666 resultados para Disappeared


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The loss and recovery of intertidal seagrass meadows were assessed following the flood related catastrophic loss of seagrass meadows in February 1999 in the Sandy Strait, Queensland. Region wide recovery rates of intertidal meadows following the catastrophic disturbance were assessed by mapping seagrass abundance in the northern Great Sandy Strait region prior to and on 3 occasions after widespread loss of seagrass. Meadow-scale assessments of seagrass loss and recovery focussed on two existing Zostera capricorni monitoring meadows in the region. Mapping surveys showed that approximately 90% of intertidal seagrasses in the northern Great Sandy Strait disappeared after the February 1999 flooding of the Mary River. Full recovery of all seagrass meadows took 3 years. At the two study sites (Urangan and Wanggoolba Creek) the onset of Z. capricorni germination following the loss of seagrass occurred 14 months post-flood at Wanggoolba Creek, and at Urangan it took 20 months for germination to occur. By February 2001 (24 months post-flood) seagrass abundance at Wanggoolba Creek sites was comparable to pre-flood abundance levels and full recovery at Urangan sites was complete in August 2001 (31 months post-flood). Reduced water quality characterised by 2–3 fold increases in turbidity and nutrient concentrations during the 6 months following the flood was followed by a 95% loss of seagrass meadows in the region. Reductions in available light due to increased flood associated turbidity in February 1999 were the likely cause of seagrass loss in the Great Sandy Strait region, southern Queensland. Although seasonal cues influence the germination of Z. capricorni, the temporal variation in the onset of seed germination between sites suggests that germination following seagrass loss may be dependent on other factors (eg. physical and chemical characteristics of sediments and water). Elevated dissolved nitrogen concentrations during 1999 at Wanggoolba Creek suggest that this site received higher loads of sediments and nutrients from flood waters than Urangan. The germination of seeds at Wanggoolba Creek one year prior to Urangan coincides with relatively low suspended sediment concentrations in Wanggoolba Creek waters. The absence of organic rich sediments at Urangan for many months following their removal during the 1999 flood may also have inhibited seed germination. Data from population cohort analyses and population growth rates showed that rhizome weight and rhizome elongation rates increased over time, consistent with rapid growth during increases in temperature and light availability from May to October

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Ethiopia is believed to be the centre of origin and domestication for sorghum, where sorghum remains one of the main staple crops. Loss of biodiversity is occurring at an alarming rate in Ethiopia and crops, including sorghum, have long been recognized as vulnerable to genetic erosion. A major collection of sorghum germplasm was made in 1973 by Gebrekidan and Ejeta from north-eastern Ethiopia. A new collection of landraces was made in 2003, and these were field evaluated at Sirinka in 2004 along with representative samples from the 1973 collection. Farmer surveys and soil and climate surveys were also performed. Preliminary analysis demonstrated that some important landraces have disappeared either locally or regionally in the past 30 years and many other landraces have become marginalized. Landraces which are less preferred in terms of agronomic value and end use, and introductions, have become increasingly important. Late maturing landraces were found to be particularly vulnerable, with a number disappearing altogether. Farmers have become more risk averse, and factors such as declining soil fertility, more frequent drought and unreliable rainfall, and increased pest infestation have contributed to a change in farmer landrace selection. Data are presented on the variability and unique characters of some of the Ethiopian landraces, and implications for conservation are discussed.

