Biological evaluation of 2-fluoro-2-[123I]iodo-mannose (FIM): biological evaluation of FIM.

This paper describes the biodistribution of a radio-iodinated analog of fluorodeoxyglucose (FDG). 123I-2-fluoro-2-iodo-mannose (FIM) was investigated as a potential single photon emission tomography (SPECT) imaging agent. We also compare the results with the observed distribution of the classical PET agent 18F-FDG and newly developed 18F-difluorodeoxyglucose (DFDG). Following radioiodination, the final product was stable in-vitro for 24 hrs. Mice showed a rapid blood clearance and deiodination of the 123I-FIM reflected by high stomach and thyroid uptake. Comparison with 18F-FDG and 18F-DFDG revealed a large discrepancy between the 18F labeled sugars and the 123I-FIM biological distribution. The iodinated product was not found to be a metabolic marker for in-vivo studies.

Retrieval of the species Alteromonas tetraodonis Simidu et al. 1990 as Pseudoalteromonas tetraodonis comb. nov. and emendation of description.

A polyphasic taxonomy study was undertaken of three strains of Pseudoalteromonas haloplanktis subsp. tetraodonis (Simidu et al. 1990) Gauthier et al. 1995. DNA was prepared from each of the strains and genomic relatedness was measured by DNA-DNA hybridization. Strains KMM 458T and IAM 14160T shared 99% genetic relatedness, but were only 48-49% related to the type strain of Pseudoalteromonas haloplanktis subsp. haloplanktis, IAM 12915T. The third strain, P. haloplanktis subsp. tetraodonis A-M, showed 83% genetic similarity with P. haloplanktis subsp. haloplanktis IAM 12915T and 32% with KMM 458T. From these results, it is concluded that strains KMM 458T and IAM 14160T comprise a separate species, originally described as Alteromonas tetraodonis, whereas strain A-M belongs to the species Pseudoalteromonas haloplanktis. Based on phenotypic and chemotaxonomic data, genomic fingerprint patterns, DNA-DNA hybridization data and phylogenetic analysis of 16S rRNA, it is proposed that the species Alteromonas tetraodonis be retrieved and recognized as Pseudoalteromonas tetraodonis comb. nov. (type strain IAM 14160T = KMM 458T).

Double-phase parathyroid scintigraphy in dogs using technetium-99M-sestamibi.

The purpose of this study was to evaluate the utility of double-phase parathyroid scintigraphy using 99mTc-sestamibi for detecting and localizing hyperfunctioning parathyroid glands in hypercalcemic dogs. Fifteen hypercalcemic dogs that underwent parathyroid scintigraphy were included in this study: 3 dogs with hypercalcemia of malignancy, and 12 dogs with hyperfunctioning parathyroid tissue (parathyroid adenoma or parathyroid hyperplasia). The presence of parathyroid adenoma or parathyroid hyperplasia was documented by histopathologic examination. In 3 dogs with hypercalcemia of malignancy, parathyroid scintigraphy was negative for hyperfunctioning parathyroid tissue and the scans were classified as true negative. Parathyroid scintigraphy correctly identified the presence and location of hyperfunctioning parathyroid tissue in only 1 of 6 dogs with a parathyroid adenoma. False positive and false negative results occurred in dogs with parathyroid adenomas. Parathyroid scintigraphy failed to detect hyperfunctioning parathyroid tissue in 5 of 6 dogs with parathyroid hyperplasia and were classified as false negative. False positive results were obtained in the remaining dog with parathyroid hyperplasia. Sensitivity of parathyroid scintigraphy for detecting and localizing hyperfunctioning parathyroid tissue was 11%, specificity was 50%, and overall accuracy was 27%. Positive and negative predictive value were 25% and 27%, respectively. Sensitivity for detection of parathyroid adenomas was 25%, and sensitivity for detection of hyperplastic glands was 0 %. Results of this study indicate that double-phase parathyroid scintigraphy does not appear to have acceptable accuracy in detecting hyperfunctioning parathyroid glands in dogs. Due to the poor sensitivity and specificity of the technique in dogs, parathyroid scintigraphy is not recommended for definitive identification of abnormal parathyroid glands as the cause of hypercalcemia in dogs.

Idiomarina gen. nov., comprising novel indigenous deep-sea bacteria from the Pacific Ocean, including descriptions of two species, Idiomarina abyssalis sp. nov. and Idiomarina zobellii sp. nov.

