Blue Dye Tracer Research Articles

Field study of macropore flow processes using tension infiltration of a dye tracer in partially saturated soils

AbstractMacropores are important preferential pathways for the migration of water and contaminants through the vadose zone. The objective of this study was to examine small‐scale preferential flow processes during infiltration in macroporous, low permeability soils. A series of tension infiltration tests were conducted using Brilliant Blue dye tracer at two field sites in southwestern Ontario, Canada. The maximum applied pressure head was varied for each test and the resulting dye stain patterns and macropore networks were characterized by excavation, mapping, photography, and image analysis. Worm burrows were the dominant macropore type, with average macropore densities exceeding 400 m−2 and peak densities of more than 750 m−2 at 30 cm depth at both sites. Flow in macropores became significant at infiltration pressures > − 3 cm, with corresponding increases in infiltration rate, soil water content variability (spatially and temporally), and depth of dye staining. The results demonstrated clear evidence for partially saturated macropore flow under porewater tension conditions and the associated importance of macropore–matrix interaction in controlling this flow. Field observations of transient infiltration showed that film and rivulet flow along macropores yielded vertical flow velocities exceeding 40 m d−1. Simple calculations showed that film flow along the walls and corners of irregularly shaped macropores could explain the observed results. Copyright © 2009 John Wiley & Sons, Ltd.

Neuroendocrine Proopiomelanocortin Neurons Are Excited by Hypocretin/Orexin

Hypocretin/orexin, produced by a group of neurons in the lateral hypothalamus/perifornical area, enhances cognitive arousal and also may play a crucial role in modulating the neuroendocrine system. How hypocretin modulates the endocrine system remains an open question. Hypocretin cells innervate the mediobasal hypothalamus where they can potentially influence the activity of specific cell populations within the arcuate nucleus. Here, we examine whether hypocretin modulates the median eminence-projecting proopiomelanocortin (POMC) neurons identified by selective green fluorescent protein expression and antidromic stimulation or retrograde Evans blue dye tracing in transgenic mice. We find that POMC neurons, in general, and, in addition, those that project their axons to the median eminence, were robustly activated by hypocretin in a dose-dependent manner. These excitatory actions included a threefold increase in spike frequency and direct membrane depolarization of up to 22 mV (mean, 17.9+/-7.2 mV). Direct postsynaptic depolarization was decreased at more positive membrane potentials, inhibited by the sodium-calcium exchanger antagonist KB-R7943, and reduced by lowering the bath temperature, or by buffering the postsynaptic calcium with BAPTA, suggesting that the primary mechanism for hypocretin-mediated excitation is the activation of the sodium-calcium exchanger. Hypocretin also enhanced excitatory inputs to POMC cells via a presynaptic mechanism and indirectly increased the release of GABA onto these cells in a spike-dependent manner. However, these synaptic actions were not necessary to cause postsynaptic membrane depolarization and spiking. Thus, in contrast to previous suggestions that hypocretin inhibited POMC cells, our results demonstrate robust direct excitation of POMC neurons by hypocretin.

The feasibility of sentinel lymph node biopsy in breast cancer patients after primary systemic therapy

Aims: Sentinel lymph node biopsy (SLNB) without axillary lymph node dissection (ALND) in SLN negative patients is a standard of care for most breast cancer patients. SLNB for axillary staging after primary systemic therapy (PST) is still contraindicated due to possibly reduced accuracy, while data are lacking. Purpose of this study was to evaluate the accuracy of SLNB after PST. Material and methods: 185 breast cancer patients were treated with PST, 160 patients received preoperative chemotherapy and 25 patients received preoperative endocrine therapy. 143/160 patients with preoperative chemotherapy and 22/25 patients with preoperative endocrine therapy were eligible for evaluation. The combination of blue dye and radioactive tracer was used for identification of SLNs. All patients received SLNB and axillary lymph node dissection (ALND). Results: Pathologic complete response rates and breast conserving therapy rates were 15% and 71.9% in the preoperative chemotherapy group and 0% and 72% in the preoperative endocrine therapy group, respectively. Identification rate, sensitivity, overall accuracy and false negative rate were 81.1% (116/143), 91.7% (55/60), 95.7% (111/116) and 8.3% (5/60) in the preoperative chemotherapy group and 77.3% (17/22), 90.0% (9/10), 94.1% (16/17) and 10.0% (1/10) in the preoperative endocrine therapy group, respectively. Conclusion: SLNB after primary systemic therapy is accurate and the results are comparable to those of primary SLNB. SLNB after PST could spare ALND in up to 40% of patients with primary positive axillary lymph nodes.

