Management and outcomes of primary coloduodenal fistulas.

PURPOSE: Primary coloduodenal fistula (CDF) is a rare entity. We review our experience with the management and outcomes of CDF. METHODS: This is a retrospective review from 1975 to 2005 of patients with primary CDF. Patients were followed through clinic visits and mail correspondence with a mean (±SE) follow-up of 56 ± 14 months. RESULTS: Twenty-two patients were diagnosed at a mean age of 54 ± 3 years with primary CDF: benign (n = 14) or malignant (n = 8). Benign CDF were due to Crohn's disease (n = 9) or peptic ulcer disease (n = 5); malignant CDF was primarily due to colon cancer (n = 7) plus 1 patient with lymphoma. Indications for operative intervention included intractable symptoms (n = 15), gastrointestinal bleeding (n = 14), and to rule out malignancy (n = 8). Complete resection of malignant CDF with negative margins was achieved in half of patients after en bloc resection. Palliative bypass was performed in those patients with unresectable disease. Thirteen patients with benign CDF had resection of the fistula-2 of these patients required a duodenal bypass. There were no perioperative deaths, and the morbidity rate was 38%. Median survival for patients with malignant CDF was 20 months (range 1-150 months). Two patients with malignant CDF had >5-year survival. All patients with benign CDF who underwent fistula resection had resolution of fistula-related symptoms with one recurrence. CONCLUSION: Benign CDF is amenable to operative therapy with resolution of symptoms and a low recurrence rate. Complete resection of malignant CDF can impart survival benefit.

Use of a microporous polytetrafluoroethylene catheter balloon to treat refractory esophageal stricture: a novel technique for delivery of mitomycin C.

PURPOSE: Endoluminal application of mitomycin C shows promise as a nonsurgical approach to treating recalcitrant stricture but requires precise delivery to prevent mitomycin-mediated injury to adjacent normal mucosa. We describe a novel technique that uses a microporous polytetrafluoroethylene catheter balloon to endoluminally deliver mitomycin C to the target tissue while minimizing nontarget drug application. MATERIALS AND METHODS: A newborn infant with proximal tracheoesophageal fistula and distal atresia underwent an uncomplicated repair. However, he developed recurrent esophageal stricture resistant to multiple attempts at pneumatic dilations. An image-guided endoluminal radiologic approach that uses microporous polytetrafluoroethylene catheter balloon was developed to precisely deliver mitomycin C to the mucosal lining of the stricture post-dilation. RESULTS: After uncomplicated pneumatic dilation under fluoroscopic guidance, we used a microporous balloon catheter to endoluminally deliver mitomycin C topically to the mucosa at the level of stricture. Three weeks post procedure, repeat esophagram showed resolution of the stricture with unobstructed flow of contrast material to the stomach. The patient had no observable side effects from mitomycin C application. CONCLUSION: Image-guided therapies based on balloon dilation and drug-eluting microporous balloon techniques offer a safe, precise, and comprehensive approach to the treatment of recalcitrant esophageal strictures.

Liver transplantation for pulmonary vascular complications of pediatric end-stage liver disease.

PURPOSE: Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are poorly understood pulmonary complications of end-stage liver disease (ESLD). We present a case series of children with HPS and PPH. METHODS: After institutional review board approval, query of our medical database identified children 0 to 18 years of age with ESLD diagnosed with HPS or PPH. Data were collected via chart review. RESULTS: We identified 7 children with either HPS (n = 5) or PPH (n = 2). Patients with HPS presented with progressive dyspnea over a mean of 7 months (range, 4-12 months) at a mean of 13 years (range, 5-17 years) of age. Pulmonary shunting by albumin perfusion scan averaged 41% (range, 20%-66%) with an initial mean resting SpO(2) of 88% (range, 84%-94%) and mean SpO(2) during exertion of 79% (range, 60%-89%). Four patients required supplemental O(2) and, upon United Network for Organ Sharing (UNOS) appeal, received pediatric model for ESLD (or Child-Pugh) score exceptions, enabling them to undergo orthotopic liver transplant (OLT) within 1-2 months. The fifth patient was initially rejected by the UNOS regional review board, but 6 months of worsening hypoxemia led to OLT 2 months after successful UNOS appeal. All patients with HPS undergoing OLT experienced complete resolution of hypoxemia within 8 months. Both children with PPH were treated with intravenous epoprostenol, which lowered or stabilized mean pulmonary artery pressure and bridged them to OLT within 7 months of listing. Overall, there were no pulmonary complications; however, 1 patient with PPH expired shortly after OLT. The remaining patients are alive at a median follow-up of 27 months (range, 6-96 months). CONCLUSION: Hepatopulmonary syndrome and PPH are uncommon complications of ESLD in children. Epoprostenol can bridge PPH patients to OLT. OLT leads to rapid resolution of HPS and PPH and currently represents the only successful treatment for these children.

