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Biomedical subjects

M C Jones

Publications and source records attributed to M C Jones.

At least 55 records · Page 3Linked to original sources
PubMed1996

Accuracy of four commercial systems for identification of Burkholderia cepacia and other gram-negative nonfermenting bacilli recovered from patients with cystic fibrosis.

Burkholderia cepacia has recently been recognized as an important pathogen in chronic lung disease in patients with cystic fibrosis (CF). Because of the social, psychological, and medical implications of the isolation of B. cepacia from CF patients, accurate identification of this organism is essential. We compared the accuracies of four commercial systems developed for the identification of nonfermenting, gram-negative bacilli with that of conventional biochemical testing for 150 nonfermenters including 58 isolates of B. cepacia recovered from respiratory secretions from CF patients. The accuracies of the four systems for identifying all nonfermenters ranged from 57 to 80%, with the RapID NF Plus system being most accurate. The accuracies of these systems for identifying B. cepacia ranged from 43 to 86%, with the Remel system being most accurate. Depending on the commercial system, from two to seven isolates were misidentified as B. cepacia. The relatively poor performance of the commercial systems requires that identification of certain nonfermenters be confirmed by conventional biochemical testing. These organisms include B. cepacia, Burkholderia sp. other than B. cepacia, and infrequently encountered environmental species (Pseudomonas and Flavobacterium species). In addition, conventional biochemical testing should be done if a commercial system fails to assign an identification to an organism. Confirmatory testing should preferably be performed by a reference laboratory with experience in working organisms isolated from CF patients.

Bacteriological Techniques↗
PubMed1996

Acquired perforating dermatosis in a British dialysis population.

A perforating disorder of the skin developing in association with chronic renal failure and often also diabetes, acquired perforating dermatosis (APD), affects up to 10% of patients receiving maintenance haemodialysis in North America. The prevalence of this condition in British dialysis patients has not yet been ascertained. We have undertaken a skin survey of our dialysis population (n = 80) to determine the prevalence and clinical presentation of APD, with subsequent assessment of disease management and outcome. Of 72 patients who participated in the survey, eight were found to have APD, seven of whom were also diabetic. Skin lesions had developed pre-dialysis in two patients, on commencement of dialysis in one, and after 1-3 years on dialysis in the remaining five. Patients typically presented with pruritic dome-shaped papules with central crusts arising on the trunk and extensor limb surfaces. Histological examination of biopsy specimens revealed two types of lesion, typified by either narrow or broad ulcer craters, each showing perforation of both collagen and elastic fibres. Topical/intradermal steroid or topical retinoid were effective therapies in certain of our patients. Clinical clearance was achieved after 3-12 months of treatment in five patients with improvement in the remaining two patients who received treatment. Of the four patients who were alive at 2-year review, three remained clear, while one patient continued to develop new lesions. We report an 11% prevalence of APD in our dialysis population, suggesting the disorder to be as prevalent in patients with chronic renal failure in Britain as in North America. An association of the disorder with long-standing diabetes was confirmed.

Adult↗
PubMed1995

Case report: periosteal new bone formation in Takayasu arteritis.

Periosteal new bone formation is recognized as a rare feature of arteritis but has not previously been described in association with Takayasu arteritis. We report the first case of Takayasu arteritis complicated by multifocal periosteal new bone formation of both clavicles and one scapula.

Adult↗
PubMed1995

Novel FGFR2 mutations in Crouzon and Jackson-Weiss syndromes show allelic heterogeneity and phenotypic variability.

Mutations have been reported for several craniosynostotic disorders in exon IIIa (exon U or 7) or IIIc (exon B or 9) of the fibroblast growth factor receptor 2 gene (FGFR2). Among the conditions with FGFR2 mutations are two autosomal dominant syndromes, Crouzon and Jackson-Weiss. In this study, 24 Crouzon and one Jackson-Weiss syndrome patients were screened for mutations in the two exons by direct sequencing, and mutations were detected in 28% (7/25) of all cases. Five different mutations were found including two novel (W290G, C342W) and two previously reported, recurrent mutations for Crouzon syndrome (A344A, S354C), and one new mutation for Jackson-Weiss syndrome (C342R). The W290G mutation was found in exon IIIa which is common to both alternatively spliced forms of FGFR2, BEK (expressed predominantly in primordial bones) and KGFR (expressed preferentially in epithelia). Atypical Crouzon syndrome features of epithelial-derived anal and/or external ear anomalies were present in the two affected family members with the mutation. This phenotype possibly reflects the expression of both mutant BEK and KGFR. In addition, the Jackson-Weiss syndrome mutation, C342R, in exon IIIc was observed previously in other craniosynostotic syndromes, Crouzon and Pfeiffer. These results underscore the allelic heterogeneity of these conditions and the complexity of the phenotypic consequences of FGFR2 mutations.

