bluuebunny/crossref_metadata_2025 huggingface dataset:
Anatomy of the pig heart: comparisons with normal human cardiac structure
Authors: CRICK SIMON J. , SHEPPARD MARY N. , HO SIEW YEN , GEBSTEIN LIOR , ANDERSON ROBERT H.
Published: March 2003

Transgenic technology has potentially solved many of the immunological difficulties of using pig organs to support life in the human recipient. Nevertheless, other problems still remain. Knowledge of cardiac anatomy of the pig (Sus scrofa) is limited despite the general acceptance in the literature that it is similar to that of man. A qualitative analysis of porcine and human cardiac anatomy was achieved by gross examination and dissection of hearts with macrophotography. The porcine organ had a classic ‘Valentine heart’ shape, reflecting its location within the thorax and to the orientation of the pig's body (unguligrade stance). The human heart, in contrast, was trapezoidal in silhouette, reflecting man's orthograde posture. The morphologically right atrium of the pig was characterised by the tubular shape of its appendage (a feature observed on the left in the human heart). The porcine superior and inferior caval veins opened into the atrium at right angles to one another, whereas in man the orifices were directly in line. A prominent left azygous vein (comparable to the much reduced left superior caval or oblique vein in man) entered on the left side of the pig heart and drained via the coronary sinus. The porcine left atrium received only 2 pulmonary veins, whereas 4 orifices were generally observed in man. The sweep between the inlet and outlet components of the porcine right ventricle was less marked than in man, and a prominent muscular moderator band was situated in a much higher position within the porcine right ventricle compared with that of man. The apical components of both porcine ventricles possessed very coarse trabeculations, much broader than those observed in the human ventricles. In general, aortic‐mitral fibrous continuity was reduced in the outlet component of the porcine left ventricle, with approximately two‐thirds of the aortic valve being supported by left ventricular musculature. Several potentially significant differences exist between porcine and human hearts. It is important that these differences are considered as the arguments continue concerning the use of transgenic pig hearts for xenotransplantation.
NT‐3 modulates NPY expression in primary sensory neurons following peripheral nerve injury
Authors: STERNE G. D. , BROWN R. A. , GREEN C. J. , TERENGHI G.
Published: March 2003

Peripheral nerve transection induces significant changes in neuropeptide expression and content in injured primary sensory neurons, possibly due to loss of target derived neurotrophic support. This study shows that neurotrophin‐3 (NT‐3) delivery to the injured nerve influences neuropeptide Y (NPY) expression within dorsal root ganglia (DRG) neurons. NT‐3 was delivered by grafting impregnated fibronectin (500 ng/ml; NT group) in the axotomised sciatic nerve. Animals grafted with plain fibronectin mats (FN) or nerve grafts (NG) were used as controls. L4 and L5 DRG from operated and contralateral sides were harvested between 5 and 240 d. Using immunohistochemistry and computerised image analysis the percentage, diameter and optical density of neurons expressing calcitonin gene‐related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP) and NPY were quantified. Sciatic nerve axotomy resulted in significant reduction in expression of CGRP and SP, and significant upregulation of VIP and NPY (P<0.05 for ipsilateral vs contralateral DRG). By d 30, exogenous NT‐3 and nerve graft attenuated the upregulation of NPY (P<0.05 for NT and NG vs FN). However, NT‐3 administration did not influence the expression of CGRP, SP or VIP. The mean cell diameter of NPY immunoreactive neurons was significantly smaller in the NT‐3 group (P<0.05 for NT vs FN and NG) suggesting a differential influence of NT‐3 on larger neurons. The optical densities of NPY immunoreactive neurons of equal size were the same in each group at any time point, indicating that the neurons responding to NT‐3 downregulate NPY expression to levels not detectable by immunohistochemistry. These results demonstrate that targeted administration of NT‐3 regulates the phenotype of a NPY‐immunoreactive neuronal subpopulation in the dorsal root ganglia, a further evidence of the trophic role of neurotrophins on primary sensory neurons.
Pathological bone changes in the mandibles of wild red deer (Cervus elaphus L.) exposed to high environmental levels of fluoride
Authors: SCHULTZ MICHAEL , KIERDORF UWE , SEDLACEK FRANTISEK , KIERDORF HORST
Published: March 2003

A macroscopic, microscopic and scanning electron microscope study was performed on the pathological bone changes of the mandibles of wild red deer (n=61) exhibiting severe dental fluorosis. The animals originated from a highly fluoride polluted area in Central Europe (Ore mountains and their southern foreland, Czech‐German border region) and constituted 11.2% of the studied red deer sample (n=545) from this area. Pathologically increased wear and fracture of fluorosed teeth caused a variety of mandibular bone alterations, including periodontal breakdown, periostitis, osteitis and chronic osteomyelitis. As a further consequence of severe dental attrition, opening of the pulp chamber and formation of periapical abscesses were occasionally observed. In case of severe periodontal breakdown, loss of teeth from the mandibles was found. In addition to the inflammatory bone changes, the occurrence of osteofluorotic alterations was also diagnosed in the specimens with the highest bone fluoride concentrations (>4000 mg F−/kg dry wt). These changes comprised extended apposition of periosteal bone onto the mandibular cortex as well as deformation of the mandibular body, which was attributed to a fluoride‐induced osteomalacia. The present study provided circumstantial evidence that, in addition to fluoride induced dental lesions, the occurrence of marked periodontal disease and tooth loss is an important factor responsible for a reduction of life expectancy in severely fluorotic wild red deer.
Structure, distribution and innervation of muscle spindles in avian fast and slow skeletal muscle
Authors: OVALLE WILLIAM K. , DOW PIERRE R. , NAHIRNEY PATRICK C.
Published: March 2003

