Synaptic reorganization in the medial amygdaloid nucleus after lesion of the accessory olfactory bulb of adult rat. II. New synapse formation in the medial amygdaloid nucleus by fibers from the bed nucleus of the stria terminalis

The rearrangement of terminations from the bed nucleus of stria terminalis (BST) was examined in the medial amygdaloid nucleus (MAN) at 2 months following the lesion of the accessory olfactory bulb (AOB) using an electron microscopy and degeneration study. At 2 days following a BST lesion, the number of degenerating synapses was 0.7 ± 0.1 (mean±S.E.M.) per unit area (2500 μm² in the molecular layer, and 3/0 ± 0.3 in the cellular part. At 2 months after an AOB lesion, the degenerating synapses from the AOB had completely disappeared from the MAN. The BST was then lesioned at 2 months after the AOB lesion and, 2 days following this BST lesion, the degenerating synapses were counted in MAN. The numbers observed were 3.3 ± 0.6 per unit area in the molecular layer and 4.5 ± 0.4 in the cellular part. Therefore, the number of these degenerating synapses increased significantly within the molecular layer, though, in the cellular part the number of synapses was not significantly elevated over control. No differences in postsynaptic profiles (ratio of synapses on dendritic spine to dendritic shaft) were observed after the AOB lesion. These results indicate that the BST fibers formed new synapses in the molecular layer following the denervation of AOB fibers. The possibility of new synapse formation by other afferent fibers in addition to the AOB fibers is discussed as is the relationship between lesion induced synaptic reorganization and functional recovery after injury.     

Organization of intensive care units in Europe: lessons from the EPIC study

Objective: To study differences related to intensive care unit (ICU) structure and patient demography between the various countries of Western Europe. Design: Application of data collected by the European Prevalence of Infection in Intensive Care (EPIC) study, a one-day prevalence study. Setting: Voluntary participation of all Western European ICUs. A total of 1417 ICUs responded. Patients: All patients, older than 10 years of age, occupying a bed in the participating ICUs over a 24-h period. 10 038 patient case reports were submitted. Results: The study revealed important differences. In particular, there seems to be a north/south divide with fewer ICU beds and more severely ill patients in the south. The United Kingdom seemed more similar to southern European countries than to the north. Conclusion: While there are similarities between European countries, large differences still remain and are important to identify to enable us to work together to create a more uniform system of intensive care, which will in turn give more effective and efficient patient care. Received: 7 February 1997 Accepted 8 July 1997     

Effects of androgens and estrogens on the vasopressin and oxytocin innervation of the adult rat brain

Recently we reported that castration of rats eliminates vasopressin immunoreactivity in the lateral septum and other areas that appear to receive vasopressin innervation from the bed nucleus of the stria terminalis. Testosterone treatment counteracts this effect of castration. In the present study, we investigated whether this action of testosterone depends on its androgenic or estrogenic metabolites by treating long-term castrated rats with estradiol (E) and/or 5 alpha-dihydrotestosterone (DHT) or testosterone. The brains were then processed for immunocytochemistry or radioimmunoassay. DHT did not increase vasopressin staining in the lateral septum, although it fully restored the size of the seminal vesicles. E did restore the original fiber density, but individual fibers stained more weakly than in sham-operated males. Only treatment with both E and DHT fully restored the vasopressin innervation. This pattern was also reflected in the radioimmunoassay data. The vasopressin content of the lateral septum decreased about 90% after castration but was fully restored by either testosterone or E + DHT treatment. E alone, however, was only half as effective as E + DHT. The treatments had no effect on the oxytocin content of the septum, or on the vasopressin or oxytocin content of the dorsal vagal complex. The results suggest that E mediates most of the effects of testosterone on the vasopressin innervation of the lateral septum. DHT enhances the response to E but has little effect on its own.     

Effects of oxytocin microinjected into the central amygdaloid nucleus and bed nucleus of stria terminalis on maternal aggressive behavior in rats

The central effect of oxytocin (OT) on the aggressive behavior of lactating rats was studied. Female rats are more aggressive than nonlactating resident females, vigorously attacking conspecific intruder male or females. This behavior is considered important for pup protection against infanticide. The present work aimed to test the effects on maternal aggressive behavior of OT infused into the central amygdaloid nucleus (CeM) or bed nucleus of stria terminalis (BNST). The surgeries for bilateral cannula implantation were performed between the 2nd and 4th postpartum day. Three days after the surgery, saline or OT was infused and 5 min later a male intruder was placed in the home-cage and the behaviors were videotaped for 10 min. The frequency of the aggressive behaviors and the duration of locomotion during the aggressive behavior test were measured. The latency to retrieve the pups was also evaluated. The results showed that OT injected into CeM (10 and 20 ng/nucleus) decreased frequency of biting and frontal attack while in the BNST (10 and 20 ng/nucleus) decreased the frequency of biting. No significant change on retrieval activity was detected. OT in CeM and BNST has an inhibitory effect on the aggressive behavior of lactating female rats.     

