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At least 469 records · Page 26Linked to original sources
PubMed2003

LCR testing for gonorrhoea and chlamydia in population surveys and other screenings of low prevalence populations: coping with decreased positive predictive value.

OBJECTIVE: Nucleic acid amplification tests have facilitated field based STD studies and increased screening activities. However, even with highly specific tests, the positive predictive value (PPV) of such tests may be lower than desirable in low prevalence populations. We estimated PPVs for a single LCR test in a population survey in which positive specimens were retested. METHODS: The Baltimore STD and Behavior Survey (BSBS) was a population based behavioural survey of adults which included collecting urine specimens to assess the prevalence of gonorrhoea and chlamydial infection. Gonorrhoea and chlamydial infection were diagnosed by ligase chain reaction (LCR). Nearly all positive results were retested by LCR. Because of cost considerations, negative results were not confirmed. Predicted curves for the PPV were calculated for a single testing assuming an LCR test sensitivity of 95%, and test specificities in the range 95.0%-99.9%, for disease prevalences between 1% and 10%. Positive specimens were retested to derive empirical estimates of the PPV of a positive result on a single LCR test. RESULTS: 579 participants age 18-35 provided urine specimens. 20 (3.5%) subjects initially tested positive for chlamydial infection, and 39 (6.7%) tested positive for gonococcal infection. If positive results on the repeat LCR are taken as confirmation of a "true" infection, the observed PPV for the first LCR testing was 89.5% for chlamydial infection and 83.3% for gonorrhoea. This is within the range of theoretical PPVs calculated from the assumed sensitivities and specificities of the LCR assays. CONCLUSIONS: Empirical performance of a single LCR testing approximated the theoretically predicted PPV in this field study. This result demonstrates the need to take account of the lower PPVs obtained when such tests are used in field studies or clinical screening of low prevalence populations. Repeat testing of specimens, preferably with a different assay (for example, polymerase chain reaction), and disclosure of the non-trivial potential for false positive test results would seem appropriate in all such studies.

Adolescent↗
PubMed2006

A nationwide population-based study identifying health disparities between American Indians/Alaska Natives and the general populations living in select urban counties.

OBJECTIVES: Despite their increasing numbers, little is known about the health of American Indians/Alaska Natives living in urban areas. We examined the health status of American Indian/Alaska Native populations served by 34 federally funded urban Indian health organizations. METHODS: We analyzed US census data and vital statistics data for the period 1990 to 2000. RESULTS: Disparities were revealed in socioeconomic, maternal and child health, and mortality indicators between American Indians/Alaska Natives and the general populations in urban Indian health organization service areas and nationwide. American Indians/Alaska Natives were approximately twice as likely as these general populations to be poor, to be unemployed, and to not have a college degree. Similar differences were observed in births among mothers who received late or no prenatal care or consumed alcohol and in mortality attributed to sudden infant death syndrome, chronic liver disease, and alcohol consumption. CONCLUSIONS: We found health disparities between American Indians/Alaska Natives and the general populations living in selected urban areas and nationwide. Such disparities can be addressed through improvements in health care access, high-quality data collection, and policy initiatives designed to provide sufficient resources and a more unified vision of the health of urban American Indians/Alaska Natives.

Adolescent↗
PubMed1999

[Clinical epidemiology of primary hyperlipidemia in Japanese population, in comparison with western populations].

For the last years cardiovascular diseases are the major causes of deaths in Japan. The increase in the frequency of hyperlipidemia is thought to be the background factor of this trend. In this article, the characteristics of clinical epidemiology of hyperlipidemia in Japanese population will be reviewed, in comparison with the studies from Western populations. Regarding phenotypes, type IV hyperlipidemia is dominant in Japanese men, while type II is most frequent in Western populations. The differences in the serum cholesterol levels between Japanese population and Western one have got smaller year after year. The epidemiological study of hyper HDL cholesterolemia, which is characteristic of Japanese, will be also reviewed.

Adult↗
PubMed2000

[Population study of ischemic heart disease socio-psychological risk factors in male population of Novosibirsk].

