Low-dose 2-deoxy glucose stabilises tolerogenic dendritic cells and generates potent in vivo immunosuppressive effects.

Cell therapies for autoimmune diseases using tolerogenic dendritic cells (tolDC) have been promisingly explored. A major stumbling block has been generating stable tolDC, with low risk of converting to mature immunogenic DC (mDC), exacerbating disease. mDC induction involves a metabolic shift to lactate production from oxidative phosphorylation (OXPHOS) and ß-oxidation, the homeostatic energy source for resting DC. Inhibition of glycolysis through the administration of 2-deoxy glucose (2-DG) has been shown to prevent autoimmune disease experimentally but is not clinically feasible. We show here that treatment of mouse bone marrow-derived tolDC ex vivo with low-dose 2-DG (2.5 mM) (2-DGtolDC) induces a stable tolerogenic phenotype demonstrated by their failure to engage lactate production when challenged with mycobacterial antigen (Mtb). ~ 15% of 2-DGtolDC express low levels of MHC class II and 30% express CD86, while they are negative for CD40. 2-DGtolDC also express increased immune checkpoint molecules PDL-1 and SIRP-1α. Antigen-specific T cell proliferation is reduced in response to 2-DGtolDC in vitro. Mtb-stimulated 2-DGtolDC do not engage aerobic glycolysis but respond to challenge via increased OXPHOS. They also have decreased levels of p65 phosphorylation, with increased phosphorylation of the non-canonical p100 pathway. A stable tolDC phenotype is associated with sustained SIRP-1α phosphorylation and p85-AKT and PI3K signalling inhibition. Further, 2-DGtolDC preferentially secrete IL-10 rather than IL-12 upon Mtb-stimulation. Importantly, a single subcutaneous administration of 2-DGtolDC prevented experimental autoimmune uveoretinitis (EAU) in vivo. Inhibiting glycolysis of autologous tolDC prior to transfer may be a useful approach to providing stable tolDC therapy for autoimmune/immune-mediated diseases.

Clean Cut (adaptive, multimodal surgical infection prevention programme) for low-resource settings: a prospective quality improvement study.

BACKGROUND: Clean Cut is an adaptive, multimodal programme to identify improvement opportunities and safety changes in surgery by enhancing outcomes surveillance, closing gaps in surgical infection prevention standards, and strengthening underlying processes of care. Surgical-site infections (SSIs) are common in low-income countries, so this study assessed a simple intervention to improve perioperative infection prevention practices in one. METHODS: Clean Cut was implemented in five hospitals in Ethiopia from August 2016 to October 2018. Compliance data were collected from the operating room focused on six key perioperative infection prevention standards. Process-mapping exercises were employed to understand barriers to compliance and identify locally driven improvement opportunities. Thirty-day outcomes were recorded on patients for whom intraoperative compliance information had been collected. RESULTS: Compliance data were collected from 2213 operations (374 at baseline and 1839 following process improvements) in 2202 patients. Follow-up was completed in 2159 patients (98·0 per cent). At baseline, perioperative teams complied with a mean of only 2·9 of the six critical perioperative infection prevention standards; following process improvement changes, compliance rose to a mean of 4·5 (P < 0·001). The relative risk of surgical infections after Clean Cut implementation was 0·65 (95 per cent c.i. 0·43 to 0·99; P = 0·043). Improved compliance with standards reduced the risk of postoperative infection by 46 per cent (relative risk 0·54, 95 per cent c.i. 0·30 to 0·97, for adherence score 3-6 versus 0-2; P = 0·038). CONCLUSION: The Clean Cut programme improved infection prevention standards to reduce SSI without infrastructure expenses or resource investments.

The Lifebox Surgical Headlight Project: engineering, testing, and field assessment in a resource-constrained setting.

