Spatial orientation in virtual environment compared to real-world.

Virtual reality (VR) is popular across many disciplines and has been increasingly used in sports as a training tool lately. However, it is not clear whether the spatial orientation of humans works equally within VR and in the real-world. In this paper, two studies are presented, in which natural body movements were allowed and demanded. Firstly, a series of verbal and walking distance estimation tests were conducted in both the virtual and the real environment. The non-parametric Friedman test with pairwise comparisons showed no significant differences neither in verbal nor in walking distance estimations between the conditions (all p > 0.05). However, shorter distances (0.9-1.5 m) were estimated more precisely than larger distances (2.6-2.8 m) in both environments. Secondly, a self-developed route recall test to examine the spatial orientation was performed in the virtual and the real environment. The participants visually perceived the predefined route and were instructed to follow these routes with their eyes blindfolded and afterward to return to their starting position. Between the ending and the starting position, no difference between the two environments was observed (p > 0.05). Based on these two studies, the performance of the human spatial orientation preliminarily verified the same in a virtual and real environment.

Physical activity, biliary lipids, and gallstones in obese subjects.

OBJECTIVE: Gallstone disease is a major source of morbidity in the US. Reduced physical activity has been shown to be a risk factor for gallstone formation in recent studies; however, the mechanisms to explain how physical activity may protect against gallstone formation have not been well elucidated. We investigated the relationships between physical activity, biliary lipids, and gallstone disease. METHODS: Three types of habitual physical activity (work, sport, and leisure time), biliary lipids, and serum lipids were estimated or measured in 53 obese subjects undergoing gastric bypass surgery. These physical activities were defined as activity at work, sport activity during leisure time, and activity during leisure time excluding sports, respectively. RESULTS: We found that sport activity but not work and leisure time activities was inversely associated with gallstone disease. Lower levels of biliary bile salts and percent biliary bile salts (expressed in percentage of total biliary lipids) and higher levels of percent cholesterol were also found to be associated with gallstone disease. A lower level of sport activity appeared to be associated with higher levels of biliary cholesterol, percent biliary cholesterol, and serum triglycerides. CONCLUSION: Our findings demonstrate that low levels of physical activity are associated with gallstone formation. Our study also suggests that a possible mechanism for the protective effect of physical activity on gallstone formation is the lowering of biliary cholesterol levels, thus preventing cholesterol from precipitating in the bile. In addition, our data suggest that sport activity is a more effective form of physical activity than working and leisure activities in the prevention of gallstone disease.

Pregnancy after adjustable gastric banding.

OBJECTIVE: To determine outcomes of pregnancies of obese women who had surgical placement of an adjustable gastric band to treat obesity. METHODS: We conducted two clinical trials to evaluate adjustable gastric banding that involved 359 obese women of reproductive potential (age 18-51 years), of whom 20 conceived resulting in 23 pregnancies. Specific information about pregnancies and fetal outcomes was collected from medical records and direct patient contact. RESULTS: Eighteen pregnancies were full term, one was an ectopic gestation, two ended in elective abortions, and two in spontaneous abortions unrelated to the womens' medical conditions. Of the 18 full-term pregnancies, 14 delivered vaginally and four by cesarean (one for prolonged fetal bradycardia, two for cephalopelvic disproportion, and one repeat cesarean for twins). The mean birth weight was 3676 g (range 2381-3912 g). Five women lost weight (range 1.8-17.6 kg) during pregnancy without obvious fetal and neonatal effects. Three women had fluid removed from their gastric bands (decreasing the mechanical constriction) to treat nausea and vomiting. Two women who had no fluid in their bands eliminated the effectiveness of the obesity treatment, resulting in excessive weight gain. CONCLUSION: Morbidly obese women who became pregnant soon after receiving an adjustable gastric band had uncomplicated pregnancies. Adjustment of the gastric band to decrease the amount of mechanical obstruction decreased nausea and vomiting, but led to excessive weight gain in two women when it was done prophylactically. Obese women at risk of pregnancy should be counseled that it might occur unexpectedly after weight loss from gastric banding unless birth control is promptly instituted.

Socioeconomic issues affecting the treatment of obesity in the new millennium.

