Circannual variation in the fatty acid composition of high-density lipoprotein phospholipids during acclimatization in trout.

A circannual variation in the fatty acid composition of plasma and high-density lipoprotein (HDL) phospholipids occurs in rainbow trout (Oncorhynchus mykiss) in response to seasonal alterations in environmental water temperature. The compensatory mechanisms employed in cold adaptation include a decrease in the level of saturated fatty acids and of monoenes of the oleic acid (n-9) family and an increase in the level of unsaturated fatty acids of the linolenic acid (n-3) family, especially in docosahexaenoic acid (22:6(n-3)). The present study demonstrates that in trout, a poikilothermic vertebrate, the weight percentage of 22:6(n-3) in HDL phospholipids is inversely correlated (r = -0.88, P < 0.0001) with water temperature.

Effects of 17ß-estradiol and starvation on trout plasma lipoproteins.

Administering 17ß-estradiol (E2) to juvenile trout results in plasma hyperlipidemia and hyperlipoproteinemia associated with significant increases in the concentrations of triglycerides (TG), free cholesterol, phospholipids, free fatty acids and proteins, both postprandial and during starvation. TG undergo the greatest increase (9 times control level 96 h after feeding). The concentration differences between E2-treated and control trout increase during starvation, primarily by progressive decreases in the concentrations of various lipids in controls. E2-induced hypertriglyceridemia is mainly caused by an increase in the concentration of very low density lipoproteins (VLDL) during both the postprandial period (6 times control level at 24 h) and during starvation (15 times control level at 96 h); hyperlipoproteinemia lasts up to at least 7 d after the last feeding. E2 treatment does not change the concentration of high density lipoproteins, but does increase plasma concentrations of a very high density lipoprotein, vitellogenin (VTG). In E2-treated VLDL, cholesteryl esters are depleted while proteins are enriched. During the postprandial phase, the apolipoprotein (apo) profile of VLDL (d< 1.015 g/mL) is comparable in E2-treated and control trout. Starvation of E2-treated trout is accompanied by an enrichment in apo B240, A-I and A-II. The secretion levels of TG and VLDL-TG, as determinedin vivo, by injecting Triton WR-1339 to starving animals, are significantly higher in E2-treated trout than in controls. In trout, as in chicks, E2 administration significantly increases the concentration and hepatic secretion of plasma VLDL independent of the nutritional status and the appearance of VTG in the plasma. This suggests the existence of similar mechanisms for the regulation of lipoprotein metabolism by estrogens in oviparous vertebrates.

Thermal adaptation affects the fatty acid composition of plasma phospholipids in trout.

The adaptive changes in the fatty acid (FA) composition of plasma phospholipids (PL) in response to alterations in environmental water temperature were investigated in juvenile rainbow trout (Oncorhynchus mykiss). The changes observed during thermal adaptation from 22°C in summer to 8°C in winter were reproduced by laboratory cold acclimation (CA) at 6°C of 22°C-summer-acclimated animals. In cold-acclimated and winter-acclimated trout, the increase in the unsaturation of PL fatty acids was mainly due to an enrichment of approximately 7% in the total weight percentage of 22∶6n-3, while a concomitant significant decrease in the levels of 18∶0 and of the monoenoic n-9 FA was observed. A time course study revealed that the changes in PL fatty acids became significant after 10 d of CA and were complete after one month. These changes in the composition of the fatty acyl chains of plasma total PL indicate that the FA composition of plasma lipoprotein PL does not remain constant during thermal adaptation. This would suggest that plasma lipoproteins provide a rapid systemic supply of lipids containing more or less unsaturated FA during thermal adaptation of poikilothermic animals.

Age-related, sex-related, and seasonal changes of plasma lipoprotein concentrations in trout.

Seasonal variability in physiological parameters can be attributed to seasonal variations in environmental factors and/or to the consequence of the presence of endogenous circannual rhythms. In the current study we have measured plasma levels of lipids and of the different lipoprotein classes in fasting trout (Oncorhynchus mykiss) between the ages of 5 and 44 months. Independent of age and sexual maturity, a circannual variation in the low density lipoprotein concentration between 250 and 1300 mg/dl was demonstrated in both sexes. These seasonal fluctuations might be controlled by an endogenous biological clock synchronized by the photoperiod. The lipoprotein profile of trout is dominated by high density lipoproteins as early as the first months of life. Their concentration increases progressively during sexual maturation from about 1200 mg/dl in juveniles to about 2500 mg/dl during spermiation or at the moment of ovulation. This increase is highly significantly correlated with the increased concentration of testosterone occurring in both sexes during sexual maturation. The concentration of very low density lipoproteins increases substantially, from about 150 mg/dl to a maximal concentration of 800 mg/dl in females and 1100 mg/dl in males, during the deposit phase of lipid reserves which precedes the rapid increase in the gonadosomatic ratio. In the course of rapid ovarian growth, vitellogenin appears in the plasma of females and reaches a concentration of 2200 mg/dl 1 month before ovulation. From these results it is concluded that season and reproductive cycle are the two main factors affecting basal plasma lipid and lipoprotein levels in trout. Environmental factors such as photoperiod or endocrine factors such as the concentration of steroid hormones can be correlated and/or involved in the regulation of these quantitative variations. These results also suggest the presence of an endogenous biological clock able to exert an independent effect on plasma lipid and lipoprotein levels.

