Assessment and optimization of liver volume before major hepatic resection: Current guidelines and a narrative review

Post hepatectomy liver failure (PHLF) remains a significant cause of morbidity and mortality after major liver resection. Although the etiology of PHLF is multifactorial, an inadequate functional liver remnant (FLR) is felt to be the most important modifiable predictor of PHLF. Pre-operative evaluation of FLR function and volume is of paramount importance before proceeding with any major liver resection. Patients with inadequate or borderline FLR volume must be considered for volume optimization strategies such as portal vein embolization (PVE), two stage hepatectomy with portal vein ligation (PVL), Yttrium-90 radioembolization, and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). This paper provides an overview of assessing FLR volume and function, and discusses indications and outcomes of commonly used volume optimization strategies.

IL-10 suppression of IFN-γ responses in tuberculin-stimulated whole blood from Mycobacterium bovis infected cattle

The measurement of bovine interferon-gamma (IFN-γ) forms the basis of a diagnostic test for bovine tuberculosis where Mycobacterium bovis sensitised effector T cells produce IFN-γ following in vitro stimulation with tuberculin antigens. In cattle infected with M. bovis it is also known that the anti-inflammatory IL-10 cytokine can inhibit in vitro production of IFN-γ leading to a reduced response in the IFN-γ diagnostic test. In order to investigate this in greater detail, whole blood samples from tuberculin skin test positive and negative cattle were stimulated with bovine and avian tuberculin antigens and in parallel with a neutralising anti-IL-10 monoclonal antibody. The results showed that IFN-γ protein levels increased when IL-10 activity was suppressed by Anti - IL-10. By using a standard diagnostic interpretation, the elevated levels of IFN-γ were shown to change the level of agreement between the performance of the single intradermal comparative tuberculin test (SICTT) and IFN-γ assay, depending on the tuberculin treatment. A transcriptomic analysis using RT-qPCR investigated the influence of IL-10 activity on expression of a suite of cytokine genes (IFNG, IL12B, IL10 and CXCL10) associated with antigen-stimulated production of IFN-γ. The IFNG and IL12B genes both experienced significant increases in expression in the presence of Anti-IL-10, while the expression of IL10 and CXCL10 remained unaffected.

Antigen-Specific IP-10 Release Is a Sensitive Biomarker of Mycobacterium bovis Infection in Cattle

The most widely used ante-mortem diagnostic tests for tuberculosis in cattle are the tuberculin skin test and the interferon-gamma (IFN-γ) release assay, both of which measure cell-mediated immune responses to Mycobacterium bovis infection. However, limitations in the performance of these tests results in a failure to identify all infected animals. In attempting to increase the range of diagnostic tests for tuberculosis, measurement of the cytokine IP-10 in antigen-stimulated blood has previously been shown to improve the detection of M. tuberculosis and M. bovis infection, in humans and African buffaloes (Syncerus caffer), respectively. In the present study, 60 cattle were identified by the single intradermal comparative tuberculin test as tuberculosis reactors (n = 24) or non-reactors (n = 36) and the release of IFN-γ and IP-10 in antigen-stimulated whole blood from these animals was measured using bovine specific ELISAs. There was a strong correlation between IP-10 and IFN-γ production in these samples. Moreover, measurement of the differential release of IP-10 in response to stimulation with M. bovis purified protein derivative (PPD) and M. avium PPD distinguished between reactor and non-reactor cattle with a sensitivity of 100% (95% CI, 86%–100%) and a specificity of 97% (95% CI, 85%–100%). These results suggest that IP-10 might prove valuable as a diagnostic biomarker of M. bovis infection in cattle.

Consensus Conference on North American Training in Hepatopancreaticobiliary Surgery: A Review of the Conference and Presentation of Consensus Statements

The findings and recommendations of the North American consensus conference on training in hepatopancreaticobiliary (HPB) surgery held in October 2014 are presented. The conference was hosted by the Society for Surgical Oncology (SSO), the Americas Hepato-Pancreatico-Biliary Association (AHPBA), and the American Society of Transplant Surgeons (ASTS). The current state of training in HPB surgery in North America was defined through three pathways-HPB, surgical oncology, and solid organ transplant fellowships. Consensus regarding programmatic requirements included establishment of minimum case volumes and inclusion of quality metrics. Formative assessment, using milestones as a framework and inclusive of both operative and nonoperative skills, must be present. Specific core HPB cases should be defined and used for evaluation of operative skills. The conference concluded with a focus on the optimal means to perform summative assessment to evaluate the individual fellow completing a fellowship in HPB surgery. Presentations from the hospital perspective and the American Board of Surgery led to consensus that summative assessment was desired by the public and the hospital systems and should occur in a uniform but possibly modular manner for all HPB fellowship pathways. A task force composed of representatives of the SSO, AHPBA, and ASTS are charged with implementation of the consensus statements emanating from this consensus conference.

