Osteogenic potential of mandibular vs. long-bone marrow stromal cells

Although fundamentally similar to other bones, the jaws demonstrate discrete responses to developmental, mechanical, and homeostatic regulatory signals. Here, we hypothesized that rat mandible vs. long-bone marrow-derived cells possess different osteogenic potential. We established a protocol for rat mandible and long-bone marrow stromal cell (BMSC) isolation and culture. Mandible BMSC cultures formed more colonies, suggesting an increased CFU-F population. Both mandible and long-bone BMSCs differentiated into osteoblasts. However, mandible BMSCs demonstrated augmented alkaline phosphatase activity, mineralization, and osteoblast gene expression. Importantly, upon implantation into nude mice, mandible BMSCs formed 70% larger bone nodules containing three-fold more mineralized bone compared with long-bone BMSCs. Analysis of these data demonstrates an increased osteogenic potential and augmented capacity of mandible BMSCs to induce bone formation in vitro and in vivo. Our findings support differences in the mechanisms underlying mandible homeostasis and the pathophysiology of diseases unique to the jaws.

-93G>A polymorphism of hMLH1 associated with prognosis for patients with colorectal cancer

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Background: Polymorphisms in the DNA repair genes may contribute to variation in DNA repair capacity, thereby affecting the risk of carcinogenesis and prognosis of colorectal cancer. Accordingly, the present study analyzed polymorphisms of DNA repair genes and their impact on the prognosis for patients with colorectal cancer. Methods: Three hundred and ninety- seven consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and 14 polymorphisms of DNA repair genes (XRCC1, hMLH1, ERCC2, ERCC4, VARS2[rs2074511, rs2249459], XPA, XPC, POLR2A, POLR2B, RFC1, RFC4, XAB2, DNMT3B) determined using a PCR-RFLP assay. Results: The median age of the patients was 63 years (range, 21–85), and 218 (54.9%) patients had colon cancer and 179 (45.1%) patients rectal cancer. Pathologic stages after surgery were as follows: stage 0/I (n=86, 21.7%), stage II (n=146, 36.8%), stage III (n=145, 36.5%), and stage IV (n=20, 5.0%). Multivariate survival analysis including stage, differentiation, age, and CEA level showed that the survival for the patients with the -93AA genotype of hMLH1 was worse than for the patients with the combined -93GG and GA genotype (overall survival: hazard ratio [HR]=2.953, 95% Confidential Interval [CI], 1.273–6.850, P=0.012; disease-free survival: HR=2.299, 95% CI, 1.417–3.730, P=0.001), whereas the other polymorphisms were not associated with survival. Conclusions: The -93G>A polymorphism of hMLH1 was found to be an independent prognostic marker for patients with colorectal cancer. Accordingly, in addition to the pathologic stage, the analysis of -93G>A polymorphism of hMLH1 can help identify patient subgroups at high risk of a poor disease outcome.

No significant financial relationships to disclose.

Phase I dose-finding study of sorafenib in combination with capecitabine and cisplatin as a first-line treatment in patients with advanced gastric cancer

