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At least 577 records · Page 32Linked to original sources
PubMed1997

Prevalence of transmissible blood infections among blood donors at the University of Maiducuri Teaching Hospital, Maiduguri, Nigeria.

Before the advent of the Acquired Immune Deficiency Syndrome (AIDS), many countries of the world transfused blood without seriously considering the potential risks of transmission of infectious agents. Even after it was shown that the Human Immunodeficiency virus(HIV) could be transmitted through blood and blood products, many hospitals and clinics in Nigeria still continue to transfuse unscreened blood. This study was therefore initiated to highlight the risks of transmitting infectious agents through blood transfusion and the category of infectious agents which could be transfused in blood in this area. A total of 364 healthy blood donors were counselled, bled and screened for HIV-1, HIV-2, HBsAg, Treponema pallidum, Plasmodium falciparum and microfilaria. The results show that the three most common infections transmissible through blood transfusion are Hepatitis B(14.9%), HIV-1 (5.8%) and P.falciparum (4.1%). Thirteen of the 364 blood donors (3.6%) and antibodies to T. pallidum. There were no donors with HIV-2 or filarial infection. Infection of donors by hepatitis B virus (HBV), T. pallidum and HIV-1 was not significant dependent on promiscuity, polygamy, previous blood transfusion or local surgery. However, there was a significant difference between donors with no risk factors and those with risk factors with regard to seroprevalence to HBV, T. pallidum and HIV-1 (p = 0.0053). The results confirm that transfusion of unscreened blood carries severe risks of transmitting serious infectious agents and that is a need to enforce laws for transfusing blood in Nigeria. Meanwhile, in the absence of screening facilities, proper counselling of blood donors in order to ascertain their risk behaviour should be used to select donors and reduce this risk.

Adult↗
PubMedDate not supplied

Lead levels in blood bank blood.

Although blood bank blood is usually screened for dangerous pathogens, the presence of toxic metals in blood has received little attention. Population blood lead levels have been declining in the United States, but occasional high outliers in blood lead concentration can be found--even when mean levels of blood lead are low. We sampled 999 consecutive blood bank bags from the King/Drew Medical Center, used between December 1999 and February 2000. The geometric mean blood lead level was 1.0 microg/dl (0.048 micromol/l), but 0.5% of the samples had lead levels that exceeded 10 microg/dl, and 2 samples had lead levels that exceeded 30 microg/dl. The 2 samples with the highest lead levels could have presented an additional risk to infants if they were used for blood replacement. Therefore, even in countries with generally low population blood lead levels, blood bank blood should be screened for lead concentration prior to use with infants.

Blood Banks↗
PubMed1992

Discrepancies in recording systolic blood pressure of elderly persons by ambulatory blood pressure monitor.

Agreements between auscultatory blood pressure measurements and recordings of the Suntech Accutracker II ambulatory blood pressure monitor (ABPM) were examined in 103 participants ages 23 through 91 to estimate influence of age on accuracy of automated recordings. Simultaneous auscultation by two technicians and recording by the ABPM were compared. Technicians demonstrated close agreement in auscultation of blood pressure. Mean systolic blood pressure measured by ABPM was 5.6 mm Hg lower and mean ABPM diastolic blood pressure was 6.3 mm Hg lower than average auscultatory blood pressure measured by technicians (P less than .0001). Discrepancies in systolic blood pressure measurements between technicians and ABPM were associated with age and systolic blood pressure. The age effect, controlled for gender and race, was a 0.15 mm Hg increase in systolic blood pressure discrepancy per year of age. Discrepancies in diastolic blood pressure measurements were associated with race but not with age or body size measurements. Automated recordings of blood pressure by this ABPM may have systematic bias compared to auscultation which exceeds current standards for ABPM instrumentation. For systolic blood pressure, this bias increases with age and may affect interpretation of ABPM recordings in elderly persons.

Adult↗
PubMed2005

Correlation between finger blood flow and changes in optic nerve head blood flow following therapeutic intraocular pressure reduction.

