Defining Adequate Vitamin D Intake : Cross-sectional and Intervention Studies

D-vitamiini ylläpitää normaalia luun kasvua ja uudistumista koko elämän ajan. Suomessa, kuten monissa muissakin länsimaissa, väestön D-vitamiinitilanne on riittämätön – talvisin osalla jopa puutteellinen. Tässä väitöskirjassa on tutkittu, lisääkö D-vitamiini luumassan kertymistä kasvuiässä, ja ylläpitäkö D-vitamiini luuston tasapainoista aineenvaihduntaa aikuisiällä. Nämä vaikutukset saattavat ehkäisi osteoporoosin kehittymistä eri ikäkausina. Väitöskirjatyössä tutkittiin erisuuruisten D-vitamiinilisäysten vaikutuksia kolmessa eri ikäryhmässä, jotka olivat 11-12 -vuotiaat tytöt (N=228), 21-49 -vuotiaat miehet (N=54) ja 65-85 -vuotiaat naiset (N=52). Tutkittavat satunnaistettiin ryhmiin, jotka nauttivat joko lumevalmistetta tai 5-20 µg D3-vitamiinia vitamiinilisänä. Tutkimukset olivat kaksoissokkoutettuja. Tutkimuksen aikana tutkittavilta otettiin paastoveri- ja virtsanäytteitä. Lisäksi he täyttivät tutkimuslomakkeen taustatietojen kartoittamiseksi sekä frekvenssikyselylomakkeen kalsiumin ja D-vitamiinin saannin selvittämiseksi. Tyttöjen luunmineraalitiheys (BMD) mitattiin DXA–laitteella ja miesten volumetrinen luuntiheys pQCT-menetelmällä. Näytteistä määritettiin mm. seerumin 25-hydroksi-D-vitamiinin (=S-25-OHD), lisäkilpirauhashormonin (=S-PTH) ja luun aineenvaihduntaa kuvaavien merkkiaineiden pitoisuuksia. Murrosikäisten tyttöjen poikkileikkaustutkimuksessa S-25-OHD- ja luun muodostusmerkkiaineen pitoisuudet vaihtelivat kuukausien välillä; suurimmat pitoisuudet mitattiin syyskuussa ja pienimmät maaliskuussa, mikä kuvastaa vuodenaikaisvaihtelua. Vastaava vaihtelu havaittiin lannerangan ja reisiluun BMD:ssä. D-vitamiinilisäyksellä oli myönteinen vaikutus tyttöjen luumassan lisääntymiseen. Suurin D-vitamiinilisä (10 µg/vrk) lisäsi luumassaa 17.2% enemmän reisiluussa ja 12.5% enemmän lannerangassa verrattuna lumevalmistetta nauttivien tyttöjen vastaaviin tuloksiin, mutta tulos riippui hoitomyöntyvyydestä. D-vitamiinin vaikutus luustoon välittyi vähentyneen luun hajotuksen kautta. Tutkimustuloksiin perustuen riittävä D-vitamiinin saanti murrosikäisille tytöille on 15 µg/vrk. D-vitamiinilisän vaikutus 65-85 -vuotiaiden naisten S-25-OHD-pitoisuuteen vakioitui kuudessa viikossa annoksen ollessa 5-20 µg/vrk. Näillä D-vitamiiniannoksilla ei saavutettu tavoiteltavaa S-25-OHD-pitoisuutta, joka on 80 nmol/l. Arvioimme, että 60 nmol/l -pitoisuuden, jota esiintyy kesäisin tämän ikäryhmän suomalaisilla, tämän ikäryhmän naiset saavuttaisivat 24 µg:n päivittäisellä D-vitamiinin saannilla. Terveillä miehillä havaittiin vuodenaikaisvaihtelu S-25-OHD- ja S-PTH-pitoisuudessa sekä luun hajotusta kuvaavassa merkkiainepitoisuudessa. Toisaalta vaihtelua ei havaittu radiuksen volumetrisessä luuntiheydessä eikä luun muodostusmerkkiaineen pitoisuudessa. Vuodenaikaisvaihtelu estettiin 17 µg:n päivittäisellä D-vitamiinin saannilla, mutta tämän ei havaittu vaikuttavan radiuksen luuntiheyteen kuusi kuukautta kestävän tutkimuksen aikana. Yhteenvetona todetaan, että D-vitamiinin saanti on edelleenkin riittämätöntä tutkimusten kohderyhmillä. Tämä näkyy S-25-OHD- ja PTH-pitoisuuden sekä luunaineenvaihduntaa kuvaavien merkkiaineiden vuodenaikaisvaihteluna, mikä on haitallista luuston hyvinvoinnille. D-vitamiinin saantia tulisi lisätä, jotta vähintäänkin riittävä D-vitamiinitilanne (S-25-OHD>50 nmol/l) tai mahdollisesti jopa tavoiteltava D-vitaminitilanne (S-25-OHD≥80 nmol/l) saavutettaisiin. Jotta D-vitamiinin saannin lisääminen olisi kaikissa ikäryhmissä mahdollista, on suunniteltava nykyistä enemmän D-vitamiinilla täydennettyjä elintarvikkeita.

