Contrasting associations between breeding coloration and parasitism of male Arctic charr relate to parasite species and life cycle stage.

Conspicuous carotenoid ornamentation is considered a signal of individual "quality" and one of the most intensely studied traits found to co-vary with parasitism. Since it has been suggested that only "high quality" individuals have enough resources to express excessive sexual ornaments and resist parasites, current theory struggles to explain cases where the brightest individuals carry the most parasites. Surprisingly little emphasis has been put on the contrasting routes to fitness utilized by different parasite species inhabiting the same host. Using Arctic charr (Salvelinus alpinus) as model species, we hypothesized that skin redness and allocation of carotenoids between skin and muscle (redness ratio) will be positively and negatively associated with parasites using the fish as an intermediate and final host, respectively. Both pigment parameters were indeed positively associated with abundances of parasites awaiting trophic transmission (Diplostomum sp. and Diphyllobothrium spp.) and negatively associated with the abundance of adult Eubothrium salvelini tapeworms. These empirical data demonstrate that contrasting associations between carotenoid coloration and parasite intensities relates to the specific premises of different parasite species and life cycle stages.

Are hybrids between Atlantic salmon and brown trout suitable long-term hosts of Gyrodactylus salaris during winter?

The monogenean parasite Gyrodactylus salaris poses serious threats to many Atlantic salmon populations and presents many conservation and management questions/foci and challenges. It is therefore critical to identify potential vectors for infection. To test whether hybrids of native Atlantic salmon (Salmo salar) × brown trout (Salmo trutta) are suitable as reservoir hosts for G. salaris during winter, infected hybrid parr were released into a natural subarctic brook in the autumn. Six months later, 23.9% of the pit-tagged fish were recaptured. During the experimental period, the hybrids had a sixfold increase in mean intensity of G. salaris, while the prevalence decreased from 81% to 35%. There was high interindividual hybrid variability in susceptibility to infections. The maximum infrapopulation growth rate (0.018 day-1 ) of G. salaris throughout the winter was comparable to earlier laboratory experiments at similar temperatures. The results confirm that infrapopulations of G. salaris may reproduce on a hybrid population for several generations at low water temperatures (~1 °C). Wild salmon-trout hybrids are undoubtedly susceptible to G. salaris and represent an important reservoir host for the parasite independent of other co-occurring susceptible hosts. Consequently, these hybrids may pose a serious risk for G. salaris transmission to nearby, uninfected rivers by migratory individuals.

Transmission dynamics of the monogenean Gyrodactylus salaris under seminatural conditions.

Tracking individual variation in the dynamics of parasite infections in wild populations is often complicated by lack of knowledge of the epidemiological history of hosts. Whereas the dynamics and development of Gyrodactylus salaris Malmberg, 1957, on Atlantic salmon, Salmo salar L., are known from laboratory studies, knowledge about infection development on individual wild fishes is currently sparse. In this study, the dynamics of an infection of G. salaris on individually marked Atlantic salmon parr was followed in a section of a natural stream. During the 6-week experiment, the prevalence increased from 3.3 to 60.0%, with an average increase in intensity of 4.1% day(-1) . Survival analyses showed an initially high probability (93.6%) of staying uninfected by G. salaris, decreasing significantly to 37% after 6 weeks. The results showed that even at subarctic water temperatures and with an initially low risk of infection, the parasite spread rapidly in the Atlantic salmon population, with the capacity to reach 100% prevalence within a short summer season. The study thus track individual infection trajectories of Atlantic salmon living under near-natural conditions, providing an integration of key population parameters from controlled experiments with the dynamics of the epizootic observed in free-living living populations.

TPA for ischemic stroke in patients ≥80 years.

OBJECTIVE: Although patients >80 years were excluded in RCTs for tPA treatment of acute ischemic stroke (AIS), many centers treat old patients. We wanted to examine whether age ≥80 years is an independent predictor of outcome after tPA. MATERIALS: We included 77 consecutive patients ≥80 years and 83 patients <80 years treated with tPA within 4.5 h after onset of AIS. Baseline variables were analyzed by multiple stepwise logistic regression analyses against three outcomes: symptomatic intracerebral hemorrhage (sICH), death and good functional outcome (mRS, 0-1) at 3-month follow-up. RESULTS: Age ≥80 years was associated with increased risk of sICH (OR, 18.2 [95% CI, 1.0-324.1], P = 0.048), and death (OR, 3.3 [95% CI, 1.2-9.1], P = 0.018), but not with functional outcome at 3 months. Other factors associated with death were longer onset to treatment time (OTT) (OR, 1.007/min increase [95% CI, 1.00-1.015], P = 0.047), higher NIHSS (OR, 1.12 per point increase [95% CI, 1.04-1.19], P = 0.001), and previous stroke (OR, 4.0 [95% CI, 1.2-13.7], P = 0.03). Predictors of good functional outcome were shorter OTT (OR, 0.99 [95% CI, 0.98-1.00], P = 0.02) and lower NIHSS (OR, 0.80 [95% CI, 0.74-0.87] P ≤ 0.001). CONCLUSION: Age ≥80 years might be an independent risk factor for sICH and death the first 3 months after treatment with tPA for AIS, but does not influence the chance of a good functional outcome. We suggest to treat patients over 80 years with tPA, but be cautious if the time from onset (OTT) is long.

