Viral gene mutation as determinant of low grade malignancy of lesions induced by perinatal retrovirus infection

Of 108 Wistar/Ma rats perinatally injected with Snyder-Theilen feline sarcoma virus, 75 developed tumors within 60 days (group A), and 25 after more than 117 days (group B). Metastases were detected in 59.1% and 11.8% in group A and B respectively. Antibody to v-fes gene product was found to occur before tumor development in group B and after tumor development in group A. v-Ses was found to be down-regulated and extensively mutated in tumors of group B. These results suggest viral gene mutation as a determinant of low grade malignancy of lesions induced.     

Characterization of connectin-like proteins of obliquely striated muscle of a polychaete (Annelida)

Summary In obliquely striated muscle of polychaete, Neanthes sp., three kinds of connectin (titin)-like high molecular weight proteins, 4000 kDa, 1200 kDa and 700 kDa, were detected by SDS gel electrophoresis and immunoblots using antibodies to vertebrate skeletal muscle connectin and antiserum to the protein in question. The 700 kDa protein was isolated and characterized as a sheet-rich filament 170 nm long and 4 nm wide. Using polyclonal antibodies to the 700 kDa protein, the binding of the immunogold to the thick filament was only demonstrated in high ionic strength relaxing solution which solubilized some myosin. This observation suggested that the 700 kDa protein was localized below the layers of myosin in the thick filament and this localization is different from that of twitchin of C. elegans bodywall muscle that is on the surface of thick filament. The 4000 kDa protein was identified as a very thin filament linking the thick filament to the dense body. The very thin filaments were visualized in gelsolin-treated actin filament-free fibres. The 1200 kDa protein was located in the periphery of the dense body. A model of the elastic filament in polychaete bodywall muscle is presented.     

A Simple and Rapid Fluorometric Determination Method of α1-Acid Glycoprotein in Serum Using Quinaldine Red

We examined different fluorescent probes suitable for fluorometric determination of ₁-acid glycoprotein (AGP) in serum. Quinaldine red (QR) was shown to bind strongly and selectively to AGP. Taking advantage of the enhanced fluorescence of QR in the presence of AGP, we developed a direct method for the determination of serum AGP without removal of other serum proteins such as albumin. AGP concentrations in serum of healthy volunteers and patients correlated well with results from the conventional single radial immunodiffusion (SRID) method (r = 0.93, slope = 1). The newly developed method is faster and has a larger analytical concentration range than the SRID method. This method can also be used to determine AGP in serum of experimental animals, and it can serve to monitor AGP serum concentrations for pharmacokinetic evaluation of basic drugs.     

A new model rat with acute bronchiolitis and its application to research on the toxicology of inhaled particulate matter

The aim of the present study was to establish a useful animal model that simulates humans sensitive to inhaled particulate matter (PM). We have developed a new rat model of acute bronchiolitis (Br) by exposing animals to NiCl2 (Ni) aerosols for five days. Three days following the Ni exposure, the animals developed signs of tachypnea, mucous hypersecretion, and bronchiolar inflammation which seemed to progress quickly during the fourth to fifth day. They recovered from lesions after four weeks in clean air. To assess the sensitivity of the Br rats to inhaled particles, two kinds of PM of respirable size were tested with doses similar to or a little higher to the recommended threshold limit values (TLVs) for the working environment in Japan. Titanium dioxide (TiO2 = Ti) was chosen as an inert and insoluble particles and vanadium pentoxide (V2O5 = V), as a representative soluble and toxic airborne material. The Br rats exposed to either Ti or V were compared the pathological changes in the lungs and the clearance of particles to those in normal control or Br rats kept in clean air. The following significant differences were observed in Br rats: 1. delayed recovery from pre-existing lesions or exacerbated inflammation, 2. reductions in deposition and clearance rate of inhaled particles with the progress of lesions. The present results suggest that Br rats are more susceptible to inhaled particles than control rats. Therefore, concentrations of particulate matter lower than the TLVs for Japan, which have no harmful effects on normal lungs, may not always be safe in the case of pre-existing lung inflammation.     

Bone marrow transplantation attenuates murine IgA nephropathy: role of a stem cell disorder

BACKGROUND: The pathogenesis of IgA nephropathy is still obscure. The aim of this study was to investigate whether the fundamental pathogenesis of IgA nephropathy lies in bone marrow stem cells (BMCs). METHODS: We used donors of two different strains for bone marrow transplantation (BMT) into mice with a high content of serum IgA (ddY strain, HIGA mice), a murine model of IgA nephropathy. One group (B6-->HIGA, N = 5) received BMCs of C57BL/6j (B6) mice, and the other (HIGA-->HIGA, N = 8) were reconstituted with BMCs of HIGA mice. RESULTS: Twenty-six weeks after BMT, in B6-->HIGA mice, mesangial deposits of IgA and C3 were statistically milder than those in HIGA-->HIGA mice. Light microscopic observations disclosed that glomerular sclerosis and mesangial matrix expansion in B6-->HIGA mice were decreased compared with those in HIGA-->HIGA mice. These B6-->HIGA mice also excreted less urinary albumin than HIGA-->HIGA mice. Furthermore, serum levels of IgA in B6-->HIGA mice were markedly lower than those in HIGA-->HIGA mice. Size analysis of serum IgA revealed that macromolecular IgA were notably lower in B6-->HIGA mice than in HIGA-->HIGA mice. CONCLUSIONS: Our results suggest that qualitative and quantitative changes of serum IgA are determined at the level of stem cells, and that BMT from normal donors can attenuate glomerular lesions in HIGA mice. This approach may offer a new avenue to study the pathogenesis of IgA nephropathy.     