BACKGROUND: Poor surgical lighting represents a major patient safety issue in low-income countries. This study evaluated device performance and undertook field assessment of high-quality headlights in Ethiopia to identify critical attributes that might improve safety and encourage local use. METHODS: Following an open call for submissions (December 2018 to January 2019), medical and technical (non-medical) headlights were identified for controlled specification testing on 14 prespecified parameters related to light quality/intensity, mounting and battery performance, including standardized illuminance measurements over time. The five highest-performing devices (differential illumination, colour rendering, spot size, mounting and battery duration) were distributed to eight Ethiopian surgeons working in resource-constrained facilities. Surgeons evaluated the devices in operating rooms, and in a comparative session rated each headlight in terms of performance and willingness to purchase. RESULTS: Of 25 submissions, eight headlights (6 surgical and 2 technical) met the criteria for full specification testing. Scores ranged from 8 to 12 (of 14), with differential performance in lighting, mounting and battery domains. Only two headlights met the illuminance parameters of more than 35 000 lux during initial testing, and no headlight satisfied all minimum specifications. Of the five headlights evaluated in Ethiopia, daily operation logbooks noted variability in surgeons' opinions of lighting quality (6-92 per cent) and spot size (0-92 per cent). Qualitative interviews also yielded important feedback, including preference for easy transport. Surgeons sought high quality with price sensitivity (using out-of-pocket funds) and identified the least expensive but high-functioning device as their first choice. CONCLUSION: No device satisfied all the predetermined specifications, and large price discrepancies were critical factors leading surgeons' choices. The favoured device is undergoing modification by the manufacturer based on design feedback so an affordable, high-quality surgical headlight crafted specifically for the needs of resource-constrained settings can be used to improve surgical safety.

ANTECEDENTES: Una iluminación quirúrgica deficiente conlleva importantes problemas de seguridad para los pacientes en países de bajos ingresos. En Etiopía, se evaluó el rendimiento y la capacidad de iluminar el campo quirúrgico de varias lámparas de alta calidad para identificar aspectos esenciales que podrían mejorar la seguridad y fomentar su uso local. MÉTODOS: Tras una convocatoria abierta (diciembre de 2018-enero de 2019), se identificaron lamparás médicas y técnicas (no médicas) para realizar un análisis de 14 variables previamente definidas en relación con la calidad/intensidad de la luz, montaje y rendimiento de la batería, además de mediciones estandarizadas de iluminancia a largo plazo. Los cinco dispositivos de mayor rendimiento (iluminación diferencial, reproducción del color, tamaño del foco, montaje y duración de la batería) se distribuyeron entre 8 cirujanos etíopes que trabajaban en instalaciones con recursos limitados. Los cirujanos evaluaron los dispositivos en quirófano y en sesiones comparativas calificaron el rendimiento de cada lámpara y la disposición para su compra. RESULTADOS: De las 25 propuestas presentadas, 8 lámparas (6 quirúrgicas y 2 técnicas) cumplieron los criterios para realizar las pruebas de especificación completas. Las puntuaciones oscilaron entre 8 y 12 (de un total de 14), con diferencias en los ámbitos de iluminación, montaje y batería. Solo 2 lámparas proporcionaron > 35000 lux de iluminancia durante la prueba inicial, y ninguna lámpara cumplió con todas las especificaciones mínimas. De las cinco lámparas evaluadas en Etiopía, hubo una gran variabilidad en las opiniones de los cirujanos anotadas en los registros realizados, tanto sobre la calidad de la iluminación (21-92%), como del tamaño del foco (0-92%). En las entrevistas cualitativas surgieron comentarios importantes como la preferencia por un transporte fácil. Los cirujanos buscaban la mejor calidad al precio más razonable (dado que se utilizaban fondos propios para su adquisición) e identificaron el dispositivo menos costoso pero con alto funcionamiento como primera opción. CONCLUSIÓN: El hecho de que ningún dispositivo satisfizo todas las especificaciones predeterminadas y la gran variabilidad de precios fueron los aspectos esenciales que determinaron la elección de los cirujanos. El dispositivo mejor valorado está siendo modificado por el fabricante en función de los comentarios de diseño, para lograr una lámpara quirúrgica asequible y de alta calidad diseñada específicamente para satisfacer las necesidades de entornos con recursos limitados en la mejora la seguridad quirúrgica.

The atypical chemokine receptor-2 does not alter corneal graft survival but regulates early stage of corneal graft-induced lymphangiogenesis.

