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At least 91 records · Page 5Linked to original sources

PubMed1979

PTC-tasting ability in populations living in Kirghizia with special reference to hypersensitivity: its relation to sex and age.

The dimorphism in sensitivity to PTC, with a dilution scale up to 29, was studied in 320 male and 320 female Kirghiz students, 45 male and 200 female Russian students in Frunze, and in 734 Kirghiz schoolchildren in a high-altitude area of South Kirghizia. Gene t frequency was 0.44 for the Kirghiz students, 0.56 for the Russian students, and 0.54 for the Kirghiz schoolchildren. In all the groups studied it was established that such factors as sex and age have no modifying effect on sensitivity to PTC and the pattern of the distribution of sensitivity. In all the groups the frequency of 'tasters' exceeded that of 'nontasters.' Among the Kirghiz students there was a very small percentage (1.2%) of hypersensitive subjects (dil. No. 18), while 14.1% of the Kirghiz children of one Kyzyl-Dzhar school were hypersensitive. Genealogical studies showed that all the hypersensitive subjects belonged to one small stock and lived in the same village. Family studies of probands suggest the existence of a new (third) allele (T2) which determines hypersensitivity to PTC.

Adolescent↗

PubMed1991

The labeling of lipoproteins for studies of cellular binding with a fluorescent lipophilic dye.

N,N-dipentadecylaminostyrylpyridinium iodide is a dye that is approximately 100-fold more intensely fluorescent in a lipid than aqueous environment. This observation suggests its potential as a fluorescence stain for lipoproteins. This work reports the staining of LDL with this dye for use in studies of cellular binding. The staining procedure is simple, resulting in stable attachment of the dye as determined by transfer experiments, physical properties essentially identical to native LDL as demonstrated by virtually identical electrophoretic mobility, and consistent results in studies of cellular binding using flow cytometry. Increased signal to noise ratio over other dyes used for lipoprotein staining including the widely used Dil (3,3'-dioctadecylindocarbocyanine iodide) allows determinations of greater sensitivity and precision to be made. This is demonstrated by the flow cytometric determination of the 4 degrees C binding curve of LDL with freshly isolated human peripheral blood lymphocytes (i.e., cells not LDL receptor upregulated). Mediation of binding by the LDL receptor is demonstrated by correspondence between the LDL receptor dissociation constant derived from this work and literature values; increased specific binding in lymphocytes cultured in lipoprotein-deficient media to up-regulate the LDL receptor; and decreased specific binding in lymphocytes cultured in the presence of 25-hydroxy cholesterol for 48 h to suppress the LDL receptor.

Flow Cytometry↗

PubMed1991

Isolation and properties in culture of human adrenal capillary endothelial cells.

The isolation of human adrenal capillary endothelial (HACE) cells without resort to fluorescence activated cell sorting is described, together with their properties in culture. HACE cells were isolated by plating collagenase digests at high dilution in the presence of endothelial cell growth supplement, followed by clonal selection of endothelial colonies. HACE cells exhibit a typical endothelial 'cobblestone' morphology at confluence and formed 'tubes' when seeded onto 'Matrigel'. They are positive for human MHC1, and the endothelial markers ENDOCAM (CD31) and weakly CD34, they also take up dil-acetyl low density lipoprotein but are negative for Factor VIII. Their growth is strongly stimulated by FGF and inhibited by TGF-beta I. Like their much studied bovine counterparts they are robust in culture, retaining the properties described up to senescence. HACE cells provide a readily available alternative to human umbilical vein endothelial cells in that they are easily isolated pure and in quantity. They should be particularly useful in studies where human capillary, as opposed to large vessel endothelium, is required.

Adrenal Glands↗

PubMed1991

Isolation and characterization of an established endothelial cell line from transgenic mouse hemangiomas.

A murine endothelial cell line was isolated from hemangiomas induced by expression of the polyoma early region gene in transgenic mice. After two cell sortings using acetylated low-density lipoprotein with a fluorescent label (Dil-Ac-LDL), a pure population of endothelial cells has been carried for more than 60 passages from the animal. The cells retain endothelial cell properties such as a characteristic cobblestone appearance at confluency, contact-inhibited growth, and active uptake of Ac-LDL. Expression analysis shows that the cells express both the polyoma transgene and the von Willebrand factor, an endothelial cell marker. Subcutaneous injection of the cultured endothelial cells into nontransgenic histocompatible mice or nude mice led to hemangioma formation, and endothelial cells were re-isolated by cell sorting from these secondary hemangiomas. This cell line represents a renewable source of murine endothelial cells derived from transgenic mice that can be studied both in vitro and by reintroduction into a host.

