Examining HIV Stigma, Depression, Stress, and Recent Stimulant Use in a Sample of Sexual Minority Men Living with HIV: An Application of the Stigma and Substance Use Process Model.

Sexual minority men (SMM) with HIV are disproportionately impacted by stigma and mental health disorders. Guided by the Stigma and Substance Use Process Model, we evaluated how HIV stigma impacts mental health outcomes among SMM with HIV. Data were drawn from Thrive With Me, an RCT of an mHealth intervention targeting ART adherence among SMM with HIV. Path analyses tested the relationships between HIV stigma, depression, stress, and recent stimulant use. Overall, 49.1% (194/401) had depression symptoms, 68.8% (276/401) had moderate-to-high stress, and 28.1% (111/401) had detectable stimulant use in urine samples at baseline. In path analyses, baseline internalized HIV stigma was associated with depression and stress 5-months post-baseline and enacted stigma was associated with recent stimulant use 11-months post-baseline. We identified internalized and enacted HIV stigma, but not anticipated stigma, as potentially important intervention targets for stimulant use, depression, and stress among SMM with HIV.

Evaluation of the novel artus C. difficile QS-RGQ, VanR QS-RGQ and MRSA/SA QS-RGQ assays for the laboratory diagnosis of Clostridium difficile infection (CDI), and for vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) screening.

Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are worldwide prevalent healthcare-associated pathogens. We have evaluated three Qiagen artus QS-RGQ assays for the detection of these pathogens. We examined 200 stool samples previously tested for C. difficile infection (CDI), 94 rectal swabs previously screened for VRE and 200 MRSA screening nasal swabs. With the routine diagnostic laboratory results being adopted as the gold standard, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the artus C. difficile assay were 100%, for the artus VanR QS-RGQ assay, 95, 68, 44 and 98%, and for the artus MRSA/SA assay, 80, 94, 93 and 83%, respectively. The artus VanR assay detected the vanA and/or vanB genes in 32% of culture-negative VRE screens; in 71% of these cases, only vanB was detected. An over-estimation of the rate of faecal VRE colonisation could be due to a patient population with high rates of faecal carriage of non-enterococcal species carrying vanB. Based on our findings, we conclude that all three artus QS-RGQ assays could be a useful addition to a diagnostic laboratory, and that the optimal choice of assay should be determined according to user needs.

Stem cell-based strategies and challenges for production of cultivated meat.

Cultivated meat scale-up and industrial production will require multiple stable cell lines from different species to recreate the organoleptic and nutritional properties of meat from livestock. In this Review, we explore the potential of stem cells to create the major cellular components of cultivated meat. By using developments in the fields of tissue engineering and biomedicine, we explore the advantages and disadvantages of strategies involving primary adult and pluripotent stem cells for generating cell sources that can be grown at scale. These myogenic, adipogenic or extracellular matrix-producing adult stem cells as well as embryonic or inducible pluripotent stem cells are discussed for their proliferative and differentiation capacity, necessary for cultivated meat. We examine the challenges for industrial scale-up, including differentiation and culture protocols, as well as genetic modification options for stem cell immortalization and controlled differentiation. Finally, we discuss stem cell-related safety and regulatory challenges for bringing cultivated meat to the marketplace.

Jaundice and a testicular lump: a rare cause of malignant biliary obstruction.

Biliary obstruction from metastatic deposits in the pancreas is rare. We present a case of primary testicular lymphoma (PTL) with pancreatic metastasis. A 56-year-old man presented to the general surgical department with signs and symptoms of obstructive jaundice. A computed tomography scan revealed multiple pancreatic metastases and a right primary testicular malignancy. Histology and positron emission tomography scanning subsequently confirmed PTL with pancreatic metastases. Metastasis to the pancreas from primary testicular malignancy is extremely rare. There is variation in prognosis between primary and secondary pancreatic malignancies and therefore in atypical cases of malignant biliary obstruction consideration must be given to the rarer secondary malignancies.

The intersection of gender and drug use-related stigma: A mixed methods systematic review and synthesis of the literature.

