Cinnamon extract induces tumor cell death through inhibition of NFkappaB and AP1

BACKGROUND

Cinnamomum cassia bark is the outer skin of an evergreen tall tree belonging to the family Lauraceae containing several active components such as essential oils (cinnamic aldehyde and cinnamyl aldehyde), tannin, mucus and carbohydrate. They have various biological functions including anti-oxidant, anti-microbial, anti-inflammation, anti-diabetic and anti-tumor activity. Previously, we have reported that anti-cancer effect of cinnamon extracts is associated with modulation of angiogenesis and effector function of CD8+ T cells. In this study, we further identified that anti-tumor effect of cinnamon extracts is also link with enhanced pro-apoptotic activity by inhibiting the activities NFkappaB and AP1 in mouse melanoma model.

METHODS

Water soluble cinnamon extract was obtained and quality of cinnamon extract was evaluated by HPLC (High Performance Liquid Chromatography) analysis. In this study, we tested anti-tumor activity and elucidated action mechanism of cinnamon extract using various types of tumor cell lines including lymphoma, melanoma, cervix cancer and colorectal cancer in vitro and in vivo mouse melanoma model.

RESULTS

Cinnamon extract strongly inhibited tumor cell proliferation in vitro and induced active cell death of tumor cells by up-regulating pro-apoptotic molecules while inhibiting NFkappaB and AP1 activity and their target genes such as Bcl-2, BcL-xL and survivin. Oral administration of cinnamon extract in melanoma transplantation model significantly inhibited tumor growth with the same mechanism of action observed in vitro.

CONCLUSION

Our study suggests that anti-tumor effect of cinnamon extracts is directly linked with enhanced pro-apoptotic activity and inhibition of NFkappaB and AP1 activities and their target genes in vitro and in vivo mouse melanoma model. Hence, further elucidation of active components of cinnamon extract could lead to development of potent anti-tumor agent or complementary and alternative medicine for the treatment of diverse cancers.

Self-assembled growth of catalyst-free GaN wires by metal-organic vapour phase epitaxy

A catalyst-free method for growing self-assembled GaN wires on c-plane sapphire substrates by metal-organic vapour phase epitaxy is developed. This approach, based on in situ deposition of a thin SiN(x) layer (approximately 2 nm), enables epitaxial growth of c-oriented wires with 200-1500 nm diameters and a large length/diameter ratio (>100) on c-plane sapphire substrate. Detailed study of the growth mechanisms shows that a combination of key parameters is necessary to obtain vertical growth. In particular, the duration of the SiN(x) deposition prior to the wire growth is critical for controlling the epitaxy with the substrate. The GaN seed nucleation time determines the mean size diameter and structural quality, and a high Si-dopant concentration promotes vertical growth. Such GaN wires exhibit UV-light emission centred at approximately 350 nm and a weak yellow band (approximately 550 nm) at low temperature.

Syndecan-2 regulates cell migration in colon cancer cells through Tiam1-mediated Rac activation

Expression of the cell surface adhesion receptor syndecan-2 is known to be involved in the regulation of cancer cell migration. However, the molecular mechanism of syndecan-2-mediated cell migration remains unknown. Here we report that Rac contributes to the regulation of syndecan-2-mediated cancer cell migration. Overexpression of syndecan-2 enhanced migration and invasion of human colon adenocarcinoma cells Caco-2 and HCT116 cells. In parallel with the increased cell migration/invasion, syndecan-2 overexpression enhanced Rac activity, while dominant negative Rac (RacN17) diminished syndecan-2-mediated increased cancer cell migration. In addition syndecan-2 expression increased membrane localization of Tiam1 and syndecan-2-mediated cell migration/invasion of Caco-2 cells was diminished when Tiam1 levels were knocked-down with small inhibitory RNAs. Furthermore, oligomerization-defective syndecan-2 mutants failed to increase membrane localization of Tiam1, activation of Rac and subsequent cell migration of both Caco-2 and HCT116 cells. Taken together, these results suggest that syndecan-2 regulates cell migration of colon carcinoma cells through Tiam1-dependent Rac activation in colon cancer cells.

Induction of glioma apoptosis by microglia-secreted molecules: The role of nitric oxide and cathepsin B

Microglia contributes significantly to brain tumor mass, particularly in astrocytic gliomas. Here, we examine the cytotoxic effects of soluble components secreted from microglia culture on glioma cells. Microglia conditioned culture medium (MCM) actively stimulated apoptotic death of glioma cells, and the effects of MCM prepared from LPS- or IFN-gamma-activated microglia were more pronounced. The cytotoxic effects were glioma-specific in that primary cultured rat astrocytes were not affected by MCM. A donor of peroxynitrite induced glioma-specific cell death. In addition, NO synthase inhibitor suppressed glioma cell death induced by activated MCM, indicating that NO is one of the key molecules responsible for glioma cytotoxicity mediated by activated MCM. However, since unstimulated resting microglia produces low or very limited level of NO, MCM may contain other critical molecule(s) that induce glioma apoptosis. To identify the proteins secreted in MCM, proteomic analysis was performed on control or activated medium. Among over 200 protein spots detected by Coomassie blue staining, we identified 26 constitutive and 28 LPS- or IFN-gamma-regulated MCM proteins. Several cathepsin proteases were markedly expressed, which were reduced upon activation. In particular, suppression of cathepsin B by the chemical inhibitors significantly reversed MCM-induced glioma cell death, implying a critical role of this protease in cytotoxicity. Our findings provide evidence on the functional implications of specific microglial-secreted proteins in glioma cytotoxicity, as well as a basis to develop a proteomic databank of both basal and activation-related proteins in microglia.

Coarsening kinetics of a spinodally decomposed vicinal Si(111) surface

The coarsening kinetics of the stepped-and-terrace groove structure formed on a vicinal Si(111) surface was investigated by in-situ synchrotron x-ray scattering. The time evolution of the groove period L at various temperatures below the (1 x 1)-to-(7 x 7) transition falls onto a universal curve when the annealing time is scaled by a scale factor. Distinctive stages of spinodal decomposition, coarsening, and saturation are identified in the evolution of the groove period. L increases following a power law, L approximately t;{n} with n = 1/6 and 0.29 in the initial stage and the late stage of coarsening, respectively. The initial coarsening proceeds via collective motion of step bunches while the late stage is dominated by the diffusion of individual steps.

Cinnamon extract suppresses tumor progression by modulating angiogenesis and the effector function of CD8+ T cells

Cinnamon is one of the most widely used herbal medicines with diverse bioactive effects. However, little evidence has been reported about the potential anti-tumor effects of cinnamon. In vitro and in vivo system, cinnamon treatment strongly inhibited the expression of pro-angiogenic factors and master regulators of tumor progression not only in melanoma cell lines but also in experimental melanoma model. In addition, cinnamon treatment increased the anti-tumor activities of CD8(+) T cells by increasing the levels of cytolytic molecules and their cytotoxic activity. In conclusion, cinnamon extract has the potential to be an alternative medicine for tumor treatment.

