The effects of N-methyl-D,L-aspartate and gonadotropin-releasing hormone on in vitro growth hormone release in steroid-primed immature rainbow trout, Oncorhynchus mykiss

L-Nicotine stimulates a biphasic release of [3H]dopamine from mouse striatal synaptosomes which does not persist after agonist is removed. Approximately 80% of the initial release is transient and disappears with a half-time of less than 1 min; the other 20% persists for several minutes (t(1/2), 5-10 min). Both the transient and persistent phases were investigated by 10-min exposures to agonists with an in vitro perfusion technique. A series of nicotinic agonists and antagonists were used to determine the pharmacological relationship of the two phases. Parameters measured included EC50 and Vmax values and desensitization rates for both phases for agonists, Ki values for antagonists and Ki values for low concentrations of agonists. The results are consistent with both phases being mediated by a single type of receptor. In addition, the effects of chronic nicotine treatment on transient and persistent [3H]DA release were measured. For both phases, release was decreased approximately 15% by chronic infusion of 4.0 mg/kg/hr L-nicotine. Correlation of the results with inactivation of a portion of the receptors rather than a reversible desensitization is discussed.     

Isolation and characterization of insulin-like growth factor-I from rainbow trout, Oncorhynchus mykiss

Fatty acids were estimated in plasma and red blood cell membrane in rats, rabbits, dogs and humans. The fatty acid pattern of plasma and red blood cell membrane was similar in all species and humans with little exceptions. C18:2 was higher in plasma than red blood cell membrane whereas C20:4 was higher in red blood cell membrane than plasma except rabbit. C18:2 was high in rabbit red blood cell membrane when compared to others. Dog was exceptionally very low in C18:2 and high in C20:4 in red blood cell membrane whereas rabbit was low in C20:4 and high in C18:2. 22-Carbon fatty acids showed some variation. Among 22-carbon fatty acids C22:6 was found highest in human red blood cell membrane, with quite high amounts in rat and rabbit but not in dog. Rats were closest to human in their fatty acid patterns.     

Toxicological and kinetic study of musk xylene in rainbow trout, Oncorhynchus mykiss

In a prospective study of 6301 surgical patients in a university hospital, we examined the strength of association between ASA physical status classification and perioperative risk factors, and postoperative outcome, using both univariate analysis and calculation of the odds ratio of the risk of developing a postoperative complication by means of a logistic regression model. Univariate analysis showed a significant correlation (P < 0.05) between ASA class and perioperative variables (intraoperative blood loss, duration of postoperative ventilation and duration of intensive care stay), postoperative complications and mortality rate. Univariate analysis of individual preoperative risk factors demonstrated their importance in the development of postoperative complications in the related organ systems. Estimating the increased risk odds ratio for single variables, we found that the risk of complication was influenced mainly by ASA class IV (risk odds ratio = 4.2) and ASA class III (risk odds ratio = 2.2). We conclude that ASA physical status classification was a predictor of postoperative outcome.     

Characteristics of two salmonid repetitive DNA families in rainbow trout, Oncorhynchus mykiss

DNA sequence and genomic location of two repetitive DNA families in rainbow trout (Oncorhynchus mykiss) were investigated to develop molecular markers for chromosome identification. DNA fragments with sequences similar to the tandem and interspersed elements described in other salmonids were isolated. One clone showed differential hybridization to 12 pairs of chromosomes and should be a useful marker for physical mapping.     

Effects of steroids on GTH I and GTH II secretion and pituitary concentration in the immature rainbow trout Oncorhynchus mykiss

Using specific radio-immunoassays for rainbow trout GTH I and GTH II, the effects of testosterone and estradiol 17 beta have been studied or reinvestigated on the regulation of the secretion and the synthesis of the these two pituitary gonadotropins in the immature rainbow trout. After steroid implantation, the GTH II pituitary concentration is stimulated by testosterone and estradiol 17 beta for the entire period during which the plasma levels of these hormones are maintained to values comparable to those measured in the adult vitellogenic female rainbow trout. On the other hand, only testosterone induced a transient increase in the GTH I pituitary content 15 days after implantation, and estradiol provoked a decrease at day 30. The secretion of both GTH I and GTH II is stimulated by testosterone but not by estradiol 17 beta. Altogether, these results show that in the immature rainbow trout, testosterone preferentially modifies GTH I secretion, but not that of GTH II. They confirm that the stimulation of GTH II accumulation after testosterone or estradiol treatment would correspond to a stimulation of hormone synthesis. They evidence a differential action of both steroids on the synthesis of the two gonadotropins, especially a possible inhibition of GTH I synthesis by estradiol. They let suppose that the regulation of GTH I synthesis would involve factors other than steroids.     

