Development of a monoclonal antibody specific for beta/A4 amyloid in Alzheimer's disease brain for application to in vivo imaging of amyloid angiopathy.

We evaluated the efficacy of murine monoclonal antibodies (Mabs) targeted to beta/A4 amyloid for development of procedures for the in vivo identification of amyloid angiopathy (AA) in Alzheimer's disease (AD). Mabs to beta/A4 amyloid were prepared and screened for effectiveness in visualizing AA and senile plaques in postmortem AD brain sections. They were assessed again after enzymatic cleavage to produce Fab fragments and after labeling with 99mTc using a diamide dimercaptide ligand system. Modified and radiolabeled Fab fragments retained activity and specificity towards amyloid-laden blood vessels and senile plaques. A highly specific murine Mab, 10H3, was identified and characterized that fulfills criteria necessary for the development of a diagnostic imaging agent. Expansion and adaptation of these strategies may provide the methods and materials for the noninvasive analysis of AA in living patients, and permit assessment of the contribution of AA to the clinical and pathological features of AD.     

Multiple genetic alterations in malignant metastatic insulinomas

Proto-oncogenes, growth factors/receptors, and tumour suppressor genes were analysed in malignant metastatic insulinomas. Normal pancreas showed only a moderate immunoreaction for c-myc proto-oncogene and a strong reaction for insulin. Benign insulinomas were slightly or moderately positive for transforming growth factor a (TGFα), weakly positive for epidermal growth factor receptor (EGF-R), and strongly positive for c-myc and insulin. In malignant insulinomas, besides a strong immunoreaction for c-myc and TGFα, activation of c-K-ras and overexpression of p53 protein were found. Insulin reaction was moderate or strong. Three out of six malignant insulinomas displayed a c-K-ras point mutation at codon 12. All mutations were guanine to cytosine transversion, resulting in amino acid substitution, glycine to arginine. Mutations were present in metastatic insulinomas only. Patients with mutated c-K-ras oncogene had overexpression of p53 protein as well as c-myc and TGFα overexpression. Our results support the view that malignant progression is a consequence of more than one genetic lesion and suggest that activation of myc, TGFα, and ras genesα plays a role in a multistep process of tumour progression, perhaps serving as an initiating event.     

Use of a group-reactive and other monoclonal antibodies in an enzyme immunodot assay for identification and presumptive serotyping of aquatic birnaviruses.

A panel of monoclonal antibodies (MAbs) was prepared and used to develop an enzyme immunodot assay for the rapid identification and presumptive serotyping of aquatic birnaviruses. Comparison of the reaction patterns of these MAbs with representative virus isolates indicated that one MAb recognizes a serogroup-reactive epitope and can therefore be used for identification of all serogroup A aquatic birnaviruses, the predominant serotype worldwide. Other MAbs exhibited more restrictive specificities, permitting the presumptive serotyping of viruses of the three recognized serotypes and the identification of some individual strains. This assay, in which MAbs are used, is more efficient in terms of time, cost, and case of performance and provides significant advantages in specificity and standardization compared with currently used tests.     

Release of [(3)H]-L-glutamate by stimulation of nicotinic acetylcholine receptors in rat cerebellar slices

This is a neurochemical study which shows that nicotine acting through alpha7-containing nicotinic acetylcholine receptors promotes the release of [(3)H]-glutamate from rat cerebellar slices. Release evoked by half maximal concentration of nicotine (100 microM) was blocked by alpha-bungarotoxin and in a calcium-free medium, suggesting an effect mediated by an alpha7 receptor. Dihydro-beta-erythroidine and mecamylamine were effective only at very high concentrations, excluding the participation of heteromeric receptors. The effect of nicotine was partially blocked by inhibitors of glutamatergic receptors DL-2-amino-5-phosphonovaleric acid and 6-cyano-7-nitroquinoxaline-2,3-dione, indicating a glutamate-induced glutamate release. Nicotine-evoked response was dependent on activation of tetrodotoxin sensitive sodium channels. Therefore, here we show that glutamate released by stimulation of alpha7-containing nicotinic receptors, located preterminal and/or postsynaptically, evokes a further glutamate release in adult rat cerebellar slices.     

