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At least 289 records · Page 16Linked to original sources
PubMed2005

Arabidopsis thaliana Somatic Embryogenesis Receptor Kinase 1 protein is present in sporophytic and gametophytic cells and undergoes endocytosis.

Arabidopsis thaliana plants expressing AtSERK1 fused to yellow-fluorescent protein were generated. Fluorescence was detected predominantly at the cell periphery, most likely the plasma membrane, of cells in ovules, embryo sacs, anthers, and embryos and in seedlings. The AtSERK1 protein was detected in diverse cell types including the epidermis and the vascular bundles. In some cells, fluorescent receptors were seen in small vesicle-like compartments. After application of the fungal toxin Brefeldin A, the fluorescent receptors were rapidly internalized in the root meristem and root vascular tissue. We conclude that the AtSERK1 receptor functions in a common signalling pathway employed in both sporophytic and gametophytic cells.

Arabidopsis↗
PubMed2006

The role of ischemic preconditioning at the gracilis muscle of rats in the early phase of reperfusion injury.

PURPOSE: Verify the role of ischemic preconditioning (IPC) in ischemia and reperfusion injury on gracilis muscle of rats. METHODS: Wistar rats (n=30) were distributed in three groups, I/R and IPC groups were subdivided concerning ischemia time. A near-amputation model of the posterior limb was produced by a hip joint level incision, preserving the vascular bundle and the femur bone and ischemia was induced for 2 h and 4 h, G-I 2 h/R (n=6) and G-I 4 h/R (n=6), followed by 1 h of vascular reperfusion. The preconditioned groups, G-PCI 2 h (n=6) and G-PCI 4 h (n=6), were preceded by 3 cycles of 5 min of ischemia followed by 5 min of vascular reperfusion before sustained ischemia. In the Control Group, C-G (n=6) animals were subjected to regional approach. The analysis was done with Light Microscopy (LM). RESULTS: The levels of fibril fragmentation were progressive in the G-I 2 h/R (67% of muscle preservation) and in the G-I 4 h/R (0% of muscle preservation). However in the group of the precondition the lesion degree being in level similar to the group controls in the G-I 2 h/R (100% of muscle preservation) while at G-I 4 h/r occur less protection (67% of muscle preservation). The degree of tissue inflammatory reaction was worst at G-I 4 h/R (0% without inflammation signals) than at G-I 2 h/R (50% without inflammation signals); while in the precondition group G-IPC-2 h (83% without inflammation signals) was better than the G-IPC-4 h (67% without inflammation signals). The vascular stasis was absent only in 17% of the G-I 4 h/R and in 33% of the G-I 2 h/R. In precondition group, however, the vascular stasis was absent in 33% at G-IPC 2 h and absent in 50% at G-IPC 4 h. CONCLUSION: The IPC showed, in an earlier phase, a beneficial role at I/R derived injury on gracilis muscle of rats, as proven for the largest preservation of the fibers muscular, smaller inflammatory reaction and smaller vascular stasis.

Animals↗
PubMed1995

A family of transcripts encoding water channel proteins: tissue-specific expression in the common ice plant.

Seawater-strength salt stress of the ice plant (Mesembryanthemum crystallinum) initially results in wilting, but full turgor is restored within approximately 2 days. We are interested in a mechanistic explanation for this behavior and, as a requisite for in-depth biochemical studies, have begun to analyze gene expression changes in roots coincident with the onset of stress. cDNAs that suggested changes in mRNA amount under stress were found; their deduced amino acid sequences share homologies with proteins of the Mip (major intrinsic protein) gene family and potentially encode aquaporins. One transcript, MipB, was found only in root RNA, whereas two other transcripts, MipA and MipC, were detected in roots and leaves. Transcript levels of MipB were of low abundance. All transcripts declined initially during salt stress but later recovered to at least prestress level. The most drastic decline was in MipA and MipC transcripts. MipA mRNA distribution in roots detected by in situ hybridization indicated that the transcript was present in all cells in the root tip. In the expansion zone of the root where vascular bundles differentiate, MipA transcript amounts were most abundant in the endodermis. In older roots, which had undergone secondary growth, MipA was highly expressed in cell layers surrounding individual xylem strands. MipA was also localized in leaf vascular tissue and, in lower amounts, in mesophyll cells. Transcripts for MipB seemed to be present exclusively in the tip of the root, in a zone before and possibly coincident with the development of a vascular system. MipA- and MipB-encoded proteins expressed in Xenopus oocytes led to increased water permeability. mRNA fluctuations of the most highly expressed MipA and MipC coincided with turgor changes in leaves under stress. As the leaves regained turgor, transcript levels of these water channel proteins increased.

