(Table 3) Liver weight, blood liver parameters, and blood plasma PCB concentrations in 14 sledge dog bitches and their 14 pups in Aasiaat, west Greenland

We assessed the relationship between exposure to organohalogen polluted minke whale (Balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 Greenland sledge dogs (Canis familiaris). The prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all Chi-square: p<0.05). In case of granulomas, the frequency was significantly highest in the bitches (P generation) while the prevalence of portal fibrosis was highest in the F generation (pups) (both Chi-square: p<0.05). No significant difference between exposed and controls was found for bile acid, ALAT, and ALKP, while ASAT and LDH were significantly highest in the control group (both ANOVA: p<0.05). We therefore suggest that a daily intake of 50-200 g environmentally organohalogen polluted minke whale blubber can cause liver lesions in Greenland sledge dogs. It is reasonable to infer that other apex predators such as polar bears (Ursus maritimus) and humans may suffer from similar impacts.

Interaction of two arginine residues in lactate oxidase with the enzyme flavin: Conversion of FMN to 8-formyl-FMN

Two arginine residues, Arg-181 and Arg-268, are conserved throughout the known family of FMN-containing enzymes that catalyze the oxidation of α-hydroxyacids. In the lactate oxidase from Aerococcus viridans, these residues have been changed to lysine in two single mutations and in a double mutant form. In addition, Arg-181 has been replaced by methionine to determine the effect of removing the positive charge on the residue. The effects of these replacements on the kinetic and thermodynamic properties are reported. With all mutant forms, there are only small effects on the reactivity of the reduced flavin with oxygen. On the other hand, the efficiency of reduction of the oxidized flavin by l-lactate is greatly reduced, particularly with the R268K mutant forms. The results demonstrate the importance of the two arginine residues in the binding of substrate and its interaction with the flavin, and are consistent with a previous hypothesis that they also play a role of charge neutralization in the transition state of substrate dehydrogenation. The replacement of Arg-268 by lysine also results in a slow conversion of the 8-CH3- substituent of FMN to yield 8-formyl-FMN, still tightly bound to the enzyme, and with significantly different physical and chemical properties from those of the FMN-enzyme.

Well posedness of an integrodifferential kinetic model of Fokker-Planck type for angiogenesis.

Tumor induced angiogenesis processes including the effect of stochastic motion and branching of blood vessels can be described coupling a (nonlocal in time) integrodifferential kinetic equation of Fokker–Planck type with a diffusion equation for the tumor induced ingiogenic factor. The chemotactic force field depends on the flux of blood vessels through the angiogenic factor. We develop an existence and uniqueness theory for this system under natural assumptions on the initial data. The proof combines the construction of fundamental solutions for associated linearized problems with comparison principles, sharp estimates of the velocity integrals and compactness results for this type of kinetic and parabolic operators

Blood-respiratory and acid-base changes during extended diving in the bimodally respiring freshwater turtle Rheodytes leukops

Changes in blood-gas, acid-base, and plasma-ion status were investigated in the bimodally respiring turtle, Rheodytes leukops, during prolonged dives of up to 12 h. Given that R. leukops routinely submerges for several hours, the objective of this study was to determine whether voluntarily diving turtles remain aerobic and simultaneously avoid hypercapnic conditions over increasing dive lengths. Blood PO2, PCO2, and pH, as well as plasma concentrations of lactate, glucose, Na+, K+, Cl-, total Ca, and total Mg were determined in venous blood collected from the occipital sinus. Blood PO2 declined significantly with dive length; however, oxy-haemoglobin saturation remained greater than 30% for all R. leukops sampled. No changes were observed in blood PCO2, pH, [HCO3-], or plasma glucose, with increasing dive length. Despite repeated dives lasting more than 2 h, plasma lactate remained less than 3 mmol l(-1) for all R. leukops sampled, indicating the absence of anaerobiosis. Compensatory acid-base adjustments associated with anaerobiosis (e.g. declining [Cl-], increasing total [Ca] and [Mg]) were likewise absent, with plasma-ion concentrations remaining stable with increasing dive length. Results indicate that R. leukops utilises aquatic respiration to remain aerobic during prolonged dives, thus effectively avoiding the development of a metabolic and respiratory acidosis.

Field evaluation of a novel colorimetric method - Double-site enzyme-linked lactate dehydrogenase immunodetection assay - To determine drug susceptibilities of Plasmodium falciparum clinical isolates from northwestern Thailand

A double-site enzyme-linked lactate dehydrogenase enzyme inummodetection assay was tested against field isolates of Plasmodium falciparum for assessing in vitro drug susceptibilities to a wide range of antimalarial drugs. Its sensitivity allowed the use of parasite densities as low as 200 parasites/mul of blood. Being a nonisotopic, colorimetric assay, it lies within the capabilities of a modest laboratory at the district level.

