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Biomedical subjects

M Sekimoto

Publications and source records attributed to M Sekimoto.

At least 145 records · Page 8Linked to original sources

Activated macrophage hybridomas secreting a cytotoxic factor.

Stable activated macrophage hybridomas were generated by somatic cell fusion between Propionibacterium acnes-induced peritoneal exudate cells and NS-1 myeloma cells. Five cell lines were obtained and each was cloned by limiting dilution; 59 clones were obtained. The cells of 2 clones (MP4-4 and MP4-8) which adhered to the culture dishes were selected for further analysis. These hybridomas exhibited non-specific esterase and beta-galactosidase intracellularly, and asialo GM1, Mac-1, Ia antigens and Fc-receptors on their cell surface. They did not, however, show phagocytic activity or secrete lysozyme. These hybridomas (MP4-4 and MP4-8) secreted the cytotoxic factor without any stimulation. Furthermore strong cytotoxic activity was found in ascites and sera from nude mice inoculated with these hybridomas. These activated macrophage hybridomas should be very useful in studies on cancer immunology and the physiology of macrophages.

Animals↗

Alterations to the bronchial and bronchiolar surfaces of adult mice after exposure to high concentrations of oxygen.

We have studied the effects of inhalation of 95 to 100% oxygen on the surface morphology of the bronchi and bronchioles of adult mice, using scanning electron microscopy. Denudation of cilia and truncation of the remaining cilia were commonly observed during high oxygen exposure. Bleb formation, a "moth-eaten" appearance of the non-ciliated cell surface and desquamation of unidentified cells were present in the bronchus after 96 hours of oxygen exposure. Deformation of non-ciliated cells, denudation of cilia, and flattening of the luminal surface were also seen in the bronchiole. For studying the recovery process from acute oxygen damage, we returned mice to room air after four days of high oxygen inhalation and killed them four, seven and 15 days after. There were more variable and complex changes of surface morphology in individual mice during the recovery phase. We observed flattening of the epithelial surface in the bronchiole and bronchus, and noticed that deformation of non-ciliated cells were seen even after 15 days. High oxygen inhalation causes severe morphological changes in the bronchial and bronchiolar mucosa, and those morphological lesions remain for at least two weeks after cessation of oxygen inhalation.

Animals↗

Low affinity nerve growth factor receptor gene co-segregates with decreased bodyweight and increased left ventricular weight in spontaneously hypertensive rats.

1. The sympathetic nervous system influences the cardiovascular and hormonal systems and sympathetic innervation is dependent on nerve growth factor (NGF). The NGF gene is linked genetically to high blood pressure in the spontaneously hypertensive rat (SHR) and there exists a mutation in the SHR low affinity NGF receptor (LNGFR) gene. 2. To determine whether the LNGFR mutation was linked genetically with cardiovascular phenotypes we studied an F2 population derived from SHR and normotensive Donryu (DRY) rats. 3. Mean arterial pressure (MAP), left ventricular mass (LVM) and related phenotypes were measured in 127 20 week old male F2 rats and correlated with the inheritance of the SHR mutation (S) and/or the DRY allele (D) of the LNGFR. 4. Analysis of variance revealed that the S mutation was associated with a significantly lower bodyweight in F2 rats (P < 0.0001). 5. The S mutation was associated with a significant (P < 0.007) increase in LVM:bodyweight ratio, but not with differences in right ventricular or kidney weights corrected for bodyweight. We found no association between MAP and LNGFR alleles or genotypes. 6. These results suggest that the mutation in the signal peptide of LNGFR may serve as a useful marker for the analysis of genetic factor(s) involved in the differential determination of body size and heart weight.

Alleles↗

Identification of a 7-cM region of frequent allelic loss on chromosome band 16p13.3 that is specifically associated with anaplastic thyroid carcinoma.

A total of 17 primary thyroid cancer specimens including seven anaplastic cancers, two papillary cancers adjacent to the anaplastic cancers, and eight papillary cancers were analyzed for loss of heterozygosity (LOH) on chromosome arm 16p. All tumors of anaplastic cancer showed LOHs at one or more loci, and a 7-cM region of the smallest deleted region was found on 16p13.3 between D16S423 and D16S406. This LOH was specifically found in the anaplastic cancer and not in the papillary thyroid cancer. Our present results suggest localization of the putative tumor suppressor gene on 16p13.3, which is likely to play an important role in the anaplastic transformation of thyroid cancer.

Adult↗

Epibulbar complex choristoma involving the bulbar conjunctiva and cornea.

A male infant was born with a fleshy mass between the temporal bulbar conjunctiva and cornea in the right eye. Four weeks after birth the patient underwent excision of the epibulbar tumor and a lamellar keratoplasty. Histopathologic examination of the excised tumor revealed cartilage, lobules of lacrimal gland, and adipose tissue, indicating an epibulbar complex choristoma. Although the graft remained almost completely transparent, right amblyopia ensued. Epibulbar complex choristoma involving the conjunctiva and cornea is a rare condition.

Adipose Tissue↗