Porphyromonas gingivalis mutant defective in a putative extracytoplasmic function sigma factor shows a mutator phenotype

INTRODUCTION

Porphyromonas gingivalis is implicated as a major pathogen in the development and progression of chronic periodontitis. P. gingivalis must possess the ability to tolerate stress signals outside the cytoplasmic membrane by transcriptional activation of genes encoding proteins involved in defense or repair processes. Some bacteria utilize a distinct subfamily of sigma factors to regulate extracytoplasmic function (hence termed the ECF subfamily).

METHODS

To elucidate their role in P. gingivalis, a chromosomal mutant carrying a disruption of an ECF sigma factor PG1318-encoding gene was constructed. Hemagglutination and proteolytic activities were measured in the PG1318-defective mutant. Reverse transcription-polymerase chain reaction (RT-PCR) analysis and southern blot analysis were used to assess transcription of kgp in the PG1318-defective mutant. Frequency of spontaneous mutation that conferred resistance to l-trifluoromethionine was measured in the PG1318-defective mutant.

RESULTS

The PG1318-defective mutant formed non-pigmented colonies on blood agar plates at a relatively high frequency. Arginine-specific and lysine-specific proteinase activities of the non-pigmented variants were remarkably decreased compared with those of the parent strain and the pigmented variants. RT-PCR analysis showed that kgp was not transcribed in some non-pigmented variants and southern blot analysis revealed that there was a deletion in their kgp region. Frequency of mutation conferring resistance to l-trifluoromethionine was significantly higher in the PG1318-defective mutant than in the wild-type.

CONCLUSION

These results suggest that PG1318 plays a role in the regulation of mutation frequency in the bacterium.

Effort-reward imbalance and depressive state in nurses

BACKGROUND

The mental health of nurses is an important issue.

AIMS

To examine relationships between effort-reward imbalance (ERI) and depression and anxiety in nurses of a Japanese general hospital.

METHODS

A self-report survey was conducted among 406 nurses. Work stress was measured using a Japanese version of the ERI scale. Depression and anxiety were assessed by an item of the QOL-26. Logistic regression analysis was used to determine the independent contribution of the effort-reward ratios or overcommitment to the depressive state.

RESULTS

Both higher effort-money ratio and higher overcommitment significantly correlated with the depressive state (OR: 2.75; 95% CI: 1.34-5.66 and OR: 1.27; 95% CI: 1.15-1.41, respectively).

CONCLUSIONS

These findings suggest that in addition to effort-money ratio, overcommitment at work is an especially important issue that may be able to be managed in health promotion services for nurses in general hospitals.

Prognostic impact of calf muscle near-infrared spectroscopy in patients with a first episode of deep vein thrombosis

BACKGROUND

The risk factors that affect the development of post-thrombotic syndrome (PTS) are not fully recognized, and it is difficult to reliably predict which patients are likely to develop PTS in acute phase of deep vein thrombosis (DVT).

AIMS

To investigate changes in calf muscle deoxygenated hemoglobin (HHb) levels after DVT, and to determine the indicative parameters reflecting the progression of PTS.

METHODS

Seventy-six consecutive patients with a first episode of unilateral DVT were prospectively enrolled. Clinical manifestations were categorized according to the CEAP (Clinical, Etiologic, Anatomical, and Pathophysiologic) classification, and the patients were divided into no-PTS (C(0-3)E(s),A(s,d,p),P(r,o)) and PTS (C(4-6)E(s),A(s,d,p),P(r,o)) groups. Near-infrared spectroscopy (NIRS) was used to measure calf muscle HHb levels at 6 months after diagnosis of DVT. The calf venous blood filling index (HHbFI) was calculated on standing, and the venous ejection index and the venous retention index (HHbRI) were then obtained after exercise. All patients were followed up for more than 24 months after the diagnosis of DVT.

RESULTS

Of 76 patients evaluated, 20 (26.3%) had PTS. The NIRS-derived HHbFI and HHbRI were significantly increased in patients who developed PTS in comparison with those who did not (P = 0.04 and P = 0.0001, respectively). HHbRI was significantly increased in patients with iliofemoral DVT in comparison with patients with calf DVT (P = 0.041). An optimal cut-off point of 2.9 for HHbRI showed the strongest ability to predict the development of PTS, with a sensitivity of 100% and a specificity of 82.1%.

