Direct surface analysis mass spectrometry uncovers the vertical distribution of cuticle-associated metabolites in plants.

The plant cuticle covers the plant's entire aerial surface and acts as the outermost protective layer. Despite being crucial for the survival of plants, surprisingly little is known about its biosynthesis. Conventional analytical techniques are limited to the isolation and depolymerization of the polyester cutin, which forms the cuticular scaffold. Although this approach allows the elucidation of incorporated cutin monomers, it neglects unincorporated metabolites participating in cutin polymerization. The feasibility of a novel approach is tested for in situ analysis of unpolymerized cuticular metabolites to enhance the understanding of cuticle biology. Intact cotyledons of Brassica napus and Arabidopsis thaliana seedlings are immersed in organic solvents for 60 seconds. Extracts are analyzed using high-resolution direct infusion mass spectrometry. A variety of different diffusion routes of plant metabolites across the cuticle are discussed. The results reveal different feasibilities depending on the research question and cuticle permeabilities in combination with the analyte's polarity. Especially hydrophilic analytes are expected to be co-located in the cell wall beneath the cuticle causing systematic interferences when comparing plants with different cuticle permeabilities. These interferences limit data interpretation to qualitative rather than quantitative comparison. In contrast, quantitative data evaluation is facilitated when analyzing cuticle-specific metabolites or plants with similar cuticle permeabilities.

Emerging investigator series: aqueous-phase processing of atmospheric aerosol influences dissolution kinetics of metal ions in an urban background site in the Po Valley.

Metals are an important atmospheric aerosol component; their impacts on health and the environment depend also on their solubility, dissolution kinetics and chemical form in which they are present in the aerosol (e.g., oxidation state, inorganic salt or oxide/hydroxide, organic complex). In this study, we investigated the impact of fog processing on the solubility and dissolution of metals in PM2.5 samples collected in an urban background site in Padova (Italy). For each sample, we determined the solubility and dissolution kinetics of 17 elements in a solution simulating fog water in the winter season in the Po Valley (pH 4.7, T 5 °C, and water content ∼0.5 g m-3). We also determined water-soluble inorganic and organic compounds having ligand properties. We used the model E-AIM IV to calculate the aerosol liquid water (ALW) content and pH, and we used the model Visual MinteQ to determine the speciation picture of the most important elements under conditions of both deliquescent aerosol (ALW and pH calculated using E-AIM IV, ambient temperature) and simulated fog. We found that the dissolution of Al, Cu, and Fe metal ions, predicted to be largely coordinated with organic compounds under fog conditions, was either immediate or considerably faster in samples collected on days with observed fog events compared with those collected on days having drier conditions. For readily soluble elements, such as As, Cd, Cr, Sr, and Zn, such an effect was not observed. Our study highlights the importance of coordination chemistry in atmospheric aerosol and fog in determining the bioavailability of particle-bound metals.

A rhabdomyosarcoma hydrogel model to unveil cell-extracellular matrix interactions.

Three-dimensional (3D) culture systems have progressively attracted attention given their potential to overcome limitations of classical 2D in vitro systems. Among different supports for 3D cell culture, hydrogels (HGs) offer important advantages such as tunable mechanical and biological properties. Here, a biocompatible hyaluronic acid-polyethylene glycol HG was developed to explore the pro-migratory behavior of alveolar rhabdomyosarcoma (ARMS) cells. Proteomic analysis of ARMS xenografts unveiled the composition of the extracellular matrix (ECM) elucidating the most representative proteins. In parallel, HGs were obtained by the combination of a thiol-containing hyaluronic acid derivative and different polyethylene glycol (PEG) dimaleimide polymers. The selection of the optimal HG for ARMS cell growth was made based on degradation time, swelling, and cell distribution. Rheology measures and mechanical properties were assessed in the presence or absence of ECM proteins (collagen type I and fibronectin), as well as viability tests and cell distribution analysis. The role of ITGA5, the receptor of fibronectin, in determining ARMS cell migration was validated in vitro upon ITGA5 silencing. In vivo, cell dissemination and the capacity for engrafting were validated after injecting ARMS cell populations enriched for the level of ITGA5 in zebrafish embryos. To study the interactions with ARMS-specific ECM proteins (HG + P), the key players from the Rho and heat-shock pathways were investigated by reverse phase protein array (RPPA). Our data suggest that the developed 3D ARMS model is useful for identifying potential physical hallmarks that allow cancer cells to resist therapy, escape from the immune-system and increase dissemination.

