Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “compartmentalization”

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 325 records · Page 18Linked to original sources
PubMed1995

Compartmental modeling of glucagon kinetics in the conscious dog.

The aim of the present study was to examine glucagon metabolism and distribution using both compartmental-modeling approaches and steady-state organ-balance techniques in conscious, overnight-fasted dogs. Arterial plasma glucose concentrations were clamped at 14 mmol/L with a variable exogenous glucose infusion. Somatostatin was infused to block endogenous secretion of insulin and glucagon. Insulin was replaced intraportally at 2.4 pmol.kg-1.min-1 to maintain basal insulin concentrations in the range from 70 +/- 4 to 95 +/- 12 pmol/L. Glucagon was not given during the control period, but was subsequently infused peripherally in four 1-hour steps of 1.0, 3.0, 6.0, and 3.0 ng.kg-1.min-1. Glucagon levels increased from 0 to 68 +/- 6, 195 +/- 19, 378 +/- 47, and 181 +/- 20 ng/mL. Compartmental analysis of glucagon concentrations showed that glucagon was distributed in one compartment with a volume approximately equal to the plasma volume. The metabolic clearance rate of glucagon was 17.6 mL.kg-1.min-1. The liver cleared 24% of glucagon, and the kidneys, 17%.

Animals↗
PubMed1992

Distribution and disposition associated with compartmentation of body fluid in the developing fetus of the rat.

The relationship between the developmental change of the disposition kinetic character for p-phenylbenzoic acid (PPBA) and compartmentalized fluid of the body was investigated in the rat fetus. [14C]Inulin injected into the umbilical vein attained the steady state distribution at 8 min on Day 17 of gestation and at 10 min on Day 21 of gestation. Inulin space (Vi) on Day 17 of gestation was 0.686 ml/g body wt and decreased to 0.542 ml/g on Day 21 of gestation. [14C]Inulin injected into the fetuses on Days 18 and 21 of gestation remained in the fetal body. Hence a determination method of the apparent volume of distribution (Vd) for PPBA was developed using Vi. Vd on Day 17 of gestation was 0.640 ml/g body wt and decreased to 0.454 ml/g on Day 21 of gestation. Body water based on wet body weight showed no significant change. The analysis of PPBA distribution by the compartmentalization of body fluid suggests that the developmental change of Vd is reflected by that of Vi. The elimination rate (K(el)) from the fetus decreased rapidly in the earlier stages of gestation and slowly in the later stages of gestation. The change of the transplacental clearance (Cl) was mainly reflected by that of K(el) throughout the gestation period. However, the change of Vd partly influenced the change of Cl in the later stage of gestation.

Animals↗
PubMed1985

Compartmentalized immune responses: antigen-specificity of cerebrospinal fluid T-cell lines maintained in the absence of antigen.

The generation of long-term interleukin 2-dependent T-cell lines from anatomically compartmentalized sites of pathology offers a unique approach to the investigation of certain autoimmune diseases. However, it is generally believed that antigen-specific T-cell lines and clones lose antigen reactivity and specificity when propagated in the absence of antigen. Therefore, the optimal application of this approach to such diseases in which the pathogenetic antigens are unknown may be difficult. In approaching this problem, we have recently demonstrated that a proportion of antigen-specific T-cell lines derived from the peripheral circulation can maintain antigen specificity if propagated with antigen-presenting cells alone or with antigen-presenting cells together with OKT3 antibody, but in either case in the absence of antigen. In this report we describe the use of this approach to maintain the antigen specificity of T cells obtained from an anatomically compartmentalized site of pathology--the cerebrospinal fluid from a patient with tuberculous meningitis. We report here that a proportion of the T-cell lines generated from such cerebrospinal fluid lymphocytes can be maintained as antigen specific in the absence of antigen if propagated with either antigen-presenting cells alone or with antigen-presenting cells and OKT3 antibody. The approach illustrated in this report should now find broad applicability in the investigation of a number of autoimmune disease.

Antibodies, Monoclonal↗
PubMed1988

T lymphocytes compartmentalized on the epithelial surface of the lower respiratory tract express the very late activation antigen complex VLA-1.

