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PubMed1999

Pancreas ultrastructural alterations in mice inoculated with Tityus discrepans (Buthidae) venom.

The symptoms of scorpionic envenomation in mice appear almost immediately after intraperitoneal injection and are manifested by great agitation, hair bristling, accelerated respiration, salivation and lacrimation, vomits and diarrhoea. In this work we intend to correlate those clinical manifestations appearing in response to the toxic aggression by Tityus discrepans venom, to the cellular or subcellular alterations produced in the mouse pancreas, probably similar to those damages found in envenomed humans. To evaluate pancreas subcellular response to Tityus discrepans venom, male C57/Bl adult mice were randomised into two groups: envenomed were intraperitoneally injected (hypochondrial left region) at a dose of 5 mg/Kg weight and controls received saline solution. Samples after preparation were studied in a Hitachi-300 transmission electron microscope. The most relevant ultrastructural changes in pancreatic tissues were an increase in the nuclear heterochromatin, with a corresponding decrease of euchromatin. In the cytoplasm, rough endoplasmic reticulum exhibited zones of oedema, losing its organised aspect. The secretion granules presented smaller electron density and variability in dimensions. At higher magnification a nucleus with picnotic appearance, with indentation of its perinuclear cistern was observed. There was a mitochondrial degeneration, with destruction of the mitochondrial matrix and autophagic vacuoles in its interior. At 48 h the lesions became intensified, with an evident increase in the intercellular spaces.

Animals↗

PubMed2006

[Minimally invasive surgery of the pituitary and the sellar region].

INTRODUCTION: New minimal invasive neurosurgical approaches for the treatment of diseases in the sellar and perisellar regions (superciliary and paraseptal approach, perioperative ACTH measurements, application of endoscopes and neuronavigation) were introduced by the author. The modified surgical techniques were applied by the author successfully in the treatment of more than 1000 cases, of which the data of 746 patients were analysed and the results are presented. METHODS AND RESULTS: The results of the clinical studies concerning superciliary and paraseptal approaches were as follows: length of the operations and, loss of blood were decreased, the patients needed shorter anesthesia and the treatment cost became lower. The approaches were performed without hair cutting with excellent cosmetic results leading to easier resocialisation of the patients. In the group of the patients operated on through the superciliary approach postoperative vasospasm developed in significantly lower rate, the number of days spent in the intensive care unit decreased and the rate of patients on discharge in good clinical condition were higher. The study on perioperative plasma ACTH simultaneous measurements with rapid and standard methods revealed first in the literature that, during anaesthesia in patients with ACTH producing adenoma the plasma ACTH level changed individually. There was no difference between arterial and venous plasma ACTH concentration in the same patient and the ACTH concentration in the bleedings from the peripituitary bony structures are individually variable, representing the network of the venous outflow of the pituitary. The decrease in the plasma ACTH concentrations in the peripheral venous samples two hours after operation and next morning proved the radical removal of the adenoma. The differences between concentrations in the left and right sides indicate the intrapituitary lateralization of the adenoma. The study on the usefulness of neuroendoscopy and neuronavigation in the author's hand revealed the advantages and disadvantages of these new neurosurgical instruments. CONCLUSIONS: With the advent of the minimal invasive methods in surgery of the pituitary and the sellar region the mortality end the morbidity of the operations decreased.

Adenoma↗

PubMed1980

Computerized quantitation of regional myocardial perfusion in man.

A computerized procedure has been developed for the generation, graphic presentation and quantitative evaluation of circumferential profiles of thallium-201 myocardial perfusion. The computer data are first filtered using a two-dimensional fast Fourier transform. The optimum criteria for evaluating the profiles of the left anterior oblique (LAO) view have been empirically determined for both rest and stress. The sensitivity of 89 percent and specificity of 75 percent compare well with the results of other methods and are free of the variables of visual interpretation.

Coronary Circulation↗

PubMed2002

Relationship between interleukin-6 production in the lungs and pulmonary vascular resistance in patients with congestive heart failure.

