scholarly journals Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro

1999 ◽  
Vol 18 (9) ◽  
pp. 552-559 ◽  
Author(s):  
T Platzek ◽  
C Lang ◽  
G Grohmann ◽  
U-S Gi ◽  
W Baltes
Keyword(s):  
Human Skin ◽  
Aromatic Amine ◽  
Azo Dyes ◽  
Reductase Activity ◽  
Safety Evaluation ◽  
Reaction Products ◽  
Healthy Human ◽  
Skin Bacteria ◽  
Skin Flora

Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 361011 cells of a culture of Staphylococcus aureus wereincubatedinsyntheticsweat (pH 6.8, final volume 20 mL) at 288C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3,3'-di methyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed.

841 Fractional CO2 Laser Increases in Vitro Intradermal Delivery of Vitamins in Human Skin

2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S260-S260
Author(s):  
Robert J Dabek ◽  
Branko Bojovic
Keyword(s):  
Minimally Invasive ◽  
Human Skin ◽  
Co2 Laser ◽  
Healthy Human ◽  
Burn Scar ◽  
Fractional Co2 Laser ◽  
Vitamin Content ◽  
Intradermal Delivery ◽  
Added Benefit

Abstract Introduction The morbidity associated with burn scar contractures remains high globally. Minimally invasive interventions with lasers are capable of decreasing morbidity through a process of scar rehabilitation. Laser interventions have the added benefit of increasing the intradermal delivery of topically applied drugs. Many substances, including vitamins with known roles in the integument, remain largely untested for their ability to potentiate the scar rehabilitation response seen in laser treated scars. Here we tested the ability of a fractional CO2 laser to increase the intradermal delivery of topically applied vitamins A and C. Methods Discarded healthy human skin from surgical procedures was collected. Skin was treated with fractional CO2 laser with a density of 3% and 5%, each at 2 different energy settings. A formulation of vitamin A and C was applied immediately to the laser treated skin as well as an untreated control. The skin was placed into a preservation device allowing diffusion of nutrients to the cells. Punch biopsies were taken at 6 hours and 48-hours after application of vitamins. Biopsies were analyzed using ELISA for vitamin content at 6 and 48-hours. Biopsies at 48-hours were analyzed using RT-PCR for RNA expression of several key regulators of wound healing. Results The CO2 laser was an effective tool to enhance the intradermal delivery of vitamins. Higher laser energies and densities offered an increase in vitamin content. Conclusions Treatment of skin with a fractional ablative CO2 laser is an effective modality for increasing intradermal delivery of topical vitamins A, C, and E. These results are promising in the search for optimal minimally invasive therapies to treat hypertrophic scars, as well as other dermatologic conditions. Applicability of Research to Practice The preliminary in vitro research has demonstrated the efficacy of fractional CO2 lasers to deliver vitamins intradermally. Further studies are underway to analyze the therapeutic effect of post-laser topical vitamin application on burn scars in the clinical setting.

Tissue and Bacterial Splitting of Sulphasalazine

1983 ◽  
Vol 64 (3) ◽  
pp. 349-354 ◽  
Author(s):  
A. K. Azad Khan ◽  
Glynis Guthrie ◽  
H. H. Johnston ◽  
S. C. Truelove ◽  
D. H. Williamson
Keyword(s):  
Azo Dyes ◽  
Enzyme System ◽  
Reductase Activity ◽  
Maximum Activity ◽  
The Other ◽  
Optimum Conditions ◽  
Anaerobic Conditions ◽  
Azo Reductase ◽  
Tissue Homogenates

1. The cleavage of sulphasalazine at the azo bond by bacterial suspensions and tissue homogenates has been studied in vitro. 2. For maximum activity the azo reductase system requires anaerobic conditions and the presence of cofactors, namely NADPH and FAD. in this respect, sulphasalazine resembles other azo dyes. 3. Under optimum conditions all the species of bacteria tested were capable of splitting sulphasalazine and there were no major differences in the degree of activity shown by different species. The enzyme system is located within the bacterial cell and does not leak out of it. 4. All the tissues tested, both human and rat, showed azo reductase activity. The liver showed a much higher activity than the other tissues.

scholarly journals Ecological effects of a deodorant and a plain soap upon human skin bacteria

