Shoji Wakasugi

Mitochondrial DNA-like sequences in the human nuclear genome. Characterization and implications in the evolution of mitochondrial DNA

Thirty-three phage clones carrying DNAs homologous to human mitochondrial DNA (mtDNA) were isolated from two independently constructed human gene libraries, and the region and extent of homology of mtDNA-like sequences carried by these clones were examined in hybridization experiments. Each phage clone contained DNA sequences homologous to various parts of the mtDNA and the extent of homology differed from clone to clone. From the efficiency of the library screening, it was estimated that human nuclear DNA contains at least several hundred copies of mtDNA-like fragments. Four clones carrying nuclear DNA sequences homologous to the mitochondrial Unidentified Reading Frame (URF) 4 and URF5 regions were chosen for further studies, and their structures were analyzed by DNA sequencing. Comparison of these mtDNA-like sequences with that of mtDNAs of several mammalian species revealed conservation of a part of the structures present in direct ancestral mtDNAs. The mtDNA fragments seem to have been continuously integrated into mammalian nuclear DNA during evolution.

Metastatic melanoma to the palatine tonsil with a favourable prognosis.

Metastasis to the oral cavity from cutaneous melanoma is rare: fewer than 30 cases of metastatic melanoma to the palatine tonsil have been reported. Tonsil metastasis is haematogenously disseminated and therefore usually has a poor prognosis. We present a case of metastatic melanoma to the palatine tonsil occurring 6½ years after removal of the primary cutaneous lesion. The patient has remained disease‐free for 18 months since the removal of skin and tonsil metastases. Immunohistopathologically, HLA class II and costimulatory factor B7‐2 molecules were concomitantly expressed on melanoma cells: we suggest that the patient was therefore able to develop antimelanoma T‐cell activation resulting in prevention of further metastasis, and thus a favourable prognosis.

Immunohistochemical characterization of the cellular infiltrate in localized scleroderma

Background  Localized scleroderma is a connective tissue disorder with hardening of the skin and fibrosis of the affected tissue as the most prominent features. The etiology of localized scleroderma is still unknown, but immunologic factors may play an important role in the pathogenesis. This study was performed to determine the immunohistochemical features of the cellular infiltrate in localized scleroderma.

Two cases of anti-epiligrin cicatricial pemphigoid with and without associated malignancy

Anti-epiligrin cicatricial pemphigoid (AECP) is a chronic, mucous membrane-dominated, subepithelial blistering disease characterized by circulating anti-basement membrane zone auto-antibodies to laminin 5. Recent studies have shown that people with AECP have an increased relative risk for malignant tumours. In this report we describe two patients with AECP. In both cases, indirect immunofluorescence demonstrated circulating IgG anti-basement membrane auto-antibodies that bound to the dermal side of 1M NaCl split normal skin. Immunoblotting using laminin 5 purified from keratinocyte extract as a substrate showed that the IgG antibodies of patient 1 reacted with the 140-kDa beta3 subunit of laminin 5 and IgG antibodies of patient 2 reacted with the 165-kDa and 145-kDa alpha3 subunits. Patient 1 had prostate carcinoma and his blistering was resistant to therapy. Patient 2 had no detectable malignancy and treatment with doxycycline was successful.

Role of serum amyloid P component for systemic amyloidosis in transgenic mice carrying human mutant transthyretin gene

The role of serum amyloid P component (SAP) for systemic amyloidosis in a transgenic mouse model for an autosomal dominant disease, familial amyloidotic polyneuropathy (FAP), was examined. For this purpose, two lines of transgenic mouse were produced by introducing the human mutant transthyretin (TTR) gene and the human SAP gene, respectively. Two lines of transgenic mice were mated to produce double transgenic mice carrying both human mutant TTR gene and human SAP gene. The serum concentration of human SAP in these transgenic mice was about 42 micrograms/ml and was about equal to that in human control serum. In case of single transgenic mice carrying human mutant TTR gene, amyloid deposition starts at around 6 months of age, and the amount of amyloid deposition increases gradually with age. Amyloid deposition is observed in many tissues including heart, kidney and thyroid gland, where amyloid deposition is commonly observed in FAP patients. In double transgenic mice, onset, progression and tissue distribution of amyloid deposition were the same as those in single transgenic mouse. These results clearly suggest that SAP is not important for the initiation and progression of amyloid deposition.

