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At least 541 records · Page 30Linked to original sources
PubMed1999

Circadian blood pressure during the early course of type 1 diabetes. Analysis of 1,011 ambulatory blood pressure recordings in 354 adolescents and young adults.

OBJECTIVE: Little information is available on the early course of hypertension in type 1 diabetes. The aim of our study, therefore, was to document circadian blood pressure profiles in patients with a diabetes duration of up to 20 years and relate daytime and nighttime blood pressure to duration of diabetes, BMI, insulin therapy, and HbA1c. RESEARCH DESIGN AND METHODS: Ambulatory profiles of 24-h blood pressure were recorded in 354 pediatric patients with type 1 diabetes (age 14.6 +/- 4.2 years, duration of diabetes 5.6 +/- 5.0 years, follow-up for up to 9 years). A total of 1,011 profiles were available for analysis from patients not receiving antihypertensive medication. RESULTS: Although daytime mean systolic pressure was significantly elevated in diabetic subjects (+3.1 mmHg; P < 0.0001), daytime diastolic pressure was not different from from the height- and sex-adjusted normal range (+0.1 mmHg, NS). In contrast, both systolic and diastolic nighttime values were clearly elevated (+7.2 and +4.2 mmHg; P < 0.0001), and nocturnal dipping was reduced (P < 0.0001). Systolic blood pressure was related to overweight in all patients, while diastolic blood pressure was related to metabolic control in young adults. Blood pressure variability was significantly lower in girls compared with boys (P < 0.01). During follow-up, no increase of blood pressure was noted; however, diastolic nocturnal dipping decreased significantly (P < 0.03). Mean daytime blood pressure was significantly related to office blood pressure (r = +0.54 for systolic and r = +0.40 for diastolic pressure); however, hypertension was confirmed by ambulatory blood pressure measurement in only 32% of patients with elevated office blood pressure. CONCLUSIONS: During the early course of type 1 diabetes, daytime blood pressure is higher compared with that of healthy control subjects. The elevation of nocturnal values is even more pronounced and nocturnal dipping is reduced. The frequency of white-coat hypertension is high among adolescents with diabetes, and ambulatory blood pressure monitoring avoids unnecessary antihypertensive treatment.

Adolescent↗
PubMedDate not supplied

Autologous blood transfusion: evaluation of an alternative strategy in reducing exposure to allogeneic blood transfusion.

The perceived risk of transfusion-transmitted disease led to the rejuvenation of autologous blood transfusion (ABT). ABT, a process in which the blood donor and recipient are the same, is increasingly becoming an integral component of the elective surgical protocol in many institutions. Various methods of ABT are being utilized. These include: preoperative blood donation, in which the patient donates blood prior to surgery and the blood is stored for an expected need during or after surgery; acute normovolemic hemodilution, in which blood is collected immediately prior to surgery and replaced with cell free fluids and then returned to the patient upon need; intraoperative blood salvage in which blood is collected from the surgical field and is reinfused after being washed and finally, postoperative blood salvage in which collected shed blood from surgical drains is reinfused to the patient. Although ABT is known to reduce the risk of allogeneic blood transfusion, it is not risk free and should be evaluated in relation to the patient's clinical picture. The combination of various methods of ABT in addition to the proper utilization of blood may consequently lead to the elimination of patients' exposure to allogeneic blood transfusion in many surgical procedures.

Blood Preservation↗
PubMed1994

[Characteristics of blood pressure regulating endocrinological factors in elderly essential hypertensives].

Plasma renin activity (PRA) was lower in elderly normotensive subjects and essential hypertensives (EHT), and a significant negative correlation was found between PRA and age in both groups. In EHT, the proportion of the low renin group to total EHT increased with aging. There was a significantly positive correlation between plasma norepinephrine (PNE) and age in NT, but not in EHT. The mean value of PNE in young subjects was significantly higher in EHT than in NT, but not in the middle-aged and elderly groups, suggesting the important role of PNE in young EHT. Power spectral analysis revealed a significant reduction of both sympathetic and parasympathetic activity with aging in NT and EHT, indicating much caution may be required if sympathetic nerve activity is evaluated only by PNE levels in elderly EHT. The expanded plasma volume was another characteristic in elderly EHT, and suppressed activity of renal kallikrein-kinin, prostaglandin and dopamine may be involved with its mechanisms. Regarding insulin sensitivity in elderly EHT, it was shown that 1) the reduction of insulin sensitivity plays some role in age related acceleration of hypertension and glucose intolerance, 2) selective insulin resistance with respect to glucose metabolism already exists at lower ages in EHT, and 3) both Na retention and pressor system activation via insulin action might be a cause of blood pressure elevation in EHT.

