Activity pattern of medium and large sized mammals and density estimates of Cuniculus paca (Rodentia: Cuniculidae) in the Brazilian Pampa

Between July 2014 and April 2015, we conducted weekly inventories of the circadian activity patterns of mammals in Passo Novo locality, municipality of Alegrete, southern Brazil. The vegetation is comprised by a grassy-woody steppe (grassland). We used two camera traps alternately located on one of four 1 km transects, each separated by 1 km. We classified the activity pattern of species by the percentage of photographic records taken in each daily period. We identify Cuniculus paca individuals by differences in the patterns of flank spots. We then estimate the density 1) considering the area of riparian forest present in the sampling area, and 2) through capture/recapture analysis. Cuniculus paca, Conepatus chinga and Hydrochoerus hydrochaeris were nocturnal, Cerdocyon thous had a crepuscular/nocturnal pattern, while Mazama gouazoubira was cathemeral. The patterns of circadian activity observed for medium and large mammals in this Pampa region (southern grasslands) may reflect not only evolutionary, biological and ecological affects, but also human impacts not assessed in this study. We identified ten individuals of C. paca through skin spot patterns during the study period, which were recorded in different transects and months. The minimum population density of C. paca was 3.5 individuals per km2 (resident animals only) and the total density estimates varied from 7.1 to 11.8 individuals per km2, when considering all individuals recorded or the result of the capture/recapture analysis, respectively.

Activity patterns of South American silver catfish (Rhamdia quelen)

The South American silver catfish (Rhamdia quelen) is a widely distributed species in Central and South America in areas east of the Andes between Venezuela and the northern parts of Argentina. The bottom dwelling species occurs in lakes and reservoirs as well as in rivers. Between June 2000 and December 2001, sixteen silver catfish were tracked during fourteen 24-h cycles in two-hour-intervals, with the aim of investigating daily movements and habitat use. Covered distances varied between 0 m/2 h and 326 m/2 h and the mean distance covered in 2 h was 25.6 m. The mean activity of individual silver catfish varied between 5.6 m/2 h and 81.4 m/2 h. The swimming activity was linearly related to the total fish length. The highest mean swimming activity occurred in the morning and at nightfall. Silver catfish concentrated in three areas of frequent use. All of them were characterized by steep banks providing shelter in the form of rip-rap or large woody debris. Vertically, silver catfish preferred the upper 2 m layer where tracked fish encountered higher temperatures and higher dissolved oxygen concentrations.

The effects of naturally occurring metabolites (L-cysteine, vitamin C) on cultured human cells exposed to smoke of tobacco or marijuana cigarettes

The effects of vitamin C on the growth of human lung cultures and of vitamin C or L-cysteine on a human breast cancer culture (SK-Br-3) were assessed with and without exposure to fresh smoke from tobacco or marijuana cigarettes. When grown in the presence of vitamin C, lung cultures exposed or not exposed to either type of smoke showed a stimulation of growth and a significant decrease in mitotic abnormalities. However, abnormalities were much more marked in marijuana-exposed cultures than in tobacco-smoke-exposed ones. Nonexposed or tobacco-smoke-exposed breast cancer cultures, when grown in the presence of vitamin C, also showed acceleration of growth of epithelial cells, significant reduction in mitotic abnormalities, and occurrence of pseudoglandular structures, indicating differentiation. These alterations not only disappeared, but the cultures also became fibroblastic when they were returned to media without vitamin C. In contrast, vitamin C did not reduce mitotic abnormalities in marijuana-smoke-exposed breast cancer cultures, but stimulated abnormal growth and dedifferentiation. In nonexposed, tobacco-, or marijuana-smoke-exposed breast cancer cultures. L-cysteine evoked an acceleration of fibroblastic growth, which was not altered when the cultures were returned to media without L-cysteine.

Protection of hamster lung cultures by L-cysteine or vitamin C against carcinogenic effects of fresh smoke from tobacco or marihuana cigarettes

Sequential morphological and cytochemical effects of L-cysteine and vitamin C were assessed on hamster lung cultures exposed to smoke from either tobacco or marihuana cigarettes.

