Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels.

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

Trial protocol: a clustered, randomised, longitudinal, type 2 translational trial of alcohol consumption and alcohol-related harm among adolescents in Australia.

BACKGROUND: This cluster randomised control trial is designed to evaluate whether the Communities That Care intervention (CTC) is effective in reducing the proportion of secondary school age adolescents who use alcohol before the Australian legal purchasing age of 18 years. Secondary outcomes are other substance use and antisocial behaviours. Long term economic benefits of reduced alcohol use by adolescents for the community will also be assessed. METHODS: Fourteen communities and 14 other non-contiguous communities will be matched on socioeconomic status (SES), location, and size. One of each pair will be randomly allocated to the intervention in three Australian states (Victoria, Queensland and Western Australia). A longitudinal survey will recruit grade 8 and 10 students (M = 15 years old, N = 3500) in 2017 and conduct follow-up surveys in 2019 and 2021 (M = 19 years old). Municipal youth populations will also be monitored for trends in alcohol-harms using hospital and police administrative data. DISCUSSION: Community-led interventions that systematically and strategically implement evidence-based programs have been shown to be effective in producing population-level behaviour change, including reduced alcohol and drug use. We expect that the study will be associated with significant effects on alcohol use amongst adolescents because interventions adopted within communities will be based on evidence-based practices and target specific problems identified from surveys conducted within each community. TRIAL REGISTRATION: The trial was retrospectively registered in September, 2017 ( ACTRN12616001276448 ), as communities were selected prior to trial registration; however, participants were recruited after registration. Findings will be disseminated in peer-review journals and community fora.

Fenestrated Endovascular Aortic Aneurysm Repair as a First Line Treatment Option to Treat Short Necked, Juxtarenal, and Suprarenal Aneurysms.

OBJECTIVES: The outcomes of fenestrated endovascular aneurysm repair (FEVAR) as a first line strategy is reported. METHODS: All consecutive patients treated with FEVAR for short neck, juxtarenal, or suprarenal aortic aneurysms under the guidance of the senior author within the period January 2010 to December 2014 were included. Data were collected from a prospectively maintained database. Analyzed outcomes included technical success, defined by successful stent graft implantation with patent stented target vessels and no Type I/III endoleak, operative mortality and morbidity, target vessel patency, endoleak, re-intervention, and death. Survival, target vessel stent patency, and re-intervention during follow up were calculated by Kaplan-Meier analysis. RESULTS: A total of 281 patients (245 male, mean age 72.1 ± 7.7 years) were treated. The mean aneurysm diameter was 60.2 ± 9.3 mm and median proximal neck length 2 mm (range 0-10 mm). Technical success was 96.8% (272/281). Technical failure included one intra-operative death due to embolization and cardiac arrest, one open conversion due to iliac rupture, and seven target vessel complications. The thirty day mortality was 0.7% (2/281). Mean follow up was 21 ± 15.9 months. Estimated survival at 1 and 3 years was 94.7% ± 1.6% and 84.6% ± 3.0%, respectively. Estimated freedom from re-intervention at 1 and 3 years was 96.1% ± 1.4%, and 90% ± 2.7%. Estimated target vessel stent patency at 1 and 3 years was 98.6% ± 0.5%, and 98.1% ± 0.6%, respectively. Mean aneurysm sac diameter decreased from 60.2 ± 9.3 mm pre-operatively to 53.2 ± 12.8 mm (p < .001). CONCLUSIONS: FEVAR as a first line strategy was associated with high technical success and a low operative mortality rate. Efficacy and durability in the mid-term appear very good, with significant regression of aneurysm sac diameter, high target vessel patency, and acceptable rate of re-intervention.

[Results of endovascular repair of TAAA in the first 50  patients]. / Bericht über die ersten 50 endovaskulären thorako-abdominellen Behandlungen mit Seitenarmprothesen.

