The molecular basis of Sanfilippo syndrome type B.

The Sanfilippo syndrome type B is a lysosomal storage disorder caused by deficiency of alpha-N-acetylglucosaminidase; it is characterized by profound mental deterioration in childhood and death in the second decade. For understanding the molecular genetics of the disease and for future development of DNA-based therapy, we have cloned the cDNA and gene encoding alpha-N-acetylglucosaminidase. Cloning started with purification of the bovine enzyme and use of a conserved oligonucleotide sequence to probe a human cDNA library. The cDNA sequence was found to encode a protein of 743 amino acids, with a 20- to 23-aa signal peptide immediately preceding the amino terminus of the tissue enzyme and with six potential N-glycosylation sites. The 8.5-kb gene (NAGLU), interrupted by 5 introns, was localized to the 5'-flanking sequence of a known gene, EDH17B, on chromosome 17q21. Five mutations were identified in cells of patients with Sanfilippo syndrome type B: 503del10, R297X, R626X, R643H, and R674H. The occurrence of a frameshift and a nonsense mutation in homozygous form confirms the identity of the NAGLU gene.

Distribution of endogenous type B and type D sheep retrovirus sequences in ungulates and other mammals.

The jaagsiekte sheep retrovirus (JSRV), which appears to be a type B/D retrovirus chimera, has been incriminated as the cause of ovine pulmonary carcinoma. Recent studies suggest that the sequences related to this virus are found in the genomes of normal sheep and goats. To learn whether there are breeds of sheep that lack the endogenous viral sequences and to study their distribution among other groups of mammals, we surveyed several domestic sheep and goat breeds, other ungulates, and various mammal groups for sequences related to JSRV. Probes prepared from the envelope (SU) region of JSRV and the capsid (CA) region of a Peruvian type D virus related to JSRV were used in Southern blot hybridization with genomic DNA followed by low- and high-stringency washes. Fifteen to 20 CA and SU bands were found in all members of the 13 breeds of domestic sheep and 6 breeds of goats tested. There were similar findings in 6 wild Ovis and Capra genera. Within 22 other genera of Bovidae including domestic cattle, and 7 other families of Artiodactyla including Cervidae, there were usually a few CA or SU bands at low stringency and rare bands at high stringency. Among 16 phylogenetically distant genera, there were generally fewer bands hybridizing with either probe. These results reveal wide-spread phylogenetic distribution of endogenous type B and type D retroviral sequences related to JSRV among mammals and argue for further investigation of their potential role in disease.

Null mutation of endothelin receptor type B gene in spotting lethal rats causes aganglionic megacolon and white coat color.

Mutations in the gene encoding the endothelin receptor type B (EDNRB) produce congenital aganglionic megacolon and pigment abnormalities in mice and humans. Here we report a naturally occurring null mutation of the EDNRB gene in spotting lethal (sl) rats, which exhibit aganglionic megacolon associated with white coat color. We found a 301-bp deletion spanning the exon 1-intron 1 junction of the EDNRB gene in sl rats. A restriction fragment length polymorphism caused by this deletion perfectly cosegregates with the sl phenotype. The deletion leads to production of an aberrantly spliced EDNRB mRNA that lacks the coding sequence for the first and second putative transmembrane domains of the G-protein-coupled receptor. Radioligand binding assays revealed undetectable levels of functional EDNRB in tissues from homozygous sl/sl rats. We conclude that EDNRB plays an essential role in the normal development of two neural crest-derived cell lineages, epidermal melanocytes and enteric neurons, in three mammalian species--humans, mice, and rats. The EDNRB-deficient rat may also prove valuable in defining the postnatal physiologic role of this receptor.

Receptor usage and differential downregulation of CD46 by measles virus wild-type and vaccine strains.