The effects of strontium ranelate in Asian women with postmenopausal osteoporosis

The aim of this study was to assess the efficacy and safety of strontium ranelate in the treatment of postmenopausal women with osteoporosis in Taiwan. In this 12-month multicenter, randomized, double-blind, placebo-controlled study, 125 women with osteoporosis were randomly given either strontium ranelate 2 g daily or placebo. Lumbar spine, femoral neck, and total-hip bone mineral density (BMD) and biochemical markers of bone turnover were measured; adverse events and tolerability were recorded and assessed. Subjects treated with strontium ranelate showed significant increases in BMD of 5.9% at the lumbar spine, 2.6% at the femoral neck, and 2.7% at the total hip, while the placebo group exhibited no significant change at 12 months. Serum level of a formation marker (bone-specific alkaline phosphatase) was also significantly increased at 6 and 12 months. Thus, although the sample size and the treatment duration of this study could not show its effect of reducing osteoprotic fractures, strontium ranelate showed bone protection effects by increasing BMD and concentrations of a bone formation marker. Safety assessment revealed adverse events were mild and not significantly different from placebo.

Identification and characterization of single nucleotide polymorphisms of SLC22A11 (hOAT4) in Korean women osteoporosis patients

Single nucleotide polymorphisms (SNPs) are the most common form of human genetic variation. Non-synonymous SNPs (nsSNPs) change an amino acid. Organic anion transporters (OATs) play an important role in eliminating or reabsorbing endogenous and exogenous organic anionic compounds. Among OATs, hOAT4 mediates high affinity transport of estrone sulfate and dehydroepiandrosterone sulfate. The rapid bone loss that occurs in post-menopausal women is mainly due to a net decrease of estrogen. In the present study we searched for SNPs within the exon regions of hOAT4 in Korean women osteoporosis patients. Fifty healthy subjects and 50 subjects with osteoporosis were screened for genetic polymorphism in the coding region of SLC22A11 (hOAT4) using GC-clamp PCR and denaturing gradient gel electrophoresis (DGGE). We found three SNPs in the hOAT4 gene. Two were in the osteoporosis group (C483A and G832A) and one in the normal group (C847T). One of the SNPs, G832A, is an nsSNP that changes the 278th amino acid from glutamic acid to lysine (E278K). Uptake of [3H] estrone sulfate by oocytes injected with the hOAT4 E278K mutant was reduced compared with wild-type hOAT4. Km values for wild type and E278K were 0.7 microM and 1.2 microM, and Vmax values were 1.8 and 0.47 pmol/oocyte/h, respectively. The present study demonstrates that hOAT4 variants can causing inter-individual variation in anionic drug uptake and, therefore, could be used as markers for certain diseases including osteoporosis.

Fabrication of one-dimensional devices by a combination of AC dielectrophoresis and electrochemical deposition

We demonstrate a hybrid process for fabricating one-dimensional wire devices. The process is a combination of an alignment procedure using dielectrophoresis and subsequent contact metal formation utilizing electrochemical deposition with non-toxic organic-based Au electrolytes. Several devices have been successfully made from GaN nanowires or multi-walled carbon nanotubes (MWCNTs) using our hybrid technique. We demonstrate that rapid thermal annealing improves the ohmic characteristics by five orders of magnitude in the case of the GaN devices and ∼300% in the case of the MWCNT devices. One of the reasons for this improvement is enhanced gold wetting due to the reduction of grain size at the annealing temperature.

C6 glioma cell insoluble matrix components enhance interferon-gamma-stimulated inducible nitric-oxide synthase/nitric oxide production in BV2 microglial cells

Microglia are the primary central nervous system immune effector cells. Microglial activation is linked to interactions with extracellular cytokines and the extracellular matrix (ECM). Astrocytomas are characterized by their diffuse nature, which is regulated by insoluble ECM components produced by the tumor cells that are largely absent from normal central nervous system tissue. The present study examined the influence of astrocytoma (C6 rat glioma) insoluble matrix components on interferon-gamma (IFN-gamma)-mediated inducible nitric-oxide synthase (iNOS) induction in microglial cells. We found that IFN-gamma-stimulated iNOS induction and nitric oxide release was greater in microglia cultured on C6 glioma cell-derived matrices compared with microglia cultured on primary rat astrocyte-derived matrices. Culture of microglia on C6 glioma cell-derived matrices also led to activation of STAT1, augmentation of IFN-gamma-induced STAT-3 activation, and an increase in IFN-gamma-activated site (GAS)-luciferase reporter activity. In addition, culture of microglia on C6 glioma cell-derived matrices activated NF-kappaB DNA binding activity and transcriptional activity. The results suggest that insoluble matrix components derived from malignant glioma cells can regulate microglia activation. These factors may include ECM components, such as fibronectin, collagen, laminin, vitronectin, and other nondiffusible compounds, and laminin seems to a critical regulator of this process. Microglia activation and subsequent brain inflammation may influence tumor growth, treatment, and metastasis. Better understanding of the regulation of microglial activation by astrocytoma-derived insoluble matrix components may be important in the development of immune-based treatment strategies against malignant brain tumors.

Ionising radiation induces changes associated with epithelial-mesenchymal transdifferentiation and increased cell motility of A549 lung epithelial cells

Radiotherapy remains a major therapeutic option for patients with advanced lung cancer. Nevertheless, the effects of irradiation on malignant biological behaviours (e.g. migration and transformation of cancer cells) have yet to be clarified. We conducted an in vitro study to investigate the radiation-induced alterations including morphology, adhesion, and cell motility of A549 human lung cancer cells. These changes, which are associated with epithelial-mesenchymal transdifferentiation (EMT), seem to be linked to radiation-induced fibrosis, which represents one of the most common long-term adverse effects of curative radiotherapy. In addition, loss of intercellular adhesion and increased cell motility may be involved in post-radiotherapy-associated metastasis. We showed that stress fibres and focal adhesions are increased and that cell-cell junctions are decreased in response to ionising radiation. Radiation also significantly increased cell motility. The p38-specific inhibitor, SB203580, reduced the radiation-promoted migration of A549 cells, whereas SP600125, a JNK MAPK-specific inhibitor, inhibited both inherent and radiation-mediated cell motility. Consistent with this observation, radiation up-regulated the phosphorylation of p38 MAPK. Current approaches to cancer treatment involving more intensive radiotherapy regimens have been suggested to be associated with a higher incidence of local or distant metastasis. Therefore, a subset of patients may benefit from a combination of radiotherapy with inhibitors of EMT or cell migration.

