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PubMedDate not supplied

Cardiovascular tissue engineering: constructing living tissue cardiac valves and blood vessels using bone marrow, umbilical cord blood, and peripheral blood cells.

Although atherosclerosis and valvular heart disease are among the leading causes of morbidity and mortality in developed nations, the substitute blood vessels and heart valves currently available all have significant limitations. During the past 10 years, a new field called tissue engineering has emerged, and several research groups are focusing their efforts on constructing living tissue replacement blood vessels and heart valves. In 2001 several exciting developments occurred with the use of progenitor and stem cells. This article introduces the essential concepts of cardiovascular tissue engineering, reviews achievements in the field, discusses the basic developmental biology of heart valves and blood vessels, and summarizes the 2001 research on progenitor and stem cells.

Blood Vessels↗
PubMedDate not supplied

Blood platelets are concentrated near the wall and red blood cells, in the center in flowing blood.

Hematocrit and vessel wall shear rate are important factors in the transport and subsequent adherence of platelets to vessel wall subendothelium. When mass transport theory is applied to platelets in flowing blood, the blood is usually considered to be a fluid with platelet and red cell wall concentrations similar to the average tube concentration. With the laser-Doppler technique, we found how red blood cell ghosts and platelets were distributed radially for various hematocrits and wall shear rates. Red cell ghosts are crowded near the axis of the tube, with a local hematocrit higher than the average tube hematocrit, and they decrease steadily toward the wall. In the absence of ghosts, platelets exhibit the 'tubular pinch' effect (rigid particles crowding at 0.6 x tube radius). In the presence of ghosts, the platelets are expelled toward the wall region. This high concentration at the wall increases with higher average tube hematocrit and wall shear rates. Increasing the average tube platelet concentration 10 times causes the wall concentration to increase only three times. The increase in platelet adherence observed with increasing hematocrit and increasing wall shear rate can be partially ascribed to increased platelet concentration near the wall. The observation that the increased platelet concentration does not fully explain the platelet adherence data suggests that platelet transport may also be enhanced by a shear rate-dependent rotary motion.

Blood Flow Velocity↗
PubMed2002

Laboratory identification of cryoglobulinemia from automated blood cell counts, fresh blood samples, and blood films.

Four cases showing different means to detect cryoglobulins are reported: effects on blood cell counts performed on 2 technologically different automated hematology instruments and microscopic features in fresh blood samples and on May-Grünwald-Giemsa-stained bloodfilms. These cases were chosen for their instructive value in depicting all artifacts associated with cryoglobulins. Laboratory recognition of the cryoglobulins is important to correct factitious results with automated blood cell counters, mainly pseudoleukocytosis and pseudothrombocytosis. Moreover cryoglobulin-induced laboratory artifacts may be the first factor prompting the assessment for cryoglobulinemia and the diagnosis of the underlying cause.

Autoanalysis↗
PubMed2001

Comparative nuclear magnetic resonance studies of water permeability of red blood cells from maternal venous blood and newborn umbilical cord blood.

Comparative morphological and nuclear magnetic resonance (NMR) measurements of the diffusional permeability (Pd) were performed on red blood cells (RBCs) from maternal venous blood and fetal RBCs, isolated from cord blood taken at delivery. Fetal RBC had a diameter of 8.79+/-0.03 microm (mean+/-standard deviation, SD), a volume of 103 microm3 and a surface area of 157 microm2. We report here the first comparative measurements of Pd of maternal and fetal RBCs by using a Mn2+-doping NMR technique. The values of Pd were, in the case of maternal RBC, 3.7 x 10(-3) cm/s at 15 degrees C, 4.1 x 10(-3) cm/s at 10 degrees C, 4.9 x 10(-3) cm/s at 25 degrees C, 5.2 x 10(-3) cm/s at 30 degrees C and 7.2 x 10(-3) cm/s at 37 degrees C. For fetal RBC all corresponding Pd values were almost half, namely 2.0 x 10(-3) cm/s at 15 degrees C, 2.3 x 10(-3) cm/s at 20 degrees C, 2.8 x 10(-3) cm/s at 25 degrees C, 3.4 x 10(-3) cm/s at 30 degrees C and 4.4 x 10(-3) cm/s at 37 degrees C. The decreased Pd values of fetal RBCs were probably due to lower channel-mediated water permeability compared with adult RBCs. The values of the activation energy for water permeability (E(a,d)) were significantly higher for fetal RBCs (27.6+/-5.0 kJ/mol) than for adult RBCs (22.8+/-2.7 kJ/mol). A positive correlation between the Pd values of the two kinds of RBCs was found. This points to the genetic basis for the determination of RBC water permeability.

