Oestrous sheep serum balances ROS levels to supply in vitro capacitation of ram spermatozoa

Reactive oxygen species (ROS) are fundamental for intracellular signalling. In spermatozoa, they are involved both to apoptosis and to capacitation, and changes in ROS levels can alter the balance between these two processes. Oestrous sheep serum (OSS) is considered an efficient agent for in vitro capacitation of ram spermatozoa. We have explored the effects of OSS on ram sperm physiology, especially on ROS production, during in vitro capacitation. Semen samples from 15 rams were cryopreserved. After thawing, samples were submitted to four treatments: control (CTL), 10% OSS supplementation for in vitro sperm capacitation, caspase inhibitor (INH, Z‐VAD‐FMK 100 μM) and OSS (10%) plus caspase inhibitor (I + E). Sperm samples were incubated for 30 min at 38.5°C and 5% CO₂ and evaluated motility and kinetic parameters by computer‐assisted semen analysis (CASA) and viability (propidium iodide), apoptotic‐like membrane changes (YO‐PRO‐1), acrosomal status (PNA‐FITC), intracellular calcium (FLUO‐3), membrane fluidity (M540) and ROS production (CM‐H₂DCFDA) by flow cytometry. OSS induced changes in kinetic parameters compatible with capacitation, with a decrease in the percentage of progressive motility and linearity, and an increase in the amplitude of the lateral displacement of the sperm head (p < .05). Moreover, OSS increased the proportion of M540+ viable spermatozoa, YO‐PRO‐1+ and acrosome‐reacted spermatozoa (p < .05). After incubation, OSS and I+E achieved lower ROS levels (p < .05). Ca²⁺ levels did not change with the incubation, but were slightly higher (p < .05) when both OSS and the inhibitor were present. We suggest that OSS may modulate ROS levels, allowing intracellular signalling for capacitation to occur while preventing higher levels that could trigger apoptosis.     

Impact of disaggregation of composite foods on estimates of intakes of meat and meat products in Irish adults

OBJECTIVE: To evaluate the impact of the disaggregation of composite foods on intake estimates of meat and individual meat categories and on the contribution of meat to nutrient intakes in Irish adults. DESIGN: Data were analysed from the North/South Ireland Food Consumption Survey, which used a 7-day food diary to estimate food intake. Of 742 food codes that contained meat, 320 were codes for meat consumed as an individual portion and 422 were composite foods and were disaggregated to estimate the meat content. SUBJECTS: A nationally representative sample of 475 men and 483 women (not pregnant or lactating) from the Republic of Ireland aged 18-64 years. RESULTS: The mean intake of meat was 134 g day(-1) in consumers (98.5%) and men (168 g day(-1)) consumed significantly more (P<0.001) than women (102 g day(-1)). Mean intakes of meat were higher in subjects with manual skilled occupations (P<0.01) and lower in those with third-level educational qualifications (P<0.05). Without disaggregating meat from composite foods, meat intake was overestimated by 43% (57 g day(-1)) and varied widely by meat category. Meat disaggregated from composite foods contributed 25% of meat intake. The contribution meat made to nutrient intakes ranged from 29% for protein, vitamin B12, zinc and niacin to 20% for vitamin D, 16% for vitamin B6, 15% for thiamine and 14% for iron. CONCLUSIONS: Failure to disaggregate meat from composite foods substantially overestimates meat intake, with a large variation between meat categories. This has important implications for estimates of meat intakes in nutritional epidemiological studies and for food safety purposes.     

Vitamin D status of 51-75-year-old Irish women: its determinants and impact on biochemical indices of bone turnover

OBJECTIVES: To assess the vitamin D status of Irish postmenopausal women during wintertime, and to examine its relationship with serum parathyroid hormone (PTH) and biochemical markers of bone turnover. In addition, the determinants of wintertime serum 25-hydroxyvitamin D (25OH-D) levels in these women were investigated. DESIGN: A cross-sectional observational study. SETTING: Cork City, Ireland (52 degrees N). SUBJECTS: Ninety-five apparently healthy, free-living postmenopausal women (aged 51-75 years), not taking any medication and free from any condition likely to affect vitamin D status or calcium/bone metabolism. RESULTS: Forty-eight per cent and 7% of women had serum 25OH-D levels <50 nmol l(-1) and <25 nmol l(-1), respectively. 25OH-D levels in these women were positively associated with dietary calcium intake (P = 0.0002) and use of vitamin D-containing supplements (P = 0.031), and negatively associated with cigarette smoking (P = 0.027) and body mass index (BMI) (P = 0.030). Low serum 25OH-D levels (<50 nmol l(-1)) were associated (P < 0.01) with elevated serum PTH levels. There were no significant differences in urinary pyridinium crosslinks or serum osteocalcin, biochemical indices of bone turnover, between subjects with serum 25OH-D levels above or below 50 nmol l(-1). CONCLUSION: A high proportion of Irish postmenopausal women had low vitamin D status (<50 nmol l(-1)) during late wintertime, which appeared to lead to elevated levels of serum PTH but not of bone turnover markers. Use of regular low-dose supplemental vitamin D, meeting daily calcium recommendations, cessation of smoking and maintaining BMI in the normal range are important factors that could help maintain adequate vitamin D levels during wintertime in these women.     

