Specific interaction between the initiator protein (Rep) and origin of plasmid ColE2-P9

The replication initiator protein (Rep) of plasmid ColE2-P9 (ColE2) is multifunctional. We are interested in how Rep binds to the origin (Ori) to perform various functions. We used the wild type and variants of Rep to study the Rep-Ori interaction by both in vitro and in vivo approaches, including biochemical analyses of protein-DNA interactions and an in vivo replication assay. We identified three regions (I, II, and III) of Rep, located in the C-terminal half, and three corresponding binding sites (I, II, and III) in Ori which are important for Rep-Ori interaction. We showed that region I, containing a putative helix-turn-helix motif, is necessary and sufficient for specific Ori recognition, interacting with site I of the origin DNA from the major groove. Region II interacts with site II of the origin DNA, from the adjacent minor groove in the left half of Ori, and region III interacts with site III, next to the template sequence for primer synthesis, which is one and one-half turn apart from site I on the opposite surface of the origin DNA. A putative linker region located between the two DNA binding domains (regions II and III) was identified, which might provide Rep an extended conformation suitable for binding to the two separate sites in Ori. Based on the results presented in this paper, we propose a model for Rep-Ori interaction in which Rep binds to Ori as a monomer.

Immunohistochemical analysis of nuclear survivin expression in esophageal squamous cell carcinoma

Despite advances in the treatment of esophageal carcinoma, the prognosis for this disease remains poor. Therefore, it is important to obtain a better understanding of the molecular basis of esophageal carcinogenesis. The purpose of this study was to clarify the roles of survivin in esophageal squamous cell carcinoma (ESCC). One hundred 22 ESCC surgical specimens resected from 1989 to 1999 were examined. Survivin expression was assessed by immunohistochemistry. Tumor cells were considered survivin-positive if the immunoreactivity was confined to the nucleus, and a scoring method was applied. Survivin-positive immunostaining was detected in 68 patients (56%). There was a significant association between survivin expression and pN (P = 0.0472). Moreover, the overall survival rate was worse in patients with survivin-positive tumors than in patients with survivin-negative tumors (P = 0.0189). The overexpression of survivin was associated with the overall survival rate and poor prognosis in patients with ESCC. Survivin may be targeted during cancer therapy because of its selective expression in malignant tissue.

Advanced oesophageal carcinoma in an 84-year-old treated with chemoradiotherapy

We present a case of advanced oesophageal cancer with cardiac invasion in an 84-year-old male presenting with dysphagia and general malaise. Histological analysis of an endoscopic biopsy specimen revealed a poorly differentiated squamous cell carcinoma. Computed tomography indicated a thickened oesophageal wall that was compressing the left atrium, suggesting invasion of the heart, and oesophagography revealed a polypoid lesion 9 cm in length. No distant metastases were seen on computed tomography. The patient was given chemotherapy with 10 mg/m2 cisplatin on days 1 and 4 every week for 5 weeks and concurrent radiotherapy at a dose of 2 Gy five times per week (total dose 52 Gy). After 4 weeks, the mass was no longer visible on oesophagography or endoscopic examination. The patient was free of recurrence and metastases for 4.5 years. In conclusion, chemoradiotherapy may be curative in elderly patients with unresectable oesophageal carcinoma.

Management and algorithm for focal nodular hyperplasia of the liver in children

PURPOSE

The aim of this study was to determine an appropriate management plan for childhood and adolescent FNH, in particular to establish an algorithm for preoperative diagnosis and treatment.

PATIENTS AND METHODS

Between 1985 and 2003, 4 children with FNH were diagnosed. Of these 4 patients, 3 (Group A) underwent tumor resection, and 1 (Group B) was treated by conservative management. Clinical data, pathological findings and follow-up were evaluated retrospectively.

