Cyclohexane transformation during water chlorination

Cyclohexane transformation was studied during water chlorination. Three mechanisms of cyclohexane transformation in the presence of chlorine were determined. Over 70 reaction products were identified. Five of them have mutagenic activity.     

Enteropathogenicity markers in Escherichia coli isolated from infants with acute diarrhoea and healthy controls in Rio de Janeiro, Brazil

Faeces from urban children < 2 years old with acute diarrhoeal illness and from non-diarrhoeal infants (controls) were examined for Escherichia coli and other enteropathogens. A total of 990 E. coli isolates from 100 patients and 50 controls was tested for enteropathogenic E. coli (EPEC) serotype (O:H), adherence to HEp-2 cells after incubation for 3 and 6 h, fluorescent actin staining (FAS), DNA hybridisation with EAF, eaeA, STh, STp and EAggEC probes and production of heat-labile enterotoxin (LT) and verocytotoxin (VT) with Y1 and Vero cells. EPEC were the most prevalent enteropathogens in patients (32.7%; and 14% in controls). Enteroinvasive E. coli (EIEC) and Vero cytotoxin-producing E. coli (VTEC) were not detected. The rate of isolation of enterotoxigenic E. coli (ETEC) was identical in both groups. Among the EPEC isolates the prevalent serotypes were O111:H2, O55:NM and O119:H6. Localised adherence (LA) was found significantly more frequently in isolates from patients (19.6%) than controls (2.1%). All LA-positive EPEC isolates were FAS+ and eaeA+, but only 75.2% of them hybridised with the EAF probe. Diffusely adhering E. coli (DAEC) and enteroaggregative E. coli (EAggEC) were found with equal frequency in patients and controls. Twenty-seven E. coli isolates were negative for EAF but positive for eaeA and FAS and produced LA in 6-h adherence tests. These EAF-/eaeA+ strains were the only putative enteropathogen identified in seven patients and were not found in controls. The ability of these strains to elicit ultrastructural cell alterations and cell-signalling events was evaluated in Caco-2 cells (human colon carcinoma cell line) by the gentamicin invasion assay and by transmission electron microscopy. The numbers of intracellular bacteria in cell invasion tests varied from 0.4% to 1.6% of the cell-associated bacteria after a 6-h incubation period. Tyrosine phosphorylation of host cell proteins was assessed in HEp-2 cells by immunofluorescence microscopy and all strains gave positive results. EAF-/eaeA+ E. coli strains express most of the virulence properties found among true EPEC strains and can be a relevant cause of infant diarrhoea in developing countries.     

Dominant optic atrophy: exclusion and fine genetic mapping of the candidate gene, HRY

The treatment of infants and children with short bowel syndrome aims at restoring the intestinal continuity and at improving the physiological process of gut adaptation. Mucosal hyperplasia allows the remaining gut to ensure an adequate digestion and an absorption process leading to intestinal autonomy. During the period of adaptation, appropriate parenteral and/or enteral feeding must be directed at maintaining an optimal nutritional status. Delay of intestinal autonomy depends on the characteristics of the residual intestine: length, presence of the ileocecal valve and colon, and motor function. Bacterial overgrowth compromises intestinal adaptation and increases the risk of liver disorders. Few patients will remain long-term dependent on parenteral nutrition. All approaches aimed at achieving intestinal autonomy should be tried: use of trophic factors, intestinal tapering, and lengthening. In a few residual patients, permanent intestinal failure or extreme short bowel syndrome require intestinal transplantation.     

Three hypotonic neonates with hypertrophic cardiomyopathy: Pompe's disease

Three neonatal patients, one girl and two boys, presented with infantile Pompe's disease. A generalized hypotonia with decreased tendon reflexes and heart failure due to hypertrophic cardiomyopathy dominated the clinical picture in all three; these symptoms are uniformly and characteristically present. This autosomal recessive glycogen storage disease is caused by a deficiency of lysosomal alpha-glucosidase. The diagnosis, suspected on the basis of the characteristic clinical picture and the results of simple laboratory tests, is made by measurement of the enzymatic activity or DNA analysis. Most patients die in their first year of life, no treatment being available.     

Rugby injuries to the cervical spine and spinal cord: a 10-year review

A 10-year review (1987-1996) of injuries sustained to the spine and spinal cord in rugby players with resultant paralysis has been undertaken. This article reviews that the incidence of serious rugby spine and spinal cord injuries in South Africa has increased over the 10-year period reviewed, despite stringent new rules instituted in an attempt to decrease the incidence of these injuries. The mechanisms of injury, as previously reported, remain the same as well as the phases of game responsible for injury of the tight scrum, tackle, rucks, and mauls. Two new observations are reported: the first is related to the occurrence of spinal cord concussion with transient paralysis, and the second is related to the increased incidence of osteoarthritis of the cervical spine in rugby players.     

Discrimination of mammalian growth hormones by peptide-mass mapping

Recognition by the legal authorities that growth hormones (GHs) may be abused to improve sporting performance and/or physique has led to the implementation of controls that make it an offence to produce, supply, possess or import and export GHs, with intent to supply, without the authority to do so. A method is described for the discriminatory analysis of human, equine, porcine and bovine GHs for forensic purposes. Peptide-mass mapping by matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry following tryptic digestion gave sequence coverages of 97.4%, 93.7%, 94.2% and 90.6% for human, equine, porcine and bovine GHs respectively. The tryptic-mass maps generated were sufficient to discriminate between the four hormones analysed and thus provide unambiguous identification of each individual GH. Identification of the N-terminal peptides of recombinant equine and porcine GHs, which possess additional methionine residues, within the tryptic-mass maps may provide the basis of a test to indicate exogeneous administration rather than endogenous secretion of GH in performance dogs and horses.     

The influence of hypoxia on the cytotoxicity of concomitant KW-2149 and ionizing irradiation in Chinese hamster fibroblasts

7-N-((2-((2-(gamma-L-glutamylamino)ethyl)dithio)ethyl))-mitomycin C (KW-2149) is a newly synthesized water-soluble mitomycin C (MMC) analog. Preclinical testing showed an interesting activity profile and a superior hematological tolerance in murine models. The aim of this study was to investigate the interaction of this compound with ionizing radiation, both under normoxic and hypoxic conditions, in Chinese hamster fibroblasts (V79). V79 cells were irradiated both under normoxic conditions and after a 1 h period of hypoxia. Paired irradiation dose-response curves confirmed the significance of radioresistance under hypoxia with an oxygen enhancement ratio of approximately 3. In contrast to MMC, KW-2149 showed no increased cytotoxic effect on hypoxic V79 cells. The cytotoxic effect of KW-2149 increased with increasing concentration, irrespective of the ambient oxygen pressure. When KW-2149 was combined with irradiation under hypoxic conditions, cytotoxicity was significantly enhanced under these conditions. The difference in survival between normoxic and hypoxic conditions was statistically significant (p < 0.004). These data suggest a radiosensitizing effect of KW-2149, more pronounced under hypoxic conditions. This effect increases with radiation dose. It also corroborates earlier suggestions of a different mode of action of KW-2149 as compared to MMC.