Biomedical subjects

M Clementi

Publications and source records attributed to M Clementi.

At least 55 records · Page 3Linked to original sources

PubMed2000

Prevalence of multiple dideoxynucleoside analogue resistance (MddNR) in a multicenter cohort of HIV-1-infected Italian patients with virologic failure.

We evaluated the prevalence of both Q151M and 6-bp insert at position 69 of RT region responsible for multiple dideoxynucleoside analogue-resistant (MddNR) HIV-1 variants in 177 patients who failed to respond to combination therapy. Patients had received protease inhibitors (PI) and/or nonnucleoside reverse transcriptase inhibitors (NNRTIs) after a long-term experience with nucleoside reverse transcriptase inhibitors (NRTIs) (including zidovudine monotherapy). Two of 177 patients (1.1%) showed the specific complex of Q151M mutation, while 4 (2.3%) had the 69 6-bp insert. Mutations that belong to the 151 set in the absence of the pivotal Q151M substitution were detected in as many as 3.9% of the patients. One patient exhibited a 69S [VG] insert that has not been previously phenotypically characterized. This HIV-1 isolate had high levels of resistance to all NRTIs except stavudine. MddNR is an emerging problem after sequential therapy with this class of compounds among HIV-1-infected patients. Either didanosine (ddI) or zidovudine (ZDV) monotherapy allowed the emergence of MddNR variants containing Q151M complex. Monotherapy with ZDV and ddI or subsequent treatments with various NRTI combinations were the common background in the patients with the 69 insert. The overall prevalence of MddNR (3.4%) in Italy is comparable with that observed in several other European countries (3.4%-6.5%). These data suggest that patients failed by NRTI regimens should be analyzed for the presence of both patterns of MddNR.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Quantitative evaluation of the recombinant HIV-1 phenotype to protease inhibitors by a single-step strategy.

OBJECTIVE: To develop and optimize a fast and quantitative recombinant strategy for evaluating the HIV-1 phenotype to protease inhibitors (PI). DESIGN AND METHODS: A non-replicative HIV-1 molecular vector (designated pdelta prodelta env) capable of expressing exogenous HIV-1 protease-encoding sequences was developed in this study. The HIV-1 protease sequences were amplified from either viral isolates or plasma samples (both from 21 HIV-1-infected individuals, 19 of whom were failing different anti-HIV-1 combination treatments) and cloned in the pdelta prodelta env backbone. The HIV-1 recombinant phenotype to PI was determined directly after transfection of viral chimeric clones by measuring protease activity and calculating a percentage sensitivity index (SI%; the ratio between the results from each clone and those from a PI-sensitive reference strain). RESULTS: The SI% values obtained from the recombinant clones paralleled the IC50 results of the viral isolates and documented different degrees of resistance and cross-resistance to PI, compatible, with few exceptions, with the respective genotype. Interestingly, an inverse correlation between SI% values and the presence of primary mutations for resistance to PI (P = 0.0038 and P = 0.0414, for indinavir and ritonavir, respectively) and a difference in SI% between samples harbouring an increasing number of mutations (indinavir, P = 0.022; ritonavir, P = 0.0466) were observed. CONCLUSION: The data substantiate the reliability of the novel strategy for a fast (5 day) quantitative evaluation of HIV-1 phenotype to PI, and indicate that this method may contribute to the understanding of mechanisms of virus resistance to PI.

Chimera↗

PubMed2000

Evaluation of the prenatal diagnosis of limb reduction deficiencies. EUROSCAN Study Group.

Ultrasound scans in the mid-trimester of pregnancy are now a routine part of antenatal care in most European countries. Using data from registries of congenital anomalies a study was undertaken in Europe. The objective of the study was to evaluate prenatal detection of limb reduction deficiencies (LRD) by routine ultrasonographic examination of the fetus. All LRDs suspected prenatally and all LRDs (including chromosome anomalies) confirmed at birth were identified from 20 Congenital Malformation Registers from the following 12 European countries: Austria, Croatia, Denmark, France, Germany, Italy, Lithuania, Spain, Switzerland, The Netherlands, UK and Ukrainia. These registries are following the same methodology. During the study period (1996-98) there were 709,030 births, and 7,758 cases with congenital malformations including LRDs. If more than one LRD was present the case was coded as complex LRD; 250 cases of LRDs with 63 (25.2%) termination of pregnancies were identified including 138 cases with isolated LRD, 112 with associated malformations, 16 with chromosomal anomalies and 38 non chromosomal recognized syndromes. The prenatal detection rate of isolated LRD was 24.6% (34 out of 138 cases) compared with 49.1% for associated malformations (55 out of 112; p<0.01). The prenatal detection of isolated terminal transverse LRD was 22.7% (22 out of 97), 50% (3 out of 6) for proximal intercalary LRD, 8.3% (1 out of 12) for longitudinal LRD and 0 for split hand/foot; for multipli-malformed children with LRD those percentages were 46.1% (30 out of 65), 66.6% (6 out of 9), 57.1% (8 out of 14) and 0 (0 out of 2), respectively. The prenatal detection rate of LRDs varied in relation with the ultrasound screening policies from 20.0% to 64.0% in countries with at least one routine fetal scan.