Amino Acid Sequence↗
PubMed2005

Bone flap prefabrication: an experimental study in rabbits.

The usual method to prefabricate a bone flap is to harvest a nonvascularized bone graft and to implant the artery and vein bundle between segments of bone graft. The basic problem of this method is sacrificing an artery for prefabrication. Another method for creating flap donor sites without using an artery is venous flap prefabrication. There are a few articles describing bone flap prefabrication, and these include implantation of both artery and vein as a vascular bundle. Also, there is no experimental study in the literature using a vein or an arterialized vein pedicle for bone flap prefabrication. As an experimental model for bone flap prefabrication, the rabbit ear vascular model was chosen. For the experiments 3 groups were formed. Each group contained 5 rabbits. In the first experimental group a vein was implanted between the halves of bone graft. In the second experimental group an arterialized vein was implanted between the halves of bone graft. To compare the viability of the bone graft of the 2 prefabrication groups, a bone graft was implanted into the subcutaneous pocket of the posterior auricular area in the third group. The authors examined 5 rabbits in each group by microangiography at the end of 6 weeks except for group 3. On microangiographic analysis, groups 1 and 2 showed patency of the vascular pedicle. There was no difference between these 2 groups from the point of view of vascular patency and bone appearance. Bone scintigraphy was performed for 5 rabbits in each group. On bone scintigraphic scans, the bone component of the flaps was visualized in groups 1 and 2, but not in group 3. A quantitative analysis of images was performed by drawing symmetric spherical regions of interest (ROIs) over both the implanted area and cranial bone. The uptake ratios were computed by dividing the mean counts in the implanted ROI by mean counts in the cranial bone ROI. The mean value was 0.86 +/- 0.02 in group 1 and 0.86 +/- 0.04 in group 2. A statistically significant uptake difference was not seen between venous and arterialized venous groups (P < 0.01). Histologic examination was performed all rabbits in each group, and demonstrated that the bony component was viable, showing osteocytes containing lacunae, osteoblasts along bony trabeculae, and vascular channels in groups 1 and 2. In group 3, the bony architecture of the graft was still apparent, but all bone within it was dead. There were no significant microangiographic, histologic, and scintigraphic differences between the 2 experimental methods.

Angiography↗
PubMed1988

Three-dimensional analysis of the arterial pattern of the upper limbs in Lorisiformes (Prosimiae, Primates).

A study of the arterial patterns of the upper limbs in Lorisiformes (Prosimiae), especially those of the rete mirabile and their correlating arteries, was carried out by three-dimensional arteriographic analysis. The rete displayed at least two types of plexiform distribution: (1) a vascular bundle in Lorisidae, which consists of a division of the main artery into a principal trunk surrounded upwards by about 50 small arteries, and (2) a simple network pattern in Galagidae, which, at most, is composed of simple vascular networks of the nature of a few widely scattered anastomoses. The arterial patterns of the upper limb in Lorisiformes are basically the same, but the position of divergence and the number and size of the vessels in the rete differ. The arterial patterns of the upper limbs in Lorisiformes closely resemble the development of the vessels in the 21- to 23-mm stages of human embryonic growth. In this study, we observed some similarity in the patterns between the rete mirabile and the superficial brachial artery in man.

Angiography↗
PubMed1989

[Changes in the microvascular patterns during the osseous healing of the tooth extraction wounds].

