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Biomedical subjects

Y Akai

Publications and source records attributed to Y Akai.

At least 37 records · Page 2Linked to original sources
PubMed1996

Quantification of glomerular TGF-beta 1 mRNA in patients with diabetes mellitus.

Transforming growth factor-beta 1 (TGF-beta 1) is a primary determinant of the mesangial expansion observed in diabetic nephropathy. In this study, we quantitated the levels of intraglomerular TGF-beta 1 mRNA in patients with diabetes mellitus using a competitive polymerase chain reaction (PCR) method. Renal biopsy specimens were obtained from 29 patients with non-insulin-dependent diabetes mellitus. Total RNA was extracted from the glomeruli and reverse transcribed into cDNA with reverse transcriptase. To prepare samples containing identical amounts of beta-actin cDNA (8 pg), we performed competitive PCR by co-amplifying mutant templates of beta-actin with a unique EcoRI site. We also used this competitive PCR method to measure TGF-beta 1 cDNA by co-amplifying mutant templates of TGF-beta 1. We observed higher expression of TGF-beta 1 mRNA in glomeruli of patients with diabetic nephropathy as compared with normal glomeruli. Intraglomerular TGF-beta 1 mRNA was elevated, even in the early stage of diabetic nephropathy. Moreover, levels of intraglomerular TGF-beta 1 mRNA correlated with values of HbA1c. These data suggest that hyperglycemia induces intraglomerular TGF-beta 1 mRNA expression in vivo, and that TGF-beta 1 overproduction may be associated with the progression of diabetic nephropathy.

Aged↗
PubMed1996

IL-6 mRNA synthesis by peripheral blood mononuclear cells (PBMC) in patients with chronic renal failure.

We measured levels of IL-6 mRNA in PBMC obtained from patients with chronic renal failure, using polymerase chain reaction (PCR). PBMC were isolated from 45 patients on haemodialysis (HD) at the start of HD. PBMC were also isolated from 35 patients on HD at the end of HD, 23 patients on continuous ambulatory peritoneal dialysis (CAPD), 24 undialysed patients with chronic renal failure (CRF), and 19 healthy controls. Total RNA was extracted from PBMC with RNA zol and reverse transcribed into cDNA. To prepare samples containing identical amounts of beta-actin cDNA, we performed competitive PCR by co-amplifying serial dilutions of mutant templates containing a single point mutation which generated a unique Eco RI site. Next, to measure IL-6 cDNA semiquantitatively in the samples containing identical amounts of beta-actin (100 pg), we performed PCR amplification using 2 fg of the IL-6 mutant template containing a unique Eco RI site. Higher levels of IL-6 mRNA in the PBMC were observed in the HD patients than in the CAPD patients and healthy controls. The levels of IL-6 mRNA in the PBMC at the end of HD were not significantly higher than those at the start of HD. These results suggest that the dialysis session itself did not significantly affect IL-6 mRNA levels in the PBMC, but that chronic stimulation by maintenance HD may be associated with higher levels of IL-6 mRNA observed in HD patients.

Adult↗
PubMed1996

PMA and ionomycin differently affect atrial natriuretic peptide stimulated cyclic GMP production in rat mesangial cells.

How 4 beta-phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io), a calcium ionophore, affect on the atrial natriuretic peptide (ANP) stimulated cyclic-3',5'-guanosine monophosphate (cGMP) production in cultured rat mesangial cells was examined. Cultured mesangial cells were prepared by isolated glomeruli from Sprague Dawley rats employing the sieving method and were used between the 3rd and 15th passage for experiments. cGMP and protein contents were measured by radioimmunoassay and Lowry method. Incubations with effectors were carried out either in the presence or absence of 0.5 mM 1-methyl-3-isobutyl-xanthine (MIX). The intracellular concentration of calcium ([Ca2+]i) was determined by using the Fura-2 method. Pretreatment with PMA, an activator of protein kinase C (PKC), attenuated ANP stimulated cGMP production in a time- and dose-dependent fashion, while alpha PDD (an inactive analog of PMA) did not inhibit cGMP production. PMA inhibition was reversed by addition of staurosporine, a protein kinase C inhibitor. Io attenuated ANP stimulated cGMP production in the absence but not in the presence of MIX. These findings suggested that PMA acts on ANP receptor or guanylate cyclase via activation of PKC in rat mesangial cells. Io may inhibit ANP stimulated cGMP production via activation of cyclic nucleotide phosphodiesterase.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Automated nurse rostering system for administrative efficiency as a subsystem of a total hospital information system.

