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PubMed2004

Glucagon and insulin response to dietary carbohydrate in rainbow trout (Oncorhynchus mykiss).

The effects of high carbohydrate (CH) diets on circulating levels of insulin and glucagon were studied in rainbow trout (Oncorhynchus mykiss). Fish (76.87 +/- 8.11 g) were fed for 60 days with three isocaloric diets: control (C) (12% CH), W (28% CH mainly from wheat), and S (28% CH from wheat plus gelatinized starch). After the diet treatment, trout fed the enriched CH diets showed a higher hepatosomatic index and liver glycogen content than controls. In addition, plasma glucose levels were also higher but, on the contrary, circulating insulin levels were greater in the control group. After the period of diet adaptation, fish were sampled 3, 6, 9, and 24 h after food administration. Glycemia levels correlated with the dietary carbohydrate content, and were minimum in controls (from 96.02 +/- 3.77 to 118.97 +/- 6.08 mg/100 ml), followed by W group (from 124.60 +/- 7.46 to 172.19 +/- 11.36 mg/100 ml) and maximum in the S group (from 133.51 +/- 9.36 to 217.88 +/- 13.36 mg/100 ml). Postprandial glucagon profiles showed an inverse relationship with glycemia, indicating that the ingestion of glucose inhibits glucagon secretion. There were no significant differences in postprandial insulin levels between groups except for W group, which presented lower levels of circulating insulin 9 h after feeding. These results indicate that in trout fed a CH diet glucose affects the secretion of glucagon more than insulin during the postprandial period.

Adaptation, Physiological↗
PubMed1993

Effects of membership in bereavement support groups on adaptation to conjugal bereavement.

Examined the contribution of membership in bereavement support groups (BSGs) to bereavement adaptation in a sample of 127 widows and widowers, 37 of whom participated in BSGs, during the first 18 months of their bereavement. Both BSG members and nonmembers exhibited significant declines in depression, anger, anxiety, subjective stress, and psychotropic medication usage over the 18-month course. Multiple regression analyses revealed that neither group membership nor level of group involvement was associated with significantly greater declines in these variables, after demographic variables, initial levels of distress, and levels of perceived social support were accounted for. In further exploratory analyses, however, the number of BSG meetings attended accounted for significant amounts of variance in levels of anger and psychotropic medication usage and interacted with perceived social support in accounting for variance in subjective stress. The extent to which these findings call into question common assumptions regarding the efficacy of BSGs and implications for future research are discussed.

Adaptation, Psychological↗
PubMed2000

The economic implications of self-care: the effect of lifestyle, functional adaptations, and medical self-care among a national sample of Medicare beneficiaries.

OBJECTIVES: Self-care includes actions taken by individuals to promote or ensure their health, to recover from diseases or injuries, or to manage their effects. This study measured associations between self-care practices (lifestyle practices, adaptations to functional limitations, and medical self-care) and Medicare expenditures among a national sample of adults 65 years and older. METHODS: Regression models of Medicare use and expenditures were estimated by using the National Survey of Self-Care and Aging and Medicare claims for 4 years following a baseline interview. RESULTS: Lifestyle factors (swimming and walking) and functional adaptations (general home modifications) were associated with reductions in monthly Medicare expenditures over a 12-month follow-up period. Expenditure reductions were found over the 48-month follow-up period for participation in active sports, gardening, and medical self-care. Practices associated with increases in expenditures included smoking, physical exercise (possibly of a more strenuous nature), and specific home modifications. CONCLUSIONS: Certain self-care practices appear to have significant implications for Medicare expenditures and presumptively for the health status of older adults. Such practices should be encouraged among older adults as a matter of national health policy.

Activities of Daily Living↗
PubMed1996

A microassay for measuring glycogen in 96-well-cultured cells.

