Micronodular thymoma with lymphoid stroma diagnosed 10 years after the first operation: a case report

INTRODUCTION

Micronodular thymoma with lymphoid stroma is a rare subtype of thymoma. Here we report a case of micronodular thymoma with lymphoid stroma that was completely resected after incomplete resection 10 years earlier.

CASE PRESENTATION

A 70-year-old Japanese woman who had undergone resection for a thymic cyst 10 years earlier was found to have a solid nodule with a multilocular lesion at the site of the previous operation. We suspected that the tumor was a malignant tumor and performed trans-sternal radical thymectomy and diagnosed the lesion as micronodular thymoma with lymphoid stroma pathologically. When we reassessed the thymic cyst that had been resected 10 years earlier, a few lesions of micronodular thymoma with lymphoid stroma were found in the cyst wall. Based on these findings, we concluded that only the cystic component of micronodular thymoma with lymphoid stroma had been removed, and that the residual lesion grew locally over the next 10 years before being completely resected by reoperation.

CONCLUSION

We experienced an unusual case of micronodular thymoma with lymphoid stroma, which is a rare subtype of thymoma. Greater care should be taken to exclude a thymoma with a cystic lesion, even if a thymic cyst is strongly suspected on computed tomography and magnetic resonance imaging.

Life-threatening complications after pulmonary resection for lung cancer in patients on chronic hemodialysis

PURPOSE

The morbidity and mortality associated with lung cancer surgery in patients on chronic hemodialysis (CHD) is high; however, the relationship between the severity of postoperative complications and clinicopathological features is unclear.

METHODS

Among 1214 consecutive patients who underwent pulmonary resection for primary lung cancer in our institute between 2004 and 2015, we identified 21 patients on CHD, who were the subjects of this study. Life-threatening postoperative complications were defined as grade 4 and 5 per the Clavien-Dindo classification.

RESULTS

Fourteen (67%) of these 21 patients suffered postoperative complications, which were life threatening in 5. There was a higher frequency of interstitial pneumonia (IP) in the patients with life-threatening postoperative complications than in those with complications that were not life threatening (p = 0.032). The rates of acute exacerbation and 90-day mortality in the patients with IP were 50% and 75%, respectively. The overall survival (OS) rate of the patients with life-threatening postoperative complications was significantly lower than that of those with complications that were not life threatening (1- and 3-year OS rates: 40% and 0% vs. 80% and 57%, respectively, p = 0.001).

CONCLUSIONS

Postoperative mortality and morbidity were high in patients on CHD who underwent pulmonary resection, especially if they had coexisting IP. Although IP is not a contraindication to pulmonary resection, the surgical strategy for CHD patients with IP should be considered carefully.

Effects of secondary EGFR mutations on resistance against upfront osimertinib in cells with EGFR-activating mutations in vitro

OBJECTIVES

Non-small cell lung cancers (NSCLCs) that harbor activating mutations for epidermal growth factor receptor (EGFR) show remarkable initial response to EGFR-tyrosine kinase inhibitors (TKIs), but inevitably acquire resistance, half of which are due to a T790 M secondary mutation when first-generation (1 G) or 2 G EGFR-TKIs are used. Osimertinib, a 3 G EGFR-TKI, is a standard of care in this situation, but eventually also evokes resistance, reportedly due to some tertiary EGFR mutations. However, the FLAURA trial showed the superiority of osimertinib over 1 G EGFR-TKIs in treatment-naïve patients, thus providing an option of first-line osimertinib treatment. Resistance in this setting is also inevitable, but its mechanism is unclear. We investigated whether resistance mutations that emerged with T790 M were responsible for the osimertinib resistance in the first-line setting; i.e. without T790 M, and if so, what treatment option was available.

MATERIALS AND METHODS

We used literature search to identify EGFR mutations at codons L718, G724, L792, G796, and C797 as mechanisms of osimertinib resistance in the presence of T790 M. These mutations were introduced into Ba/F3 cells in cis with activating EGFR mutations but not with T790 M; inhibitory effects of five EGFR-TKIs were evaluated.

RESULTS

Only C797S conferred significant resistance against osimertinib when exon 19 deletion was the activating mutation. However, co-existence of L858R with C797S, C797 G, L718Q, or L718 V mutations all conferred resistance to osimertinib. Erlotinib showed the greatest activity for C797S-mediated resistance. However, 2 G EGFR-TKIs (afatinib or dacomitinib) were effective for other resistance mutations.

CONCLUSION

After first-line osimertinib failure, 1 G or 2 G EGFR-TKIs are effective, depending on combinations of secondary and activating mutations.

