Roles of Insulin Receptor Substrates (IRS) in renal function and renal hemodynamics.

We have reported previously that renal hemodynamic abnormalities exist in the prediabetic stage of type II diabetic rats. At this prediabetic stage these rats have hyperinsulinemia, insulin resistance and metabolic syndrome. It is well known that insulin resistance is frequently associated with renal abnormalities, but the mechanism underlying this association has remained speculative. Although insulin is known to modify renal hemodynamics, little is known about the roles of insulin receptor substrates (IRS1, IRS2) in the renal actions of insulin. To address this issue, the effects of insulin on renal function and renal hemodynamics were investigated in C57BL/6 (WT: wild type), insulin receptor substrate 1- knockout (IRS1-/-), and IRS2-knockout (IRS2-/-) mice. IRS2-/-mice had elevated glucose level as expected. 24-h urine collections and serum creatinine revealed that creatinine clearance did not significantly differ between these groups. Albuminuria was found in IRS1-/-and IRS2-/-groups. We examined the effects on the IRS during the administration of Losartan, which is widely used for diabetic nephropathy. After the administration of Losartan the IRS displayed improved renal hemodynamics. Moreover, the subjects were also given Pioglitazone, which improves insulin resistance. Losartan significantly reduced albuminuria in both groups. Pioglitazone also showed similar results. We assessed the autoregulatory responses of the total renal blood flow (RBF), the superficial (SBF) and the deep renal cortical blood flow (DBF) with stepwise reductions of renal perfusion pressure (RPP), which was induced by a manual clamp on the abdominal aorta. During the clamp induced reductions of the RPP by 10 to 20mm HG, RBF, SBF and the DBF fell significantly more in the IRS1 and IRS2 than in the WT mice. Furthermore micropuncture studies showded that compared to the WT tubuloglomerular feedback (TGF) responses of the stop flow pressure (Psf) were reduced in both the IRS1 -/- and IRS2 -/-. The results of the IRS1 and IRS2 mice displayed the pressence of hemodynamic abnormalities. Losartan and Pioglitazone have shown the potential to improve these abnormalities. In conclusion the results indicate that IRS plays a major role in the stimulation of renal functions and renal hemodynamics in type type II diabetes.

Defective renal autoregulation in the chronic bile duct ligation model of liver failure.

BACKGROUND: Cirrhosis of the liver is often associated with an impairment of renal function that is usually not associated with consistent structural abnormalities of the renal parenchyma, but is thought to be the functional consequence of arterial underfilling and reduced arterial blood pressure. METHOD: We have used the cirrhosis model of chronic bile duct ligation (BDL) to assess the response of renal blood flow to a change of blood pressure. We have measured renal haemodynamics in BDL rats. RESULT: Three weeks after BDL, rats showed elevated levels of total bilirubin, AST, and ALT as well as reduced arterial blood pressure. Creatinine clearance was significantly reduced, and plasma creatinine and urea nitrogen were elevated. Renal blood flow at baseline blood pressure was significantly lower in the BDL group than in the sham group. Clamp-induced reductions of renal perfusion pressure caused significantly greater changes of renal blood flow in BDL than control rats. The autoregulatory index over a comparable blood pressure range averaged 0.28 ± 0.35 in control rats and 1.26 ± 0.6 in BDL rats (p = 0.0004) indicating impairment of renal autoregulation in liver cirrhosis. CONCLUSION: Tubuloglomerular feedback (TGF) responses were significantly attenuated in BDL rats, especially in the subnormal flow range. Impairment of renal blood flow autoregulation, to some extent mediated by reduced TGF-mediated vasodilatation, may contribute to the renal vascular constrictor state in liver cirrhosis by preventing the full dilatory response to the blood pressure reduction.

Effects of shielding on the induction of 53BP1 foci and micronuclei after Fe ion exposures.

