Evaluation and Surgical Management of Multiple Endocrine Neoplasias.

Multiple endocrine neoplasia (MEN) syndromes are rare autosomal dominant diseases that are associated with a mixture of both endocrine and non-endocrine tumors. Traditionally, there are 2 types of MEN that have unique clinical associations: MEN 1 (parathyroid hyperplasia, pancreatic neuroendocrine tumors, and pituitary tumors) and MEN 2 (medullary thyroid carcinoma and pheochromocytoma), which is further classified into MEN 2A (adds parathyroid adenomas) and 2B (adds ganglioneuromas and marfanoid habitus). Many of the endocrine tumors are resected surgically, and the pre, intra, and postoperative management strategies used must take into account the high recurrence rates asscioated with MEN tumors.

Overexpression of human DNA polymerase theta is a biomarker of aggressive and DNA repair-deficient papillary thyroid cancers.

BACKGROUND: DNA polymerase theta (POLQ) is an enzyme that repairs double-strand DNA breaks. POLQ is overexpressed in several cancer types, and increased expression is associated with a poor prognosis. Ablating POLQ function in vitro increases drug sensitivity to agents that cause double-strand DNA breaks, including chemotherapies and ionizing radiation. POLQ's role in thyroid cancer remains poorly understood. METHODS: Expression of POLQ and other genes of interest were analyzed in 513 papillary thyroid cancers (505 primary tumors and 8 metastatic lesions) and 59 normal thyroid samples available in the Cancer Genome Atlas. The Cancer Genome Atlas RNA and DNA sequencing data were queried with the Xena platform. The Recombination Proficiency Score was calculated to assess DNA repair efficiency. Other signaling events associated with thyroid tumorigenesis and clinical outcomes were analyzed. Univariate and multivariate analyses were performed. Treatment with the POLQ inhibitors ART558 and Novobiocin tested the effect of POLQ inhibition on in vitro thyroid cancer growth. RESULTS: POLQ expression was increased in papillary thyroid cancers compared to normal thyroid tissue (P < .05). POLQ expression levels were inversely correlated with Recombination Proficiency Score levels (P < .05). POLQ expression was highest in tall cell papillary thyroid cancers and in metastases. Higher POLQ expression was also associated with dedifferentiation, BRAF signaling, and shorter progression-free intervals (P < .05). Treatment with POLQ inhibitors decreased in vitro thyroid cancer growth (P < .05). CONCLUSION: These findings suggest that increased POLQ expression could serve as a valuable clinical marker and a potential therapeutic target in the treatment of thyroid cancer.

Cost-Effectiveness of Parathyroid Cryopreservation and Autotransplantation.

Importance: Delayed autotransplantation of cryopreserved parathyroid tissue (DACP) is the only surgical treatment for permanent postoperative hypoparathyroidism. Studies suggest that only a small minority of cryopreserved samples are ultimately autotransplanted with highly variable outcomes. For these reasons, many have questioned the economic utility of the process, although, to the authors' knowledge, this has never been formally studied. Objective: To report the clinical outcomes of parathyroid cryopreservation and DACP at a large academic institution and to determine the cost-effectiveness of this treatment. Design, Setting, and Participants: An institutional review board-approved, retrospective review of patients at a single institution who underwent DACP over a 17-year period was conducted with a median follow-up of 48.2 months. A forward-looking cost-utility analysis was then performed to determine the economic utility of cryopreservation/DACP vs usual care (monitoring and supplementation). Patients who had parathyroid tissue in cryopreserved storage between August 2005 to September 2022 at a single-center, academic, quaternary care center were identified. Exposure: Parathyroid cryopreservation and DACP. Main Outcomes and Measures: Graft functionality, clinical outcomes, and cost utility using a willingness-to-pay threshold of $100 000 per quality-adjusted life-year (QALY). Results: A total of 591 patients underwent cryopreservation. Of these, 10 patients (1.7%; mean [SD] age, 45.6 [17.9] years; 6 male [60%]) underwent DACP. A minority of autografts (2 [20%]) were subsequently fully functional, one-half (5 [50%]) were partially functional, and 3 (30%) were not functional. The cost-utility model estimated that at a large academic center over 10 years, the additional cost of 591 patients undergoing cryopreservation and 10 patients undergoing autotransplantation would be $618 791.64 (2022 dollars) and would add 8.75 QALYs, resulting in a cost per marginal QALY of $70 719.04, which is less than the common willingness-to-pay threshold of $100 000/QALY. Conclusions and Relevance: The reimplantation rate of cryopreserved tissue was low (<2%), but when implanted, autografts were at least partially functional 70% of the time. In the first-ever, to the authors' knowledge, formal cost analysis for this treatment, results of the current model suggest that cryopreservation and autotransplantation were cost-effective compared with the usual care for hypoparathyroidism at a large, academic institution. It is recommended that each surgical center consider whether the economic and logistical commitments necessary for cryopreservation are worthwhile for their individual needs.