Life expectancy of patients with newly-diagnosed HIV infection in the era of highly active antiretroviral therapy

BACKGROUND

Limited data are available on the life expectancy of patients with newly-diagnosed HIV infection in the era of highly active antiretroviral therapy (HAART).

AIM

To provide such an estimate using a semi-parametric projection.

DESIGN

Statistical analysis.

METHODS

Follow-up data for patients newly diagnosed with HIV infection in Taiwan (HIV/AIDS Cohort) from 1 May 1997 to 30 April 2003 (n = 3351, only 1% are injecting drug users) were analysed using the Kaplan-Meier method. The survival function for an age- and gender-matched reference population was generated by the Monte Carlo method from the life-table of the general population. A constant excess hazard model was used to project long-term survival of HIV-infected patients, with linear extrapolation of a logit-transformed curve of survival ratio between HIV-infected patients and the reference population.

RESULTS

The 5-year survival rate was 58% in patients who had already developed AIDS at diagnosis (AIDS group), and 89% in those who had not (non-AIDS group). Extrapolation yielded an expected mean survival time of 10.6 years after diagnosis for the AIDS group, and 21.5 years after diagnosis for the non-AIDS group.

DISCUSSION

Our results support the expansion of HIV screening programs to minimize delay in diagnosis. With continuing advances in HAART, this estimate of survival in initially asymptomatic patients may be conservative. Their long life expectancy raises questions about what kind of preventive heath services should be offered. These should be addressed through further analysis of overall benefit and cost-effectiveness.

The mitochondrial genome of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae)

We determined the complete nucleotide sequences of the mitochondrial genome (mitogenome) of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae). The entire mitochondrial DNA (mtDNA) molecule was 15,314 bp long. The C. raphaelis genes were in the same order and orientation as the completely sequenced mitogenomes of other lepidopteran species, except for the presence of an extra copy of tRNA(Ser)(AGN). High similarity in primary sequence and secondary structure between the two tandemly located copies of the tRNA(Ser)(AGN) suggest a recent duplication of an original single tRNA(Ser)(AGN). The DHU arm of the two copies of tRNA(Ser)(AGN) formed a simple loop as seen in many other metazoan mt tRNA(Ser)(AGN). The putative initiation codon for the C. raphaelis COI gene appears to be a tetranucleotide, TTAG, found commonly in the sequenced lepidopterans. ATPase8, ATPase6, ND4L and ND6 genes, which are next to another protein-coding gene at their 3' end all had the sequences potential to form a hairpin structure, suggesting the importance of such a structure for precise cleavage of the mature protein-coding genes.

The dermal stem cell factor and c-kit are overexpressed in melasma

BACKGROUND

The pathogenesis of melasma has not yet been clearly demonstrated. We tried to determine whether the stem cell factor (SCF) and its receptor c-kit are involved in the mechanism of hyperpigmentation of melasma because this factor is highly implicated in the stimulation of melanocyte function in vitro and in vivo.

OBJECTIVES

The present study was conducted to investigate the expression of SCF and c-kit on the lesions of melasma compared with nonlesional skin.

PATIENTS/METHODS

Skin samples were obtained from lesional and nonlesional facial skin of 60 Korean women with melasma. Immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to determine the expression of SCF and c-kit in melasma.

RESULTS

The expression of SCF was significantly increased at the lesional dermis compared with nonlesional dermis. However, there was no significant difference in the expression of SCF in lesional and nonlesional epidermis. The expression of c-kit was significantly increased at lesional epidermis compared with nonlesional skin. RT-PCR of SCF and c-kit mRNAs demonstrated increased expression of both types of transcripts in the lesional skin compared with nonlesional skin.

CONCLUSIONS

These results suggest that the increased expression of SCF in the dermis and of c-kit in the epidermis play an important role in the mechanism of hyperpigmentation in melasma.

Teriparatide vs. calcitonin in the treatment of Asian postmenopausal women with established osteoporosis

This study compared the clinical efficacy, safety, and tolerability of daily subcutaneous injections of teriparatide and salmon calcitonin in the treatment of postmenopausal women with established osteoporosis in Taiwan. This 6-month, multicenter, randomized, controlled study enrolled 63 women with established osteoporosis. They were randomized to receive either teriparatide 20 microg or calcitonin 100 IU daily in an open-label fashion. Lumber spine, femoral neck, total hip bone mineral density (BMD), and biochemical markers of bone turnover were measured, and adverse events and tolerability were recorded. The results at 6 months showed that patients using teriparatide had larger mean increases in spinal BMD than those who used calcitonin (4.5% vs. 0.1%), but the BMD changes in these two groups at the femoral neck and the total hip were not significant. There were also larger mean increases in bone markers in the teriparatide group than in the calcitonin group (bone specific alkaline phosphatase 142% vs. 37%; osteocalcin 154% vs. 23%). We conclude that teriparatide has more positive effects on bone formation than salmon calcitonin, as shown by the larger increments of lumbar spine BMD and bone formation markers, and caused only mild adverse events and no significant change in liver, kidney or hematological parameters. Compared with the published global results, teriparatide seems to be equally effective and safe to use in this Asian population.

Ifosfamide-induced encephalopathy with or without using methylene blue

Ifosfamide is one of the most widely used alkylating chemotherapeutic agents. Before mesna was introduced, its dose-limiting toxicity was hemorrhagic cystitis, but at present, neurotoxicity is one of its most worrisome side effects. A total of 10%-15% of patients treated with ifosfamide develop an encephalopathy. The exact pathophysiologic mechanisms responsible for the development of ifosfamide-induced encephalopathy (IIE) are not known. However, accumulation of chloracetaldehyde, toxic metabolite of ifosfamide, in the central nervous system is theorized to be the cause of the neurotoxicity. No standard treatment has been available for IIE. Recently, many reports suggested that methylene blue (MB) may be an effective treatment of this lethal complication. We report two cases of IIE and their treatment outcomes. The first patient recovered completely with MB. The other patient showed slow and incomplete improvement without using MB. We suggest that MB can be used as an initial treatment for the encephalopathy related to ifosfamide infusion. Thus, we present these two cases with brief review of related literature.

Clinical implications of N epsilon-(carboxymethyl)lysine, advanced glycation end product, in children and adolescents with type 1 diabetes

AIM

The aim of this study was to investigate the relationship between serum levels of the glycoxylation product N(epsilon)-(carboxymethyl)lysine (CML) and development of chronic diabetic complications and degree of diabetic control in children and adolescents with type 1 diabetes.

