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Biomedical subjects

R Hällgren

Publications and source records attributed to R Hällgren.

At least 235 records · Page 13Linked to original sources
PubMed1979

Kinetics of the agglutination of IgG-coated latex particles by C1q: the influence of heat-labile serum components.

Interaction between human C1q and IgG coated latex particles has been studied by means of a standard aggregometer equipment. A dose-dependent agglutination was observed and 100 ng of C1q were readily detected. The kinetics of the agglutination was also monitored. Serum, partially purified C1, and high molecular weight fractions from Sephadex G-200 fractionated serum produced agglutination only in the presence of EDTA. In the absence of this chelator these products disintegrated preformed C1q-IgG-latex particle agglutinates. This disagglutinating principle is heat-sensitive and tentatively macromolecular C1 dependent. The most probable basis of the activity is the competition between C1, with a high affinity for IgG particles, and C1q. The inability of C1 to induce particle agglutination might be caused by the C1 subunits C1r and C1s sterically inhibiting the subunit C1q to bridge between the particles.

Agglutination↗
PubMed1979

Gastric acid secretion in uraemia and circulating levels of gastrin, somatostatin, and pancreatic polypeptide.

Basal circulating levels of gastrin, somatostatin, and pancreatic polypeptide were measured in 30 chronic haemodialysis patients. Five patients had considerably raised serum gastrin (greater than 400 pmol/1) and also gastric achlorhydria while 75% of the patients who had normal (less than 55 pmol/1) or moderately increased (less than 400 pmol/1) serum gastrin had raised maximal acid outputs. Patients with serum gastrin greater than 400 pmol/1 had significantly lower plasma concentrations of somatostatin compared with both healthy individuals and uaremic patients with normal gastrin levels. Raised serum concentrations of pancreatic polypeptide were observed in the majority of the patients but no correlation was found between this peptide and gastric acid secretion or circulating levels of gastrin and somatostatin, respectively. Prolonged circulation time for gastrin and pancreatic polypeptide was demonstrated after food stimulation. Prolonged gastrin stimulation of the parietal cell mass may lead to work hypertrophy and gastric acid hypersecretion. Whether long-standing over-stimulation by gastrin also may induce atrophy of the cells remains to be studied.

Adolescent↗
PubMed1979

Renal function in patients on lithium treatment.

A cross-sectional study was performed on 66 lithium-treated patients to investigate a possible changed kidney function, using [51Cr]-EDTA clearance, and urinary excretions of albumin and beta 2-microglobulin. Thirteen patients showed abnormal test results: seven had decreased glomerular filtration rate, four had increased albumin excretion and four had increased excretion of beta 2-microglobulin. There was no correlation between length of treatment with lithium or hypothyroidism (10 patients) and impaired renal function. Four patients had already manifested signs of renal dysfunction before lithium treatment. The high prevalence of impaired renal function among our patients is unexplained but lithium could be one possible cause.

Adult↗
PubMed1979

Radioimmunoassays of human myoglobin in serum and urine.

Two solid-phase radioimmunoassays have been developed for the detection of myoglobin in serum and urine. The sensitivity of the methods is 0.1 and 0.5 microgram/l, respectively, with a coefficient of variation of the respective method of 7-8%. The mean serum concentration of myoglobin in ninety-nine healthy blood donors was 44.3 microgram/l +/- 18.0 microgram/l (SD) with a significant difference (P less than 0.001) between men (50.6 +/- 19.8) and women (35.7 +/- 10.4). Serum myoglobin was positively correlated to age (P less than 0.05), body weight (P less than 0.02), serum creatine kinase (P less than 0.001), and serum creatinine (P less than 0.001) to galactose elimination rate. Serum myoglobin levels were not influenced by exhaustive short time dynamic exercise. The mean urinary excretion of myoglobin in twenty-four healthy students was 1.2 microgram/24 h (range 0.1-4 microgram/24 h). Myoglobin excretion was correlated to excretion of beta 2-microglobulin (P less than 0.02) but not to serum levels of myoglobin. No indications of circulating antibodies to myoglobin were obtained when assaying sixty-seven rheumatoid arthritis and thirteen myastenia gravis sera. Presence of other myoglobin binding substances in serum, which would interfere with the assays also seemed unlikely. Determination of myoglobin in serum by sensitive and specific method might be of clinical value in the diagnosis of diseases involving muscle tissues.

Adult↗
PubMed1979

Serum beta2-microglobulin in liver disease.

The concentration of beta 2-microglobulin in serum was determined in seventy-one patients with various liver disorders. Elevated values were found in most patients with chronic active or chronic persistent hepatitis and in over 80% of patients with alcohol-induced liver cirrhosis. In contrast, patients with alcohol-induced fatty liver, the serum beta 2-microglobulin concentrations were mostly within the normal range. Significant correlation (P less than 0.001) was noted between the elimination rate of galactose from blood and the serum beta 2-microglobulin concentration in patients with alcoholic liver damage but not in patients with chronic hepatitis. The reasons for the increased S-beta 2-microglobulin concentrations in liver diseases are unknown. Several explanations including a release of beta 2-microglobulin from necrotic liver cells or an increased synthesis of beta 2-microglobulin consequent to inflammation in the liver are possible. Alternatively, raised beta 2-microglobulin levels may reflect the hepatic synthesis during reparative growth.

