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Biomedical subjects

Juan Pablo Castanedo-Cazares

Publications and source records attributed to Juan Pablo Castanedo-Cazares.

14 recordsLinked to original sources
PubMed2004

A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma.

BACKGROUND: Melasma is an acquired treatment-resistant hyperpigmentation of the skin. METHODS: Sixteen women with idiopathic melasma were included in our trial. After randomization by another clinician, they were instructed to use, at night, 5% ascorbic acid cream on one side of the face and 4% hydroquinone cream on the other side, for 16 weeks. Sunscreen was applied daily throughout the period of observation. They were evaluated every month by colorimetry, digital photography, and regular color slides. Subjective evaluation by each patient was also taken into account. RESULTS: The best subjective improvement was observed on the hydroquinone side with 93% good and excellent results, compared with 62.5% on the ascorbic acid side (P < 0.05); however, colorimetric measures showed no statistical differences. Side-effects were present in 68.7% (11/16) with hydroquinone vs. 6.2% (1/16) with ascorbic acid. CONCLUSION: Although hydroquinone showed a better response, ascorbic acid may play a role in the therapy of melasma as it is almost devoid of side-effects; it could be used alone or in combination therapy.

Administration, Topical↗
PubMed2004

Pentoxifylline in the treatment of actinic prurigo. A preliminary report of 10 patients.

BACKGROUND: Actinic prurigo (AP) is a chronic familial photodermatosis usually seen in Latin-American Mestizo and Indian populations. It frequently begins in childhood and is more prevalent in females. The pathogenesis of AP has not been clearly elucidated, but previous studies have suggested an immune-mediated condition. Many drugs have been employed to treat AP patients with variable success. OBJECTIVE: To assess the clinical efficacy of pentoxifylline (PTX) in the treatment of AP patients by measuring its effects on lesions and pruritus. METHODS: 10 patients with severe AP were included to receive PTX in a 6-month open-label uncontrolled study. RESULTS: Clinical improvement of lesions was evident in all patients. Relief in pruritus was evident after 1 month of treatment and was maintained while receiving PTX. Five patients were followed up for 2 years, 2 obtained complete remission, and 3 had an important reduction in the use of corticosteroids. CONCLUSION: PTX was useful in the treatment of our actinic prurigo patients. It may induce a complete or partial remission of lesions and allow a decrease in the use of topical corticosteroids.

Adult↗
PubMed2003

A double-blind randomized trial of 0.1% tacrolimus vs 0.05% clobetasol for the treatment of childhood vitiligo.

OBJECTIVE: To assess the safety and efficacy of topical 0.1% tacrolimus vs 0.05% clobetasol propionate. DESIGN: Randomized double-blind trial. SETTING: Department of Dermatology, Hospital Central Dr Ignacio Morones Prieto, San Luis Potosí, México. PARTICIPANTS: From 20 children with vitiligo, 2 symmetrical lesions of about the same size and evolution time were selected. They were devoid of any topical or systemic therapy for 2 months prior to inclusion. Interventions Treatment with topical tacrolimus and clobetasol for a 2-month period. MAIN OUTCOMES MEASURES: The grade of repigmentation was evaluated by color slides at baseline and again at every 2-week visit. The slides were analyzed by 2 clinicians unrelated to the study and by a morphometric digitalized computer program. Characteristics of pigment, time of response, symptoms, telangiectasias, and atrophy were evaluated every 2 weeks. RESULTS: Eighteen (90%) of the 20 patients experienced some repigmentation. The mean percentage of repigmentation was 49.3% for clobetasol and 41.3% for tacrolimus. Lesions in 3 patients using clobetasol presented atrophy, and 2 lesions incurred telangiectasias; tacrolimus caused a burning sensation in 2 lesions. CONCLUSIONS: Tacrolimus proved almost as effective as clobetasol propionate to restore skin color in lesions of vitiligo in children. Because it does not produce atrophy or other adverse effects, tacrolimus may be very useful for younger patients and for sensitive areas of the skin such as eyelids, and it should be considered in other skin disorders currently treated with topical steroids for prolonged periods.

Administration, Topical↗
PubMedDate not supplied

Subungual chondroblastoma in a 9-year-old girl.

