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Biomedical subjects

Y Ninomiya

Publications and source records attributed to Y Ninomiya.

At least 253 records · Page 14Linked to original sources
PubMed1989

The problem of hemoglobin switching in premature infants and IUGR infants.

Understanding the hemoglobin switching regulation mechanism in extremely premature infants is particularly important for understanding the extrauterine adaptation of the infants. In this study, we sought to identify factors influencing oxygen affinity in fetal blood and neonatal blood and obtained these results. (1) Aging is required for hemoglobin switching. (2) Switching in premature infants (27 to 32 weeks) is delayed at least 3 weeks in comparison with full-term infants. (3) A delay in the switching of fetal hemoglobin to adult hemoglobin was confirmed in IUGR (intrauterine growth retardation) infants. However, there is a compensatory increase in 2, 3-DPG for adaptation after birth. (4) A delay in 2, 3-DPG increase was observed in RDS (respiratory distress syndrome) infants, and oxygen affinity remained high.

2,3-Diphosphoglycerate↗
PubMed1989

Serum angiotensin converting enzyme activity in type 2 (non-insulin-dependent) diabetic patients with chronic glomerulonephritis.

To determine the value of measuring serum angiotensin converting enzyme (ACE) activity in type 2 (non-insulin-dependent) diabetic patients who have proteinuria, 19 diabetic patients with chronic glomerulonephritis (CGN), 20 diabetic patients with diabetic glomerulosclerosis and 20 healthy controls were studied. Serum ACE activity was significantly (p less than 0.01) higher in patients with diabetic glomerulosclerosis (26.7 +/- 4.9), while in patients with CGN it was comparable to that in healthy controls (21.5 +/- 3.5, 19.1 +/- 4.7, respectively). These results suggest that measurement of serum ACE activity may be useful in differentiating between diabetic glomerulosclerosis and CGN in type 2 diabetic patients who have proteinuria.

Diabetes Mellitus, Type 2↗
PubMed1989

Renal effects of prostaglandin E1 in type 2 (non-insulin-dependent) diabetic patients with subclinical nephropathy.

To determine whether the urinary albumin excretion rate (UAER) could be reduced without adversely affecting renal function, prostaglandin E1 (PGE1) was administrated to Type 2 (non-insulin-dependent) diabetic patients with both high and low microalbuminuria, who were matched for age, weight, height and hemoglobin A1c levels. The study was performed as a randomized double-blind trial, with the patients receiving either PGE1 or placebo. In patients who initially had a UAER above 30 mug/min (high UAER group), the UAER was significantly (p less than 0.01) reduced by the administration of PGE1. In this group the UAER after stopping PGE1 administration was comparable to baseline values. During PGE1 administration in the high UAER group, the filtration fraction (FF) was significantly reduced (p less than 0.01) while the glomerular filtration rate (GFR) was unchanged. In patients with an initial UAER below 30 mug/min (low UAER group) the UAER was not altered during the administration of PGE1. In this low UAER group both the FF and GFR remained unchanged. The urinary beta2-microglobulin excretion rate did not change significantly during the administration of PGE1 in either group. These results suggest that the decreased UAER in patients with an abnormally high albumin excretion, may be due to a change in the glomerular permeability to albumin related to a decreased FF.

Albuminuria↗
PubMed1988

The type X collagen gene. Intron sequences split the 5'-untranslated region and separate the coding regions for the non-collagenous amino-terminal and triple-helical domains.