Muscle spindles in 2 synergistic avian skeletal muscles, the anterior (ALD) and posterior (PLD) latissimus dorsi, were studied by light and electron microscopy to determine whether morphological or quantitative differences existed between these sensory receptors. Differences were found in the density, distribution and location of muscle spindles in the 2 muscles. They also differed with respect to the morphology of their capsules and intracapsular components. The slow ALD possessed muscle spindles which were evenly distributed throughout the muscle, whereas in the fast PLD they were mainly concentrated around the single nerve entry point into the muscle. The muscle spindle index (number of spindles per gram wet muscle weight) in the ALD was more than double that of its fast‐twitch PLD counterpart (130.5±2.0 vs 55.4±2.0 respectively, n=6). The number of intrafusal fibres per spindle ranged from 1 to 8 in the ALD and 2 to 9 in the PLD, and their diameters varied from 5.0 to 16.0 μm and 4.5 to 18.5 μm, respectively. Large diameter intrafusal fibres were more frequently encountered in spindles of the PLD. Unique to the ALD was the presence of monofibre muscle spindles (12.7% of total spindles observed in ALD) which contained a solitary intrafusal fibre. In muscle spindles of both the ALD and PLD, sensory nerve endings terminated in a spiral fashion on the intrafusal fibres in their equatorial regions. Motor innervation was restricted to either juxtaequatorial or polar regions of the intrafusal fibres. Outer capsule components were extensive in polar and juxtaequatorial regions of ALD spindles, whereas inner capsule cells of PLD spindles were more numerous in juxtaequatorial and equatorial regions. Overall, muscle spindles of the PLD exhibited greater complexity with respect to the number of intrafusal fibres per spindle, range of intrafusal fibre diameters and development of their inner capsules. It is postulated that the differences in muscle spindle density and structure observed in this study reflect the function of the muscles in which they reside.
The effect of the timing of ethanol exposure during early postnatal life on total number of Purkinje cells in rat cerebellum
Authors: MIKI TAKANORI , HARRIS SIMON , WILCE PETER , TAKEUCHI YOSHIKI , BEDI KULDIP S.
Published: March 2003

We have previously shown that exposing rats to a high dose of ethanol on postnatal d 5 can affect Purkinje cell numbers in the cerebellum whilst similar exposure on d 10 had no such effect. The question arose whether a longer period of ethanol exposure after d 10 could produce loss of Purkinje cells. We have examined this question by exposing young rats to a relatively high dose (∼420–430 mg/dl) of ethanol for 6 d periods between the ages of either 4 and 9 d or 10 and 15 d of age. Exposure was carried out by placing the rats in an ethanol vapour chamber for 3 h per day during the exposure period. Groups of ethanol‐treated (ET), separation controls (SC) and mother‐reared controls (MRC) were anaesthetised and killed when aged 30 d by perfusion with buffered 2.5% glutaraldehyde. Stereological methods were used to determine the numbers of Purkinje cells in the cerebellum of each rat. MRC, SC and rats treated with ethanol between 10–15 d of age each had, on average, about 254–258 thousand cerebellar Purkinje cells; the differences between these various groups were not statistically significant. However, the rats treated with ethanol vapour between 4–9 d of age had an average of only about 128000±20000 Purkinje cells per cerebellum. This value was significantly different from both the MRC and group‐matched SC animals. It is concluded that the period between 4 and 9 d of age is an extremely vulnerable period during which the rat cerebellar Purkinje cells are particularly susceptible to the effects of a high dose of ethanol. However, a similar level and duration of ethanol exposure commencing after 10 d of age has no significant effect on Purkinje cell numbers.
The surface contour of articular cartilage in an intact, loaded joint
Authors: CLARK J. M. , NORMAN A. G. , KÄÄB M. J. , NÖTZLI H. P.
Published: March 2003

