In Vitro and In Vivo Antiurolithic Effect of Betulinic Acid Obtained from Citharexylum mirianthum.

The study aimed to investigate the potential antiurolithic effects of extracts, fractions, and betulinic acid (BA) from Citharexylum mirianthum. In vitro analysis involved precipitating calcium oxalate (CaOx) crystals in urine. For in vivo studies, rats were divided into four groups: naive; vehicle; potassium citrate (KC); and BA. Urolithiasis was induced using ethylene glycol and ammonium chloride. After seven days, urine, blood, and kidney tissues were evaluated. The results showed that methanolic extract, hexane, dichloromethane, and ethyl acetate fractions, as well as BA, reduced CaOx crystal formation. In vivo, the vehicle-treated group exhibited reduced urinary volume and Na+ excretion, while the BA-treated group showed restored urinary volume and Na+ excretion similar to the naive group. BA also significantly reduced urinary monohydrate and dihydrate crystal formation, comparable to the KC group. Other urinary parameters remained unchanged, but plasma analysis revealed decreased Na+, K+, and Ca2+ in the KC group. Renal tissue analysis indicated reduced lipid hydroperoxides and increased reduced glutathione in all urolithiasis groups, with unchanged nitrite levels. BA treatment also improved renal corpuscle morphology. Overall, our findings demonstrate that treatment with BA effectively prevented kidney damage induced by EG+AC ingestion, thereby improving renal function in the urolithiasis model.

Protective Role of Rosmarinic Acid in Experimental Urolithiasis: Understanding Its Impact on Renal Parameters.

This study aimed to assess the ability of rosmarinic acid (RA) to prevent kidney stone formation in an ethylene glycol and ammonium chloride (EG/AC) model. There was an increase in diuresis in the normotensive (NTRs) and hypertensive rats (SHRs) treated with hydrochlorothiazide (HCTZ) and exposed to EG/AC, while RA restored urine volume in NTRs. The EG/AC groups exhibited lower urine pH and electrolyte imbalance; these parameters were not affected by any of the treatments. Both HCTZ+EG/AC and RA+EG/AC reduced calcium oxalate crystal formation in NTR and SHR urine. Kidney tissue analysis revealed alterations in oxidative stress and inflammation parameters in all EG/AC-receiving groups, with RA enhancing antioxidant defenses in SHRs. Additionally, crystals were found in the kidney histology of all EG/AC-exposed groups, with reduced Bowman's capsule areas in NTRs and SHRs. The NTR VEH+EG/AC group showed intense renal damage, while the others maintained their structures, where treatments with HCTZ and RA were fundamental for kidney protection in the NTRs. Docking analysis showed that RA exhibited good binding affinity with matrix metalloproteinase-9, phosphoethanolamine cytidylyltransferase, and human glycolate oxidase enzymes. The data disclosed herein underscore the importance of further research to understand the underlying mechanisms better and validate the potential of RA for clinical use.

Investigation of the potential anti-urolithiatic activity of Alhagi maurorum (Boiss. ) grown wild in Al-Ahsa (Eastern Province), Saudi Arabia / Investigação da potencial atividade antiurolítica de Alhagi maurorum (Boiss. ) cultivado selvagem em Al-Ahsa (Província Oriental), Arábia Saudita

The potential of Alhagi maurorum (Boiss.) aqueous extract (AME), used in traditional medicine for treatment or prevention of urolithiasis, to dissolve calcium oxalate stones in vitro was evaluated. In order to determine the litholytic potential of the extract, Calcium oxalate urinary stones were incubated during 12 weeks under continuous shaking in the presence of AME, Rowanix or NaCl 9 g/mL solution were used as controls. After the incubation period, the residual weight of the treated calculi was determined and the rate of dissolution was calculated. The medium pH variation was measured and changes in the calcium oxalate crystals at the stone surface were assessed using a scanning electron microscope (SEM). The results showed a significant dissolution effect for the extract on the kidney calculi during the experimentation period. At the end of the experiment, the percentages of calculi weight decrease were 41.23, 4.97 and 55.67% for the extract, NaCl solution and Rowanix, respectively. Gas Chromatography analysis revealed mainly the presence of the following phyto-compounds: Cyclopropenone, 2,3-diphenyl; 1-Nonadecanol; methyl-alpha-D-mannopyranoside; cis-9-Hexadecenal. These compounds unarguably play crucial roles in the health care system especially in cancer treatment and many other diseases including urolithiasis. The urinary stone dissolution, independent of medium pH, could be attributed to formation of complexes between the phytochemical compounds in the extract and the calculi.

