HISTOPATHOLOGICAL STUDIES ON THROMBOTIC MICROANGIOPATHY WITH SPECIAL REFERENCES TO THREE CASES ASSOCIATED WITH ACUTE PROMYELOCYTIC LEUKAEMIA

Five autopsy cases of thrombotic microangiopathy, including 3 cases associated with acute promyelocytic leukaemia, were examined macroscopically, light-and electronmicroscopically.
The so-called hyaline thrombi In thrombotic microangiopathy were composed of fibrin and its degenerative products. Thrombocytes and other blood cells were not seen in the thrombi.
At the site of the formation of a thrombus, there was no conspicuous change in the walls of the capillaries and arterioles. It was considered, therefore, that the intravascular deposition of fibrin was the primary event in the development of thrombotic microangiopathy.
In regard to the distribution and morphologic findings, there was no basic difference between the microthrombi in cases associated with acute promyelocytic leukaemia and those without it.
The bone marrow and some other organs in cases of thrombotic microangiopathy associated with acute promyelocytic leukaemia macroscopically revealed a green colour. Many thrombi composed of leukaemic cells and fibrin were found in the pulmonary arteries of these cases. Furthermore, prominent erythrophagocytosis in the bone marrow and lymph nodes was a common finding in these cases.     

Comparative studies with various substrains of Mycobacterium bovis BCG on the production of an antigenic protein, MPB70.

A protein, isolated and purified from the unheated culture filtrate of Mycobacterium bovis BCG (substrain Tokyo 172) and designated MPB70, elicited a delayed skin reaction in guinea pigs sensitized with viable cells of BCG but not in those sensitized with heat-killed cells. The skin reaction reached the maximum 4 to 8 weeks after the inoculation of the BCG and then decreased gradually, resulting in conversion to negative after 20 weeks, whereas the skin reaction to purified protein derivative (PPD) continued to be positive. Guinea pigs immunized with viable cells of various substrains of BCG were skin tested with MPB70 and PPD. Guinea pigs immunized with the BCG substrain Tokyo 172 and the substrain Moreau (Brazil) showed strong delayed skin reactions to both MPB70 and PPD. On the other hand, guinea pigs immunized with the Pasteur substrain 1173P2, the Glaxo substrain 1077, the Copenhagen substrain 1331, the Tice substrain, or the Beijing substrain 64-42 showed negative skin reactions to MPB70, whereas they were strongly positive to PPD. In a two-dimensional acrylamide gel electrophoretic analysis of proteins from the culture filtrates of the BCG substrains, the culture filtrates of the Tokyo and Moreau substrains showed the spot of MPB70 on the gel slabs, whereas those of the other BCG substrains did not.     

Activation of precursors to both glycoproteins of Newcastle disease virus by proteolytic cleavage

With strain Ulster of Newcastle disease virus, two precursor glycoproteins, HN₀ and F₀, were identified; these are converted by proteolytic cleavage into glycoproteins HN and F, respectively. Purified virions containing predominantly glycoproteins HN₀ and F₀ together with a small amount of HN are not hemolytic and have reduced levels of hemagglutinating and neuraminidase activity and of infectivity. After in vitro treatment with the appropriate proteolytic enzymes, biological activities are fully expressed in these particles. The precursor glycoprotein HN₀ was isolated and found to be largely devoid of hemagglutinating and neuraminidase activities. High levels of both activities were present, however, when this material was subjected to proteolytic cleavage. These observations demonstrate that cleavage is a precondition for the biological activity not only of glycoprotein F but also of glycoprotein HN. There is a striking difference between glycoproteins HN₀ and F₀ with repsect to their susceptibility to proteolytic enzymes. Cleavage and activation of HN₀ can be accomplished by a variety of proteases, such as chymotrypsin, elastase, thermolysin, and trypsin. In contrast, F₀ shows a specific requirement for trypsin.     

