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Biomedical subjects

M Colombo

Publications and source records attributed to M Colombo.

At least 163 records · Page 9Linked to original sources
PubMed1993

Direct characterization of caffeoyl esters with antihyaluronidase activity in crude extracts from Echinacea angustifolia roots by fast atom bombardment tandem mass spectrometry.

Fast atom bombardment (FAB-MS) and fast atom bombardment tandem mass spectrometry (FAB-MS/MS) techniques (negative ions) have been successfully applied for identification of the constituents responsible for the antihyaluronidase activity of Echinacea angustifolia roots, whose extracts are widely employed for the adjuvant therapy of chronic inflammatory diseases. Crude extracts from different solvents were tested for antihyaluronidase activity, and those with the greatest inhibitory action (the ethylacetate, butylacetate and chloroform fractions, IC50 0.44, 0.50 e 0.62 mg/ml) were directly analyzed by MS. Full scan mass spectra produced intense molecular anions: collisional activation of these resulted in tandem mass spectra rich in significant product ions. Four main caffeoyl conjugates were detected and identified by tandem mass spectrometry (daughter and parent ion mode): 2,3-O-dicaffeoyltartaric acid (chicoric acid) and 5-O-dicaffeoylquinic acid (cynarine) and 2-O-caffeoyltartaric acid (caffaric acid) in the ethylacetate fraction. Among these caffeoyl conjugates, chicoric and caftaric acids had the greatest antihyaluronidase activity: IC50 = 0.42 and 0.61 mM, while the IC50 of cynarine and chlorogenic acid were 1.85 and 2.25 mM.

Acetates↗
PubMed1993

Breakfast omission and cognitive performance of normal, wasted and stunted schoolchildren.

This study focuses on the effects of breakfast omission on cognitive performance. We studied 279 children from low socioeconomic level background ranging in age from 8 years 7 months to 10 years 11 months, categorized nutritionally as: normal, wasted or stunted. Evaluation comprised three cognitive tasks designed to be applied with a microcomputer. Assessment took place in their natural setting, after a mean of 14 h of overnight fasting, some having received a standard breakfast at random while the remaining children continued a fasting situation. We found no consistent association between study condition and performance in short-term visual memory, problem solving and attention tasks in any of the three nutritional groups. Stunted children showed significantly lower scores in the attention test irrespective of having received breakfast or not. These results suggest that given a motivating short-term task and maintaining routine conditions, missing breakfast does not affect the accuracy of the cognitive performance of children. Nutritionally affected children did not show a particular vulnerability to the fasting condition, but did show a specific cognitive deficit.

Attention↗
PubMed1993

A multicentre randomized clinical trial of recombinant alpha-2a interferon therapy in patients with chronic hepatitis B.

Fifty six previously untreated patients who had been positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) for more than 1 year with detectable serum levels of hepatitis B virus DNA (HBV-DNA) and a liver biopsy performed in the 6 months before enrollment, were randomized to receive recombinant alpha-2a interferon at doses of 3MU intramuscolarly thrice weekly for 6 months or no treatment. Treated and untreated patients had similar clinical characteristics in terms of ALT elevation, HBV-DNA levels, and degree of liver damage. Twenty one had chronic persistent or lobular hepatitis; 28 had chronic active hepatitis and 7 had cirrhosis. The percentages of patients who lost HBeAg at month 6, 12 and 18 were 22%, 32% and 38% in the treated group, and 16%, 20% and 37% in the controls (differences = ns). At the same time intervals, HBV-DNA detected by dot spot hybridization, cleared off in 39%, 39% and 41% of treated patients as compared to 16%, 36% and 37% of controls (difference = p < 0.05 for HBV-DNA clearance at month 6). At the end of follow-up, 12 treated patients (41%, including 8 antiHBe seroconverters) and 10 untreated controls (42%, including 6 anti-HBe seroconverters) had normal aminotransferase levels. Conclusions show that in patients with chronic hepatitis B, clearance of HBV-DNA but not of HBeAg was hastened by a 6-month treatment with low doses of recombinant alpha-2a interferon.

Adolescent↗
PubMed1992

The low risk of hepatitis C virus transmission among sexual partners of hepatitis C-infected hemophilic males: an international, multicenter study.