Outcome of adrenocortical tumors in children.

PURPOSE: This study reviews adrenocortical tumors in children to determine factors that significantly affect outcome. METHODS: An institutional review board-approved retrospective review from 1976 to 2005 identified 23 patients younger than 19 years old with histologic confirmation of adrenocortical carcinoma (ACC) and adenomas. RESULTS: The mean age of the 23 children was 9.0 +/- 1.6 years; girls predominated (female-to-male ratio = 1.9:1) as did cancers (ACC 16, adenoma 7); tumor hormone production (74%); and advanced stage for disease (66%). All malignancies were more than 2.5 cm. Adrenalectomy, including en bloc resection of adjacent structures (35%) achieved grossly negative margins in 70% of patients. Three patients received chemotherapy or chemoradiation as primary treatment without surgery. There was no perioperative mortality; morbidity was 10% (pneumothorax, acute renal failure, chylous ascites, and thrombocytosis). Surgical cure without adjuvant therapy was achieved for all adenomas and ACC stages I and II. For ACC stage III and IV, median survival was 21 months, 5-year survival was 0%. All advanced-staged ACC received adjuvant therapy. Surgically negative margins conferred a survival advantage. CONCLUSIONS: Children, especially females with ACC present with large advanced-staged tumors. Surgically negative margins with or without en bloc resection improves survival. The high percentage of children with functioning tumors suggests earlier detection is possible.

Pediatric endoscopic injuries: incidence, management, and outcomes.

BACKGROUND: Endoscopy has assumed a significant role in the management of gastrointestinal disorders. However, endoscopic-related injuries are poorly reported. METHODS: Review of our surgical database (1980-2006) identified all patients age 18 years or younger with an endoscopic-related injury managed at our institution. RESULTS: A total of 3269 colonoscopies were performed; there were 3 iatrogenic perforations (incidence, 0.09%). All were managed operatively: 2 underwent fecal diversion, and 1 was repaired primarily. There was 1 postoperative complication (internal hernia) and no deaths related to colonoscopic perforation. Nine thousand three hundred eight esophagogastroduodenoscopy (EGD) procedures were performed, resulting in 6 iatrogenic injuries (0.06%): bleeding (2), perforation (2), and mucosal tears (2) (0.02% each). All EGD-related injuries occurred in the esophagus except for 1 duodenal perforation which was managed operatively by primary repair. Both patients with bleeding complications underwent repeat endoscopy and cautery with satisfactory results. The other 3 patients were managed conservatively without complication. Three hundred eighty-nine endoscopic retrograde cholangiopancreatogram procedures were performed with 2 iatrogenic injuries (0.5%): 1 bleed and 1 perforation (0.25% each). Both were managed conservatively without complication. CONCLUSION: Endoscopic injuries are uncommon. Colonoscopic perforations require prompt surgical intervention. Esophagogastroduodenoscopy- and endoscopic retrograde cholangiopancreatogram-related injuries are amenable to conservative therapy in clinically stable patients devoid of peritonitis.

Minimally invasive repair for pectus excavatum in adults.

BACKGROUND: The purpose of this study is to review the minimally invasive pectus excavatum repair in adults to determine the safety and effectiveness. METHODS: An Institutional Review Board approved chart review identified patients 17 years or older who underwent minimally invasive pectus excavatum repair (MIPER) between January 1999 and January 2004. RESULTS: Nineteen patients underwent MIPER. Indications for surgery were reduced exercise tolerance (13), dyspnea on exertion (17), improve self-perception (10), and chest pain (6). There were no intraoperative complications or conversions to open repair. Twelve patients (63%) required one strut and seven patients (37%) required two struts. Postoperative complications included self-resolving asymptomatic pneumothorax in six patients and pneumonia in one. Pain at six weeks postoperatively was mild to none in most patients and all had no pain at three months postoperatively except one patient with strut displacement. Two patients required removal of one of two struts due to displacement. The mean postoperative pectus index was significantly lower than preoperative value: 2.5 versus 4.6, p = 0.002. Among six patients with strut removal at two years postoperatively, two patients had mild recurrence of their deformity. CONCLUSIONS: Minimally invasive pectus excavatum repair can be performed safely in adults. This approach is technically more challenging in adults with one-third of the patients requiring two struts for optimal repair. The risk of strut displacement is higher than in the pediatric population. The long-term effectiveness and durability of this procedure in adults is still unknown.