CONCLUSIONS

HHbRI as measured by NIRS is significantly increased in patients with iliofemoral DVT as compared with those with calf DVT. Furthermore, HHbRI > 2.9 is a strong predictor of the development of PTS at 6 months.

Effects of weekly bevacizumab and pegylated liposomal doxorubicin in heavily pretreated patients with recurrent or progressed ovarian cancer

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Background: Vascular endothelial growth factor (VEGF) plays a central role in tumor angiogenesis and is regarded a promising therapeutic target. Bevacizumab (A) has significant antitumor activity in combination with cytotoxic agents. Currently, pegylated liposomal doxorubicin (D) is provided as one of the standard treatment options in recurrent ovarian cancer. Thus, we attempted to determine effects in combination of A and D for heavily pretreated patients with recurrent or progressed ovarian cancer. Methods: Twenty-two patients with heavily pretreated (more than one regimen or more than 6 cycles by paclitaxerl and carboplatin) received at least more than 3 cycles of weekly A-D consisting of A: 2 mg/kg and D: 10 mg/m2 (3 weeks, one week rest). The primary endpoint was response according to CA 125 and response evaluation criteria in solid tumor (RECIST) criteria. Results: Of 22 patients evaluable for CA 125 response, 7 (32%) had a response (decrease of >50%), and 8 (36%) patients had not progressed (doubling of CA 125) following 6 months on treatment. In RECIST evaluation, 2 (9%) patients had complete remission (CR) and 6 (27%) had partial remission (PR), resulting in 55% clinical benefit rate (CBR). Progression free interval (PFI) showed more than 6 months. Any hematological adverse effect was not observed in the present study. Gastrointestinal perforation was observed in only one case and was conservatively treated. Although nasal bleeding was frequently observed, no treatment was required. A induced hypertension was also observed and manageable. Hand-foot syndrome seemed due to D was seen in 3 of 22 patients and treatment was required in only one case. Conclusions: B seemed to enhance effect of D. This is the first study of weekly A-D in heavily pretreated ovarian cancer patients. Weekly A-D warrants further clinical study in such clinical settings.

No significant financial relationships to disclose.

Efficient production of single-chain Fv antibody possessing rare codon linkers in fed-batch fermentation

Single-chain Fv antibody (scFv) having 2 types of polypeptide linkers with or without rare codons, namely scFv (G(4)S)(3)(R) and scFv No.10 (with rare codons) and scFv (G(4)S)(3) and scFv No.10(NR) (without rare codon), were expressed under controllable conditions in batch and fed-batch fermentation, in order to compare volumetric productivity and specific productivity levels of scFvs as a soluble form. In batch fermentation, volumetric productivity levels of scFv (G(4)S)(3)(R) and scFv No.10, namely scFvs having the rare codon linkers were 3-5 times higher than those of scFvs that had linkers without the rare codon. In fed-batch fermentation controlled by an exponential feeding system, the cell concentrations of the transformants increased with similar specific growth rates (0.1 h(-1)), while the specific productivity levels of scFvs with the rare codon linkers were 1.6 times higher than those of scFvs without the rare codon linkers. These results indicate that the presence of several rare codons in the gene of a polypeptide linker increases soluble amount of scFvs. This might be caused by a temporary decrease in translation speed at the position of the polypeptide linker allowing time for the folding of the V(H) domain and avoiding unfavorable interactions between amino acid residues at the unfolded V(H) and V(L) domains. Higher specific productivity levels of both scFv No. 10 and scFv No. 10(NR) than those of scFv (G(4)S)(3)(R) and (G(4)S)(3) might be caused by difference in stability of the polypeptide linkers on the basis of amino acid sequences. Thus, the rare codon linkers tested in this study will be considerably useful for large-scale production of soluble and active scFvs in fed-batch or continuous fermentations, in which high cell activity can be maintained.

