Broadband scattering properties of articular cartilage zones and their relationship with the heterogenous structure of articular cartilage extracellular matrix.

Significance: Articular cartilage exhibits a zonal architecture, comprising three distinct zones: superficial, middle, and deep. Collagen fibers, being the main solid constituent of articular cartilage, exhibit unique angular and size distribution in articular cartilage zones. There is a gap in knowledge on how the unique properties of collagen fibers across articular cartilage zones affect the scattering properties of the tissue. Aim: This study hypothesizes that the structural properties of articular cartilage zones affect its scattering parameters. We provide scattering coefficient and scattering anisotropy factor of articular cartilage zones in the spectral band of 400 to 1400 nm. We enumerate the differences and similarities of the scattering properties of articular cartilage zones and provide reasoning for these observations. Approach: We utilized collimated transmittance and integrating sphere measurements to estimate the scattering coefficients of bovine articular cartilage zones and bulk tissue. We used the relationship between the scattering coefficients to estimate the scattering anisotropy factor. Polarized light microscopy was applied to estimate the depth-wise angular distribution of collagen fibers in bovine articular cartilage. Results: We report that the Rayleigh scatterers contribution to the scattering coefficients, the intensity of the light scattered by the Rayleigh and Mie scatterers, and the angular distribution of collagen fibers across tissue depth are the key parameters that affect the scattering properties of articular cartilage zones and bulk tissue. Our results indicate that in the short visible region, the superficial and middle zones of articular cartilage affect the scattering properties of the tissue, whereas in the far visible and near-infrared regions, the articular cartilage deep zone determines articular cartilage scattering properties. Conclusion: This study provides scattering properties of articular cartilage zones. Such findings support future research to utilize optical simulation to estimate the penetration depth, depth-origin, and pathlength of light in articular cartilage for optical diagnosis of the tissue.

Teamwork and mental workload in postsurgical pediatric patient handovers: Prospective effect evaluation of an improvement intervention for OR-PICU patient transitions.

Postsurgical handover of pediatric patients from operating rooms (OR) to pediatric intensive care units (PICU) is a critical step. This transition is susceptible to errors and inefficiencies particularly if poor multidisciplinary teamwork occurs. Despite wide adoption of standardized handover interventions, comprehensive investigations into joint effects for patient care and provider outcomes are scarce. We aimed to improve OR-PICU handovers quality and sought to evaluate the intervention with particular attention to patient care effects and provider outcomes. A prospective, before-after-study design with an interrupted-series and a multi-source, mixed-methods evaluation approach was established. Drawing upon a participative plan-do-study-act approach, a standardized, checklist-based handover process was designed and implemented. For effect assessments, we observed OR-PICU handovers on site (pre implementation: n = 31, post: n = 30), respectively, with standardized expert observation and provider self-report tools (n = 111, n = 110). Setting was a tertiary Pediatric University Hospital. Supplementary qualitative, semi-structured interviews were conducted, and a general inductive content analysis approach was used to identify key facilitators and barriers on implementation. Improvement efforts focused on stepwise implementation of (1) standardized handover process and (2) a checklist for multi-professional OR-PICU handover communication. We observed significant increases in team and patient setup (pre: 79.3%, post: 98.6%, p < .01), enhanced team engagement (pre: 50%, post: 81.7%, p < .01), and comprehensive information transfer by the anesthesia sub-team (pre: 78.6%, post: 87.3%, p < .01). Expert-rated teamwork outcomes were consistently higher, yet self-reported teamwork did not change over time. Provider perceived stress and disruptions did not change, mental workload tended to decrease over time (pre: M = 3.2, post: 2.9, p = .08). Comprehensiveness of post-operative patient information reported by PICU physician increased significantly: pre: 65.9%, post: 76.2%, p < .05. After implementation, providers acknowledged the importance of standardized handover practices and associated benefits for facilitation of information transfer and comprehensiveness. Among reported barriers were obstacles during implementation as well as insufficient consideration of professionals' individual workflow after surgery. CONCLUSION:  A multidisciplinary intervention for postsurgical pediatric patient handovers was associated with improved expert-rated teamwork and fewer omissions of key patient information over time. Inconsistent results were obtained for provider-rated mental workload and teamwork outcomes. The findings contribute to a better understanding concerning the interplay of teamwork and provider cognitions in the course of establishing safe patient transitions in pediatric care. WHAT IS KNOWN: • Transfer of critically ill children conveys significant challenges for interprofessional communication and teamwork. Prospective research into interventions for safe and efficient handover practices of OR PICU patient transitions is necessary. • Checklists are assumed to facilitate cognitive load among providers in acute clinical environments. WHAT IS NEW: • A standardized, checklist-based handover intervention was associated with improvements in team set-up and information transfer. Provider outcomes such as mental workload and stress did not change over time. • The combination of teamwork and provider assessments allows a more nuanced understanding of implementation barriers and sustainable effects in course of OR-PICU handover interventions.

