"Moderately Hypofractionated" Radiotherapy with a Simultaneously Integrated Boost for Synchronous Treatment of Prostate and Anorectal Cancer

PURPOSE/OBJECTIVE(S)

Data suggest safety and efficacy of 1.8-2.0 Gy per day radiotherapy (RT) with sequential boost regimens for patients with synchronous prostate and anorectal cancers. Emergence of 25-28 fraction (fx) prostate cancer RT regimens has enabled simultaneously integrated boost techniques to treat the prostate and anorectum (HypoRT), but limited reports exist to support the safety or efficacy of this approach. We aimed to assess oncologic outcomes and patient-reported outcomes (PRO)- and physician-reported adverse effects (AEs) of HypoRT for patients with synchronous prostate and anorectal cancers.

MATERIALS/METHODS

This was a retrospective cohort study of patients synchronously diagnosed with prostate and rectal cancer or anal canal squamous cell carcinoma (ASCC) treated with a HypoRT technique and concurrent chemotherapy between 2014-2022. Outcomes included prostate cancer biochemical recurrence (BCR), anorectal cancer recurrence, progression-free (PFS) and overall survival (OS). Acute and late gastrointestinal (GI) and genitourinary (GU) AEs and PRO were prospectively collected using common terminology criteria for AEs (CTCAE) and PRO-CTCAE.

RESULTS

Twelve patients were included. Patients had ECOG 0-1; median age was 71 years (51-82). Rectal cancer (n = 11) characteristics included T3 (91%), N1-2 (73%), M0 (73%); 3 had M1a disease suitable for curative-intent treatment. One patient had T2N1M0 ASCC. Prostate cancer risk groups included low (9%), intermediate (45%), and high/very high risk (46%). HypoRT included 45-50 and 67.5 Gy in 25 fx (33%), 46.8-52 and 70.2 Gy in 26 fx (17%), and 44.8-56 and 70 Gy in 28 fx (50%), to the pelvis-anorectum and prostate. Patients with rectal cancer received concurrent capecitabine. Nine (82%) patients with rectal cancer had surgical resection; 1 was R1. The patient with ASCC received concurrent 5-fluorouracil and mitomycin C. Six patients (50%) received androgen suppression. All patients completed treatment successfully but 1 patient with rectal cancer did require hospitalization with treatment break due to GI AEs. Median follow was 60 months (13-103). Oncologic outcomes and AEs are in the table. No patient experienced prostate cancer BCR or ASCC progression. Four of 11 patients with rectal cancer progressed including 3 distant metastases, each amongst initial M1a patients, and 1 local-regrowth in a patient managed non-operatively.

CONCLUSION

HypoRT can effectively be utilized for patients with synchronous prostate and anorectal cancer. Physician assessed AEs compared favorably with prior data, however, further work is needed to understand differences in physician and patient experience. HypoRT may serve as another suitable option in the management of this complex clinical scenario.

Patient-Specific 3D CT Images Reconstruction from 2D KV Images Via Vision Transformer-Based Deep-Learning

PURPOSE/OBJECTIVE(S)

In some proton therapy facilities, patient alignment relies on two 2D orthogonal kV images, taken at fixed, oblique angles, as no 3D on-the-bed-imaging is available. The visibility of the tumor in kV images is limited since the patient's 3D anatomy is projected onto a 2D plane, especially when the tumor is behind a high-density structure such as bone. This can lead to a large patient setup error. A solution to this problem is to reconstruct the 3D CT image from the kV images obtained in the treatment position.

MATERIALS/METHODS

An asymmetric autoencoder-like network built with vision-transformer blocks was developed. The data was collected from a head and neck patient: 2 orthogonal kV images (1024X1024 voxels), 1 3D CT with padding (512X512X512) acquired from the in-room CT-on-rails before kVs were taken and 2 digitally-reconstructed-radiograph (DRR) images (512X512) based on the CT. We resampled kV images every 8 voxels and DRR and CT every 4 voxels, thus formed a dataset consisting of 262,144 samples, in which the images had a dimension of 128 for each direction. The value of each voxel in CT was normalized to range 0-1 with a uniform shift of 1000 and a denominator of 4000. For kV and DRR, we ranked all voxels value in an ascending order and normalized the values of the first 80% voxels to range 0-0.8 and the rest to range 0.8-1, thus yielding a quasi-Gaussian distribution, which was favorable by the deep neural networks. We further cropped kV and DRR images with a self-supervised bitmap based on the voxels' gradients. In training, both kV and DRR were utilized, and the encoder was encouraged to learn the same feature maps for kV images and its corresponding DRR images with mean-absolute-error (MAE) as the similarity loss. Then the decoder would reconstruct the 3D CT image from the feature maps of the kV images with the CT-on-rails as ground-truth (gCT) and MAE as the reconstruction loss. In testing, only independent kV images were used. The full-size synthetic CT (sCT) was achieved by concatenating the sCTs generated by the model according to their spatial information. The image quality of the sCT was evaluated using MAE and per-voxel-absolute-CT-number-difference volume histogram (CDVH). The proposed network was implemented with PyTorch deep learning library and both distributed data parallel (DDP) and automatic mixed precision (AMP) were applied to saving memory and accelerating the training speed. We used the AdamW optimizer with β1 = 0.9 and β2 = 0.999 and a cosine annealing learning rate scheduler with an initial learning of 1e-7 and 20 warm-up epochs.

RESULTS

The model achieved a MAE of <40HU and the CDVH showed that <5% of the voxels had a per-voxel-absolute-CT-number-difference larger than 185HU. The profile of a typical gCT slice and its corresponding sCT slice exhibited a high agreement, indicating the high similarity between the gCT and sCT.

CONCLUSION

A patient-specific vision-transformer-based network was developed and shown to be accurate and efficient to reconstruct 3D CT images from kV images.

Physician and Patient-Reported Outcomes of a Phase III Trial of Ultra-Hypofractionated vs. Moderate Hypofractionated Radiotherapy to the Whole Breast after Breast-Conserving Surgery

PURPOSE/OBJECTIVE(S)

To report a final analysis evaluating physician and patient-reported outcomes of early breast cancer patients receiving moderate hypofractionation or ultra-hypofractionated whole breast radiotherapy (RT).

MATERIALS/METHODS

Between April 4, 2018, and February 11, 2020, patients with localized breast cancer (T1-T3, N0-N1, and M0) managed with breast-conserving surgery (BCS) were enrolled. Patients were randomized to receive whole breast RT with moderate hypofractionation to 40 Gy in 15 fractions (Arm A) or ultra-hypofractionation to 25 Gy in 5 fractions (Arm B). An optional concurrent integrated boost to 48 Gy on Arm A or 30 Gy on Arm B was allowed. Early toxicity (<3 months), late toxicity (> 3 months), quality of life (QOL), cosmesis, Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), and deterioration of cosmesis were analyzed.

RESULTS

One hundred and seven patients were randomized to moderate hypofractionation (n = 54) or ultra-hypofractionation (n = 53). With a median follow-up of 36 months, no significant differences in patient characteristics were noted between the two arms. There were no patients with a grade ≥3 or higher toxicity. Grade 2 toxicities were 7.4% in Arm A and 7.5% in Arm B, and primarily consisted of radiation dermatitis (6 patients), fibrosis (1 patient) and lymphedema (1 patient). The average Harvard Cosmesis score and overall QoL were similar between arms at all time points, with no patients developing cosmetic deterioration. Patient-reported moderate to severe radiation skin burns were more commonly reported in Arm A (21.05%) vs. Arm B (6.25%) at the end of treatment (EOT) (p = 0.078). At EOT, patients receiving moderate hypofractionation had higher mean toxicity scores in breast tenderness (2.66 vs. 1.5, p = 0.018), skin flaking or peeling (0.63 vs. 0.06, p = 0.035), blistering (0.74 vs. 0.06, p = 0.028), pruritis (2.53 vs. 0.87, p < 0.001), erythema (4.24 vs. 2.0, p <0.001), telangiectasias (1.0 vs. 0.28, p = 0.021). Additionally, patients receiving moderate hypofractionation reported significantly worse changes from baseline at EOT in breast tenderness (-2.25 vs. -.86, p = 0.02), telangiectasia (-0.81 vs. 0.18, p = 0.012), skin discoloration (-4.31 vs. -1.04, p < 0.001), skin flaking or peeling (-.55 vs. 0.04, p = 0.053), blistering (-0.82 vs. -0.07, p = 0.033), and pruritus (-2.27 vs. -.67, p = 0.002). There was a return to baseline in all patient-reported breast domains by 3 months (p >0.05) in both arms.

