Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.116
Filtrar
1.
BMC Med Genomics ; 17(1): 178, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38965556

RESUMO

BACKGROUND: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. METHODS: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. RESULTS: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. CONCLUSION: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.


Assuntos
Consanguinidade , Proteínas de Transporte de Nucleosídeos , Linhagem , Humanos , Feminino , Proteínas de Transporte de Nucleosídeos/genética , Masculino , Adolescente , Criança , Mutação , Histiocitose/genética , Histiocitose/patologia , Simulação por Computador , Hipertricose/genética , Sequenciamento do Exoma , Contratura , Perda Auditiva Neurossensorial
2.
Front Oncol ; 14: 1396819, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38974235

RESUMO

Background: Currently, there is no standard treatment for relapsed/refractory NK/T-cell lymphoma (NKTCL). Liposomal mitoxantrone (Lipo-MIT) showed good anti-tumor effect in patients with NKTCL, breaking the limitation of natural resistance of NKTCL to anthracyclines. To further improve the efficacy, we tried a combination therapy based on Lipo-MIT in patients with relapsed/refractory NKTCL. Methods: 12 patients with relapsed/refractory NKTCL were enrolled in this retrospective study, all of whom had previously received pegaspargase-based treatments. The salvage treatment was a combination regimen based on Lipo-MIT. The efficacy was evaluated after every two cycles. Results: 11 patients had stage IV NKTCL, and all but one patients had an NRI score of ≥3. The median previous lines of treatment was two (range, 1-4), and five patients were refractory to their last line of treatment. The best response rates were as follows: complete response (CR) in five (41.7%) patients, partial response in five (41.7%) patients, stable disease in one (8.3%) patient, and progressive disease in one (8.3%) patient. At a median follow-up of four months (range, 2-14), seven patients died, with a median PFS of five months and a median OS of seven months. The six-month PFS and OS rate was 44.4% and 52.1%, respectively. All patients had suffered from side effects, among which myelosuppression was most reported. Nine patients had grade three or more myelosuppression, and the median recovery time from myelosuppression was 14 days (2-35 days). Five patients had obvious skin hyperpigmentation, and the CR rate was significantly higher compared with those without skin hyperpigmentation (80% vs. 14.3%, p=0.023). Other side effects included liver insufficiency (N=4), coagulation dysfunction (N=4), acute pancreatitis (N=2), and immunotherapy-related adverse effects (irAEs, N=2). Conclusion: Combination therapy based on Lipo-MIT has a high remission rate for relapsed/refractory NKTCL, but the duration of remission needs to be further extended. Lipo-MIT has obvious myelosuppression toxicity, and active supportive therapy should be given when combined with other cytotoxic drugs.

3.
Am J Ophthalmol ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38944135

RESUMO

PURPOSE: The association between the total macular burden of hyperreflective foci (HRF) in eyes with intermediate AMD (iAMD) and the onset of persistent choroidal hypertransmission defects (hyperTDs) was studied using swept-source optical coherence tomography (SS-OCT). DESIGN: Post hoc subgroup analysis of a prospective study. METHODS: A retrospective review of iAMD eyes from subjects enrolled in a prospective SS-OCT study was performed. All eyes underwent 6×6 mm SS-OCT angiography (SS-OCTA) imaging at baseline and follow-up visits. En face sub-retinal pigment epithelium (subRPE) slabs with segmentation boundaries positioned 64-400 µm beneath Bruch's membrane (BM) were used to identify persistent choroidal hyperTDs. None of the eyes had persistent hyperTDs at baseline. The same subRPE slab was used to identify choroidal hypotransmission defects (hypoTDs) attributable to HRF located either intraretinally (iHRF) or along the RPE (rpeHRF) based on corresponding B-scans. A semiautomated algorithm was used by two independent graders to validate and refine the HRF outlines. The HRF area and the drusen volume within a 5mm fovea-centered circle were measured at each visit. RESULTS: The median follow-up time for the 171 eyes from 121 patients included in this study was 59.1 months (95%CI: 52.0-67.8 months). Of these, 149 eyes (87%) had HRF, and 82 (48%) developed at least one persistent hyperTD during the follow-up. Although univariable Cox regression analyses showed that both drusen volume and total HRF area were associated with the onset of the first persistent hyperTD, multivariable analysis showed that the area of total HRF was the sole significant predictor for the onset of hyperTDs (P<0.001). ROC analysis identified an HRF area ≥ 0.07 mm² to predict the onset of persistent hyperTDs within one year with an area under the curve (AUC) of 0.661 (0.570-0.753), corresponding to a sensitivity of 55% and a specificity of 74% (P<0.001). CONCLUSIONS: The total macular burden of HRF, which includes both the HRF along the RPE and within the retina, is an important predictor of disease progression from iAMD to the onset of persistent hyperTDs and should serve as a key OCT biomarker to select iAMD patients at high-risk for disease progression in future clinical trials.

