Spirituality and the nurse.
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Breast Neoplasms↗
Biomedical subjects
C Ott
Publications and source records attributed to C Ott.
Internet breast cancer related resources.
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Breast Neoplasms↗
Effect of luminal vasopressin on NaCl transport in the medullary thick ascending limb of the rat.
The aim of the present study was to determine whether vasopressin affects NaCl reabsorption in the medullary thick ascending limb of the loop of Henle when administered selectively to the luminal membrane. At 5 x 10(-6) M and 10(-8) M, luminal [Arg8]vasopressin significantly inhibited Cl- transport in the in vitro microperfused rat medullary thick ascending limb by 46.4 +/- 5.9% (P < 0.01) and 32.4 +/- 2.0% (P < 0.05) respectively. The response to 10(-8) M luminal [Arg8]vasopressin was completely blocked by the vasopressin V1 receptor antagonist [beta-mercapto-beta,beta-cyclopenta-methylenepropionyl1, O-Me-Tyr2,Arg8]vasopressin (10(-6) M), and was mimicked by the vasopressin V1 receptor agonist [Phe1, Ile5, Orn8]vasopressin (10(-8) M; delta -35.0 +/- 4.5%; P < 0.05). Luminal administration of the vasopressin V2 receptor agonist [deamino-Cys1, D-Arg8]vasopressin (5 x 10(-6) M) had no effect on transport. These data suggest that luminal vasopressin can inhibit NaCl transport in the medullary thick ascending limb of the rat via vasopressin V1 receptors.
Absorption↗
Mechanism of atrial natriuretic peptide release with increased inspiratory resistance.
Elevated plasma atrial natriuretic peptide (ANP) levels and concomitant increases in renal sodium and water excretion are often encountered in respiratory diseases associated with increased airway resistance such as obstructive sleep apnea. The present study utilized an anesthetized rat model to determine the principal mechanism(s) responsible for stimulation of ANP release in this clinical syndrome. A 10-minute increase in external resistive loading, which reduced peak tracheal pressure to -15 to -17 mm Hg produced a significant increase in both central venous pressure and right atrial transmural pressure. This maneuver subsequently resulted in significant transient increases in glomerular filtration rate; urine flow; urinary Na+, K+, and Cl- excretion; and urinary cyclic guanosine monophosphate (cGMP) excretion, which was taken as an index of increased circulating levels of ANP. Similar changes in renal function and cGMP excretion occurred when arterial PO2 was lowered to a degree equivalent to that seen with increased resistive loading. Lowering arterial PO2 also significantly increased mean central venous pressure and right atrial transmural pressure. Conversely, the resistive loading-induced changes in renal function and cGMP excretion did not occur when the reduction in arterial PO2 was prevented by breathing a high O2 gas mixture during the resistive loading. Additionally, O2 supplementation prevented the increases in both mean central venous pressure and right atrial transmural pressure caused by increased resistive loading. These data indicate that the elevated ANP release that results from an acute increase in external resistive loading is not caused by a decrease in intrathoracic pressure but rather suggest that the elevated ANP release is primarily caused by an increased right atrial transmural pressure resulting from hypoxia-induced pulmonary vasoconstriction.
Airway Resistance↗
Effect of bradykinin on NaCl transport in the medullary thick ascending limb of the rat.
The aim of the present study was to determine whether bradykinin affects NaCl reabsorption in the medullary thick ascending limb of the loop of Henle. At 10(-8) M, bradykinin significantly inhibited Cl- transport in the in vitro microperfused rat medullary thick ascending limb by 67% (P < 0.01). This inhibitory effect could be totally prevented by preincubating tubules with the bradykinin B2 receptor antagonist N alpha-adamantaneacetyl-D-Arg-[Hyp3,Thi5,8,D-Phe7]brady kinin (10(-6) M). In contrast, the bradykinin B1 receptor agonist des-Arg9 bradykinin (10(-6) M) had no effect on Cl- transport. Bradykinin caused transient increases in intracellular Ca2+ concentration, which could be blocked by the bradykinin B2 receptor antagonist, but could not be reproduced with the bradykinin B1 receptor agonist. These data suggest that the natriuretic and diuretic effect of bradykinin in vivo is due, at least in part, to a bradykinin B2 receptor-mediated inhibition of NaCl reabsorption in the medullary thick ascending limb of the loop of Henle.
