The Southern Ocean Exchange: porous boundaries between humpback whale breeding populations in southern polar waters.

Humpback whales (Megaptera novaeangliae) are a cosmopolitan species and perform long annual migrations between low-latitude breeding areas and high-latitude feeding areas. Their breeding populations appear to be spatially and genetically segregated due to long-term, maternally inherited fidelity to natal breeding areas. In the Southern Hemisphere, some humpback whale breeding populations mix in Southern Ocean waters in summer, but very little movement between Pacific and Atlantic waters has been identified to date, suggesting these waters constituted an oceanic boundary between genetically distinct populations. Here, we present new evidence of summer co-occurrence in the West Antarctic Peninsula feeding area of two recovering humpback whale breeding populations from the Atlantic (Brazil) and Pacific (Central and South America). As humpback whale populations recover, observations like this point to the need to revise our perceptions of boundaries between stocks, particularly on high latitude feeding grounds. We suggest that this "Southern Ocean Exchange" may become more frequent as populations recover from commercial whaling and climate change modifies environmental dynamics and humpback whale prey availability.

Cost-effectiveness of selective internal radiation therapy using yttrium-90 resin microspheres in treating patients with inoperable colorectal liver metastases in the UK.

OBJECTIVE: Selective internal radiation therapy (SIRT) using SIR-Spheres(®) (90)Y-labeled resin microspheres has been shown to be a well-tolerated, effective treatment in patients with inoperable liver-dominant chemotherapy-refractory metastatic colorectal cancer (mCRC). This study estimated the cost-effectiveness of (90)Y-resin microspheres compared to best supportive care (BSC) from a UK perspective. METHODS: Survival data from a comparative retrospective cohort study was analyzed and used in a state-transition cost-effectiveness model, using quality-adjusted life years (QALYs) gained as the measure of effectiveness. The model incorporated costs for the SIRT procedure, monitoring, further treatment, adverse events, and death. Utility values, reflecting patient quality-of-life, were taken from a published source. RESULTS: SIRT using (90)Y-resin microspheres compared to BSC improved overall survival by a mean of 1.12 life years and resulted in a cost per QALY gained of £28,216. In sensitivity analysis, this varied between £25,015-£28,817. CONCLUSION: In an area of large unmet need, treatment with (90)Y-resin microspheres offers a clinically effective and cost-effective treatment option.

A new catheter for tumor targeting with radioactive microspheres in representative hepatic artery systems. Part I: impact of catheter presence on local blood flow and microsphere delivery.

Building on previous studies in which the transport and targeting of (90)Y microspheres for liver tumor treatment were numerically analyzed based on medical data sets, this two-part paper discusses the influence of an anchored, radially adjustable catheter on local blood flow and microsphere delivery in an idealized hepatic artery system (Part I). In Part II a patient-inspired case study with necessary conditions for optimal targeting of radioactive microspheres (i.e., yttrium 90) onto liver tumors is presented. A new concept of optimal catheter positioning is introduced for selective targeting of two daughter-vessel exits potentially connected to liver tumors. Assuming laminar flow in rigid blood vessels with an anchored catheter in three controlled positions, the transient three-dimensional (3D) transport phenomena were simulated employing user-enhanced engineering software. The catheter position as well as injection speed and delivery function may influence fluid flow and particle transport. Although the local influences of the catheter may not be negligible, unique cross-sectional particle release zones exist, with which selectively the new controlled targeting methodology would allow optimal microsphere delivery. The insight gained from this analysis paves the way for improved design and testing of a smart microcatheter (SMC) system as well as new investigations leading to even more successful treatment with (90)Y microspheres or combined internal radiation and chemotherapy.

A new catheter for tumor-targeting with radioactive microspheres in representative hepatic artery systems--part II: solid tumor-targeting in a patient-inspired hepatic artery system.

