Different thermal sensitivity to exercise and cold in men and women

Rectal temperature gain for sweating and shivering was investigated in men (M) and women during exercise and cold exposure. Women, taking and not taking oral contraceptives, were tested during follicular (F) and luteal (L) phases of the menstrual cycle. The gains for sweating (M, 4.85; F, 5.00; L, 12.25 kPa °C⁻¹) and shivering (M, 6.50; F, 2.75; L, 2.00 ml kg min⁻¹ °C⁻¹) differed between sexes, as well as between F and L, and were affected by the oral contraceptives (5.45 and 8.00 kPa °C⁻¹, P<0.01, and 6.00 and 4.25 ml kg min⁻¹ °C⁻¹, P<0.05, respectively).     

Epigenetic regulation of bone morphogenetic protein-6 gene expression in breast cancer cells

Bone morphogenetic protein-6 (BMP-6) is closely correlated with tumor differentiation and skeletal metastasis. Our previous research found that BMP-6 gene expression can be activated dose-dependently by estrogen in estrogen receptor positive (ER⁺) breast cancer cell line MCF-7, but not in ER negative (ER⁻) cell line MDA-MB-231. This experiment is designed to investigate the epigenetic regulatory mechanism of the BMP-6 gene expression in breast cancer cell lines MDA-MB-231, MCF-7 and T47D with regard to the methylation status in the 5′ flanking region of the human BMP-6 gene. The endogenous level of BMP-6 mRNA in ER⁻ cell line MDA-MB-231 was relatively lower than that in ER⁺ MCF-7 and T47D cell lines. After the treatment with 5-aza-2′-deoxycytidine (5-aza-dC, especially in the concentration of 10 μM), the BMP-6 mRNA expression in MDA-MB-231 was obviously up-regulated. However, 5-aza-dC treatment failed to regulate the expression of BMP-6 in MCF-7 and T47D cells. Using enzyme restriction PCR (MSRE-PCR), as well as bisulfite sequencing (BSG), methylation of human BMP-6 gene promoter was detected in MDA-MB-231; while in MCF-7 and T47D, BMP-6 gene promoter remained demethylated status. In 33 breast tumor specimens, promoter methylation of BMP-6 was detected by methylation-specific PCR, hypermethylation of BMP-6 was observed in ER negative cases (16 of 16 cases (100%)), while obviously lower methylation frequency were observed in ER positive cases (3 of 17 cases (18%)), indicating that BMP-6 promoter methylation status is correlated with ER status in breast cancer.     

Effects of season on the yield and quality of agar from Gracilaria species (Gracilariaceae, Rhodophyta)

The effect of season on yield and physical properties of agars extracted from Gracia gracilis and G. bursa-pastoris were determined. The agar yield from G. gracilis was maximum during spring (30%) and minimum during autumn (19%). In G. bursa-pastoris, the agar yield was greatest in summer (36%) and lowest in winter (23%). Agar yield from G. bursa-pastoris was positively correlated with temperature (r=0.94; P<0.01) and salinity (r=0.97; P<0.01) and negatively with nitrogen content (r=−0.93; P<0.01). Agar gel strengths fluctuated from 229 to 828 g cm⁻² and 23 to 168 g cm⁻² for G. gracilis and G. bursa-pastoris, respectively. The gelling temperature showed significant seasonal variation for both species. Chemical analysis of agar from the two seaweeds indicated variation in 3,6-anhydrogalactose and sulfate content (P<0.01). Furthermore, there was an inverse correlation between the two chemical variables. In general, agar extracted from G. gracilis possessed better qualities than agar extracted from G. bursa-pastoris and can be considered a candidate for industrial use.     