Cell Size↗
PubMed1985

Changes in blood pressure, heart rate and blood constituents during heat exposure in men with elevated blood pressure.

Although the vascular volume response of hypertensive men during exercise has been rather well characterized, the effect of resting heat exposure in this patient population has not been examined. This was done in the present report in seven men with high blood pressure (BP) (i.e., diastolic pressure greater than 12 kPa (90 mmHg) upon initial interview) and 5 normotensive control subjects. 50 min after each subject had consumed an amount of water equal to 1% of his body weight, he reclined on a cot. 10 min later the subject was carried into an environmental chamber equilibrated at Tdb = 45 degrees C, Twb = 28 degrees C. Free-flowing venous blood samples were obtained from a cubital vein, and BP and heart rate were measured, before the heat exposure and at 15 min intervals during the experiment. Within 30 min systolic, diastolic and mean BP of the high BP subjects had decreased to normal levels; no BP changes were detected in normotensive subjects. Accompanying this depressor response was an exaggerated elevation in plasma glucose concentration. No alterations were found with haematocrit, plasma osmolality or electrolytes, or total protein and albumin. The data suggest that heat exposure may have been more stressful for the subjects with high BP than for their controls. This finding implies that phasic depressor responses may be as important as phasic pressor episodes in the aetiology of established essential hypertension.

Blood Glucose↗
PubMed1979

Comparison of capillary ear blood and arterial blood to validate capillary sampling as an accurate assay of blood gas in swine.

Capillary sampling in swine can be performed as an accurate assay of arterial blood gases. Studies with swine provided results similar to, or slightly more favorable than, those reported for human beings, depending upon which cutaneous technique was used on human beings. On the basis of free flow or arterilization of the cutaneous sample and of the correlation between capillary and arterial pH, CO2 partial pressure (PCO2), and O2 partial pressure (PO2) values, the capillary sampling technique of complete incisement of a 2-mm section from the tip of the warmed porcine ear could be a substitution technique for arterial blood sampling. Free flow with this technique was maximized and high correlation coefficients (r) for pH (r = 0.96), PCO2 (r = 0.82), and PO2 (r = 0.90) capillary-arterial values (n = 37) were obtained.

Animals↗
PubMed1996

Maternal blood C-reactive protein, white blood cell count, and temperature in preterm labor: a comparison with amniotic fluid white blood cell count.

OBJECTIVE: To compare the diagnostic and prognostic performance of maternal blood C-reactive protein, white blood cell count (WBC), and temperature with that of amniotic fluid (AF) WBC in preterm labor. METHODS: One hundred two women with preterm labor and intact membranes were studied. Maternal blood was collected to measure C-reactive protein concentration and WBC, and maternal temperature was also measured. Amniotic fluid obtained by amniocentesis was cultured and WBC determined. Receiver operating characteristic curve, logistic regression, and survival techniques were used for analysis. RESULTS: Patients with acute histologic chorioamnionitis had significantly higher median C-reactive protein concentration, WBC, temperature, and AF WBC than patients without this lesion (P < .05). Receiver operating characteristic curve and survival analysis demonstrated that an elevated C-reactive protein, WBC, or AF WBC was strongly associated with the likelihood of histologic chorioamnionitis, shorter interval to delivery, clinical chorioamnionitis, and neonatal morbidity (P < .05 for each). Of all the tests, AF WBC was the best independent predictor of a positive AF culture (odds ratio [OR] 16.8), interval to delivery (hazard ratio 5.7), clinical chorioamnionitis (OR 15.2), neonatal sepsis (OR 16.8), and significant neonatal complications (OR 7.4), after other confounding variables were adjusted (P < .05 for each). CONCLUSION: An elevated C-reactive protein, WBC, or AF WBC identified patients with intrauterine infection and adverse perinatal outcomes. Amniotic fluid WBC was a better independent predictor of these outcomes than C-reactive protein, WBC, or temperature.