Activity of a novel HER2 inhibitor, poziotinib, for HER2 exon 20 mutations in lung cancer and mechanism of acquired resistance: An in vitro study

OBJECTIVES

Oncogenic HER2 mutations are present in 2-4% of lung adenocarcinomas, but the relevant clinical trials are unsatisfactory. The novel HER2 inhibitor poziotinib was recently developed and clinical trials are ongoing. We compared poziotinib with nine tyrosine kinase inhibitors (TKIs), and derived poziotinib-resistant clones to investigate the resistant mechanism.

MATERIALS AND METHODS

We introduced three common HER2 mutations A775_G776insYVMA (YVMA), G776delinsVC (VC) and P780_Y781insGSP (GSP), which account for 94% of HER2 exon 20 insertions in the literature, into Ba/F3 cells. We then compared the activity of poziotinib with that of nine TKIs (erlotinib, afatinib, dacomitinib, neratinib, osimertinib, AZ5104, pyrotinib, lapatinib, and irbinitinib), determined the 90% inhibitory concentration (IC₉₀) through a growth inhibition assay, and defined a sensitivity index (SI) as IC₉₀ divided by the trough concentration at the recommended dose as a surrogate for drug activity in humans. We also generated resistant clones by exposure to poziotinib in the presence of N-ethyl-N-nitrosourea, and HER2 secondary mutations that might serve as a resistance mechanism were searched.

RESULTS

YVMA showed resistance to all tested drugs except neratinib, poziotinib and pyrotinib. Poziotinib was the only drug with an SI less than 10 for YVMA, the most common HER2 exon 20 insertion. We established 62 poziotinib-resistant clones, and among these, only C805S of HER2, which is homologous to C797S of the EGFR, was identified as a secondary mutation in 19 clones. We also revealed that heat shock protein (HSP) 90 inhibitors show potent anti-growth activity to the C805S secondary mutant clone.

CONCLUSIONS

Poziotinib showed the most potent activity against HER2 exon 20 mutations. We identified the secondary C805S at the covalent binding site of HER2 to poziotinib as a potential mechanism of acquired resistance. HSP90 inhibitors might be a therapeutic strategy for the C805S secondary mutation.

A new approach to left sleeve pneumonectomy: complete VATS left pneumonectomy followed by right thoracotomy for carinal resection and reconstruction

Background

Left sleeve pneumonectomy is a challenging operation that requires individualized approaches. Here, we present a new minimally invasive combined thoracoscopic approach.

Case presentation

A 61-year-old woman was diagnosed with tracheobronchial adenoid cystic carcinoma. The tumor originated from the left main stem bronchus, and tumor with carinal involvement was observed. We judged that complete resection would be possible via left sleeve pneumonectomy. However, because tumor involvement with the esophagus and descending aorta was suspected, evaluation of resectability in advance was necessary. After confirmation via examination thoracoscopy of no involvement with the surrounding organs, complete VATS left pneumonectomy was performed and followed by right thoracotomy for carinal resection and reconstruction.

Conclusions

When thoracoscopic surgery becomes mainstream, this minimally invasive combined thoracoscopic approach might be an optimal option for patients who require left sleeve pneumonectomy.

EGFR T790M and C797S Mutations as Mechanisms of Acquired Resistance to Dacomitinib

INTRODUCTION

Dacomitinib was superior to gefitinib in terms of progression-free survival in patients with EGFR-mutant lung cancer in a recent ARCHER 1050 trial. However, despite a marked initial response, lung cancers eventually acquire resistance to these inhibitors. This study aimed to elucidate the mechanisms of acquired resistance to dacomitinib in vitro.

METHODS

Dacomitinib-resistant clones were established by exposure to fixed concentrations of dacomitinib by using N-ethyl-N-nitrosourea (ENU) mutagenesis or by chronic exposure to increasing concentrations of dacomitinib without ENU. EGFR secondary mutations were analyzed by Sanger sequencing. Time to resistance in each clone was compared according to the mutational status. EGFR Del19, L858R, and G719A mutations were introduced into Ba/F3 cells by using retroviral vectors.

RESULTS

Chronic exposure to dacomitinib without ENU induced T790M in Ba/F3 cells expressing Del19. ENU mutagenesis resulted in 171 dacomitinib-resistant clones. Among these clones, 90% acquired T790M. However, C797S occurred in 11% of L858R-mutant clones (four of 35) and in 24% of G719A-mutant clones (12 of 38) established by using low-dose dacomitinib. Time to resistance was not significantly different between T790M- and C797S-mutant clones in both of L858R clones (p = 0.93) and G719A clones (p = 0.86). Cells expressing Del19 that acquired T790M were sensitive to osimertinib, whereas cells with L858R plus C797S mutations were sensitive to gefitinib or erlotinib.

