MAC Group Research Articles

How Good Is the Quality of Colonoscopy Preparation Under Monitored Anesthesia Care (Mac)?

Purpose: MAC is used in our hospital endoscopy unit for colonoscopy in high risk patients (pts) only. However, routine instructions about overnight fasting in pts undergoing colonoscopy under MAC by the anesthesiologists limits the use of AM dose of split dose regimen, which may interfere with the quality of colon preparation (prep). The aim of our study was to compare the quality of colon prep in pts undergoing colonoscopy under MAC & conscious sedation (CS) at our hospital endoscopy unit by grading the endoscopic photographs. Methods: Patients: Between 01/07 and 04/08, 163 pts underwent colonoscopy under MAC (study group); 57 pts used polyethylene glycol (PEG) based solution, 66 pts used Phosphosoda + Dulcolax (P), and 40 used other solutions. Two hundred pts undergoing colonoscopies under CS using PEG (N = 100) & P (N = 100) served as controls. Assessment: Grading of Cleansing For Each Colonic Segment was done by a single observer looking at the colonoscopy photos- Poor prep = stool obscured the mucosa; Fair prep = 50–100% of mucosa visualized along with few specks of stool; Excellent prep = 100% of the mucosa visualized without any stool. The Colon Cleansing Score for each colonoscopy exam was based on the overall quality of prep in different segments of the colon. Score 3: Excellent prep in all the segments of colon; Score 2: Fair prep in at least 1 segment; Score 1: Poor prep in at least 1 segment. Results: A. Poor Prep Rate: Higher in pts having colonoscopy under MAC as compared to those undergoing in CS (26% vs. 13.5%, P < 0.05). B. Colon Cleansing Score: Worse in pts having procedure under MAC compared to those undergoing in CS (2.15 ± 0.07 vs. 2.38 ± 0.05, P < 0.05) C. Effect of Prep Solution on Colon Prep Rate: Worse with PEG solution in the MAC group compraed to CS group (36% vs. 16%, P < 0.05), but no difference with Phosphosoda + Dulcolax (18% vs 11%, P= NS). ASA score: In the MAC group, the mean ASA score was 2.42 ± 0.06 and the CS group was 2.01 ± 0.03. (P < 0.05) Conclusion: Poor colon preparation is frequent in patients undergoing colonoscopy under MAC and especially worse with the use of PEG solution. Since these patients are sicker (higher ASA class), a split dose may benefit them (these under current investigation).Figure

Comparison of Early Results of Rotator Cuff Repair: Single Row MAC Configuration Versus Double Row Suture Bridge Technique (SS-27)

Double- row repair techniques in arthroscopic rotator cuff repair have been increasingly utilized by orthopaedists when treating rotator cuff tears. While this offers theoretical advantage over previous techniques such as single row fixation, the current study is aimed to compare results of the two methods of fixation. To compare single row with double row fixation in rotator cuff repair. Non-randomized assessment of 66 patients who had undergone arthroscopic rotator cuff repair with a single row simple over horizontal configuration (MAC) were compared to 26 patients who had the double row suture bridge configuration which effectively provided double row fixation and re-creation of the rotator cuff footprint. VAS, UCLA, and ASES scores were collected for both groups pre-operatively; then again at 3, 6, and 12 month intervals. In addition, dynometric strength assessment for subscapularis, supraspinatus, and infraspinatus was compared. No significant difference was shown between the two fixation methods preoperatively or at the 3 month follow-up visit. At the 6 month follow-up visit, the suture bridge configuration group showed poorer results for each of the VAS, UCLA, and ASES scores. At 12 months the UCLA and ASES scores were no different and the VAS score was slightly better for the MAC group. Strength in the MAC repair group at 12 months exceeded that for the suture bridge group for subscapularis, supraspinatus, and infraspinatus. Suture bridge configuration for rotator cuff repair is thought to provide a better repair by providing increased contact pressure of the repaired tendinous cuff to the native footprint while also increasing repair strength. Our current results suggest that a single row fixation method with a MAC configuration provides comparable results to double row repair outcomes as per strength assessment as well as VAS scores.

