‘Sciencenet’—towards a global search and share engine for all scientific knowledge

Summary: Modern biological experiments create vast amounts of data which are geographically distributed. These datasets consist of petabytes of raw data and billions of documents. Yet to the best of our knowledge, a search engine technology that searches and cross-links all different data types in life sciences does not exist

Identification by whole-genome resequencing of gene defect responsible for severe hypercholesterolemia

Whole-genome sequencing is a potentially powerful tool for the diagnosis of genetic diseases. Here, we used sequencing-by-ligation to sequence the genome of an 11-month-old breast-fed girl with xanthomas and very high plasma cholesterol levels (1023 mg/dl). Her parents had normal plasma cholesterol levels and reported no family history of hypercholesterolemia, suggesting either an autosomal recessive disorder or a de novo mutation. Known genetic causes of severe hypercholesterolemia were ruled out by sequencing the responsible genes (LDLRAP, LDLR, PCSK9, APOE and APOB), and sitosterolemia was ruled out by documenting a normal plasma sitosterol:cholesterol ratio. Sequencing revealed 3 797 207 deviations from the reference sequence, of which 9726 were nonsynonymous single-nucleotide substitutions. A total of 9027 of the nonsynonymous substitutions were present in dbSNP or in 21 additional individuals from whom complete exonic sequences were available. The 699 novel nonsynonymous substitutions were distributed among 604 genes, 23 of which were single-copy genes that each contained 2 nonsynonymous substitutions consistent with an autosomal recessive model. One gene, ABCG5, had two nonsense mutations (Q16X and R446X). This finding indicated that the infant has sitosterolemia. Thus, whole-genome sequencing led to the diagnosis of a known disease with an atypical presentation. Diagnosis was confirmed by the finding of severe sitosterolemia in a blood sample obtained after the infant had been weaned. These findings demonstrate that whole-genome (or exome) sequencing can be a valuable aid to diagnose genetic diseases, even in individual patients

Metabolic profiling in serum, cerebrospinal fluid, and brain of patients with cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is caused by autosomal recessive loss of function mutations in CYP27A1 resulting in altered bile acid and lipid metabolism. We aimed to identify metabolic aberrations that drive neurodegeneration in CTX despite chenodeoxycholic acid (CDCA) treatment. Therefore, we analyzed 26 sterol metabolites in serum and CSF of patients with CTX and in one CTX brain using chromatographic separation techniques coupled to mass spectrometry. Samples of drug naive patients were compared to patients treated with CDCA and healthy controls. We identified 7α,12α-dihydroxycholest-4-en-3-one as the most prominently elevated metabolite in serum and CSF of drug naive patients compared to controls. Standard diagnostic markers like 5α-cholestanol and 7α-hydroxycholesterol were less consistently elevated in CTX. CDCA treatment substantially reduced or even normalized levels of all metabolites increased in untreated patients with CTX. Independent of CDCA treatment, metabolites of the 27-hydroxylation pathway were almost completely absent in all patients with CTX. 27-hydroxylated metabolites accounted for ~45% of total free sterol content in CSF of healthy controls but <2% in patients with CTX. Metabolic changes in brain tissue corresponded well with findings in CSF. Interestingly, 7α,12α-dihydroxycholest-4-en-3-one and 5α-cholestanol did not exert toxicity in neuronal cell culture. In conclusion, we propose that increased 7α,12α-dihydroxycholest-4-en-3-one and lack of 27-hydroxycholesterol may be the most sensitive metabolic biomarkers of CTX. As CDCA cannot reliably prevent disease progression despite reduction of most accumulated metabolites, supplementation of 27-hydroxylated bile acid intermediates or replacement of CYP27A1 might be required to counter neurodegeneration in patients with progressive disease despite CDCA treatment

Differential effects on inhibition of cholesterol absorption by plant stanol and plant sterol esters in apoE−/− mice