Diagnosis of Mycobacterium bovis infection in cattle by use of the gamma-interferon (Bovigam®) assay

The strategic use of the gamma-interferon (IFN-gamma) assay (Bovigam) can provide a means for the early identification of Mycobacterium bovis infected cattle, thus ensuring their removal from an infected herd. When used in parallel with the tuberculin test, it is capable of identifying infected cattle, which might otherwise not be detected until later, if at all. The early detection and removal of these animals reduces the risk that they will become a source of infection for other cattle. When targeted in herds of high prevalence the benefits to the herd owner directly concerned can be considerable as the assay provides a means of shortening the period of restriction for such herds. This serves to generate confidence among herd owners and other stakeholders that effective schemes, based on sound scientific principles, can be developed to eradicate tuberculosis from infected cattle populations.

The effect of the tuberculin test and the consequences of a delay in blood culture on the sensitivity of a gamma-interferon assay for the detection of Mycobacterium bovis infection in cattle

The strategic use of the gamma-interferon (IFN-gamma) assay (Bovigam) can provide a means for the early identification of Mycobacterium bovis infected cattle, thus ensuring their removal from an infected herd. It has been reported that performance of the test can be influenced by various factors including a recent tuberculin skin test and the length of delay between collection and processing of blood samples. In this study, single intradermal comparative tuberculin test (SICTT) reactor and non-reactor cattle were recruited from herds infected with M. bovis and grouped according to their SICTT responses. Group 1 comprised reactor cattle selected on the basis of their SICTT response to PPD-bovine (purified protein derivative of tuberculin) exceeding that of PPD-avian by at least 12mm. Group 2 animals were selected from herds undergoing routine surveillance for bovine tuberculosis and contained standard SICTT reactor cattle (PPD-bovine exceeding that of PPD-avian by at least 4mm) and non-reactors. We investigated the effects of the SICTT on the assay results by measuring the in vitro IFN-gamma responses of Group 1 reactor cattle at time intervals pre- and post-skin test. No significant differences were measured in the IFN-gamma responses of the reactor animals to PPD-bovine and PPD-avian for up to 65 days. To investigate if a delay in processing of blood affected the performance of the assay, we compared results using duplicate blood samples from Group 1 and Group 2 cattle stimulated with PPD antigen at 8h and at 24h after collection. In both groups of animals the mean optical density (OD) values of the assay at 24h post-collection were significantly lower than those at 8h. Our results demonstrated that a delay in processing of the blood samples from cattle subjected to routine surveillance could significantly impact on the outcome of the IFN-gamma assay resulting in a change of the IFN-gamma status of the animals.

Wild-type NM23-H1, but not its S120 mutants, suppresses desensitization of muscarinic potassium current

NM23 (NDP kinase) modulates the gating of muscarinic K+ channels by agonists through a mechanism distinct from GTP regeneration. To better define the function of NM23 in this pathway and to identify sites in NM23 that are important for its role in muscarinic K+ channel function, we utilized MDA-MB-435 human breast carcinoma cells that express low levels of NM23-H1. M2 muscarinic receptors and GIRK1/GIRK4 channel subunits were co-expressed in cells stably transfected with vector only (control), wild-type NM23-H1, or several NM23-H1 mutants. Lysates from all cell lines tested exhibit comparable nucleoside diphosphate (NDP) kinase activity. Whole cell patch clamp recordings revealed a substantial reduction of the acute desensitization of muscarinic K+ currents in cells overexpressing NM23-H1. The mutants NM23-H1P96S and NM23-H1S44A resembled wild-type NM23-H1 in their ability to reduce desensitization. In contrast, mutants NM23-H1S120G and NM23-H1S120A completely abolished the effect of NM23-H1 on desensitization of muscarinic K+ currents. Furthermore, NM23-H1S120G potentiated acute desensitization, indicating that this mutant retains the ability to interact with the muscarinic pathway, but has properties antithetical to those of the wild-type protein. We conclude that NM23 acts as a suppressor of the processes leading to the desensitization of muscarinic K+ currents, and that Ser-120 is essential for its actions.

Aldose reductase inhibition prevents galactose-induced ovarian dysfunction in the Sprague-Dawley rat

OBJECTIVE

Our objective was to determine whether impaired ovarian function induced by short-term creation of a galactosemic state in the rat might be prevented by the coadministration of an aldose reductase inhibitor.

STUDY DESIGN

Prepubertal Sprague-Dawley rats were fed four different diets including (1) control, (2) 40% galactose, (3) 40% galactose and an aldose reductase inhibitor, and (4) an aldose reductase inhibitor with the control diet. Percentage germinal vesicle breakdown, postovulatory oocyte quantities, hormonal parameters, ovarian histologic evaluation, and ovarian galactitol concentrations were determined.

RESULTS

The galactose-fed animals (group 2) had decreased germinal vesicle breakdown (47%) versus control (69%, p < 0.05). Galactose-exposed animals had significantly decreased quantities of postovulatory eggs (6.4 per animal) after menotropin ovarian stimulation in comparison with controls (14.1, p < 0.01). In rats exposed to high dietary levels of galactose (group 2) ovarian galactitol concentrations were significantly higher (protein 42.12 mumol/gm versus 0.0 for controls, p < 0.005). When galactose-fed animals received the aldose reductase inhibitor, ovarian accumulation of galactitol was significantly reduced and the observed detrimental effects on the oocyte were prevented.

