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1.
As caries is a most common affliction of teeth, which are predominantly composed of inorganic elements, it was considered worthwhile to determine their elemental composition and to find if it bears any relation to caries formation. For this purpose, 35 inorganic elements were determined in 15 non-carious and an equal number of carious whole teeth after their dissolution in nitric acid. The results showed that out of 35 elements, strontium was the only element found to be present in significantly lower amount in carious teeth, thus strongly suggesting that its deficiency may help form caries. The decrease in Ca, Mg, Ti, P, Li, Be, V, Ni, Zn, Nb, Ag, Cd, Sb, Ba, La , W, Pb, and Bi and slight increase in K, Cr, Cu, and As was not statistically significant. However, statistically significantly greater amount of boron, manganese, molybdenum, and fluorine in the carious teeth indicates towards their possible role in predisposing or causing dental caries. 相似文献
2.
The aim of the present study was to develop and evaluate a buccal adhesive tablet containing ondansetron hydrochloride (OH).
Special punches and dies were fabricated and used while preparing buccal adhesive tablets. The tablets were prepared using
carbopol (CP 934), sodium alginate, sodium carboxymethylcellulose low viscosity (SCMC LV), and hydroxypropylmethylcellulose
(HPMC 15cps) as mucoadhsive polymers to impart mucoadhesion and ethyl cellulose to act as an impermeable backing layer. The
formulations were prepared by direct compression and characterized by different parameters such as weight uniformity, content
uniformity, thickness, hardness, swelling index, in vitro drug release studies, mucoadhesive strength, and ex vivo permeation study. As compared with the optimized formulation composed of OH—5 mg, CP 934—30 mg, SCMC LV—165 mg, PEG 6000—40 mg,
lactose—5 mg, magnesium stearate—1.5 mg, and aspartame—2 mg, which gave the maximum release (88.15%), non-bitter (OH) that
form namely ondansetron base and complexed ondansetron was used in order to make the selected formulation acceptable to human.
The result of the in vitro release studies and permeation studies through bovine buccal mucosa revealed that complexed ondansetron gave the maximum
release and permeation. The stability of drug in the optimized adhesive tablet was tested for 6 h in natural human saliva;
both the drug and device were found to be stable in natural human saliva. Thus, buccal adhesive tablet of ondansetron could
be an alternative route to bypass the hepatic first-pass metabolism and to improve the bioavailability of (OH). 相似文献
3.
Benjamin Kruppke Christiane Heinemann Alena-Svenja Wagner Jana Farack Sabine Wenisch Hans-Peter Wiesmann Thomas Hanke 《Development, growth & differentiation》2019,61(2):166-175
In order to investigate the influence of calcium and strontium ion concentration on human bone marrow stromal cells and their differentiation to osteoblasts, different cell culture media have been used. Even though this study does not contain a bone substitute material, the reason for this study was the decrease of cation concentration by many biomaterials, due to induced apatite precipitation. As a consequence, the reduced calcium ion concentration is known to affect osteoblastic development. Therefore, the main focus was put on the question, whether an increased strontium concentration (in the range of mM) might be suitable to compensate the lack of calcium ions. The effect of solely strontium ions—with only calcium in the media resulting from fetal calf serum—was investigated. Commercially available calcium-free medium (modified α-MEM) was tested in comparison with media with varied calcium ion concentrations (0.9, 1.8, and 3.6 mM), or strontium ion concentration (0.4, 0.9, 1.8, and 3.6 mM). In case of calcium, higher concentrations cause increased proliferation, while differentiation was shifted to earlier points of time. Differentiation was increased by solely strontium ions only at 0.4–0.9 mM, while proliferation was highest for 0.9–1.8 mM. From these results, it can be concluded that strontium is able to compensate a lack of calcium to a certain degree. Thus, in contrast to calcium ion release, a strontium ion release from bone substitute materials might be applicable for stimulation of bone regeneration without influencing the media saturation. 相似文献
4.
