Search PubMed⌕ Search

Biomedical subjects

M B Connelly

Publications and source records attributed to M B Connelly.

4 recordsLinked to original sources
PubMed2000

Surgical management of coccidioidomycosis in children.

BACKGROUND/PURPOSE: Operations for Coccidioides immitis infection in children have received little study. The authors perceived an increase in the number of patients requiring operations for coccidioidomycosis at Phoenix Children's Hospital. The authors therefore reviewed the surgical management of children with C immitis infection in Phoenix, Arizona. METHODS: The medical records of all children hospitalized from 1994 to 1999 with a confirmed laboratory diagnosis of coccidioidomycosis were reviewed. Age, gender, race, immune status, laboratory data, operations, and outcome were recorded. RESULTS: Of 39 children with proven coccidioidomycosis, 21 patients (54%) underwent a total of 49 operations. Boys represented 72% of all children reviewed. Sixteen patients (29% of the operative cohort) were immunocompromised. Thoracic procedures (19 cases) were most frequent. CONCLUSIONS: Over half the children hospitalized for coccidioidomycosis required at least 1 operation. Most were immunocompetent boys with thoracic disease. Pediatric surgeons, who provide the bulk of operative care, should expect to encounter coccidioidomycosis in endemic areas, and increasingly in nonendemic areas.

Adolescent↗
PubMed1996

Mutations at two invariant nucleotides in the 3'-minor domain of Escherichia coli 16 S rRNA affecting translational initiation and initiation factor 3 function.

We have investigated the highly conserved GAUCA sequence of small subunit ribosomal RNA. Within this region, the invariant nucleotides G1530 and A1531 of Escherichia coli 16 S rRNA were mutagenized to A1530/G1531. These base changes caused a lethal phenotype when expressed from a high copy number plasmid. In low copy number plasmids, the mutant ribosomes had limited effects when expressed in vivo but caused significant deficiencies in translation in vitro, affecting enzymatic tRNA binding, non-enzymatic tRNA binding, subunit association, and initiation factor 3 (IF3) binding. Mutant 30 S ribosomal subunits showed a 10-fold decrease in affinity for IF3 as compared to wild-type subunits but showed an increased affinity for IF3 when in 70 S ribosomes. Additionally, IF3 did not promote dissociation of 70 S ribosomes, which had mutated subunits as monitored by light-scattering experiments. However, extension inhibition experiments (toeprinting) showed that IF3 retained its ability to discriminate between initiator and elongator tRNAs on mutated subunits. The results indicate that the two functions of IF3, tRNA discrimination and subunit dissociation, are separable and that the invariant nucleotides are important for correct subunit function during initiation.

Bacterial Proteins↗
PubMed1992

Primary structure of cobra complement component C3.

Complement component C3 is a multifunctional protein known to interact specifically with more than 10 different plasma proteins or cell surface receptors. Cobra venom contains cobra venom factor, a structural analogue of C3 that shares some properties with C3 (e.g., formation of a C3/C5 convertase) but differs in others (e.g., susceptibility to regulation by factors H and I). The elucidation of structural differences between C3 and cobra venom factor can be expected to help identify functionally important regions of C3 molecules. To that end we have undertaken the molecular cloning of both cobra C3 and cobra venom factor to take advantage of the unique biologic system where both proteins are produced by the same species. We report the primary structure of cobra C3 mRNA and the derived protein structure. Cobra C3 mRNA is 5211 bp in length. It contains an open reading frame of 4953 bp coding for a single pre-pro-C3 molecule, consisting of a 22-amino acid signal sequence, a 633-amino acid beta-chain (70 kDa), and a 992-amino acid alpha-chain (112 kDa) which is separated from the beta-chain by four arginine residues. There are no N-glycosylation sites in cobra C3. Cobra C3 exhibits approximately 58% nucleotide sequence identity with C3 from mammalian species. At the protein level, sequence identity is approximately 52% and sequence similarity approximately 71%. All 27 cysteine residues are highly conserved as are the C3 convertase cleavage site, the thioester site, and the factor B binding site. Cobra C3 also seems to have homologous binding sites for factor H and properdin, as well as a conserved sequence in the functionally important region of the C3a anaphylatoxin. The sequence homology at the CR2 and CR3 binding sites does not exceed the overall sequence homology. Accordingly, the existence of CR2 and CR3 binding sites can neither be deduced nor excluded.

Amino Acid Sequence↗