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Biomedical subjects

F Suzuki

Publications and source records attributed to F Suzuki.

At least 361 records · Page 20Linked to original sources
PubMed1990

Depletion of macrophages expressing I-J antigen results in efficient generation of alloreactive cytotoxic T lymphocytes.

The role of suppressor macrophages (S-M phi) produced during generation of cytotoxic T lymphocytes (CTL) stimulated with allogeneic lymphocytes was investigated. Splenic CTL from C3H/He mice (H-2k) were generated by in vivo immunization and subsequent in vitro stimulation by splenic lymphocytes from C57B1/6 mice (H-2b) in mixed lymphocyte reaction (MLR). In addition to in vitro standard 51Cr release assay, the CTL activity was mainly measured in vivo using the Winn assay against EL-4 thymoma cells in B6C3F1 mice (H-2b/k). In mice injected with CTL plus EL-4 cells survival rate was 20% compared with no survival of mice treated with normal spleen cells plus EL-4 cells. The antitumor activity of the CTL was significantly increased when immunized mice were treated with a 5 mg/kg ip dose of indomethacin at the time of immunization (80% survival). Macrophages were depleted from spleen cells of immunized mice by plastic adherence or carbonyl-iron treatment, replaced with an equivalent number of M phi from normal mice, and then introduced into a 5-day MLR. When the antitumor activity of the cells isolated from this MLR was measured in the Winn assay, 90-100% survival in EL-4-bearing mice was observed. In contrast, none of the mice inoculated with EL-4 alone and 20% of the mice that received CTL obtained after alloimmunization followed by MLR in addition to EL-4 survived. These results of CTL activity were confirmed by in vitro cytotoxicity tests. When the M phi isolated from spleens of immunized mice were analyzed for I-Jk antigen expression, a 2.5-fold increase was detected, compared with splenic M phi obtained from normal C3H/He mice. In contrast, Ia and I-Ak antigen expression was equivalent in M phi isolated from normal or immunized C3H/He mice. When immune spleen cells were treated with anti-I-Jk antiserum followed by complement and then, subjected to the MLR, the antitumor activity of CTL was significantly enhanced (80% survival). However, treatment of these cells with anti-I-Ak antiserum and complement did not alter CTL activity. These data suggest that the increase of S-M phi expressing I-Jk+ antigen to be induced during alloimmunization results in suppression of allospecific CTL-generation in MLR.

Animals↗
PubMed1990

1 alpha,25-dihydroxyvitamin D3 stimulates colony formation of chick embryo chondrocytes in soft agar.

The effect of vitamin D metabolites on the growth of chick embryo chondrocytes in soft agar was examined. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] at 10(-8)-10(-7) M induced colony formation by chick embryo chondrocytes in soft agar in the presence of 10% fetal bovine serum. Furthermore, 1,25(OH)2D3 increased the number of colonies in the presence of a maximal dose of basic fibroblast growth factor, a potent mitogen for chondrocytes in soft agar. However, 24R,25 (OH)2D3 and other metabolites had little effect on the soft agar growth of chondrocytes in the presence or absence of basic fibroblast growth factor. These results suggest that 1,25(OH)2D3 is an active metabolite which may be involved in supporting cartilage growth.

Agar↗
PubMed1990

Enhanced intestinal absorption of a hydrophobic polymer-conjugated protein drug, smancs, in an oily formulation.

Intestinal absorption of neocarzinostatin (NCS) and smancs (copolystyrene maleic acid-conjugated NCS), in aqueous and oily formulations, was investigated after oral administration in mice. Blood concentrations of NCS and smancs were determined with a cytotoxicity assay employing the highly sensitive Epstein-Barr (EB) virus-transformed B-lymphoblastoid cell line, TK/B. Smancs was more efficiently absorbed from a medium-chain triglyceride solution (oily smancs) than from an aqueous solution in phosphate-buffered saline (PBS). The maximum blood concentration and the area under the concentration curve versus time course (AUC) of oily smancs were 9 and 11 times greater than those of the aqueous form of smancs, respectively. At 5 hr after administration of oily smancs, 0.044% of the total smancs dose was found in blood, whereas the parent compound NCS was not detectable at any time. When oily smancs was administered orally to sarcoma 180 tumor-bearing mice, a selective accumulation of smancs in tumor tissue was observed. These results indicated that a biologically active protein, which cannot be used orally, may be rendered orally active drug by conjugation with a hydrophobic polymer in combination with an oily formulation.

