Nonreciprocal and Nonvolatile Electric-Field Switching of Magnetism in van der Waals Heterostructure Multiferroics.

Multiferroic materials provide robust and efficient routes for the control of magnetism by electric fields, which have been diligently sought after for a long time. Construction of two-dimensional (2D) vdW multiferroics is a more exciting endeavor. To date, the nonvolatile manipulation of magnetism through ferroelectric polarization still remains challenging in a 2D vdW heterostructure multiferroic. Here, we report a van der Waals (vdW) heterostructure multiferroic comprising the atomically thin layered antiferromagnet (AFM) CrI3 and ferroelectric (FE) α-In2Se3. We demonstrate anomalously nonreciprocal and nonvolatile electric-field control of magnetization by ferroelectric polarization. The nonreciprocal electric control originates from an intriguing antisymmetric enhancement of interlayer ferromagnetic coupling in the opposite ferroelectric polarization configurations of α-In2Se3. Our work provides numerous possibilities for creating diverse heterostructure multiferroics at the limit of a few atomic layers for multistage magnetic memories and brain-inspired in-memory computing.

Human antigen R-regulated mRNA metabolism promotes the cell motility of migrating mouse neurons.

Neocortex development during embryonic stages requires the precise control of mRNA metabolism. Human antigen R (HuR) is a well-studied mRNA-binding protein that regulates mRNA metabolism, and it is highly expressed in the neocortex during developmental stages. Deletion of HuR does not impair neural progenitor cell proliferation or differentiation, but it disturbs the laminar structure of the neocortex. We report that HuR is expressed in postmitotic projection neurons during mouse brain development. Specifically, depletion of HuR in these neurons led to a mislocalization of CDP+ neurons in deeper layers of the cortex. Time-lapse microscopy showed that HuR was required for the promotion of cell motility in migrating neurons. PCR array identified profilin 1 (Pfn1) mRNA as a major binding partner of HuR in neurons. HuR positively mediated the stability of Pfn1 mRNA and influenced actin polymerization. Overexpression of Pfn1 successfully rescued the migration defects of HuR-deleted neurons. Our data reveal a post-transcriptional mechanism that maintains actin dynamics during neuronal migration.

Association between Neutrophil Levels on Admission and All-Cause Mortality in Geriatric Patients with Hip Fractures: A Prospective Cohort Study of 2,589 Patients.

Objective: To evaluate the association between neutrophil levels and all-cause mortality in geriatric hip fractures. Methods: Elderly patients with hip fractures were screened between January 2015 and September 2019. Demographic and clinical characteristics of the patients were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between neutrophil levels and mortality. Analyses were performed using Empower Stats and R software. Results: A total of 2,589 patients were included in this study. The mean follow-up period was 38.95 months. During the study period, 875 (33.80%) patients died due to various causes. Linear multivariate Cox regression models showed that neutrophil levels were associated with mortality after adjusting for confounding factors, when neutrophil concentration increased by 1∗109/L, the mortality risk increased by 3% (HR = 1.03, 95% CI: 1.00-1.06, and P=0210). Neutrophil concentration was used as a categorical variable; we only found statistically significant differences when neutrophil levels were high (HR = 1.27, 95% CI:1.05-1.52, and P=0.0122). In addition, the results are stable in P for trend and propensity score matching sensitivity analysis. Conclusions: Neutrophil levels are associated with mortality in geriatric hip fractures and could be considered a predictor of death risk in the long-term. This study is registered with the Chinese Clinical Trial Registry (ChiCTR) as number ChiCTR2200057323.

Thermodynamic Regulation of Dendrite-Free Li Plating on Li3Bi for Stable Lithium Metal Batteries.