Circulating Biomarkers for Response Prediction of Rectal Cancer to Neoadjuvant Chemoradiotherapy.

Rectal cancer response to neoadjuvant Chemoradiotherapy (pCRT) is highly variable. In fact, it has been estimated that only about 21 % of patients show pathologic Complete Response (pCR) after therapy, while in most of the patients a partial or incomplete tumour regression is observed. Consequently, patients with a priori chemoradioresistant tumour should not receive the treatment, which is associated with substantial adverse effects and does not guarantee any clinical benefit. For Locally Advanced Rectal Cancer Patients (LARC), a standardized neoadjuvant treatment protocol is applied, the identification and the usefulness of prognostic or predictive biomarkers can improve the antitumoural treatment strategy, modifying the sequence, dose, and combination of radiotherapy, chemotherapy and surgical resection. For these reasons, a growing number of studies are actually focussed on the discovery and investigation of new predictive biomarkers of response to pCRT. In this review, we have selected the most recent literature (2012-2017) regarding the employment of blood-based biomarkers potentially predicting pCR in LARC patients and we have critically discussed them to highlight their real clinical benefit and the current limitations of the proposed methodological approaches.

Formation of metal-organic ligand complexes affects solubility of metals in airborne particles at an urban site in the Po valley.

Metals in atmospheric aerosols play potentially an important role in human health and ocean primary productivity. However, the lack of knowledge about solubility and speciation of metal ions in the particles or after solubilisation in aqueous media (sea or surface waters, cloud or rain droplets, biological fluids) limits our understanding of the underlying physico-chemical processes. In this work, a wide range of metals, their soluble fractions, and inorganic/organic compounds contained in urban particulate matter (PM) from Padua (Italy) were determined. Metal solubility tests have been performed by dissolving the PM in water and in solutions simulating rain droplet composition. The water-soluble fractions of the metal ions and of the organic compounds having ligand properties have been subjected to a multivariate statistical procedure, in order to elucidate associations among the aqueous concentrations of these PM components in simulated rain droplets. In parallel, a multi-dimensional speciation calculation has been performed to identify the stoichiometry and the amount of metal-ligand complexes theoretically expected in aqueous solutions. Both approaches showed that the solubility and the aqueous speciation of metal ions were differently affected by the presence of inorganic and organic ligands in the PM. The solubility of Al, Cr, and Fe was strongly correlated to the concentrations of oxalic acid, as their oxalate complexes represented the expected dominant species in aqueous solutions. Oxalates of Al represented ∼98% of soluble Al, while oxalates of Cu represented 34-75% of the soluble Cu, and oxalates of Fe represented 76% of soluble Fe. The oxidation state of Fe can strongly impact the speciation picture. If Fe is present as Fe(II) rather than Fe(III), the amount of Cr and Cu complexed with diacids can increase from 75% to 94%, and from 32% to 53%, respectively. For other metals, the solubility depended on the formation of soluble aquo-complexes, hence with a scarce effect of the organic ligands. An iron-oxalate complex was also directly detected in aerosol sample extracts.

Evidence of noncovalent complexes in some natural extracts: Ceylon tea and mate extracts.

Considering the high complexity of natural extracts, because of the presence of organic molecules of different chemical nature, the possibility of formation of noncovalent complexes should be taken into account. In a previous investigation, the formation of bimolecular complexes between caffeine and catechins in green tea extracts (GTE) has been experimentally proven by means of mass spectrometric and 1 H nuclear magnetic resonance experiments. The same approaches have been employed in the present study to evaluate the presence of bimolecular complexes in Ceylon tea and mate extracts. The obtained results show that in the case of Ceylon tea extracts, protonated theaflavin is detectable, together with theaflavin/caffein complexes, while caffeine/catechin complexes, already detected in green tea, are still present but at lower concentration. This aspect is evidenced by the comparison of precursor ion scans performed on protonated caffeine for the two extracts. The spectra obtained in these conditions for GTE and Ceylon tea show that the complexes of caffeine with epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG), highy abundant in the case of GTE (signal-to-chemical noise ratio in the range 50-100), are negligible (signal-to-chemical noise ratio in the range 2-3) in the case of Ceylon tea. Mate extracts show the formation of bimolecular complexes involving caffeine but not catechins, and chlorogenic acid becomes responsible for other complex formation. Under positive ion and negative ion conditions, accurate mass measurements allow the identification of malealdehyde, chlorogenic acid, caffeine, two isomers of dicaffeoylquinic acid, rutin, and kaempferol-3-O-rutinoside. These data indicate that the formation of complexes in natural extracts is a common behavior, and their presence must be considered in the description of natural extracts and, consequently, in their biological activity.

