The effect of corticosteroids upon the number and organ distribution of "background" immunoglobulin-secreting cells in mice

The influence of the synthetic corticosteroid dexamethasone sodium phosphate (DEXA) upon the immunoglobulin (Ig)-secreting cells was studied in not intentionally immunized BALB/c mice. This was done for IgM-, IgG-, and IgA-secreting cells in spleen, mesenteric lymph nodes (MLN), and bone marrow (BM). A single injection of DEXA (16 to 144 mg/kg body wt) markedly reduced the number of Ig-secreting cells in spleen and MLN within 1 day, but hardly affected their number in the BM. The decrease was immediately followed by a recovery and, at the highest doses and especially in MLN, by an overshoot. Two weeks after the initial decrease a second decrease was found. When mice were subjected to daily treatment with DEXA during 1 week, initially a recovery pattern was found in spleen and MLN similar to that found after a single injection of a high dose. In this case, however, the effects were less dose dependent, and the overshoot reaction was followed by a period of subnormal numbers of Ig-secreting cells which lasted at least 1 week. This late effect of DEXA not only occurred in spleen and MLN, but also in the BM. The most prominent effect of daily treatment with DEXA was the long-lasting decrease of the number of IgG-secreting cells starting 1 week after withdrawal of treatment. This decrease was associated with a severely decreased serum IgG level.     

Regulation of natural killer cell activity by anti-I-region monoclonal antibodies

The effects of a monoclonal antibody directed against immune response gene products on mouse NK activity were examined. In vivo administration of an anti-I-A^k antibody to C3H/He (H-2^k) mice modulated their peritoneal cell (PC) and spleen cell (SC) natural killer (NK) activity against YAC-1 lymphoma target cells in vitro. No such effect was observed when BALB/c (H-2^d) mice were treated with this antibody. Administration of anti-I-A^k antibody to mice before and after infection with Toxoplasma or treatment with poly(I:C) leads to suppression of NK activity in comparison to NK activity of mice infected with Toxoplasma or injected with poly(I:C) alone. A similar treatment regimen with M5/114 antibody which reacts with I-A^b, I-A^d, I-E^d, and I-E^k molecules resulted in decreased NK activity in B10.D2 (H-2^d) but not in B10.BR (H-2^k) mice. Serum and cell culture supernatant interferon (IFN) concentrations were not altered as a result of anti-I-A^k treatment. Removal of adherent cells did not restore NK activity of anti-I-A^k-treated Toxoplasma-infected mice to levels obtained with mice infected with Toxoplasma. In contrast, depletion of Ly 2.1⁺ cells from nylon-wool nonadherent SC of mice treated with anti-I-A^k antibody, before and after infection with Toxoplasma, resulted in restoration of NK activity to the same level as that observed in Toxoptasma-infected mice.     

Preparation and characterization of a stable half met derivative of type 2 depleted Rhus laccase: Exogenous ligand binding to the type 3 site

We report the preparation and characterization of a stable half met (Cu(II)Cu(I)) type 2 copper depleted derivative of $\text{Rhus}$ laccase. Anion binding studies to this mixed valent type 3 protein form indicate no tight binding of anions nor group 1 - group 2 ligand behavior. This suggests that, in contrast to the well-characterized hemocyanins and tyrosinase coupled binuclear sites, exogenous ligands do $\text{not}$ appear to bridge the type 3 binuclear copper ions in laccase.     

Reactions between diglycolaldehyde dithioacetals and some nucleophiles

The homogeneous, neutral polysaccharide isolated from the crude polysaccharide of the fruit pulp from bael (Aegle marmelos) contains arabinose, galactose, and glucose in the molar ratios of 2:3:14. The linkages among the different monosaccharide residues were established through methylation analysis and Smith-degradation studies of the polysaccharide. The anomeric configurations of the different glycosyl groups were determined by study of the chromium trioxide oxidation of the acetylated polysaccharide. Results of these experiments have been discussed in order to assess the structure of the neutral polysaccharide.     

