Pyrrolnitrin from Burkholderia cepacia: antibiotic activity against fungi and novel activities against streptomycetes.

A bacterial strain identified as Burkholderia cepacia NB-1 was isolated from water ponds in the botanical garden in Tübingen, Germany, and was found to produce a broad spectrum phenylpyrrole antimicrobial substance active against filamentous fungi, yeasts and Gram-positive bacteria. In batch culture containing glycerol and L-glutamic acid, the isolate NB-1 produced the antibiotic optimally late in the growth phase and accumulated a main portion in their cells. Isolation and purification of the antibiotic from Burkholderia (Pseudomonas) cepacia NB-1 by acetone extraction, gel filtration on Sephadex LH-20 and preparative HPLC yielded 0.54 mg l-1 of a pure substance. Spectroscopic data (HPLC, MS and NMR) confirmed that the compound was pyrrolnitrin [3-chloro-4-(2'-nitro-3'-chloro-phenyl) pyrrole]. Pyrrolnitrin has an inhibitory effect on the electron transport system, as demonstrated by isolated mitochondria from Neurospora crassa 74 A. This inhibition was relieved by N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD), indicating that pyrrolnitrin blocked the electron transfer between the dehydrogenases and the cytochrome components of the respiratory chain. Among Gram-positive bacteria, pyrrolnitrin was most active against certain Streptomyces species, especially S. antibioticus, which has not previously been described in the literature. In the presence of pyrrolnitrin, aerial mycelium and spore formation of Strep. antibioticus was suppressed, although growth continued via substrate mycelium. The new findings of inhibition of streptomycetes and their secondary metabolism by pyrrolnitrin may contribute to the fact that Pseudomonas species predominate in soil and compete even with antibiotic-producing Streptomyces.

Bone mineral density in prepubertal children with beta-thalassemia: correlation with growth and hormonal data.

Patients with beta-thalassemia major (beta-thalassemia) frequently have bone disorders of multifactorial etiology. We attempted to analyze the relationship between the bone mineral density ([BMD] measured by dual-photon absorptiometry) and auxanologic parameters, degree of siderosis, function of the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF-binding protein-3 (IGFBP3) axis, calcium-phosphate balance, parathyroid hormone (PTH), and cytokines (interleukin-1beta [IL-1] and tumor necrosis factor-alpha [TNF-alpha]) in 30 prepubertal children with beta-thalassemia major and 15 age-matched children with constitutional short stature (CSS), who have normal glucose tolerance and thyroid function. Children with beta-thalassemia had a significantly decreased BMD and mean BMD% for age and sex (0.75+/-0.24 g/cm2 and 71%+/-10%, respectively) versus children with CSS (1.06+/-0.3 g/cm2 and 92%+/-7%, respectively). Thalassemic patients had significantly lower circulating concentrations of IGF-I and IGFBP3 (49+/-21 ng/mL and 1.2+/-0.25 mg/L, respectively) compared with control children (153+/-42 ng/mL and 2.1+/-0.37 mg/L, respectively). The GH response to provocation by clonidine and glucagon was defective (peak GH < 7 microg/L) in 12 of the 30 thalassemic children. Serum concentrations of IL-1beta and TNF-alpha did not differ among the two study groups. Hypocalcemia was detected in five of the 30 thalassemic patients: hypoparathyroidism was diagnosed in two of the five and rickets in the other three. BMD was highly correlated with the circulating concentrations of IGF-I and IGFBP3, as well as with the auxanologic parameters (age, weight, height, height standard deviation score [HSDS], and body mass index [BMI]). It is suggested that increasing the circulating IGF-I concentration through aggressive nutritional therapy and/or GH/IGF-I therapy with supplementation with vitamin D and/or calcium might improve bone growth and mineralization and prevent the development of osteoporosis and consequent fractures in these patients. Such therapy requires blinded controlled trials.

GH response to provocation and circulating IGF-I and IGF-binding protein-3 concentrations, the IGF-I generation test and clinical response to GH therapy in children with beta-thalassaemia.

