Accelerating space radiation countermeasure development through drug repurposing

The discovery of safe and effective radiation countermeasures (MCM) for long-duration spaceflight is challenging due to the complexity of the space radiation biology and high safety requirements. There are few if any clinically-validated molecular targets for this use case, and preclinical models have several known limitations. These challenges make the evaluation of existing FDA-approved drugs for this indication, or drug repurposing, an attractive strategy to accelerate space radiation countermeasure development. Drug repurposing offers several advantages over de novo drug discovery including established manufacturing methods, human clinical safety data, and well-understood dosing and pharmacokinetic considerations. There are limitations working with a fixed set of possible candidate compounds, but some properties of repurposed drugs can be tailored for well-defined new indications through reformulation and development of drug combinations. Drug repurposing is thus an attractive strategy for mitigating the high risks and costs of drug development and delivering new countermeasures to protect human from space radiation in long-term missions.

Potential effects of allyl isothiocyanate on inhibiting cellular proliferation and inducing apoptotic pathway in human cisplatin-resistant oral cancer cells

BACKGROUND/PURPOSE

Cisplatin-resistant oral cancer is clinically difficult to manage and the dose-dependent toxicities of cisplatin has been widely concerned. Allyl isothiocyanate (AITC), known as mustard oil, is a plant-derived compound abundant in cruciferous vegetables. It is reported to have anti-cancer potential as a natural dietary chemopreventive compound against a variety of cancers, but the effect of AITC on cisplatin-resistant cancer cells is still little-known.

METHODS

Human CAL27-cisplatin-resistant oral cancer cells (CAR cells) were examined to investigate the antitumor properties of AITC. 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay, IncuCyte™ S3 cell proliferation assay, 4',6-diamidino-2-phenylindole (DAPI) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining as well as Western blot analysis were deployed.

RESULTS

AITC decreased CAR cell viability, induced cell death of CAR cells and inhibited the confluences of cultured CAR cells. When CAR cells were treated with AITC, activation of caspase-3 and caspase-9 by AITC was observed and could be reversed by Z-VAD-fmk (pan-caspase inhibitor). Furthermore, the protein expressions of phosphorylated protein kinase B (p-AKT) and phosphorylated mammalian target of rapamycin (p-mTOR) were suppressed in AITC-treated CAR cells, whereas protein expressions of Bax, cytochrome c, Apaf-1, cleaved caspase-3, and cleaved caspase-9 were upregulated in AITC-treated CAR cells.

CONCLUSION

AITC can inhibit Akt/mTOR proliferation signaling and promote mitochondria-dependent apoptotic pathway through AITC-enhanced activities of caspase-3 and caspase-9 in CAR cells.

Impact of periodontal treatment on hospitalization for adverse respiratory events in asthmatic adults: A propensity-matched cohort study

BACKGROUND

Periodontal disease is prevalent in asthmatics, but it is unclear whether periodontal treatment plays a role in adverse respiratory events in these patients. We evaluated risk of hospitalization for adverse respiratory events (acute exacerbation, pneumonia, and acute respiratory failure) and mortality in asthmatic adults with and without periodontal treatment.

METHODS

We used National Health Insurance (NHI) claims data of Taiwan to identify 4771 asthmatic adults with periodontal disease who underwent periodontal treatment during 2000-2006. The control group consisted of asthmatic adults without periodontal disease at a 1:1 ratio matched by the propensity score. Both groups were followed up for 5years to estimate the risk of hospitalization for adverse respiratory events and mortality.

RESULTS

Compared with controls, the periodontal treatment group had lower overall incidence of hospitalization for adverse respiratory events [5.41 vs. 6.07 per 100 person-years, 95% confidence interval (CI)=0.78-0.92] and intensive care unit admissions (1.14 vs. 1.25 per 100 person-years, 95% CI=0.79-0.99). In addition, the all-cause mortality rate was significantly lower in the periodontal treatment group than in the control group during the follow-up period (1.86 vs. 2.79 per 100 person-years, 95% CI=0.59-0.71).

CONCLUSION

Asthmatic adults who underwent periodontal treatment were at lower risk of hospitalization for adverse respiratory events and mortality than those without periodontal disease. Asthmatic adults should adopt more precautionary oral hygiene and ensure that they undergo regular periodontal health checkups.

Arecoline N-Oxide Upregulates Caspase-8 Expression in Oral Hyperplastic Lesions of Mice

Areca nut is strongly associated with oral squamous cell carcinoma (OSCC) occurrence. Arecoline N-oxide (ANO), a metabolite of the areca alkaloid arecoline, exhibits an oral fibrotic effect in NOD/SCID mice. Caspase-8, a cysteine protease encoded by the CASP8 gene, is a central mediator in the extrinsic apoptotic pathway via death receptors. Deregulation of caspase-8 in OSCC has been reported. This study investigates the regulation of caspase-8 in ANO-induced oral squamous epithelial hyperplasia that represents the initial highly proliferative stage of oral carcinogenesis. CASP8 somatic mutations were identified from whole-exome sequencing of OSCC samples. Immunohistochemical staining showed upregulation of caspase-8 in ANO-induced hyperplasia of both NOD-SCID and C57BL/6 mice. Levels of expression of CASP8, APAF-1, BAX, and BAD increased in ANO-treated DOK cells. Co-localization of increased caspase-8 and PCNA levels was detected in ANO-induced hyperplastic lesions, whereas no co-localization among γ-H2A.X, caspase-3, and upregulated caspase-8 was observed. The findings indicate that upregulation of caspase-8 is involved in cell proliferation rather than apoptosis during the initial stage of ANO-mediated oral tumorigenesis.

Risk of Periodontal Disease in Patients With Asthma: A Nationwide Population-Based Retrospective Cohort Study

BACKGROUND

Studies have reported an association between asthma and oral diseases, including periodontal diseases. The aim of this retrospective study is to investigate risk of periodontal diseases for patients with asthma.

METHODS

Using the claims data of National Health Insurance of Taiwan and patients without a history of periodontal diseases, 19,206 asthmatic patients, who were newly diagnosed from 2000 through 2010, were identified. For each case, four comparison individuals without history of asthma and periodontal disease were randomly selected from the general population and frequency matched (categorical matched) by sex, age, and year of diagnosis (n = 76,824). Both cohorts were followed to the end of 2011 to monitor occurrence of periodontal diseases. Adjusted hazard ratios (aHRs) of periodontal disease were estimated using Cox proportional hazards regression analysis.

RESULTS

Overall incidence of periodontal diseases was 1.18-fold greater in the asthma cohort than in the comparison cohort (P <0.001). Patients with at least three emergency visits annually had an aHR of 55.9 (95% confidence interval [CI] = 50.6 to 61.7) for periodontal diseases compared with those with a mean of less than one visit. Patients with at least three admissions annually also had a similar aHR (51.8) for periodontal disease. In addition, asthmatic patients on inhaled corticosteroid (ICS) therapy had greater aHRs than non-users (aHR = 1.12; 95% CI = 1.03 to 1.23).

CONCLUSIONS

In the studied population, asthmatic patients are at an elevated risk of developing periodontal diseases. The risk is much greater for those with emergency medical demands or hospital admissions and those on ICS treatment.

Prevalence and risk of fracture diagnoses in women across the adult life span: a national cross-sectional study

In a national sample of women veterans, the rate of lower limb fracture diagnosis was the highest across ages 18-74 years; rates of fracture diagnosis of other skeletal sites peaked in women aged 75+. Women with two or more primary care visits or mental healthcare visits had elevated odds of fracture diagnosis.

INTRODUCTION

We assessed the prevalence and healthcare utilization characteristics associated with a diagnosis of any fracture in women of all adult ages within the Veterans Health Administration.

