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Biomedical subjects

O S Better

Publications and source records attributed to O S Better.

At least 19 recordsLinked to original sources
PubMed1995

Systemic hypotension and renal failure in obstructive jaundice-mechanistic and therapeutic aspects.

The association between obstructive jaundice and postoperative acute renal failure has been originally described more than eight decades ago and is now a well-established clinical phenomenon. Acute renal failure occurs in 8 to 10% of patients requiring surgery for relief of obstructive jaundice and contributes to eventual mortality in 70 to 80% of those who develop it. A major factor that may underlie the susceptibility to renal failure in patients with obstructive jaundice is cardiovascular instability manifested as systemic hypotension and defective vascular reactivity. This article outlines the scope of the clinical association between jaundice and renal failure and reviews the clinical and experimental studies that have contributed to our understanding of the underlying pathophysiologic mechanisms for this phenomenon. A growing body of evidence emanating from these studies indicates that bile constituents (e.g., bile acids, bilirubin, cholesterol) do not exert a direct nephrotoxic effect. Rather, the retention of bile during cholestatic jaundice has deleterious effects on cardiovascular function and on blood volume. This, in turn, sensitizes the kidney to prerenal failure and acute tubular necrosis in postsurgical patients with obstructive jaundice. The institution of prophylactic measures based on the appreciation of these underlying pathogenic mechanisms may result in an improvement in the overall prognosis of jaundiced patients undergoing surgery.

Acute Kidney Injury↗
PubMed1994

Carcinoid tumor of the lung and type-1 multiple endocrine neoplasia associated with persistent hypercalcemia: a case report.

The clinical and laboratory data, and histologic, electron microscopic and immunocytochemical findings of a carcinoid tumor of the lung associated with parathyroid hyperplasia and persistent hypercalcemia are described. The carcinoid tumor consists of uniform cuboidal cells with regular round vesicular nuclei and eosinophilic granular cytoplasm. The tumor cells were chromogranin and neuron-specific enolase positive. The CAT scan of the abdomen revealed an adrenal mass, 3 cm in diameter, and an enlarged body in the pancreas. Our patient is still suffering from hypercalcemia and renal colic, despite repeated parathyroid gland removal, and enucleation of the lung mass. Recent parathyroid scintigraphy with Tc revealed an enlarged parathyroid gland. The thoracic CAT scan is normal. We believe that our patient is suffering from multiple endocrine neoplasia type-1 with persistent hypercalcemia due to hyperparathyroidism.

Carcinoid Tumor↗
PubMed1994

Circulatory disturbance and renal dysfunction in liver disease and in obstructive jaundice.

The appearance of hepatorenal syndrome in a patient with acute or chronic liver disease is associated with a dismal outcome. Thus, management of HRS remains a formidable challenge to the aggressiveness and perseverance of the physician. The best treatment for HRS remains prevention based on avoidance of circulating volume contraction or the use of nephrotoxic drugs. Treatment for established HRS remains a frustrating experience with recovery being rare. A successful liver transplantation is currently the only definitive treatment that can reverse HRS. As this procedure is being performed with increasing frequency and encouraging results, a new window of hope has been opened for these patients.

Adult↗
PubMed1993

Cardiac function and responsiveness to beta-adrenoceptor agonists in rats with obstructive jaundice.

The function and role of the heart and the contribution of cardiac beta-adrenoceptors in the pathogenesis of circulatory failure in obstructive jaundice were studied in the 3-day bile duct-ligated (BDL) rat using three different techniques to measure cardiac function and beta-adrenoceptor activity, number, and affinity. The techniques were the pithed rat preparation, the isolated working heart preparation, and a competitive radioligand binding assay for beta-adrenoceptors. The results of these experiments were compared with those obtained in 3-day bile duct-manipulated (sham operated; SO) rats. Impaired indexes of basal cardiac contractility were observed in the BDL pithed rats and isolated working hearts. In these two preparations, responsiveness to norepinephrine and the beta-adrenoceptor agonists, isoproterenol and dobutamine, was unaffected by bile duct ligation. The affinity and number of cardiac beta-adrenoceptors in membranes from the hearts of SO and BDL rats were not significantly different from each other. These experiments have established for the first time that the 3-day BDL rat has a cardiac myopathy associated with intact responsiveness to beta-adrenoceptor agonists, a normal unchanged affinity and number of cardiac beta-adrenoceptors.

Adrenergic beta-Agonists↗
PubMed1993

Hypokalemic flaccid paralysis as the presenting symptom of autoimmune interstitial nephropathy.

We describe a patient who presented dramatically with life-threatening hypokalemic flaccid paralysis. Following resuscitation, extensive investigation showed that the patient had lupus erythematosus (SLE) and Sjogren's syndrome (SS) of which she was unaware. A search for the cause of the profound hypokalemia led to the finding of obligatory renal potassium wasting due to distal renal tubular acidosis (RTA), secretory type. The acid base status of the patient showed hyperchloremic metabolic acidosis compatible with distal renal tubular acidosis. Our case is a further proof that patients with "overlap syndrome" (SLE-SS) may have RTA, which may lead to life-threatening hypokalemia. Others have shown that the SLE-SS complex may occasionally be complicated by hyperkalemia. Thus, an autoimmune disease that is relatively common may present with devastating electrolyte abnormalities.

