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At least 865 records · Page 48Linked to original sources
PubMed1993

Recurrent pyogenic granulomas: a form of lobular capillary hemangioma.

Two cases of pyogenic granuloma recurred despite what was originally thought to be a sufficient surgical excision. The granulomas presented clinically as polypoid structures, one on the finger and one on the chin. On histologic examination, all showed polypoid configuration with lobules of small vessels and endothelial cell proliferation. The recurrent lesions also showed similar lobules, but interspersed between the collagen bundles in the deeper dermis. Vascular tumors such as the lobular pyogenic granulomas, intravenous capillary hemangiomas, and acquired tufted angiomas were compared to our tumors.

Chin↗
PubMed1998

Bundle sheath cells and cell-specific plastid development in Arabidopsis leaves.

Bundle sheath cells form a sheath around the entire vascular tissue in Arabidopsis leaves and constitute a distinct leaf cell type, as defined by their elongate morphology, their position adjacent to the vein and by differences in their chloroplast development compared to mesophyll cells. They constitute about 15% of chloroplast-containing cells in the leaf. In order to identify genes which play a role in the differential development of bundle sheath and mesophyll cell chloroplasts, a screen of reticulate leaf mutants of Arabidopsis was used to identify a new class of mutants termed dov (differential development of vascular-associated cells). The dov1 mutant clearly demonstrates a cell-specific difference in chloroplast development. Mutant leaves are highly reticulate with a green vascular pattern. The underlying bundle sheath cells always contain normal chloroplasts, whereas chloroplasts in mesophyll cells are abnormal, reduced in number per cell and seriously perturbed in morphology at the ultrastructural level. This demonstrates that differential chloroplast development occurs between the bundle sheath and mesophyll cells in the Arabidopsis leaf.

Arabidopsis↗
PubMed1990

Elastin in human, baboon, and mouse liver: an immunohistochemical and immunoelectron microscopic study.

Light microscope histochemistry and immunohistochemistry, and routine electron microscopy techniques were performed to analyse elastin distribution and structure in the human liver compared with that in baboon and mouse. In man and baboon, elastic fibers stained by iron hematoxylin or orcinolnew fuchsin seemed to be solitary and were few in number; in the mouse they were thinner but abundant, both in the portal tract and in hepatic veins. Orcein or resorcin-fuchsin stains, employed after oxidation of tissue sections, revealed a network comprising elastic, elaunin, and oxytalan fibers, which was also demonstrated by immunofluorescence with anti-elastin antibody in man and baboon. At the ultrastructural level, the elastic fibers of the human portal tract corresponded to discontinuous patches of amorphous material intermingled with few microfibrils. These contrasted with the thinner elastic fibers of baboon and mouse liver which had a core of amorphous material. In man and baboon, these fibers meshed into slender bundles of microfibrils often exhibiting small spots of amorphous material (elaunin fibers) and terminated as isolated microfibrils (oxytalan fibers). Immunoelectron microscopy of elastin carried out on baboon liver tissue labelled the amorphous material and also its microfibrillar component. Immunoperoxidase deposits were also associated with isolated bundles of microfibrils in the baboon portal stroma. Immunolabelling and elastic stains disclosed an important elastin portal network located around vascular, biliary structures and interspaced with collagen bundles. The structural polymorphism of elastin, assembling different relative amounts of amorphous material and microfibrils, might have a relationship with the required elasticity in a given species.

Adult↗
PubMed1979

Distribution of Photosynthetic Enzymes between Mesophyll, Specialized Parenchyma and Bundle Sheath Cells of Arundinella hirta.

