[Value of radiomics models based on MRI diffusion weighted imaging and apparent diffusion coefficient in differentiating benign and malignant thyroid nodules].

Objective: To investigate the value of radiomics models based on magnetic resonance imaging (MRI) diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps in distinguishing benign and malignant thyroid nodules. Methods: A cross-sectional study. Clinical data of 148 thyroid nodules (50 benign, 98 malignant) from 140 patients who underwent thyroid MRI examination in Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences between January 2019 and December 2022 were retrospectively analyzed. The nodules were used as the study units, and a leave-one-out method was used to randomly divide the nodules into a training set and a test set at a 7∶3 ratio. Region of interest was segmented and radiomics features were extracted from the DWI and ADC images. In the training set, feature selection was performed using inter-observer agreement analysis, U-test, least absolute shrinkage and selection operator algorithm, and correlation analysis. Four classifiers, including support vector machine (SVM), random forest (RF), k-nearest neighbors (KNN) and logistic regression (LR) were used to build models with the selected features, including the DWI models, ADC models, and combined models. The models were independently tested in the test set. The performance of the radiomics models in distinguishing benign and malignant thyroid nodules was evaluated using the receiver operating characteristic (ROC) curve, with pathological results as the gold standard. Results: Of the 140 patients, there were 40 males and 100 females, with a mean age of (38.4±12.2) years. After feature selection, 11 DWI features and 11 ADC features were used to build the models. In the training set, the AUC values of the combined models were higher than those of the corresponding DWI and ADC models. In the test set, the SVM combined model showed the best predictive performance, with an AUC of 0.873 (95%CI:0.740-0.954), accuracy of 75.6%, sensitivity of 46.7%, specificity of 90.0%, positive predictive value (PPV) of 70.0% and negative predictive value (NPV) of 77.1%, while the RF combined model had an AUC of 0.836 (95%CI:0.695-0.929), accuracy of 77.8%, sensitivity of 40.0%, specificity of 96.7%, PPV of 85.7% and NPV of 76.3%, the KNN combined model had an AUC of 0.832 (95%CI:0.691-0.927), accuracy of 77.8%, sensitivity of 33.3%, specificity of 100%, PPV of 100% and NPV of 75.0%, the LR combined model had an AUC of 0.813 (95%CI:0.669-0.914), accuracy of 77.8%, sensitivity of 60.0%, specificity of 86.7%, PPV of 69.2% and NPV of 81.3%. Conclusions: Radiomics models based on DWI and ADC image features can effectively distinguish benign and malignant thyroid nodules. The SVM combined model had the best prediction performance.

Optimising diffusion-weighted imaging of the thyroid gland using dedicated surface coil.

AIM: To assess the feasibility of applying field-of-view (FOV) optimised and constrained undistorted single-shot (FOCUS) diffusion-weighted imaging (DWI) in the thyroid gland by comparing its image quality with conventional DWI (C-DWI) qualitatively and quantitatively using a dedicated surface coil exclusively designed for the thyroid gland at 3 T magnetic resonance imaging (MRI). MATERIALS AND METHODS: In this prospective study, 32 healthy volunteers who had undergone 3 T the thyroid gland MRI with FOCUS-DWI and C-DWI were enrolled. Two independent reviewers assessed the overall image quality, artefacts, sharpness, and geometric distortion based on a five-point Likert scale. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) were quantified for both sequences. Interobserver agreement, qualitative scores, and quantitative parameters were compared between two sequences. RESULTS: Agreement between the two readers was good for FOCUS-DWI (κ = 0.714-0.778) and moderate to good for C-DWI (κ = 0.525-0.672) in qualitative image quality assessment. Qualitatively, image quality (overall image quality, artefacts, sharpness, and geometric distortion) was significantly better in FOCUS-DWI than that in the C-DWI (all p<0.05); however, quantitatively, FOCUS-DWI had significantly lower SNRs (p<0.001) and CNRs (p=0.012) compared with C-DWI. The ADC value on FOCUS-DWI was significantly higher than that on C-DWI (p<0.001). CONCLUSION: FOCUS-DWI depicted the thyroid gland with significantly better image quality qualitatively and less ghost artefacts, but had significantly lower SNR and CNR quantitatively, compared with C-DWI, suggesting that both DWI sequences have advantages and could be chosen for different purposes.

