ROC study and SUV threshold using quantitative multi-modal SPECT for bone imaging

Background

We investigated the clinical performance of a quantitative multi-modal SPECT/CT reconstruction platform for yielding radioactivity concentrations of bone imaging with ^99mTc-methylene diphosphonate (MDP) or ^99mTc-dicarboxypropane diphosphonate (DPD). The novel reconstruction incorporates CT-derived tissue information while preserving the delineation of tissue boundaries. We assessed image-based reader concordance and confidence, and determined lesion classification and SUV thresholds from ROC analysis.

Methods

Seventy-two cancer patients were scanned at three US and two German clinical sites, each contributing two experienced board-certified nuclear medicine physicians as readers. We compared four variants of the reconstructed data resulting from the Flash3D (F3D) and the xSPECT Bone™ (xB) iterative reconstruction methods and presented images to the readers with and without a fused CT, resulting in four combinations. We used an all-or-none approach for inclusion, compiling results only when a reader completed all reads in a subset. After the final read, we conducted a “surrogate truth” reading, presenting all data to each reader. For any remaining discordant lesions, we conducted a consensus read. We next undertook ROC analysis to determine SUV thresholds for differentiating benign and lesional uptake.

Results

On a five-point rating scale of image quality, xB was deemed better by almost two points in resolution and one point better in overall acceptance compared to F3D. The absolute agreement of the rendered decision between the nine readers was significantly higher with CT information either inside the reconstruction (xB, xBCT) or simply through image fusion (F3DCT): 0.70 (xBCT), 0.67 (F3DCT), 0.64 (xB), and 0.46 (F3D). The confidence level to characterize the lesion was significantly higher (3.03x w/o CT, 1.32x w/CT) for xB than for F3D. There was high correlation between xB and F3D scores for lesion detection and classification, but lesion detection confidence was 41% higher w/o CT, and 21% higher w/CT for xB compared to F3D. Without CT, xB had 6.6% higher sensitivity, 7.1% higher specificity, and 6.9% greater AUC compared to F3D, and similarly with CT-fusion. The overall SUV-criterion (SUV_c) of xB (12) exceeded that for xSPECT Quant™ (xQ; 9), an approach not using the tissue delineation of xB. SUV critical numbers depended on lesion volume and location. For non-joint lesions > 6 ml, the AUC for xQ and xB was 94%, with SUV_c > 9.28 (xQ) or > 9.68 (xB); for non-joint lesions ≤ 6 ml, AUCs were 81% (xQ) and 88% (xB), and SUV_c > 8.2 (xQ) or > 9.1 (xB). For joint lesions, the AUC was 80% (xQ) and 83% (xB), with SUV_c > 8.61 (xQ) or > 13.4 (xB).

Conclusion

The incorporation of high-resolution CT-based tissue delineation in SPECT reconstruction (xSPECT Bone) provides better resolution and detects smaller lesions (6 ml), and the CT component facilitates lesion characterization. Our approach increases confidence, concordance, and accuracy for readers with a wide range of experience. The xB method retained high reading accuracy, despite the unfamiliar image presentation, having greatest impact for smaller lesions, and better localization of foci relative to bone anatomy. The quantitative assessment yielded an SUV-threshold for sensitively distinguishing benign and malignant lesions. Ongoing efforts shall establish clinically usable protocols and SUV thresholds for decision-making based on quantitative SPECT.

[Application of optical coherence tomography angiography in evaluation of retinal microvascular changes in patients with obstructive sleep apnea syndrome]