Population structure and evolution in the ant Plagiolepis pygmaea and its two social parasites Plagiolepis xene and Plagiolepis grassei

Social behaviour affects dispersal of animals and is an important modifier of genetic population structures. The female sex is often philopatric, which maintains coancestry within the breeding groups and promotes cooperative behaviours. This enables also inclusive fitness returns from altruism and explains why some individuals sacrifice personal reproduction for the good of others in social insects such as ants. However, reduced dispersal and population substructuring at the level of colonies may also entail inbreeding, loss of genetic diversity, and vulnerability. In addition, the most vulnerable ants are species that are evolved to parasitize colonies of other ants, and which compromise between abilities to disperse and the efficiency to parasitize the host. On the other hand, certain social organisations of ant colonies may facilitate a species to disperse outside its natural range and become a pest. Altogether, knowledge on genetic structuring of ant populations, as well as the evolution of their life histories can contribute to conservation biology and population management. The aim of this thesis was to investigate population structures and phylogenetic evolution of the ant Plagiolepis pygmaea and its two obligatory, workerless social parasites (inquilines) P. xene and P. grassei with genetic markers and DNA sequence data. The results support the general assumption that populations of inquiline parasites are highly fragmented and genetically vulnerable. Comparison of the two parasites suggests that differences in their relative abundance may follow from their interaction with the host, i.e. how well the species is adapted to reproduce in the host colonies. The results also indicate that the most recent free living ancestor to these two parasite species is their common host. This is considered to provide evidence for the controversial issue of sympatric speciation. Further, given that the level of adaptations to parasitic life history depends on the evolutionary time since the free-living ancestor, the results establish a link between species rarity and its evolutionary age. The populations of the host species P. pygmaea displayed significantly reduced dispersal both among the females (queens) and males, and high levels of inbreeding which may enhance worker altruism. In addition, the queens were found to mate with multiple males. Given the high relatedness between the queens and their mates, this occurs probably for non-genetic reasons, e.g. without benefits associated in genetically more diverse offspring. The results hence caution that the contribution of non-genetic factors to the prevailing mating patterns and genetic population structures should not be underestimated.

Community Pharmacies and the Needs of Mobile EU Citizens - A study on Finns living in Spain

