The influence of gonadectomy of host on parasitemia and mortality of mice infected with Trypanosoma cruzi

Male CF1 mice were more susceptible to acute infections of Trypanosoma cruzi than female mice as evidenced by significantly greater maximum mean parasitemia of approximately 8.9 times 10-6 per ml in males as compared to 1.5 times 10-6 per ml in females. Mortality was also greater in males (80 to 90% as compared to 28% in females). Ovariectomy of female mice made them more susceptible than unoperated female of similar age and stock to the Brazil strain of T. cruzi as indicated by maximum mean parasitemia of 10.9 times 10-6 per ml in the former and 7.5 times 10-6 in the latter. Mortality of the ovariectomized mice was as great as 90% in some experiments while that of unoperated controls nerve exceeded 30%. Parasitemia and mortality is castrated male mice were not significantly different from unoperated male mice infected with T. cruzi.     

Cocaine-sensitive sigma-receptor and its interaction with steroid hormones in the human placental syncytiotrophoblast and in choriocarcinoma cells

The expression and ligand binding characteristics of sigma-receptors in human placental syncytiotrophoblast and choriocarcinoma cells were investigated using haloperidol as a ligand. Haloperidol bound to purified placental brush border membranes with high affinity; the apparent dissociation constant for the process was about 3 nM. These binding sites were not related to dopamine (D2) and serotonin (5-HT2) receptors nor to serotonin and norepinephrine transporters. The ligands of sigma-receptors [3.g. (+)-3-(3-hydroxyphenyl)N-(1-propyl)piperidine, 1,3-di-(2-tolyl)guanidine, clorgyline, rimcazole, and dexromethorphan] were very potent in competing with haloperidol for the binding sites. The binding sites were detected not only in the brush border membrane, but also in intracellular membranes. The rank order of potency of various sigma-receptor ligands to inhibit haloperidol binding indicated that placental sigma-receptors belong to the sigma 1 subtype. Cocaine and its analog RTI-55 [2 beta-carbomethoxy-3 beta-(4-iodophenyl-) tropane] inhibited the binding of haloperidol to placental membranes with appreciable potency. The steroid hormones, progesterone and testosterone, were also potent inhibitors, and the inhibition constant for progesterone was 0.3 microM, a concentration much smaller than that found in plasma during pregnancy. The inhibition was competitive. beta-Estradiol and a number of other steroids were relatively much weaker inhibitors than progesterone and testosterone. Phenytoin and neuropeptide-Y did not interact with sigma-receptors in placenta. The choriocarcinoma cell line JAR was also found to express sigma-receptors in the plasma membrane as well as in intracellular membranes. The characteristics of the receptors in this cell were qualitatively similar to those of the receptors in normal placenta, including subtype identity and interaction with cocaine and progesterone. Interestingly, however, all sigma-receptor ligands interacted with the receptors in the JAR cell with much higher affinity than with the receptors in normal placenta. It is concluded that the placental syncytiotrophoblast and choriocarcinoma cells express cocaine-sensitive sigma-receptors and that progesterone is most likely an endogenous ligand for these receptors.     

Thermography in differential diagnosis of lymphostasis in the lower limbs]

The authors report the data concerning the use of lymphography and thermography with the purpose of establishing the differential diagnosis in 42 patients with edema of the lower limbs of a different origin. A comparative estimation of different methods of the differential diagnosis indicated the advantages of infra-red thermography.     

Functional changes after segmental and lobar resections of the lungs at remote periods of observation

Clinico-roentgenological and functional studies were carried out in 78 patients 2--12 years following segmental (42 patients) and lobar (3) pneumonectomies for tuberculosis. An analysis of the data obtained indicated that partial pneumonectomies within the boundaries of 1-5 segments per se fail to produce significant disorders in the ventilatory and gas metabolism function of the lung. 2-12 years after the operation the patients show considerable ventilatory reserves. Significant respiratory disorders are observed only in patients with postoperative complications and pathological changes in the lung, pleura and bronchi conditioned by tuberculosis and non-specific lung pathology.     

\text{ CO}_{2} Laser-Based Pulsed Photoacoustic Ammonia Detection

Detecting ammonia traces is relevant in health, manufacturing, and security areas, among others. As ammonia presents a strong absorption band (the $\nu _{2}$ mode) around 10  $\upmu $ m, some of the physical properties which may influence its detection by means of pulsed photoacoustic (PA) spectroscopy with a TEA $\text{ CO}_{2}$ laser have been studied. The characteristics of the ammonia molecule and the laser intensity may result in a nonlinear dependence of the PA signal amplitude on the laser fluence. Ammonia absorption can be described as a simple two-level system with power broadening. As $\text{ NH}_{3}$ is a polar molecule, it strongly undergoes adsorption phenomena in contact with different surfaces. Therefore, physical adsorption–desorption at the cell’s wall is studied. A theoretical model, based on Langmuir’s assumptions, fits well to the experimental results with stainless steel. Related to these studies, measurements led to the conclusion that, at the used fluenced values, dissociation by multiphotonic absorption at the 10P(32) laser line may be discarded. A calibration of the system was performed, and a detection limit around 190 ppb (at 224 $\text{ mJ}\cdot \text{ cm}^{-2}$ ) was achieved.