Antioxidant treatment restores prejunctional regulation of purinergic transmission in mesenteric arteries of deoxycorticosterone acetate-salt hypertensive rats.

Norepinephrine (NE) and ATP are co-released by periarterial sympathetic nerves. In mesenteric arteries (MA) from deoxycorticosterone-acetate (DOCA)-salt hypertensive rats, ATP, but not norepinephrine, release is impaired suggesting that their release may be regulated differently. We tested the hypothesis that different calcium channels contribute to ATP and norepinephrine release from sympathetic nerves in vitro in MA from normotensive and DOCA-salt hypertensive rats and that oxidative stress disrupts prejunctional regulation of co-transmission. Excitatory junction potentials (EJPs) were used to measure ATP release. Norepinephrine release was measured amperometrically with carbon-fiber microelectrodes. CdCl2 (30 microM) inhibited norepinephrine release in sham and DOCA-salt arteries by 78% and 85%, respectively. The N-type calcium channel antagonist, omega-conotoxin GVIA (CTX, 0.1 microM) inhibited norepinephrine release by 50% and 67% in normotensive and DOCA-salt arteries, respectively while CTX blocked EJPs. The P/Q-type calcium channel antagonist omega-agatoxin IVA (ATX; 0.03 microM) reduced norepinephrine release in sham but not DOCA-salt arteries and increased EJPs in sham but not DOCA-salt arteries. ATX did not increase EJPs in sham arteries in the presence of the alpha(2)-adrenergic receptor antagonist, yohimbine (1 microM). alpha(2)-Autoreceptor-sensitive EJP facilitation is impaired in DOCA-salt hypertension but this response is restored in DOCA-salt rats treated chronically with the antioxidant, apocynin. Apocynin restored alpha(2)-autoreceptor regulation of norepinephrine release. We conclude that ATP released from periarterial sympathetic nerves is controlled directly by N-type calcium channels. Norepinephrine release is controlled by N and P/Q type calcium channels. Norepinephrine release controlled by P/Q channels acts at alpha(2)-adrenergic receptors to inhibit norepinephrine release suggesting that there may be multiple pools of norepinephrine in periarterial sympathetic nerves. Regulation of norepinephrine release by alpha(2)-autoreceptors and P/Q-type channels is impaired in DOCA-salt hypertension and alpha(2)-autoreceptor function is disrupted by oxidative stress.

Insights into the structure, solvation, and mechanism of ArsC arsenate reductase, a novel arsenic detoxification enzyme.

BACKGROUND: In Escherichia coli bearing the plasmid R773, resistance to arsenite, arsenate, antimonite, and tellurite is conferred by the arsRDABC plasmid operon that codes for an ATP-dependent anion pump. The product of the arsC gene, arsenate reductase (ArsC), is required to efficiently catalyze the reduction of arsenate to arsenite prior to extrusion. RESULTS: Here, we report the first X-ray crystal structures of ArsC at 1.65 A and of ArsC complexed with arsenate and arsenite at 1.26 A resolution. The overall fold is unique. The native structure shows sulfate and sulfite ions binding in the active site as analogs of arsenate and arsenite. The covalent adduct of arsenate with Cys-12 in the active site of ArsC, which was analyzed in a difference map, shows tetrahedral geometry with a sulfur-arsenic distance of 2.18 A. However, the corresponding adduct with arsenite binds as a hitherto unseen thiarsahydroxy adduct. Finally, the number of bound waters (385) in this highly ordered crystal structure approaches twice the number expected at this resolution for a structure of 138 ordered residues. CONCLUSIONS: Structural information from the adduct of ArsC with its substrate (arsenate) and with its product (arsenite) together with functional information from mutational and biochemical studies on ArsC suggest a plausible mechanism for the reaction. The exceptionally well-defined water structure indicates that this crystal system has precise long-range order within the crystal and that the upper limit for the number of bound waters in crystal structures is underestimated by the structures in the Protein Data Bank.

DNA-ploidy, G2M-fractions and prognosis of stages B and C prostate carcinoma.

Paraffin embedded tissue of 49 stage C and 27 stage B prostate adenocarcinomas was investigated by flow cytometry. All patients were treated by radical prostatectomy with pelvic lymphadenectomy and followed up for 5-10 years. The tumour was separated from the benign tissue to increase the proportion of tumour cells. Ten stage C and seven stage B carcinomas had to be excluded because of poor fixation. Six of the 39 (15%) stage C and 1/20 (5%) stage B carcinomas were aneuploid. Cell cycle analysis was done with correction for sliced nuclei and background subtraction. The threshold between carcinomas with low and with increased ("tetraploid") G2M-fraction was determined by comparing carcinomas with and without tumour progression. Sixty-seven percent of the patients with non-euploid stage C carcinomas and 11% of those with euploid carcinomas suffered from tumour progression (P < 0.01). The respective values for the stage B carcinomas were 67% and 6% (P < 0.01). These results demonstrate the strong prognostic impact of DNA-ploidy and G2M-fractions for each individual patient.

Changes in muscle structure following tenotomy. A scanning electron microscopical study in the rat.

