Water stress induced alterations in ornithine aminotransferase of ragi (Eleusine coracana): Protection by proline against heat inactivation and denaturation by urea and guanidinium chloride

Water stress resulted in a specific response leading to a large and significant increase (80-fold) in free proline content of ragi (Eleusine coracana) leaves and seedlings. L-Proline protected ornithine aminotransferase, an enzyme in the pathway for proline biosynthesis, isolated from normal and stressed ragi leaves against heat inactivation and denaturation by urea and guanidinium chloride. The protection of the stressed enzyme by L-proline was much more complete than that of the enzyme isolated from normal leaves. While L-ornithine, one of the substrates, protected the stressed enzyme against inactivation, it enhanced the rate of inactivation of the normal enzyme. α-Ketoglutarate protected both the normal and stressed enzyme against inactivation and denaturation. These results support the suggestion that ornithine aminotransferase has undergone a structural alteration during water stress. In view of the causal relationship between elevated temperature and water stress of plants under natural conditions, the protection afforded by proline against inactivation and denaturation of the enzyme from stressed leaves assumes significance. These results provide an explanation for a possible functional importance of proline accumulation during water stress.

Ambient temperature and risk of cardiovascular hospitalization: An updated systematic review and meta-analysis

The association between temperatures and risk of cardiovascular mortality has been recognized but the association drawn from previous meta-analysis was weak due to the lack of sufficient studies. This paper presented a review with updated reports in the literature about the risk of cardiovascular hospitalization in relation to different temperature exposures and examined the dose–response relationship of temperature-cardiovascular hospitalization by change in units of temperature, latitudes, and lag days. The pooled effect sizes were calculated for cold, heat, heatwave, and diurnal variation using random-effects meta-analysis, and the dose–response relationship of temperature-cardiovascular admission was modelled using random-effect meta-regression. The Cochrane Q-test and index of heterogeneity (I2) were used to evaluate heterogeneity, and Egger's test was used to evaluate publication bias. Sixty-four studies were included in meta-analysis. The pooled results suggest that for a change in temperature condition, the risk of cardiovascular hospitalization increased 2.8% (RR, 1.028; 95% CI, 1.021–1.035) for cold exposure, 2.2% (RR, 1.022; 95% CI, 1.006–1.039) for heatwave exposure, and 0.7% (RR, 1.007; 95% CI, 1.002–1.012) for an increase in diurnal temperature. However no association was observed for heat exposure. The significant dose–response relationship of temperature — cardiovascular admission was found with cold exposure and diurnal temperature. Increase in one-day lag caused a marginal reduction in risk of cardiovascular hospitalizations for cold exposure and diurnal variation, and increase in latitude was associated with a decrease in risk of cardiovascular hospitalizations for diurnal temperature only. There is a significant short-term effect of cold exposure, heatwave and diurnal variation on cardiovascular hospitalizations. Further research is needed to understand the temperature-cardiovascular relationship for different climate areas.

Unusual structural stability and ligand induced alterations in oligomerization of a galectin

Abstract L-14, a 14-kDa S-type lectin shows the jelly roll tertiary structural fold akin to legume lectins yet, unlike them, it does not dissociate on thermal unfolding. In the absence of ligand L-14 displays denaturation transitions corresponding to tetrameric and octameric entities. The presence of complementary ligand reduces the association of L-14, which is in stark contrast with legume lectins where no alterations in quaternary structures are brought about by saccharides. From the magnitude of the increase in denaturation temperature induced by disaccharides the binding constants calculated from differential scanning calorimetry are comparable with those extrapolated from titration calorimetry indicating that L-14 interacts with ligands essentially in the folded state.

