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PubMed2002

Epidemiology of multiple sclerosis in the Canary Islands (Spain): a study on the island of La Palma.

OBJECTIVE: To determine the prevalence of multiple sclerosis (MS) on the Island of La Palma, Canary Islands, Spain. METHODS: A population-based transverse study was carried out on the Island of La Palma (population: 81,507), from 1995 to 1998. The 15 December 1998 was established as prevalence day. Sources of information were periodically obtained from case records from public primary care centres, private hospitals, private centres, magnetic resonance units and others. In accordance with the Poser criteria all cases of definite or probable MS were included. RESULTS: 34 cases of MS were found on prevalence day (9 male and 25 female): 32 cases were clinically definite and 2 were clinically probable MS. Crude prevalence was 42/100,000. Incidence during time of study was 2.25/100,000. CONCLUSIONS: The island of La Palma could be considered as an area of medium-high risk, the risk being higher than that expected because of the geographical latitude of the island. This study confirms the hypothesis of the high prevalence of MS in Spain. We have not found significant clinical differences in MS patients from those in other studies.

Adolescent↗

PubMed2000

Molecular analysis of hepatitis D virus infection in Miyako Island, a small Japanese island.

The present investigation attempted to determine the exact prevalence of hepatitis D virus (HDV) infection among inhabitants of Miyako Island (a remote island in the Okinawa Prefecture) and the molecular characteristics of the HDV genome that was isolated. Among the 4728 inhabitants, 375 (7.9%) were hepatitis B surface antigen (HBsAg) positive. Antibody to HDV (anti-HDV) was present in 32 (8. 5%) of these 375 subjects, and liver function tests were normal in most subjects. The presence of HDV RNA was analysed by nested polymerase chain reaction (PCR). Thirteen out of the 32 anti-HDV antibody-positive subjects were HDV RNA positive. Thus, 3.5% of HBsAg-positive subjects on Miyako Island were HDV RNA positive. Among the HDV RNA-positive subjects, liver function tests were within normal limits or were mildly abnormal. Nucleotide sequence analysis revealed that the HDV genomes on Miyako Island were similar to the Japanese and Taiwan isolates of HDV genotype II. Taiwan is geographically close to Miyako Island. Even though the races are different, a geographical factor was revealed to be significant with regard to HDV infection, which was spread in a closed environment.

Aged↗

PubMed1985

Bird remains from an archaeological site on Henderson Island, South Pacific: Man-caused extinctions on an "uninhabited" island.

Long thought never to have been inhabited and to be in a pristine ecological state, Henderson Island (southeast Pacific) is now known to have been colonized and then abandoned by Polynesians. Bones from an archaeological site on the island associated with (14)C dates of approximately 800 and approximately 500 years B.P. include specimens of 12 species of birds, of which 3, a storm-petrel and two pigeons (Nesofregetta fuliginosa, Ducula cf. aurorae or D. pacifica, and Ducula cf. galeata), no longer occur on Henderson, and two others (Puffinus nativitatis and Sula sula) still visit but are not known to breed. The vanished species were presumably exterminated by Polynesians and the biota of Henderson Island can thus no longer be regarded as being in an unaltered state. The prehistoric abandonment of various small, unarable islands by Polynesians may have been due to the depletion of seabirds and pigeons, the only readily available food source. The species of pigeons identified from Henderson are known historically only from distant archipelagos and have never before been found sympatrically. Distributional patterns resulting from man-caused extinctions may give rise to erroneous interpretations of the relationships and evolutionary history of insular organisms. Certain endangered species, such as Ducula galeata, might effectively be preserved by reintroduction to abandoned islands that they occupied before human intervention.

Journal Article↗

PubMed1992

An archipelago of CpG islands in Xq28: identification and fine mapping of 20 new CpG islands of the human X chromosome.

