The inducing effect of potassium citrate （K3cit） on simultaneous growth of calcium oxalate mono-（COM）, di-（COD）, and trihydrate （COT） crystals in synthetic urine was observed with double diffusion gelatinous t...The inducing effect of potassium citrate （K3cit） on simultaneous growth of calcium oxalate mono-（COM）, di-（COD）, and trihydrate （COT） crystals in synthetic urine was observed with double diffusion gelatinous technique. K3cit can induce the formation of COD and COT, inhibit the aggregation and decrease the surface area of COM crystals. It supported the clinical use of K3cit and may provide important clues to this disease in cure and in search for new drugs.展开更多
The effects of temperature and multifunctional sodium carboxylate additives on the phase composition and morphology of calcium oxalate (CaOxa) crystals grown in silica gel system were systematically investigated using...The effects of temperature and multifunctional sodium carboxylate additives on the phase composition and morphology of calcium oxalate (CaOxa) crystals grown in silica gel system were systematically investigated using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and Fourier-transform infrared spectra (FT-IR). The sodium carboxylates investigated include: monocarboxylate sodium acetate (NaAc), disodium tartrate (Na2tart), trisodium citrate (Na3cit), and the disodium salt of ethylenediaminetetraacetic acid (Na2edta). The temperature range was from 7°C to 67°C. The crystallization temperature affects the phase compositions, the growth rate, and the morphology of CaOxa. First, the logarithm of the percentage of calcium oxalate dihydrate (COD) formed at a certain temperature (T) is proportional to the reciprocal of temperature (1/T). Second, the weight of CaOxa crystals decreases as decreasing the temperature. At a given temperature, the ability of the sodium carboxylates to induce COD follows the order: Na2edta Na3cit Na2tart NaAc. Third, the multicarboxylates can decrease the surface area of calcium oxalate monohydrate (COM). It makes the edges and tips of COM crystals blunt and oval. All the three changes, an increase of the content of COD, a decrease of the weight of CaOxa crystals, and a decrease of the surface area of COM crystals, can inhibit the formation of CaOxa stones. These results support the clinical use of citrates and may be helpful in elucidating the mechanisms of the formation of CaOxa calculus. Keywords calcium oxalate - sodium carboxylate - gel - urinary calculi - crystallization - biomineralization展开更多
The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid （H4edta）, citric acid （H3cit）, tartaric acid （H2tart）, and acetic acid （HOAc） on growth and aggr...The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid （H4edta）, citric acid （H3cit）, tartaric acid （H2tart）, and acetic acid （HOAc） on growth and aggregation of calcium oxalate （CaOxa） in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of cal- cium oxalate monohydrate （COM） and induce the formation of calcium oxalate dihydrate （COD）. H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order： H4edta〉H3cit〉H2tart〉 〉HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.展开更多
The purpose of this work was to detect the properties of African green monkey renal epithelial cells （Vero） after oxidative injury and to study the mediation of the injured Vero on aggregation and formation of calci...The purpose of this work was to detect the properties of African green monkey renal epithelial cells （Vero） after oxidative injury and to study the mediation of the injured Vero on aggregation and formation of calcium oxalate crystals. This injury model was induced by 0.15 mmol/L H2O2 according to the pretest evaluation. The results suggested that H2O2 could injure Vero significantly and decrease cell viability in a time-dependent manner for exposure time of 0.5--2 h. After cell injury, the indexes connected with oxidative injury changed. The malondialdehyde （MDA） content and osteopontin （OPN） expression increased, while superoxide dismutase （SOD） level decreased. It resulted in the increase of both the amount of CaOxa crystals and the degree of crystal aggregation on the injured cells. This work indicated that injured cells promoted the formation of calcium oxalate monohydrate （COM） crystals, thus increased the risk of formation of urinary stone.展开更多
Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees. The biological roles for calcium oxalate crysta...Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees. The biological roles for calcium oxalate crystal formation in plant growth and development include high-capacity calcium regulation, protection against herbivory, and tolerance to heavy metals. Using a variety of experimental approaches researchers have begun to unravel the complex mechanisms controlling formation of this biomineral. Given the important roles for calcium oxalate formation in plant survival and the antinutrient and pathological impact on human health through its presence in plant foods, researchers are avidly seeking a more comprehensive understanding of how these crystals form. Such an understanding will be useful in efforts to design strategies aimed at improving the nutritional quality and production of plant foods.展开更多
