[Erythrocyte and plasma magnesium of the American Indian population of the Interandean Corridor].
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Adult↗
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Results for “CONSTANS”
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[Comparative study of various biological parameters in amerindian populations living at high altitudes and then transplanted to low lands].
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Adaptation, Physiological↗
Bosentan as a rescue therapy in scleroderma refractory digital ulcers.
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Adult↗
Regional gray and white matter metabolite differences in subjects with AD, with subcortical ischemic vascular dementia, and elderly controls with 1H magnetic resonance spectroscopic imaging.
OBJECTIVE: To use 1H magnetic resonance spectroscopic imaging to study differences in neuron density (N-acetylaspartate [NAA]), membrane phospholipid metabolites (choline [Cho]), and creatine-containing metabolites (creatine plus phosphocreatine [Cr]) in subjects with Alzheimer's disease (AD), with subcortical ischemic vascular dementia (SIVD), and elderly controls. DESIGN: Cross-sectional, between groups. SETTING: A Veterans Affairs medical center and university memory clinic. PARTICIPANTS: Forty elderly subjects with AD (n = 14), with SIVD (n = 8), and elderly controls (n = 18). MAIN OUTCOME MEASURES: We used 1H magnetic resonance spectroscopic imaging to acquire spectra from a 80 x 100 x 17-mm volume superior to the lateral ventricles. Spectra were analyzed from voxels in anterior, medial, and posterior gray and white matter using nuclear magnetic resonance-1 and the results were compared between groups using repeated measures analysis of variance (ANOVA), Tukey's test, and individual Student's t tests. RESULTS: Using ANOVA, significantly lower levels of NAA/Cho and NAA/Cr and significantly higher levels of Cho/Cr were observed across both gray and white matter voxels in subjects with AD. Using individual Student's t tests, a significantly lower level of NAA/Cho and a higher level of Cho/Cr were observed in the posterior gray matter in subjects with AD. Using ANOVA in subjects with SIVD, significantly lower gray and white matter NAA/Cr levels were observed. Using Tukey's test, the NAA/Cr level was significantly lower in frontal white matter voxels in subjects with SIVD compared with controls. CONCLUSIONS: Our findings in subjects with AD suggest neuron loss in gray matter, axon loss in white matter, and altered Cho metabolism in posterior brain regions. Our findings in subjects with SIVD are consistent with higher levels of creatine-containing metabolites and/or lower levels of NAA in frontal white matter.
Aged↗
Long-term mutagenicity studies with chloroform and dimethylnitrosamine in female lacI transgenic B6C3F1 mice.
The weight of evidence indicates that chloroform induces cancer in the female B6C3F1 mouse liver via a nongenotoxic-cytotoxic mode of action. However, it is probable that DNA damage occurs secondary to events associated with cytolethality and regenerative cell proliferation. The purpose of the present study was to evaluate the potential mutagenic activity of chloroform in the B6C3F1 lacI transgenic mouse liver mutagenesis assay including mutagenic events that might occur secondary to cytolethality. The positive control, dimethylnitrosamine (DMN) is a DNA-reactive mutagen and carcinogen. DMN-induced mutations were anticipated to require only a brief exposure and without further treatment were predicted to remain unchanged over time at those frequencies. Chloroform-induced mutations secondary to toxicity were anticipated to require longer exposure periods and to occur only under conditions that produced sustained cytolethality and regenerative cell proliferation. Female B6C3F1 lacI transgenic mice were treated with daily doses of 2, 4, or 8 mg/kg of DMN by gavage for 4 days and then held until analysis 10, 30, 90, and 180 days postexposure. Livers from DMN-treated mice exhibited a dose-related 2- to 5-fold increase over control mutant frequencies and remained at those levels for 10 through 180 days postexposure. Thus, following the initial induction by DMN no selective mutation amplification or loss was seen for this extended period of time. Female B6C3F1 lacI mice were exposed daily for 6 hr/day 7 days/week to 0, 10, 30, or 90 ppm chloroform by inhalation, representing nonhepatotoxic, borderline, or overtly hepatotoxic chloroform exposures. Timepoints for determination of lacI mutant frequency were 10, 30, 90, and 180 days of exposure. No increase in lacI mutant frequency in the liver was observed at any dose or timepoint with chloroform, indicating a lack of DNA reactivity. DNA alterations secondary to toxicity either did not occur or were of a type not detectable by lacI mutant frequency analysis, such as large deletions.
