Social environment as a factor in diet-induced atherosclerosis.

Rabbits on a 2 percent cholesterol diet were individually petted, held, talked to, and played with on a regular basis. Measurements of aortic affinity for a Sudan stain, serum cholesterol levels, heart rate, and blood pressure were made at the end of the experimental period. Compared to control groups, which were given the same diet and normal laboratory animal care, the experimental groups showed more than a 60 percent reduction in the percentage of aortic surface area exhibiting sudanophilic lesions, even though serum cholesterol levels, heart rate, and blood pressure were comparable.

Ultrastructure of a bio-electrolytic methanogenic/methanotrophic granular biofilm for the complete degradation of tetrachloroethylene in contaminated groundwater.

The electrolytical methanogenic/methanotrophic coupling (eMaMoC) process was tested in a laboratory-scale single-stage reactor for the treatment of tetrachloroethene (PCE)-contaminated waters. A water electrolysis cell was placed directly in the effluent recirculation loop for the supply of both O2 and H2 to the system: H2 serving as the electron donor for both carbonate reduction into CH4 and reductive dechlorination. The concurrent presence of O2 and CH4 could be used by the methanotrophs for co-metabolically oxidising the chlorinated intermediates left over by the anaerobic transformation of PCE. At a PCE inlet of 33-52 microM and a hydraulic residence time (HRT) of 5.6 days, PCE reductive dechlorination to dichloroethene (DCE) was over 95% with a maximum DCE mineralisation of 83%. Fluorescence in situ hybridisation with 16S rRNA probes related to type I and type II methanotrophic bacteria were utilised to localise the methanotrophic communities in the anaerobic/aerobic granules. It evidenced that with operational time, along with increasing oxygenation rate, methanotrophic communities were specifically colonising onto the outermost layer of the anaerobic/aerobic granule.

Intramyocardial pressure and distribution of coronary blood flow during systole and diastole in the horse.

Transmural myocardial blood flow was measured with microspheres in systole and in diastole, along with intramyocardial pressure, in seven anaesthetised horses. Intramyocardial pressures were measured with a miniature manometer implanted in the tip of a 16-gauge needle. Peak systolic intramyocardial pressure decreased from subendocardium to subepicardium and never exceeded intraventricular pressure. Systolic blood flow decreased from epicardium to endocardium where it did not differ from zero. Diastolic blood flow increased from epicardium to subendocardium, but then decreased in the most endocardial layer to a level not different from the immediate subepicardial layer. The horse was a useful model for studying these parameters because the ventricular walls are so thick and the heart rate is so slow that injections may be made during various phases of the cardiac cycle. These results of transmural myocardial blood flow and intramyocardial pressure measured in the same animal are identical with those of others, except for the reduction in subendocardial blood flow compared with the layers just epicardial to that.

A scanning electron microscopic study of arterial endothelial cells using vascular casts.

Vascular casts were made of rabbit aortas by infusing Batson's No. 17 anatomical corrosion compound into the artery at physiological pressure. The arterial tissue was then digested with sodium hydroxide and the cast viewed by scanning electron microscopy (SEM). Outlines of the endothelial cells and their silver stained boundaries were clearly visible. Cell nuclei and fine surface detail were also discernible. In EDTA damaged arteries, injured endothelial cells and platelets could also be observed in the vascular casts.

Quantitative study of the localization of sudanophilic coeliac lesions in the White Carneau pigeon.

Polar coordinate mapping was used to determine the rate of progression of spontaneous sudanophilic coeliac lesions on the aortic wall in White Carneau pigeons. Three age groups of 5 pigeons were studied (approximately 1, 4 approximately 4 and approximately 6.5 years). Serum cholesterol was found to decrease with age (r = 0.69, P less than 0.01). Lesion area was found to increase with both age (r = 0.86, P less than 0.01) and the age--serum cholesterol product (r = 0.92, P less than 0.01). Lesions developed initially in the proximal sector (270 degrees leads to 90 degrees) with two relative maxima (approximately 20 degrees and approximately 320 degrees). Lesions then grow proximally and radially. The immediately proximal inflow region (340 degrees leads to 360 degrees) was spared in all 3 age groups. Little sudanophilic material was observed on the distal flow divider (90 degrees leads to 270 degrees) even in the oldest birds. The mode of spontaneous coeliac sudanophilic lesion development in the White Carneau pigeon is in sharp contrast to that observed both in spontaneous lesions in human infants and in experimental lesions in the hypercholesterolemic rabbit where lesion development is in the distal sector (90 degrees leads to 270 degrees).