Acute Disease↗
PubMed2004

Efficacy of IgM anti-blood type antibody monitoring by enzyme-linked immunosorbent assay after renal transplantation across the blood barrier: high-dose immunoglobulin administration blocks IgM rather than IgG anti-blood type antibodies.

We used an enzyme linked immunosorbent assay (ELISA) to investigate the presence of subtypes of anti-blood-type antibodies in patients with biopsy-proven humoral rejection after ABO-incompatible renal transplantation. High agglutinin IgG and IgM anti-blood type antibodies from 12 ABO-incompatible recipients with vascular rejection were separately assessed using an ELISA. Patients who exhibited excellent renal function despite high agglutinin titers of anti-blood-type antibodies(n = 8) were also examined. All 12 rejection patients exhibited highly elevated titers of IgG and IgM, while the eight stable patients exhibited only slightly elevated IgG titers, but not IgM. IgG and IgM titers did not change after plasmapheresis and steroid pulse therapy, whereas IVIg treatment significantly blocked both IgG and IgM, with IgM being blocked to a larger extent than IgG. Blocking of IgM seems to play an important role in improving ABO-incompatible grafts.

Antibodies, Anti-Idiotypic↗
PubMed2006

Recommended screening and preventive practices for long-term survivors after hematopoietic cell transplantation: joint recommendations of the European Group for Blood and Marrow Transplantation, Center for International Blood and Marrow Transplant Research, and the American Society for Blood and Marrow Transplantation (EBMT/CIBMTR/ASBMT).

More than 40,000 hematopoietic cell transplants (HCTs) are performed worldwide each year. With improvements in transplant technology, larger numbers of transplant recipients survive free of the disease for which they were transplanted. However, there are late complications that can cause substantial morbidity. Many survivors are no longer under the care of transplant centers and many community health-care providers may be unfamiliar with health matters relevant to HCT. The Center for International Blood and Marrow Transplant Research (CIBMTR), European Group for Blood and Marrow Transplantation (EBMT), and American Society for Blood and Marrow Transplantation (ASBMT) have developed these recommendations to offer care providers suggested screening and prevention practices for autologous and allogeneic HCT survivors.

Delivery of Health Care↗
PubMed2001

[Risky high blood pressure, lipid and blood glucose values. Are blood pressure patients underserved?].

It is now generally accepted that the prognostic relevance of diastolic and systolic blood pressures varies with age. The probable explanation for this is considered to be the age-related hemodynamic changes in central and peripheral arteries. An analysis of 47,000 hypertensives reveals that a therapeutic strategy focused merely on lowering elevated blood pressure is inadequate. Since most hypertensives have multiple risk factors that are readily identifiable and treatable, a multifactorial therapeutic strategy is needed. Accordingly, modern treatment of hypertensives implies a predominant role for risk factor management. A European study on secondary prevention documents an unacceptably high prevalence of unhealthy lifestyles and poorly controlled blood pressure, lipid and glucose levels in patients with clinically diagnosed CHD. It is high time that scientific investigations be carried out to identify the reasons for the inadequate practical implementation of evidence-based preventive and therapeutic measures. It is to be expected that epidemiological investigations will help provide relevant data.

Coronary Disease↗
PubMed1989

Direct cannulation of myocardial blood vessels without interfering with regional blood flow distribution, resting blood flow, or reactive hyperemia.

