Lipopolysaccharide reduces gonadotrophin-releasing hormone (GnRH) gene expression: role of RFamide-related peptide-3 and kisspeptin.

RFamide-related peptide (RFRP)-3 reduces luteinising hormone (LH) secretion in rodents. Stress has been shown to upregulate the expression of the RFRP gene (Rfrp) with a concomitant reduction in LH secretion, but an effect on expression of the gonadotrophin-releasing hormone (GnRH) gene (Gnrh1) has not been shown. We hypothesised that lipopolysaccharide (LPS)-induced stress affects expression of Rfrp, the gene for kisspeptin (Kiss1) and/or Gnrh1, leading to suppression of LH levels in rats. Intracerebroventricular injections of RFRP-3 (0.1, 1, 5 nmol) or i.v. LPS (15µgkg-1) reduced LH levels. Doses of 1 and 5 nmol RFRP-3 were then administered to analyse gene expression by in situ hybridisation. RFRP-3 (5 nmol) had no effect on Gnrh1 or Kiss1 expression. LPS stress reduced GnRH and Kiss1 expression, without affecting Rfrp1 expression. These data indicate that LPS stress directly or indirectly reduces Gnrh1 expression, but this is unlikely to be due to a change in Rfrp1 expression.

A long non-coding RNA regulates cadherin transcription and susceptibility to Bt toxin Cry1Ac in pink bollworm, Pectinophora gossypiella.

Extensive planting of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has spurred increasingly rapid evolution of resistance in pests. In the pink bollworm, Pectinophora gossypiella, a devastating global pest, resistance to Bt toxin Cry1Ac produced by transgenic cotton is linked with mutations in a gene (PgCad1) encoding a cadherin protein that binds Cry1Ac in the larval midgut. We previously reported a long non-coding RNA (lncRNA) in intron 20 of cadherin alleles associated with both resistance and susceptibility to Cry1Ac. Here we tested the hypothesis that reducing expression of this lncRNA decreases transcription of PgCad1 and susceptibility to Cry1Ac. Quantitative RT-PCR showed that feeding susceptible neonates small interfering RNAs (siRNAs) targeting this lncRNA but not PgCad1 decreased the abundance of transcripts of both the lncRNA and PgCad1. Moreover, neonates fed the siRNAs had lower susceptibility to Cry1Ac. The results imply that the lncRNA increases transcription of PgCad1 and susceptibility of pink bollworm to Cry1Ac. The results suggest that disruption of lncRNA expression could be a novel mechanism of pest resistance to Bt toxins.

Painful Schmorl's nodes treated by discography and discoblock.

PURPOSE: To determine the efficacy of discography and discoblock in the treatment of low back pain (LBP) associated with painful Schmorl's nodes (SNs). METHODS: Between January 2010 and February 2015, 46 patients were studied who had LBP suspected to be secondary to SNs. There were 34 men and 12 women, and mean age was 54.2 years (range 42-68 years). All patients underwent provocation discography, and discoblock was given to positive patients (confirmed to have painful SNs). Visual analogue scores (VAS) and the Oswestry Disability Index (ODI) were evaluated at 4 h and 1, 3, 6, and 12 months post-operatively. MRI was also used to evaluate the SNs at 12 months. RESULTS: Discography was performed on a total of 60 discs without infection or other complications. Positive findings were found in 71.7% discs; 20.0% were negative, and 8.3% were indeterminate. Among the positive patients who underwent discoblock, 89.2% reported an improvement in their LBP, and none reported worsening symptoms. VAS and ODI scores decreased significantly after discoblock, and there were no significant differences between 4 h and 1, 3, 6, and 12 months post-operatively. In patients with painful SNs, the vertebral body bone marrow surrounding the SN was characterized by low T1 and high T2 signals on MRI. At 12 months, the node demonstrated either high T1 and T2 signals or low T1 and T2 signals. The SNs tended to remain stable in size over time. CONCLUSIONS: Painful SNs refractory to medical or physical therapy should be an indication for treatment with discography and discoblock.