BACKGROUND: Substance use-related stigma is a significant barrier to care among persons who use drugs (PWUD). Less is known regarding how intersectional identities, like gender, shape experiences of substance use-related stigma. We sought to answer the following question: Do men or women PWUD experience more drug use stigma? METHODS: Data were drawn from a systematic review of the global, peer-reviewed scientific literature on substance use-related stigma conducted through 2017 and guided by the Stigma and Substance Use Process Model and PRISMA guidelines. Articles were included in the present analysis if they either qualitatively illustrated themes related to the gendered nature of drug use-related stigma, or quantitatively tested the moderating effect of gender on drug use-related stigma. RESULTS: Of the 75 studies included, 40 (53 %) were quantitative and 35 (47 %) were qualitative. Of the quantitative articles, 22 (55 %) found no association between gender and drug use-related stigma, 4 (10 %) identified women who use drugs (WWUD) were more stigmatized, and 2 (5 %) determined men who use drugs (MWUD) were more stigmatized. In contrast, nearly all (34; 97 %) of the qualitative articles demonstrated WWUD experienced greater levels of drug use-related stigma. CONCLUSION: The quantitative literature is equivocal regarding the influence of gender on drug use-related stigma, but the qualitative literature more clearly demonstrates WWUD experience greater levels of stigma. The use of validated drug use-related stigma measures and the tailoring of stigma scales to WWUD are needed to understand the role of stigma in heightening the disproportionate harms experienced by WWUD.

"I wanted to close the chapter completely and I feel like that [carrying naloxone] would keep it open a little bit": Refusal to carry naloxone among newly-abstinent opioid users and 12-step identity.

BACKGROUND: 12-step programs aim to address drug-related harms, like opioid overdose, via abstinence. However, abstaining from opioids can diminish tolerance, which increases risk for overdose death upon resumption. A recent study found that desire to abstain from drugs inhibited willingness to participate in take-home naloxone programming, which was linked to perceptions of harm reduction strategies being tied to drug use. In the present study, we uncovered a similar phenomenon occurring among newly-abstinent participants who were refusing to carry naloxone. METHODS: This study is an analysis of broader qualitative data collected throughout Southern California among persons who use opioids, including those recently abstinent. Preliminary analysis revealed that those newly abstinent refused to accept naloxone at the end of interviews, and so we began probing about this (N=44). We used thematic analysis and author positionality to explicate the emergent phenomenon and applied social identity theory to conceptualize findings. RESULTS: Mechanisms underlying naloxone refusal included its tie to a drug-using identity that newly-abstinent participants were attempting to retire. Carrying naloxone was also viewed as pointless due to doubt of witnessing an overdose again. Furthermore, the thought of being equipped with naloxone was not believed to be congruent with an abstinent identity, e.g. "me carrying it [naloxone] is making me feel like I'm going to be hanging out with people that are doing it [using drugs]." CONCLUSION: Recent detoxification heightens vulnerability to overdose, which other newly-abstinent peers might be positioned to respond to as bonds are formed through 12-step identity formation. However, naloxone is often refused by this group due to perceived 12-step identity clash. While some treatment spaces distribute naloxone, 12-step identity associated behavioral expectations appear to conflict with this strategy. Reframing these disconnects is essential for expanding the lifesaving naloxone community safety net.

"Generally, you get 86'ed because you're a liability": An application of Integrated Threat Theory to frequently witnessed overdoses and social distancing responses.

While rates of opioid overdose deaths in North American have increased exponentially in recent years, most overdoses are not fatal, especially when witnesses are present and can intervene. Previous research has found that some people who use drugs [PWUDs] trained in overdose response might cut social ties with frequent overdosers, leading to more solitary opioid use and risk of death if someone overdoses alone. To examine the phenomenon of social distancing of people who overdose frequently, we used data from fifty-two in-depth qualitative interviews collected in Southern California with PWUDs who had recently witnessed an opioid overdose. Transcripts were reviewed and coded thematically, using the Integrated Threat Theory (ITT) to conceptualize the observed phenomenon. ITT outlines how realistic and symbolic threats are experienced by a group. We found that while some participants acknowledged the role of adulterated street drugs in overdoses, individualized blame was nonetheless imposed. Accusations of careless drug use practices fostered negative stereotyping towards frequent overdosers. This was attributed to the need to summon 911 for rescue, which often resulted in police dispatch. The intergroup relationship between police and PWUDs is precarious as police pose realistic threats onto PWUDs - such as incarceration, eviction, and manslaughter charges - leading to intragroup anxiety among PWUDs about future overdose events, and labelled frequent overdosers as liabilities. These threats, and inter/intra-group conflict, explained one reason how and why non-fatal overdoses led to social distancing events. People who overdose frequently were also accused of breaking the norm of drug user surreptitiousness; a symbolic threat that endangered the group due to police exposure. Social distancing might dampen exposure to the protective effect of peer-led interventions such as take-home naloxone programs, increasing risk of overdose death. This phenomenon highlights how intergroup dynamics are driving intragroup processes. Suggestions for tailoring public health interventions are discussed.

