Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Seychelles”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed1987

Retrovirus-associated myelopathies.

Human T-lymphotropic virus type I (HTLV-I), the causative agent of adult T-cell leukemia and non-Hodgkin's lymphoma (ATLL)--or a cross-reacting retrovirus--has been associated with tropical spastic paraparesis in Martinique, Jamaica, Colombia, Trinidad and Tobago, the Seychelles, and probably also in Zaire. The Caribbean basin and sub-Saharan Africa are endemic for ATLL. A similar etiology has been invoked in a chronic spastic myelopathy occurring in areas of high ATLL endemicity in Japan. An HTLV-I viral antigen has been demonstrated in cerebrospinal fluid lymphocytes of a Japanese patient with myelopathy. Human T-lymphotropic virus type I antibodies have occurred in patients in Florida and Japan (areas of HTLV-I endemicity) who were diagnosed as having clinically definite multiple sclerosis (MS), but not in patients with MS in other parts of the world. Human T-lymphotropic virus type I, like some lentiviruses--visna and human immunodeficiency virus, in particular--may be both lymphotropic and neurotropic. Tropical spastic paraparesis, the Japanese myelopathy, and, perhaps, an MS-like neurologic syndrome, may represent clinical variants of the same disease, a retroviral myelopathy.

Antibodies, Viral↗
PubMed1985

Tropical spastic paraparesis: a neuroepidemiological study in Colombia.

A geographic isolate of tropical spastic paraparesis (TSP) in Tumaco, Colombia, is described. Fifty confirmed cases were identified (29 men, 21 women) with an estimated prevalence ratio of 98 cases per 100,000 population. Patients with identified cases ranged in age from 24 to 75 years (mean, 46.5). TSP begins with burning feet, leg stiffness, spastic bladder, and, in men, impotence. Patients exhibited leg weakness, spasticity, hyperreflexia, and scissoring gait. Babinski, Chaddock, and Hoffmann signs could be elicited. Ankle reflexes and vibratory sensation of the feet were decreased. Intellectual function, coordination, and cranial nerves remained normal. TSP is a slowly progressive disorder but so far there have been no deaths from it. Forty cases in this report began between 1971 and 1980; the earliest documented case began in 1952. Living conditions and occupations of the patients were typical for the region. Yaws had occurred in 74% of confirmed cases. No likely etiological neurotoxic or nutritional factors were identified. TSP also has been described in India, Africa, the Seychelles, and Jamaica.

Adult↗
PubMed1987

Endemic tropical spastic paraparesis associated with human T-lymphotropic virus type I: a clinical and seroepidemiological study of 25 cases.

Tropical spastic paraparesis (TSP) is a common myeloneuropathy with primary and predominant involvement of the pyramidal tract and minimal sensory loss. The epidemic form of TSP is related to toxic nutritional factors, but the endemic form occurs in clusters in tropical areas, especially in India, Africa, the Seychelles, Colombia, and areas of the Caribbean. We describe the clinical and epidemiological features of 25 TSP patients from Martinique (French West Indies) with serum antibodies to human T-lymphotropic virus type I (HTLV-I). Furthermore, all 11 patients who were seropositive for HTLV-I had specific HTLV-I antibodies in their CSF. All were women. The age of onset varied from 25 to 60 years (mean, 45 years). The main clinical features are spastic paraparesis or paraplegia with spasticity of the upper limbs, minimal sensory loss, and bladder dysfunction. Minimal estimated incidence and prevalence are 1 per 100,000 inhabitants per year and 8 per 100,000, respectively. Seventeen percent of the relatives of patients with HTLV-I-associated TSP have HTLV-I antibodies (1 husband and 7 children). In Martinique, the prevalence of HTLV-I antibodies in the general population is about 2% and reaches 10% for neurological disorders other than TSP. Since our initial report, the association between spastic paraparesis and HTLV-I has been confirmed in Jamaica, Colombia, and Japan, suggesting the neurotropism of this lymphotropic human retrovirus.

Adult↗
PubMed1988

Tropical spastic paraparesis in Colombia.

