Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter found in free-flying peregrine falcons (Falco peregrinus) in Sweden

Rare species with small population sizes are vulnerable to perturbations such as disease, inbreeding, or random events. The threat arising from microbial pathogens could be large and other species could act as reservoirs for pathogens. We report finding three enteric bacterial species, Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter, in nestling free-flying peregrine falcons (Falco peregrinus) in Sweden in 2000. Campylobacter jejuni isolates exhibited marked genetic similarities to an isolate from a human, providing a possible association between a human-associated strain of this bacterium and peregrine falcons.     

Systemic and regional hemodynamic effects of angiotensin-(1-7) in rats

The systemic and regional hemodynamics effects of ANG-(1-7) were examined in urethane-anesthetized rats. The blood flow distribution (kidneys, skin, mesentery, lungs, spleen, brain, muscle, and adrenals), cardiac output, and total peripheral resistance were investigated by using fluorescent microspheres. Blood pressure and heart rate were recorded from the brachial artery. ANG-(1-7) infusion (110 fmol x min(-1) x 10 min(-1) iv) significantly increased blood flow to the kidney (5.10 +/- 1.07 to 8.30 +/- 0.97 ml x min(-1) x g(-1)), mesentery (0.73 +/- 0.16 to 1.17 +/- 0.49 ml x min(-1) x g(-1)), brain (1.32 +/- 0.44 to 2.18 +/- 0.85 ml x min(-1) x g(-1)), and skin (0.07 +/- 0.02 to 0.18 +/- 0.07 ml x min(-1) x g(-1)) and the vascular conductance in these organs. ANG-(1-7) also produced a significant increase in cardiac index (30%) and a decrease in total peripheral resistance (2.90 +/- 0.55 to 2.15 +/- 0.28 mmHg x ml(-1) x min x 100 g). Blood flow to the spleen, muscle, lungs, and adrenals, as well as the blood pressure and heart rate, were not altered by the ANG-(1-7) infusion. The selective ANG-(1-7) antagonist A-779 reduced the blood flow in renal, cerebral, mesenteric, and cutaneous beds and blocked the ANG-(1-7)-induced vasodilatation in the kidney, mesentery, and skin, suggesting a significant role of endogenous ANG-(1-7) in these territories. The effects of ANG-(1-7) on the cerebral blood flow, cardiac index, systolic volume, and total peripheral resistance were partially attenuated by A-779. A high dose of ANG-(1-7) (11 pmol x min(-1) x 10 min(-1)) caused an opposite effect of that produced by the low dose. Our results show for the first time that ANG-(1-7) has a previously unsuspected potent effect in the blood flow distribution and systemic hemodynamics.     

Genetic relationships in the peregrine falcon (Falco peregrinus) analysed by microsatellite DNA markers

Microsatellite DNA markers were developed from a peregrine falcon (Falco peregrinus) and genetic relationships among peregrine falcons in southern Norway were analysed using the markers. The genomic DNA library was screened for the presence of dinucleotide microsatellite repeats. Twelve loci revealed polymorphism through the initial analysis of 24 unrelated peregrine falcons, and Mendelian inheritance was confirmed in two peregrine falcon families bred in captivity. The estimated mean probability of identical genotypes in two unrelated individuals was 3 x 10-8, and the combined exclusion probability for parentage testing was 0.99 and 0.94 for one or both parents unknown, respectively. The markers were used to investigate the parentage of peregrine broods from the same nest site from different breeding seasons, and subsequently the nest-site fidelity of the breeding peregrines. High nest-site fidelity was found by studying pairwise comparisons of relatedness (rxy) estimates among chicks at six nest sites from three different breeding seasons. Cross-species amplifications showed that most loci also appeared to amplify polymorphic products in the gyrfalcon (F. rusticolus), merlin (F. columbarius), hobby (F. subbuteo) and kestrel (F. tinnunculus), demonstrating that the loci will provide powerful genetic markers in these falcons too.     

