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Biomedical subjects

M Clementi

Publications and source records attributed to M Clementi.

At least 145 records · Page 8Linked to original sources
PubMed1994

Active hepatitis C virus infection in bone marrow and peripheral blood mononuclear cells from patients with mixed cryoglobulinaemia.

The presence of hepatitis C virus (HCV) genomic sequences was checked in plasma, liver, peripheral blood mononuclear cells (PBMC) and bone marrow cells from 11 patients with mixed cryoglobulinaemia positive for anti-HCV antibodies, and from 11 patients with chronic HCV hepatitis without serological evidence of cryoglobulinaemia. HCV RNA sequences were demonstrated by reverse transcription polymerase chain reaction in seven plasma samples, in six PBMC samples, and in seven bone marrow cell samples from the 11 cryoglobulinaemic subjects; otherwise, viral specific nucleic acids were detected in 10 plasma samples, in one PBMC sample, and in two bone marrow cell samples from the 11 patients with chronic hepatitis. The HCV replicative intermediate was evidenced in four of the six PBMC and in five of the seven bone marrow aspirate HCV RNA-positive samples. Analysis of subpopulations isolated from bone marrow and peripheral blood samples showed HCV RNA sequences in mononuclear cells belonging either the CD2+ subset or to the CD19+ subpopulation or to the adherent cells. Finally, we compared the nucleotide sequences of a large portion (-270 to -59) of the HCV 5'-untranslated region from five patients with mixed cryoglobulinaemia and from seven patients with chronic hepatitis without cryoglobulinaemia; the degree of heterogeneity, compared with the prototype HCV sequence, was similar in both groups. These findings from two groups of HCV-infected patients indicate that transient or permanent active HCV infection of bone marrow and PBMC is frequent in anti-HCV-positive patients with mixed cryoglobulinaemia, and suggest that extra-hepatic infection may play a major role in influencing the pathophysiology of this infection as well as the viral persistence.

Aged↗
PubMed1994

Presence of hepatitis C virus (HCV) genomic RNA and viral replicative intermediates in bone marrow and peripheral blood mononuclear cells from HCV-infected patients.

The cellular tropism of hepatitis C virus (HCV) was studied in vivo in samples from patients with persistent HCV infection. Plasma, liver, peripheral blood mononuclear cell (PBMC), and bone marrow cell (BMC) samples from 15 subjects positive for anti-HCV antibodies were tested for the presence of HCV RNA sequences by reverse transcription PCR. Virus-specific RNA sequences were found to be present in liver samples from all subjects (100%), in plasma samples from 13 of 15 patients (86.7%), in PBMC samples from 3 patients (20%), and in BMC samples from 9 (60%) of the 15 anti-HCV-positive patients enrolled in this study. The presence of the molecular intermediate of HCV replication (the negative-stranded HCV RNA) was evident in the two of the three PBMC and in five of the nine BMC HCV RNA-positive samples. Finally, we studied the nucleotide sequence of a large portion (-270 to -59) of the 5'untranslated region of HCV amplified from plasma samples of 12 of the 15 patients with and without HCV in BMCs; the degree of heterogeneity compared with the prototype HCV sequence was similar in both groups. The data principally indicate that HCV infection of PBMCs and BMCs is frequent in persistently infected patients, as shown by the occurrence of positive- and negative-stranded HCV RNA, thus suggesting the possibility of extrahepatic replication of HCV.

Adult↗
PubMed1994

Quantitation of hepatitis C virus genome molecules in plasma samples.

A competitive reverse transcription PCR (cRT-PCR)-based assay for the quantitative detection of hepatitis C virus (HCV) viremia was developed, optimized, and applied to the direct molecular analysis of clinical samples from nine patients with persistent HCV infection. As for other competitive PCR-based applications, this method consists of the reverse transcription and subsequent amplification of two RNA species in the same tube: the wild-type template (to be quantified) and a known amount of a modified synthetic template. These templates have identical primer recognition sites and very similar (but not identical) sizes, thus allowing direct detection of both template species after gel electrophoresis and ethidium bromide staining. The results obtained by this cRT-PCR application for testing clinical samples from HCV-infected patients mainly indicate that the competitive approach reaches the degree of sensitivity (fewer than 5 HCV RNA molecules per 100 microliters) necessary to evaluate viral load in all HCV-infected patients, independently of clinical conditions, and that this technique is flexible enough to quantify highly divergent levels of cell-free HCV genome copy numbers in biological samples. Interestingly, we observed a sample-to-sample variation in the loss of detectable HCV genome molecules in serum in comparison with that in plasma from the same patient, thus indicating that serum specimens, although widely used in the past few years for qualitative molecular investigation of HCV-infected patients, cannot be used to obtain reliable quantitative data on HCV viremia from these patients.

