Follicle profile and plasma gonadotropin concentration in pubertal female ponies

Twelve female ponies were examined daily for 30 days and classified as ovulating (OV; N = 6; 197 ± 6 kg) or prepubertal (PP; N = 6; 196 ± 9 kg). Follicles were detected by ultrasound and gonadotropins quantified by radioimmunoassay. The mean diameter of the largest follicles was significantly larger in OV (38 ± 1 mm) than in PP (26 ± 2 mm) but there was no difference between groups in the size of the second largest follicle. There were more small follicles (<24 mm) in the PP than in the OV group, but PP fillies had a smaller number of follicles >29 mm than the OV fillies. Follicle-stimulating hormone (FSH) levels did not differ between groups but PP fillies had lower luteinizing hormone (LH) peak (8 ± 1 ng/ml) and basal (4 ± 0.5 ng/ml) levels, lower peak magnitude (2 ± 0.2 ng/ml) and period average (5 ± 0.6 ng/ml) than OV fillies (32 ± 4.5, 8 ± 1.2, 17.1 ± 6, and 15 ± 2.3 ng/ml, respectively). The PP group, in contrast to the OV group, showed no relationship between FSH surge and follicle wave emergence. We conclude that an LH concentration higher than 8 ng/ml is needed for follicle growth to a preovulatory size. Wave emergence and FSH secretion seem to be independent events, probably due to an inhibitory neural system in these PP animals. PP fillies may provide a physiological model for the study of follicle wave emergence which apparently does not depend on gonadotropin levels.

Concentration of CCL11, CXCL8 and TNF-alpha in sputum and plasma of patients undergoing asthma or chronic obstructive pulmonary disease exacerbation

Asthma and chronic obstructive pulmonary disease (COPD) are common respiratory illnesses characterized by chronic inflammation of the airways. The characterization of induced or spontaneously produced sputum is a useful technique to assess airway inflammation. In the present study, we compared the concentrations of CCL2, CCL11, CXCL8, and tumor necrosis factor-alpha (TNF-alpha) in plasma and induced sputum of patients with severe asthma or COPD and correlated the levels of these mediators with inflammatory cells in sputum. Asthmatic patients had elevated levels of eosinophils (40.1 ± 6.24%) in sputum whereas neutrophils (63.3 ± 4.66%) predominated in COPD patients. The levels of the chemokine CCL11 were markedly increased in sputum (708.7 ± 330.7 pg/ml) and plasma (716.6 ± 162.2 pg/ml) of asthmatic patients and correlated with the percentage of eosinophils in induced sputum. The concentrations of CXCL8 (817.0 ± 105.2 pg/ml) and TNF-alpha (308.8 ± 96.1 pg/ml) were higher in sputum of COPD patients and correlated with the percentage of neutrophils in induced sputum. There was also an increase in the concentrations of CXCL8 (43.2 ± 6.8 pg/ml) in sputum of asthmatic patients. These results validate that sputum is a suitable method to assess chemokines and cytokines associated with asthma and COPD. Moreover, the mechanisms involved in the synthesis of CCL11 and CXCL8/TNF-alpha would be helpful to better understand the inflammatory profile associated with asthma and COPD, respectively.

The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ß-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r² = 0.9996, average recovery between 92.3 to 108.3% and quantification limits of 1.0 µmol/L. Hcy concentrations >15 µmol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 ± 3.3 µmol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.

Influence of different sanitizers on food contaminant bacteria: effect of exposure temperature, contact time, and product concentration

The efficiency of four Sanitizers - peracetic acid, chlorhexidine, quaternary ammonium, and organic acids - was tested in this work using different bacteria recognized as a problem to meat industry, Salmonella sp., S. aureus, E. coli and L. monocytogenes. The effects of sanitizer concentration (0.2, 0.5, 0.6, 1.0, 1.1 and 1.4%), at different temperatures (10 and 45 °C) and contact time (2, 10, 15, 18 and 25 minutes) were evaluated. Tests in an industrial plant were also carried out considering previously obtained results. In a general way, peracetic acid presented higher efficiencies using low concentration (0.2%) and contact time (2 minutes) at 10 °C. The tests performed in industrial scale showed that peracetic acid presented a good performance in concentration and contact time lower than that suggested by the suppliers. The use of chlorhexidine and quaternary ammonium led to reasonable results at the indicated conditions, and organic acids were ineffective under concentration and contact time higher than those indicated by the suppliers in relation to Staphylococcus aureus. The results, in general, show that the choice for the most adequate sanitizer depends on the microorganism contaminant, the time available for sanitizer application, and also on the process cost.

