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Biomedical subjects

M Shima

Publications and source records attributed to M Shima.

At least 145 records · Page 8Linked to original sources
PubMed1991

Changes in polypeptide-specific factor VIII antigen levels during whole blood clotting.

The time-course of factor VIII (FVIII) proteolysis during whole blood coagulation was monitored using polypeptide-specific enzyme-linked immunosorbent assays (ELISAs) developed with monoclonal antibodies to FVIII. Such assays of whole blood from normal subjects revealed that, within 30 min after coagulation had started, levels of the amino-terminal region of FVIII light chain and in the middle region of FVIII heavy chain had decreased to baseline in parallel with factor VIII procoagulant activity, but that levels of the 70 kDa thrombin digest decreased more slowly, with 75 U/dl of FVIII antigen (FVIII:Ag) remaining even after 2 h. Similar analysis of the blood of a patient with congenital hypoprothrombinemia indicated a lag phase of 20 min before proteolysis started. No significant change was observed until 1 h after calcium chloride was added to prothrombin-depleted plasma. On the other hand, in the presence of tissue thromboplastin, levels of FVIII:Ag in all ELISAs decreased rapidly. These results indicate a requirement for thrombin generation in the proteolysis of FVIII during the process of whole blood clotting.

Blood Coagulation↗
PubMed1991

Clinical evaluation of recombinant human factor VIII (BAY w 6240) in the treatment of hemophilia A.

A pilot clinical trial was conducted in five patients with severe hemophilia A to evaluate the safety and efficacy of a recombinant human factor VIII preparation, BAY w 6240 (rFVIII). In a comparative pharmacokinetic study of rFVIII and a plasma-derived factor VIII preparation (pdFVIII), the mean t1/2 values for rFVIII at week 1 and week 13 were 16.8 and 14.4 h, while this value for pdFVIII at week -2 was 16.9 h. There were no statistical differences between these values. The mean in vivo recovery rates of rFVIII were comparable to those of pdFVIII. When rFVIII was administered prophylactically three times a week for 4 weeks, no bleeding episodes were observed. Seventy-four bleeding episodes were assessed during the 6-month treatment period. The efficacy rate of the hemostatic effect was confirmed to be 95.9%. No adverse reactions attributable to rFVIII were observed in a total of 178 infusions. Neither FVIII-inhibitors nor antibodies to foreign proteins were detected. Vital signs and laboratory findings showed no significant changes attributable to rFVIII. These results suggest that rFVIII is safe and efficacious as replacement therapy for hemophilia A.

Adult↗
PubMed1990

Changes in HBsAg carrier rate in Goto Islands, Nagasaki Prefecture, Japan.

Annual mass examinations in an area where hepatitis B virus (HBV) infection is very prevalent revealed that 12.1% of inhabitants born during 1946-50 were positive for hepatitis B surface antigen (HBsAg), compared with only 0.6% of those born during 1971-75. To find out why the HBV carrier rate has fallen, changes in the modes of HBV infection were examined. The HBsAg positivity rate among mothers who gave birth to HBV carrier children in 1965 and before was 26.8% and that for such mothers whose babies were born in 1966 and after was 66.7%, whereas the HBsAg positivity rate among children born to HBV carrier mothers in 1965 and before and in 1966 and after were 30.8% and 28.3%, respectively. None of the 503 inhabitants who had no HBV markers in 1976 had become carriers by 1981. These findings indicate that the decrease in the prevalence of HBV carriage is caused mainly by the reduction in occurrence of horizontal transmission of HBV in infancy.

Adolescent↗
PubMed1990

Temperature-dependence of desensitization induced by acetylcholine and histamine in guinea-pig ileal longitudinal muscle.

1. The effects of temperature on the time course of desensitization induced by acetylcholine and histamine, and on the recovery from desensitization were studied in the longitudinal muscle of the guinea-pig ileum. 2. Self- and cross-desensitization produced by acetylcholine (10(-5) M) occurred rapidly in the first 10 min of exposure to the agonist, with the same time course and the same degree of desensitization over the temperature range of 11 degrees C to 31 degrees C. 3. Self-desensitization produced by histamine (10(-5) M) also occurred rapidly in the first 10 min of exposure to the agonist, and showed great temperature-dependence, especially at 11 degrees C and 21 degrees C, but scarcely occurred at 6 degrees C. 4. Cross-desensitization produced by histamine developed gradually with time and showed a moderate temperature-dependence between 11 degrees C and 31 degrees C, but scarcely occurred at 6 degrees C. 5. The recovery processes from desensitization showed marked temperature-dependence. Recovery was halted completely at 11 degrees C. 6. These studies suggest that acetylcholine-induced desensitization may be attributed to a single non-specific mechanism. Histamine-induced desensitization may be due to at least two mechanisms: it occurs in both a specific and non-specific manner. Each of these desensitizations can be characterized by its unique temperature-dependence.