STUDY OBJECTIVES: We evaluated whether interleukin (IL)-6 is produced in the pulmonary circulation and investigated the relationship between IL-6 spillover in the lung and pulmonary vascular resistance (PVR) in patients with congestive heart failure (CHF). PATIENTS AND INTERVENTIONS: Blood samples were obtained from the main pulmonary artery and pulmonary capillary wedge region in 50 patients with symptomatic left ventricular dysfunction, who had undergone cardiac catheterization, and 9 age-matched control subjects. Plasma IL-6, tumor necrosis factor-alpha, norepinephrine (NE), endothelin-1, atrial and brain natriuretic peptide, and cyclic guanosine monophosphate (cGMP) levels were determined. MEASUREMENTS AND RESULTS: Plasma IL-6 concentrations were significantly higher in the pulmonary capillary wedge region than in the main pulmonary artery in both control subjects and patients with CHF. IL-6 production in the lung increased markedly in patients with severe CHF compared with control subjects and patients with mild CHF. Among hemodynamic variables, neurohumoral factors, and medications, plasma NE levels (p < 0.0001) showed an independent and significant positive relationship with IL-6 production in the lung, and treatment with beta-blockers (p = 0.004) showed an independent and significant negative relationship with IL-6 production in the lung. There was a significant positive correlation between IL-6 production in the lung and both PVR (r = 0.43; p = 0.001) and cGMP production in the lung (r = 0.498; p < 0.0001). CONCLUSION: IL-6 production in the pulmonary circulation increases with the severity of CHF and is mainly associated with the activation of the sympathetic nervous system. The local production of IL-6 in the lung may modify PVR in patients with CHF.

Adult↗

PubMed1987

Impaired left ventricular filling dynamics during percutaneous transluminal angioplasty for coronary artery disease.

The effects of brief periods of major coronary artery occlusion on global and regional peak left ventricular (LV) filling rates were studied during angioplasty in 10 patients. No patient had had a previous myocardial infarction. High-fidelity LV pressure and volume were determined by angiography before and 20 and 50 seconds after the onset of transluminal coronary occlusion and soon after the last balloon inflation. Segmental wall motion was analyzed frame by frame along 20 hemiaxes. Global peak filling rate decreased significantly both after 20 (29%, p less than 0.05) and 50 seconds (27%, p less than 0.05) from the onset of the occlusion. The term sigma delta t1 was defined as the sum of the absolute values of the time differences from the occurrence of global peak filling rate and the segmental peak filling rate in 20 segments. This variable increased significantly during both periods of transluminal occlusion (by 73% and by 72% [both p less than 0.005], respectively), indicating asynchrony in the occurrence of regional peak filling rate. Simultaneously, the sum of intervals between aortic valve closure (end systole) and occurrence of peak segmental shortening, sigma delta t2, measured in the 20 segments, increased by 63% after 20 seconds and by 87% after 50 seconds (both p less than 0.005), showing major asynchrony in segmental contraction. A significant negative correlation was found between global peak filling rate and both sigma delta t1 and sigma delta t2 (r = 0.64, p less than 0.001 and r = 0.70, p less than 0.0001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗

PubMed2005

Single-ventricle physiology reduces cerebral oxygen delivery in a piglet model.

BACKGROUND: In single-ventricle physiology, cerebral blood flow and oxygen (O2) delivery may be inadequate. This study tests the hypotheses that in acute univentricular physiology (1) cerebral blood flow increases inadequately to maintain O2 delivery, (2) the brain is incapable of increasing O2 extraction due to hypoxemia, and (3) cerebral O2 delivery diminishes selectively in different brain regions. MATERIAL AND METHODS: Univentricular physiology was created in 8 piglets, while 8 animals were sham controls. Aortopulmonary shunt, echocardiography-guided atrial septostomy, tricuspid valve avulsion, and pulmonary artery occlusion were performed to allow the left ventricle to support systemic and pulmonary circulations. Cerebral blood flow (microspheres), cerebral O2 and lactate metabolism, and cerebral O2 saturation were measured at baseline, 30 minutes, and 120 minutes after conversion to univentricular physiology. RESULTS: Cerebral blood flow increased in the cerebrum and subtentorium in controls (p < 0.05), whereas it remained unchanged in univentricular piglets. Cerebral O2 delivery at 30 and 120 minutes was lower in univentricular physiology than in controls (p = 0.05). Fractional oxygen extraction was unchanged in both groups. Cerebral O2 consumption trended lower in univentricular physiology (p = not significant), while it was unchanged in controls. Lactate cerebral metabolic rate (CMRLactate) increased at 30 and 120 minutes in both groups. The decline in O2 delivery was variable, but present in nearly all brain regions. CONCLUSIONS: This study confirms the hypothesis that, in univentricular physiology, hypoxemia and limited cerebral blood flow reduce cerebral O2 availability in nearly all regions. These findings contribute to the understanding of brain abnormalities in infants with univentricular physiology.

