Comparison of two insulin protocols for diabetic dogs undergoing cataract surgery

Objective To evaluate the effectiveness of two insulin doses to maintain an acceptable range of blood glucose concentrations (70–200 mg dL^?1) in the peri‐operative period in diabetic dogs. Animals Twenty‐four diabetic dogs with a median weight of 20.6 kg and a median age of 8 years old. Methods The dogs were randomly assigned to receive either 25 or 100% of their normal insulin dose subcutaneously on the morning of surgery. The anesthetic and feeding protocols were standardized. On the day before surgery, venous blood was collected for measurement of β‐hydroxybutyrate, cholesterol, glucose, glycosylated hemoglobin, hematocrit, total plasma protein and urea nitrogen. On the day of surgery, blood glucose concentrations were measured prior to anesthesia, prior to the start of surgery, 1 and 2 hours after beginning of surgery, 1 hour after extubation, at 16 : 00 hours and at 20 : 00 hours. β‐hydroxybutyrate concentrations were measured at 20 : 00 hours that day. At 08 : 00 hours the following day, β‐hydroxybutyrate and glucose concentrations were measured. The significance of differences between groups was tested with Wilcoxon's two‐tailed rank‐sum test, Chi‐square test and Fisher's exact test. Results There were no differences in insulin treatments, clinical signs, concurrent diseases and most clinicopathological parameters between the two groups of dogs at entry to the study. The 25% dose group had blood glucose values of 296 (102–601) mg dL^?1 at 16 : 00 hours and 429 (97–595) mg dL^?1 at 20 : 00 hours on the day of surgery. The 100% insulin dose group had lower corresponding values of 130 (55–375) mg dL^?1 (p = 0.04) and 185 (51–440) mg dL^?1 (p = 0.004). No other differences (p < 0.05) were detected between the two groups. Conclusions The administration of a full dose of insulin is only marginally advantageous for reducing glucose to normal (70–120 mg dL^?1) after anesthesia but neither dose consistently induced glycemic values in an acceptable range (70–200 mg dL^?1) or normoketonemia. Clinical relevance Blood glucose should be measured immediately before anesthesia and periodically throughout the peri‐operative period in all diabetic dogs because presurgical subcutaneous administration of 25 or 100% of the normal insulin dose resulted in unpredictable blood glucose concentrations.     

Assessment of the Hemocue-b for measuring hemoglobin in horse blood

Our purpose was to assess the accuracy and precision of a point of care hemoglobinometer (HemoCue‐B hemoglobin photometer) for measuring hemoglobin concentration in horse blood. Samples of jugular venous blood from 12 healthy adult horses were collected in EDTA. In order to test the device over a wide range of values, each sample was divided into nine aliquots, and autologous plasma was added or removed from the aliquots to produce blood with PCV values that approximated 5, 10, 20, 30, 40, 50, 60, 70, and 80%, respectively. The aliquots were rocked to ensure mixing of plasma and cells. Then hemoglobin by HemoCue‐B (Hb_HQ) and hemoglobin by the cyanmethemoglobin method (Hb_CY) were measured on each aliquot. The PCV of each aliquot was also measured and this value was used for subsequent analyses. To test repeatability, hemoglobin was measured twice by the HemoCue‐B on approximately 40% samples. Samples with Hb_HQ >25.4 g dL^?1 required dilution prior to analysis. Hb_CY ranged from 1.6 to 33.4 g dL^?1. After regression, Hb_CY = ?0.16 + 1.04 Hb_HQ (n = 101; r² = 99.6%). By inspection of a modified Bland‐Altman plot, Hb_HQ values <16 g dL^?1 closely approximated Hb_CY; however, at greater values, Hb_HQ underestimated Hb_CY by as much as 3.2 g dL^?1. The difference between repeated measurements with the HemoCue‐B was 0.02 ± 0.16 g dL^?1 (mean ± SD; n = 10) and nonsignificant. After regression, PCV = ?0.76 + 2.78 Hb_HQ (n = 101; r² = 99.4%). We conclude that HemoCue‐B can be used to measure hemoglobin concentration in horse blood, and that it is accurate when hemoglobin is <16 g dL^?1. PCV can be estimated by multiplying Hb_HQ by 2.8 and then subtracting 0.8.     

Validating CERES-wheat under North-German environmental conditions

The predictive quality of CERES-wheat was tested under contrasting nitrogen management and temperate-maritime climate conditions of North-Germany. Field data from 9 years of observations were used in this study. The magnitudes of the genetic parameters of the local wheat cultivar “Orestis” were strongly influenced by seasonal weather fluctuations. For predicted yield and harvest biomass, the root mean square error was 2.2 t/ha and 3.2 t/ha, respectively. These errors were too large to permit a practical application of the CERES-wheat model for optimizing fertilizer management under the production conditions of North-Germany. The results of this study suggest that the model needs to be considerably improved with respect to the simulation of soil and plant water-relations, as well as the interaction between water and nitrogen uptake which were found to be inconsistent.     

Sensitivity of boreal forest carbon balance to soil thaw

We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 +/- 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 +/- 0.2 ton C ha-1 year-1 in moss and wood offset by a loss of 0.8 +/- 0.5 ton C ha-1 year-1 from the soil. The soil remained frozen most of the year, and the decomposition of organic matter in the soil increased 10-fold upon thawing. The stability of the soil carbon pool ( approximately 150 tons C ha-1) appears sensitive to the depth and duration of thaw, and climatic changes that promote thaw are likely to cause a net efflux of carbon dioxide from the site.     

