Connections of the bullfrog striatum: Efferent projections

Autoradiographic and degeneration techniques were used to describe striatal efferents in the bullfrog (Rana catesbeiana). Horseradish peroxidase (HRP) was then placed in the major terminal fields to reveal the striatal cells responsible for these projections. Except for the small ventral eminence of the lateral pallium immediately adjacent to the dorsal striatum, no pallial region receives a striatal projection. Most striatal efferents descend in the lateral forebrain bundle (LFB), passing through the anterior entopedun-cular nucleus, where one large fascicle decussates in the anterior commissure and innervates the contralateral anterior entopeduncular nucleus and caudal ventral striatum. A smaller fascicle exits the LFB to terminate in the ipsilateral lateral amygdala. The remaining efferents continue caudal in the LFB through the posterior entopeduncular nucleus, with sparse projections to the ventral thalamus, the adjacent preoptic areas, and the posterior tuberculum leaving the bundle at various points. At pretectal levels, some efferents leave the LFB to run dorsally, through the caudal pole of the central thalamic nucleus and into the posterior division of the lateral nucleus and the lateral portion of the posterior thalamic nucleus. Efferents also continue caudal, through the superficial tegmental cell groups (nucleus profundus mesencephali and superficial isthmal reticular nucleus) before turning dorsomedially into the ventral anterodorsal, lateral anteroventral, and rostral pole of the posterodorsal tegmental fields. A small superficial projection continues to isthmal levels but cannot be traced beyond. Tegmental HRP injections retrogradely fill cells in the dorsal and ventral striatum as well as nucleus accumbens and the anterior entopeduncular nucleus. Pretectal HRP injections fill cells only in the caudal ventral striatum and anterior entopeduncular nucleus. Anterior entopeduncular nucleus HRP injections fill numerous cells in all striatal divisions, but some of this filling may be due to interrupted fibers of passage. Thus the anuran striatum, which receives its major input from thalamic nuclei relaying tectal and toral input, can in turn influence the midbrain roof via several disynaptic pathways: through the anterior entopeduncular nucleus, pretectum, and tegmentum, all of which project directly to the tectum and torus (Wilczynski and Northcutt, ′77; Wilczynski, ′81). Additional trisynaptic routes through the anterior entopeduncular nucleus and its pretectal and tegmental connections parallel the striatal routes.     

The number of receptors for factor VII correlates with the ability of cultured cells to initiate coagulation

Previously, we showed that cells derived from nonvascular tissues initiate clotting primarily by markedly increasing the activity of coagulation factor VII. Cells derived from vascular tissue do not normally exhibit this property (tissue factor activity). In this study, we have characterized the relationship between the tissue factor activity of cultured cells derived from normal tissues and the number of receptors they possess for coagulation factor VII. Only cultured nonvascular cells expressed tissue factor activity or possessed receptors for 125I-factor VII. Fetal lung cells, the nonvascular tissue with the largest amount of procoagulant and tissue factor activity, possessed the most receptors for 125I-factor VII (880,000/cell). Bovine corneal endothelial cells, the nonvascular tissue possessing the fewest number of receptors (2,400/cell), had the least amount of procoagulant or tissue factor activity. The affinity of nonvascular cells for 125I- factor VII varied for the cells studied (Kd congruent to 1.3-90 X 10(- 10) M). Vascular cells expressed no tissue factor activity, nor did they bind 125I-factor VII. 125I-factor VII and unlabeled factor VII bound to cells had identical procoagulant activities. These results indicate that the ability of cultured cells to initiate coagulation may be regulated in part by the number of receptors they possess for factor VII.     

Peritoneal dialysis treatment in children and parental stress

The burden placed on the parents of a child in dialysis treatment can induce negative effects on the medical treatment and on the psychological development of the child. To identify which families are at risk, both parents of 14 out of 16 eligible patients in continuous ambulatory peritoneal dialysis (CAPD) answered an extensive questionnaire three times during one year. Large differences were found between the families with regard to the amount of stress experienced. Parents of older children (< 5 years) (and particularly parents of children with a failed transplantation) experienced significantly more stress. The nature of the stress was determined more by the psychological aspects than by the medical aspects of the treatment. Concern about the future contributed most to the stress experienced. Therefore, emotional support as well as practical help for families at risk is recommended.     

The geometry of triple-balloon dilation

Triple-balloon dilation (TBD) of a variety of luminal structures has been successfully, though infrequently, used. A mathematical model is presented for the selection of balloon sizes, and equations and tables are derived that allow the user to estimate more accurately the size of balloons needed for TBD of structures with large lumina. With TBD, an approximately circular lumen can be formed. Also, TBD allows smaller, higher-pressure balloons to be used instead of single, low-pressure, large balloons. However, multiple puncture sites may be required for TBD.