In this second part, the methodology for optimal tumor-targeting is further explored, employing a patient-inspired hepatic artery system which differs significantly from the idealized configuration discussed in Part I. Furthermore, the fluid dynamics of a microsphere supply apparatus is also analyzed. The best radial catheter positions and particle-release intervals for tumor targeting were determined for both the idealized and patient-inspired configurations. This was accomplished by numerically analyzing generated particle release maps (PRMs) for ten equally spaced intervals throughout the pulse. As in Part I, the effects of introducing a catheter were also investigated. In addition to the determination of micro-catheter positioning and, hence, optimal microsphere release, a microsphere-supply apparatus (MSA) was analyzed, which transports the particles to the catheter-nozzle, considering different axial particle injection functions, i.e., step, ramp, and S-curve. A refined targeting methodology was developed which demonstrates how the optimal injection region and interval can be determined with the presence of a catheter for any geometric configuration. Additionally, the less abrupt injection functions (i.e., ramp and S-curve) were shown to provide a more compact particle stream, making them better choices for targeting. The results of this study aid in designing the smart micro-catheter (SMC) in conjunction with the MSA, bringing this innovative treatment procedure one step closer to implementation in clinical practice.

Survival of colorectal cancer cell lines treated with paclitaxel, radiation, and 5-FU: effect of TP53 or hMLH1 deficiency.

Clonogenic survival and early cell death during treatment of human colon carcinoma cells were investigated following X-irradiation (IR) alone, IR followed by 5-FU for 24 h, and Taxol administered 24 h before IR and 5F-U. The investigated cell lines were: HCT116, 40-16 clonally derived from HCT116, and two HCT116 variants: N6CHR3 expressing hMLH1, and TP53 null cells denoted HCT116 p53-/-. The objective was to determine efficacy of the combined treatment and to correlate response with constitutive levels of TP53, WAF1, and hMLH1 proteins, as well as with mRNA levels of the apoptosis-related genes survivin, BNIP3, and MYC. At the end of treatment with 5-FU, the proportion of viable cells was between 0.65 and 0.70 for all cell lines. Additional cell loss occurred in 40-16 and HCT116 p53-/- cells following administration of Taxol before IR and 5-FU. Radiation sensitivity was unaffected by combined treatments, except for Taxol, irradiation, and 5-FU sequence in the HCT116 p53-/- and 40-16 cell lines, where radiation sensitivity determined by clonogenic survival curve slopes was doubled or quadrupled, respectively. Under our present experimental conditions, treatment response did not correlate with TP53 or hMLH1 status, but was associated with apoptosis-related genes, most notably BNIP3. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 175-185 (2000).

Use of radiation therapy in posttransplant lymphoproliferative disorder (PTLD) after liver transplantation.

Posttransplant lymphoproliferative disorder (PTLD) is a common and life-threatening complication of immunosuppression used to prevent rejection of solid organ and bone marrow transplants. There is no standardized treatment algorithm, but numerous management strategies are available. We describe a patient who developed a solitary lymphoproliferative lesion in the porta hepatis 9 months after orthotopic liver transplant. Following reduction in immunosuppression with no response, she was treated with involved field radiotherapy utilizing CT-based treatment planning. A partial radiographic response was obtained, and she has not developed disease in the engrafted liver or systemically. Based on the present case report, involved field radiotherapy seems to be a reasonable treatment option for patients with localized PTLD. Int. J. Cancer (Radiat. Oncol. Invest.) 90:104-109, 2000.

High dose rate brachytherapy to prevent recurrent benign hyperplasia in lung transplant bronchi: theoretical and clinical considerations.

