Effects of a synthetic prostaglandin analogue, cloprostenol, on the corpus luteum of the guinea pig

The effects of a synthetic prostaglandin analogue, cloprostenol, on luteal function in a guinea pig were studied. At a dose of 250μg, cloprostenol administered I-P on day 9 of the oestrous cycle caused a reduction in the length of the oestrous cycle from 17.4±s.d. 0.9 to 14.5±1.1 days (p<0.01). Lower doses were ineffective, and post-treatment cycles were not different in length from pre-treatment cycles. Cloprostenol also caused a dose-dependent reduction in luteal weight, which fell from 3.52±0.82 to 1.82±0.4mg (<0.01) 48 h after administation of a 250μg dose on day 9. Plasma progesterone, measured by radioimmunoassay, was reduced from 4.67±0.59 to 2.69±0.66 ng ml⁻¹(p<0.01) 48 h after administration of 250μg cloprostenol on day 9. 250μg cloprostenol also reduced blood flow per corpus luteum, measured by ⁸⁵Sr-labelled 15μm microspheres, both at 3 h (20.20±10.36 to 9.40±4.2μ1 min⁻¹; p0.05) and at 48 h 18.47±8.27 to 5.23±1.90μl min⁻¹; p<0.01) after administration on day 9. No adverse side-effects were observed at any dose level of cloprostenol used. It was concluded that cloprostenol is a useful experimental luteolysin in the guinea pig.     

Effect of renoguanylin on hydrogen/bicarbonate ion transport in rat renal tubules

Renoguanylin (REN) is a recently described member of the guanylin family, which was first isolated from eels and is expressed in intestinal and specially kidney tissues. In the present work we evaluate the effects of REN on the mechanisms of hydrogen transport in rat renal tubules by the stationary microperfusion method. We evaluated the effect of 1 μM and 10 μM of renoguanylin (REN) on the reabsorption of bicarbonate in proximal and distal segments and found that there was a significant reduction in bicarbonate reabsorption. In proximal segments, REN promoted a significant effect at both 1 and 10 μM concentrations. Comparing control and REN concentration of 1 μM, JHCO₃⁻, nmol cm^− 2 s^− 1 − 1,76 ± 0,11_control × 1,29 ± 0,08_{REN 10 μM}; P < 0.05, was obtained. In distal segments the effect of both concentrations of REN was also effective, being significant e.g. at a concentration of 1 μM (JHCO₃⁻, nmol cm^− 2 s⁻ 1 − 0.80 ± 0.07_control × 0.60 ± 0.06_{REN 1 μM}; P < 0.05), although at a lower level than in the proximal tubule. Our results suggest that the action of REN on hydrogen transport involves the inhibition of Na⁺/H⁺exchanger and H⁺-ATPase in the luminal membrane of the perfused tubules by a PKG dependent pathway.     

Fast liquid chromatographic determination of urinary trans,trans-muconic acid

trans,trans-Muconic acid (1,3-butadiene-1,4-dicarboxylic acid, MA), a minor urinary metabolite of benzene exposure, was determined, after clean-up by solid-phase anion-exchange chromatography, by reversed-phase HPLC on a C₁₈ column (5 × 0.46 cm I.D., 3 μm particle size), using formic acid-tetrahydrofuran-water (14:17:969) as mobile phase and UV detection at 263 nm. The recovery of MA from spiked urine was > 95% in the 50–500 μg/l range; the quantification limit was 6 μg/l; day-to-day precision, at 300 μg/l, C.V. = 9.2%; the run time was less than 10 min. Urinary MA excretion was measured in two spot urine samples of 131 benzene environmentally exposed subjects: midday values obtained in non-smokers (mean±S.D.=77±54 μg/l, N = 82) were statistically different from those of smoerks (169±85 μg/l, N = 30) (P<0.0001); each group showed a statistically significant increase between MA excretion in midday over morning samples. Moreover, in subjects grouped according to tobacco-smoke exposure level, median values of MA were positively associated with and increased with daily smoking habits.     

