EXO1-mediated DNA repair by single-strand annealing is essential for BRCA1-deficient cells.

Deficiency for the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR) leads to chromosomal instability and diseases such as cancer. Yet, defective HR also results in vulnerabilities that can be exploited for targeted therapy. Here, we identify such a vulnerability and show that BRCA1-deficient cells are dependent on the long-range end-resection factor EXO1 for survival. EXO1 loss results in DNA replication-induced lesions decorated by poly(ADP-ribose)-chains. In cells that lack both BRCA1 and EXO1, this is accompanied by unresolved DSBs due to impaired single-strand annealing (SSA), a DSB repair process that requires the activity of both proteins. In contrast, BRCA2-deficient cells have increased SSA, also in the absence of EXO1, and hence are not dependent on EXO1 for survival. In agreement with our mechanistic data, BRCA1-mutated tumours have elevated EXO1 expression and contain more genomic signatures of SSA compared to BRCA1-proficient tumours. Collectively, our data indicate that EXO1 is a promising novel target for treatment of BRCA1-deficient tumours.

Assessment of the Clinical Impact of a Liver-Specific, BCAA-Enriched Diet in Major Liver Surgery.

BACKGROUND: The relationship between nutrition and liver disease is relevant for the outcome after surgery. Patients with liver cirrhosis characteristically show protein-energy malnutrition with decreased levels of branched-chain amino acids (BCAA) and increased levels of aromatic amino acids. MATERIALS AND METHODS: We conducted a prospective controlled clinical trial including 57 patients after liver transplantation or major liver resection surgery in order to test the effect of early postoperative nutrition on the outcome and nutrition profile of these patients. The test group received a dietetic program composed of ingredients naturally rich in BCAA (BCAA group), and the control group received standard hospital meals. Patient survival, liver function tests, subjective well-being, and a nutritional status including amino acid profiles were analyzed immediately and 14 days after major liver surgery (secondary end points). General health and well-being were assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (primary end point). RESULTS: In-depth analysis of amino acid profiles was performed for patients undergoing liver resection (n = 21) and liver transplantation (n = 36). Interestingly, amino acid profiles did not correlate with body mass index or the Model for End-Stage Liver Disease score. Patients scheduled for liver transplantation showed significantly lower levels of BCAA pretransplant compared to patients undergoing liver resection. Patients in the liver resection subgroup were more likely to benefit from the BCAA cuisine in terms of significantly higher food intake and subjective rating. The clinical liver function tests, however, did not show statistical difference between the BCAA group and the control group in the examination period of 14 days. CONCLUSION: Our specifically designed BCAA-enriched diet resulted in greater patient satisfaction and compliance with nutrition. A larger trial or longer-term follow-up may be required to identify an effect on survival, recovery, surgical complications, protein profiles, and amino acid profiles.

Physician pain and discomfort during minimally invasive gynecologic cancer surgery.

OBJECTIVE: Despite increasing awareness of physical strain to surgeons associated with minimally invasive surgery (MIS), its use continues to expand. We sought to gather information from gynecologic oncologists regarding physical discomfort due to MIS. METHODS: Anonymous surveys were e-mailed to 1279 Society of Gynecologic Oncology (SGO) members. Physical symptoms (numbness, pain, stiffness, and fatigue) and surgical and demographic factors were assessed. Univariate and multivariate analyses were performed to determine risk factors for physical symptoms. RESULTS: We analyzed responses of 350 SGO members who completed the survey and currently performed >50% of procedures robotically (n=122), laparoscopically (n=67), or abdominally (n=61). Sixty-one percent of members reported physical symptoms related to MIS. The rate of symptoms was higher in the robotic group (72%) than the laparoscopic (57%) or abdominal groups (49%) (p=0.0052). Stiffness (p=0.0373) and fatigue (p=0.0125) were more common in the robotic group. Female sex (p<0.0001), higher caseload (p=0.0007), and academic practice (p=0.0186) were associated with increased symptoms. On multivariate analysis, robotic surgery (odds ratio [OR] 2.38, 95% CI 1.20-4.69) and female sex (OR 4.20, 95% CI 2.13-8.29) were significant predictors of symptoms. There was no correlation between seeking treatment and surgical modality (laparotomy 11%, robotic 20%, laparoscopy 25%, p=0.12). CONCLUSIONS: Gynecologic oncologists report physical symptoms due to MIS at an alarming rate. Robotic surgery and female sex appear to be risk factors for physical discomfort. As we strive to improve patient outcomes and decrease patient morbidity with MIS, we must also work to improve the ergonomics of MIS for surgeons.