Administration, Oral↗
PubMed1990

Role of 1,25-dihydroxycholecalciferol in growth-plate cartilage: inhibition of terminal differentiation of chondrocytes in vitro and in vivo.

The effects of vitamin D metabolites on alkaline phosphatase [ALPase; orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] activity, a marker of terminal differentiation, in chondrocyte cultures and growth plates in vivo were examined. In cultures of pelleted rabbit growth-plate chondrocytes, 1,25-dihydroxycholecalciferol (1,25-dihydroxyvitamin D3) increased the contents of DNA and macromolecules containing uronic acid (proteoglycans). It also decreased ALPase activity with an ED50 of less than 1 nM. Other vitamin D3 metabolites, such as 24,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol, had little effect on these biochemical parameters. In rachitic growth plates, the uronic acid content was half that in normal growth plates, whereas ALPase activity was 2.5 times that in normal growth plates. Administration of 1,25-dihydroxycholecalciferol at a low dose (0.1 micrograms per kg of body weight) to rachitic rats increased the uronic acid content 1.4-fold and decreased ALPase activity by 40%. This compound, like 24,25-dihydroxycholecalciferol (10 micrograms per kg of body weight), increased the calcium level of the blood. However, administration of 24,25-dihydroxycholecalciferol had little effect on the uronic acid and ALPase contents in growth plates. These observations suggest that 1,25-dihydroxycholecalciferol is a bioactive form of vitamin D that plays an important role in the control of chondrocyte terminal differentiation.

24,25-Dihydroxyvitamin D 3↗
PubMed1990

Hamster cell line suitable for transfection assay of transforming genes.

We established a subclone, SHOK, from the GHE-L cell line, an immortal line derived from a primary culture of Syrian hamster embryo cells, as a recipient cell line useful for the detection of oncogenes by transfection. SHOK cells were almost as susceptible as NIH 3T3 cells to focus formation by many oncogenes, including v-raf, v-Ha-ras, v-Ki-ras, or activated c-Ha-ras. The susceptibility of SHOK to focus formation was higher than that of NIH 3T3 for v-mos but was lower for v-fps, v-fgr, v-src, v-sis, and v-abl. When DNAs extracted from 27 human and murine tumors were tested for focus formation, 5 DNAs were positive in NIH 3T3 cells, whereas 9 were positive in SHOK cells at the primary transfection. Using SHOK cells as recipients of tumor cellular DNA, we isolated another oncogene and a c-Ki-ras2 gene mutated at codon 146 that were difficult to detect in NIH 3T3 cells. SHOK cells have a low rate of spontaneous transformation, produce easily distinguishable foci, and maintain a stable karyotype in transformed cells. In addition to being useful for the screening of human tumor DNAs, SHOK cells will be useful for the isolation of oncogenes from murine tumors because of their hamster origin.

Animals↗
PubMed1990

Physiological role of vitamin A in growth cartilage cells: low concentrations of retinoic acid strongly promote the proliferation of rabbit costal growth cartilage cells in culture.

