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Biomedical subjects

J Cambar

Publications and source records attributed to J Cambar.

At least 91 records · Page 5Linked to original sources
PubMed1978

[Evidence of urinary glomerular basement membrane (GBM) antigens excretion in 3 rodents (rat, mouse, and guinea-pig) (author's transl)].

Immunodiffusion technique, with rabbits antibodies against rat glomerular basement membrane (GBM), permits to evidence the presence of GBM antigens into normal urines of 3 rodents (rat, mouse, and guinea-pig). These results confirm the earlier works in human and rabbit urines and show the antigenic communauty existing between the 3 rodents GBM, since we can evidence antigens of 3 different mammals with the same antibody. The origin and the nature of this patterns and the signification of this presence into mammalian urines are discussed.

Animals↗
PubMed1978

The myorelaxant effect of theophylline on smooth muscle cells of the afferent arterioles and glomerular tuft.

Theophylline, infused i.v. into rats increased the diameter of the glomerular afferent arterioles by 35.78%; when added to a suspension of isolated glomeruli, it increased the diameter of the capillary tuft within the glomerulus by 25-30%. These variations in diameter can be explained by the myorelaxant effect of theophylline on the smooth contractile fibers present in the arteriolar cells and in certain glomerular cells, such as the mesangial cells. These observations explain, in part, the marked changes in glomerular hemodynamics caused by the injection of theophylline.

Animals↗
PubMed1978

[Circadian rhythmus of the excretion of electrolytes and urinary proteins in rats].

Circadian rhythms in urinary water, sodium, potassium and proteins excretion are studied in 45 rats living alone in metabolism cages. Urines are collected during 4 consecutive 6 hours long periods during 2 consecutive days. Large circadian variations of these parameters (especially water and proteins excretion and urinary protein concentration) are described. The influence of feeding rhythms on the circadian urinary excretion rhythms is discussed. It is proposed that nightly renal hemodynamic changes (during meal digestion or with high renin plasma levels) can induce modifications in glomerular filtration rate and electrolytes and macromolecules transglomerular flow.

Animals↗
PubMed1978

[Repartition of the kidney cortex glomerulus in rats].

This paper presents the repartition of 989 glomeruli in 8 parallel concentric renal cortex zones, by projecting on a calibrated screen rat kidney slices photographies. The glomerular density increases regularly from the outside to the middle cortical zones and then decreases to the deepest juxtamedullary zones.

Animals↗
PubMed1978

[Comparative effect of theophylline on urinary protein excretion in rats during diurnal and nocturanal periods].

In 3 lots of 15 rats, urinary proteins excretion (U.P.E.) during 6 hours periods is compared : 1) daily and nightly in physiological conditions, where U.P.E. increases nightly (+ 97,47%) : 2) daily, before and after theophylline injection, where U.P.E. increases after theophylline injection (+ 78,62%) ; 3) nightly, before and after theophylline injection, where U.P.E. increase is only tiny (+ 3,53%) after theophylline injection. So, in nightly physiological and in daily experimental conditions the important U.P.E. increases can be in part explained by those of renal functions. This result can explain after nightly theophylline injection (where renal functions are already very higher than in daily period) the so small nightly proteinuria increase with the xanthic diuretic ; it cannot be compared to the daily value, because the renal functions cannot increase beyond some limits. Lastly, the present paper exhibits how a pharmacomolecule (as theophylline here) can act differently daily and nightly and open a new investigation field in chronopharmacology of diuretics.

Animals↗
PubMed1978

[Nycthemeral variations of blood and urine urea, creatinine and total proteins in rats].

The present study evidences blood and urine urea, creatinine and total proteins circadian variations in 50 male rats. Venous blood is sampled at behind socket sinus once a week at different hours (8, 11, 14, 17, 20, 23, 2 and 5) and urines are collected during 4 consecutive six hours periods in animals living in metabolism cages (8-14, 14-20, 20-2, 2-8). Blood three nitrogen substances circadian variations bring out the decrease at 17 h and increase at 23 or 2 h. Urinary excretion variations curves shows, in all cases, an increase more than 40% during the nightly periods. The influence of feeding rhythms on the blood and urine three derivates circadian rhythms is discussed. Moreover, night diuresis increase and urea and creatinine urinary remarkable constancy suggest water, solutes and macrosolutes transglomerular pathway nightly increase existence. Urea (+ 40%) and creatinine (+ 30%) clearance nightly significative increase confirms glomerular filtration circadian variations and its nightly increase.

Animals↗
PubMed1978

[Correlation of structural and ultrastructural modifications of the renal cortex with water, sodium and protein excretion in rats rendered hypertensive by perinephritic constriction by collodion].

Water, sodium and proteins renal excretion in with collodion Page's method hypertensive rats is compared with that of same Wistar strained control rats. Blood pressure of treated animals (n = 16) is 193.1 Hg mm (138 in control rats). Urinary flow increases from 19.5 to 33.7 ml/24 h (+ 72.8%), sodium excretion from 29.6 to 37.5 mg/24 h (+ 26.7%) and total proteins excretion from 23.5 to 63 mg/24 h (+ 169%. This data are correlated with the renal cortex morphological changes with photon and electron microscope. Severe damages are seen in Bowman's capsule and in glomerular copruscules, especially at the epithelial layer level. Important proteic pools occur within tubular lumen. Proximal tubular epithelium seems normal. On the other hand, distal tubular epithelium seriously scales. So, important water, sodium and proteins excretion increase in our experimental hypertension model can be explained. It is also discussed about functional and structural modifications analogy in our model's rats and in spontaneously hypertensive rats (SHB).