Factors associated with recent HIV testing among men who have sex with men in New York City.

Understanding factors associated with recent HIV testing among men who have sex with men (MSM) is important for designing interventions to increase testing rates and link cases to care. A cross-sectional study of MSM was conducted in NYC in 2011 using venue-based sampling. Associations between HIV testing in the past 12 months and relevant variables were examined through the estimation of prevalence ratios (PR) and 95 % confidence intervals (CI). Of 448 participants, 107 (23.9 %) had not been tested in the past 12 months. Factors independently associated with not testing in the previous 12 months were: lack of a visit to a healthcare provider in the past 12 months (aPR: 2.5; 95 % CI: 1.9, 3.2); age ≥30 (adjusted PR: 1.9; 95 % CI: 1.4, 2.7); not having completed a bachelor's degree (aPR: 1.6; 95 % CI: 1.0, 2.4); and non-gay sexual identity (aPR: 1.4; 95 % CI: 1.0, 1.8); such MSM may be less aware of the need for frequent HIV testing.

Herpes simplex virus type 2 associated with HIV infection among New York heterosexuals living in high-risk areas.

Herpes simplex virus type 2 (HSV-2) has been shown to increase the risk of sexual human immunodeficiency virus (HIV) transmission. A matched case-control design was used to examine the association between HSV-2 and HIV infection among heterosexuals in 'high-risk areas' (HRAs) in New York City (NYC). We identified NYC HRAs using HIV surveillance data on heterosexual-related adult HIV diagnoses and USA census data on household poverty. Heterosexuals who were socially or geographically linked to an HRA were recruited using respondent-driven sampling. HIV prevalence was 8.6% and HSV-2 prevalence was 80.1%. Only 6% of HIV-positives knew they were infected. HIV-positive cases were matched to HIV-negative controls on gender, race/ethnicity and age, and tested for antibody to HSV-2. In a multivariate model, HIV infection was associated with HSV-2 infection (adjusted odds ratio [AOR] = 3.5, 95% confidence interval 1.1-11.7) and non-HSV-related sexually transmitted infection diagnosis in the previous year (AOR = 2.6, 1.1-6.2). Effective approaches to HIV risk reduction for individuals with HSV-2 remain uncertain, and these are urgently needed in high-risk communities where multiple social, behavioural and biological factors that facilitate HIV infection coexist.

Immunoengineering: a credible mechanism for CAMPATH-1H action in bone marrow and organ transplantation and the implications for treatment of the immune dysfunction AIDS.

Immunoengineering is a term coined to represent the mostly future ability to use or target the immune system's natural components, with emphasis on the regulatory components, to up or down regulate the immune system's attack against specific proteins associated with an unwanted pathology or immune occurrence. It will constitute manipulating parts of the immune system, mostly those specific for the disease associated antigen(s) and generally of a regulatory nature, in various immunological locale or the whole body compartment, to achieve a disease free state for the patient. The number of practical applications awaiting the mastery of immune components as regulatory therapeutics is enormous and immunoengineering should provide treatments in a wide range of disease categories. HIV is a disease where this discipline could provide a quick cure, even eradication of the virus. A potential cheap solution to HIV infection, based on using immunoengineering and adaptable to the infrastructure problems of the Third World is highlighted in the following because of the health emergency that exists in the Third World.

An editorial for the HIV infected: immune regulation. The implications for treatment of HIV infection and the potential role of T cell suppressor pathways instead of apopstasis, anergy or direct CD4 T cell deletion in AIDS pathogenesis.

The AIDS crises makes for an interesting study of the interactions of activists, researchers, caregivers, the press, politicians and other groups in society. In the popular press and elsewhere there has been a growing movement since the inception of the disease to place efforts against AIDS as the highest standard of our benevolence, proficiency and determination when confronting a disease. Because of the potential benefit in understanding the interactions of groups and how research progressed and failed during the AIDS crises, differing perspectives should be recorded on this matter. The person currently in most need of an objective viewpoint on AIDS research, including an outlook on the past, as well as the present and future, is the person who is infected with HIV. While many of the AIDS related bureaucracies, scientists and celebrities have achieved consecration in the fight against HIV, a question arises whether this praise is deserved and really due to their keeping the AIDS patient as the first matter of the heart and mind; or whether they have merely achieved what bureaucracies and celebrity are best at, making society and those they should serve, think that they cannot do with out them.The following editorial chronicles a scandalous intellectual failure of immunologists in the fight against HIV. It delineates potential areas of concern for the HIV infected patient in the present and future, which may be important directions in the fight against HIV, both for treatment to evolve to the ideal and for an economically viable treatment for the Third World.

