bluuebunny/crossref_metadata_2025 huggingface dataset:
Proton MR spectroscopy in quantitative in vivo determination of fat content in human liver steatosis
Authors: Longo Renata , Pollesello Piero , Ricci Claudio , Masutti Flora , Kvam Bjarne J. , Bercich Luisa , Croce Lory S. , Grigolato Piergiovanni , Paoletti Sergio , De Bernard Benedetto , Tiribelli Claudio , Dalla Palma Ludovico
Published: March 2007

To demonstrate that the lipid volume fraction In liver steatosis can be accurately estimated with in vivo hydrogen‐1 magnetic resonance (MR) spectroscopy, the authors developed a calibration procedure based on in vitro MR spectroscopy of lipid extracts from steatotlc liver specimens. The lipid volume fractions determined with the calibration procedure were compared with the results of histomorphometry and with calibrated computed tomographic (CT) data. The volume fraction of fat determined with MR spectroscopy was in good agreement with the CT results, whereas histomorphometry underestimated the amount of hepatic fat. The results indicate that determination of the fat volume fraction in steatotic liver can be achieved noninvasively with MR spectroscopy.
T2‐weighted MR imaging of the chest: Comparison of electrocardiograph‐triggered conventional and turbo spin‐echo and nontriggered turbo spin‐echo sequences
Authors: Haddad John L. , Rofsky Neil M. , Ambrosino Michael M. , Naidich David P. , Weinreb Jeffrey C.
Published: March 2007

In 22 patients with a diverse range of thoracic abnormalities, T2‐weighted magnetic resonance (MR) images of the chest were obtained with electrocardiograph (ECG)‐triggered turbo spin‐echo (TSE), ECG‐triggered conventional spin‐echo (CSE), and nontriggered TSE sequences, and the images were compared. A 5‐point rating scale was used by three radiologists experienced in MR imaging of the chest to Independently evaluate the images for (a) freedom from ghosting, (b) clarity of heart wall and cardiac chambers, (c) clarity of mediastinal structures, (d) conspicuity of abnormalities, and (e) overall image quality. Evaluations were analyzed with statistical methods. For freedom from ghosting, clarity of heart wall and cardiac chambers, clarity of mediastinal structures, and overall image quality, the ECG‐triggered TSE images were rated higher than the TSE images, which. In turn, were rated higher than the ECG‐triggered CSE images at the P=.05 level of significance. No significant differences were seen between the pulse sequences in the conspicuity of abnormalities, although some differences were observed in individual cases. Our results suggest that ECG‐triggered TSE imaging provides improved, time‐efficient T2‐weighted images of the chest.
Oral superparamagnetic contrast agent (ferumoxsil): Tolerance and efficacy in MR imaging of gynecologic diseases
Authors: Haldemann Heusler Regina C. , Wight Edward , Marincek Borut
Published: March 2007

The purpose of this study was to determine the tolerance and the efficacy of the oral contrast agent ferumoxsil in the assessment of gynecologic diseases. Twenty patients underwent MR imaging at 1.5 T. T1‐weighted spin‐echo (SE) and T2‐weighted fast SE images were obtained before and after ingestion of 600900 mL of the Superparamagnetic negative contrast agent ferumoxsil. No side effects were observed. No statistically significant increase in artifact generation was present in the postcontrast images. The efficacy in bowel marking was significant for the small bowel (P = 0.0001) and the cecum (P < 0.01), but not significant in all sequences for the sigmoid. In the postcontrast images, delineation of the uterus, the right‐sided adnexa, the lymph nodes, and the pathologic lesions was significantly better (P < .01), but not all sequences showed an improvement in delineation of the other pelvic organs. After administration of ferumoxsil, the level of confidence in diagnosis was significantly higher (P = .0001), but no change in diagnosis was made from the preto the postcontrast images. We found the oral contrast agent ferumoxsil to be well tolerated and effective in marking the bowel and in delineating the normal organs as well as the pathologic lesions on pelvic MR images.
Selection of MR images for automated segmentation
Authors: McClain Kevin J. , Zhu Yunqiang , Hazle John D.
Published: March 2007

MR images show a large range of contrast for various tissues in the body and are ideal for multispectral segmentation. Typically, only two MR images (dualecho series) are used for segmentation: however, other images are often available. We evaluated MR images from 40 patients to determine the optimal type and number of images required for segmentation of tissues associated with brain tumors (normal brain, edema, necrosis. and active tumor). Pattern recognition methods indicated that three MR images from the same slice location were adequate for segmentation. M defined by feature selection and feature extraction measures based on training fields. This result was also confirmed by visually examining segmented images for all 40 patients. The work demonstrates that by using existing imagelrtatistid analysis techniques (feature selection and feature extraction). one can systematically determine the optimal type and number of MR images for tissue segmentation.
First‐pass contrast‐enhanced inversion recovery and driven equilibrium fast gre imaging studies: Detection of acute myocardial ischemia
Authors: Saeed Maythern , Wendland Michael F. , Lauerrna Kirsi , Sakurna Hajirne , Chew Wil , Derugin Nikita , Higgins Charles B.
Published: March 2007