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Remediation of Reading Difficulties in Grade 1. Three Pedagogical Interventions Keywords: initial teaching, learning to read, reading difficulties, intervention, dyslexia, remediation of dyslexia, home reading, computerized training In this study three different reading interventions were tested for first-graders at risk of reading difficulties at school commencement. The intervention groups were compared together and with a control group receiving special education provided by the school. First intervention was a new approach called syllable rhythmics in which syllabic rhythm, phonological knowledge and letter-phoneme correspondence are emphasized. Syllable rhythmics is based on multi-sensory training elements aimed at finding the most functional modality for every child. The second intervention was computerized training of letter-sound correspondence with the Ekapeli learning game. The third intervention was home-based shared book reading, where every family was given a story book, and dialogic reading style reading and writing exercises were prepared for each chapter of the book. The participants were 80 first-graders in 19 classes in nine schools. The children were matched in four groups according to pre-test results: three intervention and one control. The interventions took ten weeks starting from September in grade 1. The first post-test including several measures of reading abilities was administered in December. The first delayed post-test was administered in March, the second in September in grade 2, and the third, “ALLU” test (reading test for primary school) was administered in March in grade 2. The intervention and control groups differed only slightly from each other in grade 1. However, girls progressed significantly more than boys in both word reading and reading comprehension in December and this difference remained in March. The children who had been cited as inattentive by their teachers also lagged behind the others in the post-tests in December and March. When participants were divided into two groups according to their initial letter knowledge at school entry, the weaker group (maximum 17 correctly named letters in pre-test) progressed more slowly in both word reading and reading comprehension in grade 1. Intervention group and gender had no interaction effect in grade 1. Instead, intervention group and attentiveness had an interaction effect on most test measures the inattentive students in the syllable rhythmic group doing worst and attentive students in the control group doing best in grade 1. The smallest difference between results of attentive and inattentive students was in the Ekapeli group. In grade 2 still only minor differences were found between the intervention groups and control group. The only significant difference was in non-word reading, with the syllable rhythmics group outperforming the other groups in the fall. The difference between girls’ and boys’ performances in both technical reading and text comprehension disappeared in grade 2. The difference between the inattentive and attentive students cold no longer be found in technical reading, and the difference became smaller in text comprehension as well. The difference between two groups divided according to their initial letter knowledge disappeared in technical reading but remained significant in text comprehension measures in the ALLU test in the spring of grade 2. In all, the children in the study did better in the ALLU test than expected according to ALLU test norms. Being the weakest readers in their classes in the pre-test, 52.3 % reached the normal reading ability level. In the norm group 72.3 % of all students attained normal reading ability. The results of this study indicate that different types of remediation programs can be effective, and that special education has been apparently useful. The results suggest careful consideration of first-graders’ initial reading abilities (especially letter knowledge) and possible failure of attention; remediation should be individually targeted while flexibly using different methods.

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Background: The incidence of sexually transmitted infections (STIs) in most EU states has gradually increased and the rate of newly diagnosed HIV cases has doubled since 1999. STIs differ in their clinical features, prognosis and transmission dynamics, though they do share a common factor in their mode of transmission −that is, human behaviour. The evolvement of STI epidemiology involves a joint action of biological, epidemiological and societal factors. Of the more immediate factors, besides timely diagnosis and appropriate treatment, STI incidence is influenced by population patterns of sexual risk behaviour, particularly the number of sexual partners and the frequency of unprotected intercourse. Assessment of sexual behaviour, its sociodemographic determinants and time-trends are important in understanding the distribution and dynamic of STI epidemiology. Additionally, in the light of the basic structural determinants, such as increased level of migration, changes in gender dynamics and impacts from globalization, with its increasing alignment of values and beliefs, can reveal future challenges related to STI epidemiology. STI case surveillance together with surveillance on sexual behaviour can guide the identification of preventive strategies, assess their effectiveness and predict emerging trends. The objective of this study was to provide base line data on sexual risk behaviour, self-reported STIs and their patterns by sociodemographic factors as well as associations of sexual risk behaviour with substance use among young men in Finland and Estonia. In Finland national population based data on adult men s sexual behaviour is limited. The findings are discussed in the context of STI epidemiology as well as their possible implications for public health policies and prevention strategies. Materials and Methods: Data from three different cross-sectional population-based surveys conducted in Finland and Estonia, during 1998 2005, were used. Sexual behaviour- and health-related questions were incorporated in two surveys in Finland; the Health 2000, a large scale general health survey, focussed on young adults, and the Military health behavioural survey on military conscripts participating in the mandatory military training. Through research collaboration with Estonia, similar questions to the Finnish surveys were introduced to the second Estonian HIV/AIDS survey, which was targeted at young adults. All surveys applied mail-returned, anonymous, self-administered questionnaires with multiple choice formatted answers. Results: In Finland, differences in sexual behaviour between young men and women were minor. An age-stratified analysis revealed that the sex-related difference observed in the youngest age group (18 19 years) levelled off in the age group 20 24 and almost disappeared among those aged 25 29. Marital status was the most important sociodemographic correlate for sexual behaviour for both sexes, singles reporting higher numbers of lifetime-partners and condom use. This effect was stronger for women than for men. However, of those who had sex with casual partners, 15% were married or co-habiting, with no difference between male and female respondents. According to the Military health behavioural survey, young men s sexual risk behaviour in Finland did not markedly change over a period of time between 1998 and 2005. Approximately 30−40% of young men had had multiple sex partners (more than five) in their lifetime, over 20% reported having had multiple sex partners (at least three) over the past year and 50% did not use a condom in their last sexual intercourse. Some 10% of men reported accumulation of risk factors, i.e. having had both, multiple sex partners and not used a condom in their last intercourse, over the past year of the survey. When differences and similarities were viewed within Finland and Estonia, a clear sociodemographic patterning of sexual risk behaviour and self-reported STIs was found in Finland, but a somewhat less consistent trend in Estonia. Generally, both, alcohol and drug use were strong correlates for sexual risk behaviour and self-reported STIs in Finland and Estonia, having a greater effect on engagement with multiple sex partners rather than unprotected intercourse or self-reported STIs. In Finland alcohol use, relative to drug use, was a stronger predictor of sexual risk behaviour and self-reported STIs, while in Estonia drug use predicted sexual risk behaviour and self-reported STIs stronger than alcohol use. Conclusions: The study results point to the importance for prevention of sexual risk behaviour, particularly strategies that integrate sexual risk with alcohol and drug use risks. The results point to the need to focus further research on sexual behaviour and STIs among young people; on tracking trends among general population as well as applying in-depth research to identify and learn from vulnerable and high-risk population groups for STIs who are exposed to a combination of risk factors.

