Dynamics of follicle populations and gonadotropin concentrations in fillies age two to ten months

Follicle populations and concentrations of circulating gonadotropins were studied during age 2-10 months in 10 spring-born pony fillies. Blood sampling and ultrasound scanning were done every 4 days and daily for four 30 day periods. During 5-12 weeks, FSH concentrations were lower in 6 fillies with follicles greater than or equal to 6 mm (mean +/- s.e. 1.4 +/- 0.1 ng/ml) than in 4 fillies with follicles <6 mm (2.8 + 0.3 ng/ml). The diameters and numbers of follicles and gonadotropin concentrations increased progressively during age 2-4 months. A plateau in follicle activity and reduced levels of gonadotropins occurred during 5-7 months. During 8-10 months, follicles grew to >10 mm and gonadotropin concentrations increased. Waves of follicular growth were identified during the 30 day periods by significant increases in the diameter of the 10 largest follicles. The waves did not partition into dominant and subordinate follicles. Results indicated an initial postnatal period of negative ovarian feedback, temporally related changes in gonadotropins and follicles for months 3-10, and development of follicles in waves.

POSSIBLE MECHANISMS FOR REDUCTION OF CIRCULATING CONCENTRATIONS OF PROGESTERONE BY INTERFERON-ALPHA IN COWS - EFFECTS ON HYPERTHERMIA, LUTEAL CELLS, METABOLISM OF PROGESTERONE AND SECRETION OF LH

Experiments were performed to determine the mechanism by which recombinant bovine interferon-alpha(I)1 (rbIFN-alpha) causes an acute reduction in plasma concentrations of progesterone. In experiment 1, administration of a prostaglandin synthesis inhibitor blocked rbIFN-alpha-induced hyperthermia but did not prevent the decline in plasma concentrations of progesterone. The decline in progesterone concentrations caused by rbIFN-alpha was, therefore, not a direct consequence of the associated hyperthermia or of pathways mediated through prostaglandin synthesis. It is also unlikely that rbIFN-alpha acts to increase the clearance of progesterone since injection of rbIFN-alpha did not decrease plasma concentrations of progesterone in ovariectomized cows given an intravaginal implant of progesterone (experiment 2). In experiment 3, rbIFN-alpha did not affect basal and LH-induced release of progesterone from cultured luteal slices, indicating that rbIFN-alpha is unlikely to affect luteal function directly. Injection of rbIFN-alpha did, however, cause a decrease in plasma concentrations of LH in ovariectomized cows (experiment 4) that coincided temporally with the decrease in progesterone concentrations seen in cows having a functional corpus luteum. The present results strongly suggest that rbIFN-alpha acts to reduce secretion of progesterone by interfering with pituitary support for luteal synthesis of progesterone. The finding that rbIFN-alpha can inhibit LH secretion implies that interferon-alpha molecules should be considered among the cytokines that can regulate hypothalamic or pituitary function.

Influence of two methods of CaCl2 application and concentrations used to maintain passion fruit firmness

This is a report on the influence of the methods of postharvest application of CaCl2 in several concentrations, on the maintenance of the firmness of the sweet passion fruit (Passiflora alata Dryander). The fruits, picked in the pre-climateric stage, were selected desinfection with thiabendazol and submitted to CaCl2 in concentrations of 0% (control), 1%, 2%, 3% or 4% with two methods: immersion (for 2 h) and infiltration under vacuum and pressure (- 25 vacuum kPa, for 1 minute and, + 25 pressure kPa, for 1 min). All fruits were stored under refrigeration (9 degreesC, 85-90% RH), for 30 d. The fruits were evaluated for texture every 3 d. From the results, it is concluded that application of CaCl2 by infiltration favored the maintenance of fruit consistency during the first 18 days of storage. Fruits treated with 1% and 2% of CaCl2 were firmer than the others.

Study of the alkaline earth metals with 8-hydroxyquinolinate derivatives - Calcium complexes

Metal complexes of calcium with 5,7-dibromo, 7-iodo and 5-chloro-7-iodo-8-hydroxyquinolate were precipitated in aqueous ammonia and acetone medium, except for the solid state compound with 5,7-dichloro-8-hydroxyquinoline which hasn't been obtained under these conditions. The complexes obtained through the mentioned precipitation are Ca[(C9H4ONBr2)(2)](3).H2O, Ca[(C9H5ONI)(2)].2H(2)O and Ca[(C9H4ONICl)(2)].2.5H(2)O. Their intermediate from the thermal decomposition found through TG/DTA curves in air indicated the presence of different kinds of calcium carbonates related to the reversibility and crystalline structure, depending on the original compounds. The initial compounds and the intermediate from the thermal decomposition were also characterized through IR spectra and X-ray diffraction.

Air-drying of fresh and osmotically pre-treated pineapple slices: Fixed air temperature versus fixed slice temperature drying kinetics

In this investigation, the air drying characteristics of fresh and osmotically pre-treated pineapple slices in a tray dryer were studied under different operating conditions. The air velocity varied from 1.5 to 2.5 m/s and the air temperature from 40 to 70 degreesC. The analytical solution of the second Fick's law for an infinite slab was used to calculate effective diffusion coefficients and their temperature dependence could be well represented by an Arrhenius-type equation. Comparison of the results showed that the diffusion coefficients were lower for the pre-treated fruit. By means of automatic control, it was possible to obtain drying curves under conditions of constant product temperature, which showed to be an alternative to reduce the drying time of pineapple slices.

