Inadequate management of blood pressure in a hypertensive population.
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Aged↗
Biomedical subjects
L A Sechi
Publications and source records attributed to L A Sechi.
Simple and rapid identification of different species of Mycobacteria by PCR.
A simple polymerase chain reaction (PCR) assay for rapid identification of different species of mycobacteria was developed. This PCR is based on the use of conserved sequences to amplify the genome of several mycobacterial species. The amplification patterns obtained were specific and reproducible for the species tested. In particular, we could identify Mycobacterium tuberculosis and Mycobacterium bovis (both produced the same pattern), Mycobacterium avium, Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium chelonae, Mycobacterium peregrinum, Mycobacterium fortuitum, Mycobacterium gordonae and Mycobacterium smegmatis. Moreover, due to the numerous copies of the target sequences present in the genome, the PCR showed a very high level of sensitivity.
AIDS-Related Opportunistic Infections↗
Lipoprotein(a) and apolipoprotein(a) isoforms and proteinuria in patients with moderate renal failure.
BACKGROUND: Atherosclerotic diseases are a major cause of death in patients with renal failure. Increased serum concentrations of lipoprotein(a) [Lp(a)] have been established as a genetically controlled risk factor for these diseases and have been demonstrated in patients with moderate renal failure, suggesting that this lipoprotein contributes to the increased cardiovascular risk seen in these patients. Variable alleles at the apolipoprotein(a) [apo(a)] gene locus are the main determinants of the serum Lp(a) level in the general population. The purpose of this study was to investigate apo(a) isoforms in patients with moderate renal failure and mild proteinuria (less than 1.0 g/day). METHODS: In 250 consecutive subjects recruited at a hypertension clinic, we assessed the renal function by 24-hour creatinine clearance, proteinuria, and microalbuminuria, as well as the prevalence of atherosclerotic disease, and we also measured apo(a) isoforms, serum albumin, and Lp(a) concentrations. RESULTS: Moderate impairment of renal function (creatinine clearance, 30 to 89 ml/min per 1.73 m2 of body surface area) was found in 97 patients. Lp(a) levels were significantly greater in patients with moderate renal failure (21.7+/-23.9 mg/dl) as compared with patients with normal renal function (15.6+/-16.4 mg/dl, P<0.001), and an inverse correlation was observed between log Lp(a) and creatinine clearance (r = -0.181, P <0.01). However, no difference was found in the frequency of low molecular weight apo(a) isoforms between patients with normal (25.5%) and impaired (27.8%) renal function. Only patients with the smallest size apo(a) isoforms exhibited significantly elevated levels of Lp(a), whereas the large-size isoforms had similar concentrations in patients with normal and impaired renal function. No significant relationship was found between serum Lp(a) and proteinuria. Clinical and laboratory evidence of one or more events attributed to atherosclerosis was found in 9.8% of patients with normal renal function and 25.8% of patients with moderate renal failure (P<0.001). CONCLUSIONS: These results indicate that renal failure per se or other genes beside the apo(a) gene locus are responsible for the elevation of serum Lp(a) levels in patients with moderate impairment of renal function. The elevation of Lp(a) levels occurs independently of the level of proteinuria and may contribute to the risk for atherosclerotic disease in these patients.
Adult↗
Streptococcus equinus endocarditis in a patient with pulmonary histiocytosis X.
Although Streptococcus equinus has been isolated from the human bowel in an appreciable percentage of the adult general population, it has only rarely been described as a human pathogen. Our report describes the occurrence of S. equinus endocarditis in a patient who had no history of pre-existing heart disease, but who showed evidence of a late-stage pulmonary histiocytosis X. Endocarditis resolved promptly after antibiotic treatment, but required aortic valve substitution. Abnormalities of the immune system that have been demonstrated in patients with histiocytosis X could explain the occurrence of endocarditis in this patient.
Aged↗
Mechanisms of insulin resistance in rat models of hypertension and their relationships with salt sensitivity.