An in vivo technique of directly cannulating coronary arteries and veins for sampling blood and measuring hemodynamic parameters is described. The cannulation procedure was evaluated for its effects on regional myocardial blood flow (RMBF), transmural RMBF distribution, and reactive hyperemia. In a group of ten dogs, RMBF was measured by using radionuclide microspheres. Values for left anterior descending (LAD) perfusion zone (with catheter) and circumflex (CX) zone (no catheter) did not differ significantly (119 +/- 14 mL/min/100 g v 123 +/- 14 mL/min/100 g, respectively). Likewise, endocardial-to-epicardial RMBF ratio was similar for the two areas (0.99 +/- 0.06 and 1.04 +/- 0.06, respectively). In five dogs, aortic and left ventricular pressures agreed closely with the LAD coronary artery pressure measured with the described catheter system. Arterial flow during rest and reactive hyperemia was measured in five additional dogs by using electromagnetic flow probes placed around the LAD and CX coronary arteries. During both rest and reactive hyperemia, flow was greater in the CX than in the LAD (65.46 +/- 4.12 and 169.62 +/- 9.04 in the CX v 30.24 +/- 0.78 and 102.28 +/- 5.38 in the LAD; P less than 0.05 for both); however, the percentage change from rest to reactive hyperemia was similar for both vessels. In each perfusion zone, flow during rest and reactive hyperemia and the percentage change were not affected by cannulation. The effects of an infusion of adenosine (20 to 40 micrograms/min) into the pulmonary artery with and without the LAD coronary catheters (artery and vein) were tested in six other dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed2003

A comparison of ex vivo expanded DCs derived from cord blood and mobilized adult peripheral blood plastic-adherent mononuclear cells: decreased alloreactivity of cord blood DCs.

BACKGROUND: Cord blood (CB) has been used as an alternative source of transplantable allogeneic stem cells for a variety of malignant and non-malignant diseases. However, we have demonstrated delayed recovery of T- and B-cell function, and T-cell subsets post unrelated CB transplantation (UCBT), and deficiencies of CB mononuclear cells (MNC) in producing cytokines, including G-CSF, GM-CSF, M-CSF, IL-12, and IL-15. In this study we have investigated the ex vivo generation of DC from CB versus mobilized adult peripheral blood (APB) for later use as adoptive cellular immunotherapy. METHODS: CB and APB-adherent MNC were cultured in serum-free media with GM-CSF IL-4, FLT-3 ligand, tumor growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha) for 7 days. Morphology, phenotype, immunohistochemistry, clonogenic activity, and alloreactivity in MLR were evaluated. RESULTS: CB and APB monocyte-derived ex vivo expanded DC expressed similar DC markers CD83 (31.27+ 11.7% versus 34.0+ 5.2%, CB versus APB), CD1a (23.4+ 4.2% versus 27.6+ 6.3%), and CD80 (21.97+ 12.01% versus 27.7+ 5.95). Immunohistochemistry showed that cells with DC morphology expressed CDla but not CD14. Neither FLT-3 ligand nor TGF-fl enhanced DC expansion. Addition of 10% autologous plasma to CB cultures promoted greater cell survival and a 150% increase in CDla + /CD80+ cell recovery. CB DC were 62% as effective stimulators of adult allogeneic T-cels as APB DC (p < .05) in allogeneic MLR. DISCUSSION: While phenotypically similar, CB and APB DC have differential potency in allogeneic MLR, which may account for the difference in GvHD and infection incidence and severity between UCBT and allogeneic stem cell transplantation, and may require a different approach for adoptive cellular immunotherapy. The mechanism(s) associated with these differences require further elucidation.

Adult↗
PubMed1992

Effect of home blood pressure and gender on estimates of the familial aggregation of blood pressure. The Tecumseh Blood Pressure Study.