Migration within the European Union (EU) has increased since the Union was established. Community pharmacies provide open access to health care services and can be the first, most frequently used or even the only contact with a nation s health care system among mobile community residents. In some of the mass-migration areas in Southern Europe, most of the customers may represent mobile citizens of foreign background. This has not always been taken into consideration in the development of community pharmacy services. Mobile patients have been on the EU's health policy agenda, but they have seldom been mentioned in the context of community pharmacies. In most of the EU member states, governments control the specific legislation concerning community pharmacies and there is no harmonised pharmaceutical policy or consistent minimal standards for community pharmacy services in the EU. The aim of this study was to understand medication use, the role of community pharmacies and the symptom mitigation process of mobile community residents. Finns living in Spain were used as an example to examine how community pharmacies in a EU member state meet the needs of mobile community residents. The data were collected by a survey in 2002 (response rate 53%, n= 533) and by five focus group discussions in 2006 (n=30). A large number (70%) of the respondents had moved to Spain for health reasons and suffered from chronic morbidity. Community pharmacies had an important role in the healthcare of mobile community residents and the respondents were mostly satisfied with these services. However, several medication safety risks related to community pharmacy practices were identified: 1) Availability of prescription medicines without prescription (e.g., antibiotics, sleeping pills, Viagra®, asthma medications, cardiovascular medicines, psoriasis medicines and analgesics); 2) Irrational use of medicines (e.g., 41% of antibiotic users had bought their antibiotics without a prescription, and the most common reasons for antibiotic self-medication were symptomatic common colds and sore throats); 3) Language barriers between patients and pharmacy professionals; 4) Lack of medication counselling; 5) Unqualified pharmacy personnel providing pharmacotherapy. A fifth of the respondents reported experiencing problems during pharmacy visits in Spain, and the lack of a common language was the source of most of these problems. The findings of this study indicate that regulations and their enforcement can play a crucial role in actually assuring the rational and safe use of medicines. These results can be used in the development of pharmaceutical and healthcare policies in the EU. It is important to define consistent minimum standards for community pharmacy services in the EU. Then, the increasing number of mobile community residents could access safe and high quality health care services, including community pharmacy services, in every member state within the EU.

Kadonneet pojat : Monitapaustutkimus ESY-poikien kompleksisesta koulu-urasta ja elämänkulusta

Lost boys. A multiple case study of the complex school career and life-course of male students who have attended special classes for the emotionally and behaviourally maladjusted The purpose of this thesis is to describe the school career and the life-course of eight former special-class students from the comprehensive school to their further education and into adulthood. The members of the target group have been students of special classes for pupils with emotional and behavioural difficulties in southern Finland. The interviews were made 1994-1997 at school and for follow-up interviews 2002-2003, when the participants were already adults. Six mothers were also interviewed. The qualitative data was gathered using individual interviews and Adult Attachment Interview. The aim was to explore the life-histories of subjects from early childhood to early adulthood. Information was gathered also from the documents concerning the students´ school attendance. Every single life-history is illustrated as a life-course graphic. The data has been analysed using different frames of reference and combining different theories. In addition to theories considering developmental risk factors and protective factors, the data is considered using theories of control over life, attribution, self-efficacy and identity and attitudes towards education. The experiential living mode of the students has been studied, as well. The results of this study show that the frames of references which are used complement each other. The target students clustered identically in spite of the frames of reference. As a result, the study has illustrated the same phenomenon from different points of view. The results of the study consist of three types of school careers: The winding career, the vicious circle career and the straight career. The three careers differ from each other in developmental risk and protective factors and post-school life-courses of the students. The type of childhood families and especially the fathers´ attention to the school education as well as the free time of their sons was important. Keywords: Pupils with emotional and behavioural difficulties, maladjustment to school, life-course, identity