Blood Pressure↗
PubMed1977

[Transglomerular passage of protein macromolecules in the rat : attempt at quantitative evaluation using ferritin].

The present microscopic study evaluates precisely the density of ferritin-particules in several substructures of the glomerular barrier, particularly the endothelial barrier, and the glomerular basement membrane, 15 and 60 minutes after the injection of the tracer. This quantitative method opens the way to numerous studies on the pathway of this protein-tracer through the glomerular substructures in the normal and pathologic rat.

Animals↗
PubMed1977

[Excretion in rat urine of substances derived from the basal glomerular membrane].

We have prepared in rabbits antibodies against rat GBM, with GBM prepared from isolated glomeruli issued from rat renal cortex. It is shown with immunodiffusion technique the excretion of basement membrane-like fragments into the normal rat urine. This result confirms the earlier works studying the human and rabbit urines. The origin and the nature of this patterns, the signification of this presence into the mammalian urines are discussed.

Animals↗
PubMed1977

[Effect of theophylline on diuresis and the physiological proteinuria of white rats].

The present study considers the quantitative variations of the physiologic proteinuria with theophyllin in the rat. The urins are collected, during 8 hours, every Rat being its own reference. The single theophyllin injection (20 mg/kg) induces an increased diuresis (+ 42,1 %) and proteinuria (+ 73,7 %). The repetitive theophyllin injections (during 5 days) confirms this constation. The hypothesis of a modification of the permeability of the glomerular barrier to proteic macromolecules is proposed to agree this result.

Animals↗
PubMed1977

[Effect of theophylline on the glomerular pathway of ferritin macromolecules in rats].

The present microscopic study evaluates the quantitative variations of ferritin particules density within the glomerular ultrastructures after theophyllin perfusion in the Rat. The ferritin particules density increases 3,65 times in the glomerular basement membrane and decreases 3,28 times in the glomerular capillary lumen. So, theophyllin increases considerably the glomerular pathway of the protein macromolecules. This results confirm the increased volumic flow (Jv) and macro-solutes flow (Js') noted with clearance methods and urinary excretion studies.

Animals↗
PubMedDate not supplied

In vitro effects of cadmium on two different animal cell models.

The aim of this study was to assess comparatively the effects of cadmium on two different in vitro cell models, a cell line derived from proximal tubule renal cells (LLC-PK1) and haemocytes or blood cells of mussels (Mytilus galloprovincialis). Cells were seeded in 96-well microplates and exposed in vitro to different concentrations of cadmium (CdCl(2)) ranging from 10 to 2000 microM for haemocytes and from 1 to 100 microM for LLC-PK1 cells, added to the culture medium. After 24 h of exposure, different assays were performed on haemocytes: neutral red uptake, phagocytosis of neutral red-stained zymosan, XTT assay, activity of lysosomal acid phosphatase and demonstration of the actin cytoskeleton using TRITC-labeled phalloidin. Cell viability expressed as LC50 was 750 microM when using the neutral red assay and 400 microM with the XTT assay. The phagocytic ability and the activity of acid phosphatase increased significantly in cells treated with Cd in a non dose-dependent manner. Doses of Cd above 100 microM caused disruption of the actin cytoskeleton. In LLC-PK1 cells, cell viability expressed as LC50 was found to be around 40 microM when using the neutral red assay and 50-60 microM with MTT and LDH assays, respectively. These results show that mussel haemocytes are in general more resistant to Cd exposure than LLC-PK1 cells. Furthermore, Cd appears to stimulate phagocytic and lysosomal activities in haemocytes in vitro.

Acid Phosphatase↗
PubMedDate not supplied

Cadmium nephrotoxicity assessed in isolated rat glomeruli and cultured mesangial cells: evidence for contraction of glomerular cells.

Cadmium (Cd), an important pollutant, causes severe damage at the renal tubular level. Numerous previous studies have focused upon Cd tubular nephrotoxicity. The present study of Cd-induced glomerular damage examined the vasoactive effect of Cd in freshly isolated glomeruli and mesangial cells. Glomeruli were isolated by passing rat renal cortex pulp through calibrated sieves followed by culture for outgrowth of cells. Quantitative evaluation of glomerular and cellular contractions was performed by morphometric measurement of the area with an automatized image analyzer following different incubation times with Hanks' balanced salt solution or Cd2+. Each glomerulus or mesangial cell served as its own control. Cd lethality was measured with microassay methods (neutral red, MTT uptake, and lactate dehydrogenase release), allowing the determination of an IC50. This ranged from 35 to 60 microM. CdCl2 induced a time-dependent contractile effect on isolated glomeruli; planar surface area decreases were 6.9% (1 microM), 7.5% (0.1 microM), and 7% (0.01 microM). The decrease started as soon as Cd was in contact with glomeruli and ended 40 min later: T5 (2%), T10 (3.5%), T20 (4. 2%), T30 (6.3%), T40 (7%). Cell size reduction was 19% (1 microM), 14% (0.1 microM), and 18% (0.01 microM) and was also time-dependent. To confirm that contractile events occurred during the cell shape changes, examination of the mesangial alpha-actin network was performed concurrently. These results indicate that Cd contracts glomerular structures. This may, in part, explain the reduction in glomerular filtration seen in Cd nephrotoxicity.

Actins↗