bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasound evaluation of aortic valve anatomy in the fetus
Authors: Paladini D. , Russo M. G. , Vassallo M. , Tartaglione A. , Pacileo G. , Martinelli P. , Calabrò R.
Published: March 2003

Objective

To assess the feasibility of ultrasound identification of aortic valve anatomy in the fetus, with particular emphasis on the detection of bicuspid aortic valve.

Methods

This study was a prospective analysis of 21 fetuses with prenatally diagnosed congenital left heart obstructive lesions and 45 normal fetuses undergoing routine ultrasound evaluated at a tertiary referral center. These fetuses underwent detailed echocardiography, including the study of the aortic valve on a targeted short‐axis view of the right ventricle. Necropsies or postnatal echocardiograms were available for confirmation of the diagnosis in all cases.

Results

Aortic cusps and commissures were satisfactorily visualized in 38/45 (84%) normal fetuses and in 18/21 (86%) fetuses with congenital heart disease. The aortic valve was correctly defined as bicuspid in one normal fetus and in six fetuses with congenital heart disease. In two fetuses with a positive family history, the bicuspid aortic valve was isolated. There was one incorrect diagnosis (a unicuspid unicommissural valve diagnosed prenatally as a bicuspid aortic valve in a fetus with severe aortic stenosis) and one false‐positive diagnosis in a fetus diagnosed with a coarctation and a bicuspid aortic valve late in the third trimester of pregnancy and in which both anomalies were not confirmed at neonatal echocardiography.

Conclusions

This study demonstrated that aortic valve anatomy can be satisfactorily assessed in fetuses with and without left heart obstructive lesions. We believe that a detailed search for a bicuspid aortic valve should be attempted in all patients referred for a positive family history of congenital heart disease, in general, and of left ventricle outflow tract obstruction or bicuspid aortic valve, in particular. In fact, the presence of an asymptomatic bicuspid aortic valve has been demonstrated to represent an important factor predisposing to the development of bacterial endocarditis and dissecting aortic aneurysm late in adult life. Therefore, an early detection of such an anomaly may contribute to ensure a longer symptom‐free lifespan of individuals with the most common cardiac anomaly at birth. Copyright © 2002 International Society of Ultrasound in Obstetrics and Gynecology
Axonal regeneration through acellular muscle grafts
Authors: HALL SUSAN
Published: March 2003

The management of peripheral nerve injury remains a major clinical problem. Progress in this field will almost certainly depend upon manipulating the pathophysiological processes which are triggered by traumatic injuries. One of the most important determinants of functional outcome after the reconstruction of a transected peripheral nerve is the length of the gap between proximal and distal nerve stumps. Long defects (> 2 cm) must be bridged by a suitable conduit in order to support axonal regrowth. This review examines the cellular and acellular elements which facilitate axonal regrowth and the use of acellular muscle grafts in the repair of injuries in the peripheral nervous system.
Ultrastructural localisation of nitric oxide synthase, endothelin and binding sites of lectin (from Bandeirea simplicifolia) in the rat carotid artery after balloon catheter injury
Authors: LOESCH A. , MILNER P. , ANGLIN S. C. , CROWE R. , MIAH S. , MCEWAN J. R. , BURNSTOCK G.
Published: March 2003

An immunocytochemical and cytochemical study has been made on the ultrastructural localisation of type III (endothelial) nitric oxide synthase, endothelin‐1 and the binding sites of lectin from Bandeirea simplicifolia to the endothelium surface‐associated glycoproteins in the rat left common carotid artery at 1 and 28 d after Fogarty embolectomy balloon catheter‐induced injury. Controls were carotid arteries from sham operated rats. In the controls, the immunoreactivity to nitric oxide synthase‐III and endothelin‐1 was localised in different proportions in vascular endothelial cells (36·9%±4·3 and 7·6%±2·7, respectively); immunoreactivity was confined to the cytoplasm and the membranes of intracellular organelles and structures. In contrast, staining with lectin was localised on the luminal surface of all endothelial cells. 1 d after injury, platelets were adherent to the endothelium‐denuded intima. Some of the platelets displayed immunoreactivity to nitric oxide synthase‐III and endothelin‐1 and were stained with lectin. 28 d after injury, a neointimal thickening of substantial size was present. Subpopulations of the regrown endothelial cells covering the luminal surface of the neointima showed positive immunoreactivity to nitric oxide synthase‐III and endothelin‐1 but there was a significant decrease in the proportion of nitric oxide synthase‐III‐containing endothelial cells (17·2%±1·9; P < 0·001) and a significant increase in the proportion of endothelin‐1‐containing endothelial cells (36·9%±4·7; P < 0·001) compared with the controls. Staining with lectin was associated with the cell membrane of all endothelial cells and in addition with cells located ‘deeper’ in the neointima which showed lectin‐positive plasmalemma, Golgi complex and multivesicular bodies/lysosomes. In conclusion, regenerated endothelial cells of the neointima showed reduced population (2–fold) of nitric oxide synthase‐III‐ and increased population (5–fold) endothelin‐1‐positive cells. The subendothelial location of some lectin‐stained cells after balloon catheter injury indicates the heterogeneity of the neointima and suggests that some of these cells are involved in early angiogenesis. 24 h and 28 d after injury some platelets showed positive immunoreactivity for nitric oxide synthase‐III and endothelin‐1.
An immunocytochemical study of changes in the human erythrocyte membrane skeleton produced by stretching examined by the quick‐freezing and deep‐etching method
Authors: TERADA NOBUO , FUJII YASUHISA , UEDA HIDEHO , OHNO SHINICHI
Published: March 2003