Homologies between T cell receptor junctional sequences unique to multiple sclerosis and T cells mediating experimental allergic encephalomyelitis.

The selection of T cell clones with mutations in the hypoxanthine guanine phosphoribosyltransferase (hprt) gene has been used to isolate T cells reactive to myelin basic protein (MBP) in patients with multiple sclerosis (MS). These T cell clones are activated in vivo, and are not found in healthy individuals. The third complementarity determining regions (CDR3) of the T cell receptor (TCR) alpha and beta chains are the putative contact sites for peptide fragments of MBP bound in the groove of the HLA molecule. The TCR V gene usage and CDR3s of these MBP-reactive hprt-T cell clones are homologous to TCRs from other T cells relevant to MS, including T cells causing experimental allergic encephalomyelitis (EAE) and T cells found in brain lesions and in the cerebrospinal fluid (CSF) of MS patients. In vivo activated MBP-reactive T cells in MS patients may be critical in the pathogenesis of MS.

Eradication of established tumors by vaccination with Venezuelan equine encephalitis virus replicon particles delivering human papillomavirus 16 E7 RNA.

The etiological role of human papillomaviruses (HPV) in cervical and other cancers suggests that therapeutic vaccines directed against requisite viral antigens may eradicate tumors or their precursors. A Venezuelan equine encephalitis (VEE) alphavirus vector delivering the HPV16 E7 RNA was evaluated for antitumor efficacy using a murine E7+ tumor model. Vaccination with VEE replicon particles expressing E7 (E7-VRP) induced class I-restricted CD8+ T-cell responses as determined by IFN-gamma enzyme-linked immunospot (ELISPOT), tetramer, and cytotoxicity assays. E7-VRP vaccination prevented tumor development in all of the mice and effectively eliminated 7-day established tumors in 67% of tumor-bearing mice. The induction of protective T-cell responses was dependent on CD8+, but not CD4+ T cells. Long-lasting T-cell memory responses developed in E7-VRP-vaccinated mice as determined by complete protection from tumor challenge 3 months after the final vaccination. These promising results highlight the potent CD8+ T-cell-mediated antitumor effects elicited by VEE replicon-based vectors and support their further development toward clinical testing against cervical intraepithelial neoplasia or carcinoma.

Tamoxifen rechallenge: response to tamoxifen following relapse after adjuvant chemohormonal therapy for breast cancer.

Two-hundred seventy-three node-positive primary breast cancer patients with positive estrogen or progesterone receptors were placed on a short-term chemohormonal adjuvant program that included tamoxifen. At present, 64 have relapsed, 19 of whom have been rechallenged with tamoxifen after disease-free intervals (DFI) ranging from 0.4 to 4.4 years. Most patients had only one site of disease recurrence. Two patients have achieved complete remission (CR) and three partial remission (PR) for a CR and PR rate of 26% (95% confidence interval for CR and PR is 9% to 51%). Duration of response has ranged from 3 to 17+ months. Patients who receive short-term adjuvant therapy with tamoxifen and who relapse may respond to tamoxifen rechallenge. In this series, the response rate to tamoxifen rechallenge was similar to the response rate for patients unselected for estrogen receptor status receiving first-line endocrine therapy for breast cancer relapse.

Is esmolol cardioprotective? Tolerance of pacing tachycardia, acute afterloading and hemodilution in dogs with coronary stenosis.