The beneficial effect of donor-specific transfusions: a review of existing explanations and a new hypothesis based on a relatively unapplied theory of T cell immunoregulation. A regulatory hypothesis in progress...

The mechanism by which donor specific transfusions protect a graft from the recipient's immune system is unknown. It is likely that this beneficial mechanism is a subset or distinct exhibition of the general rules governing the regulation of the immune system. This phenomenon provides a strong framework for investigation of immune regulation, considering its potential consanguinity to immune regulation, that it is a paradox representing a manifestation of regulatory rules, and that it provides a wealth of clinical experience and experimentation from which to make inferences. Vital in any exploration of immune regulation, is the promise held in reducing the immune system to its chief elemental regulatory mechanisms and interactions. Strangely, the majority of this consequential work may have already been accomplished by Gershon, Green and colleagues with their elegant demarcation of T cell regulation into suppressor and contrasuppressor pathways. The practical and theoretical implications of this discovery seem to be, for the most part, ignored by mainstream immunology. It is doubtful, based on the quality and quantity of their work, or confirming work by other laboratories that they were inaccurate in their findings. It remains a horrible waste that their discoveries are not in immunology's pantheon of hallowed discoveries and are little used. With all this kept in mind, a comprehensive hypothesis of regulation was put together based mainly on Gershon's portrait of the suppressor and contrasuppressor pathways' contributions to immune regulation and experimentation surrounding the unsolved paradox of donor specific transfusions.

Effect of acute hypercapnia on diaphragmatic and limb muscle contractility.

The purpose of this study was to determine whether acute hypercapnia depresses limb muscle and diaphragmatic contractility. Twelve subjects breathed 8% CO2 for 20 min on two separate occasions. On one occasion, twitch transdiaphragmatic pressure (Pdi) was obtained during both cervical magnetic and transcutaneous stimulation before and 2, 10, and 30 min after CO2 breathing. In addition, twitch Pdi was obtained during CO2 breathing in five subjects using cervical magnetic stimulation. On the other occasion, adductor pollicis twitch force was measured during transcutaneous supramaximal ulnar nerve stimulation and arterialized venous blood gas determinations were obtained before, during, and after CO2 breathing. Twitch Pdi was not significantly different from baseline at any time after CO2 breathing. Similarly, twitch Pdi did not significantly change from the beginning to the end of the period of CO2 breathing. In contrast, adductor pollicis twitch force was significantly less than baseline 2 min after CO2 breathing (p < 0.01). Furthermore, during CO2 breathing, adductor pollicis twitch force fell significantly, reaching statistical significance at 8 min, decreasing still further by 13 min, and then plateauing. During the final 2 min of CO2 breathing, adductor pollicis twitch force averaged 86.5 +/- 2.7% of the baseline value (p < 0.0007). During CO2 breathing, Pco2 rose to 60.1 +/- 0.5 mm Hg, whereas pH fell to 7.27 +/- 0.004 units. Breathing 8% CO2 elicited a moderate hyperpnea, and minute ventilation during the final minute of CO2 breathing averaged 54.74 +/- 4.90 L/min. To ensure that this hyperpnea did not augment diaphragmatic activity enough to potentiate the twitch, five subjects voluntarily mimicked their CO2 hyperpnea on a separate occasion. Twitch Pdi was not significantly different from baseline at any time after voluntary mimicking. To ensure that changes in diaphragmatic contractility were not missed by our twitch measurements, Pdi was measured during bilateral transcutaneous phrenic nerve stimulation at 10 Hz in four subjects. Again, Pdi during 10 Hz stimulation was not significantly different from baseline at any time after CO2 breathing. In conclusion, (1) acute moderate hypercapnia mildly depresses limb muscle contractility, and (2) acute moderate hypercapnia did not produce significant changes in diaphragmatic contractility.

Heated lymphocytes express HLA-DR antigens despite their inability to stimulate in MLC.

