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Biomedical subjects

M Colombo

Publications and source records attributed to M Colombo.

At least 109 records · Page 6Linked to original sources
PubMed1996

Memory procedures, performance and processes in pigeons.

Short-term memory in pigeons is studied in the delayed matching-to-sample procedure where information is forgotten over short periods of time. Performance in this task reflects the separate influences of attention to the sample stimuli and memorial processes and is determined by a range of procedural variables. Forgetting functions can be obtained by varying the duration of the retention interval and can be quantified in terms of the parameters of a fitted function, such as the negative exponential. These parameters provide measures of initial discriminability and rate of forgetting and are sensitive to the effects of drugs known to influence the cholinergic, GABA and dopaminergic systems. The results of behavioral pharmacological studies suggest that the effects of a variety of drugs on initial discriminability and rate of forgetting are quite similar for pigeons and monkeys. We conclude that pigeons serve as an effective model to examine the effects of agonist and antagonist drugs on memory.

Animals↗
PubMed1996

A randomized comparison of Burch colposuspension and abdominal paravaginal defect repair for female stress urinary incontinence.

OBJECTIVE: Our aim was to compare Burch colposuspension and paravaginal repair for success rates, complications, and urodynamic effects when the procedures are used in the treatment of stress urinary incontinence. STUDY DESIGN: Thirty-six patients were enrolled. A full urodynamic evaluation was repeated 6 months postoperatively. RESULTS: Twelve (67%) and 17 (94%) subjects (Burch colposuspension vs paravaginal repair) voided spontaneously before discharge (p = 0.04). One patient receiving the Burch procedure underwent urethral dilation for urinary retention. Follow-up was for 1 to 3 years. Differences in subjective and objective cure rates favored the Burch colposuspension over the paravaginal repair: 100% versus 72% (p = 0.02) and 100% versus 61% (p = 0.004), respectively. The paravaginal repair did not produce significant modifications in profilometry. Postoperatively, cotton swab tests had negative results in all patients with the Burch operation and in 33% of those with the paravaginal repair (p = 0.01). CONCLUSION: Paravaginal repair is not recommended for the treatment of stress incontinence, although it was accompanied by a more immediate resumption of voiding.

Adult↗
PubMed1996

Epidemiological, clinical and therapeutic associations of hepatitis C types in western European patients.

BACKGROUND/AIMS: Different variants of hepatitis C virus might show different susceptibility to interferon alpha treatment, but it is important to understand whether this difference in sensitivity reflects an association with other factors, such as cirrhosis or age. METHODS: We have used an enzyme-linked immunosorbent hepatitis C virus typing assay based upon the detection of antibody in patient's era to type-specific NS-4 antigens to investigate the effect of hepatitis C virus type in 610 patients with chronic hepatitis C virus infection. The influence of viral types and their interdependency with host factors were separately analyzed to establish which factors executed an independent effect on the probability of sustained response. RESULTS: There was a marked difference in the distribution of hepatitis C virus types with age: infection with type 3 was more common in younger patients. The distribution of hepatitis C virus type with age is accounted for by differences in risk-factors for infection in different age groups. The frequency of cirrhosis increased markedly with age. Even after standardization for age, center and the presence of cirrhosis, viral type was strongly related to the outcome of infection. CONCLUSIONS: Our data suggest that enzyme-linked immunosorbent hepatitis C virus typing could assist in patient selection for interferon treatment to improve sustained response rates. Together with measurement of viral load, hepatitis C virus typing may serve to indicate the probability of response in patients with chronic hepatitis C, and to elucidate antiviral mechanisms in the disease. The serotyping assay provides a relatively inexpensive screening method to determine the infecting hepatitis C virus type, which could facilitate therapeutic decisions and strategies in patients with chronic hepatitis C.

Adolescent↗
PubMed1996

Increased detection of antibody to hepatitis C virus in renal transplant patients by third-generation assays.