The purpose of this study was (1) to monitor the dynamic effects Of T1 ‐enhancing and magnetic SUSCCPtibility contrast material on normal canine myocardium using inversion recovery (IR)‐ and driven equilibrium @E)‐prepared fast gradient‐recalled echo (GRE) sequences and (2) to determine the relative value of T1‐enhancing and magnetic eusceptibflity contrast material in detecting regions of ischemia in the same animal. Normal dogs (n = 5) and dogs with acute occlusion of the left anterior descending (LAD] coronary artery [n = 11) were studied using a 1.5‐T NIR imager. ECG‐gated fast IR‐prepared GRE images were acquired using TI/TR/TE of 700/7.0/2.9 msec and a flip angle of 7°. Fast DE‐prepared GRE images were obtained using a flip angle of 12° and a DE delay /TR/TE of 60/10.2/4.2 msec. Sequential images were acquired to monitor transit of 0.06 mmol/kg gadodiamide injection and 0.2 and 0.4 mmol/kg sprodiamide injection. On slice‐nonselective IR fast GRE images. gadodiamide caused signiflcant enhancement of the normal myocardium and the left ventricular (LV) chamber blood. In dogs with LAD occlusion, the ischemic region was defined as an area of low signal intensity (SI). On DE‐prepared GRE sequences, administration of sprodiamide resulted in a substantial decrease in signal from normal myocardium and LV chamber blood in normal dogs. In animals subjected to LAD occlusion, this contrast medium produced a transient decrease in SI from normal myocardium [P <.06) and no signiflcant change in SI from ischemic myocardium. IR‐ and DE‐prepared taet GRE imaging can be used to monitor the transit of Tl‐enhancing and magnetic susceptibility contrast material in the heart. respectively. Cardiac image quality was much better when slice‐nonselective IR‐prepared fast GRE sequences were used rather than DE‐prepared fast GRE.
Unsupervised Measurement of Brain Tumor Volume on MR Images
Authors: Velthuizen Robert P. , Clarke Laurence P. , Phuphanich Surasak , Hall Lawrence O. , Bensaid Amine M. , Arrington John A. , Greenberg Harvey M. , Silbiger Martin L.
Published: March 2007

We examined unsupervised methods of segmentation of MR images of the brain for measuring tumor volume in response to treatment. Two clustering methods were used: fuzzy c‐means and a nonfuzzy clustering algorithm. Results were compared with volume segmentations by two supervised methods, k‐nearest neighbors and region growing, and all results were compared with manual labelings. Results of individual segmentations are presented as well as comparisons on the application of the different methods with 10 data sets of patients with brain tumors. Unsupervised segmentation is preferred for measuring tumor volumes in response to treatment, as it eliminates operator dependency and may be adequate for delineation of the target volume in radiation therapy. Some obstacles need to be overcome, in particular regard‐big the detection of anatomically relevant tissue classes. This study shows that these improvements are possible.
Measurement of regional aortic compliance by MR imaging: A study of reproducibility
Authors: Forbat Sandy M. , Mohiaddin Raad H. , Yang Guang Z. , Firmin David N. , Underwood S. Richard
Published: March 2007

The reproducibility of MR imaging for the measurement of aortic compliance was studied in 47 healthy volunteers. Long and short term reproducibility and iatraobserver variability were tested. The method was modified to improve image quality and short term reproducibility and intraobserver variability retested. For comparison, spin echo imaging was compared with cine gradient echo imaging. Initial long term reproducibility showed a mean difference (± SE) of 3% (± 7%) with 95% confidence interval (CI) for limits of agreement of ± 69%. Short term reproducibility (7% ± 6%, 95% CI ±46%) and intraobserver variability (1% ± 2%, 95% CI ± 31%) were better. After modification of the technique and optimization of image quality, both short term reproducibility and intraobserver variability improved (0% ± 3%. 95% CI ± 17% and 5% ± 2%, 95% CI ± 16% respectively). Aortic compliance can be measured using spin echo MR imaging with good reproducibility provided care is taken to obtain good quality Images with high spatial resolution.
Renal artery velocity mapping with MR imaging
Authors: Maier Stephan E. , Scheidegger Markus B. , Liu Kecheng , Schneider E. , Bellinger A. , Boesiger Peter
Published: March 2007

An MR phase imaging sequence with a very short echo time was used to assess blood velocity and flow at the renal artery bifurcation. Cardiac‐gated MR imaging data were obtained in six healthy subjects in sagittal planes adjacent to the abdominal aorta and transverse planes above and below the renal artery bifurcation. Average renal artery flow rate was 23.8 ±9 mL/sec. A strong individual variability was found for the velocity profiles in the abdominal aorta during end‐systolic regurgitation. Flow rate was also determined in three patients with reduced renal artery blood flow. Two patients received therapy with percutaneous transluminal angioplasty. The successful outcome was documented with MR imaging. A reliable assessment of renal artery flow with MR phase imaging is feasible. Measurement of the velocity profiles yields valuable insights in the complicated flow regime at the renal artery bifurcation.
Cardiac imaging: Comparison of two‐shot echo‐planar imaging with fast segmented k‐space and conventional gradient‐echo cine acquisitions
Authors: Leung Daniel A. , Debatin Jörg F. , Wildermuth Simon , McKinnon Graeme C. , Von Schulthess Gustav K.
Published: March 2007

We compared the cardiac image quality of multishot echo‐planar imaging (EPI), segmented K‐space, and conventional cine acquisitions. Three techniques were used to obtain gated multiphase acquisitions of an axial section traversing both ventricles in 10 volunteers: two‐shot EPI acquired nonsequentially over two heart beats breath‐held segmented K‐space cine with eight K‐space lines acquired per cardiac trigger over 16 R‐R intervals, also breath‐held and 24 cine phases obtained over 256 R‐R intervals. Intraventricular SNRs with two‐shot EPI were superior to segmented K‐space cine acquisitions (P <.005) and not statistically different from conventional cine acquisitions (P <. 1). Intraventricular signal was most homogeneous on conventional cine images (P <.05). Coronary artery visualization and myocardial delineation were better on the EPI image set than on segmented K‐space cine images (P <.05). Two‐shot EPI provides high‐quality gated cardiac images with an acquisition time of only 2 seconds.
Polo‐like kinase 1 may regulate G2/M transition of mouse fertilized eggs by means of inhibiting the phosphorylation of Tyr15 of Cdc2
Authors: Zhang Zhe , Su Wen‐hui , Feng Chen , Yu Da‐hai , Cui Cheng , Xu Xiao‐yan , Yu Bing‐zhi
Published: March 2007