5.
Indian J Otolaryngol Head Neck Surg ; 76(3): 2820-2823, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38883473

RESUMO

A case of congenital hemifacial hypertrophy is described. This rare condition is more prevalent in males, and it is characterized by facial asymmetry. Sometimes, Hemifacial hypertrophy can lead to obstruction of the respiratory airway which may prove lethal. Here we made an attempt to present a complicated female case of true congenital hemifacial hypertrophy with its clinical, radiological presentation and surgical treatment. No single theory for hemifacial hypertrophy explains the etiology adequately. A 19-month-old female child was referred to our hospital with difficulty in breathing. She had Hemifacial hypertrophy presents with neck swelling, enlarged ear pinna with hyperpigmentation, and hypertrichosis. Radiological imaging was done, and it was diagnosed as congenital hemifacial hypertrophy. A mass obstructing the oropharynx with tonsillar enlargement was noted. Transoral endoscopic coablator-assisted excision of the oropharyngeal mass with tonsillar excision was done and the airway was secured. The neck fatty mass was excised externally. Follow-up was done for two years. Congenital Hemifacial hypertrophy is a rare congenital condition and has a good prognosis. Generally, Hemifacial hypertrophy presents with neck swelling, enlarged ear pinna with hyperpigmentation, and hypertrichosis. sometimes when presented with respiratory obstruction it can prove fatal which can be managed by securing the airway immediately. Here this case was managed with endoscopic surgical excision of obstruction and no further complications were noted. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-024-04525-x.

6.
Nanotechnology ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38901412

RESUMO

Hyperpigmentation is a skin disorder characterized by excessive production of melanin in the skin and includes dyschromias such as post-inflammatory hyperchromias, lentigens, melasma and chloasma. Topical products containing depigmenting agents offer a less aggressive treatment option for hyperpigmentation compared to methods like chemical peels and laser sessions. However, some of these agents can cause side effects such as redness and skin irritation. Encapsulating these actives in nanosystems shows promise in mitigating these effects and improving product safety and efficacy. In addition, nanocarriers have the ability to penetrate the skin, potentially allowing for targeted delivery of actives to the affected areas. The most commonly investigated nanosystems are nanoemulsions, vesicular nanosystems and nanoparticles, in which different materials can be used to generate different compositions in order to improve the properties of these nanocarriers. Nanocarriers have already been widely explored, but it is necessary to understand the evolution of these technologies when applied to the treatment of skin hyperchromias. Therefore, this literature review aims to present the state of the art over the last 15 years on the use of nanosystems as a potential strategy for encapsulating depigmenting actives for potential application in cosmetic products for skin hyperchromia. By providing a comprehensive overview of the latest research findings and technological advances, this article can contribute to improving the care and quality of life of people affected by this skin condition.

7.
Cureus ; 16(5): e59565, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38826967

RESUMO

Terra firma-forme dermatosis is an acquired and idiopathic disorder with an underestimated incidence. It is characterized by brownish skin pigmentation, forming asymptomatic plaques that give a soiled skin appearance. Soap and water have a minor effect; however, friction with 70% ethyl or isopropyl alcohol immediately eliminates plaques to a normal skin appearance, thus being the ideal method for diagnosis and treatment. The lack of familiarity with this disease possibly contributes to an alarming underdiagnosis. In this report, the authors present a case of terra firma-forme occurring in a 14-year-old Mexican patient who presented with a heart-shaped pigmented lesion in the pubic area.