Living arrangements and health

In line with major demographic changes in other Northern European and North American countries and Australia, being nonmarried is becoming increasingly common in Finland, and the proportion of cohabiters and of persons living alone has grown in recent decades. Official marital status no longer reflects an individual s living arrangement, as single, divorced and widowed persons may live alone, with a partner, with children, with parents, with siblings, or with unrelated persons. Thus, more than official marital status, living arrangements may be a stronger discriminator of one s social bonds and health. The general purpose of this study was to deepen our current understanding of the magnitude, trends, and determinants of ill health by living arrangements in the Finnish working-age population. Distinct measures of different dimensions of poor health, as well as an array of associated factors, provided a comprehensive picture of health differences by living arrangements and helped to assess the role of other factors in the interpretation of these differences . Mortality analyses were based on Finnish census records at the end of 1995 linked with cause-of-death registers for 1996 2000. The data included all persons aged 30 and over. Morbidity analyses were based on two comparable cross-sectional studies conducted twenty years apart (the Mini-Finland Survey in 1978 80 and the Health 2000 Survey in 2000 01). Both surveys were based on nationally representative samples of Finns aged 30 and over, and benefited from high participation rates. With the exception of mortality analyses, this study focused on health differences among the working-age population (mortality in age groups 30-64 and 65 and over, self-rated health and mental health in the age group 30-64, and unhealthy alcohol use in the age group 30-54). Compared with all nonmarried groups, married men and women exhibited the best health in terms of mortality, self-rated health, mental health and unhealthy alcohol use. Cohabiters did not differ from married persons in terms of self-rated health or mental health, but did exhibit excess unhealthy alcohol use and high mortality, particularly from alcohol-related causes. Compared with the married, persons living alone or with someone other than a partner exhibited elevated mortality as well as excess poor mental health and unhealthy alcohol use. By all measures of health, men and women living alone tended to be in the worst position. Over the past twenty years, SRH had improved least among single men and women and widowed women, and most among cohabiting women. The association between living arrangements and health has many possible explanations. The health-related selection theory suggests that healthy people are more likely to enter and maintain a marriage or a consensual union than those who are unhealthy (direct selection) or that a variety of health-damaging behavioural and social factors increase the likelihood of ill health and the probability of remaining without a partner or becoming separated from one s partner (indirect selection). According to the social causation theory, marriage or cohabitation has a health-promoting effect, whereas living alone or with others than a partner has a detrimental effect on health. In this study, the role of other factors that are mainly assumed to reflect selection, appeared to be rather modest. Social support, which reflects social causation, contributed only modestly to differences in unhealthy alcohol use by living arrangements, but had a larger effect on differences in poor mental health. Socioeconomic factors and health-related behaviour, which reflect both selection and causation, appeared to play a more important role in the excess poor health of cohabiters and of persons living alone or with someone other than a partner, than of married persons. Living arrangements were strongly connected to various dimensions of ill health. In particular, alcohol consumption appeared to be of great importance in the association between living arrangements and health. To the extent that the proportion of nonmarried persons continues to grow and their health does not improve at the same rate as that of married persons, the challenges that currently nonmarried persons pose to public health will likely increase.

Living on the edge : Population genetics of Finno-Ugric-speaking humans in North Eurasia

The major aim of this thesis was to examine the origins and distribution of uniparental and autosomal genetic variation among the Finno-Ugric-speaking human populations living in Boreal and Arctic regions of North Eurasia. In more detail, I aimed to disentangle the underlying molecular and population genetic factors which have produced the patterns of uniparental and autosomal genetic diversity in these populations. Among Finno-Ugrics the genetic amalgamation and clinal distribution of West and East Eurasian gene pools were observed within uniparental markers. This admixture indicates that North Eurasia was colonized through Central Asia/ South Siberia by human groups already carrying both West and East Eurasian lineages. The complex combination of founder effects, gene flow and genetic drift underlying the genetic diversity of the Finno-Ugric- speaking populations were emphasized by low haplotype diversity within and among uniparental and biparental markers. A high prevalence of lactase persistence allele among the North Eurasian Finno- Ugric agriculturalist populations was also shown indicating a local adaptation to subsistence change with lactose rich diet. Moreover, the haplotype background of lactase persistence allele among the Finno- Ugric-speakers strongly suggested that the lactase persistence T-13910 mutation was introduced independently more than once to the North Eurasian gene pool. A significant difference in genetic diversity, haplotype structure and LD distribution within the cytochrome P450 CYP2C and CYP2D regions revealed the unique gene pool of the Finno-Ugric Saami created mainly by population genetic processes compared to other Europeans and sub-Saharan Mandenka population. From all studied populations the Saami showed also significantly the highest allele frequency of a CYP2C19 gene mutation causing variable drug reactions. The diversity patterns observed within CYP2C and CYP2D regions emphasize the strong effect of demographic history shaping genetic diversity and LD especially among such small and constant size populations as the Finno-Ugric-speaking Saami. Moreover, the increased LD in Saami due to genetic drift and/or admixture was shown to offer an advantage for further attempts to identify alleles associated to common complex pharmacogenetic traits.

