Biomedical subjects
Publications and source records attributed to S Yuasa.
A 64-year-old man with total occlusion of the left main coronary artery associated with acute anterior infarction was treated successfully with combined emergency intracoronary thrombolysis and coronary bypass surgery. Postoperative angiography demonstrated patent bypass grafts with good preservation of left ventricular function.
We studied on coagulation and fibrinolysis systems during pregnancy by measuring plasma levels of thrombin-antithrombin III complex (TAT), plasmin-alpha 2 plasmin inhibitor complex (PIC), fibrinogen/fibrin degradation products (FDP), plasminogen (PLG) and antithrombin III (AT-III). Ninety seven pregnant, 5 post-delivery and 32 nonpregnant women aged from 20 to 52 years old were included in this study. Plasma concentrations of TAT and PIC in nonpregnant women were 3.38 +/- 1.02 micrograms/l and 0.65 +/- 0.24 micrograms/ml, respectively. TAT gradually increased with the progression of pregnancy and rapidly decreased after the delivery. Whereas PIC and AT-III concentrations did not change significantly during pregnancy. Fibrinogen, PLG and FDP concentrations changed similarly as TAT. Eight pregnants whose plasma PIC concentrations elevated more than 1.0 micrograms/l were further examined. In 6 women out of them (71.5%), FDP concentrations were elevated. In this particular group of subjects, however, they delivered normally without complications such as toxemia. These observations suggest that, at least, a hypercoagulative state progresses with pregnancy, being normalized after the delivery. Although we could not find the relationship between the hypercoagulation and clinical complications such as thrombosis and toxemia of pregnancy, present findings suggest that special caution should be paid on the pregnants whose TAT and FDP levels are elevated.
OBJECTIVE: The present study was carried out to examine the involvement of dopamine in the pressure-natriuresis phenomenon which has been postulated as a major regulator of extracellular fluid volume and thereby arterial pressure. DESIGN: Dopaminergic modulation of the pressure-natriuresis response was studied in the innervated and denervated rat kidney, to allow a distinction between the effects of neural and extraneural dopamine. METHODS: The pressure-natriuresis response was studied in anesthetized Sprague-Dawley rats, in which neural and hormonal influences on the kidney were fixed by denervating the kidney and by intravenous infusion of aldosterone, hydrocortisone, vasopressin and norepinephrine. The innervation to the kidney remained intact in some experiments with the selective dopamine-1 antagonist SCH 23390. Urinary excretion of dopamine during the pressure-natriuresis response was also examined in the innervated and denervated rat kidney. RESULTS: Although infusion of dopamine at a dose of 2 micrograms/kg per min had no effect on the pressure-natriuresis response in rats in which neural and hormonal influences on the kidney were fixed, the slopes of the relations between urine flow, sodium excretion and mean arterial pressure in rats given 10 micrograms/kg per min dopamine were significantly greater than those found in the control rats. Renal plasma flow increased significantly in the dopamine-treated rats whilst glomerular filtration rate did not differ between the control and dopamine-treated rats. The dopamine-induced increase in the slope of pressure-natriuresis relationship and renal plasma flow were completely blocked by 0.5 micrograms/kg per min SCH 23390. However, infusion of SCH 23390 alone at 0.5 micrograms/kg per min did not significantly alter the pressure-natriuresis response in rats with either denervated or innervated kidney. In addition, urinary excretion of dopamine derived from neither neural nor extraneural origins was altered in parallel with variations in mean arterial pressure. CONCLUSION: These results suggest that exogenous administration of dopamine may affect the pressure-natriuresis response by altering the magnitude of arterial pressure-induced changes in tubular sodium reabsorption, via an action of dopamine-1 receptors. However, endogenous dopamine does not appear to be capable of modulating the pressure-natriuresis response.
Of 167 patients, who underwent cardiac surgery using topical ice slush, 21 (12.6%) were found to have phrenic nerve palsy postoperatively. In addition, two patients showed severe epigastric discomfort, such as nausea, vomiting and gastric distension. These symptoms were consistent with so called "gastric ileus", first reported by Spencer et al. The injury of thoracic vagi induced by topical ice slush might be related to the development of this complication.
