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Biomedical subjects

S Tobe

Publications and source records attributed to S Tobe.

48 records · Page 3Linked to original sources
PubMed1991

Muscle sympathetic nerve activity and renal responsiveness to atrial natriuretic factor during the development of hepatic ascites.

PURPOSE: Sodium retention in cirrhosis has been attributed to an imbalance between vasoconstrictive antinatriuretic forces such as the sympathetic nervous system and vasodilatory natriuretic agents such as atrial natriuretic factor (ANF). With the development of refractory ascites, cirrhotic patients become unresponsive to the natriuretic effect of ANF. Animal data suggest that the sympathetic nervous system plays a key role in mediating the refractoriness to ANF. We therefore studied the relationship between sympathetic nerve activity (SNA) and the natriuretic response to ANF in normal subjects and cirrhotic patients. We also attempted to localize the intrarenal site of refractoriness to ANF by lithium clearance. PATIENTS AND METHODS: Twenty-six patients with biopsy-proven cirrhosis and seven age- and sex-matched normal volunteers were studied after a week of 20 mmol/day sodium intake and no diuretics. Muscle SNA was recorded from the peroneal nerve (microneurography) and correlated with responsiveness to a 2-hour ANF infusion. Lithium clearance was used as a marker of sodium reabsorption proximal to the intramedullary collecting duct, the main site of ANF action. Plasma norepinephrine, renin, and aldosterone levels were also determined. Patients were categorized into three groups: nine patients free of ascites (by ultrasonography), five ascitic patients who responded to a 2-hour ANF infusion (i.e., had a natriuretic response to ANF above 0.83 mmol/hour), and 12 ascitic patients who did not respond. RESULTS: Muscle SNA was greatly increased in the ascitic nonresponder patients compared with the normal subjects (64 +/- 4 versus 27 +/- 7 bursts/minute, p less than 0.001), moderately increased in ascitic responders (47 +/- 6 bursts/minute, p less than 0.05), but not significantly increased in nonascitic patients with cirrhosis (34 +/- 5 bursts/minute). SNA was positively correlated with plasma norepinephrine levels (r = 0.69; p less than 0.005) and inversely correlated with peak sodium excretion during the ANF infusion (r = -0.63; p less than 0.001). Plasma renin activity and aldosterone were markedly elevated in ascitic nonresponders, and normal in ascitic responders and nonascitic patients. Lithium clearance was reduced in ascitic patients compared with nonascitic patients, did not change after the ANF infusion, and correlated inversely with SNA (r = -0.61; p less than 0.01). CONCLUSION: These results support the concept that the sympathetic nervous system is a factor in renal sodium handling in cirrhosis, especially in the initiation of sodium retention and the development of refractory ascites. Refractoriness to ANF might be explained, at least in part, by increased neurally mediated sodium reabsorption proximal to the intramedullary collecting duct, the main site of ANF action.

Adult↗
PubMed1991

Glue-sniffing and distal renal tubular acidosis: sticking to the facts.

An index case is presented to introduce the subject of the acid-base and electrolyte abnormalities resulting from toluene abuse. These include metabolic acidosis associated with a normal anion gap and excessive loss of sodium and potassium in the urine. The major question addressed is, what is the basis for the metabolic acidosis? Overproduction of hippuric acid resulting from the metabolism of toluene plays a more important role in the genesis of the metabolic acidosis than was previously believed. This conclusion is supported by the observation that the rate of excretion of ammonium was not low during metabolic acidosis in six of eight patients, suggesting that distal renal tubular acidosis was not an important acid-base abnormality in most cases where ammonium was measured. The excretion of hippurate in the urine unmatched by ammonium also mandates an enhanced rate of excretion of the cations, sodium and potassium. The loss of sodium causes extracellular fluid volume contraction and a fall in the glomerular filtration rate, which may transform the normal anion gap type of metabolic acidosis into one with a high anion gap (accumulation of hippurate and other anions). Continuing loss of potassium in the urine leads to hypokalemia. An understanding of the metabolism of toluene provides the basis for the unusual biochemical abnormalities seen with abuse of this solvent.