Foi avaliado o potencial do extrato aquoso (AME) de Alhagi maurorum (Boiss.), usado na medicina tradicional para tratamento ou prevenção de urolitíase, para dissolver cálculos de oxalato de cálcio in vitro. Para determinar o potencial litolítico do extrato, cálculos urinários de oxalato de cálcio foram incubados durante 12 semanas sob agitação contínua na presença de AME, Rowanix ou solução de NaCl 9 g/mL foram usados ​​como controles. Após o período de incubação, o peso residual dos cálculos tratados foi determinado e a taxa de dissolução foi calculada. A variação do pH médio foi medida e as alterações nos cristais de oxalato de cálcio na superfície da pedra foram avaliadas usando um microscópio eletrônico de varredura (MEV). Os resultados mostraram um efeito de dissolução significativo para o extrato sobre os cálculos renais durante o período de experimentação. Ao final do experimento, os percentuais de diminuição do peso dos cálculos foram de 41,23, 4,97 e 55,67% para o extrato, solução de NaCl e Rowanix, respectivamente. A análise por cromatografia gasosa revelou principalmente a presença dos seguintes fitocompostos: Ciclopropenona, 2,3-difenil; 1-Nonadecanol; metil-alfa-D-manopiranosídeo; cis-9-hexadecenal. Esses compostos indiscutivelmente desempenham papéis cruciais no sistema de saúde, especialmente no tratamento do câncer e de muitas outras doenças, incluindo urolitíase. A dissolução do cálculo urinário, independente do pH médio, pode ser atribuída à formação de complexos entre os compostos fitoquímicos do extrato e os cálculos.

Vascular Tissues Distribution Affects Calcium and Calcium Oxalate Crystals in Fruits of Wild Tomato (Lycopersicon pimpinellifolium (L.) Mill.).

Tomato fruit is an excellent model for evaluating calcium regulation in plants since it expresses symptoms of either calcium deficiency or calcium excess. Aiming to evaluate the structure of the vascular system and its interactions with calcium and calcium oxalate crystals (CaOx), fruits of Lycopersicon pimpinellifolium were studied. Calcium levels were evaluated in basal, median, and distal pericarp portions, which were also analyzed under a light microscope to describe the structure. The L. pimpinellifolium pericarp shows idioblasts with calcium oxalate crystals. Vascular bundles of the basal pericarp show large transverse sections and abundant xylem vessels. The vascular bundles were smaller in the distal pericarp, and the xylem showed fewer and narrower vessels. The terminal bundles often consisted exclusively of phloem. Despite the differences observed in vascular bundle composition, the density of the vascular system was uniform in the pericarp as a consequence of bundle ramifications that occur at distal portions. The calcium concentration and crystal idioblasts decrease towards the apex of the fruit. The reduction in the xylem:phloem ratio seems to determine the low calcium concentration in the distal fruit portion.

Systemic oxalosis in a free-ranging green turtle (Chelonia mydas).

A female juvenile green turtle (Chelonia mydas), found alive in Guanabara Bay, Rio de Janeiro, Brazil, was weak, dehydrated and cachectic, with a healed fracture in the caudal portion of the carapace. Despite supportive treatment, the animal died after 9 days. At necropsy the main lesions were pallor of visceral organs, arthritis and deposits of whitish granular material in the wall of large arteries and the trachea. Histopathological analysis revealed mild to severe deposition of crystals, consistent with calcium oxalate, in both kidneys and the spleen, heart, small intestine, pancreas, thymus and salt gland, as well as bacterial meningitis, septic arthritis, spirorchidiasis and a fibropapilloma on the nictitating membrane. The main pathological findings were suggestive of septic shock, mainly due to the bacterial meningitis and septic arthritis, with systemic oxalosis and spirorchidiasis as contributing lesions. Although renal oxalosis has been described in green turtles as an incidental finding, presumably due to ingestion of oxalate-containing plants, this turtle had an unusual systemic deposition of oxalate crystals.

