The use of magnetic resonance imaging (MRI) provides visual evidence of cerebral deposits of paramagnetic metals. The usefulness of MRI is described in connection with the manganese poisoning of a 44 year old arc welder who had been engaged in the repair and recycling of railroad track made of manganese steel alloy. (British Journal of Industrial Medicine 1993;50:510-513) The diagnosis of manganese (Mn) (fig 1 top). The T, signals were unremarkable (fig 1 bottom).Repeat MRI six months after stopping work ( fig 2) showed almost complete resolution of the high intensity signals in the midbrain. A single photon emission computed tomography scan showed on 27 April 2019 by guest. Protected by copyright.

The ability of unencapsulated (nontypeable) Haemophilus influenzae (NTHi) to cause systemic disease in healthy children has been recognized only in the past decade. To determine the extent of similarity among invasive nontypeable isolates, we compared strain R2866 with 16 additional NTHi isolates from blood and spinal fluid, 17 nasopharyngeal or throat isolates from healthy children, and 19 isolates from middle ear aspirates. The strains were evaluated for the presence of several genetic loci that affect bacterial surface structures and for biochemical reactions that are known to differ among H. influenzae strains. Eight strains, including four blood isolates, shared several properties with R2866: they were biotype V (indole and ornithine decarboxylase positive, urease negative), contained sequence from the adhesin gene hia, and lacked a genetic island flanked by the infA and ksgA genes. Multilocus sequence typing showed that most biotype V isolates belonged to the same phylogenetic cluster as strain R2866. When present, the infA-ksgA island contains lipopolysaccharide biosynthetic genes, either lic2B and lic2C or homologs of the losA and losB genes described for Haemophilus ducreyi. The island was found in most nasopharyngeal and otitis isolates but was absent from 40% of invasive isolates. Overall, the 33 hmw-negative isolates were much more likely than hmw-containing isolates to have tryptophanase, ornithine decarboxylase, or lysine decarboxylase activity or to contain the hif genes. We conclude (i) that invasive isolates are genetically and phenotypically diverse and (ii) that certain genetic loci of NTHi are frequently found in association among NTHi strains.

Findings confirm the safety of gadopentetate dimeglumine.

The gram-negative bacterium Haemophilus influenzae is a human-restricted commensal of the nasopharynx that can also be associated with disease. The majority of H. influenzae respiratory isolates lack the genes for capsule production and are nontypeable (NTHI). Whereas encapsulated strains are known to belong to serotype-specific phylogenetic groups, the structure of the NTHI population has not been previously described. A total of 656 H. influenzae strains, including 322 NTHI strains, have been typed by multilocus sequence typing and found to have 359 sequence types (ST). We performed maximum-parsimony analysis of the 359 sequences and calculated the majority-rule consensus of 4,545 resulting equally most parsimonious trees. Eleven clades were identified, consisting of six or more ST on a branch that was present in 100% of trees. Two additional clades were defined by branches present in 91% and 82% of trees, respectively. Of these 13 clades, 8 consisted predominantly of NTHI strains, three were serotype specific, and 2 contained distinct NTHI-specific and serotype-specific clusters of strains. Sixty percent of NTHI strains have ST within one of the 13 clades, and eBURST analysis identified an additional phylogenetic group that contained 20% of NTHI strains. There was concordant clustering of certain metabolic reactions and putative virulence loci but not of disease source or geographic origin. We conclude that well-defined phylogenetic groups of NTHI strains exist and that these groups differ in genetic content. These observations will provide a framework for further study of the effect of genetic diversity on the interaction of NTHI with the host.Haemophilus influenzae is a small (1 to 2 m in length) gram-negative bacterium that is found only in humans. The polysaccharide-protein conjugate vaccines against serotype b H. influenzae have almost eliminated H. influenzae as a cause of pediatric meningitis in the western world. However, unencapsulated (nontypeable) H. influenzae (NTHI) remains an important pathogen, particularly in children and the elderly (5,8,23). NTHI infections are usually limited to respiratory mucosal sites such as the middle ear or bronchi but are occasionally systemic. It is not known whether NTHI isolates associated with localized or systemic disease are genetically distinct from each other or distinct from isolates associated with asymptomatic colonization of the nasopharynx.Efforts to understand and control NTHI disease have been hampered by the diversity of these bacteria. Many of the surface antigens that have been studied display interstrain and intrastrain heterogeneity as a result of both sequence divergence and phase variation. It is increasingly recognized that NTHI isolates also vary in genetic content. We use the term island to refer to a genetic locus (one or more genes) that occurs in some but not all strains. As used here, the term does not imply that the locus is known to be readily transferred between strains or is thought to have been recently acquired. Islands whose functi...

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