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Biomedical subjects

C Colombo

Publications and source records attributed to C Colombo.

At least 127 records · Page 7Linked to original sources
PubMed1988

Neurofunctional assessment of early phases of Alzheimer's disease: a preliminary note on hemispheric EEG characteristics during cognitive tasks.

EEG characteristics, in terms of power distribution in 1-4, 4-6, 6-8, 8-10, 10-13, 13-18, 18-30 Hz frequency bands were evaluated in six putative non-medicated male Alzheimer patients. The latter were compared with six age and sex-matched normal controls during both resting conditions and tactile identification tasks specific for the left and right hemispheres. The result indicate a significant difference in the power of the 8-10 frequency band between the two groups and a significant hypovariability in the 6-8 and 8-10 bands during tactile tasks: Alzheimer patients showed reduced power and, also, where less reactive, no differences between the left and right hemispheres having appeared. These findings seem to confirm the specificity of EEG modifications in Alzheimer's disease, even in the very early phases of the pathological process. Possible implications are discussed in the light of some biochemical hypotheses.

Alzheimer Disease↗
PubMed1987

Biliary bile acid composition of the human fetus in early gestation.

Using analytical techniques, which included capillary column gas-liquid chromatography and mass spectrometry, detailed bile acid profiles were obtained for 24 fetal bile samples collected after legal abortions were performed between the 14th and 20th wk of gestation. Qualitatively, the bile acid profiles of all fetal bile samples were similar. The predominant bile acids identified were chenodeoxycholic and cholic acid. The presence of small but variable amounts of deoxycholic acid and traces of lithocholic acid suggested placental transfer of these bile acids from the maternal circulation. 3 beta-Hydroxy-5-cholenoic acid was detected at higher levels than lithocholic acid. A conspicuous feature of the profiles was the presence of bile acids with hydroxyl groups at positions C-1 and C-6, and one other nuclear position of unknown origin, indicating fetal hepatic synthesis via pathways different from those normally seen in the adult. Quantitatively total biliary bile acid concentrations were extremely low (less than 0.05 mM) before wk 17 of gestation, but thereafter concentrations markedly increased reflecting a possible surge in bile acid synthesis; however, the ratio of cholic:chenodeoxycholic acids remained relatively constant over this period (mean +/- SD = 0.85 +/- 0.36) and different from that reported for the healthy newborn (ca. 2.5) and adult (ca. 1.6). These data indicate an immaturity in hepatic 12 alpha-hydroxylation of bile acids during early development and may explain why other pathways, in particular 1 beta and 6 alpha-hydroxylation, are activated at this stage of life.

Bile Acids and Salts↗
PubMed1987

[Spontaneous hematoma syndrome of the abdominal rectus muscles (Differential diagnosis of acute abdomen and other diseases. Personal cases].

The authors examine the problem of the differential diagnosis of spontaneous hematoma of the abdominal rectus muscles versus "surgical" or "non-surgical" acute abdomen and other conditions. The clinical characteristics and investigative methods used are reviewed with a view to avoiding diagnostic errors. In addition, the authors discuss 6 clinical cases which they have observed personally.

Abdomen, Acute↗
PubMed1986

Ethanol administration in the rat decreases prostacyclin production by isolated brain microvessels.

The effects of short- and long-term ethanol administration to rats on basal levels and formation of prostacyclin (PGI2) measured as 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and on lipid class content and fatty acid composition of isolated brain microvessels (BMV) were studied. After acute treatment (2 h, at the peak of plasma ethanol concentration) basal 6-keto-PGF1 alpha levels in BMV and release on incubation were reduced to 50% of control values. After chronic administration (15 days), PGI2 release was reduced to about 40% of control values, without changes in basal levels. Total lipid, phospholipid, and cholesterol levels in BMV, measured after prolonged administration of alcohol, were not modified. Also, only minor changes in the fatty acid composition of individual phospholipid classes were detected. The observed reduction of PGI2 synthesis in BMV thus could not be related to changes of the fatty acid precursor pool in the preparation. Precursor release and/or the biosynthetic pathways may be affected by ethanol administration.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Presence of fibronectin in articular cartilage in two animal models of osteoarthritis.

Fibronectin content was determined in articular cartilage in a spontaneous dog model and in a meniscectomy rabbit model of osteoarthritis. Determination of the fibronectin content of urea extracts of articular cartilage by an enzyme linked immunosorbent assay (ELISA) disclosed that degenerated cartilage contained from 10- to 40-fold more fibronectin than normal cartilage. The finding that cartilage fibronectin content was increased in both animal models suggests that elevated cartilage fibronectin content is a general feature of the osteoarthritic process. Immunoperoxidase studies disclosed that fibronectin was distributed throughout the matrix in hyaluronidase treated normal and osteoarthritic cartilage from both animal models, but quantitative differences in fibronectin were not observed by these techniques.