Administration, Inhalation↗
MRI geometric distortion: a simple approach to correcting the effects of non-linear gradient fields.
We present a method to correct intensity variations and voxel shifts caused by non-linear gradient fields in magnetic resonance images. The principal sources of distortion are briefly discussed, as well as the methods of correction currently in use. The implication of the gradient field non-linearities on the signal equations are described in a detailed way for the case of two- and three-dimensional Fourier imaging. A model of these non-linearities, derived from the geometry of the gradient coils, is proposed and then applied in post-processing to correct any images regardless of the acquisition sequence. Initial position errors, as large as 4 mm (i.e., four voxels of 1 x 1 x 1.4 mm3) before correction, are reduced to less than the voxel sizes after correction.
Humans↗
Sites of primary malignancies in patients presenting with cerebral metastases. A review of 120 cases.
A retrospective study is reported of 120 consecutive cases of patients presenting with brain metastases as the primary sign of their malignancy. Primary site was found in 62 patients (53 while alive and 9 at postmortem examination) and remained unknown in 58. Lung was the most frequent primary site (45% of known sites), and digestive malignancies were surprisingly the second most frequent primary site (19% of known sites), whereas breast was found in less than 5%. When primary site was disclosed, in 85% it was after history, clinical exam, chest x-ray, and pathologic findings. Survival was almost identical in both known and unknown primary sites: 54% versus 44% at 6 months, 20% versus 16% at 1 year, and 6% versus 5% at 2 years. It was concluded that extensive evaluations to identify primary sites do not appear to be rational in patients presenting with brain metastases.
Adolescent↗
Gc (vitamin D binding protein) subtype polymorphism and variants distribution among Saharan, Middle East, and African populations.
This article presents the results obtained by electrophoretic analysis of the group specific component polymorphism in more than 1,250 serum samples from populations living in the Sahara, the Middle East, and equatorial Africa. In addition to the alleles Gc1F and Gc1s, five variants, including one previously unknown, were found. The distribution of the alleles herein described permits speculation on exchanges and relations among the groups considered. The lowest frequencies of the gene Gc2 correspond to regions where sunlight is stronger. There is also a north-south gradient in the Gc1F gene frequency. This seems to parallel the gradient seen in skin pigmentation.
Africa, Northern↗
Population distribution of the human vitamin D binding protein: anthropological considerations.
The polymorphism of the serum vitamin D binding protein (DBP) in humans is based on the existence of three common alleles, Gc1F, Gc1S, and Gc2, and 84 rare alleles. The geographical distribution of Gc1F, Gc1S, and Gc2 alleles shows north to south clines, together with a balanced equilibrium between the Gc1F or Gc1S allele frequency and the Gc2 frequency. The distribution of the FST values shows high variability within a geographical area. For European and North Asiatic groups, the FST values are the lowest observed, and the reason may be a long process of homogenization. Aboriginal populations from Australia and New Guinea and groups from both North Africa and South America show the greatest heterogeneity of their allele frequencies. Systematic factors such as genetic drift and selection may account for this distribution. In contrast with the three main DBP alleles, the distribution of the rare alleles corresponds to patterns of human migrations that occurred during prehistoric and historic periods. Thus, the rare mutants are of particular relevance to anthropological and genetical investigations.
Alleles↗
Gene flow across tribal barriers and its effect among the Amazonian Içana river Indians.
