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Biomedical subjects

J P Blomhoff

Publications and source records attributed to J P Blomhoff.

At least 19 recordsLinked to original sources
PubMed1997

[Hepatic vein thrombosis. Diagnostic and therapeutic difficulties].

Budd Chiari syndrome (liver vein thrombosis) may be a diagnostic and therapeutic problem. On the basis of four different cases we review the major diagnostic and therapeutic principles involved. Imaging techniques are necessary in order to establish the diagnosis. Ultrasound examination with Duplex doppler is usually sufficient, but MR angiography is also useful. Treatment options are thrombolysis, surgery or liver transplantation. What treatment is selected will depend on the clinical situation and the prognosis.

Adult↗
PubMed1993

[Allogeneic bone marrow transplantation in adult patients with serious hematological diseases 1985-1992].

We present updated results from allogeneic bone marrow transplantation in adult patients who received transplants between 1985 and 1992. Of 47 patients, 36 where disease-free survivors 8-93, mean 32 months after transplantation. Of these, seven had received marrow from unrelated donors. The present treatment capacity is insufficient to cover the demand for allogeneic bone marrow transplants for Norwegian patients.

Adolescent↗
PubMed1992

The genetic defect of the original Norwegian lecithin:cholesterol acyltransferase deficiency families.

Three of the original Norwegian lecithin:cholesterol acyltransferase (LCAT) deficiency families have been investigated for mutations in the gene for lecithin:cholesterol acyltransferase by DNA sequencing of the exons amplified by the polymerase chain reaction. A single T----A transversion in codon 252 in exon 6 converting Met(ATG) to Lys(AAG) was observed in all homozygotes. In spite of the identical mutation, the disease phenotypes differed in severity. This was not reflected in the expression of LCAT in the heterozygotes.

Female↗
PubMed1992

Lipoproteins, lipases, and the metabolic cardiovascular syndrome.

High levels of plasma triglycerides and very-low-density lipoproteins and low levels of high-density lipoproteins are consistently found in the metabolic cardiovascular syndrome. These changes are exaggerated postprandially. In the liver, synthesis and secretion of triglyceride-rich particles are increased. In addition, the removal capacity of plasma triglycerides is decreased, due to downregulation of lipoprotein lipase in skeletal muscles by hyperinsulinemia. Resistance to insulin-stimulated glucose uptake is believed to be the main pathogenetic factor. However, increased flux of free fatty acids from abdominally localized adipose tissue must also be considered when discussing pathogenesis. Treatment is primarily nonpharmacological, with diet and increased physical activity.

Blood Glucose↗
PubMed1991

Liver steatosis in hypobetalipoproteinemia. A case report.

A case of hypobetalipoproteinemia is described; a 16-year-old girl had been suffering for nearly 2 years from diffuse abdominal pain. The only clinical features were liver steatosis, slightly increased amino transferases and an incipient polyneuropathy. No sign of malabsorption or gastrointestinal disease was found. She had extremely low levels of cholesterol and triacylglycerol in her serum, slightly decreased serum phospholipids and normal HDL-cholesterol levels. Apolipoprotein B-100 was approx. 8% of normal, whereas B-48 was present at essentially normal levels. Electron microscopy of lipoprotein particles showed normal morphology of LDL. Examination of close relatives showed no abnormalities. Southern blots revealed no major deletions or rearrangements at the genomic level. Although rare, a- and hypobetalipoproteinemia should be considered as possible etiologies in patients with unexplained steatosis in the liver.

Adolescent↗
PubMed1990

Intracellular regulation of lipoprotein lipase in human monocyte-derived macrophages.

The intracellular pathway of lipoprotein lipase (LPL) has been examined in human monocyte-derived macrophages in culture. These cells were previously shown to synthesize and constitutively secrete LPL. The secretion is dependent on new enzyme synthesis. 6-d-old human monocytes have stores of mRNA for linear release of LPL up to 24 h. Enzyme activity in cells and in culture medium was almost completely inhibited by 24 h treatment with tunicamycin, an inhibitor of glycosylation. In monensin-treated cells a pronounced increase in enzyme activity was found, whereas the secreted activity was markedly reduced. This indicates that LPL in human monocytes is processed through a pH sensitive part of the Golgi complex and that the terminal glycosylation is not needed for the expression of its catalytic activity. Our results suggest that lysosomal function is not important in secretion of the enzyme, whereas vesicular transport seem to be involved in regulating LPL in human monocyte-derived macrophages in culture.

