A Molecular Approach to Characterize the Effects of Fluence, Fluence Rate and LET on Radiation Damage

PURPOSE/OBJECTIVE(S)

Effects of fluence, fluence rate and LET on radiation damage are not resolved using traditional methods of measuring energy deposited by ionization events. The deficiency led to the use of empirical RBE factors in the clinical applications of particle therapy. The use of ionization dosimetry is similarly challenged when applied to development of radiation treatment at ultrahigh (FLASH) dose rate. This study reports a molecular method using plasmid DNA as a more comprehensive model for radiation dosimetry than ionization measurements.

MATERIALS/METHODS

Aqueous solutions of purified supercoiled plasmid DNA, pUC19 (2686 bp), were prepared at different scavenging conditions and injected into 5x5x1 mm3 wells as detector elements. Irradiated samples were analyzed using base excision repair enzymes (Nth and Fpg) and gel electrophoresis to measure yields for DNA single and double strand breaks (SSB and DSB), and clustered lesions. The low LET characteristics of conventional radiation treatment was modeled using orthovoltage 150 kVp x-rays to deliver 2-110 Gy at 90 and 0.5 Gy/s. Higher LET irradiations in the range of 2 - 14 keV/μm were facilitated by measurements in the pristine Bragg peak region using synchrotron-produced 142.2 MeV protons to deliver dose at 2 - 160 Gy at 600 and 1 Gy/s. The DNA wells were inserted into a solid water equivalent phantom for proton irradiation. Only 4 wells could be positioned in the short Bragg peak region in water (∼ 2 cm). To alleviate the uncertainties due to rapidly varying dose and LET distributions, we innovated the use of a 3% water density (i.e., Styrofoam) medium to extend the Bragg peak region from 2 cm to 20 cm, enabling the placement of 20 well containers.

RESULTS

Quantity and quality of molecular damage in the plasmid DNA model varies with fluence, fluence rate and LET of radiation. At high fluence (> 30 Gy) of low-LET radiations, the yields of DNA SSB and non-DSB clustered lesions depend on the fluence rate. These yields decrease by two times between ultrahigh and conventional dose rate irradiation. At a given fluence and fluence rate, the yields for the formation of DNA DSB and non-DSB clustered lesions increase linearly with LET. The low-density phantom allows significant (∼ 10 folds) increase in the number of sampling points and more accurate sample positioning at specific LET compared to water-equivalent phantom. Monte-Carlo track structure simulation of yields for different DNA lesions is being developed to model the molecular damage. In parallel, approaches to improve the sensitivity of the measurements to dose are being investigated.

CONCLUSION

Our results suggest that a molecular-based approach can be used to differentiate the effects of fluence, fluence rate, and LET on radiation damage. The approach demonstrates the potential to improve on the modeling of radiation effects in biological systems than using measured ionization energy. Correlation of the molecular changes to biological outcome for in vitro and in vivo systems are under investigation.

Cellular uptake and anti-inflammatory effects of palm oil-derived delta (δ)-tocotrienol in microglia

Tocopherols long dominated studies on vitamin E, although interest has shifted to tocotrienols. It was previously shown that δ-tocotrienol derived from palm oil reduced nitric oxide released by BV2 microglia as early as 18 h after lipopolysaccharide stimulation. The current study measured δ-tocotrienol uptake by BV2 over a 24 h incubation period and its anti-inflammatory effects on primary microglia. Uptake of 17.5 μg/mL δ-tocotrienol by BV2 microglia began as early as 5 min and rose steeply to 21 ± 3% of the amount administered at 24 h. The amount of δ-tocotrienol retained in the lipopolysaccharide-stimulated microglia at 24 h was 14 ± 2%, with no substantial difference seen in unstimulated microglia. The same δ-tocotrienol regimen reduced nitric oxide levels by 82% at 24 h after lipopolysaccharide stimulation (p < 0.05). This was accompanied by decreased inducible nitric oxide synthase protein expression by 67 ± 5% compared to untreated controls (p < 0.05). In primary microglia, δ-tocotrienol downregulated IL-1β production, but TNF-α and IL-6 were not affected. δ-Tocotrienol also reduced prostaglandin E2 production by ~78%% and decreased transcription of COX-2 and 5-LOX, but not COX-1. This study showed the anti-inflammatory effects of δ-tocotrienol derived from palm oil and opens up interest for tocotrienol supplementation to reduce the effects of inflammatory conditions.

A randomized single-dose, two-period crossover bioequivalence study of two fixed-dose Paracetamol/Orphenadrine combination preparations in healthy volunteers under fasted condition

BACKGROUND

Paracetamol/Orphenadrine is a fixed dose combination containing 35 mg orphenadrine and 450 mg paracetamol. It has analgesic and muscle relaxant properties and is widely available as generics. This study is conducted to investigate the relative bioavailability and bioequivalence between one fixed dose paracetamol/orphenadrine combination test preparation and one fixed dose paracetamol/orphenadrine combination reference preparation in healthy volunteers under fasted condition for marketing authorization in Malaysia.

METHOD

This is a single-center, single-dose, open-label, randomized, 2-treatment, 2-sequence and 2-period crossover study with a washout period of 7 days. Paracetamol/Orphenadrine tablets were administered after a 10-h fast. Blood samples for pharmacokinetic analysis were collected at scheduled time intervals prior to and up to 72 h after dosing. Blood samples were centrifuged, and separated plasma were kept frozen (- 15 °C to - 25 °C) until analysis. Plasma concentrations of orphenadrine and paracetamol were quantified using liquid-chromatography-tandem mass spectrometer using diphenhydramine as internal standard. The pharmacokinetic parameters AUC0-∞, AUC0-t and Cmax were determined using plasma concentration time profile for both preparations. Bioequivalence was assessed according to the ASEAN guideline acceptance criteria for bioequivalence which is the 90% confidence intervals of AUC0-∞, AUC0-t and Cmax ratio must be within the range of 80.00-125.00%.

RESULTS

There were 28 healthy subjects enrolled, and 27 subjects completed this trial. There were no significant differences observed between the AUC0-∞, AUC0-t and Cmax of both test and reference preparations in fasted condition. The 90% confidence intervals for the ratio of AUC0-t (100.92-111.27%), AUC0-∞ (96.94-108.08%) and Cmax (100.11-112.50%) for orphenadrine (n = 25); and AUC0-t (94.29-101.83%), AUC0-∞ (94.77-101.68%) and Cmax (87.12-101.20%) for paracetamol (n = 27) for test preparation over reference preparation were all within acceptable bioequivalence range of 80.00-125.00%.

CONCLUSION

The test preparation is bioequivalent to the reference preparation and can be used interchangeably.

TRIAL REGISTRATION

NMRR- 17-1266-36,001; registered and approved on 12 September 2017.

Efficacy of Oral Mixed Tocotrienols in Diabetic Peripheral Neuropathy: A Randomized Clinical Trial

Importance

Management of painful diabetic peripheral neuropathy remains challenging. Most therapies provide symptomatic relief with varying degrees of efficacy. Tocotrienols have modulatory effects on the neuropathy pathway and may reduce neuropathic symptoms with their antioxidative and anti-inflammatory activities.

Objective

To evaluate the efficacy of oral mixed tocotrienols for patients with diabetic peripheral neuropathy.

Design, Setting, and Participants

The Vitamin E in Neuroprotection Study (VENUS) was a parallel, double-blind, placebo-controlled trial that recruited participants from January 30, 2011, to December 7, 2014, with 12 months of follow-up. This trial screened 14 289 patients with diabetes from 6 health clinics and ambulatory care units from 5 public hospitals in Malaysia. A total of 391 patients who reported neuropathic symptoms were further assessed with Total Symptom Score (TSS) and Neuropathy Impairment Score (NIS). Patients 20 years or older with a TSS of 3 or higher and an NIS of 2 or higher were recruited.

Interventions

Patients were randomized to receive 200 mg of mixed tocotrienols twice daily or matching placebo for 12 months. Patients with hyperhomocysteinemia (homocysteine level ≥2.03 mg/L) received oral folic acid, 5 mg once daily, and methylcobalamin, 500 μg thrice daily, in both groups.

