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Ambulatory blood pressure, nocturnal blood pressure reduction and plasma catecholamines.

OBJECTIVE AND DESIGN: Controversial data have been reported on plasma catecholamines in hypertensives. Aims of this study were to find whether 24-hour ambulatory blood pressure was correlated with circulating catecholamines and to investigate whether nocturnal blood pressure reduction was associated with baseline plasma catecholamines. Samples for catecholamine determination were obtained in 34 consecutive male subjects after a 30-minute rest and before ambulatory blood pressure monitoring. RESULTS: Hypertensive patients (n = 22; 24-hour blood pressure: 145 +/- 14/94 +/- 6 mm Hg) showed similar norepinephrine and epinephrine levels when compared with normotensives (n = 12; 24-hour blood pressure: 124 +/- 6/81 +/- 6 mm Hg), and higher dopamine values (hypertensives: 64.6 +/- 58; normotensives: 26.2 +/- 31 pg/ml; p < 0.05). A positive correlation was observed between dopamine and diastolic nocturnal blood pressure (p < 0.05) while a negative correlation was found between dopamine and nocturnal diastolic blood pressure reduction (p < 0.025). No significant relationship was observed between both norepinephrine and epinephrine, and 24-hour blood pressures. CONCLUSIONS: Since previous reports have documented malfunctioning of dopaminergic system in hypertension, the higher levels of circulating plasma dopamine found in hypertensive patients in the present study may account for a peripheral compensatory increase. The correlation between dopamine and nocturnal blood pressure fall seems to indicate that the impairment of dopaminergic system may influence the 24-hour blood pressure profile, affecting the nocturnal blood pressure reduction.

Adult↗

[The effect of preischemic blood sugar concentration on hemodynamics and regional organ blood flow during and following cardiopulmonary resuscitation (CPR) in swine].

UNLABELLED: Blood glucose alterations prior to cerebral ischaemia are associated with poor neurologic outcome, possibly due to extensive lactic acidosis or energy failure. Cerebral effects of hyper- or hypoglycaemia during cardiopulmonary resuscitation (CPR) are less well known. In addition, little information is available concerning cardiac effects of blood glucose alterations. The aim of this study was to evaluate the effects of pre-cardiac-arrest hypo- or hyper-glycaemia compared to normoglycaemia upon haemodynamics, cerebral blood flow (CBF) and metabolism (CMRO2), and regional cardiac blood flow during CPR subsequent to 3 min of cardiac and respiratory arrest and after restoration of spontaneous circulation. METHODS: After approval by the State Animal Investigation Committee, 29 mechanically ventilated, anaesthetised pigs were instrumented for haemodynamic monitoring and blood flow determination by the radiolabeled microsphere technique. The animals were randomly assigned to one of three groups: in group 1 (n = 9) blood glucose was not manipulated; in group II (n = 10) blood glucose was increased by slow infusion of 40% glucose to 319 +/- 13 mg/dl; in group III (n = 10) blood glucose was lowered by careful titration with insulin to 34 +/- 2 mg/dl. After 3 min of untreated ventricular fibrillation and respiratory arrest, CPR (chest compressor/ventilator (Thumper) and epinephrine infusion) was commenced and continued for 8 min. Thereafter, defibrillation was attempted, and if successful, the animals were observed for another 240 min. Cerebral perfusion pressure (CPP), CBF, CMRO2, coronary perfusion pressure (CorPP), and regional cardiac blood flow were determined at control, after 3 min of CPR, and at 10.30, and 240 min post-CPR. RESULTS: In group 1. 4/9 animals (44%) could be successfully resuscitated; in group II 4/10 (40%); and in group III 0/10 (0%). Prior to cardiac arrest, mean arterial pressure, CPP, and CorPP in group III were significantly lower compared to groups I and II. In group I. CPP during CPR was 26 +/- 6 mmHg; CBF 31 +/- 9 ml/ min/100g CMRO2 3.8 +/- 1.2 ml/ min/100 g; CorPP 18 +/- 5 mmHg; and left ventricular (LV) flow 35 +/- 15 ml/min/100 g. In group II; CPP = 21 +/- 5; CBF 21 +/- 7; CMRO2 1.8 +/- 0.8; CorPP 16 +/- 6; and LV flow 22 +/- 9; and in group III: CPP 15 +/- 3; CBF 11 +/- 8; CMRO2 1.5 +/- 1.1; CorPP 4 +/- 2; and LV flow 19 +/- 10. During the 240-min post-resuscitation period, there were no differences in CBF, CMRO2, or LV flow between groups I and II. CONCLUSION: Hypoglycaemia prior to cardiac arrest appears to be predictive for a poor cardiac outcome, whereas hyperglycaemia does not impair resuscitability compared to normoglycaemia. In addition, hyperglycaemia did not affect LV flow, CBF, or CMRO2. However, it has to be kept in mind that haemodynamics and organ blood flow do not permit conclusions with respect to functional neurologic recovery or histopathologic damage to the brain, which is very likely to be associated with hyperglycaemia.

