RESUMO
Mevalonate kinase deficiency (MKD) is caused by mutations in a key enzyme of the mevalonate-cholesterol biosynthesis pathway, leading to recurrent autoinflammatory disease characterised by enhanced release of interleukin-1ß (IL-1ß). It is currently believed that the inflammatory phenotype of MKD is triggered by temperature-sensitive loss of mevalonate kinase activity and reduced biosynthesis of isoprenoid lipids required for the prenylation of small GTPase proteins. However, previous studies have not clearly shown any change in protein prenylation in patient cells under normal conditions. With lymphoblast cell lines from two compound heterozygous MKD patients, we used a highly sensitive in vitro prenylation assay, together with quantitative mass spectrometry, to reveal a subtle accumulation of unprenylated Rab GTPases in cells cultured for 3 days or more at 40 °C compared with 37 °C. This included a 200% increase in unprenylated Rab7A, Rab14 and Rab1A. Inhibition of sterol regulatory element-binding protein (SREBP) activation by fatostatin led to more pronounced accumulation of unprenylated Rab proteins in MKD cells but not parent cells, suggesting that cultured MKD cells may partially overcome the loss of isoprenoid lipids by SREBP-mediated upregulation of enzymes required for isoprenoid biosynthesis. Furthermore, while inhibition of Rho/Rac/Rap prenylation promoted the release of IL-1ß, specific inhibition of Rab prenylation by NE10790 had no effect in human peripheral blood mononuclear cells or human THP-1 monocytic cells. These studies demonstrate for the first time that mutations in mevalonate kinase can lead to a mild, temperature-induced defect in the prenylation of small GTPases, but that loss of prenylated Rab GTPases is not the cause of enhanced IL-1ß release in MKD.
Assuntos
Deficiência de Mevalonato Quinase/enzimologia , Prenilação de Proteína , Proteínas rab de Ligação ao GTP/metabolismo , Linhagem Celular , Criança , Pré-Escolar , Feminino , Humanos , Interleucina-1beta/metabolismo , Marcação por Isótopo , Leucócitos Mononucleares/metabolismo , Masculino , Deficiência de Mevalonato Quinase/patologia , Piridinas/farmacologia , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Temperatura , Tiazóis/farmacologiaRESUMO
AIM: The aims of this study were to determine the incidence and types of haemoglobinopathies in Australian children and their distribution among ethnic groups, and to collect information on timing of diagnosis of haemoglobinopathies in Australia. METHODS: Between January 2004 and March 2006, the Australian Paediatric Surveillance Unit asked paediatricians to report all children under 15 years of age with a newly diagnosed haemoglobinopathy. A questionnaire requesting further information was forwarded to those clinicians. Carrier states such as thalassaemia minor were excluded. RESULTS: Eighty-four notifications of haemoglobinopathy were received by the Australian Paediatric Surveillance Unit, with 59 confirmed cases giving a national incidence of 0.74 per 100,000 children < 15 years of age per annum. Of 59 cases, 42 (71%) were Australian born. Twenty-nine (35.6%) children had sickle cell disease, 17 (28.8%) had Hb H disease, six (10.2%) had beta-thalassaemia major and 15 (25.4%) had compound heterozygous conditions. One child died from sickle cell disease. Of Australian born children, at least 10 mothers (23.8%) and 11 fathers (26.2%) were unaware of their carrier status pre-partum (information unavailable for 13 mothers and 17 fathers). Only 11 parents (18.6%) had risks of haemoglobinopathy discussed with them antenatally and only three cases (5.1%) were diagnosed antenatally. CONCLUSIONS: We found that a small but significant number of children with haemoglobinopathies are being born in Australia despite existing programmes of testing at-risk groups and neonatal screening. Haemoglobinopathies were also diagnosed in recent immigrants. Greater awareness of these conditions and enhancements of screening and detection programmes may be needed as the genetic diversity of the Australian population continues to develop.
Assuntos
Hemoglobinopatias/epidemiologia , Vigilância da População , Adolescente , Sudeste Asiático/etnologia , Austrália/epidemiologia , Criança , Pré-Escolar , Hemoglobinopatias/diagnóstico , Hemoglobinopatias/etnologia , Humanos , Incidência , Lactente , Programas de Rastreamento , Oriente Médio/etnologia , Inquéritos e QuestionáriosRESUMO
There is a lack of quantitative information about the generation of virus aerosols by infected subjects. The exhaled aerosols generated by coughing, talking, and breathing were sampled in 50 subjects using a novel mask, and analyzed using PCR for nine respiratory viruses. The exhaled samples from a subset of 10 subjects who were PCR positive for rhinovirus were also examined by cell culture for this virus. Of the 50 subjects, among the 33 with symptoms of upper respiratory tract infections, 21 had at least one virus detected by PCR, while amongst the 17 asymptomatic subjects, 4 had a virus detected by PCR. Overall, rhinovirus was detected in 19 subjects, influenza in 4 subjects, parainfluenza in 2 subjects, and human metapneumovirus in 1 subject. Two subjects were co-infected. Of the 25 subjects who had virus-positive nasal mucus, the same virus type was detected in 12 breathing samples, 8 talking samples, and in 2 coughing samples. In the subset of exhaled samples from 10 subjects examined by culture, infective rhinovirus was detected in 2. These data provide further evidence that breathing may be a source of respirable particles carrying infectious virus.
Assuntos
Tosse , Expiração , Respiração , Eliminação de Partículas Virais , Vírus/classificação , Vírus/isolamento & purificação , Adulto , Aerossóis , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Adulto JovemRESUMO
The objective of this prospective study was to determine the prevalence of hyperlipidemia in our pediatric renal transplant patients and to treat those with persistently elevated cholesterol and/or low-density lipoprotein (LDL) levels. All patients with a functioning renal allograft for greater than 6 months were studied (n = 18). Patients with cholesterol and/or LDL levels greater than the 95th percentile (n = 9) were commenced on an HMG-CoA reductase inhibitor, Atorvastatin and monitoring was performed for efficacy and adverse effects. Total serum cholesterol was elevated in 11 of 18 (61%) and triglyceride (TG) was elevated in 12 of 18 (67%) patients. Atorvastatin treatment was effective with a mean percentage reduction of total cholesterol of 41 +/- 10% (p < 0.01 vs. before treatment), LDL 57 +/- 7% (p < 0.01 vs. before treatment) and TG 44 +/-25% (p = 0.05 vs. before treatment). No adverse effects on allograft function or cyclosporin levels were experienced. Hyperlipidemia is a common problem and Atorvastatin is a safe and effective treatment in pediatric renal transplant recipients.