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Results for “adaptive sampling”

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PubMed1996

Cognitive test performance in a community-based nondemented elderly sample in rural India: the Indo-U.S. Cross-National Dementia Epidemiology Study.

Interpretation of cognitive test performance among individuals from a given population requires an understanding of cognitive norms in that population. Little is known about normative test performance among elderly illiterate non-English-speaking individuals. An age-stratified random sample of men and women, aged 55 years and older, was drawn from a community-based population in the rural area of Ballabgarh in northern India. These Hindi-speaking individuals had little or no education and were largely illiterate. A battery of neuropsychological tests, specially adapted from the CERAD neuropsychological battery, which was administered to this sample, is described. Subjects also underwent a protocol diagnostic examination for dementia. Norms for test performance of 374 nondemented subjects on these tests are reported across the sample and also by age, gender, and literacy.

Aged↗
PubMed2001

Application of the comet and micronucleus assays to butterfish (Pholis gunnellus) erythrocytes from the Firth of Forth, Scotland.

This report describes an investigation of genotoxic effects in an inter-tidal fish species sampled along a pollution gradient in the Firth of Forth, Scotland, UK. The comet assay is an electrophoretic technique for measuring DNA breakage in nuclei from individual cells and has only recently been applied to field investigations of genotoxicity. The measurement of nuclear anomalies (NA), such as the presence of micronuclei (MN) and 'lobes', has been successfully utilised in many field studies of genotoxic effects of contaminated sediments. These two techniques were applied to nucleated red blood cells (RBC) from the butterfish, Pholis gunnellus. The comet assay was adapted and validated for use in this species. Fish were sampled from the inner Firth of Forth, which has a legacy of industrial contamination and the outer Firth of Forth which is comparatively clean. The analysis of DNA strand breakage using this technique did not reveal any significant differences between animals sampled from inner and outer zones of the Firth. In contrast, MN and NA frequencies were elevated in the inner polluted zone of the Firth compared to the outer zone. This study suggests: (1) there are genotoxic effects associated with contaminants in the inner Firth of Forth, and (2) the comet assay may not be a suitable genotoxicity biomarker in fish.

Animals↗
PubMed1999

Cognitive adaptation: a women's health perspective for reducing stress during childbearing.

The purpose of this study is to evaluate psychological changes in women of three minority ethnic groups in a program of psychosocial services that promoted positive cognitive adaptation to childbearing throughout pregnancy and the postpartum period. In this prospective longitudinal study, both cognitive adaptation and generalized stress were measured at each trimester of pregnancy as well as after birth and 3 months postpartum. The mean scores at each time are first compared with first trimester scores for women in the program and then with scores for comparable women in a cross-sectional sample tested before the program. For women in the program, results of the psychological adaptation measures and the stress measures had improved from their first trimester value by the time of birth. Stress levels of women in the program were less than for women in the corresponding comparison sample from the third trimester on. Enhanced perinatal services that include interventions and monitoring strategies aimed at improving the cognitive adaptation of women to childbearing are important in promoting stress reduction in women and infants.

Adaptation, Psychological↗
PubMed2000

Tendon tissue sampling.

Mechanical load is regarded as the most important etiologic factor in cumulative trauma disorders affecting human tendons. At present there is limited knowledge concerning adaptation and the influence of training on human tendon tissue and the time process of developing a chronic tendon disorder. Tendon tissue samples and data concerning tendon pathology and repair have been derived from biopsies removed during surgery for rupture or pain conditions and from autopsy material. The ultrasound-guided percutaneous core biopsy technique provides the possibility to obtain tendon tissue from human Achilles and patellar tendon with limited discomfort for the individual. The specimens can be used for diagnostic purposes or for research and have the potential to highlight novel knowledge in, for example, the early stages of painful human tendon disorders. The fact that the procedure is invasive is a limitation. Autopsy material has limitations regarding poor information on case history, post mortem alterations and legal regulations on the use of tissue for medical purposes. The inflammatory process quickly affects ruptured tendons. The subcutaneous tendons that sustain a rupture are commonly characterized by degenerative alterations. Many tendon ruptures are treated with surgery, facilitating easy access to biopsy material. In summary, tendon tissue sampling in humans has obvious limitations. The recently described use of the core biopsy technique in human tendon research and diagnosis gives potential for new knowledge concerning human tendon adaptation, repair and disease.