High atomic number and high-energy (HZE) particles in deep space are of low abundance but substantially contribute to the biological effects of space radiation. Shielding is so far the most effective way to partially protect astronauts from these highly penetrating particles. However, simulated calculations and measurements have predicted that secondary particles resulting from the shielding of cosmic rays produce a significant fraction of the total dose and dose equivalent. In this study, we investigated the biological effects of secondary radiation with two cell types, and with cells exposed in different phases of the cell cycle, by comparing the biological effects of a 200 MeV/u iron beam with a shielded beam in which the energy of the iron ion beam was decreased from 500 MeV/u to 200 MeV/u with PMMA, polyethylene (PE), or aluminum. We found that beam shielding resulted in increased induction of 53BP1 foci and micronuclei in a cell-type-dependent manner compared with the unshielded 200 MeV/u Fe ion beam. These findings provide experimental proof that the biological effects of secondary particles resulting from the interaction between HZE particles and shielding materials should be considered in shielding design.

Continuous low-dose irradiation by I-125 seeds induces apoptosis of gastric cancer cells regardless of histological origin.

The efficacy of conventional radiation therapy for gastric cancer is controversial. In this study, we evaluated the in vitro and in vivo effects of continuous low-dose-rate irradiation by I-125 seeds on different histological types of gastric cancer cell lines. Three human gastric cancer cell lines (MKN74, MKN45, and NUGC4) were treated with or without continuous low-dose irradiation by I-125 seeds in vitro and in vivo. Cell viability, apoptosis, caspase-3 assay, and cell-cycle distribution were examined in vitro. Body weight and tumor volumes of BALB/c nude mice bearing MKN74, MKN45, and NUGC4 gastric cancer xenografts were measured, and in vivo cell proliferation and apoptosis assays were performed by Ki67 and TUNEL staining, respectively. Continuous low-dose-rate irradiation by I-125 seeds reduced cell viability and induced cell apoptosis through the activation of caspase-3, and led to the accumulation of cells in the G 2/M phase in vitro. It also suppressed the growth of gastric cancer xenografts in nude mice, while inhibiting cell proliferation and inducing apoptosis as demonstrated by Ki67 and TUNEL staining. Therefore, our data suggest that continuous low-dose-rate irradiation by I-125 seeds could be a promising new option for gastric cancer treatment, regardless of histological origin.

Thrombotic microangiopathy secondary to steroid pulse therapy administered for refractory nephrotic syndrome.

A 79-year-old woman with familial hyperlipidemia was treated with low-density lipoprotein apheresis. She was hospitalized due to fatigue and edema, and massive proteinuria was discovered. Renal biopsy revealed no distinct abnormalities, thus suggesting a diagnosis of minimal change nephrotic syndrome. She developed acute kidney injury and hemodialysis was initiated. Two series of steroid pulse therapy were given, but the proteinuria did not decrease. Thereafter, she developed thrombocytopenia and fell into a stupor. Thrombotic microangiopathy (TMA) was the most likely diagnosis. Plasma exchange was initiated, resulting in improvements in platelet counts and in her level of consciousness. Clinicians should therefore be aware that TMA can occur as a result of steroid pulse therapy.

Chromosome aberrations in normal human fibroblasts analyzed in G0/G1 and G2/M phases after exposure in G0 to radiation with different linear energy transfer (LET).

We have studied the induction of chromosome aberrations in human fibroblasts exposed in G0/G1 to X-rays or heavy ions to study the influence of G1 cell cycle arrest. Confluent normal fibroblasts were exposed to X-rays or accelerated particles with different LET values and chromosome aberrations were investigated in the first G0/G1 and G2//M phase. The particles used here were 490MeV/nucleon Si, 500MeV/nucleon Fe, and 200MeV/nucleon Fe ions. Cells were subcultured 24h after exposure and premature chromosome condensation (PCC) was performed by fusion-induced method for analysis of G0/G1 cells, and chemically-induced method for analysis of G2 and metaphase cells. Chromosome damage was assessed in chromosomes 1 and 3 using whole chromosome fluorescence in situ hybridization (FISH). Cell cycle was analyzed by flow cytometry at different incubation times following subculture. After irradiation with 2Gy of high-LET particles, the yields of chromosome aberrations and fragments were significantly higher in G0/G1 phase than in G2/M phase, whereas similar yields of damage were measured in both phases after exposure to X-rays. In contrast, the yield of misrepair, assessed by the number of color junctions, was similar in the G0/G1 and G2/M phases after exposure to either X-rays or high-LET particles. The yields of chromosome aberrations, fragments, and color junctions in both the G0/G1 and the G2/M phases, increased with LET up to 200keV/µm, then decreased for 440keV/µm Fe particles. A good correlation was found between chromosome aberrations in both G0/G1 and G2/M cells and survival fractions after 2Gy of different LET radiations, although the slopes were steeper for the G0/G1 cells. Flow cytometry analysis indicated that high-LET particles induce more non cycling G0/G1 cells within 48h of subculture than X-rays, suggesting that chromosome aberrations scored at the G2/M phase may not accurately describe the true radiation effect.

