Cost, performance, and reliability simulator for optical transceiver modules

The program couple combines simulators for optical performance, mechanical reliability, and production cost under a graphical-user interface to design, simulate, and evaluate micro-optomechanical structures. The thermal simulator predicts the package temperature distribution on the basis of the materials and the geometry as well as on heat sources, sinks, and boundary conditions. The thermal distribution is input to the mechanical simulator, which calculates the stresses or strains and displacements caused by differential thermal expansion. The optical simulator predicts the impact on the optical efficiency and the cross talk of mechanical and optical parameter variations such as solder heights, misalignments, and wavelength distributions. The cost simulator represents the manufacturing process flow and calculates the final cost and the cost sensitivity on basis of the cost and the yield of each process step. By means of balancing detector and coupling yield, cosimulation from optical to cost domains determines the optimum detector size to produce the lowest-cost transceiver module.

Local treatment of abdominal wound reduces tumor implantation

BACKGROUND AND OBJECTIVES

Pneumoperitoneum increases the trocar-site tumor implantation rate using a human colon cancer cell line in a hamster model. The purpose of this study was to determine whether local treatment of trocar sites with potential tumoricidal agents can inhibit tumor implantation after pneumoperitoneum.

METHODS

GW-39 human colon cancer cells (0.5 ml of 2.5% v/v; 8.0 x 10(5) cells) were injected throughout the abdomen of 133 Golden Syrian hamsters through a midline incision. The animals were randomized to receive either untreated 5-mm trocars in each abdominal quadrant (group I control, n = 49), trocars dipped in 10% povidone-iodine (group II, n = 53), or trocars coated with 1% silver sulfadiazine (group III, n = 51). The midline wounds were also coated with the respective agents before closing. Pneumoperitoneum was then maintained at 10 mmHg for 10 min, after which the trocar wounds were closed. In group II, the trocar sites were treated with a coat of povidone-iodine after the trocars were withdrawn and before closing. Gross and microscopic tumor implants were analyzed at 7 weeks postoperatively.

RESULTS

The rate of tumor cell implantation at trocar sites was reduced from 93% (172/184) in the control group to 75% (126/168) and 78% (141/180) in groups II and III, respectively (P < 0.0001). Fewer palpable tumors were detected in groups II and III (40% and 23%, respectively) than in the control group (72%, P < 0.0001). Mean tumor mass in group III (0.4+/-0.1 g), but not in group II (1.0+/-0.2 g), was significantly less than that in the control group (1.3+/-0.1 g, P < 0.01). Overall tumor involvement of the larger midline wound was similar for all groups (I = 80%, II = 79%, III = 71%). However, palpable tumors were identified more frequently in group I (67%) than in groups II and III (43%, P < 0.05; 22%, P < 0.01, respectively).

CONCLUSION

Pretreatment of abdominal wounds with povidone-iodine or silver sulfadiazine can reduce tumor implantation after pneumoperitoneum in a hamster model.

Excision of trocar sites reduces tumor implantation in an animal model

PURPOSE

The purpose of this study was to determine the effect of excising abdominal trocar wound sites after pneumoperitoneum on the rate of trocar site tumor implantation in a hamster model. This would help determine whether tumor cells seed trocar sites during or after pneumoperitoneum.

METHODS

A total of 0.5 ml of GW-39 human colon cancer cell suspension at 2.5 percent v/v (8 x 10(5) cells) was injected into the abdomens of 77 hamsters through a midline incision. Animals were subjected to ten minutes of pneumoperitoneum, after placement of four abdominal trocars, and then randomly assigned to undergo either simple suture closure or 4-mm radius trocar wound site excision at the end of the procedure. Gross and microscopic tumor implants were documented seven weeks later.

RESULTS

There were three and four deaths in simple suture closure and wound site excision groups, respectively. Of the remaining 35 hamsters in each group, tumor cells implanted at 89 and 78 percent of trocar sites, respectively (P < 0.03). There was no significant difference between the two groups in tumor implantation at midline laparotomy sites. Wound site excision also resulted in fewer palpable tumors (44 vs. 61 percent; P < 0.01) and a lower tumor implantation rate (49 vs. 74 percent; P < 0.05) at all four concurrent sites compared with simple suture closure.

CONCLUSIONS

Excision of laparoscopic abdominal trocar wound sites can significantly, but not completely, reduce tumor implantation rate compared with simple wound closure.

