Mapping of Histamine H1 Receptors in the Human Brain Using [11C]Pyrilamine and Positron Emission Tomography

We have studied the characteristics of carbon-11 labeled pyrilamine as a radioligand for investigating histamine H1 receptors in human brain with positron emission tomography (PET). [11C]Pyrilamine is distributed evenly in proportion to cerebral blood flow at initial PET images. Later (after 45-60 min), 11C radioactivity was observed at high concentrations in the frontal and temporal cortex, hippocampus, and thalamus, and at low concentrations in the cerebellum and pons. The regional distribution of the carbon-11 labeled compound in the brain corresponded well with that of the histamine H1 receptors determined in vitro in autopsied materials. In six controls, the frontal and temporal cortices/cerebellum ratio increased during the first 60 min to reach a value of 1.22 +/- 0.071. Intravenous administration of d-chlorpheniramine (5 mg) completely abolished the specific binding in vivo in the frontal cortex and temporal cortex (cortex/cerebellum ratio, 0.955 +/- 0.015). The availability of this method for measuring histamine H1 receptors in vivo in humans will facilitate studies on neurological and psychiatric disorders in which histamine H1 receptors are thought to be abnormal.     

Phenotypic progression of a rat lymphoid cell line immortalized by human T-lymphotropic virus type I to induce lymphoma/leukemia-like disease in rats.

Rat lymphoid cells, TARS-1, immortalized by coculture with adult T-cell leukemia cells, were intraperitoneally injected into 65 newborn, inbred WKAH/Hkm rats. In most of the rats, tumor nodules were discernible 7 to 15 days after transplantation but were completely rejected within 5 to 6 weeks. Two rats with no tumor nodules exhibited gait disturbances and paralysis of the hind legs 3 to 4 weeks after transplantation. Histological and hematological examinations revealed that a lymphoma/leukemia-like disease had developed in one of the two rats, and the T-lymphoid cell line WLeuk-1 was established from peripheral blood mononuclear cells from this rat. When the WLeuk-1 cells were transplanted into newborn WKAH/Hkm rats, the animals died of a lymphoma/leukemia-like disease within several weeks after transplantation, in contrast to their rejection of the TARS-1 cells. Southern blot and karyotype analyses revealed that WLeuk-1 cells had retained the marker chromosomes and human T-lymphotropic virus type I (HTLV-I) integration patterns of the parent cell line, TARS-1. The additional specific chromosome abnormalities 3p+,t (12;13), and Xq+ were found in the WLeuk-1 cells. Moreover, the expression of HTLV-I structural proteins was slightly depressed in WLeuk-1 cells, while that of the transacting factors p40tax and p21x, but not that of p27rex, was enhanced about fivefold compared with that in TARS-1. The transactivating function of p40tax was intact in WLeuk-1, as evidenced by enhanced interleukin-2 receptor alpha chain expression. These results suggest that aberrant expression of HTLV-I regulatory genes and alteration of cellular genes were associated with the phenotypic progression of the WLeuk-1 cell line.     

Recombinant transforming growth factor type beta 3: biological activities and receptor-binding properties in isolated bone cells.

We have recently cloned the cDNA for transforming growth factor type beta 3 (TGF-beta 3), a new member of the TGF-beta gene family. We examined the biological effects of recombinant TGF-beta 3 protein in osteoblast-enriched bone cell cultures. In this report we demonstrate that TGF-beta 3 is a potent regulator of functions associated with bone formation, i.e., mitogenesis, collagen synthesis, and alkaline phosphatase activity. In a direct comparison between TGF-beta 3 and TGF-beta 1, TGF-beta 3 appeared to be three- to fivefold more potent than TGF-beta 1. Our cross-linking experiments with iodinated TGF-beta showed that in osteoblast-enriched bone cell cultures, both TGF-beta 3 and TGF-beta 1 associated with the same three cell surface binding sites. Scatchard analysis of receptor competition studies indicated the presence of high-affinity binding sites for TGF-beta 3 in the picomolar range. TGF-beta 3 showed an approximately fourfold-higher apparent affinity than TGF-beta 1 in overall binding.     

Relationship between T cell receptors and antigen-binding factors. I. Specificity of functional T cell receptors on mouse T cell hybridomas that produce antigen-binding T cell factors

Upon antigenic stimulation with OVA-pulsed syngeneic macrophages, the mouse T cell hybridoma 231F1 produced glycosylation inhibiting factor (GIF) having affinity for OVA and IgE-suppressive factors, whereas another T cell hybridoma, 12H5, cells produced OVA-binding glycosylation enhancing factor (GEF) and IgE-potentiating factor. The OVA-binding GIF from the 231F1 cells is an Ag-specific Ts cell factor, whereas OVA-binding GEF from the 12H5 cells is an Ag-specific augmenting factor. Both hybridomas express CD3 complex and functional TCR-alpha beta. Cross-linking of TCR-alpha beta or CD3 molecules on the hybridomas by anti-TCR-alpha beta mAb or anti-CD3 mAb and protein A resulted in the formation of the same factors as those obtained by the stimulation of the cells with OVA-pulsed syngeneic macrophages. It was also found that both the 231F1 cells and 12H5 cells formed IgE-binding factors upon incubation with H-2d and H-2b APC, respectively, with a synthetic peptide corresponding to residues 307-317 in the OVA molecules (P307-317). Six other synthetic peptides, including those containing the major immunogenic epitope, i.e., P323-339, failed to stimulate the hybridomas in the presence of APC. Indeed, all of the 10 T cell hybridoma clones, which could produce either OVA-binding GIF or OVA-binding GEF, responded to P307-317 and APC for the formation of IgE-binding factors. In contrast, GIF/GEF derived from six other hybridoma clones, whose TCR recognized P323-339 in the context of a MHC product, failed to bind to OVA-coupled Sepharose. The results indicate the correlation between the fine specificity of TCR and the affinity of GIF/GEF to the nominal Ag. The amino acid sequence of P307-317 suggested that TCR on the cell sources of Ag-binding factors are specific for an external structure of the Ag molecules.     

