Misconceptions about the menstrual cycle among students of the teaching major of the integrated study of biology and chemistry

Dosad provedena istraživanja o miskoncepcijama o menstruacijskom ciklusu pokazala su da su miskoncepcije široko rasprostranjene u različitim populacijama i da razina obrazovanja nema bitan učinak na tu pojavu. Najčešće miskoncepcije su da se ovulacija odvija u sredini ciklusa ili da se odvija četrnaestog dana ciklusa. Utvrđeno je da zabilježene miskoncepcije proizlaze iz prikaza menstruacijskog ciklusa od 28 dana koji je prisutan posvuda, bez iznimki. Unatoč pronađenom rješenju, materijal za poučavanje se nije mijenjao. Cilj ovog istraživanja bio je utvrditi prisutnost miskoncepcija o menstruacijskom ciklusu kod studenata nastavničkog smjera integriranog studija biologije i kemije i njihovu sposobnost određivanja dana ovulacije u ciklusu koji ne traje 28 dana te usporediti rezultate s rezultatima istraživanja koje je ranije provedeno na uzorku učenika gimnazija u Zagrebu, a čiji su rezultati objavljeni 2018. godine. Istraživanje je provedeno na uzorku od ukupno 98 studenata tijekom šest godina, od 2012. do 2017. godine. Rezultati pokazuju da je udio studenata koji su točno odredili dan ovulacije mali i ne značajno bolji od rezultata koje su postigli gimnazijalci i da je udio miskoncepcija u njihovim obrazloženjima vrlo velik te da je, unatoč višekratnom poučavanju o menstruacijskom ciklusu ili možda upravo zbog poučavanja uz pomoć neprimjerenog vizualnog materijala, pojava miskoncepcija jače izražena nego kod gimnazijalaca.A large number of scientific articles shown that misconceptions about the menstrual cycle are widespread in different populations and that the level of education has no significant effect on this phenomenon. The most common misconceptions are that that ovulation occurs in the middle of the cycle or that ovulation occurs on the fourteenth day of the cycle. It was found that the recorded misconceptions origin from the representation of the 28-day menstrual cycle that is present in all educational materials, without exception. Despite the solution found, the teaching material did not change. The aim of this research was to determine the presence of misconceptions about the menstrual cycle among students of the Integrated undergraduate and graduate programme Biology and Chemistry Education and their ability to determine the day of ovulation in a cycle that does not last 28 days. Furthermore, another aim was to compare the results of the university students with the results of a previously conducted research on a sample of high school students in Zagreb, published in 2018. The research was conducted on a sample of a total of 98 students in a period of six years, from 2012 to 2017. The results show that the proportion of students who accurately determined the day of ovulation is small and not significantly higher than the results achieved by high school students, and that the proportion of misconceptions in their explanations is very high. Furthermore, results show that, despite repeated teaching about the menstrual cycle or perhaps because of teaching with the help of inappropriate visual material, the occurrence of misconceptions is more pronounced among university students than among high school students

Učinak flavonoida na simbiozu hidre i alge i primjena navedenog eksperimenta u školama

Hydra (Cnidaria) is a cosmopolite freshwater invertebrate that establishes symbiosis with unicellular algae. Its simple body is comprised of three layers: epidermis, mesoglea and gastrodermis. The goal of this research was to determine the effect of flavonoids quercetin and naringenin upon hydra – alga symbiosis, to determine how motivated teachers are to perform such a mode of teaching and whether this motivation depends on their age, years of working experience, the school they work in, available time, space and material. An anonymous survey on a sample of 100 biology teachers was used in the research. Hydras and algae were treated with quercetin and naringenin in concentrations of 0.2, 0.25 and 0.3 gL−1 and compared to the control, and Chlorella bioassay was used. Morphological changes included migration, reaction to mechanical stimuli, asexual reproduction, secretion of mucus and mortality. Cyto-histological analysis revealed changes of all three layers and growth inhibition. Naringenin exerted altogether higher impact than quercetin. Survey results indicated that teachers are willing to use this experiment in school, and that most schools have the minimum required equipment. Because of the possibility of adapting this experiment in different temporal and spatial conditions, its performance in school is suggested.Hydra (Cnidaria) je kozmopolitski slatkovodni beskralježnjak koji uspostavlja simbiozu s jednostaničnim algama. Njezino jednostavno tijelo sastoji se od tri sloja: epiderma, mezogleje i gastroderma. Cilj ovoga istraživanja bio je utvrditi utjecaj flavonoida kvercetina i naringenina na simbiozu hidre i alge, odrediti koliko su nastavnici motivirani za primjenu takvog načina poučavanja te ovisi li navedena motivacija o njihovoj dobi, godinama radnog iskustva, školi u kojoj rade, raspoloživom vremenu, prostoru i materijalima. U istraživanju je upotrijebljena anonimna anketa na uzorku od 100 nastavnika biologije. Hidre i alge tretirane su kvercetinom i naringeninom pri koncentracijama od 0,2, 0,25 i 0,3 gL-1 i uspoređene su s kontrolnim uzorkom, a koristio se biološki test Chlorella test. Morfološke promjene uključivale su migraciju, reakciju na mehaničke podražaje, nespolno razmnožavanje, izlučivanje sluzi i smrtnost. Citološko-histološkom analizom utvrđene su promjene svih triju slojeva, kao i inhibicije rasta. Naringenin je imao ukupno veći učinak od kvercetina. Rezultati dobiveni anketom pokazali su da su nastavnici spremni izvoditi navedeni eksperiment u školi te da većina škola ima minimalnu potrebnu opremu. Zbog mogućnosti prilagodbe opisanog eksperimenta različitim vremenskim i prostornim uvjetima, predlaže se njegova primjena u školi