The friction coefficients measured in diarthrodial joints are small. Theories of joint lubrication attribute this efficiency to entrapment or movement of synovial fluid, yet anatomical models of the surface are based on studies of isolated fragments of cartilage, not functional joints. To investigate the functional interrelationship of joint surfaces and synovial fluid, the ultrastructure of loaded joints was examined. Twenty‐four New Zealand white rabbit knee joints were loaded either statically or moved ex vivo using simulated muscle forces and then plunge‐frozen under load. After fixation in the frozen/loaded state by freeze‐substitution fixation, the medial joint compartments were embedded in epoxy resin while still articulated. Bone was trimmed away from the articular surfaces, permitting the cartilage to be sectioned for light and electron microscopy. These joint surfaces were then compared with controls which were not loaded, not moved or had been disarticulated prior to embedding. Articular surfaces of loaded joints were smooth at magnifications from ×35 to ×7500, whereas the tibial surfaces of nonloaded joints were irregular. Small pools of joint fluid were observed at the meniscal edge and beneath the anterior horn of the meniscus. At magnifications of ×40000, the joint surfaces were separated by a uniform 100 nm space containing fluid. An amorphous, electron dense articular surface lamina was present but, when loaded, was thicker and flatter than previously reported. No surface pits or bumps were visible in embedded, loaded joints. This is the first ultrastructural study of intact loaded joints. The findings suggest that fluid film lubrication is present in diarthrodial joints, but the fluid sequestration postulated in several models is not apparent.
Distribution patterns of vimentin‐immunoreactive structures in the human prosencephalon during the second half of gestation
Authors: ULFIG NORBERT , NEUDÖRFER FRANK , BOHL JÜRGEN
Published: March 2003

Neuronal migration is guided by long radially oriented glial fibres. During late stages of development radial glial cells are transformed into astrocytes. A predominant intermediate filament protein within radial glial cells and immature astrocytes is vimentin. In this study fetal brain sections were used to demonstrate the transient features of vimentin‐positive radial glia. In the lower half of the cerebral wall of the 6th gestational month bundles, curvature, and crossing of vimentin‐positive fibres are regularly seen. Moreover, fibres terminating on vessels are observed. In the upper half fibres are radially oriented; when ascending towards the pial surface the number and diameter of fibres appears conspicuously decreased. Radially aligned fibres display numerous varicosities. In the 8th month the bulk of vimentin‐positive fibres is encountered next to the ganglionic eminence and below isocortical cerebral fissures. The dentate gyrus is conspicuous due to its high amount of immunolabelled fibres. Furthermore, densely packed fibres are visible within the internal and external capsule and in the vicinity of the anterior commissure. Radial glial somata are found in the proliferative areas as well as in the adjacent white matter. In the latter location bipolar, monopolar and stellate vimentin‐positive cells are present. The results demonstrate an area‐specific distribution pattern of vimentin‐positive structures which can be correlated with migrational events. Areas maturing late in development for instance, reveal dense immunolabelling in the 8th month. The orientation and position of radial fibres point to an additional developmental role of these fibres, i.e. their involvement in the guidance of growing axons. Moreover, the arrangement and morphology of vimentin‐positive fibres, such as retraction of fibres or occurrence of varicosities, are indicative of degenerative events. Accordingly, a transformation of radial glial somata, their displacement towards the white matter and finally the growth of stellate processes can clearly be demonstrated.
Morphological variation in great ape and modern human mandibles
Authors: HUMPHREY L. T. , DEAN M. C. , STRINGER C. B.
Published: March 2003

Adult mandibles of 317 modern humans and 91 great apes were selected that showed no pathology. Adult mandibles of Pan troglodytes troglodytes, Pongo pygmaeus pygmaeus and Gorilla gorilla gorilla and from 2 modern human populations (Zulu and Europeans from Spitalfields) were reliably sexed. Thirteen measurements were defined and included mandibular height, length and breadth in representative positions. Univariate statistical techniques and multivariate (principal component analysis and discriminant analysis) statistical techniques were used to investigate interspecific variability and sexual dimorphism in human and great ape mandibles, and intraspecific variability among the modern human mandibles. Analysis of interspecific differences revealed some pairs of variables with a tight linear relationship and others where Homo and the great apes pulled apart from one another due to shape differences. Homo and Pan are least sexually dimorphic in the mandible, Pan less so than Homo sapiens, but both the magnitude of sexual dimorphism and the distribution of sexually dimorphic measurements varied both among and between modern humans and great apes. Intraspecific variation among the 10 populations of modern humans was less than that generally reported in studies of crania (74.3% of mandibles were correctly classified into 1 of 10 populations using discriminant functions based on 13 variables as compared with 93% of crania from 17 populations based on 70 variables in one extensive study of crania). A subrecent European population (Poundbury) emerged as more different from a recent European population (Spitalfields) than other more diverse modern populations were from each other, suggesting considerable morphological plasticity in the mandible through time. This study forms a sound basis on which to explore mandibular variation in Neanderthals, early Homo sapiens and other more ancient fossil hominids.
Location of the spinal nucleus of the accessory nerve in the human spinal cord
Authors: ROUTAL R. V. , PAL G. P.
Published: March 2003

The segmental extent and topography of the spinal nucleus of the accessory nerve (SNAN) was investigated in the adult human spinal cord. Transverse sections of segments between the lower medulla and C6 were stained with cresyl violet and the motor cell columns identified according to the numerical locations defined by Elliott (1942). The segmental extent and topography of the cervical part of column 2 resembled that previously described for the SNAN of primates.
If bone is the answer, then what is the question?
Authors: HUISKES R.
Published: March 2003