Thyroid Hormone Control of Cardiac Substrate Metabolism

Thyroid hormone (TH) plays an important role in maintaining a homeostasis in all the cells of our body. It also has significant cardiovascular effects, and abnormalities of its concentration can cause cardiovascular disease and even morbidity. Especially development of heart failure has been connected to low levels of thyroid hormone. A decrease in TH levels or TH-receptor binding adversely effects cardiac function. Although, this occurs in part through alterations in excitation-contraction and transport proteins, recent data from our laboratory indicate that TH also mediates changes in myocardial energy metabolism. Thyroid dysfunction may limit the heart s ability to shift substrate pathways and provide adequate energy supply during stress responses. Our goals of these studies were to determine substrate oxidation pattern in systemic and cardiac specific hypothyroidism at rest and at higher rates of oxygen demand. Additionally we investigated the TH mediated mechanisms in myocardial substrate selection and established the metabolic phenotype caused by a thyroid receptor dysfunction. We measured cardiac metabolism in an isolated heart model using 13Carbon isotopomer analyses with MR spectroscopy to determine function, oxygen consumption, fluxes and fractional contribution of acetyl-CoA to the citric acid cycle (CAC). Molecular pathways for changes in cardiac function and substrate shifts occurring during stress through thyroid receptor abnormalities were determined by protein analyses. Our results show that TH modifies substrate selection through nuclear-mediated and rapid posttranscriptional mechanisms. It modifies substrate selection differentially at rest and at higher rates of oxygen demand. Chronic TH deficiency depresses total CAC flux and selectively fatty acid flux, whereas acute TH supplementation decreases lactate oxidation. Insertion of a dominant negative thyroid receptor (Δ337T) alters metabolic phenotype and contractive efficiency in heart. The capability of the Δ337T heart to increase carbohydrate oxidation in response to stress seems to be limited. These studies provided a clearer understanding of the TH role in heart disease and shed light to identification of the molecular mechanisms that will facilitate in finding targets for heart failure prevention and treatment.

Molecular Alterations in Asbestos-Related Lung Cancer

Background: Asbestos is a well known cancer-causing mineral fibre, which has a synergistic effect on lung cancer risk in combination with tobacco smoking. Several in vitro and in vivo experiments have demonstrated that asbestos can evoke chromosomal damage and cause alterations as well as gene expression changes. Lung tumours, in general, have very complex karyotypes with several recurrently gained and lost chromosomal regions and this has made it difficult to identify specific molecular changes related primarily to asbestos exposure. The main aim of these studies has been to characterize asbestos-related lung cancer at a molecular level. Methods: Samples from asbestos-exposed and non-exposed lung cancer patients were studied using array comparative genomic hybridization (aCGH) and fluorescent in situ hybridization (FISH) to detect copy number alterations (CNA) as well as microsatellite analysis to detect allelic imbalance (AI). In addition, asbestos-exposed cell lines were studied using gene expression microarrays. Results: Eighteen chromosomal regions showing differential copy number in the lung tumours of asbestos-exposed patients compared to those of non-exposed patients were identified. The most significant differences were detected at 2p21-p16.3, 5q35.3, 9q33.3-q34.11, 9q34.13-q34.3, 11p15.5, 14q11.2 and 19p13.1-p13.3 (p<0.005). The alterations at 2p and 9q were validated and characterized in detail using AI and FISH analysis in a larger study population. Furthermore, in vitro studies were performed to examine the early gene expression changes induced by asbestos in three different lung cell lines. The results revealed specific asbestos-associated gene expression profiles and biological processes as well as chromosomal regions enriched with genes believed to contribute to the common asbestos-related responses in the cell lines. Interestingly, the most significant region enriched with asbestos-response genes was identified at 2p22, close to the previously identified region showing asbestos-related CNA in lung tumours. Additionally, in this thesis, the dysregulated biological processes (Gene Ontology terms) detected in the cell line experiment were compared to dysregulated processes identified in patient samples in a later study (Ruosaari et al., 2008a). Commonly affected processes such as those related to protein ubiquitination, ion transport and surprisingly sensory perception of smell were identified. Conclusions: The identification of specific CNA and dysregulated biological processes shed some light on the underlying genes acting as mediators in asbestos-related lung carcinogenesis. It is postulated that the combination of several asbestos-specific molecular alterations could be used to develop a diagnostic method for the identification of asbestos-related lung cancer.

