An ergonomic evaluation of surgeons' axial skeletal and upper extremity movements during laparoscopic and open surgery

BACKGROUND

Many surgeons have complained of fatigue and musculoskeletal pain after laparoscopic surgery. We evaluated differences in surgeons' axial skeletal and upper extremity movements during laparoscopic and open operations.

METHODS

Five surgeons were videotaped performing 16 operations (8 laparoscopic and 8 open) to record their neck, trunk, shoulder, elbow, and wrist movements during the first hour of surgery. We also compared postprocedural complaints of pain, stiffness, or numbness between the two groups.

RESULTS

Compared with surgeons performing open surgery, surgeons performing laparoscopic surgery exhibited less lateral neck flexion; less trunk flexion; more internal rotation of the shoulders; more elbow flexion; more wrist supination and wrist ulnar and radial deviation. There was a trend of more shoulder stiffness after laparoscopic operations than after open operations.

CONCLUSIONS

Laparoscopic surgery involves a more static posture of the neck and trunk, but more frequent awkward movements of the upper extremities than open surgery. Ergonomic changes in the operating room environment and instrument design could ease the physical stress imposed on surgeons during laparoscopic operations.

Comparative analysis of folding and substrate binding sites between regulated hexameric type II citrate synthases and unregulated dimeric type I enzymes

We describe the first structure determination of a type II citrate synthase, an enzyme uniquely found in Gram-negative bacteria. Such enzymes are hexameric and are strongly and specifically inhibited by NADH through an allosteric mechanism. This is in contrast to the widespread dimeric type I citrate synthases found in other organisms, which do not show allosteric properties. Our structure of the hexameric type II citrate synthase from Escherichia coli is composed of three identical dimer units arranged about a central 3-fold axis. The interactions that lead to hexamer formation are concentrated in a relatively small region composed of helix F, FG and IJ helical turns, and a seven-residue loop between helices J and K. This latter loop is present only in type II citrate synthase sequences. Running through the middle of the hexamer complex, and along the 3-fold axis relating dimer units, is a remarkable pore lined with 18 cationic residues and an associated hydrogen-bonded network. Also unexpected was the observation of a novel N-terminal domain, formed by the collective interactions of the first 52 residues from the two subunits of each dimer. The domain formed is rich in beta-sheet structure and has no counterpart in previous structural studies of type I citrate synthases. This domain is located well away from the dimer-dimer contacts that form the hexamer, and it is not involved in hexamer formation. Another surprising observation from the structure of type II E. coli citrate synthase is the unusual polypeptide chain folding found at the putative acetylcoenzyme A binding site. Key parts of this region, including His264 and a portion of polypeptide chain known from type I structures to form an adenine binding loop (residues 299-303), are shifted by as much as 10 A from where they must be for substrate binding and catalysis to occur. Furthermore, the adjacent polypeptide chain composed of residues 267-297 is extremely mobile in our structure. Thus, acetylcoenzyme A binding to type II E. coli citrate synthase would require substantial structural shifts and a concerted refolding of the polypeptide chain to form an appropriate binding subsite. We propose that this essential rearrangement of the acetylcoenzyme A binding part of the active site is also a major feature of allostery in type II citrate synthases. Overall, this study suggests that the evolutionary development of hexameric association, the elaboration of a novel N-terminal domain, introduction of a NADH binding site, and the need to refold a key substrate binding site are all elements that have been developed to allow for the allosteric control of catalysis in the type II citrate synthases.

Cyclophotocoagulation: a report by the American Academy of Ophthalmology

OBJECTIVE

This document describes cyclophotocoagulation procedures for glaucoma and examines the evidence to answer key questions about patient selection, and efficacy of transscleral and endoscopic techniques.

METHODS

A literature search conducted for the years 1968 to 2000 retrieved 130 citations. The author reviewed 34 of these articles and selected 19 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies.

RESULTS

The predominant problem with all studies on cyclophotocoagulation is the lack of a uniform definition of success, which makes comparisons difficult. One randomized controlled trial (Level I evidence) compared the efficacy of transscleral cyclophotocoagulation with noncontact Nd:YAG and semiconductor diode laser. It found no significant difference between the two, although a significant problem was the variability allowed with laser parameters. Most of the literature consists of noncomparative case series that provide evidence that is limited and often not convincing.

CONCLUSION

Cyclophotocoagulation is indicated for patients with refractory glaucoma who have failed trabeculectomy or tube shunt procedures, patients with minimal useful vision and elevated intraocular pressure, and patients who have no visual potential and need pain relief (based on Level III evidence). It may be useful for patients whose general medical condition precludes invasive surgery or who refuse more aggressive surgery (i.e., filter or tube). It is also useful in emergent situations, such as the acute onset of neovascular glaucoma. There is insufficient evidence to definitively compare the relative efficacy of the cyclophotocoagulation procedures for glaucoma. It is the panel's opinion, however, that semiconductor diode systems appear to possess the best combination of effectiveness (based on Level III evidence), portability, expense, and ease of use at this time.

Evaluation of core temperature during laparoscopic and open gastric bypass

BACKGROUND

Intraoperative hypothermia is a common event during open and laparoscopic abdominal surgery. The aim of this study was to compare changes in core temperature between laparoscopic and open gastric bypass (GBP).

METHODS

101 patients with a body mass index (BMI) of 40-60 kg/m2 were randomly assigned to open (n = 50) or laparoscopic (n = 51) GBP. Anesthetic technique was similar for both groups. An external warming blanket and passive airway humidification were used intraoperatively. Core temperature was recorded at preanesthesia, at baseline (after induction) and at 30-min intervals; intra-abdominal temperature was additionally measured at 30-min intervals in a subset of 30 laparoscopic GBP patients. The number of patients who developed intraoperative and postoperative hypothermia (< 36 degrees C) was recorded. Length of operation for both groups and the amount of CO2 gas delivered during laparoscopic operations were also recorded.

RESULTS

There was no significant difference between groups with respect to age, gender, mean BMI, and amount of intravenous fluid administered. After induction of anesthesia, core temperature significantly decreased in both groups; 36% of patients in the open group and 37% of patients in the laparoscopic group developed hypothermia. This percentage increased to 46% in the open group and 41% in the laparoscopic group during the operation, and then decreased to 6% in the open group and 8% in the laparoscopic group in the recovery-room. Core temperature increased during the operative procedure to reach 36.5 +/- 0.6 degrees C in the open group and 36.3 +/- 0.5 degrees C in the laparoscopic group at 2.5 hours after surgical incision. Intra-abdominal temperature during laparoscopic GBP was significantly lower than core temperature at all measurement points (p < 0.05). Operative time was longer in the laparoscopic group than in the open group (232 +/- 43 vs 201 +/- 38 min, p < 0.01). Mean volume of gas delivered during laparoscopic GBP was 650 +/- 220 liters.

CONCLUSION

Perioperative hypothermia was a common event during both laparoscopic and open GBP. Despite a longer operative time, laparoscopic GBP did not increase the rate of intraoperative hypothermia when efforts were made to minimize intraoperative heat loss.

Laparoscopic versus open gastric bypass: a randomized study of outcomes, quality of life, and costs

OBJECTIVE

To compare outcomes, quality of life (QOL), and costs of laparoscopic and open gastric bypass (GBP).

SUMMARY BACKGROUND DATA

Laparoscopic GBP has been reported to be a safe and effective approach for the treatment of morbid obesity. The authors performed a prospective randomized trial to compare outcomes, QOL, and costs of laparoscopic GBP with those of open GBP.

