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Biomedical subjects

J Ladefoged

Publications and source records attributed to J Ladefoged.

At least 73 records · Page 4Linked to original sources
PubMed1986

An abnormal response of the adrenal cortex to insulin: glucose in essential hypertension.

This investigation demonstrates an abnormal response to the adrenal cortex to modulation of the potassium metabolism by an intravenous infusion of insulin-glucose in patients with essential hypertension. In response to insulin-glucose there was a transient decline of plasma aldosterone and plasma cortisol concentrations in control subjects with normal blood pressure, whereas a temporary increase of both hormones was found in patients with essential hypertension. Treatment with thiazide diuretics further magnified the different aldosterone response between the two groups. It is suggested that the abnormal response of patients with essential hypertension may be of significance to the understanding of the pathogenesis of this important disease.

Adrenal Cortex↗
PubMed1985

The immunosuppressive potency of various steroids on peripheral blood lymphocytes, T cells, NK and K cells.

The immunosuppressive effect of natural and synthetic steroids was tested in vitro on phytohemagglutinin (PHA) stimulated T lymphocytes and peripheral blood lymphocytes (PBL), as well as on NK and K cell activity. Three groups of steroids, significantly different in their immunosuppressive activity, were identified. Fluorohydrocortisone, and methylprednisolone were highly potent in suppressing PHA stimulation of T lymphocytes and PBL. Hydrocortisone was of intermediate potency, whereas cortisone, dihydrocortisol, and tetrahydrocortisol were of low potency. T lymphocytes were more sensitive to the suppressive effect of fluorohydrocortisone and methylprednisolone than were PBL cultures. NK and K cell activity was suppressed only by the high potency synthetic steroids and even then the suppression of K cell activity was not significant except at high in vitro steroid concentrations. The present findings support the conception that different lymphocyte subpopulations have different susceptibility to the effect of highly potent steroids. Thus, lymphocyte heterogeneity must be taken into account when the immunosuppressive potencies of different glucocorticoids are studied. Furthermore, the findings in different lymphocyte populations ranked the relative in vitro immunosuppressive potency of glucocorticoids different from the relative anti-inflammatory potencies reported in the literature.

Adult↗
PubMed1985

In vitro natural killer and killer cell functions in uremia.

In uremia, mitogen responses of lymphocytes are decreased as is their resistance to the immunosuppressive effect of steroids. We examined the functions of natural killer (NK) and killer (K) cells from uremic patients and their sensitivity to in vitro immunosuppression by methylprednisolone. NK- and K-cell activity was as high as that of control subjects, and remained so at different titrations of effector cells. The functions of NK and K cells from uremic patients tended to be more resistant to methylprednisolone than those of control NK and K cells. Thus, while uremia impairs T-cell functions and T-cell sensitivity to steroids in vitro, the cytotoxic effector cell functions which are not dependent on cell proliferation remain unaffected.

Adrenal Cortex Hormones↗
PubMed1985

Renal tubular acidosis secondary to jejunoileal bypass for morbid obesity.

Renal handling of acid and base was studied in patients with persistent metabolic acidosis 3-9 years after jejunoileal bypass for morbid obesity. Excretion of acid was studied before and after intravenous infusion of NH4Cl and excretion of bicarbonate after infusion of NaHCO3. Bypass patients showed impaired capacity for acidification of urine. The lowest urinary pH was 5.53 +/- 0.10 in 10 bypass patients and 4.76 +/- 0.06 in 6 controls. The corresponding values for standard bicarbonate in plasma were 15.0 +/- 0.3 mM and 15.8 +/- 0.3 mM. Glomerular filtration rate was identical in the two groups. Fractional loss of bicarbonate in urine was higher in controls than in bypass patients. The renal impairment is classified as distal renal tubular acidosis.

Acidosis, Renal Tubular↗
PubMed1985

Pain perception expressed by postoperative analgetica need in patients with nephropathia interstitialis chronica e phenacetin.

The consumption of narcotic analgesics was investigated after uncomplicated renoallotransplantation of 21 patients with nephropathia interstitialis chronica e phenacetin and in a control group (N = 21) with renal insufficiency of another origin. We find significantly greater consumption in the former group. The possibility of a previously existing increased pain sensibility in these patients as a disposing factor is discussed.

Adult↗
PubMed1985

Aldosterone response to modulation of potassium in patients on dialysis or with essential hypertension.

This investigation demonstrates in patients with essential hypertension an abnormal response of the adrenal glands to modulation of potassium metabolism by infusion of insulin-glucose. Similar results have been reported in anephric patients, while the inverse response of non-nephrectomised patients on dialysis corresponded to that of normal subjects. It is suggested that the abnormal response of patients with essential hypertension may be of importance to the understanding of the pathogenesis of this important disease.

Adult↗
PubMed1985

Clinical results and cyclosporine effect on prednisolone metabolism of cadaver kidney transplanted patients.

In the first randomised study of cyclosporine in Denmark 43 cadaveric kidney recipients were treated either with cyclosporine (Cys) and prednisone or azathioprine (Aza) and prednisone. The degradation of prednisolone was examined in 18 of these patients. The 12 month graft survival of the Cys group was not significantly greater than that of the Aza group (68% and 60%, respectively), but fewer rejection episodes occurred in the Cys group (p less than 0.05). The degradation of prednisolone was significantly decreased in the Cys group compared to the Aza group. Accordingly, plasma half-lives of prednisolone were increased in the Cys group compared with the Aza group. As a decreased degradation of prednisolone during Cys treatment may lead to increased steroid activity, we recommend that a reduction of the prednisone dosage during Cys treatment is safe.