In the 19th century, several scientists attempted to relate bone trabecular morphology to its mechanical, load‐bearing function. It was suggested that bone architecture was an answer to requirements of optimal stress transfer, pairing maximal strength to minimal weight, according to particular mathematical design rules. Using contemporary methods of analysis, stress transfer in bones was studied and compared with anatomical specimens, from which it was hypothesised that trabecular architecture is associated with stress trajectories. Others focused on the biological processes by which trabecular architectures are formed and on the question of how bone could maintain the relationship between external load and architecture in a variable functional environment. Wilhelm Roux introduced the principle of functional adaptation as a self‐organising process based in the tissues. Julius Wolff, anatomist and orthopaedic surgeon, entwined these 3 issues in his book The Law of Bone Remodeling (translation), which set the stage for biomechanical research goals in our day. ‘Wolff's Law’ is a question rather than a law, asking for the requirements of structural optimisation. In this article, based on finite element analysis (FEA) results of stress transfer in bones, it is argued that it was the wrong question, putting us on the wrong foot. The maximal strength/minimal weight principle does not provide a rationale for architectural formation or adaptation; the similarity between trabecular orientation and stress trajectories is circumstantial, not causal. Based on computer simulations of bone remodelling as a regulatory process, governed by mechanical usage and orchestrated by osteocyte mechanosensitivity, it is shown that Roux's paradigm, conversely, is a realistic proposition. Put in a quantitative regulatory context, it can predict both trabecular formation and adaptation. Hence, trabecular architecture is not an answer to Wolff's question, in the sense of this article's title. There are no mathematical optimisation rules for bone architecture; there is just a biological regulatory process, producing a structure adapted to mechanical demands by the nature of its characteristics, adequate for evolutionary endurance. It is predicted that computer simulation of this process can help us to unravel its secrets.
Anatomical variations in the human paranasal sinus region studied by CT
Authors: PÉREZ‐PIÑAS I. , SABATÉ J. , CARMONA A. , CATALINA‐HERRERA C. J. , JIMÉNEZ‐CASTELLANOS J.
Published: March 2003

A precise knowledge of the anatomy of the paranasal sinuses is essential for the clinician. Conventional radiology does not permit a detailed study of the nasal cavity and paranasal sinuses, and has now largely been replaced by computerised tomographic (CT) imaging. This gives an applied anatomical view of the region and the anatomical variants that are very often found. The detection of these variants to prevent potential hazards is essential for the use of current of endoscopic surgery on the sinuses. In the present work, we have studied the anatomical variants observed in the nasal fossae and paranasal sinuses in 110 Spanish subjects, using CT in the coronal plane, complemented by horizontal views. We have concentrated on the variants of the nasal septum, middle nasal concha, ethmoid unciform process and ethmoid bulla, together with others of lesser frequency. The population studied showed great anatomical variability, and a high percentage (67%) presented one or more anatomical variants. Discounting agger nasi air cells and asymmetry of both cavities of the sphenoidal sinus, which were present in all our cases, the variations most often observed were, in order, deviation of the nasal septum, the presence of a concha bullosa, bony spurs of the nasal septum and Onodi air cells.
The anatomy of language: contributions from functional neuroimaging
Authors: PRICE CATHY J.
Published: March 2003

This article illustrates how functional neuroimaging can be used to test the validity of neurological and cognitive models of language. Three models of language are described: the 19th Century neurological model which describes both the anatomy and cognitive components of auditory and visual word processing, and 2 20th Century cognitive models that are not constrained by anatomy but emphasise 2 different routes to reading that are not present in the neurological model. A series of functional imaging studies are then presented which show that, as predicted by the 19th Century neurologists, auditory and visual word repetition engage the left posterior superior temporal and posterior inferior frontal cortices. More specifically, the roles Wernicke and Broca assigned to these regions lie respectively in the posterior superior temporal sulcus and the anterior insula. In addition, a region in the left posterior inferior temporal cortex is activated for word retrieval, thereby providing a second route to reading, as predicted by the 20th Century cognitive models. This region and its function may have been missed by the 19th Century neurologists because selective damage is rare. The angular gyrus, previously linked to the visual word form system, is shown to be part of a distributed semantic system that can be accessed by objects and faces as well as speech. Other components of the semantic system include several regions in the inferior and middle temporal lobes. From these functional imaging results, a new anatomically constrained model of word processing is proposed which reconciles the anatomical ambitions of the 19th Century neurologists and the cognitive finesse of the 20th Century cognitive models. The review focuses on single word processing and does not attempt to discuss how words are combined to generate sentences or how several languages are learned and interchanged. Progress in unravelling these and other related issues will depend on the integration of behavioural, computational and neurophysiological approaches, including neuroimaging.
Anatomy of the cystic artery arising from the gastroduodenal artery and its choledochal branch—a case report
Authors: SARKAR A. K. , ROY T. S.
Published: March 2003

