Distinct genomic and immunologic tumor evolution in germline TP53-driven breast cancers

Pathogenic germline TP53 alterations cause Li-Fraumeni Syndrome (LFS), and breast cancer is the most common cancer in LFS females. We performed first of its kind multimodal analysis of LFS breast cancer (LFS-BC) compared to sporadic premenopausal BC. Nearly all LFS-BC underwent biallelic loss of TP53 with no recurrent oncogenic variants except ERBB2 (HER2) amplification. Compared to sporadic BC, in situ and invasive LFS-BC exhibited a high burden of short amplified aneuploid segments (SAAS). Pro-apoptotic p53 target genes BAX and TP53I3 failed to be up-regulated in LFS-BC as was seen in sporadic BC compared to normal breast tissue. LFS-BC had lower CD8+ T-cell infiltration compared to sporadic BC yet higher levels of proliferating cytotoxic T-cells. Within LFS-BC, progression from in situ to invasive BC was marked by an increase in chromosomal instability with a decrease in proliferating cytotoxic T-cells. Our study uncovers critical events in mutant p53-driven tumorigenesis in breast tissue.

Atypical Adult-Onset Still's Disease Presenting With Seizures and Myocarditis Complicated by Macrophage Activation Syndrome

Adult-onset Still's disease (AOSD) is a rare multi-systemic inflammatory disorder characterized by high spiking fevers, nonpruritic, salmon-colored rash, and severe polyarthralgia. Laboratory features typically include elevation in white blood cells, liver enzymes, and ferritin. Central nervous system and cardiac involvements, particularly myocarditis, are rare. Macrophage activation syndrome (MAS) is a well-described complication of AOSD, leading to a high mortality rate. Herein, we describe a case of AOSD complicated by MAS in a 32-year-old male presenting with atypical clinical manifestations, including recurrent seizures, scaly, pruritic, and hyperpigmented rash, and right heart failure due to lymphocytic myocarditis. The patient exhibited a delayed onset of fever, leukocytosis, and transaminitis that initially deterred eligibility for Yamaguchi criteria for AOSD. Bone marrow and lymph node biopsies did not show malignancy, infection, or hemophagocytosis. However, soluble interleukin-2 receptor alpha or soluble CD-25 was elevated. The patient experienced significant improvement on combination therapy of anakinra, methotrexate, and stress-dose steroids. HScore was later indicative of a high probability for MAS. Outpatient management involved prednisone, cyclosporine, and canakinumab for MAS. Seizure and myocarditis are possible presenting features of atypical AOSD. Early recognition of non-criteria AOSD and MAS and prompt initiation of therapy may prevent mortality.

Rates of Intervention and Cancer Detection on Initial versus Subsequent Whole-body MRI Screening in Li-Fraumeni Syndrome

Li-Fraumeni Syndrome (LFS) is a hereditary cancer predisposition syndrome with up to 90% lifetime cancer risk. Cancer screening, including annual whole-body MRI (WB-MRI), is recommended due to known survival advantage, with cancer detection rate of 7% on initial screening. Intervention and cancer detection rates on subsequent screenings are unknown. Clinical data for pediatric and adult patients with LFS (n = 182) were reviewed, including instances of WB-MRI screening and interventions based on screening results. For each WB-MRI screening, interventions including biopsy and secondary imaging, as well as rate of cancer diagnosis, were analyzed comparing initial versus subsequent WB-MRI. Of the total cohort (n = 182), we identified 68 adult patients and 50 pediatric patients who had undergone at least two WB-MRI screenings, with a mean of 3.8 ± 1.9 (adults) and 4.0 ± 2.1 (pediatric) screenings. Findings on initial screening led to an imaging or invasive intervention in 38% of adults and 20% of children. On follow up, overall intervention rates were lower for adults (19%, P = 0.0026) and stable for children (19%, P = NS). Thirteen cancers were detected overall (7% of adult and 14% of pediatric scans), on both initial (pediatric: 4%, adult: 3%) and subsequent (pediatric: 10%, adult: 6%) screenings. Rates of intervention after WB-MRI screening decreased significantly in adults between first and subsequent exams and remained stable in pediatric patients. Cancer detection rates were similar on screening (3%-4% initial, 6%-10% subsequent) for both children and adults. These findings provide important data for counseling patients with LFS about screening outcomes.