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The aims of this dissertation were 1) to investigate associations of weight status of adolescents with leisure activities, and computer and cell phone use, and 2) to investigate environmental and genetic influences on body mass index (BMI) during adolescence. Finnish twins born in 1983–1987 responded to postal questionnaires at the ages of 11-12 (5184 participants), 14 (4643 participants), and 17 years (4168 participants). Information was obtained on weight and height, leisure activities including television viewing, video viewing, computer games, listening to music, board games, musical instrument playing, reading, arts, crafts, socializing, clubs, sports, and outdoor activities, as well as computer and cell phone use. Activity patterns were studied using latent class analysis. The relationship between leisure activities and weight status was investigated using logistic and linear regression. Genetic and environmental effects on BMI were studied using twin modeling. Of individual leisure activities, sports were associated with decreased overweight risk among boys in both cross-sectional and longitudinal analyses, but among girls only cross-sectionally. Many sedentary leisure activities, such as video viewing (boys/girls), arts (boys), listening to music (boys), crafts (girls), and board games (girls), had positive associations with being overweight. Computer use was associated with a higher prevalence of overweight in cross-sectional analyses. However, musical instrument playing, commonly considered as a sedentary activity, was associated with a decreased overweight risk among boys. Four patterns of leisure activities were found: ‘Active and sociable’, ‘Active but less sociable’, ‘Passive but sociable’, and ‘Passive and solitary’. The prevalence of overweight was generally highest among the ‘Passive and solitary’ adolescents. Overall, leisure activity patterns did not predict overweight risk later in adolescence. An exception were 14-year-old ‘Passive and solitary’ girls who had the greatest risk of becoming overweight by 17 years of age. Heritability of BMI was high (0.58-0.83). Common environmental factors shared by family-members affected the BMI at 11-12 and 14 years but their effect had disappeared by 17 years of age. Additive genetic factors explained 90-96% of the BMI stability across adolescence. Genetic correlations across adolescence were high, which suggests similar genetic effects on BMI throughout adolescence, while unique environmental effects on BMI appeared to vary. These findings suggest that family-based interventions hold promise for obesity prevention into early and middle adolescence, but that later in adolescence obesity prevention should focus on individuals. A useful target could be adolescents' leisure time, and our findings highlight the importance of versatility in leisure activities.