Serum uric acid and metabolic risk factors in three ethnic groups: Asian Indians and Creoles in Mauritius and Chinese in Qingdao, China

In humans with a loss of uricase the final oxidation product of purine catabolism is uric acid (UA). The prevalence of hyperuricemia has been increasing around the world accompanied by a rapid increase in obesity and diabetes. Since hyperuricemia was first described as being associated with hyperglycemia and hypertension by Kylin in 1923, there has been a growing interest in the association between elevated UA and other metabolic abnormalities of hyperglycemia, abdominal obesity, dyslipidemia, and hypertension. The direction of causality between hyperuricemia and metabolic disorders, however, is unceartain. The association of UA with metabolic abnormalities still needs to be delineated in population samples. Our overall aims were to study the prevalence of hyperuricemia and the metabolic factors clustering with hyperuricemia, to explore the dynamical changes in blood UA levels with the deterioration in glucose metabolism and to estimate the predictive capability of UA in the development of diabetes. Four population-based surveys for diabetes and other non-communicable diseases were conducted in 1987, 1992, and 1998 in Mauritius, and in 2001-2002 in Qingdao, China. The Qingdao study comprised 1 288 Chinese men and 2 344 women between 20-74, and the Mauritius study consisted of 3 784 Mauritian Indian and Mauritian Creole men and 4 442 women between 25-74. In Mauritius, re-exams were made in 1992 and/or 1998 for 1 941 men (1 409 Indians and 532 Creoles) and 2 318 non pregnant women (1 645 Indians and 673 Creoles), free of diabetes, cardiovascular diseases, and gout at baseline examinations in 1987 or 1992, using the same study protocol. The questionnaire was designed to collect demographic details, physical examinations and standard 75g oral glucose tolerance tests were performed in all cohorts. Fasting blood UA and lipid profiles were also determined. The age-standardized prevalence in Chinese living in Qingdao was 25.3% for hyperuricemia (defined as fasting serum UA > 420 μmol/l in men and > 360 μmol/l in women) and 0.36% for gout in adults between 20-74. Hyperuricemia was more prevalent in men than in women. One standard deviation increase in UA concentration was associated with the clustering of metabolic risk factors for both men and women in three ethnic groups. Waist circumference, body mass index, and serum triglycerides appeared to be independently associated with hyperuricemia in both sexes and in all ethnic groups except in Chinese women, in whom triglycerides, high-density lipoprotein cholesterol, and total cholesterol were associated with hyperuricemia. Serum UA increased with increasing fasting plasma glucose levels up to a value of 7.0 mmol/l, but significantly decreased thereafter in mainland Chinese. An inverse relationship occurred between 2-h plasma glucose and serum UA when 2-h plasma glucose higher than 8.0 mmol/l. In the prospective study in Mauritius, 337 (17.4%) men and 379 (16.4%) women developed diabetes during the follow-up. Elevated UA levels at baseline increased 1.14-fold in risk of incident diabetes in Indian men and 1.37-fold in Creole men, but no significant risk was observed in women. In conclusion, the prevalence of hyperuricemia was high in Chinese in Qingdao, blood UA was associated with the clustering of metabolic risk factors in Mauritian Indian, Mauritian Creole, and Chinese living in Qingdao, and a high baseline UA level independently predicted the development of diabetes in Mauritian men. The clinical use of UA as a marker of hyperglycemia and other metabolic disorders needs to be further studied. Keywords: Uric acid, Hyperuricemia, Risk factors, Type 2 Diabetes, Incidence, Mauritius, Chinese

