Prognosis of fracture of the talus in children: 21 (7-34)-year follow-up of 14 cases

14 children suffering from a fracture of the talar neck or body were examined after 21 (7-34) years. The talar neck was fractured in 10 children and the talar body in 4. 3 fractures were displaced and primarily treated with reduction and immobilization. Nondisplaced fractures were treated conservatively. All fractures healed. All patients with displaced fractures had exercise-induced pain at follow-up. Of 11 patients with nondisplaced fractures only 1 had minor complaints.

CT and conventional radiographs showed arthrosis in the talocrural joint and normal subtalar joints in those with displaced fractures. The radio- graphic findings were normal after nondisplaced fractures.     

RBC improved survival due to recombinant human erythropoietin explains effectiveness of less frequent, low dose subcutaneous therapy.

Effectiveness of less frequent, once weekly, low dose subcutaneous recombinant human erythropoietin (rHuEPO) in maintaining 35% hematocrit in patients with chronic renal failure, predialysis and ESRD receiving dialysis, is dependent on rHuEPO induced prolonged RBC survival. One year of weekly rHuEPO doses to 7 patients originally part of the National Cooperative Protocol were evaluated for a total of 372 weeks for an average of 53 weeks per patient. The original 8 to 12 week dosage was directed by protocol for units per dose at 3 doses per week (4 IV, 3 subcutaneous). Thereafter, all doses were subcutaneous. Units/dose and doses/week were titrated to keep hematocrit at 35-38%. Dosage reduction of rHuEPO was determined by two investigators at the time of each examination. Statistical correlation was performed on effect of rHuEPO on 51Cr T1/2 RBC survival changes and changes of rHuEPO weekly doses. Patients evaluated at specific time points in the study were compared to themselves as their own controls by paired t-test analysis. The long-term increased RBC count correlated with prolonged RBC survival by 51Cr T1/2 rather than reticulocytosis. A relatively increased ease of sustaining the target hematocrit of 35% was demonstrated from the 8th week to 1 year. Thirty-two percent of the expanded RBC mass was older at 12 weeks and 22% was older at 1 year. rHuEPO dosage was reduced to 27% at weeks 8-12, to 21% at weeks 20-24, and to 38% at 1 year corresponding to prolonged RBC survival. 51Cr T1/2 increased from 21.6 days control to 28.6 days at 12 weeks and 26.3 days at 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pancreatoblastoma--histopathological and ultrastructural analysis of two cases.

Pancreatoblastoma has been described in children and characterized by unique histologic features and excellent clinical course. Ultrastructural and immunohistochemical studies of pancreatoblastoma reveal either exocrine alone or both endocrine and exocrine differentiation. We present two cases of pancreatoblastoma in children in which immunohistochemical and ultrastructural examination failed to demonstrate features of either enzyme or hormone production and which became worse in clinical course. We assume that pancreatoblastomas are tumors which differentiate more toward acinar or ductal elements than toward islet cell.     

Glutamate-induced calcium signaling in astrocytes

Astrocytes respond to the excitatory neurotransmitter glutamate with dynamic spatio-temporal changes in intracellular calcium [Ca²⁺]_i. Although they share a common wave-like appearance, the different [Ca²⁺]_i changes--an initial spike, sustained elevation, oscillatory intracellular waves, and regenerative intercellular waves--are actually separate and distinct phenomena. These separate components of the astrocytic Ca²⁺ response appear to be generated by two different signal transduction pathways. The metabotropic response evokes an initial spatial Ca²⁺ spike that can propagate rapidly from cell to cell and appears to involve IP₃. The metabotropic response can also produce oscillatory intracellular waves of various amplitudes and frequencies that propagate within cells and are sustained only in the presence of external Ca²⁺. The ionotropic response, however, evokes a sustained elevation in [Ca²⁺]_i associated with receptor-mediated Na⁺ and Ca²⁺ influx, depolarization, and voltage-dependent Ca²⁺ influx. In addition, the ionotropic response can lead to regenerative intercellular waves that propagate smoothly and nondecrementally from cell to cell, possibly involving Na⁺/Ca²⁺ exchange. All these astrocytic [Ca²⁺]_i changes tend to appear wave-like, traveling from region to region as a transient rise in [Ca²⁺]_i. Nevertheless, as our understanding of the cellular events that underlie these [Ca²⁺]_i changes grows, it becomes increasingly clear that glutamate-induced Ca²⁺ signaling is a composite of separate and distinct phenomena, which may be distinguished not based on appearance alone, but rather on their underlying mechanisms. © 1994 Wiley-Liss, Inc.     

Pharmacological study of the chicken's monocular optokinetic nystagmus: effects of GABAergic agonist and antagonists.

When injected into the chicken open eye, the GABA-agonist THIP and the GABA-antagonists bicuculline and picrotoxin induced spontaneous eye movements in nasal-temporal (N-T) and in temporal-nasal (T-N) direction, respectively. These spontaneous movements were scarcely modulated by optokinetic stimulation, irrespective of the direction of stimulation. It is suggested that they are due to the suppression of directional selectivity of retinal ganglion cells. When injected into the closed eye, GABAergic drugs did not produce spontaneous nystagmus. THIP provoked a reduction of the N-T component, without modifying the T-N one, while GABA antagonists induced a significant increase in OKN performance, especially for the N-T direction of stimulation. In these conditions, picrotoxin also provoked an increase in the duration of both components of optokinetic after nystagmus, indicating a direct effect of the drug upon the velocity-storage system.