Animals↗
PubMed1985

Serum bile acid composition in patients with cystic fibrosis.

Serum bile acid composition was examined in detail using capillary column gas chromatography and mass spectrometry in 10 children with cystic fibrosis (CF) and 4 healthy children. The mean total bile acid concentration in fasting serum of CF patients was 2.33 +/- 0.84 mumol/l, slightly lower than but not statistically significantly different from healthy controls (mean 2.86 +/- 0.98 mumol/l) and appeared to show no relationship to the degree of exocrine pancreatic insufficiency. Analysis of individual serum bile acids in these children showed that cholic acid represented less than 10% of the total bile acids. Chenodeoxycholic acid was the predominant serum bile acid; the mean concentration in CF patients was 0.98 +/- 0.51 mumol/l, lower than for the healthy controls (1.69 +/- 0.84 mumol/l). Concentrations of lithocholic acid, 3 beta-hydroxy-5-cholenoic, ursodeoxycholic and 3 beta, 7 alpha, 12 alpha-trihydroxy-5 beta-cholanoic acids in fasting serum samples of the CF patients were not significantly different from the healthy control sera but were higher than those normally found in adults. Measurements of fecal bile acid excretion indicated an increased loss of primary bile acids in patients with CF consistent with an impairment of the enterohepatic circulation of bile acids.

Adolescent↗
PubMed1985

Effects of acute and chronic ethanol administration on thromboxane and prostacyclin levels and release in rat brain cortex.

The effects of acute (3 g/kg i.p. two hours before sacrifice) and chronic (6% in drinking water and libitum for 15 days) ethanol administration to male rats (200 g body weight) on basal levels and release of TxB2 and 6-keto-PGF1 alpha in brain cortex were studied. Also the effects of chronic ethanol (30 days) on the fatty acid composition of brain cortical tissue and liver phospholipids were investigated. Acute treatment reduced basal levels of 6-keto- PGF1 alpha in brain cortical tissue (rats sacrificed by microwave radiation) and decreased the accumulation of 6-keto-PGF1 alpha in brain cortex after post-decapitation ischemia (PDI). Basal TxB2 levels were also reduced in brain cortex, but TxB2 release during PDI was enhanced. Chronic treatment (15 days) induced changes of TxB2 and 6-keto-PGF1 alpha levels and release during PDI in brain cortex less pronounced than those observed after acute treatment. The reduced effectiveness of chronic ethanol on brain vasoactive eicosanoids suggest adaptation processes. After chronic treatment (30 days), the fatty acid composition of brain cortex total phospholipids were not significantly modified. Changes of eicosanoid production after ethanol were thus independent from modifications of the fatty acid precursor pool(s). Ethanol-induced changes in the production of vascular eicosanoids in the CNS may be of relevance to the action of the compound on the CNS and may also have implications for the clinic.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Correlation between fetal and maternal serum bile acid concentrations.

Serum concentrations of different bile acids (BA) were determined by radioimmunoassay in 56 human fetuses and mothers. Serum was obtained immediately after legal abortion, performed between the 14th and the 21st wk of gestation. Conjugated cholic (CCA) and chenodeoxycholic acid (CCDCA) concentrations were determined in 33 cases, conjugated lithocholic (CLCA) and deoxycholic acid (CDCA) in 20, and sulfolithocholyglycine (SLCG) in 15. In fetal blood, mean concentrations of CCA (0.80 +/- 0.40 mumol/liter), CCDCA (4.50 +/- 2.70 mumol/liter), and CLCA (1.70 +/- 1.04 mumol/liter) were significantly higher than those in the mother (CCA 0.34 +/- 0.17 mumol/liter; CCDCA 0.79 +/- 0.34 mumol/liter; CLCA: 0.70 +/- 0.30 mumol/liter; p less than 0.001); fetal serum levels of CDCA (0.46 +/- 0.32 mumol/liter) and SLCG (0.15 +/- 0.09 mumol/liter) were lower than in the mothers (CDCA 1.20 +/- 0.80 mumol/liter, p less than 0.001; SLCG 0.40 +/- 0.30 mumol/liter, p less than 0.01). There was no correlation between levels of BA and gestational age. Serum total protein and albumin concentrations were both reduced in 10 fetuses as compared with the mothers. These data support the concept of a state of physiologic cholestasis during development and suggest that placental transfer of primary BA occurs mostly in the fetal to maternal direction. This transfer could be facilitated by the reduced fetal plasma albumin concentration, since BA in free solution diffuse more easily through the placenta. There is evidence of lithocholic acid synthesis in the fetal liver, while deoxycholic acid appears to be mostly of maternal origin. Finally, sulfation of BA is poorly developed at this age of gestation.