A quick‐freezing and deep‐etching method in combination with erythrocyte splitting was used to examine the cytoplasmic aspect of whole‐mount human erythrocyte membranes. Various external forces induced alterations in membrane skeletal organisation during the splitting procedure. The initial change was elongation in the peripheral part of the membrane skeleton, examined by immunostaining with a monoclonal antispectrin antibody. Under severe stretching conditions, a linear rearrangement of filamentous components was evident; these were disposed parallel to the rim of the erythrocyte, while the central part of the concavity exhibited a more compacted structure. These changes resulted in a different distribution of membrane skeletal components between central rigid and peripheral flexible areas in biconcave erythrocytes. It is suggested that the reversible membrane skeletal changes in the flexible areas which resist the external forces are important for maintaining the normal framework of biconcave human erythrocytes.
Fine structure of the cap enameloid and of the dental epithelial cells during enameloid mineralisation and early maturation stages in the tilapia, a teleost
Authors: SASAGAWA ICHIRO
Published: March 2003

Morphological features of the cap enameloid and dental epithelial cells were investigated by light and transmission electron microscopy during the various stages of enameloid mineralisation and early maturation in the tilapia. The pattern of mineralisation along collagen fibrils in the enameloid differed from that in the dentine. Many matrix vesicles were found in the predentine and in the enameloid, suggesting that they may be involved in the initial mineralisation in both regions. Most of the organic matrix disappeared from the cap enameloid during mineralisation and maturation. The disappearance of the organic matrix could be divided into 2 stages. Initially a fine network‐like matrix, which probably consisted of glycosaminoglycans and extended between collagen fibrils, began to disappear. At the same time, fine crystallites and electron‐dense, fine granular material covered the collagen fibrils as mineralisation of the enameloid began. In the second stage, the maturation of the enameloid, the collagen fibrils degenerated completely and disappeared from the cap enameloid, being replaced by large numbers of large crystals. At the mineralisation stage, the numbers of lysosomal bodies tended to increase in the inner dental epithelial (IDE) cells, which contained a well developed Golgi apparatus and rough endoplasmic reticulum (rER). At the early stage of maturation, a ruffled border was noted at the distal ends of the IDE cells, which contained many mitochondria and lysosomal bodies, but less rER. These features suggest that the cells actively absorb the organic matrix, which includes collagen fibrils, in the cap enameloid. The outer dental epithelial (ODE) cells were translucent cells that contained well developed labyrinthine canalicular spaces from the onset of the mineralisation stage to the middle stage of maturation. The IDE and ODE cells were clearly involved in the mineralisation of the cap enameloid at the mineralisation and maturation stages.
Angiogenesis at the site of neuroma formation in transected peripheral nerve
Authors: ZOCHODNE DOUGLAS W. , NGUYEN CAROLYN
Published: March 2003

Investiture of new microvessels within an injured peripheral nerve trunk may determine the success that the local environment has in promoting axonal sprouting and regeneration. We therefore examined microvessel investment of 24 h–14 d proximal nerve stump preparations in rat sciatic nerves. The stumps, later destined to form neuromas, were created by sciatic nerve transection with resection of distal branches to prevent distal reinnervation. Microvessels were studied in the proximal stump in semithin whole mount sections of nerve and by analysis of India ink perfused microvessel profiles. Quantitative image analysis was made of the luminal profiles of vessels perfused with India ink from unfixed sections of the stumps, contralateral uninjured nerves and sham‐exposed but uninjured nerves. Evidence of angiogenesis was observed in stumps 7 d after transection, indicated by a rise in the total numbers of perfused microvessels and in the numbers of 2–6 μm diameter perfused microvessels. There was a shift in the histogram of the percentage of perfused microvessels towards the 2–4 μm range and a reduction in the mean microvessel luminal area in the stumps. By 14 d, new microvessels were larger, indicated by an increase in total luminal area. New microvessels were prominent in the epineurial connective tissue or between layers of perineurial cells of former fascicles. Microvessels probably share a battery of trophic signals with other proliferating cellular elements in the milieu of the injured peripheral nerve trunk.
Studies on rat and human thymus to demonstrate immunoreactivity of calcitonin gene‐related peptide, tyrosine hydroxylase and neuropeptide Y
Authors: KRANZ ANDREA , KENDALL MARION D. , VON GAUDECKER BRITA
Published: March 2003