Achilles Tendon↗
PubMed2005

Capacity limitations and the detection of correlations: comment on Kareev (2000).

Y. Kareev (2000) argued that the limited capacity of working memory may be an adaptive advantage for the early detection of useful correlations. His analysis indeed suggests that the optimal sample size is close to G. A. Miller's (1956) "magical number 7 +/- 2." The authors point out logical and statistical limitations of Y. Kareev's (2000) analysis, including that it neglects that the adaptive value is not determined by the hit rate but by the posterior probability of hit and that only signal trials are considered. The authors' analysis demonstrates that when these limitations are corrected for, the alleged benefit for small samples does not occur, and larger samples imply considerable improvement in the detection of correlations.

Adaptation, Psychological↗
PubMed2002

The longitudinal relationship between drug use and risky sexual behaviors among colombian adolescents.

OBJECTIVE: To identify the longitudinal relationships between drug use and risky sexual behaviors and early pregnancy in Colombian adolescents. DESIGN: Confidential survey of adolescents, consisting of structured individual interviews, at 2 time points, 2 years apart. A standard self-report questionnaire was adapted to ensure linguistic and cultural relevance. SETTING: Community samples representing differing levels of risky sexual behavior and drug use. Cohorts were drawn from higher- and lower-risk geographic areas and from various self-reported ethnic groups. PARTICIPANTS: Adolescents (N = 2226) randomly selected from 3 major Colombian cities: Bogotá, Medellín, and Barranquilla. MAIN OUTCOME MEASURES: Data were collected concerning adolescent drug use, sexual behaviors, and a history of pregnancy. The youths' drug use included measures of all illegal drugs. RESULTS: By using regression analyses (controlling for demographic variables) a reciprocal longitudinal relationship between risky sexual behaviors and drug use was identified. Those adolescents who reported higher levels of drug use at time 1 also had more sexual partners, had higher frequencies of unprotected sex, and were more likely to have experienced early pregnancy at time 2. The reverse relationship was true as well. The level of violence experienced by the adolescent emerged as a moderator of some of these relationships. CONCLUSIONS: Reducing adolescent drug use may also reduce levels of risky sexual behavior and early pregnancy and vice versa. Furthermore, the importance of addressing violence as a risk factor for both problem behaviors is emphasized.

Adolescent↗
PubMed1997

Reverse transcription-polymerase chain reaction-based methodology to quantify differential gene expression directly from microdissected regions of frozen tissue sections.

Quantitative differences in the expression of oncogenes are a critical feature of the cancer process. Several methods are currently available for assessing differential gene expression, but none can be used to determine quantitative changes in gene expression from small numbers of cells. The ability to conduct this type of quantitative analysis would be useful in the study of definable, early stages of carcinogenesis when very few cells are involved. We therefore developed a highly sensitive, slide-based technique that incorporates the benefits of in situ polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR) to quantify differential c-myc gene expression from liver tissue sections having either low or high levels of proliferating hepatocytes. To eliminate the need for isolating and quantifying mRNA, cells of interest were microdissected from frozen histological sections and their RNA directly subjected to RT-PCR amplification. These reactions were conducted in the presence of an internal RNA standard that was specifically designed to normalize differential RT and PCR efficiencies between samples. GENESCAN software analysis was used to determine the ratios of the RT-PCR products of the target gene to the RNA standard. These ratios were then normalized to the numbers of cells isolated, as quantified by image analysis, and comparative gene expression values were determined between sample groups. We conclude that this technology can be adapted to study any gene of interest in any type of frozen tissue or isolated cells. This methodology is particularly applicable to the molecular analysis of histopathologically distinct preneoplastic and neoplastic lesions identified on tissue sections.

Animals↗
PubMed1992

Evaluation of inductively coupled mass spectrometry for the determination of platinum in plasma.

Among the different analytical methods used for the determination of platinum in blood plasma from patients treated by platinum derivatives, inductively coupled plasma mass spectrometry appears to be the most sensitive (detection limit 0.05 microgram l-1) and the best adapted for measuring low concentrations. The preparation of the samples consisted only of a dilution. The recoveries were close to 100% and both within-run and between-days reproducibility were very good. The determination of free platinum which was only about 5% of total plasma platinum was chosen to illustrate the inductively coupled mass spectrometric method.