Long-term outcome of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique.

BACKGROUND: Repair of complex incisional hernias poses a major challenge. AIM: The aim of this study was to review the outcomes of the modified Rives-Stoppa repair of complex incisional hernias using a synthetic prosthesis. METHODS: We reviewed patients undergoing a modified Rives-Stoppa repair of complex incisional hernias from 1990 to 2003. Patients were followed through clinic visits and mailed questionnaires. Follow-up data were complete in all patients (mean 70 months, range 24-177 months), and 87% of patients completed a mailed questionnaire. Primary outcome included mortality, morbidity, and hernia recurrence. Secondary outcome measures were duration of hospital stay, long-term abdominal wall pain, and self-reported patient satisfaction. RESULTS: Altogether, 254 patients underwent a modified Rives-Stoppa repair. Among them, 60% had a significant co-morbidity, and 30% had one or more previously failed hernia repairs. Mortality was zero, and overall morbidity was 13% (wound infection 4%, prosthetic infection 3%, seroma/hematoma 4%). The overall hernia recurrence rate was 5%, including explantation of mesh because of infection. Wound/prosthetic infection was predictive for hernia recurrence (31% vs. 4%, p = 0.003). Among the respondents, 89% reported overall satisfaction with their repair. CONCLUSION: The Rives-Stoppa repair of complex incisional hernias using synthetic prosthetic materials is safe with a low recurrence rate (5%) and high patient satisfaction. Postoperative wound infection is a risk factor for hernia recurrence.

Retroperitoneal sarcomas in children: outcomes from an institution.

BACKGROUND: Retroperitoneal sarcomas are uncommon in children and tend to present as large tumors with advanced locoregional involvement of abdominopelvic structures. Surgical control of these tumors remains to be a management challenge. We reviewed our institutional experience with retroperitoneal sarcomas in children. MATERIALS AND METHODS: In a retrospective review of charts dating between 1975 and 2005, we identified patients younger than 18 years who were diagnosed with a histologically confirmed retroperitoneal sarcoma. Patients were followed prospectively through clinic visits and mail correspondence. Standard statistical methods were used for comparative, risk, and survival analyses. RESULTS: Twenty-one children with a mean age at presentation of 9 +/- 1 years were identified. There were more boys than girls (male/female ratio = 1.6). The most common presentations were abdominal mass/distention (76%) and pain (62%). The mean tumor size was 14.2 +/- 1.4 cm, with locoregional involvement in 62% of the patients. The common histologic types were rhabdomyosarcoma (33%) and fibrosarcoma (33%). Seventy-six percent of the patients underwent primary or secondary resection, 71% received neoadjuvant and/or adjuvant chemotherapy therapy, and 38% received radiation therapy. Complete resection was achieved in 48% of the patients, including 3 who required inferior vena cava resection and reconstruction. The 5-year disease-specific survival rates for patients who underwent complete resection and those who underwent incomplete resection were 90% and 36% (P = .018), respectively. For all patients, the mean survival time was 103 +/- 16 months and the 5-year disease-specific survival rate was 62%. Survival was significantly better for patients with low-grade sarcomas than for those with high-grade sarcomas (90% vs 36%, P = .008). Among those who underwent an initial complete resection, 50% had a recurrence at a mean time of 88 +/- 52 months (range = 3-261 months). The 30-day postoperative mortality and morbidity rates were 0% and 24%, respectively; in addition, 14% of the patients experienced long-term complications. CONCLUSIONS: Resection of retroperitoneal sarcomas can be performed safely with minimal morbidity and mortality. Complete resection and low histologic grade are associated with significantly better disease-specific survival.

Outcomes of primary liver cancer in children: an appraisal of experience.