Alleles↗
PubMed1995

Comparison of antimicrobial susceptibility methods for detection of penicillin-resistant Streptococcus pneumoniae.

We sought to determine if commercially available susceptibility tests were accurate in detecting penicillin resistance and relative resistance in Streptococcus pneumoniae. We compared the reference MIC method with oxacillin disk screening and three commercial tests, E-test (AB Biodisk), JustOne (Radiometer America), and MicroScan Pos MIC Panel Type 6 (Baxter Diagnostics), with 80 selected clinical isolates. Thirty-three additional isolates were tested by the reference method and the E-test to further validate the latter method. Oxacillin screening was effective in detecting all penicillin-resistant and relatively resistant strains of S. pneumoniae. The MicroScan method was not effective in detecting penicillin resistance or relative resistance. The JustOne system classified only 6 (35%) of 17 resistant strains correctly, with 11 resistant strains classified as relatively resistant. The E-test correctly classified 30 (83%) of 36 resistant isolates, with 6 resistant isolates interpreted as relatively resistant. For determining penicillin MICs for S. pneumoniae, the E-test was the most accurate of the commercial systems that we studied.

Humans↗
PubMed1995

Quality assurance study of bacterial antigen testing of cerebrospinal fluid.

Bacterial antigen testing (BAT) of cerebrospinal fluid (CSF) by latex agglutination is a low-yield procedure in patients whose CSF specimens have normal laboratory parameters. Between August 1992 and August 1994, we evaluated 287 bacterial antigen (BA) test requests to determine whether yields could be improved and whether patient costs could be reduced by cancelling BAT for those patients with normal CSF parameters (cell count, protein, glucose) after consultation with physicians. A total of 171 (68%) BA tests were canceled by this approach. None of these CSF specimens was culture positive for an organism detectable by BAT. Of the remaining 116 CSF specimens tested, only 3 were positive by BAT, one each for Neisseria meningitidis, Streptococcus pneumoniae, and group B streptococcus. Only 43 of the CSF specimens tested had at least two abnormal parameters; the 3 positive CSF specimens were included in this group. In light of the low rate of positivity, the number of BA tests can be further reduced by establishing criteria that must be met before a CSF specimen is accepted for BAT. After review of our data and the literature concerning this topic, we concluded that only specimens with leukocyte counts of > or = 50 cells per mm3 should be tested. Of 287 specimens evaluated in our study, only 36 met this criterion, including the 3 BA-positive specimens. Enacting such a restriction would have reduced the total number of BA tests by 251 (87%) without compromising patient care. A laboratory cost savings of $6,500 per year would have been realized, with a substantial reduction in the cost per positive test. Patient charges would have been reduced by $12,500 per year.

Adolescent↗
PubMed1995

Kabuki syndrome: underdiagnosed recognizable pattern in cleft palate patients.

Eight cases of Kabuki syndrome in non-Japanese patients are presented. (Although the name Kabuki Make-up syndrome has been used to identify this condition, the authors recommend that the term "make-up" be deleted from the designation as it has caused problems with some of the families.) Clinical features include a characteristic facies, developmental delay, musculoskeletal abnormalities, and dermatoglyphic differences. The phenotype appears to evolve over time making the diagnosis difficult in infancy. The progressive changes in the facial characteristics as well as the musculoskeletal problems suggest an underlying defect of the connective tissue. Finally, the syndrome appears to be more common in the non-Japanese population than previously appreciated, particularly in the cleft palate population.

Abnormalities, Multiple↗
PubMed1995

Craniofacial abnormalities, agenesis of the corpus callosum, polysyndactyly and abnormal skin and gut development--the Curry Jones syndrome.

