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Biomedical subjects

R Colombo

Publications and source records attributed to R Colombo.

At least 145 records · Page 8Linked to original sources
PubMed1986

Protein phosphorylation in intact cultured sycamore (Acer pseudoplatanus) cells and its response to fusicoccin.

Fusicoccin (FC), a natural diterpene glucoside able to stimulate electrogenic H+ extrusion in higher plants, has been shown to stimulate the phosphorylation of a polypeptide of molecular mass approx. 33 kDa in intact cultured cells of sycamore (Acer pseudoplatanus). The effect is specific, rapid and insensitive to cycloheximide. The presence of the 33 kDa polypeptide and the stimulation by FC have been observed in SDS-containing cell homogenates and in the microsomal and soluble fractions after cell fractionation.

Cycloheximide↗
PubMed1986

Cytoprotection by PGE2, pirenzepine or vagotomy: a transmission and scanning electron microscopic study in rats.

We have studied the effects of PGE2, the anticholinergic pirenzepine and vagotomy on the rat gastric mucosa after challenge with ASA+0.15N HCl or absolute ethanol. The damage was evaluated by quantitative macroscopic examination, light and electron (transmission and scanning examinations) microscopy. We found both macroscopically and microscopically that pirenzepine and PGE2 were effective against ASA+0.15N HCl, but under microscopic examination they were seen to be uneffective 1 hr after absolute ethanol. Vagotomy showed some protection against ASA+0.15N HCl but was totally uneffective against absolute ethanol. The results stress the differences between ASA+0.15N HCl and absolute ethanol damage and show that "cytoprotection" is possible when the mucosa is challenged with noxious agents that do not act by hyperosmolar effects.

Animals↗
PubMed1986

Stereochemical considerations on the inhibition of hepatic epoxide hydrolase by some pesticides and their epoxides.

The present studies identify the steric factors involved in the hydration of epoxide intermediates of some pesticides by hepatic epoxide hydrolase. Investigations were carried out regarding the formation of reactive epoxide intermediates and their different interactions with the hepatic epoxide hydrolase. Some pesticides and their parent epoxides were selected on the basis of the steric hindrance on the oxirane ring. The results indicate that the inhibition of this enzyme depends on the steric hindrance produced by substituents on the oxirane ring of these pesticides. Mono- and di-substituted oxiranes are good substrates of the epoxide hydrolase and non-competitive inhibitors of the hydration of styrene oxide, while tri-substituted epoxides are virtually inactive on inhibiting the hepatic epoxide hydrolase activity.

Animals↗
PubMed1986

Computer-assisted mathematical analysis of sigmoid biological events.

A program in BASIC is described which allows accurate quantification of some numerical parameters that can be objectively correlated to biological indexes in sigmoid biological events. Attention was focused on the polymerization process of actin (a muscle protein with a mol. wt of 42,000 daltons) studied as the variation in the OD360 index with time. The experimental points, if plotted, can be well approximated by a rational function of the type delta OD360 = f(t), which passes through the origin and can be represented graphically by a sigmoid curve. The program was very helpful in comparing the experimental curves and in analysing significant parameters, such as maximum velocity and asymptote, that characterize these curves and whose interpretation would otherwise be purely subjective.

Actins↗
PubMed1986

Aztreonam in the treatment of severe urinary tract infections in pediatric patients.

Aztreonam was administered to 30 patients, ages 0.03 to 15.4 years, with severe and in 21 cases complicated urinary tract infections caused by members of the family Enterobacteriaceae and Pseudomonas aeruginosa which were resistant to ampicillin and susceptible to the study drug in vitro. A mean dose of 47.7 mg/kg was given intramuscularly every 12 h to 26 patients. In four patients with renal insufficiency, the dose was reduced according to pharmacokinetic data. Permanent urine sterilization and clinical cure were achieved in 22 patients, 13 of whom had urological malformations. In two patients with P. aeruginosa and Proteus mirabilis infections, the treatment failed. Another patient had an Escherichia coli reinfection 21 days after the end of therapy. Four patients with various urological abnormalities had gram-positive superinfections, and two patients had gram-negative superinfections during and at the end of therapy: all six had indwelling ureteric splints or pyelostomy as predisposing conditions. No adverse clinical effects were observed. Some transient and slight or moderate alterations were observed at the end of treatment: eosinophilia (nine cases), elevation of hepatic enzymes (eight cases), prolongation of prothrombin time (three cases), and neutropenia (one case). A pharmacokinetic study was performed in six patients with normal renal function and in seven patients with various degrees of renal insufficiency. The elimination half-life of the drug was inversely correlated with the glomerular filtration rate. At the dosage used, aztreonam proved effective for severe urinary tract infections caused by members of the family Enterobacteriaceae in pediatric patients.

Adolescent↗
PubMed1986

Immunocytochemical localization of actin in the sperm head of Talpa europaea (Insectivora).