Amaranth calcium oxalate crystals are associated with chloroplast structures and proteins.

Calcium oxalate (CaOx) crystals in plants are formed in crystal idioblasts cells and have specific geometric shapes. Their proposed functions include calcium homeostasis and carbon source, among others. Amaranth is a plant that presents high tolerance to abiotic stresses and accumulates considerable amounts of CaOx crystals; however, few studies have focused on characterizing the crystals ultrastructure and none is related to identifying proteins bound to them. This information is of great interest to understand the mechanisms related to CaOx crystal formation and to support their proposed functions. Thus, this work aimed to characterize CaOx crystals in amaranth leaves. Crystals were purified and the proteins bound to them were isolated and identified by nLC-MS/MS. Leaf sections were analyzed by light and electron microscopy. The identified proteins were related to the chloroplast such as ATPb synthase, RuBisCO large subunit, and cell wall-related proteins, which were validated by immunohistochemistry and immunogold labeling. In addition, it was observed that CaOx crystal idioblasts were formed from parenchyma cells associated with mesophyll and veins, in which the thylakoid membranes of degraded chloroplasts turned into crystal chambers. These results significantly advance our understanding of the mechanisms of CaOx crystal formation and the potential function as an alternative carbon source in leaves.

Electrocrystallization of Calcium Oxalate on Electrospun PCL Fibers Loaded with Phytic Acid as a Template.

Crystallization occurs widely in living organisms where different organs could associate with the calcification process, such as the formation of calcium oxalate (CaOx) calculi in the urinary tract. However, the pathogenesis and the role of an inhibitor in the pathological processes involved in urolithiasis is poorly understood. Therefore, the use of phytic acid (PA) as an inhibitor for the organic fibrillar matrix is a novel approach to inhibit the formation of pathological CaOx crystals. Herein, electrospun polymer fiber meshes of polycaprolactone (PCL) with random (R) and aligned (A) fiber orientations containing PA were prepared by electrospinning, and their role as a 3D organic template in in vitro CaOx crystallization was investigated. CaOx crystals were generated on conductive tin indium oxide (ITO)-modified glass with R-PCL and A-PCL fibers in the presence of PA through an electrocrystallization (EC) procedure. This study provides a simple electrochemical approach to evaluate the role of PA as an inhibitor in the nucleation of pathological CaOx crystals. The resulting CaOx crystals were analyzed by chrono-potentiometry, optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). We found that PA and the fiber orientations are key factors in the nucleation and crystal growth of CaOx, achieving the stabilization of healthy CaOx crystal and the inhibition of the pathological crystal form.

Morphological and anatomical traits during development: Highlighting extrafloral nectaries in Passiflora organensis.

Passiflora organensis is a small herbaceous vine with characteristic morphological variations throughout its development. The plant bears button-shaped extrafloral nectaries exclusively in adult leaves. Extrafloral nectaries are structures that secrete nectar and play an important role in plant-animal interactions as a strategy for protecting plants against herbivory. In this work, we performed anatomical and ultrastructural studies to characterize P. organensis extrafloral nectaries during their secretory phase. We showed extrafloral nectaries in Passiflora organensis are composed of three distinct regions: nectary epidermis, nectariferous parenchyma, and subnectariferous parenchyma. Our data suggests that all nectary regions constitute a functional unit involved in nectar production and release. The high metabolic activity in the nectary cells is characterized by the juxtaposition of organelles such as mitochondria and plastids together plasmalemma. In addition, calcium oxalate crystals are frequently associated to the nectaries. An increasing concentration of calcium during leaf development and nectary differentiation was observed, corresponding to the calcium deposition as calcium oxalate crystals. This is the first description of extrafloral nectaries in Passiflora organensis that is a promising tropical model species for several studies. RESEARCH HIGHLIGHTS: The anatomical and ultrastructural characteristics and the presence of calcium oxalate crystals in the nectary tissue suggest novel strategies against herbivory in the genus Passiflora.