Polo‐like kinase 1(Plk1) has been reported to be a multifunctional kinase that plays pivotal regulatory roles in microtubule assembly during mammalian early embryonic mitosis. In the present study, we examined the expression of Plk1 at protein and mRNA level in mouse fertilized eggs by Western blot and RT‐PCR. We also examined the kinase activity of Plk1. At various developmental phases of mouse one‐cell stage embryos, both the protein and the mRNA of Plk1 were uniformly distributed; but the kinase activity of Plk1 increased at G2/M phase and decreased at the end of M phase. At the meantime, the phosphorylation of Tyr15 of Cdc2 was inhibited at M phase. To investigate its function in mammalian fertilized eggs further, we used specific short hairpin RNAs (shRNA) and scytonemin, the putative inhibitor of Plk1 to suppress the activity of Plk1 in mouse fertilized eggs. Upon blockage of the activation of with Plk1 shRNA and scytonemin in mouse one‐cell stage embryos, the cleavage rate decreased and the phosphorylation level of Tyr15 of Cdc2 increased. These results imply that the Plk1 may regulate cell cycle progression of mouse fertilized eggs by means of inhibiting the phosphorylation of Tyr15 of Cdc2. Mol. Reprod. Dev. 74: 1247–1254, 2007. © 2007 Wiley‐Liss, Inc.
p19Ink4d and p18Ink4c cyclin‐dependent kinase inhibitors in the male reproductive axis
Authors: Buchold Gregory M. , Magyar Patricia L. , Arumugam Ramamani , Lee Mary M. , O'Brien Deborah A.
Published: March 2007

The loss of the cyclin‐dependent kinase inhibitors (CKIs) p18Ink4c and p19Ink4d leads to male reproductive defects (Franklin et al., 1998. Genes Dev 12: 2899–2911; Zindy et al., 2000. Mol Cell Biol 20: 372–378; Zindy et al., 2001. Mol Cell Biol 21: 3244–3255). In order to assess whether these inhibitors directly or indirectly affect male germ cell differentiation, we examined the expression of p18Ink4c and p19Ink4d in spermatogenic and supporting cells in the testis and in pituitary gonadotropes. Both p18Ink4c and p19Ink4d are most abundant in the testis after 18 days of age and are expressed in purified populations of spermatogenic and testicular somatic cells. Different p18Ink4c mRNAs are expressed in isolated spermatogenic and Leydig cells. Spermatogenic cells also express a novel p19Ink4d transcript that is distinct from the smaller transcript expressed in Sertoli cells, Leydig cells and in other tissues. Immunohistochemistry detected significant levels of p19Ink4d in preleptotene spermatocytes, pachytene spermatocytes, condensing spermatids, and Sertoli cells. Immunoprecipitation‐Western analysis detected both CKI proteins in isolated pachytene spermatocytes and round spermatids. CDK4/6‐CKI complexes were detected in germ cells by co‐immunoprecipitation, although the composition differed by cell type. p19Ink4d was also identified in FSH+ gonadotrophs, suggesting that this CKI may be independently required in the pituitary. Possible cell autonomous and paracrine mechanisms for the spermatogenic defects in mice lacking p18Ink4c or p19Ink4d are supported by expression of these CKIs in spermatogenic cells and in somatic cells of the testis and pituitary. Mol. Reprod. Dev. 74: 997–1007, 2007. © 2007 Wiley‐Liss, Inc.
A loss of status and a sense of defeat: an evolutionary perspective on professional burnout
Authors: Buunk Abraham P. , Peíró José Maria , Rodríguez Isabel , Bravo M. Jesús
Published: March 2007

This longitudinal study among Spanish teachers (N = 558) examined burnout from an evolutionary social rank perspective. The types of stress differed among various school levels, and a sense of defeat was highest among teachers in primary schools. A low status, a loss of status and a sense of defeat were independent cross‐sectional predictors of burnout. Longitudinally a sense of defeat predicted an increase in burnout over time, especially among males and teachers in high schools. The status related variables were in general more important predictors of burnout than stressors that are usually associated with burnout. Copyright © 2007 John Wiley & Sons, Ltd.
Publication Committee Meeting HUPO 5th Annual World Congress Long Beach, CA, USA 30 October 2006
Authors: Orchard Sandra , Heck Albert , Uhlen Mathias , Ping Peipei
Published: March 2007

This meeting brought together delegates from industry, academia and the publishing houses to facilitate discussions on the level of support from the journals for the use of standardised data formats and their interest in the creation of a network of proteomics repositories collaborating on a coordinated data curation effort. Discussions centred on how best to structure interactions between journals, databases and researchers to improve accessibility to data, and facilitate comparisons between datasets.
The numerical analysis of pressure‐flow curves in infancy
Authors: Stocks Janet , Thomson Anne , Silverman Michael
Published: March 2007