Production and systemic absorption of toxic byproducts of tissue combustion during laparoscopic cholecystectomy

Among the potential hazards of laparoscopic surgery using electrocautery is the release of chemical by-products of incomplete tissue combustion into the pneumoperitoneum with subsequent transperitoneal absorption into the bloodstream and/or release into the operating room. The purpose of this study of patients undergoing laparoscopic cholecystectomy (LC) was twofold: (1) to assess the relationship between intraperitoneal concentration of carbon monoxide (CO) and blood levels of carboxyhemoglobin (COHb) and methemoglobin (MetHb), and (2) to assess the surgeon's inhalation of CO resulting from ambient smoke exposure. During LC with monopolar electrocautery, 21 patients were evaluated intraoperatively for intraperitoneal [CO] by sampling gas from a trocar, whereas arterial [COHb) and [MetHb] were determined perioperatively. The surgeon's venous blood was drawn pre- and postoperatively to assay [COHb] and [MetHb]. Patients completed visual analogue questionnaires 6 hours and 24 hours postoperatively to assess for adverse symptoms. Mean (+/- SEM) patient age and weight were 45 +/- 3 years and 84 +/- 4 kg, respectively. Mean duration of the operation was 69 +/- 5 minutes, and electrocautery was used for 3.0 +/- 0.3 minutes. Intraperitoneal [CO] rose to peak levels of 209 +/- 19 ppm at 50 minutes, whereas systemic [COHb] and [MetHb] were unchanged. The surgeon's systemic [COHb] and [MetHb] did not increase postoperatively. Nausea, abdominal pain, and fatigue scores decreased significantly between 6 and 24 hours postoperatively; however, there were no correlations between these symptoms and peak intraperitoneal [CO]. Although LC using electrocautery increases intraperitoneal [CO] to "hazardous" levels, systemic [COHb] and [MetHb] are not elevated by generation of intraperitoneal smoke. The surgeon's exposure to CO by the evacuation of smoke through laparoscopic ports is negligible. Production of smoke during LC using monopolar electrocautery, therefore, does not appear to pose a threat to either the patient or the surgeon.

Choroidal involvement in Wegener's granulomatosis: a case report

Wegener's granulomatosis is a necrotizing, granulomatous vasculitis. It usually causes sinusitis, pneumonitis and glomerulonephritis. The common ocular manifestations include conjunctivitis, scleritis, peripheral keratitis and orbital inflammation. We report the case of a 50-year-old woman with Wegener's granulomatosis and very severe ocular complications who underwent bilateral enucleation. The pathologic findings of the eyeballs revealed granulomatous necrotizing scleritis, perivasculitis and granulomatous choroiditis. The last, as far as we know, has not yet been reported.

Endoscopic axillary lymph node dissection: an experimental study in human cadavers

BACKGROUND

The role of axillary lymph node dissection in the staging of patients with breast carcinoma is currently under evaluation. As a result of recent advances in minimally invasive techniques, an endoscopic approach to axillary lymph node dissection may be an attractive alternative to lymphadenectomy performed via a standard "open" axillary incision. The purpose of the present study was to evaluate the technical feasibility and safety of such an approach in human cadavers.

STUDY DESIGN

Twelve axillary dissections (right in seven, left in five) were performed in seven cadavers. A 2.5-cm incision was made along the lateral chest wall 12 cm inferior to the apex of the axilla. The subcutaneous axillary space was expanded with a balloon dissector, and exposure was maintained with a prototype external lift device. Endoscopic dissection was performed with three or four 5-mm ports inserted into this space. Histologic analysis was performed to document the number of lymph nodes removed.

RESULTS

The mean dissection time for endoscopic axillary lymphadenectomy was 56.7+/-19 minutes (range, 30-90 minutes). Structures visualized endoscopically included the axillary vein (12 of 12 patients), the long thoracic nerve (12 of 12 patients), the thoracodorsal nerve (10 of 12 patients), and the intercostobrachial nerve (11 of 12 patients). An average of 9.9+/-7.2 lymph nodes (range, 2-22 nodes) was removed from each axilla. Open exploration of the axilla after the endoscopic dissection confirmed no injuries to any neurovascular structures. Residual lymph nodes were removed from the axilla in 7 of 12 dissections (58%; average, 4.2+/-4.0 nodes per specimen).

CONCLUSIONS

These results suggest that endoscopic axillary dissection is feasible with currently available technology. Clinical trials in patients with breast carcinoma may be warranted to evaluate this technique further.

