A Prospective Study Of Intravenous Catheter Contamination

A one year prospective study was conducted to determine the association between intravenous catheter contamination and increased dwell time, and to identify any related risk factors. Intravenous catheters obtained from 23 cats and 98 dogs in the Intensive Care Unit at the Ontario Veterinary College with dwell times > 72 hours for the test group (n=58) and < 72 hours for a corresponding control group (n=63) were cultured between April 1991 and March 1992. One hundred and twenty one catheters were cultured, 16 jugular, 99 cephalic, and 6 saphenous. The overall contamination rate was 13 out of 121 catheters cultured (10.7%); 9/63 (14.3%) control and 4/58 (6.9%) test catheters. The bacteria isolated were E.aerogenes, S.aureus (3), P.aeruginosa, P.multocida, and Bacillus sp (7). The Bacillus sp positive catheters (5 control and 2 test) were placed during a five day period, and contaminated gauze squares were identified as the source of infection in these catheters. After these were removed from the study, the group infection rate was 6.9% control and 3.6% test. There was no significant difference between groups and no associated risk factors were identified. We conclude that intravenous dwell time need not be restricted to <72 hours.     

Involvement of high-density lipoprotein in stimulatory effect of hormones supporting function of the bovine corpus luteum

The hypothesis that epinephrine (noradrenaline, NA) enhances utilisation of high-density lipoproteins (HDL) by bovine luteal cells and that this process involves phospholipase (PL) C and protein kinase (PK) C intracellular pathway was tested. Luteal cells from days 2-4, 5-10 or 11-17 of the oestrous cycle were preincubated for 20 h. Subsequently DMEM/Ham's F-12 medium was replaced by fresh medium and the cells were treated for 6 h as follows: In Experiment I with HDL (5-75 micrograms cholesterol per ml), NA, isoprenaline (ISO) or luteinising hormone (LH). In Experiment II cells were incubated for further 24 h in deficient medium (without FCS) and next treated as in Experiment I. In Experiment III cells were stimulated with NA, ISO or LH alone and together with HDL. In Experiment IV cells were treated with PLC inhibitor (U-73122) or with PKC inhibitor (staurosporine) or stimulator (phorbol 12-myristrate 13-acetate) and with either NA, insulin or LH. Only luteal cells from days 5-10 of the cycle responded on HDL and beta-mimetics (P < 0.05). LH stimulated progesterone secretion from the luteal cells during all stages of the cycle (P < 0.001). Cells incubated in deficient medium and supplemented with HDL secreted as much progesterone as those stimulated by LH in all stages of the cycle. Beta-mimetics were unable to enhance the stimulatory effect of HDL. Blockade of PLC had no influence on progesterone secretion from cells treated with either NA or LH, but this did impair the stimulatory effect of insulin (P < 0.05). Similarly, blockade of PKC by staurosporine impaired (P < 0.05) the effect of insulin only but not that observed after LH or NA treatment. We suggest that: (a) noradrenergic stimulation does not enhance utilisation of cholesterol from HDL for progesterone secretion; (b) the fasting of luteal cells seems to activate enzymes responsible for the progesterone synthesis; (c) effect of NA on progesterone secretion from luteal cells does not involve the PLC-PKC pathway.     

Transportation of cattle.

Until recent years, relatively little attention has been given to beef cattle transportation management and research in the United States As oulined in this article, it is clear that there are significant physiologic changes occurring in cattle as a result of transport and handling. These physiologic changes encompass, among others, effects on immune system function, disease incidence, and carcass quality. Significant advancements have been made during the past decade in the use of appropriate cattle-handling techniques, facility design,and research promoting our understanding and the attenuation of transport stress. Many issues surrounding livestock transport, such as temperature and ventilation during transit, use of rest stops, pretransit feeding regimens, and incidence of disease transmission via transport vehicles, need further research to enable continued provision of science-based recommendations to the livestock and transportation industries.     

In vitro metabolism of ovarian steroids by bovine whole blood and plasma

Experiments were conducted to evaluate the effects of time and temperature on the potential of bovine whole blood (WB) or plasma (PL) to metabolize the ovarian steroids progesterone, estradiol-17β and testosterone. During a radioimmunoassay study (Experiment 1), we observed a temperature and time-dependent reduction (P<0.001) of plasma progesterone concentrations in samples incubated as WB at 5, 15, 25, or 35C for up to 48 hr. Most notable was the observation that 27% of progesterone present in controls was lost when WB was incubated at 5C for 48 hr and a 17% reduction was observed when PL samples were incubated at 35C for 48 hr. Immunoreactive estradiol-17β concentrations (Experiment 2) in PL and WB incubates were not affected by time or temperature. However, immunoreactive testosterone concentrations increased more than 3-fold by 48 hr in WB incubates held at 35C. To examine the latter observation further, ³H-progesteone was incubated with WB at 35C, followed by extraction and thin-layer chromatography (Experiment 3). Results generally supported RIA findings and revealed the presence of significant 17α-hydroxylase, 17–20 lyase and aromatase activity. Heretofore this has not been considered to occur outside major steroid metabolizing organs.     

High-speed steel tool wear during wood cutting in the presence of high-temperature corrosion and mineral contamination

Dulling of high-speed steel (HSS) cutting tools after milling five wood species has been analyzed. The wood investigated varied in mineral contamination, high-temperature corrosivity (HTC) and density (D). Experiments performed proved that up to date methods for evaluation of mineral contamination in wood should be improved. A new pipe-like form of mineral contamination particles was evidenced. The correlation between the presence of 3D aggregates of silica in wood and high content of K and Ca in the ash was established. Employing multivariable theoretical simulation method, the combined effect of mineral contamination, HTC and wood density on the tool dullness appeared to be a reasonable explanation of the results obtained.     