The effects of water temperature and ration size on growth and body composition of fry of common carp, Cyprinus carpio

Experiment was conducted with the aim of determining the effect of varying water temperature and ration size on growth and body composition of fry of the common carp, Cyprinus carpio. Common carp fry with an initial body weight (BW) of 0.86 g were fed a diet (34.9% protein, 18.3 KJ/g diet) at four ration sizes 4%, 5%, 6% and 7% of their body weight per day and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with 6% ration showed the highest mean final body weight at 28 °C. Final body weight was significantly (P<0.05) affected by ration and temperature. Cyprinus carpio fry raised at 28 °C had higher feed efficiency (FE) (44.36%) than the fry reared at 32 °C (40.98%) with 4% ration. Further, feed efficiency decreased with increase in ration levels in both temperatures. Protein efficiency ratio (PER) was higher (1.26) at 28 °C than at 32 °C (1.17). At 6% ration, common carp fry showed highest specific growth rate (SGR) (3.82%/day) at 28 °C as compared with at 32 °C (3.57%/day). A linear increase in protein and lipid contents was evident with increasing ration levels up to 6% body weight at both temperatures 28 and 32 °C. Second-order polynomial regression analysis of weight gain and SGR indicated the breakpoints at ration level 6.04% and 6.08% body weight per day at 28 and 32 °C. Hepatosomatic index (HSI) not affected by temperature and ration size while, viscerosomatic index (VSI) influenced (P<0.05) by ration size and temperature. Based on the above results, it may be concluded that 6% BW/day ration is optimal for growth of Cyprinus carpio fry at both the temperatures 28 and 32 °C.     

Increased circulating IL-8 is associated with reduced IGF-1 and related to poor metabolic control in adolescents with type 1 diabetes mellitus

Background: A dysregulated growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis is well-recognized in children and adolescents with type 1 diabetes mellitus (T1DM). Decreased IGF-1 levels can also be found in chronic inflammatory diseases, while hyperglycemia promotes inflammatory cytokine production. Therefore, inflammatory cytokines may link poor metabolic control with GH/IGF-1 axis changes. This study examined the relationship between serum inflammatory cytokines and IGF-1 in adolescents (age 13–18) with TIDM in chronic poor (n = 17) or favorable (n = 19) glucose control. Poor control (PC) was defined as 3, consistent HbA1C > 9% during the previous 2 years, while favorable control (FC) was consistent levels of HbA1C < 9%. Results: HbA1C (FC: 7.5 ± 0.6%; PC: 10.5 ± 0.9%, p < 0.001) and interleukin (IL)-8 (FC: 3.7 ± 4.0 pg/ml; PC: 7.4 ± 4.3 pg/ml, p = 0.01) were increased and IGF-1 (FC: 536.5 ± 164.3 ng/ml; PC: 408.9 ± 157.1 ng/ml, p = 0.03) was decreased in patients with poor control compared to patients with favorable control. Moreover, IL-8 was inversely correlated with IGF-1 (r = −0.40, p = 0.03) and positively correlated with HbA1C (r = 0.36, p = 0.03). Conclusions: In adolescents with T1DM and chronic, poor glucose control, increased serum IL-8 is associated with reduced IGF-1 suggesting a pro-inflammatory milieu that may contribute to alterations in the GH/IGF-1 axis.     

Influence of lipoprotein-lipase activity on plasma triacylglycerol concentration and lipid storage in three genotypes of ducks

The lipoprotein-lipase (LPL) hydrolyses the triacylglycerols (TG) secreted by the liver and, thus, allows the storage of lipids onto the extrahepatic tissues. The LPL activity has been studied by injection of LPL antibodies in three genotypes of ducks (Muscovy (Cairina moschat), Pekin (Anas plathyrhynchos) and Mule (hybrids of male Muscovy ducks and female Pekin ducks)) under overfeeding condition. The results show a similar weight gain between injected and control animals. A higher liver steatosis is observed in Mule ducks (616 ± 18 g; 8.79% of body mass (BW)) and Muscovy ducks (514 ± 13 g; 7.05% BW) compared to Pekin ducks (353 ± 21 g; 5.89% BW, p < 0.05). Pekin ducks showed a much marked extrahepatic fattening of abdominal and subcutaneous adipose tissues. The LPL activity was evaluated by comparing the evolution of the plasma TG concentrations after injections of saline (control animals) or injections of specific LPL-antibodies. Inhibition of LPL activity performed by intravenous injections of LPL-antibodies showed a spectacular increase in the plasma TG concentrations in the three genotypes. That increase was considerably higher in Pekin ducks (98 ± 10 g/L) compared to Muscovy ducks (35 ± 2 g/L, p < 0.01) and Mule ducks (30 ± 4 g/L, p < 0.01). Those data suggest that a high export of lipids synthesized in liver and a high LPL activity occur in overfed Pekin ducks, which can favour the extrahepatic fattening to the detriment of the liver steatosis, and conversely in overfed Muscovy and Mule ducks.     