METHODS

From May 1999 to March 2001, 155 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 79) or open (n = 76) GBP. The two groups were similar in age, sex ratio, mean BMI, and comorbidities. Main outcome measures included operative time, estimated blood loss, length of hospital stay, operative complications, percentage of excess body weight loss, and time to return to activities of daily living and work. Changes in QOL were assessed using the SF-36 Health Survey and the bariatric analysis of reporting outcome system (BAROS). Operative and hospital costs of the two operations were also compared.

RESULTS

There were no deaths in either group. Mean operative time was longer for laparoscopic GBP than for open GBP, but operative blood loss was less. Two (2.5%) of the 79 patients in the laparoscopic group required conversion to laparotomy. Median length of hospital stay was shorter for laparoscopic GBP patients (3 vs 4 days). The rate of postoperative anastomotic leak was similar between groups. Wound-related complications such as infection (10.5 vs 1.3%) and incisional hernia (7.9 vs 0%) were more common after open GBP; late anastomotic stricture was less frequent after open GBP (2.6 vs 11.4%). Time to return to activities of daily living and work were shorter after laparoscopic GBP than after open GBP. Weight loss at 1 year was similar between groups. Preoperative SF-36 scores were similar between groups; however, at 1 month after surgery, laparoscopic patients had better physical conditioning, social functioning, general health, and less body pain than open GBP patients. At 6 months, the BAROS outcome was classified as good or better in 97% of laparoscopic GBP patients compared with 82% of open GBP patients. Operative costs were higher for laparoscopic GBP patients, but hospital costs were lower.

CONCLUSIONS

Laparoscopic GBP is a safe and cost-effective alternative to open GBP. Despite a longer operative time, patients undergoing laparoscopic GBP benefited from less blood loss, a shorter hospital stay, and faster convalescence. Laparoscopic GBP patients had comparable weight loss at 1 year but a more rapid improvement in QOL than open GBP patients. The higher initial operative costs for laparoscopic GBP were adequately offset by the lower hospital costs.

Evaluation of intra-abdominal pressure after laparoscopic and open gastric bypass

BACKGROUND

Increased intra-abdominal pressure (IAP) postoperatively can adversely affect cardiovascular, pulmonary, and renal function. In this prospective, randomized trial, we compared the IAP in morbidly obese patients after laparoscopic and open gastric bypass (GBP) surgery.

METHODS

64 patients with a body mass index of 40 to 60 kg/m2 were randomized to undergo laparoscopic or open GBP. IAPs were obtained at baseline (after induction of anesthesia), immediately after the operation, and on post-operative day (POD) 1, 2, and 3. Intraoperative and postoperative fluid requirements, urine output, and creatinine clearance were recorded.

RESULTS

Demographics of the two groups were similar. IAP increased from baseline immediately after laparoscopic and open GBP (p < 0.05). IAP returned to baseline by POD 2 after laparoscopic GBP but remained elevated through POD 3 after open GBP. In fact, IAP was lower after laparoscopic GBP than after open GBP on POD 1, 2 and 3 (p < 0.05). The amount of intraoperative IV fluid was similar between groups, but laparoscopic GBP required less IV fluid and facilitated higher urine output postoperatively than open GBP. There was no significant difference in creatinine clearance between groups.

CONCLUSIONS

Laparoscopic GBP resulted in significantly lower IAP, less postoperative fluid required, and greater postoperative urine output than open GBP.

Minimally invasive Ivor Lewis esophagectomy

Ivor Lewis esophagectomy consists of a laparotomy and right thoracotomy for resection of the intrathoracic esophagus. Recent advances in minimally invasive surgical technology have allowed surgeons to apply laparoscopy and thoracoscopy to perform esophagectomy. However, there have been few reports that describe a totally minimally invasive Ivor Lewis esophagectomy. We present a case of combined laparoscopic and thoracoscopic resection of the distal third esophagus with an intrathoracic esophagogastric reconstruction for esophageal carcinoma.

Systemic coagulation and fibrinolysis after laparoscopic and open gastric bypass

HYPOTHESIS

Laparoscopic gastric bypass (GBP) induces a postoperative hypercoagulable state that is similar or reduced compared with open GBP.

SETTING

University hospital.

PATIENTS

Between May 1999 and June 2000, 70 patients were randomly assigned to laparoscopic (n = 36) or open (n = 34) GBP. Deep venous thrombosis (DVT) prophylaxis consisted of antiembolism stockings and sequential pneumatic compression devices.

MAIN OUTCOME MEASURES

Plasminogen, thrombin-antithrombin complex (TAT), prothrombin fragment 1.2 (F1.2), fibrinogen, D-dimer, antithrombin III (AT), and protein C levels were measured at baseline and at 1, 24, 48, and 72 hours postoperatively. A venous duplex examination of both lower extremities was performed preoperatively and between the third and fifth day postoperatively.

RESULTS

The 2 groups were similar in age, weight, and body mass index. Plasminogen levels decreased, and TAT, F1.2, and fibrinogen levels increased after laparoscopic and open GBP. There was no significant difference in these levels between groups. D-dimer levels increased in both groups, but the levels were significantly higher after open GBP than after laparoscopic GBP (P<.01). Antithrombin III and protein C levels decreased in both groups. The reduction of AT (at 1 hour) and protein C (at 72 hours) was significantly less after laparoscopic GBP than after open GBP (P<.05). Postoperative venous duplex examination revealed DVT in 1 (2.9%) of 34 patients after open GBP but in none of 36 patients after laparoscopic GBP. One patient developed pulmonary embolism after open GBP.

CONCLUSIONS

Laparoscopic GBP induces a hypercoagulable state similar to that of open GBP. Our findings suggest that DVT prophylaxis should be used during laparoscopic GBP as in open GBP.

BBG2Na an RSV subunit vaccine candidate intramuscularly injected to human confers protection against viral challenge after nasal immunization in mice

Respiratory syncytial virus (RSV) is a major respiratory pathogen responsible for severe pulmonary disease. We have developed a parenterally administered vaccine, BBG2Na, which is currently in a phase III clinical trial. BBG2Na comprises residues 130--230 of RSV-A G protein (G2Na) fused to the BB carrier protein. In this study, we show that BBG2Na can be delivered by the nasal route and generates both mucosal and systemic antibody responses when co-administered with cholera toxin B or a newly described delivery system, zwittergent 3--14. We found that nasal BBG2Na administration protects against RSV challenge and does not induce lung immunopathology upon subsequent RSV challenge.

Results of expandable metal stents for malignant esophageal obstruction in 100 patients: short-term and long-term follow-up

BACKGROUND

Expandable metal stents palliate malignant dysphagia in most cases, but early complications and outcomes in long-term survivors have not been well described. This report summarizes our experience with expandable metal stents for malignant dysphagia.

METHODS

Over a 48-month period, 127 stents were placed in 100 patients with dysphagia from esophageal cancer (93%) or lung cancer. Most had undergone prior treatment. Dysphagia scores, duration of palliation, complications, and reintervention were evaluated.

RESULTS

Immediate improvement in dysphagia was observed in 85% of patients with no procedure-related deaths. Dysphagia score decreased from 3.3 before stent to 2.3 (p < 0.005). Average interval to reintervention was 80 days. In 40 patients surviving more than 120 days, 31 (78%) required reintervention. Major complications occurred in 3 patients receiving poststent chemoradiation (tracheoesophageal fistula, T1 vertebral body abscess, mediastinal abscess). Other complications included unsatisfactory deployment requiring immediate removal (3 patients), migration (11 patients), pain requiring removal (2 patients), food impaction (10 patients), and tumor ingrowth (37 patients).

CONCLUSIONS

Expandable metal stents offer excellent short-term palliation of malignant dysphagia. In long-term survivors, recurrent dysphagia requiring reintervention is common. In a small subset of patients receiving chemoradiation after stent placement, major complications were observed.

