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PubMed1988

Purification of glutathione S-transferases from rat liver and Walker 256 mammary carcinoma cells by high-performance liquid chromatography and a glutathione affinity column.

A novel method for the rapid purification of glutathione S-transferases (GST) from tissue and cell culture samples is reported. A high-performance glutathione affinity column was used and produced results comparable to those obtained with classical agarose affinity columns. Experiments with purified rat liver GST standards resulted in 87% recovery of total activity. Sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE) of the affinity-purified GST was identical to the GST standard and revealed three major protein bands, corresponding to the Ya, Yb, and Yc subunits. A fourth protein band (relative molecular mass 25,000), migrating slightly faster than the Ya subunit, was present in both the standard and eluted GST samples. This polypeptide was tentatively identified as the Yk subunit. Successful purification from rat liver and Walker 256 rat carcinoma cell cytosols was also performed. Recovery of total GST enzymatic activity from Walker cell and rat liver cytosol was 49 and 58%, respectively. SDS-PAGE of these samples indicated a high degree of purity. This methodology requires less than 1 h and can be performed using small quantities of tissue. These features make this technique applicable to analysis of a broad range of biological applications including human biopsy material for GST content.

Animals↗

PubMed2005

A meta-analytic investigation of the relationship between the psychological distress of cancer patients and their carers.

The identification of factors that might affect the relationship between patients' and carers' psychological distress has received insufficient attention to date. A meta-analysis was conducted with 21 independent samples of cancer patients and their carers, to quantify the relationship and difference between respective measures of psychological distress. Correlation coefficients and standard differences were extracted from 21 studies that met pre-defined inclusion criteria. Random effects models were used. Variables that modified this relationship were examined with potential causes of heterogeneity explored. Analysis confirmed the positive association between patient and carer psychological distress (r = 0.35, P<0.0001), and indicated that patients and carers did not experience significantly more or less psychological distress than one another (P = 0.64). Subgroup analysis was performed to explore potential sources of heterogeneity, and initial findings indicated a relationship between time since diagnosis and the strength of correlation between patient and carer psychological distress. The meta-analysis was limited by the large clinical and methodological variability between studies, and further systematic prospective research is required. This preliminary evidence suggests that early intervention with the patient and their carer could prevent later development of psychological distress in both members.

Caregivers↗

PubMed1982

Quality control of amitriptyline and nortriptyline plasma level assessments: a multicenter study.

Numerous studies report about the relationship between the clinical effectiveness of amitriptyline (At) and the plasma level of this drug and of its most important metabolite, nortriptyline (Nt). These agents are therefore very frequently examined for clinical applications and for research programmes in specialized laboratories. The experience with antiepileptic drugs suggests the necessity of quality controls for antidepressants also. Therefore, five institutions in Western Europe performed two such experiments within a year. Two kinds of blood samples were sent for analysis: 1. plasma samples spiked with different quantities of At and Nt from an untreated subject; 2. plasma samples from patients treated with clinical doses of At. Each laboratory happened to use a different analytical method: TLC, HPLC, GC-NPD, GC-FID and GC-MS. The results clearly show the usefulness and the necessity of quality controls for this category of drugs as well. They form the basis for the improvement of the methods of each laboratory in particular. In this context, intralaboratory quality controls are also possible, if one disposes of two different methods. The findings of this study suggest that published reports on relationships between clinical and pharmacological parameters should be considered critically as to possible methodological bias.

Amitriptyline↗

PubMed2002

The Research Forum for MPH students.

Over the years, the experience with the Research Forum has shown that the framework is effective in providing the time frame and the academic support for the preparation of the proposals. It provides the students with an additional opportunity for the integration of knowledge gained during the MPH core and elective courses and for developing skills in writing and appraising a proposal or an essay on a public health issue. For the faculty it is another instance in which methodological issues are stressed, public health themes are discussed, and a systematic approach is emphasized. This process helps the students to achieve high academic levels for their proposals, and the final theses or papers are enhanced. This is evidenced by the fact that many of these works are also published in peer-reviewed journals, a sample of which is shown in the references. Students from Countries of Eastern Europe and the Commonwealth of Independent States have the opportunity to apply to the Soros Foundation Open Society Institute (OSI) for projects on their return to their home institution, which may include a continuation of their research project or master's paper topic. This project is to be carried out during the first year of their return home with financial support up to $5,000. These projects have been presented to Braun SPH faculty at summer seminars held in Russia in 2001 and 2002.

