ABSTRACT
In order to increase the number of practical and discussion classes offered to students in the traditional-curriculum scenario, while decreasing the lecture-based ones and to create an online community to share knowledge on surgery, we developed and assessed the first online course for undergraduate medical students on experimental surgery at the Federal University of Sao Paulo-UNIFESP, Brazil. The purposes of the present study are: describe and discuss the process and the lessons learned involved in developing an undergraduate web-based course and analyze the students' attitude towards this educational environment. A group of medical students was taught online during 5 weeks on the theory of experimental surgery through video quizzes, required readings, collaborative activities using discussion board and asynchronous communication. The students' knowledge gain, their web session variables and the results of the course evaluation were used to support our study. The students have significantly improved their knowledge on experimental surgery after the course. Among factors in the online course that could possibly have contributed to this gain, the interactive activities (video quizzes), key element in our online material, seemed to be promising for candidates. The evaluation results demonstrated high levels of course functionality, effectiveness of its online content and acceptance among medical students. This study indicated that a web-based course for undergraduate students may be successfully developed and implemented in medical settings and the students seem to be quite supportive. We encourage undergraduate medical learning strategies involving the Web.
Subject(s)
Education, Medical, Undergraduate/trends , General Surgery/economics , Internet , Adult , Attitude , Curriculum , Education, Medical, Undergraduate/standards , Humans , Knowledge , Program DevelopmentABSTRACT
Benzhydrylamine-resin (BHAR), a copolymer of styrene-divinylbenzene containing phenylmethylamine groups, used as solid support for peptide synthesis, was examined regarding physicochemical and anion exchanger chromatographic properties. The greater the ionic strength of the medium the poorer the solvation of beads. This effect is less pronounced the higher the amino group content of BHAR. The BHAR chromatographic behavior was compared with commercial cationic resins in columns of constant cation binding capacity. Three negatively charged heparan sulfate disaccharides were successfully purified in a 2.4 mmol/g BHAR that showed as good or better anion exchange performance than classical tertiary or quaternary amino group-containing resins. The BHAR chromatographic resin exclusion limit was estimated to be 30 kDa based on purification experiments of heparins of different molecular weight.
Subject(s)
Anion Exchange Resins/chemistry , Benzhydryl Compounds/chemistry , DEAE-Dextran/analogs & derivatives , Amines/chemistry , Chromatography, Ion Exchange/methods , DEAE-Dextran/chemistry , Disaccharides/isolation & purification , Heparin/analogs & derivatives , Molecular Weight , Osmolar Concentration , Solvents/chemistryABSTRACT
In the present investigation, in order to dispute the rational criticism against the presence of proteolytic enzymes in the electrostimulated venom obtained from spiders of the genus Loxosceles, as a consequence of contamination with abdominal secretions, venoms of L. intermedia and L. laeta were directly collected from venom glands by microdissection and gentle homogenization. Gel electrophoresis stained by silver method carried out to compare L. intermedia electrostimulated venom and venom gland extract demonstrated no significant differences in protein profile. Zymogram analysis of L. intermedia venom gland extract detected a gelatinolytic activity in the 32-35 kDa region. The inhibitory effect of 1,10-phenanthroline on this proteolytic activity further supported its metalloprotease nature. In proteolytic digestion experiments L. intermedia venom gland extract was also able to cleave purified fibronectin and fibrinogen. The inhibitory effect of 1,10-phenanthroline on these degrading activities confirmed the presence of metalloproteases in the venom. In addition, when purified fibrinogen was incubated with L. intermedia abdominal extract, the fibrinogenolysis was completely different, generating low mass fragments that ran away from the gel, a proteolytic event not blocked by 1,10-phenanthroline. Zymogram experiments using L. laeta venom gland extracts further detected a gelatinolytic band at 32-35 kDa, also inhibited by 1,10-phenanthroline, confirming the presence of metalloproteases in both species.