Adult↗

PubMed2000

Double-blind manometric assessment of two topical glyceryl trinitrate formulations in patients with chronic anal fissures.

BACKGROUND: Chronic anal fissure is a frequent and troubling condition, that may need surgical sphincterotomy for relief of symptoms. However, this approach may yield minor incontinence in up to 30% of cases. Interest has, therefore, recently increased in "chemical sphincterotomy" by using topical glyceryl trinitrate ointment. Unfortunately, there is, to date, no specific pharmaceutical preparation of such compound. AIMS: To compare, according to a randomized double-blind crossover study, the effects of a pharmaceutical preparation of a specific 0.2% glyceryl trinitrate ointment (PMF 303) and of the common preparation reported in the literature on the anal resting pressure in patients with anal fissure. PATIENTS AND METHODS: Twelve patients with chronic anal fissure (6 males and 6 females, age range 23-60 years] were recruited for the study. Two paired manometric studies were carried out at one-week intervals. After the basal anal pressure had been assessed, the patients were randomized to receive either one of the two preparations, and manometric measurements were repeated at 20, 40 and 60 minutes. RESULTS: No differences were found between anal resting pressure in the basal study. Both preparations were able to significantly decrease (p=0.001) anal pressure throughout the study period. No significant differences were found between the two preparations. CONCLUSIONS: PMF 303 is able to decrease anal pressure in patients with anal fissure, to a similar extent to the widely tested (galenic) literature preparation. Availability of a specific formulation for the treatment of this condition may be clinically useful.

Administration, Topical↗

PubMed2000

Absence of HHV-6 and HHV-7 in cerebrospinal fluid in relapsing-remitting multiple sclerosis.

OBJECTIVE: To contribute to clarifying the controversy on the association between Human Herpesviruses 6 and 7 (HHV-6, HHV-7) and multiple sclerosis (MS) studying patients with relapsing-remitting MS (RRMS) with or without evidence of disease activity (clinically or radiologically evaluated). MATERIAL AND METHODS: In 25 RRMS patients, 7 suspected MS patients and 9 patients with other neurological diseases, the following parameters were analysed: i) antibody titers (IgM and IgG) against HHV-6 by indirect immunofluorescence both in serum and cerebrospinal fluid (CSF) samples; ii) PCR-detection of HHV-6 DNA and HHV-7 DNA in CSF and HHV-6 DNA in peripheral blood mononuclear cells (PBMCs). MS patients in remission underwent a gadolinium-enhanced magnetic resonance imaging in proximity of sample collections. RESULTS: No viral DNA was found in any CSF sample, HHV-6 DNA frequency in PBMCs of MS patients and controls was not statistically different. Antibody titers against HHV-6 were comparable to those of the general population. Some 30.4% of MS patients were seronegative to HHV6. CONCLUSION: Our data suggest that there is no relationship between HHV-6 or HHV-7 and MS.

Adult↗

PubMed2000

Combined segregation and linkage analysis of inflammatory bowel disease in the IBD1 region using severity to characterise Crohn's disease and ulcerative colitis. On behalf of the GISC.

Inflammatory bowel disease (IBD) is a chronic relapsing disorder affecting the gastro-intestinal tract and is subdivided into two main subtypes: Crohn's disease (CD) and ulcerative colitis (UC). Although the aetiology of IBD is unknown, a strong genetic susceptibility is suggested and different candidate regions have been identified for both CD and UC. The IBD1 region on chromosome 16 has been confirmed to be important for susceptibility to CD, whereas conflicting evidence has been obtained for UC. We performed a combined linkage and segregation analysis in the identified IBD1 region on a sample of 82 extended families with IBD using a parametric method implemented in the computer program COMDS. This approach allows simultaneous evaluation of linkage while estimating the mode of inheritance and to include severity of the trait to characterise the CD and UC phenotypes. Our results are consistent with the presence of a major gene in the IBD1 region close to D16S408 involved in both UC and CD. Furthermore, our data support evidence that a single mutation in the gene leads more frequently to UC, whereas inheritance of two mutant alleles results in the more severe CD. In our study the IBD1 locus was found to have a major role in IBD predisposition in the Italian population.

