Conduction studies in peripheral cat nerve using implanted electrodes: III. The effects of prolonged constriction on the distal nerve segment

Electrophysiological properties were monitored in detail in chronically constricted peripheral nerves by implanted, multicontact nerve cuff electrodes and correlated with morphometric histology in selected cases. The physiological and histological responses in nerve to a range of constricting cuffs of standard sizes were readily graded. The initial response to any significant constriction was a transient, focal conduction slowing or block at the constriction, followed by more protracted distal effects; the latter ranged from loss of excitability consistent with "dying-back" degeneration to reductions in conduction velocity consistent with histologically observed atrophy. Smaller myelinated fibers tended to have similar but less pronounced changes than larger diameter fibers. Recordings from ventral and dorsal roots showed that distal degeneration was more pronounced in motor than in sensory fibers of similar caliber. Electronmicroscopical measurements showed that basal laminas were relatively preserved around even the most atrophic and demyelinated axons. Perimeter measurements of the basal lamina could be used to estimate the diameter of the original nerve fiber.     

Macular disease in related rhesus monkeys

During (January) 1986–(May) 1988, we examined 272 eyes in 136 rhesus monkeys in the closed Cayo Santiago colony of the Caribbean Primate Research Center of the University of Puerto Rico. Seventy-eight eyes were less than 10 years of age. One hundred and ninety-four were aged 10–28 years. The fundi were examined and photographed. Fluorescein angiography was performed in some eyes. Selected cases were evaluated for acuity loss by recording of pattern-evoked retinal and cortical signals. Light and electron microscopy were used to evaluate the pigment epithelium of some animals. Thirty-eight percent of all eyes had posterior pole drusen. Incidence was highly age-related. When late-stage lesions were found, we did not see neovascularization, but late hyperfluorescence was consistent with degenerative scarring and atrophy. Electrophysiology demonstrated moderately reduced acuity in the presence of numerous macular drusen. Electrooculograms were low normal. Histopathology showed changes identical to those reported in human age-related macular degeneration. No eyes less than 10 years of age had confluent drusen or disciform-like lesions. The incidence of drusen in samples of some social groups was much higher than others.     

Regulatory effects of biophysical strain on rat TMJ discs

Recent studies have revealed that dynamic biomechanical forces can exert antiinflammatory and antiproteolytic effects on fibrocartitage. Whether the effects of mechanical strain also involve stimulation of the insulin-like growth factor (IGF) system and, therefore, of growth and repair of fibrocartilage has yet to be determined. The objective of this in vitro study was to determine if continuous biophysical strain regulates the gene expression of IGF1, IGF2, IGF1 receptor (IGF1R), insulin receptor substrate (IRS1), and IGF-binding proteins (IGFBP) 3 and 5 in cells from the fibrocartilaginous disc of the temporomandibular joint (TMJ). Rat TMJ disc cells were subjected to continuous biophysical strain (3% and 20%) for 4 and 24 h. Subsequently, RNA was extracted and real-time PCR was performed using an iCycler iQ detection system to analyze the gene expression of the IGF system. The gene expression of IGF1, IGF2, IGF1R, IRS1, IGFBP3, and IGFBP5 was significantly (p < 0.05) inhibited when cells were subjected to continuous biophysical strain, as compared to control at both time points. High strain induced a stronger inhibition of these molecules as compared to strain of Low magnitude. In conclusion, continuous biophysical strain seems to downregulate the expression of the IGF system and may, therefore, reduce the potential of fibrocartilage for growth and repair.     

经皮穿刺椎间盘髓核摘除术入路的研究

为提供椎间盘髓核摘除术形态学依据，在7具成人横断面标本上观察测量了L1～L5椎间盘平面经皮穿刺椎间盘髓核摘除术的进针点、角度和深度。发现在L1～L3、L4～L5椎间盘髓核的穿刺点以距后正中线8～10cm，9～11cm，穿刺角度以46．7°～59．5°，穿刺深度为110．2～128．9mm为最宜。     

Methods for culture ofBombyx mori wing discs

Summary A culture method forBombyx wing discs is described. Grace's insect medium,Bombyx hemolymph, and moderate doses of ecdysterone (0.02 to 0.1 µg/ml) were necessary for complete imaginal differentiation ofBombyx wing discs. This procedure is useful for understanding ecdysteroid action on insect imaginal differentiation and metamorphosis.     

Morphometric analysis of the thoracic and lumbar spine in Japanese on the use of pedicle screws

The pedicle screw and hook have become popular instruments in treating spinal deformity and disease. This study gathered morphological data on thoracic and lumbar spines in a Japanese population that should serve as useful reference for posterior instrumentation surgery. One hundred and three dry bones were used to investigate the morphology of pedicle and facet in thoracic and lumbar spines. Measurements included the diameter and axial length of pedicle from T8 to L5, height and width of facets and thickness of articular processes from T1 to T12, and axial angle of pedicle from T1 to L5. The diameter and axial length of pedicle were smallest at T8, diameter was largest at L5 and axial length was largest at L3. Height of facets and thickness of articular processes were largest at T12. Men tended to have larger pedicles and facets than women. Transverse angle of pedicle was smallest at T12. These precise data may provide useful information when performing posterior instrumentation surgery and when developing new spinal implant systems for Asians.     