The role of mass spectrometry in studies of glycation processes and diabetes management.

In the last decade, mass spectrometry has been widely employed in the study of diabetes. This was mainly due to the development of new, highly sensitive, and specific methods representing powerful tools to go deep into the biochemical and pathogenetic processes typical of the disease. The aim of this review is to give a panorama of the scientifically valid results obtained in this contest. The recent studies on glycation processes, in particular those devoted to the mechanism of production and to the reactivity of advanced glycation end products (AGEs, AGE peptides, glyoxal, methylglyoxal, dicarbonyl compounds) allowed to obtain a different view on short and long term complications of diabetes. These results have been employed in the research of effective markers and mass spectrometry represented a precious tool allowing the monitoring of diabetic nephropathy, cardiovascular complications, and gestational diabetes. The same approaches have been employed to monitor the non-insulinic diabetes pharmacological treatments, as well as in the discovery and characterization of antidiabetic agents from natural products. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 38:112-146, 2019.

Reduced Plasma Levels of Very-Long-Chain Dicarboxylic Acid 28:4 in Italian and Brazilian Colorectal Cancer Patient Cohorts.

BACKGROUND: There are currently no blood-based biomarkers for early diagnosis of colorectal cancer. Previous research has suggested that very-long-chain dicarboxylic acid (VLCDCA) 28:4 might be such a biomarker. METHODS: Using high-resolution mass spectrometry, we analyzed VLCDCA 28:4 in the plasma of colorectal cancer patients in Italian [n = 62] and Brazilian [n = 52] cohorts. Additionally, we investigated individuals diagnosed with familial adenomatous polyposis (FAP; n = 27), one of the most important clinical forms of inherited susceptibility to colorectal cancer. Results: Decrements in plasma levels of VLCDCA 28:4 were monitored in colorectal cancer patients. These decreases were independent of the stage of tumor development and the individual's age. However, no decrements in VLCDCA 28:4 were monitored in FAP patients. CONCLUSIONS: The plasma levels of VLCDCA 28:4 represent a potential biomarker of sporadic colorectal cancer. In addition, it is possible that resupply of this anti-inflammatory lipid may represent a new therapeutic strategy for CRC and inflammatory disorders.

Preclinical three-dimensional colorectal cancer model: The next generation of in vitro drug efficacy evaluation.

Colorectal cancer (CRC), the third most common cancer diagnosed in both men and women in the United States, shows a highly ineffective therapeutic management. In these years neither substantial improvements nor new therapeutic approaches have been provided to patients. Performing the early lead discovery phases of new cancer drugs in cellular models, resembling as far as possible the real in vivo tumor environment, may be more effective in predicting their future success in the later clinical phases. In this review, we critically describe the most representative bioengineered models for anticancer drug screening in CRC from the conventional two-dimensional models to the new-generation three-dimensional scaffold-based ones. The scaffold aims to replace the extracellular matrix, thus influencing the biomechanical, biochemical, and biological properties of cells and tissues. In this scenario, we believe that reconstitution of tumor condition is mandatory for an alternative in vitro methods to study cancer development and therapeutic strategies.

Experimental Evidence of the Presence of Bimolecular Caffeine/Catechin Complexes in Green Tea Extracts.