A high-incidence focus of tropical spastic paraparesis (TSP) occurs on the South Pacific coast of Colombia. Of 55 patients studied, 52 (94.5%) had IgG antibodies to the human T-cell lymphotropic virus type I (HTLV-I) in serum and/or cerebrospinal fluid. Control groups did not show similar high positivity. Our results suggest that HTLV-I or other antigenically related retroviruses may be the cause of TSP in Colombia. Similar clinical, laboratory, and epidemiological findings have been reported in widely remote geographical regions of the world, with very similar clinical pictures of TSP in all high-incidence regions. The demonstration of IgG antibodies in serum and cerebrospinal fluid of patients with TSP in the Caribbean and Seychelles Islands, southern Japan, and the Ivory Coast indicate that the HTLV-I retrovirus could be the cause of this "tropical" myeloneuropathy.

Adolescent↗
PubMed1988

Epidemiology of tropical spastic paraparesis in Columbia and associated HTLV-I infection.

The clinical syndrome earlier designated as paraparesia espástica del Pacífico is an isolated form of tropical spastic paraparesis (TSP) that was reported in 1981 in the southern Pacific lowlands of Columbia in and near Tumaco. The clinical features are similar to those of TSP reported in Jamaica, Martinique, the Seychelles, and the Ivory Coast of Africa and resemble also those clinical features of the human T-lymphotropic virus type I (HTLV-I)-associated myelopathy described in southern Japan. Since HTLV-I infection is closely associated with TSP, we conducted a case-control study to evaluate the role of HTLV-I-associated risk factors among patients from the endemic focus in Tumaco, Colombia, and the seroprevalence rates of this virus in other geographical areas of the Pacific Colombian lowlands with and without TSP. From our seroprevalence study of antibodies to HTLV-I among TSP index patients, matched controls, household contacts (first- and second-degree relatives), and healthy controls from these areas, we found a strong association between HTLV-I and TSP. Also, there is a high seroprevalence of HTLV-I among sexual partners of patients and to a lesser extent among their offspring and other relatives some of whom had an early mean acquisition of antibodies to HTLV-I. Heterosexual promiscuity and other close interpersonal contact may play an important role in the transmission of TSP in the Pacific lowlands of Colombia.

Adolescent↗
PubMed1988

A clinical neurophysiologic study of tropical spastic paraparesis.

During a field study in the Seychelles Islands, 19 patients with tropical spastic paraparesis (TSP) were evaluated electrophysiologically. Methods of assessment included motor and sensory nerve conduction studies, electromyography, and analysis of the somatosensory evoked potentials after stimulation of the tibial and median nerves. The results showed that the most prominent feature of the disease, a spastic paraparesis, is accompanied by subclinical involvement of spinal sensory pathways and a comparatively minor peripheral sensorimotor polyneuropathy.

Electromyography↗
PubMed2003

Environmental exposure to mercury and its toxicopathologic implications for public health.

Mercury is a toxic and hazardous metal that occurs naturally in the earth's crust. Natural phenomena such as erosion and volcanic eruptions, and anthropogenic activities like metal smelting and industrial production and use may lead to substantial contamination of the environment with mercury. Through consumption of mercury in food, the populations of many areas, particularly in the developing world, have been confronted with catastrophic outbreaks of mercury-induced diseases and mortality. Countries such as Japan, Iraq, Ghana, the Seychelles, and the Faroe Islands have faced such epidemics, which have unraveled the insidious and debilitating nature of mercury poisoning. Its creeping neurotoxicity is highly devastating, particularly in the central and peripheral nervous systems of children. Central nervous system defects and erethism as well as arrythmias, cardiomyopathies, and kidney damage have been associated with mercury exposure. Necrotizing bronchitis and pneumonitis arising from inhalation of mercury vapor can result in respiratory failure. Mercury is also considered a potent immunostimulant and -suppressant, depending on exposure dose and individual susceptibility, producing a number of pathologic sequelae including lymphoproliferation, hypergammaglobulinemia, and total systemic hyper- and hyporeactivities. In this review we discuss the sources of mercury and the potential for human exposure; its biogeochemical cycling in the environment; its systemic, immunotoxic, genotoxic/carcinogenic, and teratogenic health effects; and the dietary influences on its toxicity; as well as the important considerations in risk assessment and management of mercury poisoning.

Environmental Exposure↗
PubMed2000

Twenty-seven years studying the human neurotoxicity of methylmercury exposure.