Comparison of sestamibi, tetrofosmin, and Q12 retention in porcine myocardium

Although there are several 99mTc perfusion tracers introduced for clinical use, there are no data available directly comparing these tracers with microsphere-determined flow. The aim of this study was to compare the myocardial retention of sestamibi, tetrofosmin, and Q12 in a porcine model.

METHODS

We used a pig model with (n = 6) or without (n = 3) coronary occlusion. Each pig received a simultaneous injection of sestamibi and either tetrofosmin (group 1, n = 5) or Q12 (group 2, n = 4) labeled with either 99mTc or 95mTc (physical half-life, 61 d; photon energy, 204 keV) during pharmacologic vasodilation. Absolute myocardial retention of each tracer was calculated from the myocardial tracer activity and arterial input function.

RESULTS

The plot of all three tracers versus flow achieved a plateau at a higher flow range. However, sestamibi showed a higher mean retention than either tetrofosmin (group 1, 0.27 +/- 0.11 vs. 0.16 +/- 0.06 mL/g/min, respectively; P < 0.01) or Q12 (group 2, 0.32 +/- 0.13 vs. 0.09 +/- 0.03 mL/g/min, respectively; P < 0.01). Furthermore, when a linear regression analysis was performed to assess the relationship between retention and microsphere-determined flow, sestamibi showed a greater increment in retention than did tetrofosmin or Q12.

CONCLUSION

Although all of the tracers showed a nonlinear increase in retention as flow increased, sestamibi may display more favorable characteristics as a flow tracer in the porcine heart.

A Prospective Evaluation of Intracorporeal Laparoscopic Small Bowel Anastomosis during Gastric Bypass

BACKGROUND

We evaluated the safety and feasibility of performing a laparoscopic intracorporeal end-to-side small bowel anastomosis using a stapling technique as part of a Roux-en-Y gastric bypass operation (RYGBP).

METHODS

80 consecutive patients who underwent RYGBP with laparoscopic jejunojejunostomy were evaluated. Operative time and intraoperative and postoperative complications directly related to the jejunojejunostomy anastomosis were recorded.

RESULTS

All 80 laparoscopic jejunojejunostomy procedures were successfully performed without conversion to laparotomy. Mean operative time was longer for the first 40 laparoscopic RYGBP than for the last 40 RYGBP (32+/-18 min vs 21+/-14 min, respectively, p<0.05). Intraoperative complications were staple-line bleeding (2 patients) and narrowing of the anastomosis (1 patient). Postoperative complications were four small bowel obstructions: technical narrowing at jejunojejunostomy site (2 patients), angulation of the afferent limb (1 patient), and food impaction at the jejunojejunostomy anastomosis (1 patient). These four patients underwent successful laparoscopic re-exploration and creation of another jejunojejunostomy proximal to the original anastomosis. There were no small bowel anastomotic leaks. The median time to resuming oral diet was 2 days.

CONCLUSIONS

Laparoscopic jejunojejunostomy as part of the RYGBP operation is a safe and technically feasible procedure. Postoperative small bowel obstruction is a potential complication, which can be prevented by avoiding technical narrowing of the afferent limb.

Comparison of pulmonary function and postoperative pain after laparoscopic versus open gastric bypass: a randomized trial

BACKGROUND

Impairment of pulmonary function is common after upper abdominal operations. The purpose of this study was to compare postoperative pulmonary function and analgesic requirements in patients undergoing either laparoscopic or open Roux-en-Y gastric bypass (GBP).

STUDY DESIGN

Seventy patients with a body mass index of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 36) or open (n = 34) GBP. The two groups were similar in age, gender, body mass index, pulmonary history, and baseline pulmonary function. Pulmonary function studies were performed preoperatively and on postoperative days 1, 2, 3, and 7. Oxygen saturation and chest radiographs were performed on both groups preoperatively and on postoperative day 1. Postoperative pain was evaluated using a visual analog scale and the amount of narcotic consumed was recorded. Data are presented as mean +/- standard deviation.

RESULTS

Laparoscopic GBP patients had significantly less impairment of pulmonary function than open GBP patients on the first three postoperative days (p < 0.05). By the 7th postoperative day, all pulmonary function parameters in the laparoscopic GBP group had returned to within preoperative levels, but only one parameter (peak expiratory flow) had returned to preoperative levels in the open GBP group. On the first postoperative day, laparoscopic GBP patients used less morphine than open GBP patients (46 +/- 31 mg versus 76 +/- 39 mg, respectively, p < 0.001), and visual analog scale pain scores at rest and during mobilization were lower after laparoscopic GBP than after open GBP (p < 0.05). Fewer patients after laparoscopic GBP than after open GBP developed hypoxemia (31% versus 76%, p < 0.001) and segmental atelectasis (6% versus 55%, p = 0.003).

CONCLUSION

Laparoscopic gastric bypass resulted in less postoperative suppression of pulmonary function, decreased pain, improved oxygenation, and less atelectasis than open gastric bypass.

Up-regulation of vascular endothelial growth factor in breast cancer cells by the heregulin-beta1-activated p38 signaling pathway enhances endothelial cell migration

Heregulin (HRG) belongs to a family of polypeptide growth factors that bind to receptor tyrosine kinases ErbB3 and ErbB4. HRG binding induces ErbB3 and ErbB4 heterodimerization with ErbB2, activating downstream signal transduction. Vascular endothelial growth factor (VEGF) is a primary regulator of physiological angiogenesis and is a major mediator of pathological angiogenesis, such as tumor-associated neovascularization. In this study, we demonstrate that HRG-beta1 increased secretion of VEGF from breast cancer cells in a time- and dosage-dependent manner and that this increase resulted from up-regulation of VEGF mRNA expression via transcriptional activation of the VEGF promoter. Deletion and mutational analysis revealed that a CA-rich upstream HRG response element located between nucleotide-2249 and -2242 in the VEGF promoter mediated HRG-induced transcriptional up-regulation of VEGF. While investigating the downstream signaling pathways involved in HRG-mediated up-regulation of VEGF, we found that HRG activated extracellular signal-regulated protein kinases, Akt kinase, and p38 mitogen-activated protein kinase (MAPK). However, only the specific inhibitor of p38 MAPK (SB203580), not extracellular signal-regulated kinase inhibitor PD98059 nor the inhibitor of phosphatidylinositol 3-kinase-Akt pathway (Wortmannin), blocked the up-regulation of VEGF by HRG. The HRG-stimulated secretion of VEGF from breast cancer cells resulted in increased migration of murine lung endothelial cells, an activity that was inhibited by either VEGF-neutralizing antibody or SB203580. These results show that HRG can activate p38 MAPK to enhance VEGF transcription via an upstream HRG response element, leading to increased VEGF secretion and angiogenic response in breast cancer cells.

Minimally invasive esophagectomy

BACKGROUND

Open esophagectomy can be associated with significant morbidity and delay return to routine activities. Minimally invasive surgery may lower the morbidity of esophagectomy but only a few small series have been published.

METHODS

From August 1996 to September 1999, 77 patients underwent minimally invasive esophagectomy. Initially, esophagectomy was approached totally laparoscopically or with mini-thoracotomy; thoracoscopy subsequently replaced thoracotomy.

RESULTS

Indications included esophageal carcinoma (n = 54), Barrett's high-grade dysplasia or carcinoma in situ (n = 17), and benign miscellaneous (n = 6). There were 50 men and 27 women with an average age of 66 years (range 30 to 94 years). Median operative time was 7.5 hours (4.5 hours with > 20 case experience). Median intensive care unit stay was 1 day (range 0 to 60 days); median length of stay was 7 days (range 4 to 73 days) with no operative or hospital mortalities. There were four nonemergent conversions to open esophagectomy; major and minor complication rates were 27% and 55%, respectively.