The peptidergic and noradrenergic innervation of rat and human thymus was investigated by immunohistochemistry at the light and electron microscopical level (avidin‐biotin‐complex, sucrose‐phosphate‐glyoxylic‐acid, and immunogold techniques). The distribution of noradrenergic neural profiles, and positive immunoreactivity for calcitonin gene‐related peptide (CGRP), tyrosine hydroxylase (TH) and neuropeptide Y (NPY) is described in female rats during ageing, and in human children. In the neonatal rat thymus, the arteries and septa are well supplied by fine varicose nerves. In older animals (2 wk–1 y) the number of septa and blood vessels increase and consequently also the innervation. No nerves were found in the cortex. Apart from the innervation of the septal areas, immunoreactivity for CGRP and TH was present in thymic cells. Except for the young rats (neonatal–14 d), all rats showed CGRP positivity in subcapsular/perivascular epithelial cells (type 1 cells). All rat thymuses also contained a few TH positive cells in the medulla, which could only be confirmed as epithelial cells (type 6 cells) in children. Type 1 cells in the human thymus were not CGRP positive, but as in the rat, there were similar TH positive cells in the medulla. It was concluded that in addition to nerves containing CGRP, noradrenaline or dopamine, epithelial cells also contain these transmitters. They could therefore act on different cells (compared with neural targets) in a paracrine manner.
Fetal villosity and microvasculature of the bovine placentome in the second half of gestation
Authors: LEISER R. , KREBS C. , KLISCH K. , EBERT B. , DANTZER V. , SCHULER G. , HOFFMANN B.
Published: March 2003

The architecture of the fetal villous tree and its vasculature in the bovine placentome were studied in the second half of gestation using both conventional histology and histology of ink‐filled blood vessels. These were compared with corrosion casts of plastic fillings of the vasculature, prepared for scanning electron microscopy. This combination of morphological methods allows perception of the villous tree throughout gestation from broad‐conical to tall‐conical form where branch ramification occurs mainly at right angles to the stem. The stem villus typically contains a single central artery and several peripheral veins arranged in parallel. The proximal branches to the stem, the intermediate villi, contain a central arteriole and accompanying venules. The distal branches, the terminal villi, enclose capillary convolutions which consist of an afferent arterial capillary limb, capillary loops and efferent venous capillary limbs. Vascular interconnections exist within the terminal villi, as capillaries or venules between the capillary convolutions, serially bridging them in up to 5 places, and as capillary anastomoses between the capillary loops. Coiling and sinusoidal dilatations of these loops develop near the end of gestation. The intraplacentomal rearrangement of villous trees with progressive gestation and their morphological vascular adaptations are discussed in relation to placental function, including the ever increasing need for transplacental substance exchange. This adaptation allows the blood to traverse the shortest possible arterioarteriolar route to the periphery of the trees where exchange takes place. The need for an increasing blood flow stimulates capillary growth and at the same time optimises the blood flow reaching the placental barrier represented by the vessel cast surface. The capillaries also carry the blood back into the very voluminous system of venules and veins where back diffusion may occur. The total volume of terminal villi of bovine placentome, the ‘working part’ of villous trees, hence distinctly increases with respect to the stem and intermediate villi, the ‘supplying part’ of the villous tree. In morphological terms the efficiency of the bovine transplacental diffusional exchange is higher than in the closely related ‘co‐ruminants’ sheep and goats and distinctly higher when compared with the human placenta.
Ultrastructural and cytochemical evaluation of sepsis‐induced changes in the rat pulmonary intravascular mononuclear phagocytes
Authors: SINGH BALJIT , DOANE KATHLEEN J. , NIEHAUS GARY D.
Published: March 2003

Sepsis stimulates an increase in the number and activity of mononuclear phagocytes in systemic host‐defence organs. The present study was conducted to define the ultrastructural and cytochemical characteristics of the mononuclear phagocytes that sequester in the lung microvasculature of septic rats. Fourteen rats were challenged with a single intraperitoneal injection of saline (0.5 ml/100 g), E. coli (2×107/100 g) or glucan (4 mg/100 g), and euthanased 2, 4, or 7 d later. The lungs were inflation fixed and processed for transmission electron microscopy. Cellular morphology was used to identify the intravascular mononuclear phagocytes and acid phosphatase (AcPase) expression was monitored as an index of cellular differentiation and activation. Control rats contained a limited number of monocytes in the pulmonary vasculature. In contrast, large numbers of activated mononuclear phagocytes were seen in the microvasculature within 48 h of treatment with either microbial product. The recruited pulmonary intravascular mononuclear phagocytes (PIMP) exhibited AcPase‐reactive Golgi complexes, accumulation of secretory vesicles and other features of cell activation consistent with enhanced biosynthetic activity. Subsequent electron microscopy, conducted 4 and 7 d posttreatment, suggested that a progressive decline in the number and activity of PIMPs then occurred. In order to quantify the sepsis‐induced accumulation of AcPase‐positive PIMP, the experimental challenges were repeated in 11 rats and, 48 h later, tissue samples were evaluated by light microscopy for tartrate‐insensitive acid phosphatase. Control rats exhibited 0.148±0.107 AcPase‐positive PIMP/alveoli. E. coli and glucan challenged animals exhibited significant (P<0.01) increases in AcPase‐positive mononuclear phagocytes, with 0.782±0.073 and 0.636±0.170 PIMP/alveoli respectively. The results demonstrate that focal sepsis stimulates a significant, but transient, recruitment of activated mononuclear phagocytes into the rat pulmonary microvasculature.
An unusual structure of venules in tonsils of the soft palate of young pigs
Authors: BELZ GABRIELLE T.
Published: March 2003

