Microsphere entrapped bee-venom phospholipase A2 retains specific IgE binding capacity: a possible use for oral specific immunotherapy.

The only specific treatments of allergy are long and exacting desensitization by subcutaneous injections of the allergens. While oral administration of allergens could greatly facilitate these treatments, effective delivery systems are needed to prevent allergen degradation in the gastrointestinal tract and to enable their uptake by Peyer's patches. The potential for bee-venom phospholipase A2 (PLA2) to be used in such oral immunotherapy was tested.

Fluoride ion toxicity in rabbit kidney thick ascending limb cells.

Background And Objective: Some halogenated agents, especially methoxyflurane, because of a higher level of fluoride production, induce a renal concentrating defect that could be related to an ascending limb impairment. We investigated the mechanisms of fluoride toxicity on an immortalized cell line.

Methods: Cells were cultured for 2, 6 or 24 h in the presence of fluoride.

Erythropoietin enhances recovery after cisplatin-induced acute renal failure in the rat.

Background: Erythropoietin (Epo) is a growth factor whose synthesis mainly takes place in the kidney. Epo has been shown to support the growth not only of erythroid progenitor cells but also of certain other cell types. We attempted to establish whether Epo enhances the recovery from acute renal failure induced by cisplatin.

Preclinical profile of the monodisperse iodinated macromolecular blood pool agent P743.

Rationale And Objectives: To summarize the chemical synthesis, physicochemical characterization, pharmacokinetic behavior, and biological evaluation of P743, a new macromolecular iodinated contrast medium.

Methods: The synthesis and molecular modeling of the iodinated macromolecule P743 are described. The pharmacokinetic profile was established in rabbits and rats.

Synthesis and polymerization of benzyl (3R,4R)-3-methylmalolactonate via enzymatic preparation of the chiral precursor.

beta-methylaspartate ammonia-lyase, EC 4.3.1.

N-acetyl-beta-D-glucosaminidase (NAG) isoenzymes in primary cultures of rabbit kidney proximal tubule cells: a cellular model for studies on nephrotoxicity?

N-Acetyl-beta-D-glucosaminidase (NAG) isoenzyme profile in primary cultures of rabbit kidney proximal tubule cells was studied. Confluent cells had high levels of NAG activity, but ion exchange chromatography showed that the NAG isoenzyme profile in cultured cells was different from that of rabbit renal cortex homogenates and freshly isolated cells. Confluent cultured cells contained an atypical acidic isoform, absent in homogenates and freshly isolated cells in which the predominant isoform is NAG-A (a heterodimer alpha beta).

Cultured proximal cells derived from transgenic mouse provide a model to study drug toxicity.

The effects of gentamicin on N-acetyl-beta-D-glucosaminidase (NAG) and acid phosphatase (AcP), two lysosomal enzymes present in proximal renal tubule cells, were studied in the PKSV-PCT cell line derived from proximal convoluted tubules from the kidney of a transgenic mouse carrying SV40 large T antigen under the control of the L-type pyruvate kinase gene. Gentamicin (400 micrograms/ml for 72 hr) did not alter cell viability, but significantly reduced cell growth and favored the formation of myeloid bodies. Gentamicin (50 to 800 micrograms/ml for 72 hr) decreased in a dose-dependent manner the cellular NAG in PKSV-PCT cells and stimulated its secretion by 20 to 60%.

Characteristics and regulation of 11 beta-hydroxysteroid dehydrogenase of proximal and distal nephron.

Enzymatic properties of the enzyme 11 beta-hydroxysteroid dehydrogenase (11-HSD), which confers mineralocorticoid selectivity, have been explored in the aldosterone-sensitive collecting duct (CCD) and the aldosterone-insensitive Pars Recta (PR) of the rat kidney. After incubation of freshly isolated tubular segments with [3H]corticosterone (3H-B) or [3H]dehydrocorticosterone (3H-A), the rate of transformation of 3H-B into 3H-A (dehydrogenase activity), or the reverse reaction (reductase activity) were measured by HPLC, Vmax for dehydrogenase activity was found to be 8- to 10-fold higher in CCD than PR. The enzyme functions over a very wide range (0.

Comparative effects of low- and high-osmolar contrast media on the renal function during early degenerative gentamicin-induced nephropathy in rats.

The nephrotoxic potentials of a high-osmolar contrast medium, diatrizoate, and of a low-osmolar contrast medium, ioxaglate, were compared during early degenerative gentamicin-induced nephropathy in the rat. Male rats (13-22/group) were uninephrectomized. Six days later, the aorta was clamped above the renal artery, and either diatrizoate or ioxaglate was administered (1 ml/min for 3 min) via an aortic puncture into the remaining kidney.

Iobitridol, a new nonionic low-osmolality contrast agent, and iohexol. Impact on renal histology in the rat.

Rationale And Objectives: To compare the histologic effects on rat tubular cells of two nonionic contrast media with equivalent osmolalities and viscosities.

Methods: Histologic, functional (creatinine clearance), and biochemical (proteinuria and enzymuria) profiles of iohexol and iobitridol (both at 350 mg I/mL) were compared in the uninephrectomized rat. A control group (n = 14) received compared isotonic saline solution.

Renal tolerance of gadolinium-DOTA and gadolinium-DTPA in rats.

Rationale And Objectives: Although gadolinium chelates are mainly eliminated by the kidney, there is limited information about their effects. The renal tolerance of these compounds on renal function in an in vivo rat model are evaluated.

Methods: A combination of renal ischemia and intrarenal iodinated contrast agent infusion (diatrizoate) led to a reproducible and reversible model of acute renal failure (n = 5).

Modulation of the renal effects of contrast media by endothelium-derived nitric oxide in the rat.

