Biomedical subjects
Publications and source records attributed to M Itoh.
The concentration of free N-acetylneuraminic acid in various rat organs was estimated by gas chromatography/mass spectrometry. Its concentration was in the range of 3.95 to 104.72 micrograms/g wet tissues, being particularly high in the endocrine glands. The ratio of free N-acetylneuraminic acid to total N-acetylneuraminic acid varied from 0.031 to 0.183, being especially high in the adrenal gland (0.181) and heart (0.183).
It is now well known that insulin-dependent diabetes is a chronic progressive autoimmune disease. The prolonged prediabetic phase of progressive beta-cell dysfunction is associated with immunological abnormalities. A prediabetic period is suggested by the appearance of islet cell antibodies, anti-insulin antibodies, and anti-insulin receptor antibodies. The existence of activated T lymphocytes and abnormal T cell subsets are also other markers. There is still no concensus about the use of the immunosuppression superimposed upon conventional insulin therapy in early diagnosed IDDM and the follow-up of the relatives of IDDM patients who share the genetic predisposition and serological markers for the risk of future onset of IDDM. Treatment in the prodromal period cannot be justified because a link between the disease and early markers such as ICA has not been established with certainty (Diabetes Research Program NIH, 1983). Many immunopharmacological manipulations were reported to be effective in animal models. However, most of them are not readily applied to human subjects. Moreover, IDDM patients are now believed to be heterogeneous, with a complex genetic background. HLA-DR, and more recently DQ, are closely related to the genetic predisposition to IDDM but those genes are not themselves diabetogenic. The contribution of autoimmunity does not appear to be uniform, and in some cases, the contribution of virus is considered more important. There is a lack of a marker for the future onset of IDDM. ICA and ICSA were found after mumps infection, but the existence of those autoantibodies and even the co-existence of HLA-DR3 do not always indicate the future trend to insulin dependency. More precise markers will be disclosed through the biochemical analysis of the target antigens on pancreatic beta-cell for islet antibodies and effector T cells. Much safer and more effective immunopharmacological treatment will be developed through animal experimentation using rat and mouse models. The recent development and interest in this field will further facilitate the attainment of the goal for the complete prevention of IDDM.
Feasibility of fluorine-18 labeled L-dopa for melanoma imaging was investigated. In B16 melanoma-bearing mice given 2-[18F]fluoro-L-dopa, the radioactivity in the B16 decreased for the first 60 min and then remained constant, while all other tissues investigated decreased with time. High tumor uptake ratios for all other tissues except for the pancreas were obtained at 120 min. 6-[18F]Fluoro-L-dopa showed a similar tissue distribution. However, the B16 uptake was about half that value for the 2-fluoro analogue. A higher incorporation rate of 2-[18F]fluoro-L-dopa into the acid-precipitable fraction of the melanoma also showed that the 2-[18F]fluoro-L-dopa was a preferable melanin precursor. Among the four kinds of non-melanoma tumors in mice or rats three tumors showed an uptake of 2-[18F]fluoro-L-dopa similar to the B16 at 60 min. However, larger melanoma-to-tissue uptake ratios were observed when compared to non-melanoma tumors.
In order to appraise follicular development, human serum inhibin was measured daily by radioimmunoassay in 18 women undergoing ovarian hyperstimulation. Serum inhibin in the early follicular phase correlated with the number of follicles greater than or equal to 17 mm in diameter (r = 0.57, n = 18, P less than 0.05), follicles greater than or equal to 14 mm in diameter (r = 0.67, n = 18, P less than 0.01) on the day of human chorionic gonadotropin (hCG) administration and the number of oocytes retrieved (r = 0.67, n = 15, P less than 0.01). The number of oocytes retrieved showed a significant correlation with serum inhibin level on the day of hCG administration (r = 0.84, n = 15, P less than 0.001). These data suggest that: (1) In the early follicular phase, serum inhibin may be a valid index to predict ensuing follicular growth; (2) In the preovulatory phase, serum inhibin may be one of applicable indexes of follicular development during the hyperstimulation cycle.