Metinel Node—The First Lymph Node Draining a Metastasis—Contains Tumor-Reactive Lymphocytes

BackgroundWe previously identified tumor-reactive lymphocytes in the first lymph nodes that drain the primary tumor. In this study, we performed lymphatic mapping to investigate the possibility of finding the first lymph nodes that drain metastases, and of learning whether these lymph nodes contained tumor-reactive lymphocytes suitable for adoptive immunotherapy.MethodsNineteen patients were studied. The primary tumor site was colorectal cancer in seven patients, malignant melanoma in four, ovarian cancer and breast cancer in two, and one each with pancreatic cancer, cholangiocarcinoma, leiomyosarcoma, and squamous cellular cancer of the tongue. By injection of Patent blue dye or radioactive tracers around the metastases, we identified draining lymph nodes from liver metastases (n = 9), intra-abdominal local recurrences (n = 3), and regional lymph node metastases (n = 7). In six patients, a preoperative lymphoscintigraphy was performed.ResultsWe located the first draining lymph node or nodes from metastases or local recurrences; we named them “metinel nodes.” Lymphocytes from the metinel nodes proliferated, showed clonal expansion, and produced interferon gamma (via in vitro expansions on stimulation with tumor homogenate) and interleukins, all of which demonstrate the characteristics of tumor-reactive lymphocytes. Eight of the nineteen patients received immunotherapy on the basis of tumor-reactive T cells derived from the metinel nodes.ConclusionsWe demonstrate that it is possible to locate the first lymph nodes draining subcutaneous, lymphatic, and visceral metastases, the so-called metinel nodes. Metinel node–derived lymphocytes may be used to treat disseminated solid cancer, and clinical trials should evaluate the effect of such treatment.

Sentinel-lymph-node biopsy in breast cancer

Sentinel-lymph-node (SLN) resection in operable breast cancer is a widely adopted and reliable staging instrument for lymphatic involvement. When undertaken by an experienced medical team (including a surgeon, nuclear physician, and pathologist (and when combined tracing techniques are used) ie, radioisotopes with blue-dye tracers) identification rate of SLNs has been shown to be over 95% with false-negative rates between 5% and 10% after subsequent axillary-lymph-node dissection (ALND).1 Clinical false-negative rates—ie, identification of positive lymph nodes during follow-up after a negative SLN procedure—have been reported as less then 1% after a mean follow-up of almost 4 years.

Tine-influenced infiltration patterns and informing timing of liquid amendment applications using brilliant blue dye tracers