Effects of living crown reduction on needle element status of Scots pine

A wide range of biotic and abiotic factors, operating over different time perspectives and intensities, cause defoliation and a rapid decrease in the crown size of trees. Scleroderris canker disease [Gremmeniella abietina (Lagerb.) Morelet] has caused widespread crown reduction and tree mortality in Scots pine (Pinus sylvestris L) in forests in Scandinavia during the last three decades. In the 1980's, attempts were made to show, on the basis of the higher foliar N and S concentrations of affected pines in the diseased area, that sulphur and nitrogen deposition predispose trees to G. abietina. Unfortunately, in many studies on defoliated trees, exceptionally high or low needle mineral nutrient concentrations are still often interpreted as one of the causes of tree injury and not, conversely, as the result. In this thesis, three different field experiments, with foliar analysis as the main study method, were conducted in order to asses the possible long-term effects of living crown reduction on the needle nutrient concentrations of Scots pine trees in southern Finland. The crown ratio and length of the living crown were used to estimate the amount of defoliation in the reduced canopies. The material for the partial studies was collected and a total of 968 foliar samples were analysed individually (15-17 elements/sample) on a total of 488 sample trees (140 diseased, 116 pruned and 232 control trees) during the years 1987-1996 in 13 Scots pine stands. All the three experiments of this thesis provided significant evidence that severe, disease-induced defoliation or artificial pruning of the living branches can induce long-lasting nutritional changes in the foliage of the recovering trees under the typical growing conditions for Scots pine. The foliar concentrations of all the 17 mineral nutrients/elements analysed were affected, to a varying degree, by artificial pruning during the following three years. Although Scots pine, as an evergreen conifer, is considered to have low induced chemical responses to defoliation, this study proved experimentally under natural forest conditions that severe artificial pruning or disease-induced defoliation of Scots pine trees may induce biologically significant changes in the concentrations of most of the important macro- and micronutrients, as well as of carbon, in refoliated needles. Concerning the studies in this thesis, I find the results significant in providing new information about the long-term effects of rapid living crown reduction on the foliar nutrient and element status of Scots pine trees. Key words: Foliar analysis, defoliation, needle loss, pruning, nutrients, Pinus sylvestris, Gremmeniella abietina

Biological Control of Oilseed Rape Pests with Entomopathogenic Nematodes

Biological control techniques attract increasing attention as one of the sustainable alternatives to pesticide use in integrated pest management programs. In order to develop sustainable pest management methods for arable crops based on entomopathogenic nematodes (EPN), their efficacy and persistence needed to be investigated, and an economically feasible delivery system had to be developed. In this study, first a survey of entomopathogens was conducted, and a system approach was tested, using the oilseed Brassica (OSB) growing system (OSB, spring wheat, and red clover) as a model. The system approach aimed at determining the potential of Steinernema feltiae (Filipjev) for the control of OSB pests, developing OSB rotation schemes that support EPN persistence, and investigating the impact of the selected biotic and abiotic factors on efficacy and persistence of EPN. This study employed abductive logic (which employs constant interplay between the theory and empirical observation), quantitative methods, and a case study on OSB. Laboratory and field experiments were carried out, and two types of pathogen surveys. A horizontal survey included OSB fields across Estonia, Germany, Poland, Sweden and the UK, while a vertical survey included sampling from two sets of differently managed experimental fields during three years. A new approach was introduced for measuring occurrence, where the prevalence and relative intensity of entomopathogens, biotic agents, and unidentified insect antagonists were determined. The effect of dose, timing, and the application method on S. feltiae in the control of pests in OSB, and the potential of a controlled release delivery system (CRS) were evaluated in the field. Studies on the impact of selected biotic and abiotc factors (Brassica plant, bait insects, developmental stages of Meligethes aeneus Fab., Isaria fumosorosea Wize (Ifr), and organic and synthetic fertilizers) on the efficacy of S. feltiae were conducted in the laboratory. Persistence of S. feltiae in the OSB growing system, and the effect of dose, timing, and the application method, was assessed in the field as part of the efficacy experiments. The impact of selected biotic and abiotic factors on S. feltiae persistence was assessed in laboratory experiments. The pathogen survey showed that the occurrence of entomopathogens is low in the OSB growing system, and that a management system causing less disturbance (ICM) to the soil increases the relative intensity of insect parasitic nematodes and other insect antagonists. A longer study period is required to show any possible impact of ICM on the relative intensity of entomopathogenic fungi, or on the prevalence of entomopathogens. Two different measures of the occurrence yielded different results: the relative intensity revealed the difference between the two different crop management methods, while prevalence did not. The highest efficacy of S. feltiae was achieved by using a low dose and targeting all stages of M. aeneus. When only the larval stage was targeted, the application method and dose had no significant effect. The CRS decreased the pest abundance significantly more than the surface application method. S. feltiae persisted in the OSB fields in Finland for several months, but did not survive the winter. The strain survived for 7 months when it was applied in autumn in Germany, but its populations declined rapidly after winter. The examined biotic and abiotic factors had variable impacts on S. feltiae efficacy and persistence. The two measures, prevalence and relative intensity of entomopathogens, gave valuable information for their use in biocontrol programs. The recommended biocontrol strategy for OSB growing in Finland is inundation and seasonal inoculation of EPN. The impact of some biotic and abiotic factors on S. feltiae efficacy and persistence is significant, and can be used to improve the efficacy of EPN. The CRS is a novel alternative for EPN application, and should also be considered for use on other crops. Keywords: Biological control, inundation, inoculation, conservation, formulation, slow release method, crop rotation, Entomopathogenic nematodes, Steinernema feltiae, oilseed rape pests, Meligethes aeneus, Phyllotreta spp., occurrence, prevalence, intensity, efficacy, persistence, field, Isaria fumosorosea, biotic factors, abiotic factors, interaction, impact, insect stages, integrated crop management, standard (conventional) crop management

