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PubMed1987

Illiteracy and brain damage--1. Aphasia testing in culturally contrasted populations (control subjects).

One hundred neurologically healthy adults were tested for their pointing (choosing one of four or six line drawings as the match to an auditorily presented linguistic stimulus), naming (from line drawings), and repetition abilities. All subjects were unilingual adult right-handers. Fifty-seven subjects were totally unschooled illiterates and 43 were fluent readers. Statistically significant differences were found to exist between the scores of the illiterate and literate subpopulations across all tasks. With the focus being placed on these cultural differences, the discussion bears on: (a) the interaction between linguistic and iconographic factors in certain types of naming and pointing tasks currently used in clinical and research aphasiology, (b) some of the linguistic parameters which are apparently at stake in repetition behavior, and (c) the circumstances in which aphasiological research dealing with groups of patients cannot yield reliable data without reference to neurologically healthy controls. It is argued that, when testing brain-damaged patients of different cultural backgrounds, one runs the risk of over- or underestimating the frequency of aphasia if one does not refer to norms which explicitly take educational level into account.

Adult↗
PubMedDate not supplied

On the frequency of chromosome exchanges in a control population measured by chromosome painting.

Chromosome painting has been shown to be a valid and rapid method for quantifying structural chromosome rearrangements in human lymphocytes. The method is particularly useful for detecting stable aberrations which are difficult and expensive to quantify with classical methods. The inherent stability of translocations has enabled them to be used as a biodosimeter for chronic and temporally displaced exposure to radiation. Translocations may also be useful for quantifying chronic exposure to other environmental agents which may result in an accumulation of cytogenetic damage with age. Most exposures are chronic and occur at low rates, and conventional cytogenetic methods such as dicentric analysis are not expected to be informative. To understand the extent to which age and lifestyle factors impact the frequency of stable aberrations, we have performed chromosome painting on metaphase-arrested lymphocytes cultured from 47 healthy adults ranging in age from 19 to 77 years, and from umbilical cord blood obtained from eight healthy full-term infants. All subjects had previously been screened to eliminate those who had received significant occupational or accidental exposure to radiation or chemicals, and none had received chemo- or radiotherapy. Due to the infrequent occurrence of stable aberrations in peripheral lymphocytes, we analyzed the equivalent of more than 1100 metaphase cells from each of these 55 people. An average of one cell in 130 (0.77%) was observed to have a translocation or a stable insertion. A significant relationship between stable aberrations and the square of the age is apparent (R2 = 0.69, Y = 0.0615 + 0.000304 age2; p < 0.00001). These results support the hypothesis that stable aberrations accumulate with time, and are likely to integrate adverse environmental exposure.

Adult↗
PubMed1995

SCE analysis in human lymphocytes of a Spanish control population.

SCE (sister-chromatid exchanges), HFC (high frequency cells) and PRI (proliferative rate index) were studied in the peripheral blood lymphocytes of 154 healthy male volunteers, from Barcelona (Spain). SCE, HFC and PRI variability between and/or within individuals was estimated by means of a mixed linear model. This model allows a determination of the relationship between confounding factors (demographics, life style, work exposure and medical history) and the cytogenetic and cytokinetic parameters analyzed. The results obtained indicate the existence of an important intra-individual heterogeneity in SCE rates, as well as in HFC and PRI values. Although age did not seem to affect either the SCE frequency or the HFC percentage, it showed a significant positive association with the presence of cells with higher SCE frequencies. With respect to the confounding factors, only cigarette smoking increased the SCE rates and the HFC values. On the other hand, PRI mean showed significant differences dependent on age and was inversely correlated with alcohol consumption and X-ray exposure.

Adult↗
PubMed1993

HTLV-1 antibody class and subclass distribution in African TSP and control populations.

The humoral immune responses in 44 sera from HTLV-1 seropositive African subjects were compared. The sample population was composed of 12 patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), 12 patients with other neurological conditions and 20 asymptomatic carriers. Samples HTLV-1 antigens were tested against all immunoglobulin classes and IgG subclasses, using the Western blot technique with polyclonal and monoclonal antibodies. Whilst IgG reacted with gag, env and tax products for the three groups studied, IgM and IgA were found to react more frequently with HTLV-1 in HAM/TSP patients. For these patients, IgM and IgA were particularly directed against tax and env proteins. Among IgG subclasses, IgG1 was most sensitive to gag, env and tax products reacting in similar proportions in all three groups. IgG2 and IgG4 were apparently not involved. IgG3 was most responsive in HAM/TSP patients. These data are similar to those observed in AIDS patients, LAS and HIV asymptomatic carriers and emphasize the role of HTLV-1 in HAM/TSP.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Reaction time of the Continuous Performance Test is an endophenotypic marker for schizophrenia: a study of first-episode neuroleptic-naive schizophrenia, their non-psychotic first-degree relatives and healthy population controls.

