A tail's tale: Biomechanical roles of dorsal thoracic spine of barnacle nauplii

Many marine invertebrates have complex life histories that begin with a planktonic larval stage. Similar to other plankton, these larval invertebrates often possess protruding body extensions, but their function beyond predator deterrence is not well-documented. For example, the planktonic nauplii of crustaceans have spines. Using the epibiotic pedunculate barnacle Octolasmis spp., we investigated how the dorsal thoracic spine affects swimming and fluid disturbance by comparing nauplii with their spines partially removed against those with intact spines. Our motion analysis showed that amputated Octolasmis spp. swam slower, in jerkier trajectories, and were less efficient per stroke cycle than those with intact spines. Amputees showed alterations in limb beat pattern: larger beat amplitude, increased phase lag, and reduced contralateral symmetry. These changes might partially help increase propulsive force generation and streamline the flow, but were insufficient to restore full function. Particle image velocimetry further showed that amputees had a larger relative area of influence, implying elevated risk by rheotactic predator. Body extensions and their interactions with limb motion play important biomechanical roles in shaping larval performance, which likely influences the evolution of form.

Evolution of Feeding Shapes Swimming Kinematics of Barnacle Naupliar Larvae: A Comparison between Trophic Modes

A central goal in evolutionary biology is connecting morphological features with ecological functions. For marine invertebrate larvae, appendage movement determines locomotion, feeding, and predator avoidance ability. Barnacle larvae are morphologically diverse, and the morphology of non-feeding lecithotrophic nauplii are distinct from those that are planktotrophic. Lecithotrophic larvae have a more globular body shape and simplified appendages when compared with planktotrophs. However, little is known about whether and how such morphological changes affect kinematics, hydrodynamics, and ecological functions. Here, we compared the nauplii kinematics and hydrodynamics of a lecithotrophic Rhizocephalan species, Polyascus planus, against that of the planktotrophic nauplii of an intertidal barnacle, Tetraclita japonica. High-speed, micro-particle image velocimetry analysis showed that the Polyascus nauplii swam faster and had higher amplitude and more synchronous appendage beating than the Tetraclita nauplii. This fast swimming was accompanied by a faster attenuation of induced flow with distance, suggesting reduced predation risk. Tetraclita nauplii had more efficient per beat cycles with less backward displacement during the recovery stroke. This "anchoring effect" resulted from the anti-phase beating of appendages. This movement, together with a high-drag body form, likely helps direct the suction flow toward the ventral food capturing area. In sum, the tradeoff between swimming speed and predation risks may have been an important factor in the evolution of the observed larval forms.

Correction: FOXO3a represses VEGF expression through FOXM1-dependent and -independent mechanisms in breast cancer

In the published version of this article, the images for cytoplasmic and nuclear FGF7 in MDA-MB-231 cells were duplicated and mistaken for total FGF7 in SKBR-3 and MDA-MB-231 cells.

Factors associated with common and atypical chromosome abnormalities after positive combined first-trimester screening in Chinese women: a retrospective cohort study

BACKGROUND

When cell-free DNA (cfDNA) testing is used as a secondary screening tool following combined first-trimester screening (cFTS), cFTS is used to estimate the prior risk for chromosome abnormalities. This study aimed to assess the factors that are associated with common and atypical abnormalities following cFTS, including cFTS risk, advanced maternal age, increased nuchal translucency (NT) ≥3.5 mm, and abnormal levels of serum markers.

METHODS

We reviewed a historical cohort of 1855 Chinese women carrying singleton pregnancies with a positive cFTS [at a threshold of 1:250 for trisomy (T) 21 or 1:180 for T18] in one public hospital over a five-year period. All chromosome abnormalities were confirmed by invasive prenatal diagnosis (IPD) with karyotyping, with or without array comparative genomic hybridization. Using multivariable binary logistic regression analysis, we determined the parameters that were associated with common and atypical abnormalities.

