Cross‐Linking of Gelatin Capsules and Its Relevance to Their in Vitro-in Vivo Performance

1994 ◽  
Vol 83 (7) ◽  
pp. 915-921 ◽  
Author(s):  
George A. Digenis ◽  
Thomas B. Gold ◽  
Vinod P. Shah
Keyword(s):  
Cross Linking ◽  
Gelatin Capsules

ChemInform Abstract: Cross-Linking of Gelatin Capsules and Its Relevance to Their in vitro- in vivo Performance

ChemInform ◽  
2010 ◽  
Vol 26 (1) ◽  
pp. no-no
Author(s):  
G. A. DIGENIS ◽  
T. B. GOLD ◽  
V. P. SHAH
Keyword(s):  
Cross Linking ◽  
Gelatin Capsules

scholarly journals Additional evidence for a proform to tropoelastin from chick aorta

1979 ◽  
Vol 177 (2) ◽  
pp. 559-567 ◽  
Author(s):  
C S Heng-Khoo ◽  
R B Rucker ◽  
K W Buckingham
Keyword(s):  
Basic Protein ◽  
Cross Linking ◽  
Protein Subunit ◽  
Deficient Diet ◽  
Culture In Vitro ◽  
One Step

Evidence is presented for the presence of precursor to tropoelastin in chick arterial extracts. The precursor is approx. 100 000 daltons in size. It is suggested to be a precursor to tropoelastin (72 000 daltons). This protein may be observed in culture in vitro if appropriate precautions are taken to inhibit proteolysis. Once synthesized, it appears to be converted into tropoelastin within 10–20 min. The protein may also be detected in vivo. When 1-day-old cockerels were fed on a copper-deficient diet (less than 1 p.p.m. to inhibit cross-linking) containing epsilon-aminohexanoic acid (0.2%) to retard proteolysis and then injected wiht [3H]valine, extraction of arterial proteins 12h after injection resulted in detection of two major peaks of [3H]valine-labelled protein with pI values of pH 7.0 and 5.0 respectively. The protein that focused at pH 7.0 was estimated to be about 100 000 daltons in size and could be shown to be converted into a more basic protein with the properties of tropoelastin. It is speculated that the protein with pI 5.0 may be yet another extension peptide. The data appear to be in keeping with similar observations by ourselves and others that a proform of tropoelastin exists, and, in at least one step before conversion into tropoelastin, exists as a 100 000-dalton protein subunit.

scholarly journals Antigenicity of the infected-erythrocyte and merozoite surfaces in Falciparum malaria.

1979 ◽  
Vol 150 (5) ◽  
pp. 1241-1254 ◽  
Author(s):  
S G Langreth ◽  
R T Reese
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Infected Erythrocyte ◽  
Falciparum Infection ◽  
Human Erythrocytes ◽  
Cross Linking ◽  
Common Antigens

The antigenicity of altered structures induced by Plasmodium falciparum in the membranes of infected Aotus monkey and human erythrocytes was examined. Antisera were obtained from monkeys made immune to malaria. Bound antibodies were shown to be localized on the knob protrusions of infected erythrocytes of both human and monkey origin and from both in vitro and in vivo infections. Therefore, P. falciparum infection has produced similar antigenic changes in the erythrocyte surfaces of both man and monkey. Uninfected erythrocytes and all knobless-infected erythrocytes bound no antibody from immune sera. Strains of P. falciparum from widely different geographic areas that were cultured in vitro in human erythrocytes induced structures (knobs) which have common antigenicity. Merozoites were agglutinated by cross-linking of their cell coats when incubated with immune sera. The binding of ferritin-labeled antibody was heavy on the coats of both homologous and heterologous strains of the parasite, indicating that the merozoite surfaces of these strains share common antigens.

scholarly journals Microtubule Actin Cross-Linking Factor (Macf)

1999 ◽  
Vol 147 (6) ◽  
pp. 1275-1286 ◽  
Author(s):  
Conrad L. Leung ◽  
Dongming Sun ◽  
Min Zheng ◽  
David R. Knowles ◽  
Ronald K.H. Liem
Keyword(s):  
Calcium Binding ◽  
Coiled Coil ◽  
Specific Protein ◽  
Binding Domain ◽  
Full Length ◽  
Actin Binding ◽  
Cross Linking ◽  
Actin Binding Domain

