Effect of ureteral excision on inner medullary solute concentration in rats.

To elucidate the role of the ureter in urinary concentration we studied the effect of partial and complete ureteral excision on urinary osmolality and papillary interstitial osmolality and on sodium, potassium, and urea concentrations in the antidiuretic rat. Urine and descending vasa recta (DVR) plasma samples were obtained by micropuncture of the left renal papilla before (period 1) and 45 min after (period 2) complete (group 1, n = 10 rats) or partial (group 2, n = 10 rats) ureteral excision. Urine osmolality fell from 2,063 +/- 156 (mean +/- SE) to 736 +/- 116 mosmol/kgH2O after complete ureteral excision (P less than 0.

Treatment outcome in low back pain patients: do compensation benefits make a difference?

Some evidence suggests that chronic pain patients who receive worker's compensation benefits have a tendency to exaggerate their symptoms and not benefit from treatment. This study compared 110 male chronic low back pain patients receiving either no compensation, time-limited compensation, or unlimited compensation on pretreatment and follow-up variables. The patients who received unlimited compensation tended to have a higher percentage of physician-rated symptom dramatization, to have more pain behavior, and to use more medication than the no-compensation and time-limited compensation patients.

Effect of long-term, alternate day feeding on renal function in aging conscious rats.

To examine the renal effects of lifelong intermittent feeding, we performed clearance and pathologic studies in 86 week old, awake male Sprague-Dawley rats fed on alternate days (N = 9) or ad libitum (N = 8) since the age of four weeks. Alternate day-fed rats were studied on both feeding and fasting days, and the values averaged. In the alternate day group the clearances of inulin (Cinulin) and PAH (CPAH), factored by body wt, were higher by 23% and 27%, respectively (P less than 0.

Urea flux in the ureter.

It has been hypothesized that urea from the final urine is recycled into the renal papilla through the pelvic epithelium. To test this hypothesis, samples of urine were collected by micropuncture proximally and distally through the intact, contracting ureter of the anesthetized rat. In 12 rats, in which urine flow was 5.

Course and pathogenesis of postischemic acute renal failure in the rat.

The effect of 45-min clamping of the renal artery was studied in the conscious uninephrectomized rat to reproduce the syndrome of hemodynamically mediated acute renal failure in humans after a single ischemic insult. Twenty-four hours after ischemia, creatinine clearance was reduced by 90%, whereas fractional excretion of sodium was markedly increased; over the subsequent 5 days, both values returned to normal. The animals were nonoliguric.

Empirically derived Symptom Checklist 90 subgroups of chronic pain patients: a cluster analysis.

Four hundred fifty-three chronic pain patients completed a Symptom Checklist 90 (SCL-90) and a comprehensive pain evaluation questionnaire. All patients were evaluated by a physician and rated on degree of pain pathology and pain behavior. The SCL-90 data were analyzed using two clustering procedures and replicated over two similar samples.

Micropuncture study of the effect of ANP on the papillary collecting duct in the rat.

Micropuncture collections were obtained from the terminal collecting duct (CD) at base and tip of the renal papilla of the rat. Group 1 was studied before and during infusion with atrial natriuretic peptide (ANP), group 2 was administered the vehicle only, and group 3 received acetazolamide to increase sodium delivery to the base to a similar extent as after ANP. ANP caused a decrease in blood pressure, a slight increase in GFR, natriuresis, and diuresis.

Anxiety and postoperative recovery in ambulatory surgery patients.

There has been a growing trend toward one-day ambulatory surgery. Unfortunately, there has been little research evaluating how patients recover at home after one-day surgery. This study examined the relationship between preoperative anxiety and postoperative recovery in ambulatory surgery patients.

The influence of problems with concentration and memory on emotional distress and daily activities in chronic pain patients.

This study examined concentration and memory problems in chronic pain patients as they related to emotional distress and interference with daily activity. Three hundred and sixty-three chronic pain patients were divided into two groups based on how much they expressed difficulty in concentrating and remembering things. Each patient was given a physical examination and completed a pain evaluation questionnaire and an SCL-90.

Effects of time-limited vs unlimited compensation on pain behavior and treatment outcome in low back pain patients.