RESULTS

Overall, the prevalence of common and atypical abnormalities was 6.2 and 1.2%, respectively, and the prevalence increased with the risk of T21 by cFTS. In pregnancies with a risk of T21 > 1 in 100, a high risk of both T21 and T18, an increased NT, or a pregnancy-associated plasma A (PAPP-A) level <  0.2 multiple of medians (MoM), the prevalence of common abnormalities was 12.2, 64.7, 25.5 and 33.8%, respectively, while that of atypical abnormalities was 1.6, 3.9, 4.2, and 7.4%, respectively. In the multivariable binary logistic regression analysis, out of these four factors, only two (increased NT and PAPP_A <  0.2 MoM) were significant predictors of common and atypical abnormalities, respectively. Of all positive cFTS pregnancies, 50.4% did not have any of these four factors, and the prevalence of common and atypical abnormalities was 1.1 and 0.6%, respectively. There were three atypical abnormalities, all of which were mosaicism, and they were detected among women with IPD alone. The ages of these women were ≥ 35 years. All three pregnancies were continued after proper counseling. After giving birth, only one child had mild abnormalities, while the other two were phenotypically normal.

CONCLUSIONS

Our study identified factors associated with common and atypical abnormalities after cFTS. These factors can be used to estimate the prior risk for these abnormalities to help with post-cFTS counseling in terms of choosing between cfDNA testing and IPD.

A multidisciplinary rehabilitation programme for patients with chronic low back pain: a prospective study

PURPOSE

To examine the effectiveness of a multidisciplinary rehabilitation programme for patients with chronic low back pain in Hong Kong, and to identify factors associated with work resumption.

METHODS

57 men and 8 women aged 20 to 56 (mean, 39) years who had a more than 3-month history of low back pain and were unresponsive to more than 6 months of conventional treatment participated in a 14-week multidisciplinary rehabilitation programme involving physical conditioning, work conditioning, and work readiness. Training protocols entailed flexibility and endurance training, hydrotherapy, weight lifting, and work stimulation. Patients were assessed at baseline (week 1), week 7, week 14, and month 6 with regard to the intensity of low back pain, self-perceived disability, range of lumbar motion, isoinertial performance of the trunk muscles, and depression level. Patient demographics that influenced work resumption were identified using a prediction model. Patients who did and did not return to work were compared.

RESULTS

Of the 54 patients who completed all follow-up assessments, 28 returned to work and 26 did not. The latter was significantly older (37 vs. 42 years, p=0.038) and absent from work longer (11 vs. 22 months, p=0.029) than the former. The rehabilitation programme helped patients regain physical function and the ability to work. Patients who returned to work showed greater improvement in self-perceived disability and physical function.

CONCLUSION

This rehabilitation programme facilitated regain of physical functioning and the ability to return to work. The pre-programme employment status, duration of absence from work, and patient age were the most important predictors for work resumption.

Activated Stat3 expression in gestational trophoblastic disease: correlation with clinicopathological parameters and apoptotic indices

AIMS

To assess the expression profile of the activated form of signal transducer and activator of transcription (Stat)3 in gestational trophoblastic disease (GTD) and correlate the findings with clinicopathological parameters.

METHODS AND RESULTS

By immunohistochemistry, both cytoplasmic and nuclear expression of p-Stat3-Ser(727) was demonstrated in 88 trophoblastic tissues, including placentas and GTD. Nuclear immunoreactivity of p-Stat3-Ser(727) was significantly higher in hydatidiform mole (HM) (P < 0.001) and choriocarcinoma (P = 0.009) when compared with normal placentas. Placental site trophoblastic tumours (PSTT) and epithelioid trophoblastic tumours (ETT) also demonstrated higher nuclear p-Stat3-Ser(727) expression than their normal trophoblast counterparts. Higher p-Stat3-Ser(727) expression was confirmed in choriocarcinoma cell lines, JEG-3 and JAR, than in a normal trophoblast cell line, with both nuclear and cytoplasmic fractions demonstrated by immunoblotting. Spontaneously regressed HM showed significantly increased nuclear and cytoplasmic p-Stat3-Ser(727) immunoreactivity over those that developed gestational trophoblastic neoplasia (GTN) (P = 0.013, P = 0.039). There was a significant positive and inverse correlation between nuclear p-Stat3-Ser(727) immunoreactivity and apoptotic indices [terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labelling and M30 CytoDeath antibody] (P = 0.001, P < 0.001, Spearman's rho test) and Bcl-2 expression (P = 0.034), respectively.

CONCLUSIONS

p-Stat3-Ser(727) plays a role in the pathogenesis of GTD, probably through the regulation of apoptosis. p-Stat3-Ser(727) immunoreactivity is a potential marker in predicting GTN in HM.

