对碳青霉烯类抗生素敏感性下降的肠杆菌科细菌耐药机制的研究及流行病学调查

目的 对临床分离的碳青霉烯类抗生素耐药的肠杆菌科细菌进行耐药机制研究及流行病学调查.方法 收集2010年1月至2010年8月,对碳青霉烯类抗生素敏感性下降的肠杆菌科细菌18株,全自动微生物鉴定仪检测细菌对常见抗生素最低抑菌浓度(MIC),纸片法检测细菌产超广谱β-内酰胺酶、头孢菌素酶、碳青霉烯酶的情况,并用PCR扩增、DNA测序确定所产碳青霉烯酶基因型.脉冲场凝胶电泳对耐药菌进行同源性分析.结果 8株耐药菌全部检出ESBLs酶、AmpC酶,17株检出KPC-2酶,3株EDTA纸片法阳性提示产其他金属碳青霉烯酶,其中两株合并产KPC-2.脉冲场凝胶电泳结果显示15株肺炎克雷伯菌分为6种带型.结论 KPC-2碳青霉烯酶是造成肠杆菌科细菌对碳青霉烯类抗生素敏感性下降的主要原因,并在我院局部短暂流行,携带KPC-2基因的临床菌株同时携带多种耐药基因.     

质粒介导KPC-2型碳青霉烯酶肺炎克雷伯菌儿童分离株耐药基因研究

目的 研究碳青霉烯类耐药肺炎克雷伯菌临床儿童分离株的耐药特点及分子流行病学特征.方法 收集温州医学院附属第二医院2010年7月-2011年6月从儿童标本中分离的耐碳青霉烯类肺炎克雷伯菌12株,所有菌株为非重复菌株,菌种鉴定采用全自动微生物分析仪.改良的Hodge试验筛选产碳青霉烯酶阳性菌株,采用PCR法检测KPC、IMP、bla(s)、VIM、SPM和整合酶基因,测序确定基因型.对菌株进行质粒结合试验、质粒消除试验检测质粒的转移性.脉冲场凝胶电泳(PFGE)分析耐药菌株的同源性.结果 12株耐碳青霉烯类肺炎克雷伯菌对庆大霉素、妥布霉素、阿米卡星、环丙沙星、左氧氟沙星、复方磺胺甲噁唑的敏感率分别为8.3％、41.7％、58.3％、8.3％、8.3％、33.3％;12株菌均携带有KPC-2基因,且同时携带有TEM-1和SHV型β-内酰胺酶基因,其中SHV-11-like和SHV-1 2-like各6株;11株携带CTX-M型基因,其中4株为CTX-M-14-like基因,6株CTX-M-15-like基因;2株携带有OXA-10型基因,1株携带有PER-1基因.未检出NDM-1、GIM、SPM、SIM、VIM型碳青霉烯酶基因.12株均为Ⅰ类整合酶基因(int1)阳性.2株通过接合试验把质粒传递给受体菌EC600.所有接合子blaTEM-1基因阳性、超广谱β-内酰胺酶(ESBL)基因阳性及对亚胺培南、庆大霉素、阿米卡星、妥布霉素和头孢噻肟耐药,接合子ESBL基因型与供菌一致.2株菌经质粒消除后对亚胺培南的MIC值均有较大程度降低,消除后KPC-2基因扩增为阴性.12株KPC-2基因阳性菌株经PFGE分成5个基因型,主要为B型和C型.结论 KPC-2型碳青霉烯酶基因已经在儿童肺炎克雷伯菌中播散,常伴随携带多种类型的ESBL基因和Ⅰ类整合酶基因,部分耐药基因可通过质粒播散.     

重症医学科染KPC-2肺炎克雷伯菌的耐药情况分析及同源性研究

目的重症医学科染KPC-2肺炎克雷伯菌的耐药及同源性情况。方法从2018年4月至2019年2月于我院重症医学科室治疗的患者中提取40例耐碳青霉烯类肺炎克雷伯菌(CRKPN)菌株,对待测菌株进行药敏性试验、mCIM(改良碳青霉烯灭活试验)和eCIM(EDTA改良碳青霉烯灭活试验)联合试验,采用PCR扩增法检测待测菌的耐药基因并进行基因序列检测,采用PFGE对待测菌进行同源性分析。结果在16种抗菌药中,待测菌仅对阿米卡星(27.50%)、庆大霉素(17.50%)、妥布霉素(25.00%)、替加环素(100.00%)以及复方新诺明(55.00%)有敏感性;mCIM和eCIM试验结果显示40株CRKPN均产丝氨酸碳青霉烯酶;PCR试验结果显示待测菌株携带KPC基因阳性率为100%;选择ICU分离的17株CRKPN做PFGE,同源性结果分析显示该病区存在耐碳青霉烯肺炎克雷伯的克隆传播。结论我院重症医学科分离的CRKPN细菌的耐药机制是产丝氨酸碳青霉烯酶,酶基因为KPC-2型,PFGE结果分析显示我院重症医学科存在耐碳青霉烯肺炎克雷伯的克隆传播,需要加强院感监控工作。     