Disconnected optic axons persist in the visual pathway during regeneration of the retino-tectal projection in the frog

Summary In this study, we crushed one optic nerve in the frog Litoria (Hyla) moorei and at intervals thereafter anterogradely labelled optic axons with horseradish peroxidase (HRP). For one series, HRP was applied between the eye and the crush site and in a second series between the crush site and the chiasm. A tectal projection of regenerating axons was seen in both series but, in addition, up to 12 weeks post-crush, the second series displayed an additional projection. Its appearance matched that of the disconnected, but persisting, optic axon terminals which are found after enucleation or optic nerve ligation. We conclude that, in the frog, many disconnected optic axons persist throughout the period of optic nerve regeneration and of restoration of an orderly retino-tectal map.Abbreviation HRP horseradish peroxidase     

Differential effects of scopolamine on neuronal survival in ischemia and glutamate neurotoxicity: relationships to the excessive vulnerability of the dorsoseptal hippocampus

The neurodegeneration in the CA1 subfield of hippocampus exhibited a dorsal-ventral gradient of susceptibility in global ischemia (82% dorsoseptally and only 16% ventrotemporally). Scopolamine (SCOP) did not improve the neuronal damage caused by the global ischemic challenge in rats and did not reduce the infarct area after the focal MCA-occlusion in mice. No differences were observed between saline and SCOP-treated animals in the physiologic parameters, except for a slight increase in rectal temperature. In contrast, treatment of hippocampal cultures with increasing concentrations of SCOP (1 nM to 1 mM) under glutamate incubation had a beneficial effect on neuronal viability. These data show that (1) there is substantial gradient of vulnerability of the hippocampus from dorsal to ventral in global ischemia and (2) that interactions between the NMDA, muscarinic receptors and their corresponding neurotransmitter inputs to hippocampal neurons are evident in vitro and may play a crucial role in neuronal neurodegeneration. However, the mechanisms underlying the high vulnerability of dorsal hippocampus still remain enigmatic.     

Pigmentary degeneration indwed by N-methyl-N-nitrosourea and the fate of pigment epithelial cells in the rat retina

Pigmentary degeneration of the retina was induced by a single intraperitoneal Injection of 75mgkg of N-methyl-N-nitrosourea (MNU) In female Brown-Norway colored rats at 50 days of age, which were then observed at 24, 48 and 72 h and 7, 21,35 and 150 days after the treatment. MNU-treated rats showed selective destruction of the photoreceptor cells by an apoptotic mechanlsm 24 h after the treatment, and the destruction was completed by day 7. During the photoreceptor cell degeneration, proliferation of Miller cells and infiltratlon of macrophages was prominent 72h and 21 days aRttr the treatment, respectively. Müller cell proliferation and macrophage infiltratbn corresponded to degenerative photo-receptor cell phagocytosis, and prollferating Müller cell processes responded to stabilize the damaged retina. Pigment epithelial cell detachment from the Bruch's membrane was seen 72 h after the treatment, and migration within all layers of the retina was seen at day 7 when photoreceptor Cells were lost. At 21, 35 and 150 days after the treatment, lack of photoreceptor cells and deposition of pigment epithelial cells within the retina but not in contact to vascular endothe-lial cells were characteristic. MNU-induced photoreceptor apoptosis followed by Miiller cell and macrophage reaction then pigment epithellal cells deposition withln the retina partially resembles retinitis pigmentosa in humans.     

肝脏特异性表达载体Kbpala/Alb-ATP7B 的构建及表达

目的：构建小鼠白蛋白启动子引导下携带野 生及常见突变型Arg778Leu、His1069Gln的人ATP7B cDNA的肝脏特异 性表达载体Kbpala/Alb-ATP7B，并检测其表达情况。方法:定点突变法获取人群中常见的Arg778Leu及His1069Gln两种ATP7B突变体，定向克隆将小鼠白蛋白启动子Alb序列及野生和突变的ATP7B cDNA依次亚克隆至转基因载体Kbpala上，得到可在肝脏特异性表达的正常及突变型人 ATP7B的转基因载体Kbpala/Alb-ATP7B。将其 短暂转染BRL细胞及BHK细胞，通过Western blotting检测其蛋白表达情况。结果:经酶切鉴定及定点测序证实，转基因载体Kbpala/Alb-ATP7B 构建成功；Western blotting显示仅在肝脏细胞实现表达。结论:带 有人类ATP7B cDNA的野生及常见致病突变型的转基因载体Kbpala/Alb -ATP7B构建成功并在肝脏细胞特异性表达。