PURPOSE: To correlate finger blood flow and changes in optic nerve head (ONH) blood flow following therapeutic intraocular pressure (IOP) reduction in open-angle glaucoma (OAG) and ocular hypertension (OHT). METHODS: Seventeen open-angle glaucoma patients and nineteen ocular hypertension patients underwent therapeutic IOP reduction followed by a minimum of 4 weeks of follow-up. Optic nerve head blood flow measurements were obtained by scanning laser Doppler flowmetry using full-field perfusion image analysis. Finger blood flow was measured using the Transonic laser Doppler Flowmeter. Finger blood flow was measured at baseline, after immersion in warm water (40 degrees C) for 2 minutes (Flow Max), and after immersion in cold water (4 degrees C) for 10 seconds (Flow Min). Patients were identified as vasospastic if their Flow Max/Flow Min >7. Statistical comparisons were performed using two-tailed distribution paired T-test and Pearson's correlation factor. RESULTS: For similar mean percentage intraocular pressure reduction, vasospastic patients had greater improvements in rim blood flow than did non-vasospastic patients [+35% versus +13%] (P = 0.01). While there was no difference in rim blood flow changes in the vasospastic versus the non-vasospastic OAG group, the vasospastic ocular hypertension group showed 18% increase in rim blood flow whereas the non-vasospastic ocular hypertension group showed an 8% decrease. A significant negative correlation was also found in the open-angle glaucoma group between rim blood flow change and Flow Max (-0.681, P = 0.003). In contrast, no such correlation was found in the ocular hypertension group (+0.144, P = 0.556). CONCLUSION: OAG patients had a significant negative correlation between changes in rim blood flow and maximum finger Doppler flow. Among ocular hypertension patients, increased rim blood flow was only found in the vasospastic group, though this increase was not statistically significant. These results suggest that open-angle glaucoma and ocular hypertension patients with the most severe vasospastic disease may show the greatest improvements in rim blood flow after sustained intraocular pressure reduction.

Aged↗
PubMed1975

Effects of decreasing arterial blood pressure on cerebral blood flow in the baboon. Influence of the sympathetic nervous system.

The influence of the sympathetic nervous system on the cerebral circulatory response to graded reductions in mean arterial blood pressure was studied in anesthetized baboons. Cerebral blood flow was measured by the 133Xe clearance method, and arterial blood pressure was decreased by controlled hemorrhage. In normal baboons, the constancy of cerebral blood flow was maintained until mean arterial blood pressure was approximately 65% of the base-line value; thereafter, cerebral blood flow decreased when arterial blood pressure was reduced. Superior cervical sympathectomy of 2-3 weeks duration did not affect the normal response. In contrast, both acute surgical sympathectomy (cervical trunk division) and alpha-receptor blockade (1.5 mg/kg of phenoxybenzamine) enhanced the maintenance of cerebral blood flow in the face of hemorrhagic hypotension in that cerebral blood flow did not decrease until mean arterial blood pressure was approximately 35% of the base-line value. The results indicate that the sympathetic nervous system is not involved in the maintenance of cerebral blood flow in the face of a fall in arterial blood pressure. Indeed, the implication is that the sympathicoadrenal discharge accompanying hemorrhagic hypotension is detrimental to, rather than responsible for, cerebral autoregulation.

Adrenergic alpha-Antagonists↗
PubMed2005

Assessment of the effect of dilution of blood samples with sodium heparin on blood gas, electrolyte, and lactate measurements in dogs.