Recently, two cell surface molecules, CD46 and moesin, have been found to be functionally associated with measles virus (MV) infectivity of cells. We investigated the receptor usage of MV wild-type, subacute sclerosing panencephalitis, and vaccine strains and their effect on the down-regulation of CD46 after infection. We found that the infection of human cell lines with all 19 MV strains tested was inhibitable with antibodies against CD46. In contrast, not all strains of MV led to the downregulation of CD46 following infection. The group of CD46 non-downregulating strains comprised four lymphotropic wild-type isolates designated AB, DF, DL, and WTF. Since the downregulation of CD46 is caused by interaction with newly synthesized MV hemagglutinin (MV-H), we tested the capability of recombinant MV-H proteins to downregulate CD46. Recombinant MV-H proteins of MV strains Edmonston, Halle, and CM led to the down-regulation of CD46, whereas those of DL and WTF did not. This observed differential downregulation by different MV strains has profound consequences, since lack of CD46 on the cell surface leads to susceptibility of cells to complement lysis. These results suggest that lymphotropic wild-type strains of MV which do not downregulate CD46 may have an advantage for replication in vivo. The relatively weak immune response against attenuated vaccine strains of MV compared with wild-type strains might be related to this phenomenon.

Identification of a DNA transformation gene required for com101A+ expression and supertransformer phenotype in Haemophilus influenzae.

DNA sequencing, RNA mapping, and protein expression experiments revealed the presence of a gene, tfoX+, encoding a 24.9-kDa polypeptide, that is transcribed divergently from a common promoter region with the Haemophilus influenzae rec-1+ gene. H. influenzae strains mutant for tfoX failed to bind transforming DNA and were transformation deficient. Primer extension experiments utilizing in vivo total RNA from precompetent and competent H. influenzae cells demonstrated that transcription of tfoX+ increased immediately upon competence induction, suggesting that tfoX+ is an early competence gene. Similar experiments showed that the expression of the late competence-specific gene, com101A+, was tfoX+ dependent. Moreover, expression of plasmid-borne tfoX+ in H. influenzae resulted in constitutive competence. The addition of cyclic adenosine monophosphate (cAMP) to strains carrying a tfoX::lacZ operon fusion resulted in an immediate increase in beta-galactosidase activity that correlated with an increase in genetic transformability. Collectively, our results suggest that TfoX may play a key role in the development of genetic competence by regulating the expression of late competence-specific genes.

Menu-planning guide for school lunches, based on WFA requirements for type A and type B lunches.

"Issued September 1943, revised September 1944."

Operator and organizational maintenance manual : life preserver, underarm, parachutist, type B-7, CO, inflated, FSN 4220-657-2197.

"December 1970."

Characterisation of resistance to ß-lactam antibiotics in a population of Haemophilus influenzae

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Molecular organization of small plasmids bearing blaTEM-1 and conferring resistance to β-lactams in Haemophilus influenzae

TEM-1 is the dominant β-lactamase of Haemophilus influenzae and can be located on small plasmids. Three distinct plasmids with sizes from 4,304 to 5,646 nucleotides (nt) were characterized: pA1606, pA1209, and pPN223. In addition to TEM-1 and a replication enzyme of the Rep 3 superfamily, pA1606 carries a Tn3 resolvase gene and pA1606 and pA1209 carry an open reading frame (ORF) similar to a plasmid recombination enzyme gene described in Gram-positive bacteria. The plasmids transformed strain Rd to the ampicillin-resistant phenotype.

Haemophilus influenzae clinical isolates with plasmid pB1000 bearing blaROB-1: fitness cost and interspecies dissemination