Several lines of evidence suggest that insulin resistance and the resultant hyperinsulinaemia are causally related to hypertension. Insulin actions are initiated by binding to a high-affinity transmembrane protein receptor which is present in all mammalian cells. These effects are predominant in skeletal muscle, liver, and fat and involve a number of tissue-specific and biochemically diverse events. Less well known are effects of insulin occurring in tissues not usually considered as insulin targets, which are hypothetical contributors to the pro-hypertensive action of the hormone. These effects include activation of renal sodium reabsorption, stimulation of the sympathetic nervous system, growth-promoting activity on vascular smooth muscle cells, and modulation of transmembrane cation transport. Epidemiological investigations have implicated sodium intake in the pathogenesis of hypertension. Because of the sodium-retaining effects of insulin, it has been postulated that insulin resistance with associated hyperinsulinaemia may be critical for the pathogenesis of salt-sensitivity in essential hypertensive subjects. Insulin resistance is present also in strains of rats with genetic hypertension that can be utilized as models to study the molecular mechanisms of this abnormality. In the present article, we summarize the current knowledge of the mechanisms of insulin resistance in rat models of arterial hypertension in which decreased sensitivity to insulin occurs and propose a rationale hypothesis that links insulin resistance with salt-sensitivity and hypertension.
Animals↗
The use of amikacin in the treatment of primary cutaneous mycobacteriosis due to Mycobacterium fortuitum.
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Adult↗
Different strategies for molecular differentiation of Mycobacterium bovis strains isolated in Sardinia, Italy.
Different genetic markers were used to analyze 22 Mycobacterium bovis strains isolated from cattle in Sardinia and one human isolate. IS6110 DNA fingerprinting differentiated the strains into six patterns, whereas with enterobacterial repetitive consensus sequence primers produced seven clusters. PCR ribotyping followed by digestion with HaeIII and PvuII produced five and seven patterns, respectively. PCR with the (GTG)5 oligonucleotide primer showed the best discriminatory power, generating eight clusters among the strains analyzed.
Animals↗
Differentiation of Vibrio alginolyticus strains isolated from Sardinian waters by ribotyping and a new rapid PCR fingerprinting method.
We investigated the usefulness of a novel PCR fingerprinting technique, based on the specific amplification of genomic regions, to differentiate 30 Vibrio alginolyticus strains isolated in Sardinian waters. The different profiles obtained were scanned and analyzed by a computer program in order to determine genetic relationships. The results were then compared with the patterns obtained by ribotyping with HindIII, KpnI, and XbaI restriction enzymes. PCR fingerprinting could differentiate the strains analyzed into 12 different patterns, whereas ribotyping with XbaI, which produced the highest number of patterns, generated only 7 different profiles. This study revealed the superior discriminative power of the proposed technique for the differentiation of related V. alginolyticus strains and the potential use of PCR fingerprinting in epidemiological studies.
Bacterial Typing Techniques↗
Molecular characterization and antibiotic susceptibilities of ocular isolates of Staphylococcus epidermidis.
Nineteen isolates of Staphylococcus epidermidis from patients with ocular infections were analyzed. Patients were selected in retrospect, by choosing cases in which S. epidermidis was the sole isolate. Twelve different patterns were obtained after hybridization with a probe with high-level homology to insertion sequences found in S. epidermidis. Susceptibilities to penicillin, methicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, vancomycin, and teicoplanin were determined. Six strains were resistant to three or more antibiotics.
Anti-Bacterial Agents↗
Identification and antibiotic susceptibility of coagulase negative staphylococci isolated in corneal/external infections.
AIMS: To identify and determine antibiotic susceptibility of coagulase negative staphylococci (CoNS) isolated from patients with chronic blepharitis, purulent conjunctivitis, and suppurative keratitis. METHODS: A retrospective review of all culture positive cases of chronic blepharitis, purulent conjunctivitis, and suppurative keratitis between July 1995 and December 1996 was performed. Cases in which CoNS were the sole isolates were analysed. Species identification was performed by using a commercially available standardised biochemical test system. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was determined by agar disc diffusion (Kirby-Bauer method). Teicoplanin resistance was confirmed by agar dilution. RESULTS: 42 Staphylococcus epidermidis, four S warneri, three S capitis, two S hominis, one each of S xylosus, S simulans, S equorum, and S lugdunensis were identified. 37 CoNS were penicillin resistant, 12 gentamicin resistant, 28 tetracycline resistant, 18 erythromycin resistant, four ciprofloxacin resistant, and one teicoplanin resistant (MIC, 32 microg/ml). In total, 16 strains were resistant to three or more antibiotics. CONCLUSION: Species of CoNS apart from S epidermidis may be isolated from patients with corneal and external infection. Antibiotic susceptibility of CoNS is unpredictable and multiresistant strains are common. As a result, antibiotic susceptibility testing should be performed in all cases of clinically significant ocular infections caused by CoNS.
