Investigation of MR image distortion for radiotherapy treatment planning of prostate cancer

MR imaging based treatment planning for radiotherapy of prostate cancer is limited due to MR imaging system related geometrical distortions, especially for patients with large body sizes. On our 0.23 T open scanner equipped with the gradient distortion correction (GDC) software, the residual image distortions after the GDC were <5 mm within the central 36 cm x 36 cm area for a standard 48 cm field of view (FOV). In order to use MR imaging alone for treatment planning the effect of residual MR distortions on external patient contour determination, especially for the peripheral regions outside the 36 cm x 36 cm area, must be investigated and corrected. In this work, we performed phantom measurements to quantify MR system related residual geometric distortions after the GDC and the effective FOV. Our results show that for patients with larger lateral dimensions (>36 cm), the differences in patient external contours between distortion-free CT images and GDC-corrected MR images were 1-2 cm because of the combination of greater gradient distortion and loss of field homogeneity away from the isocentre and the uncertainties in patient setup during CT and MRI scans. The measured distortion maps were used to perform point-by-point corrections for patients with large dimensions inside the effective FOV. Using the point-by-point method, the geometrical distortion after the GDC were reduced to <3 mm for external contour determination and the effective FOV was expanded from 36 cm to 42 cm.

Phase II study of gemcitabine in children with relapsed acute lymphoblastic leukemia or acute myelogenous leukemia (ADVL0022): a Children's Oncology Group Report

BACKGROUND

To determine the response rate and toxicity to gemcitabine administered as 10 mg/m2/min x 360 min weekly for 3 weeks in children with relapsed acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML). Gemcitabine is a deoxycytidine analog that inhibits DNA synthesis and repair and has a broad spectrum of antitumor activity.

PROCEDURE

From April 2001 to April 2003, 23 male and 9 female eligible patients were recruited for the Children's Oncology Group (COG) phase II study of Gemcitabine (ADVL0022).

RESULTS

One of 20 evaluable patients with ALL and none of 10 evaluable patients with AML had complete responses to gemcitabine; there were no partial responses. Grade 3 or 4 hematologic toxicity and liver toxicity were common during therapy. Only one patient was alive 1 year after entry. The estimated 1-year overall survival probability for the 32 patients was 4% (SE = 3%).

CONCLUSIONS

Gemcitabine at the dose and schedule in this trial was not effective for children with relapsed AML or ALL.

Unilateral low-frequency stimulation of central piriform cortex delays seizure development induced by amygdaloid kindling in rats

Low-frequency stimulation of the kindling site interferes with the course of kindling epileptogenesis. The present study examined the effect of unilateral low-frequency stimulation of the central piriform cortex on seizure development induced by amygdaloid kindling in rats. The ipsilateral or contralateral central piriform cortex received low-frequency stimulation (15 min train of 0.1 ms pulses at 1 Hz and 50-150 muA) immediately after termination of once daily kindling stimulation (2 s train of 1 ms pulses at 60 Hz and 150-300 microA) in the right amygdala for 30 days. Low-frequency stimulation of either the ipsilateral or contralateral central piriform cortex significantly suppressed the progression of seizure stages and reduced afterdischarge duration throughout the course of amygdaloid kindling. The marked suppression induced by low-frequency stimulation of the central piriform cortex on either side was predominantly due to the significant retardation of progression from stage 0 to stage 1 and stage 3 to stage 4 seizures. In addition, the suppressive effect of low-frequency stimulation did not disappear when the stimulation was stopped; it could persist for at least 10 days. These findings indicate that brain areas other than the kindling focus, such as the central piriform cortex on both sides, can also be used as reasonable targets for low-frequency stimulation to retard seizure development induced by amygdaloid kindling. Secondly, like the ipsilateral central piriform cortex, the contralateral central piriform cortex may also participate in the progression and secondary generalization of focal seizures. The study suggests that unilateral low-frequency stimulation of the central piriform cortex may have a significant antiepileptogenic effect, and may be helpful for exploring effective and long-lasting therapies for human temporal lobe epilepsy.

