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Biomedical subjects

G Fex

Publications and source records attributed to G Fex.

At least 37 records · Page 2Linked to original sources
PubMed1987

Studies of the spontaneous transfer of retinol from the retinol:retinol-binding protein complex to unilamellar liposomes.

The transfer of retinol from its complex with the retinol-binding protein to cell surfaces was studied using unilamellar liposomes as a cell surface model. The transfer of retinol to liposomes at 37 degrees C was rapid and reached an apparent equilibrium within 60 min. The amount of retinol transferred to the liposomes at equilibrium was directly proportional to the starting concentration of retinol:retinol-binding protein over a wide range of retinol:retinol-binding protein concentrations and also directly proportional to the concentration of liposomal phospholipid in the system, when the concentration of retinol:retinol-binding protein was held constant. The transfer increased slightly with temperature. Transfer was increased by a factor of 1.8 at pH 4.5 compared to pH around 7. Prealbumin in amounts sufficient to complex all retinol:retinol-binding protein, decreased retinol transfer to liposomes indicating that prealbumin increases the affinity of retinol-binding protein for retinol. Addition of apo retinol-binding protein to the system decreased the transfer of retinol to liposomes considerably probably through competition with the liposomes for retinol. In similarly designed experiments delipidated bovine serum albumin competed much less with liposomes for retinol. The results show that spontaneous transfer of retinol from the retinol:retinol-binding protein complex to liposomal membranes occurs in vitro and suggests that a similar transfer may occur in vivo from retinol:retinol-binding protein to cell surface membranes.

Humans↗
PubMed1987

A circulating complex between ASAT and IgG in serum in an apparently healthy woman.

An elevated level of serum aspartate aminotransferase (ASAT) activity in a subjectively healthy woman was shown to be due to circulating ASAT:IgG complexes. The complexes were demonstrated by taking advantage of the specific interaction between protein A and IgG. Thus, greater than 90% of the patient's ASAT activity in serum could be bound to protein A-Sepharose demonstrating that nearly all the patient's serum ASAT was complexed to IgG. The ASAT-binding capacity of patient serum was calculated as approximately 850 micrograms ASAT/l which corresponds to about 0.01% of patient's IgG.

Adult↗
PubMed1987

Low plasma selenium as a risk factor for cancer death in middle-aged men.

In a population study, 10,000 men (aged 46-48 years) were invited to a health screening program. At follow-up, which was up to eight years later, 61 subjects had died from cancer; from 35 of these subjects, plasma samples were available that were obtained at the initial screening. These samples, together with samples from two living controls for each case, were analyzed for selenium, retinol, cholesterol, triglyceride, and a number of plasma proteins. Plasma selenium was significantly lower (p less than 0.05) in cases than in controls (means: 1.06 vs. 1.12 mumol/l). The proportion of cases increased significantly from the highest to the lowest quintile of plasma selenium, and the relative risk for cancer death was 3.8 times higher in the lowest quintile compared with the highest. Mean plasma retinol was similar in cases (2.53 mumol/l) and controls (2.56 mumol/l). Cases and controls also had similar values for plasma cholesterol, triglyceride, uric acid, apolipoprotein B, orosomucoid, prealbumin, retinol-binding protein, and beta 2-microglobulin. Apolipoprotein AI in plasma was lower among cases (p less than 0.025). Cases smoked significantly more than controls did (p less than 0.05). Data indicate that low plasma selenium was a risk factor for cancer death in middle-aged men who lived in the same area. Further studies are necessary to establish whether differences in selenium intake, selenium metabolism, or other factors related to selenium are responsible for the relations observed. At present, the available data do not justify selenium supplementation programs in the whole population.

Apolipoprotein A-I↗
PubMed1987

Hyperlipidemia in school children with family histories of premature coronary heart disease.