Animals↗

PubMed1990

Cardioprotective effects of amlodipine on ischemia and reperfusion in two experimental models.

The cardioprotective effect of amlodipine, a long-acting dihydropyridine derivative, was studied in 2 experimental models of ischemia and reperfusion. Isolated and blood-perfused feline hearts were made globally ischemic for 60 minutes and then reperfused for 60 minutes. Alterations of left ventricular developed pressure and compliance were monitored in both amlodipine-treated hearts and saline-treated control animals. Changes in perfusion pressure indicated that amlodipine significantly reduced myocardial oxygen consumption and coronary vascular resistance. Furthermore, a progressive increase in resting left ventricular diastolic pressure indicated that amlodipine, administered before the onset of global ischemia, attenuated the development of ischemic contracture. Return of contractile function 60 minutes after reperfusion and maintenance of tissue concentrations of electrolytes were significantly better in the amlodipine-treated group than in the control animals. In intact canine hearts, regional myocardial ischemia was induced for 90 minutes, followed by 6 hours of reperfusion. Although the hemodynamic variables and the size of the region of risk did not differ significantly between treated animals and control animals, the infarct size was significantly smaller in the amlodipine-treated group than in the control animals, and a gradual reduction in coronary blood flow was observed in the control group that was prevented in the amlodipine group. A comparison of these findings with those observed with oxygen radical scavengers also is discussed. A detailed report of these studies was published in The American Journal of Cardiology (1989;64:101I-116I). This review is included here to maintain continuity of the symposium for the convenience of the reader.

Amlodipine↗

PubMed1996

Origin and evolution of homologous repeated sequences in the mitochondrial DNA control region of shrews.

The complete mitochondrial DNA (mtDNA) control region was amplified and directly sequenced in two species of shrew, Crocidura russula and Sorex araneus (Insectivora, Mammalia). The general organization is similar to that found in other mammals: a central conserved region surrounded by two more variable domains. However, we have found in shrews the simultaneous presence of arrays of tandem repeats in potential locations where repeats tend to occur separately in other mammalian species. These locations correspond to regions which are associated with a possible interruption of the replication processes, either at the end of the three-stranded D-loop structure or toward the end of the heavy-strand replication. In the left domain the repeated sequences (R1 repeats) are 78 bp long, whereas in the right domain the repeats are 12 bp long in C. russula and 14 bp long in S. araneus (R2 repeats). Variation in the copy number of these repeated sequences results in mtDNA control region length differences. Southern blot analysis indicates that level of heteroplasmy (more than one mtDNA form within an individual) differs between species. A comparative study of the R2 repeats in 12 additional species representing three shrew subfamilies provides useful indications for the understanding of the origin and the evolution of these homologous tandemly repeated sequences. An asymmetry in the distribution of variants within the arrays, as well as the constant occurrence of shorter repeated sequences flanking only one side of the R2 arrays, could be related to asymmetry in the replication of each strand of the mtDNA molecule. The pattern of sequence and length variation within and between species, together with the capability of the arrays to form stable secondary structures, suggests that the dominant mechanism involved in the evolution of these arrays in unidirectional replication slippage.

Animals↗

PubMed2004

Cerebral correlates of varying ages of emotional memories.

