Comparison of dose from radiological examination for scoliosis in children among two pediatric hospitals by Monte Carlo simulation

The radiation exposures of children undergoing full spine radiography were investigated in two pediatric hospitals in Greece. Entrance surface kerma (Ka,e) was assessed by thermoluminescence dosimetry and patient's effective dose (E) was estimated by Monte Carlo simulation. All required information regarding patient age and sex, the irradiation geometry, the x-ray spectra, and other exposure parameters (tube voltage and current) were registered as well. Values of Ka,e were measured to range from 0.22 mGy to 2.12 mGy, while E was estimated to range from 0.03 mSv to 0.47 mSv. In general, all values were greater in one of the two hospitals, as higher tube currents and exposure times were used in the examinations because of the difference in radiographers' training and practice. Moreover, dose to red bone marrow was found to be between 0.01 to 0.23 mSv and dose to breast ranged between 0.02 and 1.05 mSv depending on the age, projection, and hospital. These values are comparable with literature sources.     

Sequence analysis of the coding region of human methionine synthase: relevance to hyperhomocysteinaemia in neural-tube defects and vascular disease

Elevated homocysteine (Hcy) levels are observed in two apparently unrelated diseases: neural-tube defects (NTD) and premature vascular disease. Defective human methionine synthase (MS) could result in elevated Hcy levels. We sequenced the coding region of MS in 8 hyperhomocysteinaemic patients (4 NTD patients and 4 patients with pregnancies complicated by spiral arterial disease, SAD). We identified only one mutation resulting in an amino acid substitution: an A-->G transition at bp 2756, converting an aspartic acid (D919) into a glycine (G). We screened genomic DNA for the presence of this mutation in 56 NTD patients, 69 mothers of children with NTD, 108 SAD patients and 364 controls. There was no increased prevalence of the GG and AG genotypes in NTD patients, their mothers or SAD patients. The D919G mutation does not seem to be a risk factor for NTD or vascular disease. We then examined the mean Hcy levels for each MS genotype. There was no correlation between GG- or AG-genotype and Hcy levels. The D919G mutation is thus a fairly prevalent, and probably benign polymorphism. This study, though limited, provides no evidence for a major involvement of MS in the aetiology of homocysteine-related diseases such as NTD or vascular disease.      

Changes in neutrophil surface protein composition accompany phagocytosis

Phagocytosis is a critical host defense mechanism of neutrophils. In this study, membrane protein changes occurring during phagocytosis were studied in human neutrophils using surface radiolabeling before or after phagocytosis of various target particles. Cells were labeled at the cell surface using lactoperoxidase-catalyzed iodination or neuraminidase-galactose oxidase-NaB3H4, galactose oxidase-NaB3H4, or periodate-NaB3H4 techniques. Such studies are complicated by the fact that these techniques identify many surface proteins on the phagocyte, and labeling after phagocytosis occurs often results in radiolabeling proteins of the target particle, thus making changes in cell-surface proteins more difficult to detect. Immunoprecipitation with monoclonal antibody AHN-1, which reacts with a carbohydrate present on several human neutrophil surface proteins and inhibits phagocytosis, eliminated interference caused by radiolabeled proteins of the target particle and simplified analysis by restricting the study to a limited number of proteins. AHN-1 immunoprecipitated less radiolabeled protein from neutrophils labeled after phagocytosis of particles opsonized with IgG or complement than from cells labeled before phagocytosis. Isolation of phagocytic vesicles containing opsonized emulsified paraffin oil demonstrated that three proteins of mol wt 105,000, 140,000, and 170,000 recognized by AHN-1 were internalized in the phagocytic vesicle during phagocytosis.     

Long-time quantum simulation of the primary charge separation in bacterial photosynthesis.

Accurate quantum mechanical simulations of the primary charge transfer in photosynthetic reaction centers are reported. The process is modeled by three coupled electronic states corresponding to the photoexcited chlorophyll special pair (donor), the reduced bacteriopheophytin (acceptor), and the reduced accessory chlorophyll (bridge) that interact with a dissipative medium of protein and solvent degrees of freedom. The time evolution of the excited special pair is followed over 17 ps by using a fully quantum mechanical path integral scheme. We find that a free energy of the reduced accessory chlorophyll state approximately equal to 400 cm(-1) lower than that of the excited special pair state yields state populations in agreement with experimental results on wild-type and modified reaction centers. For this energetic configuration electron transfer is a two-step process.     

