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Biomedical subjects

B Fuller

Publications and source records attributed to B Fuller.

At least 37 records · Page 2Linked to original sources
PubMed1996

Relationship of cues to assessed infant pain level.

Cues that 46 pediatric nurses with a BS in Nursing reported as key to their pain assessments of 88 videotaped infants, ages 0 to 12 months, are identified. Frequencies with which these cues were used for infants of different ages and the relationships between key cues and assessed levels of pain are described. Greater pain was strongly associated with tears, stiff posture, guarding, and fisting. Greater pain was moderately associated with inadequate type or dosage of analgesia, more recent surgery, inconsolability, difficult to distract, does not focus on surroundings, frown, grimace, wrinkled face, flushed face, pain cry, and increased arousal in response to touch of sore area. Internurse variability in cue use was sizable. Most of the often-used cues had weak or no association with assessed pain level. Only consolability, pain cry, grimace, and stiff posture were frequently used and correlated > .51 with assessed level of pain.

Clinical Nursing Research↗
PubMed1995

Requirement for extrathymic class I histocompatibility antigens for positive selection of thymus-derived T lymphocytes.

We have examined whether the thymus can produce immature T cell precursors for subsequent positive selection in the periphery. Using the intestine as a model system, we demonstrate that extrathymic MHC class I molecules positively select thymus-derived TCR-alpha beta CD8+ intestinal intraepithelial lymphocytes. Grafting of MHC class I+ thymus onto MHC class I- hosts resulted in the generation of donor and host-derived CD4-CD8+ T cells in lymph node, but few TCR-alpha beta CD4-CD8+ intraepithelial lymphocytes. The results indicate that the intestine can act as a site of positive selection for thymus-derived T cells. Bone marrow reconstitution studies demonstrated that non-hematopoietic, radiation-resistant cells, perhaps intestinal epithelial cells, were responsible for extrathymic positive selection of thymus-derived T cells. These findings demonstrate that the thymus can support organ-specific immunity via provision of targeted precursor populations.

Animals↗
PubMed1995

Repeatability and validity of a field kit for estimation of cholinesterase in whole blood.

OBJECTIVES: To evaluate a spectrophotometric field kit (Test-Mate-OP) for repeatability and validity in comparison with reference laboratory methods and to model its anticipated sensitivity and specificity based on these findings. METHODS: 76 farm workers between the age of 20 and 55, of whom 30 were pesticide applicators exposed to a range of organophosphates in the preceding 10 days, had blood taken for plasma cholinesterase (PCE) and erythrocyte cholinesterase (ECE) measurement by field kit or laboratory methods. Paired blinded duplicate samples were taken from subgroups in the sample to assess repeatability of laboratory and field kit methods. Field kits were also used to test venous blood in one subgroup. The variance obtained for the field kit tests was then applied to two hypothetical scenarios that used published action guidelines to model the kit's sensitivity and specificity. RESULTS: Repeatability for PCE was much poorer and for ECE slightly poorer than that of laboratory measures. A substantial upward bias for field kit ECE relative to laboratory measurements was found. Sensitivity of the kit to a 40% drop in PCE was 67%, whereas that for ECE was 89%. Specificity of the kit with no change in mean of the population was 100% for ECE and 91% for PCE. CONCLUSION: Field kit ECE estimation seems to be sufficiently repeatable for surveillance activities, whereas PCE does not. Repeatability of both tests seems to be too low for use in epidemiological dose-response investigations. Further research is indicated to characterise the upward bias in ECE estimation on the kit.

Adult↗
PubMed1995

Monitoring of surface mitochondrial NADH levels as an indication of ischemia during liver isograft transplantation.

Ischemia-reperfusion injury is a major cause of transplant dysfunction. One feature of this damage is mitochondrial dysfunction. The objective of this study was to determine whether surface fluorometric measurements of mitochondrial NADH can be made, and if the technique can detect differences in mitochondrial respiration between minimally stored 1 to 2 degrees C for 25 minutes (group 1, control) transplanted livers and those stored in hypertonic citrate at 1 to 2 degrees C (group 2) for 24 hours before transplantation. Measurements were made in livers isografted in 20 male Lewis rats. The technique is sufficiently sensitive to detect increased (nicotinamide-adenine dinucleotide (NADH) during dissection of hepatic vessels before ligation 0.52 +/- 0.04 (n = 14, P < .03) compared with the in situ exposed liver, 0.43 +/- 0.02 n = 14). Complete hepatic ligation resulted in a significant increase in NADH (1.22 +/- 0.10, n = 14), P < .0001) compared with hepatic artery ligation, which did not increase NADH levels. After storage, NADH levels increased (P < .02) but there was no significant difference between groups. In group 1, completion of portal vein (PV), suprahepatic vena cava (SVC), and descending vena cava anastomoses resulted in decreased NADH levels toward those after preparation of the vessels before ligation. However, there was a significant difference (P < .004) between the 25-minute and the 24-hour stored livers, 0.56 +/- 0.07 versus 0.23 +/- 0.04, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A prospective randomized clinical trial of liver preservation using high-sodium versus high-potassium lactobionate/raffinose solution.

