[A model analysis on the knowledge-attitude-practice of children guardians in Jiangxi, Shanghai and Qinghai]

Objective: To understand the knowledge attitude and practice (KAP) on vaccination among children's parents in Jiangxi, Shanghai, and Qinghai and explore the factors influencing KAP. Methods: The study selected two counties/districts in Jiangxi, Shanghai, and Qinghai, respectively, by stratified sampling and used a unified questionnaire to investigate the parental KAP of vaccination. A structural equation model (SEM) was used to explore factors influencing parental KAP, as well as the relationship between knowledge and behavior. Results: Of the 760 valid questionnaires, the knowledge of vaccination among children's parents was better, and the vaccination knowledge of parents in Qinghai and Shanghai were slightly better than those in Jiangxi. Parents mainly obtained vaccination knowledge through medical staff and vaccination manuals. The fitting degree of SEM was relatively good; the root mean square error of approximation of the model is 0.033. The higher the parents' education level, the better their knowledge of vaccination (β̂=0.082). Parental vaccination knowledge could influence whether the vaccinated children stay for half an hour in the clinics (β̂=0.541). It could also impact whether parents giving up vaccinating their children in the face of media reports about the adverse effects of vaccinations (β̂=0.515). Conclusions: The knowledge of vaccination among the parents in Jiangxi, Shanghai, and Qinghai was quite good. Moreover, we should pay more attention to the mass media programs and vaccination knowledge among parents with low or middle education backgrounds. Vaccination knowledge can be disseminated through medical staff, vaccination manuals, or mobile applications.

Energy conservation at an optical temporal boundary

The temporal boundary appears as a novel phenomenon in a wide range of optical devices and systems, such as the photonic crystal, metamaterials, optical microcavity, and modulator, with a dynamic medium whose refractive index changes across the boundary. However, the validation of electromagnetic energy conservation was considered in violation for the optical temporal boundary traditionally. Here a new energy space-time scheme is proposed for an optical pulse in a medium with the temporal boundary. From the Poynting theory, the electromagnetic energy is investigated based on a one-dimensional model under the assumption of impedance matching. Furthermore, the results demonstrate that a more general conservation of energy is validated in a time domain for the ideal scenario. A new invariant quantity of spatial energy in the optical medium is further obtained. The numerical results are in agreement with the theory of the temporal boundary. The conservative process of energy transportation across the optical temporal boundary is clarified and confirmed.

[A study on measles and rubella antibody level in 319 pairs of mothers and infants in Songjiang District of Shanghai]

Objective: To explore serum levels of measles and rubella IgG antibodies among mothers and infants. Methods: According to the inclusion and exclusion criteria, we selected 319 puerperae and their infants in maternal hospitals of Songjiang district November 2016 to February 2017, venous blood were collected and serum measles and rubella IgG antibodies were measured using ELISA. To study the correlation between the level of measles and rubella antibodies in infants and mothers' by using the Spearman's correlation analysis. Results: The age at delivery was (29.71±4.25) years old; and the gestational age at delivery was (39.06±1.30) weeks. The positive rate and protection rate of measles antibody in puerperae were 82.5% (243/319) and 43.3% (135/319), the GMC [M (QR)] was 655.74 (251.21-1 299.02) mIU/ml. The positive rate of rubella antibody in puerperae was 61.1% (195/319), the GMC [M (QR)] was 31.34 (11.65-73.61) IU/ml. The positive rate and protection rate of measles antibody in infants were 84.1% (270/321) and 46.1% (148/321), the GMC [M (QR)] was 665.07 (279.63-1 544.07) mIU/ml. The positive rate of rubella antibody in infants was 69.5% (223/321), the GMC [M (QR)] was 40.30 (16.12-98.48) IU/ml. There was statistical difference in measles (Z=-14.64, P<0.001) and rubella (Z=-8.66, P<0.001) antibody levels between mothers and infants. There was positive correlation in measles (r=0.76, P<0.001) and rubella (r=0.86, P<0.001) antibody level between mothers and infants. Conclusion: The maternal antibody of measles and rubella had a concentration effect. The level of measles and rubella antibodies in the infants was higher than that in the mothers' and increased with the increase of the level of measles and rubella antibodies in the mothers.

Anisotropic dependence of light extraction behavior on propagation path in AlGaN-based deep-ultraviolet light-emitting diodes

The anisotropic extraction dependence of polarized light on propagation path in AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) is investigated by simulations and photoluminescence (PL) measurements. Theoretical calculations based on k⋅p approximation and Monte Carol ray tracing indicate that there are two kinds of polarized sources with different angular distributions in ~280 nm AlGaN-based LEDs, s-polarized (spherical-shaped) and p-polarized (dumbbell-shaped) sources, which have different extraction behaviors. It is found that the total light extraction intensities are improved with decreasing the propagation path, and the lateral surface extraction gradually becomes dominant. Moreover, the extraction intensity of s-polarized light improves more than that of p-polarized light when the propagation path decreases, leading to a greater polarization degree. Polarization-resolved PL measurements show that the polarization degree of extracted light from lateral facet of the AlGaN multiple quantum well sample can be enhanced from 1% to 17% as the average propagation path reduces by 0.6 mm, which is consistent with the simulation results of the anisotropic dependence of light extraction on propagation path. Our results are significant for understanding and modulating the anisotropic extraction behavior of polarized light to realize high efficiency AlGaN-based DUV LEDs.