Comparison of the repair of potentially lethal damage after low- and high-LET radiation exposure, assessed from the kinetics and fidelity of chromosome rejoining in normal human fibroblasts.

Potentially lethal damage (PLD) and its repair (PLDR) were studied in confluent human fibroblasts by analyzing the kinetics of chromosome break rejoining after X-ray or heavy-ion exposures. Cells were either held in the non-cycling G0 phase of the cell cycle for 12 h, or forced to proliferate immediately after irradiation. Fusion premature chromosome condensation (PCC) was combined with fluorescence in situ hybridization (FISH) to study chromosomal aberrations in interphase. The culture condition had no impact on the rejoining kinetics of PCC breaks during the 12 h after X-ray or heavy-ion irradiation. However, 12 h after X-ray and silicon irradiation, cycling cells had more chromosome exchanges than non-cycling cells. After 6 Gy X-rays, the yield of exchanges in cycling cells was 2.8 times higher than that in non-cycling cells, and after 2 Gy of 55 keV/µm silicon ions the yield of exchanges in cycling cells was twice that of non-cycling cells. In contrast, after exposure to 2 Gy 200-keV/µm or 440-keV/µm iron ions the yield of exchanges was similar in non-cycling and cycling cells. Since the majority of repair in G0/G1 occurs via the non-homologous end joining process (NHEJ), increased PLDR in X-ray and silicon-ion irradiated cells may result from improved cell cycle-specific rejoining fidelity through the NHEJ pathway, which is not the case in high-LET iron-ion irradiated cells.

Renal disease in the elderly and the very elderly Japanese: analysis of the Japan Renal Biopsy Registry (J-RBR).

BACKGROUND AND OBJECTIVES: Data regarding renal disease in the elderly (age ≥65 years old) and very elderly (age ≥80 years old) Japanese are extremely limited. The aim of this study was to examine the causes of renal disease and their clinical presentations in elderly patients who underwent renal biopsy. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: From July 2007 to November 2011, all of the elderly native renal biopsy patients who had been registered in the Japan Renal Biopsy Registry (J-RBR; 2802 including 1596 males and 1206 females) were identified. Their data were compared with a control group of 7416 patients who ranged in age from 20 to 64 years old and were registered on the J-RBR over the same period. In addition, the clinical and pathological classifications of 276 very elderly patients were also analyzed. RESULTS: The indications for biopsy were nephrotic syndrome (NS) in 36.2 and 50.7 % of the elderly and the very elderly patients, chronic nephritic syndrome in 31.8 and 17.4 %, and acute kidney injury including rapidly progressive glomerulonephritis in 18.6 and 22.5 %, respectively. Primary glomerular disease was the most frequent diagnosis, followed by MPO-ANCA-positive nephritis, IgA nephropathy (IgAN), and diabetic nephropathy. In primary GN including IgAN, membranous nephropathy (MN) was the most frequent histological type, followed by IgAN and minor glomerular abnormalities. A comparison with the control group showed that MN, MPO-ANCA-positive nephritis, and amyloid nephropathy were more common in the elderly (P < 0.001), and IgAN was less common (P < 0.001). As for nephrotic syndrome in the elderly, MN was the most common histological type, followed by minimal change NS, diabetic nephropathy, amyloid nephropathy, and focal segmental glomerulosclerosis. There was a significant discrepancy between the urinary protein/creatinine ratio and daily proteinuria after the 7th decade of life. CONCLUSIONS: Renal biopsy is a valuable diagnostic tool, even in elderly and very elderly Japanese patients. In the future, modified clinical guidelines for elderly renal disease should be developed.