METHODS

The serum levels of CML were measured in 87 patients with uncomplicated type 1 diabetes mellitus (12.7 +/- 4.6 years of age) and in seven patients with background retinopathy, microalbuminuria or neuropathy (18.2 +/- 5.2 years of age) and compared with those in 64 normal control subjects (12.6 +/- 5.2 years of age). The mean durations of diabetes in uncomplicated and complicated patients were 5.0 +/- 3.4 years (0.1-14 years), and 8.6 +/- 5.0 years (3.1-18 years), respectively. The serum levels of CML were measured by enzyme-linked immunosorbent assay using a monoclonal anti-CML antibody (6D12).

RESULTS

The serum levels of CML were significantly higher in the patient group than those in the control group; 0.85 +/- 0.37 (0.37-1.93) U/ml vs. 0.56 +/- 0.23 (0.15-1.05) U/ml (p < 0.001) and significantly higher in the patient group with chronic complications than those in patient group without chronic complications; 1.06 +/- 0.39 (0.72-1.78) U/ml vs. 0.83 +/- 0.36 (0.37-1.93) U/ml (p < 0.05). Weak, but statistically significant relationship between CML levels and haemoglobin A(1c) levels at the measurement of CML was observed (r = 0.29, p < 0.05).

CONCLUSIONS

Our data are suggesting that higher serum levels of CML are involved in the development of chronic diabetic complications, and serum levels of CML reflect the degree of diabetic control for a long duration in type 1 diabetic children and adolescents.

Effects of polyhemoglobin-antioxidant enzyme complex on ischemia-reperfusion in kidney

INTRODUCTION

The kidney suffers ischemia-reperfusion (I/R) injury during transplantation. The purpose of the present study was to investigate the therapeutic effect of artificials cells on renal I/R injury through biochemical assays and histological examination.

METHODS

We prepared artificial cells using cross-linked hemoglobin (Hb), superoxide dismutase (SOD), and catalase. Normal male Sprague-Dawley rats were divided into 6 groups: the sham-operated control group, the group treated with polyHb,and the group treated with polyHb-SOD-catalase (PSC) (per groups were subjected to ischemia for 1 hour or 2 hours). After reperfusion for 4 hours, kidney and blood samples were obtained.

RESULTS

The levels of SOD and catalase in the PSC group were 15 and 50 times higher than those of the control group, respectively. In the polyHb group, the levels of blood urea nitrogen (BUN), serum creatinine, renal hydrogen peroxide, and renal malondialdehyde were increased. However, their levels were significantly decreased by PSC administration. Renal SOD activity did not show any significant changes in the polyHb group, but renal catalase activity was decreased by polyHb treatment in comparison with the control group. The activities of renal SOD and catalase were increased using PSC treatment. In the histological findings, the PSC group showed no evidence of acute tubular necrosis in proximal convoluted tubules; their microvilli and cytoplasmic microorganelles were relatively well preserved.

CONCLUSIONS

These results show that PSC effectively reduces renal damage via diminished oxygen free radical-mediated injury after I/R.

Effect of artificial cells on hepatic function after ischemia–reperfusion injury in liver

BACKGROUND

The liver suffers from ischemia/reperfusion injury during transplantation. Reactive oxygen species generated by xanthine oxidase during reperfusion of the ischemic liver may be partially responsible for the hepatic injury. Oxygen free radicals are removed by antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase. Using glutaraldehyde and lysine we constructed crosslinked hemoglobin, containing SOD and catalase, and assessed its ability to protect against ischemia/reperfusion injury during transplantation.

METHODS

In contrast to the sham-operated control groups, blood was exchanged using crosslinked hemoglobin (polyHb) a PolyHb-SOD-catalase (PSC) group. After ischemia/reperfusion injury, several parameters of hepatic damage and oxygen free radicals were measured as well as microscopic examination.

RESULTS

Alanine aminotransferase, aspartate aminotransferase, superoxide production, hydrogen peroxide, and malondialdehyde levels were higher among the PolyHb group than sham-operated controls. The PolyHb group revealed a few apoptotic bodies, some acute inflammatory infiltrates in the sinusoids, nuclear fragmentations, cell shrinkage, and chromatin clumping with formation of apoptotic bodies in the apoptotic cells under microscopic examination. Alanine aminotransferase, aspartate aminotransferase, superoxide production, and hydrogen peroxide levels were lower in the PSC than the PolyHb group. Hepatic structures were well preserved in the PSC group.

CONCLUSIONS

Reactive oxygen species contribute to hepatic dysfunction with morphologic changes. PSC is effective to reduce hepatic damage by lowering oxygen free radical-mediated injury after ischemia/reperfusion in the liver.

Pigment-lightening effect of N,N'-dilinoleylcystamine on human melanoma cells

BACKGROUND

Cystamine and linoleic acid have been reported to reduce melanin synthesis in vitro and in vivo. N,N'-dilinoleylcystamine (DLC) is a compound of cystamine and linoleic acid connected by an ester bond.

OBJECTIVES

To investigate the effects of DLC on melanin synthesis using cultured human melanoma cells.

METHODS

Levels of total melanin, eumelanin and phaeomelanin, tyrosinase protein and tyrosinase activity in situ were measured in HM3KO melanoma cells. Changes in degree of pigmentation were quantified by image analysis and compared with absorbance values. Tyrosinase from HM3KO cells was used to measure the direct effect of DLC on DOPA and DOPAchrome production.

RESULTS

At concentrations of 1.4-14 micromol L-1, DLC reduced the pigmentation of HM3KO melanoma cells but did not affect cell growth. The visual decrease in pigmentation produced by DLC was more dramatic than the decrease in total melanin content as measured by absorbance at 500 nm. DLC treatment decreased eumelanin synthesis and increased phaeomelanin synthesis in HM3KO melanoma cells. An in situ tyrosinase assay showed that DLC inhibited tyrosinase activity, as well as the level of tyrosinase protein.

CONCLUSIONS

These results suggest that DLC has pigment-lightening effects on HM3KO melanoma cells, produced by reducing the level of eumelanin while increasing the level of phaeomelanin.

