Corticostriatal mechanisms of behavior

This article presents the results of three series of experiments on cats, dogs, and lower primates, performed to investigate the structural, neurophysiological, and mediator mechanisms of the corticostriatal systems involved in the organization of behavior. Morphological studies of corticostriatal connections showed that along with the diffuse distribution of afferent terminals within the striatum, there were also elements of topical organization defined by anteroposterior and mediolateral gradients. Neurophysiological experiments on dogs and lower primates were used to study the spike activity of the prefrontal region of the cortex and the head of the caudate nucleus during training to conditioned first- and second-order reflexes and during the solution of complex problems involving delayed spatial selection. Studies demonstrated that while in dogs, most of the neurons recorded showed a transition to responses to the conditioned signal at a particular stage of carrying out a conditioned response, in monkeys all cells recorded showed specific responses at different periods of solving the task at all stages of the study. Neuropharmacological experiments on dogs showed that agents blocking glutamine receptors in the caudate nucleus had more pronounced effects at the phase of developing conditioned movement reflexes. Administration of these agents during the reflex reinforcement phase affected only the differentiation of inhibition. These results lead to the conclusion that the prefrontal area of the cortex and, to some extent, the caudate nuclei, act on incoming information specifying the current dominant need and the states of the external and internal environments, to carry out programmed actions and assess the results of these actions.     

The megakaryocyte-thrombocyte system

The megakaryocytic apparatus of bone marrow and platelets are discussed as a common system whose physiological purpose is to ensure hemostasis when the integrity of the vascular wall is impaired. The principle of operation of the megakaryocyte-platelet system is synthesis, accumulation, and organization of a potent hemostatic potential, its distribution and dispersal along the vascular bed, if inactive, and its new formation at the moment of and at the site of required hemostasis. At the same time in its early and late major functional performance, the elements of the system are stable-at the early stages of megakaryocytopoiesis to the extent to the appearance of a promegakaryocyte and at the stage of platelet hemostatic cork. At the intermediate stages-that of the mature megakaryocyte divided by demarcation membranes and that of reversible aggregation of platelets which have not lost their individuality, the elements of the system are in an unstable state that is ready for disintegration or in a state that does not exclude its possibilities. In the central phase of its existence, the system is in a disintegrated state and appears as proplatelets and platelets. The mechanism of the dispersal and combination of elements and hemostatic potential of the megakaryocyte platelet system serves the apparatus of structural and contractile proteins, which acts as its system-forming factor.     

The biochemical and clinical aspects of the participation of granulocytes and their proteinases in a vascular wall lesion

Some components of plasma and granulocyte proteolytic system, granulocyte activation degree were evaluated in 15 patients with nonspecific aortic arteritis (NAA) and 12 hereditary hypercholesterolemia (HHC) patients. Catepsin G activity in blood plasma of NAA and HHC patients was higher than in donors 8-9 and 6-fold, respectively (p < 0.001). Granulocyte collagenase activity, spontaneous NBT test values in them were higher than in donors 6 and 4-fold (p < 0.02 and p < 0.01, respectively), 2-fold (p < 0.005 and p < 0.001, respectively). The data obtained confirm the suggestion on the presence of an inflammatory component not only in pathogenesis of NAA, but also in HHC causation.     

Identification of amidated forms of GLP-1 in rat tissues using a highly sensitive radioimmunoassay

This study has determined long-term continuation rates of clients who attended clinics of the New Zealand Association of Natural Family Planning and became autonomous users. It has also identified factors which might influence the continuation of NFP use. A total of 509 female subjects, 452 of them with their male partners, were enrolled in the study at the beginning of clinic teaching. Once autonomous they were sent questionnaires at 6-monthly intervals for a period of 24 months. Time out was allowed for pregnancy. The number of female subjects entering the 2-year follow-up phase of the study was 406 (79.8%). Of these 164 completed 2 years of use with 102 (20% of study entrants) using NFP and 62 (12.2%) using fertility awareness in combination with a barrier method. Subjects for whom NFP was their first family planning method, who were Catholic or who gave religion as their reason for choosing NFP were more likely to continue long-term use. The majority of subjects (> 90%) were highly satisfied with NFP use, with the most common reasons for satisfaction being self-awareness, freedom from drugs, naturalness and effectiveness. The difficulties reported related to abstinence and cycle interpretation.     

Lack of association between falciparum malaria parasitemia and acute diarrhea in Nigerian children

It is widely believed that malaria causes diarrhea. Yet, national and international diarrheal diseases control programs are silent about the overlap between these two major public health problems that coexist in most tropical countries. To test the hypothesis that malaria is associated with diarrhea and to define the role of malaria in morbidity due to diarrhea, 522 children 6-60 months of age presenting with acute diarrhea to the Children's Emergency Ward of the University College Hospital in Ibadan, Nigeria were routinely screened by means of thin and thick blood films for malaria parasitemia. Controls, without diarrhea, were studied in parallel. Detailed clinical features were recorded for every patient. Sixty-eight (13%) of the 522 diarrhea patients screened had malaria parasitemia. Among the controls (who had similar distributions of admission temperature, hemoglobin types, glucose-6-phosphate dehydrogenase deficiency, and prior treatment with antimalarial drugs), parasitemia was not significantly different, occurring in 56 (17.9%) of 313. In the dry season, however, a significantly higher prevalence of parasitemia was observed among the control group (15.5%) than in the diarrhea group (7.0%) (P = 0.004). Parasitemia was significantly more common in the dehydrated diarrhea patients than their well-hydrated counterparts (25% of 56 versus 11% of 466; P < 0.005). There were no significant differences in admission temperature, the presence of vomiting, or the home use of oral rehydration fluids between the dehydrated and the well-hydrated subsets of diarrhea patients. Consideration of parasite densities did not alter any of the foregoing relationships. These data contradict the widely held view that diarrhea is a symptom of malaria or that malaria causes diarrhea. They do, however, provide support for examining blood smears at least in dehydrated children with diarrhea in malaria-endemic areas and giving immediate antimalarial therapy to those who have malaria parasitemia.