Plasmid pB1000 is a mobilizable replicon bearing the bla(ROB-1) beta-lactamase gene that we have recently described in Haemophilus parasuis and Pasteurella multocida animal isolates. Here we report the presence of pB1000 and a derivative plasmid, pB1000', in four Haemophilus influenzae clinical isolates of human origin. Pulsed-field gel electrophoresis showed unrelated patterns in all strains, indicating that the existence of pB1000 in H. influenzae isolates is not the consequence of clonal dissemination. The replicon can be transferred both by transformation and by conjugation into H. influenzae, giving rise to recipients resistant to ampicillin and cefaclor (MICs, > or =64 microg/ml). Stability experiments showed that pB1000 is stable in H. influenzae without antimicrobial pressure for at least 60 generations. Competition experiments between isogenic H. influenzae strains with and without pB1000 revealed a competitive disadvantage of 9% per 10 generations for the transformant versus the recipient. The complete nucleotide sequences of nine pB1000 plasmids from human and animal isolates, as well as the epidemiological data, suggest that animal isolates belonging to the Pasteurellaceae act as an antimicrobial resistance reservoir for H. influenzae. Further, since P. multocida is the only member of this family that can colonize both humans and animals, we propose that P. multocida is the vehicle for the transport of pB1000 between animal- and human-adapted members of the Pasteurellaceae.

Análisis económico de las vacunas 10-valente y 13-valente contra neumococo: revisión sistemática

Introducción: Las vacunas clásicamente han representado un método económico y eficaz para el control y prevención de múltiples enfermedades infecciosas. En los últimos años se han introducido nuevas vacunas contra neumococo a precios elevados, y los diferentes análisis económicos a nivel mundial de estas vacunas no muestran tendencias. El objetivo de este trabajo era resumir la evidencia existente a través de los diferentes estudios económicos evaluando las dos vacunas de segunda generación contra neumococo en la población a riesgo. Metodología: En este trabajo se realizo una revisión sistemática de la literatura en 8 bases de datos localizadas en diferentes partes del mundo y también que tuvieran literatura gris. Los artículos fueron inicialmente evaluados acorde a su titulo y resumen, posteriormente los elegidos se analizaron en su totalidad. Resultados: Se encontraron 404 artículos, de los cuales 20 fueron incluidos en el análisis final. Se encontró que la mayoría de los estudios se realizaron en áreas donde la enfermedad tiene una carga baja, como es Norte América y Europa, mientras que en los lugares del mundo donde la carga es mas alta, se realizaron pocos estudios. De igual manera se observo que la mayoría de los estudios mostraron por los menos ser costo efectivos respecto a la no vacunación, y en su totalidad las dos vacunas de segunda generación mostraron costo efectividad respecto a la vacunación con PCV-7. Los resultados de los estudios son muy heterogéneos, hasta dentro del mismo país, señalando la necesidad de guías para la conducción de este tipo de estudios. De igual manera, la mayoría de los estudios fueron financiados por farmacéuticas, mientras en un numero muy reducido por entes gubernamentales. Conclusiones: La mayoría de los estudios económicos sobre las vacunas de segunda generación contra neumococo han sido realizados en países con un alto índice de desarrollo económico y patrocinados por farmacéuticas. Dado que la mayoría de la carga de la enfermedad se encuentran en regiones con un menor nivel de desarrollo económico se deberían realizar mas en estas zonas. De igual manera, al ser la vacunación un asunto de salud publica y con un importante impacto económico los gobiernos deberían estar mas involucrados en los mismos.

Cost-effectiveness of introducing the 10-valent pneumococcal conjugate vaccine into the universal immunisation of infants in Brazil

Background Cost-effectiveness studies have been increasingly part of decision processes for incorporating new vaccines into the Brazilian National Immunisation Program. This study aimed to evaluate the cost-effectiveness of 10-valent pneumococcal conjugate vaccine (PCV10) in the universal childhood immunisation programme in Brazil. Methods A decision-tree analytical model based on the ProVac Initiative pneumococcus model was used, following 25 successive cohorts from birth until 5 years of age. Two strategies were compared: (1) status quo and (2) universal childhood immunisation programme with PCV10. Epidemiological and cost estimates for pneumococcal disease were based on National Health Information Systems and literature. A 'top-down' costing approach was employed. Costs are reported in 2004 Brazilian reals. Costs and benefits were discounted at 3%. Results 25 years after implementing the PCV10 immunisation programme, 10 226 deaths, 360 657 disability-adjusted life years (DALYs), 433 808 hospitalisations and 5 117 109 outpatient visits would be avoided. The cost of the immunisation programme would be R$10 674 478 765, and the expected savings on direct medical costs and family costs would be R$1 036 958 639 and R$209 919 404, respectively. This resulted in an incremental cost-effectiveness ratio of R$778 145/death avoided and R$22 066/DALY avoided from the society perspective. Conclusion The PCV10 universal infant immunisation programme is a cost-effective intervention (1-3 GDP per capita/DALY avoided). Owing to the uncertain burden of disease data, as well as unclear long-term vaccine effects, surveillance systems to monitor the long-term effects of this programme will be essential.