Rechargeable batteries with metallic lithium (Li) anodes are attracting ever-increasing interests because of their high theoretical specific capacity and energy density. However, the dendrite growth of the Li anode during cycling leads to poor stability and severe safety issues. Here, Li3Bi alloy coated carbon cloth is rationally chosen as the substrate of the Li anode to suppress the dendrite growth from a thermodynamic aspect. The adsorption energy of a Li atom on Li3Bi is larger than the cohesive energy of bulk Li, enabling uniform Li nucleation and deposition, while the high diffusion barrier of the Li atom on Li3Bi blocks the migration of adatoms from adsorption sites to the regions of fast growth, which further ensures uniform Li deposition. With the dendrite-free Li deposition, the composite Li/Li3Bi anode enables over 250 cycles at an ultrahigh current density of 20 mA cm-2 in a symmetrical cell and delivers superior electrochemical performance in full batteries.

HuR in the Medial Prefrontal Cortex is Critical for Stress-Induced Synaptic Dysfunction and Depressive-Like Symptoms in Mice.

Chronic stress has been observed to increase the risk of developing depression and induce neuronal alterations of synaptic plasticity, yet the underlying molecular mechanisms remain unclear. Here, we found that the ubiquitously expressed RNA-binding protein HuR was up-regulated in the medial prefrontal cortex (mPFC) of mice following chronic stress. In adult mice, AAV-Cre-mediated knockout of HuR in the mPFC prevented anxiety-like and depression-like behaviors induced by chronic stress. HuR was also required for the stress-induced dendritic spine loss and synaptic transmission deficits. Moreover, HuRflox/flox;Nex-Cre mice, which induce HuR loss of function from embryonic development, exhibited enhanced synaptic functions. Notably, we ascertained RhoA signaling to be regulated by HuR and involved in the modulation of structural synaptic plasticity in response to chronic stress. Our results demonstrate HuR is a critical modulator for the regulation of stress-induced synaptic plasticity alterations and depression, providing a potential therapeutic target for the treatment of depressive disorders.

BMCMDA: a novel model for predicting human microbe-disease associations via binary matrix completion.

BACKGROUND: Human Microbiome Project reveals the significant mutualistic influence between human body and microbes living in it. Such an influence lead to an interesting phenomenon that many noninfectious diseases are closely associated with diverse microbes. However, the identification of microbe-noninfectious disease associations (MDAs) is still a challenging task, because of both the high cost and the limitation of microbe cultivation. Thus, there is a need to develop fast approaches to screen potential MDAs. The growing number of validated MDAs enables us to meet the demand in a new insight. Computational approaches, especially machine learning, are promising to predict MDA candidates rapidly among a large number of microbe-disease pairs with the advantage of no limitation on microbe cultivation. Nevertheless, a few computational efforts at predicting MDAs are made so far. RESULTS: In this paper, grouping a set of MDAs into a binary MDA matrix, we propose a novel predictive approach (BMCMDA) based on Binary Matrix Completion to predict potential MDAs. The proposed BMCMDA assumes that the incomplete observed MDA matrix is the summation of a latent parameterizing matrix and a noising matrix. It also assumes that the independently occurring subscripts of observed entries in the MDA matrix follows a binomial model. Adopting a standard mean-zero Gaussian distribution for the nosing matrix, we model the relationship between the parameterizing matrix and the MDA matrix under the observed microbe-disease pairs as a probit regression. With the recovered parameterizing matrix, BMCMDA deduces how likely a microbe would be associated with a particular disease. In the experiment under leave-one-out cross-validation, it exhibits the inspiring performance (AUC = 0.906, AUPR =0.526) and demonstrates its superiority by ~ 7% and ~ 5% improvements in terms of AUC and AUPR respectively in the comparison with the pioneering approach KATZHMDA. CONCLUSIONS: Our BMCMDA provides an effective approach for predicting MDAs and can be also extended to other similar predicting tasks of binary relationship (e.g. protein-protein interaction, drug-target interaction).

TMFUF: a triple matrix factorization-based unified framework for predicting comprehensive drug-drug interactions of new drugs.

