Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Cardiovascular drug reviews 20 (2002), S. 0 
    ISSN: 1527-3466
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Sitosterolemia was first described 28 years ago in two sisters. They had tendon xanthomas, normal plasma cholesterol levels, and elevated plant sterol levels. The high plant sterol levels were shown to be due to the increased absorption and delayed removal of plant sterols from the body. The increased absorption of plant sterols does not affect cholesterol absorption in these patients. However, cholesterol biosynthesis pathway is downregulated and turnover rates are reduced. Bile acid binding resins and ileal bypass surgery are effective treatments for sitosterolemic patients, whereas statins are ineffective. Sitosterolemia is inherited as a recessive trait. Recent studies have shown that mutations in ABCG5 and ABCG8 genes contribute to sitosterolemia. Most likely, ABCG5 and ABCG8 proteins function as obligate heterodimers and play a role in the absorption of plant sterol or control their rate of absorption.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Familial hypercholanemia (FHC) is characterized by elevated serum bile acid concentrations, itching, and fat malabsorption. We show here that FHC in Amish individuals is associated with mutations in tight junction protein 2 (encoded by TJP2, also known as ZO-2) and bile acid Coenzyme A: amino acid ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inherited metabolic disease 19 (1996), S. 391-400 
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the enzyme defects in two inherited disorders of cholesterol biosynthesis: sitosterolaemia and the Smith-Lemli-Opitz syndrome. In sitosterolaemic homozygotes, plasma plant sterols (sitosterol and campesterol) concentrations are elevated because of enhanced intestinal absorption and diminished removal. Underlying these changes is very low cholesterol biosynthesis to provide extra sterol for cell growth. Extremely reduced activities of HMG-CoA reductase, the rate-controlling enzyme for cholesterol biosynthesis, caused by deficient HMG-CoA reductase mRNA is responsible and is the suspected inherited abnormality. The Smith-Lemli-Opitz syndrome is caused by a block in the last reaction in the cholesterol biosynthetic pathway, the conversion of 7-dehydrocholesterol to cholesterol, which is catalysed by 7-dehydrocholesterol Δ7-reductase. As a result, low plasma and tissue cholesterol with high 7-dehydrocholesterol levels are found in homozygotes, who show characteristic phenotypes of mental retardation, facial dysmorphism, and organ and limb congenital anomalies. Similar biochemical findings are produced in rats fed BM 15,766, an inhibitor of 7-dehydrocholesterol Δ7-reductase. Interestingly, feeding cholesterol can suppress abnormal cholesterol biosynthesis and improve symptoms in homozygotes and rats fed BM 15,766.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The Smith–Lemli–Opitz syndrome (SLOS) is a recessively inherited birth disorder caused by a defect in 7-dehydrocholesterol (3β-hydroxysteroid) Δ7-reductase, the final enzyme in cholesterol biosynthesis. To investigate in vivo regulation of the cholesterol biosynthetic pathway in SLOS, we measured hepatic microsomal sterol concentrations and activities of several key enzymes in the pathway, including HMG-CoA synthase, HMG-CoA reductase, squalene synthase and 7-dehydrocholesterol Δ7-reductase in liver specimens from a patient with SLOS and 11 controls. Hepatic microsomal 7-dehydrocholesterol Δ7-reductase activity in the patient was less than 1% of the control mean, and decreased cholesterol concentration and markedly increased 7- and 8-dehydrocholesterol concentrations were observed in the patient's microsomes. HMG-CoA synthase and squalene synthase activities in the patient were upregulated to 149% and 532%, respectively, while the activity of HMG-CoA reductase, the rate-limiting enzyme in the pathway, was reduced to 39% of the control mean. Downregulation of HMG-CoA reductase activity in SLOS was supported by measuring plasma levels of mevalonic acid, the immediate product of HMG-CoA reductase. The levels in SLOS patients (n=9) were significantly low compared with age-matched controls (n=8) (12±2 vs 28±6 nmol/L, p〈0.05). These results suggest that in most SLOS patients in vivo HMG-CoA reductase is not stimulated in spite of blocked cholesterol biosynthetic pathway and reduced plasma and hepatic cholesterol concentrations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The activity of ergosterol Δ7-reductase (3β-hydroxysteroid Δ7-reductase) was measured in cultured skin fibroblasts from 7 controls, 10 Smith–Lemli–Opitz syndrome (SLOS) patients, and 10 parents (obligate carriers). The fibroblasts were exposed to delipidated medium supplemented with lovastatin for 24h and the enzyme activity was determined by incubating cell-free homogenate with ergosterol (ergosta-5,7,22-trien-3β-ol) and measuring the mass of brassicasterol (ergosta-5,22-dien-3β-ol) formed by gas chromatography–mass spectrometry with selected-ion monitoring. In carriers, the activity was significantly lower than in controls (22±2 vs 65±10 pmol/min per mg protein, p〈0.0005), and no overlap was observed. The mean activity in carriers' fibroblasts was more than 100 times higher than in patients' cells (0.2 pmol/min per mg protein). The use of ergosterol avoids the many problems caused by the instability and lack of availability of radiolabelled 7-dehydrocholesterol. The present method makes it possible to discriminate SLOS carriers from both controls and patients using a commercially available substrate and common analytical equipment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Niemann–Pick disease type C (NP-C) is a rare genetic disorder characterized by progressive neurodegeneration, frequent developmental delay and early death. Tissues of affected individuals accumulate large quantities of free cholesterol in lysosomes. Because cytotoxic oxygenated derivatives of cholesterol are known to form readily when cholesterol concentrations are elevated, we searched for these compounds in liver, kidney, spleen and brain from mice with the NP-C phenotype. In order of abundance, we identified 7α- and 7β-hydroxycholesterol, 5α,6α-epoxycholestan-3β-ol, 4β-hydroxycholesterol, cholest-4-en-3β,7α-diol and cholest-4-en-3β,6β-diol in most tissue samples. Cholesterol concentrations in affected mice were increased 3-fold in kidney and 7- to 8-fold in spleen and liver compared to controls (all p〈0.001) but were unchanged in brain. Although oxysterol levels were markedly elevated in non-brain tissue, the oxysterol and cholesterol concentrations increased proportionally so that oxysterols expressed as percentage of total sterols were the same for all animals (0.34±0.19% averaged over all organs in affected animals vs 0.40±0.42% in control mice). In contrast to peripheral tissue, we could not detect any increase in either absolute or relative oxysterol levels in the brains of affected and control mice (49±61 vs 53±43 μg/g wet weight and 0.45±0.52 vs 0.47±0.37%, respectively). Thus, brain sterols are normal in NP-C mice and it is unlikely that an accumulation of cytotoxic oxygenated derivatives of cholesterol could account for the progressive neuropathology seen in the disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...