Arundinella hirta L. is a C(4) plant having an unusual C(4) leaf anatomy. Besides mesophyll and bundle sheath cells, A. hirta leaves have specialized parenchyma cells which look morphologically like bundle sheath cells but which lack vascular connections and are located between veins, running parallel to them. Activities of phosphoenolpyruvate and ribulose-1,5-bisphosphate carboxylases and phosphoenolpyruvate carboxykinase, NADP-and NAD-malic enzymes were determined for whole leaf extracts and isolated mesophyll protoplasts, specialized parenchyma cells, and bundle sheath cells. The data indicate that A. hirta is a NADP-malic enzyme type C(4) species. In addition, specialized parenchyma cells and bundle sheath cells are enzymatically alike. Compartmentation of enzymes followed the C(4) pattern with phosphoenolpyruvate carboxylase being restricted to mesophyll cells while ribulose-1,5-bisphosphate carboxylase and decarboxylating enzymes were restricted to bundle sheath and specialized parenchyma cells.

Journal Article↗
PubMed2004

Ocular manifestations of dengue fever.

PURPOSE: To evaluate ocular manifestations associated with dengue fever. DESIGN: Retrospective case series and literature review. METHODS: Clinical records of patients with dengue fever who subsequently had ocular symptoms and signs develop were reviewed. The clinical presentation and ocular complications were evaluated. RESULTS: Six patients, 5 females and 1 male, were seen with a sudden decrease in vision 6 to 7 days after the initial manifestations of dengue fever were identified. The diagnosis was confirmed by detection of dengue-specific IgM antibodies (IgM enzyme-linked immunoassay). The presenting best-corrected visual acuity ranged from 20/30 to counting fingers, and ocular involvement was bilateral but asymmetric in 5 cases and unilateral in 1 case. Fundus findings included small, intraretinal, whitish lesions, with localized retinal and retinal pigment epithelium (RPE) disturbance, small dot hemorrhages, and vascular sheathing around the macula and the papillomacular bundle. Fluorescein angiography showed arteriolar focal knobby hyperfluorescence at the macula with mild staining of the vascular walls and leakage at the level of the RPE. All 5 cases that had indocyanine green angiography done showed early diffuse choroidal hyperfluorescence with late silhouetting of the larger choroidal vessels. Five patients received steroid therapy: 1 topical, 2 periocular, and 2 oral. Over 2 to 4 months, RPE discoloration was observed over the affected areas. After the acute episode, 3 patients showed partial recovery of vision, and in the remaining patients, the visual acuity remained stable. CONCLUSIONS: Ocular complications associated with dengue fever are rare but may result in permanent visual impairment.

Adult↗
PubMed1978

Nerve fiber layer astrocytes of the primate retina: morphology, distribution, and density.

The nerve fiber layer of several species of primate has been studied with Golgi silver impregnations and Nissl stains. The morphology, distribution, and density of fibrous astrocytes of the nerve fiber layer are described. Two classes of astrocytes are distinguished: elongated cells whose processes parallel the nerve fiber bundles and cover a rectangular area more than two time longer than wide without vascular contact and stellate cells whose processes conspicuously cross the nerve fiber bundles to cover a slightly oval area and make unspecialized vascular contacts. The density of glial nuclei in the nerve fiber layer is roughly proportional to the thickness of the layer all across the retina, so that higher densities are seen in specialized regions such as the arcuate nerve fiber bundles and near the optic disc.

Animals↗
PubMed2004

Restricted inactivation of serum response factor to the cardiovascular system.

Serum response factor (SRF) directs programs of gene expression linked to growth and muscle differentiation. To investigate the role of SRF in cardiovascular development, we generated mice in which SRF is knocked out in >80% of cardiomyocytes and >50% of vascular smooth muscle cells (SMC) through SM22alpha-Cre-mediated excision of SRF's promoter and first exon. Mutant mice display vascular patterning, cardiac looping, and SRF-dependent gene expression through embryonic day (e)9.5. At e10.5, attenuation in cardiac trabeculation and compact layer expansion is noted, with an attendant decrease in vascular SMC recruitment to the dorsal aorta. Ultrastructurally, cardiac sarcomeres and Z disks are highly disorganized in mutant embryos. Moreover, SRF mutant mice exhibit vascular SMC lacking organizing actin/intermediate filament bundles. These structural defects in the heart and vasculature coincide with decreases in SRF-dependent gene expression, such that by e11.5, when mutant embryos succumb to death, no SRF-dependent mRNA expression is evident. These results suggest a vital role for SRF in contractile/cytoskeletal architecture necessary for the proper assembly and function of cardiomyocytes and vascular SMC.