CONCLUSION

Ultra-hypofractionated whole breast irradiation, consisting of 25 Gy in 5 fractions, provided comparable provider assessed toxicity and cosmetic outcomes to 40 Gy in 15 fractions. At the EOT assessment, ultra-hypofractionation had a better patient reported toxicity profile. Our findings provide further evidence to support daily ultra-hypofractionated whole breast radiotherapy as an appropriate treatment option for early-stage breast cancer.

Oncologic Outcomes of Conventionally Fractionated, Hypofractionated, and Stereotactic Body Spot-Scanned Proton Radiation Therapy for Prostate Cancer: The Mayo Clinic Experience

PURPOSE/OBJECTIVE(S)

Spot/pencil beam scanned proton therapy is a relatively new technology with fundamental differences from double scattered or IMRT. We aimed to report the long-term oncologic outcomes of a contemporary prospective series of patients treated with spot-scanned proton therapy (SSPT).

MATERIALS/METHODS

An IRB-approved prospective registry identified patients with prostate cancer treated with proton therapy between January 2016 and December 2018. Descriptive statistics were calculated for all patients. Clinical, demographic, and treatment characteristics were gathered and analyzed. Kaplan-Meier curves were generated to estimate survival and recurrence rates. Outcomes assessed included 5-year overall survival (OS), 5-year local control (LC), biochemical failure (BF), regional and distant failures, and physician-reported adverse events (AEs). Biochemical failure was defined as rise in PSA ≥ 2.0 ng/mL above nadir PSA. Acute and chronic gastrointestinal (GI) and genitourinary (GU) grade 2+ and grade 3+ baseline-adjusted AEs were assigned using CTCAE v5.0. All failures were re-staged with PET C-11 or PSMA.

RESULTS

With a median follow up of 4.4 years (IQR 3.7 - 5), two hundred and eighty-six prostate cancer patients with a median age of 72 (IQR 67.5 - 77) were treated with spot-scanned proton radiation. The median Gleason grade group was 3 (IQR 2 - 4). The median pre-RT PSA was 6.9 ng/mL (IQR 4.3 - 10.5). Median T-stage was T1c. Nearly 64% of all patients were on androgen deprivation therapy at the time of initiating radiation treatment. The median total radiation dose was 79.2 Gy delivered over 44 fractions, 70 Gy over 28 fractions, and 38 Gy over 5 fractions for CF, HF, and SBRT regimens, respectively. The BF rate for all patients was 8.4%. The 5-year LC rates for CF, HF, and SBRT were 100% (95% CI: 100 - 100), 100% (95% CI: 100 - 100), and 97.3% (95% CI: 92.2 - 100), respectively (p = 0.07). Regional recurrences occurred in 12 (4.2%) patients: 8 (5.6%) treated with CF, 2 (2.1%) with HF, and 2 (4.3%) with SBRT (p = 0.62). Distant metastatic failures occurred in 12 patients (4.2%): 5 (3.5%) treated with CF, 7 (7.4%) with HF, and none with SBRT (0%) (p = 0.052). The 5-year OS for patients treated with CF, HF, and SBRT SSPT were 88.2% (95% CI: 81.8 - 95), 86.2% (95% CI: 77.6 - 95.6), and 97.2% (95% CI: 92 - 100), respectively (p = 0.1). Acute and chronic grade 2+ GI baseline-adjusted AEs occurred in 8 (2.8%) and 51 (17.8%) patients, respectively. Acute and chronic grade 3+ GI baseline-adjusted AEs occurred in 3 (1%) and 4 (1.4%) patients, respectively. Acute and chronic grade 2+ GU-related AEs were observed in 72 (25.2%) and 63 (22%) patients, respectively. Acute and chronic grade 3+ GU toxicity was observed in 3 (1%) and 6 (2.1%) patients, respectively.

CONCLUSION

Spot-scanned proton radiation therapy provides high local control rates and excellent oncologic outcomes across different fractionation schedules with low long-term AE rates.

Hypoxia-activated prodrugs of phenolic olaparib analogues for tumour-selective chemosensitisation

Poly(ADP-ribose)polymerase inhibitors (PARPi) are used for treatment of tumours with a defect in homologous recombination (HR) repair. Combination with radio- or chemotherapy could broaden their applicability but a major hurdle is enhancement of normal tissue toxicity. Development of hypoxia-activated prodrugs (HAPs) of PARPi has potential to restrict PARP inhibition to tumours thereby avoiding off-target toxicity. We have designed and synthesised phenolic derivatives of olaparib (termed phenolaparibs) and corresponding ether-linked HAPs. Phenolaparib cytotoxicity in HR-proficient and deficient cell lines was consistent with inhibition of PARP-1. Prodrugs were deactivated relative to phenolaparibs in biochemical PARP-1 inhibition assays, and cell culture. Prodrug 7 was selectively converted to phenolaparib 4 under hypoxia and demonstrated hypoxia-selective cytotoxicity, including chemosensitisation of HR-proficient cells in combination with temozolomide. This work demonstrates the feasibility of a HAP approach to PARPi for use in combination therapies.

Design, Synthesis and Anticancer Evaluation of Nitroimidazole Radiosensitisers

The role of hypoxic tumour cells in resistance to radiotherapy, and in suppression of immune response, continues to endorse tumour hypoxia as a bona fide, yet largely untapped, drug target. Radiotherapy innovations such as stereotactic body radiotherapy herald new opportunities for classical oxygen-mimetic radiosensitisers. Only nimorazole is used clinically as a radiosensitiser, and there is a dearth of new radiosensitisers in development. In this report, we augment previous work to present new nitroimidazole alkylsulfonamides and we document their cytotoxicity and ability to radiosensitise anoxic tumour cells in vitro. We compare radiosensitisation with etanidazole and earlier nitroimidazole sulfonamide analogues and we identify 2-nitroimidazole and 5-nitroimidazole analogues with marked tumour radiosensitisation in ex vivo assays of surviving clonogens and with in vivo tumour growth inhibition.

Patient-reported outcomes version of the common terminology criteria for adverse events and quality-of-life linear analogue self-assessment in breast cancer patients receiving radiation therapy: single-institution prospective registry

Purpose/objectives

We sought to investigate the impact of patient-reported outcomes version of the common terminology criteria for adverse events (PRO-CTCAE) on overall quality-of-life (QOL) employing linear analogue self-assessment (LASA) in breast cancer (BC) patients undergoing radiation therapy (RT).

Materials/methods

All patients treated with RT for BC with curative intent from 2015 to 2019 at our institution were included. Breast specific PRO-CTCAE and overall QOL LASA questionnaires were administered at baseline, end-of-treatment, 3, 6, 12 months, and then annually. Minimal clinically important difference in overall QOL was a 10-point change in LASA. Hypofractionation was any treatment > 2 Gy per fraction. Mixed models for repeated measures were used to determine the association of PRO-CTCAE and overall QOL LASA.

Results

Three hundred thirty-one (331) patients with a median follow-up of 3.1 years (range 0.4–4.9) were included. Average overall QOL LASA scores were 78.5 at baseline, 79.8 at end-of-treatment, 79.8 at 3 months, 77.1 at 6 months, 79.4 at 12 months, and 79.7 at 24 months. On univariate analysis, patients reporting a grade ≥ 3 PRO-CTCAE had, on average, a 10.4-point reduction in overall LASA QOL (p < 0.0001). On multivariate analysis, not being treated with hypofractionation and higher BMI were predictive for worse overall LASA QOL with a 10-point reduction in LASA for patients reporting a grade ≥ 3 PRO-CTCAE (p < 0.0001).

Conclusions

Patients reporting a grade ≥ 3 PRO-CTCAE experienced statistically significant and clinically meaningful deterioration in overall QOL LASA. Hypofractionation improved QOL while higher BMI predicted for worse QOL. PRO-CTCAE should be integrated into future clinical trials.