Three antigenic variant groups in human respiratory syncytial virus subgroup B isolated in Japan

Summary Nineteen hybridomas producing monoclonal antibodies (MAbs) against the structural proteins of strain 58–17, a subgroup B field strain of respiratory syncytial virus (RSV) isolated in Japan, were obtained by fusion of X 63 myeloma cells with spleen cells from BALB/c mice immunized with the virus-infected HEp-2 cells. Seven clones were found to produce antibodies against the fusion protein (F), five against the large glycoprotein (G), five against the nucleoprotein (NP) and two against the 22k protein by radioimmunoprecipitation assay. By competitive binding assay with the MAbs, at least seven, two, three and one epitopes were defined on the F, G, NP and 22k protein components of subgroup B strain, respectively. Of these epitopes, three, two and one epitopes on the F, G and NP components were different from subgroup A strain, respectively. Fifty-three other field strains of subgroup B isolated in Sapporo, Japan, during nine epidemic years from 1980 to 1989, were examined for reactivity with the MAbs by ELISA. Different reactivity to one anti-NP antibody suggested that the 53 strains can be divided into three groups (B-a: 26 strains, B-b: 26 strains, and one other strain). The dominant strain prevailing during the 1984 to 1988 epidemic years had changed from B-a to B-b. All of the 53 subgroup B strains reacted similarly with the other 18 MAbs.     

Immunochemical characterization of mouse brain-associated theta (Thy-1) antigen.

The Thy-1 antigens or rat brain and thymus have been isolated and chemically characterized, but those of mice have not been identified. Moreover, it is uncertain whether the antigens are glycolipids or glycoproteins. This study with highly purified preparations of gangliosides GM₁, ¹GD_1a, GD_1b and GT_1b from bovine brain and several ganglioside fractions from mouse brain showed that Thy-1 activity does not reside in gangliosides, but rather in the chloroform-methanol-insoluble residue of brain remaining after extraction of gangliosides. The antigen could be solubilized from this residue with a non-ionic detergent. The antigenic activity of the solubilized preparation was heat-labile but resistant to periodate. The chemical properties of the Thy-1 antigen of mouse brain are discussed.     

Induction of fibroblast-like cells from CD34(+) progenitor cells of the bone marrow in rheumatoid arthritis

To assess the role of bone marrow in the pathogenesis of rheumatoid arthritis (RA), we examined the capacity of CD34(+) cells from bone marrow to generate fibroblast-like type B synoviocytes. CD34(+) cells from the bone marrow of 22 RA patients differentiated into cells with fibroblast-like morphology, which expressed prolyl 4-hydroxylase, in the presence of stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha), much more effectively than CD34(+) cells from bone marrow of 15 control subjects (10 patients with osteoarthritis and 5 healthy individuals). The generation of fibroblast-like cells was not at all observed in cultures with SCF, GM-CSF, and interleukin 4 (IL-4) with or without TNF-alpha. Generation of fibroblast-like cells was correlated with matrix metalloproteinase (MMP)-1 levels in culture supernatants. Thus, MMP-1 levels were significantly higher in TNF-alpha-stimulated cultures of bone marrow CD34(+) cells from patients with RA than in those from the control group. These results indicate that bone marrow CD34(+) cells from patients with RA have abnormal capacities to respond to TNF-alpha and to differentiate into fibroblast-like cells producing MMP-1, suggesting that bone marrow CD34(+) progenitor cells might generate type B synoviocytes and thus could play an important role in the pathogenesis of RA.     

New algorithmic-based digital filter processing system for real-time continuous blood pressure measurement and analysis in conscious rats

A new algorithmic-based digital filter processing system for real-time continuous blood pressure (BP) measurement and analysis in freely-moving conscious rats has been developed. Real-time recognition of BP waveforms, real-time noise rejection and determination of representative waveform indexes (WIs) at indicated time points using digital filters and Smirnov's rejection test were realized with this system. Digital filters were applied for two different purposes: waveform segmentation and smoothing the calculations of representative WIs. Smirnov's rejection test was used for real-time noise rejection and yielded an accurate rejection rate of 99.99%. The result was that the digital filter processing and Smirnov's rejection test realized accurate real-time BP measurement and analysis in freely-moving conscious rats using a personal computer.