Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “vascular bundle”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed2006

Functional characterization of phosphoenolpyruvate carboxykinase-type C4 leaf anatomy: immuno-, cytochemical and ultrastructural analyses.

BACKGROUND AND AIMS: Species having C4 photosynthesis belonging to the phosphoenolpyruvate carboxykinase (PEP-CK) subtype, which are found only in family Poaceae, have the most complex biochemistry among the three C4 subtypes. In this study, biochemical (western blots and immunolocalization of some key photosynthetic enzymes) and structural analyses were made on several species to further understand the PEP-CK system. This included PEP-CK-type C4 species Urochloa texana (subfamily Panicoideae), Spartina alterniflora and S. anglica (subfamily Chloridoideae), and an NADP-ME-type C4 species, Echinochloa frumentacea, which has substantial levels of PEP-CK. KEY RESULTS: Urochloa texana has typical Kranz anatomy with granal chloroplasts scattered around the cytoplasm in bundle sheath (BS) cells, while the Spartina spp. have BS forming long adaxial extensions above the vascular tissue and with chloroplasts in a strictly centrifugal position. Despite some structural and size differences, in all three PEP-CK species the chloroplasts in mesophyll and BS cells have a similar granal index (% appressed thylakoids). Immunolocalization studies show PEP-CK (which catalyses ATP-dependent decarboxylation) is located in the cytosol, and NAD-ME in the mitochondria, in BS cells, and in the BS extensions of Spartina. In the NADP-ME species E. frumentacea, PEP-CK is also located in the cytosol of BS cells, NAD-ME is very low, and the source of ATP to support PEP-CK is not established. CONCLUSIONS: Representative PEP-CK species from two subfamilies of polyphyletic origin have very similar biochemistry, compartmentation and chloroplast grana structure. Based on the results with PEP-CK species, schemes are presented with mesophyll and BS chloroplasts providing equivalent reductive power which show bioenergetics of carbon assimilation involving C4 cycles (PEP-CK and NAD-ME, the latter functioning to generate ATP to support the PEP-CK reaction), and the consequences of any photorespiration.

Blotting, Western↗
PubMed1997

Bullous lesions in Kaposi's sarcoma: case report.

Bullous lesions have been only rarely described in Kaposi's sarcoma (KS), and their histopathologic features have never been described in detail. We report a case of bullous lesions of KS in an 82-year-old Italian woman. The patient had typical smooth pale reddish-grey slightly-raised KS plaques on the legs, present for at least 10 years. Several dull grayish-pink blisters (0.5 to 2 cm in diameter) affected both dorsa of her feet and ankles symmetrically. Two punch biopsies were taken, one from an infiltrated KS plaque on the right buttock and the other from a bullous lesion on the right foot. Histopathologically, the late KS plaque on the buttock showed typical features of KS, with an increased number of spindle cells arranged in short bundles and extravasation of erythrocytes. The bullous lesion on the foot showed a full-thickness vascular neoplasm involving the upper and lower dermis and the subcutaneous fat. The upper portion of the lesion contained many newly formed, highly-dilated blood vessels, touching the overlying epidermis and separated from it by a narrow band of collagen and endothelial cells; wide, empty spaces characterized the superficial dermis, in which preexisting venules and bands of collagen associated with non-atypical endothelial cells floated. All these findings would suggest a lymphangiomatous lesion, if the presence of specific diagnostic criteria of KS were not recognizable at a deeper level of the lesion. Various criteria actually suggest that the bullous lesion may be regarded as an epiphenomenon of a KS plaque lesion: (a) full-thickness involvement of the reticular dermis and, in this case, also of the subcutaneous fat; (b) dense and patchy lymphoplasmocytic infiltrate typical of plaque lesions and, much less frequently, of patch lesions; (c) presence of ectatic blood vessels, filled with plasma and erythrocytes (pseudoangiomatous findings), a nonpathognomonic but highly characteristic finding of the plaque lesion; and (d) as in the KS plaque lesions, in the bullous lesion as well the reticular dermis was characterized by an increased number of anastomosing bizarrely shaped vascular spaces lined by non-atypical endothelial cells. We hypothesize that the prevalence of lymphangiomatous differentiation in the upper dermis represents one of the many features of KS lesions. When present, it may correlate with the clinical feature of a blister.

