The role of quiescent thymic progenitors in TAL/LMO2-induced T-ALL chemotolerance

Relapse in T-cell acute lymphoblastic leukemia (T-ALL) may signify the persistence of leukemia-initiating cells (L-ICs). Ectopic TAL1/LMO expression defines the largest subset of T-ALL, but its role in leukemic transformation and its impact on relapse-driving L-ICs remain poorly understood. In TAL1/LMO mouse models, double negative-3 (DN3; CD4-CD8-CD25+CD44-) thymic progenitors harbored L-ICs. However, only a subset of DN3 leukemic cells exhibited L-IC activity, and studies linking L-ICs and chemotolerance are needed. To investigate L-IC heterogeneity, we used mouse models and applied single-cell RNA-sequencing and nucleosome labeling techniques in vivo. We identified a DN3 subpopulation with a cell cycle-restricted profile and heightened TAL1/LMO2 activity, that expressed genes associated with stemness and quiescence. This dormant DN3 subset progressively expanded throughout leukemogenesis, displaying intrinsic chemotolerance and enrichment in genes linked to minimal residual disease. Examination of TAL/LMO patient samples revealed a similar pattern in CD7+CD1a- thymic progenitors, previously recognized for their L-IC activity, demonstrating cell cycle restriction and chemotolerance. Our findings substantiate the emergence of dormant, chemotolerant L-ICs during leukemogenesis, and demonstrate that Tal1 and Lmo2 cooperate to promote DN3 quiescence during the transformation process. This study provides a deeper understanding of TAL1/LMO-induced T-ALL and its clinical implications in therapy failure.

Prevalence of urinary tract cancer in the Spanish cohort of the IDENTIFY study

INTRODUCTION

Malignant tumors of the urinary tract are associated with high morbidity and mortality, and their prevalence can vary worldwide. Recently, the IDENTIFY study has published results on the prevalence of urinary tract cancer at a global level. This study evaluates the prevalence of cancer within the Spanish cohort of the IDENTIFY study to determine whether the published results can be extrapolated to our population.

PATIENTS AND METHODS

An analysis of the data from the Spanish cohort of patients in the IDENTIFY study was performed. This is a prospective cohort of patients referred to secondary care with suspected cancer, predominantly due to hematuria. Patients were recruited between December 2017 and December 2018.

RESULTS

A total of 706 patients from 9 Spanish centers were analyzed. Of these, 277 (39.2%) were diagnosed with cancer: 259 (36.7%) bladder cancer, 10 (1.4%) upper tract urothelial carcinoma, 9 (1.2%) renal cancer and 5 (0.7%) prostate cancer. Increasing age (OR 1.05 (95% CI 1.03-1.06; P < 0.001)), visible hematuria (VH) OR 2.19 (95% CI 1.13-4.24; P = 0.02)) and smoking (ex-smokers: OR 2.11(95% CI 1.30-3.40; P = 0.002); smokers: OR 2.36 (95% CI 1.40-3.95; P = 0.001)) were associated with higher probability of bladder cancer.

CONCLUSION

This study highlights the risk of bladder cancer in patients with VH and smoking habits. Bladder cancer presented the highest prevalence; higher than the prevalence reported in previous series and presented in the IDENTIFY study. Future work should evaluate other associated factors that allow us to create cancer prediction models to improve the detection of cancer in our patients.