Anesthesia↗

Blood pressure evaluation by noninvasive and traditional methods. Consistencies and discrepancies among photoplethysmomanometry, office sphygmomanometry, and ambulatory monitoring. Effects of blood pressure measurement.

Three hundred eight outpatients referred for hypertension were studied. A continuous beat-to-beat noninvasive recording (Finapres) of blood pressure evaluated the blood pressure increase (9 mm Hg systolic and 4 mm Hg diastolic) induced by office sphygmomanometry. Thereafter, patients underwent a 24-h ambulatory blood pressure monitoring. The evaluation against Finapres showed that office sphygmomanometry overestimates the systolic blood pressure by 3 +/- 36 mm Hg (mean +/- 2 SD) and the diastolic blood pressure by 15 +/- 25 mm Hg (mean +/- 2 SD). Blood pressure monitoring showed similar discrepancies. On the basis of both monitoring (normalcy defined from a population of 550 normotensive subjects) and office sphygmomanometry, patients were considered normotensive, hypertensive (either untreated or under active drug treatment), white coat hypertensive (monitoring below the 95th percentile and sphygmomanometry more than 140/90 mm Hg, either untreated or under active drug treatment), and reverse white coat patients (monitoring over the 95th percentile and sphygmomanometry less than 140/90 mm Hg). Patients showed different levels of alert reaction (the highest in white coat hypertensive and the lowest in reverse white coat hypertensive patients), and a similar increase in blood pressure induced by conventional sphygmomanometry. During initial readings of ambulatory monitoring, blood pressure decreased from the first reading to the third reading. This decrease is related to the increase of blood pressure under sphygmomanometry. Caution should be paid in interpreting results of sphygmomanometry (error level in the single patient as high as +/- 40 mm Hg), and interpreting and averaging results of the first hour of blood pressure monitoring (variably affected by the alert reaction to the clinical environment).

Adolescent↗

UV-visible spectrophotometric approach to blood typing II: phenotyping of subtype A2 and weak D and whole blood analysis.

BACKGROUND: A recently introduced quantitative blood typing approach uses antibody-induced changes in the UV-visible spectra of blood. Changes in the blood spectra's slope, caused by RBC agglutination, are translated into a numerical agglutination index (AI). Comparing the AI value against an established threshold yields a "yes and/or no" output from which to determine the phenotype. The efficacy and flexibility of this approach with whole blood use and the ability to analyze weak D, A2, and A2B were examined. STUDY DESIGN AND METHODS: Two hundred randomly selected blood bank donor samples were coded and forward typed directly from whole blood by using the spectrophotometric analysis. Reverse grouping on plasma from each sample was carried out with a new modified procedure by using higher ratios of plasma to RBCs. Results were compared to typing by an FDA-cleared automated typing system. Twenty-seven weak D samples, 15 A2 and 12 A2B, were similarly analyzed from whole blood. PEG improved detection of weak D, A2 and A2B subtypes. RESULTS: All two hundred coded samples were accurately typed, yielding identical results to the blood bank analysis in both forward and reverse grouping. All the weak D samples and A2 and A2B samples were clearly identified, having AIs above the type threshold indicator value. CONCLUSION: Spectrophotometric blood typing successfully phenotyped ABO and D in 200 whole blood samples. Reverse grouping of plasma was equally successful. The same method can identify weak D and A2 and A2B subtypes.

ABO Blood-Group System↗

A blood ordering strategy for hospital blood banks derived from a computer simulation.