CONCLUSIONS

Minimally invasive esophagectomy is technically feasible and safe in our center, which has extensive minimally invasive and open esophageal experience. Open surgery should remain the standard until future studies conclusively demonstrate advantages of minimally invasive approaches.

Laparoscopic suturing evaluation among surgical residents

BACKGROUND

Laparoscopic suturing is an integral part of advanced laparoscopic surgery training. The objective of this study was to evaluate the performance and preference of surgical residents performing intracorporeal and extracorporeal knot-tying techniques using conventional and Endo Stitch instruments. The residents were also evaluated on their suturing techniques using conventional instruments, the Endo Stitch, and the Suture Assistant.

METHODS

Using an inanimate laparoscopic trainer model, 39 residents were evaluated as they performed laparoscopic knot tying exercises. Endpoints of the study were execution time and subjective preference of surgical residents with respect to the type of instrument used for knot tying. Forty-three residents were evaluated as they performed laparoscopic suturing exercises with three different types of suturing instruments using the same endpoints.

RESULTS

The intracorporeal technique was the preferred (89%) method of knot tying among surgical residents. The time for completion of laparoscopic suturing was significantly (P < 0.05) shorter with the Endo Stitch (114 +/- 64 s) than with the conventional instrument (206 +/- 107 s) or the Suture Assistant (151 +/- 70 s). Residents preferred the use of the Endo Stitch in all three categories for suturing, knot tying, and handling.

CONCLUSION

The Endo Stitch enhanced laparoscopic skills and was the preferred instrument for laparoscopic knot tying and suturing among surgical residents.

Comparison of minimally invasive esophagectomy with transthoracic and transhiatal esophagectomy

HYPOTHESIS

Minimally invasive esophagectomy can be performed as safely as conventional esophagectomy and has distinct perioperative outcome advantages.

DESIGN

A retrospective comparison of 3 methods of esophagectomy: minimally invasive, transthoracic, and blunt transhiatal.

SETTING

University medical center.

PATIENTS

Eighteen consecutive patients underwent combined thoracoscopic and laparoscopic esophagectomy from October 9, 1998, through January 19, 2000. These patients were compared with 16 patients who underwent transthoracic esophagectomy and 20 patients who underwent blunt transhiatal esophagectomy from June 1, 1993, through August 5, 1998.

MAIN OUTCOME MEASURES

Operative time, amount of blood loss, number of operative transfusions, length of intensive care and hospital stays, complications, and mortality.

RESULTS

Patients who had minimally invasive esophagectomy had shorter operative times, less blood loss, fewer transfusions, and shortened intensive care unit and hospital courses than patients who underwent transthoracic or blunt transhiatal esophagectomy. There was no significant difference in the incidence of anastomotic leak or respiratory complications among the 3 groups.

CONCLUSION

Minimally invasive esophagectomy is safe and provides clinical advantages compared with transthoracic and blunt transhiatal esophagectomy.

Minimally invasive surgical staging for esophageal cancer

BACKGROUND

The incidence of esophageal adenocarcinoma is increasing in the United States, and the 5-year survival rate is dismal. Preliminary data suggest that conventional imaging is inaccurate in staging esophageal cancer and could limit accurate assessment of new treatments. The objective of this study was to compare minimally invasive surgical staging (MIS) with conventional imaging for staging esophageal cancer.

METHODS

Patients with potentially resectable esophageal cancer were eligible. Staging by conventional methods used computed tomography (CT) scan of the chest and abdomen, and endoscopic ultrasound (EUS), whereas MIS used laparoscopy and videothoracoscopy. Conventional staging results were compared to those from MIS.

RESULTS

In 53 patients, the following stages were assigned by CT scan and EUS: carcinoma in situ (CIS; n = 1), I (n = 1), II (n = 23), III (n = 20), IV (n = 8). In 17 patients (32.1%), MIS demonstrated inaccuracies in the conventional imaging, reassigning a lower stage in 10 patients and a more advanced stage in 7 patients.

CONCLUSIONS

In 32.1% of patients with esophageal cancer, MIS changed the stage originally assigned by CT scan and EUS. Therefore, MIS should be applied to evaluate the accuracy of new noninvasive imaging methods and to assess new therapies for esophageal cancer.

A comparison study of laparoscopic versus open gastric bypass for morbid obesity

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (GBP) has been previously described, but a comparative study between laparoscopic and open GBP has not been reported. The purpose of this study was to compare surgical outcomes oflaparoscopic GBP with those of open GBP for treatment of morbid obesity.

STUDY DESIGN

From August 1998 to September 1999, we prospectively collected outcome data on 35 patients with body-mass indices between 40 kg/m2 and 60 kg/m2 who underwent laparoscopic GBP. Demographics, operative data, perioperative complications, and weight losses were collected and compared with those obtained from a retrospective chart review of 35 patients with body-mass indices between 40 kg/m2 and 60 kg/m2 who underwent open GBP before August 1998.

RESULTS

Age, gender, preoperative body-mass index, preoperative comorbidity, and earlier abdominal surgery were similar in both groups. All laparoscopic operations were completed without conversion to laparotomy. Mean operative time, operative blood loss, length of intensive care stay, and length of hospital stay were significantly less after laparoscopic GBP than after open GBP (p<0.05). There was no 30-day mortality in either group. At 1-year followup, analysis of the percentage of excess body weight loss showed no significant difference between the two groups (p<0.05).

CONCLUSIONS

Laparoscopic Roux-en-Y gastric bypass is technically feasible and safe. Laparoscopic GBP confers the clinical benefits of laparoscopy and an initial weight loss similar to that of open GBP.

Contrastive prevalence of feline retrovirus infections between northern and southern Vietnam

The prevalence of infections with three feline retroviruses; feline leukemia virus (FeLV), feline immunodeficiency virus (FIV) and feline foamy virus (FeFV), was examined in domestic cats (Felis catus) and leopard cats (Felis bengalensis) in southern Vietnam in 1998. We then compared this data with our previous study in northern Vietnam in 1997. None of the cats had FeLV antigens in both the northern and southern areas. In contrast, there is a great distinction in the seropositivity of FIV. Twenty-two percent of domestic cats had FIV antibodies whereas no FIV positive cats were detected in northern area. FIV may have entered southern Vietnam recently and spread rapidly. FeFV infections were found in both areas, suggesting that FeFV might be present in the cat populations in Vietnam from the earliest time.

Endoscopic photodynamic therapy for obstructing esophageal cancer: 77 cases over a 2-year period

BACKGROUND

Photodynamic therapy (PDT) is an alternative treatment option for the palliation of obstructive esophageal cancer. We report our experience with PDT for patients presenting with inoperable, obstructing, or bleeding esophageal cancer.

METHODS

Seventy-seven patients with inoperable, obstructing esophageal cancer were treated with PDT from November 1996 to July 1998. Photofrin (1.5-2.0 mg/kg) was administered, followed by endoscopic light treatment (630 nm red dye laser) at 48 h. Dysphagia score (1 for no dysphagia to 5 for complete obstruction), dysphagia-free interval, and patient survival were assessed.

RESULTS

Seventy-seven patients underwent 125 PDT courses. The mean dysphagia score at 4 weeks after PDT in 90.8% of the patients improved from 3.2 +/- 0.7 to 1.9 +/- 0.8 (p < 0.05). PDT adequately controlled bleeding in all six patients who had bleeding. The most common complications after the 125 PDT courses were esophageal stricture (4.8%), Candida esophagitis (3.2%), symptomatic pleural effusion (3.2%), and sunburn (10.0%). Twenty-nine patients (38%) required more than one PDT course, and seven patients required placement of an expandable metal stent for recurrent dysphagia. The mean dysphagia-free interval was 80.3 +/- 58.2 days. The median survival was 5.9 months.