Successive changes in the vascular pattern during the osseous healing of extraction wounds were investigated by studying microvascular casts under a scanning electron microscope. The casts were prepared utilizing the plastic injection method, after the extraction of the upper four incisors of the Japanese monkey (Macaca fuscata). Five days after extraction, vascular buds have sprouted from a pre-existing blood vessel on the alveolar wall into the blood clot, and leakage of the plastic injected was found from the tips of these buds. One week after extraction, newly-formed vessels have extended widely to the socket center, and dilated vessels have arborized towards the socket opening. Two weeks after extraction, the socket was filled with thick, newly-formed vessels. In the socket fundus, the woven bone was formed between irregular vascular networks, but was arranged different in the socket wall. Four weeks after extraction, the new bone forming on the socket wall became thickened and converted to a lamella-like bone. Inside it the woven bone was raised from the fundus, and blood vessels leaving it were decreased in their thickness and passed toward the socket center. Five weeks after extraction, the new bone structures came up to the level of the socket opening, the surface of which appeared as a shallow concavity (pivot), from which vascular bundles were directed to the socket opening. A beginning of the bone-remodeling was seen in osseous trabeculae in the socket fundus. Six weeks after extraction, almost all of the socket became filled with new trabeculae, between which, fine vascular networks were sorted out and communicated with the periosteal vascular network beyond the socket margin. The interalveolar septum between the extraction sockets was thickened by deposition of the lamella-like bone to be remodeled to a cancellous bone. It can be said that microvascular patterns formed through all stages of the osseous healing of the extraction wounds contributed to a woven bone formation and its development.

Alveolar Process↗
PubMed1990

[Vascularized tissue complexes from the region of the radial artery in plastic surgery of the arm].

Based upon results of topographo-anatomical research and personal experiences with transplantation of 91 tissue complexes on radial vascular bundle the authors made an attempt to systematize the available data concerning this source of tissues. The substantiation of using the tissue complexes consisting of several fascio-cutaneous (fascio-cutaneous and muscular) flaps at different levels of the vascular pedicle as well as superlong deltoid-radial flap on two vascular pedicles are first given.

Arm Injuries↗
PubMed1990

Role of free vascularized bone grafts in the experimentally-induced ischemic necrosis of the femoral head.

In 15 mongrel adult dogs, an ischemic necrosis of the femoral head was produced, following the technique described by Gartsman and colleagues. Five weeks later, a 6- to 8-cm long rib graft was harvested with its vascular bundle and transferred into the previously induced ischemic femoral head. Microsurgical anastomoses were performed for revascularizing the rib graft. Dogs were studied using scintigraphy, blood flow measurements, roentgenograms, angiograms, and histology at four, eight and 12 weeks after grafting. New bone and vascular formation was exhibited throughout the study, as demonstrated by a highly positive scintigraphic activity and the formation of numerous arterial terminal branches arising from the rib graft circulation which entered the femoral head and reached the subchondral plate. The formerly necrotic femoral head bone exhibited osteoblastic activity, viable osteocytes, and well-populated bone marrow. The rib graft was also incorporated into the femoral head. These results suggest that a vascularized bone graft is able to repair a femoral head necrosis, and may be considered a rational approach for clinical purposes.

Anastomosis, Surgical↗
PubMed1990

[Comparative characteristics of the forearm and crus as donor sites for obtaining composite skin flaps on vascular pedicles].

The ++topographo-anatomical investigations on 67 forearms and 58 crura permitted to establish the possibility for formation of the free similar types of island composite cutaneous flaps on the large vascular bundles. On the crus, the possibility to elevate two more types of the island cutaneous flaps without transection of the major vessels is substantiated. The variants of microsurgical autotransplantation and trasplantation+ of the composite cutaneous flaps of the forearm and crus on the vascular pedicles are discussed.

Arm Injuries↗
PubMed2002

The anatomy and chemistry of the colour bands of grasstree stems (Xanthorrhoea preissii) used for plant age and fire history determination.

