GM kaasuttimen käsikirja tyyppi GMSF-V

kuv., 14 x 20 cm

GM kaasuttimen käsikirja tyyppi GMSF-O

kuv., 14 x 20 cm

GM kemiallisen öljynpuhdistimen asennusohjeita

kuv., 14 x 22 cm

Uusikaa Chevrolet moottorinne uutta GM järjestelmää hyväksikäyttäen

kuv., 15 x 22 cm

Role of Membrane Transporters, P-Glycoprotein and Mrp1, in The Placental Transfer of Drugs With Special Reference to Saquinavir and Quetiapine

Drug transporting membrane proteins are expressed in various human tissues and blood-tissue barriers, regulating the transfer of drugs, toxins and endogenous compounds into or out of the cells. Various in vitro and animal experiments suggest that P-glycoprotein (P-gp) forms a functional barrier between maternal and fetal blood circulation in the placenta thereby protecting the fetus from exposure to xenobiotics during pregnancy. The multidrug resistance-associated protein 1 (MRP1) is a relatively less studied transporter protein in the human placenta. The aim of this study series was to study the role of placental transporters, apical P-gp and basal MRP1, using saquinavir as a probe drug, and to study transfer of quetiapine and the role of P-gp in its transfer in the dually perfused human placenta/cotyledon. Furthermore, two ABCB1 (encoding P-gp) polymorphisms (c.3435C>T, p.Ile1145Ile and c.2677G>T/A, p.Ala893Ser/Thr) were studied to determine their impact on P-gp protein expression level and on the transfer of the study drugs. Also, the influence of the P-gp protein expression level on the transfer of the study drugs was addressed. Because P-gp and MRP1 are ATP-dependent drug-efflux pumps, it was studied whether exogenous ATP is needed for the function of ATP-dependent transporter in the present experimental model. The present results indicated that the addition of exogenous ATP was not necessary for transporter function in the perfused human placental cotyledon. Saquinavir and quetiapine were both found to cross the human placenta; transplacental transfer (TPTAUC %) for saquinavir was <0.5% and for quetiapine 3.7%. Pharmacologic blocking of P-gp led to disruption of the blood-placental barrier (BPB) and increased the placental transfer of P-gp substrate, saquinavir, into the fetal circulation by 6- to 8-fold. In reversed perfusions P-gp, MRP1 and possibly OATP2B1 had a negligible role in the fetal-to-maternal transfer of saquinavir. The TPTAUC % of saquinavir was about 100-fold greater from the fetal side to the maternal side compared with the maternal-to-fetal transfer. P-gp activity is not likely to modify the placental transfer of quetiapine. Higher P-gp protein expression levels were associated with the variant allele 3435T, but no correlation was found between the TPTAUC % of saquinavir and placental P-gp protein expression. The present results indicate that P-gp activity drastically affects the fetal exposure to saquinavir, and suggest that pharmacological blockade of the P-gp activity during pregnancy may pose an increased risk for adverse fetal outcome. The blockade of P-gp activity could be used in purpose to obtain higher drug concentration to the fetal side, for example, in prevention (to decrease virus transfer to fetal side) or in treating sick fetus.

