The effect of TiO(2) on the microstructural and electrical properties of low voltage varistor based on (Sn,Ti)O(2) ceramics

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)

Reliability of carnitine concentrations measured in single postprandial urine samples from dogs

Objective - To evaluate the reliability of urine carnitine concentrations measured in single postprandial samples, compared with carnitine concentrations measured in 24-hour urine samples. Animals - 19 healthy Beagles. Procedure - After emptying the urinary bladder by catheterization, dogs were fed a canned canine maintenance diet. Approximately 8 hours later, urine, plasma, and serum samples were obtained for determination of urinary carnitine fractional excretion and urine carnitine-to-creatinine concentration ratio. Results were compared with 24-hour urinary carnitine excretion rate. Results - Fractional excretion of carnitine and urine carnitine-to-creatinine ratios correlated poorly with 24-hour urinary carnitine excretion. Conclusion - Determination of 24-hour urinary carnitine excretion is recommended to measure urine carnitine concentrations in dogs.

Short communication longitudinal variation in the concentrations of C, N and P in the stem of Echinochloa polystachya (H.B.K.) Hitchcock

The Concentrations of C, N and P were determined in the internodes of the stem of Echinochloa polystachya (H.B.K.) Hitchcock with the aim of showing their longitudinal distributions. The concentrations ranged from 421.93 to 466.03 mgCgDW-1; from 2.78 to 13.61 mg N gDW-1 and from 0.151 to 1.074 mg P gDW-1. N and P concentrations increased towards the apical direction of the stem. C concentrations showed an inverse trend. These distributions suggest that N and P are transported to the apical region of the stem, while the majority of the C compounds observed in the distal region must be retained in the supporting structure of the plant.

Correlation between carotenoid concentrations in serum and normal breast adipose tissue of women with benign breast tumor or breast cancer

To evaluate the relationship between carotenoid concentrations in serum and breast tissue, we measured serum carotenoid concentrations and endogenous carotenoid levels in breast adipose tissue of women with benign breast tumor (n = 46) or breast cancer (n = 44). Before extraction, serum was digested with lipase and cholesterol esterase, and breast adipose tissue was saponified. Serum and tissue carotenoids were extracted with ether/hexane and measured by using HPLC with a C30 column. Serum retinoic acid was extracted with chloroform/methanol and measured using HPLC with a C18 column. There were no significant differences in serum carotenoids [lutein, zeaxanthin, cryptoxanthin (both α- and β-), α-carotene, all-trans β-carotene, 13-cis β-carotene and lycopene], retinoids (retinol, all-trans and 13-cis retinoic acids), and α- and -γ- tocopherol concentrations between benign breast tumor patients and breast cancer patients. A substantial amount of 9-cis β- carotene was present in adipose tissue and was the only carotenoid that had a significantly lower level in benign breast tumor patients than in breast cancer patients. Correlations between carotenoid concentrations in serum and in breast adipose tissue were determined by combining the data of the two groups. Concentrations of the major serum carotenoids except cryptoxanthin showed significant correlations with breast adipose tissue carotenoid levels. When the concentrations of serum carotenoids were adjusted for serum triglycerides or LDL, correlations between serum carotenoid concentrations and breast adipose tissue carotenoid levels markedly increased, including that of cryptoxanthin (P <0.001). The strong correlation between serum carotenoid concentrations and endogenous breast adipose tissue carotenoid levels indicate that dietary intake influences adipose tissue carotenoid levels as well as serum concentrations, and that adipose tissue is a dynamic reservoir of fat-soluble nutrients.

Endogenous carotenoid concentrations in cancerous and non-cancerous tissues of gastric cancer patients in Korea

