Biomedical subjects
Publications and source records attributed to N Koizumi.
2-Azachlormadinone acetate (5a, 17-acetoxy-6-chloro-2-azapregna-4,6-diene- 3,20-dione), 2-oxachlormadinone acetate (6, 17-acetoxy-6-chloro-2-oxapregna-4,6-diene-3,20-dione) and the derivatives were prepared as potential antiandrogenic agents. Biological evaluation showed that 5a and 6 had a potent antiandrogenic activity when tested in the castrated male rat.
Changes in the levels of plasma cortisol, progesterone and total testosterone were examined in developing hairless and haired dogs. Cortisol levels in the hairless dogs seemed to be higher than those in haired dogs within the age of 4-5 weeks. No apparent changes were seen in the level of plasma progesterone between the groups of hairless females and haired females. Total testosterone levels in hairless males showed to be significantly lower than those in haired males at the age of 13-21 weeks.
Lymphocyte blastogenesis in hairless descendants of Mexican hairless dogs was examined using the following mitogens: phytohemagglutinin (PHA-M), Concanavalin A (Con A), lipopolysaccharide (LPS) and pokeweed mitogen (PWM). Blastogenetic responses to these mitogens were measured by glucose consumption test (GCT) and compared with those of haired beagle dogs. The response to PHA-M was significantly less in the hairless dogs than in the beagles. No significant differences in the responses to Con A, PWM and LPS were recognized. These results indicated T-cell dysfunction in the hairless dogs, coinciding with our previous work showing reduction of the delayed-type hypersensitivity reaction and early degeneration of the thymus.
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The skin and lymphoid organs of Mexican hairless dogs and their hairless offspring were examined histologically. The hairless dogs lacked most hairs except for sparse hairs on the head, tail and feet. The skin of newborn pups consisted of a thick epidermis with epidermal ingrowths forming the rudiments of hair follicles. In older dogs more than 2 months of age, however, the epidermis was thin and the ingrowths were few. Neither hair follicles nor skin glands were present. The hairy skin of the head and tail had hair follicles with sebaceous glands. Regarding the lymphoid organs, the newborn pups possessed a thymus like haired pups. But in the older dogs more than 2 months of age, the thymus was atrophied and the lymphocyte population was too sparse to demarcate the cortex and the medulla. Lymphocyte accumulation in older dogs was also poor in the spleen and mesenteric lymph nodes. The present findings indicate that the hairlessness of the Mexican hairless dogs and their descendants is accompanied by early atrophy of the thymus after birth, and is followed by poor accumulation of lymphocytes in the thymus-dependent area of the spleen and the mesenteric lymph nodes. The defect of the thymus in the hairless dog seems to be different from that in athymic nude mice and rats. Further studies are needed to elucidate the immunological response and function in hairless dogs.
Rice alpha-amylases are encoded by a multigene family that has previously been classified into 5 hybridization groups. DNA sequence and Southern blot analysis identified three genes (RAmy1A, RAmy1B and RAmy1C) in Group 1 with DNA sequence identity of at least 90%. Hybridization Group 2 is represented by only one gene, RAmy3D, which is identical to a previously characterized cDNA, pOS137. RAmy3D is physically linked to the sole representative of Group 5, RAmy3E. The identity between these two genes is 81.4% in the coding region but less than 50% in the 5' and 3' flanking regions. Northern blot analysis and RNA-PCR were used to detect the expression of alpha-amylase genes in various tissues. Alpha-amylase mRNA was abundant in germinating seeds and callus. Some genes were also expressed at much lower levels in roots, young leaves and immature seeds. RAmy1A and RAmy3E were expressed in all tissues while RAmy3D was expressed in all tissues except the immature seeds. RAmy1B was weakly expressed only in callus. RAmy1A transcript was most abundant in the germinating seeds, while RAmy3D and RAmy3E transcripts were most abundant in callus and immature seeds, respectively.
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The activity of thyroid peroxidase (TPO) in porcine follicles cultured for 96 h in suspension with five hormones (5H) still attained over 50% of that in the freshly isolated follicles. On the other hand, the activity in those cultured with 5H + TSH (6H) was several times higher than that cultured with 5H after 96 h, although an initial decrease of TPO activity during the first 24 h of culture was observed in both conditions. The ability of follicles to metabolize iodide (uptake and organification) when cultured with 6H for 96 h was also several times higher than that of those cultured with 5H. The half-maximal dose of TSH for stimulation of TPO activity and iodide metabolism was 0.03-0.04 mU/ml and the effect was mediated by cAMP. These results indicate that in porcine thyroid follicles in primary suspension culture, TPO activity as well as the ability of iodide metabolism is induced by chronic TSH stimulation. In addition, epidermal growth factor (EGF, 10(-9)M) and phorbol 12-myristate 13-acetate (PMA, 10(-8) M) completely inhibited TSH stimulation on both activities and also basal (5H) activity of iodide metabolism.