Allogeneic Stem Cell Transplantation in Angioimmunoblastic T-Cell Lymphoma (AITL): A Retrospective Survey from the Lymphoma Working Party (LWP) of the European Group for Blood and Marrow Transplantation (EBMT).

AITL is a rare peripheral T-cell lymphoma characterised by an aggressive behaviour, which primarily affects the elderly. Chemotherapy regimens fail to alter the high relapse rate and overall survival hardly exceeds 25% at 5 years. To date, there is no information on the potential role of allogeneic stem cell transplantation (allo-SCT) in the management of AITL. We report the outcome of 39 patients with a median age of 47 years (24–68), who underwent an allo-SCT between 1995 and 2004 for AITL, and were reported to the EBMT registry. The median time from diagnosis to transplant was 10 months (4–72). Thirty-four patients (87%) had previously received two or more treatment lines, and 16 patients (41%) a previous autologous SCT. Fifteen patients (38%) had a primary refractory disease, 13 (33%) were transplanted in partial remission and the remaining patients were in complete remission (CR) (mostly in 2nd and 3rd CR). Twenty-four patients were transplanted from an HLA-identical sibling and 15 from a matched unrelated donor. A myeloablative conditioning regimen (MAC) was used in 21 patients (cyclophosphamide + total body irradiation in 14), while 18 patients received fludarabine-based reduced intensity conditionings (RIC). Peripheral blood was the source of stem cells in 35 patients (90%). Three patients failed to engraft (one patient in the RIC group). Twenty-one patients (54%) developed acute graft versus host disease (grade I-II, n=16; grade III-IV, n=5). Twenty-eight patients (72%) achieved a CR after the allogeneic procedure. Nine patients died from transplant related mortality (TRM) and 5 patients from disease progression. The cumulative incidence of TRM at 12 months was 19% for the MAC and 26% for the RIC group. After a median follow-up for the surviving patients of 20 months (6–74), 25 patients are alive. Relapse rates at 1 and 3 years were estimated at 10% and 18% for the MAC and 16 and 20% for the RIC patients. Progression free survival rates at 3 years were 67% and 50% and the overall survival at the same time 71% and 56% for the MAC and RIC group of patients, respectively. Although follow up is rather short, these data suggest that allo-SCT results in good overall response and is associated with a low relapse rate in this group of poor risk heavily pre-treated and rather elderly group of AITL patients. Allo-SCT could be considered a therapeutic option for eligible high-risk AITL patients. Nevertheless, the impact of this approach should be further explored in prospective collaborative studies.

Comparing the glidescope (gl) with macintosh laryngoscope (mac) for intubating patients with a simulated difficult airway

The application of in-line stabilization (ILS) during endotracheal intubation of patients with suspected cervical spine injury makes visualization of the laryngeal inlet difficult1. We tested the hypothesis that the GL2 provides a better view of the larynx and results in a higher rate of successful intubation than the Mac. Materials and Methods Following institutional approval, written informed consent was obtained from ASA I and II patients requiring general endotracheal anesthesia. Exclusion criteria were: history of prior difficult intubation, morbid obesity (body mass index [BMI] > 35 kg/m2), gastroesophageal reflux disease and poor dentition. Patients were randomized into either GL or Mac. After onset of paralysis, ILS was applied. In GL patients, laryngoscopy was first performed with a Mac, then GL. The view obtained with either was scored3. If “good” (I or IIa), intubation was attempted with the GL. Otherwise, external laryngeal manipulation (ELM) was applied and if the view was “good”, the larynx was intubated. If not, the attempt was aborted and the intubation was considered “failed”. Patients in the Mac group had the same in the reverse order, with intubation attempted at Mac laryngoscopy. Time to intubation was recorded as the interval from when the blade passed the incisors to confirmation of tube placement by capnography. Means were compared using unpaired Student’s T-test and proportions, with Chi-test. P < 0.05 was considered significant. Results (See Table 1) Discussion GL provided a good view of the laryngeal inlet in 95% of attempts versus 44% with the Mac. The numbers improved to 100% and 60% with ELM. The success rate of intubation was higher with the GL (100% versus 65% with the Mac), but it took longer. Our preliminary data suggest that in comparison to Mac, GL is a better tool for laryngeal visualization and intubation in patients in whom ILS is applied. Reference List

