Faculty Bibliography

BACKGROUND: : Surgery induces a variety of metabolic, endocrine, and immune changes collectively known as the "stress response," which may often lead to prolonged postoperative convalescence. Anesthetic management may modulate this physiological response, thus affecting the postoperative course. We hypothesized that the intraoperative administration of dexmedetomidine (DEX), a sympatholytic agent, would reduce the stress response and improve the quality of recovery in patients undergoing major surgery. METHODS: : We conducted a prospective randomized double-blinded study of 54 patients undergoing multilevel spinal fusion. Anesthesia was maintained using either propofol/fentanyl/dexmedetomidine (PFD) or propofol/fentanyl/placebo-saline (PFS). The quality of recovery (a primary endpoint) was assessed using a 40-item quality of recovery questionnaire and a 9-question Fatigue Severity Scores. The tests were carried out preoperatively on postoperative days (POD) 1, 2, 3, and 30. Blood samples were collected at baseline, in the postanesthesia care unit, and at POD 1 and were analyzed for levels of cortisol, C-reactive proteins (CRP), and cytokines interleukin (IL)-1alpha, IL-1beta, IL-1ra, IL-2, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha. Data were analyzed using SPSS software (version 18) using a multivariate and mixed model approach to test for the effect of surgery and drug group. Pairwise comparisons were assessed by means of the t test or rank tests after correcting for multiple comparisons. RESULTS: : The global 40-item quality of recovery questionnaire scores showed a significant effect of time (F4,114=22.63, P<0.001) and drug (F1,51=4.368, P=0.042), with average scores decreasing to lower values on POD 1 (163.63+/-2.47) and POD 2 (170.94+/-2.38) compared with baseline (180.56+/-1.588, mean+/-SE, 2-tailed t tests, P<0.001). By POD 3, scores were significantly lower (-13.74 point difference, P=0.005) in the PFS group (169.3+/-3.87) than in the PFD group (183.04+/-2.76). All patients reported significantly higher levels of fatigue postoperatively, but intergroup difference in Fatigue Severity Scores was detected on POD 3 only, with scores in the PFS group higher than in the PFD group (50.0+/-4.0 vs. 36.3+/-4.9, P=0.035). In both groups, plasma cortisol levels were highest in the postanesthesia care unit, whereas CRP levels were elevated on POD 1. DEX significantly reduced the levels of cortisol, but not those of CRP. Levels of cytokines IL-6, IL-8, and IL-10 were significantly higher immediately after surgery and at POD 1. Plasma levels of other cytokines were not affected by surgery. DEX delayed postoperative rise in IL-10 but not in IL-6 or IL-8. CONCLUSIONS: : DEX infusion during multilevel spinal fusions moderately improved the quality of recovery and possibly reduced fatigue in the early postoperative period. Moreover, it reduced plasma levels of cortisol and IL-10 in comparison with the control group. Our sample size was not sufficient to detect differences either in the incidence of complications or in clinically relevant outcomes.

A meta-analytic study of reports of brain tumors and psychiatric symptoms for the past 50 years was conducted to examine potential associations between tumor location and psychiatric symptoms. Results demonstrated that there is a statistically significant association between anorexia symptoms and hypothalamic tumors. For the rest of the brain regions a statistically significant association could not be definitively determined. However, several of the regions demonstrated an increased likelihood of associated symptoms when compared with other regions. The methodological limitations of this analysis are discussed

The conversion of the petrochemical polymer polyethylene terephthalate (PET) to a biodegradable plastic polyhydroxyal-kanoate (PHA) is described here. PET was pyrolised at 450 degrees C resulting in the production of a solid, liquid, and gaseous fraction. The liquid and gaseous fractions were burnt for energy recovery, whereas the solid fraction terephthalic acid (TA) was used as the feedstock for bacterial production of PHA. Strains previously reported to grow on TA were unable to accumulate PHA. We therefore isolated bacteria from soil exposed to PET granules at a PET bottle processing plant From the 32 strains isolated, three strains capable of accumulation of medium chain length PHA (mclPHA) from TA as a sole source of carbon and energy were selected for further study. These isolates were identified using 16S rDNA techniques as P. putida (GO16), P. putida (GO19), and P. frederiksbergensis (GO23). P. putida GO16 and GO19 accumulate PHA composed predominantly of a 3-hydroxydecanoic acid monomer while P. frederiksbergensis GO23 accumulates 3-hydroxydecanoic acid as the predominant monomer with increased amounts of 3-hydroxydodecanoic acid and 3-hydroxydodecenoic acid compared to the other two strains. PHA was detected in all three strains when nitrogen depleted below detectable levels in the growth medium. Strains GO16 and GO19 accumulate PHA at a maximal rate of approximately 8.4 mg PHA/l/h for 12 h before the rate of PHA accumulation decreased dramatically. Strain GO23 accumulates PHA at a lower maximal rate of 4.4 mg PHA/l/h but there was no slow down in the rate of PHA accumulation over time. Each of the PHA polymers is a thermoplastic with the onset of thermal degradation occurring around 308 degrees C with the complete degradation occurring by 370 degrees C. The molecular weight ranged from 74 to 123 kDa. X-ray diffraction indicated crystallinity of the order of 18-31%. Thermal analysis shows a low glass transition (-53 degrees C) with a broad melting endotherm between 0 and 45 degrees C