Elderberry flavonoids bind to and prevent H1N1 infection in vitro

A ionization technique in mass spectrometry called Direct Analysis in Real Time Mass Spectrometry (DART TOF-MS) coupled with a Direct Binding Assay was used to identify and characterize anti-viral components of an elderberry fruit (Sambucus nigra L.) extract without either derivatization or separation by standard chromatographic techniques. The elderberry extract inhibited Human Influenza A (H1N1) infection in vitro with an IC₅₀ value of 252 ± 34 μg/mL. The Direct Binding Assay established that flavonoids from the elderberry extract bind to H1N1 virions and, when bound, block the ability of the viruses to infect host cells. Two compounds were identified, 5,7,3′,4′-tetra-O-methylquercetin (1) and 5,7-dihydroxy-4-oxo-2-(3,4,5-trihydroxyphenyl)chroman-3-yl-3,4,5-trihydroxycyclohexanecarboxylate (2), as H1N1-bound chemical species. Compound 1 and dihydromyricetin (3), the corresponding 3-hydroxyflavonone of 2, were synthesized and shown to inhibit H1N1 infection in vitro by binding to H1N1 virions, blocking host cell entry and/or recognition. Compound 1 gave an IC₅₀ of 0.13 μg/mL (0.36 μM) for H1N1 infection inhibition, while dihydromyricetin (3) achieved an IC₅₀ of 2.8 μg/mL (8.7 μM). The H1N1 inhibition activities of the elderberry flavonoids compare favorably to the known anti-influenza activities of Oseltamivir (Tamiflu^®; 0.32 μM) and Amantadine (27 μM).     

Pre-treatment of cattle semen or oocytes with purified milk osteopontin affects in vitro fertilization and embryo development

This study was designed to investigate the effects of pre-incubating cattle spermatozoa or matured oocytes with purified osteopontin (OPN) from cattle milk on fertilization in cattle and embryonic development in vitro. There were two different experiments, semen from six mature Holstein bulls (Bos Taurus) was frozen with different concentrations of OPN (0, 1, 10, 100 μg/mL). Matured cattle oocytes were also pre-treated with OPN (0, 10, 100 μg/mL). In both experiments, pre-treated oocytes or frozen semen, was processed for in vitro fertilization and embryo development. Significantly more oocytes were fertilized when using frozen semen with 10 μg/mL OPN (bull 2 = 85 ± 4% and bull 5 = 78 ± 4%) than without OPN (bull 2 = 75 ± 4% and bull 5 = 69 ± 4%). Those bulls also had increase in cleavage and embryo development (bull 2 = 85 ± 3%, 41 ± 1.9%; bull 5 = 76 ± 2%, 37 ± 1.8%) compared with control (bull 2 = 75 ± 3%, 30 ± 2%; bull 5 = 68 ± 2%, 29 ± 2%). Incubating matured oocytes in 10 μg/mL OPN (87 ± 3%) and 100 μg/mL OPN (88 ± 3%) significantly increased fertilization than control (73 ± 3%). OPN also improve cleavage, and embryo development in treatments with 10 μg/mL OPN (82.7 ± 1.3%; 31.7 ± 1.4%) and 100 μg/mL OPN (85.8 ± 1.3%; 33.8 ± 1.5%) when compared with control (74.1 ± 1.3%; 24.2 ± 1.2%). These data suggest that both, spermatozoa from some bulls and oocytes may associate with OPN, suggesting a facilitory role on in vitro fertilization and embryo development.     

Gas chromatography–electron-capture detection of urinary methylhippuric acid isomers as biomarkers of environmental exposure to xylene