Adult↗
PubMed1993

Acute renal failure in casualties of mass disasters.

Human-made and seismic catastrophes continue to extract a heavy toll in lives. Many survivors with extensive muscle injury succumb to preventable causes such as shock, extreme hyperkalemia or acute renal failure (ARF). Others may lose limbs because of the compartment syndrome. Early treatment of such casualties, starting in the field, may increase salvage of lives and limbs, and prevent ARF. The treatment consists of aggressive volume and bicarbonate replacement followed by forced solute alkaline diuresis. If myoglobinuric ARF has occurred, solute load should not be given, and regular hemodialysis (HD) is indicated. If mass casualties have occurred in remote regions and HD cannot be immediately provided, continuous arteriovenous hemofiltration (CAVH) may temporarily substitute for HD. CAVH has the distinct advantage of simplicity, and does not require electricity, pumps or delivery systems. It is effective in eliminating potassium and relieving circulatory congestion without causing hypotension.

Acute Kidney Injury↗
PubMed1992

Effect of hypertonicity on contractility of isolated working rat left ventricle.

OBJECTIVE: The aim was to evaluate the effect of hypertonic perfusate on isolated left ventricular mechanical and energetic characteristics. METHODS: An isolated working rat heart model was perfused with a hyponatraemic Krebs-Heinseleit bicarbonate buffer (240 mOsmol.litre-1). To this buffer was added increasing amounts of mannitol to achieve 280, 320, and 360 mOsmol.litre-1 perfusates. RESULTS: Left ventricular peak pressure, maximum time derivative of left ventricular pressure (dP/dtmax), and end systolic pressure were all increased to a maximum value at 280 or 320 mOsmol.litre-1 perfusate tonicity. A similar response was evident with cardiac output, which changed from 33.7(SEM 0.6) to 43.5(0.8) ml.min-1 following changing the perfusate tonicity from 240 to 280 mOsmol.litre-1 (p less than or equal to 0.003). However, increasing perfusate tonicity further decreased cardiac output to 36.5(1.3) ml.min-1 at 360 mOsmol.litre-1. Maximal left ventricular elastance remained unchanged during perfusion with increasing perfusate tonicities. CONCLUSIONS: Changing perfusate osmolality using mannitol has a positive inotropic effect at low osmolalities and a negative inotropic effect at perfusate osmolality greater than 320 mOsm.litre-1.

Animals↗
PubMed1992

Muscle microcirculatory impairment following acute compartment syndrome in the dog.

Visualization of the intramuscular microcirculation during and after compartmental syndrome was studied by microangiograms and histologic cross sections. A marked reduction in the circulation of the endomysial capillary network was found during compartment tamponade, whereas the perimysium arteriolar system was patent. Revascularization took place by formation of distorted blood vessels accompanied by intramuscular hematomas in muscles 7 and 14 days after the compartment insult. The cross sections show massive fibroblastic activity around blood vessels that caused concealed intramuscular pressure-ischemic contracture resulting in the foci of myofibrillar necrosis seen within normal muscle tissue. The muscle located in the tamponaded compartment profusely bleeds when it is touched, even though its viability is in doubt. The explanation for this clinical observation might be the abnormal intramuscular revascularization that was found in this work.

Acute Disease↗
PubMed1992

Sodium modulates inotropic response to hyperosmolarity in isolated working rat heart.

The present study was designed to examine the effects of acute changes in perfusate Na+ concentrations and osmolarities on left ventricular (LV) mechanics in the isolated working rat heart model. Specifically, we separated the effect of isosmotic perfusates with different Na+ concentrations on LV mechanics. After a control period during which the hearts were perfused in a working mode with a control solution of Krebs-Henseleit bicarbonate buffer (Na+ of 136 meq/l, Ca2+ of 2.6 mM, and osmolarity of 300 mosM), the hearts were subjected to different perfusates (Na+ of 96-156 meq/l and osmolarity of 240-380 mosM, using different mannitol concentrations) in a semirandom order. Peak LV pressure (PLVP), maximal time derivative of LV pressure (dP/dtmax), and cardiac output (CO) were recorded. Increasing Na+ concentrations from 96 to 156 meq/l, using isosmotic perfusates, decreased PLVP, dP/dtmax, and CO in a dose-dependent manner. The dose-dependent behavior was evident for tonicities of 240, 280, 320, and 360 but not for 380 mosM. Increasing Na+ concentration from 96 to 136 meq/l at constant perfusate tonicity (320 mosM) decreased dP/dtmax from 6,753 +/- 133 to 5,602 +/- 418 mmHg/s (P < 0.001). Rearranging the same results to examine the effect of perfusate tonicity with iso-Na+ concentration demonstrated that increasing perfusate osmolarity had a dose-dependent effect on PLVP, dP/dtmax, and CO. At a constant Na+ concentration of 116 meq/l, increasing perfusate osmolarity from 240 to 320 mosM increased dP/dtmax from 6,116 +/- 132 to 7,274 +/- 594 mmHg/s (P < 0.01). Further increase in perfusate tonicity to 380 mosM decreased dP/dtmax to 2,338 +/- 398 mmHg/s (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effect of atrial natriuretic factor on renal cGMP production in rats with adriamycin-induced nephrotic syndrome.