[The combined effects of family history of cardiovascular disease and overweight on ischemic stroke incidence among the Mongolian population]

Objective: To investigate the cumulative effect of family history of cardiovascular disease(CVD)and overweight on ischemic stroke events in the Mongolian population. Methods: Study participants were recruited from 32 villages from May 2002 to August 2012 in Kezuohou Banner(county)and Naiman Banner in Inner Mongolia, China. Among 3 457 Mongolian people aged ≥20 years old living in these villages, 2 589 were selected to participate in this study. None of the participants had chronic kidney disease, malignant tumor, thyroid disease or adrenalopathy, or acute infectious disease. The 2 589 participants were followed for a mean of 9.2 years. Six participants were lost to follow up, resulting in a follow-up rate of 99.8%. Information collected included demographic characteristics, lifestyle risk factors, alcohol consumption, cigarette smoking, history of disease, family history of CVD, and physical examination. Ischemic stroke incidence information was collected during follow-up. All participants were categorized into four subgroups according to family history of CVD and overweight status. Cox proportional hazards models were used to estimate the hazard ratios(HR)and 95% CI of ischemic stroke events among subgroups, compared with the subgroup with no family history of CVD and body mass index(BMI)<24 kg/m²(the reference group). Results: Among 2 589 participants, 76 ischemic stroke events occurred after follow-up, and 8 were excluded because of lack of key data. Finally, 2 581 participants were included in the analysis, and the incidence density was 323/100 000 person-years. The cumulative incidence rates of ischemic stroke were 2.48%, 1.86%, 6.67% and 9.00% in the no family history of CVD and BMI <24 kg/m², no family history of CVD and BMI ≥24 kg/m², family history of CVD and BMI <24 kg/m² and family history of CVD and BMI ≥ 24 kg/m² subgroups, respectively. Using the Cox proportional hazards model, after further adjustment for age, gender, smoking, drinking, FPG, hypertension, total cholesterol, triglycerides, and heart rate, the risk of ischemic stroke in the subgroup with a family history of CVD and BMI ≥24 kg/m² was higher than the reference group(HR: 2.61, 95% CI: 1.16-5.87). However, the risk of ischemic stroke in other two groups was not statistically significant compared with the reference group. The HR(95% CI)values in the no family history of CVD and BMI ≥24 kg/m²and family history of CVD and BMI <24 kg/m² subgroups were 1.18(0.5- 2.39)and 1.27(0.67- 2.42), respectively. Conclusion: In the Mongolian population, a family history of CVD and coexistent overweight may increase the risk of ischemic stroke events, suggesting that in people with family history of cardiovascular disease, weight control is conducive to the prevention of ischemic stroke.

Clinical commissioning of an in vivo range verification system for prostate cancer treatment with anterior and anterior oblique proton beams

The purpose of this work is the clinical commissioning of a recently developed in vivo range verification system (IRVS) for treatment of prostate cancer by anterior and anterior oblique proton beams. The IRVS is designed to perform a complete workflow for pre-treatment range verification and adjustment. It contains specifically designed dosimetry and electronic hardware and a specific software for workflow control with database connection to the treatment and imaging systems. An essential part of the IRVS system is an array of Si-diode detectors, designed to be mounted to the endorectal water balloon routinely used for prostate immobilization. The diodes can measure dose rate as function of time from which the water equivalent path length (WEPL) and the dose received are extracted. The former is used for pre-treatment beam range verification and correction, if necessary, while the latter is to monitor the dose delivered to patient rectum during the treatment and serves as an additional verification. The entire IRVS workflow was tested for anterior and 30 degree inclined proton beam in both solid water and anthropomorphic pelvic phantoms, with the measured WEPL and rectal doses compared to the treatment plan. Gafchromic films were also used for measurement of the rectal dose and compared to IRVS results. The WEPL measurement accuracy was in the order of 1 mm and after beam range correction, the dose received by the rectal wall were 1.6% and 0.4% from treatment planning, respectively, for the anterior and anterior oblique field. We believe the implementation of IRVS would make the treatment of prostate with anterior proton beams more accurate and reliable.

Water equivalent path length measurement in proton radiotherapy using time resolved diode dosimetry

PURPOSE

To verify water equivalent path length (WEPL) before treatment in proton radiotherapy using time resolved in vivo diode dosimetry.

METHODS

Using a passively scattered range modulated proton beam, the output of a diode driving a fast current-to-voltage amplifier is recorded at a number of depths in a water tank. At each depth, a burst of overlapping single proton pulses is observed. The rms duration of the burst is computed and the resulting data set is fitted with a cubic polynomial.

RESULTS

When the diode is subsequently set to an arbitrary depth and the polynomial is used as a calibration curve, the "unknown" depth is determined within 0.3 mm rms.

CONCLUSIONS

A diode or a diode array, placed (for instance) in the rectum in conjunction with a rectal balloon, can potentially determine the WEPL at that point, just prior to treatment, with submillimeter accuracy, allowing the beam energy to be adjusted. The associated unwanted dose is about 0.2% of a typical single fraction treatment dose.

Design of shared instruments to utilize simulated gravities generated by a large-gradient, high-field superconducting magnet

A high-field superconducting magnet can provide both high-magnetic fields and large-field gradients, which can be used as a special environment for research or practical applications in materials processing, life science studies, physical and chemical reactions, etc. To make full use of a superconducting magnet, shared instruments (the operating platform, sample holders, temperature controller, and observation system) must be prepared as prerequisites. This paper introduces the design of a set of sample holders and a temperature controller in detail with an emphasis on validating the performance of the force and temperature sensors in the high-magnetic field.

Commissioning a passive-scattering proton therapy nozzle for accurate SOBP delivery

Proton radiotherapy centers that currently use passively scattered proton beams do field specific calibrations for a non-negligible fraction of treatment fields, which is time and resource consuming. Our improved understanding of the passive scattering mode of the IBA universal nozzle, especially of the current modulation function, allowed us to re-commission our treatment control system for accurate delivery of SOBPs of any range and modulation, and to predict the output for each of these fields. We moved away from individual field calibrations to a state where continued quality assurance of SOBP field delivery is ensured by limited system-wide measurements that only require one hour per week. This manuscript reports on a protocol for generation of desired SOBPs and prediction of dose output.