Acetylcholine↗
PubMed1990

23(S),25(R)-1,25-dihydroxyvitamin D3-26,23-lactone stimulates murine bone formation in vivo.

23(S),25(R)-1,25-Dihydroxyvitamin D3-26,23-lactone (1,25-lactone) has been shown to have unique actions different from those of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. In contrast to 1,25-(OH)2D3, 1,25-lactone causes a significant reduction in the serum Ca2+ level, stimulates collagen production in an osteoblastic cell line, and inhibits bone resorption induced by 1,25-(OH)2D3. A possible effect of 1,25-lactone on bone formation was examined in experiments on ectopic bone formation using a bone-inducing factor derived from Dunn osteosarcomas. 1,25-Lactone, a metabolite of 1,25-(OH)2D3, increased [3H]proline uptake at the stage of chondrogenesis and 85Sr uptake during bone formation. Significantly enlarged bone was also induced by this compound 3 weeks after implantation. These results suggest that the 1,25-lactone may be able to stimulate bone formation under in vivo conditions.

Animals↗
PubMed1990

Immunoscintigraphy of human tumors transplanted in nude mice with radiolabeled anti-ras p21 monoclonal antibodies.

Anti-ras p21 monoclonal antibody (RASK-3) was used for immunoscintigraphy of human cancer cell lines in nude mice. Iodine-125-labeled RASK-3 was injected into nude mice with either human colon cancers (FCC-1 or BM-314) or lung cancer (KNS-62). Clear images were obtained in all three cancers 7 days after the injection of antibody. No localization of 125I-labeled control monoclonal antibody was observed. The ratio of tissue/blood radioactivity and % ID/g in the tumor were significantly higher than other organs by Day 8. The specific localization index examined by 131I-RASK-3 and 125I-control monoclonal antibody was also higher in the tumor than in other tissues. In the in vitro study, binding of RASK-3 to tumor cells increased significantly by treatment of cells with either lysolecithin or periodate-lysine-paraformaldehyde, which confirmed the intracellular localization of ras p21. The mechanism by which anti-ras p21 antibodies accumulate in tumor sites could be the necrotic changes in tumor cells or changes in membrane permeability of non-necrotic cells. These results provide a strong rationale for the utilization of ras p21 as a target antigen in the imaging of a variety of human cancers.

Animals↗
PubMed1989

A biotin-avidin sandwich ELISA for quantification of intact complement component C9. The sera from hereditary C9 deficient individuals completely lack C9.

A two-site sandwich ELISA method was developed for quantitating intact C9 protein using MoAb P40 (anti-C9b antibody). This antibody reacted with monomeric C9 but not with polymerized C9. MoAb P40 was used as a capture antibody and MoAb X195 (anti-C9a antibody) as a detection antibody. This method is highly sensitive and can detect approximately 0.5 ng/ml of native C9. No cross-reactivities of either C6, C7, or C8 were observed even at concentrations of 10 micrograms/ml per component. In addition, this method allows for measurement of only intact C9 molecules, eliminating the interference of polymerized C9 or inactivated C9. Using this assay, no C9 at all was detected in sera from inherited C9 deficient individuals, including both healthy blood donors and patients with meningococcal meningitis; although by hemolytic assay, C9 levels were reported to be less than 0.2% those of NHS. Therefore, this two-site sandwich ELISA method can replace the hemolytic assay, and is especially useful for measuring small amounts of C9 in serum.

Animals↗
PubMed1989

Cooperation of synthetic insulin-like growth factor I/somatomedin C and 1,25-dihydroxyvitamin D3 on regulation of function in clonal osteoblastic cells.