Epigenetic MLH1 silencing concurs with mismatch repair deficiency in sporadic, naturally occurring colorectal cancer in rhesus macaques.

BACKGROUND: Naturally occurring colorectal cancers (CRC) in rhesus macaques share many features with their human counterparts and are useful models for cancer immunotherapy; but mechanistic data are lacking regarding the comparative molecular pathogenesis of these cancers. METHODS: We conducted state-of-the-art imaging including CT and PET, clinical assessments, and pathological review of 24 rhesus macaques with naturally occurring CRC. Additionally, we molecularly characterized these tumors utilizing immunohistochemistry (IHC), microsatellite instability assays, DNAseq, transcriptomics, and developed a DNA methylation-specific qPCR assay for MLH1, CACNA1G, CDKN2A, CRABP1, and NEUROG1, human markers for CpG island methylator phenotype (CIMP). We furthermore employed Monte-Carlo simulations to in-silico model alterations in DNA topology in transcription-factor binding site-rich promoter regions upon experimentally demonstrated DNA methylation. RESULTS: Similar cancer histology, progression patterns, and co-morbidities could be observed in rhesus as reported for human CRC patients. IHC identified loss of MLH1 and PMS2 in all cases, with functional microsatellite instability. DNA sequencing revealed the close genetic relatedness to human CRCs, including a similar mutational signature, chromosomal instability, and functionally-relevant mutations affecting KRAS (G12D), TP53 (R175H, R273*), APC, AMER1, ALK, and ARID1A. Interestingly, MLH1 mutations were rarely identified on a somatic or germline level. Transcriptomics not only corroborated the similarities of rhesus and human CRCs, but also demonstrated the significant downregulation of MLH1 but not MSH2, MSH6, or PMS2 in rhesus CRCs. Methylation-specific qPCR suggested CIMP-positivity in 9/16 rhesus CRCs, but all 16/16 exhibited significant MLH1 promoter hypermethylation. DNA hypermethylation was modelled to affect DNA topology, particularly propeller twist and roll profiles. Modelling the DNA topology of a transcription factor binding motif (TFAP2A) in the MLH1 promoter that overlapped with a methylation-specific probe, we observed significant differences in DNA topology upon experimentally shown DNA methylation. This suggests a role of transcription factor binding interference in epigenetic silencing of MLH1 in rhesus CRCs. CONCLUSIONS: These data indicate that epigenetic silencing suppresses MLH1 transcription, induces the loss of MLH1 protein, abrogates mismatch repair, and drives genomic instability in naturally occurring CRC in rhesus macaques. We consider this spontaneous, uninduced CRC in immunocompetent, treatment-naïve rhesus macaques to be a uniquely informative model for human CRC.

Total-Body Irradiation Alters White Matter Volume and Microstructural Integrity in Rhesus Macaques.

PURPOSE: Long-term survivors of brain irradiation can experience irreversible injury and cognitive impairment. T1-weighted and diffusion tensor magnetic resonance imaging (MRI) are used to evaluate brain volume and white matter (WM) microstructure in neurodevelopmental and neurodegenerative conditions. The goal of this study was to evaluate the long-term effects of single-dose total-body irradiation (TBI) or TBI with 5% partial-body sparing on brain volumetrics and WM integrity in macaques. METHODS AND MATERIALS: We used MRI scans from a cohort of male rhesus macaques (age range, 3.6-22.8 years) to compare global and regional brain volumes and WM diffusion in survivors of TBI (T1-weighted, n = 137; diffusion tensor imaging, n = 121; dose range, 3.5-10 Gy) with unirradiated controls (T1-weighted, n = 48; diffusion tensor imaging, n = 38). RESULTS: In all regions of interest, radiation affected age-related changes in fractional anisotropy, which tended to increase across age in both groups but to a lesser extent in the irradiated group (interaction P < .01). Depending on the region of interest, mean diffusivity decreased or remained the same across age in unirradiated animals, whereas it increased or did not change in irradiated animals. The increases in mean diffusivity were driven by changes in radial diffusivity, which followed similar trends across age. Axial diffusivity did not differ by irradiation status. Age-related changes in relative volumes in controls reflected normal trends in humans, with increasing WM and decreasing gray matter until middle age. Cerebrospinal fluid (CSF) volume did not differ across age in controls. WM volume was lower and CSF volume was higher in young irradiated macaques. WM volume was similar between groups, and CSF volume lower in older irradiated macaques. Gray matter volume was unaffected by radiation. CONCLUSIONS: TBI results in delayed WM expansion and long-term disruption of WM integrity. Diffusion changes suggest that myelin injury in WM is a hallmark of late-delayed radiation-induced brain injury.

