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PubMedDate not supplied

Campylobacter colonization of the crops of newly hatched leghorn chicks.

We have studied colonization of crops in newly hatched leghorn chicks (a layer breed) by wild-type and mutant strains of Campylobacter jejuni. We established that the wild-type parent strain forms a stable population level within the crop and that the mutant strains will do likewise. Concentrations of mutant strains in the crop were usually below that of the wild-type parent strain and ranged from 10(3) to 10(5) colony-forming units. These results differ from results we have previously reported concerning cecal colonization, where these same mutant strains lacked colonizing ability. The present results, therefore, indicate that bacterial factors necessary for colonization of the crop are not the same as those needed for colonization of the cecum.

Animals↗
PubMed1979

Characteristics of men most likely to respond to an invitation to be screened.

Some of the characteristics of men, with known risk factors, who were most likely to respond to an invitation to be screened in a national randomized clinical trial to prevent heart disease were determined in 18,872 men, 35-57 years of age, members of the Kaiser Foundation Health Plan of Oregon. Demographic characteristics and risk factor variables (blood pressure, blood cholesterol, and cigarette smoking levels) were abstracted from medical records. The men were ranked high priority or low priority according to level of risk. All age-eligible men in the health plan received at least one invitation to be screened, with high-priority men receiving more invitations. Despite concentrated efforts to bring them in, less than one-half the high-priority men were screened. Participants were older and wealthier than non-participants, and more likely to have more dependents and to routinely use medical services. Whether or not a man received a medical care service within the preceding two years was a powerful discriminating variable in both the univariate and multivariate analyses reported. The findings suggest that health care programs serving a stable population group should give more consideration to screening in routine medical care.

Adult↗
PubMed2001

Results of the expanded program on immunization in the Macedonian refugee camps.

OBJECTIVES: This report summarizes the results of the Macedonian refugee camps' Expanded Program on Immunization. METHODS: Government agencies and nongovernmental organizations implemented an immunization program consisting of 3 mass vaccination campaigns in each of the 7 camps. Before the second mass campaign, weekly immunization clinics were initiated in each camp. Children younger than 48 months were immunized against 8 antigens according to a schedule established by the Macedonian Ministry of Health. RESULTS: Immunization coverage rates in the second campaign were 91% in Cegrane and 73% in Brazda. Coverage rates of the weekly clinics averaged 93%. CONCLUSIONS: Initiating an expanded immunization program in the absence of a stable population is problematic.

Child, Preschool↗
PubMed2001

Genetic approaches for antigen-selective cell therapy.

Attempts to improve the efficacy of adoptive T-cell therapies have led to the development of innovative strategies that combine the high specificity of antibody molecules with the efficient trafficking properties and effector functions of immune cells. These antigen-selective cell therapies are designed to convert therapeutically important native antigens expressed on the cell surface (tumor associated antigens, viral envelope proteins) into recruitment points of effector functions, and address the goal of major histocompatibility complex- and exogenous cytokine-independent activation of mature effector T-cells. The most promising and best characterized antigen-selective strategy is based on the genetic manipulation of the recognition specificity of T-cells by grafting the recognition specificity of a monoclonal antibody onto a lymphocyte triggering molecule (TCR-associated polypeptides, Fc epsilon RI-gamma chain). Upon encountering specific antigen, cells harboring chimeric immune receptors (CIRs) are able to undergo specific stimulation and kill antigen bearing cells in both in vitro and in vivo model systems. Initial studies have focused on terminally differentiated effector cell-based protocols. However, recent data indicate that progenitor cell-based therapies allow the permanent generation of stable populations of CIR-expressing cells of multiple lineages, leading to long-term persistent systemic immunity. Emerging gene therapy strategies are based on the use of biespecic antibody fragments. The advantages of these biespecic antibody-mediated immune recruitment (BIR) approaches (trans-recruitment and multieffector activation) could complement conventional CIR-based immunotherapies. Although further scientific progress is required regarding the selection of the ideal effector cell/s and the definition of the optimal targeting and recruitment systems, clinical trials recently initiated in patients with advanced cancer and human immunodeficiency virus infection should help us to determine the real efficacy of these approaches. The relevance of these and other emerging concepts to cell-mediated immunotherapy is discussed.

