A case of dilated cardiomyopathy caused by myocardial microinfarcts in the course of polycythemia vera

This article presents a case of 45-year-old man with polycythemia vera non diagnosed before. The first symptom of polycythemia vera was acute congestive heart failure which suggested diagnosis of myocarditis. Polycythemia vera was confirmed by raised hematocrit, significantly increased platelet count, normal oxygen saturation, score for leukocyte alkaline phosphatase (LAP)-130 and splemomegaly. Echocardiography revealed left ventricular histological. Coronary arteriography showed normal coronary arteries. Finding of histological examination of the endomyocardial biopsy were described as necrosis of myocytes and abnormal blood flow in very small coronary vessels. It was the main reason of dilated cardiomyopathy caused by microinfarcts in polycythemia vera. Hematological parameters were reduced to normal levels after hydroxyurea treatment. Digitalis and ACE-inhibitor therapy quickly improved cardiovascular status from III to II NYHA class.     

Adenylosuccinase deficiency: clinical and biochemical findings in 5 Czech patients

Polycythemia and hyperhomocysteinemia are risk factors for thrombosis. Since red blood cells actively metabolize methionine to homocysteine, we investigated whether or not patients with polycythemia have increased plasma levels of homocysteine, which might contribute to their increased thrombotic risk. In ten patients with polycythemia, the plasma homocysteine levels were measured before phlebotomy, three days after the procedure and 1-2 months later. The baseline mean plasma homocysteine levels in patients (9.7 +/- 1.6 mumol/L [+/-SD]) did not differ significantly from that found in 30 sex- and age-matched healthy controls (12.2 +/- 6.9). Despite a fall in the patients' mean [+/-SD] hematocrit from 0.50 +/- 0.02 at baseline to 0.47 +/- 0.03 three days after phlebotomy (significant at 95%) and to 0.48 +/- 0.02 after 1 to 2 months (not significant), the mean plasma homocysteine levels did not change significantly (9.9 +/- 2.3 mumol/L at 3 days and 9.7 +/- 2.1 mumol/L at 1-2 months). It is unlikely that high plasma homocysteine levels contribute to the increased thrombotic risk of polycythemic patients.     

Calculating catecholamine extraction from plasma

Surgery in the presence of uncontrolled polycythemia vera is associated with a high incidence of perioperative hemorrhage and postoperative venous thromboses. Control prior to surgery reduces the frequency of perioperative complications. A 73-year-old women suffering from polycythemia vera was scheduled for subtotal gastrectomy. Her platelet count before surgery was slightly elevated but bleeding time was prolonged. To manage the current case of polycythemia vera, hydroxyurea was effective for the control of hematocrit and transfusion of platelet concentrates was effective for hemostasis.     

Distribution and role of aspartate in the nervous system of the chaetognath Sagitta

Forty-nine female workers in the shoemaking industry, exposed to a solvent mixture containing benzene and twenty-seven non-exposed controls, were investigated. Concentrations of benzene and toluene in the working atmosphere, as well as benzene and toluene in blood and phenols in pre- and post-shift urine as parameters of biological monitoring, were determined. In order to assess hematotoxic risk, a complete blood cell count with differential, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, reticulocytes, serum iron, alkaline phosphatase in neutrophils and red blood cell glycerol lysis time were determined in all subjects. Benzene concentrations in the workplace atmosphere at the shoemaking factory ranged from 1.9 to 14.8 ppm (median = 5.9). Significant difference in benzene in blood (p = 0.005) and phenol in post-shift urine (p = 0.003) between exposed workers and controls confirmed exposure to benzene. Hemoglobin level (p = 0.02) and mean corpuscular hemoglobin concentration (p = 0.0002) in the shoe workers were lower, and band neutrophils (p = 0.005) and mean corpuscular volume (p = 0.03) higher, than in controls. Red blood cell glycerol lysis time was significantly higher (p = 0.000001) in shoe workers (X +/- SD = 41.6 +/- 8.9) than in controls (X +/- SD = 31.1 +/- 6.5) and showed a significant correlation with exposure biomarkers. The results confirm that benzene exposure below 15 ppm may produce qualitative abnormalities, particularly macroerythrocytosis and increased red cell glycerol resistance, in the absence of an overt quantitative decrease in circulating blood cells. Increased resistance to the hemolytic action of glycerol is a potentially useful biological monitoring procedure in medical surveillance of benzene exposed workers. The results of this study suggest that potential threshold concentration for hematologic effects of benzene is lower than 15 ppm.     

