Glutamine Synthetase of the Human Brain: Purification and Characterization

Glutamine synthetase (GS) isolated from human brain formed a single band on sodium dodecyl sulfate-polyacrylamide gel with a molecular weight of 44,000. The enzyme had a specific activity of 179.2 U/mg protein when assayed by measuring the rate of the formation of gamma-glutamylhydroxamate using hydroxylamine as a substrate. In the presence of manganese ions, the relative activity of human brain GS was much lower than that of the sheep brain enzyme. The suppression of activity by increasing the ADP concentration, however, was less marked in the human enzyme than that in the sheep enzyme. Antibodies were raised in rabbits against the purified enzyme. The double-immunodiffusion technique disclosed cross-reactivities among GSs isolated from human, sheep, and rat brains, but the enzymes were not immunologically identical. Immunohistochemically, GS was localized in the cytoplasm of astrocytes in the human and rat brains and in pericentral hepatocytes of the liver.     

Modification of regression of virally xenogenized tumor cells by cyclophosphamide and busulfan

Summary Rat fibrosarcoma cells infected with Friend leukemia virus (FV-KMT-17) grow for a short time and then regress spontaneously in syngeneic hosts. This regression mechanism was examined by analyzing the immunomodulating action of the antitumor drugs busulfan (BU) and cyclophosphamide (CY). In preliminary experiments, the optimum dosages of BU and CY for the enhancement of DTH responses to SRBC were 10 mg/kg and 40 mg/kg respectively. Treatment of rats with BU (10 mg/kg) on day 5 induced the regression of KMT-17 cells, while in contrast, the same drug delayed the spontaneous regression of FV-KMT-17 cells. Pretreatment with CY (40 mg/kg) on day 5 did not affect the growth of KMT-17 or FV-KMT-17 cells. After the same treatment schedule, BU inhibited humoral antibody formation against SRBC and against virus-associated antigen (VAA), NK cell activity, and ADCC effector cell activity. On the other hand, CY did not affect the activities of NK cells or ADCC effector cells, although it significantly augmented the DTH responses to SRBC and the production of antibody to VAA but had no effect on production of antibodies to SRBC. These results suggest that NK cells and ADCC may play an important role in the initial stage of the spontaneous regression of FV-KMT-17 cells.Supported in part by a Grant-in-Aid for Cancer Research from the Japanese Ministry of Education Abbreviations used: BU, busulfan; CY, cyclophosphamide; PFC assay, plaque forming cell assay; VAA, virus-associated antigen; NK cell, natural killer cell; ADCC, antibody dependent cellular cytotoxicity; MuLV, murine leukemia virus; DTH, delayed type hypersensitivity; SRBC, sheep red blood cells; C.I., cytotoxic index; CRBC, chicken red blood cells; IL-1, interleukin 1; IL-2, interleukin 2; IFN, interferon     

Promotion of Flowering by DNA Base Analogues and Changes in Acid Phosphatase and Peroxidase Isozyme Composition in Dark-Grown Arabidopsis thaliana

A DNA base analogue, 5-bromodeoxyuridine (BUdR), promoted floweringof Arabidopsis thaliana in short and long photoperiods and evenin total darkness. The promotive effect of BUdR was nullifiedby thymidine which had a weak inhibitory effect by itself. AnotherDNA base analogue, 5-fluorodeoxyuridine (FUdR), inhibited theflowering at a low concentration (10^–8 M), but markedlyenhanced the promotive effect of BUdR if they were present togetherin the culture medium. In the flower-promoting medium containing both BUdR and FUdR,the number of acid phosphatase isozymes decreased temporarily,followed by an increase to the control level with a prolongedculture period. The number of peroxidase isozymes was greaterin plants grown in the medium with BUdR or BUdR $ FUdR thanin those without them. (Received October 22, 1987; Accepted March 25, 1988)     

