Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Intermediate Variables”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed1984

Biochemical markers in non-Hodgkin's lymphoma stages III and IV and prognosis: a multivariate analysis.

The prognostic value of different pretreatment laboratory and clinical findings at diagnosis was assessed in a series of 141 patients with generalized non-Hodgkin's lymphoma. Univariate and multivariate survival analysis (Cox's regression model) was performed, using serum analysis of deoxythymidine kinase (S-TK), beta 2-microglobulin, lactic dehydrogenase, alpha 1-acid glycoprotein = orosomucoid (S-alpha 1 AGP), haptoglobin and ferritin. In addition, Hb and the erythrocyte sedimentation rate (ESR) were measured. The clinical variables were age, presence or absence of B-symptoms, histopathology ('low-grade'; 'intermediate grade' and 'high-grade' malignancy) and bone marrow involvement. Of the 8 biochemical markers, all except Hb and the ESR showed a significant relationship to survival. Among the clinical variables, this finding was made for B-symptoms and histopathology. Using a multivariate analysis on all variables, S-TK was found to be the best factor for predicting duration of survival. The only significant additional information was provided by S-alpha 1 AGP. When only the clinical variables were taken into account, it was found that histopathology added significant information to that yielded by B-symptoms in the prediction of the survival time. When the biochemical variables were added to this model, only S-TK was of significant additional prognostic value.

Adolescent↗
PubMed1971

Compound stimulus control by discriminative stimuli associated with high and moderate response rates.

Four rats received water on a fixed-ratio schedule for lever pressing in the presence of a tone (or light) stimulus and on a variable-interval schedule in the presence of a light (or tone) stimulus. Following stabilization of a high response rate during the fixed-ratio component and a moderate response rate during the variable-interval component, brief periods with the light and tone presented simultaneously but with no responses reinforced were inserted into the regular training schedule. Response rates during the compound stimuli were intermediate between the response rates controlled by the individual fixed-ratio and variable-interval associated stimuli.

Animals↗
PubMed1995

Neuromuscular control and kinematics of intermittent flight in the European starling (Sturnus vulgaris)

Electromyographic (EMG) and kinematic data were collected from European starlings (Sturnus vulgaris) flying at a range of speeds from 8 to 18 m s-1 in a variable-speed windtunnel. Their flight at all speeds consisted of alternating flapping and non-flapping phases. Wing postures during non-flapping phases included glides, partial-bounds and bounds. Glides were performed proportionally more often within each speed and were longer in duration than either of the other two non-flapping postures, but the percentage of bounds increased markedly with increasing flight speed. The shift from flap-gliding at slow speeds towards flap-bounding at fast speeds was consistent with reducing mean power output relative to continuous flapping. The starlings often combined more than one non-flapping posture within a single non-flapping period. Transitions between non-flapping postures, as well as transitions between bounds and subsequent flapping, were classified as 'pull-outs'. Pull-outs consisted of an increase in wingspan but no change in wingtip elevation. The pectoralis and supracoracoideus exhibited electrical activity during glides but not during bounds. The scapulohumeralis caudalis was not active during glides, but this muscle and the supracoracoideus were typically active during partial-bounds and pull-out phases. The scapulohumeralis caudalis occasionally showed activity during bounds, which may reflect its role as a humeral retractor. The frequency and duration of non-flapping intervals in starlings were less during EMG experiments than during non-implanted flights. During flapping phases, relative intensity and duration of EMG signal and wingbeat frequency increased with flight speed, whereas flapping or non-flapping cycle duration, the percentage of a cycle spent flapping and the number of wingbeats in a cycle were all greatest at 8 m s-1. Wingbeat amplitude was smaller at intermediate speeds, but differences among speeds were not significant. These variables allowed indirect estimates of power output and suggested that minimum power speed for starlings was near 12 m s-1 and that power output increased at both slower and faster speeds. Within windtunnel speeds, muscle activity changed in relation to wingspan at mid-upstroke, wingtip excursion, wingbeat frequency, acceleration, velocity, altitude and horizontal position.

Journal Article↗
PubMed1987

Thyroid, lipid and other biological variables in elderly patients with asymptomatic autoimmune thyroiditis: a statistical analysis.

