Distinct effect of potassium 2-(l-hydroxypentyl) - benzoate on hippocampal neurons, synapses and dystrophic axons in APP/PS1 mice

OBJECTIVE To study the protective effect of potassium 2-(l-hydroxypentyl)-benzoate(PHPB) on hippocampal neurons,synapses and dystrophic axons in APP/PS1 mice.METHODS Ten-month-old male APP/PS1 transgenic mice and age-matched wild-type mice were randomly divided into three groups:wild-type group(WT Con group,n=10),APP/PS1 group(Tg Con group,n=10) and PHPB treated APP/PS1 group(PHPB group,n=10).PHPB group received 30 mg · kg-1 PHPB by oral gavage once daily for 3 months.WT Con group and Tg Con group received the same volume of water.Three months later,mice were sacrificed for biochemical and pathological testing such as transmission electron microscopy,Golgi staining and Western boltting analysis.RESULTS Under the transmission electron microscope,most hippocampal neurons and subcel ular organel es in WT Con group exhibited normal morphology.However,the degenerative changes were observed in Tg Con group such as nuclear fragmentation,mitochondrial swelling,ribosomes detachment and autophagic vacuoles accumulation.The hippocampal synapses number and the thickness of postsynaptic density(PSD) were significantly decreased in Tg Con group compared with the WT Con group(P<0.05).After PHPB treatment,the degenerative changes in APP/PS1 mice were alleviated to some extent.The synapse number has been elevated significantly(P<0.05) and the PSD has been thickened as well.Golgi staining showed that the spine density of secondary and tertiary apical dendritic branches was significantly decreased in CA1 and DG areas of Tg Con group(P<0.05).Sholl analysis revealed a decrease of dendritic complexity in Tg Con group compared with WT Con group(P<0.05).These abnormalities were alleviated to some extent after PHPB treatment.Western blotting study showed that the protein levels of synaptic marker PSD-95 and synaptophysin were significantly decreased in the hippocampus of Tg Con group(P<0.05).A significant increase of PSD-95(P<0.05) and a slight increase of SYP were observed after the PHPB treatment.Besides,we found a significant increase in the ratio of LC3-Ⅱ/LC3-Ⅰ in Tg Con group compared with the WT Con group(P<0.01) and the relevant improvement after PHPB treatment(P<0.05),which showed the regulatory effect of PHPB on autophagy impairment.CONCLUSION PHPB showed protective effects on hippocampal neurons,synapses and dystrophic axons in APP/PS1 mice,which might help explain its role on cognitive improvement in Alzheimer disease treatment.

Misdiagnosed dystrophic epidermolysis bullosa pruriginosa:A case report

BACKGROUND Dystrophic epidermolysis bullosa pruriginosa(DEB-Pr)is a rare subtype of DEB,characterized by recurrent pruritus of the extremities,pruritus papules,nodules,and mossy-like plaques.To date,fewer than 100 cases have been reported.We report a misdiagnosed 30-year-old man with sporadic late-onset DEB-Pr who responded well to tacrolimus treatment,thereby serving as a guide to correct diagnosis and treatment.CASE SUMMARY A 30-year-old man presented with recurrent itching plaques of 1-year duration in the left tibia that aggravated and involved both legs and the back.Examination revealed multiple symmetrical,purple,and hyperpigmented papules and nodules with surface exfoliation involving the tibia and dorsum of the neck with negative Nissl's sign,no abnormalities in the skin,mucosa,hair,or fingernail,and no local lymph node enlargement.Blisters were never reported prior to presentation.Serum immunoglobulin E level was 636 IU/mL.Clinical manifestations suggested DEB-Pr.Histological examination showed subepidermal fissure,scar tissue,and milia.Direct immunofluorescence showed no obvious abnormalities.However,we were unable to perform electron microscopy or genetic research following his choice.We treated him with topical tacrolimus.After 2 wk,the itching alleviated,and the skin lesions began to subside.No adverse reactions were observed during treatment.CONCLUSION Topical tacrolimus is a safe treatment option for patients with DEB-Pr and can achieve continuous relief of severe itching.

