PubMed · 8372301
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B Ghavami. 1993. [Celioscopic surgery: current possibilities].. https://pubmed.ncbi.nlm.nih.gov/8372301/
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In Drosophila the precursors of the adult musculature arise during embryogenesis. These precursor cells have been termed Persistent Twist Cells (PTCs), as they continue to express the transcription factor Twist after that gene ceases expression elsewhere in the mesoderm. In the larval abdomen, the PTCs are associated with peripheral nerves in stereotypic ventral, dorsal, and lateral clusters, which give rise, respectively, to the ventral, dorsal, and lateral muscle fiber groups of the adult. We tested the developmental potential of the PTCs by using a microbeam laser to ablate specific clusters in larvae. We found that the ablation of a single segmental PTC cluster does not usually result in the deletion of the corresponding adult fibers of that segment. Instead, normal or near normal numbers of adult fibers can form after the ablation. Examination of pupae following ablation showed that migrating PTCs from adjacent segments are able to invade the affected segment, replenishing the ablated cells. However, the ablation of homologous PTCs in multiple segments does result in the deletion of the corresponding adult muscle fibers. These data indicate that the PTCs in an abdominal segment can contribute to the formation of muscle fibers in adjacent abdominal segments, and thus are not inherently restricted to the formation of muscle fibers within their segment of origin.
CONTEXT: Obesity is a well-established risk factor for coronary heart disease (CHD), but whether regional fat distribution contributes independently to risk remains unclear. OBJECTIVE: To compare waist-hip ratio (WHR) and waist circumference in determining risk of CHD in women. DESIGN AND SETTING: Prospective cohort study among US female registered nurses participating in the Nurses' Health Study conducted between 1986, when the nurses completed a questionnaire, and follow-up in June 1994. PARTICIPANTS: A total of 44702 women aged 40 to 65 years who provided waist and hip circumferences and were free of prior CHD, stroke, or cancer in 1986. MAIN OUTCOME MEASURES: Incidence of CHD (nonfatal myocardial infarction or CHD death). RESULTS: During 8 years of follow-up 320 CHD events (251 myocardial infarctions and 69 CHD deaths) were documented. Higher WHR and greater waist circumference were independently associated with a significantly increased age-adjusted risk of CHD. After adjusting for body mass index (BMI) (defined as weight in kilograms divided by the square of height in meters) and other cardiac risk factors, women with a WHR of 0.88 or higher had a relative risk (RR) of 3.25 (95% confidence interval [CI], 1.78-5.95) for CHD compared with women with a WHR of less than 0.72. A waist circumference of 96.5 cm (38 in) or more was associated with an RR of 3.06 (95% CI, 1.54-6.10). The WHR and waist circumference were independently strongly associated with increased risk of CHD also among women with a BMI of 25 kg/m2 or less. After adjustment for reported hypertension, diabetes, and high cholesterol level, a WHR of 0.76 or higher or waist circumference of 76.2 cm (30 in) or more was associated with more than a 2-fold higher risk of CHD. CONCLUSIONS: The WHR and waist circumference are independently associated with risk of CHD in women.
STUDY DESIGN: Intramuscular pressures in both Erectors Spinae and intra-abdominal pressures were measured during different holding tasks. OBJECTIVES: To investigate the potential for using intramuscular pressure measurements in both Erectors Spinae to better quantitate the role of muscles during different lifting tasks in vivo. SUMMARY OF BACKGROUND DATA: Intramuscular pressure and intra-abdominal pressure were measured previously under isometric and dynamic conditions. However, no previous study systematically has addressed the relation between intramuscular and intra-abdominal pressures and different loads, tasks, and postures. METHODS: Intramuscular and intra-abdominal were measured simultaneously with microtip pressure transducers in 10 healthy volunteers performing 24 different static holding tasks. Tasks included different weights (10 kg and 20 kg), postures (squat or back lift), and positions of the weight. RESULTS: Intramuscular pressures were dependent on posture. Kyphotic back posture produced intramuscular pressures of 120-130 mm Hg, compared with the 10-25 mm Hg produced when volunteers were in the erect position (P < 0.001). Holding a 10-kg weight at the thighs close to the body produced significantly (P < 0.001) lower intramuscular pressures (25-32 mm Hg) than that produced by holding it 25 cm in front of the body (47-56 mm Hg). In all tasks, intramuscular pressures were significantly higher with the 20-kg weight than with the 10-kg weight (P < 0.001). Highest values (> 300 mm Hg) were measured when the 20-kg weight was held in the kyphotic posture above the floor and 25 cm away from the body. CONCLUSIONS: Intramuscular pressure measurements in the erector spinae seem to be a valuable tool for quantitating the role of back muscles during different lifting tasks.