Main Outcomes and Measures

The primary outcome was patient-reported neuropathy TSS (lancinating pain, burning pain, paresthesia, and asleep numbness) changes at 12 months. The secondary outcomes were NIS and sensory nerve conduction test result.

Results

Of 391 eligible patients, 300 were recruited (130 [43.3%] male; mean [SD] age, 57.6 [8.9] years; mean [SD] duration of diabetes, 11.4 [7.8] years) and 229 (76.3%) completed the trial. The TSS changes between the tocotrienols and placebo groups at 12 months (-0.30; 95% CI, -1.16 to 0.56; P = .49) were similar. No significant differences in NIS (0.60; 95% CI, -1.37 to 2.65; P = .53) and sensory nerve conduction test assessments were found between both groups. In post hoc subgroup analyses, tocotrienols reduced lancinating pain among patients with hemoglobin A1C levels greater than 8% (P = .03) and normohomocysteinemia (homocysteine level <2.03 mg/L; P = .008) at 1 year. Serious adverse events in both groups were similar, except more infections were observed in the tocotrienols group (6.7% vs 0.7%, P = .04). Results reported were of modified intention-to-treat analyses.

Conclusions and Relevance

Supplementation of oral mixed tocotrienols, 400 mg/d for 1 year, did not improve overall neuropathic symptoms. The preliminary observations on lancinating pain among subsets of patients require further exploration.

Trial Registration

National Medical Research Registry Identifier: NMRR-10-948-7327 and clinicaltrials.gov Identifier: NCT01973400.

State of the art of high energy photon treatment planning

A virtual revolution in computer capability has occurred in the last few years, based largely on rapidly decreasing costs and increasing reliability of digital memory and mass-storage capability. These developments have now made it possible to consider the application of both computer and display technologies to a much broader range of problems in radiation therapy including dose computation, therapy planning and treatment verification. Various similar methods of three-dimensional dose computations in heterogeneous media capable of 2-3% accuracy are likely to be available, but significant work still remains especially for high energy X-rays where electron transport, and possibly pair production, needs to be considered. Innovative display and planning techniques are emerging and show great promise for the future. No doubt these advances will lead to substantially improved treatment planning systems in the next few years. However, it must be emphasized that for many of these applications a tremendous software and hardware development effort is required. Yet it is not clear whether the investments and efforts for improved capabilities and accuracies are warranted with respect to clinical outcome. The question must be addressed for the advancement in the practice of radiotherapy.

Sex pheromone components of fall cankerworm moth,Alsophila pometaria : Synthesis and field trapping

(Z,Z,Z,E)-3,6,9,11-Nonadecatetraene and (Z,Z,Z,Z)-3,6,9,11-nonadecatetraene, sex pheromone components ofAlsophila pometaria, were synthesized by stereoselective Wittig reactions and found to be spectroscopically and chromatographically identical to isolated natural material. Flight-tunnel bioassays and field-trapping experiments confirmed that the two tetraenes together with (Z,Z,Z)-3,6,9-nonadecatriene are sex pheromone components. While traps baited with either tetraene individually captured conspecific males in field-trapping experiments, addition of the triene, which captured no males by itself, to either tetraene resulted in synergistic responses.

Attraction of tortricid moths of subfamily olethreutinae to field traps baited with dodecadienes

All four geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups were synthesized and field tested. The field survey produced sex attractant lures for 14 insect species. Species in the generaCydia, Grapholita, Eucosma, Pelochrista, Petrova, Phenta, Hedya, and Pseudosciaphila were captured. Defined lures were developed for some of the species captured. Gas chromatographie retention times for all geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups are reported. A study of the isomerization of 8,10-dodecadienyl acetates and aldehydes impregnated in rubber septa is reported.

Sex attractants for Geometrid and Noctuid moths : Field trapping and electroantennographic responses to triene hydrocarbons and monoepoxydiene derivatives

Male moths belonging to 17 species of Geometridae and nine species of Noctuidae were captured in traps baited with synthetic chemicals as part of a field screening program. The compounds tested were the C18-C22 homologs of: (1) (3Z,6Z,9Z)-triene hydrocarbons; (2) mixtures containing equal quantities of (3Z,6Z)-cis-9,10-expoxydienes, (3Z,92Z)-cis-6,7-epoxydienes, and (6Z,9Z)-cis-3,4-epoxydienes; (3) (3Z,6Z)-9S,10R-epoxydienes; (4) (3Z,6Z)-9R,10S-epoxydienes; and (5) (3Z,6Z,9Z,11E)-nonadecatetraene. Field captures and electroantennographic assays revealed a high degree of specificity in the responses of many species to the synthetic chemicals. In several species the ability of males to discriminate between the 9S,10R and 9R,10S enantiomers of the monoepoxydiene isomers was clearly shown. Synergists and inhibitors were discovered for several of the reported attractants, some of which were not previously known to have semiochemical activity. The geometrid moths captured includedEpirrhoe sperryi (Herbulot),Mesoleuca ruficillata (Guenée),Triphosa haesitata (Guenée),Metanema inatomaria (Guenée),Prochoerodes transversata (Drury),Cabera erythemaria (Guenée),Synaxis jubararia (Hulst),Dysstroma brunneata ethela (Hulst),Eulithes testata (Linnaeus),Sicya macularia (Harris),Xanthorhoe iduata (Guenée),X. abrasaria aquilonaria (Herrich-Schäffer),X. munitata (Hübner),Itame loricaria (Eversmann),Eupithecia annulata (Hulst),E. rovocastaliata (Packard) andE. satyrata dodata (Taylor). The noctuid moths captured includedBleptina caradrinalis (Guenée),Idia américalis (Guenée),I. aemula (Hübner),Rivula propinqualis (Guenée),Lomanaltes eductalis (Walker),Spargaloma sexpunctata (Grote),Caenurgina distincta (Neumuller),Euclidia cuspidea (Hübner), andZale duplicata (Bethune). Six of the nine noctuid species captured belong to three subfamilies for which sex attractants had not been reported previously. Details for the stereospecific synthesis of (3Z,6Z)-cis-9,10-epoxydienes are also reported.

Use of a sex attractant and an inhibitor for monitoring winter moth and bruce spanworm populations

A single sex pherormone component was isolated from abdominal tip extracts of female Bruce spanworm.Operophtera bruceata (Hulst). This was identified as (Z,Z,Z)-1,3,6,9-nonadecatetraene by capillary gas chromatography (GC), electroantennography, and mass spectrometry. In addition, hexane extracts of female abdominal tips from Bruce spanworm and the winter moth.O. brumata L., were analyzed by GC coupled to an electroantennographic detector (GC-EAD). The extracts ofO. bruceata andO. brumata females elicited only a single response, at the same retention time, from antennae of their conspecific and reciprocal males. In field tests conducted in Saskatchewan, traps baited with the synthetic tetraene captured Bruce spanworm males. In tests carried out on Vancouver Island, British Columbia, where the two species coexist, both Bruce spanworm and winter moth males were captured. The attractancy of lures containing the synthetic pheromone alone and in combination with several structurally related analogs was field tested at both locations. One of these, an isomer of the natural pheromone, (E,Z,Z)-1,3,6,9-nonadecatetraene, inhibited the capture of Bruce spanworm males but had no effect upon the number of winter moth males which were taken. Thus, populations of these two very similar species can be distinguished by employing traps baited with pheromone ± the inhibitor. Coneorifice Hara traps were found useful for field trapping males of both species.

Long-term results of screening with magnetic resonance imaging in women with BRCA mutations

Background:

The addition of breast magnetic resonance imaging (MRI) to screening mammography for women with BRCA mutations significantly increases sensitivity, but there is little data on clinical outcomes. We report screening performance, cancer stage, distant recurrence rate, and breast cancer-specific mortality in our screening study.

Methods:

From 1997 to 2009, 496 women aged 25 to 65 years with a known BRCA1/2 mutation, of whom 380 had no previous cancer history, were enrolled in a prospective screening trial that included annual MRI and mammography.