This study describes a rapid, sensitive, and automated spectrophotometric enzymatic microassay that measures the intracellular glycogen of primary cultured hepatocytes and other cultured cells in 96-well plates and can be adapted for other samples that are transferred to these plates. The procedure involves in situ disruption of cells, followed by hydrolysis of glycogen into glucosyl units by fungal glucoamylase (exo-1.4-alpha-glucosidase, EC 3.2.1.3), and glucose determination with the glucose oxidase colorimetric method. The color intensity can be measured in conventional ELISA readers, and the data can be fed to an on-line computer for rapid processing. The advantages of this method are its simplicity and automation, the reduction in sample handling, and the small number of cells required compared to other conventional methods.

Animals↗
PubMed2001

The energetics of off-rotamer protein side-chain conformations.

Non-rotameric ("off-rotamer") conformations are commonly observed for the side-chains of protein crystal structures. This study examines whether such conformations are real or artifactual by comparing the energetics of on and off-rotamer side-chain conformations calculated with the CHARMM energy function. Energy-based predictions of side-chain orientation are carried out by rigid-geometry mapping in the presence of the fixed protein environment for 1709 non-polar side-chains in 24 proteins for which high-resolution (2.0 A or better) structures are available. For on-rotamer conformations, 97.6 % are correctly predicted; i.e. they correspond to the absolute minima of their local side-chain energy maps (generally to within 10 degrees or less). By contrast, for the observed off-rotamer side-chain conformations, 63.8 % are predicted correctly. This difference is statistically significant (P<0.001) and suggests that while most of the observed off-rotamer conformations are real, many of the erroneously predicted ones are likely to be artifacts of the X-ray refinements. Probabilities for off-rotamer conformations of the non-polar side-chains are calculated to be 5.0-6.1 % by adaptive umbrella-sampled molecular dynamics trajectories of individual amino acid residues in vacuum and in the presence of an average protein or aqueous dielectric environment. These results correspond closely to the 5.7 % off-rotamer fraction predicted by the rigid-geometry mapping studies. Since these values are about one-half of the 10.2 % off-rotamer fraction observed in the X-ray structures, they support the conclusion that many of the latter are artifacts. In both the rigid-geometry mapping and the molecular dynamics studies, the discrepancies between the predicted and observed fractions of off-rotamer conformations are largest for leucine residues (approximately 6 % versus 16.6 %). The simulations for the isolated amino acid residues indicate that the real off-rotamer frequency of 5-6 % is consistent with the internal side-chain and local side-chain-backbone energetics and does not originate from shifts due to the protein. The present results suggest that energy-based rotation maps can be used to find side-chain positional artifacts that appear in crystal structures based on refinements in the 2 A resolution range.

Amino Acids↗
PubMed1999

Analysis of the mechanical properties of in vitro reconstructed epidermis: preliminary results.

Human epidermis can be reconstructed in vitro and is currently used in autografts for the treatment of severe, extensive burns and pigmentation disorders. However, there are neither international standards nor a common nomenclature for engineered tissues. The paper discusses the results of a preliminary study on human cultured epidermis to assess its mechanical tensile strength, and to eventually establish mechanical evaluation criteria that will enable test and comparison of the behaviour of different engineered tissue products. To perform uniaxial tension tests a traditional testing machine was adapted, and dedicated sample holding frame and grips designed.

Cell Culture Techniques↗
PubMed2003

Iron analysis in atmospheric water samples by atomic absorption spectroscopy (AAS) in water-methanol.

To distinguish between Fe(II) and Fe(III) species in atmospheric water samples, we have adapted an analytical procedure based on the formation of a specific complex between Fe(II) and ferrozine (FZ) on a chromatographic column. After elution of Fe(III), the Fe(II) complex is recovered with water-methanol (4:1). The possibility of trace iron measurements in this complex medium by graphite-furnace atomic-absorption spectrometry has been investigated. A simplex optimization routine was required to complete the development of the analytical method.

Journal Article↗
PubMed2006

The relationship between the insulin-like growth factor-1 system and the oestrogen metabolising enzymes in breast cancer tissue and its adjacent non-cancerous tissue.

