Madhu Pathak

Madhu Pathak
SGT University · Ayurveda

About

98
Publications
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Publications

Publications (98)
Article
In this paper, the role of reactive oxygen species in photoaging is presented. Many photosensitizing agents are known to generate reactive oxygen species (singlet oxygen (1O2), superoxide anion (O2.-) and .OH radicals). Although photoaging (dermatoheliosis) of human skin is caused by UVB and UVA radiation, the hypothesis tested here in the pathogen...
Article
Clinical and experimental evidence explaining and supporting the role of UV radiation as a causal factor for the induction and promotion of nonmelanoma and malignant melanoma skin cancer are presented. While there is excellent animal experimental data and human epidemiologic evidence supporting the causal relationship of UVR (UVB, as well as UVA ra...
Article
An estimated 400,000 non-melanoma skin cancers occur each year. A majority of them will develop on sun-exposed areas of the face, head, and neck. By virtue of having assignments that involve outdoor duty, often in areas of high ultraviolet radiation exposure, military personnel are at increased risk of developing these cancers. Hats provide a means...
Article
This study was directed to examine the role of type II (photodynamic) reactions involving the production of reactive oxygen species (singlet oxygen, superoxide anion, and hydroxy radicals) in in vitro and in vivo photosensitization reactions induced by skin photosensitizing chemicals. Several porphyrins and psoralens, as model compounds representin...
Article
Superoxide dismutase provides a protective defense mechanism in cellular compartments against the potential cytotoxicity of superoxide anion generated by ultraviolet radiation. Little information is available about the nature of superoxide dismutase in mammalian skin. We report the isolation and characterization of superoxide dismutase from human,...
Chapter
Natural light and UV radiation (UVR) from artificial sources has always been recognized for and endowed with health-giving powers as well as for its tonic value of generating a feeling that it is good for our psyche and contributes to the synthesis of vitamin D essential for maintaining calcium and phosphorus homeostasis and a healthy skeleton. It...
Chapter
The herbal use of psoralens (furocoumarins) for the treatment of leukoderma (vitiligo) in India, Egypt, and many other far Eastern countries dates back to the time before the birth of Christ. The roots of psoralen therapy for vitiligo can be traced as far back as 1,500 B.C. in Atharva Veda in which the early Ayurvedic therapy practiced by ancient H...
Article
In this brief review, clinically relevant practical aspects of topical protection against the harmful effects of solar radiation on human skin are discussed. The article covers information in the following areas of photo-protection: nature of solar radiation; classification of normal individuals into sun-reactive skin types I-VI; minimal erythema d...
Article
The visible cutaneous pigmentary response to ultraviolet-A (UVA) is immediate and, following sufficient exposure, may persist, whereas ultraviolet-B (UVB)-induced pigmentation appears after a delay of several days. We compared the in vivo response of melanocytes to single and multiple exposures of narrow band UVA and UVB irradiation which produced...
Article
DNA repair in murine and guinea pig skin has been studied by the immunohistochemical method. For the detection of DNA photolesions in situ by the indirect immunofluorescence (IF) method two antisera directed against DNA-pyrimidine-dimers and DNA-psoralen-photoadducts have been applied. The IF assay enabled to detect the DNA photodamage induced by h...
Article
The role of reactive oxygen (1O2 and O2-.) in skin photosensitization and tanning reaction has been examined. Riboflavin (RF), hematoporphyrin (HP), 3-carbethoxypsoralen (3-CP), and 8-methoxypsoralen (8-MOP), upon photoexcitation under aerobic conditions, produced singlet O2 (1O2). RF, 3-CP, and 8-MOP also produced superoxide anion (O2-.). Reactive...
Article
Melasma is a circumscribed brown macular hypermelanosis of the areas of the face and neck that are exposed to light. Clinical trials with various depigmenting formulations containing hydroquinone were conducted to determine the ideal concentration of hydroquinone, retinoic acid, and corticosteroids for the treatment of melasma. The compounds were t...
Article
Plants are nature's most efficient factories for producing a variety of chemicals. Of the more than half million known plant species, only about 12,000 have been investigated, with isolation and identification of about 11,000 naturally occurring compounds. 1,2 Most plant species are considered harmless, and only about 500 are reported to be harmful...