Prostaglandin E2 stimulates cAMP signaling and resensitizes human leukemia cells to glucocorticoid-induced cell death

Glucocorticoid (GC) resistance remains a clinical challenge in pediatric acute lymphoblastic leukemia where response to GC is a reliable prognostic indicator. To identify GC resistance pathways, we conducted a genome-wide, survival-based, short hairpin RNA screen in murine T-cell acute lymphoblastic leukemia (T-ALL) cells. Genes identified in the screen interfere with cyclic adenosine monophosphate (cAMP) signaling and are underexpressed in GC-resistant or relapsed ALL patients. Silencing of the cAMP-activating Gnas gene interfered with GC-induced gene expression, resulting in dexamethasone resistance in vitro and in vivo. We demonstrate that cAMP signaling synergizes with dexamethasone to enhance cell death in GC-resistant human T-ALL cells. We find the E prostanoid receptor 4 expressed in T-ALL samples and demonstrate that prostaglandin E2 (PGE2) increases intracellular cAMP, potentiates GC-induced gene expression, and sensitizes human T-ALL samples to dexamethasone in vitro and in vivo. These findings identify PGE2 as a target for GC resensitization in relapsed pediatric T-ALL.

ESRRB regulates glucocorticoid gene expression in mice and patients with acute lymphoblastic leukemia

Synthetic glucocorticoids (GCs), such as dexamethasone and prednisone, remain key components of therapy for patients with lymphoid malignancies. For pediatric patients with acute lymphoblastic leukemia (ALL), response to GCs remains the most reliable prognostic indicator; failure to respond to GC correlates with poor event-free survival. To uncover GC resistance mechanisms, we performed a genome-wide, survival-based short hairpin RNA screen and identified the orphan nuclear receptor estrogen-related receptor-β (ESRRB) as a critical transcription factor that cooperates with the GC receptor (GR) to mediate the GC gene expression signature in mouse and human ALL cells. Esrrb knockdown interfered with the expression of genes that were induced and repressed by GR and resulted in GC resistance in vitro and in vivo. Dexamethasone treatment stimulated ESRRB binding to estrogen-related receptor elements (ERREs) in canonical GC-regulated genes, and H3K27Ac Hi-chromatin immunoprecipitation revealed increased interactions between GR- and ERRE-containing regulatory regions in dexamethasone-treated human T-ALL cells. Furthermore, ESRRB agonists enhanced GC target gene expression and synergized with dexamethasone to induce leukemic cell death, indicating that ESRRB agonists may overcome GC resistance in ALL, and potentially, in other lymphoid malignancies.

Role of central command in carotid baroreflex resetting in humans during static exercise

The purpose of the experiments was to examine the role of central command in the exercise-induced resetting of the carotid baroreflex. Eight subjects performed 30 % maximal voluntary contraction (MVC) static knee extension and flexion with manipulation of central command (CC) by patellar tendon vibration (PTV). The same subjects also performed static knee extension and flexion exercise without PTV at a force development that elicited the same ratings of perceived exertion (RPE) as those observed during exercise with PTV in order to assess involvement of the exercise pressor reflex. Carotid baroreflex (CBR) function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid changes in neck pressure and suction during steady state static exercise. Knee extension exercise with PTV (decreased CC activation) reset the CBR-HR and CBR-MAP to a lower operating pressure (P < 0.05) and knee flexion exercise with PTV (increased CC activation) reset the CBR-HR and CBR-MAP to a higher operating pressure (P < 0.05). Comparison between knee extension and flexion exercise at the same RPE with and without PTV found no difference in the resetting of the CBR-HR function curves (P > 0.05) suggesting the response was determined primarily by CC activation. However, the CBR-MAP function curves were reset to operating pressures determined by both exercise pressor reflex (EPR) and central command activation. Thus the physiological response to exercise requires CC activation to reset the carotid-cardiac reflex but requires either CC or EPR to reset the carotid-vasomotor reflex.

Sensitivity of dissolution rate to location in the paddle dissolution apparatus

The aim of the present study was to determine the apparent diffusion boundary layer and dissolution rate constant for various surfaces of compacts and at various locations in the USP paddle dissolution apparatus. Benzoic acid compacts were coated with paraffin wax leaving only the surface under investigation free for dissolution. The dissolution rates for various surfaces at varying locations in the paddle dissolution vessel were determined from the slope of the dissolution profile (amount dissolved (mg) versus time (min)). The apparent diffusion boundary layer and dissolution rate constant were calculated and were found to vary depending on the surface of the compact from which dissolution took place and also on the location and size of the compact. It may be concluded that, in developing models to describe the dissolution from solid dosage forms, it is not accurate to assume constant hydrodynamics and mass transfer rates at all surfaces of the system, or in different locations within the test device. A more exact description of the hydrodynamics would be necessary in order to precisely model drug dissolution in the paddle dissolution apparatus.

