bluuebunny/crossref_metadata_2025 huggingface dataset:
Anastomosis at the level of the elbow joint connecting the deep, or normal, brachial artery with major arterial variations of the upper limb
Authors: RODRÍGUEZ‐NIEDENFÜHR M. , SAÑUDO J. R. , VÁZQUEZ T. , NEARN L. , LOGAN B. , PARKIN I.
Published: March 2003

Major variations of the principal arteries of the upper limb have long received the attention of anatomists. These variations can be summarised as the presence of 2 main arteries traversing the cubital fossa, a deep (or normal) brachial artery in coexistence with a superficial brachial, radial or ulnar artery. Anastomosis between these arterial trunks at elbow level has been reported in 1–6% of cases as an incidental finding in studies on the major arterial variations of the upper limb (Quain, 1844; Müller, 1903; Poynter, 1922; Adachi, 1928; McCormack et al. 1953; Wankoff, 1962; Rodríguez‐Baeza et al. 1995). Only a single report (Ljubomudroff, 1927) has dealt specifically with the anastomosis.

The anatomical pattern of the anastomosis has been classified into 2 or 3 types depending on different morphological details. Three types have been described, taking into account its length, calibre and form (Quain, 1844) or the positions of the origin and number of recurrent radial arteries (Ljubomudroff, 1927). Two types have been described on the basis of whether the anastomosis coursed anterior or posterior to the bicipital tendon (McCormack et al. 1953). The aim of this study was to revisit these specific morphological details in a statistically reliable sample in order to catalogue the variations of the anastomosis and to provide an embryological explanation.
The study of morphological variation in the hominid fossil record: biology, landmarks and geometry
Authors: O'HIGGINS PAUL
Published: March 2003

This review considers some recent advances in shape analysis based on landmark data, and focuses on the application of these methods to the study of skeletal evolution in primates. These advances have provoked some controversy. The major aims of this review are to put these debates in context and to provide an overview for the nonmathematician. The purpose of morphometric studies is considered, together with issues relating to the nature, significance and identification of landmarks before turning to a review of available technologies for the analysis of morphological variation. These are considered in terms of underlying models and assumptions in order to clarify when each is appropriate. To illustrate the application of these methods, 3 example studies are presented. The first examines differences amongst ancient and modern adult human crania using 2‐dimensional data. The second illustrates the extension of these methods into 3 dimensions in a study of facial growth in monkeys. The third presents an application to the analysis of the form of the hominoid talus. The review ends with an account of available software resources for shape analysis.
Variation in shape of the lingula in the adult human mandible
Authors: TULI A. , CHOUDHRY R. , CHOUDHRY S. , RAHEJA S. , AGARWAL S.
Published: March 2003

The lingulae of both sides of 165 dry adult human mandibles, 131 males and 34 females of Indian origin, were classified by their shape into 4 types: 1, triangular; 2, truncated; 3, nodular; and 4, assimilated. Triangular lingulae were found in 226 (68.5%) sides, truncated in 52 (15.8%), nodular in 36 (10.9%) and assimilated in 16 (4.8%) sides. Triangular lingulae were found bilaterally in 110, truncated in 23, nodular in 17 and assimilated in 7 mandibles. Of the remaining 8 mandibles with different appearances on the 2 sides, 6 had a combination of triangular and truncated and 2 had nodular and assimilated. The incidence of triangular and assimilated types in the male and female mandibles are almost equal. In the truncated type it was double in the male mandibles while the nodular type was a little less than double in the female mandibles.
Curving and looping of the internal carotid artery in relation to the pharynx: frequency, embryology and clinical implications
Authors: PAULSEN FRIEDRICH , TILLMANN BERNHARD , CHRISTOFIDES CHRISTOS , RICHTER WALBURGA , KOEBKE JÜRGEN
Published: March 2003

Variations of the course of the internal carotid artery in the parapharyngeal space and their frequency were studied in order to determine possible risks for acute haemorrhage during pharyngeal surgery and traumatic events, as well as their possible relevance to cerebrovascular disease. The course of the internal carotid artery showed no curvature in 191 cases, but in 74 cases it had a medial, lateral or ventrocaudal curve, and 17 preparations showed kinking (12) or coiling (5) out of a total of 265 dissected carotid sheaths and 17 corrosion vascular casts. In 6 cases of kinking and 2 of coiling, the internal carotid artery was located in direct contact with the tonsillar fossa. No significant sex differences were found. Variations of the internal carotid artery leading to direct contact with the pharyngeal wall are likely to be of great clinical relevance in view of the large number of routine procedures performed. Whereas coiling is ascribed to embryological causes, curving is related to ageing and kinking is thought to be exacerbated by arteriosclerosis or fibromuscular dysplasia with advancing age and may therefore be of significance in relation to the occurrence of cerebrovascular symptoms.
Visualisation of three‐dimensional microcracks in compact bone
Authors: O'BRIEN F. J. , TAYLOR D. , DICKSON G. R. , LEE T. C.
Published: March 2003

