Characterization of ATP-diphosphohydrolase activities in the intima and media of the bovine aorta: evidence for a regulatory role in platelet activation in vitro.

The inner layer of the aorta contains the enzyme ATP diphosphohydrolase (ATPDase: EC 3.6.1.5) which catalyzes the sequential phosphorolysis of ATP----ADP----AMP. Two zones of the inner layer, the intima and media, were separated and both were shown to contain ATPDase activity of similar specific activity (0.08 and 0.10 U/mg protein, respectively). However, the media exhibited about 100-times more enzyme activity than the intima. Both preparations were virtually identical with respect to pH optima (7.5), migration patterns after electrophoresis under non-denaturing conditions, relative rates of ATP and ADP hydrolysis and potency to inhibit ADP-induced platelet aggregation in both human platelet-rich plasma and whole blood. The IC50 values for ADP (2 microM)-induced aggregation were 6.8 and 12.9 mU/ml in platelet-rich plasma and whole blood, respectively. Addition of ATPDase to platelets pre-aggregated with ADP resulted in a dose-dependent disaggregation in platelet-rich plasma (IC50 4.9 mU/ml), but not in whole blood. When both ATPDase (5.6-58.7 mU/ml) and ATP (0.5-10 microM) were added to platelet-rich plasma, there was an immediate dose-dependent aggregation of platelets followed by a slowly developing disaggregation. These data show that ATPDase is present in both the intima and media layers of bovine aorta and suggest a dual role for this enzyme in platelet activation. By converting ATP released from damaged cells into ADP, the enzyme could facilitate platelet aggregation at the site of vascular injury, whereas the subsequent conversion of ADP to AMP could inhibit or reverse platelet aggregation. The consequence of these activities would be to control the growth of a platelet thrombus.

Dietary exposure to benzoates (E210-E213), parabens (E214-E219), nitrites (E249-E250), nitrates (E251-E252), BHA (E320), BHT (E321) and aspartame (E951) in children less than 3 years old in France.

This study aimed to estimate the exposure to seven additives (benzoates, parabens, nitrites, nitrates, BHA, BHT and aspartame) in children aged less than 3 years old in France. A conservative approach, combining individual consumption data with maximum permitted levels, was carried out for all the additives. More refined estimates using occurrence data obtained from products' labels (collected by the French Observatory of Food Quality) were conducted for those additives that exceeded the acceptable daily intake (ADI). Information on additives' occurrence was obtained from the food labels. When the ADI was still exceeded, the exposure estimate was further refined using measured concentration data, if available. When using the maximum permitted level (MPL), the ADI was exceeded for benzoates (1.94 mg kg(-1) bw day(-1)), nitrites (0.09 mg kg(-1) bw day(-1)) and BHA (0.39 mg kg(-1) bw day(-1)) in 25%, 54% and 20% of the entire study population respectively. The main food contributors identified with this approach were current foods as these additives are not authorised in specific infant food: vegetable soups and broths for both benzoates and BHA, delicatessen and meat for nitrites. The exposure estimate was significantly reduced when using occurrence data, but in the upper-bound scenario the ADI was still exceeded significantly by the age group 13-36 months for benzoates (2%) and BHA (1%), and by the age group 7-12 months (16%) and 13-36 months (58%) for nitrites. Measured concentration data were available exclusively for nitrites and the results obtained using these data showed that the nitrites' intake was below the ADI for all the population considered in this study. These results suggest that refinement of exposure, based on the assessment of food levels, is needed to estimate the exposure of children to BHA and benzoates for which the risk of exceeding the ADI cannot be excluded when using occurrence data.

Anthropometric measurement in a protective environment.

Although specifically designed for intensive chemotherapy, the LAF room is in use in other related treatment areas, including organ transplantation, burn therapy, and hematologic conditions in which the ability to ward off infections is impaired. With the increased use of protective environments in a variety of clinical conditions, the dietitian must be able to identify and develop proper sterile techniques for anthropometry to provide the health care team with ongoing nutritional assessment for this patient population.

