Association between dietary vitamin B1 intake and cognitive function among older adults: a cross-sectional study.

BACKGROUND: This study aims to investigate the relationship between vitamin B1 intake and cognitive function in older adults. METHODS: This cross-sectional observational study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. A total of 2422 participants were included in the analysis, with dietary vitamin B1 intake being determined by averaging two 24-h dietary recalls. Cognitive function was assessed using three cognitive function tests: the Digit Symbol Substitution Test (DSST) for processing speed, the Animal Fluency Test (AFT) for executive function, a Consortium to Establish a Registry for Alzheimer's disease (CERAD) subtest for memory. Test-specific and global cognition z score was created. Multivariate linear regression models were used to explore the association between vitamin B1 and cognitive function. RESULTS: 2422 participants, aged 60 years and older, were included from NHANES across two survey cycles (2011-2014). Higher vitamin B1 intake was associated with higher DSST, AFT scores (P < 0.001) as well as the global cognition z score (P = 0.008). In the fully adjusted model, as compared to the lowest quartile (Q1), the highest quartile (Q4) of vitamin B1 intake was related to higher DSST score (ß = 2.23, 95% CI 0.79 ~ 3.67) and global cognition z sore (ß = 0.09, 95% CI 0.02 ~ 0.16). The association between dietary vitamin B1 intake and cognitive function scores in US adults is linear. There was no detected significant statistical interaction between these variables. CONCLUSIONS: Increased dietary intake of vitamin B1 was associated with better cognitive function in individuals aged over 60.

Effect of sevoflurane on CD4+CD25+FOXP3+ regulatory T cells in patients with gastric cancer undergoing radical surgery.

In this study, the proportion of CD4+CD25+FOXP3+ regulatory T (Treg) cells in CD4+ T cells in the peripheral blood of gastric cancer patients before anesthesia induction (T1), after surgery (T2) and the first day after surgery (T3) was studied to explore the effect of sevoflurane and propofol anesthesia on the prognosis of gastric cancer patients. Forty patients with advanced gastric cancer were recruited and randomly divided into the sevoflurane group (S group) and the propofol group (T group). Flow cytometry was used to detect the proportion of CD4+CD25+FOXP3+ Treg cells in CD4+ T cells in the peripheral blood of patients with T1, T2 and T3, respectively. Compared with stage ⅡB, the proportion of CD4+CD25+FOXP3+ Treg cells in T1, T2 and T3 of stage ⅢA and stage ⅢB patients was increased. Compared with the T group, the expression of CD4+CD25+FOXP3+ Treg cells in the peripheral blood of T2 and T3 in the S group was decreased. The results showed that the expression of CD4+CD25+FOXP3+ Treg cells might be related to the TNM stage of gastric cancer and sevoflurane could alleviate the inhibition of postoperative immune function more than propofol. Sevoflurane effectively reduced the expression level of CD4+CD25+FOXP3+ Treg cells in peripheral blood of T2 and T3 of patients with gastric cancer, providing the theoretical basis for the selection of surgical anesthetics for patients with gastric cancer.

Hints for cyclical recruitment of atelectasis during ongoing mechanical ventilation in lavage and oleic acid lung injury detected by SpO2 oscillations and electrical impedance tomography.

PURPOSE OF THE STUDY: Detection of cyclical recruitment of atelectasis after induction of lavage (LAV) or oleic acid injury (OAI) in mechanically ventilated pigs. Primary hypothesis is that oxygen oscillations within the respiratory cycle can be detected by SpO2 recordings (direct hint). SpO2 oscillations reflect shunt oscillations that can only be explained by cyclical recruitment of atelectasis. Secondary hypothesis is that electrical impedance tomography (EIT) depicts specific regional changes of lung aeration and of pulmonary mechanical properties (indirect hint). MATERIALS AND METHODS: Three groups (each n = 7) of mechanically ventilated pigs were investigated applying above mentioned methods before and repeatedly after induction of lung injury: (1) sham treated animals (SHAM), (2) LAV, and (3) OAI. RESULTS: Early oxygen oscillations occurred in the LAV group (mean calculated amplitude: 73.8 mmHg reflecting shunt oscillation of 11.2% in mean). In the OAI group oxygen oscillations occurred hours after induction of lung injury (mean calculated amplitude: 57.1 mmHg reflecting shunt oscillations of 8.4% in mean). The SHAM group had no relevant oxygen oscillations (<30 mmHg, shunt oscillations < 1.5%). Synchronously to oxygen oscillations, EIT depicted (1) a decrease of ventilation in dorsal areas, (2) an increase in ventral areas, (3) a decrease of especially dependent expiratory impedance, 3) an increase in late inspiratory flow especially in the dependant areas, (4) an increase in the speed of peak expiratory flow (PEF), and (5) a decrease of dorsal late expiratory flow. CONCLUSIONS: SpO2 and EIT recordings detect events that are interpreted as cyclical recruitment of atelectasis.