Two bacterial strains, KMM 227T and 231T, were isolated from seawater samples collected from the north-western Pacific Ocean at a depth of 4000-5000 m and were characterized using polyphasic taxonomy. Both were Gram-negative, psychrotolerant, heterotrophic, aerobic and required NaCl for growth (0.6-15.0%). The temperature for growth was 4-30 degrees C. Both strains were rod-shaped, with a single flagellum. However, strain KMM 231T revealed a single long fimbrium. Cellular fatty acids detected in the isolates were predominantly odd-numbered and iso-branched, with 15 and 17 carbons (ca. 70%). Also present were saturated and monounsaturated straight-chain fatty acids. Results of phylogenetic analyses, employing three tree-making methods, strongly indicated that the two strains formed a distinct lineage within a clade containing the genera Alteromonas, Colwellia and Pseudoalteromonas, in the gamma-Proteobacteria. The two strains shared 16S rDNA sequence similarity of 96.9% and genomic DNA relatedness of 27%; the latter was determined by dot-blot hybridization. The strains were differentiated by the presence of fimbria, production of chitinase, ability to grow on 15% NaCl and BIOLOG profiles. Given the polyphasic evidence accumulated in this study, it is proposed that the two deep-sea isolates be classified in the genus Idiomarina gen. nov., as Idiomarina abyssalis sp. nov. (type strain is KMM 227T) and Idiomarina zobellii sp. nov. (type strain is KMM 231T).

Potassium-channel opener cardioplegia is superior to St. Thomas' solution in the intact animal.

BACKGROUND: In isolated hearts, the potassium-channel opener pinacidil is an effective cardioplegic agent. This study tested the hypothesis that pinacidil is superior to St. Thomas' solution in the more clinically relevant intact animal. METHODS: Sixteen pigs were placed on full cardiopulmonary bypass. Hearts underwent 2 hours of global ischemia (10 degrees to 15 degrees C). Either St. Thomas' or 100 micromol/L pinacidil was administered every 20 minutes (10 mL/kg). Preischemic and postreperfusion slopes of the preload-recruitable stroke work relationship were determined. Changes in myocardial adenine nucleotide levels and cellular ultrastructure were analyzed. RESULTS: Pinacidil cardioplegia resulted in an insignificant change in the slope of the preload-recruitable stroke work relationship (40.6+/-2.1 mm Hg/mm before ischemia and 36.5+/-3.7 mm Hg/mm after ischemia; p = 0.466). In contrast, St. Thomas' solution resulted in a significant decrease in the slope after reperfusion (34.3+/-5.5 mm Hg/mm and 13.5+/-2.3 mm Hg/mm; p = 0.003). Adenine nucleotide levels, myocardial tissue water, and ultrastructural changes were similar between groups. CONCLUSIONS: Pinacidil ameliorated myocardial stunning associated with traditional hyperkalemic cardioplegia without causing significant differences in cellular metabolism.

Effect of ischemia and reperfusion on neutrophil accumulation in equine microvascular tissue flaps.

OBJECTIVE: To investigate neutrophil accumulation after ischemia and reperfusion (IR) in microvascular tissue flaps in horses. STUDY DESIGN: Randomized controlled experiment. SAMPLE POPULATION: A total of 8 horses between 1 and 10 years of age, 4 of each sex. METHODS: Control and experimental myocutaneous island flaps based on the superficial branch of the deep circumflex iliac vessels were dissected on each horse. Atraumatic vascular clamps were applied to the pedicle of the experimental flap for 90 minutes and then removed to allow reperfusion. Based on the assumption that rapid infiltration of neutrophils into affected tissues is a hallmark of IR injury, radiolabeled autogenous leukocytes were used to indirectly quantify neutrophil accumulation in flap tissues. Labeled leukocytes were administered through a jugular catheter 30 minutes before flap reperfusion. Biopsies were collected from each flap over a 6 hour postischemia time period; in group 1 (n = 4) from 0 to 6 hours postischemia, and in group 2 (n = 4) from 24 to 30 hours postischemia. Biopsies were examined scintigraphically and histologically for evidence of neutrophil infiltration. RESULTS: All control flaps survived and 6 of 8 experimental flaps survived. There was no significant evidence of acute neutrophil infiltration into flap tissues after reperfusion in either group. CONCLUSIONS: The results of this study suggest that equine myocutaneous flap tissues can survive a 90-minute ischemic period and reperfusion. No significant evidence of the occurrence of IR injury in flap tissues was found. CLINICAL RELEVANCE: The reasons for the previously reported failures of equine free tissue transfer remain uncertain, but they do not appear to be caused by neutrophil mediated injury associated with ischemia and reperfusion.

Relative distribution of blood flow in rats during surface and submerged swimming.

