Dietary lean red meat and human evolution

Summary Scientific evidence is accumulating that meat itself is not a risk factor for Western lifestyle diseases such as cardiovascular disease, but rather the risk stems from the excessive fat and particularly saturated fat associated with the meat of modern domesticated animals. In our own studies, we have shown evidence that diets high in lean red meat can actually lower plasma cholesterol, contribute significantly to tissue omega-3 fatty acid and provide a good source of iron, zinc and vitamin B₁₂. A study of human and pre-human diet history shows that for a period of at least 2 million years the human ancestral line had been consuming increasing quantities of meat. During that time, evolutionary selection was in action, adapting our genetic make up and hence our physiological features to a diet high in lean meat. This meat was wild game meat, low in total and saturated fat and relatively rich in polyunsaturated fatty acids (PUFA). The evidence presented in this review looks at various lines of study which indicate the reliance on meat intake as a major energy source by pre-agricultural humans. The distinct fields briefly reviewed include: fossil isotope studies, human gut morphology, human encephalisation and energy requirements, optimal foraging theory, insulin resistance and studies on hunter-gatherer societies. In conclusion, lean meat is a healthy and beneficial component of any well-balanced diet as long as it is fat trimmed and consumed as part of a varied diet. Received: 24 February 2000, Accepted: 20 March 2000     

Low level viremia and high CD4% predict normal survival in a cohort of HIV type-2-infected villagers

A community-based study of human immunodeficiency virus type 2 (HIV-2) infection was conducted in a rural village in northern Guinea Bissau, West Africa to assess the relationship between plasma HIV-2 RNA levels, CD4 lymphocyte percentage, and survival over an 8-year period. The cohort of 133 HIV-2-infected individuals and 160 HIV-uninfected controls enrolled in 1991 were followed up at home until 1998. Thirty-one (23%) HIV-2-infected and 24 (16%) HIV-uninfected individuals died over the follow-up period (mortality hazard ratio 1.7, 95% CI 1.0, 2.9; p= 0.06). In HIV-2-infected individuals, the median HIV-2 RNA level was 347 copies/ml and the mean CD4% was 28.6. Both plasma viremia and CD4% were independent predictors of survival, with hazard ratios increasing by 1.6 (95% CI, 1.1, 2.3) for each log(10) increase of plasma viremia and 1.7 (1.1, 2.6) for each 10% decrease of CD4%. Infected subjects with a plasma viral load >or= the median (347 copies/ml) and a CD4% 相似文献   

Working area and angle of attack in three cranial base approaches: pterional, orbitozygomatic, and maxillary extension of the orbitozygomatic approach

OBJECTIVE: This study was designed to quantify the operative exposure obtained in the pterional, orbitozygomatic, and modified orbitozygomatic with maxillary extension surgical approaches. METHODS: The pterional and orbitozygomatic approaches and a variation of the orbitozygomatic osteotomy that included an extra centimeter of bone resection in the inferior direction ("maxillary extension") were performed on cadaveric heads. For each surgical exposure, the working area was determined by using triangles defined with anatomic points. The "angle of attack" of the approaches for the same target point was determined with the use of a robotic microscope. RESULTS: The maximum allowable angle of attack was significantly greater with the orbitozygomatic approach (37.2 +/- 4.7 degrees) than that with the pterional approach (27.1 +/- 4.3 degrees) (P < 0.001). The angle of attack with the maxillary extension (42.0 +/- 4.9 degrees) was significantly greater than that with the orbitozygomatic approach (P < 0.001). The working areas were 281, 343, and 371 mm(2) for the pterional, orbitozygomatic, and maxillary extension approaches, respectively. The orbitozygomatic approach with maxillary extension had a significantly larger working area than the pterional approach (P = 0.011). CONCLUSION: Increments in bony removal open a wider angle in which to work more than they increase the actual amount of working area. Increasing the amount of bone removed by using an orbitozygomatic approach instead of a pterional approach converts a narrow space into a wide portal, allowing surgeons to work closer to the surgical target while decreasing the need for brain retraction. Extending the orbitozygomatic approach into the maxillary region also improves the exposure area and angle, but less significantly.     

Effect of off-pump coronary artery bypass grafting on risk-adjusted and cumulative sum failure outcomes after coronary artery surgery