Comparative maternal and neonatal effects of halothane and enflurane for cesarean section.

The effects of placental transfer of enflurane and halothane were studied in 81 women undergoing cesarean sections. All patients had rapid sequence induction using thiopental, succinylcholine, and endotracheal intubation. They were then randomly assigned to one of five groups: Group I (n = 16) received N2O and oxygen, Group II (n = 16) N2O, oxygen, and 0.25% halothane, Group III (n = 18) N2O, oxygen, and 0.5% halothane, Group IV (n = 18) N2O, oxygen, and 0.5% enflurane, Group V (n = 13) N2O, oxygen, and 1% enflurane. At delivery, blood was drawn from the maternal artery, umbilical vein and artery for measurement of the halogenated agents using gas chromatography. The neonates were evaluated by Apgar scores, umbilical artery and vein acid base status and the Early Neonatal Neurobehavioral Scores (ENNS) at 2 and 24 h of age. Blood loss and the incidence of maternal awareness were also determined. The umbilical vein to maternal vein ratio was approximately 0.5 and 0.6 for enflurane and halothane, respectively. The umbilical artery to umbilical vein ratio was 0.5 with both agents; higher inspired anesthetic concentrations produced higher blood levels. All neonates had Apgar scores of 8 or more at 5 min with the exception of one neonate in the N2O group. Maternal and neonatal acid base status, blood loss, and ENNS were not affected by the addition of the halogenated agents. Of the patients who had N2O alone, 12% had awareness versus none in the other groups. These data demonstrate that low dose halothane or enflurane decreases the incidence of maternal awareness and does not adversely affect the neonate.

Efficacy of clear antacid prophylaxis in obstetrics.

We studied 33 women scheduled to undergo general anesthesia for cesarean section. Prior to induction of anesthesia, each patient received in a random fashion one of two prophylactic antacids. Group I (n = 17) received 30 ml Gelusil orally and Group II (n = 16) received 30 ml of 0.3 mol/l sodium citrate. After induction of general anesthesia an oro-gastric tube was passed. The amount and pH of the gastric aspirate were measured at the time of delivery and 45 min after delivery "before extubation." Both antacids elevated gastric pH above 3.5 in all patients but one in the Gelusil group. The pH remained elevated 45 min later. It is concluded that 0.3 mol/l sodium citrate is effective as an antacid when given orally prior to induction of anesthesia.

Maternal catecholamines decrease during labor after lumbar epidural anesthesia.

To determine whether epidural anesthesia during labor affects maternal circulating catecholamines, blood samples were obtained from 15 patients at the peak of and immediately after two consecutive painful contractions. A lumbar epidural local anesthetic without epinephrine was then administered. After the onset of analgesia, four blood samples were again drawn. All samples were analyzed by a radioenzymatic assay for epinephrine and norepinephrine concentrations. Before anesthesia, the mean (+/-SEM) plasma epinephrine level was 280 +/- 49 pg/ml, and the mean norepinephrine level was 866 +/- 122 pg/ml. After anesthesia, epinephrine levels decreased 56% (p less than 0.01). Although norepinephrine levels decreased approximately 19%, this reduction was not statistically significant. At the height of a contraction, catecholamine levels did not differ significantly from those occurring between contractions. Lumbar epidural anesthesia during labor reduces maternal epinephrine levels, probably by eliminating the psychological and physical stress associated with painful uterine contractions or by denervating the adrenal medulla. Whatever the mechanism, reducing pain and activity of the sympathetic nervous system should increase uterine blood flow.

Sympathoadrenal activity, maternal, fetal, and neonatal responses after epidural anesthesia in the preeclamptic patient.

This study confirms that preeclamptic patients have higher plasma levels of catecholamine than those of normal patients. It also demonstrates that epidural analgesia when administered to the preeclamptic patient during labor is followed by a significant reduction in the plasma levels of catecholamines without any adverse effects on maternal blood pressure, uterine activity, fetal heart rate, or the neonate.