Influence of fluid and volume state on PaO2 oscillations in mechanically ventilated pigs.

Varying pulmonary shunt fractions during the respiratory cycle cause oxygen oscillations during mechanical ventilation. In artificially damaged lungs, cyclical recruitment of atelectasis is responsible for varying shunt according to published evidence. We introduce a complimentary hypothesis that cyclically varying shunt in healthy lungs is caused by cyclical redistribution of pulmonary perfusion. Administration of crystalloid or colloid infusions would decrease oxygen oscillations if our hypothesis was right. Therefore, n=14 mechanically ventilated healthy pigs were investigated in 2 groups: crystalloid (fluid) versus no-fluid administration. Additional volume interventions (colloid infusion, blood withdrawal) were carried out in each pig. Intra-aortal PaO2 oscillations were recorded using fluorescence quenching technique. Phase shift of oxygen oscillations during altered inspiratory to expiratory (I:E) ventilation ratio and electrical impedance tomography (EIT) served as control methods to exclude that recruitment of atelectasis is responsible for oxygen oscillations. In hypovolemia relevant oxygen oscillations could be recorded. Fluid and volume state changed PaO2 oscillations according to our hypothesis. Fluid administration led to a mean decline of 105.3 mmHg of the PaO2 oscillations amplitude (P<0.001). The difference of the amplitudes between colloid administration and blood withdrawal was 62.4 mmHg in pigs not having received fluids (P=0.0059). Fluid and volume state also changed the oscillation phase during altered I:E ratio. EIT excluded changes of regional ventilation (i.e., recruitment of atelectasis) to be responsible for these oscillations. In healthy pigs, cyclical redistribution of pulmonary perfusion can explain the size of respiratory-dependent PaO2 oscillations.

Fatigue self-management: a survey of Chinese cancer patients undergoing chemotherapy.

AIMS AND OBJECTIVES: To examine Chinese cancer patients' fatigue self-management, including the types of self-management behaviours used, their confidence in using these behaviours, the degree of relief obtained and the factors associated with patients' use of fatigue self-management behaviours. BACKGROUND: Fatigue places significant burden on patients with cancer undergoing chemotherapy. While some studies have explored fatigue self-management in Western settings, very few studies have explored self-management behaviours in China. DESIGN: Cross-sectional self- and/or interviewer-administered survey. METHODS: A total of 271 participants with self-reported fatigue in the past week were recruited from a specialist cancer hospital in south-east China. Participants completed measures assessing the use of fatigue self-management behaviours, corresponding self-efficacy, perceived relief levels plus items assessing demographic characteristics, fatigue experiences, distress and social support. RESULTS: A mean of 4.94 (± 2.07; range 1-10) fatigue self-management behaviours was reported. Most behaviours were rated as providing moderate relief and were implemented with moderate self-efficacy. Regression analyses identified that having more support from one's neighbourhood and better functional status predicted the use of a greater number of self-management behaviours. Separate regression analyses identified that greater neighbourhood support predicted greater relief from 'activity enhancement behaviours' and that better functional status predicted greater relief from 'rest and sleep behaviours'. Higher self-efficacy scores predicted greater relief from corresponding behaviours. CONCLUSIONS: A range of fatigue self-management behaviours were initiated by Chinese patients with cancer. Individual, condition and environmental factors were found to influence engagement in and relief from fatigue self-management behaviours. RELEVANCE TO CLINICAL PRACTICE: Findings highlight the need for nurses to explore patients' use of fatigue self-management behaviours and the effectiveness of these behaviours in reducing fatigue. Interventions that improve patients' self-efficacy and neighbourhood supports have the potential to improve outcomes from fatigue self-management behaviours.

Comparison of the characteristics of gut microbiota response to lead in Bufo gargarizans tadpole at different developmental stages.

In amphibians, lead (Pb) exposure could alter the composition and structure of gut microbiota, but changes involving microbiota of several successive phases following Pb exposure have been less studied. In the present study, we compared the effects of Pb exposure on morphological parameters and gut microbiota of Bufo gargarizans at Gosner stage (Gs) 33, Gs36, and Gs42. Our results showed that total length (TL), snout-vent length (SVL), and body wet weight (TW) of B. gargarizans at Gs33, as well as TL and SVL at Gs42, were significantly increased after Pb exposure. In addition, high-throughput sequencing analysis indicated that gut microbiota has distinct responses to Pb exposure at different developmental stages. The diversity of gut microbiota was significantly reduced under Pb exposure at Gs33, while it was significantly increased at Gs42. In terms of community composition, Spirochaetota, Armatimonadota, and Patescibacteria appeared in the control groups at Gs42, but not after Pb treatment. Furthermore, functional prediction indicated that the relative abundance of metabolism pathway was significantly decreased at Gs33 and Gs36, and significantly increased at Gs42. Our results fill an important knowledge gap and provide comparative information on the gut microbiota of tadpoles at different developmental stages following Pb exposure.

