Prior Anesthesia Research Articles

Efficient method for establishing F1 progeny from wild populations of Anopheles mosquitoes

BackgroundThe changing malaria situation in Madagascar requires additional knowledge on the physiology and behaviour of local mosquito vectors. However, the absence of established colonies for several anopheline species present in Madagascar constitutes a limiting factor. To avoid labour intensive work and uncertainty for success of establishing Anopheles colonies from Malagasy species, field collections of blood-fed females and in-tube forced oviposition were combined to reliably produce large numbers of F1 progeny.MethodsBlood-fed females were captured in zebu stables or open zebu parks. Oviposition was induced by enclosing gravid females in eppendorf tubes as initially described for Anopheles funestus. The effect of cold anaesthesia on inducing in-tube forced oviposition and on egg yield was assessed for five Anopheles species, namely Anopheles coustani, An. funestus, Anopheles mascarensis, Anopheles arabiensis and Anopheles squamosus. The production of eggs from in-tube forced oviposition and standard egg laying in cages was compared.ResultsFor the five anopheline species studied, the in-tube forced oviposition method had different efficacy ranging from 35.6 to 71.1% females willing to lay eggs in tubes. Interestingly, prior anaesthesia increased significantly the proportion of ovipositing females for An. mascarensis. Prior anaesthesia has a marginal effect on the number of eggs produced. However, the overall yield in eggs collected using the in-tube forced oviposition method largely exceeds the number of eggs that can be produced by females free to oviposit in cages.ConclusionThe efficiency of the method allowed the production of F1 progeny in numbers sufficiently large for developing detailed analyses of the five species tested, including behavioural studies, insecticide resistance assessment and molecular characterization, as well as vector competence studies. It should be applicable to other anopheline species difficult to colonize.

ASSOCIATION OF MILD COGNITIVE IMPAIRMENT WITH EXPOSURE TO GENERAL ANESTHESIA FOR SURGICAL AND NON-SURGICAL PROCEDURES IN OLMSTED COUNTY, MINNESOTA

Cognitive impairment is often attributed to exposure to general anesthesia and surgery even when the temporal relationship is remote. We had the opportunity to examine the relationship of prior anesthesia and surgery to earliest manifestations of cognitive impairment using a prospective population-based cohort combined with medical record documentation of prior surgical events. The Mayo Clinic Study of Aging (MCSA) is a population-based study of individuals in Olmsted County MN who were age 70-89 years at enrollment beginning in 2004. They have been followed for a median of 4.8 years and standard criteria were used to diagnose incident MCI in the subset of individuals who were cognitively normal at baseline. Exposure to surgery and anesthesia after age 40 years of age was documented by medical record review using the facilities of the Rochester Epidemiology Project's records linkage system for Olmsted County. Thirty one percent (n=536) of 1731 initially cognitively normal individuals developed incident MCI over the period of observation. Exposure to anesthesia was not associated with incident MCI when analyzed as a dichotomous variable (HR=1.07, 95% CI 0.83-1.37) or when multiple exposures were considered. Exposure to anesthesia after age 60 years of age was weakly associated with incident MCI (HR=1.25, 95%CI 1.02-1.55, p=0.04). Overall there was no significant associations between exposure to general anesthesia beginning at age 40 years. Our results do not exclude the possibility of an association with incident MCI of exposure to general anesthesia after age 60, but the latter is confounded by the presence of underlying comorbidities that could be directly linked to dementia risk. Supported by: R01-AG034676, P50-AG16574, U01-AG006786.

Plasma substance P concentrations in patients undergoing general anesthesia: an objective marker associated with postoperative nausea and vomiting.