Nuclear disaster after the earthquake and tsunami of March 11.

We would like to explain the effects of radiation on human health and discuss the actual effects of the contamination with radioactive material present in Tokyo. Currently, external exposure doses are within the allowable range in Tokyo and will have no adverse health effects on adults or children. As for internal exposure doses, there will likely be no problems as regards our ordinary dietary intakes. However, hot spots of Cs-134, Sr-90 and others should be monitored further.

AT cells are not radiosensitive for simple chromosomal exchanges at low dose.

Cells deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome) show increased yields of both simple and complex chromosomal aberrations after high doses (>0.5Gy) of ionizing radiation (X-rays or γ-rays), however less is known on how these cells respond at low dose. Previously we had shown that the increased chromosome aberrations in ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex exchanges. The linear dose-response term for simple exchanges was significantly higher in NBS cells compared to wild type cells, but not for AT cells. However, AT cells have a high background level of exchanges compared to wild type or NBS cells that confounds the understanding of low dose responses. To understand the sensitivity differences for high to low doses, chromosomal aberration analysis was first performed at low dose-rates (0.5Gy/d), and results provided further evidence for the lack of sensitivity for exchanges in AT cells below doses of 1Gy. Normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, showed increased numbers of exchanges at a dose of 1Gy and higher, but were similar to wild type cells at 0.5Gy or below. These results were confirmed using siRNA knockdown of ATM. The present study provides evidence that the increased radiation sensitivity of AT cells for chromosomal exchanges found at high dose does not occur at low dose.

A comparison of chromosome repair kinetics in G(0) and G(1) reveals that enhanced repair fidelity under noncycling conditions accounts for increased potentially lethal damage repair.

Potentially lethal damage (PLD) and its repair were studied in confluent human fibroblasts by analyzing the kinetics of chromosome break rejoining and misrejoining in irradiated cells that were either held in noncycling G(0) phase or allowed to enter G(1) phase of the cell cycle immediately after 6 Gy irradiation. Virally mediated premature chromosome condensation (PCC) methods were combined with fluorescence in situ hybridization (FISH) to study chromosomal aberrations in interphase. Flow cytometry revealed that the vast majority of cells had not yet entered S phase 15 h after release from G(0). By this time some 95% of initially produced prematurely condensed chromosome breaks had rejoined, indicating that most repair processes occurred during G(1). The rejoining kinetics of prematurely condensed chromosome breaks was similar for each culture condition. However, under noncycling conditions misrepair peaked at 0.55 exchanges per cell, while under cycling conditions (G(1)) it peaked at 1.1 exchanges per cell. At 12 h postirradiation, complex-type exchanges were sevenfold more abundant for cycling cells (G(1)) than for noncycling cells (G(0)). Since most repair in G(0)/G(1) occurs via the non-homologous end-joining (NHEJ) process, increased PLD repair may result from improved cell cycle-specific rejoining fidelity of the NHEJ pathway.

Dose response of gamma rays and iron nuclei for induction of chromosomal aberrations in normal and repair-deficient cell lines.

We studied the effects of DNA double-strand break (DSB) repair deficiencies on chromosomal aberration frequency using low doses (<1 Gy) of gamma rays and high-energy iron ions (LET = 151 keV/microm). Chromosomal aberrations were measured using the fluorescence whole-chromosome painting technique. The cell lines included fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome) and gliomablastoma cells proficient in or lacking DNA-dependent protein kinase (DNA-PK) activity. The yields of both simple and complex chromosomal aberrations were increased in DSB repair-defective cells compared to normal cells; the increase was more than twofold higher for gamma rays compared to iron nuclei. For gamma-ray-induced aberrations, the ATM- and NBS-defective lines were found to have significantly larger quadratic components compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher only for the NBS cells. For simple and complex aberrations induced by iron nuclei, regression models preferred purely linear and quadratic dose responses, respectively, for each cell line studied. RBEs were reduced relative to normal cells for all of the DSB repair-defective lines, with the DNA-PK-deficient cells found to have RBEs near unity. The large increase in the quadratic dose-response terms in the DSB repair-deficient cell lines points to the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and to minimize aberration formation. The differences found between AT and NBS cells at lower doses suggest important questions about the applicability of observations of radiation sensitivity at high doses to low-dose exposures.

