Iron deficiency down-regulates the Akt/TSC1-TSC2/mammalian Target of Rapamycin signaling pathway in rats and in COS-1 cells

Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.     

Collagen synthesis activities of chondrocytes from histologically distinct zones of chick embryo tibia

Monolayer cultures of 12-day chick embryo chondrocytes from the regions of dividing (zone 1), elongated (zone 2), and hypertrophied (zone 3) chondrocytes in the tibial cpiphyseal growth plate were analyzed for their capacity to synthesize types II, IX, X, and XI collagens. Synthesis of types II and IX collagens was markedly elevated in the zone 2 culture, while type X collagen synthesis was maximal in zone 3. Type XI collagen was synthesized at low rates in all cultures, with some elevation of its rate in zones 2 and 3. In terms of mol percent of total collagen synthesis, types II and IX collagens decreased from zone 1 to zone 3, while type X collagen increased progressively. Thus, the composition of the extracellular collagens produced by the different zones changed markedly during chondrocyte differentiation. In addition, type X collagen was released exclusively into the culture medium, whereas type XI collagen was retained in the extracellular cell-associated matrix. In contrast, types II and IX collagens were found in both the culture medium and the cell matrix pools. Although types II and IX collagens showed similar changes during differentiation, the synthetic molar ratios of these two collagens varied from 3 to 18 in different cultures, suggesting that the synthesis of these two products is not tightly coupled in these cells.     

Autoradiographic Analysis of Radiolabeled Anti-carcinoembryonic Antigen Monoclonal Antibody CEA102 in Colorectal Cancer Using Computed Radiography

Anti-carcinoembryonic antigen monoclonal antibody (MAb) CEA102 was produced by immunization with purified CEA and the specific accumulation of radiolabeled CEA102 in colorectal cancers was investigated by autoradiography of surgical specimens using Fuji Computed Radiography (FCR). Five patients with colorectal cancer were injected intravenously with ¹³¹I-labeled intact CEA102 or its F(ab')₂. Primary tumor and liver metastases were successfully detected by external scanning with a gamma camera in 4 cases. Autoradiographic study of the surgical specimens using FCR showed predominant localization of ¹³¹I-labeled CEA102 in primary tumors and liver metastases in all cases. Even a small liver metastasis (0.5 cm) was clearly visualized in the autoradiogram by FCR. The pixel distribution curves of the density of the respective tissues in the autoradiograms by FCR showed the heterogeneity of the distribution of administered radiolabeled MAb in individual tumors, but the density of the tumors was higher than that of the normal tissues. In the quantitative distribution analysis of CEA102, the uptake of the primary tumor (mean 1.10%ID/kg) was ten-fold greater than that of the normal colon mucosa (mean G.10%ID/kg). These results revealed that the application of MAb has great potential in radioimmunodetection as well as in antibody-directed therapy.     

Tumor-specific binding of radiolabeled G-22 monoclonal antibody in glioma patients.

Iodine-131-labeled G-22 monoclonal antibody F(ab')2 fragment reaching specifically with a glioma-associated surface glycoprotein was administered to 12 glioma patients to investigate its use in radioimaging of intracranial gliomas. No immediate or delayed side effects were attributable to antibody injection. Nine patients received the radiolabeled complex intravenously. The images of low-grade gliomas were generally poor and disappeared within 4 days. High-contrast images were obtained beyond the 7th day in high-grade gliomas except one case in the pineal region. Three patients received intraventricular or intratumoral administration. Clear images of all tumors were demonstrated from the 2nd until later than the 7th day. One patient with cerebrospinal fluid (CSF) dissemination of brainstem glioma demonstrated negative CSF cytology after intraventricular administration.     

Effects of mosapramine (Y-516), a new dopamine D2 antagonist, on reverse tolerance after repeated administration of methamphetamine by means of the ambulation-increasing effect in mice]

Effects of mosapramine (Y-516), a new dopamine D2 antagonist, on reverse tolerance (sensitization) after repeated administration of methamphetamine (MAP; 2 mg/kg, s.c.) were investigated by means of ambulatory activity in mice; and they were compared with those of clocapramine (CCP), bromperidol (BPD) and chlorpromazine (CPZ). Y-516 (0.3, 1, 3 and 10 mg/kg, p.o.), CCP (3, 10 and 30 mg/kg, p.o.), BPD (0.1, 0.3 and 1 mg/kg, p.o.), CPZ (1, 3 and 10 mg/kg, p.o.) or 0.5% methylcellulose (MC; solvent, p.o.) were given to mice 30 min before MAP administration. The ambulatory activity was measured by tilting-type activity changes for 3 hr after MAP. These treatments were repeated 5 times at 3-4 day intervals. Then MAP alone was challenge-administered to all of these mice 3-4 days after the final administration. Marked reverse tolerance was produced after repeated administration of MC plus MAP. On the other hand, the ambulation-increasing effect of MAP was suppressed dose-dependently in groups pretreated with Y-516 or comparison-drugs, although the development of reverse tolerance was not completely inhibited after the repeated administration. In the challenge-administration of MAP, the ambulation-increasing effect was dose-dependently suppressed in the Y-516 group or the comparison-drug plus MAP group as compared with that in the MC plus MAP group.     

Anaplastic ganglioglioma with sarcomatous component: An immunohistochemical study and molecular analysis of p53 tumor suppressor gene

The present case report describes a case of ganglioglioma with a distinct sarcomatous component in the left temporal lobe of a 59‐year‐old Japanese man. Neoplastic neuroglial tissue contained both benign and anaplastic glial components with a MIB‐1 labeling index of 0.1% and 12.0%, respectively. Sarcomatous tissue adjacent to the anaplastic glial tissue was dominated by pleomorphic fibroblastic cells with a MIB‐1 labeling index of 10.8%. They were immunoreactive for smooth muscle actin, type IV collagen, and alpha 1 antitrypsin, but not for desmin and CD34. Interestingly, some of the sarcomatous cells were double‐positive for smooth muscle actin and GFAP. The p53 protein had accumulated in the anaplastic astrocytes and sarcomatous cells, but direct DNA sequencing of PCR products failed to detect any mutation in the p53 gene (from exon 4 to exon 10).     

Benzylpenicillin preparations can evoke a systemic anaphylactic reaction in guinea pigs

All of the five commercially available benzylpenicillin preparations obtained from different sources and a PcG preparation prepared by filtration of a commercial PcG on Sephadex G10 elicited the systemic anaphylactic reactions in guinea pigs which had been immunized with benzylpenicilloyl (BPO)-Ascaris extract conjugate (BPO-As) mixed with aluminum hydroxide gel. These preparations could evoke no such reactions in guinea pigs immunized with BPO-bovine gamma globulin conjugate (BPO-BGG) emulsified with complete Freund's adjuvant. The severity of the systemic anaphylactic reactions correlated significantly with the titers of either 8-day passive cutaneous anaphylactic (8-day PCA) reactions or 4-hr PCA reactions evoked with the same benzylpenicillin preparations. In vitro benzylpenicillin preparation contracted the tracheas of the guinea pigs immunized with BPO-As. These results indicated that the commercially available benzylpenicillin preparations have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with BPO-As mixed with aluminum hydroxide gel. Such guinea pigs represent an animal model for investigation of penicillin allergy.