Impact of experimental setup parameters on the measurement of articular cartilage optical properties in the visible and short near-infrared spectral bands.

There is increasing research on the potential application of diffuse optical spectroscopy and hyperspectral imaging for characterizing the health of the connective tissues, such as articular cartilage, during joint surgery. These optical techniques facilitate the rapid and objective diagnostic assessment of the tissue, thus providing unprecedented information toward optimal treatment strategy. Adaption of optical techniques for diagnostic assessment of musculoskeletal disorders, including osteoarthritis, requires precise determination of the optical properties of connective tissues such as articular cartilage. As every indirect method of tissue optical properties estimation consists of a measurement step followed by a computational analysis step, there are parameters associated with these steps that could influence the estimated values of the optical properties. In this study, we report the absorption and reduced scattering coefficients of articular cartilage in the spectral band of 400-1400 nm. We assess the impact of the experimental setup parameters, including surrounding medium, sample volume, and scattering anisotropy factor on the reported optical properties. Our results suggest that the absorption coefficient of articular cartilage is sensitive to the variation in the surrounding medium, whereas its reduced scattering coefficient is invariant to the experimental setup parameters.

Epidemiology and injury morphology of traumatic hip dislocations in children and adolescents in Germany: a multi-centre study.

OBJECTIVE: Traumatic hip dislocations are very rare in childhood and adolescence. The aim of this multi-centre study is to analyse the current epidemiology and injury morphology of a large number of traumatic hip dislocations in children. This can provide a better understanding of childhood hip dislocations and contribute to the development of a therapeutic approach in order to prevent long-term impacts. METHODOLOGY: This retrospective, anonymised multi-centre study included patients, aged up to 17 years, with acute traumatic hip dislocations and open growth plates. The patients came from 16 German hospitals. Exclusion criteria included insufficient data, a positive history of hip dysplasia, or an association with syndromal, neurological or connective tissue diseases predisposing to hip dislocation. An analysis was carried out on the patients' anthropometric data and scans (X-ray, MRI, CT), which were collected between 1979 and 2021. Gender, age at the time of dislocation, associated fractures, mechanism of injury, initial treatment including time between dislocation and reduction, method of reduction, treatment algorithm following reduction and all documented complications and concomitant injuries were evaluated. RESULTS: Seventy-six patients met the inclusion criteria. There were two age peaks at 4-8 years and 11-15 years. There was an increased incidence of girls in the under-eight age group, who had mild trauma, and in the group of over-eights there were more boys, who had moderate and severe trauma. Dorsal dislocation occurred in 89.9% of cases. Mono-injuries dominated across all age groups. Concomitant injuries rarely occurred before the age of eight; however, they increased with increasing ossification of the acetabulum and appeared as avulsion injuries in 32% of 11-15-year-olds. Of the 76 patients, 4 underwent a spontaneous, 67 a closed and 5 a primary open reduction. A reduction was performed within 6 h on 84% of the children; however, in around 10% of cases a reduction was not performed until after 24 h. Concomitant injuries needing intervention were identified in 34 children following reduction. Complications included nerve irritation in the form of sensitivity disorders (n = 6) as well as avascular necrosis (AVN) of the femoral head in 15.8% of the patients (n = 12). CONCLUSIONS: Traumatic hip dislocations are rare in childhood and adolescence and have high complication rates. The most severe complication, femoral head necrosis, occurred in 16% of cases. Minor injuries, especially in younger children, are enough to cause a dislocation. Posterior dislocation was more frequent and primarily occurred as a mono-injury; however, concomitant injuries must be considered with increasing age. Children continue to experience delayed reductions. The length of time until reduction, age and the severity of the concomitant injury play a role in the development of femoral head necrosis; however, this topic requires additional investigation.