Lung resistance (RL) and airway resistance (Raw) were measured in 33 healthy and sick infants. Using strict criteria for quality control, calibrated pressure‐flow (P‐V) curves were produced with the aid of a computer so that resistance could be analyzed at several points over the breathing cycle. In a subgroup of 11 infants from whom simultaneous measurements were obtained, values of RL and Raw were comparable, suggesting that the tissue component may make only a minimal contribution to lung resistance in infants. For both RL and Raw, the P‐V relationship remained linear up to 50% maximum inspiratory flow in all infants. At other points of the respiratory cycle, there were marked changes in resistance, values calculated between points of mid‐isovolume or peak pressure being significantly higher than those measured over the linear portion of inspiratory flow. While no single value can accurately reflect the changes in respiratory resistance that occur during the breathing cycle, the authors suggest that for purposes of comparison, RL or Raw should be measured as the slope of the inspiratory loop from the origin up to 50% of maximum inspiratory flow. From a calibrated tidal pressure flow curve values of resistance over other portions of the breathing cycle can easily be determined.
The effect of age on pulmonary epithelial permeability in unanesthetized lambs
Authors: Hutchison Arlene A. , McNicol Kenneth J. , Loughlin Gerald M.
Published: March 2007

Pulmonary epithelial permeability was measured 1) in unanesthetized sheep, and 2) longitudinally in growing lambs. Awake sheep were intubated and a solution of 51Cr‐ethylenediaminetetraacetic acid and 125I‐antipyrine was instilled in the intrathoracic trachea via the nasotracheal tube. Arterial blood was drawn 1–25 minutes after the instillation. The ratios of the counts of 51Cr to 125I at 7, 10, and 13 min were calculated and averaged for each animal. Data from six adult sheep showed that the mean ± SE of the permeability ratio was 0.012 ± 0.003 and was reproducible over three months. When measured twice within two hours, the second ratio was significantly higher than the first (0.021 ± 0.004 vs. 0.011 ± 0.003, n = 6, P < 0.05). One hour of general anesthesia with methoxyflurane did not alter the permeability ratio significantly. Ten lambs were studied longitudinally 10 hours and 5, 10, 20, and 30 days after delivery. Within the first 24 hours of life the permeability ratio was 0.035 ± 0.007, significantly greater (P < 0.05) than the adult value. At five days there was no significant difference between lambs and adult sheep. Throughout the first month of life, the permeability ratio in lambs remained at the adult level. In summary, 1) pulmonary epithelial permeability can be assessed in awake lambs and adult sheep, 2) the permeability ratio is reproducible for three months but should not be measured within two hours, 3) newborn lambs have a significantly higher ratio than older lambs or adult sheep, and 4) the ratio reaches the adult level within five days after birth.
The effect of systemic hydration on normal and impaired mucociliary function
Authors: Marchette L. C. , Marchette B. E. , Abraham W. M. , Wanner A.
Published: March 2007

Whether systemic hydration enhances the clearance of lower airway secretions in normal lungs and in lungs during antigen‐induced bronchial obstruction was studied. In five conscious allergic sheep, tracheal mucus velocity (TMV) as an index of lower airway mucociliary clearance was measured before and serially for 60 minutes following intravenous infusion of 5% dextrose solution at volumes ranging from 5 to 35 ml/kg. None of these fluid regimens had a significant effect on TMV, although there was a tendency toward a slowing of TMV at the higher volumes of 25 and 35 ml/kg. After producing an acute allergic airway response by inhalation challenge with specific antigen, there was a decrease in mean TMV by 27% and 15% before sham infusion and infusion of 35 ml/kg of dextrose solution, respectively. During the subsequent 60‐minute observation period, mucociliary transport was further impaired by dextrose infusion, with mean TMV being lower after dextrose infusion than after sham infusion at all times of measurement (P < 0.05). The lowest value was reached 30 minutes after dextrose infusion (45% of control). It was concluded that systemic hydration does not significantly alter airway mucociliary transport in the normal state but further impairs mucociliary transport during allergic mucociliary dysfunction. This raises questions regarding the therapeutic role of systemic hydration in the treatment of children and adults who have bronchial asthma.
Respiratory resistance and impedance magnitude in healthy children aged 2–18 years
Authors: Solymar L. , Aronsson P‐H. , Bake B. , Bjure J.
Published: March 2007

Two hundred eighteen healthy children aged 2 to 18 years were studied using a modification of the forced oscillation technique. Reference values with height as predictor were determined for total respiratory resistance and impedance during inspiration, expiration, and throughout the whole respiratory cycle at an oscillation frequency of 4 Hz and, in a subpopulation of 61 children, at frequencies of 2 and 12 Hz. Mean total inspiratory resistance, determined at 4 Hz, decreased with growth from 1.3 kPa.1−1.s at 2 years of age to 0.3 kPa.1−1.s at 18 years. Variability in the results between individuals, expressed in terms of coefficient of variation, was found to be +27% and −21%, respectively, and within individuals, 9%. Resistance during expiration was on average 16% higher than during inspiration and the variability within individuals was 11%. A marked decrease in resistance was found in small children when the frequency was increased from 2 to 12 Hz. The frequency dependence of respiratory resistance observed in small children changes gradually with growth, in parallel with the reduction of total respiratory resistance, to an adult pattern in which no significant change in resistance can be noted between frequencies of 2 and 12 Hz.
The diagnostic effectiveness of the flexible bronchoscope in children
Authors: Wood Robert E.
Published: March 2007