[The efficacy of the improved tongue base suspension surgery combined with UPPP in the treatment of severe OSA].

Objective:This study was designed to show the preliminary efficacy and safety of the improved tongue base suspension surgery in severe obstructive sleep apnea(OSA) patients classified as Friedman Ⅱand Friedman Ⅲ. Method:The severe OSA patients diagnosed by PSG as Friedman Ⅱ type and Ⅲ type underwent surgery treatment. The tongue base of the patient was implanted with titanium plate and fixed on the chin of mandible. The UPPP surgery was performed with reference to H-UPPP. After surgery, the patients were followed up, PSG was re-examined and the change of various subjective and objective indicators of rehabilitation and adverse reactions were observed and recorded.Result: One hundred and two patients with severe OSA who were not tolerant or unwilling to use CPAP treatment were treated by the above surgical method. All the patients underwent surgery successfully and generally recovered about 1 month after the surgery without obvious tongue base pain, foreign body sensation or other discomfort. Eating and speaking function were as usual, the wound was healed well, and no serious infection or rejection was observed. The main postoperative adverse reactionwas tension line fracture(3 cases). Sixty-seven patients completed follow-up. At 3 to 6 months after surgery, the AHI, ESS sleepiness score and snore index were lower than those before surgery, while LSaO2and CT 90% were higher than those before surgery(P<0.01). The AHI before surgery was 60.5± 22.4, and the average AHI after surgery was 27.8± 22.4. The effective rate of the surgery was 71.6% and the success rate was 58.2%. The AHI has dropped by an average of 54.0%, and snore improved by 63.9%. Conclusion: After preliminary clinical observation, the study suggests that the improved tongue base suspension with UPPP has satisfactory curative effect and feasibility for the treatment of severe OSA patients classified as Friedman Ⅱ type and Ⅲ type.

[Efficacy of Yisaipu tapering in the treatment of ankylosing spondylitis].

Objective: To assess the efficacy of Yisaipu tapering in patients with ankylosing spondylitis (AS). Methods: A total of 87 cases of AS patients from Guangdong Second Provincial General Hospital who were treated with Yisaipu and celecoxib were retrospectively analyzed from February 2013 to April 2017.All patients received full dose Yisaipu and celecoxib in the initial 12 weeks.After that, the patients in the full dose group maintained Yisaipu (50 mg/w) treatment from the 13(rd) to 24(th) week, while tapering group received Yisaipu 50 mg subcutaneous injection once every other week.By using AS disease activity score (ASDAS), Bath AS functional index (BASFI) and magnetic resonance (MR) score of sacroiliac joint (SIJ) plus recording adverse events, differences of efficacy and safety between groups were compared. Results: ASDAS and BASFI of tapering group were 1.1±0.7 and 1.3±1.1, while those of full dose group were 1.0±0.7 and 1.1±1.0, respectively.No significant difference of ASDAS or BASFI was found between groups.Besides, the MR scores of tapering and full dose groups were 8±7 and 8±6 respectively before therapy, while they were significantly lower in the 24(th) week (4±4 and 4±3, P<0.05). However, changes of MR score between groups were similar (P>0.05). Conclusion: Dose tapering of Yisaipu subcutaneous injection might be effective for keeping stable of disease activity and function in patients with AS.Its efficacy is similar to those of full dose Yisaipu.

Effects of alendronate and strontium ranelate on cancellous and cortical bone mass in glucocorticoid-treated adult rats.

We studied the effects of alendronate (Aln) and strontium ranelate (SrR) administration on cancellous and cortical bone in glucocorticoid (GC)-treated rats. Thirty-two 3.5-month male Sprague-Dawley rats were randomized into four groups: age-matched normal control (Nrm), methylprednisolone (Met; 5.0 mg/kg/day, sc, for 5 days/week), Met plus Aln orally (1.0 mg/kg/day), and Met plus SrR orally (900 mg/kg/day). The study period was 9 weeks. DXA was used to evaluate the femoral diaphysis and fifth lumbar vertebra (L5). Histomorphometry was performed in the proximal tibial metaphysis and tibial diaphysis. Met significantly decreased body weight and bone mineral density (BMD) compared with Nrm. Aln and SrR significantly increased body weight and BMD compared with Met. SrR resulted in significantly higher BMD than Aln. Met markedly decreased BV/TV, Tb.Th, and Tb.N and increased Tb.Sp compared with Nrm. Aln and SrR showed significantly increased of BV/TV, Tb.Th, and Tb.N and improved bone architecture. Moreover, Met reduced %Ct.Ar, enlarged %Ma.Ar, and decreased bone formation indices in the periosteum as well as increased ES/BS in the endosteum compared with Nrm. Aln significantly decreased endosteal ES/BS compared with Met. SrR significantly increased %Ct.Ar and bone formation indices in the periosteum as well as the endosteum and decreased endosteal ES/BS compared with Met. Furthermore, SrR led to a significantly higher cancellous and endocortical MS/BS and endocortical bone formation compared with Aln. Our findings suggest SrR at a dose of 900 mg/kg has a greater effect than Aln at 1.0 mg/kg, according to BMD and histomorphometric analysis, in preventing GC-induced osteopenia. Therefore, SrR might be applicable as a bone therapeutic agent to treat secondary osteoporosis in the clinic.