Renal function and fractional clearances of American river otters (Lutra canadensis)

The finely lobulated kidneys of American river otters (Lutra canadensis) are not visualized on plain abdominal radiographs. Similar values for blood urea nitrogen (BUN), creatinine, and uric acid were obtained on different analytical systems used in 1984 and 1985. The mean +/- SD for measured plasma osmolalities (309.80 +/- 8.86 mOsmol/kg) of otters in 1985 was significantly (P less than 0.01) less than that of calculated serum osmolalities in the same 1985 specimens (321.61 +/- 5.64 mOsmol/kg) and in 1984 specimens (322.20 +/- 7.16 mOsmol/kg). Urine specific gravities and osmolalities were highly correlated (r = 0.92). On routine urinalysis, protein and bilirubin were frequent chemical findings, and urobilinogen was present in all urine samples. White and red blood cells and epithelial cells were frequent findings on urine microscopic examinations. Proteus mirabilis was cultured from four of four female otters with genitourinary infections. The mean +/- SD creatinine values for paired serum and urine samples (n = 13) were serum creatinine (Scr) 0.66 +/- 0.09 mg/dl and urine creatinine (Ucr) 186.9 +/- 55.6 mg/dl. Corresponding values for serum electrolytes (Se) and urine electrolytes (Ue) yielded mean +/- SD calculated renal fractional clearances (FC = Ue/Se x Scr/Ucr) of sodium 9.65 +/- 5.81 x 10(-4), potassium 4.15 +/- 2.01 x 10(-2), chloride 10.81 +/- 5.33 x 10(-4), calcium 4.52 +/- 4.46 x 10(-3), and phosphate 6.58 +/- 3.44 x 10(-3).     

Effects of diets containing gossypol on reproductive capacity of rainbow trout (Oncorhynchus mykiss)

We evaluated five practical diets in which 0%, 25%, 50%, 75%, and 100% (dietary treatments 1-5) of fish meal protein was replaced by solvent-extracted cottonseed meal protein. Adult rainbow trout (initial average weight 247 +/- 8 g) were fed the diets over a period of 131 days during which a general 2-fold body weight increase occurred. The total diet gossypol concentration (free and protein-bound) showed a gradual increase with increased cottonseed meal substitution. Blood samples were collected on Days 0, 64, 112, and 131 for hematological and steroid hormone determination in plasma of males and females. Hemoglobin content was significantly reduced in fish from treatment 5 (7.9 +/- 0.3 g/dl) in comparison to treatments 1-3 (10.3-10.9 g/dl). After 112 and 131 days of feeding, testis weights, concentrations of testosterone, and 11-ketotestosterone were elevated in fish from dietary treatments 2 and 3 in comparison to control and diets 4 and 5. On Day 71, sperm were collected from 6 fish per dietary treatment to assess sperm quality. No significant differences in sperm concentrations (7.2-9.8 x 10(9)/ml), motility (78-89%), and standardized (300 x 10(5) sperm/egg) fertilizing ability (18.9-22.6% hatched embryos) were found. Total gossypol concentrations in blood plasma differed significantly among treatments, and the levels were among the highest ever recorded in animals fed cottonseed-supplemented diets (2.9 +/- 0.2, 11.7 +/- 4.1, 21.7 +/- 1.4, and 29.9 +/- 3.9 microg/ml, for treatments 2-5, respectively). The major portion of gossypol in blood plasma was protein-bound (81-93%). This was in contrast to minute amounts of gossypol present in seminal plasma, mostly in free form (0.02-0.18 microg/ml), which indicates the presence of a barrier between general circulation and the testis with respect to gossypol distribution in lower vertebrates. Thus, the reproductive parameters of male rainbow trout examined in this study were not significantly affected by feeding cottonseed meal for 131 days.     

Distribution and function of muscarinic receptor subtypes in the ovine submandibular gland.