Tillage associated with slurry applications, as well as soil physical properties at time of application, imparts strong control over resulting slurry application-induced infiltration patterns and contaminant flow pathways. This field-based study used Brilliant Blue-dyed water applied to tine-influenced silty-clay loam soil, at different antecedent soil water contents, to investigate the nature of infiltration patterns that might be expected to occur during a typical liquid manure or biosolid land application. The tines were associated with a furrow-based Kongskilde Vibro-Flex S-tine slurry application system and a soil pocket-forming AerWay ® SSD rolling aerator-type slurry application system. For the furrow-based approach, liquid was applied to a small furrow stretch at a nominal rate of 180,000 l ha −1 . For the AerWay treatment, a nominal liquid application rate of 180,000 l ha −1 was applied to individual soil pockets. Dye infiltration attributes were determined in 10 cm depth increments to over 1 m beneath the application area. Attributes included: dye infiltration depth, dye spread, and area coverage of dye. The attributes were determined for each depth via image processing software. Experiments were conducted at soil water conditions ranging from 15% v/v to 39% v/v. For furrow-based methods, dye was primarily absorbed above 30 cm depth (above a plough pan which, was approximately 20 cm depth) for all water content conditions. Dye spread:area ratios were generally larger below the pan than above it. Dye penetration depth for all water content conditions exceeded 60 cm depth. With the soil pockets caused by the AerWay treatments, the depth of dye penetration was non-linearly related to the soil water content where greatest dye penetration depth occurred at lower surface soil water contents ( 29% v/v). Overall, for the lower soil water content conditions, desiccation cracks and soil fractures facilitated by tillage action augmented bypass-based preferential flow to continuous sub-pan macropore networks. The greater infiltration depths achieved for the wetter soil conditions were due to greater intrinsic pore sizes that are operative at lower soil tensions and reduced dye sorption. The area covered by dye was greater above the plough pan; but beneath the pan, discrete macropore-based flow (e.g., worm burrows, root channels) dominated infiltration to the deepest observed depths as supported by observations of relatively higher dye spread:area ratios. This study underscores the importance of basing liquid amendment timing regulations not only on an upper water content limit but also on a lower limit as well. In addition, the study supports the impact of plough pans augmenting sorption in the tillage layer, thus minimising the degree of preferential flow to depth during a typical land application.

Intraoperative lymphatic mapping and sentinel node biopsy using hysteroscopy in patients with endometrial cancer

Objective The purpose of the study was to assess the feasibility of intraoperative sentinel node (SN) detection using injection of patent blue dye and radioactive tracer beneath the tumor of patients with endometrial carcinoma. Methods Hysteroscopy was used for injection of 2 ml of patent-V blue, followed by 20–50 MBq technetium-99 m-labelled nanocolloids into the subendometrial layer underlying the tumor of 60 patients with endometrial cancer. Then SN biopsy, pelvic and paraaortic lymphadenectomy, hysterectomy and bilateral salpingo-oophorectomy were carried out through laparotomy or laparoscopy. Results Sixty patients aged 43 years to 87 years (median age 65 years) were enrolled in this study. Sentinel nodes were identified in 49 of 60 patients (82%). The mean number of SN retrieved was 3.7 per patient (range, 1 to 8). Sixteen patients (33%) had SN in both pelvic and paraaortic areas. No patient had SN only at the paraaortic level. Metastatic disease was found in 9 patients (15%). In 8 of them at least one SN was positive. Conclusion Intraoperative sentinel node detection is feasible in patients with endometrial carcinoma using hysteroscopy for injection of blue dye and technetium-99 m beneath the tumor. This technique may actually enhance the chances of detecting metastatic disease, while reducing the extent of the surgery.

Validity of Sentinel Lymph Node Biopsy in Taiwanese Breast Cancer Patients

The clinical validity of sentinel lymph node (SLN) biopsy in Taiwanese breast cancer patients from 16 institutes in two consecutive periods was analyzed. Data from the initial period between January 3, 1999 and July 2004 and data from the later period after August 2004 to February 2005 were compared. Data on the use of a tracer, SLN identification, harvest and examination, false negative rate (FNR) and the number of patients spared axillary lymph node dissection (ALND) were analyzed. A total of 3308 patients with clinical axilla negative breast cancer underwent SLN biopsies in 16 hospitals (11 in both periods and 5 in the period before August 2004). Comparison of data from the two periods revealed that in the later period, use of combined blue dye and isotope tracer increased from 40% to 80%, the 95% SLN biopsy success rate increased from 50% to 80%, hospitals conducting intraoperative SLN examination increased from 80% to 93%, and the 95% match to permanent section rate increased from 30% to 80%. In the initial period, eight hospitals had less than 7% FNR, while in the later period this had decreased to 4.1% in these hospitals. Another three hospitals had FNR greater than 7% in the initial period, which had decreased to 0% in the later period. Hospitals with more than 100 cases of SLN biopsy had an average 3.8% FNR, whereas hospitals with less than 100 cases of SLN biopsy experience had an 8.2% FNR (p < 0.01). This study found that the SLN biopsy success rate increased after the use of combined tracers and with experience. FNR was controlled to within 5% among breast surgeons with accumulated experience exceeding 100 cases. It is recommended that ALND-sparing surgery be suspended temporarily in hospitals with FNR greater than 5%.

