Crotty, Thomas B.

AbstractThe etiology, prognosis, and optimal management of primary gastric carcinoids remain controversial. Records of 36 consecutive patients with gastric carcinoid (15 men) were reviewed retrospectively between 1975 and 1990. Follow‐up was complete in 97% of cases. Mean age at diagnosis was 58.4 years (range 24–82 years). The clinical presentations included anemia (72%), pain (69%), and carcinoid syndrome (11%). Associated autoimmune and endocrine abnormalities were common and included atrophic gastritis (67%), pernicious anemia (58%), hypothyroidism (39%), diabetes (19%), Addison's disease (6%), and hyperparathyroidism (6%). Lesions were nonantral in 78%, involving only the corpus in 42%, the fundus in 28%, and only the antrum in 8%; 42% were multiple. Urinary 5‐hydroxyindoleacetic acid (5‐HIAA) and serum gastrin levels were elevated in 17% and 50% of those tested, respectively. Histologic examination revealed that 28% of lesions were ≥2 cm, and 33% had liver metastases on presentation or developed them during follow‐up. Eight patients (22%) died of tumor with a median survival of 39 months. The presence of metastases, atypical histology, serosal involvement, and size > 2 cm were adverse prognostic factors. In patients without hypergastrinemia (n=6), 66% developed metastases, 60% had elevated 5‐HIAA, and 50% died of carcinoid tumor. In sharp contrast, those patients with hypergastrinemia and “typical” gastric carcinoids (n=15), metastases and death did not occur (p<0.003 and p < 0.005, respectively, compared with eugastrinemic patients). In the latter group (hypergastrinemia and typical histology), pernicious anemia was common (73%); solitary lesions and serosal penetration were seen comparatively less often (33% versus 100%, p<0.005 and 0% versus 33%, p<0.05, respectively); and no lesion measured > 2.0 cm compared to 66% in the group without elevated gastrin (p<0.002). No patient with hypergastrinaemia had elevated levels of 5‐HIAA. Overall survival at 5 and 10 years was 58% and 28%, respectively. Survival was 80% at 5 and 10 years in the hypergastrinemic group. Gastric carcinoid tumors that are histologically atypical, large (>2 cm), or present without elevated gastrin are potentially lethal and require aggressive therapy. In contrast, gastric carcinoids with typical histology and hypergastrinemia are rarely lethal, and conservative management with local excision and close observation is appropriate.

Nitric oxide (NO), synthesized from l -arginine by NO synthases (NOS), plays an essential role in the regulation of cerebrovascular tone. Adenoviral vectors have been widely used to transfer recombinant genes to different vascular beds. To determine whether the recombinant endothelial NOS (eNOS) gene can be delivered in vivo to the adventitia of cerebral arteries and functionally expressed, a replication-incompetent adenoviral vector encoding eNOS gene (AdCMVNOS) or β-galactosidase reporter gene (AdCMVLacZ) was injected into canine cerebrospinal fluid (CSF) via the cisterna magna (final viral titer in CSF, 10 9 pfu/ml). Adventitial transgene expression was demonstrated 24 h later by β-galactosidase histochemistry and quantification, eNOS immunohistochemistry, and Western blot analysis of recombinant eNOS. Electron microscopy immunogold labeling indicated that recombinant eNOS protein was expressed in adventitial fibroblasts. In AdCMVNOS-transduced arteries, basal cGMP production and bradykinin-induced relaxations were significantly augmented when compared with AdCMVLacZ-transduced vessels ( P < 0.05). The increased receptor-mediated relaxations and cGMP production were inhibited by eNOS inhibitors. In addition, the increase in cGMP production was reversed in the absence of calcium, suggesting that the increased NO production did not result from inducible NOS expression. The present study demonstrates the successful in vivo transfer and functional expression of recombinant eNOS gene in large cerebral arteries. It also suggests that perivascular eNOS gene delivery via the CSF is a feasible approach that does not require interruption of cerebral blood flow.