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Biomedical subjects

K Olgaard

Publications and source records attributed to K Olgaard.

At least 37 records · Page 2Linked to original sources
PubMed1988

Bone mineral content by photon absorptiometry of the mandible compared with that of the forearm and the lumbar spine.

A new method for measuring the bone mineral content (BMC) of the mandible by dual-photon absorptiometry (DPA) has recently been introduced. The purpose of the present investigation therefore was to examine the long-term precision for 32 months in vitro and in vivo for assessment of BMC in the mandible and to examine the relationship in vivo among BMC of the mandible, the forearms, and the lumbar spine as measured by DPA and/or single-photon absorptiometry (SPA). For comparison, the relationship between forearm BMC as measured by DPA and SPA was studied. The long-term precision of the mandibular BMC was 0.8% in vitro, independent of age and change of radioactive source, and 2.1% by assessment in vivo. A significant relationship (P less than 0.01) was found between BMC of the lumbar spine and the forearms and between the two sets of forearm BMC measured by DPA and SPA. Thus, relative BMC changes of the forearms can be compared without respect to type of forearm bone scanner used. The BMC changes of the mandible can only be evaluated by scanning of the mandible itself. The present DPA bone scanner is suitable for follow-up analyses of the BMC changes of the mandible and the forearms.

Adult↗
PubMed1988

Plasma exchange after revascularization compartment syndrome with acute toxic nephropathy caused by rhabdomyolysis.

A 75-year-old man developed acute, fulminating compartment syndrome of the femoral and crural muscles together with acute toxic nephropathy caused by severe myoglobinemia after uncomplicated embolectomy of the common femoral artery. In addition to fasciotomies and administration of mannitol, sodium hydrogen bicarbonate, and furosemide, we performed plasma exchanges on three occasions. The urine and serum concentrations of myoglobin fell from above 180.0 and 50.0 mg/dl, respectively, to 0.14 and 0.11 mg/dl after the third plasma exchange on the ninth day after admission. The serum creatinine concentration was normal on admission, peaked at 2.85 mg/dl, and returned to normal values at discharge. We suggest that plasma exchange may be considered an adjunct to conventional therapy of compartment syndrome with associated acute toxic nephropathy caused by myoglobinemia.

Aged↗
PubMed1988

Metabolism of intact parathyroid hormone in isolated perfused rat liver and kidney.

Metabolism of synthetic human parathyroid hormone (PTH) 2 X 10(-10) to 5 X 10(-9) M was studied in 16 isolated perfused rat kidneys and 12 isolated perfused rat livers. Organ clearances were measured by assays specific for intact PTH. Production of fragments was analyzed by high-performance liquid chromatography (HPLC) and radioimmunoassays specific for NH2-terminal, midmolecule, and COOH-terminal PTH. The livers cleared intact PTH and NH2-terminal immunoreactive PTH (iPTH) at the same rate. Midmolecule iPTH was cleared significantly (P less than 0.001) slower, as was COOH-terminal iPTH (P less than 0.005), and HPLC studies demonstrated production of midmolecule/COOH-terminal PTH fragments, while no NH2-terminal fragments were found. Clearance in the kidneys of intact PTH and of NH2-terminal, midmolecule, and COOH-terminal iPTH was not significantly different from clearance of inulin. No clearance of intact PTH was found in nonfiltering kidneys. HPLC studies did not demonstrate release of any PTH fragments from the kidneys. In conclusion, the liver was not selective for intact PTH, and differential hepatic clearance, possibly together with direct glandular secretion, may contribute to the predominance of COOH-terminal PTH fragments in plasma.

Animals↗
PubMed1988

Hypovolemic stimuli and vasopressin secretion in man.