Animals↗
[Gynecological-obstetrical psychosomatics (theoretical and practical considerations on education)].
Theoretical concepts of psychosomatics are presented in the first section with special emphasis on psychosomatics in gynecology and obstetrics. In the second part, some examples are presented to demonstrate the realization of psychosomatic thinking in the setting of a university clinic. Arising difficulties are discussed.
Education, Medical, Continuing↗
Heat stress does not modify lactate exchange and removal abilities during recovery from short exercise.
Arterial and femoral venous lactate concentrations were measured before, during, and after short intermittent exercise (55-118% of maximal O2 consumption) in thermoneutral (N, 25 degrees C, 10.5 Torr) and hot (H, 45 degrees C, 17.5 Torr) conditions. The thermal load induced significantly higher heart rate and rectal temperature in H relative to N. All the arterial lactate (La) recovery curves were fitted to an equation containing two exponential time functions of the form La(t) = La(0) + A1a(1 - e-gamma 1at) + A2a(1 - e-gamma 2at) where the velocity constants gamma 1a and gamma 2a are the body's overall ability to exchange and remove lactate after exercise, respectively, and t is time. There was no significant difference in these constants, regardless of thermal conditions. The arterial lactate concentration at the end of exercise, the peak lactate concentration during recovery, the amplitudes A1a and A2a of the biexponential function, and the arteriofemoral venous lactate concentration difference during recovery were not significantly different in H relative to N. However, measured and computed arterial lactate concentrations during recovery, especially at the end of the tests, were higher in H (P < 0.04). The more elevated lactate concentrations in H at rest at the end of recovery denote a higher basal lactate production, and they were not due to muscle hypoxia.
Adult↗
Glossodynia--psychodynamic basis and results of psychopathometric investigations.
Between 1985 and 1988, 131 patients suffering from glossodynia were submitted to a careful examination that included a neurological work-up, a detailed psychiatric interview and a number of psychological tests. Particular attention was paid to psychosomatic and psychopathologic disorders. The average age of the patients was 55 yr, and 73% of them were female. In 40% of patients, the psychiatric interview revealed no psychopathological findings, while in most of them, a psychiatrically relevant disorder, usually depression, was found. All patients had an unremarkable neurological status, and the EEG's showed no pathological changes. Psychodynamic considerations in conjunction with the elevated scores for depressive mood, anxiety and tension suggest that glossodynia is an expression of a psychosomatic disorder.
Adult↗
Use of pentoxifylline as an inhibitor of free radical generation in peripheral vascular disease. Results of a double-blind placebo-controlled study.
The effects of an infusion of pentoxifylline 1 g as an inhibitor of free radical generation have been determined in a double-blind placebo-controlled study. Leucocyte-derived free radical generation (by the superoxide dismutase-inhibitable reduction of ferricytochrome), the release of reactive oxygen metabolites (as plasma oxidant activity), unfractionated leucocyte and erythrocyte filterability rates (using a constant-flow positive-pressure system), plasma viscosity, and plasma fibrinogen concentration have been measured in two matched groups of 10 patients with Stage II peripheral vascular disease, before and after treatment. Transcutaneous oxygen pressure (PtcO2) during treadmill exercise to stress leg circulation was also measured. Leucocyte-derived free radicals were generated during peripheral ischaemia. Pentoxifylline inhibited their generation, blocked the release of reactive oxygen metabolites, and reduced impairment of the filterability rate of unfractionated leucocytes. The improvements were accompanied by significant shortening of the half-time of recovery of transcutaneous oxygen pressure, indicating that ischaemic damage had been contained.
Cross-Sectional Studies↗
Blood rheology during bacterial infection in the elderly and early middle-aged.