Nutritional management of patients with intestinal graft-versus-host disease.

Gastrointestinal Graft-Versus-Host Disease (GI GVHD) may occur following bone marrow transplantation for the treatment of acute leukemia or aplastic anemia. The resulting GI damage leads to symptoms including altered intestinal mobility, malabsorption, and protein losing enteropathy. A five-phase nutritinal regimen has been developed to supply adequate nutrient support, promote intestinal healing, reduce GI symptoms, and satisfy individual dietary preferences. The patient and family are integrally involved in the dietary planning and care. Dietary compliance is promoted through the use of nutrition education materials which explain GI GVHD and provide nutritional guidelines and their rationale.

Intravenous branched chain amino acid trial in marrow transplant recipients.

Branched chain amino acids (BCAA) improve nitrogen balance and end-organ function in surgical patients, but are untested in marrow transplant recipients. We compared nitrogen balance, urinary 3-methylhistidine-to-creatinine ratio, upper arm anthropometry, serum prealbumin, and day to peripheral engraftment in a randomized, double-blinded trial between 45% (high-leucine) and 23% BCAA intravenous solutions in 40 adult leukemia patients for 1 month following allogeneic marrow transplantation. Nutritional support, provided at approximately 30 nonprotein calories/kg and 0.21 g nitrogen/kg ideal weight, did not differ between groups. Despite greater nitrogen loss and muscle breakdown evidenced by increased 3-methylhistidine-to-creatinine ratio and loss of arm muscle area by study end in the 45% BCAA, no statistical differences were observed when nitrogen balance was compared by week and within stress level as defined by organ and infectious complications. It is likely the patients in the 45% BCAA experienced greater metabolic stress by study end. Serum prealbumin and day posttransplant to peripheral engraftment also did not differ between groups. The chances (power) of this study exceeded 85% in detecting a difference in nitrogen balance of 2.5 g during study week 1 and 4.0 g during week 2. The power during week 3 was 77% for detecting a difference of 4.0 g, and it is unlikely that the true difference exceeds this magnitude. Thus, we did not find any evidence that intravenous BCAA-enriched solutions improved nitrogen balance during the first month after marrow transplantation.

High precision measurements of carbon disulfide negative ion mobility and diffusion.

High precision measurements were made of reduced mobility, lateral and longitudinal diffusion of CS2(-) ions in 40 Torr CS2 and a 30-10 Torr CS2-CF4 gas mixture. The reduced mobility was found to be 0.4645 ± 0.0006 cm(2) atm/s V in CS2 and 0.523 ± 0.001 cm(2) atm/s V in the CS2-CF4 gas mixture at STP. The lateral diffusion temperatures for these two gases (295 ± 15 K and 297 ± 6 K) were found to be in good agreement with room temperature. By contrast longitudinal diffusion temperature was found to be slightly elevated (319 ± 10 (stat) ± 8 (sys) K and 310 ± 20 (stat) ± 6 (sys) K) though given the errors, room temperature diffusion cannot be ruled out. For lateral diffusion, significant capture distances (0.21 ± 0.07 mm and 0.15 ± 0.03 mm) were measured while for longitudinal diffusion the results were not conclusive.

Histochemical and immunocytochemical characterizations of laminated bodies in the pancreas acinar lumen.