Extraction and quantification of oxalic acid in leaves of plant species used in the treatment of chronic non-communicable diseases / Extracción y cuantificación de ácido oxálico en hojas de especies vegetales utilizadas en el tratamiento de enfermedades crónicas no transmisibles / Extração e quantificação de ácido oxálico em folhas de espécies vegetais utilizadas no tratamento de doenças crônicas nã transmissíveis

RESUMEN Introducción: Las enfermedades crónicas no transmisibles (ECNT) tienen las tasas de mortalidad y morbilidad más altas del mundo. El uso de plantas medicinales en la terapia de estas enfermedades es una realidad muy extendida. Sin embargo, la mayoría de las especies vegetales contienen cristales de oxalato cálcico, producto del metabolismo vegetal y su ingesta se correlaciona con la aparición de problemas renales como la litiasis urinaria, especialmente en personas predispuestas a estas afecciones. Objetivo: Determinar la cantidad de ácido oxálico en especies vegetales que se utilizan en el tratamiento de las ECNT. Metodología: Se obtuvieron extractos acuosos y ácidos de 0,5 g del fármaco vegetal de la especie y, posteriormente, se tituló con una solución estandarizada de permanganato de potasio 0,02 mol.L-1con las concentraciones de ácido oxálico expresadas en g/100g de fármaco vegetal seco. Resultados: La concentración de ácido oxálico osciló entre 4,58 ± 0,09 g/100 g a 17,21 ± 0,07 g/100 g en especies de plantas y la extracción de ácido fue más eficiente. Se realizó una optimización metodológica para las especies que presentaron los mejores resultados, Psidiumguajava y Artocarpus heterophyllus. Conclusión: Los datos obtenidos pueden servir de base para decisiones médicas y para profesionales que prescriben plantas medicinales.

SUMMARY Introduction: Chronic non-communicable diseases (CNCDs) are a group of diseases characterized by having the highest mortality and morbidity rates in the world. Despite the increase in new drug technologies, the use of medicinal plants as an aid in therapy for these diseases is a widespread reality. However, most plant species contain inorganic crystals of calcium oxalate, a product of plant metabolism, which has several functions in plant tissues. For the human species, its ingestion is associated with the arising of kidney problems such as urinary lithiasis, especially in people who have a predisposition to these conditions. Aim: To determine the amount of oxalic acid in plant species, which are used in the treatment of CNCDs. Methodology: After collection and characterization the plant species, aqueous and acidic extracts were obtained from 0.5 g of the plant drug of each species and, subsequently, were titrated with a standardized 0.02 mol.L-1 potassium permanganate solution and the concentrations of oxalic acid were expressed in g/100 g of dry vegetable drug. Result: The data obtained from the concentration of oxalic acid ranged from 4.58 ± 0.09 g/100 g to 17.21 ± 0.07 g/100 g and demonstrated that the concentrations from acid extraction are higher compared to the aqueous extraction, for all vegetables species analyzed. Methodological optimization was performed for the species that showed the highest results, Psidium guajava and Artocarpus hetero phyllus. Conclusion: The data obtained can serve as input for medical decisions and for professionals who prescribe medicinal plants.

RESUMO Introdução: As doenças crônicas não transmissíveis (DCNT) são um grupo de doenças caracterizadas por apresentar as maiores taxas de mortalidade e morbidade do mundo. Apesar do aumento de novas tecnologias medicamentosas, o uso de plantas medicinais como auxiliar na terapia dessas doenças é uma realidade bastante difundida. No entanto, a maioria das espécies vegetais contém cristais inorgânicos de oxalato de cálcio, um produto do metabolismo vegetal, que possui diversas funções nos tecidos vegetais. Para a espécie humana, sua ingestão está associada ao surgimento de problemas renais como a litíase urinária, principalmente em pessoas com predisposição a essas condições. Objetivo: Determinar a quantidade de ácido oxálico em espécies vegetais, que são utilizadas no tratamento de DCNT. Metodologia: Após a coleta e caracterização das espécies vegetais, extratos aquosos e ácidos foram obtidos a partir de 0,5 g da droga vegetal de cada espécie e, posteriormente, titulados com solução padronizada de permanganato de potássio 0,02 mol.L-1 e as concentrações de ácido oxálico foram expressos em g/100 g de fármaco vegetal seco. Resultado: Os dados obtidos da concentração de ácido oxálico variaram de 4,58 ± 0,09 g/100 g a 17,21 ± 0,07 g/100 g e demonstraram que as concentrações da extração ácida são maiores em relação à extração aquosa, para todas as espécies vegetais analisadas. A otimização metodológica foi realizada para as espécies que apresentaram os maiores resultados, Psidiumguajava e Artocarpus heterophyllus. Conclusão: Os dados obtidos podem servir de subsídio para decisões médicas e para profissionais que prescrevem plantas medicinais.