BACKGROUND: Developments with fenestrated and branched stent grafts have opened the way to treat complex aortic aneurysms involving the visceral arteries. First reports on endovascular treatment of thoracoabdominal aneurysms have demonstrated the feasibility of the technique. METHODS: A literature review and results of first 50  patients treated with a custom-made Zenith device with fixed branches are presented. Most of the patients were refused open surgery mainly for the extent of the disease combined with co-morbidity, which included in most patients a combination of several risk factors. Mean aneurysm size was 71 mm and extent of the aneurysm was type  I (n = 9), type  II (n = 13), type  III (n = 19), and type  IV (n = 9), respectively. RESULTS: Primary and primary assisted technical successes in our series were 88 % (44 / 50) and 92 % (46 / 50), respectively. One patient died on day  1 from an intraoperative aneurysm rupture. In two patients a renal artery was lost, one due to rupture and one due to malpositioning of the bridging stent graft. In a fourth patient, a celiac artery could not be catheterised and was lost. Finally, in two more patients, catheterisation of in total three renal arteries proved impossible. This was solved by a retrograde approach for two renal arteries via laparotomy in one patient, and a spleno-renal bypass in the other patient. Thirty-day mortality was 8 %. Estimated survival at 6  months, 1  year, and 2  years was 91.2 %, 79.8 %, and 69.7 %, respectively. Freedom of reintervention of all kinds at 1 and 2  years was 81.9 % and 73.7 %, respectively. CONCLUSION: Results of fully endovascular repair of thoracoabdominal aneurysms in a high-risk cohort are promising. A learning curve should be expected. Although longer term results need to be awaited, it is likely that endovascular repair of thoracoabdominal aneurysms will become a preferential treatment option for many patients in the future.

First experience with the new repositionable C3 excluder stent-graft.

AIM: The Gore Excluder device is a modern third generation device that performs well. Nevertheless, the proximal deployment was not as accurate and controlled as with some other modern devices. Therefore a new deployment system was developed. This system allows to reconstrain the graft after initial deployment, with the purpose to reposition the graft for both level or orientation. METHODS: The new system was used in 25 patients with an infrarenal abdominal aortic aneurysm. In 72% of cases the system was used to achieve a better proximal position or to facilitate catheterization of the contralateral limb. Surprisingly, the option to orientate the graft was used most. RESULTS: The new deployment system worked well, and all grafts were easily repositioned to the intended final position. Additional cuffs were not required in any of the patients. Surgical mortality was nil. All patients left the hospital in good condition. There were no type I endoleaks at completion angiography neither at first computed tomography scanning. CONCLUSION: With the new deployment system it is possible to reposition the Excluder to achieve optimal fixation and sealing. A global registry has been set into place to report real life results including longer term performance of the graft.

Early enteral feeding compared with parenteral nutrition after oesophageal or oesophagogastric resection and reconstruction.

After resective and reconstructive surgery in the gastrointestinal tract, oral feeding is traditionally avoided in order to minimize strain to the anastomoses and to reduce the inherent risks of the postoperatively impaired gastrointestinal motility. However, studies have given evidence that the small bowel recovers its ability to absorb nutrients almost immediately following surgery, even in the absence of peristalsis, and that early enteral feeding would preserve both the integrity of gut mucosa and its immunological function. The aim of this study was to investigate the impact of early enteral feeding on the postoperative course following oesophagectomy or oesophagogastrectomy, and reconstruction. Between May 1999 and November 2002, forty-four consecutive patients (thirty-eight males and six females; mean age 62, range 30-82) with oesophageal carcinoma (stages I-III), who had undergone radical resection and reconstruction, entered this study (early enteral feeding group; EEF). A historical group of forty-four patients (thirty-seven males and seven females; mean age 64, range 41-79; stages I-III) resected between January 1997 and March 1999 served as control (parenteral feeding group; PF). The duration of both postoperative stay in the Intensive Care Unit (ICU) and the total hospital stay, perioperative complications and the overall mortality were compared. Early enteral feeding was administered over the jejunal line of a Dobhoff tube. It started 6 h postoperatively at a rate of 10 ml/h for 6 h with stepwise increase until total enteral nutrition was achieved on day 6. In the controls oral enteral feeding was begun on day 7. If compared to the PF group, EEF patients recovered faster considering the duration of both stay in the ICU and in the hospital. There was a significant difference in the interval until the first bowel movements. No difference in overall 30 d mortality was identified. A poor nutritional status was a significant prognostic factor for an increased mortality. Early enteral feeding significantly reduces the duration of ICU treatment and total hospital stay in patients who undergo oesophagectomy or oesophagogastrectomy for oesophageal carcinoma. The mortality rate is not affected.

Intrapleural instillation of rituximab for the treatment of malignant pleural effusions in NHL.