BACKGROUND: A significant number of adverse drug reactions is caused by unexpected Drug-drug interactions (DDIs). The identification of DDIs becomes crucial before the co-prescription of multiple drugs is made. Such a task in clinics or in drug discovery usually requires high costs and numerous limitations, while computational approaches are able to predict potential DDIs effectively by utilizing diverse drug attributes (e.g. side effects). Nevertheless, they're incapable when required to predict enhancive and degressive DDIs, which change increasingly and decreasingly the pharmacological behavior of interacting drugs respectively. The pharmacological change of DDIs is one of the most important factors when making a multi-drug prescription. RESULTS: In this work, we design a Triple Matrix Factorization-based Unified Framework (TMFUF) to address the above issue. By leveraging a group of side effect entries of drugs, TMFUF achieves the inspiring result (AUC = 0.842 and AUPR = 0.526) in the case of conventional DDI prediction under the traditional screening task. In the comparison with two state-of-the-art approaches, TMFUF demonstrates it superiority by ~ 7% and ~ 20% improvement in terms of AUC and AUPR respectively. More importantly, TMFUF shows its ability in the comprehensive DDI prediction under different screening tasks. Finally, a utilization TMFUF reveals the significant pairs of side effects, which contribute to form enhancive and degressive DDIs, for further clinical validation. CONCLUSIONS: The proposed TMFUF is first capable to predict both conventional binary DDIs and comprehensive DDIs such that it captures the pharmacological changes caused by DDIs. Furthermore, it provides a unified solution of DDI prediction for two screening scenarios, which involves newly given drugs having no prior interaction. Another advantage is its ability to indicate how significantly the pairs of drug features contribute to form DDIs.

Modulating the phase transition between metallic and semiconducting single-layer MoS2 and WS2 through size effects.

The first-principles calculations are performed to investigate the electronic properties and the atomic mechanism of the single layer MoS2 or WS2 homo-junction structure. The results reveal that both the stability and electronic structure of the homo-junction structure are greatly affected by the type of boundaries, which connect the different phase structures, either the semiconducting hexagonal (H) structure or the metallic trigonal (T) structure. Through tuning the size of the lateral homo-junction structure of either MoS2 or WS2, the phase transformation between H and T can occur. Interestingly, the electronic structures of homo-junction structures can be tuned between the metal and the semiconductor by changing the size of the nanoribbons.

Interferon-induced transmembrane protein 3 in the hippocampus: a potential novel target for the therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy.

Objective: This study aims to explore whether interferon-induced transmembrane protein 3 (IFITM3) is involved in recombinant human brain natriuretic peptide (rhBNP)-mediated effects on sepsis-induced cognitive dysfunction in mice. Methods: The cellular localization and expression level of IFITM3 in the hippocampus were detected. The IFITM3 overexpression was achieved using an intracranial stereotactic system to inject an adeno-associated virus into the hippocampal CA1 region of mice. Field experiments, an elevated plus maze, and conditioned fear memory tests assessed the cognitive impairment in rhBNP-treated septic mice. Finally, in the hippocampus of septic mice, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining and Immunoblot were used to detect changes in the protein expression of cleaved Caspase-8 and cleaved Caspase-3 in apoptosis-related pathways, and toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) p65 in inflammatory pathways. Results: Fourteen days after cecal ligation and puncture (CLP) surgery, IFITM3 localized in the plasma membrane and cytoplasm of the astrocytes in the hippocampus of septic mice, partially attached to the perivascular and neuronal surfaces, but not expressed in the microglia. The expression of IFITM3 was increased in the astrocytes and neurons in the hippocampus of septic mice, which was selectively inhibited by the administration of rhBNP. Overexpression of IFITM3 resulted in elevated anxiety levels and long-term learning and memory dysfunction, completely abolished the therapeutic effect of rhBNP on cognitive impairment in septic mice, and induced an increase in the number of neuronal apoptosis in the hippocampal CA1 region. The expression levels of cleaved Caspase-3 and cleaved Caspase-8 proteins were significantly increased in the hippocampus, but the expression levels of TLR4 and NF-κB p65 were not increased. Conclusion: The activation of IFITM3 may be a potential new target for treating sepsis-associated encephalopathy (SAE), and it may be one of the key anti-apoptotic mechanisms in rhBNP exerting its therapeutic effect, providing new insight into the clinical treatment of SAE patients.