Derivation and Validation of a Clinical Prediction Scale for Isolated Distal Deep Venous Thrombosis in Patients after Acute Ischemic Stroke.

BACKGROUND: Isolated distal deep venous thrombosis (IDDVT) is a common complication after ischemic stroke. However, there is a paucity of evidence regarding the clinical features and risk factors of IDDVT in patients with acute ischemic stroke. This study aimed to establish and validate a clinical prediction scale of IDDVT at an early stage of ischemic stroke development. METHODS: We retrospectively studied consecutive patients with stroke admitted to our neurology department between January and December 2016. Selected clinical variables were assessed by multivariable logistic regression to determine the independent risk factors for IDDVT. A prediction scale was developed and verified by the receiver operating characteristic curve. RESULTS: A total of 671 patients with ischemic stroke were included in the study, with 450 patients allocated into the derivation group and 221 patients into the validation group. A substantial proportion (22.1%) of patients developed IDDVT. A 16-point prediction scale (female gender = 2, older age [≥60 years] = 3, atrial fibrillation = 2, acute infection = 2, active cancer = 5, and higher [≥2.6 mmol/L] level of low-density lipoprotein = 2) derived from a multivariable logistic regression model was highly predictive of 10-day risk of IDDVT in both the validation group (c statistic = .70, 95% confidence interval [CI], .63-0.78, P < .0001) and the derivation group (c statistic = .68, 95% CI, .63-0.74, P < .0001). CONCLUSIONS: This prediction scale may help to identify patients with ischemic stroke who are at a higher risk of developing IDDVT.

Methylation profiling of 48 candidate genes in tumor and matched normal tissues from breast cancer patients.

Gene-specific methylation alterations in breast cancer have been suggested to occur early in tumorigenesis and have the potential to be used for early detection and prevention. The continuous increase in worldwide breast cancer incidences emphasizes the urgent need for identification of methylation biomarkers for early cancer detection and patient stratification. Using microfluidic PCR-based target enrichment and next-generation bisulfite sequencing technology, we analyzed methylation status of 48 candidate genes in paired tumor and normal tissues from 180 Chinese breast cancer patients. Analysis of the sequencing results showed 37 genes differentially methylated between tumor and matched normal tissues. Breast cancer samples with different clinicopathologic characteristics demonstrated distinct profiles of gene methylation. The methylation levels were significantly different between breast cancer subtypes, with basal-like and luminal B tumors having the lowest and the highest methylation levels, respectively. Six genes (ACADL, ADAMTSL1, CAV1, NPY, PTGS2, and RUNX3) showed significant differential methylation among the 4 breast cancer subtypes and also between the ER +/ER- tumors. Using unsupervised hierarchical clustering analysis, we identified a panel of 13 hypermethylated genes as candidate biomarkers that performed a high level of efficiency for cancer prediction. These 13 genes included CST6, DBC1, EGFR, GREM1, GSTP1, IGFBP3, PDGFRB, PPM1E, SFRP1, SFRP2, SOX17, TNFRSF10D, and WRN. Our results provide evidence that well-defined DNA methylation profiles enable breast cancer prediction and patient stratification. The novel gene panel might be a valuable biomarker for early detection of breast cancer.

Correlation between biomechanical properties of the annulus fibrosus and magnetic resonance imaging (MRI) findings.

