Comparison of clinical, magnetic resonance and evoked potentials data in a case of valproic-acid-related hyperammonemic coma

Magnetic resonance (MR) multimodality evoked potentials (MEPs) and clinical findings were correlated in a 47-year-old epileptic man in whom parenteral valproic acid (VPA) therapy induced severe comatose hyperammonemic encephalopathy without biological signs of hepatotoxicity (or hepatocytic dysfunction). Although the plasma VPA level remained within a normal therapeutic range, the ammoniemia increased to a toxic peak level at 411 mol/l 24 h after symptom onset, requiring VPA therapy discontinuation. Brain MR monitoring demonstrated early cytotoxic edema evolving into delayed vasogenic edema and final brain atrophy. Concomitantly to abnormalities within the brainstem on MR images, an increase in brainstem conduction at MEPs and clinical disturbance of brainstem reflexes were observed at the initial phase of the disease course. Later, the resolution of the MR and MEPs abnormalities paralleled the clinical recovery of the reflexes.     

Pretreatment of starved rats with ornithine alpha-ketoglutarate: effects on hepatic mRNA levels and plasma concentrations of three liver-secreted proteins

OBJECTIVE: Ornithine alpha-ketoglutarate (OKG) displays anabolic properties at the hepatic level, but the mechanisms involved remain unclear. This study investigated in vivo the ability of OKG to modulate hepatic gene expression of three liver-secreted proteins: albumin, transthyretin, and retinol binding protein. METHODS: One hundred eighty rats were fed for 5 d with a balanced regimen enriched with OKG (5 g.kg(-1).d(-1)) or an isonitrogenous mixture (alanine, glycine, and serine). Hepatic mRNA levels and plasma concentrations of the three proteins studied were determined at the end of the nutrition period and after 1, 2, and 3 d of food deprivation. Results were compared by analysis of variance and Bonferroni-Dunn tests. RESULTS: At the end of the nutrition period, hepatic mRNA levels and plasma concentrations of the three proteins were not modified by OKG supplementation. However, OKG largely increased mRNA levels of albumin, transthyretin, and retinol binding protein on the first day of starvation compared with control animals (+68%, +64% and +51%, respectively; P < 0.01 versus control). OKG precociously increased albuminemia (on day 2) but had no effect on plasma concentrations of transthyretin and retinol binding protein. Neither regulation of polyamine hepatic concentration nor alteration in hepatic amino acid content seemed to be implicated in these actions. CONCLUSION: This study is the first to demonstrate that OKG regulates in vivo liver gene expression during acute malnutrition by modulating hepatic mRNA levels.     

Neoadjuvant treatment in osteosarcomas

The dismal prognosis of osteosarcoma of the limbs treated by amputation alone can be improved dramatically by including chemotherapy in an interdisciplinary regimen. Neoadjuvant chemotherapy is commonly used in order to eradicate the micrometastases and to prepare for limb-salvage surgery. To-days conservative surgery is possible in the majority of patients, including young children, and relapse-free survival attains 50-80%. High-dose methotrexate, doxorubicine, cis-platin and ifosfamide are considered the most active drugs against osteosarcoma. However, the best combination of drugs remains controversial with pending questions regarding the number of drugs to give for the preoperative phase of treatment and the value of salvage chemotherapy in poor histological responders. Furthermore long term toxicity of the drugs need to be better assessed. In order to answer these questions, treatment should be administered within the scope of prospective multi-centre trials.     