We investigated the effects of insulin-like growth factor I/somatomedin C (IGF-I/SM-C), and the interaction of IGF-I and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on mouse clonal osteoblasts, MC3T3-E1. IGF-I stimulated [3H]thymidine incorporation into the DNA of the cells at concentrations of 1.3-130 X 10(-9) M. The alkaline phosphatase (ALP) activity in cultures was also raised by the hormone at the same concentrations. The optimal dose of IGF-I was 13 X 10(-9) M. Co-addition of IGF-I (1.3-130 X 10(-9) M) and 1,25(OH)2D3 (10(-11) to 10(-10) M) to the culture of MC3T3-E1 cells caused a synergistic increase in ALP activity. 25(OH)D3 and 24,25(OH)2D3 showed a similar effect with IGF-I at 1000-2000 times higher concentrations than 1,25(OH)2D3. [3H]Proline incorporation into collagenase digestible protein (CDP) in media was stimulated dose-dependently by IGF-I up to 2.2-fold over the control levels at 130 X 10(-9) M. Addition of 1,25(OH)2D3 (5 X 10(-11) M) and IGF-I further elevated the proline incorporation into CDP. However, the increment in CDP synthesis, induced by the two hormones was less than the increment in ALP activity. Thus, we conclude (1) that IGF-I stimulates both cell replication and differentiated functions in cultured murine osteoblasts and (2) that IGF-I and 1,25(OH)2D3 have the synergistic effect on ALP activity and the additive effect on collagen synthesis in MC3T3-E1 cells.

Alkaline Phosphatase↗
PubMed1989

Effect of single oral phosphate loading on vitamin D metabolites in normal subjects and in X-linked hypophosphatemic rickets.

There have been several reports that document abnormal vitamin D metabolism in X-linked hypophosphatemic rickets (XLH). Those reports indicate a blunted renal 25-hydroxyvitamin D-1 alpha-hydroxylase response to a potent stimulator, phosphorus restriction. We examined here its response to phosphate supplementation. Seven normal volunteers and 12 patients with XLH were submitted to single oral phosphate loading. This treatment produced a marked elevation of the serum phosphorus level, with a mild reduction in the serum calcium level. In normal subjects, although the concentrations of intact parathyroid hormone and mid-region parathyroid hormone were increased, with two peaks at 2 and 8 h after treatment, there were no significant changes in vitamin D metabolites including 25-hydroxyvitamin D (25(OH)D), 24,25-dihydroxyvitamin D (24,25(OH)2D) and 1,25-dihydroxyvitamin D (1,25(OH)2D). On the other hand, in the patients with XLH, the serum 1,25(OH)2D level increased from 23.4 +/- 12.0 (mean +/- SD) pg/ml to 44.3 +/- 33.6 pg/ml 6 h after ingestion without any significant change in 25(OH)D or 24,25(OH)2D.

24,25-Dihydroxyvitamin D 3↗
PubMed1989

[Changes of alveolar macrophage plasminogen activator in rats exposed to nitrogen dioxide].

In order to clarify the role of nitrogen dioxide (NO2) in the development of lung injury, male Wistar rats were exposed continuously to 0.3 or 5.0 ppm NO2 for 10, 20, 30, 60 and 90 days, and alveolar macrophages and lavage fluid obtained by bronchoalveolar lavage were examined. The results were as follows: 1) The number of alveolar macrophages increased significantly in response to NO2 exposure. Throughout the whole test period, the largest number was obtained in the group exposed to 5.0 ppm, followed by the group exposed to 0.3 ppm, and then by the control group. 2) The plasminogen activator (PA) released from alveolar macrophages was increased dose-dependently by NO2 exposure. The activities were significantly high in the groups exposed for 10 to 20 days at each concentration, and then slightly decreased at 30 days. Thereafter, activity showed a tendency to increase, reaching the maximum level on the 60th day of exposure. 3) Similarly, the fibrinolytic activity in the lavage fluid was increased dose-dependently by NO2 exposure. The maximum activity was noted on the 10th day of exposure, followed by a rapid decrease up to the 30th day, and a slight rise again between the 60th and 90th day. 4) In the group exposed to 5.0 ppm NO2, total protein in the lavage fluid increased, and the elastase inhibitory capacity (EIC) per milligram of protein decreased. In the group exposed to 0.3 ppm NO2, however, no difference from the control group was noted. These results revealed that the alveolar macrophages were affected and increased PA activity as a result of exposure to as little as 0.3 ppm NO2. This was shown to result in an increase of the fibrinolytic activity in the alveoli, leading to damage to the lung tissue. This evidence may explain the morphological findings of the appearance of emphysematous change in the lungs of rats exposed to low levels of NO2. For the detection of the effect of NO2 on the lung tissue, PA appears to be a more sensitive indicator than EIC.