Artifacts↗
PubMed1994

Dynamics of molecular parameters of human immunodeficiency virus type 1 activity in vivo.

The dynamics of viral activity during different phases of human immunodeficiency virus type 1 (HIV-1) infection were investigated by competitive PCR methods. In particular, we studied the time course of three quantitative molecular parameters of viral activity (genomic RNA copy number in plasma and provirus and late HIV-1 transcript molecule copy numbers in peripheral blood CD4+ T lymphocytes) in untreated patients and patients treated with specific anti-HIV-1 compounds. The results shown here indicate that direct RNA parameters are quantitative molecular indices sensitive enough to be used for a more accurate evaluation of the natural history of this infection and that an indirect parameter, the mean transcriptional activity for each provirus in CD4+ T lymphocytes, may be important in studying this infection in vivo at the molecular level. A dramatic decrease of the indices was evident at seroconversion, but the quantitative values were virtually stable throughout the time the untreated patients were studied during the clinical latency phase. Furthermore, the results indicate that an early response to antiretroviral compounds is detected in most subjects as a decrease in the viral activity level.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Chronic liver disease and active hepatitis C virus infection in patients with antibodies to this virus.

AIMS: To assess the association between active hepatitis C virus (HCV) infection and liver damage in randomly selected patients with antibodies to the virus. METHODS: Thirty three consecutive subjects with serologically confirmed positivity for antibodies to HCV were studied for the presence of liver and circulating viral sequences by using the reverse transcription polymerase chain reaction (RT-PCR) and specific primers for the 5'-untranslated region (5'-UTR) of the HCV genome. Parallel clinical, biochemical, and histological investigations were carried out in all cases. RESULTS: A comparative virological and histological investigation showed the presence of molecular signs of active viral replication and different degrees of liver damage in all cases. Baseline values of liver and plasma samples from all the patients showed (with one exception) the presence of detectable HCV RNA sequences, despite alanine amino transferase activities being within normal values or within 1.5 times the upper limit of normal in 13 of them. Examination of percutaneous liver biopsy specimens showed the presence of confirmed liver damage (ranging from chronic persistent hepatitis to cirrhosis) in all 33 patients. CONCLUSIONS: Circulating HCV RNA sequences (a direct sign of active HCV infection) are associated with liver damage, even in the absence of clinical or biochemical signs of overt liver disease. Parallel molecular, histological, and clinical follow up of these patients is needed to understand precisely the natural history of HCV infection and for correct clinical management.

Base Sequence↗
PubMed1994

Vaginal micropapillary lesions are not related to human papillomavirus infection: in situ hybridization and polymerase chain reaction detection techniques.

The objective of this study was to assess the human papillomavirus DNA presence in vaginal papillary lesions, with particular regard to micropapillomatosis to better define their clinical significance. Prospective study: the study population was composed of 62 women who were recruited consecutively from the Colposcopy Centre of the Ancona University, Department of Obstetrics and Gynecology, on the grounds of vaginal papillomatosis or/and typical acuminata warts. Biopsies for routine histology, and for human papillomavirus (HPV) DNA detection by means of in situ hybridization and polymerase chain reaction (PCR) were taken from the papillary lesions and from 24 healthy women, who were selected as controls. Macroscopically, vaginal micropapillomatosis was ascertained in 51 cases (82.3%), while in 11 cases (17.7%) the colposcopic diagnosis was condyloma acuminatum. During in situ hybridization, HPV DNA positivity was observed in 8 (9.4%) out of 85 samples of squamous papillae and in 11 (64.7%) out of 17 samples of condylomata; in control specimens, HPV DNA was detected in 2 (8.3%) out of 24 bioptic samples. The correspondence between in situ hybridization and PCR was 96.1%, with 17.4% more diagnosis obtained by PCR. Vaginal micropapillomatosis may be regarded as a variation in the normal anatomy of the lower genital tract without any significant relationship with HPV infection, and as a lesion easily distinguishable from condylomata acuminata by clinical examination alone.