BackgroundThis study investigated plasma concentrations of substance P (SP) in patients undergoing general anesthesia (GA) and postoperative nausea and vomiting (PONV). This prospective, observational, cohort study included 23 patients who underwent scheduled surgery under general anesthesia. Blood was collected from the radial artery at predetermined time points (15–30 mins prior anesthesia, 15–30 mins after surgery/GA, and 24 h after surgery). PONV, SP concentrations, risk factors, and analgesics used were measured.FindingsNine of 23 patients experienced PONV. In patients without PONV, SP concentrations significantly decreased (P < 0.0001) at the end of surgery/GA, compared to baseline, and recovered at 24 h after surgery/GA (452.9 ± 146.2 vs. 666.9 ± 176.5 vs. 580.7 ± 168.6 pg/mL, respectively), whereas SP levels were unchanged during surgery/GA and increased at 24 hours after surgery (P = 0.020) in patients with PONV (726.1 ± 167.8 vs. 655.8 ± 168.0 vs. 779.7 ± 220.7 pg/mL, respectively).ConclusionsThese finding suggest that SP levels may be utilized as an objective marker for PONV.

Peri-infarct depolarizations during focal ischemia in the awake Spontaneously Hypertensive Rat. Minimizing anesthesia confounds in experimental stroke

Anesthesia profoundly impacts peri-infarct depolarizations (PIDs), but only one prior report has described their monitoring during experimental stroke in awake animals. Since temporal patterns of PID occurrence are model specific, the current study examined PID incidence during focal ischemia in the awake Spontaneously Hypertensive Rat (SHR), and documented the impact of both prior and concurrent isoflurane anesthesia. For awake recordings, electrodes were implanted under isoflurane anesthesia 1day to 5weeks prior to occlusion surgery. Rats were then subjected to permanent or transient (2h) tandem occlusion of the middle cerebral and ipsilateral common carotid arteries, followed by PID monitoring for up to 3days. Comparison perfusion imaging studies evaluated PID-associated hyperemic transients during permanent ischemia under anesthesia at varied intervals following prior isoflurane exposure. Prior anesthesia attenuated PID number at intervals up to 1week, establishing 2weeks as a practical recovery duration following surgical preparation to avoid isoflurane preconditioning effects. PIDs in awake SHR were limited to the first 4h after permanent occlusions. Maintaining anesthesia during this interval reduced PID number, and prolonged their occurrence through several hours following anesthesia termination. Although PID number otherwise correlated with infarct size, PID suppression by anesthesia was not protective in the absence of reperfusion. PIDs persisted up to 36h after transient occlusions. These results differ markedly from the one previous report of such monitoring in awake Sprague–Dawley rats, which found an extended biphasic PID time course during 24h after both permanent and transient filament occlusions. PID occurrence closely reflects the time course of infarct progression in the respective models, and may be more useful than absolute PID number as an index of ongoing pathology.

Anesthesiologist: the patient's perception

Background and objectivesAnesthesia is still a major concern for patients, although the anesthetic complications have decreased significantly. Additionally, the role assigned to the anesthesiologist remains inaccurate. The aim of this study was to evaluate the concerns with anesthesia and assess the patient's knowledge about the anesthesiologist's duties. MethodsProspective study conducted over three months with patients in the preoperative anesthetic visit in a university hospital. Demographic information about the level of education and prior anesthesia was obtained. The knowledge of patients regarding the anesthesiologists’ education was evaluated. Patients’ concerns and anesthesiologist and surgeon responsibilities were classified with a 5-point scale. The analysis was performed with SPSS 21, and p<0.05 was considered statistically significant. ResultsWe included 204 patients, and 135 (66.2%) recognized the anesthesiologist as a specialist physician. Not waking up after surgery and postoperative infection were the main concerns compared to all others (p<0.05). Women expressed more concern than men about not waking up after surgery, nausea and postoperative vomiting, medical problems, and waking up during surgery (p<0.05). Ensure that patients do not wake up during surgery was the anesthesiologist task most recognized, compared to all other (p<0.05). The surgeon was more recognized (p<0.05) than the anesthesiologist in post-operative, antibiotics administration, and blood transfusions pain management. ConclusionsPatients need to be informed about the current safety of anesthesia and the anesthesiologist's functions. The patient involvement will demystify some fears and reassure the confidence in the health system.