AIM: To study a 5-year prevalence of and changes in anxiety, behavior of the coronary type, social support, health self-estimation, attitude to smoking, sleep disorders in male population. MATERIALS AND METHODS: In the context of the program "MONICA-psychosocial", a random representative sample of males aged 25-64 living in Novosibirsk has been examined (screening in 1988-1989--739 males, and in 1994-1995--657 males). RESULTS: Personal anxiety in the study population has increased for 5 years from 49.5 to 51%. The number of males with coronary behavior has reduced from 25.9 to 16.9% (p < 0.001). Health self-estimation has improved and frequency of sleep disorders diminished. Negative tendencies also manifested: less number of males quit smoking, social connections and contacts decreased. CONCLUSION: A close correlation between psychosocial factors and ischemic heart disease necessitate intensification of the preventive programs aimed at weakening of influence of psychosocial factors on the population. Otherwise no reduction in ischemic heart disease incidence in population can be expected.

Adult↗
PubMedDate not supplied

Self-perceived health among Canadian opiate users: a comparison to the general population and to other chronic disease populations.

BACKGROUND: There are an estimated 40,000 to 90,000 injection opiate users in Canada. The social, economic and health consequences of opiate addiction have been well documented. However, there are no data on the self-perceived health status of opiate users in Canada. Therefore, the goal of this research is to gain an understanding of the self-perceived health status of opiate users by comparing the health-related quality of life of opiate users to chronic disease populations and to the general population. METHODS: The SF-36 was administered to a nonrandom sample of 143 opiate users entering low-threshold methadone treatment. Two sample t-tests were performed to assess statistical differences, at a 5% level of significance, between population scores across SF-36 dimensions. RESULTS: Opiate users perceived both their mental and physical health as worse than the general population and individuals with minor and serious medical problems, but comparable to those with diagnosed psychiatric illnesses. CONCLUSIONS: Methadone treatment services should incorporate both primary care and psychiatric care into their programs, or at the very least secure appropriate referral mechanisms to ancillary services to ensure that the health concerns of opiate users are dealt with in the context of their treatment program.

Adult↗
PubMed2006

[Comparative study of the population structure and population assignment of sockeye salmon Oncorhynchus nerka from West Kamchatka based on RAPD-PCR and microsatellite polymorphism].

Using two types of molecular markers, a comparative analysis of the population structure of sockeye salmon from West Kamchatka as well as population assignment of each individual fish were carried out. The values of a RAPD-PCR-based population assignment test (94-100%) were somewhat higher than those based on microsatellite data (74-84%). However, these results seem quite satisfactory because of high polymorphism of the microsatellite loci examined. The UPGMA dendrograms of genetic similarity of three largest spawning populations, constructed using each of the methods, were highly reliable, which was demonstrated by high bootstrap indices (100% in the case of RAPD-PCR; 84 and 100%, in the case of microsatellite analysis), though the resultant trees differed from one another. The different topology of the trees, in our view, is explained by the fact that the employed methods explored different parts of the genome; hence, the obtained results, albeit valid, may not correlate. Thus, to enhance reliability of the results, several methods of analysis should be used concurrently.

Alleles↗
PubMed2006

[RHD 1227A allele frequency among Rh negative population and random population].

To investigate the frequency of RHD 1227A allele in Rh negative population and random population, an AS-PCR (allele specific-polymerase chain reaction) method was employed to detect RHD 1227A allele. RHD gene copy was determined by D zygosity test and RHD exon 9 nucleotide sequence analysis. The results showed that among 143 Rh negative donors, forty-one RHD 1227A allele carriers were detected, and 8 (19.51%) out of which were RhCCdee, 32 (78.05%) were RhCcdee, and 1 (2.44%) was RhCcdEe. Thirty-five Rh negative RHD 1227A carriers had RHD gene deletion, and the remaining carriers were RHD 1227A homozygous. Seven (1.43%) individuals were detected with RHD 1227A allele among 489 random donors. They were all G/A heterozygous at RHD 1227 site. Serological test indicated that they were normal Rh positive phenotype. It is concluded that the frequency of RHD 1227A allele is 16.43% among Rh negative population and 0.72% among the random population.