Adipose Tissue↗
PubMed1991

[Presence of neuritic plaques and neurofibrillary changes in the cerebral cortex of an aged lemuride primate].

Some aged Microcebus murinus brains (8 to 11-years old animals) displayed a dramatic atrophy particularly in the neocortex, hippocampus, basal ganglia, hypothalamus, brainstem and cerebellum, associated with a conspicuous increase in the size of the cerebral ventricles. These morphological changes were accompanied by certain histological profiles indicative of pathology. In the cortex, these histological changes consisted of (1) a large number of neuritic plaques formed by degenerated neurites sometimes surrounding an amyloid plaque, (2) dense bundles of argyrophilic filaments in many pyramidal neurons, and (3) amyloid deposits in and around the vascular walls. So far these preliminary studies cannot prone that this degeneration is similar to the human senile dementia of Alzheimer's type, but they may indicate that Microcebus murinus may well be a good model to study cerebral aging, providing comparisons with humans. Furthermore, the size, life span and cost of this species provide further advantages over other nonhuman primates.

Aging↗
PubMed1996

[Forensic medical implications of vascular injuries in orthopedic surgery].

The vascular risk in orthopedic surgery results from the close relation between bones and vessel-nerve bundles, the use of sharp cutting and perforating instruments and, in hip surgery, the use of cement. The two main prognosis factors are early diagnosis and the time of treatment. Here we review risks by localizations. For spinal surgery, the great vessels may be damaged by discetomy and can lead to intraperitoneal bleeding and death or arteriovenous fistulization. In the scapular area, pin migrations after surgery involving the clavicle can lead to bleeding or false aneurysms of the subclavian artery. When surgery is performed for thoraco-brachial outlet syndromes, arterial damage is less frequent than nerve damage which can lead to death (one case reported) or severe sequelae. Hip surgery can damage the iliac or femoral vessels with severe sequelae after total hip replacement. Two cases of death related to femoral neck fracture and anticoagulant treatment are reported. Two other cases of lesions to the femoral artery with severe sequelae after treatment of diaphyseal fractures of the femur are also reported. In the knee area, consequences of surgery can be particularly severe, especially unrecognized damage or incorrect treatment of the popliteal artery after osteoarticular injuries, or iatrogenic lesions after knee surgery. Finally two cases of tibial artery lesions are reported. In most of these cases, medicolegal consequences were confirmed by court judgements.

Blood Vessels↗
PubMed1977

Structure of a juxtaglomerular cell tumor: the presence of a neural component: a light and electron microscopic study.

A 15-year-old girl with hypertension, markedly elevated plasma renin activity, and normal aortogram had a well encapsulated tumor nodule removed from the right kidney. Following surgery, the plasma renin activity and blood pressure became normal and have remained so for the past 12 months. The tumor consisted of juxtaglomerular cells filling the interstitium between endothelium-lined vascular spaces. Electron microscopy disclosed the presence in the interior of the tumor, of unmyelinated nerve bundles with varicosities containing the small, densely cored vesicles characteristic of adrenergic nerves. Nerve terminals were in contact with the juxtaglomerular tumor cells. No basement membrane material was interposed between the nerve endings and the tumor cell; the width of the gap between the two plasma membranes was approximately 150 A. The presence of sympathetic fibers in the juxtaglomerular cell tumor underscores the close biologic relationship between the sympathetic and renin systems.

Adolescent↗
PubMedDate not supplied

[The formation of the human epiphysis and its dynamic development at the stage of early embryonic differentiation].

