Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Population Control”

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 109 records · Page 6Linked to original sources
PubMedDate not supplied

Symptoms of oesophageal reflux are more common following laparoscopic cholecystectomy than in a control population.

Previous studies have shown that up to 40 per cent of patients have symptoms after cholecystectomy or laparoscopic cholecystectomy (LC). There are concerns, however, that these symptoms reflect those of the general population and are not a specific post-operative phenomenon. Abdominal symptoms of 212 patients following LC were compared to a healthy acalculous control population (n = 62). Patients and controls were assessed by questionnaire. Age and sex profiles were similar in both groups. There was no significant difference in the incidence of abdominal pain, bloating or nausea between the 2 groups. Frequent heartburn was a symptom in 19.3 per cent of patients following LC as compared to 3.2 per cent of control patients (p = 0.004, chi-squared 9.39, 1 d.f.). Furthermore 11.3 per cent of post-operative patients complained of dysphagia versus 6.4 per cent of the control group (p = 0.08, chi-squared 1.245, 1 d.f.). One hundred and twenty (57.1 per cent) patients judged their operation to be a complete success, while 9 (4.3 per cent) were dissatisfied. Five of the latter group cited frequent heartburn as the cause of their dissatisfaction. We conclude that abdominal pain, bloating and nausea occur as frequently in the general population as in patients following LC. Patients are more likely to suffer from heartburn and dysphagia following LC than a normal population supporting a link between cholecystectomy and lower oesophageal dysfunction.

Adult↗
PubMed1992

A study of change in age at first marriage and first fertility of Chinese women and population control.

The author examines the decline in Chinese women's "age at first marriage..., going on to analyze trends of development in women's average age at first marriage and changes in the interval before first fertility over the last few decades, and from there proposes an effective way to alleviate the population peak and control the population--gradually lengthening the interval before first fertility on the basis of maintaining the average age at first marriage." Data are from the 1982 census and other official sources.

Asia↗
PubMedDate not supplied

Population control.

Explore the source record for details and available documents.

Developing Countries↗
PubMed1994

Age, gender, and sensitivity to bleomycin-induced chromosome breakage in Down's syndrome and control populations.

The free radical theory of aging suggests that cells from individuals with premature aging syndromes, such as Down's syndrome, might be especially sensitive to radical-induced DNA damage. Although existing studies support this hypothesis, little work has been done on examining the impact of increasing age on radical sensitivity within the Down's syndrome population. Additionally, intercellular heterogeneity and gender differences in radical sensitivity have not been investigated. In this study, bleomycin-induced chromosome breakage was measured in lymphocytes from a population of adult men and women with Down's syndrome (age range 20-60 years) and a population of normal control men and women of the same age range. Change in breakage rates as a function of age and intercellular heterogeneity in breakage rates were examined in males and females of both groups. The findings are discussed in connection with longevity and cancer risk in the old male population.

Adult↗
PubMed1988

Measuring genetic change in a dairy herd using a control population.

A selection experiment was conducted to assess the change in production resulting from selection with artificial insemination using a randomly maintained control. The experiment continued for 16 yr with approximately 20 lactations in each of the two breeding groups annually. Selection and control production was compared using 1) intraseason herdmate comparisons (weighted) and 2) mixed model maximum likelihood estimates of year-season effects (adjusted). The regressions of differences in milk yield on years for the two approaches were 110 kg for milk (weighted) and 108 kg for milk (adjusted), corrected for inbreeding. The regressions for fat were 3.9 kg for fat (weighted) and 4.2 kg for fat (adjusted). These regression coefficients were 1.6 and 1.5% of the least squares means for milk (6987 kg) and fat (259 kg), respectively. Definitive trends were not evident for differences between the two groups in percent fat, percent SNF, days open, final type classification score, or heart girth. Even with the limited numbers in the closed control population, inbreeding, and nonrandomness in culling of females or in the choice of dams of bulls appeared to have little impact on control mean during the 16 yr.

Animals↗
PubMed1991

Use of the clonal assay for the measurement of frequencies of HPRT mutants in T-lymphocytes from five control populations.