Preconditioning cortical lesions reduce the incidence of peri-infarct depolarizations during focal ischemia in the Spontaneously Hypertensive Rat: interaction with prior anesthesia and the impact of hyperglycemia.

The relationship between peri-infarct depolarizations (PIDs) and infarction was investigated in a model of preconditioning by cortical freeze lesions (cryogenic lesions, CL) in the Spontaneously Hypertensive Rat. Small (< 5 mm(3)) lesions produced 24 hours before permanent focal ischemia were protective, without impacting baseline cerebral blood flow (CBF) and metabolism. Prior CL reduced infarct volume, associated with improved penumbral CBF as previously showed for ischemic preconditioning. The brief initial procedure avoided sham effects on infarct volume after subsequent occlusion under brief anesthesia. However, under prolonged isoflurane anesthesia for perfusion monitoring both sham and CL rats showed reduced PID incidence relative to naive animals. This anesthesia effect could be eliminated by using α-chloralose during perfusion imaging. As an additional methodological concern, blood glucose was frequently elevated at the time of the second surgery, reflecting buprenorphine-induced pica and other undefined mechanisms. Even modest hyperglycemia (>10 mmol/L) reduced PID incidence. In normoglycemic animals CL preconditioning reduced PID number by 50%, demonstrating associated effects on PID incidence, penumbral perfusion, and infarct progression. Hyperglycemia suppressed PIDs without affecting the relationship between CBF and infarction. This suggests that the primary effect of preconditioning is to improve penumbral perfusion, which in turn impacts PID incidence and infarct size.

O anestesiologista: a visão do doente

Background and objectivesAnesthesia is still a major concern for patients, although the anesthetic complications have decreased significantly. Additionally, the role assigned to the anesthesiologist remains inaccurate. The aim of this study was to evaluate the concerns with anesthesia and assess the patient's knowledge about the anesthesiologist's duties. MethodsProspective study conducted over three months with patients in the preoperative anesthetic visit in a university hospital. Demographic information about the level of education and prior anesthesia was obtained. The knowledge of patients regarding the anesthesiologists’ education was evaluated. Patients’ concerns and anesthesiologist and surgeon responsibilities were classified with a 5‐point scale. The analysis was performed with SPSS 21, and p<0.05 was considered statistically significant. ResultsWe included 204 patients, and 135 (66.2%) recognized the anesthesiologist as a specialist physician. Not waking up after surgery and postoperative infection were the main concerns compared to all others (p<0.05). Women expressed more concern than men about not waking up after surgery, nausea and postoperative vomiting, medical problems, and waking up during surgery (p<0.05). Ensure that patients do not wake up during surgery was the anesthesiologist task most recognized, compared to all other (p<0.05). The surgeon was more recognized (p<0.05) than the anesthesiologist in post‐operative, antibiotics administration, and blood transfusions pain management. ConclusionsPatients need to be informed about the current safety of anesthesia and the anesthesiologist's functions. The patient involvement will demystify some fears and reassure the confidence in the health system.

The patients' understanding on the status and role of anaesthesiologists.

To evaluate patients' understanding on the status and role of anaesthesiologists. This was a prospective, questionnaire-based cross-sectional study. The interview had three segments which questioned on (i) patients' knowledge of the qualification, training and role of anaesthesiologists, (ii) attitude of patients towards anaesthesia and anaesthesiologists and (iii) the demographic data of patients. Of 384 patients interviewed, 59.4% had prior anaesthesia experience. Most patients (95.6%) knew that anaesthesiologists were medical doctors, but only 27.1% knew the duration of training required to attain this specialist qualification. Patients' awareness of the various anaesthetic responsibilities was 12.2% in managing labour pain, 25.5% in intensive care units, 49.2% in chronic pain and 99.5% in postoperative pain management. During surgery, 73.7% of patients knew that anaesthesiologists were monitoring their vital signs, but only 42.2% thought anaesthesiologists also treated medical problems intraoperatively. Most patients (95.1%) would like to meet their anaesthesiologists prior to the operation and 97.7% want them to inform all possible anaesthesia complications. Our patients' understanding and awareness of the status and roles of anaesthesiologists are still limited and variable. This can be further improved with patient interaction and public education.