19 probes for CpG islands, mapping to Xq28, have been used as probes to construct a physical map of genes of this band of the human X chromosome. A total of 22 CpG islands have been precisely mapped in respect to known loci along the 9-10 Mb of Xq28. The fine mapping of such a large number of CpG islands has demonstrated that also in gene rich Giemsa light bands, like Xq28, gene distribution is non uniform: the CpG islands are clustered in the distal portion of the band in a 2 Mb region between the G6PD gene and the DXS15 locus. Moreover, 16 CpG islands were found between the G6PD and the RCP/GCP genes, a region of DNA of only about 300 kb. If this structural organization has a biological function it has yet to be determined. However, the isolation of large genomic regions enriched in gene sequences and the availability of cosmid or YAC contigs will provide the means to test the significance of such gene organization, as well as the material for large sequencing projects and gene search, for the identification of candidate genes for inherited disorders mapped to Xq28 and for comparative mapping.

Animals↗

PubMed2000

Tracking colonization and diversification of insect lineages on islands: mitochondrial DNA phylogeography of Tarphius canariensis (Coleoptera: Colydiidae) on the Canary Islands.

The genus Tarphius Erichson (Coleoptera: Colydiidae) is represented by 29 species on the Canary Islands. The majority are rare, single-island endemics intimately associated with the monteverde (laurel forest and fayal-brezal). The Tarphius canariensis complex is by far the most abundant and geographically wide-spread, occurring on Gran Canaria, Tenerife and La Palma. Eighty-seven individuals from the T. canariensis complex were sequenced for 444 bp of the mitochondrial DNA cytochrome oxidase I gene (COI), 597 bp of the COII gene and the intervening tRNA(leu) gene. A neighbour-joining analysis of maximum-likelihood distances put La Palma as a single monophyletic clade of haplotypes occurring within a larger clade comprising all Tenerife haplotypes. Gran Canarian haplotypes were also monophyletic occurring on a separate lineage. Using a combination of the phylogeographic pattern for T. canariensis, geological data, biogeography of the remaining species and estimated divergence times, we proposed a Tenerifean origin in the old Teno massif and independent colonizations from here to north-eastern Tenerife (Anaga), Gran Canaria and La Palma. New methods of estimating diversification rates using branching times were applied to each island fauna. All islands exhibited a gradually decreasing rate of genetic diversification similar to that seen for Brachyderes rugatus (Coleoptera: Curculionidae) from the Canary Islands.

Animals↗

PubMed2006

Yeast diversity sampling on the San Juan Islands reveals no evidence for the spread of the Vancouver Island Cryptococcus gattii outbreak to this locale.

Biological diversity has been estimated for various phyla of life, such as insects and mammals, but in the microbe world is has been difficult to determine species richness and abundance. Here we describe a study of species diversity of fungi with a yeast-like colony morphology from the San Juan Islands, a group of islands that lies southeast of Vancouver Island, Canada. Our sampling revealed that the San Juan archipelago biosphere contains a diverse range of such fungi predominantly belonging to the Basidiomycota, particularly of the order Tremellales. One member of this group, Cryptococcus gattii, is the etiological agent of a current and ongoing outbreak of cryptococcosis on nearby Vancouver Island. Our sampling did not, however, reveal this species. While the lack of recovery of C. gattii does not preclude its presence on the San Juan Islands, our results suggest that the Strait of Juan de Fuca may be serving as a geographical barrier to restrict the dispersal of this primary human fungal pathogen into the United States.

British Columbia↗

PubMed2006

Geographical distribution of the herpes simplex virus type 1 BgKL variant in Japan suggests gradual dispersion of the virus from Shikoku Island to the other Islands.