The phasic renal arterial blood flow velocity was measured using a Doppler-Based Toshiba SSH-160A scanner in 25 healthy subjects and 78 patients with chronic glomerulonephritis. Renal arterial blood flow at the renal hilum was visualized with color Doppler ultrasound, and the velocity waveform was obtained by pulsed Doppler ultrasound. The velocity waveform was then analyzed to give the peak systolic velocity (S), end-diastolic velocity (D), resistive index (RI), and pulsatility index (PI). Creatinine clearance correlated with S (r = 0.76), D (r = 0.80), RI (r = -0.74), and PI (r = -0.85). The split renal glomerular filtration rate, calculated by a method which makes use of the early renal uptake of Tc-99m DTPA, also correlated well with these parameters. These findings suggest that renal arterial blood flow as detected by Doppler ultrasound may be useful for the noninvasive, direct, rapid, and simple evaluation of renal hemodynamics and renal function, although various modifying factors also need to be considered.
The mode of Purkinje cell migration in the mouse cerebellar primordium was examined immunohistochemically, by marking Purkinje cells with anti-spot 35 antibody and labeling them with 5'-bromodeoxyuridine. The cells migrated radially from the neuroepithelium of the fourth ventricle towards the cortical surface between the 13th and 17th days (E13-E17) of gestation. Regional differences in the migratory process were evident: the final settlement of the Purkinje cells proceeded earlier in the lateral and posterior parts of the primordium, exhibiting latero-medial and posteroventral-anterodorsal diminishing sequences. To elucidate the factors involved in the migration, the arrangement of radial glial fibers, and expression of the cell adhesion molecule, tenascin, were examined immunohistochemically with the monoclonal antibody 1D11, a marker for both immature and mature astroglia, and an anti-tenascin antibody. At E14, 1D11-immunopositive fibers were seen to extend from the ventricle to the pial surface, and the cell bodies of immature glia migrated after E15 towards the cortex, shortening the radial processes whose end-feet were attached to the pia mater. Tenascin, which possesses a neuron-glial adhesiveness, was also expressed on the radial fibers during the migration of the Purkinje cells. The fibers were closely apposed to the migratory Purkinje cells, and their arrangement and orientation accorded with the migratory direction of the Purkinje cells. Further, changes in the molecular species of antigens detected by both the 1D11 and anti-tenascin antibodies were observed by immunoblotting analysis during the course of cerebellar development. These findings suggest that the arrangement of radial glia and expression of adhesion molecules may be involved in the control and guidance of Purkinje cell migration.
Antibodies to the envelope proteins of duck hepatitis B virus neutralize viral infection in vitro. Using a library of murine monoclonal antibodies (Mabs) against the envelope proteins, we previously identified four neutralizing and two non-neutralizing epitopes on the pre-S region of the large envelope proteins. In this study we report the localization of all but one of these epitopes at the amino acid level. All but 28 nucleotides of the pre-S and S genes were cloned in pUC vectors and expressed in Escherichia coli. All Mabs in this study reacted with the expressed gene products in Western blots. Deletion mutants of the pre-S region were generated and their expressed products tested on Western blots for reactivity with the Mabs. Of the three epitopes involved in neutralization, the epitope found to be immunodominant in convalescent ducks was localized to nine amino acids of the middle portion of the pre-S gene product, while a second epitope was mapped to nine amino acids upstream of the immunodominant epitope and the third epitope to seven amino acids adjacent to the S gene. One of the two non-neutralizing epitopes was located between the two groups of neutralizing epitopes while the other mapped to the same region as one of the neutralizing epitopes. Our data indicate that several regions of the pre-S polypeptide may play a role in neutralization of hepadnaviruses.
The diagnosis of a renal arteriovenous fistula is usually confirmed by angiography. Described is the utilization of color Doppler ultrasound to monitor a renal arteriovenous fistula before and after treatment by transcatheter steel coil embolization in a 63-year-old woman. Using color Doppler, the arteriovenous fistula with an aneurysmal lesion was clearly visualized. A pulsed-wave Doppler analysis showed increased flow velocity and decreased pulsatility in the supplying artery. After successful transcatheter occlusion of the fistula, these findings disappeared. The Doppler ultrasound technique is likely to be useful to detect and monitor a renal arteriovenous fistula noninvasively, simply, and quickly.
We evaluated total and split renal functions from the pattern for renal arterial blood flow detected by ultrasound Doppler in healthy subjects and patients with varying degrees of renal function and disorders other than renovascular hypertension or severe aortic valvular disease. A renal-time pulsed ultrasonic echo-Doppler device at 2.5 MHz was used with a translumbar approach. The ratio of peak diastolic (D) to systolic (S) velocity correlated well with both p-aminohippurate clearance and creatinine clearance. Acceleration time was correlated with the clearance of neither compound. To evaluate the clinical usefulness of ultrasound Doppler in the assessment of split renal function, we compared the D/S ratio with the renal function obtained by radionuclide methods for individuals. The split renal glomerular filtration rate, calculated by a method which makes use of the early renal uptake of 99mTc-diethylenetriam-inepentaacetic acid, correlated well with the D/S ratio. These results indicate that the ultrasonic measurement of renal arterial blood flow by the pulsed Doppler method should be useful for assessment of total and split renal functions.