Ethical euthanasia and short-term anesthesia of the chick embryo.

Fertilized chicken eggs are suggested as an alternative to mammalian models. The chorioallantoic membrane (CAM) of the chick embryo is widely used for examination of angiogenesis, xenotransplants and for virus production. Unfortunately, it is mostly not taken into account, that the chick embryo's ability to experience pain starts to develop at day 7 of breeding. In our view, this model is only in accordance with the 3 R principles, if an appropriate anesthesia of the chick embryo in potentially painful procedures is provided. Although many experimental approaches are performed on the none-innervated CAM, the euthanasia of the embryo strongly requires a more human technique than the usually used freezing at -20°C, decapitation or in ovo fixation with paraformaldehyde without prior anesthesia. However, protocols regarding feasible and ethical methods for anesthesia and euthanasia of avian embryos are currently not available. Therefore, we established an easy and reliable method for the euthanasia and short-term anesthesia of the chick embryo.

Menthol as anaesthetic for lambari Astyanax altiparanae (Garutti &amp; Britski 2000): attenuation of stress responses

The anaesthetic potential of menthol was evaluated in lambari Astyanax altiparanae by exposing fingerlings to concentrations 50, 100, 150, 200, 250 and 300 mg L 1 and measuring the induction and recovery times to deep anaesthesia, the mortality rates during and 96 h after procedure and after 6 min of continuous exposure. The effect of menthol on stress responses were evaluated by comparing glucose and cortisol levels of juveniles subjected to anaesthesia (50 mg L 1 ), stress (air exposure) or pre-anaesthesia associated to stress. All concentrations induced deep anaesthesia within 0.5 to 1 min, with recovery between 1.83 and 4.16 min, without mortality during the induction or up to 96 h after exposure. Induction time decreased and recovery time increased linearly as the menthol concentration increased. Continuous exposure to 50, 100 and 150 mg L 1 concentrations resulted in mortality rates of 0%, 20% and 80% respectively. Anaesthesia or air exposure increase blood glucose but prior anaesthesia with menthol suppressed the elevation of cortisol caused by stress. Menthol has an anaesthetic effect and attenuates the stress response in lambari and 50 mg L 1 is the most effective concentration for inducing deep anaesthesia in 1.0 min, safe for up to 6 min exposure.

Aprotinin Reduces the Procalcitonin Rise Associated With Complex Cardiac Surgery and Cardiopulmonary Bypass

Aprotinin, a nonspecific serine protease inhibitor, has been primarily used as a haemostatic drug in cardiac surgery with cardio-pulmonary bypass (CPB). This study investigated the effect of aprotinin on the post-operative levels of procalcitonin (PCT) and a set of cytokines in patients undergoing pulmonary artery endarterectomy (PEA). We analyzed 60 patients with chronic thromboembolic pulmonary hypertension undergoing PEA. 30 patients (Group A) were treated with aprotinin (2,00,00 IU prior anesthesia, then 2,00,00 IU in CPB prime and 50,00 IU per hour continuously); a further 30 patients (Group B) received tranexamic Acid (1 g before anesthesia, 1 g after full heparin dose and 2 g in CPB prime). PCT, TNFalpha, IL-1beta, IL-6, and IL-8 arterial concentrations were measured from before until 72 hours after surgery. Aprotinin significantly affected early post-PEA plasma PCT. Patients treated with aprotinin (Group A) had lower peak PCT levels compared to patients in Group B (1.52 ng/ml versus 2.18, p=0.024). Postoperative peak values of PCT and IL-6 correlated closely in both groups (r=0.78, r=0.83 respectively). Aprotinin attenuates the post-PEA increase of PCT in the same manner as other pro-inflammatory cytokines. Significant correlation between PCT and IL-6 post-surgery may be indicative of an indirect IL-6-mediated pathway of PCT alteration.