Assessing cerebrovascular reactivity (CVR) in rhesus macaques (Macaca mulatta) using a hypercapnic challenge and pseudo-continuous arterial spin labeling (pCASL).

Cerebrovascular reactivity (CVR) is a measure of cerebral small vessels' ability to respond to changes in metabolic demand and can be quantified using magnetic resonance imaging (MRI) coupled with a vasoactive stimulus. Reduced CVR occurs with neurodegeneration and is associated with cognitive decline. While commonly measured in humans, few studies have evaluated CVR in animal models. Herein, we describe methods to induce hypercapnia in rhesus macaques (Macaca mulatta) under gas anesthesia to measure cerebral blood flow (CBF) and CVR using pseudo-continuous arterial spin labeling (pCASL). Fifteen (13 M, 2 F) adult rhesus macaques underwent pCASL imaging that included a baseline segment (100% O2) followed by a hypercapnic challenge (isoflurane anesthesia with 5% CO2, 95% O2 mixed gas). Relative hypercapnia was defined as an end-tidal CO2 (ETCO2) ≥5 mmHg above baseline ETCO2. The mean ETCO2 during the baseline segment of the pCASL sequence was 34 mmHg (range: 23-48 mmHg). During this segment, mean whole-brain CBF was 51.48 ml/100g/min (range: 21.47-77.23 ml/100g/min). Significant increases (p<0.0001) in ETCO2 were seen upon inspiration of the mixed gas (5% CO2, 95% O2). The mean increase in ETCO2 was 8.5 mmHg and corresponded with a mean increase in CBF of 37.1% (p<0.0001). The mean CVR measured was 4.3%/mmHg. No anesthetic complications occurred as a result of the CO2 challenge. Our methods were effective at inducing a state of relative hypercapnia that corresponds with a detectable increase in whole brain CBF using pCASL MRI. Using these methods, a CO2 challenge can be performed in conjunction with pCASL imaging to evaluate CBF and CVR in rhesus macaques. The measured CVR in rhesus macaques is comparable to human CVR highlighting the translational utility of rhesus macaques in neuroscience research. These methods present a feasible means to measure CVR in comparative models of neurodegeneration and cerebrovascular dysfunction.

Molecular characteristics of isthmus papillary thyroid cancers: Supporting evidence for unfavorable clinical behavior.

BACKGROUND: Previous studies demonstrate isthmus thyroid nodules are more likely to be malignant than lobar nodules. Additional data suggest that isthmus papillary thyroid cancers (PTCs) are more aggressive than lobar PTCs. We hypothesize that isthmus PTCs have a more unfavorable molecular profile. METHODS: The Cancer Genome Atlas (TCGA) database was queried to analyze clinical, mutation and gene expression data of isthmus PTCs compared to non-isthmus PTCs. RESULTS: We analyzed characteristics of 472 â€‹PTCs, including 19 isthmus PTCs. There were no significant differences between isthmus and non-isthmus PTC demographic and clinical variables or the frequency of RAS family, fusion driver, TERT, and tumor suppressor gene mutations. There was a trend towards increased BRAF mutations (68% vs 55%, p â€‹= â€‹0.28). A more aggressive gene expression profile was observed in isthmus PTC compared to lobar/multifocal PTC with differences in ERK score (19.4 vs 7.71, p â€‹< â€‹0.05) and TDS score (-0.58 vs 0.02, p â€‹< â€‹0.05). CONCLUSIONS: These results provide a possible molecular explanation for the more aggressive behavior reported in isthmus PTCs.

