Melatonin reduced volume of cerebral infarct induced by photothrombosis in wild-type mice, not in Cyclooxygenase-1 gene knockout mice

Cyclooxygenase (COX) is crucial in inflammation and plays important role in cerebral ischemia. Antiinflammatory effects of melatonin have been verified in previous studies. In this study, cerebral blood flow (CBF) was monitored during operation, infarct volume (IFV) was determined with 5-triphenyltetrazolium chloride (TTC) staining and MR image, and neurological functions were evaluated with turn in an alley and fall pole test in both COX1-gene knockout and wide-type mice with or without melatonin administration 3 days after photothrombosis. CBF reduction, IFV and neurological deficits were not significantly different in COX-1 wild-type and COX-1 knockout mice. Melatonin (15 mg/kg) intraperitoneal injection decreased the CBF reduction, IFV and the latency to turn in an alley in COX-1 wide-type mice, whereas the neuroprotective effect of melatonin was attenuated in COX-1 knockout mice. We concluded that melatonin reduced susceptibility to photothrombotic stroke. COX-1 gene knockout does not alter the susceptibility to cerebral ischemia caused by photothrombosis. COX-1 plays an important role in the pathway of the protection of melatonin.

Significance of HIF-1-active cells in angiogenesis and radioresistance

Human solid tumors contain hypoxic regions that have considerably lower oxygen tension than the normal tissues. Hypoxia offers resistance to radiotherapy and anticancer chemotherapy, as well as predispose to increased tumor metastases. Furthermore, hypoxia induces hypoxia-inducible factor-1 (HIF-1), which in turn increases tumor angiogenesis. Thus, eradication of HIF-1-active/hypoxic tumor cells is very important for cancer therapy. We have previously reported that procaspase-3 fused with a von Hippel-Lindau (VHL)-mediated protein destruction motif of alpha subunit of HIF-1 (HIF-1alpha) containing Pro564, named TAT-ODD-procaspase-3 (TOP3), specifically induced cell death to hypoxic cells in vivo as well as in vitro. We now report that TOP3 also eradicates the radiation-induced HIF-1-active tumor cells. HIF-1 activity in the xenografts of human tumor cells, which express luciferase under the transcriptional control of HIF-1, were monitored and quantified daily with an in vivo bioluminescence photon-counting device. HIF-1 activity in tumors was more rapidly increased by ionizing radiation (IR) compared to untreated tumors. TOP3 efficiently decreased the HIF-1-activity in irradiated tumors as well as unirradiated ones, indicating TOP3 eradicated tumor cells with HIF-1-activity induced by IR as well as hypoxia. Eradication of HIF-1-active/hypoxic cells in the xenografts during irradiation exhibited significant suppression in angiogenesis and strong enhancement in a long-term growth suppression of tumor xenografts. These results further strengthen the argument that HIF-1-active/hypoxic cells play crucial roles in angiogenesis and radioresistance.

Genetic polymorphisms involved in toxicant-metabolizing enzymes and the risk of chronic benzene poisoning in Chinese occupationally exposed populations

Benzene is a recognized haematotoxin and leukaemogen, but its mechanism of action and the role of genetic susceptibility are still unclear. Cytochrome P450 2E1 (CYP2E1) and myeloperoxidase (MPO) are involved in benzene activation; and NAD (P)H:quinine oxidoreductase 1 (NQO1), glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase mu 1 (GSTM1) participate in benzene detoxification. The common, well-studied single-nucleotide polymorphisms (SNPs) were analysed in these genes drawn from the toxicant-metabolizing pathways. A total of 100 workers with chronic benzene poisoning (CBP) and 90 controls were enrolled in China. There was a 2.82-fold (95% CI = 1.42-5.58) increased risk of CBP in the subjects with the NQO1 609C > T mutation genotype (T/T) compared with those carrying heterozygous (C/T) and wild-type (C/C). The subjects with the GSTT1 null genotype had a 1.91-fold (95% CI = 1.05-3.45) increased risk of CBP compared with those with GSTT1 non-null genotype. There was no association of CYP2E1 and MPO genotype with CBP. A three genes' interaction showed that there was a 20.41-fold (95% CI = 3.79-111.11) increased risk of CBP in subjects with the NQO1 609C > T T/T genotype and with the GSTT1 null genotype and the GSTM1 null genotype compared with those carrying the NQO1 609C > T C/T and C/C genotype, GSTT1 non-null genotype, and GSTM1 non-null genotype. The study provides evidence of an association of a gene-gene interaction with the risk of CBP.