AIMS: Previous studies have shown that oestrogen and Insulin-like Growth Factor-1 (IGF-1) act synergistically and cross-stimulatory while the oestrogen receptor (ER) and IGF-1R downstream signalling pathways interact at many levels. We investigate the relationship between the ER, and IGF-1R and their ligands in a series of human breast cancer tissue and adjacent non-cancerous tissue (ANCT). METHODS: A series of 139 pairs of breast cancer tissue and ANCT were obtained and divided into ER positive and ER negative groups based on tumour ER alpha immunostaining. All samples were processed for real-time quantitative-PCR to measure IGF-1, IGF-1R, ER alpha, STS and Cyp-19 mRNA levels. In addition, ER positive MCF-7 and ER negative MDA-MB-231 cell lines were treated separately with IGF-1 and an IGF-1R inhibitor called Tyrphostin AG1024 to see the effects of stimulating and inhibiting the IGF-1R. MCF-7 cell line was also treated with 4-hydroxytamoxifen. The mRNA levels of IGF-1, IGF-1R, ER alpha, STS and Cyp-19 of treated cell lines were measured and compared to those of non-treated controls. Data generated was normalised to Cytokeratin-19 mRNA levels. RESULTS: IGF-1R expression was higher in tumour tissue compared to ANCT (P = 0.038) while IGF-1 expression was marginally higher in ANCT compared to tumour tissue only in the ER positive samples (P = 0.098). ER positive tumours had a higher expression of IGF-1 compared to ER negative tumours (P = 0.001) while IGF-1R, STS and Cyp-19 expression were higher in ER negative tumours (P = 0.000, 0.000 and 0.006 respectively). There was no difference in STS or Cyp-19 expression in tumours or ANCT. Using Spearman's Correlation test, IGF-1 positively correlated with STS, Cyp-19 and ER alpha in ER positive and negative groups (Coefficient = +0.497, +0.662 and +0.651 respectively, P = 0.000 in all). IGF-1R correlated with IGF-1, STS, Cyp-19 and ER alpha only in the ER negative tumours (Coefficient = +0.620, +0.394, +0.692 and +0.662 respectively, P = 0.000, 0.012, 0.000 and 0.000 respectively). In cell lines, IGF-1 treatment led to an increase in the mean expression of IGF-1, IGF-1R, STS and Cyp-19 in both cell lines while ER alpha expression increased only in MCF-7. IGF-1R inhibition caused a decrease in expression of all five genes in MDA-MB-231 but not in the MCF-7 cell line. Treatment with 4-hydroxytamoxifen caused a decrease in expression of all five genes. CONCLUSIONS: IGF-1R is over-expressed in malignant tissue. IGF-1 is expressed at higher levels in ER positive tumours probably as a result of oestrogen stimulation while IGF-1R expression is higher in ER negative samples as an adaptation to lower local IGF-1 levels. An IGF-1 paracrine relationship may exist between tumour and ANCT but for STS and Cyp-19, there may be an autocrine-paracrine relationship. The IGF-1 ligand-receptor system is an important regulator of oestrogen production while oestrogen may be involved in stimulating IGF-1 expression. The expression of oestrogen synthesising enzymes is higher in ER negative breast cancers which may be due to the lack of oestrogen negative feedback or contribution from the overexpression of IGF-1R.

Adult↗
PubMed1991

Isolation of DNA from blood.

A rapid, economical method of DNA isolation from blood was developed that yields DNA suitable for Southern analysis and polymerase chain reactions without organic solvent extractions. Bovine DNA was prepared from peripheral leukocytes and nuclei using pronase E digestion and ethanol precipitation. This isolation method readily adapts to multiple samples. The DNA is characterized by high yield, solubility, lack of protein contamination, and ease of restriction endonuclease digestion.