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An investigation is presented of the daily variation of the maximum cloud zone (MCZ) and the 7W mb trough in the Northern Hemisphere over the Indian longitudes 70–90°E during April–October for 1973–77. It is found that during June–September there are two favorable locations for a MCZ over these longitudes–on a majority of days the MCZ is present in the monsoon zone north of 15°N, and often a secondary MCZ occurs in the equatorial region (0–10°N). The monsoon MCZ gets established by northward movement of the MCZ occurring over the equatorial Indian ocean in April and May. The secondary MCZ appears intermittently, and is characterized by long spells of persistence only when the monsoon MCZ is absent. In each of the seasons studied, the MCZ temporarily disappeared from the mean summer monsoon location (15–28°N) about four weeks after it was established near the beginning of July. It is reestablished by the northward movement of the secondary MCZ, which becomes active during the absence of the monsoon MCZ, in a manner strikingly similar to that observed in the spring to summer transition. A break in monsoon conditions prevails just prior to the temporary disappearance of the monsoon MCZ. Thus we conclude that the monsoon MCZ cannot survive for longer than a month without reestablishment by the secondary MCZ. Possible underlying mechanisms are also discussed.

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Europe was declared malaria free in 1975. The disappearance of malaria has traditionally been attributed to numerous deliberate actions like vector control, the screening of houses, more efficient medication etc. Malaria, however, disappeared from many countries like Finland before any counter measures had even started. The aim of this thesis is to study the population ecology of P. vivax and its interaction with the human host and the vector. By finding the factors that attributed to the extinction of vivax malaria it might be possible to improve the modern strategy against P. vivax. The parasite was studied with data from Finland, which provides the longest time series (1749-2008) of malaria statistics in the world. The malaria vectors, Anopheles messeae and A. beklemishevi are still common species in the country. The eradication of vivax malaria is difficult because the parasite has a dormant stage that can cause a relapse long after a primary infection. It was now shown that P. vivax is able to detect the presence of a potential vector. A dormant stage is triggered even from a bite of an uninfected Anopheles mosquito. This optimizes the chances for the Plasmodium to reach a mosquito vector for sexual reproduction. The longevity of the dormant stage could be shown to be at least nine years. The parasite spends several years in its human host and the behaviour of the human carrier had a profound impact on the decline of the disease in Finland. Malaria spring epidemics could be explained by a previous warm summer. Neither annual nor summer mean temperature had any impact on the long term malaria trend. Malaria disappeared slowly from Finland without mosquito control. The sociological change from extended families to nuclear families led to decreased household size. The decreased household size correlated strongly with the decline of malaria. That led to an increased isolation of the subpopulations of P. vivax. Their habitat consisted of the bedrooms in which human carriers slept together with the overwintering vectors. The isolation of the parasite ultimately led to the extinction of vivax malaria. Metapopulation models adapted to local conditions should therefore be implemented as a tool for settlement planning and socio-economic development and become an integrated part of the fight against malaria.

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The spot or strip application of poisoned protein bait is a lure-and-kill technique used for the management of fruit flies. Knowledge of where flies occur in the crop environment is an important part of maximizing the efficacy of this tool. Bactrocera tryoni is a polyphagous pest of horticulture for which very little is known about its distribution within crops. With particular reference to edge effects, we monitored the abundance of B. tryoni in two crops of different architecture; strawberry and apple. In strawberries, we found more flies on the crop edge early in the fruiting season, which lessened gradually and eventually disappeared as the season progressed. In apple orchards, no such edge effect was observed and flies were found equally throughout the orchard. We postulated these differences may be due to differences in crop height (high vs. short) and/or crop canopy architecture (opened and branched in apple, dense and closed in strawberry). In a field cage trial, we tested these predictions using artificial plants of different height and canopy condition. Height and canopy structure type had no significant effects on fly oviposition and protein feeding, but the ‘apple’ type canopy significantly influenced resting. We thus postulate that there was an edge effect in strawberry because the crop was not providing resting sites and flies were doing so in vegetation around the field margins. The finding that B. tryoni shows different resting site preferences based on plant architecture offers the potential for strategic manipulation of the fly through specific border or inter-row plantings.

