Effect of endocytic and metabolic inhibitors on the internalization and intracellular growth of Brucella abortus in Vero cells.

Uptake, transfer to rough endoplasmic reticulum, and intracellular growth of Brucella abortus were studied in Vero cells treated with endocytic and metabolic inhibitors. Infection of Vero cells was suppressed when inhibitors of energy metabolism (iodoacetate, dinitrophenol), receptor-mediated endocytosis (monodansylcadaverine, amantadine, methylamine), or endosomal acidification (chloroquine, ammonium chloride, monensin) were added to the inoculum. Inhibition was not observed when these drugs were added after the inoculation period. Infection of Vero cells by B abortus was inhibited by dibutyryl-cyclic adenosine monophosphate and Vibrio cholerae enterotoxin, but was stimulated by dibutyryl-cyclic guanosine monophosphate and escherichia coli heat-stable enterotoxin a. Uptake of B abortus by Vero cells was not prevented by colchicine, but was abolished by cytochalasin B. Uptake of heat-killed B abortus and noninvasive E coli was similar to that of viable brucellae. Intracellular growth of B abortus was not affected by cycloheximide. Results indicate that: B abortus may be internalized by a receptor-mediated phagocytic process; transfer of B abortus from phagosomes to rough endoplasmic reticulum may require endosomal acidification; and replication of B abortus within the rough endoplasmic reticulum may not depend on protein synthesis by the host cell.     

Evaluation of an electronic device used as a quick screening method to detect changes in the red cell content of the blood in horses participating in endurance trail rides

Dehydration, to varying degrees, will inevitably occur in horses participating in endurance trail rides. This water loss is directly related to the amount of body water lost through evaporative cooling, that in turn being related to the amount and rate of work performed, and to the environmental temperature and humidity.An electronic apparatus that can substitute for the conventional and time-consuming venous haematocrit was developed to measure the animals' hydration status. The mechanism of this electrometer is based upon the relationship between the red cell content and the electrical conductivity of the blood. The electrometer reading gave a significant correlation (p<0.001) with the venous haematocrit, thus indicating that the electrometer is a reliable apparatus for determining the animals' hydration status within seconds of venepuncture.     

Pharmacokinetics of sulphadimidine in carp (Cyprinus carpio L.) and rainbow trout (Salmo gairdneri Richardson) acclimated at two different temperature levels

The influence of temperature (10 degrees C and 20 degrees C) on pharmacokinetics and metabolism of sulphadimidine (SDM) in carp and trout was studied. At 20 degrees C a significantly lower level of distribution (Vdarea) and a significantly shorter elimination half-life (T(1/2)beta) was achieved in both species compared to the 10 degrees C level. In carp the body clearance parameter (ClB(SDM)) was significantly higher at 20 degrees C compared to the value at 10 degrees C, whereas for trout this parameter was in the same order of magnitude for both temperatures. N4-acetylsulphadimidine (N4-SDM) was the main metabolite of SDM in both species at the two temperature levels. The relative N4-SDM plasma percentage in carp was significantly higher at 20 degrees C than at 10 degrees C, whereas there was in trout no significant difference. In neither species was the peak plasma concentration of N4-SDM (Cmax(N4-SDM)) significantly different at two temperatures. The corresponding peak time of this metabolite (Tmax(N4-SDM)) was significantly shorter at 20 degrees C compared to 10 degrees C in both carp and trout. In carp at both temperatures, acetylation occurs to a greater extent than hydroxylation. Only the 6-hydroxymethyl-metabolite (SCH2OH) was detected in carp, at a significant different level at the two temperatures. Concentrations of hydroxy metabolites in trout were at the detection level of the HPLC-method (0.02-micrograms/ml). The glucuronide metabolite (SOH-gluc.) was not detected in either species at the two temperatures.     

Effects of thromboxane synthetase inhibition on immune complex glomerulonephritis.

