流域空间结构指标与药物污染水平的关系研究

流域地表特征与土地利用结构同流域水环境质量关系密切。流域空间结构指标能够表征流域空间结构特征和生态功能,主要包括流域特征指标和景观格局指数等。为探讨海湾流域生态系统结构与药物污染特征之间的关系,以浙江象山湾为研究区域,采用固相萃取、超高效液相色谱质谱联用等分析手段,研究流域水环境中药物的污染水平、分析其分布特征与流域特征指标和景观结构的关系。结果表明,象山湾22个流域共有22种药物检出,总检出浓度范围为n.d.—220.2 ng/L,主要包括林可霉素、大环内酯类、喹诺酮类、抗癫痫药物、β受体阻滞剂、抗抑郁药物,其中林可霉素、大环内酯类和抗癫痫药物的检出率高达100%,检出浓度分别为2.36—29.1 ng/L、n.d.—35.8 ng/L和n.d.—37.5 ng/L。流域地貌结构指标与水环境药物污染关系密切,其中平均坡度(MS)与药物总浓度、面积高程曲线斜率(SAEC)与β受体阻滞剂都呈显著负相关关系(P<0.01);流域景观结构也与水环境药物污染紧密相关,其中景观蔓延度指数(CONTAG)、城镇用地面积加权平均形状因子(IsSHAPE-AM)、林地最大斑块景观面积比(fLPI...     

The future burden of cancer in Canada: Long-term cancer incidence projections 2013–2042

BackgroundCancer is the leading cause of death in Canada and the estimated annual spending associated with cancer is approximately $7.5 billion. Projecting the future burden of cancer in Canada is essential for health planning and evaluation. We aimed to estimate the future incidence of cancer in Canada to 2042.MethodsAge-sex-region-specific cancer incidence data were obtained for the years 1983-2012 and cancer incidence was projected from 2013 to 2042 for the top five cancer sites. The modelling algorithm combined a mixture of cancer projection methods to select the best-fitted model. When the chosen model produced by the modelling algorithm resulted in estimates that were not consistent with expert opinion, an alternate model was selected that took into consideration historical changes in policy, screening and lifestyle behaviours. Incidence projections were made for Canada and its provinces.ResultsLung cancer incidence is estimated to rise to 14,866 cases in men and 19,162 in women in 2042. Colorectal cancer incidence is estimated to rise to 28,146 in men and 21,102 in women. Cases of bladder cancer are projected to rise to 10,708 and 3,364 in men and women, respectively. Breast cancer incidence is predicted to rise to 40,712 and prostate cancer incidence is projected to rise to 92,949.ConclusionThese cancer incidence projections up to 2042 can be used for planning cancer control strategies and prevention programs. Given the ongoing changes in the prevalence of risk factors and in cancer prevention policies, these estimates should be interpreted with caution.     

Position,guidance, and mapping in the developing visual system

Positional identity in the visual system affects the topographic projection of the retina onto its central targets. In this review we discuss gradients and positional information in the retina, when and how they arise, and their functional significance in development. When the axons of retinal ganglion cells leave the eye, they navigate through territory in the central nervous system that is rich in positional information. We review studies that explore the navigational cues that the growth cones of retinal axons use to orient towards their target and organize themselves as they make this journey. Finally, these axons arrive at their central targets and make a precise topographic map of visual space that is crucial for adaptive visual behavior. In the last section of this review, we examine the topographic cues in the tectum, what they are, when, and how they arise, and how retinal axons respond to them. We also touch on the role of neural activity in the refinement of this topography. © 1993 John Wiley & Sons, Inc.     

Central projections of sensory cells of the midleg of the locust,Schistocerca gregaria

The central projections of trichoid hairs and of some scolopidial organs of the mesothoracic leg of the locust Schistocerca gregaria were studied by using nickel chloride backfilling and single cell recording. Trichoid hair sensilla on different parts of the legs project somatotopically in the ventral part of the ipsilateral neuropile of the mesothoracic ganglion. Generally, distally located receptors have their terminal arborizations in ventro-lateral areas of the neuropile, and proximally located receptors in ventro-medial areas. The axons of the subgenual organ and tarsal chordotonal organs project into the intermediate neuropile.     