Animals↗

PubMed1992

Effects of atrial natriuretic peptide and toad heart extract on isolated toad Bufo arenarum aortic rings.

The vascular effects of synthetic atrial natriuretic peptide (ANP) (rANP-99-126), and toad heart extract (THE) were examined on isolated toad aortic rings from the toad Bufo arenarum. ANP inhibited contraction produced by human angiotensin II (AT II), norepinephrine (NE), and arginine vasopressin (AVP) in isolated toad aortic rings. The present data show that a relaxant effect of ANP could be obtained also in the noncontracted aortic smooth muscle of toad if it had been previously challenged with AT II or NE and allowed to return to the original basal tension. Bufo arenarum THE was able to relax the AT II-induced contraction in toad aortic rings. In toad arteries contracted with 10(-6) M AT II, ANP produced a dose-dependent relaxation with a half-maximal inhibitory concentration IC50 of 1.2 x 10(-8) M. ANP was not effective in relaxing contraction induced by high K+. The vasorelaxant effect of ANP on AT II-induced contraction was significantly increased in Ca(2+)-free medium containing 3 mM ethylene glycol bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA-Ringer) or by pretreatment with the calcium antagonist, diltiazem (DIL). The vasorelaxant effect of ANP on basal tension after treatment with AT II was also obtained in absence of extracellular calcium (EGTA-Ringer). These results show that Bufo arenarum contains ANP-like material and that the ANP relaxant action in the toad aorta is similar to that in mammals.

Angiotensin II↗

PubMed1987

Increased uptake of monocyte-treated low density lipoproteins by aortic endothelium in vivo.

A new technique was elaborated for measuring LDL uptake by rat aortic endothelial cells in vivo, using a fluorescent marker (Dil)-labelled LDL and quantifying the fluorescence in cells selectively removed from the aorta. This technique was used to study the endothelial uptake of LDL modified by activated human monocytes (LDL-A) in comparison with native LDL (LDL-N) protected from oxidation by vitamin E during the preparation. Incubation of LDL with activated monocytes increased endothelial uptake in vivo by 9.3-fold and also by 4.4-fold in cultured confluent porcine endothelium. In contrast, only a 1.5-fold increase in uptake of LDL-A was observed in sparse cultures. Cytotoxicity of monocyte-altered or native LDL did not differ as measured by the [3H]deoxyglucose-release test on cultured endothelium. Our results suggest that modification of LDL in the circulation by monocytes may make an important contribution to atherogenesis.

Animals↗

PubMed1986

Cultured capillary endothelial cells from bovine adipose tissue: a model for insulin binding and action in microvascular endothelium.

Capillary endothelial cells were cultured from bovine adipose tissue. The endothelial nature of the cultures was documented by characteristic morphology, uniform presence of factor VIII antigen, and uptake of the endothelial cell marker Dil-Ac-LDL. The capillary cell cultures had specific, high affinity binding sites for insulin, demonstrating time and temperature dependence of binding, pH optimum, analog specificity, and inhibition of insulin binding by anti-insulin receptor antibodies. In both subconfluent and confluent cultures, insulin stimulated thymidine incorporation into DNA; significant stimulatory effects of insulin were observed at insulin concentrations of 1 ng/ml with maximal 8- to 10-fold increases at hormone concentrations of 1,000 to 10,000 ng/ml. Because of the ease of routine preparation, cell purity, presence of high affinity insulin binding sites, and insulin-sensitive metabolic responses, we suggest that the bovine capillary endothelial cultures could serve as a model cell system for the detailed study of insulin interactions with capillary endothelial cells.

Adipose Tissue↗

PubMed1979

Decay rate of inspiratory muscle pressure during expiration in man.