Acid-Base Equilibrium↗
PubMed1991

Characterization of peritoneal transport in patients with failed renal allografts receiving CAPD.

Many patients with failed renal transplants elect to receive continuous ambulatory peritoneal dialysis (CAPD) as their modality of dialysis. For others, cardiovascular considerations or access difficulties make CAPD a necessary option when these patients return to dialysis. It is unclear what effects renal transplantation, chronic immunosuppressive therapy and graft rejection might have on the integrity of the peritoneal membrane. We report on thirteen patients receiving CAPD who had peritoneal equilibration test (PET) studies after a failed renal transplant. Three of these patients had studies done pre and post transplantation. Our solute equilibration studies demonstrated that for 10 patients studied with the older 4.25% technique the mean post transplantation D/P creatinine was 0.688 (SE:0.039) on the border of high and low average, and the mean D/Do glucose was 0.228 (SE:0.024) in the high transporter range. Three patients tested pre and post transplantation (upon their return to CAPD after graft failure) had no change in these values. From the above data, 13 patients with peritoneal equilibration testing post transplantation have well-functioning peritoneal membranes allowing for adequate dialysis and flexibility in dialysis prescription. We conclude that renal transplantation does not adversely affect peritoneal membrane function if these patients return to CAPD after graft failure.

Biological Transport↗
PubMed1991

[Experimental studies on the effects of superoxide dismutase on warm ischemic-reperfusion injury of the lung].

Transient impairment of the transplanted lung in early postoperative period is one of difficult problems in lung transplantation. It is likely that reperfusion injury of the warm ischemic lung is contributory. The purpose of this study is to evaluate the effects of superoxide dismutase (SOD) on reperfusion injury of warm ischemic lung. Thirty mongrel dogs were divided into four groups. In group I (n = 6), the left lung with complete hilar stripping was placed in warm ischemic state under deflation for 1 hour. In group II (n = 9), the left lung with complete hilar stripping was kept in warm ischemic condition under inflation. Group III (n = 6) animals with same manipulation as group I received superoxide dismutase (SOD 20 mg/kg) before reperfusion. Group IV (n = 9) animals underwent same manipulation as group II and received SOD (20 mg/kg) before reperfusion. Before warm ischemia, immediately after reperfusion, and 1 and 2 hours, blood gases, left pulmonary vascular resistance were measured under the occlusion of right pulmonary artery. Extra vascular lung water content (EVLW) was measured at autopsy and lung was processed for histology. In group II, III and IV, blood gases and EVLW showed significantly better values than group I. In group I and III, left pulmonary vascular resistance increased prominently after reperfusion, however did not change in group II and IV. From these results, we concluded that inflated lung reduced the extent of pulmonary edema after reperfusion and SOD was effective in preventing warm ischemic damage even in deflated lung.

Animals↗
PubMed1991

[A preview of the practical application of hybrid artificial liver].

In order to replace the liver function, the development of the system where natural hepatocytes are immobilized in a matrix polymer might be considered as the best way. Each hepatocyte has a number of specific receptors for several ligards. We noticed that the hepatocyte recognizes the structure of oligosaccharides via asialoglycoprotein receptors and synthesizes lactose-carrying styrene polymer (PVLA) as a asialoglycoprotein model. On PVLA-coated dish, the specific functions as well as attachment of hepatocyte were successfully maintained. Moreover, cultured hepatocytes on PVLA substratum started gradual movement, and then remarkably formed multilayer aggregations which had long-term survival. Hepatocytes in the aggregation exhibited better maintenance of specific hepatocyte-functions such as the synthesis of albumin and secretion of bile acid, and retained mitochondrial enzyme activity than those in the monolayer culture on collagen and fibronectin. Furthermore, we found that DNA synthesis in cultured hepatocytes was correlated to the cell-shape which could be controlled by the concentration of PVLA substratum. These results also suggested that the PVLA could potentiate the regulation of the differentiation and proliferation of hepatocytes.

Artificial Organs↗
PubMed1991

[The effect of PGI2 and SOD on the reimplantation response after lung transplantation].