Identification of genes expressed in human CD34(+) hematopoietic stem/progenitor cells by expressed sequence tags and efficient full-length cDNA cloning

Hematopoietic stem/progenitor cells (HSPCs) possess the potentials of self-renewal, proliferation, and differentiation toward different lineages of blood cells. These cells not only play a primordial role in hematopoietic development but also have important clinical application. Characterization of the gene expression profile in CD34(+) HSPCs may lead to a better understanding of the regulation of normal and pathological hematopoiesis. In the present work, genes expressed in human umbilical cord blood CD34(+) cells were catalogued by partially sequencing a large amount of cDNA clones [or expressed sequence tags (ESTs)] and analyzing these sequences with the tools of bioinformatics. Among 9,866 ESTs thus obtained, 4,697 (47.6%) showed identity to known genes in the GenBank database, 2, 603 (26.4%) matched to the ESTs previously deposited in a public domain database, 1,415 (14.3%) were previously undescribed ESTs, and the remaining 1,151 (11.7%) were mitochondrial DNA, ribosomal RNA, or repetitive (Alu or L1) sequences. Integration of ESTs of known genes generated a profile including 855 genes that could be divided into different categories according to their functions. Some (8.2%) of the genes in this profile were considered related to early hematopoiesis. The possible function of ESTs corresponding to so far unknown genes were approached by means of homology and functional motif searches. Moreover, attempts were made to generate libraries enriched for full-length cDNAs, to better explore the genes in HSPCs. Nearly 60% of the cDNA clones of mRNA under 2 kb in our libraries had 5' ends upstream of the first ATG codon of the ORF. With this satisfactory result, we have developed an efficient working system that allowed fast sequencing of 32 full-length cDNAs, 16 of them being mapped to the chromosomes with radiation hybrid panels. This work may lay a basis for the further research on the molecular network of hematopoietic regulation.

A population-based study of the prevalence and associated factors of diabetes mellitus in southern Taiwan

Diabetes mellitus is one of the major health care problems in Taiwan, since the mortality rate has increased from 7.91 per 100,000 in 1980 to 35.1 per 100,000 in 1996. To determine the prevalence of diabetes in southern Taiwan and to investigate possible associated factors, a stratified systematic cluster sampling of 1638 subjects (780 men and 858 women) aged > or =20 years living in Tainan city was investigated with a standard 75-g oral glucose tolerance test. The crude prevalence of diabetes in Tainan was 9.0% (10.3% men and 7.9% women) and the age-adjusted prevalence was 9.2% (10.4% men and 8.1% women). The crude prevalence of IGT was 14.0% (13.8% men and 14.1% women), and the age-adjusted prevalence was 15.5% (15.0% men and 15.9% women). The prevalence of diabetes by using the revised new diagnostic criteria was 7.5%. The prevalence of diabetes and IGT increased significantly with age for both genders, although the rises in prevalence of IGT in women was less consistent. Diabetic and IGT subjects were older and had higher levels of BMI, triglyceride, systolic and diastolic blood pressure, and higher prevalence of obesity, hypertension, and dyslipidemia but indulged in less physical activity than non-diabetic subjects. The significant factors associated with the newly diagnosed diabetes were age, family history of DM, BMI, systolic blood pressure, physical activity, and serum triglyceride levels.

Incidence of neoplastic polyps in the ileal pouch of patients with familial adenomatous polyposis after restorative proctocolectomy

PURPOSE

Although adenomatous polyps and even adenocarcinomas have been found in the terminal ileum of patients with familial adenomatous polyposis, the prevalence of neoplastic changes in the pouches of patients who have undergone restorative proctocolectomy is unknown. The objective of this study was to determine the frequency of pelvic pouch neoplasia in familial adenomatous polyposis patients after restorative proctocolectomy.

METHODS

Patients in a polyposis registry who had undergone restorative proctocolectomy were recruited. Demographic, surgical, pathologic, and endoscopic data were obtained from patient records. Video pouchoscopy was done after two enemas and representative biopsies were taken.

RESULTS

Of 102 eligible patients, 26 (17 males and 9 females) participated. Median age at ileal pouch-anal anastomosis was 31 (range, 12-58) years. Median follow-up period was 66 (11-156) months. Adenomas were found in the pouch of 11 (42 percent) patients, in the terminal ileum above the pouch in 1 patient, and in the anal canal of 4 patients. Among patients with pouch polyps, three patients had one lesion, three patients had two lesions, and five patients had more than ten lesions. The incidence of polyps increased steadily with time from restorative proctocolectomy. There was no relation between the incidence of pouch polyposis and the severity of colonic or duodenal disease.

CONCLUSIONS

Proctocolectomy and ileal pouch-anal anastomosis is associated with a significant risk of pouch neoplasia in familial adenomatous polyposis patients. The severity of pouch adenomas was not related either to the severity of colonic or duodenal disease. The pelvic pouches of all patients with familial adenomatous polyposis who have undergone restorative proctocolectomy should be examined periodically.

The evolution and maturation of laparoscopic cholecystectomy in an academic practice

BACKGROUND

The technique of laparoscopic cholecystectomy (LC) has evolved since its adoption in the late 1980s. We sought to document these changes and assess whether patient outcomes were influenced during this maturational process.

