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Biomedical subjects

M Colombo

Publications and source records attributed to M Colombo.

At least 37 records · Page 2Linked to original sources
PubMed2000

Restricted immune responses lead to CNS demyelination and axonal damage.

Although autoreactive T-cells have a pivotal role in initiating the inflammatory process in experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS), recent evidence suggests a relevant role for autoantibodies specific for myelin proteins as well. To examine the role of B-cells in the cerebrospinal fluid of patients with MS, we analyzed the V(H) gene usage in ten MS patients by PCR technologies. Analysis of HCDR3 length revealed an oligoclonal accumulation of B-cells. Sequence analysis of the V(H)3 and V(H)4 gamma transcripts of two MS individuals demonstrated that this accumulation was related to the expansion and somatic diversification of a limited groups of B-cell clones. These findings are indicative of a chronic and intense antigenic stimulation occurring in the CNS. Animal models, such as EAE, are of particular importance in order to elucidate the pathogenetic effector mechanisms in autoimmune demyelination. In a non-human primate model of EAE, we describe that the immunodominant T-cell epitope is presented exclusively by a monomorphic DRB1 allele, suggesting that susceptibility to EAE may be linked to this unique restriction and, therefore, providing a possible mechanism for MHC linkage to diseases. Moreover, we report on the presence of inflammation, sharp demyelination and axonal damage in EAE induced with whole myelin as well as with recombinant myelin oligodendrocyte glycoprotein (MOG), but not with myelin basic protein alone. The presence of axonal pathology was supported by immunohistochemistry with anti-amyloid precursor protein and anti-non phosphorilated neurofilaments monoclonal antibodies within early active demyelinated plaques. These findings suggest that axonal damage may be an early event in the pathogenesis of autoimmune demyelinating diseases of the CNS and highlights the importance of animal models in which therapies targeting repair and axonal survival may be exploited.

Animals↗
PubMed2000

Accumulation of clonally related B lymphocytes in the cerebrospinal fluid of multiple sclerosis patients.

The accumulation of B lymphocyte clones in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and patients with other neurological disorders was investigated using PCR technologies. Oligoclonal B cell accumulations were detected in 10 of 10 MS patients, but only in 3 of 10 of the patients with other neurological disorders. Analyses of the Ig V(D)J sequences on the CSF from MS patients disclosed that VH3 and VH4 genes were extensively mutated compared with germline sequences. Moreover, a substantial proportion of the molecular clones analyzed shared the same third CDR of the H chain variable region gene (HCDR3) and the same VH genes, albeit with different numbers and locations of point mutations, thus indicating an ongoing process of intraclonal diversification. A larger number of clonally related VH sequences could be obtained by using a VH3 gene-specific PCR so that genealogical trees depicting the process of diversification could be drawn. Analyses of the Ig V(D)J from the CSF of a patient with viral meningitis and oligoclonal B cell accumulations revealed that VH3 genes were extensively mutated. However, no intraclonal diversification could be observed even using VH3 gene-specific PCR methodologies. Clone-specific PCR and sequencing was used to detect the V(D)J found in the CSF of one MS patient in the PBL of the same patient. Only 1/3 of the V(D)J sequences investigated could be demonstrated in the PBL, indicating that the V(D)J genes utilized by B cells in the CSF are much less represented in the PBL. Collectively, the data suggest that in MS there is a compartmentalized clonal expansion.

Adolescent↗
PubMed2000

Is the avian hippocampus a functional homologue of the mammalian hippocampus?

The effects of hippocampal lesions on the processing and retention of visual and spatial information in birds and mammals is reviewed. Both birds and mammals with damage to the hippocampus are severely impaired on a variety of spatial tasks, such as navigation, maze learning, and the retention of spatial information. In contrast, both birds and mammals with damage to the hippocampus are not impaired on a variety of visual tasks, such as delayed matching-to-sample, concurrent discrimination, or retention of a visual discrimination. In addition, both birds and mammals with hippocampal damage display impairments in the acquisition of an autoshaped response, as well as alterations in response suppression. These findings suggest that the avian hippocampus is a functional homologue of the mammalian hippocampus, and that in both birds and mammals the hippocampus is important for the processing and retention of spatial, rather than purely visual information.