Intrainstitutional Changes of the Treatment of Supracondylar Humerus Fracture in Children over a Period of 9 Years.

To assess changes in treatment modalities for supracondylar humerus fractures (SCHFs) at a large pediatric university hospital, we analyzed patient data from 2014 to 2022. A total of 233 SCHFs treated surgically at our hospital were included. To evaluate postoperative outcome and quality of life, DASH and EuroQol-5D-Y questionnaires were sent to patients. In addition to a significant fluctuation in fracture severity, we found an increase in training interventions (more surgeries were performed by trainees) and a significant decrease in surgery times after 2016. From 2020, there was a significant shift in the type of surgical method away from closed reduction with elastic stable intramedullary nailing (ESIN) and towards closed reduction and crossed K-wire osteosynthesis (CRK). Surgeries performed in the morning and evening hours increased, while those performed in the afternoon and after midnight decreased. After a mean follow-up of 4 years, there was no difference in elbow function between ESIN and open reduction and K-wires (ORK). Treatment with ESIN was equivalent to ORK in terms of function, at least in the medium-term follow-up. In summary, the combination of shifting treatment from SCHF to daytime hours, increasing trainee participation and using cross K-wire fixation instead of ESIN had no negative impact on surgery times. In our setting, these measures have reduced resource utilization and increased efficiency without compromising patient care.

[Chest Wall Deformities in Children and Adolescents]. / Brustwanddeformitäten bei Kindern und Jugendlichen.

Chest wall deformities as a whole are relatively common in children and adolescents, although they comprise a wide spectrum of entities, some of them rare. Pectus excavatum has the highest prevalence. While some patients are asymptomatic, others suffer from substantial limitations. All symptomatic patients should be offered treatment. Minimally invasive surgical correction is the more effective option of treatment, besides the alternative application of a suction bell. Pectus carinatum and combined manifestations of chest wall deformities can also lead to physiological and psychosocial impairment and require treatment tailored to the individual patient in such cases. Syndromal chest wall deformities, such as Jeune syndrome, comprise a separate group of rare diseases that are associated with considerable, occasionally life-threatening comorbidities. These patients should be cared for in centres with appropriate expertise in an interdisciplinary and multimodal manner. This review discusses the different chest wall deformities encountered in paediatric surgical practice, along with their significance and possible therapeutic approaches.

Precise determination of the optical properties of turbid media using an optimized integrating sphere and advanced Monte Carlo simulations. Part 1: theory.

In this paper, we describe a method used to determine the optical properties, namely, the effective scattering and absorption coefficients, employing an optimized three-dimensional-printed single integrating sphere. The paper consists of two parts, and in Part 1, the theoretical investigation of an optimized measurement and the evaluation routine are presented. Using an analytical and a numerical model for the optical characterization of the integrating sphere, errors caused by the application of a non-ideal sphere (the one with ports or baffles) were investigated. Considering this research, a procedure for the precise determination of the optical properties, based on Monte Carlo simulations of the light distribution within the sample, was developed. In Part 2, we present the experimental validation of this procedure.

Precise determination of the optical properties of turbid media using an optimized integrating sphere and advanced Monte Carlo simulations. Part 2: experiments.

Based on theoretical investigations of the light propagation within an integrating sphere, we developed an accurate method to determine the optical properties of scattering media using an integrating sphere-based setup. The method takes into account the exact sphere geometry as well as the different angular distributions of the reflected and transmitted light from the sample and the calibration standard. We tested our novelties successfully in theory with Monte Carlo simulations and in practice using a 3D printed and professionally coated integrating sphere. As a result, we were able to determine precisely the effective scattering coefficient, µs', and the absorption coefficient, µa, between 400 nm and 1500 nm in a range of µa=1e-3mm-1 to 10mm-1 and µs'=0.2mm-1 to 100mm-1. Usually, the accuracy was around 1% for µs' and around 3% for µa for turbid phantom media with an optical thickness τ=µs'd>1 and a transmittance signal >0.1%.

Team performance during postsurgical patient handovers in paediatric care.

