Maisonneuve fracture treated with short leg cast: A case report with 41-month follow-up.

RATIONALE: Maisonneuve fracture is a specific type of severe ankle injury. To our current knowledge, once a Maisonneuve fracture is diagnosed, the surgery is always recommended for fear of sequelae from inaccurate joint reconstruction. However, in this case, we treated a Maisonneuve fracture with a short leg cast, and the 41-month follow-up showed a favorable outcome with no post-traumatic osteoarthritis, chronic pain, and instability. Therefore, this case provides evidence for the feasibility of conservative treatment of Maisonneuve fracture. PATIENT CONCERNS: A female patient in her early twenties sprained her left ankle while running, suffering regional pain, swelling, and limited mobility. DIAGNOSES: We diagnosed a Maisonneuve fracture with superior fibular fracture and Volkmann tuberosity fracture, a slight separation of inferior tibiofibular syndesmosis (ITS). INTERVENTIONS: The patient rejected our surgical recommendations in favor of nonsurgical treatment, in addition to refusing immobilization of the knee. Consequently, we had to treat her with a short leg cast for 8 weeks and asked her to return for regular follow-up visits. OUTCOMES: At the final follow-up, the radiography showed complete healing of proximal fibula fracture. The patient reported no discernible subjective differences between her bilateral ankles. The range of motion of the left ankle was measured at 22° of dorsiflexion and 40° of plantarflexion. Functional assessments using Olerud-Molander ankle scale and American Orthopedic Foot and Ankle Society Ankle-Hindfoot scale both scored 100 points. Additionally, the radiographic assessment classified arthritis as stage 0 according to Morrey-Wiedeman classification. LESSONS: To avoid missing and misdiagnosing, the physical examination should always extend to 2 neighboring joints. Secondly, if a Maisonneuve fracture is suspected, further computed tomography scans, radiography, and magnetic resonance imaging can help to determine the stability of the ITS and the integrity of the lateral collateral ligaments before making therapeutic decisions. Finally, considering the lateral collateral ligaments may remain intact, we recommend stabilizing ITS by repairing the medial ligaments, which can be conducted arthroscopically and be more minimally invasive, providing an elastic fixation that aligns better with the biomechanics of the ITS which is characterized as a micro-mobile rather than fully fixed joint.

Dosimetric comparison of HyperArc and InCise MLC-based CyberKnife plans in treating single and multiple brain metastases.

BACKGROUND AND PURPOSE: This study aimed to compare the dosimetric attributes of two multi-leaf collimator based techniques, HyperArc and Incise CyberKnife, in the treatment of brain metastases. MATERIAL AND METHODS: 17 cases of brain metastases were selected including 6 patients of single lesion and 11 patients of multiple lesions. Treatment plans of HyperArc and CyberKnife were designed in Eclipse 15.5 and Precision 1.0, respectively, and transferred to Velocity 3.2 for comparison. RESULTS: HyperArc plans provided superior Conformity Index (0.91 ± 0.06 vs. 0.77 ± 0.07, p < 0.01) with reduced dose distribution in organs at risk (Dmax, p < 0.05) and lower normal tissue exposure (V4Gy-V20Gy, p < 0.05) in contrast to CyberKnife plans, although the Gradient Indexes were similar. CyberKnife plans showed higher Homogeneity Index (1.54 ± 0.17 vs. 1.39 ± 0.09, p < 0.05) and increased D2% and D50% in the target (p < 0.05). Additionally, HyperArc plans had significantly fewer Monitor Units (MUs) and beam-on time (p < 0.01). CONCLUSION: HyperArc plans demonstrated superior performance compared with MLC-based CyberKnife plans in terms of conformity and the sparing of critical organs and normal tissues, although no significant difference in GI outcomes was noted. Conversely, CyberKnife plans achieved a higher target dose and HI. The study suggests that HyperArc is more efficient and particularly suitable for treating larger lesions in brain metastases.

Management and classification of the fracture of lateral process of talus: An overview and literature update.

Fracture of the lateral process of the talus (FLPT) is uncommon in clinical practice and can be easily missed or misdiagnosed. In recent years, as researchers from all over the world have further deepened their research on FLPT, there has been a breakthrough in the classification, and the methods and principles of clinical management have changed accordingly; however, there is still no standardized guideline for the diagnosis and management of FLPT, and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years. In this article, we review the clinical classification, classification-based therapeutic recommendations, and prognosis of FLPT, with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

Revealing the Antiperspirant Components of Floating Wheat and Their Mechanisms of Action through Metabolomics and Network Pharmacology.