Animals↗
PubMed2000

Distribution of catabolic pathways in some hydrocarbon-degrading bacteria from a subsurface polluted soil.

Enrichment cultures on naphtha solvent were used to select aromatic hydrocarbon-degrading bacteria from a BTEX (benzene, toluene, ethylbenzene, xylene)-contaminated subsoil obtained from beneath a paint factory located in Milan, Italy. Fifteen isolated strains were studied for their different biodegradative capacities. Among these, 13 were able to grow on naphtha solvent. Ten were identified as Pseudomonas putida and three as Pseudomonas aureofaciens. Two other degraders were identified as Pseudomonas aeruginosa and Alcaligenes xylosoxidans subsp. denitrificans. Further molecular characterization of the isolates was carried out by randomly amplified polymorphic DNA analysis to ascertain that all the studied strains belonged to different haplotypes. The isolates were characterized for the presence of genes encoding for toluene dioxygenase, xylene monooxygenase and catechol 2,3-dioxygenase by polymerase chain reaction analysis and by Southern analysis. P. putida strain CM23, which showed homology with xylA,M, xylE and todC1C2BA genes, possessed multiple pathways which enabled the strain to grow on benzene, toluene and m-xylene.

Alcaligenes↗
PubMed2000

Prevalence and risk factors for the presence of serum cryoglobulins in patients with chronic hepatitis C.

To assess the prevalence and risk factors for cryoglobulinaemia associated with hepatitis C virus (HCV) infection, we studied 360 consecutive patients with chronic hepatitis C (191 men, median age 57 years; 86 [24%] with cirrhosis). One-hundred and sixty-eight (47%) had circulating cryoglobulins (mean levels 208 +/- 256 mg l-1), predominantly of type III (80%; and 20% type II). Cryoglobulins were more common in women than in men (56% vs 39%, P=0.001) and in patients with cirrhosis than in those with chronic hepatitis (57% vs 43%, P=0.024). Cryoglobulinaemic patients more frequently had high levels of serum immunoglobulin M (IgM) (57% vs 30%, P=0.001), immunoglobulin G (IgG) (84% vs 70%, P=0.002) and rheumatoid factor (45% vs 16%, P=0.001); low levels of serum C3 (15% vs 4%, P=0.001) and C4 (51% vs 26%, P=0.001); and low numbers of platelets (21% vs 12%, P=0.018), than patients without cryoglobulins. The presence of cryoglobulins was not correlated with hepatitis duration (cryopositives, 12 +/- 7 years; cryonegatives, 11 +/- 8 years) or HCV genotype (HCV 1b, 48% vs 53%; HCV 2a, 35% vs 29%, cryopositive vs cryonegative patients respectively). By multivariate analysis, female gender (odds ratio [OR] 1.675; confidence interval [CI] 1. 055-2.661), elevated serum IgM (OR 2.296; CI 1.438-3.665), IgG (OR 1. 952; CI 1.114-3.422), rheumatoid factor (OR 3.213; CI 1.889-5.465) and low C4 (OR 1.859; CI 1.138-3.038) could reliably predict the presence of cryoglobulins. When the pathogenic variables IgG, rheumatoid factor and C4 were excluded from analyses, only levels of serum cholinesterase activity < 4500 U independently predicted (OR 3. 663, CI 1.258-10.184) the presence of cryoglobulins. Fifty per cent of the patients with chronic hepatitis C circulated cryoglobulins, with preference for those with a greater impairment of liver function, as revealed by serum cholinesterase activity.

Adult↗
PubMed2000

Hepatitis C is more severe in drug users with human immunodeficiency virus infection.