OBJECTIVE: To evaluate the effect of dilution of blood samples with sodium heparin on blood gas, electrolyte, and lactate measurements in dogs. Sample Population-Venous blood samples collected from 6 adult dogs of various breeds. PROCEDURE: Syringes were prepared with anticoagulant via 1 of 4 techniques, and the residual volume of liquid heparin in each type of prepared syringe was determined. Blood gas values and other selected clinicopathologic variables were measured in whole blood samples after collection (baseline) and after aliquots of the samples were diluted with heparin via 1 of the 4 manual syringe techniques. By use of a tonometer, whole blood samples were adjusted to 1 of 3 oxygen concentrations (40, 100, or 600 mm Hg) and the PO2 values were measured at baseline and subsequent to the 4 heparin dilutions. RESULTS: The 4 syringe techniques resulted in 3.9%, 9.4%, 18.8%, and 34.1% dilutions of a 1-mL blood sample. Compared with baseline values, dilution of blood samples with liquid heparin significantly changed the measured values of PCO2, PO2, and base deficit and concentrations of electrolytes and lactate. Of the variables assessed, measurement of ionized calcium concentration in blood was most affected by heparin dilution. CONCLUSIONS AND CLINICAL RELEVANCE: These findings in dogs indicate that dilution of blood samples with heparin can be a source of preanalytical error in blood gas, electrolyte, and lactate measurements. Limiting dilution of blood samples with heparin to < 4% by volume via an evacuation technique of syringe heparinization is recommended.

Animals↗
PubMed2003

Cord blood collection for the National Cord Blood Bank in Thailand.

Umbilical cord blood is an effective alternative source of hematopoietic stem cells transplantation in children and adolescents. However, the efficacy and safety of cord blood transplantation correlates with the quantity and quality of cord blood. To evaluate the collection systems and processing of cord blood donations, a pilot research program to optimize recruitment, collection and processing of cord blood donations was developed. The present results showed that the quality of the cord blood (volume, total white blood cells (WBC) count, CD34+ and sterility control) collected was satisfactory and discard rate of collecting units (24.2%) were comparable with data reported from other cord blood banks. To find the optimal mode of collection, comparison of 3 cord blood collection methods (Method 1 = Hanging method after delivering the placenta, Method 2 = Aspiration from in utero placenta, Method 3 = Aspiration from in utero placenta and Syringe-assisted aspiration) using the closed system showed that method 3 was the best method but it required more trained personnel and involved a complicated procedure. The National Cord Blood Bank started its activity in 2002 after several years of pre-clinical studies. To date, a number of transplants using cord blood from related and unrelated cord blood (first report in Thailand) donors have been successfully performed.

Adolescent↗
PubMed1978

Leg blood flow and central circulation at varying blood volumes. An intra-operative study of nine patients undergoing a femoro-popliteal vein bypass graft.

Common femoral arterial and bypass blood flows, cardiac output, brachial arterial and central pressures were measured in nine patients undergoing a femoro-popliteal vein bypass graft for intermittent claudication. The measurements were performed during neuroleptanesthesia before the operation, after the operation before blood substitution and then after transfusions of 450,900 and 1350 ml of blood. The leg blood flows were measured before and during local vasodilatation induced by intra-arterial injection of bamethane (Vasculat). The bypass flow was only 55 ml/min before blood substitution but was increased to 215 ml/min after the blood transfusions. The corresponding values for the common femoral artery were 100 ml/min and 430 ml/min, respectively. The maximal flow in the bypass vein during vasodilatation with bamethane (Vasculat) was 145 ml/min before blood substitution and 270 ml/min after the transfusions. This implies that the flow response to vasodilatation was more pronounced before than after blood substitution. The leg blood flow increased proportionally more than cardiac output on blood substitution. It is concluded that leg blood flow is very sensitive to hypovolemia and can be increased considerably by adequate blood substitution. The flow response to local vasodilatation is proportionally higher during hypovolemia.

Adult↗
PubMed1995

Impact of autologous blood predonation on a comprehensive blood conservation program.