Abstract PO-018: Hypoxia activated prodrugs of DNA-dependent protein kinase inhibitors as radiosensitisers of head and neck squamous cell carcinomas

Inhibition of the repair of radiation-induced DNA double strand breaks offers the potential to sensitize tumors to radiation therapy. DNA-dependent protein kinase (DNA-PK) is a well validated target for radiosensitisation, but inhibition also has the potential to radiosensitize normal tissues within the radiation field, and to target normal tissue functions outside of DNA-PK’s canonical role in DNA repair. Exploiting hypoxia to selectively activate hypoxia-activated prodrugs of DNA-PK inhibitors (DNA-PKi) in tumors may enhance tumor selectivity, with the advantage of sensitizing the most radioresistant (hypoxic) subpopulation, as well as sensitizing adjacent oxic cells through a local bystander effect. We recently conducted a drug discovery campaign, scaffold-hopping from the pan-PIKK inhibitor dactolisib to identify new DNA-PKi. We screened compounds against three signal targets DNA-PK, PI3Kα and mTOR, and determined in vitro sensitization of UT-SCC-54C head and neck squamous cell carcinoma (HNSCC) cells using a growth inhibition endpoint. We identified a highly selective lead DNA-PKi, SN39536, and a corresponding hypoxia-activated prodrug, SN39884. SN39536 is an effective inhibitor of DNA-PK activity, both biochemically and in cells, with substantial selectivity compared to phosphoinositide-3-kinase (PI3K) enzymes and other PI3K-related kinase enzymes. SN39536 provided radiosensitization of DNA-PK proficient HAP1 cells, but was inactive against isogenic cells with knockout of the DNA-PK catalytic subunit (PRKDC), demonstrating on-mechanism activity. SN39536 also provided robust radiosensitization of oxic UT-SCC-54C HNSCC cells using a clonogenic endpoint. Prodrug SN39884 was deactivated as a DNA-PKi and released SN39536 under reductive conditions. Incubation of the prodrug with HCT116 cells overexpressing cytochrome P450 oxidoreductase or UT-SCC-54C cells led to hypoxia-dependent metabolism of the prodrug and efficient release of SN39536. SN39536 effectively sensitized UT-SCC-54C cells to radiation under either aerobic or anoxic conditions, while prodrug SN39884 only sensitized cells under anoxia. SN39536 and its prodrug also demonstrated radiosensitization of hypoxic cells in UT-SCC-54C tumor xenografts using an ex vivo clonogenic survival endpoint. We have identified a new class of potent and selective DNA-PK inhibitors and demonstrated the ability of a hypoxia-activated prodrug to selectively release the inhibitor under hypoxia in vitro and in vivo.

Citation Format: Michael P. Hay, Way W. Wong, Benjamin D. Dickson, Gary J. Cheng, Liew P. Liew, Cho R. Hong, William R. Wilson, Stephen M. Jamieson. Hypoxia activated prodrugs of DNA-dependent protein kinase inhibitors as radiosensitisers of head and neck squamous cell carcinomas [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-018.

Cardiovascular disease-related mortality and factors associated with cardiovascular events in the TREAT Asia HIV Observational Database (TAHOD)

OBJECTIVES

With aging of the HIV-positive population, cardiovascular disease (CVD) increasingly contributes to morbidity and mortality. We investigated CVD-related and other causes of death (CODs) and factors associated with CVD in a multi-country Asian HIV-positive cohort.

METHODS

Patient data from 2003-2017 were obtained from the Therapeutics, Research, Education and AIDS Training in Asia (TREAT Asia) HIV Observational Database (TAHOD). We included patients on antiretroviral therapy (ART) with > 1 day of follow-up. Cumulative incidences were plotted for CVD-related, AIDS-related, non-AIDS-related, and unknown CODs, and any CVD (i.e. fatal and nonfatal). Competing risk regression was used to assess risk factors of any CVD.

RESULTS

Of 8069 patients with a median follow-up of 7.3 years [interquartile range (IQR) 4.4-10.7 years], 378 patients died [incidence rate (IR) 6.2 per 1000 person-years (PY)], and this total included 22 CVD-related deaths (IR 0.36 per 1000 PY). Factors significantly associated with any CVD event (IR 2.2 per 1000 PY) were older age [sub-hazard ratio (sHR) 2.21; 95% confidence interval (CI) 1.36-3.58 for age 41-50 years; sHR 5.52; 95% CI 3.43-8.91 for ≥ 51 years, compared with < 40 years], high blood pressure (sHR 1.62; 95% CI 1.04-2.52), high total cholesterol (sHR 1.89; 95% CI 1.27-2.82), high triglycerides (sHR 1.55; 95% CI 1.02-2.37) and high body mass index (BMI) (sHR 1.66; 95% CI 1.12-2.46). CVD crude IRs were lower in the later ART initiation period and in lower middle- and upper middle-income countries.

CONCLUSIONS

The development of fatal and nonfatal CVD events in our cohort was associated with older age, and treatable risk factors such as high blood pressure, triglycerides, total cholesterol and BMI. Lower CVD event rates in middle-income countries may indicate under-diagnosis of CVD in Asian-Pacific resource-limited settings.

Evofosfamide for the treatment of human papillomavirus-negative head and neck squamous cell carcinoma

Evofosfamide (TH-302) is a clinical-stage hypoxia-activated prodrug of a DNA-crosslinking nitrogen mustard that has potential utility for human papillomavirus (HPV) negative head and neck squamous cell carcinoma (HNSCC), in which tumor hypoxia limits treatment outcome. We report the preclinical efficacy, target engagement, preliminary predictive biomarkers and initial clinical activity of evofosfamide for HPV-negative HNSCC. Evofosfamide was assessed in 22 genomically characterized cell lines and 7 cell line-derived xenograft (CDX), patient-derived xenograft (PDX), orthotopic, and syngeneic tumor models. Biomarker analysis used RNA sequencing, whole-exome sequencing, and whole-genome CRISPR knockout screens. Five advanced/metastatic HNSCC patients received evofosfamide monotherapy (480 mg/m2 qw × 3 each month) in a phase 2 study. Evofosfamide was potent and highly selective for hypoxic HNSCC cells. Proliferative rate was a predominant evofosfamide sensitivity determinant and a proliferation metagene correlated with activity in CDX models. Evofosfamide showed efficacy as monotherapy and with radiotherapy in PDX models, augmented CTLA-4 blockade in syngeneic tumors, and reduced hypoxia in nodes disseminated from an orthotopic model. Of 5 advanced HNSCC patients treated with evofosfamide, 2 showed partial responses while 3 had stable disease. In conclusion, evofosfamide shows promising efficacy in aggressive HPV-negative HNSCC, with predictive biomarkers in development to support further clinical evaluation in this indication.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Smoking and projected cardiovascular risk in an HIV-positive Asian regional cohort

OBJECTIVES

The aim of the study was to assess the prevalence and characteristics associated with current smoking in an Asian HIV-positive cohort, to calculate the predictive risks of cardiovascular disease (CVD), coronary heart disease (CHD) and myocardial infarction (MI), and to identify the impact that simulated interventions may have.

METHODS

Logistic regression analysis was used to distinguish associated current smoking characteristics. Five-year predictive risks of CVD, CHD and MI and the impact of simulated interventions were calculated utilizing the Data Collection on Adverse Effects of Anti-HIV Drugs Study (D:A:D) algorithm.

RESULTS

Smoking status data were collected from 4274 participants and 1496 of these had sufficient data for simulated intervention calculations. Current smoking prevalence in these two groups was similar (23.2% vs. 19.9%, respectively). Characteristics associated with current smoking included age > 50 years compared with 30-39 years [odds ratio (OR) 0.65; 95% confidence interval (CI) 0.51-0.83], HIV exposure through injecting drug use compared with heterosexual exposure (OR 3.03; 95% CI 2.25-4.07), and receiving antiretroviral therapy (ART) at study sites in Singapore, South Korea, Malaysia, Japan and Vietnam in comparison to Thailand (all OR > 2). Women were less likely to smoke than men (OR 0.11; 95% CI 0.08-0.14). In simulated interventions, smoking cessation demonstrated the greatest impact in reducing CVD and CHD risk and closely approximated the impact of switching from abacavir to an alternate antiretroviral in the reduction of 5-year MI risk.

CONCLUSIONS

Multiple interventions could reduce CVD, CHD and MI risk in Asian HIV-positive patients, with smoking cessation potentially being the most influential.