Animals↗
PubMed2005

Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells.

Stress fibers (SFs), a contractile bundle of actin filaments, play a critical role in mechanotransduction in adherent cells; yet, the mechanical properties of SFs are poorly understood. Here, we measured tensile properties of single SFs by in vitro manipulation with cantilevers. SFs were isolated from cultured vascular smooth muscle cells with a combination of low ionic-strength extraction and detergent extraction and were stretched until breaking. The breaking force and the Young's modulus (assuming that SFs were isotropic) were, on average, 377 nN and 1.45 MPa, which were approximately 600-fold greater and three orders of magnitude lower, respectively, than those of actin filaments reported previously. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length in an ATP-independent manner after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN, which was comparable with the traction force level applied by adherent cells at single adhesion sites to maintain cell integrity. These results suggest that SFs can bear intracellular stresses that may affect overall cell mechanical properties and will impact interpretation of intracellular stress distribution and force-transmission mechanism in adherent cells.

Actinin↗
PubMed1992

Organization of the optic chiasm in the hatched chick.

In the hatched chick the fibers of the two optic nerves segregate into clearly defined bundles when they cross to the other side. These bundles run in horizontally oriented tiers. The tiers are demarcated by blood vessels and pial tissue. The organization of these tiers was investigated qualitatively and quantitatively using light and electron microscopy as well as tracer techniques. The fibers within the tiers cross to the contralateral optic tract without leaving their respective tier. The mean total number of tiers is 34 with a great individual variation. A preference in the superposition of one side over the other could not be observed. Comparing these data with our earlier study (Rager et al.: Anat. Embryol., 179:135-148, 1988) it can be concluded that neither the segregation of fibers into discrete bundles nor the variability in the number of alternating tiers seem to disturb the topography of fibers as it is achieved in the optic nerve. The pattern of vascularization correlates with the order of crossing axon bundles and contributes to the demarcation of the tiers. The chiasm is vascularized by the Aa. preopticae and the A. infundibularis.

Animals↗
PubMed1999

Collagen fiber arrangement in canine hepatic venules.

Cell-maceration/scanning electron microscopy, serial sections and scanning electron microscopy of vascular resin casts were employed to demonstrate the arrangement of collagen fibers in the terminal hepatic venules, involving the central, intercalated and collecting veins in dog liver. In cell-maceration specimens, each collagen fiber was observed to run in various directions, forming a sheath with a compact meshwork of collagen fibers. The collagenous meshwork in the hepatic venules was looser than those of the terminal portal venules and hepatic arterioles. Some collagen fibers formed bundles with an elongated spiral arrangement encircling the wall of the terminal hepatic venules. In resin casts, these venules were observed as a twisted configuration caused by spiral collagen bundles. A helical modification of such connective tissue bundles might provide a mechanically stable vascular structure and permit reversible changes in linear and circumferential vascular dimensions at the terminal tributaries of veins. Round or oval pores with diameters of approximately 9 microns were also observed in the sheath of collagen fibers. These pores, together with the relatively loose collagenous meshwork in the hepatic venules, might play a role in lymphocyte migration from these venules into the surrounding tissue and provide high permeability to the venule walls. No such helical configuration and pores were observed in either the portal venules or the hepatic arterioles.

Animals↗
PubMed1999

Fine-needle aspiration cytologic features of pseudovascular adenoid squamous-cell carcinoma of the lung.

