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91.
The bioavailability of therapeutic agents from eye drops is usually limited due to corneal barrier functions and effective
eye protective mechanisms. Therefore, the current study aims to enhance ocular bioavailability of brimonidine, a potent antiglaucoma
drug, through the preparation of ocular inserts. Solvent casting technique was employed to prepare the inserts using polyvinylpyrrolidone
K-90 (PVP K-90) as film-forming polymer blended with different viscosity grades of bioadhesive polymers namely hydroxypropyl
methycellulose, carbopol, sodium alginate, and chitosan. The prepared ocular inserts were evaluated for various physicochemical
parameters, swelling behavior, and in vitro release patterns. Sodium alginate-based ocular inserts revealed the most sustainment in drug release (99% at 6 h), so it
was selected for further modifications via coating it, on one side or dual sides, using hydrophobic film composed of either
ethylcellulose or Eudragit RSPO. The obtained in vitro release results for the modified ocular inserts revealed that ethylcellulose is superior to Eudragit RSPO in terms of brimonidine
release sustainment effect. Ocular inserts composed of 7% PVP K-90, 1.5% low molecular weight sodium alginate with or without
ethylcellulose coat were able to sustain the in vitro release of brimonidine. Their therapeutic efficacy regarding intraocular pressure (IOP) lowering effect when inserted in
albino rabbits eyes showed superior sustainment effect compared with that of brimonidine solution. Furthermore, due to both
the mucoadhesive property and the drug sustainment effect, the one-side-coated ocular insert showed more IOP lowering effect
compared with that of its non-coated or dual-side-coated counterpart. 相似文献
92.
Habib Hamidinezhad Yussof Wahab Zulkafli Othaman Abd Khamim Ismail 《Plasmonics (Norwell, Mass.)》2011,6(4):791-796
Silicon nanonowires (SiNWs) were synthesized with approximately 100 nm/min by very-high-frequency plasma-enhanced chemical
vapor deposition method via a vapor–liquid–solid mechanism. Pure silane gas was deposited on Au-coated silicon substrates
at various radio frequency (RF) powers varied from 5 to 20 W, keeping other deposition parameters constant. Synthesized SiNWs
were needle-like shape with an ultra-sharp tip diameter of about 10 nm and a length about 3 μm, which differs from the standard
cylindrical nanowire produced by similar techniques. Furthermore, it was shown that the average length of nanoneedles augmented
with the increase of RF power. High-resolution transition electron microscopy displayed that the nanowires were composed of
a crystalline Si core with an amorphous oxide shell. Raman spectroscopy also revealed the presence of crystalline Si in the
grown Si nanoneedles. 相似文献
93.
Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs to the repeats-in-toxin family, is believed to be one of its virulence factors and to have an important role in the bacterium''s pathogenicity. This toxin selectively kills human leukocytes by inducing apoptosis and lysis. Here, we report that leukotoxin-induced cell death of macrophages proceeded through a process that differs from the classical characteristics of apoptosis and necrosis. A. actinomycetemcomitans leukotoxin-induced several cellular and molecular mechanisms in human macrophages that led to a specific and excessive pro-inflammatory response with particular secretion of both interleukin (IL)-1β and IL-18. In addition, this pro-inflammatory cell death was inhibited by oxidized ATP, which indicates involvement of the purinergic receptor P2X7 in this process. This novel virulence mechanism of the leukotoxin may have an important role in the pathogenic potential of this bacterium and can be a target for future therapeutic agents. 相似文献
94.
Esmat M. Hegazi Maria A. Konstantopoulou Annette Herz Wedad E. Khafagi Essam Agamy Sania Showiel Atwa Atwa Gehan M. Abd El‐Aziz Safaa M. Abdel‐Rahman 《Insect Science》2011,18(5):565-574
Abstract Prays oleae Bern, (OM) and Palpita unionalis Hüb., (JM) are two of the most important pests in olive groves in Egypt. A 3‐year monitoring study using sex pheromone traps in semi‐arid and arid olive groves was performed. In the semi‐arid grove, flight pattern of the OM was the same as in other Mediterranean countries, but in dates concordating plant phenology. The moth completes three generations annually: the first flight is in March to April, the second is in May to June and the third occurs in August to October. In the arid olive grove, an interesting flight pattern was observed. First flight was always very close or overlapped with the second one with no male catches during August to October. However, eggs were present most of the season, indicating unusually high female presence and oviposition activity of the OM during the absence of males in the traps. Generally, moth densities were significantly lower in low fruiting years than in higher ones and were also lower in the arid olive grove than in the semi‐arid one. In contrast, JM males were present all season, exhibiting six to seven and three to four overlapping flight peaks in arid and semi‐arid olive groves, respectively. Moth densities were significantly higher in the arid olive grove than those in the semi‐arid one. This study shows that trapping location and fruit bearing year are characteristics that strongly affect the grove‐specific information needed to estimate correctly adult emergence and thus the timing of control measures. 相似文献
95.
Ohgawara T Kubota S Kawaki H Kurio N Abd El Kader T Hoshijima M Janune D Shimo T Perbal B Sasaki A Takigawa M 《Journal of cell communication and signaling》2011,5(4):291-299
The CCN family of proteins consists of six members with conserved structural features. These proteins play several roles in the physiology and pathology of cells. Among the pathological roles of the CCN family, one of the most important and controversial ones is their role in the expansion and metastasis of cancer. Up to now a number of reports have described the possible role of each CCN family member independently. In this study, we comprehensively analyzed the roles of all six CCN family members in cell growth, migration and invasion of breast cancer cells in vitro and in vivo. As a result, we found the CCN2/CCN3 ratio to be a parameter that is associated with the metastatic phenotype of breast cancer cells that are highly metastatic to the bone. The same analysis with cell lines from oral squamous carcinomas that are not metastatic to the bone further supported our notion. These results suggest the functional significance of the interplay between CCN family members in regulating the phenotype of cancer cells. 相似文献
96.
