一氧化氮与卵巢生理

NO是一种结构简单的气体,是脊椎动物体内已发现的分子量最小的生物活性分子。NO作为一种信使分子,生物作用广泛,在生殖系统发挥重要作用。本文着重介绍NO作为卵巢内重要的调节因子,在调节卵泡发育、卵母细胞成熟、排卵、黄体的形成与退化、激素合成等方面的研究进展。     

Visualization of maturation of the corpus callosum during childhood and adolescence using T2 relaxometry

Previous studies have shown that maturation of the white matter in terms of its relative signal intensity changes on MRI is almost complete at 2-3 years of age. We hypothesized that quantitative analysis may show maturation of the white matter during childhood and adolescence. In the present study we performed multi-echo T2 relaxometry in 33 healthy subjects (girls, 15; boys, 18) aged 3-15 years. T2 relaxation times of the genu and splenium were measured. In healthy subjects, the T2 relaxation times were significantly correlated with age in both girls (r=0.611, p=.016) and boys (r=0.721, p=.001) in the splenium, but not in the genu (p>.05). To further confirm genu-to-splenium signal intensity ratio changes, a total of 389 brain MRIs were retrospectively selected from the patients who had normal results (189 girls/women, 200 boys/men; age range, 3-20 years). The genu-to-splenium signal intensity ratio was obtained from the T2-weighted images. In patients with normal MRI, the genu-to-splenium signal intensity ratio was significantly decreased with age (p<.001) by 16 years. The T2 relaxation times gradually increase in the splenium during childhood and adolescence, suggestive of maturation.     

家兔输卵管结扎术后黄体的形态变化

将27只雌性家兔随机分为五组,即Pomeroy法扎管组;Uchida法扎管组;结扎子宫动脉组;结扎卵巢动脉组和假手术组。术后4～10周合笼交配。交配后第八天取黄体做光镜和透射电镜观察。结果:Uchida法扎管后黄体的形态正常;Pomeroy法扎管和结扎子宫动脉后黄体的形态有轻微改变;结扎卵巢动脉后黄体的形态有明显改变。研究结果对探讨“扎管后综合征”的发生机制具有一定的意义。     

Veränderungen von Spontanaktivität und Reizantwort retinaler und geniculärer Neurone der Katze bei fraktionierter Injektion von Pentobarbital-Na (Nembutal)

Zusammenfassung 1. Die Veränderungen der spontanen und Reaktionsaktivität von Neuronen des Tractus opticus und der Radiatio optica wurden bei fraktionierter Injektion von Pentobarbital-Na (Nembutal) untersucht. Dabei wurden in 5 min-Abständen jeweils 5 mg Nembutal injiziert und die mittlere Entladungsrate, das Intervall- und Poststimulushistogramm aufgenommen.2. Die Spontanaktivität der meisten retinalen Neurone zeigte bei Nembutaldosen zwischen 5 und 30 mg eine Zunahme der mittleren Entladungsrate, bei Experimenten mit geringer Spontantätigkeit bereits in der Kontrolle wurde von Anfang an eine Aktivitätsminderung beobachtet. Über 30 mg fällt die mittlere Entladungsrate bei allen Neuronen ab. Nach jeder Einzelinjektion kommt es zu einem mehrphasischen Verlauf der Entladungstätigkeit mit initialer Zunahme, sekundärer überschießender Verminderung und langsamer Erholung in einen steady state. Bei post-geniculären Neuronen fehlt die initiale Aktivitätssteigerung.3. Retinale Ganglienzellen zeigen bei niedrigen und mittleren Barbituratdosen charakteristische Veränderungen des Entladungsmusters mit gruppierten Entladungen und multimodalen Intervallverteilungen. Dabei sind die kürzesten Intervalle bei allen Neuronen mit 4–5 msec außerordentlich konstant und dosisunabhängig. Die längeren Intervalle (15–35 msec und Vielfache) sind variabler und dosisabhängig. Die beobachteten Vorzugsintervalle werden durch die supra- und subnormale Phase der Neurone nach dem Aktionspotential erklärt (delayed depolarization und polarizing afterpotential).4. Die Reaktion auf Lichtpunktreize im rezeptiven Feldzentrum zeigt eine stärkere Verminderung der späten tonischen als der initialen phasischen Reizantwort. Bei on-Zentrum-Neuronen tritt mit abnehmender steady-state-Aktivität eine off-Erregung in Erscheinung, die vor der Narkose zwar bereits vorhanden, aber nicht erkennbar war. Off-Zentrum-Neurone zeigen nur eine leichte Verminderung der off-Aktivierung. Die Reaktionen geniculärer Neurone wurden stärker vermindert als die von retinalen Neuronen.5. Die Bedeutung peripherer und allgemeiner neuronaler Faktoren für die Interpretation von Narkoseeffekten wird hervorgehoben.Die Arbeit wurde mit Unterstützung der Deutschen Forschungsgemeinschaft durchgeführt (Cr 30).     

