Are there Hebrews left?

The Samaritan sect in the Middle East traces its ancestry over a period of more than 2,000 years from the Biblical Samaritans. The Samaritans are the guardians of a unique and very ancient religious literature which together with other historical accounts makes their claim of such a length of existence probable. Comparison of blood group frequencies as well as other genetic markers (such as PTC sensitivity, color blindness and G6PD deficiency) indicate that the Samaritans are unlike any of the existing surrounding groups whom they might be expected to resemble. From comparison of anthropometric data the Samaritans appear to exhibit their own “typical” features which do not resemble those of any other Jewish or non-Jewish community in the Middle East. These differences support the contention that the Samaritans' separation and isolation from the communities is not a recent event. The possibility that the Samaritans today can be regarded as modern representatives of the ancient Hebrews and the living offspring of a particular branch of the Israelite kingdom is discussed.     

Bats and moths: what is there left to learn?

Abstract.  Over 14 families of moths have ears that are adapted to detect the ultrasonic echolocation calls of bats. On hearing a bat, these moths respond with an escape response that reduces their chances of being caught. As an evolutionary response, bats may then have evolved behavioural strategies or changes in call design to overcome the moth's hearing. The nature of this interaction is reviewed. In particular, the role of the echolocation calls of bats in the shaping of the structure, neurophysiology and behavioural responses of moths is discussed. Unresolved issues, such as the structural complexity of the moth's auditory system, the nature of temporal integration and the role of the non-auditory B cell, are described. Issues in which the interactions between bats and moths may be of more general interest to biologists, such as noise filtering within the central nervous system, protean behaviours and coevolution between predator and prey, are also discussed. The interaction between bats and moths has much to interest general biologists, and may provide a useful model in understanding the neurophysiological basis of behaviour, including protean escape behaviours. The validity of the term coevolution as applied to this system is discussed, as there is no doubt that the auditory system of moths is a response to the echolocation calls of bats, although the evolutionary response of bats to moths is more ambiguous.     

Ion flow regulates left–right asymmetry in sea urchin development

The degree of conservation among phyla of early mechanisms that pattern the left–right (LR) axis is poorly understood. Larvae of sea urchins exhibit consistently oriented LR asymmetry. The main part of the adult rudiment is formed from the left coelomic sac of larvae, the left hydrocoel. Although this left preference is conserved among all echinoderm larvae, its mechanism is largely not understood. Using two marker genes, HpNot and HpFoxFQ-like, which are asymmetrically expressed during larval development of the sea urchin Hemicentrotus pulcherrimus, we examined in this study the possibility that the recently discovered ion flux mechanism controls asymmetry in sea urchins as it does in several vertebrate species. Several ion-transporter inhibitors were screened for the ability to alter the expression of the asymmetric marker genes. Blockers of the H⁺/K⁺-ATPase (omeprazole, lansoprazole and SCH28080), as well as a calcium ionophore (A23187), significantly altered the normal sidedness of asymmetric gene expression. Exposure to omeprazole disrupted the consistent asymmetry of adult rudiment formation in larvae. Immuno-detection revealed that H⁺/K⁺-ATPase-like antigens in sea urchin embryos were present through blastula stage and exhibited a striking asymmetry being present in a single blastomere in 32-cell embryos. These results suggest that, as in vertebrates, endogenous spatially-regulated early transport of H⁺ and/or K⁺, and also of Ca²⁺, functions in the establishment of LR asymmetry in sea urchin development.Electronic Supplementary Material Supplementary material is available for this article at     

Is high-frequency repetitive transcranial magnetic stimulation of the left primary motor cortex superior to the stimulation of the left dorsolateral prefrontal cortex in fibromyalgia syndrome?

Objective: To investigate effectiveness of two different high-frequency repetitive transcranial magnetic stimulation (rTMS) protocols on pain, fatigue, quality of life (QoL) and depression in female patients with fibromyalgia.

Methods: Thirty patients were randomized into three groups. Fifteen sessions of 10?Hz (90% resting motor threshold-RMT, 1200 pulses) rTMS were applied to left primary motor cortex and left dorsolateral prefrontal cortex (DLPFC) in Group M1 (n:10) and Group DLPFC (n:10), respectively. Group sham (n?=?10) received 15 sessions of sham rTMS over 3?weeks. Visual Analogue Scale, Fibromyalgia Impact Questionnaire, Fatigue Severity Scale, Short-form 36, and Beck Depression Inventory were assessed at baseline and at the end of the treatments by a blinded-experienced assessor.

Results: Significant improvements in pain, QoL, and depression scores were observed in three groups. However, improvements in depression, physical functioning, physical role functioning, and general health perceptions were greater in active rTMS groups than in sham group. Emotional role functioning was only improved in Group M1. The decrease in VAS scores was significantly greater in Group M1 when compared to sham group. Change in physical role functioning was significantly greater in Group DLPFC than in Group M1.

Conclusions: Significant improvements in physical role functioning, physical functioning, depression, and general health perceptions were achieved in active rTMS groups. Further clinical studies on larger samples involving both sexes with longer follow-up durations are needed.     