PURPOSE: To investigate the regional tensile properties of human annulus fibrosus (AF) and relate them to magnetic resonance imaging (MRI) findings. METHODS: 44 human cadaveric lumbar spines were harvested (24 male, 20 female, aged 25-64 years). MRI was used to identify Pfirrmann grade of disc degeneration, and Modic changes (MCs). Intervertebral discs were then removed and dissected into five regions: nucleus pulposus, anterior AF, anterolateral AF, lateral AF, and posterolateral AF. Samples for tensile testing (1.5 mm × 1.5 mm × 5 mm) were removed from inner, middle and outer parts of each region. RESULTS: 1969 specimens from 189 discs were stretched to failure. Average tensile stiffness (modulus) increased from 4.80 MPa in the inner AF to 13.0 MPa in the outer AF. Strength (UTS) increased similarly, from 1.18 to 3.29 MPa, whereas elongation at failure decreased, from 49 to 38%. The only significant change with age was a reduction in UTS in the middle annulus. In contrast, severe grades of disc degeneration were associated with consistent and highly significant reductions in tensile properties. Effects were greatest in the outer AF, where stiffness and strength fell by 29 and 43%, respectively. Modic changes also were associated with reduced stiffness and strength, but here the effects were greatest in the inner and middle AF. CONCLUSION: Weakening of degenerated AF may be caused by accumulating structural defects, and enzymatic degradation. MRI has the potential to identify local weakening of the AF.

Putative pathway of sex pheromone biosynthesis and degradation by expression patterns of genes identified from female pheromone gland and adult antenna of Sesamia inferens (Walker).

The general pathway of biosynthesis and degradation for Type-I sex pheromones in moths is well established, but some genes involved in this pathway remain to be characterized. The purple stem borer, Sesamia inferens, employs a pheromone blend containing components with three different terminal functional groups (Z11-16:OAc, Z11-16:OH, and Z11-16:Ald) of Type-I sex pheromones. Thus, it provides a good model to study the diversity of genes involved in pheromone biosynthesis and degradation pathways. By analyzing previously obtained transcriptomic data of the sex pheromone glands and antennae, we identified 73 novel genes that are possibly related to pheromone biosynthesis (46 genes) or degradation (27 genes). Gene expression patterns and phylogenetic analysis revealed that one desaturase (SinfDes4), one fatty acid reductase (SinfFAR2), and one fatty acid xtransport protein (SinfFATP1) genes were predominantly expressed in pheromone glands, and clustered with genes involved in pheromone synthesis in other moth species. Ten genes including five carboxylesterases (SinfCXE10, 13, 14, 18, and 20), three aldehyde oxidases (SinfAOX1, 2 and 3), and two alcohol dehydrogenases (SinfAD1 and 3) were expressed specifically or predominantly in antennae, and could be candidate genes involved in pheromone degradation. SinfAD1 and 3 are the first reported alcohol dehydrogenase genes with antennae-biased expression. Based on these results we propose a pathway involving these potential enzyme-encoding gene candidates in sex pheromone biosynthesis and degradation in S. inferens. This study provides robust background information for further elucidation of the genetic basis of sex pheromone biosynthesis and degradation, and ultimately provides potential targets to disrupt sexual communication in S. inferens for control purposes.

Double-crosslinked self-healing hydrogel alleviates osteoarthritis by protecting from wearing and targeting NF-kB signaling.

Osteoarthritis (OA) is a chronic disease that causes pain, morbidity, and disability. The main strategy for OA treatment focuses on inflammation suppression, inhibition of osteoclastogenesis, and protection of articular cartilage. These functions cannot be performed effectively by monotherapy. Therefore, an effective drug delivery system is required, capable of containing and controlling the efflux of various drugs to alleviate osteoclastogenesis, protect cartilage and subchondral bone, and suppress inflammation. In this work, an encapsulation system is constructed using a self-healing chitosan hydrogel and allocated compound drugs. The self-healing gel is composed of branched-functionalized chitosan, created by simultaneously using polycaprolactone polyethylene glycol azide as a block polymer and the host-guest assembly of ß-cyclodextrin and adamantane. Inhibitors of the NFkB pathway are loaded into the cavities of ß-cyclodextrin and the spring-like structure of the block polymer, which can be rapidly released upon joint friction (due to the reassembly of ß-cyclodextrin and adamantane by shear stress and the stretch of the block polymer). In vitro experiments using BMMs and the ATDC5 cell line confirm that the developed hydrogel can simultaneously suppress osteoclastogenesis and induce chondrogenesis. Additionally, a model of knee arthritis in C57 mice was used to confirm that this double-crosslinked encapsulation system can lubricate the knee joint surface and provide adequate protection on demand through shear-responsive drug release.