STUDY DESIGN

A prospective data base was used to record the outcomes of all LCs performed in an academic surgeon's practice. Trends over time among 1,165 consecutive patients were assessed by comparing the first 100 LCs (group I), the middle 100 LCs (group II), and the most recent 100 LCs (group III).

RESULTS

During a 93-month period with 1,165 patients undergoing LC, 25 procedures (2.1%) were converted to open cholecystectomy. Perioperative complications occurred in 31 patients (3%): grade I in 9 (0.8%), grade II in 16 (1.4%), grade III in 5 (0.4%), and grade IV (death) in 1 (0.1%). Length of hospital stay and convalescence were 1.1 +/- 0.1 and 9.5 +/- 0.5 days, respectively. Nineteen patients (2%) were readmitted early after operation and 10 (1%) developed long-term complications (port-site hernia or retained stone). In group III, cholangiography was largely replaced by intraoperative ultrasonography for ductal evaluation. Operating room time decreased, while the rates of conversion, morbidity, and readmission remained the same. Patients had higher ASA classifications in the latter two groups, whereas operative charges were greater in Group III than in Groups I and II. These trends occurred even though most procedures are currently performed by residents, and fewer LCs are being done.

CONCLUSIONS

Laparoscopic cholecystectomy has matured into a more efficient operation, yet remains safe with low morbidity when performed by residents at an academic institution.

[Morphological evidence for thymocytes apoptosis outside the thymus]

In vitro thymus explants culture designed in this paper can mimic the thymic microenvironment as it were in vivo. Theoretically, thymus explants are cut off free from blood stream. So if some developing or developed thymocytes had the inclination to migrate into the periphery, they would only be accumulated in the blood vessels within thymus explants. After 3-day's culture, under transmission electron microscope we observed the migrating thymocytes accumulated in the blood vessels of C57BL/6 mice thymus explants, and these thymocytes were occurring apoptosis at different stage. To our knowledge, this findings offers the first morphological evidence that thymocytes do not necessarily die inside the thymus in situ, and that having acquired the death signals thymocytes can migrate into the blood stream and die quickly outside the thymus. But this is not to say that we deny the intrathymic death hypothesis. On the contrary, we found the number of thymocytes occurring in situ apoptosis on the surfaces of stromal cells is far more than that of migrating into the blood vessels. So, our proposal is that there are two sites for thymocytes apoptosis, some die inside the thymus and the others die outside the thymus.

Relationship between glycosylated hemoglobin, blood pressure, serum lipid profiles and body fat distribution in healthy Chinese

Obesity-related metabolic disorders have not been adequately addressed due to a failure to distinguish the importance of general obesity or body fat distribution in relation to atherosclerotic risk factors, especially in the less obese populations. To assess the relationship between general obesity (reflected by BMI, total body fat percentage and total adiposity), body fat distribution (reflected by WHR, default regions and ROIs of DEXA) and atherosclerotic risk factors in the Chinese population, a total of 872 healthy subjects (477 male and 395 female) were enrolled in the study. The results indicated that the android pattern of fat distribution, independent of general obesity, was positively correlated with blood pressure, atherogenic indices, fasting and OGTT 2-h plasma glucose, glycosylated hemoglobin (HbA1c), serum concentration of cholesterol, triglyceride, LDL cholesterol and negatively correlated with HDL cholesterol in both genders. The gender differences in patterns of body fat distribution and atherosclerotic risk factors remained significant after adjustments were made for age, BMI and total adiposity, although diminished after further adjustments for body fat distribution. In conclusion, body fat distribution, rather than general obesity, is more correlated with obesity-related atherosclerotic risk factors and sex-associated differences. ROIs measured by DEXA may be a useful method to evaluate sex-associated changes in body fat distribution and atherosclerotic risk factors in the healthy Chinese population.

Laparoscopic hepatic lobectomy in the porcine model

BACKGROUND

To date, there have been only a few anecdotal reports of laparoscopic hepatectomy, most of which are limited to wedge resections. The aim of this study was to assess the feasibility of laparoscopic hepatic lobectomy in a porcine model.

METHODS

Eight pigs were anesthetized before placement of an abdominal wall lift device and five laparoscopic ports. With the porta hepatis clamped, the left lateral hepatic lobe was divided with an ultrasonic dissector. Small vessels and ducts were clipped, larger vascular structures were transected with staplers, and surface hemorrhage was controlled with an argon beam coagulator. Serum liver enzymes (LFTs) and blood counts were drawn pre- and postoperatively. All animals were killed after 1 week.