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Background: We conducted a phase I dose-finding study of sorafenib (S) in combination with capecitabine (X) and cisplatin (P) in patients with previously untreated metastatic or inoperable advanced gastric cancer. Methods: Four dose levels of S, X, and P combination were tested. The doses of S (p.o. daily), X (p.o. on days 1–14), and P (i.v. on day 1) were escalated at the following schedule; level 1: S 400 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 2: S 800 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 3: S 800 mg/d, X 2,000 mg/m2/d, P 80 mg/m2; level 1A: S 800 mg/d, X 1,600 mg/m2/d, P 60 mg/m2. The cycle was repeated every 3 weeks. Dose limiting toxicities (DLTs) were evaluated only in the first cycles and a standard 3+3 dose escalation design was implemented. Results: A total 21 pts were enrolled in the study. No DLTs were observed at dose level 1 (n=3). One DLT (grade 3 diarrhea) was noted at dose level 2 (n=6), and 2 DLTs (two grade 4 neutropenias longer than 5 days in duration) were observed at dose level 3 (n=6), which made the level 3 dose the maximum tolerated dose (MTD). However, at cycle 2 and thereafter at dose level 2, the relative dose intensity (RDI) of S and X could not be maintained (mostly below 80%) due to the frequent dose reductions and cycle delays. So, we explored a new dose level (1A) between dose level 1 and 2. Since no DLTs were found in 6 patients at level 1A with RDI mostly above 80% throughout the treatment period, level 1A was determined as recommended dose (RD). Most frequent grade 3 and 4 hematologic toxicities were neutropenia (25.0% of cycles), and most frequent grade 2 and 3 non-hematologic toxicities were hand-foot syndrome (9.4%), asthenia (7.0%), and anorexia (5.5%). The objective responses were confirmed in 10 out of 16 patients with measurable lesions (62.5%; 95% CI, 38.8–86.2%). With a median follow-up of 8.1 months, estimated median progression-free survival was 10.0 months (95% CI, 1.6–18.4 months) and median overall survival has not been reached. Conclusions: Diarrhea and neutropenia were DLTs in this S, X, and P combination. The dose schedule of sorafenib 400 mg po bid daily with capecitabine 800 mg/m2 po bid on days 1–14, and cisplatin 60 mg/m2 iv on day 1 in every 3 weeks is recommended for further development in AGC.

[Table: see text]

A phase II study of imatinib mesylate as adjuvant treatment for curatively resected high-risk localized gastrointestinal stromal tumors

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Background: In our previous study, the presence of c-kit mutation as well as tumor size and mitotic count was an independent poor risk factor for relapse after curative resection of primary localized GIST. The patients with all the 3 poor risk factors had only 30% of 2 year relapse free survival rate (RFSR). (Kim, et al. Clin Cancer Res, 2004) It is also well known that c-kit exon 11 mutant GISTs respond better to imatinib treatment than the other mutant or wild type GISTs. Therefore, the patients who have primary localized GISTs with large size, high mitotic count, and c-kit exon 11 mutation may be the best candidate of adjuvant imatinib treatment. In this phase II study, we have evaluated the efficacy and safety of adjuvant imatinib for this patient group. Methods: Patients who underwent complete resection of a primary GIST with 1) c-kit exon 11 mutation, and 2) ≥10 mitoses/50 HPF, or tumor size ≥10 cm, or ≥5 mitoses/50 HPF and tumor size ≥5 cm were eligible. Patients received imatinib 400mg p.o. daily until recurrence of disease, intolerable toxicities, or for 2 years. The primary end point was relapse-free survival (RFS). Results: A total of 47 patients from 4 centers in Korea were enrolled. The median age was 57.0 years. Stomach was the most common primary site (n=31). Median primary tumor size was 7.5cm and median mitoses index was 12/50 HPF. With a median follow-up of 26.9 months, the median RFS and overall survival (OS) have not yet been reached. RFSR was 97.7% at 1-year and 92.7% at 2-years. Six relapses (12.8%) were documented among the 47 patients. The treatments were generally well tolerated. Grade 3–4 toxicities included neutropenia 27.7%, rash 8.5%, constipation 4.3%, anorexia 2.1%, vomiting 2.1%, and pruritis 2.1%. There were no episode of febrile neutropenia and treatment-related death. Conclusions: Postoperative adjuvant imatinib for 2 years were safe and could prolong the RFS in patients with high-risk of recurrence following complete surgical resection of the primary GIST. However, it remains unknown if this benefit in RFS can be translated into OS benefit. So, further follow-up is needed with comparison of OS with historical controls who could be use imatinib after recurrence.