A patient with CD20(+) leukaemic lymphoplasmacytic Non-Hodgkin's lymphoma (NHL) presented with bilateral malignant pleural effusions. Systemic chemotherapy, repeated percutaneous drainage and bilateral continous chest tube drainage were unable to control the effusions. Rituximab was instilled in a dose-escalating manner via the chest tubes into both pleural spaces, within two weeks the effusions resolved, and the patient has stayed free of symptoms for eight months ongoing. Rituximab may be a promising novel treatment option for malignant effusions in CD20(+) NHL.

Invasion of blood vessels as significant prognostic factor in radically resected T1-3N0M0 non-small-cell lung cancer.

OBJECTIVES: Radical resection is the therapy of choice in non-small-cell lung cancer (NSCLC). However, even in early stages (T1N0, T2N0) up to 35% of patients will experience recurrence. The aim of this retrospective study was to evaluate the prognostic influence of lymph vessel or blood vessel invasion in N0 patients. METHODS: A total of 72 patients (male, 49; female, 23; median age 59; range 40-72) with NSCLC entered the study. The stages were T1-3N0 (T1, 25; T2, 41; T3, 6). Thirteen pneumonectomies and 59 lobectomies or bilobectomies with systematic lymphadenectomy and R0 resection were performed. Histologically, 24 adenocarcinomas, 31 squamous cell carcinomas and 14 subtypes of large cell carcinoma were found. In 22 cases microscopic invasion of the lymphatic vessels and in 11 invasions of blood vessels were found. Six patients showed invasion of either structure. RESULTS: The patients were followed up for at least 5 years or until death. During the follow-up period 27 patients died (21 because of recurrence and 6 because of diagnosis not related to NSCLC). The 5 years overall survival amounted to 62.5%. In cases with invasion of the blood vessels the survival rate was 23.5%, in cases without invasion 74.5% (P< or = 0.01), whereas lymph vessel invasion had no significant impact on survival. Multivariate analysis covering T stages, histological subtypes, location of the tumor, grading, age, sex, and invasion of the lymphatic or the blood vessels showed invasion of the blood vessels as the only factor with significant prognostic impact in the study population. CONCLUSIONS: In resectable N0 patients with NSCLC the microscopic invasion of blood vessels should be considered as an additional prognostic parameter.

Acid-related diseases following retrosternal stomach interposition.

BACKGROUND/AIMS: Esophagectomy and reconstruction with retrosternal stomach interposition implies bilateral truncal vagotomy, which supposedly causes gastric functional impairment. METHODOLOGY: Esophagectomy and reconstruction with retrosternal stomach interposition was performed on 15 men (mean age: 58.4 years) and 3 women (mean age: 43.6 years). The stomach was pedicled on the right gastric and right gastroepiploic artery without performing pyloroplasty. The cervical side-to-end anastomosis was sutured manually. The functional results were assessed 2-4 years postoperatively, by determining 24-hour qualitative intragastric pH-measurement, fluoroscopical gastric emptying studies, fasting gastrin levels, and endoscopy with biopsy studies. RESULTS: Endoscopy and biopsy confirmed esophagitis in 12 patients, gastritis in 15 and a gastric ulcer in 1 case. Fluoroscopic examination documented a normal passage of contrast medium in 17, slight impairment in 1 case treated by balloon dilatation of the pylorus. Qualitative intragastric pH-measurement revealed a total pH < 3 in 22.5-98.05% of measuring events (mean: 74.31%) within 24 hours, in 18 cases. Only 4 patients had pH < 3 in less than 50%. Fasting gastrin levels (normal range: 25-110 mU/L) varied from 48.78 mU/L-168.20 (mean: 85.23 mU/L). Only 3 patients had levels > 110 mU/L (maximum: 168.20 mU/L). CONCLUSIONS: Acid-related diseases may also occur after truncal vagotomy and retrosternal stomach interposition. Routine follow-up endoscopy and biopsy studies should be done to prevent inflammatory complications and maintain the patient's quality of life.

Indications for surgery in tracheobronchial ruptures.