In the previous study, we succeeded in isolating the cell-to-cell adherens junctions from rat liver (Tsukita, S., and S. Tsukita. 1989. J. Cell Biol. 108:31-41.). In this study, we have obtained mAbs specific to the 400-kD protein, which was identified as one of the major constituents of the undercoat of isolated adherens junctions. Immune blot analyses showed that this protein occurs in various types of tissues. Immunofluorescence microscopy and immune electron microscopy have revealed that this protein is distributed not only at the undercoat of adherens junctions but also along actin bundles associated with the junction in nonmuscle cells: stress fibers in cultured fibroblasts and circumferential bundles in epithelial cells. The partially purified protein molecule looks like a slender rod approximately 400 nm in length. By virtue of its molecular shape, we have named this protein 'tenuin' (from Latin 'tenuis', thin or slender).
A T-cell malignancy developed in a 64-year-old man with recurrent B-cell lymphoma after one and a half years of remission. Immunophenotypic and DNA analyses confirmed clonality and cell lineage of both lymphoid malignancies. Sequential development of B- and T-cell malignancies in this patient may be an example of biclonal lymphoma or treatment-related secondary lymphoma. However, another possibility would be the existence of a transformed lymphoid stem cell that underwent intraclonal conversion from B- to T-cell lines.
In vitro splicing of 11 different RNA transcripts carrying two introns was performed to determine whether the removal of an intron was dependent on its position or removal of the other intron. The original RNA transcript carried two identical units, each consisting of the first exon-first intron-a major part of the second exon of the human beta-globin gene. Five transcripts carrying a mutation in one of the two introns of the original RNA and one carrying mutations in both introns were prepared. One of the other RNA transcripts had a shorter middle exon than did the original transcript. The remaining three RNAs had at least one shortened form of the human beta-globin second intron. The results can be summarized as follows. 1) There was no obligatory order in the excision of the two identical or different introns, although the 5' proximal intron may be removed more rapidly in some cases. The efficiency of removal of the 5' proximal intron seems to be higher than or similar to that of the distal intron. 2) Excision of a mutated intron was inhibited, but no mutation significantly affected the excision of the other intact intron. 3) Except in an RNA transcript with two mutated introns, significant splicing between exon 1 and exon 3 (exon jumping) did not take place. 4) These results support the proposal that the two introns are basically independent of each other as to their removal.
The 3H concentration in Japanese human tissue samples is reported in this paper. Four brain, 10 liver, and nine lung samples from 11 cases were collected from Akita Prefecture in northern Japan from January to July 1986. The median of free-water 3H concentration was similar in these tissues and agreed well with the concentrations in the diet, including tap water. The median specific activity ratio of tissue-bound 3H to free-water 3H was 1.1 and was slightly lower than that in the diet. The specific activity ratio was also lower than that reported in the United States and significantly lower than in Italy.
To study fallout 3H ingestion in Japan, 16 separate food-group samples were collected from Akita City in northern Japan during early summer and late autumn in 1986. Furthermore, total diet samples which are duplicate composite food samples consumed by five or six persons for a period of 1 d were also obtained in Akita City. The 3H concentration in free water and that in a tissue-bound form were determined separately. Seasonal changes of 3H concentration in the food samples and the total diet samples were not found clearly. The average 3H concentration in the free water including tap water was 1.6 Bq L-1. The mean ratio of specific activity of tissue-bound 3H to that of 3H in free water was found to be 1.2. The average total 3H ingestion was estimated to be 4.0 Bq d-1, while the proportion of tissue-bound form 3H ingestion to total 3H ingestion was 11%. Cereal was the greatest contributing food group to ingestion of tissue-bound 3H. These findings were consistent with our previous results for food samples collected in 1985.