Reply to comment on 'Modelling of surface energies of elemental crystals'

In reply to the comment by Luo et al, our theoretical model for the surface energy of elemental crystals is further developed to improve the prediction accuracy of the surface energy of the high-Miller-index facets. It is considered that the previous predicted unit surface area could not denote the actual one since the facets now are uneven. With the modification, the accuracy for the prediction of surface energy in units of J m(-2) is improved.

Anti-CD25 mAb, anti-IL2 mAb, and IL2 block tolerance induction through anti-CD154 mAb and rapamycin in xenogeneic islet transplantation

BACKGROUND

We have used anti-CD154 monoclonal antibody (mAb; MR1) and rapamycin (rapa) to induce tolerance to islet xenografts. The aim of this study was to investigate whether classical anergy and/or regulation by interleukin (IL)2-dependent CD25+ T regulatory cells played roles in the induction and maintenance of tolerance in this model.

METHODS

Streptozotocin-induced diabetic mice were transplanted with rat islets. We performed the following groups: control group, islet transplantation without therapy; rapamycin group, 0.2 mg/kg by oral gavage on days 0, 1, 2, and every other day to day 14; anti-CD154 mAb (MR1) group, 0.5 mg intraperitoneally on days 0, 2, and 4; combination therapy group with rapa and MR1. We then administered in addition to the combination therapy with early (from days 0 to 14 [for IL2] or to 28 [for anti-IL2 mAb and anti-CD25 mAb] post-transplantation) or late (from days 100 to 114 [for IL2] or to 128 [for anti-IL2 mAb and anti-CD25 mAb] posttransplantation) recombinant IL2 (2000 U, intraperitoneally twice a day), a neutralizing anti-IL2 mAb (S4B6-1, 0.3 mg intraperitoneally twice weekly), and a depleting anti-CD25 mAb (PC61, 0.3 mg intraperitoneally twice weekly), respectively. Histology was performed at time of rejection.

RESULTS

Rapa and MR1 therapy alone significantly prolonged xenograft survival compared to the control group: median graft survival was 34 days versus 17 days (P<.05) and 98 days versus 17 days (P<.05), respectively, but rejection still occurred. Combination therapy with MR1 and rapa allowed indefinite graft survival (median graft survival [MGS]>200 days, P<.001). When exogenous IL2 was administered early with MR1 and rapa, rapid rejection developed in 18 of 18 mice (MGS 7 days), whereas when IL2 was given late, only 3 of 10 developed rejection. Early administration of anti-IL2 mAb led to rejection in 10 of 10 mice (MGS 42 days), whereas late administration led to rejection in only one of four mice. Early administration of anti-CD25 mAb led to rejection in eight of nine mice (MGS 49 days), whereas late administration led to rejection in only three of seven mice.

CONCLUSIONS

Rapa and MR1 allowed indefinite graft survival of islet xenografts. Classical anergy and regulation by IL2-dependent CD25+ T regulatory cells were critical in the induction of tolerance in the immediate posttransplantation period and less important for maintenance of tolerance.

Fine-tuning the synthesis of ZnO nanostructures by an alcohol thermal process

A simple and efficient alcohol thermal technique was applied to control the growth of the dimensions and morphology of ZnO nanostructures under mild conditions, where surfactant was not necessary. The size of ZnO nanocrystals increased with growth temperature and they transformed into nanorods with different aspect ratios through tuning the reaction time. The length of nanorods increased significantly with the reaction time, but their thickness only slightly increased. The as-prepared ZnO nanocrystals were monocrystalline and the growth orientation of ZnO nanorods was [001]. Photoluminescence measurements showed a blue shift in violet emission with a reduction in crystal size and revealed the quantum confinement effect. Electron irradiation induced structural damage was observed in the ZnO nanorods synthesized at 120 degrees C. Experimental results proved that the possible growth mechanism of ZnO nanostructures was oriented attachment.

Identification and quality assessment of Houttuynia cordata injection using GC-MS fingerprint: a standardization approach

Houttuynia cordata (Saururaceae) injection (HCI) was widely used to treat disease in China. At present, there were about 40 factories producing HCI, but a good quality standard for its quality control was lacking. In this study, an optimized and validated gas chromatography-mass spectrum (GC-MS) method was applied for the fingerprint analysis of 340 batches of HCI from 34 Chinese pharmaceutical factories. The results showed that HCI from the same factory had very similar GC-MS fingerprints, and evident difference existed among different factories. The representative fingerprints from 20 factories whose intra-factory correlation coefficients were over 0.90 and inter-factory correlation coefficients were over 0.75 were used to calculate the mean fingerprint of all samples. Spectral correlative chromatogram (SCC) was adopted to identify common component in different samples. Fifteen main "common components" were obtained. The mean fingerprint containing those 15 components was suggested to be used as characteristic fingerprint for the rapid identification of HCI and evaluation of the consistency of HCI from factory to factory and from batch to batch.

Anti-inflammatory effect of Houttuynia cordata injection

Houttuynia cordata (Saururaceae) injection (HCI) is a traditional Chinese medicine used in China. It was chosen as one of eight types of traditional Chinese medicine that play a unique role in severe acute respiratory syndrome (SARS) owing to the effect of curbing inflammation. In order to validate this plausible anti-inflammatory property, the chemical composition of HCI has been analysed by GC/MS, 22 components were identified, and the inflammation induced by carrageenan in the rat pleurisy model and by xylene in the mice ear edema model was adopted to study the anti-inflammatory activity of HCI. Injection of carrageenan into the pleural cavity elicited an acute inflammatory response characterized by protein rich fluid accumulation and leukocyte infiltration in the pleural cavity. The peak inflammatory response was obtained at 24 h when the fluid volume, protein concentration, C-reactive protein and cell infiltration were maximums. The results showed that these parameters were attenuated by HCI at any dose and touched bottom at dose of 0.54 ml/100 g, although less strong than dexamethasone. This drug was also effective in inhibiting xylene induced ear edema, and the percentage of inhibition came to 50% at dose of 80 microl/20 g. The results clearly indicate that HCI have anti-inflammatory activity.