Jelena Kosoric Ralph Anthony D. Williams Mark P. Hector Paul Anderson 《International journal of peptide research and therapeutics》2007,13(4):497-503
The salivary protein statherin is an inhibitor of spontaneous and secondary precipitation of hydroxyapatite (HAp). It is also
detected in enamel pellicle. The N-terminal region of statherin is involved in its adsorption onto tooth surfaces, and, calcium
binding. A peptide (StN21) was designed with a 21 amino acid sequence identical to the N-terminus of statherin. The aim was
to measure the effect of StN21 on the rate of mineral loss in a model system for dental caries and erosion using HAp subjected
to artificial carious and erosive conditions. StN21 was synthesised using Fmoc chemistry. A surface of each HAp block was
exposed to solution containing StN21 at concentrations 9.4–376 μmol L−1 (in phosphate buffer) for 24 h. Controls were HAp exposed to buffer only, and HAp exposed to lysozyme. Demineralising solution
(0.1 mol L−1 acetic acid, pH 4.5, 1.0 mmol L−1 calcium and 0.6 mmol L−1 phosphate) was circulated past the HAp blocks at 0.4 mL min-1 to mimic carious and erosive conditions. Scanning microradiography was used to measure the rate of mineral loss for demineralisation
periods of 3 weeks. The rate of mineral loss of the samples exposed to StN21 was reduced by ∼40% compared to the controls,
but no dependence on the concentration of StN21 was observed at the concentrations used. StN21 has been shown to be a potent
and stable peptide that has potential as a preventive/therapeutic agent in the treatment of enamel erosion and dental caries. 相似文献
5.
Elias Burguera Ziary Romero Marcela Burguera José Luis Burguera Hella de Arenas Carlos Rondon Maria Luisa di Bernado 《Journal of trace elements in medicine and biology》2002,16(2):103-112
Some cationic species (Ca, Mg, Sr, Cu, Zn and Pb) have been determined in temporary teeth (n = 67) sampled from a children population living in Mérida, Venezuela, with a mean age of 87.76 +/- 34.50 months within a range from 29 to 151 months. Each powdered tooth sample was analyzed for calcium, magnesium, strontium and zinc and for copper and lead by atomic absorption spectrometry with flame and electrothermal atomization, respectively. Relations between variables (elements concentration, age, sex, tooth type and caries status) were established using the Pearson correlation matrix and analysis of variance. The mean global concentrations were of 39.25 +/- 5.36; 1.08 +/- 0.81; 89.27 +/- 13.26 and 2.85 +/- 1.14 micrograms/g for Sr, Cu, Zn and Pb and of 208.45 +/- 33.18 and 8.51 +/- 2.05 mg/g for Ca and Mg, respectively. There were no changes in the teeth mineral content with respect to the children age and sex. With respect to the tooth type, there were significant differences only for strontium which varied in the order molars > canines > incisors. Although healthy teeth had higher mineral concentrations than carious teeth, there were not significant differences, proving that both, carious and healthy teeth could be used as indicators of mineral uptake. Magnesium and copper are the elements least related with the others. Significant positive correlations were found between Sr-Zn, Sr-Cu, Sr-Pb, and the only negative correlations were between Ca-Zn and Ca-Pb for the different types of teeth. While the positive association might indicate competition for anionic groups or similar affinity for the same sites in the crystalline structure, the negative correlations showed possible substitutions among the elements. 相似文献
6.
Yosra Shaaban R. Elnaggar Magda A. El-Massik Ossama Y. Abdallah Abd Elazim R. Ebian 《AAPS PharmSciTech》2010,11(2):645-651
The recent challenge in orally disintegrating tablets (ODT) manufacturing encompasses the compromise between instantaneous
disintegration, sufficient hardness, and standard processing equipment. The current investigation constitutes one attempt
to fulfill this challenge. Maltodextrin, in the present work, was utilized as a novel excipient to prepare ODT of meclizine.
Tablets were prepared by both direct compression and wet granulation techniques. The effect of maltodextrin concentrations
on ODT characteristics—manifested as hardness and disintegration time—was studied. The effect of conditioning (40°C and 75%
relative humidity) as a post-compression treatment on ODT characteristics was also assessed. Furthermore, maltodextrin-pronounced
hardening effect was investigated using differential scanning calorimetry (DSC) and X-ray analysis. Results revealed that
in both techniques, rapid disintegration (30–40 s) would be achieved on the cost of tablet hardness (about 1 kg). Post-compression
conditioning of tablets resulted in an increase in hardness (3 kg), while keeping rapid disintegration (30–40 s) according
to guidance of the FDA for ODT. However, direct compression-conditioning technique exhibited drawbacks of long conditioning
time and appearance of the so-called patch effect. These problems were, yet, absent in wet granulation-conditioning technique.