Abstract 169: Preclinical efficacy and sensitivity determinants of evofosfamide in molecularly defined models of head and neck squamous cell carcinoma

Tumor hypoxia is prevalent in head and neck squamous cell carcinoma (HNSCC), where it limits radiotherapy outcomes. Hypoxia-activated prodrugs (HAPs) have been developed to target hypoxic regions of tumors. These agents undergo oxygen-sensitive reductive activation, thereby delivering cytotoxic species within hypoxic cells. This study investigated the efficacy and sensitivity determinants of the clinical-stage HAP evofosfamide (TH-302) using molecularly-characterized models of HNSCC. We deployed a collection of 27 HPV-negative HNSCC cell lines derived from lesions of varying TNM stages and primary, nodal or recurrent sites. The collection was characterized for gene expression by RNA-seq, from which somatic variants were also called. Their transcriptomic features were investigated in the context of pan-cancer TCGA data by hierarchical clustering. The potency and hypoxic selectivity of 3 HAPs - evofosfamide, PR-104A and SN30000 - were assessed by antiproliferative assay in 22 lines and compared to bromo-isophosphoramide mustard (Br-IPM), cisplatin and 5-FU. The antitumor activity of evofosfamide (50 mg/kg qdx5 for 2-3 cycles with or without a single 10 Gy dose of radiation on day 5 of cycle 1) was evaluated in HNSCC xenografts in addition to a PDX isolated from an SCC of the glottic larynx. The hypoxic fraction at baseline and after 5 days of treatment was quantified by pimonidazole staining. Genetic modifiers of sensitivity to evofosfamide and its cytotoxic metabolite Br-IPM were explored through whole-genome CRISPR-Cas9 screens using the GeCKO v2 library. High-throughput screens with a custom shRNA pool were performed in one HNSCC and two pancreatic ductal adenocarcinoma cell lines to identify reductases responsible for the activation of evofosfamide in hypoxic cells. Evofosfamide was more potent and more selective for hypoxic HNSCC cells in vitro than PR-104A or SN30000. Cell line sensitivity to evofosfamide was correlated with Br-IPM and cisplatin but not with PR-104A, SN30000 or 5-FU, indicating distinct sensitivity determinants. Evidence of antitumor activity with evofosfamide was observed in vivo. CRISPR screens identified potential evofosfamide sensitivity genes that were reproducibly enriched following drug exposure. Reductase-focused RNA interference screens defined a cluster of sensitivity genes that mapped to mitochondrial electron transport, whereas shRNA’s targeted against presumed activating enzymes such as POR were not enriched. Concentration-dependent oxidation of cytochrome a and decreased respiration was observed in cells exposed to evofosfamide, suggesting reduction by mitochondrial complexes. This study provides a rationale for the clinical evaluation of evofosfamide with radiotherapy in genetically defined subsets of HNSCC patients.

Citation Format: Francis W. Hunter, Avik Shome, Dan Li, Way W. Wong, Peter Tsai, Nooriyah Poonawala, Purvi M. Kakadiya, Troy M. Ketelä, Maria K. Kondratyev, Courtney R. Lynch, Tet-Woo Lee, Khanh B. Tran, Jules B. Devaux, Rachel Zussman, Cho R. Hong, Dennis Kee, Andrew M. Macann, Anthony J. Hickey, Stefan K. Bohlander, Cristin G. Print, William R. Wilson, Bradly G. Wouters, Stephen M. Jamieson. Preclinical efficacy and sensitivity determinants of evofosfamide in molecularly defined models of head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 169. doi:10.1158/1538-7445.AM2017-169

Phase sensitive SPR sensor for wide dynamic range detection

Phase detection has been utilized to enhance the sensitivity of surface plasmon resonance (SPR) sensors for a long time. However, an inherent drawback for phase sensitive SPR sensors are their limited dynamic range, which has greatly hindered wide applications of such sensors. In this Letter, a design combining phase detection and angular interrogation has been proposed to provide an SPR sensor with both high sensitivity and wide dynamic range. As a result, a resolution of 2.2×10^-7 RIU with a dynamic range of over 0.06 RIU has been achieved simultaneously. An added advantage of this design is the flexibility for sensitivity and dynamic range adjustment.

The first case of Silver-Russell syndrome accompanied by linea alba hernia in China

A 10-month-old Chinese boy presented with delayed motor development for seven months. Blood and biochemistry investigations revealed no abnormalities. The physical examination showed poor postnatal growth (below -2 standard deviation from the mean at diagnosis), preservation of the occipitofrontal head circumference with delayed closure of the anterior fontanel, a classical triangular facial phenotype, asymmetry of the lower extremities and other characteristic features that fulfil the diagnostic criteria of Silver-Russell syndrome clinically. As PubMed and web searches revealed no similar findings, we believe that this may be the first case of Silver-Russell syndrome with linea alba hernia and pes varus reported in China, and possibly the world. The genetic deficit responsible for this case is still under investigation.

The design of intracellular oscillators that interact with metabolism

Biological oscillations such as circadian rhythms are ubiquitous in nature and have attracted significant attention because of their intriguing dynamics and important biological roles. Understanding of such sophisticated and robust oscillators requires more than the traditional reductionist approach. Recently, a synthetic approach similar to the design of engineering machinery has provided a valuable alternative for testing hypothetical operating principles. These man-made genetic circuits and gene-metabolic circuits are designed based on physical concepts, guided by mathematical models, and constrained by biological and chemical reality. While still primitive compared with the natural circuits, the designed gene-metabolic oscillator has begun to show hallmarks of circadian rhythms such as temperature compensation and close interaction with metabolism.

Transcriptional regulation and metabolism

Understanding organisms from a systems perspective is essential for predicting cellular behaviour as well as designing gene-metabolic circuits for novel functions. The structure, dynamics and interactions of cellular networks are all vital components of systems biology. To facilitate investigation of these aspects, we have developed an integrative technique called network component analysis, which utilizes mRNA expression and transcriptional network connectivity to determine network component dynamics, functions and interactions. This approach has been applied to elucidate transcription factor dynamics in Saccharomyces cerevisiae cell-cycle regulation, detect cross-talks in Escherichia coli two-component signalling pathways, and characterize E. coli carbon source transition. An ultimate test of system-wide understanding is the ability to design and construct novel gene-metabolic circuits. To this end, artificial feedback regulation, cell-cell communication and oscillatory circuits have been constructed, which demonstrate the design principles of gene-metabolic regulation in the cell.

Development and validation of the interview version of the Hong Kong Chinese WHOQOL-BREF

INTRODUCTION

The Hong Kong Chinese version of the WHOQOL-BREF was designed as a self-administered questionnaire and has limitations in clinical application on subjects who have limitations in reading or writing. An interview version is therefore needed to avoid sampling biases in clinical studies. Since there are significant differences in the written Chinese and spoken Cantonese, which is a dialect commonly spoken among people in Hong Kong, and adaptation process for converting the written Chinese into spoken Cantonese was necessary. The interview version was designed to allow administration in both face-to-face interview and telephone interview mode.

METHODS

Three members of the research team translated the formal written Chinese in the self-administered version of the WHOQOL-BREF(HK) into colloquial Cantonese separately. Brief notes extracted from the facet definitions of the WHOQOL-100 were added in brackets after some questions to further explain the intention of the questions. Two series of focus groups were conducted and subsequently the field test version was produced. 329 subjects were recruited by convenient sampling method for the field test.

RESULTS

The interview version and the self-administered version was found equivalent. The ICC values of the domain scores ranged from 0.73 in the environment domain to 0.83 in the psychological domain. The face-to-face interview and telephone interview mode of administration were also found equivalent. The ICC for the domain scores ranged from 0.76 in the social interaction domain to 0.84 in the psychological domain. The other psychometric properties of the interview version were found comparable to the self-administered version.

CONCLUSION

The self-administered and the interview version of the WHOQOL-BREF are regarded as identical in group comparison. The authors advise that it is acceptable to use different versions on different subjects in the same study, provided that the same version is applied on the same subject throughout the study.

Bone mineral mass in overweight and obese children: diminished or enhanced?

Childhood obesity has become a worldwide health problem. Recent studies have suggested that obese and overweight children have lower bone mass. We used dual-energy X-ray absorptiometry to examine the relation between bone mineral content (BMC) and body fatness (%Fat) in healthy children. Obese children (%Fat>30%) had higher BMC compared with age-, gender-, and ethnic-matched children with normal adiposity (%Fat<25%). When adjusted for height, these differences were less significant. We conclude obese children do not have lower whole-body BMC when compared with leaner children, even when adjusted for height, age, gender, and ethnicity.

Brachiocephalic-superior vena cava metallic stenting in malignant superior vena cava obstruction

INTRODUCTION

We studied the effectiveness of unilateral brachiocephalic (BC)-superior vena cava (SVC) metallic stent therapy in malignant SVC obstruction.