A case of intraaortic balloon entrapment is reported. To our knowledge, this is the tenth case in the literature. We conclude that balloon entrapment can occur without any signs of rupture of the balloon and that the balloon should be removed surgically.
The efficacy, safety, and pharmacokinetics of carvedilol were investigated in an open trial performed on six patients with hypertension and chronic renal failure requiring hemodialysis. The plasma level of unchanged carvedilol after a single dose of 10 mg reached a peak 1-5 h after administration both on days with and without hemodialysis. The drug was gradually metabolized thereafter and had almost disappeared from the plasma after 24 h. Blood pressure was lowered by carvedilol both on days with and without hemodialysis. No carvedilol passed through the dialysis membrane. During the 4-week administration period of carvedilol at 10 mg/day, assessment of plasma samples taken just prior to early morning administration demonstrated no drug accumulation. Blood pressure was well controlled during the administration period. Tolerance to the antihypertensive effect was not observed. Heart rate was not significantly changed at any time. There were no side effects in any of the patients during the trial, and laboratory parameters remained unchanged. These results indicate that carvedilol is a safe and effective antihypertensive agent for use in patients on chronic hemodialysis.
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We examined the diuretic action of orally administered azosemide (AZ: 60 mg) and furosemide (FM: 40 mg) and their effects on body fluid distribution and circulatory vasoactive hormones in normal male volunteers. Urine volume and urinary sodium excretion were increased, peaking during 0 to 2 hours in FM and 2 to 4 hours in AZ in response to administration of both diuretics. The cumulative urine volume and urinary sodium excretion for 8 hours showed no significant difference between AZ and FM. Total body water (TBW) was measured by the dynamic distribution of deuterium oxide and a percentage change in circulating plasma volume (ICG ratio) was determined by using indocyanine green. The decrease in TBW and ICG ratio was detected in proportion to the increase in urine volume after administration of AZ and FM. Plasma renin activity (PRA) and plasma concentration of aldosterone (PAC), angiotensin II (ANG II) and arginine vasopressin (AVP) were elevated in response to the reduction in ICG ratio by both diuretics. The responses of PRA, PAC and ANG II to AZ were delayed about 2 hours as compared with those of FM. The increase in AVP with FM was significantly greater than that with AZ detected 2 hours after administration. The elevation of AVP in AZ was delayed and blunted compared with FM. These data indicate that the difference in diuretic property of AZ and FM may induce different stimulation to the secretion of vasoactive hormones through the changes in body fluid distribution and these hormones might modify the anti-edematic effect of AZ and FM.
The importance of age at menarche, age at menopause, height, and obesity as risk factors for breast cancer, and the possible interactions among these factors in breast cancer causation were investigated in a data set collected in the late 1960's, in an international multicenter case-control study. Multiple logistic regression procedures were used to model data from 3,993 breast cancer cases and 11,783 controls from 7 study centers representing the range of international variation of breast cancer incidence. Height and obesity (measured through the weight/height2 index) were independent risk factors for breast cancer among post-menopausal but not pre-menopausal women; post-menopausal women taller by 10 cm had a 12% higher risk of breast cancer (95% confidence interval, CI, 3-21%) and post-menopausal women of average height (say 158 cm) had an 11% higher risk of breast cancer (CI 7-16%) when they were heavier by 10 kg (and, therefore, more obese by 4 kg/m2). Age at menarche was a risk factor among both pre-menopausal and post-menopausal women, a delay of 2 years corresponding to a 10% reduction in breast cancer risk (CI 6-15%). Age at menopause was also a breast cancer risk factor, women with menopause at each 5 year age difference having a 17% higher risk of breast cancer (CI 11-22%). There is evidence of an interaction (deviation from the logistic regression-postulated multiplicativity) between obesity and age at menarche, implying that the protective effect of late menarche may not apply to overweight women or that late menarche may become detrimental in obese women. The estimated relative risk coefficients, when applied to average risk factor levels observed among control women, can explain only a small fraction of the difference in breast cancer incidence between Boston and Tokyo.
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