Hormone therapy in elderly women; a comparative study with alendronate of the effects on bone, cardiovascular risk factors, periodontal conditions and quality of life

Thirty percent of 70-year-old women have osteoporosis; after age of 80 its prevalence is up to 70%. Postmenopausal women with osteoporosis seem to be at an increased risk for cardiovascular events, and deterioration of oral health, as shown by attachment loss of teeth, which is proportional to the severity of osteoporosis. Osteoporosis can be treated with many different medication, e.g. estrogen and alendronate. We randomized 90 elderly osteoporotic women (65-80 years of age) to receive hormone therapy (HT)(2mg E2+NETA), 10mg alendronate, and their combination for two years and compared their effects on bone mineral density (BMD) and turnover, two surrogate markers of the risk of cardiovascular diseases, C-reactive protein (CRP) and E-selectin, as well as oral health. The effect of HT on health-related quality of life (HRQoL) was studied in the population-based cohort of 1663 postmenopausal women (mean age 68 yr) (585 estrogen users and 1078 non-users). BMD was measured with dual-energy X-ray absorptiometry (DXA) at 0, 12 and 24 months. Urinary N-telopeptide (NTX) of type I collagen, a marker of bone resorption, and serum aminoterminal propeptide of human type I procollagen (PINP), a marker of bone formation, were measured every six months of treatment. Serum CRP and E-selectin, were measured at 0, 6, and 12 months. Dental, and periodontal conditions, and gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-8 levels were studied to evaluate the oral health status and for the mouth symptoms a structured questionnaire was used. The HRQoL was measured with 15D questionnaire. Lumbar spine BMD increased similarly in all treatment groups (6.8-8.4% and 9.1-11.2%). Only HT increased femoral neck BMD at both 12 (4.9%) and 24 months (5.8%), at the latter time point the HT group differed significantly from the other groups. HT reduced bone marker levels of NTX and PINP significantly less than other two groups.Oral HT significantly increased serum CRP level by 76.5% at 6 and by 47.1% (NS) at 12 months, and decreased serum E-selectin level by 24.3% and 30.0%. Alendronate had no effect on these surrogate markers. Alendronate caused a decrease in the resting salivary flow rate and tended to increase GCF MMP-8 levels. Otherwise, there was no effect on the parameters of oral health. HT improved the HRQoL of elderly women significantly on the dimensions of usual activities, vitality and sexual activity, but the overall improvement in HRQoL was neither statistically significant nor clinically important. In conclusion, bisphosphonates might be the first option to start the treatment of postmenopausal osteoporosis in the old age.

The Impact of Lifestyle and Cardiovascular Risk Factors in Midlife on the Health-Related Quality of Life among Old Men

