Laryngeal mask airway in patients with tracheal stents who are undergoing non-airway related interventions: report of three cases

The tracheal stent is an alternative nonsurgical management tool for patients with tracheal stenosis caused by disease or iatrogenic trauma. Some patients with tracheal stent may need to be anesthetized to allow invasive techniques or surgery to be performed. In these patients, general anesthesia by endotracheal intubation may dislodge the stent distally or cause lethal complications such as bleeding. We describe three patients with a tracheal stent in place, who were anesthetized using a Laryngeal Mask Airway for surgery, with smooth results.     

Enhancement of rat growth hormone binding by membrane disulfide reduction

The effect of disulfide reduction on the binding of [125I]rat GH (rGH) to rat liver plasma membranes and hepatocytes was studied to determine the role of disulfide bonds in the binding of GH to its receptor. The total amount of [125I] rGH bound to the liver receptors increased severalfold in the presence of dithiothreitol and mercaptoethanol. The nonspecific binding also increased at higher concentrations of the reductant, but the amount specifically bound was still greater in the presence of disulfide reductant. In contrast, the disulfide reductant inhibited [125I] human GH (hGH) binding and enhanced its displacement from hypophysectomized female rat hepatocytes. This was similar to the effect of reductants on [125I]hGH binding to normal female rat hepatocytes. The effect of the disulfide reductants on [125I]rGH binding could be prevented or reversed by the simultaneous or subsequent addition of an oxidizing agent such as NAD or oxidized glutathione. Sulfhydryl-reactive agents such as iodoacetamide prevented additional binding of [125I]rGH when added at 30 min of the incubation. The additional [125I] rGH bound in the presence of disulfide reductant was displaceable by excess unlabeled rGH. Both rGH and hGH exhibited similar degrees of disulfide reduction in the presence of mercaptoethanol. The disulfide reductant produced effects on binding at concentrations that resulted in less than 10% reduction of the GH disulfides. We conclude that: 1) the disulfides and sulfhydryls of the hepatocyte membrane are intimately involved in the binding of GH to hepatic receptors; 2) the locus of the disulfides and sulfhydryls may be in the subunit structure of the membrane receptor, but this will require verification using soluble receptors; and 3) the effect of disulfide reducing agents reveals basic differences in the mechanism of binding of rGH and hGH to somatotropic hormone receptors on the hepatocytes.     

Serial electrophysiologic studies of the effects of oral diltiazem on paroxysmal supraventricular tachycardia

In 16 patients with paroxysmal supraventricular tachycardia, electrophysiologic studies were done before and serially at hourly intervals for eight hours after the third oral dose of 90 mg diltiazem given every eight hours. Diltiazem increased both the longest atrial paced cycle length producing type 1 atrioventricular block and the effective refractory period of the atrioventricular conducting system at all measurements. Before diltiazem, all 16 patients had induction of sustained tachycardia. After diltiazem, sustained tachycardia could not be induced in ten patients at any measurements; in these patients, either echo or nonsustained tachycardia was induced. In the remaining six patients, sustained tachycardia was induced, particularly after six hours. Follow-up observations in 12 patients receiving the same dosage of oral diltiazem for 6 +/- 2 months (mean +/- SD), showed that of the eight patients in whom electrophysiologic testing induced either echo or nonsustained tachycardia, six were asymptomatic and two experienced transient palpitation. Of the other four patients with induction of sustained tachycardia, three had transient palpitation and one had occasional attacks of sustained tachycardia requiring modification of therapy. Thus, oral diltiazem increases atrioventricular nodal refractoriness, with an effect lasting up to eight hours. It is an effective agent for the prophylaxis of paroxysmal supraventricular tachycardia.     