The ultimate goal of a hospital blood bank inventory control programs is to reduce wastage of blood products and unnecessary use of laboratory services without jeopardizing patient safety. The development of a practical blood ordering policy at the hospital level is an integral part of any such program. In order to explore various blood ordering options in detail, a computer simulation of a hospital blood inventory was used to assess the impact on blood band performance measures of reductions in group O and non-group-O levels from baseline levels, assuming both a 21-day and 35-day shelf life. On the basis of data derived from this study showing that such inventory reductions accompanied by partial protection of the group O inventory will not result in significant shortages, a practical strategy was developed for establishing optimal target inventory levels for a hospital on an empirical basis. These target levels can serve as a guide for subsequent blood ordering. A step-by-step approach for analyzing a hospital blood inventory control program is then suggested, accompanied by an action plan for implementing change which incorporates the experimentally-derived blood ordering strategy. Adherence to this plan should result in a low outdate rate, a reduction in unnecessary cross-matching, and greater availability of blood for those patients with a legitimate need for it.

ABO Blood-Group System↗

Blood lead, blood pressure, and hypertension in perimenopausal and postmenopausal women.

CONTEXT: Lead exposures have been shown to be associated with increased blood pressure and risk of hypertension in older men. In perimenopausal women, skeletal lead stores are an important source of endogenous lead exposure due to increased bone demineralization. OBJECTIVE: To examine the relationship of blood lead level with blood pressure and hypertension prevalence in a population-based sample of perimenopausal and postmenopausal women in the United States. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional sample of 2165 women aged 40 to 59 years, who participated in a household interview and physical examination, from the Third National Health and Nutrition Examination Survey conducted from 1988 to 1994. MAIN OUTCOME MEASURES: Associations of blood lead with blood pressure and hypertension, with age, race and ethnicity, cigarette smoking status, body mass index, alcohol use, and kidney function as covariates. RESULTS: A change in blood lead levels from the lowest (quartile 1: range, 0.5-1.6 micro g/dL) to the highest (quartile 4: range, 4.0-31.1 microg/dL) was associated with small statistically significant adjusted changes in systolic and diastolic blood pressures. Women in quartile 4 had increased risks of diastolic (>90 mm Hg) hypertension (adjusted odds ratio [OR], 3.4; 95% confidence interval [CI], 1.3-8.7), as well as moderately increased risks for general hypertension (adjusted OR, 1.4; 95% CI, 0.92-2.0) and systolic (>140 mm Hg) hypertension (adjusted OR, 1.5; 95% CI, 0.72-3.2). This association was strongest in postmenopausal women, in whom adjusted ORs for diastolic hypertension increased with increasing quartile of blood lead level compared with quartile 1 (adjusted OR, 4.6; 95% CI, 1.1-19.2 for quartile 2; adjusted OR, 5.9; 95% CI, 1.5-23.1 for quartile 3; adjusted OR, 8.1; 95% CI, 2.6-24.7 for quartile 4). CONCLUSIONS: At levels well below the current US occupational exposure limit guidelines (40 microg/dL), blood lead level is positively associated with both systolic and diastolic blood pressure and risks of both systolic and diastolic hypertension among women aged 40 to 59 years. The relationship between blood lead level and systolic and diastolic hypertension is most pronounced in postmenopausal women. These results provide support for continued efforts to reduce lead levels in the general population, especially women.

Adult↗

The effect of denbufylline on the viscosity of rat whole blood and on the deformability (filterability) of rat blood cell suspensions.

The novel alkylxanthine, denbufylline [1,3-di-n-butyl-7-(2-oxopropyl)-xanthine] has been examined, in vitro, for effects on the viscosity of rat whole blood and on the filterability of rat blood cell suspensions. For comparison, pentoxifylline was also examined for rheological activity. Denbufylline reduced the viscosity of whole blood at all shear rates utilised, up to 128.5 s-1. The effect was, however, more pronounced at a low (0.7 s-1) than at a high (94.5 s-1) shear rate indicating that the compound reduces blood cell aggregation and increases blood cell deformability. Denbufylline also increased the filterability of blood cell suspensions. This is further evidence that the compound increases the deformability of blood cells. Denbufylline elevated the filterability of both pure erythrocyte and mixed erythrocyte/leucocyte suspensions, the effect being greatest with the latter. This suggests that denbufylline may influence the deformability of both red and white blood cells. However, the effect on white blood cells, under the experimental conditions employed, is apparently more marked. Pentoxifylline also reduced the viscosity of rat whole blood and increased the filterability of rat blood cell suspensions. However, denbufylline was 10-100-fold more potent in these tests than pentoxifylline.