CONCLUSIONS

Photodynamic therapy is a safe and effective treatment for the palliation of obstructing and bleeding esophagus cancer.

Laparoscopy or thoracoscopy for achalasia

Achalasia is an esophageal motor disorder of unknown etiology. Typical manometric findings include aperistalsis of the esophageal body coupled with elevated pressure and incomplete relaxation of the lower esophageal sphincter during swallowing. Medical treatments consist of pneumatic dilatation or injections of botulinum toxin. Surgical treatment consists of Heller's myotomy with or without an antireflux procedure. Relief of dysphagia symptoms can be achieved in 85% to 94% of patients undergoing surgical treatment. In the past decade, the minimally invasive approach for the treatment of achalasia has been proven feasible, safe, and effective. We review the role of thoracoscopy and laparoscopy and address controversies in the management of patients with achalasia.

Thoracoscopic enucleation of an esophageal leiomyoma

A series of reports in the literature suggest that video assisted thoracoscopic resection of an esophageal leiomyoma offers distinct advantage over open approach. We describe a patient with esophageal leiomyoma who underwent surgical resection via thoracoscopic approach using four thoracic trocars. The postoperative period was uneventful and the patient was discharged on postoperative day 3.

Laparoscopic umbilical herniorrhaphy

BACKGROUND

Laparoscopic technique is an alternative approach to ventral hernia repair. This study evaluated the feasibility of performing umbilical hernia repair using a single 5-mm trocar technique.

PATIENTS AND METHODS

During February 1999 to November 1999, we performed laparoscopic umbilical hernia repair in 16 consecutive patients. All operations were performed under general anesthesia. One 5-mm port was used to visualize the defect. A second 5-mm port was inserted only if there was incarcerated omentum requiring reduction. The Endo Close was inserted through a 2-mm incision made directly over the hernia to perform transabdominal closure of the defect using nonabsorbable suture.

RESULTS

The mean size of the umbilical hernia defects was 1.2 cm +/- 0.4 (range 1.0-2.0 cm). All operations were completed laparoscopically with no intraoperative or postoperative complications. The mean operative time was 35 +/- 15 minutes (range 21-75 min). All cases were performed in an outpatient setting. There have been no recurrences at a mean follow-up of 5.9 months.

CONCLUSIONS

Laparoscopic umbilical herniorrhaphy is safe and technically feasible. Its potential advantages, such as a lower rate of recurrence, will need to be validated with longer follow-up.

Subsite mapping of the human pancreatic alpha-amylase active site through structural, kinetic, and mutagenesis techniques

We report a multifaceted study of the active site region of human pancreatic alpha-amylase. Through a series of novel kinetic analyses using malto-oligosaccharides and malto-oligosaccharyl fluorides, an overall cleavage action pattern for this enzyme has been developed. The preferred binding/cleavage mode occurs when a maltose residue serves as the leaving group (aglycone sites +1 and +2) and there are three sugars in the glycon (-1, -2, -3) sites. Overall it appears that five binding subsites span the active site, although an additional glycon subsite appears to be a significant factor in the binding of longer substrates. Kinetic parameters for the cleavage of substrates modified at the 2 and 4' ' positions also highlight the importance of these hydroxyl groups for catalysis and identify the rate-determining step. Further kinetic and structural studies pinpoint Asp197 as being the likely nucleophile in catalysis, with substitution of this residue leading to an approximately 10(6)-fold drop in catalytic activity. Structural studies show that the original pseudo-tetrasaccharide structure of acarbose is modified upon binding, presumably through a series of hydrolysis and transglycosylation reactions. The end result is a pseudo-pentasaccharide moiety that spans the active site region with its N-linked "glycosidic" bond positioned at the normal site of cleavage. Interestingly, the side chains of Glu233 and Asp300, along with a water molecule, are aligned about the inhibitor N-linked glycosidic bond in a manner suggesting that these might act individually or collectively in the role of acid/base catalyst in the reaction mechanism. Indeed, kinetic analyses show that substitution of the side chains of either Glu233 or Asp300 leads to as much as a approximately 10(3)-fold decrease in catalytic activity. Structural analyses of the Asp300Asn variant of human pancreatic alpha-amylase and its complex with acarbose clearly demonstrate the importance of Asp300 to the mode of inhibitor binding.

Minimally invasive esophagectomy for Barrett's esophagus with high-grade dysplasia

BACKGROUND

Barrett's esophagus with high-grade dysplasia (BE/HGD) is associated with invasive carcinoma in 30% to 70% of cases. Esophagectomy is the treatment of choice for patients with BE/HGD but esophagectomy can be associated with high morbidity and mortality. The aim of our study was to report our preliminary experience in applying minimally invasive surgical techniques to esophagectomy for BE/HGD.

METHODS

From August 1996 to February 1999, 12 consecutive patients underwent minimally invasive esophagectomy for biopsy-proven BE/HGD. Our consort consisted of 7 men and 5 women; average age was 64 years (range, 40-78 years). All patients underwent a complete laparoscopic or combined laparoscopic and thoracoscopic resection of the esophagus with cervical anastomosis.

RESULTS

Mean operative time was 7.8 +/- 2.1 hours, mean intensive care unit stay was 2.6 +/- 2.2 days, and mean length of hospital stay was 8.3 +/- 4.7 days. Five patients (42%) had carcinoma in situ or carcinoma identified on pathologic specimen. Analyses of all resected lymph nodes in the 12 patients were negative for metastatic disease. There were 6 major complications in 5 patients: 1 patient had a small bowel perforation requiring operative repair, 2 patients needed prolonged ventilatory support for respiratory insufficiency, and 3 patients had delayed gastric emptying requiring revision of the pyloromyotomy. The single minor complication in this series was a jejunostomy tube-site infection. There were no conversions to laparotomy or thoracotomy. All patients were alive and free of metastatic disease at a mean follow-up of 12.6 months.

CONCLUSIONS

Minimally invasive esophagectomy is a feasible and safe alternative to conventional open esophagectomy for patients with BE/HGD.

Saturable ethanol binding in rat liver mitochondria

The binding of ethanol to rat liver mitochondria is shown to be saturable at physiologically relevant ethanol concentrations. This effect is reversible and is not observed in extracted mitochondrial phospholipids. Brief exposure of the mitochondria to heat abolishes saturable ethanol binding. Previously, saturable ethanol binding was reported in rat liver microsomes. Taken together, the studies indicate that saturable ethanol binding motifs may be widespread in cellular membranes. The possibility is raised that incomplete expression of the hydrophobic effect in membrane assembly results in the expression of amphipathic packing defects which display an affinity for and a sensitivity to ethanol. The presence of saturable binding modalities is reconciled with the long-standing consensus on the biodistribution of ethanol - that ethanol's interactions with tissue are negligible - on the grounds that the affinities of ethanol and of water for membranes are similar; consequently, free ethanol concentrations are insensitive to the presence of tissue despite significant ethanol binding. A fraction of the binding sites possess submillimolar affinities for ethanol consistent with published functional studies, both in vitro and in vivo, that reported submillimolar efficacies for ethanol.

Evaluation of sympathetic nerve terminals with [(11)C]epinephrine and [(11)C]hydroxyephedrine and positron emission tomography

BACKGROUND

The goal of the present study was to directly compare the new radiopharmaceutical agent [(11)C]epinephrine (EPI) with [(11)C]hydroxyephedrine (HED) through the use of PET.

