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  • Life and Medical Sciences  (7)
  • 31.30.Gs  (2)
  • 35.10.Bg  (2)
  • Na+/H+ antiport  (2)
  • Nitidulidae  (2)
  • 1990-1994  (13)
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  • 1
    ISSN: 1432-1440
    Keywords: Na+/H+ antiport ; Hypertension ; Diabetic nephropathy ; Hereditary factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The incidence of diabetic nephropathy in patients with insulin-dependent diabetes mellitus (IDDM) may depend on factors other than the quality of diabetes control. Hypertension is an additional factor associated with a high degree of renal involvement in IDDM. One abnormality consistantly observed in various tissues of patients with essential hypertension is enhanced activity of the Na+/H+ antiport. In the present study we have therefore studied platelet antiport activity in 41 healthy subjects (control), in 22 patients with untreated essential hypertension (EH), and in 35 normotensive IDDM patients (type 1). Of these patients 17 exhibited signs of diabetic nephropathy (group 1) while 18 had no evidence for renal involvement of IDDM in spite of a duration of IDDM of at least 10 years (group 2). The two IDDM patient groups were undistinguishable with respect to age, body mass index, and arterial blood pressure (group 1, 117.9±2.4/78.4±1.5 mmHg; group 2, 113.9±3.6/76.1±1.8 mmHg). Antiporter activity was determined from the rate of cell volume changes induced by propionic acid. Platelet Na+/H+ exchange activity averaged 23.43±0.43 10−3·s−1 in control subjects and was markedly elevated in EH (28.38±0.62 10−3·s−1 P〈0.01). Antiport activity in group 2 patients without nephropathy averaged 24.54±0.57 10−3·s−1 and was undistinguishable from the control group. However, platelet Na+/H+ antiport activity was significantly stimulated in group 1 patients with nephropathy as compared to group 2(26.95±0.73 10−3. s−1 ; P〈0.025). Our results show that renal involvement in IDDM is associated with enhanced activity of the platelet Na+/H+ antiport.
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  • 2
    ISSN: 1432-1440
    Keywords: Cell volume regulation ; Hypertonicity ; Lymphocytes ; Na+/H+ antiport ; Saline infusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The Na+/H+ antiport is a membrane transport protein that extrudes intracellular protons in exchange for extracellular sodium. Some details of its physiological and pathophysiological role remain poorly defined. Experimental evidence suggests that the antiporter is involved in the regulation of cell volume. In the present study, we therefore investigated the activity of the lymphocyte Na+/H+ antiport in nine healthy volunteers following acute hypertonic (2.5%) saline infusion (4 mmol NaCl/kg over 120 min). Antiport activity was measured after acidifying the cells with Na+ propionate (5–40 mM) using the fluorescent dye bis-carboxyethyl carboxyfluorescein. Hypertonic saline induced significant increases in plasma osmolality (308.4±2.3 vs. 293.5±2.7 mOsm/kg; P〈0.01), serum Na+ (150.8±3.7 vs. 138.9±0.5 mmol/kg; P〈0.01), and Cl− concentrations (118.0±3.9 vs. 101.1±1.0 mmol/kg; P〈0.01). Extracellular hypertonicity was followed by a stimulated activity of the lymphocyte Na+/H+ antiport with an increase in the apparent V max values from 2.44±0.16 to 3.27±0.34 10−3 s−1 (P〈0.01) and a slight rise in pK from 6.81±0.03 to 6.87±0.03 (P〈0.05) after hypertonic saline. In addition to antiport activation, cytosolic alkalinization was observed with cytosolic pH values averaging 6.90±0.02 before and 6.99±0.02 (P〈0.01) after hypertonic saline. Our results show for the first time that acute extracellular hypertonicity in man due to hypertonic NaCl loading is associated with a stimulated lymphocyte Na+/H+ antiport activity and cytosolic alkalinization.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 20 (1994), S. 1483-1493 
    ISSN: 1573-1561
    Keywords: Carpophilus obsoletus ; sap beetle ; Coleoptera ; Nitidulidae ; aggregation pheromone ; hydrocarbon ; tetraene ; date
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Males ofCarpophilus obsoletus Erichson produce an aggregation pheromone to which both sexes respond. The pheromone was identified by GC-MS as (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-undecatetraene (1), which is also a minor constituent of the pheromone blends ofC. hemipterus (L.),C. freemani Dobson, andC. lugubris Murray. The pheromone was synergized in wind-tunnel bioassays by propyl acetate, a “host-type” coattractant. In a dose-response study, 50 pg of1, plus propyl acetate, was significantly more attractive than just propyl acetate. Pheromone emission from groups of 65 males, feeding on artificial diet, averaged 2.2 ng/male/day. Emissions from individual males were larger, averaging 72 ng/day and ranging as high as 388 ng/day. Synthetic1 was tested in a date garden in southern California (500 µg/rubber septum), using fermenting whole-wheat bread dough as the coattractant. The pheromone plus dough attracted significantly more beetles than dough alone (means were 4.2 and 0.0 beetles per week per trap). Captured beetles were 54% females. Field trap catches were highest during the months of July and August.