OBJECTIVE: The purpose of the present study was to investigate the cerebral correlates of varying ages of emotional memories using quantitative electroencephalography. BACKGROUND: Recollection of emotional memories has often been used as a method of inducing emotional arousal in studies seeking to investigate the cerebral correlates of emotional arousal. However, the specific effects of the ages of the memories recalled on resulting changes in cerebral activity have not been investigated. METHOD: A total of 16 female undergraduates were asked to recollect an angry memory while quantitative electroencephalography was recorded. Following recollection, they were further asked to indicate the age of the memory recalled. RESULTS: The results indicated that significant correlations existed between ages of angry memories and changes in the magnitude of low beta (13 to 21 Hz) and high beta (21 to 32 Hz) at the right frontal, left temporal, and bilateral parietal regions of the brain. CONCLUSIONS: The results support an integration of the spreading activation and parallel distributed processing models of memory in predicting the cerebral effects of varying ages of emotional memories. Further, given the present findings, it may be important for investigators to determine the ages of the memories recalled so as to control or otherwise account for the effects of this potentially confounding variable.

Adolescent↗

PubMed1985

Effect of pacing on oxygen supply-to-consumption ratio in ischemic myocardium.

This study was performed to determine if the partially occluded myocardium could maintain its O2 supply-to-consumption ratio during atrial pacing. In 14 open-chest anesthetized dogs, the left anterior descending coronary artery was occluded to 50% of base-line flow, and in half of the dogs the hearts were paced to 50% above base-line heart rate. Blood flows were determined by use of microspheres before and after occlusion, and O2 supply-consumption variables were determined by use of microspectrophotometry. After occlusion in control and paced groups, blood flow was depressed in the ischemic region compared with the nonischemic region. In paced animals, blood flows in all regions were significantly higher compared with their respective values in nonpaced animals. After pacing, mean O2 consumption was 34% higher (53% in the occluded region) compared with control animals. The O2 supply-to-consumption ratio was similar in the occluded region of paced animals compared with the same region in controls. This ratio was lower in ischemic regions of both groups compared with their respective nonischemic regions. This indicates that, despite a reduced O2 supply-to-consumption ratio in the ischemic area, an unutilized reserve of flow exists.

Animals↗

PubMed1987

Oxypurinol limits myocardial stunning but does not reduce infarct size after reperfusion.

To explore the role of oxygen free radicals produced by the xanthine oxidase pathway on infarct size and left ventricular function, the effect of oxypurinol, an active metabolite of allopurinol and a potent noncompetitive inhibitor of xanthine oxidase, was assessed in a 90 min, closed-chest, canine preparation of occlusion-reperfusion. Animals were randomized to receive 25 mg/kg iv oxypurinol (n = 13) or saline (n = 13) 60 min after occlusion. Regional myocardial blood flow was measured with radioactive microspheres and regional ventricular function with contrast ventriculography. Hemodynamic variables, regional myocardial blood flow, and size of the occluded bed were similar in the two groups. Oxypurinol failed to reduce infarct size 24 hr after reperfusion when expressed as a percentage of the area at risk (36.3 +/- 4.9% vs 36.0 +/- 5.6%; p = NS). Both groups exhibited comparative radial shortening at baseline and similar degrees of dyskinesia 1 hr into occlusion (-6.6 +/- 1.2% vs -4.9 +/- 1.0%). However, oxypurinol-treated animals demonstrated an improved regional ventricular function at 3 hr after reperfusion (0.7 +/- 2.6% vs -2.8 +/- 2.0%) and a significant improvement at 24 hr (5.4 +/- 2.5% vs -3.2 +/- 1.7%; p less than .05). A reduced neutrophil infiltrate was observed in the border zone in treated animals. These findings suggest that oxygen free radicals derived from the xanthine oxidase pathway contribute to stunning of reversibly damaged myocardium but do not determine the final extent of myocardial necrosis in a canine preparation of reperfusion.

Animals↗

PubMed1995

[Left ventricular function in the acute phase of patients with myocardial infarction randomly treated with 750,000 or 1.5 million units of streptokinase].