Microdamage in bone contributes to the loss of bone quality in osteoporosis and is thought to play a major role in both fragility and stress fractures (Schaffler et al. 1995). In this study, in vivo microcracks in human ribs were bulk‐stained in basic fuchsin and viewed in longitudinal section and in 3 dimensions using 2 different computer‐based methods of reconstruction: (1) serial sectioning of methylmethacrylate embedded sections using a sledge macrotome and identification of microcracks using UV epifluorescence followed by computerised reconstruction of microcracks using software and (2) laser scanning confocal microscopy of thick sections followed by reconstruction of microcracks into a 3‐D image. The size and shape of microcracks were found to be similar using both techniques. Both techniques of reconstruction showed microcracks to be approximately elliptical in shape. From the serial sectioning reconstructions (n = 9), microcracks were found to have a mean length of 404±145 μm (mean±S.D.) (in the longitudinal direction) and mean width of 97±38 μm (in the transverse direction). Using epifluorescence microscopy, 92 microcracks were identified; mean microcrack length was 349±100 μm in the longitudinal direction. This was consistent with other results (Burr & Martin, 1993) and with the theoretical prediction of an elliptical crack shape with aspect ratio (longitudinal∶transverse) of 5∶1 deduced from analysis of random 2‐D sections (Taylor & Lee, 1998). The results obtained provide new data on the nature of microcracks in bone and the method has the potential to become a useful tool in the calculation of stress intensity values which indicate the probability of an individual microcrack propagating to cause a stress or fragility fracture.
Morphology of human intracardiac nerves: an electron microscope study
Authors: PAUZIENE NERINGA , PAUZA DAINIUS H. , STROPUS RIMVYDAS
Published: March 2003

Since many human heart diseases involve both the intrinsic cardiac neurons and nerves, their detailed normal ultrastructure was examined in material from autopsy cases without cardiac complications obtained no more than 8 h after death. Many intracardiac nerves were covered by epineurium, the thickness of which was related to nerve diameter. The perineurial sheath varied from nerve to nerve and, depending on nerve diameter, contained up to 12 layers of perineurial cells. The sheaths of the intracardiac nerves therefore become progressively attenuated during their course in the heart. The intraneural capillaries of the human heart differ from those in animals in possessing an increased number of endothelial cells. A proportion of the intraneural capillaries were fenestrated. The number of unmyelinated axons within unmyelinated nerve fibres was related to nerve diameter, thin cardiac nerves possessing fewer axons. The most distinctive feature was the presence of stacks of laminated Schwann cell processes unassociated with axons that were more frequent in older subjects. Most unmyelinated and myelinated nerve fibres showed normal ultrastructure, although a number of profiles displayed a variety of different axoplasmic contents. Collectively, the data provide baseline information on the normal structure of intracardiac nerves in healthy humans which may be useful for assessing the degree of nerve damage both in autonomic and sensory neuropathies in the human heart.
Exercise, oxidative stress and ageing
Authors: McARDLE ANNE , JACKSON MALCOLM J.
Published: March 2003

Skeletal muscle has the unique ability to increase the rate of oxygen usage during contraction. This has led several workers to suggest that by‐products of this increased oxygen consumption, oxygen‐derived free radicals, may be primarily responsible for exercise‐induced damage to skeletal muscle. However, because of this rapidly changing redox state, skeletal muscle has developed a number of different endogenous mechanisms which adapt rapidly following a period of exercise. These include numerous structural and biochemical changes such as increased muscle activity of antioxidant enzymes and content of stress or heat shock proteins (HSPs). This adaptation is associated with protection against the potentially damaging effects of a second period of exercise. In addition, we have recently demonstrated a significant increase in free radical production during a period of nondamaging exercise, which is rapidly followed by a significant increase in the expression of antioxidant enzymes and HSPs, suggesting that a change in redox state of the muscle may act as signal for adaptation.
Ultrastructural characteristics and lectin‐binding properties of M cells in the follicle‐associated epithelium of chicken caecal tonsils
Authors: KITAGAWA HIROSHI , SHIRAISHI SHIGEKAZU , IMAGAWA TOMOHIRO , UEHARA MASATO
Published: March 2003

To clarify the nature of M cells, the detailed ultrastructural characteristics and lectin‐binding properties of M cells were investigated in follicle‐associated epithelium (FAE) of chicken caecal tonsils. M cells presented various outlines from columnar to dome shaped. Their polymorphism was dependent on the number of harboured intraepithelial migrating cells. The lighter and larger nuclei of M cells were situated at more apical levels in the epithelial lining compared with those of neighbouring microvillous epithelial cells. The microvilli, which were significantly shorter and thicker than those of adjacent microvillous epithelial cells, were sparsely distributed or completely absent on the apical surfaces of M cells. In general, the apical cytoplasm of M cells without microvilli protruded slightly into the intestinal lumen. Numerous small vesicles were often contained in the apical cytoplasm. The numerous small invaginations of the apical and lateral cell surfaces suggested active transportation of luminal substances. No canaliculi existed in the apical cytoplasm of M cells whereas they were often detected in the neighbouring microvillous epithelial cells. A noteworthy finding was the frequent detection of multivesicular bodies in the apical cytoplasm of M cells. These multivesicular bodies suggest some degradation of ingested luminal substances during transcytoplasmic transportation. WGA and 4 other lectins strongly reacted with all epithelial cells except for M cells, this negativity suggesting a means of detecting M cells in chicken caecal tonsils. Three lectins, DSL, ConA and Jacalin, reacted weakly with the glycocalyx on M cells. The positive reactivity might allow chicken M cells to be utilised for specific antigen delivery into the mucosal immune system in some parenteral vaccinations.
Histochemical localisation of versican, aggrecan and hyaluronan in the developing condylar cartilage of the fetal rat mandible
Authors: SHIBATA SHUNICHI , FUKADA KENJI , SUZUKI SHOICHI , OGAWA TAKUYA , YAMASHITA YASUO
Published: March 2003