The effect of varying impact energy on diffuse axonal injury in the rat brain: a preliminary study

Diffuse axonal injury (DAI) is seen as widespread damage in the white matter of brain characterized by morphological changes to axons throughout the brain and brain stem. The current study attempted to investigate the effect of increasing impact energy on the presence and severity of DAI in corpus callosum (CC). DAI was induced in adult male Sprague-Dawley rats using an injury model adapted from Marmarou et al. in 1994. A 450-g cylindrical brass weight was dropped from three different heights (2.0 m, 1.5 m and 1.0 m) on to a metal helmet affixed to the skull of the rats. In the sham group, rats underwent a surgical procedure with no impact. After a 24-h survival period the animals were transcardially perfused. The brain was removed and the cerebral hemispheres were sectioned with a vibrotome and stained by silver impregnation technique. The CC of all the impacted rats showed DAI in the form of beaded axons, retraction balls and vacuole-like enlargements. The axonal injury was most severe in the 2-m group, while mildest in the 1-m group. In the sham group, axons appeared to be normal. This study demonstrates evidence of graded DAI depending on the impact energy. Such data is useful for mathematical modeling of axonal injury in rat brain using the same impact parameters and potential determination of injury thresholds for neural trauma. Electronic Publication     

Primrose syndrome associated with unclassified immunodeficiency and a novel ZBTB20 mutation

Primrose syndrome is a congenital malformation syndrome characterized by intellectual disability, developmental delay, progressive muscle wasting, and ear lobe calcification. Mutations in the ZBTB20 gene have been established as being accountable for this syndrome. In this study, a novel de novo ZBTB20 mutation, NM_001164342.2:c.1945C>T (p.Leu649Phe), has been identified through whole exome sequencing (WES) in a female patient presenting a typical Primrose phenotype. Because the present patient exhibited recurrent otitis media, detailed immunological examinations were performed in this study and subnormal immunoglobulin levels were firstly identified in a Primrose patient. Anatomical anomaly of the inner ear has never been reported in this patient and WES data did not include any relevant variants causally linked with the immunologic defect. Thus, there is a possibility of a relation between an unclassified immunodeficiency with selective IgG2 deficiency and Primrose syndrome and this may be the reason of recurrent otitis media frequently observed in Primrose patients. Because subnormal levels of IgG2 in this patient might be caused by an unrelated and still uncharacterized genetic cause, further studies are required to prove the causal link between aberrant ZBTB20 function and immunodeficiency.     

Phenotype delineation of ZNF462 related syndrome

Zinc finger protein 462 (ZNF462) is a relatively newly discovered vertebrate specific protein with known critical roles in embryonic development in animal models. Two case reports and a case series study have described the phenotype of 10 individuals with ZNF462 loss of function variants. Herein, we present 14 new individuals with loss of function variants to the previous studies to delineate the syndrome of loss of function in ZNF462. Collectively, these 24 individuals present with recurring phenotypes that define a multiple congenital anomaly syndrome. Most have some form of developmental delay (79%) and a minority has autism spectrum disorder (33%). Characteristic facial features include ptosis (83%), down slanting palpebral fissures (58%), exaggerated Cupid's bow/wide philtrum (54%), and arched eyebrows (50%). Metopic ridging or craniosynostosis was found in a third of study participants and feeding problems in half. Other phenotype characteristics include dysgenesis of the corpus callosum in 25% of individuals, hypotonia in half, and structural heart defects in 21%. Using facial analysis technology, a computer algorithm applying deep learning was able to accurately differentiate individuals with ZNF462 loss of function variants from individuals with Noonan syndrome and healthy controls. In summary, we describe a multiple congenital anomaly syndrome associated with haploinsufficiency of ZNF462 that has distinct clinical characteristics and facial features.     