INTRODUCTION: Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the most common primary liver cancers in children. Recent advances in management of pediatric liver cancer have improved disease-specific survival (DSS). This is a review of our experience with childhood liver malignancy over the past 3 decades. MATERIALS AND METHODS: A retrospective chart review from 1975 to 2005 identified patients who were 18 years old or younger with a histologically confirmed diagnosis of primary liver cancer. Patients were staged according to the Children's Cancer Group and Pediatric Oncology Group (CCG/POG) system. Patients were followed up prospectively through clinic visits and mail correspondence. Standard statistical methods were used for comparison, risk, and survival analyses. RESULTS: Fifty-two patients were confirmed to have primary liver cancers, where 24 (46%) patients had HB, 22 (42%) had HCC, 3 (6%) had sarcomas, and 3 (6%) had other histologies. Mean ages at presentation for HB and HCC were 3.2 and 13.1 years old, respectively. The most common presentations were abdominal mass (67%) and pain (40%). Most patients underwent major liver resection (n = 45, 87%), including: lobectomy (n = 25, 48%), and trisegmentectomy (n = 11, 21%). Three patients underwent liver transplantation (n = 3, 6%) for advanced local disease. Forty-five (87%) received primary or neoadjuvant and/or adjuvant chemotherapy. Patients had the following CCG/POG stages: I (n = 31, 60%), II (n = 6, 11.5%), III (n = 9, 17%), and IV (n = 6, 11.5%). Complete gross resection (stage I and II) was achieved in 37 (71%) patients. The perioperative mortality and morbidity rates were 0% and 29%, respectively. Patients with complete resection had significantly better 5-year DSS and median survival compared with incomplete gross resection: 62% vs 9% and 216 vs 18 months, P < .001. Patients treated during the period 1995-2005 had better 5-year DSS and median survival compared with those treated during 1975-1994: 68% vs 32% and 117 vs 27 months, P = .032. All 3 patients who underwent transplantation for conventionally unresectable disease are alive without disease recurrence (follow-up period, 1-15 years). CONCLUSION: Complete resection of the pediatric primary liver tumors remains the cornerstone of treatment to achieve cure. Major liver resection can be performed with minimal perioperative mortality and morbidity. Patients with HB appeared to have better survival compared with patients with HCC, and there was significant improvement in the DSS of children treated in the recent decade. Liver transplantation in conjunction with chemotherapy may have an increasing role in the management of locally advanced primary liver cancers.

Pancreatic pseudocyst in children: the impact of management strategies on outcome.

INTRODUCTION: Persistent pancreatic pseudocysts (PPs) are rare in childhood and management tends to be individualized. The purpose of this review is to determine the impact of different management strategies and to analyze their effects on patient outcomes. METHODS: An institutional review board-approved retrospective chart review was performed on children younger than 18 years who had PP diagnosed between January 1976 and December 2003. RESULTS: There were 24 patients, 13 male and 11 female, with a mean age 10.7 years (range, 2-17 years). The mean PP size was 5.8 cm (range, 1.7-20 cm). Posttraumatic pseudocysts were identified in 11 children. The etiologies of 13 nontraumatic PP were idiopathic (6), familial pancreatitis (4), drug-induced (1), cholelithiasis (1), and bifid duct (1). All patients were symptomatic at diagnosis. Resolution of pseudocysts without operative intervention occurred in 7 (29%) of 24 patients. The mean time to operation for the remaining 17 children (71%) was 13.1 weeks (range, 6-36 weeks), with indications for intervention including persistent/recurrent abdominal pain (17), failure to thrive (9), infected PP (1), and ruptured PP (1). Surgical therapies for 13 of 17 patients consisted of cystogastrostomy (8), cystojejunostomy (2), longitudinal pancreaticojejunostomy (2), and Frey's procedure (1). Four patients underwent pancreatic sphincterotomy and stenting, 2 of whom also had image-guided pseudocyst drainage. The intervention-related mortality and morbidity rates were 0% and 11%, respectively, for children undergoing surgical therapies. The morbidities included pancreatic leak (1) and wound infection (1). Etiology of the PP had a significant influence on the need for intervention (traumatic, 45%; nontraumatic, 92%; P = .02); however, patient age, size, and location of the PP had no significant effect. All 24 patients continued to do well at mean follow-up of 73.3 months (range, 6 weeks-25 years). One patient with idiopathic pancreatitis has since developed insulin-dependent diabetes. All 4 patients with familial pancreatitis had their chronic pain improved without long-term narcotic therapy. CONCLUSION: The treatment of PPs in children is dependent on etiology, where pseudocysts from nontraumatic etiologies are more likely to require and benefit from surgical interventions, whereas pseudocysts from traumatic etiology are more amenable to conservative management. For children with persistent symptoms or interval complication, surgical therapy is safe and effective.

