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At least 883 records · Page 49Linked to original sources
PubMed2004

Mechanical behavior of bioactive composite cements consisting of resin and glass-ceramic powder in a simulated body fluid: effect of silane coupling agent.

Time-dependent strength behavior was investigated for bisphenol-a-glycidyl methacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) resin cements combined with glass-ceramic A-W filler treated with various kinds of silane coupling agents. The fracture strength of the composite resin cements was measured by three-point bending as a function of stressing rate in a simulated body fluid (SBF), and thereby the stress-corrosion susceptibility constant was evaluated. The fracture strength was found to depend on the kind of coupling agent used. For the present Bis-GMA/TEGDMA resin, the silane coupling agents without hydrophilic amine groups can be used to obtain good adhesion between resin and A-W filler owing to their nature of co-polymerizing with the resin. On the other hand, all the composite resin cements showed nearly the same degree of stress-corrosion susceptibility whether the A-W fillers were treated or untreated with silane coupling agents. This means that the stress-corrosion susceptibility of the present composite cements is predominantly affected by that of the matrix resin. Thus, the microcrack formation and growth at the resin matrix near particle - resin interface were thought to determine overall time-dependent strength behavior of the composite cements.

Biocompatible Materials↗
PubMed2005

A new method for the determination of arylesterase activity in human serum using simulated body fluid.

Arylesterase activity (EC 3.1.1.2), one of the three functions of the paraoxonase enzyme (PON1), is thought to protect low-density lipoproteins (LDL) and high-density lipoprotein (HDL) from oxidation and to facilitate reverse cholesterol transport. The Eckerson et al. method, which employs Tris/HCl buffer, has been extensively used and could be considered as the reference method, although it shows relatively low precision and reproducibility. Using simulated body fluid (SBF), which simulates blood electrolyte composition, a significant improvement in arylesterase activity determination was achieved. Modifications of SBF bicarbonate and chloride concentrations did not result in further improvements. To validate this method arylesterase activity was measured using SBF and Tris/HCl in 23 subjects with increased cardiovascular disease risk. Precision was significantly higher using SBF than with Tris/HCl. Data from both methods do not significantly differ in samples with arylesterase activity > or = 30.6 U/L using SBF, but do differ significantly when very low activity samples (< 30.6 U/L) were included. Differences suggest that the Tris/HCl buffer gives misleading activity results, especially in very low activity samples. For the first time, results suggest that SBF can successfully be used instead of Tris/HCl in arylesterase activity determination.

Body Fluids↗
PubMed1981

Immunological characterization of plasminogen activator activities in human tissues and body fluids.

Human plasminogen activators were compared immunologically in both a double-diffusion technique and quenching experiments on the fibrinolytic activities of the activators. Antisera against HMW and LMW urokinase and an antiserum against highly purified tissue plasminogen activator from human uterus were used. It was found that uterine tissue plasminogen activator and urokinase are two immunologically distinct plasminogen activators. The occurrence of the two kinds of plasminogen activators in human tissues and body fluids was studied on the basis of the quenching of the activities by antibodies. In tissue extracts, mainly tissue plasminogen activator was found. Seminal plasma exhibited a high plasminogen activator activity, consisting of both urokinase and tissue plasminogen activator-related activators. Urine contained a small amount of tissue plasminogen activator-related activator in addition to urokinase. The low plasminogen activator activities of saliva and tears were completely attributed to activators related to tissue plasminogen activator.

Animals↗
PubMed1991

Changes in body fluid compartments during a 28-day bed rest.