Results:

In 1847 screening rounds, 57 cancers were identified (53 screen-detected, 1 interval, and 3 incidental at prophylactic mastectomy), of which 37 (65%) were invasive. Sensitivity of MRI vs mammography was 86% vs 19% over the entire study period (P<0.0001), but was 74% vs 35% from 1997 to 2002 (P=0.02) and 94% vs 9% from 2003 to 2009 (P<0.0001), respectively. The relative sensitivities of MRI and mammography did not differ by mutation, age, or invasive vs non-invasive disease. Of the incident cancers, 97% were Stage 0 or 1. Of 28 previously unaffected women diagnosed with invasive cancer, 1 BRCA1 mutation carrier died following relapse of a 3 cm, node-positive breast cancer diagnosed on her first screen at age 48 (annual breast cancer mortality rate=0.5%). Three patients died of other causes. None of the 24 survivors has had a distant recurrence at a median follow-up of 8.4 years since diagnosis.

Conclusion:

Magnetic resonance imaging surveillance of women with BRCA1/2 mutations will detect the majority of breast cancers at a very early stage. The absence of distant recurrences of incident cancers to date is encouraging. However, longer follow-up is needed to confirm the safety of breast surveillance.

Effect of Mixed-Tocotrienols in Hypercholesterolemic Subjects

Background: Studies on the cholesterol lowering activity of tocotrienols have yielded mixed results, with some showing cholesterol lowering effect while some showing no activity.Aim: A randomized, double-blind, parallel group study was conducted to investigate the cholesterol lowering activity of tocotrienols. Methods: Thirty-two hypercholesterolemic subjects were randomly assigned to orally receive either 300 mg of mixed tocotrienols capsules daily or placebo capsules containing 300 mg of soya bean oil for a period of 6 months. The subjects were monitored before supplementation and monthly thereafter for their serum cholesterol as well as tocotrienol and tocopherol concentrations.Results: The serum total cholesterol and low density lipoprotein (LDL) cholesterol of the subjects in the tocotrienol supplementation group were decreased significantly by -8.9 ± 0.9% and -12.8 ± 2.6% respectively after 4 months of supplementation and the reduction persisted till the end of the 6-month study, with a reduction of -10.8 ± 1.0% and  -17.3 ± 1.8%, respectively from baseline. Moreover, there was a 22-fold increase in the total tocotrienol concentrations from baseline during supplementation compared to the placebo group, while the concentration of α-tocopherol recorded only a modest increase. On the other hand, the serum cholesterol, total tocotrienol and α-tocopherol concentrations of subjects in the placebo group remained essentially unchanged.Conclusions: Supplementation with mixed tocotrienols at dose of 300 mg per day resulted in the lowering of the serum total and LDL cholesterol levels after 5 months of supplementation.Keywords: tocotrienols, cholesterol-lowering, total cholesterol, LDL cholesterol, tocopherols

Prevalence of non-alcoholic fatty liver in a hypercholesterolemic population of northwestern peninsular Malaysia

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and a frequent finding on ultrasound examination. NAFLD is considered as the liver component of metabolic syndrome and is linked to accelerated atherosclerosis and cardiovascular disease. No data from systematic studies regarding the prevalence of NAFLD are available for the Malaysian population. One hundred eighty untreated hypercholesterolemic volunteers underwent blood and ultrasound examinations to evaluate their livers. NAFLD was diagnosed in 102 subjects (56.7%) with similar prevalences between sexes. Of the 102 positive subjects 82 (80.4%) were graded as mild, 17 (16.7%) as moderate and 3 (2.9%) as severe fatty liver cases. Elevated fasting plasma glucose (FPG) levels were found in 13 of 180 subjects (7.2%), while elevated AST and ALT levels were seen in 30 (16.7%) and 22 (12.2%) of the180 subjects, respectively.

A comprehensive system for dosimetric commissioning and Monte Carlo validation for the small animal radiation research platform

Our group has constructed the small animal radiation research platform (SARRP) for delivering focal, kilo-voltage radiation to targets in small animals under robotic control using cone-beam CT guidance. The present work was undertaken to support the SARRP's treatment planning capabilities. We have devised a comprehensive system for characterizing the radiation dosimetry in water for the SARRP and have developed a Monte Carlo dose engine with the intent of reproducing these measured results. We find that the SARRP provides sufficient therapeutic dose rates ranging from 102 to 228 cGy min(-1) at 1 cm depth for the available set of high-precision beams ranging from 0.5 to 5 mm in size. In terms of depth-dose, the mean of the absolute percentage differences between the Monte Carlo calculations and measurement is 3.4% over the full range of sampled depths spanning 0.5-7.2 cm for the 3 and 5 mm beams. The measured and computed profiles for these beams agree well overall; of note, good agreement is observed in the profile tails. Especially for the smallest 0.5 and 1 mm beams, including a more realistic description of the effective x-ray source into the Monte Carlo model may be important.

Drug-polymer mixed coating: a new approach for controlling drug release rates in pellets

A new approach to developing a drug-polymer mixed coat for highly water-soluble diltiazem pellets was investigated at different coating levels. Drug layering and the coating procedures were performed using a bottom spray fluidized bed coater. Drug pellets were coated with Eudragit NE40 (NE40) alone and in combination with diltiazem and hydrophilic cellulose derivatives. Dissolution studies revealed that incorporation of hydrophilic substances such as methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), and the drug itself considerably increased the release rates. The release from mixed polymer coatings was fast compared to pellets coated with NE40 only. The major portion of the drug was released in about 2 hours in case of MC and NE40 mixed coat compared to hours from coated pellets containing HPMC or diltiazem. Incorporation of 15% to 25% drug with respect to the polymer coat helped to achieve a drug-release profile at a desirable rate over a 12 hour period. Moreover, the test formulation comprising 25% diltiazem with respect to 7% NE40 had a dissolution profile that matched the commercial product, Herbesser SR capsules. The release of diltiazem from the coated pellets was slightly affected by the pH of dissolution media.

Determination of flavonoids from Orthosiphon stamineus in plasma using a simple HPLC method with ultraviolet detection

A simple liquid chromatographic method was developed for the simultaneous determination of flavonoids from Orthosiphon stamineus Benth, namely sinensitin, eupatorin and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone, in plasma. Prior to analysis, the flavonoids and the internal standard (naproxen) were extracted from plasma samples using a 1:1 mixture of ethyl acetate and chloroform. The detection and quantification limits for the three flavonoids were similar being 3 and 5 ng/ml, respectively. The within-day and between-day accuracy values, expressed as percentage of true values, for the three flavonoids were between 95 and 107%, while the corresponding precision, expressed as coefficients of variation, for the three flavonoids were less than 14%. In addition, the mean recovery values of the extraction procedure for all the flavonoids were between 92 and 114%. The calibration curves were linear over a concentration range of 5-4000 ng/ml. The present method was applied to analyse plasma samples obtained from a pilot study using rats in which the mean absolute oral bioavailability values for sinensitin, eupatorin and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone was 9.4, 1.0 and 1.5%, respectively.

Liquid chromatographic method for the determination of plasma itraconazole and its hydroxy metabolite in pharmacokinetic/bioavailability studies

A sensitive and selective high-performance liquid chromatographic method was developed for the determination of itraconazole and its active metabolite, hydroxyitraconazole, in human plasma. Prior to analysis, both compounds together with the internal standard were extracted from alkalinized plasma samples using a 3:2 (v/v) mixture of 2,2,4-trimethylpentane and dichloromethane. The mobile phase comprised 0.02 M potassium dihydrogen phosphate-acetonitrile (1:1, v/v) adjusted to pH 3.0. Analysis was run at flow-rate of 0.9 ml/min with excitation and emission wavelengths set at 260 and 365 nm, respectively. Itraconazole was found to adsorb on glass or plastic tubes, but could be circumvented by prior treating the tubes using 10% dichlorodimethylsilane in toluene. Moreover, rinsing the injector port with acetonitrile helped to overcome any carry-over effect. This problem was not encountered with hydroxyitraconazole. The method was sensitive with limit of quantification of 3 ng/ml for itraconazole and 6 ng/ml for hydroxyitraconazole. The calibration curve was linear over a concentration range of 2.8-720 ng/ml for itraconazole and 5.6-720 ng/ml for the hydroxy metabolite. Mean recovery value of the extraction procedure for both compounds was about 85%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 15%. Hence, the method is suitable for use in pharmacokinetic and bioavailability studies of itraconazole.