Aims 'Functional foods'; supplemented with plant sterol esters (PSE) and plant stanol esters (PSA) are therapeutic options for the management of hypercholesterolaemia. However, their effects on blood monocytes, endothelial function, atherogenesis, and sterol tissue concentrations are poorly understood. Methods and results Male apoE&#8722;/&#8722; mice (n= 30) were randomized to three different diets for 6 weeks (n= 10 per group): high-cholesterol (1.25%) western-type diet (WTD), WTD + 2% PSE, and WTD + 2% PSA. Both supplements reduced serum cholesterol. WTD + PSE resulted in increased plant sterol serum concentrations and increased inflammatory Ly-6C(high) monocyte numbers. WTD + PSA increased plant stanol serum concentrations and Ly-6C-monocyte numbers, but decreased vascular superoxide release, lipid hydroperoxides, and inflammatory cytokines in aortic tissue, in plasma, and in circulating monocytes. Despite reduced serum cholesterol concentrations, both supplements impaired endothelial vasodilation compared with WTD. WTD + PSA reduced the development of atherosclerotic lesions compared with WTD alone (12.7 ± 3.7 vs. 28.3 ± 3.5%), and WTD + PSE was less effective (17.5 ± 3.7%). WTD + PSE and WTD + PSA reduced the cholesterol content in the liver, but not in the brain. However, WTD + PSE and WTD + PSA increased plant sterol and plant stanol concentrations in the liver as well as in the brain. Conclusion PSE and PSA supplementation reduced serum cholesterol, but increased plant sterol and plant stanol concentrations. Elevated levels of PSE and PSA were associated with endothelial dysfunction and increased central nervous system depositions. Atherosclerotic lesion retardation was more pronounced in WTD + PSA, coinciding with higher regenerative monocyte numbers, decreased oxidative stress, and decreased inflammatory cytokines compared with WTD + PSE

Effect of onion and beet on plasma and liver lipids, platelet aggregation, and erythrocyte Na efflux in simvastatin treated hypercholesterolmic rats

This study was purposed to investigate the effect of onion or beet on plasma and liver lipids, erythrocyte Na efflux channels and platelet aggregation in simvastatin (SIM) treated hypercholesterolemic rats. Forty Sprague Dawley rats were divided into four groups and fed 0.5% cholesterol based diets containing 2 mg/kg BW simvastatin or simvastatin with 5% onion or beet powder. Plasma total cholesterol was significantly increased in SIM group compared with the control (p<0.01), and the elevated plasma total cholesterol of SIM group was significantly decreased in SIM-onion and SIM-beet groups (p<0.05). HDL-cholesterol in SIM-beet group was significantly increased compared with other groups (p<0.05). Platelet aggregation in both the maximum and initial slope was significantly decreased in SIM group compared with SIM-onion group (p<0.05). Na-K ATPase was significantly decreased in SIM group compared with the control, SIM-onion and SIM-beet groups (p<0.05). Na passive leak was significantly increased in all groups treated with SIM compared with the control (p<0.05). The total Na efflux was decreased in SIM group and increased in SIM-onion group and the difference between these two groups was significant (p<0.05). There was no difference in intracellular Na among groups. In present study, simvastatin, a HMG CoA reductase inhibitor at dose of 2mg/kg BW/day rather increased plasma total cholesterol in rats, inferring that the action mechanism of simvastatin on cholesterol metabolism differ between rat and human. Onion and beet play favorable roles in cardiovascular system by restoring the reduced Na efflux through Na-K ATPase and Na-K cotransport in SIM treated rats

Susceptibilidade antifúngica em biofilme de Candida isolada a partir da urina pacientes ambulatoriais

