Effect of histamine on spontaneous rhythmogenesis of the guinea pig ureter

Histamine changed characteristics of the perinephric spontaneous spike activity and of the spreading electrical wave. It was shown that histamine could activate latent pacemakers of the ureter's middle area. Morphological picture of the histamine effect was also shown.     

Bilaterally propagating waves of spontaneous activity arising from discrete pacemakers in the neonatal mouse cerebral cortex

Spontaneous electrical activity that moves in synchronized waves across large populations of neurons plays widespread and important roles in nervous system development. The propagation patterns of such waves can encode the spatial location of neurons to their downstream targets and strengthen synaptic connections in coherent spatial patterns. Such waves can arise as an emergent property of mutually excitatory neural networks, or can be driven by a discrete pacemaker. In the mouse cerebral cortex, spontaneous synchronized activity occurs for approximately 72 h of development centered on the day of birth. It is not known whether this activity is driven by a discrete pacemaker or occurs as an emergent network property. Here we show that this activity propagates as a wave that is initiated at either of two homologous pacemakers in the temporal region, and then propagates rapidly across both sides of the brain. When these regions of origin are surgically isolated, waves do not occur. Therefore, this cortical spontaneous activity is a bilateral wave that originates from a discrete subset of pacemaker neurons. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009     

Properties and mechanisms of spontaneous activity in the embryonic chick hindbrain

Spontaneous activity regulates many aspects of central nervous system development. We demonstrate that in the embryonic chick hindbrain, spontaneous activity is expressed between embryonic days (E) 6–9. Over this period the frequency of activity decreases significantly, although the events maintain a consistent rhythm on the timescale of minutes. At E6, the activity is pharmacologically dependent on serotonin, nACh, GABA_A, and glycine input, but not on muscarinic, glutamatergic, or GABA_B receptor activation. It also depends on gap junctions, t‐type calcium channels and TTX‐sensitive ion channels. In intact spinal cord‐hindbrain preparations, E6 spontaneous events originate in the spinal cord and propagate into lateral hindbrain tissue; midline activity follows the appearance of lateral activity. However, the spinal cord is not required for hindbrain activity. There are two invariant points of origin of activity along the midline, both within the caudal group of serotonin‐expressing cell bodies; one point is caudal to the nV exit point while the other is caudal to the nVII exit point. Additional caudal midline points of origin are seen in a minority of cases. Using immunohistochemistry, we show robust differentiation of the serotonergic raphe near the midline at E6, and extensive fiber tracts expressing GAD65/67 and the nAChR in lateral areas; this suggests that the medial activity is dependent on serotonergic neuron activation, while lateral activity requires other transmitters. Although there are differences between species, this activity is highly conserved between mouse and chick, suggesting that developmental event(s) within the hindbrain are dependent on expression of this spontaneous activity. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009     

A two way fully coupled fluid structure simulation of human ureter peristalsis

Abstract

Numerical simulations of ureter peristalsis have been carried out in the past to understand both the flow field and ureter wall mechanics. The main objective of the current investigations is to have a better understanding of the urine transport due to the peristalsis in the ureter, thus making the information helpful for a better treatment and diagnosis of ureteral complications like urine reflux. In the current study, a numerical simulation is performed using a finite-element-based solver with a two-way fully coupled fluid structure interaction approach between the ureter wall and urine. For the first time, the ureter wall is modeled as an anisotropic hyper-elastic material based on experiments performed in previous literature on the human ureter. Peristalsis in the ureter is modeled as a series of isolated boluses. By observing the flow field it is clear that the peristalsis mechanism has a natural tendency to create a backflow as the isolated bolus moves forward. As a result, the urine can flow back from the bladder to the ureter at the ureterovesical (ureter-bladder) junctions, if the one-way valve starts to malfunction.     