Crystallization of calcium oxalate is studied mainly in the diluted healthy urine using scanning electron microscopy (SEM), and is compared with the crystallization in the diluted pathological urine. It suggests that ...Crystallization of calcium oxalate is studied mainly in the diluted healthy urine using scanning electron microscopy (SEM), and is compared with the crystallization in the diluted pathological urine. It suggests that the average sizes of calcium oxalate crystals are not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Only in the concentration range of 0.60-0.90 mmol/L can larger size of CaOx crystals appear. When the concentrations of Ca2+ and Ox2- ions are 1.20, 0.80, 0.60, 0.30 and 0.15 mmol/L in the healthy urine, the average sizes of calcium oxalate crystallites are 9.5 X 6.5, 20.0 X 13.5 and 15.0 jj,m X 10.0 jj,m, respectively, for the former three samples after 6 d crystallization. No crystal appears even after 30 d crystallization for the samples of concentrations of 0.30 and 0.15 mmol/L due to their low supersaturations. The results theoretically explain why the probability of stone forming is clinically not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Laser scattering technology also confirms this point. The reason why healthy human has no risk of urinary stone but stone-formers have is that there are more urinary macromolecules in healthy human urines than that in stone-forming urines. These macromolecules may control the transformation in CaOx crystal structure from monohydrate cal-cium oxalate (COM) to dihydrate calcium oxalate (COD). COD has a weaker affinity for renal tubule cell membranes than COM. No remarkable effect of the crystallization time is observed on the crystal morphology of CaOx. All the crystals are obtuse hexagon. However, the sizes and the number of CaOx crystals can be affected by the crystallization time. In the early stage of crystalli-zation (1-6 d), the sizes of CaOx crystals increase and the number of crystal particles changes little as increasing the crystallization time due to growth control. In the middle and late stages (6-30 d), the number of crystals increases markedly while the growth rate changes little due to the nucleation control.展开更多
The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective ...The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.展开更多
The nucleation, growth and aggregation of calcium oxalate(CaC 2O 4) crystals were comparatively investigated in five different mimetic systems: water, NaCl solution, artificial urine, healthy urine and lithogenic urin...The nucleation, growth and aggregation of calcium oxalate(CaC 2O 4) crystals were comparatively investigated in five different mimetic systems: water, NaCl solution, artificial urine, healthy urine and lithogenic urine by using scanning electron microscopy(SEM). The effects of original concentration of calcium ion and oxalate ion and crystallization time on the morphology, density and the size of CaC 2O 4 crystals were discussed. In lithogenic urine, calcium oxalate monohydrate(COM) crystals were the dominant phase. However, a mixture of COM and calcium oxalate dihydrate(COD) with a molar ratio of about 3∶2 was obtained in the healthy urine. COD has a less affinity for renal tubule cell surface, so COD is easy to be expelled out from body and there is a less probability of stone-forming in the healthy urine. The fastest nucleation and growth of CaC 2O 4 crystals were obtained in water and NaCl solution, respectively. The size of CaC 2O 4 crystals decreases in the following order: NaCl solution>artificial urine>lithogenic urine>healthy urine>water.展开更多
The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DP...The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.展开更多
基金This research work was granted by the National Natural Science Foundation of China （No 20471024）.
文摘The inducing effect of potassium citrate （K3cit） on simultaneous growth of calcium oxalate mono-（COM）, di-（COD）, and trihydrate （COT） crystals in synthetic urine was observed with double diffusion gelatinous technique. K3cit can induce the formation of COD and COT, inhibit the aggregation and decrease the surface area of COM crystals. It supported the clinical use of K3cit and may provide important clues to this disease in cure and in search for new drugs.
基金This research work was supported by the National Natural Science Foundation of China(Grant No.20031010)the Key Project of Natural Science Foundation of Guangdong Province(Grant No.013202)+1 种基金the Key Project of Guangdong Province(Grant No.C31401)a Fellowship of Alexander yon Humboldt-Stiftung of Germany.
文摘The effects of temperature and multifunctional sodium carboxylate additives on the phase composition and morphology of calcium oxalate (CaOxa) crystals grown in silica gel system were systematically investigated using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and Fourier-transform infrared spectra (FT-IR). The sodium carboxylates investigated include: monocarboxylate sodium acetate (NaAc), disodium tartrate (Na2tart), trisodium citrate (Na3cit), and the disodium salt of ethylenediaminetetraacetic acid (Na2edta). The temperature range was from 7°C to 67°C. The crystallization temperature affects the phase compositions, the growth rate, and the morphology of CaOxa. First, the logarithm of the percentage of calcium oxalate dihydrate (COD) formed at a certain temperature (T) is proportional to the reciprocal of temperature (1/T). Second, the weight of CaOxa crystals decreases as decreasing the temperature. At a given temperature, the ability of the sodium carboxylates to induce COD follows the order: Na2edta Na3cit Na2tart NaAc. Third, the multicarboxylates can decrease the surface area of calcium oxalate monohydrate (COM). It makes the edges and tips of COM crystals blunt and oval. All the three changes, an increase of the content of COD, a decrease of the weight of CaOxa crystals, and a decrease of the surface area of COM crystals, can inhibit the formation of CaOxa stones. These results support the clinical use of citrates and may be helpful in elucidating the mechanisms of the formation of CaOxa calculus. Keywords calcium oxalate - sodium carboxylate - gel - urinary calculi - crystallization - biomineralization
基金Project supported by the National Natural Science Foundation of China （Nos. 30672103, 20471024） and the Key Project of Guangdong Province （Nos. 2005B30701003, 2006B36501001）.