METHODS AND RESULTS

Seven healthy volunteers and 10 patients were investigated after heart transplantation. PET images of both tracers were of excellent quality in the volunteers. Values for radiolabeled metabolites (measured in percent of blood activity) at 5, 20, and 60 minutes after injection were approximately 35%, approximately 82%, and approximately 86% for EPI and approximately 13%, approximately 47%, and approximately 78% for HED, respectively. At 35 minutes, metabolite-corrected mean myocardial retention fraction of EPI (0. 235+/-0.022 min(-1)) was significantly greater (P<0.01) than that of HED (0.142+/-0.012 min(-1)). Corrected tracer retention fractions of both EPI and HED were significantly reduced in transplant recipients (0.055+/-0.004 min(-1), P<0.0001; and 0.050+/-0.006 min(-1), P<0. 0001, respectively) compared with volunteers. Normalization of retention fractions of patients with transplantation within 1 year to volunteers resulted in a value (ratio expressed in percent) of 20. 6+/-1.8% for EPI, significantly (P<0.03) smaller than 27.8+/-0.8% for HED. In patients with transplantation later than 1 year, the values were 26.0+/-2.9% for EPI compared with 44.2+/-5.6% for HED (P<0.014).

CONCLUSIONS

Both tracers showed high selectivity for neuronal uptake in the heart, with a significant reduction in tracer retention in transplant recipients compared with volunteers. Compared with HED, EPI showed greater retention in volunteers and a lower retention ratio in transplant recipients, suggesting that EPI may be the superior tracer with higher sensitivity to neuronal abnormalities. Because EPI reflects neuronal uptake, metabolism, and storage, it may be more suitable for the study of neuronal integrity than HED, which primarily traces uptake-1 capacity.

Hypopharyngeal perforation during laparoscopic Roux-en-Y gastric bypass

Laparoscopic Roux-en-Y gastric bypass was recently introduced as an alternative surgical treatment for morbid obesity. The technique involves placement of a 21-mm anvil transorally down to the gastric pouch for creation of the gastroenterostomy anastomosis using an EEA stapler placed transabdominally. Esophageal injury is a theoretical concern with transoral manipulation of the anvil. The authors present a case of hypopharyngeal perforation after an attempted transoral insertion of an EEA anvil. The perforation was treated with neck exploration and drainage. We discuss the mechanism of injury and alternative method for placement of the gastric anvil.

Acoustic streaming in micromachined flexural plate wave devices: numerical simulation and experimental verification

This paper presents the numerical simulation and experimental validation of acoustic streaming in micromachined flexural plate wave (FPW) devices. Two-dimensional and three-dimensional models of two device types were considered: the classical device with parallel interdigitated electrodes and the focused device with curved electrodes. Influences of different parameters on the time-averaged velocity were investigated. Thermal transport effects of the acoustic streaming were also considered. We observed the amplifying effect of the streaming in the second type numerically and experimentally. To verify simulation results, the method of the particle image velocimetry (PIV) was applied in the experimental investigation.

Comparison of prevalence of feline herpesvirus type 1, calicivirus and parvovirus infections in domestic and leopard cats in Vietnam

A serosurvey of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), and feline parvovirus (FPV) in cats from Ho Chi Minh City area in southern Vietnam was conducted in December 1998, and we compared the results with our previous results in northern Vietnam (Hanoi area). The positive rate of FHV and FCV in domestic cats were 44% and 74%, respectively. They were rather higher than those in Hanoi area, while the seropositivity of FPV (44%) was similar to that in Hanoi area. In leopard cats, the positive rate of FPV was high (3/4) and it indicated that FPV was prevailing in leopard cats in Vietnam.

Laparoscopic Roux-en-Y gastric bypass for super/super obesity

Laparoscopic gastric bypass has been recently introduced as an alternative method to conventional open gastric bypass. This procedure has been generally limited to patients with a BMI <60 kg/m2 due to the possible technical limitations of the laparoscopic instruments. In this article, we present a patient with super/super obesity (61 kg/m2) who underwent Rouxen-Y gastric bypass using the laparoscopic approach.

Effect of open and laparoscopic surgery on cellular immunity in a swine model

Immune suppression associated with trauma has been demonstrated to be proportional to the magnitude of injury. Laparoscopic surgery has been shown to produce a diminished stress response compared to open surgery. Postoperative immune function, specifically cellular immunity, may be better preserved after laparoscopic surgery compared to open surgery. The aim of this study was to examine the effect of open versus laparoscopic surgery on cellular immunity in a swine model. Twenty domestic female pigs were randomly selected for laparoscopic cholecystectomy (LC) or open cholecystectomy (OC). Cellular immune functions were evaluated with delayed-type hypersensitivity (DTH) skin test and serial phytohemoagglutinin (PHA)-induced T-cell proliferation of the peripheral blood. There was a significant reduction in PHA-induced T-cell proliferation in both LC and OC groups on days 1 and 3 compared to preoperative values (p < 0.05). The reduction of mitogen-induced T-cell proliferation after LC was significantly less than after OC on day 1 (p = 0.03). The mean DTH reaction was 29.7 +/- 3.7 mm2 in the LC group compared to 13.9 +/- 1.2 mm2 in the OC group (p < 0.001). There was no difference in postoperative white blood count values between the two groups. Suppression of cellular immunity occurred after both LC and OC. The magnitude and duration of impaired cellular immunity after laparoscopic surgery was less than after open surgery as measured by T-cell proliferation and DTH response.

Photodynamic therapy for treatment of malignant dysphagia

Photodynamic therapy (PDT) was recently approved by the Food and Drug Administration for palliating obstructing esophageal cancer. This report reviews our initial experience using PDT to treat malignant dysphagia. Patients with inoperable, obstructing esophageal cancer were considered for PDT. Photofrin was injected 48 hours before endoscopic laser activation. Dysphagia score was assessed. Thirty patients underwent 53 PDT courses. Improvement in dysphagia occurred in 83%. Mean dysphagia score decreased from 2.8 to 1.8 (p < 0.05). Complications included esophageal stricture (9.4%), candida esophagitis (5.7%), symptomatic pleural effusion (5.7%), contained esophageal perforation (1.9%), aspiration pneumonia (1.9%), and sunburn (13.2%). Seventeen patients (57%) required more than one PDT treatment, and in 10 an expandable metal stent was used as an adjunct. The 30-day mortality rate was 7%. PDT is effective in palliating patients with malignant dysphagia. The ideal patient for PDT has an obstructing, primarily endoluminal esophageal tumor with minimal extrinsic compression.

One and the same androgen for all? Towards designer androgens

The introduction of designer oestrogens as a treatment modality in hormone replacement in women has invited to consider the concept of compounds with selective androgenic effects for male hormone replacement therapy. The full spectrum of the actions of testosterone may not be necessary of even undesired for certain indications for testosterone treatment. To define for what indications certain androgenic properties are desired and undesired more insight in basic androgen (patho)physiology is required. There is convincing evidence that aromatization of androgenic compounds to oestrogens might be an advantage for maintenance of bone mass and it might also mitigate negative effects of androgens on biochemical parameters of cardiovascular risks; the potentially negative effects of oestrogens on prostate pathology in ageing men needs further elucidation. While the role of dihydro-testosterone (DHT) for the male sexual differentiation and for pubertal sexual maturation is evident, its role in mature and ageing males seems less significant or may even be harmful. It is, however, of note that a negative effect of DHT on prostate pathophysiology is certainly not proven. For male contraception a progestational agent with strong androgenic properties might be an asset. For most of the androgenic actions the critical levels of androgens are not well established. The latter is relevant since the large amount of androgen molecules required for its biological actions (as compared to oestrogens) is an impediment in androgen replacement modalities. There may be room for more biopotent androgens since delivery of large amounts of androgen molecules to the circulation poses problems for treatment modalities.