RESULTS

Mean +/- SEM operating and clamp times were 131 +/- 8 and 39 +/- 2 min, respectively. There were four intraoperative complications in three animals (three lacerations of the hepatic vein and one tear of the splenic capsule), all of which were controlled at surgery. Mean blood loss was 189 +/- 52 ml, and the mass of the resected specimen was 139 +/- 11 g. There were no postoperative complications or deaths. White blood cell count, hematocrit, and LFTs did not change postoperatively, except for aspartate aminotransferase (AST), which was elevated transiently. There were no bile leaks or intraabdominal abscesses.

CONCLUSIONS

Laparoscopic left hepatic lobectomy was technically feasible in the porcine model using an abdominal wall lift device for exposure. Clinical trials are needed to assess its feasibility and limitations before laparoscopic hepatic lobectomy is deemed safe for human use.

Film-forming polymer-granulated excipients as the matrix materials for controlled release dosage forms

Lactose and dibasic calcium phosphate (DCP) were granulated with various concentrations of film-forming polymers by a stepwise spraying method to prepare a directly compressible matrix excipient. The film-forming polymeric latex of Eudragit RS-30D, Eudragit RL-30D, and Surelease (ethylcellulose) were used in this study as the source of the granulating materials. Better flowability and compressibility were observed for all the granulated particles than the polymer-free granules. Most tablets prepared from the polymer-granulated particles exhibited satisfactory friability of less than 1% except for those prepared from lactose particles granulated with low concentrations of ethylcellulose and from plain lactose granules. Change in tensile strength and tablet thickness were in good agreement with the plasticity of the granulating polymer. Polymer-granulated lactose and DCP provided for controlled release of captopril from matrix tablets. This investigation suggests that conventional excipients can be modified by a simple granulating procedure to provide better physical properties for being used as a matrix material.

Effects of pneumoperitoneum on tumor implantation with decreasing tumor inoculum

INTRODUCTION

The aim of this study was to determine the effect of pneumoperitoneum on the rate of trocar-site implantation with decreasing inoculum of cancer cells.

METHODS

A total of 0.5 ml of GW-39 human colon cancer cell suspensions at 1 percent (approximately 3.2 x 10(5) cells) and at 0.5 percent (approximately 1.6 x 10(5) cells; v/v) were injected into the abdomen of hamsters through a midline incision. Animals in each group were randomized to receive either pneumoperitoneum (1 percent = 33; 0.5 percent = 43) or not (1 percent = 32; 0.5 percent = 39). Gross and microscopic tumor implants were documented seven weeks later at four trocar sites.

RESULTS

In the 1 percent group, pneumoperitoneum significantly increased trocar-site tumor implants from 50 to 71 percent (P < 0.001). Pneumoperitoneum also resulted in the following: 1) more frequent involvement of all four concurrent sites (38 vs. 10 percent; P < 0.02); 2) more frequent palpable tumors (13 vs. 5 percent; P < 0.01); 3) larger tumor mass (2.1 +/- 0.6 g vs. 0.2 +/- 0.1 g; P < 0.02). In the 0.5 percent group, pneumoperitoneum did not significantly increase trocar-site tumor implants, and it did not result in a larger tumor mass. The percent increase in trocar-site implants owing to pneumoperitoneum was influenced by the amount of tumor inoculum (21 percent in the 1 percent group; 10 percent in the 0.5 percent group). The mass of palpable tumor implants after pneumoperitoneum decreased with decreased inoculum: 1 percent = 2.1 +/- 0.6 g; 0.5 percent = 0.3 +/- 0.1 g (P < 0.0001).

CONCLUSIONS

Pneumoperitoneum significantly increased both tumor implantation rate and mass when approximately 3.2 x 10(5) colon cancer cells were injected into the peritoneal cavity. These effects of pneumoperitoneum diminished with one-half as many tumor cells injected in the peritoneal cavity.

Modification of physical characteristics of microcrystalline cellulose by codrying with beta-cyclodextrins

In an attempt to modify the physical properties of microcrystalline cellulose (MCC), the slurry form of this material was codried with beta-cyclodextrin (beta-CD). MCC slurry was blended with beta-CD at concentrations of 10%-50% w/w as a dried mass relative to MCC. The mixtures were then granulated with water and codried at 60 degrees C for 12 h or until a constant weight was reached. Codried granules were pulverized, and the fraction between 61 and 150 microns in size was reserved. The powder and tableting properties of the codried products were compared to those of various grades of MCC and the corresponding components and physical mixtures. The results showed that the products of MCC codried with beta-CD significantly improved the flowability of MCC powder. It is probable that the improved flowability was due to the more rounded shape of particles formed with this codried process, which was confirmed by SEM photographs. Moreover, the compactibility and disintegration properties of tablets produced from the codried products were even better than those using MCC alone, physical mixtures, or various grades of MCC. MCC in a slurry form was more efficient than the existing MCC products in achieving these results, which is postulated to be due to the greater amount of water required and the higher solubility of beta-CD in water promoting the interaction between beta-CD and MCC during granulation. In conclusion, MCC codried with beta-CD provides a useful excipient for direct compression.