RESULTS

The 3 patients in Group A were symptomatic, while the 1 patient in Group B was asymptomatic. In 3 of 4 patients, a homogeneous tumor with a central stellate area was noted on abdominal ultrasonography, CT scan and MR imaging. In case 2, SPIO-enhanced MR imaging was useful for differentiating FNH from hepatocellular carcinoma. Though percutaneous needle biopsy was performed in case 3, a pathologically definitive diagnosis was impossible. An open biopsy was performed in case 4 and FNH was diagnosed. In case 4 treated by conservative management, the tumor size did not change during the 7 years after the diagnosis of FNH.

CONCLUSION

FNH is usually treated conservatively because of the good evolutionary outcome of the lesion. Surgery is indicated in cases of complications, compressed adjacent organs, lesion progression, or for symptomatic patients. We advocate the use of less invasive SPIO-enhanced MR imaging instead of open biopsy when the diagnosis of focal liver lesions is not clear after contrast-enhanced CT scan and non-enhanced MR imaging.

Alteration of T-cell receptor repertoires during thymic T-cell development

The majority of thymocytes die in the thymus, whereas small populations of T cells that are able to specifically recognize an antigen are considered to survive. Although the thymic selection is thought to have a profound effect on T-cell receptor (TCR) repertoire, little is known how TCR repertoire is formed during the thymocyte developmental process. We examined TCRalpha- and beta-chain variable regions (TCRAV and TCRBV) repertoire in thymic T-cell subpopulations from mice bearing different major histocompatibility (MHC) haplotypes. In Balb/c mice, but not C57BL/6, remarkable alterations of the TCR repertoire were observed in mature T-cell subpopulations as previously reported. In contrast, there were no significant differences of TCRBV repertoire between DN3 (CD25(+)CD44(-)) and DN4 (CD25(-)CD44(-)), and between DN4 and DP. These results suggest that (1) TCR repertoire of mature T cells was formed mainly under the influence of endogenous superantigens, while MHC haplotypes played the least role; (2) the 'beta-selection' process during immature stages had little impact on TCRBV repertoire formation; and (3) TCR repertoire in immature T-cell subpopulations was extremely similar between different strains of mice. We thus consider that pre-selection TCR repertoire in immature T cells could be determined by some genetic factors conserved among different strains.

Nasal natural killer/T-cell lymphoma and its association with type "i"/XhoI loss strain Epstein-Barr virus in Chile

BACKGROUND

Nasal T/natural killer (NK)-cell lymphoma is an aggressive type of non-Hodking's lymphoma associated with Epstein-Barr virus (EBV) and striking geographical variations worldwide.

AIM

To characterise nasal NK/T-cell lymphoma associated with genotypes of EBV in Chile, a Latin American country, where multiple strains of EBV, including two new recombinant strains, in healthy individuals were recently found.

METHODS

Cases with diagnosis of primary nasal lymphoma were selected for histological and immunohistochemical analysis (CD3, CD3e, CD4, CD8, CD79a, CD56, CD57 and TIA-1) and in-situ hybridisation, serology and genotyping analysis for EBV.

RESULTS

Out of 22 cases, 9 (41%) cases fulfilled the World Health Organization criteria for nasal NK/T-cell lymphoma; of these 7 (78%) cases were positive for EBV. Genotyping analysis revealed 6 cases of type 1 EBV and wildtype F at the BamHI-F region, 4 cases type "i" EBV at the BamHI-W1/I1 region; XhoI wild type was found in 2 and XhoI loss in 4 cases, respectively. Cosegregation analysis of the BamHI-W1/I1 region and XhoI restriction site showed the new recombinant strain type "i"/XhoI loss in 3 cases and type "i"/XhoI wild-type strain in 1 case. Most patients were treated with combined anthracycline-containing regimens. Half of the cases attained complete remission.

CONCLUSION

Although nasal NK/T-cell lymphomas from Chile share similar clinicopathological features, high association with EBV and unfavourable prognosis with those described elsewhere, genotype analysis shows that the new recombinant type "i"/XhoI loss strain might contribute to explain the intermediate incidence of nasal NK/T-cell lymphomas in Latin America.