Poly(ADP-ribose) polymerase gene expression status and genomic instability in human breast cancer

OBJECTIVE: To compare point-of-care results obtained from an on-site hemocytometer with values provided by an institutional laboratory instrument. DESIGN: A prospective laboratory evaluation. SETTING: The central laboratory and cardiac surgical intensive care unit of a university-affiliated tertiary care center. PATIENTS: Normal range comparison was performed using blood specimens routinely obtained from 48 hospitalized patients for complete blood count analysis. The second evaluation was performed on blood specimens routinely obtained (in the intensive care unit) after cardiac surgery involving extracorporeal circulation in a series of 187 consecutive patients. MEASUREMENTS AND MAIN RESULTS: Hemoglobin concentration, platelet count, mean corpuscular volume, mean platelet volume, and red and white blood cell counts were measured with both on-site (MD 16, Coulter Electronics, Hialeah, FL) and laboratory (STKS, Coulter Electronics) instruments. Hematocrit and red cell distribution width were calculated using measured variables. Blood specimens were obtained from two distinct patients series. To evaluate measurement values within the normal range, a series of 48 routinely obtained blood specimens for complete blood count analysis in our institutional laboratory were utilized for concurrent analysis with the on-site hemocytometer. To evaluate measurement values out of the normal range, a second comparison involved measurements performed on blood specimens obtained in the cardiac surgical intensive care unit for complete blood count analysis. Linear regression demonstrated good correlations between on-site and laboratory hemoglobin concentration (r2 = .97), hematocrit (r2 = .95), platelet count (r2 = .97), mean corpuscular volume (r2 = .91), red cell distribution width (r2 = .80), and red (r2 = .95) and white (r2 = .96) blood cell count results. A marginal correlation was observed between mean platelet volume values (r2 = .47). Bias analysis (mean +/- 2 SD) demonstrated similar measurements between on-site and laboratory hemoglobin concentration, hematocrit, platelet count, red blood cell count, white blood cell count, mean platelet volume, mean corpuscular volume, and red cell distribution width. CONCLUSIONS: On-site hemoglobin concentration, hematocrit, white blood cell count, red blood cell count, red cell distribution width, and platelet count values compare well with those results obtained from the laboratory. The MD 16 hemocytometer (Coulter Electronics) provides on-site hematologic results that can provide an accurate and rapid quantitative assessment of platelets, and red and white blood cells. Rapid access to information obtained from this type of system may be clinically useful, especially in critically ill patients.     

Impact of ultrafiltration on blood use for atrial septal defect closure in infants and children