8.
J Family Med Prim Care ; 13(4): 1563-1565, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38827700

RESUMO

This case report explores a rare manifestation of Becker's nevus, where the patient exhibited an unusual dermatomal distribution featuring a hyperpigmented, irregular patch with associated hypertrichosis on the T4 segment. While Becker's nevus is a well-known dermatological condition typically observed in the upper back region, instances of dermatomal distribution are exceptionally uncommon. This case presents a unique occurrence of segmental Becker's nevus, highlighting the atypical presentation of this condition.

10.
11.
Skin Res Technol ; 30(6): e13793, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38899793

RESUMO

BACKGROUND: To evaluate the efficacy and safety of stromal vascular fraction (SVF), platelet rich plasma (PRP), and 1064-nm Q-switched Nd:YAG laser in reducing nanofat treated dark circles and wrinkles under the eyes. METHOD: This study was a single-blinded randomized clinical trial conducted on patients with suborbital darkening under the eyes that randomly divided into control and case groups. In the control group, 15 patients were treated with one session of nanofat injection only, and five patients of each intervention groups received one session of nanofat+SVF injection, nanofat+PRP injection, and nanofat injection+Nd:YAG laser, respectively. Assessments methods were (1) evaluation of the degree of darkness and repair under the eyes by a blinded dermatologist based on clinical photographs, (2) investigating patient satisfaction, (3) using biometric variables for color, thickness, and density of the skin (only 3 months after the treatment), and (4) recording the possible adverse effects. CONCLUSION: In terms of the extent of reduction in the intensity of darkness under the eyes, the combined treatment of nanofat injection together with SVF, PRP, and Nd:YAG laser had a much greater therapeutic effect than nanofat injection alone. In all three groups of combined treatments, patients were 100% satisfied. In terms of biometric variables, amount of changes in colorimeter, complete and dermal thickness, complete and dermal density, between the different groups was statistically significant. The use of combined treatments including nanofat with SVF injection, PRP, and 1064 Q-switched Nd:YAG laser may be more effective than nanofat alone, in reducing infraorbital dark circles and wrinkles.


Assuntos
Técnicas Cosméticas , Lasers de Estado Sólido , Plasma Rico em Plaquetas , Envelhecimento da Pele , Humanos , Feminino , Lasers de Estado Sólido/uso terapêutico , Pessoa de Meia-Idade , Método Simples-Cego , Adulto , Técnicas Cosméticas/instrumentação , Resultado do Tratamento , Masculino , Satisfação do Paciente
12.
Artigo em Inglês | MEDLINE | ID: mdl-38912718

RESUMO

17α­hydroxylase/17,20­lyase deficiency (17OHD) is a rare form of congenital adrenal hyperplasia that causes decreased cortisol and sex steroid levels and leads to high production of adrenocorticotropic hormone (ACTH). Although affected patients have absolute cortisol deficiency, they do not show clinical signs of cortisol deficiency or hyperpigmentation. These patients most commonly present with delayed puberty and amenorrhea at late pubertal age. Impaired production of sex steroids leads to ambiguous or female external genitalia in affected 46, XY individuals. In this report, we describe a patient with 17OHD who presented with hyperpigmentation and hypergonodotropic hypogonadism while receiving chemotherapy.

13.
Eur J Dermatol ; 34(2): 139-143, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38907543

RESUMO

Diffuse hyperpigmentation with guttate hypopigmentation (DHGH) is a new acquired pigmentary disorder. Only a few cases have previously been reported in the Chinese population, in Chinese. To summarise the clinical, dermoscopic, and histopathological findings of DHGH in the English literature, to improve the recognition and management of this condition. This was a retrospective study to summarise the clinical, dermoscopic, and pathological findings of nine cases of DHGH. All nine patients with DHGH were female. The age at onset varied from 6 to 24 years (median 17 years). Patients were generally in good health without systemic disease. The lesions were often generalised to the trunk and extremities without any discomfort. Typical lesions were characterised by multiple uniform hypopigmented spots, 2-5 mm in diameter, irregularly distributed over diffuse hyperpigmentation. Dermoscopy revealed multiple blurred patchy areas of brownish pigmentation, sparse linear and dotted vessels, and perifollicular pigmentation on a white to bright white background, surrounded by brown hyperpigmentation. Histopathological findings included mild abnormal pigment of the epidermis, focal vacuolar degeneration of the basal cells, mild pigment incontinence and perivascular lymphocytic infiltration in the dermis. DHGH is a new entity with distinctive clinical manifestations that differ from those of other known pigmentary disorders. So far, DHGH has only been reported in the Chinese population. It may not be uncommon and has not received much attention due to the few reports. The aetiology and pathogenesis of DHGH are still unknown and require further investigation.


