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Biomedical subjects

Y Terada

Publications and source records attributed to Y Terada.

At least 19 recordsLinked to original sources
PubMed1992

Availability of the in situ right gastroepiploic artery for coronary artery bypass.

The right gastroepiploic artery (GEA) has been successfully used as a coronary bypass graft recently. We examined the in situ GEA graft length required from the pyloric portion to the site of coronary anastomosis at the time of operation. Measured GEA length was 17.0 +/- 1.7 cm for the posterior descending artery anastomosis in 17 patients, 17.8 +/- 1.7 cm for the main right coronary artery anastomosis in 13 patients, 22.0 +/- 2.3 cm for the posterolateral branch anastomosis in 7 patients, and 21.0 cm for the left anterior descending artery anastomosis in 1 patient. We examined 228 randomly selected abdominal angiograms and measured the internal diameter of the right GEA at every 2-cm interval from its origin. Probability of availability of the in situ GEA graft for each site of anastomosis was 97% to the right coronary artery and 88% to the anterior descending or the circumflex artery when the internal diameter of GEA was 1.5 mm or greater. From an anatomical standpoint, we concluded that the GEA can be assumed available without preoperative angiography.

Adult↗
PubMed1992

Renal effects of alacepril in essential hypertension.

Short-term effects of alacepril, an angiotensin-converting enzyme inhibitor (ACEI), on renal function and hemodynamics were investigated in 10 hypertensive subjects (aged 55.7 +/- 9.5 years, mean +/- SD). Renal plasma flow (RPF) and glomerular filtration rate (GFR) were examined before and after 12-week administration of alacepril, by [131I]hippuran and [99mTc]DTPA, respectively. Alacepril (50 mg/day) caused a significant decrease in both systolic and diastolic blood pressure (SBP and DBP, from 161 +/- 8 to 140 +/- 10 mm Hg and from 100 +/- 3 to 90 +/- 5 mm Hg, respectively). Alacepril increased GFR (from 63.4 +/- 22.2 to 69.1 +/- 22.1 ml/min/1.73 m2, p less than 0.05) without changing RPF (from 438 +/- 194 to 432 +/- 148 ml/min/1.73 m2, p greater than 0.05). Serum creatinine and electrolytes were not changed by alacepril administration. These data show that short-term alacepril administration improves renal function, probably owing to relaxation of renal vasoconstriction.

Adult↗
PubMed1992

Hormone and autacoid regulation of cAMP production in rat IMCD subsegments.

The inner medullary collecting duct (IMCD) of the rat consists of two structurally and functionally distinct segments, i.e., the initial and the terminal IMCD. To identify factors that may regulate the transport function in the IMCD segments, we assessed whether catecholamines, carbachol, prostaglandin E2 (PGE2), bradykinin, glucagon, calcitonin, parathyroid hormone, or epidermal growth factor affects adenosine 3',5'-cyclic monophosphate (cAMP) production in microdissected tubules in the presence and absence of arginine vasopressin (AVP, 0.1 nM). All experiments were performed in the presence of 3-isobutyl-1-methylxanthine, and cAMP was measured by radioimmunoassay. Epinephrine (greater than or equal to 50 nM) and clonidine (greater than or equal to 1 microM) markedly decreased AVP-induced cAMP levels in both IMCD segments. However, phenylephrine did not show an effect. The inhibitory effect of epinephrine was blocked by yohimbine (50 nM) but not by prazosin (50 nM). In isolated perfused terminal IMCDs, epinephrine inhibited AVP-stimulated urea permeability. Isoproterenol (1 microM), in the absence of AVP, caused a significant increase in cAMP level only in the initial IMCD. Propranolol (1 microM) inhibited this isoproterenol effect, but atenolol did not. Dopamine (less than or equal to 1 microM) had no effect on cAMP levels in either IMCD segment. Carbachol, PGE2, and the various peptide hormones had no effect on cAMP levels (+/- AVP) in either IMCD segment. We conclude that an adrenergic beta 2-receptor is present only in the initial IMCD, where its occupation increases cAMP production. We conclude also that an adrenergic alpha 2-receptor is present in both IMCD segments, where its occupation inhibits AVP-induced cAMP production.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Age-related changes in alpha 1- and alpha 2-chain type IV collagen mRNAs in adult mouse glomeruli: competitive PCR.

