Growth in culture of the peripheral axons of the spiral neurons in response to displacement of the receptors

Summary Observations were made on the growth of the peripheral axons of the spiral neurons in injured explants of the cochlea of the mouse. Opening of the cochlear duct during explantation usually results in a displacement of the hair cells into the outgrowth zone if the basilar membrane of the excised organ of Corti faces the substrate.Spiral neurons respond with vigorous growth to the stress created by the displacement of their receptors. Two different growth reactions occur in succession: 1) growth by elongation of the synaptically engaged fibre 2) free growth.The response of the neuron to an incipient displacement of the hair cells is an elongation of the fibre while its contacts with the receptors are, at least partly, preserved. Most or all fibres that are connected with the displaced cells elongate. The growth is well organized, limited to the region of the displaced hair cells, and restricted in length by the position of the receptors. It is inferred that tension on the synaptically engaged fibre may be a stimulus for its growth and that the growth ceases when the tension is relieved.Continuous stress eventually leads to a rupture of the fibre. The break usually occurs near or at the terminals, leaving the terminals attached to the hair cells. The proximal end of the fibre — now free — starts to grow. The growth is independent of the receptors, unrestricted in length, uncontrolled in amount, and continues for at least three weeks after explantation. The path of the fibre is tortuous, and collaterals are often emitted. Free growth proceeds at a markedly faster rate than growth by elongation.Maintenance of the synapse and growth of the fibre seem to be mutually dependent events. A peripheral axon of the spiral neuron can sustain in culture a normal innervation pattern, without any obvious signs of abnormal growth, if its connections with the hair cells are undisturbed; it elongates in an organized manner, if these connections come under stress; it responds with an uninhibited growth if the connections are broken.     

Patients’ experiences of dialysis services: are national health strategy targets being met?

Background The National Health Strategy envisages a health system incorporating patient views; and providing accessible, consultant-led dialysis services with patient choice of dialysis modality, in all regions. Aims To describe patients’ experiences of renal services against National Health Strategy objectives. Methods Telephone interviews with 192 dialysis patients from three hospitals in the Eastern region. Results One-quarter of participants (16% of haemodialysis [HD] and 46% of peritoneal dialysis patients) lived outside the Eastern region, and travelled there because dialysis was not available locally. Two-thirds (65%) had a choice of dialysis modality. High satisfaction with interpersonal care was observed (83–98% satisfaction). Dissatisfaction with physical environment included parking (39–56%), waiting areas (62–69%), HD unit space (74%). Regarding support services, dietary services were satisfactory (92–95%), with lower satisfaction ratings for social and financial support services (62%). Conclusions Structural and management issues must be addressed to advance a quality agenda for renal care in Ireland.     

Health and health care utilisation among asylum seekers and refugees in the Netherlands: design of a study

Background  

This article discusses the design of a study on the prevalence of health problems (both physical and mental) and the utilisation of health care services among asylum seekers and refugees in the Netherlands, including factors that may be related to their health and their utilisation of these services.     

半肢骨骺发育异常1例

１　病例报告　男,７岁．因双下肢不等长,右膝及右踝关节骨性肿大就诊．无明显外伤史,亦无红、肿、热、痛病史．查体：发育正常,营养良好．双下肢不等长,左６０ｃｍ,右６４ｃｍ,有跛行．右膝及右踝内侧肿大,肤色正常,关节活动无异常．Ｘ线：右侧半身诸关节（肩、肘、腕、髋、膝、踝）骨骺及干骺发育均较左侧增大,肢体较长,骨骺出现亦较对侧提早．如右尺骨茎突骨骺较左侧提早出现（图１）．右肘关节肱骨小头骨骺较左侧增大（图２）．右髋臼发育浅平,边缘毛糙,右股骨头骨骺较左侧明显增大,其距泪滴之距离较左侧大１．０ｃｍ,呈…     

丁公藤碱Ⅱ类似物的合成及其生物活性

本文设计合成了丁公藤碱Ⅱ的C_2脱氧和C_8电子等排类似物。药理结果表明,丁公藤碱Ⅱ的C_2羟基是保持其缩瞳活性的关键部分之一;目的物2和4各自分别具有拟和抗胆碱活性;电子等排目的物16和17既无拟也无抗胆碱作用。     

GABA-like immunoreactivity in the cochlea of the developing mouse

Summary GABA-like immunoreactivity was studied in surface preparations of cochleas from postnatal developing mice, and GAD-like immunoreactivity was studied in the adult. GABA-positive fibres are already present at birth; they innervate both the inner and outer hair cells and some spiral ganglion cells. The GABA-positive fibres that enter via the intraganglionic bundle send collaterals to the spiral ganglion and to the hair cell region. Fibres that enter along the central processes of spiral neurons end predominantly among the spiral ganglion cells. A few spiral neurons display pericellular rings of GABA-positive boutons at birth. In older animals, the endings occur on a small number of spiral ganglion cells either as rings or as brush formations. The early GABA-positive fibres reach the inner hair cells around the second day and the outer hair cells (of the upper turns only) around the seventh day. In 12-day animals, tunnel fibres arborize in the outer hair cell region; their collaterals make contacts with the outer hair cells within four to eight cell-wide segments, distributing the endings high, up to the reticular plate. In older animals, fibres (both GABA- and GAD-positive) may innervate single vertical rows of outer hair cells. In the maturing and the adult cochlea, the GABA-positive component of the inner spiral bundle is conspicuous and extends along the entire cochlear length, but the innervation of the outer hair cells comprises only the mid and apical turns.GABA-positive nerve cells occur among the small vestibular neurons, occasionally among the cells of eighth nerve nucleus and only exceptionally in the spiral ganglion. In the adult animal, GAD-positive cells, although uncommon, were observed among the spiral neurons.In the developing animal, GABA-positive fibres give rise to transitory formations: (1) a convoluted plexus running beneath and among the radial bundles and (2) a sparse plexus, continuous with the inner spiral bundle and running in the upper plane of the inner spiral sulcus. GABA-like immunoreactivity was also observed in neuronal growth cones and in some fibres running along blood vessels.In conclusion, GABA immunoreactive fibres appear to reach the cochlea by two routes: via the intraganglionic bundle and to a much lesser extent via the central bundles of the spiral ganglion. The fibres innervate sensory cells and also some spiral neurons. The occasional presence of GABA-positive neurons in the vestibular ganglion, in the VIIIth nerve nucleus, and exceptionally among the spiral neurons raises the possibility of a local GABAergic circuitry within the inner ear.     

Comorbidity,limitations in activities and pain in patients with osteoarthritis of the hip or knee

Background  

This study aims to contribute to the knowledge of the influence of comorbidity in OA. The objectives of the study were (i) to describe the prevalence of comorbidity and (ii) to describe the relationship between comorbidity (morbidity count, severity and the presence of specific diseases) and limitations in activities and pain in elderly patients with knee or hip OA using a comprehensive inventory of comorbidity.