To assess the sensitivity and specificity of third-generation assays for antibody to hepatitis C virus (anti-HCV), sera from 244 renal transplant patients (113 positive for anti-HCV enzyme-linked immunosorbent assay [ELISA]-2) were studied. Hepatitis C virus RNA was detected by a reverse-transcripted nested polymerase chain reaction. Antibody to HCV was detected by ELISA-3 in 108 (96%) ELISA-2-positive samples. Five (4%) ELISA-2-positive sera were negative by both ELISA-3 and polymerase chain reaction. In the anti-HCV-negative group, six (5%) additional cases were ELISA-3-positive; three of these were confirmed by recombinant immunoblot assay-3 (RIBA-3) and polymerase chain reaction. Recombinant immunoblot assay-3 was used to resolve 82 RIBA-2-indeterminate and three RIBA-2-negative sera. Using RIBA-3, 49 (60%) RIBA-2-indeterminate samples were positive, five (6%) ELISA-3-negative samples were negative, and 28 (34%) were remained indeterminate. Recombinant immunoblot assay-2-negative samples were indeterminate with RIBA-3. Hepatitis C virus RNA was detected in all RIBA-3-positive and 58% of the RIBA-3-indeterminate samples. Third-generation assays for anti-HCV are more sensitive and specific than second-generation assays in renal transplant patients.

Adolescent↗
PubMed1996

The natural history of hepatitis C.

The natural history of hepatitis C is complex and still poorly known. Hepatitis C virus (HCV) replication can be detected very soon after exposure and, at least in the transfusional setting, it persists indefinitely in up to 90% of the cases. While liver damage during the acute phase of hepatitis is almost invariably mild (fulminant cases are exceptions), chronic sequelae of HCV infection may be severe in the long run. Chronic hepatitis C, in fact, is a long-lasting indolent process which leads to cirrhosis in approximately 20% of all infected patients. Hepatocellular carcinoma is a well-recognized complication of old infections, as are a number of extrahepatic manifestations, including type II cryoglobulinaemia. The determinants of the severity of the liver disease are still unclear. However, the risk of cirrhosis seems to be greater for patients with old infections, those infected with the genotype 1b and those with associated conditions. The latter are a heterogeneous and increasing group of 'problem' patients, including patients who are co-infected with the human immunodeficiency virus (HIV1), or who are being treated with cytotoxic or immunomodulating drugs. Data suggest that the natural history of hepatitis C is altered in patients with associated conditions, and this might have an impact on strategies of patient management and treatment.

Carcinoma, Hepatocellular↗
PubMed1996

Relevance of lymphoproliferative disorders and of anti-C1 inhibitor autoantibodies in acquired angio-oedema.

We looked for autoantibodies to C1 inhibitor (C1-INH) and evaluated the relationship of their presence to the associated lymphoproliferative diseases and to the cleaved form of C1-INH in 13 patients with acquired C1-INH deficiency (acquired angio-oedema (AAE)). At the time of manifestation of angio-oedema symptoms or within a few years the following diseases were diagnosed: liver angioma (n = 1), M-components (n = 7, one of whom also had echinococcal liver cysts), breast cancer (n = 1), chronic lymphocytic leukaemia (CLL; n = 1); three patients had no associated disease. Anti-C1-INH autoantibodies, measured both as immunoglobulin binding to C1-INH immobilized onto microtitre plates (ELISA) and as plasma inhibitory activity of C1-INH function, were found in 12 patients. Binding of C1-INH to paraproteins, transferred to Immobilon after agarose gel electrophoresis, was detectable in five of seven M-components associated with AAE. Immunoblotting analysis of SDS-PAGE-separated plasma demonstrated that C1-INH circulated in the cleaved 96-kD form in the 12 patients with autoantibodies, but not in the one without. In conclusion, the large majority of our patients have autoantibodies to C1-INH. Circulating autoantibodies are necessary for the generation of cleaved C1-INH. The paraproteins associated with AAE are frequently autoantibodies to C1-INH and thus account for its consumption.

Adult↗
PubMed1996

Detection of abnormal intrauterine vascularization by color Doppler imaging: a possible additional aid for the follow up of patients with gestational trophoblastic tumors.

Uterine morphology assessed by transvaginal ultrasound and the hemodynamics of intratumoral vessels assessed by color Doppler ultrasound were prospectively correlated with the clinical outcome of 25 patients with trophoblastic tumors. Twenty patients were followed without treatment (observation group) and 16 achieved complete local resolution. The four subjects with local persistence were combined with five patients referred from other institutions and received chemotherapy (treatment group). In the observation group both techniques had 100% accuracy in predicting local resolution or local persistence. Persistence was predicted 1-3 weeks before the increase of beta-human chorionic gonadotropin (beta-hCG) levels, whereas resolution was observed up to 8 weeks before the disappearance of beta-hCG. In one patient normal uterine morphology and vascularization in the presence of elevated hCG levels was associated with extrauterine spread. In the treatment group, normal uterine ultrasound morphology and negative color Doppler results had 100% negative predictive value. False-positive results were observed in two cases. We conclude that ultrasound evidence of abnormal uterine morphology or persistent vascularization on color Doppler examination with persistent hCG levels is indicative of local persistence. Normal uterine morphology with negative color Doppler results may be associated with extrauterine spread.