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. The changes in the net amounts of retinol, retinyl esters and retinal in both the developing chick embryo and the newly hatched chick were investigated. The embryo requires about 68nmol of the vitamin for its growth, whereas the baby chick requires about 108nmol during the first 7 days after hatching. 2. Retinal was present in the egg in fairly high concentrations at the beginning of the incubation but it virtually disappeared from the extra-embryonic tissue after day 17 of incubation. It was not found in the liver of the embryo or of the newly hatched chick up until day 7.

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The records of the North American Jewish Students Appeal (NAJSA or APPEAL) contains documents on two levels of concern: those documents dealing with the NAJSA as a student-run organization promoting Jewish identity among college-aged youth; and those documents dealing with the APPEAL as a fundraising organization for several well-known student constituent organizations. The Constituents were: the Jewish Student Press Service, Lights in Action, the North American Jewish Students Network, the Progressive Zionist Caucus, Response: A Contemporary Jewish Review, Yavneh Religious Students Organization, and Yugntruf Youth for Yiddish. Documents include correspondence, financial records, minutes, press releases, information on grants awarded to student organizations for programming and publishing, student journals, and newspapers, photographs, and ephemera.

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The spot or strip application of poisoned protein bait is a lure-and-kill technique used for the management of fruit flies. Knowledge of where flies occur in the crop environment is an important part of maximizing the efficacy of this tool. Bactrocera tryoni is a polyphagous pest of horticulture for which very little is known about its distribution within crops. With particular reference to edge effects, we monitored the abundance of B. tryoni in two crops of different architecture; strawberry and apple. In strawberries, we found more flies on the crop edge early in the fruiting season, which lessened gradually and eventually disappeared as the season progressed. In apple orchards, no such edge effect was observed and flies were found equally throughout the orchard. We postulated these differences may be due to differences in crop height (high vs. short) and/or crop canopy architecture (opened and branched in apple, dense and closed in strawberry). In a field cage trial, we tested these predictions using artificial plants of different height and canopy condition. Height and canopy structure type had no significant effects on fly oviposition and protein feeding, but the 'apple' type canopy significantly influenced resting. We thus postulate that there was an edge effect in strawberry because the crop was not providing resting sites and flies were doing so in vegetation around the field margins. The finding that B. tryoni shows different resting site preferences based on plant architecture offers the potential for strategic manipulation of the fly through specific border or inter-row plantings. © 2013 Blackwell Verlag GmbH.

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1. The biopotencies relative to beta-carotene of several apocarotenoids, such as 8'-, 10'- and 12'-apo-beta-carotenal and methyl 8'-apo-beta-carotenoate, were investigated in rats, on a molar basis, by both curative-growth assay and liver-storage tests. 2. In the curative-growth assays, on a molar basis the biopotencies of 8'-, 10'- and 12'-apo-beta-carotenal and methyl 8'-apo-beta-carotenoate were 72, 78, 72 and 53% respectively, whereas on a weight basis the corresponding values were 93, 111, 111 and 63%, with respect to beta-carotene taken as 100%. In terms of yield of vitamin A, these values were much lower in the liver-storage tests. 3. When 8'-apo-beta-carotenal was fed, the unchanged aldehyde together with small amounts of the corresponding alcohol and larger proportions of the acid rapidly appeared in the tissues of both rats and chickens. The 8'-apocarotenol, 8'-apocarotenoic acid and its methyl ester were absorbed unchanged. The free acid disappeared most rapidly from the tissues, but its methyl ester persisted in the tissues longest. 4. On the basis of these observations it is suggested that most of an apocarotenal is oxidized to the corresponding acid, which, in turn, is mostly degraded to retinoic acid, with small proportions of it being attacked by the dioxygenase system giving retinal.