Chondroblastoma is an uncommon primary bone tumor, mainly found in the epiphyses of long bones. We describe a 9-year-old girl who presented with a chondroblastoma as a subungual mass in the fifth toe. Radiographs showed an expansive, calcified tumor of the distal phalanx. Histologic examination after excision revealed chondroid differentiation, active mitosis, multinucleated giant cells, calcification, and necrosis. There was no recurrence of the lesion after surgical excision. The purpose of this report is to document this unusual event that occurred in such a short bone as the distal phalanx of the fifth toe, mimicking a dermatologic entity.

Bone Neoplasms↗
PubMedDate not supplied

[Inconsistency in sun protection factor (SPF) index in Mexico. The case of sunscreens for oily skin].

BACKGROUND: In Mexico, information regardiing sunscreen protection is not widely accessible from sources other than manufacturers. OBJECTIVE: To assess the Sun Protection Factor (SPF) of 12, over the counter sunscreens for oily or acne-prone skin available in the Mexican market. SETTING: Dermatology Department. Autonomous University of San Luis Potosí, Mexico. SUBJECTS AND METHODS: Twenty healthy volunteers ofskin type III and IV were tested. Sunscreen SPFs were measured using solar simulated radiation according to FDA final monograph. RESULTS: SPFs ranged between 7.8 and 26.9. Overall SPFs determined by solar simulator showed values between 22% to 74% less than the one advertised in their labels. CONCLUSIONS: We warn about the potenital risk of SPF overestimation as many of'the sunscreens tested did not comply with their offered protection. A proper regulation is needed because sunscreens are considered cosmetic products and do not require clinical tests to verify their efficacy before marketing.

Adult↗
PubMedDate not supplied

[Analysis of the digital unit as reference measurement for the topical prescription in Mexico].

INTRODUCTION: Topical prescription unlike other dosage forms is generally considered an inaccurate procedure. The fingertip unit (FTU) is a proposed measure for dosing a topical drug. FTU is the amount of ointment obtained from a tube with a 5 mm diameter nozzle, applied from the distal skin-crease to the tip of the index finger. OBJECTIVE: Asses FTU as a reference measure for topical prescription among the Mexican population. METHODS: The length of the II hand fingertip was recorded in 324 individuals and the weight of 1 FTU and its covering surface was registered. RESULTS: Average length of index fingertip was 24 mm (IC95 26.7-27.2) in males (n=40), and 24 mm (IC95 24.3-24.8) in females (n=50). One FTU weighed 0.45 g (IC95 0.41-0.48) in males (n=40), and 0.38 g (IC95 0.35-0.41) in females (n=50). One FTU covered 275 cm2 (IC95 255-294) in males (n=15), and 257 cm2 (IC95 200-240) in females (n=15). CONCLUSION: FTU may be a helpful measure for dosing and supervising the administration of topical medications for both patients and dermatologists in Mexico.

Administration, Topical↗
PubMedDate not supplied

[Knowledge and attitudes of Mexican population concerning solar radiation].

BACKGROUND: The effects of solar radiation in human health is dependent upon environment, behavior, and genetic characteristics. OBJECTIVE: Identify phenotypic features, attitudes, knowledge and preventive measures concerning sun exposure among a local population. METHODS: People older than 15 years were interviewed concerning time of sun exposure, photoprotection, and general knowledge about adverse effects of sun irradiation. RESULTS: 964 questionnaires were analyzed. White-skin population represented 7.4%, light-brown 24.8%, dark-brown 67.8%. Exposure time on working days was up to 15 min in 27.8%, and more than 60 min in 38.8%. On weekends, time exposure was similar. 30% did not take any preventive measures 41% wore hats and 11.8% used sunscreens. Among participants, 85.4% were aware that sun exposure caused skin cancer, 64. 1% knew that mortality is increased, 83.4% reported that excessive sun exposure is related to aging of the skin, and 26.5% believed tanning is healthy. CONCLUSIONS: In spite of thefact that a great majority of the population recognized that sun exposure produces aging and skin cancer, their exposure is widespread. This survey may be a valuable tool to design preventive public health campaigns that target high risk groups.

Adolescent↗