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Biomedical subjects

J Pope

Publications and source records attributed to J Pope.

31 records · Page 2Linked to original sources
PubMed1990

Retinal pigment epithelial tear associated with subretinal hemorrhage: a case report.

Tears of the retinal pigment epithelium (RPE) are a recognized complication of pigment epithelium detachments associated with age-related macular degeneration (ARMD). The RPE tears are often associated with a poor visual prognosis and typically do not occur with subretinal hemorrhage. We report the case of a 76-year-old man with ARMD who developed an RPE tear associated with subretinal hemorrhage, without a demonstrable subretinal neovascular membrane. Temporally, there was a marked decrease in his vision that returned to his earlier baseline visual acuity over the course of six months of observation.

Aged↗
PubMed1988

Comparison of isokinetic and isoinertial lifting tests as predictors of maximal lifting capacity.

This study compared the relationship between isokinetic lifting test (ILT) performance and a maximal operational lifting test (OLT) with that between an isoinertial progressive lifting test (PLT) and OLT. Fifty subjects performed the ILT, PLT and OLT after familiarization trials. OLT was defined as the weight of the heaviest crate that could be lifted to 1.34 m with a progressive, incremental test. ILT performance was the force generated during a single maximal simulated lift on an isokinetic dynamometer. PLT performance was the maximal weight lifted to 1.52 m with a progressive, incremental protocol on a weight stack. OLT was highly correlated with ILT (r = 0.96) and PLT (r = 0.97); the standard error was similar for both linear regression equations. The results demonstrate that a single maximal voluntary lift on an isokinetic dynamometer is as good a predictor of OLT as in the PLT presently used in military recruit centers.

Female↗
PubMed1988

Electro-mechanical response times and muscle strength after sleep deprivation.

This study examined the effect of 60 h of sleep deprivation (SD) on electromechanical response times (EMRT), maximal voluntary isometric contraction (MVC), rate of force development (RFD), and times required to reach various percentages of MVC, during a maximal voluntary isometric contraction of both the forearm flexors and leg extensors. Eleven male subjects were either sleep deprived for 60 h (E) or performed similar daily activities and slept 7 h per night (C). Performance variables were evaluated at the same time intervals during both conditions. No significant differences were observed between the E and C conditions for EMRT (pre-motor time, electro-mechanical delay, total reaction time) or muscular performance (MVC, RFD). The results suggest that subjects who have undergone 60 h of SD can react as fast, and with as much force, as those who have had 7 h of sleep per night.

Adult↗
PubMed1987

Effects of hydraulic resistance circuit training on physical fitness components of potential relevance to +Gz tolerance.

Recent studies carried out in the United States and Sweden have demonstrated that strength training can improve +Gz acceleration tolerance. Based on these findings, the Canadian Forces have introduced a training program for aircrew of high performance aircraft. This report describes the changes in physical fitness components considered relevant to +Gz tolerance after 12 weeks of training with this program. Prior to beginning training, 45 military personnel were tested, but only 20 completed a minimum of 24 training sessions. The following variables were measured in these 20 subjects before and after training: maximal strength of several large muscle groups during isokinetic contractions, maximal aerobic power and an endurance fitness index, maximal anaerobic power, anthropometric characteristics, and maximal expiratory pressure generated during exhalation. Training involved hydraulic resistance circuit training 2-4 times/week. The circuit consisted of 3 consecutive sets at each of 8 stations using Hydra-Gym equipment. The exercise:rest ratio was 20:40 s for the initial 4 training weeks and was then changed to 30:50. After training the changes in anthropometric measurements suggested that lean body mass was increased. Small, but significant, increases were also measured in muscle strength during bench press, biceps curls, squats, knee extension, and knee flexion. Neither maximal anaerobic power (i.e. muscular endurance) nor maximal expiratory pressure were changed after the training. Indices of endurance fitness were also increased in the present study. The relatively small increases in strength are probably due to the design of the exercise:rest ratio which resulted in improved strength and aerobic fitness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Correlates of success of graduates of a coordinated undergraduate program.