BACKGROUND: Infants and children undergoing open cardiac operations have a high incidence of blood product transfusion. Ultrafiltration has been shown to reverse hemodilution and improve myocardial function and hemodynamics after cardiopulmonary bypass (CPB). METHODS: The effect of ultrafiltration on the amount of blood transfusion and hospital charge in 39 consecutive patients who underwent elective atrial septal defect repair was examined. Patients in group I (n=26) had a conventional cardiopulmonary circuit prime with blood, whereas 13 patients had bloodless prime (group II). Ultrafiltration was used immediately after weaning from CPB in group II. The patients in group I received blood products after discontinuation of CPB to achieve a hematocrit of 30%. The amount of blood product used, hematocrit immediately after CPB and on arrival in intensive care unit, postoperative hemodynamics and saturations, total operating room charge, blood charge, hospital stay, and hospital charge were compared. RESULTS: Mean body weight (15.8 kg in group I versus 17.5 kg in group II) and preoperative hematocrit values (35.6% in group I versus 34.2% in group II) were similar. Mean hematocrit immediately after CPB was 22% and 14% in group I and II, respectively (p < 0.0001). The mean hematocrit upon arrival to the intensive care unit was 34% in group I and 22% in group II (p < 0.0001). The amount of blood product transfusion was 32 mL/kg in group I and 3 mL/kg in group II patients (p < 0.0001). The patients in group II had significantly less blood bank charges; however, operating room charges and total hospital charges were similar between the two groups. CONCLUSIONS: Elective atrial septal defect repair was performed with no blood product transfusion without increased morbidity or hospital stay. Ultrafiltration can be used to reverse hemodilution resulting from a bloodless CPB prime without an increase in hospital charge.     

Elderly patients in chronic hemodialysis: risk factors for left ventricular hypertrophy

In the past few years in Western countries, there has been an increasing proportion of elderly patients beginning renal replacement therapy. Left ventricular hypertrophy (LVH) is associated with an increased mortality rate due to cardiovascular disease, the main cause of death in patients on chronic hemodialysis. In this study, we evaluated 67 chronic hemodialysis patients older than 65 years (33 women and 34 men; mean age, 72.6 years; mean time on chronic hemodialysis, 51.3 months). Several biological and laboratory data were analyzed. The left ventricular mass was calculated using the Penn convention criteria. LVH was observed in 49 patients (73%). These 49 patients were divided into two groups (group 1, concentric hypertrophy, n = 22; and group 2, eccentric hypertrophy, n = 27) and compared with a control group (patients without LVH, n = 18). Group 1 (P = 0.06) and group 2 (P = 0.055) showed higher systolic blood pressures and group 2 showed a lower hematocrit (P = 0.024). The echocardiographic parameters were expectedly different: group 1 had higher posterior left ventricular wall thickness (P = 0.0001), interventricular septum thickness (P = 0.0001), and left ventricular wall relative thickness (P = 0.002), and group 2 had higher left ventricular end-diastolic diameter (P = 0.0001), interventricular septum thickness (P = 0.01), and posterior left ventricular wall thickness (P = 0.023). Using the left ventricular mass index as the dependent variable and the evaluated biological and laboratory data as the independent variables, we found in a stepwise multiple regression model that only systolic blood pressure (t = 3.430; P = 0.0011), age (t = 2.059; P = 0.044), interdialytic weight gain (t = 2.236; P = 0.029), and hematocrit (t = -1.961; P = 0.054) independently influenced the left ventricular mass index (R2 = 0.313; P = 0.0001). Further studies are needed to determine whether reduction of the left ventricular mass index, through control of blood pressure and correction of anemia, will decrease the cardiovascular events in this particular population.     

Essential thrombocythemia following polycythemia vera: an unusual sequence

Myeloproliferative disorders (MPD) are prone to modification and evolution during the progression of the disease. While post-polycythemia myeloid metaplasia and chronic myelogenous leukemia following polycythemia vera have been frequently described, no report is available about the evolution of polycythemia vera into essential thrombocythemia. Our case is probably the first report on this occurrence. In the course of a fortuitous observation of electrocardiographic alterations, a diagnosis of polycythemia vera was ruled out in accordance with polycythemia vera study group criteria. At the time of diagnosis, RBC was 6 x 10(12)/L, WBC 15 x 10(9)/L, Ht 59% and platelets 1000 x 10(9)/L. The patient was treated with phlebotomies and radioactive phosphorus achieving a good remission or the disease. Five years later, platelets rose to over 3300 x 10(9)/L without significant modification or RBC, WBC and Ht. The restaging or the disease was consistent for an essential thrombocythemia. In particular, RBC mass was within normal levels. During the last ten years, the patient has been followed recurrently and the blood picture remained stationary, without an increase in the hematocrit but with a platelet count between 658 and 800 x 10(9)/L. We conclude that this report may complete data concerning the evolution of MPD in others.     