Restriction endonuclease fragment length polymorphism (RFLP) is useful for the epidemiological study of herpes simplex virus type 1 (HSV-1). We report here the identification of a major BglII RFLP variant of HSV-1, designated BgKL, found in 27.0% of 636 HSV-1 clinical isolates. We have also established its geographic distribution in Japan. BgKL has an unusually large BglII K fragment. SalI cleavage analyses showed that 97% of BgKL variant isolates lack both the SalI C-J and the F-J cleavage sites and have an unusually large SalI D or E fragment, and 91% of the BgKL variants lack both SalI G and H fragments. Furthermore, 96% of BgKL isolates have an unusually small KpnI M fragment. Therefore, BgKL is a marker for these five mutations in most HSV-1 isolates and is a useful HSV-1 RFLP marker. The BgKL variant was found in 59% of HSV-1 isolates from Shikoku Island, 44% of HSV-1 isolates from the Chugoku region of Honshu Island, 31% of HSV-1 isolates from Kyushu Island, 0% of HSV-1 isolates from Okinawa Island, 49% of HSV-1 isolates from Osaka, 27% of HSV-1 isolates from Shiga, 13% of HSV-1 isolates from the Chubu Region, and 9% of HSV-1 isolates from the Tohoku Region of Honshu Island. Differences in the frequency of BgKL between the Shikoku-Chugoku-Osaka area (49%) and Kyushu, between Kyushu and Okinawa, between the Shikoku-Chugoku-Osaka area and Shiga, and between Shiga and Tohoku are all statistically significant. The BgKL frequency decreases in a geographical gradient suggest that this HSV-1 variant was dispersed from Shikoku to the surrounding regions and then to more distant regions. The BgKL frequency in Tokyo was similar to the nationwide average. These are the first data to suggest a geographic and demographic dispersion pattern of HSV-1. Implications for the epidemiology and diversification of HSV-1 are discussed.

Bacterial Proteins↗

PubMed2003

Dental health of Chatham Islanders: an investigation of the oral health of Chatham Islands residents.

OBJECTIVES: To examine the self-reported and clinical oral health of Chatham Islanders. DESIGN: A cross-sectional oral health survey. SETTING: The Chatham Islands community. PARTICIPANTS AND METHODS: The investigation involved completion of dental self-report questionnaires by children who attended Chatham Islands schools, and adults who responded to a dental flyer. RESULTS: Eighty-seven children and 189 adults took part, all of whom had oral health examinations. Among the children, the prevalence of dental caries in the deciduous dentition was 67.8 percent, and the mean dfs, mean DFS and mean number of missing deciduous teeth due to caries were 5.9 (sd, 6.2), 0.5 (sd, 1.1) and 0.3 (sd, 0.8) respectively. Caries severity was higher in children who were episodic dental attenders, who had irregular brushing habits or whose dental experiences had had a negative impact on their lives. In adults, the prevalence of caries was 81.5 percent. The mean DFS and mean number of missing permanent teeth due to caries were 37.9 (sd, 13.1) and 4.7 (sd, 3.8) respectively. On average, caries severity was higher among infrequent and episodic dental attenders, irregular brushers and those for whom dental problems had had a negative life impact. CONCLUSIONS: While the oral health of Chatham Islands children is comparable with that of children in New Zealand, Chatham Islands adults may be dentally disadvantaged due to limited access to dental resources. The findings have important implications for the planning of dental health services for this remote area, and may provide a useful framework from which further investigations of remote community-dwellers' oral health may be developed.

Adolescent↗

PubMed2003

Application of multivariate analysis and artificial neural networks for the differentiation of red wines from the Canary Islands according to the island of origin.

Eleven metals (K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li, and Rb) were determined in 83 red wines from the Canary Islands. The wines presented high concentrations of Na, and the concentrations of Cu and Zn were much lower than the maximum concentrations established by the International Office of Vine and Wine (OIV). Applying principal component analysis, the dimension space was reduced to five principal components that explain 76.4% of the total variance, and the wines tend to separate on the basis of the island of production. Linear discriminant analysis (LDA) allowed a reasonable classification of wines according to the island of production. When artificial neural networks (Kohonen self-organizing maps and back-propagation feed-forward as unsupervised and supervised techniques, respectively) were applied on the matrix of data constituted by the analyzed metals, the results improved in relation to those obtained by other multivariate methods observing a differentiation of wines according to island of production.