The causes of growth retardation of children with thalassaemia major are multifactorial. We studied the GH response to provocation by clonidine and glucagon, measured the circulating concentrations of insulin, IGF-I, IGF-binding protein-3 (IGFBP-3) and ferritin, and evaluated IGF-I generation after a single dose of GH (0.1 mg/kg per dose) in 15 prepubertal patients with thalassaemia, 15 age-matched children with constitutional short stature (CSS) (height standard deviation score less than -2, with normal GH response to provocation) and 11 children with isolated GH deficiency (GHD). Children with thalassaemia had significantly lower peak GH response to provocation by clonidine and glucagon (6.2 +/- 2.3 and 6.8 +/- 2.1 microg/l respectively) than the CSS group (18.6 +/- 2.7 and 16.7 +/- 3.7 microg/l respectively). They had significantly decreased circulating concentrations of IGF-I and IGFBP-3 (47.5 +/- 19 ng/ml and 1.2 +/- 0.27 mg/l respectively) compared with those with CSS (153 +/- 42 ng/ml and 2.06 +/- 0.37 mg/l respectively), but the IGF-I and IGFBP-3 concentrations were not different from those with GHD (56 +/- 25 ng/ml and 1.1 +/- 0.32 mg/l respectively). These data demonstrate that the GH-IGF-I-IGFBP-3 axis in thalassaemic children is defective. Serum ferritin concentration correlated significantly with GH peak response to provocation (r = -0.36, P < 0.05) and circulating IGF-I (r = -0.47, P < 0.01) and IGFBP-3 (r = -0.42, P < 0.01) concentrations. In the IGF-I generation test, after GH injection, the thalassaemic children had significantly lower IGF-I and IGFBP-3 levels 86.7 +/- 11.2 ng/ml and 2.05 +/- 0.51 mg/l respectively) than those in the CSS group (226 +/- 45.4 ng/ml and 2.8 +/- 0.43 mg/l respectively). The IGF-I response was significantly higher in children with GHD (158 +/- 50 ng/ml) than in thalassaemic children. Six short (height standard deviation score less than -2) thalassaemic children who had defective GH response to provocation (< 10 microg/l), all the children with GHD and eight short normal children (CSS) were treated for 1 year with human GH (18 units/m2 per week divided into daily s.c. doses). After 1 year of GH therapy there was a marked acceleration of growth velocity in both thalassaemic children (from 3.8 +/- 0.6 cm/year to 7.2 +/- 0.8 cm/year) and controls. However, the linear acceleration of growth velocity on GH therapy was significantly slower in thalassaemic children (3.3 +/- 0.3 cm/year increment) compared with those with CSS (5.3 +/- 0.4 cm/year increment) and GHD (6.9 +/- 1.2 cm/year increment) (P < 0.05). Their circulating IGF-I concentration (105 +/- 36 ng/ml) was significantly lower than those for CSS (246 +/- 58 ng/ml) and GHD (189 +/- 52 ng/ml) after 1 year of GH therapy. These data prove that some children with beta-thalassaemia major have a defective GH-IGF-I-IGFBP-3 axis and suggest the presence of partial resistance to GH.

Growth hormone secretion and circulating insulin-like growth factor-I (IGF-I) and IGF binding protein-3 concentrations in children with sickle cell disease.

Impaired growth involving both height and weight accompanying sickle cell disease (SCD) poses diagnostic and therapeutic problems. We undertook this study to test the hypothesis that this impaired growth is associated with abnormalities of the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF binding protein-3 (IGFBP-3) axis in 21 children with SCD and that SCD is associated with GH resistance. Nine of 21 children with SCD had a defective GH response to both clonidine and glucagon provocation (peak < 10 micrograms/L); these children differed from the 12 others in having slower linear growth velocity (GV and GVSDS), lower circulating concentrations of IGF-I and IGFBP-3, and either partial or complete empty sellae in computed tomographic scans of the hypothalamic-pituitary area. In this group of patients with SCD, it appears that defective GH secretion and consequent low IGF-I production are the major etiological factors causing the slow growth. The two groups with SCD did not differ significantly in dietary intake, body mass index (BMI), midarm circumferences, skinfold thickness, serum albumin concentration, or intestinal absorption of D-xylose. A single injection of GH produced a smaller increase in circulating IGF-I in children with SCD with or without defective GH secretion versus 10 age-matched children with idiopathic short stature (ISS) and 11 children with isolated GH deficiency (GHD), suggesting partial GH resistance in the SCD group. The presence of defective GH secretion, decreased IGF-I synthesis, and partial resistance to GH in short children with SCD suggests that treatment with IGF-I may be superior to GH therapy for improving growth.

Insulin and glucagon responses to provocation with glucose and arginine in prepubertal children with thalassemia major before and after long-term blood transfusion.

Hypertransfusion therapy has dramatically increased the duration and quality of life in patients with B-thalassemia major; however, it leads to chronic iron overload, and is frequently complicated by the development of diabetes mellitus or impaired glucose tolerance. To determine the early effect of iron overload on the endocrine pancreatic function, we studied glucose, insulin, and glucagon responses to oral load of glucose and to arginine provocation in 15 children with B-thalassemia major, before and after (3.1 +/- 0.6 years) high-transfusion and iron chelation and compared them with 15 age matched normal controls. In addition, we evaluated growth hormone (GH) responses to oral clonidine and measured the circulating insulin-like growth factor-I concentration in thalassemic children on long-term transfusion and controls. After long-term high-transfusion, thalassemic children had significantly decreased serum insulin concentrations and low insulin/glucose ratios at 60 and 120 min after an oral glucose load (1.75 g/kg) in comparison with values before therapy and those for controls. None of the thalassemic children had glucose intolerance after this period of frequent blood transfusion; however, their serum glucose levels at 60 and 120 min after the oral glucose load were significantly higher compared to control children. Thirty minutes after starting arginine infusion, serum insulin concentration was significantly lower in thalassemic children compared to before therapy. Basal and arginine-stimulated glucagon secretions were significantly elevated in thalassemic children on long-term blood transfusion with significantly low serum insulin/glucagon ratios. In addition, the high basal serum glucagon concentrations were not suppressed after the oral glucose load. Despite hyperglucagonaemia in all thalassemic children, their blood glucose dropped appropriately below 50 per cent of the fasting glucose level after an intravenous insulin dose (0.1 U/kg) ruling out any significant insulin-resistance. GH responses to clonidine provocation were subnormal in thalassemic children after long-term blood transfusion compared to controls. In summary, thalassemic children on long-term blood transfusion and iron chelation have progressive and early loss of B-cell mass, manifested by decreased insulin release in response to secretagogues, before the development of significant insulin resistance or impairment of glucose tolerance.