Corrigendum: Interferon-induced transmembrane protein 3 in the hippocampus: a potential novel target for the therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy.

[This corrects the article DOI: 10.3389/fnmol.2023.1182005.].

[Clinical and pathologic features of tubulocystic carcinoma of kidney].

OBJECTIVE: To investigate clinicopathological features and differential diagnosis of tubulocystic carcinoma of the kidney. METHODS: The clinical features, histological and immunohistochemical findings were analyzed in 3 cases of tubulocystic carcinoma of the kidney, along with review of the related literatures. RESULTS: Three patients were males with a mean age of 59 years old (range from 44 to 71 years). All presented with no symptom and their tumors were found during routine examination. The tumor size ranged from 1.5 to 5.0 cm in greatest dimension. The tumors were grossly well-circumscribed without capsules and exhibited a spongy cut surface. Microscopically, all three tumors were composed of tubules and cysts of varying sizes separated by thin fibrous septa. The epithelial lining cells were flat, cuboidal and columnar, with often a hobnail-like appearance characterized by abundant eosinophilic cytoplasm with prominent nucleoli. Two cases showed focal clear cytoplasm. One of the three cases coexisted with a papillary renal cell carcinoma. Immunohistochemically, all 3 cases showed positivity for pan-CK, vimentin, CK19, CD10, P504S, and focal positivity for 34ßE12. Two cases showed focal positivity for CK7. CONCLUSIONS: Tubulocystic carcinoma of the kidney is a rare kidney neoplasm and occurs predominantly in males. The tumor is characterized by gross spongy appearance and microscopic cysts and tubules often lined by hobnail-like cells and separated by thin fibrotic stroma. The differential diagnosis mainly includes other lesions of the kidney that have a multicystic growth pattern.

[Clinicopathologic analysis of intestinal follicular lymphoma first presenting with gastrointestinal symptoms].

OBJECTIVE: To study the clinical features, endoscopic findings, pathologic diagnosis and treatment options of intestinal follicular lymphoma first presenting with gastrointestinal symptoms. METHODS: The clinical features, pathologic findings and follow-up data were retrospectively studied in 9 cases of intestinal follicular lymphoma. Immunohistochemical study for CD3, CD5, CD20, CD21, Ki-67, bcl-2, bcl-6, CD10 and cyclin D1 was carried out. RESULTS: Seven of the 9 patients were females and two were males. The age of patients ranged from 5 to 60 years (mean = 44 years). The clinical manifestations included abdominal pain (5 cases), blood in stool (3 cases) and abdominal distension (1 case). The commonest site of involvement was ileocecal region (6/9). Endoscopic examination had been carried out in 6 patients and all showed the presence of multiple polyps. Five cases had undergone endoscopic biopsy. Histologic examination of the endoscopic biopsies showed lymphoma cells located mainly in mucosal layer, forming vague nodules with ill-defined boundaries. Plasma cells and eosinophils were not conspicuous. Immunohistochemically, the tumor cells in all cases diffusely expressed CD20, CD10 and bcl-2. The staining for CD3, CD5 and cyclin D1 was negative. Lymphoid cells with weak CD10-positivity were identified in the interfollicular regions. Four cases were treated with surgical resection and chemotherapy. The other 3 cases received chemotherapy only and the remaining cases were treated conservatively. All of them were still alive on follow up. CONCLUSIONS: Primary intestinal follicular lymphoma affects predominantly elderly patients and has a female predilection. The commonest site of involvement is ileocecal region. Endoscopic examination shows polypoid changes. The disease often runs a relatively indolent clinical course. The prognosis is better than that of primary nodal follicular lymphoma.