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The aim of the studies reported in this thesis was to examine the feeding interactions between calanoid copepods and toxic algae in the Baltic Sea. The central questions in this research concerned the feeding, survival and egg production of copepods exposed to toxic algae. Furthermore, the importance of copepods as vectors in toxin transfer was examined. The haptophyte Prymnesium parvum, which produces extracellular toxins, was the only studied species that directly harmed copepods. Beside this, it had allelopathic effects (cell lysis) on non-toxic Rhodomonas salina. Copepods that were exposed to P. parvum filtrates died or became severely impaired, although filtrates were not haemolytic (indicative of toxicity in this study). Monospecific Prymnesium cell suspensions, in turn, were haemolytic and copepods in these treatments became inactive, although no clear effect on mortality was detected. These results suggest that haemolytic activity may not be a good proxy of the harmful effects of P. parvum. In addition, P. parvum deterred feeding, and low egestion and suppressed egg production were consequently observed in monospecific suspensions of Prymnesium. Similarly, ingestion and faecal pellet production rates were suppressed in high concentration P. parvum filtrates and in mixtures of P. parvum and R. salina. These results indicate that the allelopathic effects of P. parvum on other algal species together with lowered viability as well as suppressed production of copepods may contribute to bloom formation and persistence. Furthermore, the availability of food for planktivorous animals may be affected due to reduced copepod productivity. Nodularin produced by Nodularia spumigena was transferred to Eurytemora affinis via grazing on filaments of small N. spumigena and by direct uptake from the dissolved pool. Copepods also acquired nodularin in fractions where N. spumigena filaments were absent. Thus, the importance of microbial food webs in nodularin transfer should be considered. Copepods were able to remove particulate nodularin from the system, but at the same time a large proportion of the nodularin disappeared. This indicates that copepods may possess effective mechanisms to remove toxins from their tissues. The importance of microorganisms, such as bacteria, in the degradation of cyanobacterial toxins could also be substantial. Our results were the first reports of the accumulation of diarrhetic shellfish toxins (DSTs) produced by Dinophysis spp. in copepods. The PTX2 content in copepods after feeding experiments corresponded to the ingestion of <100 Dinophysis spp. cells. However, no DSTs were recorded from field-collected copepods. Dinophysis spp. was not selected by the copepods and consumption remained low. It seems thus likely that copepods are an unimportant link in the transfer of DSTs in the northern Baltic Sea.

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Juvenile neuronal ceroid lipofuscinosis (JNCL) is one of the most common neurodegenerative diseases in childhood. Its clinical onset, with visual failure as the first sign, is between the ages of 4 to 8 years. During the disease progress, epilepsy, motor symptoms, cognitive decline, and psychiatric symptoms become apparent. It leads to premature death between ages 15 and 30. Treatment consists of symptomatic drug administration and various forms of rehabilitation, but to date, no curative treatment exists. To gain a more comprehensive picture of psychiatric problems, symptoms were evaluated by the Child Behavior Checklist, the Teacher Report Form, and the Children s Depression Inventory. The JNCL patients had a great number of severe psychiatric symptoms, with wide inter-individual variability. The most common symptoms were social, thought, attention, and sleep problems, somatic complaints, and aggressive behaviour. Patients with psychotropic treatment had more problems than did those without psychotropic treatment, and female patients had more problems than did males. Between 10 and 20% of the patients reported depressive symptoms. In a 5-year follow-up, [123I]β-CIT SPECT and MRI revealed a tendency of decreasing serotonin transporter (SERT) availability and progressive brain atrophy. The correlation between changes in midbrain SERT and total brain volume was positive; no correlation appeared between SERT or brain atrophy and depressive symptoms. Thus, it seems likely that the low SERT availability is associated with progressive brain atrophy; it may also predispose towards depression, however. An open survey of psychotropic drugs and their efficacy was performed on JNCL patients in Finland. The most commonly used psychotropic drugs were the antidepressant citalopram and the antipsychotic risperidone. Their efficacy was good or satisfactory in the majority of cases and they seemed well tolerated. Quetiapine had a marked effect on one patient with a history of severe psychotic symptoms. Glutamate decarboxylase 65 autoantibodies (GAD65ab), found in JNCL patients, indicate that an immunomediated reaction against GAD or GABAergic neurons may play a part in the underlying pathogenetic mechanism. GAD65ab s also appeared in the serum of all eight JNCL patients included and intermittent corticosteroid therapy was initiated in all cases. After one year, the GAD65ab s had disappeared in the two oldest patients, who experienced an improvement in motor symptoms and alertness associated with their prednisolone therapy. Two younger patients experienced a significant IQ increase, but no change in GADab s. A randomized study with longer follow-up time is needed, however, to clarify the effect of prednisolone on disease progression.