Cell Differentiation↗
PubMed1989

[Drug therapy of hypercholesterolemia. Treatment of hypercholesterolemia in adults--a Norwegian therapeutic program 1988].

There are indications that treatment of hypercholesterolemia by means of drugs reduce risk of atherosclerosis in patients with increased concentrations of atherogenic lipoproteins. Such therapy should be initiated only after satisfactory exclusion of secondary causes of hyperlipoproteinemia, and should be regarded as an adjunct to appropriate dietary therapy. Drug therapy should be strongly considered in patients with total cholesterol above 8-9 mmol/l on diet therapy only. Drug therapy should be considered at even lower concentrations of cholesterol when coronary heart disease is present and in familial forms of hyperlipidemia when increased risk of atherosclerosis has been documented. In patients with increased plasma concentrations of total cholesterol the drugs of choice are agents which enhance the rate of LDL catabolism (resins) or reduce the rate of LDL synthesis (nicotinic acid). Fibrates should be used when triglycerides and cholesterol are both increased. HMG CoA reductase inhibitors offer considerable promise in the therapy of patients with primary hypercholesterolemia. Probucol may be used in combination with other drugs, particularly when xanthomas are present in patients with familial hypercholesterolemia.

Humans↗
PubMed1986

Release of hepatic lipase and very low density lipoprotein by cultured rat hepatocytes.

Primary cultures of rat hepatocytes were used to study the release of hepatic lipase and very low density lipoprotein (VLDL). The presence of hepatic lipase activity was proved by salt-resistance, affinity chromatography and inactivation by a hepatic lipase antibody. Cellular rate of hepatic lipase release increased by prolonged time in culture, whereas VLDL secretion decreased. Oleic acid and dextran-70 had no effect on release of hepatic lipase, whereas VLDL secretion was increased and decreased, respectively. Calcium antagonists (cobalt and verapamil), monensin and cycloheximide inhibited both the release of hepatic lipase and VLDL. Colchicine and chloroquine, which decreased VLDL secretion, had no effect on release of hepatic lipase. The present results suggest that release of hepatic lipase and secretion of VLDL are not coordinated and exhibit different sensitivity towards certain compounds altering secretory functions.

Animals↗
PubMed1986

Identification of homozygosity for a human apolipoprotein A-I variant.

An apolipoprotein (apo) A-I variant, previously described in two Norwegian families (Schamaun et al. 1983. Hum. Genet. 64: 380-383), represents a mutation in apoA-I in which a single amino acid substitution of lysine for glutamic acid has taken place at residue 136. An offspring resulting from intermarriage between the two families is genotypically homozygous for this variant. He is the first individual discovered to be homozygous for any of the apoA-I variants. Analysis of lipid data collected from these families indicates one or more lipid abnormalities. The low density lipoproteins (LDL) of subjects having this apoA-I variant demonstrate a compositional abnormality. The plasma cholesterol concentration in the homozygous subject is low because of the extremely reduced levels of LDL and apoB, a property shared by some of his first-degree relatives. However, because of the presence of apoE2 in this family, it is not possible to definitively link these lipid abnormalities to the presence of the A-I variant.

Adolescent↗
PubMed1985

Follow-up and prospective studies of the classification of liver disease.

Two hundred patients with different liver diseases were observed during a period of 6-8 years. The diagnosis at the first hospitalization was based on morphological criteria (and, in some cases, additional clinical information). In 162 of the cases an initial 'specific' diagnosis could be made. By the time of the follow-up study the diagnosis was confirmed in 73% of them. In 22 of 38 patients who were initially unclassifiable, the diagnosis was made definite by the follow-up study. Eighty-five patients were hospitalized for re-examination 6-8 years after the initial study. Several of the liver diseases initially had quite typical patterns of clinical chemical data. Allocation by discriminant analysis was therefore in good agreement with the morphological classification. The follow-up study showed that several patients with initially atypical patterns of clinical chemical results had their diagnosis changed. In 35 patients with the final diagnosis of chronic active hepatitis (CAH) or primary biliary cirrhosis (PBC), laboratory data from the last hospitalization were used for discriminant analysis with teaching data from the initial study. Ninety-seven per cent were correctly allocated, and we conclude that these patients retain recognizable patterns of laboratory results for several years, even when given immunosuppressive treatment. The potential clinical usefulness of discriminant analysis of laboratory data for differential diagnosis was evaluated by a prospective study of 65 patients with the morphological diagnosis of CAH or PBC. Correspondence with the morphological classification system was found in almost 90% of the cases.