Research at the University of Rochester (U of R) has been focused on mercury for nearly half a century. Initially studies focused on dosimetry, especially the accuracy of measuring exposure, and experimental work with animal models. Clinical studies in human populations started when the U of R mercury group was asked to assist with dosimetry in the Iraq epidemic of 1971-1972. Initial clinical studies described the effects of methylmercury (MeHg) poisoning on adults and children. A dose-response curve for prenatal exposure was determined and it suggested that relatively low exposures might be harmful to the fetus. Since most human exposure to MeHg is dietary from fish consumption, these theoretical dangers had far-reaching implications. After Iraq, the Rochester team pursued exposure from fish consumption in both adults and children. Populations with high fish consumption were identified in Samoa and Peru for studying adults and in Peru and the Seychelles islands for studying children. The possible health threat to the fetus from maternal fish consumption quickly became the focus of research efforts. This paper reviews the Rochester experience in studying human exposure to MeHg from fish consumption.

Adult↗
PubMed2001

How useful is linear regression analysis in detecting the existence of dose-response relationships in large-scale epidemiologic studies when only a fraction of the population is sensitive? The case of methylmercury.

The existence of a dose response in epidemiologic studies is generally determined from the linear regression slope after controlling for covariates. This approach assumes the entire population is equally sensitive to the toxicant and that response is a function only of dose and a random error function. However, sensitive subpopulations have been identified for a variety of toxicants possibly including methylmercury (MeHg). The study of MeHg exposure in the Seychelles Islands has failed to find significant effects (dose-response slope not significantly different from zero) while other studies have found such effects. Using data on the error function in developmental test scores and MeHg exposure distributions from that study, and assuming plausible dose-response relationships for sensitive subpopulations, we conducted Monte-Carlo simulations of the power of linear regression analysis to detect a dose-response relationship from the total sample (n=700), and to compare dose-response slopes in the total and sensitive populations. Linear regression did not reliably detect a dose-response relationship for most scenarios when sensitives were 5% of the total and for some scenarios when sensitives were 10% of the total. We also found that the dose-response slope for the total population underestimated the sensitive dose-response slope in all cases by about an order of magnitude. These findings may have important implications for detection and quantification of dose-response relationships from epidemiologic studies.

Child↗
PubMed1993

Direct sequencing of genomic cDNA fragments amplified by the polymerase chain reaction for molecular epidemiology of dengue-2 viruses.

A nucleotide fragment encoding amino acids 29 to 94 in the E-protein of 28 dengue-2 isolates of diverse geographic and host origins was examined by direct sequencing of a polymerase chain reaction (PCR)-amplified product, and compared to six previously published sequences. Nucleotide divergence ranged from 0 to 19.8% corresponding to a maximum of 9% divergence in the amino acid sequence. Taking a divergence of 6% between the nucleotide sequence as a cut off for genotype classification, six groups have been established. Southeast Asian and the Jamaican 1983 genotypes show a high rate of similarity (> 95.2%). Our results suggest that virus of this group is now circulating as the dominant topotype in Brazil (1990) and in French Guyana (1986-1991). African strains fall into two groups, one endemic group (1970-1990) and one epidemic group (1986-1987). The three other groups correspond to viruses from Sri Lanka (1982) and the Seychelles (1977), from Puerto Rico (1973) and from Tahiti (1975). Our approach appears to be valuable characterizing dengue isolates, easily and rapidly.

Aedes↗
PubMed1991

Insertion sites of the transposable element mariner are fixed in the genome of Drosophila sechellia.

The abundance of the transposable element mariner differs dramatically in the genomes of the closely related species Drosophila simulans, D. mauritiana, D. sechellia, and D. melanogaster. Natural populations of D. simulans and D. mauritiana have 1-10 and 20-30 copies per diploid genome, respectively, and the insertion sites are polymorphic. The element has not been found in D. melanogaster. In this paper we show that D. sechellia, a species endemic to the Seychelles Islands, contains only two mariner elements that are at fixed sites in the genome. One element, inserted in chromosome 2R at 51A1-2, contains three deletions and is missing much of the 3' end. The other element, inserted in chromosome 3L at 64A10-11, is the full length of 1286 bp. Although the sequence of the full-length element is polymorphic in populations of D. sechellia, at least some of the sequences are closely related to elements from D. simulans and D. mauritiana that are known to be active. However, judging from the progeny of crosses between D. sechellia and D. simulans, the biological activity of the full-length D. sechellia element appears to be low, either because of the nucleotide sequence of the element or because of its position in the genome, or both.