In order to improve the early postoperative pulmonary dysfunction caused by the reimplantation response after single lung transplantation, prostaglandin I2 (PGI2) and superoxide dismutase (SOD) were administered to dogs whose left lungs were subjected to complete hilar-stripping and then exposed to warm ischemia, or resected and replaced with allograft. Doppler flow probes were placed on the ascending aorta and on the left main pulmonary artery, and a Swan-Ganz catheter was introduced into the pulmonary trunk. Twenty five dogs were divided into 4 groups. Hilar stripping of the left lung with division and reanastomosis of the left main bronchus was performed in 7 dogs (Group 1). Hilar stripping of the left lung with division and reanastomosis of the left main bronchus was exposed to additional warm ischemia for one hour in 6 dogs (Group 2). Same surgical procedure as Group 2 with additional treatment by using PGI2 (1 micrograms/min/kg for 30 min). and SOD (20 mg/kg) was performed in 6 dogs (Group 3). Single lung transplantation with PGI2, SOD and immunosuppressive treatment (CyA 10 mg/kg and AZ 4 mg/kg daily for 2 weeks) was performed in 6 dogs (Group 4). The pulmonary arterial blood flow of the left lung and the cardiac output were serially measured by means of Doppler flow method for two weeks for studying the graft function in the early postoperative period. Findings of chest X-ray films and arterial blood gases were also studied for two weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Aortocoronary bypass for coronary ostial stenosis following aortic valve replacement: a report of successfully treated case].

A 62-year-old man underwent aortic valve replacement with a Medtronic-Hall valve (21 mm) for aortic stenosis and regurgitation with normal coronary arteries. An intermittent selective coronary perfusion with metal tip cannula was employed for both the coronary arteries. Postoperative course was uneventful. However, he began to complain of chest pain six months later. Cardiac catheterization and coronary arteriography revealed a normally functioning valve with 75% stenosis at the main trunk of the left coronary artery. Coronary bypass grafting using a saphenous vein was successfully performed to the left anterior descending coronary artery and the circumflex of the coronary artery. Whenever this fatal complication of the coronary ostial stenosis is recognized, earlier coronary revascularization should be recommended to save the severely ill patient.

Aortic Valve↗
PubMed1990

[Extensive surgical treatment of advanced or recurrent carcinoma of the thyroid gland: report of three cases].

Three advanced or recurrent thyroid carcinomas invading the adjacent surrounding organs such as trachea, great vessels or anterior mediastinum were reviewed. In one patient, resection of subtotal thyroid combined with trachea including a part of cricoid cartilage was performed, and followed with end to end anastomosis. In the other two patients with SVC syndrome, a trans-sternal surgical approach was applied in order to resect a large tumor extending into the anterior mediastinum. Replacement of SVC with ringed PTFE graft and chest wall resection was performed in one patient. With these extended surgical intervention, more operative radicality, prolonged surviving time and better quality of life were expected.

Adenocarcinoma↗
PubMed1989

[Surgical treatment of superior vena cava syndrome (SVC)].

SVC syndrome is occurred by the occlusion or stenosis of the superior vena cava secondary to malignant mediastinal tumor. Up to this report, surgical intervention has been thought to be difficult. Recently, extent of the tumor has been diagnosed exactly by CT scan, NMR, and angiography. Several cases undergoing complete resection of the tumor with the technique of vascular surgery have been reported. During the past 10 years, we have experienced 21 cases of SVC syndrome. 16 patients had operations and 5 patients had radiation or chemotherapy. The methods of operations were as follows: complete resection of the tumor 1, complete resection of the tumor and reconstruction of SVC 2, subtotal resection of the tumor and reconstruction of SVC 2, bypass of SVC only 5, extra-anatomical bypass 3. PTFE grafts were placed between right subclavian vein and SVC or left subclavian vein and right atrium. Extra-anatomical bypass were placed between jugular vein and femoral vein. PTFE bypass graft provides effective treatment for SVC obstruction with immediate and long term relief of SVC syndrome.

Aged↗
PubMedDate not supplied

The influence of marital adjustment on 3-year left ventricular mass and ambulatory blood pressure in mild hypertension.