Animals↗
PubMed1992

A quantitative method for measuring the adherence of group B streptococci to murine peritoneal exudate macrophages.

We have developed a solid phase, direct binding, enzyme-linked immunosorbent assay (ELISA) to detect and quantify the adherence of group B streptococci to murine macrophages. The assay correlated well with direct microscopic quantification of adherence. As few as 3.8 x 10(4) bacteria/assay well or less than one bacterium per macrophage could be detected. This assay is both quantitative and selective, and is readily adaptable for multiple sample analysis. It provides a valuable alternative to visual detection of bacterial adherence.

Animals↗
PubMed1988

Metabolic characterization of isolated cerebral microvessels: ATP and ADP concentrations.

Isolated cerebral microvessels (ICMV) have been increasingly used to study microvascular metabolism and function. Despite this, little systematic information exists about their metabolic viability and energy status. To evaluate this, we determined the ATP content and ATP/ADP ratios of ICMV with an ultrasensitive bioluminometric assay which had been adapted for small samples. In calf cerebral microvessels, freshly isolated by a homogenization and sieving procedure, ATP content averaged 1.5 +/- 0.8 nmole/mg protein (mean +/- SE for 45 observations on 18 preparations.) The ATP/ADP ratio for these vessels was 0.96 +/- 0.4. Similar values for ATP were obtained in several preparations of ICMV from dog and rat brain. Values varied considerably in different preparations, probably due to variable degrees of damage incurred during isolation. When microvessel ATP concentrations and ATP/ADP ratios were low, they were dramatically improved by brief incubation (2 hr at 37 degrees) in an enriched tissue culture medium (Dulbecco's modification of Eagle's minimal essential medium, DMEM), or perhaps somewhat less effectively in a buffered saline solution (Earle's-Hepes) containing glucose. Boiling or incubation of microvessels with Triton X-100 lowered ATP values to less than 0.01 nmole/mg protein. The ATP content of our preparations of isolated microvessels was considerably higher than values previously reported by others using similar methods, but still less than that of cultured bovine vascular endothelial cells, even after correction for a 20% difference in intracellular water space.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1985

Tachypnoeic response to amyl nitrite inhalation in the rabbit.

Intratracheal inhalation of amyl nitrite, a non-specific smooth muscle relaxant, in the pentobarbitone/urethane anaesthetized rabbit caused reductions in tidal volume and both inspiratory and expiratory times, without a preceding apnoea, that were independent of the associated hypotension and of reflex influences from the carotid sinus region but dependent on supra-abdominal vagal integrity. In artificially ventilated, paralyzed rabbits amyl nitrite caused a pronounced sensitization of pulmonary stretch receptors (PSRs) during the inflation phase, typically with a reduction in the level of activity during the deflation phase. The time course of the change in the pattern of PSR activity paralleled that of the tachypnoeic response. The sensitization of a small sample of rapidly adapting 'irritant' receptors was of a significantly shorter duration. A unitary analysis of non-myelinated vagal afferents was not attempted. The sensitization of these vagal afferents cannot be attributed to the smooth muscle relaxant properties of amyl nitrite since other relaxants (sodium nitrite, sodium nitroprusside, phentolamine) did not possess this capacity, and such properties would be expected to diminish their activities.

Afferent Pathways↗
PubMed1991

Characterization of a hepatitis A virus strain suitable for vaccine production.

A novel isolate of hepatitis A virus, obtained from a clinical sample, has been adapted to grow on cultured human diploid cells. Growth and purification parameters have been optimized to obtain conditions suitable for the development of an inactivated vaccine. The entire viral genome was molecularly cloned, and the gene encoding the VP3 capsid protein was expressed in Escherichia coli. The resulting recombinant VP3 was used to obtain rabbit antisera which recognize the denatured protein in purified virion preparations. Nucleotide sequencing data are presented and compared to known sequences of different strains.

Amino Acid Sequence↗
PubMedDate not supplied

A comparison of behavioral interventions reported in treatment studies and programs for adults with developmental disabilities.

