The prognostic value of maximal exercise testing soon after first myocardial infarction

The prognostic value of ST-segment depression during maximalexercise test performed in the third to fourth week after acutemyocardial infarction (AMI), was studied in 126 consecutivepatients with no evidence of previous myocardial infarction,unstable angina pectoris or severe heart failure. All patientson average increased their pressure-rate product by 2.6 andno complications occurred. Within the first year of follow-up,major cardiac events occurred in 9 patients (20%), and werefatal in 6 (13%), of the 46 patients who developed ST-segmentdepression during exercise. Only 3 major cardiac events (4%)occurred in the 80 patients without exercise induced ST-segmentdepression. Depression of the ST-segment on maximal exercisewas a significant predictor of subsequent cardiac events inthese survivors of first AMI.     

Cerebellar efferents in the lizard Varanus exanthematicus. II. Projections of the cerebellar nuclei

The projections of the cerebellar nuclei have been studied in the lizard Varanus exanthematicus with various experimental anatomical techniques. In anterograde degeneration experiments (lesions of the cerebellar peduncle) both ascending and decending contralateral projections were found. Ascending fibers which could be traced from the cerebellar commissure ventralward decussated at the level of the trochlear and oculomotor nuclei. These fibers coursed rostralward to the mesodiencephalic junction. With anterograde tracing techniques (3H-leucine and HRP) this tract was found to terminate in the nucleus ruber and the interstitial nucleus of the fasciculus longitudinalis medialis. Moreover, retrograde tracer studies (HRP, "Fast Blue") showed that this tract appeared to arise mainly in the lateral cerebellar nucleus. With both anterograde degeneration and tracing techniques (3H-leucine and HRP) a bundle of fibers could be followed, which decussates in the basal part of the cerebellum and passes dorsally around the contralateral medial cerebellar nucleus to the lateral side of the brainstem. This contralaterally descending projection system was found, lateral to the vestibular nuclear complex, and as far caudally as the descending vestibular nucleus, to terminate on various vestibular nuclei. Horseradish peroxidase studies showed that this contralaterally descending projection system originates mainly in the medial cerebellar nucleus, but ipsilaterally descending projections were also found. With the fluorescent double labeling technique ("Fast Blue" and "Nuclear Yellow") the projections of the cerebellar nuclei described above were confirmed. Furthermore, double labeling revealed neurons in both cerebellar nuclei (especially the medial nucleus) that project to both the mesencephalon and the cervical spinal cord. The present results indicate that the efferent connections of the cerebellar nuclei in the lizard Varanus exanthematicus are organized as two main projections, an ascending projection comparable to the mammalian brachium conjunctivum arising in the lateral cerebellar nucleus, and a descending projection comparable to the mammalian hook bundle (fasciculus uncinatus), originating mainly in the medial cerebellar nucleus. Such projections are common for terrestrial vertebrates.     

腹腔镜解剖性肝Ⅶ段切除术的难点与应对策略

腹腔镜解剖性肝Ⅶ段切除术是被公认难度较大的肝段切除手术方式之一。肝Ⅶ段因其位置与解剖特点,行解剖性肝切除术时存在显露不佳、操作困难、肝蒂解剖复杂、切除平面难以确定和断肝容易出血等问题。笔者在行腹腔镜解剖性肝Ⅶ段切除术时病人常规采取左侧半卧位,将Trocar布局整体向右季肋区偏移,根据术前三维重建个体化选择适宜的肝Ⅶ段肝蒂解剖方式,由肝Ⅵ和Ⅶ段间平面开始离断肝脏,以垂直方向寻找和显露肝右静脉主干,然后以肝右静脉作为肝内路标指引肝实质离断。笔者临床经验表明:通过选择合适手术策略能有效降低腹腔镜解剖性肝Ⅶ段切除术难度、提高手术安全性和可控性,同时保证肿瘤根治性效果。     

睫状前动脉的巨微解剖及其临床意义

对30只成人和6只新生儿眼球的睫状前动脉的数目、起点外径、长度、行径及侧支吻合进行观测.上、下、内睫状前动脉多为二支,各占76.7%;73.3%;83.3%.外睫状前动脉多为一支(76.6%).上、下、内、外睫状前动脉的长度分别为5.58土0.44mm;4.79士0.72mm;4.43土0. 76mm;8.00土1.07mm.起点外径分别为0.20mm;士0.04mm;0.I8士0.02mm;0.21土0.03mm.在巩膜表面和虹膜大环处睫状前动脉的侧支之间以及侧支与睫状后长动脉之间相互吻合,这些吻合在眼前节侧支循环方面起一定作用.文中对眼直肌手术时如何减少或避免睫状前动脉损伤等问题做了探讨.     

Motor reflex responses elicited by cutaneous stimulation in the regenerating nerve of man: Axon reflex or ephaptic response?

In 57 of 60 nerves (29 median and 31 ulnar) sutured at the wrist, forearm and arm, we recorded motor responses in thenar or hypothenar muscles by electrical stimulation of the corresponding fingers. Recordings were made at different times during the process of regeneration, ranging from 3 months up to 11 years. The responses showed a constant shape and latency to every stimulation (simple or repetitive). The latency was shorter the more distal the level of injury and the greater the elapsed time from the reinnervation. The point of "reflexion" of the responses is at or very near the line of nerve suture. The electrophysiological behavior of the responses fits well with either the criterion of axon reflex or ephaptic response. We discuss both possibilities and conclude that it is not possible, with the electrophysiological technique that we used, to distinguish between an axon reflex and an ephaptic response.     

