β-Amyloid affects frontal and posterior brain networks in normal aging

Although deposition of β-amyloid (Aβ), a pathological hallmark of Alzheimer's disease (AD), has also been reported in cognitively intact older people, its influence on brain structure and cognition during normal aging remains controversial. Using PET imaging with the radiotracer Pittsburgh compound B (PIB), structural MRI, and cognitive measures, we examined the relationships between Aβ deposition, gray matter volume, and cognition in older people without AD. Fifty-two healthy older participants underwent PIB-PET and structural MRI scanning and detailed neuropsychological tests. Results from the whole-brain voxel-based morphometry (VBM) analysis revealed that gray matter volume in the left inferior frontal cortex was negatively associated with amyloid deposition across all participants whereas reduced gray matter volume was shown in the posterior cingulate among older people with high amyloid deposition. When gray matter density measures extracted from these two regions were related to other brain regions by applying a structural covariance analysis, distinctive frontal and posterior brain networks were seen. Gray matter volume in these networks in relation to cognition, however, differed such that reduced frontal network gray matter volume was associated with poorer working memory performance while no relationship was found for the posterior network. The present findings highlight structural and cognitive changes in association with the level of Aβ deposition in cognitively intact normal elderly and suggest a differential role of Aβ-dependent gray matter loss in the frontal and posterior networks in cognition during normal aging.

Specific and nonspecific neural activity during selective processing of visual representations in working memory

In this fMRI study, we investigated prefrontal cortex (PFC) and visual association regions during selective information processing. We recorded behavioral responses and neural activity during a delayed recognition task with a cue presented during the delay period. A specific cue ("Face" or "Scene") was used to indicate which one of the two initially viewed pictures of a face and a scene would be tested at the end of a trial, whereas a nonspecific cue ("Both") was used as control. As expected, the specific cues facilitated behavioral performance (faster response times) compared to the nonspecific cue. A postexperiment memory test showed that the items cued to remember were better recognized than those not cued. The fMRI results showed largely overlapped activations across the three cue conditions in dorsolateral and ventrolateral PFC, dorsomedial PFC, posterior parietal cortex, ventral occipito-temporal cortex, dorsal striatum, and pulvinar nucleus. Among those regions, dorsomedial PFC and inferior occipital gyrus remained active during the entire postcue delay period. Differential activity was mainly found in the association cortices. In particular, the parahippocampal area and posterior superior parietal lobe showed significantly enhanced activity during the postcue period of the scene condition relative to the Face and Both conditions. No regions showed differentially greater responses to the face cue. Our findings suggest that a better representation of visual information in working memory may depend on enhancing the more specialized visual association areas or their interaction with PFC.

71 DEVELOPMENT OF CLONED DOG EMBRYOS RECONSTRUCTED WITH PRE-ACTIVATED IN VIVO OOCYTES AND DONOR FIBROBLASTS ARRESTED AT G2/M PHASE USING ROSCOVITINE

The coordination between the cell cycle stages of nuclear donor cells and host oocytes has a critical effect on the development of embryos produced by somatic cell nuclear transfer (SCNT). Here, we investigated (1) whether roscovitine, an inhibitor of cyclin-dependent kinases (CDK) could arrest canine somatic cells at S/G2 phase of the cell cycle; (2) whether IVM metaphase II (MII) oocyte could be induced to telophase II (TII) after activation. Last, we investigated embryo development ability of nonactivated oocytes (MII) or activated oocytes (TII) fused with somatic cells at different stages of the cell cycle. Dog fetal fibroblasts were treated with roscovitine (30 or 60 μg mL-1 at 24, 48, or 72 h) and a control group of donor cells was cultured to reach confluency. The cells were then fixed and stained with 1 mg mL-1 propidium iodide for flow cytometric analysis. For SCNT, IVM dog oocytes were obtained by flushing (approximately 72 h after ovulation) from the oviducts of oocyte donor dog (Canis familiaris) and divided into 2 groups; nonactivated oocytes (MII) and activated oocytes (TII) by 10 μg mL-1 calcium ionophore for 4 min. Following preparation of each donor cell arrested in G0 and G2/M phase, cells of G0 stage were placed into enucleated MII oocytes (MII-G0) and cells of G2/M-phase were placed into enucleated TII oocytes (TII-G2/M). After fusion by electric stimulation, the MII-G0 group was chemically activated and cultured in modified SOF medium (mSOF), and the TII-G2/M group was cultured in mSOF without activation. The embryo developmental competence was estimated by assessing in vitro development under the microscope. Data were analyzed using a statistical analysis system program. Based on flow cytometry, the frequency of cells arrested at G2/M-phase in the 30 and 60 μg mL-1 roscovitine groups was significantly higher than that in control (31.95 and 25.99% v. 19.79%, respectively), but differences were not observed between the 30 and 60 μg mL-1 roscovitine groups (P > 0.05). Also, a significant increase in the proportion of cells at G2/M-phase was observed at 48 and 72 h in both roscovitine groups compared with the group not treated with roscovitine. The proportion of cells at G2/M-phase in the 60 μg mL-1 group at 48 h and the 30 μg mL-1 group at 72 h was the highest among all treatments. For the TII-G2/M group, we injected into enucleated TII oocyte and selected a large cell that arrested at G2/M-phase in cells cultured with 60 μg mL-1 roscovitine for 48 h. For the result of in vitro development of cloned embryo from MII-G0 and TII-G2/M, TII-G2/M group (39.4 and 7.8%) showed an increased cleavage rate and development to 8 cells compared with MII-G0 (23.5 and 2.9%). In the present study, we demonstrated that, in combination with nuclear donor cells at specific cell cycle stages, MII and TII dog oocytes are similarly effective in supporting the reprogramming of somatic cell nuclei. This study was supported by Korean MEST through KOSEF (grant # M10625030005-09N250300510) and BK21 program, RNL BIO, and Natural Balance Korea.