Cardiac tamponade, a rare complication of gastric cardia cancer resection after neoadjuvant chemotherapy combined with immunotherapy: a case report and literature review.

Transthoracic cardia resection is a technically well-established surgical procedure. However, acute cardiac tamponade in the early postoperative period is extremely rare. The occurrence is life-threatening to the patient. It also poses a great clinical challenge for perioperative management. To date, few cases of pericardial tamponade have been reported in gastric cancer resection performed after neoadjuvant chemotherapy combined with immunotherapy. We present the case of a 62-year-old woman who received neoadjuvant chemotherapy combined with immunotherapy before surgery, followed by transthoracic surgery. A life-threatening complication, pericardial tamponade, occurred in the early postoperative period. The successful outcome was achieved in through multidisciplinary collaboration.

Corrigendum: Cardiac tamponade, a rare complication of gastric cardia cancer resection after neoadjuvant chemotherapy combined with immunotherapy: a case report and literature review.

[This corrects the article DOI: 10.3389/fonc.2023.1189500.].

Effects of nitrite exposure on metamorphosis and skeletal development of Bufo gargarizans.

Nitrite, as a part of nitrogen cycle, is one of the most common toxic compounds in aquatic ecosystems. Since skeletal development is an essential process during amphibian metamorphosis, exposure of larval amphibians to nitrite might disrupt skeletal development. To evaluate whether nitrite affects skeletal development of amphibian larvae, Bufo gargarizans larvae at Gs26 were exposed to 10, 100, 500 and 1000 µg/L nitrite-nitrogen (NO2-N) in the present study. The metamorphosis rate, body weight, body length, forelimb length and hindlimb length of B. gargarizans exposed to NO2-N were decreased. The microscopic structures of thyroid gland were altered under NO2-N exposure at Gs42. The skeletal lengths of the humerus, femur and fibulare of tadpole at Gs42 were significantly reduced under 100, 500 and 1000 µg/L NO2-N treatment groups, and the lengths of humerus, tibia-fibula and tibiale of tadpole at Gs46 were significantly reduced under 1000 µg/L NO2-N treatment groups. In addition, the expression levels of thyroid hormone (TH) and endochondral ossification-related genes of tadpoles at Gs42 and Gs46 were tested by qRT-PCR. Overall, NO2-N exposure could affect the expressions of these genes and then may influence the activity and function of thyroid gland, further disturbing the amphibian metamorphosis and skeletal development of amphibian larvae.

Morphology and molecular mechanisms of tail resorption during metamorphosis in Rana chensinensis tadpole (Anura: Ranidae).

The tail resorption process was an inevitable and pivotal transformation during amphibian metamorphosis. The present study investigated the mechanisms of tail resorption through histological and transcriptome analysis in Rana chensinensis. The results showed that tail resorption was initiated before the onset of metamorphic climax, and dramatically regressed after metamorphic climax by external-morphology measurement. The drastic disintegration of tail muscle and notochord occurred at Gs42-44, which were consistent with the trend of thyroid follicular cell height. Besides, expression level analysis and functional annotation of DEGs (differentially expressed genes) were conducted through RNA-seq analysis of the tail. Our study also analyzed the expression of genes related to oxidative stress, autophagy, apoptosis and degradation of cellular components in the tail of R. chensinensis. This study enriched the R. chensinensis transcriptome database and laid the foundation of further analysis of tail resorption.

The association between double-lumen tube versus bronchial blocker and postoperative pulmonary complications in patients after lung cancer surgery.

Background: Both double-lumen tube (DLT) and bronchial blocker (BB) are used for lung isolation in patients undergoing lung cancer surgery. However, the effects of different devices for lung isolation remain inconclusive. Present study was designed to investigate the association between the choice of the two devices and postoperative pulmonary complications (PPCs) in patients with lung cancer. Methods: In this retrospective cohort study, patients who underwent lung cancer surgery between January 1, 2020 and October 31, 2020 were screened. Patients were divided into two groups according to different devices for lung isolation: DLT group and BB group. Primary outcome was the incidence of a composite of PPCs during postoperative in-hospital stay. Results: A total of 1721 were enrolled for analysis, of them, 868 received DLT and 853 BB. A composite of PPCs was less common in patients with BB (25.1%, [214/853]) than those received DLT (37.9% [329/868] OR 0.582 95% CI 0.461-0.735 P < 0.001). Respiratory infection was less common in BB group (14.4%, [123/853]) than DLT group (30.3%, [263/868], P<0.001). The incidence of non-PPCs complications was not statistically significant between the 2 groups. Conclusions: For patients undergoing surgery for lung cancer, the use of BB for lung isolation was associated with a reduced risk of PPCs when compared with DLT.