老年人亚胺培南耐药铜绿假单胞菌耐药性研究

目的 明确我院老年病人临床分离铜绿假单胞菌的耐药性、同源性及耐碳青霉烯菌株的基因型。方法 收集我院2006年5月-2009年5月自临床老年病人分离的262株铜绿假单胞菌,纸片扩散法测定其对16种抗菌药物的耐药性;琼脂稀释法和E test法测定耐碳青霉烯菌株对14种抗菌药物的MIC值,PCR扩增及克隆测序分析金属酶基因型。脉冲场凝胶电泳(PFGE)分析携带金属酶基因型菌株的同源性。结果 262株铜绿假单胞菌中筛选到104株耐碳青霉烯。104株耐碳青霉烯铜绿假单胞菌对氨苄西林/舒巴坦、头孢哌酮/舒巴坦两个含舒巴坦制剂药物耐药率分别为78.9％和35.9％,对多黏菌素E耐药率最低为6.0％,对米诺环素耐药率58.3％,其余抗菌药物耐药率均大于70.0％;104株亚胺培南耐药铜绿假单胞菌中12株携带金属酶基因,10株检测到有携带VIM-2基因的1类整合子。PFGE分型中12株菌株属于5个克隆株。结论 在我院流行的亚胺培南耐药铜绿假单胞菌中,金属酶基因不是最主要的基因型,金属β-内酰胺酶均为VIM-2型金属酶,耐药基因盒分布于不同的1类整合子中,整合子播散是最主要的流行方式。     

CMY型AmpC酶新基因亚型的序列分析与表达载体构建

目的 对两株弗劳地枸橼酸杆菌所产CMY型AmpC酶进行基因克隆、序列分析和重组表达载体的构建.方法 以产CMY型AmpC酶的弗劳地枸橼酸杆菌30、31号总基因组DNA为模板,PCR扩增CMY基因,将其克隆人pGEM-T载体后测定该核苷酸序列.30、31号菌与受体菌进行质粒接合实验,构建pBV220-CMY重组表达载体.对原菌株和重组菌株进行AmpC酶检测.结果 PCR扩增出大小为1146 bp的基因片段,与GenBank上多种CMY亚型的基因序列同源性为97%.质粒接合实验证实质粒上含CMY基因,为可转移质粒.三维实验结果显示30、31号菌和重组菌株所产的酶均能水解头孢西丁.结论 30、31号菌所产的CMY型AmpC酶为CMY新基因亚型.成功构建重组表达载体pBV220-CMY,为下一步酶的表达和纯化提供了依据.     

碳青霉烯耐药肺炎克雷伯菌产β-内酰胺酶及流行性研究

肺炎克雷伯菌(Klebsiella pneumoniae,Kpn)属条件致病菌,是临床分离及医院感染的重要革兰阴性杆菌之一.由于β-内酰胺类及氨基糖苷类等广谱抗菌素的广泛应用,肺炎克雷伯菌的多重耐药现象越来越严重,其主要机制之一是通过产生超广谱β-内酰胺酶(ESBLs)及头孢菌素酶(AmpC酶)实现;对于这些多重耐药菌,碳青霉烯类抗生素(如亚胺培南、美罗培南和厄他培南等)是目前可用的最有效药物.然而,近年来各种碳青霉烯水解酶的相继出现,临床中分离的碳青霉烯类抗生素耐药菌株的不断增加等现象使得碳青霉烯类耐药的肺炎克雷伯菌成为医学感染的严重威胁[1-2].     