202 Coronary artery wall thickness of the left anterior descending artery using high resolution transthoracic echocardiography an intra and inter operator variability

Results: 1 .Compared with the control group, the MAC group had a higher prevalence ,31 coronary artery disease (88.28% Vs 65.12%,P = 0.0003),and a higher prevalence el left main coronary disease(15.63% Vs 4.65%,P = 0.007)and triple vessel disease(55.47% Vs 32.56%,P = 0.001).2.On multivariate analysis, MAC(P=0.008)was the independent predictors el coronary artery disease, and the predicting value el MAC were higher than hyperlipidaemia(P=0.02), chesl pain(P=0.0G)and age (P=0.04). 3. The positive predictive value el MAC lot find- ing coronary arlery disease was 88.28%. Conclusions: In patients aged=65years, There is a significant association be- tween the presence el MAC and coronary artery disease. MAC may be an im- portant marker for coronary artery disease. Coronary arteriongraphy should be underwent to the patients with MAC diagnosed by translhoracic echocardiography as a common. Of the risk laclors studied, hyperlension(P<0.05)and diabetes mellilus(P<0.001)were significantly associ- ated with MAC. Hyperlension(P<0.01),diabetes mellitus(P<0.05)and a smok- ing hislory(P<0.05)were significantly more prevalent in patients with AVC than those wilhoul AVC. Hyperlension was significantly more frequent in palienls wilh AVAC(P<0.05).2. There was a progressive increase in age(P<0.001), prevalence of hypertension(P<0.00t)and diabetes(P<0.05) with an increasing number el silos with calcium deposits. 3. Compared with patients with no calcium deposits, those with calcium deposils had a significantly higher positive prevalence el coro- nary arteriongraphy(P<0.0t), and lhere was a progressive increase in positive prevalence el coronary arteriongraphy(P< 0.001).4. Multiple logistic analyses iden- tified the multiple calcium deposits(P<0.01 ), age(P<0.05), male gender(P<0.001 ), diabetes mellitus(P<0.001 ), and hypercholesterolemia(P<0.05)as significant pre- dictors lor the positive prevalence el coronary arteriongraphy. )he multiple calcium deposils(P<0.001)and diabetes mellilus(P<0.001)were significant pre- dictors in lemale patients. In patients aged =55 years, the multiple calcium deposits(P<0.05), diabetes mellitus(P<0.05), smoking history(P<0.05)and male gender(P<0.05)were stalislically significant predictors el the posilive prevalence of coronary arteriongraphy. Conclusions: There is a significanl association between the presence el calcium deposits and coronary artery disease. The presence el multiple calcium deposits is an independent predictor el coronary arlery disease. these measurements. Thirty volunteers with- out a hislory el cardiac disease underwent a HRTTE assessment el their LAD by two dillerenl operators on three separate occasions. Resulls: The correlations lor inlra-operator variability were r= 0.86 (p<0.001), r=0.86 (p<0.001), r=0.81 (p<0.001) and r=0.85 (p<0.001) lot anterior and pos- terior wall thickness and luminal and e~ternal diameters respectively. The correla- lions lot inter-operator variability were r=0.68 (p<0.001), r=0.82. (p<0.001), r=0.76 (p<0.001) and r=0.70 (p<0.001) for anterior and posterior wall thickness and lumi- nal and external diameters respectively. Conclusion: HRTTE measurement el the LAD vessel is reproducible within and between operators in normal volunteers. This technique lherelore warrants lurlher sludy as a potential screening medalily lot subclinical coronary atherosclerosis.