Assuntos
Hiperpigmentação , Hipopigmentação , Humanos , Feminino , Hiperpigmentação/patologia , Hipopigmentação/patologia , Estudos Retrospectivos , Adolescente , Adulto Jovem , Criança , Dermoscopia , Adulto
14.
Bioorg Chem ; 150: 107533, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38878750

RESUMO

Hyperpigmentation disorders may result from inappropriate melanin deposition and/or excessive melanin synthesis. They are classified mainly as aesthetic problems, but they can significantly affect human health by decreasing self-esteem. There are available only limited treatment options for hyperpigmentation disorder, among others, cosmetic products applied topically. Depigmenting ingredients were found to be ineffective and characterized by various side effects. As a result, many efforts are made to discover novel, potent, and safe melanogenesis inhibitors for possible use in topical cosmetic depigmenting formulations. Cinnamic acid derivatives constitute a widely tested group for that purpose. This article reports research in the group of N-alkyl cinnamamide derivatives (un)substituted in phenyl ring. Among tested series, (E)-3-(4-chlorophenyl)-N-(5-hydroxypentyl)acrylamide (compound 21) showed the most promising inhibitory properties in mushroom tyrosinase assay (IC50 = 36.98 ± 1.07 µM for monophenolase activity, IC50 = 146.71 ± 16.82 µM for diphenolase activity) and melanin production inhibition in B16F10 mouse melanoma cell line at concentration 6.25 µM resulting probably from decreasing of Tyr, Mitf, Tyrp-1, and Tyrp-2 genes expression. This compound also showed melanin production inhibitory properties in pigmented reconstructed human epidermis when used in 1 % and 2 % solutions in 50 % PEG400. In vitro evaluation of its safety profile showed no cytotoxicity to human keratinocytes HaCaT, human skin fibroblasts BJ, and human primary epidermal melanocytes HEMa, no mutagenicity in the Ames test, no genotoxicity in micronucleus test, no phototoxicity, as well as no skin irritation potential tested in PEG400 solution. This compound was also shown to penetrate across the epidermis to reach the possible site of action. The performed research led to classify (E)-3-(4-chlorophenyl)-N-(5-hydroxypentyl)acrylamide as a novel potential depigmenting cosmetic ingredient.

15.
Antioxidants (Basel) ; 13(6)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38929064

RESUMO

The excessive production of melanin can cause skin diseases and hyperpigmentation. In this study, resveratrol contained in Dongjin rice seed (DJ526) was increased through callus induction. The antioxidant capacity of resveratrol-enriched rice callus was evaluated using the ABTS radical scavenging method and was equivalent to that of vitamin C. DJ526 rice callus extract significantly increased antioxidant activities in a concentration-dependent manner. The anti-melanogenesis effects of DJ526 rice callus extract were also evaluated in melan-a cells. Resveratrol-enriched rice callus extract significantly (i) decreased the size and number of melanin-containing cells, (ii) suppressed the activity of cellular tyrosinase and melanin content, (iii) downregulated the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, (iv) increased the expression of phosphorylated extracellular signal-regulated kinase 1/2 and protein kinase B, and (v) inhibited the activation of phosphorylated p38 in melan-a cells. From the above observations, DJ526 rice callus extract showed strong antioxidant and anti-melanogenesis activity at the concentration test. These findings indicate the potential of resveratrol-enriched rice callus as a novel agent for controlling hyperpigmentation.