Human ovarian tumour-derived chaperone-rich cell lysate (CRCL) elicits T cell responses in vitro

Tumour-derived chaperone-rich cell lysate (CRCL), which is made up of numerous heat shock proteins, has been used successfully to generate tumour-specific T cell responses and protective immunity against a wide range of murine tumours. In this study, we have investigated the potency of human ovarian cancer-derived CRCL to activate dendritic cells (DC) and to generate tumour-specific T cells in vitro. CRCL was generated from primary ovarian cancers and SKOV3-A2, a HER2/neu, Wilm's tumour gene 1 (WT1) and human leucocyte antigen (HLA)-A2 positive human ovarian tumour cell line. Peripheral blood mononuclear cells from both HLA-A2(+) healthy donors and HLA-A2(+) ovarian cancer patients were stimulated weekly with autologous DC loaded with ovarian tumour-derived CRCL. After four to six stimulations in vitro, specific cytokine secretion and cytotoxicity were measured. CRCL promoted interleukin (IL)-12 secretion and enhanced the immunostimulatory capacity of DC. T cells from healthy controls and from ovarian cancer patients secreted higher amounts of interferon-gamma following in vitro restimulation with ovarian cancer-derived CRCL than with HER2/neu or WT1 peptide-pulsed DC. We were also able to generate cytotoxic T lymphocyte activity against cancer-specific antigens such as HER2/neu and WT1 from all healthy donors, but from only one of the four ovarian cancer patients with bulky disease. These preliminary results substantiate further the concept that CRCL may prove to be a potent adjuvant for women suffering from ovarian cancer and that this personalized vaccine may be a promising approach for active immunotherapy.

S100A1: a powerful marker to differentiate chromophobe renal cell carcinoma from renal oncocytoma

AIMS

The common subtypes of renal tumours are conventional, papillary, chromophobe carcinoma and oncocytoma. The morphological differentiation between chromophobe carcinoma and oncocytoma may be difficult. The aim was to evaluate S100A1 as a new marker for the differentiation of the two subtypes.

METHODS AND RESULTS

Thirty-nine tumour samples [nine clear cell renal cell carcinomas (RCCs), six papillary RCCs, nine chromophobe RCCs and 15 oncocytomas] were studied. The protein expression of S100A1 was evaluated by immunohistochemistry. The gene expression of S100A1 was analysed by reverse transcriptase-polymerase chain reaction. Nine oncocytomas showed strong immunoreactivity for S100A1. Four oncocytomas were scored as moderate and one as weak reactivity. In total, 14/15 (93%) of oncocytomas were considered to be immunopositive. In contrast, all nine chromophobe RCCs were considered to be immunonegative. There was a significant difference in the positive percentages of staining of S100A1 between these two subtypes (P < 0.01). S100A1 immunoreactivity was observed in 6/9 clear cell and 4/6 papillary carcinomas. The results of S100A1 gene expression corresponded well with the results of immunohistochemistry.

CONCLUSION

S100A1 may be a potentially powerful marker to differentiate the chromophobe RCC from renal oncocytoma.