Differential fos activation in virgin and lactating mice in response to an intruder

Lactating (L) mice display fierce aggression towards novel, male mice, while virgin (V) mice do not. This study compares patterns of brain activation in V and L mice in response to a novel intruder using immunohistochemical detection of Fos (Fos-IR). Animals were sampled 120 min after either a sham or real 10 min test with a male intruder. L mice were aggressive towards intruders, but V mice were not. In general, Fos-IR for both groups increased with exposure to an intruder, with L mice showing higher increases in Fos-IR than V mice. In only medial preoptic nucleus and ventral portion of bed nucleus of stria terminalis (BNST) was Fos-IR significantly increased in both groups with testing. In V mice, testing resulted in Fos-IR increases in an additional 10 regions examined that did not reach significance in L mice, including lateral septum, lateral and medial preoptic areas, and anterior hypothalamus. Fos-IR also increased with testing in nine regions unique to L mice, including the mitral and granular layers of accessory olfactory bulb, regions of the amygdala, dorsal BNST, and caudal portions of the hypothalamic attack area. These increases in Fos-IR with testing suggest alterations in the circuitry governing response to pheromonal cues and imply some commonalities between the circuitries governing maternal aggression and intermale aggression. These results support the hypothesis that pregnancy and lactation induce substantial changes in brain circuitry and function; changes that enable maternal defense of offspring by altering the neural response to an intruder male.     

Pseudorandom testing technique for the characterization of local hemodynamic control

Summary In order to investigate the low frequency properties of renal and femoral hemodynamic variables, pseudorandom testing techniques were used. The arterial flow of each bed, in separate experiments, was modulated by a low amplitude signal based on a pseudorandom binary sequence (PRBS) generated by digital computer.The cross-correlation functions between input flow and arterial pressure, venous pressure, and venous flow exhibit damped oscillations in all cases. These responses are parameterized in terms of a damping ratio () and an undamped natural frequency _n for a second order model. The parameters of the model are dependent upon the state of the bed as defined by mean arterial and venous pressures, mean flow through the bed, resistance, and oxygen consumption.The results of this study offer further insight into the dynamic low frequency autoregulation phenomenon for the renal and femoral beds of the dog.Supported by NIH Grant HE 11747.     

从部分贫困县住院分娩资料分析看农村地区围产保健对策

利用１９９６年在四川省和陕西省４个卫－Ⅵ项目县县乡两级医院,采用前瞻性研究方法收集的住院分娩资料,着重分析了产科床位使用率、产科接生工作负荷、产妇住院天数、剖腹产比例。结果显示：产科床位使用率不高,绝大多数医院都有５０％以上的产科床位日没有利用;接生工作负荷亦不高,各医院从事接生人员的１周平均接生数在０．５￣２．６之间;在一些乡卫生院产妇住院时间短,５０％以上的产妇住院不满１天;陕西的两县剖腹产比     

经食管床高位食管胃机械吻合在食管癌手术中的应用

目的：探索用新术式治疗食管中、下段癌和部分上段癌的可行性。方法：本组全部经左胸第五肋间后外侧切口剖胸。用国产弯管形吻合器经食管床作食管胃端侧吻合。吻合部位在主动脉弓上、胸顶或颈根部(超胸顶)。在主动脉弓下折叠缝合胸胃小弯侧，使成直径4cm～5cm的管状。结果：本组共103例，有102例一次吻合成功。96例作主动脉弓上或胸顶吻合，7例作颈根部吻合。全组切缘均阴性，无吻合口瘘、狭窄及胃梗阻，无手术死亡。胸胃经食管床距离短，可最大限度的切除有癌灶的食管；吻合口和幽门区张力小，可减少吻合口瘘和幽门痉挛。胸胃在食管床内，可减少创面渗出，减轻对心肺压迫，减轻返流。由胸内游离颈根部食管，可减少喉返神经损伤的机会，不作颈部切口。结论：此术式融合了食管胃机械吻合、经食管床、缩小胸胃，经胸作颈根部吻合多个术式的优点，提高了患者生活质量，适用于大部分食管中、下段癌及部分胸上段癌患者。     

省级妇幼保健机构床位配置现状及其床位利用效率的综合评价

目的:通过对开展住院服务的省级妇幼保健机构的床位配置与床位利用情况的调查,对省级妇幼保健机构的床位配置现状进行分析,并利用秩和比法(RSR)对省级妇幼保健机构床位利用效率进行综合评价。方法:基于现代化的网络传输系统开发《全国妇幼卫生机构管理信息网络报告系统》,实现信息网络实时直报。结果:17所省级妇幼保健机构平均实有床位为171.1张,人均实有床位0.5张,即两名职工负担1张床位。根据床位利用效率综合评价结果将17所妇幼保健机构分为上中下3档,分别有6所、6所、5所机构。结论:大部分省级妇幼保健机构床位设置比较合理,床位利用效率较高。但是,少数经济落后地区的机构病床利用效率相对较低。     

Neurophysiological adaptations to spaceflight and simulated microgravity

Changes in physiological functions after spaceflight and simulated spaceflight involve several mechanisms. Microgravity is one of them and it can be partially reproduced with models, such as head down bed rest (HDBR). Yet, only a few studies have investigated in detail the complexity of neurophysiological systems and their integration to maintain homeostasis. Central nervous system changes have been studied both in their structural and functional component with advanced techniques, such as functional magnetic resonance (fMRI), showing the main involvement of the cerebellum, cortical sensorimotor, and somatosensory areas, as well as vestibular-related pathways. Analysis of electroencephalography (EEG) led to contrasting results, mainly due to the different factors affecting brain activity. The study of corticospinal excitability may enable a deeper understanding of countermeasures' effect, since greater excitability has been shown being correlated with better preservation of functions. Less is known about somatosensory evoked potentials and peripheral nerve function, yet they may be involved in a homeostatic mechanism fundamental to thermoregulation. Extending the knowledge of such alterations during simulated microgravity may be useful not only for space exploration, but for its application in clinical conditions and for life on Earth, as well.