Sugar ring distortion in the glycosyl-enzyme intermediate of a family G/11 xylanase

The 1.8 A resolution structure of the glycosyl-enzyme intermediate formed on the retaining beta-1,4-xylanase from Bacillus circulans has been determined using X-ray crystallographic techniques. The 2-fluoro-xylose residue bound in the -1 subsite adopts a 2,5B (boat) conformation, allowing atoms C5, O5, C1, and C2 of the sugar to achieve coplanarity as required at the oxocarbenium ion-like transition states of the double-displacement catalytic mechanism. Comparison of this structure to that of a mutant of this same enzyme noncovalently complexed with xylotetraose [Wakarchuk et al. (1994) Protein Sci. 3, 467-475] reveals a number of differences beyond the distortion of the sugar moiety. Most notably, a bifurcated hydrogen bond interaction is formed in the glycosyl-enzyme intermediate involving Heta of Tyr69, the endocyclic oxygen (O5) of the xylose residue in the -1 subsite, and Oepsilon2 of the catalytic nucleophile, Glu78. To gain additional understanding of the role of Tyr69 at the active site of this enzyme, we also determined the 1.5 A resolution structure of the catalytically inactive Tyr69Phe mutant. Interestingly, no significant structural perturbation due to the loss of the phenolic group is observed. These results suggest that the interactions involving the phenolic group of Tyr69, O5 of the proximal saccharide, and Glu78 Oepsilon2 are important for the catalytic mechanism of this enzyme, and it is proposed that, through charge redistribution, these interactions serve to stabilize the oxocarbenium-like ion of the transition state. Studies of the covalent glycosyl-enzyme intermediate of this xylanase also provide insight into specificity, as contacts with C5 of the xylose moiety exclude sugars with hydroxymethyl substituents, and the mechanism of catalysis, including aspects of stereoelectronic theory as applied to glycoside hydrolysis.

Sequence comparison of the VP2 variable region of infectious bursal disease virus isolates from Vietnam

The variable region in the VP2 gene of twenty-three infectious bursal disease virus (IBDV) isolates, collected in Vietnam in 1997 and 1998, was amplified as cDNA by using the reverse transcription-polymerase chain reaction and sequenced. Analysis of amino acid substitutions and phylogenetic relationships of the deduced amino acid sequences (residues 206-350) showed that the nineteen Vietnamese vv IBDVs clustered with the European vv IBDVs, Japanese vv IBDVs and Chinese vv strains, and that the four vietnamese virulent strains were closely related to European virulent strain 52/70. These results suggest that Vietnamese vv IBDVs, European vv IBDVs, Japanese vv IBDVs and Chinese vv strains have the same origin.

Pulmonary embolism following laparoscopic antireflux surgery: a case report and review of the literature

Deep venous thrombosis and pulmonary embolism are concerning causes of morbidity and mortality in patients undergoing general surgical procedures. Laparoscopic surgery has gained rapid acceptance in the past several years and is now a commonly performed procedure by most general surgeons. Multiple anecdotal reports of pulmonary embolism following laparoscopic cholecystectomy have been reported, but the true incidence of deep venous thrombosis and pulmonary embolism in patients undergoing laparoscopic surgery is not known. We present a case of pulmonary embolism following laparoscopic repair of paraesophageal hernia. The literature is then reviewed regarding the incidence of pulmonary embolism following laparoscopic surgery, the mechanism of deep venous thrombosis formation, and the recommendations for deep venous thrombosis prophylaxis in patients undergoing laparoscopic procedures.

Laparoscopic Roux-en-Y gastric bypass for morbid obesity

Surgery is currently the only effective treatment for morbid obesity. The two most commonly accepted operations are the Roux-en-Y gastric bypass and vertical banded gastroplasty. Although multiple authors have reported on a laparoscopic approach to gastric banding, the Roux-en-Y gastric bypass is a complex operation to be replicated using laparoscopic techniques. In this article, we describe our technique of the Roux-en-Y gastric bypass using a laparoscopic approach in four cases.

Detection of micrometastases in histologically negative lymph nodes in esophageal cancer

BACKGROUND

New molecular techniques may identify micrometastases in histologically negative lymph nodes and have an impact on the staging of esophageal cancer. We investigated the role of the reverse transcriptase-polymerase chain reaction (RT-PCR) assay to identify micrometastases in esophageal cancer.

METHODS

The RT-PCR assay to detect carcinoembryonic antigen (CEA) messenger ribonucleic acid (mRNA) was performed on lymph nodes from patients with esophageal cancer and benign esophageal disorders. The presence of CEA mRNA in lymph nodes was considered evidence of metastases.

RESULTS

Histopathologic study revealed metastases in 50 (41%) of 123 lymph nodes from 30 patients with esophageal cancer. All histologically positive lymph nodes contained CEA mRNA by RT-PCR. Of 73 histologically negative lymph nodes, 36 (49%) contained CEA mRNA, a significant increase compared with the histopathologic diagnosis (p < 0.001). Lymph nodes in patients with benign disease contained no CEA mRNA. In 10 patients, histologic stage was NO. Five of them were also negative by RT-PCR, and all are alive with only one recurrence. In the remaining 5 patients, RT-PCR was positive for occult lymph node metastases; 2 have died of disease, and 1 is alive with recurrent disease.

CONCLUSIONS

In patients with esophageal cancer, RT-PCR detects more lymph node metastases than does histopathology. Initial follow-up suggests a positive RT-PCR with negative histologic findings may have poor prognostic implications. Further studies will be needed to confirm any clinical implications.

The etiology of bacterial pneumonia and meningitis in Vietnam

BACKGROUND

To date no studies on the incidence of Haemophilus influenzae type b (Hib) disease, Hib carrier rates in infants and children or the proportion of bacterial meningitis cases caused by Hib in Vietnam have been performed. The availability of safe and highly effective Hib vaccines makes such information important.

METHODS

The bacterial etiology of a sample of infants and children with pneumonia and meningitis seen at Pediatric Hospital No. 1 in Ho Chi Minh City was studied by culture and latex agglutination of blood, cerebrospinal fluid, urine and pleural fluid. The carriage rate of pneumococci and Hib was studied in a sample of outpatient children.

RESULTS

Hib caused 53% of 34 culture-proven bacterial meningitis cases and pneumococci caused 18%. Of 31 meningitis cases diagnosed by latex agglutination, 39% were caused by Hib and 55% by pneumococci. Ninety percent of cases of Hib meningitis occurred in children <1 year of age. Fifty percent of meningitis cases were associated with acute respiratory infection. In 213 bacteremic pneumonia cases 92.5% of blood cultures grew Streptococcus pneumoniae and only 1% grew Hib. The carrier rate of Hib in outpatients <5 years of age with upper respiratory tract infection increased from 2% to 7.6% between 1993 and 1996.

CONCLUSION

Hib is the most frequent cause of meningitis in infants and children admitted to hospitals in South Vietnam. Ninety percent of Hib meningitis cases occur in patients < 1 year of age. Bacteremic Hib pneumonia in Vietnam is rare. The results suggest that Hib is the major cause of meningitis in Vietnam but do not permit conclusions regarding its true incidence. The carrier rate of Hib in children <5 years of age in Vietnam has increased to approximately 7% since 1993.

Coagulation modifications after laparoscopic and open cholecystectomy in a swine model

BACKGROUND

The stress response to surgical trauma precipitates a state of transient hypercoagulation. Studies have demonstrated that laparoscopic surgery results in a diminished stress response compared to open surgery. The aim of this study was to determine the extent of postoperative hypercoagulability following laparoscopic cholecystectomy (LC) compared to open cholecystectomy (OC).

