When does the good of the group override the advantage of the individual?

In a system of N populations of n reproductive individuals apiece, in which each population has constant variance v² and lasts L generations, group selection on a quantitative character has a reasonable chance of overriding selection within populations if (and only if) the populations never exchange migrants, each population is founded by colonists from a single parent population, and the number of populations exceeds the effective number of reproductive individuals per population. If each population derives from a single parent population, then the exchange of a single successful migrant per population per L generations can triple the strength of group selection required to overcome a given selection within populations. If populations exchange no migrants, then the derivation of one in every N populations from two equally represented parents (while the others all derive from a single parent) doubles the strength of group selection required to prevail. Group selection is accordingly likely to be effective only in certain categories of parasites.     

Stochastic simulations of the exponential-beta function as an assessment of the validity of the choice of the Wagner-Nelson method for the analysis of ¹³C-octanoic acid breath tests

A compartmental model that generates the exponential-beta function μkβ(1 - e(-kt))(β - 1)?e(-kt) in order to run stochastic simulations has been constructed. The mathematical considerations that lead to the development of the model and the comparison of its performance with real data sets obtained from the studies of gastric emptying in healthy volunteers using 13C-octanoic acid breath tests are demonstrated. Stochastic simulations have been used to introduce randomness. These confirmed the choice of an exponential-beta function to model the physiological system, as agreement was obtained between experimental and theoretical data. The comparisons were made by visual inspection only, as the intention was to demonstrate that the stochastic exponential-β model would generate the full range of observed curve shapes.     

Anterior fissure of the right liver — the third door of the liver

Background/Purpose

Although the anterior segment of the liver has been divided into segments 8 and 5, we have, during surgical or interventional procedures, occasionally encountered patients in whom the right anterior portal vein does not bifurcate into the superior and inferior branches. Thus, the in vivo anatomy of the right liver was reevaluated to clarify the segmental anatomy.

Methods

We evaluated the hepatic venous and portal ramification patterns, using three-dimensional images reconstructed from computed tomography. In addition, liver volumetry was performed.

Results

All branches arising from the anterior trunk were divided into two groups: the right ventral portal branches (RVP) and the right dorsal portal branches (RDP), and the anterior fissure vein crossed between the RVP and RDP. The ventral and dorsal regions of the anterior segment were approximately equal from a volumetric point of view.

Conclusions

The anterior segment seems to be divided into the ventral and dorsal segments by the anterior fissure, and we propose a reclassification of the right liver that divides the right liver into three segments. Dissection of the parenchyma along the anterior fissure makes the third door of the liver open, resulting in the exposing of all Glissonian pedicles of the right liver. The introduction of our segmental anatomy and surgical procedure will allow more systematic and limited liver resections.     

What is the role of radiotherapy in the treatment of mucosal melanoma of the head and neck?

Mucosal melanoma of the head and neck is a rare, poor prognosis tumour with a high tendency to recur locally and regionally after surgical resection. A number of centres have used radiotherapy to sterilize positive and close margins after non-radical surgery or to treat inoperable cases. The present article discusses the literature data to analyze the possible indications for radiotherapy in terms of patient selection and treatment strategy. In the majority of the available retrospective series, postoperative radiotherapy improves the local control of mucosal melanomas, but its effect on survival has not yet been sufficiently investigated. Radiobiological studies show a high heterogeneity in behaviour of irradiated melanoma cells and the clinical implications of this will be illustrated. In the future, a better understanding of the radiosensitivity of this rare tumour and the availability of new technical modalities might allow for a more profitable incorporation of radiotherapy into a multidisciplinary strategy.     

Autonomic Dysfunction of the β-Cell and the Pathogenesis of Obesity

Reviews in Endocrine and Metabolic Disorders -     

Genetics of inflammatory bowel disease: The beginning of the end or the end of the beginning?

Recent identification of the first susceptibility gene for Crohn's disease has led to increasing enthusiasm for the investigation and dissection of inflammatory bowel disease. In the future, identification of additional genes and careful correlation of the genetic background with clinical features of the disease will help to elucidate the causes and cure of inflammatory bowel disease. However, caution is still needed in the short term since our present knowledge has limited influence on clinical management. This review focuses on the genetic background of inflammatory bowel disease, the process of discovering the mutations of the NOD2/CARD15 gene in Crohn's disease patients, and the functional clues of the genetic variants of this gene in relation to clinical features.     

Parasitofauna of the nine-spined stickleback from the Gulf of Gdańsk and the mouth of Dead Vistula

Four species, one subspecies and one parasite marked to the genus were collected from the nine-spined stickleback Pungitius pungitius L. from the Gulf of Gdańsk and the mouth of Dead Vistula. Nine-spined stickleback was noted as a new host in Polish coastal water for five parasites: Glugea anomala (Microsporidia), Diplostomum spathaceum (Digenea-metacercariae) and Apatemon sp. (Digenea-incysted metacercariae), Hysterothylacium aduncum (Nematoda-third stage larvae) and Thersitina gasterostci (Copepoda). Earlier in this area have been obserwd only ciliates Tnchodina domerguei.     

What features of the pathological morphology of the liver increase the accuracy of diagnostic imaging for cirrhosis?

Journal of Gastroenterology -     

Ceremony for the inaugural issuance of the Journal of Geriatric Cardiology

The Journal of Geriatric Cardiology(JGC)started publication in September 2004.To announce thepublication of its first issue,a ceremony was held atChina Grand Hotel in Beijing on October 18~(th),2004during the 15~(th)Great Wall International Congress ofCardiology.Many guests were present at the ceremony.Editorial board members,such as Drs.Dayi HU,Zhongxiang LIN,Zhuming JIANG,Junheng LI,FangyiQIAN,etc participated in the ceremony.Some journalists     

Letter of the Editor-in-chief

Dear Friends and Colleagues, In this letter, I would like to celebrate the second anniversary of the Journal of Geriatric Cardiology (JGC). With the help of all of you, friends and colleagues, readers, editorials consultants, authors and editorial staff, the JGC was able to grow and publish many quality papers from the world. At first, Dr. Eugene Braunwald of Harvard Medical School wrote the foreword and then after, sent a congratu- latory note for the publication of the first issue. P…     

Why does the heart beat? The discovery of the electrical system of the heart

Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused "block" when cut and found that the sinus venosus was the area of first excitation of the heart. By examining serial embryologic sections, Wilhelm His, Jr, showed that a connective tissue sheet became a bundle connecting the upper and lower cardiac chambers, the bundle of His. Sunao Tawara traced the atrioventricular (AV) bundle of His backward to find a compact node of fibers at the base of the atrial septum and forward where it connected with the bundles of cells discovered by Purkinje in 1839. Tawara concluded that this "AV connecting system" originated in the AV node, penetrated the septum as the His bundle, and then divided into left and right bundle branches that terminated in the Purkinje fibers. Martin Flack and Arthur Keith studied the conduction system of a mole and found a structure in the sinoauricular junction that histologically resembled the AV node. They felt that this was where "the dominating rhythm of the heart normally begins" and named it the sinoauricular node in 1907. The ECG of Einthoven soon brought a new understanding to the complex electrical system that makes the heart beat. In 2006 and 2007, we celebrate the 100th anniversaries of the publication of the exciting discovery of the AV and sinus nodes, truly landmarks in our understanding of cardiac structure and physiology.