After trying a variety of nurse scheduling packages, the Chiba University Hospital chose to develop their own system and implemented it in April 1994. The system is the newest component of their HIS which has been functioning since 1991. The rostering system avails itself of the modern client server technology which has been installed over the past few years.

Hospital Information Systems↗
PubMed1994

Intraglomerular expressions of IL-1 alpha and platelet-derived growth factor (PDGF-B) mRNA in experimental immune complex-mediated glomerulonephritis.

Both PDGF and IL-1 play important roles as autocrine growth factors for cultured mesangial cells, and may be closely associated with the progression of glomerulonephritis. In this study we investigated intraglomerular expressions of PDGF-B and IL-1 alpha mRNA in mice with bovine serum albumin (BSA) nephritis, a model of immune complex-mediated glomerulonephritis, using the reverse transcription-polymerase chain reaction (RT-PCR) method. We also quantified intraglomerular PDGF-B mRNA by the competitive PCR and studied the correlation between the level of intraglomerular PDGF-B mRNA expression and the degree of observed glomerular injury. While expression of neither PDGF-B nor IL-1 alpha mRNA was detected in glomeruli from control mice, both were strongly expressed in glomeruli from mice with BSA nephritis. IL-1 alpha mRNA in glomeruli showed low accumulation in mice with mild glomerular injury, and was increased in mice with moderate glomerular injury. In contrast, high intraglomerular expression of PDGF-B mRNA occurred in all mice with mild glomerular injury and continued throughout the course of the disease. We observed no correlation between the level of PDGF-B mRNA expression and the histologic grade of renal damage. These results suggest that PDGF and IL-1 have different growth properties, and PDGF might play a role as a competence factor rather than a progression factor in the pathogenesis of immune complex-mediated glomerulonephritis.

Animals↗
PubMed1994

Intraglomerular expression of transforming growth factor-beta 1 (TGF-beta 1) mRNA in patients with glomerulonephritis: quantitative analysis by competitive polymerase chain reaction.

TGF-beta 1 is involved in the pathogenesis of glomerular sclerosis. We studied the intraglomerular expression of TGF-beta 1 mRNA in patients with glomerulonephritis using competitive polymerase chain reaction (PCR). This method is sensitive enough to quantify cDNA copies of mRNA present in small amounts of samples. Renal biopsy specimens were obtained from 42 patients with various kinds of glomerulonephritis. Ten glomeruli were dissected from renal biopsy specimens. Normal glomeruli were also obtained from the resected kidneys of eight patients with renal cell cancer. Total RNA was extracted from the glomeruli and reverse transcribed into cDNA with reverse transcriptase. To prepare samples containing identical amounts of beta-actin cDNA (8 pg), we performed competitive PCR by co-amplifying mutant templates of beta-actin with a unique EcoRI site. Next, to measure TGF-beta 1 cDNA, we performed competitive PCR by co-amplifying mutant templates of TGF-beta 1. We observed a higher glomerular expression of TGF-beta 1 mRNA in cases of mesangial proliferative glomerulonephritis having a moderate increase in mesangial matrix, diabetic nephropathy and diffuse proliferative lupus nephritis, compared with normal glomeruli. Results suggest that the intraglomerular synthesis of TGF-beta 1 may be involved in the progression of glomerulonephritis in humans.

Actins↗
PubMed1994

Mechanical stretch/relaxation of cultured rat mesangial cells induces protooncogenes and cyclooxygenase.