Objective: To assess the changes of retinal microvasculature in patients with obstructive sleep apnea syndrome (OSAS) evaluated by optical coherence tomography (OCTA). Methods: Adult OSAS patients who visited Beijing Tongren Hospital from Jan 2016 to Apr 2016 and complained of snoring were included in this study. The patients' general information, results of polysomnography, and OCTA parameters were collected. Patients were divided into three groups according to their apnea hypopnea index (AHI) results: Mild-moderate group, AHI≤30/h; Severe group, 30/h<AHI≤60/h; Extremely severe group, AHI>60/h, and clinical characteristics, polysomnography and OCTA parameters among the three groups were compared. Results: A total of 27 patients were included in this study with 21 males (77.8%) and 6 females (22.2%). Mean age was (41.7±10.0) years, and the mean body mass index was (27.9±4.5) kg/m(2;) Neck circumference was 31-48 cm, mean (39.8±4.3) cm; 8 patients (29.6%) suffered from hypertension that could be controlled; Epworth sleepiness scale scored 1-18 points and mean (8.5±4.4) scores; AHI ranged between 5.5 and 92.1/h with a mean of (46.4±28.6)/h. There were 9 (33.3%), 7 (25.9%), and 11 (40.7%) patients in mild-moderate group, severe group, and extremely severe group, respectively. Compared with severe group, the optic nerve head and radial peripapillary capillaries (RPC) peripapillary vascular density in extremely severe group were significantly decreased (62.4%±1.9% vs 60.3%±1.9%, P=0.041; 64.7%±1.7% vs 62.2%±2.3%, P=0.036). Conclusions: OCTA has rapid, safe, and objective characteristics in assessing the retinal microvascular changes in OSAS patients. Retinal microvascular damage in patients with OSAS is associated with the disease severity. Reduction of retinal microvascular density in patients with OSAS may be associated with intermittent hypoxia.

[Joint effect of smoking and diabetes on stroke]

Objective: To explore the interaction of smoking and diabetes on stroke. Methods: In this case-control study, a face to face questionnaire survey was conducted. Logistic regression models were used to analyze the relationship between smoking or diabetes and stroke. The indicators of interaction were calculated according to the Bootstrap method in this study. Results: A total of 918 cases and 918 healthy controls, who participated in the chronic disease risk factor survey in Xuzhou in 2013, were included in this study. Logistic regression analysis found that cigarette smoking was associated with stroke (OR=1.63, 95%CI: 1.33-2.00), and diabetes was also associated with stroke (OR=2.75, 95%CI: 2.03-3.73) after adjusting confounders. Compared with those without diabetes and smoking habit, the odds ratio of stroke in those with diabetes and smoking habits was 8.94 (95%CI:3.77-21.19). Diabetes and smoking combined interaction index was 3.65 (95%CI: 1.68-7.94), the relative excess risk was 5.77 (95%CI: 0.49-11.04), the attributable proportion was 0.65 (95%CI: 0.42-0.87). Conclusion: The results suggest that there are additive interactions between smoking and diabetes on stroke.

Metallic Hyperdensity Sign on Noncontrast CT Immediately after Mechanical Thrombectomy Predicts Parenchymal Hemorrhage in Patients with Acute Large-Artery Occlusion

BACKGROUND AND PURPOSE

Parenchymal hemorrhage is a severe complication following mechanical recanalization in patients with acute ischemic stroke with large-vessel occlusion. This study aimed to assess whether the metallic hyperdensity sign on noncontrast CT performed immediately after mechanical thrombectomy can predict parenchymal hemorrhage at 24 hours.

MATERIALS AND METHODS

We included consecutive patients with acute ischemic stroke with large-vessel occlusion who underwent noncontrast CT immediately after mechanical thrombectomy between January 2014 and September 2018. The metallic hyperdensity sign was defined as a nonpetechial intracerebral hyperdense lesion (diameter, ≥1 cm) in the basal ganglia and a maximum CT density of >90 HU. The sensitivity, specificity, and positive and negative predictive values of the metallic hyperdensity sign in predicting parenchymal hemorrhage were calculated.

RESULTS

A total of 198 patients were included. The metallic hyperdensity sign was found in 59 (29.7%) patients, and 51 (25.7%) patients had parenchymal hemorrhage at 24 hours. Patients with the metallic hyperdensity sign are more likely to have parenchymal hemorrhage than those without it (76.3% versus 4.3%, P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of the metallic hyperdensity sign in predicting parenchymal hemorrhage were 88.2%, 90.5%, 76.3%, and 95.7%, respectively.

CONCLUSIONS

The presence of the metallic hyperdensity sign on noncontrast CT performed immediately after mechanical thrombectomy in patients with large-vessel occlusion could predict the occurrence of parenchymal hemorrhage at 24 hours, which might be helpful in postinterventional management within 24 hours after mechanical thrombectomy.

