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PubMed1993

Importance of methodology in the interpretation of factors affecting degradation of dung.

Many factors affect dung degradation and colonization, including the location, composition, moisture content, weight, surface area and organic matter content of dung pats. Because of the number and variability of these factors, methodology plays a major role in studies using the dung pat as an experimental unit. For results of such studies to be meaningful, conditions should be standardized as much as possible and the sampling technique should be systematic and consistent. This paper reports the results of experiments or trials which pay particular attention to aspects of methodology.

Animal Feed↗
PubMed2005

An assessment of extraction and assay techniques for quantification of calpain and calpastatin from small tissue samples.

Our objective was to evaluate whether small (biopsy-sized) samples could be used to measure calpain and calpastatin activities in skeletal muscle. The accuracy of different separation and assay methods for the quantification of calpains and calpastatin from small (1.0 and 0.2 g) skeletal muscle samples was tested. In Exp. 1, the LM was removed from six lambs, and a 50-g subsample was processed using the reference method (DEAE-Sephacel chromatography and casein assay). Subsamples (1.0 and 0.2 g) also were processed using the two-step separation (1 mL DEAE-Sephacel and bulk elution using 200 and 400 mM NaCl) and heated calpastatin methods; in both cases, fractions were assayed with Bodipy-labeled and [14C]-labeled casein microassays. Finally, casein zymography was used to separate and quantify the calpain proteases from 1.0-and 0.2-g samples. The values obtained after processing the 50-g sample using the reference method were judged most accurate, and the alternative approaches were compared with these. For each extraction and assay approach, we considered: 1) the effect of the sample size on the mean activity; 2) increased or decreased variation of data; and 3) the correlation relative to the reference method. Where possible, we compared the ratio of calpain to calpastatin activities determined using the alternative approaches with the ratios found using the reference method. These methodologies were further investigated in Exp. 2, where single homogenates from different tissues (heart, spleen, lung, and muscle) were assayed using the alternative approaches. Experiment 1 established that most of the approaches suffered from poor correlations and/or unacceptable variation. By using a large, homogenous sample in Exp. 2, however, we determined that this error was not due to the methodologies themselves. Therefore, the unacceptable variation found in Exp. 1 resulted from the small sample size, and we recommend that large tissue samples (e.g., 50 g) should be used for calpain and calpastatin activity measurements in skeletal muscle instead of small tissue biopsies (e.g., 0.2 and 1.0 g).

Animals↗
PubMed2005

Genetic algorithm for analysis of mutations in Parkinson's disease.

OBJECTIVE: Mitochondrial genetics has unique features that impede analysis of the biological significance of mitochondrial mutations. Simple searches for differences in total mutational load between normal and pathological samples have been frequently unrewarding, raising the possibility that more complex patterns of mutations may be responsible for some conditions. We explore this possibility in the context of Parkinson's disease (PD). METHODS AND MATERIALS: We report the development of a modified genetic algorithm suited for detection of biologically meaningful patterns of mitochondrial mutations. The algorithm is applied to a database of mutations derived from biological samples, and verified by the use of shuffled data, and repeated leave-one-out testing. RESULTS: It is possible to derive, from a very small sample, multiple accurate classifier functions that correlate with biological features. The methodology is validated statistically through experiments with fabricated data. CONCLUSION: This algorithm might be generally applicable to conditions where interactions among multiple mitochondrial DNA mutations are important. The patterns embodied in the classifier functions obtained should be the subject of further experimental study.

Algorithms↗
PubMed1992

[Methods in continuing professional education. Results of a pilot survey of physicians].