Cisplatin↗
PubMed1998

Identification of a gene unique to Mycobacterium avium subspecies paratuberculosis and application to diagnosis of paratuberculosis.

Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is the etiologic agent of paratuberculosis (Johne's disease), a chronic granulomatous enteritis in ruminants. Currently, there is a need for improved diagnostic tests because of the lack of methods for accurate, rapid and reliable detection of M. paratuberculosis infection. A M. paratuberculosis gene (hspX) was cloned, sequenced, and a 30 bp species-specific oligonucleotide was synthesized. As an internal control to identify mycobacterial strains, a 33 bp Mycobacterium genus-specific oligonucleotide was synthesized based on the conserved 5' terminus of the mycobacterial recA gene. Dioligonucleotide hybridization (dOH) analysis identified 28/28 (100%) mycobacterial strains and specifically identified 14/14 (100%) reference (ATCC 19698), bovine, ovine and human isolates of M. paratuberculosis. The M. paratuberculosis-specific oligonucleotide distinguished M. paratuberculosis isolates from related mycobacteria, including all closely related members of the Mycobacterium avium complex (MAC) tested in this study. The members of MAC tested in this study included Mycobacterium avium subspecies avium (M. paratuberculosis, Mycobacterium avium subspecies silvaticum (M. silvaticum) and Mycobacterium intracellulare strains. Hybridization was not observed with DNA extracted from a selected group of other bacterial pathogens. The experiments indicate that the dOH analysis is a useful diagnostic tool to detect mycobacterial infection, specifically M. paratuberculosis. The dOH method could be a good alternative to existing assays and will be adapted for specific identification of M. paratuberculosis from faecal samples, mixed bacteriologic cultures, tissue specimens and whole blood.

Amino Acid Sequence↗
PubMed1992

Coping processes as mediators of the relationship between hardiness and health.

Hardiness has been hypothesized to moderate the impact of stress on health by influencing coping responses, but little attention has been focused upon these associations. This study examined the relationship among hardiness, coping, and illness while attending to recent criticisms of the hardiness literature including the potential overlap with neuroticism, whether hardiness is a unitary construct, and the predominant use of male samples. Hardiness was found to be positively related to adaptive coping variables and negatively related to maladaptive coping variables. Problem-focused, support-seeking, and avoidant coping were found to mediate the hardiness-illness relationship. Although these hardiness-coping relationships were partially independent of the influence of neuroticism, the relationship of both coping and hardiness with self-reported illness appeared to result from the common influence of neuroticism. Consistent with previous research, the commitment and control components correlated most consistently with coping variables, and predicted hardiness effects were most consistently demonstrated for males.

Adaptation, Psychological↗
PubMed1996

A taxonomy of neurobehavioral functions applied to neuropsychological assessment after head injury.

Neuropsychological dysfunctions after traumatic brain injury are classified into a taxonomy to plan a comprehensive examination, and organize and report findings for diagnosis and treatment: consciousness, information processing, sensorimotor, neurophysiological, cerebral personality disorders, intelligence, memory, language, stress, psychodynamic, identity and weltanschauung, adaptation, complex adaptive functions, and development of children. Wide-range sampling enhances the detection of acute and late-developing dysfunctions, and diagnosis of complex syndromes. Historical, personality, and injury data are components of the assessment. Issues discussed include underestimation of brain injury, malingering, interaction of symptoms, symptom persistence, and noncerebral lesional contributors to impairment after mild head injury.

Brain Damage, Chronic↗
PubMed2006

Computerized adaptive testing of diabetes impact: a feasibility study of Hispanics and non-Hispanics in an active clinic population.