Morphometry of the normal retinal periarteral capillary-free zone and changes during severe nonproliferative diabetic retinopathy

PURPOSE

To explore the normal morphological features of the retinal periarteral capillary free zone (paCFZ) and the changes associated with severe non-proliferative diabetic retinopathy (NPDR) by optical coherence tomography angiography (OCTA).

METHODS

A total of 148 normal subjects and 115 patients with severe NPDR were enrolled. Spectral-domain OCTA was used to acquire the image with a Cirrus prototype. Diameter and area of each paCFZ quadrant and adjacent large artery diameter was estimated.

RESULTS

In healthy subjects, the maximum width of paCFZ in the temporal quadrant (169.38 ± 19.26 μm) was smaller than the other three quadrants (all P <0.001). The ratio of maximum paCFZ width to artery caliber was much larger in the nasal quadrants than the rest quadrants (Ps <0.05). In patients with severe NPDR, both maximum width and area of paCFZ were significant larger, and the retinal artery inner diameters significant smaller in each quadrant compared to normal subjects (Ps <0.05). The ratio of paCFZ maximum width to artery caliber maximum width was significant greater, and the ratio of paCFZ area to artery caliber was significantly higher in all quadrants compared to normal eyes (Ps <0.05).

CONCLUSIONS

OCTA provides noninvasive and quantitative measurement of paCFZ dimensions. The maximum width and area of paCFZ quadrants and the ratios of these parameters to adjacent inner artery width and area are elevated in severe NPDR, suggesting that changes in paCFZ dimension can be used as clinical indices for diseases associated with changes in retinal microcirculation and oxygen pressure.PRÉCIS:Optical coherence tomography angiography revealed differences in retinal periarteral capillary free zone (paCFZ) morphometry between health retina and severe non-proliferative diabetic retinopathy. Morphometric indices of paCFZ may be useful for monitoring disease occurrence and progression.

[Analysis of differential gene expressions of inflammatory and repair-related factors in chronic refractory wounds in clinic]