A new method of ageing and determining the fire history of grasstrees, based on colour bands running along the stem, has been developed. As part of our evaluation of the technique, we examined the structural and chemical basis of the colour differences. Exposed ends of the leaf bases are cream, brown and black, with the inner cortex, especially in the black leaf bases, being darker than the outer cortex. There was no structural difference between the three leaf base types. Tannin concentration increased from cream to brown to black leaf bases, and from the inner to outer cortex, and remained quite stable over many years. Both water-soluble and insoluble pigments contribute to the darkness of the black leaf bases. A hydrophobic naphthoquinone was present in the conducting tissues of the vascular bundles, and related naphthalene-derivatives were present in the surrounding tissues. We conclude that the colour differences between the leaf bases have a chemical basis that can be linked to environmental changes: tannin cells to phenological effects, and naphthalene-derivatives in the vascular core to the passage of fire.

Chromatography, Gas↗
PubMed2003

Laser-capture microdissection, a tool for the global analysis of gene expression in specific plant cell types: identification of genes expressed differentially in epidermal cells or vascular tissues of maize.

Laser-capture microdissection (LCM) allows for the one-step procurement of large homogeneous populations of cells from tissue sections. In mammals, LCM has been used to conduct cDNA microarray and proteomics studies on specific cell types. However, LCM has not been applied to plant cells, most likely because plant cell walls make it difficult to separate target cells from surrounding cells and because ice crystals can form in the air spaces between cells when preparing frozen sections. By fixing tissues, using a cryoprotectant before freezing, and using an adhesive-coated slide system, it was possible to capture large numbers (>10,000) of epidermal cells and vascular tissues (vascular bundles and bundle sheath cells) from ethanol:acetic acid-fixed coleoptiles of maize. RNA extracted from these cells was amplified with T7 RNA polymerase and used to hybridize a microarray containing approximately 8800 maize cDNAs. Approximately 250 of these were expressed preferentially in epidermal cells or vascular tissues. These results demonstrate that the combination of LCM and microarrays makes it feasible to conduct high-resolution global gene expression analyses of plants. This approach has the potential to enhance our understanding of diverse plant cell type-specific biological processes.

Aquaporins↗
PubMed1995

Convective uphill transport of NaCl from ascending thin limb of loop of Henle.

In this paper we describe a mathematical model of the renal inner medulla based on a previously proposed model [A.S. Wexler, R.E. Kalaba, and D.J. Marsh. Am. J. Physiol. 260 (Renal Fluid Electrolyte Physiol. 29): F368-F383, 1991] in which in the inner medullary ascending thin limb of Henle's loop (ATL) and collecting duct (CD) exchange with a local capillary node with the reabsorbed water and solutes flowing radially toward a central vascular bundle. Our model differs in that ascending and descending vasa recta and surrounding interstitial space are replaced by a central core. Our analysis of the coupled ATL-CD system shows that it is theoretically capable of transporting NaCl out of the ATL into the central vascular space (approximated by the central core) against a concentration gradient, which in the absence of radial diffusion can be arbitrarily large. By numerical solution of the model with the radial diffusion coefficient (D(r)) for NaCl of 0, we find that the ATL can be more than 100 mosmol/l hypotonic with respect to the core. We also find that with restricted diffusion the osmolality of the CD at the papilla is significantly greater than that of the loop of Henle. As D(r) approaches the diffusion coefficient of NaCl in free solution, the osmolality of the loop increases and that of the CD decreases. Thus, overall, contrary to intuitive expectations, the radial separation and uphill transport of NaCl do not give any significant increase in loop concentration, which depends primarily on the quantity of urea reabsorbed from the CD.

Animals↗
PubMed1994

Expression of an auxin- and cytokinin-regulated gene in cambial region in Zinnia.