Wax moth, Galleria mellonella, high density lipophorin receptor: alternative splicing, tissue-specific expression, and developmental regulation

A lipophorin (Lp) receptor cDNA from the fat body of Galleria mellonella (Lepidoptera) was cloned and sequenced. This is the first result in this order, Lepidoptera. It showed the pattern of the VLDL receptor belonging to the LDL receptor family. Sequence homology with other Lp receptors in insects, Locusta migratoria and Aedes aegypti, was 70 and 61%, respectively and each domain was highly conserved. Polyclonal anti-Lp receptor antibody prepared against expressed Lp receptor fragment between ligand binding domain and EGF-precursor homology domain (R305-D549 of amino acid residues) specifically detected the Lp receptor. Through immuno-blotting, the Lp receptor of larval fat body has an approximate molecular mass of about 97 and 110 kDa under non-reducing and reducing conditions, respectively. This result was in agreement with that of the ligand-blotting. The variant Lp receptors were expressed in the fat body of G. mellonella; one is an Lp receptor which lacks 84 bp of O-linked sugar domain and the other is a full length form of the Lp receptor. Both forms were detected by the polyclonal anti-Lp receptor antibody. The Lp receptor from the fat body of G. mellonella was differently expressed depending on the tissue and the developmental stage with specific abundance in prepupal stage. A steroid hormone, 20-hydroxyecdysone (20-HE) plays a crucial role in insect development. With regards to this conception, day 1-2 last instar larvae were treated with 20-HE and drastic induction of the Lp receptor was observed 48 h after treatment. It was also observed that cholesterol caused an induction of the Lp receptor.

An efficient motion estimation and compensation method for ultrasound synthetic aperture imaging

This paper describes a method for overcoming motion artifacts in synthetic aperture imaging. The method is based on a computer simulation study on the influence of target motion on synthetic aperture techniques. A region-based motion compensation approach is used in which only the axial motion is estimated and compensated for a given region of interest under the assumption that the whole ROI moves uniformly. The estimated axial motion is calculated with a crosscorrelation method at the point where the focused signal has the maximum energy within the ROI. We also present a method for estimating axial motion using the autocorrelation method that is widely used to estimate average Doppler frequency. Both computer simulations and in vivo experiments show that the proposed crosscorrelation-based method can greatly improve the spatial resolution and SNR of ultrasound imaging by implementing SA techniques for two-way dynamic focusing without motion artifacts. In addition, the autocorrelation-based motion compensation method provides almost the same results as the crosscorrelation-based method, but with a dramatically reduced computational complexity.

Isolation, identification and field tests of the sex pheromone of the carambola fruit borer, Eucosma notanthes

Two components, (Z)-8-dodecenyl acetate (Z8-12:Ac) and (Z)-8-dodecenol (Z8-12:OH), were isolated from sex pheromone glands of the carambola fruit borer, Eucosma notanthes, and were identified by GC, and GC-MS, chemical derivatization, and comparison of retention times. The ratio of the alcohol to acetate in the sex pheromone extracts was 2.7. However, synthetic mixtures (1 mg) in ratios ranging from 0.5 to 1.5 were more effective than other blends in trapping male moths in field tests.

Case report of a granular cell tumour in the nasal septum of a child

A six-year-old child with a nasal septal polyp presents with pain and nasal discharge. The diagnosis of a granular cell tumour was made histologically on excision of the polyp. This interesting case of an uncommon lesion presenting in a relatively rare paediatric age group is, as far as we know, the first report of a granular cell tumour involving the nasal septum.

Rac and p38 kinase mediate 5-lipoxygenase translocation and cell death

5-Lipoxygenase (5-LO) is a key enzyme involved in the synthesis of leukotrienes from arachidonic acid, and its activation is usually followed by translocation to the nuclear envelope. The details of mechanisms involved in the translocation of 5-LO are not well understood, though Ca(2+) is known to be essential. Here we show that ionomycin, a Ca(2+) ionophore, induces 5-LO translocation and necrotic cell death in Rat-2 fibroblasts, suggesting a potential relationship between activation of 5-LO and cell death. These effects were markedly attenuated in Rat2-Rac(N17) cells expressing a dominant negative Rac1 mutant. Pretreatment with SB203580, a specific inhibitor of p38 MAP kinase, or EGTA, a Ca(2+) chelator, likewise diminished ionomycin-induced 5-LO translocation and cell death, but PD98059, a MEK inhibitor, did not. Thus, Rac and p38 MAP kinase appear to be components in a Ca(2+)-dependent pathway leading to 5-LO translocation and necrotic cell death in Rat-2 fibroblasts.

Lenticular opacities in populations exposed to chronic low-dose-rate gamma radiation from radiocontaminated buildings in Taiwan

Chen, W-L., Hwang, J-S., Hu, T-H., Chen, M-S. and Chang, W. P. Lenticular Opacities in Populations Exposed to Chronic Low-Dose-Rate Gamma Radiation from Radiocontaminated Buildings in Taiwan. Radiat. Res. 156, 71-77 (2001). Epidemiological and experimental studies have revealed the cataractogenic potential of large acute doses of radiation. However, studies on the dose-response effect and the incidence of lenticular changes after exposure to chronic low doses of radiation have seldom been conducted. To evaluate quantitatively the lenticular changes in a population exposed to chronic low-dose-rate gamma radiation in their daily living or school environment in steel buildings contaminated with (60)Co in Taiwan, a total of 114 exposed individuals participated in a thorough ophthalmological examination in 1998. The lenticular opacities were evaluated by slit-lamp biomicroscopy after full pupil dilatation and were scored by the Lens Opacities Classification System III (LOCS III) and a modified subclinical minor lenticular focal defects system. These individuals were further divided into those less than 20 years old, those between 20 and 40 years old, and those more than 40 years old to evaluate the effects of age. The cumulative doses were assessed for each individual using the Taiwan Cumulative Dose (TCD) estimation system. A significant dose-dependent increase in the numbers of focal lens defects in those less than 20 years old was demonstrated, while less significant changes were observed in the other two age groups or by the LOCS III scoring. Results suggested that chronic low-dose-rate irradiation might induce minor lenticular changes, especially in lenses of young subjects. The delayed clinical changes in these young exposed subjects warrants further long-term follow-up.

Dynamics of changes in micronucleus frequencies in subjects post cessation of chronic low-dose radiation exposure

To assess DNA damage remaining in peripheral lymphocytes, 48 individuals were evaluated twice for lymphocyte micronucleus frequencies by the cytokinesis-blocking cytochalasin B (CBMN) analysis post relocation from radio-contaminated apartments after various periods of time. The frequencies of CBMN at the first evaluation were significantly higher than those at the second examination (Chang et al., 1999c). These individuals were categorized into three groups: those with cumulative exposure of >300 mSv (defined as high exposure, HDose), those with 100-300 mSv (MDose) and those with <100 mSv (LDose). Using the Poisson mixed-effect model (Little et al., 1996), the estimated mean CBMN frequencies ( per thousand) for individuals in HDose, MDose and LDose exposure categories when they had only recently relocated were 21.8, 17.6 and 15.4, respectively. The estimated mean duration post relocation for the CBMN frequencies of these individuals to reduce to 10.2, the second CBMN frequency, on average, was 47.5, 37.2 and 28.3 months in the three exposure groups, respectively. The rates of change in CBMN frequencies were shown to be significantly higher in the HDose group than in the MDose and LDose groups. The results suggested a characteristic dose-dependent decline in the CBMN frequencies in the exposed population post cessation of chronic low-dose ionizing radiation exposure.