BACKGROUND: Significant anastomotic stenosis and malacia is reported to affect 7% to 15% of lung transplant recipients. Laser debridement, dilation and stenting can be used effectively to treat the majority of these patients. However, persistent, as well as reactive hyperplastic tissue reaction, will occur in some of these patients, requiring multiple bronchoscopic interventions. The experience of 2 patients who received intraluminal brachytherapy irradiation to prevent recurrence of hyperplastic tissue causing airway obstruction is reported. Both had failed multiple attempts of local control, including wall stent, laser ablation and balloon dilation. They suffered from shortness of breath and progressive decrease in quality of life because of airway obstruction. METHODS: Two patients received intraluminal irradiation immediately following removal of severe post-lung transplant obstruction. Both patients developed airway obstruction 3 to 4 months after left lung transplantation. High Dose Rate (HDR) brachytherapy (192Ir). Afterloader was used to treat Patient 1 on two occasions. Patient 2 required a single treatment. The radiation dose of 3Gy/fraction was calculated at 1 cm from the catheter for all applications. RESULTS: Follow up for both patients included bronchoscopy at 3 weeks, 3 months and 6 months after radiation therapy. Follow up for Patient 1 is 7 months, and patient 2 is 6 months. Each patient had an initial complete response after radiation. There were no treatment-related complications, and both patients experienced significant improvement in respiratory function. CONCLUSIONS: Symptomatic benign airway obstruction from hyperplastic tissue in the bronchus after lung transplantation can be successfully treated with intraluminal radiation therapy. Patients who develop recurrent benign granulation tissue after stent and laser therapy may be considered for this type of treatment.

Comparison of three treatment options for single brain metastasis from lung cancer.

Whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and the combination of both treatment methods were used for the management of single brain metastasis from lung cancer. The purpose of this study is to compare these three different treatment options in terms of local response, survival, and quality of life. From June 1995 to July 1998, 70 lung cancer patients with new diagnosed single brain metastasis were treated with either WBRT alone (n = 29), or SRS alone (n = 23), or the combination of both methods (n = 18). Multiple endpoints, including survival, freedom from local progression (FFLP), freedom from new brain metastasis (FFNBM), local control, Karnofsky performance status (KPS), and causes of death, were measured from the date of treatment completion and compared using univariate and multivariate analyses. For patients treated with WBRT-alone, SRS-alone, and SRS+WBRT, the median survivals were 5.7, 9.3, and 10.6 months, the median FFLP were 4.0, 6.9, and 8.6 months, the median FFNBM were 4.1, 6.7, and 8.6 months, and the local response rates were 55.6, 87.0, and 88.9%, respectively. Four of the 29 patients treated with WBRT-alone continued with progression of disease. The post treatment KPS showed improvement in 41.4, 82.6, and 88.9% of patients treated with WBRT-alone, SRS-alone, and SRS+WBRT, respectively. The progression of new and/or recurred metastatic brain tumor as the cause of death accounted for 51.7%, 50. 0%, and 28.3% of the patients treated with WBRT-alone, SRS-alone, and SRS+WBRT, respectively. Univariate analyses showed that the significant differences among the three treatment arms were observed based on all of the above mentioned endpoints. However, the comparison between SRS-alone and SRS+WBRT groups indicated that adding WBRT only improves FFNBM (P = 0.0392). Cox regression analyses revealed no significant difference in both of the KPS (P = 0.1082) and causes of death (P = 0.081) among the three arms. Both SRS alone and SRS+WBRT seem better in prolonging life and improving quality of life than WBRT alone for patients with single brain metastasis from lung cancer. But the combined therapy did not show significant advantage over SRS alone in improving survival, enhancing local control, and quality of life except for a more favorable FFNBM. Further investigation via a randomized trial is needed to access the value of adding WBRT to SRS in the management of this group of patients. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 37-45 (2000).

Utility of radiation in the prevention of heterotopic ossification following repair of traumatic acetabular fracture.