High-sodium as opposed to high-potassium lactobionate/raffinose preservation solution offers potential advantages in improving the quality of liver storage by reducing potassium-induced vasoconstriction and preventing hyperkalaemia on reperfusion. In our study we evaluated in a prospective trial (encompassing 40 consecutive cadaver donor hepatic retrievals and subsequent transplants) the efficacy of a high-sodium formulation versus the standard high-potassium solution. Quality of preservation was assessed by clinical indices of liver function in the intraoperative and early postoperative phases, including measurements of requirements for blood and blood products and potassium, circulating liver enzymes and bilirubin. Frequencies of acute rejection episodes and primary non-function were also recorded. No significant differences were evident in any of the measured parameters. Thus a sodium-based solution can be used for hepatic preservation, advancing the possibility that it may be possible to develop a single storage solution for clinical multi-organ donor operations.

Adult↗
PubMed1992

Plasma membrane water permeabilities of human oocytes: the temperature dependence of water movement in individual cells.

Membrane water permeability values were measured in individual fresh human pre-ovulatory oocytes using real time microscopy in a microscope diffusion chamber. The cells were exposed to anisosmotic conditions, their volume responses measured, and from these data the Lp values were computed employing the Kedem-Katchalsky analyses of irreversible thermodynamics. Lp values were measured at four temperatures for each oocyte between 37 degrees C and 10 degrees C, and the temperature-related Arrhenius activation energy (Ea) calculated. It was apparent that individual oocytes exhibited a wide range of Lp values; at 37 degrees C Lp values ranged between 0.33 and 1.80 microns/atm/min. However, each oocyte exhibited the expected inverse linear correlation between Lp and temperature, with high linear correlations (R2 values between 0.73 and 0.96). A mean value for Ea of 8.61 +/- 5.11 Kcal/mol was computed. It is apparent that pre-ovulatory human oocytes express a range of biological diversity in terms of membrane water transport, and this fact needs to be considered when attempting to formulate cryopreservation protocols for storage of these oocytes.

Cell Membrane Permeability↗
PubMed1992

The effect of cold storage of rat thoracic aortic rings in organ preservation solutions--a study of receptor-linked vascular prostacyclin synthesis.

An important aspect of organ preservation is the maintenance of intrinsic dilator and antithrombotic mechanisms of blood vessels. Blood vessels synthesize prostacyclin (PGI2), a potent vasodilator and inhibitor of platelet adhesion and aggregation. PGI2 synthesis is controlled by complex mechanisms including adrenoceptor-linked calcium influx and protein kinase C. Since organ preservation solutions may influence these mechanisms, we investigated the effect on in vitro PGI2 synthesis of cold storage of rat aortic rings in lactobionate-raffinose solution (LRS) and hypertonic citrate kidney preservation solution (KPS) on in vitro PGI2 synthesis. Acute incubation of aortic tissue in both preservation solutions at 37 degrees C (compared with minimal essential medium) completely inhibited PGI2 synthesis when stimulated with noradrenaline (NA), phorbol ester (a protein kinase C activator), NaF (a G protein activator), or A23187. Following storage of aortic rings at 4 degrees C (for up to 72 hr) in LRS and KPS, subsequent washing and incubation in MEM, PGI2 synthesis was initially markedly enhanced in response to NA when compared with tissues stored in MEM. These enhanced responses disappeared, and PGI2 synthesis returned to normal following 1 hr incubation of tissues in MEM at 37 degrees C. These data demonstrate that cold storage in preservation fluids exerts minimal deleterious effects, not only on PGI2 synthesis, but possibly on other key processes (calcium homeostasis, protein kinase C activity) in blood vessels.

