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Biomedical subjects

A Halama

Publications and source records attributed to A Halama.

At least 19 recordsLinked to original sources
PubMed1999

Metastasis of a renal cell carcinoma to the nose and paranasal sinuses.

We present a case of a metastasis of a renal cell carcinoma to the nose and paranasal sinuses. A 66 year old male patient developed a mass in his left nasal cavity and paranasal sinuses, five years after he underwent a left sided nefrectomy for a renal cell carcinoma. The histopathologic examination of the nasal mass showed metastasis of a renal cell carcinoma. A craniofacial resection was performed followed by radiotherapy.

Aged↗
PubMed1996

Contractile action of galanin analogues on rat isolated gastric fundus strips is modified by tachyphylaxis to substance P.

This study was undertaken to characterize the interaction of porcine galanin (Gal) and some of its analogues with their receptors on rat gastric fundus muscle strips. Gal, galantide (M15) and Gal(1-14)-[Abu8]SCY-I evoked concentration-dependent contractions of gastric smooth muscle strips. Reproducible effects were observed in concentrations of 1-300, 3-1000 and 100-3000 nM, respectively. Specific EC50 for the contractile effect equalled 13.70 and 187 nM. Hill's coefficient for Gal is 1.03 indicating an interaction of one Gal molecule with one receptor, fulfilling the criteria of classical receptor theory. For M15 and Gal(1-14)-[Abu8]SCY-I Hill's coefficients are different from 1, namely 0.73 and 1.56, pointing out that the principle of interaction of one drug molecule with one receptor may not apply. The contraction induced by 300 nM of Gal was not significantly modified by tachyphylaxis to substance P (SP). On the contrary the introduction of tachyphylaxis to SP decreased the contractile effects of M15 and Gal(1-14)-[Abu8]SCY-I by about 57.7 +/- 3% and 39.6 +/- 5%, respectively. The findings suggest that contractile actions of M15 and Gal(1-14)-[Abu8]SCY-I are probably not only due to their agonist activities at Gal receptors but may result from a subsequent stimulation of receptors for SP or release of endogenous SP.

Amino Acid Sequence↗
PubMed1996

Actions of galanin and some of its analogues on rat isolated gastric fundus.

The study was undertaken to characterize the effects of porcine galanin (pGal) and some of its analogues on rat gastric fundus muscle strips. pGal, galantide (M15) and pGal(1-14)-[Abu8]SCY-I evoked reproducible concentration-dependent contractions in concentrations of 1-300, 3-1,000 and 100-3,000 nM, respectively, with EC50 values of 13, 70 and 187 nM. Hill's coefficient for pGal is 1.03, indicating an interaction of one pGal molecule with one receptor, fulfilling criteria of classical receptor theory. For M15 and pGal(1-14)-[Abu8]SCY-I, Hill's coefficients are significantly different from 1, namely 0.73 and 1.56, so that one drug molecule may not interact with one receptor. The stimulatory effects of pGal were not modified by dibenamine 10 microM or glybenclamide 1 or 10 microM. Diltiazem 0.1, 1 and 10 microM, papaverine 0.1, 10 microM or dibutyryl cAMP (dib cAMP) 100 and 300 microM, blocked the contraction to pGal in a concentration-dependent manner, indicating an important role for the influx of extracellular calcium ions and regulation by cAMP the pGal-evoked contraction. Diltiazem, dibutyryl cAMP and papaverine were not competitive antagonists of pGal in the stomach smooth muscle.

Analysis of Variance↗
PubMed1996

Desensitisation of substance P decreases the contractile effect of M15 and Gal (1-14)-(Abu 8) SCY-I on the rat gastric fundus.

Tachyphylaxis to SP decreased the effect of M15 and Gal(1-14)-[Abu8]SCY-I on gastric smooth muscles, without effect on the action of Gal. These findings support our initial hypothesis: the action of M15 and Gal(1-14)-[Abu8]SCY-I on the smooth muscles may not only be due to their agonist activity at Gal receptors, but may result from a subsequent stimulation of receptors for SP and perhaps for other tachykinins as well, however, a possibility that Gal analogues release endogenous SP can not be excluded. Further studies involving a tachykinin antagonist (spantide) are in progress at the moment. [1].

Animals↗