Arsenic speciation by ion-exchange chromatography with on- line determination by hydride generation: electronic modification of the D.C. plasma by photon counting

A method using L-cysteine for the determination of arsenous acid (As(III)), arsenic acid (As(V)), monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) by hydride generation was demonstrated. The instrument used was a d.c. plasma atomic emission spectrometer (OCP-AES). Complete recovery was reported for As(III), As(V), and DMAA while 86% recovery was reported for MMAA. Detection limits were determined, as arsenic for the species listed previously, to be 1.2, 0.8, 1.1, and 1.0 ngemL-l, respectively. Precision values, at 50 ngemL-1 arsenic concentration, were f.80/0, 2.50/0, 2.6% and 2.6% relative standard deviation, respectively. The L-cysteine reagent was compared directly with the conventional hydride generation technique which uses a potassium iodide-hydrochloric acid medium. Recoveries using L-cysteine when compared with the conventional method provided the following results: similar recoveries were obtained for As(III), slightly better recoveries were obtained for As(V) and MMAA, and significantly better recoveries for DMAA. In addition, tall and sharp peak shapes were observed for all four species when using L-cysteine. The arsenic speciation method involved separation by ion exchange .. high perfonnance liquid chromatography (HPLC) with on-line hydride generation using the L.. cysteine reagent and measurement byOCP-AES. Total analysis time per sample was 12 min while the time between the start of subsequent runs was approximately 20 min. A binary . gradient elution program, which incorporated the following two eluents: 0.01 and 0.5 mM tri.. sodium citrate both containing 5% methanol (v/v) and both at a pH of approximately 9, was used during the separation by HPLC. Recoveries of the four species which were measured as peak area, and were normalized against As(III), were 880/0, 290/0, and 40% for DMAA, MMAA and As(V), respectively. Resolution factors between adjacent analyte peaks of As(III) and DMAA was 1.1; DMAA and MMAA was 1.3; and MMAA and As(V) was 8.6. During the arsenic speciation study, signals from the d.c. plasma optical system were measured using a new photon-signal integrating device. The_new photon integrator developed and built in this laboratory was based on a previously published design which was further modified to reflect current available hardware. This photon integrator was interfaced to a personal computer through an AID convertor. The .photon integrator has adjustable threshold settings and an adjustable post-gain device.

Development and characterization of concentric capillary nebulizer used in inductively coupled plasma analysis /