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The prevalence of variegate porphyria (VP) (2.1:100 000, in 2006 n=108) was higher in Finland than elsewhere in European countries due to a founder effect (R152C). The incidence of VP was estimated at 0.2:1 000 000 based on the number of new symptomatic patients yearly. The prevalence of porphyria cutanea tarda (PCT) was 1.2:100 000 (in 2006 n=63), which is only one fourth of the numbers reported from other European countries. The estimated incidence of PCT was 0.5:1 000 000. Based on measurements of the uroporphyrinogen decarboxylase activity in erythrocytes, the proportion of familial PCT was 49% of the cases. The prevalence of erythropoietic protoporphyria (EPP) was at 0.8:100 000 (in 2006 n=39) including asymptomatic carriers of a mutation in the ferrochelatase (FECH) gene. The incidence of EPP was estimated at 0.1:1 000 000. After 1980 the penetrance was 37% among patients with VP. Of the mutation carriers (n=57) 30% manifested with skin symptoms. Frequency of skin symptom as only clinical sign was stable before or after 1980 (22% vs. 21%), but acute attacks became infrequent (29% vs. 7%). Of the symptomatic patients 30% had both acute attacks and skin symptoms and 80% had skin symptoms. Fragility (95%) and blistering (46%) of the skin in the backs of the hands were the most common skin symptoms. Transient correction of porphyrin metabolism using eight haem arginate infusions within five weeks had no effect on the skin symptoms in three of four patients with VP. In one case skin symptoms disappeared transiently. One patient with homozygous VP had severe photosensitivity since birth. Sensory polyneuropathy, glaucoma and renal failure developed during the 25-year follow-up without the presence of acute attacks. The I12T mutation was detected in both of his alleles in the protoporphyrinogen oxidase gene. Lack of skin symptoms and infrequency of acute attacks (1/9) in the patients with I12T mutation at the heterozygous stage indicate a mild phenotype (the penetrance 11%). Four mutations (751delGAGAA, 1122delT, C286T, C343T) in the FECH gene were characterised in four of 15 families with EPP. Burning pain (96%) and swelling (92%) of the sun-exposed skin were the major skin symptoms. Hepatopathy appeared in one of 25 symptomatic patients (4%). Clinical manifestations and associated factors of PCT were similar in the sporadic and familial types of PCT. The majority of the patients with PCT had one to three precipitating factors: alcohol intake (78%), mutations in hemochromatosis associated gene (50%), use of oestrogen (25% of women) and hepatitis B or C infections (25 %). Fatty liver disease (67%) and siderosis (67%) were commonly found in their liver biopsies. The major histopathological change of the sun-exposed skin in the patients with VP (n=20), EPP (n=8) and PCT (n=5) was thickening of the vessel walls of the upper dermis suggesting that the vessel wall is the primary site of the phototoxic reaction in each type of porphyria. The fine structure of the vessel walls was similar in VP, EPP and PCT consisting of the multilayered basement membrane and excess of finely granular substance between the layers which were surrounded by the band of homogenous material. EPP was characterised by amorphous perivascular deposits extending also to the extravascular space. In direct immunofluorescence study homogenous IgG deposits in the vessel walls of the upper dermis of the sun-exposed skin were demonstrated in each type of porphyria. In EPP the excess material around vessel walls consisted of other proteins such as serum amyloid protein, and kappa and lambda light chains in addition to the basement membrane constituents such as collagen IV and laminin. These results suggest that the alterations of the vessel walls are a consequence of the repeated damage and the repairing process in the vessel wall. The microscopic alterations could be demonstrated even in the normal looking but sun-exposed skin of the patients with EPP during the symptom-free phase suggesting that vascular change can be chronic. The stability of vascular changes in the patients with PCT after treatment indicates that circulating porphyrins are not important for the maintenance of the changes.