In order to understand how isomerization of the retinal drives unidirectional transmembrane ion transport in bacteriorhodopsin, we determined the atomic structures of the BR state and M ...photointermediate of the E204Q mutant, to 1.7 and 1.8 Å resolution, respectively. Comparison of this M, in which proton release to the extracellular surface is blocked, with the previously determined M in the D96N mutant indicates that the changes in the extracellular region are initiated by changes in the electrostatic interactions of the retinal Schiff base with Asp85 and Asp212, but those on the cytoplasmic side originate from steric conflict of the 13-methyl retinal group with Trp182 and distortion of the π-bulge of helix G. The structural changes suggest that protonation of Asp85 initiates a cascade of atomic displacements in the extracellular region that cause release of a proton to the surface. The progressive relaxation of the strained 13-cis retinal chain with deprotonated Schiff base, in turn, initiates atomic displacements in the cytoplasmic region that cause the intercalation of a hydrogen-bonded water molecule between Thr46 and Asp96. This accounts for the lowering of the pKa of Asp96, which then reprotonates the Schiff base via a newly formed chain of water molecules that is extending toward the Schiff base.
Computer-assisted telesurgical devices have recently been approved in the United States for general surgery. To determine the safety and efficacy of these procedures, we performed a prospective trial ...of computer-enhanced “robotic” fundoplication compared to standard laparoscopic control procedures. Consecutive patients undergoing surgical treatment for gastroesophageal reflux were included. The operating surgeon worked at a console using a three-dimensional image and manipulated hand controls. Operative times, complications, and length of hospital stay were recorded. A standardized questionnaire was administered to evaluate symptoms. Twenty patients were entered into each group. There were no differences in age, preoperative weight, or sex. Operative times were significantly longer in the robot group (97 vs. 141 minutes). There were no complications and most patients went home the first postoperative day. At follow-up, symptoms were similar in both groups; however, there was a significant difference in the number of patients taking antisecretory medication—none in the robotic group but six in the laparoscopic group reported regular use. Computer-assisted laparoscopic antireflux surgery is safe. However, operative times are longer, with little difference in outcomes. At the current level of technology and experience, robotic antireflux surgery appears to offer little advantage over standard laparoscopic approaches. (
J Gastrointest Surg 2002;6:11–16.)
BackgroundCarbon dioxide (CO2) pneumoperitoneum usually is created by a compressed gas source. This exposes the patient to cool dry gas delivered at room temperature (21°C) with 0% relative humidity. ...Various delivery methods are available for humidifying and heating CO2 gas. This study was designed to determine the effects of heating and humidifying gas for the intraabdominal environment.MethodsFor this study, 44 patients undergoing laparoscopic Roux-en-Y gastric bypass were randomly assigned to one of four arms in a prospective, randomized, single-blinded fashion: raw CO2 (group 1), heated CO2 (group 2), humidified CO2 (group 3), and heated and humidified CO2 (group 4). A commercially available CO2 heater–humidifier was used. Core temperatures, intraabdominal humidity, perioperative data, and postoperative outcomes were monitored. Peritoneal biopsies were taken in each group at the beginning and end of the case. Biopsies were subjected staining protocols designed to identify structural damage and macrophage activity. Postoperative narcotic use, pain scale scores, recovery room time, and length of hospital stay were recorded. One-way analysis of variance (ANOVA) and the nonparametric Kruskal–Wallis test were used to compare the groups.ResultsDemographics, volume of CO2 used, intraabdominal humidity, bladder temperatures, lens fogging, and operative times were not significantly different between the groups. Core temperatures were stable, and intraabdominal humidity measurements approached 100% for all the patients over the entire procedure. Total narcotic dosage and pain scale scores were not statistically different. Recovery room times and length of hospital stay were similar in all the groups. Only one biopsy in the heated–humidified group showed an increase in macrophage activity.ConclusionsThe intraabdominal environment in terms of temperature and humidity was similar in all the groups. There was no significant difference in the intraoperative body temperatures or the postoperative variable measured. No histologic changes were identified. Heating or humidifying of CO2 is not justified for patients undergoing laparoscopic bariatric surgery.