Over a 5‐year period 1,000 pulmonary endoscopic procedures (172 laryngoscopies, 828 bronchoscopies) were performed in children less than 10 years of age using flexible fiberoptic bronchoscopes, with sedation and topical anesthesia. An endoscopic diagnosis of direct relevance to the primary indication for the procedure was established in 76% of the cases; in an additional 15%, abnormalities relevant to a secondary indication were found. Findings were normal in 9% of the cases. The bronchoscope was most useful in the evaluation of patients who had stridor, atelectasis, persistent wheezing, or a suspected foreign body for which there was insufficient evidence to warrant open‐tube bronchoscopy, and for patients who had tracheostomies. The high diagnostic yield and low complication rate strongly support the use of the flexible bronchoscope in the diagnostic evaluation of infants and children who have a variety of pulmonary problems.
Chronic lung disease in children referred to a teaching hospital
Authors: Fernald Gerald W. , Denny Floyd W. , Fairclough Diane L. , Helms Ronald W. , Volberg Frank M.
Published: March 2007

Etiology, symptomatology, and host factors were studied in 184 children referred to a teaching hospital for evaluation in an attempt to classify chronic or potentially chronic lung disease. A standardized historical questionnaire, physical findings, chest radiographs, and a laboratory panel identified a diagnosis that could be related directly or indirectly to chronic lung disease in 22% of the subjects. Among the remaining 78%, bronchiectasis was found in 9%, chronic pneumonia in 9%, chronic diseases with wheezing in 56%, and no significant lower respiratory disease in 4%. Analysis of cases with no apparent etiology revealed that the majority of patients had historical evidence of wheezing; often this previously had not been appreciated. Laboratory tests, such as eosinophil count and immunoglobulin E (IgE) testing, did not differentiate between wheezing and nonwheezing patients. Spirometric evaluation was limited because most subjects were younger than 5 years old. For the same reason, testing for bronchial hyperreactivity was not done. This study reemphasizes that wheezing is a major symptom of chronic lung disease in childhood and provides an outline for its evaluation. Although clinical airways reactivity, as exemplified by wheezing, proved to be the most prominent host defect found in this study, its nature, genetic or otherwise, remains to be defined.
Fetal lung fluid response to maternal hyperosmolality
Authors: Ross Michael G. , Leake Rosemary D. , Ervin PhD M. Gore , Fisher Delbert A.
Published: March 2007

Lung fluid production in utero, a significant source of amniotic fluid, may be regulated by the fetus in response to environmental stress. We monitored changes of maternal and fetal plasma osmolality, plasma arginine vasopressin level, and fetal lung fluid production in response to mannitol‐induced change in maternal osmolality in five chronically catheterized ovine fetuses. Four additional ewes and their fetuses did not receive mannitol and served as controls. Maternal infusion of 20% mannitol resulted in maternal and subsequent fetal hyperosmolality (changing from 303 ± 2 to 322 ± 2 mOsm and 300 ± 5 to 312 ± 8 mOsm, respectively). Mean fetal lung fluid production significantly decreased (from 2.6 ± 0.4 to 1.6 ± 0.4 ml/10 min), whereas lung fluid osmolality significantly increased (from 298 ± 2 to 303 ± 3 mOsm) in the study animals. No changes in lung fluid sodium or potassium concentrations were observed in study or control fetuses. Fetal plasma arginine vasopressin level significantly increased in the study fetuses (2.2 ± 0.3 to 5.3 ± 1.6 μU/ml), though not in control animals. These results indicate that the fetal lamb responds to increased osmolality by decreasing lung fluid production, and that there is a concomitant increase in lung fluid osmolality. This response appears to be mediated via increased fetal plasma vasopressin levels.
Traumatic bronchial injuries in children
Authors: Ein Sigmund H. , Friedberg Jacob , Shandling Barry , Fearon Blair , Filler Robert M.
Published: March 2007

Between 1975 and 1981 five children (three girls and two boys) from 3 to 11 years were treated for blunt chest trauma with major tears in two areas of the right main bronchus. All were hit or run over by motor vehicles and were in acute respiratory distress. All suffered right pneumothoraces; three did not respond to a chest tube with suction. Four of five children had subcutaneous emphysema, and two had fractured ribs on the ipsilateral side; three children also had contralateral chest injuries. Four had major extrathoracic injuries. Three children required early repair, while two needed late treatment. All five patients recovered well and have remained healthy from 5 to 10 years after injury. These cases serve as illustrations for a review of a survey of the literature.
Oxygen and resolution of lung injury
Authors: Tyler Donald C. , Pavlin D. Janet , Boatman E. S. , Nessly Michael , Cheney Frederick W.
Published: March 2007

We investigated the effects of varying inspired oxygen concentrations on the resolution of oleic acid‐induced lung injury in rabbits. Rabbits were injected intravenously with oleic acid and maintained in room air, or exposed to 60, 70, or 80% oxygen for periods of 7 or 10 days. Oleic acid caused hemorrhagic pulmonary edema with hypoxemia. Hypoxemia was more profound in the oxygen‐treated animals, a difference that was significant after 7 days' exposure to 60 and 70% oxygen, and after 4 days to 80% oxygen. Mortality was increased in the animals maintained in 80% oxygen. The data suggest that environmental oxygen concentrations greater than 60% interfere with the return to normal lung function following oleic acid injury in rabbits. The hypoxemia may be due to either mismatching of ventilation and perfusion or to a diffusion block resulting from the increased septal width. There was no evidence of massive pulmonary edema as a cause of the hypoxemia. It was not possible to distinguish between injury primarily caused by oxygen and its interference with the healing process.
Ventilatory response to increased dead spaces in the first week of life
Authors: Stokes G. M. , Carman P. G. T. , Milner A. D. , Morgan D. B. , Wilson A. J. , Oliver M. R.
Published: March 2007