Drug users with chronic hepatitis C virus (HCV) infection are frequently co-infected with human immunodeficiency virus-1 (HIV-1), but it is still not clear whether HIV-1 worsens the natural history of hepatitis C. To investigate this, we conducted a multicentre observational study in 163 drug addicts with histologically documented hepatitis C, 92 of whom were also infected with HIV-1: 25 (27%) were CDC stage II, 53 (58%) were CDC stage III and 14 (15%) were CDC stage IV. Eighty-eight (54%) patients had chronic hepatitis (CH) with minimal activity, 28 (17%) had CH with moderate activity, 40 (25%) had CH with severe activity and seven (4%) had active cirrhosis. Twenty-one HIV-negative patients and 15 HIV-positive patients admitted to alcohol abuse (29% vs 16%, P=0.0665). Liver disease was more severe in HIV-positive patients than in HIV-negative ones (P=0.0198): 34 HIV-positive patients and 13 HIV negatives had severe CH and cirrhosis. These two severe liver diseases were seen more often in HIV-positive patients with a history of alcohol abuse than in HIV-negative patients (10 out of 16 vs seven out of 21). Age, alcohol abuse and distribution of the histological categories of liver disease were statistically different in HIV-infected and HIV-uninfected patients. Multivariate analysis showed that age, alcohol abuse and serum antibodies to HIV were independently associated with severe CH or cirrhosis. Thus, HIV may enhance the risk of severe liver disease in drug users with hepatitis C, independently of the degree of immune dysfunction. Alcohol abuse may contribute independently, aggravating the cause of HCV-dependent liver disease.

Adult↗
PubMed2000

Sustained response to interferon-alpha2a monotherapy of young blood donors with minimal-to-mild chronic hepatitis C. The Donor Surveillance Study Group.

Subjects with minimal-to-mild chronic hepatitis C may suffer long-term consequences of hepatitis C virus (HCV) infection. Nonetheless, they are not candidates for antiviral treatment, mainly because little data are available concerning the efficacy and safety of therapy. Thirty-two HCV RNA positive individuals aged 18-45 years, who had a histological activity index score < or = 8 and alanine aminotransferase (ALT) levels < or = 1.5 times lower than the normal limit for at least 1 year, were prospectively enrolled among a cohort of 35358 candidate blood donors, and treated with 4.5 mega units (MU) of recombinant interferon-alpha2a (IFN-alpha2a) thrice weekly for 6 months, and for an additional 6 months if a virological response was observed. Twelve months after the completion of treatment, 13 of 31 evaluable patients were HCV RNA negative, accounting for a sustained response rate of 42%. Patients without fibrosis had a lower response rate than those with mild fibrosis (two of 14 vs 11 of 17; P=0.012). In responders, median aminotransferase levels were significantly lower after therapy than before (11.04 +/- 3.98 vs 27.3 +/- 12.32 U l-1, respectively; P < 0. 005). When the analysis was limited to the six responders whose pretreatment aminotransferase levels were consistently normal, this difference was still significant (9.33 +/- 4.12 vs 20.58 +/- 6.73 U l-1; P=0.002). In conclusion, a durable suppression of viraemia can be obtained by IFN monotherapy in a relatively high proportion of young subjects with minimal-to-mild chronic hepatitis C, especially when portal fibrosis is found on liver biopsy. The disappearance of viraemia always leads to a reduction in the degree of hepatocellular necrosis.

Adolescent↗
PubMed2000

Detection of genes for alkane and naphthalene catabolism in Rhodococcus sp. strain 1BN.

Rhodococcus sp. 1BN was isolated from a contaminated site and showed various biodegradative capabilities. Besides naphthalene, strain 1BN degraded medium- (C6) and long-chain alkanes (C16-C28), benzene and toluene, alone or when the hydrocarbons were mixed in equal proportions. The nucleotide sequence of an alk polymerase chain reaction (PCR) fragment revealed a 59% nucleotide homology to the Pseudomonas oleovorans alkB gene. The nar fragments were highly homologous to genes coding for large and small subunits of cis-naphthalene 1,2-dioxygenase (narAa and narAb) and to cis-naphthalene dihydrodiol dehydrogenase (narB) from other rhodococci. The oxidation of indene to cis-(1S,2R)-1,2-dihydroxyindan by toluene-induced cells allows to hypothesize that strain 1BN also carries a toluene dioxygenase-like system.