Academic Dissertations as Topic↗

PubMed2003

Identity shifts as turning points in health behavior change.

The authors used a grounded formal theory approach to synthesize the findings of 14 studies, with the goal of identifying common elements in qualitative studies of individuals' efforts to change a variety of unhealthy behaviors. The combined sample of 399 participants had experiences of weight loss, smoking cessation, and alcohol and drug-abuse recovery. Data were extracted from published reports and analyzed using grounded-theory techniques. In the provisional model, a value conflict in response to distressing accumulated evidence prompts a small step toward behavior change. If successful, an identity shift begins. Increased self-awareness and self-confidence fuel continued change. Numerous constraints to success are noted at each step. The links to previous conceptions of identity shift are discussed.

Health Behavior↗

PubMed1994

Acquisition of blood, injury, and needle fears and phobias.

The origins of fear and phobia of blood, injury, and injections were investigated in a sample of 128 fearful university students. Based on Mutilation Questionnaire scores, subjects were designated as common fear, high fear, or phobic. Ss reports of their onset experiences obtained from structured interviews were categorized into one or more acquisition pathways of conditioning, vicarious observation, and information. Of the 73% of Ss who recalled one or more onset experiences, 76% reported conditioning-like events as the primary pathway with the majority reporting fear-related UCSs. Vicarious experiences were reported as primary by 20% and 3% reported information as being primary in their fear onset. Severity of fear was unrelated to the pathway by which it was acquired, to whether the onset was recalled, and if recalled, whether it was due to a single or to multiple traumatic events. Results are discussed in terms of methodological problems of memory issues and means by which data are collected.

Adolescent↗

PubMed2003

Age of menarche: the role of some psychosocial factors.

BACKGROUND: The goal of this study was to determine associations between the age of first menstrual period (menarche) and adverse childhood experiences in a random community sample of New Zealand women. Previous reports have linked early menarche to absence of a live-in father figure and to family conflict, as well as genetic determination of early puberty and adiposity. METHOD: Two groups of women randomly selected from the community on their responses to a mailed screening questionnaire on childhood sexual abuse (CSA) were interviewed in detail. Data about their childhood experiences, including age of menarche, were collected on two occasions, 6 years apart. Early menarche was defined as first menstruation occurring before the age of 12 years. RESULTS: Univariate analyses identified a number of adverse childhood experiences preceded early menarche, which was reported by 20.3% of this sample. These included low family socio-economic status, absence of father, a number of variables showing family conflict, poor relationships between the girl and either/both parents, a self-rated childhood personality style as a loner, childhood physical and sexual abuse. Sequential modelling showed parental rows, being a loner and the duration of CSA to be most important, although lack of a father and any CSA were each also independently associated with early menarche. No variables survived the modelling exercise as predictors of early menarche for those women who did not report childhood sexual abuse. CONCLUSIONS: The identified variables statistically interacted with each other in a highly complex manner. The attempt to rank their importance was only partially successful, for methodological reasons (half the sample reporting CSA). Chronic or protracted CSA needs to be added to the list of factors associated with early menarche in future studies.

Adult↗

PubMed1988

Survey of general practitioners' attitudes to AIDS in the North West Thames and East Anglian regions.

As the numbers of people suffering from human immunodeficiency virus infection and the acquired immune deficiency syndrome (AIDS) increase, so will the contribution to care required from general practice. A postal questionnaire survey was therefore carried out among general practitioners in the North West Thames and East Anglian regions to determine their attitudes to AIDS and the issues it raises for them. One hundred and thirty seven questionnaires were returned (response rate 57%) and four factors underlying the doctors' attitudes identified; these concerned disease control, general practitioner care, patient support, and perception of seriousness. There were wide divergences of attitude among the general practitioners, younger doctors being more in line with specialist thinking on AIDS than older colleagues, and evidence of important gaps between policies advocated by AIDS specialists and bodies of opinion in general practice. Attitudes to AIDS in general practice may partly be a function of personal experience; further study is required.

Acquired Immunodeficiency Syndrome↗

PubMed1998

PCR for HBV, HCV and HIV-1 experiences and first results from a routine screening programme in a large blood transfusion service.