Methylhippuric acid isomers (MHAs), urinary metabolites of xylenes, were determined, after clean-up by C18-SPE and esterification with hexafluoroisopropanol and diisopropylcarbodiimide, by GC with ECD detection, on an SPB-35 capillary column (30 m, 0.32 mm I.D., 0.25 μm film thickness, β=320). S-benzyl-mercapturic acid was used for internal standardization. Chromatographic conditions were: oven temperature 162°C, for 14.2 min; ramp by 30°C/min to 190°C, for 3.5 min; ramp by 30°C/min to 250°C, for 4 min; helium flow rate: 1.7 ml/min; detector and injector temperature: 300°C. The sample (1 μl) was injected with a split injection technique (split ratio 5:1). MHA recovery was >95% in the 0.5–20 μmol/l range; the limit of detection was <0.25 μmol/l; day-to-day precision, at 2 μmol/l, was Cv<10%. Urinary MHAs were determined in subjects exposed to different low-level sources of xylenes: (a) tobacco smoking habit and (b) BTX urban air pollution (airborne xylene ranging from 0.1 to 3.7 μmol/m³). Study (a) showed a significant difference between urinary MHA median excretion values of nonsmokers and smokers (4.6 μmol/l vs. 8.1 μmol/l, p<0.001). Study (b) revealed a significant difference between indoor workers and outdoor workers (4.3 μmol/l vs. 6.9 μmol/l, p<0.001), and evidenced a relationship between MHAs (y, μmol/mmol creatinine) and airborne xylene (x, μmol/m³) (y=0.085+0.34x; r=0.82, p<0.001, n=56). Proposed biomarkers could represent reliable tools to study very low-level exposure to aromatic hydrocarbons such as those observed in the urban pollution due to vehicular traffic or in indoor air quality evaluation.     

Antioxidant activities of flavonol derivatives from the leaves and stem bark of Scutia buxifolia Reiss

This study evaluated the antioxidant activities in the leaves and stem bark fractions of Scutia buxifolia. Cerebral lipid peroxidation (TBARS) was induced by Fe(II) and radical-scavenging activity was determined by DPPH method. Folin–Ciocalteu was used to determine phenolic contents. Quercetin, quercitrin, isoquercitrin and rutin were isolated from leaf ethyl acetate fraction and their levels were measured by high performance liquid chromatography.-photodiode array detector.IC₅₀ (DPPH) varied from 4.35 ± 1.30 to 29.55 ± 0.54 μg/mL for stem bark and from 6.50 ± 0.40 to 30.54 ± 1.14 in the leaves. Ethyl acetate and butanolic fractions caused a sharp fall in TBARS production with IC₅₀ from 2.93 ± 2.17 to 40.46 ± 2.51 μg/mL for the leaves and 0.66 ± 0.17 to 27.3 ± 1.23 for the stem bark. Results obtained indicated that S. buxifolia has a great potential to prevent disease caused by the overproduction of free radicals and also it might be used as a potential source of natural antioxidant agents.     

Long-term exposure of the freshwater shrimp Macrobrachium olfersii to elevated salinity: Effects on gill (Na,K)-ATPase α-subunit expression and K-phosphatase activity

The kinetic properties of a microsomal gill (Na⁺,K⁺)-ATPase from the freshwater shrimp, Macrobrachium olfersii, acclimated to 21‰ salinity for 10 days were investigated using the substrate p-nitrophenylphosphate. The enzyme hydrolyzed this substrate obeying cooperative kinetics at a rate of 123.6 ± 4.9 U mg^− 1 and K_0.5 = 1.31 ± 0.05 mmol L^− 1. Stimulation of K⁺-phosphatase activity by magnesium (V_max = 125.3 ± 7.5 U mg^− 1; K_0.5 = 2.09 ± 0.06 mmol L^− 1), potassium (V_max = 134.2 ± 6.7 U mg^− 1; K_0.5 = 1.33 ± 0.06 mmol L^− 1) and ammonium ions (V_max = 130.1 ± 5.9 U mg^− 1; K_0.5 = 11.4 ± 0.5 mmol L^− 1) was also cooperative. While orthovanadate abolished p-nitrophenylphosphatase activity, ouabain inhibition reached 80% (K_I = 304.9 ± 18.3 μmol L^− 1). The kinetic parameters estimated differ significantly from those for freshwater-acclimated shrimps, suggesting expression of different isoenzymes during salinity adaptation. Despite the ≈2-fold reduction in K⁺-phosphatase specific activity, Western blotting analysis revealed similar α-subunit expression in gill tissue from shrimps acclimated to 21‰ salinity or fresh water, although expression of phosphate-hydrolyzing enzymes other than (Na⁺,K⁺)-ATPase was stimulated by high salinity acclimation.     