[Small peripheral lung cancer incidentally detected by massive hemoptysis]

A 47-year-old man was admitted to our hospital for treatment of massive hemoptysis. He was intubated and underwent bronchial arterial embolization because of this deteriorating respiratory state and uncontrollable hemoptysis. Computed tomography (CT) of the chest showed a 1-cm nodular shadow in the peripheral apical lobe (S1) of the right lung. He underwent right upper lobectomy for the purpose of preventing re-hemorrhage as well as making the definitive diagnosis of nodular shadow in S1 of the right lung. Intraoperative pathological examination revealed the nodule as adenocarcinoma, and mediastinal lymphadenectomy was added to the right upper lobectomy. The patient recovered uneventfully, and there has been no sign of recurrence for 15 months after the operation.

Concurrent infiltration by CD8+ T cells and CD4+ T cells is a favourable prognostic factor in non-small-cell lung carcinoma

The purpose of this study was to clarify the relationship between the number of tumour-infiltrating T lymphocytes and the clinicopathological features and clinical outcome in patients with non-small-cell lung cancer (NSCLC). Tissue specimens from 109 patients who underwent surgical resection for NSCLC were immunohistochemically analysed for CD4 and CD8 expression. Patients were classified into two groups according to whether their tumours exhibited a ‘high’ or ‘low’ level of CD8⁺ or CD4⁺ lymphocyte infiltration. Although the level of infiltration by CD8⁺ T cells alone had no prognostic significance, the survival rate for patients with both ‘high’ CD8⁺ and ‘high’ CD4⁺ T-cell infiltration was significantly higher than that for the other groups (log-rank test, P=0.006). Multivariate analysis indicated that concomitant high CD8⁺ and high CD4⁺ T-cell infiltration was an independent favourable prognostic factor (P=0.0092). In conclusion, the presence of high levels of both CD8⁺ T cells and CD4⁺ T cells is a significant indicator of a better prognosis for patients with NSCLC, and cooperation between these cell populations may allow a significantly more potent antitumour response than either population alone.

Histological differentiation between prenatally diagnosed choledochal cyst and type I cystic biliary atresia using liver biopsy specimens

Because it is difficult to distinguish preoperatively between prenatally diagnosed choledochal cyst (CC) and type I cystic biliary atresia (BA) by ultrasound scanning or magnetic resonance imaging (MRI), some modality of discrimination for the 2 entities is required. The aim of this study was to investigate the histological differences between prenatally diagnosed CC and type I cystic BA using liver biopsy specimens. Four children with prenatally diagnosed CC and two children with prenatally diagnosed type I cystic BA were identified by fetal ultrasonography between 1985 and 2003. The control group included two children who were operated on at an earlier period due to postnatally diagnosed BA. Liver wedge biopsy in the right lobe was performed at the time of the radical operation. Histological findings of the H & E-stained liver biopsy specimens were classified into 4 grades (Grade 0, no abnormality; Grade 1, ductular proliferation without bridging fibrosis; Grade 2, ductular proliferation with bridging fibrosis; and Grade 3, liver cirrhosis). The CC group consisted of one case of Grade 0 and three cases of Grade 1. The type I cystic BA group consisted of one case each of Grade 2 and Grade 3. In the control group, both cases were Grade 2. The authors suggest that exploratory laparotomy might be avoided and, instead, histologic examination using liver biopsy specimens can be a reliable test for the differential diagnosis of CC and type I cystic BA in prenatally diagnosed neonates.

Management of childhood and adolescent thyroid carcinoma: long-term follow-up and clinical characteristics

AIM

This analysis was performed to evaluate clinical factors such as local tumor control, control of distant metastasis, survival, and complications in children and adolescents with thyroid carcinoma.

MATERIALS AND METHODS

From 1960 to 2003, 21 children and adolescents (16 girls and 5 boys, aged 4 to 15 years) were treated for thyroid carcinoma in our departments. Clinical data, operative findings, pathological findings, operative procedures, intra- and postoperative complications and follow-up were evaluated. Follow-up of patients ranged from 3 to 42 years (median, 20 years).