Carotenoid concentrations were measured in serum and in both non-cancerous and cancerous gastric mucosal tissues of Korean patients with gastric cancer (n = 18). Carotenoids in serum and gastric tissue were extracted with chloroform/methanol (2:1), and measured using reverse-phase high-performance liquid chromatography with a C30 column. Cryptoxanthin and β-carotene were the major carotenoids in the Korean blood and they had a median ratio of non-cancerous tissue/serum levels which was less than 1.0. No significant differences of Cryptoxanthin and β-carotene levels were found between non-cancerous and cancerous tissues. After incubation of β-carotene with gastric tissue, significantly higher levels of β-carotene breakdown products were produced in the homogenates of cancerous tissue when compared with non-cancerous tissue. Lutein, zeaxanthin and α-carotene were the minor carotenoid constituents in the blood and their median ratio of non-cancerous tissue/serum levels was greater than 1.0. Cancerous tissue had significantly lower levels of lutein, zeaxanthin and α-carotene than did non-cancerous tissue. It appears that the increased breakdown of β-carotene and cryptoxanthin in cancerous tissue can be compensated for by an increased uptake of circulating carotenoids by cancerous tissue, whereas lutein, zeaxanthin and α-carotene levels in cancerous tissue are not able to be maintained.

Role of luteinizing hormone in follicle deviation based on manipulating progesterone concentrations in mares

The effects of several doses of progesterone on FSH and LH concentrations were used to study the role of the gonadotropins on deviation in growth rates of the two largest follicles during the establishment of follicle dominance. Progesterone was given to pony mares at a daily dose rate of 0 mg (controls), 30 mg (low dose), 100 mg (intermediate dose), and 300 mg (high dose). All follicles ≥ 6 mm were ablated at Day 10 (Day 0 = ovulation) to initiate a new follicular wave; prostaglandin F(2α) was given to induce luteolysis, and progesterone was given from Days 10 to 24. The low dose did not significantly alter any of the ovarian or gonadotropin end points. The high dose reduced (P < 0.05) the ablation-induced FSH concentrations on Day 11. Maximum diameter of the largest follicle (17.2 ± 0.6 mm) and the second- largest follicle (15.5 ± 0.9 mm) in the high-dose group was less (P < 0.04) than the diameter of the second-largest follicle in the controls (20.0 ± 1.0 mm) at the beginning of deviation (Day 16.7 ± 0.4). Thus, the growth of the two largest follicles was reduced by the high dose, presumably through depression of FSH, so that the follicles did not attain a diameter characteristic of deviation in the controls. The intermediate dose did not affect FSH concentrations. However, the LH concentrations increased in the control, low, and intermediate groups, but then decreased (P < 0.05) in the intermediate group to pretreatment levels. The LH decrease in the intermediate group occurred 2 days before deviation in the controls. The maximum diameter of the largest follicle was less (P < 0.0001) in the intermediate group (27.3 ± 1.8 mm) than in the controls (38.9 ± 1.5 mm), but the maximum diameter of the second-largest follicle was not different between the two groups (19.0 ± 1.1 vs. 20.3 ± 1.0 mm). Thus, the onset of deviation, as assessed by the second-largest follicle, was not delayed by the decrease in LH. Diameter of the largest follicle by Day 18 in the intermediate group (23.1 ± 1.6 mm) was less (P < 0.05) than in the controls (28.0 ± 1.0 mm). These results suggest that circulating LH was not involved in the initiation of dominance (inhibition of other follicles by the largest follicle) but was required for the continued growth of the largest follicle after or concurrently with its initial expression of dominance.

Temporal interrelationships among luteolysis, FSH and LH concentrations and follicle deviation in mares

The effect of altered LH concentrations on the deviation in growth rates between the 2 largest follicles was studied in pony mares. The progestational phase was shortened by administration of PGF2α on Day 10 (Day 0=ovulation; n=9) or lengthened by daily administration of 100 mg of progesterone on Days 10 to 30 (n=11; controls, n=10). All follicles ≥5 mm were ablated on Day 10 in all groups to initiate a new follicular wave. The interovulatory interval was not altered by the PGF2α treatment despite a 4-day earlier decrease in progesterone concentrations. Time required for growth of the follicles of the new wave apparently delayed the interval to ovulation after luteolysis. The FSH concentrations of the first post-ablation FSH surge were not different among groups. A second FSH surge with an associated follicular wave began by Day 22 in 7 of 11 mares in the progesterone group and in 0 of 19 mares in the other groups, indicating reduced functional competence of the largest follicle. A prolonged elevation in LH concentrations began on the mean day of wave emergence (Day 11) in the prostaglandin group (19.2 ± 2.2 vs 9.0 ± 0.7 ng/mL in controls; P<0.05), an average of 4 d before an increase in the controls. Concentrations of LH in the progesterone group initially increased until Day 14 and then decreased so that by Day 18 the concentrations were lower (P<0.05) than in the control group (12.9 ± 1.6 vs 20.2 ± 2.6 ng/mL). Neither the early and prolonged increase nor the early decrease in LH concentrations altered the growth profile of the second-largest follicle, suggesting that LH was not involved in the initiation of deviation. However, the early decrease in LH concentrations in the progesterone group was followed by a smaller (P<0.05) diameter of the largest follicle by Day 20 (26.9 ± 1.7 mm) than the controls (30.3 ± 1.7 mm), suggesting that LH was necessary for continued growth of the largest follicle after deviation. (C) 2000 by Elsevier B.V.