Antibodies, Bispecific↗
PubMed1986

Factor structure of shortened Children's Embedded Figures Test for different age groups.

240 children, 24 of each sex in Grades K to 4, were administered the entire Children's Embedded Figures Test, regardless of the failure rule. Factor loadings for items from a shortened version of the test were examined for a randomly divided sample, a sample divided by sex, a sample divided in two grade groupings, and an undivided total population. Stable factors were found for the total sample and when the sample was divided by sex. Analysis indicated that the factor analysis of the shortened form was consistent with previous analyses using the total scale.

Child↗
PubMed2003

Salmonella enteric infections in Gipuzkoa, Spain, 1983-2000.

The incidence of Salmonella enteric infections in Gipuzkoa, Spain, was estimated by studying a stable population between 1983 and 2000. Only stool culture confirmed cases were included. The annual mean rate of infection in children under 2 years old was 1121 per 100,000 (CI 95%; 1060-1181). This age group had the highest relative risk (RR), 16.2-fold higher than the RR of those aged over 14 years. Salmonella Enteritidis was the most prevalent serovar (80.4% of all patients), followed by Salmonella Typhimurium (11.7%).

Adolescent↗
PubMed1990

Bile reflux and the gastric mucosa: an experimental ferret model.

To study the effects of chronic bile reflux on the mammalian gastric mucosa, the ferret model was chosen for its practical aptitude and for its similarity to human gastric anatomy and physiology. A technique was first perfected for endoscopically directed gastric mucosal biopsy in the ferret. Subsequently, a surgical model of maximal enterogastric reflux (MR) and a control model of minimal reflux or "nonreflux" (NR) were developed. A stable population of 9 MR and 9 NR ferrets surviving 1-3 years has been established. All 18 animals, plus 6 nonoperative control animals, have undergone multiple repeat endoscopy and gastric biopsy without complication. The surgical and endoscopic techniques, with preliminary findings, are described.

Anastomosis, Roux-en-Y↗
PubMedDate not supplied

Anti-telomerase therapy suppressed glioma proliferation.

In order to determine if telomerase activity contributes to the growth of glioma cells, we constructed an anti-telomerase vector to suppress telomerase expression in glioma cells. The human telomerase (hTR)-antisense vector showed a significant suppression effect. However it did not appear to induce cell death as a stable population of cells survived more than two months following transfection. These results provide evidence that reagents aimed at inhibiting telomerase may represent a useful strategy for suppressing the growth of glioma cells. In addition to telomerase, another mechanism would also maintain telomere length, thus supporting continuous cell proliferation.

Cell Division↗
PubMed2000

Functional responses and costimulator dependence of memory CD4+ T cells.

To examine the functional characteristics of memory CD4+ T cells, we used an adoptive transfer system to generate a stable population of Ag-specific memory cells in vivo and compared their responses to Ag with those of a similar population of Ag-specific naive cells. Memory cells localized to the spleen and lymph nodes of mice and exhibited extremely rapid recall responses to Ag in vivo, leaving the spleen within 3-5 days of Ag encounter. Unlike their naive counterparts, memory cells produced effector cytokines (IFN-gamma, IL-4, IL-5) within 12-24 h of Ag exposure and did not require multiple cycles of cell division to do so. Memory cells proliferated at lower Ag concentrations than did naive cells, were less dependent on costimulation by B7 molecules, and independent of costimulation by CD40. Furthermore, effector cytokine production by memory cells also occurred in the absence of either B7 or CD40 costimulation. Lastly, memory cells were resistant to tolerance induction. Together, these findings suggest that the threshold for activation of memory CD4+ cells is lower than that of naive cells. This would permit memory cells to rapidly express their effector functions in vivo earlier in the course of a secondary immune response, when the levels of Ag and the availability of costimulation may be relatively low.

Adoptive Transfer↗
PubMedDate not supplied

The HMO as a health promotion laboratory.

