Modification of Rat Behavioral Reactions by Peptides Secreted by Olfactory Cortex Cells upon Their Tetanization

We studied neurotrophic properties of neuropeptide extracts from tetanized slices of the rat olfactory cortex. Two types of the extracts were studied, EP and ED, obtained from perfusates of the tetanized slices after long-term potentiation and from the slices after long-term depression, respectively. The effects of these two extracts were tested on rats using the open field and passive avoidance tests upon intranasal administration of the extracts (ca. 1 ng total protein). EP showed a neurotropic effect combined with a moderate sedative–hypnotic effect, while EP had obvious neurotropic and nootropic properties, affecting mainly the mechanisms of memory consolidation, and had an activating effect combined with a minor, delayed sedative effect. The functional significance of the secreted endogenous neuropeptides and the mechanisms of their effects are discussed.     

Dynamics of habituation in different cortical regions of the cat brain

The dynamics of habituation in the rostral part of the parietal association region and also in the first and second somatosensory areas was studied by the evoked potentials (EP) method in cats anesthetized with chloralose (80-90 mg/kg) and immobilized with flaxedil. During repeated stimulation of the splanchnic nerve brief habituation of EP developed in the cortex. It corresponded in its basic features to habituation observed in other sensory systems. On comparison of the rates of development of habituation in the primary and secondary projection zones of the splanchnic nerve in the cortex differences were found: habituation developed more rapidly in the secondary projection zones. The functional importance of this phenomenon is discussed.     

Prevalence of human papillomavirus infection,distribution of viral types and risk factors in cervical samples from human immunodeficiency virus-positive women attending three human immunodeficiency virus-acquired immune deficiency syndrome reference centres in northeastern Brazil

Human immunodeficiency virus (HIV)-positive patients have a greater prevalence of coinfection with human papillomavirus (HPV) is of high oncogenic risk. Indeed, the presence of the virus favours intraepithelial squamous cell lesion progression and may induce cancer. The aim of this study was to evaluate the prevalence of HPV infection, distribution of HPV types and risk factors among HIV-positive patients. Cervical samples from 450 HIV-positive patients were analysed with regard to oncotic cytology, colposcopy and HPV presence and type by means of polymerase chain reaction and sequencing. The results were analysed by comparing demographic data and data relating to HPV and HIV infection. The prevalence of HPV was 47.5%. Among the HPV-positive samples, 59% included viral types of high oncogenic risk. Multivariate analysis showed an association between HPV infection and the presence of cytological alterations (p = 0.003), age greater than or equal to 35 years (p = 0.002), number of partners greater than three (p = 0.002), CD4⁺ lymphocyte count < 200/mm³ (p = 0.041) and alcohol abuse (p = 0.004). Although high-risk HPV was present in the majority of the lesions studied, the low frequency of HPV 16 (3.3%), low occurrence of cervical lesions and preserved immunological state in most of the HIV-positive patients were factors that may explain the low occurrence of precancerous cervical lesions in this population.     

Electrophysiological analysis of the spectrum of the fibers of the lateral olfactory tract in rats in vitro

Total action potentials (AP) of lateral olfactory tract (LOT) have been studied on 200 um sections of olfactory cortex of rat brain. Over-threshold stimulation of a proximal end of LOT was accompanied by five waves at descending phase of AP. The increase in stimulation frequency from 1 to 3 to 10 Hz led to a decrease in amplitudes of all LOT AP components. The data obtained suggest that the composition of LOT fibers is heterogeneous.     

Kinetics of uranous iron and ferrous iron oxidation by thiobacillus ferrooxidans

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