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Lymphatic remodeling in tumor microenvironments correlates with progression and metastasis, and local lymphatic vessels play complex and poorly understood roles in tumor immunity. Tumor lymphangiogenesis is associated with increased immune suppression, yet lymphatic vessels are required for fluid drainage and immune cell trafficking to lymph nodes, where adaptive immune responses are mounted. Here, we examined the contribution of lymphatic drainage to tumor inflammation and immunity using a mouse model that lacks dermal lymphatic vessels (K14-VEGFR3-Ig mice). Melanomas implanted in these mice grew robustly, but exhibited drastically reduced cytokine expression and leukocyte infiltration compared with those implanted in control animals. In the absence of local immune suppression, transferred cytotoxic T cells more effectively controlled tumors in K14-VEGFR3-Ig mice than in control mice. Furthermore, gene expression analysis of human melanoma samples revealed that patient immune parameters are markedly stratified by levels of lymphatic markers. This work suggests that the establishment of tumor-associated inflammation and immunity critically depends on lymphatic vessel remodeling and drainage. Moreover, these results have implications for immunotherapies, the efficacies of which are regulated by the tumor immune microenvironment.

Foxp3(+)CD4(+) regulatory T cells (Treg) have a crucial role in controlling CD4(+) T-cell activation, proliferation, and effector function. However, the molecular mechanisms regulating Treg function remain poorly understood. Here we assessed the role of IL-7, a key cytokine regulating T-cell homeostasis, in suppressor capacity of Treg. Using a skin allograft model in which transplant acceptance is controlled by the number of transferred Treg, we find that Treg impair the proliferation of allogeneic CD4(+) T cells, decrease production of IFNγ by effector T cells, and prevent early and increase late IL-7 induction by lymph node stromal cells. Increased IL-7 availability enhanced Treg survival, stabilized Treg molecular signature, enhanced surface IL-2Rα expression, and improved IL-2 binding of Treg, which diminished proliferation of alloreactive CD4(+) T cells. Sequestration of IL-7 or impairment of IL-7R signaling after allograft transplantation abolished Treg-mediated tolerance by limiting their suppressive capacity. Aged Il7rα-ΔTreg mice displayed mild symptoms of autoimmunity correlating with impaired expansion of effector Treg in response to IL-2. Thus, IL-7R signaling on Treg supports the functional activity of effector Treg by increasing their IL-2 sensitivity in the lymph node during peripheral and allograft tolerance.

Secondary lymphoid organs including lymph nodes are composed of stromal cells that provide a structural environment for homeostasis, activation and differentiation of lymphocytes. Various stromal cell subsets have been identified by the expression of the adhesion molecule CD31 and glycoprotein podoplanin (gp38), T zone reticular cells or fibroblastic reticular cells, lymphatic endothelial cells, blood endothelial cells and FRC-like pericytes within the double negative cell population. For all populations different functions are described including, separation and lining of different compartments, attraction of and interaction with different cell types, filtration of the draining fluidics and contraction of the lymphatic vessels. In the last years, different groups have described an additional role of stromal cells in orchestrating and regulating cytotoxic T cell responses potentially dangerous for the host. Lymph nodes are complex structures with many different cell types and therefore require a appropriate procedure for isolation of the desired cell populations. Currently, protocols for the isolation of lymph node stromal cells rely on enzymatic digestion with varying incubation times; however, stromal cells and their surface molecules are sensitive to these enzymes, which results in loss of surface marker expression and cell death. Here a short enzymatic digestion protocol combined with automated mechanical disruption to obtain viable single cells suspension of lymph node stromal cells maintaining their surface molecule expression is proposed.

The study of T cell responses and their consequences during allo-antigen recognition requires a model that enables one to distinguish between donor and host T cells, to easily monitor the graft, and to adapt the system in order to answer different immunological questions. Medawar and colleagues established allogeneic tail-skin transplantation in mice in 1955. Since then, the skin transplantation model has been continuously modified and adapted to answer specific questions. The use of tail-skin renders this model easy to score for graft rejection, requires neither extensive preparation nor deep anesthesia, is applicable to animals of all genetic background, discourages ischemic necrosis, and permits chemical and biological intervention. In general, both CD4(+) and CD8(+) allogeneic T cells are responsible for the rejection of allografts since they recognize mismatched major histocompatibility antigens from different mouse strains. Several models have been described for activating allogeneic T cells in skin-transplanted mice. The identification of major histocompatibility complex (MHC) class I and II molecules in different mouse strains including C57BL/6 mice was an important step toward understanding and studying T cell-mediated alloresponses. In the tail-skin transplantation model described here, a three-point mutation (I-A(bm12)) in the antigen-presenting groove of the MHC-class II (I-A(b)) molecule is sufficient to induce strong allogeneic CD4(+) T cell activation in C57BL/6 mice. Skin grafts from I-A(bm12) mice on C57BL/6 mice are rejected within 12-15 days, while syngeneic grafts are accepted for up to 100 days. The absence of T cells (CD3(-/-) and Rag2(-/-) mice) allows skin graft acceptance up to 100 days, which can be overcome by transferring 2 x 10(4) wild type or transgenic T cells. Adoptively transferred T cells proliferate and produce IFN-γ in I-A(bm12)-transplanted Rag2(-/-) mice.