Animals↗
PubMed2001

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings.

For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures. In many egg-laying animals, parental care of the offspring may continue while the eggs are incubating and also after they have hatched. Consequently, the importance of the nest site for determining incubation conditions may be reduced since the parents themselves may alter the local environment. By contrast, in marine turtles, parental care ceases once the eggs have been laid and the nest site covered. The positioning of the nest site, in both space and time, may therefore have profound effects for marine turtles by affecting, for example, the survival of the eggs and hatchlings as well as their sex (Janzen and Paukstis 1991). During incubation, sea turtle embryos grow from a few cells at oviposition to a self-sufficient organism at hatching some 50-80 days later (Ackerman 1997). After hatching, the young turtles dig up through the sand and emerge typically en masse at the surface 1-7 nights later, with a number of stragglers following over the next few nights (Christens 1990). This contrasts with the frequently observed pattern of hatching asynchrony in birds. It has been suggested that the cause of mass emergence in turtles is that eggs within a clutch are fertilised within a short period of time and then, when thermal conditions within the nest are uniform, develop at very similar rates and hence hatch and emerge together (Porter 1972). As a corollary of this idea, it would be predicted that when there are pronounced within-nest thermal gradients, development rates of siblings will be different and hence asynchronous hatching and emergence might occur. While it may be energetically beneficial for hatchlings to emerge in a group (Carr and Hirth 1961), if the extent of hatching asynchrony is marked then there may be severe costs for individuals if they wait for all their siblings to hatch before attempting to dig out of the sand (Hays and Speakman 1992). Under such conditions, the protracted emergence of small groups of hatchlings over several nights may be favoured. Examination of the literature suggests that emergence asynchrony may be more widespread than generally considered. For example, Witherington et al. (1990) described loggerhead turtle hatchlings (Caretta caretta) emerging over 4 days in Florida; for green turtles (Chelonia mydas), Hendrickson (1958) documented that nests in Malaysia and Sarawak produced hatchlings for up to 8 days; whilst Diamond (1976) found that hawksbill (Eretmochelys imbricata) nests on Cousin Island, Seychelles, were active for up to 4 days. Similarly, on the Greek Island of Kefalonia, we have shown that emergence from individual loggerhead turtle nests may occur on up to 11 nights (Hays and Speakman 1992). It is logical to suppose that asynchronous emergence relates to thermal gradients within nests, since the incubation duration of sea turtle eggs is related to temperature, with eggs hatching quicker when the temperature is higher. Here we test this hypothesis by measuring thermal variations within loggerhead turtle nests and comparing these variations to the patterns of hatchling emergence.

Animals↗
PubMed2003

Global pollution monitoring of PCBs and organochlorine pesticides using skipjack tuna as a bioindicator.

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

Animals↗
PubMed2005

The genetics of adaptation in Drosophila sechellia.

Drosophila sechellia is an island endemic of the Seychelles. After its geographic isolation on these islands, D. sechellia evolved into a host specialist on the fruit of Morinda citrifolia--a fruit often noxious and repulsive to Drosophila. Specialization on M. citrifolia required the evolution of a suite of adaptations, including resistance to and preference for some of the toxins found in this fruit. Several of these adaptive traits have been studied genetically. Here, I summarize what is known about the genetics of these traits and briefly describe the ecological and geographical context that shaped the evolution of these characters. The data from D. sechellia suggest that adaptations are not as genetically complex as historically thought, although almost all of the adaptations of D. sechellia involve several genes.

Adaptation, Biological↗
PubMed1988

Tropical spastic paraparesis. A clinical study of 50 patients from Tumaco (Colombia) and review of the worldwide features of the syndrome.