The Use of Periareolar Intradermal Tc-99m Tin Colloid and Peritumoral Intraparenchymal Isosulfan Blue Dye Injections for Determination of the Sentinel Lymph Node

The purpose of the present study was to evaluate the use of lymphoscintigraphy, blue dye, and gamma probe detection methods for determination of the sentinel lymph node (SLN) using both periareolar intradermal injection of Tc-99m tin colloid and peritumoral intraparenchymal injection of isosulfan blue dye. One hundred patients with T1-2 breast cancer and clinically negative nodes were enrolled in the present study. The study was composed of 2 groups. Backup axillary lymph node dissection (ALND) was mandatory in group 1 (20 patients) regardless of their lymph node status. In group 2 (80 patients), complete ALND was performed when intraoperative frozen section analysis of SLN revealed metastases. Otherwise, only SLN biopsy was performed without ALND. One day before surgery, Tc-99m tin colloid was injected at 4 periareolar sites intradermally. Lymphoscintigraphy was performed 1 to 2 hours after injection of the radiocolloid. Twenty minutes before surgery, isosulfan blue dye was injected into parenchyma surrounding the tumor or the biopsy cavity. The detection rates of SLN and false-negative rate of lymphoscintigraphy, blue dye, and gamma probe detection were 85%, 95% 100%, and 0% in group 1, 91%, 87%, and 95% in group 2, respectively. Detection rate by the combination of blue dye and radio tracer was 98%. According to the results of our study, we conclude that perioareolar intradermal injection of Tc-99m tin colloid combined with peritumoral intraparenchymal injection of blue dye is an accurate and easy method of locating the sentinel node with very high detection rates. It is recommended that the combination of all methods such as lymphoscintigraphy, blue dye, and gamma probe application will increase the success rate of SLN detection in patients with breast cancer.

Methylene blue dye versus combined dye-radioactive tracer technique for sentinel lymph node localisation in early breast cancer

Aim The study compared the accuracy and success rate of two techniques, methylene blue alone versus combined methylene blue and radioactive colloid in sentinel lymph node localisation in the management early breast cancer. Methods Three hundred and twenty-nine patients with tumours less than 2 cm on ultrasound assessment were prospectively evaluated. One hundred and seventy-three patients (Group A) underwent sentinel lymph node localisation using 1 ml of 1% methylene blue. A combined technique of both methylene blue and radioactive colloid was used in 156 patients (Group B). Application of both was subdermal and subareolar. Sentinel lymph nodes were examined by standard microscopy. Patients underwent breast conservation surgery or mastectomy and sentinel node guided four node axillary sampling ± clearance. Results In Group A, the sentinel lymph node identification rate was 96.5%. The negative predictive value was 96.3%, with false negative of 3.7% and accuracy of 87.4%. In group B the identification rate for sentinel lymph node was 98.7%, with false negative of 4.1%, negative predictive value of 96%, and accuracy of 83.8%. Conclusion Sentinel lymph node localisation using methylene blue or combined dye and radioactive tracer technique predicts the axillary lymph node status in early breast cancer with comparable success rates, accuracy and false negative rates. The combined technique facilitates quicker identification of sentinel lymph node; however the dye technique alone can be used successfully in centres without nuclear medicine facilities.