To study the transmission rate of hepatitis C virus (HCV) in the female sexual partners of antibody-positive hemophilic males, 106 partners from three hemophilia centers located in Europe, America, and Australia were tested for HCV seropositivity using a first-generation enzyme-linked immunosorbent assay (ELISA-1) and, subsequently, a second-generation ELISA (ELISA-2) and a supplemental recombinant immunoblot assay. Additionally, the cohort was tested for the presence of antibody to the human immunodeficiency virus type-1 and hepatitis B virus markers. No female partner was HCV antibody-positive using the ELISA-1 test, whereas five were seropositive by the ELISA-2 test. Three of these five female partners were seropositive on the supplemental test, the remaining two having indeterminate results, for an overall prevalence of 2.7%. Thus, even with the use of sensitive testing, the prevalence of HCV infection remains low in this cohort, showing that the efficiency of heterosexual transmission of HCV is poor.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Hepatitis C virus and hepatocellular carcinoma.

Epidemiological, clinical and laboratory data point to a role of hepatitis C virus infection in hepatocellular carcinoma. The connection appears to be indirect and to be mediated by cirrhosis. Thus, geographical differences can be observed, based on the locally prevalent etiological factors for cirrhosis. In the end, prospective studies of hepatitis C virus infected persons will be needed to elucidate the role of this agent in liver cancer.

Animals↗
PubMed1992

Development of antibody to hepatitis C virus (HCV) in acute and chronic non-A, non-B post-transfusion hepatitis.

The antibody to hepatitis C virus (anti-HCV) was measured by an immunoassay in 507 serum samples from 94 patients with acute and chronic post-transfusion non-A, non-B hepatitis (NANB) and in 436 healthy blood donors. Anti-HCV was found in 70.8 of patients with acute hepatitis, in 78.2 with chronic hepatitis, and in 1.4 of healthy blood donors. In acute hepatitis, anti-HCV appeared in the serum from 4 to 34 weeks after transfusion and from 1 to 30 weeks after the onset of the overt disease. Three patients with resolving hepatitis (21%) and 2 who developed chronic hepatitis (10%) lost anti-HCV during a mean follow-up period of 28 months. Among the 36 patients with chronic hepatitis, 2 (6%) lost anti-HCV after 12 months and 8 years respectively. These data indicate that in recent years HCV has been the major etiologic agent of acute and chronic transfusion-associated hepatitis (TAH) in our geographical area. The late appearance of anti-HCV from the onset of clinical and biochemical signs of acute hepatitis in more than 70% of patients limits the diagnostic utility of this assay for an earlier serological diagnosis of acute NANB hepatitis. Additional studies are required to determine the diagnostic significance of this antibody in chronic NANB hepatitis.

Adult↗
PubMed1992

The epidemiology of hepatitis delta infection in Italy. Promoting Group.

The epidemiology of HDV infection in Italy was assessed in a retrospective study involving 1556 HBsAg chronic carriers on their first presentation at one of the 35 Liver Units in 1987. Total anti-HD was detected in 23.4% of HBsAg carriers and was significantly more frequent in southern than in northern Italy (26.6% vs. 19.1%, p less than 0.01). Age distribution showed that 73% of the anti-HD-positive subjects, but only 56% of the anti-HD-negative subjects, were under 40 years of age (p less than 0.01). Anti-HD prevalence increased with the severity of the liver disease from 3.8% in healthy carriers to 42.5% in cirrhosis. No geographical statistical difference was found among HBsAg healthy carriers or subjects with chronic persistent hepatitis (CPH), while among patients with chronic active hepatitis (CAH) or cirrhosis anti-HD prevalence was much higher in the south (p less than 0.01). The various potential risk factors were evaluated by multiple logistic regression analysis. HDV infection was independently related to young age, residence in the south, i.v. drug abuse, a large family and household contact with an anti-HD-positive carrier. No association was found with blood transfusion or male homosexuality. These findings confirm that HDV infection is endemic in Italy, particularly in some southern areas, where intrafamily contact probably at a young age may favour the spread of the infection.

Adolescent↗
PubMed1992

Monoclonal antibody Ki-67 in the study of the proliferative activity of bladder carcinoma.