We have developed a method for quantitatively assessing respiratory control in a group of 10 full‐term healthy babies, mean age at test 5 days, by measuring their ventilatory response to added external dead spaces. The dead spaces were equal to 0.5, 1, 2, and 3 anatomic dead spaces (2.2 ml/kg body weight), respectively. Tidal volumes were measured by a nasal mask and a 200‐I rigid container. End‐tidal CO2 was monitored via a tube in the nostril by a mass spectrometer. Baseline measurements were made during a 10‐minute period, after which similar recordings were obtained with each of the dead space tubes. The system was calibrated against a 20‐ml syringe. The mean baseline ventilation was 602 ml/minute. On the addition of 0.5, 1, 2, and 3 dead spaces, minute ventilations were increased by 37.5, 74.7, 150.7, and 273.6%, respectively. These increases were due to rises in tidal volume rather than respiratory rate. End‐tidal CO2 rose by 1.8 and 4 mmHg on the addition of 2 and 3 dead spaces. When the results were compared with expected minute ventilations—based on the baseline recordings and corrected for the added dead spaces and for changes in anatomic dead space ventilation due to alterations in respiratory rate—the results were within 10% of expected values.
Effect of endotracheal continuous positive airway pressure on sensitivity to carbon dioxide and on respiratory timing in preterm infants
Authors: Krauss Alfred N. , Goldstein Ricki F. , Alfero Veronica , Prayer William W. , Auld Peter A. M.
Published: March 2007

To determine the effects of continuous positive airway pressure (CPAP) on ventilatory response to CO2 and inspiratory and expiratory duration in preterm infants, 24 preterm infants with an averase birth weight of 1220 g were studied at a mean age of 10.6 days. CPAP was applied via an uncuffed endotracheal tube. Testings were performed between ambient pressure and a positive airway pressure of 10 cm H2O. Approximately 2/3 of the applied pressure was transmitted to the esophagus. All infants demonstrated a ventilatory response to carbon dioxide of less than 50 ml/min per mm Hg Pco2 at ambient pressure, and no infant showed significant improvement at increasing levels of CPAP. Drive to breathe, as reflected in the inspiratory flow rate (Vt/Ti) also failed to change significantly. It may be concluded that in the apparent absence of significant changes in lung volume, CPAP fails to increase sensitivity to CO2 in preterm infants recovering from hyaline membrane disease.
In vivo response times for a heated skin surface CO2 electrode during rest and exercise
Authors: Nickerson Bruce G. , Patterson Christopher , McCrea Ray , Monaco Frank
Published: March 2007

The continuous, noninvasive estimation of arterial carbon dioxide tension (PaCO2) by heated skin surface electrodes has recently become available for pediatric patients. Skin surface (PsCO2) electrodes can enhance the safety of procedures such as intubation, bronchoscopy, ventilator changes, sleep studies, or measurement of the ventilatory response to CO2 or hypoxia. However, clinical situations that include rapid changes in PaCO2 demand knowledge of the in vivo response time. We compared the response of a heated PsCO2 electrode to end tidal CO2 (PetCO2) during abrupt changes in inspired CO2 from room air to 7% CO2 and back to room air. We obtained 54 curves on nine healthy subjects. There was an initial lag time with less than a 10% change in PsCO2. Then PsCO2 approached PetCO2 exponentially. For subjects at rest changing from breathing room air to 7% CO2, the initial lag time was 46 ± 2 seconds and the 50% response time of the exponential portion was 46 ± 3 seconds. Thus, it took 86 seconds for the electrode to record a 60% response to an abrupt increase in inspired CO2. The initial lag and 50% response time were considerably shorter during exercise (30 ± 2 and 33 ± 2 seconds) and even shorter when switched from breathing 7% CO2 to room air (23 ± 2 and 21 ± 2 seconds). Exercise did not further reduce the response time when CO2 was initially elevated, suggesting the faster response time was due to vasodilation of the skin due to elevated CO2. Users of such electrodes should be aware that changes in ventilation will not be reflected by the CO2 electrode for at least one minute and reaching equilibrium takes several minutes.
Cardiopulmonary function of cats with respiratory distress induced by n‐nitroso n‐methylurethane
Authors: Richardson Peter , Bose Carl L. , Dayton Vanessa , Carlstrom Jeffrey R.
Published: March 2007

The purposes of this study were to determine (1) the effects of positive end‐expiratory pressure (PEEP) and end‐expiratory lung volume on systemic blood flow, (2) whether PEEP levels yielding maximum systemic oxygen transport are associated with maximum lung compliance, and (3) the effects of end‐expiratory lung volume on pulmonary resistance to gas flow, in an animal model of respiratory distress. Twelve cats were inoculated with 12 mg/kg N‐Nitroso N‐Methylurethane (NNNMU) to induce respiratory distress. The NNNMU caused a 76% decrease in disaturated phosphatidyl‐choline of lung lavage, a 34% decrease in functional residual capacity (FRC), an 80% decrease in lung compliance, an 88% increase in pulmonary resistance to gas flow, a 43% decrease in PaO2, and a 37% decrease in oxygen consumption. Systemic blood flow and systemic oxygen transport were not significantly altered by the chemically induced respiratory distress. PEEP levels of 5.1 ± 0.8 cm H2O returned end‐expiratory lung volume to normal FRC levels. Increases in PEEP caused systemic blood flow to decrease even when end‐expiratory lung volume was below or equal to normal FRC levels but did not significantly affect systemic oxygen transport, lung compliance, or pulmonary resistance. We conclude that in cats with NNNMU‐induced respiratory distress: (1) PEEP causes decreases in systemic blood flow, (2) lung compliance and systemic oxygen transport are not clear indicators of optimal PEEP level, and (3) returning end‐expiratory lung volume to normal FRC does not significantly reduce pulmonary resistance to gas flow.
Urokinase therapy for a catheter‐related right atrial thrombus and pulmonary embolism in a 2‐month‐old infant
Authors: Zureikat George Y. , Martin Gerald R. , Silverman Norman H. , Newth Christopher J. L.
Published: March 2007