Percutaneous closure of a left atrial appendage with relevant suture dehiscence

Atrial fibrillation is a widespread disease and highly relevant as it carries an extended risk for ischaemic stroke. Surgical closure of the left atrial appendage is routinely performed during open heart surgery in patients with atrial fibrillation with the aim of thromboembolic protection. In this report we present a successful percutaneous closure of a left atrial appendage, which showed clinically relevant suture dehiscence several years after surgical closure.     

基于JCI标准的医院质量管理体系建设

质量管理体系构建是医院质量管理的核心,也是“以病人为中心”的各项制度有效落实的根基。从剖析质量管理系统存在的问题入手,按照JCI医院评审标准,建立了全员参与、职责分明的四级质量管理体系及一体化的责任流程和监控体系;完善了不良事件上报管理体系,塑造了质量安全至上、精细化管理的价值理念;通过推广SPEAK方针,引导和鼓励患者及家属参与到质量持续改进中来。     

Is the lack of respiratory gating prejudicial for left breast TomoDirect treatments?

Background and purposeTomoDirect (TD) can only operate in free-breathing. The purpose of this study is to compare TD with breath-hold 3D conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) techniques for left breast treatments, and to determine if the lack of respiratory gating is a handicap for cardiac sparing.Materials and methods15 patients treated for left breast had two computed tomography simulation, in free breathing (FB) and in deep-inspiration breath-hold (DIBH). Four treatments were planned: TD-FB, 3DCRT-FB, 3DCRT-DIBH and IMRT-DIBH. Dose to PTV, heart, lungs, right breast and patient were compared.ResultsA slightly lower cardiac mean dose is found for 3DCRT-DIBH than for TD-FB group (1.99 Gy Vs 2.89 Gy, p = 0.0462), while no statistical difference is found for heart V₂₀. TD-FB plans show the best PTV dose homogeneity (0.053, p < 0.001) and the lowest left lung mean dose (5.16 Gy, p < 0.001). No major differences are found for the other organs.ConclusionsTomoDirect and breath-hold 3DCRT are complementary techniques for left breast treatments: for a minority of patients, respiratory gating is mandatory to lower cardiac dose; for the remaining majority of patients, TomoDirect achieves better PTV homogeneity and reduced left lung dose, with cardiac dose equivalent to 3DCRT-DIBH.     

Is human aging still mysterious enough to be left only to scientists?

The feasibility of reversing human aging within a matter of decades has traditionally been dismissed by all professional biogerontologists, on the grounds that not only is aging still poorly understood, but also many of those aspects that we do understand are not reversible by any current or foreseeable therapeutic regimen. This broad consensus has recently been challenged by the publication, by five respected experimentalists in diverse subfields of biogerontology together with three of the present authors, of an article (Ann NY Acad Sci 959, 452-462) whose conclusion was that all the key components of mammalian aging are indeed amenable to substantial reversal (not merely retardation) in mice, with technology that has a reasonable prospect of being developed within about a decade. Translation of that panel of interventions to humans who are already alive, within a few decades thereafter, was deemed potentially feasible (though it was not claimed to be likely). If the prospect of controlling human aging within the foreseeable future cannot be categorically rejected, then it becomes a matter of personal significance to most people presently alive. Consequently, we suggest that serious public debate on this subject is now warranted, and we survey here several of the biological, social and political issues relating to it.     

Two theories of origin of the land-plant sporophyte: Which is left standing?

Questions concerning the two competing theories of the development of alternating generations in land plants, the homologous theory and the antithetic theory, have never been fully resolved. In the majority of recent accounts there appears to have been increasing de facto support (if one considers the ontogenetic processes and phylogenetic consequences discussed) for the antithetic theory. However, this preference is usually not plainly stated (as such) in these discussions, and some support has also continued for the homologous theory. The crux of both theories (homologous and antithetic) centers upon how the sporophyte may have originated in the life cycle. One problem with the homologous theory is that it is not made explicit how the development of a dependent sporophyte could have occurred in the life cycle (when the precedent organisms are considered to have had free-living, putatively similar, gametophytes and sporophytes). The antithetic theory, by contrast, offers a definite ontogenetic mechanism or process (retention of the zygote on the gametophyte, delay of zygotic meiosis, with zygotic mitoses occurring first) by which a dependent sporophyte might have originated and persisted, in the context of a life cycle formerly lacking a sporophyte generation. Also, a review of a variety of evidence (morphological, cytological, biochemical, etc.) would appear to lend more support to the antithetic theory than to the homologous theory. In discussing types of algae now known to be most clearly related to land plants (i.e., charophytes, particularly advanced forms), the type of life cycle exhibited by these particular algae (haplontic, with zygotic meiosis; no sporophyte present) suggests that only an antithetic origin of the sporophyte in land plants is actually feasible.     

Vertebrate left and right: Finally a cascade,but first a flow?