The prevalence of obesity among the populations of most developed countries has increased to such an extent that the healthcare and social security/disability system will accumulate direct and indirect costs related to obesity that will be more substantial than those for any other primary disease within this generation. For the past decade, the Healthcare Financing Agency, which oversees the Medicare and Medicaid programmes, has required all physicians and healthcare agencies serving beneficiaries of these programmes to include diagnoses using codes established by the ninth revision of the World Health Organization's International Classification of Diseases. This coding system actually distorts data collection and undermines appropriate medical insurance reimbursement for the treatment of obesity. Societal prejudices, inability of governmental agencies to address future concerns and the business community's attempts to control healthcare costs without addressing the underlying issues contributing to these costs have led to confusion on how to confront this emerging epidemic. How will we develop the scientific knowledge and the political willpower to confront this epidemic? First, we need more accurate methods for classifying obesity and for measuring the cost of treatment. We can then determine if it is more cost effective to prevent or treat obesity early in its evolution or pay for its consequences in the form of treatment costs associated with its multiple comorbid diseases, such as hypertension, other cardiovascular disorders, diabetes mellitus, osteoarthritis and cancers, plus the lost productivity from absenteeism, premature retirement and death.

The medical malpractice risk associated with bariatric surgery.

BACKGROUND: Bariatric surgery has been classified as high risk by the medical malpractice industry, but it is unclear what data support this classification. When a small group of physicians is separated from their peers and asked to support their malpractice claims, their premiums will often rise unfairly in relation to the outcome of the claims. This report outlines the results of a survey sent to the members of the American Society for Bariatric Surgery (ASBS) asking for information on malpractice claims. METHODS: Surveys were mailed to the 285 ASBS members requesting which bariatric operations were performed, how many procedures were completed each year, details of any suits filed against the member including final outcome, and information on whether the members also performed gastric surgery for ulcer disease. RESULTS: Surveys were returned by 165 members (58%) from surgeons in 33 states and Washington, D.C. Malpractice claims had been made after 107 bariatric procedures and three ulcer procedures with the risk of a suit being filed for a bariatric procedure being approximately 1.6/1,000 cases. The average monetary award was $88,667. Of the suits that resulted in a jury trial, 14% agreed with the plaintiff. Over half the cases that had been resolved were either dropped or dismissed before trial. CONCLUSIONS: The incidence of suit being brought against ASBS members performing bariatric procedures is low. Once filed, most cases do not reach a jury trial. Settlements are usually under $100,000. These data suggest that this group of bariatric surgeons do not represent a disproportionately large risk pool for medical malpractice insurance companies.

The biopsychosocial characteristics of people seeking treatment for obesity.

BACKGROUND: To determine prospectively the characteristics of obese patients allowed to select either a medically supervised weight-reduction treatment program or a surgical treatment program, both offered at the same location. METHODS: This was a cohort study at a university medical center where patients, who self-referred themselves for weight loss treatments, were introduced to two different programs before they were allowed to start either program. Four hundred forty-three patients with a mean body mass index (BMI) of 45.6 +/- 0.5 (85 men, 358 women) self-selected either a combined supplemented fast with behavior modification (DIET, n = 208) or gastric bypass surgery (SURG, n = 235). Three hundred forty of these patients had private insurance (PI,) and 103 were receiving Medicaid/Medicare (publicly funded, PF). Each patient completed a semistructured psychiatric interview, obesity questionnaire, Profile of Mood Status (POMS), Beck Depression Inventory (BDI), Minnesota Multiphasic Personality Inventory (MMPI), and Hollingshead Index. RESULTS: Three distinct groups of patients emerged on the basis of their insurance reimbursement patterns (employed versus disabled or indigent) and biopsychosocial factors. The disabled and/or indigent group receiving PF usually chose SURG (n = 89) because their insurance program covered it, but 14 disabled patients receiving Medicare chose DIET (together labeled the PF:DS group). The PI patients were divided into two groups: SURG (PI:S), n = 146, and DIET (PI: D), n = 194, respectively, based on their program selection. These three groups differed significantly in their biopsychosocial patterns. The PF:DS subjects appeared to have the strongest degree of biologic influence, followed by the PI:S and PI:D subjects. The pattern of social influences was consistent with the pattern of biologic influences and the selection bias created in forming the PF and PI groups. The pattern of psychologic influences, however, did not appear to follow the pattern of biologic and social influences. PF:DS had the strongest psychologic loading, but PI:D had a stronger degree of psychopathologic impairment than PI:S. CONCLUSIONS: The significant differences in the biopsychosocial characteristics of these three groups of obese patients need to be considered by policy-makers when they design and review treatment studies and decide what treatment programs should be offered in medical insurance programs.