Comparative bioavailability study of a generic sustained release diclofenac sodium tablet

The bioavailability of a generic diclofenac sodium sustained release tablet preparation (Zolterol, SR) was compared with the innovator product, Voltaren, SR. Twelve healthy adult male volunteers participated in the study, which was conducted according to a randomized, two-way crossover design with a wash out period of one week. The bioavailability of diclofenac was compared using the parameters area under the plasma concentration-time curve (AUC(0-infinity)), peak plasma concentration (Cmax) and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed for both logarithmically transformed AUC(0-infinity), Cmax values and Tmax value of the two preparations.

Inclusion Complexation of Artemisinin with α-, β-, andγ-Cyclodextrins

The present study was conducted to investigate the inclusion complexation of artemisinin (ART) with natural cyclodextrins (CyD), namely alpha-, beta-, and gamma-CyDs with the aim of improving its solubility and dissolution rate. Complex formation in aqueous solution and solid state was studied by solubility analysis, dissolution, and thermal analysis. Solubility diagrams indicated that the complexation of ART and the three CyDs occurred at a molar ratio of 1:1, and showed a remarkable increase in ART solubility. Moreover, the thermodynamic parameters calculated by using the van't Hoff equation revealed that the complexation process was associated with negative enthalpy of formation and occurred spontaneously. The complexation capability of CyDs with ART increased in the order of alpha- < gamma- < beta-CyDs and could be ascribed to the structural compatibility between the molecular size of ART and the diameter of the CyD cavities. Dissolution profiles of the three complexes demonstrated an increased rate and extent of dissolution compared with those of their respective physical mixtures and a commercial preparation. In solid-state analysis, using differential scanning calorimetry, the gamma-CyD was capable of complexing the highest percentage of ART, followed by beta- and alpha-CyDs. The respective estimated percentage of ART complexed by the CyDs were 85%, 40%, and 12%.

Aluminium and fluoride concentrations of three tea varieties growing at Lantau Island, Hong Kong

The present project aims to investigate aluminium (Al) and fluoride (F) contents in teas (Camellia sinensis (L.) O. Kuntze). Three different commercial tea varieties: Assam variety and two China sub-varieties, a large leafed variety and small leafed variety, were collected in two tea gardens of Lantau Island tea plantation of Hong Kong. In general, high concentrations of Al and F were accumulated in the mature leaves (15.3 and of 2.07 g kg-1 respectively). Among the three varieties, 'the small leafed' variety exhibited the highest Al and F contents followed by the 'large leafed' variety whereas the Assam variety had the lowest Al and F concentrations in its tea bushes. Tea products from a plantation were also analysed and it was noted that black tea had higher Al and F concentrations than green tea. The amount of Al and F released into tea liquor was also tested and the results showed that higher concentrations of Al and F were released into tea liquor under repeated infusion method than continuous infusion method.

Therapeutic equivalence of a low dose artemisinin formulation in falciparum malaria patients

We have evaluated the therapeutic equivalence of a beta-cyclodextrin-artemisinin complex at an artemisinin dose of 150 mg, with a commercial reference preparation, Artemisinin 250 at a recommended dose of 250 mg. One hundred uncomplicated falciparum malarial patients were randomly assigned to orally receive either beta-cyclodextrin-artemisinin complex (containing 150 mg artemisinin) twice daily for five days or the active comparator (containing 250 mg artemisinin) twice daily for five days. The patients were hospitalized for seven days and were required to attend follow up assessments on days 14, 21, 28 and 35. All patients in both treatment groups were cured of the infection and achieved therapeutic success. At day seven of treatment, all patient blood was clear of the parasites and the sublingual temperature of all patients was less than 37.5 degrees C. Moreover, the parasite clearance time in both treatment groups was similar, being approximately three days after initiation of treatment. Comparable plasma artemisinin concentrations were observed between patients in both treatment groups at 1.5 and 3.0 h, although slightly higher levels were obtained with patients in the beta-cyclodextrin-artemisinin complex-treated group. The beta-cyclodextrin-artemisinin complex at a dose of 150 mg artemisinin was therapeutically equivalent to 250 mg Artemisinin 250. Additionally, patients receiving beta-cyclodextrin-artemisinin complex showed less variability in their plasma artemisinin concentrations at 1.5 h post-dosing, which suggested a more consistent rate of drug absorption.

A performance comparison of flat-panel imager-based MV and kV cone-beam CT

The use of cone-beam computed tomography (CBCT) has been proposed for guiding the delivery of radiation therapy, and investigators have examined the use of both kilovoltage (kV) and megavoltage (MV) x-ray beams in the development of such CBCT systems. In this paper, the inherent contrast and signal-to-noise ratio (SNR) performance for a variety of existing and hypothetical detectors for CBCT are investigated analytically as a function of imaging dose and object size. Theoretical predictions are compared to the results of experimental investigations employing largearea flat-panel imagers (FPIs) at kV and MV energies. Measurements were performed on two different FPI-based CBCT systems: a bench-top prototype incorporating an FPI and kV x-ray source (100 kVp x rays), and a system incorporating an FPI mounted on the gantry of a medical linear accelerator (6 MV x rays). The SNR in volume reconstructions was measured as a function of dose and found to agree reasonably with theoretical predictions. These results confirm the theoretically predicted advantages of employing kV energy x rays in imaging soft-tissue structures found in the human body. While MV CBCT may provide a valuable means of correcting 3D setup errors and may offer an advantage in terms of simplicity of mechanical integration with a linear accelerator (e.g., implementation in place of a portal imager), kV CBCT offers significant performance advantages in terms of image contrast and SNR per unit dose for visualization of soft-tissue structures. The relatively poor SNR performance at MV energies is primarily a result of the low x-ray quantum efficiencies (approximately a few percent or less) that are currently achieved with FPIs at high energies. Furthermore, kV CBCT with an FPI offers the potential of combined volumetric and radiographic/fluoroscopic imaging using the same device.

Effect of applying Hong Kong biosolids and lime on nutrient availability and plant growth in an acidic loamy soil

A greenhouse experiment was conducted to evaluate the growth of Brassica chinensis L. in an acidic loamy soil amended with municipal biosolids with or without lime treatment (750 mg kg(-1)). The soil was amended with one of two municipal biosolids from Tai Po (TP) or Yuen Long (YL) wastewater treatment plants at application rates of 0, 5, 10, 25 and 50% (v/v). Initial NH(+)4-N and PO(3-)4-P concentrations in the amended soil increased with an increase in municipal biosolids loading rates and those with biosolids from TP had a greater increase in nutrients than those from YL. However, initial NO(-)3-N contents in both municipal biosolids amended soils decreased with an increase in biosolids loading rates, particularly for the soil amended with YL. Soluble K, Mg, Na and Ca concentrations in the soil increased with application rates. Municipal biosolids amended soil without lime treatment had higher NH(+)4-N, NO(-)3-N and major cation contents than those with lime. Addition of Tai Po municipal biosolids and lime significantly increased the dry weight yields of B. chinensis L., while YL municipal biosolids increased yields only at the 5% rate with lime amendment. The maximum growth was obtained at municipal biosolids application rates of 5 and 10% for TP and 5% for YL for limed soil. Addition of municipal biosolids increased the total N, P, Zn, Cr and major cation concentrations in the shoot tissue, while lime treatment reduced Zn and Cr contents. The high salt and metal concentrations would likely be factors inhibiting plant growth at high application rates, especially for YL biosolids. Further studies to determine the long-term effects of biosolid application on soil and crop quality are warranted.