Bladder paraganglioma after kidney transplantation: A case report.

BACKGROUND: Kidney transplantation is associated with an increased risk of tumors in the urinary bladder. Among all the pathological types of tumors in the bladder, paraganglioma, which arises from extra-adrenal paraganglia and consists of chromaffin cells, is rare. Paragangliomas might cause severe clinical symptoms due to catecholamine hypersecretion or mass compression. Bladder paragangliomas are rare, especially those appearing after kidney transplantation. Here, we report a case of bladder paraganglioma developing after kidney transplantation. CASE SUMMARY: A 63-year-old woman received a kidney transplant 12 years ago and took oral immunosuppressants (cyclosporine, mizoribine, and methylprednisolone) for regular post-transplant treatment. The patient felt no discomfort and she came to the hospital for a routine checkup. A mass located in the bladder was incidentally discovered by computed tomography, and she underwent surgical treatment. A 2 cm × 2 cm invasive mass was found in the trigone of the bladder and the mass was removed. The diagnosis of paraganglioma was confirmed by morphology and immunophenotyping. The patient had a good prognosis and is still alive. CONCLUSION: Paraganglioma can grow in the bladder, which might cause no clinical symptoms. The diagnosis mainly depends on morphology and immunophenotyping. Surgical resection is an important treatment option for such patients.

[Loss of pan-T cell antigens CD2, CD3, CD5 and CD7 in Kikuchi's disease].

OBJECTIVE: To study the possible loss of pan-T cell antigens CD2, CD3, CD5 and CD7 in Kikuchi's disease and to evaluate the role of T cell antigen loss in distinguishing benign from malignant T-cell lymphoid lesions. METHODS: Formalin-fixed and paraffin-embedded tissues of 33 cases of Kikuchi's disease and 15 cases of reactive lymphoid hyperplasia were studied by EliVision immunohistochemical staining for CD2, CD3, CD5 and CD7. RESULTS: Twenty-four of the 33 (72.7%) cases of Kikuchi's disease lost one or more of the pan-T cell antigens, including the loss of CD5 only (13 cases), CD7 only (1 case), CD2 only (1 case), CD2 and CD7 (2 cases), CD5 and CD7 (4 cases), CD2 and CD5 (2 cases), and CD2, CD7 and CD5 (1 case). Amongst these cases, the commonest antigen loss was CD5 (20 cases, 60.6%), followed by CD7 (8 cases, 24.2%) and CD2 (6 cases, 18.2%). Compared with the xanthomatous subtype of Kikuchi's disease, the loss of antigens was more commonly seen in the proliferative and necrotizing subtypes. Analysis of follow-up data showed that the loss of antigens in Kikuchi's disease was not significantly associated with the prognosis. In reactive lymphoid hyperplasia, the expression of CD2, CD3, CD5 and CD7 was seen in all cases with similar intensity, with no obvious pan-T cell antigen loss. CONCLUSION: Loss of one or more pan-T cell antigens in Kikuchi's disease is demonstrated in present study, suggesting that the immunophenotypic pattern is not unique in T cell lymphoma.

[Screening the proteins of organophosphoms ester-induced delayed neurotoxicity in the cerebral tissue of hens exposed to tri-ortho-cresyl phosphate].