Oncoplastic breast-conserving surgery improves cosmetic outcomes without increasing recurrence risk compared to modified radical mastectomy in early breast cancer patients: development and validation of a recurrence risk prediction model.

In the quest for effective treatment of early-stage breast cancer, this study aimed to compare the clinical efficacy of modified radical mastectomy (MRM) and oncoplastic breast-conserving surgery (OBCS). Breast cancer remains a major health concern globally, where early detection and effective treatment strategies are crucial for improving the outcomes of patients. MRM and OBCS are two primary treatment modalities for breast cancer, each with its distinct benefits and challenges. Through a retrospective analysis, we found that although the patients in the OBCS group experienced a longer operation time, they had significantly less intraoperative bleeding, postoperative drainage, and hospitalization time compared to the MRM group. Furthermore, patients in the OBCS group demonstrated higher subjective satisfaction and quality of life scores, along with better objective outcomes. In terms of postoperative complications and recurrence rates, no significant difference was identified between the two groups. However, our multivariate Cox regression analysis identified lymph node metastasis and molecular type as independent prognostic factors for disease-free survival (DFS). Subsequently, we constructed a risk model based on these variables, which was proven to be effective in predicting recurrence, with an area under the risk score curve for recurrence prediction being 0.852. The group with a lower risk score demonstrated a significantly higher DFS rate. Our study suggests that compared with MRM, OBCS can significantly reduce surgical incision, improve patient satisfaction, and does not increase the risk of complications or recurrence. Our risk model, developed using Cox regression, also demonstrated high clinical value in predicting breast cancer recurrence, thereby aiding in personalized patient management and treatment planning.

Evaluation of indocyanine green combined with methylene blue staining in sentinel lymph node biopsy of breast cancer.

Background: Methylene blue as tracer used in sentinel lymph node biopsy (SLNB) have low detection rate and high false negative rate. Indocyanine green (ICG) can detect the flow of subcutaneous lymphatic vessels and the position of lymph nodes dynamically. This study sought to evaluate the efficacy of ICG combined with methylene blue staining in SLNB of breast cancer. Methods: One hundred and fifty-six early breast cancer patients treated at our hospital from July 2020 to May 2022 were enrolled in this study. SLNB was performed by ICG combined with methylene blue staining under the guidance of the fluorescent tracer navigation system FLI-10B. Standard axillary lymph node dissection (ALND) was performed in patients with sentinel lymph node (SLN) metastasis confirmed by intraoperative frozen pathology, while low ALND was performed in patients with negative SLNs. According to the staining condition, the SLNs were divided into: (I) the combined group (SLNs with methylene blue staining and/or ICG luminescence); (II) the methylene blue group (SLNs with methylene blue staining alone); and (III) the ICG group (SLNs with ICG luminescence alone). The detection rate, accuracy, sensitivity, and false negative rate of SLNB were compared among the 3 groups. Results: A total of 592 SLNs were detected in the combined group (average 3.8 SLNs), yielding a detection rate of 97.4%; the accuracy, sensitivity, and false negative rates were 97.4%, 92.7%, and 7.3%. In the methylene blue group, 390 SLNs were detected (average 2.5 SLNs), yielding a detection rate of 84.6%; the accuracy, sensitivity, and false negative rates were 83.3%, 89.1%, and 10.9%. A total of 483 SLNs were detected in the ICG group (average 3.1 SLNs), the detection rate was 92.9%; the accuracy, sensitivity and false negative rates were 91.7%, 90.9%, and 9.1%. The average number of detected SLNs, detection rate and accuracy rate in the combined group were higher than those in the methylene blue group (P<0.05), and the accuracy rate of the combined group was higher than that of the ICG group (P<0.05). Conclusions: ICG combined with methylene blue staining is a promising and effective tracing strategy in the SLNB of breast cancer with high detection and accuracy rates.

Identification of Wild-Type CYP321A2 and Comparison of Allelochemical-Induced Expression Profiles of CYP321A2 with Its Paralog CYP321A1 in Helicoverpa zea.