Adult↗
PubMed1979

Serum ferritin during infection. A longitudinal study in renal transplant patients.

In order to follow the dynamics in the reaction of iron kinetic variables to acute infection, 8 renal transplantation patients were followed with test samples every second or third day for about two months. It was found that they just as previously shown in otherwise healthy subjects, responded to acute infection with a rise in serum ferritin levels, sometimes to very high values. In most cases the ferritin elevation started within two days after the onset of fever. The peak was reached within a week, except when very high values were obtained. The fall in serum ferritin after recovery from infection was much faster than in previously investigated groups of patients: the plasma half disappearance time for ferritin in one case was but 1.5 days. Transferrin did not change in response to infection. The expected fall in serum iron during infection was often absent and sometimes obscured by unexpected, sharp peaks in serum iron, which bore a temporal relationship to episodes of transplant rejection in 7 of 12 cases.

Acute Disease↗
PubMed1978

Serum ferritin during infection. A longitudinal study.

Serum ferritin, transferrin, iron and haptoglobin have been investigated in a longitudinal study in 18 patients hospitalized for various acute infections. Within a couple of days after the onset of an infection, a rise in serum ferritin was seen, the magnitude of which was not dependent on the type of infection (bacterial or viral). The serum ferritin level remained elevated for several weeks in some patients, and 7 out of the 18 patients still had abnormally high values 5 weeks after the onset of illness. The mean curves for serum ferritin and the acute phase reactant haptoglobin were parallel. Possible mechanisms causing the elevation in serum ferritin are discussed.

Acute Disease↗
PubMed1978

Serum level of immunoreactive gastrin: influence of kidney function.

Serum gastrin levels have been studied in 70 patients with chronically reduced glomerular filtration rate (GFR) as estimated by 51Cr-EDTA clearance, creatinine, and beta2-microglobulin values. A strong dependence upon GFR was found, although the correlation between gastrin levels and GFR was not as high as that between beta2-microglobulin and GFR, indicating the existence of extrarenal factors regulating the levels of circulating gastrin. In a separate group of 31 patients on maintenance dialysis the mean gastrin level was 65.9 pmol/l--that is, a fourfold increase compared to healthy subjects. Three of the uraemic patients had pronounced rises in serum gastrin in the range 800-1800 pmol/l. Finally, the influence of acute alterations of kidney function on serum gastrin was studied in 11 patients undergoing renal transplantation. In addition to a GFR dependence the results indicate the existence of feedback mechanisms in gastrin homeostasis. Although the clinical importance of the increased gastrin levels in renal failure is unknown, hypergastrinaemia occurs with sufficient frequency to be involved in upper gastrointestinal complications of uraemic patients.

Adolescent↗
PubMed1978

Myoglobin turnover--influence of renal and extrarenal factors.

The serum level of myoglobin, an LMW constituent of striated and myocardial muscle, has been studied in various clinical situations in order to obtain information about factors influencing myoglobin turnover. The myoglobin level was significantly correlated to different variables of GFR such as serum beta2-microglobulin, serum creatinine, and 51Cr-EDTA clearance. Following a successful renal transplantation rapid decrease in serum myoglobin was found parallel to increase in GFR's. In patients with advanced long-standing uremia, comparatively small elevations of serum myoglobin were seen when correlated to the degree of GFR reduction, demonstrating an influence of extrarenal factors on the myoglobin levels. The importance of extrarenal factors on the actual serum level of LMW proteins was also illustrated by serial studies on SLE patients receiving corticosteroid therapy. In these patients, elevations of serum myoglobin levels were found, but serum beta2-microglobulin levels gradually decreased during therapy. Finally, calculations based on curves of serum disappearance of myoglobin in patients with acute myocardial infarction indicate that only about 0.3 mg of myoglobin per day is released from the muscle pool during normal conditions, which suggests that myoglobin catabolism mainly occurs within the muscle tissue.

Adolescent↗
PubMed1978

The uptake of IgG and IgM coated sheep erythrocytes in perfused rabbit liver.

Erythrocytes sensitized with IgM and IgG (EA) are entrapped during perfusion of isolated rabbit liver. The binding of EIgG is of high affinity while that of EIgM is weak and partly reversible. Moreover, the binding of EIgM is dependent on the presence of Ca++ ions in the perfusion medium whilst the binding of EIgG is independent of divalent cations. No uptake of sensitized erythrocytes during perfusion of the inferior extremities of rabbits is found.

Animals↗
PubMed1978

Opsonins in human serum for the phagocytosis of complexes between IgG and protein A of Staphylococcus aureus.

