Dextran-magnetite complex: conformation of dextran chains and stability of solution.

Three kinds of dextran-magnetite (DM) complexes were prepared using alkali-treated dextrans with molecular weights of 1900, 4200 and 9600, respectively. The number of dextrans binding to a magnetite core was determined. The number was proportional to the area of core surface and the area occupied by a dextran was 2.

Dextran-magnetite complex: temperature dependence of its NMR relaxivity.

The NMR relaxivity of proton by dextran-magnetite (DM) complex was examined at temperatures from 20 to 80 degrees C. The decrease in T1 relaxivity with increasing temperature is due to the thermal activation of motion of water molecules in and/or surrounding DM particle. The decrease in magnetization of magnetite core is the secondary effect.

Characterization of a temperature-sensitive influenza B virus mutant defective in neuraminidase.

ts5, a temperature-sensitive mutant of influenza B virus, belongs to one of seven recombination groups. When the mutant infected MDCK cells at the nonpermissive temperature (37.5 degrees C), infectious virus was produced at very low levels compared with the yield at the permissive temperature (32 degrees C) and hemagglutinating and enzymatic activities were undetectable.

Observation of 100 nm periodic fibrils in mouse corneal stroma by cryoultramicrotomy.

We observed mouse corneal stroma after treatment with 20 mM adenosine 5'-triphosphate (ATP), thin-sectioned by cryoultramicrotomy, with a transmission electron microscope. A wide array of 100 nm periodic fibrils (100 nm PFs) was observed among D-periodic collagen fibrils. By indirect immuno-cryoultramicrotomy with anti-type VI collagen antibody, immunogold particles were located on 100 nm PFs, indicating that 100 nm PFs were composed of type VI collagen.

Gamete development in Plasmodium berghei regulated by ionic exchange mechanisms.

Ionic regulation in the induction of exflagellation of Plasmodium berghei was investigated by culturing the parasites in various isotonic media. Of the salts tested, NaHCO3 exhibited the highest activity in inducing exflagellation, whereas KHCO3 showed no activity. In the absence of HCO3-, media containing monovalent cation (Na+, K+, Cs+, Rd+, choline+, lysine+, arginine+) and Cl- also induced exflagellation, but their activities were lower than that of NaHCO3.

Application of cryo-sapphire knife in rapid frozen ultrathin sectioning for electron microscopy.

Conventional sectioning of frozen and fixed tissues is usually performed using the glass knife. Although the glass knife is economical, it has several disadvantages. In this study, the Authors have examined the sectioning quality of the sapphire knife in frozen tissues as an alternative to the glass knife.

Light- and electron-microscopical study of a case of gold salt-induced hepatotoxicity.

A 56-yr-old woman with long-standing rheumatoid arthritis exhibited jaundice, pruritus and abdominal discomfort after 8 yr of periodic gold sodium thiomalate injections amounting to a cumulative dose in excess of 2.5 gm. Histopathological examination of the liver biopsy specimen showed submassive loss of parenchyma, collapse of reticulin and mixed cellular inflammatory infiltrates.

Identification of hemolytic granules isolated from human myocardial cells.

Human myocardial cells from fresh autopsy material contained granules which possessed hemolytic activity against guinea pig and rabbit erythrocytes. The hemolytic granules, which had a density of 1.02 and a diameter of 200-300 nm, were recovered as a microsome fraction from subcellular homogenates of human myocardial cells by differential centrifugation in 300 mM sucrose containing 0.

An electron microscopic and electron probe study of the microcirculation in cold-induced oedema.

An ultrastructural study of adult mongrel dogs and cats was made to evaluate the changes in the microcirculation during cerebral oedema formation. Two to five cold injuries were made in one hemisphere in dogs and one lesion was made in cats. In several dogs arterial hypertension was induced with a balloon in the aorta.

Penetration and stainability of modified Sato's lead staining solution.

The penetration and stainability of modified Sato's lead staining solution containing calcined lead citrate were studied. Modified Sato's lead solution was preserved for 1 week and for 2 years, each at room temperature and at 4 degrees C. Specimens were stained with these solutions to measure the stainability.

Structural study of immunoaffinity-purified DNA polymerase alpha-DNA primase complex from calf thymus.

The DNA polymerase alpha-DNA primase complex was purified over 17,000-fold to near homogeneity from calf thymus using an immunoaffinity column. Sodium dodecyl sulfate gel electrophoresis revealed three polypeptides with molecular weights of 140, 50 and 47 kDa, in a ratio of 1:2:0.25.

Transcriptive complex of Newcastle disease virus. II. Structural and functional assembly associated with the cytoskeletal framework.

The transcriptive complex, the nucleocapsid with the viral RNA-synthesizing activity, of Newcastle disease virus (NDV) contains three protein components, the major structural subunit (NP) and two associated proteins (P and L) involved in the RNA synthesis. We studied the pathway of these proteins from synthesis to assembly into the complex by pulse-chase labeling of infected cells followed by detergent extraction of the cells to separate soluble and cytoskeletal fractions. Most molecules of NP and P (and probably L) became associated with the cytoskeletal framework immediately after their synthesis.

An association of mercury with selenium in inorganic mercury intoxication.

Energy dispersive X-ray analysis was performed on the renal tubular cells of two patients with inorganic mercury intoxication. Some lysosomes of these cells consisted of unusual matrices of aggregated electron-dense grains which were positive for mercury, selenium and sulphur. Though maps of the specific X-rays of both mercury and selenium coincided exactly with these lysosomes, the molecular ratio of selenium to mercury ranged between zero and 2.

Electron probe X-ray analysis on human hepatocellular lysosomes with copper deposits: copper binding to a thiol-protein in lysosomes.

Livers of eight patients with chronic liver diseases were investigated by energy dispersive x-ray analysis. First, three kinds of preparations (osmium-Epon sections, glutaraldehyde-frozen sections, and unfixed-frozen sections) were compared for element detectability at a subcellular level. The glutaraldehyde-frozen sections were satisfactory as far as copper, sulfur, and phosphorus were concerned.

Effects of dantrolene and methylxanthines on the sensory nerve terminal of the frog muscle spindle.

The application of 1.5-4 microM dantrolene decreased the threshold and the current sensitivity of the rhythmic hyperpolarizations that occur during depolarization of the sensory nerve terminal in the frog muscle spindle. The higher concentration provoked spontaneous rhythmic changes even without depolarization.

Malignant transformation and viral replication of rat bone and muscle cells after in vitro infection with rat-adapted murine sarcoma virus (Moloney).

Isolated bone and muscle cells from rat fetuses were infected with the rat-adapted osteosarcomogenic murine sarcoma virus (Moloney) for examination of malignant transformation and viral replication. After the infection, the bone cells underwent an unusual transformation characterized by two patients in the focus formation. In the early transformation (Transformation I), foci consisting of only morphologically altered cells appeared, but they soon disappeared.

Attempts to induce tubular deformations and subsequent mixed tumours from organotypic cultures of mouse renal mesenchyma.

With the aim of expanding knowledge on the pathogenesis of nephroblastomata, an embryological organ culture system (Grobstein, 1956) was tested for its applicability to in vitro carcinogenesis experiments by using murine sarcoma virus (MSV-M) and 3-methylcholanthrene (MCA). Treatment of CBA/H-T6 mouse metanephrogenic mesenchyma with MSV-M at the pretubular stage neither disturbed the glomerulogenesis nor induced rapid malignant transformation. Treatment of the same tissues with MCA considerably inhibited the glomerulogenesis but failed to also reduce rapid malignant transformation.