Blood pressure (BP) readings from a single clinic visit are often used in population studies investigating the genetic basis of BP. We examined first-degree relatives in the Tecumseh Blood Pressure study to compare heritability estimates of BP readings obtained in the clinic-office setting (the average of two seated readings) with self-reported home BP readings (the average of 14 readings) taken over a 1-week period. The hypothesis tested was that repeated BP readings obtained in the home over the 1-week period would have fewer artifacts (i.e., environmentally induced variability in BP) and thus would better estimate the true "basal" BP that, in turn, would improve heritability estimates. We and others assume that the true basal BP level is heritable. We therefore expected that this "true" BP, by reducing BP variability of offspring, would show a stronger between-sibling correlation and that it would correlate better to parental BP as measured in a clinic setting. Correlation coefficients were calculated between siblings in the present Tecumseh study using self-reported home BP and clinic BP readings. Among 380 siblings (average age, 31.4 years), correlation coefficients for the home readings were of the same magnitude as for office readings (home, r = 0.23, p less than 0.01; office, r = 0.24, p less than 0.01). When offspring clinic BP readings were compared with archived BP data on parents, the correlation between offspring clinic and parental clinic BP readings was stronger (r = 0.24, p less than 0.05) than the correlation of offspring home BP readings to parental clinic BP readings (r = 0.17, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Differences between peripheral blood and cord blood in the kinetics of lineage-restricted hematopoietic cells: implications for delayed platelet recovery following cord blood transplantation.

Cord blood (CB) cells are a useful source of hematopoietic cells for transplantation. The hematopoietic activities of CB cells are different from those of bone marrow and peripheral blood (PB) cells. Platelet recovery is significantly slower after transplantation with CB cells than with cells from other sources. However, the cellular mechanisms underlying these differences have not been elucidated. We compared the surface marker expression profiles of PB and CB hematopoietic cells. We focused on two surface markers of hematopoietic cell immaturity, i.e., CD34 and AC133. In addition to differences in surface marker expression, the PB and CB cells showed nonidentical differentiation pathways from AC133(+)CD34(+) (immature) hematopoietic cells to terminally differentiated cells. The majority of the AC133(+)CD34(+) PB cells initially lost AC133 expression and eventually became AC133(-)CD34(-) cells. In contrast, the AC133(+)CD34(+) CB cells did not go through the intermediate AC133(-)CD34(+) stage and lost both markers simultaneously. Meanwhile, the vast majority of megakaryocyte progenitors were of the AC133(-)CD34(+) phenotype. We conclude that the delayed recovery of platelets after CB transplantation is due to both subpopulation distribution and the process of differentiation from AC133(+)CD34(+) cells.

AC133 Antigen↗
PubMed1989

The effects of prolonged ketamine-xylazine intravenous infusion on arterial blood pH, blood gases, mean arterial blood pressure, heart and respiratory rates, rectal temperature and reflexes in the rabbit.

The prolonged and safe maintenance of general anesthesia in rabbits with commonly used injectable agents is difficult. Protracted, stable anesthesia with short recovery time has been described in humans using continuous intravenous infusion of ketamine with or without sedatives, muscle relaxants and paralytics. This study evaluated the anesthetic plane achieved and respiratory and cardiovascular effects produced with a ketamine-xylazine intravenous infusion in New Zealand White rabbits. Ten female rabbits were anesthetized with intramuscularly administered ketamine hydrochloride (35 mg/kg) and xylazine hydrochloride (5 mg/kg) after the preanesthetic, baseline measurements of arterial blood pO2, pCO2 and pH and heart and respiratory rates were recorded. The above parameters as well as mean arterial blood pressure, righting, palpebral, pedal, and jaw reflexes were monitored ten minutes after the intramuscularly administered dosage and throughout 4 hours of infusion. Results showed moderate hypotension (21.2% deviation from normal, p less than 0.008) and profound hypoxemia (45% deviation from baseline, p less than 0.001) 10 minutes after the intramuscularly administered induction dosage. Then, the 4 hour infusion of ketamine (1 mg/minute) and xylazine (0.1 mg/minute) was started. Hypotension progressed (49.1% deviation from normal, p less than 0.008), but hypoxemia and hypercarbemia gradually improved with no resultant change (p greater than 0.1) in arterial pH. There was no significant change (p greater than 0.1) in respiratory rate but varying qualities of respiration were observed. Both mean arterial pO2 and pCO2 values returned to baseline within 20 minutes after completion of infusion. Heart rate and rectal temperature remained stable during the trial. The righting reflex was abolished in all rabbits throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1993

[Evaluation of home blood pressure measurement by a correlation study between home blood pressure and ambulatory blood pressure].