We adapted the PCR method to screen up to 3000 blood donations per day for hepatitis B, hepatitis C and HIV-1 virus contamination. Up to 600 aliquots (average 418 donations) are pooled by using an automatic sample processor with disposable tips (validated to avoid contamination) taken from blood donations which are serologically negative and free for clinical usage according to federal regulations. In the case of a positive PCR pool result the viraemic donation is identified by two additional PCR pools testing steps with smaller pool sizes. All of the steps are supported by electronic data processing. After virus concentration by ultracentrifugation, and in the case of HCV and HIV-1 an additional reverse transcription step, PCR amplifications are performed. PCRs are done for each virus in two genomic regions. Laser-induced detection after PAGE and computer-analysis are used to identify the amplification products. Using this validated methodology routine we have checked 428 896 donations up to the end of August 1996. During this survey we found at least 24 viruses-containing donations which were negative in corresponding serological tests and would have been transfused (2 HBV-, 22 HCV-, 0 HIV-1 -containing donations). It seems possible for large transfusion centres to shorten the diagnostic window periods with our PCR-methodology with acceptable costs (15 DM per donation for all three viruses including logistics, developments and investments).

AIDS Serodiagnosis↗

PubMed1995

Advanced interactive planning techniques for conformal therapy: high level beam descriptions and volumetric mapping techniques.

PURPOSE: To aid in design of conformal radiation therapy treatment plans involving many conformally shaped fields, this work investigates the use of two methodologies to enhance the ease of interactive treatment planning: high-level beam constructs and beam's-eye view volumetric mapping. METHODS AND MATERIALS: High-performance computer graphics running on various workstations using a graphical visualization system (AVS) have been used in this work. Software specific to this application has been written in standard FORTRAN and C languages. A new methodology is introduced by defining radiation therapy "fields" to be composed of multiple beam "segments." Fields can then be defined as higher-level entities such as arcs, cones, and other shapes. A "segmental cone" field, for example, is defined by a symmetry axis and a cone angle, and can be used to rapidly place a series of beam segments that converge at the target volume, while reducing the degree of overlap elsewhere. A new beam's-eye view (BEV) volumetric mapping technique is presented to aid in selecting the placement of conformal radiation fields. With this technique, the relative average dose within an organ of interest is calculated for a sampling of isocentric, conformally shaped beams and displayed either as a "globe," which can be combined with the display of anatomical surfaces, or as a two-dimensionally mapped projection. The dose maps from multiple organs can be generated, stacked, or composited with relative weightings to aid in the placement of fields that minimize overlap with critical structures. RESULTS: The use of these new methodologies is demonstrated for prostate and lung treatment sites and compared to conventional planning techniques. DISCUSSION: The use of many beams for conformal treatment delivery is difficult with current interactive planning. The use of high-level beam constructs provides a means to quickly specify, place, and configure multiple beam arrangements. The BEV volumetrics aids in the placing of fields, which minimize involvement with critical normal tissues. CONCLUSIONS: Early experience with the new methodologies suggest that the new methods help to enhance (or at least speed up) the ability of a treatment planner to create optimal radiation treatment field arrangements.

Evaluation Studies as Topic↗

PubMed1997

Thermodynamic stability of the asymmetric doubly-ligated hemoglobin tetramer (alpha+CNbeta+CN)(alphabeta): methodological and mechanistic issues.

Free energy contributions to cooperativity by the eight ligation intermediates of human hemoglobin (Hb) have been characterized extensively using six oxygenation analogs [cf. Huang et al. (1996) Biophys. J. 71, 2094-2105, Table 2]. These unprecedented data bses have strongly supported the molecular code mechanism of Hb cooperativity [Ackers et al. (1992) science 255, 54-83]. The present study addresses a recent argument against this work [Shibayama et al. (1997) Biochemistry 36, 4375-4381] based on "free energy" determinations for a doubly-ligated species of the CN-met analog. Shibayama et al. (1997) have claimed that, in the hybridization experiments that have been used to determine free energy of the asymmetric "species[21]" tetramer, a portion of the bound cyanide is allegedly released from CN-met Hb during the incubation with deoxy Hb that is used to achieve hybrid equilibrium. These authors have claimed that cyanide release has resulted in extensive electron exchange between heme sites of the hybridizing sample, leading to incorrect evaluation of the equilibrium species population by the cryogenic techniques that have been employed. In this report, we demonstrate that neither appreciable cyanide loss nor electron exchange occurs with the methods that have been used extensively by our two laboratories for these equilibrium determinations [Perrella et al. (1990) Biophys. Chem. 35, 97-103; Daugherty et al. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 1110-1114]. An alternative experiment, which Shibayama et al. (1997) have carried out to illustrate their claim, does not evaluate a thermodynamic equilibrium property of the species [21] hybrid. The relevance of their newly-estimated "free energy" is therefore unclear. Nevertheless, Shibayama et al. (1997) have claimed that their proposed "free energy" (which is approximately 1.3 kcal more positive than the free energy of -11.4 kcal found independently by our two laboratories) renders invalid the molecular code mechanism of hemoglobin cooperativity. This representation is utterly without foundation since a free energy even more positive than suggested by Shibayama et al. (1997) would be fully consistent with the molecular code mechanism.