PREVENTION RELEVANCE

The cancer detection rate, burden of recommended interventions, and rate of false-positive findings found on subsequent WB-MRI screenings in patients with LFS are not well understood. Our findings suggest that annual WB-MRI screening has clinical utility and likely does not result in an unnecessary invasive intervention burden for patients.

Biallelic BRCA Loss and Homologous Recombination Deficiency in Nonbreast/Ovarian Tumors in Germline BRCA1/2 Carriers

PURPOSE

Breast and ovarian tumors in germline BRCA1/2 carriers undergo allele-specific loss of heterozygosity, resulting in homologous recombination deficiency (HRD) and sensitivity to poly-ADP-ribose polymerase (PARP) inhibitors. This study investigated whether biallelic loss and HRD also occur in primary nonbreast/ovarian tumors that arise in germline BRCA1/2 carriers.

METHODS

A clinically ascertained cohort of BRCA1/2 carriers with a primary nonbreast/ovarian cancer was identified, including canonical (prostate and pancreatic cancers) and noncanonical (all other) tumor types. Whole-exome sequencing or clinical sequencing results (n = 45) were analyzed. A pan-cancer analysis of nonbreast/ovarian primary tumors from germline BRCA1/2 carriers from The Cancer Genome Atlas (TCGA, n = 73) was used as a validation cohort.

RESULTS

Ages of nonbreast/ovarian cancer diagnosis in germline BRCA1/2 carriers were similar to controls for the majority of cancer types. Nine of 45 (20%) primary nonbreast/ovarian tumors from germline BRCA1/2 carriers had biallelic loss of BRCA1/2 in the clinical cohort, and 23 of 73 (32%) in the TCGA cohort. In the combined cohort, 35% and 27% of primary canonical and noncanonical BRCA tumor types, respectively, had biallelic loss. High HRD scores (HRDex > 42) were detected in 81% of tumors with biallelic BRCA loss compared with 22% (P < .001) of tumors without biallelic BRCA loss. No differences in genomic profile, including mutational signatures, mutation spectrum, tumor mutational burden, or microsatellite instability, were found in primary nonbreast/ovarian tumors with or without biallelic BRCA1/2 loss.

CONCLUSION

A proportion of noncanonical primary tumors have biallelic loss and evidence of HRD. Our data suggest that assessment of biallelic loss and HRD could supplement identification of germline BRCA1/2 mutations in selection of patients for platinum or PARP inhibitor therapy.

Demonstration of a population-based HCV serosurvey in Ho Chi Minh City, Viet Nam: Establishing baseline prevalence of and continuum of care for HCV micro-elimination by 2030

BACKGROUND

A baseline of hepatitis C virus (HCV) burden and other HCV epidemiological profiles is necessary for HCV micro-elimination in Ho Chi Minh City (HCMC), Viet Nam. This study aimed to determine HCV exposure and prevalence of HCV viremia as well as the proportion of HCV testing and treatment uptake among participants.

METHODS

From 2019 to 2020, the probability proportionate to size sampling method was deployed to representatively invite approximately 20,000 adults (18 or older) throughout HCMC to free screening and linkage to care for HCV.

FINDINGS

In HCMC, the weighted prevalence of anti-HCV was 1·3% (95% CI, 1·1%-1·6%). Individuals born from 1945 to 1964 had the anti-HCV prevalence of 3·6% (95% CI, 3·0%-4·2%) and represented 40·4% of all HCV cases. There were wide variations in anti-HCV prevalence in HCMC, including variations between districts, risk factors, and socioeconomic statuses. A baseline HCV continuum of care for the city demonstrated that only 28·5% (85/298, 95%CI 23·4-33·7%) of persons with anti-HCV (+) were aware of their HCV status, with 77.6% (66/85, 95%CI 68·8-86·5%) diagnosing HCV incidentally, 82·7% (62/75, 95%CI 74·1-91·2%) initiating anti-HCV therapy, and 53.6% (30/56, 95%CI 40·5-66·6%) achieving HCV cures.