Studies on the eosinophilic granule cells in the gills of the rainbow trout, Oncorhynchus mykiss

Hypoxic-ischemic changes in brain are detected earlier with diffusion-weighted (DW) than with T2-weighted magnetic resonance (MR) imaging techniques in adults, whereas the response in immature brain is not known. We investigated MR imaging changes prior to, during, and/or after 2 h of hypoxia-ischemia (right carotid artery occlusion + 2 h of hypoxia) in 7-day-old rats anesthetized with isoflurane. In general, within the first 45 min of hypoxia-ischemia there were no changes in the DW or T2-weighted images. By the second hour of hypoxia-ischemia there were marked areas of increased intensity in both the T2 and the DW images, with cortex and striatum being affected prior to thalamus and hippocampus. The area of DW exceeded that of T2 hyperintensities. In the first hour after hypoxia-ischemia there was a transient recovery of hyperintensities on both T2 and DW images. Between 24 and 72 h the hyperintense area on DW images decreased, whereas that on T2-weighted images increased. The distribution of pathological damage assessed histologically correlated with the areas of hyperintensity on the MR images. In contrast to adult brain, early hypoxic-ischemic injury in immature brain is detected as an increase in intensity in both diffusion- and T2-weighted images, indicating a unique alteration in brain water dynamics in this neonatal model of hypoxia-ischemia. These imaging changes and alterations in brain water can rapidly but transiently reverse upon the start of normoxia and reperfusion, suggestive of secondary energy failure or delayed neuronal death.     

Lectin histochemistry of rainbow trout (Oncorhynchus mykiss) gill and skin

In order to characterize the glycoconjugate residues in skin and gills of the adult rainbow trout, the binding pattern of five biotinylated lectins with different carbohydrate specificities was examined. In the skin, mucous cells revealed binding sites for PNA and SBA; filament-containing cells were additionally labelled with Con A. However, the basal cell layer showed no reaction. In the gill, subpopulations of mucous cells reacted with Con A, PNA, SBA and UEA-I. This broader spectrum of glycoconjugates in gill mucous cells compared with the epidermal mucous cells could point to the additional function of gill mucus in ion and osmoregulation. Lectin binding sites were less common in the respiratory epithelial cells of the secondary lamellae than in those of the primary lamellae. Chloride cells revealed mannose, galactose and fucose residues. Immature chloride cells, as indicated by a comparison with Na+/K+ ATPase immunolabelling, reacted with Con A; subpopulations of them reacted with PNA, SBA and UEA-I. The results form the basis for further investigations in which these cell populations can be analysed under different environmental conditions.     

Cryptosporidium parvum: an attempt at experimental infection in rainbow trout Oncorhynchus mykiss

Segmental mediolytic arteriopathy, a rare, noninflammatory arterial disease, is fundamentally a variant of fibromuscular dysplasia. The characteristic angiographic findings of segmental mediolytic arteriopathy include the "string of beads" and microaneurysms which are indistinguishable from those of vasculitis, and the correct diagnosis can be made only after histopathologic evaluation of the arterial lesions. Thrombosis, arterial wall hemorrhage, and dissection are among the complications of segmental mediolytic arteriopathy. We describe herein a patient with segmental mediolytic arteriopathy who presented with hemoperitoneum. The patient underwent urgent surgical repair of a ruptured hepatic artery aneurysm. The postoperative visceral arteriography findings led to a clinical diagnosis of polyarteritis nodosa, and immunosuppressive therapy was initiated. This treatment was stopped as soon as the correct biopsy diagnosis of segmental mediolytic arteriopathy was obtained through outside consultation. The patient recovered without drug treatment and was spared the potentially life-threatening complications of immunosuppression.     

Oxygen consumption of juvenile rainbow trout (Oncorhynchus mykiss) exposed to sublethal concentrations of 1,2,4,5-tetrachlorobenzene and tetrachloroguaiacol

Dietary intake of highly polyunsaturated fats represents a major source of lipid hydroperoxides in the intestinal lumen. Under conditions of high peroxide intake, excessive concentrations of lipid hydroperoxides can persist in the gut lumen and contribute to impairment of mucosal GSH-dependent detoxication pathways, enterocyte dysfunction independent of cell injury, and development of gut pathologies, including cancer. This paper summarizes our current knowledge of the determinants of intestinal lipid hydroperoxide metabolism and of the physiological and biochemical processes in lipid peroxide-mediated changes in intestinal redox status, regulation of mucosal thiol and antioxidant balance and control of intestinal cell turnover. This discussion is pertinent to understanding dietary peroxides and thiol redox balance in intestinal physiology and pathophysiology and the potential benefit of oral GSH in preserving metabolic integrity of the intestinal epithelium.     