16.
Arch Dermatol Res ; 316(6): 215, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38787426

RESUMO

Serpentine supravenous hyperpigmentation (SSH) describes increased skin pigmentation that develops in the area immediately overlying the vessels through which chemotherapeutic drugs are administered. While SSH can be cosmetically distressing and there are no definitive management options, the literature is severely limited and the variations in clinical presentation, risk factors, and histopathology of SSH across patients are not well understood. We aimed to systematically summarize characteristics from current available data, and thus improve SSH awareness and management. A literature search was conducted in PubMed using specific eligibility criteria through the end of December 2022. Included articles focused on patients who experienced SSH after chemotherapy infusion. Study quality was assessed using a modified Oxford Centre for Evidence-Based Medicine quality rating scheme. Of the 41 articles identified by literature search, 24 met eligibility criteria. Two additional articles were identified through the reference sections of retrieved articles, for 26 articles total. All articles were case reports, representing 28 patients total. Locations of SSH were mostly in the forearm near the site of injection (85%), and the most common associated symptom was erythema. Histopathologic analysis was available for half of cases, the majority of which were inflammatory in nature. The most common inflammatory pattern observed was a vacuolar/lichenoid interface dermatitis. Duration of SSH ranged from days to > 1 year after the chemotherapy was stopped. Six (21%) patients were managed with topical steroids and oral vasodilators, six (21%) patients switched to central venous infusion rather than peripheral infusion, five (18%) patients received only supportive care, three (11%) patients received venous washing with chemotherapy, three (11%) patients stopped chemotherapy, and one (4%) patient reduced the chemotherapy dosage. Ten (36%) patients attained complete resolution, seven (25%) had SSH that was near resolution/fading, and three (11%) had persistent hyperpigmentation. Although SSH often spontaneously resolves once the chemotherapeutic agent is stopped, it can persist in some patients and cause significant distress. As the literature is severely limited and there are no definitive treatments, additional research using more standardized definitions and methods of assessments is necessary to improve characterization of SSH and evaluate potential interventions.


Assuntos
Antineoplásicos , Hiperpigmentação , Humanos , Hiperpigmentação/induzido quimicamente , Hiperpigmentação/diagnóstico , Antineoplásicos/efeitos adversos , Pigmentação da Pele/efeitos dos fármacos , Pele/patologia , Pele/efeitos dos fármacos , Eritema/induzido quimicamente , Eritema/diagnóstico
17.
Arch Dermatol Res ; 316(6): 253, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38795157

RESUMO

Dyschromia is a top diagnosis among African Americans (AA). Sunscreen is an essential part of its management, but AA have low sunscreen use. We sought to examine the perception of sunscreen utility in dyschromia and photoaging among patients who identify as AA or Black. This cross-sectional study recruited participants from the Case Western Reserve University Academic Dental Clinic. Participants completed an electronic survey that contained questions related to sunscreen use, knowledge of the sun's role in hyperpigmentation and photoaging, and whether sunscreen could be used for hyperpigmentation and photoaging. Of the 151 participants recruited, 63.6% (n = 96) were women and 36.4% (n = 57) were men. Consistent with previous reports, participants had lower sunscreen use (20.5%) than whites (43.5%). The majority of participants (80.1% and 58.3%, respectively) didn't attribute the sun to hyperpigmentation or photoaging. Participants with dark/brown spots were significantly more likely to not attribute the sun to hyperpigmentation than those without spots. (p = 0.003) Limitations for this study include its small sample size, recall and reporter bias, question misinterpretation, and lack of question neutrality. This study highlights the knowledge gap of a major contributing factor to dyschromia which in turn could be leading to their view of the decreased utility of sunscreen.


Assuntos
Negro ou Afro-Americano , Conhecimentos, Atitudes e Prática em Saúde , Protetores Solares , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Negro ou Afro-Americano/estatística & dados numéricos , Negro ou Afro-Americano/psicologia , Estudos Transversais , Hiperpigmentação/prevenção & controle , Envelhecimento da Pele/efeitos dos fármacos , Pigmentação da Pele/efeitos dos fármacos , Luz Solar/efeitos adversos , Protetores Solares/administração & dosagem , Inquéritos e Questionários/estatística & dados numéricos
18.
Clin Plast Surg ; 51(3): 409-418, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38789150

RESUMO

Scars commonly give rise to unpredictable, potentially irritating, cutaneous complications including pruritis, folliculitis, and pigment changes. These problems can be self-limiting and are prevalent in many burn cases, although their expression varies among individuals. A better understanding of the presentation, risk factors, and pathophysiology of these long-term sequelae allows for more comprehensive care of burn survivors.


