New Data on Cylindrospermopsin Toxicity

Cylindrospermopsin (CYN) is a widely spread cyanotoxin that can occur in fresh water and food. This research aims to investigate CYN toxicity by studying the effects of drinking 0.25 nM of CYN-contaminated water from a natural source, and of the direct application of moderate concentrations of CYN on different animal targets. The chosen structures and activities are rat mitochondria inner membrane permeability, mitochondrial ATP synthase (ATPase) and rat liver diamine oxidase (DAO) activities (EC 1.4.3.22.), the force of the contraction of an excised frog heart preparation with functional innervation, and the viability of a human intestinal epithelial cell line (HIEC-6). The oral exposure to CYN decreased the reverse (hydrolase) activity of rat liver ATPase whereas its short-term, in vitro application was without significant effect on this organelle, DAO activity, heart contractions, and their neuronal regulation. The application of CYN reduced HIEC-6 cells’ viability dose dependently. It was concluded that CYN is moderately toxic for the human intestinal epithelial cells, where the regeneration of the epithelial layer can be suppressed by CYN. This result suggests that CYN may provoke pathological changes in the human gastrointestinal tract.

PENGARUH ZAT KIMIA PADA BERBAGAI SUHU TERHADAP DENYUT JANTUNG KATAK (Rana sp.) DALAM UPAYA PENGEMBANGAN BUKU PETUNJUK PRAKTIKUM FISIOLOGI HEWAN

The purpose of this study is to determine the effect of chemicals on various temperatures in the heart of frogs (Rana sp.) And to compile valid animal physiology practical instructions. This research is a type of experimental research (true experimental) and this research approach is a qualitative approach. Samples were given 3 different treatments, namely controls with room temperature of 250C-300C, temperature of 00C-100C, and 300C-400C. The results of the study using ANOVA (Analysis of Variance) showed the effect of NaCl solution on the frog heart rate (Rana sp.) Namely Fcount of 5.18 while Ftable of 3.59 so that the results of this study were declared significant. While the effect of saline solution on the frog heart rate (Rana sp.) Is Fcount of 1.78 while Ftable is 3.59 so the results of this study are declared non-significant. So it can be concluded that, NaCl solution at various temperatures significantly influences the frog heart rate (Rana sp.), While saline solution at various temperatures does not significantly influence the frog heart rate (Rana sp.). The process of developing this animal physiology practical guide uses a 3-D development model, which consists of the define, design, and develope stages. The results of the study showed that the practicum instructions for animal physiology were valid, said to be valid because the practicum instructions prepared and developed had met the "valid" criteria.

A questionnaire-based comparison of conventional teaching methods to computer assisted learning in experimental pharmacology for undergraduate medical students

Background: Computer Assisted Learning (CAL) for teaching experimental pharmacology is now widely accepted as alternative to animal experiments. The objective of this study was to compare the performance of undergraduate medical students by conventional teaching methods (lecture and discussion) and CAL.Methods: This was a questionnaire based observational study involving 109 MBBS students of fifth semester. The students were taught experimental pharmacology practical by both conventional methods (lecture with discussion) and computer assisted learning (CAL). Questionnaire and their filled responses by these students were taken at the end of lecture-discussion (pre-CAL) and after the CAL experiments (post-CAL), covering the same topics of experimental pharmacology. Pre-CAL and post-CAL data were assessed statistically.Results: In the pre-CAL session, only 53.39%, 47.56%, 53.39% and 49.5% of the students were having the scores above 40% in the rabbit eye, DRC and potentiation, frog heart and dog BP experiment respectively, which was increased to 77.44%, 75.48%, 75.47% and 75.48% of the students respectively in the post-CAL assessment. A statistically significant difference (p <0.05) in the performance was observed among the students in the pre-CAL and post-CAL assessment.Conclusions: CAL is a good alternative to animal experimentation. Lecture with discussion, followed by CAL experiments on the same topics, enhanced the performance of students as shown by improvement in post-CAL scores.

Effect of Coscinium Fenestratum stem extracts on hypertension in animal model

This study was done to evaluate the anti-hypertensive effects of stem extract of Coscinium fenestratum (CF). The stems were air dried for 2 days, grounded and then soaked in organic solvent for 2 days. Thereafter the filtered extract was concentrated using rotary evaporator at 450C to obtain the crude extract. Partial purification was done using silica gel column chromatography to separate the crude extract into five fractions A-E. The effect on hypertension was tested by intravenous injection of each extractinto a normotensive anaesthetized rat andperfused frog heart. The effect Mean Arterial Blood Pressure (MABP), Heart rate (beats per minute) (HR) and force of contraction (FOC) was recorded via the BIOPAC LAB PRO SOFTWARE. The phytochemical compound present in the extract was identified using a simple colorimetric biochemical method. The extract showed a reduction of theMABP, HR and FOC in the presence of norepinephrine and without norepinephrine. The effect of the extract was more than that of commercial drug atenolol. Colorimetric phytochemistry testing revealed the presence of flavonoids, terpenoids, saponins, tanins, cardiac glycoside and alkaloids. The effect maybe because of the type of bioactive compounds present in the extract which has previously shown antioxidant property.

Ganglionic and non-ganglionic neurons in frog heart: do they differ?

This study was designed to compare the morphology of neurons in relation to their distance from the major nerve trunks in the heart of the frog Rana temporaria. Seventy-nine intracardiac neurons were labelled intracellularly with fluorescent markers Lucifer Yellow CH and Alexa Fluor 568. The neurons located on the extensions of the vagus nerve were considered as ganglionic, while neurons spread loosely at further distance from these extensions were considered as non-ganglionic. The mean area of the soma in ganglionic neurons was about 25% larger than in non-ganglionic neurons. Ganglionic neurons had a higher soma area/nucleus area ratio than non-ganglionic neurons. Although both the total number and the total length of dendrite-like processes was similar between the two groups, ganglionic neurons had significantly fewer dendrite-like processes from the soma (1.5±0.3 vs. 3.9±1.0; P<0.05) and shorter total length of these processes from the soma (63±18 μm vs. 178±51 μm; P<0.05). In conclusion, ganglionic and non-ganglionic frog intracardiac neurons exhibit substantial morphological differences. We hypothesize that these differences may indicate different projections or variations in the number of their preganglionic inputs.