Sustained attention has been proposed as an endophenotype of schizophrenia, and consequently may be useful as a quantitative trait in genetic studies. In the present study, we used the continuous performance test (CPT) to measure sustained attention in 112 first-episode and neuroleptic-naive schizophrenic patients, 296 of their non-psychotic first-degree relatives, and 452 normal controls. Compared with controls, probands with schizophrenia showed worse performance on all measures of CPT. Parents, siblings and offspring of probands were also impaired on 'hit reaction time', an index of psychomotor processing speed of the correct response. Hit reaction time was also independent of the acute clinical features of the disease, indicating it is a trait rather than a state marker. Our findings supported the use of the hit reaction time measure of the CPT as an endophenotype marker for schizophrenia.

Adolescent↗
PubMed1980

Comparison of endothelial cell density in diabetics and a control population.

We compared the endothelial cell density of 96 corneas from 52 diabetics with proliferative diabetic retinopathy with 61 corneas from 32 normal subjects by specular microscopy. Although the regression curve of the diabetic group was steeper, we found no statistically significant difference in endothelial cell density between the two groups.

Adolescent↗
PubMed2003

The prevalence of atrial fibrillation in incident stroke cases and matched population controls in Rochester, Minnesota: changes over three decades.

OBJECTIVES: We sought evidence of a change in the prevalence of atrial fibrillation (AF) over a 30-year period among residents of Rochester, Minnesota. BACKGROUND: Atrial fibrillation is increasingly encountered in clinical practice, but there is limited data on secular trends of AF over time. METHODS: Within a longitudinal case-control study of ischemic stroke, the prevalence of AF and of selected comorbid conditions among incident stroke cases and age- and gender-matched controls between 1960 and 1989 was determined. RESULTS: The mean age +/- standard deviation for the 1,871 stroke cases (45% men) and matched controls was 75 +/- 11 years. For cases, age-adjusted estimates of AF prevalence for 1960 to 1969, 1970 to 1979, and 1980 to 1989 were 11%, 13%, and 16%, respectively, for men, and 13%, 16%, and 20% for women. For controls, the rates were 5%, 8%, and 12%, respectively, for men, and 4%, 6%, and 8% for women. Increasing AF prevalence was associated with increasing age (doubling of odds per decade of age in both cases and controls) and calendar time adjusted for age and gender (cases: odds ratio [OR] per 5 years 1.13, 95% confidence interval [CI], 1.05 to 1.22; controls: OR per 5 years 1.24, 95% CI 1.12 to 1.37). The rates of increase with calendar time were significant for cases (p = 0.001) and controls (p < 0.001) and comparable between the genders. CONCLUSIONS: The prevalence of AF increased significantly in ischemic stroke patients and their controls from 1960 to 1989 in Rochester, Minnesota, independent of age and gender. The rate of increase did not differ significantly between men and women.

Aged↗
PubMed2002

Evolutionary dynamics and population control during in vitro selection and amplification with multiple targets.

Iterative cycles of in vitro selection and amplification allow rare functional nucleic acid molecules, aptamers, to be isolated from large sequence pools. Here we present an analysis of the progression of a selection experiment that simultaneously yielded two families of RNA aptamers against two disparate targets: the intended target protein (B52/SRp55) and the partitioning matrix. We tracked the sequence abundance and binding activity to reveal the enrichment of the aptamers through successive generations of selected pools. The two aptamer families showed distinct trajectories of evolution, as did members within a single family. We also developed a method to control the relative abundance of an aptamer family in selected pools. This method, involving specific ribonuclease digestion, can be used to reduce the background selection for aptamers that bind the matrix. Additionally, it can be used to isolate a full spectrum of aptamers in a sequential and exhaustive manner for all the different targets in a mixture.

Base Sequence↗
PubMed1997

Population control of microglia: does apoptosis play a role?