Objective: To compare the tissue morphology and gene expressions of inflammatory and repair-related factors in chronic refractory wound tissue including pressure ulcers and diabetic feet. Methods: During August 2016 to September 2017, 10 samples of prepuce were collected after circumcision of 10 urological patients [all male, aged (38±4) years old] admitted in the First Affiliated Hospital of Nanchang University and included in normal skin group, samples of tissue around the edge of wounds with blood supply were collected from 9 heat or electric burn patients [6 male patients, 3 female patients, aged (51±8) years old], 13 pressure ulcer patients [9 male patients, 4 female patients, aged (51±14) years old] and 10 diabetic foot patients [8 male patients, 2 female patients, aged (61±10) years old] during the operations. The samples were divided into burn wound group (9 samples), pressure ulcer group (13 samples), and diabetic foot group (10 samples). Ten slices were taken from pressure ulcer group and diabetic foot group respectively, and 5 slices in each group were used to observe the tissue morphology and expressions of Ki67 and CD31 of wounds respectively with immunofluorescence method. Ten samples from normal skin group, 9 samples from burn wound group, 13 samples from pressure ulcer group, and 10 samples from diabetic foot group were collected for analysis of mRNA expressions of vascular endothelial growth factor 192 (VEGF192), transforming growth factor β (TGF-β), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) , interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α) by real time fluorescent quantitative reverse transcription polymerase chain reaction. Data were processed with Mann-Whitney U test and Kruskal-Wallis rank-sum test. Results: (1) The expression level of Ki67 in diabetic foot group (390±100) was higher than that of pressure ulcer group (182±14, Z=-2.611, P<0.01). (2) Although there were a large number of vascular endothelial cells (CD31 positive cells) in wounds of diabetic foot group, their distribution was disordered and failed to form intact lumen. There were less vascular endothelial cells in wounds of pressure ulcer group than those of diabetic foot group, but the complete lumen was formed. (3) The mRNA expression levels of VEGF192 in wounds of burn wound group, pressure ulcer group, and diabetic foot group were significantly lower than the level in normal skin group (H=13.72, 30.50, 15.20, P<0.05 or P<0.01), and the level was the lowest in pressure ulcer group. The mRNA expression level of VEGF192 in wounds of pressure ulcer group was significantly lower than that of diabetic foot group (H=15.30, P<0.01). Compared with that of normal skin group, the mRNA expression level of TGF-β in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), while the mRNA expression levels of TGF-β in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=18.04, 14.50, P<0.01). The mRNA expression level of TGF-β in wounds of pressure ulcer group was similar to that of diabetic foot group (H=3.54, P>0.05). (4) Compared with those of normal skin group, the mRNA expression levels of VCAM-1 in wounds of burn wound group and pressure ulcer group were significantly increased (H=-22.50, -11.50, P<0.05 or P<0.01), and there was no significant difference in the mRNA expression level of VCAM-1 in wounds of diabetic foot group (H=10.00, P>0.05); the mRNA expression level of ICAM-1 in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), and the levels of ICAM-1 in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=16.50, 16.50, P<0.01). The mRNA expression level of VCAM-1 in wounds of pressure ulcer group was significantly higher than that of diabetic foot group (H=-21.50, P<0.01), the mRNA expression level of ICAM-1 in wounds of pressure ulcer group was similar to that of diabetic foot group (H=0, P>0.05). (5) Compared with those of normal skin group, except for the mRNA expression level of IL-1β in wounds of diabetic foot group showed no significant difference (H=-10.00, P>0.05), the mRNA expression levels of IL-1β in wounds of burn wound group and pressure ulcer group were significantly increased (H=-32.50, -21.50, P<0.01); the mRNA expression levels of IL-6 were significantly increased in wounds of burn wound group, pressure ulcer group, and diabetic foot group (H=-17.50, -30.50, -11.80, P<0.05 or P<0.01); except for the mRNA expression level of TNF-α in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), the mRNA expression levels of TNF-α in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=18.04, 14.50, P<0.01). The mRNA expression levels of IL-1β and TNF-α in wounds of pressure ulcer group were significantly lower than those of burn wound group (H=11.00, 27.54, P<0.05 or P<0.01), while the mRNA expression level of IL-6 was significantly higher (H=-13.00, P<0.05). The mRNA expression levels of IL-1β and TNF-α in wounds of diabetic foot group were significantly lower than those of burn wound group (H=22.50, 24.00, P<0.01), while the mRNA expression level of IL-6 showed no significant difference (H=5.70, P>0.05). Conclusions: The phenotypes of diabetic foot and pressure ulcer vary from the expressions levels of proliferating cell nuclear antigen and blood vessels forming ability to the expression levels of growth factors, cell adhesion factors, and inflammatory cytokines.

Effects of oat protein supplementation on skeletal muscle damage, inflammation and performance recovery following downhill running in untrained collegiate men

The positive influence of animal-based protein supplementation during muscle-damaging exercise has been widely studied. However, the effects of plant-based proteins remain unclear and require further clarification. This study investigated the protective role of oat protein against exercise induced muscle damage (EIMD), subsequent inflammation, and loss of performance induced by downhill running. Subjects consumed either oat protein (25 g protein) or a placebo for 14 days prior to a downhill running test and then for 4 days thereafter. Treatments with oat protein for 19 days markedly alleviated eccentric exercise induced skeletal muscle soreness, and reduced the elevation of plasma IL-6 concentrations and serum creatine kinase, myoglobin and C reactive protein contents. In addition, oat protein supplementation significantly inhibited limb edema following damaging exercise, and the adverse effects on muscle strength, knee-joint range of motion, and vertical jump performance were lessened. Furthermore, the administration of oat protein facilitated recovery from exhaustive downhill running in this study. These findings demonstrated that oat protein supplementation has the potential to alleviate the negative effects of eccentric exercise in untrained young males.

B, Broussard L, Clayton S, Currie S, Dees E, Ding X, Fellers D, Fox W, Fries E, Gonzalez F, Geltenbort P, Hickerson K, Hoffbauer M, Hoffman K, Holley A, Howard D, Ito T, Komives A, Liu C, M. M, Medina J, Morley D, Morris C, O'Connor T, Penttilä S, Ramsey J, Roberts A, Salvat D, Saunders A, Seestrom S, Sharapov E, Sjue S, Snow W, Sprow A, Vanderwerp J, Vogelaar B, P.L. W, Wang Z, Weaver H, Wexler J, Womack T, Young A, Zeck B. Status of the UCN experiment

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, τn = 877.7s (0.7s)stat (+0.4/−0.2s)sys. We discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.25 s measurement of the neutron lifetime with UCNτ.