Statistical considerations in the kinetic analysis of PET-FDG brain tumour studies

Dynamic positron emission tomography (PET) imaging can be used to track the distribution of injected radio-labelled molecules over time in vivo. This is a powerful technique, which provides researchers and clinicians the opportunity to study the status of healthy and pathological tissue by examining how it processes substances of interest. Widely used tracers include 18F-uorodeoxyglucose, an analog of glucose, which is used as the radiotracer in over ninety percent of PET scans. This radiotracer provides a way of quantifying the distribution of glucose utilisation in vivo. The interpretation of PET time-course data is complicated because the measured signal is a combination of vascular delivery and tissue retention effects. If the arterial time-course is known, the tissue time-course can typically be expressed in terms of a linear convolution between the arterial time-course and the tissue residue function. As the residue represents the amount of tracer remaining in the tissue, this can be thought of as a survival function; these functions been examined in great detail by the statistics community. Kinetic analysis of PET data is concerned with estimation of the residue and associated functionals such as ow, ux and volume of distribution. This thesis presents a Markov chain formulation of blood tissue exchange and explores how this relates to established compartmental forms. A nonparametric approach to the estimation of the residue is examined and the improvement in this model relative to compartmental model is evaluated using simulations and cross-validation techniques. The reference distribution of the test statistics, generated in comparing the models, is also studied. We explore these models further with simulated studies and an FDG-PET dataset from subjects with gliomas, which has previously been analysed with compartmental modelling. We also consider the performance of a recently proposed mixture modelling technique in this study.

Plasma D-lactate Levels in Necrotizing Enterocolitis in Premature Infants

Background: D-Lactate is normally present in the blood of humans at nanomolar concentrations due to methylglyoxal metabolism; millimolar D-lactate concentrations can arise due to excess gastrointestinal microbial production. Objectives: To examine the levels of plasma D-lactate in the necrotizing enterocolitis in premature infants. Patients and Methods: 128 premature infants were divided into control (group I, n = 69), feeding intolerance (group II, n = 42) and NEC (group III, n = 27) groups. Plasma D-lactate levels were measured at the onset of feeding intolerance or NEC and at weeks 2-3 in control infants (group I) by ELISA. Data were analyzed using descriptive statistics, non-parametric tests and Student’s t-test. Results: In groups I, II, III, median birth weights were 1845.7 ± 267.5 g, 1913.1 ± 306.5 g, and 1898.4 ± 285.3 g, median gestational ages were 34.3 ± 1.7 weeks, 33.9 ± 2.2 weeks and 35.1 ± 2.6 weeks, ages of sampling were 12.3 ± 2.9 days, 14.6 ± 3.7 days and 15.1 ± 1.8 days, respectively. The differences of median birth weights, median gestational ages and ages of sampling were not statistically significant (P > 0.05). The plasma D-lactate levels in groups I, II, III were 3.6 ± 1.9 μg/mL, 12.7 ± 8.3 μg/mL, and 35.4 ± 29.1 μg/mL, respectively, group III had higher plasma D-lactate level than groups I, II, and the difference among these groups was significant (x2 = 21.6, P < 0.01). Conclusions: Plasma D-lactate significantly increased early in NEC. Plasma D-lactate levels were associated with extensive disease in NEC infants. Therefore, it could be used as a diagnosis indicator in the early stage of NEC.

Linearity analysis and comparison study on the epoc® point-of-care blood analysis system in cardiopulmonary bypass patients

The epoc® blood analysis system (Epocal Inc., Ottawa, Ontario, Canada) is a newly developed in vitro diagnostic hand-held analyzer for testing whole blood samples at point-of-care, which provides blood gas, electrolytes, ionized calcium, glucose, lactate, and hematocrit/calculated hemoglobin rapidly. The analytical performance of the epoc® system was evaluated in a tertiary hospital, see related research article “Analytical evaluation of the epoc® point-of-care blood analysis system in cardiopulmonary bypass patients” [1]. Data presented are the linearity analysis for 9 parameters and the comparison study in 40 cardiopulmonary bypass patients on 3 epoc® meters, Instrumentation Laboratory GEM4000, Abbott iSTAT, Nova CCX, and Roche Accu-Chek Inform II and Performa glucose meters.