Introduction
Natural orifice translumenal endoscopic surgery (NOTES) is a rapidly evolving field that provides endoscopic access to the peritoneum via a natural orifice. One important requirement of ...this technique is the need to minimize the risk of clinically significant peritoneal contamination. We report the bacterial load and contamination of the peritoneal cavity in ten patients who underwent diagnostic transgastric endoscopic peritoneoscopy.
Methods
Patients participating in this trial were scheduled to undergo diagnostic laparoscopy for evaluation of presumed pancreatic cancer. Findings at diagnostic laparoscopy were compared with those of diagnostic transgastric endoscopic peritoneoscopy, using an orally placed gastroscope, blinding the endoscopist to the laparoscopic findings. We performed no gastric decontamination. Diagnostic findings, operative times, and clinical course were recorded. Gastroscope and peritoneal fluid aspirates were obtained prior to and after the gastrotomy. Each sample was sent for bacterial colony counts, culture, and identification of species.
Results
Ten patients, with an average age of 63.7 years, have completed the protocol. All patients underwent diagnostic laparoscopy followed by successful transgastric access and diagnostic peritoneoscopy. The average time for laparoscopy was 7.2 min, compared with 18 min for transgastric instrumentation. Bacterial sampling was obtained in all ten patients. The average number of colony-forming units (CFU) in the gastroscope aspirate was 132.1 CFU/ml, peritoneal aspirates prior to creation of a gastrotomy showed 160.4 CFU/ml, and peritoneal sampling after gastrotomy had an average of 642.1 CFU/ml. There was no contamination of the peritoneal cavity with species isolated from the gastroscope aspirate. No infectious complications or leaks were noted at 30-day follow-up.
Conclusions
There was no clinically significant contamination of the peritoneal cavity from the gastroscope after transgastric endoscopic instrumentation in humans. Transgastric instrumentation does contaminate the abdominal cavity but, the pathogens do not mount a clinically significant response in terms of either the species or the bacterial load.
Background. Federally Qualified Health Centers (FQHCs) serve as regular sources of preventive and primary care for low-income families within their communities and are key parts of the health care ...safety net. Objectives. Compare admissions and emergency room visits for ambulatory care sensitive conditions (ACSCs) among Medicaid beneficiaries relying on FQHCs to other Medicaid beneficiaries. Research Design. Retrospective analysis of 1992 Medicaid claims data for 48,738 Medicaid beneficiaries in 24 service areas across five states. Subjects. Medicaid beneficiaries receiving more than 50% of their preventive and primary care services from FQHCs are compared with Medicaid beneficiaries receiving outpatient care from other providers in the same areas. Exclusions-managed care enrollees, beneficiaries more than age 65, dual eligibles (Medicaid and Medicare), and institutionalized populations. Measures. Admissions and emergency room (ER) visits for a set of chronic and acute conditions, known in the literature as ambulatory care sensitive conditions (ACSCs). Results. Medicaid beneficiaries receiving outpatient care from FQHCs were less likely to be hospitalized (1.5% vs. 1.9%, P <0.007) or seek ER care (14.9% vs. 15.7%, P <0.02) for ACSCs than the comparison group. Controlling for case mix and other demographic variables, the odds ratios were, for hospitalizations, OR, 0.80; 95% CI, 0.67 to 0.95; P <0.01, and for ER visits, OR, 0.87; 95% CI, 0.82 to 0.92; P <0.001. Conclusions. Having a regular source of care such as FQHCs can significantly reduce the likelihood of hospitalizations and ER visits for ACSCs. If the reported differentials in ACSC admissions and ER visits were consistently achieved for all Medicaid beneficiaries, substantial savings might be realized.
Traditionally, patients at low risk and high risk of developing dental disease have been encouraged to attend dental recall appointments at regular intervals of six months between appointments. The ...lack of evidence for the effect that different recall intervals between dental check-ups have on patient outcomes, provider workload and healthcare costs is causing considerable uncertainty for the profession and patients, despite the publication of the NICE Guideline on dental recall. The need for primary research has been highlighted in the Health Technology Assessment Group's systematic review of routine dental check-ups, which found little evidence to support or refute the practice of encouraging 6-monthly dental check-ups in adults. The more recent Cochrane review on recall interval concluded there was insufficient evidence to draw any conclusions regarding the potential beneficial or harmful effects of altering the recall interval between dental check-ups. There is therefore an urgent need to assess the relative effectiveness and cost-benefit of different dental recall intervals in a robust, sufficiently powered randomised control trial (RCT) in primary dental care.