INTERPRETATION

There remains a considerable disease burden of HCV in HCMC of which a significant proportion was in the age group born between 1945 to 1964. Additionally, there were significant gaps in HCV awareness, screening, and access to care in the community in Viet Nam. Thus, future interventions must have pragmatic targets, be tailored to the local needs, and emphasise screening.

FUNDING

This work was supported by investigator-sponsored research grants from Gilead Sciences Inc. (Grant No: IN-US-987-5382); Roche Diagnostic International Ltd. (Grant No. SUB-000196); and in-kind donations from Abbott Diagnostic Viet Nam; Hepatitis B Foundation; Medic Medical Center, Viet Nam; Johns Hopkins University School of Medicine's Center of Excellence for Liver Disease in Viet Nam; and the Board of Directors, Viet Nam Viral Hepatitis Alliance (V-VHA).

Potential biomarkers of endocrine and habitat disruption identified via RNA-Seq in Salvelinus fontinalis with proximity to fracking operations in Pennsylvania headwater stream ecosystems

Unconventional natural gas development (fracking) has been a rapidly expanding technique used for the extraction of natural gas from the Marcellus Shale formation in Pennsylvania. There remains a knowledge gap regarding the ecological impacts of fracking, especially regarding the long-term health of native Brook trout (Salvelinus fontinalis) populations. During the summer of 2015, Brook trout were sampled from twelve streams located in forested, northwestern Pennsylvania in order to evaluate the impacts of fracking on Brook trout. Four stream sites were undisturbed (no fracking activity), three had a developed well pad without fracking activity, and five had active fracking with natural gas production. Liver tissue was isolated from two to five fish per stream and underwent RNA-Seq analysis to identify differentially expressed genes between ecosystems with differing fracking status. Data were analyzed individually and with samples pooled within-stream to account for hierarchical data structure and variation in sample coverage within streams. Differentially expressed and differentially alternatively spliced genes had functions related to lipid and steroid metabolism, mRNA processing, RNA polymerase and protein regulation. Unique to our study, genes related to xenobiotic and stress responses were found as well as potential markers for endocrine disruption and saline adaptation that were identified in watersheds with active fracking activity. These results support the utility of RNA-Seq to assess trout health and suggest detrimental impacts of fracking on sensitive trout populations.

Abstract 2237: Rates of intervention after initial versus subsequent whole-body MRI screening in Li-Fraumeni Syndrome

Background: Yearly whole-body MRI is recommended for cancer screening in patients with the rare high risk cancer predisposition syndrome, Li-Fraumeni syndrome (LFS). This is based on data from multiple studies demonstrating an approximately 7% cancer detection rate on baseline screening. However, the rate of actionable findings and malignancies on initial versus subsequent screenings has yet to be compared in a patient cohort.

Patients and Methods: We identified 68 adult LFS patients in a single institutional cohort that received more than one full body MRI (including brain MRI). For each screening instance, findings and subsequent recommended interventions (immediate and short-term imaging, biopsy, and/or surgery) were recorded. Invasive interventions (biopsy and/or surgery) were denoted with free text describing pathology results. We analyzed findings on initial versus subsequent scans.

Results: There were 258 instances of whole-body MRI screenings performed in 68 patients (28% male, 72% female) in the cohort. The mean number of screenings per patient analyzed was 3.8±1.9 over 3.3±2.4 years. Among 68 initial screenings, 26 (38.2%) required follow-up imaging or invasive intervention. Among 190 subsequent screenings, the follow-up intervention rate was significantly lower (n=36, 18.9%, p=0.0026). Eleven screenings (5.8%) required invasive follow-up (biopsy or surgery); two (3% of patients) were from an initial screening and nine (13% of patients) were from a subsequent screening. From these interventions, we identified six total cancers in five patients amongst the cohort (7% of patients), with two cancers (3% of patients) being identified on the first screening and four (6% of patients) being identified on a subsequent screening.

Conclusion: Cancer detection rates were similar between initial and subsequent whole-body MRI screenings in LFS patients. Follow-up interventions decreased significantly on subsequent screenings compared to the initial screen. These findings may be useful in counseling of LFS patients initiating a screening program. Limitations of this study include lack of inclusion of other screening modalities in the analysis, short follow-up duration, and loss to follow-up. Further studies involving a larger cohort with longer-term follow-up are needed to fully determine the impact of long-term whole-body MRI screening in LFS.