BACKGROUND: The perioperative course of patients undergoing intracranial surgery is frequently complicated by hypertensive episodes. Dexmedetomidine (DEX), an alpha-2 adrenoreceptor agonist, is gaining popularity in neuroanesthesia, because its sympatholytic and antinociceptive properties may improve hemodynamic stability at critical moments of surgery. We designed this study to assess the efficacy of DEX in controlling hypertensive responses in patients undergoing intracranial surgery. METHODS: Patients scheduled for elective craniotomy were randomly assigned to receive either sevoflurane-opioid or sevoflurane-opioid-DEX anesthesia. Bispectral index was used to maintain a similar level of hypnosis in both groups (40-50). Opioids, sevoflurane, and vasoactive medications were titrated in a routine manner, at the discretion of the blinded anesthesiologist managing the case, to maintain systolic blood pressure (SBP) targeted within 90-130 mm Hg and heart rate (HR) between 50 and 90 bpm. Hemodynamic variables were continuously recorded and stored on a computer for analysis. Efficacy of the anesthetic technique in controlling SBP or HR is inversely proportional to the area under the curve (AUC) outside the targeted range. Areas under the curves above and below targeted ranges for SBP-time (AUCsbp mm Hg*min/h) and HR-time (bpm*min/h) were compared. Coefficient of variation was used to assess hemodynamic stability. RESULTS: Seventy-two patients were recruited for the study. Computerized records of 56 patients only were analyzed because of technical problems with data collection in 14 cases. AUCsbp for above the targeted range was significantly lower for patients in the DEX group (P=0.044). The coefficient of variation for SBP or HR did not differ between groups. A significantly smaller proportion of patients in the DEX group required treatment with antihypertensive medications (12 of 28, 42% vs 24 of 28, 86%, P=0.0008). The DEX group required fewer opioids in the intraoperative period, but there were no differences in the use of sevoflurane. In the postanesthesia care unit, patients in the DEX group had fewer hypertensive episodes (1.25+/-1.55 vs 2.50+/-2.00, P=0.0114) and were discharged earlier (91+/-17 vs 130+/-27 min, P<0.0001). There were no differences in the requirement for postoperative opioids or antiemetics. CONCLUSIONS: By using indices, which assess a global hemodynamic stability of the anesthetic, we determined that intraoperative DEX infusion was effective for blunting the increases in SBP perioperatively. The use of DEX did not increase the incidence of hypotension or bradycardia, common side effects of the drug

Here, we report the use of petrochemical aromatic hydrocarbons as a feedstock for the biotechnological conversion into valuable biodegradable plastic polymers--polyhydroxyalkanoates (PHAs). We assessed the ability of the known Pseudomonas putida species that are able to utilize benzene, toluene, ethylbenzene, p-xylene (BTEX) compounds as a sole carbon and energy source for their ability to produce PHA from the single substrates. P. putida F1 is able to accumulate medium-chain-length (mcl) PHA when supplied with toluene, benzene, or ethylbenzene. P. putida mt-2 accumulates mcl-PHA when supplied with toluene or p-xylene. The highest level of PHA accumulated by cultures in shake flask was 26% cell dry weight for P. putida mt-2 supplied with p-xylene. A synthetic mixture of benzene, toluene, ethylbenzene, p-xylene, and styrene (BTEXS) which mimics the aromatic fraction of mixed plastic pyrolysis oil was supplied to a defined mixed culture of P. putida F1, mt-2, and CA-3 in the shake flasks and fermentation experiments. PHA was accumulated to 24% and to 36% of the cell dry weight of the shake flask and fermentation grown cultures respectively. In addition a three-fold higher cell density was achieved with the mixed culture grown in the bioreactor compared to shake flask experiments. A run in the 5-l fermentor resulted in the utilization of 59.6 g (67.5 ml) of the BTEXS mixture and the production of 6 g of mcl-PHA. The monomer composition of PHA accumulated by the mixed culture was the same as that accumulated by single strains supplied with single substrates with 3-hydroxydecanoic acid occurring as the predominant monomer. The purified polymer was partially crystalline with an average molecular weight of 86.9 kDa. It has a thermal degradation temperature of 350 degrees C and a glass transition temperature of -48.5 degrees C

Objective: To compare the extent of exposure and surgical maneuverability provided by facial translocation and transtemporal approaches for access to the infratemporal fossa and anterolateral skull base. Materials and Methods: Surgical procedures were performed on five fresh frozen adult cadavers (ten sides) with no known pathology. Facial transfacial approaches with and without a mandibulotomy and transtemporal approaches were evaluated. Objective measures were (1) the distance from the surgical plane to designated anatomic landmarks and (2) the surgical angle of exposure. Results: Distances from the surgical plane to the anatomic reference points were comparable for most of the access procedures (3 to 6 cm). The extended midfacial translocation and bilateral facial translocation approaches did, however, provide a shorter operative distance (1 to 3 cm) for access to the infratemporal fossa and contralateral structures, respectively. The transtemporal approaches facilitate a better angle of exposure (74 to 84 degrees) to the petrotemporal region, while the transfacial approaches were superior for access to the infratemporal structures. Conclusions: Based on the results, we propose a clinical algorithm for selecting a surgical approach based on the position and extent of an infratemporal or petrotemporal lesion

BACKGROUND: Plexiform neurofibromas are rarely found in the cauda equina. The most recent report of a plexiform neurofibroma of the cauda equina noted only 2 previously described cases. CASE DESCRIPTION: To these we add the current case, as well as 2 additional previously published cases. We report the case of a 44-year-old man with a sudden exacerbation of his long-standing lower-back and bilateral leg pain. An intradural lesion was seen on magnetic resonance imaging and he underwent surgery. Intraoperatively, there were swollen nerve roots and tumor insinuating itself between the roots. A biopsy was performed, and pathology findings were consistent with plexiform neurofibroma. CONCLUSIONS: Plexiform neurofibroma of the cauda equina is a rare tumor, with variable manifestations. These tumors are not amenable to complete resection. Surgical treatment consists of either partial resection or biopsy, possibly with dural grafting for decompression