111In octreotide scintigraphy in the evaluation of head and neck lesions

PURPOSE: To evaluate indium 111 octreotide scintigraphy for the detection of suspected neuroendocrine lesions of the head and neck. METHODS: After receiving 6 mCi of 111In octreotide, 22 patients with suspected lesions of the head and neck were examined with both planar and single-photon emission CT (SPECT). Static images, obtained at 4 hours, included the head/neck, chest, abdomen, and pelvis. Additional SPECT images were obtained at 4 or 24 hours. Studies were compared with available conventional radiologic examinations (12 CT, 11 MR, and three angiographic studies) as well as with clinical and pathologic findings. RESULTS: Eighteen of the 22 patients had abnormal findings at scintigraphy. Eleven paragangliomas were seen in 10 patients, metastatic medullary thyroid carcinoma in three patients, thyroid adenoma in two patients, and Merkel cell tumor, carcinoid, and plasmacytoma in one patient each. Surgical confirmation was available in 13 patients. The smallest lesion detected was 1.5 cm. There was one false-positive and one false-negative examination. CONCLUSION: 111In octreotide scintigraphy is a useful imaging tool for the detection of primary and metastatic neuroendocrine tumors of the head and neck that are larger than 1.5 cm. This technique enables distinction of glomus tumors from other masses (such as neuromas) and can be used in the postoperative setting to distinguish scar from recurrent paraganglioma. Since it is an examination of the entire body, it has great utility for detecting multicentric paraganglioma and for screening patients with familial paraganglioma.     

Two complementary approaches to study peroxisome biogenesis in Saccharomyces cerevisiae: forward and reversed genetics

In order to investigate the mechanisms of peroxisome biogenesis and to identify components of the peroxisomal import machinery we studied these processes in the yeast Saccharomyces cerevisiae. The forward genetic approach has led to pas-mutants (peroxisomal assembly) which fall into 12 complementation groups and allowed to identify 10 of the corresponding wild-type PAS genes (PAS 1-7, 9, 11 and 12). Recent sequence analysis data of some of these genes are beginning to provide first hints as to the possible function of their gene products. The PAS genes and their corresponding mutants are presently used to address some important questions of peroxisomal biogenesis. Reversed genetics has been started as a complementary approach to characterize especially the function of peroxisomal membrane proteins. For this purpose we describe a technique to isolate highly purified peroxisomes. This led to the identification of 21 polypeptides as constituents of this organelle. Some of them are presently sequenced.     

Herpesvirus in atherosclerosis and thrombosis: etiologic agents or ubiquitous bystanders?

While it is well documented that the overactivation of ionotropic glutamate receptors leads to seizures and excitotoxic injury, little is known about the role of metabotropic glutamate receptors (mGluRs) in epileptogenesis and neuronal injury. Intracerebroventricular (i.c.v.) infusion of the group I mGluR specific agonist (R,S)-3,5-dihydroxyphenylglycine (3,5-DHPG) (1.5 micromol) to conscious rats produced severe and delayed seizures (onset at 4 hr) in 70% of the animals. The i.c.v. infusion of the group I mGluR non-selective agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) (2 micromol) produced a similar rate of severe seizures, but with an early onset (0.6 hr). The analysis of motor activity showed that 3,5-DHPG elicited higher central stimulatory action than did 1S,3R-ACPD. Histopathological analysis of the hippocampus showed that 3,5-DHPG produced severe neuronal damage mainly in the CA1 pyramidal neurons and, to a lesser extent, in the CA3. Although 1S,3R-ACPD infusion also induced a slight injury of the CA1 and CA3 pyramidal neurons, damage was greater in the CA4 and dentate gyrus cells. In conclusion, the in vivo activation of group I mGluRs with the selective agonist 3,5-DHPG produces hyperexcitatory effects that lead to seizures and neuronal damage, these effects being more severe than those observed after infusion of the non-selective agonist 1S,3R-ACPD.     

Bolted steel slip-critical connections with fillers: I. Performance

This paper reports the results of sixteen experiments of bolted slip-critical connections with fillers. Fifteen of the connections used oversized holes and one connection used standard holes. Such connections with oversized holes are commonly fabricated for use with structures such as long-span trusses, since the use of oversized holes allows erection in-place rather than first assessing fit-up on the ground. Filler plates are used to connect members of different depths or widths. The sixteen experiments reported herein highlight the behavior of bolted steel connections with oversized holes in which fillers are included and are undeveloped, partially developed, or fully developed. Both single-ply and multi-ply fillers are investigated, as are welded developed fillers, and specimens fabricated using either turn-of-the-nut or tension control bolts to pretension the connection. The results augmented with previous literature document the slip and shear strengths of these connections, propose formulas for assessing these strengths for the different conditions investigated, and provide recommendations for design of these types of connections.