The phagocytosis of complexes between staphylococcal protein A and 125I-labelled IgG is enhanced by fresh human serum and to a somewhat lesser extent by heat-inactivated serum. Opsonizing activity is detected in two distinct peaks by Sephadex G-200 column chromatography. One peak corresponds to the excluded material and the other to the ascending limb of the second protein peak. The active material in serum is retained on a protein A-Sepharose but not on an IgG-Sepharose column. Active material eluted from a protein A-Sepharose column and run on a Sephadex G-200 column again shows two activity peaks corresponding to those obtained on chromatography of whole serum. The first peak contains mainly IgA nd IgM but very little total protein material. The second peak contains mainly IgG but also IgA. Purified normal IgA, but not one myeloma IgA preparation tested, has the capacity to enhance phagocytosis of protein A-IgG complexes. Possible examinations for the opsonin activity are discussed.

Chromatography, Gel↗
PubMed1978

Myoglobinemia after myocardial infarction; influence of renal function.

Using a solid-phase radioimmunoassay for detection of serum myoglobin, the pattern of myoglobinemia was investigated in patients with acute myocardial infarction. All patients with acute infarcts had a marked rise in serum myoglobin concentration. Peak serum myoglobin concentration was found on an average 9 h after the initial onset of chest pain. Late onset of myoglobin peaks without signs of reinfarction as well as sustained abnormal myoglobinemia, in the majority of patients, could be explained by impaired renal function. The peak serum level of myoglobin correlated (r = 0.92) to the peak level of ASAT supporting the idea that the detection of myoglobin in serum may be a useful diagnostic aid in the qualitative diagnosis of myocardial infarction.

Aged↗
PubMed1977

Elimination of protein A-IgG complexes from the blood circulation in rabbits: role of spleen and liver.

We studied the elimination from rabbit circulation of soluble immune complexes made with staphylococcal protein A and rabbit IgG. In in vivo experiments the complexes were cleared from the circulation by the liver and spleen. In the saline perfused isolated liver there was rapid uptake of protein A-IgG complexes which indicated that the elimination of these complexes by fixed tissue macrophages may occur independent of complement components.

Animals↗
PubMed1977

Precipitation of 125I-labelled IgG aggregates by factors in sera of healthy individuals and of patients with rheumatoid arthritis.

Several factors in human serum are capable of precipitating soluble 125I-labelled heat aggregated IgG (agg IgG*). A study of the nature of these factors resulted in the development of two new methods for the detection and assay of anti-IgG-immunoglobulins (rheumatoid factors) in serum. One method detected rheumatoid factors of the IgG and the IgA classes which are capable of binding and coprecipitating with Clq and agg IgG* in an EDTA milieu. In a second method the serum was first heat inactivated and the assay was then made in a polymeric milieu where rheumatoid factors of the IgM as well as the IgG and IgA classes could be detected. 67 sera from patients with rheumatoid arthritis were tested with this method and rheumatoid factors were detected in all seropositive (as assayed with conventional rheumatoid factor tests) sera and in 58% of the seronegative sera. In the presence of certain anti-IgG-immunoglobulins or polymers, the precipitation of Clq and soluble agg IgG* is greatly enhanced, and we suggest that this can be used as a basis of a sensitive method for the assay of agg-IgG-binding activity of Clq.

Arthritis, Rheumatoid↗
PubMed1977

Serum levels of human pancreatic polypeptide in renal disease.

The newly recognized pancreatic polypeptide (PP) has been demonstrated in the circulation of healthy subjects, although its physiological role is not definately established. In order to investigate the renal role in the elimination of PP from the circulation, PP was determined in patients with varying degrees of renal damage, in patients on chronic haemodialysis, and in patients who have undergone renal transplantation. A close correlation was found between glomerular filtration rate and serum PP. In the uraemic group, PP levels were highly elevated as compared to normal individuals. After renal transplantation, PP values declined in step with the improvement in glomerular filtration rate. The increased serum PP levels in renal failure raise the possibility of PP being involved in the development of uraemic gastrointestinal symptoms.

Adolescent↗
PubMed1977

Kinetic studies of phagocytosis of IgG-coated latex particles with a thrombocyte counter.

An assay was developed making possible the measurement of the initial rate of phagocytosis of IgG-coated polyvinyl toluene latex particles by human leukocytes. With the use of the volume-discrimating ability of a Trombo-Counter, the small latex particles could be selectively counted, but cells and internalized particles were not counted. The phagocytic uptake was greatley enhanced by an IgG coating of the particles as compared to the uptake of uncoated or albumin-coated particles. An almost complete inhibition of particle uptake was obtained at ice-bath temperature and in the presence of N-ethyl maleimide. Heat-inactivated serum and monomeric IgG inhibited the phagocytic reaction. In the presence of fresh serum a stimulatory effect on the final phagocytic capacity was noticed, but the initial rate of particle uptake varied depending on the preincubation time of particles with serum.

Blood Cell Count↗