METHODS

In 344,488 women during fiscal year 2012, logistic regression models for fracture diagnosis included age, race/ethnicity, residence, number of primary care visits, number of mental healthcare visits, and degree of service-connected disability.

RESULTS

Lower limb fracture diagnosis was most prevalent across ages 18-74 years and peaked in women aged 55-64 years. In women aged 75+, the prevalence rates of fracture diagnosis at the hip (102, 95 % CI = 88-115 per 10,000 women), upper limb (100, 95 % CI = 87-114 per 10,000 women), and lower limb (84, 95 % CI = 72-97 per 10,000 women) were the highest. Fractures at other skeletal sites peaked in those aged 75+ years. Black women had the lowest odds of a fracture diagnosis, followed by Asian/Pacific Islander and Hispanic women compared to non-Hispanic White (by 25-51 %, P < 0.05). Having two or more primary care visits or any mental health visit was each associated with an increased risk. Women with five or more primary care visits had a 3.36-fold (95 % CI = 3.02-3.75) greater odds than those with no such visit, and separately, women with five or more mental health visits had a 1.51-fold (95 % CI = 1.43-1.60) greater odds. Women with a fracture diagnosis had higher overall healthcare costs than those without (P < 0.001).

CONCLUSIONS

Prevalence of fracture diagnosis differed by age, race/ethnicity, and skeletal site of fracture. Fracture diagnosis may identify women veterans with greater overall healthcare needs.

Periodontal Treatment Reduces Risk of Adverse Respiratory Events in Patients With Chronic Obstructive Pulmonary Disease: A Propensity-Matched Cohort Study

Treatment of periodontal diseases has been associated with benefit outcomes for patients with chronic obstructive pulmonary disease (COPD). However, no population-based cohort study has been conducted. We evaluated this relationship by retrospective cohort study using a large population data.Using the National Health Insurance claims data of Taiwan, we identified 5562 COPD patients with periodontal diseases who had received periodontal treatment as the treatment group. The comparison group was selected at a 1:1 ratio matched by the propensity score estimated with age, sex, date of COPD diagnosis and periodontal treatment, and comorbidities. Both groups were followed up for 5 years to compare risks of acute exacerbation, pneumonia, and acute respiratory failure.The incidence rates of adverse respiratory events were significantly lower in the treatment group than in the comparison group: 3.79 versus 4.21 per 100 person-years for emergency room visits, 2.75 versus 3.65 per 100 person-years for hospitalizations, and 0.66 versus 0.75 per 100 person-years for intensive care unit admissions. The treatment group also had a 37% reduced risk of deaths (1.81 vs 2.87 per 100 person-years), with an adjusted hazard ratio of 0.57 (95% confidence interval 0.52-0.62).Periodontal treatment for COPD patients could reduce the risk of adverse respiratory events and mortality. The adequate periodontal health care is important for COPD patients with periodontal diseases.

Association of SNPs in the PPARγ gene and hypertension in a Mongolian population

The association of single nucleotide polymorphisms (SNPs) in PPARγ with hypertension is controversial. The aim of the present study was to clarify the contributions of PPARγ genetic variants to hypertension through an association study. A total of 414 unrelated Mongolian herdsmen and 524 Han farmers were included in this study. Fourteen intronic SNPs were analyzed and genotyped using a polymerase chain reaction/ligase detection reaction assay. Prior to correction for multiple testing, the SNPs rs6802898 and rs12633551 were significantly associated with the prevalence of hypertension in the Han and Mongolian populations, respectively. The genetic association of each SNP with hypertension was individually tested using logistic regression. The SNP rs6802898 was associated with hypertension in both dominant (P = 0.033) and additive models (P = 0.026) in the Han population, whereas the SNP rs12633551 was associated with hypertension in both dominant (P = 0.014) and additive models (P = 0.0073) in the Mongolian population. Moreover, SNP rs12633551 had a significant effect on systolic and diastolic blood pressure response. However, none of these associations were statistically significant after Bonferroni correction for multiple testing, although there was a significant difference among the haplotypes in the Han and Mongolian populations. Interestingly, there was an association of the PPARγ haplotypes with hypertension even after Bonferroni correction. Thus, determination of the PPARγ haplotypes in different populations may prove informative for assessment of the genetic risk for hypertension.

Association of NPRA and NPRC gene variants and hypertension in Mongolian population

NPRA and NPRC are candidate susceptibility genes for essential hypertension (EH) and play a key role in the regulation of plasma levels and biological effects of natriuretic peptides. The aims of the present study were to find new genetic markers in the NPRA and NPRC genes and to assess relationships between variants and EH. A total of 797 unrelated Mongolian herdsmen were enrolled, including 389 EH patients and 408 normotensive controls. Genotyping was performed using the polymerase chain reaction/ligase detection reaction assay. The distribution of the T-allele frequency of rs1847018 in NPRC differed significantly between hypertensive subjects and controls. There was an association between rs1847018 and EH in the additive model in NPRC (P < 0.05). There were no significant differences in the genotype and allele frequency distributions for any of the 3 single nucleotide polymorphisms in NPRA between EH and normotensive individuals. In NPRA, the frequency of haplotype TCA in the EH group was significantly lower than in controls, while the frequency of haplotype TCG was significantly higher in the EH group than in controls; Individuals who possessed the TCA haplotype had a significantly lower risk of EH, whereas the presence of haplotype TCG was significantly associated with a higher risk of EH. However, there was no significant difference between the EH group and controls in any of the 8 haplotypes in NPRC. Rs1847018 is a genetic marker of EH in NPRC, and the frequency of haplotype TCA and TCG in NPRA is associated with EH in the Mongolian population.

Association of regulator of G protein signaling (RGS5) gene variants and essential hypertension in Mongolian and Han populations

Genetic variants of the RGS5 gene are believed to be risk factors for hypertension and cardiovascular diseases. In this study, we investigated the association between RGS5 gene variants and hypertension in the Mongolian and Han populations. Peripheral blood was obtained from 429 unrelated Mongolian herdsmen and 416 Han farmers [including essential hypertension (EH) patients and controls]. Nine tagSNPs within the RGS5 genes were retrieved from HapMap, and the samples were individually genotyped using the polymerase chain reaction/ligase detection reaction assay. The distribution of the allele frequency of rs12035879 differed significantly between hypertensive subjects and controls in the Han population, while the distribution of the allele and genotype frequencies of rs16849802 differed significantly between hypertensive subjects and controls in the Mongolian population. We observed an association between rs16849802 and EH in the Mongolian population. The frequency of haplotype GAA was significantly higher in the EH group than in controls in the Mongolian population. However, the EH group and controls did not differ significantly in all 6 haplotypes in the Han population. The rs16849802 and haplotype GAA independently increased the risk of EH in Mongolian patients, and may be used as a risk factor for the prediction of high blood pressure.

Risk of Periodontal Diseases in Patients With Chronic Obstructive Pulmonary Disease: A Nationwide Population-based Cohort Study

Several studies have reported an association between chronic obstructive pulmonary disease (COPD) and periodontal diseases. However, a large-scale population-based cohort study was previously absent from the literature. Therefore, we evaluated the risk of periodontal diseases in patients with COPD in a nationwide population.From the National Health Insurance claims data of Taiwan, we identified 22,332 patients with COPD who were newly diagnosed during 2000 to 2010. For each case, two individuals without COPD were randomly selected and frequency matched by age, sex, and diagnosis year. Both groups were followed up till the end of 2011.The overall incidence of periodontal diseases was 1.19-fold greater in the COPD group than in the comparison group (32.2 vs 26.4 per 1000 person-years; 95% confidence interval [CI] 1.15-1.24). Compared with non-COPD patients, the adjusted hazard ratios of patients with COPD increased with the number of emergency room visits (from 1.14 [95% CI 1.10-1.19] to 5.09 [95% CI 4.53-5.72]) and admissions (from 1.15 [95% CI 1.10-1.20] to 3.17 [95% CI 2.81-3.57]). In addition, the adjusted hazard ratios of patients with COPD treated with inhaled corticosteroids (1.22, 95% CI 1.11-1.34) and systemic corticosteroids (1.15, 95% CI 1.07-1.23) were significantly higher than those of patients not treated with corticosteroids.Patient with COPD are at a higher risk of developing periodontal diseases than the general population. Our results also support that the risk of periodontal diseases is proportional to COPD control. In addition, patients who receive corticosteroid treatment are at a higher risk of developing periodontal diseases.

