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PubMed1987

[Use of a radial flap of the forearm in plastic and reconstructive surgery of the extremities].

A detailed characteristic of the ways of using fascio-cutaneous, osteo-cutaneous and muscular-cutaneous flaps disposed in the basin of the radial vascular bundle is given on the basis of an experience with 18 operations. Non-free plasty by an island flap on a peripheral vascular pedicle was used in 13 patients. Free plasty with microvascular anastomoses was used in 4 patients. In 16 of the 17 patients a complete take of the flap took place.

Arm Injuries↗
PubMed1990

Blood supply of the flexor digital tendon in the hand and its clinical significance.

An anatomical study on the blood sources and vascularity of the flexor digital tendon was conducted in the upper extremities of fresh cadavers by means of arterial injection and meticulous dissection of the transparent tendon under the microscope. According to whether or not synovial membrane surrounded the tendon, the flexor digital tendon can be divided into 2 regions: non-synovial and synovial. The major intrinsic blood supply of the digital tendon was in the form of longitudinal vascular bundles, while the transverse anastomotic branches were short and sparse. The non-synovial region of the tendon was covered by paratenon and the vascular distribution of this region was uniform. In the synovial sheath, the blood vessels distributed only on the dorsal side, while the volar side was devoid of vessels. The profundus and superficialis tendons had an avascular zone at the proximal interphalangeal and metacarpophalangeal joints respectively. It was considered that the difference of the vascular architecture might be related to the mechanical force to which the tendon was subjected. The nutrition of tendon was discussed and the selection of tendon graft at operation was suggested.

Hand↗
PubMed2003

APL regulates vascular tissue identity in Arabidopsis.

Vascular plants have a long-distance transport system consisting of two tissue types with elongated cell files, phloem and xylem. Phloem has two basic cell types, enucleate sieve elements and companion cells. Xylem has various lignified cell types, such as tracheary elements, the differentiation of which involves deposition of elaborate cell wall thickenings and programmed cell death. Until now, little has been known about the genetic control of phloem-xylem patterning. Here we identify the ALTERED PHLOEM DEVELOPMENT (APL) gene, which encodes a MYB coiled-coil-type transcription factor that is required for phloem identity in Arabidopsis. Phloem is established through asymmetric cell divisions and subsequent differentiation. We show that both processes are impaired by a recessive apl mutation. This is associated with the formation of cells that have xylem characteristics in the position of phloem. The APL expression profile is consistent with a key role in phloem development. Ectopic APL expression in the vascular bundle inhibits xylem development. Our studies suggest that APL has a dual role both in promoting phloem differentiation and in repressing xylem differentiation during vascular development.

Arabidopsis↗
PubMed1985

Photosynthesis, Morphology, Leaf Anatomy, and Cytogenetics of Hybrids between C(3) and C(3)/C(4)Panicum Species.

The Laxa group of the Panicum genus contains species which have CO(2) exchange and anatomical characteristics intermediate to C(3) and C(4) photosynthetic types (C(3)/C(4)), and also species characterized as C(3). Hybrids were made between two of the C(3)/C(4) species and two C(3) species. Carbon dioxide exchange and morphological, leaf anatomical, and cytogenetic characteristics of F(1) hybrids between Panicum milioides Nees. ex Trin (C(3)/C(4)) and P. laxum Mez. (C(3)), P. spathellosum Doell (C(3)/C(4)) and P. boliviense Hack. (C(3)), and P. spathellosum and P. laxum were studied. There were no consistent differences in apparent photosynthesis, although two of the three hybrids had higher net CO(2) uptake than the C(3) parent. Values of inhibition of apparent photosynthesis by 21% O(2), CO(2) loss in the light, and CO(2) compensation concentration for the hybrids were between those of the parents. All three hybrids showed leaf anatomical traits, especially organelle quantities in the bundle sheath cells, between those of their respective parents. Linear regression of CO(2) compensation concentration on the percentage of mitochondria and chloroplasts in vascular bundle sheaths of the parents and hybrids gave correlation coefficients of -0.94. This suggests that the reduction in CO(2) loss in the C(3)/C(4) species, and to a lesser degree in the F(1) hybrids, was due to development of organelles and perhaps a higher proportion of leaf photorespiration in bundle sheaths. The overall morphology of the hybrids was so different from the parents that they could be described as new taxonomic forms. The chromosomes in the hybrids were mainly unpaired or paired as bivalents indicating possible homology between some parental genomes.

Journal Article↗
PubMed2001

Cellular compartmentation of ammonium assimilation in rice and barley.