We studied the epiphysis of human embryos at stages from 18 to 63 mm of occipital-sacral length (OSL). We found that the epiphysis is formed by migration of cells from the roof of the diencephalon in the dorso-caudal direction. At this time, the epiphysis undergoes active vascularization, initially through pinealocytes filling the space between capillaries, and then by the ingrowth of the bundle of nerves and vessels into the epiphysis. The nerve entering the epiphysis, together with vessels, subsequently becomes a source of innervation for the epiphysis of the adult human. Analysis of qualitative correlations between epiphysis development and linear growth of the embryo has demonstrated that the rate of the increase of epiphyseal volume is significantly higher than the rate of the increase of the embryo's occipital-sacral length. Asynchrony in the rate of growth of epiphysis and embryo is highly individual, since increase in volume per 1 mm of length may differ at different stages by a factor of two or even more.

Cell Differentiation↗
PubMed2000

Clitoroplasty with preservation of neurovascular pedicles.

BACKGROUND: Optimal sexual function after surgical correction of clitoral hypertrophy requires an adequate postoperative innervation and vascular supply to the glans clitoris. Several clitoroplasty methods have been reported, but few describe preservation of dorsal and ventral neurovascular bundles in sexually mature women. CASE: A 22-year-old woman with clitoromegaly caused by non-salt-wasting classic 21-hydroxylase deficiency presented for a second surgical procedure after an operation in her infancy. The erect clitoral length exceeded 7.5 cm. Clitoral reduction was done through a semicircular incision in the phallus, with preservation of dorsal and ventral neurovascular pedicles. CONCLUSION: Preservation of ventral and dorsal vascular pedicles at clitoroplasty had a satisfactory result in sexually mature women.

Adult↗
PubMed1998

Limitations of percutaneous transhepatic cholangioscopy for the diagnosis of the intramural extension of bile duct carcinoma.

BACKGROUND AND STUDY AIMS: Vascular dilatation seen on percutaneous transhepatic cholangioscopy (PTCS) is diagnostic of intramural invasive carcinoma of the bile duct, but the limitations of the technique, including biopsy, for the diagnosis of intramural extension of bile duct carcinoma have not to our knowledge been investigated before. The aims of the present study were to estimate the thickness of the specimens of bile duct wall taken by biopsy, to assess the sensitivity of PTCS for detecting intramural invasive carcinoma, and to identify the characteristics of the intramural extension of bile duct carcinoma associated with vascular dilatation. PATIENTS AND METHODS: A total of 135 biopsy, and 16 surgical specimens obtained from 25 bile duct carcinomas were examined for: the thickness of the biopsy specimens and of the mucosa and combined mucosal-fibromuscular layers in the resected common bile ducts and common hepatic ducts; the presence of muscular and neural bundles in the biopsy specimens; the number of invasive carcinomas in the biopsy specimens that had been taken from stenosed regions; and the relation between intramural extension of invasive carcinoma and vascular dilatation. RESULTS: The mean thickness of the biopsy specimens did not differ from the mean thickness of the mucosa in the resected specimens, but was significantly lower than that of the combined mucosa and fibromuscular layer. Muscular bundles were included in only 13 (14%) of the biopsy specimens, and there were no neural bundles. Carcinomas and invasive carcinomas were diagnosed histologically from the biopsy specimen in 96% and 91% of the cases, respectively. The sensitivity of a single biopsy for diagnosis for invasive carcinoma in stenosed regions was 62%, almost the same as the sensitivity in non-stenosed regions with vascular dilatation (68%). On histologic examination of 16 resected specimens, the sensitivity and specificity of vascular dilatation as a marker of the intramural extension of an invasive carcinoma were 39% and 100%, respectively, and this was significantly more common in invasive carcinomas that were invading the mucosa beyond the adventitia than in those limited to the adventitia. CONCLUSION: Histologic examinations of specimens obtained by PTCS-guided biopsy can detect invasive carcinoma in only the superficial layers of the bile duct, such as the mucosa and the shallowest fibromuscular layer. Multiple specimens are needed for the diagnosis of invasive carcinoma because the sensitivity of examination of a single specimen for detecting invasive carcinoma is low. Vascular dilatation is characteristic of carcinoma that is invading the mucosa beyond the adventitia, so the diagnosis of intramural extension of bile duct carcinoma limited to the adventitia, particularly if it has spread to the deeper fibromuscular layer and the adventitia, is difficult to make by PTCS.