Floating wheat is a classical herbal with potential efficacy in the treatment of hyperhidrosis. Aiming at revealing the main components and potential mechanisms of floating wheat, a comprehensive and unique phytopharmacology profile study was carried out. First, common wheat was used as a control to look for chemical markers of floating wheat. In the screening analysis, a total of 180 shared compounds were characterized in common wheat and floating wheat, respectively. The results showed that floating wheat and common wheat contain similar types of compounds. In addition, in non-targeted metabolomic analysis, when taking the contents of the constituents into account, it was found that there indeed existed quite a difference between floating wheat and common wheat and 17 potential biomarkers for floating wheat. Meanwhile, a total of seven components targeted for hyperhidrosis were screened out based on network pharmacology. Seven key differential components were screened, among which kaempferol, asiatic acid, sclareol, enoxolone, and secoisolariciresinol had higher degree values than the others. The analysis of interacting genes revealed three key genes, namely, MAP2K1, ESR1, and ESR2. The Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses showed that various signaling pathways were involved. Prolactin signaling, thyroid cancer, endocrine resistance, gonadotropin secretion, and estrogen signaling pathways were the main pathways of the intervention of floating wheat in excessive sweating, which was associated with the estrogenic response, hormone receptor binding, androgen metabolism, apoptosis, cancer, and many other biological processes. Molecular docking showed that the screened key components could form good bindings with the target proteins through intermolecular forces. This study reveals the active ingredients and potential molecular mechanism of floating wheat in the treatment of hyperhidrosis and provides a reference for subsequent basic research.

Evaluation of Interfraction Setup Uncertainty of Patients With Glioblastoma Wearing TTFields (Tumor Treating Fields) During Radiation Therapy.

PURPOSE: Tumor treating fields (TTFields) with concurrent radiation therapy (RT) might improve the outcome of patients with newly diagnosed glioblastoma. Several trials, including that conducted in our center, have allowed patients to wear TTFields during RT. We aimed to evaluate the setup uncertainty introduced by TTFields and calculate the planning target volume (PTV) margin for clinical reference. METHODS AND MATERIALS: We collected and analyzed 201 cone beam computed tomography images of 22 patients in our center. Patients with or without TTFields were divided into the control and TTFields groups. We evaluated the setup errors in 6 degrees of freedom and 3 degrees of freedom and the magnitudes in the 3-dimensional vectors. An estimated PTV margin for patients requiring nonimaging-guided RT was recommended. RESULTS: A significant difference was observed in the longitudinal axis between the TTFields and control groups (P < .05). These results were consistent with that of the intragroup comparison of the TTFields group. The position error of the longitudinal axis (from head to feet) was -0.51 ± 2.05 mm in the TTFields group. CONCLUSIONS: Wearing TTFields during RT increased the uncertainty, especially in the longitudinal axis, with a system error of 1.40 mm and a random error of 1.28 mm. Daily image guided RT for TTFields patients seems necessary. However, the recommended expansion margin of the PTV is 5 mm for patients requiring nonimage-guided RT to enhance the safety and efficacy of treatment.

Dosimetric quality of HyperArc in boost radiotherapy for single glioblastoma: comparison with CyberKnife and manual VMAT.

BACKGROUND: Stereotactic radiotherapy (SRT) and hypo-fractionated radiotherapy are feasible treatment options for single glioblastoma multiforme when combined with conventional radiotherapy or delivered alone. HyperArc (HA), a novel linac-based method with 4 noncoplanar arcs, has been introduced into stereotactic radiosurgery (SRS) for single and multiple metastases. In this study, we compared the dosimetric quality of HyperArc with the well-established CyberKnife (CK) and conventional VMAT methods of SRT for a single, large target. METHODS: Sixteen patients treated in our center with their clinical CK plans were enrolled, and the linac-based plans were designed in silico. From the aspect of normal tissue protection and treatment efficacy, we compared the conformity index (CI), gradient index (GI), homogeneity index (HI), dose distribution in planning target volume, dose in the normal brain tissue, and mean dose of several organs at risk (OARs). All of the data were evaluated with nonparametric Kruskal‒Wallis tests. We further investigated the relationship of the dose distribution with the tumor volume and its location. RESULTS: The results showed that with a higher CI (0.94 ± 0.03) and lower GI (2.57 ± 0.53), the HA plans generated a lower dose to the OARs and the normal tissue. Meanwhile, the CK plans achieved a higher HI (0.35 ± 0.10) and generated a higher dose inside the tumor. Although manual VMAT showed slight improvement in dose quality and less monitoring units (2083 ± 225), HA can save half of the delivery time of CK (37 minutes) on average. CONCLUSION: HA plans have higher conformity and spare OARs with lower normal tissue irradiation, while CK plans achieve a higher mean dose in tumors. HA with 4 arcs is sufficient in dosimetric quality for a single tumor with great convenience in planning and treatment processes compared with conventional VMAT. The tumor size and location are factors to be considered when selecting treatment equipment.

