Relationship between omega-3 fatty acids and plasma neuroactive steroids in alcoholism, depression and controls.

Deficiency in the long-chain omega-3 fatty acid, docosahexaenoic acid (DHA) has been associated with increased corticotropin releasing hormone and may contribute to hypothalamic pituitary axis (HPA) hyperactivity. Elevated levels of the neuroactive steroids, allopregnanolone (3alpha,5alpha-THP) and 3alpha,5alpha-tetrahydrodeoxycorticosterone (THDOC) appear to counter-regulate HPA hyperactivity. Plasma essential fatty acids and neurosteroids were assessed among 18 male healthy controls and among 34 male psychiatric patients with DSM-III alcoholism, depression, or both. Among all subjects, lower plasma DHA was correlated with higher plasma THDOC (r = -0.3, P < 0.05) and dihydroprogesterone (DHP) (r = -0.52, P < 0.05). Among psychiatric patients lower DHA was correlated with higher DHP (r = -0.60, P < 0.01), and among healthy controls lower plasma DHA was correlated with higher THDOC (r = -0.83, P < 0.01) and higher isopregnanolone (3beta,5alpha-THP) (r = -0.55, P < 0.05). In this pilot observational study, lower long-chain omega-3 essential fatty acid status was associated with higher neuroactive steroid concentrations, possibly indicating increased feedback inhibition of the HPA axis.

SAP30L interacts with members of the Sin3A corepressor complex and targets Sin3A to the nucleolus.

Histone acetylation plays a key role in the regulation of gene expression. The chromatin structure and accessibility of genes to transcription factors is regulated by enzymes that acetylate and deacetylate histones. The Sin3A corepressor complex recruits histone deacetylases and in many cases represses transcription. Here, we report that SAP30L, a close homolog of Sin3-associated protein 30 (SAP30), interacts with several components of the Sin3A corepressor complex. We show that it binds to the PAH3/HID (Paired Amphipathic Helix 3/Histone deacetylase Interacting Domain) region of mouse Sin3A with residues 120-140 in the C-terminal part of the protein. We provide evidence that SAP30L induces transcriptional repression, possibly via recruitment of Sin3A and histone deacetylases. Finally, we characterize a functional nucleolar localization signal in SAP30L and show that SAP30L and SAP30 are able to target Sin3A to the nucleolus.

In vivo detection of vascular adhesion protein-1 in experimental inflammation.

Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial glycoprotein which mediates leukocyte-endothelial cell interactions. To study the pathogenetic significance of VAP-1 in inflammatory disorders, an in vivo immunodetection method was used to detect the regulation of luminally expressed VAP-1 in experimental skin and joint inflammation in the pig and dog. Moreover, VAP-1 was studied as a potential target to localize inflammation by radioimmunoscintigraphy. Up-regulation of VAP-1 in experimental dermatitis and arthritis could be visualized by specifically targeted immunoscintigraphy. Moreover, the translocation of VAP-1 to the functional position on the endothelial surface was only seen in inflamed tissues. These results suggest that VAP-1 is both an optimal candidate for anti-adhesive therapy and a potential target molecule for imaging inflammation.

Neuroprotection by the alpha2-adrenoceptor agonist, dexmedetomidine, in rat focal cerebral ischemia.

The present study was undertaken to explore the possible neuroprotective effect of the selective alpha2-adrenoceptor agonist, dexmedetomidine in a rat model of focal cerebral ischemia. The effect of dexmedetomidine (9 microg kg(-1)) on infarct volume was assessed and compared to that of glutamate receptor antagonists cis-4(phosphonomethyl)-2-piperidine carboxylic acid (CGS-19755) (20 mg kg(-1)) or 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) (50 mg kg(-1)). Dexmedetomidine decreased total ischemic volume by 40% in the cortex (P<0.05) compared to NaCl-treated control rats, whereas NBQX reduced the infarct by 73% in the cortex (P<0.001) and by 43% in the striatum (P<0.01). Dexmedetomidine infusion was associated with some minor degree of hyperglycemia and hypotension. Drug-induced kidney changes were only seen in NBQX-treated rats. These results suggest that dexmedetomidine reduced ischemic volume despite causing a minor increase in blood glucose concentrations and hypotension. Its neuroprotective efficacy was better than that produced by CGS-19775, and dexmedetomidine was safer with respect to kidney toxicity when compared to NBQX.