Surface Tension and Its Temperature Coefficient for Liquid Metals

Temperature-dependent surface tension gamma(lv)(T) and its temperature coefficient (T) [=dgamma(lv)(T)/dT] for liquid metals are thermodynamically determined on the basis of an established model for surface energy of crystals. The model predictions correspond to the available experimental or theoretical results. It is found that for metallic liquids gamma(lv)(T(m)) proportional, variant H(v)/V(m)(2/3), gamma(lv)(T) proportional, variant T, and (T) proportional, variant T over a certain temperature range (including T < T(m) and T >/= T(m)), where H(v) and V(m) are the liquid-vapor transition enthalpy at boiling temperature T(b) and the atomic volume at melting temperature T(m), respectively. Furthermore, T(m)(T(m))/gamma(lv)(T(m)) almost remains constant, which gives a way to estimates of (T(m)) values when T(m) and gamma(lv)(T(m)) are known.

Clinical efficacy and mechanism of oxaliplatin in treating human gastric carcinoma

AIM

To evaluate the therapeutic effect of oxaliplatin on human gastric carcinoma and to explore the mechanisms.

METHODS

22 cases of stage IV gastric carcinoma patients received 4-6 (mean 4.6) cycles of first line combined chemotherapy with oxaliplatin (oxaliplatin 85 mg/m², ivgtt, 1 h, d 1; leukovorin 200 mg/m², iv, gtt, 1 h, d 1-5; 5-FU 300 mg/m², iv, d 1-2; 5-FU, continuously iv, gtt, 48 h; 1 cycle/2w). Response rate, progression-free survival (PFS), total survival time, toxic side effects were evaluated. The inhibitory effect of oxaliplatin on human gastric cell line SGC-7901 was calculated by MTT and IC50 was measured. Flow cytometry and TUNEL were applied to evaluate the apoptosis of cell line induced by the drug. The expression of caspase-3 mRNA was detected by RT-PCR.

RESULTS

Total response (complete and partial) occurred in 9 (40.9%) patients. Mean PFS was 4.2 months and mean total survival time was 7.2 months. Cumulative neurotoxicity (all grade I-II), vomiting and diarrhea, myelosuppression appeared in 93.5%, 20%, 32.9% of the patients, respectively. Apoptosis index was elevated after incubating with 1 mmol/L oxaliplatin for 30 min, but without statistic significance (P>0.05), but was much higher both by flowcytometry and TUNEL with statistical significance (P<0.05) after incubating with 1 mmol/L oxaliplatin for 2 days. Caspase-3 mRNA expression was elevated in oxaliplatin treated cells and correlated with apoptosis induced by the drug.

CONCLUSION

Oxaliplatin is effective and well-tolerated on human advanced gastric carcinoma. Oxaliplatin could significantly inhibit the growth of human gastric cell line SGC-7901, inducing caspase-3 mRNA expression and cell apoptosis.

Comparative biokinetics of tritium in rats during continuous ingestion of tritiated water and tritium-labeled food

PURPOSE

The biokinetics of tritium during continuous ingestion of tritiated water and tritiated wheat were investigated to estimate the radiation dose rates at the end of two modes of chronic exposure.

MATERIALS AND METHODS

Wistar strain male rats continuously ingested tritiated water as drinking water and tritiated wheat as food for 14 weeks. Urine and tissue samples were obtained and total tritium in the fresh wet samples and organically bound tritium (OBT) in the freeze-dried samples were determined.

RESULTS

The biokinetics of tritium was different between the two modes of exposure. The concentration of total tritium in the tissues exposed to tritiated water attained a steady-state condition by 2-3 weeks. The steady-state condition in the case of exposure to tritiated wheat was not observed for 10 weeks after the start of exposure in the majority of tissues. The relatively efficient and prolonged OBT formation during chronic exposure to tritiated wheat resulted in relatively high incorporation and retention of tritium in the tissues compared with those for exposure to the same activity of tritiated water.

CONCLUSION

Radiation dose rates estimated at the end of continuous ingestion showed that tritiated wheat gave higher dose rates than tritiated water by a factor of 1.3 to 4.5, but the factors were within 2.0 in the majority of tissues except for small intestine and adipose tissue.

Expression changes of activin A in the development of hepatic fibrosis

AIM: To examine the expression of activin A, a member of the transforming growth factor (TGF-β) superfamily, recently has been reported to beoverexpressed in liver cirrhosis, in the course of carbon tetrachloride-induced rat hepatic fibrosis.

METHODS: Hepatic fibrosis was induced in rats by subcutaneous injections of 40% carbon tetrachloride oily solution for a period of 1 to 7 weeks. At the end of 1, 2, 3, 4, 5, 6 and 7 weeks after carbon tetrachloride injections, the rats were killed in group (6-10 rats each time) for study. The activin A messenger RNA expression and its protein localization were assessed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTS: The normal rat liver expressed activin A mRNA and protein, and its expression was transiently decreased and became undetectable after carbon tetrachloride injections for 2 or 3 weeks and then increased gradually. After injection of carbon tetrachloride for 6 and 7 weeks, activin A mRNA and protein expressions were significantly enchanced in rat liver. Compared with that of the normal rat liver. Activin A mRNA expression levels in rats receiving carbon tetrachloride injections for 6 and 7 weeks were 1.6 and 2.2 times that of those in normal rat liver respectively (0.456 ± 0.094 vs 0.286 ± 0.0670, P < 0.01; 0.620 ± 0.134 vs 0.286 ± 0.0670, P < 0.01). Immunohistochemistry showed that activin A expressed in hepatocytes of normal liver, and its expression was decreased in rats receiving carbon tetrachloride for 2 or 3 weeks. Compared with normal liver, activin A expression distribution mode changed in fibrotic liver, being increased significantly in hepatocytes around fibrotic areas.