Bile Acids and Salts↗
PubMed1984

Sex differences in platelet thromboxane and arterial prostacyclin production in control and n-6 fatty acid supplemented rats.

Sex differences in eicosanoid production in platelets and vessel walls have been studied in control and n-6 fatty acid supplemented rats. In platelet rich plasma (PRP) of control female rats, arachidonic acid (AA) levels in phospholipids (PL), thromboxane B2 (TxB2) formation following collagen stimulation and aggregatory responses to collagen were higher than in PRP of male rats. 6 keto PGF1 alpha release from PRP-perfused isolated aortas were the same for both sexes, but the antiaggregatory activity of the wall was higher in males than in females, in association with a greater sensitivity of male platelets to prostacyclin. The administration of n-6 fatty acid supplements increased AA level in PL, TxB2 production and aggregation only in male platelets. Production of 6 keto PGF1 alpha and the antiaggregatory activity of aortic walls were reduced after dietary treatment in males, but biochemical and functional parameters were not correlated in females. The results indicate complex sex-related differences in fatty acid metabolism and eicosanoid production, and in responses to n-6 dietary fatty acids in platelets and the vascular system in the rat.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Reliability of ultrasound for the diagnosis of hypertrophic pyloric stenosis.

An ultrasound (US) examination might be the best way to study the pylorus and its pathological states once the reliability of this technique has been demonstrated. In order to evaluate the reliability of a sonographic diagnosis of hypertrophic pyloric stenosis (HPS), 17 randomly chosen patients with HPS were examined with both ultrasonography and radiography and then operated on or followed up clinically. Rank correlation between the size and morphological features of the pylorus was found in babies with HPS using US. No false positives or negatives were obtained, and all true positives and negatives were detected. Because of this and the safety of the US technique we wish to emphasize that it should be considered the method of choice in screening infants with severe vomiting. Whenever HPS is suspected from clinical observation, ultrasonography should precede a radiological examination before surgery.

Female↗
PubMed1984

Bile acid malabsorption in cystic fibrosis with and without pancreatic insufficiency.

Serum conjugated cholic acid (CCA) and conjugated chenodeoxycholic acid (CCDCA) fasting levels were measured in 30 children with cystic fibrosis (CF) without liver involvement, and mean levels were not significantly different from control values. In seven children (four with partially corrected pancreatic insufficiency and three without pancreatic insufficiency) serum levels of both primary bile acids (BAs) were also measured after the ingestion of a standard liquid meal; the values were then compared with those for total and fractional fecal BA excretion. The CCA mean peak increase was significantly reduced in patients with pancreatic insufficiency (p less than 0.01), as well as in those without pancreatic insufficiency (p less than 0.05), as compared to controls. The CCDCA mean peak increase was reduced only in patients with pancreatic insufficiency (p less than 0.01). Fecal results confirmed serum data, showing a significantly increased excretion of cholic and deoxycholic acids in patients without pancreatic insufficiency as compared to controls (p less than 0.02), despite a similar total BA excretion. In patients with pancreatic insufficiency, total fecal BA levels were markedly increased compared to control values (p less than 0.001); the fecal percentage of chenodeoxycholic and lithocholic acids was greater than that recorded in patients without pancreatic insufficiency (p less than 0.05), in agreement with the different behaviour of serum CCDCA postprandial curves for the two groups of patients. The results are consistent with selective malabsorption of cholic acid in CF, independent of the presence of pancreatic insufficiency; they confirm the usefulness of serum BA postprandial determinations in measuring BA malabsorption.

Adolescent↗
PubMed1983

A new model of osteoarthritis in rabbits. I. Development of knee joint pathology following lateral meniscectomy and section of the fibular collateral and sesamoid ligaments.

A partial lateral meniscectomy procedure has been developed for the induction of a predictable and reproducible degenerative joint disease in knees of rabbits. The procedure adopted involves section of the fibular collateral and sesamoid ligaments and removal of 4-5 mm of the anterior lateral meniscus. In most experiments the animals are killed and tissues obtained for histologic examination at 6 weeks. Section of the ligaments alone (with or without penetration of the joint space) did not result in significant pathologic change. Significant degeneration was observed in tibial and femoral cartilage when the meniscus as well as the ligaments were cut, but the most extensive lesions were seen when a piece of the anterolateral meniscus was actually removed. These lesions included fibrillation, ulceration and erosion, "clone" and osteophyte formation, loss of chondrocytes, and loss of safraninophilic staining in the articular cartilage. The incidence and distribution of lesions with time following surgery were also investigated. Lesions were observed as early as 1-2 weeks post-surgery and increased in number and severity up to 12 weeks. A global scoring system has been devised to permit statistical comparisons of lesion incidence and severity in different groups of rabbits. This scoring system has enabled us to test drug efficacy in the rabbit lateral meniscectomy model of osteoarthritis.