CONCLUSIONS

These in vitro data demonstrate that dacomitinib can directly induce T790M or C797S secondary mutations. Our data suggest the importance of analyzing these secondary mutations because appropriate selection of EGFR inhibitors could overcome acquired resistance to dacomitinib in a subset of lung cancers.

[A Case of Resected Superior Sulcus Tumor with Pathological Complete Response after Trimodality Therapy]

The current case was 73-year-oldwoman. She was referredto our hospital for an abnormal shadow of chest X-ray in the upper right lung field. Chest CT showed 3.5 cm of tumor located at the apex of right lobe with invasion of the chest wall. The tumor was diagnosed as squamous cell carcinoma using CT guided needle biopsy(superior sulcus tumor, clinical T3N0M0, Stage II B). The neoadjuvant therapy, 4 courses of chemotherapy(CBDCA plus PTX)andconcurrent radiotherapy(45 Gy/25 Fr)was performed. Chest CT revealed that tumor size was decreased to 2.3 cm in a diameter, and therapeutic effect was decided as partial response(34%). Upper right lobectomy combinedwith the chest wall(1th to 3th ribs)andmed iastinal lymph node dissection were performed. The pathological specimens showed no residual cancer cells(Ef3, pathological complete response[pCR]). She discharged without complications at 10 days after surgery. It is important to collect cases which obtainedpCR for development of more effective preoperative therapy.

Clinical significance of tumor cavitation in surgically resected early-stage primary lung cancer

OBJECTIVES

The prognostic impact of tumor cavitation is unclear in patients with early-stage primary lung cancer. The aim of the present study was to examine the clinicopathological features and prognoses of patients with pathological stage I-IIA (p-stage I-IIA) primary lung cancers harboring tumor cavitation. This study was conducted according to the eighth edition of the TNM classification for lung cancer.

MATERIALS AND METHODS

We examined 602 patients with p-stage I-IIA primary lung cancer out of 890 patients who underwent pulmonary resection from January 2007 through March 2014 and searched for the presence of tumor cavitation, which is defined as the presence of air space within the primary tumor.

RESULTS

A total of 59 out of the 602 patients had tumor cavitation (10%). Compared with patients without tumor cavitation, those with tumor cavitation had a significantly higher frequency of the following characteristics: high serum carcinoembryonic antigen (CEA) level (≥5ng/ml, p=0.027), interstitial pneumonia (p=0.0001), high SUVmax value on FDG-PET scan (≥4.2, p=0.023), tumors located in the lower lobe (p=0.024), large tumor size (>3cm, p=0.002), vascular invasion (66% vs 17%, p<0.0001) and non-adenocarcinoma histology (p=0.025). The overall survival period of patients with tumor cavitation was significantly shorter than that of patients without tumor cavitation (log-rank test: p<0.0001, 5-year OS rate: 56% vs 81%). Tumor cavitation was found to be an independent and significant factor associated with poor prognosis in the multivariate analysis (hazard ratio: 1.76, 95% confidence interval: 1.02-3.10, p=0.042).

CONCLUSIONS

Tumor cavitation is an independent factor for poor prognosis in patients with resected p-stage I-IIA primary lung cancer. Based on our analyses, patients with tumor cavitation should be regarded as a separate cohort that requires more intensive follow-up.

Controlling joint instability delays the degeneration of articular cartilage in a rat model

OBJECTIVE

Joint instability induced by anterior cruciate ligament (ACL) transection is commonly considered as a predisposing factor for osteoarthritis (OA) of the knee; however, the influence of re-stabilization on the protection of articular cartilage is unclear. The aim of this study was to evaluate the effect of joint re-stabilization on articular cartilage using an instability and re-stabilization ACL transection model.

DESIGN

To induce different models of joint instability, our laboratory created a controlled abnormal joint movement (CAJM) group and an anterior cruciate ligament transection group (ACL-T). Seventy-five Wistar male rats were randomly assigned to the CAJM (n = 30), ACL-T (n = 30), or no treatment (INTACT) group (n = 15). Cartilage changes were assessed with soft X-ray analysis, histological and immunohistochemistry analysis, and real-time polymerase chain reaction (PCR) analysis at 2, 4, and 12 weeks.