Animals↗

Distribution of sodium valproate in normal whole blood and in blood from patients with renal or hepatic disease.

Sodium valproate at a concentration of 300 mumol/l in whole blood, partitioned between the red blood cell and plasma to produce a red blood cell/plasma partition ratio of 0.20. Red blood cell uptake was proportional to percent free drug in plasma and uptake was maximal when plasma was replaced by buffer, producing a red blood cell/buffer ratio of 0.87. Reduction of plasma protein binding by plasma dilution, by increasing the total sodium valproate plasma concentration, or by renal or hepatic disease in 24 patients, caused a predictable rise in red blood cell uptake of drug. The red blood cell represented a relatively small compartment for free sodium valproate in blood, however uptake of the drug into this compartment increased considerably in states of reduced plasma protein binding. Because the concentration of drug in the red blood cell reflects free drug concentration in plasma, the red blood cell may serve as an indicator of free drug changes in blood.

Adult↗

Reference data for ambulatory blood pressure monitoring: what results are equivalent to the established limits of office blood pressure?

In 1039 subjects ambulatory blood pressure monitoring was performed to define threshold values, which are equivalent to the established limits of the office blood pressure. Mean values and proportions of elevated single readings were correlated to office blood pressure by regression analyses. To avoid impact of varying sleeping periods on 24 h blood pressure, only daytime readings were considered. Correlations between average daytime blood pressure and office blood pressure were linear: Mean daytime values of 135 mmHg (systolic) and of 84 mmHg (diastolic) were equivalent to the casual blood pressure limits of 140 mmHg and 90 mmHg. Correlations between percentages of elevated single readings and office blood pressure were nonlinear: Proportions of 25% systolic readings greater than 140 mmHg and of 17% diastolic readings greater than 90 mmHg were equivalent to casual blood pressure limits of 140 mmHg and 90 mmHg. On the basis of the regression equations, any result of ambulatory blood pressure recording during daytime can now be evaluated in terms of the established standards of office blood pressure.

Blood Pressure Monitors↗

Serum zinc and copper levels in the maternal blood and cord blood of neonates.

Estimation of serum zinc and copper in the maternal blood and cord blood of neonates was carried out to correlate the trace metals in the neonates and their mothers in relation to gestational age and birth weight. Sixty-five healthy neonates, both term and preterm and their mothers were selected. This cross sectional study was done at Azimpur Maternity Centre, Dhaka Medical College Hospital and Chemistry Division, Atomic Energy Centre, Dhaka, Bangladesh from July 1997 to June 1998. The estimation of trace metals was carried out by Atomic Absorption Spectrophotometry (AAS). The mean serum zinc levels in the maternal blood and cord blood were 0.47 +/- 0.24 microgram/ml and 0.85 +/- 0.33 microgram/ml respectively and the mean copper levels in the maternal blood and cord blood were 1.37 +/- 0.62 micrograms/ml and 0.31 +/- 0.32 microgram/ml respectively. Cord blood zinc level was significantly higher and cord blood copper level was significantly lower than the corresponding maternal blood levels. There was no significant correlation between gestational age and serum zinc levels in the cord or maternal blood. But significant inverse correlation was found between gestational age and serum levels of copper in the maternal and cord blood.

Bangladesh↗

Comparison of blood gas values in arterial and venous blood.