CONCLUSION: Activin A expression was increased in late stage of hepatic fibrosis, and this may be involved in hepatic fibrosis formation in this period.

Reduction of cardiac volume in left-breast treatment fields by respiratory maneuvers: a CT study

PURPOSE

A previous study of healthy female volunteers suggested that deep inspiratory breath holding can reduce the cardiac volume in the treatment portals for left-breast cancer treatment. The reduction of irradiated cardiac volume may be important considering the reported late cardiac morbidity and mortality and the frequent coexistent use of potentially cardiotoxic chemotherapy in breast cancer patients. In the present study, we evaluated the heart volume in the fields and, thus, the true benefit of this respiratory maneuver in breast cancer patients undergoing CT simulation.

MATERIALS AND METHODS

Fifteen patients (median age, 53) were studied. For each patient, CT scans were performed both when the patient breathed normally (quiet respiration) and when the patient held her breath after a deep inspiration. Tangential fields were planned using the same medial, lateral, superior, and inferior borders on skin for the normal breathing and the breath-holding configurations. The cardiac and left-lung volumes within the tangential fields were calculated for both breathing configurations. Multiple scan series were performed for the breath-holding configuration to provide a more accurate delineation of the cardiac tissue and to study the reproducibility of the patient's position between different cycles of deep inspiration.

RESULTS

None of the patients had difficulty holding her breath for 20 s. The cardiac volume in the field was reduced (-86 +/- 24%; p < 0.001) when patients held their breath after a deep inspiration compared to when breathing normally. For 7 patients (47%), deep inspiration moved the heart completely out of the radiation fields. The expansion of the lung tissue due to deep inspiration also increased the absolute lung volume in the tangential fields (183 cm(3) vs 97 cm(3), p < 0.001). However, the fractional volume of the left lung in the field was essentially unchanged. For all but 1 patient, the maximum difference between the external body contours from different breath holding cycles was 5 mm and occurred at the lateral aspect of the breast. At the medial aspect, as indicated by the position of the midline marker, the variations were well within the currently accepted tolerance for patient positioning during tangential treatment.

CONCLUSIONS

Deep-inspiration breath holding substantially reduces cardiac volume in the tangential fields for left-sided breast cancer treatment. The variation between patient positions at different cycles of breath holding was found to be reasonably small. Therefore, it appears feasible to reduce cardiac radiation by treating patients with intratreatment minifractions lasting 10-15 s while patients hold their breath.

Effects of alcohols on lipid bilayers with and without cholesterol: the dipalmitoylphosphatidylcholine system

Differential scanning calorimetry is a useful method to study the thermotropic phase transitions of a phospholipid bilayer. In the present study DSC is used to determine the effects of methanol and ethanol on DPPC and DPPC/2 mol% cholesterol bilayers. The biphasic effect of the main transition and the presence of an extra peak on the DSC cooling scans were observed above certain alcohol concentrations. In the presence of 2% cholesterol, the concentration at which the biphasic effect occurs is increased by both short-chain alcohols. 1,6-Diphenyl-1,3,5-hexatriene (DPH) is used as a fluorescent probe to directly determine the onset of interdigitation in these systems as reflected by a drop in the DPH fluorescence intensity.

Virtual light field projection for CT-simulation

We report a method to project a virtual light field over the patient during CT-simulations of external beam radiotherapy. It can be used to perform all the tasks associated with the physical light field of a conventional simulator. The system consists of a three-dimensional sonic digitizer interfacing with a window-based software on a personal computer. The digitizer can provide the three-dimensional coordinates of any point in space accessible by the digitizer probe. When these coordinates are transformed into the beam's eye view, the position of the digitized point relative to the beam can readily be displayed. Thus, the system establishes a virtual light field in space, which can be "seen" only by the digitizer probe. For any digitized point, the system can immediately show, by the beam's eye view display, whether the point is inside the field, outside of the field, or on the field border. Moreover, this virtual field projection allows one to evaluate external target coverage (or external normal tissue sparing) conveniently and interactively. By simply digitizing the concerned area and viewing its position in the beam's eye view display, one can immediately assess the coverage and if necessary, modify the treatment field accordingly. The system also provides an efficient and essential procedure in CT-simulations for marking treatment portals on the patient. By cruising the digitizer probe on the patient's skin surface under visual and audio guidances, one can promptly find the projection of the field center, field corners, etc., on the patient. Measurements have been performed to study the accuracy of the GP-12 sonic digitizer using rigid phantoms. Based on the measured data, the overall accuracy of the portal localization system is estimated to be +/-2 mm. The system has been in clinical use for our CT simulator.

Circadian and septadian variation in the occurrence of acute myocardial infarction in a Chinese population

To investigate whether circadian or any other temporal pattern(s) exist in the occurrence of acute myocardial infarction (AMI) in a Chinese population, we analyzed 428 patients with confirmed AMI for temporal patterns of AMI occurrence. The patients admitted to the Affiliated Hospital of Shandong Medical University during 1991-95 were from Jinan, the capital city of Shandong Province of China, which has a population of 2.5 million. The chi-square test for goodness of fit was used to test the difference among the frequencies of AMI occurrence in 4 equal intervals (01.00-07.00 h, 07.00-13.00 h, 13.00-19.00 h, 19.00-01.00 h) during the day and among those on 7 days during the week. The results showed that AMI occurrence exhibited significant circadian (p<0.001) and septadian (day of the week) (p=0.046) periodicity, with a peak at 01.00-07.00 h and a trough at 13.00-19.00 h during the day, and a peak on Saturday and a trough on Wednesday during the week. The peak to trough ratio of risk was 2.7 during the day and 2.1 during the week. It is concluded that there were circadian and septadian biorhythms in AMI occurrence in the Chinese population and that these were different from those observed in Western populations. Further investigation of the underlying mechanisms may shed further light on the trigger mechanisms of AMI and thus be helpful in the prevention and treatment of AMI.