Glycogen debranching enzyme activity in the muscles of meat producing animals

Muscle glycogen exists in two forms: low molecular weight pro-glycogen and high molecular weight macro-glycogen. The degradation of glycogen to glucose 1 phosphate and free glucose is catalysed by glycogen phosphorylase together with glycogen debranching enzyme (GDE). The process in which glycogen is broken down via anaerobic pathways to lactate, results in the acidification of the muscles and has a great influence on meat quality. Thus, the overall aim of this thesis was to characterise the post mortem action of GDE in muscles of meat production animals (pigs, cattle and chickens). Interest was focused on the differences in GDE activity between fast twitch glycolytic muscles and slow twitch oxidative muscles. The effects of pH, temperature, RN genotype (PRKAG3 gene), and of time post mortem on GDE activity were also investigated. This thesis showed that there are differences in GDE activity between animal species and between different muscles of an animal. It was shown that in pigs and cattle, higher GDE activity and phosphorylase activity exists in the fast twitch glycolytic muscles than in slow twitch oxidative muscles of the same animal. Thus, the high activity of these enzymes enables a faster rate of glycogenolysis in glycolytic M. longissimus dorsi compared to oxidative M. masseter. In chicken muscles, the GDE activity was low compared to pig or cattle muscles. Furthermore, the GDE activity in the glycolytic M. pectoralis superficialis was lower than in more oxidative M. quadriceps femoris despite the high phosphorylase activity in the former. The relative ratios between phosphorylase and GDE activity were higher in fast twitch glycolytic muscles than in slow twitch oxidative muscles of all studied animals. This suggests that the relatively low GDE activity compared to the phosphorylase activity in fast twitch glycolytic muscles may be a protection mechanism in living muscle against a very fast pH decrease. Chilling significantly decreased GDE activity and below 15 C porcine GDE was almost inactive. The effect of pH on GDE activity was only minor at the range normally found in post mortem muscles (pH 7.4 to 5.0). The GDE activity remained level for several hours after slaughter. During the first hours post mortem, GDE activity was similar in RN- carrier pigs and in wild type pigs. However, the GDE activity declined faster in M. longissimus dorsi from wild type pigs than in the RN carrier pigs, the difference between genotypes was significant after 24 h post mortem. Pro-glycogen and macro-glycogen contents were higher, pH decrease was faster and ultimate pH was lower in RN- carrier pigs than in wild type pigs. In the RN- carriers, the prolonged high GDE activity level may enable an extended pH decrease and lower ultimate pH in their muscles. In conclusion, GDE is not the main factor determining the rate or the extent of post mortem glycogenolysis, but under certain conditions, such as in very fast chilling, the inhibition of GDE activity in meat may reduce the rate of pH decrease and result in higher ultimate pH. The rate and extent of pH decrease affects several meat quality traits.

