[Analysis of keratin filament structural transformation in human epithelial cells].

Upon 2-3 hours cold treatment (0 degrees C), the keratin filaments of some PcaSE-1 cells and BEL-7404 cells are partly transformed into granular aggregates. But such structural transformation does not occur in HeLa cells and CNE cells. By rewarming (37 degrees C) cells within 15-30 minutes, this structural changes of keratin filaments in PcaSE-1 cells and BEL-7404 cells are readily reversed. In contrast, in HeLa cells and CNE cells, keratin filaments are transformed into granula aggregates during mitosis, but the keratin filament network in PcaSE-1 cells and BEL-7404 cells remained intact and encircled the developing mitotic spindle as the cells entered mitosis. Results suggest that the above two types of keratin filament structural transformation might be induced by different factors. Our results also indicate that: (1) PcaSE-1 cells treated with colchicine alone or with combination of colchicine and cytochalasin D does not cause granular aggregates of keratin filaments. However, after depolymerization of microtubules with colchicine, the response of the cells to cold treatment is intensified. (2) The aggregate formation during cold treatment is unrelated to whether epithelial cells contain two different type intermediate filaments or not. (3) Epithelial cells preextracted with Triton X-100 do not induce granular aggregate formation of keratin filaments upon cold treatment. (4) The structural transformation upon cold treatment may be a characteristic of keratin filaments of certain epithelial cell lines.

[Behavior of intermediate filaments in human epithelial cells during mitosis].

By indirect immunofluorescence microscopy and electron microscopy, we studied the behavior of intermediate filaments during mitosis in three human epithelial cell lines, derived from normal epidermis (PcaSE-1, from a cancer patient), stratified epithelium (CNE, from nasopharyngeal carcinoma) and simple epithelium (SPC-A-1 from lung adenocarcinoma) respectively. CNE cells and SPC-A-1 cells express two different intermediate filament systems; keratin filaments and vimentin filaments, but PcaSE-1 cells only express keratin filaments. The keratin filament system in PcaSE-1 cells remained intact and encircled the developing mitotic spindle as the cells entered mitosis. In contrast, in CNE cells and SPC-A-1 cells, keratin filaments appeared to disassemble into amorphous cytoplasmic bodies during mitosis. However, their vimentin filaments remained morphologically intact throughout mitosis. We propose; (1) The disassembly of keratin filaments in mitotic epithelial cells is more or less associated with the degree of their cell malignancy rather than with the abundance of keratin filaments in interphase. (2) Intermediate filaments may be involved in the positioning and/or centering of the spindle during mitosis. (3) The possible function of vimentin filament system in CNE cells is positioning and orientation of chromosomes.

[A novel monoclonal antibody against human keratins].

In this paper, we reported a novel monoclonal antibody against human keratins, R 6-2-14. The antigen used for immunization was derived from human callus, keratins in which traditionally are classified as "Soft" keratins. However, when we studied the tissue specificity of this antibody, it was found that it only reacted strongly with "Hard" keratins of various mammalian species, but no detectable cross-reactivity with any of the "Soft" keratins. This antibody may provide a useful tool for the study of hair regeneration, nail regeneration, corn pathology and differentiation of mammalian epidermal derivatives.

Rotavirus infection of the oropharynx and respiratory tract in young children.

Oropharyngeal aspirates were obtained from 89 infants hospitalized with respiratory illnesses accompanied or not by diarrhea and 33 control patients without the diseases. Rotavirus was detected from 25 of these patients by immunocytology, isolation of the virus in cultures of MA104 cells, or both. None of the control patients gave a positive result. The infection involves squamous cells and globlet cells probably originating from the oropharynx, and ciliated columnar epithelial cells from the respiratory tract. The virus from 2 specimens was propagated by repeatedly passaging in the cultures and found to have characteristic morphology of rotavirus. The electrophoretic patterns of the viral RNA extracted from them are closely similar to those obtained with the rotavirus genome extracted from the stool of the same patients. Repeated stool specimens were also obtained, and sera were paired from some of these subjects. All but one of the patients who gave a positive virology for their aspirates also showed a significant rise in the titres of common group A rotavirus antibody, neutralizing antibody against one or more of serotypes of rotavirus, or both. Patients who excreted rotavirus in their stools were younger and had significantly lower titres of rotavirus antibodies in their acute sera, than those who shedded the virus in the oropharynx but did not excrete the virus in repeated stool specimens. The prevalence of rotavirus in the oropharyngeal aspirates from these patients surpassed that of adenovirus, respiratory syncytial virus, influenza virus, and herpes simplex virus combined.