Impact of carbohydrate restriction in the context of obesity on prostate tumor growth in the Hi-Myc transgenic mouse model

Introduction

Previously, we showed that carbohydrate restriction with calorie restriction slowed tumor growth in xenograft mouse prostate cancer models. Herein, we examined the impact of carbohydrate restriction without calorie restriction on tumor development within the context of diet-induced obesity in the Hi-Myc transgenic mouse model of prostate cancer.

Methods

Mice were randomized at 5 weeks of age to ad libitum Western diet (WD; 40% fat, 42% carbohydrate; n=39) or ad libitum no carbohydrate ketogenic diet (NCKD; 82% fat, 1% carbohydrate; n=44). At age 3 or 6 months, mice were sacrificed, prostates weighed and prostate histology, proliferation, apoptosis, and macrophage infiltration evaluated by H&E, Ki67, TUNEL and F4/80 staining, respectively. Body composition was assessed by DEXA, serum cytokines measured using multiplex, and Akt/mTOR signaling assessed by Western.

Results

Caloric intake was higher in the NCKD group, resulting in elevated body weights at 6 months of age, relative to the WD group (45g vs. 38g; p=0.008). Despite elevated body weights, serum MCP-1 and IL-1α levels were lower in NCKD versus WD mice (p=0.046 and p=0.118, respectively), and macrophage infiltration was reduced in prostates of NCKD versus WD mice (p=0.028). Relative Akt phosphorylation and phospho-S6 ribosomal protein levels were reduced in prostates of NCKD versus WD mice. However, while mice randomized to NCKD had smaller prostates after adjustment for body weight at 3 and 6 months (p=0.004 and p=0.002, respectively), NCKD mice had higher rates of adenocarcinoma at 6 months compared to WD mice (100% vs. 80%, p=0.04).

Conclusions

Despite higher caloric intake and elevated body weights, carbohydrate restriction lowered serum MCP-1 levels, reduced prostate macrophage infiltration, reduced prostate weight, but failed to slow adenocarcinoma development. Together, these data suggest that although carbohydrate restriction within the context of obesity may reduce obesity-associated systemic inflammation, it is not sufficient to counteract obesity-associated tumor growth.

Ablation with low-dose radioiodine and thyrotropin alfa in thyroid cancer

BACKGROUND

It is not known whether low-dose radioiodine (1.1 GBq [30 mCi]) is as effective as high-dose radioiodine (3.7 GBq [100 mCi]) for treating patients with differentiated thyroid cancer or whether the effects of radioiodine (especially at a low dose) are influenced by using either recombinant human thyrotropin (thyrotropin alfa) or thyroid hormone withdrawal.

METHODS

At 29 centers in the United Kingdom, we conducted a randomized noninferiority trial comparing low-dose and high-dose radioiodine, each in combination with either thyrotropin alfa or thyroid hormone withdrawal before ablation. Patients (age range, 16 to 80 years) had tumor stage T1 to T3, with possible spread to nearby lymph nodes but without metastasis. End points were the rate of success of ablation at 6 to 9 months, adverse events, quality of life, and length of hospital stay.

RESULTS

A total of 438 patients underwent randomization; data could be analyzed for 421. Ablation success rates were 85.0% in the group receiving low-dose radioiodine versus 88.9% in the group receiving the high dose and 87.1% in the thyrotropin alfa group versus 86.7% in the group undergoing thyroid hormone withdrawal. All 95% confidence intervals for the differences were within ±10 percentage points, indicating noninferiority. Similar results were found for low-dose radioiodine plus thyrotropin alfa (84.3%) versus high-dose radioiodine plus thyroid hormone withdrawal (87.6%) or high-dose radioiodine plus thyrotropin alfa (90.2%). More patients in the high-dose group than in the low-dose group were hospitalized for at least 3 days (36.3% vs. 13.0%, P<0.001). The proportions of patients with adverse events were 21% in the low-dose group versus 33% in the high-dose group (P=0.007) and 23% in the thyrotropin alfa group versus 30% in the group undergoing thyroid hormone withdrawal (P=0.11).

