Induction of leukaemia in chloramphenicol-treated toads

Chloramphenicol has been associated with the development of aplastic anaemia. As it is still widely used in Egypt, we studied its effect on 100 Egyptian toads [Bufo regularis] given a dose of chloramphenicol of 5 mg/40 g body weight for 12 weeks. We found it induced numerous, severe ultrastructural changes in almost all types of leukocytes. These changes were similar to those induced by the chemical carcinogen 7,12-dimethylbenz[a]anthracene in 100 toads used as the carcinogen control group, and similar to those in leukocytes reported in humans with leukaemia. We recommend regulations be applied on the use of this antibiotic in countries where it is still widely used

Long-term administration of vitamin A and the process of spermatogenesis

The effect of retinoids on spermatogenesis in adult male gerbils [Gerbillus cheesemani] was studied using light and electron microscopy. Treatment with either 13-cis-retinoic acid or retinol acetate was given for 6 weeks and their effects were compared with controls. It was found that 13-cis-retinoic acid induced almost complete cessation of spermatogenesis and produced alterations in the cytoplasm of Leydig cells. No differences were seen in the testis of animals treated with retinol acetate compared with controls using light microscopy but it appeared to produce noticeable ultrastructural changes in Leydig cells. The changes observed were reversed 12 weeks after stopping treatment. Caution should be exercised regarding the use of dietary retinoids in the prevention of cancer

Survey of hormonal levels in meat and poultry sold in Alexandria, Egypt

An analysis of residues from anabolic agents found in commercially available meat and poultry was undertaken in Alexandria, Egypt. This study shows that beef meat samples purchased from government cooperative supermarkets exhibit higher levels of the synthetic growth promoter, trenbolone acetate, than meat from private butchers; however, estrogen levels were much higher in chicken obtained from private growers. A comparison of different cooking methods was conducted on the chicken samples; boiling without skin is recommended to reduce the consumer's intake of hormonal residues

Implications of fructose in liver tumours of the Egyptian toad

Environmental factors play an important role in the etiology of several types of cancer; this discovery has led to a great deal of interest in the role of diet in cancer etiology. It is well known that some factories which produce jams and juices use fructose rather than glucose or sucrose to sweeten their products. This study demonstrates that fructose insignificantly enhances the incidence of liver tumours in Egyptian toads previously injected with 7,12-dimethylbenz [a]-anthracene

Effect of 13-cis-retinoic acid on plasma levels of FSH, LH and testosterone in male New Zealand rabbits

Daily treatment of adult male New Zealand rabbits with 13-cis- retinoic acid [1 mg/kg body weight] for 6 weeks lead to a gradual increase in the plasma level of FSH. LH concentrations were also increased, the degree of increase flucuated during the 6 week treatment period. Plasma testosterone values increased up to the end of the third week of treatment then declined to a level lower than control values. Atrophy of the testis and an inhibition of spermatogenesis was observed in the rabbits treated for 6 weeks with 13-cis- retinoic acid. These results provide evidence that chronic 13-cis- retinoic acid treatment results in changes in endocrine activity of male New Zealand rabbits

Nyctotheroides puytoraci as a single cell model for detecting the antitumor activity of ASTA-Z-7557 and cyclophosphamide

Injections of toads, Bufo regularis, with 0.5 mg/50 g body weight of 3-methylcholanthrene [MC] induced cyst formation in its parasitic protozoa, Nyctotheroides puytoraci, in 28 cases out of 36 cases. Injections of toads with the same dose level of MC + 1 mg of ASTA-Z- 7557 induced encystment in 6 cases out of 39 cases. However, injections of the experimental animals with the same dose level of MC + cyclophosphamide [CY] induced encystment in 10 cases out of 43 cases. On the other hand, injections of the host with 1 mg of ASTA- Z-7557 or CY alone failed to induce cyst formation in the parasite

Effect of vitamin A [retinoic acid] on the fine structure of ascites sublimes of the 13762 rat mammary adenocarcinoma

Cytological differences have been observed in ascites sublines of the 13762 rat mammary adenocarcinoma after treatment with retinoic acid. Before treatment, both MAT-B[1] and MAT-C[1] cells have large irregularlyshaped nuclei, with one or two nucleoli. The cytoplasm contains well developed Golgi complex [Gs and GV] and much endoplasmic reticulum [RER]. Some MAT-B[1] and MAT-C[1] cells contain a small number of [orthodox] configuration mitochondria while others reveal a large number of [condensed] configuration mitochondria. MAT-B[1] and MAT-C[1] after being subjected to vitamin A acid showed that the secretory apparatus [i.e. Golgi complex] has regressed and the endoplasmic reticulum also diminished. In cells containing either [orthodox] or [condensed] configuration, mitochondria revealed vacuolization. In addition, there is an obvious decrease in the number of [condensed] configuration mitochondria due to fusion and necrosis, and an increase in the number of [orthodox] configuration mitochondria due to fragmentation