Decay rate of inspiratory muscle pressure (PmusI) was studied in 4 subjects during post-inspiratory period of zero flow (TEz) occurring under discontinuous inspiratory elastic load (DIL). End-inspiratory pressure (PmuseI) was increased by dead spaces or exercises. Decay rate was related to PmuseI by a power function with exponent greater than 1. It was not directly affected by concomitant changes of PCO2. It did not increase when an expiratory resistive load was added, i.e. when braking action of inspiratory muscles was no longer required. Time course of PmusI during TEz was more straight than exponential. Relative decay rate increased with PmuseI and with decrease of inspiratory or expiratory time. Experiments with resistive loads suggest that relative rate is mainly related to timing factors. During voluntary inspiratory efforts with closed airways, relative decay rate was not related to PmuseI, while decay rate increased linearly with PmuseI.

Adult↗

PubMed1991

Macrophage-like cells originate from neuroepithelium in culture: characterization and properties of the macrophage-like cells.

Cultures of astroglia from C3H/HeJ mice, which are resistant to bacterial cell wall polysaccharide (LPS), initiated from embryos of Theiler stage 14 (9 days of gestation) up to Theiler stage 25 (17 days of gestation) as well as newborn animals, when subjected to nutritional deprivation, i.e. non-feeding of cultures, form large numbers of macrophage-like cells. These cells express Mac-1, Mac-3, F4/80 and Fc antigens. The cells are negative for GFAP, positive for vimentin, express Ia antigen and take up DiL-Ac-LDL. They are positive to non-specific esterase, secrete lysozyme and are phagocytic. Their morphology and ultrastructure closely resemble those of macrophages. Cultures initiated from neuroepithelium of Theiler stage 13 (8.5 days of gestation), before vascularization, when subjected to nutritional deprivation, also produce macrophage-like cells. Using spleen colony assay and methyl cellulose cultures, we were unable to detect the presence of hemopoietic (macrophage) precursor cells in astroglia cultures. This supports the hypothesis that the macrophage-like cells are of neuroectodermal origin and probably correspond to resident microglia of the CNS. Using nutritionally deprived astroglia cultures, a procedure was developed for isolation of macrophage-like cells and production of highly enriched macrophage-like (microglia) cultures.

Animals↗

PubMed1990

Retinal axon pathfinding in the optic chiasm: divergence of crossed and uncrossed fibers.

In the developing mammalian visual system, retinal fibers grow through the optic chiasm, where one population crosses to the opposite side of the brain and the other does not. Evidence from labeling growing retinal axons with the carbocyanine dye Dil in mouse embryos indicates that the two subpopulations diverge at a zone along the midline of the optic chiasm. At the border of this zone, crossed fibers grow directly across, whereas uncrossed fibers turn back, developing highly complex terminations with bifurcating and wide-ranging growth cones. When one eye is removed at early stages, uncrossed fibers from the remaining eye stall at the chiasm midline. These results suggest that crossed and uncrossed retinal fibers respond differently to cues along the midline of the chiasm and that the uncrossed fibers from one eye grow along crossed fibers from the other eye, both guidance mechanisms contributing to the establishment of the bilateral pattern of visual projections in mammalian brain.

Animals↗

PubMed1992

Cholinergic differentiation factor (CDF/LIF) promotes survival of isolated rat embryonic motoneurons in vitro.

We present evidence that the cholinergic differentiation factor (CDF), originally purified from cardiac and skeletal muscle cell-conditioned medium and found to be identical to leukemia inhibitory factor (LIF), promotes survival of embryonic day 14 rat motoneurons in vitro. These neurons were retrogradely labeled with the fluorescent tracer Dil and enriched on a density gradient or purified to homogeneity by fluorescence-activated cell sorting. Subnanomolar concentrations of CDF/LIF supported the survival of 85% of the motoneurons that would have died between days 1 and 4 of culture. The enhanced survival was accompanied by a 4-fold increase in choline acetyltransferase (ChAT) activity per culture. CDF/LIF also increased ChAT activity in dorsal spinal cord cultures, but had no detectable effect on ChAT levels in septal or striatal neuronal cultures. For comparison, other neurotrophic molecules were tested on motoneuron cultures. Ciliary neurotrophic factor had effects on motoneuron survival similar to those of CDF/LIF, whereas basic fibroblast growth factor was somewhat less effective. Nerve growth factor had no effect on the survival of rat motoneurons.

Animals↗

PubMed1992

Selective dependence of mammalian dorsal root ganglion neurons on nerve growth factor during embryonic development.