Effects of time and dietary iron on tissue iron concentration as an estimate of relative bioavailability of supplemental iron sources for ruminants

Two experiments were conducted to investigate the effects of time and dietary Fe on tissue Fe concentrations following short-term, high level supplementation for use as a bioassay procedure for supplemental Fe sources for ruminants. In Experiment 1, 28 wethers were allotted randomly to four experimental diets which were fed for 15 or 30 days. The basal maize–soyabean meal–cottonseed hulls diet (193 mg kg⁻¹ Fe) was supplemented with 0, 400, 800 or1200 mg kg⁻¹ added Fe from reagent grade ferrous sulfate (FeSO₄·7H₂O). Iron concentrations in liver, kidney, and spleen increased (P<0.05) as dietary Fe increased; however, muscle, heart, and bone Fe concentrations were unaffected. A logarithmic transformation of liver or kidney Fe concentrations at 30 days regressed on added dietary Fe produced the best fits to a linear model. In Experiment 2, bioavailability of Fe from three feed grade ferrous carbonates known to differ (carbonates A, B, and C) was compared to that from reagent grade ferrous sulfate. The dietary treatments fed for 30 days included the above basal diet (90 mg kg⁻¹ Fe) supplemented with 0, 300, 600 or 900 mg kg⁻¹ added Fe from ferrous sulfate or 600 mg kg⁻¹ Fe from ferrous carbonates A, B, or C. Liver Fe concentrations from sheep fed ferrous sulfate were numerically greater than those of animals fed the carbonate sources or control diet. Kidney Fe concentrations from lambs fed ferrous sulfate at 600 mg kg⁻¹ Fe or carbonate-A were greater (P<0.05) than those fed carbonates B or C. Iron concentrations in spleen were lower (P<0.05) in lambs fed carbonate-B than for those fed 600 mg kg⁻¹ Fe as ferrous sulfate, but were similar to other carbonates. Overall average bioavailability estimates based on multiple regression slope ratios for the three tissues were ferrous sulfate 1.00, carbonate-A 0.55, carbonate-B 0.00, and carbonate-C 0.20. Estimates for carbonates A and C were similar to those based on hemoglobin concentrations reported previously for young swine supplemented at dietary concentrations near the requirement.     

Optical outer-sphere charge transfer in aqueous ion pairs with sulfidic anions as donors

Various sulfidic anions and the oxidizing cations [Ru(NH₃)₆]³⁺ and N,N′-dimethyl-4,4′-bipyridinium²⁺ (paraquat²⁺) form ion pairs in aqueous solutions which display outer-sphere charge-transfer (CT) absorptions. The CT energies are used to establish a series of sulfidic anions with increasing CT donor strength: SCN⁻2O₃ ²⁻4 ³⁻3S³⁻2 ⁻2S₂ ⁻4 ²⁻.     

Calcium ion control of platelet thrombosthenin ATPase activity

This study demonstrates that Ca²⁺ regulates thrombosthenin ATPase activity, likening the control of platelet contraction to that of cardiac and skeletal muscle. Thrombosthenin, the platelet contractile protein, was isolated by repeated low ionic strength and isoelectric precipitation. Thrombosthenin superprecipitation and ATPase activity were measured in 10⁻⁴ M CaCl₂ (high ionized Ca²⁺) and 0.25 mM ethylene glycol bis-(β-aminoethyl ether)-N,N′-tetraacetic acid (EGTA) (low ionized Ca²⁺). In both high and low Ca²⁺, superprecipitation, measured as an increase in turbidity, ocurred shortly after addition of ATP. ATP hydrolysis by thrombosthenin, which proceeded linearly for several hours, was greater in high Ca²⁺ (approx. 2.3 nmoles·mg⁻¹·min⁻¹) than in low Ca²⁺ (approx. 1.8 nmoles·mg⁻¹·min⁻¹). This difference, when analyzed by the Student's t-test for paired samples was highly significant (P < 0.001). Thrombosthenin ATPase activity was not significantly altered by azide, an inhibitor of mitochondrial ATPase, nor by ouabain, an inhibitor of (Na⁺ + K⁺)-activated ATPase. The dependence of thrombosthenin activation on ionized Ca²⁺, measured with the use of CaEGTA buffers, was studied. The Ca²⁺-dependent portion of thrombosthenin ATPase was half maximal at 4.5·10⁻⁷ M Ca²⁺. This corresponds to an apparent binding constant of 2.2·10⁶ M⁻¹, a value that is comparable to that of skeletal and cardiac muscle. These data suggest that a Ca²⁺ control mechanism similar to that of the troponin-tropomyosin complex of muscle exists in the platelet.     