Variations in the branching pattern of the common hepatic artery often occur and may be encountered during cholecystectomy. Variants of the cystic artery, its branches and relations with the biliary structures and blood vessels emphasise the importance of arterial dissection in biliary surgery. In this study, a rare variant of the cystic artery and its choledochal branch is described. The cystic artery arose from the gastroduodenal artery, passed anterior to structures in the free margin of lesser omentum and travelled a long distance before supplying the gall bladder. A long choledochal branch was noted accompanying the common bile duct. Surgical implications of this variation of the cystic and choledochal arteries are discussed.
Differences between human and mouse alpha‐fetoprotein expression during early development
Authors: JONES ELIZABETH A. , CLEMENT‐JONES MARK , JAMES OLIVER F. W. , WILSON DAVID I.
Published: March 2003

Alpha‐fetoprotein (AFP) is the major serum protein during development. AFP is one of the earliest proteins to be synthesised by the embryonic liver. The synthesis of AFP decreases dramatically after birth and only trace amounts are expressed in the adult liver. The tissue distribution of AFP in early human embryogenesis has not been defined. We have studied the expression pattern of AFP mRNA in human and mouse embryos by in situ hybridisation. In humans, AFP is expressed in the hepatic diverticulum at 26 d postovulation as it differentiates from the foregut endoderm (i.e. in the most primitive hepatocytes). It is also expressed in the endoderm of the gastrointestinal tract and in the yolk sac at this age. AFP is subsequently expressed in the mesonephros and transiently in the developing pancreas. In the mouse, no expression of AFP was observed in the mesonephros but other sites of expression were similar. Thus AFP has a distinct temporospatial expression pattern during the embryonic period and this differs between human and mouse species. It is interesting that AFP is expressed by tumours such as primitive gastrointestinal, renal cell and pancreatic tumours as well as those of hepatocyte origin. This distribution reflects the sites of AFP expression during development.
Frequency variations of discrete cranial traits in major human populations. I. Supernumerary ossicle variations
Authors: HANIHARA TSUNEHIKO , ISHIDA HAJIME
Published: March 2003

Four supernumerary ossicle variations—the ossicle at the lambda, the parietal notch bone, the asterionic bone, and the occipitomastoid bone—were examined for laterality differences, intertrait correlations, sex differences, and between group variations in the samples from around the world. Significant laterality differences were not detected in almost all samples. In some pairs of traits, significant association of occurrence were found. Several geographic samples were sexually dimorphic with respect to the asterionic bone and to a lesser extent for the parietal notch bone. East/Northeast Asians including the Arctic populations in general had lower frequencies of the 4 accessory ossicles. Australians, Melanesians and the majority of the New World peoples, on the other hand, generally had high frequencies. In the western hemisphere of the Old World, Subsaharan Africans had relatively high frequencies. Except for the ossicle at the lambda, the distribution pattern in incidence showed clinal variation from south to north. Any identifiable adaptive value related to environmental or subsistence factors may be expressed in such clinal variation. This may allow us to hypothesise that not only mechanical factors but a founder effect, genetic drift, and population structure could have been the underlying causes for interregional variation and possible clines in the incidences of the accessory ossicles.
Regeneration as an evolutionary variable
Authors: BROCKES JEREMY P. , KUMAR ANOOP , VELLOSO CRISTIANA P.
Published: March 2003

abstract

Regeneration poses a distinctive set of problems for evolutionary biologists, but there has been little substantive progress since these issues were clearly outlined in the monograph of T. H. Morgan (1901). The champions at regeneration among vertebrates are the urodele amphibians such as the newt, and we tend to regard urodele regeneration as an exceptional attribute. The ability to regenerate large sections of the body plan is widespread in metazoan phylogeny, although it is not universal. It is striking that in phylogenetic contexts where regeneration occurs, closely related species are observed which do not possess this ability. It is a challenge to reconcile such variation between species with a conventional selective interpretation of regeneration. The critical hypothesis from phylogenetic analysis is that regeneration is a basic, primordial attribute of metazoans rather than a mechanism which has evolved independently in a variety of contexts. In order to explain its absence in closely related species, it is postulated to be lost secondarily for reasons which are not understood. Our approach to this question is to compare a differentiated newt cell with its mammalian counterpart in respect of the plasticity of differentiation.
The development and evolution of crossveins in insect wings
Authors: MARCUS JEFFREY M.
Published: March 2003

abstract

The formation of crossveins inDrosophilawas an important early case study in understanding the role of the environment in the development and evolution of morphological structures. More recent work has shown that signalling processes play a crucial role in the formation of crossveins inDrosophilaand that the interaction of a heat shock factor, Hsp90, with components of signal transduction pathways may account for the sensitivity of these structures to environmental perturbations. A new model for the development of crossveins is presented that divides the formation of crossveins into 3 separate stages. First, the number and placement of the crossveins is determined by signalling along the proximal‐distal axis of the wing. This signal may involve the cdc42 gene product and the Jun‐N‐terminal Kinase signal transduction pathway. Then, during the second stage, an inductive signal from the dorsal wing epithelium is sent to the ventral wing epithelium at locations specified by the first signal. The second signal appears to involve theBMP‐like signalling pathway. Finally, in the third stage, a domain of vein competent cells is defined by the signalling from the EGF‐receptor‐Map Kinase signal transduction pathway, and the exact location of the veins is eventually determined within that domain by Notch‐Delta signalling interactions. By altering components of these 3 stages, insects can independently regulate the presence or absence, the number and placement, and the thickness and flexibility of the crossveins. This capacity for the modulation of crossvein structure in many different ways may have contributed to the evolution of different modes of insect flight.
The sternalis muscle in the Bulgarian population: classification of sternales
Authors: JELEV L. , GEORGIEV G. , SURCHEV L.
Published: March 2003