Sperm maturation and capacitation in the open thelycum shrimp Litopenaeus (Crustacea: Decapoda: Penaeoidea)

Transmission electron microscopy was applied to sperm removed from males and females belonging to Litopenaeus vannamei, L. stylirostris and L. occidentalis. It was discovered that a region named filamentous meshwork (FM), located between the nucleus and the hemispherical cap, develops differently in these three closely related species. In L. vannamei, the FM is synthesized in the male reproductive system, but seems to complete its formation after mating. In L. stylirostris, the FM region was not present in spermatophores collected from males or in sperm from the thelycum. In L. occidentalis, the FM region is fully developed in male sperm. It is suggested that completion of the FM is required for acrosome maturation, and the process continues after mating in some species of Litopenaeus. In vitro induction of the acrosome reaction in sperm from males and females of L. occidentalis demonstrated for the first time that reactivity is significantly superior in sperm cells that have been attached to the open thelycum for some hours, as compared to sperm in males (prior to transfer). This finding suggests that matured sperm cells of L. occidentalis become capacitated to react against egg water after mating.     

Effects of ranitidine, famotidine, pantoprazole, and omeprazole on intragastric pH in dogs

OBJECTIVE: To identify the normal gastric acid secretion profile in dogs and determine the degree of gastric acid suppression associated with 4 gastric acid suppressants. ANIMALS: 12 healthy Beagles. PROCEDURE: Intragastric pH was measured continuously for 24-hour periods with a digital recording system placed via a gastrostomy tube. Baseline measurements were obtained when food was withheld and when dogs were fed a standard diet. Dogs were then treated with ranitidine (2 mg/kg, IV, q 12 h), famotidine (0.5 mg/kg, IV, q 12 h), pantoprazole (1 mg/kg, IV, q 24 h), omeprazole (1 mg/kg, PO, q 24 h), or saline solution for 7 days; intragastric pH was recorded on days 0, 2, and 6. Subsequently, the effects of administering famotidine (0.5 mg/kg, IV, q 8 h; 6 dogs) and omeprazole as a suspension (1 mg/kg, PO, q 12 h; 6 dogs) were evaluated. Median 24-hour intragastric pH, percentage of time pH was > or = 3, and percentage of time pH was > or = 4 were determined. RESULTS: Median pH, percentage of time pH was > or = 3, and percentage of time pH was > or = 4 were all significantly higher when food was withheld than when dogs were fed. Famotidine, pantoprazole, and omeprazole significantly suppressed gastric acid secretion, compared with saline solution, as determined on the basis of median 24-hour pH and percentages of time pH was > or = 3 or > or = 4. However, ranitidine did not. Omeprazole suspension suppressed gastric acid secretion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in healthy dogs, famotidine, pantoprazole, and omeprazole significantly suppress gastric acid secretion. Twice daily administration of a suspension of omeprazole, was the only regimen tested that approached the potential therapeutic efficacy for acid-related disease when assessed by criteria used for human patients.     

Comparison of the standard predictive equation for calculation of resting energy expenditure with indirect calorimetry in hospitalized and healthy dogs

OBJECTIVE: To determine the level of clinical agreement between 2 methods for the measurement of resting energy expenditure (REE). DESIGN: Prospective case series. ANIMALS: 77 dogs. PROCEDURE: Oxygen consumption (Vo2) and CO2 production (Vco2) were measured with an open-flow indirect calorimeter in healthy (n = 10) and ill (67) dogs. Measurements were collected at 3 time periods on 2 days. The Vo2 and the Vco2 measurements were then used to calculate the REE values. RESULTS: Mean values of measured (MREE) and predicted (PREE) REEs in healthy dogs and a dog with medical illnesses or trauma were not significantly different. There was a significant difference on day 2 between the MREE and PREE in the group of dogs recovering from major surgery. More importantly, there was significant variation between the PREE and MREE on an individual-dog basis. The PREE only agreed to within +/- 20% of the MREE in 51% to 57% of the dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The level of agreement between these two methods for determining the 24-hour REE was poor in individual dogs. The level of disagreement between the 2 methods indicates that these methods may not be used interchangeably in a clinical setting. Measurement of REE by use of indirect calorimetry may be the only reliable method of determining REE in an individual ill or healthy dog.     

The influence of stoniness and canopy properties on soil water content distribution: simulation of water movement in forest stony soil

Mountainous forest soils usually contain a large number of rock fragments (particle diameter >2?mm), which influence soil properties. Data characterizing hydraulic properties of these soils usually describe only the fine soil fraction (particle diameter <2?mm) properties. To quantitatively describe soil water movement in stony soils, it is necessary to evaluate effective hydrophysical characteristics, involving the influence of stones, that is, the effective hydraulic conductivity and retention capacity should be known. Properties of evaporating surface (plant canopy) also play important role in formation of soil water movement and retention. This work presents results of the study of rock fragments (stoniness) effect on soil water content profiles and soil water dynamics during the season. Stony and homogeneous soil behavior is compared. The effect of different canopies (spruce forest, low vegetation) and bare soil in both types of soils on soil water dynamics is also studied. Stones as a part of soil are decreasing its water capacity and hydraulic conductivity as well. This is expressing in the decrease of stony soil water content retention capacity. High interception capacity of trees, followed by the low undercanopy precipitation, leads to the decreased soil water content of the upper soil layer. Combination of stony soil and dense forest canopy led to the low undercanopy precipitation, to relatively low infiltration totals into soil, and to decreased outflow.