Five children are described with a striking, asymmetric facial appearance, craniosynostosis, preaxial polysyndactyly, agenesis of the corpus callosum and unusual skin with streaky areas of atrophy. The gut and mucous membranes are involved in two patients. This paper includes two patients described by Gorlin (1990) under the designation of the Curry Jones syndrome.

Abnormalities, Multiple↗
PubMed1995

Non-steroidal anti-inflammatory drugs and hospitalization for acute renal failure.

Non-steroidal anti-inflammatory drugs (NSAIDs) have been implicated in the aetiology of acute renal failure (ARF), but epidemiological studies examining this association have produced disparate results. We conducted a case-control study using a purpose-built record-linkage database for a population of 420,600 patients, resident in Tayside since May 1990. Patients (n = 207) hospitalized with a diagnostic code for ARF between 1990 and 1992 had their diagnosis validated by a renal physician. Six community controls and two hospital controls, matched for age and sex, were generated for each of these cases. Exposure to dispensed oral NSAIDs, topical NSAIDs and aspirin during the 90 days prior to the index date were investigated (recent exposure), as was exposure at any time since January 1989 (previous exposure). The most significant associations were modelled using conditional logistic regression. When community controls were used, recent exposure to NSAIDs and previous exposure to aspirin were independently associated with hospitalization for ARF, with adjusted odds ratios of 2.20 (1.49-3.25) and 2.19 (1.46-3.30), respectively. Only recent exposure to oral NSAIDs was associated when hospital controls were used: 1.84 (1.14-2.93). No significant interactions were present with previous chronic renal failure, other possible causes of ARF or whether the diagnosis was primary or secondary. There is an approximate doubling of the risk of hospitalization for ARF with use of oral NSAIDs.

Acute Kidney Injury↗
PubMed1995

Clinical and molecular characterization of patients with distal 11q deletions.

Jacobsen syndrome is caused by segmental aneusomy for the distal end of the long arm of chromosome 11. Typical features include mild to moderate psychomotor retardation, trigonocephaly, facial dysmorphism, cardiac defects, and thrombocytopenia, though none of these features are invariably present. To define the critical regions responsible for these abnormalities, we studied 17 individuals with de novo terminal deletions of 11q. The patients were characterized in a loss-of-heterozygosity analysis using polymorphic dinucleotide repeats. The breakpoints in the complete two-generation families were localized with an average resolution of 3.9 cM. Eight patients with the largest deletions extending from 11q23.3 to 11qter have breakpoints, between D11S924 and D11S1341. This cytogenetic region accounts for the majority of 11q- patients and may be related to the FRA11B fragile site in 11q23.3. One patient with a small terminal deletion distal to D11S1351 had facial dysmorphism, cardiac defects, and thrombocytopenia, suggesting that the genes responsible for these features may lie distal to D11S1351. Twelve of 15 patients with deletion breakpoints as far distal as D11S1345 had trigonocephaly, while patients with deletions distal to D11S912 did not, suggesting that, if hemizygosity for a single gene is responsible for this dysmorphic feature, the gene may lie distal to D11S1345 and proximal to D11S912.

Abnormalities, Multiple↗
PubMed1994

Female infant with oncocytic cardiomyopathy and microphthalmia with linear skin defects (MLS): a clue to the pathogenesis of oncocytic cardiomyopathy?

A infant girl had red stellate skin lesions on the cheeks and neck, and mildly short palpebral fissures. Her skin abnormality was typical of microphthalmia with linear skin defects (MLS), a newly recognized syndrome consisting of congenital linear skin defects and ocular abnormalities in females monosomic for Xp22. She died suddenly and unexpectedly at age 4 months; the cause of death was ascribed to oncocytic cardiomyopathy. Oncocytic cardiomyopathy occurs only in young children, who present with refractory arrhythmias leading to cardiac arrest. The coexistence of two rare conditions, one of which is mapped to the X chromosome, and an excess of affected females with oncocytic cardiomyopathy, make it likely that oncocytic cardiomyopathy is also X-linked, with Xp22 being a candidate region. Overlapping manifestations in the two conditions (ocular abnormalities in cases of oncocytic cardiomyopathy and arrhythmias in MLS) offer additional support for this hypothesis.

Abnormalities, Multiple↗
PubMed1994

Recurrence of diaphragmatic agenesis associated with multiple midline defects: evidence for an autosomal gene regulating the midline.