Pseudovascular adenoid squamous-cell carcinoma (PASCC) is an epithelial malignancy with spindle-cell features that can mimic vascular neoplasms, particularly angiosarcoma, in its morphologic characteristics. There have been only a few surgical pathology reports of PASCC arising in the lung, skin, and breast. We describe the fine-needle aspiration (FNA) cytologic and histologic features of a pulmonary PASCC in a 66-yr-old man. The aspiration yielded individually scattered and syncytial fragments of malignant epithelioid-appearing cells with oval to spindle shapes, prominent nucleoli, and a finely vacuolated amphophilic cytoplasm. The core needle biopsy specimen displayed these same cells lining pseudoluminal spaces, with intervening bundles of fibroconnective tissue simulating a vascular neoplasm. The neoplastic cells stained positively with cytokeratin (AE-1/3), epithelial membrane antigen, and vimentin and were nonreactive with S-100, muscle-specific actin, CD31, CD34, and carcinoembryonic antigen. These cytologic, histologic, and immunocytochemical features supported a diagnosis of PASCC. To the best of our knowledge, this is the first report of the FNA cytologic features of this pseudovascular variant of adenoid squamous-cell carcinoma. This FNA case illustrates that the cytologic impression was more accurate and, in fact, that the histologic features of PASCC can be misleading. The correct identification of PASCC and its distinction from angiosarcoma has important clinical ramifications for treatment and prognosis. FNA cytologic examination with ancillary studies is a minimally invasive procedure that can distinguish PASCC from sarcomatous lesions. Diagn. Cytopathol. 1999;21:265-270.

Aged↗
PubMed2006

Estrogen induces angiogenesis of the female rabbit bladder.

Postmenopausal bladder dysfunction has been speculated to involve decreased circulating estrogen levels. It is our hypothesis that estrogen induces bladder dysfunctions by modulating blood flow to the bladder, i.e. low estrogen reduces blood flow to the bladder, whereas high estrogen increases blood flow. Our previous studies have demonstrated that estrogen administration in female rabbits induces a 'functional hypertrophy' of the urinary bladder smooth muscle represented by increased smooth muscle mass, which corresponds to increased contractile responses to all forms of stimulation. The present study investigates the effect of estrogen on vasculature density and distribution. Twenty-four female New Zealand white rabbits were separated into six groups of four rabbits each. Group 1 served as controls. Groups 2-6 were ovariectomized. Two weeks after ovariectomy (Ovx), groups 3-6 were given 17-beta estradiol (1 mg/kg per day) by s.c. implant for 1, 3, 7, and 14 days respectively. Blood vessel density and distribution were evaluated by immunohistochemistry and quantitative image analyses. Ovx resulted in significant vascular degeneration and decreased density, whereas estradiol administration mediated a significant angiogenic effect characterized by increased vascular density, and distribution of new vasculature within the smooth muscle bundles of the detrusor. Estradiol-induced vasculogenesis corresponds with our previously demonstrated increase in blood flow to the bladder and increased contractility. The most interesting aspect of these studies is the increased vascularization localized within the muscle bundles rather than between the muscle bundles, which may be important in the link between estrogen and increased incidence of cancers.

Animals↗
PubMed2004

Evaluation of the paratrend multi-analyte sensor for potential utilization in long-duration automated cell culture monitoring.