RESULTS

Joint instability, as indicated by the difference in anterior displacement between the CAJM and ACL-T groups (P < 0.001), and cartilage degeneration, as evaluated according to the Osteoarthritis Research Society International (OARSI) score, were significantly higher in the ACL-T group than the CAJM group at 12 weeks (P < 0.001). Moreover, joint re-stabilization maintained cartilage structure (thickness [P < 0.001], surface roughness [P < 0.001], and glycosaminoglycan stainability [P < 0.001]) and suppressed tumor necrosis factor-alpha (TNF-α) and caspase-3 at 4 weeks after surgery.

CONCLUSION

Re-stabilization of joint instability may suppress inflammatory cytokines, thereby delaying the progression of OA. Joint instability is a substantial contributor to cartilage degeneration.

[A Patient with Lung Adenocarcinoma, Lymphangitis Carcinomatosa, and Multiple Bone Metastases Who Achieved Long-Term Survival after Successful Treatment with Carboplatin, Paclitaxel, and Bevacizumab]

BACKGROUND

Lymphangitis carcinomatosa of the lung is intractable and associated with a poor prognosis.

CASE

A 53-year-old woman was admitted to our hospital due to an uncomfortable feeling on deep inspiration. She was diagnosed with left lung adenocarcinoma with lymphangitis carcinomatosa and bone metastases to the frontal bone of the skull and thoracic vertebrae. The lung carcinoma was positive for an EGFR mutation. Because the patient's performance status (PS) was 0, carboplatin plus paclitaxel plus bevacizumab therapy was initiated and she received zoledronic acid and concurrent radiation therapy of 40 Gy for the metastasis to the thoracic vertebrae. After 2 courses of treatment, the respiratory symptoms had improved. After 6 courses of treatment, a chest CT indicated that the lymphangitis carcinomatosa had disappeared. The serum CEA level, which was 126.2 ng/mL (normal<5.0) before treatment, reduced to 5.0 ng/mL. She was administered 10 courses of bevacizumab as a maintenance therapy; however, the CEA level rose again to 11.7 ng/mL, the lung tumor volume increased, and the metastasis of the frontal bone deteriorated. As second-line chemotherapy, EGFR-TKI was started. However, after 11 months, because of grade 4 liver dysfunction, EGFR-TKI was stopped. She then received fourth-line chemotherapy in our outpatient hospital. This patient has survived 52 months since the initial diagnosis.

CONCLUSION

Chemotherapy including bevacizumab facilitated long-term survival (52 months) of a patient with lung adenocarcinoma accompanied by lymphangitis carcinomatosa and multiple bone metastases.

[A case of lymphoepithelioma-like carcinoma of the bladder]

Lymphoepithelioma-like carcinoma (LELC) of the bladder is very rare and only a few cases have been reported so far. Here, we report a case of LELC of the bladder with distant metastasis. A 73-year-old man presented with macroscopic hematuria and miction pain. Cystoscopy revealed non-papillary tumor and tissue biopsy was performed. Histopathological examination showed pure type of LELC in the bladder. Fludeoxyglucose positron emission tomography revealed lymph node metastasis. The tumor progressed rapidly and the patient died 4 months later. Although the prognosis of pure type of LELC has been reported to be good, our case indicates that the prognosis of pure type with distant metastasis may be poor.

Improvement of diabetic or obese patients' erythrocyte deformability by the program of the brain-oriented obesity control system (BOOCS)

Diabetes is characterized by absolute or relative insulin deficiency complicated with microangiopathy, whereas obesity stems from insulin resistance. A psychosomatic approach to obesity and diabetes has been highlighted, including the brain-oriented obesity control system (BOOCS). Impaired deformability of erythrocytes in obese or diabetic patients is closely linked to disturbed microcirculation, and improvement of abnormal erythrocyte rheology is a prerequisite for the prevention and treatment of microangiopathy. Therefore, erythrocyte filterability, whole cell deformability defined as flow rate of erythrocyte suspension relative to that of saline, was assessed by the nickel-mesh-filtration technique. Subjects included healthy controls (group A, n = 14), diabetic, non-obese participants (group B, n = 29), and non-diabetic, obese participants (group C, n = 32) in the 6-month BOOCS program, and most patients in groups B and C (86.9 %) completed this program. Baseline mean erythrocyte filterabilities were 89.4 ± 1.7 % in group A, 82.8 ± 5.2 % in group B, and 84.1 ± 5.6 % in group C, showing significant intergroup differences (p < 0.001). This program significantly improved (p < 0.001) the impaired erythrocyte filterability in groups B (87.9 ± 4.4 %) and C (88.5 ± 3.7 %). Declines in HbA1c (p = 0.387) and body mass index (p = 0.479) were not correlated to this improvement. These findings indicate that the mechanisms of BOOCS-induced improvement of diabetic or obese patients' erythrocyte deformability are multifactorial, and that the BOOCS program for these patients is a holistic, cost-effective, and highly compliant approach possibly ameliorating microcirculation.