The leucine-responsive regulatory protein SCAB_Lrp modulates thaxtomin biosynthesis, pathogenicity, and morphological development in Streptomyces scabies.

Streptomyces scabies is the best-characterized plant-pathogenic streptomycete, which is a special species among the large genus Streptomyces. The pathogenicity of S. scabies relies on the production of the secondary metabolite thaxtomin A. Little is known about the molecular mechanisms underlying the regulation of thaxtomin biosynthesis in S. scabies beyond the pathway-specific activator TxtR and the cellulose utilization repressor CebR. The leucine-responsive regulatory protein (Lrp) family modulates secondary metabolism in nonpathogenic streptomycetes. However, the regulatory relationship between the Lrp and pathogenic streptomycetes remains unknown. In this study, we demonstrated that SCAB_Lrp (SCAB_77931) from S. scabies significantly affects thaxtomin biosynthesis, pathogenicity, and morphological development. SCAB_Lrp deletion resulted in a dramatic decline in thaxtomin A production and a low-virulence phenotype of S. scabies. An in-depth dissection of the regulatory mechanism of SCAB_Lrp revealed that it positively regulates the transcription of the thaxtomin biosynthetic gene cluster by directly binding to the promoter of the cluster-situated regulator gene txtR. SCAB_Lrp also controls the morphological development of S. scabies by directly activating the transcription of amfC, whiB, and ssgB. SCAB_Lrp directly controls the transcription of its own gene by binding a specific sequence (5'-GGACAGTCGCCGTGCTACG-3'). Moreover, phenylalanine and methionine have been characterized as SCAB_Lrp effectors by strengthening the binding affinity and complex status between SCAB_Lrp and DNA. Our findings characterize a multifunctional regulatory protein, SCAB_Lrp, that controls secondary metabolism, pathogenicity, and sporulation in S. scabies and provide new insights into the complex regulatory network that modulates thaxtomin phytotoxins in pathogenic Streptomyces.

Joint engineering of SACE_Lrp and its target MarR enhances the biosynthesis and export of erythromycin in Saccharopolyspora erythraea.

The Lrp and MarR families are two groups of transcriptional regulators widely distributed among prokaryotes. However, the hierarchical-regulatory relationship between the Lrp family and the MarR family remains unknown. Our previous study found that an Lrp (SACE_Lrp) from Saccharopolyspora erythraea indirectly repressed the biosynthesis of erythromycin. In this study, we characterized a novel MarR family protein (SACE_6745) from S. erythraea, which is controlled by SACE_Lrp and plays a direct regulatory role in erythromycin biosynthesis and export. SACE_Lrp directly regulated the expression of marR by specifically binding a precise site OM (5'-CTCCGGGAACCATT-3'). Gene disruption of marR increased the production of erythromycin by 45% in S. erythraea A226. We found that MarR has direct DNA-binding activity for the promoter regions of the erythromycin biosynthetic genes, as well as an ABC exporter SACE_2701-2702 which was genetically proved to be responsible for erythromycin efflux. Disruption of SACE_Lrp in industrial S. erythraea WB was an efficient strategy to enhance erythromycin production. Herein, we jointly engineered SACE_Lrp and its target MarR by deleting marR in WBΔSACE_Lrp, resulting in 20% increase in erythromycin yield in mutant WBΔLrpΔmarR compared to WBΔSACE_Lrp, and 39% to WB. Overall, our findings provide new insights into the hierarchical-regulatory relationship of Lrp and MarR proteins and new avenues for coordinating antibiotic biosynthesis and export by joint engineering regulators in actinomycetes. KEY POINTS: • The hierarchical-regulatory relationship between SACE_Lrp and MarR was identified. • MarR directly controlled the expression of erythromycin biosynthesis and export genes. • Joint engineering of SACE_Lrp-MarR regulatory element enhanced erythromycin production.

[Application value of procalcitonin clearance rate on clinical outcome in patients with severe pneumonia].