OBJECTIVES: The aim of this study was to determine whether esmolol, an ultrashort-acting beta-adrenergic antagonist, possesses cardioprotective properties unrelated to a concomitant decrease in heart rate. BACKGROUND: Previous studies have demonstrated beneficial effects of beta-adrenergic blocking agents with unchanged heart rates. METHODS: The effect of esmolol (100 micrograms/kg per min) on the response of global cardiovascular and regional myocardial contractile function (sonomicrometry) to pacing-induced tachycardia and acute left ventricular afterloading was assessed in dogs with a critical stenosis of the left anterior descending coronary artery (LAD). These responses were observed at the baseline hemoglobin level (12.5 +/- 0.3 g/100 ml) as well as after hemodilution-induced mild regional contractile dysfunction (7.4 +/- 0.4 g/100 ml) in the area supplied by this artery (LAD area). Data were analyzed by using a repeated measures multivariate analysis of variance with complete block design treating pacing rate and afterloading, respectively, as the repeated measure. RESULTS: Esmolol decreased the maximal first derivative of left ventricular pressure (dP/dtmax); global cardiovascular and regional myocardial contractile function were otherwise unchanged. Esmolol did not alter the response of global cardiovascular or regional myocardial function to pacing-induced tachycardia or to acute left ventricular afterloading, both at the baseline hemoglobin level as well as during mild hemodilution-induced LAD area contractile dysfunction. CONCLUSIONS: At an infusion rate of 100 micrograms/kg per min we were unable to demonstrate cardioprotective esmolol effects in a canine model of critical coronary stenosis with controlled heart rate and identical loading conditions.

Validation of 133Xe clearance as a cerebral blood flow measurement technique during cardiopulmonary bypass.

133Xe clearance to measure cerebral blood flow (CBF) was examined in 10 dogs during cardiopulmonary bypass. As a reference method, a continuous Kety-Schmidt technique (CBFKS) with 133Xe as indicator was used. Extracranial tissue was removed to directly place the 133Xe detectors on the skull, and the head was covered with a 3 mm lead shield to minimize contamination of the 133Xe clearance curve with extracranial radiation. 133Xe detectors for the Kety-Schmidt technique were embedded in a shielded brass block to minimize interference with radiation from the animal's body. 133Xe clearance data were analyzed using stochastic (CBF10, CBF15, and CBFINF) and initial slope methods (CBFIS), and the results were compared with CBFKS using linear regression. CBF15 and CBFINF yielded similar CBF values as CBFKS (CBFKS = 0.97.CBF15-2.08, r = 0.92, p less than 0.01; CBFKS = 1.13.CBFINF-1.21, r = 0.92, p less than 0.01). CBF10 slightly overestimated CBFKS but still showed a close correlation to CBFKS (CBFKS = 0.89.CBF10-2.58, r = 0.92, p less than 0.01) and CBFIS considerably overestimated CBFKS (CBFKS = 0.60.CBFIS-1.27, r = 0.87, p less than 0.01). With extracranial contamination of the 133Xe clearance curve minimized, all 133Xe clearance techniques used to measure CBF were consistently related to CBFKS in a constant, significant manner. 133Xe clearance therefore is a valid method to assess CBF during cardiopulmonary bypass.

Lofexidine and clonidine in moderate essential hypertension.

The efficacy, safety, and tolerability of lofexidine, a centrally acting imidazoline derivative, were compared to that of clonidine in a randomized double-blind trial in 28 patients with moderate essential hypertension. The study consisted of a washout phase, a placebo phase, a drug titration phase (0.2 to 1.6 mg/day, with hydrochlorothiazide added at 0.4 mg daily for supine and erect diastolic blood pressure above 90 mm Hg), and a maintenance phase lasting 3 mo. During the titration phase supine systolic and diastolic pressures fell in lofexidine patients from 143 +/- 4/98 +/- 3 to 122 +/- 3/81 +/- 2 mm Hg and in clonidine patients from 154 +/- 6/101 +/- 2 to 124 +/- 4/81 +/- 2 mm Hg (P less than 0.01), and erect systolic and diastolic pressures fell in lofexidine patients from 143 +/- 3/105 +/- 2 to 116 +/- 3/85 +/- 2 mm Hg and in clonidine patients from 156 +/- 6/104 +/- 2 to 117 +/- 4/82 +/- 2 mm Hg (P less than 0.01). Maximal doses of lofexidine and clonidine in combination with hydrochlorothiazide had equivalent antihypertensive effects, but when the effects of lofexidine and clonidine were compared at each dose level, larger doses of lofexidine patients in either the supine or erect position during the titration phase but heart rate fell in the clonidine patients (P less than 0.05) over the same period. Dry mouth and drowsiness were reported in both groups but were both less frequent and less severe in the lofexidine group than the clonidine group.

Interleukin-2 induction of ACTH secretion: presence of an interleukin-2 receptor alpha-chain-like molecule on pituitary cells.