The effects of muscarinic receptor antagonists on responses to electrical stimulation of the chorda-lingual nerve were determined in pentobarbitone-anesthetized sheep and correlated to the morphology of tissue specimens. Stimulation at 2 Hz continuously, or in bursts of 1 s at 20 Hz every 10 s, for 10 min induced similar submandibular fluid responses (19 +/- 3 vs. 21 +/- 3 microl x min(-1) x g gland(-1)), whereas vasodilatation was greater during stimulation in bursts (-52 +/- 4 vs. -43 +/- 5%; P < 0.01). Continuous stimulation at 8 Hz induced substantially greater responses (66 +/- 9 microl x min(-1) x g gland(-1) and -77 +/- 3%). While atropine (0.5 mg/kg iv) abolished the secretory response at 2 and 20 Hz (1:10 s), a small response persisted at 8 Hz (<5%). The "M1-selective" antagonist pirenzepine (40 microg/kg iv) reduced the fluid response at all frequencies tested (P < 0.05-0.01), most conspicuously at 2 Hz (reduced by 69%). Methoctramine ("M2/M4-selective"; 100 microg/kg iv; n = 5) had no effect on fluid or the vascular responses but increased the protein output at 2 (+90%, P < 0.05) and 8 Hz (+45%, P < 0.05). The immunoblotting showed distinct bands for muscarinic M1, M3, M4, and M5 receptors, and immunohistochemistry showed muscarinic M1 and M3 receptors to occur in the parenchyma. Thus muscarinic M1 receptors contribute to the secretory response to parasympathetic stimulation but have little effect on the vasodilatation in the ovine submandibular gland. Increased transmitter release caused by blockade of neuronal inhibitory receptors of the M4 subtype would explain the increase in protein output.     

Physiological characterization of Dunaliella sp. (Chlorophyta, Volvocales) from Yucatan, Mexico

Physiological responses of Dunaliella salina and Dunaliella viridis, isolated from solar saltworks on the Yucatan Peninsula, were studied. Optimal growth temperature for D. salina was 22 degrees C (3.06 x 10(6) cells mL(-1)) and 26 degrees C for D. viridis (4.04 x 10(6)cells mL(-1)). Total carotenoid content in D. salina increased with temperature to a maximum of 35.14 pg cell(-1) at 38 degrees C. Dunaliella salina alpha-carotene and beta-carotene content was 0.083+/-0.003 and 0.598+/-0.020 mg 100g dry wt(-1) respectively, whereas lower values were found in D. viridis cultured under same experimental conditions (0.018+/-0.002 and 0.136+/-0.012 mg 100g dry wt(-1) respectively). The highest specific growth rate in D. salina was obtained at 10% NaCl (0.28 d(-1)), while its cell volume increased from 524 to 2066.93 microm(3) when cultured from 10% to 35% NaCl. Maximum photosynthetic rates were attained when increasing from optimal growing temperature to 30 degrees C for D. viridis (108 n mol O(2)microg chl alpha h(-1)) and D. salina (139 n mol O(2)microg chl alpha h(-1)). Photosynthetic responses to temperature variations indicated physiological adjustments in both species, with higher acclimation in D. salina. Evaluation of physiological attributes of these species will be used for to carry out mass cultivation.     

Effect of obesity on erythrocyte count and hemoglobin levels in Libyan diabetic patients

Fasting blood glucose, erythrocyte count and hemoglobin levels of obese and nonobese Libyan diabetic women were determined. The mean values of fasting blood glucose, erythrocyte count and hemoglobin of obese diabetic women were 209.55 +/- 8.85 mg/dl, 4.986 +/- 0.04 X 10(6)/mm3 and 14.51 +/- 0.18 g/dl. The respective values for nonobese diabetic women were 243.47 +/- 12.56 mg/dl, 4.865 +/- 0.06 X 10(6)/mm3 and 14.31 +/- 0.19 g/dl. The mean values of the three variables of obese patients were significantly different from those of the nonobese patients. Statistically significant correlations were found between fasting blood glucose levels and erythrocyte count, and hemoglobin levels in both obese and nonobese patients. The levels of erythrocyte count and hemoglobin of obese patients were higher than those of their nonobese counterparts. This elevation was attributed to the effect of obesity. It is suggested that regulation of body weight should be considered an essential step in the management of diabetes.     