We cloned and characterized a full-length cDNA of mouse actin cross-linking family 7 (mACF7) by sequential rapid amplification of cDNA ends–PCR. The completed mACF7 cDNA is 17 kb and codes for a 608-kD protein. The closest relative of mACF7 is the Drosophila protein Kakapo, which shares similar architecture with mACF7. mACF7 contains a putative actin-binding domain and a plakin-like domain that are highly homologous to dystonin (BPAG1-n) at its NH2 terminus. However, unlike dystonin, mACF7 does not contain a coiled–coil rod domain; instead, the rod domain of mACF7 is made up of 23 dystrophin-like spectrin repeats. At its COOH terminus, mACF7 contains two putative EF-hand calcium-binding motifs and a segment homologous to the growth arrest–specific protein, Gas2. In this paper, we demonstrate that the NH2-terminal actin-binding domain of mACF7 is functional both in vivo and in vitro. More importantly, we found that the COOH-terminal domain of mACF7 interacts with and stabilizes microtubules. In transfected cells full-length mACF7 can associate not only with actin but also with microtubules. Hence, we suggest a modified name: MACF (microtubule actin cross-linking factor). The properties of MACF are consistent with the observation that mutations in kakapo cause disorganization of microtubules in epidermal muscle attachment cells and some sensory neurons.

scholarly journals The Effect of Oxidized Dopamine on the Structure and Molecular Chaperone Function of the Small Heat-Shock Proteins, αB-Crystallin and Hsp27

2021 ◽  
Vol 22 (7) ◽  
pp. 3700
Author(s):  
Junna Hayashi ◽  
Jennifer Ton ◽  
Sparsh Negi ◽  
Daniel E. K. M. Stephens ◽  
Dean L. Pountney ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Aggregation ◽  
Molecular Chaperone ◽  
Cross Linking ◽  
Αb Crystallin ◽  
The Cross ◽  
Shock Proteins ◽  
And Function

Oxidation of the neurotransmitter, dopamine (DA), is a pathological hallmark of Parkinson’s disease (PD). Oxidized DA forms adducts with proteins which can alter their functionality. αB-crystallin and Hsp27 are intracellular, small heat-shock molecular chaperone proteins (sHsps) which form the first line of defense to prevent protein aggregation under conditions of cellular stress. In vitro, the effects of oxidized DA on the structure and function of αB-crystallin and Hsp27 were investigated. Oxidized DA promoted the cross-linking of αB-crystallin and Hsp27 to form well-defined dimer, trimer, tetramer, etc., species, as monitored by SDS-PAGE. Lysine residues were involved in the cross-links. The secondary structure of the sHsps was not altered significantly upon cross-linking with oxidized DA but their oligomeric size was increased. When modified with a molar equivalent of DA, sHsp chaperone functionality was largely retained in preventing both amorphous and amyloid fibrillar aggregation, including fibril formation of mutant (A53T) α-synuclein, a protein whose aggregation is associated with autosomal PD. In the main, higher levels of sHsp modification with DA led to a reduction in chaperone effectiveness. In vivo, DA is sequestered into acidic vesicles to prevent its oxidation and, intracellularly, oxidation is minimized by mM levels of the antioxidant, glutathione. In vitro, acidic pH and glutathione prevented the formation of oxidized DA-induced cross-linking of the sHsps. Oxidized DA-modified αB-crystallin and Hsp27 were not cytotoxic. In a cellular context, retention of significant chaperone functionality by mildly oxidized DA-modified sHsps would contribute to proteostasis by preventing protein aggregation (particularly of α-synuclein) that is associated with PD.