Postsurgical handover of paediatric patients from operating rooms to intensive care units is a critical moment. This process is susceptible to errors and inefficiencies particularly if poor teamwork in this multidisciplinary and ad hoc collaboration occurs. Through combining provider- and observer-rated team performance, we aimed to determine agreement levels on team performance and associations with mental demands, disruptions, and stress. An observational and multisource study of provider and concomitant expert-observer ratings was established. In an Academic Paediatric Hospital, we conducted standardized observations of postsurgical handovers to PICU. We applied established observational and self-reported teamwork tools. Nested fixed and mixed models were established to estimate agreement within teams, between providers' and observer's ratings, as well as for estimations between team performance and mental demands, disruptions, and stress outcomes. Thirty-one postsurgical patient handovers were included with overall 109 ratings of involved providers. Provider-perceived team performance was rated high. Within the receiving sub-team, situation awareness was perceived lower compared to the handoff sub-team [F(df = 1) = 4.41, p = .04]. Inter-provider agreement on handover team performance was low for the overall team yet higher within handover sub-teams. We observed that high level of distractions during the handover was associated with inferior team performance rated by observers (B = - 0.72, 95% CI = - 1.44, - 0.01).Conclusion: We observed substantial disagreements on how involved professionals as well as observers rated teamwork during patient transfers. Investigations into paediatric teamwork and particular team-based handovers should carefully consider if concurrent provider and observer assessments are a valid and reliable way to evaluate teamwork in paediatric care. Common handover language should be established and mandatory before jointly evaluating this process. Our findings advocate also that handovers should be performed under low levels of distractions.What is Known:• Efficient teamwork during transfers of critically ill children is fundamental to quality and safety of handover practice.• Postoperative handovers are often performed by ad hoc teams of caregivers with multiple backgrounds and are prone to suboptimal team performance, communication, and information transfer.What is New:• Our provider and expert evaluations of team performance during OR-PICU handovers showed poor agreement for team performance. Our findings challenge previous results drawing upon single source assessments and inform future studies to carefully consider what approach of team performance assessments is required.• We further demonstrate that high levels of disruptions are associated with poor team performance during patient handovers and that efforts to ensure undisrupted handover practices in clinical care are necessary.

[The treatment of elbow dislocations in children and adolescents : Consensus report of the pediatric trauma section of the German Trauma Society (DGU)]. / Die Behandlung der Ellenbogenluxation im Kindes- und Jugendalter : Konsensusbericht der Sektion Kindertraumatologie der DGU.

Dislocations of the elbow during growth are rare but because of associated fractures a range of therapeutic methods are employed. The postoperative care is even more varied, so the scientific working group of the section for pediatric trauma of the DGU developed the following recommendations for the treatment of elbow dislocations in children and adolescents based on own experience and a review of the literature. Diagnosis is made from radiographs with at least one (preferably lateral) view showing the dislocation. Reduction is considered urgent and should be done as atraumatically as possible with the patient under general anesthesia. After reduction, mobility and stability of the elbow are assessed and associated fractures have to be ruled out by fluoroscopy while the patient is still under anesthesia. Any fractures requiring operative treatment should be addressed at this time. A short-term immobilization should be ordered according to the degree of injury and the stability of any osteosynthesis. The aim should always be to initiate mobilization as soon as possible with immobilization lasting not longer than 3 weeks in any case. Mobilization is initially limited to the activities of daily life at first. 6 weeks after reduction physiotherapy may be initiated as warranted and patients can participate in sports again. An MRI of the elbow may be necessary if there are persistent problems. Even if a measurable loss of range of motion is often recorded, prognosis regarding a good functional outcome is favorable.

Spatial frequency domain imaging using an analytical model for separation of surface and volume scattering.

A method to correct for surface scattering in spatial frequency domain imaging (SFDI) is presented. The use of a modified analytical solution of the radiative transfer equation allows calculation of the reflectance and the phase of a rough semi-infinite geometry so that both spatial frequency domain reflectance and phase can be applied for precise retrieval of the bulk optical properties and the surface scattering. For validation of the method, phantoms with different surface roughness were produced. Contrarily, with the modified theory, it was possible to dramatically reduce systematic errors due to surface scattering. The evaluation of these measurements with the state-of-the-art theory and measuring modality, i.e., using crossed linear polarizers, reveals large errors in the determined optical properties, depending on the surface roughness, of up to ≈100 % . These results were confirmed with SFDI measurements on a phantom that has a structured rough surface.

