Colorectal carcinogenesis is a multi-step process during which genetic and epigenetic events determine the transition from a normal cell to a malignant cell.
In the past decade, intensive research led to the identification of two types of colorectal cancers that are distinct by their carcinogenesis process. The first group, named LOH (Loss of Heterozygosity) type, is characterized by allelic losses of tumor suppressor genes. The second group, called MSI (Microsatellite Instability) type, is characterized by genetic instability at microsatellite loci. In addition, recent studies suggest the four different signaling pathways, Wnt/Wingless pathway, K-ras pathway, TGF-beta pathway and p53 pathway, could be implicated in tumor progression.
In this review we discuss the development of colorectal cancer on the basis of molecular biology and recent advances in research of the colorectal cancer.

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[Background] Although many patients complain of eye fatigue caused by accommodative spasm, there have been no reports of a good objective examination method to diagnose it. [Purpose] The spectral power of the high frequency component of the accommodative microfluctuation (spectral power of HFC) differs according to the constrictive degree of the accommodation. In this paper, we expatiated upon our previously reported analyzing processes of the spectral power of HFC, and we investigated the relationship between normal subjects and subjects with asthenopia. [Method] The accommodative microfluctuation were recorded when the subjects were looking at a stable target. The waves of the accommodative microfluctuation were analyzed by FFT. [Results] The spectral power of HFC for the distant target was 50-60 in the subjects with normal vision, but it was higher in the subjects with asthenopia. [Conclusion] Our results suggested that the ciliary muscle was also actively working in asthenopia caused by accommodative spasm even if the patient was looking at a distant target.

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Motor evoked potentials by magnetic stimulation is less invasive and causes no pain as opposed to high current electric stimulation. However, the distribution of the magnetic field generated by the round coil has not been fully studied. In this report, we mapped the extent of the magnetic induction flux density, and then the evoked potentials from the spinal cord were investigated by transcranial magnetic stimulation. We also examined the origin of the evoked potentials obtained by the magnetic stimulation. The following results were obtained. The magnetic induction flux density was at its maximum at the edge of the coil. The potentials consisted of a first negative wave and subsequent multiphasic waves. The first negative wave was similar to a response of the subcorticospinal tract in the lower brain stem, while the subsequent multiphasic waves were similar to those of the pyramidal tract. Although magnetic stimulation has certain advantages over electric stimulation, several problems remain to be solved for the monitoring of motor functions in the clinical settings.

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Thrombocytopenia due to immune mechanisms is rare and difficult to manage in elderly patients. We describe a case of an 89-year-old female with severe immune thrombocytopenia (ITP) who rapidly improved by pulse therapy with cyclophosphamide. She was admitted to our hospital because she had arthralgia in both sides of her femoral region since January 1999, aphthous stomatitis and ecchymosis of the leg since April 1999, and bloody phlegm in July 1999. On admission, her peripheral blood count revealed severe thrombocytopenia (0.1×10⁴/μl). Her megakaryocyte count from bone marrow was increased to 512/μl without abnormal cells. Systemic lupus erythematosus was suspected because of strong-positive protein in the urine in addition to the clinical and hematological findings described above, but she was negative for all the autoantibodies examined. Finally, she was diagnosed as having ITP on the basis of high platelet-associated immunoglobulin G in addition to hematological and physical findings and she was treated with prednisolone. It was difficult to maintain her platelet count with only prednisolone, but 600 mg of cyclophosphamide rapidly increased her platelet count in spite of tapering the prednisolone. In September 2000, her platelet count was kept within normal limits by administration of 15 mg/day of prednisolon. It is suggested that immunosuppressive therapy for ITP using high-dose cyclophosphamide is useful in elderly patients as well as in juvenile adult patients.

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