MATERIALS AND METHODS

From November 1998 to February 2002, SVC stenting was performed in 11 patients with symptomatic malignant SVC obstruction. There were 10 males and 1 female, with a mean age of 64.2 years (range, 37 to 78 years). The computed tomography (CT) scan and superior vena cavogram findings of all patients showed malignant SVC obstruction. Both internal jugular veins were patent in all patients by ultrasound. SVC stenting was performed with Wallstent (Boston Scientific, Minneapolis, MN, USA) in 10 patients and Memotherm stent (Bard angiomed, Wachhausstrasse, Germany) in 1 patient. Pressure gradient, duration of the procedure, peri-procedural morbidity and mortality and the general well-being of the patients were reviewed.

RESULTS

SVC stenting was performed at a mean duration of 9.6 days (range, 3 to 30 days) after presentation. All were technically successful with 10 across the right BC-SVC and 1 across the left BC-SVC. There was no peri-procedural morbidity or mortality. The entire procedure was completed at a mean duration of 115 minutes (range, 75 to 225 minutes) with good angiographic and pressure results. Immediate symptomatic relief of SVC syndrome was achieved in 10 patients who had received prompt work-up and stenting 3 to 18 days after presentation. The remaining patient, who received work-up and stenting 30 days after presentation, remained dyspnoeic and died of pneumonia 7 days after the procedure.

CONCLUSION

Unilateral BC-SVC metallic stenting is an effective measure in malignant SVC obstruction. Prompt pre-stenting work-up and stenting are recommended to achieve a longer symptomatic relief period.

Triple ionization of lithium by electron impact

Ejection of the three electrons from lithium in a single electron collision has been observed for the first time. Triply charged lithium was observed in an ion time-of-flight spectrum following electron impact on a sample of ultracold, trapped lithium. The higher signal/background afforded by the trap environment made the observation of Li3+ possible. We measured the ratios of triple-to-double and double-to-single ionization at an impact energy of 1000 eV. The 3+/2+ ratio is approximately 0.001, a value 2 orders of magnitude lower than semiempirical predictions. We present a simple method that uses photoionization data combined with sum-rule analysis to predict the asymptotic charge-state ratios. The sum-rule predictions compare reasonably with experiment and shake calculations, but disagree sharply with the semiempirical estimates.

Functional studies of yeast actin mutants corresponding to human cardiomyopathy mutations

The molecular mechanisms by which different mutations in actin lead to distinct cardiomyopathies are unknown. Here, actin mutants corresponding to alpha-cardiac actin mutations causing hypertrophic cardiomyopathy [(HCM) P164A and A331P] and dilated cardiomyopathy [(DCM) R312H and E361G] were expressed in yeast and purified for in vitro functional studies. While P164A appeared unaltered compared to wild-type (WT) actin, A331P function was impaired. A331P showed reduced stability in circular dichroism melting experiments; its monomer unfolding transition was 10 degrees C lower compared to WT actin. Additionally, in vitro filament formation was hampered, and yeast cell cultures were temperature sensitive, implying perturbations in actin-actin interactions. Filament instability of the A331P mutant actin could lead to actomyosin dysfunction observed in HCM. Yeast strains harboring the R312H mutation did not grow well in culture, suggesting that cell viability is compromised. The E361G substitution is located at an alpha-actinin binding region where the actin filament is anchored. The mutant actin, though unaltered in the in vitro motility and standard actomyosin functions, had a threefold reduction in alpha-actinin binding. This could result in impairment of force-transduction in muscle fibers, and a DCM phenotype.

Clinical characteristics of Group G streptococcal bacteremia in Taiwan

The results of this retrospective study showed that Group G streptococcal bacteremia was an acute febrile disease with low mortality. Most patients were > 60 y old but there was a strong association between age < 60 y and malignancy. Cases clustered in summer and the most common port of entry was the skin.

Structure-based design of caspase-1 inhibitor containing a diphenyl ether sulfonamide

A series of compounds was designed and prepared as inhibitors of interleukin-1beta converting enzyme (ICE), also known as caspase-1. These inhibitors, which employ a diphenyl ether sulfonamide, were designed to improve potency by forming favorable interactions between the diphenyl ether rings and the prime side hydrophobic region. An X-ray crystal structure of a representative member of the diphenyl ether sulfonamide series bound to the active site of caspase-1 was obtained.

Up-regulation of Fas ligand expression by human cytomegalovirus immediate-early gene product 2: a novel mechanism in cytomegalovirus-induced apoptosis in human retina

Human CMV (HCMV) is an important pathogen that causes widespread diseases in immunocompromised individuals. Among the opportunistic HCMV infections, HCMV retinitis is most common in transplant recipients and AIDS patients. It often leads to blindness if left untreated. The question as to how HCMV infection causes retinal pathogenesis remains unresolved. Here, we report that viral immediate-early gene product 2 (IE2), but not IE1, up-regulates the Fas ligand (FasL) expression in HCMV-infected human retinal pigment epithelium cells. Increased secretion of FasL from virally infected cells into cultured medium was observed upon HCMV infection. The capability of such cell-free medium to induce apoptosis of Fas (CD95)-expressing Jurkat cells further implies that Fas-FasL interaction might mediate cell death in the lesion of HCMV retinitis. To support this idea, we observed augmented soluble FasL levels in vitreous from AIDS patients with HCMV retinitis as compared with that from AIDS patients without HCMV infection. In addition, by in situ hybridization and immunohistochemistry, we detected enhanced signals of FasL, the existence of viral IE Ags and apoptotic cells at the same sites in the lesion of HCMV-infected retina. These results strongly suggest that IE2 induction of FasL expression in human retina might be an important event that takes place in the early stage of infection and finally leads to visual loss in individuals affiliated with HCMV retinitis.

Body composition in prepubertal girls: comparison of six methods

OBJECTIVE

To compare estimates of fat mass (FM), fat-free mass (FFM) and percentage body fat (%fat) by six different methods in prepubertal girls.

DESIGN

Cross-sectional study.

SUBJECTS

Normal-weight, multi-ethnic, prepubertal girls (age=8.5+/-0.4 y, n=101).

MEASUREMENTS

Body composition was measured in each child by anthropometry (skinfold thickness using Slaughter equation), dual-energy X-ray absorptiometry (DXA), total body potassium (TBK), isotope dilution for total body water measurement (TBW), multifrequency bioelectrical impedance spectroscopy (BIS), and total body electrical conductivity (TOBEC).

RESULTS

TOBEC and skinfold thickness yielded the lowest values of FM followed by DXA, TBK, TBW and BIS, with BIS giving the highest value of FM. All methods were significantly different for FFM, FM and %fat (P<0.001), except FFM by DXA and TBK. The Bland-Altman limits of agreement among the methods reveal that they are not directly interchangeable for FM, FFM, or %fat. The largest mean difference for FM was between TOBEC and BIS (-2.90 kg), whereas the smallest mean difference was between TOBEC and skinfold thickness (-0.14 kg). For FFM, the largest mean difference was also between TOBEC and BIS (2.83 kg), but the smallest mean difference for FFM was between DXA and TBK (-0.03 kg). For %fat, the mean differences were larger, -10.5% for TOBEC and BIS and+9.7% for skinfold thickness and BIS. The closest two techniques for %fat were TOBEC and skinfold thickness (mean difference of -0.62%) and DXA and TBK (-1.81%).

CONCLUSIONS

We found that estimates of body composition in prepubertal 8-y-old girls are highly method-dependent and that the six methods studied (DXA, TBK, TBW, TOBEC, BIS and anthropometry) are not directly interchangeable.

Characteristics of patients with Burkholderia cepacia bacteremia

Burkholderia cepacia has become an important pathogen of infections in immunocompromised and nosocomial patients. The characteristics of 42 episodes of B. cepacia bacteremia in 40 patients admitted to the Taipei Veterans General Hospital between January 1997 and December 1999 were retrospectively analyzed. Factors that adversely influenced the mortality rate included respiratory failure, an unknown infection source, a period in an intensive care unit, and shock. Most of the patients had serious underlying diseases, such as diabetes mellitus, malignancy, congestive heart failure, and chronic obstructive pulmonary disease. The mean time for a positive blood culture was 45 days after admission. The overall mortality rate was 28.6% (12/42), and 44.4% (12/27) of all deaths were directly related to B. cepacia bacteremia. Polymicrobial bacteremia was found in 5 patients. Ceftazidime was the most effective antimicrobial agent in vitro, whereas chloramphenicol, imipenem, and trimethoprim/sulfamethoxazole were less effective alternatives. Appropriate antibiotic therapy was given to 30 patients, most of whom responded to the therapy except for 5 who died despite receiving appropriate treatment. Although B. cepacia infection develops in a relatively small proportion of hospitalized individuals, it has a major impact on morbidity and mortality. In view of the fact that B. cepacia develops resistance to a wide range of antimicrobial agents, ceftazidime and/or trimethoprim/sulfamethoxazole should be the drug of choice for empiric therapy.