Blood Flow Velocity↗
PubMed1996

Influence of different hepatitis C virus genotypes on the course of asymptomatic hepatitis C virus infection.

BACKGROUND & AIMS: The association of liver disease with hepatitis C virus (HCV) genotypes mainly refers to patients with serious liver damage; little information is available on symptomless carriers. The aim of this study was to investigate the correlation of genotypes with clinical course, risk factors for infection, and antibody to HCV reactivity in asymptomatic subjects. METHODS: One hundred nine viremic blood donors with at least 1 year of follow-up were studied; 41 underwent liver biopsy. Genotypes were determined by line-probe assay. RESULTS: Genotype 1 was found in 47 (43.1%), genotype 2 in 48 (44%), genotype 3 in 8 (7.3%), genotype 4 in 2 (1.8%), and coinfections in 4 (3.7%). The relative risk (RR) for a raised pattern of alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltranspeptidase was 2.1 (confidence interval [CI], 1.4-3.2), 1.7 (CI, 1.2-2.4), and 2.8 (CI, 1.6-4.9) in subjects with genotype 1 vs. 0.4 (CI, 0.2-0.7), 0.4 (CI, 0.3-0.7), and 0.4 (CI, 0.2-0.8) in subjects with genotype 2. Chronic hepatitis was found in 68%; the RR of chronic hepatitis was similar for genotypes 1 and 2 (RR, 1.1 [CI, 0.8-1.7] vs. RR, 1.0 [CI, 0.7-1.6]). Reactivity to NS4-derived antigens was infrequent in type 2-infected subjects. CONCLUSIONS: Genotype 2 was as frequent as genotype 1 but associated with less liver function impairment. The high prevalence of chronic hepatitis should be considered in counseling viremic asymptomatic donors.

Adult↗
PubMed1996

Lack of association between type of hepatitis C virus, serum load and severity of liver disease.

Chronic infection with the hepatitis C virus (HCV) may lead to a variety of hepatic lesions from benign inflammation to liver cancer, but the relationships between infection and development of liver disease are poorly understood. To assess whether virus type and load are of pathogenetic importance, 197 Italian carriers with various hepatic lesions were investigated consecutively. Of these, 187 (95%) patients had serum HCV RNA, by reverse transcription-polymerase chain reaction (RT-PCR) with a median level of 1003 x 10(3) genomic equivalents ml-1 according to the branched-DNA assay (b-DNA). One hundred and seven patients (54%) had serotype 1, 22 (11%) had serotype 2, 9 (5%) had serotype 3, 17 (9%) had mixed serotypes and 42 (21%) had no specified serotype. One hundred and thirty four patients were also tested for genotype. The genotype distribution was as follows: 17 (13%) had genotype 1a; 67 (50%) 1b; 29 (22%) 2a; 12 (9%) 3a; 3 (2%) had genotype 1 not classified (NC); 3 (2%) had genotype 2 NC; 2 (1.4%) had genotype 4 and 1 (1%) had mixed genotype 1a + 3a. No virus type was associated with any particular histological diagnosis and all were equally distributed between progressive and non-progressive liver disease groups. Serum HCV-RNA levels were similar in the liver diseased groups. By analogy to hepatitis B, there was no direct correlation between type and level of viraemia and the severity of the underlying liver damage.

Adult↗
PubMed1996

The Burch colposuspension for women with and without detrusor overactivity.