Background and Objectives: the association between the biofilm formations an antifungal resistance has been suggested to be an important factor in the pathogenesis of several Candida species. Besides, studies have included invasive candidiasis from hospitalized patients; however there are few studies that evaluated the species distribution, antifungal susceptibility and biofilm formation of Candida species isolated from ambulatory patients. Thus, the aim of this study was to evaluate whether biofilm producing contributes to antifungal resistance in Candida isolates from urine sample obtained from ambulatory patients. Methods: During one year, 25 urine samples positive for yeast were collected, stored and plated on agar supplemented with chloramphenicol and Sabouread left at room temperature for 5 days for subsequent: 52% (13/25) were C. albicans, 36% (9/25) C. tropicalis, 8% (2/25) C. krusei and 4% (1/25) C. parapsilosis. Results: The ability to form biofilm was detected in 23 (92%) of the yeast studied and 15.4% (2/13) of C. albicans were fluconazole (FLU) and ketoconazole (KET) resistant, while 11.1% (1/9) of C. tropicalis were ketoconazole resistant and were anidulafungin (ANI) non-susceptible. Conclusion: our results showed the high capacity for biofilm formation among Candida isolates from ambulatory patients.Justificativa e objetivos: a associação entre as formações biofilme uma resistência antifúngica foi sugerido para ser um fator importante na patogênese de diversas espécies de Candida. Além disso, estudos têm incluído candidíase invasiva de pacientes hospitalizados; no entanto, existem poucos estudos que avaliaram a distribuição das espécies, suscetibilidade aos antifúngicos e formação de biofilme de espécies de Candida isoladas de pacientes ambulatoriais. Assim, o objetivo deste estudo foi avaliar se a produção de biofilme contribui para a resistência antifúngica em Candida isoladas de amostras de urina obtidas de pacientes de ambulatório. Métodos: Durante um ano, 25 amostras de urina positivas para leveduras, foram coletadas, armazenadas e semeadas em agar Sabouread suplementado com cloranfenicol e deixadas a temperature ambiente por 5 dias, para posterior identificação: 52% (13/25) foram C. albicans, 36% (9/25) C. tropicalis, 8% (2/25) C. krusei e 4% ( 1/25) C. parapsilosis. Resultados: A capacidade de formar biofilme foi detectada em 23 (92%) da levedura estudados e 15,4% (2/13) de C. albicans foram fluconazol (FLU) e cetoconazol (PET) resistente, enquanto que 11,1% (1/9 ) de C. tropicalis foram resistentes cetoconazol e foram anidulafungina (ANI) não-suscetíveis. Conclusão: nossos resultados mostraram a alta capacidade de formação de biofilme entre Candida isoladas de pacientes ambulatoriais. Conclusão: nossos resultados mostraram a alta capacidade de formação de biofilme entre Candida isoladas de pacientes ambulatoriais

Cerebral Accumulation of Dietary Derivable Plant Sterols does not Interfere with Memory and Anxiety Related Behavior in Abcg5−/− Mice

Plant sterols such as sitosterol and campesterol are frequently applied as functional food in the prevention of atherosclerosis. Recently, it became clear that plasma derived plant sterols accumulate in murine brains. We questioned whether plant sterols in the brain are associated with alterations in brain cholesterol homeostasis and subsequently with brain functions. ATP binding cassette (Abc)g5−/− mice, a phytosterolemia model, were compared to Abcg5+/+ mice for serum and brain plant sterol accumulation and behavioral and cognitive performance. Serum and brain plant sterol concentrations were respectively 35–70-fold and 5–12-fold increased in Abcg5−/− mice (P < 0.001). Plant sterol accumulation resulted in decreased levels of desmosterol (P < 0.01) and 24(S)-hydroxycholesterol (P < 0.01) in the hippocampus, the brain region important for learning and memory functions, and increased lanosterol levels (P < 0.01) in the cortex. However, Abcg5−/− and Abcg5+/+ displayed no differences in memory functions or in anxiety and mood related behavior. The swimming speed of the Abcg5−/− mice was slightly higher compared to Abcg5+/+ mice (P < 0.001). In conclusion, plant sterols in the brains of Abcg5−/− mice did have consequences for brain cholesterol metabolism, but did not lead to an overt phenotype of memory or anxiety related behavior. Thus, our data provide no contra-indication for nutritional intake of plant sterol enriched nutrition