CONCLUSIONS

Low-dose radioiodine plus thyrotropin alfa was as effective as high-dose radioiodine, with a lower rate of adverse events. (Funded by Cancer Research UK; ClinicalTrials.gov number, NCT00415233.).

Thyroid cancer susceptibility polymorphisms: confirmation of loci on chromosomes 9q22 and 14q13, validation of a recessive 8q24 locus and failure to replicate a locus on 5q24

Five single nucleotide polymorphisms (SNPs) associated with thyroid cancer (TC) risk have been reported: rs2910164 (5q24); rs6983267 (8q24); rs965513 and rs1867277 (9q22); and rs944289 (14q13). Most of these associations have not been replicated in independent populations and the combined effects of the SNPs on risk have not been examined. This study genotyped the five TC SNPs in 781 patients recruited through the TCUKIN study. Genotype data from 6122 controls were obtained from the CORGI and Wellcome Trust Case-Control Consortium studies. Significant associations were detected between TC and rs965513A (p=6.35×10(-34)), rs1867277A (p=5.90×10(-24)), rs944289T (p=6.95×10(-7)), and rs6983267G (p=0.016). rs6983267 was most strongly associated under a recessive model (P(GG vs GT + TT)=0.004), in contrast to the association of this SNP with other cancer types. However, no evidence was found of an association between rs2910164 and disease under any risk model (p>0.7). The rs1867277 association remained significant (p=0.008) after accounting for genotypes at the nearby rs965513 (p=2.3×10(-13)) and these SNPs did not tag a single high risk haplotype. The four validated TC SNPs accounted for a relatively large proportion (∼11%) of the sibling relative risk of TC, principally owing to the large effect size of rs965513 (OR 1.74).

Evaluation of a commercial rRNA amplification assay for direct detection of Mycobacterium tuberculosis in processed sputum

A commercial assay (Amplified Mycobacterium tuberculosis Direct Test, Gen Probe) which combines transcription-mediated amplification of target rRNA with amplicon detection by a chemiluminescent DNA probe for the rapid detection of Mycobacterium tuberculosis in sputum was evaluated. The test was applied to consecutively collected, NALC/NaOH processed sputum sediments from two laboratories (H and L), each serving a different population of patients with pulmonary tuberculosis. Results were compared to those of fluorochrome staining and culture. A total of 760 specimens obtained from 246 patients were used for the study. The test was positive in 141 of 144 (98%) specimens that were fluorochrome-positive and culture-positive for Mycobacterium tuberculosis. Fifteen of 31 specimens that were fluorochrome-negative, culture-positive were also assay-positive. A total of 312 specimens (100 patients) from laboratory H (prevalence = 10%) and 448 specimens (146 patients) from laboratory L (prevalence = 34%) were analyzed. Compared to culture, test sensitivity, specificity, positive predictive and negative predictive values were 65%, 99%, 94% and 97%, respectively, for laboratory H and 93%, 99%, 99% and 97%, respectively, for laboratory L. If the results were analyzed on the basis of at least one concordant result between the amplification assay and culture in three sputum samples per patient, then the sensitivity, specificity, positive and negative predictive values for identifying infected patients was 70%, 99%, 87% and 97%, respectively, for laboratory H, and 100%, 98%, 96% and 100%, respectively, for laboratory L.

Adaptation in adolescence: the influence of time and severe psychiatric disorder

This study reports the development of adaptive processes in two groups of adolescents assessed initially and 2 years later with clinical research interviews. Students from a public high school (N = 44) and inpatients on an adolescent psychiatric ward (N = 51) formed the two subject groups. The psychiatrically hospitalized group had significantly improved scores after a 2-year interval on four of six adaptive process Summary Scales: Task Orientation, Relatedness, Self Knowledge, and Inner Synthetic Functions. However, these higher scores did not reach the levels of the high school group at either point of assessment. The scores in the high school group remained stable over time except for an increase in the area of Self Knowledge. The value of this interview-derived assessment, in comparison to other forms of measurement, is discussed, and consideration is given to factors which contribute to the differences between groups.