Increases in intramuscular pressure raise arterial blood pressure during dynamic exercise

This investigation was designed to determine the role of intramuscular pressure-sensitive mechanoreceptors and chemically sensitive metaboreceptors in affecting the blood pressure response to dynamic exercise in humans. Sixteen subjects performed incremental (20 W/min) cycle exercise to fatigue under four conditions: control, exercise with thigh cuff occlusion of 90 Torr (Cuff occlusion), exercise with lower body positive pressure (LBPP) of 45 Torr, and a combination of thigh cuff occlusion and LBPP (combination). Indexes of central command (heart rate, oxygen uptake, ratings of perceived exertion, and electromyographic activity), cardiac output, stroke volume, and total peripheral resistance were not significantly different between the four conditions. Mechanical stimulation during LBPP and combination conditions resulted in significant elevations in intramuscular pressure and mean arterial pressure from control at rest and throughout the incremental exercise protocol (P < 0.05). Conversely, there existed no significant changes in mean arterial pressure when the metaboreflex was stimulated by cuff occlusion. These findings suggest that under normal conditions the mechanoreflex is tonically active and is the primary mediator of exercise pressor reflex-induced alterations in arterial blood pressure during submaximal dynamic exercise in humans.

Effects of partial neuromuscular blockade on carotid baroreflex function during exercise in humans

1. This investigation was designed to determine the contribution of central command to the resetting of the carotid baroreflex during static and dynamic exercise in humans. 2. Thirteen subjects performed 3.5 min of static one-legged exercise (20 % maximal voluntary contraction) and 7 min dynamic cycling (20 % maximal oxygen uptake) under two conditions: control (no intervention) and with partial neuromuscular blockade (to increase central command influence) using Norcuron (curare). Carotid baroreflex function was determined at rest and during steady-state exercise using a rapid neck pressure/neck suction technique. Whole-body Norcuron was repeatedly administered to effectively reduce hand-grip strength by approximately 50 % of control. 3. Partial neuromuscular blockade increased heart rate, mean arterial pressure, perceived exertion, lactate concentration and plasma noradrenaline concentration during both static and dynamic exercise when compared to control (P < 0.05). No effect was seen at rest. Carotid baroreflex resetting was augmented from control static and dynamic exercise by partial neuromuscular blockade without alterations in gain (P < 0.05). In addition, the operating point of the reflex was relocated away from the centring point (i.e. closer to threshold) during exercise by partial neuromuscular blockade (P < 0.05). 4. These findings suggest that central command actively resets the carotid baroreflex during dynamic and static exercise.

Effects of exercise pressor reflex activation on carotid baroreflex function during exercise in humans

1. This investigation was designed to determine the contribution of the exercise pressor reflex to the resetting of the carotid baroreflex during exercise. 2. Ten subjects performed 3.5 min of static one-legged exercise (20 % maximal voluntary contraction) and 7 min dynamic cycling (20 % maximal oxygen uptake) under two conditions: control (no intervention) and with the application of medical anti-shock (MAS) trousers inflated to 100 mmHg (to activate the exercise pressor reflex). Carotid baroreflex function was determined at rest and during exercise using a rapid neck pressure/neck suction technique. 3. During exercise, the application of MAS trousers (MAS condition) increased mean arterial pressure (MAP), plasma noradrenaline concentration (dynamic exercise only) and perceived exertion (dynamic exercise only) when compared to control (P < 0.05). No effect of the MAS condition was evident at rest. The MAS condition had no effect on heart rate (HR), plasma lactate and adrenaline concentrations or oxygen uptake at rest and during exercise. The carotid baroreflex stimulus-response curve was reset upward on the response arm and rightward to a higher operating pressure by control exercise without alterations in gain. Activation of the exercise pressor reflex by MAS trousers further reset carotid baroreflex control of MAP, as indicated by the upward and rightward relocation of the curve. However, carotid baroreflex control of HR was only shifted rightward to higher operating pressures by MAS trousers. The sensitivity of the carotid baroreflex was unaltered by exercise pressor reflex activation. 4. These findings suggest that during dynamic and static exercise the exercise pressor reflex is capable of actively resetting carotid baroreflex control of mean arterial pressure; however, it would appear only to modulate carotid baroreflex control of heart rate.