1977 ◽  
Vol 78 (1) ◽  
pp. 1-10 ◽  
Author(s):  
David J. Bibel
Keyword(s):  
Human Skin ◽  
Analysis Of Variance ◽  
Individual Variation ◽  
Staphylococcus Epidermidis ◽  
Micrococcus Luteus ◽  
Acinetobacter Calcoaceticus ◽  
Skin Bacteria ◽  
Skin Flora ◽  
Significant Difference ◽  
The Impact

SUMMARYThe effects of a commercial trichlorocarbanilide-containing deodorant soap and a commercial plain soap upon the cutaneous flora of individuals were compared. Using a cross-over design, 21 volunteers (10 women and 11 men) washed their forearms at least once a day with one soap for 3 weeks and then switched soaps for another 4 weeks use. By analysis of variance no significant difference in total colony counts was noted among individuals in their use of the two soaps. With the exception of individual variation, neither sequence of use, sex, nor any combination was influential. However, in 20 of 21 subjects an alteration in the composition of skin flora was observed. The deodorant soap, which in six cases increased total flora, tended to reduce or eliminate diphtheroids in 12 of 17 carriers (71%). Fewer kinds of bacteria were also noted. MoreStaphylococcus epidermidiswas seen with the plain soap, but washing with the deodorant soap seemed to favourAcinetobacter calcoaceticusandMicrococcus luteus.The impact of this alteration and the use of total counts to measure effectiveness of deodorant soaps were brought into question.

scholarly journals Ocular Surface Cytotoxicity and Safety Evaluation of Tafluprost, a Recently Developed Anti-Glaucoma Prostaglandin Analog

2014 ◽  
Vol 6 ◽  
pp. OED.S12445 ◽  
Author(s):  
Yoshimi Niwano ◽  
Atsuo Iwasawa ◽  
Masahiko Ayaki
Keyword(s):  
Ocular Surface ◽  
Safety Evaluation ◽  
In Vitro Cytotoxicity ◽  
Conjunctival Hyperemia ◽  
Healthy Human ◽  
Upper Eyelid ◽  
Human Volunteers ◽  
Preservative Free ◽  
Viability Score

In vitro cytotoxicity of tafluprost, which is the most recently developed anti-glaucoma prostaglandin (PG) analog, in ocular surface cells is addressed in comparison with other PG analogs. Irrespective of cell lines and models, the cytotoxicity of anti-glaucoma PG eyedrops was primarily related to the concentration of benzalkonium chloride (BAK) contained in the eyedrops as a preservative. Accordingly, preservative-free tafluprost was apparently less cytotoxic than BAK-preserved PG analogs. Furthermore, our study for cytotoxicity assays on ocular cells, conducted by comprehensive investigations covering a variety of concentrations and treatment times, which is termed the cell viability score (CVS) system, demonstrated that 0.001% BAK-preserved tafluprost was not cytotoxic, and suggested that tafluprost may even reduce the cytotoxic effect of BAK. It has been reported that adverse reactions associated with tafluprost in healthy human volunteers and patients with glaucoma include conjunctival hyperemia, eyelid pigmentation, eyelash bristles, and deepening of upper eyelid sulcus. Nonetheless, most clinical studies have demonstrated that not only preservative-free tafluprost but also BAK-preserved tafluprost is well tolerated and safe in patients with glaucoma and ocular hypertension.

Desmosomal distribution in the epidermis of a non-contracting human skin equivalent

1992 ◽  
Vol 50 (1) ◽  
pp. 896-897
Author(s):  
L.X. Oakford ◽  
S.D. Dimitrijevich ◽  
R. Gracy
Keyword(s):  
Human Skin ◽  
Basal Layer ◽  
Skin Equivalent ◽  
Tissue Component ◽  
Intact Skin ◽  
Similar Sequence ◽  
Sequence Of Events ◽  
Suprabasal Keratinocytes ◽  
Human Skin Equivalent

In intact skin the epidermal layer is a dynamic tissue component which is maintained by a basal layer of mitotically active cells. The protective upper epidermis, the stratum corneum, is generated by differentiation of the suprabasal keratinocytes which eventually desquamate as anuclear comeocytes. A similar sequence of events is observed in vitro in the non-contracting human skin equivalent (HSE) which was developed in this lab (1). As a part of the definition process for this model of living skin we are examining its ultrastructural features. Since desmosomes are important in maintaining cell-cell interactions in stratified epithelia their distribution in HSE was examined.