Vitrification of Carotid Artery Segments: An Integrated Study of Thermophysical Events and Functional Recovery Toward Scale-Up for Clinical Applications

In recent years, ice-free cryopreservation by vitrification has been demonstrated to provide superior preservation of tissues compared with conventional freezing methods. To date, this has been accomplished almost exclusively for small model systems, whereas cryopreservation of large tissue samples-of a clinically useful size-continues to be hampered by thermomechanical effects that compromise the structure and function of the tissue. Reduction of mechanical stress is an integral condition of successful cryopreservation of large specimens. The current study focuses on the impact of sample size on both the physical events, observed by cryomacroscopy, and on the outcome on tissue function. To this end, the current study sought to address the question of functional recovery of vitrified carotid artery segments, processed as either artery rings (3-4 mm long) or segments (25 mm long) as selected models; the latter model represents a significant increase in sample size for evaluating the effects of vitrification. Tissue vitrification using an 8.4 M cryoprotectant cocktail solution (VS55) was achieved in 1-ml samples by imposing either a high (50-70 °C/min) or a low (2-3 °C/min) cooling rate, between -40°C and -100°C, and a high rewarming rate between -100°C and -40°C. Following cryoprotectant removal, the artery segments were cut into 3 to 4-mm rings for function testing on a contractility apparatus by measuring isometric responses to four agonist and antagonists (norepinephrine, phenylepinephrine, calcium ionophore, and sodium nitroprusside). In addition, nonspecific metabolic function of the vessel rings was determined using the REDOX indicator alamarBlue. Contractile function in response to the agonists norepinephrine and phenylepinephrine was maintained at the same level (350%) for the segments as for the rings, when compared with noncryopreserved control samples. Relaxation in response to the antagonists calcium ionophore and sodium nitroprusside was maintained at between 75% and 100% of control levels, irrespective of cooling rate or sample size. No evidence of macroscopic crystallization or fractures was observed by cryomacroscopy at the above rates in any of the samples. In conclusion, this study verifies that the rate of cooling and warming can be reduced from our baseline vitrification technique such that the function of larger tissue samples is not significantly different from that of smaller blood vessel rings. This represents a step toward the goal of achieving vitreous cryopreservation of large tissue samples without the destructive effect of thermal stresses.

Gene expression profile of transgenic mouse kidney reveals pathogenesis of hepatitis B virus associated nephropathy

Hepatitis B virus (HBV)-associated nephritis has been reported worldwide. Immune complex deposition has been accepted as its pathogenesis, although the association between the presence of local HBV DNA and viral antigen and the development of nephritis remains controversial. To understand better the roles played by HBV protein expression in the kidney, the global gene expression profile was studied in the kidney tissue of a lineage of HBV transgenic mouse (#59). The mice expressed HBsAg in serum, and HBsAg and HBcAg in liver and kidney, but without virus replication. Full-length HBV genome (adr subtype, C genotype) isolated from a chronic HBV carrier was used to establish the transgenic mice #59. Similarly manipulated mice that did not express HBV viral antigens served as controls. Southern blotting, hybridization with HBV probe, and immuno-histochemical staining were used to study HBV gene expression. mRNA extracted from the kidney tissue was analyzed using Affymetrix microarrays. HBsAg and HBcAg were located mainly in the cytoplasm of tubular epithelium. Altogether 520 genes were "up-regulated" more than twofold and 76 genes "down-regulated" more than twofold in the kidney. The complement activation, blood coagulation, and acute-phase response genes were markedly "up-regulated". Compared to the controls, the level of serum C3 protein was decreased in #59 mice, while the level of C3 protein from kidney extract was increased. Results indicate that expression of HBsAg and HBcAg in tubular epithelial cells of the kidney per se can up-regulate complement-mediated inflammatory gene pathways, in addition to immune complex formation.

Functional duality of merlin: A conundrum of proteome complexity

Merlin and ezrin proteins belong to the same gene family, i.e., MERM containing merlin, ezrin radixin and moesin. Members of this family possess an extensive homology in their amino acid sequences. It has been shown that merlin is a tumor suppressor, while ezrin is a promoter in tumor progression. The expression of these two proteins is commonly found inversely proportional to each other in cancer cells, i.e. down-regulation of merlin concomitant with over-expression of ezrin and vice versa. However, when determining merlin and ezrin in ovarian carcinoma cells, we have observed that both merlin and ezrin could be over-expressed simultaneously in some ovarian cancer (OVCA) cell lines and OVCA ascites cells, suggesting that merlin could be an oncoprotein rather than a tumor suppressor protein in certain OVCA cells. The functional duality of merlin might represent a paradigm in proteome complexity and is especially important in investigating multifactorial diseases such as cancer.

Prognostic factors for women with Stage 1 ovarian cancer with or without adhesions

OBJECTIVE

To identify those prognostic factors in women with Stage 1 epithelial ovarian cancer that predict survival.

METHODS

A population-based cohort study was conducted which included all newly diagnosed ovarian cancer patients treated initially with surgery from 1996-1998 in Ontario, Canada (N = 1,341). We abstracted charts from hospitals and cancer centres and used hospital and billing claims databases. Cox survival analysis was used to model the association between prognostic factors (including patient characteristics, surgical findings, pathologic findings and subsequent treatment) and survival for those with Stage 1 ovarian cancer.