A hypothesis on the peculiar pharmacological behavior of biologically active natural compounds is based on the occurrence of molecular interactions originating from the high complexity of the natural matrix, following the rules of supramolecular chemistry. In this context, some investigations were performed to establish unequivocally the presence of caffeine/catechin complexes in green tea extracts (GTEs). 1H NMR spectroscopy was utilized to compare profiles from GTEs with caffeine/catechin mixtures in different molar ratios, showing that peaks related to caffeine in GTEs are generally upfield shifted compared to those of free caffeine. On the other hand, ESIMS experiments performed on GTE, by means of precursor ion scan and neutral loss scan experiments, proved unequivocally the presence of caffeine/catechin complexes. Further investigations were performed by an LC-MS method operating at high-resolution conditions. The reconstructed ion chromatograms of the exact mass ions corresponding to caffeine/catechin species have been obtained, showing the presence of complexes of caffeine with gallate-type catechins. Furthermore, this last approach evidenced the presence of the same complex with different structures, consequently exhibiting different retention times. Both MSE and product ion MS/MS methods confirm the nature of caffeine/catechin complexes of the detected ions, showing the formation of protonated caffeine.

Analytical aspects of sunitinib and its geometric isomerism towards therapeutic drug monitoring in clinical routine.

Sunitinib malate, an oral multi-targeted tyrosine kinase inhibitor approved for the treatment of metastatic renal cell carcinoma, gastrointestinal stromal tumor, and well-differentiated pancreatic neuroendocrine tumors, has been identified as a potential candidate for therapeutic drug monitoring approach. Nevertheless, the development of an analytical assay suitable for clinical application for the quantification of the plasma concentration of sunitinib and its active metabolite, N-desethyl sunitinib, is limited by its Z/E isomerization when exposed to light. Several LC-MS/MS methods already published require protection from light during all sample handling procedures to avoid the formation of E-isomer, which makes them not suitable for clinical practice. In order to obtain a simple and fast procedure to reconvert the E-isomer, formed during sample collection and treatment without light protection, and, thus, to have only Z-isomer peak to quantify, we studied the Z/E photodegradation with special attention to the condition allowing the reverse reaction in plasma matrix. After 30 min of light exposure, the E-isomer maximum percentage of both the analytes was reached (44% of E-sunitinib and 20% of E-N-desethyl sunitinib; these percentages were calculated with respect to the sum of E + Z). Moreover, the formation of the E-isomer increased up to 20% after lowering the pH of the solution. Since the reverse reaction takes place when the pre-exposed solution is placed in dark, we followed the E to Z-isomer kinetics into the autosampler. The conversion rate was very slow when the autosampler was set at 4 °C (after 4 h the mean percentages of E-isomer were 50% for sunitinib and 22% for N-desethyl sunitinib). The reconversion rate was considerably accelerated with the increasing of the temperature: incubating the analytical solution in a heated water bath for 5 min at 70 °C we obtained the quantitative (99%) reconversion of the E- to the Z-isomer. No effect of concentration was observed, while the presence of acids inhibited the reconversion. Based on these results, a simple and fast procedure was setup to quantitatively reconvert the E-isomer formed during sample collection and processing without light protection into its Z-form thus leading to a single peak to quantify. The application of this additional step allows to develop a LC-MS/MS method suitable to clinical practice, due to its practicality and speed.

Liposomal delivery of a Pin1 inhibitor complexed with cyclodextrins as new therapy for high-grade serous ovarian cancer.

Pin1, a prolyl isomerase that sustains tumor progression, is overexpressed in different types of malignancies. Functional inactivation of Pin1 restrains tumor growth and leaves normal cells unaffected making it an ideal pharmaceutical target. Although many studies on Pin1 have focused on malignancies that are influenced by sex hormones, studies in ovarian cancer have lagged behind. Here, we show that Pin1 is an important therapeutic target in high-grade serous epithelial ovarian cancer. Knock down of Pin1 in ovarian cancer cell lines induces apoptosis and restrains tumor growth in a syngeneic mouse model. Since specific and non-covalent Pin1 inhibitors are still limited, the first liposomal formulation of a Pin1 inhibitor was designed. The drug was efficiently encapsulated in modified cyclodextrins and remotely loaded into pegylated liposomes. This liposomal formulation accumulates preferentially in the tumor and has a desirable pharmacokinetic profile. The liposomal inhibitor was able to alter Pin1 cancer driving-pathways trough the induction of proteasome-dependent degradation of Pin1 and was found to be effective in curbing ovarian tumor growth in vivo.

The maternal-fetal gradient of free and esterified phytosterols at the time of delivery in humans.