METHODS

Twenty-one pigs were randomly selected to undergo LC (N = 10) or OC (N = 11). Whole blood was collected preoperatively and on postoperative days (PODs) 1, 2, and 3 for determination of viscoelastic changes using a thromboelastography (TEG) coagulation analyzer. Four parameters were calculated from the TEG: R (reaction time), K (coagulation time), alpha (rate of clot formation), and MA (maximal amplitude). Antithrombin III (AT III) level was measured preoperatively and on POD 1.

RESULTS

After OC, three of four TEG parameters changed to reflect a state of hypercoagulation. Only MA values were significantly changed after LC. Comparison between OC and LC showed no difference in the TEG parameter. There was no significant change in AT III levels after LC or OC.

CONCLUSIONS

OC results in postoperative hypercoagulation typically encountered in open abdominal surgery. Although there were no differences in TEG or AT III between the two groups, after the laparoscopic approach all but one TEG parameter remained unchanged, suggesting a diminished hypercoagulable state. By reducing postoperative hypercoagulation, laparoscopic surgery may reduce the risk of developing postoperative venous thrombosis.

Preliminary results of thoracoscopic Belsey Mark IV antireflux procedure

Laparoscopic Nissen fundoplication has replaced open approaches for refractory gastroesophageal reflux disease (GERD) in many major medical centers. Here we report our preliminary results of the Belsey Mark IV antireflux procedure performed by video-assisted thoracoscopy (VATS-Belsey). Fifteen patients underwent VATS-Belsey. The indications for surgery included GERD refractory to medical therapy (n=10), achalasia (n=2), diffuse esophageal spasms (n=1), epiphrenic esophageal diverticulum (n=1), and paraesophageal hernia (n=1). The median operative time was 235 min. There were three conversions to open minithoracotomy (8-10 cm) necessitated by severe adhesions (n=2) and repair of a gastric perforation (n=1). The median hospital stay was 4 days. Postoperative complications included persistent air leaks, requiring discharge with a Heimlich valve in one patient. There were no perioperative deaths. At a median follow-up of 19 months, ten patients (66%) were asymptomatic and were not taking any antacids. One patient who had taken proton pump inhibitors preoperatively required postoperative H2 blockers for mild heartburn. In three patients, recurrent GERD symptoms (mean follow-up 6 months) led to laparoscopic takedown of the Belsey and Nissen fundoplication. One patient with achalasia, who had recurrent dysphagia after 1 year of relief following VATS myotomy and Belsey, underwent esophagectomy. The Belsey Mark IV antireflux procedure is technically feasible by VATS with minimal morbidity. However, our preliminary results suggest that open thoracotomy for Belsey Mark IV should remain the standard operation for GERD with poor esophageal motility when a thoracic approach is desired. We have modified our approach to laparoscopic partial fundoplications (Toupet or Dor) for severe GERD and poor esophageal motility when an abdominal approach is possible.

Structural and spectroscopic studies of azide complexes of horse heart myoglobin and the His-64-->Thr variant

The high-resolution X-ray crystallographic structures of horse heart azidometmyoglobin complexes of the wild-type protein and the His-64-->Thr variant have been determined to 2.0 and 1.8 A respectively. Azide binds to wild-type metmyoglobin in a bent configuration with an Fe-N-1-N-3 angle of 119 degrees and is oriented into the distal crevice in the direction of Ile-107. The proximity of the His-64 NE2 atom to the N-1 atom of the bound azide indicates stabilization of the ligand by the His-64 side chain through hydrogen bonding. In addition, structural characterization of wild-type horse heart azidometmyoglobin establishes that the only structural change induced by ligand binding is a small movement of the Leu-29 side chain away from the azide ligand. EPR and Fourier transform infrared spectroscopy were used to characterize the myoglobin azide complexes further. EPR spectroscopy revealed that, in contrast with wild-type azidometmyoglobin, two slightly different low-spin species are formed by azide bound to the His-64-->Thr variant both in solution and in a polycrystalline sample. One of these low-spin species has a greater relative intensity, with g values very similar to those of the azide complex of the wild-type protein. These EPR results together with structural information on this variant indicate the presence of two distinct conformations of bound azide, with one form predominating. The major conformation is comparable to that formed by wild-type myoglobin in which azide is oriented into the distal crevice. In the minor conformation the azide is oriented towards the exterior of the protein.

Minimally invasive approach to esophagectomy

BACKGROUND

Recent advances in laparoscopic and thoracoscopic surgery have made it possible to perform esophagectomy using minimally invasive techniques. The aim of this report was to present our preliminary experience with minimally invasive esophagectomy.

METHODS

We reviewed our experience on eight patients who underwent minimally invasive esophagectomy using either laparoscopic and/or thoracoscopic techniques from June 1996 to May 1997. Indications for esophagectomy included stage I carcinoma (5), palliative resection (1), Barrett's with high grade dysplasia (1) and end stage achalasia (1).

RESULTS

The average age was 68 years (54-82). The surgical approach to esophagectomy included laparoscopic transhiatal esophagectomy with cervical anastomosis (n = 4), thoracoscopic and laparoscopic esophagectomy with cervical anastomosis (n = 1), and laparoscopic mobilization with right mini-thoracotomy and intra-thoracic anastomosis (n = 3). Conversion to mini-laparotomy was required in two patients (25%) to complete esophageal dissection and facilitate gastric pull-up. The mean operative time was 460 minutes. The mean intensive care stay was 1.9 days (range of 0-7 days) with a mean hospital stay of 13.8 days. Minor complications included atrial fibrillation (n = 1), pleural effusion (n = 2) and persistent air leak (n = 1). Major complications included cervical anastomotic leak (n = 1), and delayed gastric emptying requiring pyloroplasty (n = 1). There was no perioperative mortality.

CONCLUSIONS

This preliminary experience suggests that minimally invasive esophagectomy is safe and feasible in centers with experience in advanced minimally invasive surgical procedures. Further studies are necessary to determine advantages over open esophagectomy.

Laparoscopic transhiatal esophagectomy for Barrett's esophagus with high grade dysplasia

BACKGROUND

A number of case reports have described the application of minimally invasive surgical techniques to accomplish esophagectomy. However, most reports have employed thoracoscopic or laparoscopic techniques to perform esophagectomy in addition to an "access" incision which often approaches a standard laparotomy or thoracotomy.

CASE REPORT

This report describes a total laparoscopic transhiatal esophagectomy in a 55 year old female with Barrett's esophagus and high grade dysplasia.

CONCLUSIONS

The patient had an uneventful recovery and was discharged home on the fourth day after a total laparoscopic esophagectomy. This report demonstrates the technical feasibility of this complex procedure by a minimally invasive approach.

Characterization of Lnk. An adaptor protein expressed in lymphocytes

Stimulation of the T cell antigen receptor (TCR) activates a set of non-receptor protein tyrosine kinases that assist in delivering signals to the cell interior. Among the presumed substrates for these kinases, adaptor proteins, which juxtapose effector enzyme systems with the antigen receptor complex, figure prominently. Previous studies suggested that Lnk, a 38-kDa protein consisting of a single SH2 domain and a region containing potential tyrosine phosphorylation sites, might serve to join Grb2, phospholipase C-gamma1, and phosphatidylinositol 3-kinase to the TCR. To elucidate the physiological roles of Lnk in T cell signal transduction, we isolated the mouse Lnk cDNA, characterized the structure of the mouse Lnk gene, and generated transgenic mice that overproduce Lnk in thymocytes. Here we report that although Lnk becomes phosphorylated during T cell activation, it plays no limiting role in the TCR signaling process. Moreover, we have distinguished p38(Lnk) from the more prominent 36-kDa tyrosine phosphoproteins that appear in activated T cells. Together these studies suggest that Lnk participates in signaling from receptors other than antigen receptors in lymphocytes.