One possible way to overcome the diversity of toxic plant allelochemicals idiosyncratically distributed among potential host plants is to have more counterdefense genes via gene duplication or fewer gene losses. Cytochrome P450 is the most important gene family responsible for detoxification of the diversity of plant allelochemicals. We have recently reported the identification and cloning of the transposon (HzSINE1)-disrupted non-functional CYP321A2, a duplicated paralog of the xenobiotic-metabolizing P450 CYP321A1 from a laboratory colony of Helicoverpa zea. Here we report the identification of the wild-type intact allele of CYP321A2 from another H. zea colony. This CYP321A2 allele encodes a deduced protein of 498 amino acids and has the P450 signature motifs. Quantitative RT-PCR experiments showed that this CYP321A2 allele was highly expressed in midgut and fat body and achieved the highest expression level in the developmental stage of 5th and 3rd instar larvae. CYP321A2 and CYP321A1 were constitutively expressed in low levels but can be differentially and significantly induced by a range of the plant allelochemicals and plant signal molecules, among which xanthotoxin, flavone, and coumarin were the most prominent inducers of CYP321A2 both in midgut and fat body, whereas flavone, coumarin, and indole-3-carbinol were the prominent inducers of CYP321A1 in midgut and fat body. Moreover, xanthotoxin- and flavone-responsive regulatory elements of CYP321A1 were also detected in the promoter region of CYP321A2. Our results enrich the P450 inventory by identifying an allelochemical broadly induced CYP321A2, a paralog of CYP321A1 in H. zea. Our data also suggest that the CYP321A2/CYP321A1 paralogs are a pair of duplicated genes of multigene families and CYP321A2 could potentially be involved in the detoxification of plant allelochemicals and adaptation of H. zea to its chemical environment.

[Short-segment pedicle screw fixation combined with vertebroplasty for the treatment of Kümmell disease with kyphosis].

OBJECTIVE: To explore the clinical effects of posterior short-segment pedicle screw internal fixation combined with vertebroplasty for the treatment of Kümmell disease with kyphosis. METHODS: Twenty-four patients with Kümmell disease complicated with kyphosis treated by posterior short-segment pedicle screw internal fixation combined with vertebroplasty from January 2016 to December 2018 were retrospectively analyzed, including 6 males and 18 females, aged 63 to 85 (73.1±6.5) years old. The clinical effect was evaluate by visual analogue scale (VAS), Oswestry Disability Index (ODI), the anterior height of injured vertebral body, and the sagittal Cobb angle of the affected segment beforeoperation, at 3 days and final follow up after operation. And the surgical complications were observed. RESULTS: All 24 patients were followed up from 12 to 24 months with an average of (15.5±3.2) months. The VAS score was decreased from 5.21±1.06 preoperatively to 2.38±0.58 at 3 days postoperatively and 1.71±0.75 at final follow-up;ODI was decreased from (50.4±13.5)% preoperatively to (20.9±8.0)% at 3 days postoperatively and (16.7±9.6)% at final follow-up;the anterior height of injured vertebral body was restored from (8.0±4.2) mm before surgery to (18.1±5.0) mm at 3 days after surgery and (16.8±5.1) mm at final follow up;the sagittal Cobb angle of affected segment was decreased from (19.5±6.3)° preoperatively to (7.6±2.1)° at 3 days after surgery and(8.4±1.7)° at final follow-up. VAS, ODI, anterior height of injured vertebral body, and sagittal Cobb angle of affected segment were significantly improved at 3 days after operation and at final follow-up (P<0.05). Two patients had complications, including asymptomaticcement leakage in 1 patient and superficial wound infection in 1 patient. CONCLUSION: Posterior short-segment pedicle screw internal fixation combined with vertebroplasty for the treatment of Kümmell disease with kyphosis has relatively small surgical trauma, excellent clinical results, good vertebral height recovery, satisfactory correction of kyphotic angle, and fewer complications, etc. It is a safe and effective surgical method to treat Kümmell disease with kyphosis.