Asian People↗
PubMed1989

[Polymorphism of alpha1-antitrypsin in Pamir populations. Reproductive compensation--possible mechanism for maintaining genetic diversity gor PI genes in human populations].

The distribution of the phenotype and gene frequencies of alpha 1-antitrypsin among Pamir's aborigines localized at high altitudes was studied. The Kirghizes of Murgab studied include mainly the mongoloid component in their composition. Populations of the Khuf river valley in West Pamir anthropologically belong to South caucasoids. The following frequencies of PI genes have been registered in Kirghizes (N = 102): M1 = 0.6961, M2 = 0.2108, M3 = 0.0539, Z = 0.0245, I = 0.0049, S = 0.0049, N = 0.0049; in the Khuf population (N = 122): M1 = 0.7910, M2 = 0.0943, M3 = 0.0984, Z = 0.0082, I = 0.0041, S = 0.0041; in the Pastkhuff population (N = 38): M1 = 0.7237, M2 = 0.1579, M3 = 0.1053, Z = 0.0132. A parallele biodemographic investigation in the Murgab population showed that couples, with one of the partners carrying the rare variant of PI demonstrated statistically significant increase in successful outcomes of pregnancies. The same cohort has displayed lower infant mortality rates, the absence of miscarried fetus and stillborn babies. Our results point to the possible existence of a mechanism of reproductive compensation serving to uphold the genetic diversity of PI genes.

Asian People↗
PubMed1985

[Comparative study of the prevalence of Herpesviridae in an African population and a European population].

We have looked for long-term antibodies to Herpesviridae (HSV, VZV, CMV, EBV) in an African population (suburban area of Dakar, Senegal, West Africa) and in a European population (urban area of Bordeaux, France) in order to determine the prevalence of these viruses. The studied sera have been dispatched into 5 age-groups: 6 months to 4 years, 5 years to 9 years, 10 years to 14 years, 15 years to 44 years and greater than 45 years. We note that primary infection with Herpesviridae occurs sooner in life in Africa and that the prevalence rates of these viruses are higher in Africa with the exception of EBV, the prevalence of which is almost identical within the fifth age-group of the African and European populations. The prevalence rates of each individual virus are in agreement with previous studies except for VZV which we describe as the least prevalent virus of the family. The interest of this work is a simultaneous comparison of the prevalence of all viruses of the family Herpesviridae within two different populations.

Adolescent↗
PubMed1985

Population studies on PLG group system in the Polish population.

Distribution of PLG types was studied in a sample of the Polish population numbering 230 subjects by the method of high-voltage agarose electrophoresis. Of three phenotypes encountered, PLG1, appeared with the frequency of 0.4870, PLG2-1 with 0.4391 and PLG2 with 0.0739. Assuming the hypothesis of PLG controlled by 2 alleles the frequencies of genotypes were calculated as follows: for PLG1 gene -0.71 and for PLG2 gene -0.29. PLG system in the Polish population was confirmed to be in a state of genetic equilibrium. The frequencies of PLG genes in the Polish population do not deviate from the frequencies encountered in other European populations.

Blood Group Antigens↗
PubMed1983

The effect of steroids on the circulating lymphocyte population. V. Effect of prednisolone treatment on cell size and life span of the thoracic duct lymphocyte population in normal and neonatally thymectomized rats. A radioisotope study.

