Publications by authors named "K Karthikeyan"

245 Publications

Lupus Vulgaris.

Am J Trop Med Hyg 2021 Sep 13. Epub 2021 Sep 13.

Department of Dermatology, Venereology and Leprosy, Sri Manakula Vinayagar Medical College and Hospital, Pondicherry, India.

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http://dx.doi.org/10.4269/ajtmh.21-0736DOI Listing
September 2021

Pineal Anaplastic Ependymoma - A Rare Entity.

Neurol India 2021 Jul-Aug;69(4):1045-1047

Department of Neurosurgery, Chettinad Hospital and Research Institute, Kelambakkam, Chennai, Tamil Nadu, India.

Anaplastic ependymoma in the pineal region is rare. Here, we present a rare case of anaplastic ependymoma of the pineal region on a 42-year-old woman who came to our hospital with headache associated with blurring of vision since one month. MRI brain showed a contrast enhancing mass lesion measuring 30 × 30 × 35 mm in the pineal region with obstructive hydrocephalus. Initially, the ventriculoperitoneal (VP) shunt was done, followed by total tumor excision by the infratentorial supracerebellar approach. Histopathological and immunohistochemistry examinations of the tumor showed the features of anaplastic ependymoma (WHO Grade III). Patient made uneventful recovery and underwent radiotherapy. Only 12 cases of pineal ependymoma have been reported so far, of which only three have been anaplastic ependymoma.
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http://dx.doi.org/10.4103/0028-3886.325365DOI Listing
September 2021

Serine Mutations in Hsp27 abrogate its ability to inhibit p53 dependent apoptosis and Doxorubicin-induced Heart Failure in mice.

Am J Physiol Heart Circ Physiol 2021 09 3. Epub 2021 Sep 3.

Division of Cardiovascular Medicine, Davis Heart & Lung Research Institute, Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States.

Small heat shock proteins (sHsps) protect the heart from chemotherapeutics-induced heart failure, by inhibiting p53-dependant apoptosis. However, mechanism of such protection has not been elucidated yet. Here we test a hypothesis that serine phosphorylation of sHsps is essential to inhibit the Doxorubicin-induced p53-dependent apoptotic pathway. Three transgenic mice (TG) lines with cardiomyocyte specific overexpression of human heat shock protein 27 (hHsp27), namely, wild type (MHC-hHsp27), S82A single mutant (MHC-mut-hHsp27(S82A) and tri-mutant (MHC-mut-hHsp27(S15A/S78A/S82A)) were generated. TG mice were treated with Dox (6mg/kg body weight; once in a week; 4 weeks) along with age-matched non-transgenic (Non-TG) controls. The Dox-treated MHC-hHsp27 mice showed improved survival and cardiac function (both MRI and echocardiography), in terms of contractility (%EF) and left ventricular inner diameter (LVID), compared to the Dox-treated Non-TG mice. However, both MHC-mut-hHsp27(S82A) and MHC-mut-hHsp27(S82A/S15A/S76A) mutants overexpressing TG mice did not show such a cardioprotection. Furthermore, transactivation of p53 was found to be attenuated only in Dox-treated MHC-hHsp27 mice-derived cardiomyocytes in vitro, as low p53 was detected in the nuclei, not in mutant hHsp27 overexpressing cardiomyocytes. Similarly, only in MHC-hHsp27 overexpressing cardiomyocytes, low Bax, higher mTOR phosphorylation and low apoptotic PARP-1 cleavage (89kDa fragment) were detected. Pharmacological inhibition of p53 was more effective in mutant-TG mice, compared to MHC-hHsp27 mice. We conclude that phosphorylation of overexpressed Hsp27 at S82 and its association with p53 is essential for the overall cardioprotective effect of Hsp27 against Dox-induced dilated cardiomyopathy. Only phosphorylated Hsp27 protect the heart by inhibiting p53 transactivation.
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http://dx.doi.org/10.1152/ajpheart.00027.2020DOI Listing
September 2021

Fragrance, Sunscreens, Botanicals, and Potential Allergens in Bestseller 'Fairness' Creams in the Indian Market: A Consumer Exposure Study.