Influence of Sources and Meteorology on Surface Concentrations of Gases and Aerosols in a Coastal Industrial Complex

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Minimum inhibitory concentrations of Staphylococcus aureus recovered from clinical and subclinical cases of bovine mastitis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Site-specific concentrations of carotenoids in adipose tissue: relations with dietary and serum carotenoid concentrations in healthy adults

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and thermal study of 8-hydroxy-quinoline derivatives of the alkaline Earth metals: I. Strontium complexes

Strontium complexes of 5,7-dibromo-, 5,7-dichloro-, 7-iodo- and 5-chloro-7-iodo-8-hydroxyquinoline were precipitated from an aqueous ammonia and acetone medium. The complexes obtained were Sr[(C9H4ONBr2)2]·2.5H 2O; Sr[(C9H4ONCl2)(OH)]·1.5H2O; Sr[(C9H5ONI)2]·5H2O and Sr[(C9H4ONICl)(OH)]·1.25H2O. The residues of their thermal decomposition were SrBr2; a mixture of SrCl2, SrCO3 and SrO3 SrCO3, and SrCO3, respectively. All were characterized by means of thermogravimetry, differential thermal analysis, complexometry with EDTA, atomic absorption spectroscopy, IR spectroscopy and X-ray diffraction. © 1999 Akadémiai Kiadó.

Influence of antimicrobial subinhibitory concentrations on hemolytic activity and bacteriocin-like substances in oral: Fusobacterium nucleatum

Fusobacterium nucleatum is considered for its role in colonization of initial and late microorganisms in dental plaque and for its coaggregation with other bacterial species. It is known that action of different antimicrobial substances may interfere with either virulence factors or with host-bacteria interaction. The goal of this study was to examine the influence of subinhibitory concentrations of chlorhexidine, triclosan , penicillin G and metronidazole on hemolytic activity and bacteriocin-like substance production of oral F. nucleatum. A high resistance to penicillin G was observed and 63% of the isolates were β-lactamase positive. All the tested isolates were susceptible to metronidazole. F. nucleatum isolates grown with or without antimicrobials were alpha-hemolytics. Bacteriocin-like substance production was increased in isolates grown with penicillin G. Impaired production of hemolytic or antagonic substances can suggest a role in the regulation of oral microbiota.

Interfacial concentrations of chloride and bromide and selectivity for ion exchange in vesicles prepared with dioctadecyldimethylammonium halides, lipids, and their mixtures

The local concentrations of chloride, Cl b, and bromide, Br b, in the interface of vesicles prepared with dioctadecyldimethylammonium chloride, DODAC, or bromide, DODAB, dipalmitoylphosphatidylcholine, DPPC, dimyristoylphosphatidylcholine, DMPC, and mixtures of DMPC, DPPC, and DODAC were determined by chemical trapping by analyzing product yields from spontaneous dediazoniation of vesicle-bound 2,6-dimethyl-4-hexadecylbenzenediazonium ion. The values of Cl b and Br b in DODAC and DODAB vesicles increase with vesicle size, in agreement with previous data showing that counterion dissociation decreases with vesicle size. Addition of tetramethylammonium chloride displaces bromide from the DODAB vesicular interface. The value for the selectivity constant for Br/Cl exchange at the DODAB vesicular interface obtained by chemical trapping was ∼2.0, well within values obtained for comparable amphiphiles. In vesicles of DPPC the values of Cl b were very sensitive to the nature of the cation and decreased in the order Ca 2+ > Mg 2+ > Li + > Na + > K + = Cs + = Rb + ≥ +. The effect of the cation becomes more important as temperature increases above the phase transition temperature, T m, of the lipid. The values of Cl b increased sigmoidally with the mol % of DODAC in vesicles prepared with DODAC/lipid mixtures. In sonicated vesicles prepared with DODAC and DMPC (or DPPC), the values of Cl b reach local concentrations measured for the pure amphiphile at 80 mol % DODAC. These results represent the first extensive study of local concentration of ions determined directly by chemical trapping in vesicles prepared with lipids, synthetic ampliiphiles, and their mixtures.

Larval development of the giant river prawn Macrobrachium rosenbergii at different ammonia concentrations and pH values

The effect of ammonia and pH levels on giant river prawn Macrobrachium rosenbergii larvae were evaluated to provide science-based information on safe levels of ammonia and pH for larviculture. Survival rate, developmental stage, and larval weight gain were determined for larvae kept in water with total ammonia (NH4-N) concentrations of 0, 1, 2, 4, and 8 mg\L and pH 7, 8, and 9. The trials were conducted in two phases: phase 1, larvae from stages I through VIII and phase 2, larvae from stage VIII until metamorphose. Oxygen consumption was determined for larvae in stages I and VIII at total ammonia concentrations of 0, 4, and 8 mg/L and pH 8. Survival rate up to stage VIII varied from 86 to 98% and did not differ for total ammonia concentrations in pH 7 and 8 and for 0 mg/L NH4-N in pH 9. Survival rate was significantly lower (0-20%) for total ammonia concentrations from 1 to 8 mg/L (0.43-3.41 mg/L of unionized ammonia) in pH 9. Larval stage indexes (7.9-8.0 range) and weight gain (1.572-2.931 mg range) of larvae at the end of phase 1 of the experiment did not differ for the different ammonia concentration solutions, but were significantly lower in pH 9. In phase 2, no parameter differed among treatments for pH 7 and 8; however there was total mortality at pH 9 until 96h. Respiration rates diminished when larvae were exposed to total ammonia concentrations of 4 and 8 mg/L (0.28 and 0.55 mg/L of unionized ammonia), but development remained unaltered. Therefore, M. rosenbergii larvae tolerate high levels of total ammonia, while toxicity depends primarily on unionized ammonia concentrations. In addition, alkaline pH (9) acted directly on the larvae, curbing development and causing severe mortality. Larval tolerance to high ammonia and pH levels decreases for the last zoeal stages. © Copyright by the World Aquaculture Society 2005.