We studied the proliferative activity of bladder carcinoma using monoclonal antibody Ki-67, which is able to stain a nuclear antigen exclusively present in cells in the cell cycle, that is with activated deoxyribonucleic acid (DNA). We used this immunohistochemical technique on neoplastic tissue removed by transurethral resection from 101 patients. A significant correlation was observed (p less than 0.003) between cells with activated DNA and histological grading, even though within the context of each grade we observed tumors with a different proliferation index. Furthermore, we studied the location of the activated cells in the context of the tumor. In invasive tumors (stages T1 to T4) cells with activated DNA were always present at the base of implant of the tumor and in the neoplastic tissue that infiltrates the bladder wall. In regard to noninvasive tumors (stage Ta), in 57% of the cases most cells with activated DNA were present in the vegetative portion of the tumor and there were no recurrences at followup, while in 43% of the cases such cells were present also or especially at the base of implant of the tumor, near the lamina propria. In the latter patients we observed a 94% recurrence rate. These results suggest that the immunohistochemical assessment of the proliferative activity of transitional tumors of the bladder, using monoclonal antibody Ki-67, and the evaluation of the location of stained neoplastic cells provide a more reliable estimate of biological aggressiveness than that obtained with histopathological patterns alone.

Antibodies, Monoclonal↗
PubMed1992

Intellectual and physical outcome of children undernourished in early life is influenced by later environmental conditions.

Thirty-five schoolchildren who share a common history of early undernutrition and who were reared after recovery by adoptive families (16), in institutional care (eight) or by their biological families (11) were assessed for physical and intellectual outcome. The adopted children had mean normal weight and height for age, but the children from institutions were significantly shorter. Adopted children had mean Full-scale, Verbal and Performance IQs in the normal ranges, with significant differences from the other two groups, mainly for the Verbal subscale. These results emphasize that the growth and development of early-undernourished children are not irreversibly fixed by the acute illness, but are highly sensitive and modifiable by early and stable environmental improvement.

Adoption↗
PubMed1992

Binding capacities and affinities at mu-, delta- and kappa-opioid sites in membrane suspensions from guinea-pig brain regions.

Binding capacities and affinities (KD) of ligands at mu-, delta- and kappa-opioid binding sites were determined by selective labelling techniques together with analysis of saturation curves in seven regions of the guinea-pig brain. The kappa-sites predominated over the other sites in most regions and were 90% of the total in the cerebellum; binding capacities at kappa-sites were highest in the cortex, intermediate in the cerebellum, striatum and mesencephalon and lowest in the diencephalon, hippocampus and pons-medulla. At the mu-sites, binding capacities were highest in the diencephalon and mesencephalon, with intermediate levels in the pons-medulla, cortex and striatum, and low levels in the hippocampus and cerebellum. The highest binding capacity at the delta-sites was in the striatum, intermediate in the cortex, diencephalon and hippocampus, low in the mesencephalon and pons-medulla and not detectable in the cerebellum. No regional differences in binding affinities were found at mu-, delta- and kappa-sites with [3H]-[D-Ala2,MePhe4,Gly-ol5]enkephalin (KD = 1.10-2,61 nM), [3H]-[D-Ala2,D-Leu5]enkephalin (KD = 0.81-1.94 nM) and [3H]-(-)-bremazocine (KD = 0.083-0.185 nM). Thus in guinea-pig brain there are regional differences in opioid binding capacity and in the distribution of mu-, delta- and kappa-sites, but not in binding affinities.

Animals↗
PubMed1992

The natural history of hepatocellular carcinoma.

Prospective studies of patients with cirrhosis who are at risk for developing hepatocellular carcinoma (HCC), have greatly improved our understanding of the natural history of this tumour. Despite many studies, the controversy of whether HCC originates from one or more than one clone of transformed liver cells is still unsettled. The natural history of HCC in many instances is an extension of that of the underlying cirrhosis, although the course of the tumour disease may vary from patient to patient and in different geographical areas. In Oriental and southern European patients with HCC, a longer time may elapse between diagnosis and death, than in African blacks. The information about tumour development in non-cirrhotic liver is scanty, due to the little known risk factors for this type of tumour which has impeded performing prospective cohort studies of high risk patients.

Asia↗
PubMed1992

[Early diagnosis of phenylketonuria. Follow up of 2 cases].