Optimized beam planning for linear accelerator-based stereotactic radiosurgery

PURPOSE

Current treatment planning for linear accelerator-based stereotactic radiosurgery and radiotherapy is a lengthy and iterative procedure. The planner has to manually select the beam arcs and carefully consider many different selections to ensure target volume coverage while sparing dose to critical organs. In this article we report an optimization procedure that can automatically select the beam arcs based on geometric and dosimetric analysis of the treatment parameters.

METHODS AND MATERIALS

The optimization problem is introduced by using a Beam's Eye View (BEV) map where a pattern of lines represents a beam arc combination for a treatment plan. The collection of all possible treatment plans is described by using the concept of phase space where each point corresponds to a particular configuration of the system under consideration, and in this case, a particular beam arc combination. A geometric reduction of the phase space is performed by excluding static beam ports that irradiate too much critical organs and too little target volume. The phase space is further reduced by excluding beam arc combinations that do not comply with treatment convenience considerations and established planning experiences. These reductions significantly reduces the number of beam arc combinations to be considered and thus dramatically simplifies the computational complexity. The method of simulated annealing is then used to the reduced phase space to select the set of beam arcs that provides the best surface dose distribution for the target volume. The optimization procedure is applied to a radiosurgery case to compare the optimized beam arcs with the previously manually planned beam arcs. The procedure is also applied to 10 randomly selected cases for a comparison in terms of tissue-volume ratio calculations.

RESULTS

The system is a highly automated beam arc planning tool for stereotactic radiosurgery and stereotactic radiotherapy. Its interactive nature allows the planner to rapidly consider many treatment plans to search for the best option. For the case presented, it is shown that the optimized beams substantially reduce the dose to the postrema. The tissue-volume ratio calculations demonstrate that the optimization often produces clinically superior treatment plans than the manual beam planning method.

CONCLUSIONS

Our method of phase space reduction proves to be very useful in approaching the complex problem of treatment planning optimization. Not only does it substantially reduce the number of beam arcs that need to be considered, but it also simplifies the evaluation of the beam arc options. Both of these greatly reduce the computational complexity of the optimization and make the procedure fast and efficient. Moreover, the reduction of phase space adds another layer of interaction between the user and the beam selection procedure, so that the optimization process is well controlled and thus very effective.

Interactions of the components of the general secretion pathway: role of Pseudomonas aeruginosa type IV pilin subunits in complex formation and extracellular protein secretion

The general secretion pathway (GSP), found in a wide range of bacteria, is responsible for extracellular targeting of a subset of proteins from the periplasm. In Pseudomonas aeruginosa, the GSP requires the participation of 12 proteins, of which XcpT, XcpU, XcpV, XcpW are homologues of PilA, the major subunit of type IV pili. The interaction between the pilin-like Xcp proteins was investigated using bifunctional crosslinking reagents. Cross-linking analysis of whole cells of wild-type P. aeruginosa, followed by immunoblot analysis, revealed a 34-kDa XcpT-containing complex. This complex was shown to consist of XcpT/PilA heterodimers. The role of PilA in the GSP was examined, using P. aeruginosa mutants in the pilA gene, or in rpoN, a gene regulating pilA expression. Each mutant showed a significant reduction in the efficiency of extracellular protein secretion, and this defect could be restored by expression of the cloned pilA gene in the mutant cells. The formation of the PilA/XcpT complex did not require XcpR or XcpQ, two other components of the secretion machinery, nor did it require the pilus biogenesis factors PilB and PIlC. The dimeric XcpT/PilA complex was also formed in a pilD mutant, which lacks the leader peptidase enzyme, demonstrating that the leader peptide at the N-terminus or PilA or XcpT did not have to be removed for the dimerization to occur. XcpW and XcpU can also be crosslinked to form dimeric complexes with PilA. When expression of XcpT is increased, its homodimers, as well as XcpT/XcpW heterodimers, can be detected. Finally, an oligohistidine-tagged XcpT was shown to form stoichiometric complexes with PilA, and with XcpT, U, V and W. These dimers were co-purified by nickel-affinity chromatography. The results of this study suggest that XcpT can form heterodimers with PilA, and Xcp U, V and W, which may be assembly intermediates of the secretion apparatus. Alternatively, these may represent dynamic intermediates that facilitate protein secretion by continuous association and dissociation. The requirement for PilA for efficient protein secretion argues for a critical role played by PilA in two related processes during P. aeruginosa infections: formation of an adhesive pilus organelle and secretion of exoenzymes.

Clinical evaluation of a rapid immunochromatographic assay based on the 38 kDa antigen of Mycobacterium tuberculosis on patients with pulmonary tuberculosis in China

SETTING

A rapid membrane-based antibody assay capable of diagnosing pulmonary tuberculosis within 15 min has been developed using the 38 kDa antigen from Mycobacterium tuberculosis.

OBJECTIVE

To determine the specificity and sensitivity of this assay and evaluate its usefulness in a clinical setting.

DESIGN

Sera from patients with active pulmonary tuberculosis were obtained from three hospitals in China. The control groups consisted of patients who were diagnosed with lung diseases other than tuberculosis and healthy subjects.

RESULTS

Antibody was detected in 54 of 61 (89%) sputum positive patients and 67 of 91 (74%) sputum negative patients who had been clinically diagnosed as having active pulmonary tuberculosis. Five out of 56 (9%) patients with respiratory diseases other than tuberculosis and 1 out of 30 (3%) healthy controls had a positive antibody response. The overall specificity of the assay was 93% and the positive predictive value was 95%. We conclude that this assay is rapid, sensitive and specific and will be a valuable aid in the clinical diagnosis of pulmonary tuberculosis.