This review describes immunolocalization studies of the tissue and cellular location of glutamine synthetase (GS; EC 6.3.1.2) and glutamate synthase (Fd GOGAT; EC 1.4.7.1 and NADH-GOGAT; EC 1.4.1.14) proteins in roots and leaves of rice (Oryza sativa L.) and barley (Hordeum vulgare L.). In rice, cytosolic GS (GS1) protein was distributed homogeneously through all cells of the root. NADH GOGAT protein was strongly induced and its cellular location altered by ammonium treatment, becoming concentrated within the epidermal and exodermal cells. Fd GOGAT protein location changed with root development, from a widespread distribution in young cells to becoming concentrated within the central cylinder as cells matured. Plastid GS protein was barely detectable in rice roots, but was the major isoform in leaves, being present in the mesophyll and parenchyma sheath cells. GS1 was specific to the vascular bundle, as was NADH GOGAT, whereas Fd GOGAT was primarily found in mesophyll cells. In barley roots, GS1 protein was found in the cortical and vascular parenchyma and its concentration was highest in N-deficient seedlings. Plastid GS protein was detected in both cortical and vascular cells, where different plastid forms, containing different concentrations of GS protein, were identified. In barley leaves, GS2 protein was detected in the mesophyll chloroplasts and GS1 was found in the mesophyll and vascular cells. N nutrition strongly influenced this distribution, with a marked increase in GS1 concentration in the vascular cells in response to nitrate and ammonium, and an increase in mesophyll GS2 concentration in nitrate-grown seedlings. Fd GOGAT protein was found in both the mesophyll and vascular plastids. These localization studies show that the GS/GOGAT cycle is highly compartmentalized at both the subcellular and cellular levels. Reasons for this compartmentation, and the roles of each isoform, are discussed.

Cell Compartmentation↗
PubMed2003

The cellular localization of prosystemin: a functional role for phloem parenchyma in systemic wound signaling.

The systemin precursor, prosystemin, has been previously shown to be sequestered in vascular bundles of tomato ( Lycopersicon esculentum Mill.) plants, but its subcellular compartmentalization and association with a specific cell type has not been established. We present in situ hybridization and immunocytochemical evidence at the light, confocal, and transmission electron microscopy levels that wound-induced and methyl jasmonate-induced prosystemin mRNA and protein are exclusively found in vascular phloem parenchyma cells of minor veins and midribs of leaves, and in the bicollateral phloem bundles of petioles and stems of tomato. Prosystemin protein was also found constitutively in parenchyma cells of various floral organs, including sepals, petals and anthers. At the subcellular level, prosystemin was found compartmentalized in the cytosol and the nucleus of vascular parenchyma cells. The cumulative data indicate that vascular phloem parenchyma cells are the sites for the synthesis and processing of prosystemin as a first line of defense signaling in response to herbivore and pathogen attacks.

Animals↗
PubMed2003

Vascular adaptations for heat conservation in the tail of Florida manatees (Trichechus manatus latirostris).

Although Florida manatees (Trichechus manatus latirostris) have relatively low basal metabolic rates for aquatic mammals of their size, they maintain normal mammalian core temperatures. We describe vascular structures in the manatee tail that permit countercurrent heat exchange (CCHE) to conserve thermal energy. Approximately 1000 arteries juxtaposed to 2000 veins are found at the cranial end of the caudal vascular bundle (CVB); these numbers decrease caudally, but the 1:2 ratio of arteries to veins persists. Arterial walls are relatively thin when compared to those previously described in vascular countercurrent heat exchangers in cetaceans. It is assumed that CCHE in the CVB helps manatees to maintain core temperatures. Activity in warm water, however, mandates a mechanism that prevents elevated core temperatures. The tail could transfer heat to the environment if arterial blood delivered to the skin were warmer than the surrounding water; unfortunately, CCHE prevents this heat transfer. We describe deep caudal veins that provide a collateral venous return from the tail. This return, which is physically outside the CVB, reduces the venous volume within the bundle and allows arterial expansion and increased arterial supply to the skin, and thus helps prevent elevated core temperatures.

Adaptation, Physiological↗
PubMed2000

Developmental regulation of the maize Zm-p60.1 gene encoding a beta-glucosidase located to plastids.

