Absorption rate and plasma and fat disposition of lindane after various lindane percutaneous treatments in shorn and unshorn sheep were investigated. To analyze data with a deconvolution method, IV administration was performed to determine the basic pharmacokinetic values of lindane in sheep. After IV administration, the steady state volume of distribution was very high (8.07 +/- 3.60 L/kg of body weight), and the mean residence time was long (28.1 +/- 11.7 hours). Deconvolution analysis indicated that lindane absorption was continuous until 33 to 41 days after spraying with a 0.025% lindane solution. Total amount of absorbed lindane in shorn (15,171 +/- 4,463 microgram/kg) sheep was about twice that in unshorn (7,615 +/- 3,128 microgram/kg) sheep; from deconvolution analysis, it was calculated that the time required for 50% of the available dose to be absorbed was between 115 and 179 hours. After percutaneous lindane administration, the fat concentration was compared with the available lindane dose. The apparent half-life of lindane elimination in fat was 225 +/- 47.4 hours, which is similar to the value calculated for the absorption rate constant. By comparing fat and plasma concentrations, it was calculated that for a mean plasma concentration of 5 ng/ml, the fat lindane concentration was 1.65 +/- 0.87 microgram/g (ie, lower than the generally accepted tolerance level of 2 microgram/g).

The macrolytic lactone F28249-alpha was titrated in experimentally infected sheep and found to be highly effective against most of the common gastrointestinal nematodes as a single oral dose, given at a rate of 0.025, 0.05, or 0.1 mg/kg. Specifically, maximal activity was evident at even the lowest dosage against adult Haemonchus contortus, Ostertagia circumcinta, Trichostrongylus axei, and T colubriformis and L4 O circumcinta. Activity against Oesophagostomum columbianum was also high at all dosages, with a calculated ED95 of 0.029 mg/kg. Cooperia curticei was eliminated at 0.1 mg/kg, but control was erratic at the lower dosages. The greatest weakness of this compound was its activity against C oncophora. The activity against this parasite was weak (<less than or equal to 85%) at all dosages, and the dosage-response curve was flat, suggesting dosages substantially higher than those given would be necessary for high-order control of this species.

<p>The hepatic veins and their sectors of drainage have been studied in 40 livers of ovines. In 35 organs the venous system was injected with "Neoprene Latex 650" and then dissected; in the other 5 it was injected with vinyl acetate (different colors) in order to obtain plastic models. The authors observed that hepatic lobes and their sectors were drained by the following hepatic veins and their tributaries. Major hepatic veins (left hepatic vein, middle hepatic vein, right hepatic vein(s), hepatic vein of the caudate process and hepatic vein of the papillary process), and minor hepatic veins. The left and the middle hepatic veins were the main vessels to drain the blood from the liver of <em>Ovis aries </em>and ended independently into the caudal vena cava. The right hepatic vein(s) terminated in the caudal vena cava only in 57.1% of the cases as it joined the vein of the caudate process or of the papillary process in 31.4% one or more right hepatic vein(s) occurred in 88.6% of the cases, a single vein being more frequent (51.4%) than two (22.9%) or three (14.3%) veins. In a few cases the vein of the caudate process formed a trunk with the right hepatic vein and/or the vein of the papillary process (11.4%). Alone or in conjunction with others the vein of the caudate process terminated into the caudal vena cava. The vein of the papillary process ended independently into the caudal vena cava, in 71.4% of the cases. Alone or in conjunction with the vein of the caudate process and/or the right hepatic vein, it ended into the caudal vena cava. Minor hepatic vein, opening directly into the caudal vena cava, completed the drainage of the dorsal and medial sectors of the right lobe and the supraportal portion of the caudate lobe. In the vast majority of cases there were no large anastomoses between veins of adjacent anatomicsurgical segments, limited by avascular or paucivascular areas. The venous drainage network was independent and intertwined with the portobilioarterial network. The venous drainage network included in the majority of cases the following anatomicsurgical segments: a) segment of the left hepatic vein (left lobe); b) segment of the middle hepatic vein (quadrate lobe, the supraportal portion of the caudate lobe, the lateral and intermediate sectors of the right lobe; c) segment of the right hepatic vein(s), typically represented by the dorsal sector of the right lobe; d) segment of the vein of the caudate process; e) segment of the vein of the papillary process. The medial sector of the right lobe is drained by the minor hepatic veins.</p> | <p>As veias hepáticas e seus setores de drenagem foram estudados em 40 fígados de ovinos. Em 35 órgãos o sistema venoso foi injetado com Neoprene Latex "650" e em seguida dissecado; nos outros 5 órgãos injetou-se acetato de vinyl (cores diferentes) para obtenção de moldes. Foram observados os lobos hepáticos e seus setores de drenagem das seguintes veias hepáticas e suas tributárias: veias hepáticas maiores (veia hepática esquerda, veia hepática média, veia hepática direita, veia hepática do processo caudado e veia hepática do processo papilar) e veias hepáticas menores. As veias hepáticas esquerda e médias.são os principais vasos de drenagem do sangue do fígado de Ovis <em>aries, </em>desembocando independentemente na veia cava caudal. A veia hepática direita termina na veia cava caudal como vaso único em 57,1% dos casos e junta-se à veia hepática do processo caudado ou veia hepática do processo papilar em 31,4% dos casos. A veia hepática direita ocorre em 88,6% dos casos, sendo em número de uma em maior frequência (51,4%), de duas (22,9%) ou de três (14,3%) veias. Em alguns casos a vaia hepática do processo caudado forma um tronco com a veia hepática direita e/ou a veia hepática do processo papilar (11,4%). Sozinha ou em conjunto com outras, a veia do processo caudado termina na veia cava caudal. A veia hepática do processo papilar chega independentemente na veia cava caudal em 71,4% dos casos. Sozinha ou em conjunto com a veia hepática do processo caudado e/ou a veia hepática direita, desemboca na veia cava caudal. Veias hepáticas menores chegam diretamente à veia cava caudal, completando a drenagem dos setores dorsal e medial do lobo direito e da porção supraportal do lobo caudado. Em grande maioria dos casos existem anastomoses entre veias de segmentos anatomo-cirúrgicos adjacentes, limitados por regiões avasculares ou paucivasculares. A drenagem venosa hepática é formada por vasos independentes mas, interpostos com os vasos integrantes da rede portobiloarterial. A drenagem venosa inclui na maioria dos casos os seguintes anatomo-cirúrgicos: a) segmento da veia hepática esquerda (lobo esquerdo); b) segmento da veia hepática média (lobo quadrado, porção supraportal do lobo caudado e setores intermédio e lateral do lobo direito); c) segmento da veia hepática direita, tipicamente representado pelo setor dorsal do lobo direito; d) segmento da veia hepática do processo caudado; e) segmento da veia hepática do processo papilar. O setor medial do lobo direito é drenado pelas veias hepáticas menores.</p>