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Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 19 recordsLinked to original sources
PubMed1992

Interleukin 6/B cell stimulatory factor-II is expressed and released by normal and transformed human bronchial epithelial cells.

Airway epithelial cells have a potential to participate in local immune and inflammatory responses via releasing biologically active compounds. We studied the expression and release of interleukin 6 (IL-6), a multifunctional cytokine possibly involved in tissue immune responses. Primary culture of normal human bronchial epithelial cells and its transformed cell line BEAS-2B released significant amount of biologically and immunologically intact IL-6 into media. A protein synthesis inhibitor cycloheximide abolished the IL-6 release, suggesting a de novo synthesis. Northern blot analysis demonstrated the expression of the specific IL-6 mRNA. Human bronchial epithelial cells can produce IL-6 and contribute to the local activity of IL-6, suggesting that these cells may play a role in the regulation of airway immune responses.

Antibodies, Monoclonal↗
PubMed1992

Augmentation of transient low-threshold Ca2+ current induced by GTP-binding protein signal transduction system in GH3 pituitary cells.

We characterized the effects of thyrotropin-releasing hormone (TRH; 500 nM) and guanosine 5'-0-3-thiotriphosphate (GTP gamma S; 50 microM) on two types of Ca2+ currents in pituitary-hormone-secretory GH3 cells and were surprised to find marked increases in transient, low-threshold Ca2+ currents (T currents) induced by extracellularly applied TRH or intracellularly applied GTP gamma S. The effect of TRH was blocked by intracellularly applied guanosine 5'-0-2-thiodiphosphate (GDP beta S; 100 microM). The increase in the T current was found to be accompanied by a decrease in long-lasting, high-threshold Ca2+ current (L-current), in response to both TRH or GTP gamma S. These indicate that the enhancement of Ca2+ influx by TRH (500 nM) is largely conferred by T currents in GH3 cells. A reduced concentration of TRH (5 nM) still markedly increased the T current, but failed to decrease the L current. These data suggest that the augmentation of the T currents as well as depression of the L currents by TRH (500 nM), through the activation of a GTP-binding protein, may constitute an important regulatory mechanism of sustained pituitary hormone secretion in GH3 cells.

Animals↗
PubMed1992

Regulation of endothelin-1 synthesis in cultured guinea pig airway epithelial cells by various cytokines.

To study regulatory mechanisms influencing the synthesis and release of ET-1, a potent bronchoconstrictor, epithelial cells from guinea pig tracheas were cultured to test various cytokines for the synthesis of ET-1 and its precursor, big ET-1. Cytokines tested were divided into 4 groups, based on their potential modes of action. IL-8, TNF alpha and TGF beta transiently increased the synthesis of ET-1, while EGF, PDGF and GM/CSF promoted proliferation of ET-1 synthesizing cells. IL-1 enhanced the synthesis of ET-1 precursor without mitogenesis, whereas IL-2, IL-6 and IGF-1 induced both the synthesis of big ET-1 and mitogenesis. These observations suggest that cytokines involved in damage, inflammation and repair of the airway epithelial layer regulate the synthesis and release of ET-1 by multiple mechanisms, thereby influencing airway muscle tone.

Animals↗
PubMed1992

Effects of locus ceruleus lesions on the pericapillary nerve terminals in the feline brain.

The effects of bilateral locus ceruleus (LC) lesions on the pericapillary nerve terminals were investigated in the feline brain parenchyma using electron microscopy. LC lesions were induced stereotaxically and the animals were sacrificed after intravenous administration of 5-hydroxydopamine (5-OHDA). The diameter and number of dense-cored vesicles (DCVs) and clear vesicles (CVs) in the pericapillary nerve terminals were measured. The number of DCVs in the nerve terminal was significantly decreased by bilateral LC lesions. The diameters of the DCVs and CVs decreased significantly as compared with those in the non-operated control group. These data suggest that the LC is closely related to the pericapillary nerve terminals in the brain parenchyma and that not only nerve terminals with DCVs but also those with CVs are affected by LC lesions.