BACKGROUND: High dietary intakes of phytosterols (Phyto), such as those consumed by vegans and vegetarians, are not recommended for cholesterol-lowering in pregnant women (PW) because the safety of their use during pregnancy has not been fully established [1]. Information on Phyto in pregnancy is very limited. OBJECTIVE: To characterize the maternal-fetal gradient of free and esterified Phyto at the time of delivery in humans. DESIGN: PW who had a term delivery at the Obstetrics and Gynecology Unit of the University Hospital of Padua (Padua, Italy), between November 2016 and March 2017, participated in the study. Fatty acids (FA), cholesterol (Chol), Chol metabolites (7-dehydrocholesterol, 7-DHChol; lathosterol, Latho; 7α-hydroxycholesterol, 7α-OHChol), and Phyto (campesterol, Camp; stigmasterol, Stigma; sitosterol, Sito) were measured in both maternal (MB) and cord blood (CB) at the time of delivery. Non-pregnant adult volunteers (Ref-NA) served as a reference. RESULTS: Thirty-four term PW and 12 Ref-NA signed informed consent and were studied. Plasma total Phyto concentrations in CB were up to 20-fold lower than in MB (p < 0.05). Positive and significant correlations were found between total Phyto of MB-CB pairs (p < 0.01), and between total FA and Camp of MB (p < 0.05). Interestingly, free Chol to Chol ester ratio of CB did not differ from that of MB, and free Phyto to Phyto ester ratios were higher in CB than in MB (p < 0.001). No differences were found between Phyto concentrations of MB and Ref-NA. However, free Chol to Chol ester ratio, and free Phyto to Phyto ester ratios were higher in MB than in Ref-NA (p < 0.05). Chol synthesis, as indicated by 7-DHChol to 7α-OHChol, Latho to 7α-OHChol, and Latho to Sito ratios, was greatest in CB and lowest in Ref-NA. CONCLUSION: Our data suggest that free Phyto cross the human placenta more easily than Phyto ester. An elevated Stigma to Chol ratio in CB than in MB was also described for the first time. The impact of these findings on the neonatal outcomes remains to be elucidated.

Glial fibrillary acidic protein plasma levels are correlated with degree of hypothermia during cardiopulmonary bypass in congenital heart disease surgery.

Objectives: Improved congenital heart defect (CHD) operations have reduced operative mortality to 3%. The major concern is now long-term neurological outcomes. We measured plasma glial fibrillary acidic protein (GFAP), an early marker of brain injury, during different phases of cardiopulmonary bypass (CPB), to correlate the increase of GFAP to clinical parameters or specific operative phases. Methods: We performed a prospective, single-centre, observational study in children undergoing cardiac operations. We studied 69 children with CHD and biventricular heart physiology: 26 had tetralogy of Fallot; 17 transposition of the great arteries; and 26 ventricular/atrial septal defects with or without associated arch defects. GFAP levels were measured by ELISA at different stages of CPB. We recorded clinical and surgical parameters and applied multivariable and logistic regressions to assess which parameters were independent predictors of variations in plasma GFAP. Results: GFAP increased during CPB and peaked at the end of rewarming. Multivariable regression showed degree of hypothermia as the only significant independent predictor of GFAP increase, adjusted for age, prematurity, type of CHD, cyanosis, aortic cross-clamp time, haemodilution, neurological risk time interval and rewarming rate. Temperature nadir and neurological risk time interval were significant independent predictors of a GFAP value > 0.46 ng/ml. Conclusions: Hypothermia degree during CPB is correlated with GFAP plasma increase in children with biventricular heart defects undergoing surgical repair. Rewarming is the most critical CPB phase for GFAP increase. The implication of high plasma GFAP is still under evaluation. Follow-up studies are ongoing to assess the reliability of GFAP as a marker of brain injury and/or as a predictor of neurodevelopmental abnormalities.

Field-assisted paper spray mass spectrometry for the quantitative evaluation of imatinib levels in plasma.