Asymptomatic autoimmune thyroiditis (AAT), especially prevalent in elderly women and associated with the presence of thyroid antibodies (HT), is recognized as a precursor of hypothyroidism and is an intermediate between euthyroidism and hypothyroidism. This paper is concerned with the possible modifications of biochemical variables - some of which are not directly related to the thyroid - in patients with AAT. Thirty-seven serum factors were investigated in euthyroid, AAT, and HT subjects over 69 years of age. They were thyroglobulin; microsomal, gastric and adrenal antibodies; LE cells, and thyroid, lipid and immunological variables linked to the inflammatory process. In women the only variable, other than those related to the thyroid, which showed any modification in the AAT state was the cholesterol level. Wholly different observations were made in men, stressing the necessity of separate analysis of male and female data: the thyroid-related variables which were modified in the AAT state are not the same as in women, the cholesterol is not increased but triglycerides, HDL, albumin and inflammatory variables are modified. Furthermore, the lipid variables showed an unexpected age dependency in AAT, but not in euthyroid women (between 69-90 years of age).

Aged↗
PubMed1991

Fats in seasoning and breast cancer risk: an Italian case-control study.

The relationship between consumption of fat in seasoning and risk of breast cancer was considered in a case-control study conducted in northern Italy of 2663 cases of breast cancer and 2344 controls admitted in the same network of hospitals with acute, non-neoplastic and non-gynaecological conditions. Subjective scores corresponding to three levels (low, intermediate and high) of intake of butter, margarine and oil, together with a combined variable of these three items ("total fat"), were used to evaluate the personal use of fat in seasoning. Compared to low use, a slight but significant increase in risk was observed for intermediate and high intake of butter, oil and total fat with relative risks of 1.5 (95% confidence interval [CI], 1.1-1.9) for high intake of butter, 1.3 (95% CI, 1.0-1.6) for high intake of oil and 1.4 (95% CI, 1.2-1.7) for high intake of total seasoning fat. These results were not materially modified after allowance for a number of identified potentially distorting factors. The results of this study suggest that there is a positive association, although moderate, between breast cancer risk and intake of fat added in seasoning, which may represent an indirect indicator of the subject's attitude towards fat.

Adult↗
PubMed1992

Toward a definition of asthma for epidemiology.

Because there is no "gold standard" for defining asthma for epidemiology, we have defined current asthma as bronchial hyperresponsiveness (BHR) plus recent wheeze (in the 12 months prior to study). To describe the characteristics of groups categorized by these measurements, we studied two samples of children aged 7 to 12 yr: 210 from a population sample and 142 self-identified asthmatics. Bronchial responsiveness to histamine was measured by the rapid method, respiratory symptom history, and asthma medication use by self-administered questionnaire to parents and atopy by skin prick tests to 14 allergens. Children recorded daily Airflometer readings and symptom scores for 2 wk. Children with current asthma had more severe bronchial responsiveness, greater Airflometer variability, more symptoms, more atopy (particularly to house dust mites), and used more asthma medication than children with BHR or recent wheeze alone. Children with BHR, but not with recent wheeze, were intermediate between the current asthma and normal groups in terms of bronchial responsiveness, Airflometer variability, and atopy. Children with recent wheeze and normal responsiveness differed from the normal group only in symptoms and medication use. Our definition of current asthma discriminates a group of children that is clearly different in terms of both clinical features and physiologic measures. As such, it is the most useful definition to date for measuring the prevalence of clinically important asthma in populations.

Asthma↗
PubMed1985

Dynamic histology of the antral epithelium in the mouse stomach: I. Architecture of antral units.