The alterations caused by Achilles tenotomy in the calf muscles of the rat were studied one, two and three weeks postoperatively by scanning electron microscopy (SEM). One week after tenotomy connective tissue had accumulated in endomyseal and perimyseal structures, which continued to increase even more after two and three weeks. The normal muscle architecture was markedly disturbed and in individual muscle cells hypercontracted segments, longitudinal splitting as well as destruction of myofilaments were found. Apparently due to the loss of muscle tension some muscle cells were reversed on their long axis and fixed with the adjacent collagen fibres. Some muscle cells were spiral in shape or crossing over each other. Formation of myotubes indicated onset of regenerative processes. According to the SEM-analyses tenotomy has many severe deleterious effects on muscle structure. In clinical practice tendon ruptures should therefore be repaired as soon as possible to avoid degenerative--potentially irreversible--changes in the muscular tissue.

[Chemical and microbiological studies of microwave-treated milk]. / Chemische und mikrobiologische Untersuchungen an mikrowellenbehandelter Milch.

Pasteurized milk was treated with microwaves for 2.5 minutes (2450 MHz, 650 W). Important chemical components (vitamin A, beta-carotin, vitamins B1, B2, C, E; activity of peroxidase, xanthinoxidase; content of fat and peroxides, percentage of solids, content of raw protein, content of all microorganisms and storage stability were examined. Ascorbic acid (reduction of 36%) and alpha-tocopherol (reduction of 17%) were influenced by microwave treatment, whereas other chemical parameters, odor and flavor remained unchanged. The content of microorganisms was reduced from about 10(4) to 10(2) per milliliter. Untreated milk had a content of 10(7) microorganisms per milliliter after 10 days storage at 8 degrees C and a taste of acidity, whereas in milk treated with microwaves only 10(4) microorganisms per ml were identified and no organoleptic changes could be observed after 14 days storage at 8 degrees C.

Pathological alterations in human tendons.

The present authors analyzed the pathological alterations of 1966 tendons examined in the National Institute of Traumatology, Budapest, during the past 18 years. The majority of cases proved to be tendinopathies (hypoxic-degenerative tendinopathy or calcific tendinitis, tendolipomatosis and mucoid degeneration) leading to tendon rupture. The incidence of tendon tumors, foreign bodies, infectious tendon diseases, and other pathological conditions was clearly lower. The methods of tissue preparation and of examination of tendon specimens were also evaluated. Light microscopy was sufficient for the diagnosis of pyogenic tendinitis, tumors, xanthoma, gout, and gangrene. In degenerative tendinopathies and alterations due to hereditary disease, electron microscopy was necessary. Polarization microscopy had a key role in examination of collagen structure and architecture, and identification of foreign bodies in the tendons. Enzyme histochemical and immunohistochemical examination were reliable but not absolutely necessary in the diagnosis of tendon pathology.

Fibronectin and laminin in Achilles tendon.

Ten intact and 22 ruptured Achilles tendons were studied by immunohistochemical techniques. In intact tendons, both fibronectin and laminin were found in vascular walls, myotendineal junction, and endomysium, but not in the connective tissue of the tendons. In ruptured tendons the distribution of laminin was not changed. Fibronectin deposits, on the contrary, could be detected on the tear surface and in the collagen fibers of the ruptured tendons.

Foreign bodies in tendons.

At the National Institute of Traumatology in Budapest, a search has been made for foreign bodies in tendons over the last 15 years. 53 foreign bodies have been found in 931 tendons removed at operation and 45 foreign bodies in 950 tendon samples at autopsy. The foreign material was found to be organic in 29 cases, metal in 20 cases and plastic in six cases. In the others, glass, sand, mineral grease and textiles could be detected. In 33 cases the material could not be identified. The foreign bodies were found in the tendons of the upper extremities in 51 cases and the lower extremities in 47 cases. Foreign bodies in the tendons were more likely to cause problems in the upper limbs than in the lower limbs: these problems were purulent tendonitis, necrosis, foreign body granuloma, fibrosis and peritendonitis and calcification.

Histochemical and histophysical detection and specification of foreign bodies in human tissues.

The authors summarize their experience from histochemical and histophysical detection of foreign bodies in 1,000 cases. Methods are described for the detection of metal particles, vegetable material, of mineral substances, plastics, and mineral greases.

Quantitative alterations of intramuscular connective tissue in calf muscles of the rat during combined hypoxia and hypokinesia.

The investigations were designed to study the long-term effect of hypoxia, hypokinesia and of combined hypokinesia and hypoxia on the skeletal muscle in the rat. In the muscles of the hypoxic and hypokinetic animals serious degenerative changes were found and the fibre-type ratio was altered. In the hypoxic animals moderate fibrosis was revealed. In the hypokinetic, and hypokinetic + hypoxic animals the amount of connective tissue was 5 to 10-fold greater in the calf muscles as compared to the control.

Immunopathological study on palmar aponeurosis in Dupuytren's disease.

