Behavior of plasminogen at the luminal surface of the normal and deendothelialized rabbit aorta in vivo and in vitro

The behavior of purified rabbit plasminogen at the luminal surface of the uninjured and deendothelialized rabbit aorta has been studied in vivo and in vitro. After intravenous injection, 125I-plasminogen associated rapidly with the endothelium (approximately 0.1 pmol/cm2 at saturation) and passed through to accumulate in the subendothelium. At two to 15 hours after injection, 11 to 15 times more radioactivity was associated with the subendothelium than with the endothelium. Removal of the endothelium by balloon catheter led to a rapid adsorption of 125I-plasminogen by the luminal surface of the vessel; saturation (9.1 pmol/cm2) was attained at ten to 20 minutes after deendothelialization. Of the adsorbed plasminogen (radioactivity), only 2% to 4% was associated with the adherent platelet monolayer. Uptake of 125I- plasminogen by the deendothelialized vessel was not significantly inhibited by epsilon-aminohexanoic acid whether injected before or after the 125I-plasminogen. No evidence of plasmin activity at the aorta surface was found from either transmission electron microscopy studies or from amidolytic assays of plasminogen-saturated deendothelialized aorta samples before or after urokinase treatment. Balloon catheter treatment in vivo, however, generated significant antiplasmin activity of the deendothelialized aorta surface. We conclude that plasmin formed in vivo is probably inactivated by the antiplasmin activity that is associated with the subendothelium.     

Expression of adhesion molecules on CD34+ cells: CD34+ L-selectin+ cells predict a rapid platelet recovery after peripheral blood stem cell transplantation

Adhesion molecules play a role in the migration of hematopoietic progenitor cells and regulation of hematopoiesis. To study whether the mobilization process is associated with changes in expression of adhesion molecules, the expression of CD31, CD44, L-selectin, sialyl Lewisx, beta 1 integrins very late antigen 4 (VLA-4) and VLA-5, and beta 2 integrins lymphocyte function-associated 1 and Mac-1 was measured on either bone marrow (BM) CD34+ cells or on peripheral blood CD34+ cells mobilized with a combination of granulocyte colony- stimulating factor (G-CSF) and chemotherapy. beta 1 integrin VLA-4 was expressed at a significantly lower concentration on peripheral blood progenitor cells than on BM CD34+ cells, procured either during steady- state hematopoiesis or at the time of leukocytapheresis. No differences in the level of expression were found for the other adhesion molecules. To obtain insight in which adhesion molecules may participate in the homing of peripheral blood stem cells (PBSCs), the number of CD34+ cells expressing these adhesion molecules present in leukocytapheresis material was quantified and correlated with hematopoietic recovery after intensive chemotherapy in 27 patients. The number of CD34+ cells in the subset defined by L-selectin expression correlated significantly better with time to platelet recovery after PBSC transplantation (r = - .86) than did the total number of CD34+ cells (r = -.55). Statistical analysis of the relationship between the number of CD34+L-selectin+ cells and platelet recovery resulted in a threshold value for rapid platelet recovery of 2.1 x 10(6) CD34+ L-selectin+ cells/kg. A rapid platelet recovery (< or = 14 days) was observed in 13 of 15 patients who received > or = 2.1 x 10(6) CD34+ L-selectin+ cells/kg (median, 11 days; range, 7 to 16 days), whereas 10 of 12 patients who received less double positive cells had a relative slow platelet recovery (median, 20 days; range, 13 to 37 days). The L-selectin+ subpopulation of CD34+ cells also correlated better with time to neutrophil recovery (r = - .70) than did the total number of reinfused CD34+ cells (r = -.51). However, this latter difference failed to reach statistical significance. This study suggests that L-selectin is involved in the homing of CD34+ cells after PBSC transplantation.     