Alkanes↗
PubMed2000

Hepatocellular carcinoma in patients with HCV.

In most Western countries hepatitis C virus (HCV) is a common risk factor for hepatocellular carcinoma (HCC). Many HCCs are multifocal in origin, but HCC may also grow as a single hepatic nodule for years before generating satellite or distant tumours. HCV may promote cancer through cirrhosis, which is often associated with HCV-related HCC, but it might also have oncogenic properties by interacting with cellular genes that regulate cell growth and differentiation. Treatment of patients with chronic hepatitis C using interferon might attenuate HCC risk, particularly in those who respond to therapy. Many patients whose cancer is detected early have been successfully treated by liver transplantation and have shown significantly prolonged survival. This is less often achieved with hepatic resection or regional therapies, which may indeed destroy small tumours, without affecting the complications of portal hypertension. Screening remains the only realistic approach for improving the treatment of HCC patients, but its cost-effectiveness is uncertain.

Carcinoma, Hepatocellular↗
PubMed2000

High prevalence of TT virus (TTV) in naive chimpanzees and in hepatitis C virus-infected humans: frequent mixed infections and identification of new TTV genotypes in chimpanzees.

A recently discovered DNA virus, TT virus (TTV), is prevalent in humans. In the present study, the genetic heterogeneity of TTV was evaluated in hepatitis C virus (HCV)-infected patients and in chimpanzees. TTV DNA was detected by PCR in serum samples from all ten HCV-infected patients studied; at least five major TTV genotypes, all previously identified in humans, were recovered. Eight patients were infected with multiple variants of TTV. TTV DNA was detected by PCR in serum samples from 11 (65%) of 17 naive chimpanzees bred in captivity; a persistent infection was present in three of six animals. At least five chimpanzees were infected with more than one TTV variant. Detection of TTV DNA in chimpanzee faecal samples suggests the possibility of faecal-oral transmission. Phylogenetic analysis of ORF1 sequences amplified from chimpanzees identified three major genotypes which had not previously been recognized in humans.

Amino Acid Sequence↗
PubMed2000

Randomised comparison of Burch colposuspension versus anterior colporrhaphy in women with stress urinary incontinence and anterior vaginal wall prolapse.

OBJECTIVE: To compare the Burch colposuspension and the anterior colporrhaphy in women with both stress urinary incontinence and advanced anterior vaginal wall prolapse (cystocele). DESIGN: Prospective randomised study. SETTING: Secondary referral centre, Urogynaecology Unit, San Gerardo Hospital, Monza, Italy. SAMPLE: Seventy-one women undergoing surgery for primary genuine stress incontinence and concurrent grade 2 or 3 cystocele (descending at or outside the vaginal introitus). METHODS: Full urodynamic investigation performed pre-operatively and repeated six months after surgery. Clinical follow up continued for 8 to 17 years. MAIN OUTCOME MEASURES: Subjective (patient history) and objective (negative stress test result) cure of stress incontinence. Assessment of cystocele recurrence. RESULTS: Thirty (86%) of the 35 evaluable women who had the Burch colposuspension and 17 (52%) of the 33 evaluable women who had the anterior colporrhaphy were subjectively cured (OR 5.6, 95% CI 1.6 to 21.6; P = 0.005). Objective cure rates were 74% (26 of 35) and 42% (14 of 33), respectively (OR 3.9, 95% CI 1.3 to 12.5; P = 0.02). A recurrent cystocele of grade 2 or 3 with or without prolapse at other vaginal sites was recorded in 34% (12 of 35) and 3% (1 of 33) of women, respectively (OR 16.7, 95% CI 2.0 to 368.1; P = 0.003). CONCLUSIONS: The Burch colposuspension was better in controlling stress incontinence but it lead to an unacceptable high rate of prolapse recurrence. The anterior colporrhaphy was more effective in restoring vaginal anatomy but it was accompanied by an unacceptable low cure rate of stress incontinence. Neither of the two operations is recommended for women who are suffering from a combination of stress incontinence and advanced cystocele.