OBJECTIVE: To compare pH and PCO2 values of simultaneously obtained arterial, arterialized capillary, and venous blood samples and also to compare oxygen saturation (ASaO2) measured in arterial blood and oxygen saturation by pulse oximetry (PSaO2). METHODS: Prospective study was done in the children admitted in the Pediatric Intensive Care Unit of Christian Medical College Hospital Vellore, requiring critical care. All the three blood gas samples (arterial, capillary and venous) were taken simultaneously and analyzed. Oxygen saturation by pulse oximetry was also recorded. RESULTS: 50 children aged 14 days to 12 years were included in the study. Arterial and capillary pH values were highly correlated (r2=0.9024, p<0.0001). Out of 16 children with arterial acidosis 9(56%) were identified by capillary blood gas. Arterial and venous pH values also showed good correlation (r2=0.8449, p<0.0001). The PCO2 values of arterial and capillary blood gases were found to be highly correlated (r2=0.9534, p<0.0001). The capillary blood gas accurately reflected the arterial PCO2 in 41 (82%) patients. Arterial and venous blood gas PCO2 values had less correlation (r2=0.5917, p=0.011). The arterial oxygen saturation (ASaO2) and oxygen saturation by pulse oximetry (PSaO2) were correlated moderately (r2=0.7241, p<0.0001). CONCLUSION: Even though arterial blood gas analysis is the gold standard, and when an arterial blood gas sample cannot be obtained, a combination of arterialized capillary blood gas and pulse oximetry can be effectively used in acutely ill children of all ages. Venous samples have a good correlation with arterial samples for pH but are not useful for monitoring blood gas status in acutely ill children.

Acidosis, Respiratory↗

Effects of intraoperative autologous blood donation and tepid temperature cardiopulmonary bypass on blood system.

The effects of the intraoperative autologous blood donation and tepid temperature cardiopulmonary bypass (CPB) on blood system were investigated. Twenty-four patients with rheumatic heart valve diseases scheduled for open heart surgery were selected and divided randomly into group A (intraoperative autologous blood donation and tepid temperature, nasopharyngeal temperature was at 32-34 degrees C during CPB) and group B (control, nasopharyngeal temperature was at 25-28 degrees C during CPB). The plasmatic concentrations of GMP-140 and D-Dimer and the plasmatic activities of 6-keto-PGF1 alpha and AT-III were measured by using ELISA or substrate luminescence techniques before operation, at the end of CPB, after discontinuation of CPB and postoperatively. Red blood cell count, platelet count, hematocrit, the amount of blood drainage and the amount of blood transfusion needed were measured or recorded postoperatively. The results showed the plasmatic concentrations of GMP-140 and D-Dimer in group A were significantly less (P < 0.05) than those in group B during and after operation. The activity of 6-keto-PGF1 alpha in group A was higher (P < 0.05) than that in group B during and after operation. The AT-III activity in group A was less (P < 0.05) during CPB but higher 30 min after discontinuation of CPB than that in group B. The amount of postoperative blood loss (283 +/- 166 versus 722 +/- 194 ml, P < 0.01) and amount of blood transfusion (816 +/- 126 versus 1443 +/- 678 ml, P < 0.01) in group A were significantly less than those in group B, respectively. The red blood cell count, platelet count and hematocrit in group A were significantly higher than those in group B after operation. The results suggests intraoperative autologous blood donation and tepid temperature have a good protection on blood system and can reduce postoperative non-surgical bleeding.

Adult↗

[Continuous blood glucose monitoring: the acute effect of acarbose on blood glucose variations].

BACKGROUND: Acarbose, a pseudo-tetrasaccharid, inhibits intestinal alpha-glucosidases, effects a reduction of postprandial hyperglycemia and is particularly used in the treatment of patients with type-2 diabetes mellitus. The aim of the study is to analyse by a continuous blood glucose measurement the acute effect of acarbose after a carbohydrate loading and during a 12 hours period. PATIENTS AND METHODS: We examined 10 patients with type-2 diabetes mellitus (mean age 59.2 +/- 3.79, HbA1 9.2 +/- 0.26%) treated with sulfonylureas and/or insulin after a carbohydrate meal and 12 hours during daytime, to test whether the first application of acarbose influences the mean blood glucose or the blood glucose amplitudes. Four measurements were enrolled using a portable continuous blood glucose sensor (Glucosensor, unitec Ulm). A measurement after a carbohydrate loading (Fresubin, 500 kcal, 69 g carbohydrate) with 100 mg acarbose (Glucobay) was followed by a 12-hour measurement during daytime with 3 x 100 mg acarbose and standard diet. These measurements were repeated without acarbose. RESULTS: After a carbohydrate loading, the mean blood glucose level (AUC 44,320 +/- 10,660 with acarbose vs. 61,390 +/- 12,590 without acarbose; mean + SD; p = 0.004) decreased by 28%. During daytime blood glucose levels were not significantly decreased (165.7 +/- 50.3 mg/dl vs 183.7 + 67.4 mg/dl; p = 0.1) although the postprandial blood glucose amplitudes after the 3 meals were reduced significantly (85.90 +/- 24.6 mg/dl vs 106.5 +/- 20.5 mg/dl; p = 0.02). CONCLUSIONS: Continuous blood glucose monitoring indicated that acarbose diminished mean blood glucose levels after a carbohydrate loading in patients with type-2 diabetes mellitus, but not during 12 hours of standard diet, although blood glucose amplitudes decreased. Long-term improvements of metabolism by acarbose may therefore be related to the reduction of blood glucose amplitudes which is likely to reduce toxic effects of glucose on islet cell function.