Animals↗
PubMed1992

Dipyridamole enhances an anti-proliferative effect of interferon in various types of human tumor cells.

The anti-proliferative activity of human interferon (HuIFN) was enhanced by dipyridamole, 2,6-bis-(diethanolamino)-4,8-dipiperidinopyrimido-[5,4-d]-py rimidine, when tested against various human tumor cell lines, including KT (breast carcinoma), PLC/PRF/5 (hepatoma), MGC-I, U251-SP and T98 (glioma), HAC-2 and SHIN-3 (ovarian carcinoma), and MM-ICB (melanoma). The enhancement occurred irrespective of the kind of HuIFN used (alpha, beta or gamma) and the original degree of susceptibility of the cells to HuIFN. Even low doses down to 0.01 microM of dipyridamole that had no intrinsic anti-proliferative activity could enhance the effect of HuIFN. The enhancement of HuIFN effects seems not to be caused by induction of HuIFN production, because neither anti-viral activity nor HuIFN antigens were detected in culture medium in cells treated with dipyridamole. Mopidamole, a derivative of dipyridamole lacking one piperidine residue, produced little enhancement of the effects of HuIFN. Among ovarian cancer cell lines tested, the enhancement of the activity of HuIFN by dipyridamole for HAC-2 and SHIN-3 cells was equivalent to or greater than that for 3 chemotherapy agents (adriamycin, vincristine, and a camptothecin derivative). However, neither HOC-21 ovarian cancer cells nor HEC-1 endometrial adenocarcinoma cells were susceptible to any combinations. When MGC-1, U251-SP, and HAC-2 cells were injected into nude mice, the growth of tumors was more markedly inhibited by the subcutaneous administration of HuIFN in combination with oral administration of dipyridamole than by the HuIFN alone. Thus, this combination therapy seems to be worth trying for human cancer, although the enhancement of the effects of HuIFN by dipyridamole varied among the cell lines examined.

Animals↗
PubMed1992

Two classes of receptor specific for sperm-activating peptide III in sand-dollar spermatozoa.

We characterized receptors specific for sperm-activating peptide III (SAP-III: DSDSAQNLIQ) in spermatozoa of the sand dollar, Clypeaster japonicus, using both binding and cross-linking techniques. Analyses of the data obtained from the equilibrium binding of a radiolabeled SAP-III analogueto C. japonicus spermatozoa, using Klotz, Scatchard and Hill plots, showed the presence of two classes of receptors specific for SAP-III in the spermatozoa. One of the receptors (high-affinity) had a Kd of 3.4 nM and 3.4 x 10(4) binding sites/spermatozoon. The other receptor (low-affinity) had a Kd of 48 nM, with 6.1 x 10(4) binding sites/spermatozoon. The Kd of the high-affinity receptor was comparable to the median effective concentration of the intracellular-pH-increasing activity of SAP-III and that of the low-affinity receptor was comparable to the median effective concentration of the cellular-cGMP-elevating activity of the peptide. In addition, Scatchard and Hill plots of the data suggested the existence of positive cooperativity between the high-affinity members. Similar results were also obtained from a binding experiment using a sperm-membrane fraction prepared from C. japonicus spermatozoa. The incubation of intact spermatozoa or sperm plasma membranes with the radioiodinated SAP-III analogue and a chemical cross-linking reagent, disuccinimidyl suberate, resulted in the radiolabeling of three proteins with molecular masses of 126, 87 and 64 kDa, estimated by SDS/PAGE under reducing conditions.

Amino Acid Sequence↗
PubMed1992

Presence of gastrin-releasing peptide in neurons of the geniculate ganglion in rat and man.

Gastrin-releasing peptide (GRP) was demonstrated by immunohistochemistry and high-performance liquid chromatography to be present in the great majority of neurons in the geniculate ganglion of rat and man. This was in contrast to findings in the sphenopalatine ganglion of rat, where only little GRP was found, and in the otic, trigeminal, glossopharyngeal-vagal and internal carotid ganglia, where no GRP-containing cells could be demonstrated. The peptide was not detected by immunohistochemistry in nerve fibers within structures innervated from the ganglion (tongue, soft palate, retroauricular skin and facial musculature). The retrograde axonal tracer True blue accumulated in these neurons of rat after application not only in the tongue and soft palate but also in the retroauricular skin.