Interrelationships between two-dimensional phase diagrams and mean molecular area-mole fraction curves in mixed monolayers

Both two-dimensional phase diagrams and mean molecular area (A)—mole fraction(x₂^π) curves have been investigated for various types of mixed monolayer systems. Two-dimensional phase diagram analysis and the behavior of A−x₂^π curves were found to be in good agreement with each other. From this result it was concluded that we should consider both phase diagrams and A−x₂^π curves of a mixed monolayer system in order to understand the behavior of the A−x₂^π curves.     

Effects of oilseed meal and grain-urea supplements fed infrequently on digestion in sheep: 1. Low quality grass hay diets

An experiment examined intake, growth response and rumen digestion of young sheep fed ad libitum low quality grass hay alone or supplemented with approximately isonitrogenous amounts of barley grain and urea (Bar/N), safflower meal (SAF) or linseed meal (LIN) provided at 3 days intervals. Supplements comprised 13–20% of total DM intake. Sheep fed grass hay alone consumed 60.2 g DM/kg LW^0.75/day of hay and an estimated 6.09 MJ metabolizable energy (ME)/day, and were in liveweight (LW) maintenance. Hay intake was decreased (P<0.05) by the Bar/N supplement with a substitution rate of 0.9, but was not changed by the oilseed meal supplements. Each of the supplements increased (P<0.05) estimated ME intake to a similar extent, but LW gain and wool growth were lower (P<0.05) in sheep supplemented with Bar/N than those supplemented with LIN. Rumen degradabilities of the SAF and LIN CP were estimated to be 0.72 and 0.62, respectively. Rumen ammonia concentrations in sheep fed hay alone (average 97 mg NH₃/l) were expected to be adequate for microbial activity. Fractional outflow rate (FOR) of liquid from the rumen measured with Co-EDTA (mean 0.109 h⁻¹) was greater than that of Cr-mordanted supplements (mean 0.056 h⁻¹), which was in turn greater than the FOR of Cr-mordanted hay (mean 0.031 h⁻¹). Diet did not affect these FOR. Supplemented sheep accommodated increased DM intake on Day 1 of the 3 day supplementation cycle by increasing rumen digesta load rather than by increasing rate of passage of digesta. Results show that the LW gain of young sheep fed low quality hay was increased more by either oilseed meal than by equivalent amounts of barley grain/urea supplement, apparently due to more efficient utilization of ME for LW gain.     

Adrenomedullin stimulates somatostatin and thus inhibits histamine and acid secretion in the fundus of the stomach

Adrenomedullin has recently been localized to enterochromaffin-like (ECL) and chief cells in the gastric fundus. It has been proposed that adrenomedullin may play a role in gastric mucosal defense and repair. In the present study, we have used the isolated, luminally perfused mouse stomach and superfused rat fundic segments to examine the effect of adrenomedullin on exocrine and endocrine secretion in this region of the stomach.

Addition of adrenomedullin (1 pM to 1 μM) to the isolated mouse stomach caused a concentration-dependent decrease in acid secretion. The EC₅₀ value was 1.4×10⁻⁹ and maximal inhibition of acid secretion was obtained at a concentration of 1 μM (31±4% below basal level, P<0.001). In rat fundic segments, superfusion with adrenomedullin (0.1 pM to 0.1 μM) caused a concentration-dependent increase in somatostatin secretion (EC₅₀, 1×10⁻¹⁰) that was accompanied by a reciprocal decrease in histamine secretion (EC₅₀, 1.2×10⁻¹¹). Maximal stimulation of somatostatin secretion (60±5% above basal level, P<0.001) and inhibition of histamine secretion (50±5% below basal level, P<0.01) was obtained at a concentration of 0.1 μM. Changes in acid and histamine secretion induced by adrenomedullin reflected changes in somatostatin secretion and could be abolished by addition of somatostatin antibody. The axonal blocker, tetrodotoxin, also abolished the somatostatin and, consequently, the acid and histamine responses to adrenomedullin, implying that the effect of adrenomedullin on somatostatin secretion was mediated via activation of intramural neurons.