PURPOSE: Heterotopic ossification (HO) is a common problem following surgical repair of traumatic acetabular fracture (TAF), potentially causing severe pain and decreased range of motion. This report analyzes the role of radiation therapy for prevention of HO in TAF. METHODS AND MATERIALS: The charts of all patients who received RT to the hip following TAF repair between July 1988 and January 1998 were reviewed. Sixty-six patients were identified. RT was given in 5 fractions of 2 Gy in 45 patients, 1 fraction of 8 Gy in 17 patients, and other doses in 4 patients. Treatment fields encompassed periacetabular tissues at highest risk for HO. Time to RT was < or = 24 hours for 46 patients. RESULTS: Radiographic follow-up at least 6 months following RT was available in 47/66 (71%) patients to permit Brooker classification, revealing 6 cases (13%) of Grade III HO, compared to historical incidence in this population of 50%. No Grade IV HO was found. Mean follow-up was 18 months. Four of the Grade III patients had received 10 Gy/5 fractions, and 2 received 8 Gy/1 fraction. Postoperative wound infection occurred in 6 patients, and osteonecrosis of the femoral head was found in 13. CONCLUSIONS: RT following surgical repair of TAF provides effective prophylaxis against formation of clinically significant HO. We recommend a single fraction of 7-8 Gy within 24 hours of surgery to prevent HO formation and minimize patient discomfort.

Pimonidazole: a novel hypoxia marker for complementary study of tumor hypoxia and cell proliferation in cervical carcinoma.

BACKGROUND: Tumor hypoxia may be associated with treatment resistance, cell proliferation, and metastatic potential, which contribute to poor prognosis. Complementary techniques for detecting hypoxia, cell growth, and metastases are required to study these relationships. OBJECTIVES: The purpose of this study was to demonstrate the clinical feasibility of quantitative hypoxia detection with pimonidazole, a novel hypoxia marker, and to correlate hypoxia with S-phase markers of tumor proliferation. METHODS: Pimonidazole binds to thiol-containing proteins specifically in hypoxic cells. Ten patients with cervical carcinoma received 0.5 g/m2 pimonidazole intravenously followed by biopsy of the cervical carcinoma the next day. Hypoxic cells were recognized by immunohistochemical detection of pimonidazole using a mouse monoclonal antibody. Cell proliferation was detected with a commercially available monoclonal antibody for proliferating cell nuclear antigen (PCNA). Assessment of hypoxia and cell proliferation was made qualitatively with light microscopy and quantitatively using point counting and image analysis software methods. RESULTS: No clinical toxic effects were associated with pimonidazole administration. Immunostaining with pimonidazole antibody was observed in 9 of 10 tumors, suggesting that hypoxia is a common occurrence in cervical carcinoma. Quantitatively, tumors that had large numbers of hypoxic cells had the greatest percentage of S-phase cells, but some tumors with smaller amounts of hypoxia also had substantial numbers of S-phase cells. CONCLUSION: Pimonidazole can be used for qualitative and quantitative assessment of tumor hypoxia.

Proliferation and hypoxia in human squamous cell carcinoma of the cervix: first report of combined immunohistochemical assays.

PURPOSE: To characterize the distribution of hypoxia and proliferation in human squamous cell carcinoma of the cervix via an immunohistochemical approach prior to initiation of therapy. METHODS AND MATERIALS: Patients with primary squamous cell carcinoma of the cervix uteri received a single infusion of the 2-nitroimidazole, pimonidazole (0.5 g/m2 i.v.), and 24 h later punch biopsies of the primary tumor were taken. Tissue was formalin fixed, paraffin embedded, and sectioned for immunohistochemistry. Hypoxia was detected by monoclonal antibody binding to adducts of reductively activated pimonidazole in malignant cells. Staining for endogenous MIB-1 and PCNA was detected in tumor cells via commercially available monoclonal antibodies. Point counting was used to quantitate the fraction of tumor cells immunostained for MIB-1, PCNA, and hypoxia marker binding. RESULTS: Immunostaining for pimonidazole binding was distant from blood vessels. There was no staining in necrotic regions, and only minimal nonspecific staining, mostly in keratin. In general, cells immunostaining for MIB-1 and PCNA did not immunostain for pimonidazole binding. Cells immunostaining for MIB-1 and PCNA showed no obvious geographic predilection such as proximity to vasculature. Quantitative comparison showed an inverse relationship between hypoxia marker binding and proliferation. CONCLUSIONS: Immunohistochemical staining for pimonidazole binding is consistent with the presence of hypoxic cells in human tumors and may be useful for estimating tumor hypoxia prior to radiation therapy. Immunostaining for pimonidazole binding is an ideal complement to immunohistochemical assays for endogenous proliferation markers allowing for comparisons of tumor hypoxia with other physiological parameters. These parameters might be used to select patients for radiation protocols specifically designed to offset the negative impact of hypoxia and/or proliferation on therapy. The inverse relationship between pimonidazole binding and proliferation markers is a preliminary result requiring verification.