Animals↗

PubMed1996

Studies on the role of urinary macromolecules in urolithiasis: review of methodologies and a proposal for a standard reference crystallization system.

In this study, urine from a calcium oxalate kidney stone former was ultrafiltered (10 kD cut-off). Crystallization was induced in the ultrafiltrate and retentate fractions as well as in a sample of the whole urine. The progress of crystallization was monitored by Coulter Counter and flow cytometry techniques. (The latter has not been used in studies of the role of urinary macromolecules in urolithiasis). Deposited crystals were examined by scanning electron microscopy. Results indicated that urinary macromolecules in this subject are inhibitors of nucleation and aggregation. These results agree with the findings of some workers but disagree with those of others. Indeed, studies on the role played by urinary macromolecules in promoting or inhibiting urolithiasis have failed to produce consistent findings. Examination of the literature reveals that a wide variety of experimental techniques and crystallization systems have been used in these studies and that this might be the cause of the inconsistencies. Based on reported experiences and those of the present study, a standard reference crystallization system is proposed. The key elements of this system involve the use of real urine, ultrafiltration, continuous crystallizer equipment, Coulter Counter procedures and scanning electron microscopy.

Animals↗

PubMed2004

Validation of a simplified field-adapted procedure for routine determinations of methyl mercury at trace levels in natural water samples using species-specific isotope dilution mass spectrometry.

A field-adapted procedure based on species-specific isotope dilution (SSID) methodology for trace-level determinations of methyl mercury (CH(3)Hg(+)) in mire, fresh and sea water samples was developed, validated and applied in a field study. In the field study, mire water samples were filtered, standardised volumetrically with isotopically enriched CH(3) (200)Hg(+), and frozen on dry ice. The samples were derivatised in the laboratory without further pre-treatment using sodium tetraethyl borate (NaB(C(2)H(5))(4)) and the ethylated methyl mercury was purge-trapped on Tenax columns. The analyte was thermo-desorbed onto a GC-ICP-MS system for analysis. Investigations preceding field application of the method showed that when using SSID, for all tested matrices, identical results were obtained between samples that were freeze-preserved or analysed unpreserved. For DOC-rich samples (mire water) additional experiments showed no difference in CH(3)Hg(+) concentration between samples that were derivatised without pre-treatment or after liquid extraction. Extractions of samples for matrix-analyte separation prior to derivatisation are therefore not necessary. No formation of CH(3)Hg(+) was observed during sample storage and treatment when spiking samples with (198)Hg(2+). Total uncertainty budgets for the field application of the method showed that for analyte concentrations higher than 1.5 pg g(-1) (as Hg) the relative expanded uncertainty (REU) was approximately 5% and dominated by the uncertainty in the isotope standard concentration. Below 0.5 pg g(-1) (as Hg), the REU was >10% and dominated by variations in the field blank. The uncertainty of the method is sufficiently low to accurately determine CH(3)Hg(+) concentrations at trace levels. The detection limit was determined to be 4 fg g(-1) (as Hg) based on replicate analyses of laboratory blanks. The described procedure is reliable, considerably faster and simplified compared to non-SSID methods and thereby very suitable for routine applications of CH(3)Hg(+) speciation analysis in a wide range of water samples.

Environmental Monitoring↗

PubMed2005

Prefrontal substrates of empathy: psychometric evidence in a community sample.