Animals↗
PubMed1992

Controlled ultraviolet irradiation generates endothelial damage without affecting the nerve terminals of the cerebral artery in cats.

The vesicles of adventitial autonomic nerve terminals were examined quantitatively under an electron microscope in controlled ultraviolet ray (UV)-irradiated cerebral vessels. Five cats whose basilar arteries were irradiated with UV (UV group) and 5 cats whose basilar arteries were irradiated with visible rays (control group) were compared. Endothelial vacuolation was observed only in the UV group. There was no statistically significant difference in the diameters of the dense-cored vesicles, related to noradrenaline, and clear vesicles, related to acetylcholine, between the two groups. It is concluded that controlled UV irradiation which generates endothelial damage does not affect the vascular adventitia ultrastructurally.

Acetylcholine↗
PubMed1992

Production of endothelin-1 and big-endothelin-1 by pleural mesothelial cells.

Immunoreactive endothelin-1 (ET-1) and big-endothelin-1 (big-ET-1) were detected in conditioned medium of cultured rat pleural mesothelial cells by using sensitive sandwich-type enzyme immunoassay. The amount of both ET-1 and big-ET-1 increased time-dependently. In both instances, maximal amount was detectable in conditioned medium obtained after 72 h in culture (ET-1: 117.1 +/- 30.1 pg/10(6) cells; big-ET-1: 2.4 +/- 2.1 pg/10(6) cells). Fetal calf serum markedly stimulated the production of both ET-1 and big-ET-1.

Animals↗
PubMed1992

Pituitary adenylate cyclase activating polypeptide provokes cultured rat chromaffin cells to secrete adrenaline.

Pituitary adenylate cyclase activating polypeptide (PACAP) provoked the rat chromaffin cells to secrete adrenaline. Within 20 min, the amount of adrenaline secreted by PACAP (10(-8) M) was as much as that caused by acetylcholine (10(-4) M). PACAP, but not acetylcholine, induced a long-term (over 120 min) increase in secretion of adrenaline. PACAP also activated adenylate cyclase and elevated cytosolic Ca2+ concentration. Furthermore, we found immunoreactive PACAP and PACAP binding sites in the rat adrenal medulla. These results suggest that PACAP has an important role in stimulating secretion of adrenaline in the adrenal medulla.

Adrenal Cortex↗
PubMed1992

Brain maturation and response to anoxia: 31P NMR spectroscopic studies in rat pups.

The differential effects of systemic anoxia on the immature rat brain in two postnatal developmental age groups, group I (1-2 days postnatal) and group II (9-10 days postnatal), were studied utilizing phosphorus-31 nuclear magnetic resonance spectroscopy. While all pups in group I survived the 15-min anoxic period, only half of the pups in group II survived. Brain adenosine triphosphate and intracellular pH of pups in group I remained essentially unchanged throughout the anoxic period, while phosphocreatine and inorganic phosphate were sensitive indicators of anoxia. These parameters were all more drastically affected in group II pups than in group I pups. Group II pups also exhibited a significant increase in phosphomonoester, indicating developmental differences in phospholipid metabolism.

Adenosine Triphosphate↗
PubMed1992

Vasoactive intestinal polypeptide and acetylcholine coexist with neuropeptide Y, dopamine-beta-hydroxylase, tyrosine hydroxylase, substance P or calcitonin gene-related peptide in neuronal subpopulations in cranial parasympathetic ganglia of rat.