PURPOSE: To re-evaluate the role of the atypical chemokine receptor-2 (ACKR2) in corneal graft rejection and investigate the effect of ACKR2 on inflammation-associated lymphangiogenesis using murine orthotopic corneal transplantation. METHODS: Corneal grafts were performed and evaluated in the settings of syngeneic, allogeneic and single antigen (HY-antigen) disparity pairings. Corneal vessels were quantified in whole mounts from WT, ACKR2-/- and F4/80-/-ACKR2-/- mice that received syngeneic or allogeneic grafts using anti-CD31 and anti-Lyve-1 antibodies. RESULTS: Syngeneic corneal grafts in WT and ACKR2-/- mice were 100% accepted. Fully histo-incompatible allogeneic grafts were rapidly rejected (100%) with similar tempo in both WT and ACKR2-/- hosts. Around 50% of single-antigen (HY) disparity grafts rejected at a slow but similar tempo (60 days) in WT and ACKR2-/- mice. Prior to grafting, F4/80-/-ACKR2-/- mice had lower baseline levels of limbal blood and lymphatic vessels compared to ACKR2-/- mice. Syngeneic grafts, but not allogeneic grafts, in ACKR2-/- and F4/80-/-ACKR2-/- mice induced higher levels of lymphatic sprouting and infiltration of Lyve-1+ cells during the early (3d) post-graft (pg) stage but lymphatic density was similar to WT grafted mice by 7d pg. CONCLUSIONS: Our results indicate that the chemokine scavenger receptor, ACKR2, has no role to play in the survival of allogeneic grafts. A minor role in regulation of lymphangiogenesis in the early stage of wound healing in syngeneic grafts is suggested, but this effect is probably masked by the more pronounced lymphangiogenic inflammatory response in allogeneic grafts. No additional effect was observed with the deletion of the resident macrophage gene, F4/80.

Temporal trends and sources of variation in carbon flux from coarse woody debris in experimental forest canopy openings.

Pulses of respiration from coarse woody debris (CWD) have been observed immediately following canopy disturbances, but it is unclear how long these pulses are sustained. Several factors are known to influence carbon flux rates from CWD, but few studies have evaluated more than temperature and moisture. We experimentally manipulated forest structure in a second-growth northern hardwood forest and measured CO2 flux periodically for seven growing seasons following gap creation. We present an analysis of which factors, including the composition of the wood-decay fungal community influence CO2 flux. CO2 flux from CWD was strongly and positively related to wood temperature and varied significantly between substrate types (logs vs. stumps). For five growing seasons after treatment, the CO2 flux of stumps reached rates up to seven times higher than that of logs. CO2 flux of logs did not differ significantly between canopy-gap and closed-canopy conditions in the fourth through seventh post-treatment growing seasons. By the seventh season, the seasonal carbon flux of both logs and stumps had decreased significantly from prior years. Linear mixed models indicated the variation in the wood inhabiting fungal community composition explained a significant portion of variability in the CO2 flux along with measures of substrate conditions. CO2 flux rates were inversely related to fungal diversity, with logs hosting more species but emitting less CO2 than stumps. Overall, our results suggest that the current treatment of CWD in dynamic forest carbon models may be oversimplified, thereby hampering our ability to predict realistic carbon fluxes associated with wood decomposition.

Prevalence of malnutrition in children under five and school-age children in Milot Valley, Haiti.

OBJECTIVES: This research aims to provide child malnutrition prevalence data from Haiti's Milot Valley to inform the design and implementation of local health interventions. STUDY DESIGN: This cross-sectional study measured underweight, stunting, and wasting/thinness using international growth standards. METHODS: Anthropometric measurements (height/length and weight) were taken on a convenience sample of 358 children aged 0-14 years. Participants were recruited through door-to-door field visits at five recruitment sites in the Milot Valley, including individuals in the waiting area of the Pediatric Outpatient Clinic at Hôpital Sacré Coeur. Caregivers were asked questions about the child's health history, including past and current feeding practices. RESULTS: Combining moderate and severe forms of malnutrition, 14.8% of children under five were stunted, 15.3% were wasted, and 16.1% were underweight. Among children 5-14 years of age, 14.1% were stunted, 7.6% were thin (low body mass index (BMI)-for-age), and 14.5% were underweight. For children under five, 42% of mothers ended exclusive breastfeeding before the recommended six months. CONCLUSION: This study illustrates the local magnitude of childhood malnutrition and can serve as a resource for future child health interventions in the Milot Valley. To fight malnutrition, a multipronged, integrated approach is recommended, combining effective community outreach and monitoring, inpatient and outpatient nutrition therapy, and expanded partnerships with nutrition-related organizations in the region.