The TLR2/TLR6 ligand FSL-1 mitigates radiation-induced hematopoietic injury in mice and nonhuman primates.

Thrombocytopenia, hemorrhage, anemia, and infection are life-threatening issues following accidental or intentional radiation exposure. Since few therapeutics are available, safe and efficacious small molecules to mitigate radiation-induced injury need to be developed. Our previous study showed the synthetic TLR2/TLR6 ligand fibroblast stimulating lipopeptide (FSL-1) prolonged survival and provided MyD88-dependent mitigation of hematopoietic acute radiation syndrome (H-ARS) in mice. Although mice and humans differ in TLR number, expression, and function, nonhuman primate (NHP) TLRs are like those of humans; therefore, studying both animal models is critical for drug development. The objectives of this study were to determine the efficacy of FSL-1 on hematopoietic recovery in small and large animal models subjected to sublethal total body irradiation and investigate its mechanism of action. In mice, we demonstrate a lack of adverse effects, an easy route of delivery (subcutaneous) and efficacy in promoting hematopoietic progenitor cell proliferation by FSL-1. NHP given radiation, followed a day later with a single subcutaneous administration of FSL-1, displayed no adversity but showed elevated hematopoietic cells. Our analyses revealed that FSL-1 promoted red blood cell development and induced soluble effectors following radiation exposure. Cytologic analysis of bone marrow aspirates revealed a striking enhancement of mononuclear progenitor cells in FSL-1-treated NHP. Combining the efficacy of FSL-1 in promoting hematopoietic cell recovery with the lack of adverse effects induced by a single administration supports the application of FSL-1 as a viable countermeasure against H-ARS.

A New Method for Estimating Glomerular Filtration Rate in Rhesus Macaques (Macaca mulatta).

Late effects of total- or partial-body irradiation include chronic kidney injury (CKI), which increases morbidity and mortality. Glomerular filtration rate (GFR) is the gold standard measure of kidney function. Renal function markers, such as blood urea nitrogen (BUN) and serum creatinine (Cr), may not be higher than reference ranges until 50% or more of nephrons are affected. Currently available methods to measure GFR are difficult and expensive, requiring multiple blood draws or timed urine collections, but their use can provide a framework for the development of simpler GFR estimates. The measurement of iohexol clearance is a validated tool used to determine GFR in veterinary patients. In this study, we aimed to determine if the Schwartz formula as used in human pediatric medicine can estimate GFR in rhesus macaques. We hypothesized that iohexol-GFR would correlate with the Schwartz formula-estimated GFR (eGFR) in irradiated and non-irradiated rhesus macaques. Twelve rhesus macaques [age 5-14 years (mean 7 years); 5 females, 7 males] with a range of BUN levels were selected for comparison to 4 non-irradiated controls (2 females, 2 males). Irradiated animals were divided by BUN into 3 groups: BUN ≤20 mg/dL (n = 4), BUN >20-24 mg/dL (n = 4), and BUN ≥25 mg/dL (n = 4). Baseline serum chemistry and urinalysis were used to assess renal function. For measurement of GFR, macaques were maintained under general anesthesia and received an intravenous injection of iohexol (2 mL/kg, 300 mg I/mL). Whole blood was collected at 10, 30, 60 and 90 min post-iohexol injection. Plasma iohexol concentrations were determined by mass spectrometry. GFR was calculated from the peak iohexol concentration and trapezoidal area under the curve (tAUC). The iohexol-GFR significantly correlated with the Schwartz formula-eGFR. In macaques with renal irradiation doses below 6 Gy, GFR was higher for males than females. GFR was lower in macaques with renal irradiation doses greater than 6 Gy compared to macaques with renal doses less than 6 Gy. We conclude that use of the Schwartz formula can provide a rapid, non-invasive, cost-effective, and accurate estimation of GFR to aid in the clinical assessment of renal function in irradiated rhesus macaques.

Dose-Dependent Testicular Injury and Recovery after Total-Body Irradiation in Rhesus Monkeys.