We conclude that adrenomedullin, acting via intramural fundic neurons, stimulates somatostatin and thus inhibits histamine and acid secretion. This represents one mechanism by which adrenomedullin might enhance mucosal defense and repair.     

Effects of environmental factors, age and genotype on sperm production and semen quality in Bos indicus and Bos taurus AI bulls in Brazil

The effects of ambient temperature and humidity, month, age and genotype on sperm production and semen quality in AI bulls in Brazil were evaluated. Data from two consecutive years were analyzed separately. Seven Bos indicus and 11 Bos taurus bulls from one artificial insemination (AI) center were evaluated in Year 1 and 24 B. indicus and 16 B. taurus bulls from three AI centers were evaluated in Year 2. Ambient temperature and humidity did not significantly affect sperm production and semen quality, probably because there was little variation in these variables. Month accounted for less than 2% of the variation in sperm production and semen quality. Increased bull age was associated with decreased sperm motility (P<0.10) and increased minor sperm defects (P<0.001) in Year 1. B. indicus bulls had greater (P<0.005) sperm concentration than B. taurus bulls in both years (1.7×10⁹/ml versus 1.2×10⁹/ml in Year 1 and 1.6×10⁹/ml versus 1.2×10⁹/ml in Year 2, respectively). Ejaculate volume was not significantly affected by genotype in Year 1 (6.6 ml versus 6.9 ml in B. indicus and B. taurus bulls, respectively), but B. indicus bulls had greater (P<0.05) total (11.4×10⁹ versus 8.2×10⁹) and viable (6.7×10⁹ versus 4.9×10⁹) numbers of spermatozoa in the ejaculate than B. taurus bulls. In Year 2, B. taurus bulls had greater (P<0.05) ejaculate volume than B. indicus bulls (8.2 ml versus 6.7 ml, respectively) and total and viable number of spermatozoa in the ejaculate were not significantly different between genotypes (10.3×10⁹ versus 9.1×10⁹ and 6.1×10⁹ versus 5.4×10⁹ in B. indicus and B. taurus bulls, respectively). Sperm motility was not significantly affected by genotype (mean, 59%). In Year 1, B. indicus bulls tended (P<0.10) to have more major sperm defects and had more (P<0.05) total sperm defects than B. taurus bulls (11.8% versus 8.7% and 13.6% versus 10.0%, respectively). In Year 2, B. indicus bulls tended (P<0.10) to have more total sperm defects than B. taurus bulls (16.2% versus 13.3%, respectively). In conclusion, neither ambient temperature and humidity nor month (season) significantly affected sperm production and semen quality. B. indicus bulls had significantly greater sperm concentration and B. taurus bulls had significantly fewer morphologically defective spermatozoa.     

Modifications in the aggressive and ingestive behavior of the neonatal piglet as a result of prenatal elevation of cortisol in the dam