In tonsils of the soft palate of pigs high endothelial venules (HEV) occur throughout the parafollicular region. In some regions of the venules the endothelial lining is uniformly high; in other areas, mainly the nuclear region of the endothelial cell protrudes into the lumen and the cytoplasmic region is attenuated. In this portion of the venule endothelial cells may traverse the lumen of the vessel to form intravascular bridging processes. The endothelial cells are characterised by pinocytotic vesicles, many surface microvilli, cytoplasmic processes and local cell‐cell contacts with adjacent endothelial cells. These specialised HEV may play a role in the unusual pattern of lymphocytes from tonsillar tissue into blood. In the tonsils of the soft palate of pigs, HEV may mediate both lymphocyte migration to and from the lymphoid tissue. Further investigation is required to determine the importance of these 2 migration pathways.
Comparative skeletal muscle fibre morphometry among wild birds with different locomotor behaviour
Authors: TORRELLA J. R. , FOUCES V. , PALOMEQUE J. , VISCOR G.
Published: March 2003

Six muscles of the mallard duck (Anas platyrhynchos), the common coot (Fulica atra) and the yellow‐legged gull (Larus cachinnans) were analysed morphometrically, with special emphasis on their functional implications and physiological needs. Oxidative fibres always had significantly smaller size than anaerobic fibres, although no differences in the number of capillaries per fibre were found. This resulted in greater capillary counts per unit of fibre area and perimeter in oxidative than anaerobic fibres, which indicates that the greater demand for oxygen supply may be achieved by decreasing the size of the muscle fibre rather than by increasing the number of associated capillaries. Fast oxidative fibres of the pectoralis and the triceps of the gull had greater sizes than the fast oxidative fibres of the mallard and the coot, which correlates with the difference in energetic demands between flapping and gliding flight. Greater fibre cross‐sectional areas and perimeters seem suited to afford the long‐lasting activity with low metabolic demands required during gliding. By contrast, mallards and coots attain a high oxidative metabolism, during sustained flapping flight, by reducing fibre size at the expense of a diminished ability for force generation. Between‐species comparisons of the hindlimb muscles only yielded differences for the anaerobic fibres of the gastrocnemius, as an important adaptive response to force generation during burst locomotion. The need to manage sustained swimming abilities effectively may result in similar FOG fibre morphometry of the hindlimb muscles studied, indicating that a compromise between the oxygen flux to the muscle cell and the development of power is highly optimised in oxidative fibres of the bird species studied.
Immunofluorescent localisation of tumour necrosis factor‐α receptors on the popliteal lymph node and the surrounding adipose tissue following a simulated immune challenge
Authors: MacQUEEN HILARY A. , POND CAROLINE M.
Published: March 2003

We used immunohistochemical techniques to demonstrate the distribution of receptors for the cytokine tumour necrosis factor‐α on the popliteal lymph node and the adipose tissue surrounding it for 5 d following a simulated immune challenge to one hind leg in the rat. We found different patterns of expression of receptors on adipocytes surrounding a lymph node to a distance of about 1 mm, and on those more remote from the node. Sites recognised by an antibody to type I tumour necrosis factor receptors appeared on the challenged node and the adipocytes surrounding it within 30 min of an injection of bacterial lipopolysaccharide, but appeared on adipocytes surrounding the unchallenged popliteal node only 24 h later. Adipocytes distant from the node, both within the same depot and in the contralateral depot, showed no response. Sites recognised by an antibody to type II tumour necrosis factor receptors were present at all times on lymph nodes and the adipocytes close to them, but appeared on more distant adipocytes only 24 h after immune challenge, in both challenged and unchallenged legs. These data support the proposal, based on in vitro studies, that the adipose tissue surrounding major lymph nodes is specialised to respond to cytokines derived from lymphoid cells, and participates in the immune responses of the adjacent node.
Collagen fibril arrangement and size distribution in monkey oral mucosa
Authors: OTTANI V. , FRANCHI M. , DE PASQUALE V. , LEONARDI L. , MOROCUTTI M. , RUGGERI A.
Published: March 2003

Collagen fibre organisation and fibril size were studied in the buccal gingival and hard palate mucosa of Macacus rhesus monkey. Light and electron microscopy analysis showed connective papillae exhibiting a similar inner structure in the different areas examined, but varying in distribution, shape and size. Moving from the deep to surface layers of the buccal gingival mucosa (free and attached portions), large collagen fibril bundles became smaller and progressively more wavy with decreasing collagen fibril diameter. This gradual diameter decrease did not occur in the hard palate mucosa (free portion, rugae and interrugal regions) where the fibril diameter remained constant. A link between collagen fibril diameter and mechanical function is discussed.
The effects of age on the overall population and on subpopulations of myenteric neurons in the rat small intestine
Authors: JOHNSON R. J. R. , SCHEMANN M. , SANTER R. M. , COWEN T.
Published: March 2003