The sternalis muscle (musculus sternalis) is the name usually given to this common anatomical variant, but the terms ‘episternalis’, ‘presternalis’, ‘sternalis brutorum’, ‘rectus thoracis’, ‘rectus sterni’, ‘superficial rectus abdominis’ and ‘japonicus’ have also been used in the literature (for reviews see Le Double, 1879; Calori, 1888; Pichler, 1911; Blees, 1968). According to Turner (1867), Cabrolius was the first, in 1604, to describe sternalis. Nevertheless this muscle is often unknown even in clinical practice (Bailey & Tzarnas, 1999; Vandeweyer, 1999).

Thus far, investigations on the incidence of sternalis have been made both in large populations such as the American (Barlow, 1935) and small populations, for example in Taiwan (Shen et al. 1992; Jeng & Su, 1998). In Europe, all studies on the frequency of this muscle have been made amongst subpopulations in Western (e.g. Cunningham, 1888; Le Double, 1890, 1897) and Northern Europe (Gruber, 1860) although the reported frequencies have been quite different. There is a lack of information about sternalis in Eastern European populations. We therefore present data from a study on the incidence of sternalis muscle in Bulgaria.
Systematic reviews of treatment for inflammatory demyelinating neuropathy*
Authors: Hughes R. A. C.
Published: March 2003

This review describes the progress made in preparing Cochrane systematic reviews of randomized controlled trials for Guillain–Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN) and the demyelinating neuropathies associated with paraproteins. The discovery of antibodies against myelin and axolemmal glycolipids and proteins has not yet replaced the clinicopathological classification on which treatment trials have been based. Systematic reviews have endorsed the equivalence of plasma exchange (PE) and intravenous immunoglobulin (IVIg) and the lack of efficacy of steroids in GBS. Systematic reviews have also endorsed the value of steroids, PE and IVIg in CIDP but randomized controlled trials have only shown benefit from IVIg in MMN. There is a paucity of evidence concerning the efficacy of treatments in paraproteinaemic demyelinating neuropathy apartment from small trials showing short‐term benefit from PE or IVIg. There is a lack of good quality controlled trials of immunosuppressive agents in any of these conditions. As the number of treatment trials increases, Cochrane systematic reviews will be an increasingly valuable resource for summarizing the evidence from randomised controlled trials on which to base clinical practice. They already demonstrate major deficiencies in the existing evidence base.
Aquaporin water channels and endothelial cell function*
Authors: Verkman A. S.
Published: March 2003

The aquaporins (AQP) are a family of homologous water channels expressed in many epithelial and endothelial cell types involved in fluid transport. AQP1 protein is strongly expressed in most microvascular endothelia outside of the brain, as well as in endothelial cells in cornea, intestinal lacteals, and other tissues. AQP4 is expressed in astroglial foot processes adjacent to endothelial cells in the central nervous system. Transgenic mice lacking aquaporins have been useful in defining their role in mammalian physiology. Mice lacking AQP1 manifest defective urinary concentrating ability, in part because of decreased water permeability in renal vasa recta microvessels. These mice also show a defect in dietary fat processing that may involve chylomicron absorption by intestinal lacteals, as well as defective active fluid transport across the corneal endothelium. AQP1 might also play a role in tumour angiogenesis and in renal microvessel structural adaptation. However, AQP1 in most endothelial tissues does not appear to have a physiological function despite its role in osmotically driven water transport. For example, mice lacking AQP1 have low alveolar‐capillary water permeability but unimpaired lung fluid absorption, as well as unimpaired saliva and tear secretion, aqueous fluid outflow, and pleural and peritoneal fluid transport. In the central nervous system mice lacking AQP4 are partially protected from brain oedema in water intoxication and ischaemic models of brain injury. Therefore, although the role of aquaporins in epithelial fluid transport is in most cases well‐understood, there remain many questions about the role of aquaporins in endothelial cell function. It is unclear why many leaky microvessels strongly express AQP1 without apparent functional significance. Improved understanding of aquaporin‐endothelial biology may lead to novel therapies for human disease, such as pharmacological modulation of corneal fluid transport, renal fluid clearance and intestinal absorption.
Transforming growth factor‐beta 2 heterozygous mutant mice exhibit Cowper's gland hyperplasia and cystic dilations of the gland ducts (Cowper's syringoceles)
Authors: Dünker Nicole , Aumüller Gerhard
Published: March 2003