Comparison of Synchrotron Images of DCIS of the Breast with Their Pathologic Findings

Background: Synchrotron radiation x-ray imaging have opened a new door to explore breast tissue below the micron scale providing detailed internal structures of the samples with a great magnification and an excellent resolution. Using phase contrast technique, we got monochromated synchrotron images of DCIS (Ductal Carcinoma In Situ) of the breast tissue section. To figure out relation with their optical microscopic features, we compared the synchrotron images of the DCIS with their histopathologic findings of the same stained section.Material and Methods: A x-ray microscope was installed on 1B2 beamline of Pohang Light Source, a third generation synchrotron radiation facility with operating energy of 2.5 GeV in Pohang, Korea. The x-ray energy was set at 11.1 keV, and the x-ray beam was monochromatized by a W/B4C monochromator. Zernike phase-shifter was adapted for phase contrast x-ray microscopy. Formalin-fixed 5µm-thick breast tissue sample was attached onto the Kapton film, and positioned 25 m away from the beam source. The synchrotron image of sample was converted into a visual image on the CsI(TI) scintillation crystal, and this visual image was captured by a full frame CCD camera. After scanning, we patched these images one and another to show the large area of the tissue section. For the comparative analysis with their synchrotron image, synchrotron-scanned breast tissue sections were stained, and the histopathologic findings of the samples were captured by image analyzer. The magnifying power of this microscope was 100x.Results: The monochromated x-ray microscopic images of DCIS of the breast tissue were obtained with a good resolution. These images revealed various structures of DCIS lesion with a good contrast and high visibility by phase contrast technique. They include prominent and intact periductal basement membrane - a hallmark of DCIS lesion, and stippled fine microcalcifications which were indistinct in the histologic section, and a shadow of intense peritumoral inflammatory cell infiltration. But the minute changes of each cancer cell showing the features of cancer tissue such as, cellular differentiation and nuclear grade, were not identified well.Discussion: The x-ray microscopic imaging of DCIS of the breast tissue section with synchrotron radiation showed a good correspondence with the histopathologic findings of their stained tissue sections. And the synchrotron image of DCIS had some unique radiologic features differentiating from histopathogic findings. Therefore the synchrotron images of the DCIS lesion appear to have a new possibility of use for the clinical and research purposes in near future.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5015.

Impact of the income-based health service types on survival in patients with metastatic gastric cancer

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Background: Subscription to National Health Insurance (NHI) is a national obligation for South Korean people. For low-income citizens (about lower 3% of population), Medicaid is applied. Many recipients of Medicaid are vulnerable people such as old age singles, the homeless or the handicapped. These populations are suspected to have worse prognosis. According to one report, on the other hand, patients with Medicaid were more likely to receive chemotherapy than patients with NHI despite the uniform health insurance coverage within the two types of health cost financing. Owing to these conflicting findings, we investigated the relationship between health insurance type and prognosis. Methods: Patients are stage IV advanced gastric cancer patients who received palliative chemotherapy. Medical records were reviewed from January 2006 to November 2008 in Seoul Medical Center (municipal teaching hospital). Results: Total 37 patients were found. Median age was 61 years (range 31–85) and male constituted 75.7%. Platinum (cisplatin or oxaliplatin) combined with 5-FU was the most frequently used regimen (78.4%). Twelve patients (32.4%) were recipients of Medicaid. Median PFS and OS of NHI group were 6.9 (95% CI, 1.7–12.0) and 7.8 (95% CI, 3.4–12.1). And that of Medicaid were 5.6 (95% CI, 2.6–8.6) and 7.8 (95% CI, 3.4–12.2) months. The difference from two groups were not statistically different (p = 0.739 for PFS and 0.466 for OS). When patients were divided into longer or shorter survivors according to mean OS (14.1 ±2.6 months), NHI recipients had more probability for survival (odds ratio 0.72, 95% CI 0.56–0.92). Conclusions: The question is raised whether recipients of Medicaid have poorer prognosis than patients with NHI in metastatic gastric cancer in South Korea. Although it seems that NHI recipients has better prognosis, still we cannot sure. It should be cleared in large scale cohort study whether this is related to low socio-economic status or other uncontrolled confounder.

No significant financial relationships to disclose.