Analysis of Variance↗

PubMed1988

Genetic variation in the Aleuts of the Pribilof Islands and the Eskimos of Kodiak Island.

A sample of Aleuts residing in the Pribilof Islands of St. Paul (N = 163) and St. George (N = 62) and Eskimo residents of Kodiak Island (N = 294) have been typed for genetic variation at 31 discrete genetic markers. Of these, 16 were polymorphic and 15 were monomorphic. Several private polymorphisms previously reported in Eskimo or Alaskan Amerindian populations were absent in both the Aleuts and Kodiak Island Eskimos. Genetic distance analysis shows considerable genetic differentiation between Aleuts and Kodiak Island Eskimos.

Alaska↗

PubMed2001

The Yersinia high-pathogenicity island: an iron-uptake island.

Highly pathogenic Yersinia carry a pathogenicity island termed high-pathogenicity island (HPI). The Yersinia HPI comprises genes involved in the synthesis of the siderophore yersiniabactin and can thus be regarded as an iron-uptake island. A unique characteristic of the HPI is its wide distribution among different enterobacteria such as Escherichia coli, Klebsiella, Citrobacter and Salmonella. Other types of iron-uptake systems are also carried by different pathogenicity islands in enterobacteria.

Animals↗

PubMed2006

Founder events as determinants of within-island and among-island genetic structure of Daphnia metapopulations.

The genetic structure of metapopulations offers insights into the genetic consequences of local extinction and recolonization. We studied allozyme variation in rock pool metapopulations of two species of waterfleas (Daphnia) with the aim to understand how these dynamics influence genetic differentiation. We screened 138 populations of D. magna and 65 populations of D. longispina from an area in the archipelago of southern Finland. The pools from which they were sampled are separated by distances between 1.5 and 4710 m and located on a total of 38 islands. The genetic population structure of the two species was strikingly similar, consistent with their similar metapopulation ecology. The mean F(PT) value (differentiation among pools with respect to the total metapopulation) was 0.55 and a hierarchical analysis showed that genetic differentiation was strong (>0.25) among pools within islands as well as among whole islands. Within islands, pairwise genetic differentiation increased with geographic distance, indicating isolation by distance due to spatially limited dispersal. Previous studies have shown strong founder events occurring during colonization in our metapopulation. We suggest that the genetic population structure in the studied metapopulations is largely explained by three consequences of these founder events: (i) strong drift during colonization, (ii) local inbreeding, which results in hybrid vigour and increased effective migration rates after subsequent immigration, and (iii) effects of selection through hitchhiking of neutral genes with linked loci under selection.

Animals↗

PubMed1988

CpG islands and HTF islands in the HLA class I region: investigation of the methylation status of class I genes leads to precise physical mapping of the HLA-B and -C genes.

We have investigated the accessibility of the 5' CpG rich sequences (CpG islands) present in the 5' region of most if not all HLA class I genes to methylation sensitive rare cutter enzymes. We show that for HLA-A, -B, -C genes and a few other (but not all) class I sequences these CpG islands are unmethylated and therefore constitute HTF islands (CpG rich, unmethylated regions of DNA, usually associated with expressed genes). We then map precisely the HTF islands of the HLA-B and HLA-C genes and determine that they are separated by 130 Kb (in agreement with genetic data) and that these two genes are in the same transcriptional orientation on the chromosome.

Chromosome Mapping↗

PubMed2005

Evidence for high-m secondary islands induced by large low-m islands in a tokamak plasma.

Small-scale structures with high poloidal mode numbers (m=10-20) have been observed in the TEXTOR tokamak plasma with pulsed radar reflectometry and an electron cyclotron emission diagnostic, in conjunction with large 2/1 and 1/1 islands. The small islands have a peaked density profile, similar to that of the simultaneously observed large-scale 2/1 islands. This together with the observation that high-frequency density and temperature fluctuations are very pronounced near the X points of the large islands hints to a strongly perturbed magnetic topology around the X points.