RESULTS

Papillary carcinoma was found in 20 patients (95%) and follicular carcinoma in one patient. Cervical lymph node metastases were found in 12 out of 21 patients (57.1%) when thyroid carcinoma was diagnosed, and 5 patients (23.8%) had pulmonary metastasis. In patients with pulmonary metastasis, total thyroidectomy and bilateral radical lymph node resection was performed in 3 patients, lobectomy of the thyroid and radical lymph node resection in one patient, and partial thyroidectomy in one patient. All three patients who underwent total thyroidectomy are still alive. Internal irradiation by 131I and thyroid hormone replacement therapy was administered to 2 of 3 patients with pulmonary metastasis.

CONCLUSION

Despite metastasis in the lymph nodes and even the lungs, the prognosis for patients with papillary carcinoma is good. Total thyroidectomy and positive 131I therapy are recommended for childhood and adolescent thyroid carcinoma with pulmonary metastasis.

Limited VH gene usage in B-cell clones established with nurse-like cells from patients with rheumatoid arthritis

OBJECTIVES

Nurse-like stromal cells (NLC) in synovia and bone marrow of patients with rheumatoid arthritis (RA) can support pseudoemperipolesis, protect from apoptosis and enhance immunoglobulin production of peripheral blood B cells isolated from healthy individuals, suggesting the profound contribution of hyperactivation of B cells in RA. In the course of establishing RA-NLC from RA patients, we observed the growth of B cells in the presence of RA-NLC.

METHODS

We cloned B cells from the synovium or bone marrow of RA patients using the limiting dilution technique. For established clones, nucleotide sequences of immunoglobulin and surface antigens were investigated. To investigate the dependence of these clones on NLC, differences in the proliferation and the amount of immunoglobulin produced in the presence or absence of NLC were compared. Immunocytochemical staining of various cells was performed using the antibody these clones produced.

RESULTS

Nine B-cell clones established from RA patients showed RA-NLC-dependent growth. These B-cell clones expressed CD19, CD20, CD38, CD39 and CD40, suggesting that the cloned cells were mature and activated. All clones secreted immunoglobulins in culture media, which were specific for intracellular components of various cell lines, including RA-NLC. Interestingly, we found limited usage of immunoglobulin heavy-chain variable regions (VH) among B-cell clones from RA patients. These repertoires were reported to be detected preferentially in fetal livers.

CONCLUSION

The present study provides a novel insight into the involvement of RA-NLC in the immunopathogenesis of RA via an autoreactive B cell development and/or activation mechanism.

WT1 expression level and clinical factors in multiple myeloma

Although Wilm's Tuomor gene (WT1) was first identified as a tumor suppressor gene for Wilm's tumor, WT1 overexpression has been detected in different malignant cell types including leukemia. Increased expression of WT1 in acute leukemia is potentially used as a marker of minimal residual disease. However, the significance of the gene for multiple myeloma is still not clear. To determine the clinical relevance of WT1 expression in multiple myeloma, we examined the association of clinical parameters and WT1 expression in bone marrow for 17 newly diagnosed multiple myeloma patients. WT1 was assessed by real-time quantitative polymerase chain reaction (RQ-PCR) and calculated standardized WT1 expression level per 100 plasma cells in the bone marrow specimen as "corrected WT1". The expression of standardized WT1 and corrected WT1 in myeloma was 59 to 1,600 copies/microg RNA and 0.05 to 406.3 copies/microg RNA/100 plasma cells, respectively, lower than in leukemia. WT1 transcripts increased when clinical factors worsen, including the stage, amount of M protein, Hb, platelet count, blood urea nitrogen (BUN), creatinine, serum alkaline phosphatase (ALP), calcium, beta2-microglobulin, thymidine kinase activity (TK), and C-reactive protein (CRP). In conclusion, the expression level of WT1 could be an additional marker to the standard parameters considered in risk assessment for multiple myeloma.