Blood cells participate in the fibrinolytic response to tissue-type plasminogen activator

Exercise and venous occlusion stimulate fibrinolysis. In addition to increased concentrations of tissue-type plasminogen activator (tPA) and increased plasmin-mediated fibrinolysis in plasma, these stimuli produce additional cellular-phase activity in blood that is of the same magnitude as the plasma response. To determine whether tPA alone, rather than other consequences of these stimuli, is responsible for the cellular response, the in vitro effects of tPA on whole blood, plasma, and calculated cellular-phase (whole blood minus plasma) activities were determined by solid-phase radiofibrin assay on venous blood from ten normal subjects (seven men, three women). At tPA concentrations encompassing physiological and therapeutic levels (5 to 100 ng/mL; 0.7 to 14 IU/mL), increments in whole blood were consistently in excess of those in companion plasma and represented increased cellular-phase activity equivalent in magnitude to the well-known increase in plasma activity. Fibrinolytic activity produced by 10 to 20 ng tPA/mL (1.4 to 2.8 IU/mL) was consistently detected in whole blood and plasma by 60 minutes, with higher concentrations (100 ng or 14 IU tPA/mL) detectable after a five-minute assay in all subjects. Thus, tPA alone, without invoking fibrinolytic factors extraneous to blood or other effects of exercise or venous occlusion, accounts for both cellular and plasma responses to these stimuli. The considerable cellular response, the mechanism of which remains to be elucidated, may constitute a determinant of individual therapeutic responsiveness to tPA.     

On the nature of personal narratives of high quality

This investigation explores the discourse devices associated with high-quality personal narratives. The study examined normative characteristics of 11 high-quality personal narratives of a frightening experience identified (from a larger set of 72 narratives) for their effectiveness in engaging the audience. Lay ratings and an ethnographic interview with seven of the excellent storytellers further characterized the stories and validated their selection. Narratives of both African Americans and Caucasians were represented, and were similar in nature. The excellent narratives were longer, conveyed more fearful topics, and were more dramatic than average narratives. Drama was achieved through direct speech, prosodic shifts, voice changes, inclusion of multiple characters, repetition, and syntactic and semantic parallelism. Illustrative narrative excerpts are provided. This study illustrates the potential in pairing holistic and analytical approaches to narrative analysis.     

'Be active, eat right', evaluation of an overweight prevention protocol among 5-year-old children: design of a cluster randomised controlled trial

Background  

The prevalence of overweight and obesity in children has at least doubled in the past 25 years with a major impact on health. In 2005 a prevention protocol was developed applicable within Youth Health Care. This study aims to assess the effects of this protocol on prevalence of overweight and health behaviour among children.     

Preclinical evaluation of a monoclonal antibody targeting the epidermal growth factor receptor as a radioimmunodiagnostic and radioimmunotherapeutic agent

Background and purpose:

The studies described here are the first to evaluate the in vitro and in vivo properties of ¹¹¹In-CHX-A″-panitumumab for radioimmunotherapy (α- and β^--emitters) and radioimmunoimaging (single photon emission computed tomography and positron emission tomography).

Experimental approach:

Twenty-seven human carcinoma cell lines were analysed for expression of epidermal growth factor receptors by flow cytometry. Panitumumab was conjugated with CHX-A″-DTPA (diethylenetriamine-pentaacetic acid) and radiolabelled with ¹¹¹In. Immunoreactivity of the CHX-A″-DTPA-panitumumab and ¹¹¹In-CHX-A″-DTPA-panitumumab was evaluated by radioimmunoassays. Tumour targeting was determined in vivo by direct quantitation of tumour and normal tissues and by γ-scintigraphy.

Key results:

For 26 of 27 human tumour cell lines, 95% of the cells expressed epidermal growth factor receptors over a range of intensity. Immunoreactivity of panitumumab was retained after modification with CHX-A″-DTPA. Radiolabelling of the immunoconjugate with ¹¹¹In was efficient with a specific activity of 19.5 ± 8.9 mCi·mg⁻¹ obtained. Immunoreactivity and specificity of binding of the ¹¹¹In-panitumumab was shown with A431 cells. Tumour targeting by ¹¹¹In-panitumumab was demonstrated in athymic mice bearing A431, HT-29, LS-174T, SHAW or SKOV-3 s.c. xenografts with little uptake observed in normal tissues. The ¹¹¹In-panitumumab was also evaluated in non-tumour-bearing mice. Pharmacokinetic studies compared the plasma retention time of the ¹¹¹In-panitumumab in both non-tumour-bearing and A431 tumour-bearing mice. Tumour targeting was also visualized by γ-scintigraphy.

Conclusions and implications:

Panitumumab can be efficiently radiolabelled with ¹¹¹In with high labelling yields. Based on the efficiency in tumour targeting and low normal tissue uptake, panitumumab may be an effective targeting component for radioimmunodiagnostic and radioimmunotherapeutic applications.     