The expression patterns of a cDNA clone, p48h-10, of an auxin-induced gene were examined in isolated mesophyll cells of Zinnia and in the organs of Zinnia plants. In the isolated mesophyll cells, the mRNA accumulates in 48 hr of culture with 1-naphthaleneacetic acid alone. Because the first cell division occurs before 36 hr of culture, the gene probably is not involved in cell division. Benzyladenine does not induce expression of this gene, but the combination of 1-naphthaleneacetic acid and benzyladenine induces the mRNA accumulation about 24 hr earlier than does 1-naphthaleneacetic acid alone. Tissue print hybridization shows that the mRNA is present predominantly in the cambial region in stems, leaves, and roots and in the vascular bundles in flower buds but does not occur in the apical regions of shoot or root. The characteristics of the gene expression, including auxin- and cytokinin-regulated induction and cambial region localization, encourage us to suggest that the gene is involved in the early process of vascular differentiation.

Journal Article↗
PubMed2005

[Transobturator surgery for female urinary continence: from outside to inside or from inside to outside: a comparative anatomic study].

OBJECTIVE: Transobturator route is now largely used for the positioning of the supporting sub uretral tape in the surgical treatment of female urinary incontinence. This operation can be done using the original technique from the outside to the inside or by inside to outside. Our anatomic study evaluates the specific dangers of each MATERIAL AND METHODS: Our study is based on the dissection of seven fresh bodies, therefore 14 obturator regions. The dissections were done after the positioning of the tape from outside to inside on one side and inside to outside on the other side. We particularly studied the distances separating the tape from the inferior pudendal vascular bundle and the posterior branch of the obturator nerve. RESULTS: With the inside - outside technique there is a greater proximity between the path of the tape and the studied structures, therefore the risk of damage is greater. CONCLUSIONS: The two techniques are not equivalent. There are less vascular and neurological risk using the original outside to inside technique.

Cadaver↗
PubMed1985

Mode of neural control mediating rat tail vasodilation during heating.

The purpose of this investigation was to delineate the mode of efferent neural control mediating rat tail vasodilation during body heating. Tail blood flow (venous occlusion plethysmography), tail skin temperature over the ventral vascular bundle, and arterial pressure were measured in Sprague-Dawley rats anesthetized with pentobarbital sodium (45 mg/kg). Three protocols were followed: anesthesia of the lumbar sympathetic chain, bilateral lumbar sympathectomy, and sympathetic nerve stimulation during varying degrees of alpha-adrenergic receptor blockade. Mean tail blood flow and tail vascular conductance (TVC) during body heating were 40.3 +/- 8.7 ml X 100 ml-1 X min-1 and 39.2 +/- 9.2 ml X 100 ml-1 X min-1 X 100 mmHg-1, respectively. Interruption of sympathetic nerve activity by sympathetic nerve anesthetization or sympathectomy during heat stress caused a nonsignificant increase in TVC to 112.7 +/- 1.8 and 121.12 +/- 6.3%, respectively, of the values achieved with body heating. Sympathectomy performed in normothermic animals that had recovered from prior heating caused an increase in TVC to 128.4 +/- 14.0% of the levels achieved during the previous heating period. In addition, sympathetic nerve stimulation after complete alpha-adrenergic receptor blockade failed to produce a vasodilation [control TVC = 10.2 +/- 3.9 vs. TVC during nerve stimulation = 10.4 +/- 3.9 (P greater than 0.05)]. It is concluded that the increase in TVC during body heating occurs solely via a reduction in vasoconstrictor nerve activity.

Animals↗
PubMed2003

Radial patterning of Arabidopsis shoots by class III HD-ZIP and KANADI genes.