Article
An immunofluorescence (IF) method for the detection of 8-methoxypsoralen (8-MOP) photoadducts to DNA has been developed to assess nuclear damage in keratinocytes and melanocytes after psoralen plus UVA (PUVA) treatment, both under in vitro and in vivo conditions. Cryostat sections of the albino and pigmented guinea pig and human skin were used for...
Article
In the past five years, it has been reported that certain dicarboxylic acids (C8-C13) and azelaic acid (C9) (AZA), in particular, have a remarkable effect in the management of lentigo maligna, human malignant melanoma, and certain disorders of hyperpigmentation. Preclinical trials, therefore, were undertaken in order to evaluate the effectiveness o...
Article
The widespread introduction of commercially availabe high-intensity ultraviolet A (UVA) suntanning units does pose potential acute (short-term) and chronic (long-term) hazards to the skin and the eyes. Specifically, immunologic, degenerative, and neoplastic alterations of the skin, as well as cataracts and retinal damage to the eye, have each been...
Article
In this paper, we report on 366 East Indian patients with vitiligo who were treated for 2 to 3 years with either 8-methoxypsoralen (8-MOP), 4,5',8-trimethylpsoralen (TMP), or psoralen and sunlight. These patients with amelanotic macules had 10 to 70% skin involvement of 1 to 50 years duration. Male and female patients from ages 12 to 70 years were...
Article
Vitiligo is refractory to most therapeutic modalities. To assess the efficacy of a variety of PUVA therapies, we enrolled 596 subjects in a prospective study, and 230 were followed for up to 55 months. Various psoralen derivatives and dosage schedules were used. Each subject was examined at yearly intervals for therapeutic response and evidence of...
Article
We initiated these studies to determine whether bifunctional (interstrand cross-linking) psoralens, such as 8-methoxypsoralen (8-MOP), are more carcinogenic than are the monofunctional, such as angelicin or isopsoralen derivatives, and 3-carbethoxysporalen (3-CP). Hairless mice (Skh:hr-1) in groups of 40 were treated three times weekly for 12 to 15...
Article
Psoralens, tricyclic furocoumarins with potent photosensitizing properties in the skin, are now widely used in the treatment of several dermatologic diseases. In this study, the metabolism of 4,5',8-trimethylpsoralen (TMP) and 8-methoxypsoralen (8-MOP) was studied in mouse liver. Orally administered TMP is transformed into several metabolites, the...
Article
Furocoumarins (psoralens) are potent skin photosensitizing agents that are used in combination with long-wavelength ultraviolet radiation (320-400 nm) in the treatment of psoriasis and other skin diseases. Twelve linear and angular psoralens, capable of forming monofunctional and bifunctional adducts with DNA, were examined with a view to elucidate...
Article
Crude coal tar (CCT) and certain photoreactive ingredients of CCT are photosensitizing agents used in the treatment of skin diseases (psoriasis, atopic eczema, etc.). Limited information is available in elucidating the mode of action of CCT in clearing psoriasis or causing skin photosensitization reactions. The production of singlet oxygen (1O2) an...
Article
The molecular basis for the clinically observed differences in the skin photosensitizing activity and therapeutic effectiveness of the topically applied and orally administered drug trimethylpsoralen (TMP) was investigated. TMP, when tested topically, is a very potent photosensitizing and therapeutically effective furocoumarin in the treatment of p...
Article
7-Methyl- (1 a) and 4,7-dimethylallopsoralen (1 b), prepared about ten years ago and till now considered non-photosensitizing agents, have been re-investigated for studying their photochemical and photobiological properties. They form a molecular complex with DNA in the ground state, undergoing intercalation between two base pairs of the macromolec...
Article
Reusable ultraviolet dosimetry badges have been developed that provide a visual indication of daily cumulative ultraviolet (UV) exposure. These two-sided, tapelike devices measure UV radiation emitted by sunlight or an artificial UV light source exposure by means of a photochromic aziridine color change reaction that is UV-integrating but optically...