Adult↗
PubMed2001

Solitary blood cultures: a College of American Pathologists Q-probes study of 132,778 blood culture sets in 333 small hospitals.

OBJECTIVE: To determine the frequency with which solitary blood culture samples were submitted to laboratories serving small hospitals and to ascertain whether certain hospital practices relating to the performance of blood cultures were associated with lower solitary blood culture rates (SBCRs). DESIGN: Participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data prospectively on the numbers of solitary blood culture sets from adult patients submitted to their laboratories and answered questions about their institutions' practice characteristics relating to the collection of blood culture specimens. SETTING AND PARTICIPANTS: Three hundred thirty-three public and private institutions with a median occupied bed size of 57. Participants were located in the United States (n = 329), Canada (n = 3), and Australia (n = 1). MAIN OUTCOME MEASURE: The solitary blood culture rate was defined as the number of instances in which only 1 blood culture venipuncture was performed on an individual patient during a 24-hour period divided by the total number of blood culture venipunctures that were performed during the study period. RESULTS: Participants submitted data on 132 778 adult patient blood culture sets. The SBCRs were 3.4% or less in the top-performing 10% of participating institutions (90th percentile and above), 12.7% in the midrange of participating institutions (50th percentile), and 42.5% or more in the bottom-performing 10% of participating institutions (10th percentile and below). In half the participating institutions, the SBCRs for inpatients were 8.3% or less and for outpatients, 22% or less. Solitary blood culture rates were lower for institutions in which phlebotomists rather than nonphlebotomists routinely collected blood culture specimens, in which internal policies required drawing at least 2 blood culture sets, in which hospital personnel contacted clinicians when their laboratories received requests for solitary blood culture sets, and in which quality control programs monitored SBCRs routinely. CONCLUSIONS: Hospitals can achieve SBCRs under 5%. Those hospitals with particularly high SBCRs may lower their rates by altering certain institutional practices.

Adult↗
PubMed2001

[The difference of intracellular cytokines produced by different lymphocyte subsets of cord blood and adult peripheral blood].

OBJECTIVE: To explore the difference of intracellular cytokines between cord blood and adult peripheral blood and elucidate its significance for GVHD. METHOD: Different lymphocyte subsets were categorized in cord and adult peripheral blood by monoclonal antibodies with 3 color fluorescence using flow cytometry. The IL-2, TNF-alpha and IFN-gamma produced by various lymphocyte subsets were compared between the two groups. RESULT: (1) In cord blood, dominant T cells were CD(4)(+)CD(45RA)(+), while the major T cells were both CD(4)(+)CD(45RO)(+) and CD(8)(+)CD(45RO)(+) in adult peripheral blood. (2) The quantities of IL-2, TNF-alpha and IFN-gamma produced by cord blood lymphocytes were lower than that of adult peripheral blood lymphocytes. Moreover, the majority of cells that produced cytokines in the cord blood were CD(4)(+)CD(45RA)(+), but in adult peripheral blood were mainly CD(4)(+)CD(45RO)(+) and CD(8)(+)CD(45RO)(+). CONCLUSION: As compared with adult peripheral blood, the cord blood not only possessed different proportion of lymphocyte subsets, but also significant low level of cytokines. The differences of various lymphocyte subset proportions and lower level of cytokines in cord blood probably related to the lower incidence of GVHD in cord blood stem cell transplantation.

Adult↗
PubMed1991

Effects of reducing uterine blood flow on fetal blood flow distribution and oxygen delivery.