Adult↗

PubMed2000

NF1 microdeletion syndrome: refined FISH characterization of sporadic and familial deletions with locus-specific probes.

Two familial and seven sporadic patients with neurofibromatosis 1-who showed dysmorphism, learning disabilities/mental retardation, and additional signs and carried deletions of the NF1 gene-were investigated by use of a two-step FISH approach to characterize the deletions. With FISH of YAC clones belonging to a 7-Mb 17q11.2 contig, we estimated the extension of all of the deletions and identified the genomic regions harboring the breakpoints. Mosaicism accounted for the mild phenotype in two patients. In subsequent FISH experiments, performed with locus-specific probes generated from the same YACs by means of a novel procedure, we identified the smallest region of overlapping (SRO), mapped the deletion breakpoints, and identified the genes that map to each deletion interval. From centromere to telomere, the approximately 0.8-Mb SRO includes sequence-tagged site 64381, the SUPT6H gene (encoding a transcription factor involved in chromatin structure), and NF1. Extending telomerically from the SRO, two additional genes-BLMH, encoding a hydrolase involved in bleomycin resistance, and ACCN1, encoding an amiloride-sensitive cation channel expressed in the CNS-were located in the deleted intervals of seven and three patients, respectively. An apparently common centromeric deletion breakpoint was shared by all of the patients, whereas a different telomeric breakpoint defined a deletion interval of 0.8-3 Mb. There was no apparent correlation between the extent of the deletion and the phenotype. This characterization of gross NF1 deletions provides the premise for addressing correctly any genotype-phenotype correlation in the subset of patients with NF1 deletions.

Chromosome Deletion↗

PubMed2000

Quantitative molecular analysis of virus expression and replication.

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Antiviral Agents↗

PubMed2000

Molecular epidemiology of an outbreak of fulminant hepatitis B.

A nosocomial outbreak of hepatitis B occurred among the inpatients of a hematology unit. Nine of the 11 infected patients died from fulminant hepatitis. An investigation was conducted to identify the source of infection and the route of transmission. Two clusters of nosocomial hepatitis B were identified. The hepatitis B virus (HBV) genome from serum samples of all case patients, of one HBsAg-positive patient with acute reactivation of the infection, and of eight acutely infected, unrelated cases was identified by PCR amplification of viral DNA and was entirely sequenced. Transmission was probably associated with breaks in infection control practices, which occurred as single events from common sources or through a patient-to-patient route, likely the result of shared medications or supplies. Sequence analysis evidenced close homology among the strains from the case patients and that from the patient with reactivation, who was the likely source of infection. Molecular analysis of viral isolates evidenced an accumulation of mutations in the core promoter/precore region, as well as several nucleotide substitutions throughout the genome. The sequences of all patients were compared with published sequences from fulminant and nonfulminant HBV infections.

Acute Disease↗

PubMed2000

Dominant role of host selective pressure in driving hepatitis C virus evolution in perinatal infection.

The dynamics of the genetic diversification of hepatitis C virus (HCV) populations was addressed in perinatal infection. Clonal sequences of hypervariable region 1 of the putative E2 envelope protein of HCV were obtained from four HCV-infected newborns (sequential samples spanning a period of 6 to 13 months after birth) and from their mothers (all samples collected at delivery). The data show that the variants detected between birth and the third month of life in samples from the four newborns were present in the HCV populations of their mothers at delivery. In the newborns, a unique viral variant (or a small group of closely related variants) remained stable for weeks despite active viral replication. Diversification of the intrahost HCV population was observed 6 to 13 months after birth and was substantially higher in two of the four subjects, as documented by the intersample genetic distance (GD) (P = 0.007). Importantly, a significant correlation between increasing GD and high values for the intersample K(a)/K(s) ratio (the ratio between anoffymous and synonymous substitutions; an index of the action of selective forces) was observed, as documented by the increase of both parameters over time (P = 0.01). These data argue for a dominant role of positive selection for amino acid changes in driving the pattern of genetic diversification of HCV populations, indicate that the intrahost evolution of HCV populations is compatible with a Darwinian model system, and may have implications in the designing of future antiviral strategies.