Haemodynamic effects of haemorrhage during xenon anaesthesia in pigs

It was hypothesized that xenon would stabilize mean arterial pressure (MAP) in haemorrhagic shock, recovery, and volume resuscitation, because a higher MAP has been observed with xenon, when compared with isoflurane anaesthesia. The responses to haemorrhage and subsequent volume replacement were therefore compared between xenon and isoflurane anaesthesia, in pigs. Pigs were randomized to anaesthesia with xenon 0.55 MAC (group Xe, n=9) or isoflurane 0.55 MAC (group Iso, n=9), each with remifentanil 0.5 microg kg(-1) min(-1). MAP, heart rate, cardiac output (CO), and left ventricular fractional area change (FAC) were collected at control (1), after haemorrhage (20 ml kg(-1)) (2), after 10 min of recovery (3), after volume replacement (4), and 30 min later (5). Data were analysed by two-way repeated measures anova. Blood loss decreased MAP (Xe: 103 [21] to 53 [24] mm Hg; Iso: 92 [18] to 55 [14] mm Hg) and CO (Xe: 4.1 [0.8] to 2.6 [0.5] litre min(-1); Iso: 5.1 [1.1] to 3.8 [1.2] litre min(-1)), in spite of significant tachycardia. MAP and CO recovered to about 75% of control, and subsequent volume replacement completely reversed symptoms in both groups, but increased FAC only with xenon. Haemodynamic response to acute haemorrhage appeared faster with xenon/remifentanil than with isoflurane/remifentanil anaesthesia. In particular MAP decrease and short-term recovery were more marked with xenon (P<0.02). In the xenon group, volume replacement increased FAC compared with control and isoflurane (P<0.02).

The Effect of Enflurane on the Tracheal Smooth Muscle Contracted with Electrical Field Stimulation in the Guinea Pig

Background: Inhalation anesthetics have been known as bronchodilators, and there are reports that enflurane has some relaxing effects on tracheal smooth muscles. However, there are not so many reports on the ACh release in the postganglion nerve endings. We tried to evaluate the effect of enflurane on the contraction of the tracheal smooth muscle in the postganglion nerve ending in guinea pigs. Methods: Isolated tracheal preparations of guinea pigs were used and contractions were induced by electrical field stimulation (3 Hz & 30 Hz). In the pilocarpine- enflurane group, pilocarpine ( M) was administrated and enflurane (1 MAC and 2 MAC) was administered. In the gallamine-enflurane group, gallamine ( M) was administrated and enflurane (1 MAC and 2 MAC) was administered. In the enflurane 1 MAC group and 2 MAC group, contractions were induced by electrical field stimulation before and after administration of enflurane. The percentile contraction to the contraction induced by acetylcholine ( M) were evaluated. Results: The potentiation of the contraction which was induced by electrical field stimulation was observed by enflurane administration and with prior administration of pilocarpine ( M), with prior administration of gallamine ( M). There was no potentiation of contractions, but potentiation of the contraction was observed with enflurazne (2 MAC, 30 Hz). Conclusions: Enflurane potentiates the contraction induced by electrical field stimulation in guinea pig tracheal smooth muscle. These findings seem to be related with prejunctional M2 receptor in the postganglionic nerve endings.

Nino Migliori

When Nino Migliori (born in Bologna 1926, where he still lives and works) began his career in photography, ideas about visual art in Italy were divided into two main camps. From the end of the Second World War up to 1948, when Migliori's first photographs were produced, a bitter debate continued between those who championed the mirroring function of art and those who were more interested in the exploration of expression, which was made possible by the avant-garde movements. This ideological battle, which pitted groups of artists such as II Fronte Nuovo delle Arti against the II Milione group, the MAC group, and the Corrente group among others,1 was very complex, and involved themes ranging from ideological commitment to purely aesthetic questions. However, we can not reduce these arguments to the mere opposition between realism and abstraction, or between political commitment and fomulism. Nevertheless, the artists themselves were placed in these categories, and the divisions between them have characterized the evaluation of photographic, literary, and film production as well as painting since that time. Immediately after the war, photography in Italy was also burdened by a cultural environment that was deeply influenced by Benedetto Croce's idealism, which maintained that a sharp Jivisiun existed between ‘poetry’ and ‘non-poetry’.2

Pharmakodynamische Effekte des Phosphodiesterasehemmers Enoximon unter dem Einfluß der volatilen Anästhetika Halothan und Isofluran beim koronarchirurgischen Patienten