Primary meningococcal septic arthritis associated with joint calcium oxalate crystals: A case report and review of the literature.

Primary meningococcal septic arthritis (PMSA) is an extremely rare local infection by Neisseria meningitidis in the absence of meningitis or meningococcaemia syndrome. A 30-year-old healthy, immunocompetent man presented with arthralgia, fever, chest rash, and significant swelling of the right knee. On admission, a disseminated maculopapular and purpuric rash, oligoarthritis, neutrophilia, and elevated acute phase reactants were documented. Following arthrocentesis of the right knee, isolation of N. meningitidis and the presence of calcium oxalate crystals in the synovial fluid were reported. The diagnosis of PMSA was made. Histological analysis of the skin lesion showed leucocytoclastic vasculitis. He was treated with intravenous ceftriaxone plus open surgical drainage and ambulatory cefixime with adequate response. After 1 month, he presented resolution of the pathological process. We performed an extensive review of the literature, finding that the key elements supporting the diagnosis of PMSA are prodromal upper respiratory tract symptoms and skin involvement prior to or synchronous with the arthritis. Also, the most frequently involved joint is the knee. This report is the first case of a patient presenting with PMSA associated with calcium oxalate crystals in the synovial fluid. Herein, we discuss the most frequent clinical manifestations, the unusual histological features, the recommended treatment, and the reported prognosis of this rare entity.

Colleters, Extrafloral Nectaries, and Resin Glands Protect Buds and Young Leaves of Ouratea castaneifolia (DC.) Engl. (Ochnaceae).

Buds usually possess mechanical or chemical protection and may also have secretory structures. We discovered an intricate secretory system in Ouratea castaneifolia (Ochnaceae) related to the protection of buds and young leaves. We studied this system, focusing on the distribution, morphology, histochemistry, and ultrastructure of glands during sprouting. Samples of buds and leaves were processed following the usual procedures for light and electron microscopy. Overlapping bud scales protect dormant buds, and each young leaf is covered with a pair of stipules. Stipules and scales possess a resin gland, while the former also possess an extrafloral nectary. Despite their distinct secretions, these glands are similar and comprise secreting palisade epidermis. Young leaves also possess marginal colleters. All the studied glands shared some structural traits, including palisade secretory epidermis and the absence of stomata. Secretory activity is carried out by epidermal cells. Functionally, the activity of these glands is synchronous with the young and vulnerable stage of vegetative organs. This is the first report of colleters and resin glands for O. castaneifolia. We found evidence that these glands are correlated with protection against herbivores and/or abiotic agents during a developmental stage that precedes the establishment of mechanical defenses.

Análisis de la composición química de litiasis urinaria de 649 pacientes mediante espectroscopía infrarroja, primera experiencia nacional / Chemical composition analysis of 649 urinary stones

Background: Chemical composition analysis of urinary stones is a fundamental part of the metabolic workup of urolithiasis. Aim: To report the chemical composition of urinary stones using infrared spectroscopy. Material and Methods: The chemical composition of rinary stones recovered from 649 patients aged 1 to 97 years (68% males), were analyzed using a Perkin Elmer FTIR Spectrometer, Spectrum Two. Results: Calcium oxalate monohydrate was the most common composition found in 45% of cases, followed by mixed composition, which included three ammonium phosphate stones in 29% of cases. Pure uric acid composition was found in 16% of stones. Three cystine stones were detected. Conclusions: These findings do not differ from those found in developed countries.