The kinetics and reactivity of several polyatomic free radicals in reactions with NO2, O2, Cl2, and HCl

In this thesis, the kinetics of several alkyl, halogenated alkyl, and alkenyl free radical reactions with NO2, O2, Cl2, and HCl reactants were studied over a wide temperature range in time resolved conditions. Laser photolysis photoionisation mass spectrometer coupled to a flow reactor was the experimental method employed and this thesis present the first measurements performed with the experimental system constructed. During this thesis a great amount of work was devoted to the designing, building, testing, and improving the experimental apparatus. Carbon-centred free radicals were generated by the pulsed 193 or 248 nm photolysis of suitable precursors along the tubular reactor. The kinetics was studied under pseudo-first-order conditions using either He or N2 buffer gas. The temperature and pressure ranges employed were between 190 and 500 K, and 0.5 45 torr, respectively. The possible role of heterogeneous wall reactions was investigated employing reactor tubes with different sizes, i.e. to significantly vary the surface to volume ratio. In this thesis, significant new contributions to the kinetics of carbon-centred free radical reactions with nitrogen dioxide were obtained. Altogether eight substituted alkyl (CH2Cl, CHCl2, CCl3, CH2I, CH2Br, CHBr2, CHBrCl, and CHBrCH3) and two alkenyl (C2H3, C3H3) free radical reactions with NO2 were investigated as a function of temperature. The bimolecular rate coefficients of all these reactions were observed to possess negative temperature dependencies, while pressure dependencies were not noticed for any of these reactions. Halogen substitution was observed to moderately reduce the reactivity of substituted alkyl radicals in the reaction with NO2, while the resonance stabilisation of the alkenyl radical lowers its reactivity with respect to NO2 only slightly. Two reactions relevant to atmospheric chemistry, CH2Br + O2 and CH2I + O2, were also investigated. It was noticed that while CH2Br + O2 reaction shows pronounced pressure dependence, characteristic of peroxy radical formation, no such dependence was observed for the CH2I + O2 reaction. Observed primary products of the CH2I + O2 reaction were the I-atom and the IO radical. Kinetics of CH3 + HCl, CD3 + HCl, CH3 + DCl, and CD3 + DCl reactions were also studied. While all these reactions possess positive activation energies, in contrast to the other systems investigated in this thesis, the CH3 + HCl and CD3 + HCl reactions show a non-linear temperature dependency on the Arrhenius plot. The reactivity of substituted methyl radicals toward NO2 was observed to increase with decreasing electron affinity of the radical. The same trend was observed for the reactions of substituted methyl radicals with Cl2. It is proposed that interactions of frontier orbitals are responsible to these observations and Frontier Orbital Theory could be used to explain the observed reactivity trends of these highly exothermic reactions having reactant-like transition states.

Measuring and tracking quality factors in Free and Open Source Software projects

Free and Open Source Software (FOSS) has gained increased interest in the computer software industry, but assessing its quality remains a challenge. FOSS development is frequently carried out by globally distributed development teams, and all stages of development are publicly visible. Several product and process-level quality factors can be measured using the public data. This thesis presents a theoretical background for software quality and metrics and their application in a FOSS environment. Information available from FOSS projects in three information spaces are presented, and a quality model suitable for use in a FOSS context is constructed. The model includes both process and product quality metrics, and takes into account the tools and working methods commonly used in FOSS projects. A subset of the constructed quality model is applied to three FOSS projects, highlighting both theoretical and practical concerns in implementing automatic metric collection and analysis. The experiment shows that useful quality information can be extracted from the vast amount of data available. In particular, projects vary in their growth rate, complexity, modularity and team structure.