Characterization of biliary metabolites of 4-n-nonylphenol in rainbow trout (Oncorhynchus mykiss)

1. [R-2,6-3H]-4-n-nonylphenol was synthesized and a single dose (5 mg, 1850 KBq) orally administered to rainbow trout. After 48 h, the radioactivity present in the bile amounted 5.5%. More than ten biliary metabolites were separated by hplc and collected for subsequent mass spectrometry analysis. The metabolic profile was totally modified by beta-glucuronidase hydrolysis, showing that most of the metabolites were glucuronic acid conjugates. 2. Conjugated metabolites were identified by lc-ms analysis and their aglycones were analysed by gc-ms analysis as TMS and acetyl derivatives. 3. The major metabolite accounted for 52+/-11% of the biliary radioactivity and was identified as nonylphenol-glucuronide. 4. Nonylphenol was hydroxylated at both omega and omega-1 positions of the alkyl chain, giving 9-hydroxynonylphenol and 8-hydroxynonylphenol. 5. 9-Hydroxynonylphenol was oxidized to the corresponding acid, and subsequently beta-oxidized, yielding 7-(4-hydroxyphenyl)heptanoic acid, 5-(4-hydroxyphenyl)pentanoic acid, 3-(4-hydroxyphenyl)propionic acid and 3-(4-hydroxyphenyl)-2-propenoic acid.     

Accumulation of zinc in rainbow trout (Oncorhynchus mykiss) after waterborne and dietary exposure

An acromegalic patient with nontoxic autonomous goiter was sequentially treated with octreotide and bromocriptine. Before therapy, serum GH, PRL and insulin-like growth factor-I (IGF-I) levels were increased. Free T3 and free T4 were within the normal range with suppressed TSH levels, whereas 123Iodine-uptake of thyroid was 5.6% after 24 h. During treatment with octreotide and bromocriptine, serum GH, PRL, and IGF-I became normal and free T3 and free T4 were slightly but significantly decreased, but TSH levels remained very low. After thyroidectomy, thyroglobulin, free T3 and free T4 were further decreased, and the TSH levels were recovered to normal. These findings suggested that octreotide and bromocriptine inhibit the release of thyroid hormones from the autonomous thyroid gland directly or indirectly through the decline in IGF-I.     

Demonstration of tank effect on growth indices of juvenile rainbow trout (Oncorhynchus mykiss) during an ad libitum feeding trial

Growth indices were examined in 24 identically managed tanks, each containing 120 diploid juvenile rainbow trout (initial mean body weight, 9.3 g) during a 12-week study to examine tank effects associated with tank location in a multi user research facility. Growth indices included mean body weight, feed intake, feed conversion index, and specific growth rate. The null hypothesis that tank effect had no effect on growth over the 12-week period was rejected (P = 0.038), and mean weight in individual tanks differed by as much as 18.7%). During the study it was determined that the proximity of tanks to common-use walkways in the facility could affect growth indices. This was indicated by significant differences in the mean fish weights among blocks of tanks served by different header tanks after 4 (P = 0.001) and 8 (P = 0.024) week. The block containing tanks of fish with the highest them weight was nearest to the 2 common-use walkways in the facility. Fish in this block of tanks, compared with those in other blocks, had significantly greater feed intake but no significant differences in conversion efficiency. Compensatory growth, a well known growth attribute in fishes, diminished the difference in mean weight be tween these blocks of tanks by the end of the study. Comparison of paired ranks within header tank blocks indicated that fish in those located nearest to walkways had higher feeding rates over the 12-week period (P = 0.048), but less efficient feed conversion (P = 0.040) than did fish in matched tanks located farthest from walkways. However, there were no differences in mean weight of fish. Results of this trial document the risks involved in identifying fish in a tank as the experimental unit when treatments are administered to the tank of fish, the latter being the true experimental unit.     

Effect of a supplemental Aspergillus niger phytase on the utilization of plant phosphorus by rainbow trout (Oncorhynchus mykiss)

Effects of a supplemental Aspergillus niger-phytase on digestibility and utilization of dietary phosphorus (P) were studied in three experiments with rainbow trout. P concentration in the diets was 4.8 and 5.8 g/kg DM, respectively. The P contained in the diet originated solely from plants, mainly soy-products. Digestibility of P was studied using the stripping method and hydrochloride insoluble ash as marker. Utilization was studied in growth trials by use of the comparative body analysis. At a water temperature of 15 degrees C, both digestibility and utilization of P were increased from 25 to 57% and from 17 to 49%, respectively when 1000 U/kg phytase were supplemented. Feed consumption and gain of trout were significantly increased. At a water temperature of 10 degrees C, utilization of P was also increased from 6 to 25%. However, feed consumption and gain of trout were very low at this water temperature and not influenced by the supplemental phytase.     