Shear waves induced by moving needle in MR elastography

Magnetic resonance elastography (MRE) is a phase contrast-based method for observing shear wave propagation in a material to determine its stiffness. The objective of this study was to determine whether shear waves suitable for MRE could be induced using a moving acupuncture needle. Tissue-simulating bovine gel phantom and a 0.4 mm diameter acupuncture needle were used in the experiment. The results showed that observable shear waves could be induced in the gel phantom by cyclic needle motion. The observed wavelength varied with excitation frequency, as expected. Generating shear waves using moving needles may be a useful tool to study the basic mechanism of acupuncture with MRE. Further study will be conducted to observe the wave motion in inhomogeneous media and acupuncture-induced effects in in-vivo studies.

Ligands of peroxisome proliferator-activated receptor inhibit homocysteine-induced DNA methylation of inducible nitric oxide synthase gene

Homocysteine (Hcy) is a risk factor for atherosclerosis. It is generally accepted that inducible nitric oxide synthase (iNOS) is a key enzyme in the regulation of vascular disease. The aim of the present study is to investigate the effects of peroxisome proliferator-activated receptor ligands on iNOS in the presence of Hcy in human monocytes. Foam cells, induced by oxidize low density lipoprotein (ox-LDL) and phorbol myristate acetate (PMA) in the presence of different concentrations of Hcy, clofibrate and pioglitazone in human monocytes for 4 d, were examined by oil red O staining. The activity of iNOS was detected by real-time quantitative reverse transcription-polymerase chain reaction and Western blot analysis. The capability of DNA methylation was measured by assaying endogenous C5 DNA methyltransferase (C5MTase) activity, and the iNOS promoter methylation level was determined by quantitative MethyLight assays. The results indicated that Hcy increased the activity of C5MTase and the level of iNOS gene DNA methylation, resulting in a decrease of iNOS expression. Clofibrate and pioglitazone could antagonize the hcy effect on iNOS expression through DNA methylation, resulting in attenuation of iNOS transcription. These findings suggested that Hcy decreased the expression of iNOS by elevating iNOS DNA methylation levels, which can repress the transcription of some genes. Peroxisome proliferator-activated receptor alpha/gamma ligands can down-regulate iNOS DNA methylation, and could be useful for preventing Hcy-induced atherosclerosis by repressing iNOS expression.

Detection of proximal caries with high-resolution and standard resolution digital radiographic systems

AIMS

The aim of this study was to: (1) compare the diagnostic accuracy of the high-resolution and standard resolution settings of four digital imaging systems for caries diagnosis and (2) compare the effect on the diagnostic accuracy of reducing the high-resolution image sizes to the standard resolution dimensions, and vice versa.

MATERIALS AND METHODS

90 extracted human premolars were mounted in groups of 5 in plaster blocks, containing 4 test teeth and 1 non-test tooth. Two blocks at a time were placed in a jig to simulate a bitewing radiograph. Radiographs were taken using four digital systems (Planmeca Dixi 2; Gendex Visualix HDI; Dürr Vistascan; Digora Optime), each at two resolution settings. Next, the teeth were sectioned and a total of 65 surfaces were incorporated in the study. Additionally, the bicubic interpolation method was applied to reduce the high-resolution original images and to enlarge the standard resolution images. The original, reduced and enlarged images were randomly shown to five observers in two random sessions. The observers were asked to assess caries depth on a 4-point scale. The observers' scores were compared with the results from a histological examination. Data were analysed using the statistical theory for multivariate discrete data. Cohen's kappa was used to determine the agreement with the gold standard.

RESULTS

None of the comparisons between the spatial resolution settings, or the comparisons between increased or reduced image size and the original image sizes, showed significant differences in the probability of caries detection (chi2=26.59, df=26, P approximately 0.50). The four digital systems used in this study differ significantly in the probability of caries detection (chi2=41.55, df=24, P<0.02). Compared with the gold standard, the Gendex Visualix HDI CCD sensor has the highest measure of agreement (kappa=0.31).