Modulation of T-cell reactivity to synthetic peptide analogues of foot-and-mouth disease virus in sheep by amino acid substitutions.

The ability of synthetic peptide analogues of foot-and-mouth disease virus VP1 capsid protein to induce T-cell proliferation in vitro following immunization of sheep with the uncoupled peptides was assessed. Elevated T-cell responses were obtained to a 21-residue peptide containing VP1 residues 141-158, and a 40-residue peptide containing residues 200-213 and 141-158 linked via a diproline-serine spacer. In contrast, no significant T-cell response was obtained with a 19-residue peptide containing residues 200-213 alone. In an attempt to engineer T-cell reactivity to this peptide, a sequence motif found in many peptides recognized by human or mouse T-cells was introduced by amino acid substitution. Substitution of a glycine or an aspartic acid for an alanine at position 207 in the 19-residue peptide resulted in the introduction of two such motifs running consecutively. Immunization of sheep with these peptides resulted in significant T-cell proliferative responses and elevated antibody responses. Analysis of further sequence variants showed that T-cell responsiveness was maintained with peptides containing single amino acid changes within these motifs, provided position 207 was glycine. The results thus suggest that increased T-cell reactivity, might be engineered via sequence manipulation of the 200-213 component of the 40-residue synthetic peptide. Such an additional T-cell epitope in the 40-residue peptide could potentially result in superior neutralizing antibody responses directed against the major epitope in residues 141-160 of VP1.     

Evaluation of ameroid ring constrictors for treatment for single extrahepatic portosystemic shunts in dogs: 168 cases (1995-2001)

OBJECTIVES: To evaluate use of an ameroid ring constrictor (ARC) for treatment for single extrahepatic portosystemic shunts (PSSs) and identify factors associated with postoperative death, continued portosystemic shunting, and long-term outcome in dogs. DESIGN: Retrospective study. ANIMALS: 168 dogs with a single extrahepatic PSS. PROCEDURE: Medical records of dogs that had a single extrahepatic PSS and were treated with an ARC were reviewed. Signalment, history, clinical signs, results of preoperative blood analyses and portal pressure measurements, PSS location, ARC size, postoperative complications, and postoperative scintigraphy results were recorded. Owners were interviewed 6 months to 6 years after surgery. Results-Postoperative complications developed in 10% of dogs. Postoperative mortality rate was 7.1%. Predictive factors for postoperative death included high preoperative WBC count and postoperative complications. Twenty-one percent of dogs in which portal scintigraphy was performed 6 to 10 weeks after surgery had continued shunting. Predictive factors for persistent shunting included low preoperative plasma albumin concentration, high portal pressure after complete occlusion, and high portal pressure difference (postocclusion minus baseline). Clinical outcome in 108 dogs was classified as excellent (80%), good (14%), or poor (6%). Predictive factors for excellent long-term clinical outcome included high preoperative plasma albumin concentration, low preoperative leukocytosis, low portal pressure after complete occlusion, absence of postoperative seizures, and absence of continued shunting. CONCLUSIONS AND CLINICAL RELEVANCE: Use of an ARC for treatment for a single extrahepatic PSS resulted in low morbidity and mortality rates. Certain preoperative factors were associated with increased risk of postoperative death, continued portosystemic shunting, and long-term outcome.     

Control of sensory fields by stimulation of hypothalamus

Stimulation of the cat's hypothalamus, which elicits attack, also establishes sensory fields for two reflexes related to biting. Touching a perioral region leads to head movement, bringing the stimulus to the mouth. Touching the lip-line leads to jaw opening. The size of the fields depends on the intensity of stimulation.     

Generating electricity while walking with loads

We have developed the suspended-load backpack, which converts mechanical energy from the vertical movement of carried loads (weighing 20 to 38 kilograms) to electricity during normal walking [generating up to 7.4 watts, or a 300-fold increase over previous shoe devices (20 milliwatts)]. Unexpectedly, little extra metabolic energy (as compared to that expended carrying a rigid backpack) is required during electricity generation. This is probably due to a compensatory change in gait or loading regime, which reduces the metabolic power required for walking. This electricity generation can help give field scientists, explorers, and disaster-relief workers freedom from the heavy weight of replacement batteries and thereby extend their ability to operate in remote areas.