Pancreatic islet transplantation has been proposed as an attractive option for the treatment of type I diabetes. Transplantation into different sites has been investigated, among them those that are immuno-logically privileged (e.g., thymus, uterus, brain, anterior eye chamber, and testicle). Because of their characteristics, seminal vesicles could be considered as immunologically privileged organs, but there is no worldwide experience that can confirm it. The purpose of the present study is to assess the viability and functionality of islet transplantation into seminal vesicles of diabetic rats. One hundred ninety inbred adult male syngeneic Lewis rats were used as donors (n = 72), receptors (n = 36), and controls(n = 11). Diabetes was chemically induced through a single intraperitoneal injection of streptozotocin. Groups of 1200 purified islets were introduced in the right seminal vesicle of diabetic rats. Diabetic control rats were sham transplanted. Body weight and glycemia were monitored every 2 d. Of transplanted rats, 16.7% achieved a good function due to islet engraftment, while 30.6% achieved a partially good response, and 52.7% were considered as nonresponding. This is the first report about islet transplantation into seminal vesicles of diabetic animals. Our results indicate that islet transplantation into rat seminal vesicles is technically possible, and that islets can function normally after engraftment into the wall of the seminal vesicle.

Background: Sentinel node biopsy (SNB) has been proposed as an alternative to axillary lymph-node dissection (ALND) in breast cancer. Before implementing SNB in our practice, we wished to test its validity by comparing it to the standard ALND, both in our hands and with other reported series., Patients and Methods: One hundred thirty-two patients were included prospectively. SNB and immediate ALND were performed. For SNB, a technetium-colloid was used to produce preoperative lymphoscintigraphy and intraoperative gamma-probe search for the SN. Serial sectioning and immunostains were used on the SN. A comprehensive review of the literature was done in order to run a meta-analysis of diagnostic tests using a summary receiver operating characteristic curve (SROC) to calculate the pooled parameters of sensitivity and associated 95% confidence interval (95% CI), including our own data., Results: Our technical success rate was 96%. Local sensitivity was 96%, with a 95% CI from 85%-99%. Seven patients were upstaged by the SNB. A literature search identified 18 studies published from 1996-1999. Estimates of sensitivity ranged from 83%-100%. The pooled data meta-analysis gave a global sensitivity of 91%, with a 95% CI from 89%-93%. The area under the global SROC curve was 0.9967., Conclusions: The minimally invasive SNB was shown to be a practical alternative to ALND. We propose to use local as well as global sensitivity and associated 95% CI to test the validity of SNB in the clinical setting. Due to limitations of ALND as the golden standard, SNB can in fact be considered a more accurate method for nodal staging.

Objectives: To study the incidence of band erosion in patients who have undergone vertical banded gastroplasty and to describe the reparative techniques used., Design: A retrospective review case series., Setting: A university hospital-based tertiary referral center., Patients: Two hundred fifty consecutive morbidly obese patients who underwent vertical banded gastroplasty between 1987 and 1995., Main Outcome Measures: The development of band erosion into the stomach, reparative surgical techniques, and long-term weight loss control., Results: Band erosion developed in 7 (2.8%) of the patients. Two patients had symptoms 1 month after undergoing forced endoscopy. Six patients required reoperation. The operative findings included 2 cases of "external" band erosion through the lesser curvature into the stomach and 4 cases of "internal" band erosion through the circular staple line. The surgical techniques used for repair depended on the radiological and endoscopic data and on the operative findings; the techniques included conversion into a gastric bypass, band replacement after the creation of a new stoma, and gastroplasty plus distal gastric bypass. There were no complications, and adequate long-term weight loss was achieved in all but 1 of the patients who underwent reoperation., Conclusion: Band erosion may be corrected using appropriate surgical techniques to allow for adequate long-term weight loss in patients who have undergone vertical banded gastroplasty.