Thrombolytic therapy seems to be effective in clearins catheter‐related thrombi, allowing subsequent reuse of the Broviac catheter. We have confirmed the previously theoretical risk that thrombolytic therapy in such cases may create pulmonary emboli, but such therapy (in our very limited experience) dissolves the clot extremely quickly. This latter observation may mean that thrombolytic therapy is particularly useful for pulmonary emboli in infants and young children.
Vascular ring: Clinical and physiological assessment of pulmonary function following surgical correction
Authors: Bertrand Jean‐Marie , Chartrand Claude , Lamarre André , Lapierre Jean‐Guy
Published: March 2007

Twelve children were evaluated 7.1 years (mean) after surgical repair of a vascular ring causing tracheal compression. Nine patients complained of persistent respiratory symptoms, mostly cough, dyspnea, and/or wheezing. Functional evaluation revealed abnormal spirometry and/or lung volumes in seven subjects. Analysis of maximal expiratory‐inspiratory flow‐volume loops suggested the presence of residual upper airway obstruction in three patients and peripheral airway obstruction in three others. Eleven patients demonstrated bronchial hyperreactivity to histamine.
Partitioning the respiratory effects of airway citric acid and normal saline in lambs
Authors: Hutchison Alastair A. , Caton Donald , Thomas Ronald G. , Bucciarelli Richard L.
Published: March 2007

Aspiration is common in the intubated human neonate. Thus, the ventilatory and blood gas responses to citric acid and saline instillation into different airway sites were studied in ten awake, unanesthetised lambs, breathing spontaneously via a tracheostomy tube. With a system of balloons, 1 ml of saline or citric acid was placed selectively into the midtrachea, the laryngeal area, or the lower trachea (lower tr). Changes in minute ventilation (V̇E), after a 30 sec baseline period, were measured 30 sec and 1 and 2 min after the challenge. Arterial blood gas changes were measured at 30 sec and 2 min. Major increases in V̇E were seen only when saline or citric acid was instilled into the lower tr, the citric acid responses exceeding saline ones. The arterial oxygen tension (PaO2) fell after lower tr saline, whereas the arterial CO2 tension (Pa) fell with midtracheal saline instillation. A rise in pH and a fall in Pa accompanied citric acid given into the lower tr. An initial rise in PaO2 after citric acid into the lower tr was followed by a return to baseline despite hyperventilation. The ventilatory and blood gas changes with saline and citric acid depend on the site of airway instillation. Pediatr Pulmonol 1987; 3:45–50.
Maximal static pressures and lung volumes in young female swimmers: One year follow‐up
Authors: Zinman Raezelle , Gaultier Claude
Published: March 2007

The relationship between the growth of lung volumes and the development of maximal static pressures was examined in a 1 year follow‐up study of 17 female swimmers, initially less than 12 years of age. Lung volumes were measured by body plethysmography, and maximal static inspiratory and expiratory pressures were generated near residual volume, at functional residual capacity and near total lung capacity (TLC). The results were compared to the regressions obtained from cross‐sectional data generated on 59 girls randomly selected from a local school. Height was similar in swimmers and controls. Vital capacity and total lung capacity increased during the year to exceed normal limits in 11 of 17 swimmers. The only significant increase of maximal static pressures during 1 year occurred in expiration near TLC in those swimmers initially less than 10 years of age, and all pressures fell within normal limits. We conclude that large lung volumes in swimmers cannot be accounted for by an increased ability to inflate and deflate the lung by the respiratory muscles.
Compliance of the total respiratory system in healthy preterm and full‐term newborns
Authors: Migdal M. , Dreizzen E. , Praud J. P. , Vial M. , Dehan M. , Chambille B. , Gaultier C. I.
Published: March 2007

The compliance of the total respiratory system (CRS) was determined by the occlusion technique during expiration in 19 preterm newborns (NB) over 31 weeks of gestational age (mean, 34 ± 1.5 SD) and in 20 full‐term NB. Postnatal age ranged from 1 to 28 days. No sedation was used during the test. In absolute terms, CRS was significantly greater (P < 0.01) in full‐term than in preterm NB (3.17 ± 0.71 ml/cm H2O vs 2.37 ± 0.81 ml/cm H2O). When normalized for body weight, length, body surface area, and the Quetelet index (body weight/length), CRS was similar in preterm and full‐term NB. These results suggest that, normalized for biometric data, passive elastic properties of the total respiratory system are similar in full‐term and preterm NB, at least in the gestation age range studied.
Effect of early furosemide administration in neonates with respiratory distress syndrome
Authors: Belik Jaques , Spitzer Alan R. , Clark Bernard J. , Gewitz Michael H. , Fox William W.
Published: March 2007