A logistic regression analysis of multiple noninvasive tests for the prediction of the presence and extent of coronary artery disease in men

The incremental diagnostic yield of clinical data, exercise ECG, stress thallium scintigraphy, and cardiac fluoroscopy to predict coronary and multivessel disease was assessed in 171 symptomatic men by means of multiple logistic regression analyses. When clinical variables alone were analyzed, chest pain type and age were predictive of coronary disease, whereas chest pain type, age, a family history of premature coronary disease before age 55 years, and abnormal ST-T wave changes on the rest ECG were predictive of multivessel disease. The percentage of patients correctly classified by cardiac fluoroscopy (presence or absence of coronary artery calcification), exercise ECG, and thallium scintigraphy was 9%, 25%, and 50%, respectively, greater than for clinical variables, when the presence or absence of coronary disease was the outcome, and 13%, 25%, and 29%, respectively, when multivessel disease was studied; 5% of patients were misclassified. When the 37 clinical and noninvasive test variables were analyzed jointly, the most significant variable predictive of coronary disease was an abnormal thallium scan and for multivessel disease, the amount of exercise performed. The data from this study provide a quantitative model and confirm previous reports that optimal diagnostic efficacy is obtained when noninvasive tests are ordered sequentially. In symptomatic men, cardiac fluoroscopy is a relatively ineffective test when compared to exercise ECG and thallium scintigraphy.     

Expression of hepatitis B surface antigen with a recombinant adenovirus.

Early region 1 of the adenovirus type 5 genome was replaced with a DNA sequence containing the gene coding for the hepatitis B surface antigen (HBsAg) flanked by the major late promoter from adenovirus 2 and processing and polyadenylylation signals from simian virus 40. In one type of hybrid virus only the adenovirus 2 major late promoter, including just 33 base pairs of the adenovirus type 2 tripartite leader, preceded the coding region of the HBsAg gene. In another, this region was preceded by both the adenovirus major late promoter and almost the entire tripartite leader. The structure of the substituted sequence in each of the recombinant viral DNAs was identical to that in the plasmids used to construct the viruses. Approximately equivalent amounts of HBsAg-specific mRNA were produced late in infection with each recombinant virus. Although HBsAg production was detected late in infection of the hybrid virus not containing the full tripartite leader sequence, its level was 1/70th of that obtained with the hybrid virus containing this sequence. One likely interpretation is that the presence of the tripartite leader at the 5' end of this mRNA is critical for the synthesis of HBsAg polypeptide in the late stage of infection. HBsAg produced upon infection with the hybrid adenoviruses was glycosylated and secreted into the culture medium as particles that were essentially indistinguishable from the 22-nm particles found in human serum.     

Anatomic renal artery branch microdissection to facilitate zero-ischemia partial nephrectomy

Background

Robot-assisted and laparoscopic partial nephrectomies (PNs) for medial tumors are technically challenging even with the hilum clamped and, until now, were impossible to perform with the hilum unclamped.

Objective

Evaluate whether targeted vascular microdissection (VMD) of renal artery branches allows zero-ischemia PN to be performed even for challenging medial tumors.

Design, setting, and participants

A prospective cohort evaluation of 44 patients with renal masses who underwent robot-assisted or laparoscopic zero-ischemia PN either with anatomic VMD (group 1; n = 22) or without anatomic VMD (group 2; n = 22) performed by a single surgeon from April 2010 to January 2011.

Intervention

Zero-ischemia PN with VMD incorporates four maneuvers: (1) preoperative computed tomographic reconstruction of renal arterial branch anatomy, (2) anatomic dissection of targeted, tumor-specific tertiary or higher-order renal arterial branches, (3) neurosurgical aneurysm microsurgical bulldog clamp(s) for superselective tumor devascularization, and (4) transient, controlled reduction of blood pressure, if necessary.

Measurements

Baseline, perioperative, and postoperative data were collected prospectively.