Ninety-eight piglets from 10 sows were used to study their neonatal agonistic and ingestive behavior after stimulation of the preparturient sow with adrenocorticotrophic hormone (ACTH). The sows were randomly assigned to either an ACTH or a control group on the 104th day of gestation. Sows in the ACTH group were catheterized and infused with 1IU porcine ACTH kg⁻¹ day⁻¹ in 1 l of saline. Control sows were similarly catheterized and infused with the same volume of saline, both treatments being maintained until parturition. A blood sample was collected daily from all sows. At birth piglets were weighed, bled and freed in the rear of the farrowing crate. They were then observed for the first 6 h of life to record their birth to suckle (BTS) interval. At the same time all instigator and victim interactions were recorded. Three subsequent blood samples were then collected from the piglets at 2, 4 and 6 h of life, and analyzed for glucose and cortisol. In both groups the concentration of plasma cortisol proved to be decreased (P<0.05) after birth while glucose increased within 2 h. The total number of instigations observed was higher (P<0.05) in pigs born to control sows than in those born to ACTH-treated sows. When values were expressed as instigations per pig or number of instigations relative to the total number of possible interactions within the litter, piglets of the ACTH group also exhibited less (P<0.05) aggressive instigations than those born to the control sows. Victimizations were not influenced either by treatment or sex. ACTH pigs had slightly shorter BTS intervals (P<0.05) than those in the control group. Females were lighter (P<0.05) than males at birth but they took less time to suckle than males. Accordingly it is concluded that the prenatal treatment of the sows with ACTH reduces the rate of agonistic interactions and tends to reduce the time required for first-time successful suckling.     

Association between estradiol, estrogen receptors, total lipids, triglycerides, and cholesterol in patients with benign and malignant breast tumors

This study addresses the correlation between the levels of estradiol (E₂), total lipids, triglycerides, and cholesterol in serum and tissue samples of age-matched patients with benign (40 cases; 16 were premenopausal and 24 were postmenopausal) and malignant (50 cases; 17 were premenopausal and 33 were postmenopausal) breast tumors. Estradiol levels were determined in serum and cytosol, estrogen receptors (ER) were assayed in cytosol, and total lipids, triglycerides and cholesterol were determined in serum and membrane fractions of all benign and malignant breast disease patients. Serum E₂ was significantly higher in malignant cases than benign ones (P<0.05) with a significant reduction (40%) in postmenopausal than premenopausal women. ER-positive tumors were significantly higher in postmenopausal women with malignant breast tumors than benign cases (P<0.05). Tissue levels of total lipids, triglycerides, and cholesterol were highly significantly increased in breast cancer women than women with benign breast diseases (P<0.05, P<0.005 and P<0.05 respectively) and they were also significantly correlated with estradiol levels. It could be concluded that the uptake of lipids from plasma by the tumor tissue is greatly correlated to estradiol and it may confirm the possible role of lipids as risk factor in breast cancer.     

Binding of divalent copper and calcium ions to poly I

The effect ot Cu²⁺ and Ca²⁺ ions, on the ultraviolet differential (UVD) spectra of single-stranded poly I was studied and the coordination (Δε_b) and conformation (Δε_c) conponents of the spectra calculated The comparison of Δε_b and the UVD spectrum of protonated IMP leads to the conclusion that N(7) ot inosine-5'-monophosphate (IMP) is a coordinating site tor Ca²⁺ and Cu²⁺ ions on the polymer bases. The binding ot Ca²⁺ and Cu²⁺ ions causes differently directed displacements of the four absorption bands of poly I, which are observed in the wavenumber range (50-34) × 10³ cm⁻¹ The calculation of concentration dependencies tor the association constants (K“) ot Ca²⁺ and Cu²⁺ ions binding to poly I bases shows that the binding is cooperative The K“ values for the poly I + Ca²⁺ complex are two orders of magnitude lower than those for the poly 1 + Cu²⁺ complex At low ion concentrations, binding to the poly I phosphates predominates and increases the degree of the polynucleotide helicity. At higher concentrations the spectra are mainly affected by the ion binding to bases, which results in melting of the helical parts of poly I At Ca²⁺ concentrations exceeding 10⁻³ M light-scattering aggregates are formed. The degree of monomer order in them is close to that observed in multistranded helices of poly I     

Biological and clinical aspects of prolactin receptors (PRL-R) in human breast cancer