Studies of age-related changes in glomerular extracellular matrix (ECM) synthesis in normal mice have been hampered by the difficulty of isolating sufficient numbers of intact glomeruli and by the inability to quantify different mRNA species. The purpose of this study was to identify and quantitate the individual mRNAs coding for alpha 1- and alpha 2-chains of type IV collagen in isolated, single glomeruli of normal mice at different ages. These data on normal ECM synthesis were necessary for the understanding of glomerulosclerosis, a condition characterized by excess deposition of collagen. Pools of freshly microdissected adult mouse glomeruli were reverse transcribed in situ, and alpha 1-IV and alpha 2-IV collagen mRNAs were individually amplified by means of specific primers and the polymerase chain reaction (PCR), according to a previously published method. A competitive PCR assay, based on utilization of mutated cDNAs, allowed the reproducible, quantitative, and separate determination of the absolute amounts of both alpha 1-IV and alpha 2-IV mRNAs measured, as their respective cDNAs, in one-tenth of one glomerulus. The levels of alpha 1-IV and alpha 2-IV collagen mRNA were 208 +/- 36.0 x 10(-4) and 161.2 +/- 18.6 x 10(-4) amol/glomerulus in 5-wk-old mice. There were no significant age-related differences at 8, 12, and 24 wk. The mean levels over this period were 60.2 +/- 4.9 x 10(-4) for alpha 1-IV collagen mRNA and 63.9 +/- 5.8 x 10(-4) amol/glomerulus for alpha 2-IV collagen mRNA. Two of three 24-wk-old mice had mild glomerulosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Different localization of two types of endothelin receptor mRNA in microdissected rat nephron segments using reverse transcription and polymerase chain reaction assay.

Recent studies have revealed that endothelins (ETs) have at least two types of receptors. One receptor has high affinity to ET-1 and ET-2 and low affinity to ET-3 (A type). The other receptor binds almost equally to ET-1, ET-2, and ET-3 (B type). In this study, microlocalization of mRNA coding for the A-type and B-type ET receptors was carried out in the rat kidney using a reverse transcription and polymerase chain reaction assay of individual microdissected renal tubule segments along the nephron, glomeruli, vasa recta bundle, and arcuate arteries. Large signals for the B-type receptor polymerase chain reaction product were detected in the initial and terminal inner medullary collecting duct and the glomerulus, while small signals were found in the cortical collecting duct and outer medullary collecting duct, vasa recta bundle, and arcuate artery. In contrast, A-type receptor mRNA was detected only in the glomerulus, vasa recta bundle, and arcuate artery. Thus, the two ET receptor subtypes are distributed differently along the nephron. This suggests that the two types of receptors and ET families may affect kidney functioning in different ways.

Animals↗
PubMed1992

Polymerase chain reaction localization of constitutive nitric oxide synthase and soluble guanylate cyclase messenger RNAs in microdissected rat nephron segments.

Stimulation of the release of nitric oxide (NO) in the kidney has been shown to result in renal hemodynamic changes and natriuresis. NO is a potent stimulator of soluble guanylate cyclase, leading to an increase of cyclic GMP. The precise localization of NO synthase and soluble guanylate cyclase in the renal structure is not known. In this study, the microlocalization of mRNAs coding for constitutive NO synthase and soluble guanylate cyclase was carried out in the rat kidney, using an assay of reverse transcription and polymerase chain reaction in individual microdissected renal tubule segments along the nephron, glomeruli, vasa recta bundle, and arcuate arteries. A large signal for constitutive NO synthase was detected in inner medullary collecting duct. Small signals were detected in inner medullary thin limb, cortical collecting duct, outer medullary collecting duct, glomerulus, vasa recta, and arcuate artery. Soluble guanylate cyclase mRNA is expressed largely in glomerulus, proximal convoluted tubule, proximal straight tubule, and cortical collecting duct, and in small amounts in medullary thick ascending limb, inner medullary thin limb, outer medullary collecting duct, inner medullary collecting duct, and the vascular system. Our data demonstrate that NO can be produced locally in the kidney, and that soluble guanylate cyclase is widely distributed in glomerulus, renal tubules, and the vascular system.

