Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0428
    Keywords: Keywords Insulin-dependent diabetes mellitus ; diabetic nephropathy ; G protein activation ; cellular signalling ; lymphoblasts ; platelet-activating factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Genetic susceptibility contributes significantly to the risk of developing nephropathy in insulin-dependent diabetes mellitus (IDDM). The cellular substrate for this has remained enigmatic. We investigated whether afflicted IDDM patients display an enhanced activation of pertussis toxin (PTX)-sensitive G proteins, a phenomenon which has been demonstrated in patients with essential hypertension. We established immortalised B lymphoblast cell lines from 10 IDDM patients without nephropathy (DC) and 15 IDDM patients with nephropathy (DN). Nephropathy was defined as a persistent albumin excretion rate of more than 20 μg/min (DC 3.9 ± 5.8, DN 562.3 ± 539.0 μg/min, respectively). Subjects were matched with regard to age (DC 28.9 ± 6.5, DN 35.9 ± 9.9 years), diabetes duration (DC 19.3 ± 6.9, DN 22.7 ± 5.8 years) and HbA1 c values (DC 8.5 ± 1.4, DN 8.8 ± 1.6 %). Reactivity of PTX-sensitive G proteins was quantified by measuring platelet-activating factor (PAF)-induced Ca2 + mobilisation (fura 2 method) and by mastoparan-stimulated [35S]GTPγS binding. Expression of Gαi proteins was quantified by Western blot analysis. PAF-evoked Ca2 + increases above baseline averaged 77.0 ± 52.5 nmol/l in DC and 150.7 ± 61.5 nmol/l in DN (p = 0.005). PAF-evoked Ca2 + increases correlated with stimulated [35S]GTPγS binding (r 2 = 0.42, p = 0.012). From Western blot analysis an overexpression of Gαi proteins could be excluded in DN. A consequence of the altered metabolic milieu in diabetes is the increased release of vasoactive and proliferative agonists which promote glomerular hyperfiltration, hypertrophy, enhanced matrix deposition, and, finally, glomerulosclerosis. Many of these auto- and paracrine agonists bind to G protein-coupled receptors. Therefore, their cellular effects are reinforced by the enhanced G protein reactivity and increase the propensity to nephropathy in IDDM. [Diabetologia (1998) 41: 94–100]
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Biomembranes 1148 (1993), S. 185-190 
    ISSN: 0005-2736
    Keywords: (Platelet) ; Epinephrine ; Intracellular pH ; Sodium ion-proton exchange ; pH, intracellular
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 121 (1984), S. 266-270 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 141 (1986), S. 13-19 
    ISSN: 0006-291X
    Keywords: [abr] Bt"2-cAMP; dibutyrylic cAMP ; [abr] DG; diacylglycerol ; [abr] DMSO; dimethylsulfoxide ; [abr] IP"3; inositol 1,4,5-trisphosphate ; [abr] OAG; 1-oleoyl-2acetylglycerol ; [abr] PGE"1; prostaglandin E"1 ; [abr] PGI"2; prostaglandin I"2 ; [abr] PIP"2; phosphatidylinositol 4,5-bisphosphate ; [abr] Pk-C; protein kinase C ; [abr] TFP; trifluoperazine ; [abr] TPA; 12-0-tetra-decanoylphorbol-13-acetate
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 141 (1986), S. 13-19 
    ISSN: 0006-291X
    Keywords: [abr] Bt"2-cAMP; dibutyrylic cAMP ; [abr] DG; diacylglycerol ; [abr] DMSO; dimethylsulfoxide ; [abr] IP"3; inositol 1,4,5-trisphosphate ; [abr] OAG; 1-oleoyl-2acetylglycerol ; [abr] PGE"1; prostaglandin E"1 ; [abr] PGI"2; prostaglandin I"2 ; [abr] PIP"2; phosphatidylinositol 4,5-bisphosphate ; [abr] Pk-C; protein kinase C ; [abr] TFP; trifluoperazine ; [abr] TPA; 12-0-tetra-decanoylphorbol-13-acetate
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 176 (1991), S. 639-644 
    ISSN: 0006-291X
    Keywords: [abr] BCECF; 2',7'-bis(carboxyethyl)-5,6-carboxy-fluorescein ; [abr] MIA; 5-(N-methyl-N-isobutyl)amiloride ; [abr] pH"1; cytosolic pH ; [abr] pH"o; extracellular pH
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 161 (1989), S. 1007-1012 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 125 (1984), S. 1123-1128 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...