Preparation of 1-thioglycosides having ω-aldehydo aglycons useful for attachment to proteins by reductive amination

A series of 1-thioglycosides containing an ω-aldehydo group (as the dimethyl acetal) on the aglycon were prepared by reaction of O-acetyl-1-thioaldoses with N-(chloroacetyl)aminoacetaldehyde dimethyl acetal, a compound readily prepared by the action of chloroacetyl chloride or chloroacetic anhydride on 2-aminoacetaldehyde dimethyl acetal. O-Deacetylation of the 1-thioglycosides, followed by deacetalation, yielded the desired products. An analogous 1-thioglycoside having a longer aglycon was prepared by reaction of 1-thio-D-galactose with (6-aminohexanoyl)-aminoacetaldehyde dimethyl acetal, obtained by condensing 6-bromohexanoic acid and aminoacetaldehyde with 3-(3-dimethylaminopropyl)-1-ethylcarbodiimide. These glycosides were found to be useful for modification of proteins to yield neoglyco-proteins.     

Mutagenicity and irreversible binding of the hepatocarcinogen, 2,4-diaminotoluene.

Mutagenicity of 2,4-diaminotoluene (DAT) in the Salmonella mutagenicity assay was increased with liver fractions from phenobarbital (PB) or beta-naphthoflavone (BNF) treated rats. Substitutions of the hydrogens in the methyl group of 2,4-DAT with deuterium resulted in a decrease in mutagenicity. Incubation of rat liver microsomes with tritiated 2,4-DAT in the presence of NADPH led to the formation of irreversibly bound products to microsomal protein. The rates of binding were not increased using microsomes from PB or BNF-treated rats and was not altered by deuterium substitution in the methyl group. Addition of superoxide dismutase, glutathione (GSH) or rat liver supernatant reduced 2,4-DAT irreversible binding, whereas 2,4-DAT mutagenicity was unaffected by superoxide dismutase addition. Injection of tritiated 2,4-DAT 100 mg/kg to rats lead to its irreversible binding to liver protein and ribosomal RNA and to kidney protein in vivo, again protein binding was not increased after prior treatment with PB or BNF. No irreversible interaction of tritiated 2,4-DAT with DNA either in vitro or in vivo could be demonstrated.     

Gas chromatographic measurement of urinary 5-fluoro-2'-deoxyuridine levels after barium salt precipitation and sephadex LH-20 cleanup

A fluorescent photoaffinity label—8-azido-1-N⁶-etheno-adenosine 5′-triphosphate (8-N₃ε ATP)—for ATP-binding proteins has been synthesized. The effectiveness of the label is demonstrated with F₁ATPase from Micrococcus luteus. 8-N₃ε ATP is a substrate for the enzyme in the presence of bivalent cations. Ultraviolet irradiation of F₁ATPase in the presence of the label and Mg²⁺ ions inhibits the enzyme irreversibly. The fluorescent label is bound preferentially to the β subunit of the enzyme. Labeling and inactivation are decreased by protection with ATP or ADP.     

Failure of a variety of antiestrogens to mimic estrogen action in the induction of sexual receptivity in a female lizard

The purpose of the present study was to determine whether nonsteroidal antiestrogens could act as estrogens by inducing or facilitating estrogen-induced sexual receptivity in a female lizard (Anolis carolinensis). Experiments were conducted to (1) test the ability of enclomiphene (ENC) and zuclomiphene (ZUC) to induce sexual receptivity in estrogen-untreated ovariectomized females; (2) to determine the effect of ENC and ZUC pretreatment on E₂B induction of sexual receptivity; and (3) to examine the ability of a variety of antiestrogens to act as estrogens by inducing sexual receptivity in females pretreated with a behaviorally ineffective estrogen treatment regimen.     

Anti-clotting activity of endothelial cell cultures and heparan sulfate proteoglycans

A photoaffinity probe for the vitamin D-dependent chick intestinal calcium binding protein (CaBP) has been prepared by conjugation of methyl-4-azidobenzoimidate (MABI) to lactoperoxidase-¹²⁵I-iodinated CaBP to yield ¹²⁵I-CaBP-MABI: [3 moles MABI per mole CaBP]. After incubation $\text{in}\text{vitro}$ of ¹²⁵I-CaBP-MABI (28,000 daltons) in model systems with bovine intestinal alkaline phosphatase (AP) (67,000 daltons), a UV light-dependent crosslinking occurred to yield a conjugate with a molecular weight of 95,000 (by SDS-gel electrophoresis); no crosslinking occurred with $\text{E.}\text{coli}$ alkaline phosphatase. The formation of the ¹²⁵I-CaBP-MABI-AP was found to occur only in the presence of calcium.     