Female↗
PubMed2000

Pharmacology of cizolirtine: a new analgesic agent.

Cizolirtine citrate (E-4018) is a new analgesic agent with antinociceptive activity against phenylquinone (ED50 33.7 mg/kg) and acetic acid (ED50 24.4 mg/kg) in mice, against acetic acid in rats (ED50 21.3 mg/kg) and in the plantar test (ED50 26.8 mg/kg). It demonstrated antinociceptive activity in the tail-pinch and tail-flick tests (ED50s of 68.0 and 46.0 mg/kg, respectively), in both phases of the formalin test (ED50 13.8 and 2.31 mg/kg), and in the capsaicin test (ED50 7.14 mg/kg). Cizolirtine does not inhibit prostaglandin biosynthesis, it is not a ligand for opioid receptors, it does not have antiinflammatory or ulcerogenic activity, it has some antipyretic activity and shows no affinity for alpha 2-adrenergic receptors, but its analgesic effect was modified by idazoxan and by desipramine. Recent studies have shown that the analgesic effect of cizolirtine could be related, at least partially, to an inhibition of spinal substance P release.

Analgesics↗
PubMed1999

TT virus is present in a high frequency of Italian hemophilic patients transfused with plasma-derived clotting factor concentrates.

The prevalence of the blood-borne TT virus (TTV) in Italian hemophiliacs treated with different preparations of factor VIII was determined. Of the 178 hemophilic patients (mean age, 29 years), TTV-DNA was found in 123 (69%), in comparison to 22 of 100 (22%) blood donors (P <.0001). Of the 123 patients who tested positive for TTV, significant numbers were also infected with human hepatitis viruses and/or human immunodeficiency virus (HIV): 31% had TTV and hepatitis C virus (HCV), 22% had TTV, and at least 2 of the 4 known human blood-borne viruses tested, whereas 15% had TTV alone. The risk of acquiring TTV alone was only slightly higher in recipients of unmodified plasma factor concentrates (78%, odds ratio, 1.24; 95% confidence interval [CI], 0.27 to 5.79) than in patients treated with virus inactivated concentrates (67%), whereas the risk was significantly lower in recipients of recombinant factors (11%, odds ratio, 0.09; 95% CI, 0.01 to 0.52). Serum alanine aminotransferase (ALT) levels were elevated in 2 of 27 patients (7%) with TTV alone compared with 43 of 56 patients (77%) coinfected with TTV and HCV and compared with 16 of 21 patients (76%) with HCV alone. Taken together, these results indicate that TTV frequently infects Italian hemophiliacs treated with plasma-derived factor VIII concentrates, both unmodified and virus-inactivated. Our results do not suggest a causal effect of TTV on chronic liver disease in these patients.

Adolescent↗
PubMed1999

High prevalence of multinodular hepatocellular carcinoma in patients with cirrhosis attributable to multiple risk factors.

To see whether or not there is an association between the cause of cirrhosis and the number of hepatocellular carcinoma (HCC) nodules, we analyzed 178 consecutive patients in whom HCC was detected during a prospective screening by abdominal ultrasound (US). The relevant information was obtained from the database of the screening programs operating at four hospitals in the Milan area. One hundred twenty-nine (72%) patients had a single tumor nodule detected by US and 49 (28%) patients had multinodular disease. Ninety-eight (55%) patients had normal serum values of alpha-fetoprotein (AFP). Tumor staging with biphasic computed tomography (CT) scan or hepatic arteriography with lipiodol revealed that 101 (57%) patients had single tumor nodules and 77 (43%) patients had more than one HCC nodule. After staging, multinodular HCC was more common in patients with multiple risk factors than in the hepatitis C virus (HCV) carriers (56% vs. 38%, P =.05). Interestingly, single tumors were as common in the 126 patients undergoing 6-month interval screening as in the 52 patients who were studied at yearly intervals. The former patients, however, had more small tumors than the latter ones (91% vs. 74%, P =.04). The 22 patients who were alcohol abusers had normal levels of serum AFP more often than the hepatitis B virus (HBV) or HCV carriers or those with multiple risk factors (86% vs. 57%, P <.04; vs. 47%, P <.002; vs. 52%, P <.006, respectively). We concluded that multinodular HCC was underdetected by real time US; it prevailed among patients with multiple risk factors. In these patients, screening with US exams every 6 months may be inadequate for early detection of liver cancer.

