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Biomedical subjects

G Palumbo

Publications and source records attributed to G Palumbo.

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

[Non-steroidal anti-inflammatory agents. IV. Synthesis and pharmacologic activity of aroylthiopheneacetic acids with a pyrrole group].

The synthesis of new antiinflammatory aroylthiopheneacetic acids bearing a pyrrole moiety is described. These compounds can be regarded as analogues of thiaprofen and related isosteres. The antiinflammatory activity of the new pyrryl derivatives has been evaluated in comparison with indomethacin, tolmetin and the unknown 5-(2-chlorobenzoyl)thiophene-2-acetic acid. Among tested derivatives the compounds containing the pyrrole ring were devoid of analgesic-antiinflammatory activities.

Animals↗
PubMed1985

Prediction of the secondary structure of the carboxy-terminal third of rat thyroglobulin.

A secondary structure prediction has been made using the available primary sequence data of the proposed carboxy-terminal of rat thyroglobulin. The model predicts 22% alfa-helix, 28% beta-structure and 17% beta turns. Out of the 8 possible carbohydrate acceptor-sites (Asn-x-Ser/Thr), 3 (residues 136, 368, 782) are associated with peptide sequences which favour the formation of beta-turn or loop-structures and are located in high hydrophilic regions. The entire sequence is predicted to be made up of two domains: one of them is highly structured, contains the hormonogenic sites, a cluster of tyrosines and at least one carbohydrate acceptor site.

Amino Acid Sequence↗
PubMed1985

Cross-linking with dimethylsuberimidate to study thyroglobulin conformation.

The present investigation demonstrates that the cross-linking agent, dimethylsuberimidate, is an usefull tool to study thyroglobulin structure. In fact, while reproducible and discrete polymerization products are obtained in strictly controlled conditions, valuable information on the native assemblage of thyroglobulin subunits and the effects of its major post-translational modification (iodination) on its structure, are reported.

Animals↗
PubMed1985

[New psychotropic agents. 2. Synthesis and pharmacologic activity of derivatives of 5H-pyrrolo[1,2-b][1,2,5]benzotriazepines].

Bischler-Napieralski intramolecular cyclization of N-(2-aroylaminophenyl)-N-methyl-1H-pyrrol-1-amines and reaction of arylaldehydes on N-(2-aminophenyl)-N-methyl-1H-pyrrol-1-amine furnished 11-aryl-5-methyl-5H-pyrrolo[1,2-b][1,2,5]benzotriazepines and 11-aryl-10,11-dihydro-5-methyl-5H-pyrrolo[1,2-b][1,2,5]benzotriazepin es respectively. The latter reaction required in some cases the use of p-toluenesulphonic acid as a catalyst. The new tricyclic derivatives described were tested for pharmacological evaluation of their psychotropic activity.

Animals↗
PubMed1984

Molecular organization of 19 S calf thyroglobulin.

Controlled freezing and thawing of 19 S calf thyroglobulin resulted in a specific and reproducible breakdown of the protein. Beside the elementary chain (300,000 Da), new, discrete bands are revealed by gel electrophoresis in sodium dodecyl sulfate under reducing conditions. These new species consist of a major peptide of 100,000 Da and several faster-migrating bands. Most of these polypeptides were purified by preparative gel electrophoresis and individually digested in formic acid with CNBr. A comparative gel electrophoresis under denaturating and reducing conditions of (i) the fragments obtained from the native protein, (ii) the electrophoretically purified elementary chain, (iii) the 100,000-Da peptide, and (iv) a smaller fragment (of about 50,000) was performed. It revealed a very close homology among the peptide maps of the intact 19 S, the elementary chain, and the 100,000-Da peptide. Furthermore, it was shown that the digestion products of the smaller fragment, present in the peptide map of the native protein, were absent in both the elementary chain and the 100,000-Da species. These results support the idea that calf thyroglobulin, even though it has an apparently complex molecular organization, contains structural motifs which are repeated in the elementary chain.

Animals↗
PubMed1984

[Non-steroidal anti-inflammatory agents. III. Synthesis and analgesic-anti-inflammatory activity of 4-(pyrrol-1-yl)phenylacetamides and 4-(pyrrol-1-yl)phenethylamines].

Preparation of some 4-(pyrrol-1-yl)phenylacetamides and 4-(pyrrol-1-yl)phenylethylamines starting from 4-(pyrrol-1-yl)phenylacetic acid is reported. The new compounds were tested as analgesic-antiinflammatory agents. Data from pharmacological screening indicate 1-[4-(pyrrol-1-yl)phenylethyl]piperidine as the most active substance.

Acetamides↗
PubMed1983

Iodine-induced changes in thyroglobulin half-sized subunits.

The two half-sized subunits of 19 S thyroglobulin have been separated and analyzed. They share the same peptide composition and carbohydrate content. The only difference was the iodine level, which was about three times higher in the faster electrophoretic subunit.

Animals↗
PubMed1983

A four- to sixfold enhancement in sensitivity for detecting trace proteins in dye or silver stained polyacrylamide gels.

