Phenylthiourea Specifically Reduces Zebrafish Eye Size

Phenylthiourea (PTU) is commonly used for inhibiting melanization of zebrafish embryos. In this study, the standard treatment with 0.2 mM PTU was demonstrated to specifically reduce eye size in larval fish starting at three days post-fertilization. This effect is likely the result of a reduction in retinal and lens size of PTU-treated eyes and is not related to melanization inhibition. This is because the eye size of tyr, a genetic mutant of tyrosinase whose activity is inhibited in PTU treatment, was not reduced. As PTU contains a thiocarbamide group which is presented in many goitrogens, suppressing thyroid hormone production is a possible mechanism by which PTU treatment may reduce eye size. Despite the fact that thyroxine level was found to be reduced in PTU-treated larvae, thyroid hormone supplements did not rescue the eye size reduction. Instead, treating embryos with six goitrogens, including inhibitors of thyroid peroxidase (TPO) and sodium-iodide symporter (NIS), suggested an alternative possibility. Specifically, three TPO inhibitors, including those that do not possess thiocarbamide, specifically reduced eye size; whereas none of the NIS inhibitors could elicit this effect. These observations indicate that TPO inhibition rather than a general suppression of thyroid hormone synthesis is likely the underlying cause of PTU-induced eye size reduction. Furthermore, the tissue-specific effect of PTU treatment might be mediated by an eye-specific TPO expression. Compared with treatment with other tyrosinase inhibitors or bleaching to remove melanization, PTU treatment remains the most effective approach. Thus, one should use caution when interpreting results that are obtained from PTU-treated embryos

Wegener′s Granulomatosis An unusual Presentation

Wegenâ€s granulomatosis is characterized by necortising granulomatous inflammation and vasculitis affecting predominantly small arteries and veins. In its generalized from there is involvement of upper and lower respiratory tract, kidney and often other organs including skin. It may also present as limited organ involvement. A case of Wegenerâ€s granuolmatosis limited to skin is reporte

Profile Of Leishmaniasis In Central Kerala

Leishmaniasis is a group of diseases caused by several species of the genus leishmania. It is not prevalent in Kerala even though there are a few case reports. Recently, a focus of indigenous leishmaniasis is located in the north- east part of Kerala. We are also reporting probably indigenous cases along with those contracted from Middle- east countries

Periorbital mass with cellulitis caused by dirofilaria

Dirofilariasis is a zoonotic disease caused by Dirofilaria , a parasite of domestic and wild animals. The disease is transmitted by inoculation of mosquitoes infected with the microfilariae during their blood meal. Accidental infection of man results in lung nodule, subcutaneous mass anywhere in the body or ocular lesion that may be subconjunctival or periorbital. The incidence of ocular dirofilariasis is on the rise in several parts of India particularly in Kerala. Here we report a case of ocular dirofilariasis with cellulitis presenting as a periorbital mass