Pheochromocytoma and paraganglioma in children: a review of medical and surgical management at a tertiary care center.

OBJECTIVE: The aim of this study was to review our institutional experience managing pheochromocytomas and paragangliomas in children. METHODS: A retrospective chart review of the Mayo Clinic database from 1975 to 2005 identified 30 patients < 18 years of age with histologically confirmed pheochromocytoma or paraganglioma. RESULTS: There were 12 patients with pheochromocytomas and 18 with paragangliomas. The most common presenting symptoms were hypertension (64%), palpitation (53%), headache (47%), and mass-related effects (30%). Nine patients (30%) had a genetic mutation or documented family history of pheochromocytoma or paraganglioma. Fourteen patients (47%) had malignant disease, whereas 16 (53%) had benign disease. Logistic analysis showed that statistically significant risk factors for malignancy were (1) paraganglioma, (2) apparently sporadic, as opposed to familial, pheochromocytoma or paraganglioma, and (3) tumor size of > 6 cm. Surgical resection was performed for 28 patients (93%), with perioperative mortality and major morbidity rates of 0% and 10%, respectively. Resection achieved symptomatic relief for 25 patients (83%). All patients with benign disease appeared cured after resection. For patients with malignant disease, the 5- and 10-year disease-specific survival rates were 78% and 31%, respectively, and the mean survival time was 157 +/- 32 months. CONCLUSIONS: The incidence of malignant pheochromocytoma/paraganglioma was high in children (47%), particularly those with apparently sporadic disease, paraganglioma, and tumor diameters of > 6 cm. Patients with a known genetic mutation or familial pheochromocytoma/paraganglioma were more likely to achieve resection with negative microscopic margins and had improved disease-specific mortality rates. Surgical resection remains the treatment of choice for pheochromocytoma and paraganglioma.

Bilateral staged versus bilateral simultaneous thoracotomy in the pediatric population.

AIM: The aim of the study was to evaluate the safety and outcomes of simultaneous bilateral thoracotomy in pediatric patients compared with traditional bilateral staged thoracotomy. METHODS: This is a retrospective review of 30 consecutive patients 18 years or younger undergoing either bilateral staged or bilateral simultaneous thoracotomy between March 1994 and July 2004. Follow-up (mean, 47 months) was available for all patients. RESULTS: Thirty patients (17 boys, 13 girls; average age, 12 years) underwent bilateral staged or bilateral simultaneous thoracotomy. Eighteen patients underwent staged thoracotomy, 9 patients underwent simultaneous thoracotomy, and 3 patients underwent both procedures. Diagnosis included sarcoma (n = 21), Wilms tumor (n = 4), indeterminate pulmonary nodules (n = 3), and germ cell tumor (n = 2). When we compared outcomes for patients undergoing simultaneous versus staged bilateral thoracotomy, mean hospital stay (5.2 vs 10.6 days; P < .002), intensive care unit stay (1 vs 2 nights; P < .0001), days with tube thoracostomy (4 vs 8 days; P < .0005), and time to initiation of adjuvant chemotherapy (13 vs 30 days; P < .05) were all significantly less for patients undergoing bilateral simultaneous thoracotomy. In addition, postoperative complications were less frequent in patients undergoing simultaneous versus staged thoracotomy (0 vs 3 events; P = .25). CONCLUSIONS: In selected patients, bilateral simultaneous thoracotomy is safe and may lessen morbidity and hospital stay while avoiding delay in initiation of adjuvant chemotherapy.

Sensitivity and utility of parathyroid scintigraphy in patients with primary versus secondary and tertiary hyperparathyroidism.