Cost-benefit analysis for the treatment of severe obesity.

Cost-benefit and cost-effectiveness analyses (CEAs) are only now beginning to be used by business, government, and policymakers to evaluate various medical treatments. The evolution of why CEAs are being demanded is reviewed. To date, a formal CEA of obesity treatments has not been published. This article outlines how a CEA is performed, reviews data relevant to setting up a formal CEA of medical and surgical obesity treatments, and lists published reports that demonstrate the effectiveness of surgical obesity treatments. The general level of discrimination that society allows the obese to suffer also allows medical insurance companies, businesses, and government to not provide many obese Americans with obesity treatments that have established a level of effectiveness far surpassing many other forms of medical therapy. CEAs of obesity treatments, by themselves, cannot be expected to reverse this discrimination. This type of data, however, provides individual obese patients and their physicians with evidence to challenge policymakers' decisions, especially when cost-effective obesity treatments are excluded or placed at a lower priority than treatments with less proven effectiveness.

Obesity without sleep apnea is associated with daytime sleepiness.

BACKGROUND: Daytime sleepiness and fatigue is a frequent complaint of obese patients even among those who do not demonstrate sleep apnea. OBJECTIVE: To assess in the sleep laboratory whether obese patients without sleep apnea are sleepier during the day compared with healthy controls with normal weight. METHODS: Our sample consisted of 73 obese patients without sleep apnea, upper airway resistance syndrome, or hypoventilation syndrome who were consecutively referred for treatment of their obesity and 45 controls matched for age. All patients and healthy controls were monitored in the sleep laboratory for 8 hours at night and at 2 daytime naps, each for 1 hour the following day. RESULTS: Obese patients compared with controls were sleepier during the day and their nighttime sleep was disturbed. During both naps, sleep latency, wake time after onset of sleep, and total wake time were significantly lower, whereas the percentage of sleep time was significantly higher in obese patients compared with controls. In contrast, during the nighttime testing, obese patients compared with controls demonstrated significantly higher wake time after onset of sleep, total wake time, and lower percentage of sleep time. An analysis of the relation between nighttime and daytime sleep suggested that daytime sleepiness in obese patients is a result of a circadian abnormality rather than just being secondary to nighttime sleep disturbance. CONCLUSIONS: Daytime sleepiness is a morbid characteristic of obese patients with a potentially significant impact on their lives and public safety. Daytime sleepiness in individuals with obesity appears to be related to a metabolic and/or circadian abnormality of the disorder.

What surgeons need to know to help patients receive quality medical care in managed care settings.

BACKGROUND: Americans spend more than $3,300 per person per year on health care, an amount businesses, government, and citizens alike consider too high. MATERIAL REVIEWED: Managed care attempts to offer services at a lower cost, about 10% below that of indemnity insurance, and attempts to controls costs by modifying decisions historically made by physician and patient. Many techniques have been used to modify the decision-making process, with varying effects on quality. CONCLUSIONS: Surgeons can help sustain easily accessible, high-quality care through various personal behaviors and through choosing their managed care partners well.

The surgeon's role in improving medical care.

Surgeons have a history of almost 100 years of being in the forefront of efforts to standardize medical care and improve patients' health outcomes. Recently, increases in the "for-profit" sector have made it more difficult for patients to receive quality medical care. In this new era, surgeons need to stay involved in all areas of the establishment of patient care standards, to ensure patients continue to have access to surgical treatments.

Roles of mental health professionals in multidisciplinary medically supervised treatment programs for obesity.

Excess weight is a major medical problem for more than one third of Americans and, after cigarette smoking, is the second largest cause of death. However, obesity treatments remain controversial, and only surgical therapies have patient volume and appropriate follow-up adequate to prove effectiveness. National Institutes of Health conferences on obesity treatments and the Institute of Medicine have suggested that all obesity treatment programs, including those which are medically supervised, should be multidisciplinary, involving professionals from the behavioral, nutritional, and exercise fields to facilitate delivery of a patient-treatment matching strategy. There are no models to suggest how these recommendations should be accomplished or whether they are financially feasible. We present a case management model that includes psychotherapists in a multidisciplinary obesity treatment program. More data are needed to show whether these suggestions improve cost-effectiveness of obesity treatments.

