Search PubMed⌕ Search

Biomedical subjects

S Fugleberg

Publications and source records attributed to S Fugleberg.

27 records · Page 2Linked to original sources

The effect of oral aluminium salts on the bone of non-dialysed uremic patients.

12 patients with conservatively treated uremia were investigated using bone histomorphometry, bone aluminium concentration determination and total body bone mineral content (TBBM). The bone aluminum was raised in 10 patients and was significantly related to oral aluminium salt consumption (p less than 0.01). Two of four patients who had not received aluminium also had raised levels but the difference was not significant from nonuremic patients. The two patients with the highest levels had a mineralisation defect despite normal levels of 1,25-dihydroxyvitamin D. Three patients had significant bone loss of whom one had osteomalacia (OM) while two had secondary hyperparathyroidism (2HP). It is concluded that 1) aluminium salt consumption results in bone aluminium accumulation, and may contribute to the mineralisation defect; 2) uremic patients not treated ith aluminium salts may have slightly raised levels, but this seems not to be clinically important; 3) secondary hyperparathyroidism causes greater destruction of bone mass than other uremic bone diseases; 4) atomic absorption spectrometry is a more sensitive method for detecting aluminium bone deposition than histochemical methods.

Acetates↗

Computer-assisted diagnosis of acute azotemia.

We designed a computer program to make diagnostic suggestions in cases of acute azotemia. The performance of the program was tested in a retrospective manner on 63 patients with acute azotemia. The program correctly identified 90 of 94 diagnoses and made 20 false positive diagnostic suggestions. A revised version of the program correctly identified 94 of 94 diagnoses and made 4 false negative suggestions. The justification for this kind of diagnostic aid is discussed.

Artificial Intelligence↗

Kinetic models for plasma disappearance of insulin in normal subjects.

Three theoretical kinetic models for plasma disappearance of insulin were examined in six normal men. The models allowed for the existence of non-saturable and/or saturable mechanisms. Constant infusion of porcine insulin at different rates was used to achieve different levels of steady state plasma insulin concentrations, while normoglycaemia was secured by a glucose clamp technique. Appropriate validation procedures demonstrated that one of the three models was superior to the others in describing the relationship between the exogenous insulin infusion rate Iex and the steady state plasma insulin concentration C: Iex = -Iend + k2 X C/(k3 + C), where Iend is the endogenous post-hepatic insulin delivery rate. Thus, only saturable mechanism(s) could be demonstrated. The median value of k2 (the maximal insulin disappearance rate) and k3 (the plasma insulin concentration at which the insulin disappearance rate is half maximal) were 7.31 nmol X min.-1 and 3.89 nmol X 1-1. The median value of k2/k3 (the clearance rate of insulin for infinitesimal plasma insulin concentrations) was 25.0 ml X kg-1 X min.-1. Thus, at physiological levels of plasma insulin concentrations the metabolic clearance rate of insulin is higher than insulin clearance estimates previously reported in studies based on the assumption of first order kinetics.

Adolescent↗

The relationship between plasma concentration and plasma disappearance rate of immunoreactive insulin in normal subjects.

To investigate the mechanism of insulin degradation in normal subjects, a kinetic model of insulin disappearance was constructed: insulin was assumed to be extracted from plasma by two independent processes, one saturable and one non-saturable. On the basis of these assumptions, a linear (non-proportional) relationship between steady-state plasma insulin concentration and steady-state plasma disappearance rate was predicted over the concentration range studied. Constant infusion experiments were performed on eight healthy normal subjects, normoglycaemia and fasting plasma C-peptide concentrations being maintained during the experiments. Agreement was found between the predictions of the model and the experimental results, and it is concluded that insulin degradation in normal subjects may be described in terms of two processes: one that is saturated at physiological plasma insulin concentrations and one that is apparently non-saturable over a wide concentration range.

Antigens↗

Parameter estimation in six numeric models of transperitoneal transport of glucose.

Six competing kinetic models of transperitoneal glucose transport were formulated and validated. The models were designed to elucidate the presence or absence of diffusive, nonlymphatic convective and lymphatic convective solute transport. The validation procedure included an assessment of theoretical and practical identifiability, goodness of fit, residual error analysis, and plausibility of parameter estimates. Experimental results were obtained from 21 patients without diabetes. The validation procedure demonstrated that the model that only included diffusion was superior to the other models. Theoretically, both nonlymphatic convective and lymphatic convective transports might exist. However, neither the ultrafiltration sieving coefficient nor the lymphatic flow rate were practically identifiable, probably because any amount of glucose transported by nonlymphatic convective and lymphatic convective transport mechanisms was negligible compared with the amount transported by diffusion. Based on these results, there appear to be problems measuring convective solute transport parameters when the solute transport is in the dialysate-to-blood direction while the fluid transport is in the blood-to-dialysate direction.

Adult↗