Expression profiles of genes associated with viral entry in HCV-infected human liver

Recent studies have demonstrated that several cellular factors are involved in entry of hepatitis C virus (HCV) into host cells. Detailed gene expression profiles of these factors in HCV-infected livers have not been reported for humans. Transcriptional levels of LDL receptor (LDLR), CD81, scavenger receptor class B type I (SR-BI), claudin-1, and occludin genes in liver samples from patients with chronic hepatitis C were investigated. Serum levels of LDL-cholesterol (LDL-C) and HCV core antigen were also evaluated, and expression of claudin-1 and occludin were immunohistochemically analyzed. Compared with normal liver, transcription of LDLR and claudin-1 genes was significantly suppressed (P < 0.0001) and occludin transcription was significantly up-regulated in HCV-infected livers (P < 0.0001). Significant positive correlations were found for LDLR versus occludin, LDLR versus claudin-1, occludin versus claudin-1, and CD81 versus SR-BI in HCV-infected (P = 0.0012, P < 0.0001, P = 0.0004, and P < 0.0001, respectively) and normal livers (P < 0.0001, P = 0.0051, P < 0.0001, and P < 0.0001, respectively). Positive correlation was observed between serum levels of HCV core antigen and LDL-C (P = 0.0147), with their levels negatively correlated to LDLR (P = 0.0270 and P = 0.0021, respectively). Immunohistochemically, hepatocellular expression of claudin-1 and occludin was increased in HCV-infected livers. Different levels of expression were demonstrated at the mRNA and protein levels for occludin and claudin-1 in HCV-infected and normal livers. Correlation of elements associated with viral entry was comparable in HCV-infected and normal livers.

Two cyanobacterial strains can be distinguished from each other and other eukaryotic algae by spectral absorption method

Spectral absorption method based on two step linear regression analyses (TSLR) was applied for detection of two strains of cyanobacterium, Microcystis (blue-green algae) from eukaryotic algae. Both blue-green algae, algae and dissolved organic carbon (DOC) were considered from freshwater bodies in Kanto region, Japan. The results show that blue-green species can be detected from other algal species using absorption spectra of water samples. In this study statistical analysis was done by TSLR method, which determined the gradient vectors of single algal species and DOC. We believe that this method might be useful in environmental monitoring of freshwater algae.

Menopausal status influences the relationship between serum ghrelin levels and fat mass in healthy women

OBJECTIVE

To examine the relationships of fasting serum ghrelin levels to bone mass index (BMI) and body fat mass, focusing on the effects of menopausal status and changes in fat distribution in women after menopause.

DESIGN

An observational study.

PATIENTS

Fifty-nine pre-menopausal and 31 post-menopausal healthy Japanese women volunteers were enrolled in the present study.

MEASUREMENTS

Total and regional body fat mass weight was measured by dual energy x-ray absorptiometry. Serum ghrelin was measured. Relationships of serum ghrelin levels to weight, BMI, total body and regional fat mass weight were separately examined in post-menopausal and pre-menopausal women.

RESULTS

Serum ghrelin levels were significantly inversely correlated with weight (r = -0.377, p < 0.05, Pearson's correlation test), right arm fat mass (r = -0.408, p < 0.05), left arm fat mass (r = -0.386, p < 0.05), trunk fat mass (r = -0.361, p < 0.05) and total body fat mass (r = -0.383, p < 0.05) in the post-menopausal women but not in pre-menopausal women.

CONCLUSIONS

Menopausal status may influence the relationship between serum ghrelin levels and fat mass in healthy women.

Improvement of scopolamine-induced memory impairment by Z-ajoene in the water maze in mice

Z-ajoene, a major compound containing sulfur in oil-macerated garlic products, exhibited inhibitory effects against scopolamine-induced memory impairment in mice using the Morris water maze test. The effects of Z-ajoene were observed dose-dependently (0.25-25 mg/kg). At the highest dosage, the memory performance of mice was improved compared to normal mice. The acetylcholinesterase (AChE) activity in the brain was reduced by administration of Z-ajoene dose-dependently. However, alliin and diallyl disulfide, organosulfur compounds from garlic, did not improve memory performance nor AChE inhibitory effect. These results suggest that Z-ajoene may act on the cholinergic system and on memory impairment caused by excess activity of AChE.