Testing Milkofix, a new preservative preparation for milk samples used for infrared analysis of milk components. II. Verification of its preservative effects in relation to infrared analysis]

For the purposes of the infrared analysis of the basic milk composition, Milkofix, an ecologically friendly preparation used for milk sample preservation (Trzicky, 1990), was compared with untreated samples (N) and with samples preserved with sodium azide (A), bronopol (B) and potassium dichromate (C) at a storage temperature of 20 degrees C (I) and 4 degrees C (II) in samples kept for 14 and 18 days. Pursuant to the recommendations cited in literature, the preservatives had these concentrations: A = 0.0085 g NaN3 and 0.0630 g NaCl; B = 0.0050 g bronopol and 0.0500 g NaCl; C = 0.0330 g K2Cr2O7 and 0.0670 g KCl; M = 0.1250 g, all amounts are per 25 ml milk. Three bulk milk samples were used which were analyzed on an automatic Milko-Scan 133 B infraanalyzer (Foss Electric, Denmark) every day. On the basis of a graphical evaluation of the results by IDF recommendations (1985) the times within which the applicable results could be obtained were determined for the various methods of milk sample treatment (Figs. 1 to 6): N I--0 days; A I--9; B I--10; C I--13; M I--4; N II--10; A II--5; B II--11; C II--15; M II--10 (Tab. I). The results recorded for Milkofix are in agreement with the conclusions drawn in the previous study, where the intervals of four and nine days were determined. The days to milk sample coagulation were as follows: N I--1 day, M I--10 days. The coagulation in A I, B I, C I and N II samples was not observed even after 13-day storage and in A II, B II, C II and M II samples not even after 17 days of storage. The results for particular components (fat, proteins, lactose) of milk samples differently treated in time are presented in Tabs. II, III and IV. A system of evaluating criteria (Tab. V) was used to determine the order beginning from the most convenient method of milk sample treatment for the given purpose: 1. C II, 2. C I, 3. B II and A I, 4. B I, 5. M II, 6. N II, 7. A II, 8. M I and 9. N I.(ABSTRACT TRUNCATED AT 400 WORDS)     

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep

Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.     

Maturation Status, Protein Synthesis and Developmental Competence of Oocytes Derived from Lambs and Ewes

The efficacy of oocyte selection for in vitro embryo production depends on the abundance and diameter of follicles, cumulus layers around the oocytes and subsequent fertilization. Application of `ovum pick-up' technique allows us to utilize partially matured oocytes for embryo production even from juvenile subjects. To compare their developmental competence, oocytes derived from lambs and ewes and cultured in maturation medium for up to 26 h were assessed at 2 h intervals by confocal microscopy after chromatin and microtubulin-specific fluorochrome labelling. Lamb oocytes reached second meiotic metaphase (MII) at lower numbers at 24 h (60.0%) and 26 h (28.6%) whereas 85.7% of adult-derived oocytes attained MII status by 24 h of maturation. Radiolabelling of oocyte proteins revealed higher incorporation of [³⁵S-]-methionine and [³⁵S]-cysteine in adult-derived oocytes compared to lamb oocytes. Although the cleavage rate of lamb oocytes was similar to that of ewe oocytes, the proportion reaching blastocyst stage was significantly lower (p < 0.05) in the lamb-derived oocytes. However, blastocysts from both types of oocytes displayed similar cell lineage allocations to inner cell mass and trophectoderm.     

Tests of Milkofix, a new preservative preparation for milk samples used for infrared analysis of milk components. I. Verification of its bacteriostatic and bacteriocidal effects and its interference effects]

Hygienic, ecological and health problems of sample preservation for an analysis of basic milk components make us continually to develop a safer chemical preservative substance which will preserve the original sample composition for the time required and which will not influence the analyses. Trzicky (1990) proposed Milkofix (M), a preservative substance on the basis of silver compound. The author reports on minimum risks of the use of this preparation, in comparison with traditional preservatives. Preservative efficiency of Milkofix was compared with other preservatives: K2Cr2O7 (C), NaN3 (A) and bronopol (B). The following concentrations were used: A--0.0085 g NaN3 and 0.0630 g NaCl, B--0.0050 g bronopol and 0.0500 g NaCl, C--0.0330 g K2Cr2O7 and 0.0670 g KCl in tablet, M--0.1250 g of the mixture, all amounts are per 25 ml milk. The observed antibacterial efficiency of M could be seen in a slower decrease in actual acidity, and/or in an increase in titratable acidity in M-treated samples unlike untreated ones (N). From the starting value pH 6.3 (Fig. 1), the value of N treatment dropped to 3.8 after two days, the values of M and A treatments dropped to 4.9 after nine days and to 5.7 after twelve days, respectively. As for SH, the values increased within the same interval from 6.5 (2.5 mmol/l) to 28.6 in N, and to 22.3 in M and 9.4 in A (Fig. 3). There was a similar trend when the milk samples were stored at a temperature of 4 degrees C, but the differences between the preservation methods were not so clear in comparison with storage at a temperature of 20 degrees C (Figs. 1 and 3). The standardized SH value of 9.0 (2.5 mmol) for infraanalyzer measurements was exceeded after 24 hours in N samples, after four days in M samples and after 12 days in A samples at a temperature of 20 degrees C. The observation of the growth of microorganism counts (CPM) showed that this growth was slower in M than in N, but faster in the samples of C treatment (Fig. 5). The generative time of CPM in N made 1.6 hours, in M 2.4 hours and in C 7.9 hours. The lag phase of these mixed cultures was 24 hours in M, 60 hours in C and in N treatment the lag phase was zero.(ABSTRACT TRUNCATED AT 400 WORDS)