Journal Article↗

PubMed2005

Island colonization and founder effects: the invasion of the Guadeloupe islands by ship rats (Rattus rattus).

The stepwise colonization of islands within an archipelago is typically punctuated by successive founder effects, with each newly founded population being a subsample of the gene pool of the source island. Thus, the genetic signature of successive bottlenecks should be detected when analysing the genetic structure between islands of an archipelago. To test this prediction, we investigated introduced ship rat populations, Rattus rattus (Linnaeus, 1758), in the Guadeloupe Archipelago. Three different methods, commonly named the heterozygosity excess, the mode-shift indicator and the M ratio method, were used to detect bottlenecks from genetic data obtained with eight microsatellite markers on Guadeloupe and two neighbouring islands, Petite-Terre and Fajou. Moreover, a recent eradication failure on Fajou allowed us to test the accuracy of the methods in an 'experimental-like' situation. The results indicate that rats were introduced on Guadeloupe first, which then became the source population for independent secondary colonization of Fajou and Petite-Terre. Moreover, the heterozygosity excess and the mode-shift indicator only detected bottlenecks for the recent colonization of Petite-Terre and the eradication failure on Fajou. However, bottlenecks were detected for all the populations using the M ratio method. This could be interpreted as the remaining signature of the early introduction of the ship rat in the archipelago.

Alleles↗

PubMed2006

A physico-chemical survey of inland lakes and saline ponds: Christmas Island (Kiritimati) and Washington (Teraina) Islands, Republic of Kiribati.

The equatorial Pacific Ocean atoll islands of Kiritimati and Teraina encompass great physical, chemical and biological variability within extreme lacustrine environments. Surveys of lake chemistry and sediments revealed both intra- and inter-island variability. A survey of more than 100 lakes on Kiritimati found salinities from nearly fresh to 150 ppt with the highest values occurring within the isolated, inland portions of the island away from the influence of groundwater or extreme tides. Dissolved oxygen (DO) and pH values also showed considerable variability with a less regular spatial pattern, but were both generally inversely related to salinity. Series of lakes, progressively more isolated from marine communication, present a modern analog to the chemical and morphologic evolution of presently isolated basins. Sediments on both islands consist of interbedded red and green silt, possibly degraded bacterial mat, overlying white, mineralogenic silt precipitate. Variability may be indicative of shifts in climatological parameters such as the El Niño Southern Oscillation (ENSO) or the Pacific Intertropical Convergence Zone (ITCZ).

Journal Article↗

PubMed1993

[Seasonal distribution of chigger mites in the Kanghwa Island and Yongjong Island].

Seasonal distribution of chigger mites in the Kangwha Island and Yongjong Island was studied during the period of October 1992-August 1993. From 42 field rodents collected, 1,290 chiggers were obtained and 8 species of 4 genera were identified. In the Kanghwa Island, Leptotrombidium pallidum was the predominant species through all seasons with the percentage of 93.0%. Whereas, in the Yongjong Island, L. palpale was the predominant species with the percentage of 38.4% and L. pallidum was not found.

Animals↗

PubMed2003

Hematology and serum chemistry of the island spotted skunk on Santa Cruz Island.

We determined serum biochemistry and hematologic values for island spotted skunks (Spilogale gracilis amphiala) on Santa Cruz Island (California, USA). Samples were collected from island spotted skunks chemically restrained with ketamine hydrochloride and acepromazine in August 1999 (dry season) and from skunks manually restrained in August 2000 (dry season) and January 2001 (wet season). One parameter, glucose, significantly differed with season, with higher levels during the wet season. Serum chemistry and hematologic profiles suggest that method of restraint (manual or chemical), as well as other methodologic details, may influence blood characteristics in the island spotted skunk.

Acepromazine↗