We examined the effect of graded reduction in uterine blood flow on distribution of cardiac output and oxygen delivery to fetal organs and venous blood flow patterns in 9 fetal sheep using the radionuclide-labeled microsphere technique. We reduced uterine blood flow in two steps, decreasing fetal oxygen delivery to 70% and 50% of normal, and compared the results with those from a similar study from our laboratory on graded umbilical cord compression. With 50% reduction in fetal oxygen delivery, blood flow and the fraction of the cardiac output distributed to the brain, heart, and adrenal gland increased and that to the lungs, carcass, skin, and scalp decreased. Oxygen delivery to the brain and myocardium was maintained, while that to the adrenal doubled, and that to the brain stem increased transiently. The decrease in oxygen delivery to both carcass and lower body segment correlated linearly with oxygen consumption (P less than 0.001). The proportion of umbilical venous blood passing through the ductus venosus increased from 44.6% to 53% (P less than 0.05). The preferential distribution of ductus venosus blood flow through the foramen ovale to the heart and brain increased, but that to the upper carcass decreased so that ductus venosus-derived blood flow to the upper body did not change. Hence, the oxygen delivered to the brain from the ductus venosus was maintained, and that to the heart increased 54% even though ductus venosus-derived oxygen delivery to the upper body fell 34%. Abdominal inferior vena caval blood flow and its contribution to cardiac output decreased, but the proportion of the abdominal inferior vena caval blood distributed through the foramen ovale also increased from 23.0 to 30.9%. However, the actual amount of inferior vena caval blood passing through the foramen ovale did not change. There was a 70% fall in oxygen delivery to the upper body segment from the inferior vena cava. A greater portion of superior vena caval blood was also shunted through the foramen ovale to the upper body, but the actual amounts of blood and oxygen delivered to the upper body from this source were small. Thus, graded reduction of uterine blood flow causes a redistribution of fetal oxygen delivery and of venous flow patterns, which is clearly different from that observed previously during graded umbilical cord occlusion.

Animals↗
PubMed1994

[The present possibilities for routine use of blood-saving measures from the anesthesiologic point of view--theoretical basis and clinical practice. II: Perioperative retransfusion of acute blood loss; plasmapheresis].

Intra- and postoperative blood-salvage with consecutive retransfusion represent an established part within the "Concept of Autologous Transfusion (CAT)". According to the processing technique of the blood salvaged there exist two different systems: Autologous Transfusion System II (ATS II) and Autologous Transfusion System III (ATS III). By using ATS II blood (with or without anticoagulation) is collected within a collecting reservoir after having passed a rough-filter-system. Passing a fine-filter-system the blood collected is retransfused into the patient without any preceding processing (autologous direct-retransfusion, ADR). Because of the activation of the coagulation proteins by the tissue and by the collection system as well as due to the destroyed red blood cells, the white blood cells, the platelets and the free plasma hemoglobin the patient is transfused with an autologous "whole-blood-like product" of minor quality. By administration of ATS III blood is collected and anticoagulated and passes a rough-filter as well; by processing the blood by means of centrifugation and separation and by washing the damaged red blood cells, a great part of the white blood cells, of the platelets and of the plasma hemoglobin (and of the anticoagulatory drug) is eliminated resulting in a washed autologous product, which mainly consists of red blood cells, which are retransfused into the patient through a fine-filter system. This means, that the autologous product obtained by the two different systems differs both regarding its quality and the plasmatic and corpuscular contents. However, undoubtedly either system is able to effectively reduce the need for homologous blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMed1976

Peripheral arterial insufficiency, effect of physical training on walking tolerance, calf blood flow, and blood flow resistance.

Twenty-three patients with intermittent claudication were submitted to physical training during 4-6 months. Eleven other patients with intermittent claudication served as a control group and were given placebo tablets during the same period. The aim of the investigation was to study the influence of physical training on the blood flow conditions in the calf. The effect of treatment on walking tolerance, on calf blood flow, blood flow resistance, and systolic blood pressure graident between the systemic circulation and the vascular bed in the calf was studied. Half a year after the end of the treatment period the patients were reexamined. The walking tolerance increased in both groups but more in the trained group. The increase in walking tolerance even in the control group was caused by the fact that the control group began to train to some extent. In neither group the maximal calf blood flow changed significantly compared with the pretreatment values. The maximal blood flow showed an increasing trend in the training group after a period fo 4 months compared with the control goupr (2p greater than 0.10). The blood flow resistance at maximal dilatation did not change significantly as compared with the initial values in any of the groups, but there was a significant difference (2p greater than 0.05) between the two groups with a decrease in the training group after 4 months. The changes in maximal calf blood flow and the changes in blood flow resistance at maximal dilatation were not related to the changes in walking tolerance. Half a year after the treatment period the walking tolerance had not decreased and there was no difference between the two groups. The maximal calf blood flow, the blood flow resistance, and the systolic pressure gradient were unchanged in comparison with the pretreatment values and there were no statistically significant differences between the two groups. The small changes in blood flow conditions observed after physical training cannot be the only factor explaining the well known improvement in walking tolerance. However, training may cause a redistribution of the blood flow in the working muscle.