We investigated the pharmacodynamic effects of the phosphodiesterae inhibitor enoximone in the presence of halothane and isoflurane in 20 patients, ASA class III, aged 45-75 years, undergoing coronary artery bypass grafting. The study was approved by the local Medical Ethics Committee and patients' informed written consent was obtained. After induction of anaesthesia (midazolam, fentanyl, etomidate and pancuronium) all patients received either halothane 1 MAC (group I, n = 10) or isoflurane 1 MAC (group II, n = 10), followed 20 min later by enoximone 0.5 mg/kg. Haemodynamic variables were measured and blood samples (arterial, mixed venous) were obtained before the administration of the volatile anaesthetics (control, t0), immediately (t1) and 5 (t2) min after steady state conditions with halothane or isoflurane, as verified by the end-expiratory concentration and 5 (t3) and 10 (t4) min after the injection of enoximone. Heart rate (HR), mean arterial pressure (MAP), mean pulmonary artery pressure, pulmonary capillary wedge pressure and right atrial pressure were recorded. Cardiac (CI) and stroke volume indices, systemic (SVR) and pulmonary vascular resistance, oxygen availability (AO2) oxygen consumption and oxygen extraction rate were calculated using standard formulae. In both groups HR remained essentially unchanged throughout the investigation period. MAP decreased significantly in both groups under steady state conditions with the volatile anaesthetics (group I: 19%; group II: 30%) but remained unchanged after subsequent injection of enoximone. After administration of halothane SVR remained essentially unchanged, whereas isoflurane decreased SVR significantly by 20%. After enoximone, there was a significant decrease in SVR in both groups (group I: 26%; group II: 25% compared with the values obtained after halothane and isoflurane respectively). Halothane and isoflurane decreased CI significantly and to a similar degree (group I: 17%; group II: 17%). After the injection of enoximone CI increased significantly and reached control values in both groups. AO2 decreased significantly after administration of the volatile anaesthetics (group I: 19%; group II: 21%) and increased significantly after administration of enoximone, returning to control values. Halothane (7%) and isoflurane (13%) produced a significant increase in oxygen extraction. After bolus injection of enoximone oxygen extraction decreased significantly and returned to control value in group II. In group I enoximone decreased oxygen extraction significantly compared with control. Our results suggest that in the presence of halothane or isoflurane the phosphodiesterase inhibitor enoximone produces a comparable increase in cardiac output and decrease in systemic vascular resistance in patients with coronary artery disease.

HAEMODYNAMIC CHANGES PRODUCED BY INHALATION ANAESTHETICS IN THE PHOSPHODIESTERASE INHIBITION

We have investigated the circulatory effects of halothane and isoflurane in the presence of the phosphodiesterase inhibitor, enoximone, in 20 patients, ASA class III, aged 40-70 yr, undergoing coronary artery bypass grafting. After induction of anaesthesia (midazolam, fentanyl, etomidate and pancuronium) all patients received enoximone 0.5 mg kg-1, followed, 10 min later, by either halothane 1 MAC (group I; n = 10) or isoflurane 1 MAC (group II; n = 10). Haemodynamic variables were measured and blood samples (arterial and mixed venous) were obtained before (control, t0), 5 (t1) and 10 (t2) min after the injection of enoximone and immediately (t3) and 5 (t4) min after steady state conditions with halothane or isoflurane, as verified by the end-expiratory concentration. Heart rate, mean arterial pressure (MAP), mean pulmonary artery pressure, pulmonary capillary wedge pressure and right atrial pressure were recorded. Cardiac (CI) and stroke volume indices, systemic (SVR) and pulmonary vascular resistance, oxygen availability (QO2), oxygen consumption and oxygen extraction rate were calculated using standard formulae. MAP decreased significantly in both groups after bolus injection of enoximone (group I: 11%; group II: 7%). Under steady state conditions with the volatile anaesthetics, a further significant decrease in MAP was observed (group I: 12%; group II: 12%). Enoximone produced a significant increase in CI (group I: 25%; group II: 27% compared with control). After administration of isoflurane, CI remained essentially unchanged, while halothane decreased CI significantly by 20%. In both groups, SVR decreased significantly after administration of enoximone (group I: 26%; group II: 24%).(ABSTRACT TRUNCATED AT 250 WORDS)

Enflurane suppresses phrenic nerve-diaphragm transmission in vivo.