In cultured rat glomerular mesangial cells, continuous cycles of stretching and relaxation (stretch/relaxation) stimulate cell proliferation, protein synthesis, and prostaglandin production. We examined regulation of gene expression that may underlie these alterations in cell functions. Stretch/relaxation caused time-dependent induction of the immediate early genes, c-fos and zif 268/egr-1, with maximal increases occurring between 15 and 30 min. The mitogen-inducible prostaglandin G2/H2 synthase (PGH2S-2) gene was also induced within 30 min of stretch/relaxation, with concomitant increases in the immunoreactive PGH2S-2 protein. These gene inductions were preceded by transient translocation of protein kinase C activity from cytosol to membrane as well as by increases in 45Ca2+ uptake and total cellular calcium content. The stretch/relaxation-induced expression was suppressed by protein kinase C inhibition, whereas less profound inhibition was observed with inhibition of calcium influx in low (100 nM) calcium buffer. These findings indicate that in mesangial cells mechanical stress induces expression of the protooncogenes and the mitogen-inducible cyclooxygenase primarily through protein kinase C-dependent mechanisms.

Animals↗
PubMed1994

Cyclooxygenase-2 is associated with the macula densa of rat kidney and increases with salt restriction.

The kidney is a rich source of prostaglandins. These eicosanoids, formed by cyclooxygenase-dependent metabolism of arachidonic acid, are important physiologic mediators of renal glomerular hemodynamics and tubular sodium and water reabsorption. Two separate isoforms of cyclooxygenase (COX) have now been identified: constitutive COX-1, encoded by a 2.8-kb mRNA, and mitogen-activated COX-2, encoded by a 4.0-4.5-kb mRNA. COX-2 expression increases during development and inflammation, but, except for brain, constitutive expression is low. It has been generally accepted that physiologic renal production of prostaglandins is mediated by COX-1. However, in the absence of inflammation, low levels of COX-2 mRNA are also detectable in the kidney. To examine the role of COX-2 in the kidney and determine its intrarenal localization, we used a 1.3-kb cDNA probe specific for the 3' untranslated region of rat COX-2 and COX-2-specific antiserum. The COX-2-specific cDNA probe hybridized with a 4.4-kb transcript in total RNA from adult rat kidney. Immunoblots of microsomes isolated from kidney cortex and papilla indicated immunoreactive COX-2 in both locations. In situ hybridization and immunohistochemistry indicated that renal cortical COX-2 expression was localized to the macula densa of the juxtaglomerular apparatus and to adjacent epithelial cells of the cortical thick ascending limb of Henle. In addition, COX-2 immunoreactivity was detected in interstitial cells in the papilla. No COX-2 message or immunoreactive protein was detected in arterioles, glomeruli, or cortical or medullary collecting ducts. When animals were chronically sodium restricted, the level of COX-2 in the region of the macula densa increased threefold (from 0.86 +/- 0.08 to 2.52 +/- 0.43/mm2) and the total area of the COX-2 immunoreactive cells in cortex increased from 34 microns2/mm2 of cortex to 226 microns2/mm2 of cortex. The intrarenal distribution of COX-2 and its increased expression in response to sodium restriction suggest that in addition to its proposed role in inflammatory and growth responses, this enzyme may play an important role in the regulation of salt, volume, and blood pressure homeostasis.

Animals↗
PubMed1993

A case of a female infant with simultaneous occurrence of de novo terminal deletions on chromosome 14q and 20p.

This is a case report on an infant with de novo terminal deletions on the long arm of chromosome 14 and on the short arm of chromosome 20 [46, XX, del(14)(q32)del(20)(p11)]. Examination revealed that the infant had a peculiar face, a cleft and high palate, abnormal dentition, butterfly-like vertebral defects, finger anomalies, a simian line on the left hand, talipes equinovarus, deep plantar furrows, abnormally high values of alkali phosphatase and lactate dehydrogenase, mild anemia and psychomotor retardation. Comparing the present case with previously reported cases of a single deletion on chromosome 14q or chromosome 20p, the infant showed some symptomatic and dysmorphic features of both deletions.