The conserved WW-domain binding sites in Dystroglycan C-terminus are essential but partially redundant for Dystroglycan function.

BACKGROUND: Dystroglycan (Dg) is a transmembrane protein that is a part of the Dystrophin Glycoprotein Complex (DGC) which connects the extracellular matrix to the actin cytoskeleton. The C-terminal end of Dg contains a number of putative SH3, SH2 and WW domain binding sites. The most C-terminal PPXY motif has been established as a binding site for Dystrophin (Dys) WW-domain. However, our previous studies indicate that both Dystroglycan PPXY motives, WWbsI and WWbsII can bind Dystrophin protein in vitro. RESULTS: We now find that both WW binding sites are important for maintaining full Dg function in the establishment of oocyte polarity in Drosophila. If either WW binding site is mutated, the Dg protein can still be active. However, simultaneous mutations in both WW binding sites abolish the Dg activities in both overexpression and loss-of-function oocyte polarity assays in vivo. Additionally, sequence comparisons of WW binding sites in 12 species of Drosophila, as well as in humans, reveal a high level of conservation. This preservation throughout evolution supports the idea that both WW binding sites are functionally required. CONCLUSION: Based on the obtained results we propose that the presence of the two WW binding sites in Dystroglycan secures the essential interaction between Dg and Dys and might further provide additional regulation for the cytoskeletal interactions of this complex.

Notch-Delta signaling induces a transition from mitotic cell cycle to endocycle in Drosophila follicle cells.

In many developmental processes, polyploid cells are generated by a variation of the normal cell cycle called the endocycle in which cells increase their genomic content without dividing. How the transition from the normal mitotic cycle to endocycle is regulated is poorly understood. We show that the transition from mitotic cycle to endocycle in the Drosophila follicle cell epithelium is regulated by the Notch pathway. Loss of Notch function in follicle cells or its ligand Delta function in the underlying germline disrupts the normal transition of the follicle cells from mitotic cycle to endocycle, mitotic cycling continues, leading to overproliferation of these cells. The regulation is at the transcriptional level, as Su(H), a downstream transcription factor in the pathway, is also required cell autonomously in follicle cells for proper transitioning to the endocycle. One target of Notch and Su(H) is likely to be the G2/M cell cycle regulator String, a phosphatase that activates Cdc2 by dephosphorylation. String is normally repressed in the follicle cells just before the endocycle transition, but is expressed when Notch is inactivated. Analysis of the activity of String enhancer elements in follicle cells reveals the presence of an element that promotes expression of String until just before the onset of polyploidy in wild-type follicle cells but well beyond this stage in Notch mutant follicle cells. This suggests that it may be the target of the endocycle promoting activity of the Notch pathway. A second element that is insensitive to Notch regulation promotes String expression earlier in follicle cell development, which explains why Notch, while active at both stages, represses String only at the mitotic cycle-endocycle transition.

Laminin A is required for follicle cell-oocyte signaling that leads to establishment of the anterior-posterior axis in Drosophila.