RESULTS

327 women had Stage 1 or 2 ovarian cancer (where Stage 2 was based on adhesions alone). Prognostic factors that had significant, unadjusted, association with survival were patient age, presence or absence of adhesions, grade, and surface involvement. The multivariable model that best described survival included premenopausal age group (HR 0.32, 95% CI, 0.18-0.55), poor differentiation (HR 2.17, 95% CI, 1.33-3.51), and surface capsule involvement (HR 2.97, 95% CI, 1.59-5.55). A lack of influence of treatment modality stands in contrast to the literature.

CONCLUSIONS

Our dataset confirmed that poor grade and surface capsule involvement are poor prognostic factors. Adjuvant therapy did not confer an improved outcome; however, it was likely used in only those patients with poor prognostic indicators and so improved their survival to that of women with good prognostic factors who received surgery alone.

Adolescents' attachment style and early experiences: a gender difference

We examined gender differences in perceived rearing and adult attachment style in adolescents. A total of 3,912 senior college students (1,149 men and 2,763 women) ages 18-23 (men's M = 20.1 years, women's M = 20.0 years) were administered a set of questionnaires including Relationship Questionnaire (to measure adult attachment), the Parental Bonding Instrument (perceived rearing), and a list of early life events. In the men, positive adult total attachment style was predicted by the scores of paternal care and low scores on maternal overprotection in a hierarchical regression analysis. On the other hand, in the women, positive adult total attachment style was predicted by the scores of paternal and maternal care, and low score on maternal overprotection. Adult attachment was also predicted by fewer Peer Victimization experience as a child in both men and women. However, while men's adult attachment was predicted by Self Disease experiences, women's adult attachment was predicted by Top Star experiences and fewer Relocation experiences. The adult attachment style was predictable from early experiences but there existed some gender differences.

Positive inductive effect of IL-2 on virus-specific cellular responses elicited by a PRRSV-ORF7 DNA vaccine in swine

This study investigated the effect of swine interleukin 2 (IL-2) and swine interleukin 4 (IL-4) on the development of immune responses induced by a PRRSV-ORF7 DNA vaccine (phCMV-ORF7). The two cytokines were cloned separately in the eukaryotic expression vector phCMV, and delivered via gene gun as adjuvants for the DNA vaccine. Groups of 3-week-old certified PRRSV-free, castrated male, Yorkshire crossbred pigs, were vaccinated with or without the IL-2 or IL-4. The ensuing humoral and cellular immune responses were analyzed by a PRRSV-specific ELISA, and by an in vitro blastogenic response of peripheral blood mononuclear cells (PBMC) stimulated by viral antigen, respectively. The animals were boosted 21 days post-vaccination and challenged 28 days afterward. The virus loads post-challenge were measured by real time PCR. The group of swine receiving the vaccine plus IL-2 had significant virus-specific blastogenic responses 3 weeks after the vaccine-cytokine boost, when compared to those of the experimental pigs that received the vaccine plus IL-4, vaccine alone, unvaccinated controls or the pigs vaccinated with the DNA vaccine cloned in the reverse orientation (phCMV-ORF7(Rev)). None of the experimental swine had detectable specific antibodies against the virus during the vaccination phase. The virus load peak in vaccinated animals was delayed by about 72h as compared to that of the control pigs (unvaccinated and vaccinated with the phCMV-ORF7(Rev) construct). Interestingly, animals that received the phCMV-ORF7 vaccine alone consistently had low virus loads throughout the study. These results demonstrate that IL-2 has a positive inductive effect on the activation of vaccine-induced virus-specific cellular immunity, while IL-4 appeared to have a suppressive effect. Our data also suggest that ORF7 may play a role in reducing the virus load in PRRSV infected animals.

Historical climate and stream flow trends and future water demand analysis in the Calgary region, Canada

The city of Calgary has been one of fastest growing cities in Canada in recent years. Rapid population growth and a warming climate trend have raised concerns about sustainable water supply. In this study, historic climate, stream flow and population data are analyzed in order to develop models of future climate trends and river-water resource availability. Daily water demands for the next 60 years were projected using the relationship between daily maximum temperature and water demand under simulated climate and population growth scenarios. To maintain sustainable growth Calgary will require water conservation efforts that reduce per capita water use to less than half of the current level over the next 60 years, an interval when the civic population is expected to be doubled.

