[Radioimmunolocalization of head and neck tumors with a new monoclonal antibody against the EGF receptor. Preliminary results]. / Radioinmunolocalización de tumores de cabeza y cuello con un nuevo anticuerpo monoclonal contra el receptor del EGF. Resultados preliminares.

OBJECTIVE: To show the results of Radioimmunodetection (RID) using Cuban monoclonal antibody (MoA) anti-egf-ior-egf-r3 labeled with 99mTc for the detection of primary tumors and/or metastases of head and neck epithelial malignant tumors. MATERIAL AND METHODS: Thirteen patients aged from 16-62 years (mean: 54.8 years) with primary tumors and metastases in the regional cervical lymph nodes were retrospectively evaluated. The labelling dose was 1480-2220 MBq (40-60 mCi). Planar images were performed after 10 minutes and together with SPECT images after 18-24 hours following MoA administration. The matrix was 128 x 128. SPECT images were reconstructed using the Butterworth 4/16 filter. A positive result was defined when the lesions were visualized. RESULTS: RID localized 11 of the known primary tumors in the 13 patients studied. In the two other patients, in whom the primary tumor site was unknown, cervical lymph node metastases were found. The results of 3 of the RID were false negative but in the other 10, RID was able to localize the primary tumor and cervical lymph node metastases. Sensitivity was 77 % and the predictive positive value was 100 %. CONCLUSIONS: The results of this study show that the Cuban MoA ior-egf-r3 can be employed for RID of primary head and neck tumors and their metastases. The radiation dose is adequate for RID.

Hexa-histidine tag as a novel alternative for one-step direct labelling of a single-chain Fv antibody fragment with 99m Tc.

From genetic material of hybridoma cells, we have generated a recombinant single-chain antibody fragment (scFv antibody) specific to carcinoembryonic antigen (CEA), which can substitute an intact murine monoclonal immunoglobulin G1 (IgG1) antibody, also developed by our group, and used in clinical practice for many years. In this paper, we examine a novel one-step method for direct 99mTc labelling of a recombinant anti-CEA scFv fragment through a C-terminal peptide tag containing a six-histidine sequence. This C-terminal peptide tag does not affect antigen binding, and was employed as a strategy for the one-step method of direct 99mTc labelling of a recombinant antibody fragment, based on the criteria of Zamora and Rhodes (Zamora PO, Rhodes BA. Imidazoles as well as thiolates in proteins bind technetium-99m. Bioconj Chem 1992; 3: 493-498). This is a novel technique for the rapid labelling of molecules, suitable for in vivo trials. The method yields >95% labelling efficiency without major effects on biological or in vitro stability.

[Pilot study with the monoclonal antibody IOR-C5 as a potential agent of radioimmunoscintigraphy in colorectal cancer]. / Ensayo piloto con el anticuerpo monoclonal ior-C5 como agente potencial de la inmunocentelleografía del cáncer colorrectal.

UNLABELLED: IOR C-5 is a G1 immunoglobulin type intact murine monoclonal antibody (MAb) that was developed in the Center of Molecular Immunology in Havana City, Cuba. In immunohistochemical studies, this demonstrated a significant affinity for the epithelial tissues so that it was used in a pilot clinical study to perform a radioimmunoscintigraphy of the colorectal primary tumors and their locoregional recurrences. It was labeled with 99mTc using the Schwarz method, with a > 95% performance. Planar images of the chest, abdomen and pelvis were performed at 10 minutes, 4-6 hours and 18-24 hours post-injection in the anterior and posterior projections and the SPECT was performed 4-6 hours and 18-24 hours post-injection of 1.85 GBq 99mTC. This study has aimed to verify in vivo the capacity of ior-C5 MAb to accumulate in the malignant colorectal lesions. ior-C5 accumulated in 5 out of the 7 patients who were studied and who were suffering from colorectal cancer or in whom there was suspicion of recurrence. There was a negative case of primary tumors, which was an adenocarcinoma in situ in a tubular-papillary adenoma. The second case with a negative radioimmunoscintigraphy was a true negative case. CONCLUSIONS: It can be concluded that even though the number of patients is quite low, ior-C5 fulfilled the expectations of recognizing the epitope expressed in colorectal tumors in an in vivo human environment.