The effect of early furosemide‐induced diuresis was prospectively evaluated in 39 neonates less than 24 hr of age with clinical respiratory distress syndrome (RDS) who received either four doses of furosemide (1 mg/kg) or no diuretic. Measurements of Fio2 alveolararterial oxygen gradient (P[A‐a]O2), peak inspiratory pressure (PIP), and urine output as a fraction of intake (O/l) were averaged for every 8 hr. The furosemide group overall showed a significant decrease (P < 0.01) in Fio2, P[A‐a]O2, and PIP with an earlier (32 hr vs 52 hr) and more pronounced diuresis (35% greater O/l) when compared to the controls. This effect was accentuated in the subgroup with 1,000–1,500 g birth weight (significantly lower Fio2 and P(A‐a)o2 from 16 to 48 hours), while no increase in urine output was observed for the infants weighing less than 1,000 g. A significant reduction in supplemental oxygen and need for ventilatory support at 96 hr of age was observed in the furosemide‐treated, less than 1,500‐g infants. The incidence of patent ductus arteriosus was not increased following furosemide therapy, and no significant difference in echocardiographic parameters was observed in 21 infants from both groups, who were followed daily during the first week of life. This study suggests that early furosemide‐induced diuresis, particularly in infants weighing 1,000–1,500 g at birth, promotes improvement in pulmonary functions in RDS and leads to faster reduction in oxygen and ventilatory support.
Effect of pulmonary hypertension on lung compliance in newborn lambs
Authors: Caeton A. John , Goetzman Boyd W. , Bennett Stephen H. , Milstein Jay M.
Published: March 2007

We studied the effects of increased pulmonary arterial pressure and vascular resistance on lung compliance in 12 anesthetized newborn lambs. Lung compliance was unaffected by large changes in pulmonary artery pressure and pulmonary vascular resistance (80% increase) that were induced by either hypoxia or acidosis. We conclude that contraction of the pulmonary vascular smooth muscle in normal newborn lambs does not affect the stiffness of the lung in the parenchymal regions undergoing volume change during ventilation. Pediatr Pulmonol 1987; 3:324–327.
Lung growth and maturation in experimental oligohydramnios in the rat
Authors: Blachford Karen G. , Thurlbeck William M.
Published: March 2007

On day 16 of gestation the amniotic sacs of either the right or left uterine horns of timed‐pregnant Sprague‐Dawley rats were punctured with a 20‐gauge needle. The fetuses of the opposite horn served as controls. On day 21 of gestation (1 day prior to natural delivery), the fetuses were delivered by Cesarean section. Amniotic sac puncture resulted in a significant loss of amniotic fluid. Fetal growth retardation occurred. Lung growth was specifically retarded, as indicated by significantly reduced lung weight to body weight ratios and lung volume to body weight ratios following amniotic sac puncture. There appeared to be no effect on the structural units of the lung, since no differences between control and experimental fetal lungs were observed in terms of deoxyribonucleic acid, nonconnective tissue protein, total phospholipid, and disaturated phosphatidylcholine per gm dry lung weight. The ratios of disaturated phosphatidylcholine to total phospholipid and nonconnective tissue protein to deoxyribonucleic acid were unchanged. The volume proportions of saccular air, saccular wall, bronchial and bronchiolar air and nonparenchyma, peripheral airspace size, and surface‐to‐volume ratio were also unchanged. Thus loss of amniotic fluid significantly affected lung growth, more than it affected overall body growth, without having an effect on lung maturation. Pediatr Pulmonol 1987; 3:328–333.
Performance of respirators at fast rates commonly used in neonatal intensive care units
Authors: Greenough Anne , Greenall F.
Published: March 2007

The effect on tidal volume and airway pressure of increasing ventilator rate (30, 60, and 120/min) was tested in six commonly used neonatal ventilators. In all six ventilators increased flow was necessary to maintain mean airway pressure at the higher rates. Tidal volume decreased at rates of both 60 and 120/min in all six ventilators, associated with a change in pressure waveform. The most marked reduction in tidal volume, however, was associated with increased positive end‐expiratory pressure (PEEP). This was only demonstrated in four ventilators, all incorporating nonassisted expiratory valves. These results stress the necessity for appropriately designed ventilators if fast rates are to be used routinely in clinical practice. Pediatr Pulmonol 1987; 3:357–361.
Pulmonary vascular extraction of circulating norepinephrine in infants with bronchopulmonary dysplasia
Authors: Abman Steven H. , Schaffer Michael S. , Wiggins James , Washington Reginald , Manco‐Johnson Marilyn , Wolfe Robert R.
Published: March 2007

Although the pulmonary circulation in infants with advanced bronchopulmonary dysplasia (BPD) is characterized by abnormal structure and vasoreactivity, metabolic lung functions have not been studied in these infants. To test the hypothesis that patients with severe BPD may have abnormal metabolic lung function, we assessed the pulmonary vascular extraction of circulating norepinephrine in six children with BPD during cardiac catheterization. Plasma norepinephrine levels were measured from simultaneously drawn mixed venous (main pulmonary artery) and left atrium or femoral artery samples. In comparison with four infants with mild heart disease without pulmonary hypertension, we found that infants with BPD extract proportionately less norepinephrine than non‐BPD infants [−7 ± 5% (BPD) versus + 27 ± 6% (non‐BPD); P < 0.001, t test]. Three infants with BPD had higher arterial than mixed venous concentrations of plasma norepinephrine, suggesting net production across the lung. Plasma catecholamine levels and percent extraction correlated poorly with cardiac index and systemic and pulmonary vascular resistance indices. However, this study group was characterized by a high incidence of pulmonary (6/6) and systemic (4/6) hypertension, left ventricular hypertrophy (4/6), and subsequent death (3/6). We conclude that infants with severe BPD and pulmonary hypertension have decreased pulmonary vascular clearance or net production of circulating norepinephrine, but links between altered pulmonary catecholamine metabolism and pulmonary hypertension, or other cardiovascular abnormalities associated with BPD, remain speculative.