PRL has a definite activity in the induction and promotion of mouse and in the growth of rat mammary tumors. We and others have found that human PRL or growth hormone (GH) had a growth promoting effect on human mammary cancer cells. It has been shown that prolactin receptors (PRL-R) which are specific for all lactogenic hormones (hPRL, hGH, hPL) are present on mammary cancer cells in long-term tissue culture and also in tumor biopsies. We found that 43% of the tumors had free PRL-R (FPRL-R) and that 72% had total PRL-R (TPRL-R) which have been desaturated in vitro. A significant correlation (Spearman test) was found between PRL-R (especially TPRL-R) on the one hand, estradiol (P<0.001) and progesterone receptors (P<0.01) on the other. The demonstration of PRL-induced proteins (PIP) might be a better sign of PRL sensitivity than the existence or PRL-R; PIP have been found by Northern blot analysis in 47% of 70 breast cancers. Overall survival (OS) and relapse-free survival (RFS) analysis with a median duration of follow-up of 5.3 yr showed that TPRL-R had a significant prognostic value only in node positive patients (χ²=5.61, P=0.02). Neither FPRL-R or TPRL-R were a significant prognostic factor when studied by Cox analysis. This confirms our previous results. Since at least some human mammary cancers appear to be PRL-dependent we carried out a multicenter randomized trial comparing as the first hormonal treatment tamoxifen (TAM) (30 mg/day)+bromocriptin (B) (5 mg/day) vs TAM + placebo. 171 patients entered this trial. No difference was observed between the two groups in response rates, duration of response or survival.

Recent studies are thus in favor of a role of lactogenic hormones during the course of breast cancer. However no improvement in therapy has been observed yet. The combination of drugs to achieve a total anti-lactogenic treatment, the use of anti-PRL-R antibodies are interesting areas of research; the recent cloning of PRL-R and GH receptors may open new clinical perspectives.     

Efficiency of utilization of high and low quality forage by three goat breeds

Alpine, Angora and Nubian kids, 6–8 months old and weighing 15–25 kg were grazed on high quality (wheat) or low quality pasture (dormant bermudagrass) for 54 d to evaluate breed differences and metabolic responses. Each kid on the bermudagrass pasture also received daily 200 g of a 24% CP supplement to stimulate intake.

Wheat pasture had an in vitro organic matter digestibility (IVOMD) of 78 vs. 35% for the Bermuda pasture. Goats gained 50 g/d on wheat pasture vs. 10 g/d on Bermuda pasture (P<0.02). Angora kids gained the least weight on Bermuda (−8 g/d; P<0.05) and most on wheat pasture (62 g/d; P<0.05). Mohair production was greater for Angora goats on wheat pasture compared to those on Bermuda pastures (9.9 vs. 6.2 g/100 cm²; P<0.05). Angora goats on Bermuda pastures had elevated levels of NEFA and plasma ammonia, and reduced levels of plasma urea N, consistent with catabolism of body tissue stores. Angora goats tended to have lower concentration of rumen VFA and ammonia. Angora goats appear to be more sensitive to inanition as compared to Alpine and Nubian goats. Presumably, their obligate nutrient requirements for hair production limits their ability to adapt, making them more vulnerable to nutritional stress.     

The effects of barley, unmolassed sugar-beet pulp and molasses supplements on organic matter, nitrogen and fibre digestion in the rumen of cattle given a silage diet

In a 4 × 4 Latin-square experiment with a 2 × 2 factorial arrangement of treatments, 4 cattle fitted with a rumen and duodenal cannula were given four grass-containing diets [480 g kg⁻¹ of the total dry matter (DM) intake] and barley (BU), barley + molasses (2:1) (BM), sugar-beet pulp (SU) or sugar-beet pulp + molasses (SM). Duodenal flow was estimated using Cr-mordanted straw and CoEDTA as markers, and microbial nitrogen entering the small intestine using purine bases of nucleic acids.

Molasses-containing diets had a higher (P < 0.01) organic matter (OM) digestibility. The proportion of digestible OM apparently disappearing in the rumen averaged 0.72 and was not significantly affected by the diet. When cattle received molasses, the quantity of microbial N entering the small intestine was higher (P < 0.05) and there was a trend towards a higher efficiency of microbial N synthesis (28.8 vs. 25.6 g N kg⁻¹ OM apparently digested in the rumen). When S diets were consumed, total non-ammonia N flow at the duodenum exceeded N intake by 7.0 g day⁻¹ and when B diets were consumed, it was 0.7 g day⁻¹ less than N intake. Feed N degradability in the rumen and apparent N digestibility of S diets were lower (P < 0.05; P < 0.001) than those of B diets.