The relative distribution of blood flow was investigated in conscious rats with a radiological imaging technique that utilizes technetium-99m ethyl cysteinate dimer (99mTc-ECD). The objective of the study was to determine the effects of locomotory activity on the distribution of blood flow during a dive response. We compared the relative distribution of systemic flow in rats at rest, surface swimming and during periods of voluntarily initiated underwater swimming. The pattern of blood flow differed considerably between the three groups of rats. In resting controls, blood flow was widely distributed throughout the whole body with the thoraco-abdominal region receiving the largest fraction of cardiac output. During surface swimming blood shifted towards the exercising limbs, while during underwater swimming systemic blood flow was largely restricted to the head and thorax. However, the active front and hind limbs were not rendered totally ischemic. This suggests that the demands of exercising skeletal muscle partially over-ride the peripheral vasoconstriction during asphyxic diving in conscious rats. Furthermore, relative blood flow to the head increased during underwater swimming, which supports the view that there is a preferential maintenance of blood flow to the brain.

Use of technetium Tc 99m sestamibi for detection of a parathyroid adenoma in a dog with primary hyperparathyroidism.

Double-phase parathyroid gland scintigraphy, using technetium Tc 99m sestamibi, correctly identified the existence and location of a parathyroid adenoma in a dog with primary hyperparathyroidism. The parathyroid adenoma was removed surgically 2 days after scintigraphy. An area of focal radionuclide uptake persisted in the region corresponding to the left external parathyroid gland in the delayed-phase image. Delayed-phase images from 3 healthy dogs and a dog with hypercalcemia of malignancy caused by lymphoma did not reveal an area of persistent radiotracer uptake. Double-phase parathyroid gland scintigraphy, using 99mTc-sestamibi, is a simple, rapid, noninvasive test, which can be used for detection and localization of parathyroid adenomas in hypercalcemic dogs. It also can help to differentiate these dogs from dogs with hypercalcemia of malignancy.

Establishment of a rat colonic carcinoma model for study of immunoreagents against the human tumor-associated TAG72 antigen.

TAG72 originally defined by the mouse B72.3 antibody is a mucin-like, human tumor-associated antigen present in more than 85% of human colonic adenocarcinomas. Establishment of a tumor model expressing the TAG72 antigen in immunocompetent animals would be of great benefit in evaluating the therapeutic efficacy and studying anti-tumor immune mechanisms of anti-TAG72 immunoreagents. In this study, we screened 6 animal tumor cell lines including 3 derived from mouse colonic adenocarcinomas (MCR-26, MCR-38-LD and CA-51), 1 from mouse ovarian adenocarcinoma (MOT), 1 from rat colonic adenocarcinoma LMCR, and 1 from rat mammalial adenocarcinoma (R3230AB) for TAG72 expression by using the B72.3 antibody. Immunohistochemistry disclosed significant amounts of TAG72-expression in the dimethylhydrazine-induced BDIX rat colonic adenocarcinoma LMCR. The rat TAG72 antigen purified from rat LMCR tumors showed strong immunoreactivity for the B72.3 antibody in ELISA analysis and displayed a smear band of high molecular weight in Western blotting, which is similar to the human TAG72 antigen purified from human LS174T colonic adenocarcinoma. In addition, the iodinated B72.3 antibody was able to localize LMCR tumor in BDIX rats. Therefore, this rat LMCR model should be useful in studying human colonic cancer, especially in evaluating the therapeutic efficacy of anti-TAG72 immunoreagents such as the recombinant fusion proteins possessing the anti-TAG72 antibody fragment and the cytokine moiety.

Immunolocalization of hepatic metastases of human colonic cancer by chimeric anti-TAG72 antibody in SCID mice.

TAG72 is a well-characterized, human tumor-associated antigen present in > 85% of human colonic cancers. In this study, we established an animal model of hepatic metastases of human colonic carcinoma. The high-mucin variant cell line, designated HM7, was derived from the human colonic carcinoma cell line LS174T. Following intrasplenic injection, HM7 was able to induce much greater hepatic metastases in SCID mice compared to its parental cell line LS174T. Numerous hepatic metastases were evident 18 days subsequent to the intrasplenic injection of tumor cells. Using the chimeric anti-TAG72 antibody ccM4, immunohistochemistry demonstrated strong expressions of the TAG72 antigen in these metastases. Our biodistribution and imaging data also showed that the radiolabelled ccM4 antibody was able to localize hepatic metastases in the SCID mice. Based upon these findings, w anticipate that the herein described SCID mouse model will prove most useful in studying hepatic metastases of human colonic carcinoma by using anti-TAG72 therapeutic immunoreagents.

