Cost containment and competition: rational or rationed health care?
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Cost Control↗
Biomedical subjects
R J Anderson
Publications and source records attributed to R J Anderson.
Severity of illness and DRG reimbursement.
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Diagnosis-Related Groups↗
Dental caries experience in Ceredigion, Wales, in 1973 and 1983 with special reference to environmental lead.
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Child↗
Postoperative hyponatremia. A prospective study.
In the present study, we found that at least 4.4% of 1,088 prospectively studied patients developed postoperative hyponatremia (plasma sodium concentration less than 130 mEq/L). Most patients (42%) were normovolemic. Edematous states (21%), hyperglycemia (21%), volume depletion (8%), and renal failure (8%), however, were also common settings of postoperative hyponatremia. Plasma arginine vasopressin was present in all patients in whom it was measured and 94% of the patients were receiving hypotonic fluid at the time of development of hyponatremia. Hyponatremia was not associated with significant neurologic deterioration in the 48 postoperative patients in the present study. In eight patients, however, the positive water balance that resulted in hyponatremia was associated with development of pulmonary vascular congestion. We conclude that hyponatremia commonly occurs following all types of surgical procedures and is due to hypotonic fluid administration in the presence of nonosmotic secretion of arginine vasopressin.
Adult↗
Autosomal dominant retinitis pigmentosa. A method of classification.
Four types of autosomal dominant retinitis pigmentosa (RP) were discernible in 84 patients by clinical, electrophysiologic, and psychophysical criteria. Type 1 patients showed diffuse fundus pigmentary changes and nondetectable electroretinographic (ERG) cone and rod functions. Both type 2 and type 3 patients showed fundus pigmentary changes more apparent within the inferior retina. Type 2 patients showed marked loss in rod ERG function, with prolonged cone implicit times, whereas type 3 patients showed substantial rod function and normal cone implicit times. Type 4 patients had a funduscopically and functionally "delimited" disease, with substantial cone and rod ERG amplitudes and normal implicit times. The classification of dominantly inherited RP is important for studies of natural history in disease progression, for patient counseling, and for various laboratory investigations of patients with RP in which patient homogeneity should be maximized.
Adolescent↗
Effects of alcohol and other drugs on traumatized patients.
During a six-month period, blood was drawn from 615 traumatized patients for alcohol determination and general toxicology screen. The patients were divided into four groups: alcohol only, other drugs only, alcohol and other drugs, and no alcohol or other drugs. Each group was analyzed for severity of injury, length of hospitalization, complications, and mortality. In 362 patients (58.9%) we found alcohol in the blood; 74% had alcohol levels greater than 100 mg/dL. Twenty patients (3.3%) had other drugs, while 34 patients (5.5%) had both alcohol and other drugs. There were no differences between the groups except that the patients with drugs only had a significantly higher incidence of shock, severity of injury, and mortality.
Accidents, Traffic↗
Electrophysiologic changes in peripheral nerve following repeated exposure to organophosphorus agents.
The purpose of this study was to examine the electrophysiologic changes which occur following repeated exposure to potent organophosphorus agents. The results show that DFP and soman each initially increase rat sciatic nerve conduction and reduce refractoriness. Continued exposure had a diminished effect with nerve excitability eventually returning to control. During recovery, the nerve membrane responsiveness to potassium-induced depolarization significantly changed in a manner which would indicate either decreased Na, K-ATPase activity or decreased potassium ion transmembrane flux. The data suggest that compensatory changes occur in rat nerve in response to organophosphorus exposure, and further, that these compensatory changes involve alteration in membrane ion fluxes.
Action Potentials↗
Purinergic regulation of basal and arginine vasopressin-stimulated hydraulic conductivity in rabbit cortical collecting tubule.
An extracellular adenosine responsive site that stimulates adenylate cyclase activity has been identified in several tissues. There is limited information on the presence and physiologic significance of adenosine receptors in well-defined segments of the mammalian nephron. We therefore examined the effect of adenosine and selected analogues on basal hydraulic conductivity in rabbit cortical collecting tubules (CCT) perfused in vitro. Adenosine and analogues with an intact ribose moiety produced a significant, sustained increase in hydraulic conductivity. No increase in hydraulic conductivity was seen in either time control CCT's or CCT's exposed to an adenosine analogue with an altered ribose moiety. These experiments are compatible with the presence of a functional adenosine receptor which requires an intact ribose moiety and acts to increase hydraulic conductivity in the mammalian CCT. An intracellular adenosine responsive site, termed the "P site," which inhibits adenylate cyclase activity, has also been described in several tissues. We therefore examined the effect of a P site agonist on hydraulic conductivity responses to arginine vasopressin, forskolin and cAMP. P site stimulation with 2'5' dideoxyadenosine inhibited the effect of AVP and of forskolin but not of cAMP to increase hydraulic conductivity. These results are compatible with a functional P site in the rabbit CCT which acts at the catalytic subunit of adenylate cyclase to inhibit hydraulic conductivity. Together, these results demonstrate purinergic modulation of basal and arginine vasopressin-stimulated water flux in the mammalian collecting tubule.