Pituitary cells were shown to release corticotropin (ACTH) in response to interleukin-2 (IL-2) and to express a protein that is related to the alpha-chain of the IL-2 receptor (IL-2R). The alpha-chain-like molecule was bound by a rat monoclonal antibody to the murine IL-2 receptor as well as to IL-2. Sodium dodecylsulfate-polyacrylamide gel electrophoretic analysis of the affinity-purified material from pituitary cells demonstrated a protein which was similar to that which was isolated from activated splenocytes. Thus, IL-2 and its receptor may be one of several hormone-receptor pairs utilized by both the immune and neuroendocrine systems for intersystem communication.

Comparison of bicycle and treadmill radionuclide angiocardiography.

The purpose of this study was to test motion-correction algorithms for initial-transit radionuclide angiocardiograms acquired at rest and during bicycle and treadmill exercise. Treadmill data was spatially reoriented by computer software designed to eliminate motion of a 125I point source simultaneously recorded at a lower energy window. A second algorithm based on left ventricular centroid counts further corrected for motion on all studies. Exercise left ventricular ejection fraction was higher on the treadmill (0.68 +/- 0.07) compared to the bicycle (0.64 +/- 0.08) (p less than 0.0001, r = 0.88). Treadmill exercise also resulted in larger end-diastolic volumes (180 +/- 30 versus 157 +/- 36, p less than 0.0001), stroke volumes (124 +/- 28 versus 101 +/- 29, p less than 0.0001) and cardiac outputs (19.9 +/- 4.6 versus 15.9 +/- 5.0, p less than 0.0001). Similar variances for these hemodynamic measurements suggest that the mean differences observed were physiologic and that error from body motion was effectively corrected by this approach. We conclude that the measurement of left ventricular function during treadmill exercise, when combined with these techniques for correcting motion, is a reasonable alternative to conventional bicycle exercise.

Pathogenesis of paroxysmal hypertension developing during and after coronary bypass surgery: a study of hemodynamic and humoral factors.

A prospective study of hypertension first appearing during and after saphenous vein bypass coronary surgery was performed in 28 patients to examine the incidence, hemodynamics and mechanism of this problem. In 15 patients (54 percent) new hypertension developed (mean arterial pressure greater than 107 mm Hg), characterized by increased peripheral vascular resistance and unchanged cardiac output within 1 hour after surgery. These 15 patients had a longer history of angina of greater severity, but also had relatively well preserved ventricular myocardium. Because plasma renin activity was depressed in patients in the hypertensive group, activation of the renin-angiotensin system was not important in the pathogenesis of this postoperative hypertension. The expected decrease in total peripheral resistance at the onset of cardiopulmonary bypass was observed in all patients, but later during bypass the peripheral resistance increased in all patients in association with a rise in plasma epinephrine levels. Patients who had hypertension postoperatively had a greater increase in arterial pressure and total peripheral resistance during cardiopulmonary bypass than did those with normal postoperative blood pressure. An elevation in plasma epinephrine and norepinephrine concentration, suggesting enhanced sympathoadrenal responsiveness to the challenge of cardiopulmonary bypass, was characteristic of the hypertensive group. This evidence of enhanced sympathetic activity during surgery may be a useful predictor of the development of postoperative hypertension.

Elevated catecholamines during cardiac surgery: consequences of reperfusion of the postarrested heart.

This study determines whether reperfusion of the heart with elevated blood levels of epinephrine (E) and norepinephrine (NE) during cardiac surgery produces deleterious effects. The study was conducted in 60 patients undergoing coronary artery bypass surgery. Arterial catecholamine values increased significantly (p less than 0.05), from prebypass control levels of 152 +/- 29 and 327 +/- 30 pg/ml of E and NE, respectively, to 415 +/- 78 and 554 +/- 49 pg/ml, at initiation of perfusion of the heart after the aortic cross-clamp was removed. Serial measurement of arterial (A) and coronary sinus (CS) E, NE, potassium, lactate, PO2 and CK-MB revealed that during 10 minutes of reperfusion the heart extracted E (positive A-CS difference, p less than 0.05), but that the NE A-CS difference was 0. The CS effluent contained significantly (p less than 0.05) higher concentrations of potassium, lactate and CK-MB during reperfusion than before aortic occlusion. There was no significant correlation of arterial E and NE, CS E and NE or A-CS differences in E and NE with myocardial release of lactate, potassium or CK-MB. There was a weak association (r = 0.4, p less than 0.01) between coronary sinus CK-MB and aortic occlusion time. Maximal arterial E and NE values did not correlate with 10-hour postoperative (maximal) CK-MB values. These results indicate that reperfusion of the postarrested ischemic heart with high levels of endogenously released catecholamines does not worsen ischemia or contribute significantly to myocardial damage.