Abnormal autoregulation and tubuloglomerular feedback in prediabetic and diabetic OLETF rats.

The mechanisms underlying the development and prevention of diabetic nephropathy are still not fully understood. In the present study in the Otsuka Long-Evans Tokushima Fatty (OLETF) model of type 2 diabetic rats, we investigated whether renal hemodynamic abnormalities exist and whether they precede the onset of diabetes. Using OLETF rats in both prediabetic and diabetic stages, we assessed autoregulatory responses of total renal blood flow (RBF) and of superficial (SBF) and deep renal cortical (DBF) blood flow to stepwise reductions of renal perfusion pressure (RPP) induced by a manual clamp on the abdominal aorta. During clamp-induced reductions of RPP by 10 or 20 mmHg, RBF fell significantly more in OLETF rats than in lean control [Long-Evans Tokushima Otsuka (LETO)] rats. Whereas SBF showed no significant changes in either OLETF rats or LETO rats during mild clamping, DBF decreased significantly more in OLETF rats than LETO rats. Reduced autoregulatory efficiency in OLETF rats was observed in both prediabetic and diabetic stages. Micropuncture studies showed that tubuloglomerular feedback (TGF) responses of stop flow pressure are reduced in prediabetic (-7.3 vs. -25.7%) as well as in diabetic OLETF rats compared with LETO control rats (-4.4 vs. -18.8%). Renal corticotomy was performed to measure glomerular capillary pressure (Pgc) directly. Pgc of deep cortical glomeruli was higher than superficial glomerular Pgc in both strains of rats, but the difference was especially pronounced in OLETF rats (deep 78 +/- 2 vs. superficial 57 +/- 4 mmHg). This study demonstrates reduced autoregulatory adjustments and impaired TGF efficiency in prediabetic OLETF rats. Thus abnormal RBF regulation precedes the onset of diabetes and is especially pronounced in the deep cortical region.

Susceptible genes and molecular pathways related to heavy ion irradiation in oral squamous cell carcinoma cells.

BACKGROUND AND PURPOSE: Heavy ion beams are high linear energy transfer (LET) radiation characterized by a higher relative biologic effectiveness than low LET radiation. The aim of the current study was to determine the difference of gene expression between heavy ion beams and X-rays in oral squamous cell carcinoma (OSCC)-derived cells. MATERIALS AND METHODS: The OSCC cells were irradiated with accelerated carbon or neon ion irradiation or X-rays using three different doses. We sought to identify genes the expression of which is affected by carbon and neon ion irradiation using Affymetrix GeneChip analysis. The identified genes were analyzed using the Ingenuity Pathway Analysis Tool to investigate the functional network and gene ontology. Changes in mRNA expression in the genes were assessed by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). RESULTS: The microarray analysis identified 84 genes that were modulated by carbon and neon ion irradiation at all doses in OSCC cells. Among the genes, three genes (TGFBR2, SMURF2, and BMP7) and two genes (CCND1 and E2F3), respectively, were found to be involved in the transforming growth factor beta-signaling pathway and cell cycle:G1/S checkpoint regulation pathway. The qRT-PCR data from the five genes after heavy ion irradiation were consistent with the microarray data (P < 0.01). CONCLUSION: Our findings should serve as a basis for global characterization of radiation-regulated genes and pathways in heavy ion-irradiated OSCC.

Anti-tumor effects of water-soluble propolis on a mouse sarcoma cell line in vivo and in vitro.