PURPOSE: To compare the doses of 750,000 and 1.5 million units (U) of streptokinase (SK), relatively to the left ventricular (LV) systolic function analyzed through contrasted ventriculography. METHODS: We included 110 patients with acute myocardial infarction (AMI) within 6h of the onset (mean-age 60 years, 83.6% men), that were randomized to receive 750,000U of SK in 15 min (55 patients), or 1.5 million U in 30 min (55 patients). The study main goal was the comparison between the groups relatively to LV ejection fraction, global and regional shortening, obtained at the fifth day of the AMI. RESULTS: The 750,000 and 1.5 million groups were homogeneous relatively to 15 analyzed variables. Relatively to the main goal of the study, it was found respectively: a) ejection fraction analysis (median): 64% and 60.5% for the total population (p = 0.25, 95% CI -2.7 to 10), 64% and 57.5% for anterior AMI (p = 0.2, 95% CI -3.6 to 16.3), 65% and 65% for inferior AMI (p = 0.99, 95% CI -8.4 to 8.4); b) global shortening analysis: -2.53 and -2.66 for the total population (p = 0.3, 95% CI -0.47 to 0.87), -2.27 and -2.53 for anterior AMI (p = 0.18, 95% CI -0.3 to 1.4), -1.82 and 1.72 for inferior AMI (p = 0.9, 95% CI -0.82 to 0.75); c) regional shortening analysis: anterior AMI -2.6 and -2.67 (p = 0.47, 95% CI -0.7 to 1.5), inferior AMI -2.3 and -2.32 (p = 0.9, 95% CI -0.82 to 0.75). CONCLUSION: The dose of 750,000U was as efficacious as the 1.5 million relatively to LV systolic function, one of the best survival predictors of short-medium and long-term survival post AMI.

Aged↗

PubMed2001

[Thallium-201 scintigraphy and dobutamine echocardiography in the assessment of myocardial viability].

BACKGROUND: The possibility of differentiating viable from non-viable tissue among patients with severe coronary artery disease and severe left ventricular impairment entails relevant clinical and therapeutic implications since it may influence the indication of patient revascularization. To evaluate the presence of myocardial viability two techniques are available in the clinical setting: echocardiography with intravenous infusion of dobutamine and scintigraphy with myocardial perfusion with thalliem-201 by means of single-photon emission tomography. OBJECTIVE: To compare prospectively the value of these techniques for detecting viable myocardium. MATERIAL AND METHODS: Thirty-five patients with severe coronary disease and severe left ventricular dysfunction were included in the study. All patients underwent an echocardiogram using incremental doses of dobutamine, from 5 up to 40 micrograms/kg/min in three-minute periods. For thallium-201 scintigraphy the rest redistribution protocol with delayed images at 4 hours was used. The criteria for detecting viability were: a) for thallium-201, the presence of redistribution in delayed images and normal uptake at rest, and b) for dobutamine echocardiography, a sustained improvement in regional motion, biphasic response, and worsening. RESULTS: By considering the segmental improvement post-revascularization as "gold standard" of viability, the statistically significant variables in a logistic regression model and, therefore, predictors of segmental functional recovery were the biphasic response and the sustained response for dobutamine echocardiography and normal uptake at rest and redistribution in the delayed images for thallium-201. Taken together, the result was significant for the biphasic response of dobutamine echocardiography. CONCLUSIONS: The biphasic response with dobutamine echocardiography is the echocardiographic pattern that best predicts the functional recovery of the ischemic myocardium. A normal uptake and redistribution at four hours is the only scintigraphic pattern that can predict functional improvement. Of both patterns, the biphasic response is the best predictor of the functional recovery of the dysfunctional myocardium.

Cardiotonic Agents↗

PubMed2005

Severity of the ductal shunt: a comparison of different markers.