We investigated the histochemical localisation of versican, aggrecan and hyaluronan in the developing condylar cartilage of the fetal rat mandible at d 15–17 of gestation. At d 15 of gestation, immunostaining for versican was detected in the anlage of the future condylar process (condylar anlage), although the staining intensity showed a considerable regional variation. At d 16 of gestation, a metachromatically stained matrix firstly appeared in the condylar anlage. Aggrecan, hyaluronan and versican were simultaneously detected in this newly formed condylar cartilage. At d 17 of gestation, immunostaining for versican became restricted to the perichondrium and was barely detected in the cartilage. Colocalisation of versican and aggrecan was also seen in the cranial base cartilage at d 14 of gestation. These results indicate that although versican is replaced by aggrecan during the transition from prechondrogenic tissue to cartilage, both molecules were temporally colocalised in the newly formed cartilage. A hyaluronan‐rich, low‐versican area was identified in the posterior end of the condylar anlage during d 15–17 of gestation. The existence of this area is a unique structural feature of the developing condylar cartilage.
The afferent connections of the posterior hypothalamic nucleus in the rat using horseradish peroxidase
Authors: ÇAVDAR SAFİYE , ONAT FİLİZ , AKER REZZAN , ŞEHİRLİ ÜMİT , ŞAN TANGUL , RACİ YANANLI HASAN
Published: March 2003

The posterior hypothalamic nucleus has been implicated as an area controlling autonomic activity. The afferent input to the nucleus will provide evidence as to its role in autonomic function. In the present study, we aimed to identify the detailed anatomical projections to the posterior hypothalamic nucleus from cortical, subcortical and brainstem structures, using the horseradish peroxidase (HRP) retrograde axonal transport technique in the rat. Subsequent to the injection of HRP into the posterior hypothalamic nucleus, extensive cell labelling was observed bilaterally in various areas of the cerebral cortex including the cingulate, frontal, parietal and insular cortices. At subcortical levels, labelled cells were observed in the medial and lateral septal nuclei, the bed nucleus of stria terminalis, and various thalamic and amygdaloid nuclei. Also axons of the vertical and horizontal limbs of the diagonal band were labelled and labelled cells were localised at the CA1 and CA3 fields of the hippocampus and the dentate gyrus. The brainstem projections were from the medial, lateral and parasolitary nuclei, the intercalated nucleus of the medulla, the sensory nuclei of the trigeminal nerve, and various reticular, vestibular, raphe and central grey nuclei. The posterior hypothalamic nucleus also received projections from the lateral and medial cerebellar nuclei and from upper cervical spinal levels. The results are discussed in relation to the involvement of the posterior hypothalamic nucleus in autonomic function and allows a better understanding of how the brain controls visceral function.
Neutrophil migration in tonsils
Authors: EBENFELT ANDERS , IVARSSON MAGNUS
Published: March 2003

Recent studies have indicated the existence of an active cellular defence in the secretion on the tonsillar surface. This defence seems to consist partly of physiologically active neutrophils and is present in health and during disease. The present study was undertaken to examine the migration of these neutrophils to the secretion on the mucosal surface. Tonsils from 6 patients with acute tonsillitis and 5 patients with snoring problems were removed and sectioned. Sections were stained immunohistochemically against CD15 to visualise neutrophils. Other sections were stained with acridine orange to detect bacteria. Clusters of neutrophils were frequently seen in tonsils both from patients with acute tonsillitis and from snorers. They were observed to be accumulated within the tonsillar epithelial layer. Streaks of neutrophils could be observed running not only from vessels mainly near or within the epithelium to the epithelial surface, but also from vessels far from the epithelium through the extrafollicular areas to the epithelial surface. Bacteria were not present in the epithelium. We consider that the findings indicate an active physiological migration of neutrophils to the tonsillar surface.
Investigation of feline brain anatomy for the detection of cortical spreading depression with magnetic resonance imaging
Authors: SMITH J. M. , JAMES M. F. , BOCKHORST K. H. J. , SMITH M. I. , BRADLEY D. P. , PAPADAKIS N. G. , CARPENTER T. A. , PARSONS A. A. , LESLIE R. A. , HALL L. D. , HUANG C. L.‐H.
Published: March 2003