There is not enough evidence, that formal continuing education can improve the quality of patient care. A model to support the work of quality circles by improving the acquisition of new knowledge and skills through problem-based learning in small groups was suggested in 1991. The results of a pilot survey carried out in three different groups of physicians and professional health care workers gave evidence that the model is acceptable in Germany, where problem-based learning is virtually unknown. Attributes of study groups like inclusion of nonphysicians, who would also be accepted as moderators, were indicated by a great majority. Topics and groups should be chosen by the individual and not be imposed by a central organization. Of the four methods suggested for problem-solving-presentation of the solution by an expert, solving the problem in group work, advice from an external expert, use of electronic publications--at least three were selected by 62, 65 and 96% of the responders in the three different groups. 30% of the total of 108 responders favor all four methods. Three of the four tasks of organizations responsible for continuing education are accepted: 1. support of local study groups, 2. provision of consulting experts, 3. instillation of information centers using modern information technology. Production and application of case simulations to be used in the study groups were only accepted by 23%. The differences between groups could have been caused by external influence such as experience with case presentations. The results justify a survey with improved and extended methodology in a sample of doctors representative for the physicians working within the frame work of social insurance.

Education, Continuing↗
PubMed2004

A double concern: grandmothers' experiences when a small grandchild is critically ill.

Grandmothers play an active part in family health and illness, but so far they are peripheral in both nursing and nursing research. This article addresses grandmothers' lived experiences when a small grandchild is critically ill. A convenience sample of 7 grandmothers was interviewed once. With the use of the methodology of Van Manen, (1990), the essence of the phenomenon was found to be a "double concern," a worry and loving care that encompassed both parents and grandchildren. Although the findings have limitations, they constitute a systematic and thematic description of Danish grandmothers' experiences and therefore add to a family-oriented body of knowledge in pediatric nursing.

Anecdotes as Topic↗
PubMed2002

A qualitative study of the experiences of a group of Hong Kong Chinese women diagnosed with postnatal depression.

AIM OF THE STUDY: To examine the lived experiences of a group of Hong Kong Chinese women diagnosed with postnatal depression. BACKGROUND: Postnatal depression affects approximately 1 in 10 childbearing women in Hong Kong. However, most studies of postnatal depression have been carried out in Western societies and no qualitative research was found describing the experience of Hong Kong Chinese mothers with postnatal depression. DESIGN: A phenomenological study was conducted. Data were collected by semi-structured interviews. A purposive sample of 35 women diagnosed with postnatal depression was interviewed. Interview data were analysed following Colaizzi's phenomenological methodology. RESULTS: Themes that emerged describing participants' experiences included trapped in the situation, ambivalent towards the baby, uncaring husband, and controlling and powerful in-laws. Women felt hopelessness, helplessness and loss of control. They were trapped in a situation that had no way of escape except by violent means, such as homicide or suicide. Feelings towards the baby were ambivalent, both hate and love. Several women had injured, or had thought of injuring or killing, their babies and/or themselves. Women's unhappiness was attributed to a noncaring husband, and controlling and powerful in-laws. Generally, women did not seek help until their depression was diagnosed by screening tests. CONCLUSION: This study has revealed insights into how women experienced postnatal depression in Hong Kong, and what they perceived as contributing to their depression. These insights may be used to guide interventions for women and their families to raise awareness regarding the support childbearing women need.

Adaptation, Psychological↗
PubMed2001

Impact of the Oregon Health Plan on children with special health care needs.

OBJECTIVE: Although an increasing number of Medicaid children are enrolled in Medicaid managed care plans, little is known about how children with special health care needs fare under such programs. Of particular concern is the ability of such children to navigate a managed care system and gain access to specialty and other services. This study compares the managed care experiences of children with and without special care needs in the Oregon Health Plan. METHODOLOGY: Telephone surveys were conducted with a sample of parents of children enrolled in the Oregon Health Plan. Three groups of children were sampled: Supplemental Security Income (SSI) children with disabilities, children with asthma, and children without special health care needs. Descriptive and multivariate analyses were conducted to determine the impact of Medicaid managed care on access and satisfaction. RESULTS: Children with disabilities in managed care plans did not experience any more difficulty accessing needed specialty care than did those without special health care needs. Children with asthma, however, reported higher levels of unmet need. There were no differences in access between children with disabilities enrolled in managed care and those children with disabilities remaining in fee-for-service. CONCLUSIONS: Unlike SSI children with disabilities, children who were not SSI-eligible but had asthma seemed to have difficulty obtaining some services. These children were not eligible for the same consumer protections afforded SSI children by Oregon. If states want to enroll all children with special health care needs into managed care programs, they must develop mechanisms for identifying such children and ensuring that they receive medically necessary services.