Outcomes after surgery in patients with previous stroke

BACKGROUND

Limited information is available on the association between a medical history of stroke and postoperative outcomes. This study investigated the outcomes following non-neurological surgery in patients with previous stroke.

METHODS

Using Taiwan's National Health Insurance Research Database, a nationwide cohort study was conducted of patients who underwent non-neurological surgery between 2008 and 2010 with a medical history of stroke in the 24-month period before operation. Patients who had non-neurological surgeries without previous stroke were selected as controls by the propensity score-matched pair method. Thirty-day postoperative complications and in-hospital mortality were compared between the two groups.

RESULTS

Some 1 426 795 adults underwent major inpatient non-neurological surgery, of whom 45 420 had a medical history of previous stroke. Patients with previous stroke who underwent surgery had an increased risk of postoperative pneumonia, septicaemia, acute renal failure, acute myocardial infarction, pulmonary embolism and 30-day in-hospital mortality (adjusted rate ratio (RR) 1·79, 95 per cent c.i. 1·61 to 1·99). Compared with controls, patients with previous stroke due to intracerebral haemorrhage (RR 3·41, 2·97 to 3·91), and those who were treated in intensive care (RR 2·55, 2·24 to 2·90) or underwent neurosurgery (RR 2·49, 2·12 to 2·92), had an increased 30-day in-hospital mortality rate. Postoperative mortality also increased with stroke-related co-morbidities, and with stroke 1-6 months before surgery (RR 3·31, 2·91 to 3·75).

CONCLUSION

Patients with previous stroke had a higher risk of adverse postoperative outcomes; their 30-day in-hospital mortality rate was nearly twice that of patients without previous stroke.

Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells

Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.

Epigallocatechin gallate sensitizes CAL-27 human oral squamous cell carcinoma cells to the anti-metastatic effects of gefitinib (Iressa) via synergistic suppression of epidermal growth factor receptor and matrix metalloproteinase-2

Human head and neck squamous cell carcinoma (HNSCC) is a major cause of cancer-related death during the last decade due to its related metastasis and poor treatment outcomes. Gefitinib (Iressa), a tyrosine kinase inhibitor has been reported to reduce the metastatic abilities of oral cancer. Previous studies have shown that epigallocatechin gallate (EGCG), a green tea polyphenol, possesses cancer chemopreventive and anticancer activity. However, the mechanisms involved in the suppression of invasion and metastasis of human oral cancer cells following co-incubation with gefitinib and EGCG remain poorly understood. In the present study, we attempted to investigate the synergistic effects of a combined treatment of gefitinib and EGCG in CAL-27 cells in vitro and to elucidate the underlying molecular mechanisms associated with the supression of cell migration and invasion. In the present study, we found that the individual treatments or the combined treatment of gefitinib and EGCG synergistically inhibited the invasion and migration of CAL-27 cells using Transwell invasion and wound-healing scratch assays, respectively. Similarly, gefitinib in combination with EGCG synergistically attenuated enzymatic activity and the protein expression of MMP-2 in CAL-27 cells. Furthermore, individual or combined treatment with EGCG and gefitinib suppressed the protein expression of p-EGFR and the phosphorylated protein levels of ERK, JNK, p38 and AKT and displayed inhibitory effects on metastatic ability of CAL-27 cells. Combined effects of EGCG and gefitinib-altered anti-metastatic actions for related gene expression were observed using DNA microarray analysis. Importantly, EGCG sensitizes CAL-27 cells to gefitinib-suppressed phosphorylation of epidermal growth factor receptor (EGFR in vitro. Taken together, our results suggest that the synergistic suppression of the metastatic ability of CAL-27 cells after EGCG and gefitinib individual or combined treatment are mediated through mitogen-activated protein kinase (MAPK) signaling. Our novel findings provide potential insights into the mechanism involved with synergistic responses of gefitinib and EGCG against the progression of oral cancer.

Incidence and clinical significance of zygomaticomaxillary complex fracture involving the temporomandibular joint with emphasis on trismus

Trismus is frequently a sequel of temporomandibular joint (TMJ) involvement in a zygomaticomaxillary complex (ZMC) fracture. Although trismus is commonly observed in patients with ZMC fracture, continuous follow-up examinations of their degree of mouth opening have rarely been documented. The aim of this retrospective study was to determine the incidence and clinical significance of ZMC fracture involving the glenoid fossa or articular eminence of the TMJ with an emphasis on trismus. The medical and computed tomography (CT) imaging data of 28 patients with ZMC fracture treated by oral and maxillofacial surgeons (OMFSs) (OMFS group) and 174 patients with ZMC fracture treated by surgeons other than OMFSs (non-OMFS group) between May 2002 and May 2006 were reviewed. Maximal interincisal opening (MIO) less than 35 mm or three-finger width was considered limited mouth opening and indicative of trismus. Preoperative CT imaging data indicated that about 64% (18/28) and 50% (87/174) of the patients in the OMFS and non-OMFS groups, respectively, had a ZMC fracture involving the TMJ. Among these OMFS patients, 17 (94.40%) patients had limited mouth opening (MIO range, 7-33 mm) preoperatively, which improved markedly postoperatively. Among the non-OMFS patients with such fractures, 42 (48.3%) patients had trismus preoperatively and two retained trismus postoperatively. Lack of proper preoperative CT images, inadequate postoperative follow-up protocol, and/or neglect by patients and medical staff could influence the outcomes of ZMC fracture involving the TMJ. We make recommendations for reducing the risk of complications subsequent to ZMC fracture involving the TMJ.

Fusion yield enhancement in magnetized laser-driven implosions

Enhancement of the ion temperature and fusion yield has been observed in magnetized laser-driven inertial confinement fusion implosions on the OMEGA Laser Facility. A spherical CH target with a 10 atm D2 gas fill was imploded in a polar-drive configuration. A magnetic field of 80 kG was embedded in the target and was subsequently trapped and compressed by the imploding conductive plasma. As a result of the hot-spot magnetization, the electron radial heat losses were suppressed and the observed ion temperature and neutron yield were enhanced by 15% and 30%, respectively.

Lack of association of variants of the renal salt reabsorption-related genes SLC12A3 and ClC-Kb and hypertension in Mongolian and Han populations in Inner Mongolia

Abnormalities in renal sodium chloride and water reabsorption play important roles in the development of hypertension. Mutations in the genes involved in renal sodium chloride reabsorption can affect blood pressure. Recently, the R904Q variant of the sodium/chloride transporters, member 3 (SLC12A3) gene and the T481S variant of the chloride channel Kb (ClC-Kb) gene were found to be implicated in essential hypertension. We investigated a possible role of the SLC12A3 and ClC-Kb genes in the prevalence of essential hypertension in the Mongolian and Han ethnic groups. The study population comprised 308 unrelated Mongolians with essential hypertension, 271 Mongolian normotensives, 285 unrelated Han with essential hypertension, and 194 Han normotensives living in Inner Mongolia. The presence of the SLC12A3 R904Q and ClC-Kb-T481S polymorphisms was determined using TaqMan PCR. The risk factors for hypertension were age, body mass index, alcohol consumption, total plasma cholesterol, and low-density lipoprotein cholesterol. The genotype and allele frequencies of SLC12A3 R904Q and ClC-Kb-T481S were not significantly different between hypertensive patients and controls in the Mongolian (SLC12A3 R904Q, P = 0.471 and P = 0.494, ClC-Kb-T481S, P = 0.960 and P = 0.960, respectively) and Han (SLC12A3 R904Q, P = 0.765 and P = 0.777, ClC-Kb-T481S, P = 0.100 and P = 0.103, respectively) populations. There was no significant association between the SLC12A3 R904Q variant and the ClC-Kb-T481S variant and essential hypertension in either ethnic group.