Giant malignant peripheral nerve sheath tumor of the scalp

Herein, we describe a rare case of giant malignant peripheral nerve sheath tumor of the head in a 38‐year‐old Japanese man. The tumor measured 210 mm at its largest diameter and was ulcerated, hemorrhagic, multilocular and non‐mobile. It should be noted that the patient stubbornly refused to see a doctor for a long time, resulting in the extreme growth of the tumor. We suspect a psychological basis for this behavior. Dermatohistopathological findings of the biopsy indicated ancient schwannoma and total excision was therefore performed. However, after 4 months, the patient developed multiple metastases and died. Post‐mortem skin biopsy revealed features of malignant peripheral nerve sheath tumor. We performed immunohistochemical studies on the primary and recurrent lesions and concluded that there was a difference in the expression of Ki67 and p16. We propose that the expressions of Ki67 and p16 should be checked for all lesions of peripheral nerve sheath tumor for distinguishing benign from malignant forms.

A novel nonsense mutation of the PEPD gene in a Japanese patient with prolidase deficiency

AbstractA nonsense mutation at amino acid residue 184 in the human peptidase D (PEPD) gene caused the production of a truncated polypeptide. Characterizing molecular defects in patients provides clues to elucidate the relationship between the phenotype and the genotype.

Clinical Phenotype of Bart's Syndrome Seen in a Family with Dominant Dystrophic Epidermolysis Bullosa

Background: Barts syndrome is one type of dominant dystrophic epidermolysis bullosa (EB). It is known that, in some familial cases of dominant dystrophic EB, the symptoms differ depending on the individual. We observed the way Barts syndrome affected four generations in the same family. The proband was a newborn boy who showed congenital localized absence of skin (CLAS) and bullae on the anterior aspects of both legs. Histologically, the bullae were located subepidermally. The CLAS and bullae disappeared within 4 months after birth, leaving scars. His father retained scarring and scaling from the knees down along the anterior aspect of the legs, and the nails of the toes were either lacking or deformed. His paternal grandmother and great‐grandmother also presented deformed nails of the toes, although they had not had CLAS or bullae on the legs at birth. The individuals in this family thus showed some heterogeneity depending on the sex: blistering and CLAS were seen on the legs soon after birth in the male family members, but the female members did not share this pattern of symptoms, suggesting that the expression of symptoms may differ depending on the sex of the affected individual.

PDGFB quantification is a useful tool in the diagnosis of dermatofibrosarcoma protuberans: a study of 10 cases

Background.  Genetic aberrations involving the platelet‐derived growth factor‐β (PDGFB) gene and the collagen type 1 α1 (COL1A1) gene have been implicated in the pathogenesis of dermatofibrosarcoma protuberans (DFSP), a slow‐growing and locally infiltrative dermal tumour.

A Potential Animal Model for Familial Amyloidotic Polyneuropathy Through Introduction of Human Mutant Transthyretin Gene Into Mice

Familial amyloidotic polyneuropathy (FAP) has been identified in a number of kindreds of the world. FAP is an autosomal dominant disorder characterized by extracellular deposition of fibrillar amyloid protein and by prominent peripheral nerve involvement (1–4). This protein is mainly composed of TTR with a substitution of methionine for valine at position 30 in the FAP type I, as reported in Japan, Sweden and Portugal (5–7). This amino acid substitution is thought to lead to amyloid deposition. The human TTR gene has been cloned and well characterized at the molecular level (8, 9). All the FAP patients so far examined carry one mutant gene (10, 11). However in patients with FAP, the age at onset varies from 20 to 45 years. In addition the clinical syndrome is variable even among kindreds with the same genetic defect. These data suggest involvement of factor(s) other than the single nucleotide mutation in the TTR gene. To elucidate this factor(s) and to examine the pathological process of amyloid deposition, we have produced transgenic mice by microinjecting the cloned human mutant TTR gene into fertilized eggs of C57BL/6 mice.