High-affinity chimeric anti-(colorectal carcinoma) antibody correlated to enhanced tumor targeting in biodistribution and imaging.

The genetically engineered chimeric cB72.3m4 and cB72.3m12 antibodies recognize the same tumor-associated TAG72 antigen. The high-affinity cB72.3m4 antibody had an approximately 18-fold higher affinity constant for the TAG72 antigen than the low-affinity cB72.3m12 antibody. The relationship between antibody affinity and tumor targeting was studied by using these two antibodies. In biodistribution and imaging studies in athymic mice bearing LS174T human colon cancer xenografts, the radiolabelled high-affinity cB72.3m4 antibody was rapidly cleared from the blood, whereas the low-affinity cB72.3m12 antibody had slower blood clearance. The data showed that the high-affinity cB72.3m4 antibody appeared to localize more in tumors (based on tumor:normal-tissue ratios) than did the low-affinity cB72.3m12 antibody, and enhanced the target-to-nontarget image contrast. This study provides evidence that the high-affinity chimeric antibody cB72.3m4 may be useful in both immunodetection and immunotherapy of cancer.

Immunoscintigraphic detection of primary and metastatic spontaneous canine osteosarcoma with F(ab')2 fragments of osteosarcoma-associated monoclonal antibody TP-1.

Monoclonal antibody TP-1 has been shown to bind selectively to human and canine osteosarcoma cells in vitro using immunohistochemical stains. This report describes the in vivo administration of radioiodinated F(ab')2 fragments of monoclonal antibody TP-1 in dogs with primary and/or metastatic spontaneous osteosarcoma. Two dogs were injected with 131labeled F(ab')2 TP-1 and two dogs were injected with 123labeled antibody fragments. Immunoscintigraphy successfully demonstrated the radiolabeled antibody fragments in 6/6 known primary or metastatic lesions and in addition detected 4 metastatic lesions not diagnosed by conventional radiographs. Concurrent imaging of 99mTc labeled autologous erythrocytes in two dogs confirmed that the accumulation of radiolabeled antibody fragments was independent of the blood pool. There was no immunoscintigraphic evidence of localization of radioiodine to normal organs or tissues other than those expected to accumulate free iodine. The present study has demonstrated the potential of monoclonal antibody TP-1 F(ab')2 fragments for early detection of metastatic spread of spontaneous osteosarcoma.

Technetium 99m pentavalent dimercaptosuccinic acid and thallium 201 in detecting recurrent medullary carcinoma of the thyroid.

To compare the effectiveness of thallium chloride 201 and technetium 99m pentavalent dimercaptosuccinic acid in evaluating medullary carcinoma of the thyroid (MCT), eight patients with a history of MCT underwent imaging with both radiopharmaceuticals. Thallium 201 consistently gave superior images, as well as providing one less false-negative scan. Positive scans were obtained in patients with elevation of basal calcitonin levels to more than 1,000 ng/L. All of the patients with positive scans had clinical evidence of local recurrence. Improved imaging with thallium 201 was obtained by early scanning.

Immunohistochemical staining and radionuclide imaging of canine tumors, using a monoclonal antibody recognizing a synthetic carbohydrate antigen.

The in vitro and in vivo binding of a monoclonal antibody (MAB) that recognizes a tumor-associated carbohydrate antigen was studied in dogs. Monoclonal antibody 155H.7 was raised in response to innoculation of mice with beta-galactose(1-3)beta N-acetylgalactosamine conjugated to human serum albumin. Avidin-biotin-complex immunohistochemical staining of cryostat sections of normal and neoplastic canine tissue specimens revealed heterogenous binding of MAB 155H.7 to the cells of many canine mammary and lung carcinomas and homogenous staining of many sarcomas, including osteogenic sarcoma. In addition, there was variable staining of a variety of normal tissues including some ductual epithelium, peripheral nerve fibers, and some endothelial cells and fibroblasts. Immunoscintigraphy with 131I-labeled MAB 155H.7 was used to study the in vivo distribution of the antibody. The 131I-labeled MAB 155H.7 was administered to 1 clinically normal dog, 7 dogs with osteogenic sarcoma, 1 dog with undifferentiated sarcoma, and 2 dogs with mammary tumor. Scintigraphy revealed concentration of radioactivity in 8 of 10 tumor sites within 24 hours after MAB administration. The ratio of 131I in tumor sites to 131I in the surrounding normal tissues, compared with the similar ratio of 99mTc-labeled erythrocytes ranged from 1.1 to 4.3, in tumor vs normal tissue with a mean value of 2, confirming tumor localization of the radiolabeled MAB in excess of that associated with enhanced tumor vascularization.