A beta-glucosidase that cleaves the biologically inactive hormone conjugates cytokinin-O- and kinetin-N3-glucosides is encoded by the maize Zm-p60.1 gene. The expression of the Zm-p60.1 gene was analyzed by Northern blot analysis and in-situ hybridization. It was found that the expression levels of the Zm-p60.1-specific mRNA changed after pollination of carpellate inflorescences. The Zm-p60.1 cDNA was expressed in E. coli and antibodies were raised against this protein. An antibody was used to determine the tissue-specific localization of this protein. By in situ immunolocalization experiments, this protein was found to be located in cell layers below the epidermis and around the vascular bundles of the coleoptile. In the primary leaf, the Zm-p60.1 protein was detected in cells of the outermost cell layer and around the vascular tissue. In floral tissue, Zm-p60.1 was present in the glumes, the carpels and in the outer cell layer of the style. In coleoptiles, as determined by immuno-electronmicroscopy, the Zmp60.1 protein was located exclusively in the plastids.

Gene Expression Regulation, Developmental↗
PubMed1985

Photosynthetic gene expression and cellular differentiation in developing maize leaves.

We have exploited the positional gradient of cellular differentiation in Zea mays leaves to study the accumulation of mRNAs encoding subunits of the two CO(2)-fixing enzymes and the major chlorophyll-binding protein. These three proteins are differentially compartmentalized in the two photosynthetically active cell types of the leaf. Previous studies have shown that accumulation of the two carboxylases commences 2 to 4 cm from the base of the leaf (Mayfield SP, WC Taylor Planta 161: 481-486) at a position where bundle sheath and mesophyll cells show morphological evidence of maturation. The light-harvesting chlorophyll a/b protein accumulates progressively from the leaf base, as does its mRNA, in spite of its localization in mesophyll cells after cellular differentiation occurs. While small quantities of phosphoenolpyruvate carboxylase mRNA are detectable in the basal region of the leaf, significant mRNA accumulation is coincident with that of the polypeptide at 4 to 6 cm from the leaf base, the region where bundle sheath and mesophyll cells exhibit fully differentiated morphologies. mRNAs encoding the small and large subunits of ribulose 1,5-bisphosphate carboxylase accumulate to significant levels before bundle sheath cells are fully differentiated and before their polypeptides are detectable. Cytological examination indicates that this is the position at which the maturation of intermediate vascular bundles is first evident. Cytosolically localized small subunit mRNA and chloroplast-localized large subunit mRNA are complexed with polyribosomes at all positions of the leaf.

Journal Article↗
PubMed1988

High- and low-affinity binding sites for vasoactive intestinal peptide (VIP) in the rat kidney revealed by light microscopic autoradiography.

The distribution of VIP binding sites in rat kidney and adrenal gland has been examined by light microscopic autoradiography. A fully characterized mono-iodinated molecular form of VIP (M-125-I-VIP) which maintains the biological activity of the native peptide, was used for this study. Two types of VIP binding sites, with high and low affinity, have been identified. High affinity sites are associated with (i) glomerular structures in the cortex, (ii) the inner stripe of the outer medulla, possibly corresponding to Henle's loops and distal tubules, (iii) radiated structures in the inner zone of the medulla, likely to represent labeling of collecting ducts and/or vascular bundles and (iv) the adrenal cortex. Autoradiographic grains associated with low affinity sites are present diffusely throughout the renal cortex, possibly corresponding to labeling of tubular and/or vascular structures, and throughout the adrenal gland. These observations further delineate a role of VIP in renal and neuroendocrine function.

Animals↗
PubMed2002

Activation tagging of the two closely linked genes LEP and VAS independently affects vascular cell number.

The complex dominant Arabidopsis thaliana mutant lettuce (let) shows the conversion of the leaf petiole into a leaf blade caused by an ectopic leaf blade formation. This is the result of the activation tagging of the LEAFY PETIOLE (LEP) gene encoding an AP2/EREBP-like transcription factor. Here, we report that in addition to this leafy petiole phenotype, the size of the vascular bundles is increased in all aerial organs in let as a result of an increase in the number of xylem, phloem (pro)cambial and pericycle cells. This vascular phenotype is caused by activation tagging of the two genes VASCULAR TISSUE SIZE (VAS) and LEP. These genes are closely linked and arranged in tandem. Activation tagging of LEP only caused a specific increase in the number of xylem cells. This increased xylem cell number, together with the ectopic leaf blade formation, indicates that LEP functions as a cell division-promoting factor. The activation tagging of VAS only resulted in a specific increase in phloem (pro)cambial and pericycle cells. We conclude that activation tagging of LEP and VAS results in additive phenotypes. Insertional mutants for LEP and VAS display wild-type vascular development, indicating the relevance of activation tagging for functional analysis of novel genes involved in plant development.

Amino Acid Sequence↗
PubMed1997

RF2a, a bZIP transcriptional activator of the phloem-specific rice tungro bacilliform virus promoter, functions in vascular development.