Previous studies on ageing animal and human subjects have demonstrated a significant overall decline in neuronal numbers in the myenteric plexus of the enteric nervous system (ENS). Our study aimed to confirm this observation by counting myenteric neurons stained with the panneuronal markers PGP 9.5 and NADH‐diaphorase. We also wished to examine the possibility that particular subpopulations of neurons are vulnerable. Therefore, we have immunostained and counted a number of nerve cell groups within the myenteric plexus of old and young Sprague Dawley rats using markers which reflect some of the neuronal phenotypes present, including ChAT and VIP. The number of neurons demonstrating NADH‐diaphorase activity was significantly reduced (P<0.05) by approximately 15% in old rats. However, the number of neurons stained for PGP 9.5 immunohistochemistry was not reduced and demonstrated larger numbers of neurons than the NADH‐diaphorase method. None of the other neuronal markers studied showed any significant reductions with age. In contrast to previous work, this study has gathered little evidence for extensive cell loss in the myenteric plexus of the aged rat, either in overall populations, or in any of the principal functional groups of neurons.
Restricted expression of the gap junctional protein connexin 43 in the arterial system of the rat
Authors: HONG TAO , HILL CARYL E.
Published: March 2003

Connexin 43 (Cx43) has been reported to be expressed in vascular smooth muscle cells and endothelial cells. Evidence for possible variations in Cx43 distribution within different parts of the vascular system is limited. We have therefore investigated the expression of Cx43 in the endothelia and media of 11 vessels of different size and function in the rat, using immunofluorescence and confocal laser scanning microscopy. The results showed that punctate Cx43 staining was abundant in the endothelia and media of all of the 5 elastic arteries examined. In the media, the amount of Cx43 staining decreased as the size of the elastic arteries became smaller. In the 6 muscular arteries examined, 2 different patterns of Cx43 staining were observed. In the first type, Cx43 expression was high in the endothelium but virtually absent from the media. Mesenteric resistance, hepatic and tail arteries were examples. In the second type, Cx43 staining was absent from both the media and the endothelia. The coronary, basilar, and middle cerebral arteries showed this appearance. The results suggest that expression of Cx43 is largely restricted to elastic arteries in the arterial system of the rat. The lack of immunodetectable Cx43 from the media of all muscular arteries examined, and from the endothelia of some of these arteries, raises the possibility of significant differences in the form of expression of Cx43 in these vessels or the presence of other connexins.
Morphogenesis of Doublefoot (Dbf), a mouse mutant with polydactyly and craniofacial defects
Authors: HAYES CHRISTOPHER , LYON MARY F. , MORRISS‐KAY GILLIAN M.
Published: March 2003

We report the morphogenesis of a new mouse mutant, Doublefoot (Dbf). The major phenotypic features involve the limb and craniofacial regions. There is polydactyly of all 4 limbs, with typically 6–8 digits per limb. All of the digits are triphalangeal; some show bifurcations and some are not attached to the carpus/tarsus. The carpus and tarsus are broader than normal, and their elements are partially fused. There are also tibial defects. Mutant embryos show a diencephalic bulge on d 10.0, with older animals exhibiting broadened and bulbous skulls sometimes with an additional midline skeletal element, shortened snouts and bulging eyes. Homozygotes, which do not survive beyond d 15, show midline facial clefting. In this study of the embryonic and fetal development of Dbf animals, we focus on the morphogenesis of the limbs and head, and discuss the possible molecular developmental mechanisms.
Fibrocartilage in tendons and ligaments — an adaptation to compressive load
Authors: BENJAMIN M. , RALPHS J. R.
Published: March 2003

Where tendons and ligaments are subject to compression, they are frequently fibrocartilaginous. This occurs at 2 principal sites: where tendons (and sometimes ligaments) wrap around bony or fibrous pulleys, and in the region where they attach to bone, i.e. at their entheses. Wrap‐around tendons are most characteristic of the limbs and are commonly wider at their point of bony contact so that the pressure is reduced. The most fibrocartilaginous tendons are heavily loaded and permanently bent around their pulleys. There is often pronounced interweaving of collagen fibres that prevents the tendons from splaying apart under compression. The fibrocartilage can be located within fascicles, or in endo‐ or epitenon (where it may protect blood vessels from compression or allow fascicles to slide). Fibrocartilage cells are commonly packed with intermediate filaments which could be involved in transducing mechanical load. The ECM often contains aggrecan which allows the tendon to imbibe water and withstand compression. Type II collagen may also be present, particularly in tendons that are heavily loaded. Fibrocartilage is a dynamic tissue that disappears when the tendons are rerouted surgically and can be maintained in vitro when discs of tendon are compressed. Finite element analyses provide a good correlation between its distribution and levels of compressive stress, but at some locations fibrocartilage is a sign of pathology. Enthesis fibrocartilage is most typical of tendons or ligaments that attach to the epiphyses of long bones where it may also be accompanied by sesamoid and periosteal fibrocartilages. It is characteristic of sites where the angle of attachment changes throughout the range of joint movement and it reduces wear and tear by dissipating stress concentration at the bony interface. There is a good correlation between the distribution of fibrocartilage within an enthesis and the levels of compressive stress. The complex interlocking between calcified fibrocartilage and bone contributes to the mechanical strength of the enthesis and cartilage‐like molecules (e.g. aggrecan and type II collagen) in the ECM contribute to its ability to withstand compression. Pathological changes are common and are known as enthesopathies.
Morphology of the cervical vertebrae in the fetal‐neonatal human skeleton
Authors: CASTELLANA C. , KÓSA F.
Published: March 2003