Performance status and outcome after coronary artery bypass grafting in persons aged 80 to 93 years.

Although coronary artery bypass grafting (CABG) effectively eliminates or diminishes symptoms of myocardial ischemia, the overall performance status and functional outcome in elderly patients undergoing CABG is poorly documented. Therefore, 86 consecutive patients aged 80 to 93 years undergoing isolated CABG were reviewed. Preoperative, intraoperative, and postoperative characteristics and pre- and postoperative performance status (Karnofsky score) were examined. Forty patients (47%) were women, and most patients had highly symptomatic coronary artery disease with class III or IV angina in 94% and unstable angina in 90%. Significant co-morbid disease was present in 49% of patients, and cardiac catheterization revealed left main or 3-vessel disease in 74% of patients. The rate of significant in-hospital complications was 29%, with infection in 14%, stroke in 9%, and respiratory failure in 8% being most frequent. Median performance status (Karnofsky score) improved from 20 to 70% (p = 0.0001) with 89% of hospital survivors being discharged home. Factors associated with failure to achieve a successful functional outcome at discharge were presence of 1 or more preoperative co-morbid conditions (p = 0.048), preoperative myocardial infarction within 7 days of operation (p less than 0.01), and postoperative low cardiac output (p less than 0.01). Survival at 30 days, 6 months, and 3 years were 90, 78, and 64%, respectively. These data demonstrate that CABG can be offered to selected elderly patients with acceptable morbidity and mortality, marked improvement in performance status, and an acceptable quality of life.

Heparin and infarct coronary artery patency after streptokinase in acute myocardial infarction.

Anticoagulant therapy is frequently used after thrombolytic agents in the treatment of acute myocardial infarction (AMI) although it is unclear that such therapy will prevent subsequent infarct vessel reocclusion. The role of duration of heparin therapy in maintaining infarct artery patency was studied retrospectively in 53 consecutive AMI patients who received streptokinase therapy and underwent coronary angiography acutely and at 14 +/- 1 days. Of the 39 patients with initial infarct vessel patency, patency at follow-up angiography was observed in 100% (22 of 22) of those who received greater than or equal to 4 days of intravenous heparin but in only 59% (10 of 17) of those patients who received less than 4 days of heparin (p less than 0.05). Of the 14 patients not initially recanalized after streptokinase, patent infarct-related arteries at follow-up angiography were found in 3 of 8 (38%) treated with greater than or equal to 4 days of heparin therapy but in none of the 6 patients treated for less than 4 days (difference not significant). No significant difference in hemorrhagic complications was noted between the short- and long-term heparin treatment groups. Thus, greater than or equal to 4 days of intravenous heparin therapy after successful streptokinase therapy in AMI is more effective in maintaining short-term infarct vessel patency than a shorter duration of therapy and it may maintain the short-term patency of the infarct vessel in those patients who later spontaneously recanalize.

Comparison of analytic models for estimating the effect of clinical factors on the cost of coronary artery bypass graft surgery.

The cost of treating disease depends on patient characteristics, but standard tools for analyzing the clinical predictors of cost have deficiencies. To explore whether survival analysis techniques might overcome some of these deficiencies in the analysis of cost data, we compared ordinary least square (OLS) linear regression (with and without transformation of the data) and binary logistic regression with two survival models: the Cox proportional hazards model and a parametric model assuming a Weibull distribution. Each model was applied to data from 155 patients undergoing coronary artery bypass grafting. We examined the effects of age, sex, ejection fraction, unstable angina, and number of diseased vessels on univariable and multivariable predictions of costs. The significant univariable predictors of cost were consistent in all models: ejection fraction was significant in all five models, and age and number of diseased vessels were each significant in all but the OLS model, while sex and angina type were significant in none of the models. The significant multivariable predictors of cost, however, differed according to model: ejection fraction was a significant multivariable predictor of cost in all five models, age was significant in three models, and number of diseased vessels was significant in one model. All five models were also used to predict the costs for an average patient undergoing surgery. The Cox model provided the most accurate predictions of mean cost, median cost, and the proportion of patients with high cost. This study shows: (1) lower ejection fraction and older age are independent clinical predictors of increased cost of CABG, and (2) the Cox proportional hazards model shows considerable promise for the analysis of the impact of clinical factors upon cost.