The architecture of the pure mucous units of the pyloric antrum was investigated in 3- to 4-month-old CD1 mice. Units were serially cut in cross section and stained by a method combining the periodic acid-Schiff sequence, a modified Grimelius's silver nitrate procedure, and Regaud's hematoxylin. A total of 195 units were then reconstructed. Of these, six were cast in polyester resin and 189 were two-dimensionally reproduced on graph paper. The reconstructions showed antral units to be divided among three main classes. The first class, which contained 32% of the units, consisted of fingerlike tubules referred to as "singlets." Three types of singlets were observed. The first or type A, which represented 76% of the singlets, was divisible into three successive portions: a pit (foveola) opening onto the mucosal surface and lined by mucous cells referred to as pit cells, an isthmus continuous with the pit and containing immature proliferative mucous cells, and a gland forming the blind end of the tubule and lined by mucous cells referred to as gland cells. Type B (14% of singlets) was similar to type A except that its gland was forked. Type C (10% of singlets) differed by the absence of a gland. The units of the second class, which contained 53% of the total number, were joined together along part of their length and were named "multiplets." Most of them (90%) were organized into clusters of two, and 10% into clusters of three. In the joined portion, the epithelial cells of the adjacent units were in contact through junctional complexes and, therefore, were not separated by basement membranes. Otherwise the units showed the same component parts as in singlets. Also, as in singlets, the majority of the units were type A and a few were type B or C. The units of the third class, or "intermediates," consisted of tubules which exhibited a branching process. This process was of variable length but could include gland, isthmus, and sometimes pit. Thus, the process duplicated a varying proportion of the unit. In conclusion, the pure mucous units of the antrum exhibit various patterns which have been designated singlet, multiplet, or intermediate. It is proposed that these three patterns are related and represent temporal differences in the duplication and production of new units. Based on this assumption, a model has been elaborated to depict the likely sequence in the proliferation of pure mucous units. It is proposed that this proliferation takes place in the antrum of young adult mice.

Animals↗
PubMed2004

Assessing the use of delta(13)C natural abundance in separation of root and microbial respiration in a Danish beech (Fagus sylvatica L.) forest.

Our understanding of forest biosphere-atmosphere interactions is fundamental for predicting forest ecosystem responses to climatic changes. Currently, however, our knowledge is incomplete partly due to inability to separate the major components of soil CO(2) effluxes, viz. root respiration, microbial decomposition of soil organic matter and microbial decomposition of litter material. In this study we examined whether the delta(13)C characteristics of solid organic matter and respired CO(2) from different soil-C components and root respiration in a Danish beech forest were useful to provide information on the root respiration contribution to total CO(2) effluxes. The delta(13)C isotopic analyses of CO(2) were performed using a FinniganMAT Delta(PLUS) isotope-ratio mass spectrometer coupled in continuous flow mode to a trace gas preparation-concentration unit (PreCon). Gas samples in 2-mL crimp seal vials were analysed in a fully automatic mode with an experimental standard error +/-0.11 per thousand. We observed that the CO(2) derived from root-free mineral soil horizons (A, B(W)) was more enriched in (13)C (delta(13)C range -21.6 to -21.2 per thousand ) compared with CO(2) derived from root-free humus layers (delta(13)C range -23.6 to -23.4 per thousand ). The CO(2) evolved from root respiration in isolated young beech plants revealed a value intermediate between those for the soil humus and mineral horizons, delta(13)C(root) = -22.2 per thousand, but was associated with great variability (SE +/- 1.0 per thousand ) due to plant-specific differences. delta(13)C of CO(2) from in situ below-ground respiration averaged -22.8 per thousand, intermediate between the values for the humus layer and root respiration, but variability was great (SE +/- 0.4 per thousand ) due to pronounced spatial patterns. Overall, we were unable to statistically separate the CO(2) of root respiration vs. soil organic matter decomposition based solely on delta(13)C signatures, yet the trend in the data suggests that root respiration contributed approximately 43% to total respiration. The vertical gradient in delta(13)C, however, might be a useful tool in partitioning respiration in different soil layers. The experiment also showed an unexpected (13)C-enrichment of CO(2) (>3.5 per thousand ) compared with the total-C signatures in the individual soil-C components. This may suggest that analyses of bulk samples are not representative for the C-pools actively undergoing decomposition.

Biomass↗
PubMed1999

Telomere shortening, telomerase expression, and chromosome instability in rat hepatic epithelial stem-like cells.