OBJECTIVE: Ruptures of the tracheobronchial tree present a life-threatening situation. Nevertheless, therapy is still controversial. Though conservative treatment by antibiotics and intubation with the cuff inflated distal to the tear is favored by some authors, surgical repair is unavoidable in many cases. METHODS: We present a series of 31 patients (mean age 43.6 years, range 8--72 years) with iatrogenous or post-traumatic tracheobronchial ruptures treated since 1975. Fifteen ruptures were longitudinal tears of the trachea, not extending lower than a distance of 3 cm from the bifurcation, 11 involved the bifurcation and/or the main bronchi. The total length of the longitudinal tears ranged from 2 to 12 cm, five were transverse near complete abruptions of the trachea or main bronchi. Involvement of the full thickness of the wall with free view into the pleural space or to the esophageal wall was present in 29 cases. Twenty-nine out of the 31 patients underwent surgical repair and two were treated conservatively. The length and depth of the lesion, the degree of subcutaneous emphysema, pneumothorax and/or pneumomediastinum as well as clinical signs suggesting incipient mediastinitis were considered when making the decision for surgery. RESULTS: Twenty-five out of the 29 patients experienced an uneventful recovery. Four patients died of sepsis unrelated to the tracheobronchial trauma. One of the two patients who underwent conservative therapy also recovered uneventfully. The other one died because of multi-organ failure due to underlying myocardial infarction. CONCLUSIONS: Conveniently localized short lacerations, especially if they do not involve the whole thickness of the tracheal wall, can be treated with antibiotics and intubation with the cuff inflated distal to the tear, avoiding high intra-bronchial pressures also after eventual extubation. In all other cases surgical repair is to be preferred.

Loss of heterozygosity on chromosome arm 11q in lung carcinoids.

Neuroendocrine lung tumors such as typical carcinoid, atypical carcinoid, small-cell lung carcinoma, and large-cell neuroendocrine carcinoma represent a variable group with different biologic characteristics and unclear genetical relationships. We investigated the pattern of allelic loss on chromosome arm 11q in 20 sporadic carcinoid tumors of the lung using 10 microsatellite markers. Loss of heterozygosity was found in 13 of 20 tumors. In 5 of 9 typical carcinoids, 3 distinct regions of allelic loss were identified: 11q13.1 (D11S1883), 11q14.3-11q21 (D11S906), and 11q25 (D11S910). Atypical carcinoids showed loss of heterozygosity at 4 different regions: the first, most proximal region at 11q13 between markers PYGM and D11S937; the second at 11q14.3-11q21 (D11S906); and the third and fourth defined by markers D11S939 (11q23.2-23.3) and D11S910 (11q25). However, the region 11q13 harboring the MEN1 gene was more frequently affected in atypical carcinoids (7 of 11) than in typical carcinoids (2 of 9). The high rate of allelic losses within chromosomal region 11q13 in atypical carcinoids emphasizes the importance of this region for tumor development. We also recognized that more aggressive atypical carcinoids defined by high mitotic counts, vascular invasion, and/or organ metastasis are combined with increased allelic losses. HUM PATHOL 32:333-338.

Effective-index increase, form birefringence and transition losses in UV-side-illuminated photosensitive fibers.

We present a simple variational method for the analysis of UV-side-illuminated single-mode fibers. We use a shiftable, two-dimensional elliptical Gaussian function as a field trial for the fundamental-mode. By this method, the actual UV-induced peak refractive-index increase can be quantitatively related to the measured effective-index increase. The asymmetry of the UV-induced refractive-index profile due to the absorption of the writing UV light causes both form birefringence and transition losses between UV-illuminated and non-illuminated fiber sections. These characteristics are easily calculated from the results of the variational method. We show that UV-illumination of the fiber from two opposite sides reduces both the form birefringence and the transition losses.

Four-year experience with pleural abrasion using a rotating brush during video-assisted thoracoscopy.