Amino Acid Oxidoreductases↗
PubMed1992

Messenger RNA expression and synthesis of endothelin-1 along rat nephron segments.

The kidney both produces and responds to endothelin. We examined the production and the expression of mRNA of endothelin-1 (ET-1) in tubule suspensions and microdissected nephron segments. ET-1 production was measured by RIA using an ET-1-specific antibody. We applied the reverse transcription and polymerase chain reaction (PCR) technique to detect ET-1 mRNA along the nephron segments. Stimulation of ET-1 production was observed in the presence of FCS and transforming growth factor-beta (TGF-beta) in inner medullary tubules but not in cortical or outer medullary tubule suspensions. Among dissected nephron segments, ET-1 production was observed in glomeruli and inner medullary collecting ducts (IMCD), whereas it was negligible in proximal convoluted tubules (PCT) and medullary thick ascending limbs (MAL). In addition, the PCR product of ET-1 mRNA was also higher in glomeruli and IMCD, whereas it was undetectable in PCT and MAL. Furthermore, FCS and TGF-beta increased ET-1 mRNA in microdissected glomeruli and IMCD. These data clearly demonstrated that the production sites of ET-1 are glomeruli and IMCD among the nephron segments. ET-1 is an autocrine factor in these sites.

Animals↗
PubMed1992

Plasma high density lipoprotein in anemic cattle infected with Theileria sergenti.

Changes in plasma concentration of lipid composition were analysed in cattle with anemia due to Theileria sergenti infection. Plasma levels of phospholipids, cholesterol, free cholesterol, high density lipoprotein cholesterol, and vitamin E decreased to 40-67% of the pre-infection levels, corresponding to the decrease of PCV due to the infection. However, no definite changes were detected in plasma level of triglyceride. By gradient centrifugation, it was confirmed that lipid components, other than triglyceride, occur in high density lipoprotein (HDL) and these decreases lowered the HDL value. There was no correlation between this phenomenon and liver function. As similar changes in lipid composition were also observed in phlebotomized calves, it was considered that this phenomenon might partially depend on the acceleration of erythropoiesis as a reaction to anemia caused by T. sergenti infection.

Anemia↗
PubMed1992

The effects of cromolyn sodium in dogs undergoing high-frequency oscillation superimposed on conventional mechanical ventilation.

The effects on gas exchange of superimposition of high-frequency oscillation (HFO) (40 Hz) on conventional mechanical ventilation were investigated in mongrel dogs with eucapnic gas exchange on conventional mechanical ventilation (CMV). The dogs were anesthetized, paralyzed, and ventilated with CMV until stable. Oscillation was then superimposed for 15 min, followed by CMV alone for a further 30 min. During HFO superimposed on CMV (CMV-HFO), the arterial carbon dioxide tension (PaCO2) increased from 43.6 +/- 1.2 mm Hg to 47.2 +/- 1.4 mm Hg (p less than 0.02), whereas the arterial oxygen tension (PaO2) did not change at all. The change was inhibited completely by administration of intravenous cromolyn sodium (CS) (6 mg/kg/min). The mean pulmonary arterial pressure (mPAP), cardiac output (CO), pulmonary capillary wedge pressure (PCWP), and pulmonary vascular resistance (PVR) did not change during the experiment. These results demonstrate that CMV-HFO appears to cause CO2 accumulation and eliminates the impaired O2 transfer, and that these effects are inhibited completely by CS administration.