Actin in the sperm head of Talpa europaea was observed by immunofluorescence and immunoelectron microscopy. The indirect immunofluorescence technique, using both anti-actin and DNase anti-DNase methods, showed a shining fluorescent band around the sperm head in some spermatozoa, whereas in others the fluorescence was found in the postacrosomal region. Since no labeling was detected in sperms treated with NBD-phallacidin, it is likely that mature mole sperms contain G-actin but not F-actin. The results of electron microscopy indicated the deposition of the anti-actin antibodies in two places in mole spermatozoa: the postacrosomal region and the nuclear segment of the acrosome. In the first case, the actin was localized in the space between the outer surface of the postacrosomal sheath and the plasma membrane; in the second one, the actin was localized in the space between the outer acrosomal membrane and the plasma membrane. The significance of the presence of actin and its role(s) during fertilization are discussed.

Actins↗
PubMed1986

Controlled study of the effects of tiropramide on biliary dyskinesia.

A controlled trial was carried out in patients with biliary dyskinesia to compare the effects of the new calmodulin-independent and antispastic drug tiropramide with those of imecromone. Forty patients were randomly divided into two groups, one treated with 300 mg tiropramide per day and the other with 1200 mg imecromone per day, both treatments lasting for 3 months. The results showed that tiropramide was significantly more effective in decreasing the number of attacks of pain and in improving pain and dyspepsia symptoms than imecromone. In subjects with delayed filling of the gall bladder during cholecystography, tiropramide but not imecromone was able to normalize the condition. These results confirm the antispastic synchronizing effect of tiropramide on the motor activity of the gall bladder and the sphincter of Oddi and indicate that it should be the drug of choice for treatment of motor disorders of the biliary tract.

Biliary Dyskinesia↗
PubMed1986

Differential diagnosis of Crohn's disease of the colon from ulcerative colitis: ultrastructure study with the scanning electron microscope.

Mucosal biopsies from patients with Crohn's disease and with ulcerative colitis were studied by scanning electron microscopy. Important abnormalities of the mucosal surface were found in both diseases. For Crohn's disease, the characteristic abnormality was loss of the regularity of the polygonal units, but with preservation of the mucosal integrity and of the normal mucosal design. For ulcerative colitis, the abnormalities were disorganization of the cells, signs of sloughing, and superficial erosions. Patients with Crohn's disease always had a significantly increased number of muciparous cells, while those with ulcerative colitis had obvious signs of decreased mucus production. The lesions of ulcerative colitis could be seen under the scanning electron microscope in mucosal areas that appeared normal endoscopically. We feel therefore that scanning electron microscopy of biopsy specimens from patients with inflammatory bowel diseases can be of great help in differential diagnosis.

Colitis, Ulcerative↗
PubMed1985

[A case of scleroderma with sclerodermic renal crisis and association with the Vogt-Koyanagi-Harada syndrome].

We report a case of scleroderma with "scleroderma renal crisis", (arterial hypertension, high plasma renin levels and impaired renal function) associated with a Vogt-Koyanagi-Harada syndrome which includes neurological, ophthalmic and cutaneous symptoms. This case is interesting not only because both syndromes are rare and have not previously been reported in association, but because it suggests a pathogenetic relationship between two autoimmune diseases.

Acute Kidney Injury↗
PubMed1985

[Angiomorphology of the ciliary body in diabetic disease].

The authors describe the pathological changes in the vascular structures of the ciliary body occuring in diabetes mellitus. The lesions consist of a quantitative reduction in the number of vessels and in modifications of diameter and arborisation. Changes include sectoral thinning, isolated and grouped aneuryms and marked tortuosity. These findings are thought to be constant in the diabetic patient and are probably involved in the various aspects of diabetic eye disease affecting other structures besides the ciliary body. The group of vascular changes in the ciliary body in diabetes may aptly be termed "diabetic ciliopathy".

Aqueous Humor↗
PubMed1984

Preparation and evaluation of [99mTc]DEPE as a cardiac perfusion agent.

Technetium-99m labeled bis(1,2-diethylphosphino)ethane was evaluated as a cardiac perfusion agent in mice, dogs and normal human volunteers. The agent produced as a single cationic compound was prepared by a simple kit type method and had a rapid myocardial uptake in animals. The cardiac uptake of the agent in dogs averaged 4.6% of administered dose and delineated left and right ventricles by in vivo imaging. In dogs with experimental myocardial infarction, the agent was distributed according to the regional myocardial blood flow, had excellent correlation with myocardial distribution of 85Sr microspheres (r = 0.96, 0.93)] and 201Tl (r = 0.91 and 0.83), and enabled us to detect perfusion defects by in vivo scintigraphy. The agent, however, failed to have a useful degree of cardiac uptake in humans.

Animals↗