Significant relationships were identified between dietetic student characteristics, several predictors of success, and success variables. Grades earned during the junior and senior college years were positively correlated, and the number of examinations on which the student failed to score 80% were negatively correlated with academic success in the preprofessional phase of the CUP. No relationship between professional behavior scores and any of the predictors was identified. Success in the registration examination for dietitians was positively correlated with both course grades and ACT scores; however, registration examination scores were not correlated with employers' assessments of the graduates' competence. Number of salary increases was significantly, positively related to extracurricular college activities, work experience, mathematics ACT scores, and preprofessional science grades. ACT scores, preprofessional science grades, and work experience prior to admission to the professional phase of the CUP were positively related to obtaining advanced degrees. Advanced degrees were also significantly, positively correlated with continuing education and dietetic association activities. The amount of professional and community involvement was best predicted from college extracurricular activities. Of all the predictors studied, preprofessional science grades and overall GPA were significantly, positively correlated with more success measures than any other predictors.

Achievement↗
PubMedDate not supplied

Effect of preinduction specific growth rate on recombinant alpha consensus interferon synthesis in Escherichia coli.

The effect of preinduction specific growth rate on the yield of recombinant alpha consensus interferon in Escherichia coli K-12 was investigated. The cells used in the investigation contain a temperature-sensitive, walkaway plasmid bearing an insert that codes for alpha consensus interferon. Transcription of the recombinant gene is controlled by a lambda repressor/pL promoter system. The lambda promoter is regulated by the temperature-sensitive gene cI857 at 30 degrees C, but at 42 degrees C the promoter is derepressed. The cells were grown under glucose-limited conditions in a chemostat at pH 7 and 30 degrees C. Once steady state was achieved, the vessel temperature was raised to 42 degrees C and a fed-batch mode was initiated. Six dilution rates ranging from 0.025/h to 0.2/h were investigated. Cell dry weight, alpha consensus interferon content, glucose concentration, acetate concentration, and plasmid stability were measured. At each dilution rate, the expression level of alpha consensus interferon (g/g of cell dry wt) reached its maximum value approximately 3 h after induction. In addition, the expression level of alpha consensus interferon increases 4-fold as the dilution rate prior to induction is increased from 0.025/h to 0.2/h. Consequently, the expression of recombinant protein produced by E. coli is dependent on the preinduction specific growth rate.

Acetates↗
PubMedDate not supplied

Effect of preinduction specific growth rate on secretion of granulocyte macrophage colony stimulating factor by Escherichia coli.

The effect of preinduction specific growth rate on the rate of synthesis and processing of granulocyte macrophage colony stimulating factor (GMCSF) secreted by Escherichia coli was investigated. A chemostat was used to explore preinduction growth rates ranging from 0.038 to 0.2/h. The maximum yields of both total GMCSF and processed GMCSF were found to occur at a preinduction growth rate of 0.13/h. It was also discovered that if the postinduction feed rate is reduced at a preinduction growth rate near 0.13/h, then the same amount of processed GMCSF is formed, but no unprocessed GMCSF is produced. It was hypothesized that the rate of synthesis of total GMCSF increases with an increased preinduction specific growth rate, but translocation across the cytoplasmic membrane and processing is rate-limiting. Increased degradation of GMCSF during induction at higher preinduction specific growth rates decreased the amount of GMCSF produced.

Cell Division↗
PubMedDate not supplied

Growth kinetics of Escherichia coli and expression of a recombinant protein and its isoforms under heat shock conditions.

Preinduction culture conditions were found to have significant impact on the expression and post-translational modification of a recombinant human protein in Escherichia coli under heat shock conditions (30 to 42 degrees C shift). Higher preinduction growth rates (micrograms) favored better cell viability, greater cell mass yields, and increased cloned gene expression during induction. Formation of recombinant protein isoforms (those containing N epsilon-modified lysine residues) exhibited an increasing trend with increasing micrograms. The different extents of post-translational modifications were suspected to be linked to the different concentrations of certain heat shock protein chaperones resulting from different micrograms. In view of the extensive involvement of E. coli heat shock proteins in cellular activities-including the synthesis, processing, modification, and degradation of proteins-at elevated temperatures, it is believed that micrograms dictated the cellular resources available for synthesizing the heat shock proteins required for cell survival, which in turn determined the ability of the cells to respond to the heat shock. With a higher micrograms both the synthesis of host proteins (as indicated by cell growth and survival) and the cloned gene expression were enhanced. The results demonstrate that there exists an intermediate micrograms for optimum production of the unmodified foreign protein in a heat shock environment. More importantly, they also illustrate the feasibility of improving the recombinant protein homogeneity in fermentation, thereby facilitating downstream processing.

Bioreactors↗