A simple, low-cost concentric capillary nebulizer (CCN) was developed and evaluated for ICP spectrometry. The CCN could be operated at sample uptake rates of 0.050-1.00 ml min'^ and under oscillating and non-oscillating conditions. Aerosol characteristics for the CCN were studied using a laser Fraunhofter diffraction analyzer. Solvent transport efficiencies and transport rates, detection limits, and short- and long-term stabilities were evaluated for the CCN with a modified cyclonic spray chamber at different sample uptake rates. The Mg II (280.2nm)/l\/lg 1(285.2nm) ratio was used for matrix effect studies. Results were compared to those with conventional nebulizers, a cross-flow nebulizer with a Scott-type spray chamber, a GemCone nebulizer with a cyclonic spray chamber, and a Meinhard TR-30-K3 concentric nebulizer with a cyclonic spray chamber. Transport efficiencies of up to 57% were obtained for the CCN. For the elements tested, short- and long-term precisions and detection limits obtained with the CCN at 0.050-0.500 ml min'^ are similar to, or better than, those obtained on the same instrument using the conventional nebulizers (at 1.0 ml min'^). The depressive and enhancement effects of easily ionizable element Na, sulfuric acid, and dodecylamine surfactant on analyte signals with the CCN are similar to, or better than, those obtained with the conventional nebulizers. However, capillary clog was observed when the sample solution with high dissolved solids was nebulized for more than 40 min. The effects of data acquisition and data processing on detection limits were studied using inductively coupled plasma-atomic emission spectrometry. The study examined the effects of different detection limit approaches, the effects of data integration modes, the effects of regression modes, the effects of the standard concentration range and the number of standards, the effects of sample uptake rate, and the effect of Integration time. All the experiments followed the same protocols. Three detection limit approaches were examined, lUPAC method, the residual standard deviation (RSD), and the signal-to-background ratio and relative standard deviation of the background (SBR-RSDB). The study demonstrated that the different approaches, the integration modes, the regression methods, and the sample uptake rates can have an effect on detection limits. The study also showed that the different approaches give different detection limits and some methods (for example, RSD) are susceptible to the quality of calibration curves. Multicomponents spectral fitting (MSF) gave the best results among these three integration modes, peak height, peak area, and MSF. Weighted least squares method showed the ability to obtain better quality calibration curves. Although an effect of the number of standards on detection limits was not observed, multiple standards are recommended because they provide more reliable calibration curves. An increase of sample uptake rate and integration time could improve detection limits. However, an improvement with increased integration time on detection limits was not observed because the auto integration mode was used.

Time resolved study of CN band emission from plasma generated by laser irradiation of graphite

Time and space resolved studies of emission from CN molecules have been carried out in the plasma produced from graphite target by 1.06 urn pulses from a Q-switched Nd:YAG laser. Depending on the laser pulse energy, time of observation and position of the sampled volume of the plasma, the features of the emission spectrum are found to change drastically. The vibrational temperature and population distribution in the different vibrational levels have been studied as functions of distance, time, laser energy and ambient gas pressure. Evidence for nonlinear effects of the plasma medium such as self focusing which exhibits threshold-like behaviour are also obtained. Temperature and electron density of the plasma have been evaluated using the relative line intensities of successive ionization stages of carbon atom. These electron density measurements are verified by using Stark broadening method.

Time Resolved Analysis of C2 Emission from Laser Induced Graphite Plasma in Helium Atmosphere

We report time resolved study of C2 emission from laser produced carbon plasma in presence of ambient helium gas. The 1.06µm: radiation from a Nd:YAG laser was focused onto a graphite target where it·produced a transient plasma. We observed double peak structure in the time profile of C2 species. The twin peaks were observed only after a threshold laser fluence. It is proposed that the faster velocity component in the temporal profiles originates mainly due to recombination processes. The laser fluence and ambient gas dependence of the double peak intensity distribution is also reported.

Spatial and time resolved analysis of CN bands in the laser induced plasma from graphite

Analysis of the emission bands of the CN molecules in the plasma generated from a graphite target irradiated with 1-06/~m radiation pulses from a Q-switched Nd:YAG laser has been done. Depending on the position of the sampled volume of the plasma plume, the intensity distribution in the emission spectra is found to change drastically. The vibrational temperature and population distribution in the different vibrational levels have been studied as function of distance from the target for different time delays with respect to the incidence of the laser pulse. The translational temperature calculated from time of flight is found to be higher than the observed vibrational temperature for CN molecules and the reason for this is explained.

Identification of stimulatory and inhibitory inputs to the hypothalamic-pituitary-adrenal axis during hypoglycaemia or transport in ewes