Asthma↗
PubMed2006

Typologies of rural lay-health advocacy among rural women in Australia.

BACKGROUND: Public health advocacy effects changes in health behaviors and outcomes through applying health promotion expertise to specific groups. Advocacy occurs through the provision of tools to empower those who are either experiencing, or at risk of, a particular health status. RESEARCH OBJECTIVES: Health-care experiences of women living in rural Victoria, Australia, were explored in the context of generally poor access to reproductive health services. Women's experiences are investigated within the theoretical framework of lay-health advocacy, i.e. relying on individual health care experience and knowledge to promote and improve the health care of others. METHODOLOGY: The study applied a qualitative design, and a self-identified sample of women was recruited through network sampling techniques. Fifty-seven women participated in in-depth interviews. RESULTS: Three types of lay-health advocacy emerged. Advocacy-seekers expected the researchers to use their experiences of poor health-care to educate health professionals to provide better quality care. Advocacy providers used their knowledge and experiences to take an active part in promoting the health-care of other women. Story-tellers expected their narratives to empower other women or unidentified social groups to feel less isolated in their health care experiences. DISCUSSION: In providing narratives of their health-care, women were critical of social inequalities facing people living in rural Australia. Lay-health advocates offer a cost-effective and appropriate option for reducing adverse health outcomes within resource-poor settings. Informed by women's narratives, we suggest strategies to enhance rural women's health-care.

Adult↗
PubMed1999

Reproducibility and validity of radioimmunoassays for urinary hormones and metabolites in pre- and postmenopausal women.

The reproducibility of RIAs of circulating sex hormones has been evaluated as part of recent epidemiological investigations, but none seem to have addressed the reproducibility or validity of RIAs for urinary hormones or their metabolites. As part of a case-control study of breast cancer in Asian-American women, 12-h overnight urine samples were obtained, and a methodological study was conducted to identify laboratories capable of assaying urinary hormones. For the reproducibility component of this study, two laboratories with extensive experience in hormone assays measured urinary estrone, estradiol, estriol, pregnanediol glucuronide, and estrone glucuronide using samples from 15 women (5 midfollicular, 5 midluteal, and 5 postmenopausal). Variance estimates from these measurements were used to calculate the laboratory variability (coefficient of variation) and to assess the magnitude of the biological variability among the women in relation to the total variability (intraclass correlation coefficient). For the validity component, urinary estrone, estradiol, and estriol levels were measured in the same samples by gas chromatography-mass spectroscopy in the laboratory of Dr. Herman Adlercreutz (University of Helsinki, Helsinki, Finland). We found that the degree of assay reproducibility differed between the laboratories, but that laboratory variability was usually low compared with the range of hormone values among women, particularly for the estrogens. Values for estrone and estradiol were well correlated among all of the laboratories. For estriol, the RIAs tended to overestimate levels compared with gas chromatography-mass spectroscopy. In one laboratory, assays for pregnanediol glucuronide and estrone glucuronide were consistently reproduced; in the other, the reproducibility of the RIA for pregnanediol glucuronide was problematic, and estrone glucuronide was not measured. Despite some limitations, urinary hormones and their metabolites can be reliably measured by current RIAs in large investigations attempting to link hormone level to disease risk and may be particularly advantageous for studies of postmenopausal women, where serum concentrations of estrone and estradiol are low and assay measurements are not as dependable.

Adult↗
PubMed2004

Result-driven strategies for protein identification and quantitation--a way to optimize experimental design and derive reliable results.