大肠埃希菌对碳青霉烯类药物的耐药机制研究

目的 研究我院普外科重症监护病房(ICU)出现的对碳青霉烯类抗菌药物耐药的大肠埃希菌分子流行病学特征和碳青霉烯耐药机制.方法 采用琼脂稀释法检测分离株的抗菌药物敏感性,采用脉冲场琼脂糖凝胶电泳(PFGE)研究碳青霉烯类耐药的大肠埃希菌分子流行病学机制,采用特异性PCR、DNA测序分析、接合试验、质粒提取和质粒转化试验、外膜蛋白分析等技术研究碳青霉烯耐药的分子机制.结果 我院分离的14株碳青霉烯耐药菌分别属于10个流行克隆型,均表现对包括亚胺培南和美罗培南在内多种抗菌药物耐药,碳青霉烯类耐药基因扩增显示均携带KPC-2型碳青霉烯酶基因,质粒提取与转化试验显示KPC-2定位于约56 kb大小的质粒上,SDS-PAGE分析发现耐药株多出现外膜蛋白的改变.结论 我院出现多个流行克隆型的碳青霉烯类耐药的大肠埃希菌,质粒型碳青霉烯酶KPC-2是我院泛耐型大肠埃希菌介导对碳青霉烯类耐药的主要原因,外膜孔蛋白改变参与介导大肠埃希菌对碳青霉烯类高度耐药.     

产CTX-M型超广谱β-内酰胺酶大肠埃希菌的研究

目的 :了解四川大学华西医院产超广谱 β 内酰胺酶 (ESBLs)大肠埃希菌中CTX M基因的检出情况及产CTX M酶大肠埃希菌的耐药性和同源性。方法 :对 2 0 0 1年 1 0月～ 2 0 0 2年 5月我院临床分离的 30株产ESBLs大肠埃希菌采用琼脂平皿对倍稀释法和PCR方法进行耐药表型和 β 内酰胺酶基因型分析 ;对扩增的CTX M基因进行DNA序列分析 ;用脉冲场凝胶电泳 (PFGE)分型技术了解产CTX M酶大肠埃希菌同源性。结果 :1 3株菌携带CTX M基因 ,CTX M酶亚型为CTX M 3和CTX M 1 4。产CTX M酶菌株对第三代头孢菌素耐药率高 ,对头孢噻肟…     

儿童感染肺炎克雷伯菌产AmpC酶和ESBLs的检测及耐药性分析

目的了解广州地区儿童感染肺炎克雷伯菌产质粒介导的AmpC酶和超广谱β-内酰胺酶（ESBLs）的情况及其耐药特征,为临床合理用药提供参考依据。方法采用标准纸片扩散法检测ESBLs,头孢西丁三维试验法检测AmpC酶,K—B纸片法测定肺炎克雷伯菌对抗菌药物的敏感性。结果共检出248株肺炎克雷伯菌,其中46株产AmpC酶,阳性率为18．5％;157株产ESBLs,阳性率为63．3％;同时产AmpC酶和ESBLs菌株阳性率为18．1％。产AmpC酶肺炎克雷伯菌对第三代头孢菌素高度耐药。耐药率达80％～100％;对头孢吡肟、含酶抑制剂复合药的耐药率也在56．5％～93．5％之间：但对环丙沙星、阿米卡星的耐药率则在30％以下,对亚胺培南全部敏感。产ESBLs菌株对头孢菌素、含酶抑制剂复合药的耐药率也较高,在50％-91．7％之间,但对阿米卡星、环丙沙星、亚胺培南仍高度敏感。ESBLs阴性肺炎克雷伯菌对所测抗生素的敏感率均在81．2％以上。产酶菌株耐药率明显比非产酶菌株高。结论广州地区儿童感染肺炎克雷伯菌产ESBLs和AmpC酶的状况已十分突出：产酶菌株对常用抗生素的耐药率较高;碳青霉烯类抗生素可作为治疗产AmpC酶和／或ESBLs肺炎克雷伯菌感染的经验用药。     