Cyclosporine treatment of BALB/c mice (at a dose of 20 mg/kg every other day for 3 weeks) caused a remarkable reduction in the PNA-, L3T4+Lyt-2- subset of thymocytes. A significant reduction of the L3T4+Lyt-2-subset was also observed in both the lymph node and spleen cells of CsA-treated mice, though the degree of the reduction was lower than that in thymocytes. Both lymph node and spleen cells from CsA-treated mice showed a significant increase in the percentage of Thy-1.2 negative, L3T4-Lyt-2- cells (perhaps B cells). Thymocytes from CsA-treated mice showed a reduction in the in vitro proliferative responses to Con A and PHA. On the other hand, there was a slight, but not significant, decrease in the responses of lymph node cells to Con A, PHA and LPS. Spleen cells from CsA-treated mice showed a significant reduction in the responses to Con A and PHA, though the degree of the reduction was lower than that of thymocytes. There was a significant decrease in the proliferative response of spleen cells to LPS. These results suggest that CsA affects both thymus and spleen cells in vivo, preferentially impairing the L3T4+Lyt-2- subset (helper T cells or their precursors) within the thymus. The lymph node cells seem to be relatively spared from the in vivo effect of CsA compared with cells in the thymus and spleen.
The cell wall of Clostridium difficile GAI 4131 was revealed by electron microscopy to have an outer layer composed of a nearly square array and contained the two major proteins with molecular weights of 38 kDa and 42 kDa. The properties and reassembly of the two major proteins into the regular array were investigated. When the isolated cell walls were treated with hydrophobic bond-disrupting agents or a chelating agent specific for Ca2+, the two major proteins were effectively removed and the regularly arranged outer layer disappeared. The amino acid composition of the two major proteins differed from each other. The two major proteins also gave different peptide maps from each other upon proteolysis with Staphylococcus aureus V8 protease. The major proteins solubilized from the isolated cell walls with 8 M urea or 4 M guanidine hydrochloride could be reassembled into open-ended cylinders possessing the native regular pattern by dialysis against neutral buffer containing 5 mM CaCl2. The reassembled cylinders purified by centrifugation on a Percoll density gradient were composed of almost equal amounts of the 38 kDa and 42 kDa proteins and freed from the other proteins. These results suggest that the regular array in the outer cell wall layer is constructed from the two major cell wall proteins and requires Ca2+ for its assembly.
Tumor detection with 11C-1-aminocyclopentane carboxylic acid (11C-ACPC) showed that this amino acid has a high affinity for malignant tumors. We studied the kinetics of intravenously injected 11C-ACPC in the rabbit VX-2 tumor using positron emission tomography. Three female rabbits bearing VX-2 tumor in the thighs were used. High uptake of 11C-ACPC was seen in the tumor and liver. 11C-ACPC in plasma decreased rapidly after injection and its activity in the tumor increased with time. The kinetic evaluation of ACPC uptake into the tumor was performed using the unidirectional transport model. The average values of the transfer constant of 11C-ACPC for VX-2 tumor were 0.030 +/- 0.002 ml/min/g. This preliminary result may form the basis for a quantitative analysis of the in vivo distribution of 11C-labeled ACPC in tumors.
Antigenicity of eggs (oncospheres), cysticercoids and adults (with immature segments only) of the bile duct tapeworm Hymenolepsis microstoma was analysed using immunoblotting techniques and indirect immunofluorescent antibody (IFA) techniques with immune sera of BALB/c mice (i) infected with different doses of cysticercoids, (ii) during patent or prepatent infection with the lumen phase of the parasite or (iii) sensitized with live or dead eggs. Antibody responses detected by IFA test and immunoblotting showed that antigenicity of eggs (oncospheres) differed from that of cysticercoids and adults. Single worm infections were sufficient to stimulate antibody responses. Mice which had patent infection showed strong antibody responses to all three (egg (oncosphere), cysticercoid, adult) antigens, while mice given two prepatent infections showed some antibody responses to cysticercoid and adult antigens only. Although the normal intermediate hosts of this parasite are arthropods, antibodies to some major egg (oncosphere) antigens were produced in mice given eggs of this parasite orally, either through inoculation of eggs or ingestion of faeces contaminated with eggs. Antibodies were not produced in mice dosed with non-viable eggs. The results are consistent with the hypothesis that cestode parasites express phase- (or stage-) specific antigens.