BACKGROUND: Of psychosocial stressors, job strain has been associated with a sustained increase in blood pressure. The impact of marital factors on blood pressure and target organ has not been explored. OBJECTIVES: To evaluate whether marital adjustment, measured at baseline by self-report (Dyadic Adjustment Scale) influences left ventricular mass index (LVMI) and ambulatory blood pressure measured over 3 years in patients with mild hypertension. METHODS: A prospective cohort study was conducted on 103 cohabiting males or females, including 72 with technically adequate echocardiograms, who at baseline were unmedicated, employed, and living with a significant other, all for a minimum of 6 months and had repeated elevated office diastolic blood pressure. MAIN OUTCOME MEASURES: Left ventricular mass by M-mode echocardiography indexed to body surface area and blood pressure were measured by ambulatory blood pressure every 15 minutes (daytime) and hourly between 11 PM and 7 AM. RESULTS: Marital adjustment, smoking, drinking, and baseline LVMI contributed significantly to the prediction of 3-year LVMI (semipartial correlation, sr(2) = 0.04, 0.07, 0.03, and 0.22; P =.03,.008,.08, and <.001, respectively) together accounting for 36% of the total variability in follow-up LVMI. Three-year ambulatory blood pressure measures were not significantly related to marital adjustment but there were correlations with Dyadic Adjustment Scale subscales. Low or high levels of spousal contact during 3-year ambulatory blood pressure monitoring were associated with an increase or decrease of 3-year, 24-hour diastolic blood pressure, consistent with the quality of marital adjustment (P =.04) or marital satisfaction (Dyadic Adjustment Scale subscale, P =.008). CONCLUSIONS: In a cohort of subjects with mild essential hypertension, marital adjustment had an influence on 3-year LVMI. Depending on the quality of marital adjustment, spousal contact at 3 years was associated with an increase or decrease of 3-year diastolic blood pressure. Confirmation of these results, including objective marital assessment and the participation of normotensive subjects, is required. Arch Intern Med. 2000;160:3453-3458.

Adaptation, Psychological↗
PubMedDate not supplied

Blood urea levels 30 minutes before the end of dialysis are equivalent to equilibrated blood urea.

The steady decline in blood urea during high efficiency hemodialysis is followed by a rebound phase after dialysis in which the level of urea rises to an equilibrium value (Ct + 30) that may be up to 20% higher than the immediate post dialysis (Ct) concentration. The artificially low urea concentration immediately after dialysis leads to an overestimate of the efficiency of the dialysis calculated by Kt/V if the true equilibrium blood concentration of urea is not used in the calculation by the single-pool urea kinetic model. The measurement of equilibrium urea concentration requires a blood sample approximately 30 min after hemodialysis, which is an encumbrance on dialysis patients. This study was undertaken to determine whether an intradialytic sample taken 30 min before the end of dialysis (Ct - 30) may be representative of the equilibrium sample, and to compare the Kt/V using the Ct - 30 and Ct + 30 samples. Thirty-six patients were studied and blood urea concentrations were measured half an hour before the end of dialysis (Ct - 30), at the end of dialysis (Ct), and half an hour after the end of dialysis (Ct + 30). Kt/V (Daugirdas method) was calculated using urea concentration 30 min before the end of dialysis (Kt/Vt - 30) and was compared with Kt/V calculated using equilibrium urea concentration (Kt/Vt + 30). There were no significant differences between the Kt/Vt - 30 and the KtVt + 30 (1.25 versus 1.22, p = 0.65). The correlation between Kt/Vt - 30 and Kt/Vt + 30 was excellent with r2 = 0.93, regression y = 1.05 x -0.033. Kt/Vt - 30 also compared favorably with the Kt/V double pool method (Kt/Vdp) described by Daugirdas (1.25 versus 1.19, p = 0.23). Using the Ct - 30 to calculate Kt/V by the percent urea reduction methods of jindal (Kt/Vpru) decreases the Kt/V value by 0.14 on average, but it remains significantly higher than the Daugirdas method. The authors conclude that calculations using urea concentration 30 min before the end of dialysis improves the accuracy of dose estimation in high efficiency dialysis, without inconveniencing the patient.

Female↗