Long-term outcome of laparoscopic rectopexy for full-thickness rectal prolapse.

BACKGROUND: The aim of this study was to assess the long-term outcomes of laparoscopic rectopexy for full-thickness rectal prolapse (FTRP). METHODS: Data of a prospectively maintained database were analysed. A structured telephone interview was conducted to assess a consecutive series of long-term outcomes of an unselected population who had laparoscopic rectopexy at a single centre between April 2006 and April 2014. The primary outcome was recurrence of FTRP. Secondary outcomes were functional outcomes and morbidity associated with the procedure. RESULTS: A total of 80 patients (74 female, median age of 66 years, range 23-96 years) underwent a laparoscopic rectopexy, of whom 35 (44%) were for recurrent prolapse. Seventy-two patients (90%) had a posterior suture rectopexy, six (8%) had a ventral mesh rectopexy, one (1%) had a combination of both procedures, and one (1%) had a posterior suture rectopexy with a sacrocolpopexy. There was no conversion to open surgery. Three patients (4%) needed reoperation within 30 days after surgery: two due to small bowel obstruction and one for a suspected port site hernia. Seventy-four patients (93%) were available for either clinical follow-up (FU) or telephone interview and there were 17 (23%) recurrences of FTRP at the median FU of 57 months (range 1-121 months). The median time to recurrence was 12 months (range 1-103 months). Recurrence of FTRP was seen in nine patients (12%) within 1 year following surgery. A history of multiple previous prolapse repairs increased the risk of prolapse recurrence (odds ratio 8.33, 95% confidence interval 1.38-50.47, p = 0.020). Based on clinical follow-up of 71 patients up to 1 year, there were 41 patients (58%) who had faecal incontinence prior to rectopexy of whom two patients (5%) had complete resolution of symptoms and 14 (34%) had improvement. CONCLUSIONS: Laparoscopic rectopexy is a safe operation for full-thickness rectal prolapse. The durability of the repair diminished over time, particularly for patients operated on for recurrent prolapse.

Physiological changes after colorectal surgery suggest that anastomotic leakage is an early event: a retrospective cohort study.

AIM: Anastomotic leakage (AL) is often identified 7-10 days after colorectal surgery. However, in retrospect, abnormalities may be evident much earlier. This study aims to identify the clinical time point when AL occurs. METHOD: This is a retrospective case-matched cohort comparison study, assessing patients undergoing left-sided colorectal resection between 2006 and 2015 at a specialist colorectal unit. Patients who developed AL (LEAK) were case-matched to two CONTROL patients by procedure, gender, laparoscopic modality and diverting stoma. Case note review allowed the collection of basic observation data and blood tests (leukocyte count, C-reactive protein, bilirubin, alanine transaminase, creatinine) up to postoperative day (POD) 4. The cohorts were compared, with the main outcome measure being changes in basic observation data. RESULTS: Of 554 patients, 49 developed AL. These were matched to 98 CONTROL patients. Notes were available for 105 patients (32 LEAK/73 CONTROL). Groups were similar in demographics, tumour or nodal status, preoperative radiotherapy, intra-operative air-leak integrity and drain usage. AL was detected clinically at a median of 7.5 days postoperatively. There was a significantly increased heart rate by the evening on POD 1 in LEAK patients (82.8 ± 14.2/min vs 75.1 ± 12.7/min, P = 0.0081) which persisted for the rest of the study. By POD 3, there was a significant increase in respiratory rate (18.0 ± 4.2/min vs 16.5 ± 1.3/min, P = 0.0069) and temperature (37.0 ± 0.4C vs 36.7 ± 0.3C, P = 0.0006) in LEAK patients. C-reactive protein was significantly higher in LEAK patients from POD 2 (165 ± 95 mg/l vs 121 ± 75 mg/l, P = 0.023). CONCLUSIONS: Physiological and biochemical changes associated with AL happen very early postoperatively, suggesting that AL may occur within 36 h after surgery, despite much later clinical detection.

Biological characteristics of an immunoregulatory activity secreted by an autoreactive CD4+ T cell clone that suppresses autoimmune diabetes in non-obese diabetic mice.