OBJECTIVE: To investigate the changes in serum procalcitonin (PCT) in patients with severe pneumonia, and to analyze its value on evaluating the clinical outcome of patients with severe pneumonia. METHODS: A total of 58 patients with severe pneumonia aged over 18 years, and admitted to intensive care unit (ICU) of Zhuozhou City Hospital of Hebei Province from January 2017 to July 2018 were enrolled. The patients were divided into recovery group (the symptoms and signs of pneumonia disappeared or improved, and the X-ray chest films improved or did not make significant progress) and deterioration group (the symptoms and signs of pneumonia persisted or progressed, while X-ray chest radiography progressed, as well as serious complications such as involvement of other organ functions due to deterioration of pulmonary infection or septic shock) according to the therapeutic outcome. The serum PCT levels at 1, 3, 5, 7, 9 days after severe pneumonia diagnosed were recorded, and procalcitonin clearance rate (PCTc) was calculated. The acute physiology and chronic health evaluation II (APACHE II) score was estimated within 24 hours when severe pneumonia was diagnosed. Receiver operating characteristic (ROC) curve was drawn, and the area under ROC curve (AUC) was calculated to analyze the value of PCTc on evaluating the clinical outcome of patients with severe pneumonia. RESULTS: Among 58 patients, 33 (56.9%) had better outcome after active treatment (recovery group), and 25 (44.1%) had worse condition (deterioration group). There was no significant difference in PCT level at 1 day or 3 days between the recovery group and the deterioration group [µg/L: 5.05 (3.89, 7.61) vs. 5.29 (4.15, 7.46) at 1 day, 4.59 (4.02, 6.90) vs. 5.70 (4.59, 7.28) at 3 days, both P > 0.05]. With the prolongation of treatment time, serum PCT level was gradually decreased in the recovery group, while remained at higher level in the deterioration group, which was significantly lowered at 5, 7, 9 days in the recovery group as compared with that in the deterioration group [µg/L: 2.92 (2.09, 3.42) vs. 6.09 (3.24, 7.96) at 5 days, 1.94 (1.50, 2.07) vs. 7.65 (5.60, 10.52) at 7 days, 1.37 (0.91, 1.74) vs. 8.96 (6.09, 10.87) at 9 days, all P < 0.01]. PCTc at 3, 5, 7, 9 days in the recovery group were significantly higher than those in the deterioration group [15.10 (-17.80, 32.10)% vs. -1.53 (-20.80, 11.48)% at 3 days, 47.50 (30.25, 60.34)% vs. 6.25 (-14.58, 29.05)% at 5 days, 76.44 (53.18, 77.92)% vs. -11.20 (-66.75, -1.38)% at 7 days, 80.01 (59.86, 88.27)% vs. -38.15 (-99.38, -2.81)% at 9 days, all P < 0.05]. ROC curve analysis showed that PCTc at 3, 5, 7 and 9 days were valuable for evaluating the clinical outcome of patients with severe pneumonia, and 9-day PCTc had the greatest value, the AUC was 0.978 [95% confidence interval (95%CI) = 0.945-1.000, P = 0.000], which was higher than APACHE II (AUC = 0.442, 95%CI = 0.280-0.610, P = 0.392); when the best cut-off value of 9-day PCTc was 93.00%, its sensitivity was 99.0%, and specificity was 87.3%. CONCLUSIONS: The PCT level of patients with severe pneumonia remained at a high level, which was related with the deterioration of the disease. PCTc, as an index to evaluate the clinical outcome of patients with severe pneumonia, has good application value.

Discovery of novel propargylamine-modified 4-aminoalkyl imidazole substituted pyrimidinylthiourea derivatives as multifunctional agents for the treatment of Alzheimer's disease.

A series of novel propargylamine-modified pyrimidinylthiourea derivatives (1-3) were designed and synthesized as multifunctional agents for Alzheimer's disease (AD) therapy, and their potential was evaluated through various biological experiments. Among these derivatives, compound 1b displayed good selective inhibitory activity against AChE (vs BuChE, IC50 = 0.324 µM, SI > 123) and MAO-B (vs MAO-A, IC50 = 1.427 µM, SI > 35). Molecular docking study showed that the pyrimidinylthiourea moiety of 1b could bind to the catalytic active site (CAS) of AChE, and the propargylamine moiety interacted directly with the flavin adenine dinucleotide (FAD) of MAO-B. Moreover, 1b demonstrated mild antioxidant ability, good copper chelating property, effective inhibitory activity against Cu2+-induced Aß1-42 aggregation, moderate neuroprotection, low cytotoxicity, and appropriate blood-brain barrier (BBB) permeability in vitro and was capable of ameliorating scopolamine-induced cognitive impairment in mice. These results indicated that 1b has the potential to be a multifunctional candidate for the treatment of Alzheimer's disease.

