Vascular effects of L-arginine: anything beyond a substrate for the NO-synthase?

L-arginine supplementation is hypothesized to reduce endothelial dysfunction and atherogenesis via increased biosynthesis of nitric oxide. Here we describe superoxide scavenging properties of arginine as an additional aspect which needs to be considered. Furthermore, arginine reduced copper-induced lipid peroxidation, indicating that superoxide anions essentially contribute to this process. In intact endothelial cells, L-arginine but not D-arginine diminished superoxide release and reduced cell-mediated breakdown of nitric oxide. Our data indicate that the reported vascular effects of L-arginine supplementation might involve an increased bioavailability of nitric oxide due to its superoxide scavenging properties beside a potential increased NO biosynthesis.

[Effect of chromium yeast and chromium picolinate on body composition of obese, non-diabetic patients during and after a formula diet]

The objective of this study was to assess the effects of chromium yeast and chromium picolinate on lean body mass during and after weight reduction with a very-low-calorie diet. 36 obese (BMI 33.7 +/- 5.4 kg/m2), non-diabetic patients aged 45 +/- 6 years undergoing a 8-week very-low-calorie diet followed by a 18-week maintenance period. During the whole 26 week treatment period subjects received either placebo or chromium yeast (200 micrograms/d) or chromium-picolinate (200 micrograms/d) in a double-blind manner. Body weight was measured as BMI and body composition after calculation from skinfold thickness. As a result all three groups showed comparable weight loss after 8 and 26 weeks. Lean body mass was reduced in all groups after 8 weeks. However, after 26 weeks chromium picolinate supplemented subjects showed increased lean body mass (p < 0.029) whereas the other treatment groups still had reduced lean body mass. Chromium picolinate, but not chromium yeast, is able to increase lean body mass in obese patients in the maintenance period after a very-low-calorie diet without counteracting the weight loss achieved.

Endobronchial actinomycosis

Endobronchial actinomycosis was found to be the cause of right-sided atelectasis and haemoptysis in a 57 year old man without predisposing conditions. Fibreoptic bronchoscopy revealed occlusion of the intermediate bronchus by yellow-white masses. The diagnosis was confirmed histologically and by positive Actinomyces culture from bioptic material. Prolonged antibiotic treatment resulted in complete recovery, without need for surgical resection.

Endobronchial actinomycosis

Endobronchial actinomycosis was found to be the cause of right-sided atelectasis and haemoptysis in a 57 year old man without predisposing conditions. Fibreoptic bronchoscopy revealed occlusion of the intermediate bronchus by yellow-white masses. The diagnosis was confirmed histologically and by positive Actinomyces culture from bioptic material. Prolonged antibiotic treatment resulted in complete recovery, without need for surgical resection.

The anemia of thermal injury: partial characterization of an erythroid inhibitory substance

Anemia is one of a large number of systemic changes occurring in severely burned patients and has a multifactorial etiology including hemorrhage, hemolysis, and depression of the rate of erythropoiesis. In previous studies, it was found that serum of burned humans and animals contained a substance(s) capable of interfering with red cell colony formation in vitro. Here are reported studies done in an attempt to characterize further the inhibitory activity. The molecular weight was more than 50,000 daltons by ultrafiltration. By gel filtration an inhibitory region was identified with an approximate molecular weight range of 140-290,000. Treatment of sera with proteolytic enzymes resulted in loss of activity suggesting that the inhibitory substance(s) was a protein. Ion exchange chromatography indicated that the inhibitor was an acidic protein. It is suggested that this material participates in the pathophysiology of the anemia of thermal injury by depressing red cell production.

The haematopoietic response to burning: studies in an animal model

Changes in haematopoiesis which occur in humans after burning injury may have important effects on morbidity and mortality. Because of the heterogeneity of burn patients we studied the regulation of blood cell formation which occurs in an animal using an established mouse model. Mice received a 20 per cent third degree scald injury on the back. Serial studies of a variety of haematopoietic parameters including stem cell, bone marrow and peripheral blood findings were done post burn. Although anaemia occurred frequently after injury red blood cell survival studies and examination of the stool for occult blood showed that neither haemolysis nor blood loss were primary causes of the anaemia. Bone marrow erythroid stem cells fell markedly post burn and this was associated with the development of a substance in serum capable of inhibiting red cell colony formation but not white cell colony formation of normal marrow cells. Reticulocytosis occurred but was mild and the anaemia was primarily of the aregenerative type. Partial compensation for the depressed marrow erythropoiesis occurred in the spleen with an increase in erythroid colony-forming cells and erythroblasts. Marked granulocytosis occurred in the peripheral blood and bone marrow. There was an increase in splenic granulocytic stem cells post burn. Megakaryocytosis was striking in the bone marrow and spleen and there was an increase in peripheral blood platelet count. Evidence of immune stimulation included an increase in the size of the spleen and an increase in peripheral blood and splenic lymphocytes. Correlations of many of these findings suggested that the events were not occurring at random but that the changes in haematopoiesis were linked together. We speculate that the anaemia was the result of the increase in granulopoietic and thrombopoietic effort seen post burn.

Regulation of granulopoiesis following severe thermal injury

Neutropenia often accompanies septicemia in burned patients. This paradox suggests a defect in the regulation of granulopoiesis. Colony stimulating factor (CSF) produced by the monocyte-macrophage system is an important regulator of granulocyte production. We followed serial serum CSF levels and peripheral blood leukocyte differential counts in 22 patients with greater than 30% burns. Six patients (mean burn, 58%) developed Gram-negative septicemia and died (Group I). Sixteen patients (mean burn, 38%) had no fatal septicemias (Group II). Nonsurvivors had initially low levels of CSF and developed persistent monocytopenia. Survivors, in contrast, had prompt rises in CSF and developed monocytosis. The presence of monocytopenia and low CSF levels in Group I suggests an abnormality in the stimulatory arm regulating granulopoiesis. Such a defect may play a role in the development of fatal septicemia following severe thermal injury.