Telomeres, which are specialized structures consisting of T2AG3 repeats and proteins at the ends of chromosomes, may be essential for genomic stability. To test whether telomere length maintenance preserves genomic stability in rats (Rattus rattus and Fischer 344), we assayed telomerase activity and telomere length in the rat hepatic epithelial stem-like cell line WB-F344 during aging in vitro and in tumor-derived lines. Telomerase activity in the parental WB-F344 line was repressed at low and intermediate passage levels in vitro and reexpressed at high passages. Southern blot hybridization and quantitative fluorescence in situ hybridization analyses demonstrated that telomeres were significantly eroded at intermediate passage levels, when telomerase was repressed, and at high passage levels, when telomerase was expressed. Fluorescence in situ hybridization analysis also revealed interstitial telomeric sequences in rat chromosomes. Tumor-derived WB-F344 cell lines that express telomerase had variably shortened telomeres. Cytogenetic analyses performed on WB-F344 cells at low, intermediate, and high passages demonstrated that chromosome instability was most severe in the intermediate passage cells. These data suggest that telomere shortening during aging of rat hepatic epithelial stem-like WB-F344 cells in vitro and during selection of tumorigenic lines in vivo may destabilize chromosomes. Expression of telomerase in high passage cells appeared to partially stabilize chromosomes.

Animals↗
PubMed2007

Impact of modelling intra-subject variability on tests based on non-linear mixed-effects models in cross-over pharmacokinetic trials with application to the interaction of tenofovir on atazanavir in HIV patients.

We evaluated the impact of modelling intra-subject variability on the likelihood ratio test (LRT) and the Wald test based on non-linear mixed effects models in pharmacokinetic interaction and bioequivalence cross-over trials. These tests were previously found to achieve a good power but an inflated type I error when intra-subject variability was not taken into account. Trials were simulated under H0 and several H1 and analysed with the NLME function. Different configurations of the number of subjects n and of the number of samples per subject J were evaluated for pharmacokinetic interaction and bioequivalence trials. Assuming intra-subject variability in the model dramatically improved the type I error of both interaction tests. For the Wald test, the type I error decreased from 22, 14 and 7.7 per cent for the original (n = 12, J = 10), intermediate (n = 24, J = 5) and sparse (n = 40, J = 3) designs, respectively, down to 7.5, 6.4 and 3.5 per cent when intra-subject variability was modelled. The LRT achieved very similar results. This improvement seemed mostly due to a better estimation of the standard error of the treatment effect. For J = 10, the type I error was found to be closer to 5 per cent when n increased when modelling intra-subject variability. Power was satisfactory for both tests. For bioequivalence trials, the type I error of the Wald test was 6.4, 5.7 and 4.2 per cent for the original, intermediate and sparse designs, respectively, when modelling intra-subject variability. We applied the Wald test to the pharmacokinetic interaction of tenofovir on atazanavir, a novel protease inhibitor. A significant decrease of the area under the curve of atazanavir was found when patients received tenofovir.

Adenine↗
PubMed1992

Specific types of prosomes are associated to subnetworks of the intermediate filaments in PtK1 cells.

Prosomes are small ribonucleoprotein (RNP) particles of unique morphology in the electron microscope but of variable protein and RNA composition, depending on the differentiation state of the cells studied. They were initially observed as subcomplexes of untranslated mRNP. In previous studies, we found that prosomes are associated to the intermediate filaments (IF) of cytokeratin type in HeLa and PtK1 cells. Here we have studied in detail the association of prosomal antigens with the IF networks in PtK1 cells. Contrary to our earlier conclusions, in these cells the vimentin fibers also carry prosomes which, thus, distribute in between the two types of networks. During the selective collapse of the IF induced by acrylamide, and upon recovery after the withdrawal of the drug, no dissociation of the prosome and IF networks of cytokeratin- and vimentin-type could be observed. These data show that even in a dynamic situation, prosome and IF antigens do not dissociate, indicating strongly that they are located on one and the same structure. Furthermore, the differential distribution of specific prosomal antigens between both types of intermediate filament networks indicates that prosomes do not ubiquitously populate the intermediate filaments but occupy subnetworks of either vimentin or cytokeratin type.

Acrylamide↗
PubMed2001

Costimulatory molecules in human periodontal disease tissues.