The leptin receptor in human osteoblasts and the direct effect of leptin on bone metabolism

It is important to elucidate whether the leptin receptor, especially the long signal-transducing form of the leptin receptor (OB-Rb) is expressed in human osteoblasts. We detected the expression of human OB-Rb in cultured commercially available human osteoblasts (NHOst cells) using real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). After confirming the expression of OB-Rb, we investigated the effect of leptin on NHOst cells. Leptin enhanced cell proliferation of the cells shown by the MTT assay. Furthermore, leptin changed the copy numbers of Bax and Bcl-2 mRNAs in the cultured cells as shown by real-time quantitative RT-PCR, although the effect was not consistent. Leptin did not change the production of osteocalcin and osteopontin by the cells. Leptin did not change the expression of OB-Rb mRNA in the cells. In conclusion, OB-Rb mRNA is expressed in cultured commercially available human osteoblasts. Leptin may have some effects on bone metabolism by directly modulating cell proliferation and apoptosis of osteoblasts in humans.

Bone mineral density of the lumbar spine is associated with TNF gene polymorphisms in early postmenopausal Japanese women

We investigated the relationships between tumor necrosis factor (TNF) gene polymorphism, circulating TNF-alpha (TNF-alpha) concentrations, and bone mineral density (BMD) in the lumbar spine. TNF gene polymorphisms studied were the Nco I polymorphism within the first intron of TNF-beta (TNF-beta) and three single nucleotide polymorphisms in the promoter region of the TNF-alpha gene, at positions -857, -863, and -1031. Allelic variants of the TNF gene were identified using restriction fragment length polymorphism (RFLP) analysis in 177 postmenopausal Japanese women within 10 years after menopause, aged 56.4 +/- 4.5 years (mean +/- SD). A significantly higher prevalence of the alleles TNF-alpha-863A (20.3% versus 9.9%) and TNF-alpha-1031C (21.3% versus 12.4%) was seen in the low BMD group (Z-score < 0, n = 91) than in the high BMD group (0 < Z-score, n = 86). In genotype analysis, although difference did not reach a significant level, women with the rarest allelic variants, i.e., homozygous TNFbl, TNF-alpha-863A, and TNF-alpha-1031C, showed the lowest BMD Z-scores. Women with another rarest allelic variant, TNF-alpha-857T/T had significantly lower BMD Z-scores than did women with TNF-alpha-857C/T or -857C/C. The BMD Z-score decreased significantly with an increase in the total number of such rare alleles. Serum concentrations of TNF-alpha did not differ significantly among groups divided by genotypes. Multiple linear regression analysis revealed that the total number of rare alleles, in addition to the body mass index and the number of years since menopause, was an independent predictor of the BMD. These presumptive functional polymorphisms of the TNF gene may be associated with the lumbar spine BMD in early postmenopausal Japanese women.

A gene for a Class II DNA photolyase from Oryza sativa: cloning of the cDNA by dilution-amplification

Ultraviolet radiation induces the formation of two classes of photoproducts in DNA-the cyclobutane pyrimidine dimer (CPD) and the pyrimidine [6-4] pyrimidone photoproduct (6-4 product). Many organisms produce enzymes, termed photolyases, which specifically bind to these lesions and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. Two classes of photolyases (class I and class II) repair CPDs. A gene that encodes a protein with class II CPD photolyase activity in vitro has been cloned from several plants including Arabidopsis thaliana, Cucumis sativus and Chlamydomonas reinhardtii. We report here the isolation of a homolog of this gene from rice (Oryza sativa), which was cloned on the basis of sequence similarity and PCR-based dilution-amplification. The cDNA comprises a very GC-rich (75%) 5; region, while the 3; portion has a GC content of 50%. This gene encodes a protein with CPD photolyase activity when expressed in E. coli. The CPD photolyase gene encodes at least two types of mRNA, formed by alternative splicing of exon 5. One of the mRNAs encodes an ORF for 506 amino acid residues, while the other is predicted to code for 364 amino acid residues. The two RNAs occur in about equal amounts in O. sativa cells.

Tegumentary papillae of Echinostoma caproni cercariae (Trematoda: Echinostomatidae)

Argentophilic staining and scanning electron microscopy were used to study the tegumentary papillae of Echinostoma caproni cercariae. The most abundant tegumentary papillae were uniciliate, but multiciliate papillae were also found, mainly on the ventral aspect of the oral collar. The distribution pattern of the papillae on the body and tail was in general similar to that seen in the cercariae of other 37-collar-spined Echinostoma species. Some differences were noted between E. caproni and the allopatric species, E. trivolvis. E. caproni has a greater number of papillae associated with the collar spines than does E. trivolvis. E. caproni has uniciliate papillae on the acetabulum, whereas E. trivolvis does not. Chaetotaxy is useful to distinguish subtle morphological differences in cercarial species in the 37-collar-spined Echinostoma complex.