The establishment of the anterior-posterior (AP) axis in Drosophila melanogaster requires signaling between the oocyte and surrounding somatic follicle cells during oogenesis [1] [2]. First, a signal from the oocyte (Gurken (Grk), a transforming growth factor-alpha (TGFalpha) homolog) is received by predetermined terminal follicle cells in which the epidermal growth factor receptor (EGFR) pathway is activated and a posterior fate is induced [2] [3] [4]. Later, the posterior follicle cells send an unidentified signal back to the oocyte, which leads to the reorganization of its cytoskeletal polarity. This reorganization is required for proper localization of maternal determinants, such as oskar (osk) and bicoid (bcd) mRNAs, that determine the AP polarity of the oocyte and the subsequent embryo [2]. We show here that when the gene lanA, which encodes the extracellular matrix component laminin A, is mutated in posterior follicle cells, localization of AP determinants is disrupted in the underlying oocyte. Posterior follicle-cell differentiation and follicle cell apical-basal polarity are unaffected in the lanA mutant cells, suggesting that laminin A is required for correct signaling from the posterior follicle cells that polarizes the oocyte. This is the first evidence that the extracellular matrix is involved in the establishment of a major body axis.

The homeobox gene mirror links EGF signalling to embryonic dorso-ventral axis formation through notch activation.

Recent studies in vertebrates and Drosophila melanogaster have revealed that Fringe-mediated activation of the Notch pathway has a role in patterning cell layers during organogenesis. In these processes, a homeobox-containing transcription factor is responsible for spatially regulating fringe (fng) expression and thus directing activation of the Notch pathway along the fng expression border. Here we show that this may be a general mechanism for patterning epithelial cell layers. At three stages in Drosophila oogenesis, mirror (mirr) and fng have complementary expression patterns in the follicle-cell epithelial layer, and at all three stages loss of mirr enlarges, and ectopic expression of mirr restricts, fng expression, with consequences for follicle-cell patterning. These morphological changes are similar to those caused by Notch mutations. Ectopic expression of mirr in the posterior follicle cells induces a stripe of rhomboid (rho) expression and represses pipe (pip), a gene with a role in the establishment of the dorsal-ventral axis, at a distance. Ectopic Notch activation has a similar long-range effect on pip. Our results suggest that Mirror and Notch induce secretion of diffusible morphogens and we have identified TGF-beta (encoded by dpp) as such a molecule in germarium. We also found that mirr expression in dorsal follicle cells is induced by the EGF-receptor (EGFR) pathway and that mirr then represses pip expression in all but the ventral follicle cells, connecting EGFR activation in the dorsal follicle cells to repression of pip in the dorsal and lateral follicle cells. Our results suggest that the differentiation of ventral follicle cells is not a direct consequence of germline signalling, but depends on long-range signals from dorsal follicle cells, and provide a link between early and late events in Drosophila embryonic dorsal-ventral axis formation.

Class VI unconventional myosin is required for spermatogenesis in Drosophila.

We have identified partial loss of function mutations in class VI unconventional myosin, 95F myosin, which results in male sterility. During spermatogenesis the germ line precursor cells undergo mitosis and meiosis to form a bundle of 64 spermatids. The spermatids remain interconnected by cytoplasmic bridges until individualization. The process of individualization involves the formation of a complex of cytoskeletal proteins and membrane, the individualization complex (IC), around the spermatid nuclei. This complex traverses the length of each spermatid resolving the shared membrane into a single membrane enclosing each spermatid. We have determined that 95F myosin is a component of the IC whose function is essential for individualization. In wild-type testes, 95F myosin localizes to the leading edge of the IC. Two independent mutations in 95F myosin reduce the amount of 95F myosin in only a subset of tissues, including the testes. This reduction of 95F myosin causes male sterility as a result of defects in spermatid individualization. Germ line transformation with the 95F myosin heavy chain cDNA rescues the male sterility phenotype. IC movement is aberrant in these 95F myosin mutants, indicating a critical role for 95F myosin in IC movement. This report is the first identification of a component of the IC other than actin. We propose that 95F myosin is a motor that participates in membrane reorganization during individualization.

The function of the broad-complex during Drosophila melanogaster oogenesis.

The Broad-Complex (BR-C) is an early ecdysone response gene that functions during metamorphosis and encodes a family of zinc-finger transcription factors. It is expressed in a dynamic pattern during oogenesis. Its late expression in the lateral-dorsal-anterior follicle cells is related to the morphogenesis of the chorionic appendages. All four zinc-finger isoforms are expressed in oogenesis, which is consistent with the abnormal appendage phenotypes resulting from their ectopic expression. We investigated the mechanism by which the BR-C affects chorion deposition by using BrdU to follow the effects of BR-C misexpression on DNA replication and in situ hybridization to ovarian mRNA to evaluate chorion gene expression. Ectopic BR-C expression leads to prolonged endoreplication and to additional amplification of genes, besides the chorion genes, at other sites in the genome. The pattern of chorion gene expression is not affected along the anterior-posterior axis, but the follicle cells at the anterior of the oocyte fail to migrate correctly in an anterior direction when BR-C is misexpressed. We conclude that the target genes of the BR-C in oogenesis include a protein essential for endoreplication and chorion gene amplification. This may provide a link between steroid hormones and the control of DNA replication during oogenesis.