To determine the role of thromboxane A2 in the pathogenesis of experimentally induced immune complex glomerulonephritis, 12 concanavalin A-immunized Beagles were infused with 1 mg of concanavalin A via each renal artery and treated twice daily for 8 days with either 30 mg of CGS 12970/kg, PO, a specific thromboxane synthetase inhibitor, or placebo. The effect of treatment was assessed by measuring endogenous creatinine clearance and urine protein and eicosanoid excretion, and by evaluating changes in glomerular morphometric characteristics. On postinfusion day 8, urine protein, thromboxane B2, and 11-dehydro-thromboxane B2 excretion, glomerular epithelial crescent formation, and glomerular cell proliferation in the CGS 12970-treated dogs were significantly decreased when compared with values in the placebo-treated group. Differences were not observed in endogenous creatinine clearance, urine prostaglandin E2 and 6-keto-prostaglandin F1 alpha excretion, or glomerular polymorphonuclear leukocyte infiltration between groups in this study. These findings suggest thromboxane A2 has a role in the development of immune complex glomerulonephritis and that thromboxane synthetase inhibition may be beneficial in attenuating some of the functional and histological changes associated with immune complex glomerulonephritis.     

Effect of short-term calf removal at three stages of a follicular wave on fate of a dominant follicle in postpartum beef cows.

The hypothesis that ovulation in response to short-term (48 h) calf removal (CR) is dependent on the developmental stage of the dominant follicle was tested in two studies. The objective of Exp. 1 was to characterize the fate of a dominant follicle following 48-h CR on d 2, 4, or 8 of a postpartum follicular wave. Ovaries of 61 beef cows were examined daily by transrectal ultrasonography starting at d 20 to 21 postpartum. Treatments were no CR (n = 14) and CR on d 2 (n = 12), 4 (n = 16), or 8 (n = 10) of first detected follicular wave. Percentage of cows that ovulated a dominant follicle following treatment was not different among groups (P = 0.62). Maximum size of dominant follicles was larger in cows that ovulated (P = 0.002) than in cows that did not ovulate. The objectives of Exp. 2 were 1) to determine whether a follicular wave could be synchronized in anestrous cows following injection of 1 mg of estradiol benzoate (EB) and 200 mg of progesterone (P4; EB + P4); 2) to characterize the fate of dominant follicles following 48-h CR at three stages of a synchronized follicular wave; and 3) to determine whether estrous cycles of normal length followed ovulation in cows pretreated with EB + P4. Ovaries of 50 anestrous beef cows were examined daily as in Exp. 1. Treatments were sesame oil (SO) injected (i.m.) on d 25 postpartum and no CR (n = 9); EB + P4 and no CR (n = 9); EB + P4 and CR on 6 (n = 12), 8 (n = 9), or 12 (n = 11) d after injection. The EB and P4 injections were given on d 25 postpartum. Variability in day of emergence of subsequent follicular waves was lower in cows receiving EB + P4 than in SO-injected cows (P < 0.05). The percentage of cows that ovulated was not different (P = 0.16), but CR increased the percentage of cows that ovulated when groups that received EB + P4 were compared to the EB + P4 group that did not have CR (53.1 vs 11.1%, respectively; P < 0.05). Maximum diameter of dominant follicles was larger (P = 0.05) in ovulatory follicles. The luteal phase was longer (P < 0.03) in cows receiving EB + P4 injection (10.6 +/- 1.2 d) than in cows receiving SO (4.4 +/- 2.2 d). In summary, the maximum size of ovulatory follicles was greater than that of nonovulatory follicles, the ovulatory response of postpartum anestrous cows was maintained through d 8 of a follicular wave, synchronization of follicular waves was accomplished in postpartum cows using EB + P4, and the subsequent luteal phase length was increased in animals that were administered EB + P4.     

Sources of error with in vitro digestibility assay of pasture feeds

A series of experiments was undertaken to determine population statistics for in vitro organic matter digestibility ( in vitro OMD) data and to examine the effects of basal diet, donor animal and precollection fasting interval on the activity and specificity of rumen fluid inoculum. The experiments utilized wether sheep, a diverse set of pasture grass and legume feeds prominent in the Australian subtropics and the Tilley and Terry in vitro digestibility procedure running under the operating pressure of a practicing feeds evaluation laboratory.
The standard errors of in vitro OMD estimates for within and between batch runs were ±0·88 × 10⁻² and 0·62 × 10⁻², respectively. These error terms were used to develop protocols to accept, reject or scale raw in vitro OMD data. Differences between donor animals in the activity of rumen fluid were highly significant. Extending the precollection fasting interval beyond 16 h was associated with a substantial decline in inoculum activity.
An in vitro-in vivo calibration relationship based on fifteen test feeds and using lucerne ( Medicago sativa ) as basal diet was described by the linear model y = 1·3 x-0·195±4·9 × 10⁻² r = 0·79 (y = in vivo OMD, x = in vitro OMD). Despite large effects of basal diet on both the absolute values and relative ranking of test feeds, neither the RSD nor r values were improved using alternative diets to Lucerne chaff.
The results highlight the need to formally standardize the analytical and biological components of the in vitro digestibility procedure to safeguard the integrity of data.     