A specific targeting domain in mature exotoxin A is required for its extracellular secretion from Pseudomonas aeruginosa

A number of Gram-negative bacteria, including Pseudomonas aeruginosa, actively secrete a subset of periplasmic proteins into their surrounding medium. The presence of a putative extracellular targeting signal within one such protein, exotoxin A, was investigated. A series of exotoxin A truncates, fused to beta-lactamase, was constructed. Hybrid proteins, which carry at their N- termini 120, 255, 355 or the entire 613 residues of the mature exotoxin A, were stable and were secreted into the extracellular medium. Hybrid proteins which carry residues 1-30 and 1-60 of the mature exotoxin A were unstable; however, they could be detected entirely within the cells after a short labeling period. A hybrid with beta-lactamase was constructed which carried only the N-terminal residues 1-3 and region 60-120 of exotoxin A. It was also secreted into the culture medium, suggesting that a specific 60 amino acid domain contains the necessary targeting information for translocation of exotoxin A across the outer membrane. The secretion of the hybrid proteins is independent of the passenger protein, since a similar exotoxin A-murine interleukin 4 hybrid protein was also secreted. The extracellular targeting signal between amino acids 60 and 120 is rich in anti-parallel beta-sheets. It has been shown previously to be involved in the interaction of the exotoxin A with the receptors of the eukaryotic cells. In the three- dimensional view, the targeting region is on the toxin surface where it is easily accessible to the components of the extracellular secretion machinery.

Effects of egtazic acid and calcimycin on synthesis of DNA and collagen in cultured human lung fibroblasts

AIM

To study the effects of egtazic acid (EA) and calcimycin (Cal) on the synthesis of DNA and collagen in cultured human lung fibroblasts (HLF).

METHODS

The synthesis of DNA and collagen was determined by measuring the incorporation of [3H]TdR and [3H]proline of HLF respectively.

RESULTS

The collagen synthesis increased markedly 24 h after exposure to both EA (0.05-4 mmol.L-1) and Cal (0.25-20 mumol.L-1), and that there was no obvious change in DNA synthesis. After 36-48-h exposure, both DNA and collagen syntheses decreased in the groups of EA (1, 2, and 4 mmol.L-1); the DNA synthesis was also suppressed in Cal groups in a concentration-dependent manner, whereas collagen synthesis decreased only in Cal (10 and 20 mumol.L-1).

CONCLUSION

Extracellular Ca2+ influx into fibroblasts increased collagen production, However, the DNA synthesis was suppressed when the cytosolic Ca2+ was too high or too low.

Effects of tetrandrine and chlorpromazine on synthesis of collagen and hyaluronic acid in cultured human lung fibroblasts

AIM

To study the effects of tetrandrine (Tet) and chlorpromazine (Chl) on synthesis of collagen and hyaluronic acid (HA) in cultured human lung fibroblasts (HLF).

METHODS

The synthesis of collagen and HA was assessed by measuring the incorporation of [3H]proline and radioimmunoassay.

RESULTS

Both Tet (5-80 mumol L-1) and Chl (10-40 mumol L-1) diminished the collagen synthesis in a concentration-dependent manner. The suppression was aggravated at 36-48 h. The HA content in the supernatant of culture also decreased gradually with the increasing dosage of Tet or Chl after 24-h exposure. There was no obvious toxic effect of Tet on HLF cells at 5-20 mumol L-1.

CONCLUSION

Tet 5-20 mumol L-1 decreased the production of collagen and HA without obvious toxity on HLF, suggesting that Tet could be a hopeful anti-fibrosis drug.

[The effect of calmodulin antagonist on the anticancer effect of vinblastine]

Calmodulin exists in all eukaryotic cells. It functions as the intracellular receptor of Ca, regulates various cellular physiological processes. We studied the effect of calmodulin antagonist W-7 on the anti-cancer effects of vinblastine. With the method that calmodulin can activate cyclic nucleotide PDE, we found that W-7 can significantly reduce the calmodulin level of MGC803 cell (P < 0.05). W-7 could not only increase the uptaking and accumulating of -3H-Vinblastine in MGC803 cells (P < 0.05), but also decrease the IC50 of Vinblastine (from 12.0 +/- 0.03 nmol to 5.27 +/- 0.02 nmol) in MGC803 cells. It is indicated that calmodulin antagonist W-7 can enhance the anticancer effect of vinblastine.

A periplasmic intermediate in the extracellular secretion pathway of Pseudomonas aeruginosa exotoxin A

Pseudomonas aeruginosa exotoxin A is synthesized with a secretion signal peptide typical of proteins whose final destination is the periplasm. However, exotoxin A is released from the cell without a detectable periplasmic pool, suggesting that additional determinants in this protein are important for recognition by a specialized machinery of extracellular secretion. The role of the N terminus of the mature exotoxin A in this recognition was investigated. A series of exotoxin A proteins with amino acid substitutions for the glutamic acid pair at the +2 and +3 positions were constructed by mutagenesis of the exotoxin A gene. These N-terminal acidic residues of the mature exotoxin A protein were found to be important not only for efficient processing of the precursor protein but also for extracellular localization of the toxin. The mutated exotoxin A proteins, in which a glutamic acid at the +2 position was replaced by a lysine or a double substitution of lysine and glutamine for the pair of adjacent glutamic acids, accumulated in precursor forms in the mixed cytoplasmic and membrane fractions, which was not seen with the wild-type exotoxin A. The processing of the precursor form of one exotoxin A mutant, in which the glutamic acid at the +2 position was replaced with a glutamine, was not affected. Moreover, a substantial fraction of the mature forms of all three mutants of exotoxin A accumulated in the periplasm, while wild-type exotoxin A could be detected only extracellularly. The periplasmic pools of these variants of exotoxin A could therefore represent the intermediate state during extracellular secretion. The signal for extracellular localization may be located in a small region near the amino terminus of the mature protein or could consist of several regions that are brought together after the polypeptide has folded. Alternatively, the acidic residues may be important for ensuring a conformation essential for exotoxin A to traverse the outer membrane.