Different non-hypotensive hypovolemic stimuli were applied to 21 healthy and 20 uremic dialysis patients. The purpose was to study the effect on plasma arginine-vasopressin concentration, using orthostasis as a reference model. Orthostasis increased the plasma AVP level in healthy subjects as well as in uremic dialysis patients. In healthy subjects plasma AVP increased both when they were normohydrated and after they had been water-depleted. Lower body negative pressure (LBNP, -40 mmHg) was applied to 11 healthy males to induce a central blood volume decrease, equal to that induced by orthostasis. The plasma AVP increased in two subjects only who became hypotensive during the investigations. Ten hemodialysis patients were volume-depleted by isolated ultrafiltration. A flow directed Swan-Ganz catheter was used to measure the central intravascular pressures. Pulmonary capillary wedge pressure was reduced to normal or subnormal values during 1-2 h of ultrafiltration, without any significant changes in plasma AVP. Plasma AVP increased only in 2 patients, who became hypotensive during the investigations. Thus, of the present non-hypotensive volume stimuli only orthostasis was able to stimulate AVP secretion. Equal or even greater reductions in central blood volumes by other stimuli had no effect on AVP secretion. The results demonstrate that isolated stimulation of low-pressure volume receptors has no effect on the secretion of AVP in humans.

Adult↗
PubMed1988

Necrosis of the femoral head after renal transplantation.

The cumulated risk of developing necrosis of the femoral head following renal transplantation was 42/374 in patients treated with steroids and azathioprine, and 4/124 in patients treated with cyclosporine-A and a reduced dose of steroids. 29 of the osteonecrosis cases were bilateral, with the time lapse between the two sides rarely exceeding 6 months. The reduction in the rate of osteonecrosis paralleled a reduction in the number of rejection episodes during the first month after transplantation and in the cumulated dose of steroids 1 month and 1 year after transplantation. We concluded that the risk of femoral head necrosis following renal transplantation is reduced by using cyclosporin-A for immunosuppression, which caused less rejection episodes and consequently a reduction in steroid medication.

Adult↗
PubMed1988

Plasma free and sulfoconjugated dopamine in man: relationship to sympathetic activity, adrenal function and meals.

Peripheral venous plasma free and sulfoconjugated catecholamines, dopamine (DA), noradrenaline (NA) and adrenaline (A) were measured in normal men (n = 6-7) during conditions significantly altering adrenal and sympathoadrenal function (influence of corticotropin, furosemide, hypoglycaemia and clonidine), after dopamine receptor blockade with metoclopramide and after meals. Median (range) basal plasma free DA concentration was 0.13 (0-0.72) nmol/l and median (range) basal plasma conjugated DA concentration was 15.16 (6.34-45.03) nmol/l. Meals increased plasma sulfoconjugated DA markedly from a median value of 14.97 nmol/l during fasting experiments to a median value of 33.01 nmol/l (p less than 0.05). Plasma free DA did not change in the meal experiments. No changes in plasma DA were observed after administration of corticotropin, furosemide, clonidine, and metoclopramide or during hypoglycaemia. The results suggest that plasma sulfoconjugated DA is derived at least in part from the gastrointestinal tract and not from the sympathoadrenomedullary system as hitherto proposed.

Adrenal Glands↗
PubMed1987

Isolated perfused rat kidney and liver combined. A new experimental model.

Interaction between hepatic and renal metabolism is found in many endocrine systems. We therefore developed a new experimental model, combining the isolated perfused rat kidney and rat liver. Krebs-Henseleit buffer with bovine serum albumin 67 g X l-1 and amino acids was recirculated to both organs through two rolling pumps, four 8 microns Millipore filters and two specially designed membrane lungs. The kidney was cannulated by a modification of the technique described by Nishiitsutsuji-Uwo 1967 and the liver was cannulated by a modification of the technique described by Hems 1966. Kidney function: Perfusion pressure 12.4 +/- 1.1 kPa (93 +/- 8 mmHg), flow 28 +/- 6 ml X min-1 X g-1, FRNa 94.0 +/- 2.9%, GFR 491 +/- 191 microliters X min-1 X g-1, urine production 48 +/- 34 microliters X min-1 X g-1, FEK 60 +/- 36%. Liver function: Flow 25 ml X min-1 (fixed), portal vein pressure 12 +/- 3 cm H2O, bile flow 0.18 +/- 0.13 ml X h-1, oxygen consumption 2.0 +/- 0.2 mumol X min-1 X g-1. Only minor differences were found between single perfusions (N = 25) and combined perfusions (N = 6). We conclude that it is possible to combine the isolated perfused rat kidney and rat liver without impairment of the function of either.