Cortical spreading depression (CSD) and peri‐infarct depolarisation (PID) are related phenomena that have been associated with the human clinical syndromes of migraine (CSD), head injury and stroke (PID). Nevertheless the existence of CSD in man remains controversial, despite the detection of this phenomenon in the brains of most, if not all, other animal species investigated. This failure to unambiguously detect CSD clinically may be at least partly due to the anatomically complex, gyrencephalic structure of the human brain. This study was designed to establish conditions for the study of CSD in the brain of a gyrencephalic species using the noninvasive technique of magnetic resonance imaging (MRI). The 3‐dimensional (3D) gyrencephalic anatomy of the cat brain was examined to determine the imaging conditions necessary to detect CSD events. Orthogonal transverse, sagittal and horizontal T1‐weighted image slices showed that the marginal and suprasylvian gyri were the most appropriate cortical structures to study CSD. This was in view of (1) their simple geometry: (2) their lengthy extent of grey matter orientated rostrocaudally in the cortex: (3) their separation by a sulcus across which CSD spread could be studied and (4) the discontinuity in the grey matter in these regions between the right and left hemispheres dorsal to the corpus callosum. The structure suggested by the T1‐weighted images was corroborated by systematic diffusion tensor imaging to map the fractional anisotropy and diffusion trace. Thus a single horizontal image plane could visualise the neighbouring suprasylvian and marginal gyri of both cerebral hemispheres, whereas its complex shape and position ruled out the ectosylvian gyrus for CSD studies. With the horizontal imaging plane, CSD events were reproducibly detected by animating successive diffusion‐weighted MR images following local KCl stimulation of the cortical surface. In single image frames, CSD detection and characterisation required image subtraction or statistical mapping methods that, nevertheless, yielded concordant results. In repeat experiments, CSD events were qualitatively similar in appearance whether elicited by sustained or transient KCl applications. Our experimental approach thus successfully describes cat brain anatomy in vivo, and elucidates the necessary conditions for the application of MRI methods to detect CSD propagation.
Posterolateral tunnels and ponticuli in human atlas vertebrae
Authors: HASAN MAHDI , SHUKLA SANJEEV , SHAKIL SIDDIQUI M. , SINGH DHANRAJ
Published: March 2003

The posterolateral tunnel on the superior surface of the first cervical (atlas) vertebra is of normal occurrence in monkeys and other lower animals, but its presence in the form of a tunnel‐like canal, for the passage of the third part of the vertebral artery over the posterior arch of the human atlas vertebra is not reported. The aim of the present study was to detect the presence of such a canal, in addition to other types of ponticuli (little bridges) reported by earlier investigators, in macerated atlas vertebrae and routine cadaveric dissections. The posterolateral tunnel was detected in 1.14%, and the posterior and lateral ponticuli in 6.57 and 2% of vertebrae. Probably the bony roof of the posterolateral tunnel serves the purpose of additional lateral extension for the attachment of the posterior atlanto‐occipital membrane in quadrupeds, where the load of the head is supported by the extensor muscles of the neck, ligaments and posterior atlanto‐occipital membrane. In man, where the weight of the head is borne by the vertical loading of the superior articular process of the atlas, the roof of the tunnel has disappeared.
The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites
Authors: BENJAMIN M. , McGONAGLE D.
Published: March 2003

The 2 major categories of idiopathic inflammatory arthritis are rheumatoid arthritis and the seronegative spondyloarthropathies. Whilst the synovium is the primary site of joint disease in the former, the primary site in the latter is less well defined. However, it has recently been proposed that enthesitis‐associated changes in the spondyloarthropathies are primary and that all other joint manifestations are secondary. Nevertheless, some of the sites of disease localisation have not been adequately explained in terms of enthesitis. This article summarises current knowledge of the structure, function, blood supply, innervation, molecular composition and histopathology of the classic enthesis (i.e. the bony attachment of a tendon or ligament) and introduces the concept of ‘functional’ and articular ‘fibrocartilaginous’ entheses. The former are regions where tendons or ligaments wrap‐around bony pulleys, but are not attached to them, and the latter are synovial joints that are lined by fibrocartilage rather than hyaline cartilage. We describe how these 3 types of entheses relate to other, and how all are prone to pathological changes in spondyloarthropathy. We propose that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.
Surface antigens of human embryonic stem cells: changes upon differentiation in culture*
Authors: Draper Jonathan S. , Pigott Christine , Thomson James A. , Andrews Peter W.
Published: March 2003