Article
A randomized double-blind clinical trial involving twenty-two volunteers was conducted in two locations (Orlando, FL, and St. Paul, MN) to test the efficacy of the newly designed ultraviolet monitor badges (Sun Timers), described in another paper by us in this issue of the Journal, 1 and to establish the relationship between spectral band exposure...
Article
The basic aspects of cutaneous photosensitization reactions and the mode of therapeutic effectiveness of psoralens and coal tar, the two groups of photosensitizing agents used extensively in the photochemotherapy of psoriasis, have been reviewed. Psoralen-induced skin photosensitization and the therapeutic action of psoralens involve two distinct t...
Article
We have investigated a series of linear and angular furocoumarins, capable of forming either the monofunctional adducts (single strand) or bifunctional adducts (interstrand cross-links) with DNA with a view to examine the relationship of their skin photosensitizing potency, their ability to produce singlet oxygen (1O2) or superoxide radicals (O-.2...
Article
Psoralens are tricyclic furocoumarins with potent photosensitizing properties in the skin and are now widely used in the treatment of several dermatologic diseases. In this study the effect of 3 different psoralens 8-methoxypsoralen (8-MOP), 4,5',8-trimethylpsoralen (TMP) and isopsoralen on hepatic microsomal drug-metabolizing enzymes and cytochrom...
Article
This review deals with topical and systemic approaches for protection of human skin against the harmful effects of solar radiation. Two concerns about the deleterious effects of sun exposure involve: (1) acute effects (e.g., sunburn and drug-induced phototoxicity) and (2) potential long-term risks of repeated sun exposures leading to development of...
Article
Variegate porphyria (VP) is an autosomal dominant disease characterized in adults by mechanical fragility and blistering of sun-exposed skin or acute visceral and neurological manifestations. The laboratory diagnosis of VP depends on a search for high levels of coproporphyrin and protoporphyrin in the feces. Variegate porphyria has been infrequentl...
Article
Circumscribed dermal hypermelanosis refers to a group of cutaneous disorders with circumscribed blue, blue-grey, slate-grey, or blue-black pigmentation. Dermal Melanocyte deposition (melanocytosis) and melanin in mdcrophages (melaninosis) are observed histopathologically. This group of disorders can be differentiated clinically from brown epidermal...
Chapter
Why is photoprotection of importance to humans? We must be in the light; we cannot be forced to work or live in the dark. The sun is necessary to sustain all life on earth. We are warmed by its rays, and we are able to see with eyes that respond to that portion of the solar spectrum known as visible light. Our skin and blood vessels respond to the...
Chapter
While phototherapy is defined as the application of visible or ultraviolet (UV) radiation to the treatment of disease, in photochemotherapy a chemical sensitizer is administered concurrently and the therapeutic effect depends on photochemical interaction of the chemical and radiation. In the doses used, chemical and radiation alone usually have lit...
Article
To have, before the clinical evaluation, sufficiently predictive information about the antiproliferative and phototoxic effect of new potential agents for the photochemotherapy of psoriasis some simple tests have been worked out. The antiproliferative activity was evaluated studying the inhibition of DNA synthesis first in Ehrlich ascites tumor cel...
Article
Melasma is an acquired brown hypermelanosis of the face. Although it is thought that melasma is associated with multiple etiologic factors (pregnancy, genetic, racial, and endocrine), one of the primary causes of its exacerbation appears to be exposure to sunlight. Three patterns of melasma are recognized clinically: (1) a centrofacial pattern, (2)...
Article
Photobinding to DNA and cross-linking formation in vitro, as well as the skin photosensitizing activity on guinea pigs of two water-soluble derivatives of psoralen (5 and 8-diethylaminopropyloxypsoralen hydrochloride) have been studied. For purposes of comparison, the results have been correlated with those obtained, in the same experimental condit...
Article
Full-text available
The complement system was analysed in 14 asymptomatic patients with erythropoietic protoporphyria. In the majority of the sera studied the levels of complement components C1, C4, C2, and C3 were within the normal range. Upon ultraviolet light (330--460 nm) irradiation of the serum samples in vitro, a marked decrease in total hemolytic activity acco...