Do calcium oxalate crystals protect against herbivory?

Calcium oxalate (CaOx) crystals have challenged human curiosity since the advent of microscopy. These crystals are linked to the control of calcium levels in plant cells, but they have also been attributed several other functions, including protection against herbivory. However, the protection offered by CaOx crystals against herbivory may be overstated, as claims have been mainly based on their shapes and hard and indigestible nature rather than on experimental evidence. I contend that it is improbable that a constitutive defense, present since very early in the evolution of plants, has not been superseded by herbivores, especially insects. Here, I present arguments and evidence that suggest that these crystals have low efficiency in protecting plants against herbivores. First, I argue that insects with chewing mouthparts possess a semipermeable structure that protects their midgut, minimizing damage from crystals. Second, the action of CaOx crystals is purely mechanical and similar to other inert materials such as sand. Therefore, CaOx crystals only provide effective protection from herbivory in very particular cases and should not be considered an effective defense without supporting experimental evidence.

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid).

In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 °C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquid-precursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20-400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.

Oligochitosan Synthesized by Cunninghamella elegans, a Fungus from Caatinga (The Brazilian Savanna) Is a Better Antioxidant than Animal Chitosan.

Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress.

Bilateral ureterolithiasis in a 7-month-old cat / Ureterolitíase bilateral em um gato de sete meses de idade

ABSTRACT: Feline ureteral obstruction can have several causes; however, ureterolithiasis has been increasing in occurrence. The restriction of urinary flow induced by the obstruction has harmful consequences to the body and can lead to acute renal failure. Calcium oxalate ureterolithiasis is reported in older cats, aged mean 12 years old. A case of bilateral ureteral obstruction in a 7-month-old mixed breed cat is described in this report. Imaging tests such as abdominal ultrasonography, radiography and excretory urography were performed to determine the diagnosis. The surgical procedure of bilateral ureterotomy was then performed, which allowed the improvement of the urinary flow of both kidneys and the resolution of clinical signs caused by uremia. The quantitative analysis of both uroliths revealed the composition of 100% monohydrate calcium oxalate. Calcium oxalate stones can also cause ureteral obstruction in young cats; although, are less common in this age. When conservative treatment fails, surgical intervention becomes necessary for the rapid return of renal function. To author's knowledge this is the first report of a ureterolithiasis caused by calcium oxalate in a young cat.

RESUMO: A obstrução ureteral em gatos pode ter diversas causas, entretanto, a ureterolitíase vem apresentando um aumento na sua ocorrência. A restrição do fluxo urinário induzida pela obstrução traz consequências graves ao organismo, podendo levar a insuficiência renal aguda. A ureterolitíase por cálculos de oxalato de cálcio é relatada em gatos mais velhos, com média de idade de 12 anos. Um caso de obstrução ureteral bilateral em um gato, SRD, com sete meses de idade é descrito nesse relato. Exames de imagem, como ultrassonografia e radiografia abdominais e urografia excretora, foram realizados para confirmar o diagnóstico. O procedimento cirúrgico de ureterotomia bilateral foi então realizado, permitindo a melhora do fluxo urinário de ambos os rins e dos sinais clínicos de uremia. A análise quantitativa de ambos os urólitos revelou a composição de 100% oxalato de cálcio monohidratado. Cálculos de oxalato de cálcio são um diagnóstico diferencial para obstrução ureteral também em gatos jovens, apesar de serem menos comuns. Quando há falha no tratamento conservador, a intervenção cirúrgica torna-se necessária para o rápido restabelecimento e preservação da função renal. No conhecimento dos autores, esse é o primeiro relato de ureterolitíase causada por oxalato de cálcio em um gato jovem.

Nucleation and growth inhibition of biological minerals by cementum attachment protein-derived peptide (CAP-pi).

