Search

BACKGROUND Aquatic species in several clades possess cement glands producing adhesive secretions of various strengths. In vertebrates, transient adhesive organs have been extensively studied in Xenopus laevis, other anurans, and in several fish species. However, the development of these structures is not fully understood. RESULTS Here, we report on the development and functional morphology of the adhesive gland of a giant danio species, Devario malabaricus. We found that the gland is localized on the larval head, is composed of goblet-like secretory cells framed by basal, bordering, and intercalated apical epithelial cells, and is innervated by the trigeminal ganglion. The gland allows nonswimming larvae to adhere to various substrates. Its secretory cells differentiate by 12 hours postfertilization and begin to disappear in the second week of life. Exogenous retinoic acid disrupts the gland's patterning. More importantly, the single mature gland emerges from fusion of two differentiated secretory cells fields; this fusion is dependent on nonmuscle myosin II function. CONCLUSIONS Taken together, our studies provide the first documentation of the embryonic development, structure, and function of the adhesive apparatus of a danioninae. To our knowledge, this is also the first report of a cement gland arising from convergence of two bilateral fields.

The purpose of this study was to examine the effect of three bone vibrator coupling methods on the neonate auditory brainstem response (ABR).A repeated measures design was employed. Three coupling techniques were utilised (i.e. hand-held, hand-held applied force gauge and elastic band). ABRs were evoked with a bone-conducted 30 dB nHL 4000 Hz CE-Chirp octave band stimulus. A temporal bone area supero-posterior auricular position for bone vibrator placement was utilised.Twenty-six healthy full-term neonates participated.Replicated ABRs were recorded from all neonates for each coupling method. There was a statistically significant effect of coupling on wave V latency (p 0.001) and amplitude (p 0.001). There was no statistical difference between the elastic band and the hand-held force gauge coupling for wave V latency and amplitude (p 0.05). However, the hand-held coupling method produced significantly longer wave V latency and smaller amplitude versus the elastic band and hand-held force gauge (p 0.001).Bone vibrator coupling method affects the neonate ABR. Clinicians should be consistent with the choice of coupling while delivering controlled bone-conducted stimuli in ABR assessments in neonates and infants.

Giant danios (genus Devario), like zebrafish, are teleosts belonging to the danioninae subfamily of cyprinids. Adult giant danios are used in a variety of investigations aimed at understanding cellular and physiological processes, including heart regeneration. Despite their importance, little is known about development and growth in giant danios, or their cardiac and coronary vessels development. To address this scarcity of knowledge, we performed a systematic study of a giant danio (Devario malabaricus), focusing on its cardiac development, from the segmentation period to ten months post-fertilization. Using light and scanning electron microscopy, we documented that its cardiovascular development and maturation proceed along well defined dynamic and conserved morphogenic patterns. The overall size and cardiovascular expansion of this species was significantly impacted by environmental parameters such as rearing densities. The coronary vasculature began to emerge in the late larval stage. More importantly, we documented two possible loci of initiation of the coronary vasculature in this species, and compared the emergence of the coronaries to that of zebrafish and gourami. This is the first comprehensive study of the cardiac growth in a Devario species, and our findings serve as an important reference for further investigations of cardiac biology using this species.

Academic dishonesty, including cheating and plagiarism, is on the rise in colleges, particularly among engineering students. While students decide to engage in these behaviors for many different reasons, academic integrity training can help improve their understanding of ethical decision making. The two studies outlined in this paper assess the effectiveness of an online module in increasing academic integrity among first semester engineering students. Study 1 tested the effectiveness of an academic honesty tutorial by using a between groups design with a Time 1- and Time 2-test. An academic honesty quiz assessed participants' knowledge at both time points. Study 2, which incorporated an improved version of the module and quiz, utilized a between groups design with three assessment time points. The additional Time 3-test allowed researchers to test for retention of information. Results were analyzed using ANCOVA and t tests. In Study 1, the experimental group exhibited significant improvement on the plagiarism items, but not the total score. However, at Time 2 there was no significant difference between groups after controlling for Time 1 scores. In Study 2, between- and within-group analyses suggest there was a significant improvement in total scores, but not plagiarism scores, after exposure to the tutorial. Overall, the academic integrity module impacted participants as evidenced by changes in total score and on specific plagiarism items. Although future implementation of the tutorial and quiz would benefit from modifications to reduce ceiling effects and improve assessment of knowledge, the results suggest such tutorial may be one valuable element in a systems approach to improving the academic integrity of engineering students.

Millions of people worldwide are exposed to arsenic (As), a toxicant which increases the risk of various cancers, cardiovascular disease and several other health problems. Arsenic is a potent endocrine disruptor, including of the estrogen receptor. It was recently shown that environmental estrogen-receptor disruptors can affect the signaling of mast cells, which are important players in parasite defense, asthma and allergy. Antigen (Ag) or allergen crosslinking of IgE-bound receptors on mast cells leads to signaling, culminating in degranulation, the release of histamine and other mediators. Because As is an endocrine disruptor and because endocrine disruptors have been found to affect degranulation, here we have tested whether sodium arsenite affects degranulation. Using the rat basophilic leukemia (RBL) mast cell model, we have measured degranulation in a fluorescence assay. Arsenic alone had no effect on basal levels of degranulation. However, As strongly inhibited Ag-stimulated degranulation at environmentally relevant concentrations, in a manner that is very dependent on concentrations of both As and Ag. The concentrations of As effective at inhibiting degranulation were not cytotoxic. This inhibition may be a mechanism underlying the traditional Chinese medicinal use of As to treat asthma. These data indicate that As may inhibit the ability of humans to fight off parasitic disease.