Adult↗
PubMed1985

Sodium activity, sodium concentration, and osmolality in plasma in acute and chronic renal failure.

We compared the ionic activity of sodium, as measured with glass electrodes, with sodium concentration in 23 healthy persons, 15 persons with acute renal failure, and before and after dialysis in 46 patients with chronic renal failure. In healthy persons the mean (+/- SEM) sodium concentration was 139.1 +/- 0.6 mmol/L, whereas the ionic activity was equal to that of a 145.2 +/- 0.5 mmol/L solution of sodium chloride. Variation in the concentration of plasma protein was the most important factor influencing the sodium activity coefficient (the ratio between activity and concentration). The sodium activity coefficient in plasma water (corrected for the non-aqueous phase of the plasma) was fairly constant, being 96% of that in a 140 mmol/L solution of sodium chloride. Thus sodium binds to non-protein molecules and sodium ions interact with other substances in uremic plasma only to a very limited extent. The sum of the molar activities of sodium, potassium, urea, and creatinine was closely and linearly correlated with plasma osmolality, both before and after dialysis.

Acute Kidney Injury↗
PubMed1984

Therapeutic effect of exercise on hypertension.

Arterial blood pressure, total peripheral resistance (TPR), plasma catecholamine and other hormone concentrations were measured or estimated during, and 4 h following, a 20-min exercise test on the bicycle ergometer in 10 women with marginal (borderline) hypertension. Each woman served as her own control by repeating the whole procedure, except for the exercise test, on another day. Median and 80% range was used: M (0.8 R). Compared with the control, the exercise reduced the driving blood pressure from 103 (94-110) to 95 (80-100) mm Hg and the TPR from 1.13 (0.96-1.40) to 0.91 (0.79-1.11) PRUs - both reductions being statistically significant with two-sided P less than 0.05 for at least 4 h. - The reduced nervous and humoral sympathetic activity following aerobic exercise seems capable of explaining the low TPR, and the continuous rise in the muscular vasodilatator dopamine may be of importance.

Adult↗
PubMed1984

Intra-individual consistency of prednisolone kinetics during long-term prednisone treatment.

Eleven patients on long-term prednisone treatment were studied on two occasions separated by 45 to 325 days. In 10 patients the total body clearance of prednisolone only changed about 10%. In one case a 78.5% decrease was observed after stopping treatment with rifampicin and isoniazide. No association was found between the prednisone dose rate (mg/kg per month), patient age or mean endogenous plasma hydrocortisone level and prednisolone clearance/kg. The results indicate considerable intra-individual consistency of prednisolone kinetics if other conditions are not changed.

Adult↗
PubMed1984

Lack of effect of prenalterol on dialysis-associated hypotension.

Prenalterol, a cardio selective beta adrenergic receptor antagonist was given perorally in doses from 20-150 mg/day in three patients with dialysis associated hypotension. No effect on blood pressure was seen over several months during this treatment.

Adrenergic beta-Agonists↗
PubMed1984

Cellular immunity in renal failure: depression of lymphocyte transformation by uraemia and methylprednisolone. Intra-individual consistency of lymphocyte responses to the in vitro suppressive effect of steroid.

In vitro parameters of the cell-mediated immunity were assessed in patients with chronic renal failure on haemodialysis (HD). The in vitro mitogen responses of uraemic lymphocytes are depressed compared to control lymphocyte cultures. Prolonged or shortened incubation of uraemic cultures does not normalize the mitogen responses, and the difference is reflected in both DNA, RNA and protein synthesis of lymphocytes. Lymphocyte responses of control cultures incubated with uraemic plasma are similar to those of cultures with saline, and significantly stronger (p less than 0.05) than those of the uraemic lymphocyte cultures. The relative in vitro immunosuppressive effect of steroid is stronger in uraemic cultures. Thus the depressed uraemic lymphocyte responses may be associated with steroid-sensitive cellular interactions independent of incubation periods. However, both control and uraemic lymphocyte cultures have a reproducible individual in vitro lymphocyte response to the immunosuppressive effect of steroid.

Adult↗
PubMed1984

Renal and hepatic extraction of carboxyl-terminal immunoreactive parathyrin in normal man.

We measured the carboxyl-terminal immunoreactive parathyrin (parathyroid hormone) in samples from twenty catheterized patients with hypertension. The radioimmunoassay reacted equally well with intact parathyrin and carboxyl-terminal parathyrin fragments. The renal arterio-venous extraction ratio (extraction ratio = arterio-venous concentration difference divided by the arterial concentration) of endogenous carboxyl-terminal immunoreactive parathyrin equalled that of inulin, with mean values for both of 0.17. The carboxyl-terminal parathyrin fragments have about the same molecular weight as inulin, and they are extracted exclusively by glomerular filtration, whereas intact parathyrin is extracted by both peritubular uptake and glomerular filtration. The findings therefore agree with a high proportion of circulating carboxyl-terminal parathyrin fragments in normal man. The mean extraction ratio of endogenous carboxyl-terminal immunoreactive parathyrin across nine livers was 0.16. Some of the hepatic extraction might be due to cleavage and uptake of intact parathyrin, which constitutes about 15% of the circulating immunoreactive parathyrin, but the findings suggest that the liver also extracts and metabolizes the circulating carboxyl-terminal parathyrin fragments in normal man.

Amino Acid Sequence↗