Primary biliary cirrhosis presented as peripheral eosinophilia in asymptomatic women with or without elevated alkaline phosphatase

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by the destruction of biliary epithelial cells, presumably by autoimmune mechanism(s). Although lymphocytes play a pivotal role in the pathogenesis of PBC, the possible involvement of eosinophils has also been suggested. Recent studies have shown that eosinophilia possibly occurs in the peripheral blood of PBC patients. We present four cases of asymptomatic middle-aged women with moderate-to-high eosinophilia observed during random investigation. Alkaline phosphatase (ALP) was increased in two of them. As a result of clinical and laboratory evaluations the early stages of PBC were diagnosed in all the patients, as attested by the detection of high titres of anti-mitochondrial antibodies and the characteristic lesions on liver biopsies. Liver function tests and eosinophils returned within normal limits after 2 months of treatment with ursodeoxycholic acid, suggesting that its potential immunomodulatory actions may extend to eosinophils. Our report further supports the possibility that eosinophilia may occur in PBC, especially in its early stages. From the clinical point of view, we believe that PBC should be considered in the differential diagnosis of eosinophilia with an otherwise unknown origin. In particular, PBC should be suspected in a patient when other causes of eosinophilia have been excluded, irrespective of the presence or absence of symptoms, or the presence or absence of elevated ALP. In such cases further evaluation for anti-mitochondrial antibodies should be done. These observations might assist the development of future therapeutic concepts in the management of PBC, at least for patients in early stages of the disease.     

Community acquired MRSA infections in a paediatric population in Greece

We investigated the characteristics of 20 community acquired methicillin resistant Staphylococcus aureus (MRSA) strains isolated in a paediatric hospital in Athens. Eighteen of these, all isolated from skin and soft tissue infections, carried the Panton-Valentine leukocidin (PVL) determinants. They all were found resistant to fusidic acid, tetracycline and kanamycin, and displayed a PFGE pattern identical to that of the well-described ST80 CA-MRSA clone circulating in various European countries.     

Comparison between Nageotte and flow cytometric counting of residual leucocytes in freshly prepared leucocyte-reduced red blood cell components

Background

Flow cytometry (FC) and Nageotte hemocytometry represent the most widely accepted methods for counting residual white blood cells (rWBCs) in leucocyte-reduced (LR) blood components. Our aim was to study the agreement between the two methods, under real working blood bank conditions.

Hyperthyrotropinemia during iodide administration in normal children and in children born with neonatal transient hypothyroidism

The aim of the present study was to examine the effects of chronic iodide administration in pharmacological doses on thyroid function in children with a history of transient congenital hypothyroidism (TCH). We hypothesized that such children may carry a previously undisclosed intrinsic intrathyroidal defect, rendering them susceptible to TCH. We administered for this 60-65 mg iodide daily for 60 d in 13 individuals with TCH (group A), 8 of their siblings (group B), 8 healthy controls (group C), and 11 normal adults (group D). Thyroid function was evaluated by measuring serum T(3), T(4), free T(3), free T(4), TSH, and thyroglobulin concentrations and autoantibodies against thyroid peroxidase and thyroglobulin at baseline at 15, 30, and 60 d during iodide administration, and 2 months after iodide withdrawal. Hyperthyrotropinemia greater than 4.2 mU/liter but not higher than 10 mU/liter with normal thyroid hormone concentrations was observed in one of the TCH group and in two of the group B siblings. During iodide administration, hyperthyrotropinemia was observed in 8 of 13 (62%) adolescents in group A, 4 of 7 (57%) in group B, and 6 of 8 (75%) in group C. None of the 11 adults (group D) developed hyperthyrotropinemia during iodide administration. Serum T(4) and free T(4) concentrations were decreased in all groups when compared with baseline values. The magnitude of the decrease of serum T(4) was identical in all groups (0.7-0.8 microg/dl). Thyroid enlargement was observed in all subjects and was more pronounced in children. There were no cases of subclinical and/or overt hyperthyroidism. After iodine withdrawal, serum TSH decreased in all groups and returned to baseline levels, as well as the thyroid volume. In conclusion, the hypothalamic-pituitary-thyroid axis of adolescents with TCH responds to pharmacological doses of iodide similarly to that observed in normal children. The hyperthyrotropinemia observed in the adolescents exposed to iodides may reflect incipient transient hypothyroidism or simply a brisk TSH response to a small serum T(4) decrease. Whatever the mechanism, chronic use of excessive quantities of iodide should be avoided until the end of puberty.     

Oral delivery of Hyperimmune bovine serum antibodies against CS6-expressing enterotoxigenic Escherichia coli as a prophylactic against diarrhea

ABSTRACT

Background

. Oral administration of bovine antibodies active against enterotoxigenic Escherichia coli (ETEC) have demonstrated safety and efficacy against diarrhea in human challenge trials. The efficacy of bovine serum immunoglobulins (BSIgG) against recombinant colonization factor CS6 or whole cell ETEC strain B7A was assessed against challenge with the CS6-expressing B7A.