The gross anatomical features of human cervical vertebrae during the fetal‐neonatal period were investigated in order to develop morphological standards for the individual ossification centres for use in forensic and anthropological osteology. It was found that the morphology of the cervical vertebral arches and the centra cannot be used for the determination of fetal age although the dens of the axis displays some developmental differences which may be useful for the determination of fetal maturity.
Shape differences in the cervical and upper thoracic vertebrae in rats (Rattus norvegicus) and bats (Pteropus poiocephalus): can we see shape patterns derived from position in column and species membership?
Authors: JOHNSON D. R. , McANDREW T. J. , OGUZ ÖZKAN
Published: March 2003

The shapes of cervical (C1–C7) and upper thoracic (T1, T2) vertebrae from the rat and the grey‐headed flying fox have been analysed by Fourier analysis to investigate the types of variation present and to try to isolate bones according to position along the vertebral column and species. It was found that the T2 vertebrae of the rat are very different from all others in the study, that C2 and C6 vertebrae are very similar and that the remaining vertebrae split according to species.
Increase in liver pigmentation during natural hibernation in some amphibians
Authors: BARNI SERGIO , BERTONE VITTORIO , CROCE ANNA CLETA , BOTTIROLI GIOVANNI , BERNINI FRANCO , GERZELI GIUSEPPE
Published: March 2003

The amount/distribution of liver melanin in 3 amphibian species (Rana esculenta, Triturus a. apuanus, Triturus carnifex) was studied during 2 periods of the annual cycle (summer activity–winter hibernation) by light and electron microscopy, image analysis and microspectrofluorometry. The increase in liver pigmentation (melanin content) during winter appeared to be correlated with morphological and functional modifications in the hepatocytes, which at this period were characterised by a decrease in metabolic activity. These findings were interpreted according to the functional role (e.g. phagocytosis, cytotoxic substance inactivation) played by the pigment cell component in the general physiology of the heterothermic vertebrate liver and, in particular, in relation to a compensatory engagement of these cells against hepatocellular hypoactivity during the winter period.
Electron‐immunocytochemical studies of perivascular nerves of mesenteric and renal arteries of golden hamsters during and after arousal from hibernation
Authors: SAITONGDEE PORNCHARN , MILNER PAMELA , LOESCH ANDRZEJ , KNIGHT GILLIAN , BURNSTOCK GEOFFREY
Published: March 2003

Electron immunocytochemistry was used to examine perivascular nerves of hamster mesenteric and renal arteries during hibernation and 2 h after arousal from hibernation. Vessels from cold‐exposed but nonhibernating, and normothermic control hamsters were also examined. During hibernation the percentage of axon profiles in mesenteric and renal arteries that were immunopositive for markers of sympathetic nerves, tyrosine hydroxylase (TH) and neuropeptide Y (NPY), were increased 2–3 fold compared with normothermic and cold control animals. This increase was reduced markedly only 2 h after arousal from hibernation. The small percentage of nitric oxide synthase‐1‐positive axon profiles found in mesenteric (but not renal) arteries was also increased during hibernation and returned towards control values after arousal. In contrast, the percentage of perivascular axons immunostaining for vasoactive intestinal polypeptide (VIP), a marker for parasympathetic nerves, was reduced in mesenteric arteries during hibernation. There was no labelling of perivascular nerves for substance P in either mesenteric or renal arteries. It is suggested that the increase in percentage of TH‐ and NPY‐immunostained perivascular nerves may account for the increased vasoconstriction associated with high vascular resistance that is known to occur during hibernation. The reduction in the percentage of axons positive for VIP in hibernating animals would contribute to this mechanism since this neuropeptide is a vasodilator.
Synaptic organisation of the basal ganglia
Authors: BOLAM J. P. , HANLEY J. J. , BOOTH P. A. C. , BEVAN M. D.
Published: March 2003