HMOs offer unparalleled opportunities as a setting for health promotion research while providing the health care system with direct and immediate benefits. The special advantages of doing health promotion research in an HMO include easy access to a large, relatively stable population; access to all aspects of the health care system; access to a unified, comprehensive medical record; and working within an organization that views health promotion activities as an essential part of its mission. This article reviews these advantages and illustrates how they have been used in a diverse series of research and demonstration projects conducted within the Northwest Region of Kaiser Permanente.

Data Collection↗
PubMed1999

Intranasal exposure to protein antigen induces immunological tolerance mediated by functionally disabled CD4+ T cells.

In this study we examined the immunological parameters underlying the natural immunity to inhaled nonpathogenic proteins. We addressed this question by examining the effect of intranasal exposure to OVA in both wild-type mice and mice reconstituted with OVA-TCR transgenic CD4+ T cells. Intranasal administration of OVA induced an initial phase of activation during which CD4+ T cells were capable of proliferating and producing cytokines. Although many of the OVA-specific CD4+ T cells were subsequently depleted from the lymphoid organs, a stable population of such T cells survived but remained refractory to antigenic rechallenge. The unresponsive state was not associated with immune deviation due to selective secretion of Th1- or Th2-type cytokines, and the presence of regulatory CD8+ T cells was not required. Moreover, neutralization of the immunosuppressive cytokines IL-10 and TGF-beta did not abrogate the induction of tolerance. Inhibition of the interaction of T cells with CD86, but not CD80, at the time of exposure to intranasal Ag prevented the development of unresponsiveness, while selective blockade of CTLA-4 had no effect. Our results suggest that intranasal exposure to Ags results in immunological tolerance mediated by functionally impaired CD4+ T cells via a costimulatory pathway that requires CD86.

Abatacept↗
PubMed1975

Birth trajectory under changing fertility conditions.

An initially stable population of women is assumed to shift its reproductive behavior to a different level either abruptly or in a prescribed gradual fashion. A closed-form solution which is exact up to about 30 years after the reproductive adjustment is found for the resulting birth trajectory. Exact expressions are also found for the long-time asymptotic behavior of both the birth trajectory and the total population size when the shift in reproductive behavior is to bare replacement level. Accurate approximations to these asymptotic results are then derived and used to illustrate why a growing population continues to grow even after shifting to bare replacement reproductive behavior.

Age Factors↗
PubMed2001

A rapid assessment study on prevalence of substance abuse disorders in metropolis Delhi.

BACKGROUND & OBJECTIVES: No studies in India have attempted to identify in the general population a 'dependent drug user' based on clinically used diagnostic criteria. This two point survey estimated the prevalence of substance use disorders and the change in the trends of drug use after a period of one year in metropolis Delhi. METHODS: A total of 72 colonies in five types of housing clusters were surveyed. The head of the household (HOH) was interviewed only for collecting information about family members (above 10 yr) on an instrument based on the DSM III R operationalised criteria. Trained non medical interviewers administered the precoded instrument to 6004 and 5599 HOH in the first and second surveys respectively. RESULTS: In the first survey, the prevalence of tobacco, alcohol, cannabis and opioids use among males was 27.6, 12.6, 0.3 and 0.4 per cent respectively. The rates were highest in resettlement clusters followed by urban villages, unauthorized, regularized and in 'others' clusters. The use rates remained unchanged during the re-survey. Dependent use (any drug) increased in the resettlement clusters only during the re-survey. INTERPRETATION & CONCLUSION: The results highlight that it is the legal drugs viz., tobacco and alcohol that could pose higher health and social consequences, both short and long term. The situation of illicit drug use (heroin) was higher in the resettlement clusters and urban villages. Need based programmes have to be evolved and executed to keep the drug dependent population stable. The rapid survey technique can be useful in developing countries like India, where resource crunch for survey research is acute. This technique is less costly, quicker to perform and can supplant traditional self-report methodologies.

Adolescent↗
PubMed1975

Effect of the Aswan High Dam on prevalence of schistosomiasis in Egypt.