Distribution of materno-fetus materno-suckling transfer of tritium after single injection of tritiated water in mice

The metabolism and transfer of tritium from pregnant mice to fetus after injection of tritiated water intraperitoneally was investigated in this paper. The study was composed of three experiments. 1. Pregnant mice were injected with tritium water on the first day of pregnancy, in order to obtain a transfer coefficient of tritium from pregnant mice to fetus through placenta. 2. Pregnant mice were injected with tritiated water on the first day of parturition to study the transfer of tritium via mother milk from nursing mice to the baby-animals. 3. Pregnant mice were injected with tritiated water in different periods of gestation. The results showed that tritiated water was uniformly distributed in all of the tissues measured, including placenta, fetal membrane and amniotic fluid in experiment 1. No effect of placentas on tritium transfer from pregnant mice to fetus was found. Concentration of tritium in the baby's tissues was evidently higher than that in the pregnant mice in experiments 2 and 3, and the transfer coefficient in experiments 2 and 3 was generally higher than that in experiment 1.

Biokinetics of tritium incorporation into the tissues of rats during continuous ingestion of tritiated water or tritium-labeled food

Wistar strain male rats were continuously given tritiated water or tritiated wheat as drinking water or food for 70 days. During the ingestion, the tritium incorporation into rat tissues was examined in both wet and dry samples of liver, kidney, testis and blood. The concentration of organically bound tritium (OBT) in dry tissues of rats exposed to tritiated water (HTO) and 3H-food (tritiated wheat) attained an equilibrium within 2-3 weeks after the exposure. The concentration of OBT in dry tissues of rats exposed to HTO also reached an equilibrium within 3-4 weeks after the exposure. However, rats exposed to 3H-food, except for the liver, such an equilibrium state was not reached in other tissues and the OBT concentrations increased gradually throughout the exposure. The relative concentrations of total 3H and OBT at the end of the chronic ingestion of 3H food (70 day), expressed in percentages of the total activity were 1 and 9 times higher than those in rats exposed to HTO, respectively. In both groups, OBT as well as total 3H was almost uniformly distributed among the tissues examined.

A proline residue near the amino terminus of the mature domain of secretory proteins lowers the level of the proton motive force required for translocation

A large variety of proOmpF-Lpps, hybrid secretory proteins composed of the signal region of proOmpF and the mature part of the major lipoprotein, either possessing or not possessing a proline residue near the amino terminus of their mature domains, were constructed at a DNA level, and the rates of their in vitro translocation were determined in the presence and absence of the proton motive force (delta muH+). A proline residue at the signal peptide cleavage site (position +1) blocked the cleavage reaction but not the translocation reaction. All the proOmpF-Lpps examined exhibited approximately the same translocation rate in the presence of delta muH+ irrespective of the presence or absence of a proline residue near the amino terminus. In the absence of the delta muH+, which was achieved by either depletion of the respiratory substrate or the use of urea-treated membrane vesicles permeable to protons, proOmpF-Lpps possessing a proline residue near the amino terminus of the mature domain were translocated whereas those possessing no proline residue in this region were not translocated at all or only very weakly. The position of the proline residue was then moved stepwise away from the amino terminus of the mature domain. The further the position was moved away, the slower was the rate of translocation in the absence of delta muH+. The removal of the proline residue at position +2 of the mature domain of proOmpA also made the delta mu(H+)-independent translocation appreciably slower. It is suggested that the conformational flexibility endowed by the proline residue on the junction region between the signal peptide and the mature domain allows the translocation in the absence of delta muH+ and that this junction region must take on a particular conformation for initiation of the translocation reaction.

[Significance of serum procollagen-III-peptide in reflecting the therapeutic effects of calcium-channel blockers on hepatic fibrosis]

Changes in serum procollagen-III-peptide (PIIIP) and intravenous tryptophan tolerance test (ITT) were studied in 121 patients with liver cirrhosis during a follow-up period of up to 18 months. The patients received either nifedipine (31 cases, 60 mg/day), verapamil (28 cases, 120 mg/day), cinnarizine (29 cases, 150 mg/day) or tetrandrine (33 cases, 150 mg/day). The significant changes were found in ITT in any of the four drugs administrated for over three months. Serum PIIIP concentration decreased significantly in patients under tetrandrine therapy for 18 months (12.06 +/- 3.91 ng/ml vs 16.57 +/- 5.69 ng/ml before treatment). These data suggest that tetrandrine therapy may have favourable effects on hepatic fibrosis and improvement of liver function in liver cirrhosis.

Intravenous tryptophan tolerance test for liver function

An intravenous tryptophan tolerance test (ITrpTT) was designed for liver function since 95% Trp is metabolized by the liver. After an intravenous loading dose of 4 mg/kg body weight, serum levels of both free (F) and total (T) Trp were determined at 45 and 60 minutes. In normal controls and nonhepatic-disease patients, F45 (60) and T45 (60) did not exceed 7 mumol/L and 80 mumol/L, respectively, and F/T ratio not greater than 0.14. These were set up as cutoffs of upper normal limits. The test was abnormal in 87.5% of chronic persistent hepatitis (CPH) characterized by elevation of T45 (60), 100% of chronic active hepatitis (CAH) by elevation of F45 (60) and/or T45 (60), and 100% of hepatic cirrhosis by increase in F45 (60) and F/T ratio but not in T45 (60). The test seems to be more sensitive than the conventional tests for liver function. However, one should be cautious in interpretation of the test as there are some factors which might influence the Trp metabolism like exercise, alcoholism, corticosteroids and enzyme-inducers. It merits as an indication of liver dysfunction only when these factors are considered and excluded.