Circulating growth hormone (GH), insulin-like growth factor-I (IGF-I) and free thyroxine, GH response to clonidine provocation and CT scanning of the hypothalamic-pituitary area in children with sickle cell disease.

Serum growth hormone (GH), cortisol, free thyroxine (FT4), thyroid-stimulating hormone (TSH), and insulin like growth factor I (IGF-I) concentrations were measured in 15 children with sickle cell disease (SCD) together with their heights < 5th percentile for age and gender, and in 15 healthy age-matched children who had normal variant short stature (NVSS). GH response to an oral dose of clonidine (0.15 mg/m2) and cortisol response to ACTH stimulation were determined in the two groups. Children with SCD had significantly lower serum concentrations of IGF-I and decreased GH response to stimulation. Eight out of the 15 children with SCD did not mount an appropriate GH response to clonidine provocation (> 10 micrograms/l). CT scanning of the hypothalamic-pituitary area in those eight children with SCD revealed a partial or complete empty sella in all of them. It appears that defective GH release, and consequently low IGF-I production and slow growth velocity in children with SCD might be secondary to hypoxic-vascular insults to their hypothalamic-pituitary axis during one or more of the sickling episodes.

Acute urticaria and hepatitis complicating high-dose methotrexate therapy.

We report an unusual case of anaphylaxis and hepatitic dysfunction in a child with the administration of the twenty-third course of high-dose methotrexate. The latter had been used as an adjuvant to prevent pulmonary metastases and the prior 22 courses had been well tolerated. An attempt to reinstate methotrexate after the twenty-third course was again followed by a similar reaction.

[Antigenic response against PPD and antigen 60 in tubercular patients: single antigen versus the combined test]. / Respuesta antigénica frente al PPD y al antígeno 60 en pacientes tuberculosos: antígeno único frente a test combinado.

We analyze serum samples from 70 patients with pulmonary tuberculosis and 50 healthy individuals. The antigenic activity (IgG) against protein purified antigen (PPD) and antigen 60 (A60) from M. tuberculosis. Thirteen patients were also HIV infected, and three patients had AIDS defined by the presence of disseminated tuberculosis. The test using antigen alone showed a 77% sensitivity and 74% specificity when PPD is used. When A60 was used, both values improved (81% sensitivity, 94% specificity). The use of a combined test (PPD and A60) improves the sensitivity (89%) but reduces the specificity (82%). The HIV infected patients showed similar responses to those of other patients. The combined use of different antigens might be useful for diagnosing tuberculosis.

Effects of chronic alcohol consumption and iron deficiency on maternal folate status and reproductive outcome in mice.

The influence of chronic alcohol consumption with or without iron deficiency on reproductive performance and folate status was studied. Female CBA/J mice were fed isocaloric liquid diets prior to and during pregnancy. A 2 X 2 factorial design was employed with ethanol-derived calories (EDC) and iron (Fe) as dietary variables. Groups received 0% EDC and 30 ppm Fe (CA); 0% EDC and 2 ppm Fe (CD); 20% EDC and 30 ppm Fe (EA); and 20% EDC and 2 ppm Fe (ED). Animals were killed on day 18 of gestation. Mean body weights were reduced in CD, EA and ED groups, while daily caloric intakes reduced only in CD and ED groups. Maternal values for hemoglobin, transferrin saturation and red cell folates decreased with iron deficiency and/or 20% EDC; hematocrit, serum iron and serum folates decreased only with iron deficiency. Blood ethanol levels were similar in EA and ED groups. Maternal liver total lipids and alcohol dehydrogenase activity increased only with 20% EDC, while dihydrofolate reductase activity decreased with iron deficiency and/or 20% EDC. Iron deficiency and/or 20% EDC adversely affected gestational performances in mice as indicated by increased resorptions and decreased percentages of live fetuses/litters and live fetal weights. Data indicate that iron deficiency and/or chronic ethanol consumption induce adverse effects on maternal reproductive performance of CBA/J mice possibly via alteration of folate metabolism.

Effects of massive intestinal resection and splenectomy on portal pressure and thoracic duct lymph. An experimental study.

The effect of massive intestinal resection (MIR) alone and when combined with splenectomy, on portal pressure and thoracic duct lymph (TDL) flow, and protein content, was experimentally studied in a series of 12 dogs with created presinusoidal portal obstruction. MIR was associated with a significant drop in the portal pressure and TDL flow, and significant increase in TDL protein content. When splenectomy was added, more reduction of the portal pressure and TDL flow was obtained. The significance of these findings is discussed in relation to the hemo- and lymphodynamic changes in presinusoidal portal obstruction.