Dystrophic Calcinosis in the Hands of a Patient with Rheumatoid Arthritis and Secundary Sjogren’s Syndrome

Salts of calcium phosphate and inorganic phosphate are normally found in serum and extracellular fluids, balancing through poorly understood factors that prevent abnormal tissue deposition of these minerals. However, in those tissues that are injured, especially due to chronic inflammatory processes, a predisposition to the deposition of these minerals is developed, triggering what has been called Dystrophic Calcinosis (DC), common in different Connective Tissue Diseases (CTD), especially dermatomyositis and scleroderma, but there is no a frecuent association with diseases like Rheumatoid Arthritis (RA) and Sj?gren Syndrome (SS). We report a case of a female patient of 63 years old with RA and Secundary SS who presents with DC in the hands and no evidence of other connective tissue.

Rbm8a regulates neurogenesis and reduces Alzheimer's disease-associated pathology in the dentate gyrus of 5×FAD mice

Alzheimer’s disease is a prevalent and debilitating neurodegenerative condition that profoundly affects a patient’s daily functioning with progressive cognitive decline,which can be partly attributed to impaired hippocampal neurogenesis.Neurogenesis in the hippocampal dentate gyrus is likely to persist throughout life but declines with aging,especially in Alzheimer’s disease.Recent evidence indicated that RNA-binding protein 8A(Rbm8a)promotes the proliferation of neural progenitor cells,with lower expression levels observed in Alzheimer’s disease patients compared with healthy people.This study investigated the hypothesis that Rbm8a overexpression may enhance neurogenesis by promoting the proliferation of neural progenitor cells to improve memory impairment in Alzheimer’s disease.Therefore,Rbm8a overexpression was induced in the dentate gyrus of 5×FAD mice to validate this hypothesis.Elevated Rbm8a levels in the dentate gyrus triggered neurogenesis and abated pathological phenotypes(such as plaque formation,gliosis reaction,and dystrophic neurites),leading to ameliorated memory performance in 5×FAD mice.RNA sequencing data further substantiated these findings,showing the enrichment of differentially expressed genes involved in biological processes including neurogenesis,cell proliferation,and amyloid protein formation.In conclusion,overexpressing Rbm8a in the dentate gyrus of 5×FAD mouse brains improved cognitive function by ameliorating amyloid-beta-associated pathological phenotypes and enhancing neurogenesis.

Atrium of stone:A case of confined left atrial calcification without hemodynamic compromise

Dystrophic cardiac calcification is often associated with conditions causing systemic inflammation and when present,is usually extensive,often encompassing multiple cardiac chambers and valves.We present an unusual case of dystrophic left atrial calcification in the setting of end stage renal disease on hemodialysis diagnosed by echocardiography and computed tomography.Significant calcium deposition is confined within the walls of the left atrium with no involvement of the mitral valve,and no hemodynamic effects.

Tree encroachment into savannas alters soil microbiological and chemical properties facilitating forest expansion

Abstract Forests have been expanding over typical savanna sites for the past 3000 years in the Neotropics. Such invasion can produce a series of environmental modifications on typical savanna; however, it remains unclear how modifications in soil properties, caused by the encroachment of woody species, facilitate the expansion of forest ecosystems under dystrophic conditions. Here we examined chemical and microbiological changes associ- ated with tree encroachment in oxisols of a Neotropical Savanna at Assis Ecological Station, Southeastern Brazil. We predicted that tree encroachment caused by typical forest species would cause significant changes in the chemical and microbiological properties of savanna soils. Soils were sampled at Assis Ecological Station, from savanna sites differing in tree encroachment （typical, dense and forested savanna） caused by decades of fire exclusion. We analysed vegetation leaf area index and leaf litter volume deposited in the studied plots and chemical （pH,organic matter, P, K, Ca, Mg, A1, NO3-, NH4＋） and microbiological （microbial C biomass and dehydrogenase activity） properties of soils under distinct encroachment conditions. Most soil chemical properties did not change along the tree encroachment gradient; however, total P, soil organic matter, soil microbial C and dehydrogenase activity increased from typical savanna to forested savanna. The changes in soil organic matter and dehydrogenase activity were correlated with the values of leaf area index and litter volume along the encroachment gradient. Our results demonstrate that forest species can increase carbon and phosphorus supplies in tropical savanna soils.