Analyses of mutant mice with a deletion for the transforming growth factor beta 2 (Tgfβ2) gene revealed cysts in the perineal/scrotal region of male mice. We present evidence from in situ, light and electron microscopy that the cysts observed in Tgfβ2+/– heterozygous mice males derive from Cowper's gland tissue. The Cowper's glands of Tgfβ2+/– heterozygous mutant mice display all steps of glandular hyperplasia and cystic dilation. TGF‐β isoforms and TGF‐β receptor (TβR‐II) were localized immunocytochemically in sections of Cowper's glands. TGF‐β2 and TGF‐β3 were located predominantly in myoepithelial cells of the Cowper's gland whereas the TβRII was found in the plasma membrane of the acinar cells. TUNEL‐assays revealed that apoptotic cell death is significantly reduced in Cowper's glands of Tgfβ2+/– heterozygous mutant mice. The fact that Tgfβ2+/– heterozygous mutant mice exhibit hyperplasia of Cowper's gland epithelium and Cowper's gland cysts suggests a disturbance of epithelial–stromal interaction most likely due to reduced TGF‐β2 level, accompanied by a significant decrease in apoptosis.
Genetic disorders of palm skin and nail
Authors: McLean W. H. Irwin
Published: March 2003

The outer part of the skin, the epidermis, is specialized to protect the human body from its environment. Because of the high levels of physical stress experienced by the human hand in everyday use, the epidermis of the hand is especially toughened. In particular, the epidermis of the palm is highly specialized to resist mechanical trauma. Like the epidermis, the nails are composed of specialized epithelial cells and are especially strong. In recent years it has become apparent that the physical strength of epithelial cells comes from the keratin cytoskeleton – a dense meshwork of filaments extending throughout the cytoplasm. Keratins are a large family of intermediate filament proteins encoded by more than 50 distinct genes in humans. These different keratin genes are expressed in well‐defined combinations in specific epithelial tissues. Several keratin genes are expressed in palmoplantar epidermis and in the stratified epithelia of the nail bed. Genetic mutations in these genes lead to fragility of these tissues and result in a range of genetic disorders characterized by blistering and thickening of palm and sole skin and/or nails. Study of these diseases has shed new light on the vital structural role of keratins in maintaining the integrity of epithelial cells.
Evolution of the human hand: the role of throwing and clubbing
Authors: Young Richard W.
Published: March 2003

It has been proposed that the hominid lineage began when a group of chimpanzee‐like apes began to throw rocks and swing clubs at adversaries, and that this behaviour yielded reproductive advantages for millions of years, driving natural selection for improved throwing and clubbing prowess. This assertion leads to the prediction that the human hand should be adapted for throwing and clubbing, a topic that is explored in the following report. It is shown that the two fundamental human handgrips, first identified by J. R. Napier, and named by him the ‘precision grip’ and ‘power grip’, represent a throwing grip and a clubbing grip, thereby providing an evolutionary explanation for the two unique grips, and the extensive anatomical remodelling of the hand that made them possible. These results are supported by palaeoanthropological evidence.
NADH‐O2 oxidoreductase activity and mRNA expression of complex I (51 kDa, ND1) in postnatal intrinsic muscle of rat tongue
Authors: Fujita Toshiya , Sato Iwao
Published: March 2003

Complex I is one of the respiratory chain enzymes related to NADH dehydrogenase and is an encoded gene product derived from both nuclear and mitochondrial genomes. Transcription levels of ND1 (mitochondrial) and 51 kDa (nuclear) subunits of complex I in the postnatal development of the intrinsic muscle in rat tongues were determined by Northern blot analysis. Enzyme activity levels were determined by NADH staining with tetrazolum salt, and oxygen consumption of NADH‐O2 oxidoreductase activity using a Clark‐type electrode. The detailed structure of the mitochondria was observed using electron microscopy. The cross‐sectional area of the mitochondria gradually increased during postnatal development, and the cristae also became complex, despite the length of mitochondria in muscle fibre being constant. The mitochondria density increased from birth to 15 days of age, and declined slightly afterwards. This pattern of density resembled that of NADH‐O2 oxidoreductase activity. The level of mRNA for ND1 through Northern blot analysis gradually increased from birth to 15 days of age and was highest at 21 days. For 51 kDa, the level was highest at 0 days and fell thereafter to a constant low. This suggests that the production of NADH dehydrogenase is limited by 51 kDa of Complex I derived from nuclear genomes rather than by the increase in mitochondria and composition of muscle fibre types due to changes in feeding behaviour.
Uptake and metabolism of sulphur dioxide by Arabidopsis thaliana
Authors: VAN DER KOOIJ T. A. W. , DE KOK L. J. , HANEKLAUS S. , SCHNUG E.
Published: March 2003