Volcanic sulfur dioxide and acute respiratory symptoms on Miyakejima island

OBJECTIVES

Following a volcanic eruption in 2000, high concentrations of ambient sulfur dioxide (SO2) are still observed on Miyakejima, Japan despite the reversal 2 years ago of the ban on residents living on the island. This study examines the association between current levels of volcanic SO2 and the incidence of acute subjective symptoms in volunteers on Miyakejima.

METHODS

The authors conducted a follow-up study on 611 healthy volunteers, on a person-hour basis (28 413 person-hours), who visited the island to provide support to residents from February to July 2005. Adverse health symptoms were measured by self-administered diary and exposure was approximated using monitoring data across 14 sites. Associations between incidence rates and increasing SO2 levels (reference (the lowest), very low, low, middle and high) were examined using Poisson regression.

RESULTS

Hourly incidence of cough, scratchy throat, sore throat and breathlessness showed clear exposure-response relationships with SO2 concentrations. There were statistically significant risks of those symptoms at relatively low SO2 levels. Thus, rate ratios in the 0.6-2.0 ppm exposure band (vs <0.01 ppm) were: for cough, 3.4 (95% CI 1.8 to 6.6) in men and 9.8 (3.9 to 24.9) in women; for sore throat, 3.2 (1.7 to 6.2) in men and 5.8 (2.0 to 16.5) in women; and for breathlessness, 10.5 (4.2 to 26.6) in men and 18.5 (4.6 to 74.3) in women. Little evidence of SO2 effects on sputum and nasal discharge/congestion was observed in this study. Eye and skin irritations showed inconsistent results between hourly maximal and hourly mean SO2 concentrations.

CONCLUSION

The authors observed strong evidence of an exposure-response relationship between volcanic SO2 and subjective acute respiratory symptoms among a healthy population on Miyakejima. The results are consistent with reports that females and non-smokers are more sensitive to irritant gas than males and smokers, respectively.

Primary clear cell carcinoma of the peritoneum: report of two cases and a review of the literature

The most common neoplasms of the peritoneum are malignant mesothelioma and serous papillary adenocarcinoma. Clear cell carcinoma (CCC) is mostly derived from the ovary and often associated with endometriosis. We describe the clinicopathologic features of two cases diagnosed as CCC of the peritoneum origin. Case 1, a 53-year-old woman, presented with upper abdominal and pelvic tumors. Case 2, a 66-year-old woman, presented with massive ascites and abdominal tumor. The ovaries and uterine endometrium of these cases were not affected, and the tumors were diagnosed as Stage IIIc CCC of the peritoneum origin. Pathologically, endometriosis was not observed in either case. Adjuvant chemotherapy using irinotecan and cisplatin was effective in one case. The cases and a review of the literature suggested that residual tumor volume size determines the survival of these patients, and that the tumors show resistance to conventional platinum-based chemotherapy.

Chronic expanding hematoma in combination with a pseudoaneurysm: a case report

After bleeding from trauma or surgery, most of the hematomas undergo spontaneous reabsorption. But, in some rare cases, hematomas persist for long periods as slowly expanding masses for months or years. These hematomas were termed as chronic expanding hematomas. In this report, we describe a case of chronic expanding hematoma with a pseudoaneurysm that underwent surgical biopsy, which led to an increase in its expansion speed.

Mobile phone use, exposure to radiofrequency electromagnetic field, and brain tumour: a case-control study

In a case–control study in Japan of brain tumours in relation to mobile phone use, we used a novel approach for estimating the specific absorption rate (SAR) inside the tumour, taking account of spatial relationships between tumour localisation and intracranial radiofrequency distribution. Personal interviews were carried out with 88 patients with glioma, 132 with meningioma, and 102 with pituitary adenoma (322 cases in total), and with 683 individually matched controls. All maximal SAR values were below 0.1 W kg⁻¹, far lower than the level at which thermal effects may occur, the adjusted odds ratios (ORs) for regular mobile phone users being 1.22 (95% confidence interval (CI): 0.63–2.37) for glioma and 0.70 (0.42–1.16) for meningioma. When the maximal SAR value inside the tumour tissue was accounted for in the exposure indices, the overall OR was again not increased and there was no significant trend towards an increasing OR in relation to SAR-derived exposure indices. A non-significant increase in OR among glioma patients in the heavily exposed group may reflect recall bias.