Parents reported reduced symptoms and improved satisfaction after fundoplication and their perceptions were an important outcome measure.

AIM: Fundoplication is required for children with chronic recurrent gastro-oesophageal reflux disease (GERD). The aim of this study was to report parental perceptions of symptoms and overall satisfaction with the long-term course following fundoplication with special reference to patients with GERD risk factors. METHODS: We studied 34 patients, with a median age of 6.5 ± 4.9 years, who received fundoplication between 2001 and 2005. Clinical information and surgical complications were recorded. Parents were interviewed to evaluate post-operative symptoms, mode of nutrition and satisfaction. RESULTS: The median follow-up time was 7.3 years. Comorbidities were neurological impairment in 15 patients, other gastrointestinal disorders in seven patients and isolated GERD in 12 patients. The parents reported that fundoplication effectively treated initial reflux symptoms in 60% and improved symptoms in 37%. Vomiting and reflux-associated pain were treated most effectively. Pulmonary symptoms often remained unchanged in neurologically impaired children. Redo fundoplication was necessary in seven patients. Only two parents regretted consenting to surgery. CONCLUSION: A high percentage of parents reported improved gastrointestinal reflux-related symptoms and a high level of satisfaction following fundoplication. Parental perceptions of GERD symptoms should be an important outcome measure when assessing the efficacy of antireflux surgery in children in routine clinical follow-up.

Broadband Optical Properties of Milk.

Dairy products play an important role in our daily nutrition. As a turbid scattering medium with different kinds of particles and droplets, each alteration of these components changes the scattering properties of milk. The goal of this work is the determination of the amount of main scattering components, the fat droplets and the casein micelles, by understanding the light propagation in homogenized milk and in raw milk. To provide the absolute impact of these milk components, the geometrical and optical properties such as the size distribution and the refractive index (RI) of the components have to be examined. We determined the reduced scattering coefficient [Formula: see text] and the absorption coefficient [Formula: see text] from integrating sphere measurements. By use of a collimated transmission setup, the scattering coefficient [Formula: see text] was measured. Size measurements were performed to validate the influence of the fat droplet size on the results of the scattering properties; also, the RI of both components was determined by the said coefficients. These results were used to determine the absolute impact of the milk components on the scattering behavior. By fitting Mie theory calculations on scattering spectra [Formula: see text] and [Formula: see text] from different raw milk samples, it was possible to get reliable values for the concentrations of fat and casein and for the size of the fat droplets. By destroying the casein micelles, it was possible to separate the influence of the different scattering components on scattering behavior.

Detecting structural information of scatterers using spatial frequency domain imaging.

We demonstrate optical phantom experiments on the phase function parameter γ using spatial frequency domain imaging. The incorporation of two different types of scattering particles allows for control of the optical phantoms' microscopic scattering properties. By laterally structuring areas with either TiO2 or Al2O3 scattering particles, we were able to obtain almost pure subdiffusive scattering contrast in a single optical phantom. Optical parameter mapping was then achieved using an analytical radiative transfer model revealing the microscopic structural contrast on a macroscopic field of view. As part of our study, we explain several correction and referencing techniques for high spatial frequency analysis and experimentally study the sampling depth of the subdiffusive parameter γ.

Adjustments of global and local hindlimb properties during terrestrial locomotion of the common quail (Coturnix coturnix).

Previous research has resulted in increasing insight into neuro-mechanical control strategies during perturbed locomotion. In contrast, more general analyses on simple model (template)-related parameters during avian terrestrial locomotion are still rare. Quail kinematic data obtained using X-ray videography combined with ground reaction force measurements were used as a basis to investigate how 'global' template and 'local' leg joint parameters in this small, predominantly terrestrial bird change with speed and gait. Globally, quail locomotion approximates a spring-like behavior in all investigated gaits. However, ground reaction forces are more vertically oriented, which may help to balance the trunk. At the joint level, practically all the spring-like work was found to occur in the intertarsal joint (ITJ). From walking to grounded running, the local stiffness of the ITJ decreases similarly to the reduction observed in global leg stiffness. Thus, in gaits without aerial phases the quails may modulate ITJ stiffness to regulate global leg stiffness, and therefore gait changes, to a significant degree. At higher speeds both global leg compression and stiffness are increased (the latter to values not significantly different to those obtained during walking). This enables the animals to shorten contact time and to generate aerial phases (running). However, we did not observe a change in the stiffness in the ITJ with a change of gait from grounded running to running. We hypothesize that a more extended leg at touch-down, controlled by the joint angles in the knee and ITJ, has an important influence in the leg stiffness adjustment process during running.