Migraine-induced stroke with risk factors--involving two cerebral artery territories.

A patient with migraine-induced stroke with risk factors involving both anterior cerebral artery and posterior cerebral artery territory was presented. To better explain the symptom, the mechanisms of the migraine-induced stroke with risk factors were assessed and a hypothesis was raised.

The role of the programmed cell death protein-1/programmed death-ligand 1 pathway, regulatory T cells and T helper 17 cells in tumor immunity: a narrative review.

Tumor immunotherapy, especially that involving programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) immunosuppressive checkpoint inhibitors, has become an important part of tumor treatment strategy in the past decade. Blocking PD-1/PD-L1 signaling pathway can reduce the inhibitory effect of PD-1 pathway on T cells, promote the anti-tumor activity of activated T cells, and prolong the remission period of tumor. While PD-1/PD-L1 immunotherapy is effective in the treatment of solid malignant tumors, it also has shortcomings, due to the complexity of the tumor microenvironment (TME). Regulatory T cells (Tregs) and T helper 17 (Th17) cells play an important role in the TME and are closely related to the occurrence and development of tumors. Tregs can inhibit the anti-tumor immune effect, while Th17 cells play a dual role in tumor immunity, which not only promotes tumorigenesis but also promotes anti-tumor immunity. In the occurrence and development of tumor, PD-1/PD-L1 pathway, Tregs and Th17 cells are interrelated. However, the complicated relationship between the PD-1/PD-L1 pathway, Tregs, and Th17 cells has not been fully clarified. Here, we summarize the immunoregulation mechanisms and discuss the crosstalk between the PD-1/PD-L1 pathway, Tregs, and Th17 cells, with the aim of providing novel insights for future cancer treatment.

Percutaneous kyphoplasty: Risk Factors for Recollapse of Cemented Vertebrae.

INTRODUCTION: Percutaneous kyphoplasty can offer pain relief and restoration of vertebral height immediately after the procedure; however, little is known about how many vertebrae recollapse during follow-up or why recollapse occurs. In the present study, we define recollapse of a treated vertebra, assess how common it is following percutaneous kyphoplasty, and investigate risk factors for the condition. METHODS: In total, 203 consecutive patients who underwent percutaneous kyphoplasty were reviewed after an average 12.7 months to assess what proportion of cement-augmented vertebrae had recollapsed. Potential risk factors for recollapse included age, gender, body weight, body height, body mass index, treated level, duration of symptoms, follow-up duration, preoperative T-scores, surgical approach, the intravertebral cleft, contact of polymethyl methacrylate (PMMA) with endplates, cement volume, cement leakage, and midline vertebral body height. Stepwise multivariate linear regression was conducted to predict recollapse as quantified by midline vertebral height loss. RESULTS: Overall, 38.9% of the augmented vertebrae recollapsed. In the recollapse group, the average midline vertebral height ratio and kyphotic angles statistically significantly changed during follow-up (P < 0.05). Pain scores decreased immediately after percutaneous kyphoplasty and generally remained low at follow-up. Significant predictors of midline vertebral height loss at follow-up included presence of an intravertebral cleft, postoperative vertebral height, and non-PMMA-endplate-contact. Together, these factors accounted for 28% of the variability in midline height loss. CONCLUSIONS: Benefits of percutaneous kyphoplasty are partly offset by subsequent recollapse. Recollapse is greater if there is an intravertebral cleft, non-PMMA-endplate-contact and an increase in the post vertebral height.

Obesity Mediates Apoptosis and Extracellular Matrix Metabolic Imbalances via MAPK Pathway Activation in Intervertebral Disk Degeneration.