Aged↗
PubMed1974

Capacitance effects and blood reservoir function in the splanchnic vascular bed during non-hypotensive haemorrhage and blood volume expansion in anaesthetized cats.

1. These experiments were designed to measure how much blood is mobilized from or pooled in the liver, spleen and gastro-intestinal tract to compensate for a haemorrhage or infusion of blood.2. Hepatic volume, splenic weight and intestinal volume were recorded in cats anaesthetized with sodium pentobarbitone. Whole blood was removed or infused at rates of 0.5-0.6 ml. kg(-1).min(-1) until 10 ml./kg (19% blood volume) had been removed or 18 ml./kg (34% blood volume) had been infused. These blood volume changes produced only small changes in arterial and portal pressures except after removal of 8 ml./kg (15% blood volume) when arterial pressure began to decrease rapidly.3. With small haemorrhages of up to 4% blood volume, the liver contributed 16%, the gastro-intestinal tract 23% and the spleen a negligible proportion of the blood volume removed. With haemorrhages of 15% blood volume, the liver contributed 21%, the gastro-intestinal tract 22% and the spleen 19% of the volume removed; a total splanchnic contribution of 62%.4. During infusions of 5-18 ml./kg (10-34% blood volume), the liver pooled 20%, the gastro-intestinal tract 40% and the spleen 6% of the volume infused; a total splanchnic contribution of 66%.5. It is concluded that the splanchnic bed mobilizes or pools up to 65% of the volume of blood removed from or infused into the cats. The mechanisms responsible for this blood reservoir function are discussed. While several factors may be involved, it seems likely that a reflex regulation involving atrial receptors and the sympathetic innervation of the splanchnic capacitance vessels is of predominant importance.

Animals↗
PubMed1984

Experimental hypervolemic hemodilution: physiological correlations of cortical blood flow, cardiac output, and intracranial pressure with fresh blood viscosity and plasma volume.

Rheological, cerebrovascular, and cardiovascular alterations induced by serial plasma volume (PV) expansion were evaluated in splenectomized dogs. Seven dogs received two infusions of autologous plasma within 120 minutes; each infusion equaled 20% of the respective dog's total blood volume (TBV). The PV increased 31% and then another 26% after the two respective infusions, and the hematocrit (Hct) was obligatorily decreased by 22% during the experiment. The fresh blood viscosity at the shear rate of 10 sec-1 varied inversely with the TBV and the PV and correlated directly with the Hct after these plasma infusions. Cardiac output (CO) increased 71% after the two infusions without significant alterations in mean arterial blood pressure. Additionally, CO was inversely related to both Hct and blood viscosity. Although the 15% rise in regional cortical blood flow (rCoBF) in the territory of the middle cerebral artery did not reach statistical significance, the rCoBF was related inversely to both Hct and blood viscosity and directly to TBV, PV, and CO after the plasma infusions. Cortical vascular resistance (CVR) decreased 18% after the two infusions. The CVR correlated inversely with PV and directly with Hct and blood viscosity. Our data suggest that hypervolemic hemodilution with expansion of PV increases CO more than cerebral blood flow in normal brain. Fresh blood viscosity seems to be a major factor determining CO and cerebral perfusion after IV expansion. This study adds support to the hypothesis that reductions of blood viscosity account for the direct relationship between cerebral blood flow and CO observed after intravascular volume expansion with hemodiluting agents. Hypervolemic hemodilution with plasma reduces CVR, possibly secondary to its effect on blood viscosity, and also raises intracranial pressure.