The honeybee product propolis and its extracts are known to have biological effects such as antibiotic, anti-viral, anti-inflammatory and anti-tumor activities. This study was designed to investigate whether water-soluble propolis (WSP) inhibits tumor growth. The tumor cell line used was mouse sarcoma 180 (S-180), and its growth was determined in vitro and in vivo with exposure to different concentrations of WSP. The effects of WSP on tumor cells in vitro were evaluated by measuring the intracellular uptake of 3H-thymidine. 3H-thymidine uptake was inhibited in accordance with the concentration of WSP. The minimum concentration of WSP necessary for 3H-thymidine uptake inhibition was 1.0 microg/ml and uptake was suppressed to 88% of the level in non-treated cells at this concentration. In an experiment using tumor-bearing mice, oral administration of WSP was begun 24 hours after transplantation of S-180 cells. WSP was administered to the mice 5 times, every other day for 10 days. The doses were 320 mg/kg (10 mg/mouse) or 960 mg/kg (30 mg/mouse) of body weight. All mice were sacrificed 10 days after transplantation, and tumor growth was evaluated. The orally administered WSP significantly inhibited the growth of transplanted tumors (p < 0.05). Furthermore, histological findings revealed a significant reduction in mitotic cells and tumor invasion of the muscular tissue at both dose-levels of WSP.

Effects of single or repeated administrations of methamphetamine on immune response in mice.

The present study aimed to clarify the connection between immune responses and the administration frequency of methamphetamine (MAP) in male and female mice. Male and female ddY mice were given single or multiple (repeated for 10 days) intraperitoneal injections of MAP (5.0 mg/kg/day). The following immune parameters were examined; the number of leukocytes in peripheral blood and the proliferative activity (phytohemagglutinin;PHA, lipopolysaccharide; LPS response) and natural killer (NK) cell activity in splenic lymphocytes. Further, the differences in metabolic function in the spleen in response to MAP (and its metabolite amphetamine) in male and female mice were measured by gas chromatography. The results of the present study were that; 1) single and repeated MAP injections reduced leukocytes; 2) single MAP injection increased the proliferative response of splenic lymphocytes to PHA stimulation in only male mice, but the response to LPS stimulation was slightly increased in both male and female mice; 3) single and repeated MAP injections reduced NK cell activity of splenic lymphocytes, and especially in female mice with 5 injections of MAP; 4) with 10 MAP injections the NK cell activity and leukocytes recovered to the level of controls; and 5) the metabolic activity of MAP was reduced in female mice treated acutely with MAP in comparison to male mice. These results appear to indicate that immune responses to MAP were involved in the different results shown for administration frequency, sex difference and metabolic process of MAP.

Silencing Ku80 using small interfering RNA enhanced radiation sensitivity in vitro and in vivo.

Ku80 is an important component of DNA double-strand break repair, and Ku80 deficiency leads to extreme sensitivity to ionizing radiation. We studied whether radiation therapy combined with Ku80 silencing by small interfering RNA enhances radiation sensitivity in vitro and in vivo. Seven human cancer cell lines were transfected with Ku80 siRNA included in hemagglutinating virus of Japan envelope vector. H1299 cells were implanted into male BALB/C nu/nu nude mice treated with Ku80 siRNA and irradiation. The survival rate of cell lines transfected with Ku80 siRNA decreased by 10% to 26% with 2-Gy irradiation compared with untransfected cell lines. The gamma-H2AX phosphorylation-positive rates of Ku80 siRNA combined treatment 0.5 h after irradiation in A549 cells and 6 h in H1299 cells were significantly higher (77.6%, p=0.033 and 76.7%, p=0.026, respectively), compared with the groups not treated with siRNA. H1299 xenograft tumors treated with combined therapy decreased in volume and re-grew slowly compared with radiation alone. Our results indicate that combined therapy consisting of Ku80 siRNA and irradiation contributes to inhibition of tumor growth and may be a novel strategy for cancer treatment.

Genes and molecular pathways related to radioresistance of oral squamous cell carcinoma cells.