DSC and X-ray analysis suggested involvement of glass-elastic deformation in maltodextrin hardening effect. High-performance
liquid chromatography analysis of meclizine ODT suggested no degradation of the drug by the applied conditions of temperature
and humidity. Overall results proposed that maltodextrin is a promising saccharide for production of ODT with accepted hardness-disintegration
time compromise, utilizing standard processing equipment and phenomena of phase transition. 相似文献
7.
Roger J. Bick Michelle Mann Brian Poindexter Mya C. Schiess 《International journal of peptide research and therapeutics》2008,14(2):193-199
It was previously determined that the site of action of calcitonin gene-related peptide (CGRP) in cardiomyocytes was predominantly
at the sarcolemmal calcium release channel, and studies have shown that CGRP has major effects on intracellular cardiomyocyte
calcium concentrations. We postulated that CGRP would have similar effects on striated skeletal muscle and determined the
effects of CGRP on calcium levels in cultured chick myotubes by fluorescence imaging. Myoblasts were cultured until they were
continuous myotubes. Deconvolution fluorescence imaging was employed to visualize subcellular organelles and construct 3D
renditions. Myotubes were treated with a high (1 μM) and a low (1 nM) concentration of CGRP for 1 h or 24 h time periods,
and real-time fluorescence spectrophotometry with a calcium specific fluoroprobe permitted the acquisition of images and calcium
transients. Experiments also used CGRP 8–37 to ensure specificity of action of the full-length neuropeptide. CGRP localizations
by image stacking were made using fluorescence deconvolution microscopy and distributions on the myotubes were shown. Myotube
contractions and intracellular calcium levels were dose dependent, a high CGRP concentration producing calcium overload. CGRP
8–37 had no effect on contractions or calcium levels. Reconstructed images revealed the neuropeptide to be localized to juxta-nuclear
areas, supporting the likelihood of site specific actions. CGRP has dramatic effects on intracellular calcium in striated
muscle, high concentrations producing sustained contractions and calcium overload. The results give support to a mechanistic
role for CGRP in muscle tension headaches, and underscore the importance in the development of CGRP analogues or receptor
antagonists for treatment. 相似文献
8.
Strontium (Sr) ralenate is a new agent used for the prevention and treatment of osteoporosis. As a bone-seeking element, 98%
of Sr is deposited in the bone and teeth after oral ingestion. However, the effect of Sr treatment on bone microarchitecture
and bone nanomechanical properties remains unclear. In this study, 18 osteoporotic goats were divided into four groups according
to the treatment regimen: control, calcium alone (Ca), calcium and Sr at 24 mg/kg (Ca + 24Sr), and calcium and Sr at 40 mg/kg
(Ca + 40Sr). The effects of Sr administration on bone microarchitecture and nanomechanical properties of trabecular bones
were analyzed with micro-CT and nanoindentation test, respectively. Serum Sr levels increased six- and tenfold in the Ca + 24Sr
and Ca + 40Sr groups, respectively. Similarly, Sr in the bone increased four- and sixfold in these two groups. Sr administration
significantly increased trabecular bone volume fraction, trabecular thickness, and double-labeled new bone area. Sr administration,
however, did not significantly change the nanomechanical properties of trabecular bone (elastic modulus and hardness). The
data suggested that Sr administration increased trabecular bone volume and improved the microarchitecture while maintaining
the intrinsic tissue properties in the osteoporotic goat model. 相似文献
9.
The purpose of the present study was to investigate the potential use of two PEGylated derivatives of rosin (PD) as sustained
release film forming materials. The derivatives differed chemically by their acid numbers—PD-1 with 120.93 and PD-2 with 88.19.
The derivative films were characterized for surface morphology, water uptake-weight loss, angle of contact, water vapor transmission
rate, mechanical properties and permeability study. Dissolution of diclofenac sodium (DS) and propranolol hydrochloride (PHL)
as model drugs was studied from coated pellets. The films of derivatives with and without plasticizers were smooth and continuous.