The utility of intracorporeal ultrasonography for screening of the bile duct during laparoscopic cholecystectomy

Different strategies and imaging modalities have been used to detect common bile duct (CBD) stones during laparoscopic cholecystectomy. We prospectively compared fluoroscopic intraoperative cholangiography (FIOC) and laparoscopic intracorporcal ultrasonography (LICU) in patients undergoing laparoscopic cholecystcctomy for this purpose. In a consecutive series of 607 laparoscopic cholecystectomics, FIOC was used in the first 407 patients, whereas LICU was preferentially applied to the subsequent 200 patients. When LICU documented CBD stones, the duct was flushed with saline solution after intravenous administration of glucagon, and stone persistence or absence was confirmed by FIOC and/or repeat LICU. In the FIOC group, 10 patients were converted to open cholecystectomy and 16 patients did not undergo FIOC. Among the remaining 381 patients, FIOC was successful in 370 (97%). In the LICU group, two patients were converted and LICU was not performed in 26 patients. In the remaining 172 patients, the cystic duct (CBD) junction and the CBD were visualized in all cases (P <0.05 vs. FIOC). The mean (+/- SEM) times required to complete FIOC and LICU were 15. 1 +/- 0.4 minutes and 5.3 +/- 0.2 minutes, respectively (P <0.0001). Choledocholithiasis was detected in 25 patients (7%) undergoing FIOC and in 22 patients (13%) undergoing LICU (P <0.05). In the LICU group, the mean sizes of the stones cleared by ampullary dilatation and flushing (17 of 22, 77%) and those requiring more invasive methods (5 of 22, 23%) were 1.6 +/- 0.2 mm and 2.7 +/- 0.3 mm, respectively (P <0.01). Sludge seen in the CBD by LICU in 10 patients (6%), which disappeared with flushing in all cases. LICU is accurate, safe, and permits more rapid evaluation of bile duct stones than FIOC during laparoscopic cholecystectomy. LICU may be overly sensitive in detecting small stones and sludge, which are of questionable significance. Stones 2 mm or less can usually be cleared by flushing, whereas larger ones often require invasive techniques for removal.

APC genotype, polyp number, and surgical options in familial adenomatous polyposis

OBJECTIVE

This study was performed to examine the relation between phenotypic expression in patients with familial adenomatous polyposis (FAP) and the site of mutations in the APC (adenomatous polyposis coli) gene. The ability of APC mutations to predict surgical outcome was also investigated.

SUMMARY BACKGROUND DATA

Germline mutations in the APC gene cause FAP and can now be identified by direct mutational analysis. Such an analysis can identify affected persons for close surveillance and spare unaffected persons. Phenotypic expression varies within and among FAP kindreds, but certain mutations have been associated with severe disease. Patients with severe polyposis are frequently offered total proctocolectomy rather than colectomy and ileorectal anastomosis out of concern for increased rectal cancer risk. Mutation analysis may offer a more rational basis for these decisions.

METHODS

The postsurgical courses of 58 patients from 19 FAP kindreds with identified APC gene mutations were reviewed. APC gene mutations were identified by analysis of leukocyte DNA using single-strand conformational analysis and DNA sequencing. FAP severity was defined according to the number of polyps in the colon at the time of resection (< 1000, mild; > 1000, severe). Operations included subtotal colectomy with ileorectal anastomosis (IRA), total proctocolectomy with ileal pouch/anal anastomosis, total proctocolectomy with end ileostomy, and partial colectomy (PC).

RESULTS

Eight different APC mutations were identified. Mutations at codons 1309 and 1328 in exon 15G were associated with a uniformly severe polyposis phenotype. For other mutations, the phenotype was more variable. Patients with APC mutations at codons 1309 and 1328 more commonly underwent proctectomy. Among the 43 patients who initially underwent either IRA or PC, the rectum was later removed in 8. Seven of these patients had a mutation at codon 1309 or 1328. With one exception, all patients with mutations outside the 1309 or 1328 site who initially had IRA have retained their rectum.

CONCLUSIONS

Our data support an association between severe polyposis phenotype and mutations at APC gene codons 1309 and 1328. For patients with these mutations, the prognosis for retaining the rectum is poor.

Production and systemic absorption of toxic byproducts of tissue combustion during laparoscopic surgery

BACKGROUND

Among the potential hazards of laparoscopic surgery using electrocautery is the intraperitoneal release and subsequent absorption of byproducts of tissue combustion. In a porcine model of laparoscopic surgery with smoke production, our aims were to assess (1) the relationship between levels of intraperitoneal carbon monoxide (CO) and systemic carboxyhemoglobin (COHb) and methemoglobin (MetHb), and (2) intraperitoneal concentrations of other noxious gases, including hydrogen cyanide (HCN), acrylonitrile (Acr), and benzene (Bzn).