Amino Acid Sequence↗

PubMed2000

Evaluation of the prenatal diagnosis of neural tube defects by fetal ultrasonographic examination in different centres across Europe.

OBJECTIVE: Evaluation of prenatal diagnosis of neural tube defects by ultrasound examination in unselected populations across Europe. SETTING: Prenatal ultrasound units in areas that report to contributing congenital malformation registers. METHODS: All cases with a suspected or confirmed neural tube defect and delivered within the 30 month study period were identified from 18 Congenital Malformation Registers from 11 European countries. Data on the pregnancy, prenatal scans, outcome of pregnancy, and information on different screening policies for each country were analysed. RESULTS: 670766 deliveries occurred in the area covered by the registers during the study period. A neural tube defect was diagnosed at delivery in 542 cases. In 84% of these, the lesion was isolated (166 anencephaly, 252 spina bifida, 35 encephalocele). Of the 166 isolated cases with anencephaly, 96% were correctly identified prenatally; one was missed on scan, two were wrongly diagnosed, and four were not scanned (sensitivity 98%). 84% of the prenatal diagnoses were made before 24 weeks' gestation; 86% of isolated anencephalic pregnancies were terminated. Of the 252 cases of isolated spina bifida, 171 (68%) were correctly identified prenatally; 66% of these before 24 weeks' gestation. The diagnosis was missed on scan in 60 cases and 21 were not scanned (sensitivity 75%). The mean reduction in birth prevalence because of termination of pregnancy for spina bifida was 49% (range 6-100%). There was a wide variation between centres in prenatal detection rate (33-100%), termination of pregnancy of prenatally diagnosed cases (17-100%), and gestation both at diagnosis and termination of pregnancy. CONCLUSION: A high prenatal detection rate for anencephaly was reported by all registers. There is a large variation in prenatal detection and termination rates for spina bifida between centres, reflecting differences both in policy and culture.

Europe↗

PubMed2000

Lack of Chlamydia infection of the central nervous system in multiple sclerosis.

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Central Nervous System Bacterial Infections↗

PubMed2000

Evaluation of prenatal diagnosis of cleft lip with or without cleft palate and cleft palate by ultrasound: experience from 20 European registries. EUROSCAN study group.

Cleft Lip↗

PubMed1999

Neurofibromatosis type 1 growth charts.

Growth abnormalities such as macrocephaly and short stature have been described and are considered a consistent finding in neurofibromatosis type 1 (NF1), one of the most common autosomal dominant disorders in man. We present here a clinical study on the growth profile of a sample of NF1 patients collected through a population-based registry that covers three contiguous regions of North-East Italy (NEI-NF Registry). Auxometric traits of 528 NF1 patients have been measured with the aim of drawing growth charts for height, weight, and head circumference (OFC). Height velocity charts were based on a subset of 143 children who underwent multiple measurements. No differences in height were apparent between NF1 and normal subjects up to age 7 (girls) and 12 (boys) years; subsequently, the 50th centile of NF1 subjects tends to overlap with the 25th centile of normal subjects, and the 3rd centile is much lower in NF1 subjects than in normal subjects, mainly during adolescence. The negatively skewed distribution of height seems to indicate that height growth impairment affects only a proportion of NF1 subjects; height growth impairment does not seem related to disease severity. As for weight, our data suggest that slight overweight is a characteristic of adult NF1 subjects (mainly among males), independent of disease severity. Height growth velocity is normal during childhood for both sexes, whereas the pubertal spurt is slightly anticipated and reduced in NF1 boys but not in girls. Our data confirm previous observations that macrocrania affects most NF1 subjects; the shape of the head growth curve is similar in NF1 and normal girls, whereas NF1 boys present an OFC pubertal growth spurt much more pronounced and delayed than normal boys. The disproportion between OFC and height seems to be related to disease severity in boys but not in girls. Growth charts presented here can be useful in neurofibromatosis clinics for the identification of the effects of secondary growth disorders, for growth prognosis, and for the evaluation of the effects of a therapy such as GH therapy after radiotherapy for optic glioma.

Adolescent↗

PubMed1999

Defective nef alleles in a cohort of hemophiliacs with progressing and nonprogressing HIV-1 infection.