Preoperative autologous donation has been shown to be a highly effective measure in reducing homologous blood use in cardiac operations. The aim of our study was to verify the effectiveness of this procedure and to see whether it is compatible with a comprehensive blood conservation program. Three hundred forty-eight patients (group 1) donated an average of 657 +/- 199 mL of blood before open heart operation, whereas 344 patients (group 2) without autologous predonation were used as a control. The two groups were compared with regard to homologous blood use and the possibility of applying other blood conservation measures. Homologous transfusion rate in group 1 was 12.6%, whereas in group 2 it was 46% (p < 0.001). Patients with three units of predonated autologous blood had a transfusion rate of 0.8% (p < 0.001 compared with group 2). In group 1, acute normovolemic hemodilution was accomplished in a lower number of patients and with a lower average withdrawal (338 +/- 102 versus 403 +/- 145 mL; p < 0.001). Other blood conservation measures such as the return of mediastinal drainage and use of residual blood of extracorporeal circulation were applied with similar results in both groups. In our experience, preoperative autologous donation was compatible with the application of other blood conservation measures, but acute normovolemic hemodilution was achieved in a lower number of patients. Preoperative autologous donation proved to be a highly effective method for reducing banked blood use and therefore homologous blood exposure during and after cardiac operations.

Adult↗
PubMed1996

Ketone body ratios of the superior and inferior vena cava and of pulmonary arterial blood compared to that of arterial blood: central venous ketone body ratio as a substitute for the arterial ketone body ratio.

To investigate the ketone body ratio (acetoacetate/3-hydroxybutyrate) of central venous blood compared to that of peripheral arterial blood, the acetoacetate and 3-hydroxybutyrate concentrations in paired peripheral arterial and central venous or pulmonary arterial blood were measured. The ketone body concentrations in superior and inferior vena cava blood were significantly (P < 0.0001) lower than those in peripheral arterial blood, whereas those in pulmonary arterial blood were almost the same as those in peripheral arterial blood. These results indicate that ketone bodies were metabolized in the muscles, which reduced their levels in vena cava blood, but ketone bodies newly produced by the liver were transported to the right side of the heart via the hepatic vein, giving concentrations in pulmonary arterial blood that were almost the same as those in peripheral arterial blood. On the other hand, the correlation coefficients (r2) of the arterial blood ketone body ratio to the ratio of superior and inferior vena cava and pulmonary arterial blood were 0.897, 0.767 and 0.882, respectively. The ratios of central venous ketone body ratio/arterial blood ketone body ratio were 0.89 +/- 0.15 in the superior vena cava, 0.64 +/- 0.18 in the inferior vena cava and 1.01 +/- 0.15 in the pulmonary artery.

3-Hydroxybutyric Acid↗
PubMed2000

Quantitative measurement of local cerebral blood flow in the anesthetized mouse using intraperitoneal [14C]iodoantipyrine injection and final arterial heart blood sampling.

Autoradiographic measurement of local cerebral blood flow (CBF) with [14C]iodoantipyrine (IAP) is limited in mice by the difficulty in cannulating vessels and the blood loss for repeated blood sampling. The authors modified and validated the method to measure local CBF with [14C]IAP in mice by combining intraperitoneal tracer application with a single blood sampling from the heart at the end of the experiment. Experiments were carried out in male SV129 mice under halothane anesthesia. After intraperitoneal administration of 15 microCi [14C]IAP, arterial blood samples were collected repeatedly and anesthetized animals were immersed in liquid nitrogen. In addition, frozen blood from the heart was sampled to obtain the final blood [14C]radioactivity. Correlation analysis between the sampling time and [14C]radioactivity of the arterial blood revealed a highly significant linear relationship (P < 0.001, r = 0.978) and a lag time of the [14C]tracer in arterial blood of 3.3 +/- 0.6 seconds. [14C]radioactivity of the final arterial blood sample (444 +/- 264 nCi/mL) was almost equal to that of the heart blood (454 +/- 242 nCi/mL), and the absolute difference in each animal was 3.3 +/- 4.2% (mean +/- SD). The convolution integrals for the CBF calculation were determined either by integrating the radioactivity of individual arterial blood samples or by assuming a linear rise from [14C]tracer lag time after intraperitoneal [14C]IAP injection to the value measured in the blood sample from the frozen heart. Regional flow values calculated by the two methods differed by less than 11% (not significant). This method allows the quantitative measurement of local CBF in anesthetized mice without any vessel catheterization and will make mutant mice a more powerful tool to elucidate the molecular mechanisms of brain injuries by combining flow studies with molecular-biological methods.