Genetic factors in non‐syndromic congenital heart malformations

Wessels MW, Willems PJ. Genetic factors in non‐syndromic congenital heart malformations. The genetic defect in most patients with non‐syndromic congenital heart malformations (CHM) is unknown, although more than 40 different genes have already been implicated. Only a minority of CHM seems to be due to monogenetic mutations, and the majority occurs sporadically. The multifactorial inheritance hypothesis of common diseases suggesting that the cumulative effect of multiple genetic and environmental risk factors leads to disease, might also apply for CHM. We review here the monogenic disease genes with high‐penetrance mutations, susceptibility genes with reduced‐penetrance mutations, and somatic mutations implicated in non‐syndromic CHM.     

Extended storage of red blood cells under anaerobic conditions

BACKGROUND: Red blood cells (RBC) are subject to oxidative stress by reactive oxygen species during refrigerated storage. Near-complete removal of oxygen from red cells during storage should eliminate this contributor to the red cell 'storage lesion'. The in vitro effects of storing red cells under oxygen-depleted conditions for extended periods were investigated, and these were correlated with the observed recoveries after reinfusion. STUDY DESIGN AND METHODS: Units of red cells, obtained after 'soft spin', were placed in a double volume of AS-3 additive solution and subdivided. Oxygen in the test units was depleted by repeated exposure to Ar gas (to O(2) saturation < 4%), and units were stored in anaerobic canisters for up to 15 weeks. Samples were taken weekly to monitor adenosine triphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG), cell-free haemoglobin, and vesicle production. In a parallel experiment, six units of red cells was depleted of oxygen in a similar manner, stored for 8, 9 and 10 weeks, and reinfused autologously to determine the 24 h post-transfusion recovery via (51)Cr/(99m)Tc radiolabelling. A similar study was also carried out using EAS61 additive solution, which by itself, had shown the ability to support 9-week storage, comparing biochemical profiles and in vivo recovery after aerobic vs. anaerobic storage. RESULTS: Oxygen-depleted AS-3 units had significantly elevated ATP levels compared to controls. They also had significantly lower cell free haemoglobin and vesicle production when RBCs were stored for more than 9 weeks. An average of over 75% post-transfusion survival was observed after 9 weeks of anaerobic storage with less than 0.43% haemolysis. However, no further extension of storage was achieved with EAS61 additive. CONCLUSION: Anaerobic conditions permit acceptable 9-week storage of RBCs using double-volume AS-3 additive solution. It did not synergize with the alkaline, 9-week additive, EAS61, to further lengthen the acceptable storage time. These studies indicate that anaerobic storage may allow reduction in the effect of the storage lesion, but suggest that other factors contribute to limitations of RBC storage as well.     

Maternal predictors of early breast milk output

Previous attempts to show a quantitative relationship between maternal hormone levels and early milk output have used small sample sizes and simple correlations. Women of mixed parity and similar socio-economic status and education were recruited to a study using multivariate analysis to look for these associations. Hormone levels (oestradiol, progesterone, prolactin and thyrotropin (TSH)) were determined for 91 mothers at four time points (ante- and postnatally) from finger-prick blood spots by fluoro-immunoassay. Milk output at 1 and 4 weeks was determined from 24-h test weighings. Parity was found to be the most significant factor affecting breast milk volume at 1 wk postpartum (multiparous women delivered 142 ml more milk in 24 h than primiparous women). Total time spent feeding had a strong association with breast milk volume, with increasing time having a negative effect. Multiple regression analysis, controlling for parity and time spent feeding, showed a positive association of milk output at 1 wk with antenatal progesterone and antenatal prolactin levels. At 4 wk, higher postpartum oestradiol levels had a negative association and antenatal progesterone levels a positive association with milk output. This study demonstrates that there are quantitative associations between antenatal maternal hormone levels and breast milk output in the early postnatal period.     

Conjugated linoleic acid and the control of cancer and obesity

The effects of conjugated linoleic acid (CLA) in animals are reviewed. In most of the CLA preparations that have been investigated to date for biological activity, two CLA isomers are present in about equal concentrations: cis-9,trans-11 CLA, and trans-10,cis-12 CLA. The occurrence of these isomers in foods and their production by rumen microorganisms are discussed. Potential mechanisms of action as regards the effects of CLA on cancer and body composition are reviewed, including recent evidence that body composition changes are produced by the trans-10,cis-12 CLA isomer. Evidence is presented indicating that CLA may modulate cellular response to tumor necrosis factor-alpha (TNF- alpha). The mechanistic implications of this finding are considered.