Hyperosmotic stimuli induces recruitment of aquaporin-1 to plasma membrane in cultured rat peritoneal mesothelial cells

Aquaporin-1 (AQP-1) has been reported to play an important role in peritoneal dialysis. To determine the precise mechanism involved, we used cultured rat peritoneal mesothelial cells (RPMCs) to examine the translocation of AQP-1 to the plasma membrane induced by hyperosmotic stimuli. Cultured RPMCs obtained from male Sprague-Dawley rats were incubated at room temperature in Dulbecco modified Eagle medium/F12 (DMEM/F12) with and without glucose or mannitol as the hyperosmotic stimulus. The plasma membrane was then extracted by the Percoll gradient method. Finally, the abundance AQP-1 molecules in the membrane fraction was determined by Western blot analysis. Significant enhancement of AQP-1 abundance (p < 0.05) was observed within 2.5 minutes of the addition of 5% glucose to the medium. The increase was sustained in its abundance through 15 minutes. Abundance of AQP-1 was also increased (p < 0.05) by the addition of 5% mannitol. These results suggest that hyperosmotic stimuli could generate increased AQP-1 abundance in the plasma membrane by translocation of AQP-1 protein from recycling endosomes or early endosomes to the plasma membrane, rather than by protein synthesis via newly expressed mRNA. The latter mechanism would be expected to take more time.

Serum levels of vascular endothelial growth factor and cavity formation in active pulmonary tuberculosis

BACKGROUND

In active pulmonary tuberculosis, certain cytokines have been postulated to be related to cavity formation, although the detailed mechanism of cavity formation is not yet known.

OBJECTIVE

We examined the relationship between cavity formation in pulmonary tuberculosis and vascular endothelial growth factor (VEGF), which functions as an angiogenesis factor.

METHODS

Forty-eight patients with active pulmonary tuberculosis were divided into two groups according to cavity formation as evaluated by chest high-resolution computed tomography. We evaluated serum VEGF levels by enzyme immunoassay.

RESULTS

Group A (with cavities) was comprised of 22 patients and group B (without cavities) was comprised of 26 patients. The serum levels of VEGF were significantly higher in group B (58.733 +/- 21.612 pg/ml) than those in normal individuals (8.739 +/- 3.656 pg/ml) and in group A (13.053 +/- 8.670 pg/ml) (Mann-Whitney U test, p = 0.0149 and p = 0.0481, respectively). Serum levels of interleukin-8 and tumor necrosis factor-alpha were not significantly different between the two groups.

CONCLUSION

These findings suggested that increased serum VEGF levels subdue cavity formation in active pulmonary tuberculosis.

Molecular heterogeneity of heat-stable toxin-producing and non-producing Escherichia coli O25 strains isolated in Japan

Escherichia coli O25 strains that produce heat-stable toxin (ST) have been recently isolated in Japan, and epidemiological study of this type of enterotoxigenic E. coli is required. In this study the heterogeneity of 16 ST-producing and non-producing strains of E. coli O25 was investigated. All eight ST-producing strains were shown to have STIb gene, and seven of them had similar profiles of plasmids, ladder-banding of LPS in SDS-polyacrylamide gel electrophoresis, and chromosomal DNA digestions in pulsed-field gel electrophoresis (PFGE). In contrast, ST-non-producing strains were more heterogeneous in all parameters examined. PFGE of the digested chromosomal DNA with several restriction enzymes was proved to be an effective procedure to compare the closely related strains of E. coli O25.

Subthreshold stimulation in three types of reentrant supraventricular tachycardia: correlation with the results of catheter ablation

The effects of subthreshold stimulation (STS) by direct current were investigated in 20 patients with atrioventricular nodal reentrant tachycardia (AVNRT), 27 with atrioventricular reentrant tachycardia (AVRT) and 3 with idiopathic atrial reentrant tachycardia (IART) STS was delivered to each eligible site for ablation prior to radiofrequency application. STS was defined as 'positive' if it could terminate the tachycardia or disrupt the conduction of accessory pathways without myocardial capture and defined as 'negative' if it could not. Radiofrequency ablation was performed irrespective of a positive or negative result from STS and was successful in all 50 patients. Among the 50 successful ablation sites, STS was positive at 26 sites (11 sites in AVNRT, 12 in AVRT and 3 in IART). STS was positive at 4 sites where ablation failed in 3 patients with AVRT and was negative at 8 sites where ablation was successful in 4 patients with AVNRT and 4 with AVRT. The positive and negative predictive value of STS for the detection of the optimal ablation site were, respectively, 100% and 74% in AVNRT, 73% and 72% in AVRT, and both 100% in IART STS-guided mapping is a specific method to predict the successful catheter ablation of reentrant supraventricular tachycardia.

