Changes in Placental Hormone Secretion After Dexamethasone Treatment in Cattle

Contents Catheters were surgically placed in the uterine artery and vein of four control and four dexamethasone (DXMS)-treated cows on days 248 or 249 of gestation; at the same time the corpus luteum was removed and all animals were treated with 10 mg chlormadinone acetate i.m. daily to maintain pregnancy. After one day of blood sampling which began on day 250, animals received either 20 mg DXMS crystalline suspension i.m. or only the vehicle solution. Blood sampling was then continued for five additional days. Plasma was assayed for unconjugated estrone (E1), progesterone (P4), and pregnenolone (P5). Concentrations of El were higher in the venous samples (p < 0.02) and increased over time (p < 0.02). There was a site x time interaction (p < 0.05) and a significant effect of DXMS-treatment on the linear component (p < 0.02) of the slope values for the El concentrations for both sampling sites. Concurrently, there was an effect of time on P4 concentrations (p lt; 0.01), the venous P4 concentrations were higher (p < 0.01), and there was also a site x time interaction (p < 0.01) but not treatment effect. There was no significant effect on concentrations of P5 between treatment goups or sampling sites. It is concluded that DXMS activates the synthetic system(s) involved in production of estrone in the cow during late pregnancy. This change in estrone synthesis occurred at an increasing rate during the 5 day sampling period. The data are consistent with the hypothesis that the placenta must be capable of utilizing precursors in the cholesterol or pregnenolone group for estrone synthesis and that the major pathway could be the delta-5 pathway. Inhalt: Veränderungen in der placentären Hormonsekretion beim Rind nach Behandlung mit Dexamethason. Bei insgesamt 8 Kühen wurden am 248./249. Tag der Trächtigkeit Katheter in die Vena und Arteria uterina eingelegt, gleichzeitig wurde das Corpus luteum entfernt und zur Aufrechterhaltung der Gravidität wurden 10 mg Chlormadinonacetat täglich während der gesamten Versuchsdauer i.m. verabreicht. Nach einer ersten Blutentnahmeperiode am Tag 250 erhielten jeweils 4 Tiere entweder 20 mg Dexamethason (kristalline Suspension) bzw. das Vehikel (Kontrollguppe) i.m. verabreicht. Die Blutentnahmen erfolgten über weitere 5 Tage, erfaßt wurde der Verlauf von freiem Estron, Progesteron und Pregnenolon. Die in der Vena uterina gemessenen Estronkonzentrationen lagen jeweils höher (p < 0,02) als in der entsprechenden Arterie und stiegen bis zum Ende des Experiments an (p < 0,02). Weiterhin zeigte sich eine Interaktion zwischen dem Ort der Blutentnahme und dem Zeitpunkt (p < 0,05), der Anstieg der Estronkonzen-trationen nach der Behandlung mit Dexamethason war – bezogen auf die lineare Komponente – sigifikant erhöht (p < 0,02). Für P4 ergab sich ein deutlicher Abfall (p < 0,01), wobei in der Vena uterina stets höhere Werte gemessen wurden als in der Arteria uterina (p < 0,01). Auch hier war eine Interaktion zwischen dem Zeitpunkt und dem Ort der Blutentnahme gegeben (p < 0,01), allerdings konnte ein Behandlungs-effekt nicht dargestellt werden. Für Pregnenolon ergaben sich keine Unterschiede zwischen Arteria und Vena uterina sowie den Behandlungsgruppen. Die Ergebnisse zeigen, daß eine einmalige Behandlung mit Dexamethason zu einer zunehmenden Steigerung der Estronproduktion führt, im Hinblick auf die unveränderte Progesteronsekretion wird geschlossen, daß dabei eher der Delta-5-Syntheseweg zugrundeliegen könnte und daß die entsprechenden Precursoren auf der Ebene des Cholesterins oder Prepenolons zu suchen sind.     

Alterations in selected serum biochemical constituents in equids after induced hepatic disease

Effects of induced cholestasis and hepatocellular necrosis and of fasting on serum biochemical constituents including bile acids, IgA, bilirubin, alkaline phosphatase, gamma-glutamyltransferase (GGT), arginase, and the clearance of sodium sulfobromophthalein were studied in 4 groups of equids. The reference value for serum bile acids, as determined by an enzymatic colorimetric procedure for horses and ponies was 5.94 +/- 2.72 mumol/L, there being no statistical difference for horses and ponies. Sample collection at time of feeding had no effect on serum bile acid concentration. Seemingly, serum bile acids, arginase, and GGT were the most sensitive indicators of cholestasis and/or hepatocellular necrosis and would form an essential minimum effective battery of tests to diagnose and prognose hepatic disease in equids. These tests provided a measure of hepatobiliary transport function (bile acids), cell necrosis (arginase), and cholestasis (GGT and bile acids).     