Role of Notch pathway in terminal follicle cell differentiation during Drosophila oogenesis.

During Drosophila oogenesis the body axes are determined by signaling between the oocyte and the somatic follicle cells that surround the egg chamber. A key event in the establishment of oocyte anterior-posterior polarity is the differential patterning of the follicle cell epithelium along the anterior-posterior axis. Both the Notch and epithelial growth factor (EGF) receptor pathways are required for this patterning. To understand how these pathways act in the process we have analyzed markers for anterior and posterior follicle cells accompanying constitutive activation of the EGF receptor, loss of Notch function, and ectopic expression of Delta. We find that a constitutively active EGF receptor can induce posterior fate in anterior but not in lateral follicle cells, showing that the EGF receptor pathway can act only on predetermined terminal cells. Furthermore, Notch function is required at both termini for appropriate expression of anterior and posterior markers, while loss of both the EGF receptor and Notch pathways mimic the Notch loss-of-function phenotype. Ectopic expression of the Notch ligand, Delta, disturbs EGF receptor dependent posterior follicle cell differentiation and anterior-posterior polarity of the oocyte. Our data are consistent with a model in which the Notch pathway is required for early follicle cell differentiation at both termini, but is then repressed at the posterior for proper determination of the posterior follicle cells by the EGF receptor pathway.

Analysis of P[gal4] insertion lines of Drosophila melanogaster as a route to identifying genes important in the follicle cells during oogenesis.

We report the analysis of a number of lines of Drosophila melanogaster containing insertions of the yeast gal4 gene. By crossing a UAS-lacZ fusion gene as a reporter into these lines, we analysed the expression patterns of beta-galactosidase during oogenesis. Since there is no expression of GAL4 in the germ-line in these experiments, this is an ideal system for the analysis of expression patterns in sub-sets of follicle cells. These lines provide ideal markers for sets of follicle cells, e.g. anterior or posterior polar cells for studying genetic interactions in oogenesis; however, they can also be used in the same way as conventional enhancer traps to clone nearby genes with similar expression patterns. The advantages of this dual gal4/UAS system over conventional enhancer trapping includes the possibility of GAL4-directed misexpression and antisense expression studies to establish the function of the genes we identified during follicle cell determination and differentiation. These studies could lead to the isolation of homologous genes crucial in mammalian oogenesis. Understanding how the somatic cells and germ cells interact to promote growth and maturation of the mammalian follicle and oocyte could well be crucial for improving the fertility of eggs used for in-vitro fertilization programmes, and could provide methods for assessing the quality of eggs.

Two signalling pathways specify localised expression of the Broad-Complex in Drosophila eggshell patterning and morphogenesis.

The Drosophila eggshell, which has a pair of chorionic appendages (dorsal appendages) located asymmetrically along both the anterior/posterior and dorsal/ventral axes, provides a good model to study signal instructed morphogenesis. We show that the Broad-Complex, a gene encoding zinc-finger transcription factors, is essential for the morphogenesis of dorsal appendages and is expressed in a bilaterally symmetrical pattern in the lateral-dorsal-anterior follicle cells during late oogenesis. This is induced and specified along the dorsoventral axis by an epidermal growth factor receptor signalling pathway, which includes a localised transforming growth factor-alpha like molecule, Gurken, in the oocyte and the Drosophila EGF receptor homologue, Torpedo, in the surrounding somatic follicle cells. Furthermore, the precisely localised expression of BR-C along the AP axis requires a separate signalling pathway, initiated by a transforming growth factor-beta homologue, Decapentaplegic, in nearby follicle cells. These two signalling pathways, one from the oocyte and the other from the follicle cells, co-ordinately specify patches of follicle cells to express the Broad-Complex in a unique position in respect to both major axes, which in turn directs the differentiation of the dorsal appendages in the correct position on the eggshell.