Anti-Bacterial Agents↗
Identification of HIV patients with active pulmonary tuberculosis using urine based polymerase chain reaction assay.
BACKGROUND: Despite the increased dissemination of tuberculosis among HIV infected patients, the diagnosis is difficult to establish. Traditional microbiological methods lack satisfactory sensitivity. We have developed a highly sensitive and specific nested polymerase chain reaction (PCR) capable of detecting Mycobacterium tuberculosis DNA in urine specimens and have used this test to examine urine specimens from HIV patients with active pulmonary tuberculosis. METHODS: Urine specimens from 13 HIV infected patients with microbiologically proven active pulmonary tuberculosis, 10 AIDS patients with non-tuberculous mycobacterial infection (documented by blood culture), 53 AIDS patients with no evidence of mycobacterial disease, and 80 healthy subjects (25 with positive skin test to purified protein derivative) were tested for M tuberculosis using PCR, acid fast staining (AFS), and culture. RESULTS: Of the urine specimens from patients with active tuberculosis, all tested positive by PCR, two by culture, and none by AFS. No reactivity was observed in urine specimens from patients with non-tuberculous mycobacterial infection. Of the 53 AIDS patients without mycobacterial infection, one had a positive urine PCR. Normal subjects were all negative. CONCLUSIONS: Urine based nested PCR for M tuberculosis may be a useful test for identifying HIV patients with pulmonary tuberculosis.
AIDS-Related Opportunistic Infections↗
Post-infectious glomerulonephritis in a patient with Gemella haemolysans endocarditis.
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Diagnosis, Differential↗
Molecular characterization of Streptococcus equi subspecies equi isolated from an Ethiopian camel by ribotyping and PCR-ribotyping.
The aim of this study was to characterize a S. equi subspecies equi strain isolated from an Ethiopian camel by different molecular techniques (Ribotyping and PCR-Ribotyping). We compared the results obtained with those generated from two strains of the Pasteur Collection. The ribotyping showed the highest power of differentiation, distinguishing between the strains analyzed, whereas PCR-Ribotyping was able only to differentiate the camel isolate but not the strains from the Pasteur Collection. The application of this technique will be very useful to establish a clonal relationship among equine and camelids strains and help the prevention and cure of the equine and camel pathology.
Animals↗
Genotypic changes in DNA fingerprinting patterns of Mycobacterium tuberculosis strains from HIV-positive persons in Sardinia.
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DNA Fingerprinting↗
Increased serum lipoprotein(a) levels in patients with early renal failure.
BACKGROUND: Elevated serum lipoprotein(a) levels have been found in patients with end-stage renal disease and in patients undergoing dialysis, suggesting that this lipoprotein contributes to the increased cardiovascular risk seen in these patients. It is not known whether lipoprotein(a) levels are elevated in the early phases of renal disease. OBJECTIVE: To evaluate levels of lipoprotein(a) and other lipids and the prevalence of atherosclerotic disease in patients with early renal failure. DESIGN: Cross-sectional study. SETTING: Hypertension clinic of a university medical center. PATIENTS: 257 patients with normal renal function and 160 patients with early impairment of renal function (creatinine clearance, 30 to 89 mL/min per 1.73 m2 of body surface area). MEASUREMENTS: Renal function was assessed by 24-hour creatinine clearance, proteinuria, and microalbuminuria. Cardiovascular disease status was also assessed. Serum lipoprotein(a), lipids, apolipoproteins, and apolipoprotein(a) isoforms were measured. RESULTS: Age, blood pressure, and serum lipoprotein(a) levels were greater in patients with early renal failure than in those with normal renal function and were independently associated with the presence of decreased creatinine clearance. Serum lipoprotein(a) and creatinine clearance were inversely correlated. The prevalence of coronary artery, cerebrovascular, and peripheral vascular disease was greater in patients with early renal failure than in those with normal renal function. The frequency distribution of apolipoprotein(a) isoforms was similar in patients with normal and those with impaired renal function. CONCLUSIONS: Serum lipoprotein(a) levels are elevated in patients with early impairment of renal function and are associated with greater prevalence of cardiovascular disease. An inverse correlation between serum lipoprotein(a) level and creatinine clearance and a frequency distribution of apolipoprotein(a) isoforms similar to that of normal patients point to decreased renal catabolism as a probable mechanism of lipoprotein(a) elevation in patients with early renal failure.