BACKGROUND: Diabetes is a leading cause of death and disability in the US and is twice as common among Hispanic Americans as non-Hispanics. The societal costs of diabetes provide an impetus for developing tools that can improve patient care and delay or prevent diabetes complications. METHODS: We implemented a feasibility study of a Computerized Adaptive Test (CAT) to measure diabetes impact using a sample of 103 English- and 97 Spanish-speaking patients (mean age = 56.5, 66.5% female) in a community medical center with a high proportion of minority patients (28% African-American). The 37 items of the Diabetes Impact Survey were translated using forward-backward translation and cognitive debriefing. Participants were randomized to receive either the full-length tool or the Diabetes-CAT first, in the patient's native language. RESULTS: The number of items and the amount of time to complete the survey for the CAT was reduced to one-sixth the amount for the full-length tool in both languages, across disease severity. Confirmatory Factor Analysis confirmed that the Diabetes Impact Survey is unidimensional. The Diabetes-CAT demonstrated acceptable internal consistency reliability, construct validity, and discriminant validity in the overall sample, although subgroup analyses suggested that the English sample data evidenced higher levels of reliability and validity than the Spanish sample and issues with discriminant validity in the Spanish sample. Differential Item Function analysis revealed differences in responses tendencies by language group in 3 of the 37 items. Participant interviews suggested that the Spanish-speaking patients generally preferred the paper survey to the computer-assisted tool, and were twice as likely to experience difficulties understanding the items. CONCLUSIONS: While the Diabetes-CAT demonstrated clear advantages in reducing respondent burden as compared to the full-length tool, simplifying the item bank will be necessary for enhancing the feasibility of the Diabetes-CAT for use with low literacy patients.

Adult↗
PubMed1994

Cytogenetic and growth factor gene analysis of a renal carcinoma cell line.

Although there are many studies analyzing cytogenetic or molecular alterations of human renal primary tumors, there have only been a few reports addressing both questions on renal cell carcinoma (RCC) cell lines. We have therefore investigated an RCC cell line, namely KTCTL-26A, by banding techniques and simultaneous growth factor gene expression analysis. KTCTL-26A represents a well-defined stemline and sidelines in the near-diploid range with clonal aberrations involving chromosomes 2, 3, 5, 7, 9, 13, 16, 21, 22, and Y in structure and/or number. The predominant karyotypic changes were a partial loss of chromosome 3p (ie, 3p14) and a gain of copies of chromosome 7 (trisomy or partial tetrasomy). By Northern analysis, in KTCTL-26A we found underexpression of the proEGF-gene (located on chromosome 4) and overexpression of the genes for proTGF-alpha and the EGF-receptor, which are located on chromosomes 2 and 7, respectively. By Southern blot analyses there was no evidence for an amplification in the case of the EGF-R and proTGF-alpha genes. Because these changes of gene expression were observed in both the cell line and in primary kidney tumor samples, they seem to be of constitutive (and not adaptive) nature. Hence, KTCTL-26A can serve as a model for the study of the origin of these molecular alterations and as a preclinical model for their genetic manipulation (e.g., by using antisense-oligonucleotides) for therapeutic purposes.

Carcinoma, Renal Cell↗
PubMed1992

A novel, spectrophotometric microneutralization assay for respiratory syncytial virus.

We describe a simple and rapid microneutralization assay for respiratory syncytial virus (RSV) based on the colorimetric quantitation of the conversion of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to a formazan product by the mitochondria of viable cells. Conditions for RSV infectivity were first optimized for sensitivity and reproducibility based on cell density and on RSV concentration as a function of multiplicity of infection (MOI) and time post-infection and the resulting optical densities were shown to be inversely proportional to MOI. For RSV neutralization, dilutions of heat-inactivated human plasma were preincubated with RSV and complement prior to infection of cells in microtiter plates. Following MTT dye conversion, 50% RSV neutralization titers were determined by linear regression analysis of the optical density values and endpoints were markedly influenced by MOI. The MTT-based assay was shown to be comparably sensitive to the plaque reduction assay for quantitation of neutralizing antibody, but more readily adaptable to the screening of a large number of samples. Finally, we demonstrated that the MTT microneutralization assay for RSV was useful for quantitation assay of neutralization activity in sera of mice and cotton rats.

Adult↗
PubMed1992

Microanalytical high-performance liquid chromatographic assay for cefpirome in human milk and urine.