Children starting their schooling were given a questionnaire asking about the occurrence of premature (before 50 years of age in men, 55 years in women) coronary heart disease (CHD) in first degree relatives. 1,920 of 2,069 questionnaires were answered, 140 of the 7-year-old children were reported to have a first degree relative with premature CHD, 84 of these 140 families agreed to participate in our study. In 79 of the 84 families both the child and the parent at 'high risk' were tested. In the initial test 19 of 84 children had total cholesterol (TC) levels above the 95th percentile (greater than 5.35 mmol/l). In the repeat test 12 of the 19 TC tests remained abnormal and all 12 also had LDL-cholesterol (LDL-C) levels above the 95th percentile (greater than 3.40 mmol/l). None had abnormal HDL-cholesterol or triglyceride levels. Among the high risk parents, 12 of 79 had abnormal initial blood lipid tests. In the repeat test 10 parents had both TC and LDL-C levels above the 95th percentile. In five families both the child and the parent had abnormal TC and LDL-C levels. In conclusion, a considerable proportion of children and parents with family histories of premature CHD have TC and LDL-C concentrations above the 95th percentile (in the present study, about 40 individuals in 140 high-risk families, if the parent and child considered at high risk all had agreed to participate). Prevention of heart disease should begin in childhood when patterns of life-style are developed. Identification by obtained family histories as in the current study may be a method of choice.

Child↗
PubMed1987

Post-transfusion hepatitis type non-A, non-B in southern Sweden: occurrence and clinical significance.

Two prospective studies of the occurrence and clinical significance of post-transfusion hepatitis non-A, non-B were performed in Malmö, Sweden. In both studies, patients of a broad clinical spectrum were followed up 6 and 12 weeks after transfusion. In a 7 week study from 1983, hepatitis non-A, non-B occurred in 9/173 transfused patients (5.2%) versus 1/203 untransfused controls (0.5%) (p less than 0.01). In a 6 month study from 1984-85, the incidence of hepatitis non-A, non-B had declined to 2.4% (18/739 transfused patients). The mean number of transfused units was about 5 in both studies and most patients had subclinical disease. Despite similar transfusion volumes to patients above or below 70 years of age, hepatitis non-A, non-B was predominantly seen among patients less than 70 years. In the 1984-85 study, hepatitis non-A, non-B incidence was 1.2% in recipients greater than or equal to 70 years, 3.4% in recipients less than 70 years and 4.5% in recipients less than 40 years. One year after the initial hepatitis non-A, non-B episode, 4/18 patients (22%) had biochemical signs of chronic hepatitis.

Age Factors↗
PubMed1987

Hospital nutrition in geriatric long-term care medicine. I. Effects of a changed meal environment.

Sixteen patients, five males and 11 females, (mean age 80.4 years, range 65-88 years) were studied before, during and after a changed meal environment in a long-term care ward. The dining-room was redecorated in a way similar to what was common during the 1940s. The food was served by the staff on serving-dishes, and the patients could help themselves. A 1-day dietary record was made once a week during the whole study. During the pre-experimental period the average daily intake of energy was 5.8 MJ/1379 kcal and the intake of vitamin D only 2.8 micrograms. During the experimental period the intake of energy and protein increased by 25% (p less than 0.001). No significant changes in body weight occurred which might reflect an increased physical activity. Among the blood chemistry variables blood folate, serum creatinine and retinol showed a significant increase during the experimental period. The changes in retinol might reflect a substitution of a marginal vitamin A deficiency. During the postexperimental period the decrease of serum creatinine was correlated to a decreased protein intake. The intake of energy, protein, vitamin D and thiamine decreased during the last period.

Aged↗
PubMed1986

Studies of cellular retinol-binding protein (CRBP) in squamous-cell carcinomas of the head and neck region.

Cellular retinol-binding protein (CRBP) concentration was determined by radioimmunoassay in biopsies from normal mucosa and squamous-cell cancers of the head and neck region in 26 patients. The plasma concentrations of retinol, retinol-binding protein (RBP), prealbumin, albumin, orosomucoid and alfa1-antitrypsin were also determined. In all patients the tumours contained significantly higher concentrations of CRBP (median = 185 micrograms/g tissue protein; range: 27-1,017 micrograms/g) than normal mucosa (median = 14 micrograms/g tissue protein; range 6-97 micrograms/g). CRBP could not be detected in patient plasma. The tumor/normal mucosa CRBP concentration ratio showed a significant inverse correlation to a histopathological malignancy grade score evaluating the tumour-host relationship, suggesting that tumours with high CRBP relative to normal mucosa are biologically less aggressive. Tumour CRBP showed no correlation either to CRBP concentration in normal mucosa, or to plasma retinol or plasma retinol-binding protein concentration. CRBP concentration in normal mucosa, however, showed a significant correlation to plasma retinol-binding protein concentration. Most of the patients had low levels of plasma retinol and retinol-binding protein compared to matched controls. Whether this has any relationship to the development of the tumour, or whether the active inflammation induced by the cancer leads to a low plasma retinol concentration, is unknown.