Article
To the Editor.— Attempts have been made by several groups to assess the photosensitivity of patients with erythropoietic protoporphyria (EPP) by an objective method, ie, phototesting with monochromatic light at several discrete wavelengths. However, many patients have failed to respond at all to this kind of light exposure. We have had more consis...
Article
A review is given of the nomenclature, the biochemical aspects, the clinical aspects, differential diagnosis, environmental factors, the role of liver tumor, the photobiologen and the treatment of porphyria cutanea tarda.
Article
Four groups of female Dutch-belted rabbits (Oryctulagus cuniculus) were given methoxsalen (12 mg/kg) or placebo by oral intubation and 1 hr later were exposed to UVA for either 2 or 8 hr. This procedure was repeated 5 days each week for 18 mo. A fifth group received no drug and no UVA exposure. The skin of the animals given methoxsalen and UVA show...
Article
Recently a major metabolite of 4,5',8-trimethylpsoralen (TMeP) (a photochemotherapeutic agent), was isolated from the urine of mice and human volunteers receiving the drug orally; it was identified as 4,8-dimethyl-5'-carboxypsoralen. The synthesis of this compound has been carried out to obtain a distinct confirmation of the structure of the urinar...
Article
In recent years, psoralens have been widely-used clinically, but until now their in vitro and in vivo metabolic reactions have not been studied. The photochemotherapeutic agent 4,5',8-trimethyl-psoralen (TMeP) is readily metabolized in vitro by mouse liver under mixed-function oxidase conditions, with formation of three products. One of the product...
Article
8-methoxypsoralen, the most widely used psoralen in photochemotherapy, was shown to induce mixed-function oxidases. Induction of mixed-function oxidases in mouse liver was examined after mice were given a single dose of one of three psoralens. 8-methoxypsoralen clearly induced p-nitroanisole O-demethylase and slightly induced aryl hydrocarbon hydro...
Article
We treated with high doses of oral beta carotene (Solatene) (15 to 180 mg/day) 133 patients suffering from erythropoietic protoporphyria (EPP), 27 patients with polymorphous light eruption, six patients with solar urticaria, three patients with hydroa aestivale, one patient with porphyria cutanea tarda, and two patients with actinic reticuloid to r...
Chapter
A large number of drugs are known to interact strongly with nucleic acids (e.g., several antitumoral agents such as actinomycin-D, adriamycin, and daunomycin, and drugs such as chloroquin, quinacrine, miracil D, ethidium bromide, etc). Many of these drugs show specific, non-photochemical binding to double-stranded nucleic acids through intercalatio...
Article
A new light source that provides high-intensity ultraviolet light (UVA) (300 to 400 nm) to the entire body surface makes orally administered psoralen treatment of vitilligo with an artificial light practical. In the 26 patients studied, the degree of repigmentation with either trioxsalen (TMP) or methoxsalen (8-MOP) and high intensity UVA was at le...
Article
The effects of pulsed nitrogen gas laser emission (337.1 nm wavelength) were studied on human skin. The laser provides high-intensity monochromatic UVA radiation and can elicit delayed erythema in an actual exposure time of about 1 msec (105,000 pulses, each lasting 10 nsec, delivered over 210 sec). The effects of nitrogen laser irradiation were co...
Article
A considerable amount of evidence exists in support of the role of ultraviolet radiation as a major etiologic factor in human skin cancer, both melanoma and carcinoma types. On the basis of epidemiologic studies a phenotype has been described which helps to identify the persons who are more susceptible to skin cancer. In an attempt to further defin...
Article
Photochemotherapy denotes a therapeutic approach that is based on the interaction of light and a photoactive drug. This study describes the efficacy of photochemotherapy, using orally administered methoxsalen and long-wave ultraviolet light in 91 patients with severe, generalized psoriasis. Oral administration of methoxsalen was followed by exposur...
Chapter
When viewed from the perspective of photobiology, melanin pigmentation of human skin can be described in two categories: the first, constitutive or intrinsic skin color, and the second, facultative or inducible skin color (Quevedo et al., 1974). Constitutive skin color designates the genetically determined levels of cutaneous melanin pigmentation i...