Vascular casting. A new method for the study of the arterial endothelium.

Vascular casts of the rat aorta were made using modified Batson's No. 17 anatomical corrosion compound. The outline of the silver-stained endothelial cell boundaries were clearly visible on the cast when examined using both scanning electron and light microscopy. The physical properties of the injectate were determined. The exothermic nature of the polymerization of the injectate did not grossly damage the endothelial cells. A method was developed for recovery, without damage, of the arterial tissue surrounding the cast. The technique of vascular casting appears to be a powerful tool for the study of the arterial endothelium which avoids shrinkage artifacts and maintains 3-dimensional geometry.

Quantitative study of the rabbit aortic endothelium using vascular casts.

A quantitative study of the en face size and shape of rabbit endothelial cells from the ventral mid-thoracic and ventral infrarenal abdominal aorta has been carried out in 6 rabbits. Photomicrographs were taken from vascular casts of the rabbit aorta and the endothelial cell outlines were analyzed quantitatively using a digitizer and digital computer. The morphology of the endothelial cells was described using 8 calculated parameters (area, perimeter, length, width, angle of orientation, width:length ratio, axis intersection ratio and shape index). The endothelial cells in both locations had the same surface area (P greater than 0.30); however, the cells in the abdominal aorta were longer (P less than 0.01) and narrower (P less than 0.01) than those in the thoracic aorta. This fact is reflected by the smaller value for the shape index and width : length ratio in the abdominal aorta (P less than 0.01). Cells in both the thoracic and abdominal aorta were aligned with the flow direction.

A social relations variance partitioning of dyadic behavior.

The authors investigate the relative importance of actor and interaction partner as determinants of dyadic behavior. Using the social relations model (D. A. Kenny, 1994a; D. A. Kenny & L. La Voie, 1984), the authors estimate the variance attributable to each determinant plus the reciprocity of behavioral responses from 7 studies. The authors find evidence for moderate behavioral consistency in a person's behavior across interaction partners, little or no evidence that people consistently engender the same behavioral response from others, and preliminary evidence of unique responding to particular partners. They also consider several methodological issues concerning behavioral measurement as well as the implications of the results for the study of accuracy.

Vascular endothelial cell proliferation in culture and the influence of flow.

The influence of laminar shear stress on cell proliferation was investigated for subconfluent bovine aortic endothelial cell monolayers seeded on either glass or Thermanox. The effect of both steady and pulsatile shear stress was studied. For bovine aortic endothelial cells on Thermanox exposed to steady flow, shear stress levels greater than 15 dyne/cm2 resulted in a dose-related reduction in the rate of cell proliferation. At 90 dyne/cm2, the rate of proliferation was virtually totally arrested for 48 h, but then resumed. Pulsatile shear stress produced an exaggeration of the effect observed in response to steady shear stress. Bovine aortic endothelial cells seeded on glass, exhibited a similar but more sensitive response, with a significant reduction in growth rate observed after 24 h at shear stress levels greater than 5 dyne/cm2 and a near cessation of proliferation at 13 dyne/cm2.

Meta-accuracy among acquainted individuals: a social relations analysis of interpersonal perception and metaperception.

Meta-accuracy, knowing how others view the self, was examined using the Social Relations Model. Fifteen groups of 4-6 acquainted individuals gave self-ratings, perceptions of other group members, and estimated others' perceptions of self (metaperceptions) on the Big Five and Interesting. Individuals also rated liking and metaperceptions of liking. Trait perceptions were consensual, and self-other agreement emerged for most traits. Affect judgments were entirely relational; individuals differentiated among targets. Trait metaperceptions were dominated by perceiver variance. Individuals differed in the impression they believed others generally held about them. Affect metaperceptions, however, were relational in nature. Correlations between perceptions and metaperceptions assessed 2 types of meta-accuracy. Generalised meta-accuracy was obtained for some trait ratings. Affect judgments revealed significant dyadic meta-accuracy.