Association of TSC gene variants and hypertension in Mongolian and Han populations

We investigated a possible association between genetic variations in the thiazide-sensitive Na-Cl cotransporter (TSC) gene and essential hypertension (EH) in the Mongolian and Han ethnic groups in Inner Mongolia. Our study included 385 unrelated Mongolian herdsmen and 523 Han farmers. Nine tagSNPs of TSC were identified from the Chinese HapMap database based on pairwise r(2) ≥ 0.5 and minor allele frequency ≥0.05. Genotyping was performed using the PCR/ligase detection reaction assay. Association between tagSNPs and hypertension was investigated under the additive model. There were significant differences between the genotype and allele frequencies of rs13306673 between the EH group and the control group in the Han population. Significant associations were found between the rs7204044 variant and EH in both the Mongolian and Han ethnic groups. The frequency of haplotype GCA in the EH group was significantly higher than in the control group in the Mongolian population. In the Han population, the frequency of haplotype TGG was significantly higher in the EH group than in controls, whereas haplotype TGA occurred significantly less often in EH than in controls. We suggest that rs7204044 of TSC is a genetic factor for EH in these two ethnicities and that rs13306673 is a genetic factor for EH in the Han population.

Mycophenolate mofetil monotherapy in the management of paediatric uveitis

PURPOSE

To evaluate effectiveness and safety of mycophenolate mofetil (MMF) monotherapy in paediatric autoimmune uveitis.

METHODS

We reviewed medical records of patients, 18 years of age or younger, with autoimmune uveitis treated with MMF at our practice from 2005 to 2009. The dose and duration of MMF therapy, inflammation status, visual acuity, previous immunomodulatory therapies, and adverse effects were recorded. In addition, the following subgroups were defined: (1) Durable Disease Control: patients whose uveitis remained quiescent for at least 2 years on MMF monotherapy, with no more than two flare-ups successfully treated with an increase in MMF dosage and/or a short course (<1 month) of corticosteroids; (2) Short-term Inflammation Control: patients whose uveitis remained quiescent for less than 2 years, with no more than one flare-up successfully treated with an increase in MMF dosage and/or a short course of corticosteroids, or who initially achieved inflammation control but discontinued MMF because of significant adverse effects.

RESULTS

A total of 38 out of 52 patients (73.1%) obtained inflammation control following 2 months of MMF monotherapy, achieving ≤ 0.5+ grading in anterior chamber cell/flare and vitreous haze. In the cross-sectional analysis, 25 patients (48.1%) met the criteria for Durable Disease Control, and 13 others (25.0%) qualified for Short-term Inflammation Control. Visual acuity remained stable or improved in 94.2% of the study population. Six patients (11.5%) discontinued MMF because of significant adverse effects, the most common of which was gastrointestinal disturbances.

CONCLUSION

MMF monotherapy appears to be an effective and safe treatment in paediatric autoimmune uveitis.

Biological impact of low dose-rate simulated solar particle event radiation in vivo

C57Bl6-lacZ animals were exposed to a range of low dose-rate simulated solar particle event (sSPE) radiation at the NASA-sponsored Research Laboratory (NSRL) at Brookhaven National Laboratory (BNL). Peripheral blood was harvested from animals from 1 to 12 days after total body irradiation (TBI) to quantify the level of circulating reticulocytes (RET) and micronucleated reticulocytes (MN-RET) as an early indicator of radiation-induced genotoxicity. Bone marrow lymphocytes and hippocampal tissues from each animal were collected at 12 days and up to two months, to evaluate dose-dependent late effects after sSPE exposure. Early hematopoietic changes show that the % RET was reduced up to 3 days in response to radiation exposure but recovered at 12 days postirradiation. The % MN-RET in peripheral blood was temporally regulated and dependant on the total accumulated dose. Total chromosome aberrations in lymphocytes increased linearly with dose within a week after radiation and remained significantly higher than the control values at 4 weeks after exposure. The level of aberrations in the irradiated animals returned to control levels by 8 weeks postirradiation. Measurements of chromosome 2 and 8 specific aberrations indicate that, consistent with conventional giemsa-staining methods, the level of aberrations is also not significantly higher than in control animals at 8 weeks postirradiation. The hippocampus was surveyed for differential transcriptional regulation of genes known to be associated with neurogenesis. Our results showed differential expression of neurotrophin and their associated receptor genes within 1 week after sSPE exposure. Progressive changes in the profile of expressed genes known to be involved in neurogenic signaling pathways were dependent on the sSPE dose. Our results to date suggest that radiation-induced changes in the hematopoietic system, i.e., chromosome aberrations in lymphocytes, are transient and do not persist past 4 weeks after radiation. On the other hand, alteration in the profile of genes known to be involved in neurotrophic functions in the hippocampal tissue appears to persist for up to 8 weeks after radiation exposure. Such temporal changes confirm that, although cytogenetic changes after a single dose of low-dose and low-dose-rate protons appear to be transient, the impact of this exposure is sufficient to lead to persistent dynamic changes in neuronal tissues long after the initial radiation exposure.

Generalized measurable ignition criterion for inertial confinement fusion

A multidimensional measurable criterion for central ignition of inertial-confinement-fusion capsules is derived. The criterion accounts for the effects of implosion nonuniformities and depends on three measurable parameters: the neutron-averaged total areal density (rhoR(n)(tot)), the ion temperature (T(n)), and the yield over clean (YOC=ratio of the measured neutron yield to the predicted one-dimensional yield). The YOC measures the implosion uniformity. The criterion can be approximated by chi=(rhoR(n)(tot))(0.8) x (T(n)/4.7)(1.7)YOC(mu)>1 (where rhoR is in g cm(-2), T in keV, and mu approximately 0.4-0.5) and can be used to assess the performance of cryogenic implosions on the NIF and OMEGA. Cryogenic implosions on OMEGA have achieved chi approximately 0.02-0.03.

Pars plana vitrectomy in the management of paediatric uveitis: the Massachusetts Eye Research and Surgery Institution experience

PURPOSE

To assess the effectiveness and safety of pars plana vitrectomy (PPV) in the management of chronic paediatric uveitis.

METHODS

We reviewed records of patients 16 years old or younger who underwent PPV due to persistent uveitis. Data including inflammatory status, ocular findings, visual acuity, dosage and duration of various medical therapies, surgical techniques and complications were collected.

RESULTS

Twenty-eight eyes of 20 patients were included in the study. The diagnoses of uveitis included pars planitis in 15 eyes (54%), idiopathic panuveitis in 8 eyes (29%), and juvenile idiopathic arthritis-associated iridocyclitis in five eyes (18%). Six eyes presented with associated retinal vasculitis. The mean age at the time of PPV was 11.2 years. The mean follow-up after surgery was 13.5 months. All 28 eyes had active uveitis with or without medical therapy at the time of PPV. At last follow-up, uveitis control was achieved with or without adjuvant medical therapy in 27 eyes (96%). These included five of the six eyes with persistent retinal vasculitis. Two eyes that had 20-G PPV developed intra-operative retinal tears. Four eyes with pre-operative clear lenses developed cataract within the first 6 months after PPV.