The extravascular fluid responses to real or simulated space-flight are not well-documented. In this study serial isotope measurements were used to obtain measurements of the body fluid responses of 10 22-29-year-old men during 28 d of simulated microgravity (bed rest). The subjects were maintained on a controlled metabolic diet for 7 d before the study, during 14 d of ambulatory control, 28 d of horizontal bed rest, and 14 d of ambulant recovery. Fluid compartments were measured on control days 1 and 9, bed rest days 2, 14, and 28, and recovery days 7 and 14. By day 2 of bed rest, plasma volume (PV) and extra-cellular volume (ECV) decreased significantly by an average 209 and 533 ml, respectively. Red cell volume (RCV) and total body water (TBW) decreased more slowly, with average losses of 128 and 1,316 ml, respectively, after 28 d of bed rest. Early in the bed rest, TBW loss was mostly from the ECV. Thereafter, the TBW deficit was derived from the intracellular compartment, which decreased an average of 838 ml after 28 d. These results suggest losses from all fluid compartments during bed rest, with no evidence of restoration of ECV after 1-2 weeks.

Adult↗
PubMed1995

ENV-specific cytotoxic T lymphocyte responses in HIV seronegative health care workers occupationally exposed to HIV-contaminated body fluids.

Identification of the components of protective immunity are crucial for the development of effective prophylactic and therapeutic vaccine strategies. Analysis of HIV-specific responses in exposed but uninfected individuals might thus provide a unique resource to elucidate the components and correlates of protective immunity to HIV. In the present study we analyzed HIV-specific cytotoxic and helper T lymphocyte responses in health care workers (HCW) exposed to body fluids from HIV-positive individuals. HCW exposed to blood from HIV-negative individuals as well as healthy donors served as controls. Cytotoxic T lymphocyte (CTL) responses to HIV envelope (env) peptides were detected in 7/20 (35%) HCW exposed to HIV-positive blood and in none of the 20 health care workers exposed to uninfected blood or the seven healthy blood donors studied. HIV-specific CTL responses were detected only after in vitro stimulation, and were MHC class I restricted. No MHC class I restriction elements were uniformly identified among the different responders. 21/28 (75%) HCW exposed to contaminated blood responded to env as measured by IL-2 production to the peptides, in contrast to only 9/38 (24%) HCW exposed to HIV seronegative blood and 3/35 (9%) healthy blood donors. All the HIV exposed individuals were seronegative on repeated ELISA tests, and no evidence of infection was obtained by PCR analysis. These findings indicate that a single exposure to HIV can induce CTL immunity to HIV antigens, in the absence of other evidence of infection.

Accidents, Occupational↗
PubMedDate not supplied

[Risk of hepatitis B infection in Peruvian medical students following occupational exposure to blood and body fluids].

An anonymous, self-administered and voluntary survey was performed on medical students participating in the 17th International Scientific Meeting of the Latin American Federation of Scientific Societies of Medical Students, which took place in Lima, on October 2002. A total of 198 students responded, 150 of them were Peruvian. The results showed that 46.7% of these students have been exposed, at least once during the first nine months of 2002, to blood or body fluids; 29.4% of these cases were high risk expositions and none of these accidents were properly examined. Only 35.4% of the students surveyed reported having complete Hepatitis B vaccination. The high incidence of biological accidents among Peruvian students, added to the low degree of Hepatitis B vaccination and to the lack of adequate post-exposure care, places Peruvian medical students in high risk for acquiring Hepatitis B.

Accidents, Occupational↗
PubMed1996

A sensitive bioimmunoassay for thrombin-cleaved two-chain urokinase-type plasminogen activator in human body fluids.