Colitis in a transgenic mouse model of autoimmune uveitis may be induced by neoantigen presentation in the bowel.

Undifferentiated uveitis (intraocular inflammation, IOI) is an idiopathic sight-threatening, presumed autoimmune disease, accountable for ~ 10% of all blindness in the developed world. We have investigated the association of uveitis with inflammatory bowel disease (IBD) using a mouse model of spontaneous experimental autoimmune uveoretinitis (EAU). Mice expressing the transgene (Tg) hen egg lysozyme (HEL) in the retina crossed with 3A9 mice expressing a transgenic HEL-specific TCR spontaneously develop uveoretinitis at post-partum day (P)20/21. Double transgenic (dTg TCR/HEL) mice also spontaneously develop clinical signs of colitis at ~ P30 with diarrhoea, bowel shortening, oedema and lamina propria (LP) inflammatory cell infiltration. Single (s)Tg TCR (3A9) mice also show increased histological LP cell infiltration but no bowel shortening and diarrhoea. dTg TCR/HEL mice are profoundly lymphopenic at weaning. In addition, dTg TCR/HEL mice contain myeloid cells which express MHC Class II-HEL peptide complexes (MHCII-HEL), not only in the inflamed retina but also in the colon and have the potential for antigen presentation. In this model the lymphopenia and reduction in the absolute Treg numbers in dTg TCR/HEL mice is sufficient to initiate eye disease. We suggest that cell-associated antigen released from the inflamed eye can activate colonic HEL-specific T cells which, in a microbial micro-environment, not only cause colitis but feedback to amplify IOI.

The association of HIV viral load with indirect markers of liver injury.

This study assessed the association of HIV RNA with indirect markers of liver injury including FIB-4 index, liver enzymes and platelet counts in a high-risk Hispanic population. The data were derived from a prospective study that included 138 HIV/hepatitis C (HCV)-coinfected and 68 HIV-infected participants without hepatitis C or B co-infection (mono-infected). In unadjusted analyses, detectable HIV viral load (vs undetectable, <400 copies/mL) was associated with a 40% greater odds (OR 1.4, 95% CI: 1.1-1.9, P = 0.016) of FIB-4 > 1.45 in the HIV/HCV-coinfected group and 70% greater odds of FIB-4 > 1.45 (OR 1.7, 95% CI: 1.0-2.8; P = 0.046) in the HIV-mono-infected group. In multivariable analyses, a 1 log(10) increase in HIV RNA was associated with a median increase in FIB-4 of 12% in the HIV/HCV-coinfected group and 11% in the HIV-mono-infected group (P < 0.0001). Among the HIV/HCV-coinfected group, the elevating effect of HIV RNA on FIB-4 was strongest at low CD4 counts (P = 0.0037). Among the HIV-mono-infected group, the association between HIV RNA and FIB-4 was independent of CD4 cell counts. HIV RNA was associated with alterations in both liver enzymes and platelet counts. HIV antiretroviral therapy was not associated with any measure of liver injury examined. This study suggests that HIV may have direct, injurious effects on the liver and that HIV viral load should be considered when these indirect markers are used to assess liver function.

The individual and combined influence of HIV and hepatitis C virus on dyslipidaemia in a high-risk Hispanic population.

OBJECTIVES: To assess the effects of chronic hepatitis C (HCV) and HIV infection on dyslipidaemia in a Hispanic population at high risk of insulin resistance. METHODS: We compared serum lipids and C-reactive protein (CRP) in 257 Hispanic adults including 47 HIV- mono-infected, 43 HCV-mono-infected and 59 HIV/HCV-co-infected individuals as well as 108 healthy controls. We also assessed the effect of HCV on lipid alterations associated with antiretroviral therapy (ART), and the impact of HCV and HIV on the associations among insulin resistance, triglycerides and cholesterol. RESULTS: HCV infection was associated with lower total and low-density lipoprotein (LDL) cholesterol, but not high-density lipoprotein (HDL) cholesterol or triglycerides compared with healthy controls. HIV infection was associated with higher triglycerides and lower HDL, but not total or LDL cholesterol. HCV mitigated the elevation of triglycerides associated with ART. In healthy Hispanic adults, insulin resistance was significantly correlated with higher triglycerides, CRP and lower HDL. HIV infection nullified the association of insulin resistance with triglycerides and HDL, and the association of triglycerides with LDL. HCV infection nullified the association of insulin resistance with triglycerides, HDL and CRP. CONCLUSIONS: HCV co-infection alters the profile of HIV-associated dyslipidaemia. The clinical significance of these findings for cardiovascular complications in HIV merits further study.