To permit the characterization of cefpirome disposition in lactating females, a previously published high-performance liquid chromatographic (HPLC) method for determining the drug in serum was adapted for use with milk and urine. This automated, microanalytical technique requires 50 microliters of biological matrix, which is subjected to an isopropanol extraction. Chromatography was accomplished using a microbore HPLC system, a reversed-phase C18 column and a mobile phase of 0.3% triethylamine in water (pH 5.1). Cefpirome and the internal standard (beta-hydroxypropyltheophylline) were monitored using UV detection at 240 nm and had retention times of 2.84 and 5.05 min, respectively. The method was linear up to 500 mg/l for both matrices and had a limit of detection of 0.6 mg/l. The interday variation (relative standard deviation) at concentrations of 5.0, 50.0 and 500.0 mg/l was consistently less than 5% in both urine and breast milk. The method was found to be free from interference by other commonly administered medications and readily adaptable for use in clinical investigations. The ease of sample preparation, small sample volume requirement, short chromatographic time, apparent lack of interferences, analytical sensitivity and high precision and accuracy make this method ideal for use in pharmacokinetic investigations involving the determination of cefpirome in human milk and urine.

Cephalosporins↗
PubMed2006

Accurate prediction of enzyme subfamily class using an adaptive fuzzy k-nearest neighbor method.

Amphiphilic pseudo-amino acid composition (Am-Pse-AAC) with extra sequence-order information is a useful feature for representing enzymes. This study first utilizes the k-nearest neighbor (k-NN) rule to analyze the distribution of enzymes in the Am-Pse-AAC feature space. This analysis indicates the distributions of multiple classes of enzymes are highly overlapped. To cope with the overlap problem, this study proposes an efficient non-parametric classifier for predicting enzyme subfamily class using an adaptive fuzzy r-nearest neighbor (AFK-NN) method, where k and a fuzzy strength parameter m are adaptively specified. The fuzzy membership values of a query sample Q are dynamically determined according to the position of Q and its weighted distances to the k nearest neighbors. Using the same enzymes of the oxidoreductases family for comparisons, the prediction accuracy of AFK-NN is 76.6%, which is better than those of Support Vector Machine (73.6%), the decision tree method C5.0 (75.4%) and the existing covariant-discriminate algorithm (70.6%) using a jackknife test. To evaluate the generalization ability of AFK-NN, the datasets for all six families of entirely sequenced enzymes are established from the newly updated SWISS-PROT and ENZYME database. The accuracy of AFK-NN on the new large-scale dataset of oxidoreductases family is 83.3%, and the mean accuracy of the six families is 92.1%.

Algorithms↗
PubMed2006

Proteomic analysis identifies candidate proteins associated with distant recurrences in breast cancer after adjuvant chemotherapy.

Breast cancer is a heterogeneous disease and it is of importance to select patients with regard to different prognosis and treatment sensitivity to individualize treatment regimes. In this study we successfully adapted a protein extraction protocol from mRNA extracted tumor samples enabling two-dimensional gel electrophoresis (2-DE) analysis of samples previously analyzed by cDNA microarray. The aim was to find candidate proteins that distinguish breast cancer patients with or without recurrences after adjuvant CMF (cyclophosphamide, methotrexate and 5-FU) treatment within four years to follow-up. We identified several proteins distinguishing the recurrence group from the non-recurrence group, especially in the ER and PgR positive subgroup (n=7). The induced proteins were involved in translation/folding, iron ion binding, and protease inhibition, whereas proteins involved in signaling, ubiquitination, and splicing were decreased in expression. These results show that it is possible to use 2-DE to separate high abundant proteins in breast cancer tissue and to find discriminating proteins to identify patients with different prognosis after adjuvant CMF treatment.

Adult↗
PubMed2004

Development of a robust microtiter plate-based assay method for assessment of bioactivity.

A microtiter plate-based assay was developed for the quantitative monitoring of bioactive compound production in Streptomyces hygroscopicus fermentation samples. The method reported demonstrates the successful application of the theories of disk diffusion based methods of bioactivity assessment, to a microtiter assay for high throughput analysis. The assay method facilitates the generation of the dose-response curve of test organisms (Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae) to a bioactive compound. Using this dose-response curve, the method facilitates definition of three distinct Minimum Inhibitory Concentration (MIC) values for use in the characterisation of the bioactive attributes of a sample. The assay uses established standard procedures to facilitate adaptation of the assay for use with a wider range of test microorganisms. Errors due to the assumption of a linear relationship between turbidity and biomass concentration are also reduced, due to incorporation of a step to convert turbidity to biomass concentration, for use in the calculation of bioactivity.

Anti-Bacterial Agents↗