BACKGROUND: Due to the high recurrence rate in primary spontaneous pneumothorax (PSP), surgical therapy is currently a well-accepted method of treating this condition. There is no general agreement about the best time for surgical intervention (i.e., after the first or second episode) or the optimal surgical approach,--i.e., tube thoracocenteses, thoracotomy, or video-assisted thoracoscopy (VATS) with or without pleurectomy or pleurodesis. The aim of this study was to verify the efficacy of VATS and mechanical brush pleurodesis using a rotating electrical brush system. METHODS: We treated 47 patients with PSP between June 1993 and June 1997. Follow-up ranged from 20 to 56 months. There were 38 male and nine female patients with a mean age of 26 years. Emergency thoracocenteses due to tension pneumothorax became necessary in three patients. All patients were treated by VATS and mechanical brush pleurodesis. Wedge resection was done if bullae or blebs were present (68.1%). RESULTS: Operating time was 20-60 min (mean, 35). There were no intraoperative complications and no conversions to conventional surgery. In the first few postoperative days, postoperative pain was controlled with nonsteroidal antirheumatic drugs and additional morphines. Drainage time was 3-7 days (mean, 4). Hospitalization time was 4-8 days (mean, 5). The recurrence rate was 2.1% (one patient). No postoperative bleeding or wound infection occurred in any of our patients. CONCLUSIONS: VATS combined with mechanical brush pleurodesis using the electrical brush system is a highly effective and safe treatment for patients with recurrent primary spontaneous pneumothorax.

Does hyperbaric oxygen enhance the effect of photodynamic therapy in patients with advanced esophageal carcinoma? A clinical pilot study.

BACKGROUND AND STUDY AIMS: Experimental studies have shown that the cytotoxicity of porphyrins and related substances is mediated mainly by singlet oxygen and that hypoxic cells are less affected by porphyrins and light. In a clinical pilot study we assessed the use of photodynamic therapy (PDT) under hyperbaric oxygen (HBO), compared with PDT under normobaric conditions, in patients with advanced esophageal carcinoma. PATIENTS AND METHODS: After diagnostic work-up and staging, photosensitization in all patients was carried out using hematoporphyrine derivate (HpD) (2 mg/kg bodyweight 48 hours prior to PDT). We then applied light at 630 nm (KTP-Nd: YAG laser with DYE box) at dose of 300 J/cm, delivered by a fiber with a radial light-diffusing cylinder (length 1 cm), inserted through the biopsy channel of the endoscope. Of the patients, 14 (12 with stage III cancers, and two with stage IV cancers) were treated by PDT alone, and 17 patients (15 with stage III cancers, and two with stage IV cancers) received PDT under HBO at a level of 2 absolute atmospheric pressures (ATA). Transcutaneous PO2 levels of 500-750 mm Hg under HBO, compared with transcutaneous PO2 levels of 60-75 mm Hg under normobaric conditions, were measured. RESULTS: Improvements regarding dysphagia and stenosis diameter were obtained in both treatment arms with no significant differences (P = 0.36 and 0.14, respectively). The tumor length also decreased in both groups and showed a significant difference in favour of the PDT/ HBO group (P = 0.002). Kaplan-Meier statistics showed median overall survival for the PDT group and the PDT/HBO group as 7.0 and 12 months respectively. The 12-month survival rate was 28.6% for the PDT group and 41.2% for the PDT/HBO group. Logrank test showed a difference in survival in favor of the PDT/HBO group (P = 0.059). No major treatment-related complication occurred, and the 30-day mortality rate was 0%. CONCLUSIONS: Combined PDT/HBO represents a new approach in the treatment of esophageal cancer which, in this pilot study, appears to have enhanced the efficiency of PDT.

Modal field deformation and transition losses in UV side-written optical fibers.

The asymmetry of the UV-induced refractive-index profile in photosensitive optical fibers causes a deformation of the modal fields, resulting in transition losses between UV-exposed and unexposed fiber sections up to 0.1 dB for UV-induced index changes of the order of

Radiotherapy for invasive thymoma and thymic carcinoma. Clinicopathological review.

PURPOSE: This study reports clinicopathological features and outcome of thymic tumors. Twenty-seven patients with invasive thymoma and 6 patients with thymic carcinoma who had received radiotherapy either primary or postoperatively were analyzed retrospectively. PATIENTS AND METHODS: All 33 patients were irradiated with a mean dose of 50 Gy after complete resection (16 patients), partial resection (9 patients) or biopsy (8 patients). Staging was done according to the Masaoka classification; there were 12 Stage II, 12 Stage III and 9 Stage IV patients. RESULTS: In patients with invasive thymoma Stage II to IV (median follow-up 54.4 months) Kaplan-Meier estimates of overall survival (OS), disease-specific (DSS) and disease-free survival (DFS) at 5 years were 63.7% (95% confidence interval [CI], 42 to 84%), 88.3% (CI, 75 to 100%) and 77.4% (CI, 58 to 95%), respectively. Among the prognostic factors tested, such as age, myasthenia gravis, completeness of surgery and histologic subclassification, total radiation dose, and Masaoka Stage, the latter was the only significant predictor of improved survival (p = 0.04). Considering local control, radiation dose was a significant prognostic factor (p = 0.0006). In patients with thymic carcinoma (median follow-up 43.4 months) 5-year DSS, and DFS were 22.2% (CI, 0 to 60%) and 16.7% (CI, 0 to 46%), respectively. Thymoma as compared to thymic carcinoma had a statistically significant better DSS (p = 0.007) and DFS (p = 0.0007). CONCLUSION: Postoperative radiotherapy with sufficient doses plays an important role as adjuvant treatment in complete or incomplete resected invasive Stage II to III thymoma. In unresectable thymoma Stage III to IV as well as in thymic carcinoma a multimodality approach should be considered to improve survival.