Animals↗
PubMed2000

Elevated blood lead levels and blood lead screening among US children aged one to five years: 1988-1994.

OBJECTIVES: To estimate the proportion of children 1 to 5 years of age who received blood lead testing during 1988-1994 and to assess whether predictors of testing coincided with predictors of elevated blood lead levels. DESIGN: Cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey. Participants. US children 1 to 5 years of age. Outcome Measures. Prevalence of blood lead testing and elevated blood lead levels among children 1 to 5 years of age and odds ratios for factors predicting blood lead testing and elevated blood lead levels. RESULTS: Overall, 6.3% had elevated blood lead levels and 10.2% had undergone previous blood lead tests. Being of minority race/ethnicity, living in an older home, residing in the Northeast or Midwest regions of the United States, being on Medicaid, having a head of household with <12 years of education, and having a history of anemia were significant factors in both models. Additional independent risk factors for an elevated blood lead level included being sampled in phase 1 of the survey, being 1 to 2 years of age, not having a regular doctor, and being sampled during the summer months. Additional independent correlates of a previous blood lead test included having moved less than twice in one's lifetime, having a female head of household, and having parents whose home language was English. Of an estimated 564 000 children 1 to 5 years of age who had elevated blood lead levels and no previous screening test in 1993, 62% were receiving Medicaid, 40% lived in homes built before 1946, and 34% were black, non-Hispanic. CONCLUSIONS: Lead screening was more frequent among children with risk factors for lead exposure. However, among children with elevated blood lead levels, only one third had been tested previously. In 1993 an estimated 564 000 children 1 to 5 years of age had elevated blood lead levels but were never screened. Physicians should screen Medicaid-eligible children and should follow state or local health department recommendations about identifying and screening other at-risk children. In areas where no health department guidelines exist, physicians should screen all children or screen based on known risk factors.

Black or African American↗
PubMed2000

On-line dynamic measurement of blood viscosity, hematocrit and change of blood volume.

OBJECTIVE: To develop an on-line system for the measurement of blood viscosity and hematocrit. The dynamic changes of the macrovascular blood volumes, microvascular blood volumes and the total blood volume were observed by means of calculating from the testing result. METHODS: Applying traditional viscosity measurement principle and specific wavelength optic density measurement method, an on-line system for the measurement of blood viscosity and hematocrit was developed, and the A/D multifunctional board and the testing circuit were designed by ourselves. The system was validated by experiments both in vitro and in vivo. Therapeutic effects of hypertonic saline dextran solution (HSD) and Lactatic Ringer's solution at the early stage after burn-blast combined injury were compared by this method. RESULTS: The results showed that the system has attained the goal of the design. The changes of the blood viscosity and hematocrit could be detected effectively and continuously. The changes of macrovascular, microvascular and total blood volume could be calculated approximately. CONCLUSIONS: The system and the method can continuously on-line test the blood viscosity and hematocrit, and reveal the change and distribution of blood volumes more accurately and clearly in the therapy process by estimating changes of the macrovascular, microvascular and total blood volumes, respectively. It has confirmed that HSD treatment could increase blood pressure and attenuate tissue edema by significantly increasing total blood volume, improving macrocirculatory and microcirculatory blood volumes. This study suggested that it could be desirable to develop an experiment technique based on the method mentioned above.

Journal Article↗
PubMed1998

Blood cell damage after in vitro irradiation of fresh whole blood with 630 nm laser light.

A study on blood cell damage after irradiation of fresh whole blood with 630 nm laser light was carried out in vitro. Various fluence rates of laser light were used with and without cooling of blood. Damage to the blood was assessed by blood cell counts, osmotic fragility measurements and examination of blood films. Exposure of a 1 mm blood layer to 630 nm laser light without cooling led to changes in blood counts first detected at fluence rates of 130 mW/cm2. Changes in osmotic fragility first became evident at 210 mW/cm2. Increasing cell damage with increasing fluence rates was evident in blood films. Using the cooling device changes in whole blood after irradiation first occurred at a fluence rate of 293 mW/cm2. Measurement of the fluence rates at which cell damage begins is important in laser induced fluorescence diagnostics and photodynamic therapy applications in blood or blood products using photosensitizers.

