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Data obtained in our experiments indicate that the microwave sterilization system utilized may be considered as a practical and rapid method for decontaminating steel surgical instruments. For the tested organisms (7 Gram- and 2 Gram+ genera) a 3' exposure time to microwaves provides successful sterilization. Microwave irradiation also had a killing action against Bacillus subtilis spores. A study by SEM of microwave treated spores shows typical morphological alterations of spore surfaces.

The present work studies the possibility of inducing an alteration in the erythropoietic switchover from primitive to definitive red cells in the chicken embryo by means of Cytoarabine (Ara C). To this purpose two different concentrations of Ara C were injected into fertilized chicken eggs after 94 hours of incubation. Optical microscopy was used in the morphological analysis of the blood smears taken from treated and control embryos on the 7th and 8th day of incubation (state 30 and 33 in the Lillie Table). 1) Injection of Ara C 4.1 x 10(-5) M did not induce any significant differences in the hematological picture between treated embryos and the controls. 2) Injection of Ara C 4.1 x 10(-4) M revealed a delay in the erythropoietic switchover both at the 7th and 8th day of incubation. In fact, the peripheral blood of the treated embryos showed that in the treated embryos there was a more than 24 hour delay in erythropoietic maturation. This is indicated by an unusually high number of 1st generation erythrocytes in the peripheral blood. Moreover, the 2nd generation red cells are at a lower stage of cell differentiation than the controls.

The present work studies the ability of cytoarabine (Ara C) to modify temporal regulation of hemoglobin synthesis in chicken embryos. Thus different concentrations of Ara C were injected into fertilized chicken eggs after 94 hours of incubation. Blood samples were taken from both treated and control embryos on the 7th and 8th day of incubation. 1) Ara C 4.1 x 10(-3) M: embryo mortality is total and takes place upon injection. 2) Ara C 4.1 x 10(-5) M: no significant difference was seen between hemoglobin patterns in the treated and control embryos. 3) Ara C 4.1 x 10(-4) M: a delay of at least 24 hours in hemoglobin switch-over is seen in the treated embryos. In fact, at the 7th day adult hemoglobin fractions A and D have not yet appeared while, on the 8th day, embryonic fraction P is still present.

Microwave irradiation provides a rapid and effective method for sterilization of stainless steel scalpel blades or cover glasses contaminated by B. stearothermophilus. A study by SEM of vegetative forms showed that microwave irradiation induce a progressive series of alterations and finally the complete destruction of the microorganism. On the contrary there were no significant morphological variations of the spores after lethal irradiation by microwaves.

The morphology of differentiated and differentiating cells of the red and white series in Lutjanus herenbergi and in Lutjanus flaviflammus is described. Early stages of red and white blood cells may be found only in smears of hemopoietic organs. Polychromatic erythroblasts, myelocytes and lymphoblasts may also occasionally be found in blood smears. Mature blood cells may be found both in blood smears and in hemopoietic organs. Differential white cell counts seem to demonstrate that the granulocytic series elements are the most common leukocytes in blood smears. Almost all granulocytes may be classified in the first three Arneth classes. An analysis of hemopoietic organs in these species was also performed. It was found that the only organs carrying on a hemopoietic function are the kidney and the spleen. The kidney is essentially a site of granulocytic differentiation while the spleen is a lymphopoietic organ. An erythropoietic activity may generally be observed in the kidney although weak erythropoietic activity may at times be found in the spleen.

Vitamin A can transform, in vitro, keratinized, multilayered, non secretory epithelium of carcinoma of portio cervicis into a simple mucous-secreting epithelium in the 40% of explants. The different response of Vit. A action on carcinoma may be associated with a different sensibility to this substance.

It is known that a medium conditioned by erythrocytes (ECM) reduces 59Fe uptake into haem in hemopoietic cell cultures. In order to evaluate if the release of this factor in conditioned media is correlated with the whole erythrocyte surface, the same volume of packed erythrocytes of Mammals characterized by different MCV were incubated according to the method of Cole and Regan (1977). The influence of these conditioned media upon 59Fe uptake into haem in cultures of Guinea pig bone marrow cells was studied. Our results demonstrate that ECM of lamb erythrocytes (MCV = 28) caused a more marked depression of haem synthesis in vitro than ECM of calf (MCV = 34) and Guinea pig (MCV = 69) erythrocytes, and that this inhibitory effect is correlated to the MCV of considered erythrocytes.

By comparing human embrional gum fragments cultivated in vitro using the technique of Wolff and Haffen with adult gum fragments, the advantages of the fetal gum are evident; and this could serve as a point of departure for an analysis of the differentiation and the cytophysiology of this structure, which is still not very well known.