The basal ganglia are a group of subcortical nuclei involved in a variety of processes including motor, cognitive and mnemonic functions. One of their major roles is to integrate sensorimotor, associative and limbic information in the production of context‐dependent behaviours. These roles are exemplified by the clinical manifestations of neurological disorders of the basal ganglia. Recent advances in many fields, including pharmacology, anatomy, physiology and pathophysiology have provided converging data that have led to unifying hypotheses concerning the functional organisation of the basal ganglia in health and disease. The major input to the basal ganglia is derived from the cerebral cortex. Virtually the whole of the cortical mantle projects in a topographic manner onto the striatum, this cortical information is ‘processed’ within the striatum and passed via the so‐called direct and indirect pathways to the output nuclei of the basal ganglia, the internal segment of the globus pallidus and the substantia nigra pars reticulata. The basal ganglia influence behaviour by the projections of these output nuclei to the thalamus and thence back to the cortex, or to subcortical ‘premotor’ regions. Recent studies have demonstrated that the organisation of these pathways is more complex than previously suggested. Thus the cortical input to the basal ganglia, in addition to innervating the spiny projection neurons, also innervates GABA interneurons, which in turn provide a feed‐forward inhibition of the spiny output neurons. Individual neurons of the globus pallidus innervate basal ganglia output nuclei as well as the subthalamic nucleus and substantia nigra pars compacta. About one quarter of them also innervate the striatum and are in a position to control the output of the striatum powerfully as they preferentially contact GABA interneurons. Neurons of the pallidal complex also provide an anatomical substrate, within the basal ganglia, for the synaptic integration of functionally diverse information derived from the cortex. It is concluded that the essential concept of the direct and indirect pathways of information flow through the basal ganglia remains intact but that the role of the indirect pathway is more complex than previously suggested and that neurons of the globus pallidus are in a position to control the activity of virtually the whole of the basal ganglia.
Glucocorticoids and the ageing hippocampus
Authors: HIBBERD CARINA , YAU JOYCE L. W. , SECKL JONATHAN R.
Published: March 2003

Approximately 30% of human and mammalian populations develop cognitive impairments with ageing. Many of these impairments have been linked to dysfunction of the hippocampus, a well studied area of the medial‐temporal lobe, which is involved in episodic memory and control of the hypothalamo‐pituitary‐adrenal stress axis and, thus, of glucocorticoid secretion. This paper reviews the growing body of studies which explore a possible relationship between lifetime exposure to glucocorticoids and hippocampal impairment. There is now strong evidence which associates hypercortisolemia in aged men with later cognitive dysfunction and this complements a wealth of rodent and other human data. We conclude with a discussion of possible pharmacological and behavioural interventions.
Fibrocartilage in the transverse ligament of the human acetabulum
Authors: MILZ STEFAN , VALASSIS GEORGIOS , BÜTTNER ANDREAS , MAIER MARKUS , PUTZ REINHARD , RALPHS JAMES R. , BENJAMIN MICHAEL
Published: March 2003

Biomechanical experiments on isolated hip joints have suggested that the transverse ligament acts as a bridle for the lunate articular surface of the acetabulum during load bearing, but there are inherent limitations in such studies because the specimens are fixed artificially to testing devices and there are no modifying influences of muscle pull. Further evidence is thus needed to substantiate the theory. Here we argue that if the horns of the lunate surface are forced apart under load, the ligament would straighten and become compressed against the femoral head. It would thus be expected to share some of the features of tendons and ligaments that wrap around bony pulleys and yet previous work has suggested that the transverse ligament is purely fibrous. Transverse ligaments were removed from 8 cadavers (aged 17–39 y) and fixed in 90% methanol. Cryosections were immunolabelled with antibodies against collagens (types I, II, III, VI), glycosaminoglycans (chondroitins 4 and 6 sulphate, dermatan sulphate, keratan sulphate) and proteoglycans (aggrecan, link protein, versican, tenascin). A small sesamoid fibrocartilage was consistently present in the centre of each transverse ligament, near its inner surface at the site where it faced the femoral head. Additionally, a more prominent enthesis fibrocartilage was found at both bony attachments. All fibrocartilage regions, in at least some specimens, labelled for type II collagen, chondroitin 6 sulphate, aggrecan and link protein, molecules more typically associated with articular cartilage. The results suggest that the ligament should be classed as containing a ‘moderately cartilaginous’ sesamoid fibrocartilage, adapted to withstanding compression. This supports the inferences that can be drawn from previous biomechanical studies. We cannot give any quantitative estimate of the levels of compression experienced. All that can be said is that the ligament occupies an intermediate position in the spectrum of fibrocartilaginous tissues. It is more cartilaginous than some wrap‐around tendons at the wrist, but less cartilaginous than certain other wrap‐around ligaments, e.g. the transverse ligament of the atlas.
Specialised cell types in the chorioallantoic membrane express carbonic anhydrase during chick embryogenesis
Authors: GABRIELLI M. GABRIELLA , MATERAZZI GIOVANNI , COX JOHN V. , MENGHI GIOVANNA
Published: March 2003

The expression of carbonic anhydrase in the chorioallantoic membrane (CAM) of the chick embryo was investigated by means of the histochemical localisation of the enzyme catalytic sites and the immunohistochemical identification of its isoenzymatic forms. The results show that carbonic anhydrase is developmentally expressed in a subset of cells both in the ectodermal and the endodermal epithelium. The distribution patterns from both methodological approaches indicated that carbonic anhydrase is a marker of the villus cavity cells and the mitochondria‐rich cells in the ectodermal and the endodermal epithelium, respectively. Such a cell‐specific pattern of the enzyme expression provides a further contribution to characterising the heterogeneous cell population of the chick CAM and supports specific functional involvement for the distinct cell types in CAM‐mediated processes, such as calcium transport, maintenance of acid‐base balance and water and electrolyte reabsorption, during chick embryogenesis.
Gluteus minimus: observations on its insertion
Authors: WALTERS JOHAN , SOLOMONS MICHAEL , DAVIES JOHN
Published: March 2003