99mTc-labeled antihuman epidermal growth factor receptor antibody in patients with tumors of epithelial origin: Part III. Clinical trials safety and diagnostic efficacy.

UNLABELLED: Monoclonal antibody (moAb) ior egf/r3 is an IgG2a that recognizes the epidermal growth factor receptor (EGF-R). The aim of this study was to evaluate the diagnostic efficacy of the 99mTc-labeled moAb ior egf/r3 for the detection of epithelial-derived tumors, their metastases and recurrences. METHODS: One hundred forty-eight adult patients (51 women, 97 men; mean age 53 +/- 13 y) who were suspected of having cancer of epithelial origin were administered 3 mg/50 mCi (1.85 GBq) 99mTc-labeled moAb ior egf/r3 by intravenous bolus injection. Planar anterior and posterior images of the lesion sites and suspected metastases were acquired at 2, 4, 6 and 24 h after injection, and SPECT images were scanned at 5 h postinjection, using a 360 degrees circular orbit with 64 images. The backprojection method was used for image reconstruction with a Hamming-Hann filter. RESULTS: Labeling efficiency was always greater than 98.5% +/- 2.1 %. No adverse reactions or side effects were observed. Results of the biopsy specimens showed that 85.1% (126/148) of the patients had tumors of epithelial origin, 14.2% (21/148) were negative and 0.7% (1/148) had non-Hodgkin's lymphoma. The sensitivity rate by organ was as follows: brain (8/8, 100%), digestive tract (10/11, 90.9%), head and neck (17/23, 73.9%), lung (52/62, 83.9%) and breast (16/18, 88.9%). Overall sensitivity, specificity, accuracy, and positive and negative predictive values of the immunoscintigraphic imaging were 84.2% (106/126), 100.0% (22/22), 86.5% (128/148), 100% (106/106) and 52.4% (22/42), respectively. New metastases not identified previously by other diagnostic methods were detected in the 50% of the patients. CONCLUSION: Immunoscintigraphy with 99mTc-labeled moAb ior egf/r3 could be a useful procedure for the diagnosis and follow-up of the patients with tumors of epithelial origin.

Usefulness of 99Tcm-tetrofosmin scintimammography in palpable breast tumours.

The aim of this exploratory study was to assess the potential of discriminating malignant from non-malignant lesions using 99Tcm-tetrofosmin scintimammography in the detection of palpable breast tumours. Nine patients with palpable masses were studied; seven had malignant lesions and two had non-malignant lesions. All diagnoses were established by fine-needle aspiration (FNA) biopsy cytology. Each patient received 925 MBq (25 mCi) 99Tcm-tetrosfosmin intravenously. Planar prone views were acquired in the right lateral, left lateral and anterior positions, and the axillary regions were included in the field of view. Scintimammography showed focally increased tracer uptake in seven patients with a positive FNA result. The two patients with a negative FNA result showed no increased uptake. We suggest that 99Tcm-tetrosfosmin shows promise as a radiopharmaceutical in the detection and discrimination of the nature of palpable breast tumours. Larger studies are required to confirm these findings.

[Uterine leiomyoma: pathology and epidemiology]. / Leiomioma uterino: patología y epidemiología.

Two hundred biopsy reports with uterine myoma histopathological diagnosis were studied 67% of the cases were between 41-50 years of age. Premenopausic patients showed an average number of myomas almost three times higher than the postmenopausic women. The most frequent myoma were those within the walls with a size less than 2 cm. Chronic inespecific cervixitis was the most frequent finding in the cervix pathology, with in 1.5% of the cases. In 2 cases (1%) endometrial adenocarcinoma was found. In 60.5% of the cases one or both tubes and ovaries were removed neither case had malignant alterations. In 51 cases (25.2%) the myoma presented some type of degeneration, the most frequent being the cellular type, 16 out of 200, which represented 8% of the cases; it was considered as presarcomatose type. Presurgical clinical behavior is discussed considering the analysis of these figures and the perspectives of the conservative treatment with the use of new no ablative technique.