The concentrations of Cd, Zn, Cu, and metallothionein (MT) in the liver, renal cortex, and renal medulla were determined in 24 male and 15 female younger thoroughbreds (age 27 to 97 months) and two old male horses (age 154 months and 190 months). High correlations were found between Zn and MT in the liver (partial correlation coefficient 0.836), between Cd and MT in the renal cortex (partial correlation coefficient 0.786), and between Cd and Zn in the renal cortex (partial correlation coefficient 0.675), while the correlation between Cd and MT in the liver was low (partial correlation coefficient 0.124). In the renal medulla, high correlations were found between Cd and Zn (partial correlation coefficient -0.631), between Zn and Cu (partial correlation coefficient 0.881), and between Cd and Cu (partial correlation coefficient 0.785). Therefore, in the liver, the MT concentration is the most highly correlated with the Zn concentration and is not correlated with the CD concentration unless artificially exposed to Cd. In the renal cortex, the MT and Cd concentrations are very highly correlated with each other. The Zn concentration is about 20 micrograms/g when the Cd concentration in the renal cortex is the lowest.
cDNA clones for the (S)-tetrahydroberberine (H4Ber) oxidase of cultured berberine-producing Coptis japonica cells were isolated by screening a C. japonica cDNA library with synthetic nucleotides that can encode the NH2-terminal sequence of this enzyme. Analyses of the nucleotide sequences of the cloned cDNA inserts revealed a 759-base-pair open reading frame that encoded a 253-amino acid polypeptide with a Mr of 27,089 and NH2-terminal and internal sequences identical with those of the (S)-H4Ber oxidase, as determined by microsequencing methods. Escherichia coli were transformed with an expression vector carrying (S)-H4Ber oxidase cDNA. The transformed bacteria were induced to overproduce a 28-kDa protein that reacted with Coptis (S)-H4Ber oxidase-specific antibody. A comparison of the derived amino acid sequence of (S)-H4Ber oxidase with sequences in the protein data base of the Protein Research Foundation showed a marked similarity between (S)-H4Ber oxidase and the NH2-terminal portion of mouse P1-450, which is encoded by a single exon of the mouse P1-450 gene. The availability of cloned cDNA for (S)-H4Ber oxidase allows use of the methods of molecular biology to study the regulation of (S)-H4Ber oxidase gene expression in cultured C. japonica cells in relation to berberine biosynthesis.
A set of 16 serotype specific monoclonal antibodies (MoAbs) against Pseudomonas aeruginosa classified by Homma were obtained by the mouse hybridoma technique. This set of MoAbs was useful for classification of their serotypes especially O-antigen groups G and M. MoAb obtained from serotype 15 of Homma's classification reacted with serotype 17 of the same classification. We also obtained two MoAbs which reacted with 7 Homma's serotypes of 6 different O-antigen groups and one MoAb which recognized all 4 Homma's serotypes of O-antigen group B. These MoAbs were also useful in mice for the preventive effect against the infections of P. aeruginosa.
A high degree of external nasal obstruction will by itself decrease nasal airway resistance. However, a controlled series of experiments in normal volunteers has shown that this lessened resistance is still not able to balance the level of the external obstruction present. The implications of this finding are discussed.
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Sheep liver, kidney, bone marrow, and erythrocytes gave their own specific patterns of neutral and acidic glycosphingolipids. A major neutral glycosphingolipid was found to be lactosylceramide in the liver and bone marrow, glucosylceramide in the kidney, and Forssman glycolipid in the erythrocytes, respectively. The Forssman glycolipid was not found in the liver, kidney, bone marrow, leukocytes, platelets and plasma even by a sensitive thin layer chromatography immunostaining, but two unknown glycosphingolipids, reactive to Forssman antibody, were slightly recognized in addition to Forssman glycolipid in the erythrocytes. Sulfolipids were found certainly in the kidney, but not found in the other tissues and cells. GM3 as a major ganglioside and other minor gangliosides whose sialic acids consisted of both N-acetylneuraminic acid and N-glycolylneuraminic acid were found in liver, kidney, leukocytes, platelets, and plasma, whereas the sheep erythrocytes were found to contain three major gangliosides of GM3, disialosyltetraglycosylceramide (probably disialosyllactoneotetraosylceramide) and disialosylhexaglycosylceramide (probably disialosyllacto-norhexaosylceramide) which had N-glycolylneuraminic acid and N-acetyl-neuraminic acid.
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