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Biomedical subjects

J C Ayus

Publications and source records attributed to J C Ayus.

At least 55 records · Page 3Linked to original sources
PubMed1985

Asymptomatic pericardial effusion in uremic patients: effect of long-term dialysis.

The present study was undertaken to determine the prevalence of asymptomatic pericardial effusion in a population with end-stage renal failure just prior to the initiation of chronic dialysis, and to determine the effect of long-term dialysis on these effusions. We prospectively studied 50 uremic patients with M-mode echocardiograms prior to initiation of chronic dialysis and followed 33 of these patients after 10 months of intense dialytic therapy. Predialysis effusion was present in 18/50 (36%) patients. Only 3/50 patients had clinical evidence of pericarditis (none of these individuals had an effusion). The incidence of clinical congestion and radiological evidence of volume overload was significantly higher in the patients with an asymptomatic pericardial effusion. Of these, the effusion disappeared on improved in 6 (43%), remained unchanged in 6 (43%), and worsened in 2 (14%). No patients developed new pericardise effusions during chronic dialysis. Changes in effusion size were related to changes in body weight between dialysis treatments (r = 0.39; p less than 0.05). Our data show that asymptomatic pericardial effusions are frequent in uremic patients prior to initiation of dialysis, the etiology of asymptomatic pericardial effusions in these patients appears to be related to volume overload, only 43% of the patients improved their effusions with chronic dialysis.

Adult↗
PubMed1985

Effect of minor surgery on urinary flow and electrolyte excretion in the awake dog.

Spontaneous variations in urinary flow and electrolyte excretion are well known to occur both in man and in the non-human primate. Data on these spontaneous variations is scarce in the dog, an animal which is widely used in physiological investigations. Our study was designed to characterize the spontaneous pattern of renal hemodynamics, urine flow and electrolyte excretion in the awake dog both under conditions of minimal surgical stress (group I), and after routine preparatory surgery (group II). Our results show significant spontaneous variation for urine flow and urinary excretion of Na, K, Cl, HCO3, Ca, PO4 and Mg for both groups of dogs. Urinary excretion of Na, K, PO4 and Mg was significantly higher for group II than for group I (p less than 0.05). Glomerular filtration rate and effective renal plasma flow (estimated from the clearance of p-aminohippurate) were measured in group II and showed no spontaneous variation. Our study shows that there is diurnal urinary electrolyte excretion variation in the dog which is exaggerated by small changes in the experimental protocol. These variations need to be considered when evaluating experimental maneuvers that induce changes in the renal handling of electrolytes in the dog.

Animals↗
PubMed1984

Effects of head-out water immersion on the urinary excretion of phosphate, calcium and magnesium in the awake dog.

The present study was undertaken to define the effects of heat-out water immersion on the urinary excretion of phosphate (UPO4V), calcium (UCaV), and magnesium (UMgV) in the awake dog. 53 dogs were divided into three groups: group I, time-control, from 10 a.m. to 4 p.m.; group II, immersion for 2 h, studied from 10 a.m. to 4 p.m., and group III, immersion for 2 h, studied from 4 p.m. to 10 p.m. Our results show that head-out water immersion did not alter the spontaneous pattern of UPO4V. When immersion was performed from 1 p.m. to 3. p.m. (group II), it had no effect on UCaV but induced a significant increase in UMgV although fractional excretion of Mg (FEMg) remained unchanged. When immersion was performed from 7 p.m. to 9 p.m. (group III), however, both UCaV and UMgV increased significantly. FECa also increased significantly in this group but FEMg again remained unchanged. The changes in UCaV were dissociated with UNaV. Changes in plasma PO4 (PPO4) and arterial pH were unrelated to changes in UCaV or UPO4V. Our findings show that head-out water immersion induces significant increases in UCaV and UMgV by mechanisms which are independent of parathyroid hormone (PTH) or acid base changes. The rise in UMgV seems to be related to an increase in the filtered load, while the increases in UCaV are secondary to changes in the renal tubular handling of calcium. Thus, under these experimental circumstances, Ca and Mg reabsorption seem to occur via different distal tubular pathways.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Cardiopulmonary toxicity in patients with breast carcinoma during plasma perfusion over immobilized protein A. Pathophysiology of reaction and attenuating methods.