This is a four year multi-centre, parallel-group, randomised controlled trial with blinded outcome assessment based in dental primary care in the UK. Practitioners will recruit 2372 dentate adult patients. Patient participants will be randomised to one of three groups: fixed-period six month recall, risk-based recall, or fixed-period twenty-four month recall. Outcome data will be assessed through clinical examination, patient questionnaires and NHS databases. The primary outcomes measure gingival inflammation/bleeding on probing and oral health-related quality of life.
INTERVAL will provide evidence for the most clinically-effective and cost-beneficial recall interval for maintaining optimum oral health in dentate adults attending general dental practice.
ISRCTN95933794 (Date assigned 20/08/2008).
This study evaluated the ability of laparoscopic ultrasonography to detect, localize, and characterize focal liver masses. Laparoscopic ultrasonography and CT portography of the liver were performed ...in 13 patients with known or suspected malignancy. Laparoscopic ultrasonography directly influenced surgical management in four (31%) cases; three by detection of small focal masses and one by exclusion of masses suspected on CT portography. Laparoscopic ultrasonography provided guidance for biopsy or added important anatomic information in three cases. Laparoscopic ultrasonography was complementary to CT portography but added no additional information in three cases, and it failed to provide any information in two cases. Laparoscopic ultrasonography was falsely negative in one case. In this preliminary series, laparoscopic ultrasonography assisted surgeons in critical decision-making by either providing important new information, clarifying questionable areas, or complementing CT portography.
Background: A new type of computer-enhanced telemanipulator device for "robotic" laparoscopic surgery was recently approved. We prospectively evaluated the initial patients undergoing procedures with ...this new device at our institution. Methods: Patient demographics, operative indications, port placement, operative time, robot time, complications, and hospital stay were recorded. Follow-up evaluation was appropriate for the individual procedure. Results: Initially, 35 cases were managed. There were 22 anti-reflux procedures, 9 Heller myotomies, 1 pyloroplasty, 1 distal pancreatectomy with splenectomy, 1 esophagectomy with intrathoracic anastomosis, and 1 diagnostic laparoscopy. The operative times ranged from 88 to 458 min. The robot use times were between 16 and 185 min. There were no device-related complications. Conclusions: Computer-enhanced robotic telesurgery is a safe and effective treatment method for a variety of diseases of the proximal gastrointestinal tract. Further study is needed to determine the benefits of this approach as compared with current technology.
Background
It remains important to determine the risk of bacterial contamination and infectious complications of the peritoneal cavity as it pertains to transgastric natural orifice translumenal ...endoscopic surgery (NOTES) procedures. The infectious implications of such procedures have been quantified in animal models. This report discusses the infectious risks of transgastric endoscopic peritoneoscopy (TEP) in a human clinical trial.
Methods
Under institutional review board approval, 40 patients scheduled for laparoscopic Roux-en-Y gastric bypass (LRYGB) participated in this study. The TEP procedure was performed without preoperative gastric decontamination and without laparoscopic guidance. Preoperative intravenous antibiotics were given. Saline aspirates were taken from the gastric lumen before endoscopic gastrotomy creation and from the peritoneal cavity after transgastric access. Samples were sent for culture, identification, and bacterial counts. Subgroup analysis was performed on patients taking proton pump inhibitors (PPIs). These data were compared with data for “sterile” peritoneal aspirates from a historical cohort of 50 patients undergoing LRYGB.
Results
The median number of bacteria isolated from the gastric aspirates was 980 colony-forming units (CFU)/ml (
n
= 40). The median number of bacteria isolated from the peritoneal aspirates was 323 CFU/ml. Cross-contamination from the stomach to the peritoneal cavity was documented in eight cases. No abscesses or anastomotic leaks were recorded. One port-site infection occurred. Subgroup analysis of 15 patients receiving PPIs showed elevated bacterial counts in gastric aspirates and the post-TEP peritoneal samples compared with patients not receiving PPIs (
n
= 25). This subgroup on PPI’s did not have an increase in infectious complications.
Conclusions
Contamination of the peritoneal cavity does occur with TEP, but this does not lead to an increased risk of infectious complications. Similarly, patients receiving PPIs have an increased gastric bacterial load and increased contamination after TEP but not an increased risk of infectious complications.
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