Uni- or multidimensional microcapillary liquid chromatography (microLC) matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry (MS/MS) approaches have gained significant attention for quantifying and identifying proteins in complex biological samples. The off-line coupling of microLC with MS quantitation and MS/MS identification methods makes new result-dependent workflows possible. A relational database is used to store the results from multiple high performance liquid chromatography runs, including information about MALDI plate positions, and both peptide and protein quantitations, and identifications. Unlike electrospray methodology, where all the decisions about which peptide to fragment, must be made during peptide fractionations, in the MALDI experiments the samples are effectively "frozen in time". Therefore, additional MS and MS/MS spectra can be acquired, to promote more accurate quantitation or additional identifications until reliable results are derived that meet experimental design criteria. In the case of what can be designated the expression-dependent workflow, quantitation can be detached from identification and only peak pairs with biological relevant expression changes can be selected for further MS/MS analyses. Alternatively, additional MS/MS data can be acquired to confirm tentative peptide mass fingerprint hits in what is designated a search result-dependent workflow. In the MS data-dependent workflow, the goal is to collect as many meaningful spectra as possible by judiciously adjusting the acquisition parameters based on characteristics of the parent masses. This level of sophistication requires the development of innovative algorithms for these three result-dependent workflows that make MS and MS/MS analysis more efficient and also add confidence to experimental results.

Chromatography, High Pressure Liquid↗
PubMed2000

Tension and stretch receptors in gastrointestinal smooth muscle: re-evaluating vagal mechanoreceptor electrophysiology.

Electrophysiological and morphological analyses of vagal mechanoreceptors in the gut wall suggest conflicting conclusions. Electrophysiology has distinguished a single general class of ending in smooth muscle, one characterized as an 'in series' tension receptor. Morphology, in contrast, has characterized two distinct specializations of vagal afferent endings in the muscle wall of the gastrointestinal (GI) tract. These two structures differ in terms of their target tissues, terminal architectures and regional distributions; they also develop on different ontogenetic timetables and depend on different trophic support in the muscle wall. On the basis of these features, we have proposed that one of the putative mechanoreceptors, the intraganglionic laminar ending (IGLE), has characteristics of a tension receptor and the other, the intramuscular array (IMA), has features of a stretch or length receptor. In a functional analogy with striated muscle proprioceptors, IGLEs should have similarities to Golgi tendon organs, whereas IMAs should have equivalencies with muscle spindle afferents. The present survey re-examines the recording analyses in light of the structural observations. This review indicates that previous electrophysiological studies are too inconclusive to refute the inference that the vagus supplies two distinct types of mechanoreceptors to the muscle wall of the GI tract. Multiple methodological constraints and sources of variance have limited the resolution of electrophysiological experiments. Specifically, these experiments have conventionally used distension stimuli that confound tension and stretch. In addition, sampling strategies have biased recording experiments towards a focus on one type of ending, the IGLE. Furthermore, putative functional properties (e.g., broad tuning) of vagal mechanoreceptors suggest that distinguishing two recording patterns will require exacting protocols. Combining a recognition of the methodological difficulties that have limited electrophysiological analyses with an understanding of the structural features of the endings, however, suggests several critical electrophysiological experiments with the resolution to distinguish two classes of response profiles. Until such experiments can be conducted, sensory physiology's axiom that 'function varies with form', taken together with a re-assessment of the existing data, suggests that the vagus nerve supplies stretch receptors as well as tension receptors to the wall of the GI tract.

Animals↗
PubMed2004

Liver biopsy sampling in chronic viral hepatitis.

In chronic viral hepatitis, liver biopsy is performed to grade and stage liver damage. Liver biopsy samples are usually taken with a needle using a percutaneous procedure. This method produces a core of tissue representing approximately 1/50,000th of the liver mass, which raises concern about how representative a needle biopsy can be. A critical review of the literature reveals methodological limits unacceptable in this era of evidence-based medicine. Integrating earlier experience with more recently produced data indicates that a biopsy sample 2 cm or more in length containing at least 11 complete portal tracts should be reliable for grading and staging chronic viral hepatitis.

Biopsy↗
PubMed1989

High specific activity chemiluminescent and fluorescent markers: their potential application to high sensitivity and 'multi-analyte' immunoassays.