Abnormalities, Multiple↗
PubMed1992

Activation of S6 kinase by repeated cycles of stretching and relaxation in rat glomerular mesangial cells. Evidence for involvement of protein kinase C.

Quiescent rat glomerular mesangial cells were exposed to repeated cycles of stretching and relaxation, and the effects on the rate of collagen production, proliferation, and S6 kinase activity were investigated. Stretch/relaxation induced increases in production of both collagen and non-collagenous proteins. Proliferation of mesangial cells was stimulated by stretch/relaxation and epidermal growth factor, but not by angiotensin II; however, administration of angiotensin II augmented stretch/relaxation-induced cell proliferation. Cytosolic S6 kinase activity was stimulated by stretch/relaxation, angiotensin II, epidermal growth factor, or phorbol 12-myristate 13-acetate. The increased S6 kinase activity was detectable within 30 min after initiation of stretch/relaxation and was blocked by either inhibitors of protein kinase C or prior down-regulation of protein kinase C following prolonged incubation with phorbol 12-myristate 13-acetate. Both translocation of protein kinase C from the cytosolic to the membrane fraction and phosphorylation of an endogenous 80-kDa protein were observed within 5 min of initiation of stretch/relaxation. These results demonstrate that in mesangial cells, mechanical factors alone can induce increases in production of collagen and non-collagenous proteins and in cell proliferation. The observation that stretch/relaxation induced stimulation of S6 kinase activity through protein kinase C-dependent mechanisms suggests that activation of protein kinase C may be a key event in initiating adaptive responses of mesangial cells to increased workload.

Adenosine Triphosphate↗
PubMed1992

Separation of diffusion and slow flow effects by use of flow rephasing and dephasing.

Spin-echo signal intensity alterations due to diffusion and slow flow are investigated in connection with modified Stejskal-Tanner pulse sequences for 2D Fourier MR imaging, one for flow rephasing and the other for flow dephasing gradient waveforms. The theoretical considerations and experimental results concerning the diffusion coefficient measurements of slowly flowing material by these sequences are summarized as follows: (a) By using the flow dephasing sequence with different diffusion and flow-sensitive gradients, slow flow effects can be distinguished from diffusion effects based on the quantitative difference between the diffusion- and flow-sensitive gradient amplitude dependences of these processes. (b) By using the combination of the flow rephasing and dephasing sequences with the same diffusion sensitivity, slow flow effects can be distinguished from diffusion effects directly based on their qualitative difference. By use of the latter approach, several in vivo images are also presented, which mainly represent macroscopic motions of spins, including slow flow such as tissue perfusion.

Acetone↗
PubMed1992

Pericentric inversion of chromosome 9 in prenatal diagnosis and infertility.

In order to evaluate the relation between pericentric inversion of chromosome 9 (inv(9)) and clinical problems, the characteristics of inv(9) were investigated on the basis of chromosomal analyses of fetuses and infertile couples. The incidence of such inversion in fetuses with parents having an offspring who suffered from various clinical problems was significantly higher than the basic incidence obtained in fetuses karyotyped by reason of advanced maternal age. In the chromosomal examination of the parents whose fetuses were diagnosed as inv(9), it was revealed that either parent might be the carrier. Furthermore, in the inv(9) carrying fetuses, the number of females was significantly greater than that of males. Analysis of infertile couples revealed that the incidence of such inversion in males was significantly higher than the basic incidence mentioned above. Moreover, infertile couples with an inv(9) carrier showed a significantly higher incidence of intrauterine fetal death, compared with infertile couples with a translocation carrier or those in which the etiology was unknown. These results indicate that inv(9) may often cause clinical problems in offspring of the carrier and infertility with unknown mechanisms related to sex.