Blocking protein geranylgeranylation is essential for lovastatin-induced apoptosis of human acute myeloid leukemia cells

Lovastatin is an inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the major regulatory enzyme of the mevalonate pathway. We have previously reported that lovastatin induces a significant apoptotic response in human acute myeloid leukemia (AML) cells. To identify the critical biochemical mechanism(s) essential for lovastatin-induced apoptosis, add-back experiments were conducted to determine which downstream product(s) of the mevalonate pathway could suppress this apoptotic response. Apoptosis induced by lovastatin was abrogated by mevalonate (MVA) and geranylgeranyl pyrophosphate (GGPP), and was partially inhibited by farnesyl pyrophosphate (FPP). Other products of the mevalonate pathway including cholesterol, squalene, lanosterol, desmosterol, dolichol, dolichol phosphate, ubiquinone, and isopentenyladenine did not affect lovastatin-induced apoptosis in AML cells. Our results suggest that inhibiting geranylgeranylation of target proteins is the predominant mechanism of lovastatin-induced apoptosis in AML cells. In support of this hypothesis, the geranylgeranyl transferase inhibitor (GGTI-298) mimicked the effect of lovastatin, whereas the farnesyl transferase inhibitor (FTI-277) was much less effective at triggering apoptosis in AML cells. Inhibition of geranylgeranylation was monitored and associated with the apoptotic response induced by lovastatin and GGTI-298 in the AML cells. We conclude that blockage of the mevalonate pathway, particularly inhibition of protein geranylgeranylation holds a critical role in the mechanism of lovastatin-induced apoptosis in AML cells.

Z score prediction model for assessment of bone mineral content in pediatric diseases

The objective of this study was to develop an anthropometry-based prediction model for the assessment of bone mineral content (BMC) in children. Dual-energy X-ray absorptiometry (DXA) was used to measure whole-body BMC in a heterogeneous cohort of 982 healthy children, aged 5-18 years, from three ethnic groups (407 European- American [EA], 285 black, and 290 Mexican-American [MA]). The best model was based on log transformations of BMC and height, adjusted for age, gender, and ethnicity. The mean +/- SD for the measured/predicted in ratio was 1.000 +/- 0.017 for the calibration population. The model was verified in a second independent group of 588 healthy children (measured/predicted In ratio = 1.000 +/- 0.018). For clinical use, the ratio values were converted to a standardized Z score scale. The whole-body BMC status of 106 children with various diseases (42 cystic fibrosis [CF], 29 juvenile dermatomyositis [JDM], 15 liver disease [LD], 6 Rett syndrome [RS], and 14 human immunodeficiency virus [HIV]) was evaluated. Thirty-nine patients had Z scores less than -1.5, which suggest low bone mineral mass. Furthermore, 22 of these patients had severe abnormalities as indicated by Z scores less than -2.5. These preliminary findings indicate that the prediction model should prove useful in determining potential bone mineral deficits in individual pediatric patients.

Cerivastatin triggers tumor-specific apoptosis with higher efficacy than lovastatin

The statin family of drugs inhibits 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, the rate-limiting enzyme of the mevalonate pathway, and is used clinically as a safe and effective approach in the control of hypercholesterolemia. We have shown previously (Dimitroulakos, J., Nohynek, D., Backway, K. L., Hedley, D. W., Yeger, H., Freedman, M. H., Minden, M D., and Penn, L. Z. Increased sensitivity of acute myelogenous leukemias to lovastatin-induced apoptosis: a potential therapeutic approach. Blood, 93: 1308-1318, 1999) that lovastatin, a prototypic member of the statin family, can induce apoptosis of human acute myeloid leukemia (AML) cells in a sensitive and specific manner. In the present study, we evaluated the relative potency and mechanism of action of the newer synthetic statins, fluvastatin, atorvastatin, and cerivastatin, to trigger tumor-specific apoptosis. Cerivastatin is at least 10 times more potent than the other statins at inducing apoptosis in AML cell lines. Cerivastatin-induced apoptosis is reversible with the addition of the immediate product of the HMG-CoA reductase reaction, mevalonate, or with a distal product of the pathway, geranylgeranyl pyrophosphate. This suggests protein geranylgeranylation is an essential downstream component of the mevalonate pathway for cerivastatin similar to lovastatin-induced apoptosis. The enhanced potency of cerivastatin expands the number of AML patient samples as well as the types of malignancies, which respond to statin-induced apoptosis with acute sensitivity. Cells derived from acute lymphocytic leukemia are only weakly sensitive to lovastatin cytotoxicity but show robust response to cerivastatin. Importantly, cerivastatin is not cytotoxic to nontransformed human bone marrow progenitors. These results strongly support the further testing of cerivastatin as a novel anticancer therapeutic alone and in combination with other agents in vivo.

High-performance multiplex SNP analysis of three hemochromatosis-related mutations with capillary array electrophoresis microplates

An assay is described for high-throughput single nucleotide polymorphism (SNP) genotyping on a microfabricated capillary array electrophoresis (CAE) microchip. The assay targets the three common variants at the HFE locus associated with the genetic disease hereditary hemochromatosis (HHC). The assay employs allele-specific PCR (ASPCR) for the C282Y (845g->a), H63D (187c->g), and S65C (193a->t) variants using fluorescently-labeled energy-transfer (ET) allele-specific primers. Using a 96-channel radial CAE microplate, the labeled ASPCR products generated from 96 samples in a reference Caucasian population are simultaneously separated with single-base-pair resolution and genotyped in under 10 min. Detection is accomplished with a laser-excited rotary four-color fluorescence scanner. The allele-specific amplicons are differentiated on the basis of both their size and the color of the label emission. This study is the first demonstration of the combined use of ASPCR with ET primers and microfabricated radial CAE microplates to perform multiplex SNP analyses in a clinically relevant population.

Development of a treatment planning protocol for prostate treatments using intensity modulated radiotherapy

We have developed a treatment planning protocol for intensity-modulated radiation therapy of the prostate using commercially available inverse planning software. Treatment plans were developed for ten patients using the Corvus version 3.8 planning system, testing various prescription options, including tissue types, dose volume histogram values for the target and normal structures, beam arrangements, and number of intensity levels. All plans were scaled so that 95% of the clinical target volume received 75.6 Gy; mean doses to the prostate were typically 79 Gy. The reproducibility of the inverse planning algorithm was tested by repeating a set of the plans five times. Plans were deemed acceptable if they satisfied predefined dose constraints for the targets and critical organs. Figures of merit for target coverage, target dose uniformity, and organ sparing were used to rank acceptable plans. Certain systematic behaviors of the optimizer were noted: the high dose regions for both targets and critical organs were 5-10 Gy more than prescribed; reducing bladder and rectum tolerance increased the range of doses within the target; increasing the number of fields incrementally improved plan quality. A set of planning parameters was found that usually satisfied the minimum requirements. Repeating the optimization with different beam order produced similar but slightly different dose distributions, which was sometimes useful for finding acceptable solutions for difficult cases. The standard set of parameters serves as a useful starting point for individualized planning.

Cantonese consonantal development: towards a nonlinear account

Descriptions of the development of prosodic and segmental tiers of children's phonological systems have been derived from investigations of the development of English. This paper provides a preliminary description of phonological tier development in Cantonese-speaking children. Eight children, (two each at 1;7, 2;6, 3;5, and 4;2 years) named 95 pictures. The data were analysed for word, syllable, onset-rime, skeletal, and segmental tiers. The results suggested a developmental order in the acquisition of hierarchical features. Decreasing order of accuracy of the tiers was word = syllable > onset-rime = skeletal > segmental. A model of feature geometry was adopted to describe the acquisition of features. An interesting finding is the way the laryngeal feature (aspiration) was combined with place contrasts one at a time rather than all at once.