Morphometric Study of Cerebral Arterioles in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy(CADASIL) is the most common hereditary small vessel disease (SVD) leading to vascular dementia. The cause of the disease is mutations in NOTCH3 gene located at chromosome 19p13.1. The gene defect results in accumulation of granular osmiophilic material and extracellular domain of NOTCH3 at vascular smooth muscle cells (VSMCs) with subsequent degeneration of VSMCs. This arteriopathy leads to white matter (WM) rarefaction and multiple lacunar infarctions in both WM and deep grey matter (GM) visible in magnetic resonance imaging. This thesis is focused on the quantitative morphometric analysis of the stenosis and fibrosis in arterioles of the frontal cerebral WM, cortical GM and deep GM (lenticular nucleus (LN), i.e. putamen and globus pallidus). It was performed by assessing four indicators of arteriolar stenosis and fibrosis: (1) diameter of arteriolar lumen, (2) thickness of arteriolar wall, (3) external diameter of arterioles and (4) sclerotic index. These parameters were assessed (a) in 5 elderly CADASIL patients with the mean age of onset 47 years and of death 63 years, (b) in a 32-year-old young CADASIL patient with the first ischemic episode at the age of 29 years and (c) a very old CADASIL patient aged 95 years, who suffered the first stroke at the age of 71 years. These measurements were compared with age-matched controls without stroke, dementia, hypertension, and cerebral amyloid angiopathy. Morphometric analyses disclosed that in all age groups of CADASIL patients compared to corresponding controls there was significant narrowing of arteriolar lumen (stenosis) and fibrotic thickening of the walls (fibrosis) in the WM arterioles, although the significance of stenosis in the very old patient was marginal. In the LN arterioles there was only significant fibrosis without stenosis. These results suggest that the ischemic lesions and lacunar infarcts in the cerebral WM are mainly attributable to the stenosis of arterioles, whereas those in the LN are probably mainly due to hemodynamic changes of the cerebral blood flow. In conclusion: The SVD of CADASIL is characterized by narrowing of lumina and fibrotic thickening of walls predominantly in the cerebral WM arterioles. On the other hand, in the LN the ischemic lesions and lacunar infarcts are most probably hemodynamic due to impaired autoregulation caused by the rigidity of fibrotic arterioles. The pathological cerebral arteriolar alterations begin to develop already at a relatively young age but the onset may be delayed to a remarkably old age. This underlines the well known great variability in the clinical picture of CADASIL. The very late onset of CADASIL may cause its underdiagnosis, because the strokes are common in the elderly and are attributed to common risk factors.

Gut Microbiota and Metabolic Disorders

Obesity and its co-morbidities, such as metabolic syndrome (MetS), non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes, have increased over the last few decades like an epidemic. So far the mechanisms of many metabolic diseases are not known in detail and currently there are not enough effective means to prevent and treat them. Several recent studies have shown that the unbalanced gut microbiota composition (GMC) and activity have an influence on the fat accumulation in the body. Further, it seems that the GMC of obese individuals differs from the lean. The aim of this study was to investigate whether there are differences between the GMC of metabolically impaired overweight/obese (MetS group), metabolically healthy overweight/obese and normal-weight individuals. In addition, the mechanisms by which the gut bacteria as well as their specific structures, such as flagellin (FLG) that stimulates the Toll-like receptor 5 (TLR5) affect metabolism, were investigated both in vivo and in vitro in human adipocytes and hepatocytes. The results of this study show that the abundance of certain gram-positive bacteria belonging to the Clostridial cluster XIV was higher in the MetS group subjects compared to their metabolically healthy overweight/obese and lean counterparts. Metabolically impaired subjects tended to also have a greater abundance of potentionally inflammatory Enterobacteria in their gut and thus seemed to have aberrant GMC. In addition, it was found that subjects with a high hepatic fat content (HHFC group) had less Faecalibacterium prausnitzii in their gut than individuals with low hepatic fat content. Further gene expression analysis revealed that the HHFC group also had increased inflammation cascades in their adipose tissue. Additionally, metabolically impaired individuals displayed an increased expression of FLG-recognizing TLR5 in adipose tissue, and the TLR5 expression levels associated positively both with liver fat content and insulin resistance in humans. These changes in the adipose tissue may further contribute to the impaired metabolism observed, such as insulin resistance and dyslipidemia. In vitro -studies showed that the FLG-induced TLR5 activation in adipocytes enhanced the hepatic fat accumulation by decreasing insulin signaling and mitochondrial functions and increasing triglyceride synthesis due to increased glycerol secretion from adipocytes. In conclusion, the findings of this study suggest that it may be possible that the novel prevention and personalized treatment strategies based on GM modulation will succesfully be developed for obesity and metabolic disorders in the future.