The hamster as an animal model for eastern equine encephalitis--and its use in studies of virus entrance into the brain

Eastern equine encephalitis virus (EEEV) produces the most severe human arboviral diseases in the United States, with mortality rates of 30%-70%. Vasculitis associated with microhemorrhages in the brain dominates the pathological picture in fatal human eastern equine encephalitis, and neuronal cell death is detectable during the late stage of the disease. We describe use of the golden hamster to study EEEV-induced acute vasculitis and encephalitis. In hamsters, EEEV replicates in visceral organs, produces viremia, and penetrates the brain. The pathological manifestations and antigen distribution in the brain of a hamster are similar to those described in human cases of EEEV.     

Truncation of the Shaker-like voltage-gated potassium channel, Kv1.1, causes megencephaly

The megencephaly mouse, mceph/mceph, displays dramatically increased brain volume and hypertrophic brain cells. Despite overall enlargement, the mceph/mceph brain appears structurally normal, without oedema, hydrocephaly or leukodystrophy, and with only minor astrocytosis. Furthermore, it presents striking disturbances in expression of trophic and neuromodulating factors within the hippocampus and cortex. Using a positional cloning approach we have identified the mceph mutation. We show that mceph/mceph mice carry an 11-base-pair deletion in the gene encoding the Shaker-like voltage-gated potassium channel subtype 1, Kcna1. The mutation leads to a frame shift and the predicted MCEPH protein is truncated at amino acid 230 (out of 495), terminating with six aberrant amino acids. The expression of Kcna1 mRNA is increased in the mceph/mceph brain. However, the C-terminal domains of the corresponding Kv1.1 protein are absent. The putative MCEPH protein retains only the N-terminal domains for channel assembly and may congregate nonfunctional complexes of multiple Shaker-like subunits. Indeed, whereas Kcna2 and Kcna3 mRNA expression is normal, the mceph/mceph hippocampus displays decreased amounts of Kv1.2 and Kv1.3 proteins, suggesting interactions at the protein level. We show that mceph/mceph mice have disturbed brain electrophysiology and experience recurrent behavioural seizures, in agreement with the abnormal electrical brain activity found in Shaker mutants. However, in contrast to the commonly demonstrated epilepsy-induced neurodegeneration, we find that the mceph mutation leads to seizures with a concomitant increase in brain size, without overt neural atrophy.     

Quality of life in patients with chronic alveolar hypoventilation.

Measurements of health-related quality of life (HRQL) have not been reported in patients with chronic alveolar hypoventilation (CAH) before starting home mechanical ventilation. The purpose of this study was to investigate quality of life in a population of such patients. Forty-four consecutive patients with CAH due to previous polio, scoliosis, healed pulmonary tuberculosis or neuromuscular disease answered a battery of condition specific and generic (Sickness Impact Profile, Hospital Anxiety and Depression scale, Mood Adjective Check List) self-report questionnaires. Spirometry, arterial blood gases and overnight oxygen saturation were measured. Patients with untreated CAH had significantly impaired HRQL compared to historical data from a healthy reference population. Sleep-related problems were frequent. Age, underlying disease, and standard bicarbonate correlated significantly with HRQL measures, albeit with modest levels of explained variance (8-37%). Patients with chronic alveolar hypoventilation due to neuromuscular or restrictive chest wall disorders had severely impaired health-related quality of life. Age, the underlying disease and severity of hypoventilation are each related to the health-related quality of life decrements. Health-related quality of life measurements add important information to traditional clinical observations.     

Haemophilus influenzae biofilm formation in chronic otitis media with effusion

Otitis media with effusion (OME) is a highly prevalent disease in children, but the exact pathogenesis and role of bacteria are still not well understood. This study aimed to investigate the presence of otopathogenic bacteria in the middle ear effusion (MEE) and adenoid of children with chronic OME (COME), and to investigate in vivo whether these bacteria, especially Haemophilus influenzae, are organized as a biofilm in the middle ear fluid. MEE and adenoid samples were collected from 21 patients with COME. Extensive bacterial culturing and genotyping was performed on all middle ear and adenoid samples. Fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) was used to visualize possible biofilm structures for a selection of middle ear effusion samples. 34 MEE samples were collected from 21 patients of which 64.7 % were culture positive for bacteria and 47.0 % were culture positive for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and/or Streptococcus pneumoniae. All 21 adenoid samples were culture positive for one or more of these four otopathogens. H. influenzae (35.3 %) and S. pneumoniae (76.2 %) were the most frequently cultured bacteria in the MEE and adenoid samples, respectively. The same bacterial species was found in MEE and adenoid for 84.6 % of the patients and in 81.2 % of the cases where the same species was found in more than one site it involved the same bacterial genotype. FISH and CLSM demonstrated the presence of H. influenzae specific biofilm structures in five of the eight culture positive MEEs that were tested, but in none of the two culture negative MEEs. The findings in this study indicate that the adenoid acts as a reservoir for bacteria in MEE and confirms that biofilms, in at least half of the cases consisting of H. influenzae, are indeed present in the MEE of children with COME. Biofilms may thus play a crucial role in the pathogenesis of COME, which is important in the understanding of this disease and the development of potential future treatment options.     