Acid Phosphatase↗
PubMed1983

A new model of osteoarthritis in rabbits. II. Evaluation of anti-osteoarthritic effects of selected antirheumatic drugs administered systemically.

A battery of drugs with antirheumatic properties was tested for effects on the progress of osteoarthritis induced by a lateral meniscectomy procedure in knee joint cartilage of rabbits. Oral administration of the potent glucocorticoids, paramethasone acetate or triamcinolone, resulted in dramatic inhibition of cartilage degeneration. Significant protection against development of osteoarthritic lesions was also observed in rabbits treated with pirprofen or CGS 5391B but not with 9 other nonsteroidal antiinflammatory drugs. A marked reduction in joint pathology was also observed in rabbits treated with tribenoside (a glucofuranoside derivative) and with tamoxifen (an anti-estrogen). Slightly protective effects of borderline significance were observed with orgotein (a superoxide dismutase), gold sodium thiomalate, and D-penicillamine. Chloroquine and calcitonin were without effect. Therapeutic effectiveness of drugs in this model of osteoarthritis cannot be explained on the basis of their antiinflammatory properties.

Animals↗
PubMed1983

A new model of osteoarthritis in rabbits. III. Evaluation of anti-osteoarthritic effects of selected drugs administered intraarticularly.

A battery of steroidal and nonsteroidal antirheumatic drugs and protease inhibitors were tested by intraarticular injection for effects on osteoarthritis of the knees of rabbits subjected to partial lateral meniscectomy and section of the sesamoid and collateral fibular ligaments. Among the standard drugs, only the glucocorticoid, triamcinolone hexacetonide, and the protease inhibitor, tranexamic acid, exhibited significant anti-osteoarthritic activity. An experimental drug, GPA 2163, also offered some protection against joint degeneration. The nonsteroidal antiinflammatory drugs had no effect on the development of osteoarthritis in the model.

Animal Diseases↗
PubMed1983

Evaluation of an oral ursodeoxycholic acid load in the assessment of bile acid malabsorption in cystic fibrosis.

Serum levels of ursodeoxycholic acid (UDCA) were measured by radioimmunoassay in 20 children with cystic fibrosis (CF) and in eight controls, who had received 300 mg of this bile acid orally. Area under the curve (AUC) after UDCA load was significantly reduced (25.24 +/- 9.54) in CF patients, as compared to controls (52.98 +/- 5.87 mean values +/- SD percent dose/liter X hr X kg body weight, P less than 0.001). AUC values were compared with daily fecal bile acids (BA) and fat excretion, and with serum fasting conjugated cholic (CCA) and chenodeoxycholic (CCDCA) acid levels. Total fecal BA were increased in CF patients (7.84 +/- 5.57 mg/kg/day) as compared to control values (2.7 +/- 1.1 mean +/- SD, P less than 00.5); they were inversely correlated with AUC values (r = 0.48) but not with steatorrhea (r = 0.32). UDCA load seems to be useful in detecting BA malabsorption in CF. Fasting CCA levels did not significantly differ in CF patients (0.87 +/- 0.61 mumol/liter) and in controls (0.60 +/- 0.26 mumol/liter) and did not correlate with fecal BA excretion. Fasting CCDCA mean levels were significantly increased (mainly in CF patients with liver damage), suggesting a lowered first-pass extraction in the liver: their determination may be useful in the follow-up of liver involvement in CF.

Adolescent↗
PubMed1983

Fish oil administration as a supplement to a corn oil containing diet affects arterial prostacyclin production more than platelet thromboxane formation in the rat.

The administration to male rats of 5 en % fish oil (FO) as supplement to a diet containing 5 en % corn oil (CO), selectively and markedly decreased arterial parameters (6-keto-PGF1 alpha formation and platelet antiaggregatory activity) assessed in isolated aortic segments perfused with autologous platelet rich plasma (PRP). Platelet parameters (ADP-induced aggregation, TxB2 formation in thrombin-stimulated PRP and sensitivity to exogenous PGI2) were instead minimally affected. Eicosapentaenoic acid (EPA, 20:5 n-3) did not accumulate in plasma, platelet and aorta lipids and arachidonic acid (AA, 20:4 n-6) levels declined markedly only in the plasma compartment. When FO was given alone at the same 5 en % level, both arterial and platelet parameters were similarly affected. EPA accumulated in plasma cholesterol esters and was present in appreciable concentrations also in platelets and aortic walls. AA levels declined markedly in plasma lipids and appreciably also in platelet and aorta lipids. It is concluded that a) arterial and platelet parameters are differentially affected by FO administration depending upon the presence of n-6 polyunsaturated fatty acids in the diet, b) 6-keto-PGF1 alpha production by arterial tissue does not seem to be related to changes of PG precursor fatty acid levels in the phospholipid fraction.

Animals↗