[Bartter disease with neurosensitive deafness (Bartter type IV). A clinical entity described 10 years ago].
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Bartter Syndrome↗
Biomedical subjects
F Claverie-Martín
Publications and source records attributed to F Claverie-Martín.
[Dent disease. History and genetic causes of a tubulopathy].
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Genetic Predisposition to Disease↗
A PCR assay for rapid detection of vancomycin-resistant enterococci.
Since the first report of a vancomycin-resistant enterococcal clinical isolate, these Gram-positive bacteria have emerged as important nosocomial pathogens. Several glycopeptide resistance phenotypes can be distinguished on the basis of the level and inducibility of resistance to vancomycin and teicoplanin. In the present study, we developed a multiplex PCR, which allows the simultaneous identification of enterococci at the genus level and detection of the most frequent glycopeptide resistance genotypes. Five primer sets targeting the genes vanA, vanB, vanC1, vanC2/C3 and tuf were used in one reaction tube with bacterial DNA extracted from three to five colonies. This PCR method is suitable for the rapid detection of vancomycin-resistant enterococci.
DNA, Bacterial↗
Mupirocin resistance in methicillin-resistant Staphylococcus aureus clinical isolates in a Spanish hospital. Co-application of multiplex PCR assay and conventional microbiology methods.
A total of 1785 Staphylococcus aureus clinical isolates were collected in our hospital during 1998 (526), 1999 (564) and 2000 (695). Among them, one hundred and thirty (39, 33 and 58, respectively) were phenotypically assigned as methicillin-resistant Staphylococcus aureus (MRSA); sixteen of these isolates (3, 2 and 11, respectively) were detected as highly mupirocin-methicillin resistant Staphylococcus aureus (MMRSA). In this work, our goal was to characterize MRSA and MMRSA clinical isolates by co-application of phenotypic and genotypic methods in order to determine the MMRSA incidence in our hospital during the period 1998-2000. With this purpose we compared and integrated the results obtained using conventional microbiology methods with those obtained using a multiplex polymerase chain reaction (PCR) assay. Our results showed a good complementation between these two approximations to determine the incidence of MMRSA clinical isolates and permitted to estimate that such incidence increased from 7.7% in 1998 to 19% in 2000.
Bacterial Proteins↗
Multiplex PCR for simultaneous identification of Staphylococcus aureus and detection of methicillin and mupirocin resistance.
In this work, we describe a multiplex PCR assay for the detection of clinically relevant antibiotic resistance genes harbored by some Staphylococcus aureus isolates and for the simultaneous identification of such isolates at the species level. Conditions were optimized for the simultaneous detection of the 310-, 456-, and 651-bp regions of the mecA (encoding high-level methicillin resistance), ileS-2 (encoding high-level mupirocin resistance), and femB (encoding a factor essential for methicillin resistance) genes, respectively, from a single colony in a single reaction tube. The femB PCR fragment allows the specific identification of S. aureus. Validation of the method was performed using 50 human isolates of methicillin-resistant S. aureus (MRSA) and the appropriate control strains. This assay offers a rapid, simple, feasible, specific, sensitive, and accurate identification of mupirocin-resistant MRSA clinical isolates and could be systematically applied as a diagnostic test in clinical microbiology laboratories, facilitating the design and use of antibiotic therapy.
Anti-Bacterial Agents↗
Molecular cloning, tissue distribution, and chromosomal mapping of the human epithelial Ca2+ channel (ECAC1).
Functional and morphological analyses indicated that the epithelial Ca2+ channel (ECaC), which was recently cloned from rabbit kidney, exhibits the defining properties for being the gatekeeper in transcellular Ca2+ (re)absorption. Its human homologue provides, therefore, a molecular basis for achieving a better understanding of Ca2+ mal(re)absorption. By applying the RACE technique, the full-length cDNA of human ECaC (HGMW-approved symbol ECAC1) was obtained. It consisted of 2,772 bp with an open reading frame of 2,187 bp encoding a protein of 729 amino acids with a predicted molecular mass of 83 kDa. Phylogenetic analysis indicated that this highly selective Ca2+ channel exhibits a low level of homology (<30%) to other Ca2+ channels, suggesting that it belongs to a new family. hECaC was highly expressed in kidney, small intestine, and pancreas, and less intense expression was detected in testis, prostate, placenta, brain, colon, and rectum. These ECaC-positive tissues also expressed the 1,25-dihydroxyvitamin D3-sensitive calcium-binding proteins, calbindin-D9K and/or calbindin-D28K. The human ECaC gene mapped to chromosome 7q31.1-q31.2. Taken together, the conspicuous colocalization of hECaC and calbindins in organs that are not prime regulators of plasma Ca2+ levels could illustrate new pathways in cellular Ca2+ homeostasis.