Adhesion of cells to polystyrene surfaces.

The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polystyrene. This technique together with various oxidation techniques that render surfaces suitable for cell culture generated high surface densities of hydroxyl groups. The importance of surface hydroxyl groups for the adhesion of baby hamster kidney cells or leukocytes was demonstrated by the inhibition of adhesion when these groups were blocked: blocking of carboxyl groups did not inhibit adhesion and may raise the adhesion of a surface. These results applied to cell adhesion in the presence and absence of serum. The relative unimportance of fibronectin for the adhesion and spreading of baby hamster kidney cells to hydroxyl-rich surfaces was concluded when cells spread on such surfaces after protein synthesis was inhibited with cycloheximide, fibronectin was removed by trypsinization, and trypsin activity was stopped with leupeptin.

Chemokinetic accumulation of human neutrophils on immune complex-coated substrata: analysis at a boundary.

The locomotory behavior of human blood neutrophil leukocytes was studied at a boundary between two surfaces with different chemokinetic properties. This was achieved by time-lapse cinematography of neutrophils moving on coverslips coated with BSA, then part-coated with immune complexes by adding anti-BSA IgG with a straight-line boundary between the BSA and the immune complexes. Cell locomotion was filmed in microscopic fields bisected by the boundary, and kinetic behavior was assessed by comparing speed (orthokinesis), turning behavior (klinokinesis), and the rate of diffusion of the cells on each side of the boundary, using a recently described mathematical analysis of kinesis. In the absence of serum or complement, the proportion of motile cells and their speed and rate of diffusion were greater on BSA than on antiBSA, but there was no consistent difference in turning behavior between cells on the two surfaces. The immune complexes were therefore negatively chemokinetic in comparison with BSA, and this resulted from a negative orthokinesis with little or no contribution from klinokinesis. As would be predicted theoretically, this resulted in gradual accumulation of cells on the immune complexes even in the absence of a chemotactic factor. In further studies, a parallel plate flow chamber was used to show that, under conditions of flow, neutrophils accumulated much more rapidly on a surface coated with BSA-anti-BSA than on BSA alone. Moreover, neutrophils on immune complex-coated surfaces lost their ability to form rosettes with IgG-coated erythrocytes. This suggests that neutrophils on immune complex-coated surfaces redistribute their Fc receptors (RFc gamma) to the under surface, and that the lowered speed of locomotion is due to tethering of neutrophils by substratum-bound IgG-Fc.

STAT1 expression is not required for polyp formation in Min mice.

Recent studies have suggested the importance of interleukin (IL)-6 signaling in the development of colon cancer. Expression of IL-6 and the IL-6 receptor have been found to be elevated in colorectal carcinoma tissue, and IL-6 has been found to be critical for tumor formation in mouse models of colon cancer. IL-6 mediated activation of the transcription factor STAT1 has been shown to be important in protection of colorectal carcinoma cells from apoptotic signals. To test the hypothesis that the IL-6-STAT1 axis plays a role in early stages of colon cancer development, we examined the role of this pathway in the mouse multiple intestinal neoplasia (Min) model of intestinal tumorigenesis. Due to low fecundity, we were unable to generate Min mice lacking expression of IL-6. We then focused on the role of STAT1 in intestinal polyp formation in these animals. Min mice lacking STAT1 or heterozygous for STAT1 developed polyps in similar numbers as those expressing STAT1. Furthermore, the anatomic distribution and histological characteristics of these polyps did not vary among these populations. These results indicate that STAT1 does not play a role in the pathogenesis of the Min model for colon cancer. However, they do not rule out the possibility that STAT1 plays a role in other stages of colon cancer development.

Predictors of insulin resistance among Hispanic adults infected with or at risk of infection with the human immunodeficiency virus and hepatitis C virus.