Serologic vaccination response after solid organ transplantation: a systematic review

BACKGROUND Infectious diseases after solid organ transplantation (SOT) are one of the major complications in transplantation medicine. Vaccination-based prevention is desirable, but data on the response to active vaccination after SOT are conflicting. METHODS In this systematic review, we identify the serologic response rate of SOT recipients to post-transplantation vaccination against tetanus, diphtheria, polio, hepatitis A and B, influenza, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitides, tick-borne encephalitis, rabies, varicella, mumps, measles, and rubella. RESULTS Of the 2478 papers initially identified, 72 were included in the final review. The most important findings are that (1) most clinical trials conducted and published over more than 30 years have all been small and highly heterogeneous regarding trial design, patient cohorts selected, patient inclusion criteria, dosing and vaccination schemes, follow up periods and outcomes assessed, (2) the individual vaccines investigated have been studied predominately only in one group of SOT recipients, i.e. tetanus, diphtheria and polio in RTX recipients, hepatitis A exclusively in adult LTX recipients and mumps, measles and rubella in paediatric LTX recipients, (3) SOT recipients mount an immune response which is for most vaccines lower than in healthy controls. The degree to which this response is impaired varies with the type of vaccine, age and organ transplanted and (4) for some vaccines antibodies decline rapidly. CONCLUSION Vaccine-based prevention of infectious diseases is far from satisfactory in SOT recipients. Despite the large number of vaccination studies preformed over the past decades, knowledge on vaccination response is still limited. Even though the protection, which can be achieved in SOT recipients through vaccination, appears encouraging on the basis of available data, current vaccination guidelines and recommendations for post-SOT recipients remain poorly supported by evidence. There is an urgent need to conduct appropriately powered vaccination trials in well-defined SOT recipient cohorts.

Conservation and accessibility of an inner core lipopolysaccharide epitope of Neisseria meningitidis

We investigated the conservation and antibody accessibility of inner core epitopes of Neisseria meningitidis lipopolysaccharide (LPS) because of their potential as vaccine candidates. An immunoglobulin G3 murine monoclonal antibody (MAb), designated MAb B5, was obtained by immunizing mice with a galE mutant of N. meningitidis H44/76 (B.15.P1.7,16 immunotype L3). We have shown that MAb B5 can bind to the core LPS of wild-type encapsulated MC58 (B.15.P1.7,16 immunotype L3) organisms in vitro and ex vivo. An inner core structure recognized by MAb B5 is conserved and accessible in 26 of 34 (76%) of group B and 78 of 112 (70%) of groups A, C, W, X, Y, and Z strains. N. meningitidis strains which possess this epitope are immunotypes in which phosphoethanolamine (PEtn) is linked to the 3-position of the beta-chain heptose (HepII) of the inner core. In contrast, N. neningitidis strains lacking reactivity with MAb B5 have an alternative core structure in which PEtn is linked to an exocyclic position (i.e., position 6 or 7) of HepII (immunotypes L2, L4, and L6) or is absent (immunotype L5). We conclude that MAb B5 defines one or more of the major inner core glycoforms of N. meningitidis LPS. These findings support the possibility that immunogens capable of eliciting functional antibodies specific to inner core structures could be the basis of a vaccine against invasive infections caused by N. meningitidis.