[Freestyle valve for right ventricular reconstruction in Ross operation; report of a case]

A 28-year-old man with active aortic valve endocarditis underwent emergency surgery. Because he had progressive congestive heart failure and uncontrolled infection. Aortic root replacement for Ross procedure was required because of complete debridment of infective tissue. His operation were performed under extracorporeal circulation and moderate hypothermia, the operation procedure was following, (1) taking off auto-pulmonary artery valve, (2) removing dysfunctional aortic valve and auto-transplantation of pulmonary valve on aortic root, (3) putting a pulmonary Freestyle Aortic Valve to rebuild right ventricular outflow tract. Follow-up showed heart function was in class I (New York Heart Association) , aortic and pulmonary valve function was very well. Streptococcus milleri group was isolated from his blood and infectious aortic valve postoperatively. We believed that a Ross operation with Freestyle Aortic Valve is more resistant to infection, therefore, it might be an option for infective endocarditis with aortic valve endocarditis.

Increase of RP105-lacking activated B cells in the peripheral blood and salivary glands in patients with Sjögren's syndrome

OBJECTIVE

To quantify the activated B cells in the peripheral blood and salivary glands of patients with Sjögren's syndrome (SS) by analyzing the expression of RP105 molecule on the B cells.

METHODS

The expression of RP105 on the peripheral blood B cells of patients with SS (19 cases) was analyzed by flow cytometry. RP105-positive and negative B cells were sorted and cultured in vitro and the amount of immunoglobulins (IgG and IgM) produced in the supernatant was measured by enzyme-linked immunosorbent assay (ELISA). Salivary gland biopsy samples from 9 SS patients were histologically evaluated and the sequential frozen sections were separately immunostained by anti-RP105 and anti-CD20 monoclonal antibodies.

RESULTS

A significantly higher proportion of peripheral blood RP105-negative B cells was found in SS patients than in healthy individuals. RP105-negative, but not positive, B cells from SS patients were capable of producing IgG and IgM spontaneously in vitro, which was enhanced by the addition of Staphylococcus aureus Cowan I strain (SAC) or IL-6. Salivary glands from 2 of 9 SS patients were found to have lymphoid follicles whose germinal centers consisted of RP105-negative B cells. Moreover, a larger proportion of B cells extensively infiltrating the area other than lymphoid follicles was also RP105-negative.

CONCLUSION

RP105-negative B cells, a subset of highly activated and well differentiated B cells, which are increased in number in the peripheral blood and extensively infiltrate salivary glands, may be responsible for the production of class-switched immunoglobulin in SS. In addition, those cells might be associated with the inflammation and tissue damage of the salivary glands.

Low response rate of second-line chemotherapy for recurrent or refractory clear cell carcinoma of the ovary: a retrospective Japan Clear Cell Carcinoma Study

Clear cell carcinoma (CCC) of the ovary has been recognized to show resistance to anticancer agents in the first-line chemotherapy. Our aim was to evaluate the effect of second-line chemotherapy in a retrospective study. A total of 75 patients diagnosed with CCC and treated between 1992 and 2002 in collaborating hospitals were reviewed. Criteria for the patients' enrollment were 1) diagnosis of pure-type CCC at the initial operation, 2) treatment after one systemic postoperative chemotherapy, 3) measurable recurrent or refractory tumor, 4) at least two cycles of second-line chemotherapy and assessable for the response, and 5) adequate clinical information. Regimens of first-line chemotherapy were conventional platinum-based therapy in 33 cases, paclitaxel plus platinum in 24 cases, irinotecan plus platinum in 9 cases, and irinotecan plus mitomycin C in 7 cases. Treatment-free periods were more than 6 months in 24 cases (group A) and less than 6 months in 51 cases (group B). In group A, response was observed in two cases (8%): one with conventional platinum therapy and another with irinotecan plus platinum. In group B, three cases (6%) responded: two with platinum plus etoposide and one case with irinotecan plus platinum. Median overall survival was 16 months in group A and 7 months in group B (P = 0.04). These findings suggest recurrent or resistant CCC is extremely chemoresistant, and there is only small benefit of long treatment-free period in CCC patients. Another strategy including molecular-targeting therapy is warranted for the treatment of recurrent or refractory CCC.