[Combined intravenous arteriography and pyelography in hypertension. I. -- Technical and diagnostical aspects on the bases of 475 cases (author's transl)]. / Le temps artériel de l'urographie intraveineuse dans l'hypertension artérielle. I. -- Aspects technique et diagnostique de 475 observations.

UNLABELLED: Renal arteriogram can be obtained by a rapid injection (15-22 ml/s) of a venous bolus of 2-3 ml/kg B.W. of contrast media at 38 p. 100 and followed by an excretory pyelography with early films and wash out by furosemide to determine the functional significance of an eventual stenosis in a hypertensive patient. Analysis of 2 000 such radiological examinations, 475 of which done in hypertensive patients, showed that a stenosis could be adequatly detected in 70 p. cent of the cases when only one arteriographic film was taken and in 95 p. 100 of the cases when 6 films were taken with a film changer. With this latter technique the morphological information was comparable to that obtained with the Seldinger technique. This latter was however necessary to confirm the stenosis preoperatively when only one arteriographic film was taken. Tolerance of the examination was good in spite of transitory heat sensation and headache in 66 p. cent of the cases. The examination of 475 hypertensive patients led to discover 55 renal artery stenosis, 12 of which were functionnal, 4 aneurysms (1 of the renal artery, 2 of the aorta, and 1 of the hepatic artery) and one coarctation. IN CONCLUSION: combined intravenous arteriography and pyelography is a valuable technic, as regards, safety and efficiency in the diagnosis of renovascular hypertension. This warrants a comparison of this technique with the classical diagnostic approach of renovascular hypertension as regards its diagnostic efficiency and cost for the community.

[Arterial time of intravenous pyelography: initial results (author's transl)]. / Temps artériel de l'urographie intraveineuse. Premiers résultats

The authors consider that attention should be paid to the arterial time in intravenous pyelography in all patients who undergo the examination. Manual injection or an injector containing 80 to 100 ml of 38% iodine contrast medium set at a speed of 20 ml/sec, on the one hand, and films taken during the arterial phase on the other hand, are the two conditions necessary to obtain a satisfactory arteriogram. Slight abdominal compression and subtraction improve the definition of the films. 600 cases have been collected so far, in the exploration of 105 patients with hypertension, 17 cysts, 7 malignant tumours, extra-renal pathology and various nephropathies in which no indication for arteriography existed. Thus pyelographic arteriography made it possible to avoid renal arteriograms in almost all our patients. Only one selective and one complete arteriogram were necessary. Unusual arterial lesions in nonsurgical renal conditions may be seen (glomerulonephritis, nephroangiosclerosis...) and unexpected images in abdominal conditions with renal manifestations or in association with nephropathies (aneurysms of digestive arteries and the aorta, collagen diseases etc.).

Depressed urokinase activity in bronchoalveolar lavage fluid from patients with sarcoidosis, silicosis or idiopathic pulmonary Rbrosis: relationship to disease severity.

Intraalveolar fibrinolysis, is regulated by the concerted actions of plasmin, plasminogen activators (PAs), and their specific inhibitors (PAIs). This event is considered as a critical step in the pathogenesis of pulmonary fibrosis. The aim of this study was to evaluate whether local PA activity can be held as a marker of fibrosis in chronic interstitial lung disorders (ILD). Changes in both PA activity and PA-related proteins (urokinase-type PA (uPA), tissue-type PA (tPA), PAI-1 and PAI-2) were assessed in bronchoalveolar fluid (BALF) of 60 subjects: 18 healthy controls, 18 non-fibrotic sarcoidosis patients, 16 patients with idiopathic pulmonary fibrosis (IPF) and eight silicotic patients with established fibrosis. We observed a significant decrease of BALF PA activity in the three groups of patients as compared with controls. Reduction in BALF PA activity was compatible with lower uPA protein levels associated, especially in IPF patients, with an increased occurrence of PAI-1 and PAI-2 antigens. Soluble tPA antigen was never detected either in control subjects or in patients. Most importantly, the reduction in BALF PA activity and uPA protein levels was found to be most severe in patients with advanced fibrotic disease, namely IPF, while moderate and only weak alterations were found in silicosis and non-fibrotic sarcoidosis, respectively. In addition, significant positive correlations were found between BALF PA activity and functional impairment as assessed by TLC % and DLCO%. Finally, the reduction in uPA and PA activity levels observed in BALF from sarcoidosis patients was found to be proportional to the degree of BAL lymphocytosis. These findings indicate that an intense reduction in BALF PA activity is associated with severe stages of the parenchymal disease, possibly reflecting the degree of the fibrotic process.