OBJECTIVE: To compare the results of the Burch colposuspension in women with stress urinary incontinence and detrusor overactivity with those obtained in women with stress incontinence and stable bladders. Additionally, to analyse the value of two detrusor instability indexes and of standard cystometric parameters in predicting the surgical outcome. DESIGN: Retrospective cohort study. SETTING: Secondary referral centre Urodynamics Unit, San Gerardo Hospital, Monza. SAMPLE: Forty-four women with detrusor overactivity (21 with low compliance bladder and 23 with detrusor instability) and 44 with stable bladders. They were matched for age, parity, dystocia, menopause, body mass index, previous vaginal surgery, heavy work, urethral functional length and maximum urethral closure pressure. RESULTS: At two years follow up, the cure rate of stress incontinence was 95% in the control group (patients with stable bladders) and 75% in detrusor overactivity group (odds ratio 0.1, 95% confidence interval 0.01-0.9, P = 0.02). No significant differences were observed between cured and failed patients according to both detrusor instability indexes. Likewise, mean pre-operative standard cystometric values of cured and failed patients showed no differences. CONCLUSIONS: Although results were better in women with stable bladders, we believe that the success of the Burch colposuspension in cases with mixed incontinence should be considered satisfactory. No pre-operative cystometric parameter consistently predicting the surgical outcome on stress incontinence was identified.

Cohort Studies↗
PubMed1996

Treatment of "problematic" hepatitis C patients.

There is limited information about the natural history of hepatitis C in problematic patients and this may affect development of treatment strategies. In patients with persistently normal serum transaminases, infection is often a benign condition which does not require therapy. By contrast, treatment with antiviral drugs is advisable for recipients of renal or liver grafts who may have shortened life expectancies as a consequence of hepatitis C. However, interferon alpha, which is the only available anti-hepatitis C treatment, has limited efficacy in immuno-compromised patients and it may accelerate graft rejection in some. Patients coinfected with the human immuno-deficiency virus (HIV-1) are another group for which treatment is uncertain, mainly because of the short survival times due to HIV-1. Thus, the current policy is not to treat HIV-1/HCV coinfected patients. Symptomatic patients with serum cryoglobulins may respond to interferon therapy, but symptoms recur in virtually all these patients after withdrawal of treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1996

[Challenge for cow's milk protein intolerance diagnosis. Comparison between different modalities].

BACKGROUND: The diagnosis of cow's milk protein intolerance (CMPI) is mainly based on the response to the elimination diet and to the subsequent exposure to these proteins (challenge). METHODS: To find out whether a "formal", strictly scheduled challenge was better than a less formal test in establishing CMPI diagnosis, records were reviewed of 87 children studied in 5 Hospitals in the Milan area during the last 3 years. RESULTS: The study showed that the diagnostic approach (formal vs informal challenge) did not affect the probability of confirming CMPI diagnosis (21% vs 19%). Moreover, this probability was not affected by the source of the first diagnosis (Hospital vs Family Doctor), the time elapsed between first diagnosis and challenge, and the laboratory tests performed during the challenge. CONCLUSIONS: Therefore, a less strictly scheduled approach could be conveniently suggested to confirm CMPI diagnosis, at least in unselected cases.

Animals↗
PubMed1996

[Transvaginal echography in the study of urinary stress incontinence].

Hypermobility of the bladder neck in response to increased intraabdominal pressure is one cause of stress urinary incontinence in women. Vaginal ultrasound (u.s.) is reliable and minimally invasive method for demonstrating bladder neck hypermobility. The Authors studied 50 women with S.U.I. and 40 with no history of S.U.I. measuring the distance from the bladder neck to the midline of the symphysis pubis (P.V.) and the angle between the BP line and the midline of the symphysis pubis (A.I.U.). The continent women were characterized by a median A.I.U. of 70 degrees and mean B.P. of 25.6 mm, at rest, a median A.I.U. of 80 degrees and a mean B.P. of 20 mm. at stress. The incontinent women were characterized by a median A.I.U. of 80 degrees and mean P.V. of 22.5 mm. at rest, and a median A.I.U. of 95 degrees and mean P.V. of 10 mm. at stress. There is a significant difference between the two groups. The Authors recommend the vaginal u.s. as reliable, practical, economical and patient accepted method to study the bladder neck mobility.

Female↗
PubMed1996

Obesity and the sympathetic nervous system.