Unlabelled: Obesity as a condition, and morbid obesity as a disease, have at present reached epidemic proportions. Bariatric surgery is the most effective treatment in those patients in whom medical, dietary, and/or behavioral treatments have failed. What is more, it is the initial treatment of choice in morbid superobese patients (> 50 kg/m2). The present study summarizes and criticizes the main surgical techniques used at present, and purposes an action protocol for anesthesia, as well as some norms and advice on control, action, and pulmonary and dietary rehabilitation, in the peri- and post operative period, based on more than 7 years' experience with a series of more than 150 operated and controlled patients., Conclusion: A restrictive bariatric technique is a model which allows the multidisciplinary obesity treatment team to achieve a definite and permanent modification of the eating habits of all patients who meet the criteria for inclusion in a surgical protocol.

Bariatric surgery is done on a selected, ill patient (morbid obesity), with a surgical risk which is intrinsic to his condition and morbidity. The results on any program are more a function of the adequate selection, information and control, than of the surgical model itself. The first 125 patients of the present surgical series have been reviewed, with a minimum of 18 months of follow up, and the complications are detailed, with emphasis on the compulsory and necessary radiological evaluation in the immediate post-operative period, during the follow up, and in the face of any complication. The effectiveness criteria of the technique and the real value of the weight loss are reevaluated, as well as defining the criteria of failure of surgical treatment. Finally, we end with an up dating of the psychological results observed, as well justifying the need for a bariatric surgery protocol, with its ethical-legal implications. The final conclusion is that bariatric surgery shall only be clinically and ethically accepted if it complies with the principles for which it was designed.

Somatostatin and endoscopic sclerotherapy are widely used in the treatment of acute variceal bleeding. Although objective evidence does exist about the advantages of either treatment, data comparing both procedures are scarce. In order to compare the effectiveness and safety of somatostatin and sclerotherapy in the treatment of acute variceal bleeding, 70 consecutive cirrhotic patients suffering from esophageal variceal hemorrhage and meeting the inclusion criteria were randomly assigned to treatment with somatostatin (35 patients) or sclerotherapy (35 patients). No differences in age, sex, alcohol intake, etiology of cirrhosis and severity of liver failure were found between groups. Failure of treatment (defined as persistence of bleeding despite therapy or subsequent rebleeding within the 48-hr trial period) occurred in seven patients (20%) in the somatostatin group and in six (17.1%) in the sclerotherapy group (NS). Early rebleeding occurred in seven of 28 patients (25%) in the somatostatin group and in five of 29 (17.2%) in the sclerotherapy group (NS). Mortality within the first 6 wk was no different between both groups: 10 (28.5%) and eight (22.8%) in the somatostatin and sclerotherapy groups, respectively. Sclerotherapy, but not somatostatin, was associated with major complications in five cases (14.2%) (p = 0.026), two of which resulted in patient's death. These results suggest that somatostatin is safer, and as effective as sclerotherapy, in controlling acute variceal bleeding until an elective treatment can be established.

Background: In the present study the year experience of a multidisciplinary team (oncologic, unit for the acquired immunodeficiency syndrome, and surgery) with the use of a new method of central intravenous administration of medication such as that of subcutaneous venous reservoirs (SVR) is reviewed., Methods: The subcutaneous injection capsules were implanted as a venous access in 150 surgical procedures in 146 patients from October 1985 to April 1991 with a total follow up of 29.190 days and a mean length of 251 days for SVR. Sixty-two percent (94 implantations) of the SVR were implanted in the out patient clinic, 20% (30 patients) were admitted for placement of the reservoir although this was only indicated in the first two years of the series, 13% (20 patients) during hospitalization for the base disease and only 4% (6 patients) were specifically admitted for surgical preparation (plasma, platelets, and others). SVR were used for chemotherapy (124 cases, 82%), repeated transfusions (6 cases, 4%) and chronic medication (acquired immunodeficiency syndrome, infections) (30 patients, 20%). Forty-two percent permitted chemotherapy administration by continual transfusion on an out patient regime., Results: A series of mechanical complications (3 cases, 2%), septic (9 episodes in 7 patients, 5%) and thrombotic (8 of the catheter) (5%) and 4 of the central veins (2%) were observed. In the present series the rate of infections (5%) (0.072 episodes of bacteremia per 100 days/patient) and thrombosis (3%) was very low due to a strict protocol of maintenance and control by the medical team and hospital staff. The need for radiologic control during surgery is emphasized although, as demonstrated in the present review, the technique of localization by a cath-finder (external detector) permits greater speed with the same security., Conclusions: The degree of patient satisfaction and the minimum incidence of serious complications in determined risk groups (neutropenia, acquired immunodeficiency syndrome) demonstrates that subcutaneous venous reservoirs (SVR) constitute an excellent method as a chronic venous access. The SVR present a lower rate of complications if compared with any historic series of external vascular catheterization.