Effects of genistein in the maternal diet on reproductive development and spatial learning in male rats

Endocrine disruptors, chemicals that disturb the actions of endogenous hormones, have been implicated in birth defects associated with hormone-dependent development. Phytoestrogens are a class of endocrine disruptors found in plants. In the current study we examined the effects of exposure at various perinatal time periods to genistein, a soy phytoestrogen, on reproductive development and learning in male rats. Dams were fed genistein-containing (5 mg/kg feed) food during both gestation and lactation, during gestation only, during lactation only, or during neither period. Measures of reproductive development and body mass were taken in the male offspring during postnatal development, and learning and memory performance was assessed in adulthood. Genistein exposure via the maternal diet decreased body mass in the male offspring of dams fed genistein during both gestation and lactation, during lactation only, but not during gestation only. Genistein decreased anogenital distance when exposure was during both gestation and lactation, but there was no effect when exposure was limited to one of these time periods. Similarly, spatial learning in the Morris water maze was impaired in male rats exposed to genistein during both gestation and lactation, but not in rats exposed during only one of these time periods. There was no effect of genistein on cued or contextual fear conditioning. In summary, the data indicate that exposure to genistein through the maternal diet significantly impacts growth in male offspring if exposure is during lactation. The effects of genistein on reproductive development and spatial learning required exposure throughout the pre- and postnatal periods.     

Regulation of store-operated Ca entry in pulmonary artery smooth muscle cells

Store-operated Ca²⁺ entry (SOCE) is an important mechanism for Ca²⁺ influx in smooth muscle cells; however the activation and regulation of this influx pathway are incompletely understood. In the present study we have examined the effect of several protein kinases in regulating SOCE in pulmonary artery smooth muscle cells (PASMCs) of the rat. Inhibition of protein kinase C with chelerythrine (3 μM) potentiated SOCE by 47 ± 2%, while the tyrosine kinase inhibitors genistein (100 μM) and tyrphostin 23 (100 μM) caused a significant reduction in SOCE of 55 ± 9% and 43 ± 7%, respectively. It has been proposed that Ca²⁺-insensitive phospholipase A₂ (iPLA₂) is involved in the activation of SOCE in many different cell types. The iPLA₂ inhibitor, bromoenol lactone had no effect on SOCE, suggesting that this mechanism was not involved in the activation of the pathway. The calmodulin antagonists, calmidazolium (CMZ) (10 μM) and W-7 (10 μM) appeared to potentiate SOCE in PASMCs. Further investigation established that CMZ was actually activating a Ca²⁺ influx pathway that was independent of the filling state of the sarcoplasmic reticulum. The CMZ-activated Ca²⁺ influx was blocked by Gd³⁺ (10 μM), but unaffected by 2-APB (75 μM), indicating a pharmacological profile distinct from the classical SOCE pathway.     

High-salt intake primes the rat kidney to respond to a subthreshold uroguanylin dose during ex vivo renal perfusion

In a variety of animal models, uroguanylin causes diuresis, natriuresis and kaliuresis and is found in larger concentrations in the urine compared to controls after oral salt intake or in conditions of excess salt and fluid retention. It has been proposed that uroguanylin functions as an intestinal natriuretic hormone following intake of meals high in salt content. In the present work, we examined if 10 days of salt ingestion resulted in an enhanced response to uroguanylin in the isolated perfused rat kidney. Rats were given normal water, 1% NaCl (HS1%), or 2% NaCl (HS2%) for 10 days, at which time the right kidneys were surgically removed and perfused with a modified Krebs-Henseleit solution for 30 min. After a 30-min control period, the kidneys were perfused with a modified Krebs-Henseleit solution containing 0.06 μM uroguanylin for an additional 90 min. Compared to vehicle-matched time controls, 0.06 μM uroguanylin perfusion of kidneys from rats maintained on HS2% resulted in a significantly increased urine flow (UF; from 0.17 ± 0.01 to 0.23 ± 0.01, after 60 min, n = 6, P < 0.05), fractional Na⁺ excretion (%E_Na+; from 16.6 ± 0.7 to 30 ± 2, after 60 min, n = 6, P < 0.05), fractional K⁺ excretion (%E_K+; from 20.5 ± 0.58 to 37.4 ± 2.1, after 60 min, n = 6, P < 0.05), and fractional Cl⁻ excretion increased from 18.16 ± 0.52 to 35.2 ± 2.0 at 60 min, n = 6, P < 0.05. With the exception of a significant increase in the %E_K+, no other effect was observed in the kidneys from the rats maintained on HS1%, and no significant effects were seen in those that were maintained on normal water. The effect of a higher dose (0.6 µM) of uroguanylin on urinary flow, sodium or potassium excretion was also significantly increased by 2% NaCl (HS2%) treatment (P < 0.05). We also observed an expressive upregulation of the GC-C and a slight downregulation of the GC-A receptor in high-salt treated rats. These data demonstrate that prolonged salt ingestion primes the kidney to enhanced renal responses to uroguanylin.     