CONCLUSIONS

PPV is effective and safe in the management of chronic paediatric uveitis and its complications. It was able to reduce the amount of systemic medications required to control inflammation in this study. Patients with uveitis complicated by retinal vasculitis, however, are more likely to require long-term medical therapy to achieve inflammatory control.

Laser-driven magnetic-flux compression in high-energy-density plasmas

The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T. R. Boehly, Opt. Commun. 133, 495 (1997)10.1016/S0030-4018(96)00325-2] was used to implode cylindrical CH targets filled with deuterium gas and seeded with a strong external field (>50 kG) from a specially developed magnetic pulse generator. This seed field was trapped (frozen) in the shock-heated gas fill and compressed by the imploding shell at a high implosion velocity, minimizing the effect of resistive flux diffusion. The magnetic fields in the compressed core were probed via proton deflectrometry using the fusion products from an imploding D3He target. Line-averaged magnetic fields between 30 and 40 MG were observed.

Seeding magnetic fields for laser-driven flux compression in high-energy-density plasmas

A compact, self-contained magnetic-seed-field generator (5 to 16 T) is the enabling technology for a novel laser-driven flux-compression scheme in laser-driven targets. A magnetized target is directly irradiated by a kilojoule or megajoule laser to compress the preseeded magnetic field to thousands of teslas. A fast (300 ns), 80 kA current pulse delivered by a portable pulsed-power system is discharged into a low-mass coil that surrounds the laser target. A >15 T target field has been demonstrated using a <100 J capacitor bank, a laser-triggered switch, and a low-impedance (<1 Omega) strip line. The device has been integrated into a series of magnetic-flux-compression experiments on the 60 beam, 30 kJ OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The initial application is a novel magneto-inertial fusion approach [O. V. Gotchev et al., J. Fusion Energy 27, 25 (2008)] to inertial confinement fusion (ICF), where the amplified magnetic field can inhibit thermal conduction losses from the hot spot of a compressed target. This can lead to the ignition of massive shells imploded with low velocity-a way of reaching higher gains than is possible with conventional ICF.

Particle radiation alters expression of matrix metalloproteases resulting in ECM remodeling in human lens cells

Relatively low doses of space radiation have been correlated with an increased incidence and earlier appearance of cataracts in space travelers. The lens is a radiosensitive organ of the body with a very obvious late end point of radiation damage--cataract. However, many molecular changes occur in the lens soon after radiation exposure and long before the appearance of an opacification. The goal of our research is to elucidate early mechanisms associated with particle radiation-induced cataractogenesis, with the ultimate goal of developing countermeasures. Normal, cultured non-immortalized human lens cells were grown on matrix-coated plastic tissue culture vessels and irradiated with particle beams at Lawrence Berkeley National Lab (LBNL) or at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Lab. Samples were harvested at different times after radiation exposure. Using a focused genetic approach, total RNA and protein extracts from control and irradiated samples were processed and probed for the expression of genes associated with extracellular matrix (ECM) proteases. Matrix metalloproteinases (MMPs) have previously been studied in adult postmortem human lenses, in post-cataract intraocular lens (IOL) surgery capsular bags and with immortalized human lens cell cultures. Significant differences exist in the expression pattern with these various model systems. We have evidence for the cell stage-specific expression of MMP family of genes during lens fiber differentiation, and for radiation-induced alterations in the misregulation of MMP expression. Our data indicate that radiation exposure may lead to differences in the expression of radiation stress responses, which may impact selective ECM remodeling and cell differentiation.

Evaluation of the impact of shielding materials in radiation protection in transgenic animals

We are using a plasmid-based transgenic mouse mutation model system to evaluate the effectiveness of aluminum or low-density polyethylene (LDPE) shielding after 250 MeV/u protons or 1 GeV/u iron ion irradiation. Transgenic mice, with multiple copies of the plasmid pUR288 lacZ transgene integrated into the genome of every cell of the animal, were either irradiated or sham-treated. Multiple endpoints, including early cytogenetic damage in erythrocytes at 48 h after exposure, chromosome aberrations in bone marrow lymphocytes, and lacZ mutant frequencies (MF) in brain and spleen tissues were measured in the same animals. The frequency of total circulating reticulocytes (fRET) dropped precipitously at 48 h after 2 Gy of proton irradiation. The average level of micronucleated reticulocytes (fMN-RET) was fivefold higher in the irradiated samples relative to the controls at the same time point. There was an increase in total chromosome aberrations in bone marrow lymphocytes at 8 weeks after proton irradiation but this increase was not statistically significant relative to the controls. Evaluation of the lacZ MF in the brain and spleen tissues showed that proton irradiation induced a twofold increase in MF in each tissue. Similar samples were collected from animals that were shielded from the proton beam by aluminum. Compared to the unshielded treatment group, we noted no difference in fRET, fMN-RET, chromosome aberrations in lymphocytes and lacZ MF in brain and spleen tissues obtained from these animals. In a separate study, animals were exposed to high-energy iron ions with or without 10 or 15 cm LDPE. Using the same approach, we noted a precipitous drop in fRET, and an elevation in fMN-RET within 48 h after 1 Gy of iron ions. Total chromosome aberrations in bone marrow lymphocytes were slightly elevated but not significant at 8 weeks after iron ion exposure. Shielding animals with 10 or 15 cm of polyethylene appeared to have no effect on the level of RET, MN-RET or chromosome aberrations in these animals. LacZ MF in brain and spleen tissues increased 1.5-2-fold above control levels after 1 Gy iron ions at 8 weeks after treatment. On the other hand, MF in tissues harvested from shielded animals appeared to be lower than their unshielded litermates, suggesting the polyethylene shielding was effective in reducing the iron-induced genomic damage in tissues. Although shielding may be effective, in some cases, in reducing the physical dose of particle radiation, our cytogenetic results showed that the biological impact of the particle beam remain unchanged. On the other hand, reduction in transgene MF in tissues from LDPE-shielded animals but not in the aluminum-shielded animals strongly suggests that careful consideration of the biological endpoints used is necessary in the evaluation of the efficacy of the selected shielding material.

Effects of iron ions, protons and X rays on human lens cell differentiation

We have investigated molecular changes in cultured differentiating human lens epithelial cells exposed to high-energy accelerated iron-ion beams as well as to protons and X rays. In this paper, we present results on the effects of radiation on gene families that include or are related to DNA damage, cell cycle regulators, cell adhesion molecules, and cell cytoskeletal function. A limited microarray survey with a panel of cell cycle-regulated genes illustrates that irradiation with protons altered the gene expression pattern of human lens epithelial cells. A focus of our work is CDKN1A (p21(CIP1/WAF1)), a protein that we demonstrate here has a role in several pathways functionally related to LET-responsive radiation damage. We quantitatively assessed RNA and protein expression in a time course before and after single 4-Gy radiation doses and demonstrated that transcription and translation of CDKN1A are both temporally regulated after exposure. Furthermore, we show qualitative differences in the distribution of CDKN1A immunofluorescence signals after exposure to X rays, protons or iron ions, suggesting that LET effects likely play a role in the misregulation of gene function in these cells. A model of molecular and cellular events is proposed to account for precataractous changes in the human lens after exposure to low- or high-LET radiations.