Type X collagen, expressed by hypertrophic chondrocytes, consists of homotrimeric molecules with subunits that are only about one-half the size of the polypeptides of fibrillar collagens. In this report we describe for the first time the complete primary structure of type X collagen, based on cloning and sequencing of cDNA and genomic DNA. A comparison between the nucleotide sequences of the cDNA and genomic DNA clones has also allowed determination of the complete exon structure of the type X collagen gene. Our results demonstrate that the primary translation product of the chicken type X collagen mRNA is 682 amino acid residues long with a calculated molecular mass of 67,317 Da for the nonhydroxylated form. This calculated molecular mass is in excellent agreement with the observed electrophoretic mobility of cell-free translation products with both poly(A)+ RNA isolated from chondrocytes as well as RNA transcribed in vitro from a full length cDNA construct. It is also in agreement with the observed size of type X collagen polypeptides isolated from the media of cultured hypertrophic chondrocytes. Thus, our data exclude the possibility of a high molecular weight precursor form of type X collagen. Our results also confirm that the chicken type X gene has a most unusual exon structure when compared to other vertebrate collagen genes. The gene has only three exons. One exon (97 base pairs (bp)), codes for most of the 5'-untranslated region of the mRNA, a second exon (159 bp) codes for the signal peptide and a short non-triple-helical domain, while the third exon (2136 bp) contains the coding region for the entire triple-helix and a large non-triple-helical carboxyl domain.

Amino Acid Sequence↗
PubMed1988

Cloning and sequencing of pro-alpha 1 (XI) collagen cDNA demonstrates that type XI belongs to the fibrillar class of collagens and reveals that the expression of the gene is not restricted to cartilagenous tissue.

We have isolated several overlapping cDNA clones encoding alpha 1(XI) collagen chains from human and rat cDNA libraries. Together the human cDNAs code for 335 uninterrupted Gly-X-Y triplets, and a 264-amino acid C-propeptide, while the rat cDNAs cover the entire C-propeptide and about a third of the triple-helical domain. Comparison of the human and rodent nucleotide sequences showed a 95% sequence similarity. The identification of the clones as alpha 1(XI) cDNAs was based on the complete identity between the amino acid sequences of three human alpha 1(XI) cyanogen bromide peptides and the cDNA-derived sequence. Examination of and the cDNA-derived amino acid sequence showed a variety of structural features characteristic of fibrillar-forming collagens. In addition, nucleotide sequence analysis of a selected portion of the corresponding human gene revealed the characteristic 54-base pair exon motif. We conclude therefore that pro-alpha 1 (XI) collagen belongs to the group of fibrillar collagen genes. We also suggest that the expression of this gene is not restricted to cartilage, as previously thought, since the cDNA libraries from which the clones were isolated, originated from both cartilagenous and noncartilaginous tissues.

Amino Acid Sequence↗
PubMed1988

Amiloride inhibition of responses of rat single chorda tympani fibers to chemical and electrical tongue stimulations.

Amiloride inhibition of single fiber responses of the rat chorda tympani to ionic chemical and electrical tongue stimulations was studied. Amiloride reduced responses to both chemical and electrical stimulations with NaCl or LiCl in most of the single fibers. However, the magnitude of reduction of the response by amiloride varied among the fibers and was greater for chemical than electrical stimulation with NaCl in each fiber. Thirty-two single fibers were divided into two groups, such as 18 high (HAS) and 14 low amiloride-sensitive (LAS) fibers. Percent responses (control, 100%) of the former group to chemical stimulus with NaCl after amiloride ranged from 1.1 to 42.5%, while those of the latter from 72.8 to 108.0%. In HAS fibers, amiloride also reduced responses to KCl and CaCl2, but to a smaller degree than those to NaCl and LiCl. Fifteen out of 18 HAS fibers more strongly responded to a chemical stimulus with 0.1 M NaCl than 0.01 M HCl, while the opposite was true for 13 out of 14 LAS fibers, although the threshold concentration for NaCl was rather lower in LAS fibers than in HAS fibers. These results suggest that there exist at least two different receptor mechanisms for NaCl or LiCl which are amiloride-sensitive and -insensitive, and the observed differences in relative specificities to ionic taste stimuli and sensitivities to amiloride among rat chorda tympani fibers are possibly due to a disproportional distribution of these two receptors.

Amiloride↗
PubMed1988

Regulation of collagen metabolism and cell growth by epidermal growth factor and ascorbate in cultured human skin fibroblasts.