The authors examined the immunological and immunohistochemical alterations of palmar aponeurosis in Dupuytren's contracture. In the IgG-content no difference were found between the intact and diseased aponeurosis. The mean of IgA content was 2 fold, the IgM content 3 fold higher in Dupuytren's aponeurosis than in normal ones. The immunoglobulin containing cells localised around the Dupuytren's nodules and in fibrotic, but not nodular parts of aponeurosis. Extracellular immunoglobulin deposits were not found.

Fine structural alterations of the palmar aponeurosis in Dupuytren's contracture. A combined scanning and transmission electronmicroscopic examination.

The authors examined the fine structural alterations of palmar aponeurosis in Dupuytren's contracture. Two types of the fibroblasts can be identified: classic fibroblasts and myofibroblasts. In the Dupuytren's tissue one fourth of all non-inflammatory cells were regarded as myofibroblasts. In the Dupuytren's aponeurosis the orientation of the thin and thick collagen fibers varied. The Paccini corpuscles were hypertrophised and around them compact collagen tissue was increased.

Histochemical and biochemical alterations in skeletal muscles of rats during combined chronic hypoxia and hypokinesia.

This investigation was designed to study the long term effect of combined hypokinesia and hypoxia on the skeletal muscle. In the muscles of the hypoxic and hypokinetic animals, serious degenerative changes were found and the fibre type ratio was alterated. The malate dehydrogenase activity was decreased, and both LDH and MDH isoenzymes pattern were alterated.

Ultrahistochemical localization of the glutamate-oxaloacetate transaminase (GOT) enzyme in hepatic and skeletal muscle cells in rat.

The ultrastructural localization of the glutamate-oxaloacetate transaminase (GOT) enzyme in hepatic and skeletal muscle cells has been studied. The GOT activity localized first on the cristae of mitochondria both in hepatic and skeletal muscle cells. Further activity of the enzyme was observed in the endoplasmic reticulum and in sarcoplasmic reticulum but not in other cell components.

Ultrastructural changes in human liver cells due to reversible acute hypoxia.

The ultrastructural alterations in human liver cells have been studied in reversible acute hypoxia. After thoracic and/or craniocerebral injury, the arterial oxygen saturation was under 60 mm Hg, and the circulation was intact, in all 20 patients. The hepatic cells were characterized by depletion of glycogen, swelling of the mitochondria with some irregularity of their membranes, and swelling of the endoplasmic reticulum, as well as by the appearance of large hypoxic vacuoles.

Fibre composition of human hand and arm muscles.

The fibre composition of 5 hand and 3 arm muscles were investigated by histochemical methods. The hand muscles of the dominant side (right side by the right-handed and left side by the left-handed persons) had a significantly higher amount of type 2 fibre than type 1 fibre. In the same subjects the fibre composition of the 3 investigated arm muscles were practically the same on the dominant and on the non-dominant side. It is suggested that the different movements of the dominant hand causes the difference in the fibre ratio of the hand muscles, while the different mechanical demands did not influence the composition of the arm muscles.

Oxygen and carbon dioxide tensions in calf muscles of rat.

The oxygen and carbon dioxide tension were studies with Silastic tonometer technique in skeletal muscle and subcutaneous tissue of rat. The high initial pO2 was caused by airborne contamination during implantation and declined rapidly. Tissue gas tensions measured with a Silastic tonometer reflect the healing sequences of implantation trauma and stable readings are not obtained until 14 days after implantation. After healing of implantation injury 42 to 47 mmHg pO2 and 50 to 57 mmHg pCO2 were measured in muscle and 23 to 26 mmHg pO2 and 51 to 57 mmHg pCO2 in subcutaneous tissue of rat.

Alterations of oxygen and carbon dioxide tensions in crush-injured calf muscles of rat.

The alterations of oxygen and carbon dioxide tensions in crush-injured muscles were determined by means of a Silastic-tonometer. Immediately after crush-injury the oxygen tension was elevated, then declined and 2 hours after trauma a value of 10 to 14 mmHg was reached. The oxygen tension was 8 to 15 mmHg the next four days after injury, from 5th day the tissue pO2 elevated rapidly. On 14th day the tissue oxygen tension was 60-72 mmHg, thereafter decreased gradually to 40-50 mmHg by the 19th day. The tissue pCO2 elevated within 2 hours after injury to 95-105 mmHg. From 5th day decreased gradually to 50 mmHg by the 21st day.

Enzyme histochemical alterations in human skeletal muscles after tenotomy and after spontaneous rupture of the tendon.

The authors studied the histochemical alterations of human skeletal muscles after tenotomy and after spontaneous rupture of the tendon. Both succinate dehydrogenase (in type I fibers), and myofibrillar ATP-ase (in type 2 fibers) activity was decreased in all injured muscles. In the intact antagonists and contralateral muscles alterations were not found. The creatine phosphokinase and aldolase activity were decreased also in injured muscles. The lactate dehydrogenase activity was various both in affected and in unaffected muscles. Two weeks or more after the injury of the tendon in injured muscles the number of type 1 fibers were decreased and therefore a mathematically significant type 2 fibre predominance occurred. Atrophy involve both type 1 and type 2 fibers, but type 1 fibre atrophy was more pronunced as type 2 fibre atrophy.