Adult↗
PubMed1975

The action of arachidonic acid on experimental hypertension in the rat.

Keeping in mind the vasodilator action of prostaglandins, the control that they exercise over the vascular supply of kidneys and the sympathetic activity, research was conducted in order to establish the effect of arachidonic acid, the precursor of PGE2, on experimental hypertension in the rat. The experimental hypertension was induced by unilateral nephrectomy, followed by the administration of DOCA and the elevated sodium diet. The treatment was short in one group, long in the other, and both groups were compared to a control hypertensive group which received no treatment at all. Arachidonic acid worsened the experimental hypertension by 37% in the long treatment, and by 25% in the short treatment. The administration of lysine-acetylsalicylate diminished this hypertension. A non-saturated acid, oleic acid, which is not involved in prostaglandin synthesis, has no action. The authors would like to emphasize that in one of the previous experiments, L-tyrosine, the precursor of catecholamines, diminished the experimental hypertension in the rat, and also that L-DOPA and IMAO (MAOI) have comparable effects. It seems, therefore, that the depression of the central catecholaminergic activity, which is supposed to be the action of arachidonic acid via an increase in the PGE2 synthesis, appears to increase hypertension. It is noteworthy that the medial forebrain bundle (MFB) is catecholaminergic and that the periventricular system (PVS) is cholinergic. Thus hypertension may represent the peripheral vascular response to anguish which results from the activation of PVS and from the depression of MFB.

Administration, Oral↗
PubMed1985

Microvascular pericytes contain muscle and nonmuscle actins.

We have affinity-fractionated rabbit antiactin immunoglobulins (IgG) into classes that bind preferentially to either muscle or nonmuscle actins. The pools of muscle- and nonmuscle-specific actin antibodies were used in conjunction with fluorescence microscopy to characterize the actin in vascular pericytes, endothelial cells (EC), and smooth muscle cells (SMC) in vitro and in situ. Nonmuscle-specific antiactin IgG stained the stress fibers of cultured EC and pericytes but did not stain the stress fibers of cultured SMC, although the cortical cytoplasm associated with the plasma membrane of SMC did react with nonmuscle-specific antiactin. Whereas the muscle-specific antiactin IgG failed to stain EC stress fibers and only faintly stained their cortical cytoplasm, these antibodies reacted strongly with the fiber bundles of cultured SMC and pericytes. Similar results were obtained in situ. The muscle-specific antiactin reacted strongly with the vascular SMC of arteries and arterioles as well as with the perivascular cells (pericytes) associated with capillaries and post-capillary venules. The non-muscle-specific antiactin stained the endothelium and the pericytes but did not react with SMC. These findings indicate that pericytes in culture and in situ possess both muscle and nonmuscle isoactins and support the hypothesis that the pericyte may represent the capillary and venular correlate of the SMC.

Actins↗
PubMed2003

Localisation of WE-14 immunoreactivity in the developing mouse limbo-corneal nerve net.

WE-14 is generated in subpopulations of chromogranin A immunopositive endocrine cells and neurons including those innervating the anterior uvea. This study investigated WE-14 in intact sclero-limbo-corneal tissue from embryonic (E17), neonatal (N0-N16), and adult mice using immunocytochemistry and confocal scanning laser microscopy. Weak WE-14 immunostaining was observed at birth in nerve fibre tracts entering the corneal mid-stroma from the limbo-scleral junction. Immunopositive fibre tracts were evident throughout the cornea at N3; by N5 the mid-stromal plexus had begun to generate fibre populations extending toward the developing corneal epithelium, and some varicose fibres terminated amongst the developing epithelium. Immunostaining was evident at N7 in the developing limbo-scleral nerve net and some fibres exhibited a close association with unidentified vascular elements. By N11 and in subsequent neonates, the cornea had developed a distinct stratified nerve net composed of thick mid-stromal and thinner upper stromal nerve fibre bundles; both possessed populations of varicose WE-14 immunopositive fibres. In the adult, a sub-epithelial network of varicose WE-14 immunopositive fibres were evident at the limbo-scleral junction. Some fibres exhibited a close association with unidentified vascular elements, while others extended into the upper peripheral corneal stroma. WE-14 was evident in leashes throughout the basal corneal epithelium and generated fibres ramifying between the stratified epithelium with some fibres terminating amongst the outermost corneal epithelia. This study has demonstrated that WE-14 was evident in the limbo-corneal nerve net at birth and that its detection parallels corneal development to adulthood, where WE-14 is evident in a subpopulation of nerve fibres.