PD-2 films developed greater numbers of pores when in contact with phosphate buffer pH 6.8. The low weight loss, low angles
of contact and high water vapor transmission rate of PD-2 films were related to presence of higher concentration of PEG esters.
Higher tensile strength and percent elongation of PD-2 films was due to greater degree of internal plasticization of the derivative.
The permeability of films to model drugs propranolol hydrochloride and diclofenac sodium was inversely proportional to the
film thickness and dibutyl phthalate concentration in them; the permeability being greatest in PD-2 films containing 10% PEG
200. Dissolution rate of propranolol hydrochloride was higher from the coated pellets. The dissolution data followed zero
order, Baker–Lonsdale equation and Hixon–Crowell equation of release kinetics with high correlation coefficients. The mechanism
of drug release from these coated systems however followed class II transport (n > 1.0). The derivatives investigated could successfully retard release of the model drugs and offers an alternative to the
conventionally used polymers. 相似文献
10.
Ian Towle Joel D. Irish Kris H. Sabbi Carolina Loch 《American journal of primatology》2022,84(1):e23349
Dental caries has been reported in a variety of primates, although it is still considered rare in wild populations. In this study, 11 catarrhine primate taxa (n = 339 individuals; 7946 teeth) were studied for the presence of caries. A differential diagnosis of lesions in interproximal regions of anterior teeth was undertaken, since they had been previously described as both carious and non-carious in origin. Each permanent tooth was examined macroscopically, with severity and position of lesions recorded. Two specimens were examined further, using micro-CT scans to assess demineralization. Differential diagnosis confirmed the cariogenic nature of interproximal cavities on anterior teeth (ICATs). Overall results show 3.3% of all teeth (i.e., anterior and posterior teeth combined) were carious (n = 262), with prevalence varying among species from 0% to >7% of teeth affected. Those with the highest prevalence of ICATs include Pan troglodytes verus (9.8% of anterior teeth), Gorilla gorilla gorilla (2.6%), Cercopithecus denti (22.4%), Presbytis femoralis (19.5%), and Cercopithecus mitis (18.3%). ICATs make up 87.9% of carious lesions on anterior teeth. These results likely reflect dietary and food processing differences among species, but also between the sexes (e.g., 9.3% of all female P. troglodytes verus teeth were carious vs. 1.8% in males). Processing cariogenic fruits and seeds with the anterior dentition (e.g., wadging) likely contributes to ICAT formation. Further research is needed in living primate populations to ascertain behavioral/dietary influences on caries occurrence. Given the presence of ICATs in frugivorous primates, their diagnosis in archaeological and paleontological specimens may shed light on diet and food processing behaviors in fossil primates. 相似文献
11.
GLOBIO3: A Framework to Investigate Options for Reducing Global Terrestrial Biodiversity Loss 总被引:3,自引:0,他引:3
Rob Alkemade Mark van Oorschot Lera Miles Christian Nellemann Michel Bakkenes Ben ten Brink 《Ecosystems》2009,12(3):374-390
The GLOBIO3 model has been developed to assess human-induced changes in biodiversity, in the past, present, and future at
regional and global scales. The model is built on simple cause–effect relationships between environmental drivers and biodiversity
impacts, based on state-of-the-art knowledge. The mean abundance of original species relative to their abundance in undisturbed
ecosystems (MSA) is used as the indicator for biodiversity. Changes in drivers are derived from the IMAGE 2.4 model. Drivers
considered are land-cover change, land-use intensity, fragmentation, climate change, atmospheric nitrogen deposition, and
infrastructure development. GLOBIO3 addresses (i) the impacts of environmental drivers on MSA and their relative importance;
(ii) expected trends under various future scenarios; and (iii) the likely effects of various policy response options. GLOBIO3
has been used successfully in several integrated regional and global assessments. Three different global-scale policy options
have been evaluated on their potential to reduce MSA loss. These options are: climate-change mitigation through expanded use
of bio-energy, an increase in plantation forestry, and an increase in protected areas. We conclude that MSA loss is likely
to continue during the coming decades. Plantation forestry may help to reduce the rate of loss, whereas climate-change mitigation
through the extensive use of bioenergy crops will, in fact, increase this rate of loss. The protection of 20% of all large
ecosystems leads to a small reduction in the rate of loss, provided that protection is effective and that currently degraded
protected areas are restored.