RISK FACTORS ASSOCIATED WITH PERIANESTHETIC MORTALITY OF STRANDED FREE-RANGING CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS) UNDERGOING REHABILITATION

The objective of this study was to identify risk factors associated with perianesthetic mortality of stranded free-ranging California sea lions (Zalophus californianus) undergoing rehabilitation. Hospital records of California sea lions that underwent heavy sedation or general anesthesia from 2004 through 2008 were reviewed, including records from 419 anesthetic events. Procedures that resulted in death during or in the subsequent 72 hr of anesthesia were classified as cases (n = 15). Procedures in which the animal survived were classified as controls (n = 334). Procedures that resulted in euthanasia (n = 70) were removed from subsequent analysis. The following risk factors were reviewed: gender, age class, health status, duration of anesthetic period, atropine premedication, induction protocols, maintenance protocols, and history of prior anesthesia. The prevalence of fatalities during anesthesia was 3.4% (n = 12) over the 5-yr period. With the inclusion of animals that died within 72 hr after anesthesia, the total mortality prevalence rose to 4.3% (n = 15). The most common time of death was during anesthetic maintenance. Health status was the single best predictor of anesthetic outcome, and sea lions premedicated with atropine had increased odds of anesthetic-related death.

Morphological variations caused by fixation techniques may lead to taxonomic confusion in Laeonereis (Polychaeta: Nereididae)

The nereidid polychaete Laeonereis acuta (Treadwell, 1923) is either considered to be a valid species, or a synonym of Laeonereis culveri (Webster, 1879). The species epithet, acuta, refers to the acuminate anterior region of the body followed by a widening that is visible up to the 10th setiger. The relative width of the anterior region of the body, however, has been reported in the taxonomic literature as variable for Laeonereis Hartman, 1945, a genus known from the eastern coast of North America to Patagonia (southern South America). To test whether variations in this character are real, or whether they correspond to an artifact, we analyzed morphological changes associated with different anesthesia and fixation techniques regularly used to prepare specimens of Laeonereis from southern Brazil (formerly reported as L. acuta). Six treatments, including combinations of anesthetics and fixative agents, and a control, were evaluated in groups of 25 adult animals. A simple model II regression analysis on living specimens showed that the growth is approximately isometric. One-way ANOVA was used to compare the treatment effect on the ratio of peristome width: setiger 6 width. This ratio was smaller in non-anesthetized individuals, especially when prepared in formalin and freshwater. When anesthetized with menthol and fixed in formalin with sea water, individuals retained a shape that was closest to their in vivo shape. Consequently, our results suggest that fixation without prior anesthesia is not recommended for morphological and taxonomical studies. Since morphology and morphometrics of the anterior region are consistently influenced by preparation techniques, it is likely that inadequate fixation routines have introduced several errors in the taxonomic and ecological literature of Laeonereis.

Isoflurane exacerbates electrically evoked seizures in amygdala-kindled rats during recovery

Neuroexcitatory effects of isoflurane during or following anesthesia are controversial, particularly in epileptic patients. In contrast, halothane is generally considered to be highly anticonvulsant. Kindling is an animal model of epilepsy suitable for studying the effects of anesthetic agents on the epileptic brain. Fully kindled, Sprague-Dawley rats were either untreated or received a 5 min exposure to isoflurane or halothane 30 min prior to a seizure and compared to seizures in the absence of prior anesthesia. Afterdischarge duration was assessed via electroencephalographs recorded from electrodes implanted in the basolateral amygdala and behavioral seizure stereotypy (stages I-V) was simultaneously recorded and analyzed using digital video for all seizures. Total seizure duration and clonus duration were significantly (P<0.05) increased 30 min after isoflurane but not halothane exposure relative to pre-treatment control. These results are the first to demonstrate that isoflurane exacerbates electrically evoked secondarily generalized seizures in fully kindled animals during recovery. These results also show that the kindling paradigm is useful for evaluating the mechanism of anesthetic agents that may be proconvulsant in epileptic subjects.