This study used the novel approach of statistical modelling to investigate the control of hypothalamic-pituitary-adrenal (HPA) axis and quantify temporal relationships between hormones. Two experimental paradigms were chosen, insulin-induced hypoglycaemia and 2 h transport, to assess differences in control between noncognitive and cognitive stimuli. Vasopressin and corticotropin-releasing hormone (CRH) were measured in hypophysial portal plasma, and adrenocorticotropin hormone (ACTH) and cortisol in jugular plasma of conscious sheep, and deconvolution analysis was used to calculate secretory rates, before modelling. During hypoglycaemia, the relationship between plasma glucose and vasopressin or CRH was best described by log(10) transforming variables (i.e. a positive power-curve relationship). A negative-feedback relationship with log(10) cortisol concentration 2 h previously was detected. Analysis of the 'transport' stimulus suggested that the strength of the perceived stimulus decreased over time after accounting for cortisol facilitation and negative-feedback. The time course of vasopressin and CRH responses to each stimulus were different However, at the pituitary level, the data suggested that log(10) ACTH secretion rate was related to log(10) vasopressin and CRH concentrations with very similar regression coefficients and an identical ratio of actions (2.3 : 1) for both stimuli. Similar magnitude negative-feedback effects of log(10) cortisol at -110 min (hypoglycaemia) or -40 min (transport) were detected, and both models contained a stimulatory relationship with cortisol at 0 min (facilitation). At adrenal gland level, cortisol secretory rates were related to simultaneously measured untransformed ACTH concentration but the regression coefficient for the hypoglycaemia model was 2.5-fold greater than for transport. No individual sustained maximum cortisol secretion for longer than 20 min during hypoglycaemia and 40 min during transport. These unique models demonstrate that corticosteroid negative-feedback is a significant control mechanism at both the pituitary and hypothalamus. The amplitude of HPA response may be related to stimulus intensity and corticosteroid negative-feedback, while duration depended on feedback alone.

Long-term monounsaturated fatty acid diets reduce platelet aggregation in healthy young subjects

The aim of the present study was to compare the response of a range of atherogenic and thrombogenic risk markers to two dietary levels of saturated fatty acid (SFA) substitution with monounsaturated fatty acids (MUFA) in students living in a university hall of residence. Although the benefits of such diets have been reported for plasma lipoproteins in high-risk groups, more needs to be known about effects of more modest SFA-MUFA substitutions over the long term and in young healthy adults. In a parallel design over 16 weeks, fifty-one healthy young subjects were randomised to one of two diets: (1) a moderate-MUFA diet in which 16 g dietary SFA/100 g total fatty acids were substituted with MUFA (n 25); (2) a high-MUFA diet in which 33 g dietary SFA/100 g total fatty acids were substituted with MUFA (n 26). All subjects followed an 8-week run-in diet (reference diet), with a fatty acid composition close to the UK average values. There were no differences in plasma lipid responses between the two diets over 16 weeks of the study with similar reductions in total cholesterol (P<0.001) and LDL-cholesterol (P<0.01) in both groups; a small but significant reduction in HDL-cholesterol was also observed in both groups (P<0.01). Platelet responses to ADP (P<0.01) and arachidonic acid (P<0.05) differed with time on the two diets; at 16 weeks, platelet aggregatory response to ADP was significantly lower on the high-MUFA than the moderate-MUFA (P<0.01) diet; ADP responses were also significantly lower within this group at 8 (P< 0.05) and 16 (P< 0.01) weeks compared with baseline. There were no differences in fasting factor VII activity (factors VIII and VIIag), fibrinogen concentration or tissue-type plasminogen activator activity between the diets. There were no differences in postprandial factor VIII responses to a standard meal (area under the curve) between the diets after 16 weeks, but postprandial factor VIII response was lower than on the high-MUFA diet compared with baseline (P<0.01). In conclusion, a high-MUFA diet sustains potentially beneficial effects on platelet aggregation and postprandial activation of factor VII. Moderate or high substitution of MUFA for SFA achieves similar reductions in fasting blood lipids in young healthy subjects.

Noncompetitive plasma biokinetics of deuterium-labeled natural and synthetic alpha-tocopherol in healthy men with an apoE4 genotype