Brain lesions, even of the most subtle type, are accompanied by the activation of microglia, the main immune cells of the brain. Microglial cells dramatically increase in number through proliferation and adhere to the injured neurons, where they displace the synaptic input. After proliferation, microglia gradually migrate into the nearby parenchyma and appear to decrease in number. Here we examined the possible involvement of apoptosis in the regulation of the microglial cell number using Terminal transferase mediated d-UTP Nick End-Labelling (TUNEL). In vitro, cell death is a common phenomenon in microglial cell cultures, and is enhanced by the withdrawal of the mitogen, granulocyte-macrophage colony stimulating factor. In vivo, application of the TUNEL-reaction revealed TUNEL-positive microglia beginning at day 4, with a peak 7 days after transection of the facial nerve. Surprisingly, TUNEL-labelling in vivo was localized on the outer side of the nuclear membrane and in the microglial cytoplasm, with very little staining within the nucleus itself. These TUNEL-labelled cells also lacked other classic morphological signs of apoptosis, like membrane blebbing, chromatin condensation and apoptotic bodies. These data suggest that the regulation of post-mitotic microglia is not mediated by the classic pathway of apoptosis.

Animals↗
PubMed1990

Hormone levels in older women: a study of post-menopausal breast cancer patients and healthy population controls.

Hormone concentrations in blood and total 12 h urine values were compared between 40 post-menopausal women with breast cancer and 40 control women in a study which carefully controlled for the possible confounding effects of age, weight and pregnancy history by individually matching cases and controls on these factors. Breast cancer cases had received only surgical treatment for their localised disease, which was diagnosed from 1 to 9 years before hormonal evaluation. Cases had 15% higher serum oestradiol levels (P = 0.02), 40% more urinary oestradiol (P = 0.03) and 44% more urinary oestriol (P = 0.04) than control women. Cases also had higher levels of serum and urinary oestrone, but these differences were not statistically significant. The percentages of serum oestradiol not bound to albumin or sex-hormone binding globulin did not differ between cases and controls, nor were there statistically significant differences in the serum levels of prolactin, sex-hormone binding globulin or dehydroepiandrosterone sulphate. These results provide further support for the hypothesis that breast cancer risk is determined in part by post-menopausal serum oestrogen concentration.

Aged↗
PubMed1996

Low prevalence of hepatitis C infection in hepatocellular carcinoma (HCC) cases and population controls in Guangxi, a hyperendemic region for HCC in the People's Republic of China.

Southern Guangxi, China has one of the highest incidences of hepatocellular carcinoma (HCC) in the world. Serum samples collected from subjects of an earlier case-control study (39 cases, 41 controls) and from a random sampling of a residential male cohort (n = 100) were tested for antibodies for the hepatitis C virus (anti-HCV) using ELISA version 2.0 with confirmation by RIBA version 2.0. Only one of 141 (0.7%, upper 95% confidence limit, 3.2%) control subjects and none of 39 (upper 95% confidence limit, 6.07%) HCC cases tested positive for anti-HCV. Our results indicate that hepatitis C infection is not an important environmental determinant of HCC risk in this hyperendemic region.

Adult↗
PubMed2002

Relationship between bleeding time test and postextraction bleeding in a healthy control population.

OBJECTIVE: We sought to determine whether cutaneous bleeding time (BT) is related to bleeding outcome measures after a single tooth extraction. STUDY DESIGN: This was a prospective clinical pilot study of 30 subjects. Cutaneous BT was evaluated before a single tooth extraction. After extraction, an oral BT was determined. Subjects were contacted 3 to 7 hours and 2 days after extraction to assess further postoperative bleeding. RESULTS: The mean cutaneous BT was 5.9 minutes (range 1.5-10.0 minutes). The mean oral BT was 7.5 minutes (range 0-20 minutes). Cutaneous BT did not correlate with oral BT or any of our measures of postoperative bleeding. However, the oral BT correlated with the number of hours of bleeding after surgery (R(s) = 0.54, P =.03). The time necessary to perform the extraction correlated with the extraction site bleeding 3 to 7 hours after surgery (R(s) = 0.67, P =.0006). CONCLUSION: Cutaneous BT did not correlate with measures of postoperative bleeding in the present study, but oral BT immediately after extraction correlated with the duration of subsequent postoperative bleeding.

Adult↗