A nitric oxide-sensitive electrode: requirement of lower oxygen concentration for detecting nitric oxide from the tissue.

In order to directly detect nitric oxide (NO) liberated from isolated tissue, a practical and convenient method using a nitric oxide-sensitive electrode is described. To avoid the nonselective signal caused by ionic substances, the electrode was covered with three layers but remains permeable for gaseous substances. In a solution bubbled with 20% oxygen (pO2, approximately 150 mm Hg), administration of S-nitroso-N-acetyl-d, l-penicillamine (SNAP) at concentrations greater than 10(-7) mol/L elicited an electrode response. Based on a comparison with the chemical determination of NO released from SNAP, the electrode may be able to detect nitric oxide around nmol/L. At least 30 nmol NO per liter in anoxic conditions was reported to be detected by this electrode (Matsui, 1995). In a specially designed small chamber, the electrode was attached on the surface of endothelial side of the isolated aorta of the guinea pig. When carbachol was added to the chamber, the electrode responded when the solution was bubbled with 20% but not with 40% or 95% of oxygen, suggesting a much faster decomposition of nitric oxide in the presence of higher concentrations of oxygen. The electrode response to carbachol was abolished in the presence of NG-monomethyl-L-arginine or nitro arginine. These results suggest that the electrode method described in this manuscript is suitable for detecting nitric oxide liberated from isolated tissues when comparatively low oxygen levels are present in the physiological salt solution.

[Evaluation of thrombomodulin and tumor necrosis factor-alpha levels in patients with hemolytic uremic syndrome caused by enterohemorrhagic Escherichia coli O157:H7 infection].

To investigate the role of thrombomodulin (TM) and tumor necrosis factor-alpha (TNF-alpha) in hemolytic uremic syndrome (HUS), serum and urinary levels of TM and TNF-alpha were determined in patients with hemorrhagic enterocolitis (HC) of enterohemorrhagic E. coli O157:H7 infection. These patients were divided into two groups: an HUS group consisting of patients with HUS; an HC group consisting of patients without HUS. In the 10 days after the onset of diarrhea, the serum TM and TNF-alpha levels in the HUS group were significantly elevated compared with those in the control group but decreased after 11 days. The serum TM and TNF-alpha levels in the HC group were not elevated compared with those in the control group except for one case of TNF-alpha. It is suggested that the serum TM elevation showed the severity of endothelial cell damage. Urinary TM and TNF-alpha levels in the HUS group were significantly elevated in the first 10 days. The urinary TNF-alpha levels rapidly decreased after 11 days, while the urinary TM levels were persistently high. From these results, the sustained elevation of the urinary TM levels suggested the persistent presence of renal endothelial cell damage, and the decrement of urinary TNF-alpha levels suggested that TNF-alpha acted as a trigger of the renal endothelial cell damage in the first 10 days.

[Influence for cultured renal cell growth ability by toxins of Escherichia coli].

There have been many reports indicating that Escherichia coli from pyelonephritis may exhibit several specific phenotypes. The purpose of the present study was to examine the effects of various toxins from Escherichia coli on cultured renal cell growth. alpha-hemolysin suppressed growth of Mardin Darby canine kidney (MDCK) cells in a dose-dependent manner. A low dose of O-antigen suppressed MDCK cell growth, while a high dose of the antigen increased the cell growth slightly. K:1-antigen had no effect on MDCK cell growth. Mesangial cell growth was not affected by alpha-hemolysin. A significant increase in mesangial cell growth was recognized by the O- or K:1-antigen. From these results it can be speculated that alpha-hemolysin from Escherichia coli may play a leading role, and O- or K-antigen may play a supporting role in the pathogenesis of pyelonephritis.

[A case of Bufferin induced acute interstitial nephritis--analysis of immune cells and cytokine].

This paper describes a case report of acute interstitial nephritis associated with Bufferin. A 15-year-old girl were referred to our hospital due to fever and renal dysfunction. Laboratory findings showed elevation of serum BUN and creatinine, and increased urinary beta 2-MG excreation. Light microscopic findings of her renal biopsy specimen revealed edema and numerous inflammatory cells in the interstitium, and minor alterations in glomeruli. The interstitial infiltrates consisted mainly of T cells and also monocytes/macrophages. Interstitial cells were labelled with antibodies to interleukin (IL)-1 and tumor necrose factor (TNF). Bufferin was positive by lymphocyte stimulation test. Thus, we considered that this drug was causative in this case. This observation suggests the participation of cell-mediated immune injury in drug induced acute interstitial nephritis.

Tertiary peptide bond containing-oligo(Leu)s. Conformational studies in solution of oligo (L-leucine)s with L-proline residue and glycyl-N-(2, 4-dimethoxybenzyl)-L-leucine sequence.

In order to elucidate the role of tertiary peptide bonds in the conformational development and solubility improvement of peptides, the conformational properties of oligo(Leu)s with the Pro residue and the Gly-(Dmob)Leu sequence were investigated in solution using i.r. absorption, CD, and molar rotation measurements. The i.r. absorption spectroscopy indicated that the peptides soluble in inert solvents such as CCl4 and toluene had a predominantly beta-sheet structure in these solvents. The conformations of the peptides in CCl4 and toluene were essentially the same as those in a solid state, whereas in THF and in MeOH, the peptides examined were efficiently subjected to solvation, and a randomly coiled structure was predominant. In order to confirm the randomly coiled structure, measurements have been made of the molar rotations of the peptides in a variety of strong proton acceptor and donor solvents. CD measurements are also carried out in MeOH. Through the investigations, it was shown that the protection of peptide bonds and the insertion of the Pro residue had the same effect on conformational and solubilizing behaviors and induced onset of an unordered structure and easy solvation of the peptides in medium and high polarity-solvents.

Overexpression of bcl-2 in transient abnormal myelopoiesis associated with Down syndrome.

Transient abnormal myelopoiesis (TAM) is a haematological complication found in Down syndrome. To determine the mechanisms of sustained proliferation of TAM cells, we studied the expression of apoptosis-related proteins, such as bcl-2, Fas (APO-1/CD95) and p-53, in peripheral blood cells from a new-born infant with Down syndrome and TAM. Using flow cytometry, peripheral blood mononuclear cells (PBMCs), consisting mostly of blast cells, showed marked expression of bcl-2 protein but not of Fas or p-53 products. DNA gel electrophoresis of PBMCs, cultured in the absence of serum factors, revealed no marked fragmentation. Our findings suggest that bcl-2 overexpression may be associated with prolonged cell survival of TAM cells.

Clinical and radiological features in four adolescents with nutcracker syndrome.

We describe four adolescents with the nutcracker syndrome. In three patients, the nutcracker syndrome was detected through mass urinary screening; the other patient was diagnosed after a sudden onset of dark urine. All patients underwent magnetic resonance angiography (MRA) for diagnosis of the nutcracker syndrome, which revealed dilatation of the left renal vein ranging between 7.4 and 13 mm at the hilar portion. A renal biopsy, performed in three patients, showed no remarkable abnormalities in the glomerulus or tubulointerstitial tissue. The patients complained of physical discomfort, including headache, abdominal pain, fainting, and tachycardia mimicking clinical symptoms of an orthostatic disturbance. However, no chronic systemic diseases were detected in any of the patients after repeated laboratory examinations. An orthostatic disturbance preceded diagnosis in three patients. This report indicates that the nutcracker syndrome may cause serious physical ailments that clinically mimic an orthostatic disturbance. It may be important to identify the nutcracker syndrome among children who manifest non-specific physical complaints. MRA could be a safe and reliable method for diagnosing the nutcracker syndrome.