Empathy is a vicarious experience of others' emotions, and is crucial to many forms of adaptive social interaction. Clinical, experimental, and functional neuroimaging studies convergently suggest a role for prefrontal-limbic circuits in mediating empathy. This study examined the prefrontal basis of empathy in a community sample using self-report measures: the frontal systems behavior scale (FrSBe), Barratt impulsiveness scale (BIS), and the interpersonal reactivity index (IRI). Multiple correlations emerged supporting an inverse relationship between prefrontal system dysfunction and empathy, particularly emotional empathy and perspective taking. Many of these relationships persisted after controlling for age, sex, and education. However, FrSBe scales did not correlate with one's identification with fictional characters, and motor impulsivity correlated positively, presumably due to the different cognitive and emotional context (i.e. real versus fictional individuals). These studies parallel others using objective methodologies and suggest a graded relationship between prefrontal function and empathy and likely reflect normal variations in prefrontal-limbic function.

Adolescent↗

PubMed1994

The effects of educational placement and grade level on the self-perceptions of low achievers and students with learning disabilities.

Previous studies have yielded mixed findings as to the effect of learning disabilities (LD) on self-perception. We proposed that perceived competence in children who experience learning difficulties is affected both by age trends in self-appraisal processes and by the degree to which students' salient reference group is composed primarily of similar or more competent others. Measures of perceived competence (Harter, 1982) and perceived achievement were administered to 222 Israeli students (127 boys, 95 girls) in Grades 3, 5, and 7. The sample comprised 68 children with LD attending special schools, 68 children with LD attending special classes in regular schools, and 86 nonidentified low achievers in regular classes. As expected, perceived competence was similar and high in all groups at Grade 3, but was higher among the special school group than among the special class and low achieving groups at Grade 5. The benefits of special schools were less clear at Grade 7. Implications for research methodology and educational practice are discussed.

Adolescent↗

PubMedDate not supplied

[Cerebral Doppler ultrasonography in newborn infants].

Following the first study of Bada et al. (1979), Doppler assessment of cerebral blood flow has increasingly been used in newborn infants, matching the technical progress in the available equipment. The experience gathered in recent years has confirmed that Doppler US is a reliable and reproducible examination while precising the limitations and the methodology to be followed in order to prevent gross errors of assessment and interpretation. The interest this procedure has arisen, among other things, stems from being noninvasive and feasible at the patient's bed. These features enable its repeated use in newborn infants in poor clinical condition. The diagnostic and prognostic role of Doppler velocimetry has been shown in a number of neonatal diseases and the cerebral hemodynamics has been assessed in physiologic conditions as well as after drug administration. The most common equipment used in newborn infants is at present Duplex Doppler consisting of a pulsed Doppler combined with bidimensional scanner, which, with visualization of study arteries, enables precise positioning of sample volume and correction of the ultrasonic angle of incidence with respect to the direction of blood flow in the examined vessel. In this report, after a survey of the techniques and modalities of cerebral Doppler examination in newborns, a review of the present state of the art, in neonatal cerebral as well as extracranial disease, is presented.

Aminophylline↗

PubMed1999

Hope and anxiety of individual family members of critically ill adults.

This correlational study describes levels of hope and states of anxiety of individual family members of critically ill patients and investigates the relationship between hope and state of anxiety. Forty-four family members of critically ill patients participated in the study and revealed a high level of hope and a high level of anxiety within 72 hours of the patient's hospitalization, regardless of personal or situational characteristics. Hope and anxiety were not significantly related in this sample; themes of hope focused on past and present experiences, whereas anxiety centered on death of the loved one. Participants looked to the past, recalling happy times, and to the future, in relation to goals and potential. Family members acknowledged feeling secure, self-confident, and steady, and were able to make decisions because they were not confused about the situation. Nurses are challenged to inspire the family's hope and decrease their anxiety.

Adaptation, Psychological↗

PubMed1976

The financing and the economic efficiency of rural health services in the People's Republic of China.

This paper studies the resource allocation in the provision of health care services at the local level in the People's Republic of China. The subject of health financing and the effectiveness and cost of this medical cooperative service in the country's rural areas are evaluated. The conclusion drawn is that, with China's agricultural economic framework, the adoption of barefoot doctor services and the promotion of herbal medicine are cost-minimizing approaches that enable local political units to be financially self-supporting with regard to medical services. Based on a few samples at brigade or commune level, the results indicate that the barefoot doctor services are economically valuable. Furthermore, the sense of security and a point of entry into the health care system that the barefoot doctors can provide for lower-income peasants are by no means a minor noneconomic benefit. Some of their experiences may be useful to other developing countries.

China↗