Interpretation and Optimization of Absorbance and Fluorescence Signals from Voltage-sensitive Dyes

Voltage-sensitive dyes produce absorbance and fluorescence changes that can be used to image voltage. The present study develops a systematic approach to the optimization of these signals. A mathematical analysis assesses the dye optical density ( OD) that optimizes the signal-to-noise ratio in absorbance and fluorescence measurements. The signal-to-noise ratio is maximal for a dye OD of 2 (natural logarithm) in absorbance and ~1 in fluorescence. The fluorescence result is approximate because, in contrast to absorbance, the optimal dye OD varies with the amount of scattering and intrinsic absorbance of the tissue. The signal-to-noise ratio of absorbance is higher in thick preparations such as brain slices; fluorescence is superior in thin preparations such as cell culture. The optimal OD for absorbance and fluorescence, as well as the superiority of absorbance, were confirmed experimentally on hippocampal slices. This analysis also provided insight into the interpretation of signals normalized to resting light intensities. With both absorbance and fluorescence, the normalized signal (Delta I/I) varies with OD, and does not reflect the change in dye absorbance. In absorbance this problem is remedied by dividing Delta I/I by the dye OD to obtain the absorbance change. For fluorescence a correction is possible, but is more complicated. Because this analysis indicates that high levels of stain optimize the signal-to-noise, dyes were tested for pharmacological actions and phototoxicity. The absorbance dye RH155 was found to have pharmacological action at high staining levels. The fluorescent dye RH414 was phototoxic. Adverse effects could not be detected with the absorbance dye RH482.

Modulation of lens cell adhesion molecules by particle beams

Cell adhesion molecules (CAMs) are proteins which anchor cells to each other and to the extracellular matrix (ECM), but whose functions also include signal transduction, differentiation, and apoptosis. We are testing a hypothesis that particle radiations modulate CAM expression and this contributes to radiation-induced lens opacification. We observed dose-dependent changes in the expression of beta 1-integrin and ICAM-1 in exponentially-growing and confluent cells of a differentiating human lens epithelial cell model after exposure to particle beams. Human lens epithelial (HLE) cells, less than 10 passages after their initial culture from fetal tissue, were grown on bovine corneal endothelial cell-derived ECM in medium containing 15% fetal bovine serum and supplemented with 5 ng/ml basic fibroblast growth factor (FGF-2). Multiple cell populations at three different stages of differentiation were prepared for experiment: cells in exponential growth, and cells at 5 and 10 days post-confluence. The differentiation status of cells was characterized morphologically by digital image analysis, and biochemically by Western blotting using lens epithelial and fiber cell-specific markers. Cultures were irradiated with single doses (4, 8 or 12 Gy) of 55 MeV protons and, along with unirradiated control samples, were fixed using -20 degrees C methanol at 6 hours after exposure. Replicate experiments and similar experiments with helium ions are in progress. The intracellular localization of beta 1-integrin and ICAM-1 was detected by immunofluorescence using monoclonal antibodies specific for each CAM. Cells known to express each CAM were also processed as positive controls. Both exponentially-growing and confluent, differentiating cells demonstrated a dramatic proton-dose-dependent modulation (upregulation for exponential cells, downregulation for confluent cells) and a change in the intracellular distribution of the beta 1-integrin, compared to unirradiated controls. In contrast, there was a dose-dependent increase in ICAM-1 immunofluorescence in confluent, but not exponentially-growing cells. These results suggest that proton irradiation downregulates beta 1-integrin and upregulates ICAM-1, potentially contributing to cell death or to aberrant differentiation via modulation of anchorage and/or signal transduction functions. Quantification of the expression levels of the CAMs by Western analysis is in progress.

HZE particle radiation induces tissue-specific and p53-dependent mutagenesis in transgenic animals

Transgenic animals, with the integrated target gene, provide a unique approach for measuring and characterizing mutations in any tissue of the animal. We are using the plasmid-based lacZ transgenic mice with different p53 genetic background to examine radiation-induced genetic damage resulting from exposure to heavy particle radiation. We measured lacZ mutation frequencies (MF) in the brain and spleen tissues at various times after exposing animals to an acute dose of 1 Gy of 1GeV/amu iron particles. MF in the spleen of p53+/+ animals increased up to 2.6-fold above spontaneous levels at 8 weeks post irradiation. In contrast, brain MF from the same animals increased 1.7-fold above controls in the same period. In the p53-/- animals, brain MF increased to 2.2-fold above spontaneous levels at 1 week after treatment, but returned to control levels thereafter. Radiation also induced alterations in the spectrum of mutants in both tissues, accompanied by changes in the frequency of mutants with deletions extending past the transgene into mouse genomic DNA. Our results indicate that the accumulation of transgene MF after radiation exposure is dependant on the tissue examined as well as the p53 genetic background of the animals.

Synaptotagmin modulation of fusion pore kinetics in regulated exocytosis of dense-core vesicles

In the exocytosis of neurotransmitter, fusion pore opening represents the first instant of fluid contact between the vesicle lumen and extracellular space. The existence of the fusion pore has been established by electrical measurements, but its molecular composition is unknown. The possibility that synaptotagmin regulates fusion pores was investigated with amperometry to monitor exocytosis of single dense-core vesicles. Overexpression of synaptotagmin I prolonged the time from fusion pore opening to dilation, whereas synaptotagmin IV shortened this time. Both synaptotagmin isoforms reduced norepinephrine flux through open fusion pores. Thus, synaptotagmin interacts with fusion pores, possibly by associating with a core complex of membrane proteins and/or lipid.

Computer-aided measurement and grading of cranial asymmetry in children with and without torticollis

Our aim was to develop a simple, non-invasive method that could be used to objectively record cranial symmetry over time. We utilized this new method to investigate the relationship between torticollis and progressive plagiocephaly. From 1995 to 1999, the head shapes of 419 torticollis patients and 1 211 normal children were evaluated. We used Ezeform strip, a splint material, to make a permanent ring of the head circumference. Each head ring was recorded, scanned, and analyzed. An asymmetric index (AI) was designed. Double-blind comparisons of clinical assessment with AI values demonstrated a good agreement. Asymmetry of the cranium was found with similar frequency in torticollis and normal babies up to 12 months old. After 1 year of age, the deformity persists in patients with torticollis into their adolescence, while the normal group shows increased symmetry. This new recording system offers an objective and efficacious methods for following the natural history of cranial asymmetry.

Oxidized low-density lipoprotein downregulates endothelial basic fibroblast growth factor through a pertussis toxin-sensitive G-protein pathway: mediator role of platelet-activating factor-like phospholipids

BACKGROUND

Oxidized LDL (oxLDL) inhibits angiogenesis in part by downregulating endothelial basic fibroblast growth factor (bFGF). To determine the mechanism of the downregulation, we investigated the signal transduction pathway involving potential phospholipid mediators.

METHODS AND RESULTS

Cultured bovine aortic endothelial cells were incubated with PBS (lipoprotein-free control), LDL, or copper oxLDL under serum-free conditions. At 24 hours, oxLDL (50 microg/mL) decreased bFGF mRNA (Northern blot), bFGF protein (Western blot and ELISA), and concomitant DNA synthesis, all by 40% to 50% compared with PBS. LDL had no effect. Pretreating the cells with 100 ng/mL pertussis toxin (PTX) for 18 hours before oxLDL exposure almost completely blocked the inhibitory effects of oxLDL. In contrast, inhibiting other major cellular signal transduction pathways with PD-98059 (mitogen-activated protein kinase kinase inhibitor), HA-1004 (inhibitor of cGMP- and cAMP-dependent protein kinase), or Ro-31-8220 (protein kinase C inhibitor) or chelating intracellular Ca(2+) with BAPTA-AM failed to attenuate any of the oxLDL effects assayed. Addition to the cultures of WEB 2086, a specific antagonist of the PTX-sensitive G protein-coupled platelet-activating factor (PAF) receptor, blocked the action of oxLDL. Whereas PAF dispersed in the culture medium failed to produce oxLDL-like effects, degradation of PAF and PAF-like phospholipids accumulated in oxLDL with a recombinant human PAF acetylhydrolase eliminated the inhibitory effects of oxLDL on bFGF expression and DNA synthesis.