Role of peptide-leukotrienes in bronchial asthma]

In the present study the prognostic value of both DNA ploidy and the proliferative activity of tumour cells were studied in a series of 76 consecutive patients suffering from gastric tumours. DNA ploidy and the proliferative index (as measured by the percentage of S-phase cells) were determined by flow cytometry using fresh tumour specimens. The presence of DNA aneuploid clones by flow cytometry was detected in 62% of the cases (mean DNA index of 1.63 +/- 0.46; range 1.08-2.92), the mean proportion of S-phase cells being of 18.4 +/- 11.5%. In comparison with diploid cases, aneuploid tumours showed a higher proliferative activity (cases with more than 15% S-phase cells: 18.4% versus 6.1%, p = 0.0001) as well as a higher incidence of node involvement (95% versus 68%, p = 0.001). By contrast, no significant differences were detected with respect to sex, age, histologic grade and type, clinical stage, tumour size and the incidence of extranodal involvement. Upon grouping the patients according to the proportion of S-phase cells no significant differences were observed for the clinical and biological parameters explored except for an association between a high percentage of S-phase cells and the presence of DNA aneuploidy (40% versus 96%, p = 0.0001). Regarding survival the presence of DNA aneuploidy was significantly associated with poor outcome as compared to the diploid cases (median of 15 versus 26 months, p = 0.005). By contrast, the proportion of S-phase cells did not predict patients's outcome. Multivariate analysis of prognostic factors showed that the presence of DNA aneuploidy (p = 0.003) together with the histologic type (p = 0.03) and the existence of extranodal metastases (p = 0.05) were the best combination of prognostic factors for survival prediction.     

Serum transferrin receptor in polycythemia

We measured serum transferrin receptor (sTfR) levels in 22 patients with polycythemia vera and in 26 cases of secondary polycythemia. In our study, raised sTfR levels in both polycythemia groups were related to iron deficiency.     

Cardiovascular, renal, and neurohumoral responses to single large-volume paracentesis in patients with cirrhosis and diuretic-resistant ascites

OBJECTIVE: Large volume paracentesis is an effective treatment for refractory ascites, but the need for routine infusion of albumin or other volume expanders remains controversial. The aim of this study was to assess the short term effects of a single 5-L paracentesis without albumin replacement on total central blood volume, systemic and renal hemodynamics, sodium homeostasis, and neurohumoral factors. PATIENTS AND METHODS: Twelve patients with biopsy-proven cirrhosis and tense, diuretic-resistant ascites were studied before and 48 h after a single 5-L paracentesis without albumin infusion. Systemic hemodynamics and total central blood volume were assessed using radionuclide angiography. Glomerular filtration rate and effective renal plasma flow were measured by inulin and para-aminohippurate clearances, respectively. Lithium clearance was used as an index of proximal tubular reabsorption of sodium. In addition, plasma concentrations of neurohumoral factors were determined. RESULTS: Total central blood volume was 2.41 +/- 0.33 L/m2 (mean +/- SEM) before and 2.34 +/- 0.18 L/m2 48 h after large volume paracentesis (p = 0.76). Similarly, no differences were detected in the cardiac index, glomerular filtration rate, effective renal plasma flow, urinary sodium excretion, hematocrit, plasma renin activity, or concentrations of plasma aldosterone, norepinephrine, or atrial natriuretic factor. CONCLUSIONS: A single large volume paracentesis without albumin replacement causes no disturbances in systemic and renal hemodynamics 48 h after the procedure. These results suggest that a single 5-L paracentesis without albumin infusion is a safe and satisfactory short term option for the management of patients with cirrhosis and tense, diuretic-resistant ascites.     