Characterization of the pathogenic mechanism of a novel BRCA2 variant in a Chinese family

INTRODUCTION

Germline mutations of BRCA1 and BRCA2 account for the majority of hereditary breast cancers, many of which are classified as variants of unknown significance (VUS). We report the identification of a novel BRCA2 variant (c.7806-9T > G) in a Chinese family with multiple breast cancers and document it as a pathogenic mutation.

METHODS

The proband in this family was diagnosed with breast cancer at age 50 with a strong family history of breast cancer. DNA and RNA were extracted from the blood of the proband and her family, and was used for BRCA gene mutation/deletion screening and RNA splicing analysis.

RESULTS

BRCA2 c.7806-9T > G was identified in the proband, which was suggestive of a variant. This change was also found in two sisters of the proband with a history of breast cancer, as well as from the proband's maternal gastric cancer. The only sibling free of breast cancer did not carry the BRCA2 variant, thus demonstrating that the mutation segregates with the clinical phenotype in this family. RNA analysis on the proband blood sample revealed three aberrant splicing variants: c.7806_7874del, c.7806_7976del, and c.7806-8_7806-1ins. The latter causes a frameshift and creates a truncated protein, whilst the other two splicing variants resulted in shorter forms of the protein.

CONCLUSIONS

The identified BRCA2 c.7806-9T > G [Genbank: DQ889340] was found to be pathogenic, based on aberrant splicing events resulting in the formation of truncated protein products. Thus, better understanding and classification of BRCA variants as neutral or disease causing has important implications for genetic counseling so that appropriate management can be given.

Single nucleotide polymorphisms of follicle-stimulating hormone receptor are associated with ovarian cancer susceptibility

Epidemiological studies suggested that ovulation was associated with ovarian carcinogenesis. Follicle-stimulating hormone (FSH) played an important role in follicular development and was recently found to affect growth of ovarian epithelial cells. Single nucleotide polymorphisms (SNPs) Thr307Ala and Asn680Ser were two non-synonymous variations in the coding region of the FSH receptor (FSHR) gene. This hitherto first case-control study investigating the association between these two FSHR SNPs and the risk of ovarian cancer involved 202 histopathologically confirmed ovarian cancer patients and 266 age-matched cancer-free control subjects using restriction fragment length polymorphism assay and direct sequencing. Our results demonstrated that the 307Ala and 680Ser carriers were associated with significantly increased risk of developing serous and mucinous types of ovarian cancers (P < 0.0005, OR = 2.60, 95% CI = 1.56-4.34; and P < 0.0005, OR = 2.89, 95% CI = 1.73-4.84, adjusted for age, respectively) but not endometrioid and clear cell types. The two SNPs were found to be in modest linkage disequilibrium, D' = 0.804 and 0.701, r2 = 0.581 and 0.406 for the cancer and control groups, respectively. The major haplotype of 307Ala-680Ser was also associated with higher cancer risk (P = 0.033, OR = 1.39, 95% CI = 1.03-1.88), especially for the serous and mucinous carcinomas (P = 0.001, OR = 1.82, 95% CI = 1.27-2.60). Our results suggested that the two FSHR SNPs might affect the susceptibility of women to specific subtypes of ovarian cancer. Different types of ovarian cancer might adopt distinct carcinogenetic pathways. Such understanding may be important in selecting patients for ovulation induction therapy.

Caspase activity is downregulated in choriocarcinoma: a cDNA array differential expression study

BACKGROUND

Placental trophoblast can be considered to be pseudomalignant tissue and the pathogenesis of gestational trophoblastic diseases remains to be clarified.

AIMS

To examine the role of caspases 8 and 10, identified by differential expression, on trophoblast tumorigenesis.

METHODS

cDNA array hybridisation was used to compare gene expression profiles in choriocarcinoma cell lines (JAR, JEG, and BeWo) and normal first trimester human placentas, followed by confirmation with quantitative real time polymerase chain reaction and immunohistochemistry. Caspase 10 and its closely related family member caspase 8 were analysed.