Preparation, Characterization and In Vitro Release Kinetics of Vancomycin Carried β-TCP/Chitosan Composite Microspheres Used as Bone Tissue Engineering Scaffolds

2012 ◽  
Vol 512-515 ◽  
pp. 1821-1825
Author(s):  
Lin Zhang ◽  
Xue Min Cui ◽  
Qing Feng Zan ◽  
Li Min Dong ◽  
Chen Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Cross Linking ◽  
Tissue Engineering Scaffolds ◽  
Composite Microspheres ◽  
Chitosan Composite ◽  
Vitro Release

A novel microsphere scaffolds composed of chitosan and β-TCP containing vancomycin was designed and prepared. The β-TCP/chitosan composite microspheres were prepared by solid-in-water-in-oil (s/w/o) emulsion cross-linking method with or without pre-cross-linking process. The mode of vancomycin maintaining in the β-TCP/chitosan composite microspheres was detected by Fourier transform infrared spectroscopy (FTIR). The in vitro release curve of vancomycin in simulated body fluid (SBF) was estimated. The results revealed that the pre-cross-linking prepared microspheres possessed higher loading efficiency (LE) and encapsulation efficiency (EE) especially decreasing the previous burst mass of vancomycin in incipient release. These composite microspheres got excellent sphere and well surface roughness in morphology. Vancomycin was encapsulated in composite microspheres through absorption and cross-linking. While in-vitro release curves illustrated that vancomycin release depond on diffusing firstly and then on the degradation ratio later. The microspheres loading with vancomycin would be to restore bone defect, meanwhile to inhibit bacterium proliferation. These bioactive, degradable composite microspheres have potential applications in 3D tissue engineering of bone and other tissues in vitro and in vivo.

scholarly journals Formulation of Broccoli Sprout Powder in Gastro-Resistant Capsules Protects against the Acidic pH of the Stomach In Vitro but Does Not Increase Isothiocyanate Bioavailability In Vivo

Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 359
Author(s):  
Masuma Zawari ◽  
Bettina Poller ◽  
Greg Walker ◽  
Andree Pearson ◽  
Mark Hampton ◽  
...  
Keyword(s):  
The United States ◽  
Potential Health ◽  
Gelatin Capsules ◽  
Protein Levels ◽  
Dissolution Studies ◽  
Complete Disintegration ◽  
Enteric Coated ◽  
Broccoli Sprout

Broccoli sprout powder is a rich source of glucosinolates, which are hydrolysed to isothiocyanates in the presence of the enzyme myrosinase. We showed that in vitro incubation of broccoli sprout powder extract with isolated lymphocytes resulted in the upregulation of transcription factor Nrf2, however, there was no increase in Nrf2 protein levels in lymphocytes isolated 3 h following the ingestion of broccoli sprout powder by healthy volunteers. This highlights the general issue that potential health benefits of food-derived compounds can be compromised by limitations in bioavailability. In vitro experiments showed that the generation of isothiocyanates was reduced when the powder was first exposed to the low pH (1.2) of the stomach and then transferred to the higher pH (6.8) of the intestine. The loss of activity due to pre-exposure to the low stomach pH indicates that formulating the broccoli sprout powder in gastro-resistant formulations should increase that amount of isothiocyanate generated in the intestine for absorption. Gelatin capsules were hand-coated with either Eudragit® L100 or Eudragit® L100-55 and were assessed for their gastro-resistant properties using paracetamol as a model active for dissolution studies. Disintegration and dissolution studies showed that Eudragit® L100-55 coated capsules and DRcapsTM (Capsugel®) failed the United States Pharmacopeia (USP) requirements for gastro-resistant capsules, whereas the Eudragit® L100 coated capsules passed. Five healthy participants were administered 1 g of broccoli sprout powder, ingested either with water or encapsulated in uncoated or gastro-resistant capsules. Urinary excretion of isothiocyanate metabolites over the 24 h period post ingestion was assessed by HPLC. Broccoli sprout powder and uncoated gelatin-encapsulated powder showed comparable excretion of isothiocyanate metabolites (18.4 ± 2.3 and 23.9 ± 2.7 µmol, respectively). The enteric coated capsules provided a significantly longer Tmax than the uncoated gelatin capsules (15.4 ± 2.3 versus 3.7 ± 0.7 h, respectively), indicating protection from disintegration in the stomach, however, the excretion of isothiocyanate metabolites was significantly decreased compared with uncoated capsules (i.e., 8.5 ± 1.1 µmol). The lower in vivo formation or absorption of isothiocyanates observed for the gastro-resistant capsules may be due to participant variation in intestinal pH or transit times, resulting in inappropriate pH conditions or insufficient time for the complete disintegration and dissolution of the capsules.