An immunoperoxidase technique was used to examine CD28, CD152, CD80 and CD86 positive cells in gingival biopsies from 21 healthy/gingivitis and 26 periodontitis subjects. The samples were placed into 3 groups (small, intermediate, large) according to the size of the infiltrate. The percent CD28+ T cells in the connective tissue infiltrates was highly variable with no differences between the healthy/gingivitis and periodontitis groups. While there was an increase in positive cells in intermediate infiltrates from both healthy/gingivitis (28.5%) and periodontitis (21.4%) patients compared with small infiltrates (8.6% and 11.8%, respectively), this was not significant, although the percent CD28+ T cells did increase significantly in tissues with increased proportions of B cells relative to T cells (p=0.047). A mean of less than 5% infiltrating T cells were CD152+ which was significantly lower than the mean percent CD28+ T cells in intermediate healthy/gingivitis lesions (p = 0.021). The mean percent CD80+ and CD86+ B cells and macrophages was 1-7% and 8-16%, respectively, the difference being significant in intermediate healthy/gingivitis tissues (p = 0.012). Analysis of these cells in relation to increasing numbers of B cells in proportion to T cells and also to macrophages, suggested that CD80 was expressed predominantly by macrophages while CD86 was expressed by both macrophages and B cells. Few endothelial cells expressed CD80 or CD86. Keratinocytes displayed cytoplasmic staining of CD80 rather than CD86 although the numbers of positive specimens in the healthy/gingivitis and periodontitis groups reduced with increasing inflammation. In conclusion, percentages of CD28, CD152, CD80 and CD86 did not reflect differences in clinical status. However, the percent CD28+ T cells increased with increasing size of infiltrate and with increasing proportions of B cells suggesting increased T/B cell interactions with increasing inflammation. The percent CD152+ cells remained low indicating that CD152 may not be involved in negative regulation of T cells in periodontal disease. CD80 and CD86 have been reported to promote Th1 and Th2 responses, respectively, and the higher percent CD86+ cells suggests a predominance of Th2 responses in both healthy/gingivitis and periodontitis tissues. Nevertheless, other factors including cytokines themselves and chemokines which modulate T cell cytokine profiles must be monitored to determine the nature of Th1/Th2 responses in periodontal disease.

Abatacept↗
PubMed2001

Gene duplication and the evolution of group II chaperonins: implications for structure and function.

Chaperonins are multisubunit protein-folding assemblies. They are composed of two distinct structural classes, which also have a characteristic phylogenetic distribution. Group I chaperonins (called GroEL/cpn60/hsp60) are present in Bacteria and eukaryotic organelles while group II chaperonins are found in Archaea (called the thermosome or TF55) and the cytoplasm of eukaryotes (called CCT or TriC). Gene duplication has been an important force in the evolution of group II chaperonins: Archaea possess one, two, or three homologous chaperonin subunit-encoding genes, and eight distinct CCT gene families (paralogs) have been described in eukaryotes. Phylogenetic analyses indicate that while the duplications in archaeal chaperonin genes have occurred numerous times independently in a lineage-specific fashion, the eight different CCT subunits found in eukaryotes are the products of duplications that occurred early and very likely only once in the evolution of the eukaryotic nuclear genome. Analyses of CCT sequences from diverse eukaryotic species reveal that each of the CCT subunits possesses a suite of invariant subunit-specific amino acid residues ("signatures"). When mapped onto the crystal structure of the archaeal chaperonin from Thermoplasma acidophilum, these signatures are located in the apical, intermediate, and equatorial domains. Regions that were found to be variable in length and/or amino acid sequence were localized primarily to the exterior of the molecule and, significantly, to the extreme tip of the apical domain (the "helical protrusion"). In light of recent biochemical and electron microscopic data describing specific CCT-substrate interactions, our results have implications for the evolution of subunit-specific functions in CCT.

Animals↗
PubMed1980

The fine structure of smooth muscle cells and their relationship to connective tissue in the rabbit portal vein.