We report the familial occurrence of diaphragmatic agenesis in association with other midline anomalies in a brother and sister. Opitz and Gilbert [Am J Med Genet 1982, 12:443-455] introduced the concept of the midline as a developmental field, and there have been reports of pedigrees compatible with the hypothesis of an X-linked gene regulating the development of the midline. This family suggests that an autosomal gene also contributes to the morphogenesis of midline structures.

Abnormalities, Multiple↗
PubMed1994

Mosaic triple trisomy in amniocytes from a phenotypically and karyotypically normal fetus.

We report the detection of a mosaic triple trisomy, 46,XY/49,XY,+13,+20,+21, in two amniotic fluid specimens obtained from a pregnancy that yielded a normal infant. Traditional cytogenetic methods failed to detect the abnormal cell lineage in fetal blood, foreskin, amnion, umbilical cord, and three different biopsies of the chorion. In addition, fluorescence in situ hybridization study of cells from a buccal smear showed no evidence of cells with three copies of chromosome 20.

Amniocentesis↗
PubMed1994

Cloning and characterisation of genes for tetrapyrrole biosynthesis from the cyanobacterium Anacystis nidulans R2.

The genes for 5-aminolevulinic acid dehydratase (ALAD) and uroporphyrinogen III synthase (UROS), two enzymes in the biosynthetic pathway for tetrapyrroles, were independently isolated from a plasmid-based genomic library of Anacystis nidulans R2 (also called Synechococcus sp. PCC7942), by their ability to complement Escherichia coli strains carrying mutations in the equivalent genes (hemB and hemD respectively). The identity of the genes was confirmed by comparing the appropriate enzyme activities in complemented and mutant strains. Subclones of the original plasmids that were also capable of complementing the mutants were sequenced. The inferred amino acid sequence of the cyanobacterial HemB protein indicates a significant difference in the metal cofactor requirement from the higher-plant enzymes, which was confirmed by overexpression and biochemical analysis. The organisation of the cyanobacterial hemD locus differs markedly from other prokaryotes. Two open reading frames were found immediately upstream of hemD. The product of one shows considerable similarity to published sequences from other organisms for uroporphyrinogen III methylase (UROM), an enzyme involved in the production of sirohaem and cobalamins (including vitamin B-12). The product of the other shows motifs which are similar to those found in proteins responsible for metabolic regulation in yeast and indicates that this family of transcription control proteins, which has previously been reported only from eukaryotes, is also represented in prokaryotes.

Amino Acid Sequence↗
PubMed1994

Calcium acetate versus calcium carbonate as phosphate-binding agents in chronic haemodialysis.

Hyperphosphataemia plays a key role in the pathogenesis of renal osteodystrophy, and phosphate-binding agents are required in many chronic dialysis patients. Aluminium hydroxide and calcium carbonate are well-established phosphate binders, but their use is associated with toxicity or poor efficacy. Calcium acetate is known to be a potent phosphate binder, and has recently been used successfully in chronic dialysis patients. In this randomized cross-over trial in 31 chronic haemodialysis patients, equimolar doses of calcium acetate and calcium carbonate were administered for 6 weeks each. Compliance was estimated from tablet counts, and biochemical parameters were measured at the end of each treatment period. Of the 31 patients 23 completed both treatment arms; of the remainder, three withdrew due to adverse symptoms, hypercalcaemia necessitated treatment withdrawal in two, and three died. Non-compliance was significantly higher with acetate (18.3% tablets not taken) than with carbonate (8.7%). Serum phosphate was significantly lower after treatment with acetate (1.51 mmol/l) than with carbonate (1.80), as was the Ca x PO4 product (3.59 vs 4.18 respectively) and PTH (17.8 vs 25.4 pmol/l respectively). Serum calcium was significantly higher after acetate therapy (2.40 vs 2.32 mmol/l). No significant difference was found for sodium, potassium, bicarbonate, urea, creatinine, and haemoglobin. This study confirms that the treatment of hyperphosphataemia is more effective with calcium acetate than with calcium carbonate. For the first time an associated beneficial effect on secondary hyperparathyroidism has also been demonstrated. Patient tolerability of calcium acetate was considerably poorer, probably due in part to tablet formulation and bulkiness, as well as possible direct gastrointestinal effects of the acetate salt.

Acetates↗