Gastroretentive Floating Capsules of Risedronate Sodium: Development, Optimization, in vitro and in vivo Evaluation in Healthy Human Volunteers

2015 ◽  
Vol 8 (2) ◽  
pp. 2835-2842
Author(s):  
Bhikshapathi D. V. R. N. ◽  
Arun Kumar Jarathi ◽  
Suresh Gande ◽  
Viswaja Medipally ◽  
Ramesh Bomma
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Zero Order ◽  
Wet Granulation ◽  
Capsule Formulation ◽  
In Vivo Evaluation ◽  
Healthy Human ◽  
X Ray ◽  
Human Volunteers

Background and the purpose of the study: Risedronate sodium inhibits osteoclast bone resorption and modulates bone metabolism. Risedronate has a high affinity for hydroxyapatite crystals in bone and is a potent antiresorptive agent. In the present investigation efforts were made to improve the bioavailability of risedronate sodium by increasing the residence time of the drug through sustained-release matrix capsule formulation via gastroretentive mechanism. Capsules were prepared by wet granulation technique. The influence of gel forming agents, amount of risedronate and total weight of capsules on physical properties, in vitro buoyancy, drug release, FTIR, DSC, X-ray studies were investigated. The release mechanisms were explored and explained by applying zero order, first order, Higuchi and Korsmeyer equations. The selected formulations were subjected to stability study at 40 °C/75% RH, 25 °C/60% RH for the period of three months. For all formulations, kinetics of drug release from capsules followed Higuchi’s square root of time kinetic treatment heralding diffusion as predominant mechanism of drug release. Formulation containing 25 mg HPMC K4M and 75 mg HPMC K100 LV (F-8) showed zero order release profile. There was no significant change in the selected formulation, when subjected to accelerated stability conditions over a period of three months. X-ray imaging in six healthy human volunteers revealed a mean gastric retention period of 5.60 ± 0.77 hrs for the selected formulation. Stable, sustained release effervescent floating capsules of risedronate sodium could be prepared by wet granulation technique.  

Human Skin-Derived Fibroblasts Acquire In Vitro Anti-Tumor Potential after Priming with Paclitaxel

2013 ◽  
Vol 13 (3) ◽  
pp. 523-530 ◽  
Author(s):  
Augusto Pessina ◽  
Valentina Cocce ◽  
Arianna Bonomi ◽  
Loredana Cavicchini ◽  
Francesca Sisto ◽  
...  
Keyword(s):  
Human Skin

The Effect of Practolol, In Vitro Generated Metabolites of Practolol and Chemical Analogues on the Rate of Growth of Human Skin Fibroblasts

1984 ◽  
Vol 12 (2) ◽  
pp. 89-97
Author(s):  
Graham R. Elliott ◽  
H.E. Amos ◽  
James W. Bridges
Keyword(s):  
Human Skin ◽  
Psoriasis Patient ◽  
Skin Fibroblasts ◽  
Human Skin Fibroblasts ◽  
Cell Type ◽  
Normal Human Skin ◽  
Rate Of Growth ◽  
Structural Analogues ◽  
Normal Human

The rate of growth of normal human skin fibroblasts was inhibited in a dose related, reversible, fashion by practolol (N-4-(2-hydroxy)-3 (1-methyl)-aminopropoxyphenylacetamine) (ID50 1.35 ± 0.14 x 10-3M), propranolol (1-(isopropylamino)-3(1-naphthyl-oxy)-2-propranolol) (ID50 0.145 ± 0.02 x 10-3M) and paracetamol (N-(4-hydroxyphenyl) acetamide) (ID50 0.85 ± 0.2 x 10-3M). Skin fibroblasts isolated from a psoriasis patient were more sensitive towards practolol (ID50 0.48 ± 0.14 x 10-3M) and propranolol (ID50 0.032 ± 0.002 x 10-3M), but less sensitive towards paracetamol (ID50 1.3 ± 0.07 x 10-3M). In vitro generated metabolites of practolol, using normal or Arochlor 1254-pretreated hamster liver preparations, and structural analogues of practolol had no effect upon the growth of either cell type.

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