Is Blue Dye Indicated for Sentinel Lymph Node Biopsy in Breast Cancer Patients With a Positive Lymphoscintigram?

The use of isosulfan blue dye in sentinel node biopsy for breast cancer has been questioned because of its risk of allergic reaction. We hypothesized that blue dye could be safely omitted in the subgroup of patients who have evidence of successful sentinel node localization by lymphoscintigraphy. A retrospective review of patients with breast cancer and sentinel node biopsy was conducted. Information was collected on lymphoscintigraphy results, use of blue dye, and intraoperative and pathologic findings of sentinel nodes. We identified 475 patients with breast cancer who underwent 478 sentinel node biopsies. Both dye and isotope were given in 418 cases, of which 380 had a positive lymphoscintigram. In 5 of the 380 cases with a positive lymphoscintigram, the sentinel nodes obtained were blue but not hot, for a 1.3% marginal benefit of dye in the technical success of the procedure. Sentinel nodes positive for metastasis were found in 102 of 380 cases; in 3 cases, the only positive sentinel node was blue but not hot. Omission of the blue dye tracer would have increased the false-negative rate of the sentinel node procedure by approximately 2.5%. Even in sentinel node biopsy cases with a positive lymphoscintigram, the use of blue dye is beneficial for both improving the technical success of the procedure and reducing the false-negative rate of the procedure. Because the marginal benefits of dye justify its routine use, strategies to minimize the toxicity of blue dye are warranted.

Correlation Between Concordance of Tracers, Order of Harvest, and Presence of Metastases in Sentinel Lymph Nodes With Breast Cancer

There are various methods for the detection of sentinel lymph nodes (SLNs) in breast cancer by using a combined method with blue dye and radioisotope (RI) tracers. The purpose of the study was to reveal any correlation between concordance of the tracers and the order of harvest with the presence of metastases in SLNs. The outcomes were reviewed in 408 cases with stage 0 to II breast cancer; the combined method was used in which blue dye and RI were injected subcutaneously around the tumor. The radioactivity and blue staining in each harvested SLN were checked. In 330 cases (81%), SLNs contained both blue dye and RI tracers (blue-hot cases), and in 42 (10%) and 31 (8%) cases, the SLNs contained only the blue stain (blue-only cases) and only RI (hot-only cases), respectively. The overall metastatic rate was 25% on a patient basis. Blue-only cases had a higher rate (42%) of metastasis than hot-only cases (14%). The rate of nodes containing both blue dye and RI gradually decreased from the first SLNs harvested to the third SLNs harvested. The rate of nodes containing RI only increased with the number harvested, and there was not so much change in the rate of nodes containing blue only. These data suggest that RI tracer could detect a wide range of SLNs and that the blue dye tracer could efficiently detect SLNs with metastasis. The combined methods compensates for the deficiencies of each method and thus will probably help to prevent missing SLNs.