Search for neutron dark decay: n → χ + e+e−

In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single χ along with an e+e− pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼ 4π acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n → p + e- + ν̅e decays. The summed kinetic energy (Ee+e−) from such events is reconstructed and used to set limits, as a function of the χ mass, on the branching fraction for this decay channel.

X-ray-induced reproductive dysfunction and differentially expressed piRNAs in male mice

The effects of X-ray radiation on spermatogenesis, sperm motility, and PIWI-interacting RNAs (piRNAs) in mice were analyzed. Male C57BL/6 J mice were divided into control and two irradiation groups ( n = 9 mice/group). After irradiation of their reproductive regions, the mice were fed for 3 days (irradiation group 1) or 7 days (control and irradiation group 2). The sperm viability, motility, velocity, and motion curve were analyzed. After piRNA expression profiling, quantitative reverse-transcription polymerase chain reaction was conducted for validation. Ionizing radiation led to vessel dilation and congestion, fewer spermatogenic cells, and reduced sperm production compared to the control. At 3 and 7 days postirradiation, the sperm count (grade d) increased while sperm viability and sperm lateral head displacement decreased. At 7 days, the sperm abnormality rate was higher compared to the control. Many piRNAs were differentially expressed after irradiation, including decreased and increased expression of mmu_piR_009082 and mmu_piR_020217, respectively. Downregulated piRNAs were involved in Rap1 signaling, non-homologous end-joining, hedgehog signaling, oxytocin signaling, and cholinergic synapse. Upregulated piRNAs participated in pathways including proteoglycans in cancer, phosphatidylinositol signaling, cGMP-PKG signaling, and stem cell pluripotency regulation. X-ray irradiation inhibited spermatogenesis and increased abnormal sperm rate in mice. piRNA-related signaling pathways may be involved in this process.

Epigallocatechin-3-gallate protected vanadium-induced eggshell depigmentation via P38MAPK-Nrf2/HO-1 signaling pathway in laying hens

It has been demonstrated that tea polyphenol (TP) epigallocatechin-3-gallate (EGCG) can confer protection against vanadium (V) toxicity in laying hens; however, our understanding of the molecular mechanisms beyond this effect are still limited. In this study, 360 hens were randomly assigned to the 3 groups to study whether the potential mechanism P38MAPK-Nrf2/HO-1 signaling pathway is involved in the protective effect of EGCG on eggshell pigmentation in vanadium challenged laying hens. Treatments included a control group, a 10 mg/kg V (V10), and a V10 plus 130 mg/kg of EGCG group (V10+EGCG130). Both eggshell color and protoporphyrin IX were decreased in the V10 group compared with the control diet, while EGCG130 treatment partially improved shell color and protoporphyrin IX (P < 0.05). The V10 exposure induced higher cell apoptosis rate and oxidative stress in birds as evidenced by the histological apoptosis status, decreased uterine glutathione-S transferase (GST) and high abundance of malondialdehyde (MDA) compared with the control group, whereas EGCG130 markedly alleviated oxidative stress via reducing MDA generation (P < 0.05). Dietary vanadium reduced ferrochelatase, NF-E2-related factor 2 (Nrf2), and heme oxygenase (HO-1) mRNA expression, while EGCG up-regulated Nrf2 and HO-1 expression (P < 0.05). Protein levels of Nrf2, HO-1 and phospho-p38 (P-P38) MAPK were reduced in V10 group, while dietary supplementation with 130 mg/kg EGCG markedly increased Nrf2, HO-1 and P-P38 MAPK protein levels in the uterus compared with the V10 group (P < 0.01). In conclusion, EGCG improved eggshell color and antioxidant system in V10-challenged hens, which seems to be associated with P38MAPK-Nrf2/HO-1 signaling pathway.

MRI assessment of the bone adjacent to giant cell tumours and its association with local recurrence after intralesional curettage

AIM

To assess the tumour border surrounding giant cell tumour of the bone (GCTB) using magnetic resonance imaging (MRI) and investigate its association with local recurrence.