The sensitivities of immunoassays relying on conventional radioisotopic labels (i.e. radioimmunoassay (RIA) and immunoradiometric assay (IRMA) permit the measurement of analyte concentrations above ca 10(7) molecules/ml. This limitation primarily derives, in the case of 'competitive' or 'limited reagent' assays, from the 'manipulation errors arising in the system combined with the physicochemical characteristics of the particular antibody used; however, in the case of 'non-competitive' systems, the specific activity of the label may play a more important constraining role. It is theoretically demonstrable that the development of assay techniques yielding detection limits significantly lower than 10(7) molecules/ml depends on: (1) the adoption of 'non-competitive' assays designs; (2) the use of labels of higher specific activity than radioisotopes; (3) highly efficient discrimination between the products of the immunological reactions involved. Chemiluminescent and fluorescent substances are capable of yielding higher specific activities than commonly used radioisotopes when used as direct reagent labels in this context, and both thus provide a basis for the development of 'ultra-sensitive', non-competitive, immunoassay methodologies. Enzymes catalysing chemiluminescent reactions or yielding fluorescent reaction products can likewise be used as labels yielding high effective specific activities and hence enhanced assay sensitivities. A particular advantage of fluorescent labels (albeit one not necessarily confined to them) lies in the possibility they offer of revealing immunological reactions localized in 'microspots' distributed on an inert solid support. This opens the way to the development of an entirely new generation of 'ambient analyte' microspot immunoassays permitting the simultaneous measurement of tens or even hundreds of different analytes in the same small sample, using (for example) laser scanning techniques. Early experience suggests that microspot assays with sensitivities surpassing that of isotopically based methodologies can readily be developed.

Antibody Affinity↗
PubMed1994

Screening: assessment of current studies.

BACKGROUND: A major issue in decisions regarding screening women for breast cancer concerns ages of coverage, in particular, whether routine mass screening programs with mammography should cover women aged 40-49. Interpretation of results of studies on this question is affected by differences in design, adequacy of sample size, quality of mammography, period of follow-up, and other methodologic and content issues. METHODS: Experience in eight randomized controlled trials (RCTs) conducted over the past 30 years in the United States, Europe, and Canada were assessed, and problems influencing their conclusions were considered. RESULTS: The age groups studied in these RCTs varied, from 40-64 in the Health Insurance Plan (HIP) study to 40-74 in the Swedish two-country trials. In addition, they differed in periodicity and modalities of screening, with the HIP and the Canadian National Breast Screening Study providing annual examinations with mammography and clinical breast examination, and most of the other trials scheduling longer intervals between examinations with mammography alone. Great consistency is found, however, in the results for women aged 50-69, as all of these studies showed a reduction in breast cancer mortality in this age group, suggesting about a 30% decrease. For women aged 40-49, the studies showed no benefit 5-7 years after entry and an uncertain benefit 10-12 years after entry, and only one study offered information on long term effects. Additional follow-up is needed. Adequate data are not available for women 70 and older. CONCLUSION: Public health policy on mass screening with mammography for women aged 40-49 is questionable. At this time, the emphasis should be on physicians advising women about the uncertainty of the benefits of routine mammography when referrals are being considered.

Adult↗
PubMed1984

Ultrastructural studies of concanavalin A receptors and 5'-nucleotidase localization in normal and injured mouse cerebral microvasculature.

Plant lectin concanavalin A conjugated with ferritin (Con A-F) injected i.v. was used for the detection of the specific monosaccharide residues (alpha-D-mannosyl and alpha-D-glucosyl) on the luminal surface of endothelial cells (ECs) in brain micro-blood vessels (MBVs). Both normal mice and animals with mechanically damaged blood-brain barrier (BBB) were used in this study. In addition, the activity of 5'-nucleotidase (5'N), the putative receptor for Con A, was studied cytochemically. Various methodologic experiments indicated that the reaction product formed on the luminal plasmalemma of ECs after incubation of samples in the cytochemical medium for the detection of 5'N activity results from the action of unspecific phosphatase hydrolyzing both specific and nonspecific substrates. The abluminal side of the wall of MBVs seems to be a major location of 5'N activity. Thus, no correlation between cytochemically demonstrable 5'N activity and Con A receptor sites on the luminal surface of ECs was noted. After damage of the BBB, extensive internalization of the luminal plasmalemma forming the limiting membranes of pinocytotic vesicles, vacuoles, and endothelial channel-like structures was observed. This process was represented by a relatively rapid translocation of Con A receptors from luminal surface into the interior of the ECs and to the abluminal side of the vessel wall.