The clonal assay was used to measure frequencies of 6-thioguanine-resistant (HPRT) T-lymphocytes in 111 donors from the following 5 control populations: 55 adult healthy volunteers; 20 untreated cancer patients; 8 healthy hospital workers serving as controls for 9 hospital workers sterilizing equipment with ethylene oxide; 15 factory workers serving as controls for 15 workers occupationally exposed to high doses of ethylene oxide; 13 pretreatment samples from donors undergoing a diagnostic test with Technetium-99m for an analysis of heart function. With respect to mutant frequency (MF), cloning efficiency (CE) and age distribution, the first 4 populations were identical. The Technetium group had significantly higher MFs and lower CEs but this can be attributed to the higher mean age of this group. Using the total data base, we calculated the following relationships between MF, CE, age and smoking: (1) ln MF = 4.23-0.63 x ln CE indicating that a doubling of the CE has the effect of decreasing the MF by 37%, (2) ln MF = 0.71 + 0.03 x age meaning that the MF increases by 3% from one year to the next, (3) ln CE = 4.87-0.04 X age indicating that the CE decreases by 0.98% from one year to the next, (4) ln MF = 3.25-0.52 x ln CE + 0.02 X age being the equation quantifying the interrelationship between MF, CE and age, (5) ln MF = 3.32-0.56 x ln CE + 0.01 x age + 0.31 s (where s = 1 for smokers and s = 0 for nonsmokers). Using the latter equation, which allows for effects of CE and age on the MF, a statistically significant effect of smoking could be established. For any combination of CE and age smoking has the effect of increasing the MF by 36%. The above conclusions and calculations remain essentially the same when donors with cloning efficiencies lower than 10 or 20% are excluded from the data base.

Adolescent↗
PubMed2000

Flow cytometric analysis of T lymphocyte subpopulations in large-bodied turkey lines and a randombred control population.

To investigate the effect of BW selection on immune cell populations of turkeys, T lymphocyte subpopulation analyses were conducted using peripheral blood from lines selected for increased BW and a randombred control population. The lines used included an experimental line (F) selected long-term for increased 16 wk BW, a randombred control line (RBC2) that served as the base population of the F line, and sire lines (A and B) from each of two major commercial turkey breeders. The peripheral blood lymphocytes were isolated and stained with mouse anti-chicken CD4 and CD8alpha antibodies in flow cytometric analysis. The polymorphism of CD8alpha in the F and A lines detected with the CT8 monoclonal antibody (mouse anti-chicken CD8alpha antibody) did not appear to be associated with BW and shank parameters. The present results showed that the F line had a significantly larger CD4+CD8- T cell subpopulation than did the RBC2 line at both ages, and this population proportion in the F line was also larger than that for one commercial sire line at 24 wk of age. There were no differences in other T cell subsets. The BW selection may have resulted in changes in T lymphocyte subpopulations and, therefore, may have affected disease resistance. The increased susceptibility to infectious diseases in the F line may be associated with the higher CD4+CD8- T cell subpopulation and the CD8alpha polymorphism.

Animal Husbandry↗
PubMed1984

Estimation of genetic trend in a selected population with and without the use of a control population.

Data from a selection experiment conducted with sheep at Massey University, New Zealand, were analyzed to obtain an evaluation of selection response. Selection was for heavy 14-mo greasy fleece weight. Approximately seven generations of selection were represented in the data. Three estimates of genetic superiority of the selected line to the control line were obtained. All three estimates were obtained from a mixed model evaluation using the individual animal model for predicting breeding values from own and relatives' records. The estimators were 1) deviation of selected line predicted yearly phenotypes from control line predicted yearly phenotypes, 2) deviation of the predicted yearly phenotype for the selected line from the year estimate in the control line and 3) the mean yearly breeding value from the analysis of the selected line only. The realized heritability using the first approach was .20. However, the control line was found to have a slight positive drift; hence, this estimate was biased downward. Using Approach 2, accounting for drift, the realized heritability was .23. The same realized heritability, .23, was obtained from an analysis of the selected line ignoring the control (Approach 3), when a prior heritability of .30 was assumed for the mixed model evaluation. The estimate of genetic trend from predicted breeding values in the latter approach is, however, quite dependent on the assumed heritability.

Animals↗