Adenosine↗
Sclerosing-cholangitis-like changes in pancreatic disease.
In a retrospective analysis of endoscopic cholangiograms in 66 patients with pancreatic disease we found sclerosing-cholangitis-like changes in 83% of cases. Excluding patients with intrapancreatic constriction of the distal common bile duct, 70% of patients with chronic pancreatitis, 60% with acute pancreatitis and 100% with pancreatic cancer had these abnormalities. The possible significance of these changes, which are unlikely to be secondary to pancreatic disease, are discussed with reference to the published literature on sclerosing cholangitis.
Adult↗
Evaluation of acute scrotum pain with testicular scanning.
Emergency room physicians frequently are faced with the evaluation of the patient with acute testicular pain. The rapid differentiation between testicular torsion and acute epididymitis is necessary although frequently difficult due to an atypical presentation. We describe four patients with testicular pain in whom testicular scanning provided useful adjunctive information regarding diagnosis. This technique clearly differentiates acute torsion, acute epididymitis, testicular rupture, and missed torsion with abscess formation, prompting appropriate therapy in each case. Testicular scanning provides a rapid, noninvasive method to assist in the evaluation of testicular pain.
Adolescent↗
Nonoliguric acute renal failure.
Oliguria has been considered a cardinal feature of acute renal failure. However, many recent reports indicate that acute renal failure usually occurs in the setting of well-maintained urine output. Moreover, the nonoliguric state may accompany acute renal failure due to pre- and post-renal azotemia and a variety of renal parenchymal disorders, as well as acute tubular necrosis. Most studies indicate that nonoliguric forms of acute renal failure are associated with less morbidity and mortality than oliguric acute renal failure. Uncontrolled studies also suggest that volume expansion, potent diuretic agents, and renal vasodilators can convert oliguric to nonoliguric acute tubular necrosis if administered early in the course of acute renal failure. However, prospective studies of early intervention in oliguric patients are needed.
Acute Kidney Injury↗
Selected health care maintenance policies in chronic dialysis centers.
Although a large number of patients are maintained on chronic dialysis, there is little information regarding the medical care rendered to these patients. We therefore obtained information on health care maintenance policies from 90 dialysis centers (8,104 patients) selected from each End-Stage Renal Disease (ESRD) Network. All centers except one obtained BUN, creatinine, electrolytes, calcium, and phosphorus at intervals of 1 month or less; 85% of centers obtained a multiple-test laboratory panel at monthly intervals. Annual physical examination, ECG, and chest x-ray were performed in 80% or more of the centers. Immunization policies varied with 88%, 64%, and 17% of centers offering influenza, pneumococcal, and hepatitis B vaccine, respectively. Patterns of surveillance for anemia, osteodystrophy, and hepatitis were variable. In view of the high frequency and cost of testing, prospective studies to determine optimal methods of health care maintenance in the chronic dialysis center are indicated.
Anemia↗
Modification of reserpine induced rigidity by dopaminergic and alpha-adrenergic drugs.
Previous studies have reported that a variety of drugs are effective in preventing reserpine-induced hypertonus, including dopamine agonists and alpha-adrenergic antagonists. The purpose of this study was to use a quantitative measure of hindlimb muscle tone to evaluate the relative efficacy of various drugs with known pharmacologic actions on dopaminergic and adrenergic receptors. The results show that adrenergic antagonists (yohimbine, thymoxamine, phentolamine, RS 21361) were the most effective in protecting against the effect of reserpine. Along with the dopamine precursor, 1-DOPA, these drugs were not only effective but also they produced no muscle relaxation in non-reserpinized rats. Although dopamine agonists (apomorphine, lisuride, bromocriptine) also protected against reserpine-induced rigidity, these drugs also produced muscle relaxation in non-reserpinized rats. A variety of drugs with alpha adrenergic agonist, beta adrenergic antagonist, dopamine antagonist and antihistamine activity did not alter the reserpine-induced rigidity despite generalized muscle relaxant effects with some of these. The results show that alpha adrenergic antagonists are the most selective agents in preventing reserpine-induced rigidity and suggest that alpha-2 receptors primarily mediate this effect.