Results and limitations

Group 1 tumors were larger (4.3 vs 2.6 cm; p = 0.011), were more often hilar (41% vs 9%; p = 0.09), were medial (59% and 23%; p = 0.017), were closer to the hilum (1.46 vs 3.26 cm; p = 0.0002), and had a lower C index score (2.1 vs 3.9; p = 0.004) and higher RENAL nephrometry scores (7.7 vs 6.2; p = 0.013). Despite greater complexity, no group 1 tumor required hilar clamping, and perioperative outcomes were similar to those of group 2: operating room time (4.7 and 4.1 h), median blood loss (200 and 100 ml), surgical margins for cancer (all negative), major complications (0% and 9%), and minor complications (18% and 14%). The median serum creatinine level was similar 2 mo postoperatively (1.2 and 1.3 mg/dl). The study was limited by the relatively small sample size.

Conclusions

Anatomic targeted dissection and superselective control of tumor-specific renal arterial branches facilitate zero-ischemia PN. Even challenging medial and hilar tumors can be excised without hilar clamping. Global surgical renal ischemia has been eliminated for most patients undergoing PN at our institution.     

Impact of a multidisciplinary trauma team on the outcome of acute subdural haematoma

IntroductionTo review the outcome of patients with post-traumatic acute subdural haematoma (ASDH) before and after the establishment of a hospital trauma team at a designated trauma centre.MethodA retrospective analysis was conducted on 82 consecutive patients who underwent surgery for post-traumatic ASDH. The ‘PRE’ and ‘POST’ groups included patients admitted before and after the establishment of a hospital trauma team, respectively.Injury severity was assessed by the admission Glasgow coma score, imaging findings, and the revised trauma score. Clinical outcome measures were the hospital length of stay and the Glasgow outcome score (GOS) upon hospital discharge.ResultsThe overall mortality rate was 53.7%. No significant difference was found between the PRE and POST groups. The mean length of hospital stay was also comparable between the two groups. The functional status of those who survived acute hospital care was significantly better in the POST group. Good outcome (GOS of 4 or 5) was achieved in 66.7% of the survivors in the POST group, compared with 25.0% in the PRE group (p = 0.024).ConclusionPost-traumatic ASDH carried a poor prognosis. The mortality rate and hospital length of stay of patients were not found to be reduced after the establishment of a hospital trauma team. The latter, however, was associated with significantly better functional outcome amongst survivors. Although causality cannot be established due to the multitude of factors which may have affected patient outcome, our findings nonetheless provide further support for the introduction of a multidisciplinary hospital trauma team for the optimal care of trauma patients.     

Scale‐up of MSC under hypoxic conditions for allogeneic transplantation and enhancing bony regeneration in a rabbit calvarial defect model

To realize the therapeutic potential of mesenchymal stem cells (MSCs), we aimed to develop a method for isolating and expanding New Zealand rabbit MSCs in a great scale. Rabbit MSCs expanded under hypoxic and normoxic conditions were compared in terms of replication capacity, differentiation potential, and the capacity for allogeneic transplantation in a calvarial defect model. The cells from all tested rabbits were expanded more rapidly when plated at low‐density under hypoxic conditions compared to under normoxic conditions. Moreover, cells expanded under hypoxic conditions increased in the potential of osteoblastic, adipocytic, and chondrocytic differentiation. More importantly, radiographic analysis and micro‐CT measurement of bone volume revealed the hypoxic cells when transplanted in the calvarial defects of another rabbit increased in the ability to repair bone defect compared to the normoxic cells. Six weeks after allogeneic transplantation of hypoxic MSCs, histological analysis revealed a callus spanned the length of the defect, and several bone tissues spotted in the implant. At 12 weeks, new bone had formed throughout the implant. Using BrdU labeling to track the transplanted cells, the hypoxic cells were more detected in the newly formed bone compared to the normoxic cells. For defects treated with allogeneic MSCs, no adverse host response could be detected at any time‐point. In conclusion, we have developed a robust method for isolation and expansion of rabbit MSCs by combining low‐density with hypoxic culture, which can be applied for the design of clinical trials in allogeneic transplantation of MSCs for bone healing. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1213–1220, 2012