The effect of fetal tracheal occlusion on lung tissue mechanics and tissue composition.

Fetal tracheal occlusion (TO) is currently used to treat severe cases of congenital diaphragmatic hernia (DH). Clinical and experimental studies suggest an improved postnatal outcome, but lung tissue mechanics after TO have not been studied. We determined the effect of TO on mechanical impedance and lung tissue components in a rabbit model for DH. At 23 days of gestation (term = 31 days) either a sham thoracotomy or a diaphragmatic defect was induced. DH fetuses were randomly assigned to undergo 5 days later TO. Fetuses were delivered by term cesarean section to determine lung to body weight ratio (LBWR), dynamic lung mechanics and lung impedance. Airway resistance (R(aw)), elastance (H(L)), tissue damping (G(L)) and hysteresivity (G(L)/H(L)) were calculated from impedance data. Collagen I and III and elastin were quantified histologically. LBWR was significantly increased by TO compared to DH (P < 0.001) and resistance and compliance of the respiratory system (R(rs), C(rs)) were improved as well. TO resulted in a significant decrease of R(aw) comparable to observations in sham-fetuses, without effect on lung tissue mechanics H(L), G(L) and hysteresivity. This coincides with a significant decrease of collagen I, III and elastin in comparison to DH fetuses. In this first report on lung tissue mechanics in a rabbit model of DH, TO had a substantial effect on tissue morphology yet this was not mirrored in lung mechanics. We conclude that the effect of TO on lung mechanics without in utero reversal of occlusion, is dominated by airway remodeling.

Lung tissue mechanics predict lung hypoplasia in a rabbit model for congenital diaphragmatic hernia.

Several animal models have been proposed to study the pathophysiology of congenital diaphragmatic hernia (CDH). Surgical induction of CDH in fetal rabbits during the pseudoglandular phase has been shown to induce severe pulmonary hypoplasia, but functional studies in this model are scarce. We aimed to measure neonatal pulmonary impedance and related it to the severity of lung hypoplasia. CDH was surgically created in rabbits at 23 days of gestation. Following cesarean delivery at term (31 days) pups were subjected to measurement of total lung capacity (TLC), lung to body weight ratio (LBWR) and lung impedance by forced oscillation technique (FOT). Airway resistance (R(aw)), tissue elastance (H(L)), tissue damping (G(L)), and hysteresivity (eta) (G(L)/H(L)) were calculated from impedance data. Twelve CDH fetuses and 15 controls were available for final analysis. LBWR and TLC were significantly lower in the CDH group compared to gestational and age matched controls (P<0.001). R(aw), H(L), and G(L) were significantly increased in CCDH fetuses. eta and H(L) best reflected lung hypoplasia (LBWR) (r(2) = 0.42 and 0.43; P=0.001), indicating a dominant contribution of lung tissue mechanics to CDH-induced lung hypoplasia. We successfully introduced lung impedance measurement by FOT in neonatal rabbits. Following surgical induction of CDH in the pseudoglandular phase, they have, next to morphological evidence of pulmonary hypoplasia, changes in lung mechanics. Our results for lung tissue mechanics support the concept of delayed pulmonary tissue modeling. We propose to employ functional studies in future experiments when evaluating prenatal interventions aimed at reversing pulmonary hypoplasia.

Laparoscopic fluorescence diagnosis of peritoneal metastases from human hepatoblastoma in nude rats.