Adriamycin-induced nephrotic syndrome in the rat is associated with a blunted natriuretic response to infusion of atrial natriuretic factor. To study the mechanism of renal hyporesponsiveness to the peptide in rats with experimental nephrosis, we evaluated the effects of the hormone on renal production of cGMP, the second messenger of the hormone. Baseline GFR and sodium excretion were lower in nephrotic as compared with normal controls. Infusion of synthetic rat atrial natriuretic factor (10 micrograms/kg/h) increased fractional sodium excretion by 7.3 +/- 2.4% in control rats but only by 1.4 +/- 0.5% in adriamycin-treated rats (P less than 0.05). However, the increments in urinary nucleotide excretion rate (UcGMP x V/GFR), in response to atrial natriuretic factor infusion, were comparable in control and nephrotic rats (control, 114.7 +/- 16.1 pmol/mL; adriamycin, 95.5 +/- 12.0 pmol/mL; P was not significant). The in vitro generation of cGMP in response to incremental doses of the hormone (10(-11) to 10(-6) M + 1 mM 3-isobutyl methyl xanthine) was of similar magnitude in isolated glomeruli derived from control (2.4 +/- 0.25 to 9.1 +/- 1.0 pmol/mg of protein) and nephrotic rats (2.9 +/- 0.2 to 10.3 +/- 1.0 pmol/mg of protein) and was not impaired in suspensions of medullary tissue derived from nephrotic rats (control, 8.4 +/- 0.6 to 14.2 +/- 1.2 pmol/mg of protein; adriamycin, 7.3 +/- 0.7 to 22.0 +/- 2.4 pmol/mg of protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Hypertonic mannitol ameliorates intracompartmental tamponade in model compartment syndrome in the dog.

Acute compartment syndrome (ACS) is a devastating complication of rhabdomyolysis caused by muscle tamponade secondary to increased intracompartmental pressure (Pi). ACS requires emergency surgical decompression when Pi greater than 30 mmHg (normal less than 4.0 mmHg) and clinical signs exist. The present study was undertaken to examine whether mannitol which has been used extensively for prevention of acute renal failure in rhabdomyiolysis may also improve muscular hemodynamics in ACS. ACS was produced in dogs by injecting dog plasma into the anterolateral compartment of the hind limb. The Pi was directly monitored. Control dogs received saline, whereas experimental dogs received intravenously 20% mannitol (0.15 ml/min/kg) over a period of 1 h. The initial Pi was set arbitrarily at 100 mm Hg. Following the establishment of ACS, the spontaneous mean decrease in Pi in the control group was 40% of initial value over 60 min (n = 5) versus a decrease of 65%/60 min in the experimental (mannitol) group (n = 7, p less than 0.01). The net mean decompressive effect of mannitol treatments was approximately 28 mm Hg (mean control Pi minus mean experimental Pi at time 60 min). Extrapolated to man with ACS, such a decrease in Pi induced by mannitol theoretically could relieve compartmental tamponade noninvasively.

Angiography↗
PubMed1991

Acid-base balance and acute renal failure.

In several models of acute renal failure (ARF) in animals, acidosis has been found to worsen the renal failure, whereas alkalosis may ameliorate it. Most evidence points to a reduction in the degree of tubular obstruction by casts as the explanation for the beneficial effects of bicarbonate administration. However, alkalinization of the urine is effective only in some experimental conditions but not in others. The reason for these differences is not known but may relate to the nature of the obstructing casts. Alkalinization of the urine could decrease cast formation in Bence-Jones protein and hemoglobinuric ARF by increasing the negative charge on these molecules, thereby diminishing precipitation with anionic Tamm-Horsfall protein. In contrast, release of tubular cell contents into the urine, as occurs in renal ischemia, could lead to complex casts not responsive to alterations in urine pH. In aminoglycoside ARF, the beneficial effects of urine alkalinization may be due primarily to reduced uptake of the antibiotic by tubular epithelium, resulting in less cellular damage. Because tubular obstruction reduces net filtration pressure, new approaches to therapy which include efforts to raise net glomerular filtration pressure may improve the therapeutic efficacy of alkali administration.

Acid-Base Imbalance↗
PubMed1990

[Crush syndrome].

Explore the source record for details and available documents.

Crush Syndrome↗