Animals↗
PubMed1992

[Endothelin, EDRF, CGRP].

Endothelin-1 is now known to synthesized in the kidney and influence the renal function. ET-1 mRNA was detected in glomerulus and inner medullary collecting ducts using RT-PCR technique. ETA receptor mRNA was detected only in glomerulus, vasa recta bundle, and arcuate artery. ETB receptor mRNA distributed mainly in glomerulus and collecting ducts. Endothelium derived relaxing factor (EDRF) was believed to be nitric oxide, was synthesized by nitric oxide (NO) synthase from L-arginine. NO stimulates soluble guanylate cyclase and increases cGMP level. NO synthase mRNA was detected in glomerulus and inner medulla. Soluble guanylate cyclase mRNA distributed widely along the nephron segments. NO and cGMP system seems to play some roles in modulating renal functions.

Amino Acid Oxidoreductases↗
PubMed1992

[The calcified ascending aorta--preoperative evaluation and intraoperative management].

Aortic calcification was evaluated preoperatively by computed tomography (CT) in 136 of 275 candidates for coronary artery bypass surgery (age range, 30-80) years (mean 60.2 years), including 110 men and 26 women), from April 1989 to March 1991. Calcification in the mid-ascending aortic wall was detected in 20 (14.7%) cases, calcification in all regions of the aorta was more common in patients older than 60 years (22.5%, n = 71), than younger (6.2%, n = 65) (p less than 0.01). Atherosclerosis of the ascending aorta was identified intraoperatively in 25 (18.3%) cases. Practically, the specificity of CT findings was excellent (98.3%), but the sensitivity was less satisfactory (72.0%) due to the presence of atherosclerosis without calcification. In cases of arteriosclerosis of the ascending aorta, great care was taken to prevent embolism secondary to a dislodged atheromatous plaque. The "aortic no-touch technique", with in situ internal thoracic artery and right gastroepiploic artery anastomosis under ventricular fibrillation, was performed in 6 cases, a single aortic cross-clamp was applied in 19 cases, and conventional methods were employed when the ascending aorta was normal or the "no-touch" or "single-clamp" procedure could not be used (control, 111 cases). No neurologic complications occurred in the "no-touch" group, while 2 cerebral infarctions occurred in the single-clamp group (10.5%) and the control group (1.8%) respectively. These differences between groups was not significant. Patients with a calcified ascending aorta are at higher risk for neurologic complications of coronary bypass. The risk can be decreased by minimizing surgical trauma to the ascending aorta by the use of "no-touch" techniques.

Adult↗
PubMed1992

[An adult case of dyspnea and overinflation of the residual lung with disappearance of the postpneumonectomy space after left pneumonectomy].

Mediastinal shift and overinflation of the residual lung after pneumonectomy are well known, and sometimes cause pulmonary insufficiency. However, most of such cases occur after surgery in childhood or adolescence. We present a 49-year-old woman who had dyspnea and severe overinflation of the residual lung after left pneumonectomy. She had undergone pneumonectomy at the age of 33 years. Dyspnea on exertion occurred 4 years later, and became much more severe 9 years later (H-J IV degrees). Computed tomography showed that the postpneumonectomy space and completely disappeared and the right lung was overinflated to the left posterior axillary line. Low vital capacity with high residual volume and low maximal ventilatory volume were detected by pulmonary function test. Pulmonary function after pneumonectomy is difficult to predict because mediastinal shift and overinflation of the residual lung may occur. To avoid this, prosthesis plombage for the postpneumonectomy space is necessary.

Dyspnea↗
PubMed1992

[A case of pulmonary leiomyosarcoma followed up for five years].