Mechanistic aspects of the release of levamisole hydrochloride from biodegradable polymers

The release of levamisole hydrochloride from poly-DL-lactide-co-glycolide compacts prepared at 5, 10 and 20% drug loading using two different particle size fractions of drug (90-125 and 125-250 microm) was investigated. Release profiles were significantly different from those previously reported for compacts prepared using the base form of the drug. Release was found to occur in a biphasic manner, with an initial fast release phase followed by a slower polymer degradation controlled release phase. The drug release profiles were successfully described by a model combining contributions from a first-order initial release phase and a polymer degradation controlled drug release phase. The fraction of drug released in the initial burst phase (F(B)) was attributed to the dissolution of drug domains situated at the surface of the polymer-drug compact and this fraction tended to increase with increasing drug particle size, as expected from the model. The increase in F(B) with increased loading was attributed to the clumping of dispersed drug particles which effectively increased the proportion of drug linked to the compact surface.

Estimation of completeness of AIDS case reporting in Massachusetts

One of the most important aspects of any surveillance system is degree of completeness. We conducted a multiple source capture-recapture study using the 1994 Massachusetts Uniform Hospital Discharge Data Set (UHDDS) and Medicaid claims data to evaluate the completeness of the state's AIDS registry. We used encrypted social security numbers as the primary link to ensure confidentiality. For cases that did not link in the first round owing to missing social security numbers, we linked using gender and date of birth. Staff reviewed unmatched records from the Uniform Hospital Discharge Data Set and Medicaid datasets to determine subjects' AIDS case status. Using the Uniform Hospital Discharge Data Set, the AIDS registry was 92.6% complete (95% confidence interval (CI) = 91.6-93.5). The Medicaid claims dataset suggested the AIDS registry to be 94.5% complete (95% confidence interval = 93.7-95.3). The completeness of reporting to the state AIDS registry continues to be high, but there are differences by gender and mode of transmission of the virus. The continued assessment of completeness of reporting is important to ensure quality of the surveillance database over time.

Carotid baroreflex function during prolonged exercise

The present investigation was designed to uncouple the hemodynamic physiological effects of thermoregulation from the effects of a progressively increasing central command activation during prolonged exercise. Subjects performed two 1-h bouts of leg cycling exercise with 1) no intervention and 2) continuous infusion of a dextran solution to maintain central venous pressure constant at the 10-min pressure. Volume infusion resulted in a significant reduction in the decrement in mean arterial pressure seen in the control exercise bout (6.7 +/- 1.8 vs. 11.6+/- 1.3 mmHg, respectively). However, indexes of central command such as heart rate and ratings of perceived exertion rose to a similar extent during both exercise conditions. In addition, the carotid-cardiac baroreflex stimulus-response relationship, as measured by using the neck pressure-neck suction technique, was reset from rest to 10 min of exercise and was further reset from 10 to 50 min of exercise in both exercise conditions, with the operating point being shifted toward the reflex threshold. We conclude that the progressive resetting of the carotid baroreflex and the shift of the reflex operating point render the carotid-cardiac reflex ineffectual in counteracting the continued decrement in mean arterial pressure that occurs during the prolonged exercise.

