Procrastination among basic science undergraduate medical students in a Caribbean medical school.

This article was migrated. The article was marked as recommended. PURPOSE: The study was conducted to study procrastination behavior among basic science undergraduate medical students using the previously validated procrastination assessment scale students (PASS). Frequency of and reasons for procrastination were compared among different subgroups of respondents. METHODS: The study was conducted during the first two weeks of February 2017 using PASS. Gender, nationality and semester of study of the respondents were noted. PASS explores areas of and frequency of procrastination, reasons for procrastination and interest in changing the behavior. The frequency of procrastination, fear of failure, risk aversiveness, laziness and rebellion against control scores were compared among different subgroups using appropriate statistical tests. RESULTS: A total of 107 students (84.9%) participated in the study. The mean frequency of procrastination score was 32.9 (maximum score 60). The score was significantly correlated with the respondents' gender. With regard to the percentage of students who nearly always or always procrastinated on a task, the percentages with regard to completing assignments, studying for exams, completing reading assignments, academic administrative tasks, attendance tasks and school activities in general were 25.2, 19.7, 25.2, 19.6, 18.7 and 17.7. The mean score for 'fear of failure' and 'aversiveness of task' as described by Solomon and Rothblum was 2.29 and 2.83. The mean scores for fear of failure, risk taking, and laziness were 26.17, 13.76 and 14.32. The median rebellion against control score was 6. Risk taking score was higher among respondents of other nationalities compared to Americans. CONCLUSIONS: Procrastination was regarded as a greater problem with regard to studying for exams and completing reading assignments and preparing for problem-based learning sessions. Only 42% of students were interested in attending a program to overcome procrastination. Similar studies among students during the clinical years are required. A study correlating self-reported procrastination with behavior can be carried out. Procrastination can also be studied in other offshore, Caribbean medical schools.

Site directed mutagenesis of Drosophila flightin disrupts phosphorylation and impairs flight muscle structure and mechanics.

Flightin is a myosin rod binding protein that in Drosophila melanogaster is expressed exclusively in the asynchronous indirect flight muscles (IFM). Hyperphosphorylation of flightin coincides with the completion of myofibril assembly and precedes the emergence of flight competency in young adults. To investigate the role of flightin phosphorylation in vivo we generated three flightin null (fln(0)) Drosophila strains that express a mutant flightin transgene with two (Thr158, Ser 162), three (Ser139, Ser141, Ser145) or all five potential phosphorylation sites mutated to alanines. These amino acid substitutions result in lower than normal levels of flightin accumulation and transgenic strains that are unable to beat their wings. On two dimensional gels of IFM proteins, the transgenic strain with five mutant sites (fln(5STA)) is devoid of all phosphovariants, the transgenic strain with two mutant sites (fln(2TSA)) expresses only the two least acidic of the nine phosphovariants, and the transgenic strain with three mutant sites (fln(3SA)) expresses all nine phosphovariants, as the wild-type strain. These results suggest that phosphorylation of Thr158 and/or Ser162 is necessary for subsequent phosphorylation of other sites. All three transgenic strains show normal, albeit long, IFM sarcomeres in newly eclosed adults. In contrast, sarcomeres in fully mature fln(5STA) and fln(2TSA) adults show extensive breakdown while those in fln(3SA) are not as disordered. The fiber hypercontraction phenotype that characterizes fln(0) is fully evident in fln(5STA) and fln(2TSA) but partially rescued in fln(3SA). Mechanics on skinned fibers from newly eclosed flies show alterations in viscous modulus for fln(5STA) and fln(2TSA) that result in a significant reduction in oscillatory power output. Expression of fln(5STA) and fln(2TSA), but not fln(3SA), in a wild-type (fln(+)/fln(+)) background resulted in a dominant negative effect manifested as flight impairments and hypercontracted IFM fibers. Our studies indicate that Thr158 and/or Ser162 are (is) indispensable for flightin function and suggest that phosphorylation of one or both residues fulfills an essential role in IFM structural stability and mechanics.

Flight muscle properties and aerodynamic performance of Drosophila expressing a flightin transgene.

Flightin is a multiply phosphorylated, myosin-binding protein found specifically in indirect flight muscles (IFM) of Drosophila. A null mutation in the flightin gene (fln(0)) compromises thick filament assembly and muscle integrity resulting in muscle degeneration and lost of flight ability. Using P-element-mediated transformation with the full-length flightin gene driven by the Actin88F promoter, we have achieved rescue of all fln(0)-related ultrastructural and functional defects of the IFM. Transgenic P{fln(+)}fln(0) 'rescued' flies have fewer thick filaments per myofbril than wild-type flies (782+/-13 vs 945+/-9) but have otherwise normal IFM. Transgenic P{fln(+)}fln(+) 'tetraploid' flies have a normal number of thick filaments. The flightin protein levels in both transgenic strains are similar to wild type. By contrast, flightin levels are reduced in a myosin heavy chain tetraploid strain that produces excess myosin and excess thick filaments. These results suggest that regulation of flightin protein level is independent of gene copy number and that the number of thick filaments assembled per myofibril is influenced independently by myosin and flightin expression. We measured mechanical properties of IFM skinned fibers by sinusoidal analysis and found no significant differences in active viscoelastic properties of flightin-rescued and tetraploid transgenic flies vs wild type. The ability of the fln(+) transgene to overcome deficits in dynamic stiffness and power output in fln(0) suggest that the flightin protein contributes directly to fiber stiffness and stretch activation. However, flight parameters at maximum locomotor capacity, measured in a virtual reality flight simulator, are slightly compromised for both transgenic strains. P{fln(+)}fln(0) and P{fln(+)}fln(+) flies generated enough flight force to sustain hovering flight but showed reduced capability to produce forces in excess of hovering flight force. Both strains showed reductions in stroke frequency but only P{fln(+)}fln(+) showed reductions in stroke amplitude. Muscle and aerodynamic efficiency are similar among the two transgenic strains and wild type. These results illustrate the importance of flightin in flight muscle development and function.