Assuntos
Queimaduras , Transplante de Pele , Humanos , Queimaduras/cirurgia , Queimaduras/complicações , Queimaduras/terapia , Cicatriz/etiologia , Cicatriz/cirurgia , Foliculite/etiologia , Foliculite/terapia , Transtornos da Pigmentação/etiologia , Transtornos da Pigmentação/terapia , Transtornos da Pigmentação/cirurgia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/terapia , Prurido/etiologia , Prurido/terapia , Transplante de Pele/efeitos adversos , Transplante de Pele/métodos
19.
J Pharm Biomed Anal ; 246: 116223, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38763108

RESUMO

The utilization of Hydroquinone (HQ) in over-the-counter skincare items is subject to restrictions. Consequently, Arbutin (AR) serves as a reliable alternative for addressing hyperpigmentation in non-prescription topical formulations. Nevertheless, AR undergoes decomposition into HQ and p-Benzoquinone (BZ) when exposed to temperature stress, ultraviolet light, or dilution in an acidic environment, all of which can induce skin toxicity. The intention of this paper is to investigate the effect of extraction procedure on the conversion of AR to HQ and or BZ and to evaluate kinetics of AR hydrolysis to HQ. Meanwhile this study aims to evaluate AR and BZ interference with the United States Pharmacopoeia (USP) identification and assessment method for HQ Hydrolytic stress during extraction conditions underwent optimization through systematic screening tests. Subsequent assessment of the residual drug and its degradation products were achieved by HPLC method. The resulting data were meticulously fitted to various kinetic models. To analyze the potential interference of AR in HQ measurement using USP method, the standard concentrations of AR and HQ were analyzed through UV-VIS spectrophotometry. For enhanced certainty, a validated HPLC method analysis was also conducted. Notably, the acid hydrolysis of AR exhibited independence from its initial concentration. So, the hydrolytic degradation of AR exhibited a Zero-order kinetic profile. Furthermore, the proven interference of AR in the UV-VIS spectrophotometry method was identified within the context of the USP method. This study successfully utilized an adopted HPLC method for the concurrent quantification of AR, HQ, and BZ. The potential interference of AR in the UV-VIS spectrophotometric assay for HQ may lead to false results especially for regulatory purposes.


Assuntos
Arbutina , Benzoquinonas , Hidroquinonas , Hiperpigmentação , Arbutina/análise , Arbutina/química , Hidroquinonas/análise , Hidroquinonas/química , Benzoquinonas/química , Benzoquinonas/análise , Cromatografia Líquida de Alta Pressão/métodos , Hidrólise , Preparações Clareadoras de Pele/química , Preparações Clareadoras de Pele/análise , Cinética , Administração Tópica , Espectrofotometria Ultravioleta/métodos
20.
Chem Biol Drug Des ; 103(5): e14539, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38760181

RESUMO

Tyrosinase is a copper-containing enzyme involved in the biosynthesis of melanin pigment. While the excess production of melanin causes hyperpigmentation of human skin, hypopigmentation results in medical conditions like vitiligo. Tyrosinase inhibitors could be used as efficient skin whitening agents and tyrosinase agonists could be used for enhanced melanin synthesis and skin protection from UV exposure. Among a wide range of tyrosinase-regulating compounds, natural and synthetic derivatives of furochromenones, such as 8-methoxypsoralen (8-MOP), are known to both activate and inhibit tyrosinase. We recently reported a synthetic approach to generate a variety of dihydrofuro[3,2-c]chromenones and furo[3,2-c]chromenones in a metal-free condition. In the present study, we investigated these compounds for their potential as antagonists or agonists of tyrosinase. Using fungal tyrosinase-based in vitro biochemical assay, we obtained one compound (3k) which could inhibit tyrosinase activity, and the other compound (4f) that stimulated tyrosinase activity. The kinetic studies revealed that compound 3k caused 'mixed' type tyrosinase inhibition and 4f stimulated the catalytic efficiency. Studying the mechanisms of these compounds may provide a basis for the development of new effective tyrosinase inhibitors or activators.


Assuntos
Inibidores Enzimáticos , Monofenol Mono-Oxigenase , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/síntese química , Cinética , Humanos , Metoxaleno/farmacologia , Metoxaleno/química , Ativadores de Enzimas/química , Ativadores de Enzimas/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...