Rice tungro bacilliform virus (RTBV) replicates only in phloem cells in infected rice plants and its promoter drives strong phloem-specific reporter gene expression in transgenic rice plants. We isolated a cDNA encoding a basic leucine zipper (bZIP) protein, RF2a, which binds to the Box II cis element that is important for expression from the promoter. RF2a, which stimulates Box II-dependent transcription in a homologous in vitro transcription system, accumulates in nuclei of phloem and certain other cell types in shoots, but is found at only very low levels in roots. Transgenic antisense plants in which RF2a accumulation was suppressed had normal roots but stunted, twisted leaves with small, disorganized vascular bundles, an enlarged sclerenchyma and large air spaces. We propose that the RTBV promoter exploits a host transcription factor that is critical for leaf tissue differentiation and vascular development for its expression.

Amino Acid Sequence↗
PubMed2001

[The supramalleolar flap. Our experience in 35 cases].

The authors report 35 cases of use of the supramalleolar flap described by Masquelet et al. in 1988. In 27 cases, the arterial blood supply was in a mixed (anterograde and retrograde) fashion since the perforating branch of the peroneal artery was spared. In eight cases the arterial blood supply was in a retrograde fashion due to the location of the skin loss. As described by Valenti et al. In 1991, the authors recommend the use of a distal subcutaneous pedicled to avoid skin grafting over the tendons at the distal part of the lag. In main cases of anterograde blood supply the superficial peroneal nerve could be spread. In 33 cases the plastic result was assessed as satisfactory. The coverage of the weight-bearing portion of the heel was done two times with no satisfactory result. Coverage of the medial malleolus area, Achilles tendon and dorsal skin of the foot represent the main indications and the best results. Five times, a venous congestion was observed with three cases of partial necrosis of the flap. The use of a large subcutaneous pedicle did not always prevent such venous problems, though this technical aspect improves the vascular reliability of the flap. The main local alternative is the distal pedicled sural flap that needs to divide the sural nerve and not allows coverage as distal as the supramalleolar flap. Except the distal coverage of the foot, the indications of these previous both flaps are similar. In case of foot coverage, the medial plantar flap based on the lateral plantar vascular bundle, as described by Martin et al. in 1991, is the other one local alternative. Free flaps are indicated for extensive skin losses, or when a poor distal vascularity of the leg does not allow reliability of distal pedicled flaps.

Adolescent↗
PubMed2003

Characterization of PTM5 in aspen trees: a MADS-box gene expressed during woody vascular development.

The vascular component of trees possesses some of the most specialized processes active in the formation of roots, stems, and branches, and its wood component continues to be of primary importance to our daily lives. The molecular mechanisms of wood development, however, remain poorly understood with few well-characterized regulatory genes. We have identified a vascular tissue-specific MADS-box gene, Populus tremuloides MADS-box 5 (PTM5) that is expressed in differentiating primary and secondary xylem and phloem. Phylogenetic analysis has shown that PTM5 is a member of the SOC1/TM3 class of MADS-box genes. Temporal expression analysis of PTM5 in staged vascular cambium and other tissues indicated that PTM5 expression is seasonal and is limited to spring wood formation and rapidly expanding floral catkins. Spatial expression analysis using in situ hybridization revealed that PTM5 expression is localized within a few layers of differentiating vascular cambium and xylem tissues as well as the vascular bundles of expanding catkins. Since many MADS-box genes are known to act as transcription factors, these results suggest that the coordinated expression of PTM5 with other vascular developmental genes may be a hallmark of the complex events that lead to the formation of the woody plant body.

Amino Acid Sequence↗
PubMed1995

Phloem-Specific Expression of Tyrosine/Dopa Decarboxylase Genes and the Biosynthesis of Isoquinoline Alkaloids in Opium Poppy.