Vertebrate development gives rise to systematic, normally reliably coordinated left-right asymmetries of body structure. This “handed asymmetry” of anatomy must take its ultimate origin from some chiral molecular assembly (one exhibiting no planes of symmetry and thus, having an intrinsic “handedness”) within the early embryo's cells. But which molecules are involved, how is their chiral property coordinately aligned among many cells, and how does it “seed” the differential cascades of gene expression that characterise right and left halves of the embryo? Recent molecular characterisations of mouse mutations that randomise or reverse body asymmetries have offered tantalising clues to the chiral initiator molecules, but the findings in a subsequent Cell paper (Nonaka S, Yosuke T, Okada Y, Takeda S, Harada K, Kanai Y, Kido M, Hirokawa N. Randomisation of left-right asymmetry due to loss of nodal cilia generating a leftward flow of extraembryonic fluid in mice lacking KIF3B motor protein. Cell 1998;95:829–837. [Reference 1]) may help us understand how the first gene expression asymmetries occur. BioEssays 21:537–541, 1999. © 1999 John Wiley & Sons, Inc.     

试析新医改背景下医院文化的重建

新医改明确了公立医院改革的方向,这必然会对公立医院文化产生重要影响。公立医院必须对医院文化进行转型重建,重塑医院和医生的伦理价值观,才能不断适应医改的新变化、新要求。本文从新医改给公立医院文化带来的影响与变化入手,论述了重建医院文化的重要意义,并指出了公立医院文化重建的路径与措施,即重塑医院精神文化,树立正确的价值取向;重塑制度文化,完善各项制度;加强物质文化重建,改善就医环境。     

中小型公立医院卫生人力资源配置存在问题与对策

随着医改的不断深入,中小型公立医院卫生人力资源配置面临着新的发展机遇和挑战,这就需要医院管理者对中小型公立医院的卫生人力资源进行深入思考。针对中小型公立医院卫生人力资源管理存在的诸多问题,从更新理念、人力规划、人才培养、构建团队、考核机制、契约机制以及医院文化等方面进行探讨,提出了卫生人力资源管理新策略。     

Extracellular proton depression of peak and late Na⁺ current in the canine left ventricle

Cardiac ischemia reduces excitability in ventricular tissue. Acidosis (one component of ischemia) affects a number of ion currents. We examined the effects of extracellular acidosis (pH 6.6) on peak and late Na(+) current (I(Na)) in canine ventricular cells. Epicardial and endocardial myocytes were isolated, and patch-clamp techniques were used to record I(Na). Action potential recordings from left ventricular wedges exposed to acidic Tyrode solution showed a widening of the QRS complex, indicating slowing of transmural conduction. In myocytes, exposure to acidic conditions resulted in a 17.3 ± 0.9% reduction in upstroke velocity. Analysis of fast I(Na) showed that current density was similar in epicardial and endocardial cells at normal pH (68.1 ± 7.0 vs. 63.2 ± 7.1 pA/pF, respectively). Extracellular acidosis reduced the fast I(Na) magnitude by 22.7% in epicardial cells and 23.1% in endocardial cells. In addition, a significant slowing of the decay (time constant) of fast I(Na) was observed at pH 6.6. Acidosis did not affect steady-state inactivation of I(Na) or recovery from inactivation. Analysis of late I(Na) during a 500-ms pulse showed that the acidosis significantly reduced late I(Na) at 250 and 500 ms into the pulse. Using action potential clamp techniques, application of an epicardial waveform resulted in a larger late I(Na) compared with when an endocardial waveform was applied to the same cell. Acidosis caused a greater decrease in late I(Na) when an epicardial waveform was applied. These results suggest acidosis reduces both peak and late I(Na) in both cell types and contributes to the depression in cardiac excitability observed under ischemic conditions.     

A fast computational model for circulatory dynamics: effects of left ventricle–aorta coupling

The course of diseases such as hypertension, systolic heart failure and heart failure with a preserved ejection fraction is affected by interactions between the left ventricle (LV) and the vasculature. To study these interactions, a computationally efficient, biophysically based mathematical model for the circulatory system is presented. In a four-chamber model of the heart, the LV is represented by a previously described low-order, wall volume-preserving model that includes torsion and base-to-apex and circumferential wall shortening and lengthening, and the other chambers are represented using spherical geometries. Active and passive myocardial mechanics of all four chambers are included. The cardiac model is coupled with a wave propagation model for the aorta and a closed lumped-parameter circulation model. Parameters for the normal heart and aorta are determined by fitting to experimental data. Changes in the timing and magnitude of pulse wave reflections by the aorta are demonstrated with changes in compliance and taper of the aorta as seen in aging (decreased compliance, increased diameter and length), and resulting effects on LV pressure–volume loops and LV fiber stress and sarcomere shortening are predicted. Effects of aging of the aorta combined with reduced LV contractile force (failing heart) are examined. In the failing heart, changes in aortic properties with aging affect stroke volume and sarcomere shortening without appreciable augmentation of aortic pressure, and the reflected pressure wave contributes an increased proportion of aortic pressure.