Immunohistochemical localization of glucocorticoid receptors in the forebrain of the rainbow trout (Oncorhynchus mykiss)

The distribution of glucocorticoid receptor-expressing cells was studied in the forebrain of the rainbow trout by means of antibodies produced against a fusion protein made of the NH2-terminal fragment of the rainbow trout glucocorticoid receptor fused in frame with glutathione-S-transferase. The results indicate that glucocorticoid receptor-expressing cells are located in many brain regions from the telencephalon to the spinal cord, with the highest density in the neuroendocrine component of the brain, the preoptic region and the mediobasal hypothalamus, and in the periventricular zone of the optic tectum. In virtually all cases, the labeling was located in the nucleus of the cells, although on very rare occasions, a slight labeling of the cytoplasm was detected. Concerning the preoptic region, the most striking feature was the high density of glucocorticoid receptors in the magnocellular preoptic nucleus, known to contain corticotrophin-releasing factor (CRF)-, vasotocin-, and isotocin-expressing cells. Colocalization experiments showed that 100% of the CRF-immunoreactive neurons in the preoptic nucleus express glucocorticoid receptors. In the mediobasal hypothalamus, the highest expression was found in the nucleus lateralis tuberis and parts of the nucleus recessus lateralis. Concerning the pituitary, the glucocorticoid receptor was consistently found in the rostral pars distalis, with the exception of the prolactin cells, and in the proximal pars distalis, which in trout contains thyrotrophs, gonadotrophs, and somatotrophs. In the hindbrain, expression of glucocorticoid receptors were localized mainly in the periventricular regions.     

Somatostatin binding to hepatocytes isolated from rainbow trout, Oncorhynchus mykiss, is modulated by insulin and glucagon

A HPLC-method was developed to determine both fenoldopam, a weakly basic drug and succinic acid, a pH-adjuster for this drug in dissolution media. The usual assays for succinic acid were not applicable due to its low UV-absorption, the low pH-value of samples or the presence of buffer salts and fenoldopam. The described method is a simple non-ion-pair reversed phase HPLC-method using a fast scanning UV-detector and a PC software program for the quantification of both components. Succinic acid is detected at 205 nm and fenoldopam at 225 nm. The UV-spectrum is used to determine peak purity and to identify peaks (carried out at a 99.9% match). This is especially important as in some of the investigated samples an unknown peak elutes immediately after succinic acid, resulting in spurious high contents, if mistaken for succinic acid. The simple method accomplished the simultaneous quantification of both, succinic acid and fenoldopam, by an accurate, precise, specific and reproducible assay, with a linear range covering all concentrations relevant for dissolution testing. The method is stability indicating and can also be used for the quantification of fumaric acid, another pH-adjuster in dissolution media together with fenoldopam.     

CYP4T1--a cytochrome P450 expressed in rainbow trout (Oncorhynchus mykiss) liver

Total RNA isolated from a rainbow trout (Oncorhynchus mykiss) liver was subjected to RT/PCR using degenerate primers designed from homologous regions amongst cytochrome P450 CYP4 proteins. PCR amplification resulted in a single electrophoretic band which was excised, purified and sequenced directly, using cycle sequencing. The deduced protein sequence demonstrated the closest amino acid identity to rabbit CYP4B1 (54.6%) and rat CYP4B2 (55.4%). Phylogenic analysis of this sequence was found to be significantly different to any other CYP4 sequence and has been named CYP4T1. This represents the first CYP4 family member to be identified in an aquatic vertebrate.     

Effects of lindane exposure on rainbow trout (Oncorhynchus mykiss) immunity. III. Effect on nonspecific immunity and B lymphocyte functions

The effect of the organochlorine insecticide lindane (gamma-hexachlorocyclohexane) was examined on some major immune functions of rainbow trout (Oncorhynchus mykiss) on the chemiluminescent response of pronephric cells (PMA-induced) in phagocytosis, on the proliferation of lymphocytes with B and T mitogens, and on the number of B lymphocytes analyzed by cytofluorometry. Two different methods of exposure were tried via food (first protocol) and via a single intraperitoneal injection (second protocol). After the oral contamination at a daily body dose of 1 mg/kg for 30 days, a decreased chemiluminescent response was observed with persisted for two more weeks and disappeared over 1.5 months. No effect was observed on lymphocyte proliferation and on the number of circulating B lymphocytes. In the second protocol lindane was administered intraperitoneally at 10, 50, or 100 mg/kg body wt. After 45 days the lymphocyte proliferation of B cells was depressed but not the T cell one. The B cells number in head kidney as measured by cytofluorometry was not significantly modified. Some nonspecific immunity parameters in sera were significantly modified.