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area

To assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (31P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSAmax) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J.cm-2 CSAmax for 1 min and an increment of 1 J.cm-2 CSAmax every minute to the point of muscle exhaustion. A series of measurements of 31P-MRS were performed every minute. The CSAmax was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm2, P less than 0.05]. The absolute maximal exercise intensity (J.min-1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J.min-1.cm-2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5'-diphosphate to drive adenosine 5'-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J.min-1.cm-2).(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth experiment of Hantaan virus in A549 cells: an attempt to improve the immunofluorescent antibody technique for hemorrhagic fever with renal syndrome

An assay method for the infectivity of Hantaan virus, a causative agent of HFRS (hemorrhagic fever with renal syndrome), was developed by the use of IFA (immunofluorescent antibody technique). With the aid of this method, the growth characteristics of Hantaan virus, 76-118 strain, were followed in A549 cells. At a maximal MOI (multiplicity of infection) of 1.6 VAIU (viral antigen-inducing units) per cell, the conventionally available value, plateau level potencies of the viral antigen and virus infectivity were attained at eight and ten days postinfection, respectively, and most of the infective virus produced accumulated in the culture fluids of infected cells. When infections were defined with MOI values in terms of VAIU per cell, development of the viral antigen was highly consistent and followed a given pattern of kinetics. Based on these findings, a protocol for preparation of the viral antigen in IFA was presented, wherein spot culture and FBS treatment were emphasized as effective procedures to minimize non-specific staining.     

Evaluation of tri-combinant vaccine for feline herpesvirus, calicivirus and panleukopenia virus infections in Japanese native cats

Tri-combinant vaccine consisting of attenuated feline herpesvirus (FHV) and feline calicivirus (FCV) and inactivated feline panleukopenia virus (FPLV), were evaluated for safety and efficacy, using Japanese native cats and the viral strains isolated in Japan. Thirty-eight 9- to 12-week-old kittens were inoculated intramuscularly and subcutaneously with the vaccine. Consequently, no adverse reaction was found, and protective efficacy was confirmed by challenge tests with the virulent strains of each virus. Serum-neutralizing antibodies against FCV and FPLV were maintained for at least one year after vaccination, whereas antibody against FHV disappeared in two cases at 24 weeks after vaccination. Application of this vaccine seemed effective for control of feline viral disease in cats for experimental use.     

Fine structural and immunohistochemical studies of goat adenohypophysial cells

Summary The fine structure of each type of anterior pituitary cell in the male goat was studied through the application of a superimposition technique in which adjacent thick sections were used to identify individual cells beforehand by light-microscopic immunohistochemistry. A cone of the pars intermedia protrudes into the pars anterior, being surrounded by the narrow pituitary cleft; the immunohistochemical appearances of the cells forming the cone resemble those of the pars anterior. Several follicles appear in the pars anterior. Ultrastructurally GH cells resemble prolactin cells. The secretory granules of both types are spherical; the diameter of the former is about 340 nm, whereas that of the latter is about 440 nm. ACTH cells are polygonal in shape with secretory granules, about 180 nm in diameter, scattered throughout the cytoplasm. TSH cells, which are spherical in shape, contain the smallest secretory granules, 150 nm in diameter. The highly electron-dense LH cells contain numerous secretory granules about 210 nm in diameter. Their nuclei are irregular with incisures. Thus, the anterior pituitary cells of the goat are ultrastructurally characteristic and species-specific.     

Serum and tissue coenzyme Q9 in rats with thyroid dysfunctions

Serum and tissue CoQ9 levels were determined in hypothyroid, euthyroid and hyperthyroid rats. A significant negative correlation was demonstrated between serum FT4 or T3 and CoQ9 in rats with various states of thyroid functions. Liver CoQ9 was significantly increased in rats rendered mildly hyperthyroid. There was a significant positive correlation between serum FT4 or T3 and liver CoQ9. While liver CoQ9 did not significantly change in severely hyperthyroid animals, liver mitochondrial CoQ9 showed a significant positive correlation with serum T3. Kidney and heart CoQ9 levels did not significantly change in hyperthyroid rats, but those in hypothyroid rats showed a tendency to increase. It was suggested that the synthesis of CoQ9 was increased in the liver in hyperthyroidism.