BACKGROUND: Compact and automated sensors are desired for assessing the health of cell cultures in biotechnology experiments. While several single-analyte sensors exist to measure culture health, a multi-analyte sensor would simplify the cell culture system. One such multi-analyte sensor, the Paratrend 7 manufactured by Diametrics Medical, consists of three optical fibers for measuring pH, dissolved carbon dioxide (pCO(2)), dissolved oxygen (pO(2)), and a thermocouple to measure temperature. The sensor bundle was designed for intra-vascular measurements in clinical settings, and can be used in bioreactors operated both on the ground and in NASA's Space Shuttle and International Space Station (ISS) experiments. METHODS: A Paratrend 7 sensor was placed at the outlet of a bioreactor inoculated with BHK-21 (baby hamster kidney) cells. The pH, pCO(2), pO(2), and temperature data were transferred continuously to an external computer. Cell culture medium, manually extracted from the bioreactor through a sampling port, was also assayed using a bench top blood gas analyzer (BGA). RESULTS: Two Paratrend 7 sensors were used over a single cell culture experiment (64 days). When compared to the manually obtained BGA samples, the sensor had good agreement for pH, pCO(2), and pO(2) with bias (and precision) 0.005(0.024), 8.0 mmHg (4.4 mmHg), and 11 mmHg (17 mmHg), respectively for the first two sensors. A third Paratrend sensor (operated for 141 days) had similar agreement (0.02+/-0.15 for pH, -4+/-8 mm Hg for pCO(2), and 24+/-18 mmHg for pO(2)). CONCLUSION: The resulting biases and precisions are com- parable to Paratrend sensor clinical results. Although the pO(2) differences may be acceptable for clinically relevant measurement ranges, the O(2) sensor in this bundle may not be reliable enough for the ranges of pO(2) in these cell culture studies without periodic calibration.

Animals↗
PubMed1992

The split rib bundle graft in mandibular reconstruction.

This article describes a modified technique for the use of free non-vascularized split ribs (bound together in the form of a tight bundle), to reconstruct different types of mandibular defects. Experience gained over the last 4 years in treating 38 patients with different pathological lesions is presented. The procedure, carried out simultaneously with bone resection proved to be highly effective in providing mesio-distal spanning of the defect, adequate mandibular height as well as bucco-lingual thickness. This technique utilizes the different theories of osteogenesis: (a) from the periosteal cells, (b) from the transplanted living osteocytes and from (c) stimulating host mesenchymal cells to form new bone by bone induction. The surgical technique, results and conclusions are presented in this report.

Adolescent↗
PubMed1979

The meatally based musculoperiosteal flap in cavity obliteration.

A meatally based musculoperiosteal flap that was formed for radical mastoid cavity obliteration was deliberately excised during revision surgery in three cases of recurring tympanic cholesteatoma. The flaps, which contained subcutaneous connective tissue, were well vascularized and contained large, viable muscle bundles and many nerve trunks from the postauricular branch of the facial nerve. In two cases, the periosteum-attached bone chips that had been removed from the patient's mastoid tip region and implanted to form a new bony canal wall were viable and gave the intended support for the meatus after radical ear surgery.

Adolescent↗
PubMed2005

Metastatic solid-pseudopapillary tumour of the pancreas: clinico-biological correlates and management.

Solid-pseudopapillary tumour of the pancreas is a rare neoplasm of young women, currently categorised in the World Health Organization classification under exocrine pancreatic tumours. Increased awareness of this condition correlated recently with an apparent rise in incidence as well as recognition of more aggressive clinical courses. We describe two patients with solid-pseudopapillary tumour of the pancreas. A smaller, localised tumour in an unusually young white man was surgically excised with no evidence of recurrence after 2 years. The other case also had an uncommon presentation, with an aggressive course resulting in vascular encasement of the superior mesenteric bundle and aorta, and local involvement of the mesenteric lymph nodes. A literature review was carried out, and the main clinico-pathological features and strategies of treatment of solid-pseudopapillary tumour of the pancreas are presented. Pathological, genetic and molecular features distinguish solid-pseudopapillary tumours from pancreatic ductal adenocarcinoma. Furthermore, neuroendocrine differentiation can be found focally in occasional cases of solid-pseudopapillary tumour. Patients with localised disease are usually cured by surgery. Prolonged survival can be seen in the presence of distant metastasis, if such lesions are resected surgically. Chemotherapy and radiation therapy are used in rare cases when resection is not possible. No current chemotherapy regimens are considered standard in the treatment of this tumour. A rational chemotherapy protocol for such a rare tumour needs to consider its origin and clinical behaviour. However, the indolent clinical progression of solid-pseudopapillary tumours is similar to that of pancreatic neuroendocrine tumour.

Adult↗
PubMed1999

Nitrous acid pretreatment of tendon xenografts cross-linked with glutaraldehyde and sterilized with gamma irradiation.