We have analysed the surface antigen phenotype of a human embryonic stem (hES) cell line (H7) and the changes that occur upon differentiation induced by retinoic acid, hexamethylene bisacetamide and dimethylsulphoxide. The undifferentiated stem cells expressed Stage Specific Embryonic Antigen‐3 (SSEA3), SSEA4, TRA‐1‐60, and TRA‐1‐8 but not SSEA1. In these characteristics they closely resemble human embryonal carcinoma (EC) cells derived from testicular teratocarcinomas, and are distinct from murine EC and ES cells. The undifferentiated cells also expressed the liver/bone/kidney isozyme of alkaline phosphatase detected by antibody TRA‐2‐54, the class 1 major histocompatability antigens, HLA‐ABC, and the human Thy1 antigen. Differentiation of hES cells was induced by retinoic acid, HMBA and DMSO with the appearance of various cell types including neurons and muscle cells. The surface antigens characteristically expressed by hES cells were down‐regulated following induction of differentiation and other antigens appeared, notably several ganglioside glycolipids detected by antibodies VIN‐IS‐56 (GD3 and GD2), VIN‐2PB‐22 (GD2), A2B5 (GT3) and ME311 (9‐O‐acetyl‐GD3). Whereas the expression of HLA was slightly down‐regulated upon differentiation, its expression was strongly induced by interferon‐γ in both the undifferentiated and the differentiated cells, although the induction in the differentiated cultures was considerably stronger than in the stem cells. In all of these features the human ES cells, and their pattern of differentiation, resembled the pluripotent human EC cell line NTERA‐2 although clearly the range of cells generated by the hES cells was considerably greater.
A background to nuclear transfer and its applications in agriculture and human therapeutic medicine*
Authors: Campbell Keith H. S.
Published: March 2003

The development of a single celled fertilized zygote to an animal capable of reproduction involves not only cell division but the differentiation or specialization to numerous cell types forming each tissue and organ of the adult animal. The technique of nuclear transfer allows the reconstruction of an embryo by the transfer of genetic material from a single donor cell, to an unfertilized egg from which the genetic material has been removed. Successful development of live offspring from such embryos demonstrates that the differentiated state of the donor nucleus is not fixed and can be reprogrammed by the egg cytoplasm to control embryo and fetal development. Nuclear transfer has many applications in agriculture and human medicine. This article will review some of the factors associated with the success of embryo development following nuclear transfer and outline the potential uses of the technology.
Signals that determine Schwann cell identity*
Authors: Jessen K. R. , Mirsky R.
Published: March 2003

While the signals that direct neural crest cells to choose the glial lineage and generate Schwann cell precursors are still obscure, studies bothin vivoandin vitroindicate that the survival and differentiation of these cells to form Schwann cells is regulated by at least two signals, neuregulin‐1 and endothelin. We know little about the signals that cause some immature Schwann cells to choose myelin differentiation, while other cells form non‐myelinating cells. Three transcription factors, Sox‐10, Oct‐6 and Krox‐20, have been shown to play key roles in the Schwann cell lineage. The transcription factor Krox‐20 has been identified as a major target of the signals that induce myelin differentiation. Gene transfer experimentsin vitroshow that this protein has a remarkable ability to promote a large number of phenotypic changes in immature Schwann cells that characterize the transition of these cells to myelinating cells. Furthermore, Krox‐20 shows important functional interactions with neuregulin and transforming growth factor β (TGFβ), two factors that have been implicated in the regulation of myelination in postnatal nerves. Another signal of importance in developing peripheral nerves, Desert Hedgehog, secreted by Schwann cells directs formation of the peripheral nerve connective tissue sheaths. Ongoing gene screening experiments are likely to reveal new genes of interest in this system.
Improved digital SEM of cancellous bone: scanning direction of detection, through focus for in‐focus and sample orientation
Authors: Boyde Alan
Published: March 2003

Three‐dimensional (3D) study of cancellous bone tissue organization is necessary to understand how modelling and remodelling processes regulate bone structure and connectivity. It requires imaging methods that have both sufficient resolution power and width and depth of field. Since clinical imaging methods fall far short of the first requirement, we can only study prepared tissue in isolation from the body. Scanning electron microscopy (SEM) of macerated plane parallel slices is the most productive method, but we meet special technical problems in imaging porous bone because samples need to be relatively thick to maintain both continuity and context. Problems due to charging under the electron beam can be controlled by imaging with only high‐energy backscattered electrons (BSE). This gives an important additional benefit that the direction of apparent illumination can be manipulated by positioning the detector, and multiple detector positions can be employed strategically to generate images in which colour is used to help in coding surface morphology. However, we next confront the difficulty of the limited depth of field. This can be improved by taking series of images, moving the sample along the electron optic axis, and combining these to generate a single extended‐focus image. SEM imaging geometry gives a change in magnification with change of working distance, and it is shown that this must be corrected for each image of the through‐focus sequence. Colour coding the lighting direction and increasing the depth of field are approaches that can be combined, and are well matched to the possibilities offered by communication by digital data projection. Finally, the latter means also offer another powerful technique for 3D representation through the display of through tilt image sequences. The novel routines considered here are generally applicable to all classes of microanatomical SEM sample.
Immunocytochemical investigation of neurovascular relationships in human tooth pulp
Authors: Rodd Helen D. , Boissonade Fiona M.
Published: March 2003