We have utilized serological techniques and mixed lymphocyte culture (MLC) reactions to examine HLA-DR and HLA-D expression by heated (45 degrees C for 1 h) lymphocytes in order to study the functional relationship of these antigens. Heated lymphocytes do not stimulate proliferation of allogeneic lymphocytes in MLC, yet they express HLA-DR antigens. The fraction of peripheral blood lymphocytes (PBL) expressing DR is not altered by heating, nor is the staining intensity altered as detected by fluorescence microscopy. Alloantisera to "B cell alloantigens" recognize HLA-DR determinants on heated cells without any detectable change in either specificity or quantitative cytotoxic effects. Flow cytometry with monoclonal antibody demonstrates only minimal decrease in HLA-DR expression after heating. Thus stimulation in MLC requires more of the stimulating cell than the mere expression of HLA-DR.

HLA identical leukemia cells and T cell growth factor activate cytotoxic T cell recognition of minor locus histocompatibility antigens in vitro.

Lymphocytes from a healthy HLA-identical bone marrow transplant donor were tested for their ability to destroy her brother's acute myelogenous leukemia blasts in vitro. Primary mixed lymphocyte culture (MLC) and cell-mediated lysis (CML) responses between the patient's remission (pretransplant) and donor's lymphocytes were negative. Stimulation of donor lymphocytes for 7 d in vitro with irradiated leukemia cells, leukemia cells plus allogeneic irradiated lymphocytes, or a pool of irradiated lymphocytes from 10 donors, did not activate any cytotoxic cells able to destroy the HLA identical leukemic blasts. Further culturing for 7 additional d in T cell growth factor (TCGF) generated lymphocytes that induced effective cytotoxicity against the leukemic blasts, but not against autologous lymphocytes. Effective killing against the leukemia was observed only in cultures initially stimulated with the irradiated leukemia cells. These cytotoxic cells were maintained in TCGF and mediated persistent killing against the leukemic target cells. They were also able to destroy lymphocytes from the patient's mother and father, but not from an unrelated cell donor. This suggested specific recognition of non-HLA antigens inherited by the patient, that were foreign to the HLA identical bone marrow donor. These lymphocytes were cloned by a limiting dilution technique and one clone maintained cytotoxicity to the AML blasts and the father's lymphocytes, but not lymphocytes from the mother or an HLA-identical donor. This cytotoxicity was inhibited by a monoclonal anti-HLA antibody. Thus, in vitro sensitization of this sibling's lymphocytes with AML blasts followed by TCGF expansion, and cloning, enabled the detection of HLA-restricted cytotoxic cells that recognize minor locus histocompatibility antigens. This immune recognition may be relevant to the "graft vs. leukemia" effect that has been observed in leukemic animals and patients following histocompatible hematopoietic transplants.

Hemodynamics, hypoglycemia, and hepato-pancreatic pathology during the course of endotoxin shock.

The interrelationships between hemodynamics and hypoglycemia during the course of endotoxin shock (ES) has not been fully defined. In the following study, ES (E. coli, 1 mg/kg; n = 7) was induced in a canine model and systemic hemodynamics, glucose metabolism, and hepatic and pancreatic function monitored for 5 hr and compared to time-matched controls (TMC, n = 7). Total peripheral resistance (TPR, dynes-sec-cm-5) increased from 3227 +/- 430 to 4050 +/- 750 at 30 min and then declined to 3050 +/- 1100 at 90 minutes. TPR progressively increased to 6225 +/- 749 by 5 hours. Plasma glucose did not significantly differ from control values (105 +/- 4 mg%) for the first 90 min but then declined to 68 +/- 6 mg% at 4.5 hours. (TMC = 103 +/- 17, P less than 0.05). Serum amylase during the 5 hr protocol was not elevated (TMC = 110.9 +/- 2.4; ES = 100 +/- 1.97%; P greater than 0.1), and light microscopy of the exocrine pancreas demonstrated normal acinar structure. Islet cell structure from the ES group is not significantly different from the TMC. Hepatic histology in the ES group demonstrated periportal and perilobular degranulation and hepatocyte disruption not seen in the TMC. It is hypothesized that ES results in a circle of positive feedback initiated by an increase in TPR and subsequent decrease in flow resulting in hepato-pancreatic ischemia. Ischemic damage is most apparent at the liver and leads to changes in hepatic metabolic activities which contribute to the developing hypoglycemia of the late phase of ES.