Animals↗
PubMed1989

Changing electrocardiographic findings in pulmonary embolism in relation to vascular obstruction.

Electrocardiographic (ECG) findings in 87 consecutive patients with from minor to massive pulmonary embolism are presented. ECG changes suggestive of acute right ventricular strain defined as the occurrence of complete (c) or incomplete (inc) right bundle branch block (RBBB), an SIQIIITIII pattern, inverted T waves in the second and third precordial leads and/or an increase in the frontal QRS axis of 20 degrees C or more were found in 71 patients (82%). The prevalence of c and inc RBBB and the increase in frontal QRS axis correlated with the extent of embolization (angiographic or scintigraphic score), while the appearance of the SIQIIITIII pattern did not. No patient with a vascular obstruction of two thirds or more had an ECG free of signs of right ventricular strain. In 9 of 11 embolectomized patients with c RBBB, c RBBB disappeared within 24 h postoperatively. Among patients with an embolization of 45% or more, those with c RBBB had a shorter symptom duration, fewer embolic episodes and a lower pulmonary artery pressure than those without c RBBB. As ECG abnormalities were transient and changing in nature, serial ECG recordings are recommended. Pronounced ECG signs of right ventricular strain should, as they may reflect both massive and short-lasting vascular obstruction, arouse the suspicion of pulmonary embolism suitable for embolectomy.

Adolescent↗
PubMed1993

Superior mesenteric arteriovenous fistula in vascularized whole organ pancreatic allografts.

Despite improved results in vascularized pancreatic transplantation, the incidence of technical complications continues to be high. Vascular complications are an important source of morbidity. Previously undescribed is the occurrence of an arteriovenous fistula (AVF) in the transplanted mesenteric bundle. We have identified this unusual complication in three of 90 consecutive recipients of pancreatic transplant. The first patient presented with severe and protracted endocrine insufficiency, which was effectively reversed by direct surgical ligation of the AVF. The second patient presented with hematuria, which likewise, resolved with correction of the AVF. The third instance was diagnosed immediately after transplant and was successfully corrected by direct surgical ligation. The operative approach with establishment of proximal vascular control differed in each instance. Clinical presentation was variable and diagnosis was suggested by physical examination, duplex ultrasonography and radionuclide perfusion scanning. Arteriography was confirmatory. Mesenteric AVF can be easily identified and corrected at the time of reoperation without compromising allograft function.

Adult↗
PubMed2007

Resection of soft tissue sarcoma of the lower limb after evaluation of vascular invasion with intraoperative intravascular ultrasonography.

BACKGROUND: This study investigated the value of intravascular ultrasonography (IVUS) in the intraoperative assessment of vascular invasion of soft tissue sarcoma. METHODS: In a 4-year interval, of 337 patients with soft tissue sarcoma, 20 patients with tumours of the lower limb in close relation to the neurovascular bundle underwent intraoperative IVUS (20 MHz). Intraoperative findings were correlated with preoperative imaging, histopathological appearance of the resection specimen and patient outcome. RESULTS: Intraoperative IVUS was technically successful in all 20 patients. It correctly predicted vascular involvement (true positive) in ten of 11 patients who required resection of major vessels. There was one false-negative and one false-positive result. With magnetic resonance imaging, there were ten true-positive and three false-positive scans, and one false-negative diagnosis. IVUS improved the assessment of vascular involvement in four of the 20 patients. Histopathological examination confirmed complete resection (R0) in 18 patients. Mean survival was 37 months, and no local recurrence was observed in these patients. CONCLUSION: Vascular infiltration by soft tissue sarcoma can be visualized accurately by IVUS. This may improve intraoperative decisions about vessel resection.