Tropical spastic paraparesis (TSP) is a chronic and slowly progressive endemic myelopathy occurring in geographical isolates in the Caribbean, South India, South Africa, the Seychelles, and Colombia. A detailed clinical and laboratory study was performed on 50 TSP patients from the island of Tumaco (Colombia), in a tropical rain forest area. Most patients were middle-aged blacks, 29 (58%) men and 21 women. In every case, neurological examination confirmed the presence of pyramidal signs in the lower limbs, plus, in 58%, moderate decrease in vibratory perception distally in the feet, bilaterally and symmetrically. Absent ankle jerks were found in 28%. Slow onset and chronic progression were documented in most patients. Positive treponemal serology, from yaws infection in childhood, was found in the serum in 92%, and in 19% also in the cerebrospinal fluid (CSF). No pleocytosis was documented on 27 CSF samples, but increased protein content occurred in 86%, with elevation of gamma-globulins in 78%. Treatment of 20 patients with high doses of penicillin produced no change in the clinical picture. TSP emerges from this review of the literature as a remarkably homogeneous clinical entity worldwide. A retrovirus-human T-lymphotropic virus type 1 (HTLV-1)--has been recently implicated as a possible etiology of the syndrome.

Adult↗
PubMedDate not supplied

HTLV-1 and tropical spastic paraparesis. 1. Clinical features, pathology and epidemiology.

The clinical profile of tropical spastic paraparesis (TSP), described in scattered tropical and subtropical territories over the past 30 years, has been more clearly defined since the discovery of its direct association with human T lymphotropic virus type 1 (HTLV-1). A chronic disease of adults, commoner in women, it usually presents as a progressive spastic paraparesis with sphincter disturbance, sometimes with backache and lower limb sensory disorder. Most cases are chair-bound within 10 years. Histology reveals a chronic lymphocytic meningomyelopathy, predominantly in the spinal cord, together with long tract demyelination and hyalinoid thickening of the media and adventitia of small blood vessels. Geographical areas of high prevalence of TSP are known in the Caribbean, South America, South Africa, southern Japan, the Seychelles and probably in India, and it is sparsely endemic elsewhere. The virus appears to exist within lymphocytes for long periods. Vertical transmission occurs postnatally, and sexual and transfusion infection are also recognized, but much remains to be clarified regarding its pathogenesis and epidemiology.

Brain Stem↗
PubMed1983

Genetic variation among dengue 2 viruses of different geographic origin.

Genetic variation in dengue 2 isolates from various geographic areas was examined by oligonucleotide fingerprinting of the 40 S genome RNA. Oligonucleotide maps of geographically isolated and epidemiologically unrelated viruses were very distinct. Direct comparison of the oligonucleotide map of the dengue 2 prototype New Guinea 2 virus, isolated in 1944, with the fingerprints of more recent isolates from the South Pacific indicated that the genome of dengue 2 virus had undergone extensive change although the viruses are serologically indistinguishable. The oligonucleotide map of an isolate from a recent case in Jamaica and a mosquito isolate from Upper Volta, Africa, were recognized to be almost identical, suggesting that virus may have been introduced into the Caribbean from West Africa. Likewise, the fingerprints of isolates from Puerto Rico and the South Pacific shared 80 to 95% of their large oligonucleotides, suggesting that the virus involved in these epidemics may have spread throughout Tahiti, American Samoa, Fiji, and to Puerto Rico in the Caribbean or vice versa. On the basis of these studies, five genetic variants or topotypes of dengue 2 virus have been established: (1) Puerto Rico-South Pacific, (2) Burma-Thailand, (3) the Seychelles, (4) the Philippines, and (5) Jamaica-West Africa. Oligonucleotide fingerprinting offers a highly sensitive and reproducible technical approach to the investigation of dengue 2 virus intratypic variation and possibly to the understanding of the biological variation associated with dengue fever and hemorrhagic disease.

Africa, Western↗
PubMed1996

Comparison of four human studies of perinatal exposure to methylmercury for use in risk assessment.

Newer data from human epidemiologic studies of methylmercury (MeHg) poisoning in which perinatal exposure occurred are available from four distinct populations. The results of an Iraqi grain-consuming population are compared to results from studies performed in fish-consuming groups in the Faroe Islands, the Seychelles Islands and in Peruvian fishing villages. A comparison of the results indicate that the Iraqi population does not represent a sensitive subpopulation within a perinatal group, but rather the relative lower threshold identified from this study was the results of confounders. Use of this benchmark dose for regulatory purposes may place a severe limitation upon fish consumption in the United States that is not fully supported by the scientific data.

Denmark↗