Thrombin cleaves single-chain urokinase-type plasminogen activator (scu-PA) into a two-chain form (tcu-PA/T), which is virtually inactive in plasminogen activator assays. Little is known about the physiological importance of tcu-PA/T. To examine the occurrence of tcu-PA/T in vivo, we developed a sensitive and specific bioimmunoassay (BIA) for the assessment of tcu-PA/T in human body fluids. In this BIA, urokinase antigen was immuno-immobilized in microtiter plates and treated with cathepsin C, a specific activator of tcu-PA/T, after which plasminogen activator activity was measured. The occurrence of tcu-PA/T was examined in the plasma of 27 healthy individuals and of 17 sepsis patients, and in the synovial fluid of 16 rheumatoid arthritis patients. In addition, the concentration of urokinase antigen and scu-PA were measured in all three groups. In the plasma of the healthy individuals no measurable amounts of tcu-PA/T could be found(< detection limit of 0.2 ng/ml). In the plasma of almost all sepsis patients tcu-PA/T could be detected (median value 0.4 ng/ml). The amount of tcu-PA/T was 12% of the amount of scu-PA and accounted for about 9% of urokinase antigen. In the synovial fluid of all rheumatoid arthritis patients tcu-PA/T could be measured (median value 5.4 ng/ml) at a concentration which was twofold higher than the concentration found for scu-PA. In this group tcu-PA/T contributed to about 47% of the urokinase antigen. From these data we conclude that inactivation of scu-PA by thrombin can take place in vivo under pathological conditions which involve the production of large amounts of thrombin. This way thrombin may regulate fibrinolysis and extracellular proteolysis. The BIA for tcu-PA/T can be of use for further research on the physiological role of tcu-PA/T.

Body Fluids↗
PubMed1990

Body fluid volume regulation in health and disease: a unifying hypothesis.

In studies in experimental animals and in edematous patients, the nonosmotic release of vasopressin has been found to be consistently associated with activation of the sympathetic nervous and renin-angiotensin-aldosterone systems. Moreover, the sympathetic nervous system is known to modulate the nonosmotic release of vasopressin and activation of the renin-angiotensin-aldosterone system. These findings led to our proposal that body fluid volume regulation involves dynamic interaction between cardiac output and peripheral arterial resistance. In this context, neither total extracellular fluid volume nor total blood volume are determinants of renal sodium and water excretion. With a decrease in effective arterial blood volume (EABV) initiated by either decreased cardiac output or peripheral arterial vasodilation, the acute response involves vasoconstriction mediated by angiotensin, sympathetic mediators, and vasopressin. The renal vasoconstriction, which accompanies either decreased cardiac output or peripheral arterial vasodilation, causes a decreased distal tubular delivery of sodium and water, thus maximizing the water-retaining effect of vasopressin and impairing normal escape from the sodium-retaining effect of aldosterone. The elevated glomerular filtration rate and filtered sodium load seen in pregnant women allow increased distal sodium and water delivery despite a decrease in EABV, thus limiting edema formation during gestation.

Aldosterone↗
PubMed1990

Body fluid status on induction, reinduction and prolonged stay at high altitude of human volunteers.

Studies on adaptation to high altitude (HA) of 3500 m in the Himalayas were conducted in three phases, each including 10 normal and healthy males normally resident at sea-level. Phase I subjects had no previous experience of HA, phase II subjects after 4-6 months at HA were airlifted to sea-level and phase III subjects stayed continuously for 6 months at 3500 m. Body fluid compartments and blood gases were determined in all three groups. Plasma volume was highly elevated in the phase II subjects on reinduction to sea-level from HA. In comparison to phase I subjects, the retention of fluid in extracellular compartment was increased at HA leading to increased susceptibility to high altitude illness. Phase III subjects were hyperhydrated with decreased plasma volume and increased PO2 in comparison to the other two groups.

Acclimatization↗
PubMed1976

A gram stain for smears of blood cultures, body fluids and tissues.

A new Gram stain method for blood cultures was adapted from a method for tissue sections. This was accomplished by comparing various modifications of the latter method on positive smears prepared from a 24-hour negative blood culture seeded with Staphylococcus aureus and Escherichia coli. A blind study was then conducted using the new method and Hucker's method on 24-hour and 72-hour blood cultures as well as a limited number of other body fluids and tissues. Of the 35 positive blood cultures detected by the new method, the Hucker method failed to detect 14 positive specimens (40 per cent) upon initial examination. Ten additional cultures were negative using both stains, but were positive on subculture at three days. The 18 additional cultures positive after ten days were detected using only the Hucker stain.

Acinetobacter↗