Iron stores and coagulation parameters in patients with hypoxemic polycythemia secondary to chronic obstructive pulmonary disease: the effect of phlebotomies

This study was designed to determine the effects of phlebotomy on iron body contents and coagulation tests of COPD patients with polycythemia secondary to hypoxemia. Seventeen patients with COPD and hematocrits higher than 54 percent (mean Hct: 57 +/- 0.49 percent), who had not received anti-inflammatory or antiplatelet aggregation agents recently. Their mean forced expiratory volume at 1 second (FEV1) was 0.92 +/- 0.11 L. Intervention: Blood work was collected to evaluate the following: serum iron and ferritin levels, total iron binding capacity, transferrin saturation index, fibrinogen plasma levels, activated partial thromboplastin time, platelet count, platelet aggregation measurements, and thromboelastography coagulation parameters. The blood samples were obtained before and about 7 days after the hematocrit correction by 300-400 ml phlebotomies done every other day. The mean number of phlebotomies done for each patient was 4.4. Postphlebotomy iron serum levels decreased from 90.1 +/- 14.8 to 59.7 +/- 9.9 mg/dl and the ferritin serum levels from 133.8 +/- 37.9 to 70.8 +/- 32.7 ng/ml (p < 0.05). Regarding the coagulation studies, there were significant increases in the platelet count, from 227,300 +/- 13,900 to 312,500 +/- 30,200 per mm3, and in the maximum clot amplitude (a) obtained by thromboelastography (from 53.6 +/- 1.4 percent to 60.4 +/- 1.1 percent). The coagulation time (k) of the thromboelastography also decreased significantly, from 7.5 +/- 0.7mm prephlebotomy to 4.5 +/- 0.3mm postphlebotomy. Although the coagulation changes were small amount, the observed significant decrease in iron contents may have clinical implications.     

Blood transfusion and lung function in chronically anemic patients with severe chronic obstructive pulmonary disease

OBJECTIVE: To study in anemic patients with chronic obstructive pulmonary disease (COPD) whether blood transfusion reduces minute ventilation and work of breathing (WOB). DESIGN: We prospectively evaluated the minute ventilation and WOB in 20 anemic adults (hemoglobin of <11 g/dL). Ten patients had severe COPD and ten patients were without lung disease. Measurements were made before and after receiving red blood cell transfusion; post-transfusion measurements were made 24 to 36 hrs after the last transfusion. SETTING: The study was performed in the intensive care unit of a tertiary referral center for home mechanical ventilation and for patients considered difficult to wean from mechanical ventilation. PATIENTS: Twenty clinically stable patients (12 female, eight male) with chronic anemia were studied. Ten patients with COPD (mean forced expiratory volume in 1 sec: 0.55+/-0.1 [SD] L) were compared with ten patients without lung disease. All participants had adequate renal and left ventricular function. INTERVENTIONS: Patients received 1 unit of packed red blood cells for each g/dL that their hemoglobin value was less than an arbitrarily defined target value of 11.0 to 12.0 g/dL. Each unit was transfused over 2 hrs and < or =3 units in total was given. MEASUREMENTS AND MAIN RESULTS: Esophageal pressure was measured from a catheter which was positioned in the middle of the esophagus. Flow was measured using a pneumotachygraph connected to a mouthpiece while a nose clip closed the nostrils during the measurements. From these data, respiratory rate, minute ventilation, and inspiratory resistive WOB were computed. Arterial blood gas values, oxygen saturation, hemoglobin, and hematocrit were also measured, and oxygen content was calculated before and 24 to 36 hrs after transfusion. In patients with COPD, hemoglobin increased from 9.8+/-0.8 to 12.3+/-1.1 g/dL due to a mean transfusion of 2.2+/-0.4 (SD) units of red blood cells. There was a reduction in the mean minute ventilation from 9.9+/-1.0 to 8.2+/-1.2 L/min (p < .0001); correspondingly, WOB decreased from 1.03+/-0.24 to 0.85+/-0.21 WOB/L (p< .0001). The capillary P(CO2) increased from 38.1+/-6.0 to 40.7+/-6.8 torr (5.1+/-0.8 to 5.8+/-0.9 kPa) (p < .05). Similarly, capillary P(O2) changed from 56.9+/-8.9 to 52.8+/-7.0 torr (7.6+/-1.2 to 7.0+/-0.9 kPa) (p < .05). In anemic patients without lung disease, minute ventilation, WOB, and the capillary blood gas values did not change after increase of the hemoglobin by a similar degree. CONCLUSIONS: We conclude that red blood cell transfusion in anemic patients with COPD leads to a significant reduction of both the minute ventilation and the WOB. In these patients, transfusion may be associated with unloading of the respiratory muscles, but it may also result in mild hypoventilation.     