Author Contributions RA—Writing, study design, data analyses; MvO—Writing, research; LM— Writing, data analyses; CN—Contribution to method; MB—Research,
data analyses; BtB—Contribution to method. 相似文献
12.
Oliva-Rodríguez R Pérez-Urizar J Dibildox-Alvarado E Martínez-Saldaña MC Avelar-González FJ Flores-Reyes H Pozos-Guillén Ade J Guerrero-Barrera AL 《In vitro cellular & developmental biology. Animal》2011,47(10):681-688
A new system for sustained release of growth factors, such as osteogenic protein 1 (OP-1) and transforming growth factor β1
(TGF-β1), intended to repair and promote dental tissue regeneration in rats was designed and characterized in this work. The
release system was made with microparticles of sodium alginate, produced by ionic gelling dripping technique. The release
profiles of OP-1 and TGF-β1 from biopolymer matrix were determined by high-performance liquid chromatography (HPLC), and with
this purpose, an HPLC-UV method was developed. About 80% of each growth factor was released in the first 24 h, reaching almost
100% in 168 h. The system was tested during the tissue repair in rat molars in comparison with calcium hydroxide and both
growth factors not encapsulated. The dentin sialoprotein (DSP) was used as a repair marker. It was detected by immunohistochemistry,
after 14- and 28-d post-treatment. X
2 test (p ≤ 0.001) and Fisher exact test (p ≤ 0.05) were applied for assessment of the amount of immunostaining. The treatment with encapsulated OP-1 showed an increased
DSP immunostaining after 14 d and did not find any significant difference with the immunostaining observed for calcium hydroxide
treatment. Treatment with TGF-β1 did not show significant difference with calcium hydroxide. Treatment with both factors OP-1
and TGF-β1 showed higher DSP immunostaining in comparison with calcium hydroxide treatment. In conclusion, the combination
of both growth factors encapsulated showed more DSP immunostaining in comparison with each one separated, either encapsulated
or not. 相似文献
13.
Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the
treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute
to its neuroprotective and vasotropic effects. In this study, we investigated the effect of prolonged administration of EGb
761, up to 10 weeks, on mammalian retina using Fourier transform infrared spectroscopy (FTIR). Two main groups were involved
in this study: the normal group (n = 10); and EGb-administrated group (n = 50) that received—orally—a dose of 40 mg/kg/day EGb 761. The results demonstrated that EGb administration was associated
with different beneficial effects on the retinal constituents especially the underlying amide I protein secondary structure
components as well as the NH-OH region. It concluded that the optimum daily administration period of EGb (40 mg/kg) for ophthalmic
applications that targeting the retina ranges from 5 to 8 weeks. 相似文献
14.
The Absorption and Distribution of Strontium in Plants: I. PRELIMINARY STUDIES IN WATER CULTURE 总被引:2,自引:1,他引:1
The absorption and distribution of strontium in barley plantshas been studied, in water culture, both in the presence andabsence of calcium. Tracer methods have been employed. When no other bivalent ions were present in the external solutionthe absorption of strontium was proportional to the concentrationover a wide concentration range (106 to 101 m.equiv./l.).In the presence of calcium, however, absorption was reducedand appeared to be dependent on the total concentration of calciumplus strontium rather than on that of 8trontlum alone. The translocationof stron tium from the root to the shoot increased as the externalconcentration of both ions was raised. In plants of low initialcalcium status the rate of translocation of strontium was markedlyreduced, apparently because of its retention at or near theroot surface. Autoradiographs of plants treated with labelled strontium for24 hours at different stages of growth and grown subsequentlyfor varying periods of time in unlabelled nutrient solutionsshowed that very little redistribution of strontium occurredwithin the plant. Leaves which developed after treatment inthe labelled solutions contained little or no strontium evenwhen the concentration in the older leaves was very high. Strontiumwas initially retained in the nodes of the stems, but the greatestaccumulation was later found to be in the leaves which had beengrowing most actively at the time of absorption. 相似文献
15.
Błaszczyk I Birkner E Gutowska I Romuk E Chlubek D 《Biological trace element research》2012,146(3):335-339
Increased exposure to fluorine-containing compounds leads to accumulation of fluorides in hard tissues of bones and teeth,
which may result in numerous skeletal and dental disorders. This study evaluates the influence of methionine and vitamin E
on fluoride concentration in bones and teeth of rats subjected to long-term exposure to sodium fluoride in drinking water.