产质粒介导AmpC酶和ESBLs细菌的耐药性及β-内酰胺酶基因型研究

目的　了解我院同时产质粒介导AmpC酶和超广谱 β 内酰胺酶 (ESBLs)肺炎克雷伯菌与大肠埃希菌的耐药性及其 β 内酰胺酶的基因型特征。方法　 110株临床分离无重复肺炎克雷伯菌与大肠埃希菌耐药株 ,采用酶提取物三维实验检测AmpC酶 ,美国临床实验室标准委员会 (NCCLS)表型筛选和确认实验检测ESBLs ;琼脂二倍稀释法测定抗生素对同时产AmpC酶和ESBLs菌株的最低抑菌浓度 (MICs) ;等电聚焦实验测定 β 内酰胺酶等电点 (pIs) ;质粒接合实验定位耐药基因 ;PCR通用引物扩增AmpC酶与ESBLs基因及其序列测定以确定其基因亚型。结果　同时产AmpC酶和ESBLs菌株在肺炎克雷伯菌与大肠埃希菌中的检出率分别为 7.7% (5 6 5 )、8.9% (4 4 5 )。该类产酶菌株产 2～ 3种pI5 .4～ 9.0 β 内酰胺酶 ,对第三代头孢菌素、氨曲南、头孢美唑和含酶抑制剂复合制剂的敏感性极低 ,但对亚胺培南均敏感。 9株质粒中均检出AmpC酶基因DHA 1亚型 ,其中 1株同时检出ACT 1亚型 ;ESBLs基因亚型分别为CTX M 14、CTX M 3、CTX M 9,各有 4、3、2株 ;有 3株还携带广谱酶TEM 1基因。结论　我院存在同时产质粒介导DHA 1、ACT 1型AmpC酶和CTX M型ESBLs肺炎克雷伯菌、大肠埃希菌流行株 ,药敏检测结果显示对大多数新型广谱 β 内酰胺类抗生     

Counterpointing the functional role of the forebrain and of the brainstem in the control of the sleep-waking system

This paper reviews the lifetime contributions of the author to the field of sleep-wakefulness (S-W), reinterprets results of the early studies, and suggests new conclusions and perspectives. Long-term cats with mesencephalic transection show behavioral/polygraphic rapid eye movement sleep (REMS), including the typical oculo-pupillary behavior, even when the section is performed in kittens prior to S-W maturation. REMS can be induced as a reflex. Typical non-rapid eye movement S (NREMS) is absent and full W/arousal is present only after a precollicular section. The isolated forebrain (IF) rostral to the transection exhibits all features of W/arousal and NREMS [with electroencephalographic (EEG) spindles and delta waves], arousal to olfactory stimuli, and including the appropriate oculo-pupillary behaviors. These features also mature normally after neonatal transection. REMS is absent from the IF. After deprivation there is NREMS pressure and rebound in the IF, but the decerebrate cat only shows pressure for REMS. Most IF reactions to pharmacologic agents are within expectations, except for the tolerance/withdrawal effects of long-term morphine use which are absent. In contrast, these effects are supported by the brainstem (i.e. seen in the decerebrate cat). In cats with ablation of the telencephalon, or diencephalic cats, delta waves are absent in the thalamus. EEG thalamic spindle waves are seen triggering S for only 4-5 days after ablation. Therefore, true NREMS is absent in chronic diencephalic cats although pre- and postsomniac behaviors persist. These animals are hyperactive and show a pronounced, permanent insomnia; however, a low dose of barbiturate triggers a dramatic REMS/atypical NREMS rebound. Cats without the thalamus (athalamic cats), initially show a dissociation between behavioral hyperactivity/insomnia and the neocortical EEG, which for 15-20 days exhibits only delta and slower oscillations. Fast, low-voltage W rhythms appear later on, first during REMS, but spindle waves and S postures are absent from the start, such that these cats also display only atypical NREMS. Athalamic cats also show barbiturate-sensitive insomnia. Cats with ablation of the frontal cortices or the caudate nuclei remain permanently hyperactive. They also show a mild, but significant hyposomnia, which is permanent in afrontal cats, but lasts for about a month in acaudates. The polygraphic/behavioral features of their S-W states remain normal. We conclude and propose that: (a) the control of the S-W system is highly complex and distributed, but is organized hierarchically in a well-defined rostro-caudal manner; the rostral-most or highest level (telencephalon), is the most functionally complex/adaptative and regulates the lower levels; the diencephalic/basal forebrain, or middle level, has a pivotal role in inducing switching between S and W and in coordinating the lowest (brainstem) and highest levels; (b) W can occur independently in both the forebrain and brainstem, but true NREMS- and REMS-generating mechanisms exist exclusively in the forebrain and brainstem, respectively; (c) forebrain and brainstem S-W processes can operate independently from each other and are preprogrammed at birth; this helps understanding normal and abnormal polygraphic/behavioral dissociations in humans and normal dissociations/splitting in aquatic mammals; (d) NREMS homeostasis is present in the IF, but only REMS pressure after deprivation persists in the decerebrate cat; (e) the thalamus engages in both NREMS and W; (f) insomnia in diencephalic cats is the result of an imbalance between antagonistic W- and S-promoting cellular groups in the ventral brain (normally modulated by the telencephalon); (g) the EEG waves, which are signature for each S-W state, appear to truly drive the concomitant behaviors, e.g. a hypothetical human IF could alternate between behavioral NREMS and W/arousal/awareness; (h) a role for REMS is to keep the individual sleeping at the end of the self-limiting NREMS periods. The need for accelerating research on telencephaling NREMS periods. The need for accelerating research on telencephalic S-W processes and downstream control of the lower S-W system levels is emphasized.     