Demographic information was obtained from 622 individuals of five communities of primarily Baniwa Amerindians living near the Içana river in Brazil. Four of these populations, plus another from the same area, were also studied genetically. The latter investigation included the blood and, in some cases, saliva of 531 subjects, variously tested in relation to 40 genetic systems. Demographically these groups are characterized by young age, high intertribal admixture, low non-Indian admixture, high exogamy but low marital distance and high inbreeding, high fertility but low variance in offspring number, and relatively low mortality. Their gene pool shows a peptidase B variant (PEPB2BAN1) and "private" polymorphism of carbonic anhydrase2 (CA2BAN1) until now observed only among them. Other distinctive characteristics are the low frequencies of LNS (0.08), LNs (0.09), RZ (0.01), RO or r(0.02), ACPA (0.08), GALTD (0.01), and the relatively high prevalences of Gm (0.05) and Gc1 (0.82). TfDchi occurs with a low prevalence (0.01). Genetic distance analysis reveals that the one Baniwa sample by history comprised of minimally admixed individuals is quite similar genetically to the Wapishana, another Arawak-speaking tribe some 900 km to the east, and that the genetic distances between the Baniwa communities reflect the amount of historical admixture in a way that indicates which should be excluded from considerations of intertribal genetic distances. Finally, the genetic relation of the Baniwa to the nearby tribes is examined.
Adolescent↗
Polymorphism of the vitamin D binding protein (DBP) among primates: an evolutionary analysis.
The distribution of the DBP (vitamin D binding protein) polymorphism is now well characterized among human populations but for primates only limited results are known. The aim of this paper is to describe the electrophoretic polymorphism of this protein among various species. Using three different electrophoretic methods, we are able to detect an unknown polymorphism and to classify the different alleles observed. These results may be used to set an international nomenclature for further comparisons. The different electrophoretic mobilities between Old and New World Monkeys show that: 1) the Cercopithecoïdea are presenting the largest genetic heterogeneity; 2) the DBP among the Galago corresponds to the lowest isoelectric points observed among Primates; 3) during the evolution from nonhuman Primates to Man, the DBP is able to keep its affinity for vitamin D derivatives despite the occurrence of significant molecular modifications; 4) among Anthropoïdea, the electrophoretic patterns of DBP are very close to the human Gc1 proteins. These results show that evolution at the DBP level can be considered as a continuous mechanism of structural modifications. A significant transition occurs during the differentiation between Cercopithecoïdea and Anthropoïdea. It is not too speculative to consider that some electrophoretic forms detected among Gorilla, Pongo, or Pan may be identical to rare variants observed among humans.
Animals↗
Gm haplotype distribution in Amerindians: relationship with geography and language.
A review is made of the Gm haplotype distribution in 60 groups of Eskimos, North, Central and South American Indians, totaling 22,808 individuals. Differences were observed in the shapes of the distribution of Gm*ag and the other markers. Nearly identical values for FST and average heterozygosities were obtained in the North+Central/South comparisons. North-South and Southwest/Northeast clinal differences were observed in the Americas using correspondence factorial analysis. The two haplotypes mainly responsible for these differences are Gm*axg and Gm*abOst. When the populations are classified by language groups, besides the recognized differences between Eskimos and Athabaskan (Na-Dene) speakers compared with Amerinds, others are found. For instance, Uto-Aztecan speakers of the United States and Mexico differ in Gm frequencies from the Nuclear Chibchan, Macro-Arawak, and Carib speakers of Central and South America. The notion of a homogeneous Amerind genetic pool does not conform with these and other results.
Computers↗
Axonal injury and membrane alterations in Alzheimer's disease suggested by in vivo proton magnetic resonance spectroscopic imaging.
We used spin-echo magnetic resonance imaging and proton magnetic resonance spectroscopic imaging in 8 patients with probable Alzheimer's disease and in 10 age-matched elderly control subjects to assess the effects of Alzheimer's disease on the brain. On magnetic resonance images the patients showed significant ventricular enlargements relative to the control subjects. We measured the distribution and relative signal intensities of N-acetylaspartate (a putative neuronal marker), of choline residues representing lipid metabolites, and of creatine-containing metabolites in a large section of the centrum semiovale containing white and mesial gray matter. Throughout the white matter of the patients with Alzheimer's disease compared to elderly control subjects, N-acetylaspartate was decreased relative to choline (N-acetylaspartate-choline ratio) and creatine-containing metabolites (N-acetylaspartate-creatine ratio) with no changes in the choline-creatine ratio. The N-acetylaspartate-choline ratio was lower and choline-creatine higher in the mesial gray matter of AD patients relative to elderly controls. The posterior section of the centrum semiovale in the patients showed increased choline-creatine and choline-N-acetylaspartate ratios with the N-acetylaspartate-creatine ratio unchanged between the patients and control subjects. These spectroscopic findings give suggestive evidence of diffuse axonal injury and membrane alterations in gray and white matter of the centrum semiovale in patients with Alzheimer's disease.