Adult↗
PubMed1999

Sex difference in target seeking behavior of developing cremaster muscles and the resulting first visible sign of somatic sexual differentiation in marsupial mammals.

Cremaster muscles are present in both male and female developing and adult marsupial mammals. They are complex structures and composed of several distinct bundles of striated muscle fibers provided with: (1) a distinct and extensive innervation; (2) a distinct blood vascular supply; (3) a distinct tendineous origin on the anterosuperior iliac spine; and (4) distinct target structures. The muscles thus seem to be separate anatomical entities and not a part of one or more of the layers of the ventral abdominal wall musculature. Cremaster muscles in males are elongated, are larger than in females, and for the most part are a component of the funiculus spermaticus. They insert on the distal part of the tunica vaginalis. The distal parts of the muscles in females are flattened ("fan shaped") and insert over a broad area on the dorsal borders of the mammary glands. Muscles in males have no relation whatsoever to the male mammary glandular rudiments. Muscles in females are attached at the base of the uterine round ligament. The remarkable sex difference in target structures of marsupial cremaster muscles becomes noticeable during perinatal life when outgrowing muscles take a different path in males and females. The initial appearance of this sexually dimorphic trait precedes the sexual differentiation of the genital ducts and external genitalia. In fetal males, the cremaster muscles grow in the direction of the site where scrotal bulges initially appear in the subcutaneous layers and later on the inguinal skin surface. They also take the gubernacular core of the ventral abdominal wall and the attached peritoneal epithelium with them during this outgrowth process. Consequently, this results in the development of a slitlike evagination of the abdominal lumen as the primary step to development of the processus vaginalis, while the testis and adjacent mesonephros and its duct are still attached to the posterior abdominal wall. In fetal females, the outgrowing cremaster muscles pass along the gubernacular core and, subsequently, this structure develops further as the tip (attached to the tubo-uterine junction) of the intra-abdominally protruding and further developing uterine round ligament. The female cremaster muscles grow further into caudal direction to shape a dorsal border of the developing mammary glands. The early onset of this sexually dimorphic outgrowth of cremaster muscles indicates that the "classical hormones" of sexual differentiation (anti-Müllerian hormone [AMH] and steroidal androgens) are not involved in this process. It could thus depend on primary genetic control with male development associated with the male-limited activity of genes on the Y-chromosomes and female development as the default process. Alternatively, the process in males could be under the control of an as yet unidentified third fetal testicular hormone involved in sexual differentiation processes which must then show an unexpectely early (i.e., perinatal) onset of its secretion.

Animals↗
PubMed1995

Beta-adrenoceptor regulation and functional responses in the guinea-pig following chronic administration of the long-acting beta 2-adrenoceptor agonist formoterol.