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.

Effect of powder milling and dopant addition on the current-voltage characteristics of SnO2-based ceramics

Non-linear electrical properties of SnO2-based ceramics were investigated as a function of powder agglomeration condition and as a function of dopant addition. All doped powders presented a single phase, cassiterite, as evidenced by X-ray diffraction analysis. The effect of milling was quite evident, with non-milled powder showing higher agglomerated particle size than milled powder. Cr addition seemed to increase the non-linear coefficient. Cu and Mn rendered dense ceramics, but α values for systems with Mn were higher than for systems with Cu.

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.

Acute reduction in serum progesterone concentrations after feed intake in dairy cows

This study tested the hypothesis that high feed consumption will acutely decrease circulating progesterone concentrations. In the first experiment, a Latin Square design was used to test whether feeding pattern would alter circulating progesterone in pregnant lactating Holstein cows (n = 12). Feed was removed for 12 h before the experiment and cows were then either fed 100% of the total mixed ration (TMR), 50% of TMR every 12 h, 25% of TMR every 6 h, or left unfed for an additional 12 h. Blood samples were taken every hour for 24 h. Provision of 100 or 50% of TMR decreased circulating progesterone by 1 h after feeding and progesterone remained depressed until 8-9 h after feeding. Feeding 25% of TMR did not reduce circulating progesterone concentrations. Experiment 2 used a crossover design to measure the effect of acute feeding on circulating progesterone and LH concentrations during delivery of a constant amount of exogenous progesterone (Eazi-Breed CIDRs) in lactating Holstein cows (n = 8) and nonpregnant dry Holstein cows (n = 6). Blood samples were taken every 15 min for 8 h. There was no change in serum progesterone during the 8 h treatment period in unfed cows; however, feeding decreased (P < 0.05) circulating progesterone between 2 and 6 h after feeding. In lactating cows, feeding increased mean LH (P < 0.05). There were more LH pulses (P = 0.01) in lactating than nonlactating cows. Thus, acute feeding reduced circulating progesterone in pregnant lactating cows apparently due to an increase in progesterone metabolism. Interestingly, feeding multiple smaller meals eliminated the acute effect of feeding on circulating progesterone. © 2003 Published by Elsevier B.V.

Changes in norepinephrine and epinephrine concentrations in adrenal gland of the rats submitted to acute immobilization stress

Catecholamines act as neurotransmitters and hormones. Studies conducted to understand the synthesis and metabolism of these monoamines during stress have been the main concern of many authors. This work proposes to investigate the time course of changes in epinephrine and norepinephrine concentration in adrenal gland obtained from rats submitted to acute immobilization stress. The results of the present study indicate that acute immobilization stress during 5 and 15min did not provoke changes in epinephrine and norepinephrine concentrations in adrenal gland in relation to the control group. Such results are justified due to the short time of the stress, showing that the stress did not provoke physiological alteration. The epinephrine and norepinephrine concentrations in adrenal gland increased significantly after the immobilization session in stressed groups during 30 and 50min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In this way, we suggested that the immobilization stress provoke increase in the biosynthesis of catecholamines in the adrenal gland from rats. However, the results shows that a maximum increase is reached at 30min of immobilization stress and then a decrement of catecholamines levels starts at 50min of the experimental design. This decline in catecholamines level may be consequence of adaptation to stress situations, an increase of the activity of the uptake systems and/or metabolization of catecholamines. In conclusion, these results suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions. © 2003 Elsevier Ltd. All rights reserved.