Citation Format: Yun K. Du, Conrad Fernandes, Anh N. Le, Madeline Good, Miche Duvall, Sarah Jennings, Jacquelyn Powers, Kristen Zelley, Bryson W. Katona, Suzanne P. MacFarland, Kara N. Maxwell. Rates of intervention after initial versus subsequent whole-body MRI screening in Li-Fraumeni Syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2237.

SARS-CoV-2 Seropositivity and Seroconversion in Patients Undergoing Active Cancer-Directed Therapy

PURPOSE

Multiple studies have demonstrated the negative impact of cancer care delays during the COVID-19 pandemic, and transmission mitigation techniques are imperative for continued cancer care delivery. We aimed to gauge the effectiveness of these measures at the University of Pennsylvania.

METHODS

We conducted a longitudinal study of SARS-CoV-2 antibody seropositivity and seroconversion in patients presenting to infusion centers for cancer-directed therapy between May 21, 2020, and October 8, 2020. Participants completed questionnaires and had up to five serial blood collections.

RESULTS

Of 124 enrolled patients, only two (1.6%) had detectable SARS-CoV-2 antibodies on initial blood draw, and no initially seronegative patients developed newly detectable antibodies on subsequent blood draw(s), corresponding to a seroconversion rate of 0% (95% CI, 0.0 TO 4.1%) over 14.8 person-years of follow up, with a median of 13 health care visits per patient.

CONCLUSION

These results suggest that patients with cancer receiving in-person care at a facility with aggressive mitigation efforts have an extremely low likelihood of COVID-19 infection.

Association of Inherited Mutations in DNA Repair Genes with Localized Prostate Cancer

Background:

Identification of germline mutations in DNA repair genes has significant implications for the personalized treatment of individuals with prostate cancer (PrCa).

Objective:

To determine DNA repair genes associated with localized PrCa in a diverse academic biobank and to determine genetic testing burden.

Design, setting, and participants:

A cross-sectional study of 2391 localized PrCa patients was carried out.

Outcome measurements and statistical analysis:

Genetic ancestry and mutation rates (excluding somatic interference) in 17 DNA repair genes were determined in 1588 localized PrCa patients and 3273 cancer-free males. Burden testing within individuals of genetically determined European (EUR) and African (AFR) ancestry was performed between biobank PrCa cases and cancer-free biobank and gnomAD males.

Results and limitations:

AFR individuals with localized PrCa had lower DNA repair gene mutation rates than EUR individuals (1.4% vs 4.0%, p = 0.02). Mutation rates in localized PrCa patients were similar to those in biobank and gnomAD controls (EUR: 4.0% vs 2.8%, p = 0.15, vs 3.1%, p = 0.04; AFR: 1.4% vs 1.8%, p = 0.8, vs 2.1%, p = 0.5). Gene-based rare variant association testing revealed that only BRCA2 mutations were significantly enriched compared with gnomAD controls of EUR ancestry (1.0% vs 0.28%, p = 0.03). Of the participants, 21% and 11% met high-risk and very-high-risk criteria; of them, 3.7% and 6.2% had any germline genetic mutation and 1.0% and 2.5% had a BRCA2 mutation, respectively. Limitations of this study include an analysis of a relatively small, single-institution cohort.

Conclusions:

DNA repair gene germline mutation rates are low in an academic biobank cohort of localized PrCa patients, particularly among individuals of AFR genetic ancestry. Mutation rates in genes with published evidence of association with PrCa exceed 2.5% only in high-risk, very-high-risk localized, and node-positive PrCa patients. These findings highlight the importance of risk stratification in localized PrCa patients to identify appropriate patients for germline genetic testing.

Patient summary:

In the majority of patients who develop localized prostate cancer, germline genetic testing is unlikely to reveal an inherited DNA repair mutation, regardless of race. High-risk features increase the possibility of a germline DNA repair mutation.