Treatment of medulloblastoma with postoperative chemotherapy alone: an SFOP prospective trial in young children

BACKGROUND: Morbidity and mortality are high in young children with medulloblastoma who receive craniospinal radiotherapy. We aimed to assess whether adjuvant treatment with protracted chemotherapy alone could replace radiotherapy. METHODS: We enrolled 79 children aged younger than 5 years who had had surgical resection of medulloblastoma onto a multicentre trial. Patients were treated with combination chemotherapy, which did not include methotrexate, for more than 16 months irrespective of the extent of disease. Early postoperative imaging defined three groups: R0M0 (no residual disease, no metastasis), R1M0 (radiological residual disease alone), and RXM+ (presence of metastases). Patients who did not relapse did not receive radiotherapy. Patients who relapsed or had disease progression received salvage treatment, which consisted of high-dose chemotherapy and stem-cell transplantation followed by local or craniospinal radiotherapy. For children classified as R0M0, the primary endpoint was 5-year overall survival and the secondary endpoint was 5-year progression-free survival. For children classified as R1M0 or RXM+, the primary endpoint was best radiological response and the secondary endpoints were 5-year overall survival and 5-year progression-free survival. Analyses were done by intention to treat. FINDINGS: Two of 15 patients classified as RXM+ and four of 17 patients classified as R1M0 had a complete radiological response. 5-year progression-free survival was 29% (95% CI 18-44) in the R0M0 group, 6% (1-27) in the R1M0 group, and 13% (4-38) in the RXM+ group. 5-year overall survival was 73% (59-84) in the R0M0 group, 41% (22-64) in the R1M0 group, and 13% (4-38) in the RXM+ group. In the R0M0 group, 5-year progression-free survival was 41% (26-58) for the 34 patients who underwent gross total resection compared with 0% for the 13 patients who had subtotal resection (relative risk 2.7 [1.3-5.6], p=0.0065). INTERPRETATION: Conventional chemotherapy alone can be used to cure children with non-metastatic medulloblastoma who have gross total resection confirmed by early radiological assessment, but is not sufficient for treatment of those with metastatic or incompletely resected medulloblastoma. Salvage treatment followed by posterior-fossa radiotherapy can effectively treat local relapses or progression.     

Characterization of In40 of Enterobacter aerogenes BM2688, a Class 1 Integron with Two New Gene Cassettes,cmlA2 and qacF

Enterobacter aerogenes BM2688, which is resistant to multiple antibiotics, and its aminoglycoside-susceptible derivative BM2688-1 were isolated from the same clinical sample. Strain BM2688 harbored plasmid pIP833, which carries a class 1 integron, In40, containing (in addition to qacEΔ1 and sul1, which are characteristic of class 1 integrons) four gene cassettes: aac(6′)-Ib, qacF, cmlA2, and oxa-9. The cmlA2 gene had 83.7% identity with the previously described nonenzymatic chloramphenicol resistance cmlA1 gene. The qacF gene conferred resistance to quaternary ammonium compounds and displayed a high degree of similarity with qacE (67.8% identity) which, however, has been found as part of a cassette with a very different 59-base element. The oxa-9 gene was not expressed due to a lack of promoter sequences. Study of the antibiotic-susceptible derivative BM2688-1 indicated that a 3,148-bp deletion between the 3′ end of the aac(6′)-Ib gene and the 3′ conserved segment of In40 was responsible for the loss of resistance. The occurrence of this DNA rearrangement, which did not involve homologous sequences, suggests that the In40 integrase could promote recombination at secondary sites.Integrons are genetic elements that can integrate, by site-specific recombination, gene cassettes, usually antibiotic resistance genes, between two conserved segments (14, 28). The 5′ conserved segment contains the int gene encoding the integrase which catalyzes site-specific recombination. In class 1 integrons, the 3′ conserved segment carries qacEΔ1, a functional deletion derivative of the qacE gene, which specifies resistance to antiseptics and disinfectants; the sul-1 gene, which confers sulfonamide resistance; and an open reading frame (ORF; ORF5) of unknown function (13, 22, 39). Integrons are often part of transposons or plasmids of various incompatibility groups. Cassettes are individual mobile units composed of a gene and of a short inverted repeat called the 59-base element, located at the 3′ end of the gene, which is recognized by the integrase IntI (4). Over the last 50 years the spread of antibiotic resistance genes occurred by integration and excision of cassettes into integrons (4, 5). Multiple cassette insertions can occur, and more than 40 distinct cassettes have been identified (28). Genes other than those conferring antibiotic resistance have been described, such as qacE, which encodes an exporter protein mediating resistance to antiseptics and disinfectants (22, 27). Cassettes are always integrated in the same orientation and are transcribed from a promoter located in the 5′ conserved segment; the cmlA1 gene, however, carries its own promoter (1, 37).Enterobacter aerogenes BM2688, which is resistant to multiple antibiotics, and its aminoglycoside-susceptible derivative BM2688-1 were isolated from the same clinical sample. Since an aac(6′)-Ib gene was detected in both strains by PCR, we attempted to determine the genetic event responsible for the loss of resistance in BM2688-1. We report on the characterization of a new integron, In40, located on a large plasmid in E. aerogenes BM2688. This element contained four cassettes including two new genes, qacF and cmlA2. Analysis of E. aerogenes BM2688-1 indicated that the loss of aminoglycoside resistance resulted from an unusual recombination event in In40.     