Adult↗
PubMed1999

[Intraoperative blood requirements and allogeneic blood transfusion in cardioanesthesia. Data analysis of 7729 patients in 12 cardiac surgical clinics].

UNLABELLED: Allogeneic blood requirements in cardiac surgery shows a wide variation even for comparable procedures. The aim of the present study was to compare the intraoperative allogeneic blood requirement in defined cardiac operations among 12 cardiac centers in Germany. METHOD: A data set with 25 variables concerning the intraoperative course in adult cardiac patients with myocardial revascularization, valve replacement (aortic or/and mitral valve) or combined procedures was distributed to the participating centers. The data of all patients between January 1th 1998 and June 30th 1998 were included. Besides demographic data, the intraoperative transfusion of allogeneic and autologous blood, fresh frozen plasma and the concomitant hematocrit values were registered. Data were analyzed for all centers and separated for each center. RESULTS: The data of 7,729 patients were analyzed. The intraoperative allogeneic blood requirement was 0.6 +/- 1.3 units for all patients. It varied among the centers from 0.25 +/- 0.6 units to 0.97 +/- 1.6 units (P < 0.05). The percentage of patients receiving allogeneic blood was 27% and differed among the centers from 17% to 35%. Female patients were transfused in 53% (36-39%) compared to male patients with 16% (9-20%) (P < 0.05). The rate of autologous blood predonation varied from 0.5% to 23%. Patients without autologous predonation were transfused in 28% compared to 4% in patients with predonation (P < 0.05). In patients with autologous predonation the intraoperative transfusion of allogeneic blood was significantly reduced (0.1 +/- 0.39 vs 0.6 +/- 1.4 units, P < 0.05). However, some centers with a high percentage of autologous predonation also demonstrated a high rate of perioperative allogeneic transfusion. CONCLUSION: The incidence of allogeneic blood transfusion in cardiac surgery depends on the institution and not on the surgical procedure. A common threshold value of hemoglobin for the transfusion of blood trigger even for comparable procedures could not be detected among the centers. Especially in female patients, there was a wide variation in allogeneic blood transfusion. Autologous blood predonation reduces blood requirement significantly, however, it is practiced with variing intensity. The data set did not include information about transfusion regimen in the postoperative period, thus, these data do not allow to draw conclusions for the whole perioperative period.

Adult↗
PubMed1997

Surfactant nebulisation prevents the adverse effects of surfactant therapy on blood pressure and cerebral blood flow in rabbits with severe respiratory failure.

OBJECTIVE: Surfactant replacement therapy for the neonatal respiratory distress syndrome has shown beneficial effects on lung function and survival. Recently, rapid fluctuations of haemodynamics and cerebral perfusion following surfactant instillation have been described and an association with the development of intraventricular haemorrhage has been proposed. Therefore, alternative methods of surfactant therapy that reduce the effects on cerebral perfusion have to be explored. Does instillation of surfactant influence blood pressure and cerebral blood flow in rabbits with severe respiratory failure? Can nebulisation of surfactant prevent these adverse effects on blood pressure and cerebral blood flow? INTERVENTIONS: Surfactant (Alveofact, 100 mg/kg body weight) was nebulised using the MiniNEB nebuliser, or instilled, in 12 rabbits with severe respiratory failure induced by lung lavage. Assessed were blood gasses, mean arterial blood pressure (MABP) and cerebral blood flow over the left carotid artery, using ultrasonic transit-time flow probes. RESULTS: Partial pressure of oxygen in arterial blood increased quickly after instillation, from 8.7 +/- 1.3 to 24.9 +/- 6.4 kPa after 15 min, and increased gradually during nebulisation from 8.0 +/- 0.5 to 24.5 +/- 4.6 after 120 min. After instillation, MABP decreased 22 +/- 5% (in 8 min) and cerebral blood flow dropped even more: 64 +/- 9% within 8 min. During nebulisation, MABP did not change significantly and cerebral blood flow decreased gradually, 31 +/- 14% over 90 min. CONCLUSIONS: Surfactant instillation was followed by a rapid decrease in MABP and an even more pronounced drop in cerebral blood flow, while during nebulisation MABP did not change and cerebral blood flow decreased less and more gradually.