An increase in the prevalence of schistomiasis in Egypt, as a result of the Aswan High Dam, has for long time been predicted because of reclamation of land and conversion of annual flooding (basin irrigation) into perennial irrigation in Upper Egypt. Two aspects, neglected in the predictions, have been investigated in the present study, and these are: the ecological changes, relevant to the transmission of the disease, in the Nile itself, and those in irrigation canals and drains in areas which had been under perennial irrigation before the constriction of the dam. The findings indicate that the Nile, at least in the Delta, has become a favorite habitat for breeding of the snail hosts of both urinary and intestinal schistosomiasis, a center for human activities and evidently for transmission, and that irrigation canals and drains now harbor throughout the year undisturbed and stable populations of these snail hosts. This has resulted from the elimination in these canals, of the so-called 'winter closure', because it is no more needed. Before the dam the closure was enforced for about 40 days, during which the canals were closed and dried up, and the silt deposited on their beds during the Nile flood dredged out together with the snails and aquatic weeds.

Animals↗
PubMed1982

Construction of the new United Nations model life table system.

Previous systems of model life tables were based on empirical data from the now developed countries (the Coale and Demeny models) or, when patterns from less developed countries were included (the original UN set and the Lederman set), included data of poor or unknown quality. However, with the advent of new demographic techniques of data evaluation and of improved survey, census, and vital registration systems, it has become possible to construct a new model life table system based on reliable data from less developed countries and hence more applicable to demographic analysis within that milieu. The new UN model life tables are based on carefully evaluated age-sex specific mortality data found in developing countries. Analysis of these data indicated 4 major age patterns of mortality. These patterns have been labelled the Latin American pattern, the Chilean pattern, the South Asian pattern, and the Far Eastern pattern, according to the geographical region predominant in each pattern. An overall average pattern, labelled the general pattern, has also been constructed. Along with the model life tables themselves, the UN is also producing models of sex differences in life expectancy, single-year mortality, and stable populations. A manual of computer programs to facilitate use of these models is also being prepared.

Africa↗
PubMedDate not supplied

A study of digit preference and quality of age data in Turkish censuses.

The authors study digit preference and the quality of age data in the 1945, 1955, and 1970 censuses of Turkey. "Using the age distributions in successive censuses and particular cohort groups as well as the analysis of stable population, severe misreporting of certain ages was found. The...age data seem to be influenced substantially by both response errors and coverage errors....[and] show heaping at ages ending in zero and five years. The pattern of heaping is pronounced from age 20 onwards and this is true both for males and females. Various analyses showed clear evidence of heaping in all the three censuses at the age group 40-44 years irrespective of sex. The magnitude of digit preference bias seems to be reducing with the passage of time. This is especially true in the case of females. The possibility of increased female literacy as a factor underlying this reduction is pointed out. Other implications of the results are discussed." (SUMMARY IN FRE AND ITA)

Age Factors↗
PubMed1997

Birth trends, survival improvements, and aging.

"Decompositions of a change in the proportion of aged persons on the basis of the stable population theory [have] emphasized the contribution of fertility change. This study confirmed that cohort survival improvements largely contributed to changes in the proportion of aged persons and the average age since the late 1970s. Particularly, the cohort survival effects for those belonging to the age group 65+ at the time concerned was great." The geographical focus is on Japan.

Adult↗
PubMed2003

The global burden of diarrhoeal disease, as estimated from studies published between 1992 and 2000.

Current estimates of the global burden of disease for diarrhoea are reported and compared with previous estimates made using data collected in 1954-79 and 1980-89. A structured literature review was used to identify studies that characterized morbidity rates by prospective surveillance of stable populations and studies that characterized mortality attributable to diarrhoea through active surveillance. For children under 5 years of age in developing areas and countries, there was a median of 3.2 episodes of diarrhoea per child-year. This indicated little change from previously described incidences. Estimates of mortality revealed that 4.9 children per 1000 per year in these areas and countries died as a result of diarrhoeal illness in the first 5 years of life, a decline from the previous estimates of 13.6 and 5.6 per 1000 per year. The decrease was most pronounced in children aged under 1 year. Despite improving trends in mortality rates, diarrhoea accounted for a median of 21% of all deaths of children aged under 5 years in these areas and countries, being responsible for 2.5 million deaths per year. There has not been a concurrent decrease in morbidity rates attributable to diarrhoea. As population growth is focused in the poorest areas, the total morbidity component of the disease burden is greater than previously.

Child, Preschool↗