MATERIALS AND METHODS

Sixty-nine GCTBs in proximal tibiae and distal femurs were studied. The pathological basis of the paintbrush border sign was explored. Expression of Ki-67, matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), receptor activator of nuclear factor-κ B (RANK), and RANK ligand (RANKL) in GCTBs were investigated using immunohistochemistry. Patients treated with intralesional curettage were analysed retrospectively to investigate the prognostic role of the paintbrush border sign. The differences between rates were tested using the chi-square test or Fisher's exact test, as appropriate.

RESULTS

The paintbrush border sign correlated well with infiltrative margins. The expression of MMP-9 was associated with the paintbrush border sign, and positively correlated with RANKL and VEGF expression. GCTBs with the paintbrush border sign had a higher rate of local recurrence (76.19 versus 20.59%, p<0.05). The paintbrush border sign was more common in proximal tibiae, and positively correlated with cystic change. The paintbrush border signs were detected at T1-weighted imaging, but the sign was only evident in four cases on T2-weighted imaging.

CONCLUSION

Pathologically, the paintbrush border sign correlates well with invasion of the bone around GCTB. MMP-9 might play a key role in the formation of penetrating irregular margins. The paintbrush border sign is revealed as a risk factor for local recurrence of GCTB. Sagittal T1-weighted imaging is crucial to diagnose the paintbrush border sign.

A genome-wide association study of growth and fatness traits in two pig populations with different genetic backgrounds

Improvement in growth and fatness traits are the main objectives in pig all breeding programs. Tenth rib backfat thickness (10RIBBFT) and days to 100 kg (D100), which are good predictors of carcass lean content and growth rate, respectively, are economically important traits and also main breeding target traits in pigs. To investigate the genetic mechanisms of 10RIBBFT and D100 of pigs, we sampled 1,137 and 888 pigs from 2 Yorkshire populations of American and British origin, respectively, and conducted genome-wide association study (GWAS) through combined analysis and meta-analysis, to identify SNPs associated with 10RIBBFT and D100. A total of 11 and 7 significant SNPs were identified by combined analysis for 10RIBBFT and D100, respectively. And in meta-analysis, 8 and 7 significant SNPs were identified for 10RIBBFT and D100, respectively. Among them, 6 and 5 common significant SNPs in two analysis results were, respectively, identified associated with 10RIBBFT and D100, and correspondingly explained 2.09% and 0.52% of the additive genetic variance of 10RIBBFT and D100. Further bioinformatics analysis revealed 10 genes harboring or close to these common significant SNPs, 5 for 10RIBBFT and 5 for D100. In particular, Gene Ontology analysis highlighted 6 genes, PCK1, ANGPTL3, EEF1A2, TNFAIP8L3, PITX2, and PLA2G12, as promising candidate genes relevant with backfat thickness and growth. PCK1, ANGPTL3, EEF1A2, and TNFAIP8L3 could influence backfat thickness through phospholipid transport, regulation of lipid metabolic process through the glycerophospholipid biosynthesis and metabolism pathway, the metabolism of lipids and lipoproteins pathway. PITX2 has a crucial role in skeletal muscle tissue development and animal organ morphogenesis, and PLA2G12A plays a role in the lipid catabolic and phospholipid catabolic processes, which both are involved in the body weight pathway. All these candidate genes could directly or indirectly influence fat production and growth in Yorkshire pigs. Our findings provide novel insights into the genetic basis of growth and fatness traits in pigs. The candidate genes for D100 and 10RIBBFT are worthy of further investigation.

Arabidopsis FIM4 and FIM5 regulates the growth of root hairs in an auxin-insensitive way

Tip-growing cells provide a useful model system for studying the underlying mechanisms of plant cell growth. The apical growth of root hairs is dependent on the microfilament skeleton, and auxin is an important regulator of root hair development. We functionally characterized actin bundling proteins AtFIM4 and AtFIM5, which were preferentially expressed in tip-growing cells such as pollen tubes and root hairs. The morphology and length of root hairs in atfim4/atfim5 double mutant line had obvious defects. In addition, we found the growth of root hairs of atfim4/atfim5 double mutant was insensitive to exogenous IAA (indole-3-acetic acid) treatment. So we consider that AtFIM4 and AtFIM5 act together to regulate the growth of root hair in an auxin-insensitive way.