To evaluate the self-measurement of blood pressure at home, a comparative study was performed among home (Home BP), ambulatory (24-hour BP) and office blood pressure in essential hypertensive patients. In all patients, Home BP was self measured by themselves twice a day for a month. 24-hour BP was measured once during the period of self-Home BP measurement. Office BP was measured twice a month. The average of Office BP (147/92 mmHg) and Home BP (145/89 mmHg) were higher than the average of 24 hour BP (131/82 mg). For systolic BP, about two weeks self-measurement of BP at home just after waking elicited a very high correlation between home and average 24-hour BP (r = 0.82), whereas for diastolic BP the r value was moderate (r = 0.61). In patients (n = 22) treated with antihypertensives, furthermore, the correlation coefficient between home and 24-hour BP for systolic BP reached 0.89, which is higher than in all patients (n = 28). The average value of BP measured just after waking at home elicited a higher correlation with the average value of 24-hour BP compared with that measured before going to bed. The results suggest that in essential hypertensive patients who are treated with antihypertensives, to measure BP just after waking for about two weeks at home could help clinicians to evaluate and predict the value of average 24-hour BP.

Adult↗
PubMed1977

Blood pressure in a high school population. I. Standards for blood pressure and the relation of age, sex, weight, height, and race to blood pressure in children 14 to 18 years of age.

This is a report on the initial from an ongoing study of blood pressure in ninth to twelfth grade students in the St. Louis metropolitan area. The purpose was to establish standards, to determine the incidence of hypertension, and to examine the relationship of blood pressure to age, weight, height, sex, and race. Subjects with persistent hypertension were to be investigated and checked annually as long as they were in high school. Students in the ninth grade at the beginning of the project were to be screened each year for four years.

Adolescent↗
PubMedDate not supplied

[Blood urea concentration, a parameter for the assessment of protein metabolism in pregnant sows. 2. Relations between blood urea concentration and urine nitrogen excretion as well as estimation of urine nitrogen excretion from the blood urea concentration].

The influence of supplementing the ration with the limiting amino acid lysine on N-excretion in urine and the urea concentration in the blood (UCB) is investigated in an experiment with pregnant young sows. In contrast or the basic ration the most satisfactory N-utilisation reflects itself after a lysine intake of 8.2 g/animal and day during the early phase of gestation and 8.6 g during the last phase of gestation both in a diminished N-excretion in urine and a lower UCB. The following correlation coefficients were calculated for the relation between UCB an N-excretion in urine: early phase of gestation: 0.177 (n = 37); last phase of gestation. 0.431 (n = 30); gestation as a whole: 0.416 (n = 67). In a second experiment methionine supplementation in the feeding of a ration with a deficit of sulphur-containing amino acids led to a significant decrease of N-excretion in urine (alpha = 5%). While UCB also significantly decreased 5 hours after feeding, UCB virtually did not react to a changed level of amino acid intake when the blood sample was taken before feeding. In a third experiment, in which 49 g N/animal and day were taken in, differences regarding N-excretion in urine and UCB between pregnant and non-pregnant animals could not be established. When the results published in the first communication (Herrmann and Schneider, 1981) are included, the following correlation coefficients for the relation between N-excretion in urine and UCB are the result: 0.716 (n = 182) for sampling before feeding and 0.808 (n = 133) for sampling 5 hours after feeding. The confidence range of the estimated function y = -2.97 + 1.233 chi for the relation between N-excretion in urine (y; g/animal and day) and UCB 5 hours after feeding (chi; mg/100 ml serum) as well as the variability values do not make it possible to estimate N-excretion in urine from UCB with satisfactory accuracy.

Animals↗