Preparation of a polylactic acid knitting mesh for pelvic floor repair and in vivo evaluation.

The health warning report by the Food and Drug Administration (FDA) in 2011 has drawn attention to the need for developing a suitable bio-scaffold for repairing female pelvic from disease. This work prepared a pure polylactic acid knitting mesh (PPA) and compared its structure and properties with a commercial mesh - Surgimesh® Prolapse (SP; Aspide Medical, France). Mechanical tests showed that the PPA mesh was stronger than SP with higher breaking strength and bursting strength. The in vivo property of PPA was evaluated with an animal model. Both PPA-tissue and SP-tissue were tested to have lower strength and initial elastic modulus; tissue layer played a vital role in the bio-mechanics, especially after 3 months of implantation. New tissues on the surface of PPA grew faster and thicker than that on SP at each observation period. The final shrinkage rate of PPA (2.13 ± 0.41%) was much lower than that of SP (30.35 ± 1.7%). Obvious adhesion phenomenon was observed on both PPA and SP meshes at each test point. Two meshes showed different adhesion level, that PPA was assessed of severe adhesion, even causing host tissue rupture. By histological evaluation, both PPA and SP groups showed obvious tissue inflammation reaction evidenced by rich lymphocytes. However the surrounding tissues on the PPA recovered better, with higher inflammation response scores and presence of significant vascularization and adipogenesis after six months of implantation.

Age-stratified analysis of long-term outcomes of transvaginal mesh repair for treatment of pelvic organ prolapse.

OBJECTIVE: To investigate long-term outcomes after transvaginal mesh repair among patients with pelvic organ prolapse in different age groups. METHODS: A retrospective cohort study was conducted among women who underwent transvaginal mesh repair with polypropylene mesh for pelvic organ prolapse of stage II or higher between January 2007 and November 2011 at a center in Shanghai, China. Patients were invited to attend a follow-up appointment between July 2014 and May 2015. Surgical outcomes were compared among three age groups (≤59, 60-74, and ≥75 years), and quality-of-life questionnaires were evaluated. Multivariate logistic regression was used to identify risk factors associated with recurrent prolapse and mesh exposure. RESULTS: Among 158 patients, 143 (90.5%) were objectively cured and 149 (94.3%) were subjectively cured at follow-up. Surgical outcomes were similar across all age groups. Significant improvements were observed on the Pelvic Floor Distress Inventory across all applicable subscales in all age groups (P<0.001 for all). Multivariate logistic regression showed that an active postoperative sex life significantly increased the risk of mesh exposure (odds ratio 11.89, 95% confidence interval 1.08-131.48; P=0.043). CONCLUSION: Transvaginal mesh repair was found to be a safe and effective technique for treating pelvic organ prolapse among women of all ages. An active postoperative sex life increased the odds of mesh exposure.

MicroRNA-130b functions as a tumor suppressor by regulating RUNX3 in epithelial ovarian cancer.

AIM: To evaluate the clinical significance of microRNA (miR)-130b-Runt domain transcription factor (RUNX3) axis and its effects on oncogenic phenotypes of human epithelial ovarian cancer (EOC). METHODS: QRT-PCR was performed to detect the expression of miR-130b and RUNX3 mRNA in 100 EOC and 20 normal ovarian tissues. The associations between miR-130b and/or RUNX3 expression and various clinicopathological features of EOC patients were statistically analyzed. Then, the effects of miR-130b-RUNX3 axis on migration and invasion of EOC cells were assessed in vitro. RESULTS: miR-130b expression was downregulated, while RUNX3 mRNA was upregulated, in EOC tissues compared to normal ovarian tissues (both P=0.001). Importantly, the expression level of miR-130b in EOC tissues was negatively correlated with that of RUNX3 mRNA significantly. Additionally, miR-130b-low and/or RUNX3-high expression were all closely correlated with advanced International Federation of Gynecology and Obstetrics (FIGO) stage (all P<0.05). Moreover, overexpression of miR-130b reduced the expression of RUNX3 and inhibited cancer cell migration and invasion of EOC cells, whereas knockdown of miR-130b increased the expression of RUNX3 and promoted cancer cell migration and invasion of EOC cells. After that, the impaired motility of the miR-130b overexpression cells was recovered partly by the expression of RUNX3. Furthermore, the knockdown of RUNX3 also gave rise to a decrease in cell migration and invasion. CONCLUSION: Our data reveal that the dysregulation of miR-130b-RUNX3 axis may play important roles in EOC development and progression, and the loss of miR-130b may contribute to the malignant biological behavior of EOC cells via regulating the expression of RUNX3, implying their potentials as promising markers for predicting EOC progression and as candidate targets for gene therapy.

