Comparison of vertebrate skin structure at class level: A review.

The skin is a barrier between the internal and external environment of an organism. Depending on the species, it participates in multiple functions. The skin is the organ that holds the body together, covers and protects it, and provides communication with its environment. It is also the body's primary line of defense, especially for anamniotes. All vertebrates have multilayered skin composed of three main layers: the epidermis, the dermis, and the hypodermis. The vital mission of the integument in aquatic vertebrates is mucus secretion. Cornification began in apmhibians, improved in reptilians, and endured in avian and mammalian epidermis. The feather, the most ostentatious and functional structure of avian skin, evolved in the Mesozoic period. After the extinction of the dinosaurs, birds continued to diversify, followed by the enlargement, expansion, and diversification of mammals, which brings us to the most complicated skin organization of mammals with differing glands, cells, physiological pathways, and the evolution of hair. Throughout these radical changes, some features were preserved among classes such as basic dermal structure, pigment cell types, basic coloration genetics, and similar sensory features, which enable us to track the evolutionary path. The structural and physiological properties of the skin in all classes of vertebrates are presented. The purpose of this review is to go all the way back to the agnathans and follow the path step by step up to mammals to provide a comparative large and updated survey about vertebrate skin in terms of morphology, physiology, genetics, ecology, and immunology.

A Histological Study on Venom Apparatus of Montivipera xanthina (Gray, 1849) (Serpentes, Viperidae)

ABSTRACT This is the first report describing morphological and histological structure of venom apparatus in Montivipera xanthina. The venom gland apparatus of M. xanthina was composed of four distinct parts, main venom gland, primary duct, accessory gland and secondary duct. The main venom gland was composed of acini. The accessory gland was formed by long and ramified tubules. Nine fangs were detected in one half of the upper jaw each at different stage of development. Only one tooth was functional and the eight remaining fangs form a replacement series. The venom apparatus of viperid snakes are the most effective venom-delivery system among vertebrates and have been the focus of scientific interests for many years. Despite this interest, there are few studies including venom-delivery system of venomous snakes. The results presented here may be common among venomous snakes and model of the viperid design of the venom apparatus.

Propanil-induced histopathological changes in the liver and kidney of mice.

OBJECTIVE: To examine sublethal toxic effects of propanil on liver and kidney of albino Swiss mice, Mus musculus. STUDY DESIGN: Different doses of propanil (75, 150, and 300 mg/kg) were administered to determine histologic defects on liver and kidney tissues of mice for 30 consecutive days. Biometric analyses (area measurements of hepatocyte/nucleus and glomerulus/renal corpuscle) were also conducted to determine whether there were statistical differences in these end points. RESULTS: Cloudy swelling, cytoplasmic vacuolization, nuclear degeneration, nucleus loss, mononuclear cell infiltration, congestion, enlargement of the sinusoids, and increases in the number of Kupffer cells were prominent in the liver of exposed mice. In kidney tissue mononuclear cell infiltration, glomerular degeneration, glomerular loss, and congestion were determined in propanil-treated groups. CONCLUSION: Propanil induced dose-dependent histopathological changes in the liver and kidney tissues of exposed mice. This study showed that propanil exposure might cause harmful effects to nontarget organisms, including humans.

Effects of oral exposure to diazinon on mice liver and kidney tissues: biometric analyses of histopathologic changes.

OBJECTIVE: To determine the sublethal toxic effects of diazinon on liver and kidney tissues of Swiss albino mice. STUDY DESIGN: Mice were exposed to different concentrations (30, 60, and 120 mg/kg) of diazinon through oral administration for 30 consecutive days. Biometric analyses (area measurements of histologic structures) of some histopathological changes were evaluated by measuring the areas of hepatocyte/nucleus in the liver and the areas of glomerulus and renal corpuscle in the kidney. Both glomerular area and renal corpuscle area statistically decreased from the low-dose group to high-dose group as compared to controls. RESULTS: In liver tissue vacuolization in hepatocytes, mononuclear cell infiltration, congestion, enlargement of the veins, and an increase in the number of Kupffer cells were found in the liver of exposed mice. In kidney tissue, mononuclear cell infiltration, glomerular degeneration, glomerular loss, and congestion were observed in diazinon-treated groups. CONCLUSION: Diazinon caused dose-related histopathological damage in liver and especially in kidney tissues of mice. This work indicates that it might cause adverse effects to nontarget organisms, including humans.

Histopathological effects of carbaryl on digestive system of snake-eyed lizard, Ophisops elegans.

We examined the effects of carbaryl in the digestive system of Ophisops elegans. Lizards were exposed once to different concentrations of carbaryl (2.5, 25 and 250 µg/g). After 96 h, findings related to the esophagus in all treatment groups were not conspicuous. The most important histological defects were observed in the stomach. In the small intestine, collapse of villi was prominent at high-dose. In the large intestine, disintegration in epithelial cells and scattered secretory granules of goblet cells were observed at high dose.

Histopathological effects of carbaryl on testes of snake-eyed lizard, Ophisops elegans.

BACKGROUND, AIM AND SCOPE: Due to their ecological niche and insectivore nature, lizards are of increased risk of exposure to pesticides in agricultural areas. In addition to their potential direct effects on non-target species, insecticides can also result in indirect impacts on lizard population by reducing their food source. Carbaryl is a common insecticide that is widely used in areas of Turkey that are home to a variety of reptiles. However, to date, little is known about the potential effects of the exposure of reptiles such as lizards or snakes to this pesticide. The aim of the study was to investigate toxic effects of carbaryl on the testes of snake-eyed lizard, Ophisops elegans that is common to regions in Turkey where Carbaryl is applied and that it can be easily cultured in the laboratory. MATERIAL AND METHODS: Adult male lizards were exposed to carbaryl once by oral gavage in concentrations of 2.5, 25 and 250 µg/g. After 96 h, lizards were euthanized and dissected. Histopathological changes were detected by randomly counting 100 tubules in each lizard. Seminiferous tubules were categorized as normal, sloughing and disorganized tubules. Diameters of tubules were also measured. The differences in histopathological changes and tubule diameters were compared for statistical significance by one-way ANOVA, using SPSS 16.0. RESULTS AND DISCUSSION: Histopathological changes were more prominent in medium- (25 µg/g) and high-dose (250 µg/g) groups than in the low-dose (2.5 µg/g) group. In the medium-dose group, the hexagonal appearance of most tubules disappeared, and they took on an oval shape. Sloughing was the characteristic tubule appearance of the medium group. In the high-dose group, significant increases in the number of disorganized tubules and prominence of haemorrhages was observed. CONCLUSION: Carbaryl caused histopathological defects on the testes of O. elegans, so it is clear that carbaryl affects male fertility in O. elegans.