Bioequivalence study in calves of three commercial penicillin/ dihydrostreptomycin fixed combination products for intramuscular injection

A bioequivalence study with three penicillin/dihydrostreptomycin fixed combination products for intramuscular administration was performed in dairy calves. In addition to plasma concentrations of penicillin and dihydrostreptomycin, creatine phosphokinase concentrations were determined during a period of 72 h after administration of the drug products. Considerable differences were observed in the pharmacokinetics of penicillin from the three products. Although the extent of absorption was similar for all products, one product showed a significantly slower release from the site of injection. Except for the AUC , the 90% confidence intervals for these parameters exceeded the acceptable range of 0.80-1.20. Therefore, these products are not bioequivalent with respect to the rate of absorption of penicillin. Concerning the pharmacokinetics of dihydrostreptomycin in calves, it could not be concluded that the products were bioequivalent, since the 90% confidence intervals of the ratios for C _max, t _max and MRT exceeded the range of 0.80-1.20. From this study in calves, it was also found that the product with the slowest release of penicillin from the injection site caused the most severe tissue damage, based on plasma creatine phosphokinase concentrations. Comparing the results from this study in calves with those from a previous study in rabbits, it can be concluded that the rabbit is a good animal model that could substitute for large animals, at least calves, in bioequivalence studies for penicillin/dihydrostreptomycin fixed combination products.     

Comparison of different media for the isolation of small ruminant strains of Mycobacterium paratuberculosis

Two different egg based media, with and without the incorporation of sodium pyruvate, were used to isolate M. paratuberculosis from sheep, goat and cattle samples obtained at our laboratory for two years. Both media were adequate for bovine material, with a slightly improved isolation rate for Herrold's egg yolk medium incorporating sodium pyruvate; however, most of the small ruminant strains grew only on L?wenstein-Jensen medium without sodium pyruvate. Those results point out the need to use different media when working with small ruminant samples and provide further evidence for the existence of different varieties of M. paratuberculosis causing paratuberculosis in cattle and in small ruminants.     

鄱阳湖钉螺体内吸虫尾蚴记述

作者从1999-2000年共解剖鄱阳湖草洲钉螺87146只，先后发现裸头类、矛口类、单盘类、微尾类、叉尾类、对盘类、无尾类尾蚴共15种，本文将各种尾蚴的形态特征予以简介。     

Ketoprofen reduces the minimum alveolar concentration (MAC) in dogs anaesthetized with isoflurane and fentanyl

Non‐steroidal anti‐inflammatory drugs may potentiate the opioid induced reduction in volatile anaesthetic requirements ( Gomez de Segura et al. 1998 ). This study determined the reduction in the MAC of isoflurane (ISO) produced by ketoprofen (KETO) in dogs anaesthetized with fentanyl (FENT) and ISO. Six healthy female crossbred dogs, weighing 13.5 ± 1.3 (mean ± SD) kg and aged 3.0 ± 0.9 years were studied. Approval of the study was obtained from the institutional ethics committee. Anaesthesia was induced in all dogs via a facemask with 5% ISO in 5 L minute^?1 oxygen. The dogs' trachea were intubated and lungs were ventilated to maintain normocapnia (Pe ′CO₂ 4.7–6 kPa, 35–45 mm Hg). A heating pad was used to maintain body temperature. The animals were anaesthetized four times at one week intervals with the following anaesthetic and analgesic protocols randomly administered. Study 1, MAC (ISO); Isoflurane MAC. Study 2, MAC (ISO + FENT); dogs anaesthetized with ISO received a loading dose of 30 µg kg^?1 FENT IV over 20 minutes followed by a maintenance infusion of 0.2 µg kg^?1 minute^?1 FENT. Study 3, MAC (ISO + FENT + KETO1); as study 2 plus 1 mg kg^?1 KETO. Study 4, MAC (ISO + FENT + KETO2); as study 2 plus 2 mg kg^?1 KETO. The MAC was determined in duplicate by applying a standard electrical stimulus (50 V, 50 H₂ over 60 seconds via two needles placed SC over the tarsus). The stimulus was applied 15 minutes after every step change in anesthetic concentration. The Wilcoxon test was applied to data to determine significant differences among MAC measurements. Fentanyl significantly decreased MAC (ISO) from 1.27% ± 0.02% to 0.73% ± 0.08%, a reduction of 42% (p < 0.05). Ketoprofen 1 mg kg^?1 further decreased the MAC value (although not statistically significantly) with a reduction of 47% from MAC (ISO) (0.67% ± 0.13%) and 8% from MAC (ISO + FENT). When KETO 2 mg kg^?1 was given, the reduction in MAC was 50% compared to MAC (ISO) (0.63% ± 0.08%; p < 0.05) and 14% compared to MAC (ISO + FENT) p < 0.05. Administration of KETO further reduces MAC (ISO) compared to levels observed with FENT alone. The observed reduction may have clinical advantages.     