T lymphocytes on the epithelial surface of the lower respiratory tract are thought to represent a relatively compartmentalized population of T cells that exchanges slowly with the blood. Since the lung is chronically burdened with antigens, "resident" T cells likely have a history of past activation. To evaluate this concept, we analyzed resident lung T cells for VLA-1 expression, which is indicative of a history of past stimulation. Lung lavage and blood T cells were evaluated in 13 normal nonsmokers using the monoclonal antibodies Leu4 (pan T cells), Leu3 (helper/inducer T cells), Leu2 (suppressor/cytotoxic T cells), TS2/7 (alpha 1 subunit of VLA-1), and A-1A5 (beta subunit of VLA-1) using immunofluorescence and immunoprecipitation. In contrast to normal blood T cells which did not express VLA-1, lung T cells expressed the 210-kDa alpha 1 and 130-kDa beta subunits of the VLA-1 complex, the same as blood T cells activated in culture for 3 weeks. Two-color immunofluorescence with Leu4 and TS2/7 showed that 19 +/- 6% of the lung T cells were VLA-1+, suggesting that a significant proportion of T lymphocytes on the alveolar epithelial surface are in a separate compartment from the VLA-1 blood cells. In sarcoidosis, a disease characterized by exaggerated numbers of active Leu3+ T cells in the lower respiratory tract, increased numbers of lung Leu3+ T cells expressing VLA-1 were present on the epithelial surface of the lung (P less than 0.05 compared to normals). These observations are consistent with compartmentalized, chronically stimulated T lymphocytes on the alveolar epithelial surface that exchange with the systemic immune system very slowly.

Antibodies, Monoclonal↗
PubMed1990

Propafenone kinetics in the horse. Comparative analysis of compartmental and noncompartmental models.

The propafenone kinetics after intravenous (i.v.) administration have been studied in the horse by a comparative analysis of compartmental and noncompartmental models. The pharmacokinetic parameters showed a large distribution (Vdss = 1021 +/- 211 L) and a high clearance (CI = 7019 +/- 1746 mL/min) of the drug. The plasma concentrations were very low, under 1 microgram/mL, in most cases; after 30 min these concentrations can be considered as nonefficient for the treatment of arrhythmia. There were no significant differences between pharmacokinetic parameters found with the use of compartmental and noncompartmental models.

Animals↗
PubMed1982

A method for determining nonelectrolyte uptake by adult schistosoma mansoni using compartmental analysis of hexose fluxes.

A steady-state compartmental analysis of galactose, glucose and 3-O-methylglucose fluxes was conducted on male and female Schistosoma mansoni. The method has several advantages over previously used initial rate studies. A nonlinear log-linear plot of glucose exchange is discussed in terms of differentiating between metabolized and nonmetabolized substrates in transport studies. Kt values and marker distribution volumes are estimated from the compartmental analysis and it is concluded that 3-O-methylglucose is not suited as a substrate for hexose transport studies in S. mansoni.

3-O-Methylglucose↗
PubMed1991

A system for compartmental modelling and simulation.

The paper describes a software package for modelling and simulating compartmental systems based upon a generalisation of the equations of compartmental systems. The aim is a versatile package which can be used for rapid model development. Its use is first illustrated in a number of simple classical examples. The power of the software--and more generally the methodology--is demonstrated by showing its application in developing a model-based system for insulin planning for diabetic patients. The software has been written in Pascal and runs on IBM PC and compatible computers.

Algorithms↗
PubMed1987

Fluid volumes in rainbow trout, Salmo gairdneri: application of compartmental analysis.

1. The measurement of fluid volumes by the indicator dilution technique and compartmental analysis was re-evaluated in free-swimming, undisturbed rainbow trout. 2. Plasma (33.5 ml/kg body wt) and blood (41.3 ml/kg body wt) volumes estimated by compartmental analysis from blood samples taken early (less than 5 min) after dye injection were 40% lower than volumes calculated by sampling late (greater than or equal to 80 min). 3. The rate of exchange of dye between plasma and interstitial fluid was high (48%/hr) compared to mammals (5%/hr) which supports the hypothesis that teleost capillaries have high protein permeability. 4. Total extracellular volume estimated using a single pool model (210.5 ml/kg body wt) of inulin kinetics was 20% higher than that calculated by a three pool model (172.8 ml/kg body wt).

Animals↗
PubMed1993

Tumour necrosis factor-alpha alters the blood compartmentation of amino acids in the rat.

The work presented focuses on the importance of studying the distribution of blood amino acids in both the cellular and plasmatic fraction when performing studies concerning the effects of cytokines on amino acid metabolism. Tumour necrosis factor treatment resulted in important changes in blood amino acid compartmentation between plasma and red blood cells in rats. The animals showed a change in compartmentation with an increase in the concentration of most amino acids in the cellular fraction with the exception of phenylalanine, glutamate, aspartate and tyrosine.