We have demonstrated that high concentrations of retinoic acid (RA) inhibit expression of the differentiated phenotypes of rabbit costal chondrocytes in culture [M. Takigawa et al. (1980) Proc. Natl. Acad. Sci. U.S. 77, 1481-1485]. In this study we examined the effects of low concentrations of RA on rabbit costal chondrocytes cultured in medium containing vitamin A-deficient serum. In vitamin A-deficient medium, chondrocytes isolated from growth cartilage (GC) proliferated only very slowly, and RA strongly stimulated their proliferation. This stimulatory effect was observable at a concentration of 10(-10) M RA and maximal at a concentration of 10(-8) M. RA at 10(-8) M did not change GC cells from a typical polygonal shape to fibroblast-like cells or inhibit their synthesis of type II collagen. Moreover, RA-treated cells did not synthesize type I collagen. RA inhibited glycosaminoglycan (GAG) synthesis by the cells dose-dependently, but did not change the distribution profile of proteoglycan monomers as determined by glycerol gradient centrifugation. The inhibitory action of RA on GAG synthesis was reversible: after removal of RA from the culture, the rate of GAG synthesis increased within 2 days. In contrast, resting cartilage (RC) cells proliferated well in vitamin A-deficient medium without addition of RA, and RA (10(-8) M) stimulated their proliferation only slightly. Furthermore, the inhibitory effect of RA on GAG synthesis in RC cells was much weaker than that in GC cells. These observations suggest a physiological role of RA in cartilage in stimulating the proliferation of GC cells without causing drastic change in their differentiated phenotypes.

Animals↗
PubMed1990

Androgen dependence and tissue specificity of renin messenger RNA expression in mice.

Testosterone, a steroid hormone which increases blood pressure by hitherto unknown mechanisms, is known to induce renin synthesis in the submandibular gland (SMG) of mice. Since renin as well as all other components of the renin-angiotensin system are present in organs important for cardiovascular control, e.g. the kidney, heart, adrenal gland and brain, it is of interest to study the effect of testosterone on renin gene expression in these organs. Renin messenger (m) RNA concentrations were measured by a solution hybridization assay using a 32P-labeled mouse SMG renin complementary (c) RNA as a radioactive probe (detection limit: 1 pg renin mRNA). Measurements were performed after 2 h and after 2, 7, 14 and 21 days of dihydrotestosterone (DHT) treatment in female NMRI mice. Renin mRNA concentration (values are expressed as pg renin mRNA/ micrograms total RNA) in the SMG was significantly increased after 7 days (108 +/- 22 in controls versus 630 +/- 101 in DHT-treated mice), after 14 days (83 +/- 15 in controls versus 743 +/- 83 in DHT-treated mice) and after 21 days (107 +/- 30 in controls versus 579 +/- 76 in DHT-treated mice), but did not reach levels found in untreated male NMRI mice (1021 +/- 84). In the kidney, a decrease was observed within 21 days, from 43 +/- 4 and 40 +/- 4 to 29 +/- 2 and 22 +/- 1.7 pg/micrograms in controls and DHT-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1990

Selective increase in S-100 beta protein by aging in rat cerebral cortex.

Changes in the concentrations of nervous tissue-related proteins and their isoproteins, such as S-100 proteins (S-100 alpha and S-100 beta), enolase isozymes (alpha-enolase and gamma-enolase), and GTP-binding proteins (Go alpha, Gi2 alpha, and beta-subunits), were determined in the CNS of male rats of various ages (from 2 to 30 months old) by means of enzyme immunoassay. The weights of brains and the concentrations of soluble proteins in the cerebral cortex, cerebellum, and brainstem were constant during the observation period. The concentration of S-100 beta protein, which is predominantly localized in glial cells, increased gradually in the cerebral cortex with age; levels in the 25-month-old rats increased to approximately 150% of the levels in the young (2-month-old) rats. However, the S-100 beta concentrations in the cerebellum and brainstem were relatively constant, showing similar values in rats 2-30 months old. Levels of other proteins, including both neuronal (gamma-enolase and Go alpha) and glial (alpha-enolase and S-100 alpha) marker proteins, did not change significantly with age in the cerebral cortex, cerebellum, and brainstem. These results suggest that there is a close relation between the age-dependent changes of the CNS function and S-100 beta protein levels in the cerebral cortex.

Aging↗
PubMed1990

Potent mitogenic effects of parathyroid hormone (PTH) on embryonic chick and rabbit chondrocytes. Differential effects of age on growth, proteoglycan, and cyclic AMP responses of chondrocytes to PTH.