Antimicrobial resistance data on 16,756 Streptococcus pneumoniae isolates in 1999: A Pan-Regional Multicenter Surveillance Study in France

The rising prevalence of antibiotic-resistant Streptococcus pneumoniae is a phenomenon observed to different degrees around the world. The present national surveillance study report analyzes a total of 16,756 strains of S. pneumoniae collected across France in 1999. The overall prevalence of S. pneumoniae with decreased susceptibility to penicillin was 44%, to amoxicillin 26%, and to cefotaxime 17%. The proportion of high-level resistant strains to penicillin (MIC > 1 mg/L), amoxicillin and cefotaxime (MIC > 2 mg/L) remained low: 12.3%, 1.8%, and 0.4% respectively. Prevalence of resistance to other antibiotics was high: 53% to erythromycin, 41.7% to cotrimoxazole, 31.8% to tetracycline, and 24.6% to chloramphenicol. Prevalence of penicillin-resistant S. pneumoniae varied according to subject age and specimen source. It was higher in children (52.7%) than in adults (39.8%) and higher in strains isolated from middle ear fluid (63.6%) than from blood cultures (41.8%) in children. S. pneumoniae resistant to other antibiotics were more common in children than in adults, although figures showed geographical variations. Comparison with a previous study realized in 1997 in the same regions confirms a rising trend in the prevalence of resistant bacteria. Therefore, we conclude that prevalence of antibiotic-resistant S. pneumoniae in 1999 continued to rise in France, although strains with high-level resistance to penicillin remained stable.     

SURFACE REACTIVITY,CYTOTOXICITY, AND TRANSFORMING POTENCY OF IRON-COVERED COMPARED TO UNTREATED REFRACTORY CERAMIC FIBERS

