Neurotensin (NT) has been postulated to act as a modulatory agent in the central nervous system. Besides its presence in mammalian brain, NT is produced by small cell carcinoma of the lung (SCLC) and cell lines derived from these tumors. Receptors have also been characterized in some SCLC cell lines leading to the suggestion that NT could regulate the growth of SCLC in an autocrine fashion similar to bombesin/GRP. Previously, we had reported that a 10 nM dose of NT and NT(8-13), but not NT(1-8), elevated cytosolic Ca2+, indicating that SCLC NT receptors may use Ca2+ as a second messenger. Using intact SCLC cells we report that time-course incubations with NT lead to the formation of the amino-terminal fragment NT(1-8) and small amounts of the C-terminal fragment NT(9-13). These fragments are formed by metalloendopeptidase 3.4.24.15 cleaving enzyme at the Arg8-Arg9 bond of NT. Significant levels of soluble 3.4.24.15 (10-17 nmoles/mg Pr-/min) are present in SCLC cell lines. Using the in vitro clonogenic assay we tested the effect of 0.5, 5.0 and 10.0 nM doses of NT, NT(1-8) and NT(8-13) on SCLC clonal growth. NT and the C-terminal fragment NT(8-13) stimulated colony formation whereas the N-terminal fragment did not. In summary, NT may function as a regulatory peptide in SCLC through the formation of peptide fragments.

Amino Acid Sequence↗

PubMedDate not supplied

Theophylline decreases sputum eosinophilia of asthmatics.

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Asthma↗

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[Surgical technics in tumors of the spine].

The authors have treated two hydatic cysts, three plasmocytomas, one chondrosarcoma, one osteogenic sarcoma and four metastasis at the level of the spine. The surgical procedures may be either palliative or curative. In metastatic lesions, posterior decompression was associated with internal fixation for prevention or improvement of neurological signs, providing more comfort during the patient's survival. Curative procedures were achieved a two-stages excision of the vertebra by anterior and posterior approachs, grafting and fixation using Harrington's rods. Surgery was followed by chemotherapy and roentgentherapy it should be started before onset on neurological troubles. Early results were gratifying flaccid paraplegia excluded.

Adolescent↗