The study of rheological effects on vascular endothelial cells in culture.

A number of cell culture studies have been reported on the influence of shear stress on vascular endothelial cells. Although through such studies much has been learned about the effect of an endothelial cell's hydrodynamic environment on its structure and function, the reports indicate significant differences in methodology. Using cell shape as an indicator of differences that might result from differing methodologies, an investigation of the influence of selected variables has been carried out. The results presented indicate that not only are such variables as the level of shear stress and the duration of exposure important, but also substrate, media composition, characteristics of the cell itself, and the nature of the flow, e.g. whether it is steady state or pulsatile.

Strategies for augmenting the pentachlorophenol degradation potential of UASB anaerobic granules.

Anaerobic degradation of pentachlorophenol (PCP) is an example of a process that may benefit from enrichment or bioaugmentation. In one approach, enrichment acceleration was attempted by applying an on-line control-based selective stress strategy to a native anaerobic upflow sludge bed (UASB) system; this strategy linked PCP loading rate to methane production. As a result, the reactor biomass potential for PCP complete dechlorination reached a rate of 4 mg g(-1) volatile suspended solid (VSS) day(-1) within a period of 120 days. In another approach, a pure culture, Desulfitobacterium frappieri PCP-1, a strictly anaerobic Gram-positive bacterium, was used to augment the granular biomass of the UASB reactor. This also resulted in a specific degradation rate of 4 mg PCPg(-1) VSS day(-1); however, this potential was attained within 56 days. Fluorescent in situ hybridization (FISH) showed that the PCP-1 strain was able to rapidly attach to the granule and densely colonize the outer biofilm layer.

Comparison of the microbial population dynamics and phylogenetic characterization of a CANOXIS reactor and a UASB reactor degrading trichloroethene.

AIMS: To understand the microbial ecology underlying trichloethene (TCE) degradation in a coupled anaerobic/aerobic single stage (CANOXIS) reactor oxygenated with hydrogen peroxide (H2O2) and in an upflow anaerobic sludge bed (UASB) reactor. METHODS AND RESULTS: The molecular study of the microbial population dynamics and a phylogenetic characterization were conducted using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). In both reactors, TCE had a toxic effect on two uncultured bacterial populations whereas oxygen favoured the growth of aerobic species belonging to Rhizobiaceae and Dechloromonas. No methanotrophic bacteria were detected when targeting 16S rRNA gene with universal primers. Alternatively, pmo gene encoding the particulate methane monooxygenase of Methylomonas sp. LW21 could be detected in the coupled reactor when H2O2 was supplied at 0.7 g O2 l day(-1). CONCLUSIONS: Methylomonas sp. LW21 that could be responsible for the aerobic degradation of the TCE by-products is not among the predominant bacterial populations in the coupled reactor. It seems to have been outcompeted by heterotrophic bacteria (Rhizobiaceae and Dechloromonas sp.) for oxygen. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained show the limitations of the coupled reactor examined in this study. Further investigations should focus on the operating conditions of this reactor in order to favour the growth of the methanotrophs.

Constructing success and failure: age differences in perceptions and explanations of success and failure.

Age differences in attributions for self-reported successes and failures in both important and daily situations were examined. Sixty-one young adults (M age = 19.2), twenty-one middle-aged adults (M age = 45), and fifteen older adults (M age = 71.4) gave attributions and affects for self-chosen situations, which were classified as social or nonsocial. The attributions and affects were coded according to Blank's scheme with attributions dichotomized into internal and external, and stable and unstable. Middle-age and older adults were more likely than young adults to attribute failure to external causes and to describe more social than nonsocial situations. Consistent age differences in attributional stability were not found nor were there age differences in attributional internality for success outcomes.

Blood flow distribution within the spleen distended by perfusion at high venous pressure.