Prevention of cardiovascular diseases is known to postpone death, but in an aging society it is important to ensure that those who live longer are neither disabled nor suffering an inferior quality of life. It is essential both from the point of view of the aging individual as well as that of society that any individual should enjoy a good physical, mental and social quality of life during these additional years. The studies presented in this thesis investigated the impact of modifiable risk factors, all of which affect cardiovascular health in the long term, on mortality and health-related quality of life (HRQoL). The data is based on the all male cohort of the Helsinki Businessmen Study. This cohort, originally of 3.490 men born between 1919 and 1934 has been followed since the 1960s. The socioeconomic status of the participants is similar, since all the men were working in leading positions. Extensive baseline examinations were conducted among 2.375 of the men in 1974 when their mean age was 48 and at this time the health, medication and cardiovascular risk factors of the participants were observed. In 2000, at the mean age of 73, the HRQoL of the survivors of the original cohort was examined using the RAND-36 mailed questionnaire (n=1.864). RAND-36, along with the equivalent SF-36, is the world s most widely used means of assessing generic health. The response rate was generally over 90%. Mortality was retrieved from national registers in 2000 and 2002. For the six substudies of this thesis, the impact of four different modifiable cardiovascular risk factors (weight gain, cholesterol, alcohol and smoking) on the HRQoL in old age was studied both independently and in combination. The follow-up time for these studies varies from 26 up to 39 years. Mortality is reported separately or included in the RAND-36 scores for HRQoL. Elevated levels of all the risk factors examined among the participants in midlife led to a diminished life expectancy. Among survivors, lower weight gain in midlife was associated with better HRQoL, both physically and mentally. Higher levels of serum cholesterol in middle age indicated both an earlier mortality and a decline in the physical component of HRQoL in a dose-response manner during the 39-year follow-up. Mortality was significantly higher in the highest baseline category of reported mean alcohol consumption (≥ 5 drinks/day), but fairly comparable in abstainers and moderate drinkers during the 29-year follow-up. When HRQoL in old age was accounted for mortality, the men with the highest alcohol consumption in midlife clearly had poorer physical and mental health in old age, but the HRQoL of abstainers and those who drank alcohol in moderation were comparatively similar. The amount of cigarette smoking in midlife was shown to have had a dose-response effect on both mortality and HRQoL in old age during the 26 year follow-up. The men smoking over 20 cigarettes daily in middle age lost about 10 years of their life-expectancy. Meanwhile, the physical functioning of surviving heavy smokers in old age was similar to men 10 years older in the general population. The impact of clustered cardiovascular risk factors was examined by comparing two subcohorts of men who were healthy in 1974, but with different baseline risk factor status. The men with low risk had a 50 % lower mortality during the 29-years follow-up. Their RAND-36 scores for the physical quality of life in old age were significantly better, and the 2002 questionnaire examining psychological well-being indicated also significantly better mental health among the low-risk group. The results indicate that different risk factor levels in midlife have a meaningful impact on life-expectancy and the quality of these extra years. Leading a healthy lifestyle improves both survival and the quality of life.

Kallikrein-related peptidase 4 induces tumour microenvironment alterations that support tumour growth

Kallikrein-related peptidase 4 (KLK4) is a protease with elevated production in prostate cancer versus benign tissue. KLK4 expression is associated with prostate cancer risk, and its activity favours tumour progression through increasing cell motility and growth. Importantly, over-production of KLK4 in prostate glandular cells precedes tumour formation, positioning the enzyme to play a role in early remodelling of the tumour microenvironment, a process essential for tumour growth. We sought to identify the proteins and downstream signalling pathways targeted by KLK4 activity, to define its role in tumour microenvironment remodelling and evaluate the efficacy of KLK4 inhibition as a cancer therapy.

Long-term effects of fenofibrate on lipoproteins and surrogate markers of macrovascular and microvascular disease in people with type 2 diabetes

Background and aims. Diabetic dyslipidemia is a highly atherogenic triad of increased triglycerides, decreased HDL cholesterol, and small dense LDL. Fibrates have a beneficial effect on diabetic dyslipidemia, and they have reduced cardiovascular events in randomized trials. Fenofibrate has reduced albuminuria and markers of low-grade inflammation and endothelial dysfunction. The present studies were undertaken to characterize the alterations of VLDL and LDL subclasses and to investigate the binding of LDL to arterial wall in type 2 diabetes. Further purpose was to elucidate the effects of fenofibrate on several lipoprotein subclasses, augmentation index (AIx), carotid intima-media thickness (IMT), and renal function. Subjects. 239 type 2 diabetic subjects were recruited among participants of the FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) study at the Helsinki centre. The patients were randomized to fenofibrate (200mg/d) or placebo for 5 years. Additionally, a healthy control group (N = 93) was recruited. Results. VLDL1 triglycerides increased in similar proportion to total triglycerides in type 2 diabetic patients and control subjects. Despite the increase in total apoCIII levels, VLDL apoCIII was decreased in diabetic patients. Enrichment of LDL with apoCIII induced a small increase in binding of LDL to arterial wall proteoglycan. Intrinsic characteristics of diabetic LDL, rather than levels of apoCIII, were responsible for increased proteoglycan binding of diabetic LDL with high apoCIII. Fenofibrate reduced triglycerides, increased LDL size, and shifted HDL subclasses towards smaller particles with no change in levels of HDL cholesterol. High levels of homocysteine were associated with lower increase of HDL cholesterol and apoA-I during fenofibrate treatment. Long-term fenofibrate treatment did not improve IMT, AIx, inflammation, or endothelial function. Fenofibrate decreased creatinine clearance and estimated glomerular filtration rate. No effect on albuminuria was seen with fenofibrate. Instead, Cystatin C was increased during fenofibrate treatment. Conclusions. 1) Elevation of VLDL 1 triglycerides was the major determinant of plasma triglyceride concentration in control subjects and type 2 diabetic patients. 2) LDL with high apoCIII showed multiple atherogenic properties, that were only partially mediated by apoCIII per se in type 2 diabetes 3) Fenofibrate demonstrated no effect on surrogate markers of atherosclerosis. 4) Fenofibrate had no effect on albuminuria and the observed decrease in markers of renal function could complicate the clinical surveillance of the patients. 5) Fenofibrate can be used to treat severe hypertriglyceridemia or in combination therapy with statins, but not to increase HDL levels.