A novel laboratory cultivation method to examine antibiotic-resistance-related microbial risks in urban water environments

Although microbial risk due to antibiotic-resistant microbes in water has been a serious public health concern, the current culture-dependent detecting methods using nutrient-rich conditions may not be suitable for evaluating microbial risk. In the present study, a novel cultivation method was developed to detect antibiotic-resistant microbes at various nutrient levels. A nutrient-rich medium Luria-Bertani broth (LB) was diluted at a wide range of dilution factors (10(0)-10(4)) and amended with either tetracycline or vancomycin. A standard environmental cultivation medium, R2A, was also used by amending with antibiotics. The diluted LB with antibiotics was able to detect previously known oligotrophic and antibiotic-resistant bacteria in drinking water and swine manure samples, respectively. These results validate the capability of the new method to detect antibiotic-resistant microbes in various environmental water samples. Using the developed method in assessing microbial risk due to antibiotic-resistant microbes in river and municipal wastewater plants, we found that the viable counts and antibiotic resistance fraction were significantly influenced by the type and concentration level of antibiotic exposure and the cultivation medium conditions. This suggests a further need to standardize cultivation method procedures, to assess microbial risk in water samples.

A highly potent inhibitor of cathepsin K (relacatib) reduces biomarkers of bone resorption both in vitro and in an acute model of elevated bone turnover in vivo in monkeys

Cathepsin K is an osteoclast-derived cysteine protease that has been implicated as playing a major role in bone resorption. A substantial body of evidence indicates that cathepsin K is critical in osteoclast-mediated bone resorption and suggests that its pharmacological inhibition should result in inhibition of bone resorption in vivo. Here we report the pharmacological characterization of SB-462795 (relacatib) as a potent and orally bioavailable small molecule inhibitor of cathepsin K that inhibits bone resorption both in vitro in human tissue and in vivo in cynomolgus monkeys. SB-462795 is a potent inhibitor of human cathepsins K, L, and V (K(i, app)=41, 68, and 53 pM, respectively) that exhibits 39-300-fold selectivity over other cathepsins. SB-462795 inhibited endogenous cathepsin K in situ in human osteoclasts and human osteoclast-mediated bone resorption with IC50 values of approximately 45 nM and approximately 70 nM, respectively. The anti-resorptive potential of SB-462795 was evaluated in normal as well as medically ovariectomized (Ovx) female cynomolgus monkeys. Serum levels of the C- and N-terminal telopeptides of Type I collagen (CTx and NTx, respectively) and urinary levels of NTx were monitored as biomarkers of bone resorption. Administration of SB-462795 to medically ovariectomized or normal monkeys resulted in an acute reduction in both serum and urinary markers of bone resorption within 1.5 h after dosing, and this effect lasted up to 48 h depending on the dose administered. Our data indicate that SB-462795 potently inhibits human cathepsin K in osteoclasts, resulting in a rapid inhibition of bone resorption both in vitro and in vivo in the monkey. These studies also demonstrate the therapeutic potential of relacatib in the treatment of postmenopausal osteoporosis and serves to model the planned clinical trials in human subjects.

Multi-array antibody screening in detecting antibodies to mismatched HLA in patients awaiting a second transplant

Effective identification of HLA specificities to which a prospective transplant recipient has antibodies depends on how effective the most sensitive assay is in detecting these antibodies. To ascertain the assay's efficacy, the results of antibody screening of patients on the waiting list for a second transplant were studied. A commercially available panel of fluoro-coded microbeads coated with multiple and single purified class I or II HLA antigens was used with flow cytometry to detect antibodies in human serum (LABScreen, One Lambda, Canoga Park, Calif, USA). A total of 112 HLA-A, B, and DR mismatches between donors and recipients were present among 34 patients. Antibodies to 56% of the mismatches were detected with 67% of the HLA-A, 38% of the HLA-B, and 63% of the HLA-DR mismatches detected, respectively. Thirty percent of the patients had antibodies to all of the mismatched HLA, 43% had antibodies to some, and 27% did not develop antibodies to any of the mismatched antigens. Among patients who developed antibodies to all of the mismatched HLA, 60% had had a transplant nephrectomy. Only 11% of patients who had no antibodies detected to mismatched HLA had had a transplant nephrectomy and 44% of them were still on immunosuppression. Using the Matchmaker program developed by Duquesnoy, the latter group of patients had a sufficient number of triplet mismatches that could have resulted in an antibody response. All of the undetected antibodies had been identified in other patients in this group. The assay used in this study to detect antibodies is considered the most sensitive one available. Nonetheless, antibodies to slightly less than half of the mismatched HLA antigens were not detected. It appears that the assay system is capable of detecting the antibodies, since in other patients with the same mismatched HLA, antibodies were detected. It is likely that the recipients could develop antibodies since there was a sufficient degree of disparity in the HLA of donors and recipients. Antibodies were more likely to be detected when there had been a transplant nephrectomy and the absence of immunosuppression. There was no way of knowing whether we were missing detecting antibodies or if they were not present. The results of this study have important implications with respect to utilizing "unacceptable antigens" in an allocation system for patients awaiting a second transplant.