Red cell washout from the isolated, Ringer-perfused cat spleen, dilated by perfusion at elevated venous pressure (25 cm H2O), was compared with that from the relaxed spleen perfused under normal venous pressure (6 to 8 cm H2O). Cell concentrations in the outflow were measured by a Celloscope counter and plotted on semi-logarithmic paper as a function of the volume of Ringer solution perfused. Washout kinetics from relaxed spleens yielded three exponential components, the V 1/2's being 3.1, 121, and 585 ml, respectively. In the case of dilated spleens, however, only two components were found. For spleens dilated, before washout, with blood in vivo the V 1/2 value were 50 and 415 ml; for normal spleens dilated in vitro, before washout, by Ringer perfusion at high venous pressure the V 1/2 values were 60 and 439 ml. The results indicate a greatly altered intrasplenic blood flow distribution in the presence of a high splenic venous pressure; the customary fast cmponent of flow is absent, and the blood appears to be directed entirely through the pulp. This must be the situation, presumably, in congestive splenomegaly arising from portal hypertension.

Effects of pH and flow rate on the release of 'bound' red cells from the splenic pulp.

On perfusion of isolated, denervated spleens with Ringer solution, immature and abnormal red cells are released into the venous outflow much more slowly than normal mature cells, being delayed through adherence to fine structures of the red pulp (Am. J. Physiol. 231, 1665-1671 (1976)). Evidence suggested that the rate at which such cells are released from the 'bound' state might depend on local pH and fluid shear rate within the pulp. Therefore, the rate of washout for this slow component of red cells, from cat spleens, was measured as a function of pH and flow rate of the perfusate. The volume of solution (V 1/2) for 50% washout of 'bound' cells decreased as pH was lowered from 7.8 to 6.6, especially (from 97 to 18 ml/g) between 7.4 and 6.6. The percentage total red cell outflow thus represented rose from 0.06 to 0.5 as pH fell from 7.8 to 6.6. At a high perfusion rate (14-16 ml/min) the V 1/2 value was only one-half that prevailing at a lower rate (4-6 ml/min), and the percentage flow of 'bound' red cells was more than three times greater. Both acidic pH and augmented blood flow thus assist release of adherent red cells from the splenic pulp.

pH environmental of red cells in the spleen.

Intrasplenic pH in vivo was deduced from measurements on blood drained from cat spleen during contraction with the inflow occluded. The pH of blood in the red pulp is normally 7.20, but stasis or reduced flow through the pulp causes pH to fall toward 6.8. The splenic pulp contains blood of high hematocrit. To evaluate the role of buffering by the red cells themselves, intrasplenic p/ in red cell-free spleens was, therefore, estimated atering and leaving the spleen during red cell washout. At inflow pH less than 6.8 the outflow pH was raised, at inflow pH = 6.8 there was no change, b,t at inflow pH greater than 6.8 the outflow pH was lowered. These results indicate that the pH environment of red cells in the spleen results indicate that the pH environment of red cells in the spleen results from the interplay of two separate factors: i) pH-determining elements of the splenic tissue that buffer at 6.8, and ii) buffering provided by red cells passing through the pulp.

Washout kinetics of red cells and plasma from the spleen.

Radioiodinated (125I) serum albumin was injected inttravenously in cats and allowed to equilibrate in the circulation. Red cell and plasma washout from the isolated spleens were enrom the isolated spleens were then compared during perfusion with oxygenated Ringer solution, the respective concentrations in the outflow being measured by celloscope and scintillation counters. Washout kinetics yielded three exponential components for cells (perfusate volumes for 50% washout (V1/2) being 0.067, 4.70, and 97 ml/g spleen) but only two for plasm (V1/2, 0.14 and 2.40 ml/g). There is no plasma counterpart to the slowly released cells, i.e., they do not represent a separate vascular space. This is an accord with a previous view that these are immature cells, delayed through adherence to fine structures of the red pulp. Compartment analysis indicates that the plasma and two remaining cell components represent washout from two separate vascular spaces, containing 0.09 ml/g blood at arterial hematocrit 37% and 0.42 ml/g blood at hematocrit 75%, perfused by 0.9 and 0.1 of the arterial inflow respectively. Evidence suggests these spaces are i) blood vessels, and ii) red pulp.