Acarbose↗

Cocaine potentiates the blood pressure and cerebral blood flow response to norepinephrine in rats.

Acute drug-induced hypertension is known to have adverse consequences on the cerebral vasculature. Cocaine abuse has been reported to be associated with an increased frequency of hemorrhagic or ischemic stroke. The purpose of this study was to determine whether cocaine alters the blood pressure or cerebral blood flow response to exogenous norepinephrine. A craniectomy was made over the parietal cortex in rats and cortical blood flow changes were measured using laser-Doppler flowmetry. Ten minutes after cocaine (1 mg/kg, i.v.) or saline, increasing doses of norepinephrine (0.01-10 micrograms/kg, i.v.) were given by bolus injection and changes in blood pressure and flow were monitored. Cocaine produced a transient 27 +/- 5% increase in blood pressure and a 38 +/- 9% increase in blood flow. Cocaine significantly potentiated the blood pressure and cerebral blood flow responses produced by submaximal pressor doses of norepinephrine (0.01-0.6 microgram/kg, i.v.). In summary, cocaine causes a rapid, transient increase in blood pressure and cortical blood flow and potentiates the magnitude and duration of the pressure and flow response to norepinephrine. Repetitive blood pressure elevations in cocaine abusers is one of the proposed mechanisms leading to damage of cerebral vessels. These results may be relevant to an increased frequency of cerebrovascular accidents in cocaine-abusing individuals.

Analysis of Variance↗

Relationship between the hydralazine-induced changes in murine tumor blood supply and mouse blood pressure.

The relationship between hydralazine-induced changes in blood pressure and tumor blood flow was investigated in restrained but non-anesthetized CDF1 mice bearing C3H/Tif foot tumors. Mean arterial blood pressure measurements were made using the procedure of carotid cannulation, and tumor blood flow was estimated using laser Doppler flowmetry. Hydralazine doses from 0.1 to 5.0 mg/kg were tested. Following hydralazine administration the maximum changes in blood pressure and blood flow were apparent within 10-15 min and were maintained for at least 30 min after injection. Blood pressure decreased with increasing hydralazine dose, achieving a maximum reduction of 50% at 2.5 mg/kg. Tumor blood flow was found to be increased by 30% at the lowest hydralazine dose (0.1 mg/kg), even though blood pressure was decreased by 10% at this dose. At hydralazine doses producing a 15% or greater blood pressure drop, blood flow decreased, reaching an 80-90% reduction between 2.5 and 5.0 mg/kg.

Animals↗

Comparison of blood counts in splenic, renal and mesenteric arterial and venous blood in post-pubertal rabbits.

OBJECTIVES: To compare blood counts between arterial and venous blood to and from visceral organs and indirectly look into the function of the organs. METHODS: Splenic, renal and superior mesenteric arterial and venous blood samples were obtained from the arteries and veins in 38 post-pubertal rabbits and blood profile, including complete and differential blood counts, haemoglobin concentration and haematocrit, were measured with an automatic haematology analyser. RESULTS AND CONCLUSIONS: The rabbit spleen released a large amount of leucocytes (both lymphocytes and granulocytes) into the splenic venous blood (a venous increase of 33% in total leucocyte count), and also received more leucocytes (36-58% more in terms of concentration) from the artery than the kidney or intestine. Significantly fewer red blood cells were present in the renal venous blood than in the arterial blood (a venous reduction of 5% in erythrocyte count), but it remains to be clarified why and how the reduction was induced. More than 3-4% of water might be taken into the mesenteric venous blood during microcirculation (a venous reduction of 3-4% in erythrocyte-related parameters) and a significant number of leucocytes (mainly large leucocytes) in the mesenteric blood capillaries might migrate into the surrounding intestinal tissue (a venous reduction of 13% in leucocyte count).

