Associations between birth size and later height from infancy through adulthood: An individual based pooled analysis of 28 twin cohorts participating in the CODATwins project

BACKGROUND

There is evidence that birth size is positively associated with height in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment.

AIM

To analyze the associations of birth weight, length and ponderal index with height from infancy through adulthood within mono- and dizygotic twin pairs, which provides insights into the role of genetic and environmental individual-specific factors.

METHODS

This study is based on the data from 28 twin cohorts in 17 countries. The pooled data included 41,852 complete twin pairs (55% monozygotic and 45% same-sex dizygotic) with information on birth weight and a total of 112,409 paired height measurements at ages ranging from 1 to 69 years. Birth length was available for 19,881 complete twin pairs, with a total of 72,692 paired height measurements. The association between birth size and later height was analyzed at both the individual and within-pair level by linear regression analyses.

RESULTS

Within twin pairs, regression coefficients showed that a 1-kg increase in birth weight and a 1-cm increase in birth length were associated with 1.14-4.25 cm and 0.18-0.90 cm taller height, respectively. The magnitude of the associations was generally greater within dizygotic than within monozygotic twin pairs, and this difference between zygosities was more pronounced for birth length.

CONCLUSION

Both genetic and individual-specific environmental factors play a role in the association between birth size and later height from infancy to adulthood, with a larger role for genetics in the association with birth length than with birth weight.

Biological effect of an alternating electric field on cell proliferation and synergistic antimitotic effect in combination with ionizing radiation

Alternating electric fields at an intermediate frequency (100~300 kHz), referred to as tumour-treating fields (TTF), are believed to interrupt the process of mitosis via apoptosis and to act as an inhibitor of cell proliferation. Although the existence of an antimitotic effect of TTF is widely known, the proposed apoptotic mechanism of TTF on cell function and the efficacy of TTF are controversial issues among medical experts. To resolve these controversial issues, a better understanding of the underlying molecular mechanisms of TTF on cell function and the differences between the effects of TTF alone and in combination with other treatment techniques is essential. Here, we report experimental evidence of TTF-induced apoptosis and the synergistic antimitotic effect of TTF in combination with ionizing radiation (IR). For these experiments, two human Glioblastoma multiforme (GBM) cells (U373 and U87) were treated either with TTF alone or with TTF followed by ionizing radiation (IR). Cell apoptosis, DNA damage, and mitotic abnormalities were quantified after the application of TTF, and their percentages were markedly increased when TTF was combined with IR. Our experimental results also suggested that TTF combined with IR synergistically suppressed both cell migration and invasion, based on the inhibition of MMP-9 and vimentin.

Abstract 838: Effect of tumor treating fields on cell proliferation and synergistic antitumor efficacy in combination with ionizing radiation

Alternating electric fields at an intermediate frequency (100~300 kHz), called tumor treating fields (TTFs), are reported to interrupt the process of mitosis via apoptosis and to act as an inhibitor of cell proliferation. Although the presence of an antimitotic effect of TTFs has been widely reported, the efficacy of TTFs is still controversial issue among medical experts. To resolve this controversial issue, the comparison study between the effects of TTFs and the effect of other conventional cancer treatment techniques need to be carried out. In this study, experimental evidence of the synergistic antimitotic effect of TTFs in combination with ionizing radiation (IR) is reported. For these experiments, aggressive brain cancer cells, glioblastoma multiforme (GBM) cells (U373 and U87), were treated either with TTFs alone, with IR alone or with TTFs followed by ionizing radiation (IR). The percentages of cell apoptosis, DNA damage, and mitotic abnormalities were increased by the application of TTFs alone and its quantity was markedly increased when TTFs were combined with IR. Our results also suggested that radiotherapy together with TTFs may be clinically beneficial since the combination treatment seemed to synergistically suppress both cell migration and invasion, based on the inhibition of MMP-9 and vimentin.

Citation Format: Eun Ho Kim, Yunhui Jo, Jiwon Sung, Hyo Sook Song, Myonggeun Yoon. Effect of tumor treating fields on cell proliferation and synergistic antitumor efficacy in combination with ionizing radiation [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 838. doi:10.1158/1538-7445.AM2017-838

Rice Bran Extract Inhibits TMEM16A-Involved Activity in the Neonatal Rat Cochlea

TMEM16A is a Ca²⁺-activated Cl⁻ channel found in secretory glands, GI and respiratory tracts, and sensory organs, playing a major physiological role in fluid secretion, autonomous GI motility, and sensory transduction. In addition, overexpression of TMEM16A has been associated with cancer cell proliferation and invasion. Suppression of upregulated TMEM16A has been proposed as an effective anti-cancer strategy. While searching for a potential TMEM16A inhibitor, components of rice bran attracted our attention due to their anti-cancer potential in colon cancer cells, a type of cells known to overexpressing TMEM16A. Here, it was tested whether rice bran extract exhibits anti-TMEM16A activity. Rice bran extract was tested in the neonatal rat cochlear tissues where TMEM16A-involved spontaneous activity is generated as a part of normal development of the auditory pathway. Rice bran extract readily inhibited the TMEM16A-involved activity in the cochlear tissues and the effect was reversible upon washout. Taken together, rice bran extract appears to contain a putative TMEM16A inhibitor and the rice byproduct might serve as a source of a new anti-cancer agent.

Secondary cancer-incidence risk estimates for external radiotherapy and high-dose-rate brachytherapy in cervical cancer: phantom study

This study was designed to estimate radiation‐induced secondary cancer risks from high‐dose‐rate (HDR) brachytherapy and external radiotherapy for patients with cervical cancer based on measurements of doses absorbed by various organs. Organ doses from HDR brachytherapy and external radiotherapy were measured using glass rod dosimeters. Doses to out‐of‐field organs were measured at various locations inside an anthropomorphic phantom. Brachytherapy‐associated organ doses were measured using a specialized phantom that enabled applicator insertion, with the pelvis portion of the existing anthropomorphic phantom replaced by this new phantom. Measured organ doses were used to calculate secondary cancer risk based on Biological Effects of Ionizing Radiation (BEIR) VII models. In both treatment modalities, organ doses per prescribed dose (PD) mostly depended on the distance between organs. The locations showing the highest and lowest doses were the right kidney (external radiotherapy: 215.2 mGy; brachytherapy: 655.17 mGy) and the brain (external radiotherapy: 15.82 mGy; brachytherapy: 2.49 mGy), respectively. Organ doses to nearby regions were higher for brachytherapy than for external beam therapy, whereas organ doses to distant regions were higher for external beam therapy. Organ doses to distant treatment regions in external radiotherapy were due primarily to out‐of‐field radiation resulting from scattering and leakage in the gantry head. For brachytherapy, the highest estimated lifetime attributable risk per 100,000 population was to the stomach (88.6), whereas the lowest risks were to the brain (0.4) and eye (0.4); for external radiotherapy, the highest and lowest risks were to the thyroid (305.1) and brain (2.4). These results may help provide a database on the impact of radiotherapy‐induced secondary cancer incidence during cervical cancer treatment, as well as suggest further research on strategies to counteract the risks of radiotherapy‐associated secondary malignancies.

PACS number(s): 87.52.‐g, 87.52.Px, 87.53.Dq, 87.53.Jw