Enhanced Tissue Strength in Cryopreserved, Collagen-Based Blood Vessel Constructs

Traditional cryopreservation methods do not adequately preserve complex natural or engineered multicellular tissues due to the ice formation in the extracellular matrices. Vitrification is an alternate ice-free method for cryopreservation. This study compares the effects of vitrification and conventional cryopreservation on an engineered blood vessel construct. Collagen-based vascular constructs were used as models in this study. Tubular constructs were cut into rings and distributed into fresh, frozen, and vitrified groups for evaluation of mechanical properties and cell viability. Passive mechanical tests revealed enhanced tissue strength after both freezing and vitrification. Cryosubstitution studies of frozen and vitrified constructs revealed negligible ice in the vitrified specimens and extensive ice formation in the extracellular matrix of frozen specimens. Morphological changes associated with ice formation were visible within tissues preserved using traditional cryopreservation but not in tissue preserved using vitrification. The metabolic assay results indicated that vitrified tissue had similar viability to fresh controls. These results suggest that the increased tissue strength after cryopreservation may relate to thermal property change during preservation that cross-link collagen in tissue-engineered blood vessels. Further development of this cryopreservation method is necessary to minimize the alteration in material property and maintain cell viability of the constructs.

Circulation DNA: biological implications for cancer metastasis and immunology

Circulation cell free DNA (cf-DNA) is of considerable interest to oncology researchers seeking to isolate specific cancer markers. Here, we focus on the origin and biological implications of cf-DNA, exploring its potential roles in cancer biology and medicine. We hypothesize that cf-DNA is primarily released by living cancer cells in addition to apoptotic or necrotic cancer cells for three reasons: (1) following radiotherapy, cf-DNA quantities are significantly reduced in a high percentage of patients although radiation-induced massive apoptosis is expected; (2) cancer cell DNA concentration in cultured supernatants increases with cell proliferation when few apoptotic or necrotic cells are present; and (3) DNA concentration increases in normal lymphocyte cultures following stimulation with phytohemagglutinin, lipopolysaccharide or antigen. Our hypotheses have major biological implications in cancer biology. First, cancer cf-DNA may transform normal cells and form adjacent or remote metastases or second primary cancer. In this context, we also have raised an alarming advice that the cancer may be potentially infectious. Secondly, if a normal cf-DNA contains cytokine sequence, it may behave like an intrinsic DNA vaccine, producing therapeutic cytokine. If normal cf-DNA contains a sequence of a non-mutated oncogene or tumor suppressor gene, homologous recombination with the cancer genome may occur leading to knock out mutated oncogene or tumor suppressor gene that could thus elicit a spontaneous remission of cancer.

Multiple intracranial aneurysms as delayed complication of atrial myxoma. Case report and literature review

SUMMARY

We report a case of multiple intracranial aneurysms as delayed complication of atrial myxoma.We reviewed the literature of intracranial myxomal aneurysms, and trying to find reasonable therapy methods, but got the conclusion that neurosurgery and interventional treatment were not helpful, chemotherapy and radiotherapy maybe useful in the treatment of such cases.

Dose rate constant of a Cesium-131 interstitial brachytherapy seed measured by thermoluminescent dosimetry and gamma-ray spectrometry

The aim of this work was to conduct an independent determination of the dose rate constant of the newly introduced Model CS-1 131Cs seed. A total of eight 131Cs seeds were obtained from the seed manufacturer. The air-kerma strength of each seed was measured by the manufacturer whose calibration is traceable to the air-kerma strength standard established for the 131Cs seeds at the National Institute of Standards and Technology (1 sigma uncertainty < 1%). The dose rate constant of each seed was measured by two independent methods: One based on the actual photon energy spectrum emitted by the seed using gamma-ray spectrometry and the other based on the dose-rate measured by thermoluminescent dosimeter (TLD) in a Solid Water phantom. The dose rate constant in water determined by the gamma-ray spectrometry technique and by the TLD dosimetry are 1.066 +/- 0.064 cGyh(-1)U(-1) and 1.058 +/- 0.106 cGyh(-1)U(-1), respectively, showing excellent agreement with each other. These values, however, are approximately 15% greater than a previously reported value of 0.915 cGyh(-1)U(-1) [Med. Phys. 31, 1529-1538 (2004)]. Although low-energy fluorescent x rays at 16.6 and 18.7 keV, originating from niobium present in the seed construction, were measured in the energy spectrum of the 131Cs seeds, their yields were not sufficient to lower the dose rate constant to the value of 0.915 cGyh(-1)U(-1). Additional determinations of the dose rate constant may be needed to establish an AAPM recommended consensus value for routine clinical use of the 131Cs seed.