BACKGROUND: When the ductus arteriosus (DA) is patent, the ductal shunt is proportional to the ratio of left ventricular output (LVO) to systemic blood flow. Systemic blood flow can be estimated by measuring flow in the superior vena cava (SVC). OBJECTIVE: To re-evaluate the accuracy of standard echocardiographic markers of patent ductus arteriosus (PDA) using LVO/SVC flow ratio. METHODS: Prospective study. Preterm infants of 24-30 weeks gestational age and postnatal age less than 48 hours. The following echocardiographic criteria were measured: left atrial to aortic root ratio (LA/Ao); DA diameter by B mode and colour Doppler; mean and end diastolic flow velocity of the left pulmonary artery (LPA); LVO; SVC flow. RESULTS: Twenty three preterm infants were enrolled (median gestational age 28 weeks (range 24-30), median birth weight 840 g (500-1440)). The DA was closed in eight (mean (SD) LVO/SVC 2.4 (0.3)) and open in 15 (mean (SD) LVO/SVC 4.5 (0.6)). An LA/Ao ratio > or =1.4, a DA diameter > or =1.4 mm/kg, and a mean and end diastolic flow velocity of LPA respectively > or =0.42 and > or =0.20 m/s identified an LVO/SVC > or =4 with a sensitivity and a specificity above 90%. CONCLUSION: This study indicates that LA/Ao ratio, DA diameter, and mean and end diastolic flow velocity of the LPA are accurate markers of PDA. These standard echocardiographic variables are easy to measure and need less skill and resources than direct measurements of ductal shunt.

Blood Flow Velocity↗

PubMed1994

Early changes of the arterial carotid wall in uncomplicated primary hypertensive patients. Study by ultrasound high-resolution B-mode imaging.

Arterial hypertension is frequently responsible for arteriosclerotic damage in the carotid region. Nevertheless, there is as yet no general agreement that hypertension is correlated with lesions detected by noninvasive means in the carotid arteries. We studied, by noninvasive echotomographic technique, 70 uncomplicated primary hypertensive individuals without clinically evident end-organ complications and 30 normotensive matched control subjects to detect early lesions of carotid arteries. The presence of other cardiovascular risk factors was assessed, and heart structure and function were studied by echocardiography. Although hypertensive individuals were comparable to control subjects for other risk factors, they showed a marked increase in the thickness of the intimal-medial complex of the carotid wall (0.71 +/- 0.4 versus 0.56 +/- 0.2 mm, P < .001 in the right carotid and 0.83 +/- 0.3 versus 0.58 +/- 0.2, P < .003 in the left), in left ventricular mass (203 +/- 52 versus 176 +/- 37 g, P < .05), and in the prevalence of definite plaques of the carotid wall, both monolaterally and bilaterally (P < .003 by chi 2 test). Among the different factors contributing to the increase in thickness of the carotid artery wall, standing blood pressure, serum triglycerides, and age were found to be the best predictors (they accounted for about 16% of the variability, P < .005). These results indicate that carotid arteries of hypertensive individuals undergo degenerative changes, just as shown for hypercholesterolemic and diabetic patients in other studies. This supports the use of B-mode ultrasound imaging to detect early involvement of the carotid region before the appearance of any end-organ damage of hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Echocardiographic correlates of survival in patients with chest pain.

OBJECTIVES: This study sought to identify echocardiographic predictors of survival in patients with chest pain and to assess the utility of qualitative echocardiographic data in the prognostic stratification of this cohort. BACKGROUND: The potential usefulness of echocardiographic data in prognostic stratification of patients with acute chest pain is unclear, in part because of the qualitative nature of routinely available echocardiographic readings. METHODS: The study group comprised 513 patients who underwent transthoracic two-dimensional and Doppler echocardiography within 1 month of emergency department visits for acute chest pain. Clinical and electrocardiographic (ECG) data were recorded for these patients at the time of their initial evaluations, and echocardiographic data were subsequently obtained from the official hospital reports. Follow-up survival rate data were obtained from medical records or the Massachusetts Bureau of Vital Statistics. RESULTS: A mean of 28.5 months after the index visit, 102 patients (20%) had died, including 58 (57%) for whom the primary cause of death was cardiovascular. In analysis of routinely available qualitative echocardiographic data, left ventricular size and function, the presence of regional wall motion abnormalities, mitral regurgitation and structural abnormalities of the mitral valve were significant univariate correlates of both overall mortality and death from cardiovascular causes. Severe left ventricular dysfunction (adjusted rate ratio 3.8, 95% confidence interval [CI] 1.9-7.5) and moderate or severe mitral regurgitation (adjusted rate ratio 2.4, 95% CI 1.5-3.7) were independent predictors of mortality in a multivariate Cox regression analysis that adjusted for clinical and ECG variables. Moderate or severe left ventricular dysfunction and mitral regurgitation were predictors of mortality in the subset of patients without acute myocardial infarction. CONCLUSIONS: Qualitative echocardiographic reports of left ventricular dysfunction and mitral regurgitation were independent correlates of prognosis in patients with acute chest pain, including patients without acute myocardial infarction. Further data are needed to assess the generalizability of these findings and the implications for use of this diagnostic technology.