Combined adrenalectomy and castration cause numerous morphological alterations in the exocrine pancreas of the rat. Accumulation of laminated bodies (LB) in the acinar lumen is one of these alterations. A series of classical histological stains was applied to identify the components of these structures. A positive reaction was observed with periodic acid-Schiff, Congo red, and Alcian blue (pH 2.5). The first stain reacts with neutral and some acid mucosubstances and the second with amyloid, whereas the last one reacts with sulfated and nonsulfated acid mucosubstances. The LB also responded to Luxol fast blue, indicating the presence of lipids, an observation that is in agreement with the osmiophilic properties of these structures. A more specific identification of LB components was carried out with the immunocytochemical protein A-gold technique. Presence of gamma-glutamyltranspeptidase (gamma-GT) and GP2, two glycoproteins known to be secreted by the pancreas, was tested. The gamma-GT was associated with LB whereas GP2 was found in the lumen but not associated with these structures. Amylase was undetectable when LB occupied the lumen, suggesting that the process leading to production of LB also blocks secretory activity. To determine if diet influences LB accumulation in the pancreas acinar lumen, their frequency was compared in rats fed Purina Lab Chow or a lipid-free synthetic diet. A significant increase was observed in castrated-adrenalectomized rats fed the latter diet. This increase corresponded to a pronounced reduction in the number of zymogen granules (ZG) in the acinar cell. Our results show that LB are made of lipids, neutral mucosubstances, and nonsulfated acid mucosubstances, and that hormonal (steroids) and dietary factors (lipids) influence their accumulation.

An analysis of hepatic venocclusive disease and centrilobular hepatic degeneration following bone marrow transplantation.

In order to assess the prevalence of venocclusive disease in autopsied recipients of bone marrow transplantation, we reviewed coded liver histology from 204 consecutive autopsied recipients transplanted for leukemia (142), other malignancies (5), or aplastic anemia (57). Twenty-seven patients with leukemia, 2 with carcinoma, and 3 with aplasia had venocclusive disease and survived 2-86 days post-transplant. Early lesions showed subintimal edema and hemorrhage within small central venules and centrilobular congestion with hepatocyte degeneration. Later lesions showed subtotal to complete fibrous obliteration of the central venule lumina and centrilobular sinusoidal fibrosis. Thirteen patients had a subclinical course, and 19 were symptomatic. Venocclusive disease was life-threatening or lethal in 13. Typical symptoms developed 1-3 wk post-transplant and consisted of sudden weight gain, hepatic enlargement, ascites, high bilirubin, and encephalopathy. Statistical analyses showed a significantly higher prevalence of venocclusive disease associated with transplantation for leukemia (P = 0.014), pretransplant conditioning with more rigorous chemoradiotherapy regimens (P < 0.001) and three- to fourfold increase of venocclusive disease in patients whose conditioning included dimethyl busulfan (P < 0.005). Abnormal liver tests before transplant were also more prevalent among patients with venocclusive disease. No factors predicted the clinical outcome of established venocclusive disease. Venocclusive disease showed no association with hepatic graft-versus-host disease even among prolonged cases with severe periportal hepatitis and cholestasis. Other centrilobular lesions (hepatocyte degeneration, sinusoidal fibrosis, and phlebosclerosis) were identified in 23 patients. These non-specific changes may occur with viral hepatitis, graft-versus-host disease or chemoradiotherapy effects.

Sex differences in nitrogen balance following marrow grafting for leukemia.

A sex difference in nitrogen balance was investigated in 40 adults, 21 men and 19 women, undergoing chemoradiotherapy and marrow transplantation for leukemia and receiving total parenteral nutrition. Twenty-four hour collections of urine and mixed urine-stool were analyzed for total nitrogen daily through day 14 posttransplant. Nitrogen balance, corrected for changes in blood urea nitrogen, decreased significantly over time (p less than 0.005) in both men and women, but men experienced a greater negative nitrogen balance during the time period (p less than 0.001). Mean daily nitrogen balance in men was -6.0 g for week 1 and -9.2 g for week 2, corresponding to -3.3 g and -5.6 g in women for week 1 (p less than 0.005) and 2 (p less than 0.01), respectively. The differences remained after controlling for stress level and adjusting for total calorie intakes. There were no differences in age, disease status, or nitrogen intakes per kg ideal body weight, and no effects on nitrogen balance by arm muscle area at admission, cyclosporine use, or the branched-chain amino acid content of the parenteral solution. The average rise in 3-methylhistidine excretion was 23% in men and 11% in women. These results suggest higher per kg nutrient needs in males during stress and may indicate differing metabolic responses to stress. The possibility of gender differences should be considered in research evaluating nitrogen metabolism during severe stress.