Aged↗
Relations between fatigue, neuropsychological functioning, and physical activity after treatment for breast carcinoma: daily self-report and objective behavior.
BACKGROUND: Previous research indicates that disease free breast carcinoma survivors who experienced severe fatigue also had many problems with regard to neuropsychological functioning and physical activity, measured with general self-report questionnaires. Both neuropsychological functioning and physical activity can be measured with daily self-report measures in addition to measures of objective behavior. The main objective of this study was to examine the relations between 1) fatigue and 2) daily self-reported and objective measures of neuropsychological functioning and physical activity. METHODS: Disease free breast carcinoma survivors and age-matched women with no history of breast carcinoma filled out a daily self-observation list and wore an actometer during a period of 12 days. Furthermore, they performed two standardized tests to assess neuropsychological functioning. RESULTS: No differences were found between severely fatigued disease free breast carcinoma survivors, nonseverely fatigued disease free breast carcinoma survivors, and women in a control group with regard to daily self-reported and objective physical activity. The severely fatigued disease free patients reported more impairment in neuropsychological functioning on daily questionnaires compared with nonseverely fatigued disease free patients and women in the control group. However, no differences were found between these three groups on a standardized concentration task. On a standardized reaction time task, no significant differences were found between the two groups of disease free breast carcinoma survivors: However, women in the severely fatigued group had a significantly longer reaction time compared with women in the control group. CONCLUSIONS: Fatigue is correlated strongly with daily self-reported neuropsychological functioning, but not with objective neuropsychological functioning, in a laboratory setting. In the current study, fatigue was not correlated with daily self-reported and objective physical activity.
Activities of Daily Living↗
The group specific component/vitamin D binding protein (GC/DBP) system in the analysis of disputed paternities.
The group-specific component (GC) was discovered in 1959, and in the same year a vitamin D binding protein (DBP) in human plasma was found; however, their identity was established as late as 1975. In the GC/DBP system three common alleles, GC*1F, GC*1S, and GC*2, determine six GC phenotypes: 1F, 1S, 2, 1F-1S, 2-1F and 2-1S, these common alleles having been found in all human populations studied. In addition, more than 120 GC variants have been discovered, with varying frequencies in different populations. The distribution of the common GC phenotypes and the presence of rare GC variant phenotypes render the GC/DBP system useful for the analysis of disputed paternities.
Biomarkers↗
Identification of group specific component/vitamin D-binding protein (GC/DBP) mutants by isoelectric focusing in immobilized pH gradients.
The six common genetic types of the group specific component/vitamin D-binding protein (GC/DBP) system are usually classified by isoelectric focusing in carrier ampholytes, followed by visualization of the GC proteins by immunoprinting with monospecific antiserum. In addition, more than 120 mutant GC types have been discovered. For their identification additional methods were necessary, including polyacrylamide gel electrophoresis, isoelectric focusing in the presence of 3 M urea as well as isoelectric focusing in immobilized pH gradients. The application of the last method is described in detail and several examples of GC/DBP mutants identified thereby are presented.
Gels↗
[Delayed hypersensitivity reactions in patients bearing malignant brain tumors with human tumor cell lines grown in vitro].
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Antigens↗
Linear scaling approaches to quantum macromolecular similarity: evaluating the similarity function.
The evaluation of the electron density based similarity function scales quadratically with respect to the size of the molecules for simplified, atomic shell densities. Due to the exponential decay of the function's atom-atom terms most interatomic contributions are numerically negligible on large systems. An improved algorithm for the evaluation of the Quantum Molecular Similarity function is presented. This procedure identifies all non-negligible terms without computing unnecessary interatomic squared distances, thus effectively turning to linear scaling the similarity evaluation. Presented also is a minimalist dynamic electron density model. Approximate, single shell densities together with the proposed algorithm facilitate fast electron density based alignments on macromolecules.
Hemoglobins↗