We have investigated the NGF dependence of dorsal root ganglion (DRG) neurons in mammals using a paradigm of multiple in utero injections of a high titer anti-NGF antiserum. We have determined the specificity of our antiserum in relation to other members of the NGF neurotrophin family and found no cross-reactivity with brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3). To identify various classes of DRG neurons, we have stained their characteristic central projections with Dil. We show here that the NGF dependence of DRG neurons is strikingly selective. Although a majority of DRG neurons are lost after NGF deprivation during embryonic life, these are almost exclusively small diameter neurons that project to laminae I and II of the dorsal horn and presumably subserve nociception and thermoreception. Larger neurons that project to more ventral spinal laminae and subserve other sensory modalities do not require NGF for survival. These NGF-independent DRG neurons likely require one of the more recently identified neurotrophins, BDNF or NT-3.

Afferent Pathways↗

PubMed1991

Human monoclonal antibodies demonstrate polyreactivity for histones and the cytoskeleton.

Systemic lupus erythematosus (SLE) and other autoimmune diseases are characterized by immune responses to intracellular, highly conserved antigens such as DNA and histone. In this study, peripheral blood lymphocytes (PBL) from a patient with histone autoantibodies were used to prepare IgM human-human hybridoma cell lines. Indirect immunofluorescence (IIF) was used to identify monoclonal antibodies that bound to cytoskeletal and other cytoplasmic constituents. These supernatants did not bind double-stranded or single-stranded DNA. However, immunoblotting revealed that 7/20 hybridomas selected for their binding to cytoskeletal components produced antibodies that also bound mammalian and avian histones. When peptide fragments of histone were used in immunoblotting experiments, it was found that the monoclonal antibodies bound to the carboxyl terminus of H1, a region previously shown to bind autoantibodies from sera of patients with SLE and drug-induced lupus (DIL). When the amino acid sequences of histones and cytoskeletal components were compared using the Swiss-Prot protein data bank, it was confirmed that there are eight regions of similarity. While the significance of polyreactive human monoclonal antibodies to cytoskeletal components and histones is not understood at present, it is possible that the human histone antibodies represent polyreactive antibodies that arise through the mechanism of molecular mimicry.

Amino Acid Sequence↗

PubMed1989

Attenuation of neurotoxicity following anoxia or glutamate receptor activation in EGF- and hippocampal extract-treated neuronal cultures.

Neurotoxicity following anoxia or glutamate receptor activation was studied in primary neuronal cultures grown in serum-free, chemically defined CDM R12 medium. Exposure to 1 mM KCN, 0.5 mM kainic acid and 0.5 mM N-methyl-D-aspartate led to progressive neuronal degeneration. This damage was quantified by measuring lactate dehydrogenase released in the culture medium. The toxic effects were observed early during the development of the neuronal culture (from 4 days in vitro on) and seemed to be neuron-specific since astrocyte cultures were not affected. Chronic treatment of the neuronal cultures with epidermal growth factor at 10 ng/ml and hippocampal extract at dil. 1/833 (w/v) induced morphological alterations, increased beta-adrenergic receptor coupled adenylate cyclase activity, increased level of total lactate dehydrogenase activity in the case of epidermal growth factor-treated cultures, and attenuation of lactate dehydrogenase release following exposure to KCN or glutamate receptor agonists. The alterations observed are probably due to the proliferation and differentiation of glial cells in these treated cultures. This suggests that glial cells protect neurons in vitro from degeneration induced by anoxia or glutamate receptor activation.

Adenylyl Cyclases↗

PubMed1989

A sicca syndrome in HIV infection: association with HLA-DR5 and CD8 lymphocytosis.

A sicca syndrome with parotid enlargement, pulmonary insufficiency, and lymphadenopathy was seen in 12 patients infected with human immunodeficiency virus (HIV), only 1 of whom has had an opportunistic infection during 304 patient months of study. There was a striking increase in numbers of circulating CD8 lymphocytes and the prevalence of HLA-DR5 was greatly increased. In patients with this diffuse infiltrative lymphocytosis syndrome (DILS) the CD8 lymphocytosis, which probably depends on histocompatibility antigen status, may influence disease progression in HIV infection.

AIDS-Related Complex↗

PubMedDate not supplied

Growth of thalamic afferents into mouse barrel cortex.