The aim of this study was to ascertain if the hemorheological profiles in 35 elderly and 20 young to middle-aged patients returned to normal after bacterial infection. Erythrocyte sedimentation rates, fibrinogen levels, plasma viscosity, hematocrit, white blood cell count and filterability rates (through 5 mu diameter pore filters, using a low shear positive pressure Nuclepore filtration system) of red blood cells and unfractionated leucocytes were determined at the onset of acute bacterial infection, after 3 weeks at full clinical recovery, and again 2 weeks later at the end of convalescence. Our data confirm that rheological impairments exist at the onset of bacterial infection, and persist up to clinical recovery. At the end of convalescence the unfractionated leucocyte filterability rate was still significantly higher in the elderly patients, compared not only to our normal standard, but also to average values in the younger group.
Adult↗
Are leucocyte-derived free radicals involved in ischaemia in human legs?
Leucocyte-derived free radicals were monitored in 30 stage II peripheral vascular disease (PVD) patients in an open placebo-controlled study. Linked to a transcutaneous oxygen pressure (TcPO2) monitor, they performed two consecutive standard treadmill tests (5 min, 2 km h-1, 12% slope) before and after 15-days treatment with placebo or a leucocyte-derived free radical scavenger (Piroxicam, 20 mg day-1), the second test being carried out at the TcPO2 half-recovery time. Blood samples were collected at baseline, at the maximum walking times and the TcPO2 half recovery times. The total and differential leucocyte counts, the percentage of cells with pseudopodia or cytoplasmatic irregularities, the filterability rates (using a positive pressure Nuclepore filter system) of the main leucocyte subfractions and plasma oxidant activity were monitored. Compared with values before treatment and with the placebo-treated group Piroxicam therapy significantly (P less than 0.001) reduced the final half-recovery time, the percentage of cells with pseudopodia and the level of plasma oxidant activity (P less than 0.01) and kept the granulocyte filterability rate stable, showing leucocyte-derived free radicals are involved in peripheral ischaemia.
Exercise↗
Bacterial infection and peripheral vascular disease.
Whole blood filterability was monitored in 16 nondiabetic peripheral vascular disease (PVD) patients within forty-eight hours of onset of bacterial infection, after ten to seventeen days antibiotic therapy and again, ten days later, after convalescence. The whole blood filterability rate was constantly disturbed before infection in these patients; the impairment worsened significantly (as was expected during infection), but after convalescence the whole blood filterability rate did not return to preinfection levels. This further significant impairment in whole blood filterability was inversely correlated with a reduction in the patients' pain-free walking time as determined by a standard treadmell test performed after convalescence and compared with their average times before infection.
Bacterial Infections↗
Impaired cyclic AMP generation in outer medullary tubules of gentamicin-treated rats.
We have examined the effects of chronic gentamicin treatment on arginine8-vasopressin (AVP)-dependent cyclic AMP (cAMP) metabolism in rat medullary collecting tubules (oMCT) and medullary thick ascending limbs of Henle's loop (mTALH). Gentamicin attenuated AVP-stimulated cAMP accumulation to a greater extent in the mTALH (delta -51%) than in the oMCT (delta -25%). The mechanism of attenuation differed between segments, and could not be attributed to either direct inhibition of adenylate cyclase activity nor direct potentiation of cAMP-phosphodiesterase activity. These data suggest that the gentamicin-induced decrease in renal concentrating ability may be due at least in part to reduced AVP-dependent cAMP accumulation in the oMCT and mTALH.
1-Methyl-3-isobutylxanthine↗
Blood rheology during induced ischaemia of the lower limbs.
The filterability rate of whole blood, the red and white blood cell sub-populations, and the erythrocyte and leucocyte count variations were studied during exercise in 20 male non-diabetic smokers, all with Stage II peripheral vascular disease (PVD), and 20 matched controls. A controlled ischaemia was induced using treadmill exercise. Blood samples were taken at rest, at the onset of calf pain and at haemodynamic recovery from peak exercise. Leucocytes were counted, separated using Ficoll-Hypaque into their sub-populations by centrifugation, and adherence to Petri dishes, re-suspended in buffer and filtered through 5 micron pore diameter filters. Whole blood filterability and the leucocyte count were significantly increased at the onset of calf pain. A significant increase was observed in the filterability of the monocyte sub-fraction and this persisted throughout the recovery period.
Blood Viscosity↗
Blood lactate during constant-load exercise at aerobic and anaerobic thresholds.
