Virtual anatomy: new opportunities for education research.
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Computer Simulation↗
Biomedical subjects
A Garg
Publications and source records attributed to A Garg.
Familial sudden cardiac death associated with a terminal QRS abnormality on surface 12-lead electrocardiogram in the index case.
A case is presented of an 18-year-old male who had been resuscitated following an episode of sudden death due to ventricular fibrillation. The patient was noted to have an abnormal deflection in the terminal QRS on surface ECG and an abnormal signal-averaged ECG demonstrating a late potential coincident with the terminal QRS abnormality on the ECG. The patient had easily inducible polymorphic ventricular tachycardia during electrophysiologic study, which was suppressed by quinidine but not by procainamide or beta blockers. The surface ECG and signal-averaged ECG also were normalized by quinidine but not by procainamide or beta blockers. The patient had no further arrhythmias on quinidine for 6 years until he inexplicably discontinued his medication and died suddenly shortly thereafter. The present case may represent a unique familial sudden death syndrome or possibly a variant of the sudden death syndrome associated with right bundle branch block and ST elevation in V1 through V3. Currently available data suggest that, in such patients, an implantable cardioverter defibrillator may provide better protection from sudden death than does antiarrhythmic drug therapy.
Adolescent↗
The relationship between low back discomfort ratings and the NIOSH lifting index.
An epidemiological study was performed to evaluate the relation between low-back discomfort ratings and use of the revised NIOSH lifting guide to assess the risk of manual material handling (MMH) tasks. We surveyed 97 MMH workers on site in 15 factories and designed a questionnaire to systematically collect job-related information. Approximately 90% of the workers had suffered various degrees of lower back discomfort, and 80% had sought medical treatment. The survey showed that 42 of the 97 jobs analyzed had a recommended weight limit of 0, which was attributed to either a horizontal distance or a lifting frequency that exceeded the bounds of the NIOSH lifting index. Apparently, the limits for horizontal distance and maximum allowable frequency are too stringent to accommodate many existing MMH jobs. For the remaining 55 jobs, the significant positive correlation obtained between the lifting index and the severity of low-back discomfort suggests that the lifting index is reliable in assessing the potential risk of low-back injury in MMH. These findings provide useful information on the application of the NIOSH lifting guide to the assessment of low-back pain.
Adolescent↗
The key to success: maintaining the long-term health of implants.
During the infancy years of dental implantology, the emphasis for long-term success of osseointegrated implants was the surgical phase of dental implantology. In the years that followed, the emphasis for success had switched from a purely surgical influence to focusing more on the proper fixture placement which would be dictated by the prosthetic and aesthetic needs of each particular case. In more recent years, the dental profession has recognized professional implant maintenance and diligent patient home care as two critical factors for the long-term success of dental implants. The microbiota and clinical presentation of peri-implantitis is the same as periodontitis around a natural tooth.
Dental Implantation, Endosseous↗
Teaching medical students how to break bad news.
UNLABELLED: PROGRAM OBJECTIVE: To teach medical students to break bad news to patients and their families empathically and competently. SETTING: Seven teaching hospitals affiliated with the University of Toronto since 1987. PARTICIPANTS: All medical students in their third preclinical year. PROGRAM: The course presents a 6-point protocol to guide students in breaking bad news and comprises 2 half-day (3-hour) teaching sessions. Each session incorporates a video presentation, a discussion period and small-group teaching, consisting of exercises followed by 4 different role-playing scenarios conducted with the use of standardized patients. The course was evaluated through 2 questionnaires, 1 administered before and 1 after the course, which measured changes in the students' attitude and strategy. Questionnaires were administered during 5 of the years since the course was started. A total of 914 precourse and 503 postcourse questionnaires were completed, of which 359 matched pairs of precourse and postcourse questionnaires were analysed to study any changes due to the course. OUTCOMES: Precourse questionnaires showed that 68% of the students had thought about the task of breaking bad news often or very often. Of the 56% of students who had seen clinicians performing this task, 75% felt that they had seen good examples. The proportion of the students who had a plan for how to conduct such an interview rose from 49% before the course to 92% after it, and the proportion who felt they might be reasonably competent in breaking bad news rose from 23% before the course to 74% after it. CONCLUSIONS: The subject of breaking bad news is important to medical students, and it is practicable to design a course to teach the basic techniques involved. Most students perceive such a course as enjoyable and useful and find that it increases their sense of competence and their ability to formulate a strategy for such situations.