Treatment of Pachonychia congenita and Epidermolysis bullosa simplex with plantar injections of botulinum toxin

Pachonychia congenita (PC) and Epidermolysis bullosa simplex (EBS) are rare genodermatosis, which may be associated with painful, focal hyperkeratosis on the soles. Plantar sweating at high ambient temperatures increases the blistering of the callosities. Here we report 13 patients with PC (8) and EBS (5) who had great problems in walking, especially during summer time. They were treated with intracutaneous plantar injections of botulinum toxin type A (Dysport ® , Ipsen, Slough, UK, 100 U/ml) or type B (Neurobloc ® , Solstice Neurosciences Inc., 250 U/ml) after prior intravenous regional anaesthesia of the foot with a low tourniquet and 25 ml prilocaine (5 mg/ml) or general anesthesia. Within 1–2 weeks all 8 PC patients and 4 out of 5 EBS patients experienced dryness and a remarkable relief of pain from plantar pressure sites. The effect duration was 6 weeks to 12 months. Repeated injections over a period of 5 years confirmed the good results with no side effects or tachyphylaxis noted.

Świnka morska jako częsty obiekt eksperymentalnych badań otoneurologicznych

The aim of this research was to describe nomograms of brainstem auditory evoked potentials, oscillating stimulation of the vestibular organs and ultrastructural research methodology of a spiral organ of guinea-pigs. For the experimental purposes 60 guinea-pigs of both sexes, weight 250-300 grams, were used as research materials. After general anesthesia with Ketalar dosed 100 milligrams per kilogram and with Fentanyl dosed 0.1 milliliter per kilogram of the body mass, brainstem auditory evoked potentials were registered and the oscillating chair test (no prior anesthesia). Was placed on an assistant's knees, who was sitting on a chair. Then the guinea-pigs were anesthetized with 35 per cent solution of chloral hydrate intraperitoneally (dosed 1 milliliter per kilogram of the body mass). For electron microscopic research membranous helix was collected bilaterally by the method of micropreparation. Qualitative observation was conducted in the Philips' electron microscope (EM 300). On the basis of the obtained results it was concluded that the time of transmission between elements P1-P2 is constant and figures between 3.1 and 3.6 ms independently from a force of stimulation. Vestibular organs of a guinea-pig are more sensitive to high accelerations (17-12 degree/s2) than human vestibularl organs. However, their reaction is much weaker to lower accelerations (12-0 degree/s2). The processed nomograms of the brainstem auditory evoked potentials, oscillating stimulation of vestibular organs and methodology of ultrastructural research in guinea-pigs' spiral organs are expected to facilitate using them in experimental research.

Functional Magnetic Resonance Imaging in Conscious Animals: A New Tool in Behavioural Neuroscience Research

Functional magnetic resonance imaging (fMRI) is a unique window to the brain, enabling scientists to follow changes in brain activity in response to hormones, ageing, environment, drugs of abuse and other stimuli. There are two features that make fMRI unique when compared with other imaging modalities used in behavioural neuroscience. First, it can be entirely noninvasive: each animal can serve as its own control over the natural course of its life, vital for following neuroadaptation and other developmental processes critical to understanding behaviour. Second, fMRI has the spatial and temporal resolution to observe patterns of neuronal activity across the entire brain in less than a minute. Although fMRI does not have the cellular spatial resolution of immunostaining, nor the millisecond temporal resolution of electrophysiology, synchronised changes in neuronal activity across multiple brain areas seen with functional MRI can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviours. Thus, fMRI affords a systems approach to the study of the brain, complementing and building from other neurobiological techniques to understand how behaviour is organised across multiple brain regions. In this review, we present a general background to fMRI and the different imaging modalities that can be used in fMRI studies. Included are examples of the application of fMRI in behavioural neuroscience research, along with discussion of the advantages and disadvantages of this technology.