Collagenous xenografts made from kangaroo tail tendon cross-linked with glutaraldehyde have a potential application in the reconstruction of massive digital tendon deficits. However, a limitation to the clinical use of these xenografts has been the optimization of collagen cross-linking, and subsequent bio-incorporation and retention of mechanical properties following implantation. The purpose of this study was to evaluate the effect of nitrous acid on modulating the biologic and mechanical properties of tendon xenografts cross-linked with glutaraldehyde. Tendon xenografts were pretreated with 0.1 or 0.01 M nitrous acid solution, prior to cross-linking in 2% glutaraldehyde and sterilization by gamma irradiation. Xenografts were implanted intramuscularly in rabbits to examine biocompatability, and also used to repair ovine digital extensor tendon deficits to evaluate functional incorporation. Histologically, intramuscularly implanted nitrous acid pretreated xenografts in rabbits had a greater degree of diffuse cellular infiltration into interstitial splits in the graft than controls after 12 weeks. Xenografts implanted in an ovine extensor tendon deficit were evaluated after 26 and 52 weeks. Rate of failure of tenorrhaphies between host tendon and xenografts overall (15/21) was significantly greater (P < 0.05) than for autografts (1/21), suggesting that the holding power of sutures in xenografts was inferior to that obtained in autografts. Tensile failure stress of midsections of both nitrous acid pretreated and control xenografts was about 100 MPa prior to implantation (time zero). After 26 and 52 weeks, failure stress of both types of xenografts was significantly less than at time zero (P < 0.05). At 52 weeks, failure stress of nitrous acid pretreated xenografts (47.4 +/- 3.1 MPa) was significantly less than control xenografts (63.7 +/- 5.4 MPa); (P < 0.05). However, nitrous acid pretreated xenografts were similar to control xenografts in failure load (357 +/- 29 and 354 +/- 26 N, respectively), but they tended to have larger cross-sectional areas (7.6 +/- 0.5 versus 5.7 +/- 0.6 mm2, respectively) which were responsible for the lower calculated value for failure stress. Histologically, autografts maintained their normal tissue architecture and evoked a more limited cellular response in surrounding tissues than xenografts (P < 0.05). Both types of xenograft were surrounded by a thicker cuff of cellular response than autografts. However, compared to control xenografts, nitrous acid pretreated xenografts had more extensive fragmentation and splitting of collagen bundles, and more diffuse cellular and vascular infiltration into these interstitial splits, and these alterations were apparently contributing to the greater 'swelling' of these xenografts. It was concluded that pretreatment of tendon xenografts with nitrous acid modulated their biologic and material properties. Further studies are needed to elucidate the mechanism of these effects, and to determine if the protocol for tendon xenograft preparation could be optimized for improved clinical performance.

Animals↗
PubMed1984

Primary surgical closure of ventricular septal defect in the first year of life: results in 128 infants.

Between January 1973 and July 1981, 128 patients less than 1 year of age with failure to thrive, congestive heart failure or pulmonary artery hypertension underwent primary repair of a ventricular septal defect. The hospital mortality rate was 7.8% (10 of 128), and the late mortality rate was 2.3% (3 of 128). Mortality was highest among younger infants with preexisting respiratory problems or a hemodynamically significant residual lesion postoperatively. Complications included a large residual shunt in eight (6.2%), transient neurologic problems in five (3.9%) and persistent complete heart block in three (2.3%). Lung biopsy specimens obtained from 49 patients showed pulmonary vascular abnormalities in all. Complete right bundle branch block developed in 74 (64%) and bifascicular block appeared in 11 (9%). Recatheterization in 70 patients (55%) showed normal pulmonary artery pressures in all but 2 patients with a large residual shunt. Complete closure of the defect had been achieved in 49 (70%), and a hemodynamically insignificant shunt remained in 19 (27%). Patients without significant hemodynamic residua were asymptomatic and tended to accelerate in growth after surgery.

Age Factors↗