Animals↗

Ultrasensitive detection of domoic acid in mouse blood by competitive ELISA using blood collection cards.

Domoic acid (DA), an analog of the excitatory amino acid glutamate, is produced by the diatom genus Pseudo-nitzschia and acts as a neurotoxin in humans. During diatom blooms, DA can contaminate shellfish, as well as other filter feeding organisms, and can be transferred by ingestion to higher trophic levels, including marine mammals and humans. The prevalence of this algal toxin and its effects on protected species makes measurement of domoic acid in living animals a necessary biomonitoring tool for the near future. Blood collection cards have already been used for the sampling, extraction and detection of brevetoxin in blood from exposed laboratory animals and, more recently, marine mammals. However, a difficulty unique to measuring DA in blood is the rapid rate (>95% in 2h) at which it is cleared from blood. To meet this challenge, a direct competitive ELISA (cELISA), a method of detection with extremely high sensitivity and specificity, was used to analyze the blood of DA-exposed mice after extraction from the blood collection cards. More than 99% of DA was cleared from blood within 4h post dosage; however, domoic acid was still quantifiable (>0.7ngml(-1)) at 4h from blood spot extracts and still detectable at 24h when compared to control blood spots. By using this highly sensitive assay in conjunction with the use of blood spot cards for easy blood sample extraction, this method could be a very effective means of biomonitoring domoic acid in marine mammals in the field, as well as human populations.

Animals↗

Does retrograde warm blood cardioplegic perfusion provide better protection of ischemic areas than antegrade warm blood cardioplegic perfusion? A magnetic resonance study in pig hearts.

OBJECTIVE: The purpose of this study was to determine whether retrograde continuous normothermic blood cardioplegic perfusion provides better protection to ischemic areas of the left and right ventricles than does antegrade continuous normothermic blood cardioplegic perfusion. Localized phosphorus 31 magnetic resonance spectroscopy was used to monitor the changes in energy metabolism and intracellular pH in the ventricles of pig hearts. METHODS: Ten isolated pig hearts received 20 minutes of antegrade continuous normothermic blood cardioplegic perfusion for collection of control (baseline) data, followed by 60 minutes of either antegrade continuous normothermic blood cardioplegic perfusion (n = 5) or retrograde continuous normothermic blood cardioplegic perfusion (n = 5) with occlusion of the left anterior descending and the right coronary arteries. The hearts were then subjected to antegrade continuous normothermic blood cardioplegic perfusion for 20 minutes. The perfusion pressures were maintained between 80 and 100 mm Hg and between 38 and 43 mm Hg during antegrade and retrograde continuous normothermic blood cardioplegic perfusions, respectively. Intracellular pH and creatine phosphate, inorganic phosphate, and adenosine triphosphate levels were measured continuously in each ventricle by means of localized phosphorus 31 magnetic resonance spectroscopy with 2 surface coils. RESULTS: Both antegrade and retrograde continuous normothermic blood cardioplegic perfusion resulted in a significant increase in inorganic phosphate level and decreases in creatine phosphate level, adenosine triphosphate level, and intracellular pH. No significant differences in these changes were observed between the two groups. The creatine phosphate and adenosine triphosphate levels were significantly lower in the right ventricle than in the left ventricle during retrograde continuous normothermic blood cardioplegic perfusion. On reperfusion, the inorganic phosphate level, creatine phosphate level, and intracellular pH recovered completely; however, no recovery in the adenosine triphosphate level was seen in the ventricles of either group. CONCLUSIONS: Retrograde continuous normothermic blood cardioplegic perfusion does not provide better protection to ischemic areas of the ventricles than does antegrade continuous normothermic blood cardioplegic perfusion under our experimental conditions.

Adenosine Triphosphate↗