Formoterol is a long acting beta 2-adrenoceptor agonist designed for the alleviation of the symptoms of asthma. This study examined the effects of 14 day administration of formoterol (200 micrograms/kg/day i.p.) on beta 1- and beta 2-adrenoceptors in guinea-pig cardiac and lung tissue. Quantitative autoradiography was used to measure changes in receptor density and organ bath studies determined alterations in functional response. Formoterol treatment produced marked reductions of between 43% and 77% in beta 2-adrenoceptor density in all regions of the heart (atrioventricular node, bundle of His, right and left bundle branches, interventricular and interatrial septa, right and left atria, ventricles and apex) and lung (bronchial and vascular smooth muscle and parenchyma) (P < 0.01, n = 6). beta 1-Adrenoceptor density remained unchanged in all cardiac and lung regions. In functional studies (-)-isoprenaline was 4 fold less potent at causing relaxation of carbachol (1 microM) precontracted tracheal smooth muscle (pD2: control 8.49 +/- 0.03, formoterol 7.91 +/- 0.10, P < 0.001, n = 4), but formoterol treatment did not change the ability of (-)-isoprenaline to elicit a maximum response. The pKB values for ICI 118,551, 7.33 +/- 0.08 in the control and 7.20 +/- 0.01 in formoterol treated animals, were between those expected for beta 1- and beta 2-adrenoceptors suggesting involvement of both subtypes in the response. In spontaneously beating right atria and electrically paced left atria, tissues in which responses are largely mediated by beta 1-adrenoceptors, there was no significant change in responses to (-)-isoprenaline (right atria pD2: control 8.45 +/- 0.02; formoterol 8.42 +/- 0.11; P = 0.77, n = 4) (left atria pD2: control 8.25 +/- 0.03; formoterol 8.47 +/- 0.08; P = 0.09, n = 4). In the presence of CGP 20712A (100 nM) the pKB values did not change with formoterol treatment (left atria: control 9.59 +/- 0.12, formoterol 9.66 +/- 0.12; P = 0.70, n = 4) (right atria: control 8.93 +/- 0.11, formoterol 9.11 +/- 0.07; P = 0.25, n = 4). The doses and route of administration of formoterol used in this study differs from those used clinically. However, this study demonstrates that chronic formoterol administration produces selective down-regulation of beta 2-adrenoceptors in the lung and heart. The changes in the lung are accompanied by a shift to the right in the concentration-response curve to beta-agonist stimulation with no change in the maximum response.

Adrenergic beta-Agonists↗
PubMed1994

Early blood-brain barrier changes in the rat following transient complete cerebral ischemia induced by cardiac arrest.

This study examined regional patterns of increased vascular permeability following transient global cerebral ischemia. Rats underwent 3.5, 5 or 10 min of cardiac vessel bundle occlusion, i.e. cardiac arrest. The animals were killed at 2, 3, 5 and 15 min, or 1, 3, 6 and 24 h after global cerebral ischemia. Thirty minutes before the end of each blood recirculation period, the electron dense protein tracer--horseradish peroxidase (HRP) was intravenously injected and rats were perfusion-fixed for light and electron microscopic analysis. Control rats showed no HRP leakage. Post-ischemic rats demonstrated random blood-brain barrier (BBB) alterations. Permeability alterations were spotty and widespread in cortical, thalamic, basal ganglia, hippocampal, brain stem regions, cerebellum and white matter. Peroxidase extravasation frequently involved arterioles, veins and venules surrounded by perivascular spaces. Routes of increased HRP permeability included endothelial cell (EC) vesiculo-canalicular profiles and diffuse leakage through damaged ECs. Barrier damage determined by HRP permeability revealed a biphasic nature. The first stage appeared immediately after ischemia at the 2nd min and involved the 1st post-insult hour. There was no HRP leakage in rats sacrificed 3 h after insult. BBB opening appeared again 6 h after ischemia and remained open 24 h after cardiac arrest. The openings of BBB did not increase in frequency with longer periods of ischemia and recirculation. These results demonstrate that cardiac arrest produces a spotty BBB disturbances at vessel bifurcations and suggest that BBB changes associated with cardiac arrest may be multifactorial in time course and location.

Animals↗
PubMed2000

Enzyme- and immunohistochemical localization of nitric oxide synthase in nerves of the porcine pancreas.

The distribution of nitric oxide synthase (NOS) in neuronal and non-neuronal porcine pancreatic tissues was examined using nicotinamide adenine dinucleotide hydrogen phosphate diaphorase (NADPHd) enzymehistochemistry and neuronal type NOS immunohistochemistry. NOS-containing perikarya were regularly discernible in the pancreatic ganglia, whereas positive thin nerve fibers appeared within nerve bundles of the interlobular spaces and as thin varicose fibers in the vicinity of pancreatic blood vessels. Vascular endothelium showed intense staining for NADPHd and most of the islet cells were NOS immunoreactive. The above morphological findings indicate that nitrergic innervation of the porcine pancreas is very similar to that of the pancreata of other mammalian species and suggest that nitric oxide of both neuronal and extraneuronal origin may regulate blood flow and secretion of the porcine pancreas.

Animals↗