Use of alkaline phosphatase staining to differentiate canine osteosarcoma from other vimentin-positive tumors

Aspiration of lytic bone lesions is an excellent diagnostic test in the initial evaluation of primary bone neoplasia. However, cytologically, it can be difficult to differentiate osteosarcoma (OSA) from other bone neoplasms, including fibrosarcoma, chondrosarcoma, synovial cell sarcoma, and plasma cell myeloma. The purpose of this study is to determine the sensitivity and specificity of alkaline phosphatase (ALP) staining to differentiate OSA from other tumors that express vimentin by immunocytochemistry or immunohistochemistry. ALP is a hydrolytic enzyme present in multiple tissues including liver, kidney, intestine, placenta, and bone. Hypothetically, neoplasms actively producing bone should be specifically positive for ALP staining. Unstained, cytologic specimens were incubated for 8-10 minutes with nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate toluidine salt-phosphatase substrate. A positive reaction stains the membrane of the cells gray to black. Samples were counterstained with a Romanowsky's stain to determine whether the sample was of representative cellularity. A total of 61 vimentin-positive neoplasms have been evaluated and confirmed histopathologically. Tumors that expressed vimentin and were positive for ALP included 33 OSAs, one multi-lobular tumor of bone, one amelanotic melanoma, and one chondrosarcoma. Tumors that expressed vimentin and were negative for ALP included chondrosarcomas (three of four), multiple fibrosarcomas, and multiple synovial cell sarcomas. The sensitivity is 100%, and the specificity is 89%. In conclusion, ALP appears to be a highly sensitive and fairly specific marker in the diagnosis of OSA.     

How to obtain a blood pressure measurement

Noninvasive blood pressure measurement is now a standard diagnostic test in small animal practice. Factors such as patient selection, environment, technical support staff, and necessary equipment and supplies will be discussed. Step by step techniques for obtaining reliable blood pressure measurements in both cats and dogs are presented.     

Embryonaler Fruchttod bei einer Kuh im Anschluß an eine Nachbesamung — nachgewiesen mit Hilfe der Progesteronbestimmung im Blut

Inhalt: Mit Hilfe der kompetitiven Proteinbindungsreaktion wurde Progesteron im peripheren Blut einer Kuh vom 16. his 56. Tag nach der Erstbesamung bestimmt. Die hohen Progesteronwerte, zum Teil über 10 ng/ml Plasma, his zum Tag der 2. künstlichen Insemination (Tag 27) lassen den Schluβ zu, daβ bereits die Erstbesamung zu einer Konzeption geführt hatte und zum Zeitpunkt der Zweitbesamung ein lebender Embryo vorlag. Die 2. Insemination, die aufgrund äuβerer Brunstsymptome durchgeführt wurde, hatte ein Absinken des Progesteronhlutspiegels auf Werte unter 1 ng/ml Plasma zur Folge. Daran schloβ sich ein normaler Zyklus von 20tägiger Dauer an. Dieser hormonanalytisch belegte Fall eines durch Nachbesamung ausgelösten embryonalen Fruchttodes unterstreicht die Forderung der Kliniker, vor Nachbesamungen die Eierstöcke auf das Vorhandensein eines Corpus luteum graviditatis zu kontroilieren.     

Consequences of nutritional and husbandry factors on the heat production of rats and broilers. 2. Effect of environmental temperature on the heat production of fully grown broilers and rats

In an experiment with broilers (origin Tetra B) and with rats (albino, Wistar line) with 2 animals each, heat production was ascertained by measuring CO2 production and O2 consumption over 20 minutes after their feeding 18 h and 1 h before the beginning of measuring at ambient temperatures of 30, 25, 20, 15 and 10 degrees C. Every variant was followed through over 6 h/d in 12 measuring sections. The feed amount/ánimal and day was adapted to energy maintenance requirement. At the beginning of the experiments the broilers and rats were 14 and 21 weeks old resp. and weighed 2.2 kg and 220 g resp. The variation of the ambient temperature did not influence the heat production of the broilers. In contrast to this, the time of feeding in relation to the beginning of measuring had a distinct effect on heat production. Whereas a heat production of 342 +/- 34 kJ/kg LW0.75.d was ascertained in the postabsorptive state 18 h after the last feed intake, it increased by 11% to 393 +/- 32 kJ/kg LW0.75.d when measuring began 1 h after feeding. The very act of feed intake increased heat production by 75%. Rats showed a distinct increase of heat production caused by a decreasing ambient temperature. In the temperature range of 30-25 degrees C the increase was shallower than in the range of 25-10 degrees C. Per 1 degrees C below 25 degrees C heat production increased by 30 kJ/kg LW0.75.d. The increase was independent of the metabolism level, which was influenced by the feeding variants. The results are discussed in connection with Rubner's theory of heat compensation.