Exercise tolerance in patients with Ebstein's anomaly

OBJECTIVES: The purpose of this study was to identify the determinants of exercise tolerance in patients with Ebstein's anomaly. BACKGROUND: Patients with Ebstein's anomaly of the tricuspid valve may have exercise limitation that improves after surgical repair. METHODS: One hundred seventeen patients performed cycle ergometry for a total of 124 tests (preoperative test in 76 patients, postoperative test in 23, test but no operation in 18, preoperative and postoperative test in 7). Multiple linear regression analysis was used to identify predictors of maximal oxygen uptake, oxygen saturation and heart rate at peak exercise. RESULTS: Age at the time of exercise ranged from 6 to 60 years (median 15). An atrial septal defect was present in 67 patients (88%) preoperatively. Compared with the preoperative group, the postoperative group had significantly higher maximal oxygen uptake (mean [+/- SD] 20.5 +/- 7.4 vs. 25.3 +/- 7.0 ml/kg body weight per min, p = 0.006). Postoperative rest and exercise blood oxygen saturation was higher than that measured preoperatively (p = 0.0001). Six of seven patients tested before and after the operation showed improved exercise tolerance. Preoperatively, major predictors of maximal oxygen uptake were oxygen saturation at rest (p = 0.01) and age (p = 0.0001). Preoperatively, the major predictor of oxygen saturation at peak exercise was rest oxygen saturation (p = 0.0001), and major predictors of peak exercise heart rate were rest heart rate (p = 0.01) and rest oxygen saturation (p = 0.01). In the postoperative group, predictors of maximal oxygen uptake included age at exercise testing, male gender and heart size. CONCLUSIONS: Definitive operation for Ebstein's anomaly results in improved exercise tolerance. Before the operation, rest oxygen saturation is the major predictor of exercise tolerance, oxygen saturation at peak exercise and peak heart rate. Postoperatively, age, gender and heart size influenced maximal oxygen uptake.     

A preliminary comparison of videofluoroscopy of swallow and pulse oximetry in the identification of aspiration in dysphagic patients

BACKGROUND: Sickle cell trait, glucose-6-phosphate dehydrogenase (G6PD) deficiency and alpha-thalassemia trait are common genetic abnormalities among the American Black population. Under oxidative stress, the presence of any of these conditions would predispose the hemoglobin (Hb) to oxidation resulting in accelerated methemoglobin (metHb) formation. It was hypothesized that red cells phenotypic for these genetic variants should have more or different levels of metHb reductase (cytochrome b5 reductase) activity. METHODS: To test this hypothesis, we measured the red cell metHb reductase activity in 558 male subjects (316 Blacks and 242 Whites), by the procedure described by Beutler. All Black patients also had G6PD spot test and Hb electrophoresis. In addition, all patients had a complete blood count (CBC). If the hematocrit was < 35% a reticulocyte count was also done. Patients with corrected reticulocyte (retic count X hematocrit/45) index over 2% were excluded regardless of other findings. RESULTS: The results showed that Blacks had different metHb reductase activity levels than Whites (mean = 3.19 vs 2.89 IU/gHb, respectively with p = 0.03). However, the differences in metHb reductase activities in patients with sickle cell trait, G6PD deficiency, and low MCV < 80 micron3 (presumptively having alpha-thalassemia) in small subgroups did not reach statistical significance (p = 0.2), although, all 3 groups were comprised of small numbers. CONCLUSIONS: It is concluded that American Blacks have significantly different metHb reductase activity. The different metHb reductase activity in Blacks seems to be unrelated to the presence of G6PD deficiency, sickle cell trait, or alpha-thalassemia and it may be the result of genetic polymorphism. However, our study samples do not exactly represent the cross-sections of the Black and White populations. In addition, all patients were male in this study. Therefore, this study should be confirmed using larger and more population-representative samples. The clinical significance of this problem is not clear at this time.     