Seasonal effects on circulating leptin in the lizard Sceloporus undulatus from two populations

Characterizing leptin's structure and function in mammals has been the subject of thousands of studies since 1994. Recently, the study of leptin has expanded to include its distribution in non-mammalian taxa, and the role that leptin plays in the reproductive axis. We demonstrated in a previous study that Sceloporus undulatus, fence lizards (ectotherms), express a leptin-like protein. In the current study we quantified seasonal variation in this putative leptin among free-ranging fence lizards from two populations characterized by early and late reproductive maturation (after one or two years, respectively). Immunoblots were performed on whole blood samples to detect leptin and estimate its titer. Leptin titers were higher in the reproductive population of S. undulatus (early maturing: 2.5 ± 0.2 μg/mL; late-maturing 2.2 ± 0.3 μg/mL; mean ± 2 S.E.), but both populations showed the same seasonal pattern. Leptin titers were lowest in fall when fat stores are expected to be highest (spring: 2.6 ± 0.3 μg/mL; summer: 2.6 ± 0.3; μg/mL; fall: 1.8 ± 0.3 μg/mL), consistent with findings of seasonal variation in free-ranging mammals. Our data support previous work asserting that lizards express leptin and that it has a similar physiological function in endotherms and ectotherms. Our long-term goal is to use leptin to manipulate age at maturity and to test fundamental questions in the evolution of life-history strategies.     

NF-κB inhibitory activity of cyclitols isolated from Hancornia speciosa

Hancornia speciosa Gomes (Apocynaceae) is a Brazilian plant traditionally employed to treat inflammatory conditions, among other uses. The chemopreventive effect of an ethanol extract from H. speciosa leaves (EHS) was evaluated in a battery of in vitro tests [inhibition of aromatase, NF-κB and ornithine decarboxylase (ODC), antioxidant response elements (ARE) induction and cell proliferation assays]. Bioassay-directed fractionation of EHS following by inhibition of 12-O-tetradecanoyl-13-acetate (TPA)-mediated NF-kB activation led to the isolation of the cyclitols quinic acid (1) (85.0±12.3 μM) and l-(+)-bornesitol (2) (IC₅₀=27.5±3.8 μM), along with rutin (26.8±6.3 μM). Based on these lead compounds, the cyclitols per-O-acetyl-1l-(+)-bornesitol (3) (IC₅₀=38.4±6.2 μM), myo-inositol (4) (>180.2 μM), scyllo-inositol (5) (83.0±13.7 μM) and β-d-galactoside-myo-inositol (6) (52.4±8.4 μM) were evaluated in the assay, but found to be somewhat less active than 1 and 2. None of the compounds was active in the ARE, aromatase or ODC assays and did not inhibit proliferation of MCF-7, LNCaP, HepG2 or LU-1 cell lines at a final concentration of 20 μg/ml (equivalent to 104.07–32.76 μM).This work identifies l-(+)-bornesitol, quinic acid and rutin as NF-κB inhibitors of H. speciosa and suggests cyclitols, in addition to myo-inositol, are potentially useful as chemopreventive agents.     

Comparison of two methods for calculating the frictional properties of articular cartilage using a simple pendulum and intact mouse knee joints

In attempts to better understand the etiology of osteoarthritis, a debilitating joint disease that results in the degeneration of articular cartilage (AC) in synovial joints, researchers have focused on joint tribology, the study of joint friction, lubrication, and wear. Several different approaches have been used to investigate the frictional properties of articular cartilage. In this study, we examined two analysis methods for calculating the coefficient of friction (μ) using a simple pendulum system and BL6 murine knee joints (n=10) as the fulcrum. A Stanton linear decay model (Lin μ) and an exponential model that accounts for viscous damping (Exp μ) were fit to the decaying pendulum oscillations. Root mean square error (RMSE), asymptotic standard error (ASE), and coefficient of variation (CV) were calculated to evaluate the fit and measurement precision of each model. This investigation demonstrated that while Lin μ was more repeatable, based on CV (5.0% for Lin μ; 18% for Exp μ), Exp μ provided a better fitting model, based on RMSE (0.165° for Exp μ; 0.391° for Lin μ) and ASE (0.033 for Exp μ; 0.185 for Lin μ), and had a significantly lower coefficient of friction value (0.022±0.007 for Exp μ; 0.042±0.016 for Lin μ) (p=0.001). This study details the use of a simple pendulum for examining cartilage properties in situ that will have applications investigating cartilage mechanics in a variety of species. The Exp μ model provided a more accurate fit to the experimental data for predicting the frictional properties of intact joints in pendulum systems.     