Tyrosine/dopa decarboxylase (TYDC) catalyzes the formation of tyramine and dopamine and represents the first steps in the biosynthesis of the large and diverse group of tetrahydroisoquinoline alkaloids. Opium poppy accumulates morphine in aerial organs and roots, whereas sanguinarine, which is derived from a distinct branch pathway, accumulates only in roots. Expression of the TYDC gene family in opium poppy was investigated in relation to the organ-specific biosynthesis of these different types of alkaloids. Members of the TYDC gene family are classified into two groups (represented by TYDC1 and TYDC2) and are differentially expressed. In the mature plant, TYDC2-like transcripts are predominant in stems and are also present in roots, whereas TYDC1-like transcripts are abundant only in roots. In situ hybridization analysis revealed that the expression of TYDC genes is developmentally regulated. TYDC transcripts are associated with vascular tissue in mature roots and stems but are also expressed in cortical tissues at earlier stages of development. Expression of TYDC genes is restricted to metaphloem and to protoxylem in the vascular bundles of mature aerial organs. Localization of TYDC transcripts in the phloem is consistent with the expected developmental origin of laticifers, which are specialized internal secretory cells that accompany vascular tissues in all organs of select species and that contain the alkaloid-rich latex in aerial organs. The differential expression of TYDC genes and the organ-dependent accumulation of different alkaloids suggest a coordinated regulation of specific alkaloid biosynthetic genes that are ultimately controlled by specific developmental programs.

Journal Article↗
PubMed1994

Developmental and environmental regulation of the Nicotiana plumbaginifolia cytosolic Cu/Zn-superoxide dismutase promoter in transgenic tobacco.

Superoxide dismutases (SODs) play a key role in the cellular defense against reactive oxygen species. To study the transcriptional regulation at the cellular level, the promoter of the Nicotiana plumbaginifolia cytosolic gene encoding Cu/ZnSOD (SODCc) was fused to the beta-glucuronidase (GUS) reporter gene (gusA) and analyzed in transgenic tobacco plants. The promoter was highly active in vascular bundles of leaves and stems, where it is confined to phloem cells. In flowers, GUS activity was detected in ovules and pollen grains, in pigmented tissues of petals, and in vascular tissue of ovaries and anthers. In response to treatment with the superoxide-generating herbicide paraquat, very strong GUS staining was observed in photosynthetically active cells of leaves and in some epidermal root cells of seedlings. The expression of the SODCc-gusA was also induced in seedlings after heat shock and chilling and after treatment with sulfhydryl antioxidants such as reduced glutathione and cysteine. It is postulated that SODCc expression is directly linked to a cell-specific production of excess superoxide radicals in the cytosol.

Base Sequence↗
PubMed2000

Inhibition of calcium signaling in descending vasa recta endothelia by ANG II.

The intracellular calcium ([Ca(2+)](i)) response of outer medullary descending vasa recta (OMDVR) endothelia to ANG II was examined in fura 2-loaded vessels. Abluminal ANG II (10(-8) M) caused [Ca(2+)](i) to fall in proportion to the resting [Ca(2+)](i) (r = 0. 82) of the endothelium. ANG II (10(-8) M) also inhibited both phases of the [Ca(2+)](i) response generated by bradykinin (BK, 10(-7) M), 835 +/- 201 versus 159 +/- 30 nM (peak phase) and 169 +/- 26 versus 103 +/- 14 nM (plateau phase) (means +/- SE). Luminal ANG II reduced BK (10(-7) M)-stimulated plateau [Ca(2+)](i) from 180 +/- 40 to 134 +/- 22 nM without causing vasoconstriction. Abluminal ANG II added to the bath after luminal application further reduced [Ca(2+)](i) to 113 +/- 9 nM and constricted the vessels. After thapsigargin (TG) pretreatment, ANG II (10(-8) M) caused [Ca(2+)](i) to fall from 352 +/- 149 to 105 +/- 37 nM. This effect occurred at a threshold ANG II concentration of 10(-10) M and was maximal at 10(-8) M. ANG II inhibited both the rate of Ca(2+) entry into [Ca(2+)](i)-depleted endothelia and the rate of Mn(2+) entry into [Ca(2+)](i)-replete endothelia. In contrast, ANG II raised [Ca(2+)](i) in the medullary thick ascending limb and outer medullary collecting duct, increasing [Ca(2+)](i) from baselines of 99 +/- 33 and 53 +/- 11 to peaks of 200 +/- 47 and 65 +/- 11 nM, respectively. We conclude that OMDVR endothelia are unlikely to be the source of ANG II-stimulated NO production in the medulla but that interbundle nephrons might release Ca(2+)-dependent vasodilators to modulate vasomotor tone in vascular bundles.

Angiotensin II↗
PubMed1975

Suaeda monoica, a C(4) Plant without Typical Bundle Sheaths.

Suaeda monoica Forssk. ex J. F. Gmel was found to possess the C(4) pathway of photosynthesis. The succulent leaves of Suaeda lack a green bundle sheath formation but have a layer of chlorenchyma, containing large and centripetally arranged chloroplasts, which surrounds the water tissue. We suggest that the proximity of a chlorenchymatous cell layer to the vascular bundles is not necessary for the operation of the C(4) pathway.

Journal Article↗