Clinical Competence↗
Relationship of anterior and posterior subcutaneous abdominal fat to insulin sensitivity in nondiabetic men.
Recent studies from our reveal that adipose tissue (AT) in the subcutaneous abdominal region is the most important determinant of peripheral and hepatic insulin sensitivity. Because of different anatomic and physiologic characteristics of anterior and posterior subcutaneous abdominal AT, we investigated the relationship of the masses of each compartment, as determined by magnetic resonance imaging, to insulin sensitivity (using euglycemic hyperinsulinemic glucose clamp technique), and other anthropometric variables. Thirty-four healthy men with varying ranges of obesity were recruited for the study. The mass of posterior subcutaneous abdominal AT was approximately 1.6 times more than that of the anterior compartment, and these masses accounted for 12.9% and 8.2% of the total body fat mass, respectively. All anthropometric variables, including body mass index (BMI), waist-to-hip circumference ratio (WHR), skin-fold thicknesses, and intraperitoneal AT mass were more significantly related to the posterior than the anterior subcutaneous abdominal AT mass. Compared to the anterior compartment mass, the posterior compartment mass displayed stronger relationship with insulin-mediated glucose disposal (Rd) (r = -0.44, p = 0.009, and r = -0.76, p = 0.0001, respectively) as well as with residual hepatic glucose output during the 40 mU.m-2.min-1 insulin infusion (r = 0.39, p = 0.02, and r = 0.53, p = 0.001, respectively). After adjusting for total body fat, the Rd values showed a significant partial correlation with the posterior subcutaneous abdominal AT mass (r = 0.52, p = 0.002). To conclude, posterior subcutaneous abdominal AT mass is more important determinant of peripheral and hepatic insulin sensitivity than the anterior subcutaneous abdominal AT.
Adipose Tissue↗
Evaluation of the impact of employee ergonomics training in industry.
This study examined the effects of three different types of ergonomics training methods upon employee knowledge, attitude and behavior. Employees within intact processing lines (N = 104) were randomized into four groups, one group serving as a control group. Pre- and post-test measures were implemented. Results showed training to have a significant effect upon knowledge of ergonomics. No significant differences were noted among all four groups according to empowerment and human factors measures. Training had a significant impact upon employee's job satisfaction, and the recognition and reporting of health hazards associated with their jobs.
Analysis of Variance↗
Participatory ergonomics in a red meat packing plant. Part II: Case studies.
Three ergonomics-related case studies are presented to demonstrate the problem-solving method used by two participatory ergonomics teams. The problem-solving method was adapted from principles related to quality management (e.g., participation, structure, a scientific approach, and decision by consensus). The first two steps of the problem-solving method were related to identification and evaluation of the problem; the latter three steps were related to solution development, implementation, and evaluation. The problem evaluation process included the collection of background, exposure, and effects data. Solution development following evaluation of the problem started with a brainstorming session, then discussion to select interventions by consensus. The format for presenting the case studies was intended to be concise and visual with the intent of effectively documenting the teams' problem-solving processes.
Ergonomics↗
Prediction of total subcutaneous abdominal, intraperitoneal, and retroperitoneal adipose tissue masses in men by a single axial magnetic resonance imaging slice.