A very simple procedure which enhances sensitivity in visualizing proteins stained by all standard procedures in polyacrylamide gels is described. The process, based on the use of concentrated polyethylene glycol 6000 solutions, produces a conspicuous, reversible, and uniform size reduction of gels. The entity of the reduction depends principally on the polyethylene glycol 6000 concentration and on the acrylamide content of gels. Using an appropriate polyethylene glycol 6000 concentration, it is possible to regulate the final size and then the sensitivity as needed. Depending upon the above conditions it is possible to increase the sensitivity by a factor of 4-6 or more. Reduction of the gel volume by such a factor may eliminate the need for the cumbersome and frequently impossible preconcentration of samples. Besides the Coomassie blue stained gels, silver stained gels may also be treated in a similar manner with a consequent further enhancement in sensitivity. In addition, gels containing radiolabeled materials can be autoradiographed in times proportionally shorter, without significant sacrifice of resolution.

Coloring Agents↗
PubMed1983

Evidence for homologous repeating segments within the elementary polypeptide chain of guinea pig thyroglobulin.

In this paper we report on the peptide maps of the three polypeptides produced by reduction of denatured 19-S thyroglobulin from guinea pig. These maps were obtained by both chemical cleavage (CNBr) and by limited enzymatic proteolysis (Staphylococcus aureus SV 8 protease). Analysis of these peptides showed a strict correspondence among the electrophoretic bands produced by cleavage of the guinea pig thyroglobulin components. These results support the idea that thyroglobulin, even though it has an apparently complex molecular structure, contains polypeptide sequences which are repeated in the elementary chain. Since similar structures should correspond to similar functions, each of these regions may work as a functional domain for the biosynthesis of the thyroid hormones.

Animals↗
PubMed1983

Calcium-induced changes in thyroglobulin conformation.

Polyethylene glycol solutions (10% w/v) were used to detect the effect of mono- and divalent cations on some properties of thyroglobulin. It is shown that in presence of 10% w/v polyethylene glycol in 0.01 M Tris-HCl, pH 7.5, calcium (less than 0.05 M) modifies the solubility, the sedimentation rate, and the Stokes' radius of thyroglobulin, while monovalent cations up to 0.6 M do not effect any of these properties. These findings can be explained by an increase in molecular compactness of thyroglobulin. Furthermore, it was shown that a synthetic polymer, polyethylene glycol, could be used to detect conformational changes.

Animals↗
PubMed1982

The effects of iodination on the polypeptide heterogeneity of thyroglobulin.

19 S thyroglobulins from several mammals were prepared under conditions designed to minimize endogenous proteolytic activities. The purified iodoproteins were then fractionated by RbCl isopycnic gradient centrifugation and fractions of varying iodine content analyzed by SDS-polyacrylamide gel electrophoresis. The dependence on the iodination level of molecular dissociability, previously reported in preparations "markedly' differing in their iodination degree, has been now ultimately assessed in all species investigated and demonstrated even for fraction differing from each other only by a few iodine atoms. Upon reduction fractions across the isopycnic gradients showed the occurrence of discrete electrophoretic bands faster than the 300,000 Da subunit: the relative amount of these peptides has been found to be linearly related to the iodine content of the molecules analyzed. This behaviour has been observed in all animal species investigated. In conclusion, our data suggest that iodination, beside the well-documented effects on thyroglobulin conformational properties, may also affect its "apparent' polypeptide chain composition. The origin of such heterogeneity is discussed.

Animals↗
PubMed1982

Metergoline in the management of hyperprolactinemic amenorrhea and anovulation.

84 patients with elevated serum PRL levels, ranging from 25 to 253 ng/ml, were treated with an antiserotonin agent, metergoline, at the dose of 12 mg/day for 90 days. The clinical complaint was of amenorrhea in 70 cases (plus galactorrhea in 44 cases) and of anovulation in 14 cases (plus galactorrhea in 6 cases). Hyperprolactinemia was due to a pituitary adenoma in 18 cases; in 53 cases it was of unknown origin, while in 7 cases it followed treatment with neuroleptics or with oral contraceptives and in 6 cases it followed a puerperium. In patients with amenorrhea, metergoline induced the appearance of menses in 61 cases (94%), and of ovulation in 46 cases (82%). In 13 of the 14 patients with anovulation, ovulation was restored. Galactorrhea disappeared in 40 out of 50 patients. Metergoline normalized serum PRL levels (less than 20 ng/ml) in 46 cases and significantly reduced serum PRL levels in all but 3 of the remaining patients. In spite of suggested nonhormonal contraceptive measures, 14 patients became pregnant; 2 had abortions and the remaining 12 patients completed by vaginal delivery, uneventful pregnancies. These results indicate metergoline as a safe and effective drug in the management of hyperprolactinemic amenorrhea and anovulation. 49 patients were followed for 2 additional months, receiving no treatment (24 cases) or metergoline at a reduced daily dosage (8 mg/day, 25 cases). Within 60 days, 60% of the first group had relapse of the clinical condition and a rebound elevation of serum PRL levels while only 20% of the second group experienced relapse of amenorrhea and rebound elevation of serum PRL levels (p less than 0.01).

Amenorrhea↗
PubMed1981

Polypeptide chain composition of thyroglobulin.

It is known that thyroglobulin can be dissociated into a component which appears to be a half molecule (12 S) of the undissociated molecule (19 S). In the present work, these two molecular species were isolated with a high degree of purity by preparative gel electrophoresis in sodium dodecyl sulfate and were individually reduced. The reduction pattern of the 12 S form displayed only two closely migrating bands, both having an apparent Mr near 330 000, whereas the undissociated (covalently linked) 19 S form showed a complex pattern consisting of, besides the 330 000 doublet, nonreducible material and several faster bands, resembling the pattern of the unfractionated protein. The origin of the faster-moving peptides is not known. These results have been obtained with both hog and rat thyroglobulin.

Animals↗