Maternal, fetal, and neonatal responses after epidural anesthesia with bupivacaine, 2-chloroprocaine, or lidocaine.

The effects of epidural analgesia on fetal heart rate, fetal heart rate variability, uterine activity, maternal blood pressure, newborn Apgar scores, neonatal acid base status, and the early neonatal neurobehavioral status were studied in 150 parturients during labor and delivery. Group I (n = 50) received 0.5% bupivacaine, group II (n = 50) received 2% 2-chloroprocaine, and in group III (n = 50) received 1.5% lidocaine. None of the three local anesthetics used had any significant effect on either base line fetal heart rate, beat-to-beat variability, or uterine activity. In cases in which monitoring of fetal heart rate was both technically satisfactory and continuous, late deceleration patterns were seen in 8 of 42, 0 of 34, and 3 of 47 of the fetuses in group I, II, and III, respectively. The difference in incidence of late deceleration patterns between groups I and II was statistically significant (p less than 0.025). Early neonatal neurobehavioral status did not differ among the three groups of neonates nor did any of the neonates in the three groups score lower than a control group of 20 neonates whose mothers did not receive any analgesia or medications for labor or delivery. It is concluded that epidural anesthesia as administered in this study has no significant effect on the base line fetal heart rate, uterine activity, or neurobehavioral status of the neonate, and that bupivacaine is associated with a higher incidence of what appears to be transient abnormalities of fetal heart rate.

Neonatal neurobehavioral effects of inhalation analgesia for vaginal delivery.

The authors studied the neonatal neurobehavioral effects of nitrous oxide:oxygen and enflurane:oxygen inhalation analgesia for vaginal delivery. Parturients were assigned randomly to receive no inhalation agent (Group 1, n = 21); enflurane, 0.3 to 0.8 per cent, and oxygen (Group 2, n = 22); or nitrous oxide, 30 to 50 per cent, and oxygen (Group 3, n = 18). Infants were tested at 15 min, 2 h, and 24 h of age using the Neurologic and Adaptive Capacity Score (NACS); and at 2 and 24 h using the Early Neonatal Neurobehavioral Scale (ENNS). No significant differences in neurobehavioral status occurred. For all groups, scores tended to be lowest at two hours of age. We conclude that neither enflurane nor nitrous oxide analgesia adversely affects neonatal neurobehavioral status at 15 min, 2 h, or 24 h of age.

Effects of spinal anesthesia on maternal circulating catecholamines.

This study evaluated the effects of spinal anesthesia on maternal circulating catecholamines. Spinal anesthesia was administered in two groups of patients undergoing cesarean section. Nine patients were in labor; 14 were not in labor. Spinal anesthesia was followed by a significant reduction in norepinephrine (NE) in patients in labor (p less than 0.05). No such reduction was observed in the patients not in labor despite sensory levels of the fourth thoracic vertebra--or higher. There were no changes in epinephrine (E) levels in either groups. Ephedrine was administered to seven patients not in labor who developed hypotension. There were no significant changes in either NE or E.

Enflurane analgesia in obstetrics.

The effects of enflurane analgesia (approximately 0.5%) were studied in 55 patients during the second stage of normal vaginal delivery and were compared with effects of nitrous oxide (approximately 40%) in 50 similar patients. The enflurane and oxygen mixture was rated satisfactory by 89% of the mothers and 80% of the anesthesiologists. These ratings did not differ significantly from those for nitrous oxide. Obstetricians, however, rated the enflurane and oxygen mixture superior. The newborns of mothers receiving both agents wee vigorous and comparable when assessed by Apgar scores and cord blood gas tensions. The estimate of blood loss was similar in both groups. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly increased from preanesthetic levels with either agent. There was no biochemical evidence of renal toxicity. In neonates of mothers given enflurane, the mean umbilical cord concentration of serum inorganic fluoride ions was 2.4 +/- 0.2 micromoles/L, a value well below that associated with nephrotoxicity.

Use of glycopyrrolate in the parturient: effect on the maternal and fetal heart and uterine activity.

The effects of intravenous glycopyrrolate on maternal and fetal heart rate, heart rate variability, and maternal electromechanical intervals and blood pressure were evaluated in 20 term parturients in labor. Direct continuous fetal heart rate and intrauterine pressure were monitored via an intrauterine catheter. Maternal heart rate and R-pulse-wave intervals were measured and maternal blood pressure was recorded at 5-minute intervals. There were no significant changes in fetal heart rate or fetal heart rate variability. The maternal heart rate increased in all cases and the electromechanical interval decreased with the onset of maternal tachycardia. There were no significant changes in maternal blood pressure. Uterine activity increased in all cases; however, this increase does not appear to be greater than that expected in uterine activity as labor progresses.