In 17 adult and 3 full term fetuses the hip joints were dissected to expose the insertion of gluteus minimus. An attachment of the deep surface of the tendon as it passes over the hip joint capsule was found in every case. Histological examination of this insertion confirmed the presence of short intramuscular tendons firmly anchoring the tendon to the capsule. It is suggested that this attachment retracts the capsule during hip joint motion, thereby preventing capsular entrapment.
Muscle fibre types in the suprahyoid muscles of the rat
Authors: COBOS A. R. , SEGADE L. A. G. , FUENTES I.
Published: March 2003

Five muscle fibre types (I, IIc, IIa, IIx and IIb) were found in the suprahyoid muscles (mylohyoid, geniohyoid, and the anterior and posterior bellies of the digastric) of the rat using immuno and enzyme histochemical techniques. More than 90% of fibres in the muscles examined were fast contracting fibres (types IIa, IIx and IIb). The geniohyoid and the anterior belly of the digastric had the greatest number of IIb fibres, whilst the mylohyoid was almost exclusively formed by aerobic fibres. The posterior belly of the digastric contained a greater percentage of aerobic fibres (83.4%) than the anterior belly (67.8%). With the exception of the geniohyoid, the percentage of type I and IIc fibres, which have slow myosin heavy chain (MHCβ), was relatively high and greater than has been previously reported in the jaw‐closing muscles of the rat, such as the superficial masseter. The geniohyoid and mylohyoid exhibited a mosaic fibre type distribution, without any apparent regionalisation, although in the later MHCβ‐containing fibres (types I and IIc) were primarily located in the rostral 2/3 region. In contrast, the anterior and posterior bellies of the digastric revealed a clear regionalisation. In the anterior belly of the digastric 2 regions were observed: both a central region, which was almost exclusively formed by aerobic fibres and where all of the type I and IIc fibres were located, and a peripheral region, where type IIb fibres predominated. The posterior belly of the digastric showed a deep aerobic region which was greater in size and where type I and IIc fibres were confined, and a superficial region, where primarily type IIx and IIb fibres were observed.
The thymus of the hairless rhino‐j (hr/hr‐j) mice
Authors: SAN JOSE I. , GARCÍA‐SUÁREZ O. , HANNESTAD J. , CABO R. , GAUNA L. , REPRESA J. , VEGA J. A.
Published: March 2003

The hairless (hr) gene is expressed in a large number of tissues, primarily the skin, and a mutation in the hr gene is responsible for the typical cutaneous phenotype of hairless mice. Mutant hr mouse strains show immune defects involving especially T cells and macrophages, as well as an age‐related immunodeficiency and an accelerated atrophy of the thymus. These data suggest that the hr mutation causes a defect of this organ, although hr transcripts have not been detected in fetal or adult mice thymus. The present study analyses the thymus of young (3 mo) and adult (9 mo) homozygous hr‐rh‐j mice (a strain of hairless mice) by means of structural techniques and immunohistochemistry to selectively identify thymic epithelial cells, dendritic cells, and macrophages. There were structural alterations in the thymus of both young and adult rh‐rh‐j mice, which were more severe in older animals. These alterations consisted of relative cortical atrophy, enlargement of blood vessels, proliferation of perivascular connective tissue, and the appearance of cysts. hr‐rh‐j mice also showed a decrease in the number of epithelial and dendritic cells, and macrophages. Taken together, present results strongly suggest degeneration and accelerated age‐dependent regression of the thymus in hr‐rh‐j mice, which could explain at least in part the immune defects reported in hairless mouse strains.
Origin and course of the coronary arteries in normal mice and in iv/iv mice
Authors: ICARDO JOSÉ M. , COLVEE ELVIRA
Published: March 2003

This paper reports on the origin and distribution of the coronary arteries in normal mice and in mice of the iv/iv strain, which show situs inversus and heterotaxia. The coronary arteries were studied by direct observation of the aortic sinuses with the scanning electron microscope, and by examination of vascular corrosion casts. In the normal mouse, the left and right coronaries (LC, RC) arise from the respective Valsalva sinus and course along the ventricular borders to reach the heart apex. Along this course the coronary arteries give off small branches at perpendicular or acute angles to supply the ventricles. The ventricular septum is supplied by the septal artery, which arises as a main branch from the right coronary. Conus arteries arise from the main coronary trunks, from the septal artery and/or directly from the Valsalva sinus. The vascular casts demonstrate the presence of intercoronary anastomoses. The origin of the coronary arteries was found to be abnormal in 84% of the iv/iv mice. These anomalies included double origin, high take‐off, slit‐like openings and the presence of a single coronary orifice. These anomalies occurred singly or in any combination, and were independent of heart situs. The septal artery originated from RC in most cases of situs solitus but originated predominantly from LC in situs inversus hearts. Except for this anomalous origin no statistical correlation was found between the coronary anomalies and heart situs or a particular mode of heterotaxia. The coronary anomalies observed in the iv/iv mice are similar to those found in human hearts. Most coronary anomalies appear to be due to defective connections between the aortic root and the developing coronaries. iv/iv mice may therefore constitute a good model to study the development of similar anomalies in the human heart.