Efficacy of Caffeic Acid on Diabetes and Its Complications in the Mouse

Diabetic dyslipidemia and hyperglycemia contribute to excessive reactive oxygen species (ROS) production, leading to deleterious complications, such as nephropathy, atherosclerosis and cardiac dysfunction, and target major organs in the body. The aim of this study was to investigate the effect of caffeic acid (CA) on mouse weight and survival, serum level of fasting blood glucose (FBG), serum lipid parameters and atherogenic indices, oxidative damage in blood, liver and kidney tissue, pathophysiological changes and their function markers in healthy and alloxan-induced type 1 diabetic mice. Diabetes was induced in mice with a single intravenous injection of alloxan (75 mg/kg). Two days later, CA (50 mg/kg) was given intraperitoneally for seven days in diabetic mice. Diabetes affected glucose level, lipid profile, hematological and biochemical parameters, induced DNA damage and apoptotic/necrotic death in whole blood cells, liver and kidney, leading to weight loss and a decreased lifespan. CA treatment of diabetic mice revealed a protective effect on the liver and kidney, hypoglycemic and hypolipidemic properties and high protection against atherogenic outcomes. The obtained results suggest that CA is a safe and potent agent against diabetes that acts as an effective antioxidant in reducing serum glucose, lipid profile and atherogenic indices, leading to increased lifespan in mice

Naringenin ameliorates pathological changes in liver and kidney of diabetic mice: a preliminary study

Istražen je učinak naringenina, flavonoida dostupnoga iz grejpa, naranče i rajčice, na razinu lipidne peroksidacije te patohistološke promjene u jetri i bubregu miševa s dijabetesom prouzročenim aloksanom. Dva dana nakon injekcije aloksana (75 mg kg-1, iv) započeta je terapija etanolnom otopinom naringenina (0.5% v / v). Naringenin je injiciran miševima intraperitonealno u dozi od 50 mg kg-1 tijekom sedam dana. Učinak naringenina na razinu lipidne peroksidacije određen je metodom s tiobarbiturnom kiselinom, a histopatološke promjene jetre i bubrega utvrđene su svjetlosnim mikroskopom. Terapija naringeninom prouzročila je značajno smanjenje ne samo razine lipidne peroksidacije u tkivu jetre i bubrega nego i broja vakuoliziranih stanica jetre te stupnja njihove vakuolizacije. Naznake oporavka tkiva u bubregu navode na zaključak da bi dugotrajna terapija mogla smanjiti oštećenja bubrega prouzročena dijabetesom. Zaštitni učinak naringenina u razvoju dijabetičkih komplikacija u miševa daje nadu da je sličan, pozitivan učinak moguć i u ljudi.The effect of naringenin, a flavonoid found in grapefruit, orange, and tomato, on lipid peroxidation and histopathological changes in the liver and kidneys of alloxan-induced diabetic mice were investigated. Two days after alloxan injection (75 mg kg-1, i.v.), naringenin ethanolic solution (0.5 % v/v) was given to mice intraperitoneally (50 mg kg-1 per day) for seven days. Naringenin’s impact on lipid peroxidation was measured by the 2-thiobarbituric acid test and histopathological changes were examined under a light microscope. Naringenin administration resulted in a significant decrease of lipid peroxidation level in liver and kidney tissue, as well as in a decreased number of vacuolated liver cells and degree of vacuolisation. Indications of tissue repair in kidney suggested that amelioration of diabetes-induced renal damage could be achieved over a longer period of time. Findings suggest that naringenin could be considered a dietary supplement in the prevention or treatment of diabetic complications and other diseases connected wih oxidative stress, and gives a hope that it could show similar effects in the treatment of diabetes in humans