We previously reported the generation and characterization of a panel of CD4(+) autoreactive T cell clones that suppress development of autoimmune diabetes in non-obese diabetic (NOD) mice. We showed that the protective capacity of the T cell clones correlated with secretion of an activity that potently inhibits allogeneic mixed lymphocyte reaction (allo-MLR). In this report, we describe the biological characteristics of the allo-MLR inhibitory activity (MLR-IA, short for mixed lymphocyte reaction inhibitory activity) secreted by the protective T cell clone, NOD-5. MLR-IA has little effect on initiation of proliferation in an allo-MLR, but it potently inhibits the maintenance and amplification of the proliferative response. MLR-IA is also capable of inhibiting concanavalin A (Con A) stimulated splenic responder T cell proliferation. MLR-IA is reversible in vitro and is not restricted by MHC class I or II proteins. MLR-IA does not affect IL-2 receptor expression of responding T cells and has no effect on IL-2-dependent proliferation of CTLL-20 T cells. Partially purified MLR-IA inhibits IL-2 production in a primary allo-MLR, and decreases IFN-gamma production during secondary allo-MLR and Con A activation, whereas it enhances IL-4 production in both primary and secondary Con A activation. MLR-IA is not neutralized by combination of antibodies specific for transforming growth factor-beta, IL-10, tumor necrosis factor-alpha/beta or IFN-gamma, suggestive of a novel activity. MLR-IA is ammonium sulfate precipitable, sensitive to protease digestion and is destroyed by boiling, indicating that a protein moiety is part of its active structure. Our work suggests that a potentially novel immunoregulatory activity, capable of inhibiting T lymphocyte proliferation and IFN-gamma production, and stimulating IL-4 production, may regulate development of autoimmune diabetes in NOD mice.

CD4+ beta islet cell-reactive T cell clones that suppress autoimmune diabetes in nonobese diabetic mice.

We report the isolation of a panel of CD4+ T helper type 1 autoreactive T cell clones from the spleen of unprimed nonobese diabetic mice, a murine model of human insulin-dependent diabetes mellitus. The T cell clones express a diverse repertoire of T cell receptors, three of which recognize beta islet cell autoantigen(s). The islet cell-reactive T cell clones inhibit adoptive transfer of insulin-dependent diabetes mellitus and intraislet lymphocytic infiltration. The protective capacity of the T cell clones correlates with their ability to produce a novel immunoregulatory activity that potently inhibits in vitro allogeneic mixed lymphocyte reaction. The partially purified activity significantly inhibited the adoptive transfer of diabetes. Our work provides evidence in support of the existence of T helper type 1, CD4+ T cells reactive to beta islet cell autoantigens that have acquired a protective instead of a diabetogenic effector function. These T cells mediate their protective action in part by production of an immunoregulatory activity capable of down-regulating immune responses, and they are likely to represent a population of regulatory T cells that normally plays a role in maintaining peripheral tolerance.

Cytoplasmic tail deletion of T cell receptor (TCR) beta-chain results in its surface expression as glycosylphosphatidylinositol-anchored polypeptide on mature T cells in the absence of TCR-alpha.

Surface expression of the T cell antigen receptor (TCR) in mature T cells requires the association of a variable heterodimer (alpha.beta or gamma.delta) with six invariant CD3 polypeptides (gamma, delta, epsilon-epsilon, zeta-zeta, or zeta-eta). We described here that deletion of the cytoplasmic tail polypeptide sequence (Lys-Lys-Lys-Asn-Ser) of TCR beta-chain (beta CT) results in expression of the truncated beta-chain on the surface of a mature T cell hybridoma line, in the absence of TCR-alpha, as a glycophosphatidylinositol (GPI)-anchored monomeric polypeptide. The GPI-anchored TCR-beta CT is not associated with CD3-epsilon and is incapable of conventional signal transduction. Association with TCR-alpha prevents beta CT from GPI-linkage formation. The alpha beta CT heterodimer binds the CD3 polypeptides, and the resultant TCR alpha beta CT/CD3 complex is capable of signal transduction. Our data show that a signal sequence for GPI-linkage formation is present in TCR-beta, and this alternative membrane anchoring mechanism can be utilized by beta-chain polypeptide lacking the CT sequence. We conclude therefore that in the absence of TCR-alpha expression, the beta-chain CT sequence plays an essential function in hindering GPI-linkage formation, thereby preventing escape of incompletely assembled TCR beta-chain to the cell surface of mature T cells.

Genetic reconstitution of the T cell receptor (TcR) alpha/beta heterodimer restores the association of CD3 zeta 2 with the TcR/CD3 complex.