Bimodal septal and cortical triggering and complex propagation patterns of spontaneous waves of activity in the developing mouse cerebral cortex

Spontaneous waves of activity that propagate across large structures during specific developmental stages play central roles in CNS development. To understand the genesis and functions of these waves, it is critical to understand the spatial and temporal patterns of their propagation. We recently reported that spontaneous waves in the neonatal cerebral cortex originate from a ventrolateral pacemaker region. We have now analyzed a large number of spontaneous waves using calcium imaging over the entire area of coronal slices from E18‐P1 mouse brains. In all waves, the first cortical region active is this ventrolateral pacemaker. In half of the waves, however, the cortical pacemaker activity is itself triggered by preceding activity in the septal nuclei. Most waves are restricted to the septum and/or ventral cortex, with only some invading the dorsal cortex or the contralateral hemisphere. Waves fail to propagate at very stereotyped locations at the boundary between ventral and dorsal cortex and at the dorsal midline. Waves that cross these boundaries pause at these same locations. Waves at these stages are blocked by both picrotoxin and CNQX, indicating that both GABA_A and AMPA receptors are involved in spontaneous activity. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 679–692, 2010     

Spatio-temporal occurrence and sensitivity to livestock husbandry of Pallas's cat in the Mongolian Altai

Biased research and conservation efforts result in some faunal groups (e.g., small felids) being understudied, and hence these groups are often declining without adequate knowledge to manage for threat reduction. The Pallas's cat (Otocolobus manul) occurs across central and western Asia with declining populations and the largest population is likely in Mongolia. A potential threat to this felid is livestock encroachment across its range, including within protected areas, yet we lack a clear understanding of the impact of livestock husbandry on this cat. We used motion-sensitive camera data from 216 sites in 4 study areas in western Mongolia to study the occurrence probability of Pallas's cat in relation to habitat characteristics and occurrence of livestock, and conducted a local assessment within a strictly protected area where we obtained the highest number of detections. We estimated a relatively low occupancy (0.33 ± 0.10), which is associated with sites with natural vegetation, steeper slopes, and greater prey abundance. Occupancy also increased with increasing livestock occurrence, particularly large herds of sheep and goats. Such co-occurrence was partially adjusted by diel activity segregation, presumably to limit direct encounters. Our results suggest that the preferred habitat by Pallas's cat in the study region coincides with areas encroached by livestock. The Pallas's cat's habitat is specialized and its dependence on areas that are increasingly used for grazing may eventually threaten the cat with habitat degradation, prey depletion, predation by dogs, and poisoning from pest control. Relevant conservation actions should regulate livestock encroachment within protected areas and improve grazing regimes. The Pallas's cat is an indicator species of mountainous and steppe ecosystems in central Asia; hence, further research towards the preservation of its populations would also benefit other key species across its range.     

后腹腔镜输尿管切开取石15例体会

目的:探索腹膜后途径腹腔镜输尿管切开取石的方法。方法:采用后腹腔镜输尿管切开取石治疗输尿管中上结石患者15例。结果:13例成功,2例失败改为开放手术。手术平均时间约97分钟,术中出血约120ml,术后平均住院时间6、1天。结论:经腹膜后腹腔镜输尿管切开取石术是治疗输尿管中上结石的一种安全有效的手术方式,可取代部分开放手术,具推广价值。     

Analysis of spontaneous electrical activity in cerebellar Purkinje cells acutely isolated from postnatal rats

Whole-cell patch recording techniques were used to analyze spontaneous electrical activity in cerebellar Purkinje cells acutely isolated from postnatal rats. Spontaneous activity was present in 65% of the cells examined, and it included simple and complex firing patterns which persisted under conditions that eliminated residual or reformed synaptic contacts. Under voltage clamp, both spontaneous and quiescent cells displayed similar voltage-dependent conductances. Inward current was carried by Na⁺ through tetrodotoxin (TTX)-sensitive channels and by Ca²⁺ through P-type and T-type Ca channels. P-type current was present in all cells examined. T-type current was found in <50%, and it did not correlate with spontaneous activity. We found no evidence of a transient (A-type) potassium current or hyperpolarization-activated cationic current in either spontaneous or quiescent cells. Spontaneous activity did correlate with a lower activation threshold of the Na current, resulting in substantial overlap of the activation and inactivation curves. TTX reduced the holding current of spontaneous cells clamped between −50 and −30 mV, consistent with the presence of a Na "window" current. We were unable, however, to measure a persistent component of the Na current using voltage steps, a result which may reflect the complex gating properties of Na channels. An Na window current could provide the driving force underlying spontaneous activity, as well as plateau potentials, in Purkinje cells. © 1997 John Wiley & Sons, Inc. J Neurobiol 33: 18–32, 1997     