Chronic Disease↗
PubMed1985

Effect of high-density lipoproteins on cholesterol efflux and esterification in lipid-enriched human skin fibroblasts.

The ability of high-density lipoprotein (HDL) to reduce the cholesterol content was studied in cultured fibroblasts enriched with cholesterol esters. Incubation of cholesterol-enriched cells with HDL in a final concentration of 1 g protein/l for 24 h reduced the total and esterified cholesterol content by 23% as compared with control fibroblasts incubated with albumin. Similar cholesterol efflux was obtained with HDL isolated from lecithin:cholesterol acyltransferase (LCAT)-deficient plasma. The HDL3 subfraction isolated by rate-zonal ultracentrifugation contained the major part of the cholesterol-depleting effect. HDL or HDL3 decreased CoA:cholesterol acyltransferase (ACAT) activity to 5% of the level found in control fibroblasts within 8 h of incubation. These findings suggest that ACAT activity is sensitive to a pool of intracellular cholesterol, which can be mobilized by the addition of HDL to the culture medium, and that ACAT activity is a useful measure of cholesterol efflux from cultured fibroblasts.

Cells, Cultured↗
PubMed1985

Synthesis and secretion of lipoprotein lipase by human monocyte-derived macrophages.

Human monocytes isolated from either defibrinated blood or buffy coat were shown to produce and secrete lipoprotein lipase during culture. The secretion occurred constitutively. Low levels of enzyme activity in the medium from freshly isolated cells increased with time of incubation, and maximal activity was attained after 9 days. The addition of heparin resulted in a substantial increase of enzyme activity in the culture medium. The optimal concentration of heparin was about 2 U/ml. The production of lipoprotein lipase was dependent on the presence of serum in the culture medium, and the optimal supplementation of serum was 25-50%.

Cells, Cultured↗
PubMed1984

Hemodialysis and cell toxicity in vitro related to plasma triglycerides, post-heparin lipolytic activity and free fatty acids.

Plasma triglyceride (TG) concentrations, post-heparin lipolytic activities and the free fatty acid (FFA) pattern of uremic and normal plasma were compared and correlated to plasma toxicity as measured by the effect on human mononuclear phagocytes cultured in vitro. Plasma TG concentration and FFA: albumin molar ratios were significantly higher in uremic plasma, and a correlation was found between TG concentrations prior to heparinization and post-heparin FFA concentrations. Uremic plasma toxicity was significantly correlated to increased post-heparin FFA: albumin molar ratio. The post-heparin lipoprotein lipase activity in uremic plasma collected 120 min after heparinization was higher than in normal plasma. Qualitative and quantitative experiments in vitro showed increased plasma toxicity with increasing FFA: albumin molar ratios. The proportion of unsaturated FFA in uremic post-heparin plasma increased compared to saturated FFA during incubation for 96 hours. Altered lipid metabolism after systemic heparinization thus seems to be important for the cell toxicity of uremic plasma in vitro.

Adolescent↗
PubMed1984

The effect of systemic heparinization on plasma lipoproteins and toxicity in patients on hemodialysis and continuous ambulatory peritoneal dialysis.

The lipid patterns of plasma from 6 patients on hemodialysis (HD) and 6 patients on continuous ambulatory peritoneal dialysis (CAPD) were compared and correlated to plasma toxicity as measured by the survival of human macrophages cultured in vitro. The median values for plasma triglycerides (TG), cholesterol, low density lipoprotein (LDL) cholesterol, apolipoprotein B and lipolytic activities (lipoprotein lipase and hepatic lipase) were insignificantly higher in CAPD plasma than in HD plasma. The median high density lipoprotein (HDL) cholesterol/LDL cholesterol ratio was significantly higher in HD plasma than in CAPD plasma. In both groups systemic heparinization was followed by a significant increase in free fatty acids and in plasma toxicity. The difference in plasma toxicity was insignificant. In the whole group of patients (n = 12) toxicity in post-heparin plasma was correlated to pre-heparin very low density lipoprotein (VLDL) TG, but not to LDL TG. Separately post-heparin toxicity in CAPD plasma was correlated to pre-heparin total TG, VLDL TG and post-heparin LDL TG.

Adolescent↗