Obesity may promote intervertebral disc degeneration (IDD) by non-mechanical means, by influencing levels of free fatty acids which could impair cell metabolism. This study aims to establish metabolic factors in obesity-related IDD independent of mechanical loading. In clinical study, we retrospectively reviewed 128 volunteers (73 males, 55 females, aged 29-88 years) and compared their grades of disk degeneration with obesity-related factors such as body weight, BMI, and serum lipid levels. Clinically, the IDD group showed increased age, BMI and serum triglyceride. Triglyceride was a significant risk factor for IDD even after correction for BMI and age (P = 0.007). In obesity animal model, rats were fed a high-fat diet (HFD) in order to study its effects on disk metabolism and apoptosis. HFD rats had significantly higher serum levels of lipids, including triglyceride and non-esterified fatty acid, and showed significantly decreased markers of anabolism, increased catabolism and apoptosis in disk. Finally, rat nucleus pulposus (NP) cells were stimulated in vitro with a fatty acid (palmitic acid, PA) to gauge its effects on cell metabolism and apoptosis. Cell culture studies showed that NP cells exposed to PA showed increased apoptosis for activation of caspase 3, 7, 9, and PARP, which was primarily via the MAPK signal pathway, especially ERK pathway. In conclusion, hypertriglyceridemia can lead to IDD, independently of age and BMI. Hypertriglyceridemia appears to mediate disk cell apoptosis and matrix catabolism primarily via the ERK pathway.

Role of the posterodorsal medial amygdala in predator odour stress-induced puberty delay in female rats.

Puberty onset is influenced by various factors, including psychosocial stress. The present study investigated cat-odour stress on puberty onset and oestrous cyclicity in rats. Female weanling rats were exposed to either soiled cat litter or fresh unused litter for 10 consecutive days. Following vaginal opening (VO), rats were smeared for 14 days to determine oestrous cyclicity. Anxiety-like behaviour was assessed using standard anxiety tests. Brains were collected to determine corticotrophin-releasing factor (CRF), CRF receptor 1 (CRF-R1) and CRF receptor 2 (CRF-R2) mRNA in the paraventricular nucleus (PVN), as well as the central nucleus of the amygdala (CEA) and the medial nucleus of the amygdala (MEA). Cat odour delayed VO and first oestrus, disrupted oestrous cycles and caused anxiogenic responses. Cat odour elicited increased CRF mRNA expression in the PVN but not in the CeA. CRF-R1 and CRF-R2 mRNA levels in the PVN and CeA were unaffected by cat odour; however, CRF-R1 mRNA levels were decreased in the MeA. The role of CRF signalling in the MeA, particularly its posterodorsal subnucleus (MePD), with respect to pubertal timing was directly examined by unilateral intra-MePD administration of CRF (0.2 nmol day-1 for 14 days) via an osmotic mini-pump from postnatal day 24 and was shown to delay VO and first oestrus. These data suggest that CRF signalling in the MePD may be associated with predator odour-induced puberty delay.

The mechanism of thoracolumbar burst fracture may be related to the basivertebral foramen.

BACKGROUND CONTEXT: The basivertebral foramen (BF), located in the middle posterior wall of the vertebral body, may induce local weakness and contribute to the formation of a retropulsed bone fragment (RBF) in thoracolumbar burst fracture (TLBF). We hypothesize that the mechanism of TLBF is related to the BF. PURPOSE: This study aimed to clarify the relationship between RBFs and the BF in TLBFs, and to explain the results using biomechanical experiments and micro-computed tomography (micro-CT). STUDY DESIGN: A comprehensive research involving clinical radiology, micro-CT, and biomechanical experiments on cadaveric spines was carried out. PATIENT SAMPLE: A total of 162 consecutive patients diagnosed with TLBF with RBFs, drawn from 256 patients who had reported accidents or injuries to their thoracolumbar spine, comprised the patient sample. OUTCOME MEASURES: Dimensions and location of the RBFs in relation to the BF were the outcome measures. MATERIALS AND METHODS: Computed tomography reconstruction imaging was used to measure the dimensions and location of RBFs in 162 patients (length, height, width of RBF and vertebral body). Furthermore, micro-CT scans were obtained of 10 cadaveric spines. Each vertebral body was divided into three layers (superior, middle, and inferior), and each layer was divided further into nine regions (R1-R9). Microarchitecture parameters were calculated from micro-CT scans, including bone volume fraction (BV/TV), connectivity (Conn.D), trabecular number (Tb.N), trabecular thickness (Tb.Th), and bone mineral density (BMD). Differences were analyzed between regions and layers. Burst fractures were simulated on cadaveric spines to explore the fracture line location and test the relationship between RBFs and BF. RESULTS: Retropulsed bone fragment width was usually one-third of the width of the vertebral body, whereas RBF length and height were approximately half of the corresponding vertebral body dimensions. Measures of trabecular bone quality were generally lowest in those central and superior regions of the vertebral body which are adjacent to the BF and which are most affected by burst fracture. In simulated TLBFs, the fracture line went across the vertex or upper surface of the BF. CONCLUSIONS: The most vulnerable regions in the vertebral body lie within or just superior to the BF. The central MR2 region in particular is at risk of fracture and RBF formation.