The effect of PTH on chondrocyte proliferation as a function of cartilage age was examined. PTH[1-34] induced a 12- to 15-fold increase in the efficiency of colony formation in soft agar by chondrocytes from embryonic 13- to 19-d-old chickens and fetal 25-d-old rabbits with a 10-fold increase in their DNA content. It also caused a 2.5-fold increase in [3H]thymidine incorporation into DNA in fetal 25-d-old rabbit chondrocytes. No mitogenic responses to PTH were observed, however, in postnatal 7- to 21-d-old chick chondrocytes or postnatal 21-d-old rabbit chondrocytes. This age dependency was observed only with PTH: fibroblast growth factor, epidermal growth factor, and insulin stimulated chondrocyte proliferation irrespective of cartilage age. The absence of a mitogenic effect in postnatal chondrocytes was not due to a decrease in number or a reduction in affinity of receptors for PTH. PTH also increased [35S]sulfate incorporation into proteoglycans and the cyclic AMP level in fetal and postnatal chondrocytes, but at 100-fold higher concentrations (10(-8)-10(-7) M) than those (10(-10)-10(-9) M) required for the stimulation of cell division. These results suggest that PTH is a potent mitogen for embryonic chondrocytes, and that its mitogenic effect disappears selectively after birth.

Age Factors↗
PubMed1990

Stimulation of proteoglycan and DNA syntheses in chondrocytes by centrifugation.

So that the effects of biomechanical forces on the proliferation of chondrocytes and their proteoglycan synthesis could be studied, growth-plate and articular chondrocytes were maintained separately as packed masses in centrifuge tubes in the presence of 10% serum. In these conditions, the cells became re-organized into cartilaginous tissue in seven days. After ten days, they were centrifuged at gravities (g) of 1.3-27 for 24 h in a CO2 incubator. Control cells were maintained in the CO2 incubator without centrifugation. Centrifugation of growth-plate chondrocytes at 3 g resulted in a two-fold increase in incorporation of [35S]sulfate into proteoglycans, but had little effect on their [3H]thymidine incorporation into DNA. On the other hand, centrifugation of articular chondrocytes at 3 g for 24 h caused 1.5-fold increases in both [35S]sulfate incorporation into proteoglycans and [3H]thymidine incorporation into DNA. These results suggest that biomechanical forces have different effects on the growth and differentiation of articular and growth-plate chondrocytes.

Animals↗
PubMed1990

Effects of parathyroid hormone and calcitonin on alkaline phosphatase activity and matrix calcification in rabbit growth-plate chondrocyte cultures.

The effects of PTH and calcitonin (CT) on the expression of mineralization-related phenotypes by chondrocytes were examined. In cultures of pelleted growth-plate chondrocytes. PTH caused 60-90% decreases in alkaline phosphatase activity, the incorporation of 45Ca into insoluble material, and the calcium content during the post-mitotic stage. These effects of PTH were dose-dependent and reversible. In contrast, CT increased alkaline phosphatase activity, 45Ca incorporation into insoluble material, and the calcium content by 1.4- to 1.8-fold. These observations suggest that PTH directly inhibits the expression of the mineralization-related phenotypes by growth-plate chondrocytes, and that CT has the opposite effects.

Alkaline Phosphatase↗
PubMed1990

Highly sensitive microplate-ELISA for angiotensin I using 3,3', 5,5'-tetramethylbenzidine.

A microplate-ELISA was established for angiotensin (Ang) I using Ang I-peroxidase conjugate, antiAng I antibodies which could distinguish Ang I from Ang II and Ang III, and 3,3', 5,5'-tetramethylbenzidine. Ang I could be quantified in amounts as low as 1 pg by the spectrophotometric method. The present assay system was the most sensitive and rapid in all Ang I assay systems described so far. The assay system was applicable to determination of Ang I concentration in human plasma and abdominal fluid.

Adult↗
PubMed1990

Aspartyl- and glutamyl-lysine crosslinks formation and their nutritional availability.