Animals↗
PubMed2001

Prevalence of blood-borne viral infections (cytomegalovirus, human herpesvirus-6, human herpesvirus-7, human herpesvirus-8, human T-cell lymphotropic virus-I/II, human retrovirus-5) among blood donors in Latvia.

The identification of blood-borne viral infections is important in transfusion medicine. The aim of this study was to evaluate the prevalence of human herpesvirus (HHV) [cytomegalovirus (CMV), HHV-6, HHV-7 HHV-8] and human retrovirus (HRV) (human T-cell lymphotropic virus (HTLV)-I/II, HRV-5) infections among apparently healthy Latvian blood donors. DNA extracted from peripheral blood leukocytes (PBL) of 150 individuals was tested for herpesviruses by sensitive polymerase chain reaction (PCR) technique. None of the blood donors was positive for HHV-8 infection, while the incidence of latent beta-herpesvirus infections was high: single infection by CMV, HHV-6, and HHV-7 was detected in 2.6%, 8.0%, and 43.3% of blood donors, respectively. Simultaneous dual and triple infections of these viruses were observed in 28.0% and 4.7% of individuals, respectively. Active infection by CMV and HHV-6 was not found, but HHV-7 DNA was present in plasma of 10.6% of the blood donors. While all blood donors were HTLV-II and HRV-5 negative, 4.6% of HTLV-I seronegative blood donors were positive for the HTLV-I tax gene, although none of them harbored sequences for structural genes of the provirus. Based on our results, we conclude that monitoring of beta-herpesvirus infections in blood donors can be important in cases of transfusions to immunocompromised persons. HHV-8, as well as the retroviruses HTLV-II and HRV-5, were not found in blood of Latvian blood donors. More investigations are required to explain the presence of the HTLV-I tax sequence in seronegative blood donors.

Adolescent↗
PubMed1981

Direct relationship between blood pressure and blood viscosity in normal and hypertensive subjects. Role of fibrinogen and concentration.

Blood pressure and components of blood viscosity were measured in 49 normal subjects and in 49 untreated patients with essential hypertension. Blood viscosity values measured at six different shear rates were significantly correlated with blood pressure (r = 0.432 to 0.505, p less than 0.001). Blood viscosity was higher in hypertensive patients. This was due to both higher plasma viscosity (1.29 +/- 0.08 standard deviation versus 1.24 +/- 0.05 centipoise (cPs), p less than 0.001) and increased hematocrit values (44.4 +/- 4 percent versus 41.5 +/- 3 percent, p less than 0.005). When blood viscosity was evaluated in subgroups of normal and hypertensive subjects with matched hematocrit values, it remained higher in the hypertensive patients, and the relationship between blood pressure and viscosity was still significant. Regardless of the hematocrit value, fibrinogen levels were elevated in hypertensive patients (p less than 0.006) and, in association with the increased globulin concentration, fibrinogen was largely responsible for the increased plasma viscosity in hypertensive patients. Since the viscosity of defibrinated blood was similar in normal and hypertensive subjects with matched hematocrit values, the elevated fibrinogen level also affected whole blood viscosity. Defibrinated blood viscosity and arterial pressures were not correlated. These studies demonstrate a direct correlation between blood pressure and blood viscosity among normotensive and hypertensive subjects. This relationship is, in part, due to the rheologic effects of an elevated fibrinogen level and to an increased hematocrit value. The basis for hyperfibrinogenemia in hypertensive patients is unclear.

Adult↗