Effects of the lesion of the postcommissural part of the septum on the behavior of the rat.

The effects of the lesion of the postcommissural part of the septum on behavior of the rat has been studied. Results may be summarized as follows. An increase in the exploratory behavior in the open field which decreases rapidly; a decrease in the number of defecations in this test and a decrease in time leaving a dark environment for exploration. In the shuttle box test, no facilitation of the acquisition, but a permanent and quite significant increase in the intertrial activity has been found. We conclude that the lesions tend to decrease the emotivity of the subjects. An interpretation on the basis of the species -- specific defensive reactions explains the transitory and permanent effects of the lesions on the spontaneous activity.     

The Beauty of the Network in the Brain and the Origin of the Mind in the Control of Behavior

Behavior is not adequately described as a stimulus-response process. It is initiated by the animal and is generated because of its expected outcome in the future. The outcome can be good or bad for the animal. The brain is in charge of the selection process. This is the basic function of the brain. Taking Drosophila as a study case, this paper discusses initiating activity, several examples of outcome expectations, trying out (the internal search for a suitable behavior), chaining of actions, and the functional roles of chance in action selection. It takes mental processes and states such as goals, intentions, feelings, memories, cognition, and attention as higher levels of behavioral control that have their origin in biological evolution.     

On the development of the sympathetic chain and the adrenal medulla in the mouse

Summary The first visible primordia of the sympathetic chain appear in the anterior thoracic region and run caudally through 8 segments in an embryo of 11 gestation days. At 12 gestation days the trunk reaches from the base of the skull into the sacral region. During the following days the trunk develops into ganglia with interganglionic fibers.At 16 gestation days there is a well developed trunk with a cranial ganglion cervicale superior and a ganglion stellatum in the anterior part of the thoracic region. In the remaining sympathetic chain there are segmentally arranged ganglia but in this common pattern large differences are noticed.At the 13th gestation day the first signs of the adrenal medulla and the splanchnic plexus appear in the form of sympathoblasts ventral to the sympathetic chain. The migration of sympathoblasts into the primordia of the adrenal cortex goes on for 3 days while the migration to the splancnic plexus in the mesenchym ventral and lateral to the aorta goes on at least 2 more days.     

Anatomical relationship between the morphology of the styloid process of the ulna and the attachment of the radioulnar ligaments

The radioulnar ligaments are the major stabilizers of the distal radioulnar joint under dynamic loading; however, anatomical detail regarding their attachment on the middle and distal thirds of the styloid process of the ulna remains unclear. Because previous anatomical studies included only old cadavers, their anatomical findings might not reflect the morphological features of younger and healthy specimens. This study investigated the anatomical features of the distal ulna, particularly the styloid process, to determine the attachment of the radioulnar ligaments to the styloid process and verified their direction and attachment to the styloid process in younger and healthy donors using magnetic resonance imaging (MRI). We investigated the morphological features of the distal ulna of 12 cadaveric wrists using micro-computed tomography (micro-CT). We also visualized and measured the distribution of the cortical bone thickness. We histologically analyzed three specimens in the axial plane and macroscopically analyzed seven specimens to examine the attachment of the radioulnar ligaments to the styloid process. In addition, we evaluated five wrists from living volunteers using 3.0 Tesla MRI. The distal ulna has a ridge on the dorsoradial aspect of the styloid process that corresponds to the attachment of the radioulnar ligaments. Micro-CT images after data processing revealed that the cortical thickness of the dorsoradial quadrant was thicker than that of the other quadrant at the proximal slice of the styloid process (p < 0.01), and that of the dorsoulnar (p = 0.021) and ulnopalmar (p < 0.01) quadrants at the middle slice. Histological analyses showed that the radioulnar ligaments were attached to the middle and distal thirds of the styloid process via chondral-apophyseal entheses. The direction of the fiber was dorsal in the middle third of the styloid process and changed to palmar in the distal third of the styloid process. The direction and attachment of the radioulnar ligaments on the styloid process were confirmed using MRI for younger and healthy participants. The radioulnar ligaments were attached to the dorsoradial ridge of the styloid process, which was confirmed by cortical bone thickening, histology at the attachment sites, and in vivo MR imaging. The directions of the radioulnar ligaments sterically intersected, which would satisfy both slipping stability and rotational mobility. These anatomical findings may provide the basis for biomechanical consideration of distal radioulnar joint stabilization.     