Deletion of the nef gene results in viral attenuation and confers protection against challenge with wild-type simian immunodeficiency virus in macaques. Regarding HIV-1 infection, a few long-term nonprogressors (LTNP) with nef deletions have been described. In this study, the nef genes of a group of seven LTNP and eight progressors, all belonging to the same cohort of infected hemophiliacs, were analyzed by cloning and sequencing from both virion RNA and peripheral blood mononuclear cell-associated proviral DNA. Defective nef sequences coexisted with full-length nef open reading frames in five of seven LTNP and two of eight progressors. The proportion of disrupted nef sequences within each individual was significantly higher in LTNP (ranging from 10 to 63%) than in progressors (ranging from 9 to 21%) (P = 0.013). Moreover, in-frame small deletions predicting to encode Nef were found in all RNA- and DNA-derived clones from one LTNP and four progressors. A chimeric virus in which the nef gene of NL4.3 was substituted with the nef allele containing the deletion of two alanines at position 49-50 found in two progressors showed a defective replicative capacity compared to NL4.3 virus. In summary, hemophiliacs with either progressing or nonprogressing HIV-1 infection are characterized by the presence of defective nef variants.

Adolescent↗

PubMed1999

6-Substituted benzopyrans as potassium channel activators: synthesis, vasodilator properties, and multivariate analysis.

During the last 10 years compounds have been discovered which can activate or block KATP channels. In particular, K channel activators (KCA) have been found to be smooth muscle relaxants with their main utility in hypertension and bronchodilation. In this paper we describe the synthesis of new KCA of the benzopyran type with a fixed 4-substituent and a systematic variation in the 6-position. The relaxant potency in rat aorta and trachea was used for biological characterization of the benzopyrans. In both biological test systems, they exhibit potency ranges of more than 3 log units. Structure-activity relationships are investigated by principal component analysis (PCA) and partial least-squares (PLS) analysis. Most striking outliers in an initial PLS analysis of the entire database were the unsubstituted 6-H compound 13 as well as 34 and 35. For the remaining set of 31 compounds, a 3-component PLS model explains the variance in biological activity to 81% in the aortic and to 82% in the tracheal test system. 6-Substituents influence affinity by a direct (presumably dipolar) interaction with the receptor site. According to the 2D-plot of the partial PLS weights, a strong electronegativity as well as high values for the integy moment and for the heat of formation in water dominate the first component; low values for substituent size (as defined by globularity or surface) are in addition favorable for high potency. High lipophilicity and low minimum energies of interaction dominate the second component. Chemical descriptors for the biological potency of the test set in rat aorta and rat trachea are very similar according to the almost identical projection of the Y-variables onto the X-component space.

Animals↗

PubMed1999

Methimazole embryopathy: delineation of the phenotype.

We report on a further case of congenital anomalies in a child exposed to methimazole during the first trimester of pregnancy (from first to seventh gestational week), and define a specific malformation pattern related to prenatal methimazole exposure and consisting of choanal and esophageal atresia, scalp defects, minor facial anomalies and psychomotor delay.

Abnormalities, Drug-Induced↗

PubMed1999

High vitamin A intake in early pregnancy and major malformations: a multicenter prospective controlled study.

The European Network of the Teratology Information Services (ENTIS) collected and evaluated data on 423 pregnancies exposed during the first 9 weeks of gestation to a "high" dose of vitamin A (10,000 IU per day or more). Data were collected prospectively; 394 women (93.1%) were followed by telephone interview up to the first few weeks after the expected date of delivery, using standardized procedures. The presence of major structural malformations, excluding chromosomal and genetic diseases, was evaluated in 311 infants exposed to a median daily dose of vitamin A of 50,000 IU per day (range, 10,000-300,000 IU per day; interquartile range, 25,000-60,000 IU per day). Three infants with a major malformation were reported: pulmonary stenosis, stenotic anus with fistula, and bilateral inguinal hernia. No congenital malformations were reported among 120 infants exposed to more than 50,000 IU per day of vitamin A. When the birth prevalence rate of major malformations in the study group was compared with two internal control groups of infants exposed to: 1) "high" vitamin A exposure later in pregnancy, and 2) nonteratogenic agent exposures, the rate ratio was, respectively, 0.28 (CI 95% interval, 0.06, 1.23) and 0.50 (CI 95% interval, 0.14, 1.76). The studied sample did not provide evidence for an increased risk of major malformations, associated with "high" vitamin A intake during the organogenetic period, higher than 2.76 above the control reference risk of 1.91% (power 80%, alpha 0.10).

Abnormalities, Drug-Induced↗