Amino Acids↗
PubMed1992

Metallothionein biodegradation in rat hepatoma cells: a compartmental analysis aided 35S-radiotracer study.

Disappearance rates, synthesis and biodegradation of rat HTC cell metallothioneins (MT) were examined by measurements of [35S]MT, and expressed by their rate constants in experiments carried out under steady-state conditions, with physiological doses of zinc and copper. Overall rates of disappearance of [35S]MT did not obey first-order kinetics, apparently due to the presence of chemically and/or spatially distinguishable MT (sub)pools. Application of compartmental analysis yielded results indicating that: (a) MT in copper-treated cells is stabler than MT in zinc-treated cells, (b) apparent half-lives for MT disappearance are 22-25 h under the conditions as described, (c) addition of 0.1 mM chloroquine reduces the overall rate of MT disappearance by 25%, (d) total MT should be regarded as significantly consisting of at least two MT sub-forms, i.e., Apo-MT and M-MT and/or cytosolic MT and lysosomal MT, each being depleted and replenished at different rates, (e) mean half-lives for total MT, based on actual degradation rates, were 3-7 h, (f) addition of 0.1 mM chloroquine resulted in both increased synthesis and increased degradation of non-lysosomal MT, the latter probably due to free amino acid depletion in the cells, and (g) MT behaviour may be best examined by combination of tracer experiments (35S-labeled amino acids), simultaneous determination of MT levels in all (sub)MT pools, and application of compartmental analysis.

Animals↗
PubMed1987

Intranuclear distribution of the non-histone proteins: evidence for their compartmentalization.

1. Qualitative and quantitative distribution of the non-histone proteins in nuclear matrix, chromatin, a new type of RNP-network and nucleosol of Friend cells have been investigated. 2. The specific territorial distribution and metabolism of these proteins found support for the idea of their exact compartmentalization. 3. Since the majority of the non-histone proteins belong to the protein moiety of nuclear RNP-structures their specific territorial distribution probably express a primary compartmentalization of the nuclear ribonucleoproteins.

Animals↗
PubMed1995

The compartmentation of nucleoside diphosphate kinase in mitochondria.

The compartmentation of nucleoside diphosphate kinase (NDPK) was studied in mitochondria isolated from heart and liver of rat, rabbit, and pigeon. Compartmentation was assessed by determining latencies of enzyme activities, fractionating mitochondria with digitonin, and treating mitochondria with trypsin in the presence and absence of digitonin. NDPK activity in pigeon liver mitochondria was five- and seven-fold higher than in rat and rabbit liver mitochondria. The ratios of NDPK activities in liver vs. heart mitochondria were about 15 for rat, 2 for rabbit, and more than 40 for pigeon. Nearly all NDPK in pigeon liver mitochondria is in the matrix space, but outside the matrix in rat and rabbit liver mitochondria. Most NDPK in pigeon heart mitochondria was located outside the matrix while a significant fraction may be in the matrix of rat and rabbit heart mitochondria. These results are discussed relative to the assumed role that mitochondrial NDPK transfers the phosphoryl group of GTP produced in the Krebs cycle to the adenine nucleotide pool.

Animals↗
PubMed1989

The ventral striatopallidal parts of the basal ganglia in the rat--II. Compartmentation of ventral pallidal efferents.

This paper describes the results of experiments designed to address whether neuron populations giving rise to different ventral pallidal efferent projections are segregated in a manner concordant with the recently described immunohistochemical compartmentation of ventral pallidum. The retrograde transport of horseradish peroxidase conjugated to wheatgerm agglutinin following injections in the ventral tegmental area of Tsai, medial substantia nigra and subthalamic nucleus was charted in relationship to the patterns of immunohistochemical staining in the forebrain following incubation of sections in antisera against substance P, neurotensin or leucine-enkephalin. In some cases the retrograde labeling and immunohistochemical protocols were combined in the same experiment. As a supplement, the electron microscope was utilized to investigate the ultrastructure and synaptic input of projecting cells making up populations of ventral pallidum neurons that project to different efferent targets. The results indicated that the immunocytochemical compartmentation of ventral pallidum observed in our earlier study is reflected in the organization of neurons from which ventral pallidal efferents originate. Thus, axons destined to terminate in the medial parts of substantia nigra and subthalamic nucleus project from neurons located in the lateral, neurotensin immunoreactivity-deficient part of ventral pallidum and the globus pallidus. Fibers en route to the ventral tegmental area originate in neurotensin immunoreactivity-rich medial parts of the ventral pallidum as part of a large cluster of retrogradely labeled neurons that invades several forebrain structures, including the bed nucleus of the stria terminalis, preoptic regions, and the nuclei of the diagonal band. The electron microscopic results provided additional evidence distinguishing the medial and lateral compartments of ventral pallidum. Whereas projection neurons located in both compartments display similar cytologic features, the density of synaptic input to retrogradely labeled perikarya and proximal dendrites following injections in the subthalamic nucleus is significantly greater than that seen following injections in the ventral tegmental area. Although no attempt was made to examine more distal parts of labeled dendrites in the present study, the observation that most dendritic profiles in the medial part of ventral pallidum were less contacted by boutons than their counterparts in the lateral district suggests that the level of innervation of projection neurons is generally lesser in medial ventral pallidum. This hypothesis is further supported by the presence in the medial ventral pallidum of significant numbers of "glial blockades," a cytologic configuration that is clearly capable of preventing functional interactions and is rarely observed in the lateral ventral pallidum...