Development of cerebellar astroglia: Transitions in form and cytoskeletal content

The forms, disposition, and cytoskeletal contents of astroglia in immature mouse cerebellum were studied by immunocytochemical staining with antisera against two intermediate filament proteins, vimentin (Vim) (58,000 daltons) and glial filament protein (GF) (51,000 daltons). From embryonic (E) Day 15 to postnatal (P) Day 2, Vim is expressed in cells throughout the cerebellar anlage, including radial glia and Bergmann fibers, cells with amorphous shapes and 2–3 processes, and thick longitudinal elements oriented parallel to axons within axon tracts. GF is not expressed during the first few postnatal days, but by P7, there is a dramatic increase in GF-positive astrocyte-like cells in the putative white matter that are more densely stained and more crowded than at any other age. Between P7 and P14 all astrocytes throughout the cerebellum express both Vim and GF. From P21 on, Vim expression is progressively rarer in all astrocytes except for Bergmann fibers, and GF-positive astrocytes become less numerous. These findings raise two issues: (a) the lineage and relationships of cells expressing Vim and GF; (b) Since GF-positive cells appear as axon ingrowth ceases, axons must grow in a terrain comprised of glial cells that have a different cytoskeletal composition (vimentin), reflecting a less differentiated state, than mature astrocytes or than the GF-rich astrocytes that proliferate after injury in adult CNS.     

Structural glycoprotein from the media of pig aorta. Aggregation of the S-carboxamidomethyl subunits.

Media of pig aorta was extracted with 1 M NaCl and 2 M MgCl2 to remove most of the soluble collagen, proteoglycans and glycoproteins. The glycoproteins remaining in the residue were extracted with 6 M urea-0.1 M mercaptoethanol. The urea soluble proteins were precipitated by dialysis, redissolved in 4 M guanidine-0.05 M DTT and were S-carboxamidomethylated (CM-guanidine extract). This extract was further fractionated by a variety of methods in order to separate a glycoprotein from collagen and proteoglycans. Caesium chloride density-gradient ultracentrifugation of the CM-guanidine extract separated a minor proteoglycan peak from a major glycoprotein fraction still containing some hydroxyproline. This major glycoprotein fraction was excluded as a single peak from Sephadex G 100 and G 200 in 4 M guanidinium chloride or in 6 M urea-0.2 per cent SDS. Sodium dodecylsulphate gel electrophoresis separated this high molecular weight Sephadex fraction into a major low molecular weight (approximately 35000 daltons) component and a minor high molecular weight component. This glycoprotein fraction could also be separated from a collagenous fraction and from proteoglycans by ion exchange chromatography on DEAE cellulose or by gelfiltration on Sepharose 4 B in 6 M urea-0.02 M EDTA-0.2 per cent SDS at pH 7.0. The isolated glycoprotein fraction is rich in dicarboxylic amino acids, contains galactose, mannose, (glucose), N-acetylglucosamine and sialic acid. The S-carboxamidomethyl glycoprotein preparation interacts with acid soluble calf skin collagen on isoelectric focusing in sucrose gradient in urea. This interaction is in favour of the biological role claimed for structural glycoproteins during fibrogenesis and differentiation.     

X-ray crystal and molecular structures of the Ni(II) and Co(II) complexes of 2'-deoxyguanosine-5'-monophosphate.

The structures of [Ni(5′-dGMP)(H₂O)₅] and [Co(5′-dGMP)(H₂O)₅] have been solved by single-crystal x-ray diffraction techniques. Their common geometry consists of a metal ion octahedrally coordinated to the N₇ atom of guanine and five water ligands. The phosphate group of the nucleotide is hydrogenbonded to two of the coordinated water molecules.