[Table: see text]

Prognostic impact of the NFKB1 insertion/deletion promoter polymorphism on survival in patients with surgically resected gastric cancer

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Background: The present study analyzed the functional insertion/deletion polymorphism in the promoter region of NKFB1 gene and their impact on the prognosis for patients with gastric adenocarcinoma. Methods: Five hundred and three consecutive patients with surgically resected gastric adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue and the -94 insertion/deletion ATTG polymorphism of NFKB1 determined using a PCR- RFLP assay. Results: The NFKB1 promoter gene polymorphism was successfully amplified in 97.8% of the cases. There were no sexual differences in relation to the genotype and allele. No correlation was observed between the frequency of the genotype or allele and the T, N, or M stage. The multivariate survival analysis showed no association between the NFKB1 -94 insertion/deletion promoter polymorphism and the disease-free survival or overall survival of the patients with gastric cancer. Conclusions: The functional NFKB1 promoter polymorphism was not found to be a prognostic marker for Korean patients with surgically resected gastric adenocarcinoma.

No significant financial relationships to disclose.

Expression of programmed cell death 5 gene involves in regulation of apoptosis in gastric tumor cells

The protein of programmed cell death 5 (PDCD5) is believed to participate in regulation of apoptosis. Although PDCD5 is reducibly expressed in various human tumors, it is not clear which expression level of PDCD5 is in gastric cancer (GC). In this study, we have systematically employed the approaches of RT-PCR, Real- time PCR, Immunohistochemistry (IHC), Immunofluorescence staining (IFS) and Western blot to determine the PDCD5 expression in GC cells and primary tumors, at mRNA and protein level, respectively. Our data revealed that the positive rate of PDCD5 expression in the gastric tumor tissues was significantly less than that of the normal tissues (14 out of 102 vs 36 out of 51), whereas, the decreased expression of PDCD5 protein was well correlated with the up-regulated expression of Bcl-2 in these tissues, and the up-regulated expression and nuclear translocation of PDCD5 protein were verified in the apoptotic GC cells induced by Diallyl trisulfide (DATS). Furthermore, the survival curve has suggested that the more PDCD5 expressions were found in the patients, the longer the survival periods were. Therefore, our observations lay down a reasonable postulation that PDCD5 may play a key role to regulate the apoptotic processes in the GC cells and gastric tumors.

Loss of myostatin (GDF8) function increases osteogenic differentiation of bone marrow-derived mesenchymal stem cells but the osteogenic effect is ablated with unloading

Myostatin (GDF8) is a negative regulator of skeletal muscle growth and mice lacking myostatin show a significant increase in muscle mass and bone density compared to normal mice. In order to further define the role of myostatin in regulating bone mass we sought to determine if loss of myostatin function significantly altered the potential for osteogenic differentiation in bone marrow-derived mesenchymal stem cells in vitro and in vivo. We first examined expression of the myostatin receptor, the type IIB activin receptor (AcvrIIB), in bone marrow-derived mesenchymal stem cells (BMSCs) isolated from mouse long bones. This receptor was found to be expressed at high levels in BMSCs, and we were also able to detect AcvrIIB protein in BMSCs in situ using immunofluorescence. BMSCs isolated from myostatin-deficient mice showed increased osteogenic differentiation compared to wild-type mice; however, treatment of BMSCs from myostatin-deficient mice with recombinant myostatin did not attenuate the osteogenic differentiation of these cells. Loading of BMSCs in vitro increased the expression of osteogenic factors such as BMP-2 and IGF-1, but treatment of BMSCs with recombinant myostatin was found to decrease the expression of these factors. We investigated the effects of myostatin loss-of-function on the differentiation of BMSCs in vivo using hindlimb unloading (7-day tail suspension). Unloading caused a greater increase in marrow adipocyte number, and a greater decrease in osteoblast number, in myostatin-deficient mice than in normal mice. These data suggest that the increased osteogenic differentiation of BMSCs from mice lacking myostatin is load-dependent, and that myostatin may alter the mechanosensitivity of BMSCs by suppressing the expression of osteogenic factors during mechanical stimulation. Furthermore, although myostatin deficiency increases muscle mass and bone strength, it does not prevent muscle and bone catabolism with unloading.