We examined the effects of enflurane on the diaphragmatic function in 15 pentobarbital-anesthetized, mechanically ventilated dogs. They were divided into three groups of five animals each, according to the administered concentration of enflurane. The diaphragmatic function was assessed from transdiaphragmatic pressure (Pdi) and integrated diaphragmatic electromyography (Edi) developed at functional residual capacity against an occluded airway during bilateral supramaximal phrenic nerve stimulation at 0.5, 10, 20, 50 and 100 Hz under quasiisometric condition. After a control measurement, enflurane was administered at a constant end-expired concentration (0, 0.5 and 1 MAC) and the measurement was repeated after 1 hour of exposure. The Pdi amplitude generated by single twitch (0.5 Hz) and during 10, 20 and 50 Hz stimulation was unchanged between the groups. No change in Pdi during 100 Hz stimulation was noted during 0 and 0.5 MAC exposure, while it was reduced by 1 MAC of enflurane. When the values of Pdi were expressed as % of maximum Pdi (%Pdi,max) that developed during control measurement and analyzed in terms of %Pdi,max-stimulus frequency relationship, a significant decrease in %Pdi,max was noted for 100 Hz stimulation in 0.5 and 1 MAC groups compared to the control. Similarly, Edi during 100 Hz stimulation obtained in 0.5 and 1 MAC groups was markedly depressed compared to the control. Edi during 50 Hz stimulation was also decreased at 1 MAC. Relative changes in Edi following enflurane administration were greater than the corresponding changes of Pdi. These results demonstrate that enflurane impairs diaphragmatic function through its inhibitory effects on neuromuscular transmission.

Desflurane and Isoflurane in Surgical Patients

In order to examine the clinical potential of desflurane (difluoromethyl-1-fluoro-2,2,2-trifluoroethyl ether) in humans, a randomized, controlled study was designed to compare time of emergence from anesthesia in patients undergoing elective surgery under desflurane anesthesia to that of patients under isoflurane anesthesia. Twenty-eight patients were randomly divided into four groups. Group 1 received isoflurane 0.65 MAC; group 2, desflurane 0.65 MAC; group 3, isoflurane 1.25 MAC; and group 4, desflurane 1.25 MAC. Anesthesia was induced with sodium thiopental, and N2O 60% was added to the volatile agent. Mean anesthetic exposure times (min [mean +/- SD]) were 108 +/- 49 in group 1, 132 +/- 46 in group 2, 147 +/- 74 in group 3, and 166 +/- 71 in group 4, with no significant differences between groups. The times from discontinuation of anesthetic gases until patients opened their eyes and squeezed the investigator's hand in response to a command were averaged and recorded as "emergence time." Emergence time was significantly less with desflurane than with isoflurane given at the same MAC. Patients receiving isoflurane 0.65 MAC responded to commands 15.6 +/- 4.3 min after discontinuation of the anesthetic; patients in the desflurane 0.65 MAC group responded in 8.8 +/- 2.7 min (P less than 0.01). Emergence time for isoflurane 1.25 MAC was 30.0 +/- 11.0 min; for desflurane 1.25 MAC it was 16.1 +/- 6.0 min (P less than 0.05). Our results confirm that emergence from desflurane anesthesia is more rapid than from isoflurane.