The smooth muscle of rabbit portal vein was studied by electron microscopy with particular emphasis on the mechanical linkage between the muscle cells and on the distribution of connective tissue. The media of this vein is composed of inner circular and outer longitudinal muscle layers which are orientated almost perpendicularly to each other. The muscle of the inner circular layer shows very irregular contours with much branching and anastomosing of the cytoplasmic processes, which often make membrane contacts with neighbouring cells to form an extensive network of cytoplasmic processes. The muscle cells of the outer longitudinal layer are arranged in densely packed bundles and are spindle-shaped, with no branching processes. Opposing dense areas from neighbouring cells, with variable gap distances (30--100 nm) and close membrane contacts (intermediate junctions) with a gap of 11 nm were observed in both circular and longitudinal muscle layers. In the terminal regions of muscle cells in both circular and longitudinal layers a specialized anchoring structure was present which was closely related to extracellular elastic tissue. Muscle cells in the longitudinal layer showed the most elaborate structure, the tapering end of the muscle cell showing a honeycomb-like structure penetrated by columns of connective tissue compounds. The functional implications of these structures are discussed.

Animals↗
PubMed1989

Carcinosarcoma of the urinary bladder. A light, immunohistochemical and electron microscopical case report.

A case of urinary bladder carcinosarcoma (UBCS) is reported with light, immunohistochemical and electron microscopical findings. The tumour consisted of a squamous cell carcinoma, variable spindle cell stromal elements compatible with fibrosarcoma, and rhabdomyoblasts. Intermediate filament co-expression of cytokeratin and vimentin was shown by immunohistochemistry. Electron microscopy (EM) confirmed the nature of the three components, and indicated some similarities between the three cell-types present. Comparisons with the previous UBCS in the literature are made.

Aged↗
PubMed1984

Complex carbohydrates in the secretory epithelium of the goat prostate.

The complex carbohydrates in the epithelium of the goat prostate were studied with a battery of light microscopical histochemical methods that included peroxidase-labelled lectin-diaminobenzidine (PO-LT-DAB) procedures. The secretory epithelial cells were found to be of three types: (a) mucus-producing cells, (b) protein-secreting cells, and (c) cells intermediate between (a) and (b). All these cell types contained variable amounts of neutral and acidic complex carbohydrates. The histophysiological significances of these substances in the glandular cells are discussed with special reference to the function of the accessory sex glands.

3,3'-Diaminobenzidine↗
PubMed1998

Tonotopic organization of auditory receptors of the bushcricket pholidoptera griseoaptera (Tettigoniidae, decticinae)

The peripheral and central tonotopy of auditory receptors of the bushcricket Pholidoptera griseoaptera is described. Out of 24 auditory receptor cells of the crista acustica 18 were identified by single-cell recordings in the prothoracic ganglion and complete staining with neurobiotin. Proximal receptor cells of the crista acustica were most sensitive to 6 kHz, with medial cells being sensitive to 20-30 kHz, whereas distal cells were most sensitive to frequencies higher than 50 kHz. Projection areas within the auditory neuropile in the prothoracic ganglion were to- notopically arranged. Proximal cells projected anteriorly, medial cells ventrally and posteriorly, and distal cells to more dorsal regions. Identified receptor cells revealed an interindividual variability of tuning and central projections. Receptor cells from the intermediate organ of a bushcricket were identified for the first time. Receptors of the distal intermediate organ were broadly tuned and less sensitive than those of the crista acustica. Receptor cells of the proximal intermediate organ were most sensitive to frequencies below 10 kHz. They projected in anterior portions of the auditory neuropile, whereas cells of the distal intermediate organ had terminations spread over almost the whole auditory neuropile.

Journal Article↗
PubMed1986

Pharmacological profile of tazasubrate, a new cholesterol-lowering agent.

The properties of tazasubrate (2-phenyl-2-[(6-ethoxy-2-benzothiazolyl)thio]propionic acid), a potent hypocholesterolemic agent, were studied in rats. Tazasubrate was found to be a reliable and highly effective hypocholesterolemic agent. There was a marked and reproducible reduction of serum cholesterol in various rat models differing in age, sex and diet, an improvement of the pathological lipoprotein pattern, slight but variable effects on serum triglycerides and phospholipids, no accumulation of intermediates of cholesterol biosynthesis, no inhibition of phospholipid metabolism (i.e. no induction of phospholipidosis), no interaction with the thyroid gland, and in contrast to fibrates, only minimal induction of peroxisomes in hepatocytes.

Animals↗