Toxicity evaluation of sewage sludges in Hong Kong

Anaerobically digested sewage sludges collected from four wastewater treatment plants located in Sha Tin, Tai Po, Yuen Long, and Shek Wu Hui in Hong Kong were subjected to chemical characterization and toxicity testing to provide preliminary assessment of their suitability for land application. All sewage sludges were slightly alkaline with pH range of 8.3-8.7. Electrical conductivity (EC; 0.69 dS m(-1)) and soluble NH4-N content (996 mg kg(-1)) of sewage sludge from Yuen Long were lower than that of other plants. Concentrations of heavy metals were determined as total, extractable, and water-soluble fraction using mixed acid digestion, DTPA (pH 7.3), and distilled water, respectively. Yuen Long sludge was most polluted with Zn and Cr higher than the pollutant concentration limits listed in Part 503 of USEPA, owing to the effluent coming from the tannery industry. High concentration of Ni was found in sludge from Sha Tin that originated mainly from the electroplating industry. DTPA-extractable Zn contents were high in sludges from Yuen Long (1247 mg kg(-1)) and Shek Wu Hui (892 mg kg(-1)), while 3.7 mg kg(-1) of DTPA-extractable Cr was found in Yuen Long sludge. Metal speciation of sludges showed that Pb was major in residual phase while Cu, Cr, and Ni in organic and residual phases, and Zn did not show any dominant chemical phase. The sludge extracts did not exert significant adverse effect on seed germination of Brassica chinensis (Chinese cabbage), but Yuen Long sludge caused a reduction in root growth. In view of its lower EC and soluble ammonia contents, the high concentration of Zn and Cr in Yuen Long sludge would likely be responsible for this adverse effect on root growth. Therefore, Yuen Long sludge would likely have a more serious impact on soil quality and plant growth as compared to other sludges. This would require further verification from greenhouse and field experiments.

Implementing multiple static field delivery for intensity modulated beams

A clinically oriented two-dimensional intensity-modulated beam delivery method is implemented using multiple static segmented fields, i.e., the "step-and-shoot" approach. Starting with a desired al" intensity distribution, it creates a multiple-level intensity approximation, and then constructs a sequence of segmented fields to deliver the multiple-level intensities using multileaf collimator (MLC) and independent backup jaws. The approach starts with a simple grouping of all the nonzero intensity values into a minimum number of clusters for a user specified deviation tolerance for the ideal plan. The k-means clustering algorithm is then employed to find the optimal levels of intensity that minimize the discrepancies between the ideal and the approximated intensities, without violating the user specified deviation tolerance. The multiple-level intensities are then decomposed into a sequence of machine deliverable segments. Apart from the first segment for each gantry angle, all the other segments are arranged to minimize the total travel distance of the leaves. The first segment covers the entire irradiated area and is used for treatment verification by electronic portal imaging. The implementation issues due to the physical constraints of the MLCs are also addressed.

Improved oral bioavailability of artemisinin through inclusion complexation with beta- and gamma-cyclodextrins

The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-infinity)), peak plasma concentration (C(max)), and time to reach peak plasma concentration (T(max)). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma-cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-infinity) values of the beta-cyclodextrin complex over those of Artemisinin 250 was estimated to be between 1.51-2.04, while that of C(max) was between 1.73-2.93. For the gamma-cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma-cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250. In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract.

Nitrogen transformations during pig manure composting

Composting is now suggested as one of the environmentally and friendly alternative method for disposal of solid organic wastes, as it leads to minimization, stabilization, and utilization of organic waste. Transformations of nitrogen were investigated in co-composting of pig manure with different amendments, such as sawdust and leaves. Samples were analyzed for pH, total-N, soluble NH4-N, soluble NO3-N and soluble organic-N. The total-N increased after 63 days of composting, as well as the soluble NO3-N and soluble organic-N. Soluble NH4-N increased significantly and showed peak values at day 7, thereafter decreased sharply and gradually to lower levels. Seed germination index (GI) showed that co-composting of pig manure with sawdust reached maturity after 49 days of composting, while co-composting of pig manure with sawdust and leaves required shorter time for 35 days. Soluble NH4-N was significantly negatively (P < 0.05), while soluble NO3-N and soluble organic-N were significantly positively (P < 0.05), correlated with seed germination index (GI). Addition of leaves in co-composting of pig manure with sawdust had no significant impacts on nitrogen transformations, but it was beneficial for maturity of pig manure compost.

Persistency of bacterial indicators in biosolids stabilization with coal fly ash and lime

Alkaline coal fly ash and lime were tested for their effectiveness in pathogen removal from biosolids at different time intervals and temperatures. Coal fly ash at 10 and 35% w/w was mixed with dewatered biosolids and then the ash-biosolids mixture was mixed separately with 0, 1.1, 2.2, 4.4, 8.5, 11, and 18% calcium oxide (w/w on a dry weight basis) with and without heating to 55 degrees C. Total bacteria, salmonella, and total coliforms were monitored at various time intervals. Both ash-biosolids mixtures with or without lime amendment had a significantly lower total bacterial population than the biosolids control, but the residual indigenous bacterial flora in the ash and lime stabilized biosolids still maintained a population of greater than 10(4) g(-1) dry biosolids. Alkaline-stabilized biosolids with a lime amendment rate greater than 8.5% could maintain pH greater than or equal to 12 for more than 2 hours, which effectively removed total coliforms and salmonella in the mixture. Heat treatment to 55 degrees C and a storage time of 14 days provided an added advantage resulting in a further reduction in pathogens for all treatments. It is recommended that 10% ash-biosolids mixture should be amended with a minimum of 8.5% lime on a dry weight basis for at least 2 hours to achieve acceptable levels of salmonella and total coliforms to ensure no pathogenic risk following land application.

Seeding effect on cocomposting wastewater biosolids with coal fly ash

The seeding effect on fly ash-amended biosolids composting was evaluated by inoculating a mixture of ash and biosolids with seeding materials before composting. These inocula included thermophilic bacteria (Bacillus. brevis, B. coagulans, and B. licheniformis) isolated from the ash-biosolids compost, a commercial decomposter, and recycled biosolids compost. Although the addition of these microbial additives to the ash-biosolids compost improved the population of thermophilic bacteria at the early stage of composting, the improvement was negligible after 4 days of composting. Inoculation with isolated bacterial culture, milk powder, or the decomposter, only, did not effectively improve the decomposition of organic matter compared with those receiving inoculation of both microbial additives and milk powder together. The isolated Bacillus species was as efficient as the commercial decomposter in accelerating the decomposition rate during ash-amended biosolids composting as indicated by the high amounts of carbon dioxide evolved and cumulative weight loss. Ash-biosolids compost inoculated with 15% (dry weight basis) of recycled compost showed a comparable decomposition activity to those inoculated with bacterial culture and the commercial decomposter with milk powder. Taking into consideration the lower operating cost and acceptable decomposition efficiency, recycled biosolids compost seemed to be a promising additive to ash-amended biosolids compost to improve composting efficiency.

Inhibitory effect of tetrabutylammonium ions on endothelium/nitric oxide-mediated vasorelaxation

Apart from the well-described K+ channel blocking effects in vascular smooth muscle cells, monovalent quaternary ammonium ions may also interact with endothelial cells in the endothelium-intact mammalian arteries. The present study was aimed to examine the effect of tetrabutylammonium ions on endothelium-dependent and -independent relaxation in the rat isolated aortic rings. Pretreatment with tetrabutylammonium concentration dependently reduced the endothelium-dependent relaxation induced by acetylcholine, cyclopiazonic acid and ionomycin. Tetrabutylammonium also inhibited endothelium-independent relaxation induced by hydroxylamine or nitroprusside. Pretreatment of endothelium-denuded rings with tetrabutylammonium did not affect relaxation induced by NS1619 or by diltiazem. In contrast, tetrabutylammonium significantly reduced the pinacidil- or cromakalim-induced relaxation. Tetrabutylammonium also inhibited the acetylcholine- but not nitroprusside-induced increase of tissue content of cyclic GMP in the aortic rings. The present study indicates that tetrabutylammonium ions could inhibit endothelial and exogenous nitric oxide-mediated aortic relaxation while it had no effect on relaxation induced by activation of Ca2+-activated K+ channels (by NS1619) or by inhibition of voltage-gated Ca2+ channels (by diltiazem). The inhibitory effect on pinacidil- and cromakalim-induced relaxation suggests that tetrabutylammonium ions also inhibit ATP-sensitive K+ channels in aortic smooth muscle cells.

