Self-reinforced polylactide/polyglycolide 80/20 screws take more than 1(1/2) years to resorb in rabbit cranial bone

The aim of this study was to assess tissue reactions to bioabsorbable self-reinforced polylactide/polyglycolide (SR-PLGA) 80/20 miniscrews in rabbit cranial bone. One PLGA screw was implanted on one side and one titanium screw on the other side of the sagittal suture (n = 21). Three animals were sacrificed after 2, 4, 8, 16, 24, 54, and 72 weeks. In histological examination the numbers of macrophages, giant cells, active osteoblasts, and fibrous tissue layers were assessed and degradation of the bioabsorbable screws was evaluated. After 2 weeks, macrophages were seen near the heads of both screws. After 4 and 8 weeks, the bioabsorbable screws were surrounded by fibrous tissue. Osteoblastic activity and groups of several giant cells were seen. After 24 weeks, a significant change in the morphology of the PLGA screws had occurred. Osteoblastic activity and the amount of giant cells had decreased. After 1 year, some PLGA biomaterial was still present. PLGA screws had been replaced by adipose tissue, fibrous tissue, and "foamy macrophages" that had PLGA particles inside them. After 1(1/2) years, the amount of biomaterial remaining had decreased remarkably. The particles of biomaterial were inside foamy macrophages. SR-PLGA 80/20 screws are biocompatible and have no clinically manifested complications when used in the cranial bone of rabbits. No contraindications as regards their clinical use in craniofacial surgery was found when these screws were studied in the cranial bones of rabbits.     

Electroconvulsive therapy in adolescent and adult psychiatric inpatients--a retrospective chart design

BACKGROUND: The knowledge available on electroconvulsive therapy (ECT) in adolescents is largely anecdotal, or based on findings from adults. The aim of the present study is to compare the use of ECT in adolescent and adult inpatients. METHODS: We retrospectively analyzed the files of all 36 adolescent (between the ages of 13 and 19) and 57 randomly selected adult inpatients (above the age of 20) treated with ECT in a university-affiliated mental heath center in Israel between 1991 and 1997. RESULTS: Sixty one percent of the adolescents improved by the end of treatment, and 53% were not hospitalized in the subsequent year. The respective percentages among adults were 83% and 49%. Whereas most adults were treated with ECT because of schizophrenic disorders, almost half of the adolescents received ECT for affective disorders. Significantly more adolescents were treated with ECT because of acute life-endangering conditions (catatonia or severe suicidal risk). No significant adverse effects were found in both groups. LIMITATIONS: Our study is based on a retrospective chart review. The adolescent and adult groups are different in psychiatric morbidity, diagnosis and outcome, have not been assessed in a blind manner, and we have not used standardized psychometric batteries for the evaluation of ECT-related memory disturbances. CONCLUSIONS: ECT may be an effective, well-tolerated and safe procedure in both adult and adolescent inpatients.     

Diffuse lymphocyte-predominant Hodgkin''s disease (diffuse paragranuloma). A variant of the B-cell-derived nodular type.

Lymph node sections from 10 cases of mixed nodular/diffuse and 10 cases of completely diffuse lymphocyte-predominant Hodgkin's disease (LPHD) were immunophenotyped. The results obtained were compared with those of nodular LPHD (nodular paragranuloma). In conventional stains, nodular/diffuse LPHD differed from diffuse LPHD in the presence of nodularity, which can be best demonstrated with silver impregnation. Immunohistologic analysis showed a correlation of the difference in nodularity with the presence or absence and pattern of follicular dendritic cell (FDC) meshwork, ie, a relatively sharply defined and large spherical meshwork was present in nodular areas of nodular/diffuse LPHD, whereas FDCs were either absent or present in a diffuse, ill-defined meshwork, usually of small size, in the diffuse zones of nodular/diffuse LPHD and in diffuse LPHD. The amount of FDC meshwork corresponded roughly to the number of reactive B cells and T cells, meaning that in diffuse areas significantly fewer B cells and more T cells were observed than in nodular areas. The immunohistologic analysis also showed that the antigen profile (positivity with the monoclonal B-cell marker L26 in the majority [14/20] of cases and negativity for CD15 in all but one of 20 cases) of the tumor cells in both nodular/diffuse LPHD and diffuse LPHD were comparable while it was different from the antigen profile (L26- and CD15+) in most cases of nodular sclerosis and mixed cellularity types of HD. This suggests that the considered subtypes of LPHD differ mainly in FDC pattern, but not in origin and nature of the tumor cells. This further justifies assignment of the above-mentioned LPHD subtypes to the category paragranuloma (LPHD).     