Animals↗
PubMed1975

[Our experiences in the blood supply by means of a blood bank].

"GIVE US BLOOD TODAY, YOU'LL GET IT WHEN YOU NEED IT". Under this slogan the blood transfusion service gathers the blood donors offering, in return for the given blood the security that, any moment and in required quantities, the blood will be provided for every donor i.e. every member of any collective that acts on the request and "deposits" blood in so called blood banks", at least twice a year. Agitation among the prospective blood donors is completely confided to prominent people, social and medical workers, who do it permanently, and not from time to time, and who, if possible, are also blood donors, and owing to their own example, more convincing. The obligations between the blood transfusion service and "the investors" are regulated by oral agreement. It is noticed that the mutual moral obligation has more positive influence on the fulfillment of obligation than the administrative measure--a contract. According to this experience, individual work, a personal contact with prospective blood donors, and the feeling of personal security that is offered to them give the best results in motivating the people to become blood donors.

Blood Banks↗
PubMed1994

[A retrospective study of the practice of "look-back" procedures, on the incidence of HIV-1/2-positive blood donors and the risk of transfusion-associated HIV infection in public-community blood banks in Germany].

OBJECTIVE: 'Look-back' investigations can reveal and confirm transfusion-transmitted infectious diseases and provide data for risk calculations of blood transfusions. DESIGN: In 1993 we distributed a questionnaire to all governmental and communal blood transfusion services in Germany. The questionnaire comprised questions about the methods, numbers and results of look-back investigations in case of HIV-1/2-positive blood donors with previous donations and in case of HIV-1/2-positive recipients of blood transfusions. The questionnaire was returned by almost all blood transfusion services (n = 75). One additional institution briefly informed us by telephone. SETTING: All governmental and communal blood transfusion services in Germany. PATIENTS: All recipients of blood or blood products in the years from 1985 till the end of 1992 who were treated in hospitals supplied by the transfusion services defined above. INTERVENTIONS: None. RESULTS: All blood transfusion services included have performed look-back studies since 1985. The methods used varied considerably. The interval of looking back mostly was sufficient. A main problem was the poor documentation in the medical records. The incidence of HIV-1/2-positive blood donations decreased from 11.6/100,000 in 1985 to 3.4/100,000 in 1992. Only 7 of 73 transfusion-transmitted HIV infections derived from transfusions after the introduction of HIV testing (October 1985). Since then the risk of transfusion-transmitted HIV infection can be calculated as 1/800,000 whole-blood donations of governmental and communal blood transfusion services. CONCLUSIONS: Since the introduction of HIV testing the risk of transfusion-transmitted HIV infection in Germany has been very low, at a rather stable rate of 1/800,000. The data from the look-back studies confirm the previous estimations of the risk of transfusion-transmitted HIV infections, which was calculated by the HIV incidence in the donor population. Nevertheless there is a need for standardization of look-back investigations.

AIDS Serodiagnosis↗
PubMed1989

Blood use in head and neck tumor surgery. Potential for autologous blood.

Recent increased concern regarding the risks of homologous blood transfusion led us to examine the use of blood products for head and neck tumor surgery. Major head and neck surgical procedures at three University of Washington (Seattle)-affiliated hospitals during 1987 were reviewed. Seventy-seven patients were identified. Parameters studied included the following: tumor site and stage, prior treatment, surgical procedure, preoperative and postoperative hematocrit values, estimated blood loss, operative and postoperative blood product use, and operative time. Data were grouped by procedure. Maxillectomy/midface procedures showed the highest average estimated blood loss (1037 mL) and the highest average blood use (1.5 units), followed by composite resections (883 mL and 0.8 units) and laryngectomies (724 mL and 0.9 units). When the data were subgrouped, larynogopharyngectomy (1450 mL and 4.0 units) and composite resection with mandibular swing (1300 mL and 1.0 units) showed the highest blood loss and blood product use. In the assessable groups, previous administration of radiation did not make a significant difference in blood loss or procedure time. However, blood loss correlated well with procedure time in all groups. The great majority of patients met all requirements to function as blood donors (84%). Sixty-five percent of patients met all criteria and used less than 2 units of blood, making autologous blood a reasonable option for the majority of patients with head and neck tumors.