Effect of Croatian propolis on diabetic nephropathy and liver toxicity in mice

Abstract Background In the present study, we examined the antioxidant effect of water soluble derivative of propolis (WSDP) and ethanolic (EEP) extract of propolis on renal and liver function in alloxan-induced diabetic mice. In addition, we examined whether different extract of propolis could prevent diabetic nephropathy and liver toxicity by inhibiting lipid peroxidation in vivo. Methods Diabetes was induced in Swiss albino mice with a single intravenous injection of alloxan (75 mg kg-1). Two days after alloxan injection, propolis preparations (50 mg kg-1 per day) were given intraperitoneally for 7 days in diabetic mice. Survival analysis and body weights as well as hematological and biochemical parameters were measured. The renal and liver oxidative stress marker malonaldehyde levels and histopathological changes were monitored in the liver and kidney of treated and control mice. Results Administration of propolis to diabetic mice resulted in a significant increase of body weight, haematological and immunological parameters of blood as well as 100% survival of diabetic mice. Alloxan-injected mice showed a marked increase in oxidative stress in liver and kidney homogenate, as determined by lipid peroxidation. Histopathological observation of the liver sections of alloxan-induced diabetic mice showed several lesions including cellular vacuolization, cytoplasmic eosinophilia and lymphocyte infiltrations, but with individual variability.Treatment of diabetic mice with propolis extracts results in decreased number of vacuolized cells and degree of vacuolization; propolis treatment improve the impairment of fatty acid metabolism in diabetes. Renal histology showed corpuscular, tubular and interstitial changes in alloxan-induced diabetic mice. Test components did not improve renal histopathology in diabetic mice. Conclusions Propolis preparations are able to attenuate diabetic hepatorenal damage, probably through its anti-oxidative action and its detoxification proccess as well as the potential to minimize the deleterious effects of free radicals on tissue. The protective role of propolis against the ROS induced damages in diabetic mice gives a hope that they may have similar protective action in humans.</p

Antioxidative and antidiabetic effects of naringin and curcumin in vitro and in vivo

The aim of the present study was to assess whether naringin or curcumin can influence oxidative stress induced DNA damage in mice with alloxan-induced diabetes. Naringin or curcumin preparations (50 mg kg-1) were given intraperitoneally for 7 days. The antioxidant capacity of curcumin and naringin in vitro was evaluated using three assays which cover different aspects of antioxidant activity. In order to evaluate the effectiveness of naringin and curcumin in vivo we observed changes in body weight and survival of diabetic mice and used the comet and micronucleus assays. In vitro curcumin showed appreciable antioxidant properties, while naringin was much less effective. Naringin or curcumin administration to diabetic mice resulted in decreased DNA damage in lymphocytes and increased level of DNA damage in liver, kidney and reticulocytes. Administration of naringin and curcumin resulted in significant increase of the body weight and 100% survival of mice.Results suggests that antioxidant activity of naringin and curcumin leads to long time survival of diabetic mice and possible prevention of further oxidative damage, so they could be candidates for antidiabetic agent, but the precise targets of naringin and curcumin in diabetic mice are still to be clarified

Formation of Microalgal Hunting Nets in Freshwater Microcosm Food Web: Microscopic Evidence

The microcosm is a laboratory method frequently used in ecological studies related to population and food web interactions and environmental dynamics. It simultaneously brings into interaction different species in the same controlled laboratory experimental area and provides an opportunity for modeling and reconstruction of relationships in the natural biocenoses and ecosystems. We applied that approach to determine and improve our understanding of predator–prey interactions in different freshwater environments. The inhabitants of the microcosms were isolated endosymbiotic microalga Desmodesmus subspicatus (Chlorophyceae) (Chodat) Hegewald et Schmidt (CZ), green hydras, freshwater turbellarians, and large water fleas. Experiments were performed in five replicates, at 25 °C and 13.5 °C, with fed and hungry predators, respectively. Herein, we proposed a mechanism for microalgal hunting net formation in the freshwater microcosm. Ultrastructural visualization of the endosymbiotic microalgae revealed rod-like structures on the cell wall surface, structures that could possibly fit together and interconnect, suggesting the possibility of microalgal hunting net formation. Interspecific cooperation between isolated microalgae and turbellarians resulted in stronger hunting net formation in preying upon water fleas. This study contributes to the diversity of species interactions and shows the producers as a top link, as opposed to what is generally considered as a basic link in the food web, and presents the microalgae as triggers of the dynamics in the freshwater microcosm

Effects of Norflurazon and UV Radiation on Symbiotic and Free-Living Hydra

In this study, we aimed to document the freshwater symbiotic interactions along with the impact of the abiotic environment and anthropogenic effects on the functionality of freshwater organisms. Symbiotic green hydra (Z) and free-living brown hydra (S), either separately or both species together, were treated with the herbicide norflurazon in concentrations of 2 × 10−6 mol/L (N6) and 2 × 10−7 mol/L (N7) for 72 h. Also, hydras were treated with both norflurazon and UV radiation at a wavelength of 254 nm for 2 min or were irradiated only. The next part of the experiment was performed in the same way but with added suspensions of isolated endosymbiotic alga, free-living alga, or both algae together. Mortality, migration, tentacle and tissue damage, changes in the thickness of the mesoglea of hydras, and clustering of algae were monitored. Green hydra generally showed lower rates of migration, and mortality was observed only in green hydra exposed to UV radiation. Tentacle damage was more pronounced in green hydra and included a specific fork-like structure. The use of cryofixation and TEM enabled us to partly elucidate the effect of clustering of algae. In summary, our study provides new insights into the influence of different environmental stressors and their combination on symbiotic and free-living freshwater hydras and algae and a better understanding of interactions in freshwater ecosystems