CONCLUSION

Galactitol accumulation or metabolic flux through aldose reductase in galactosemic rodents may be involved in the demonstrated ovarian dysfunction.

Diagnosis of uterine anomalies: relative accuracy of MR imaging, endovaginal sonography, and hysterosalpingography

The purpose of this study was to compare the relative accuracy of magnetic resonance (MR) imaging (n = 26), endovaginal sonography (EVS) (n = 14), and hysterosalpingography (HSG) (n = 20) in the classification of müllerian duct anomalies in 26 patients. There were 24 cases of surgically proved anomaly, and two patients had normal uteri (one with a vaginal septum). MR imaging allowed diagnosis of 24 of 24 cases (accuracy, 100%), and EVS was correct in 11 of 12 cases (accuracy, 92%). HSG was correct in only four cases. In the diagnosis of septate uterus, MR imaging demonstrated a sensitivity and specificity of 100% and EVS demonstrated a sensitivity of 100% and a specificity of 80%. Both MR imaging and EVS demonstrated a sensitivity and specificity of 100% in distinguishing those anomalies that did not require surgery. The high accuracy of MR imaging and EVS permit noninvasive differentiation of uterine anomalies and can spare women diagnostic laparoscopy, promoting cost-effective diagnosis.

Magnetic resonance imaging in müllerian fusion defects

MRI may replace laparoscopy in the workup of many women with uterine anomalies because of its ability to optimally distinguish the shape of the fundal contour (differentiating septate and bicornuate uteri) as well as to delineate uterine, cervical and vaginal components. Other anomalies, such as unicornuate uterus and uterus didelphis, concealed hemorrhage within noncommunicating horns, müllerian or cervical agenesis, and vaginal septa, are also well defined by MRI. For patients with uterine or vaginal septa, MRI can set the stage for a definitive diagnosis and more informed preoperative patient preparation. Moreover, since many of the other conditions are not amenable to surgery, MRI can mean the avoidance of otherwise purely diagnostic surgery.

Epidemiology and etiology of ectopic pregnancy

Although advances in earlier diagnosis have led to decreased case-fatality rates and conservative laparoscopic treatments have enabled improved outcomes, ectopic pregnancy remains a leading cause of maternal mortality and accounts for a sizable proportion of infertility and ectopic recurrence. The incidence of ectopic pregnancy, the trends observed in the last decade, reason for occurrence, and other questions regarding risk factors for this condition are discussed.

Persistent ectopic pregnancy following laparoscopic linear salpingostomy

As the surgical approach for ectopic pregnancies evolves from radical to conservative procedures, the potential hazard of persistent ectopic pregnancy has become increasingly pertinent. From September 1, 1986 to August 31, 1989, 11 women with persistent ectopic pregnancy after laparoscopic salpingostomy were diagnosed and treated at Yale-New Haven Hospital. Persistent ectopic pregnancy was suspected in nine cases because of symptoms and in two because of plateauing beta-hCG titers. Ten of 11 patients underwent repeat surgery. Eight had partial or complete salpingectomy of the involved ipsilateral tube, two had repeat salpingostomies, and one was treated with methotrexate. When the 11 women with persistent ectopic pregnancies were compared with 70 patients treated successfully by laparoscopic salpingostomy using multivariate stepwise logistic regression, smaller size of the ectopic (P less than .01) and fewer days of amenorrhea (P less than .05) predicted persistent ectopic pregnancy after laparoscopic salpingostomy. Based upon our experience, we believe that earlier-treated ectopic pregnancies (ie, fewer than 42 days of amenorrhea) and/or smaller ectopics (ie, 2.0 cm or less in diameter) require treatment with particular caution and close postoperative surveillance.

Mechanism of relief of pacing induced angina with oral verapamil: reduced oxygen demand

To evaluate the influence of oral verapamil (80 and 120 mg) on angina threshold, coronary blood flow, myocardial oxygen consumption and left ventricular function, we subjected 13 patients with effort angina and fixed obstructive coronary artery disease to atrial pacing at progressively higher heart rates. After 120 mg of verapamil, the time to onset of angina and the heart rate at the onset of ST-segment depression increased by 18% (p less than 0.005) and 10% (p less than 0.001), respectively, without any change in the angina threshold (rate-pressure product at the onset of angina). The rate-pressure product, coronary blood flow and myocardial oxygen consumption were lower at rest and at pre-angina heart rates but not when the angina threshold was reached. Thus, the beneficial effect of verapamil was primarily due to decreased myocardial oxygen demand rather than to increased coronary blood flow. The decreased demand resulted from a lower arterial pressure at each pacing rate. In these patients without heart failure, left ventricular pump function did not deteriorate. This beneficial response was less with 80 mg of oral verapamil. These findings suggest that oral verapamil has a potential role in the management of patients with effort angina due to fixed obstructive coronary artery disease.