Venous blood lactate concentrations [1ab] were measured every 30 s in five athletes performing prolonged exercise at three constant intensities: the aerobic threshold (Thaer), the anaerobic threshold (Than) and at a work rate (IWR) intermediate between Thaer and Than. Measurements of oxygen consumption (VO2) and heart rate (HR) were made every min. Most of the subjects maintained constant intensity exercise for 45 min at Thaer and IWR, but at Than none could exercise for more than 30 min. Relationships between variations in [1ab] and concomitant changes in VO2 or HR were not statistically significant. Depending on the exercise intensity (Thaer, IWR, or Than) several different patterns of change in [1ab] have been identified. Subjects did not necessarily show the same pattern at comparable exercise intensities. Averaging [1ab] as a function of relative exercise intensity masked spatial and temporal characteristics of individual curves so that a common pattern could not be discerned at any of the three exercise levels studied. The differences among the subjects are better described on individual [1ab] curves when sampling has been made at time intervals sufficiently small to resolve individual characteristics.
Aerobiosis↗
Comparative lactate kinetics after short and prolonged submaximal exercise.
Arterial blood lactate concentrations were determined in two groups of eleven males before, during and after near 2 W.kg body mass-1 bicycle exercise. One group of subjects cycled for 3 min, whereas the second group exercised for 60 min. All the lactate curves during recovery could be fitted to a bi-exponential time function consisting of a rapidly increasing and a slowly decreasing component. This typical evolution pattern indicates that the two-compartment model which has been proposed to represent the movements of lactate after short exercise applies also to recovery from prolonged exercise. Lengthening exercise duration decreased (respectively 10% and 28%) the value of both velocity constants of the fits to the lactate recovery curves, with the difference (28%) being statistically significant for the velocity constant describing the slowly decreasing part of the curves. This result indicates that extending exercise from 3 to 60 min impairs the ability to remove lactate after the exercise.
Adult↗
Lactate removal ability and graded exercise in humans.
Venous lactate concentrations of nine athletes were recorded every 5 s before, during, and after graded exercise beginning at a work rate of 0 W with an increase of 50 W every 4th min. The continuous model proposed by Hughson et al. (J. Appl. Physiol. 62: 1975-1981, 1987) was well fitted with the individual blood lactate concentration vs. work rate curves obtained during exercise. Time courses of lactate concentrations during recovery were accurately described by a sum of two exponential functions. Significant direct linear relationships were found between the velocity constant (gamma 2 nu) of the slowly decreasing exponential term of the recovery curves and the times into the exercise when a lactate concentration of 2.5 mmol/l was reached. There was a significant inverse correlation between gamma 2 nu and the rate of lactate increase during the last step of the exercise. In terms of the functional meaning given to gamma 2 nu, these relationships indicate that the shift to higher work rates of the increase of the blood lactate concentration during graded exercise in fit or trained athletes, when compared with less fit or untrained ones, is associated with a higher ability to remove lactate during the recovery. The results suggest that the lactate removal ability plays an important role in the evolution pattern of blood lactate concentrations during graded exercise.
Adolescent↗
Reactive oxygen metabolites in peripheral arterial occlusive disease.
Plasma oxidant activity (marker of reactive oxygen metabolites) and the unfractionated leucocyte filterability rate (determined through 5 micron pore diameter Nuclepore filters, using a positive pressure system) were monitored in 15 stage II peripheral vascular disease (PVD) patients before and after ischaemia was induced by treadmill exercise (12 degrees slope/2 km/hour). Plasma oxidant activity increased (+ 115%) significantly (p less than 0.001) at the maximum walking time, correlating (r = 0.79) with a significant (p less than 0.001) impairment (+23%) in the unfractionated leucocyte filterability rate. At the transcutaneous oxygen pressure (tcPO2) half recovery time the plasma oxidant activity approached basal values but the unfractionated leucocyte filterability rate remained significantly (p less than 0.001) impaired (+16%). It returned to basal values at the full tcPO2 recovery time. These results show reactive oxygen metabolites are released during ischaemia of the lower limbs and are correlated with a significant impairment in the flow properties of leucocytes.
Arterial Occlusive Diseases↗