OBJECTIVE: To screen the proteins with differential expression levels in the cerebral tissue of hens exposed to tri-ortho-cresyl phosphate (TOCP), and to provide target proteins for studying the mechanism of organophosphoms ester-induced delayed neurotoxicity (OPIDN). METHODS: Thirty two adult Roman hens were randomly divided into four groups: TOCP group was exposed to 1000 mg/kg TOCP, PMSF group was exposed to 40 mg/kg PMSF, PMSF plus TOCP group was exposed to 40 mg/kg PMSF and after 24 h exposed to 1000 mg/kg TOCP, control group was exposed to normal saline. All hens exposed to chemicals by gastro-intestine for 5 days were sacrificed, and the cerebral tissue were dissected and homogenized in ice bath. Total proteins extracted from the cerebral tissue were separated by isoelectric focusing as the first dimension and SDS-PAGE as the second dimension. The 2-DE maps were visualized after silver staining and analyzed by Image Master 2D software. At last ,the expressed protein spots were identified by Mass spectrometry. RESULTS: From total proteins in TOCP group, the PMSF plus TOCP group and PMSF group, 1185, 1294 and 1063 spots were detected, respectively. One thousand three hundred thirty two spots from total proteins in control group were detected. The match rates of protein spots in TOCP group, the PMSF plus TOCP group and PMSF group were 78.32 %, 79.56 % and 80.93%, respectively. There were 235 protein spots with differential expression levels between TOCP group and control group, which included 158 up regulation spots and 77 down regulation spots. According to the PMSF features, there were 102 spots with differential expression levels between TOCP group and control group and without differential expression levels between TOCP group and PMSF plus TOCP group, among them there were 13 spots with 4 fold differential expression levels between TOCP group and control group and without differential expression levels between TOCP group and PMSF group. Seven protein spots (homer-1b, Destrin, heat shock protein 70, eukaryotic translation initiation factors, proteasome alpha1 subunit, lactate dehydrogenase B, glutamine synthetase) were detected by Mass spectrometry. CONCLUSION: There are 112 protein spots with differential expression levels of the cerebral tissue in TOCP group, which may be related to OPIDN, among them 13 protein spots with differential expression levels are associated closely with OPIDN. Seven protein spots detected by Mass spectrometry may be related to the mechanism induced by OPIDN.

[The differential expression of Stathmin in the spinal cord tissue of hens exposed to tri-o-cresyl phosphate].

OBJECTIVE: To screen the differently expressed proteins related to regulating the depolymerization of microtubules in the spinal cord of hens exposed to tri-o-cresyl phosphate (TOCP) and to provide target protein evidence for exploring the mechanisms of the delayed neurotoxicology (OPIDN) induced by organophosphorus compounds (OPs). METHODS: Forty two Roman hens were randomly divided into three groups, i.e. TOCP group treated with 1000 mg/kg TOCP; intervention group treated with 40 mg/kg phenylmethanesulfonyl fluoride (PMSF) before 1000 mg/kg TOCP treatment and control group treated with tap water. Four hens in each group were sacrificed on the 5th and 20th days after exposure, respectively. Spinal cords were separated and homogenates at low temperature, and the total proteins were extracted. The OPIDN symptoms observed and recorded in the remaining 6 hens in each group. The differently expressed proteins related to regulating the depolymerization of microtubules were screen by two-dimensional electrophoresis and mass spectroscopy (MS). RESULTS: The OPIDN symptoms appeared on the 5th day after exposure in TOCP group, which were gradually serious with time. The results by two-dimensional electrophoresis and MS showed that the Stathmin expression was downregulated 3.4 times and 2.8 times in TOCP group, respectively, as compared with the control and PMSF intervention groups. However, there was no significant difference of the Stathmin expression between control group and PMSF intervention group. CONCLUSION: The Stathmin expression in the spinal cord tissues of hens exposed to TOCP significantly downregulated. Moreover, the downregulated Stathmin expression may be related to excess polymerization of microtubules and the mechanism of OPIDN.

[Clinicopathological study on the follicular dendritic cell sarcoma].