Tumoricidal reactions in dogs with spontaneous breast carcinoma occur after perfusion of plasma over protein A derived from Staphylococcus aureus and immobilized in collodion charcoal. When this treatment was extended to humans with breast cancer, hemodynamic and physiologic changes were noted. The evolution and spectrum of these reactions were evaluated during 47 plasma infusions in five patients. Initial treatment conditions consisting of rapid perfusion of plasma over high quantities of immobilized protein A were employed for 12 treatments in two patients. Within 30 minutes after treatments were begun, mean blood pressure, systemic vascular resistance, and stroke volume increased, as did heart rate, cardiac output, and rectal temperature; however, mean pulmonary artery pressure and total pulmonary resistance did not change. At 90 minutes, hypotension developed (lowest mean blood pressure was 59 +/- 14 mm Hg) that was associated with a decrease in systemic vascular resistance and total pulmonary resistance (536 +/- 66 and 146 +/- 44 dynes . second . cm-5, respectively). Cardiac output increased, tachycardia developed, stroke volume decreased, and rectal temperature increased. During the hypotensive phase, values of creatinine clearance and fractional excretion of sodium diminished. Noncardiogenic pulmonary edema appeared occasionally, with bronchospasm noted once. No hemodynamic changes were seen when saline solution was passaged over protein A immobilized in collodion charcoal or when autologous plasma was given without passage over protein A immobilized in collodion charcoal. Treatment conditions were modified by diminishing protein A quantity and plasma volume and slowing plasma perfusion rate, which resulted in significant attenuation of all cardiopulmonary responses. This report, then, defines for the first time the physiologic basis of the cardiopulmonary toxicity in humans after plasma perfusion over immobilized protein A.

Breast Neoplasms↗
PubMed1983

Efficacy of intravenous vancomycin in the treatment of gram-positive peritonitis in long-term peritoneal dialysis.

Peritonitis is the major complication of long-term peritoneal dialysis. Gram-positive bacteria are responsible for two thirds of the total number of peritonitis episodes. Conventional therapy consists of daily administration of antibiotics, either parenterally or intraperitoneally. Vancomycin, an antibiotic with a prolonged half-life in renal failure, has a wide spectrum of activity against gram-positive bacteria and diffuses readily across the peritoneal membrane. In the present study, 82 percent of gram-positive peritonitis episodes were cured following the intravenous administration of vancomycin at weekly intervals. This cure rate compares favorably with that obtained following conventional therapy of peritonitis. It is concluded that intravenous vancomycin is an effective treatment for gram-positive peritonitis in patients undergoing long-term peritoneal dialysis. This form of therapy is convenient, reduces hospitalization, minimizes cost, and avoids possible contamination of the peritoneal dialysate used during the intraperitoneal administration of antibiotics.

Bacteria↗
PubMed1982

Rapid correction of severe hyponatremia with intravenous hypertonic saline solution.

Severe hyponatremia with hypoosmolality carries a high morbidity and mortality and constitutes a life-threatening emergency. We report seen cases of severe hyponatremia (serum sodium concentration 99.7 +/- 3.0 meg/liter) (mean +/- SEM) with hypoosmolality (212 +/- i mOsm/kg water) that presented with severe neurologic complications. Serum sodium concentration was corrected in 13.3 +/- 2.2 hours to mildly hyponatremic levels (serum sodium concentration 128.3 +/- 1.6 meq/liter). The rate of correction of serum sodium concentration was 2.4 +/- 0.5 meq!liter/hr. This was achieved by the intravenous administration of 3 percent hypertonic saline solution (687 +/- 43 meq sodium chloride) and furosemide or by hemodialysis where indicated. No complications occurred from treatment and all of our patients recovered without neurologic sequelae. Early diagnosis and rapid correction of serum sodium concentration appear to reduce the significant morbidity and mortality of severe hyponatremia.

Adult↗
PubMed1982

Renal papillary necrosis: an update.

The clinical and diagnostic features of renal papillary necrosis (RPN) of 27 patients were studied. Diabetes mellitus was the most frequent (56%) condition associated with RPN. Analgesic abuse, sickle hemoglobinopathy and urinary tract obstruction were present in 4 patients each; in 6 of these 12 patients these conditions were present as a coexistent disease with diabetes mellitus. There was evidence of an acute or chronic infection of the urinary tract in 18 patients, as a coexistent condition with another underlying disease that itself can cause RPN in 14 patients and as the only cause of RPN in another 4. Thus, the presence of more than one diagnostic condition which might be implicated in the causation of RPN was present in 15 patients or 55% of the cases in this series. When infection was excluded, six patients or 22% of the cases had two coexisting diseases, each of which has been implicated as a cause of RPN. This observation underlines the multifactorial nature of this entity and might explain why RPN is not encountered more frequently in each of the various primary diseases with which it has been associated. The average age of the patients at the time of diagnosis was 53 years for women and 56 years for men. Only six of the patients were younger than 40 years, and three of these had sickle hemoglobinopathy. The diagnosis of RPN was based on x-ray findings in eight patients, on the histologic examination of papillary tissue in urine in one, and on autopsy findings in the rest. Papillary necrosis was bilateral in three-fourths of the cases. The clinical picture varied. Most of the patients (67%) presented with chills and fever. Flank pain and dysuria were present in 11 patients (41%). As a rule oliguria was rare and progressive uremia was uncommon. In cases diagnosed at post-mortem, the patients had succumbed to infection or to a primary severe extrarenal disorder with the possibility of RPN having been entertained clinically in only half these cases prior to autopsy.