Block copolymers of the type poly(caprolactone)-b-poly(ethylene oxide) for the preparation and stabilization of nanoemulsions

Block copolymers poly(caprolactone)-block-poly(ethylene oxide) are promising non-ionic macromolecular surfactants for the stabilization of emulsions because they display a stronger adsorption and provide an increased long-term stability. But such amphiphilic copolymers should also allow the fabrication of the suspensions according to the emulsification process used. An evaluation of such block copolymers was done regarding the nanoprecipitation and the miniemulsion polymerization processes that both afford aqueous suspensions of nanoparticles. Both the fabrication and the long-term stability were investigated. It was found that the emulsification by means of the nanoprecipitation process was successful when the amphiphilic block copolymer was added into the organic phase. The studies on the structure-activity relationships have shown that a minimum length of the poly(ethylene oxide) block was necessary in order to ensure both the long-term colloidal stability of the suspensions and the instantaneous stability during the preparation process. The length of the hydrophobic block was a parameter of less relevance, but a minimum length was required for the copolymers to be soluble in the organic phase. The miniemulsion polymerization process using block copolymer emulsifiers could be adapted to the incorporation of large loads of vitamin E acetate used as a hydrophobe stabilizer.     

Carbamazepine protects against megencephaly and abnormal expression of BDNF and Nogo signaling components in the mceph/mceph mouse

Carbamazepine (CBZ) is a commonly used antiepileptic drug known to block voltage-gated sodium channels. Infants exposed to CBZ in utero show reduced head circumference, for reasons unknown. We investigated CBZ's effect on neural growth in megencephaly (mceph/mceph) mice lacking functional Kv1.1. Mice fed with CBZ were assessed for brain structure size, seizure behavior and expression of markers for neuronal plasticity and rescue in brain. CBZ counteracted brain overgrowth and the increased size of neurons in the mceph/mceph mouse. These effects of CBZ occurred at doses that did not fully suppress epileptic behavior. Furthermore, CBZ normalized Bdnf mRNA levels and mRNA species encoding Nogo signaling pathway proteins. In conclusion, CBZ protects efficiently against abnormal growth and abnormal expression patterns of nerve growth signaling systems in the mceph/mceph brain. These observations and the effect of CBZ in utero suggest that CBZ treatment might be advantageous in some types of human idiopathic megalencephaly.     

Arg462Gln sequence variation in the prostate-cancer-susceptibility gene RNASEL and age of onset of hereditary non-polyposis colorectal cancer: a case-control study

BACKGROUND: RNASEL is thought to be a susceptibility gene for hereditary prostate cancer and encodes the endoribonuclease RNase L, which has a role in apoptosis and is a candidate tumour-suppressor protein. A common sequence variation in RNASEL, Arg462Gln, has been associated with hereditary and sporadic prostate cancer, and the Gln variant has about three-fold reduced RNase activity in vitro. In view of the association between the age of onset of hereditary non-polyposis colorectal cancer and functionally different variants of P53, which play a key part in the apoptotic pathway, we aimed to assess whether the Arg462Gln variation of RNASEL affects the age of onset of hereditary non-polyposis colorectal cancer. METHODS: We screened 251 patients with hereditary non-polyposis colorectal cancer who were unrelated, had pathogenic germline mutations in MSH2 (n=141) or MLH1 (n=110), and had colorectal carcinoma as the first tumour, for variation at codon 462 of RNASEL and compared them with 439 healthy controls. FINDINGS: The median age of onset was 40 years (range 17-75) for patients with an Arg/Arg genotype at codon 462, 37 years (13-69) for patients with an Arg/Gln genotype, and 34 years (20-49) for those with a Gln/Gln genotype (p=0.0198). Only the RNASEL genotype had a significant effect on age of onset (p=0.0062) in an additive mode of inheritance. Pair-wise comparisons between genotype groups showed that the two homozygous groups (ie, Arg/Arg vs Gln/Gln) differed significantly in age of disease onset (mean age difference 4.8 years [SD 1.7], p=0.0044). INTERPRETATION: A sequence variation in the prostate-cancer-susceptibility gene RNASEL has a role in a different, unassociated malignant disease. Genotypes at RNASEL codon 462 are associated with age of onset of hereditary non-polyposis colorectal cancer in a dose-dependent way, and might have a role in preventive strategies for this disease.