文摘The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid （H4edta）, citric acid （H3cit）, tartaric acid （H2tart）, and acetic acid （HOAc） on growth and aggregation of calcium oxalate （CaOxa） in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of cal- cium oxalate monohydrate （COM） and induce the formation of calcium oxalate dihydrate （COD）. H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order： H4edta〉H3cit〉H2tart〉 〉HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.
文摘The purpose of this work was to detect the properties of African green monkey renal epithelial cells （Vero） after oxidative injury and to study the mediation of the injured Vero on aggregation and formation of calcium oxalate crystals. This injury model was induced by 0.15 mmol/L H2O2 according to the pretest evaluation. The results suggested that H2O2 could injure Vero significantly and decrease cell viability in a time-dependent manner for exposure time of 0.5--2 h. After cell injury, the indexes connected with oxidative injury changed. The malondialdehyde （MDA） content and osteopontin （OPN） expression increased, while superoxide dismutase （SOD） level decreased. It resulted in the increase of both the amount of CaOxa crystals and the degree of crystal aggregation on the injured cells. This work indicated that injured cells promoted the formation of calcium oxalate monohydrate （COM） crystals, thus increased the risk of formation of urinary stone.
文摘Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees. The biological roles for calcium oxalate crystal formation in plant growth and development include high-capacity calcium regulation, protection against herbivory, and tolerance to heavy metals. Using a variety of experimental approaches researchers have begun to unravel the complex mechanisms controlling formation of this biomineral. Given the important roles for calcium oxalate formation in plant survival and the antinutrient and pathological impact on human health through its presence in plant foods, researchers are avidly seeking a more comprehensive understanding of how these crystals form. Such an understanding will be useful in efforts to design strategies aimed at improving the nutritional quality and production of plant foods.
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.20031010)the Key Project of Science and Technology of Guangzhou(Grant No.SZ-613)+2 种基金the Natural Science Foundation of Guangdong Province(Grant Nos.013202 and 980898)the Key Project of Guangdong Province(Grant No.C31401)the Key Project of Science and Technology of the Ministry of Education,China(Grant No.1998-121).
文摘Crystallization of calcium oxalate is studied mainly in the diluted healthy urine using scanning electron microscopy (SEM), and is compared with the crystallization in the diluted pathological urine. It suggests that the average sizes of calcium oxalate crystals are not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Only in the concentration range of 0.60-0.90 mmol/L can larger size of CaOx crystals appear. When the concentrations of Ca2+ and Ox2- ions are 1.20, 0.80, 0.60, 0.30 and 0.15 mmol/L in the healthy urine, the average sizes of calcium oxalate crystallites are 9.5 X 6.5, 20.0 X 13.5 and 15.0 jj,m X 10.0 jj,m, respectively, for the former three samples after 6 d crystallization. No crystal appears even after 30 d crystallization for the samples of concentrations of 0.30 and 0.15 mmol/L due to their low supersaturations. The results theoretically explain why the probability of stone forming is clinically not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Laser scattering technology also confirms this point. The reason why healthy human has no risk of urinary stone but stone-formers have is that there are more urinary macromolecules in healthy human urines than that in stone-forming urines. These macromolecules may control the transformation in CaOx crystal structure from monohydrate cal-cium oxalate (COM) to dihydrate calcium oxalate (COD). COD has a weaker affinity for renal tubule cell membranes than COM. No remarkable effect of the crystallization time is observed on the crystal morphology of CaOx. All the crystals are obtuse hexagon. However, the sizes and the number of CaOx crystals can be affected by the crystallization time. In the early stage of crystalli-zation (1-6 d), the sizes of CaOx crystals increase and the number of crystal particles changes little as increasing the crystallization time due to growth control. In the middle and late stages (6-30 d), the number of crystals increases markedly while the growth rate changes little due to the nucleation control.
基金Supported by the National Natural Science Foundation of China (Grant No.20471024)
文摘The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.
文摘The nucleation, growth and aggregation of calcium oxalate(CaC 2O 4) crystals were comparatively investigated in five different mimetic systems: water, NaCl solution, artificial urine, healthy urine and lithogenic urine by using scanning electron microscopy(SEM). The effects of original concentration of calcium ion and oxalate ion and crystallization time on the morphology, density and the size of CaC 2O 4 crystals were discussed. In lithogenic urine, calcium oxalate monohydrate(COM) crystals were the dominant phase. However, a mixture of COM and calcium oxalate dihydrate(COD) with a molar ratio of about 3∶2 was obtained in the healthy urine. COD has a less affinity for renal tubule cell surface, so COD is easy to be expelled out from body and there is a less probability of stone-forming in the healthy urine. The fastest nucleation and growth of CaC 2O 4 crystals were obtained in water and NaCl solution, respectively. The size of CaC 2O 4 crystals decreases in the following order: NaCl solution>artificial urine>lithogenic urine>healthy urine>water.
文摘The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.