Rumen (P < 0.05) and total (P < 0.001) digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) was higher when S diets were given. The proportion of digestible fibre disappearing in the rumen was not affected by the diet. The rate and extent of silage and hay DM degradation were not significantly affected by the diet. However, dietary inclusion of molasses decreased (P < 0.05) the lag time of both hay and silage DM degradation.

The rumen dilution rate of liquid averaged 0.097 and that of particles, 0.049; neither was significantly different for either B and S diets or U and M diets. Duodenal liquid flow was higher (P < 0.05) for M diets.

Average rumen pH was not affected by the diet, but the molasses diets increased (P < 0.05) the range in rumen pH. The BM diet was associated with higher (P < 0.01) rumen ammonia concentration than the other diets. Low rumen ammonia concentrations (< 2 mM) were observed for long periods between feeds. The molar proportion of butyrate was higher on B diets and there was a trend towards a higher proportion of acetate and propionate on S diets. Molasses tended to increase the molar proportion of propionate and butyrate.     

Coincident increases in oxytocin receptor expression and EMG responsiveness to oxytocin in the ovine cervix at oestrus

This study has localised oxytocin receptor (OTR) mRNA expression within the cervix of non-pregnant ewes and related this to changes in the sensitivity of the cervical musculature to administered oxytocin (OT) during the oestrous cycle by recording electromyographic (EMG) activity. Cervices were collected from 34 ewes at specified time points throughout the cycle. OTR mRNA expression was localised by in situ hybridisation and results were expressed as optical density measurements from autoradiographs in each of four different cervical regions. EMG recordings were made for up to 8 h per day from four non-pregnant ewes undergoing seasonal oestrous cycles between Days −3 and +3 relative to oestrus (Day 0). The highest concentrations of OTR mRNA were detectable within the luminal epithelium (LE) of the cervix, with values increasing from Day 15 of the cycle, peaking during the follicular phase (P<0.001, compared to the mid-luteal phase) and returning to basal by Day 2. There was a small but significant increase in OTR mRNA hybridisation (above basal/luteal phase values) within the stromal cells (STR) adjacent to the lumen (P<0.05) during the same time period, but no differences from basal values were detectable in the dense collagenous annular ring or in tissue superficial to this. Analysis of pooled EMG activity recorded daily from the cervix indicated that endogenous contractile activity was higher on Day 0 than on the Days +1 (P<0.05), −2, +2 and +3 (P<0.001). The response to bolus intravenous (i.v.) injections of 25 mU OT (25 mU) varied with day of the cycle. This dose produced a measurable and significant response on Days 0 (P<0.001) and +1 (P<0.001), but not on any of the other days, indicating that the sensitivity of the cervical musculature to OT peaked on these days. These data show that the cervix is highly responsive to OT at oestrus. This coincides with an increase in OTR mRNA expression in the luminal epithelial cells, suggesting the likely production of an intermediary messenger between the epithelial and smooth muscle cells.     

Early changes in adenosine A1 receptors in cerebral cortex slices submitted to in vitro ischemia.

The effects of brain ischemia on the maximum binding capacity (B_max) and affinity (K_d) of A₁ receptors were studied in the rat cerebral cortex, with an in vitro approach. The results were correlated with changes in ³H-adenosine release, studied under identical experimental conditions. Fifteen minutes of in vitro ‘ischemia’ (hypoxic, glucose-free medium) induced a significant increase in both B_max (2398±132 fmol/mg protein, 151% of the control, P<0.05) and in K_d (2.43±0.12 nM, 161% of the control, P<0.01). At the same time, an increase in tritium efflux from [³H]-adenosine labeled cerebral cortex slices to 324% of the control was observed. A trend toward normalization was evident 5–15 min after ‘reoxygenation’ (restoring normal medium), but the binding parameters were still altered after 60 min (B_max 2110±82 fmol/mg protein, K_d 2.26±0.14 nM, P<0.01 vs the corresponding control) as was adenosine release (196% of the control). These findings suggest that the increased availability of adenosine and its receptors may be a defense mechanism against ischemic injury, while the reduced affinity of A₁ receptors, possibly due to desensitization, may be a sign of ischemia-induced cellular damage.     