Acute effects of transjugular intrahepatic portosystemic stent-shunt (TIPSS) procedure on renal blood flow and cardiopulmonary hemodynamics in cirrhosis

OBJECTIVE: An acute increase in portal pressure is associated with an immediate reduction in renal blood flow. It has been suggested that this supports the presence of an hepatorenal reflex. In this study, we used TIPSS placement as a model to investigate the effect of an acute reduction in portal pressure on renal blood flow and cardiopulmonary hemodynamic parameters. METHODS: Eleven cirrhotic patients were studied during elective TIPSS placement for variceal hemorrhage (n = 9) or refractory ascites (n = 2). Unilateral renal blood flow (RBF) was measured before and at 5, 15, 30, 45, and 60 min after shunt insertion. Heart rate (HR), mean arterial pressure (MAP), right atrial pressure (RAP), mean pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and systemic vascular resistance (SVR) were also measured before and 30 min after TIPSS placement. RESULTS: Despite significant increases in CO (p = 0.001), RAP (p < 0.001), PAP (p < 0.001), and PCWP (p = 0.001), and a fall in SVR (p = 0.003), no change was observed in RBF, HR, or MAP after TIPSS placement. The fall in the portoatrial pressure gradient correlated only with the rise in CO (p < 0.05) and the drop in SVR (p < 0.05). CONCLUSION: Despite the fall in portal pressure and the systemic hemodynamic changes caused by TIPSS placement, there is no immediate effect on RBF. Any improvement in renal function after TIPSS procedure does not appear to be due to an acute increase in RBF.     

Reduction of allogeneic blood transfusions after open heart operations by lowering cardiopulmonary bypass prime volume

BACKGROUND: Despite recent advances in blood conservation techniques, up to 30% to 80% of patients undergoing open heart operations require allogeneic blood transfusions. A prospective, randomized study was performed to test the effect of lowering cardiopulmonary bypass prime volume (as an additional component of an integrated blood conservation strategy) on clinical outcome and allogeneic blood transfusion. METHODS: One hundred fourteen patients undergoing open heart operations were randomized to either full prime (FP) volume (1,400 mL of Plasmalyte solution) or reduced prime (RP) volume (600 to 800 mL). The reduction of prime volume was achieved by slowly draining the cardiopulmonary bypass circuit into a cell-saving device before the initiation of bypass. Firm transfusion thresholds were observed. RESULTS: There were no significant differences between the groups with respect to baseline characteristics, body surface area, type and urgency of the procedures, perfusion technique, and hematologic profile. Mortality (FP, 1.7%; RP, 0%; p approximately 1.0) and overall morbidity (FP, 28.1%; RP, 22.8%; p = 0.53) were similar. However, transfusion requirements were significantly lower in the RP group: total donor exposure, 3.8 +/- 10.1 versus 1.0 +/- 2.4 units (p = 0.044); percentage of patients transfused, 54% (n = 31) versus 35% (n = 20) (p = 0.036). Twenty-four-hour chest tube drainage was similar: 455 +/- 223 mL for FP versus 472 +/- 173 mL for RP (p = 0.66). The lowest hematocrit on bypass was significantly higher in the RP group: 29.3% +/- 4% versus 26.3% +/- 5.3% (p = 0.009). CONCLUSIONS: Lowering cardiopulmonary bypass prime volume resulted in a significant decrease in allogeneic blood product use. Because postoperative 24-hour chest tube drainage was similar in both groups, and hematocrit during bypass was higher in the RP group, the reduction in allogeneic blood transfusions appears to be related to a decrease in prime-induced hemodilution. This technique is effective, simple, and safe. It therefore should be strongly considered for patients undergoing operations using normothermic or near-normothermic cardiopulmonary bypass who are at high risk for allogeneic blood transfusion.     