Animals↗
PubMed1987

The immunosuppressive potency in vitro of physiological and synthetic steroids on lymphocyte cultures.

The immunosuppressive potency of five natural and seven synthetic steroids were tested in vitro on phytohemagglutinin (PHA) stimulated peripheral lymphocytes (PBL) and T-lymphocytes and compared to their anti-inflammatory potencies. The physiological glucocorticoid, hydrocortisone, was of intermediate immunosuppressive potency in vitro, whereas the metabolites of hydrocortisone (cortisone, dihydrocortisol, and tetrahydrocortisol) and aldosterone were without effect. The synthetic steroids, methylprednisolone and fluorohydrocortisone were both highly potent in suppressing the PHA responses of both lymphocyte subsets. Prednisolone and dexamethasone were of intermediate potency and ranked similar to hydrocortisone which is in contrast to their anti-inflammatory properties. Prednisone, the biologically inactive metabolite of prednisolone, was without immunosuppressive properties. Deoxy-deflazacort, the biologically active metabolite of deflazacort (a new oxazoline derivative of prednisolone) was comparable to prednisolone and hydrocortisone in suppressing lymphocyte proliferation but again there was a large discrepancy between the in vitro immunosuppressive effect and the anti-inflammatory potency. In conclusion, the present assay may therefore separate the immunosuppressive properties from the anti-inflammatory properties of glucocorticoids. These findings may be useful for comparison of new synthetic steroids.

Adult↗
PubMed1987

Increased clearance rate of prednisone in the isolated perfused liver of uremic rats.

The effect of uremia upon the hepatic clearance rate of prednisone was studied in isolated perfused livers of normal and uremic female rats. The perfusion rate was kept at a constant flow rate of 25 ml/min. In order to induce uremia, one group of rats was 5/6 nephrectomized 3 weeks prior to the perfusions. The concentrations of prednisone and other steroids were measured by a normal phase HPLC technique. In experiments with an initial prednisone concentration of 500-700 micrograms/l, the hepatic clearance rate of prednisone was significantly (p less than 0.001) increased by 40% in livers obtained from uremic rats (11.1 +/- 0.49 ml/min/liver) as compared to control rats (8.0 +/- 1.17 ml/min/liver). No significant correlation was found between the hepatic clearance rate of prednisone and increasing initial prednisone concentrations from 141 to 1,953 micrograms/l in the perfusate. It is concluded that an adaptive mechanism may exist in uremia which results in an increase of the hepatic clearance rate of prednisone.

Animals↗
PubMed1986

In vitro immunosuppressive potency of deflazacort, a new bone-sparing corticosteroid on T lymphocytes, NK and K cells.

The in vitro immunosuppressive effect of deflazacort, a new bone-sparing glucocorticoid, and its biologically active metabolite, 21-deacetyl-deflazacort, was examined on phytohaemagglutinin (PHA) stimulated human peripheral blood lymphocytes (PBL) as well as on natural killer (NK) and killer (K) cell activity. Deflazacort and the 21-deacetyl metabolite were as potent as prednisolone and hydrocortisone in suppressing PHA stimulated lymphocytes in a dose dependent way, but all were less potent than methylprednisolone. The physiological metabolites of hydrocortisone, dihydrocortisol and tetrahydrocortisol were without any immunosuppressive effects in vitro. Deflazacort, 21-deacetyl-deflazacort, and methylprednisolone suppressed NK cell activity, while hydrocortisone and aldosterone had no effect on NK cells. K cell activity was resistent to all tested glucocorticoids except methylprednisolone at high concentrations. The present results indicate that deflazacort and 21-deacetyl-deflazacort are potent immunosuppressive drugs in vitro and, on a molar basis, equally as potent as prednisolone.