BACKGROUND: Shoots of all land plants have a radial pattern that can be considered to have an adaxial (central)-abaxial (peripheral) polarity. In Arabidopsis, gain-of-function alleles of PHAVOLUTA and PHABULOSA, members of the class III HD-ZIP gene family, result in adaxialization of lateral organs. Conversely, loss-of-function alleles of the KANADI genes cause an adaxialization of lateral organs. Thus, the class III HD-ZIP and KANADI genes comprise a genetic system that patterns abaxial-adaxial polarity in lateral organs produced from the apical meristem. RESULTS: We show that gain-of-function alleles of REVOLUTA, another member of the class III HD-ZIP gene family, are characterized by adaxialized lateral organs and alterations in the radial patterning of vascular bundles in the stem. The gain-of-function phenotype can be obtained by changing only the REVOLUTA mRNA sequence and without changing the protein sequence; this finding indicates that this phenotype is likely mediated through an interference with microRNA binding. Loss of KANADI activity results in similar alterations in vascular patterning as compared to REVOLUTA gain-of-function alleles. Simultaneous loss-of-function of PHABULOSA, PHAVOLUTA, and REVOLUTA abaxializes cotyledons, abolishes the formation of the primary apical meristem, and in severe cases, eliminates bilateral symmetry; these phenotypes implicate these three genes in radial patterning of both embryonic and postembryonic growth. CONCLUSIONS: Based on complementary vascular and leaf phenotypes of class III HD-ZIP and KANADI mutants, we propose that a common genetic program dependent upon miRNAs governs adaxial-abaxial patterning of leaves and radial patterning of stems in the angiosperm shoot. This finding implies that a common patterning mechanism is shared between apical and vascular meristems.

Arabidopsis↗
PubMed2003

Dental radiographic features of impacted third molars and some management implications.

The objective of the study was to determine the principal dental radiographic features of impacted third molars and to highlight some management implications, 255 periapical radiographs belonging to 197 patients with the clinical records were examined. The age of the subjects, sex, and degree of impaction, inclination, depth, mesiodistal space and associated pathology were documented as well as the number of roots and their relationship to the neurovascular bundle. The mean age was 23.4 years with more female teeth (152, 59.6%) than male (103, 40.4%). Majority were partially erupted (223, 91.4%) with vertical impaction most commonly seen in 80 teeth (31.4%). Over half of the teeth (135, 52.9%) had no obvious relationship with the inferior alveolar neuro-vascular bundle and where this existed, darkening of the root was the most common radiographic indicator (55 teeth, 21.6%). Most of the teeth (54.9%) had no obvious pathologic changes associated. In those with pathologic changes, periodontal bone loss and a wide follicle were most commonly observed (44 teeth or 17.3% in both cases). Older subjects had significantly more periodontal bone loss (p = 0.001). Periapical radiographic examination can reveal vital information for treatment planning of impacted teeth and the monitoring of asymptomatic teeth.

Adolescent↗
PubMed1979

[An experimental study on repair and restoration of gliding function of the injured flexor tendon of the finger. Part 6: A mode of vascularization of the grafted tendon within the pseudosheath (author's transl)].

The so-called two-stage procedure has been used in the reconstructive surgery for the severely injured flexor tendon of the finger. However, only little has been known as to vascularity of the grafted tendon within the pseudosheath. In order to clarify this problem, a series of experimental studies were carried out using young chickens. First, the flexor tendon of the fourth digit of chicken with its sheath was replaced by a silicone rod. The distal end of the rod was sutured to the stump of the flexor digitorum profundus and the proximal end left free. Then, in ten to sixteen weeks, upon removal of the rod, the flexor digitorum profundus of the third digit was grafted through into the newly formed pseudosheath. The paw was immobilized with plaster case in moderate flexion for three weeks, then the chicken was allowed to walk freely. At the different time intervals, starting from the third day to the fifteen weeks after surgery, a mode of vascularization of the grafted tendon and its surrounding tissue was examined microangiographically. The vessels appear at the area of proximal and distal stump of the grafted tendon a week postoperatively, and additional vessels appear at the contact area of the pseudosheath and the grafted tendon two weeks postoperatively. These vessels formed mutual anastomosis in five to six weeks. With time, the vessels connecting between the epitenon and the pseudosheath gradually enlarge and assemble together to form vascular bundles, so that the appearance of the structure becomes similar to that of the mesotenon. Three weeks postoperatively, the vessels appeared in the grafted tendon, and grew gradually so that these vessels ran through the full length of the grafted tendon in five to six weeks. About ten weeks, the vascularity of the grafted tendon is more abundant than that of the normal tendon, but diminished gradually so as to resemble that of the normal tendon at the fifteeth week. Thus, the growth of the vessels of the tendon grafted by two-stage procedure is delayed by two weeks compared with that by the primary tendon grafting.

Animals↗