CONCLUSION

Caries diagnosis does not improve when using high-resolution settings compared with the standard settings. The use of bicubic convolution interpolation for zooming has no detectable effect on caries diagnosis and therefore is recommended to use when enlarging or reducing radiographs. The probability of caries detection, however, was different for the sensor systems of the different manufacturers.

Detection of Proximal Caries in vitro Using Standard and Task-Specific Enhanced Images from a Storage Phosphor Plate System

Eight dentists evaluated 72 proximal surfaces of premolars with respect to all caries lesions and to lesions into dentine in digital images from a storage phosphor plate system. The images were processed in four different ways: (1) the default algorithm of the standard imaging system (DF); (2) an algorithm correcting for attenuation and visual response (AV), and two proprietary caries-specific enhancement algorithms (3) K1, and (4) K2, respectively. The lesions were validated by histological examination. There were no significant differences in the areas under the receiver operating characteristic curves between differently processed radiographs for the categories of all caries lesions and caries into dentine.

Analysis of alpha-fetoprotein mRNA level on the tumor cell hematogenous spread of patients with hepatocellular carcinoma undergoing orthotopic liver transplantation

The aim of this study was to detect alpha-fetoprotein (AFP) mRNA levels in the preoperative and intraoperative peripheral blood of patients with hepatocellular carcinoma (HCC) receiving orthotopic liver transplantation (OLT).

METHODS

We detected AFP mRNA by TaqMan real-time reverse transcriptase-polymerase chain reactions (RT-PCR) on the peripheral blood cells (PBCs) from 30 HCC patients undergoing OLT.

RESULTS

In RT-PCR, fluorescence was undetectable in any control. The positive expression rate of AFP mRNA was 23% (7 of 30) in PBC samples of OLT patients preoperatively and 50% (15 of 30) just before hepatectomy during the operation. The positive rate of AFP mRNA in OLT patients at this time was higher than that at preoperation, a difference that was statistically significant (P < .01).

CONCLUSION

The OLT operation induced release of cells from the liver into the peripheral blood circulation. This may be an important mechanism of liver cancer cell dissemination deserving further investigation.

Emergence of VanD-type vancomycin-resistant Enterococcus faecium in Stockholm, Sweden

A vancomycin-resistant Enterococcus faecium isolate from the urine of a liver transplant patient in Stockholm was found to contain a vanD gene. The sequence of the vanD PCR product shared 100% identity with the vanD5 allele. The isolate was resistant to a relatively high level of vancomycin (128 mg/L) and a low level of teicoplanin (4 mg/L). This is the first VanD-type vancomycin-resistant E. faecium isolate reported in Sweden. The emergence of this strain reinforces the necessity of infection control efforts to interrupt the spread of these organisms.

Association of tightly locked occlusion with temporomandibular disorders

The association between teeth loss and temporomandibular disorders (TMD) is still inconclusive. A kind of secondary changes of the occlusion after teeth lose called the tightly locked occlusion (TLO), defined as the occluding contact that delivers angled occlusal force on the drifted neighbour and/or the tipped antagonists of the lost posterior teeth, was hypothesized to be association with TMD. The study aimed at investigating the association between the TLO and TMD. A total of 113 posterior-teeth losing patients, 64 with TMD symptoms (group of TMD) and 49 without (group of TMD-Free) were included. Study casts and joint radiographs were made to diagnose the TLO and joint morphological changes. The simultaneous contribution of the potential variables of gender, age, tooth losing number, the TLO, joint symmetry and signs of osteoarthrosis shown on radiographs were tested through binary logistic regression analysis. In women, the TLO entered into logistic model, and had an effect on the incidence of TMD (P = 0.008). The odds ratio of with-TLO versus without-TLO is 2.6 (95% CI: 1.2, 5.8) after controlling for the effect of gender. Age, tooth lose number, joint asymmetry or osseous changes had no effect on the incidence of TMD. The tightly locked occlusion is associated with some signs and symptoms of TMD. Randomized controlled trials will be needed in further studies to test the hypothesis that treatment of a TLO, as defined in the present study, will have a beneficial effect on the signs and symptoms of TMD.