Ventilatory responses to dynamic exercise elicited by intramuscular sensors

PURPOSE

Eight subjects, aged 27.0+/-1.6 yr, performed incremental workload cycling to investigate the contribution of skeletal muscle mechano- and metaboreceptors to ventilatory control during dynamic exercise.

METHODS

Each subject performed four bouts of exercise: exercise with no intervention (CON); exercise with bilateral thigh cuffs inflated to 90 mm Hg (CUFF); exercise with application of lower-body positive pressure (LBPP) to 45 torr (PP); and exercise with 90 mm Hg thigh cuff inflation and 45 torr LBPP (CUFF+PP). Ventilatory responses and pulmonary gas exchange variables were collected breath-by-breath with concomitant measurement of leg intramuscular pressure.

RESULTS

Ventilation (VE) was significantly elevated from CON during PP and CUFF+PP at workloads corresponding to > or = 60% CON peak oxygen uptake (VO2peak) and during CUFF at workloads > or = 80% CON VO2peak, P < 0.05. The VO2 at which ventilatory threshold occurred was significantly reduced from CON (2.17+/-0.28 L x min(-1)) to 1.60+/-0.19 L x min(-1), 1.45+/-0.15 L x min(-1), and 1.15+/-0.11 L x min(-1) during CUFF, PP, and CUFF+PP, respectively. The slope of the linear regression describing the VE/CO2 output relationship was increased from CON by approximately 22% during CUFF, 40% during PP, and 41% during CUFF+PP.

CONCLUSIONS

As intramuscular pressure was significantly elevated immediately upon application of LBPP during PP and CUFF+PP without a concomitant increase in VE, it seems unlikely that LBPP-induced increases in VE can be attributed to activation of the mechanoreflex. These findings suggest that LBPP-induced reductions in perfusion pressure and decreases in venous outflow resulting from inflation of bilateral thigh cuffs may generate a metabolite sensitive intramuscular ventilatory stimulus.

Diminished forearm vasomotor response to central hypervolemic loading in aerobically fit individuals

The aim of this study was to test the hypothesis that cardiopulmonary baroreflex control of forearm vascular resistance (FVR) during central hypervolemic loading was less sensitive in exercise trained high fit individuals (HF) compared to untrained average fit individuals (AF). Eight AF (age: 24 +/- 1 yr and weight: 78.9 +/- 1.7 kg) and eight HF (22 +/- 1 yr 79.5 +/- 2.4 kg) voluntarily participated in the investigation. Maximal aerobic power (determined on a treadmill), plasma volume and blood volume (Evans blue dilution method) were significantly greater in the HF than AF (60.8 +/- 0.7 vs. 41.2 +/- 1.9 ml.kg-1.min-1, 3.96 +/- 0.17 vs 3.36 +/- 0.08 1, and 6.33 +/- 0.23 vs 5.28 +/- 0.13 1). Baseline heart rate (HR), central venous pressure (CVP), mean arterial pressure (MAP, measured by an intraradial catheter or a Finapres finger cuff), forearm blood flow (FBF, plethysmography), and FVR, calculated from the ratio (MAP-CVP)/FBF, were not different between the HF and the AF. Lower body negative pressure (LBNP, -5, -10, -15, and -20 torr) and passive leg elevation (LE, 50 cm) combined with lower body positive pressure (LBPP, +5, +10, and +20 torr) were utilized to elicit central hypovolemia and hypervolemia, respectively. Range of CVP (from LBNP to LE+LBPP) was similar in the AF (from -3.9 to +1.9 mm Hg) and HF (from -4.0 to +2.2 mm Hg). However, FVR/CVP was significantly less in the HF (-1.8 +/- 0.1 unit.mm Hg-1) than AF (-34 +/- 0.1 unit.mm Hg-1). The FVR decrease in response to increase in CVP was significantly diminished in the HF (-1.46 +/- 0.45 unit.mm Hg-1) compared to the AF (-4.40 +/- 0.97 unit.mm Hg-1), and during LBNP induced unloading the FVR/CVP of the HF (-2.01 +/- 0.49 unit.mm Hg-1) was less (P < 0.08) than the AF (-3.28 +/- 0.69 unit.mm Hg-1). We concluded that the cardiopulmonary baroreceptor mediated FVR reflex response was significantly less sensitive to changes in CVP in individuals who practice exercise training.