Both the human immunodeficiency (HIV) and hepatitis C (HCV) viruses have been associated with insulin resistance (IR). However, our understanding of the prevalence of IR, the underlying mechanisms and predisposing factors is limited, particularly among minority populations. We conducted a study of 333 Hispanic adults including: 76 HIV monoinfected, 62 HCV monoinfected, 97 HIV/HCV co-infected and 98 uninfected controls with a specific focus on HCV infection and liver injury as possible predictors of IR. IR was measured using the Quantitative Insulin Sensitivity Check Index (QUICKI). The majority (55-69%) of participants in all groups had QUICKI values <0.350. Body mass index was associated with IR in all groups. Triglycerides were associated with IR in the uninfected control group only (-1.83, SE = 0.58, P = 0.0022). HCV was associated with IR in participants infected with HIV (-0.012, SE = 0.0046, P = 0.010). Liver injury, as measured by score to assess liver injury (FIB-4) score, was significantly associated with IR independently of HCV infection (-0.0035, SE = 0.0016, P = 0.027). In the HIV/HCV co-infected group, treatment with nucleoside reverse-transcriptase (RT) inhibitors plus non-nucleoside RT inhibitors (-0.021, SE = 0.080, P = 0.048), but not protease inhibitors (-0.000042, SE = 0.0082, P = 0.96) was associated with IR. HCV infection and antiretroviral agents, including nucleoside RT inhibitor plus non-nucleoside RT inhibitor treatment are contributors to IR in HIV infection. Liver injury, as measured by the FIB-4 score, is a predictor of IR independently of HCV infection.

Drug use and weight loss in HIV-infected Hispanic men.

Weight loss is an independent risk factor for mortality in HIV but the role of drug use in HIV-related weight loss is not well described. We conducted this study to determine the role of drug use in HIV-related weight loss. Men (n=304), all of whom were Hispanic, were recruited into one of three groups: HIV-infected drug users; HIV-non-infected drug users; and HIV-infected non-drug users. Body mass index (BMI) was measured at successive visits. The groups were re-categorized based on self-reported drug use at the current visit into: (1) users of cocaine alone; (2) users of cocaine and opiates; (3) users of opiates alone; (4) former drug users; and (5) those who denied ever using drugs (all HIV-infected). The effect on BMI of the duration of use of the specific drug types was evaluated using repeated-measures analyses. Longer duration of exclusive opiate use or mixed cocaine and opiate use did not affect BMI in the men, regardless of HIV status. Exclusive cocaine use was associated with a decline in BMI among HIV-infected men (-0.070 kg/m(2) per month duration of use; SE=0.033; p=0.037) but not among HIV-uninfected men (0.024 kg/m(2) per month; SE=0.023; p=0.29). Adjustment for marijuana, cigarette and alcohol use in all men, or for CD4 count, viral load or HIV medication use in the HIV-infected men, did not alter the conclusions. We conclude that the use of opiates or combined opiates and cocaine does not increase the risk of weight loss in the presence or absence of HIV infection. Exclusive cocaine use may exacerbate weight loss in HIV-infection.

Early increase in left ventricular compliance after myocardial infarction.

The left ventricular (LV) pressure-volume (P-V) relationship is a resultant of several determinants, including initial ventricular volume, geometry, and wall stiffness. A quantitative index of one of these determinants, LV wall stiffness, was developed from a mathematical analysis of the isolated P-V relationship. Since this relationship was exponential, stiffness (dP/dV) could be expressed by the equation dP/dV = aP + b, where a and b are constants. The a constant, termed the passive elastic modulus, was independent of both pressure and volume, was modified only slightly by changes in geometry, and thus was primarily affected by changes in wall stiffness. LV wall stiffness was assessed by determination of the passive elastic modulus in eight normal canine hearts and in five hearts 1 hr after acute myocardial infarction. The value of the passive elastic modulus for the normal canine LV was found to be 0.099+/-0.006 cc(-1). In the five infarcted hearts there was a modest, but statistically insignificant, shift of the P-V curves from control, such that for the same pressure the infarcted hearts contained greater volume. However, the passive elastic modulus decreased 41% to 0.057+/-0.006 cc(-1) (P < 0.001). Thus, although LV wall stiffness may increase later in the course of myocardial infarction, it is concluded that it was significantly decreased 1 hr after infarction. Calculation of the passive elastic modulus provided a sensitive means of detecting such changes, whereas P-V curves alone were generally insensitive.

Application of conditional probability analysis to the clinical diagnosis of coronary artery disease.