Transglutaminase-catalyzed incorporation of L-lysine into wheat gliadin rendered the lysine-fortified protein poorly digestible in the in vitro tests. In rat feeding tests, however, the luminal leavings and excreta collected after administration of the [14C]lysine-fortified gliadin contained less than one-tenth of the radioactivity originally administered to rats. The enzymes, gamma-glutamylamine cyclotransferase and 5-oxoprolinase, known to occur in animal kidney are at least in part responsible for the observed high availability of isopeptide bound lysine. A novel enzyme which is capable of directly hydrolyzing the cross-linked isopeptide into component amino acids and peptides, "N epsilon-(gamma-glutamyl)lysine hydrolase" was found in the isolated microorganisms which can use the synthesized N epsilon-(gamma-glutamyl)lysine as their only source of carbon and nitrogen. The enzyme(s) appear to be effectively used for improving digestibility and availability of protein matrixes formed in normal metabolism and by heat and/or shear treatment commonly used in food processing.

Animals↗
PubMed1990

Ren-2 as well as Ren-1 renin exists in the kidney and plasma of a two-renin gene mouse.

Ren-1 renin is synthesized in the kidney of every mouse. Ren-2 renin has been observed in the submandibular gland (SMG) of male mice carrying two renin genes. However, it is not known if Ren-2 renin is in the kidney and blood of the two-renin gene mice. In this study, a direct ELISA for Ren-2 renin (SMG renin) was established by a sandwich method. This ELISA could measure the Ren-2 active renin in the range from 1 to 100 ng and distinguish Ren-2 active from not only Ren-1 renin but also Ren-2 prorenin. By a combination of this assay system and conventional methods, the pro-form as well as the active form of Ren-2 renin was found in the kidney and plasma of male AKR mice carrying two-renin genes.

Animals↗
PubMed1990

[A case report of esophageal intramural pseudodiverticulosis].

A 76 year old man with esophageal intramural pseudodiverticulosis occurring in reflux esophagitis is presented. This unusual condition characterized by multiple small outpouchings in the esophageal wall and associated with a high incidence of benign esophageal stricture. Our case demonstrated typical radiological feature by barium swallow.

Aged↗
PubMed1990

[Investigation of adsorption, metabolism and excretion of cefuroxime axetil in volunteers of gastrectomized patients].

Adsorption, metabolism and excretion (ADME) of cefuroxime axetil (CXM-AX) 500 mg given orally at 30 minutes after meals to male volunteers who had undergone gastrectomy was compared with that of healthy volunteers. 1. The transition of the drug's serum concentrations was observed as follows: Tmax was somewhat shorter and T 1/2 longer in the gastrectomized volunteer group than in the healthy volunteer group. 2. Total urinary recovery rates of cefuroxime (CXM) were not significantly different between the 2 groups, averaging 53.6% for the gastrectomized volunteer group and averaging 54.5% for the healthy volunteer group. 3. Total urinary recovery rates of CXM-delta 2 were not significantly different between the 2 groups either, averaging 1.7% for the gastrectomized volunteer group and 1.3% for the healthy volunteer group. 4. The above results suggest that ADME of CXM-AX in the gastrectomized volunteers is not fundamentally different from that of the healthy volunteers. The absorption, however, may be reduced when peristalsis of the intestinal tract is accelerated as a result of gastrectomy.

Administration, Oral↗
PubMed1990

[Multiple malignant schwannoma treated with a multidisciplinary therapy--a case report].

A 32-year-old man, complaining of an abdominal mass, was admitted to hospital where, on undergoing examination, the mass, which had spread widely through the abdominal cavity and the retroperitoneal space, was diagnosed as a malignant schwannoma with a liver metastasis. Thus, a multidisciplinary treatment was initiated and a remission was achieved. Later, however, he developed a multiple, local recurrence and died forty months after onset of his clinical symptoms. Since the prognosis of patients with a malignant schwannoma that do not undergo radical surgery is extremely poor, the authors emphasize the necessity of research for an effective adjuvant therapy.

Adult↗