Adult↗
Characterization of new insertion-like sequences of Enterococcus hirae and their dissemination among clinical Enterococcus faecium isolates.
Sequence analysis of different fragments that hybridized with a 4.5-kb EcoRI fragment originally cloned from Enterococcus hirae ATCC 9790 showed 66% homology to IS-like sequences found in staphylococci and lactococci. We tested several enterococcal ATCC strains and found that only E. hirae ATCC 9790 and Enterococcus faecium ATCC 19434 hybridized with the IS-like sequence. Moreover, we wanted to investigate the dissemination of this new IS among E. faecium strains. We analyzed 131 clinical E. faecium isolated in Italy and the USA for the presence of the IS and we found its presence in more than 63% of the isolates. The hybridization patterns obtained vary considerably between unrelated strains and allow further classification among ribotype-grouped species.
Base Sequence↗
Enterobacterial repetitive intergenic consensus sequences as molecular targets for typing of Mycobacterium tuberculosis strains.
The presence of enterobacterial repetitive intergenic consensus (ERIC) sequences was demonstrated for the first time in the genome of Mycobacterium tuberculosis; these sequences have been found in transcribed regions of the chromosomes of gram-negative bacteria. In this study genetic diversity among clinical isolates of M. tuberculosis was determined by PCR with ERIC primers (ERIC-PCR). The study isolates comprised 71 clinical isolates collected from Sardinia, Italy. ERIC-PCR was able to identify 59 distinct profiles. The results obtained were compared with IS6110 and PCR-GTG fingerprinting. We found that the level of differentiation obtained by ERIC-PCR is greater than that obtained by IS6110 fingerprinting and comparable to that obtained by PCR-GTG. This method of fingerprinting is rapid and sensitive and can be applied to the study of the epidemiology of M. tuberculosis infections, especially when IS6110 fingerprinting is not of any help.
Bacterial Typing Techniques↗
Microbiological diagnosis of tuberculosis: a comparison of old and new methods.
The aim of our study was to evaluate the diagnostic value of various methods widely used in microbiological diagnosis of tuberculosis: direct smear examination for acid-fast bacilli, cultural identification in Lowestein-Jensen (L-J) medium, the radiometric BACTEC 460 system, and Polymerase Chain Reaction (PCR). Three hundred and ninety-three clinical samples of sputum (375), gastric aspirate (3), pleural fluid (12) and urine (3) were taken from 125 patients hospitalized at our Institute for suspected pulmonary tuberculosis, between January 1995 and June 1997. On completion of diagnosis, 35 were found to be affected by active tuberculosis (30 pulmonary, 4 pleural and 1 urinary) and 90 by other non-tubercular diseases (pneumonia, lung cancer, non-tubercular pleural effusion, etc.). In our study, direct smear examination for acid-smear bacilli gave diagnostic value results of 88% and positive predictive value of 91.67%. Cultural identification in L-J and BACTEC 460 TB radiometric system media resulted in diagnostic values of 96.80% and 94.40%, respectively, and positive predictive values of 100% for both of them. Finally, One-Tube Nested-PCR, a variant which uses specific primers for the IS6110 insertion sequence specific for Mycobacterium tuberculosis, gave us 88.80% (91.43% sensitivity and 87.78% specificity) diagnostic value results, and 74.42% (11 false-positives) positive predictive value. On the basis of our results, we can affirm that PCR is a good method for microbiological diagnosis of tuberculosis, given its high sensitivity and specificity and unparalleled rapidity. However, the high number of false-positives that we found suggests that results obtained should be confirmed with BACTEC, which considerably reduces the time required for identification, and makes it possible to carry out an antibiotic assay rapidly.
Amino Acid Sequence↗