Energy balance in subcutaneous melanoma-bearing mice

Energy balance of control and melanoma-bearing mice was determined after 15 days of controlled food intake. Body and tumor energy contents were evaluated after preparing the materials for bomb calorimetry. Neither energy intake nor expenditure was different between control and melanoma mice. Body energy gain was lower in melanoma mice, but including tumor energy both groups had similar energy gain during the experimental period. It is concluded that a two-week skin melanoma did not seriously affect the energy balance of mice, and that tumor growth was achieved by utilizing body energy without promoting any increase in energy intake.

Imipramine binding to blood platelets and aggressive behavior in offenders, schizophrenics and normal volunteers.

The relationships between [3H]imipramine binding to blood platelets and manifestation of aggressive behavior was studied in three different groups of subjects. Arrested offenders displayed high imipramine binding compared to controls, with violent offenders exceeding their nonviolent counterparts. Hostile schizophrenic patients showed imipramine binding higher than nonhostile matched patients. In normal volunteers, on the other hand, no correlation between imipramine binding and scores of aggression was found. The results support the notion about the involvement of a neuronal serotonergic system in the regulation of aggressive behavior. The contribution of this biological factor is detectable in pathological manifestation of aggression but not in normal behavior.

[Immunization with an anti-Lewis a antibody]. / Imunização por um anticorpo anti-Lewis a.

A case of immunological sensitization for a natural and irregular anti-Lewis a antibody, is presented. Immuno-hematologic studies of blood and saliva, and identification of seric antibody through a panel of phenotype red cells, were made.

Induction of autolysis in Streptococcus faecium.

Autolysis of exponential-phase Streptococcus faecium cells was promoted by pretreating the bacteria (freezing-thawing; -70 degrees C) in Tris buffer, followed by incubation at 37 degrees C in the same buffer. The effect was dependent on Tris concentration. The pretreatment provoked ultrastructurally visible damage with extensive loss of K+ and leakage of UV-absorbing components. No autolysis was observed when the bacteria frozen-thawed in Tris were incubated in the presence of the autolysin inhibitor N-bromosuccinimide nor when they had been grown in the presence of chloramphenicol or tetracycline. Furthermore, two autolytic-defective mutants, EC31 and EC78, isolated from S. faecium, did not autolyse when frozen-thawed and incubated in Tris. Freezing-thawing in Tris, however, imparted extensive cell damage to the mutants and to the antibiotic-treated bacteria as well as considerable leakage of K+ and UV-absorbing materials. These observations indicate that the lysis of S. faecium reported above is due to the activity of the endogenous bacterial autolysin. Induction of autolysis of S. faecium by freezing-thawing was also observed, although to a lesser extent, when Tris was replaced by imidazole.

A turbidimetric and electron microscopic study of the effects of several parameters on the lysis of Streptococcus faecalis by lysozyme.

The lytic effect of lysozyme on Streptococcus faecalis ATCC 9790 was studied by spectrophotometry and electron microscopy and it was found to be highly dependent on the ionic strength of the suspending media and on the ratio lysozyme to bacterial cell mass. When 7.2 X 10(8) bacteria/mL are exposed to 0.4 mg/mL of lysozyme in media with low ionic strength, the enzyme is bound in great amounts, as deduced from protein determinations and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS--PAGE); the binding prevents bacteriolysis in spite of the removal of the cell wall. Extensive lysis of S. faecalis could be obtained by reducing the ratio of lysozyme to bacterial cell mass. Stabilization of S. faecalis by lysozyme was also observed when exponential phase cells incubated under conditions that promote spontaneous autolysis (incubation in 0.05 M tris(hydroxymethyl)aminomethane buffer, pH 8.0, ionic strength = 0.01675) do not lyse and do not leak material which absorbs at 260 nm when lysozyme was present at the highest concentration.