Adolescent↗
PubMed1993

Is visual field reduction a component manifestation of osteopathia striata with cranial sclerosis?

A girl with fully expressed osteopathia striata with cranial sclerosis (OS) was also found to have a contraction of the two visual fields, a sign never previously described in OS syndrome. We suggest that the visual field defect is a component manifestation of OS syndrome, whose pathogenesis is represented by distortion of the optic canal and narrowing of the optic foramina.

Bone Diseases↗
PubMed1993

Omphalocele and gastroschisis: a collaborative study of five Italian congenital malformation registries.

During 1984-1989, 116 cases of omphalocele and 42 cases of gastroschisis were detected among 736,760 consecutive births in the area covered by five Italian congenital malformation registries. The prevalence rate was 1.6 per 10,000 for omphalocele and 0.6 per 10,000 for gastroschisis. Three additional cases were detected among spontaneous abortions, giving a total of 117 cases of omphalocele and 44 of gastroschisis. No variations in prevalence rates were observed among registries. A cluster of omphalocele was found in 1989 in Firenze. All cases were sporadic except for one infant with two sibs with Beckwith-Wiedemann syndrome. A predominance of male infants was observed for both defects. This study confirms the very young maternal age for isolated gastroschisis as compared to that for omphalocele and controls. Birth weight and the percentage of small-for-date is different among isolated gastroschisis, omphalocele and controls. Associated anomalies occurred in 45 cases of omphalocele and 11 cases of gastroschisis. Our data confirm the association of omphalocele with trisomies 13 and 18. Twelve cases of omphalocele and gastroschisis with associated limb defects were classified as limb body wall complex. The possible differences in etiopathology between omphalocele and gastroschisis, both isolated and associated, are discussed.

Abnormalities, Multiple↗
PubMed1993

Trans-activation of epidermal growth factor receptor gene by the hepatitis B virus X-gene product.

The expression of the cellular gene coding for the epidermal growth factor (EGF) receptor (EGF-R) was assayed in the presence of hepatitis B virus (HBV) gene expression under different experimental conditions in human hepatoma-derived cells. First, transfection experiments of the well-differentiated HepG2 human hepatoma cell line using different expression vectors of the HBV X-region demonstrated that the X-gene product is capable of inducing EGF-R gene overexpression; in addition, by using a stable in vitro expression system for HBV, it was shown that EGF-R gene expression in these cells is greater than in the uninfected parent cells, and that this results in a three-fold increase in 125I-EGF binding. Finally, a CAT-expression assay was performed, indicating that regulatory regions of the EGF-R-gene are target sequences for X-protein trans-activation.

Carcinoma, Hepatocellular↗
PubMed1993

Heritability of myopic refractive errors in identical and fraternal twins.

The existence of a visual feedback control of eye growth in humans is controversial, as the contributions of genetic and environmental factors are still unknown. To evaluate the heritability of refractive defects, we measured ocular refraction in 19 monozygote and 20 dizygote twin pairs (mean age 5 years). Monozygosity was ascertained by a common chorion, similarity of somatic traits, and identical dermatogliphes and was confirmed in myopes by blood marker diagnosis. Ocular refractive defects and axial length were evaluated by cycloplegic autorefractometry and biometry. By comparing identical and fraternal twins heritability of refractive defects was estimated to be 0.08-0.14; this low value indicates that the observed variability in refractive errors is nongenetic in origin. Three monozygote pairs were anisomyopic; differences between eyes in identical twins were related to the increased axial length of myopic eyes. In one eye, myopia was attributed to visual deprivation induced by a congenital cataract, while in five eyes it was correlated directly to the degree of astigmatic defects. The discordant axial length observed in monozygote twins is nongenetic. In agreement with previous findings reported in the literature, it is proposed that visual impoverishment of retinal images may play an early regulatory role in postnatal eye growth.

Blood Grouping and Crossmatching↗
PubMed1993

D8S7 is consistently deleted in inverted duplications of the short arm of chromosome 8 (inv dup 8p).