Article
The major source of color in human skin derives from the presence within the epidermis of specialized melanin-bearing organelles, the melanosomes. Tanning of human skin on exposure to ultraviolet light results from increased amounts of melanin within the epidermis. Melanosomes synthesized by melanocytes are acquired by keratinocytes and transported...
Article
Phytoene, the colorless triene precursor of β carotene (17 mg/g body weight) or a placebo was given to guinea pigs by daily i.p. injection for 14 days, after which the animals were exposed to radiation (>280 nm). It was found that the animals receiving phytoene developed significantly less erythema to the radiation than did the animals receiving pl...
Article
The photoxicity of coal tars was determined by comparing the ultraviolet light (UVL) energy required to produce erythema at tar treated sites (minimal phototoxic dose [MPD]) with the energy required to produce the same degree of erythema at untreated control sites (minimal erythema dose [MED]). The ratio of MED/MPD is the photoxic index (PI). Tars...
Article
To the Editor.— In the April 1974 issue of the Archives, Drs. Stern and Kihiczak reported the results of their attempts to determine the action spectrum of ultraviolet light-induced clearing of psoriasis (109:502, 1974). Using a xenon arc solar simulator and a cold quartz lamp, the authors compared the clearing of psoriatic plaques that occurred a...
Article
Carotenoid pigments were extracted chemically from both epidermis and dermis obtained from non-carotenemic individuals at autopsy. Absorption maxima characteristic of beta-carotene were found in the extracts of specimens of epidermis following cantharidin application in volunteers made carotenemic by the ingestion of beta-carotene (180 mg/day for 1...
Article
A summary is given of the biology of human melanin pigmentation. The authors discuss the pathophysiology of vitiligo. Trioxsalen is considered to be the most effective treatment. The failures in the past are considered to be due primarily to two factors: the dosage being too low, and the treatment being too short in duration. The treatment regimen...
Article
Recent observations and theories implicating long-wave ultraviolet radiation (320-400 nm) as the stimulus for various phenomena in human skin have prompted us to investigate the erythemogenic properties of middle (UV-B) and long (UV-A) wave ultraviolet light combinations. The backs of fair-skinned human volunteers were irradiated with varying doses...
Article
Histochemical (dopa reaction) and electron microscopic studies were carried out to elucidate the nature of the chemical depigmentation produced by hydroquinone (HQ). Depigmentation was induced by topical application or subcutaneous injection of HQ in black guinea pigs. The present study showed that HQ preferentially affected the nonfollicular and f...
Article
Full-text available
Ultrastructural changes in melanocytes and keratinocytes during immediate tanning were studied on 6 volunteers, among whom were 4 caucasoids, 1 mongoloid, and 1 negroid. The site of biopsy specimens before and after irradiation involved unexposed skin of buttock, and habitually exposed (tanned) skin of forearm (lateral as well as medial aspects). I...
Article
Exposure of caucasoid skin to longwave ultraviolet light (uv) after the application of psoralens resulted in an increase in the average size of the melanosomes and changes in the distribution pattern of melanosomes within the keratinocytes. The photobiologic mechanism responsible for the changes in the size of melanosomes is still not clear. Howeve...
Article
A patient suffering from polymorphous light eruption did not respond to conventional modes of therapy. Phototesting demonstrated that he was sensitive to light from 290 to 500 nm. The patient was treated with a combination of sulisobenzone and β-carotene, with amelioration of the disease.
Article
The application of trimethylpsoralen and ultraviolet light exposure to the epidermis influences directly or indirectly keratinization in the epidermis. The ultraviolet light irradiation accelerated by the photosensitizer, trimethylpsoralen affects the distribution pattern of the melanosomes in the keratinocytes of the epidermis. The distribution pa...
Article
Beta-carotene (180 mg/day, p. o. ) or a placebo was administered to 30 normal male volunteers for 10 weeks, after which the volunteers were exposed to sunlight in the Arizona desert for up to 2 hours. Beta-carotene had a small but statistically significant effect in increasing the minimal erythema dose of sunburn radiation. The observed effects wer...