Mannan-modified adenovirus as a vaccine to induce antitumor immunity

Tumor vaccine is a useful strategy for cancer therapy. However, priming of the immune system requires the relevant antigen to be presented by antigen-presenting cells (APCs). Here, we employed telomerase reverse transcriptase as a model antigen to explore the feasibility of using mannan-modified adenovirus as a tumor vaccine. We found that tumor immunogene therapy with the vaccine was effective at protective antitumor immunity in mice. The antigen-specific cytotoxic T lymphocytes were found in in vitro cytotoxicity assay. The elevation of the killing activity could be abrogated by anti-CD8 or anti-major histocompatibility complex-I antibodies. Adoptive transfer of purified CD8+ cells, and CD4+ cells to a less extent, was effective at antitumor activity. In vivo antitumor activity could be abrogated by depleting CD4+ T lymphocytes. A possible explanation for the antitumor effects may be the antigen was transferred to APCs in the presence of mannan. These observations provide insights into the design of novel vaccine strategies and might be important for the future application of antigens identified in other diseases.

Magnetic microstructures and their dynamics studied by X-ray microscopy

Full-field soft X-ray microscopy in combination with X-ray magnetic circular dichroism as contrast mechanism is a powerful technique to image with elemental specificity magnetic nanostructures and multilayered thin films at high lateral resolution down to 15nm by using Fresnel zone plates as X-ray optical elements. Magnetization reversal phenomena on a microscopic level are studied by recording the images in varying external magnetic fields. Local spin dynamics at a time resolution below 100ps can be addressed by engaging a stroboscopic pump-and-probe scheme taking into account the time pattern of synchrotron storage rings. Characteristic features of magnetic soft X-ray microscopy are reviewed and an outlook into future perspectives with regard to increased lateral and temporal resolution is given.

Prevalence and genotyping of hepatitis E virus in swine population in Korea between 1995 and 2004: a retrospective study

Hepatitis E virus (HEV) infections have been reported in pigs throughout the world but have only recently been recorded in Korean pigs. The aim of this study was to investigate whether HEV was present in archived porcine hepatic tissues collected between 1995 and 2004 using RT-PCR and immunohistochemistry and, if so, to determine the genotype of the isolates. Swine HEV was identified in the liver tissue of 42 pigs of 388 submissions (four pigs every year on average). The isolates showed genetic homology with swine and human HEV isolates identified in the United States and Japan (92.5-97%) and phylogenetic tree analysis indicated they belonged to genotype III. The study indicates that HEV is not a newly emerging virus in Korean pigs, but a pathogen that has existed in the country since at least 1995.

Repeat induced abortions and contraceptive practices among unmarried young women seeking an abortion in China

OBJECTIVE

To determine the rates of repeated abortion and contraceptive use among unmarried young women seeking an abortion in China.

METHODS

We used an anonymous self-administered questionnaire at abortion clinics in Beijing, Changsha, and Dalian from January to September 2000.

RESULTS

Of 4547 unmarried young women seeking an abortion, 33.0% reported having had one previous induced abortion. Of those who had had more than one abortion, only 29.7% used a contraceptive method at their first sexual intercourse after the procedure; and of the 446 women who chose contraception, 41.3% used the traditional methods of withdrawal or rhythm. Although 65.0% of the young women had used condoms at least once, only 9.6% did so consistently and correctly; 47.7% of the current pregnancies were associated with nonuse of any contraceptive, and 52.3% were related to contraceptive failure.

CONCLUSION

The rate of unmarried young women seeking repeated abortions was high in China on 2000. The rate of consistent condom use was low, and the rate of contraceptive failure was higher.

Ultrasonographic diagnosis of bone tumor of the knee and its clinical implication

In order to evaluate the value of the ultrasonography in the diagnosis of tumor of the knee and its clinical implication, 67 patients with clinically suspected bone tumor of the knee were examined by ultrasound. The ultrasonographic characteristics of different bone tumors were studied and compared with the results of pathologic characters after operation. Ultrasonography can readily visualize the bony destruction and the pathologic change of the periosteum and the soft tissue related to bone tumor. Fifty-two cases of malignant bone tumors and 15 cases of giant cell tumors were diagnosed by ultrasonography. Pathologically, there were 54 cases of malignant bone tumor and 13 cases of giant cell tumor. It was concluded that ultrasonographic examination might be a useful method for the diagnoses of bone tumor of the knee and play an important role in guiding needle biopsy and electing operative method and approach.