The effect of toremifene on bone and uterine histology and on bone resorption in ovariectomised rats.

The effect of the selective oestrogen receptor modulator, toremifene, to inhibit ovariectomy-induced bone loss was studied in rats. The oral doses were 0.3, 3.0 or 30 mg/kg/day for 2 months. 17beta-oestradiol (5 microg/kg/day, subcutaneously) was used as positive control. One group was also treated with a combination of 17beta-oestradiol (5 microg/kg) and toremifene (3.0 mg/kg). Biochemical markers were urinary hydroxyproline and calcium (adjusted with urinary creatinine levels) and the serum level of pyridinoline cross-linked carboxy terminal telopeptide, a bone specific collagen breakdown product. The femoral and sternal trabecular bone thickness served as histological parameters. Ovarectomy increased the levels of hydroxyproline and pyrodinoline and decreased the trabecular bone thickness compared to the sham-operated control group. This was inhibited by both test compounds but 17beta-oestradiol was more efficient. Toremifene did not reverse the ovariectomy-induced reduction of urinary calcium but inhibited the 17beta-oestradiol-related increase. When administered together with oestradiol, toremifene did not reverse the positive effect of 17beta-oestradiol on bone, however toremifene reversed the oestradiol-related uterothrophic effects. These findings indicate that the antagonistic features of toremifene dominate in the rat uterus the agonistic properties do in the bone.

The proliferation in uterine compartments of intact rats of two different strains exposed to high doses of tamoxifen or toremifene.

Uterine Cell proliferation was studied in intact Sprague-Dawley (SD) and Fischer 344 (F344) rats exposed to the antiestrogens tamoxifen (TAM; 5, 10, 20, or 40 mg/kg) and toremifene (TOR: 21.2 or 42.4 mg/kg). The antiestrogens were administered to animals via gavage daily for 2 or 12 wk. Uterine proliferation was assessed using markers for the proliferating cell nuclear antigen (PCNA) and by the bromodeoxyuridine (BrdU) method. Diethylstilbestrol (DES) was used as an estrogenic reference compound. The antiestrogens either reduced or prevented changes of myometrial and stromal proliferation indices (PI). TAM and TOR caused a time-dependent reduction of endometrial glands without an associated decrease in cell proliferation. In the luminal columnar epithelium, the antiestrogens depressed PCNA PI but enhanced BrdU PI, indicating a low continuous DNA synthesis in otherwise quiescent cells. The antiestrogens induced focal hyperplastic multilayered epithelia with PCNA-positive basal cells along segments of the luminal uterine epithelium. We suggest that this hyperplastic epithelium represents remnants from the glandular epithelium. DES was less efficient in inducing these changes but induced squamous metaplasias in the F344 rats. Uterine effects of the 2 antiestrogens were comparable with the exception of I TAM-exposed (40 mg/kg) SD rat that showed squamous metaplasia. F344 rats were more sensitive to the estrogenic action of DES than were the SD rats.

A two-year dietary carcinogenicity study of the antiestrogen toremifene in Sprague-Dawley rats.

The carcinogenic potential of the nonsteroidal triphenylethylene antiestrogen toremifene (Fareston) was evaluated in a standard 104-week rat dietary carcinogenicity study. The doses were 0, 0.12, 1.2, 5.0 and 12 mg/kg/day and the number of animals 50/sex/dose group. The body weight gain and food consumption were monitored once weekly (study weeks 1-16) or once every four weeks thereafter (study weeks 17-104). Blood samples were taken at weeks 34, 52 and 104 and the plasma concentrations of toremifene, as well as the two main metabolites (deaminohydroxy)toremifene and N-demethyltoremifene, were measured. All doses of toremifene reduced food intake and body weight gain. Toremifene caused a significant reduction in mortality, which was mainly due to reduced incidences of pituitary tumors. This was evident in all dose groups. Drug-related decrease of mammary tumors in females (at all doses) and testicular tumors in male rats (doses > or = 1.2 mg/kg/day) were also evident. The incidence of the preneoplastic foci of basophilic hepatocytes were significantly decreased in treated female groups. Toremifene induced no preneoplastic or neoplastic lesions. Based on histopathology, no obvious toxicity could be observed. Drug-related changes were observed in the genital organs, thyroid, spleen, mammary gland, adrenal, kidney, stomach and lung. These changes were due to hormonal disturbances or as a result of reduced food consumption or reduced incidences of pituitary, mammary or testicular tumors. This study indicates that toremifene is an efficient antiestrogen in long-term treatment, is well tolerated and has no tumorigenic potential in rats.