To develop a simplified but accurate method for determining the masses of various abdominal adipose tissue compartments, we studied the predictive value of masses of intraperitoneal, retroperitoneal, and subcutaneous abdominal adipose tissue determined on single axial abdominal magnetic resonance imaging (MRI) slices taken at various intervertebral levels from the 12th thoracic to 1st sacral vertebra (identified on a sagittal section) for the respective total masses of each compartment calculated from contiguous 10-mm thick MRI slices covering the entire abdomen in 49 men (26 without diabetes and 23 with non-insulin-dependent diabetes mellitus). The MRI slice at the intervertebral level between the lumbar (L) 2 and 3 vertebrae showed the highest and most consistent predictive value for all three compartments (R2 = 0.85 for all). Furthermore, compared with other intervertebral levels, the L2-L3 level had a higher amount of intraperitoneal and retroperitoneal adipose tissue mass. We conclude that determining the masses of various abdominal adipose tissue compartments at the L2-L3 intervertebral level by MRI is an acceptably reliable and accurate method for studying abdominal adiposity in men.
Abdomen↗
Serum low-density lipoprotein cholesterol response to modification of saturated fat intake: recent insights.
Two lines of investigation have provided important insights into dietary therapy of hypercholesterolemia. Studies have confirmed the efficacy of the US National Cholesterol Education Program Step II diet in lowering serum LDL-cholesterol concentrations and demonstrate that wide variability exists in responsiveness to this diet. Other studies indicate that, contrary to expectations, cholesterol raising saturated fatty acids are not limited to long-chain saturates, but also include medium-chain and very long-chain saturated fatty acids.
Adult↗
Oxygen free radical scavenging abilities of vitamins C and E, and a grape seed proanthocyanidin extract in vitro.
Proanthocyanidins, a group of polyphenolic bioflavonoids, have been reported to exhibit a wide range of biological, pharmacological and chemoprotective properties against oxygen free radicals. We have assessed the concentration-dependent oxygen free radical scavenging abilities of a grape seed proanthocyanidin extract (GSPE), vitamin C and vitamin E succinate (VES) as well as superoxide dismutase, catalase and mannitol against biochemically generated superoxide anion and hydroxyl radical using a chemiluminescence assay and cytochrome c reduction. A concentration-dependent inhibition was demonstrated by GSPE. At a 100 mg/l concentration, GSPE exhibited 78-81% inhibition of superoxide anion and hydroxyl radical. Under similar conditions, vitamin C inhibited these two oxygen free radicals by approximately 12-19%, while VES inhibited the two radicals by 36-44%. The combination of superoxide dismutase and catalase inhibited superoxide anion by approximately 83%, while mannitol resulted in an 87% inhibition of hydroxyl radical. The results demonstrate that GSPE is a more potent scavenger of oxygen free radicals as compared to vitamin C and VES.
Anthocyanins↗
Decoherence in Ion Trap Quantum Computers.
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Journal Article↗
Inseparable iduronic acid-containing proteoglycan PG(IdoA) preparations of human skin and post-burn scar tissues: evidence for elevated levels of PG(IdoA)-I in hypertrophic scar by N-terminal sequencing.
Hypertrophic scarring is characterized by disordered collagen fibrils. In order to determine whether this is, in part, a result of changes in the population of proteoglycans that are thought to be involved in regulation of collagen fibril formation, we have compared PGs from post-burn normal and hypertrophic scar tissue, as well as from human dermis and epidermis. Efforts to separate the two major iduronic acid-containing proteoglycans, decorin [PG(IdoA)-II] and biglycan [PG(IdoA)-I], for quantitation were not successful. The different N-terminal sequences of these two iduronic acid-containing proteoglycans PG(IdoA-I and -II were utilized to estimate the relative amounts in the above PG(IdoA) preparations. Normal scar, dermis and epidermis were all found to contain primarily decorin with low (< 10%) levels of biglycan relative to decorin. In contrast, iduronic acid-containing proteoglycans from hypertrophic scar were found to be approximately 30% biglycan [PG(IdoA)-I]. This may be a proximal cause of altered collagen fibrils, or may result in alterations in the sequestration of growth factors, which then results in changes in collagen that effect the appearance of the scar. 1966 Elsevier Science Ltd.