Prechiasmatic Reordering of Fibre Diameter Classes in the Retinofugal Pathway of Ferrets

This study examines the distribution of fibre diameter classes at various sites along the retinofugal pathway of adult ferrets. Light microscopic observations were made on semi-thin sections, and regional fibre diameter spectra were constructed from diameter measurements taken from electron micrographs of thin sections of the intraorbital optic nerve (2.5 mm from the optic disc), the intracranial optic nerve (1 mm rostral to the fusion of the nerves), and the optic tract (just caudal to the optic chiasm).
Whereas diameter types are relatively evenly distributed behind the eye in the postoptic nerve, they begin to segregate along its prechiasmatic course. Within this prechiasmatic region, coarse and fine calibre fibres are confined increasingly to more ventral locations in the nerve, leaving a dorsal band populated predominantly by intermediate calibre fibres. In conjunction with this redistribution of axon size classes, the fascicular arrangement of axons which is present distally, changes to a non-fascicular organization. The prechiasmatic organization of fibre types approximates that found in the optic tract where the coarse and fine calibre fibres lie further ventrally towards the pial surface.
The prechiasmatic region can be viewed as a region of transition where the order of fibres in the nerve (retinotopic) starts to change to that present in the optic tract (chronotopic), resulting in the first-born beta cell axons becoming segregated dorsally, and rostral to the coarse and fine calibre classes which segregate at further caudal locations. Further, since the sorting of fibres according to diameter appears before the fibres reach the optic chiasm, the segregation of diameter classes is not dependent on the chiasmatic sorting of fibres according to their crossed or uncrossed course.     

RADIATION INDUCED PROGRESSIVE DECREASING IN THE EXPRESSION OF REVERSE TRANSCRIPTASE GENE OF hEST2 AND TELOMERASE ACTIVITY

Objectites. In order to identify the relationship between telomerase and the biological effect of radiation injury, and investigate the role of human telomerase catalytic subunit gene (hEST2) reverse tranacriptase(RT) seg-ment in the expression of telomerase activity. Methods. Tumor FIeLa cells, KB cells and A431 cells were employed to measure the change in telomeraseactivity after 60Co-ray irradiation at RNA level and protein level. Quantitative PCR and Northern blotting wereused to determine the expression of bEST2 RT segment that encodes seven motifs of the human telomeres, a PCR-besed telomeric repeat amplification protocol (TRAP)was used to assay telomerase activity after exposure toradiation. Results. Both of telomerase activity and the expression hEST2 RT segment were decreased with increasingdosage of radiation. In addition, testing the expression of motifs domain is similar to the measurement of telomerase activity. Conclusion. The detection of the hEST2 BT segment by Northern blotting and quantitative PCR are new methods for testing Uflomerase activity. Furthermore, radiation can cause a dose-dependent decrease in telomerase activity. The effect of radiation on telomerase is one possible reason for the death of cancer ceils after irradiation.     

一氧化氮内皮素-1与早期糖尿病肾病及中医药防治

近年发现一氧化氮(NO)和内皮素-1(ET-1)很可能构成一对具有拮抗作用的血管活性物质,在糖尿病肾病1期肾小球高滤过中起重要的调控作用。而中药对糖尿病早期异常肾血流动力学的改善作用的研究报告很少,且目前有关研究似显肤浅。     

Structure and evolution of neuronal wiring receptors and ligands

One of the fundamental properties of a neuronal circuit is the map of its connections. The cellular and developmental processes that allow for the growth of axons and dendrites, selection of synaptic targets, and formation of functional synapses use neuronal surface receptors and their interactions with other surface receptors, secreted ligands, and matrix molecules. Spatiotemporal regulation of the expression of these receptors and cues allows for specificity in the developmental pathways that wire stereotyped circuits. The families of molecules controlling axon guidance and synapse formation are generally conserved across animals, with some important exceptions, which have consequences for neuronal connectivity. Here, we summarize the distribution of such molecules across multiple taxa, with a focus on model organisms, evolutionary processes that led to the multitude of such molecules, and functional consequences for the diversification or loss of these receptors.     

Observations of the relationship between left ventricular aneurysm and ST segment elevation in patients with a first acute anterior Q wave myocardial infarction

Seventy-eight consecutive survivors of a first acute anteriorQ wave myocardial infarction (AMI) underwent two-dimensionalechocardiography (2D echo), colour Doppler echo and radionuclideangiography (RNA) for the diagnosis of left ventricular (LV)anteroapical aneurysm, in order to study the relationship ofthis complication to precordial ST segment elevation in thesepatients. The ST elevation (mm) in lead V₂, the maximum ST elevationin V₁-V₆ and the sum of ST elevation in V₁ to V₆ were calculated.LV aneurysm was present in 19 patients by 2D echo, of whom 12had a paradoxical systolic flow pattern (red and outward towardsthe transducer) at the apex. There was no difference between the mean ST elevation in V₂or the maximum ST elevation in V₁-V₆ in patients with and withoutan aneurysm, although the sum of ST elevations in V₁ to V₆ washigher in the former group (P<0.01). ST elevation of patientswith and without paradoxical systolic flow also did not differsignificantly. Wall motion abnormality (akinesis and dyskinesis)by 2D echo in the anterior wall was seen in 74% of patientswith and 36% of patients without an aneurysm (P<0.005), andin the septal region in 63% and 47% of respective patients (P-NS).There was no difference between the magnitude of ST elevationin subgroups of patients with ejection fraction (EF) 30% to40%, but the mean EF of patients with (23 ± 2.1%) andwithout a LV aneurysm (34 ± 1.3%) differed (P<0.001). It is concluded that precordial ST segment elevation does notclearly and in the diagnosis of an anteroapical LV aneurysm.It is related to akinesis and dyskinesis in anterior and septalregions inherent in patients with AMI and does not indicateimpaired LV function.