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J Teixidó

Publications and source records attributed to J Teixidó.

63 records · Page 4Linked to original sources
PubMedDate not supplied

Integral membrane glycoprotein properties of the prohormone pro-transforming growth factor-alpha.

Transforming growth factor-alpha (TGF-alpha) is a mitogenically active polypeptide hormone produced by acutely proliferating neoplastic and embryonic tissues. Molecular cloning of TGF-alpha cDNA from human and rat has indicated that this factor is synthesized as part of a larger precursor, proTGF-alpha. An intriguing feature of proTGF-alpha is that it contains a sequence of 24 hydrophobic amino acids following the bioactive TGF-alpha sequence. Similar hydrophobic sequences present in transmembrane proteins are cotranslationally anchored into the phospholipid bilayer of the rough endoplasmic reticulum, suggesting the possibility that pro TGF-alpha might be an integral membrane protein. Other secretory proteins including all known prohormones lack membrane anchoring sequences and are completely translocated across the endoplasmic reticulum membrane. To address the question of whether proTGF-alpha is as an integral membrane protein we have translated rat proTGF-alpha mRNA transcripts in the presence of rough endoplasmic reticulum membrane vesicles. The results indicate that proTGF-alpha is synthesized as an integral membrane glycoprotein. The 50-amino-acid TGF-alpha sequence in proTGF-alpha is exposed to the fluid extracellular phase where it can be released after cleavage by the appropriate enzyme.

Amino Acid Sequence↗
PubMedDate not supplied

[Neuropathy due to necrotizing vasculitis: a study of the clinical anatomy, neurophysiological characteristics, and clinical course of the disorder in 27 patients].

INTRODUCTION: Peripheral neuropathy is usually one of the initial symptoms of necrotizing vasculitis. Early diagnosis is essential for good prognosis. OBJECTIVE: To determine which parameters are useful for early diagnosis and selection of tissue for biopsy. PATIENTS AND METHODS: We analyzed the clinical, biological, electromyographic and anatomopathological characteristics of 26 patients with necrotizing vasculitis and peripheral neuropathy. RESULTS: Twelve patients had panarteritis nodosa, three Churg Strauss syndrome, two Wegener s syndrome, two disseminated lupus erythematosis, one sarcoidosis and one Walderstrom s macroglobulinemia. Fifteen patients had multineuritis and the remainder distal mixed polyneuropathy which was symmetrical in three cases. In five cases biopsy was normal. Sural nerve biopsy showed the diagnosis to be correct in 20% of the patients. However, when this was done on a neurophysiologically affected nerve, the tissue was seen to be altered in 61%. Biopsy of the gastrocnemius increased the degree of usefulness to 73% when electromyographic anomalies were detected in this muscle. CONCLUSIONS: Neurophysiological study is essential for detection of alterations in patients clinically suspected of having necrotizing vasculitis, even in cases where there is apparently no neuropathy. We recommend biopsy of the gastrocnemius muscle as the first choice in cases where sural nerve neurography is found to be normal. If the sural nerve is not normal, it is the site of choice for biopsy, and muscle biopsy is the site of second choice. When both biopsies are normal, renal biopsy should be considered to establish the diagnosis, as a third alternative.

Biopsy↗