Laparoscopic Sentinel Lymph Node Mapping for Early Gastric Cancer

Sentinel lymph node (SLN) is known as the first possible site of metastasis along the route of lymphatic drainage from the primary cancerous lesion [1]. SLN mapping has been a focus of attention in management of various solid tumors to establish individualized minimally invasive surgery. In the fields of breast cancer and melanoma, several multicentric prospective randomized control trials for SLN biopsy are ongoing, and less invasive modified surgical approaches based on the SLN status have already been put into practice. However, the application of the SLN concept for gastrointestinal (GI) malignancies was not recognized until late 1990s because of high incidence of so-called skip metastasis. From the reports in recent years, we found that socalled skip metastases in GI cancers are attributed to the aberrant lymphatic drainage from the GI tract and the most of so-called skip metastases occurred in SLNs [2, 3]. Despite the multidirectional and complicated lymphatic flow from gastric mucosa, the anatomical situation of the stomach is better suited for SLN mapping than that of organs that are embedded in closed spaces, such as the esophagus and rectum. In particular, clinically T1N0 gastric cancer seems to be a good entity for which to try to modify the therapeutic approach. Several studies supporting the validity of the SLN concept for gastric cancers have been reported in the past 5 years in settings of open surgery [4,5,6]. Two major largescale clinical trials of SLN mapping for gastric cancer in open surgery have been started in Japan. The next important issue in this field is the introduction of laparoscopic SLN mapping for early gastric cancer, to establish novel minimally invasive surgery. Laparoscopic modified surgery based on SLN status would be the goal of a minimally invasive approach for pathologically nodenegative early gastric cancer. In this issue of World Journal of Surgery, Tonouchi and colleagues present a result of laparoscopic lymphatic mapping and SLN biopsy for early gastric cancer. It is reasonable to employ the dual-tracer method with blue dye and radioactive tracer for detection of SLNs in this study. Although there are several favorable reports of dye-guided SLN mapping for gastric cancer in open surgery, laparoscopic dye-guided SLN detection for gastric cancer is not feasible. Fast transit of blue dye (5–15 min for diffusion) is a restriction of dye-guided laparoscopic detection of multidirectional SLNs of gastric cancer. Technical errors using the single mapping agent approach are reduced by adding a different approach for lymphatic mapping. The radio-guided method allows us to confirm the complete harvest of SLNs with multidirectional and widespread distribution by gamma probing while the dye procedure enables us to perform real-time observation of the visualized lymphatic vessels. Therefore, we recommend a combination of dye and radioguided methods for systematic lymphatic mapping of gastric cancer as an optimal procedure at this moment. In the present study, the authors reported the case of a false negative study that resulted from a detection error [7]. Although the SLN concept was valid (the metastatic node was radioactive) in this case, the radioactive SLN was missed by laparoscopic gamma probing due to the shine-through effect. As shown in the article by Tonouchi, we have to pay attention to the remaining issues in laparoscopic application of this technology. Laparoscopic gamma probing is still under development, and there are several technical and material limitations. Available rigid-type laparoscopic gamma probes are fixed by entry-trocar, and the freedom to search for SLN and to avoid the shine-through effect from the injection site is seriously restricted. As we have seen several breakthroughs in the field of endoscopic surgery, development of new devices may provide a new frontier of this technology. Limitation of the sensitivity of intraoperative histological examination is another serious problem that can lead to false-negative studyies [8]. After overcoming these remaining issues, laparoscopic SLN mapping for early gastric cancer could be the leading model of individualized minimally invasive approaches for study of visceral solid tumors.

Blue dye versus combined blue dye—radioactive tracer technique in detection of sentinel lymph node in breast cancer

Background Sentinel lymph node biopsy in breast cancer can be used to select patients in which axillary lymph node dissection could be avoided. In this study we compared the value of two methods for identification of sentinel node (SN) using either only blue dye or combination of blue dye and radioactive tracer. Material and methods All patients were women with clinically T 1−2N 0M 0 breast cancer. They were randomized into two groups. In Group A (50 patients) SN marking was performed only with blue dye and in Group B (100 patients) combined SN marking with blue dye and radiotracer was done. We used 2 ml of blue dye Patentblau V ® (Byk Gulden). Radiotracer was Antimony sulfide marked with Tc 99m and of 0.3 mCy (11.1 MBq) activity. Application method of both contrasts was peritumoral. After SN biopsy all patients underwent mastectomy or conservative surgery with axillary lymph node dissection of levels I and II. Results In Group A mean of 1.7 SNs were identified (median 1, range 1–4). False-negative rate in this group was 3/17 (17.6%) with negative-predictive value 20/23 (86.9%), sensitivity 14/17 (82%), specificity 20/33 (60%) and accuracy 34/50 (68%). In Group B mean number of SNs excised per case was 1.6 (median 1, range 1–5). False-negative rate was 2/44 (4.5%), negative-predictive value 41/43 (95.3%), sensitivity 42/44 (95%), specificity 41/56 (73%) and accuracy 83/100 (83%). The combination technique was significantly superior to blue-dye alone technique for negative-predictive value ( p=0.033) and overall accuracy ( p=0.048). Conclusions The prediction of axillary lymph node status in breast cancer patients using combined technique has significantly higher accuracy than marking of SN with blue dye alone and therefore should be preferred.

