Cefoxitin Plasma and Subcutaneous Adipose Tissue Concentration in Patients Undergoing Sleeve Gastrectomy

PURPOSE

Antibiotic dosing in obese surgical patients has not been adequately evaluated. The objective of this study was to identify whether currently prescribed doses of cefoxitin achieve adequate and sustained plasma and tissue concentrations in obese patients undergoing sleeve gastrectomy.

METHODS

A prospective evaluation of plasma and tissue cefoxitin concentrations in patients undergoing sleeve gastrectomy was performed. On the day of the surgical procedure, venous blood samples (5 mL) were collected just before cefoxitin administration and then at 5, 30, 60, 120, and 240 minutes after dose administration. In addition, subcutaneous adipose tissue was collected from the surgical site at the time of surgical incision and at closure. Cefoxitin concentrations in the collected samples were quantified by using an HPLC-ultraviolet method. A standard noncompartmental analysis was performed for each individual cefoxitin plasma concentration-time profile. In addition, the ratio of tissue to plasma concentration was calculated for all patients.

FINDINGS

Plasma and tissue pharmacokinetics of cefoxitin were evaluated in 6 patients undergoing sleeve gastrectomy. The mean age and BMI were 48.7 (6.2) years and 42.8 (7.1) kg/m(2), respectively. At the time of surgical closure, subcutaneous adipose tissue concentrations of cefoxitin were subtherapeutic (<8 µg/mL) in all evaluated patients.

IMPLICATIONS

Current dosing strategies for cefoxitin in obese surgical patients may be inadequate, and there is an urgent need to define the appropriate dosage.

Inducible nitric oxide synthase (iNOS) and nitric oxide (NO) are important mediators of reflux-induced cell signalling in esophageal cells

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has been implicated in both DNA damage induction and aberrant cell signalling in various tissue and cell backgrounds. We investigated here the role of iNOS and NO in DNA damage induction and nuclear factor-kappa B (NF-κB) signalling in esophageal cells in vitro. As esophageal adenocarcinoma develops in a background of Barrett's esophagus secondary to reflux disease, it is possible that inflammatory mediators like NO may be important in esophageal cancer development. We show that reflux components like stomach acid and bile acids [deoxycholic acid (DCA)] can induce iNOS gene and protein expression and produce NO generation in esophageal cells, using real-time PCR, western blotting and NO sensitive fluorescent probes, respectively. This up-regulation of iNOS expression was not dependent on NF-κB activity. DCA-induced DNA damage was independent of NF-κB and only partially dependent on iNOS and NO, as measured by the micronucleus assay. These same reflux constituents also activated the oncogenic transcription factor NF-κB, as measured by transcription factor enzyme-linked immunosorbent assay and gene expression studies with NF-κB linked genes (e.g. interleukin-8). Importantly, we show here for the first time that basal levels of NF-κB activity (and possibly acid and DCA-induced NF-κB) are dependent on iNOS/NO and this may lead to a positive feedback loop whereby induced iNOS is upstream of NF-κB, hence prolonging and potentially amplifying this signalling, presumably through NO activation of NF-κB. Furthermore, we confirm increased protein levels of iNOS in esophageal adenocarcinoma and, therefore, in neoplastic development in the esophagus.

Laparoscopic single-site surgery for placement of an adjustable gastric band: initial experience

BACKGROUND

Laparoendoscopic single-site (LESS) surgery for cholecystectomy and appendectomy are described in the literature. The benefits of these procedures compared with traditional laparoscopic approaches have yet to be determined. To date, no series of LESS surgeries for placement of an adjustable gastric band has been published or documented. This study aimed to determine the safety and feasibility of LESS surgery for placement of an adjustable gastric band.

METHODS

From December 2007 to June 2008, LESS surgery to place an adjustable gastric band via a transumbilical incision was performed for 10 patients with institutional review board approval. Essentially, multiple ports were placed through a single incision in the umbilicus to allow for liver retraction, visualization, and working instruments. All critical steps using a standard pars flaccida technique were performed without alteration.

RESULTS

For this study, 10 patients (9 women and 1 man) were carefully selected. These patients ranged in age from 32 to 61 years (mean, 47 years) and had a mean body mass index (BMI) of 42 kg/m2 (range, 35-45 kg/m2). The patients were selected for absence of both hepatomegaly and central obesity. Superobese patients were not considered for inclusion in the study. The mean operative time was 1 h and 10 min (range, 53 min to 1 h and 48 min). All the patients were discharged home within 23 h of admission, and no perioperative complications were noted. In addition, no wound-related complications occurred. Notably, only 2 of the 10 patients required the use of narcotic analgesia after discharge from the recovery room. There were no intra- or postoperative complications.

CONCLUSIONS

In our experience, LESS surgery for adjustable gastric banding shows this technique to be both feasible and safe for selected patients. Although technical limitations exist that will be improved upon, further studies are needed to compare LESS surgery for placement of an adjustable gastric band with traditional laparoscopic techniques.

Effect of prefeeding on foraging patterns of brushtail possums (Trichosurus vulpecula) about prefeed transects

Context. Brushtail possums (Trichosurus vulpecula) are a major pest of native biodiversity and agricultural production in New Zealand. To maximise the effectiveness of control operations, prefeeding (free-feeding) of non-toxic bait before poison is often used, but the mechanisms by which it does so, remain unclear. One possibility is that prefeeding changes foraging patterns and space use in ways that increase the likelihood of possums finding and eating a lethal dose of poison bait. Aim. To determine whether prefeeding along transects increases possum activity on the transect, and if so, how long the effect lasts. Methods. We monitored the time that radio-collared possums spent within a few metres of 350 m of aerial wire laid along a transect. Key results. Initially, possums spent only 2.6 min per night in the vicinity of the wire, but after 20 kg of bait per kilometre were placed along the wire, that time increased 20-fold on the first night and remained high for the next four nights (by which time all of the bait had been consumed). After that there was a gradual decline in time spent near the wire over a further 18 days. The increased amount of time spent near the wire was the product of both an increase in the number of visits and the duration of those visits. Conclusions. We conclude that sowing prefeed in concentrated strips is likely to greatly increase the probability of possums rapidly encountering toxic bait sown along the same strips, especially where the toxin can be sown immediately after all of the prefeed has been eaten. Implications. Possum control operations can now be designed to apply much smaller quantities of toxic bait that will potentially reduce concerns about 1080 poisoning because of a move away from broadcast sowing operations that are intuitively disliked by many, to much more localised baiting regimes.

Measuring post-traumatic amnesia (PTA): an historical review

The duration of post-traumatic amnesia (PTA), which is the period following brain injury when patients are disoriented and impaired in the acquisition of new information, has been used as a behavioural indicator of the severity of injury. This paper reviews earlier retrospective and more recently developed prospective methods of assessing the duration of PTA. Prospective assessment that commences before the resolution of PTA overcomes the possible over- or underestimation of the duration of PTA inherent in methods that assess PTA retrospectively by clinical interview.