Rationale And Objectives: A possible involvement of endothelium derived relaxing nitric oxide (NO) in the pathogenesis of iodinated contrast media (CM)-induced nephrotoxicity was investigated in the rat.

Methods: Male rats (6 to 12 per group) were uninephrectomized. Six days later, the aorta was clamped above the renal artery and a low-osmolar contrast medium (CM), ioxaglate, was injected (1 mL/min; 3 minutes) via an aortic puncture in the single remaining kidney.

Comparative nephrotoxicity of carboplatin and cisplatin in euvolemic and dehydrated rats.

The aim of this study was to compare the renal tolerance of cisplatin and carboplatin in euvolemic and dehydrated rats. A total of 79 euvolemic or dehydrated male rats were randomly assigned to receive cisplatin (5 mg/kg body weight, i.p.

Chronic cisplatin nephropathy in rats.

The long-term renal effects of cisplatin have been very poorly studied. Therefore we investigated the chronic renal effects of various doses of cisplatin in three groups of male Sprague-Dawley rats. Group I received two injections of 5 mg/kg body weight (bw) at 4-week intervals, group II four injections of 2.

Adrenalectomy reduces alpha 1 and not beta 1 Na(+)-K(+)-ATPase mRNA expression in rat distal nephron.

The abundance of mRNA of alpha 1-, alpha 2-, alpha 3-, beta 1-, and beta 2-isoforms of Na(+)-K(+)-ATPase was examined in several renal structures of normal and adrenalectomized (ADX) rats. In situ hybridization with 35S-labeled cRNA probes was performed on kidney sections from adult rats. The number of silver grains per unit surface area was quantified over cells of the glomerulus, proximal convoluted tubules (PCT), early distal tubules (EDT), and cortical collecting ducts (CCD).

Hexosaminidase and alkaline phosphatase activities in articular chondrocytes and relationship to cell culture conditions.

Hexosaminidase and alkaline phosphatase activities in rabbit articular chondrocytes have been studied under different cell culture conditions. Chondrocytes were cultured in monolayer primary culture, monolayer subcultured to the fifth passage (in vitro aging) and cultured within a collagen gel; enzymatically released cartilage cells were used as control. Under these conditions, the two enzymes behave quite differently in relationship to alteration of the chondrocyte phenotype in culture.

Renal tolerance of AMI 25.

The objective of this study was to evaluate the renal tolerance of a new magnetic resonance contrast agent, AMI 25. This agent has an affinity for the reticuloendothelial system and is used for the detection of focal liver lesions. A combination of renal ischemia and intra-arterial iodinated contrast agent infusion (diatrizoate) leads to a reproducible and reversible model of acute renal failure in the rat.

[Hexosaminidase and alkaline phosphatase in cartilage and chondrocyte cultures obtained from normal and arthritic rabbit joints].

Hexosaminidase and alkaline phosphatase activities were studied in a rabbit model of osteoarthritis. Enzyme activities were determined in cartilage slices and cultures of chondrocytes from normal and arthritic joints. Alkaline phosphatase activity was increased in cartilage slices from rabbits with osteoarthritis, as compared with normal cartilage, whereas no difference was seen for hexosaminidase activity.

N-acetyl-beta-D-glucosaminidase (NAG) isoenzymes release from human monocyte-derived macrophages in response to zymosan and human recombinant interferon-gamma.

Secretion of N-acetyl-beta-D-glucosaminidase (NAG) isoenzymes by human blood monocyte-derived macrophages in response to zymosan and human recombinant interferon-gamma was studied. Macrophages were found to release NAG in response to zymosan, but interferon-gamma has no effect on secretion. Isoenzyme separation by isoelectric focusing demonstrates that non stimulated and zymosan or interferon-gamma treated macrophages release predominantly NAG B and, to a lesser extent, NAG A isoenzymes.

Renal effects of S10036 in man.

The renal hemodynamic and tubular effects of S10036 (fotemustine) were evaluated in seven patients with advanced malignancy. Initial evaluation carried out prior to treatment and repeated 1 day after the first fotemustine infusion and 7 days after the second included clinical, haematological parameters, liver-function tests, and determination of the glomerular filtration rate, renal blood flow and enzymuria. The glomerular filtration rate was 108 +/- 3.

Renal effects of radiocontrast agents in rats: a new model of acute renal failure.

The objectives of this study were first to develop a reproducible and reversible model of acute renal failure following contrast medium infusion in the rat; second to use that method to compare the nephrotoxicity of low- and high-osmolar contrast agents. Contrast media or saline were perfused in the aorta while a clamp was applied on the aorta just above the renal artery. Three minutes of renal ischemia with or without infusion of isotonic saline induced no change in serum creatinine and a slight and transient decrease in creatinine clearance at 24 h.

Effects of retinoic acid on the growth of cultured rabbit articular chondrocytes: Relation with alkaline phosphatase activity and beta receptor.

The effects of retinoic acid (RA) on rabbit articular cartilage cells were studied for concentrations ranging from 5.10(-5) M to 10(-7) M; the treatment with RA over three days resulted in dose dependent inhibition of chondrocyte proliferation between 5.10(-5) and 10(-5) M with persistence of the inhibitory effect until 10(-6) M.

Sodium butyrate-induced structural and functional modifications in proteins of cultured rabbit articular chondrocytes.

The effects of sodium butyrate (NaB), a potent growth inhibitory agent, on actin distribution, alkaline phosphatase (AP) activity and protein content were studied in rabbit articular chondrocytes in monolayer culture. When growth of randomly proliferating cells was arrested with NaB, actin stress fibers appeared; at the same time, vimentin-containing intermediate filaments and tubulin-containing microtubules were dispersed. Concomitantly, membrane AP activity and protein content were increased.