Using 3H-TdR isotope labelling in vivo, the effect of a high corticosteroid dose was correlated to cell size and life span of thoracic duct lymphocytes in rats. The lymphocytopenia in thoracic duct lymph during the involution phase (3 hrs after treatment) was a marked depletion of small lymphocytes, followed by a restitution to pretreatment cell levels within one day. The original lymphocyte population had a higher per cent of labelled small lymphocytes (50%) in comparison to the returning population which contained fewer (35%) small labelled cells. Label index (i.e. labelled cells of a certain cell size in percent of total cell number) was unchanged for all cell sizes during both involution and restitution phases. This unchanged label index profile as well as an earlier described unchanged cell size distribution support the hypothesis of lymphocyte trapping and redistribution as a major effect of a single prednisolone dose. The decrease of labelled small lymphocytes in the returning cell population can, however, also agree with a minor lymphocytolytic effect on circulating small lymphocytes. Our data do not support the hypothesis of two different lymphocyte populations with different life span. Neither could a redistribution of lymphocytes be found in any lymphoid tissue compartment or in femur bone marrow, during the involution phase after corticosteroid treatment.

Animals↗
PubMed1995

Benign marrow progenitors are enriched in the CD34+/HLA-DRlo population but not in the CD34+/CD38lo population in chronic myeloid leukemia: an analysis using interphase fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) was used to discriminate between benign and malignant cells in sorted populations of chronic myelogenous leukemia (CML) marrow. FISH has the advantage of allowing for a cell by cell analysis of the breakpoint cluster region (BCR) gene rearrangement immediately after flow sorting in nondividing G0/G1 cells that are potentially transcriptionally inactive. We initially selected CD34+ cells with very low expression of the activation antigen CD38 as a candidate phenotype for an immature and hypothetically more benign cell population, but found no enrichment for Ph negativity in that subtype. In five CML samples, 55% +/- 3.3% (mean +/- SE) of CD34+/CD38hi cells had the BCR gene rearrangement, similar to 57% +/- 3.7% seen in the CD34+/CD38lo population. In contrast, subsequent experiments (n = 4) determined that the CD34+/HLA-DRlo population in CML marrow does contain an increased proportion of benign cells: 15% +/- 1% of the CD34+/DRlo cells were BCR rearranged, compared with 52% +/- 5.8% of the CD34+/DRhi cells (P = .001). Our results indicate that benign progenitors in CML are enriched within the CD34+ cells with low DR antigen expression, but not low CD38 expression. One possible interpretation of these observations is that low CD38 antigen expression is not as useful as low HLA-DR expression for isolating immature cells.

ADP-ribosyl Cyclase↗
PubMed1997

Risk factors for coronary heart disease in a population with a high prevalence of obesity and diabetes: a case-control study of the Polynesian population of Western Samoa.

OBJECTIVE: To evaluate anthropometric, haemodynamic and biochemical risk markers for coronary heart disease (CHD) in the Polynesian population of Western Samoa in a case-control study of 43 cases of CHD compared with 90 age- (mean 53 years) and sex-matched controls. METHODS: Cases were identified on the basis of a 12-lead electrocardiogram and clinical history. RESULTS: More than 60% of the participants had a body mass index > or =30 kg/m2 and nearly 80% had central obesity. Both diabetes mellitus (17%) and impaired glucose tolerance (9%) were also common in this population. Nineteen per cent of the population were hypertensive and both antihypertensive therapy (21 versus 1%, P<0.001, risk 23.6) and hypertension (35 versus 11%, P<0.01, risk 4.3) were significantly more common among cases than they were among controls. In addition, the plasma high-density lipoprotein cholesterol level was lower (1.00+/-0.09 versus 1.24+/-0.05 mmol/l, P<0.05) and the plasma urate level was higher (0.42+/-0.02 versus 0.37+/-0.01 mmol/l, P<0.05) in the female cases than they were in their respective controls. Low-density lipoprotein (LDL) particle sizing did not reveal an excess of small LDL particles to be a feature of CHD cases, but more than 70% both of cases and of controls had multiple LDL species. The response of the triglyceride level to a fat-rich meal was the same for CHD cases and controls. CONCLUSION: The population studied had a high prevalence of several risk factors for CHD, including obesity and non-insulin-dependent diabetes mellitus; however, the most prominent factor relating to CHD within the community was the presence of hypertension.

Adult↗
PubMed1998

[The population-demographic structure and the prevalence of multifactorial diseases affecting the viability of the population of Kursk region].