RESULTS

Downregulation of caspase 10 in choriocarcinoma was detected by both Atlastrade mark human cDNA expression array and Atlastrade mark human 1.2 array. Caspase 10 mRNA expression was significantly lower in hydatidiform mole (p = 0.035) and chorioarcinoma (p = 0.002) compared with normal placenta. The caspase 8 and 10 proteins were expressed predominantly in the cytotrophoblast and syncytiotrophoblast, respectively, with significantly lower expression in choriocarcinomas than other trophoblastic tissues (p < 0.05). Immunoreactivity for both caspase 8 and 10 correlated with the apoptotic index previously assessed by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (p = 0.02 and p = 0.04, respectively) and M30 (p < 0.001 and p = 0.003, respectively) approaches.

CONCLUSIONS

These results suggest that the downregulation of capases 8 and 10 might contribute to the pathogenesis of choriocarcinoma.

Id helix-loop-helix proteins are differentially expressed in gestational trophoblastic disease

AIMS

To assess the expression of Id proteins in trophoblastic tissues and to correlate this with clinical parameters, proliferative and apoptotic indices as well as to related oncogene expression.

METHODS AND RESULTS

Immunohistochemistry for Id1, Id2, Id3 and Id4 was performed on 83 trophoblastic tissues including 17 normal first-trimester placentas, seven term placentas, 47 hydatidiform moles (HM), and 12 spontaneous miscarriages. The four Id proteins were predominantly expressed in the villous and implantation site intermediate trophoblast. Expression of Id1 in HM was significantly higher than that in normal placenta (P = 0.0006) and spontaneous miscarriage (P = 0.0001) but did not correlate with subsequent development of gestational trophoblastic neoplasia (GTN). Id1 expression correlated with the proliferation index as assessed by MCM7 (P = 0.003) and Ki67 (P = 0.017) and with the apoptotic activity assessed by TUNEL (P = 0.001) and M30 CytoDeath antibody (P = 0.013). Moreover, the expression of Id1 correlated with the expression of p53 (P = 0.004), p21(WAF1) (/CIP1) (P = 0.003) but not with p16 (P = 0.107).

CONCLUSIONS

Id proteins may play a role in the regulation of proliferative and apoptotic activity in trophoblastic tissue and are potentially useful in differentiating molar and non-molar gestation, but are not helpful in predicting GTN.

Replicative MCM7 protein as a proliferation marker in endometrial carcinoma: a tissue microarray and clinicopathological analysis

AIMS

To assess, in tissue microarray (TMA), the proliferative activity of endometrial carcinoma using one of the minichromosome maintenance (MCM) proteins (MCM7), and to explore its potential value for prognosis. MCM proteins are essential for eukaryotic DNA replication and have recently been used to define the proliferative compartments in human tissues.

METHODS AND RESULTS

Immunohistochemistry for MCM7 and Ki67 was performed on TMAs constructed from 212 cases of endometrial carcinoma. MCM7 and Ki67 expression was quantified according to the extent of nuclear staining. An analysis was carried out of the association between MCM7 expression and that of Ki67 and the clinicopathological characteristics of endometrial carcinoma. MCM7 and Ki67 immunoreactivity was clearly evident in the nuclei of tumour cells. MCM7 and Ki67 labelling indices in endometrial carcinomas correlated with each other (P < 0.001). A significant correlation existed between the MCM7 labelling index and histological grade (P = 0.008) and patients' age at diagnosis (P < 0.001). Well-differentiated carcinomas and younger patients had a lower MCM7 index. Poor survival was observed in patients with endometrial carcinoma with a high MCM7 index (P = 0.03) and MCM7 was found to be an independent prognostic factor by multivariate analysis (P = 0.04). The Ki67 labelling index correlated with histological grade (P = 0.01) but had no significant prognostic impact (P = 0.50).

CONCLUSIONS

In this TMA study on endometrial carcinoma, MCM7 was found to be a more reliable and useful marker than Ki67 in assessing tumour proliferation and in the prognosis of patients.

Detection of hypermethylated genes in tumor and plasma of cervical cancer patients

OBJECTIVE

The aim of this study is to investigate the prevalence of promotor CpG island methylation of the death-associated protein kinase (DAPK), p16, and O(6)-methylguanine-DNA methyltransferase (MGMT) genes in both tumor and plasma samples of cervical cancers.

METHODS

Methylation-specific PCR (MSP) was employed to detect promotor CpG island methylation of the DAPK, p16, and MGMT genes in 85 surgical tumor tissue samples and 40 pretreatment plasma samples from cervical cancers.