High incidence of IDDM over 6 years in Edmonton, Alberta, Canada.

OBJECTIVE: To determine the incidence of IDDM among children 0-14 years of age in Edmonton, Alberta, between 1990 and 1995 by means of a population-based registry. RESEARCH DESIGN AND METHODS: Children < 15 years of age diagnosed with IDDM between January 1990 and December 1995 were registered according to criteria of the World Health Organization (WHO) Multinational Project for Childhood Diabetes. The primary source of case ascertainment consisted of office records of pediatricians and endocrinologists. The secondary source consisted of inpatient records from the main city hospitals. RESULTS: Between 1990 and 1995, 211 IDDM patients < 15 years of age were detected by the two sources. All but 15 of them were of European ancestry. The ascertainment-corrected incidence rates of this ethnic group (constituting 77% of the population) for the 6 years were 38.6, 23.5, 23.3, 24.2, 22.0, and 24.3 per 100,000, respectively, with case ascertainment rates of 75-95%. The age-adjusted rate over the 6-year period was 25.7 per 100,000 with a case ascertainment rate of 84.3%. No sex difference was observed. The highest incidence occurred in the 10- to 14-year-old age-group, and more cases were detected between January and March than at other periods in the year. CONCLUSIONS: The incidence of IDDM among the European-derived population in Edmonton between 1990 and 1995 is the highest rate over a 6-year period to be reported in North America, comparable to that in Prince Edward Island, Canada, and to the highest rates in the world.

Are learning objectives useful in evaluating medical school course and instructor performance?

We tested the hypothesis that learning objectives could be used to evaluate course and instructor effectiveness. Ninety-seven third-year medical students who had their surgical clerkship or their medical clerkship as their first clinical rotation were compared. The surgery clerks received 171 urologic learning objectives. Students taking the surgical clerkship had significantly higher postclerkship recognition of the learning objectives than did medical clerkship students. One year later, these students were again surveyed to determine whether they still knew the correct response to the learning objective. The follow-up survey showed that 50% of the students recognized objectives covered in five of the eight urology lectures, while the other lectures were not effective. Students who recognized the objective on the postclerkship evaluation were more likely to think the objective had been taught on this follow-up survey. These data suggest that learning objectives are useful for evaluating course and instructor effectiveness.

Comparison of the costs associated with medical and surgical treatment of obesity.

BACKGROUND: We compared the long-term costs and outcomes of gastric bypass versus medical therapy (very low-calorie diet plus weekly behavioral modification) for obese patients. METHODS: A successful outcome was defined as the loss of at least one third of excess weight that was maintained for the duration of the study. A minimal cost was assigned: $3000 for medical and $24,000 for surgical treatment. A cost per pound of weight lost for all patients successfully monitored was calculated. The Federal Trade Commission recently asked all weight loss programs to report this cost for patients at least 2 years after therapy. RESULTS: A total of 201 patients entered surgical and 161 entered medical therapy. The surgical group was initially heavier (mean body mass index [kg/m2] +/- SE = 49.3 +/- 0.6 versus 41.2 +/- 0.7, p < 0.01), but each group's lowest mean body mass index was similar (31.8 versus 32.1, respectively). A significantly higher percentage of patients in the surgical versus the medical group were still successful at year 5: 89% versus 21%. The cost per pound lost for medical therapy exceeded the cost of surgical therapy in the sixth posttreatment year (both more than $250/pound). CONCLUSIONS: Surgical treatment appears to be more cost-effective at producing and maintaining weight loss. It is imperative that long-term follow-up studies be funded to definitely establish this finding.

Beta-adrenergic responsiveness of adenylate cyclase in human adipocyte plasma membranes in obesity and after massive weight reduction.

The aim of this study was to find out how beta-adrenergic responsiveness of adipocytes is altered in obesity and by weight loss and to investigate what mechanisms lead to potential alterations in responsiveness. Crude plasma membranes were prepared from adipocytes of massively obese and normal-weight individuals, as well as previously obese patients that had lost an average of 38% of their initial weight after bariatric surgery. Stimulation of adenylate cyclase by isoproterenol varied considerably in fat cell plasma membranes from different individuals. Crude fat cell plasma membranes from obese patients were less responsive to isoproterenol than those from normal-weight subjects, whereas those from postgastroplasty patients were hyperresponsive. The response was correlated negatively with cell size and positively with beta-adrenergic receptor density and with the ratio of beta-receptors and stimulatory G-proteins (Gs). There was no correlation with Gs content. However, differences in receptor density between small and large cells or normal-weight, obese, and post-bypass patients could not explain the observed differences in responsiveness to isoproterenol between the different groups.