Role of endogenous opioids in ischemic preconditioning but not in short-term hibernation in pigs

Endogenous opioids are involved in ischemic preconditioning (IP) in several species. Whether or not opioids are important for IP and short-term myocardial hibernation (STMH) in pigs is currently unknown. In 34 enflurane-anesthetized pigs, the left anterior descending coronary artery was flow constantly perfused. Subendocardial blood flow (Endo), infarct size (IS; percent area at risk), and the free energy change of ATP hydrolysis (DeltaG) were determined. After 90-min severe ischemia and 120-min reperfusion, IS averaged 28.3 +/- 5.4% (means +/- SE) (n = 8; Endo: 0.047 +/- 0.009 ml. min(-1) x g(-1)). IP by 10-min ischemia and 15-min reperfusion reduced IS to 9.9 +/- 3.8% (P < 0.05, n = 8; Endo: 0.044 +/- 0.009 ml. min(-1) x g(-1)). After naloxone (1 mg/kg iv followed by 2 microg x kg(-1) x min(-1)), IS averaged 25.8 +/- 7.0% (n = 6; Endo: 0.039 +/- 0.008 ml x min(-1) x g(-1)) without and 24.7 +/- 4.7% (n = 6; Endo: 0.044 +/- 0.006 ml x min(-1) x g(-1)) with IP. At 5-min moderate ischemia in the presence of naloxone, Endo decreased from 0.90 +/- 0.07 to 0.28 +/- 0.03 ml x min(-1) x g(-1)and DeltaG decreased from -58.6 +/- 1.0 to -52.6 +/- 0.4 kJ/mol. Prolongation of ischemia to 90 min did not alter Endo, but DeltaG recovered toward control values (57.7 +/- 1.1 kJ/mol), and the myocardium remained viable. These responses are identical to those of nonnaloxone-treated pigs. Endogenous opioids are involved in IP but not in STMH in pigs.     

Hyperglycemia reduces coronary collateral blood flow through a nitric oxide-mediated mechanism

We tested the hypothesis that hyperglycemia alters retrograde coronary collateral blood flow by a nitric oxide-mediated mechanism in a canine Ameriod constrictor model of enhanced collateral development. Administration of 15% dextrose to increase blood glucose concentration to 400 or 600 mg/dl decreased retrograde blood flow through the left anterior descending coronary artery to 78 +/- 9 and 82 +/- 8% of baseline values, respectively. In contrast, saline or L-arginine (400 mg x kg(-1) x h(-1)) had no effect on retrograde flow. Coronary hypoperfusion and 1 h of reperfusion decreased retrograde blood flow similarly in saline- or L-arginine-treated dogs (76 +/- 11 and 89 +/- 4% of baseline, respectively), but these decreases were more pronounced in hyperglycemic dogs (47 +/- 10%). L-arginine prevented decreases in retrograde coronary collateral blood flow during hyperglycemia (100 +/- 5 and 95 +/- 6% of baseline at blood glucose concentrations of 400 and 600 mg/dl, respectively) and after coronary hypoperfusion and reperfusion (84 +/- 14%). The results suggest that hyperglycemia decreases retrograde coronary collateral blood flow by adversely affecting nitric oxide availability.     

A defect in glucose-induced dissociation of glucokinase from the regulatory protein in Zucker diabetic fatty rats in the early stage of diabetes