EFFECTS OF ENFLURANE AND ISOFLURANE IN AIR-OXYGEN ON CHANGES IN THERMAL BALANCE DURING AND AFTER SURGERY

The temperatures in the aural canal (core), skeletal muscle and skin surface were measured during anaesthesia and surgery in 32 healthy females undergoing total abdominal hysterectomy and for 4 h after operation. The patients were allocated randomly to one of four groups according to the end-tidal concentration of volatile anaesthetic: 1 MAC isoflurane, 1 MAC enflurane, 1.8 MAC isoflurane and 1.8 MAC enflurane. The lungs were ventilated with an air-oxygen mixture. Neuromuscular block was produced with pancuronium. Room temperature and i.v. fluid administration were standardized. Aural canal, muscle and mean skin temperatures decreased significantly in all groups during surgery (P less than 0.001). The decrease in core and muscle temperatures, and mean body heat was significantly greater in the 1.8 MAC groups than in the 1 MAC groups for both volatile agents (P less than 0.001). However, there was a significantly greater decrease in core temperature and mean body heat in the isoflurane compared with the enflurane group (P less than 0.026). Body temperature returned to preoperative values during the recovery period. There was a significantly greater rate of rewarming during the first 1 h of recovery in the 1.8 MAC groups compared with the 1 MAC equivalent (P less than 0.001), and this was independent of the volatile agent used. The present results are compared with those reported previously in which nitrous oxide was added to the volatile agents. The decrease in body temperature depends upon the concentration of vapour used. However, it appears that isoflurane, without nitrous oxide, caused greater loss of body heat than enflurane.

Effect of Isoflurane Anesthesia on Local Cerebral Glucose Utilization and Local Cerebral Blood Flow in Rats

The influence of isoflurane on local cerebral glucose utilization and local cerebral blood fiow was studied by quantitative autoradiography using 23 male Sprague-Dawley rats. rats had both the femoral artery and vein cannulated and were anesthetized with 0.5 MAC and 1.0 MAC isoflurane. Local cerebral glucose utilization and local cerebral blood flow were compared between conscious controls and isofiurane anesthetized rats. The results were as follows: 1) There was a slight decrease of blood pressure in the anesthetized group but it was within the range of autoregulation. The PaO₂ and PaCO₂ were influenced by artificial ventilation in the anesthetized group but were in the normal range. 2) 1-CM-Rg was decreased in most regions and there was no significant difference between the 0.5 MAC and 1.0 MAC isoflurane anesthesia groups. 3) Some regions had increased glucose utilization. They were the cerebellum nucleus, vestibular nucleus, substantia nigra pars compacta, and hippocampus molecular layer. 4) Some regions had prominent glucose utilization in the anesthetized rats which did not appear in coscious controls. They were the havenula, havenulo-interpedunculus nucleus and fornix. 5) The order of decreased glucose utilization was cerebral association area>auditory system> visual system > sensory motor system > limbic system > extrapyramidal system = myelinated fiber. This means most of the cerebral cortex and auditory system had decreased glucose utilization but extrapyramidal system was well preserved by isoflurane anesthesia. 6) The order of decreased glucose utilization according to anatomical region was telencephalone> diencephalone > mesencephalone > metencephalone > mylencephalone, which means there is rostraI to caudal gradient of glucose utilization. In other words, forebrain was more affected than the hindbrain, so unconsciousness can be achieved with isoflurane with no specific effect on respiration, blood pressure or temperature. 7) Local cerebral blood flow was significantly increased in anesthetized group, and was especiaBy more increased in 0.5 MAC anesthetized group, but some regions (cerebellum white, thalamus) showed decreased blood flow. 8) The order of increased cerebral blood flow was visual system > sensory motor system > auditory system= limbic system > extrapyramidal system) myelinated fiber> cerebral association area in the 0.5 MAC group; but in the 1.0 MAC group, it was visual system>limbic system>extrapyramidal system>sensorymotor system auditory system>myelinated fiber>cerebral association are. 9) The order of increased cerebral blood flow according to the anatomical region was mesencephalon>myelencephalon>diencephalon>telencephalon Metencephalone in 0.5 the MAC group but in the 1.0 MAC group, it was myelencephalon>mesencephalon>diencephalon>telencephalon>metencephalon. 10) There was flow-metabolism uncoupling, although much less than with other inhalation anesthetics, with low metaholism and high blood flow by isoflurane anesthesia. The ratio (1-CBF/ 1-CMRg) was four times greater than control group in the 0.5 MAC group, and three times greater in the 1.0 MAC. 11) Some nucleus of limbic system were prominent in glucose utilization with no significant eidence of limbic seizure but may have some degree of protective effect in the hypoxic or ischemic brain.