Aldosterone↗
PubMed1986

Pregnancy following kidney transplantation.

Following kidney transplantation, 20 women gave birth to 24 infants after the 28th gestational week. All babies were singletons, alive, and free from malformations. The mean weight was 2,595 g (range 1,420-3,200 g) and the mean gestational age was 37.8 weeks (range 32-40 weeks). The cesarean section rate was 75%. On dividing the patients into low- and high-risk groups, the rate of pre-eclampsia, prematurity, and intra-uterine growth retardation was 2-3 times as high in the high-risk as in the low-risk group. No patients experienced graft rejection during the pregnancy but, within 3 months after delivery, two rejection episodes occurred. Later, a further 5 patients experienced graft rejection. All infants developed normally. We conclude that pregnancy following renal transplantation generally has a normal outcome and that the function of the transplanted kidney is unaffected by the pregnancy.

Adult↗
PubMed1986

Differential biological effects of calcitonin and parathyroid hormone on isolated perfused bone.

These studies examine the release of 3',5'-cyclic adenosine monophosphate (cyclic AMP) from isolated perfused canine bones in response to synthetic bovine parathyroid hormone (syn b-PTH 1-34) and human calcitonin (hCT). Bones for perfusion were obtained from three groups of dogs: control (n = 11); thyroparathyroidectomized (n = 7), and mithramycin-treated thyroparathyroidectomized animals (n = 5). The results indicate that PTH causes a greater release of cyclic AMP from adult bones than CT; the addition of the two hormones simultaneously results in a synergistic rather than an additive effect; mithramycin inhibits the cyclic AMP response to calcitonin; and thyroparathyroidectomy decreases the cyclic AMP release in response to CT stimulation, suggesting that the cells (osteoclast-like) that respond to CT have an impaired response in the absence of PTH; acute TPTX does not affect the response of the cell populations of adult bones to PTH.

Animals↗
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

Sodium homeostasis after small-bowel resection.

In 16 small-bowel-resected patients, 8 with ileostomy and 8 with at least half of the colon in function, plasma volume, plasma aldosterone concentration, plasma renin activity, and the 4-day excretion of sodium and potassium in urine and stools were determined. Patients with ileostomy had a high faecal loss of sodium: 85-181 (median, 149) mmol/24 h, and were all more or less sodium-depleted with decreased plasma volume of 1.4-2.5 (median, 2.0) l/175 cm (normal range, 2.3-3.8l/175 cm), increased plasma aldosterone of 742-2250 (median, 1131) pg/ml (normal range, 33-220 pg/ml), and extremely low sodium excretion in the urine of 0-3 (median, 1) mmol/24 h. Patients with similar small-bowel resection but with at least half of the colon in function had a much smaller faecal sodium loss of 1-66 (median, 8) mmol/24 h. They showed significantly higher plasma volume, 2.2-3.7 (median, 2.6) l/175 cm; normal plasma aldosterone, 25-232 (median, 124) pg/ml; and normal or almost normal sodium excretion in the urine, 49-168 (median, 118) mmol/24 h. Six jejunostomy patients, who sustained a normal or almost normal sodium balance thanks to parenteral saline, had intravenous infusion over 6 h of 1000 ml isotonic sodium chloride with or without aldosterone added. During aldosterone infusion plasma aldosterone increased to the level in the sodium-depleted ileostomy patients. Urinary sodium excretion decreased significantly. Stomal sodium loss did not change. It is concluded that small-bowel resection in ileostomized patients causes excessive faecal sodium loss and results in chronic sodium depletion with severe secondary hyperaldosteronism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