Combinatorial effect of nicotine and black tea on heart rate variability: Useful or harmful?

The effect of nicotine on heart rate variability (HRV) is controversial. Autonomic nervous system is the main regulator of heart rhythm, and heart rate variability is an appropriate index to assessment of the effects of the autonomic system on heart. In this study, the combination effect of nicotine and black tea consumption on sympatho-vagal balance and heart rate variability was investigated in rats. Male Wistar rats were randomized into four groups as control, tea (2.5 g/100 cc, daily), nicotine (2 mg/kg/d) and tea plus nicotine groups which treated for 28 days, and in the 29th day, their electrocardiograms (lead II) were recorded. The mean of high-frequency power (HF) in tea, nicotine and tea plus nicotine groups was significantly more than control group (P < .05), and low-frequency power/high-frequency power (LF/HF) ratio in the nicotine and tea + nicotine groups was significantly less than control group (P < .05). LF values did not differ significantly among groups. Mean of standard deviation of normal RR intervals (SDNN) and square root of the mean squared differences of successive RR intervals (RMSSD) increased significantly in tea, nicotine and tea + nicotine groups in comparison with control group (P < .05) Overall, 4-week administration of black tea, nicotine or their combination with dosages used in this study can increase the heart rate variability and improve the sympatho-vagal balance in rat.

Morphological Study of the Persian Leopard (Panthera pardus saxicolor) Tongue.

This study described the morphological features of the Persian leopard (Panthera pardus saxicolor) tongue using light and scanning electron microscopy techniques. The keratinized filiform papillae were distributed all over the entire dorsal surface of the tongue and contained small processes. They were changed into a cylindrical shape in the body and conical shape in the root. The fungiform papillae were found on the apex and margin of the tongue. Few taste pores were observed on the dorsal surface of each papilla. The foliate papillae on the margins of the tongue were composed of several laminae and epithelial fissures. Taste buds were not seen within the non-keratinized epithelium. The vallate papillae were six in total and arranged in a "V" shape just rostral to the root. Each papilla was surrounded by a groove and pad. Taste buds were seen within their lateral walls. Lyssa was visible on the ventral surface of the tongue tip and was found as cartilaginous tissue surrounded by thin connective tissue fibres. The core of the tongue was composed of lingual glands, skeletal muscle and connective tissue. These glands were confined to the posterior portion of the tongue and were composed of many serous cells and a few mucous cells. The results of this study contributed to the knowledge of the morphological characteristics of the tongue of wild mammals and provided data for the comparison with other mammals.

Induction of somatic embryogenesis in saffron using thidiazuron (TDZ).

In vitro propagation of saffron either through somatic embryogenesis or cormogenesis is considered to be an efficient alternative method for large-scale propagation of pathogen-free corms. In order to develop an efficient protocol for in vitro propagation of saffron, a factorial experiment was carried out based on completely randomized design to investigate the effects of various concentrations of TDZ (0, 0.1, 0.25 and 0.5 mg L(-1)) on somatic embryogenesis induction from 5 different types of corm explants (terminal or axillary buds, upper or lower parts of the corm tissue and terminal buds from pre-treated corms at 4 degrees C for 2 weeks). The results revealed that TDZ concentrations affected the induction of somatic embryogenesis significantly while different types of corm explants showed no significant effect on this process. Among TDZ concentrations used, 0.5 mg L(-1) was the most effective treatment for embryogenesis induction. Embryogenic calli (globular stage) proliferated well when subcultured into MS medium supplemented with 0.25 mg L(-1) TDZ before transferring to hormone-free MS medium containing 6% sucrose for maturation (scutellar or horn-shape stage). Matured embryos were transferred to half strength MS medium without growth regulators for further development, from which microcorms were produced at the basal part after 3 months.