Conversion of capillary electrophoresis microchip genotyping data for analysis with Genetic Profiler software

The collection and conversion of 4-color fluorescent genotyping data from capillary array electrophoresis microchip devices and its conversion to a format easily and rapidly analyzed by Genetic Profiler genotyping software is presented. Microchip fluorescence intensity data are acquired and stored as 4-color tab-delimited text. These files are converted to electrophoretic signal data (ESD) files using a utility program (TEXT-to-ESD) written in C. TEXT-to-ESD generates an ESD file by converting text data to binary data and then appending a 632-byte ESD-file trailer. Up to 96 ESD files are then assembled into a run folder and imported into Genetic Profiler, where data are reduced to 4-color electropherograms and analyzed. In this manner, DNA fragment sizing data acquired with our high-speed electrophoretic microchip devices can be rapidly analyzed using robust commercial software. Additionally, the conversion program allows sizing of data with Genetic Profiler that have been preprocessed using other third-party software, such as BaseFinder.

Energy requirements of lactating women derived from doubly labeled water and milk energy output

Instead of using an incremental approach to assess the energy requirements of lactation, a more comprehensive approach may be taken by measuring total energy expenditure (TEE), milk energy output and energy mobilization from tissue stores. The latter approach avoids assumptions regarding energetic efficiency and changes in physical activity and adiposity. The purpose of this study was threefold: to assess the energy requirements of lactation; to compare these estimates with energy requirements in the nonpregnant, nonlactating state and to test for energetic adaptations in basal metabolic rate (BMR) and physical activity during the energy-demanding process of lactation. Milk production and composition, body weight and composition, TEE, BMR and physical activity levels were measured in 24 well-nourished women during exclusive breastfeeding at 3 mo postpartum and after the cessation of breastfeeding at 18 or 24 mo postpartum. TEE was measured by the doubly labeled water method, milk production by 3-d test-weighing, milk energy by bomb calorimetry on a 24-h milk sample, body composition by dual-energy x-ray absorptiometry and BMR by room respiration calorimetry. TEE, BMR and physical activity level (physical activity level = TEE/BMR) did not differ between the lactating and nonlactating state (TEE 10.0 +/- 1.5 versus 10.6 +/- 2.1 MJ/d). Mean milk energy output was equivalent to 2.02 +/- 0.33 MJ/d. Total energy requirements were greater during lactation than afterward (12.0 +/- 1.4 versus 10.6 +/- 2.1 MJ/d, P: = 0.002). Energy mobilization from tissue stores (-0.65 +/- 0.97 MJ/d) resulted in net energy requirements during lactation of 11.4 +/- 1.8 MJ/d. Because adaptations in basal metabolism and physical activity were not evident in these well-nourished women, energy requirements during lactation were met primarily from the diet and only partially by mobilization of tissue stores.

Infant feeding mode affects early growth and body composition

BACKGROUND

Differences in the growth pattern of breastfed (BF) and formula-fed (FF) infants are well-recognized and have been attributed to differences in nutrient intake. However, the impact of qualitative and quantitative differences in nutrient intake on the body composition of BF and FF infants has been unclear. Furthermore, it is unknown whether putative differences in body composition persist beyond weaning.

DESIGN

Prospective cohort study.

METHODS

Repeated anthropometric and body composition measurements were performed on 40 BF and 36 FF infants at 0.5, 3, 6, 9, 12, 18, and 24 months of age. A multicomponent body composition model based on total body water by deuterium dilution, total body potassium by whole body counting, and bone mineral content by dual-energy x-ray absorptiometry was used to estimate fat-free mass (FFM) and fat mass (FM). Independent measurements of FFM and FM were made using total body electrical conductivity and dual-energy x-ray absorptiometry. By design, infants were either exclusively BF or FF from birth to 4 months of age; thereafter, the feeding mode was at the discretion of the parents. Infant food intake was measured at 3, 6, 12, and 24 months of age using 3-day weighed-intake records. Data were analyzed by repeated measures analysis of variance.

RESULTS

Weight velocity was higher in FF than BF infants age 3 to 6 months, and higher in FF than BF girls 6 to 9 months of age. Adjusted for gender and baseline values, BF infants had lower total body water at 3 months, lower total body potassium at 3 to 24 months, and lower bone mineral content at 12 months. The multicomponent model indicated that FFM was lower in BF than FF infants at 3 months, and FM and %FM were higher in BF than FF infants at 3 and 6 months (boys only). Total body electric conductivity confirmed lower FFM in BF than FF infants at 3 months, as well as at 6 and 9 months; FM and %FM were higher in BF than FF at 3 and 6 months, and 9 months (boys only). Intakes of energy, protein, fat, and carbohydrate were lower in BF than FF infants at 3 and 6 months, and were positively correlated with weight gain and FFM gain, but not FM gain. No differences in nutrient intakes were observed at 12 or 24 months.

CONCLUSION

Infant feeding mode is associated with differences in body composition in early infancy which do not persist into the second year of life.

Energy requirements derived from total energy expenditure and energy deposition during the first 2 y of life

BACKGROUND

Current recommendations for energy intake of children are derived from observed intakes. Deriving energy requirements on the basis of energy expenditure and deposition is scientifically more rational than is using the observational approach and is now possible with data on total energy expenditure (TEE), growth, and body composition.

OBJECTIVES

The objectives of this study were 1) to define energy requirements during the first 2 y of life on the basis of TEE and energy deposition; 2) to test effects of sex, age, and feeding mode on energy requirements; and 3) to determine physical activity.

DESIGN

TEE, sleeping metabolic rate, anthropometry, and body composition were measured in 76 infants. TEE was measured with doubly labeled water, sleeping metabolic rate with respiratory calorimetry, and body composition with a multicomponent model.

RESULTS

Total energy requirements were 2.23, 2.59, 2.97, 3. 38, 3.72, and 4.15 MJ/d at 3, 6, 9, 12, 18, and 24 mo, respectively. Energy deposition (in MJ/d) decreased significantly over time (P: = 0.001) and was lower in breast-fed than in formula-fed infants (P: = 0.01). Energy requirements were approximately 80% of current recommendations. Energy requirements differed by age (P: = 0.001), feeding group (P: = 0.03), and sex (P: = 0.03). Adjusted for weight or fat-free mass and fat mass, energy requirements still differed by feeding group but not by age or sex. Temperament and motor development did not affect TEE.

CONCLUSION

The TEE and energy-deposition data of these healthy, thriving children provide strong evidence that current recommendations for energy intake in the first 2 y of life should be revised.

A quantitative competitive PCR assay for the covalently closed circular form of the duck hepatitis B virus

A crucial step in the establishment and maintenance of a hepadnavirus infection is the formation of a pool of covalently closed circular viral genomes in the nucleus. Changes in the size of this pool occur when an infection is established, when acute infections are resolved, and when chronic infections are treated with antiviral drugs. However, the lack of a quantitative assay for the cccDNA form of the virus has hampered study of the biology of this replication intermediate. In response to this need we have devised a sensitive and accurate competitive PCR assay that is highly selective for the cccDNA form of the duck hepatitis B virus. Since only small amounts of DNA are needed for the assay, cccDNA pool sizes can be monitored in live animals using DNA derived from needle biopsies of infected liver.

Estimation of body fat in Caucasian and African-American girls: total-body electrical conductivity methodology versus a four-component model

BACKGROUND

Obesity has been increasing dramatically in recent years among children, particularly African-American girls. Total-body electrical conductivity (TOBEC) is a simple way to measure body fat with minimal risk.

OBJECTIVE

This study compared the agreement between the percentage of fat mass (%FM) predicted using two TOBEC equations with %FM measured by a four-component model in 73 Caucasian and 41 African-American girls.

DESIGN AND MEASUREMENTS

%FM predicted using the TOBEC equations was compared with %FM from the four-component model based on measurements of body density, body water and bone mineral content.

RESULTS

Analyses by linear regression analysis and by the Bland and Altman methods comparison procedure showed that the equation using the square root of the TOBEC zero-order Fourier coefficient and the subject's height yielded more accurate and more reproducible %FM, regardless of race, than the TOBEC linear equation, which was based on the zero-, first- and second-order Fourier coefficients. The Bland and Altman comparison further revealed that the accuracy and limits of agreement of the TOBEC linear equation were related to body fatness among the Caucasian girls. The relationship, however, disappeared when prepubescent girls and a girl with low %FM were excluded from the analysis.

