Some toxic and enzymatic activities of Bothrops ammodytoides (yarará ñata) venom.

Bothrops ammodytoides, the smallest representative of this genus, is found only in Argentina. Venom was extracted from thirty adult specimens (35-70 cm in length, 90-300 g in weight) captured in the Province of Buenos Aires and kept in captivity. Venom yield was 3-30 mg. SDS-PAGE showed strong bands at 14.0; 23-25; 45; 54 and 63 kDa and weak bands at 17.0; 30.0; 40.0 and 85.0 kDa. Toxic activities were: LD50 (intravenous, mice) 0.5+/-0.2 microg/g; minimal procoagulant dose on human plasma (MPD-P) 35+/-2 mg/l; and minimal defibrinogenating dose (MDD, mice) 6-12 microg. Hemorrhagic and/or necrotic activities appear to play a major role in lethality; minimal hemorrhagic dose (MHD, mice) is 10+/-2 microg/g and minimal necrotizing dose (MND, mice) is 38+/-5 microg. The LD50, MPD-P and MND are among the lowest in venoms from Bothrops species found in Argentina. B. ammodytoides venom exhibited high proteolytic and phospholipase A2 activities. Most of the B. ammodytoides venom components cross-react with Bivalent Bothropic antivenom (Instituto Nacional de Producción de Biológicos ANLIS Dr. G. Malbrin, against B. alternatus and B. neuwiedii venoms). One ml of antivenom neutralizes 1.2 mg of B. ammodytoides venom.

Evaluation of the diagnostic value of plasma copper levels in cattle.

Copper (Cu) is an essential trace element. Depletion of liver-Cu stores leads to clinical or sub-clinical Cu deficiency. Our objective was to evaluate plasma-Cu levels as a diagnostic test for the assessment of Cu status in cattle. We used liver-Cu levels as the gold standard. The chosen cutoff for plasma Cu was 9 mmol/l; two different cutoffs were chosen for liver-Cu: 20 and 10 microg/g dry matter (DM). When 20 microg/g DM of liver Cu was the cutoff, plasma Cu had sensitivity=69% (58, 79) and specificity=84% (74, 93). The same values if the cutoff in liver was 10 microg/g were 92 (82, 100) and 73% (64, 82), respectively. ROC curves showed that the best cutoff to be used for plasma Cu was 8.26 mmol/l; however, no significant improvement was found in sensitivity or specificity. We concluded that interpretation of plasma-Cu levels significantly varies with the liver-Cu cutoff.

Ceroid-lipofuscinosis in a Cocker Spaniel dog.

A neurodegenerative storage disease identified as ceroid-lipofuscinosis by light, fluorescence, and electron microscopic examinations was diagnosed in a 4-year-old female Cocker Spaniel dog with progressive ataxia and proprioceptive deficits. Stored pigment was found within neurons of the brain and spinal cord and in smooth muscle cells of the urinary bladder and small muscular arteries. The microscopic findings resembled those found in six other cases of generalized ceroid-lipofuscinosis in this breed. However, the brown discoloration of the intestines, which was the major gross lesion observed in those cases, was not found. This is the first report of the disease in Argentina.

Comparison between two radiation protective substances in irradiated mice. Effect on splenic haemopoiesis.

The radiation protective action of 2,2'-Dithiobis(N-[(1-adamantyl)-methyl]-acetamidine)-dihyrochloride (S-75) and cysteamine was compared in splenectomized and non-splenectomized mice. Cysteamine was found to have better and more general protection properties. Several indications of a specific effect of S-75 on the spleen were observed. It is suggested that the protection properties of S-75 should be tested in another laboratory animal not having such a marked splenic haemopoiesis as the mouse.

Distribution of 35S in mice after oral administration of alpha-dithioacetamidinium chloride. An autoradiographic investigation.

The distribution of 35S in mice has been investigated by whole-body autoradiography after oral administration of the 35S labelled S-75 (2,2'-Dithiobis(N-[(1-adamantyl)-methyl]-acetamidine)dihydrochloride). The substance was rapidly absorbed, and the highest concentration occurred in the liver and kidneys. During the highest radiation protective activity (after about 45 min) a substantial concentration was found in the red pulp of the spleen. This supports previous findings that S-75 has its most marked protective effect on the splenic haemopoiesis. Previously, it was shown that cysteamine is more evenly distributed in the body than S-75, which is in agreement with its more generalized protective effect than S-75.