Mary Wesley

Borrelia burgdorferi intercepts host hormonal signals to regulate expression of outer surface protein A

The Borrelia burgdorferi infectious cycle requires that the organism adapt to vast differences in environmental conditions found in its tick and mammalian hosts. Previous studies have shown that B. burgdorferi accomplishes this accomodation in part by regulating expression of its surface proteins. Outer surface protein A (OspA) is a borrelial protein important in colonization of the tick midgut. OspA is up-regulated when the organism is in its tick host and down-regulated when it is in a mammalian host. However, little is known about how it is up-regulated again in a mammalian host in preparation for entry into a feeding tick. Here, we report that the host neuroendocrine stress hormones, epinephrine and norepinephrine, are specifically bound by B. burgdorferi and result in increased expression of OspA. This recognition is specific and blocked by competitive inhibitors of human adrenergic receptors. To determine whether recognition of catecholamines, which are likely to be present at the site of a tick bite, may play a role in preparing the organism for reentry into a tick from a mammalian host, we administered a β-adrenergic blocker, propranolol, to infected mice. Propranolol significantly reduced uptake of B. burgdorferi by feeding ticks and decreased expression of OspA in B. burgdorferi recovered from ticks that fed on propranolol-treated mice. Our studies suggest that B. burgdorferi may co-opt host neuroendocrine signals to inform the organism of local changes that predict the presence of its next host and allow it to prepare for transition to a new environment.

Pharmacologic prophylaxis against venous thromboembolic complications is not mandatory for all laparoscopic Roux-en-Y gastric bypass procedures.

BACKGROUND Venous thromboembolism (VTE) is a leading cause of postoperative mortality in bariatric surgical patients. The aim of this study is to report the rate of VTE and bleeding complications using no prophylactic pharmacologic anticoagulation among patients undergoing laparoscopic Roux-en-Y gastric bypass. STUDY DESIGN Nine hundred fifty-seven consecutive patients who were older than 18 years, had no history of VTE, and had laparoscopic Roux-en-Y gastric bypass by a single surgeon (RHC) between January 2000 and October 2008 were included. Outcomes, including deep vein thrombosis and pulmonary embolism, were prospectively collected and retrospectively analyzed using SAS (version 9.1, SAS Institute Inc). VTE prophylactic regimen consisted of calf-length pneumatic compression devices placed before anesthesia induction and mandatory ambulation beginning on the day of operation. No prophylactic pharmacologic anticoagulation was used. All data presented as mean +/- SEM. RESULTS Of the 957 patients, 792 were women and 165 were men. Mean age was 41.0 +/- 0.3 years, body mass index (calculated as kg/m(2)) was 49.1 +/- 0.2, and American Society of Anesthesiology scores 2 (29.8%), 3 (69.8%), and 4 (0.4%). Mean operative time was 106.0 +/- 0.8 minutes. Clinically evident deep vein thrombosis developed in three patients (0.31%) and one patient had a pulmonary embolism (0.10%). The one mortality in the cohort was unrelated to VTE. There were seven (0.73%) bleeding complications, of which one resolved without treatment, two required reoperation, and four required blood transfusions. CONCLUSIONS Adequate VTE prophylaxis is achieved using calf-length pneumatic compression devices, early ambulation, and relatively short operative times. Pharmacologic anticoagulation is not mandatory when these conditions are met in patients who have no earlier history of VTE. There are few bleeding complications requiring reoperation or blood transfusions without the use of anticoagulants.

Gastrointestinal symptom improvement after Roux-en-Y gastric bypass: long-term analysis

BACKGROUND Obese patients have a multitude of gastrointestinal symptoms that differ from their nonobese counterparts. The published data remain scant on changes in gastrointestinal symptoms among this cohort before and after Roux-en-Y gastric bypass (RYGB). The aim of this study was to quantify these symptoms and understand the changes that occur after bariatric surgery. METHODS A total of 1724 gastrointestinal symptom surveys were prospectively administered to 763 consecutive patients who underwent laparoscopic RYGB. The patients rated each symptom on a 0-100-mm Liekert scale: 0, absence of symptoms; 33, occasional occurrence; 67, frequent occurrence; 100, continuous. The surveys were administered preoperatively and yearly thereafter. The data are presented as the mean + or - standard error of the mean. RESULTS Of the 763 patients, 137 were black, 610 were white, and 16 were Hispanic; 83% were women and 17% were men. Their age was 40.8 + or - 0.34 years. The body mass index was 48.4 + or - 0.27 kg/m(2). The American Society of Anesthesiologists class was 2 for 31%, 3 for 68%, and 4 for 1%. Of the 763 patients, 63% underwent short-limb RYGB and 37% underwent long-limb RYGB. The preoperative symptom rating was as follows: abdominal pain, 24.3 + or - 0.7; heartburn, 41.0 + or - 0.8; acid regurgitation, 30.9 + or - 0.9; gnawing epigastric sensation, 26.5 + or - 0.9; nausea/vomiting, 18.8 + or - 0.7; borborygmus, 26.2 + or - 0.8; abdominal distension, 30.3 + or - 0.9; eructation, 28.0 + or - 0.8; increased flatus, 38.9 + or - 0.8; decreased passage of stool, 14.8 + or - 0.8; increased passage of stool, 16.4 + or - 0.7; loose stools, 22.1 + or - 0.8; hard stools, 20.5 + or - 0.9; urgent need for defecation, 23.2 + or - 0.8; incomplete evacuation, 22.2 + or - 0.8; difficulty falling asleep, 42.0 + or - 1.1; insomnia, 38.4 + or - 1; feeling rested, 60.1 + or - 1; and difficulty swallowing, 13.5 + or - 0.67. At 1, 2, 3, 4, and 5 years after RYGB, 99.5% 84.2%, 68.4%, 57.9% and 47.4% of these symptoms had improved significantly (P < .05). CONCLUSION Laparoscopic RYGB significantly improves the gastrointestinal symptoms experienced by morbidly obese patients without adversely affecting any of the measured parameters. This improvement in symptoms proved durable in the long term.