Drug levels in patients' bloodstreams vary among individuals and consequently therapeutic drug monitoring (TDM) is fundamental to controlling the effective therapeutic range. For TDM purposes, different analytical approaches have been used, mainly based on immunoassay, liquid chromatography- ultraviolet, liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. More recently a matrix-assisted laser desorption/ionisation method has been proposed for the determination of irinotecan levels in the plasma of subjects under therapy and this method has been cross- validated by comparison with data achieved by LC-MS/MS. However, to reach an effective point-of-care monitoring of plasma drug concentrations, a TDM platform technology for fast, accurate, low-cost assays is required. In this frame, recently the use of paper spray mass spectrometry, which is becoming a popular and widely employed MS method, has been proposed. In this paper we report the results obtained by the development of a paper spray-based method for quantitative analysis in plasma samples of imatinib, a new generation of anticancer drug. Preliminary experiments showed that poor sensitivity, reproducibility and linear response were obtained by the "classical" paper spray set-up. In order to achieve better results, it was thought of interest to operate in presence of a higher and more homogeneous electrical field. For this aim, a stainless steel needle connected with the high voltage power supply was mounted below the paper triangle. Furthermore, in order to obtain valid quantitative data, we analysed the role of the different equilibria participating to the phenomena occurring in paper spray experiments, depending either on instrumental parameters or on the chemical nature of analyte and solvents. A calibration curve was obtained by spiking plasma samples containing different amounts of imatinib (1) with known amounts of deuterated imatinib (1d3) as internal standard, with molar ratios [1]/[1d3] in the range 0.00-2.00. A quite good linearity was obtained (R2 = 0.975) and some experiments performed on spiked plasma samples with known amounts of 1 confirmed the validity of this method.

Cardiopulmonary Bypass Increases Plasma Glial Fibrillary Acidic Protein Only in First Stage Palliation of Hypoplastic Left Heart Syndrome.

BACKGROUND: Univentricular congenital heart defects require open-heart surgery soon after birth, and are associated with risk of brain injury and poor neurologic outcome. METHODS: This is a prospective, observational study on children undergoing cardiac surgery. Plasma glial fibrillary acidic protein (GFAP), as an early marker of brain injury, was measured by ELISA at the end of anaesthesia induction, initiation of cardiopulmonary bypass (CPB), the end of cooling, the end of rewarming, the end of CPB, and after protamine administration. We recorded clinical and surgical parameters to assess which CPB phase and clinical parameters were associated with a GFAP increase. RESULTS: We studied 13 children less than 50 months of age: 8 underwent Norwood or Damus-Kaye-Stansel palliation (group 1) and 5 underwent Fontan procedure (group 2). A GFAP increase was only observed in group 1, with the highest median value at the end of rewarming. No quantifiable levels of GFAP were measured at pre-bypass and the start of CPB stages in all patients. End of cooling and CPB-end GFAP, GFAP maximum value, and GFAP area under the curve all correlated with the CPB time spent at a cerebral regional saturation < 45% (P = 0.021, 0.028, 0.007, 0.021, respectively). CONCLUSIONS: Children with univentricular heart defects exhibit a CPB plasma-GFAP increase only after stage 1 palliation. The maximum GFAP increase occurred at the end of rewarming. Further studies are needed to identify which clinical or surgical parameter(s) could reflect a GFAP increase during surgery for congenital heart defects, and whether GFAP levels correlate with the neurologic outcome.

Surfactant protein B and A concentrations are increased in neonatal pneumonia.

BACKGROUND: Term newborns with pneumonia show a reduced pulmonary compliance due to multiple and ill-defined factors. Surfactant proteins' (SPs) changes could have a role in the reduced compliance but the matter is still unsettled. The aim of this study was to clarify the meaning of SPs changes during pneumonia in term newborns. METHODS: In 28 term ventilated newborns, 13 with pneumonia and 15 with no lung disease, we measured SP-B, SP-A, disaturated-phosphatidylcholine (DSPC), and total phospholipids (PL) concentrations in tracheal aspirates at intubation and close to extubation. We also measured DSPC kinetics using (U-(13)C-PA)dipalmitoyl-phosphatidylcholine. RESULTS: At baseline, SP-B, expressed as % of PL, was significantly different between the groups, being 3.5-fold higher in pneumonia than controls. Conversely, SP-A did not vary between the groups. At extubation, SP-B and SP-A concentrations had decreased significantly in newborns with pneumonia, while there was no significant change in controls. DSPC t1/2 was significantly shorter in the pneumonia group (11.8 (5.5-19.8) h vs. 26.6 (19.3-63.6) h, P = 0.011). CONCLUSION: In term newborns with pneumonia, SP-B increases with respect to PL, and DSPC is turned over at a faster rate. Disease's resolution is associated with the restoration of the normal ratio between SP-B and PL.