Morphology of visual callosal neurons with different locations,contralateral targets or patterns of development

In kittens, callosally projecting neurons were labeled by retrograde transport of FITC- (fluorescein isothiocyanate)- and TRITC- (tetramethylrhodamine isothiocyanate)-conjugated latex microspheres injected in two different visual areas (17, 17/18, 19, or postero-medial lateral suprasylvian; PMLS) at postnatal day 3. At postnatal day 57 more than 1200 labeled neurons in visual cortical areas were intracellularly injected with 3% lucifer yellow (LY) in perfusion-fixed slices of the contralateral hemisphere. The distribution of labeled neurons was charted, and LY-filled neurons were classified on the basis of their area and layer of location, and dendritic pattern. The dendritic arbors of 120 neurons were computer reconstructed. For the basal dendrites of supragranular pyramidal neurons a statistical analysis of number of nodes, internodal and terminal segment lengths, and total dendritic length was run relative to the area of location and axonal projection. Connections were stronger between homotopic than between heterotopic areas. Overall tangential and laminar distributions depended on the area injected. Qualitative morphological differences were found among callosally projecting neurons, related to the area of location, not to that of projection. In all projections from areas 17 and 18, pyramidal and spinous stellate neurons were found in supragranular layers. In contrast, spinous stellate neurons lacked in projections from area 19, 21a, PMLS and postero-lateral lateral suprasylvian (PLLS). In all areas, the infragranular neurons showed heterogeneous typology, but in PMLS no fusiform cells were found. Quantitative analysis of basal dendrites did not reveal significant differences in total dendritic length, terminal, or intermediate segment length among neurons in area 17 or 18, and this was related to whether they projected to contralateral areas 17–18 or PMLS. All injections produced exuberant labeling in area 17. No differences could be found between neurons in area 17 (with transient axons through the corpus callosum) and neurons near the 17/18 border (which maintain projections to the corpus callosum). In conclusion, morphology of callosally projecting neurons seems to relate more to intrinsic specificities in the cellular composition of each area than to the area of contralateral axonal projection or the fate of callosal axons.     

The distribution of posterior parietal fibers in the corpus callosum of the rhesus monkey

Summary The distribution of posterior parietal fibers in the corpus callosum of the rhesus monkey was analyzed using autoradiographic techniques. Posterior parietal fibers are located in the posterior half of the body of the corpus callosum. There is some segregation of fibers with respect to their place of origin within the posterior parietal lobe. However, there is also overlap, particularly between fibers coming from the caudal inferior parietal lobule and the medial parietal lobe.Supported by the Veterans Administration, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Massachusetts and N.I.H. Grants NS 09211 and NS 16841     

Transcallosally evoked responses in the visual cortex of normal and monocularly enucleated rabbits

Summary In visual cortex of normal adult rabbits, callosal projections are restricted to a 2 mm wide band at the area 17/18 border. In adult rabbits which are monocularly enucleated (ME) on the day of birth, the callosal zone extends 4 mm into the medial region of area 17 in the cortex ipsilateral to the remaining eye. In this study, the function of these anomalous callosal projections in ME rabbits was investigated using electrophysiological techniques. A microelectrode was placed in the visual cortex ipsilateral to the enucleated eye at the 17/18 border, bipolar stimulating electrodes were placed in a homotopic location in the contralateral cortex, and averaged evoked responses (AERs) to stimulation were recorded. The stimulating electrodes were then moved mediolaterally in 1 mm steps, and the AERs were recorded for each location of the stimulating electrodes. In the normal rabbit, a maximal short latency evoked response was recorded when the stimulating electrodes were at a location homotopic to the recording electrode. When the stimulating electrodes were moved a distance of 1 mm or more from this optimal position, this short latency response was either absent or dramatically decreased in amplitude, reflecting the precise topographic pattern of the normal callosal projection. In contrast, in ME rabbits, a consistent response was evoked at the 17/18 border when the stimulating electrodes were moved as much as 3 mm medial to the homotopic position. Since antidromically activated responses and both pre- and post-synaptic orthodromically activated responses contribute to the AER, recordings were also made from single cells in some animals. Orthodromically activated single cell responses were evoked by electrical stimulation in the abnormal medial callosal zone of ME rabbits. The data indicate that abnormal callosal projections in ME rabbits can mediate functional interactions between nonhomotopic areas of the primary visual cortices.