Testicular injury is a well-documented acute effect of radiation exposure, though little is known about recovery years after irradiation, especially at higher doses. We examined the testes from 143 irradiated and control male rhesus monkeys, who were part of the Radiation Late Effects Cohort over a four-year period. Irradiated animals were exposed to doses ranging from 3.5 to 8.5 Gy of total-body irradiation. The testes were assessed using computed tomography (CT) volumetry, serum testosterone, and histology for deceased members of the cohort. Irradiated animals exhibited dose-dependent testicular atrophy as well as decreased serum testosterone during the winter breeding season when compared to age-matched unirradiated controls. No significant difference in summer testosterone levels was observed. Volumetric and histologic evidence of testicular recovery was present approximately three years postirradiation for animals who received ≤8 Gy. The study demonstrates dose-dependent testicular injury after total-body irradiation and provides evidence for volumetric and spermatogonial recovery even at lethal doses of total-body irradiation in rhesus monkeys.

Longitudinal Analysis of Leukocyte Total and Differential Count of Rhesus Macaques (Macaca mulatta) after Total-Body Irradiation.

Archival data of leukocyte count and the differentials obtained from control and irradiated Rhesus Macaques (Macaca mulatta) were statistically analyzed to understand the long-term effect of ionizing radiation exposure. Nine animals received total-body irradiation (TBI) of 7.2-8.4 Gy at 3-4 years old. Twelve animals served as age-matched controls with no radiation exposure. The complete blood cell count dataset was obtained during regular health exams every 2-6 months for 8 years from their age of 8 to 17 years old. Linear mixed models for leukocyte, neutrophil, lymphocyte, and monocyte counts and their percentages were successfully developed. Estimated marginal means calculated based on the models revealed statistically significant elevations in leukocyte and neutrophil counts and neutrophil percentages in irradiated animals compared to the controls. Lymphocyte percentage was significantly lower in irradiated animals. Longitudinal trends for both control and irradiated animals were consistent with expected trends of aging in hematopoiesis, which is skewed towards production of myeloid lineage cells such as neutrophils and monocytes rather than lymphoid cells. Longitudinal trends from irradiated animals suggested the age-related increase in neutrophils and decrease in lymphocytes were stronger than in the controls, although the difference did not reach statistical significance. The mechanism of the long-term effects in the hematopoietic system were not investigated. However, the results suggest ionizing radiation causes long-term effects on some of the factors implicated in hematopoietic aging, possibly inducing early-onset or accelerated aging in the hematopoietic system. Extended analysis with observations including before and after the follow-up period in this study will be beneficial to understand the timeline and features of the long-term response.

Measurement of renal cortical fibrosis by CT scan.

Rationale and objectives: The accurate, non-invasive, and rapid measurement of renal cortical fibrosis is needed for well-defined benchmarks of permanent injury and for use of anti-fibrotic agents. It is also needed for non-invasive and rapid assessment of the chronicity of human renal diseases. Materials and methods: We have used a non-human primate model of radiation nephropathy to develop a novel method of size-corrected CT imaging to quantify renal cortical fibrosis. Results: Our method has an area under the receiver operating curve of 0.96, which is superior to any other non-invasive method of measuring renal fibrosis. Conclusion: Our method is suitable for immediate translation to human clinical renal diseases.

Assessment of Blood Pressure in Irradiated Rhesus Macaques (Macaca mulatta).

There is increasing evidence that circulatory disease incidence and mortality is associated with radiation exposure. Wake Forest School of Medicine is home to a unique cohort of total-body irradiated macaques, some with evidence of vascular end-organ disease in the brain, kidney and heart. Because there is a link between high blood pressure and vascular disease in all these sites, we undertook a retrospective study to evaluate blood pressure and radiation in this cohort of animals. In this work, we utilized a cohort of nonhuman primates (rhesus macaques, Macaca mulatta) long-term survivors of high-dose total-body irradiation (1.1-8.5 Gy, N = 129) and controls (N = 37) to evaluate the effects of radiation on blood pressure and obesity. Subjects were between 3 and 22 years of age (median 9 years). Blood pressure (BP) was measured 1-14 years postirradiation (median 4 years). Subjects were sedated with a combination of ketamine HCl (15 mg/kg body weight, IM) and midazolam (0.1 mg/kg body weight, IM) and systolic, diastolic, and mean arterial pressures were measured using a high definition oscillometer. Obesity was defined by dual energy X-ray absorptiometry as a body fat percentage >35%. Statistical analysis of the collected data indicated significant increases in blood pressure with increasing age and obesity. However, radiation did not significantly alter blood pressure in irradiated animals relative to controls, radiation dose, or age of irradiation.