Study on the error in the dynamic spectrum method relative with the pathlength factor as a function of wavelength

Utilizing near-infrared spectroscopy for non-invasive blood component concentration sensing has been a focusing topic in biomedical optics applications. The ease of use, low cost and portability of these methods is a clear advantage over the invasive blood component concentration sensing which is the main sensing method in the clinic application. However, there is no report about any successful non-invasive blood components (except the artery blood oxygen saturation) concentration detection techniques that can meet the requirements of clinic application. One of the most key difficulties is the influence of the individual discrepancy. Dynamic spectrum (DS) is a new measure method of non-invasive blood components concentration sensing presented recently. It can eliminate the individual discrepancy of the tissues except the pulsatile component of the artery blood (PCAB) theoretically. This indicates a brand new way to measure the blood components concentration and a potential to provide absolute quantitation of hemodynamic variables. One of the systematic errors in the calculation of the component changes from NIRS data of the dynamic spectrum is the absolute magnitudes and relative differences in pathlength factors as a function of wavelength. Monte Carlo simulations are used in this paper to examine the importance and mitigation methods of this error while the photoelectric pulse wave is detected on the finger tip. We found wavelength selection to be important variables in minimizing such errors, and replacing the average pathlength factor with the subsection pathlength factor appropriately could reduce the error to a small fraction (10%).

BH3-only proteins in tumorigenesis and malignant melanoma

BH3-only proteins are a subset of the Bcl-2 family of apoptotic regulators. BH3-only proteins function as 'damage sensors' in the cell; they are activated in response to cellular stress or DNA damage, whereupon they initiate apoptosis. Apoptosis is the primary mechanism by which the body rids itself of genetically defective cells and is critical for preventing the accumulation of cells with tumorigenic potential. Therefore, dysregulation of BH3-only proteins may promote tumorigenesis. Furthermore, functional apoptosis pathways are required for the success of most cancer treatments, including chemotherapy. Resistance to chemotherapy, as seen with malignant melanoma, often reflects an inability of tumor cells to undergo apoptosis. By deciphering the roles of BH3-only proteins in tumorigenesis, we may learn how to manipulate cell death pathways to overcome apoptotic resistance. This review summarizes the current knowledge of BH3-only proteins and how they contribute to tumorigenesis, with particular attention given to studies involving melanoma.

Is the dementia rate increasing in Beijing? Prevalence and incidence of dementia 10 years later in an urban elderly population

OBJECTIVE

To examine the time trend of dementia morbidity over the past decade in Beijing, China.

METHOD

In 1997, 1593 community-dwelling elderly aged 60+ years were examined and followed-up over 2-years to identify incident dementia. A similar cohort study of dementia conducted in the same district 10 years prior was used as historical comparison to examine the time trend of dementia incidence.

RESULTS

Forty prevalent dementia cases were identified at the initial examination for a prevalence of 2.51% (95% CI: 1.74-3.28) and 25 incident cases were identified at the follow-up visit for an incidence of 0.90% (0.55-1.25) among residents aged 60+ years. Alzheimer's dementia (AD) was the most common type of dementia in both prevalent and incident cases.

CONCLUSION

The prevalence and incidence rates of dementia in Beijing were slightly higher than those 10 years ago, which was partly because of population aging. AD became the most common subtype of dementia.

Marginal bone levels measured in film and digital radiographs corrected for attenuation and visual response: anin vivostudy

OBJECTIVE

To compare the accuracy and precision of measurements on marginal bone levels in differently processed digital radiographs and in film-based radiographs.

