Potentiation and restitution of heart muscle contraction in rats adapted to exercise

The original amplitude of contraction of strips of myocardium determined the inotropic response to paired stimulation. The higher the initial amplitude, the lower the degree of potentiation and the higher the degree of restitution of contraction. For equal amplitude, the degree of potentiation of myocardial contraction of exercise-adapted rats was greater and the degree of restitution smaller than in the control. These changes probably reflect changes in the ion transport system of the myocardial cells.Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 780–782, July, 1976.     

RNA tumor virus phosphoproteins: subvirion location of the multiple phosphorylated species.

An analysis of core particles of 1.23 g/cm³ density of the endogenous feline type C virus (RD-114) showed the presence of all of the major low molecular weight structural proteins, namely p30, p12, p10, and the phosphoprotein pp15, in relative proportions similar to those detected in intact RD-114 virions. The protein kinase activity of the virus was also found to be associated with the core. A comparison of the content of multiple phosphorylated species of the pp15 derived from the core with that isolated from the whole virion demonstrated that all major phosphorylated species of RD-114 pp15 were located in the core structure.     

Murine interleukin 5 receptor isolated by immunoaffinity chromatography: comparison of determined N-terminal sequence and deduced primary sequence from cDNA and implication of a role of the intracytoplasmic domain

The murine interleukin 5 receptor (IL-5R) was identified by utilizing an immobilized IL-5 and an immobilized monoclonal antibody against the murein IL-5R (designated H7 mAb). The H7 mAb immunoaffinity-purified materials from the extract of cell-surface radioiodinated T88-M cells (an IL-5-dependent early B cell line) using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) were reacted with an immobilized IL-5 matrix. SDS-PAGE of the adsorbed fraction revealed a single band at approximately 60 kDa. The binding of the 60 kDa protein to the immobilized IL-5 matrix was inhibited by the excess IL-5. The CHAPS-extract depleted of the 60 kDa protein by the absorption with H7 mAb did not contain any IL-5 binding proteins. Immunoaffinity procedure provided a final 7400-fold purification, based on an estimation of the content of the 60 kDa protein (approximate purity: 20%) from the silver-stained pattern of SDS-PAGE. Actin was copurified with the 60 kDa protein at an approximate ratio of 1:1, suggesting that the intracytoplasmic domain of the IL-5R may interact with actin. Furthermore, soluble IL-5R (molecular mass: 50 kDa) was purified by the H7 mAb-immunoaffinity chromatography. The purified soluble IL-5R was capable of inhibiting the binding of IL-5 to T88-M cells. Preparative SDS-PAGE followed by electroblotting onto a membrane permitted the determination of the N-terminal sequence of the IL-5R. The determined N-terminal sequence of the IL-5R and the deduced primary sequence from recently isolated cDNA were compared.     

Inherited aplastic anemia with abnormal clones in bone marrow and increased endoreduplication in peripheral lymphocytes

Cytogenetic studies in peripheral blood and bone marrow cells from a female patient (aged 31 years) with inherited aplastic anemia and without other congenital anomalies are reported. Endoreduplication was increased in stimulated peripheral lymphocytes in several investigations. Chromosome breaks were shown to be near the control frequency, although chromatid exchange figures and dicentrics were present. Cytogenetic analysis was extended to the three children of our patient. Abnormal clones were detected in bone marrow preparations of our patient in all cytogenetic investigations. At the first examination, two of these clones were prevalent, with their karyotypes being 48,XX,+9,+16 and 46,XX,dup(1)(q24→q32),t(17;?)(p12–13;?). The prevailing karyotype after 2 years was 46,XX,t(17;?)(p12–13;?). Involvement of chromosomes #1 and #17 is discussed, taking into account data from the literature concerning several human neoplasias.     

Double minutes and other chromosomal aberrations in two malignant cell lines of the German cockroach Blattella germanica

Structural anomalies of mitotic chromosomes from two tumorigenic cell lines of the German cockroach (Blattella germanica) is described. Aberrations, such as unpairable marker chromosomes, double minutes, di- and tricentrics, ring chromosomes, tri- and quadriradials, and chromosome and chromatid gaps and breaks, were observed in varying proportions. This study reports that the double minute chromosomes (DMs) are associated with insect tumor cells, similar to the findings in both murine and human tumor cells.     

Nasal congestion as a side effect of cromolyn sodium

Cromolyn sodium, a recently introduced antiasthmatic medication, is known occasionally to produce maculopapular and urticarial rashes, and increased bronchospasm. A patient is reported with a previously unpublished side effect of this medication, i.e., severe nasal congestion.     

Effect of interferon on two human choriocarcinoma-derived cell lines

Two cell lines derived from human choriocarcinomas (HCCM-5 and BeWo) are resistant to several biological effects of human interferon such as inhibition of VSV multiplication and inhibition of cell growth, but they develop a normal antiviral activity against EMCV. Nevertheless, in both cell lines, 2-5A synthetase and protein kinase are induced by IFN. 2-5A-dependent endonuclease can be measured by two independent methods and 2-5A itself is detected at least in poly(rI):poly(rC)- and IFN-treated BeWo cells. This is another example of two cell lines that are partially, with respect to the antiviral effect toward VSV, and totally, with respect to the anticellular effect, refractory to IFN treatment, although all the known elements of the 2-5A system are present.