用脑光学成像精确测定猫初级视皮层视野拓扑投射关系

利用基于脑内源信号的光学成像和二维互相关分析的方法,对猫初级视皮层17区的视野拓扑离心度(即视网膜-皮层拓扑关系)进行了精确测量。当采用在同一屏幕内处于上下视野的、方位互相垂直的两个相邻光栅刺激时,皮层中一部分区域的绝大部分细胞因同时兴奋而导致方位功能图模糊不清。将这种方位功能图和用单一方位(水平或垂直)全屏光栅刺激所得到的功能图进行比较,通过计算每一像素的互相关系数,从而获得皮层的精确视野拓扑离心度。同时用电生理的方法测量了同一视皮层内的单细胞的感受野位置,证明这种方法得到的视野离心度和光学记录方法得到的相同。因此,本研究为大面积地确定视皮层细胞感受野在视野中的位置提供了一种快速和较准确的方法。     

The role of histamine in regulation of spontaneous electrical activity of the rat ureter and bordering to bladder area

The nature of the influence of histamine on the slow wave and spike spontaneous activity of both perirenal and peribladder bordering areas of the bladder zone has been studied. It is shown that under these conditions of activated renal section of the organ, in the distal part, the decrease in frequency of the slow waves occurred. The histamine effect also contributes to improvement of the conduction of the excitation wave propagating to the bladder, which destroys the coordination of spike activity of the latter with slow waves of ureteral bordering zone.     

The systematic status of the Iriomote cat (Prionailurus iriomotensis Imaizumi 1967) and the subspecies of the leopard cat (Prionailurus bengalensis Kerr 1792)

The taxonomic status of the Iriomote cat ( Prionailurus iriomotensis Imaizumi 1967) has been the subject of considerable discussion. Wozencraft's (1993) decision that it is merely a subspecies of Prionailurus bengalensis has been adopted by IUCN, which may affect the chances of conserving this unique animal. This paper reports on an investigation into the relationship between the Iriomote cat and other species, using skull measurements to calculate skull configurations, from which species and subspecies may be compared with each other. The results prove that the Iriomote cat cannot be subsumed as a subspecies of Prionailurus bengalensis but is a species of its own. It is closely related to the genus Prionailurus but also has affinities with the genera Pardofelis and Profelis . It appears to be a very ancient species, a 'missing link', nearer to the common root of the cat tribe than any other extant species.     

Genetics of cat hemoglobins: A quantitative polymorphism

Blood samples from domestic cats, representing the parents (26) and offspring (91) from 33 matings, were analyzed to determine the proportions of hemoglobins A and B. Evidence is presented that the proportions of the two hemoglobins are genetically determined and that cats may be divided into three groups on the basis of this characteristic. Family data and Hardy-Weinberg analysis support the hypothesis that the three groups represent the possible combinations of an allelic gene pair. In an attempt to explain the observed phenotypic differences, possible points of action of this gene pair are discussed, including effects on rates of synthesis or epigenetic modification of globin chains.     

Impact of predation by domestic cats Felis catus in an urban area

• 1 As companion animals, domestic cats Felis catus can attain very high densities, and have the potential to exert detrimental effects on prey species. Yet, there is a paucity of information on the impact of cat predation in urban areas, where most cats are likely to be present.
• 2 We quantified the minimum number of animals killed annually by cats in a 4.2-km² area of Bristol, UK, by asking owners to record prey animals returned home by their pets. The potential impact of cat predation on prey species was estimated by comparing the number of animals killed with published estimates of prey density and annual productivity.
• 3 Predator density was 229 cats/km².
• 4 Five mammal, 10 bird and one amphibian prey species were recorded. Mean predation rate was 21 prey/cat/annum. The most commonly recorded prey species was the wood mouse Apodemus sylvaticus.
• 5 Predation on birds was greatest in spring and summer, and probably reflected the killing of juvenile individuals. For three prey species (house sparrow Passer domesticus, dunnock Prunella modularis, robin Erithacus rubecula), estimated predation rates were high relative to annual productivity, such that predation by cats may have created a dispersal sink for juveniles from more productive neighbouring areas. The impact of cats on these species therefore warrants further investigation.

