Preparation of soluble guanylyl cyclase from bovine lung by immunoaffinity chromatography.
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Amino Acid Sequence↗
Biomedical subjects
B Mayer
Publications and source records attributed to B Mayer.
Oxidized low-density lipoprotein antagonizes the activation of purified soluble guanylate cyclase by endothelium-derived relaxing factor but does not interfere with its biosynthesis.
Oxidized low-density lipoprotein (LDLox) is a molecule with strong atherogenic properties. In a concentration dependent fashion, LDLox antagonized the activation of purified soluble guanylate cyclase by endothelium-derived relaxing factor (EDRF), which was produced in vitro by incubation of a partially purified EDRF-forming enzyme in the presence of L-arginine, Ca2+ and NADPH. The inhibitory effect of LDLox was potentiated by preincubation of the soluble guanylate cyclase with LDLox, but not when the EDRF-forming enzyme was pretreated with LDLox. As LDLox did not diminish the calmodulin-dependent conversion of L-arginine into L-citrulline by the EDRF-forming enzyme it would appear that EDRF-biosynthesis was not affected by LDLox. It is suggested that the impaired relaxant response of atherosclerotic blood vessels to endothelium-dependent vasodilators was not due to a reduced formation of EDRF but due to a diminished responsiveness of soluble guanylate cyclase.
Animals↗
Eversion endarteriectomy of the internal carotid artery.
Eversion endarteriectomy has been proposed as a reliable and rapid method for operating on an ulcerated or stenosed internal carotid artery. The surgical technique is presented in detail. The perioperative course is appraised in a series of 60 operations. Irrespective of age and other diseases in the patients and the preoperative state of the ipsilateral and contralateral vessels, a perioperative morbidity of 1.6% (a temporary neurological deficit) and no lethal outcomes were found. Indication for operation on the carotid artery depends on the spontaneous prognosis based on the vascular morphology and the rate of perioperative complications. The method of surgery described establishes favorable conditions for endarteriectomy even in the asymptomatic stage as well as in exulcerative lesions of the carotid wall.
Carotid Artery, Internal↗
[Free microsurgical latissimus dorsi muscular flaps in swine. In-vitro model for the experimental continuous development of microsurgical reconstruction in the head-and-neck area].
An in-vitro system for research into microsurgical transfer technology in head and neck reconstruction is presented for the first time: the free, muscular latissimus-dorsi-flap of the pig. This in-vitro-system is useful for training in microsurgical techniques, for biomechanical tests of vascular connections, and for the simulation of extracorporal circulatory systems in free flaps. This in-vitro system corresponds to human surgical conditions and anatomical proportions. It helps reduce the number of animals needed in microsurgical research and therefore complies with present legislation. The article outlines the surgical technique of raising and replanting the free flap and its cold storage.
Animals↗
[Connector technology: development of simple rapid transfer of free microsurgical tissue flaps in the head and neck region].
The aim of this research program was to develop vessel connectors to replace the difficult microsurgical suture, which could be implanted quickly, safely and without any special training. Three types of connectors were developed specially for the anatomical features of the head and neck region: miniconnectors, stick connections with vascular prosthesis, and interposition connectors. The development of the model, the biomechanical tests on the in-vitro system comprising a free, muscular, porcine latissimus-dorsi flap, and the in-vivo tests involving implantation of the connectors in vessels of rats, rabbits, dogs and pigs are outlined. The results are compared with those obtained with conventional microsurgical interrupted sutures.--The indications for these three different types of connector are determined by the diameter and quality of the vessels (vein, artery).
Animals↗
[Concept and technique for closure of septum defects].
A surgical concept for the closure of perforations of the septum is presented. Small and medium-sized defects are closed by a one-step extramucosal technique also used in rhinoplasties. Tissue tubes of mucoperichondrium, mucoperiosteum and the upper lateral cartilage are mobilized in both nasal lumina. Parts of the lamina quadrangularis are dissected and shifted to close the defect. Very large defects with a diameter of more than 3 cm are closed in a three-step technique. A spoon-shaped flap from the oral vestibule with a piece of ear cartilage attached is inserted into the perforation. The cartilage is covered with oral mucosa on both sides. These procedures are superior to traditional techniques in terms of both blood supply and safe closure.
Humans↗
[Technique of microvascular jejunum transfer for replacement of the cervical esophagus].
Technique and results of the first 10 free jejunal grafts after pharyngolaryngectomy are presented. End-to-side venous anastomosis and end-to-side pharyngojejunostomy instead of end-to-end techniques are proposed. Hospital mortality was 0 and as minor complications 1 uncomplicated fistula of the proximal and 1 stenosis of the distal anastomosis along with 1 wound infection were seen. There were no vascular complications and no graft loss. All patients were able to swallow and to eat thus an excellent quality of life was achieved.