Mechanism of formation of intravertebral clefts in osteoporotic vertebral compression fractures: An in vitro biomechanical study.

BACKGROUND CONTEXT: Intravertebral clefts (IVCs) are vacuum-like cavities commonly associated with osteoporotic vertebral compression fractures (OVCFs). IVCs promote cement leakage during kyphoplasty, suggesting a physical link with the basivertebral foramen, although this is uncertain. PURPOSE: The present study aims to create IVCs in mechanical experiments on cadaveric spines in order to clarify their pathogenesis, structure, and links with the basivertebral foramen. STUDY DESIGN AND METHODS: In total, 15 three-vertebra lumbar specimens from five cadavers aged 68 to 71 years were subjected to axial compressive overload followed by cyclic loading in flexion and extension to create an OVCF together with an IVC. Computed tomography scans and radiographs were used to confirm structural changes and micro-CT was used to measure trabecular bone properties in five specimens. Unipedicular vertebroplasty was then performed on 10 damaged specimens until fluoroscopy revealed extravasation of cement. RESULTS: In every specimen, loading created an OVCF with an IVC. Dissection and imaging showed that the IVC was always connected with the basivertebral foramen. The central vertebral region, including the IVC, had the lowest connectivity density, trabecular number, and bone volume fraction, and the highest trabecular separation. Vertebroplasty caused cement leakage through the basivertebral foramen in nine specimens and into an adjacent disc in one specimen. CONCLUSION: Cyclic loading in flexion and extension applied to a fractured osteoporotic vertebra can create an IVC, which then allows cement leakage via the basivertebral foramen.

Superior cortical screw in osteoporotic lumbar vertebrae: A biomechanics and microstructure-based study.

BACKGROUND: Osteoporosis reduces the bone-screw purchase, potentially reducing pullout strength and other biomechanical properties. However, the existing pedicle screw approach may not compensate for the detrimental effects of decreased vertebral bone mineral density. METHODS: Two methods of screw insertion were performed in thirteen cadaveric osteoporotic lumbar vertebrae: Magerl's method in the left pedicle, and superior cortical screw method in the right (its entry point located vertically 3 mm above Magerl's point). Before screw fixations, the pedicle and its corresponding vertebral body were divided into six equal layers from cranial to caudal by performing micro-CT and tested for microstructure properties, such as bone mineral density, trabecular bone volume fraction, trabecular thickness, trabecular separation and trabecular number. Further, pedicle was horizontally divided into three regions and tested. After screw fixations, microstructure properties of the bone surrounding the screws were analyzed. Finally, the screw pullout strength was tested biomechanically. FINDINGS: The bone structure is denser in the upper third of the pedicle and its corresponding vertebral body. A similar microstructure is seen within the pedicle. This study reveals that the pullout strength is significantly correlated to the bone mineral density, trabecular bone volume fraction and trabecular thickness. Biomechanical test showed pullout strength in the superior cortical screw group with mean 613.3 N (SD 200.4) was 22.4% higher than that in the Magerl group with mean 501.2 N (SD 256.6). INTERPRETATION: The superior cortical screw method can be a reliable alternative, to provide better pullout strength for posterior lumbar instrumentation, especially in osteoporotic patients.