Effect of stimulation of glucokinase (GK) export from the nucleus by small amounts of sorbitol on hepatic glucose flux in response to elevated plasma glucose was examined in 6-h fasted Zucker diabetic fatty rats at 10 wk of age. Under basal conditions, plasma glucose, insulin, and glucagon were approximately 8 mM, 2,000 pmol/l, and 60 ng/l, respectively. Endogenous glucose production (EGP) was 44 +/- 4 micromol x kg(-1) x min(-1). When plasma glucose was raised to approximately 17 mM, GK was still predominantly localized with its inhibitory protein in the nucleus. EGP was not suppressed. When sorbitol was infused at 5.6 and 16.7 micromol x kg(-1) x min(-1), along with the increase in plasma glucose, GK was exported to the cytoplasm. EGP (23 +/- 19 and 12 +/- 5 micromol x kg(-1) x min(-1)) was suppressed without a decrease in glucose 6-phosphatase flux (145 +/- 23 and 126 +/- 16 vs. 122 +/- 10 micromol x kg(-1) x min(-1) without sorbitol) but increased in glucose phosphorylation as indicated by increases in glucose recycling (122 +/- 17 and 114 +/- 19 vs. 71 +/- 11 microl x kg(-1) x min(-1)), glucose-6-phosphate content (254 +/- 32 and 260 +/- 35 vs. 188 +/- 20 nmol/g liver), fractional contribution of plasma glucose to uridine 5'-diphosphate-glucose flux (43 +/- 8 and 42 +/- 8 vs. 27 +/- 6%), and glycogen synthesis from plasma glucose (20 +/- 4 and 22 +/- 5 vs. 9 +/- 4 mumol glucose/g liver). The decreased glucose effectiveness to suppress EGP and stimulate hepatic glucose uptake may result from failure of the sugar to activate GK by stimulating the translocation of the enzyme.     

Effects of psyllium hydrophilic mucilloid on LDL-cholesterol and bile acid synthesis in hypercholesterolemic men.

The goal of the current study was to determine the mechanism of the hypocholesterolemic effect of psyllium using a randomized, double-blind, crossover design. Twenty males (age 44 +/- 4 yr, weight 79 +/- 10 kg) with moderate hypercholesterolemia (total 265 +/- 17 mg/dl, low density lipoprotein (LDL) 184 +/- 15 mg/dl) were studied at baseline (B) and after randomization to receive a 40-day course of 15 g/day of either psyllium (Ps) or placebo (Pl) (cellulose). After a washout period (11 +/- 2 days), subjects were crossed over to the other fiber treatment for an additional 40 days and restudied. Intestinal cholesterol absorption, cholesterol synthesis in isolated peripheral blood mononuclear cells, bile acid kinetics, gallbladder motility, and intestinal transit were measured at each study period. Psyllium lowered LDL cholesterol (x:184 (B), 169 (Ps), and 179 (Pl) mg/dl; Ps vs. B,Pl: P less than 0.004, P less than 0.02), decreased relative cholesterol absorption (x:51 (B), 45 (Ps), and 49 (Pl) %; Ps vs. B,Pl: P less than 0.03, P less than 0.03), did not alter absolute cholesterol absorption, and increased the fractional turnover of both chenodeoxycholic acid (x:0.176 (B), 0.203 (Ps), and 0.170 (Pl) day-1; Ps vs. B,Pl: P less than 0.0001, P less than 0.01) and cholic acid (x:0.303 (B), 0.411 (Ps), and 0.301 (Pl) d-1; Ps vs. B, Pl: P less than 0.006, P less than 0.002). Bile acid synthesis increased in subjects whose LDL cholesterol was lowered by more than 10% (Ps vs. B: 1304 +/- 489 vs 992 +/- 307 mumol/day, P less than 0.006; Ps vs. PI: 1304 +/- 489 vs. 914 +/- 321 mumol/day, P less than 0.0002). We conclude that psyllium lowers LDL cholesterol primarily via stimulation of bile acid synthesis.     

Inhibition of nitric oxide synthase enhances superoxide activity in canine kidney