Hamster lung cultures, when grown in normal media (Eagle-Dulbecco) without L-cysteine (NM), and exposed to fresh smoke from either tobacco or marihuana cigarettes for 1-8 weeks, displayed cytotoxic alterations, loss of lysosomes, and marked abnormalities of cell division and of DNA content of chromosomes, while cultures exposed in the same manner and grown in the same NM, but to which L-cysteine was added, showed increase of lysosomes and significantly less abnormalities in cell division and DNA content of chromosomes (P<0·005). Cultures grown in NM and exposed for 9-24 weeks to smoke (whole smoke or gas vapour phase) disclosed more and more rapid irregular growth of fibroblasts and/or malignant transformation, while cultures grown in NM with L-cysteine and exposed in the same manner to smoke resembled closely those of non-exposed controls. Non-exposed control cultures grown in NM did not show significant differences from those grown in NM+L-cysteine, except that controls with L-cysteine also showed increase of lysosomes, accompanied by a reduced growth rate.

Addition of vitamin C to NM had a similar effect on growth of control and smoke exposed cultures as L-cysteine, but the cultures were less regular and grew more rapidly than with L-cystene. There was also occurrence of multinucleated giant cells.

Cultures grown in NM which had undergone malignant transformation continued their abnormal growth during the examined period (over 2 years). However, when such transformed cultures were grown for 3 months or longer in NM with L-cysteine or vitamin C, the growth became more and more normal, and the cultures resembled closely those of non-exposed controls.

These results suggest that, in hamster lung cultures, addition of L-cysteine or vitamin C to media protects against or reverses abnormal growth and malignant transformation occurring either in aged controls (1-2 years old) or in young cultures (3-6 months old) after repeated exposure to smoke from tobacco or marihuana cigarettes. The increase of lysosomes after L-cysteine or vitamin C also points to the possible importance of lysosomes in protecting the cultures against the enhancement of carcinogenesis by smoke.

SH Reactivity of cigarette smoke and its correlation with carcinogenic effects on hamster lung cultures

After hamster lung cultures were exposed repeatedly to puffs of fresh smoke from 7 types of cigarettes containing variable amounts of particulate and gas vapour phase components, atypical growth and/or malignant cell transformation were observed within a period of 3-6 months. A positive correlation was demonstrable between high SH reactivity and high NO content of the gas vapour phase and malignant transformation. There was no positive correlation for the other analyzed components of the smoke, including tar content.

Ultrastructural studies on cells of hamster lung cultures after chronic exposure to whole smoke or the gas vapour phase of cigarettes

High levels of gas vapour phase constituents in cigarette smoke enhanced abnormal growth and tumorigenicity in primary cultures of hamster lung cells regularly exposed over long periods to the smoke from one of three types of cigarette. The ultrastructure of such cells was investigated by electron microscopy. Cells from cultures exposed to low levels of gas vapour phase constituents resembled cells from control, non-exposed cultures, and were filled with secondary lysosomes of the autophagic vacuole type. These autophagic vacuoles contained dense particles similar in size to the nucleoids of certain viruses. Cells from cultures exposed to high levels of gas vapour phase constituents and cells from tumours formed in nude mice after subcutaneous injection of transformed cultures lacked autophagic vacuoles but contained a higher number of cytoplasmic microfilaments. R-type (equals H-type) virus particles were found in the ER cisternae of control and exposure cultures at all ages, whilst A-type virus particles were found in close association with mitochondria in a transformed, exposed culture and in control cells which also formed tumours in nude mice but only after a much longer culture period.

THE INFLUENCE OF "FOLIC ACID" ON SPONTANEOUS BREAST CANCERS IN MICE

Complete regressions of spontaneous breast cancers in mice were observed in 38 among 89 animals (43 per cent.). The treatment consisted of daily intravenous injections of 5 micrograms of l. casei factor ("folic acid"). The treated animals lived longer than the controls, especially the healed mice. The incidence of the development of new tumors was decreased among the treated mice as compared with the controls.

The treatment of spontaneous breast adenocarci-nomas in mice with extracts of spleen or yeast

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