Adrenergic alpha-Antagonists↗
Prevalence of posterior subcapsular lens opacities in patients with retinitis pigmentosa.
We clinically evaluated 338 patients with various genetic types of retinitis pigmentosa (RP) for the presence of posterior subscapsular (PSC) lens opacities. Of these, 180 (53%) had PSC lens changes or were bilaterally aphakic. Patients with X-linked recessive RP showed a greater prevalence and patients with autosomal dominant RP a lesser prevalence of PSC lens changes compared with autosomal recessive or isolated cases.
Adolescent↗
Defined human renal tubular epithelia in culture: growth, characterization, and hormonal response.
Individually microdissected nephron segments of defined epithelial origin from human kidneys were cultured in vitro in the present studies. Nephron segments of proximal convoluted tubule, proximal straight tubule, cortical thick ascending limb of Henle, and cortical collecting tubule were grown in defined media. Each cell type retained differentiated characteristics as assessed by ultrastructural morphology, marker enzyme profiles, and adenylate cyclase response to selected hormones. These studies demonstrate the feasibility of using primary cultures of well-defined segments of the human nephron to study human renal tubular epithelia in vitro.
Adenylyl Cyclases↗
Uptake of taurocholate by freshly isolated hepatocytes from fetal and newborn rabbits.
During early postnatal maturation a significant increase in the rate constant of translocation (Michaelis-Menten constant; Km) for taurocholate uptake occurs in isolated rabbit hepatocytes. This age-dependent change is related to a decrease in the efficiency of uptake for taurocholate and is probably associated with changes in the receptor or its microenvironment within the plasma membrane. Cholic acid conjugates (taurocholic and glycocholic acids) are the predominant bile acids found in the premature and neonatal human. It is therefore of interest that in the fetal and neonatal rabbit we have found a developmentally dependent alteration of taurocholic acid transport.
Animals↗
Effects of vasopressin antagonist on vasopressin binding, adenylate cyclase activation, and water flux.
We studied the effect of an arginine vasopressin (AVP) analogue, (1-[beta-mercapto-beta, beta-cyclopentamethylenepropionic acid],2-O-ethyltyrosine, 4-valine)AVP(d[CH2]5Tyr[Et]VAVP), on the stimulation of adenylate cyclase by various hormones in the isolated nephron segments and 3H-AVP binding to renal papillary membranes from the rat. The net water flux across the renal cortical collecting tubules of the rabbit was also examined. We found that d(CH2)5Tyr(Et)VAVP significantly inhibited adenylate cyclase activation by AVP in cortical, medullary, and papillary collecting tubules and in the medullary thick ascending limb. In contrast, the AVP analogue did not alter the stimulation of adenylate cyclase by parathyroid hormone in the cortical thick ascending limb, by glucagon in the medullary thick ascending limb, and by calcitonin in cortical collecting tubules. In addition, d(CH2)5Tyr(Et)VAVP blocked [3H]AVP binding to renal papillary membranes. The enhanced net water transport induced by AVP in isolated, perfused rabbit cortical collecting tubules also was completely blocked by this AVP analogue. These results indicate that d(CH2)5Tyr(Et)VAVP specifically antagonizes the cellular action of AVP on the medullary thick ascending limb and on the cortical, medullary, and papillary collecting tubules. Evidence is also presented for competitive antagonism as the cellular mechanism of action.
3',5'-Cyclic-AMP Phosphodiesterases↗
Hyponatremia: a prospective analysis of its epidemiology and the pathogenetic role of vasopressin.
We prospectively evaluated the frequency, cause, and outcome of hyponatremia (plasma sodium concentration, less than 130 meq/L), as well as the hormonal response to this condition, in hospitalized patients. Daily incidence and prevalence of hyponatremia averaged 0.97% and 2.48%, respectively. Two thirds of all hyponatremia was hospital acquired. Normovolemic states (so-called syndrome of inappropriate secretion of antidiuretic hormone) were the most commonly seen clinical setting of hyponatremia. The fatality rate for hyponatremic patients was 60-fold that for patients without documented hyponatremia. Nonosmotic secretion of vasopressin was present in 97% of hyponatremic patients in whom it was sought. In edematous and hypovolemic patients, plasma hormonal responses (increases in plasma renin activity and aldosterone and norepinephrine levels) were compatible with baroreceptor-mediated release of vasopressin. Hyponatremia is a common hospital-acquired electrolyte disturbance that is an indicator of poor prognosis. Nonosmotic secretion of arginine vasopressin is a major pathogenetic factor in this electrolyte disturbance.
Adolescent↗