To evaluate the role of a potential interaction between superoxide anion (O(2)(-)) and nitric oxide (NO) in regulating kidney function, we examined the renal responses to intra-arterial infusion of a superoxide dismutase mimetic, tempol (0.5 mg.kg(-1).min(-1)), in anesthetized dogs treated with or without NO synthase inhibitor, N(omega)-nitro-l-arginine (NLA; 50 microg.kg(-1).min(-1)). In one group of dogs (n = 10), tempol infusion alone for 30 min before NLA infusion did not cause any significant changes in renal blood flow (RBF; 5.2 +/- 0.4 to 5.0 +/- 0.4 ml.min(-1).g(-1)), glomerular filtration rate (GFR; 0.79 +/- 0.04 to 0.77 +/- 0.04 ml.min(-1).g(-1)), urine flow (V; 13.6 +/- 2.1 to 13.9 +/- 2.5 microl.min(-1).g(-1)), or sodium excretion (U(Na)V; 2.4 +/- 0.3 to 2.2 +/- 0.3 micromol.min(-1).g(-1)). Interestingly, when tempol was infused in another group of dogs (n = 12) pretreated with NLA, it caused increases in V (4.4 +/- 0.4 to 9.7 +/- 1.4 microl.min(-1).g(-1)) and in U(Na)V (0.7 +/- 0.1 to 1.3 +/- 0.2 micromol.min(-1).g(-1)) without affecting RBF or GFR. Although NO inhibition caused usual qualitative responses in both groups of dogs, the antidiuretic (47 +/- 5 vs. 26 +/- 4%) and antinatriuretic (67 +/- 4 vs. 45 +/- 11%) responses to NLA were seen much less in dogs pretreated with tempol. NLA infusion alone increased urinary excretion of 8-isoprostane (13.9 +/- 2.7 to 22.8 +/- 3.6 pg.min(-1).g(-1); n = 7), which returned to the control levels (11.6 +/- 3.4 pg.min(-1).g(-1)) during coadministration of tempol. These data suggest that NO synthase inhibition causes enhancement of endogenous O(2)(-) levels and support the hypothesis that NO plays a protective role against the actions of O(2)(-) in the kidney.     

Maternal metabolic abnormalities in twin-to-twin transfusion syndrome at mid-pregnancy.

We report abnormal maternal laboratory parameters in twin-to-twin transfusion syndrome (TTTS) at mid-pregnancy. A retrospective chart review was undertaken of 109 patients with TTTS evaluated for placental laser surgery. Complete blood count (CBC), blood type and Rh factor, urine analysis and serum chemistry panel were obtained preoperatively, with the CBC and serum albumin repeated on the first postoperative day. The mean gestational age was 21.2+/-1.7 weeks. Initial abnormal values included hematocrit (32.1+/-3.0%), hemoglobin (11.0+/-1.03 g/dl), serum magnesium (1.71+/-0.17 mg/dl), total protein (6.08+/-0.55 g/dl) and albumin (3.06+/-0.34 g/dl). Despite minimal blood loss and conservative fluid replacement mean hematocrit, hemoglobin, and albumin were 27.3+/-2.74%, 9.3+/-0.94 g/dl and 2.56+/-0.23 g/dl, respectively on postoperative day one. Weight gain (8.0+/-5.5 lb.) and low urinary output were characteristic peri-operative events. Maternal hypoproteinemia and anemia occur in TTTS at mid-pregnancy. This may contribute independently to amniotic fluid production rates in the fetuses, and explain in part the maternal sensitivity to intravenous fluids in multiple pregnancy.     

Modeling the blood lactate kinetics at maximal short-term exercise conditions in children, adolescents, and adults.

Whether age-related differences in blood lactate concentrations (BLC) reflect specific BLC kinetics was analyzed in 15 prepubescent boys (age 12.0 +/- 0.6 yr, height 1.54 +/- 0.06 m, body mass 40.0 +/- 5.2 kg), 12 adolescents (16.3 +/- 0.7 yr, 1.83 +/- 0.07 m, 68.2 +/- 7.5 kg), and 12 adults (27.2 +/- 4.5 yr, 1.83 +/- 0.06 m, 81.6 +/- 6.9 kg) by use of a biexponential four-parameter kinetics model under Wingate Anaerobic Test conditions. The model predicts the lactate generated in the extravasal compartment (A), invasion (k(1)), and evasion (k(2)) of lactate into and out of the blood compartment, the BLC maximum (BLC(max)), and corresponding time (TBLC(max)). BLC(max) and TBLC(max) were lower (P < 0.05) in boys (BLC(max) 10.2 +/- 1.3 mmol/l, TBLC(max) 4.1 +/- 0.4 min) than in adolescents (12.7 +/- 1.0 mmol/l, 5.5 +/- 0.7 min) and adults (13.7 +/- 1.4 mmol/l, 5.7 +/- 1.1 min). No differences were found in A related to the muscle mass (A(MM)) and k(1) between boys (A(MM): 22.8 +/- 2.7 mmol/l, k(1): 0.865 +/- 0.115 min(-1)), adolescents (22.7 +/- 1.3 mmol/l, 0.692 +/- 0.221 min(-1)), and adults (24.7 +/- 2.8 mmol/l, 0.687 +/- 0.287 min(-1)). The k(2) was higher (P < 0.01) in boys (2.87 10(-2) +/- 0.75 10(-2) min(-1)) than in adolescents (2.03 x 10(-2) +/- 0.89 x 10(-2) min(-1)) and adults (1.99 x 10(-2) +/- 0.93 x 10(-2) min(-1)). Age-related differences in the BLC kinetics are unlikely to reflect differences in muscular lactate or lactate invasion but partly faster elimination out of the blood compartment.     