Adequate function of the cell: Interactions between the needs of the cell and the needs of the organism

The continuous maintenance of cell adequate function (cellular stress) is considered to be the main feature which characterizes the activity of a live cell. In accordance with the concept of cellular stress, the transition of the cell to the state of adequate funcitoning represents a dual commitment. The cell must function adequately to respond to the demands of the organism and to provide for its own needs. Thus, it is proposed that two systems exist for the regulation of the adequate function of the cell: one enabling the cell to respond to the demands of the organism, and the other providing for the needs of the cell itself. The hormonal system of the organism represents the first of these mechanisms, and I believe that another system exists for regulation of intracellular needs. Adequate function of the cell is determined by the regulative, controlling and defense mechanisms. The balance between the needs of the cell and of the organism should be a concern of physician, since it provides for the optimal function and health of the organism as a whole.     

指背腱膜滑动与近侧指间关节屈曲关系及临床意义

目的:探讨指背腱膜滑动距离与近侧指间关节(PIP)屈曲关系,为临床修复提供解剖学基础。方法:男性成人新鲜尸体标本10侧30指(示、中、环指各10指),切除手指皮肤,不破坏腱鞘、屈肌支持带、伸肌支持带、内在肌及外在肌,使肌腱保持正常的生理状态,分别测量各指中央束(CS)、侧束(LB)在PIP屈曲45°和90°时的滑动距离。结果:当PIP屈曲45°时,CS滑动距离为(2.7±0.4)mm,LB滑动距离为(2.8±0.6)mm;当PIP屈曲90°时,CS滑动距离为(4.3±0.7)mm,LB滑动距离为(4.8±0.6)mm。结论:指背腱膜滑动距离减少,严重影响手指的屈曲功能。对于指背腱膜的新鲜性损伤应予以精确修复;对于陈旧性损伤的修复应确保指背腱膜的正常滑动范围。     

On the musculature of the gastro-intestinal tract of the guinea-pig

Summary The small intestine, caecum, colon and part of the stomach of guinea-pigs were studied by light microscopy, using semithin sections of plastic embedded specimens. The muscular coat is thicker in the duodenum than in the rest of the small intestine. The ratio between longitudinal and circular muscle is 1:4.6 in the duodenum and it increases regularly along the small intestine, to reach 1:2 in the terminal ileum. In the caecum, shape and sectional area of the muscle tissue were analyzed along the full length of the taeniae. In the caecal circular muscle there is a characteristic change in the arrangement of the muscle bundles from the regions in the centre of the haustrations to the regions of the grooves between haustrations or to those lying beneath a taenia. The functional significance of the taeniae is discussed in terms of an arrangement allowing reduction of the lumen of the organ (which at the level of the grooves between haustrations acquires a triangular outline) more efficiently than if the longitudinal musculature were spread over the entire surface of the organ. Haustrations are present also on one side of the wall of the ascending colon where there is no longitudinal muscle layer. In the descending colon the structure of the wall is examined in different functional states, namely in the regions between fecal pellets (constricted regions) and in the regions around a fecal pellet (moderately distended regions). The musculature increases considerably in thickness in the constricted regions (both muscle layers being actively contracted), while the mucosa and submucosa are thrown into prominent longitudinal folds. These folds produce occlusion of the lumen when the circular muscle has shortened by about 50%.     

On the origin of the corticotectal projections in the cat

Summary Stereotaxic injection of horseradish peroxidase into the superior colliculus produced retrograde labelling of layer V pyramides in the Clare Bishop area and the lateral bank of the suprasylvian sulcus, in area 17,18 and 19. Single labelled cells were also found scattered in the splenial, the suprasplenial, the lateral and the suprasylvian gyri. In the cruciate sulcus no labelled cells were observed. Autoradiographically, the lateral bank of the suprasylvian sulcus was also shown to give rise to fibres to the superior colliculus.