Previous studies comparing the biokinetics of deuterated natural (RRR) and synthetic (all-rac) α-tocopherol (vitamin E) used a simultaneous ingestion or competitive uptake approach and reported relative bioavailability ratios close to 2:1, higher than the accepted biopotency ratio of 1.36:1. The aim of the current study was to compare the biokinetics of deuterated natural and synthetic vitamin E using a noncompetitive uptake model both before and after vitamin E supplementation in a distinct population. Healthy men (n = 10) carrying the apolipoprotein (apo)E4 genotype completed a randomized crossover study, comprised of two 4-wk treatments with 400 mg/d (RRR-α-tocopheryl and all-rac-α-tocopheryl acetate) with a 12-wk washout period between treatments. Before and after each treatment period, the subjects consumed a capsule containing 150 mg deuterated α-tocopheryl acetate in either the PRR or all-rac form depending on their treatment regimen. Blood was obtained up to 48 h after ingestion, and tocopherols analyzed by LC/MS. After deuterated all-rac administration, plasma deuterated tocopherol maximum concentrations and area under the concentration vs. time curves (AUC) were lower than those following RRR administration. The RRR:all-rac ratios determined from the deuterated biokinetic profiles (maximum concentration; C-max) and AUCs were 1.35:1 &PLUSMN; 0.17 and 1.33:1 &PLUSMN; 0.18, respectively. The 4-wk supplementation with either PRR or all-rac significantly increased plasma a-tocopherol concentrations (P < 0.001), but decreased the plasma response to newly absorbed deuterated RRR or all-rac α-tocopherol. Using a noncompetitive uptake approach, the relative bioavailability of natural to synthetic vitamin E in apoE4 males was close to the currently accepted biopotency ratio of 1.36:1.

Plasma ghrelin and oxytomodulin concentrations in lactating dairy cows receiving abomasal soybean oil, corn starch, and casein infusions

The effects of increased postruminal supply of casein, corn starch, and soybean oil on plasma concentrations of the gastrointestinal hormones ghrelin and oxyntomodulin (OXM) were investigated. Four mid-lactation Holstein cows were used in a 4×4 Latin square. Treatments were continuous abomasal infusions (23h/d) for 7 d of water, soybean oil (500g/d), corn starch (1100g/d), or casein (800g/d). Jugular vein plasma was obtained every 30min for 7h on days 1 and 7. Soybean oil and casein infusion decreased preprandial plasma ghrelin concentration by approximately 20% on both d (time-by-treatment P<0.10); however, dry matter intake (DMI) was depressed only after 7 d of oil infusion. Infusion of soybean oil, corn starch, or casein did not change the plasma OXM concentration (P>0.20). The present data indicate that plasma ghrelin concentration is depressed immediately before feeding by the postruminal infusion of soybean oil and casein, but it is not affected during the postprandial period. Plasma ghrelin concentration was not altered (P>0.20), pre- or postfeeding, by increased postruminal supply of corn starch. In addition, plasma OXM concentration did not respond (P>0.20) to postruminal nutrient infusion. In conclusion, a decrease in DMI when fat is infused could be partially explained by the decrease in prefeeding plasma ghrelin concentration, but a decrease in prefeeding plasma ghrelin concentration is not always associated with a decrease in DMI, as observed for the infusion of casein. Plasma OXM concentration was not affected by postruminal infusion of macronutrients.

Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events

We report high-resolution observations of the southward-IMF cusp/cleft ionosphere made on December 16th 1998 by the EISCAT (European incoherent scatter) Svalbard radar (ESR), and compare them with observations of dayside auroral luminosity, as seen at a wavelength of 630 nm by a meridian scanning photometer at Ny Alesund, and of plasma flows, as seen by the CUTLASS (co-operative UK twin location auroral sounding system) Finland HF radar. The optical data reveal a series of poleward-moving transient red-line (630 nm) enhancements, events that have been associated with bursts in the rate of magnetopause reconnection generating new open flux. The combined observations at this time have strong similarities to predictions of the effects of soft electron precipitation modulated by pulsed reconnection, as made by Davis and Lockwood (1996); however, the effects of rapid zonal flow in the ionosphere, caused by the magnetic curvature force on the newly opened field lines, are found to be a significant additional factor. In particular, it is shown how enhanced plasma loss rates induced by the rapid convection can explain two outstanding anomalies of the 630 nm transients, namely how minima in luminosity form between the poleward-moving events and how events can re-brighten as they move poleward. The observations show how cusp/cleft aurora and transient poleward-moving auroral forms appear in the ESR data and the conditions which cause enhanced 630 nm emission in the transients: they are an important first step in enabling the ESR to identify these features away from the winter solstice when supporting auroral observations are not available.