The interrelationships between serum HDL subpopulations and triacyglycerol

AIM: To Study the influence of plasma TG level on the contents of serum HDL subpopulations. METHODS: Classified by the contents of serum TG, the serum level of HDL subpopulations in 106 normal TC and 183 high TC subjects were analyzed by two-dimensional gel electrophoresis coupled with immunodection method. RESULTS: The apo-AⅠcontents of per-β1-HDL, HDL3c, HDL3b and HDL3a were higher in a certain extent in TC high subjects vs corresponding TC desirable subjects. The apo-AⅠ contents of per-β1-HDL （in borer-line high TG subgroup） and HDL3b （in very high TG subgroup） were significantly higher (P<0.05 or P<0.01), while the apo-AⅠ contents of HDL2b and HDL2a were all lower in TC high subjects vs corresponding TC normal subjects. With the increase in plasma TG levels, the apoA-Ⅰ content of pre-β1-HDL increased, and it was significantly higher (P<0.05 or P<0.01) in borderline-high TG(except TC desirable subjects), high TG and very high TG subgroups vs corresponding normal TG subgroup. Contents of HDL3b and HDL3a had the same tendency, and in TC high subjects contents of HDL3b (in very high TG subgroup) and HDL3a (in every subgroups, in which levels of TG were higher) were significantly higher (P＜0.05 and P＜0.01） than in normal TG subgroup. On contrast, the apoA-Ⅰcontents of HDL2b and HDL2a following with the increase of plasma TG levels tended to become lower. Contents of HDL2b were significantly lower (P<0.05) in high TG subgroup and very high TG subgroup vs corresponding normal TG subgroup, and in TC high subjects contents of HDL2a were significantly lower (P<0.05) in very high TG subgroups vs normal TG subgroup. CONCLUSION: Our data show the general shift toward smaller size of HDL particle size with the increase in TC and TG levels. Contents of TC and TG are very important to contents of HDL subclasses.     

Suppression of lymphocyte blastogenesis by porcine interferon-α

Peripheral blood lymphocytes (PBL) from five four-day-old and five six-week-old piglets were treated with 10 to 320 units of porcine interferon-alpha, and their blastogenic responses to phytohaemagglutinin or pokeweed mitogen were compared with those of control lymphocytes. There was significant inhibition of the blastogenic response to phytohaemagglutinin by 320 units of interferon-alpha, and of the response to pokeweed mitogen by 320 and 160 units of interferon-alpha. Porcine interferon-beta was cytotoxic to porcine PBL. The blastogenic response to pokeweed mitogen was significantly higher in PBL from the younger piglets.     

Do summer temperatures trigger spring maturation in Pacific lamprey,Entosphenus tridentatus?

Abstract –  Pacific lamprey, Entosphenus tridentatus , return to streams and use somatic energy to fuel maturation. Body size decreases, the lamprey mature, spawn, and then die. We predicted that warm, summer temperatures (>20 °C) would accentuate shrinkage in body size, and expedite sexual maturation and subsequent death. We compared fish reared in the laboratory at diel fluctuating temperatures of 20–24 °C (mean = 21.8 °C) with fish reared at cooler temperatures (13.6 °C). The results confirmed our predictions. Lamprey from the warm water group showed significantly greater proportional decreases in body weight following the summer temperature treatments than fish from the cool water group. A greater proportion of warm water fish sexually matured (100%) and died (97%) the following spring than cool water fish (53% sexually mature, 61% died). Females tended to mature and die earlier than males, most obviously in the warm water group.     

Wildebeest-derived malignant catarrhal fever: unusual epidemiology in South Africa

The epidemiology of wildebeest-derived malignant catarrhal fever in South Africa differs from the worldwide accepted pattern. Here the occurrence of the disease is often not related to close contact between cattle and wildebeest, and most cases are observed during late winter and spring, when wildebeest calves are 8-10 months old. This is in contrast to the situation in Kenya and Tanzania, where most cases are encountered during autumn, when wildebeest calves are 3-4 months old.     

Algunos aspectos sobre la inervación de pulmon en animales de laboratorio

The finer innervation of the tissues of the lung was studied with several methods of silver impregnation, focussing especially on the fibers and endings of the nerves. The richest terminal innervation could be found in the epithelial and subepithelial tissue, and was sometimes similar to the situation in the smooth muscles which might indicate that, somehow, secretory and motor innervation are alike morphologically. On the other hand, there were many nerve fibers in the perichondrium of the small nodules and plaques of cartilage too, although they did not enter the cartilaginous tissue. The final nerves ended in different forms, from round or ovoid masses to free "ultraterminal" filaments.