Identification of differentially expressed genes in parasitic phase Miamiensis avidus (Ciliophora: Scuticociliatia) using suppression subtractive hybridization

A multiplex (m-)PCR-based protocol was designed for the simultaneous detection of the main marine bacterial pathogens in Chilean salmon farms: Streptococcus phocae, Aeromonas salmonicida, Vibrio anguillarum and Piscirickettsia salmonis. Each of the 4 oligonucleotide primer pairs exclusively amplified the target gene of the specific bacterial pathogen. The detection limit of the m-PCR using purified total bacterial DNA was 50 pg microl(-1) for V anguillarum, 500 fg microl(-1) for P. salmonis, and 5 pg microl(-1) for S. phocae and A. salmonicida. This corresponded to average limits in the m-PCR sensitivity of 3.69 x 10(5) CFU ml(-1) of V anguillarum, 1.26 x 10(4) CFU m(-1) of S. phocae, and 5.33 x 10(4) CFU ml(-1) of A. salmonicida, while the detection limits for the spiked fish tissues, regardless of the sample (spleen, kidney, liver or muscle) were 2.64 +/- 0.54 x 10(7) CFU g(-1) for V. anguillarum, 9.03 +/- 1.84 x 10(5) CFU g(-1) for S. phocae, 3.8 +/- 0.78 x 10(3) CFU mg(-1) for A. salmonicida and 100 P. salmonis cells. However, high amounts of DNA from 3 bacterial species had a reduction of -1 log-unit on the amplification sensitivity of S. phocae or A. salmonicida when these were present in lower concentration in the multiplex reaction. The assay described in this study is a rapid, sensitive and efficient tool to detect the presence of S. phocae, A. salmonicida, V. anguillarum and P. salmonis simultaneously from pure cultures and tissues from clinically diseased fish. Therefore, it may be a useful alternative to culture-based methods for the diagnosis of infections in fish obtained from Chilean salmon farms.     

Down-Regulation of AMPA Glutamate Receptors Reduces Cerebrocortical Metabolic Response to Stimulation

We tested the hypothesis that chronic stimulation of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate) glutamate receptors with an agonist causes down-regulation of the receptor protein and a decrement in basal and/or stimulated cerebral O2 consumption. Male Wistar rats were intradurally infused with 10 microM AMPA by an osmotic pump at a rate of 1 microl/h for 6 days. As a result, the specific binding of (S)-[3H]-5-fluorowillardiine to AMPA receptors in the cerebral cortex decreased 46% from 2.7 +/- 0.3 to 1.5 +/- 0.6 (density units). Under isoflurane anesthesia and after topical stimulation to the right cerebral cortex with 10(-3) M AMPA, cerebral blood flow (14C-iodoantipyrine method) and O2 consumption (cryomicrospectrophotometrically determined) were determined in control and down-regulated rats. Down-regulation of AMPA receptors did not alter basal O2 consumption. In control, after agonist stimulation, the O2 consumption in the ipsilateral cortex increased by 34%, (4.7 +/- 0.5 ml O2 x min(-1) x 100 g(-1) compared to 3.5 +/- 0.4 in the contralateral cortex). In the down-regulated rats, the O2 consumption did not significantly increase (4.0 +/- 1.5 ml O2 x min(-1) x 100 g(-1) compared to 3.3 +/- 1.7 in the contralateral cortex) after AMPA. In conclusion, following chronic simulation, AMPA receptors underwent down-regulation, but such down-regulation did not alter basal cerebrocortical blood flow or O2 consumption. AMPA down-regulation reduced the agonist stimulated increase in cortical O2 consumption.     