Alcoholism↗
PubMed1999

Efficacy of double intrauterine insemination in controlled ovarian hyperstimulation cycles.

OBJECTIVE: To investigate the effectiveness of double IUI and to determine the optimal timing of IUI in relation to hCG administration. DESIGN: Prospective randomized study. SETTING: Infertility Center, Department of Obstetrics and Gynecology, University of Milan. PATIENT(S): Patients with male factor and unexplained infertility undergoing controlled ovarian hyperstimulation (COH) and IUI. INTERVENTION(S): After COH with clomiphene citrate and gonadotropins, patients were randomly assigned to one of the following groups: group A received a single IUI 34 hours after hCG administration, group B received a double IUI 12 hours and 34 hours after hCG administration, and group C received a double IUI 34 hours and 60 hours after hCG administration. MAIN OUTCOME MEASURE(S): Number of follicles > 15 mm in diameter on the day of hCG administration, number of motile spermatozoa inseminated, clinical pregnancy rate. RESULT(S): Two hundred seventy-three patients underwent 449 treatment cycles: 90 patients were treated for 156 cycles in group A, 92 patients for 144 cycles in group B, and 91 patients for 149 cycles in group C. The overall pregnancies rates for groups A, B, and C were 13 (14.4% per patient and 8.3% per cycle), 28 (30.4% per patient and 19.4% per cycle), and 10 (10.9% per patient and 6.7% per cycle), respectively. There was a statistically significant difference between group B and groups A and C. CONCLUSION(S): Our data indicate that two IUIs performed 12 hours and 34 hours after hCG administration is the most cost-effective regimen for women undergoing COH cycles with clomiphene citrate and gonadotropins. Although the second insemination adds up to a slightly higher cost, it significantly increases the chance of pregnancy.

Adult↗
PubMed1999

Natural history and pathogenesis of hepatitis C virus related hepatocellular carcinoma.

Generally, 0.4-2.5% of patients with chronic hepatitis C virus (HCV) infection develop hepatocellular carcinoma (HCC). HCC occurs more often in patients with cirrhosis and in those with increased liver cell proliferation. HCV-related tumors occur in older patients and often have a less aggressive course than HCC, related to other etiological factors. Many HCV-related HCC are multifocal in origin. However, many tumors grow as a single hepatic nodule for years before generating satellite or distant tumor nodules. The growth pattern varies from one tumor to another, with tumor volume doubling times ranging from 1 to 20 months. Tumor progression and hepatic failure are the leading causes of death in most patients. Using the polymerase chain reaction technique, HCV-RNA has been almost invariably detected in serum and tumor tissue of anti-HCV patients with HCC. In many patients, HCV-RNA was found to belong to the possibly more pathogenic type 1b. However, it is unlikely that HCV plays a direct role in liver tumorogenesis, since no reverse transcriptase activity has been found in infected livers. One current opinion is that HCV may promote cancer through cirrhosis, which is per se an important risk factor for this tumor. In HCV carriers, the risk of developing HCC and having more severe tumor disease may be increased by coexisting hepatitis B virus (HBV) or alcohol abuse, further supporting the idea that both HCC and cirrhosis might be a result of the interplay of several risk factors. HCC could also be the consequence of HCV interacting with cellular genes that regulate cell growth and differentiation, independent of the effect of cirrhosis.

Carcinoma, Hepatocellular↗