Analysis of multiple noninvasive tests offers the promise of more accurate diagnosis of coronary artery disease, but discordant test responses can occur frequently and, when observed, result in diagnostic uncertainty. Accordingly, 43 patients undergoing diagnostic coronary angiography were evaluated by noninvasive testing and the results subjected to analysis using Bayes' theorem of conditional probability. The procedures used included electrocardiographic stress testing for detection of exercise-induced ST segment depression, cardiokymographic stress testing for detection of exercise-induced precordial dyskinesis, myocardial perfusion scintigraphy for detection of exercise-induced relative regional hypoperfusion, and cardiac fluoroscopy for detection of coronary artery calcification. The probability for coronary artery disease was estimated by Bayes' theorem from each patient's age, sex, and symptom classification, and from the observed test responses. This analysis revealed a significant linear correlation between the predicted probability for coronary artery disease and the observed prevalence of angiographic disease over the entire range of probability from 0 to 100% (P less than 0.001 by linear regression). The 12 patients without angiographic disease had a mean posttest likelihood of only 7.0 +/- 2.6% despite the fact that 13 of the 60 historical and test responses were falsely "positive." In contrast, the mean posttest likelihood was 94.1 +/- 2.8% in the 31 patients with angiographic coronary artery disease, although 45 of the 155 historical and test responses were falsely "negative." In 8 of the 12 normal patients, the final posttest likelihood was under 10% and in 26 of the 31 coronary artery disease patients, it was over 90%. These estimates also correlated well with the pooled clinical judgment of five experienced cardiologists (P less than 0.001 by linear regression). The observed change in probability for disease for each of the 15 different test combinations correlated with their information content predicted according to Shannon's theorem (P less than 0.001 by linear regression). These results support the use of probability analysis in the clinical diagnosis of coronary artery disease and provide a formal basis for comparing the relative diagnostic effectiveness and cost-effectiveness of different test combinations.

Regulation of insulin-like growth factor-I and its receptor in rat aorta after balloon denudation. Evidence for local bioactivity.

Local production of growth factors may play a major role in vascular repair after injury. We examined the regulation of insulin-like growth factor-I (IGF-I) and its specific membrane receptor in balloon-denuded rat aorta. Aortic IGF-I mRNA and radioimmunoassayable IGF-I content increased severalfold after balloon denudation with a peak at 7 d after injury. This coincided with a reciprocal 25% decrease in IGF-I receptor mRNA content and a 40% decrease in total 125I-IGF-I binding. Scatchard analysis indicated a single class of binding sites, with a decrease in receptor number at 7 d compared to control and no change in affinity. By in situ hybridization the predominant site of IGF-I expression in the normal and the denuded vessel wall was the medial smooth muscle cell. After denudation there was a relative decrease in IGF-I receptor mRNA in the medial cells as compared to the neointima, suggesting that the site of IGF-I action was predominantly in the medial layer. These data suggest that local expression and action of IGF-I are significant in the promotion of smooth muscle cell proliferation after arterial injury.

Clonal expansion of lung V delta 1+ T cells in pulmonary sarcoidosis.

Sarcoidosis is a multisystem disease of unknown etiology characterized by the presence of noncaseating granulomas in involved tissues. To investigate a potential role for gamma/delta T cells in the pathogenesis of pulmonary sarcoidosis, we studied lung and blood T cells from patients for preferential expression of particular gamma/delta T cell receptors. An abnormally high percentage of gamma/delta cells was found in the blood of some patients. However, the increased percentage did not reflect an increase in absolute number, and appeared to be secondary to a decrease in T cells expressing alpha/beta receptors. Furthermore, as in normals, the circulating gamma/delta cells in patients predominantly expressed V gamma 9/V delta 2 receptors, a subset that was not enriched at the site of disease. In contrast, in the lung, an increased percentage of gamma/delta cells expressing V delta 1 was found in a subset of patients. Importantly, these cells demonstrated evidence of prior activation by selectively expanding in vitro in the presence of interleukin 2. Furthermore, an analysis of junctional region sequences revealed their clonal nature. These clonal expansions of V delta 1+ cells in pulmonary sarcoidosis provide evidence for a disease process that involves specific recognition of a local antigen by T cells, and contributes new information regarding the nature of the as yet undefined antigenic stimulus.