Gemfibrozil treatment is associated with elevated adrenal androgen, androstanediol glucuronide and cortisol levels in dyslipidemic men

We have investigated the role of steroid hormones as coronary risk factors in Helsinki Heart Study population of dyslipidemic middle-aged men. We compare here the effects of gemfibrozil and placebo on the serum levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), their metabolite androstanediol glucuronide (3-AdiolG), androstenedione, cortisol, testosterone, and sex-hormone binding globulin (SHBG) in non-smokers. We also examined the associations between steroid and lipoprotein levels in both treatment groups. Compared with placebo gemfibrozil treatment was associated with significant elevations of the mean levels of DHEA 10.2 vs 8.0 nmol/1; P<0.005, of DHEAS 8.0 vs 5.8 μmol/1; P<0.001, of 3AdiolG 18.3 vs 8.4 nmol/1; P<0.001, of androstenedione 5.7 vs 5.1 nmol/1; P<0.02, and of cortisol 426 vs 358 nmol/1; P<0.001. The mean SHBG levels decreased from 46.4 to 41.7 nmol/1; P=0.03 with gemfibrozil treatment. No difference was found in testosterone levels 17.7 vs 18.8 nmol/1; P=0.11, or the ratio of testosterone/SHBG 0.45 vs 0.43; P=0.23. Positive correlations were found between high density lipoprotein-cholesterol and DHEAS (r=0.267; P<0.01) and DHEA (r=0.282; P<0.01) levels and negative correlations between low density lipoprotein-cholesterol and 3-AdiolG (r=−0.400; P<0.001) and cortisol (r=−0.281; P<0.01) levels in the gemfibozil group. Our results indicate that gemfibrozil treatment increases the production and turnover of adrenal androgens and cortisol, and suggest that activation of the adrenocorticol function and increased metabolism of androgens are related to the improved lipoprotein pattern during gemfibrozil treatment.     

Relationship between cyprid energy reserves and metamorphosis in the barnacle Balanus amphitrite Darwin (Cirripedia; Thoracica)

Nauplii batch cultures of Balanus amphitrite were reared with four different diatoms (Skeletonema costatum, Thalassiosira pseudonana, Chaetoceros gracilis, silicate-limited C. gracilis) at three different cells concentrations: 1×10⁵, 5×10⁵, and 1×10⁶ cells ml⁻¹. The cyprid energy reserves were quantified as the ratio of triacylglycerols (TAG) to DNA. Energy reserves of larvae fed on different diatoms at a concentration of 1×10⁶ cells ml⁻¹ were ranked in the order: silicate-limited C. gracilis>C. gracilis>T. pseudonana>S. costatum. There was a significant linear relationship between the TAG content of the diet and cyprid energy reserves. The effect of cyprid energy reserves on metamorphosis to polystyrene surface in the presence and the absence of conspecific settlement factor (SF) was studied after 12, 24, and 48 h of incubation. A strong positive correlation between energy reserves and percent metamorphosis was observed in the absence of SF (r_{12 h}=0.88, r_{24 h}=0.82, r_{48 h}=0.68, P<0.05). A weak positive correlation was observed in the presence of SF (r_{12 h}=0.43, r_{24 h}=0.48, r_{48 h}=0.50, P<0.05). In both treatments, more than 80% of the cyprids with high energy reserves metamorphosed within 24 h. In contrast, a high proportion of cyprids with low energy reserves metamorphosed in response to SF in 24 h. Our results indicate that discriminatory metamorphic behavior of cyprids is closely linked to their TAG/DNA ratio, a proxy for energy reserve.