Epidermal growth factor (2-50 ng/ml), prepared from mouse submaxillary glands, stimulated growth and the synthesis of non-collagenous proteins and hyaluronic acid, but inhibited collagen synthesis in cultured human skin fibroblasts, both stimulation and inhibition being dose-dependent. All these effects may be intrinsic functions of the epidermal growth factor molecule, because these effects were cancelled by the co-presence of antiserum specific for epidermal growth factor and because they were also observed following the addition of human epidermal growth factor produced urogastrone cDNA. On the other hand, L-ascorbate (vitamin C) stimulated growth and collagen synthesis, as well as synthesis of non-collagenous proteins, with no significant effect on hyaluronic acid synthesis. Co-presence of epidermal growth factor and ascorbate gave additive effects on growth and protein synthesis of the cells. These results suggest that the two growth-promoting factors, epidermal growth factor and L-ascorbate, modulate metabolism of extracellular matrix components as well as cell growth in a quite different manner in human skin fibroblasts.

Adult↗
PubMed1988

Cartilage type IX collagen-proteoglycan contains a large amino-terminal globular domain encoded by multiple exons.

Type IX collagen in cartilage consists of molecules composed of three genetically distinct polypeptide subunits. One of the subunits, alpha 2(IX), contains a covalently attached glycosaminoglycan side chain whereas a second subunit, alpha 1(IX), contains a large noncollagenous, amino-terminal domain called NC4. In this report, we describe for the first time the complete primary structure of this noncollagenous domain, based on cloning and sequencing of cDNA and genomic DNA as well as amino acid sequencing of tryptic peptides. Analysis of genomic clones has also allowed determination of the exon structure of NC4. Our results demonstrate that the noncollagenous, amino-terminal domain of alpha 1(IX) chains contains 266 amino acid residues (including the signal peptide) with 5 cysteinyl residues forming two disulfide bridges. The domain is basic with an estimated pI of 9.7, thus supporting the idea that it may participate in ionic interactions with polyanionic glycosaminoglycans in cartilage. Both the sequence and exon structure of the NC4 domain is unique among collagens and there is no obvious homology with the noncollagenous domains of other types of collagen, including the propeptides of fibrillar collagens.

Amino Acid Sequence↗
PubMed1988

Embryonic chicken cornea and cartilage synthesize type IX collagen molecules with different amino-terminal domains.

We have analyzed embryonic chicken cornea for the presence of type IX collagen mRNA and protein. Using RNA transfer blot analysis, we demonstrate that alpha 1(IX) and alpha 2(IX) mRNAs are expressed by corneal epithelial cells at the time that the primary stromal components are synthesized. The levels of the mRNAs decrease with increasing developmental age and are barely detectable at day 11 of development. In contrast, type IX collagen protein is detectable by immunofluorescence at days 5 and 6 and undetectable by day 8. Using probes specific for alpha 1(IX) and alpha 2(IX) mRNAs, we demonstrate that the size of alpha 2(IX) mRNA is the same in cornea as in chondrocytes, the major source of type IX collagen. However, the alpha 1(IX) mRNA is about 700 nucleotides shorter in the cornea than in cartilage because the corneal form of the mRNA does not contain the 5' region that encodes the non-triple-helical amino-terminal globular domain of cartilage type IX collagen. Therefore, corneal type IX collagen must lack this domain. This structural modulation of an extracellular matrix protein is likely to contribute to the functional differences between cartilage matrix and the early corneal stroma, both of which are rich in type II collagen.

Amino Acid Sequence↗
PubMed1988

Secretion of collagen types I and II by epithelial and endothelial cells in the developing chick cornea demonstrated by in situ hybridization and immunohistochemistry.