Untreated and iron-coated refractory ceramic fibers (RCFs) 1, 3, and 4 were examined for their potential to generate free radicals and to catalyze hydrogen peroxide decomposition in cell-free assays and were compared for cytotoxic and transforming potencies in Syrian hamster embryo (SHE) cell system. Coating with a high quantity of iron increased the capability of RCFs to generate hydroxyl radicals and to catalyze the decomposition of hydrogen peroxide. In the SHE cells, the untreated RCFs had varying ability to induce inhibition of cell proliferation, cytotoxicity (as measured by the colony-forming efficiency, CE) and morphological transformation, in a concentration-dependent manner. According to cytotoxic and transforming potencies, they ranged as follows: RCF3 > RCF1 > RCF4. The lethal concentration 50 (LC50; decrease of CE to 50% of controls after 7 d of treatment) expressed per number of RCF3 and RCF1/cm 2 of culture dish was 2.5 2 10 4 and 3.7 2 10 4 , respectively, whereas RCF4 was not cytotoxic up to the highest concentration tested (23.7 2 10 4 fibers/cm 2 ). At LC50, RCF3 was 1.4-fold more transforming than RCF1, and the weakest, RCF4, induced less than 1% transformation. Iron coating of RCF1 and RCF3 markedly attenuated their cytostatic, cytotoxic, and transforming potencies without a linear concentration-transformation relationship. In contrast, iron coating of RCF4 affected slightly its low transforming potency, although the growth inhibitory effect was reduced. The observed decrease rather than increase in the cytotoxic and transforming potencies of the active samples RCF1 and RCF3 by their coating with large amounts of ferric iron suggests that it is not the quantity or any form of iron on the surface of fibers but the iron, even in trace, in a particular redox and coordinate state that might play a role in the fiber's surface reactivity with regard to the biological material. Surface chemical functions involved in the interaction with the cell could be inactivated by the deposition of a high quantity of Fe(III) on the surface of fibers. Physicochemical studies correlated to biological effects is an approach for understanding the properties of solids related to a given biological response and for elucidating the cellular and molecular mechanisms.     

Is the use of plastic capillary tubes justified for blood gases analysis?

Some clinical units, such as neonatal or maternity units, preferentially use capillary tubes when analysing blood gases. Using glass tubes is delicate and nurses must recollect blood when breaking. In order to eliminate this problem, we tested flexible, plastic capillary tubes in both the above mentionned units and in our biochemistry laboratory. Each unit, where glass tubes were habitually used, tested 200 flexible, plastic capillary tubes. In addition, the nursing staffed filled out a questionnaire concerned tube usage. Both units clearly preferred using the flexible tubes. In the laboratory, results for blood gas analyses were compared between rigid glass and flexible plastic capillary tubes for 112 patients. Concordance tests did not showed significant differences between the two tube types, except for hematocrit and total haemoglobin. A questionnaire was also presented to the lab technician, who confirmed the easier usability of plastic capillary tubes.     

Arginine-supplemented enteral nutrition in critically ill diabetic and obese rats: A dose-ranging study evaluating nutritional status and macrophage function

ObjectiveCritically ill diabetic and obese patients are at high risk of complications. Arginine availability is lowered in diabetes and in stress situations, yet arginine is necessary for immune response, mainly by its action through nitric oxide (NO). These facts argue for arginine-supplemented diets in critically ill patients. However, studies have raised concerns about possible adverse effects of such diets in intensive-care patients. We therefore analyzed the metabolic and immunologic effects of an arginine-enriched diet in stressed diabetic-obese rats.MethodsZucker Diabetic Fatty rats (fa/fa) were made endotoxemic by an intraperitoneal injection of lipopolysaccharide and then fed 4-d enteral nutrition enriched with arginine (ARG group) or a non-essential amino acid mix (NEAA group). The two groups each were subdivided into three subgroups: the ARG subgroups received 0.5 g (ARG0.5), 2 g (ARG2), and 5 g (ARG5) of arginine per kilogram daily, and the NEAA groups were made isonitrogenous with the corresponding ARG subgroups (NEAA0.5, NEAA2, and NEAA5). Plasma and urinary biomarkers were measured. Cytokine and NO production levels and inducible NO synthase and arginase protein levels were determined from peritoneal macrophages.ResultsThe survival rate was lower in the ARG5 and NEAA5 subgroups than in all the other subgroups. The nitrogen balance was higher in the ARG5 group than in the NEAA5 group. Plasma triacylglycerol levels were lower in the ARG2 group than in the NEAA2 group. Interleukin-6, tumor necrosis factor-α, and NO production in the macrophages decreased and arginase-1 was upregulated in the ARG-treated rats.ConclusionsIn this model, mortality was increased by the nitrogen burden rather than by arginine per se. Arginine improved nitrogen balance and had an anti-inflammatory action on macrophages by regulating NO production, probably through arginase-1 expression.