Identification by isoelectric focusing of creatine kinase-MM isoforms in the plasma and striated muscle of pigs

Total creatine kinase (CK) and CK-MM isoforms were determined in plasma and longissimus dorsi muscle extracts from normal pigs. Based on their total CK activity, the pigs were divided into two groups. Pigs of group 1 (n=16) had a mean plasma total CK of 298±16 U/L and the distribution of the CK-MM isoforms was 65.7±2.5% CK-MM₃, 18.9±1.6% CK-MM₂ and 15.3±1.5% CK-MM. In group 2 (n=18; 826±75 U/L total CK) four isoforms were observed: 3.1±0.9% CK-MM, 67.9±3.0% CK-MM₃, 21.5±2.3% CK-MM₂ and 7.5±1.3% CK-MM₁. The differences between the two groups of pigs were significant (p<0.001) for CK-MM₁ and the presence of CK-MM. Four CK-MM isoforms were also detected in longissimus dorsi muscle homogenates: 45.6±8.1% CK-MM, 32.6±11.7% CK-MM₃, 16.6±2.3% CK-MM₂ and 5.1±2.8% CK-MM₁. The release of CK-MM isoforms from muscle into plasma seems to be unrelated to the concentration of these isoforms in striated muscle.     

Effects of monensin on Mg, Ca, P and Zn metabolism and tissue concentrations in lambs

A study consisting of two trials was conducted to determine the effects of monensin on the apparent absorption and retention of magnesium (Mg), phosphorus (P), calcium (Ca) and zinc (Zn) and to determine mineral changes in tissue and ruminal fluid. Eight lambs (39 kg) were used in trial 1, and 10 lambs (37 kg) were used in trial 2. Animals were blocked by weight and fed a high concentrate diet with or without 20 mg/kg monensin. Trials began with a dietary adjustment period lasting 18 d in trial 1 and 21 d in trial 2. Animals were then placed in metabolism stalls for a 10-d stall adjustment period followed by a 12-d collection period. Collections to determine mineral balance were made during the first 10 d of the collection period. Blood and ruminal fluid samples were taken on d 11 of the collection period. Lambs were slaughtered on d 12 of the collection period and tissue samples were collected. Monensin supplementation increased (P less than .05) Mg retention 42.0%. Urinary Ca excretion decreased (P less than .05) 60.0% when monensin was fed. Monensin supplementation decreased (P less than .05) liver Ca and bone Ca, 45.5 and 2.9%, respectively. Apparent P digestibility increased (P less than .05) 40.0% and P retention increased (P less than .10) 26.8% due to monensin supplementation. Both apparent absorption and retention of Zn increased (P less than .01) 50.0 and 45.0%, respectively, with monensin supplementation. Ruminal fluid Zn concentrations decreased (P less than .05) 33.0% with the addition of monensin.(ABSTRACT TRUNCATED AT 250 WORDS)     

山洪对房屋的破坏及防患

山洪对房屋的破坏随着生态环境的恶化而加剧,其损失又随人民生活水平的提高而增加。防患房屋遭受山洪破坏刻不容缓。本文客观地总结了山洪破坏房屋具有的区域性、多样性、毁灭性特征,通过分析房屋遭受山洪破坏的沉痼陋习,初步揭示了山洪惩罚人为性大失误的沉痛教训,进而提出防患山洪破坏房屋要非工程措施与工程措施相结合,运用社会、经济、法律的手段,加以减灾引导,加强建房管理,采取开撇水沟、挖水平槽、刨鱼鳞坑、砌护坡墙、打挡水桩等直接有效的工程措施,加速隐患补救,实现减灾目的。