Severe obesity: expensive to society, frustrating to treat, but important to confront.

Obesity is a major contributor to chronic and costly diseases and disabilities. More than 30% of American adults are obese, and the percentage has been rising for 20 years. A recent estimate placed the direct economic costs of obesity at more than $39.3 billion, or 5.5% of all medical expenditures in the mid-1980s. These numbers underestimate prevalence and cost because the studies designed to monitor our nation's health problems have ignored the most obese segment of the population-individuals weighing more than 350 pounds. The methods used to treat obesity are controversial, some of them lacking appropriate evaluation. Physicians have been reluctant to treat obese people because of the intensity and duration of an effective treatment program. Finally, many treatments fail in the long term and therefore are not considered cost effective. Multiple treatment options are currently available, and this review presents data to aid physicians in selection of the best therapy to help their patients. As cost advantages of comprehensive care of obese patients become more obvious under capitated financing systems, further investigation should focus on mechanisms of choosing more individualized care plans to defined subsegments of the obese population to make care more cost effective.

Cyclic AMP and glycerol concentrations in freeze-clamped human omental and subcutaneous adipose tissues.

OBJECTIVE: To compare intracellular concentrations of cyclic AMP, GTP, ATP, AMP and glycerol in omental and abdominal subcutaneous adipose tissues. DESIGN: Samples of omental and/or abdominal subcutaneous adipose tissues of 14 women undergoing elective surgery were freeze-clamped, deproteinized with perchloric acid and neutralized. All subjects were obese since it was not possible to freeze-clamp lean individuals. MEASUREMENTS: The concentrations of ATP and GTP were determined by ion-paired high performance liquid chromatography and AMP and glycerol enzymatically. Cyclic AMP was determined by radioimmunoassay. Intracellular nucleotide concentrations were calculated from tissue weights, water contents and relative amounts of sodium and potassium. RESULTS: The intracellular concentration of cyclic AMP in omental adipose tissue (31 mumol/l) was twice as high as that in subcutaneous fat while those of ATP, GTP and AMP were similar at the two sites. Glycerol concentrations were higher in subcutaneous (472 mumol/l) than in omental (325 mumol/l) adipose tissue. CONCLUSION: The results suggest higher relative stimulation of lipolysis by cyclic AMP in omental adipose tissue than in the subcutaneous region in situ. However, probably because of differences in blood flow and possibly in the lipolytic machinery, this is not reflected as a higher glycerol concentration.

Can morbidly obese patients safely lose weight preoperatively?

BACKGROUND: Preoperative weight loss is often suggested as a means of reducing operative risk in obese patients requiring laparotomy but there are no large studies documenting that this is feasible or helpful. Although several commercial products are available that provide high levels of protein with low levels of carbohydrates in convenient liquid preparations, recommendations regarding the extent to which weight loss can be pursued preoperatively are not available. PURPOSE: To determine whether it is practical and safe to have obese patients lose weight preoperatively. PATIENTS AND METHODS: We asked 100 severely obese patients requesting gastric bypass surgery to diet before their operations. Seventy patients agreed to diet by consuming a 420 Kcal, 70 g protein liquid diet daily for at least 1 month. RESULTS: Forty-seven patients lost at least 7.5 kg (mean +/- SD 17.1 +/- 0.7). The patients who successfully lost weight preoperatively (dieters group) were significantly heavier than patients (nondieters group) who did not lose weight (251% +/- 45% of ideal body weight [IBW] versus 229% +/- 33% IBW, respectively; P < 0.01), had a significantly higher ratio of men to women, and had psychiatric evaluations and psychological test scores that suggested significantly more psychopathology. Other biosocial and medical characteristics were similar. Postoperatively, the dieters and nondieters had similar rates for morbidity. Dieters and nondieters had no differences in wound-healing complications, and subgroups who had collagen deposition measured experimentally had similar amounts of hydroxy-proline accumulation in their wounds. CONCLUSION: These results suggest that a preoperative diet program appeals more to certain subgroups of severely obese patients than to others. An aggressive preoperative weight loss program that encourages patients to lose an average of 17 kg is safe and can be accomplished practically using available commercial products.