Blood Transfusion, Autologous↗
PubMedDate not supplied

Basal blood pressure variability and reactivity of blood pressure to emotional stress in essential hypertension.

Blood pressure variability under basal conditions and blood pressure reactivity to emotional stress were studied in 38 hypertensives and 13 normotensives. Systolic basal blood pressure variability correlated with systolic blood pressure reactivity. Variability increased with higher basal blood pressure. Thus in the hypertension group the blood pressure variability was greater than in the normotension group. Besides, the hypertension group showed a greater reactivity of systolic blood pressure to emotional stress, too. An influence of age on basal blood pressure, blood pressure variability, and reactivity could be evaluated; but no influence of sex on these parameters was detected. The results indicate that variability and reactivity of blood pressure can be referred to a common central nervous blood-pressure-regulating mechanism. As both parameters are increased in hypertension, a greater lability of blood pressure must be assumed. This greater lability may be attributed to a stronger neurogenic influence or to structural changes of peripheral blood vessels.

Adult↗
PubMed1976

[The value of the thermocouple in the measurement of the gastric mucosal blood-flow. The influence of the occlusion of the celiac artery and prostaglandin E1 on the gastric mucosal blood flow. An experimental study in animals (author's transl)].

The study has been carried out to ensure the positive evidence of the measurement of the gastric mucosal blood-flow with the aid of the thermocouple (heat-clearance technique). The experiments have shown that the suction pressure of 600 mm mercury column which was used to fix the Thermocouple to the mucosa was indispensable in order to assess the blood-flow in the entire depth of the mucosa. Changes in the mucosal blood-flow are measuured at the same rate in all quadrants of the gastric corpus. The measuring of the blood-flow of a well circumscribed area of the mucosa is therefore representative for the entire corpus. Vasopressin led to a significant reduction of the gastric mucosal blood-flow measured with heat-clearance as well aminopyrine-clearance. There was a linear correlation between the results of both methods. Vasopressin selectively reduces the blood-flow of the gastric mucosa but not of the submucosa, the muscular layer and the serosa. Therefore it seems to be probable that changes in mucosal blood-flow selectively can be measured with the aid of the thermocouple. After previous stimulation with pentagastrin neither mucosal blood-flow nor acid secretion of the stomach were influenced by the occlusion of the celiac artery by 25 %. The occlusion of the celiac artery by 50 % reduced significantly the pentagastrin-stimulated gastric mucosal blood-flow whereas the acid secretion was not influenced. Prostaglandin E1 at a dose rate of 2 mug/kg-h increased significantly arterial and mucosal blood-flow as well as acid secretion of the stomach. In comparison PGE1 administered at a dose rate of 4 mug/kg-h reduced significantly gastric mucosal blood-flow and gastric secretion. PGE1 at a dose rate of 8 mug/kg-h did not produce any significant changes in blood-flow and secretion. The results suggested that the changes of gastric secretion observed with PGE1 were the consequence of primary changes in the gastric mucosal blood-flow.

Animals↗
PubMedDate not supplied

The role of blood platelets in nucleoside metabolism: assay, cellular location and significance of thymidine phosphorylase in human blood.