Arterial and cardiopulmonary baroreflexes in 60- to 69- vs. 18- to 36-yr-old humans

This study was designed to test the hypothesis that aging diminished baroreflex function during central hypovolemia. Eleven healthy young and eleven older (age 60-69 yr) individuals were assessed by using heart rate (HR) and mean arterial pressure (MAP) responses to neck pressure and suction during rest and lower body negative pressure (LBNP) of -15 Torr. The slope of forearm vascular resistance to central venous pressure during low-level LBNP was assessed as the index of cardiopulmonary baroreflex sensitivity. Baseline cardiovascular variables were not significantly different between the groups. In addition, there was no group difference in cardiopulmonary baroreflex (-3.6 vs. -3.7 units/mmHg for young vs. older, respectively) or carotid baroreflex (-0.39 vs. -0.35 beats.min-1.mmHg-1 and -0.26 vs. -0.35 mmHg/mmHg, for young vs. older, respectively) sensitivity. LBNP did not affect either HR or MAP, whereas it decreased CVP and increased FVR in both groups. LBNP significantly augmented the carotid-HR (-0.47 +/- 0.03 beats.min-1.mmHg-1) and carotid-MAP (-0.42 +/- 0.04 mmHg/mmHg) reflex gains in the young subjects only. We concluded that there was no difference in the discrete baroreflex function between the two age groups; however, the interaction of cardiopulmonary baroreceptors with carotid baroreflex function was absent in the older subjects, suggesting that the central integration of afferent neural inputs from the discrete baroreceptors was altered with aging.

AIDS among the homeless of Boston: a cohort study

We wanted to compare demographics, risk behaviors, AIDS-defining diagnoses, and survival between homeless and housed persons with AIDS in Boston from 1983 to 1991. Our retrospective cohort study used chart review to identify homeless AIDS cases and data from the Massachusetts AIDS Surveillance Program for comparison of homeless and nonhomeless cases. Seventy-two homeless and 1,536 nonhomeless Boston residents were reported to have AIDS between Jan. 1, 1983, and July 1, 1991. Homeless persons with AIDS were more likely to be African American or Latino (81 vs. 39%, p < 0.0001) and have i.v. drug use as a risk behavior (75 vs. 19%, p < 0.0001). The AIDS-defining diagnoses among the homeless were more commonly disseminated Mycobacterium tuberculosis (9 vs. 2%, p < 0.0001) and esophageal candidiasis (17 vs. 9%, p < 0.01). These differences were not seen when the populations were stratified by i.v. drug use. No significant difference in survival between the homeless and nonhomeless cohorts was found. Homeless individuals with human immunodeficiency virus are significantly different than housed persons, and at greater risk of invasive opportunistic infections. Appropriate clinical strategies can be developed to provide needed care to homeless persons with HIV.

The Boulder and/or the Vail model: training preferences of clinical psychologists

This study examined the preferences of Division 12 members (N=442) for doctoral training models (Boulder,Vail, equally Boulder and Vail) as a function of the respondent's own training program and current professional activities. Fifty percent favored the Boulder model, 14% the Vail model, and the remaining 36% both equally. However, as expected, preferences varied reliably according to one's doctoral training: Only 7% of the psychologists trained in a strong Boulder tradition preferred the Vail model, while only 10% of those trained in a strong Vail tradition favored the Boulder model. Current activities also were related systematically to training preference. These results argue for a more informed and restrained dialogue on the issue, which should be guided by the light of data rather than the heat of passion.