A 70-year-old woman with leiomyosarcoma, followed up for 5 years as tuberculoma, is described. The tumor, in the left lower lobe, had enlarged from 1.5 x 1.5 cm to 3.4 x 3.4 cm in 5 years, and doubling time was calculated to be 540 days. Another tumor (1.8 x 1.8 cm) was also recognized in the right lower lobe at the later time. Since not only a benign tumor but metastatic disease was suspected, thoracotomy was performed, and the intraoperative pathologic diagnosis was leiomyosarcoma. However, only partial lung resection was performed because of the low growth rate of the tumor, the patient's advanced age, limited lymphatic metastasis and favorable prognosis with only partial resection. DNA analysis of the tumor based on flow cytometry showed a diploid pattern, and this was thought to account for the long doubling time of the tumor. The postoperative course was satisfactory without any signs of recurrence at the operation site.

Aged↗
PubMed1992

Signal transduction cascade shared by epidermal growth factor and platelet-derived growth factor is a major pathway for oncogenic transformation in NRK cells.

We have isolated two recessive, mutually complementary NRK cell mutants that are refractory to transformation by epidermal growth factor (EGF) and transforming growth factor-beta. Both mutants are defective in a signal transduction cascade shared by EGF and platelet-derived growth factor (PDGF). Analysis of the mutants suggests that transformation of NRK cells by the v-fms, v-erbB, activated erbB-2, v-ras, v-fos, v-mos, v-fes, v-src, SV40 large T, polyomavirus middle T, and human papillomavirus type 16 E6,E7 oncogenes is mediated by the EGF/PDGF signal cascade. The data also suggest that the EGF/PDGF cascade branches into mitogenic and oncogenic signals, the latter of which is required for soft agar growth and focus formation.

Animals↗
PubMed1992

Oncogenic signal-induced ability to enter S phase in the absence of anchorage is the mechanism for the growth of transformed NRK cells in soft agar.

Upon neoplastic transformation, cells acquire the ability to grow in soft agar. We investigated how this occurs by cell cycle analysis of a rat cell line NRK-49F and its transformation-deficient mutants. Rapidly growing NRK and mutants arrest in G1 when deprived of anchorage by suspending in methylcellulose. Addition of epidermal growth factor (EGF) together with transforming growth factor-beta (TGF-beta), which is highly oncogenic to NRK, induces the rapid progression of G1-arrested NRK cells into S phase. The time course and the extent of synchronization are very similar to the cell cycle progression in the presence of anchorage. EGF alone, which is highly mitogenic but only slightly oncogenic, fails to induce such progression. Both mutants remain arrested in G1. These data indicate that oncogenic signals confer on NRK the ability to enter S phase in the absence of anchorage and that this is the principal mechanism for its ability to grow in soft agar.

Agar↗
PubMed1992

[Coronary artery bypass grafting by utilizing the artery grafts and bovine internal thoracic artery graft (Bioflow in an elderly patient)].

We performed coronary artery bypass grafting (CABG) in a 80-year-old male with calcified ascending aorta and severe varicose veins utilizing the bilateral internal thoracic arteries and the right gastroepiploic artery under fibrillatory arrest without aortic cross-clamp (aortic no-touch technique). After triple coronary artery bypass grafting was completed, heart failure occurred. Additional Bioflow graft to the circumflex artery restored good cardiac function. The aortic no-touch technique is a useful method for CABG in patients with severe calcified ascending aorta. This experience suggests that the Bioflow graft is a helpful conduit at an urgent situation in CABG.

Aged↗
PubMed1992

[A case of miliary tuberculosis and chest wall cold tuberculous abscess with contents draining into the epidural space].

A 37-year-old man was admitted because of miliary tuberculosis. However, his fever and general condition did not improve with chemotherapy. Six months later, paraplegia occurred following sudden radicular back pain without any alteration of segmental sensation. There were no abnormal findings on X-ray films of the thoracic and lumbar vertebrae. Examination by magnetic resonance imaging revealed that the contents of a cold tuberculous abscess in the right chest wall had drained into the epidural space through the intervertebral foramen. Drainage of the chest wall abscess and laminectomy were performed. Further investigation showed that this case did not belong to the usual type of atypical spinal tuberculosis reported previously.

Abscess↗