The enzyme thymidine phosphorylase (thymidine: orthophosphate deoxyribosyltransferase, EC 2.4.2.4), which plays a crucial role in nucleic acid metabolism in both prokaryotic and eukaryotic cells by regulating the availability of thymidine, is present in mammalian blood. Here we describe a simple, rapid HPLC-based micromethod for the assay of blood thymidine phosphorylase. We have arbitrarily defined 1 unit of blood thymidine phosphorylase activity as the activity required to produce a 1-nM increment in the plasma concentration of thymine after incubation for 1 h at 37 degrees C with a saturating concentration of exogenous thymidine. In normal adults, whole (peripheral venous) blood thymidine phosphorylase activity with blood cells intact was 64 +/- 11 units (mean +/- S.D., n = 20, range 45-89). The apparent Michaelis constant for thymidine was of the order of 10(-4) M but varied nearly 5-fold between different individuals. Activity increased when blood cells were permeabilised or lysed with non-ionic detergents, implying that thymidine phosphorylase is an intracellular enzyme which may be influenced by exogenous as well as intracellular factors. When blood from normal donors was fractionated, thymidine phosphorylase activity consistently co-isolated with platelets. Whole-blood thymidine phosphorylase activity correlated well with platelet parameters. Although thymidine phosphorylase activity was also detected in plasma and serum, the small size and notorious fragility of platelets suggest its platelet origin. Blood from leukaemic donors showed significantly increased thymidine phosphorylase activity compared to normal controls (mean activity +/- S.D. was 96 +/- 27 units; range 58-140, n = 8). Thymine formation from thymidine was temperature- and pH-dependent in whole blood. 2'-Deoxyuridine and 3 of its 5-halogenated analogues (but not 3'-azido-3'-deoxythymidine (AZT), were catabolised by blood thymidine phosphorylase, even during blood clotting at room temperature. Assumptions about in vivo concentrations of these compounds should therefore be interpreted cautiously. In the presence of high concentrations of thymine and suitable deoxyribose donors, small amounts of thymidine were formed in some blood samples, so it is conceivable that thymidine catabolism may be reversible in vivo under some circumstances.

Blood Platelets↗
PubMed1999

Use of blood and blood products.

It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice, are time-consuming, expensive, and stressful to the animal. Acute loss of 20% to 25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7% to 12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five percent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10 to 20 mL/kg recipient weight is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10 to 15 mL of blood/kg body weight at 2- to 4-week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood cross-matching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 mL of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria, hemoglobinuria, collapse, apnea, and opisthotonos. Intravenous epinephrine HCl 1:1000 can be administered (0.2 to 0.5 mL) intravenously or (4 to 5 mL) intramuscularly (preferable) if clinical signs are severe. Pretreatment with antipyretics and slowing the administration rate may decrease the febrile response. Blood or plasma administered too rapidly will also result in signs of cardiovascular overload, acute heart failure, and pulmonary hypertension and edema. Furosemide and slower administration of blood or plasma should alleviate this problem. Administration rates have been suggested starting from 10 mL/kg/hr; faster rates may be necessary in peracute hemorrhage. Plasma should be administered when failure of absorption of passive maternal antibody has occurred or when protein-loosing enteropathy or nephropathy results in a total protein of less than 3 g/dL or less than 1.5 g albumin/dL. Plasma can be stored at household freezer temperatures (-15 to -20 degrees C) for a year; coagulation factors will be destroyed after 2 to 4 months when stored in this manner. To maintain viability of coagulation factors, plasma must be stored at -80 degrees C for less than 12 months. When administering plasma, a blood donor set with a built-in filter should always be used. When bovine plasma is thawed, precipitants form in the plasma and infusion of these microaggregates may result in fatal reactions in the recipient.

Anemia↗
PubMed1997

Prediction of young adult blood pressure from childhood blood pressure, height, and weight.

To assess the ability of childhood blood pressure, height, and weight to predict young adult blood pressure, the authors examined data obtained over multiple visits for four years on 339 children aged 8-18 years in East Boston, Massachusetts. These subjects were again seen 8-12 years later when they were aged 20-26 years. Multivariate regression models were used to predict true blood pressure in young adulthood from observed childhood measurements closest to age 10 (n = 219), adjusting for within-person variability. Without adjusting for childhood blood pressure, childhood height, weight and body mass index were at least marginally associated with young adult systolic blood pressure in boys and girls, with similar coefficients for each gender. The strongest predictor was weight (beta = 0.6 mmHg/10 lbs for girls, and beta = 0.7 mmHg/10 lbs for boys), and height was no longer predictive with weight in the model. With childhood blood pressure included, neither childhood height nor weight were predictors of future systolic blood pressure. However, change in height and weight were predictors of future systolic blood pressure. Weight change was a stronger predictor in girls than boys with beta = 0.9 mmHg/10 lbs. For diastolic blood pressure, height and weight had limited predictive ability in these data. These models, which allow for both between- and within-person variability in young adulthood, may be used to estimate the predictive value for future high blood pressure of a child's current blood pressure, height and weight, as well as future change in height and weight. These data suggest that the effects of childhood height and weight on future blood pressure may be negligible given childhood blood pressure, but that later height and weight remain predictive.

Adolescent↗