Adenosine↗
PubMed1992

The effects of inhibition of plasma cholinesterase and hepatic microsomal enzyme activity on cocaine, benzoylecgonine, ecgonine methyl ester, and norcocaine blood levels in pigs.

We measured the blood levels of cocaine and its three major metabolites, benzoylecgonine, ecgonine methyl ester, and norcocaine, in three groups of male pigs weighing about 26 kg (25.75 +/- 0.25 kg) to determine the effects of inhibition of plasma cholinesterase and hepatic microsomal enzyme activity on cocaine metabolism. In addition, systemic elimination half-life, volume of distribution, and clearance of cocaine were calculated for the three groups. Group 1 pigs (n = 4) were pretreated with normal saline solution, group 2 pigs (n = 4) were pretreated with tetraisopropyl pyrophosphoramide, a specific plasma cholinesterase inhibitor, and group 3 pigs (n = 4) were pretreated with cimetidine, a hepatic microsomal enzyme inhibitor, all administered intramuscularly. Pigs were anesthetized with intravenous sodium thiopental; a carotid arterial cannula and an external jugular catheter were then inserted for the administration of cocaine and for blood sampling. Forty-five minutes later, when pigs were again completely awake, cocaine 3 mg/kg was given intravenously. Arterial blood samples were collected for the analysis of cocaine and cocaine metabolite levels just before and at 5, 10, 15, 30, 45, 60, 120, 180, and 1440 minutes after the administration of cocaine. Cocaine and cocaine metabolite blood levels were analyzed with high-pressure liquid chromatography methods and plasma cholinesterase activity was measured with a colorimetric method. The blood levels of cocaine and cocaine metabolites were significantly different among the three groups (p less than 0.05, analysis of variance). Statistically significant differences in half-life, volume of distribution and clearance were also seen among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Seeding of human microvascular endothelial cells onto polytetrafluoroethylene graft material.

Microvascular endothelial cells from human omental samples were isolated and grown. Adhesion to polytetrafluoroethylene vascular graft material was then studied using scanning electron microscopy and adhesion of cells labelled with indium-111. Grafts coated with fibronectin and type I collagen were found to promote the best adhesion of cells at times up to 90 min. A coating of blood clot matrix was less effective but still resulted in a threefold increase in cell adhesion compared with controls.

Blood Vessel Prosthesis↗
PubMed1991

Orthostatic vital signs in emergency department patients.

STUDY OBJECTIVE: To examine the variability and define the normal ranges of orthostatic vital signs in an emergency department population. DESIGN: Descriptive. TYPE OF PARTICIPANTS: Adult ED patients with no history of recent blood or fluid losses. MEASUREMENTS: Lying and standing heart rate and blood pressure measured by an automated instrument. RESULTS: In 132 presumed euvolemic patients, the statistical normal ranges (mean +/- 2 SD) of orthostatic vital signs were wide: on standing, the heart rate range was from decreases 5.0 to increases 39.4 beats per minute; for systolic blood pressure, the range was decreases 20 to increases 25.7 mm Hg; and for diastolic blood pressure, the range was decreases 6.4 to increases 24.9 mm Hg. In this sample, 43% had "positive" orthostatic vital signs according to currently accepted values. CONCLUSION: The data from this study indicate that there is a wider than expected variation in orthostatic vital signs among presumed euvolemic ED patients.

Adolescent↗
PubMed1991

Fertilization and development of the human oocyte following exposure to cryoprotectants, low temperatures and cryopreservation: a comparison of two techniques.

Both glycerol and dimethyl sulphoxide (DMSO) equilibration prior to cryopreservation produced adequate rates of survival and development to the hatching blastocyst stage for mouse oocytes using the two chosen cooling and warming regimes. Successful fertilization of human oocytes and further development of the embryos produced, was achieved following equilibration with DMSO at 0 degrees C. Although fertilization of fresh human ova previously exposed to glycerol was recorded, all oocytes with two pronuclei failed to continue to undergo cell division by 48 h in culture. Following cryopreservation, human oocytes were successfully inseminated after equilibration with both glycerol and DMSO. However, cell division to the 2-cell stage was recorded in only one oocyte which had undergone exposure to DMSO, freezing and thawing. No cell divisions were recorded after glycerol cryopreservation, or even after simple exposure to glycerol. Therefore it appears that DMSO and slow cooling may be the best protocol, although further evaluation will be necessary.

Animals↗