We studied thalamocortical afferent (TCA) growth into somatosensory cortex as the whisker barrels emerge in postnatal mice. Ingrowing fibers from the ventrobasal (VB) thalamus were selectively labeled by two means. Under direct vision, individual axons and populations of axons were labeled in vitro with HRP, or in fixed tissue with Dil (1,1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), in pieces of brain containing both the source nucleus in the thalamus and its cortical target. Many simple thalamocortical afferents are already within the upper cortical plate at birth [postnatal day one (PND1)]. Initially, TCAs from each point in the thalamus distribute in the cortex as two-dimensional "Gaussians," which overlap laterally to constitute a uniform projection pattern. The projection is topographic, because adjacent focal injections within VB label adjacent cortical loci. Subsequent development of barreloids (thalamic representations of the whiskers) partitions the TCA projection into a set of whisker-related Gaussians, centered on cortical targets whose collective topography reflects that of the source pattern. After barreloids form on about PND3, but before barrels appear in cytoarchitecture on about PND5, the overlapping TCAs segregate into dense terminal clusters in layer IV, around which barrels later mature. Time series of single fibers traced with camera lucida explain this transformation that is so noticeable at the population level. As early as PND1, individual TCAs emit multiple ascending collaterals on their horizontal run through white matter and oblique ascent into upper cortex. Subsequently, by PND4, and proceeding at least through PND7, there is accelerated terminal arborization of selected appropriate collateral branches and pruning back of other inappropriate ones. The selection mechanism appears to result from within-group reinforcement events that are stronger for branches toward the center of each whisker-related Gaussian distribution.

Animals↗

PubMedDate not supplied

A comparison of pattern formation by thalamocortical and serotonergic afferents in the rat barrel field cortex.

In the present study we compare the formation of vibrissa-related patterns by thalamocortical afferents from the ventrobasal (VB) nucleus to that by raphe-cortical, serotonergic afferents from the raphe nuclei. In opposite hemispheres of the same brain, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) labeling of VB afferents and serotonin (5-HT) immunohistochemistry reveal that the pattern of vibrissa-specific patches is first exhibited by thalamocortical axons in barrel field cortex. Shortly thereafter, 5-HT axons form patches in the same locations as the dense concentrations of VB afferents. To assess a possible role of 5-HT afferents in the specification of barrel field cortex, neonatal rat pups were administered p-chloroamphetamine (PCA), a selective 5-HT neurotoxin. The formation of vibrissa-related patterns by thalamocortical and serotonergic afferents was compared in normal and PCA-treated rat pups at various developmental stages. PCA treatment led to a significant decrease in the number of serotonergic axons in barrel field cortex. Despite this decrease, VB afferents segregated in patches over individual barrels. However, a delay in the emergence of the thalamocortical pattern was noted in toxin-treated animals. We conclude that PCA treatment does not prevent formation of a vibrissa-specific pattern by thalamocortical afferents, and discuss the possibility that the 5-HT axons may play a trophic role in the maturation of VB afferents.

Animals↗

PubMed1989

Isolation, culture, and characterization of endothelial cells derived from the post-capillary venules of sheep mesenteric lymph nodes, Peyer's patches, and associated small bowel.

Lymphocyte recirculation is mediated principally by specialized endothelial cells which line the post-capillary venules of lymph nodes and other secondary lymphoid tissues. The ontogeny and physiology of this process have been characterized in sheep in considerable detail. To further enhance the analytical potential of this experimental system we have isolated endothelial cells from the post-capillary venules of ovine mesenteric lymph nodes by perfusion with small (37-74 microns diameter), sulfonated microcarrier beads. Cells isolated in this manner have been maintained in vitro for greater than 12 months through greater than 30 passages. The endothelial nature of these cells has been conclusively established on the basis of morphologic, metabolic, and immunologic criteria. Virtually all (greater than 99%) cells in primary and passaged cultures metabolized Dil-AC-LDL, a known marker for endothelial cells. Furthermore, nearly all (greater than 95%) cells expressed cell-surface von Willebrand factor and antithrombin III, which are known endothelial antigens. All cells expressed major histocompatibility class I antigens but no cells expressed class II antigens. In vitro lymphocyte-binding studies revealed that these cells bound lymphocytes in a dose-dependent fashion. The microcarrier perfusion technique was also used to isolate endothelial cells from the post-capillary venules of ileal Peyer's patches and associated small bowel in sheep. The majority (70%) of cells isolated in this manner resembled the cells isolated from mesenteric lymph nodes both morphologically and metabolically.

Animals↗