Ten patients with inverted duplication of 8p (inv dup 8p) were studied with cytogenetic, biochemical and molecular techniques. The duplication for the region 8p12-p22 was always associated with a deletion of the locus D8S7 (mapped in 8p23.1) as demonstrated with the probe pSW50 by both in situ hybridization and Southern blot. Restriction fragment length polymorphisms detected by probes pSW50 (1 case) and by pG2LPL35 (locus LPL) (two cases) were informative as to a maternal origin of the anomaly. The activity of glutathione reductase, whose gene maps in the duplicated region at 8p21.1, was increased in all patients. The recognizable phenotype of inv dup 8p includes neonatal hypotonia, prominent forehead, large mouth with everted lower lip, abnormally shaped large ears, brain malformations and severe mental retardation. Our findings indicate that the chromosome rearrangement is homogeneous at least for the presence of the deletion and support the hypothesis of a common mechanism of origin.

Abnormalities, Multiple↗
PubMed1993

[Animal experimentation in radiology. Objectives, organizational and ethical problems].

The contribution of biomedical sciences to the scientific breakthroughs in the last years has benefitted also by experiments on animals. As for diagnostic imaging, the use of new contrast media for angiography, CT and MRI makes it necessary, according to the law, to perform preliminary animal studies to test efficacy, pharmacokinetics and pharmacodynamics of the contrast agents. Experimental animal studies of clinically well-established contrast agents are also justified by the need to implement new imaging modalities. The close relationship between medical research and animal experimentation has awakened public opinion, as well as the researchers themselves, to the ethical and legal problems related to animal testing. This paper reports on the regulations which are currently in use in this field.

Animals↗
PubMed1992

A novel procedure for quantitative polymerase chain reaction by coamplification of competitive templates.

A method is described for the absolute quantification by polymerase chain reaction (PCR) of nucleic acids present in low abundance. The method entails the addition to the sample of competitor DNA molecules that share the same sequence as the amplified target (including primer recognition sites), except for a 20-bp insertion in the middle, which allows easy resolution by gel electrophoresis (competitive PCR). Among the advantages of competitive PCR is that any predictable or unpredictable variable that affects amplification has the same effect on both target and competitor species and that the final ratio of amplified products reflects exactly the initial rate of targets, rendering the reaction independent of the number of amplification cycles. An easy and reliable method for the construction and quantification of competitive templates obtained as recombinant PCR products was developed. The technique was used for the absolute quantification of human genomic DNA with primers from a single copy, subtelomeric region of chromosome 19.

Base Sequence↗
PubMed1992

Lack of detectable human T-cell lymphotropic virus type I sequences in samples from multiple sclerosis patients.

Recently, inconclusive results have followed the early data on the possible association between multiple sclerosis (MS) and human T-cell lymphotropic virus type I (HTLV-I) infection. For this reason, we examined this hypothesis using the polymerase chain reaction (PCR) to study samples of differing origin from Italian MS patients. In particular, we developed a systematic analysis of paraffin-embedded brain white matter from histologically defined lesions of 14 MS patients using PCR and primer sets specific for HTLV-I sequences; additionally, cerebrospinal fluids (CSFs) from 12 patients and peripheral blood mononuclear cells (PBMCs) from subjects at the early and late phase of the disease were investigated for free HTLV-I virions and specific proviral sequences, respectively. In agreement with some groups who reported lack of HTLV-I sequences in PBMCs of MS patients but in clear contrast with others, we failed to detect specific viral sequences using this broad approach.

Base Sequence↗
PubMed1992

Clinical anophthalmia: an epidemiological study in northeast Italy based on 368,256 consecutive births.

We describe an epidemiological and clinical study of Clinical Anophthalmia in a population of consecutive live and stillborns enrolled in a hospital based registry of congenital malformations in Northeast Italy during the period from 1981 to 1989; 22 cases were detected among 368,256 births yielding a birth prevalence of 0.60 per 10,000 (95% CI 0.34-0.84); 20 cases were associated with at least one other major malformation. Malformation syndrome, association, or sequence was diagnosed in 13, while a non-recognizable multiple defect pattern was observed in 7/20 (35%). A chromosomal anomaly was present in eight syndromic cases. No significant trend over time, nor space or time clusters, were detected. As most CAn cases are associated with other anomalies recognizable by ultrasound, a decreasing trend in its prevalence at birth is expected in the future.

Abnormalities, Multiple↗