Adult↗
[Systematic indications of various free transfer flaps in the area of the head and neck].
Many microsurgical free flaps have been described to tackle various problems in the head and neck. The authors present a system of indications which has proved to be suitable as judged by the functional and cosmetic results obtained. The harvesting of these flaps requires versatile training in surgical techniques for the different anatomical areas. This system of indications comprises the free fasciocutaneous forearm flap, jejunal loops, the fasciocutaneous parascapular flap, iliac crest flaps with vascularized bone and the parascapular cutaneous, latissimus dorsi osteomyocutaneous double flap.
Bone Transplantation↗
Purification of a Ca2+/calmodulin-dependent nitric oxide synthase from porcine cerebellum. Cofactor-role of tetrahydrobiopterin.
L-Arginine-derived nitric oxide acts as an inter- and intracellular signal molecule with cytosolic guanylyl cyclase as the effector system. Two NO synthase isoenzymes are postulated: a cytokine-inducible enzyme in macrophages and a constitutive, Ca2(+)-regulated enzyme in various other cells. An NO synthase was isolated from porcine cerebellum by ammonium sulfate precipitation and affinity chromatography on 2',5'-ADP-Sepharose. The enzyme was identified as an NO synthase with a specific NO-chemiluminescence method and with purified cytosolic guanylyl cyclase as an NO-sensitive detection system. The purified NO synthase was, besides Ca2+/calmodulin and NADPH, largely dependent on tetrahydrobiopterin as a cofactor.
Amino Acid Oxidoreductases↗
Activation of soluble guanylate cyclase by nitrovasodilators is inhibited by oxidized low-density lipoprotein.
In the presence of oxidized low-density lipoprotein the stimulatory effects of nitric oxide, sodium nitroprusside and S-nitrosoglutathione on soluble guanylate cyclase partially purified from bovine platelets were diminished in a concentration-dependent manner with IC50 values around 100 micrograms total cholesterol/ml. This inhibitory effect was potentiated about 10-fold when the enzyme was pre-incubated with the lipoprotein for 10 minutes at 37 degrees C which indicates a direct interaction of the lipoprotein with the guanylate cyclase. As oxidized low-density lipoprotein is present in the wall of atherosclerotic arteries, we suggest that the impaired response of atherosclerotic blood vessels to vasodilators may be due to a diminished activation of smooth muscle guanylate cyclase.
Animals↗
Purification of soluble guanylyl cyclase from bovine lung by a new immunoaffinity chromatographic method.
Soluble guanylyl cyclase was purified from bovine lung by an immunoaffinity chromatographic method using IgG fractions of antisera against a synthetic peptide of the C-terminus of the 70-kDa subunit of the enzyme. After anion-exchange chromatography, the enzyme was bound to an immunoaffinity column and was eluted with the synthetic peptide. This method allowed the convenient isolation of 2 mg of apparently homogeneous enzyme from 40 g cytosolic proteins. The enzyme had an apparent molecular mass of about 150 kDa and consisted of two subunits (70 kDa and 73 kDa) as determined by gel permeation fast protein liquid chromatography and SDS/PAGE. The basal activities determined in the presence of Mg2+ and Mn2+ were 10-20 nmol.min-1.mg-1 and 80-100 nmol.min-1.mg-1, respectively. The enzyme exhibited an ultraviolet-visible absorption spectrum typical for hemoproteins, with a Soret band at 430 nm. The purified enzyme was stimulated by NO-containing compounds. Maximal enzyme activities measured in the presence of sodium nitroprusside were 1.2-2.4 mumol.min-1.mg-1 (half-maximal effect of sodium nitroprusside at 1.3-1.9 microM) and 0.9-1.8 mumol.min-1.mg-1 (half-maximal effect at 0.28-0.41 microM sodium nitroprusside) in the presence of Mg2+ and Mn2+, respectively. The method developed for the large-scale purification of soluble guanylyl cyclase by immunoaffinity chromatography, using synthetic peptides for the elution of the enzyme, appears to be superior to previously described methods. As antibodies against synthetic peptides corresponding to deduced amino acid sequences of the respective protein are easily obtained, the described method may be suitable for a convenient large-scale purification of various proteins.
Animals↗
[Mini-septoplasty--for function and form].
Septoplasty often provokes aesthetic and unaesthetic sequelae of the anterior third and the tip of the nose. In a retrospective study of 100 patients these changes and sequelae have been analysed preoperatively and six months postoperatively. The postoperative changes are systematically referred to the surgical steps described in the operation notes. The dynamics of sculpturing the anterior border of the quadrangular cartilage, the effects of septal realignment, the influence on the tip support structures are outlined. The importance of minimum surgical touch is stressed. Examples of aesthetic and unaesthetic sequelae caused by functional septoplasty are presented.