Amino Acid Sequence↗
Does macroscopic quantum coherence occur in ferritin?
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Chemical Phenomena↗
Mermin and Garg reply.
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Journal Article↗
Surface superconductivity and Hc3 in UPt3.
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Journal Article↗
Use of participatory ergonomics teams to address musculoskeletal hazards in the red meat packing industry.
Participatory ergonomics teams from two departments of a pork slaughtering plant analyzed musculoskeletal hazards and proposed ergonomics solutions for several jobs in the plant. The jobs were targeted based on association with a large number of injuries, one or more particularly severe injuries, high workers' compensation expenses, and/or high turnover plus absence of obvious solutions to abate the hazards. The teams used a structured problem-solving method that was generally derived from principles associated with quality improvement processes. Workers performing the targeted jobs were involved in the problem-solving process, even if they were not members of the team. The effectiveness of each team was assessed and compared in terms of the number of problem jobs addressed and feedback from team members. One team addressed all nine of its targeted jobs; the other team addressed eight of 12 targeted jobs. Feedback from team members regarding their teams' methods and performance was generally favorable. The major obstacle to effective team functioning in this project was the scheduling of meetings. There were also some obstacles related to team leadership. Overall, this project demonstrated that the use of participatory ergonomics teams that rely on structured problem-solving methods are able to work effectively to address musculoskeletal hazards, especially related to the upper extremities, in the red meat packing industry.
Animals↗
Myelotoxic effects of the bifunctional alkylating agent bizelesin on human, canine and murine myeloid progenitor cells.
Bizelesin is a potent synthetic derivative of the anticancer agent CC-1065 that preferentially alkylates and binds the minor grove of DNA. Preclinical animal studies have found bizelesin to be more toxic to beagle dogs than to rodents and that myelosuppression was the dose-limiting toxicity. This toxicity was dose- and time-dependent in all species. Due to the significant difference in the in vivo myelotoxicity between species, it was important to determine which one most closely resembles humans on a pharmacodynamic basis. Therefore, hematopoietic clonal assays were utilized to evaluate the effects of bizelesin on granulocyte-macrophage (CFU-gm) colony formation. Marrow cells were exposed in vitro to bizelesin (0.001-1000 nM) for 1 or 8 h and then assayed for colony formation. There was a 3-log difference in drug concentration at which 100% colony inhibition occurred (1 or 8 h) for murine CFU-gm versus human or canine CFU-gm. The IC70 value after an 8-h bizelesin exposure for human CFU-gm (0.006 +/- 0.002 nM) was 2220-times lower than for murine CFU-gm (13.32 +/- 8.31 nM). At any given concentration, an 8 h drug exposure resulted in greater colony inhibition than a 1 h exposure for all species (P < 0.05). Increasing exposure time from 1 to 8 h increased toxicity to human and canine CFU-gm much more than to murine CFU-gm. The clinically formulated drug solution was a more potent inhibitor of human colony formation than drug dissolved in DMSO. The IC70 value after a 1-h exposure was 1.7 times lower for human CFU-gm with formulated bizelesin (0.106 +/- 0.105 nM) than bulk drug in DMSO (0.184 +/- 0.044 nM). The results of these in vitro clonal assays were qualitatively consistent with those seen in whole animal studies, suggesting that bizelesin will be a potent myelosuppressive agent in the clinic. Since the dose-limiting toxicity in preclinical models is myelosuppression and the in vitro sensitivity of human and canine CFU-gm is similar, the canine maximum tolerated dose (MTD) is better than the murine MTD to determine a safe starting dose for phase I clinical trials.
Animals↗