Rates of COVID-19-Related Outcomes in Cancer Compared With Noncancer Patients

Cancer patients are a vulnerable population postulated to be at higher risk for severe coronavirus disease 2019 (COVID-19) infection. Increased COVID-19 morbidity and mortality in cancer patients may be attributable to age, comorbidities, smoking, health care exposure, and cancer treatments, and partially to the cancer itself. Most studies to date have focused on hospitalized patients with severe COVID-19, thereby limiting the generalizability and interpretability of the association between cancer and COVID-19 severity. We compared outcomes of SARS-CoV-2 infection in 323 patients enrolled in a population-based study before the pandemic (n = 67 cancer patients; n = 256 noncancer patients). After adjusting for demographics, smoking status, and comorbidities, a diagnosis of cancer was independently associated with higher odds of hospitalization (odds ratio = 2.16, 95% confidence interval = 1.12 to 4.18) and 30-day mortality (odds ratio = 5.67, 95% confidence interval = 1.49 to 21.59). These associations were primarily driven by patients with active cancer. These results emphasize the critical importance of preventing SARS-CoV-2 exposure and mitigating infection in cancer patients.

SARS-CoV-2 seropositivity and seroconversion in patients undergoing active cancer-directed therapy

Multiple studies have demonstrated the negative impact of cancer care delays during the COVID-19 pandemic, and transmission mitigation techniques are imperative for continued cancer care delivery. To gauge the effectiveness of these measures at the University of Pennsylvania, we conducted a longitudinal study of SARS-CoV-2 antibody seropositivity and seroconversion in patients presenting to infusion centers for cancer-directed therapy between 5/21/2020 and 10/8/2020. Participants completed questionnaires and had up to five serial blood collections. Of 124 enrolled patients, only two (1.6%) had detectable SARS-CoV-2 antibodies on initial blood draw, and no initially seronegative patients developed newly detectable antibodies on subsequent blood draw(s), corresponding to a seroconversion rate of 0% (95%CI 0.0-4.1%) over 14.8 person-years of follow up, with a median of 13 healthcare visits per patient. These results suggest that cancer patients receiving in-person care at a facility with aggressive mitigation efforts have an extremely low likelihood of COVID-19 infection.

Upper Gastrointestinal Cancer Risk and Surveillance Outcomes in Li-Fraumeni Syndrome

INTRODUCTION

To assess the upper gastrointestinal (UGI) cancer risk and surveillance outcomes in Li-Fraumeni syndrome (LFS).

METHODS

Analysis of the International Agency for Research on Cancer database and a single-center adult LFS cohort.

RESULTS

UGI cancer was present in 7.2% of families and 3.9% of individuals with a pathogenic/likely pathogenic TP53 mutation in International Agency for Research on Cancer; 29% occurred before age 30. Our institutional cohort had 35 individuals (31% of the LFS cohort) with 48 cumulative upper endoscopies; 3 (8.5%) individuals had concerning UGI findings.

DISCUSSION

UGI cancer is observed in LFS. Upper endoscopy should be part of a comprehensive LFS surveillance program.

Rates of COVID-19-related Outcomes in Cancer compared to non-Cancer Patients

Cancer patients are a vulnerable population postulated to be at higher risk for severe COVID-19 infection. Increased COVID-19 morbidity and mortality in cancer patients may be attributable to age, comorbidities, smoking, healthcare exposure, and cancer treatments, and partially to the cancer itself. Most studies to date have focused on hospitalized patients with severe COVID-19, thereby limiting the generalizability and interpretability of the association between cancer and COVID-19 severity. We compared outcomes of SARS-CoV-2 infection in 323 patients enrolled prior to the pandemic in a large academic biobank (n=67 cancer patients and n=256 non-cancer patients). After adjusting for demographics, smoking status, and comorbidities, a diagnosis of cancer was independently associated with higher odds of hospitalization (OR 2.16, 95% CI 1.12-4.18) and 30-day mortality (OR 5.67, CI 1.49-21.59). These associations were primarily driven by patients with active cancer. These results emphasize the critical importance of preventing SARS-CoV-2 exposure and mitigating infection in cancer patients.

