Identification and characterization of a histamine-binding lipocalin-like molecule from the relapsing fever tick Ornithodoros turicata.

Lipocalins are low molecular weight membrane transporters that are abundantly expressed in the salivary glands and other tissues of ticks. In this study, we identified a lipocalin-like molecule, designated as otlip, from the soft ticks Ornithodoros turicata, the vector for the relapsing fever causing spirochete Borrelia turicatae. We noted that the expression of otlip was developmentally regulated, with adult ticks expressing significantly higher levels in comparison to the larvae or nymphal ticks. Expression of otlip was evident in both fed and unfed O. turicata ticks, with significantly increased expression in the salivary glands in comparison to the midgut or ovary tissues. High conservation of the biogenic amine-binding motif was evident in the deduced primary amino acid sequence of Otlip. Protein modelling of Otlip revealed conservation of most of the residues involved in binding histamine or serotonin ligand. In vitro assays demonstrated binding of recombinant Otlip with histamine. Furthermore, prediction of post-translational modifications revealed that Otlip contained phosphorylation and myristoylation sites. Taken together, our study not only provides evidence for the presence of a lipocalin-like molecule in O. turicata ticks but also suggests a role for this molecule in the salivary glands of this medically important vector.

Efficacy and safety of heat exchanger added to venovenous bypass circuit during orthotopic liver transplantation.

Hypothermia during orthotopic liver transplantation (OLT) is common despite measures to prevent this complication. We retrospectively analyzed two groups of patients; those managed with (n = 113) or without (n = 109) a heat exchanger (HE) incorporated in the venovenous bypass (VVB) circuit to test the hypothesis that normothermia before liver reperfusion minimizes hypotension during reperfusion and decreases neohepatic transfusion requirements. Use of the HE resulted in significantly warmer patients during reperfusion and at the end of surgery (P < .001). An increase in neohepatic transfusion requirement was observed in patients with HE use: packed red blood cells, 4 +/- 4 versus 3 +/- 3 units; fresh-frozen plasma, 5 +/- 5 versus 4 +/- 4 units; platelets, 8 +/- 8 versus 6 +/- 7 units; and cryoprecipitate, 5 +/- 7 versus 3 +/- 5 units. There was no difference between the two groups in the untoward hemodynamic events during reperfusion of the liver (P = .31). We conclude that during OLT, the use of an HE in a nonheparinized VVB circuit helps maintain normothermia. Our limited experience suggests that its use is safe but does not improve hemodynamic stability during reperfusion or decrease blood loss during the neohepatic period.

Arteriovenous obstruction of arm due to venovenous bypass during liver transplantation.

Two cases of arteriovenous obstruction of the right arm due to venovenous bypass during orthotopic liver transplantation are reported. Possible explanation and risk factors for the development of this complication are discussed.

Early tracheal extubation after liver transplantation.

OBJECTIVE: To assess the value and safety of tracheal extubation in the operating room at the end of liver transplantation. DESIGN: Retrospective chart review. SETTING: University Medical Center. PARTICIPANTS: Eighteen adult patients extubated in the operating room at the end of liver transplantation (study patients) compared with 17 patients who were not extubated and had < or = 3 U of blood transfused during liver transplantation (control patients). INTERVENTIONS: Data collected include severity of preoperative liver disease, anesthetic technique, use of venovenous bypass, surgical time, intraoperative blood replacement, core temperature and arterial blood gases on admission to the intensive care unit (ICU), times to discharge from ICU and the hospital. MEASUREMENTS AND MAIN RESULTS: Except for age (43.9 +/- 2.7 in study patients v 52.4 +/- 2.5 years; p = 0.03), patients were similar with regard to preoperative Child's-Pugh class and liver function tests. Study patients received more crystalloid in the OR (5,306 +/- 561 v 3,771 +/- 454 mL; p = 0.04), were warmer (36.6 degrees C +/- 0.2 degree C v 35.6 degrees C +/- 0.3 degree C; p = 0.01), had a lower arterial pH (7.29 +/- 0.01 v 7.36 +/- 0.02; p = 0.003) and higher arterial carbon dioxide tension (45 +/- 1 v 35 +/- 2 mmHg; p < 0.001) on admission to ICU than controls. There were no significant differences between groups with regard to discharge times from the ICU (50.6 +/- 2.7 hours in the study group v 61.2 +/- 4.7 in control group; p = 0.06), or discharge from the hospital (14.8 +/- 1.6 in the study group v 21.3 +/- 3 days in control group; p = 0.06). CONCLUSIONS: Tracheal extubation of selected patients at the end of liver transplant surgery in the operating room is safe but did not result in decreased ICU or hospital stay.