     

First isolation of Stephanoascus ciferrii from a cat

The present study deals with the first isolation of Stephanoascus ciferrii from a cat. A 2-year-old female Persian cat weighing 2.25 kg was referred to an animal hospital with a chief complaint of otitis externa of the left ear. Microscopic examination of specimen from the left ear disclosed yeast cells. The colony of the clinical isolate was cream-colored, rough, raised and wrinkled. The microscopic examination of the clinical isolate revealed abundant branched and septated mycelia with small ramified chains of oval blastoconidia, variable in size, and arranged alongside the hyphae. Amplification of the isolate DNA with LSU rDNA primers yielded a fragment of about 570 bp, whose nucleotide sequence of the isolate showed 100% similarity to that of Stephanoascus ciferrii in the GenBank database. Therefore, the isolate was identified as Stephanoascus ciferrii, confirming the result of mycological examination by molecular analysis.     

Response properties of cat AMLS neurons to optic flow stimuli

Spiral and translation stimuli were used to investigate the response properties of cat AMLS (anteromedial lateral suprasylvian area) neurons to optic flow. The overwhelming majority of cells could be significantly excited by the two modes of stimuli and most responsive cells displayed obvious direction selectivity. It is the first time to find a visual area in mammalian brain preferring rotation stimuli. Two representative hypotheses are discussed here on the neural mechanism of optic flow analysis in visual cortex, and some new viewpoints are proposed to explain the experimental results.     

猫小脑髓质胶质反应的年龄相关性变化

探讨青年猫和老年猫小脑髓质中胶质反应的年龄相关性变化及其意义。用改良的Holzer结晶紫染色显示所有胶质细胞,GFAP(胶质纤维酸性蛋白)免疫染色显示星形胶质细胞。光镜下对青年猫与老年猫小脑髓质中胶质细胞和GFAP免疫阳性(GFAP-IR)星形胶质细胞进行形态学观察和定量研究。与青年猫比较,老年猫小脑髓质中胶质细胞和GFAP-IR细胞密度均显著增加(P<0.01),胞体较大;GFAP阳性细胞阳性反应较强,突起稠密;星形胶质细胞占胶质细胞总数比例增加。这表明小脑髓质中胶质细胞随年龄增长明显增生,尤其星形胶质细胞具有明显的年龄相关性活动增强。提示胶质细胞及星形胶质细胞的增生可能对衰老的神经纤维起保护作用;星形胶质细胞对衰老较敏感。     

Response properties of cat AMLS neurons to optic flow stimuli

Spiral and translation stimuli were used to investigate the response properties of cat AMLS (anteromedial lateral suprasylvian area) neurons to optic flow. The overwhelming majority of cells could be significantly excited by the two modes of stimuli and most responsive cells displayed obvious direction selectivity. It is the first time to find a visual area in mammalian brain preferring rotation stimuli. Two representative hypotheses are discussed here on the neural mechanism of optic flow analysis in visual cortex, and some new viewpoints are proposed to explain the experimental results.     

Immunochemical assay of airborne cat allergen: value in assessing variability of allergen shedding and evaluating human bronchial response

Twelve cats were selected from the animal care facility to determine their individual rates of allergen shedding. Cats were placed in a lucite chamber with an air sampler attached. Radioallergosorbent (RAST) inhibition type and monoclonal two-site radioimmunosurveys (RIAs) were used to express air concentrations in allergy units (AU) orFel d 1 units), respectively. Inter-cat variability ranged from a factor of 6 (inFel d 1 units) to a factor of 100 (in AU). Production of individual cats over time varied by a factor of 10–20 (AU orFel d 1). Three of the highest shedders were placed in wire cages in a room-sized chamber with closed ventilation. Four cat-sensitive asthmatics were individually exposed to the cats in the chamber and had spiromatic and minute ventilation measurements performed while personal air sampling was performed. Allergen concentration in the chamber was higher than in homes we have measured. 11% (Fel d 1) or 17% (AU) of the allergen concentration was associated with respirable particles (<9 μm). The dose of allergen required to elicit a 20% drop in FEV₁ from baseline was calculated from the measured air concentration, patients' ventilation, particle sizing data and estimated lung deposition. This dose was substantially less than that required by breathing nebulized cat extract for 3 of the 4 subjects.