A significant effect of the population structure on the incidence of multifactorial diseases affecting the viability of the adult population was found in rural districts of Kursk oblast. The diseases studied were chronic bronchitis, pulmonary emphysema, pneumosclerosis, and atherosclerosis. The incidence of multifactorial pathology increased with an increase in the homozygosity level of district populations. On average, the population structure affected the incidence of multifactorial diseases by 30-50%.

Adult↗
PubMed2003

Founder population size and number of source populations enhance colonization success in waterstriders.

Understanding the factors that underlie colonization success is crucial both for ecological theory and conservation practices. The most effective way to assess colonization ability is to introduce experimentally different sets of individuals in empty patches of suitable habitat and to monitor the outcome. We translocated mated female waterstriders, Aquarius najas, into 90 streams that were not currently inhabited by the species. We manipulated sizes of propagules (from 2 to 16 mated females) and numbers of origin populations (one or two). Three origin populations were genetically different from each other, but they were less than 150 km from the streams of translocation. The results demonstrate clearly that both the larger propagule size and the high number of source populations have positive effects on the probability of colonizing a new stream. Thus, in addition to the stochastic factors related to the propagule size it may be essential to consider also the diversity of genetic origin for colonization success.

Animals↗
PubMed2000

Emergence of individual behaviour at the population level. Effects of density-dependent migration on population dynamics.

The aim of this work is to study the effects of different individual behaviours on the overall growth of a spatially distributed population. The population can grow on two spatial patches, a source and a sink, that are connected by migrations. Two time scales are involved in the dynamics, a fast one corresponding to migrations and a slow one associated with the local growth on each patch. Different scenarios of density-dependent migration are proposed and their effects on the population growth are investigated. A general discussion on the use of aggregation methods for the study of integration of different ecological levels is proposed.

Animals↗
PubMed1998

[Phlebotomines of Senegal (Diptera: Psychodidae): population and population dynamics of the Mont-Rolland region].

Phlebotomine sandflies were captured on a monthly basis from May 1995 to April 1996 in the Mont-Rolland district in Western Senegal. The objectives were to study the population dynamics of sandflies and to make an inventory of the viruses they transmit. Among 10,315 specimens captured, belonging to 14 species, Sergentomyia dubia (35.9%), S. schwetzi (27.7%) and S. buxtoni (24.5%) were the most abundant. Species from the genus Sergentomyia accounted for 99.6% versus 0.4% for the genus Phlebotomus. The sandflies population was observed to peak in February. The most populated resting sites of the captured insects were in decreasing order tree-holes, termite-hills and burrows. S. dubia was the most abundant species captured in tree-holes. It was S. buxtoni in termite-hills, while S. schwetzi was found to dwell most often in burrows. No virus was isolated from 2,114 specimens tested.

Animals↗
PubMed2004

Demographic theory of coral reef fish populations with stochastic recruitment: comparing sources of population regulation.

The effects of three forms of density-dependent regulation were explored in model coral reef fish populations: top-down (predation), bottom-up (competition for food), and pelagic (non-reef-based mechanisms) control. We describe the demographic responses of both biomass and numbers of adult fish, predicting the mean and the variance of temporal fluctuations resulting from stochastic recruitment of juveniles. We find that top-down control acts by suppressing variability of numbers of fish, which in turn suppresses the variability of biomass. Bottom-up control has no effect on fluctuations of numbers of fish, though it strongly reduces fluctuations of biomass. Because fecundity of fish is directly linked to body mass, the regulation of biomass tightly regulates reproductive output independently of the number of individuals in the population. Finally, populations under pelagic control experience bounded fluctuations of biomass and numbers directly proportional to the bounded fluctuations of recruitment. The demographic signatures predicted from both bottom-up and pelagic control are consistent with current evidence supporting the recruitment limitation hypothesis in reef fish ecology. We propose tests to discriminate the dominant mode of density-dependent regulation using qualitative trends in time series demographic data across environmental clines.

Animals↗