Amino Acid Sequence↗
Glycopeptide resistance in enterococci.
The selective pressure resulting from the extensive use of antibiotics over the last 50 years has led to the emergence of bacterial resistance and to the dissemination of resistance genes among pathogenic microorganisms. Consequently, we are now at serious risk of suffering intractable, life-threatening infections. The progressive emergence and rapid dissemination of resistance to glycopeptides, the last resort for treating nosocomial infections with enterococci resistant to usual antibiotics, constitute one of the most dramatic examples of such resistance. Enterococci are normal human commensals, but are also a frequent cause of nosocomial urinary tract infections and nosocomial bacteremia. Enterococcus faecalis causes 80 to 90% of human enterococcal infections, while Enterococcus faecium accounts for most of the remainder. During the last decade, our understanding of the genetics and biochemical basis of resistance to glycopeptides has increased greatly. Furthermore, the application of molecular methods for the diagnosis of glycopeptide-resistant enterococci has provided new insights into the epidemiology of enterococcal infections.
Animals↗
Extracellular release of protease III (ptr) by Escherichia coli K12.
Escherichia coli strains carrying the protease III structural gene (ptr) on a plasmid secreted the protein into the growth medium. Plasmid-encoded beta-lactamase and chloramphenicol acetyl transferase, which served as periplasmic and cytoplasmic markers during cell fractionation, were not released into the growth medium. There appeared to be some strain dependence on the proficiency of the secretion system. Protease III was not detectably processed upon export through the outer cell membrane.
Blotting, Western↗
Transcript mapping using [35S]DNA probes, trichloroacetate solvent and dideoxy sequencing ladders: a rapid method for identification of transcriptional start points.
A simple method for RNA transcript mapping has been developed that combines the use of 35S-labeled M13 DNA probes and the presence of high concentrations of sodium trichloroacetate in the hybridization buffer. These hybridization conditions permit the use of M13 probes without purification from the template. The dideoxy sequencing ladders used for sizing the protected DNA fragments are obtained from the same M13 templates utilized to synthesize the DNA probes. The method was tested by analyzing the transcripts controlled by lac, ptr and trxA promoters. Comparison of the results with previously published data obtained with the conventional S1 nuclease mapping technique indicated that the present method is just as precise and at least 50 times more sensitive. Clones constructed for sequencing a gene of interest can be used directly to identify transcriptional start points.
Base Sequence↗
[Neonatal Bartter disease diagnosed with the detection of a mutation of the KCNJ1 gene which codifies the synthesis of the renal ROMK1 potassium channel].
We report clinical data of a female patient with Bartter's syndrome who was initially diagnosed with idiophatic hypercalciuria and, subsequently, with hyperprostaglandin E, syndrome. The patient was born after premature delivery with a history of polyhydramnios. During the first two years of life, in spite of evidence for significant failure to thrive, polyuria and special tendency to dehydration, she had no hypokalemia. The acid-base balance was normal except metabolic acidosis during the first few days after she was born. When hypercalciuria was observed, she was treated with thiazides and a low-salt diet. With such treatment she frequently showed hypokalemic alkalosis. Afterwards, once it was possible to determine the levels of renin and aldosterone and the urinary excretion of PGE2, we suspected the diagnosis. DNA sequencing analysis showed that the patient carried a homozygotic mutation in the KCNJ1 gene, coding for the potassium channel ROMK, which results in the premature termination of the protein. It is the first time that this mutation has been found in Spain. The detection of this mutation confirmed a disease that was initially of uncertain diagnosis.
Bartter Syndrome↗
[Chondrocalcinosis and hypomagnesaemia in a patient with a new mutation in the gene of the thiazide-sensitive Na-Cl cotransporter].
We report the clinical history of an adult patient that debuted during adolescence with sharp episodes of arthritis several joints, with affectation of big articulations of superior and inferior members, in absence of renal symptoms. An X-ray showed calcification of the menisci in both knees, the symphysis of the pubis and of other joints. When the presence of hypomagnesaemia was demonstrated, we observed that he also had hypokalemia, hypocalciuria, increment of the urinary elimination of magnesium, slightly high levels of renin, dilution defect and a moderate reduction of the NaCl tubular distal reabsorption, all compatible with the diagnosis of Gitelman syndrome. We sequenced the exons and intron flanking regions of the SLC12A3 gene, encoding the thiazide-sensitive Na-Cl cotransporter, and showed that the patient is homozygous for a new mutation in intron 7. This mutation consisted of a G to A transition at position +1 of the donor splice site of intron 7.
Adolescent↗