METHODS

Seven pigs underwent laparoscopic resection of three hepatic wedges using monopolar electrocautery in a CO2 pneumoperitoneum. Sequential arterial samples were drawn to measure [COHb] and [MetHb] perioperatively, while gaseous intraabdominal [CO], [HCN], [Acr], and [Bzn] were assayed intraoperatively.

RESULTS

The mean +/- SEM duration of operation was 90 +/- 2 min, and electrocautery was used for 68 +/- 4 min. Intraabdominal [CO] rose from 0 to 814 +/- 200 ppm (p < 0.01) while [COHb] increased from 2.9 +/- 0.1% to 3.5 +/- 0.1% (p < 0.001). Systemic [MetHb] remained unchanged intra- and postoperatively, ranging from 0.3 to 0.7%. Intraperitoneal [HCN] rose from 0 to 5.7 +/- 0.7 ppm (p < 0.001). [Acr], however, did not change significantly from preoperative values, ranging from 0 to 1.6 +/- 1. 0 ppm, and [Bzn] was undetectable.

CONCLUSIONS

Laparoscopic tissue combustion increases intraabdominal [CO] to "hazardous" levels leading to minimal, yet significant, elevations of [COHb]. Systemic [MetHb] and intraabdominal [HCN], [Acr], and [Bzn] are not elevated to toxic levels. Production of intraperitoneal smoke during laparoscopic electrosurgery therefore may not pose a significant threat to the patient.

Experimental development of an endoscopic approach to neck exploration and parathyroidectomy

BACKGROUND

Recent advances in minimally invasive surgical technology have the potential to lead to new applications outside body cavities. The purpose of the present study was to develop techniques for obtaining endoscopic exposure and access to the pretracheal space in the neck with the goal of performing neck exploration and parathyroidectomy and to evaluate the safety and efficacy of such an approach experimentally.

METHODS

The technique for endoscopic neck exploration was developed in eight adult mongrel dogs and was further evaluated in a survival dog model and in human cadavers. The pretracheal space was accessed by a 2.5 cm midline incision in the lower neck. This space was expanded with a balloon dissector, and exposure was maintained with an external lift device. A 5 or 10/12 mm midline port and two to four lateral 5 mm cervical ports were placed, and dissection was carried out with pediatric endoscopic instruments and an ultrasonic coagulator. Excised parathyroid tissue was verified histologically.

RESULTS

Two-gland parathyroidectomy was successfully completed in five of six dogs; inadequate exposure led to a failed procedure in one animal. Mean operative time was 130 +/- 6 minutes, and there were no operative complications. Serum calcium levels did not change significantly after operation (p = not significant). At autopsy, approximately 20 ml of clear sterile fluid was present in the pretracheal space of every dog. In five human cadavers mean dissection time for attempted four-gland parathyroidectomy was 69 +/- 38 minutes (range, 45 to 135 minutes). Four of four parathyroids were identified and removed in two patients, three of three parathyroids in one patient, three of four parathyroids in one patient, and two of four parathyroids in one patient.

CONCLUSIONS

Parathyroidectomy may be performed safely and reliably in an animal model with minimally invasive techniques that can be applied to parathyroid dissection in human cadavers. These results suggest that an endoscopic approach to neck exploration and parathyroidectomy is potentially feasible and may warrant further study in clinical trials.

Laparoscopic-assisted ileocolic resections in patients with Crohn's disease: are abscesses, phlegmons, or recurrent disease contraindications?

BACKGROUND

Because of the inflammatory nature of Crohn's disease, ileocolic resections are often difficult to perform, especially if an abscess, phlegmon, or recurrent disease at a previous ileocolic anastomosis is present. Our goal was to determine whether the above factors are contraindications to a successful laparoscopic-assisted ileocolic resection.

METHODS

Between 1992 and 1996, 46 laparoscopic-assisted ileocolic resections were attempted. Fourteen patients had an abscess or phlegmon treated with bowel rest before operation (group I), 10 patients had recurrent Crohn's disease at the previous ileocolic anastomosis (group II), and 22 patients had no previous operation and no phlegmon or abscess associated with their disease (group III). These groups were compared with each other and with 70 consecutive open ileocolic resections for Crohn's disease during the same time period (group IV).