Tamoxifen induces hepatocellular carcinoma in rat liver: a 1-year study with two antiestrogens.

The effects of equimolar doses of the triphenylethylene antiestrogens tamoxifen and toremifene on female Sprague-Dawley rat liver were studied in a 52-week toxicity study which included a 13-week recovery period. Liver tumors were found in four out of five rats at the highest dose level of tamoxifen (45 mg/kg per day) after 52 weeks of dosing, and these appeared to be hepatocellular carcinomas in three rats. After the 13-week recovery period all surviving rats in the highest tamoxifen dose group had large liver tumors (diameter up to 2 cm) which appeared to be hepatocellular carcinomas in five out of six rats. No tumor was observed in the toremifene-treated rats (48 mg/kg per day) either after 52 weeks of dosing or after the recovery period. Electron microscopic morphometric analysis after 52 weeks of dosing revealed that at the tamoxifen high dose level, the volume densities of the peroxisomes, mitochondria, and residual bodies were elevated in the nonneoplastic hepatocytes of the rats. In the neoplastic hepatocytes of the tamoxifen-treated rats the volume density of nuclei was slightly elevated. The slight proliferation of peroxisomes and mitochondria might be related to tumor development in the tamoxifen treated rats.

The effect of antidiuretic hormone, indomethacin and naproxen on prostaglandin synthesis of experimentally infected and healthy kidneys.

The authors studied the effect of indomethacin and naproxen on the changes of renal prostaglandin E and F2 alpha concentration in experimental kidney infection, as well as the action of arginine-vasopressin in healthy rats. Naproxen proved to be an effective inhibitor of prostaglandin synthesis, as did indomethacin. In control animals an increased prostaglandin E and F2 alpha synthesis was observed caused by arginine vasopressin. It is supposed that ADH--depending on its concentration--has a metabolic modulator role in prostaglandin synthesis, which raises the possibility of a self-regulatory mechanism of water reabsorption.

On the enzymatic response to injury and its mediators.

The enzymatic response to injury appears as an increase in enzymatic activity in the periphery of burns and other injuries. The following processes constitute the enzymatic response: 1) release, 2) activation and 3) synthesis of enzymes. Processes 2) and 3) are dependent upon the fibroblast, which is an activated fibrocyte. Among the fibrocyte activators, and thus among the mediators of the enzymatic response, are histamine, serotonin, kinins, prostaglandins etc. The effects of non-steroidal anti-inflammatory drugs on the enzymatic response to burn injury were studied. Indomethacin, mefenamic acid or aspirin, suspended in carboxymethylcellulose, were given to rats by stomach tube. Controls received carboxymethylcellulose only. Circular burns were inflicted on anaesthetized animals which were killed 30 min, 2 h or 4 h after burning. The burns were studied histologically and enzyme histochemically by using the methods for prostaglandin synthetase, esterases, and adenosine triphosphatase. Aspirin had no effect on the enzymatic response. Mefenamic acid and indomethacin caused a less severe enzymatic response in the 4-h groups as compared to control rats.

Renal accumulation of amikacin, tobramycin and gentamycin in the rat.

Free and total concentrations of amikacin, tobramycin and gentamycin were measured separately in the rat kidney after equal weight by weight doses. The accumulation of aminoglycosides followed the order amikacin less than tobramycin less than gentamycin. The ratio between free and total aminoglycosides was similar (about 0.6) in all 3 aminoglycosides and independent on the length of administration.

The nephrotoxicity and renal accumulation of amikacin, tobramycin and gentamycin in rats, rabbits and guinea pigs.

The nephrotoxicity and renal concentrations of amikacin, tobramycin and gentamycin were studied in rat, rabbit and guinea pig. The nephrotoxicity was estimated by histological examination and by measuring the relative weight of the kidneys (mg/100 mg body weight). These two systems had a significant correlation (r = 0.87; p less than 0.001). The concentrations of aminoglycosides were determined by the cylinder-plate method measuring free aminoglycosides. The renal toxicity of the aminoglycosides in equal doses weight by weight followed the order amikacin less than tobramycin less than gentamycin in the rat. The same order was observed in the renal accumulation of the aminoglycosides in rat, rabbit and guinea pig. The critical kidney damaging concentration of free aminoglycoside in the whole rat kidney was estimated to be 160--190 microgram/g.