Biomineralization is a highly regulated process where proteins/peptides-crystal interactions contribute to the shaping, phasing and aggregation of minerals. We have identified and synthesized a cementum attachment protein-derived peptide (CAP-pi), which corresponds to amino acids 40-53 of the N-terminal CAP domain (MASSDEDGTNGGAS) and its phosphorylated variant (MASpSpDEDGTNGGASp) (CAP-pip). The peptide is composed of polar and negatively charged amino acids, which are disordered, according to in silico analysis. Our results show that CAP-pi inhibits hydroxyapatite (HA) formation and growth. However, it possesses low capacity to inhibit calcium oxalate crystal growth. CAP-pip showed a stronger inhibitory effect on the formation and growth of HA. As well as a high capacity to inhibit calcium oxalate monohydrate growth, mainly due to adsorption on specific growth faces. Small peptides have many advantages over the full-size protein, including low-cost production and modulation characteristics that allow for structural changes. Our findings suggest that CAP-pip-derived peptide could possess therapeutic potential to prevent or treat pathological calcifications such as renal stones and vascular calcification.

Antioxidant Sulfated Polysaccharide from Edible Red Seaweed Gracilaria birdiae is an Inhibitor of Calcium Oxalate Crystal Formation.

The genus Gracilaria synthesizes sulfated polysaccharides (SPs). Many of these SPs, including those synthesized by the edible seaweed Gracilaria birdiae, have not yet been adequately investigated for their use as potential pharmaceutical compounds. Previous studies have demonstrated the immunomodulatory effects of sulfated galactans from G. birdiae. In this study, a galactan (GB) was extracted from G. birdiae and evaluated by cell proliferation and antioxidant tests. GB showed no radical hydroxyl (OH) and superoxide (O2-) scavenging ability. However, GB was able to donate electrons in two further different assays and presented iron- and copper-chelating activity. Urolithiasis affects approximately 10% of the world's population and is strongly associated with calcium oxalate (CaOx) crystals. No efficient compound is currently available for the treatment of this disease. GB appeared to interact with and stabilize calcium oxalate dihydrate crystals, leading to the modification of their morphology, size, and surface charge. These crystals then acquired the same characteristics as those found in healthy individuals. In addition, GB showed no cytotoxic effect against human kidney cells (HEK-293). Taken together, our current findings highlight the potential application of GB as an antiurolithic agent.

Persistent Calyxes in Postbloom Fruit Drop: A Microscopy and Microanalysis Perspective.

Citrus postbloom fruit drop, caused by Colletotrichum spp., is an important disease in the Americas. The pathogen infects citrus flowers, produces orange-brown lesions on petals, and may cause the abscission of young fruit. In diseased flowers, the calyxes remain attached to the peduncle after the young fruit drop. No anatomical and microanalysis studies have been conducted to determine whether calyx tissues can be infected by Colletotrichum spp. and why calyxes remain attached to the peduncle. Based on light microscopy, we demonstrate that the ovary abscission zone exhibits a separation region composed of layers of thickened lignified walled cells, indicating that abscission involves the disruption of cell walls. The first layers of the protective zone (PZ) are composed of densely packed cells with suberized walls produced by the wound meristem. Beneath the PZ, there is a compact mass of small cells that accumulate starch grains. X-ray fluorescence microanalysis (µ-XRF) confirmed the increased accumulation of calcium in the receptacle of the persistent calyxes compared to non-inoculated citrus flowers. Moreover, the peduncle pith and the receptacle exhibit hypertrophied cells with thick walls that may be related to calyx retention. Fungal structures are not observed inside the persistent calyx tissues.

Acute Kidney Injury with Neurological Features: Beware of the Star Fruit and its Caramboxin.

Star fruit (Averrhoa carambola) is a well-known product in tropical countries. There are few reports published in literature with acute kidney injury due to oxalate induced nephropathy. However, none of them have an important neurological feature. We present a case of a 51-year-old male with paresis and altered mental status. Screening for neurological diseases such as stroke, Guillain-Barre, meningitis and encephalitis were negative. In the evolution, he developed acute kidney failure and was submitted to 4 dialysis sessions. After talking to the family, we discovered he had ingested over 50 star fruits prior to the acute neurologic deficits. He recovered renal function so a renal biopsy was not required. Physicians should actively look for star fruit ingestion history in patients presenting with unexplained acute kidney injury with or without neurological features. Besides, taking star fruit in a large amount, accompanied by an empty stomach and dehydrated state, is a risk factor for neurotoxicity.