This study sought to explore the anatomical relationships between peptidergic nerves and blood vessels within human primary and permanent teeth. Extracted primary and permanent molars (n = 120) were split longitudinally, placed in Zamboni's fixative and the coronal pulps were processed for indirect immunofluorescence. Ten‐micrometre‐thick serial frozen pulp sections were triple‐labelled using combinations of the following antisera: (1) protein gene‐product 9.5 (PGP 9.5), a general neuronal marker; (2) one of the neuropeptides, calcitonin gene‐related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) or neuropeptide Y (NPY); and (iii) the lectin Ulex europeus, a label for vascular endothelium. The mid‐coronal pulp region was examined, using fluorescence microscopy, to determine the proportion of blood vessels showing a positive innervation (recorded when PGP 9.5‐labelled nerves appeared to intersect the vessel wall). In addition, the percentage of these vascular‐related nerves expressing each of the above neuropeptides was recorded. Overall, 20% of pulpal blood vessels appeared to have a positive innervation. In the main these were thick‐walled arterioles. Capillaries, venules and lymphatics were mostly devoid of an associated innervation. Ninety‐two per cent of vascular‐related nerves expressed CGRP, 87% expressed SP, 15% expressed VIP and 80% expressed NPY. There were no significant differences in overall innervation or peptide‐related innervation between primary and permanent teeth (P < 0.05, anova), indicating that pulpal blood flow is likely to be subject to similar neurological control mechanisms in both dentitions.
Purification and characterization of invertases from leaves of Lolium temulentum
Authors: WALKER R. P. , WINTERS A. L. , POLLOCK C. J.
Published: March 2003

Leaves of Lolium temulentum L. contain both low and high pI acid invertases. Immunoblot analysis of a highly purified preparation of these forms suggested that they both possess a subunit molecular weight of 68 kDa. Protoplasts and their derived vacuoles were isolated from leaf blades and contained sufficient acid invertase activity to account for all the activity found in the soluble fraction of crude homogenates of leaf blades. Alkaline invertase was present in the basal region of leaves and, unlike acid invertase, did not bind to Con A‐Sepharose, suggesting that the acid invertase was a glycoprotein and that the alkaline invertase was not. Fructose inhibited both acid and alkaline invertases. The hypothesis is discussed that activity in vivo could be modulated by the concentration of free fructose.
Seasonal variation of fructan‐β‐fructosidase (FEH) activity and characterization of a β‐(2‐1)‐linkage specific FEH from tubers of Jerusalem artichoke (Helianthus tuberosus)
Authors: MARX STEFAN P. , NÖSBERGER JOSEF , FREHNER MARCO
Published: March 2003

The fructan‐β‐fructosidase activity (1‐FEH; EC 3.2.1.80) that degrades inulin in tubers of Helianthus tuberosus L. appears to be developmentally regulated; it was low in growing tubers but increased during dormancy and sprouting. In spite of relatively high 1‐FEH activity in vitro, fructose concentration was very low in developing and dormant tubers and increased markedly only during sprouting. A fructan‐β‐fructosidase from such sprouting tubers was purified 41‐fold to a single protein band on one‐dimensional sodium dodecylsulphate‐polyacrylamide gels. The purification procedure included ammonium sulphate precipitation, lectin‐affinity chromatography on concanavalin A, anion‐exchange and cation‐exchange chromatography. The enzyme had an apparent molecular mass of 75000 measured by size‐exclusion chromatography, and 79000 measured by one‐dimensional sodium dodecylsulphate‐polyacrylamide gel electrophoresis. It exhibited a high substrate specificity, hydrolysing terminal β‐(2‐1)‐fructosyl‐fructose‐linkages in linear and branched fructan oligomers; β‐(2‐6)‐linkages were hardly hydrolysed. Hydrolysis of inulin oligomers followed normal saturation kinetics: Km values for 1,1‐kestotetraose and 1,1,1‐kestopentaose were 8‐3 mM and 12 mM, respectively. Fructosyl residues were hydrolysed from inulin oligomers by a multi‐chain mechanism. The fructan‐β‐fructosidase showed optimal enzyme activity at pH 5–2, and it retained its full activity after pre‐incubation for 1 h at up to 40°C. The release of fructose from 5 mm 1,1‐kestotetraose was reduced by 25 % when 1‐FEH was assayed in the presence of 10 mM sucrose. It is proposed that the inhibition of 1‐FEH activity by sucrose is a mechanism for controlling fructan degradation in planta.
Fructan oligomers in Poa ampla
Authors: CHATTERTON N. J. , HARRISON P. A.
Published: March 2003

Ion exchange chromatography of water extracts was used to classify the fructans in leaves of 40 temperate dicots and 110 temperate grass species. Of the 150 species studied, only Poa ampla (Merrill) contained a single β‐2,6 linked fructan series. All other species grown at 10/5°C day/night temperatures (16 h day) contained some β‐1,2 linked oligofructans, even when the major fructan series was β‐2,6 linked. Leaves of P. ampla plants grown at 15/10°C day/night temperatures contained some β‐1,2 linked fructans and raffinose in addition to the dominant β‐2,6 series, but did not contain significant amounts of 1‐kestose or bifurcose (1&6‐kestotetraose). Leaves of Poa arctica R.Br. and Poa bulbosa L. contained significant amounts of raffinose and various β‐1,2 linked oligomers but no 1‐kestose. In vivo synthesis of 6‐kestose in leaves of P. ampla grown at 10/5°C proceeds in the absence of significant amounts of either 1‐kestose or bifurcose. Thus P. ampla probably has a specific 6‐SST (6‐sucrose‐sucrosefructosyl transferase) and might provide a ready source of β‐2,6 linked grass fructan.
Copper and nickel uptake, accumulation and tolerance in Typha latifolia with and without iron plaque on the root surface
Authors: YE Z. H. , BAKER A. J. M. , WONG M. H. , WILLIS A. J.
Published: March 2003

