number of common matrices.

Effect of exogenous GnRH at the time of artificial insemination on reproductive performance of Awassi ewes synchronized with progestagen-PMSG-PGF2alpha combination.

This study was carried out to investigate the efficacy of PGF(2alpha) for oestrus synchronization (ES) in Awassi ewes to which were administered the progestagen-PMSG combination, and to evaluate the effect of the exogenous GnRH administration immediately after the artificial insemination (AI) on their pregnancy rate and lambing performance during the breeding season. The ewes (n = 33) were treated with an intravaginal sponge impregnated with 30 mg fluorogestane acetate for 12 days and were injected with 500 IU PMSG at the time of removal of the sponge. The ewes were then divided into three equal groups of 11 ewes each. One millilitre of physiological saline (0.9% NaCl; placebo) was administered to each ewe in Group 1 at the time of second AI. Approximately 4 microg GnRH (busereline) was injected to each ewe in Group 2 immediately after second AI. A total of 150 microg PGF(2alpha) (cloprostenole) was injected at the time of sponge removal on day 12 and 4 microg GnRH immediately after the second AI was also treated to each ewe in Group 3. Intracervical AI with diluted fresh semen was performed twice at 12 and 24 h following the onset of oestrus. The injection-oestrus onset and injection-oestrus-end interval in Group 3 was significantly (p < 0.001) shorter than both Groups 1 and 2. Although the pregnancy rates of Groups 2 and 3 (81.8%; 9/11) were numerically higher than of Group 1 (63.6%; 7/11), the difference among the groups was statistically insignificant. The multiple birth rate of Group 3 was found higher than Groups 1 and 2. However, the number of single lambs of Group 1 was also higher than Groups 2 and 3 (p < 0.05). Despite the litter sizes of Groups 2 (1.27; 14/11) and 3 (1.55; 17/11) being numerically higher than Group 1 (0.73; 8/11), the differences among all the groups were statistically insignificant. In conclusion, the administration of PGF(2alpha) at the time of removal of the sponge shortens the injection oestrus-onset and oestrus-end interval in Awassi ewes treated with progestagen-PMSG. Additionally, exogenous GnRH treatment immediately after the AI increases the multiple birth rate of Awassi ewes synchronized with progestagen-PMSG-PGF(2alpha) combination.

Examination of real-time PCR for HIV-1 RNA and DNA quantitation in patients infected with HIV-1 BF intersubtype recombinant variants.

The impact of HIV-1 genetic diversity on the performance of laboratory testing is an issue that has to be monitored continuously. An "in-house" real-time PCR assay was developed by the Agence Nationale de Recherche sur le SIDA (ANRS) in France for viral load (VL) quantitation based on the amplification of the HIV-1 long terminal repeat (LTR) region. This technology has not been used in Argentina yet and considering the HIV-1 diversity in the country, a comparative analysis of this assay was undertaken versus the Versant HIV-1 RNA 3.0 Assay (b-DNA). The performance was assessed on 30 drug-naïve HIV-1 infected patients who were characterized previously by phylogenetic analysis of the pol and vpu gene. The results showed that there is a significant linear correlation between values of transformed viral load logarithms measured by both, bDNA and real-time PCR assay and that this assay can be used to quantify viral load in samples from BF-infected patients with the same accuracy and reliability as for B subtype samples. The use of "in-house" real-time PCR to measure DNA in PBMCs correlated strongly with the HIV-1 RNA levels in all specimens.