ONCOPROTEINS AND TUMOR SUPPRESSOR PROTEINS IN CONGENITAL SACROCOCCYGEAL TERATOMAS

Congenital sacrococcygeal teratoma SCT is the most common germ cell tumor of infancy and childhood with a female preponderance. Most SCTs are diagnosed at birth, are benign, and consist of fully differentiated, mature tissues. Tumorigenesis of SCTs remains poorly understood. Almost nothing is known about possible oncogene activation or tumor suppressor inactivation in these rare tumors. We describe the presence of various oncoproteins and tumor suppressor proteins in eight cases of congenital SCT. The following oncogenes were examined: ras family c-H-, c-N-, and c-K-ras , early genes fos, jun , and tumor suppressor genes p53 and nm23-H-1 . There was no relationship between the intensity of expression of these oncoproteins and tumor suppressor genes and the following parameters: tumor size, age, and survival of the patients. We did not observe any difference, however, between the expression of the examined oncogenes and tumor suppressor genes nm23 and p53 in immature and mature teratomas. Our findings suggest that the ras family of oncogenes, fos and jun oncogenes, and nm23 and p53 tumor suppressor genes are present in congenital SCT, indicating a possible role in genesis and development of these tumors.     

Differentiation of Aedes triseriatus (Say) from Aedes hendersoni Cockerell (Diptera: Culicidae) by restriction fragment length polymorphisms of amplified ribosomal DNA

Aedes triseriatus is the primary vector of LaCrosse (LAC) virus, which can cause encephalitis, especially in young children. Aedes hendersoni, a sibling species of Ae. triseriatus, has a salivary gland barrier to LAC virus and, therefore, is not considered a vector of this virus. Adults of Ae. triseriatus are morphologically indistinguishable from those of Ae. hendersoni, and the two species are sympatric in the eastern United States. A definitive method of identifying field specimens is an important part of any disease surveillance program, particularly in the case of LAC virus. This study identifies restriction enzymes that produce species-specific restriction fragment length polymorphisms (RFLPs) from amplified ribosomal (r) DNA. In addition, sequences of the internal transcribed spacers 1 and 2 and the 5.8S regions of the rDNA were used to confirm the RFLP patterns. This study is the first to compare nucleotide sequences from Ae. triseriatus and Ae. hendersoni.     

Cure of human carcinoma xenografts by a single dose of pretargeted yttrium-90 with negligible toxicity

A covalent conjugate (NR-LU-10/SA) was prepared between streptavidin (SA) and NR-LU-10, a mAb that binds an antigen expressed on the surface of most human carcinomas. NR-LU-10/SA was injected into nude mice bearing human tumor xenografts. Injection of biotinylated galactosyl-human serum albumin reduced the circulating levels of conjugate by 95%. Subsequent administration of (90)Y-1,4,7, 10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-biotin achieved peak uptake at the tumor within 2 hr while >80% of the radioactivity was eliminated in the urine. A single dose of 600-800 microCi of (90)Y-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-biotin produced cures in 10/10 mice with established (>200 mm(3)) s.c. human small cell lung or colon cancer xenografts and 8/10 cures in mice with human breast cancer xenografts without significant toxicity.     

Invasive cribriform breast carcinomas in patients with grade 1 and stage IIA (T2 N0 M0) breast cancer strongly express the v3 and v6, but not the v4 isoforms of the metastatic marker CD44

Patients with breast carcinomas of the invasive cribriform (IC) histological type often have excellent prognosis. Nevertheless, prognostic markers such as CD44v3, v4, and v6 isoforms have never been evaluated in this histological type. Cases seen between 1996 and 2006 at two major public hospitals in Kuwait were reviewed. We selected the cases which still had enough tissue in the paraffin blocks, had pure rather than mixed typical histological type, did not receive hormonal or any other type of therapy prior to or at the time the tumor was excised, and which were grade 1, and stage IIA (T2, N0, M0). This is to control for confounding factors that could affect the degree of tumor expression of the above isoforms. Sections were immunostained using a highly sensitive roxidase-anti-peroxidase kit, and scoring of immunostaining was performed in a semi-quantitative manner as established in the literature. An extensive expression of the CD44v3 and v6 isoforms was seen in 83.3% of the IC tumours, while 83.3% lacked the expression of the v4 isoform. A significant association between the histological type and degree of expression of CD44 isoforms was found only with the v3 isoform. The degree of expression of the v3 isoform was significantly different in the IC tumors as compared to the papillary, invasive lobular, and invasive ductal (NOS) ones. There was a significant negative correlation (rs= - 0.201) between the expression of the v4 and v6 isoforms. IC tumors seem to have a strong expression of the prognostic markers v3 and v6 isoforms of the transmembrane molecule CD44, and to lack the expression of the v4 isoform.