Electron microscopic immunocytochemical study of somatostatin neurons in the periventricular nucleus of the rat hypothalamus with special reference to their relationships with homologous neuronal processes

The neurons containing somatostatin in the rat periventricular nucleus were studied by using a modified electron microscopic immunocytochemical technique that improves both the penetration of immunoreagents into unembedded immunostained tissues and the preservation of ultrastructural morphology. Inside perikarya and dendrites, immunostaining was not only associated with neurosecretory granules but also with ribosomes and saccules of the cis face of the Golgi apparatus. In the axonal profiles found in this region the labeling was observed both on neurosecretory granule cores and on the limiting membrane of small synaptic-like vesicles. Throughout the periventricular nucleus, both non-synaptic and synaptic relationships were shown between labeled neurons. Non-synaptic relationships mainly consisted of direct apposition of the membranes of neighboring neurons by dendrosomatic, somasomatic or dendrodendritic contacts. These labeled perikarya and dendrites were also synaptically contacted by labeled axonal endings containing numerous aggregated synaptic-like vesicles. The physiological significance of the synaptic and non-synaptic relationships between somatostatinergic neurons is discussed in terms of possible synchronization between homologous neurons of the somatostatin neuroendocrine system and control of these neurons by a central ultra-short loop feedback mechanism.     

牛骨羟基磷灰石复合游离骨膜肌肉内植入成骨的计量研究

观察牛骨羟基磷灰石和游离骨膜的异位成骨效应。牛骨羟基磷灰石Ｂｉｏ－ｏｓｓ单独或复合游离骨膜植入家兔腓肠肌内。３周和６周时制备不脱钙标本作组织学检查及计量学分析。结果：复合骨膜植入标本在５天以后开始产生新骨，３周时，新骨面积占标本截面的（１９．０±５）％，６周时为（２３．５±６）％。单纯肌内植入羟基磷灰石或骨膜均无新骨形成。全部植入标本内均未见炎性和排斥反应。证明，牛骨羟基磷灰石具有良好的传导成骨性能，复合骨膜植入肌内可产生新骨。     

Results of flexor tendon repair of the hand by the motion-stable wire suture by Towfigh

We compared the motion-stable wire suture by Towfigh (MSWST) with a modified Kessler suture (MKS) by following up flexor tendon repairs (MSWST, n = 21/39 digits; MKS, n = 20/31 digits). For MSWST we found 31 (79.5%) “excellent”, 3 (7.7%) “good”, and 5 (12.8%) “fair” results, when using the scoring system of Buck-Gramcko. In 3 (14.3%) patients the MSWST had to be removed owing to local irritation. In a further 3 (14.3%) patients, this was done when secondary tenolysis was necessary. The latter was also performed in 4 (20.0%) patients in whom the MKS was used. Here we found 23 (74.2%) excellent, 7 (22.6%) good, and 1 (3.2%) fair result. The statistical evaluation of the data concerning the patients’ age, sex, the involved zone, the side, and the functional outcome did not reveal a significant difference (P < 0.05) between both groups and the chosen type of repair. The results of MSWST and MKS are similar, but MSWST allows early motion therapy without a splint or rubber-band protection. Received: 8 March 2000     

Temporal relationships between the circadian rhythmicity in plasma levels of pituitary hormones and in hypothalamic concentrations of releasing factors

Ovariectomized female rats were implanted with estradiol containing silastic implants to induce constant circulating levels of the steroid, and sacrificed every 2 h in order to determine neuroendocrine rhythms. Under these conditions, we observed very marked circadian fluctuations in the hypothalamic concentrations of corticotropin-releasing factor (CRF), luteinizing hormone-releasing hormone (LHRH) and thyrotropin-releasing hormone (TRH), and in plasma levels of adrenocorticotropin (ACTH), corticosterone, luteinizing hormone (LH) and prolactin; the amplitude of the prolactin cycle was in particular much higher than in non-chronically estrogenized animals. The daily variation in CRF, ACTH and corticosterone showed significant rank correlations. Changes in hypothalamic content of LHRH and TRH were biphasic; the increase observed during the light period was abruptly interrupted by a depletion episode, coincident with the period of maximal LH and prolactin secretion, respectively. The initial phase of ACTH, LH and prolactin increments occurred between 11.00 and 15.00 h, and was relatively well synchronized. The steepest rise in ACTH and prolactin occurred at the same time, and preceded that of LH by a constant lag of about 2 h. After that initial period, secretion kinetics of the three hormones followed an independent pattern. The data suggest that increased secretion of several hormones results from activation of neural mechanisms occurring within a limited period of the 24-hour cycle.     

Intrapelvic cementless component extraction with immediate triflange acetabular reconstruction using the retroperitoneal approach

Use of the retroperitoneal approach has been well documented and used for intrapelvic cemented components or cement masses. We report on a single stage revision hip arthroplasty that incorporates a retroperitoneal approach for safe removal of an extensively entrapped porous-coated acetabular component and modular femoral head followed by an immediate reconstruction using a triflange acetabular prosthesis via a posterior approach.