Liver transplantation in the morbidly obese.

STUDY OBJECTIVE: To test the hypothesis that morbid obesity implies increased difficulty of liver transplantation and increased risk of adverse outcome. DESIGN: Retrospective review of medical records of 40 morbidly obese patients using a control cohort of patients transplanted just before and after the obese patients. SETTING: University medical center. PATIENTS: All morbidly obese patients who underwent liver transplantation over a 52-month period were included. Forty adult patients met criterion for morbid obesity with body mass index greater than 30 kg/m2. Records for 61 time-matched controls were reviewed. MEASUREMENTS AND MAIN RESULTS: Demographic, intraoperative, and postoperative data were collected including preoperative diagnoses, laboratory and pulmonary function tests, intraoperative transfusion requirements and length of surgery postoperative complications, and survival. Data were analyzed using Student's t-tests, and Chi-square analyses as appropriate, with significance considered a p-value less than 0.05. Obese patients were more hypoxemic than controls prior to surgery (PaO2, 82.9 +/- 3.5 vs. 93.0 +/- 3.0 mmHg), were more likely to be diabetic, and had higher creatinine levels (3.0 +/- 0.6 vs. 1.7 +/- 0.2 mg/dl). Despite this evidence of multi organ dysfunction, intraoperative and postoperative pulmonary and cardiac complications did not differ between groups. Though more obese patients had prior cholecystectomy, length of surgery and intraoperative transfusion requirements were not different between groups. Obese patients did not have an increased incidence of reoperation for wound problems, and lengths of intensive care unit and hospital stays did not differ between groups. Graft and patient survival were similar in obese and nonobese liver transplant recipients. CONCLUSION: Morbid obesity alone does not predispose to increased complications or decreased survival after liver transplantation.

Minimum alveolar concentration of isoflurane for tracheal extubation in deeply anesthetized children.

BACKGROUND: The end-tidal anesthetic gas concentration required to prevent the anesthetized patient from coughing or moving during or immediately after tracheal extubation is not known. METHODS: We studied 19 nonpremedicated children between 4 and 9 yr of age (5.5 +/- 1.8, mean +/- standard deviation), ASA physical status 1 or 2, undergoing muscle surgery for correction of strabismus. General anesthesia was induced by a mask using halothane, nitrous oxide, and oxygen, and the trachea was intubated. Anesthesia was maintained with either isoflurane, nitrous oxide, and oxygen (12 patients), or isoflurane, air, and oxygen (7 patients). However, nitrous oxide was discontinued before the end of surgery. At the end of surgery, a predetermined end-tidal isoflurane concentration was achieved, a steady state maintained for at least 10 min, and the trachea was extubated. In patients who coughed or bucked on the endotracheal tube during suctioning of the stomach or pharynx, or who moved or coughed within 1 min of tracheal extubation, or who developed breath-holding or laryngospasm after tracheal extubation, extubation was considered as unsatisfactory. Results were plotted as satisfactory or unsatisfactory extubation versus end-tidal isoflurane concentration. End-tidal concentration of isoflurane at which tracheal extubation was accomplished in 50% of patients satisfactorily was estimated by probit analysis. RESULTS: The minimum alveolar concentration of isoflurane at which 50% of patients had satisfactory tracheal extubation was found to be 1.27% (standard error +/- 0.04%). CONCLUSIONS: In 50% of anesthetized children age 4-9 yr tracheal extubation may be accomplished without coughing or moving at 1.27% end-tidal isoflurane concentration.