A pilot study of sentinel lymph node scintigraphy in breast carcinoma

Objective To explore the significance of sentinel lymph node (SLN) in breast carcinoma with different methods. Methods Three hundred and thirty two patients with breast carcinoma were examined with blue dye and the combination of 99 Tc m sulfur colloid (SC) scintigraphy and blue dye tracing, respectively, in order to find the best way for identifying the SLN. Twenty five patients with tumor less than 3 cm in diameter were treated with SLN biopsy (SLNB) instead of axillary lymph node dissection (ALND) to compare the advantage of two therapies. Results SLNs were successfully identified in 325 of 332(97.8%) patients. The accuracy of SLNB for predicting axillary lymph node status was 94.2%, with 14.0% false negative rate. The success rate, accuracy and false negative rate in blue dye group and combination group were 96.7%, 92.2%, 21.6%, and 100%, 97.5%, 4.8%, respectively. The false negative rate in combination group was significantly lower than in blue dye group ( χ 2=7.91, P 0.01). No operation complications were found in all the patients undergone SLNB only. Conclusions In this study, SLNB accurately predicted the axillary status in breast carcinoma with clinically declared negative nodes; the combination method was superior than the blue dye method in identifying SLN; the extent of axillary surgical dissection was decreased significantly in SLNB only group, and a better outcome was obtained so far.

Visualization experiment to investigate capillary barrier performance in the context of a Yucca Mountain emplacement drift

The use of capillary barriers as engineered backfill systems to divert water away from radioactive waste potentially stored in a Yucca Mountain emplacement drift is investigated. We designed and conducted a flow visualization experiment to investigate capillary barrier performance in this context. A two-dimensional, thin slab, test system replicated the physical emplacement drift to one-quarter scale (1.4-m diameter) and included the simulated drift wall, waste canister, pedestal, capillary barrier backfill, and host-rock fracture system. Water was supplied at the top of the simulated drift and allowed to discharge by way of wicks located along the left wall of the cell (simulated fractures) or by a gravity drain at the bottom of the right side (simulated impermeable rock with floor drain). Photographs captured the migration of water and a blue dye tracer within the system, analytical balances measured the mass balance of water, while tensiometers measured the capillary pressure at numerous locations. Of particular concern to this test was the drainage of the capillary barrier, which terminates against the drift wall. We found that while the simulated fractures (left side) and drain (right side) each influenced the performance of the capillary barrier at early time, they had little differential affect at later times. Also of concern was the small disparity in capillary properties between the fine and coarse layer (limited by the need of a fine-grained material that would not filter into the coarse layer under dry conditions). While the capillary barrier was able to divert the majority of flow toward the edges of the system and away from the simulated waste canister, the barrier did not preclude flow in the coarse layer, which was noted to be visually wet next to the waste canister on day 92 and was continuing to take on water at termination on day 112.