Several epidemiological studies have shown that obesity represents an independent risk factor for development of cardiovascular diseases, including hypertension, myocardial ischaemia, and cardiac arrhythmias. Although the metabolic and the haemodynamic alterations occurring in the obese state have been well defined for several years, our knowledge on the sympathetic alterations occurring in this condition is more scarce and controversial. This paper reviews the evidence that human obesity is characterized by abnormalities in sympathetic cardiovascular control, in the light of the results of recent studies performed by employing a sensitive technique to assess sympathetic activity in humans, i.e. microneurography. Evidence is provided that sympathetic overactivity is a common hallmark of the obese state, even when blood pressure levels are within the normal range. It will also discuss the potential mechanisms responsible for this sympathetic activation, suggesting that overweight-related metabolic alterations, such as the insulin resistance state, and abnormalities in sympathetic cardiovascular control exerted by arterial baroreceptors may play a pathogenetic role. Finally, the effects of body weight reduction on the sympathetic overactivity which characterizes the obese state will also be examined.

Energy Intake↗
PubMed1996

[Cognitive functions of school children with normal IQ and histories of severe and early malnutrition].

This is a cross section study designed to evaluate the long lasting consequences of early and severe undernutrition on the development of basic cognitive functions. Attention, memory and problem-solving capacity were assessed in a group of 16 school children, who were severely undernourished during the first two years of age. They were compared with a group of 16 children with a normal growth. All subjects, age 8 to 10, had a normal intellectual coefficient and they belonged to the me same socioeconomical level. Memory was measured with a modified version of subtest of digits from WISC; attention was evaluated with a modified version of the Continuous Performance Task and problem-solving was measured with the Anstey Domino Test. A personal computer was used to assess the cognitive functions. The children who were undernourished during infancy presented lower scores in memory (number of the digits) and in problems solving (number of correct answers). They also had a worse performance than the control group in the same response time, when attention was evaluated. These results suggest that early severe undernutrition had deletereous effects on basic cognitive functions.

Attention↗
PubMed1995

Effects of a novel 5-HT1A receptor agonist, E4424, on gastric adherent mucus levels following restraint stress in rats.

Several novel arylpiperazine serotonin 1A receptor agonists, developed as anxiolytics, have antisecretory and gastroprotective effects in rats. E4424 (2-¿4-[4-(4-chloropyrazol-1-yl)butyl]-1-piperazinyl ¿pyrimidine; Lesopitron dihydrochloride), has potent anti-gastric secretory and antiulcer effects. Preliminary data indicated an enhancing effect of E4424 on gastric mucus that may underlie its gastroprotective actions. We therefore tested the effects of acute and chronic administration of E4424 and of a reference 5-HT1A receptor agonist, 8-OHDPAT [8-hydroxy-2-(di-n-propylamino)tetralin], on gastric mucus levels in rats subjected to cold-restraint stress, a procedure associated with depletion of gastric mucus and the development of mucosal injury. Acute oral administration of E4424 increased adherent mucus levels by 12%, 11%, and 13%, relative to controls. Chronic E4424 significantly increased gastric mucus relative to controls (69% increase). Acute oral treatment with 8-OHDPAT did not affect gastric mucus level. Acute intraperitoneal 8-OHDPAT slightly increased mucus levels. Chronic twice per day 8-OHDPAT did not affect mucus levels; however, chronic once per day treatment with 8-OHDPAT significantly elevated gastric mucus levels at the highest doses used. For E4424, there is a strong correlation between reduction of gastric mucosal injury and increase in gastric mucus level, suggesting that the action of E4424 on glandular mucus levels is an important mechanism underlying its gastroprotective effects.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

A randomized trial of open versus closed vaginal vault in the prevention of postoperative morbidity after abdominal hysterectomy.

OBJECTIVE: Our purpose was to evaluate the effects of two surgical techniques, closed vaginal vault with two layers of continous 3-0 polyglactin suture versus open vaginal vault with a locking 3-0 polyglactin suture, after abdominal hysterectomy. STUDY DESIGN: A prospective, randomized trial was performed. During the hospital stay and 4 to 8 weeks after the operation patients were observed for evidence of morbidity. RESULTS: Of the 273 evaluable subjects, 141 had the vaginal vault left open whereas 132 were closed. Ten (7.1%) and eight patients (6.1%) had infections at the operative site (pelvis or abdominal wound) (p = 0.92). A urinary tract infection was diagnosed in three (2.1%) and in four subjects (3.0%) (p = 0.46). A pelvic hematoma developed in two patients of each group (p = 0.66). Vault granulations were recorded in 11% and 12% of subjects (p = 0.97). CONCLUSIONS: This study failed to show some benefit in favor of either of the two surgical policies. A careful surgical technique and antibiotic prophylaxis seem to remain the most important factors in the prevention of postoperative morbidity.

Adult↗