Improvement of gene transfer to cervical cancer cell lines using non-viral agents

Virus-like particles (VLPs) composed of recombinant capsid protein L1 and L2 of human papillomavirus type 16 were conjugated with polylysine (PL) and gene transfer was performed using VLP-PL conjugates to allow the expression of targeted gene. When HeLa cells were incubated with VLP-PL conjugate coupled with plasmid cytomegalovirus beta-galactosidase (pCMVbeta-gal), about 10% of cells were transfected and demonstrated beta-galactosidase activity. Hence chloramphenicol acetyltransferase activity was also expressed significantly in VLP-PL-plasmid simian virus 2 chloramphenicol acetyl transferase (pSV2CAT)-transfected cells, VLP-PL conjugate was tested whether it could transfer a tumor suppressor gene, pCMVp53, to HeLa cells and the exogenously provided p53 gene complexed to VLP-PL conjugate was detected from HeLa cells by polymerase chain reaction (PCR) analysis. Interestingly, additional increase of transfection efficiency was demonstrated in the presence of poloxamer 407 when C-33A cells were transfected with VLP-PL-pCMVbeta-gal complex. The result support the notion that VLP-PL conjugate may be a promising vector to transfer genetic materials into cancer cells and poloxamer 407 can be used for enhancing the transfection efficiency of VLP-PL conjugate.

Physical heights of children with prolonged low dose-rate gamma-radiation exposure in radiocontaminated buildings

PURPOSE

To evaluate low dose-rate radiation effects on the physical heights of children staying in apartments with 60Co-contaminated steel construction.

MATERIALS AND METHODS

Children who once resided in radiocontaminated apartments since early 1983 were examined for height and body weight status from age 1 month to 18 years and before they moved out of the apartments. The physical heights and body weights of 21 898 age- and sex-matched non-exposed children from a nationwide school surveillance in 1997-98 were taken as controls. The physical height data were shown as height percentiles (HP) compared with reference children and age-specific relative height differences (RHD).

RESULTS

HP and RHD in 48 exposed boys and 37 girls were analysed using generalized estimating equations (GEE), which accounted for multiple measurements and correlation between these measurements in the same individuals during this period. After adjusting for effects from parental heights and body mass index (BMI), clear dose-related decreases in HP and RHD were observed in the exposed boys with a cumulative exposure > 60 mSv.

CONCLUSIONS

Prolonged low dose-rate y-radiation exposure was associated with adverse effects on the physical heights of growing boys, but were less apparent in the exposed girls.

A study of the display pixel-based focusing method in ultrasound imaging

This paper presents a new beamforming technique, in which ultrasound waves are focused at the display pixels on the Cartesian coordinates, rather than sampling points located on the uniformly-separated scanlines on either the polar or Cartesian coordinates. Consequently, this method does not require a digital scan converter (DSC) and therefore completely eliminates the distortions due to the DSC. A new imaging system based on the proposed method is also presented, which is advantageous over conventional systems in hardware complexity, especially when high-density imaging is required. The new method can also be used effectively to achieve high frame rates for real-time 3D imaging and cardiac applications. To verify the proposed method, we modified a commercial ultrasound scanner and performed experiments with a 3.5 MHz convex array and a 7.5 MHz linear array. The experimental results with in vivo and in vitro data show that the proposed technique provides much smoother and finer images than the conventional dynamic focusing methods.

Protective effects of (-)-epigallocatechin-3-gallate on UVA- and UVB-induced skin damage

It has been known that green tea and its components possess significant chemopreventive effects against chemical carcinogens and photo-caused skin tumor formation. In this study, the protective effects of (-)-epigallocatechin-3-gallate (EGCG), a major green tea catechin, on the ultraviolet (UV)-induced skin damage (photoaging) were studied in guinea pigs, hairless mice and human dermal fibroblast cultures. The lipid peroxidation was significantly reduced in the EGCG-treated group. The amount of lipid peroxides produced in the control and EGCG treated group were 838 +/- 144 and 286 +/- 57 nmol/mg at 18 h after UV irradiation, respectively. UVB-induced erythema was also significantly reduced in the EGCG treated group. The erythema relative index of the control and the EGCG treated group were 311 +/- 45 and 191 +/- 49 at 16 h after UV irradiation, respectively. EGCG treatment reduced UVA-induced skin damage (roughness and sagginess) and protected from the decrease of dermal collagen in hairless mouse skin. EGCG treatment blocked the UV-induced increase of collagen secretion and collagenase mRNA level in fibroblast culture. The nuclear transcription factors NF-kappaB and AP-1 binding activities were also inhibited by EGCG treatment.

The effects of glurenorm on plasma glucose and lipids in patients with type 2 diabetes mellitus

BACKGROUND

The effects of sulfonylureas on plasma glucose, lipids, and macrovascular complications are of interest. This study was designed to investigate the effects of glurenorm on plasma glucose and lipids in patients with type 2 diabetes mellitus.

METHODS

Nineteen patients, 15 men and 4 women, with an age range of 38-69 years, and with type 2 diabetes mellitus, were studied. Plasma glucose, glycated hemoglobin, and lipids were compared before and 3 months after glurenorm treatment.

RESULTS

Fasting and postprandial plasma glucose, and HbA1c significantly improved after 3 months of glurenorm treatment. The mean (+/- SD) triglyceride level of 10 patients with mild to moderate hypertriglyceridemia decreased from 279 +/- 66 to 219 +/- 100 mg/dl (p = 0.054). The total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) of 14 hypercholesterolemic patients did not change significantly. Their mean body weight increased significantly from 65.7 +/- 9.6 to 67.2 +/- 9.9 kg (p = 0.002).

CONCLUSION

Glurenorm was effective for glycemic control but caused weight gain in type 2 diabetic patients. Triglycerides in hypertriglyceridemic patients, and total cholesterol, LDL-C, and HDL-C in hypercholesterolemic patients did not improve after glurenorm treatment.

Subject-domain approach to the study of air pollution effects on schoolchildren's illness absence

In this paper, the authors propose a new statistical modeling technique, the subject-domain approach, which is theoretically proven to be equivalent to the time-domain approach in detecting an association between exposure and response with time trends. The authors use an empirical data set from a school absence monitoring study conducted during the 1994-1995 school year in Taiwan to demonstrate this subject-domain approach's application to environmental epidemiologic studies. Because the subject-domain models can control the influential personal confounding factors in the models, they show greater statistical power than the traditional time-domain approaches in determining the relation between air pollution and illness absences. The authors' models found that the schoolchildren's risks of illness absence were significantly related to acute exposures to nitrogen dioxide and nitrogen oxides with a 1-day lag (p < 0.01) at levels below the World Health Organization's guidelines. By contrast, the authors could not detect significant associations between air pollution and schoolchildren's absenteeism using time-domain approaches. Such findings imply that the models built on subject domain may be a general solution to the problem of the ecologic fallacy, which is commonly encountered in environmental and social epidemiologic studies.