A Rare TP53 Mutation Predominant in Ashkenazi Jews Confers Risk of Multiple Cancers

Germline mutations in TP53 cause a rare high penetrance cancer syndrome, Li-Fraumeni syndrome (LFS). Here, we identified a rare TP53 tetramerization domain missense mutation, c.1000G>C;p.G334R, in a family with multiple late-onset LFS-spectrum cancers. Twenty additional c.1000G>C probands and one c.1000G>A proband were identified, and available tumors showed biallelic somatic inactivation of TP53. The majority of families were of Ashkenazi Jewish descent, and the TP53 c.1000G>C allele was found on a commonly inherited chromosome 17p13.1 haplotype. Transient transfection of the p.G334R allele conferred a mild defect in colony suppression assays. Lymphoblastoid cell lines from the index family in comparison with TP53 normal lines showed that although classical p53 target gene activation was maintained, a subset of p53 target genes (including PCLO, PLTP, PLXNB3, and LCN15) showed defective transactivation when treated with Nutlin-3a. Structural analysis demonstrated thermal instability of the G334R-mutant tetramer, and the G334R-mutant protein showed increased preponderance of mutant conformation. Clinical case review in comparison with classic LFS cohorts demonstrated similar rates of pediatric adrenocortical tumors and other LFS component cancers, but the latter at significantly later ages of onset. Our data show that TP53 c.1000G>C;p.G334R is found predominantly in Ashkenazi Jewish individuals, causes a mild defect in p53 function, and leads to low penetrance LFS. SIGNIFICANCE: TP53 c.1000C>G;p.G334R is a pathogenic, Ashkenazi Jewish-predominant mutation associated with a familial multiple cancer syndrome in which carriers should undergo screening and preventive measures to reduce cancer risk.

Abstract P4-12-33: Frequency of radiation-induced malignancies post-adjuvant radiotherapy for breast cancer in patients with Li-Fraumeni syndrome

Background. Women with Li-Fraumeni syndrome (LFS), a cancer predisposition syndrome caused by germline mutations in TP53, have an over 50% risk of developing breast cancer (BC) by age 70. Providers often avoid adjuvant radiotherapy to treat BC in LFS patients due to a reported high risk of radiation-induced malignancies of over 30%. We aimed to investigate the characteristics of LFS-associated BC and the risk of subsequent malignancy in BC patients with LFS following adjuvant radiotherapy.

Methods. A single institution retrospective chart review was conducted for female BC patients with a confirmed germline TP53 mutation. Statistical analyses were performed to compare the frequency of radiation-induced malignancies in LFS patients to non-LFS BC cases reported in the Penn Medicine Cancer Registry (PMCR) (n=6607 patients total, 3863 who received radiation).

Results. Among 95 patients with LFS, we identified 51 female BC patients with 74 primary BC diagnoses. Of 51 patients, 57% had a history of BC only, and 25% had BC as their presenting diagnosis of LFS. LFS-associated BCs were predominantly invasive ductal carcinoma (48%) and HER2+ (58%). We analyzed 20 LFS BC patients who underwent adjuvant radiotherapy with an average follow up of 11.1 (2-20) years. Of 18 patients who received radiation in a curative setting, one (6%) patient developed thyroid cancer and one (6%) patient developed sarcoma in the radiation field. The incidence of thyroid cancer did not significantly differ between LFS-associated and non-LFS BCs. The incidence of radiation-induced sarcoma in patients with LFS is significantly higher than in non-LFS BC patients (0.03%, p=0.01).

Conclusion. We found a 6% (one in 18 patients) risk of radiation-induced sarcoma in LFS BC patients, lower than the previously reported rate of 33%. Adjuvant radiotherapy should be considered in LFS BC patients when the potential risk for locoregional recurrence (LRR) or the mortality benefit to radiation is greater than 6%.

Citation Format: Anh N Le, Jacquelyn Powers, Kristin Zelley, Angela Bradbury, Payal Shah, Gary Freedman, Katherine Nathanson, Susan M Domchek, Suzanne P MacFarland, Kara N Maxwell. Frequency of radiation-induced malignancies post-adjuvant radiotherapy for breast cancer in patients with Li-Fraumeni syndrome [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-12-33.