The study was conducted in 30 3-month-old female Wistar FL rats. The animals were divided into five groups, six rats per group.
The control group consisted of rats receiving only distilled water as drinking water. All other groups received NaF in the
amount of 10 mg/kg of body mass/day in their drinking water. In addition, respective animal groups received: NaF + Met group—10 mg
of methionine/kg of body mass/day, NaF + Met + E group—10 mg of methionine/kg of body mass/day and 3 mg of vitamin E (tocopheroli
acetas)/rat/day and NaF + E group—3 mg of vitamin E/rat/day. Femoral bones and incisor teeth were collected for the study,
and the fluoride concentration was determined using a fluoride ion-selective electrode. Fluoride concentration in both bones
and teeth was found to be higher in the NaF and NaF + Met groups compared to the control group. In groups NaF + Met + E and
NaF + E, the study material contained much lower fluoride concentration compared to the NaF group, while the effect was more
prominent in the NaF + E group. The results of the studies indicate that methionine and vitamin E have opposite effects on
accumulation of fluorides in hard tissue in rats. By stimulating fluoride accumulation, methionine reduces the adverse effect
of fluorides on soft tissue, while vitamin E, which prevents excessive accumulation of fluorides in bones and teeth, protects
these tissues from fluorosis. Therefore, it seems that combined application of both compounds would be optimal for the prevention
of the adverse effects of chronic fluoride intoxication. 相似文献
16.
The present study was conducted to investigate the sustained-release properties of Mimosa pudica seed mucilage. Matrix tablets of diclofenac sodium containing different proportions of mucilage and dibasic calcium phosphate
as diluent were formulated by wet granulation method. The tablets had uniform physical appearance, average weight, drug content,
and adequate hardness. The results of in vitro release conducted using USP type II dissolution rate apparatus, in a dissolution media comprising of 900 mL of 0.1 N HCl
for 2 h followed by phosphate buffer (pH 6.8) for 24 h at 37°C and 50 rpm, revealed that as the proportion of mucilage in
the matrix was increased there was a corresponding decrease in the release of drug. Further, the matrix tablets were found
to release the drug following Higuchi square root release kinetics, with the mechanism of release being diffusion for tablets
containing higher proportion of mucilage and a combination of matrix erosion and diffusion for tablets containing smaller
proportion of mucilage. The swelling and erosion studies revealed that, as the proportion of mucilage in tablets was increased,
there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets. The SEM photomicrographs
showed gelling structures in tablets containing higher percentage of mucilage, while both pores and gelling structures were
present on the surface of tablets containing smaller proportion of mucilage and commercial formulation. On comparative evaluation,
the dissolution profile from formulation containing mucilage to drug in the proportion of 1:40 was found to be similar to
the commercial sustained-release formulation of diclofenac. 相似文献
17.
The objective of this study was to prepare and characterize microparticles of budesonide alone and budesonide and polylactic acid (PLA) using supercritical fluid (SCF) technology. A precipitation with a compressed antisolvent (PCA) technique employing supercritical CO2 and a nozzle with 100-μm internal diameter was used to prepare microparticles of budesonide and budesonide-PLA. The effect of various operating variables (temperature and pressure of CO2 and flow rates of drug-polymer solution and/or CO2) and formulation variables (0.25%, 0.5%, and 1% budesonide in methylene chloride) on the morphology and size distribution of the microparticles was determined using scanning electron microscopy. In addition, budesonide-PLA particles were characterized for their surface charge and drug-polymer interactions using a zeta meter and differential scanning calorimetry (DSC), respectively. Furthermore, in vitro budesonide release from budesonide-PLA microparticles was determined at 37°C. Using the PCA process, budesonide and budesonide-PLA microparticles with mean diameters of 1 to 2 μm were prepared. An increase in budesonide concentration (0.25%–1% wt/vol) resulted in budesonide microparticles that were fairly spherical and less aggiomerated. In addition, the size of the microparticles increased with an increase in the drug-polymer solution flow rate (1.4–4.7 mL/min) or with a decrease in the CO2 flow rate (50–10 mL/min). Budesonide-PLA microparticles had a drug loading of 7.94%, equivalent to ∼80% encapsulation efficiency. Budesonide-PLA microparticles had a zeta potential of— 37±4 mV, and DSC studies indicated that SCF processing of budesonide-PLA microparticles resulted in the loss of budesonide crystallinity. Finally, in vitro drug release studies at 37°C indicated 50% budesonide release from the budesonide-PLA microparticles at the end of 28 days. Thus, the PCA process was successful in producing budesonide and budesonide-PLA microparticles. In addition, budesonide-PLA microparticles sustained budesonide release for 4 weeks. 相似文献
18.