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  • 4
    ISSN: 1573-1561
    Keywords: Carpophilus mutilatus ; sap beetle ; Coleoptera ; Nitidulidae ; aggregation pheromone ; hydrocarbon ; triene ; date ; host volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Males ofCarpophilus mutilatus Erichson produce an aggregation pheromone to which both sexes respond. The pheromone includes two hydrocarbon components, (3E,5E,7E)-5-ethyl-7-methyl-3,5,7-undecatriene (1) and (3E,5E,7E)-6-ethyl-4-methyl-3,5,7-decatriene (2). These were emitted in a 10∶1 ratio and in a total amount of ca. 5 ng per feeding male per day. All tested doses of1 and2, from 0.03 to 30 ng, were more attractive than controls in wind-tunnel tests, but there was no evidence of synergism between these trienes. Dramatic synergism between the pheromone and a food-type coattractant occurred in the field, however. In a date garden in southern California, traps with a combination of synthetic1 and fermenting whole-wheat bread dough attracted 22 times more beetles than dough by itself and 295 times more than1 by itself. Volatile collections from males also contained three oxygenated compounds that were absent from females. One of these was tetradecanal (ca. 5 ng per male per day), but the structures of the other two are presently undetermined (0.8 and 1.1 ng per male per day). No function for these was demonstrated. One compound originating in the artificial diet, 2-phenylethanol, was particularly attractive in the wind-tunnel bioassay, as was the chromatographic solvent, methanol.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 24 (1992), S. 161-164 
    ISSN: 1434-6079
    Keywords: 32.70.Jz ; 31.30.Gs ; 35.10.Bg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The use of an effusive beam of titanium atoms crossed with a CW single-mode tunable dye laser has allowed the high-resolution, Doppler-free study of the isotope shifts between50Ti,48Ti and46Ti, for seven 3d 2 4s 2 a3 F J → 3d 2 4s 4p z 5 D J , visible transitions of Ti I. The measurements show without ambiguity the existence of a non-negligible field shift. Using the values of the nuclear radii of titanium (coming from muonic X-ray measurements), it is possible to determine the respective values of the field and mass shifts.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 31 (1994), S. 145-148 
    ISSN: 1434-6079
    Keywords: 32.70.Jz ; 31.30.Gs ; 35.10.Bg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High accuracy measurements of hyperfine structure due to47Ti and49Ti in the 3d 2 4s 2 a 3 F 2−3d 2 4s4p z 5 D 1 absorption line at σ=18482.772 cm−1 have been performed by use of a Doppler-free experiment, where a beam of titanium atoms is crossed by a CW single mode tunable dye laser. They have allowed for the determination of isotope shifts between46Ti,47Ti,48Ti,49Ti and50Ti. By use of accurate values of mean square nuclear charge radii for the even isotopes, it has been possible to separate mass shifts from field shifts and to determine accurate values for the mean square nuclear charge radii of47Ti and49Ti. The field shift presents a marked odd-even staggering.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 151 (1992), S. 215-227 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human bone cells grown in culture, representative of a preosteoblastic stage of maturation, produce an extracellular matrix composed of collagen several noncollagenous glycoproteins, hyaluronan, and four distinct proteoglycans (PGs). The influence of donor age on the levels of expression of these molecules in vitro has not been well characterized. In this study, human bone cells derived from sources ranging from fetal to 60-year-old donors were grown in culture, radiolabeled for 24 h, and the amount of incorporation of [35S]sulfate into PGs, [3H]glucosamine into hyaluronan, [3H]leucine/proline into osteonectin, and [3H]proline into collagen was determined. Cell proliferation was most rapid in fetal-derived bone cells and decreased with increasing age. Total protein and PG synthesis also decreased with increasing age, falling to 1/3 and 1/4, respectively, of fetal levels after age 30. A large chondroitin sulfate PG (Mr ∼ 600,000 Da) was the major fetal PG and its levels were highly correlated with cellular proliferation. [3H]Collagen and [35S]decorin levels increased with the increasing age of the donor, reached a maximum in puberty-derived cells, and decreased to 1/3 maximal levels after age 20. The heparan sulfate PG (Mr ∼ 400,000 Da) exhibited steadystate levels regardless of donor age. [3H]Osteonectin and [35S]biglycan levels were high in fetal-derived cells and in cells derived from pubescent donors. The percentage of collagen and four proteoglycans associated with the cell layer pool changed with donor age. All fetal-derived PG core proteins possessed more N- and O-linked oligosaccharides than newborn or adult derived PGs. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 144 (1990), S. 115-121 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Alkaline phosphatase, long implicated in biomineralization, is a feature of the osteoblast phenotype. Yet in cultured bone cells, only a fraction stain positive histochemically. To determine whether osteoblast enzyme expression reflects cellular heterogeneity with respect to cell cycle distribution or length of time in culture, the activities of alkaline phosphatase, tartrate-resistant and -sensitive acid phosphatases, and non-specific esterases were assayed kinetically and histo-chemically. In asynchronous subconfluent cultures, 〈 15% of the cells stained positive and assayed activity was 0.04 IU/106 cells/cm2. After 1 week, the percent of alkaline phosphatase positive-staining cells increased 5-fold, while activity increased 10-fold. Non-specific esterases and tartrate-sensitive acid phosphatase were constitutive throughout time in culture, whereas tartrate-resistant acid phos-phatase activity appeared after 2 weeks. Cell cycle analysis of human bone cells revealed a growth fraction of 80%, an S phase of 8.5 h, G2 + 1/2 M of 4 h, and a G1 of 25-30 h. In synchronous cultures induced by a thymidine-aphidicolin protocol, alkaline phosphatase activity dropped precipitously at M phase and returned during G1. A majority of the alkaline phosphatase activity lost from the cell surface at mitosis was recovered in the medium. Tartrate-sensitive acid phos-phatase and non-specific esterase levels were relatively stable throughout the cell cycle, while tartrate-resistant acid phosphatase activity was not assavable at the density used in synchronous cultures. From these data, variations in alkaline phosphatase activity appear to reflect the distribution of cells throughout the cell cycle.
    Additional Material: 6 Ill.
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  • 9
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We studied the expression of osteoblastic markers in cultured cells isolated from the bone of 15 patients with different clinical forms of osteogenesis imperfecta (OI) and of seven fetal and postnatal controls. Cultured bone cells of ten OI patients produced abnormal collagen type I. Similar to controls, OI bone cells produced predominantly collagen type I with traces of collagen types III and V. The 1,25(OH)2 vitamin D3-stimulated synthesis of osteocalcin, a specific osteoblastic marker protein, was similar in OI bone cells and age-matched controls. Bone cells from fetal controls and from patients with the perinatal lethal OI type II produced less osteocalcin than bone cells from postnatal controls and surviving OI patients. OI bone cells responded to parath.yroid hormone (PTH) by increased production of cAMP similar to controls. Bone cells from fetal controls and from OI type II donors showed a decreased response to PTH. Activity of the bone-liver-kidney isoenzyme alkaline phosphatase (AP) was detected in all control and OI bone cells. The expression of all osteoblastic markers was similar in bone cells producing abnormal collagen type I. These observations show that OI bone cells in vitro express a pattern of osteoblastic markers similar to age-matched control bone cells indicating that osteoblastic differentiation is not altered by the underlying defects of collagen type I metabolism in OI bone cells. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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  • 10
    ISSN: 0749-503X
    Keywords: Multi-gene family ; ATPases ; proteasome ; S. cerevisiae ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: There is accumulating evidence for a large, highly conserved gene family of putative ATPases. We have identified 12 different members of this novel gene family (the YTA family) in yeast and determined the nucleotide sequences of nine of these genes. All of the putative gene products are characterized by the presence of a highly conserved domain of 300 amino acids containing specialized forms of the A and B boxes of ATPases. YTA1, YTA2, YTA3 and YTA5 exhibit significant similarity to proteins involved in human immunodeficiency virus Tat-mediated gene expression but more significantly to subunits of the human 26S proteasome. YTA1 and YTA2 are essential genes in yeast. Remarkably, the cDNA of human TBP-1 can compensate for the loss of YTA1. Preliminary experiments indicate that YTA1 is a component of the 26S protease complex from yeast. Our findings lead us to propose that YTA1, YTA2, YTA3 and YTA5 function as regulatory subunits of the yeast 26S proteasome. YTA10, YTA11 and YTA12 share significant homology with the Escherichia coli FtsH protein, and together with YTA4 and YTA6 may constitute a separate subclass within this family of putative ATPases.
    Additional Material: 5 Ill.
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