Pharmacokinetic studies of the antiarrhythmic drugs ajmaline and N-propylajmaline bitartrate in dogs.

A rapid, sensitive fluorometric method for the determination of ajmaline and N-propylajmaline (NPA) was used to follow serum concentrations after an i.v. administration of ajmaline, after an oral administration of ajmaline, and an oral dose of NPA bitartrate (NPAB) in beagle dogs. Ajmaline was eliminated from serum with an apparent half-life of approximately 1 h and NPA with one of approximately 4 h. 1 h after i.v. and oral administration of 50 mg of ajmaline the serum levels were of the same order of magnitude. The bioavailability of oral ajmaline, calculated from the area under the serum concentration/time curves, was about 90%. The peak serum concentrations of ajmaline and NPA after a single oral dose of 50 mg of ajmaline and NPAB were about 1.4 microgram/ml and 0.6 microgram/ml, respectively, the latter calculated as its bitartrate, with about the same peak time: 1 h.

Sex differences in renal damage induced in the mouse by Amanita virosa.

The sensitivity of male and female mice to Amanita virosa was compared. Dried, homogenized mushroom was given orally by stomach tubing at doses of 100, 200, 400 and 800 mg dried mushroom/kg body weight. Both in males and in females, the kidneys were the only organs showing macroscopical changes. The dose of 100 mg/kg caused renal damage in females, whereas in males the first signs of kidney damage were seen at the dose of 400 mg/kg. The renal lesions observed in the males were located in the cortex, while in the females they were limited to the outer stripe of the outer medullary zone. Testectomy diminished the nephrotoxicity of A. virosa in male mice and caused changes in the localization of renal lesions.

The effect of furosemide on the renal damage induced by toxic mushroom Cortinarius speciosissimus in the rat.

The effect of furosemide on the renal damage induced by the toxic mushroom Cortinarius speciosissimus was studied in female rats. Furosemide (50 mg/kg s.c.) was given 15 min before the mushroom administration (250 mg dried mushroom/kg body weight p.o.). It was observed that furosemide clearly increased the tubular damage induced by C. speciosissimus. In contrast, furosemide had no effect on the inflammation induced by this toxic mushroom.

Effects of drugs on mushroom poisoning induced in the rat by Cortinarius speciosissimus.

The effect of phenobarbital and phenylbutazone treatment on the renal damage induced by the toxic mushroom Cortinarius speciosissimus was studied in female rats. Phenobarbital sodium was given in drinking water (0.05% solution) for 11 days prior to the administration of mushroom. Phenylbutazone was given s.c. in doses of 50 and 100 mg/kg 1 h before the mushroom administration. Homogenized mushroom was given orally by stomach tube at a dose of 250 mg dried mushroom/kg body weight. It was found that the phenobarbital treatment strongly increased the damage induced by C. speciosissimus in the tubules of the kidney cortex but had no effect on the inflammation in the renal outer medullary zone induced by this toxic mushroom. Phenylbutazone treatment had no effect on the renal damage induced by C. speciosissimus.

Effect of hyperlipidaemic diet and clofibrate treatment on rat erythrocyte lipids.

Lipids of rat plasma and erythrocytes were analysed during hyperlipidaemic diet and clofibrate treatment. The diet increased the plasma cholesterol and phospholipid concentrations after 3 weeks' lipid feeding. Clofibrate in a dose of 200 mg/kg body weight did not inhibit the increase in plasma cholesterol and phospholipid contents, but significantly decreased the concentration of plasma triglycerides. The lipid diet slightly increased the erythrocyte cholesterol and phospholipid concentrations without affecting the red cell morphology or reticulocytosis. After 1 week's treatment, clofibrate in a dose of 200 mg/kg body weight caused a 2-fold increase in the cholesterol content and a rise in the cholesterol-phospholipid ratio of red blood cells of rats fed the hyperlipidaemic diet. These results suggest that the erythrocyte cell membrane can increase its cholesterol content and possibly play a role in cholesterol transport.