The main objective of this study was to analyze the differences in profiles of RNase activities from triticale embryos (Triticosecale, cv. Ugo) between dormant and non-dormant caryopses and to determine the influence of exogenous abscisic acid (ABA) on the
activities of these enzymes. The major RNase from the examined tissue was detected following SDS-PAGE, with substrate-based
gel assay, described by Yen and Green (Plant Physiol 97:1487–1493, 1991). The activities of enzymes were characterized according to their pH optima, ion dependence, EDTA sensitivity and DNase activity.
In embryos with arrested growth (in a natural way by dormancy or artificially by ABA treatment), the activity of two enzymes—24
and 27 kDa—belonging to class I RNases was completely inhibited, whereas that of two other RNases of this family—23 and 25 kDa—was
detectable. However, the activity of the class I ribonucleases (enzymes responsible for cellular Pi release) was very low. Moreover, in contrast with non-dormant caryopses, imbibing embryos of dormant or ABA-treated seeds
contained 13- and 14-kDa enzymes. These enzymes have not been classified so far, and their specific properties are different
from the generally accepted properties of ribonucleolytic enzymes. In addition to the above results, the Pi content in the analyzed samples was determined by the Ames (Methods Enzymol 8:115–118, 1966) method. The results suggest a very low and constant level of inorganic phosphate in dormant samples as well as an evidently
decreasing Pi content in embryos under the influence of ABA treatment. The inhibition of the class I RNases activity induced by abscisic
acid implies that one of the roles of ABA in seed dormancy may consist in arresting the catabolic release of Pi, which results in retarding the embryo’s growth. 相似文献
19.
Ji-Yun Min Seung-Mi Kang Dong-Jin Park Yong-Duck Kim Ha-Na Jung Jae-Kyung Yang Won-Teak Seo Seon-Won Kim Chandrakant S. Karigar Myung-Suk Choi 《Biotechnology and Bioprocess Engineering》2006,11(4):372-376
Ferulic acid is a phenolic compound that serves as a major biosynthetic precursor of vanillin in higher plants. We investigated
the ability of the 3 commercial enzymes—Ultraflo L, Viscozyme L, and α-Amylase—to induce the release ferulic acid from theIpomoea batatas L. (sweet potato) stem. The rate of release for ferulic acid was optimal when Ultraflo L (1.0%) was used compared with the
other enzymes, whereas Viscozyme L was most effective for the release of vanillic acid and vanillin. Thus, these enzymes may
be useful for the large-scale production of ferulic acid and other phenolic compounds from sweet potato stem. 相似文献
20.
M. G. Tsilivakos S. K. Manolis O. Vikatou M. J. Papagrigorakis 《International Journal of Anthropology》2002,17(2):91-99
This study investigates the incidence of periodontitis in a Mycenaean population unearthed at the cemetery of Aghia Triada
(West Peloponnese, Greece) during the 1989–1997 field season. The material consists of 172 dry skulls. Demographic parameters
of sex and age were difficult to be assigned due to the bad state of preservation of the skeletal material. The ratio was
50 males, 48 females, 65 unidentified and 9 children, and we estimated an average age of 38 years. In this work we used traditional
and modern methods to determine the incidence of periodontitis in the archeological human dental bone. We also recorded other
dental diseases, such as ante mortem tooth loss, caries and attrition. The results showed that periodontitis has affected
35% of the jaws. A notable percentage of the individuals — 24% — lost three or more teeth during their lifetime and a total
53% of the population had extracted teeth before death. This paper points out that the ancient jaws present a high proportion
of ante-mortem tooth loss, attrition and deep caries, whereas the frequency of periodontitis does not seem to differ from
that of other prehistoric samples. 相似文献