Local-Regional Recurrence After Neoadjuvant Endocrine Therapy: Data from ACOSOG Z1031 (Alliance), a Randomized Phase 2 Neoadjuvant Comparison Between Letrozole, Anastrozole, and Exemestane for Postmenopausal Women with Estrogen Receptor-Positive Clinical Stage 2 or 3 Breast Cancer.

BACKGROUND: The ACOSOG Z1031 trial addressed the ability of three neoadjuvant aromatase inhibitors (NAIs) to reduce residual disease (cohort A) and to assess whether switching to neoadjuvant chemotherapy (NCT) after 4 weeks of receiving NAI with Ki67 greater than 10% increases pathologic complete response (pCR) in postmenopausal women with estrogen receptor-enriched (Allred score 6-8) breast cancer (BC). METHODS: The study enrolled 622 women with clinical stage 2 or 3 estrogen receptor-positive (ER+) BC. Cohort A comprised 377 patients, and cohort B had 245 patients. The analysis cohort consisted of 509 patients after exclusion of patients who did not meet the trial eligibility criteria, switched to NCT or surgery due to 4-week Ki67 greater than 10%, or withdrew before surgery. Distribution of time to local-regional recurrence (LRR) was estimated using the competing-risk approach, in which distant recurrence and second primaries were considered to be competing-risk events. Patients who died without LRR, distant recurrence, or a second primary were censored at the last evaluation. RESULTS: Of the 509 patients, 342 (67.2%) had breast-conserving surgery (BCS). Of 221 patients thought to require mastectomy at presentation, 50% were able to have BCS. Five (1%) patients had no residual disease in the breast or nodes at surgery. Among 382 women alive at this writing, 90% have been followed longer than 5 years. The 5-year cumulative incidence rate for LRR is estimated to be 1.53% (95% confidence interval 0.7-3.0%). CONCLUSIONS: Rarely does NAI result in pCR for patients with stage 2 or 3 ER+ BC. However, a significant proportion will have downstaged to allow for BCS. Local-regional recurrence after surgery is uncommon (1.5% at 5 years), supporting the use of BCS after NAI.

Total thyroidectomy is more cost-effective than radioactive iodine as an alternative to antithyroid medication for Graves' disease.

BACKGROUND: Patients with Graves' disease treated with radioactive iodine report worse quality of life than those treated by thyroidectomy. However, radioactive iodine is often selected due to lower risk of complications and lower cost. The objective of this study was to estimate the cost-effectiveness of radioactive iodine versus total thyroidectomy for treatment of Graves' disease. METHODS: A Markov decision-analytic model was created to simulate clinical outcomes and costs of medication-refractory Graves' disease treated with radioactive iodine or total thyroidectomy. Complication rates and utilities were derived from published data. Costs were extracted from national Medicare reimbursement rates. We conducted 1-way, 2-way, and probabilistic sensitivity analyses to identify factors that influence cost-effectiveness and reflect uncertainty in model parameters. The willingness-to-pay threshold was set at $100,000/quality-adjusted life-years. RESULTS: Total thyroidectomy yielded 23.6 quality-adjusted life-years versus 20.9 quality-adjusted life-years for radioactive iodine. The incremental cost-effectiveness ratio was $2,982 per quality-adjusted life-years, indicating that surgery is highly cost-effective relative to radioactive iodine. Surgery was more cost effective than radioactive iodine in 88.2% of model simulations. Sensitivity analyses indicate that the model outcomes are driven predominantly by posttreatment quality of life, with contributing effects from rates of treatment complications and the impact of these complications on quality of life. CONCLUSION: For patients with Graves' disease who either cannot tolerate or are refractory to antithyroid drugs, thyroidectomy is more cost-effective than radioactive iodine. Future research should validate reported differences in quality of life between these 2 treatment modalities.

Quantitative Assessment and Comparative Analysis of Longitudinal Lung CT Scans of Chest-Irradiated Nonhuman Primates.