Adolescent↗
PubMed1982

Hemodynamic and renal functional changes after acute unilateral nephrectomy in the dog: role of carotid sinus baroreceptors.

We examined the role of the carotid sinus baroreceptors in the hemodynamic and renal functional changes initiated by acute unilateral nephrectomy (AUN). In 15 anesthetized dogs, AUN caused increases in sodium (UNaV) and potassium excretion (UKV) without significant changes in GFR, renal blood flow, or mean arterial pressure. Cardiac output (CO) was measured in five of these animals and decreased from 2.5 +/- 0.2 to 1.9 +/- 0.3 liter/min as total peripheral resistance (TPR) increased. In 11 dogs with bilateral acute surgical carotid sinus denervation, AUN failed to cause any change in renal hemodynamics, UNaV, or UKV that could be distinguished from sham-operated time controls. CO was measured in seven of these dogs and also did not change. AUN caused an immediate, transient elevation in blood pressure that returned to control levels 15 min after nephrectomy. When bilateral carotid occlusion (BCO) was carried out prior to AUN in animals with intact carotid sinus baroreceptors, AUN again caused an immediate increase in blood pressure but no changes in CO or electrolyte excretion. In separate studies, AUN increased UNaV and UKV significantly; when BCO was then carried out after AUN, cation excretion remained elevated. In seven dogs undergoing continuous perfusion of the carotid circulation bilaterally at constant pressure, AUN again failed to increase cation excretion despite a 30 mmHg rise in arterial blood pressure. These studies demonstrate that AUN fails to initiate hemodynamic or compensatory renal functional changes in dogs with bilateral carotid sinus denervation or in animals in which intact baroreceptors are shielded from the systemic circulation by BCO or perfusion at constant pressure, indicating the importance of these baroreceptors in the early changes after AUN.

Afferent Pathways↗
PubMed1981

Nephrotic syndrome developing after bee stings.

We have described a case, with renal biopsy findings and serologic studies, of a patient who had the nephrotic syndrome after sustaining multiple bee stings and who demonstrated a favorable response to steroid therapy. Bee stings have previously been implicated in the development of this syndrome, though the reported cases in the literature are poorly documented.

Adult↗
PubMed1980

Alkalemia associated with renal failure. Correction by hemodialysis with low-bicarbonate dialysate.

Hemodialysis with a low-bicarbonate dialysate was used in four patients for the simultaneous treatment of acute renal failure and fluid overload associated with alkalemia. All patients had a mixed acid-base disorder, namely respiratory alkalosis superimposed on metabolic alkalosis. Correction of alkalemia and azotemia was accomplished with low-bicarbonate dialysis without signs of hemodynamic deterioration. This successful experience, coupled with the reported side effects of acetate-containing dialysate, would suggest the use of a low-bicarbonate dialysate as a recommended therapy of renal failure associated with alkalemia.

Acute Kidney Injury↗
PubMed1979

Extracorporeal immunoadsorption: initial experience in human systemic lupus erythematosus.

Extracorporeal immunoadsorption and filtration was used in treatment of a 29-year-old woman with severe lupus nephritis. For the previous 35 days single-stranded DNA (ssDNA) antibody and immune-complex levels had been continuously raised with only partial improvement on prednisone therapy. Levels of immune complexes and ssDNA antibodies were substantially reduced by extracorporeal plasma filtration and adsorption of DNA collodion charcoal. There were no major clinical complications. After perfusion, the reduction of ssDNA binding and immune complexes in serum was sustained, serum C'3 became normal, and serum creatinine and proteinuria improved. 28 days after perfusion, subendothelial glomerular deposits were much reduced compared with those in a pre-perfusion biopsy specimen. Selective immunoadsorption is a promising new approach to persistent lupus nephritis refractory to drug therapy alone.

Adult↗
PubMed1979

Peritoneal clearance and total body elimination of vancomycin during chronic intermittent peritoneal dialysis.

Vancomycin is a useful antimicrobial agent in patients undergoing chronic hemodialysis treatment; its efficacy in chronic peritoneal dialysis (CPD) has not been established. Serum (VS) and peritoneal fluid (VPF) vancomycin concentrations were measured in two CPD patients with staphylococcal peritonitis. Half-life of VS agreed with the half-life of VPF in each patient, and the VS/VPF ratio was 1.27 in both patients. Distribution volumes were 37.2 and 58.7 l, values approximating total body water in these patients. VS and VPF persisted in the therapeutic range (greater than 5 microgram/ml) for more than 16 days. In one patient, mean peritoneal clearacne was 9.8 ml/min, and overall drug clearance averaged 2.3 ml/min; in the other patient, overall clearance was 2.1 ml/min. These results indicate that therapeutic vancomycin levels can be maintained for more than 16 days with a single 1 g intravenous dose in patients receiving intermittent CPD, as is the case for hemodialysis patients. Because of this, parenteral vancomycin is useful in the treatment of staphylococcal peritonitis in CPD patients.

Adult↗