Primary squamous cell carcinoma of the endometrium: a first report of adjuvant chemoradiation.

Primary squamous cell carcinoma of the endometrium is very rare, with only 49 cases reported in the literature. In 1928 Fluhmann proposed three criteria to establish the diagnosis: (1) no coexisting endometrial adenocarcinoma, (2) no connection between the endometrial tumor and the squamous epithelium of the cervix, and (3) no squamous cell carcinoma of the cervix present. The median age at presentation is similar to adenocarcinoma of the endometrium. Although most patients have presented with FIGO stage I disease, long-term survival has been dismal despite surgery and radiation therapy. We report a new case treated with postoperative radiation and cisplatin and review the literature.

Magnetic resonance imaging as a monitor of changes in the irradiated rat brain. An aid in determining the time course of events in a histologic study.

RATIONALE AND OBJECTIVES: Optimal dose schedules and total dose of ionizing radiation for human central nervous system malignancy are not known. An animal model has been developed for the investigation of rat central nervous system response to proton irradiation using magnetic resonance imaging (MRI). A clinical MRI device was used to monitor the response of the rat brain after irradiation as a possible indicator for histologic injury as a function of time and dose. METHODS: Single-dose fractions of protons were delivered to the left brain of 25 adult Sprague-Dawley rats. T1- and T2-weighted images were obtained using a 1.5-T MRI device via a 12-cm diameter coil at 4- to 6-week intervals after irradiation. Coronal images were evaluated by visual inspection and relaxation maps comparing the control and irradiated hemispheres. Histologic review was conducted on all rats' brains after death. RESULTS: Proton irradiation was delivered successfully to only the left brain of the animals. Histologic review confirms the location and extent of tissue damage demonstrated on MRIs obtained in vivo. Statistically significant differences were seen in the T2-weighted relaxation times in the irradiated cerebral hemisphere compared with the unirradiated hemisphere. CONCLUSION: The proton hemibrain rat model can be used to test treatment schedules of irradiation for central nervous system response using MRI to noninvasively document early and late effects within the same animal.

Decortication for childhood empyema. The primary provider's peccadillo.

Of the 31 children treated for empyema thoracis secondary to pneumonitis at the Loma Linda University Medical Center, Loma Linda, Calif, from 1980 to 1990, 23 responded to prompt directed antibiotic therapy coupled with drainage, usually tube thoracostomy. All patients were cured clinically; some demonstrated residual pleural reaction with chest roentgenography or computed tomography that resolved over time. Decortication was necessary in eight severely ill children; three required concurrent lung resection for abscess. Distinct from the nonoperated group, there was a pattern of initial antibiotic trials in these patients averaging 6.5 different drugs plus delayed drainage of effusions. Delay in the initiation of antibiotic therapy was six times longer for the operated vs the nonoperated group. Delay to tube thoracostomy was 18 days for the decorticated children compared with 5.4 days for the nondecorticated children. All eight children responded completely and rapidly to their decortications. Roentgenographic changes lagged considerably behind the clinical course of the child, and computed tomographic scans provided better identification of chest tube placement but little information predictive of the need for decortication. Decortication for empyema seldom is necessary when a child is treated promptly with appropriate antibiotics directed by thoracentesis findings, and drainage, usually tube thoracostomy. The criterion for decortication is persistent sepsis, not the roentgenographic appearance of the chest.