Effects of prolactin deficiency during the early postnatal period on the development of maternal behavior in female rats: Mother's milk makes the difference

During early life, prolactin (PRL) ingested by the pups through the milk participates in the development of neuroendocrine, immunological and reproductive systems. The present study tested whether a deficiency in PRL in the dam's milk during early lactation affected the offspring in terms of the maternal responsiveness in the sensitization paradigm and behavioral response to a novel environment in the offspring. Thus, lactating rats were injected (sc) on postnatal days (PND) 2–5 with bromocriptine (125 μg/day), bromocriptine + ovine PRL (125 μg + 300 μg/day), or vehicle. As juveniles (at PND 24) or adults (PND 90–100), one female from each litter was exposed to 5 foster pups continuously for 8 days and their maternal responsiveness was recorded. Female offspring were also tested in an open field arena. Adult, but not juvenile, female offspring of bromocriptine-treated mothers showed an increased latency to become maternal, in comparison to latencies displayed by the offspring of control mothers. Furthermore, the proportion of adult, but not juvenile, offspring of bromocriptine-treated mothers that became maternal was lower than that showed by the offspring of vehicle-treated mothers. In comparison to female offspring of vehicle-treated mothers, female offspring of bromocriptine-treated mothers spent less time hovering over the pups (as juvenile females), body licking (as both juvenile and adult females), and in close proximity to pups (as adult females) during the maternal behavior test. Simultaneous administration of ovine PRL and bromocriptine reversed almost all the negative effects of bromocriptine. These data suggest that maternally-derived PRL participates during the early postnatal period in the development of neural systems that underlie the control of maternal behavior.     

Epigenetic and phenotypic changes result from a continuous pre and post natal dietary exposure to phytoestrogens in an experimental population of mice

Background  

Developmental effects of exposure to endocrine disruptors can influence adult characters in mammals, but could also have evolutionary consequences. The aim of this study was to simulate an environmental exposure of an experimental population of mice to high amounts of nutritional phytoestrogens and to evaluate parameters of relevance for evolutionary change in the offspring. The effect of a continuous pre- and post-natal exposure to high levels of dietary isoflavones was evaluated on sexual maturity, morphometric parameters and DNA methylation status in mice. Adult mice male/female couples were fed ad libitum either with control diet (standard laboratory chow) or ISF diet (control diet plus a soy isoflavone extract at 2% (w/w) that contained the phytoestrogens genistein and daidzein). In the offspring we measured: i) the onset of vaginal opening (sexual maturation) in females, ii) weight and size in all pups at 7, 14, 21 and 42 days post-natal (dpn) and iii) DNA methylation patterns in skeletal α-actin (Acta1), estrogen receptor-α and c-fos in adults (42 dpn).     

The Determination of Phosphorus in Haemophilus influenzae Type b Conjugate Vaccines by Inductively Coupled Plasma-Atomic Emission Spectrometry

This study describes a method for the determination of phosphorus in lyophilized Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of polysaccharide is directly related to the concentration of phosphorus as measured in the laboratory. Phosphorus is present in the polyribosyl-ribitol phosphate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. The repeating unit of PRP is 3-B-D ribose[1-1]ribitol-5-phosphate. Phosphorus in the final container is measured in μ g per dose. The amount of PRP is calculated from this and reported in μ g per dose. The Haemophilus influenzae type b conjugate vaccine was analyzed for phosphorus content within the range of 1·34 to 2·02 μg phosphorus per ml. The relative difference of phosphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2·2 to 10·6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1·93±0·13 μ g P/ml). The phosphorus determination of NIST SRM 3139 phosphorus spectrometric solution differed by 3·0% from the certified phosphorus value (10·00 mg P/ml).