Practical aspects of in situ 16O (gamma,n) 15O activation using a conventional medical accelerator for the purpose of perfusion imaging

We report investigations into the feasibility of generating radioactive oxygen (15O, a positron emitter, with half-life 2.05 min) using a tuned Elekta SL25 accelerator, for the end purpose of imaging tumor perfusion. 15O is produced by the "gamma, neutron," (gamma,n) reaction between high-energy photons and normal oxygen (16O) in the body. As most in vivo 16O is bound in water molecules the 15O radio-marker is produced in proportion to water content in tissue. Imaging the washout of the 15O distribution using sensitive positron-emission-tomography (PET) technology can yield spatial information about blood perfusion in the tissue. The aim of this article was to determine the amount of 15O activity that could be produced by the tuned medical accelerator. A further aim was to model the activation process using Monte Carlo and to investigate ways to optimize the amount of 15O that could be generated. Increased activation was achieved by (i) tuning the beam to give higher-energy electrons incident on the target of the accelerator, (ii) increasing dose rate by removing the conventional filtration in the beam and reducing the source to object distance, and (iii) reducing low-energy photons by means of a carbon block absorber. The activity per-unit-dose produced by the tuned beam was measured by irradiating spheres of water to known doses and placing the spheres in a calibrated coincidence-counting apparatus. Peak energy of the tuned bremsstrahlung beam was estimated at 29 MeV, and generated activity up to 0.24/microCi/cc/3Gy in water. The measured amount of 15O agreed to within 10% of the prediction from the Monte-Carlo-computed spectrum, indicating reasonable ability to model the activation process. The optimal thickness of the carbon absorber was found to be about 25 cm. The insertion of a carbon absorber improved spectral quality for activation purposes but at the cost of reduced dose rate. In conclusion, the viability of generating 15O with an Elekta SL25 has been demonstrated. In conjunction with recent advances in high-sensitivity portable PET imaging devices, real potential exists for imaging in situ activated 15O washout as a surrogate measurement of macroscopic tumor perfusion.

Ability of Agrogyron elongatum to accumulate the single metal of cadmium, copper, nickel and lead and root exudation of organic acids

Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0.05 and 0.5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92,754 mg/kg dry weight (DW) in roots and 11,683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for roots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30,261 mg/kg DW) at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12,230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni > Cu > Pb > Cd (mg/kg DW), and those in roots were Pb > Cd > Ni > Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing root exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb, a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no correlation between alternations in root exudation of organic acids and metal accumulation could be established.

Effect of dissolved organic matter from sludge and sludge compost on soil copper sorption

Interaction of Cu with dissolved organic matter (DOM) is an important physicochemical process affecting Cu mobility in soils. The aim of this study was to investigate the effects of DOM from anaerobically digested dewatered sludge and sludge compost on the sorption of Cu on an acidic sandy loam and a calcareous clay loam. In the presence of DOM, Cu sorption capacity decreased markedly for both soils, especially for the calcareous soil. The Cu sorption isotherms could be well described by the Freundlich equation (r2 = 0.99), and the binding intensity parameter of soils in the presence of sludge DOM was lower than compost DOM. An increase in DOM concentration significantly reduced the sorption of Cu by both soils. Within the Cu and DOM concentration range studied, the decrease in Cu sorption caused by sludge DOM was consistently greater than that of compost DOM. This might be attributed to the greater amount of hydrophobic fraction of DOM in the compost. Moreover, the reduction of Cu sorption caused by DOM was more obvious in the soil with higher pH. In addition, the sorption of Cu increased with an increase in pH for both soils without the addition of DOM, while Cu sorption in the presence of DOM was unexpectedly decreased with an increase in pH at a pH >6.8. This implied that DOM produced by sludge or other C-enriched organic wastes heavily applied on calcareous soils might facilitate the leaching loss of Cu because of the formation of soluble DOM-metal complexes.

Clinical use of electronic portal imaging: report of AAPM Radiation Therapy Committee Task Group 58

AAPM Task Group 58 was created to provide materials to help the medical physicist and colleagues succeed in the clinical implementation of electronic portal imaging devices (EPIDs) in radiation oncology. This complex technology has matured over the past decade and is capable of being integrated into routine practice. However, the difficulties encountered during the specification, installation, and implementation process can be overwhelming. TG58 was charged with providing sufficient information to allow the users to overcome these difficulties and put EPIDs into routine clinical practice. In answering the charge, this report provides; comprehensive information about the physics and technology of currently available EPID systems; a detailed discussion of the steps required for successful clinical implementation, based on accumulated experience; a review of software tools available and clinical use protocols to enhance EPID utilization; and specific quality assurance requirements for initial and continuing clinical use of the systems. Specific recommendations are summarized to assist the reader with successful implementation and continuing use of an EPID.

Thymocyte-targeted overexpression of xiap transgene disrupts T lymphoid apoptosis and maturation

The X-linked inhibitor of apoptosis (XIAP) and other members of the inhibitor of apoptosis (IAP) family can suppress apoptosis induced by a diverse variety of triggers. Functional studies done to date have focused on tissue culture models and adenovirus overexpression of XIAP and other IAP proteins. Here we report the phenotype of an engineered transgenic mouse overexpressing a human IAP, as well as assessing the long-term consequence of IAP overexpression. We document the relative protein expression levels of the endogenous mouse homologue to XIAP, mouse inhibitor of apoptosis (MIAP 3), within thymocyte and T cell subpopulations. The consequence of lymphoid-targeted overexpression of XIAP in transgenic mice suggests a physiological role for the endogenous protein, MIAP3. Xiap-transgenic mice accumulated thymocytes and/or T cells in primary and secondary lymphoid tissue, T cell maturation was perturbed, and transgenic thymocytes resisted a variety of apoptotic triggers both in vitro and in vivo. These observations imply a possible key function for the intrinsic cellular inhibitor XIAP in maintaining the homeostasis of the immune system.

Effects of composting process and fly ash amendment on phytotoxicity of sewage sludge

With the increasingly growing global production of sewage sludge, evaluation of its applicability in agriculture and land restoration is essential. This study assessed the potential effects of composting process and fly ash amendment on soil-ameliorating properties of sewage sludge. The metal availability and phytotoxicity of ash-amended sludge compost (AS, mature sewage sludge compost mixed with fresh lagoon ash) and sludge-ash co-compost (SA, co-composted mixture of sewage sludge and lagoon ash) were compared. The results of this work suggested that both composts favored the applicability of sewage sludge for land application by reducing Cd, Cu, Pb, and Zn availability. The SA co-compost stimulated seed germination at ash amendment rates of < or = 10%, whereas various treatments of AS compost inhibited germination at an extract dilution of 50%. Amendment of lagoon ash before or after sludge composting increased electrical conductivity (EC) and volatilization of NH4-N, but lowered availability of PO4-P. Together with the results of phytotoxicity, an optimal ash amendment rate of 5% for AS and 10% for SA were most desirable. Alkaline amendment prior to sludge composting was recommended, because it could be more effective in reducing soluble and plant-available metal concentrations through the composting process.

Improved high performance liquid chromatographic analysis of omeprazole in human plasma

A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.

Estimated coefficient of variation values for sample size planning in bioequivalence studies

OBJECTIVE

The aim of the present communication is to provide information regarding the intrasubject coefficent of variation obtained from 30 bioequivalence studies covering 16 drugs which can be used for estimation of sample size. Additionally, an attempt was also made to estimate the test power of each of the studies conducted.

METHODS

The intrasubject coefficient of variation was estimated from the residual mean square error obtained from analysis of variance of the parameters AUC0-infinity, Cmax and Cmax/AUC0-infinity after logarithmic transformation. The test power in the analyses of the above parameters was subsequently estimated using nomograms provided by Diletti et al. [1991].

RESULTS AND CONCLUSION

Thirty products covering 16 drugs were studied in which 22 were immediate-release (including one dispersible tablet) and 8 were sustained-release formulations. The intrasubject coefficient of variation for the parameter AUC0-infinity was smaller than Cmax, and hence considerably more studies were able to attain a power of greater than 80% using 12 volunteers for the AUC0-infinity, compared to the Cmax. However, the variability in the Cmax could be reduced by using the parameter Cmax/ AUC0-infinity, and thus, provide a more realistic estimation of sample size, since the latter reflects only the rate of absorption and not both the rate and extent as in the case of Cmax [Endrenyi et al. 1991].

Pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under different food status

We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.

Co-composting of soybean residues and leaves in Hong Kong

The goal of this project was to evaluate the feasibility of co-composting of soybean residues and leaves and the effects of turning frequency on compost quality. Soybean residues were mixed with leaves and sawdust in 1:1:3 (w/w wet weight) for achieving a C/N ratio of about 30. Three heaps of about 4 m3 of compost mixtures were prepared receiving a turning frequency of daily (pile A), 3-day (pile B) and weekly (pile C) turning. Different turning frequencies did not significantly affect the changes in pH and volatile solids throughout the composting period. High turning frequency caused a lower electrical conductivity and NH4-N contents as well as a shorter duration of thermophilic phase, because of a high heat loss by evaporation and volatilization of ammonia in the pile. The highest C decomposition of 4% occurred in the pile with a 3-day turning period, which coincided with the higher-nitrogen content in this treatment. All treatments with different turning frequencies reached maturation at 63 days as indicated by the soluble organic carbon, soluble NH4-N, C/N ratio and cress seed germination index. However, increasing the aeration during composting period was beneficial in accelerating the maturation process. Taking into consideration less labour and lower operation costs as compared to daily turning, it can be suggested that a 3-day turning frequency would be more appropriate for reaching acceptable quality of compost and ease in operation.

Modified arthroscopic suture fixation of displaced tibial eminence fractures using a suture loop transporter

Current arthroscopic suture fixation techniques of tibial eminence fractures are time consuming and the number of anchor sutures that can be placed is limited by the cumbersome and repetitive numerous needle threading steps. This occurs at 2 stages: first, when placing anchoring sutures through the avulsed anterior cruciate ligament stump with a suture punch, and second, when there is a need to traverse the tibial bone canal with the suture ends. We describe a modification that reduces the reliance on conventional rigid instruments and instead uses a loop transporter made from readily available suture material. The suture loop transporter being malleable reduces the necessary width of the tibial bone canal to be made and has a further advantage of minimizing the bone loss during the reaming of the bone tunnel. The subsequent potential for a stress fracture at these tunnel sites is also substantially reduced. Our technique is more user friendly, more accurate, and quicker to perform.

Fractionation and characterization of sludge bacterial extracellular polymers by FT-IR, 13C-NMR, 1H-NMR

Sludge bacterial extracellular (BEP) polymers exhibit a strong affinity with metals in addition to their role in the bioflocculation of activated sludge. It is of utmost importance in elucidating the chemical characterization of sludge BEP prior to a better understanding of its environmental behavior. Sludge BEP extracted from activated sludge was characterized by FT-IR, 1H-NMR, and 13C-NMR and fractionated into 6 fractions (hydrophilic acid, base, and neutral; and hydrophobic acid, base, and neutral). The results indicated that sludge BEP contained more polysaccharides but fewer amino acids or proteinaceous materials compared to dissolved organic matter (DOM) derived from sludge. No aromatic substance was found in sludge BEP as indicated by NMR. Sludge BEP was dominated by hydrophilic fractions, accounting for 65% of total DOC of sludge BEP and hydrophilic neutral constituted about 58% of the hydrophilic fraction. The chemical fraction and characterization indicated that sludge BEP might exhibit a higher capability in enhancing the transport of the associated contaminants through porous media than that of sludge DOM.

Monitor unit settings for intensity modulated beams delivered using a step-and-shoot approach

Two linear accelerators have been commissioned for delivering IMRT treatments using a step-and-shoot approach. To assess beam startup stability for 6 and 18 MV x-ray beams, dose delivered per monitor unit (MU), beam flatness, and beam symmetry were measured as a function of the total number of MU delivered at a clinical dose rate of 400 MU per minute. Relative to a 100 MU exposure, the dose delivered per MU by both linear accelerators was found to be within +/-2% for exposures larger than 4 MU. Beam flatness and symmetry also met accepted quality assurance standards for a minimum exposure of 4 MU. We have found that the performance of the two machines under study is well suited to the delivery of step-and-shoot IMRT. A system of dose calculation has also been commissioned for applying head scatter corrections to fields as small as 1x1 cm2. The accuracy and precision of the relative output calculations in water was validated for small fields and fields offset from the axis of collimator rotation. For both 6 and 18 MV x-ray beams, the dose per MU calculated in a water phantom agrees with measured data to within 1% on average, with a maximum deviation of 2.5%. The largest output factor discrepancies were seen when the actual radiation field size deviated from the set field size. The measured output in water can vary by as much 16% for 1x1 cm2 fields, when the measured field size deviates from the set field size by 2 mm. For a 1 mm deviation, this discrepancy was reduced to 8%. Steps should be taken to ensure collimator precision is tightly controlled when using such small fields. If this is not possible, very small fields should not contribute to a significant portion of the treatment, or uncertainties in the collimator position may effect the accuracy of the dose delivered.

Intensity modulation to improve dose uniformity with tangential breast radiotherapy: initial clinical experience

PURPOSE

We present a new technique to improve dose uniformity and potentially reduce acute toxicity with tangential whole-breast radiotherapy (RT) using intensity-modulated radiation therapy (IMRT). The technique of multiple static multileaf collimator (sMLC) segments was used to facilitate IMRT.

METHODS AND MATERIALS

Ten patients with early-stage breast cancer underwent treatment planning for whole-breast RT using a new method of IMRT. The three-dimensional (3D) dose distribution was first calculated for equally weighted, open tangential fields (i.e., no blocks, no wedges). Dose calculation was corrected for density effects with the pencil-beam superposition algorithm. Separate MLC segments were constructed to conform to the beam's-eye-view projections of the 3D isodose surfaces in 5% increments, ranging from the 120% to 100% isodose surface. Medial and lateral MLC segments that conformed to the lung tissue in the fields were added to reduce transmission. Using the beam-weight optimization utility of the 3D treatment planning system, the sMLC segment weights were then determined to deliver the most uniform dose to 100 reference points that were uniformly distributed throughout the breast. The accuracy of the dose calculation and resultant IMRT delivery was verified with film dosimetry performed on an anthropomorphic phantom. For each patient, the dosimetric uniformity within the breast tissue was evaluated for IMRT and two other treatment techniques. The first technique modeled conventional practice where wedges were derived manually without consideration of inhomogeneity effects (or density correction). A recalculation was performed with density correction to represent the actual dose delivered. In the second technique, the wedges were optimized using the same beam-weight optimization utility as the IMRT plan and included density correction. All dose calculations were based on the pencil-beam superposition algorithm.

RESULTS

For the sMLC technique, treatment planning required approximately 60 min. Treatment delivery (including patient setup) required approximately 8-10 min. Film dosimetry measurements performed on an anthropomorphic phantom generally agreed with calculations to within +/- 3%. Compared to the wedge techniques, IMRT with sMLC segments resulted in smaller "hot spots" and a lower maximum dose, while maintaining similar coverage of the treatment volume. A median of only 0.1% of the treatment volume received > or = 110% of the prescribed dose when using IMRT versus 10% with standard wedges. A total of 6-8 segments were required with the majority of the dose delivered via the open segments. The addition of the lung-block segments to IMRT was of significant benefit for patients with a greater proportion of lung parenchyma within the irradiated volume. Since August 1999, 32 patients have been treated in the clinic with the IMRT technique. No patient experienced RTOG grade III or greater acute skin toxicity.

CONCLUSION

The use of intensity modulation with an sMLC technique for tangential breast RT is an efficient and effective method for achieving uniform dose throughout the breast. It is dosimetrically superior to the treatment techniques that employ only wedges. Preliminary findings reveal minimal or no acute skin reactions for patients with various breast sizes.

Active breathing control (ABC) for Hodgkin's disease: reduction in normal tissue irradiation with deep inspiration and implications for treatment

PURPOSE

Active breathing control (ABC) temporarily immobilizes breathing. This may allow a reduction in treatment margins. This planning study assesses normal tissue irradiation and reproducibility using ABC for Hodgkin's disease.