Catalytic action of selenium in the reduction of methemoglobin by glutathione

Selenite, selenate and selenocystine catalyzed the reduction of methemoglobin (metHb) by glutathione (GSH), while selenomethionine did not. Maximal reduction of metHb was observed with 10^?5 M selenite and 2 mM GSH, at pH 7.4. Selenite also catalyzed the reduction of metHb with cysteine or 2-mercaptoethylamine in place of GSH. Heavy metals and arsenite completely prevented the effect of selenite. These findings suggest that certain seleno-compounds catalyze the reduction of metHb by thiol compounds.     

Stationarity and normality test for biomedical data.

Biomedical data, such as EEG, EMG and neural impulse sequences, are regarded as the stochastic phenomena of biological systems, and the statistical properties of such time series are often examined. Most of the statistical analysis processed in the frequency and the time domain are based on the assumption that the time series is weakly stationary and normally distributed. Therefore, as the basis of the statistical analysis of the biomedical data, it is necessary to know whether they satisfy the conditions of weak stationarity and normality. However, impulse response and evoked potential biomedical data, are not regarded as the stationary time series. Therefore, other analysis is required. In this paper, the authors present four programs, TEST1, TEST2, TEST3 and TEST4, to examine above conditions. Furthermore, in order to clarify the characteristic of each program, the time series were generated by the computer and examined by the test programs.     

Interaction between thymopoietin and facteur thymique serique in the rosette inhibition assay.

In the rosette inhibition assay, thymopoietin was active and its activity was enhanced in the presence of high concentrations of ubiquitin. Facteur thymique serique (FTS) was active in the same assay, but its activity was completely inhibited by high concentrations of ubiquitin. Mixtures of thymopoietin and FTS showed activity both in the presence or absence of ubiquitin depending on the concentration of thymopoietin or FTS in the mixtures. There seemed to be an important biologic interaction of thymopoietin and FTS when presented as a mixture, suggesting that thymopoietin and FTS might interact $\text{in}\text{vitro}$ and possibly $\text{in}\text{vivo}$.     

Possible regulation of thiamine diphosphatase activity in rat brain microsomes by lipids.

The effects of various treatments, which affect membrane structure, on microsomal thiamine diphosphatase and thiamine triphosphatase activities of rat brain, were examined. The treatment of micorosomes at alkaline pH caused a 2-fold activation of the thiamine diphosphatase, this being related to a change in membrane structure which was evidenced by a decrease of the turbidity of the microsomal suspension. Repeated freezing and thawing after hypo-osmotic treatment also increased the activity of microsomal thiamine diphosphatase. In addition, the thiamine diphosphatase activity was enhanced by treatment of the microsomes with phospholipase C or acetone. This lipid depletion resulted in a marked reduction in the apparent Km value of the thiamine diphosphatase with a corresponding loss in heat stability of the enzyme. We found further that brain thiamine diphosphatase was solubilized by Triton X-100. This decreased the phospholipid content in the preparation, but did not affect the apparent Km value and heat stability of the enzyme. In contrast with thiamine diphosphatase, thiamine triphosphatase was inactivated by treatment at alkaline pH or with acetone. However, treatment with phospholipase C did not affect the activity of thiamine triphosphatase.     

Effect of limited proteolysis of potato phosphorylase on activity and structure.

The course of the proteolysis of potato α-gluean phosphorylase (EC 2.4.1.D has been followed hy means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and by determination of residual activity. Trypsinolysis results in rapid hydrolysis in the middle part of the polypeptide chain (site a) without loss of enzyme activity, followed by much slower cleavage near the terminus (site b) which accompanies a significant decrease in activity. Substrate causes suppression of the inactivation and of the hydrolysis at site b, but not of the one at site a. The results of a kinetic study indicate that the site of substrate binding interacts directly with site b. Preferential hydrolysis in the middle part of the chain has been observed also in the case of chymotrypsinolysis. The results are discussed in connection with the structure of potato phosphorylase.     

Fibronectin-induced migration of melanophores in vitro in scales of medaka,Oryzias latipes

Summary The effects of fibronectin on melanophores were examined in two mutant strains of medaka, Oryzias latipes: mm (BmmR), which has condensed melanophores and normal dendritic melanophores; and cm (BcmR), which has condensed melanophores. When medaka scales were cultured in the presence of fibronectin, melanophores of the wild type and dendritic melanophores of the mm mutant changed their shape and migrated, whereas melanophore migration was rarely seen in the absence of fibronectin. Melanophores of the cm mutant and condensed melanophores of the mm mutant did not migrate even in the presence of fibronectin. When melanophores of the wild type and mm mutant were condensed by adrenalin, they did not migrate. On the other hand, when melanophores of the cm mutant were dispersed by theophylline, they were able to migrate. These results indicate that fibronectin induces the migration of melanophores and that dispersion of melanin granules may be requisite for such migration.