Adult↗
PubMed1986

Low serum apolipoprotein A-I in acute myocardial infarction survivors with normal HDL cholesterol.

High density lipoprotein (HDL) cholesterol, apolipoprotein A-I (apo A-I), gamma-glutamyl-transferase, testosterone and oestradiol were determined in plasma in non-diabetic males who had survived an acute myocardial infarction (AMI) before the age of 60. They also had serum levels of cholesterol below 7.0 mmol/l 1 year after the AMI. On the basis of diastolic blood pressure they were subdivided into 2 groups with diastolic blood pressures below 90 mm Hg (n = 39), and with or above 95 mm Hg (n = 21) and then compared with an age-matched male non-diabetic reference group (n = 32). There were no significant differences in the levels of HDL cholesterol, gamma-glutamyl-transferase, and sex hormones between the AMI groups and the reference group. Reduced plasma levels of apo A-I were found in the AMI groups.

Analysis of Variance↗
PubMed1985

Cellular retinol-binding protein in normal and neoplastic human mammary gland.

The concentration of cellular retinol-binding protein (CRBP) was determined in samples of normal and neoplastic mammary gland, using a specific and sensitive radioimmunoassay. The CRBP concentration was significantly higher in neoplastic tissue, but detectable levels were also present in all samples of normal gland. Tubulo-ductal cancers had significantly lower CRBP levels than other cancer types. The CRBP concentration of the neoplastic tissue showed no correlation with the concentration of progesterone or estrogen receptor.

Adenocarcinoma↗
PubMed1985

Prealbumin in Swedish patients with senile systemic amyloidosis and familial amyloidotic polyneuropathy.

A prealbumin (PA)-like protein was demonstrated in amyloid fibrils both from a patient with senile systemic amyloidosis (SSA) and from a patient in northern Sweden with familial amyloidotic polyneuropathy (FAP). The investigated properties of this protein were similar in the two types of fibrils. The protein had molecular weight, antigenic determinants, and at least one cysteinyl residue in common with the subunit of normal PA. In contrast to normal PA, it contained disulphide-linked subunits and was to some extent bound to the fibril via the cysteinyl residues. The noncovalent forces between its subunits were weaker than in normal PA. It constituted part of the previously described AScl protein of the SSA fibrils. Proteins with lower molecular weight than the PA monomer were major proteins in both SSA and FAP fibrils. These proteins had similar properties in the two kinds of fibril and may be derived from PA. PA in serum from Swedish patients with FAP and SSA was normal with regard to the isoelectric pH of the monomers and tetramers.

Adult↗
PubMed1985

Rates of synthesis of prealbumin and retinol-binding protein during acute inflammation in the rat.

The rates of synthesis of prealbumin (PA), retinol-binding protein (RBP), and other plasma proteins were measured in primary monolayer cultures of rat hepatocytes isolated from normal rats and from rats 18 h after induction of an inflammatory reaction by subcutaneous injection of croton oil. The inflammatory pattern of protein synthesis seemed to persist in the isolated hepatocytes for 1-2 days. This pattern included significantly decreased rates of synthesis of PA. The rate of synthesis of RBP was probably also decreased, but significantly less than the rate of PA synthesis. The results support the idea that it is mainly the decreased rate of PA synthesis which is responsible for the decreased plasma concentration of PA, and its ligand RBP and retinol during inflammation.

Acute Disease↗
PubMed1985

Pulmonary arterial-venous differences in lipids and lipid metabolites.

This study was designed to reevaluate the effectiveness of the lungs in taking up lipids from the blood, and to establish whether or not the blood triglycerides so extracted are metabolized. 8 normal human males were studied. With the subject fasting and supine, a percutaneous catheter was placed in the pulmonary artery, another in the superior vena cava, and a third in the brachial artery. Samples of mixed venous and arterial blood were drawn by syringe from the pulmonary and brachial arteries, respectively. Infusion of a triglyceride emulsion (20% Intralipid) into the superior vena cava was begun at 4.7 ml/min. After 12 min of infusion, mixed venous and arterial samples were taken and infusion was discontinued. 15 min following termination of infusion, blood samples were again drawn. Analysis showed the lungs to be retaining about 25% of available triglyceride. Cholesterol concentration was unaffected. Arterial-venous differences in glycerol and free fatty acid were insignificant, suggesting no metabolism of triglyceride by lungs. The lungs apparently serve as a mechanical screen to triglyceride.