Self-expandable coated stent after intraluminal treatment of esophageal cancer: a risky procedure?

BACKGROUND: Stenting is a well established palliative treatment for stenotic malignant disease of the esophagus. Because of its merely mechanical potential other tumoricidal techniques are often done before stenting. METHODS: We did esophageal stenting in 11 patients (9 men and 2 women) using a self-expanding coated stent system. Three tumors were localized in the proximal, four in the middle, and four in the distal third of the esophagus. In 9 patients tumors were locally or functional nonresectable, 1 patient refused an operation, and 1 had a recurrence after esophagojejunostomy. One patient had had pretreatment by repetitive dilatation and local hyperthermia, 9 had had photodynamic therapy followed by endoluminal iridium 192 high-dose rate brachyradiotherapy, and 1 patient was admitted with esophagotracheal fistula. The interval between the last endoluminal treatment and stent insertion was between 3 and 29 days (mean, 11 days). RESULTS: In 7 patients (63.7%) no complications were observed. Four patients (36.3%) died of major complications within 1 week. Postmortem examination confirmed that the pressure of the fully expanding stent to the esophageal wall caused the rupture. CONCLUSION: The use of self-expanding coated stents in pretreated esophageal tumors is associated with a high risk of perforation due to pressure of the indwelling tube in a less resistant esophageal wall.

Is aggressive surgery in pleural empyema justified?

OBJECTIVE: High risk and a long hospitalization time are often quoted as negative aspects of aggressive surgery in pleural empyema. We did a retrospective analysis evaluating outcome and duration of hospitalization in patients treated according to an aggressive schedule. METHODS: Since 1989 we have treated 101 patients with pleural empyema (72 males, 29 females; mean age 50.3 years, range 11-91 years; 77 metapneumonic empyema, 24 empyema following trauma or abdominal surgery). Sixty-nine patients had had unsuccessful conservative pre-treatment (antibiotics, thorcozentses, drainage/irrigation, VATS). Thirty-one were critically ill patients. In eight cases a seropurulent stage of empyema was present, 17 patients had fibrinous membranes, 30 an organizing stage with and 46 without well identifiable dissection plane. Eighty-five patients proceeded to thoracotomy. Pulmonary abscesses or indurative pneumonia necessitated wedge-resection, lobectomy, or pneumonectomy in 29 cases. In the presence of gross necroses or callosities not amenable to decortication primary open-window thoracostomy (n = 22) was carried out. In six cases a secondary open-window thoracostomy was carried out because of persisting putrid secretion and sepsis persisting after decortication or after drainage. The thoracostomy was closed when clean granulative tissue developed. Sixteen patients underwent only drainage and irrigation because of an early stage or because of a general condition not permitting thoracotomy. RESULTS: Three patients died due to severe sepsis not responding to treatment, one had fatal bleeding from a duodenal ulcer (mortality rate 3.9%). The others were able to resume their preoperative activities. The median duration of hospitalization was 14 days (mean 21.1 days; SEM 1.7 days). CONCLUSION: Aggressive surgery for pleural empyema beyond the seropurulent stage ensures rapid relief from sepsis at a low mortality rate even in very ill patients.

Modes of UV-written planar waveguides.

The UV-induced refractive-index increase in photosensitive planar waveguides is modeled by an exponential profile. Closed-form field solutions are given and dispersion curves are calculated for TE and TM modes. Modes in air-covered waveguides can be less sensitive to the UV-written profile than modes in buried waveguides.