Tissue-/stage-dependent expression of a cloned Bombyx mandarina QM homologue

QM, a novel gene that was firstly isolated as a putative tumor suppressor gene from Wilms' tumor cell line. Although it is well known that the QM gene product plays an important role within the tumor cells, the precise role of QM in the non-tumor cells has remained elusive. With in this mind we isolated a cDNA encoding QM homologue from Bombyx mandarina to understand the function of QM. The 596 bp cDNA has an open reading frame of 219 amino acids and a predicted mol. wt. of 25 kDa. The protein has more than 88% amino acid sequence identity to the QM protein from Drosophila melanogaster. mRNA expression gradually increased from 1-2 days after egg laying to 2 days of finial instar, while very low expressions were detected for either the pupae and the moth stages. The organs, posterior/middle division of silkgland, midgut, fat body and malpighian tubes, also show relatively high mRNA expression levels, respectively. The high degree of conservation and expression of the B. mandarina QM homologous suggest that it has a selectively conserved amino acid sequence due, presumably, to an important biological role which is associated with pupae formation.

Expression of functional influenza virus RNA polymerase in the methylotrophic yeast Pichia pastoris

Influenza virus RNA polymerase with the subunit composition PB1-PB2-PA is a multifunctional enzyme with the activities of both synthesis and cleavage of RNA and is involved in both transcription and replication of the viral genome. In order to produce large amounts of the functional viral RNA polymerase sufficient for analysis of its structure-function relationships, the cDNAs for RNA segments 1, 2, and 3 of influenza virus A/PR/8, each under independent control of the alcohol oxidase gene promoter, were integrated into the chromosome of the methylotrophic yeast Pichia pastoris. Simultaneous expression of all three P proteins in the yeast P. pastoris was achieved by the addition of methanol. To purify the P protein complexes, a sequence coding for a histidine tag was added to the PB2 protein gene at its N terminus. Starting from the induced P. pastoris cell lysate, we partially purified a 3P complex by Ni(2+)-agarose affinity column chromatography. The 3P complex showed influenza virus model RNA-directed and ApG-primed RNA synthesis in vitro but was virtually inactive without addition of template or primer. The kinetic properties of model template-directed RNA synthesis and the requirements for template sequence were analyzed using the 3P complex. Furthermore, the 3P complex showed capped RNA-primed RNA synthesis. Thus, we conclude that functional influenza virus RNA polymerase with the catalytic properties of a transcriptase is formed in the methylotrophic yeast P. pastoris.

Diagnosis and monetary quantification of occupational injuries by indices related to human capital loss: analysis of a steel company as an illustration

Prevention of occupational injuries is an important task of human resource management. In this study, new indices of human capital loss of occupational injury including cumulative injury rate, proportion of potential workdays lost, and potential salary lost were applied to the analysis of registry data of occupational injuries from 1986 to 1994 of a steel company in Taiwan. In addition, we compared these indices with disabling frequency rate and severity rate. The results showed that the average disabling frequency rate and cumulative injury rate of the whole company were 4.12 and 0.41, respectively; and the average disabling severity rate and proportion of potential workdays lost of the whole company were 563 and 229 x 10(-6), respectively, during 1986-1994. There was no consistent improvement in occupational safety in this period. The average potential salary lost of the whole company was more than US$ 2 million per year with a discount rate of 0.04, which was equivalent to 92 times of average annual income of a worker. The major monetary loss were due to non-traffic injuries of operators and traffic injuries of non-operators, which amounted to US$ 145 and 152 per person per year. As the new indices can provide additional information on lifetime occupational risk and human capital loss in monetary values, we concluded that they may be useful supplementary tools for monitoring and analyzing occupational injury data in a company.

Surgical repair of postinfarction ventricular septal defect

BACKGROUND

Rupture of the interventricular septum complicates 1% to 2% of all acute myocardial infarction patients and its natural course is ominous. The purpose of this study is to present our experience with surgical ventricular septal defect (VSD) repair and examine the possible risk factors and explanations for surgical mortality.

METHODS

Fourteen patients underwent repair of postinfarction VSD from 1996 to 1998 at the Taipei Veterans General Hospital. Thirteen patients were in New York Heart Association (NYHA) Functional Class IV and one was in Functional Class III. Eleven patients were in cardiogenic shock with intra-aortic balloon pumps (IABPs) prior to surgery. The operative techniques for VSD repair range from extensive infarctectomy with reconstruction of the septum and the right and left ventricular free walls using single or double patches, to minimal or no infarctectomy with closure of the VSD by excluding the infarcted muscle from the left ventricular cavity and leaving the right ventricle intact.

RESULTS

Overall surgical mortality occurred in four patients. All deaths occurred in patients with cardiogenic shock, two with anterior VSD and two with posterior VSD. Three late survivors had limited exercise tolerance with NYHA Functional Class II to III. Left ventricular function was moderately impaired in most patients with a mean nuclear scan ejection fraction of 0.32. However, all patients were elderly and adapted to their residual symptoms without significant life-style changes.

CONCLUSIONS

The surgical mortality for treating patients with postinfarction VSD has decreased with improvements in surgical technique. Rapid diagnosis, appropriate preoperative management and delicate surgical repair improve the overall results and help to attain long-term survival.

Frequency dependent study of the correlation functions in EPR spectroscopy--the Cole-Davidson approach 1. Perdeuterated 2,2,6,6-tetramethyl-4-piperidone N-oxide in toluene

EPR linewidth measurements of PD-Tempone in toluene at 1 (L-Band), 4 (S-Band), 9 (X-Band) and 34 GHz (Q-Band) microwave frequencies indicate the presence of a distribution of relaxation times. The empirical response parameter introduced by Cole-Davidson for the analysis of dielectric relaxation in liquids has been used for the analysis of EPR relaxation data in the low frequency region. The Cole-Davidson parameter can assume values in the range 0 < beta < or = 1. When beta = 1, one obtains the Debye-type spectral density. The calculated linewidth data at 1 GHz agrees with a Cole-Davidson distribution function with a width parameter 0.83 +/- 0.04 for a spherical solute. Beta < 1 at L-band suggests the presence of an asymmetrical distribution of relaxation times associated with different modes of relaxation mechanisms or internal molecular motions. This study shows EPR experiments at low microwave frequencies are more sensitive to the shape of the correlation function.