Endoskopische Untersuchungen der Eustachi-Röhre

Endoscopy of the eustachian tube allows direct examination of endoluminal alterations in the course of the organ. The aim of this study was to describe anatomic and functional findings in healthy awake subjects. Ten eustachian tubes in six healthy individuals with no history of tube dysfunction were examined under local anesthesia using different types of rigid and flexible endoscopes. Nine of ten tubes presented with no pathologic finding. The motility of the tube cartilage could be visualized in all cases and showed a wide variety. Prior anesthesia of the mucosa with the subject in the supine position, if necessary supplemented by a tube catheter, rendered the procedure more comfortable. The eustachian tube shows a wide spectrum of anatomic and functional varieties in normal subjects. The method allows comprehensive evaluation of anatomic and functional stenoses of the eustachian tube. The transnasal-transpharyngeal approach allows only limited evaluation of the middle ear structures.

CBF Changes Associated with Focal Ischemic Preconditioning in the Spontaneously Hypertensive Rat

Experimental stroke models exhibit robust protection after prior preconditioning (PC) insults. This study comprehensively examined cerebral blood flow (CBF) responses to permanent middle cerebral artery (MCA) occlusion in spontaneously hypertensive rats preconditioned by noninjurious transient focal ischemia, using [(14)C]iodoantipyrine autoradiography at varied occlusion intervals. Preconditioning was produced by 10-min occlusion of the MCA and ipsilateral common carotid artery under halothane anesthesia. These vessels were permanently coagulated 24 h later in naïve, PC, and sham-operated rats. Infarct volumes were determined from hematoxylin-eosin-stained frozen sections after 1 or 3 days. Edema-corrected infarct volume was reduced from 127+/-21 in naïve rats to 101+/-31 and 52+/-28 mm(3) in sham and PC groups, respectively, at 1 day, with similar results at 3 days. All animals exhibited a consistent CBF threshold for infarction (approximately 30 mL/100 g/min). Tissue volumes below this threshold were identical in naïve and PC groups after 15-min occlusion. However, by 3 h the volume of ischemic cortex decreased in the PC group but remained unchanged in naïve rats, predicting final infarct volumes. Cerebral blood flow recovery was confirmed in brains of individual rats evaluated by repeated laser Doppler perfusion imaging during the same 3-h interval. Modest sham protection correlated with better-maintained global perfusion, detectable also in the contralateral cortex, apparently reflecting the PC effects of prior anesthesia. These results establish that timely reperfusion of penumbra, achieved by synergistic mechanisms, is a primary determinant of PC-induced protection in experimental stroke.

Evaluation of slaughtering methods for turbot with respect to animal welfare and flesh quality

AbstractAfter elaborating a suitable scheme to assess consciousness/unconsciousness of turbot, the effects on fish welfare of commercial and experimental slaughtering techniques were evaluated. Strong adverse reactions and slow loss of clinical reflexes were observed when fish were slaughtered by bleeding without prior anaesthesia. The efficiency of electricity (150 V for 2 s followed by 25 V for 5 min) as a stunning and killing technique was dependent on the current frequency and mode of administration, ie whether the electrical discharge was applied to the head only or throughout the whole body. Finally, percussion of the head with a mechanical device resulted in immediate and permanent loss of all responses and reflexes in all fish tested. Three methods were selected as a result of the preliminary tests (bleeding in ice slurry, whole‐body electrical treatment and percussion), and their influence on flesh quality was studied over a 9 day period. Fish killed by percussion were characterised by a higher pH and higher water content in the very early stage of post mortem storage, but also by a much delayed rigor mortis. In contrast, fish killed by electricity entered most rapidly into rigor mortis; their flesh was significantly softer (p &lt; 0.05) throughout the entire storage time and was also redder and darker, as indicated by higher a* values (p &lt; 0.001) and lower L* values (p &lt; 0.01) respectively. It is suggested that automated percussion is a suitably humane method for the slaughter of farmed turbot.© 2002 Society of Chemical Industry