Ultrastructural changes in the gracile nucleus of the rat after sciatic nerve transection

Summary Ultrastructural changes in the gracile nucleus of the rat have been examined after peripheral nerve injury. The sciatic nerve of adult rats was transected at mid-thigh level, and after survival times ranging from 1 day to 32 weeks sections from the gracile nucleus were prepared for electron microscopic examination. Unoperated animals served as controls. Atypical profiles were regularly observed in the experimental cases at post-operative survival times from 3 days up to 32 weeks. It was sometimes not possible to classify these as pre-terminal axons or terminals, because synaptic contacts could not be identified. The two most common changes throughout the entire post-operative period were greatly expanded myelinated axons, or unmyelinated profiles containing numerous mitochondria, osmiophilic dense bodies and vacuoles. Atypical profiles were occasionally observed in unoperated control animals. The results clearly show that various types of degenerative changes occur in the gracile nucleus after peripheral nerve injury. These changes differ markedly from previously described transganglionic changes in other systems. It cannot be excluded that some of the changes reflect growth-related reactions, although the typical features of axon regeneration could not be found.     

Stress protection by external fixation of the rabbit tibia

Osteopenia of the tibia and femur caused by an external fixator in the tibia was studied in 14 rabbits. Eight rabbits were treated with a complete unilateral external fixator in one tibia, whereas the other tibia served as a control. The other 6 animals had one leg operated on with inserting of all the pins but without the frame. This technique was chosen to compare osteopenia caused by stress protection and the effect of the pins. After 6 weeks, we found a 7 percent reduction in the bone mineral content in the tibial diaphyseal segment between the pins of the external fixator and no bone loss in the tibia that were operated on with only pins. In the femurs, there was a smaller decrease in the bone mineral content: respectively 3.2 percent (complete frame) and 2.9 percent (only pins). On all the operated on tibiae, there was an increase in the bone mineral content around the pins both proximally and distally.     

DEVELOPING PERCEPTIONS OF TEMPERAMENT AND THEIR CHILDREN TO MOTHER AND INFANT BEHAVIOR

Controversies about temperamental assessments raise questions about whether questionnaires, which assess parental perceptions of temperament, validly measure within-child characteristics. Thirty-eight couples were recruited from childbirth classes for a short-term longitudinal study. Mother's perceptions of activity, rhythmicity and mood were moderately stable from late pregnancy to 6 mth postnatally. Only father's perceptions of activity were stable during this time. Infants rated by parents as difficult on the Carey Infant Temperament Questionnaire at 6 mth were rated by observers as less responsive while being fed by their mothers. Results are discussed in the context of influences on parental perceptions of temperament.     

3,4-DGE in peritoneal dialysis fluids cannot be found in plasma after infusion into the peritoneal cavity.

OBJECTIVE: Glucose degradation products (GDPs) are important in the outcome of peritoneal dialysis (PD) treatment. 3,4-dideoxyglucosone-3-ene (3,4-DGE) is the most cytotoxic GDP found in conventionally manufactured fluids and may, in addition, be recruited from 3-deoxyglucosone (3-DG). It is not known what happens with those GDPs in patients during PD. The aim of this study was to investigate if the 3,4-DGE and 3-DG in PD fluids can be found in plasma during treatment. DESIGN: PD patients were dialyzed with a conventional PD fluid containing 43 micromol/L 3,4-DGE and 281 micromol/L 3-DG. Parallel experiments were performed in rats as well as in vitro with human plasma. The rats were dialyzed with a PD fluid containing 100 micromol/L 3,4-DGE and 200 micromol/L 3-DG. RESULTS: The concentration of 3,4-DGE in the peritoneum decreased at a much higher rate than 3-DG during the dwell. 3,4-DGE was not, however, detected in the plasma of patients or rats during dialysis. The concentration of 3-DG in plasma peaked shortly after infusion of the fluid to the peritoneal cavity. The concentration of 3,4-DGE during experimental incubation in plasma decreased rapidly, while the concentration of 3-DG decreased only 10% as rapidly or less. CONCLUSION: 3,4-DGE could not be detected in plasma from either PD patients or rats during dialysis. This is presumably due to its high reactivity. 3-DG may, on the other hand, pass through the membrane and be detected in the blood.     

Clinical importance of confirming or excluding the diagnosis of chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) is a major complication of allogeneic hematopoietic cell transplantation. The presentation of this disease is varied, and it requires histological confirmation for diagnosis. In addition, cGVHD can often mimic other diseases, and vice versa. We have conducted a retrospective analysis of 123 patients referred to the GVHD clinic at the Johns Hopkins Oncology Center from 1994 to 1998 with a diagnosis of active cGVHD. Of these, nine patients (7%) had no evidence of cGVHD, and 25 patients (20%) had inactive cGVHD. Many of these patients were found to have other processes accounting for their ongoing symptoms. We conclude that since the therapy for this disease has significant toxicities and since what appears to represent cGVHD may actually be another disease, correct diagnosis of cGVHD or exclusion of this diagnosis is essential.     

Headache and dysfunction of the masticatory system in adolescents

An epidemiologic group of 285 17-year-old adolescents was studied with the aid of a questionnaire for frequency and intensity of headache and for symptoms of dysfunction of the masticatory system. They were also subjected to a functional examination of the masticatory system. Recurrent headaches occurred significantly more often among the girls (18%) than the boys (6%). Girls also reported significantly more intense headaches than boys. Fatigue in the jaws and difficulties in chewing were commoner in those with frequent and more intensive headaches. Tenderness to palpation of the masticatory muscles and impaired mandibular mobility were significantly commoner findings among those with recurrent headaches and those with more intense headaches. Tooth-grinding and clenching were related to frequency but not to intensity of headache. The investigation showed a significant relationship between frequency and intensity of headaches and signs and symptoms of dysfunction of the masticatory system.