Effects of NMDA antagonism on striatal dopamine release in healthy subjects: application of a novel PET approach

We investigated the in vitro erythroid progenitor growth and the effects of sera on normal-marrow CFU-E (colony-forming units - erythroid) growth in 2 patients with renal failure on regular hemodialysis following a prior history of polycythemia vera (PV). PV was diagnosed 3 and 11 years, respectively, before the development of terminal renal failure. One of the patients had entered a spent phase of PV as characterized by diffuse extensive myelofibrosis and anemia; the other also had mild myelofibrosis. The serum erythropoietin (EPO) levels were low or normal on serial measurements by radioimmunoassay. There was no correlation between the hematocrit values and serum EPO levels. EPO-independent erythroid colonies were present in the cultures of bone marrow and peripheral blood cells from both patients after renal failure in the anemic state. With the addition of various concentrations of EPO, the number of erythroid colonies increased as the concentrations of EPO increased which was in accordance with the clinical observation that 1 patient with postpolycythemic myeloid metaplasia partially responded to recombinant human EPO therapy. In the EPO-dependent CFU-E assay, normal-marrow CFU-E numbers supported by 10% of the patient sera were less than those by normal sera. In the absence of EPO in cultures, no erythropoietic activity was found in the patients' sera. Our study on uremic patients with underlying PV showed that the biologic characteristics of autonomous erythroid progenitor growth for PV persisted during the spent phase and after the development of terminal renal failure with anemia. The erythroid progenitors responded to EPO both in vitro and in vivo. Their sera exhibited an inhibiting effect on the growth of normal-marrow erythroid progenitors.     

Influence of hematocrit on the measurement of lipoproteins demonstrated by the example of lipoprotein(a)

BACKGROUND: The measurement of many parameters of human blood is usually performed in plasma or serum. Since lipoproteins or apolipoproteins, for example, are found almost exclusively in the plasma fraction after low-speed centrifugation, these parameters can be expected to be distributed in a different plasma volume depending on the hematocrit value. Therefore, the measured plasma levels might be relatively too low or too high in comparison to the whole blood concentrations in the case of abnormal hematocrit levels. The aim of our experiments was to evaluate the extent of differences between whole blood and plasma concentrations, taking as an example lipoprotein(a) [Lp(a)] in hemodialysis patients with documented decreased hematocrit values. METHODS: Lp(a) was measured in plasma as well as whole blood of 15 hemodialysis patients with low hematocrit values (0.29 +/- 0.02) in comparison to 11 control subjects (0.45 +/- 0.04). RESULTS: Plasma concentrations were 27% higher in patients than in controls (19.7 vs. 15.5 mg/dl). The relative difference was twice as high (59%) when measured in whole blood (13.5 vs. 8.5 mg/dl). Similar relative differences were observed when whole blood concentrations of 125 hemodialysis patients and 256 controls were calculated with the formula [Lp(a)plasma * (1-hematocrit)]. CONCLUSIONS: Our findings clearly demonstrate that hematocrit is a strong confounding variable of lipoprotein measurement in epidemiological studies when concentrations are measured in plasma, especially in cases of abnormal hematocrit values. Furthermore, studies investigating the longitudinal changes of lipoproteins should consider potential hematocrit changes.