Animals↗
PubMed1989

The distribution and compartmental organization of the cholinergic neurons in nucleus accumbens of the rat.

In this study the distribution of the cholinergic neurons was examined in relation to the compartmental organization of nucleus accumbens. This was accomplished by charting the location of the choline acetyltransferase-immunoreactive neurons and mapping their distribution in relation to cytoarchitectural features and the patterns of acetylcholinesterase activity and enkephalin immunoreactivity. Choline acetyltransferase-containing perikarya are inhomogeneously distributed in nucleus accumbens. Their density is lowest at the rostral pole and highest, caudomedially, at the septal pole. The cells form a compact, medial column and a diffuse, lateral zone and, moreover, there are distinct gradients in their distribution. The highest numbers of immunoreactive perikarya occur within the intensely immunostained zones of choline acetyltransferase-immunoreactive neuropil in ventral and ventromedial parts of the nucleus, whereas lower numbers coincide with choline acetyltransferase-poor zones in the central part of the nucleus. Zones of intensely choline acetyltransferase-immunoreactive neuropil are largely in register with regions of high acetylcholinesterase activity in middle and caudal parts of the nucleus but do not coincide rostrally. Choline acetyltransferase-rich zones correspond to moderate enkephalin immunoreactivity in the outer shell of the nucleus, but a moderately choline acetyltransferase-immunostained matrix surrounds "patches" of intense enkephalin immunoreactivity in the core. Small aggregates of cells, which feature commonly in nucleus accumbens, seem to be avoided by both choline acetyltransferase- and enkephalin-immunoreactive zones. Choline acetyltransferase-immunoreactive processes are mostly confined by the boundaries of their respective immunoreactive zones. Few choline acetyltransferase-immunoreactive neurons lie in the enkephalin-rich patches and those that lie close to the patches show little preference in the directionality of their processes such that some cross the borders, whereas others do not. Thus, our findings show that the cholinergic elements are differentially distributed within nucleus accumbens; that these elements are compartmentally ordered; and that, in light of their limited access to other compartments, they possibly play only a minor role in intercompartmental communication.

Animals↗
PubMed1996

Differential compartmentalization of vasopressin messenger RNA and neuropeptide within the rat hypothalamo-neurohypophysial axonal tracts: light and electron microscopic evidence.

Arginine vasopressin messenger RNA is axonally transported in the rat hypothalamo-neurohypophysial system [for review see Mohr et al. (1993) In Vasopressin (eds Gross P., Richter D. and Robertson C. L.), pp. 119-129, John Libbey Eurotext]. Upon chronic dehydration (2% saline-feeding for seven days), vasopressin messenger RNA within this axonal compartment is dramatically increased and appears aggregated in a selected subset of axonal swellings confined to the median eminence and posterior pituitary. In this study, we analysed the axonal distribution of the vasopressin messenger RNA within the hypothalamo-neurohypophysial tracts of control and saline-fed animals, and compared this distribution to that of the vasopressin peptide. Our data further support a selective aggregation of the vasopressin messenger RNA in a subset of distal axonal swellings and/or terminals of the median eminence and posterior pituitary. The selective aggregation is observed not only in saline-fed animals, but also in control animals. Although the osmotic stimulus dramatically enhances the axonal transport of vasopressin messenger RNA, the consequent general distribution pattern of the messenger RNA in the hypothalamo-neurohypophysial system is not changed. However, the physiological perturbation does increase the number of vasopressin messenger RNA-containing swellings within the median eminence and the posterior pituitary. In both saline-fed and control animals, the level of messenger RNA label within individual swellings appeared roughly similar to that found in the perikaryal cytoplasm of extra-hypothalamic vasopressinergic neurons. A detailed comparison of the axonal compartmentalization of vasopressin messenger RNA and vasopressin peptide demonstrates that the axonal distribution of vasopressin messenger RNA does not precisely overlap that of vasopressin peptide along the hypothalamo-neurohypophysial tract. In seven-day saline-fed animals, the majority of the messenger RNA-containing swellings of the median eminence also contain detectable vasopressin peptide; however in the same animals, nearly all the messenger RNA-containing swellings of the posterior pituitary appear devoid of vasopressin peptide. Therefore, our work strongly suggests that at least in the posterior pituitary, the vasopressin messenger RNA might be selectively targeted and aggregated in a selected subset of axonal swellings containing little if any vasopressin, and hence very few neurosecretory granules. Given this evidence that vasopressin messenger RNA and neuropeptide are differentially compartmentalized in axons of magnocellular neurons, we propose that vasopressin messenger RNA and peptide probably rely on different intracellular transport systems with respect to packaging, transport and/or aggregation within these selected axonal locations.