A preliminary study of microcapsule suspension for hemolysis evaluation of artificial organs

A microcapsule suspension, a substitute for animal blood in hemolysis tests, has been developed for evaluation of the absolute hemolytic properties of circulatory artificial organs. The microcapsule suspension was made by dispersing microcapsule slurry into an ethylene glycol sodium chloride solution. The microcapsule slurry was composed of a leuco dye solution and polyurethane membrane made by the reaction between aliphatic poly-isocyanate and polyamine by interfacial polycondensation. The microcapsule was a small particle containing dye inside. The microcapsule suspension was white; the diameter of the microcapsules was from 5 to 100 microns. The specific gravity of the suspension was 1.024, and the membrane was elastic. The fluid showed Newtonian characteristics, different from animal blood, and its viscosity was approximately 5.8 mPa.s. After the microcapsules were destroyed, the leuco dye was extracted with n-hexane from the suspension and was measured by spectroscopy after being colored with acid ethanol. Hemolysis can be regarded as a fatigue fracture of cell membranes rather than a static fracture. The destruction of microcapsules by a Potter type tissue grinder was observed at a low stroke number region and was compared to rat blood. Moreover, hemolysis tests of a commercially available centrifugal blood pump and the prototype of our centrifugal pump for mechanism checks were carried out with bovine blood. The hemolysis level of the prototype pump increased with time while the hemolysis level of the commercial blood pump did not change as much as that of the control when both pumps were tested with the microcapsule suspension. These results are similar to tests utilizing bovine blood. Therefore, hemolysis tests of circulatory artificial organs completed with microcapsule suspension are expected to provide results similar to tests with animal blood.     

Reduction of post-ischemic lung reperfusion injury by fibrinolytic activity suppression

BACKGROUND: Although extensive studies on the detailed mechanisms of ischemia-reperfusion injury have been conducted, the implication of the fibrinolytic system has not been known. To determine the role of the fibrinolytic system in ischemia-reperfusion injury, we used tranexamic acid, a synthetic specific plasmin and tissue-type plasminogen activator inhibitor, to suppress fibrinolytic activity in a rabbit lung ischemia-reperfusion model. METHODS: New Zealand White rabbits were randomly divided into two groups: a simple ischemia group and a group injected with tranexamic acid before left hilar occlusion. After 2 hours of warm ischemia, plasma was collected from pulmonary vessels. Fibrin zymography was used to ascertain fibrinolytic activity, and enzyme-linked immunosorbent assay was used to determine soluble thrombomodulin levels as a marker for endothelial cells damage. Changes in left pulmonary function including arterial oxygen tension, peak airway pressure, and pulmonary vascular resistance were recorded during reperfusion after the 2 hours of warm ischemia. RESULTS: Fibrinolytic activity and soluble thrombomodulin levels increased in the vessels of the ischemic lung, indicating endothelial cell injury. The increased fibrinolytic activity and the rise in soluble thrombomodulin were suppressed by the preadministration of tranexamic acid, resulting in remarkably improved pulmonary function during reperfusion. After 2 hours of reperfusion, the wet-to-dry weight ratios and histological studies showed reduced pulmonary edema in the group that had received tranexamic acid. CONCLUSION: These findings suggest that the fibrinolytic system is involved in the onset mechanism of ischemia-reperfusion injury through induced endothelial cell damage and increased vascular permeability.     

Pigmentation on anterior chamber angle in eyes of patients with atopic dermatitis

PURPOSE: To evaluate pigmentation on the anterior chamber angle in patients with atopic dermatitis. METHODS: This study includes 61 patients suffering from atopic dermatitis who visited our hospital between 1991 and 1995. Gonioscopy, cycloscopy, and fundus examinations with a scleral depressor were performed on every patient during the initial visit, and were repeated every 6 months. Pigmentation on the anterior chamber angle was classified according to Scheie. RESULTS: The pigmentation on the anterior chamber angle at the initial visit was evaluated as grade 0 (15 eyes), grade 1 (81 eyes), grade 2 (21 eyes), and grade 3 (5 eyes). Retinal detachment was found in 9 eyes of the 26 eyes with grade 2 or 3 pigmentation, but in only one of the 96 eyes with grade 0 or 1. The pigmentation on the anterior chamber angle correlated significantly with the incidence of retinal detachment (P < .0001). Causative breaks were found in the peripheral retina or ciliary epithelium in all eyes. CONCLUSIONS: Moderate to dense pigmentation on the anterior chamber angle in patients with atopic dermatitis seems to be a sign of breaks in the retina or ciliary epithelium, and the fundus of these patients should be examined carefully for signs of retinal detachment.