A common theme in the pain literature is that worker's compensation reinforces pain behavior and adversely influences treatment outcome of chronic pain patients. This study compared 110 chronic low back pain males divided into three groups: 44 receiving no compensation, 27 receiving time-limited worker's compensation, and 39 receiving unlimited social security disability benefits. All patients participated in a multimodal treatment program (e.

Effect of adrenalectomy on transport in the rat medullary thick ascending limb.

Previous studies in adrenalectomized (Adx) rats suggest that aldosterone may regulate ion transport in the ascending portion of Helen's loop. In order to examine directly the effect of adrenalectomy on transport, medullary thick ascending limb (Mtal) segments were isolated from Adx, Adx replaced with aldosterone (Adx + Ald, 0.5 micrograms X 100 g X body wt X d), and control Sprague-Dawley rats.

Effect of V2-receptor-mediated changes on inner medullary blood flow induced by AVP.

We have previously shown that arginine vasopressin (AVP) in physiological amounts reduces inner medullary blood flow and that the mechanism of this decrease is at least in part mediated by the vasopressor (V1-receptor) action of AVP. To determine whether the antidiuretic action of AVP (V2-receptor) also contributes to the reduction in inner medullary blood flow, we determined capillary blood flow (QVR) in individual descending vasa recta (DVR) and ascending vasa recta (AVR) using fluorescence videomicroscopy in the exposed renal papilla of the anesthetized rat. Three groups of chronically water-diuretic rats were studied in three consecutive periods: control (period 1), experimental (period 2), and recovery (period 3).

Effect of atrial natriuretic peptide on vasa recta blood flow in the rat.

To determine whether synthetic atrial natriuretic peptide (ANP) increases renal medullary blood flow and if so whether the increase mediates the diuresis and natriuresis induced by ANP, inner medullary vasa recta blood flow in the exposed left renal papilla of anesthetized Munich Wistar rats weighing between 102 and 161 g was measured by fluorescence videomicroscopy. The rats were maintained in a euvolemic state by the infusion of albumin. Synthetic ANP (Auriculin B) was administered intravenously as 2.

Psychogenic factors in predicting survival of breast cancer patients.

Considerable controversy and contradictory data exist about the notion that psychosocial factors can predict longevity in cancer patients. This study further addresses that issue by eliminating some of the methodological weaknesses of prior studies and focusing on a more tightly defined patient population. Forty-nine female metastatic breast cancer patients were given a variety of psychological tests.

The medullary microcirculation.

Like other regional circulations, the medullary circulation supplies oxygen and other primary substrates to the medulla and removes carbon dioxide and other waste metabolites. It also acts as a countercurrent exchanger and simultaneously removes water reabsorbed from the renal tubule to preserve mass balance. Our present understanding of how the medulla serves both these functions at the same time is illustrated in Figure 3.

Short and long loop nephrons.

The explanation for the necessity to have both short and long loop nephrons for urinary concentration is unknown but may represent nature's resolution of conflicting ideal conditions for maximum urinary concentration. Ideally, one would like the thick ascending limb to extend throughout the entire medulla to the papillary tip and be supplied by a blood flow vigorous enough to provide oxygen and remove waste products as rapidly as needed. One would also like to have a progressively smaller volume of tissue to be concentrated toward the papillary tip to lessen the osmotic work required and a highly efficient vascular exchange system to sequester the medullary interstitial solute effectively.

Use of sensory descriptors in assessing chronic pain patients.

The present study examined the use of sensory descriptors in assessing chronic pain patients in a multidisciplinary treatment center. Three hundred and eighty-eight chronic pain patients were divided into two groups based on the number of pain sensations which they chose to depict their pain. The results indicated that patients who used numerous sensory descriptors experienced more physical interference and emotional distress and were at greater risk for treatment failure than those patients who used only one descriptor.

The shape of renal vasa recta capillaries and its effect on calculation of single capillary blood flow.

Previous studies of the renal papilla of the rat have suggested that the vasa recta capillaries can be well approximated by elliptical cylinders (C. Holliger, K. V.

Cooperation with treatment in adolescent cancer patients.

Twenty-seven adolescent cancer patients were rated by two pediatric oncology nurses using a ten-item cooperation questionnaire. Cooperation scores were compared with patient ratings of self-image, perception of cancer, health locus of control, and knowledge of cancer. Although all patients were generally cooperative, younger adolescents appeared to be more cooperative than older adolescents.