METHODS AND MATERIALS

Five patients underwent CT scans using ABC obtained at the end of normal inspiration (NI), normal expiration (NE), and deep inspiration (DI). DI scans were repeated within the same session and 1-2 weeks later. To simulate mantle radiotherapy, a CTV1 was contoured encompassing the supraclavicular region, mediastinum, hila, and part of the heart. CTV2 was the same as CTV1 but included the whole heart. CTV3 encompassed the spleen and para-aortic lymph nodes. The planning target volume (PTV) was defined as CTV + 9 mm. PTVs were determined at NI, NE, and DI. A composite PTV (comp-PTV) based on the range of NI and NE PTVs was determined to represent the margin necessary for free breathing. Lung dose-mass histograms (DMH) for PTV1 and PTV2 and cardiac dose-volume histograms (DVH) for PTV3 were compared at the three different respiratory phases.

RESULTS

ABC was well-tolerated by all patients. DI breath-holds ranged from 34 to 45 s. DMHs determined for PTV1 revealed a median reduction in lung mass irradiated at DI of 12% (range, 9-24%; n = 5) compared with simulated free-breathing. PTV2 comparisons also showed a median reduction of 12% lung mass irradiated (range, 8-28%; n = 5). PTV3 analyses revealed the mean volume of heart irradiated decreased from 26% to 5% with deep inspiration (n = 5). Lung volume comparisons between intrasession and intersession DI studies revealed mean variations of 4%.

CONCLUSION

ABC is well tolerated and reproducible. Radiotherapy delivered at deep inspiration with ABC may decrease normal tissue irradiation in Hodgkin's disease patients.

Report of 2 fatal cases of adult necrotizing fasciitis and toxic shock syndrome caused by Streptococcus agalactiae

We describe 2 cases of fatal necrotizing fasciitis and toxic shock syndrome caused by Streptococcus agalactiae-a rare entity that has been reported in only 9 patients-in 2 nonpregnant adults.

Determinants of bioactivity of oxidized phospholipids. Specific oxidized fatty acyl groups at the sn-2 position

We previously described 3 bioactive oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC) containing oxovaleroyl (POVPC), glutaroyl (PGPC), and epoxyisoprostane (PEIPC) groups at the sn-2 position that were increased in minimally modified/oxidized low density lipoprotein (MM-LDL) and rabbit atherosclerotic lesions. We demonstrated specific and contrasting effects of POVPC and PGPC on leukocyte-endothelial interactions and described an effect of PEIPC on monocyte binding. The major purpose of the present study was to determine the effects of structural changes on the bioactivities of these 3 lipids. We demonstrate herein that the group at the sn-2 position determines the specific bioactivity and that the substitution of stearoyl for palmitoyl at the sn-1 position or ethanolamine for choline at the sn-3 position of the phospholipid did not alter bioactivity. Oxidized PAPC, oxidized 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine, and oxidized 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphorylethanolamine stimulated monocyte binding and inhibited lipopolysaccharide-induced expression of the neutrophil-binding molecule E-selectin. Furthermore, all oxovaleroyl phospholipids but not the glutaroyl phospholipids induced monocyte binding without an increase in vascular cell adhesion molecule-1 (VCAM-1) expression and inhibited lipopolysaccharide-induced E-selectin expression. In contrast, glutaroyl phospholipids but not oxovaleroyl phospholipids stimulated E-selectin and VCAM-1 expression. We further demonstrate that all parts of the phospholipid molecules are required for these bioactivities. Hydrolysis with phospholipase (PL) A(1), PLA(2), and PLC strongly reduced the bioactivities of POVPC, PGPC, and mixed isomers of PEIPC. PLD had a smaller but still significant effect. The effects of POVPC and PEIPC could be abolished by sodium borohydride treatment, indicating the importance of the reducible groups (carbonyl and epoxide) in these molecules. In summary, these studies identify 6 new bioactive, oxidized phospholipids that are increased in MM-LDL and, where measured, in atherosclerotic lesions. They thus suggest that a family of phospholipid oxidation products containing oxovaleroyl, glutaroyl, and epoxyisoprostane at the sn-2 position play an important role in the regulation of leukocyte-endothelial interactions, bioactivity being in part controlled by several types of phospholipid hydrolases.

Ultraviolet B-mediated phosphorylation of the small heat shock protein HSP27 in human keratinocytes

Exposure of human keratinocytes to environmental stress is known to induce changes in the expression, phosphorylation, and subcellular relocalization of the 27 kDa heat shock protein. This study demonstrates that ultraviolet B (280-320 nM) irradiation with physiologic doses induces a dose-dependent phosphorylation of 27 kDa heat shock protein, generating the more acidic 27 kDa heat shock protein B, C, and D isoforms. Ultraviolet B also induces perinuclear cytoplasmic relocation and nuclear translocation of 27 kDa heat shock protein and caused aggregation of cytoplasmic actin filaments into a broad perinuclear distribution. The ultraviolet B-induced phosphorylation is reversible, returning to baseline levels 4 h after exposure, and this coincides with the reversal of ultraviolet B-induced actin reorganization. The ultraviolet B-induced phosphorylation is not affected by the protein kinase C inhibitor, GF 109203X, is partially inhibited by epidermal growth factor receptor tyrosine kinase inhibitor, PD 153035, and is substantially inhibited by the specific p38 mitogen-activated protein kinase inhibitor, SB 203580. In addition, pretreatment of cells with the anti-oxidant N-acetyl cysteine partially inhibits ultraviolet B-and oxidant-induced 27 kDa heat shock protein phosphorylation. The p38 mitogen-activated protein kinase cascade is thus the major transduction pathway for ultraviolet B-induced 27 kDa heat shock protein phosphorylation, and reactive oxygen species generated in response to ultraviolet B also contribute to this phosphorylation. As 27 kDa heat shock protein phosphorylation and relocalization has been associated with increased cell survival after environmental insult, our data suggest that ultraviolet B, in addition to initiating recognized cytotoxic events in keratinocytes, also initiates a signaling pathway that may provide cellular protection against this ubiquitous environmental insult.

Photostimulated reactions of phenylacetic acid dianions with aryl halides. Influence of the metallic cation on the regiochemistry of arylation

[reaction: see text]Phenylacetic acid dianions react via what appears to be an S(RN)1 process with aryl halides under photostimulation to afford aryl substitution products 5 and 6. When the counterion is K+, only 4-biphenylacetic acids 5 are obtained. Both alpha- and para-coupling occurs with Na+ to give a mixture of 5 and 6, while exclusive formation of diphenylacetic acids 6 is observed with the dilithio salt of 1.

Compensation of x-ray beam penumbra in conformal radiotherapy

In radiotherapy, the gross tumor volume is surrounded by a clinically defined margin to allow for the presence of undetected malignant cells. Additional margins are added to accommodate positioning uncertainties and organ motion, creating a planning target volume, or PTV. Finally, a margin is included in the beam apertures surrounding the PTV to account for the dose fall-off at the beam edges (i.e., the "penumbra"). For higher energy beams and for low density tissues adjacent to the PTV, the beam aperture margin should be increased to account for the increased range of scattered photons and electrons. However, increased margins also increase the volume of normal tissue irradiated. In this work, the beam aperture margin is reduced by using filters and multileaf collimator (MLC) techniques to create compensating rinds of increased beam intensity. These compensation techniques were evaluated for 6 and 18 MV x rays by calculating penumbral widths as a function of the increased beam intensity in the rind, the rind width, and tissue density. Dose calculations were performed using a 3D superposition algorithm, which includes an extrafocal source model. Calculations were validated experimentally with film dosimetry. Results show the distance between the 95%-50% isodose lines is reduced from 11 mm to 4 mm for 6 MV x rays in the lung phantom, when the beam intensity is increased by 20% in a 10 mm wide rind. At 18 MV, this distance is reduced from 16 mm to 6 mm with a 20% increase in rind intensity, but a 15 mm wide rind is required. In all cases, penumbra compensation did not result in any appreciable increase in scatter dose outside the field boundaries. These results suggest that penumbra compensation is a practical means of controlling the beam aperture margin.