Arabidopsis thaliana (L.) Heynh. was exposed to various concentrations of SO2 during almost the entire life cycle. No negative effects of SO2 on shoot biomass production were observed. There was a linear relation between the deposition of SO2 and the atmospheric SO2 concentration. Sulphur accumulated substantially in the shoots upon SO2 exposure. SO2 was either oxidized to sulphate or converted into extra organic sulphur compounds in a sulphate to organic sulphur ratio of 3:1, independently of the atmospheric SO2 concentration. Exposure to SO2resulted in an increase in water soluble non‐protein sulphydryl content and a slight increase in the amount of glucosinolates, but both of these play a minor role as sinks for the excess sulphur. The ratio of total nitrogen to total sulphur decreased upon SO2, exposure as a result of the increased sulphate content. The organic nitrogen to organic sulphur ratio did not change upon SO2 exposure, indicating no changes in the composition of sulphur‐containing compounds.
A comparative study of modern and fossil cone scales and seeds of conifers: a geochemical approach
Authors: STANKIEWICZ B. ARTUR , MASTALERZ MARIA , KRUGE MICHAEL A. , VAN BERGEN PIM F. , SADOWSKA ANNA
Published: March 2003

Modern cone scales and seeds of Pinus strobus and Sequoia sempervirens, and their fossil (Upper Miocene, c. 6 Mar) counterparts Pinus leitzii and Sequoia langsdorfii have been studied using pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), electron‐microprobe and scanning electron microscopy. Microscopic observations revealed only minor microbial activity and high‐quality structural preservation of the fossil material. The pyrolysates of both modern genera showed the presence of ligno‐cellulose characteristic of conifers. However, the abundance of (alkylated)phenols and 1,2‐benzenediols in modern S. sempervirens suggests the presence of non‐hydrolysable tannins or abundant polyphenolic moieties not previously reported in modern conifers. The marked differences between the pyrolysis products of both modern genera are suggested to be of chemosystematic significance. The fossil samples also contained ligno‐cellulose which exhibited only partial degradation, primarily of the carbohydrate constituents. Comparison between the fossil cone scale and seed pyrolysates indicated that the ligno‐cellulose complex present in the seeds is chemically more resistant than that in the cone scales. Principal component analysis (PCA) of the pyrolysis data allowed for the determination of the discriminant functions used to assess the extent of degradation and the chemosystematic differences between both genera and between cone scales and seeds. Elemental composition (C, O, S), obtained using electron‐microprobe, corroborated the pyrolysis results. Overall, the combination of chemical, microscopic and statistical methods allowed for a detailed characterization and chemosystematic interpretations of modern and fossil conifer cone scales and seeds.
Salinity tolerance in Phillyrea species
Authors: GUCCI R. , ARONNE G. , LOMBARDINI L. , TATTINI M.
Published: March 2003

The genus Phillyrea includes woody shrub species of Mediterranean maquis which can be found occasionally in saline soils or areas exposed to salt aerosols. To test salinity tolerance in Phillyrea latifolia L., plants were grown in 1–1 containers and exposed to different levels of salinity in a glasshouse over two growing seasons. Plants survived exposure to NaCl concentrations of up to 500 mM NaCl for 4 months. Analysis of the growth response to increasing salinity showed that shoot elongation was inhibited by 50% at 123 and 135 mM external NaCl after 31 and 123 d of salt treatment, respectively. Growth parameters were completely inhibited by treatment with 300 him external NaCl for 64 d. High salt tolerance in Phillyrea plants was the result of both exclusion and secretion mechanisms. Secretion of ions occurred via salt glands present mainly on the abaxial surface of the leaf. Salt glands occurred alone or in pairs and were typically formed by a highly vacuolated collecting cell, a stalk cell and a group of 10–16 secretory cells. The mean diameter of the glands was 54 μm and the average density was 6.1 mm−2 (abaxial side). Peaks of Cl, K, Ca, Na, Si, Mg, Fe and Cu were detected in salt crystals near glands by X‐ray microprobe analysis. This is the first report of salt glands in the Oleaceae family and of their role in salinity tolerance in Phillyrea species.
Identification of products formed by a fructan: fructan fructosyltransferase activity from Lolium rigidum
Authors: JOHN J. A. St , SIMS I. M. , BONNETT G. D. , SIMPSON R. J.
Published: March 2003

The products formed by a fructan: fructan fructosyltransferase (FFT) activity purified from Lolium rigidum Gaudin were identified after gas chromatography‐mass spectrometry of partially methylated alditol acetates, electrospray ionization‐mass spectrometry and reversed‐phase high‐performance liquid chromatography. The FFT activity synthesized oligofructans up to degree of polymerization (DP) 6, but did not synthesize fructans of DP > 6 even when assayed with (1,1,1)‐kestopentaose for up to 10 h. The FFT activity when assayed with 1‐kestose or 6G‐kestose synthesized fructan with fructosyl residues almost exclusively linked by β‐2,1‐glycosidic linkages. When assayed with 1‐kestose, the FFT activity synthesized tetrasaccharides and pentasaccharides with an internal glucosyl residue. The predominant tetrasaccharide was (1&6G)‐kestotetraose and the predominant pentasaccharide was (1&6G,1)‐kestopentaose. By comparison, tetrasaccharides and pentasaccharides extracted from L. rigidum also contained predominantly β‐2,1‐glycosidic linked fructans with an internal glucosyl residue. The only exception was that one of the pentasaccharides contained β‐2,1‐ and β‐2,6‐glycosidic linked fructosyl residues. This pentasaccharide was not synthesized by the FFT activity. The role of this FFT activity in formation of oligofructans in L. rigidum is discussed.