Regressive post-hatching development of acetylcholinesterase-positive neurons in the pineal organs of Coturnix coturnix japonica and Gallus gallus

Summary Distribution and number of acetylcholinesterase-positive neurons were studied in the Japanese quail and the domestic fowl during the post-hatching period by means of the acetylcholinesterase method. For comparison, the development of the catecholamine-containing (sympathetic) pinealopetal fibers of the domestic fowl was demonstrated with the use of the glyoxylic acid method. The number of acetylcholinesterase-positive ganglion cells in the pineal organs of both avian species decreased rapidly after hatching, with a concentration of these elements in the basal portion (stalk) of the pineal organ.In 3-day-old chickens, perivascular catecholamine-containing nerve fibers penetrate the antero-lateral walls of the pineal organ and are found exclusively in the interfollicular and perivascular tissues. In 13-day-old and adult fowl, these fibers increase in number and terminate not only in the interfollicular space but also in the neuroepithelial parenchyma of the pineal body.The ontogenetic regression of the sensory structures paralleled by an expanding sympathetic innervation in the pineal organ of a galliform species resembles somewhat the process of phylogenetic transformation leading from pineal sense organs to pineal glands.This work was supported by a grant (No. 56480080) from the Ministry of Education, Science and Culture of Japan.Fellow of the Alexander von Humboldt Foundation (1982).     

Distribution and specific central projections of mechanoreceptors in the thorax and proximal leg joints of locusts

Summary Tactile hairs on the locust thorax can be divided into two classes by their external morphology and their central projection pattern: Short hairs, 10–100 m in length, which are assembled in distinct plates and rows, and long hairs, 100–800 m in length, which are distributed all over the body and are organized in large fields or aligned along the ridges of the appendages.The sensory fibers of the first class arborize in the lateral dorsal neuropile of thoracic ganglia and then extend further into the ipsilateral half of the corresponding ganglion in three main bundles from which fine rami of fibers end in the intermediate neuropile. In all three thoracic ganglia the projection pattern of homologous hair plates is similar.The sensory fibers of the second class exclusively terminate in special median ventral neuropiles, the ventral association center (VAC) and ventralmost ventral association center (VVAC). In addition fibers from meso- and metathoracic hairs, located close to the longitudinal midline of the animal, may terminate in the contralateral VAC and with one branch project to the next anterior ganglion through the ipsilateral connective. In contrast, fibers from prothoracic hairs were not found to leave their ganglion.With support by the DFG Neurale Mechanismen des VerhaltensSome of the studies were started at Universität Bielefeld, Fakultät für Biologie II (Abtlg. Prof. Dr. P. Görner)     

Nuclear envelope projections from pronuclei in karyogamy ofSpirogyra

Karyogamy ofSpirogyra (S. verruculosa andSpirogyra sp.) was investigated by electron microscopy. After conjugation both male and female pronuclei migrated to the center of the zygote and adjoined. Many regular finger-like projections arose from the nuclear envelopes of the pronuclei; each involved both the outer and inner nuclear membranes and was ca. 0.17 μm in diameter. The inner membrane was underlaid by electron-dense bands parallel to one another in arrangement and perpendicular to the axis of protrusion in direction. Subsequently, the two pronuclei were connected by internuclear bridges, and the approximating surfaces of them were closely apposed. The bridges resembled the said projections both in diameter and structure, having a diameter of ca. 0.17 μm and electron-opaque bands lining the inner membrane. The adjacent surfaces of the two pronuclei approximated to each other more and more, and by 30 days after conjugation both pronuclei intermingled into a synkaryon, from which the projections disappeared. Probably, the nuclear envelope projections are involved in the initial contact between the two pronuclei and then the internuclear bridges are formed.     

The effect of cytochalasin B,colchicine and vinblastine on the adhesion of Trichomonas vaginalis to glass surfaces

The attachment of Trichomonas vaginalis to glass surfaces was studied in the presence of cytochalasin B, colchicine and vinblastine. Marked inhibition of adhesion was noted with high concentrations of cytochalasin B. Colchicine and vinblastine were without effect. These findings suggest that Trichomonas vaginalis adhesion is at least partially mediated by the extension of cellular probes, due to the action of cytochalasin-sensitive microfilaments.     

Modification of callosal afferents of the primary visual cortex ipsilateral to the remaining eye in rats monocularly enucleated at different stages of ontogeny

Summary Callosal afferents to the primary visual cortex (area Oc1) mainly originate in the border region between the lateral portion of the primary visual cortex (area Oc1) and the laterally positioned secondary visual cortex (area Oc2L) of the contralateral hemisphere. The extent of this region has been determined by retrograde labeling with horseradish peroxidase (HRP). In normal rats the width of the retrogradely labeled cortical strip is about 0.3 mm. In rats monocularly enucleated from the 23rd up to the 44th ontogenetic day and subsequently injected as adults with HRP into Oc1 ipsilateral to the remaining eye, the perikarya of the callosal afferents from the opposite hemisphere are labeled in the form of significantly wider columns (about 0.8 mm) than in animals enucleated from the 50th ontogenetic day onwards. The latter do not differ from controls.