Animals↗
PubMed1989

An arginine to cysteine amino acid substitution at a critical thrombin cleavage site in a dysfunctional factor VIII molecule.

We have analyzed the factor VIII (FVIII) protein and the nucleotide sequence around two thrombin cleavage sites, at arginine 372 in the FVIII heavy chain and arginine 1689 in the FVIII light chain in a naturally occurring dysfunctional FVIII variant, FVIII Okayama. The patient was a 42-year-old hemophiliac with a FVIII coagulant activity of 0.03 U/mL and a FVIII antigen level of 0.8 U/mL. The patient's FVIII was not thrombin activatable to levels seen in normal plasma. Immunoblotting of partially purified FVIII Okayama and normal FVIII showed that thrombin cleavage of the 92 kilodalton (Kd) heavy chain was impaired in the mutant protein. The patient's genomic DNA was amplified using the polymerase chain reaction with two sets of synthetic oligonucleotide primers spanning amino acid residues 319 to 400 and 1630 to 1720. Sequence analysis of the amplified DNA fragments revealed a cytosine to thymine transition, converting an arginine to a cysteine codon at residue 372. No abnormality was found in the FVIII light chain region analyzed. The patient's hemophilic brother and carrier mother revealed the same mutation. We conclude that the pathogenesis of hemophilia A in this patient is probably due to an arginine to cysteine substitution at a thrombin cleavage site in the FVIII heavy chain.

Adult↗
PubMed1989

[Properties of factor VIII/von Willebrand factor in two highly-purified factor VIII concentrates, Hemofil M and Monoclate, using monoclonal antibodies].

Properties of F. VIII/vWF in highly-purified factor VIII concentrates were examined using monoclonal antibodies. The F. VIII: C levels obtained with the chromogenic assay agreed with those obtained with the one-stage clotting method. The ratio between F. VIII: Ag and F. VII: C in Hemofil M and Monoclate was 1.09 and 1.34, respectively. The F. VIII: Ag levels assayed by monoclonal ELISAs were the same as those assayed by polyclonal ELISA, except that those assayed by C 5-ELISA tended to be higher. The ratio between F. VIII: Ag and vWF: Ag in Hemofil M and Monoclate was 105 and 45, respectively. Both concentrates lacked the large multimers of vWF and showed the intensification of the satellite bands. SDS-PAGE patterns showed almost no contamination. Immunoblot analysis revealed that F. VIII in both concentrates could react with 6 kinds of monoclonal antibodies to F. VIII. These results suggest that the fundamental structure of F. VIII molecule for coagulant activity in both concentrates are preserved.

Antibodies, Monoclonal↗
PubMed1988

Structure of the von Willebrand factor domain interacting with glycoprotein Ib.

von Willebrand factor is a multifunctional adhesive protein of plasma, platelets, and endothelial cells that mediates a crucial interaction for normal hemostasis and thrombus formation by binding to platelet membrane glycoprotein Ib. We provide here evidence that this function involves two limited noncontiguous regions of the molecule, each contained within 15 amino acid residues, separated in the linear sequence by 205 residues, and maintained in close spatial proximity in the folded molecule by disulfide bonding. Definition of this chemical structure clarifies a fundamental mechanism of platelet adhesion to thrombogenic surfaces and sets the bases for obtaining synthetic replicas that may be used to modulate platelet function.

Amino Acid Sequence↗
PubMed1988

Localization of the binding site for a factor VIII activity neutralizing antibody to amino acid residues Asp1663-Ser1669.

We have identified the Factor VIII amino acid sequence Asp-Tyr-Asp-Asp-Thr-Ile-Ser (1663-1669) as the binding site of a Factor VIII activity neutralizing antibody (28 Bethesda units/mg). The binding site of another neutralizing antibody (10 Bethesda units/mg) overlapped only at Asp1663 and Tyr1664, whereas an antibody with minimal neutralizing activity (0.2 Bethesda units/mg) bound only at Asp1665-Ser1669. Residues comprising antibody binding sites were determined by blocking Factor VIII neutralization and/or binding to insolubilized Factor VIII with overlapping peptides, or with variant peptides in which a single amino acid was deleted or replaced with glycine. Eight additional antibodies to flanking sequences, and with similar affinities for Factor VIII, had little or no neutralizing activity (0-3.0 Bethesda units/mg). These studies suggest that Asp1663 and Tyr1664 may be structural features important to Factor VIII function.

Amino Acid Sequence↗