This study examined the frequency with which behavioral interventions reported in the research literature were being incorporated into residential treatment programs addressing identical skill deficits. A sample of 113 research articles involving 299 subjects and a corresponding sample of 299 adaptive skill programs implemented in state-funded facilities were reviewed. Information was collected about subject attributes, target behaviors, types of intervention, and alternative instructional techniques. Chi-square analyses revealed significant differences between researchers and clinicians in the categories of adaptive and maladaptive behavior targeted as well as the behavioral interventions reported. Disparities were also found in treatment implementation practices including the use of task analysis, instruction in the natural environment, teaching of replacement skills, and the functional analysis of behavior. These differences are discussed in light of federal regulations governing practices in state-funded facilities as well as current research trends.

Adult↗
PubMed2026

Research on the genome of microorganisms: ethical considerations and recommendations regarding the incidental bystander sequencing of human genetic material.

In genomic research primarily targeting microorganisms (or pathogens), a substantial risk exists that the presence of human genetic bycatch is not sufficiently recognised, and that the potential harm of unwarranted analysis, access, or sharing of human genetic bystander data is also insufficiently acknowledged or mitigated. In this Personal View, we contend that mandatory risk mitigation measures are necessary, more so in view of the likely increase of sharing of materials and pathogen sequence information under the WHO Pandemic Agreement and the related Pathogen Access and Benefit Sharing framework. Based on a joint reflection of the Institutional Review Board and individual researchers at the Institute of Tropical Medicine in Antwerp, Belgium, we propose a four-step approach to mitigate such risks: prevention or early removal of human genetic sequences, secure storage of samples and data, adaptation of informed consent, and targeted ethics review. This approach should contribute to maintaining ethical integrity, protect the rights of individuals and communities, and bolster public trust in the expanding use of untargeted sequencing in global health research.

Humans↗
PubMed1987

Flash spectroscopy of purple membrane.

Flash spectroscopy data were obtained for purple membrane fragments at pH 5, 7, and 9 for seven temperatures from 5 degrees to 35 degrees C, at the magic angle for actinic versus measuring beam polarizations, at fifteen wavelengths from 380 to 700 nm, and for about five decades of time from 1 microsecond to completion of the photocycle. Signal-to-noise ratios are as high as 500. Systematic errors involving beam geometries, light scattering, absorption flattening, photoselection, temperature fluctuations, partial dark adaptation of the sample, unwanted actinic effects, and cooperativity were eliminated, compensated for, or are shown to be irrelevant for the conclusions. Using nonlinear least squares techniques, all data at one temperature and one pH were fitted to sums of exponential decays, which is the form required if the system obeys conventional first-order kinetics. The rate constants obtained have well behaved Arrhenius plots. Analysis of the residual errors of the fitting shows that seven exponentials are required to fit the data to the accuracy of the noise level.

Bacteriorhodopsins↗
PubMed2001

Mapping 137Cs deposition: data validation methods and data interpretation.

The "Atlas of caesium deposition on Europe after the Chernobyl accident" was prepared within the framework of the Joint Study Project 6 (JSP6) of the collaborative programme on the consequences of the Chernobyl accident between the European Commission and the Ministries responsible for Chernobyl affairs in Belarus, Russia and Ukraine. The radiological data provided by scientific institutes and competent authorities of more than 30 European countries were integrated into an information platform. Data validation and intercomparison were therefore essential before the interpretation of the deposition with the help of isoline maps prepared with a geographic information system (GIS) could be done. The data validation was a two-step procedure: after performing a primary logical consistency check, other techniques based on spatial statistics were used to outline uncertain data. The purpose of this paper is to present these validation methods and to discuss the advantages and constraints of these techniques. Rather than trying to improve the techniques of spatial data analysis, suggestions are made on how an adaptation of the sampling information could improve the final result.

Cesium Radioisotopes↗