Involvement of a nucleolar component, perichromonucleolin, in the condensation and decondensation of chromosomes

A component of the nucleolar material, perichromonucleolin (PCN), was identified by a specific antiserum against nucleoli obtained from a scleroderma patient. The distribution and changes of PCN during the mitotic cycle were followed using this antiserum and indirect immunofluorescence microscopy. Based upon the behavior of PCN during mitosis, it could be differentiated into chromosomal and nonchromosomal portions. During prophase the former gradually associates with the surface of the condensing chromosomes and forms the coat or pellicle around the metaphase and anaphase chromosomes. This pellicle PCN is carried by the anaphase chromosomes to the daughter nuclei. During the time from telophase to interphase, the pellicle PCN dissociates from the decondensing chromosomes and is incorporated into the new nucleoli. The nonchromosomal PCN, after the breakdown of the nuclear membrane, distributes in the cytoplasmic region around the condensed chromosomes and diffuses into the cytoplasm during anaphase. Preliminary biochemical analysis by immunoblotting showed that the PCN consists of two main proteins with molecular masses of 36 kDa and 30 kDa.

Long term survival of radiotherapy for esophageal cancer: analysis of 1136 patients surviving for more than 5 years

One thousand one hundred and thirty-six patients surviving for more than five years after radiotherapy were studied. The important prognostic factors are: lesion less than 5 cm in length, lesion located in the upper-third segment and lesion that is radiosensitive. The radiation dose given to long term survivors varies greatly, i.e., 2700 to 9300 rad. Yet, for the sensitive type of lesion, doses lower than 5000 rad could also effect a cure. The delivery of an optimum dose determined by serial examinations during radiotherapy could improve the result of treatment. For local recurrent lesions, the value of a second course of radiation is extremely limited and surgery is the only means to offer a cure. For metastasis in the lymph nodes, radiation offers some hope of cure, although the long term outcome may not be satisfactory. For second primary cancer of the esophagus, aggressive radiation still gives encouraging results.