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Biomedical subjects

F A Simeone

Publications and source records attributed to F A Simeone.

116 records · Page 7Linked to original sources
PubMedDate not supplied

Evidence that intraluminal pressure affects high potassium- and serotonin-induced contractions differently in the bovine middle cerebral artery: an in vitro study.

The effects of changing intraluminal pressure on contractions induced by 70 mM potassium (K+) and 10(-7), 10(-6), and 10(-5) M serotonin (5-HT) were studied in vitro in bovine middle cerebral arteries. Changes in vessel outside diameter in whole-mounted cylindrical sections of artery were detected with a photoelectric infrared device. High K+-or 5-HT (10(-5)M)-induced contractions peaked at 25 mm Hg and were significantly correlated with increasing intraluminal pressure between 25 and 175 mm Hg. Contractions induced with lower concentrations of 5-HT (10(-6), 10(-7) M), norepinephrine, and histamine peaked at 75 mm Hg but were not significantly correlated with rising pressure. Phentolamine (2 X 10(-6) M) added to the extraluminal bath had negligible influence on pressure's ability to affect K+- and 5-HT-induced contractions differently. Reducing bath temperature to 27 degrees C reduced the K+ response at each pressure, but similar temperature changes had little affect on the 5-HT-induced contractions. The K+ response became less sensitive to increasing pressure at low temperatures. Nifedipine (10(-7) M) almost totally eliminated K+-induced contractions, while significantly reducing the responses to all concentrations of 5-HT. The 5-HT responses appeared more sensitive to increasing intraluminal pressure in the presence of nifedipine. Maximum Ca++-induced contractions in the presence of 10(-5) M 5-HT and high K+ occurred at 25 mm Hg, while Ca++-induced contractions and Ca++-induced contractions in the presence of 10(-7) 5-HT or K+ plus 5-HT were maximum at 75 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

CT characteristics of intraventricular oligodendrogliomas.

Intraventricular oligodendrogliomas are a rare subset of oligodendrogliomas. Analysis of the clinical and CT characteristics of 11 cases in the literature and eight new examples revealed specific radiographic features, which included the presence of an anterior, midline mass within the lateral ventricles composed of clumped calcifications within a dense, enhancing matrix. Hydrocephalus is a constant feature, and these tumors present with signs of increased intracranial pressure. Eighteen of the 19 cases were benign and all were pure oligodendrogliomas, without admixture of other cellular elements. Intraventricular oligodendrogliomas grow slowly and are associated with prolonged survival but, due to their location, are difficult to remove and frequently require shunting. Subsequently developing symptoms, including herniation and death, are more frequently associated with complications related to hydrocephalus than with tumor growth. Intraventricular oligodendrogliomas can be distinguished from other intraventricular lesions by fairly specific CT characteristics. The ability to recognize them is helpful in prognosis, and awareness of associated complications related to hydrocephalus may assist in the long-term survival of affected patients.

Adolescent↗
PubMedDate not supplied

The anatomy of the lumbar sympathetic trunks in man (with special reference to the question of regeneration after sympathectomy).

Although possible to decentralize the sympathetic outflow to the leg, below the knee, by resecting only the third lumbar sympathetic ganglion, the likelihood of restoration of normal vasoconstrictor activity warrants a more extensive resection to include at least the second and third lumbar ganglia, and preferably the second, third, and fourth lumbar ganglia. When cross-over fibers are suspected or demonstrated following unilateral sympathectomy, the denervation should include the fourth and fifth lumbar ganglia. The first lumbar ganglion should be spared at least unilaterally if interference with reproductive function is to be avoided.

Arterial Occlusive Diseases↗