Cell cycle control and CDC28/Cdc2 homologue and related gene cloning of Cryptococcus neoformans]

In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G2 phase and cause accumulation of cells after DNA synthesis, but before commitment to budding. The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans.     

Gene therapy for gastrointestinal tract cancer: Prospects for combination treatment consisting of surgery and molecular surgery

Progress in understanding carcinogenesis has shown cancer to be a disease caused by gene abnormalities, and a variety of oncogenes and tumor suppressor genes have thus been identified. Advances in molecular biology have given us new tools for diagnosing, staging and predicting the outcome for cancer patients and gene therapy could therefore potentially revolutionize the treatment of gastrointestinal (GI) tract cancer. Progress has been made in several approaches related to genetic modification: (1) antisense oncogene and the restoration of tumor suppresor gene therapy; (2) suicide gene therapy; and (3) cancer immunotherapy. In situ in vivo gene transfer is a practical method of gene therapy for GI tract cancer. Although many hurdles need to be overcome to achieve effective gene transfer and targeting, our early results of in situ in vivo suicide gene therapy for canine gastric cancer are promising. The era of combined treatment consisting of surgery and molecular surgery for GI tract cancer is thus considered to soon be possible.     

Molecular cloning of a novel human papillomavirus (type 60) from a plantar cyst with characteristic pathological changes.

In a plantar cyst composed of the wall of the squamous cell layer and the horny inner substance in the lower dermis, we found characteristic pathological changes, such as cytoplasmic eosinophilic inclusions and vacuolated structure, and, immunohistochemically, the papillomavirus capsid antigen. The human papillomavirus (HPV) DNA cloned from the cyst showed no homology with other known prototypes of HPV (HPV 1 through HPV 59) by Southern blot analysis under stringent conditions and was named as HPV 60. HPV 60 DNA was found in three other cases of plantar cyst with the identical pathological changes, but not in a plantar cyst without such changes. The results suggest that HPV 60 has unique biological properties to induce a plantar cyst as a distinct type of cutaneous HPV.     

A Case of Pelvic Osteomyelitis

A patient presenting with osteomyelitis of the pelvis is described. In this case it was difficult to establish a correct diagnosis by use of scintigraphic scanning, in spite of clear roentgenographic evidence of osteomyelitis.     

Correlation between epidermal growth factor receptor concentration and the growth of human gastric cancer xenografts in nude mice.

Seven human gastric cancer xenografts with different concentrations of EGF receptor were established in nude mice. The expression of EGF receptor in the tumors was demonstrated by Western blotting with anti-EGF receptor antibody, binding assay with 125I-EGF and immunohistochemistry with anti-EGF receptor antibody. Western blotting revealed EGF receptor doublet bands at molecular masses of 150 KDa and 170 KDa in all of the samples. The concentration of 125I-EGF binding activity in the tumors ranged from 36.0 to 11,000 fmol/mg protein, with a mean of 345 fmol/mg protein. EGF receptor was also demonstrated immunohistochemically on the apical border of the glands and the cell membrane of the tumor cells. There seemed to be a close correlation between the concentration of 125I-EGF binding activity and the doubling time of these tumors in nude mice (gamma = -0.68). However, no definite correlation was observed between EGF ligand binding and histological features of intestinal type or diffuse type. The expression of EGF receptor appears to facilitate the growth of human gastric cancer xenografts in nude mice.     

Rare associations of dens invaginatus and mesiodens.

Dens invaginatus is a developmental variation resulting from an alteration in the normal growth pattern of the dental papilla. Synonyms of this disturbance include dens in dente, invaginated odontome, tooth inclusion, and dentoid in dente. Radiographically, it is observed as infolding of a radiopaque ribbon-like structure, with equal density as enamel, extending from the cingulum into the root canal and sometimes reaching the root apex, assigning the appearance of a small tooth within the coronal pulp cavity. This article presents 2 case reports. The first describes an 8-year-old girl with dens invaginatus in a mesiodens; the second report describes a 16-year-old boy presenting with 2 mesiodens, both associated with dens invaginatus.