INTRODUCTION: Parathyroid scintigraphy (PS) may be used to localize hyperactive parathyroid glands preoperatively. Performance of PS in the setting of secondary and tertiary hyperparathyroidism (HPT) is not well quantified. The performance of PS in secondary/tertiary HPT versus primary HPT may reflect physiologic as well as radiopharmaceutical kinetic differences between multigland hyperplasia versus adenoma. The aim of this study was to review the performance of PS in secondary/tertiary HPT with a comparison to that for primary HPT. Moreover, we evaluated (1) the sensitivity of PS in detecting enlarged glands, and (2) PS detectability as a function of gland weight. METHODS: We performed a retrospective review of the Mayo Clinic database from 2000 to 2004. We identified 40 patients with secondary or tertiary HPT as well as a matched control group of 40 patients with primary HPT who had had preoperative PS and underwent parathyroid surgery. RESULTS: Parathyroid scintigraphy correctly localized all enlarged glands in 88% of patients in the primary HPT group. PS correctly identified both the number and locations of all hyperplastic glands in only 28% of the secondary/tertiary HPT patients. PS failed to identify one enlarged gland in 23% of the patients and two or more enlarged glands in 40% of the patients. PS correctly detects the largest gland in 88% of the patients with secondary and tertiary HPT. The mean gland weight detectable by PS was 612 +/- 120 mg for primary HPT. In secondary/tertiary HPT, glands detected by PS had a mean weight of 950 +/- 109 mg, whereas the mean weight was 276 +/- 34 mg for undetected glands (P < 0.002). CONCLUSIONS: Parathyroid scintigraphy is a sensitive study for localizing parathyroid glands preoperatively in primary HPT patients. Its sensitivity is low in secondary and tertiary HPT patients. Thus PS has limited value as a preoperative localization study in secondary/tertiary HPT patients.

Surgical and chemotherapy treatment outcomes of goblet cell carcinoid: a tertiary cancer center experience.

BACKGROUND: Goblet cell carcinoid (GCC) is a rare malignant tumor with distinct histological and clinical features. Our goals were to review the surgical and chemotherapy outcomes of patients with GCC. METHODS: We performed a retrospective review of the Mayo Clinic database from 1984 to 2004 with a prospective follow-up of 57 patients with GCC. RESULTS: The age at diagnosis (mean +/- SE) was 55 +/- 13 years. The most common presentations were right lower quadrant pain mimicking appendicitis (70%) and right lower quadrant or pelvic mass (25%). Only patients with T4 lesions had positive mesenteric nodes, with a frequency of 28%. Fifty percent of female patients had metastasis to the ovaries. The disease-specific 5-year survivals for stages I, II, III, and IV were 100%, 76%, 22%, and 14%, respectively; the overall mean survival was 47 +/- 3 months. All stage I patients had simple appendectomy. The overall 5-year survival rates for patients with combined stages II to IV who underwent appendectomy versus right hemicolectomy were 43% and 34%, respectively (P = .604). The corresponding survival rates for adjuvant chemotherapy versus no chemotherapy were 32% and 27%, respectively (P = .151). CONCLUSIONS: The prognosis for patients with GCC tumors correlates well with the American Joint Committee on Cancer stage at initial presentation. Appendectomy alone seems adequate for stage I disease. For staging purposes, right hemicolectomy is appropriate for T4 tumors or stage II to III disease provided that it can be performed with minimal risk. Surgical debulking is a consideration but is controversial. Adjuvant chemotherapy with 5-fluorouracil and leucovorin regimen is minimally effective against GCC.

Noninvasive monitoring of hemodynamic stress using quantitative near-infrared frequency-domain photon migration spectroscopy.

Hemorrhagic hypovolemia and inotropic agent administration were used to manipulate cardiac output (CO) and oxygen delivery in rabbits to investigate the correlation between noninvasive frequency domain photon migration (FDPM) spectroscopy and invasive hemodynamic monitoring parameters. Frequency-domain photon migration provides quantitative measurements of light absorption and reduced scattering (mu(a) and mu(s)(prime prime or minute), respectively) in tissue. Wavelength dependent mu(a) values were used to calculate in vivo tissue concentration of deoxyhemoglobin [Hb], oxyhemoglobin [HbO(2)], total hemoglobin [TotHb], and water [H(2)O] as well as mixed arterial-venous oxygen saturation (S(t)O(2)) in tissue. FDPM-derived physiologic properties were correlated with invasive measurements of CO and mean pulmonary artery pressure (mPAP), FDPM-derived [TotHb] and S(t) O(2) correlated significantly with hemorrhaged volume (HV), mPAP, and CO. Correlation coefficients for [TotHb] vs HV, mPAP, and CO were -0.77, 0.86, and 0.70, respectively. Correlation coefficients of S(t)O( 2) vs HV, mPAP, and CO were -0.71, 0.55, and 0.61, respectively. Dobutamine induced changes resulted in correlation coefficients between FDPM-derived and invasively measured physiologic parameters that are comparable to those induced by hypovolemia. FDPM spectroscopy is sensitive to changes in mPAP and CO of as little as 15%. These results suggest that FDPM spectroscopy may be used in clinical settings to noninvasively monitor central hemodynamic parameters and to directly assess oxygenation of tissues.