scholarly journals Preparation and preclinical evaluation of aceclofenac loaded pectinate mucoadhesive microspheres

2012 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
Santanu Chakraborty ◽  
Priyanka Nayak ◽  
Bala Murali Krishna ◽  
Madhusmruti Khandai ◽  
Ashoke Kumar Ghosh
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Polymer Concentration ◽  
Research Work ◽  
In Vivo Studies ◽  
Systemic Absorption ◽  
Cross Linking ◽  
Significant Difference

The aim of the present research work was to fabricate aceclofenac loaded pectinate microspheres by ionic gelation method and evaluate the effect of different cross-linking agents and polymer concentration on particle size, encapsulation efficacy and drug release behavior. It was also investigated that whether this pectinate dosage form was able to target the drug release in intestinal region and prevent the different side effect associated with the drug in stomach or not. It was observed that particle size, encapsulation efficacy and in vitro drug release were largely depended on polymer concentration and cross-linking agents. It was also observed that pectinate microspheres showed excellent pH depended mucoadhesive properties and they were able to restrict the drug release in stomach. <em>In vitro</em> drug release study showed that alminium-pectinate microspheres have more sustaining property as compared to barium-pectinate microspheres. Holm-Sidak multiple comparison analysis suggested a significant difference in measured t<sub>50%</sub> values among all the formulations with same cross-linking agent. In vivo studies revealed that the anti inflammatory and analgesic effects induced by pectinate microspheres were significantly high and prolonged as compared to pure drug. So, pectinate microspheres can be an excellent carrier for targeting the delivery of aceclofenac as well as help in improving the patient compliance by prolonging the systemic absorption.

scholarly journals Arrangement of the Translocator of the Autotransporter Adhesin Involved in Diffuse Adherence on the Bacterial Surface

2005 ◽  
Vol 73 (7) ◽  
pp. 3851-3859 ◽  
Author(s):  
Daniel Müller ◽  
Inga Benz ◽  
Damini Tapadar ◽  
Christian Buddenborg ◽  
Lilo Greune ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Protein Translocation ◽  
Gel Filtration ◽  
Analytical Techniques ◽  
Cross Linking ◽  
Secretion Systems ◽  
Bacterial Surface ◽  
Passenger Proteins

ABSTRACT Autotransporters of gram-negative bacteria are single-peptide secretion systems that consist of a functional N-terminal α-domain (“passenger”) fused to a C-terminal β-domain (“translocator”). How passenger proteins are translocated through the outer membrane has not been resolved, and at present essentially three different models are discussed. In the widely accepted “hairpin model” the passenger proteins are translocated through a channel formed by the β-barrel of the translocator that is integrated in the outer membrane. This model has been challenged by a recent proposal for a general autotransporter model suggesting that there is a hexameric translocation pore that is generated by the oligomerization of six β-domains. A third model suggests that conserved Omp85 participates in autotransporter integration and passenger protein translocation. To examine these models, in this study we investigated the presence of putative oligomeric structures of the translocator of the autotransporter adhesin involved in diffuse adherence (AIDA) in vivo by cross-linking techniques. Furthermore, the capacity of isolated AIDA fusion proteins to form oligomers was studied in vitro by several complementary analytical techniques, such as analytical gel filtration, electron microscopy, immunogold labeling, and cross-linking of recombinant autotransporter proteins in which different passenger proteins were fused to the AIDA translocator. Our results show that the AIDA translocator is mostly present as a monomer. Only a fraction of the AIDA autotransporter was found to form dimers on the bacterial surface and in solution. Higher-order structures, such as hexamers, were not detected either in vivo or in vitro and can therefore be excluded as functional moieties for the AIDA autotransporter.

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