Brain-to-blood efflux transport of estrone-3-sulfate at the blood-brain barrier in rats

Efflux transport of estrogens such as estrone-3-sulfate (E1S), and estrone (E1) across the blood-brain barrier (BBB) was evaluated using the Brain Efflux Index (BEI) method. The apparent BBB efflux rate constant (Keff) of [3H]E1S, and [3H]E1 was 6.63 x 10(-2) +/- 0.77 x 10(-2) min(-1), and 6.91 x 10(-2) +/- 1.23 x 10(-2) min(-1), respectively. The efflux transport of [3H]E1S from brain across the BBB was a saturable process with Michaelis constant (Km) of 96.0 +/- 34.4 microM and 93.4 +/- 22.0 microM estimated by two different methods. By determining [3H]E1S metabolites using high performance liquid chromatography (HPLC) after intracerebral injection, significant amounts of [3H]E1S were found in the jugular venous plasma, providing direct evidence that most of [3H]E1S is transported from brain across the BBB in intact form. To compare the apparent efflux clearance across the BBB of E1S with that of E1, the brain distribution volume of E1S and E1 was estimated using the brain slice uptake method. The apparent efflux clearance of [3H]E1S was determined to be 74.9 +/- 3.8 microl/(min x g brain) due to the distribution volume of 1.13 +/- 0.06 ml/g brain. By contrast, the apparent efflux clearance of E1 was more than 227 +/- 3 microl/(min x g brain), since the distribution volume of [3H]E1 at 60 min was 3.28 +/- 0.13 ml/g. The E1S efflux transport process was inhibited by more than 40% by coadministration of bile acids (taurocholate, and cholate), and organic anions (sulfobromophthalein, and probenecid), whereas other organic anions did not affect the E1S efflux transport. The [3H]E1S efflux was significantly reduced by 48.6% after preadministration of 5 mM dehydroepiandrosterone sulfate. These results suggest that E1S is transported from brain to the circulating blood across the BBB via a carrier-mediated efflux transport system.     

Attenuated renovascular constrictor responses to angiotensin II in adenosine 1 receptor knockout mice

In the present experiments we examined the renovascular constrictor effects of ANG II in the chronic and complete absence of A1 adenosine receptors (A1AR) using mice with targeted deletion of the A1AR gene. Glomerular filtration rate (GFR) was not different between A1AR +/+ and A1AR -/- mice under control conditions (450.5 +/- 60 vs. 475.2 +/- 62.5 microl/min) but fell significantly less in A1AR -/- mice during infusion of ANG II at 1.5 ng/min (A1AR +/+: 242 +/- 32.5 microl/min, A1AR -/-: 371 +/- 42 microl/min; P = 0.03). Bolus injection of 1, 10, and 100 ng of ANG II reduced renal blood flow and increased renal vascular resistance significantly more in A1AR +/+ than in A1AR -/- mice. Perfused afferent arterioles isolated from A1AR +/+ mice constricted in response to bath ANG II with an EC50 of 1.5 +/- 0.4 x 10(-10) mol/l, whereas a right shift in the dose-response relationship with an EC50 of 7.3 +/- 1.2 x 10(-10) mol/l (P < 0.05) was obtained in arterioles from A1AR -/- mice (P < 0.05). The expression of AT1A receptor mRNA was not different in kidney RNA from A1AR +/+ or A1AR -/- mice. We conclude that chronic A1AR deficiency diminishes the effectiveness of ANG II to constrict renal resistance vessels and to reduce GFR.