The cell surface expression of the T cell receptor (TcR)/CD3 complex and, consequently, the functional competence of the cell is partly dependent on CD3 zeta. In its absence, a pentameric complex (TcR alpha/beta/CD3 gamma delta epsilon) is formed which is inefficiently transported to the cell surface. Reconstitution of CD3 zeta by transfection, in turn, restores the cell surface expression and function of the complex. Through the use of transfection experiments, we here provide direct evidence that the association of CD3 zeta 2 with the TcR/CD3 complex is dependent on the presence of both the TcR alpha and beta polypeptide chains. Despite wild-type levels of the CD3 zeta protein in a TcR alpha-negative mutant human T cell line, a complex was formed intracellularly which lacked CD3 zeta 2 and consisted of beta gamma delta epsilon and beta 2 gamma delta epsilon. Upon transfection of the mutant with a TcR alpha cDNA, a TcR/CD3 complex which contained CD3 zeta 2 was observed intracellularly. In contrast to the partial subcomplex on the cell surface of the untransfected cell line, the TcR/CD3 complex on the transfectant was functional as demonstrated by its ability to mobilize intracellular calcium after stimulation with a mitogenic CD3 epsilon-specific monoclonal antibody. Transient transfection studies performed in COS cell fibroblasts indicated that CD3 zeta 2 was not interacting with the TcR alpha protein alone, implying that a conformation provided by either the TcR alpha/beta heterodimer or the TcR alpha/beta/CD3 gamma delta epsilon complex was necessary for the association of CD3 zeta 2. Transfection studies performed in a TcR alpha/beta-negative murine T-T hybridoma confirmed the requirement of both the TcR alpha and beta proteins in CD3 zeta 2 binding. We conclude that the TcR alpha and beta chains harbor polypeptide sequences essential for the association of CD3 zeta 2 with the TcR/CD3 complex.

Surface expression of CD3 in the absence of T cell receptor (TcR): evidence for sorting of partial TcR/CD3 complexes in a post-endoplasmic reticulum compartment.

The T cell receptor (TcR) for antigen, on the majority of T cells, is a disulfide-linked heterodimer composed of the alpha and beta chains, noncovalently associated with the CD3 complex of polypeptides (gamma, delta, epsilon and zeta). In this report, two murine thymoma cell lines are described which synthesized incomplete TcR/CD3 complexes and expressed low levels of CD3 on their surface in the absence of the TcR chains. The partial TcR/CD3 complexes were composed primarily of the inherently metabolically stable CD3 gamma and epsilon subunits. These results were in contrast to previous studies, which suggested that synthesis of all of the component chains of the TcR/CD3 complex is required for the successful transport of any of the chains to the cell surface. The efficiency of transport of the partial TcR/CD3 complexes from the endoplasmic reticulum (ER) to medial Golgi in the two thymomas was similar to complete complexes. However, the transport of the incomplete receptors was impaired at some point between the medial Golgi and the plasma membrane. Taken together with previous studies, these results suggested that T cells have mechanisms to retain partial TcR/CD3 complexes intracellularly both in the ER and in an undefined post-ER compartment. However, the transport of low levels of partial TcR/CD3 complexes to the cell surface in some T cell lines implied that the retention mechanisms may not always be completely efficient. Cross-linking of the surface, partial TcR/CD3 complexes with anti-CD3 epsilon antibodies did not stimulate interleukin 2 (IL 2) production. It is possible, however, that the partial TcR/CD3 complexes have some function which is unrelated to the stimulation of IL 2 production.

Voltage-dependent calcium channels in pituitary cells in culture. I. Characterization by 45Ca2+ fluxes.

Properties of Ca2+ transport activated by depolarization of the membrane potential were investigated in the GH4C1 strain of rat pituitary cells. Membrane potential was depolarized by increasing external K+ concentration and was determined by [3H]tetraphenylphosphonium+ distribution. Depolarization by 50 mM [K+]o increased the initial rate of 45Ca2+ uptake 5-fold and the steady state 45Ca2+ content 8-fold. Stimulated 45Ca2+ uptake was not inhibited by tetrodotoxin (2 X 10(-6) M), and was insensitive to external Na+ concentration. Stimulated 45Ca2+ uptake increased with increasing external Ca2+ concentration (for [Ca2+]o less than 10 mM) and could be described by a Langmuir type expression (KCa = 4.3 mM). Initial rates of 45Ca2+ uptake increased almost linearly between -51 and -30 mV, from 2 to 12 nmol/min/mg of protein, and a maximum of 14 nmol/min/mg of protein was reached at -12 mV beyond which 45Ca2+ influx decreased, and was 11 nmol/min/mg of protein at 0 mV. Ca2+ permeability, PCa, calculated from the Goldman-Hodgkin-Katz constant field expression increased almost linearly for a wide range of membrane potential (-51 to -20 mV) and began to level off at -6 mV. Activated 45Ca2+ uptake was completely inhibited by La3+, Co2+, Mn2+, Mg2+, nifedipine, and verapamil; K1/2 values for inhibition were 1.7 X 10(-7) M, 0.1 mM, 0.1 mM, 2 mM, 1.7 X 10(-8) M, and 2 X 10(-5) M, respectively, at 0.5 mM [Ca2+]o. Ba2+ could substitute for Ca2+ in the uptake mechanism. The increase in activated 45Ca2+ uptake was transient and was turned off with time. We conclude that the initial rate of K+-stimulated 45Ca2+ uptake measured under the experimental conditions described represents uptake via voltage-dependent Ca2+ channels. Knowledge of the properties of this channel in GH4C1 cells will be essential in elucidating its role in the Ca2+-dependent actions of thyrotropin-releasing hormone.