Adult↗
PubMed1984

Factors affecting the concentration of free holo retinol-binding protein in human plasma.

The total concentrations of retinol, retinol-binding protein and prealbumin were determined in plasma from twenty healthy men and sixty patients with various inflammatory conditions. These concentrations were all strongly correlated to each other and lower in the patient group. The concentration of free (not prealbumin-bound) holo retinol-binding protein, the presumed 'active' supplier of retinol to the tissues, was calculated. It was found not to be decreased in the patient group. Of the measured total concentrations and their possible ratios in the whole material, the retinol/prealbumin ratio showed the strongest correlation to the concentration of free holo retinol-binding protein. The importance of the concentration of free holo retinol-binding protein for the vitamin A supply to the cells was supported by calculations on data from the literature showing that this concentration better than the above-mentioned total concentrations distinguished between patients with normal and abnormal dark adaptation ability.

Adaptation, Ocular↗
PubMed1984

CSF cation changes following subarachnoid injection of iohexol and metrizamide in rabbits.

Forty anaesthetized rabbits were injected subarachnoidally with equimolal doses, 0.48 mmol/kg body weight (= 185 mg I/kg), of iohexol and metrizamide, administered in solutions iso- and hyperosmolal to the CSF. Concentrations of Na, K, Ca and Mg in the CSF were determined before and 3 hours after the contrast medium injections. Iso-osmolal iohexol caused a uniform decrease in all four cations, which was believed to be a simple dilution. The hyperosmolal solution of iohexol caused a significant relative increase in Ca compared with Na, K and Mg. Both metrizamide solutions caused an increase in Ca over its pre-injection level and a significant relative increase of both Ca and Mg as compared with Na and K. The changes caused by the three latter solutions were consistent with an increase in the blood-brain barrier permeability.

Animals↗
PubMed1984

Alcohol-related problems in middle-aged men with elevated serum gamma-glutamyltransferase: a preventive medical investigation.

In an ongoing population study in Malmö, Sweden, serum gamma-glutamyltransferase (GGT) was used both as an indicator of alcohol-related problems and as an aid in further investigation and treatment. The study group was consecutively selected from six middle-aged male birth-year cohorts of 8859 screening attenders (76.1% attendance), and comprised a random one-half (N = 317) of the individuals with screening GGT in the top decentile of the distribution. Alcohol consumption was the main cause of GGT elevation in 76% of the study group. Symptoms of alcoholism were frequent in these subjects but were rare in those with normal GGT levels. Marital and occupational measures were similar to those in the general population for subjects who were still in treatment but differed for subjects who had dropped out within 2 yr. Comparisons of medical and social data, the questionnaire results and other screening measures between the study group and the other subjects with screening GGT in the top decentile showed equivalence between the two groups and indicated that the study group was representative of the entire group with significantly elevated GGT values in the screening investigation.

Age Factors↗
PubMed1984

The increased negative charge of prealbumin in cerebrospinal fluid is acquired in vitro by oxidation of the cysteinyl residues without formation of disulphides.

The reported charge difference between prealbumin (PA) in cerebrospinal fluid (CSF) and PA in plasma has been traced to the cysteinyl residues. In freshly drawn CSF and plasma, PA had the same electrophoretic mobility at pH 8.6 and the same microheterogeneity by electrofocusing under denaturing and nondenaturing conditions. No differences in molecular weight were detected on sodium dodecyl sulphate polyacrylamide slab gel electrophoresis between PA isolated from stored CSF and PA isolated from serum. In fresh samples of CSF and plasma almost all half-cystine residues of PA reacted with 5,5'-dithio bis (2-nitrobenzoic acid) (DTNB). During storage of CSF and plasma the single cys-10 in the PA subunits acquired an extra negative charge and became unreactive towards DTNB due to oxidation mainly without formation of disulphides. This reaction proceeded faster in CSF than in plasma and explains the reported lower isoelectric pH and the higher electrophoretic mobility of PA in CSF compared to the corresponding plasma.

Amino Acid Sequence↗