We developed an ELISA for measuring antisperm antibodies in the mouse by using serum samples obtained from mice immunized with murine testicular antigens in complete Freund's adjuvant (CFA) as well as from mice rendered vasectomized. Sperm antigens used were syngeneic epididymal spermatozoa and two types of soluble, murine testicular antigens prepared in our laboratory. This study deals with a) the sequential changes of antisperm antibody levels following immunization; b) determination of immunoglobulin classes of these antibodies; c) a correlation between the absorbance values and the endpoint titers of antisperm antibodies; and d) comparison of endpoint titers of antisperm antibodies detected by ELISA with those by immunoperoxidase staining method in immune and nonimmune sera. It is suggested that serum dilution as high as 1/800 or more is required for detecting antibody titers of immune sera, because nonimmune mouse sera reveal a definite, although low, level of absorbance value at a serum dilution of 1/400 or less.
The reaction of a new antitumor platinum complex, (R)-(-)-2-aminomethylpyrrolidine(1,1-cyclobutanedicarboxylato++ +)platinum(II) (1) with guanosine at room temperature in an aqueous solution was followed by proton nuclear magnetic resonance (1H-NMR) spectroscopy and high performance liquid chromatography (HPLC) at intervals. Both techniques showed that a new compound was formed by displacement of the 1,1-cyclobutanedicarboxylate moiety of 1 with two guanosines, and its 1H-NMR spectrum and HPLC chromatogram were proved to be identical with those of [(R)-(-)-2-aminomethylpyrrolidine]bis(N7-guanosine)platinum(II) (2), which was obtained upon successive treatment of (R)-(-)-2-aminomethylpyrrolidinedichloroplatinum(II) (3) with AgNO3 and 2 mol eq of guanosine in water. The binding sites of the platinum to the two guanosine moieties in 2 were confirmed by the pH dependence of the two G-H8 signals.
Glucose oxidase-labeled 11-deoxycortisol was tested for immunoreactivity in an enzyme immunoassay system using a monoclonal antibody. The antigen was labeled by the N-succinimidyl ester method. It was found that the binding affinity of the label to the anti-steroid antibody markedly decreased during storage; the half-life time was ca. 4.5 d.
Deflection area vectors of QRS (Aqrs) and T (At) and ventricular gradient (G) calculated from vectorcardiographic leads were compared in single vessel coronary artery diseases divided into subgroups of normokinetic, hypokinetic and akinetic by left ventriculography. In the LAD group, Aqrs shifted posteriorly, At were smaller and shifted to the right and G were smaller and shifted posteriorly or to the right. In the RCA group, Aqrs were smaller and shifted upwards, At shifted upwards and G were smaller and shifted upwards. In the LCx group, Aqrs shifted upwards, At shifted anteriorly and upwards and G were smaller and shifted upwards. Decreased magnitude and directional change of G reflect the severity and location of myocardial damage.
Rat epidermal growth factor was purified from rat submandibular glands to obtain specific antiserum for the establishment of an immunoassay system. Purified rat epidermal growth factor showed a single peak on reverse phase HPLC and a single band on sodium dodecyl sulphate polyacrylamide gel electrophoresis at mol wt 5100 in the presence of 2-mercaptoethanol and at mol wt 41,000 in the absence of 2-mercaptoethanol. Antibody against rat epidermal growth factor showed cross-reactivities with mouse and human epidermal growth factors on soft agar-double immunodiffusion test. The established sandwich enzyme immunoassay for rat epidermal growth factor had a high sensitivity (500 fg/tube), which made it possible to measure minute amounts of endogenous rat epidermal growth factor without pretreatment. Physiological concentrations of rat epidermal growth factor in rat biological fluids and tissues were determined. Species differences in physiological distributions of epidermal growth factor are discussed.