Immunohistochemistry has been used to demonstrate that neuropeptide Y, dopamine-beta-hydroxylase, calcitonin gene-related peptide or substance P are colocalized with vasoactive intestinal polypeptide and choline acetyltransferase in subpopulations of neurons in cranial parasympathetic ganglia of rat. These comprise the ciliary, sphenopalatine, otic, glossopharyngeal-vagal and internal carotid ganglia. In the ciliary and glossopharyngeal-vagal ganglia tyrosine hydroxylase is also found in such neurons. The findings emphasize that the combined localization of dopamine-beta-hydroxylase and neuropeptide Y or the presence of tyrosine hydroxylase is not exclusively a marker for peripheral adrenergic neurons. Further, the co-localization of calcitonin gene-related peptide and substance P is not a decisive indication that a neuron is sensory in nature. It is discussed whether the presence of the enzymes and peptides other than vasoactive intestinal polypeptide is a remnant of a different expression during ontogenesis or indicates target-specific functions in the adult.

Acetylcholine↗
PubMed1992

Effects of reactive oxygen intermediate scavengers on the antitoxoplasmic activity of activated macrophages.

Obioactin, Lonomycin A, muramyl dipeptide, and scavengers of hydrogen radicals and of singlet oxygen were used to study the participation of.OH and 1O2 in the killing of Toxoplasma in cultures of glycogen-induced peritoneal macrophages. Both the scavengers of OH (diazabicyclooctane and histidine) and those of 1O2 (mannitol and sodium benzoate) failed to inhibit the multiplication of Toxoplasma in macrophages that were incubated with either Obioactin, Lonomycin A, or MDP. The results of these experiments demonstrate the apparent lack of an inhibitory effect of.OH and 1O2 on the multiplication of Toxoplasma, whereas the scavengers alone inhibited the growth of the parasites.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Sonographic imaging of the thyroid gland in congenital hypothyroidism.

We have attempted to facilitate differential diagnosis of etiological types of congenital hypothyroidism using real-time ultrasonography. Sonography of the thyroid gland was performed on 418 normal children, and 23 patients with congenital hypothyroidism and hyperthyrotropinemia. The thyroid gland was imaged by transverse scanning at the neck; the maximum thickness and the maximum width of the right and left lobe were measured. On the basis of the normal thyroid gland size obtained from normal children, the thyroid gland image of the patients were classified into 4 types: large image, normal image, small image, and no image of the thyroid gland at the neck: no image of the thyroid gland indicated agenesis or ectopia; large thyroid gland image indicated goitorous hypothyroidism. On the other hand, normal or small thyroid gland image probably included mild or transient forms of hypothyroidism, and transient hyperthyrotropinemia; these 2 types required further examination to complete the diagnosis. We concluded that real-time ultrasonography of the thyroid gland was a useful diagnostic imaging technic for patients who revealed elevated serum thyrotropin on neonatal mass-screening.

Adolescent↗
PubMed1992

Vaginal schwannoma.

In the patient reported here, a solid tumor lying between the vagina and the rectum was detected using various imaging techniques (ultrasonography and MRI), and S100 protein was found in the tumor cells. Thus, a schwannoma was the final diagnosis. This is a slow-growing neoplasm, and its early detection is difficult.

Female↗
PubMed1992

Experimental study on the effects of sclerosants for esophageal varices on blood coagulation, fibrinolysis and systemic hemodynamics.

The effects of five sclerosants used for treating esophageal varices on blood coagulation and fibrinolysis, systemic hemodynamics, and vascular endothelial cells were studied in mongrel dogs. With each sclerosant, hemolysis and a decrease in the platelet count were observed. Changes in the blood coagulation system occurred immediately after sclerosant administration. Prolongation of the PT and APTT and decreases in fibrinogen and alpha 2-PI were seen in the thrombin (TH), sodium tetradecyl sulfate (STS), and ethanolamine oleate (EO) groups. Polidocanol (PO) and absolute ethanol (ET) had less pronounced effects on these systems. A transient decrease in the cardiac index (CI), pulmonary artery pressure (PAP) and pulmonary artery resistance (PAR) was observed with the administration of the sclerosants, especially in the TH and STS groups. Excessive vascular endothelial damage was observed in the ET group, marked damage was seen in the EO and STS groups and slight damage was recorded in the PO and TH groups.

Animals↗