METHODS

Twenty-one patients with a diagnosis of chronic periodontitis were included in this study. Periapical radiographs were exposed with the Dixi digital intraoral radiographic system (Planmeca Oy, Helsinki, Finland) and the F-speed Film (Insight, Eastman-Kodak Co., Rochester, NY), respectively. Digital radiographs were subsequently processed into two sets: (a) correction for attenuation and visual response and (b) the same correction but with an additional shift in grey levels. Patients had periodontal surgery immediately after the radiographs were exposed. The vertical distance from cementoenamel junction to the most apical part of the marginal bone was assessed. The measurements were then employed as reference standard and subtracted by the vertical distance from radiographs accordingly. Altogether, 47 sites were evaluated. Seven observers were employed for evaluation under the same viewing conditions. ANOVA was employed for statistical analysis.

RESULTS

No significant differences were found between the absolute differences of the vertical distance obtained from radiographs to their corresponding reference standards when comparing differently processed digital radiographs, but the absolute differences were significantly smaller in digital radiographs than in films. Interobserver variances were not significant.

CONCLUSION

Digital radiographs have a favourable measurement accuracy compared with film radiographs when assessing marginal bone levels.

In vitro study on influence of a discrete nano-hydroxyapatite on leukemia P388 cell behavior

Influence of a discrete nano-hydroxyapatite crystal (nano-HAp) on lymphatic leukemia P388 cell behavior was investigated by an in vitro technique using an MTT test and FITC analysis. The discrete nano-HAp was prepared by decanting upside clear layer of the nano-HAp suspension which was synthesized by a wet method using calcium hydroxide suspension and phosphoric acid solutions. The nano-HAp was identified as hydroxyapatite by the X-ray powder diffraction pattern and an infrared spectroscopy. The nano-HAp with concentrations of 8-40 microg/ml was dispersed into PRMI 1640 media with leukemia cells derived from BALB/C mice. The survival ratio of the cells decreased with the amounts of the nano-HAp increasing. Apoptosis rates of leukemia P388 cells on co-culturing with the nano-HAp of 35 microg/ml for 24, 48 h were 14.5% and 45.8%, respectively, and higher than those of 10.4% and 34% in controls. The G0/G1 peak values in leukemia P388 cell cycle were declined to reduce and the S peak values increased with extension time of co-culture. These results proved that the discrete nano-HAp can cause apoptosis of the leukemia P388 cells, and selectively act on G1 phase and arrest the G1 phase in cell cycle of the leukemia P388.

The Expression of von Willebrand Factor, Soluble Thrombomodulin, and Soluble P-Selectin During Orthotopic Liver Transplantation

BACKGROUND

We evaluated von Willebrand factor (vWF), soluble thrombomodulin (sTM), and soluble P-selectin (sP-selectin) levels in ischemia/reperfusion injury during orthotopic liver transplantation (OLT).

METHODS

The vWF, sTM, and sP-selectin were analyzed in 20 patients who underwent liver transplantation. Blood samples were drawn from the radial artery at serial times during surgery. Plasma levels of sTM and sP-selectin were detected by enzyme-linked immunosorbent assay (ELISA). The wWF activity was measured using the immuno-turbidimetric method. Plasma aspartate transaminase (AST) and alanine transaminase (ALT) were assayed by routine clinical chemistry testing.

RESULTS

Marked elevation levels of plasma AST and ALT were released during the 15 minutes after reperfusion phase, with a peak on the first postoperative day (P < .01). The sTM level remained unchanged from preoperative to anhepatic phase (P > .05). In contrast, a mean 2.5-fold increase of sTM was observed during the 15-minute reperfusion stage compared with the preoperative value (P < .01). The vWF activity only showed significant increase during the 60-minute reperfusion stage compared with the preoperative value (P < .05). No significant increase occurred in sP-seletin levels during the reperfusion phase. Platelet count showed significant decrease during the entire observation period compared with the preoperative value (P < .01).

CONCLUSION

The endothelial reperfusion injury after OLT is characterized by increased vWF and sTM but not by sP-selectin in peripheral blood.