Cells involved in the synthesis of collagen types I and II in the cornea of developing chick embryos have been studied by using in situ hybridization and immunohistochemistry. Corneas processed for in situ hybridization with the type I and II collagen probes demonstrated specific mRNAs in the epithelium of embryos at stage 18 with an increase at stages between 26 and 31, and then gradual decrease to the background level in the next several days. In the endothelium, a small amount of specific mRNA was recognized through these stages. In the stroma, only sections hybridized with the type I probe demonstrated mRNA in fibroblasts. Immunostaining demonstrated specific collagen types in the stroma at sites which were closely associated with cells containing specific mRNAs. Both collagens type I and II were present beneath the epithelium as narrow bands at stage 18; as the thicker primary stroma at stages 20 and 26; and as subepithelial, subendothelial and stromal staining at stage 31. Thereafter, type I collagen was increased in the stroma but it was also noted in the subepithelial and, to a lesser degree, subendothelial regions, whereas type II collagen was gradually confined to the subendothelial matrix. Electron microscopic examination of sections from 5-day-old (stage-27) embryo corneas using antibodies against the carboxyl propeptides of type I and II procollagens revealed the presence of these procollagens within the cisternae of the endoplasmic reticulum and Golgi vesicles in both epithelial and endothelial cells. In the epithelial cells both the periderm and basal cells contained these procollagens within the cytoplasmic organelles. These results indicate that not only the epithelial cells, but also the endothelial cells secrete collagen types I and II during the formation of the primary corneal stroma and for several days after invasion of fibroblasts.

Animals↗
PubMed1988

[Antitumor activity and toxicity to the immune system and intestine, of the fluorinated pyrimidines FUra, 5'-DFUR, tegafur and UFT].

Antitumor activity and the toxicities of 5-fluorouracil (FUra) and its depot form derivatives with different mechanisms such as 5'-DFUR, tegafur and UFT, were compared in mice, and the therapeutic indices were measured. 5'-DFUR was less toxic to immune organs and the functions than those by other fluorinated pyrimidines. The therapeutic indices of 5'-DFUR obtained by using parameters of particular side effects, reduction of the number of GM-CFU in the bone marrow, shrinkage of the thymus, functional disorders in the immune systems, were several times higher than those of tegafur and UFT. On the other hand, there were no marked differences in the intestinal toxicities among the compounds. 5'-DFUR was only about two times less toxic on the intestinal tract than tegafur and UFT when the incidence-of diarrhea and damage to the duodenum were compared. These studies suggest that the difference in the mechanisms converting to FUra is a result of the toxicities causing different extent.

Animals↗
PubMed1988

[A case report of advanced ovarian cancer with chronic renal dysfunction treated by CDDP i.p].

Reported in this paper is a case of a 56-year-old female patient who was diagnosed as having an ovarian cancer (stage T 4) with a renal dysfunction (CCr 30.5 ml/min). We instilled CDDP intra-peritoneally (CDDP-ip), taking into consideration the peritoneal clearance (CLp.). The administration of sodium thiosulphate also was combined. The low CLp. of this case (299.2 ml/h) made it possible to instill a high dose in the peritoneal cavity and a low dose in the plasma. This method provided enough of anti-tumor effect and kept the renal function safe. We believe that the CLp. is the most important factor in determining the effect and side effects of CDDp-ip.

Cisplatin↗
PubMed1987

Serum angiotensin converting enzyme activity in ex-smokers.

A low activity of angiotensin converting enzyme (ACE) has been reported in people who smoke. To determine whether this low ACE activity would be reversible on cessation of smoking, we measured serum ACE activity in 107 healthy male volunteers. They included 27 active cigarette smokers, 28 non-smokers, 24 ex-smokers who had stopped smoking for less than 10 yr, and 28 ex-smokers who had stopped smoking for more than 10 yr. The mean value (+/-SD) of serum ACE in those who had stopped smoking for more than 10 yr was comparable to that of non-smokers: 23.2 +/- 5.1 and 23.5 +/- 4.5, respectively. ACE activity in smokers and the ex-smokers who had stopped smoking for less than 10 yr was significantly lower (17.8 +/- 4.5 and 17.8 +/- 3.9, respectively) than values obtained in non-smokers and the group who had not smoked for more than 10 yr (p less than 0.001). These findings suggest that the effect of chronic smoking on the serum ACE activity may be reversible.

Aged↗