Effects of Metabolic Risk Factors and Type 1 Diabetes on Brain Glucose and Brain Metabolites

The metabolic syndrome and type 1 diabetes are associated with brain alterations such as cognitive decline brain infarctions, atrophy, and white matter lesions. Despite the importance of these alterations, their pathomechanism is still poorly understood. This study was conducted to investigate brain glucose and metabolites in healthy individuals with an increased cardiovascular risk and in patients with type 1 diabetes in order to discover more information on the nature of the known brain alterations. We studied 43 20- to 45-year-old men. Study I compared two groups of non-diabetic men, one with an accumulation of cardiovascular risk factors and another without. Studies II to IV compared men with type 1 diabetes (duration of diabetes 6.7 ± 5.2 years, no microvascular complications) with non-diabetic men. Brain glucose, N-acetylaspartate (NAA), total creatine (tCr), choline, and myo-inositol (mI) were quantified with proton magnetic resonance spectroscopy in three cerebral regions: frontal cortex, frontal white matter, thalamus, and in cerebellar white matter. Data collection was performed for all participants during fasting glycemia and in a subgroup (Studies III and IV), also during a hyperglycemic clamp that increased plasma glucose concentration by 12 mmol/l. In non-diabetic men, the brain glucose concentration correlated linearly with plasma glucose concentration. The cardiovascular risk group (Study I) had a 13% higher plasma glucose concentration than the control group, but no difference in thalamic glucose content. The risk group thus had lower thalamic glucose content than expected. They also had 17% increased tCr (marker of oxidative metabolism). In the control group, tCr correlated with thalamic glucose content, but in the risk group, tCr correlated instead with fasting plasma glucose and 2-h plasma glucose concentration in the oral glucose tolerance test. Risk factors of the metabolic syndrome, most importantly insulin resistance, may thus influence brain metabolism. During fasting glycemia (Study II), regional variation in the cerebral glucose levels appeared in the non-diabetic subjects but not in those with diabetes. In diabetic patients, excess glucose had accumulated predominantly in the white matter where the metabolite alterations were also the most pronounced. Compared to the controls values, the white matter NAA (marker of neuronal metabolism) was 6% lower and mI (glia cell marker) 20% higher. Hyperglycemia is therefore a potent risk factor for diabetic brain disease and the metabolic brain alterations may appear even before any peripheral microvascular complications are detectable. During acute hyperglycemia (Study III), the increase in cerebral glucose content in the patients with type 1 diabetes was, dependent on brain region, between 1.1 and 2.0 mmol/l. An every-day hyperglycemic episode in a diabetic patient may therefore as much as double brain glucose concentration. While chronic hyperglycemia had led to accumulation of glucose in the white matter, acute hyperglycemia burdened predominantly the gray matter. Acute hyperglycemia also revealed that chronic fluctuation in blood glucose may be associated with alterations in glucose uptake or in metabolism in the thalamus. The cerebellar white matter appeared very differently from the cerebral (Study IV). In the non-diabetic men it contained twice as much glucose as the cerebrum. Diabetes had altered neither its glucose content nor the brain metabolites. The cerebellum seems therefore more resistant to the effects of hyperglycemia than is the cerebrum.