Critical aspects for the reliable headspace analysis of plants cultivated in vitro.

Various factors controlling the recoveries of volatile organic compounds in vitro headspace analysis of tomato plants (Lycopersicon esculentum Mill. 'Moneymaker'), sampled using solid phase micro-extraction, were evaluated and optimised. The variations in composition of the headspaces were determined as a function of time, and following in vitro wounding of the plant.

Automated dynamic sampling system for the on-line monitoring of biogenic emissions from living organisms.

An automated system for continuous on-line monitoring of biogenic emissions is presented. The system is designed in such a way that volatiles, emitted as reaction to biotic or abiotic stress, can be unequivocally elucidated. Two identical sampling units, named target and reference bulb, are therefore incorporated into the system and consecutively analyzed in monitoring experiments. A number of precautions were considered during these experiments to avoid the application of unwanted stress onto both organisms. Firstly, the system is constructed in such a way that both bulbs are continuously flushed, i.e. before, during and after analysis, with high purity air to avoid any accumulation of emitted volatiles. Moreover, the air is pre-humidified by bubbling it through water to sustain the biological samples for longer periods in the in vitro environment. Sorptive enrichment on polydimethylsiloxane (PDMS) was used to trap the headspace volatiles. The hydrophobic nature of this material permitted easy removal of trapped moisture by direct flushing of the sampling cartridge with dry air before desorption. The system was used to monitor the emissions from in vitro mechanically wounded ivy (Hedera helix) and of in vitro grown tomato plants (Lycopersicon esculentum Mill.) upon cotton leafworm (Spodoptera littoralis) feeding. Differences in light and dark floral emissions of jasmine (Jasminum polyanthum) were also studied.

Monitoring of isothiocyanates emanating from Arabidopsis thaliana upon paraquat spraying.

Arabidopsis thaliana plants were sprayed with the superoxide-generating herbicide paraquat. The headspace of sprayed plants was characterized by a number of compounds, which were absent in the headspace of untreated plants. They were identified as isothiocyanates (ITCs) with 4-methylthiobutyl isothiocyanate as main compound. After identification, a GC-system, based on PDMS sorption, was used to continuously monitor the ITC emissions. The specificity of isothiocyanate emission was also determined by subjecting the Arabidopsis thaliana plants to in vitro mechanical wounding. Again, 4-methylthiobutyl isothiocyanate was the main component, but the emission profile was completely different since the compound was emitted immediately, i.e., during wounding itself.

Automated capillary gas chromatographic system to monitor ethylene emitted from biological materials.

An automated capillary gas chromatographic system to measure ethylene emitted from biological materials is presented. The system consists of an on-line sampling device, a thermodesorption preconcentration apparatus and a capillary gas chromatograph with a flame ionization detection system. The limit of detection achievable on the GC system alone is 5 pg ethylene. The use of the strong Carboxen 1000 adsorbent at a sampling temperature as low as -50 degrees C allows sampling of volumes up to a few liters. Ethylene concentrations at low ppt levels can be accurately and reproducibly determined.

Polarization Effects in Optical Coherence Tomography of Various Biological Tissues.

Polarization sensitive optical coherence tomography (PS-OCT) was used to obtain spatially resolved ex vivo images of polarization changes in skeletal muscle, bone, skin and brain. Through coherent detection of two orthogonal polarization states of the signal formed by interference of light reflected from the biological sample and a mirror in the reference arm of a Michelson interferometer, the depth resolved change in polarization was measured. Inasmuch as any fibrous structure will influence the polarization of light, PS-OCT is a potentially powerful technique investigating tissue structural properties. In addition, the effects of single polarization state detection on OCT image formation is demonstrated.