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Biomedical subjects

N Rossing

Publications and source records attributed to N Rossing.

At least 73 records · Page 4Linked to original sources
PubMed1978

Kinetics of human connecting peptide in normal and diabetic subjects.

The metabolic clearance rate (MCR) of synthetic human connecting peptide (C-peptide) was measured with a single-dose injection technique in six normal and seven diabetic subjects and with a constant infusion technique in one normal subject. The MCR of C-peptide did not differ in normal subjects (4.4 ml/min per kg; range, 3.7-4.9) and in diabetic subjects (4.7 ml/min per kg; range, 3.7-5.8). Employment of both techniques in one subject gave similar MCR. The average half-life of C-peptide in plasma calculated from the last 1-h period of the single-dose injection studies was longer in the insulin-dependent diabetics (42.5 min; range, 39.4-48.5) than in the normal subjects (33.5 min; range, 24.9-45.3). These results indicate that the beta-cell secretory capacity of normal and insulin-dependent diabetic subjects can be compared by measuring the C-peptide concentration in peripheral venous plasma. The difference in the half-life of C-peptide in plasma between diabetics and normals suggests an altered kinetics of the disappearance of the peptide, while the overall metabolism, as expressed by the MCR, is similar.

Adult↗
PubMed1978

The glomerular filtration rate determined with 99mTc-DTPA and a portable cadmium telluride detector.

In twenty-two patients with 51Cr-EDTA renal clearance (glomerular filtration rate) values of 36-141 ml/min, the final plasma disappearance rate constant of i.v. injected 99mTc-DTPA (Sn) was found to be very close to that of 51Cr-EDTA determined from 180 to 300 min after injection. The disappearance of i.v. injected 99mTc-DTPA (Sn) was also recorded from the body surface by means of a low weight cadmium telluride detector (CRN, Strasbourg, France) and commercially available stationary or portable tape recorders. The disappearance rate constant of 99mTc-DTPA as determined externally from 30 min was comparable to that in plasma determined from 180-300 min. The external rate constant could be converted to plasma clearance by means of one plasma 99mTc-activity determination 180 min after injection. The calculated values agreed with the conventionally determined 51Cr-EDTA clearance values. The portability of the detector system allows it to be used to estimate alterations in GFR during the measurement due to changes in physical conditions such as posture, exercise, etc.

Equipment and Supplies↗
PubMed1978

Comparing the performance of two gamma cameras under high counting rates: principles and practice.

The performance of two large Anger cameras at high counting rates was compared, and the principles for measuring the relevant parameters, especially deadtime loss and coincidence artifacts, are discussed. The results demonstrate the importance of the following factors: modern pulse-shaping circuitry with short paralyzable deadtime, and anti-pileup circuit, and uniform energy information within the field of view, which requires separate summing matrices for energy and position. Elaborate testing of the specifications should be carried out before purchase of a gamma camera.

Evaluation Studies as Topic↗
PubMed1978

Intra- and extravascular distribution of albumin and immunoglobulin in man.

The plasma proteins are constantly shuttling between intravascular and extravascular mass of a specific plasma protein is determined by its individual rate of synthesis and the mean total time it spends in plasma. The ratio of intravascular to total mass (distribution ratio) is determined by the relative rate, at which it passes from plasma to interstitial spaces (transcapillary escape rate: TER) and the relative return rate via lymph. TER in a specific organ depends on the local leakiness of the microvasculature. The overall value in normal man varies with the molecular weight of the protein being about 5%/h of the intravascular albumin mass, 3%/h for IgG and less than 1%/h for IgM. The higher the TER, the lower is the intravascular fraction. Hypertension, diabetes mellitus, burns, myxedema and certain types of liver cirrhosis will increase TER. In hypertension and diabetes this may be compensated for by an increased lymphatic return rate. Hypoproteinemia due to malnutrition or urinary or gastrointestinal loss is accompanied by a shift from the extravascular to the intravascular space.

Agammaglobulinemia↗
PubMed1977

Transcapillary escape rate of albumin and plasma volume in patients with varying degrees of psoriasis.