Computed tomography (CT) imaging has been used to diagnose radiation-induced lung injury for decades. However, histogram-based quantitative tools have rarely been applied to assess lung abnormality due to radiation-induced lung injury (RILI). Here, we used first-order summary statistics to derive and assess threshold measures extracted from whole lung histograms of CT radiodensity in rhesus macaques. For the present study, CT scans of animals exposed to 10 Gy of whole thorax irradiation were utilized from a previous study spanning 2-9 months postirradiation. These animals were grouped into survivors and non-survivors based on their clinical and experimental endpoints. We quantified the change in lung attenuation after irradiation relative to baseline using three density parameters; average lung density (ALD), percent change in hyper-dense lung volume (PCHV), hyperdense volume as a percent of total volume (PCHV/TV) at 2-month intervals and compared each parameter between the two irradiated groups (non-survivors and survivors). We also correlated our results with histological findings. All the three indices (ALD, PCHV, PCHV/TV) obtained from density histograms showed a significant increase in lung injury in non-survivors relative to survivors, with PCHV relatively more sensitive to detect early RILI changes. We observed a significant positive correlation between histologic pneumonitis scores and each of the three CT measurements, indicating that CT density is useful as a surrogate for histologic disease severity in RILI. CT-based three density parameters, ALD, PCHV, PCHV/TV, may serve as surrogates for likely histopathology patterns in future studies of RILI disease progression.

Long-Term Immunological Consequences of Radiation Exposure in a Diverse Cohort of Rhesus Macaques.

PURPOSE: The aim of this study was to develop an improved understanding of the delayed immunologic effects of acute total body irradiation (TBI) using a diverse cohort of nonhuman primates as a model for an irradiated human population. METHODS AND MATERIALS: Immune recovery was evaluated in 221 rhesus macaques either left unirradiated (n = 36) or previously irradiated (n = 185) at 1.1 to 8.5 Gy TBI (median, 6.5 Gy) when aged 2.1 to 15.5 years (median, 4.2 years). Blood was drawn annually for up to 5 years total between 0.5 and 14.3 years after exposure. Blood was analyzed by complete blood count, immunophenotyping of monocytes, dendritic cells (DC) and lymphocytes by flow cytometry, and signal joint T-cell receptor exclusion circle quantification in isolated peripheral blood CD4 and CD8 T cells. Animals were categorized by age, irradiation status, and time since irradiation. Sex-adjusted means of immune metrics were evaluated by generalized estimating equation models to identify cell populations altered by TBI. RESULTS: Overall, the differences between irradiated and nonirradiated animals were subtle and largely restricted to younger animals and select cell populations. Subsets of monocytes, DC, T cells, and B cells showed significant interaction effects between radiation dose and age after adjustment for sex. Irradiation at a young age caused transient increases in the percentage of peripheral blood myeloid DC and dose-dependent changes in monocyte balance for at least 5 years after TBI. TBI also led to a sustained decrease in the percentage of circulating memory B cells. Young irradiated animals exhibited statistically significant and prolonged disruption of the naïve/effector memory/central memory CD4 and CD8 T-cell equilibrium and exhibited a dose-dependent increase in thymopoiesis for 2 to 3 years after exposure. CONCLUSIONS: This study indicates TBI subtly but significantly alters the circulating proportions of cellular mediators of adaptive immune memory for several years after irradiation, especially in macaques under 5 years of age and those receiving a high dose of radiation.

Analysis of College of American Pathologists von Willebrand Factor Proficiency Testing Program.

Von Willebrand factor (VWF) level and/or function is altered in von Willebrand disease (VWD), the most common heritable bleeding disorder worldwide. Laboratory assessment of VWF is continually evolving. Historically, the primary method for the assessment of VWF platelet-binding activity was the ristocetin cofactor assay (VWF:RCo). Contemporary alternative measures of VWF platelet-binding activity include VWF:GPIbR (recombinant; using ristocetin), VWF:GPIbM (recombinant; gain-of-function mutant), and monoclonal antibody. Recently, the American Society of Hematology, International Society on Thrombosis and Haemostasis, National Hemophilia Foundation, and World Federation of Hemophilia collaboration issued guidelines recommending the use of newer assays of VWF platelet-binding activity (VWF: GPIbM, VWF: GPIbR) over VWF:RCo, given known limitations of the VWF:RCo assay. Despite this recommendation, the newer VWF:GPIbM and VWF:GPIbR assays are not United States Food and Drug Administration cleared, limiting their availability in the United States. We sought to assess assay utilization trends, agreement of VWF testing methods, and imprecision of VWF testing (based on assigned sample type) from the College of American Pathologists Proficiency Testing Surveys. The analysis confirms that, while VWF antigen testing has low imprecision, the various VWF activity assays have significant interassay variability, with VWF:RCo showing greater imprecision than the newer GPIb-binding assays. The overall trends in assay utilization reflect the barriers to complete compliance with modern VWD diagnostic guidelines in North America.