OBJECTIVE: To investigate the clinicopathologic features and differential diagnostic methods for follicular dendritic cell sarcoma. METHODS: Histological and immunohistochemical examinations and EBER in situ hybridization were used to investigate the pathological features of 5 cases of follicular dendritic cell sarcoma, and related literature was reviewed. RESULTS: There were 3 males and 2 females with a median age of 54 years (range, 28 - 75 years). The location of lesions included lymph node (2 cases), tonsil (1 case), stomach (1 case), and liver (1 case). The growth patterns were fascicular or whorls and/or diffuse. The neoplastic cells were spindle or ovoid in shape with indistinct border and slightly eosinophilic cytoplasm. The nuclei were round, oval or spindle in shape with small distinct nucleoli. Warthin-Finkeldey-like multinucleated giant cells were detected in two cases. Mitotic figures were found in 1-22/10 HPF. Immunohistochemical staining showed that CD21 and CD23 (3 of 5), CD35 (4 of 5), D2-40 (4 of 4), and CXCL13 (3 of 4) were positive in neoplastic cells. EBER was detected in one of five cases by in situ hybridization. Four cases were followed-up for 6 approximately 25 months and no recurrence or death was observed yet. CONCLUSION: Follicular dendritic cell sarcoma is an extremely rare and should be considered as a moderately malignant tumor, and may present histological polymorphism with certain distinctive features. Immunohistochemistry is necessary in differential diagnosis to distinguish from other tumors.

Bruceine a.

The title compound, C(26)H(34)O(11), known as bruceine A, is a natural quassinoid extracted from the dried fruits of Brucea javanica. Its structure consists of five fused rings including an oxygen-containing heterocyclic ring and a lactone ring. Two intra-molecular O-H⋯O links help to establish the mol-ecular conformation. In the crystal, O-H⋯O hydrogen bonds connect the mol-ecules.

[Clinicopathologic study of juvenile granulosa cell tumor of ovary].

OBJECTIVE: To study the clinicopathologic features, diagnostic criteria and prognostic parameters of juvenile granulosa cell tumor of ovary. METHODS: The clinical and pathologic findings of 7 cases of juvenile granulosa cell tumor were retrospectively reviewed. Immunohistochemical study was carried out in 6 of these cases. The follow-up data were also analyzed. RESULTS: The mean age of the patients was 24 years (range=6 to 53 years). Four patients presented with hormonal disturbance, while 3 patients presented with abdominal pain or swelling. Six patients underwent unilateral salpingo-oophorectomy. Six cases were in stage IA and the remaining case in stage IC. Follow-up information was available in 6 patients and the duration of follow up ranged from 1 to 10 years (mean=4.3 years). Five patients remained healthy, with no evidence of tumor recurrence. One patient died of tumor metastasis one year after the diagnosis. Gross examination showed that the tumor masses ranged from 7 to 20 cm in the greatest dimension (average=13.4 cm). Four of the 7 tumors were mixed solid-cystic in appearance and 2 cases were unilocular cystic in nature. Microscopic examination showed diffuse atypical follicular structures formed by granulosa cells. The granulosa cells contained round hyperchromatic nuclei, without nuclear grooves or Call-Exner body formation (6/7). In one of the cases studied, minor foci resembling adult granulosa cell tumor were also demonstrated. The degree of cellular atypia varied (3 cases with severe atypia, 1 case with moderate atypia and 3 cases with mild atypia). The mitotic count ranged from 1 to more than 5 per 10 high-power fields. Immunohistochemical study showed diffuse positivity for vimentin (6/6). The staining for cytokeratin (AE1/AE3) and calretinin was negative. Four cases expressed CD99 and 1 case was positive for inhibin. CONCLUSIONS: Juvenile granulosa cell tumor is characterized by the presence of diffuse atypical follicular structures formed by small round cells, without nuclear grooves or Call-Exner bodies. Rare cases contain minor foci of adult granulosa cell tumor. They can be unilocular cystic in nature. The degree of nuclear atypia, mitotic activity and size of the tumor vary and do not correlate with the risk of recurrence and aggressive biologic behavior.