CONCLUSIONS

OxLDL suppresses endothelial bFGF expression and DNA synthesis through a PTX-sensitive heterotrimeric G-protein pathway involving mediator phospholipids similar, but not identical, to PAF.

Dolichol-phosphate-mannose-3 (DPM3)/prostin-1 is a novel phospholipase C-gamma regulated gene negatively associated with prostate tumor invasion

The most ominous development in tumor progression is the transition to an invasive and metastatic phenotype. Little is known, however, about the molecular alterations that cause a tumor to become invasive. In view of this, we have used microarray expression analysis to evaluate the expression profiles of a unique panel of human DU145 prostate cancer sublines that vary in their invasive potential. The three DU145 sublines expressed epidermal growth factor (EGF) receptors that differed in their ability to activate phospholipase C-gamma (PLC gamma). Three-way analyses yielded 11 genes out of 4608 genes screened that associated directly or inversely with invasive potential. The gene whose expression correlated most strongly with lack of invasion was identified as a potential invasion suppressor and called prostin-1. Pharmacological inhibition of PLC gamma (U73122) confirmed that PLC gamma signaling suppressed prostin-1 in that U73122 treatment caused induction of prostin-1 in PLC gamma competent cells. The prostin-1 gene, conserved through phylogeny, is induced by androgen in LNCaP cells and encodes a 92 amino acid protein. The protein shares no extensive homologies with other known genes, yet was recently identified as a small stabilizer subunit of the dolichol-phosphate-mannose (DPM) synthase complex. That DPM3/prostin-1 might suppress tumor progression was supported by the finding that exogenous expression in COS cells leads to apoptosis. These findings support the use of model cell lines to identify putative tumor suppressors and promoters.

p53 deficiency alters the yield and spectrum of radiation-induced lacZ mutants in the brain of transgenic mice

Exposure to heavy particle radiation in the galacto-cosmic environment poses a significant risk in space exploration and the evaluation of radiation-induced genetic damage in tissues, especially in the central nervous system, is an important consideration in long-term manned space missions. We used a plasmid-based transgenic mouse model system, with the pUR288 lacZ transgene integrated in the genome of every cell of C57Bl/6(lacZ) mice, to evaluate the genetic damage induced by iron particle radiation. In order to examine the importance of genetic background on the radiation sensitivity of individuals, we cross-bred p53 wild-type lacZ transgenic mice with p53 nullizygous mice, producing lacZ transgenic mice that were either hemizygous or nullizygous for the p53 tumor suppressor gene. Animals were exposed to an acute dose of 1 Gy of iron particles and the lacZ mutation frequency (MF) in the brain was measured at time intervals from 1 to 16 weeks post-irradiation. Our results suggest that iron particles induced an increase in lacZ MF (2.4-fold increase in p53+/+ mice, 1.3-fold increase in p53+/- mice and 2.1-fold increase in p53-/- mice) and that this induction is both temporally regulated and p53 genotype dependent. Characterization of mutants based on their restriction patterns showed that the majority of the mutants arising spontaneously are derived from point mutations or small deletions in all three genotypes. Radiation induced alterations in the spectrum of deletion mutants and reorganization of the genome, as evidenced by the selection of mutants containing mouse genomic DNA. These observations are unique in that mutations in brain tissue after particle radiation exposure have never before been reported owing to technical limitations in most other mutation assays.

Particle irradiation induces FGF2 expression in normal human lens cells

Particle Irradiation Induces FGF2 Expression in Normal Human Lens Cells. Particle radiations, including both proton and helium-ion beams, have been used to successfully treat choroidal melanoma, but with the complication of radiation-induced cataract. We have investigated a role for radiation-induced changes in the expression of basic fibroblast growth factor (FGF2) gene expression as part of the mechanism(s) underlying lens cell injury associated with cataract. Normal human lens epithelial (HLE) cells were cultured in vitro on extracellular matrix (ECM) originated from bovine corneal endothelial cells. This study reports evidence for rapid but transient induction of FGF2 transcripts, an increase of between 5- and 8-fold, within 0.5 h after exposure to particle radiation, followed by another wave of increased transcription at 2-3 h postirradiation. Immunofluorescence results confirm the enhanced levels of FGF2 protein rapidly after exposure to protons or helium ions, followed by another wave of increased activity unique to helium at 6 h postirradiation. This second wave of increased immunoreactivity was not observed in the proton-irradiated samples. Total FGF2 protein analysis after helium-ion exposures shows induced expression of three FGF2 isoforms, with an increase of up to 2-fold in the 18-kDa low-molecular-weight species. Studies of the effects of protons on individual FGF2 protein isoforms are in progress. Several mechanisms involving a role for FGF2 in radiation-induced cataract are discussed.

Growth and differentiation of human lens epithelial cells in vitro on matrix

PURPOSE

To characterize the growth and maturation of nonimmortalized human lens epithelial (HLE) cells grown in vitro.

METHODS

HLE cells, established from 18-week prenatal lenses, were maintained on bovine corneal endothelial (BCE) extracellular matrix (ECM) in medium supplemented with basic fibroblast growth factor (FGF-2). The identity, growth, and differentiation of the cultures were characterized by karyotyping, cell morphology, and growth kinetics studies, reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, and Western blot analysis.

RESULTS

HLE cells had a male, human diploid (2N = 46) karyotype. The population-doubling time of exponentially growing cells was 24 hours. After 15 days in culture, cell morphology changed, and lentoid formation was evident. Reverse transcription-polymerase chain reaction (RT-PCR) indicated expression of alphaA- and betaB2-crystallin, fibroblast growth factor receptor 1 (FGFR1), and major intrinsic protein (MIP26) in exponential growth. Western analyses of protein extracts show positive expression of three immunologically distinct classes of crystallin proteins (alphaA-, alphaB-, and betaB2-crystallin) with time in culture. By Western blot analysis, expression of p57(KIP2), a known marker of terminally differentiated fiber cells, was detectable in exponential cultures, and levels increased after confluence. MIP26 and gamma-crystallin protein expression was detected in confluent cultures, by using immunofluorescence, but not in exponentially growing cells.

CONCLUSIONS

HLE cells can be maintained for up to 4 months on ECM derived from BCE cells in medium containing FGF-2. With time in culture, the cells demonstrate morphologic characteristics of, and express protein markers for, lens fiber cell differentiation. This in vitro model will be useful for investigations of radiation-induced cataractogenesis and other studies of lens toxicity.

Increased expression of GAD65 and GABA in pancreatic beta-cells impairs first-phase insulin secretion

The functional role of glutamate decarboxylase (GAD) and its product GABA in pancreatic islets has remained elusive. Mouse beta-cells express the larger isoform GAD67, whereas human islets express only the smaller isoform GAD65. We have generated two lines of transgenic mice expressing human GAD65 in pancreatic beta-cells (RIP7-hGAD65, Lines 1 and 2) to study the effect that GABA generated by this isoform has on islet cell function. The ascending order of hGAD65 expression and/or activity in beta-cells was Line 1 heterozygotes < Line 2 heterozygotes < Line 1 homozygotes. Line 1 heterozygotes have normal glucose tolerance, whereas Line 1 homozygotes and Line 2 heterozygotes exhibit impaired glucose tolerance and inhibition of insulin secretion in vivo in response to glucose. In addition, fasting levels of blood glucose are elevated and insulin is decreased in Line 1 homozygotes. Pancreas perfusion experiments suggest that GABA generated by GAD65 may function as a negative regulator of first-phase insulin secretion in response to glucose by affecting a step proximal to or at the K(ATP)(+) channel.

Effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development

BACKGROUND AND PURPOSE

Angiogenesis is regulated by various factors, including vascular endothelial growth factor (VEGF). Five isoforms of VEGF have been discovered: VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206. The teleologic basis for the various VEGF isoforms remains unclear, but different VEGF isoforms may mediate distinct endothelial cell functions such as angiogenesis, vascular permeability, and differentiation. We sought to determine the effects of various VEGF isoforms on angiogenesis under ischemic conditions in rabbits.

METHODS

The effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development in ischemic rabbit hindlimb muscles were investigated by using naked plasmids encoding VEGF121 or VEGF165 (pVEGF121 or pVEGF165), either individually or in combination. pCMV beta was used as the control plasmid. The femoral artery on one side of New Zealand White rabbits was ligated. Ten days later, the ischemic muscles received direct intramuscular injection of pVEGF121 (500 micrograms), pVEGF165 (500 micrograms), or pVEGF121 (250 micrograms) + pVEGF165 (250 micrograms) in experimental groups, while pCMV beta (500 micrograms) was used in the control group. Therapeutic effects were evaluated 30 days later by anatomic and physiologic analysis.

RESULTS

Internal iliac angiography showed strong development of collateral circulation in all of the pVEGF-treated groups. In contrast, collateral arteries developed weakly in the control group. Combination treatment with both pVEGF121 and pVEGF165 did not result in additional improvement compared with pVEGF121 or pVEGF165 treatment alone (angiographic scores: pVEGF121 = 0.85 +/- 0.10; pVEGF165 = 0.81 +/- 0.11; pVEGF121 + pVEGF165 = 0.83 +/- 0.09; control = 0.53 +/- 0.09; p < 0.01). A favorable response in the development of circulation at the capillary level with pVEGF121 and/or pVEGF165 versus pCMV beta was also found. Blood pressure measurement and regional blood flow measurement using colored microspheres revealed similar results.

CONCLUSIONS

Our results show that direct intramuscular injection of naked DNA encoding VEGF121 or VEGF165, individually or in combination, is an effective method for gene transfer in an animal model of ischemic limbs and results in augmented collateral vascular development and tissue perfusion.

Genetic analysis of enterovirus 71 isolated from fatal and non-fatal cases of hand, foot and mouth disease during an epidemic in Taiwan, 1998

A large scale outbreak of hand-foot-and-mouth disease (HFMD) occurred in Taiwan in 1998, in which more than 80 children died of shock syndrome with pulmonary edema/hemorrhage. Enterovirus 71 was implicated as the cause of this outbreak. In order to understand the virological basis responsible for mortality on this scale, nucleotide sequences of VP1 that is important for serotypic specificity, and the 5'-non-coding region (5'-NCR) that is important for replication efficiency, were analyzed comparatively. Phylogenetic analysis of both VP1 and 5'-NCR of nine EV71 isolates derived from specimens of fatal patients and seven isolates derived from uncomplicated HFMD patients showed that all but one isolate fell into genotype B. The one distinct isolate from a case of uncomplicated HFMD belonged to genotype C that was clustered along with one isolate from Taiwan in 1986. Complete sequence analysis of two selected isolates, one from the spinal cord of a fatal case and one from the vesicle fluid of a patient with mild HFMD, confirmed a high degree (97-100%) of identity in nucleotide sequence throughout the entire genome, except focal regions of 3C and 3'-NCR where the nucleotide homology was 90-91%. The identity of the deduced amino acid sequence in the 3C region that encodes viral proteinase dropped further to 86%, a result of missense mutations at the first nucleotide position of many codons.

Impact of p53 status on heavy-ion radiation-induced micronuclei in circulating erythrocytes

Transgenic mice that differed in their p53 genetic status were exposed to an acute dose of highly charged and energetic (HZE) iron particle radiation. Micronuclei (MN) in two distinct populations of circulating peripheral blood erythrocytes, the immature reticulocytes (RETs) and the mature normochromatic erythrocytes (NCEs), were measured using a simple and efficient flow cytometric procedure. Our results show significant elevation in the frequency of micronucleated RETs (%MN-RETs) at 2 and 3 days post-radiation. At 3 days post-irradiation, the magnitude of the radiation-induced MN-RET was 2.3-fold higher in the irradiated p53 wild-type animals compared to the unirradiated controls, 2.5-fold higher in the p53 hemizygotes and 4.3-fold higher in the p53 nullizygotes. The persistence of this radiation-induced elevation of MN-RETs is dependent on the p53 genetic background of the animal. In the p53 wild-type and p53 hemizygotes, %MN-RETs returned to control levels by 9 days post-radiation. However, elevated levels of %MN-RETs in p53 nullizygous mice persisted beyond 56 days post-radiation. We also observed elevated MN-NCEs in the peripheral circulation after radiation, but the changes in radiation-induced levels of MN-NCEs appear dampened compared to those of the MN-RETs for all three strains of animals. These results suggest that the lack of p53 gene function may play a role in the iron particle radiation-induced genomic instability in stem cell populations in the hematopoietic system.

Dilatation of the biliary tree in children: sonographic diagnosis and its clinical significance

We evaluated sonographically 162 children who met the criteria for biliary tract dilatation in the past 18 years. Of these, 131 patients were diagnosed as having anomalous dilatations of the biliary tree (including 112 with choledochal cysts and 19 with biliary duct dilatation and biliary atresia). Biliary tract dilatations in the other 31 patients were due to secondary causes or normal variants. All cases of intrahepatic biliary tree dilatation and those with both intra- and extrabiliary duct dilatations were anomalous. In 117 cases of extrahepatic biliary tract dilatation only, the mean diameter was widest in cases of choledochal cyst (21.4 +/- 12.1 mm, compared with cases of biliary tract dilatation with biliary atresia (10 +/- 2.4 mm), secondary biliary duct dilatation (8.5 +/- 1.5 mm), and normal variants (4.4 +/- 1.2 mm) (P < 0.001). Of the 43 infants with biliary tree dilatation, 24 (56%) had choledochal cysts and 19 (44%) had biliary tract dilatation associated with biliary atresia. Excluding cases associated with biliary atresia, the accuracy of diagnosing choledochal cysts in extrahepatic biliary tract dilatation was 71% and 97% using cutoffs of 7 mm and 10 mm as the minimum diameter, respectively.

Effects of lead and noise exposures on hearing ability

Lead and noise, via different mechanisms, may damage hearing ability, and, in some cases, cause severe and irreversible damage. To explore possible independent and synergistic effects of lead and noise on auditory function, the authors conducted a cross-sectional study in two lead-battery manufacturing factories. Lead and noise were the two most common sources of occupational exposures in the factories. Blood lead level, ambient lead concentration, noise exposure level, and hearing thresholds of 339 lead-battery workers-including clerical and managerial staffs-were measured. The authors obtained demographics and working histories via an interview-based structured questionnaire. A total of 220 lead-battery workers were exposed to high levels of lead and noise; their average blood lead concentration was 56.9 microg/dl, and their average noise exposure level was 86.0 dBALeq. Multivariate analysis, in which possible risk factors of hearing ability were considered, demonstrated a significant correlation between a high, long-term lead exposure index (defined by duration of employment and ambient lead concentration) and decreased hearing ability. In contrast, such a correlation between short-term lead exposure (defined by blood lead level) and hearing ability was not significant. Furthermore, neither noise exposure level alone nor the interaction between noise exposure level and short- or long-term lead exposure was correlated significantly with hearing ability. The present study raises an important, but typically ignored, issue: lead exposure might precipitate a more severe auditory than noise-exposure effect. The preservation of workers' hearing ability requires that preventive measures be taken against noise exposure, which is as essential as measures taken against lead exposure.