Sentinel Node Biopsy: Standard of Care

Abstract: Sentinel lymph node biopsy (SLNB) is a less invasive alternative to axillary lymph node dissection (ALND) for staging breast cancer. In appropriate women, this procedure can stage the axilla with less extensive surgery and fewer complications. Sentinel node status is accurate in predicting axillary status based on single institutional experiences and confirmed by large multi-center trials. Non-sentinel nodes are involved very rarely if the sentinel node is tumor-free. SLNB enables intense examination of a single lymph node. However, the use of special stains to detect micrometastases is of uncertain clinical significance and is the subject of large trials. Early follow-up from the John Wayne Cancer Institute experience demonstrates excellent outcome for patients with either micrometastases or tumor-free nodes. Results from techniques with either blue dye or radioisotope colloid tracer and injection locations at peri-areolar, peritumoral, or subcutaneous sites are similar. These findings support the biological concept of a single (or very few) sentinel nodes for the entire breast. The sentinel node is more predictive of axillary status than any other tumor prognostic factor. Axillary lymph node dissection is unlikely to reveal nodal metastases when the sentinel node is tumor-free, and in such cases there is no reason to perform a completion axillary node dissection. Sentinel node biopsy alone without axillary lymph node dissection should now be the standard of care for most clinically node-negative women with breast cancer.

Sentinel node biopsy in 70 unselected patients with breast cancer: increased feasibility by using 10 mCi radiocolloid in combination with a blue dye tracer

AimsLymphatic mapping and sentinel node (SN) biopsy in breast cancer contribute to more accurate staging, while using less invasive techniques. The aim of this study is to improve the accuracy and feasibility of this concept, increasing the identification rate of the SN, by using an alternative technique.MethodsIn 70 unselected patients with primary breast cancer, of whom 51% had undergone previous excisional biopsy, lymphatic mapping was performed using 10 mCi (370 MBq)99mTc-nanocolloid peritumorally, combined with an intradermal blue dye tracer.ResultsLymphoscintigraphy showed one or more SN in 97% and harvest of the SN was possible in all patients (identification rate 100%). Axillary metastases were found in 39%. Sensitivity of the SN biopsy was high, both after primary surgery (93%) and after previous surgery (100%). Internal mammary lymph node biopsy following lymphatic mapping was attempted in all 24 patients (34%) with parasternal SN visible on the scan and was successful in 15 patients, revealing metastatic involvement in five patients.ConclusionsWe conclude that SN biopsy, using a higher dose of peritumoral radiocolloid tracer, combined with intradermal blue dye tracer, increases feasibility in breast cancer, making this concept applicable for all patients with primary breast cancer.

Sentinel Lymph Node Technique for Staging of Breast Cancer

Lymphatic mapping and sentinel lymphadenectomy is becoming an important surgical technique for assessing axillary status in breast cancer. In experienced hands, it can be successfully performed in >90% of cases. The morbidity of sentinel lymphadenectomy is minimal, considerably less than the 15%-20% rate of complications associated with axillary lymph node dissection. Moreover, excision of the sentinel node provides a specimen for focused histopathologic analysis and experimental studies using sensitive immunohistochemical techniques and even reverse transcriptase polymerase chain reaction, which may improve detection of axillary metastases. Intraoperative mapping of the lymphatic tract draining to the sentinel node may use vital blue dye and/or radioactive tracer. The rate of sentinel node detection exceeds 90% with either agent alone or in combination. Because definitive follow-up data are not yet available, intraoperative lymphatic mapping and sentinel lymphadenectomy should be considered an experimental staging adjunct rather than a therapeutic modality.

Point processes and random sets for analyzing patterns of methylene blue coloured soil

We consider the problem of quantitatively characterizing horizontal patterns of dye following infiltration. Such patterns display important information on the movement of possibly contaminated solutes from the soil surface to the ground water, which may cause risks for human health. The stains were made visible by means of methylene blue dye tracers. Different spatial statistical techniques are compared. First, a standard point pattern analysis is applied. Since the stains usually have a non-point type appearance, geostatistical techniques were used to account for positive areas. Next, more advanced point pattern techniques have been applied on replicate samples from different land management and land use types, focusing on the hazard rate for spatial patterns. As it turned out, point patterns analysis and geostatistics could be used in a complementary way, the point pattern analysis by considering colouring as basically generated by single points, the geostatistics by taking the spatial extension into account as well. The spatial hazard rate was useful to detect changes in the effects of land use.