Animals↗
PubMed1991

The isopycnic, compartmentalized integration of Rous sarcoma virus sequences.

Rous sarcoma virus (RSV) can cause tumors in hamsters, which harbor complete or partially deleted RSV sequences, in their genomes. Here we have studied the localization of RSV sequences integrated into the genome of cell lines derived from six independent hamster tumors. We have found that integration occurred in the isochores richest in guanine + cytosine, of the host genome, as it had been previously observed for bovine leukemia and hepatitis B viral sequences. The integration of RSV proviral sequences is, therefore, 'isopycnic' (i.e., it takes place in host genome sequences which compositionally match the viral sequences) and compartmentalized (i.e., it occurs in a small compositional compartment of the host genome). The hamster genome compartment hosting RSV sequences precisely corresponds to a compartment of the human genome which is the most active in both transcription and recombination. The notion of a compartmentalized, isopycnic integration of RSV proviral sequences fits, therefore, with the viral integration into transcriptionally active and recombinogenic regions of the host genome observed by other authors, but is broader, in that it includes, in addition, the requirement for a compositional match between host genome sequences and expressed viral sequences.

Animals↗
PubMed1992

Beauty and the yeast: compartmental organization of the secretory pathway.

Our perception of intracellular organelles and cellular architecture was initially based on striking light and electron micrographs of animal and plant cells. The high degree of compartmental organization within specialized mammalian secretory cells aided early efforts to track the movement of proteins through the organelles of the secretory pathway. In contrast, the morphological detail of the yeast Saccharomyces cerevisiae appeared superficially simple, even primitive, by comparison with the higher eukaryotic cells. However, the combination of genetic tools and the development of assays reconstituting vesicular traffic in yeast have facilitated the identification and characterization of individual proteins that function in the secretory pathway. Analogies between the function of yeast and mammalian proteins in vesicular traffic are being drawn with increasing frequency. In this review, the combination of genetic, biochemical, molecular and cell biological approaches used to study compartmental organization in the yeast secretory pathway will be discussed. The rapid progress in our understanding of yeast membrane traffic has revealed the beauty of working with this organism.

Animals↗
PubMed2004

In vitro compartmentalization by double emulsions: sorting and gene enrichment by fluorescence activated cell sorting.

Water-in-oil (w/o) emulsions can be used to compartmentalize and select large gene libraries for a predetermined function. The aqueous droplets of the w/o emulsion function as cell-like compartments in each of which a single gene is transcribed and translated to give multiple copies of the protein (e.g., an enzyme) it encodes. While compartmentalization ensures that the gene, the protein it encodes, and the products of the activity of this protein remain linked, it does not directly afford a way of selecting for the desired activity. Here we show that re-emulsification of w/o emulsions gives water-in-oil-in-water (w/o/w) emulsions with an external (continuous) water phase through which droplets containing fluorescent markers can be isolated by fluorescence-activated cell sorting (FACS). These w/o/w emulsions can be sorted by FACS, while the content of the aqueous droplets of the primary w/o emulsion remains intact. Consequently, genes embedded in these water droplets together with a fluorescent marker can be isolated and enriched from an excess of genes embedded in water droplets without a fluorescent marker. The ability of FACS instruments to sort up to 40000 events per second may endow this technology a wide potential in the area of high-throughput screening and the directed evolution of enzymes.

DNA Modification Methylases↗