Randomized controlled trial comparing letrozole with laparoscopic ovarian drilling in women with clomiphene citrate-resistant polycystic ovary syndrome.

The aim of the present study was to compare the reproductive outcomes of letrozole and laparoscopic ovarian drilling (LOD) in women with clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS). A total of 141 women with CC-resistant PCOS were enrolled and randomly allocated into groups A and B. Group A (n=71) received 2.5 mg letrozole from days 5 to 10 of menses for up to six cycles, and group B (n=70) underwent LOD. A 6-month follow-up was performed. No statistically significant difference was found in the baseline clinical characteristics and the major serum hormone profiles, including luteinizing hormone, follicle-stimulating hormone, estradiol and free testosterone, between the two groups. Women receiving letrozole had a lower rate of spontaneous abortion (6.9 vs. 15.8%) and higher clinical pregnancy (40.8 vs. 27.1%) and live birth (38.0 vs. 22.9%) rates; however, the differences were not statistically significant. Letrozole had superior reproductive outcomes compared with LOD in women with CC-resistant PCOS; therefore, letrozole could be used as the first-line treatment for women with CC-resistant PCOS.

Fab fragment glycosylated IgG may play a central role in placental immune evasion.

STUDY QUESTION: How does the placenta protect the fetus from immune rejection by the mother? SUMMARY ANSWER: The placenta can produce IgG that is glycosylated at one of its Fab arms (asymmetric IgG; aIgG) which can interact with other antibodies and certain leukocytes to affect local immune reactions at the junction between the two genetically distinct entities. WHAT IS KNOWN ALREADY: The placenta can protect the semi-allogenic fetus from immune rejection by the immune potent mother. aIgG in serum is increased during pregnancy and returns to the normal range after giving birth. aIgG can react to antigens to form immune complexes which do not cause a subsequent immune effector reaction, including fixing complements, inducing cytotoxicity and phagocytosis, and therefore has been called 'blocking antibody'. STUDY DESIGN, SIZE, DURATION: Eighty-eight human placentas, four trophoblast cell lines (TEV-1, JAR, JEG and BeWo), primary culture of human placental trophoblasts and a gene knock-out mouse model were investigated in this study. PARTICIPANTS/MATERIALS, SETTING, METHODS: The general approach included the techniques of cell culture, immunohistochemistry, in situ hybridization, immuno-electron microscopy, western blot, quantitative PCR, protein isolation, glycosylation analysis, enzyme digestion, gene sequencing, mass spectrophotometry, laser-guided microdissection, enzyme-linked immunosorbent assay, pulse chase assay, double and multiple staining to analyze protein and DNA and RNA analysis at the cellular and molecular levels. MAIN RESULTS AND THE ROLE OF CHANCE: Three major discoveries were made: (i) placental trophoblasts and endothelial cells are capable of producing IgG, a significant portion of which is aberrantly glycosylated at one of its Fab arms to form aIgG; (ii) the asymmetrically glycosylated IgG produced by trophoblasts and endothelial cells can react to immunoglobulin molecules of human, rat, mouse, goat and rabbit at the Fc portion; (iii) asymmetrically glycosylated IgG can react to certain leukocytes in the membrane and cytoplasm, while symmetric IgG from the placenta does not have this property. LIMITATIONS, REASONS FOR CAUTION: Most of the experiments were performed in vitro. The proposed mechanism calls for verification in normal and abnormal pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: This study identified a number of new phenomena suggesting that aIgG produced by the placenta would be able to react to detrimental antibodies and leukocytes and interfere with their immune reactions against the placenta and the fetus. This opens a new dimension for further studies on pregnancy physiology and immunology. Should the mechanism proposed here be confirmed, it will have a direct impact on our understanding of the physiology and pathology of human reproduction and offer new possibilities for the treatment of many diseases including spontaneous abortion, infertility and pre-eclampsia. It also sheds light on the mechanism of immune evasion in general including that of cancer.