OBJECTIVE: To report a patient with an unusual presentation of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) and severe keratopathy. CASE HISTORY: An Egyptian male sustained an injury to the left eye at 13 years of age and was found to have corneal damage which was attributed to the injury. Subsequently, however, he continued to have sore eyes with photophobia. A year later he became weak with pigmentation and episodes of collapse, and investigation showed that he had Addison's disease together with mucocutaneous candidiasis. At 15 years of age he developed carpo-pedal spasm and was found to have hypoparathyroidism with intracranial calcification. At 20 years of age the ophthalmic diagnosis was revised to keratopathy by which time the patient had corneal opacity and problems with visual acuity, especially in the right eye. Investigation at 22 years of age showed that he was homozygous for an R139X mutation in the gene encoding the AIRE protein, a mutation which to date has only been found in Sardinian patients. CONCLUSIONS: Keratopathy can be an early and severe manifestation of APECED, requiring expert ophthalmic care. Its presence should prompt a search for other components of APECED, some of which are life-threatening. 相似文献
97.
Steadily growing use of electromagnetic fields, especially in conjunction with wireless communication systems, has led to increasing public concern about possible health effects of electromagnetic radiation. However, besides the well-known thermal effect of electromagnetic fields on biological tissue, there is no clear evidence of further athermal interaction mechanisms with biological systems. The present study was designed to determine the changes in bilayer permeability in egg lecithin multilamellar vesicles after exposure to 900 MHz microwave radiation for a period of 5 h. Specific absorption rate (SAR) of the radiation for the investigated liposome sample was found to be 12 +/- 1 W/kg. Liposomal changes in permeability were monitored using a light scattering technique. Optical anisotropy of the liposome sample decreased dramatically upon exposure to microwave radiation, indicating structural changes in acyl chain packing. IR and NMR ((1)H NMR) studies, which have been employed to reveal structural alterations in microwave, exposed vesicles showed an increased damage upon exposure to microwave. The changes observed in the (1)H NMR spectrum of the microwave exposed sample indicated hydrolysis of carboxylic and phosphoric esters. IR study showed conformational changes in the acyl chains of the lipids upon microwave exposure. However, both IR and (31)P NMR did not show any appreciable changes in the head group part of the lipids. 相似文献
98.
The schistosomicidal properties of Nigella sativa seeds were tested in vitro against Schistosoma mansoni miracidia, cercariae, and adult worms. Results indicate its strong biocidal effects against all stages of the parasite and also showed an inhibitory effect on egg-laying of adult female worms. In the present work we also studied the effects of crushed seeds on some antioxidant enzymes; which have a role in protection of adult worms against host oxidant killing; as well as some enzymes of glucose metabolism; which have a crucial role in the survival of adult worms inside their hosts. The data revealed that the used drug induce an oxidative stress against adult worms which indicated by a decrease in the activities of both antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and glutathione reductase and enzymes of glucose metabolism, hexokinase and glucose-6-phosphate dehydrogenase. Disturbing of such enzymes of adult worms using N. sativa seeds could in turn render the parasite vulnerable to damage by the host and may play a role in the antischistosomal potency of the used drug. 相似文献
99.
Real-time nucleic acid sequence-based amplification assay for detection of hepatitis A virus 总被引:1,自引:0,他引:1
Abd el-Galil KH el-Sokkary MA Kheira SM Salazar AM Yates MV Chen W Mulchandani A 《Applied and environmental microbiology》2005,71(11):7113-7116
A nucleic acid sequence-based amplification (NASBA) assay in combination with a molecular beacon was developed for the real-time detection and quantification of hepatitis A virus (HAV). A 202-bp, highly conserved 5' noncoding region of HAV was targeted. The sensitivity of the real-time NASBA assay was tested with 10-fold dilutions of viral RNA, and a detection limit of 1 PFU was obtained. The specificity of the assay was demonstrated by testing with other environmental pathogens and indicator microorganisms, with only HAV positively identified. When combined with immunomagnetic separation, the NASBA assay successfully detected as few as 10 PFU from seeded lake water samples. Due to its isothermal nature, its speed, and its similar sensitivity compared to the real-time RT-PCR assay, this newly reported real-time NASBA method will have broad applications for the rapid detection of HAV in contaminated food or water. 相似文献
100.
Gökbel H Baltaci AK Uçok K Okudan N Mogulkoç R 《Biological trace element research》2005,106(3):247-252
This study aimed to investigate the possible changes in serum leptin concentration caused by acute exercise and the effects
of zinc deficiency on these changes. Forty male rats were divided into control-control, control-elercise, zinc-deficient-control,
and zinc-deficient-exercise groups (10 rats in each). Control-exercise and zinc-deficient-exercise groups performed exercisse
at 6 m/min speed on a rodent treadmill for 60 min or until exhaustion. All rats were decapitated 48h after the exercise, and
blood samples were collected to determine serum leptin and zinc levels. Serum leptin levels in the zinc-deficient-control
group were lower than in the control-control group. The mean exercise time of control-exercise group was significantly longer
than the zinc-deficient-exercise group. We conclude that serum leptin levels significantly decrease both 48 h after strenuous
exercise and in the zinc-deficient rats, and there is a further decrease in leptin levels when rats fed on a zinc-deficient
diet performed exercise. 相似文献