Pro-megakaryoblasts in bone marrow tissue from patients with primary (idiopathic) osteo-myelofibrosis (agnogenic myeloid metaplasia). An immunomorphometric study on trephine biopsies

An immunomorphometric study was performed on bone marrow biopsies from 40 patients with primary osteomyelofibrosis--OMF, (agnogenic myeloid metaplasia) by employment of a monoclonal antibody against glycoprotein IIIa (Y2/51) to determine the number of pro-megakaryoblasts. Specimens from 15 individuals without any hematological disorder served as controls. With reference to the pertinent literature on megakaryocyte precursors and following a pilot study on corresponding smears, in tissue sections pro-megakaryoblasts were characterized by a size of 42.1 +/- 2.6 microns 2 (diameter 7.5 +/- 0.3 microns). In comparison with controls, in OMF no relevant increase in the number of pro-megakaryoblasts per square and cubic millimeter bone marrow was evaluable. The relative frequency of these precursors was significantly reduced due to an increase in the total amount of conspicuously large and abnormal megakaryocytes. Statistical analysis failed to reveal any correlations between counts for pro-megakaryoblasts or the total number of Y2/51--positive megakaryocytic elements with the density of argyrophilic fibers (determined by morphometry) or the platelet values. Our findings imply that in OMF the marked increase in circulating progenitor cells of the megakaryocyte lineage may be generated by extramedullary, probably splenic hematopoiesis. Moreover, the evolution of medullary fibrosis is thought to be associated with the striking predominance of large atypical, possibly overaged and hyperpolyploid megakaryocytes and not with an increase in precursor cells.     

Temporal factors influence recovery of function after embryonic brain tissue transplants in adult rats with frontal cortex lesions

Adult rats with lesions of the medial frontal cortex received implants of frontal cortex taken from embryos on the 19th day of gestation and placed directly into the zone of injury at 7, 14, 30, or 60 days after initial surgery. Another group was given bilateral frontal lesions, followed 20 days later by a second small lesion to enhance the release of putative neurotrophic factors. They then received transplants 7 days after this second operation. All rats began postoperative training on a spatial alternation learning task within 4 days after the implants of fetal tissue. The brain-damaged rats with transplants at 7 or 14 days after surgery significantly improved postoperative acquisition of spatial alternation. Transplants made 30 or 60 days postoperatively had no effect; these groups were as impaired as those with lesions alone. The animals given a second, "priming" lesion after a 20-day delay, followed by implants of fetal brain tissue, performed as poorly as the group with frontal cortex lesions alone.     

Further investigation of the association between gastroesophageal reflux and bronchoconstriction

A double-blind modification of the intraesophageal acid perfusion challenge (Bernstein procedure) was performed in asthmatic subjects with and without gastroesophageal reflux, nonasthmatic subjects with reflux, and normal subjects. Conventional spirometric functions and total respiratory resistance (Rrs) were measured prior to and after the infusion. There were no changes in pulmonary functions except in the asthmatic subjects who had had a positive add challenge. The greatest changes occurred in Rrs, which increased significantly with reflux symptoms (p < 0.01) and decreased toward baseline (p < 0.05) when these symptoms were relieved with antacids. The response was even greater in asthmatic subjects who associated reflux symptoms with attacks of asthma. These results support previous findings that acid reflux symptoms could cause a bronchoconstrictive response in certain asthmatic patients.