CONCLUSIONS

The TOBEC square root equation with adjustment for body geometry and length is recommended for use in adolescent girls, as it yielded better agreement with the criterion method. However, further validation of the TOBEC instrumentation for estimating body fat in prepubescent children and children with low body fat is warranted.

Loss of heterozygosity assay for molecular detection of cancer using energy-transfer primers and capillary array electrophoresis

Microsatellite DNA loci are useful markers for the detection of loss of heterozygosity (LOH) and microsatellite instability (MI) associated with primary cancers. To carry out large-scale studies of LOH and MI in cancer progression, high-throughput instrumentation and assays with high accuracy and sensitivity need to be validated. DNA was extracted from 26 renal tumor and paired lymphocyte samples and amplified with two-color energy-transfer (ET) fluorescent primers specific for loci associated with cancer-induced chromosomal changes. PCR amplicons were separated on the MegaBACE-1000 96 capillary array electrophoresis (CAE) instrument and analyzed with MegaBACE Genetic Profiler v.1.0 software. Ninety-six separations were achieved in parallel in 75 minutes. Loss of heterozygosity was easily detected in tumor samples as was the gain/loss of microsatellite core repeats. Allelic ratios were determined with a precision of +/- 10% or better. Prior analysis of these samples with slab gel electrophoresis and radioisotope labeling had not detected these changes with as much sensitivity or precision. This study establishes the validity of this assay and the MegaBACE instrument for large-scale, high-throughput studies of the molecular genetic changes associated with cancer.

Estimating body fat in African American and white adolescent girls: a comparison of skinfold-thickness equations with a 4-compartment criterion model

BACKGROUND

Although skinfold-thickness equations are widely used to estimate body fat, their accuracy in a biracial population of female adolescents has not been established.

OBJECTIVE

We undertook this study to determine the agreement between 8 widely used skinfold-thickness equations and a 4-compartment criterion model in predicting the percentage body fat of 72 white and 40 African American girls aged 13.0 +/- 1.9 y.

DESIGN

The biceps, triceps, suprailiac, subscapular, thigh, calf, and abdominal skinfold thicknesses of the subjects were measured with skinfold calipers and the buttocks circumference with a metal tape. The percentage fat mass (%FM) predicted by using each skinfold-thickness equation was compared with the criterion value calculated by the 4-compartment model on the basis of measurements of body density, body water, and bone mineral content.

RESULTS

When the racial groups were analyzed separately, the Bland-Altman analysis indicated that the quadratic equations agreed most closely with the 4-compartment model's measurement of %FM. Agreement of the other equations varied with body fatness.

CONCLUSIONS

The quadratic equation of Slaughter et al is recommended for population studies in female adolescents because of its accuracy and simplicity. However, an individual %FM can be over- or underestimated by approximately 10% when this skinfold-thickness equation is used.

High speed single nucleotide polymorphism typing of a hereditary haemochromatosis mutation with capillary array electrophoresis microplates

A single nucleotide polymorphism (SNP) typing assay is developed and evaluated on a microfabricated capillary array electrophoresis system. Using fluorescently labeled allele-specific primers, the S65C (193A-->T) substitution associated with hereditary haemochromatosis in the HFE gene is genotyped. The covalently labeled polymerase chain reaction (PCR) products are separated on a microfabricated radial capillary array electrophoresis microplate using nondenaturing gel media in under two minutes. Detection is accomplished with a laser-excited rotary confocal scanner. The Rox-labeled A-allele specific amplicon (211 bp) is differentiated from the R110-labeled T-allele specific amplicon (201 bp) by both size and color. This study demonstrates the feasibility of using allele-specific PCR with covalently labeled primers for high speed fluorescent SNP typing on microfabricated radial capillary array electrophoresis microplates.

Anthropometric estimation of maternal body composition in late gestation

OBJECTIVE

To construct a model to estimate maternal body composition in late gestation using anthropometric measurements.

METHODS

Twenty healthy pregnant women at 30 weeks' gestation had estimates of body composition using hydrodensitometry, with corrections for residual lung volume, and total body water using H(2)(18)O (development group). Total body water was estimated from (18)O abundances measured by gas-isotope-ratio mass spectrometry. Maternal age, height, weight, and seven skinfold sites were correlated with fat mass using stepwise regression analysis. The anthropometric model to estimate fat mass was then tested prospectively in a second group of 20 subjects and correlated with underwater weighing and total body water measurements (validation group). Statistical analysis used chi(2), paired t and Wilcoxon sign-rank tests.

RESULTS

There were no statistically significant differences in maternal demographics between groups. The fat mass of development group subjects using underwater weighing and total body water was 22.7 +/- 7.6 kg. Using the development group, a model was derived that explained 91% of the variance in fat mass by underwater weighing and total body water using maternal weight and triceps, subscapular, and suprailiac skinfolds (r(2) = 0.91, P <.001). When tested prospectively in the validation group, the correlation remained statistically significant (r(2) = 0.89, P <.001). There was no statistically significant (P =.88) difference between the anthropometric estimates of fat mass and underwater weighing and total body water measurements (95% confidence interval -2.476, 2.748 kg of fat mass).

CONCLUSION

This anthropometric model can be used to predict maternal fat mass in late gestation.

Using conjunctival swab with polymerase chain reaction to aid diagnosis of cytomegalovirus retinitis in AIDS patients

Conjunctival swabs were used in combination with polymerase chain reactions (PCR) or virus culture to aid to confirm the diagnosis of cytomegalovirus (CMV) retinitis in AIDS patients. Based on ophthalmoscopic findings, 13 AIDS patients were diagnosed as having CMV retinitis and treated with systemic ganciclovir from January 1997 to December 1998. Nine of 13 AIDS patients with CMV retinitis were found to be positive for CMV DNA by using a conjunctival swab with PCR (CS-PCR). CMV was also isolated from the conjunctival swab culture in 2 AIDS patients with CMV retinitis. Following 1 month of systemic ganciclovir treatment, except for 1 patient who had disease progression and remained positive for CMV DNA by using CS-PCR, 12 patients were negative for CMV with a concordant lesion regression. Results of this study also indicate that this CS-PCR method is valuable for confirming the diagnosis of CMV retinitis and monitoring the ganciclovir effect on the treatment of CMV retinitis in AIDS patients.

Body composition during the first 2 years of life: an updated reference

Normative body composition during the first 2 y of life was derived from a prospective study of 76 children. We present 1) fat free mass (FFM) and its components, and fat mass (FM), 2) incremental growth rates partitioned into chemical components, and 3) age-specific and gender-specific constants for converting chemical and physical components into FFM for children during the first 2 y of life. A multicomponent model based on measurements of total body water (TBW), total body potassium (TBK) and bone mineral content (BMC) was used to estimate FFM and FM at 0.5, 3, 6, 9, 12, 18, and 24 mo of age. TBW was determined by deuterium dilution, TBK by whole body counting, and BMC by dual energy x-ray absorptiometry. FFM was higher in boys than girls between 0.5-18 mo of age (p < or = 0.05). Percent FM increased on average from 13 to 31% between 0.5 and 3-6 mo, and then gradually declined. Percent FM was significantly higher in girls than in boys at 6 and 9 mo of age (p < or = 0.02). The components of FFM on a percentage basis changed with age (p = 0.001), but not gender. The protein content of FFM increased gradually with age, while TBW declined (p = 0.001). As a percentage of FFM, osseous mineral increased from 2.0 to 3.4% in boys and from 2.1 to 3.3% in girls between 0.5 and 24 mo (p = 0.001). Density and potassium content of FFM increased gradually with age (p = 0.001). These normative body composition data provide an updated reference upon which to assess normal growth and nutritional status of pediatric populations representative of mixed feeding groups during the first 2 y of life.

The reference child and adolescent models of body composition. A contemporary comparison

Changes in the relative proportions of bone, muscle, water, visceral tissues, and body fat occur during growth. In the 1980s, reference models of body composition for children and adolescents were constructed by adjusting data on total body water (TBW), total body potassium (TBK), and regional bone mineral (BMC) data from several different Caucasian populations. In our study, we measured TBW, TBK, and total body BMC in 856 healthy European-American, African-American, and Mexican-American children. When we reconstructed the reference models using our contemporary data, we found that the body's bone, protein, and fat compartments are slightly but significantly different from the earlier models. Our study provides the range of normal body composition of healthy children, aged 5-18 years, and accounts for differences related to gender and ethnicity.