Esthetics↗
[Intraoperative protection of free microsurgical transfer flaps: "cold storage" in HTK-1 solution].
There is a rule of thumb that an ischaemia time of 6 hours should not be exceeded when preserving a free flap. Microsurgical reconstructions sometimes require a long operation time and a long tolerance of ischaemia of the free flap. Using Bretschneider's HTK solution for the intraoperative cold storage of free flaps with a temperature of 5-7 degrees C, an ischaemia time of 12 hours should not affect the free flap, and hence the time limit of the ischaemic tolerance looses its importance. Based on Bretschneider's research results of cardioplegia and of the ischaemic tolerance of the kidney and the liver, we chose the HTK solution for the intraoperative protection of free microsurgical flaps.
Cardioplegic Solutions↗
[Unilateral reconstruction of the anterior neck using a combination flap technique].
This technique is recommended for the one-stage reconstruction of the cervical esophagus, for the protection of the cervical vessels by soft tissues and for the substitute of the anterior neck skin. The microvascular free jejunal flap is transplanted and then covered by the myocutaneous pectoralis-major-island-flap. Indications are complete defects of the anterior neck after the resection of tumors, after the resection of necrotic tissues following radionecrosis, when all soft tissues in front of the prevertebral fascia have to be resected. Details of the surgical technique are explained. This combination flap technique proved to be useful in 4 patients without any complications.
Aged↗
[Lipomatous atrophy of the parotid gland in chronic alcohol consumption].
The effect of chronic ethanol consumption on the morphology of the rat parotid gland was investigated. After feeding an ethanol diet containing 36% of total calories as ethanol for 90 days light microscopic and electron microscopic investigations of the parotid gland tissue showed a striking fat accumulation compared to control rats. Besides interstitial fat tissue dispositions, fat droplets of various size occurred in most of the acinar cells. Additional morphometric investigations revealed a decrease in mean acinar cell volume (-21.9% p greater than 0.001). The latter finding reflects an atrophy of the secretory parenchyma and appears to be responsible for the impaired saliva secretion after chronic ethanol consumption which has been observed in former studies.
Alcohol Drinking↗
Effect of calcium on endothelium-derived relaxing factor formation and cGMP levels in endothelial cells.
Various stimulants of the release of EDRF (endothelium-derived relaxing factor) increased intracellular cGMP levels in bovine aortic endothelial cells. ATP was the most effective compound tested, increasing cGMP 7-fold, followed by the calcium ionophore, A23187 (4.8-fold), and bradykinin (4.0-fold). The EC50 values were similar to those obtained when EDRF release was measured with the bioassay technique, which suggests a stimulation of endothelial guanylate cyclase by EDRF. The direct acting stimulants of soluble guanylate cyclase, sodium nitroprusside and SIN-1 (3-morpholino-sydnonimine), also increased the cGMP content of endothelial cells by 9.4 and 7.2 times, respectively. The effects of both groups of stimulants on cGMP levels were antagonized by the lipoxygenase inhibitor, nordihydroguaiaretic acid, and by the radical scavenger, phenylbutylnitrone, whereas gossypol or canavanine only antagonized the EDRF-induced effect on endothelial cGMP levels. Bradykinin, ATP and A23187 also increased the uptake of 45CaCl2 into endothelial cells but since the complete removal of extracellular Ca2+ or blockade of Ca2+ transport by LaCl3 did not affect the ability of these compounds to elevate cGMP levels, the formation of EDRF appears not to be triggered by an influx of extracellular calcium. This study provides evidence that EDRF stimulators enhance cGMP levels in endothelial cells, probably due to a direct activation of guanylate cyclase by EDRF.
Animals↗
Biosynthesis of endothelium-derived relaxing factor: a cytosolic enzyme in porcine aortic endothelial cells Ca2+-dependently converts L-arginine into an activator of soluble guanylyl cyclase.
In the presence of porcine aortic endothelial cytosol, soluble guanylyl cyclase purified from bovine lung was activated by L-arginine up to 2.5-fold, with an EC50 of about 6 microM. This activation was dependent on NADPH and Ca2+. The EC50 for Ca2+ was about 60 nM. No effect of L-arginine on guanylyl cyclase was observed when the cytosolic proteins were heat-denaturated. The effect of L-arginine was inhibited by NG-monomethyl-L-arginine and hemoglobin. These results indicate that endothelial cells contain a cytosolic enzyme which is directly or indirectly regulated by Ca2+ and converts L-arginine into a compound which in stimulating soluble guanylyl cyclase behaves similar to endothelium-derived relaxing factor.
Animals↗
Analyzing-power measurement in p
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Journal Article↗