BACKGROUND AND AIM: We have shown that cumulative sum (CUSUM) failure analysis may be more sensitive than standard statistical methods in detecting a cluster of adverse patient outcomes after cardiac surgical procedures. We therefore applied CUSUM, as well as standard statistical techniques, to analyze a surgeon's experience with off-pump coronary artery bypass grafting (OPCAB) and on-pump procedures to determine whether the two techniques have similar or different outcomes. METHODS: In 320 patients undergoing nonemergent, first time coronary artery bypass grafting, preoperative patient characteristics, rates of mortality and major complications, and ICU and hospital lengths of stay were compared between the on-pump and OPCAB cohorts using Fisher's exact tests and Wilcoxon two sample tests. Predicted mortality and length of stay were determined using previously validated models of the Cardiac Care Network of Ontario. Observed versus expected ratios of both variables were calculated for the two types of procedures. Furthermore, CUSUM curves were constructed for the on-pump and OPCAB cohorts. A multivariable analysis of the predictors of hospital length of stay was also performed to determine whether the type of coronary artery bypass procedure had an independent impact on this variable. RESULTS: The predicted mortality risk and predicted hospital length of stay were almost identical in the 208 on-pump patients (2.2 +/- 3.9%; 8.2 +/- 2.5 days) and the 112 OPCAB patients (2.0 +/- 2.2%; 7.8 +/- 2.1 days). The incidence of hospital mortality and postoperative stroke were 2.9% and 2.4% in on-pump patients versus zero in OPCAB patients (p = 0.09 and 0.17, respectively). Mechanical ventilation for greater than 48 hours was significantly less common in OPCAB (1.8%) than in on-pump patients (7.7%, p = 0.04). The rate of 10 major complications was 14.9% in on-pump versus 8.0% in OPCAB patients (p = 0.08). OPCAB patients experienced a hospital length of stay that was a median of 1.0 day shorter than on-pump patients (p = 0.01). The observed versus expected ratio for length of stay was 0.78 in OPCAB patients versus 0.95 in on-pump patients. On CUSUM analysis, the failure curve in OPCAB patients was negative and was flatter than that of on-pump patients throughout the duration of the study. Furthermore, OPCAB was an independent predictor of a reduced hospital length of stay on multivariable analysis. CONCLUSIONS: OPCAB was associated with better outcomes than on-pump coronary artery bypass despite a similar predicted risk. This robust finding was documented on sensitive CUSUM analysis, using standard statistical techniques and on a multivariable analysis of the independent predictors of hospital length of stay.     

Virtual reality surgical simulation for lower urinary tract endoscopy and procedures

BACKGROUND AND PURPOSE: To provide a realistic experience of lower urinary tract endoscopic procedures, we have developed and continue to expand a computer-based surgical simulator that incorporates a surgical tool interface with anatomic detail and haptic feedback. METHODS: Surface-based geometric data for the lower urinary tract were generated from the National Library of Medicine Visible Human dataset. The three-dimensional texture map of the surface geometry was developed from recorded endoscopic video procedures. Geometry and associated texture maps were rendered in real time using the Silicon Graphics Extreme Impacts program. The surgical interface device incorporated all normal ranges of motion and resistance that occur within an actual operative environment. The hands-on endoscopic device attached to the interface device was provided by Circon-ACMI, Inc. Urologic residents evaluated the program for correlation with actual endoscopic procedures. RESULTS: Texture-mapped digitized images provided a close anatomic similarity to actual videoendoscopic images. Virtual endoscopy of the lower urinary tract was reproducible and closely simulated actual visual and tactile endoscopic experience. CONCLUSIONS: Virtual reality surgical simulation is feasible for a variety of lower urinary tract procedures. This system coordinates visual perception with appropriate haptic feedback in both longitudinal and rotational axes. These types of procedures may be incorporated into future educational experiences for urologists to introduce new techniques and to provide documentation of surgical experience.     

Growth failure,risk of hospitalization and death for children with end-stage renal disease

Growth failure remains a significant problem for children with chronic renal insufficiency and end-stage renal disease (ESRD). We examined whether growth failure is associated with more-frequent hospitalizations or higher mortality in children with kidney disease. We studied data on prevalent United States pediatric patients with ESRD in 1990 who were followed through 1995. Patients were categorized according to the standard deviation score (SDS) of their incremental growth during 1990: severe (<–3 SDS), moderate growth failure (>–3 and <–2 SDS), and normal growth (>–2 SDS). Among 1,112 prevalent pediatric dialysis and transplant patients (<17 years, Tanner I–IV), those with severe and moderate growth failure had higher hospitalization rates {relative risk (RR) 1.14 [95% confidence interval (CI) 1.1, 1.2] and 1.24 [95% CI 1.2, 1.3]} respectively than those with normal growth after adjustment for age, gender, race, cause and duration of ESRD, and treatment modality (dialysis or transplant) in 1990. Kaplan-Meier survival analysis showed 5-year survival of 85% and 90% for patients with severe and moderate growth failure, respectively, compared with 96% for patients with normal growth (P<0.001, log-rank). Cox proportional hazards analysis revealed that those with severe (RR 2.9, 95% CI 1.6, 5.3) and moderate growth failure (RR 2.01, 95% CI 1.1, 3.6) had an increased risk of death compared with youths with normal growth, after adjustment. A higher proportion of deaths in the severe and moderate growth failure groups were attributed to infectious causes (22% and 18.7%, respectively) than in the normal growth group (15.6%). We conclude that growth failure is associated with a more-complicated clinical course and increased risk of death for children with kidney failure. Received: 15 August 2001 / Revised: 14 January 2002 / Accepted: 15 January 2002     

Resolution of papilledema after neurosurgical decompression for primary Chiari I malformation

PURPOSE: To report a causal relationship between Chiari I malformation and its rare, but recognized manifestation of bilateral papilledema. DESIGN: Interventional case series. METHODS: Four adult female patients (mean age, 48, age range 25-59 years) with bilateral papilledema, signs and symptoms of increased intracranial pressure, and cranial magnetic resonance imaging (MRI) evidence of a Chiari I malformation ranging from 7 to 22 mm of tonsillar herniation underwent suboccipital decompression. RESULTS: In all four patients, suboccipital decompression was followed by resolution of bilateral papilledema and signs and symptoms of increased intracranial pressure. CONCLUSION: Patients with bilateral papilledema and presumed pseudotumor cerebri require a cranial MRI to determine if they have a Chiari I malformation, because patients with increased intracranial pressure and papilledema from a Chiari I malformation may benefit from suboccipital decompression.