Chromosome Aberrations↗
PubMed1992

[Glomerulopathy associated with glomerular microtubular deposits: a report of a case].

A male aged 58 was admitted to our hospital because of proteinuria, hematuria and bilateral pretibial edema. Laboratory tests showed normocytic, normochromic anemia and moderately impaired renal function. Antinuclear antibodies were negative. Neither M-protein nor Bence-Jones protein were detected. Light microscopic study on the biopsied renal specimen indicated a moderate mesangial proliferation accompanying with the deposition of PAS-positive and Congo red-negative materials in the subendothelial area. C3 accumulated segmentally along the capillary walls, which was clarified by immunofluorescence microscopy. Staining for IgG, IgA, IgM and light chains were negative. Electron microscopy demonstrated the deposition of microtubules in the mesangial, subepithelial and subendothelial areas. The diameter of these microtubules ranged from 40 to 80 nm. Such type of the microtubules have been reported to exist in the glomeruli in the patients with systemic diseases such as amyloidosis, systemic lupus erythematosus, cryoglobulinemia and light chain disease. In our patient, however, any clinical or serological findings suggestive of these systemic diseases were not obtained. On the other hand previous report pointed out that microtubules deposited in the glomeruli in the patients with immunotactoid glomerulopathy or other glomerulopathies. Our patient had the clinical features consistent with these glomerulopathies. However, no depositions of immunoglobulins were observed. This case is an atypical glomerulopathy accompanying with the glomerular microtubular deposits.

Complement C3↗
PubMed1991

Application of plasma perfusion in hepatic failure.

To evaluate the efficacy of plasma perfusion as a liver-assistance system, 17 patients with hepatic failure were treated with a total 37 sessions of plasma perfusion and 43 sessions of plasma exchange. For plasma perfusion, Plasma-flo AP-08-H was used as a plasma separator, and the separated plasma was passed through an adsorber, Bespore UPC-III (Jap.Med.Suppl., Hiroshima) or BR 350 (Asahi Med. Co., Tokyo). The mean treated plasma volume was 5.0 liters. The mean proportion of bilirubin removed by routine plasma exchange was 29% with a mean of plasma exchange volume of 2.1 L. In the plasma perfusion with Bespore and BR, the removal rates were 37% and 42%, respectively. The plasma ammonia level decreased by 16% (from 121 to 97 mumol/L) with plasma exchange. Likewise, plasma perfusion decreased the plasma ammonia level from 75 to 56 mumol/L with an average decrement rate of 23%. The capacity for removal of amino acids was analyzed in terms of the change in the Fisher score ([Val+Leu+Ileu]/[Tyr+Phe]). The Fisher score was improved by plasma perfusion from 1.8 to 2.4. Thus, we concluded that in terms of removal of bilirubin, ammonia and amino acids, plasma perfusion was as efficient a therapy as plasma exchange. However, further clinical evaluation will be required before this procedure can be applied for the treatment of hepatic failure.

Adult↗
PubMed1990

Effects of velocity profile of to-and-fro pulsatile flow on magnetic resonance signal intensity.

The effects of to-and-fro pulsatile flow, i.e., an oscillatory fluid motion with no net flow, on signal intensity in gated spin-echo magnetic resonance imaging are considered both theoretically and experimentally. On the basis of hydrodynamic principles, to-and-fro pulsatile flow at large Womersley numbers consists of uniform inner flow and boundary-layer-type flow adjacent to a tube wall. Therefore, the velocity profile is "trapezoidal" rather than parabolic at all times during the pulsation period. Contrary to the absence of phase dispersion and loss of signal within the inner flow where no velocity gradient exists, large velocity differences cause phase dispersion and, hence, loss of signal within the boundary layer, whose thickness is inversely proportional to the Womersley number. An understanding of these features of to-and-fro pulsatile flow provides the theoretical basis of cerebrospinal fluid flow phenomena in magnetic resonance imaging, since this type of flow exists in cerebrospinal fluid pathways.

Cerebrospinal Fluid↗