To identify genes associated with radioresistant oral squamous cell carcinoma (OSCC), we compared gene expression signatures between OSCC cell lines exhibiting radioresistance and cells with radiosensitivity after X-ray irradiation in a dose-dependent manner using Affymetrix GeneChip analysis with Human Genome-U133 plus 2.0 GeneChip. The microarray data identified 167 genes that were significantly overexpressed in radioresistant cells after X-ray irradiation. Among the genes identified, 40 were mapped to 3 highly significant genetic networks identified by the Ingenuity Pathway Analysis tool. Gene ontology analysis showed that cancer-related function had the highest significance. The 40 genes included 25 cancer-related genes that formed 1 network and were categorized by function into growth and proliferation, apoptosis, and adhesion. Furthermore, real-time quantitative reverse transcriptase-polymerase chain reaction showed that the mRNA expression levels of the 25 genes were higher in radioresistant cells than in radiosensitive cells in a dose-dependent manner and in a time-dependent manner. Our results suggest that the identified genes help to elucidate the molecular mechanisms of the radioresistance of OSCC and could be radiotherapeutic molecular markers for choosing the appropriate radiotherapy for this disease.

Repair of potentially lethal damage in normal cells and ataxia telangiectasia cells; consideration of non-homologous end-joining.

When cell lines are held in a quiescent state after irradiation, survival rates are greater than those from cells that are stimulated to grow immediately after irradiation. These differences in survival rates correspond to rates of potentially lethal damage repair. The effects of confluent holding recovery after gamma-irradiation were investigated using normal human fibroblasts (AG1522) and ataxia telangiectasia fibroblasts (GM02052). Calyculin-A-induced premature chromosome condensation and fluorescent in situ hybridization were applied to study G2/M chromosomal aberrations. Survival results indicated normal capacity for PLDR in AG1522 cells but that PLDR was extremely compromised in GM02052 cells. The chromosomal aberration frequency decreased when AG1522 cells were allowed to repair for 24-h, whereas 24-hour incubation had little effect on the aberration frequency in GM02052 cells. Since the main mechanism for dsbs repair during G0/G1 phases of the cells cycle involve the non-homologous end-joining (NHEJ) process, our study indicates that for AG1522 cells the NHEJ repair process is more likely to induce accurate chromosome repair under quiescent G0 conditions than proliferating G1 phase, while in GM02052 cells the fidelity of NHEJ is similarly defective at either cell cycle phase. Reduced fidelity of NHEJ may be responsible for PLDR defect and its hyper-radiosensitivity in A-T cells.

Diagnosis of dementia using perfusion SPECT imaging at the patient's initial visit to a cognitive disorder clinic.

PURPOSE: This study was performed to evaluate the diagnostic accuracy of brain perfusion SPECT in patients visiting the cognitive disorder clinic for initial evaluation using 3D-SSP compared with using standard transaxial section. MATERIALS AND METHODS: Standard transaxial section displays and 3D-SSP z-score maps obtained after administration of Tc-99m ECD or I-123 IMP were randomly interpreted in 315 patients who visited initially to the cognitive disorder clinic (age 46-88 years; 162 women, 153 men). Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated and receiver operating characteristic (ROC) analysis was performed. RESULTS: One hundred thirty-seven patients were clinically diagnosed with Alzheimer disease and 178 patients were diagnosed with other disorders and age-associated cognitive decline. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy calculated using standard transaxial display were 61%, 70%, 61%, 70%, and 66%, respectively, and using the 3D-SSP z-score map were 90%, 74%, 73%, 90%, and 81%, respectively. Particularly, the sensitivity value improved in mild cases compared with severe cases using 3D-SSP. Diagnostic performance with 3D-SSP was superior in both mild dementia (Az = 0.64 [section] vs 0.81 [3D-SSP], P = 0.001) and severe dementia (Az = 0.75 [section] vs 0.90 [3D-SSP], P = 0.002). CONCLUSIONS: Brain perfusion SPECT was useful for diagnosis in patients who come to the cognitive disorder clinic for initial evaluation using 3D-SSP.