Molecular genetic relationships between Bombycidae and Saturniidae based on the mitochondria DNA encoding of large and small rRNA

The phylogenetic relationships between Bombycidae (Bombyx mori and Bombyx mandarina) and Saturniidae (Antheraea yamamai and Antheraea pernyi) were investigated based on large and small mitochondiral rRNA genes. About 430 bp of four kinds of PCR-amplified fragments were sequenced and aligned. For the 16S rRNA gene, B. mori shared a 98, 87 and 86% sequence homology with B. mandarina, A. yamamai and A. pernyi, and for the 12S rRNA gene, B. mori shared a 99, 89 and 88% sequence homology with B. mandarina, A. yamamai and A. pernyi, respectively. DNA sequence data were also used for a phylogenetic analysis. All of the trees showed monophyly for both Bombycidae and Saturniidae. The monophyly confidence limits of these trees were estimated using bootstrapping tests and measured more than 99% for all trees for both Bombycidae and Saturniidae.

An evaluation of risk estimation procedures for mixtures of carcinogens

The estimation of health risks from exposure to a mixture of chemical carcinogens is generally based on the combination of information from several available single compound studies. The current practice of directly summing the upper bound risk estimates of individual carcinogenic components as an upper bound on the total risk of a mixture is known to be generally too conservative. Gaylor and Chen (1996, Risk Analysis) proposed a simple procedure to compute an upper bound on the total risk using only the upper confidence limits and central risk estimates of individual carcinogens. The Gaylor-Chen procedure was derived based on an underlying assumption of the normality for the distributions of individual risk estimates. In this paper we evaluated the Gaylor-Chen approach in terms of the coverage probability. The performance of the Gaylor-Chen approach in terms the coverages of the upper confidence limits on the true risks of individual carcinogens. In general, if the coverage probabilities for the individual carcinogens are all approximately equal to the nominal level, then the Gaylor-Chen approach should perform well. However, the Gaylor-Chen approach can be conservative or anti-conservative if some or all individual upper confidence limit estimates are conservative or anti-conservative.

Molecular cloning and characterization of a cDNA encoding a transferrin homolog from Bombyx mori

We isolated a cDNA representing a message that was strongly induced by injection with E. coli in Bombyx mori. The 2160 bp cDNA has an open reading frame of 644 amino acids and the deduced product a predicted molecular mass of 71 kDa. The cDNA sequence shared high homology with the transferrins known so far, and its deduced peptide had unique features of transferrins, that is, sites of cystein residues and iron binding. We suggest that the B. mori transferrin plays an important role in the self-defense system.

Short-term effect of ozone on the pulmonary function of children in primary school

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter < or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations < 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.

Chronic low-dose gamma-radiation exposure and the alteration of the distribution of lymphocyte subpopulations in residents of radioactive buildings

PURPOSE

To elucidate the immunological change incurred in a human population by protracted gamma-radiation exposure at home environment.

MATERIALS AND METHODS

An examination on the CD3+, CD4+, CD8+ and HLA-DR+ lymphocyte subsets was arranged for 196 exposed subjects with mean excess cumulative dose of 169 mSv during 2-13 years of exposure. Another 55 close relatives of the exposed subjects were recruited as the non-exposed reference population.

RESULTS

The mean percentages of CD4+ T-lymphocytes, HLA-DR+ lymphocytes and the CD4+ /CD8+ ratios in the exposed subjects (35.5, 19.9 and 1.51 respectively) were significantly lower than those of reference individuals (38.0, 22.6 and 1.72; p= 0.02, 0.003, and 0.03 respectively), while the CD8+ in total counts of the exposed was moderately increased above that of the reference populations (p=0.1). By ANOVA analysis, the percentages of CD4+ and HLA-DR+ subsets were significantly associated with radiation dose (p=0.0046, 0.003), while CD4+/CD8+ ratios were moderately associated with dose (p=0.073). HLA-DR+ counts were significantly and positively associated with duration of relocation from radioactive apartments (p = 0.029).

CONCLUSIONS

Significant immunological effects were observed in those who had received chronic low-dose radiation exposure.

Metastasic oesophageal carcinoma to the paranasal sinuses--a case report

Metastasis to the paranasal sinuses is rare. We report a case of a patient with metastasis to the paranasal sinuses from carcinoma of the oesophagus. Our patient presented with symptoms mimicking the more common acute sinusitis. Although rare, metastatic disease of the paranasal sinuses should be considered especially in patients with a known primary carcinoma elsewhere presenting with sinu-nasal symptoms.

Follow-up in the micronucleus frequencies and its subsets in human population with chronic low-dose gamma-irradiation exposure

Forty-eight individuals, who received protracted low-dose rate gamma-irradiation from radioactive environments for 2-10 years, have been evaluated repetitively for cytogenetic damage by the cytochalasin-B micronuclei assay (CBMN) after they relocated from radioactive buildings. These subjects were shown to have a significant decrease in the CBMN frequencies during 26.2+/-8.4 months of follow-up. By the mixed effect multiple linear regression analysis, the CBMN frequencies in these 48 subjects during repetitive measurements were significantly associated with the relocation duration since leaving the radioactive environments (relocation time or RT in months; estimate -0.47, standard error 0. 0016, p value 0.0074). The alteration rate in the proportions of binucleates carrying a single micronucleus and those with multiple micronuclei was further compared among 26 of these exposed individuals. The proportions of binucleates with multi-micronuclei were shown to decline significantly faster than those with a mono-micronucleus between these two repetitive assays (proportional Z-test, p value 0.003). Moreover, some of the exposed subjects were shown to have a persistent increase in the total micronuclei frequencies or carrying multi-micronuclei in the binuclei even 3-4 years post-cessation of exposure. This suggests potential genomic instability in stem cells of the exposed individuals and the phenomenon deserves further closer monitoring. Understanding the dynamics of micronucleus expression in lymphocytes in subjects with previous mutagenic exposure would be of significant importance for human population monitoring.

Monte Carlo estimation of extrapolation of quality-adjusted survival for follow-up studies

The expected quality-adjusted survival (QAS) for an index population with a specific disease can be estimated by summing the product of the survival function and the mean quality of life function of the population. In many follow-up studies with heavy censoring, the expected QAS may not be well estimated due to the lack of data beyond the close of follow-up. In this paper, we first created a reference population from the life tables of the general population according to the Monte Carlo method. Secondly, we fitted a simple linear regression line to the logit of the ratio of quality-adjusted survival functions for the index and reference populations up to the end of follow-up. Finally, combining information on the reference population with the fitted line, we predicted the expected quality-adjusted survival curve beyond the follow-up period for the index population. Simulation studies have shown that the simple Monte Carlo estimation procedure is a potential approach for estimating expected QAS and the survival function beyond the follow-up with a certain degree of accuracy.