Acute Disease↗

PubMed1993

Sodium bicarbonate versus Carbicarb in canine myocardial hypercarbic acidosis.

The objective of this study was to compare the in vivo effects of sodium bicarbonate (NaHCO3) and Carbicarb infusion on regional contractile performance and acid-base status in the setting of hypercarbic acidosis. Animals (N = 9) were anesthetized and paralyzed using sodium pentothal, halothane, and pancuronium bromide, and mechanically ventilated with an air-O2 mixture so that arterial PO2 was > or = 300 mm Hg. Following beta-adrenergic blockade, alveolar ventilation was gradually reduced over a 50-minute period to increase arterial PCO2 to 60 to 80 mm Hg. Each of the following solutions was then infused in consecutive order directly into the left anterior descending artery coronary artery for 15 minutes: (1) 8.4% NaHCO3 at 2 mL/min; (2) 5% sodium chloride at 2 mL/min, equivalent to NaHCO3 in osmolality; (3) 6.3% Carbicarb at 0.5 mL/min, equivalent to NaHCO3 in buffer capacity; and (4) 6.3% Carbicarb at 2 mL/min, equivalent to NaHCO3 in volume. Regional stroke work analog (ultrasonic dimension transducers), interstitial myocardial pH (Khuri electrode), coronary blood flow (doppler flow probe), and hemodynamic/metabolic variables (heart rate, blood pressure, arterial and coronary venous blood gases) were measured at 1, 5, 10, and 15 minutes during each infusion and 10 minutes after the infusion was discontinued, ie, at 25 minutes. Animals were allowed to recover for 45 minutes between interventions. Values at each time point were compared with baseline for statistical significance. Small reductions in interstitial myocardial pH (P < .05) and stroke work (P > .05) were observed within 1 minute of NaHCO3 administration. Both parameters increased significantly from baseline levels thereafter, ie, interstitial myocardial pH at 5 minutes and stroke work at 15 minutes. Infusion of Carbicarb invariably was associated with an increase (P < .05) in interstitial myocardial pH. Stroke work increased (P < .05) during low-dose Carbicarb administration, but infusion of the higher dose was accompanied by a biphasic response, ie, an increase (P < .05) from 0 to 5 minutes, followed by a gradual decrease that achieved statistical significance 10 minutes after termination of the infusion. End-diastolic length was inversely proportional to changes in stroke work, and coronary blood flow varied directly with changes in coronary venous Pco2. Myocardial O2 consumption decreased (P < .05) during Carbicarb infusion, but changes during NaHCO3 did not reach statistical significance. Our findings lend support to the hypothesis that intramyocardial pH determines myocardial function independent of CO2 production by buffer therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Acidosis↗

PubMed2006

Correlation of PET and qEEG in normal subjects.

Positron emission tomography (PET) and quantitative electroencephalography (qEEG) were obtained in 15 normal male subjects with eyes closed at rest. Correlations between qEEG variables and regional metabolism were examined as an approach to investigating the metabolic and neuroanatomical basis of the generation of the EEG. Analogous to the neurometric approach to qEEG, a normative 2-fluoro-deoxyglucose voxel data base was developed for the PET image. The PET image was transformed to an idealized cylindrical set of coordinates to allow registration with the Talairach stereotactic atlas. PET regions of interest for the thalamus, the left and right temporal lobes, the medial frontal cortex and the dorsolateral prefrontal cortex were defined using Talairach coordinates and correlated to the QEEG. Salient findings included a negative correlation of thalamic metabolism to alpha power and a positive correlation of medial frontal cortical metabolism to delta EEG power. The significance of these findings is discussed with reference to the existing literature on the physiology of the generation of the EEG.

Adult↗