AIM: Fluorescence diagnosis is gaining clinical importance for the detection of malignancies in various medical disciplines. The technique relies on the specific metabolic capacity of a lesion to produce a fluorescent compound. It is still unknown whether pediatric solid tumors like hepatoblastoma (HB) are susceptible to this technique as well. METHODS: Human HB (3 x 10(6)) cells were laparoscopically injected (4 mm scope, 18-G needle) underneath the peritoneum of 7 nude rats (mean weight, 198 g). Tumor growth was allowed for 7 weeks. Photosensitization was induced by peritoneal lavage with aminolevulinic acid (3%). After 3 hours, the animals were investigated with white light laparoscopy (WL) and laparoscopic fluorescence diagnosis (LFD), applying the Storz PDD system. Every suspicious lesion was analyzed by spectrometry and harvested for histology. RESULTS: Every tumor seen in WL also demonstrated strong fluorescence during LFD (100%). One micrometastasis, almost invisible in WL, was obviously illuminating in LFD. Spectrometry demonstrated the specific peak of the aminolevulinic acid metabolite protoporphyrin IX at 635 nm and a 6.34-fold increase of the fluorescence intensity. Histology revealed HB in all specimens. CONCLUSION: Human HB can be detected with LFD in a rat model. This finding opens a wide spectrum of experimental and clinical investigations to evaluate the impact of fluorescence diagnosis for pediatric oncology.

Intrapulmonary perfluorooctyl bromide instillation in fetal rabbits.

BACKGROUND: Instilling perfluorooctyl bromide (PFOB) into the fetal lung may lead to alveolar distension. OBJECTIVE: The aim of the study was to evaluate the safety of PFOB instillation into fetal lungs and to determine the radiographic distribution and tissue concentration of PFOB in New Zealand white rabbits. METHODS: Sibling fetuses of pregnant (day 27) New Zealand white rabbits were randomized to intratracheal instillation of 1 mL PFOB with tracheal ligation, instillation without ligation, and unmanipulated controls. The maternal animals were killed directly after instillation, at 3 or 6 hours (n = 10 each). For each study cohort, we determined fetal lung/body weight (FLBW) ratios, the radiographic distribution of PFOB, as well as pulmonary PFOB and water content by tissue distillation. PFOB concentrations in maternal and fetal tissues were assessed by gas chromatography. RESULTS: The relative amount of fetal lung PFOB recovered by fractional distillation was highest in ligated (25%) and lower in unligated lungs (9%). Extrapulmonary PFOB was found in the fetal brain (2.0 +/- 0.7 ppm), but not in any other fetal or maternal tissues. Mean FLBW ratios were highest in ligated fetuses, followed by unligated fetuses and controls. PFOB partially displaced fetal lung water. PFOB was visible in the lungs of all treated fetuses. Fetal survival between manipulated and unmanipulated fetuses did not differ. CONCLUSIONS: After prenatal intrapulmonary instillation, some PFOB remains in the lung, even if the trachea is not ligated, and may exert distending pressure on the alveoli.

Postnatal lung mechanics, lung composition, and surfactant synthesis after tracheal occlusion vs prenatal intrapulmonary instillation of perfluorocarbon in fetal rabbits.

BACKGROUND/PURPOSE: Fetal tracheal occlusion (TO) accelerates lung growth but decreases surfactant production. We have previously shown that instillation of perfluorooctylbromide (PFOB) into fetal rabbit lungs leads to lung growth similar to TO. This study compares neonatal lung mechanics and surfactant production after prenatal intrapulmonary PFOB instillation vs TO. METHODS: In each of 18 pregnant rabbits on gestational day 27, sets of 4 fetuses underwent either (1) intrapulmonary instillation of 1 mL PFOB, (2) TO, (3) instillation of 1 mL 0.9% NaCl (saline), and (4) hysteroamniotomy without fetal manipulation (control). Fetuses were born by cesarean delivery after 48 hours. Fetuses of 12 rabbits were mechanically ventilated for 15 minutes to evaluate lung compliance and airway resistance. Pulmonary surfactant protein B (SP-B) was quantified by immunohistochemistry in fetuses of the remaining 6 rabbits. RESULTS: Compliance was decreased in the TO group after cesarean delivery (0.33 +/- 0.13 mL/cm H2O) compared with PFOB (0.59 +/- 0.12 mL/cm H2O), saline (0.50 +/- 0.12 mL/cm H2O), and control (0.52 +/- 0.10 mL/cm H2O) fetuses. Mean fetal lung to body weight ratio was higher in TO and PFOB fetuses compared with saline and control. Higher water content and lower numbers of surfactant protein B-positive cells were found in the TO-treated fetuses. CONCLUSIONS: Both prenatal intrapulmonary instillation of PFOB and TO accelerate lung growth, but TO is associated with decreased postnatal lung compliance, possibly influenced by decreased surfactant production and increased fluid retention. Conversely, instillation of PFOB preserved lung compliance and surfactant synthesis.