RESULTS

Operative blood loss and time were greater in group IV than in groups I, II, and III (245 versus 151, 131, and 195 ml, respectively, and 202 versus 152, 144, and 139 minutes, respectively). Conversion to open procedure occurred in 5 patients (group I, 1 [7%]; group II, 2 [20%]; group III, 2 [9%]). Morbidity was highest in group IV (21% versus 0%, 10%, and 10%, respectively). Only one patient died (group IV, 1%). Length of hospital stay was longest in group IV (7.9 versus 4.8, 3.9, and 4.5 days, respectively).

CONCLUSIONS

The laparoscopic-assisted approach to Crohn's disease is feasible and safe with good outcomes. Co-morbid preoperative findings such as abscess, phlegmon, or recurrent disease at the previous ileocolic anastomosis are not contraindications to a successful laparoscopic-assisted ileocolic resection in select patients.

Implantation of colon cancer at trocar sites is increased by low pressure pneumoperitoneum

BACKGROUND

The purpose of this study was to determine the effect of pneumoperitoneum on the implantation of tumor at trocar sites.

METHODS

GW-39 human colon cancer cell suspension (0.5 ml of 2.5% v/v) was injected into the peritoneal cavity of golden Syrian hamsters through a 1 cm midline incision. Four 5 mm trocars were inserted through the anterior abdominal wall, and the midline incision was then closed. The animals were randomized to receive pneumoperitoneum (n = 62) or no pneumoperitoneum (n = 60) for 10 minutes. Tumor implantations at trocar sites and midline wound incisions were documented grossly and histologically 8 weeks later.

RESULTS

Tumor was identified in 86% (49 of 57) of control animals and 95% (52 of 55) of the experimental group (p = 0.20). Implants increased with pneumoperitoneum at the midline incision from 44% to 71% (p < 0.01) and at trocar sites from 41% to 64% (p < 0.00001).

CONCLUSIONS

Pneumoperitoneum significantly increased tumor implantation at trocar sites and midline incisions.

Respiratory-related facial nerve activity in response to activation of the rostral ventrolateral medulla in the cat

The effects of electrical and chemical activation of the rostral ventrolateral medulla (rVLM) on respiratory-related facial nerve activity were investigated in decerebrated, paralyzed, vagotomized and ventilated cats. The animal was maintained at normocapnia and hypercapnia in hyperoxia. Phrenic and facial nerve activities were simultaneously recorded. Excitation of the rVLM either by electrical current (12.5 to 50 microA, 80 Hz and 0.5 ms pulse duration) or glutamate microinjection (50 mM, 20 to 200 nl) inhibited both phrenic and facial nerve discharges. Although inhibition of the rVLM upon both nerves was attenuated by hypercapnia, this inhibition remained significant during hypercapnia. These results suggest that the rVLM may be involved in the modulation of upper airway patency by controlling respiratory-related facial nerve activity.

Age and sex effects on HbA1c. A study in a healthy Chinese population

OBJECTIVE

To evaluate whether glycohemoglobin levels increase with age in both sexes and to determine the effect of BMI on this increment.

RESEARCH DESIGN AND METHODS

A cross-sectional survey of 4,580 healthy Chinese men and women, aged 20-85 years, was performed. All subjects who did not have identifiable diseases and who were not on medication known to influence glucose tolerance were recruited from participants at the preventive services of the National Cheng-Kung University Hospital. As an indicator of plasma glucose levels, glycohemoglobin was measured. The subjects were classified according to their age and BMI for both men and women, and any relationships with glycohemoglobin levels were evaluated.

RESULTS

In all the BMI groups divided into quartiles, glycohemoglobin levels increased with age. The largest elevation of glycohemoglobin was observed in the 45- to 54-year-old age-group, except in men with a BMI between the lowest and highest quartiles. The group with a BMI above the highest quartile had a higher glycohemoglobin than the group with a BMI below the lowest quartile in men aged < 54 years and women aged 35-64 years. Men had higher average glycohemoglobin levels than women < 55 years of age.

CONCLUSIONS

The age factor itself may cause an elevation in glycohemoglobin independent of other age-related factors in Chinese men and women, and there is a sex difference with a lower average glycohemoglobin level in women before menopause. Furthermore, BMI, but not a family predisposition to diabetes or leisure-time physical activity, affects this age-dependent increase in glycohemoglobin levels.

Primary orbital hemangiopericytoma: a case report

A case of primary orbital hemangiopericytoma is reported in a 31-year-old female presenting with progressive proptosis of the left eye and deteriorating diplopia over a period of 2 years. Orbital computed tomography revealed a superiorly located well-circumscribed extraconal mass. A 32x57x16 mm soft mass that appeared grossly encapsulated was removed intact via anterior orbitotomy. Histopathological examination disclosed it to be a hemangiopericytoma. The clinical importance is its potentially malignant behavior, with a high local recurrence rate in case of incomplete excision. Literature was reviewed.