A screening program for the early diagnosis of phenylketonuria was initiated 24 months ago in the Servicio de Salud Metropolitano Central. Since then, 2 cases with phenylketonuria have been early diagnosed. These patients started their nutritional treatment, consisting of a phenylalanine restricted diet at 14 and 17 days of age. The children are submitted to periodic medical, anthropometric, neurologic, biochemical and psychometric analysis. With a strict control they maintain phenylalanine plasma levels between 2 and 6 mg%. Both patients have a normal psychomotor development at 4.5 and 6.5 months of age and an anthropometric development at p50 of NCHS.

Female↗
PubMed1992

[Duchenne and Becker muscular dystrophy in Chile].

Duchenne muscular dystrophy is one of the best known forms of muscular dystrophy. The incidence in different countries varies from 130 to 390 per million male live births. Becker variety may be considered a mild form of Duchenne dystrophy, with an incidence 10 times lower. A sex linked recessive inheritance is involved in both forms, the affected gene is placed at locus X21. The incidence of both forms in Chile is similar to that reported worldwide, and has been increasing since 1950. Increased CK and LDH levels are confirmed in patients, and overall, they are also higher in female carriers. However only 26% of carriers have increased CK levels and 21% increased LDH levels, compared to normal subjects. Electromyograms show myopathic characteristics in all carrier women. The scope of a prospective clinical, genetic and epidemiologic study currently underway is discussed.

Biomarkers↗
PubMed1991

Hepatocellular carcinoma in Italian patients with cirrhosis.

BACKGROUND AND METHODS: Patients with cirrhosis of the liver are recognized as being at risk for hepatocellular carcinoma. The magnitude of the risk, the natural history of this disease, and the possibilities for detecting potentially curable tumors in patients in the Western world are unknown. To address these questions, we examined 447 Italian patients with well-compensated cirrhosis (which was of viral origin in 62 percent of them) from 1985 through 1990, performing serum alpha-fetoprotein assays and real-time ultrasonography every 3 to 12 months. RESULTS: Hepatocellular carcinoma was found in 30 patients (7 percent) at base line and in another 29 patients (7 percent of 417 patients free of tumor at base line) during follow-up periods averaging 33 months (range, 1 to 48). The cumulative hazard of the development of hepatocellular carcinoma during follow-up was higher among patients with persistently elevated serum alpha-fetoprotein levels (12 with tumors among 42 with such levels) than among those with fluctuating levels (11 among 82) or those with consistently normal levels (6 among 255). Only 17 patients had potentially operable tumors. The proportion of potentially operable tumors among those detected during follow-up was significantly lower than the proportion at enrollment (4 of 29 vs. 13 of 30, P = 0.027). The survival at one year of the 12 patients who underwent surgery was 67 percent, and the tumor-recurrence rate was 60 percent. Outcome was not appreciably different for the five patients who refused surgery. CONCLUSIONS: In the West, as in Asia, patients with cirrhosis of the liver are at substantial risk for hepatocellular carcinoma, with a yearly incidence rate of 3 percent. Our screening program did not appreciably increase the rate of detection of potentially curable tumors.

Adult↗
PubMed1991

Hepatocellular carcinoma in hemophilia.

A questionnaire-based survey involving 11,801 hemophiliacs from 54 hemophilia centers in the USA and Europe documented the occurrence of hepatocellular carcinoma (HCC) in 10 patients. The crude rate of HCC was 3.2/100,000 patients/year, at least 30 times higher than the background incidence of this tumor in the countries of origin of the patients. All patients were Caucasians with hemophilia A, 39 to 74 years of age, and had liver cirrhosis. All had one or more risk factor for cirrhosis and HCC: 5 were positive for serum hepatitis B surface antigen, 4 had the antibody to hepatitis C virus, and 4 had histories of alcohol abuse. Serum alpha-fetoprotein, measured in 6 patients, was significantly elevated in 4 (range: 807-1399 ng/ml), and only moderately elevated in 2 (25 and 171 ng/ml). The onset of HCC was asymptomatic in 5 patients, whereas it was accompanied by jaundice, abdominal pain, or ascites in the remaining patients. Thus, HCC seems to be a more important secondary disease for hemophiliacs than formerly recognized. Since HCC is often asymptomatic, screening hemophiliacs with chronic liver disease with periodic ultrasound scans might increase the changes of detecting HCC at a stage amenable to surgical treatment.

Adult↗