Simulated Soil Organic Carbon Changes in Maryland Are Affected by Tillage, Climate Change, and Crop Yield

The impact of climate change on soil organic C (SOC) stocks in no-till (NT) and conventionally tilled (CT) agricultural systems is poorly understood. The objective of this study was to simulate the impact of projected climate change on SOC to 50-cm soil depth for grain cropping systems in the southern Mid-Atlantic region of the United States. We used SOC and other data from the long-term Farming Systems Project in Beltsville, MD, and CQESTR, a process-based soil C model, to predict the impact of cropping systems and climate (air temperature and precipitation) on SOC for a 40-yr period (2012-2052). Since future crop yields are uncertain, we simulated five scenarios with differing yield levels (crop yields from 1996-2014, and at 10 or 30% greater or lesser than these yields). Without change in climate or crop yields (baseline conditions) CQESTR predicted an increase in SOC of 0.014 and 0.021 Mg ha yr in CT and NT, respectively. Predicted climate change alone resulted in an SOC increase of only 0.002 Mg ha yr in NT and a decrease of 0.017 Mg ha yr in CT. Crop yield declines of 10 and 30% led to SOC decreases between 2 and 8% compared with 2012 levels. Increasing crop yield by 10 and 30% was sufficient to raise SOC 2 and 7%, respectively, above the climate-only scenario under both CT and NT between 2012 and 2052. Results indicate that under these simulated conditions, the negative impact of climate change on SOC levels could be mitigated by crop yield increases.

Unexpected lung lesions in high resolution computed tomography (HRTC) among patients with advanced HIV disease

The present pilot study was undertaken to characterize the frequency of lung lesions in asymptomatic human deficiency virus (HIV) infected individuals with advanced HIV disease. Thirty two consecutive HIV+ homosexual males assessed for initiation of Pneumocystis carinii pneumonia (PCP) prophylaxis, were prospectively studied. All patients underwent a complete medical history, physical examination, pulmonary function tests and high resolution computed tomography (HRCT). HRCT scans were read by a single radiologist, who was blind as to the clinical status of the patient. Unexpected HRCT scan lesions were found in 60% of patients. There were no statistically significant differences between patients with normal and abnormal HRCT with respect to age, height, weight, CD4+ count, smoking history, serum albumin, alpha 1-antitrypsin level or body mass index. Forced vital capacity (FVC) (% of predicted) and peak expiratory flow rate (PEFR) (% pred) were not significantly different between groups. For patients with normal and abnormal HRCT forced expiratory volume in one second (FEV1) (% pred) was 99 +/- 12 vs 92 +/- 16, FEV1/FVC was 82 +/- 5 vs 76 +/- 9, and forced mid-expiratory flow (FEF25-75) (% pred) was 100 +/- 24 vs 77 +/- 27, respectively. There were no statistically significant differences between patients presenting with destructive versus nondestructive lung HRCT lesions. Our results demonstrate that as many as 60% of HIV-infected patients have unexpected abnormalities on HRCT at the time of starting PCP prophylaxis. We speculate that these lesions may contribute to the high frequency of spontaneous pneumothoraces previously reported in this patient population.

Very low-density lipoprotein metabolism in an unusual case of lipoatrophic diabetes

Complete acquired lipoatrophic diabetes (LD) is characterized by nonketotic insulin-resistant diabetes, elevated very low-density lipoprotein (VLDL) triglyceride (TG) levels, and absent subcutaneous fat. We studied a young child in whom LD atypically developed after the onset of type 1 diabetes mellitus. On uncontrolled home diet the patient had triglyceride levels over 1,000 mg/dL on multiple occasions. In order to demonstrate the effects of caloric and dietary-fat restriction on VLDL metabolism, 3H-glycerol and autologous 125I-VLDL were used to quantitate the turnover of VLDL-TG and VLDL-apolipoprotein B (apo B) during two periods of caloric restriction. Consumption of a 900-kcal 40-g fat diet resulted in a plasma triglyceride level of 1383 mg/dL (ten-fold elevation). This hypertriglyceridemia was associated with markedly increased production rates of both VLDL-TG (73.7 mg/kg/h) and VLDL-apo B (126.9 mg/kg/d). Consumption of a 900-kcal 25-g fat diet resulted in a plasma TG level of 663 mg/dL. This reduction in plasma TG was associated with a 40% decrease in VLDL-TG production rate (PR) (45.1 mg/kg/h). There was no change in the production rate (PR) of VLDL-apo B. The hypertriglyceridemia in this patient was due to marked over production of VLDL. Furthermore, the studies demonstrate: (1) the independent benefits of caloric and dietary-fat restriction in the treatment of LD, and (2) that fat restriction lowered plasma triglyceride by its effect on the VLDL-TG production rate.