summary

The effects of iron plaque on the growth of Typha latifolia L. and accumulation of copper and nickel in T. latifolia were investigated under laboratory conditions in nutrient solution cultures. Seedlings with and without iron plaque on their roots were exposed to 0.05 μg ml−1 Cu and 0.10 μg ml−1 Ni solutions for 72 d. The results showed no differences in root and shoot d. wt and leaf elongation when Cu or Ni were added to the solution and in the presence or absence of plaque. However, root length was reduced by Cu and Ni, and the reduction in root length was greater in the presence of plaque. Some Cu and Ni was adsorbed on root surfaces; roots with plaque took up more Cu, but less Ni than those without. The presence of plaque did not alter Cu uptake and translocation but increased Ni uptake and translocation. Most of the Cu and Ni taken up was retained in the roots, suggesting that the root tissue rather than the root surface or plaque is the main barrier for Cu and Ni transport. The results differ from those reported for other species.
Effects of the spatial arrangement of aerial stems and current‐year shoots on the demography and growth ofHydrangea hirtain a light‐limited environment
Authors: ISHII HIROAKI , TAKEDA HIROSHI
Published: March 2003

summary

This study investigates the effects of the spatial arrangement of aerial stems and current‐year shoots on patterns of herbivory, competition and on the requirements for mechanical support inHydrangea hirtaSieb. et Zucc. growing in a light‐limited environment. Stem demography was followed for three consecutive growing seasons. Stem mortality rates decreased with increasing stem age. Age‐specific mortality rate was highest for new stems owing to the high incidence of herbivory. Mortality due to herbivory was low in older stems and was attributed to the dispersion of the risk of herbivore attack as a result of the increase in number of current‐year shoots per stem. Clumping of stems led to intense intra‐clonal competition as inferred from size‐dependent mortality and density‐dependent turnover of stems, and higher maximum stem length in clumps with higher stem density. Analysis of the spatial distribution of current‐year shoots within the stem crown revealed a uniform, mono‐layered crown architecture. The horizontal distribution of buds within the mono‐layer was aggregated as a result of their opposite position, but as current‐year shoots grew, their apices became uniformly distributed, resulting in efficient leaf display for light capture and shading out competing stems. However, limits on stem growth were observed in crown expansion, shoot production rate and current‐year shoot size. Crown width increased with increasing basal diameter to reach a maximum. Both shoot production rate and current‐year shoot size decreased with stem growth and a minimum current‐year shoot size was defined. These limits on stem growth were attributed to suppression from intra‐clonal competition and to the requirements for mechanical support of the mono‐layered crown.
Relationships between ozone resistance and climate in European populations of Plantago major
Authors: LYONS TOM M. , BARNES JEREMY D. , DAVISON ALAN W.
Published: March 2003

summary

The relative ozone resistance of 20 European and two American populations of Plant ago major was examined, and relationships with climatic factors at the source of the plant material were explored using data provided by participants in the ICP‐Crops initiative (International Co‐operative Programme to Investigate the Effects of Air Pollutants and Other Stresses on Agricultural and Semi‐Natural Vegetation). Plants grown from seed were exposed to either charcoal/Purafil® filtered air (CF < 5 nmol mol−1 O3) or CF + ozone (70 nmol mol−1 O3 7 h d−1) over a 2‐wk period in controlled environment chambers, and effects on mean plant relative growth rate (R) and allometric root/shoot growth (K) determined. Ozone resistance (R%) was calculated from (R03/RCF) × 100.

Populations exhibited contrasting sensitivities to ozone, without the development of typical visible symptoms of injury. A positive relationship was found between relative ozone resistance and descriptors of the ozone‐climate at the site of seed collection for the year of, and the 2 yr before, seed collection. The best predictors of inherent ozone resistance were shown to be cumulative ozone exposure indices calculated according to current United Nations Economic Commission for Europe (UN‐ECE) critical level guidelines for the pollutant (i.e. the accumulated hourly average ozone exposure over a threshold level of 40 nmol mol−1 (AOT40) or 30 nmol mol−1 (AOT30) calculated during daylight hours for the consecutive 3‐month period of the year experiencing the highest ozone concentrations). No relationships were found between ozone resistance and climatic factors (temperature, precipitation, sunshine hours, humidity) or the concentrations of other air pollutants (SO2, NO2, NO).