Ordering on multiple lengthscales in a series of side group liquid crystal block copolymers containing a cholesteryl-based mesogen

Hierarchical ordering in a side group liquid crystal block copolymer is investigated by differential scanning calorimetry, polarized optical microscopy, small-angle X-ray and neutron scattering (SAXS and SANS) and transmission electron microscopy (TEM). A series of block copolymers with a range of compositions was prepared by atom transfer radical polymerization, comprising a polystyrene block and a poly(methyl methacrylate) block bearing chiral cholesteryl mesogens. Smectic ordering is observed as well as microphase separation of the block copolymer. Lamellar structures were observed for far larger volume fractions than for coil-coil copolymers (up to a volume fraction of liquid crystal block, = 0.8). A sample with = 0.86 exhibited a hexagonal-packed cylinder morphology, as confirmed by SAXS and TEM. The matrix comprised the liquid crystal block, with the mesogens forming smectic layers. For the liquid crystal homopolymer and samples with high , a smectic-smectic phase transition was observed below the clearing point. At low temperature, the smectic phase comprises coexisting domains with monolayer S coexisting with interdigitated S domains. At high temperature a S phase is observed. This is the only structure observed for samples with lower . These unprecedented results point to the influence of block copolymer microphase separation on the smectic ordering.

Analysis of the antigen recognition sites of anti-methamphetamine monoclonal antibodies (II): unique feature of MA-3 antibody

A monoclonal antibody against methamphetamine (MA-3 mAb) was found to be strongly bound to ephedrine. This feature was quite different from that of other fourteen mAbs against MA. Analyses of cDNA sequence and steric conformation by molecular modeling revealed that one hydrophilic pocket was generated in the heavy chain of MA-3 mAb involving CDRH-1 and CDRH-2. Asn33, Asn35, Asn50 and Asp52 were the main components of the unique pocket capable of binding to the hydroxyl group of ephedrine.

Epstein-barr virus detection in tumors of upper gastrointestinal tract. An in situ hybridization study in Pakistan

To examine the potential role of Epstein-Barr virus (EBV) in the carcinogenesis of upper gastrointestinal tract, we conducted an in situ hybridization assay for EBV-encoded small RNA (EBER) expression in the tumors of 56 oral and 50 esophageal squamous cell carcinoma (SCC) cases, and 52 stomach adenocarcinoma cases diagnosed in the King Edward Medical College and Allama Iqbal Medical College Lahore, Pakistan between 1996-2002. There were no malignancies with positive EBER expression in oral and esophageal SCC. Only one out of the 52 gastric adenocarcinoma cases (1.9%) was positive for EBER expression, and this frequency was relatively low as compared to cases reported worldwide. The case was a 42 year-old male patient and histologically classified as moderately differentiated tubular adenocarcinoma. In conclusion, the frequency of EBV-associated gastric carcinoma was relatively low in Pakistan. The present study could not confirm the involvement of EBV in the carcinogenesis of oral and esophageal SCC.

Root fracture in immature anterior teeth followed for 15 years

We report a case of injury to an immature tooth, observed over a period of 15 years. In 1987, a 9-year-old boy fell down in a schoolyard. The right central incisor demonstrated palato-version and radiographic observations revealed that the roots of both central incisors were incomplete. Further, a root fracture in the apical region of the central incisors was observed. During the first treatment visit, the right central incisor was repositioned and both teeth splinted. After confirming that the line of fracture was aligned, the fixation was continued for 2 months. The teeth were examined periodically for the next 15 years. Both teeth had favorable outcomes with continued root development of both the apical and coronal segments with good apposition of the fracture lines.

Bleeding disorder as the first symptom of biliary atresia

Biliary atresia (BA) is occasionally diagnosed in infants whose first symptom is a bleeding disorder, such as intracranial bleeding, nasal bleeding or gastrointestinal bleeding. The authors describe 3 cases in which a bleeding disorder was the first symptom of BA. The presenting symptom was intracranial bleeding in a male on day 55 after birth, nasal bleeding in a female at 65 days, and gastrointestinal bleeding in a female at 25 days. Coagulation studies revealed a vitamin K deficiency in all patients. After the administration of vitamin K, the results of coagulation tests normalized and the bleeding tendency of the infants ceased. Subsequently, BA was suspected to be the cause of these bleeding disorders based on imaging findings. BA should therefore be considered in all infants with sudden onset of a tendency to bleed.