Rb–Sr ages of silicic igneous rocks and deformation, Burlington Peninsula, Newfoundland

The Burlington Peninsula, east of the Baie Verte Lineament, is underlain by the Eastern Division of the Fleur de Lys Supergroup, a sequence of metasediments and metavolcanic rocks that is intruded by plutonic masses of granitic to granodioritic composition. This sequence has been designated as Cambrian or older and the deformation and metamorphism in the area interpreted as pre-Ordovician. Recently, however, it has been shown that at least part of the succession is post Lower Ordovician and a mid or late Palaeozoic age has been proposed for the major deformation affecting the area.Rb–Sr ages obtained in the present study area are: (a) whole-rock isochrons—Dunamagon Granite, 413 ± 10 Ma; Cape Brulé Porphyry, 393 ± 25 Ma; Cape St. John Group Ignimbrites, 343 ± 15 Ma and 429 ± 50 Ma; Mic Mac Group Ignimbrite, 375 ± 15 Ma; (b) Biotite ages—Dunamagon Granite, 334, 356 and 358 Ma; (c) Mineral isochron—Burlington Granodiorite, 422 ± 40 Ma. Because of extensive trace element migration in at least some of these units, the interpretation of the ages is complex and does not allow a unique history of the area to be determined. However, the ages do support the proposed mid or late Palaeozoic age for the major deformation and indicate that pre-Ordovician orogeny did not prevail on the scale previously envisaged.

Post-Ophiolite Unconformity, Tilt Cove – Betts Cove Area, Newfoundland

Subaerial sediments and silicic and mafic lavas of the Cape St. John Group in northern Newfoundland, were originally interpreted as younger than the Betts Cove ophiolite suite and the Lower Ordovician (Arenig) Snooks Arm pillow lavas and oceanic sediments, but recently have been considered as part of the pre-Ordovician Fleur de Lys Supergroup and hence older than the Snooks Arm Group. The volcanic rocks that underlie the Cape St. John were reinterpreted as a pre-Snooks Arm oceanic foundation to the Fleur de Lys rocks.Our work reaffirms the original interpretation of the Cape St. John rocks as unconformably above the Lower Ordovician pillow lavas and ophiolites and we tentatively correlate them with the Springdale and Mic Mac Groups and other nearby Silurian (?) clastic/volcanic sequences of Old Red Sandstone equivalence. The Cape St. John Group grades northward and westward into polydeformed rocks, hence its re-establishment as a post-ophiolite assemblage bears on the history of deformation of adjacent groups.

New York area MAC group formed

New York area MAC group formed

New MAC groups approved by Council

New MAC groups approved by Council

Cholesterol turnover, synthesis, and retention in hypercholesterolemic growing swine

Studies of the interaction of cholesterol absorption, excretion, synthesis, and retention were carried out with growing swine through the application of sterol and isotopic balance procedures to a non-steady state situation. The animals were fed either a low-fat commercial mash diet (MA), a commercial mash diet plus 2.4 g/day of crystalline cholesterol (MAC), or a high-fat milk diet containing 2.4 g/day cholesterol (MKC). [(14)C]Cholesterol and beta-[(3)H]sitosterol were used to measure fecal neutral steroid losses. Final plasma cholesterol levels averaged 91, 85, and 195 mg/100 ml for MA, MAC, and MKC animals, respectively. Total carcass dissection followed by cholesterol measurement revealed that accumulation of cholesterol in most body tissues was directly related to increase in body size in the rapidly growing swine. The only notable exceptions were plasma, liver, and bone with marrow of the MKC group, where cholesterol concentrations were significantly elevated. Absorption of cholesterol was significantly greater in animals fed MKC than MAC-fed swine (726 mg/day vs. 142 mg/day), whereas synthesis of cholesterol was significantly greater in MAC animals than in MKC animals (863 mg/day vs. 112 mg/day). Excretion of neutral and acid steroids into the intestine was not significantly different between MAC and MKC groups, but both classes of steroids were more efficiently reabsorbed in MKC animals. The overall differences between swine fed mash-cholesterol and those fed milk-cholesterol diets appear to result from more efficient absorption of both neutral and acid steroids in the milk-cholesterol group only partially compensated for by decreased cholesterol synthesis.