Plasma albumin, plasma volume and the transcapillary escape rate of albumin (TERalb), i.e. the fraction of the intravascular mass of albumin that passes to the extravascular space per unit time, were determined using 125I-labelled albumin in 26 patients with varying degrees of psoriasis. For the patients as a group the plasma albumin concentration and the TERalb values were not significantly different from the control group. This contrasts with earlier findings in erythrodermic patients. The plasma volume was significantly reduced whether it was expressed in relation to body weight, height or surface area (P less than 0.001). Thus the intravascular mass of albumin (IVM), determined as the product of the plasma volume and the plasma albumin concentration, was also significantly reduced (P less than 0.001). We found no correlation between the involved skin area and any of the above mentioned parameters. The possible mechanisms in the reduction of the plasma volume and the IVM are discussed. It is suggested that reduced IVM may reflect reduced total albumin mass due to lowered rates of albumin synthesis or increased rates of turnover.

Adolescent↗
PubMed1976

Plasma volume, intravascular albumin and its transcapillary escape rate in patients with extensive skin disease.

Plasma volume and plasma concentration and transcapillary escape rate of albumin (TER alb), i.e. the fraction of intravascular mass of albumin that passes to the extravascular space per unit time, were determined using 125I-labelled human albumin in eight patients with extensive skin disease. Plasma volume and plasma albumin concentration were reduced (P less than 0-05). Thus the intravascular albumin mass was moderately decreased to an average of 0-55 +/- 0-06 (s.d.) g/cm height compared with a normal mean value of 0-77 +/- 0-07 (s.d.) g/cm. This 29% decrease is statistically significant (P less than 0-001). The transcapillary escape rate of albumin (TER alb) was significantly elevated, mean 8-6 +/- 1-1 (s.d.) % X h-1, as compared to normal subjects, mean 5-6 +/- 1-1 (s.d.) % X h-1, (+54%, P less than 0-001). The same patients were studied again after a 1-week treatment with prednisone, 25-60 mg per day. Plasma albumin concentration, plasma volume and intravascular mass of albumin were unchanged, while TER alb decreased significantly during treatment, mean 5-9 +/- 0-8 (s.d.) % X h-1, (P less than 0-01). It is suggested that displacement of albumin into the skin and loss of albumin from the skin are the dominating mechanisms of the reduction in the intravascular albumin mass in patients with extensive skin disease.

Aged↗
PubMed1975

Increased metabolic turnover rate and transcapillary escape rate of albumin in long-term juvenile diabetics.

The metabolic turnover rate and transcapillary escape rate of albumin were studied with 131I-labelled human albumin in nine patients with long-term diabetes mellitus. Retinopathy was present in all patients and nephropathy in four. Plasma albumin concentration and plasma volume were reduced (P smaller than 0.05). The previously reported decrease in the intravascular albumin mass in long-term diabetics was thus confirmed by an average of 59.0 g/m2 surface area, compared with a normal value of 71.7 g/m2-(minus18%) (P smaller than 0.005). The albumin metabolic rate was increased, the fractional disappearance rate being an average 13.2% of the intravascular albumin mass per 24 hr, compared with a normal value of 8.4% (+ 57%) (P smaller 0.001). The rate of synthesis was 7.7 g - 24 h-1 - m-2 in contrast to a normal rate of 6.2 g - 24 h-1 - m-2 (+24%) (P smaller 0.001). Total body albumin mass was decreased proportionally to the intravascular mass. Confirming previous observations, we found an increase in the transcapillary escape rate of albumin (fraction of intravascular albumin mass passing to the extravascular space per unit time) from a normal average of 5.6% - hr-1 to 7.4% - hr-1 (+32%) (P ssmaller than 0.001). This finding can best be explained by an increased microvascular permeability to plasma proteins. A positive correlation between the transcapillary escape rate and fractional disappearance rate of albumin was demonstrated ( r equals 0.74; P smaller than 0.01). This supports the concept that albumin is catabolized in connection with its permeation through the microvascular endothelium.

Adult↗