5'-Nucleotidase↗
PubMed1999

[Education and health services: evaluating professional training].

This paper analyzes the results of a follow-up study and evaluation of the Specialization Course in Public Health administered from 1993 to 1995 by the Department of Preventive and Social Medicine at the School of Medical Sciences, Universidade de Campinas, Brazil. The study was conducted during the course and with a follow-up several months later. Students reported on their professional activities, difficulties and facilities in performing them, and their commitment to the public health services in which they worked. They also expounded on their needs and expectations regarding specialized training in public health. At the end of the required course load (first semester) and the optional courses (second semester), students evaluated the course content's relevance, their own understanding, and the strengths and weaknesses of the respective teaching strategies. Finally, six and eight months after the courses, the professionals evaluated how they were able to apply their new knowledge to their work. Various research instruments were used, including group dynamics, individual questionnaires, and focal groups, comprising a broad methodological approach. A single sample of individuals was thus studied at different moments with regard to this experience.

Brazil↗
PubMed2004

Paternal absence and international migration: stressors and compensators associated with the mental health of Mexican teenagers of rural origin.

Mexico-U.S. migration creates situations that may cause psychological distress. The purpose of this research project was to study the impact of father's physical absence due to international migration (FPAIM) on adolescent offspring of rural immigrants from Zacatecas, Mexico. Stressors and compensators were studied from the adolescent's perspective and were analyzed using a stress-mediator-consequences theoretical framework. Qualitative (n = 24) and quantitative (n = 310) methodologies were used with a nonrandom sample of adolescents. Results show that the FPAIM is an ambivalent experience for adolescents that has positive and negative elements. Though migrants' children seem to be more vulnerable to psychosocial stress than are the offspring of nonmigrants, gender, not father's absence, appears to be the most important risk factor for psychological distress.

Adolescent↗
PubMed1990

Appraisal of the quality of assessment of memory in anesthesia and psychopharmacology literature.

To test the hypothesis that there are important differences between studies on memory published in anesthesia literature and those published in the psychopharmacology literature, we compared the two from the period January 1978 through May 1988 to identify deficiencies in the design and methodologies used and to provide guidelines for future experiments. Eight-eight articles in each discipline were reviewed. The sample sizes were larger in the articles in anesthesia journals than in those in psychopharmacology journals (medians 52.5 vs. 18 subjects, respectively). Most (85%) of the studies in the anesthesia literature used patients, who had a median age of 38.9 yr and included a median of 28 women among the subjects per study. In contrast, the majority (60%) of the studies in the psychopharmacology literature used healthy volunteers, who had a median age of 23.6 yr and included a median of only 3.5 females among the subjects per study. Characteristics more common in the psychopharmacology than in the anesthesia literature, respectively, were use of a control or placebo group (90% vs. 42%), double-blind design (80% vs. 47%), use of pre- and posttreatment memory measurements (64% vs. 23%), use of multiple memory tests with distinct equated stimuli (83% vs. 8%), relation of methodology to some theoretical model of memory (72% vs. 17%), and use of other behavioral tests (68% vs. 48%). Relative to the psychopharmacology literature, the anesthesia literature used pictures as stimuli for the memory tests more often (44% vs. 14%, respectively) and words less often (11% vs. 67%) and relied heavily on questions about recall of perioperative events (41% vs. 0%). There is room for improvement in both types of literature, and more so in the anesthesia literature.

Anesthesia↗