Indian J Dermatol 2021 May-Jun;66(3):279-283

Department of Dermatology, All India Institute of Medical Sciences, Mangalagiri, Guntur District, Andhra Pradesh, India.

Background: The skin lightening industry has seen exponential growth in India. Consumers often present to the dermatologist with adverse cutaneous reactions to these 'fairness' (skin lightening) creams. The composition of these creams has not received sufficient attention.

Objective: To identify fragrance, sunscreens, botanicals and potential allergens in the bestseller 'fairness' creams available in the Indian market.

Methods: Twenty fairness (or whitening or lightening) creams were selected based on the 'bestseller' creams of one of the largest electronic commerce websites in India, and availability in local stores and unlabelled brands were excluded. Fragrance, sunscreens, botanicals and potential allergens were identified from the ingredient labels.

Results: Twenty bestseller fairness creams were included. The number of the listed ingredients in the fairness creams ranged from 6 to 49 (mean = 32.2). The most frequently listed ingredients included water, fragrance or parfum, glycerin, tocopherol/tocopherylacetate and titanium dioxide. Hydroquinone, monobenzyl hydroquinone, corticosteroids, tretinoin and mercury were not listed in any of the creams. Unspecified fragrance was listed in 19 (95%) creams and linalool (8,40%) was the most frequent specified fragrance. Titanium dioxide (14, 70 %) was the most common inorganic sunscreen and ethylhexyl methoxycinnamate (12 creams or 60% of creams) was the most common organic sunscreen. Twenty-seven botanicals were identified. Eight ingredients were potential allergens according to the Indian Cosmetic and Fragrance Series. The cost of the creams ranged from 95 to 1,095 in Indian rupees (mean 300.5).

Conclusions: Consumers are exposed to a vast range of compounds in the quest for a lighter skin tone. Several potential allergens, particularly fragrance allergens, are present in addition to the eight allergens that were identified with the Indian Cosmetic and Fragrance Series. Increased awareness of the composition of skin lightening creams available in the market and strict regulation of these creams is needed.
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http://dx.doi.org/10.4103/ijd.IJD_500_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8375543PMC
August 2021

Effects of severe pretreatment conditions and lignocellulose-derived furan byproducts on anaerobic digestion of dairy manure.

Bioresour Technol 2021 Nov 22;340:125632. Epub 2021 Jul 22.

Department of Biological Systems Engineering, University of Wisconsin-Madison, 460 Henry Mall, Madison, WI 53706, United States. Electronic address:

Dairy manure subjected to four pretreatments (acid, alkaline, sulfite (SPORL), alkaline hydrogen peroxide (AHP)) at high chemical dosages (termed severe conditions) were evaluated for enhancements in biogas production and inhibitory effects due to concomitant generation of furan byproducts. All four pretreatments enhanced solubilization of carbohydrates, but only alkaline and AHP resulted in higher methane yield (356 and 333 mL/g-VS, respectively) relative to moderate pretreatment conditions (311 and 261 mL/g-VS, respectively). Methane yield of severe-SPORL pretreatment (233 mL/g-VS) was greater than that of untreated manure (116 mL/g-VS), but lower than that of moderate-SPORL (353 mL/g-VS). Severe-acid pretreatment showed early termination in biogas production likely due to inhibitory effects of furfural and 5-hydroxymethyl furfural. Both experimental data and kinetic modeling indicated that severe-acid pretreatment led to degradation of carbohydrates to furfural, which reduced biogas production due to direct toxicity rather than competitive inhibitory effects. Pretreatment conditions (severity and byproduct levels) for dairy manure biomass may be optimized based on the current findings.
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http://dx.doi.org/10.1016/j.biortech.2021.125632DOI Listing
November 2021
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