Protective effect of ajoene on acetaminophen-induced hepatic injury in mice

Ajoene, a garlic-derived sulfur-containing compound, exhibited a hepatoprotective effect against acetaminophen-induced liver injury in mice. A pretreatment with ajoene suppressed the rise in serum glutamic-pyruvic transaminase activity and the reduction in the hepatic reduced glutathione level. These effects of ajoene were observed dose-dependently (20-100 mg/kg). The pretreatment by ajoene also suppressed the decrease in hepatic protein thiol content resulting from acetaminophen administration.

Histopathological prognostic factors of adult granulosa cell tumors of the ovary

BACKGROUND

The prognostic factors of adult granulosa cell tumor (AGCT) have not been well defined.

METHODS

In 27 AGCT patients, we examined clinical stage, microscopic patterns, mitotic index (MI), and lymph-vascular space invasion (LVSI) to determine whether these factors were related to disease-free survival (DFS) of patients with AGCT. We also performed immunohistochemical examination for p53.

RESULTS

Seventeen cases represented stage I tumors, four stage II, five stage III, and one stage IV. Patients with stage I disease had more favorable prognosis than those with stage II to IV disease (p=0.034). There was no relation between the microscopic patterns and the DFS. The MI, which was categorized into < or =3/10 high power field (HPF) and > or =4/10 HPF, was significantly related to patients DFS (p<0.0005). The DFS time for patients with moderate or prominent LVSI was significantly shorter than that for patients with no or minimal LVSI (p<0.0001). By multivariate analysis, MI and LVSI were shown to be independent prognostic factors. Five of seven patients with recurrent tumor had extrapelvic spread; two in the abdominal cavity and three in the liver.

CONCLUSION

The results of this study suggest that prognosis for patients with AGCT depends on the MI and LVSI. During the follow-up period of patients, they need to be examined for distant metastasis including liver.

Genomic organization and transcription units of the human acyl-CoA synthetase 3 gene

Acyl-CoA synthetases (ACSs) play an essential role in fatty acid metabolism. ACS3 is an arachidonate-preferring enzyme expressed in a wide range of human tissues including brain, heart, placenta, prostate, skeletal muscle, testis and thymus. As an initial step to understanding the transcriptional regulation of the human ACS3 gene, we analyzed the genomic organization and transcription units of the human ACS3 gene. Sequence analysis of genomic clones demonstrates that the human ACS3 gene spans at least 80.6 kb and contains 17 exons. The human ACS3 gene was mapped between the sequence-tagged site markers D2S360 and WI-21901. Sequence inspection of the 5'-flanking region revealed potential DNA elements including CCAAT, AP-1, Oct-1, GATAs, SRY, CdxA, Nkx-2.5, c-Myb, HSF2, NF-AT, AP-2, NF-Y, and p300. A minimal promoter region required for the expression of the human ACS3 gene in melanoma G361 cells was determined.

Roles of prostaglandin I(2) and thromboxane A(2) in cardiac ischemia-reperfusion injury: a study using mice lacking their respective receptors

BACKGROUND

Prostaglandin (PG) I(2) and thromboxane (TX) A(2), the most common prostanoids in the cardiovascular system, are produced abundantly during cardiac ischemia/reperfusion (I/R); their roles in I/R injury, however, remain undetermined. We intended to clarify these roles of PGI(2) and TXA(2) using mice lacking the PGI(2) receptor, IP(-/-) mice, or the TXA(2) receptor, TP(-/-) mice.

METHODS AND RESULTS

The left anterior descending coronary artery was occluded for 1 hour and then reperfused for 24 hours. The size of myocardial infarct in IP(-/-) mice was significantly larger than that in wild-type mice, although the size of the area at risk was similar between the 2 groups of mice. In contrast, there was no such difference between TP(-/-) and wild-type mice. To further determine whether PGI(2) and TXA(2) act directly on the cardiac tissue or indirectly through their action on blood constituents, we perfused excised heart according to the Langendorff technique. The isolated heart was then subjected to global ischemia followed by reperfusion. In IP(-/-) mice, developed tension and coronary flow rate during reperfusion were significantly lower and release of creatine kinase was significantly higher than those in wild-type mice. There were no such differences, however, between TP(-/-) and wild-type mice.

CONCLUSIONS

PGI(2), which was produced endogenously during cardiac I/R, exerts a protective effect on cardiomyocytes independent of its effects on platelets and neutrophils. In contrast, TXA(2) has little role in the cardiac I/R injury.