These findings support the view that current ambient levels of ozone in many regions of Europe are high enough to promote evolution of resistance to the pollutant in native plant populations. The significance of these findings to the debate over the establishment of separate critical levels for the protection of natural and semi‐natural vegetation is discussed.
Water uptake by safflower and wheat roots infected with arbuscular mycorrhizal fungi
Authors: BRYLA D. R. , DUNIWAY J. M.
Published: March 2003

The objective of this study was to determine if infection by arbuscular mycorrhizal fungi alters water uptake by roots under well watered to severely droughted conditions. Safflower and wheat plants were grown with and without the mycorrhizal fungi, Glomus etunicatum or G. intraradices in nutrient‐amended soil under environmentally controlled conditions to yield mycorrhizal and non‐mycorrhizal plants with similar leaf areas, root length densities, d. wt, and adequate tissue phosphorus and nitrogen. Specific water uptake rates (cm3 of water cm−1 root length d−1) were estimated non‐destructively at various depths in the soil from changes in the soil water content measured using a gamma attenuation method. When soil water was severely depleted, changes in soil water potentials were also measured with soil psychrometers. Roots from both plant species extracted water at the fastest rate from the upper soil layers when the soil water content was high, and later, extracted water primarily from deeper depths as water in the upper soil layers was depleted. Mycorrhizal infection did not affect the rates at which roots extracted water from soil whether soil moisture conditions were at their wettest condition, at container capacity, or at the driest extreme when soil water potentials ranged from −1.5 to −2.0 MPa and the plants were completely wilted. Plant water relations were also largely unaffected by infection. Mycorrhizal infection did not alter the ability of plants to extract water from soil even during extreme drought.
A cytogenetic approach to the improvement of aluminium tolerance in wheat
Authors: MILLER T. E. , IQBAL N. , READER S. M. , MAHMOOD A. , CANT K. A. , KING I. P.
Published: March 2003

summary

High levels of soil aluminium place serious constraints on wheat production on acidic soils, especially in the tropical areas of Africa and South America. Conventional plant breeding has improved the tolerance of the wheat crop, but available genetic variation is limited. The wild relatives of wheat provide a valuable gene pool for the introduction of further genetic variation. One wild species, Aegilops uniaristata Vis. (2n = 2x = 14,NN), is being utilized as a new source of tolerance. Of the addition lines of individual N genome chromosomes of A. uniaristata to wheat (Triticum aestivum L.) which have been established and characterized, chromosome 3N has been shown to confer tolerance to wheat. The three substitution lines in which 3N replaces the homoeologous wheat chromosomes, 3A, 3B or 3D, have also been produced. Growing plants to maturity in a low pH/high Al hydroponics system confirmed that chromosome 3N conferred tolerance to the substitution lines as well as to the addition line. By manipulating the genetic control of homoeologous chromosome pairing, chromosome 3N is being recombined with its wheat homoeologues in order to introduce a smaller alien segment which carries the gene(s) for tolerance but not the agronomically unacceptable brittle rachis gene also carried on chromosome 3N.
Markers and mapping: we are all geneticists now
Authors: JONES NEIL , OUGHAM HELEN , THOMAS HOWARD
Published: March 2003

summary

This is a review of genetic mapping with molecular markers aimed at the non‐specialist who wishes to use, or at least grasp the concepts behind, this powerful analytical tool. Restriction fragment length polymorphisms (RFLPs) are defined and used to illustrate the different aspects of mapping. The principles of segregation, recombination and linkage are considered and related to the idea of a molecular marker map. A description of a typical mapping population and how it is analysed follows. Traits to be mapped are divided into those controlled by ‘major’ genes and those governed by quantitative trait loci (QTLs). Exploitation of the map for marker‐assisted selection, gene cloning and synteny comparisons is discussed, as are some of the limitations to the usefulness of molecular marker maps. Finally other marker systems are introduced, namely minisatellites or variable number tandem repeats (VNTRs); randomly amplified polymorphic DNA (RAPDs); microsatellites or simple sequence repeats (SSRs); and amplified fragment length polymorphisms (AFLPs).
The plant cell wall is altered by inhibition of polyamine biosynthesis
Authors: BERTA G. , ALTAMURA M. M. , FUSCONI A. , CERRUTI F. , CAPITANI F. , BAGNI N.
Published: March 2003

summary

Polyamines (PAs) and the cell wall have important roles in plant morphogenesis. An interaction between cell wall components (pectic substances) and polyamines is known and inhibition of polyamine biosynthesis induces inhibition of some morphogenic processes. This is the case of rhizogenesis in tobacco (Nicotiana tabacum L.) thin layers. This paper investigates whether inhibition of polyamine biosynthesis induces modifications in the structure, shape and size of the primary cell walls in tobacco thin layers cultured on a rhizogenic medium, and whether polyamines (putrescine and spermidine) administered in combination with their corresponding inhibitors dl‐α‐difluoromethylomithine +dl‐α‐difluoromethylarginine (DFMO + DFMA), cyclohexylamine (CHA), methylglyoxal‐bis(guanylhydrazone) (MGBG) restore cell wall characteristics. In treatments with polyamine inhibitors, cell hypertrophy occurred in the lowermost layer of the explant in contact with the medium. Many unusual features were observed in the walls of the hypertrophic cells: an amorphous structure, loosening of the fibrillar component; detachment between contiguous cells, lysis of wall components and an uneven thickness often giving a wavy appearance (in transverse walls). The inhibitors reduced cell wall thickness, and caused a weak positive PATAg reaction for polysaccharides. Polyamines restored cell wall thickness and, in general, the other wall features. Our results show that polyamines are necessary for maintaining cell wall characteristics by strengthening the links between cell‐wall components.