RESULTS

Promotor CpG island methylation of DAPK, p16, and MGMT was detectable, respectively, in 60%, 28.2%, and 18.8% of cases of cervical tumor DNA; and in 40%, 10%, and 7.5% of cases of patients' plasma DNA. Moreover, at least one of the three methylated genes was detected in 75.3% (64/85) of cases of tumor and in 55% (22/40) of cases of plasma. Higher prevalence of methylation of DAPK was found in squamous cell carcinoma than in adenocarcinoma in both univariate and multivariate analysis. Methylation of p16 was significantly associated with that of MGMT in both univariate and multivariate analysis. The methylation pattern in primary tumor and plasma was found to be concordant in 23 patients with matched tissue and plasma samples. In cases positive for DAPK and p16 methylation in tumor, detection in the paired plasma sample was 64.3% (9/14) and 33.3% (3/9), respectively.

CONCLUSIONS

Promotor CpG island methylation is a frequent event in cervical carcinogenesis. Detection of the methylated sequences in the circulation suggests that plasma DNA methylation warrants further study to determine its potential role in cancer management.

Methylation status and expression of E-cadherin and cadherin-11 in gestational trophoblastic diseases

The clinical significance of cadherins in gestational trophoblastic diseases (GTD) is not fully understood. In this study, the expression of E-cadherin and cadherin-11 in 12 normal placentas, 32 cases of hydatidiform mole (HM) including 15 complete HMs and 17 partial HMs, and five choriocarcinomas was investigated by immunohistochemistry and correlated with follow-up of HMs. Cases with available frozen blocks were further analyzed by western blot and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). Methylation of E-cadherin was investigated by methylation-specific PCR in six normal first trimester placentas, 19 HMs and their associated deciduas. E-cadherin expression was localized to cytotrophoblast and intermediate trophoblast whereas cadherin-11 was expressed in syncytiotrophoblast, intermediate trophoblast, and decidua. Immunoreactivity of E-cadherin was reduced in choriocarcinoma and complete HM when compared with that in normal first trimester placenta (P < 0.01, P = 0.04). Hypermethylation of E-cadherin was demonstrated in three complete HMs with the lowest level of E-cadherin. Compared with normal first trimester placenta, immunoreactivity of cadherin-11 was higher in complete HM (P = 0.02), but lower in choriocarcinoma (P = 0.02). Such differential expression was confirmed by western blot and semiquantitative RT-PCR. No obvious association was observed between the development of persistent trophoblastic disease with the expression of E-cadherin and cadherin-11.

Minichromosome maintenance protein 7 expression in gestational trophoblastic disease: correlation with Ki67, PCNA and clinicopathological parameters

AIMS

To assess the proliferative activity of gestational trophoblastic disease (GTD) using one of the novel proliferation markers (MCM7) and to determine its prognostic value in hydatidiform mole (HM).

METHODS AND RESULTS

Immunohistochemical staining for MCM7 was performed on 122 samples of paraffin-embedded trophoblastic tissues including 22 normal first-trimester placentas, 12 term placentas, 12 spontaneous miscarriages (SM), 21 partial moles (PM), 44 complete hydatidiform moles (CM), and 11 choriocarcinomas (CCA). The correlations between the proliferative indices assessed by MCM7, proliferating cell nuclear antigen (PCNA) and Ki67 (MIB1) immunoreactivity as well as clinical progress were assessed. MCM7 immunoreactivity was found predominantly in the nuclei of cytotrophoblast and intermediate trophoblast and decreased with placental maturation. MCM7 expression was highest in CCA, followed by CM, PM, normal first-trimester placenta, SM and term placenta. MCM7 index was significantly higher in PM and CM than in SM (P = 0.007, P < 0.001) but not between PM and CM themselves (P = 0.560). Eighteen of the 65 patients with HM developed persistent trophoblastic disease (PTD) requiring chemotherapy. There was no significant difference in MCM7 indices between the patients who developed PTD and those who did not (P = 0.312). MCM7 indices correlated well with Ki67 (P = 0.002) but not with PCNA (P = 0.054) indices. MCM7 indices demonstrated less variability than PCNA and Ki67 and may be a better proliferation marker than the latter two.

CONCLUSIONS

We conclude that MCM7 is useful in differentiating molar and non-molar gestations but is not helpful in discriminating PM from CM or in predicting PTD.