Effects of perchlorate and exogenous T4 exposures on development, metamorphosis and endochondral ossification in Bufo gargarizans larvae.

Several endocrine-disrupting chemicals (EDCs) have been proven to interfere with the physiological function of thyroid hormone (TH), which affected growth and development. However, few studies have investigated the effects of EDCs on TH axis with consequence for skeletal development in amphibians. This study thus examined the potential role of perchlorate and T4 in growth, development and endochondral ossification during metamorphosis of Bufo gargarizans. Our studies showed that NaClO4 treatment caused weight gain and delayed the developmental stage in B. gargarizans tadpoles, while T4 decreased body size and survival rate, accelerated metamorphic duration and increased the risk of early death. Histological sections suggested that NaClO4 and T4 treatments caused damages to thyroid tissue, such as decreased thyroid gland size, follicle size, colloid area, the height of follicular epithelial cells and the number of follicles. In addition, the double skeletal staining and RT-qPCR showed that NaClO4 and T4 treatments inhibited the endochondral ossification by regulating TH synthesis (TRs, Dios) and endochondral ossification-related genes (MMPs, Runxs, VEGFs and VEGFRs) expression levels, which might affect terrestrial locomotion and terrestrial life. Altogether, these thyroid injury and gene expression changes as caused by NaClO4 and T4 may have an influence on development and endochondral ossification during the metamorphosis of amphibians.

Manipulation of cadmium and diethylhexyl phthalate on Rana chensinensis tadpoles affects the intestinal microbiota and fatty acid metabolism.

Gastrointestinal tract and intestine microbiota can both have deep effects on the lipid metabolism and immune function of amphibians. Additionally, the composition and structure of the microbial community are influenced by environmental pollutions. It is noteworthy that environmental compounds such as Cd and DEHP are pervasive in the aquatic environment and do not exist in isolation, and single exposure experiments cannot well explain the effects of unpredictable interactions between co-existing compounds on amphibians. In this study, we calculated the parameters of morphological and histological indices of Rana chensinensis tadpoles after treated with Cd and/or DEHP. The 16S rRNA gene sequencing technology was used to assess the relative abundance of intestinal microbial community among tadpoles from each treatment groups. We also examined the mRNA expression levels of lipid digestion and absorption and SCFAs related-genes. Our results indicated that all morphological and histological indices were significantly declined in the Cd treatment group, while the mixed treatment group was similar to the control group. Compared with the control group, the relative abundances of Firmicutes, Proteobacteria and Verrucomicrobia exhibited distinctive differences in Cd and/or DEHP treatment groups. Further, RT-qPCR results revealed that the expression levels of lipid metabolism and SCFAs related-genes were also significantly altered among the treatment groups. Taken together, the present study highlighted a new evidence that the alterations in intestinal microbial community and mRNA expression levels of larval amphibians after exposure to Cd and/or DEHP may impair lipid storage and transport, as well as reduce anti-inflammatory capacity, which may ultimately lead to a decline in amphibian populations.

Development of mobile health-based self-management support for patients with lung cancer: A stepwise approach.

AIM: To develop self-management support platform on mobile for Chinese patients with lung cancer. DESIGN: A stepwise approach with combination of methods. METHODS: Literature review was carried out to construct preliminary framework and develop detailed content for self-management modules. A semistructured interview was conducted to elicit preference in the content and platform of self-management modules with 15 patients with lung cancer. Delphi study was performed to evaluate and improve the content of modules with 13 experts. A pilot study was conducted to test the mobile health-based self-management support modules with 13 patients with lung cancer. RESULTS: A social network software-based WeChat public account "Symptom Self-Management" for patients with lung cancer was developed and preliminarily tested with positive feedback. Three modules were designed and presented, including symptom management (cancer-related fatigue, cough, dyspnoea, pain, nausea and vomiting), emotion management and role management. CONCLUSION: This study showed that patients with lung cancer have diversified supportive care needs after discharge. A bottom-up and stepwise approach to develop mobile health-based self-management support tool has shown to be feasible and valuable. Theory guidance, user requirement exploration, evidence-based information and expert evaluation are key elements of the process. IMPLICATIONS FOR PRACTICE: The WeChat Public Account "Symptom Self-Management" could be used as sustainable platform to support patients with lung cancer in dealing with common challenges. It provides professional information, self-assessment tools, self-management skills and peer-support platform. Information presented in both text and audio forms enables patients' easy access to the platform.

Intestinal changes associated with nitrite exposure in Bufo gargarizans larvae: Histological damage, immune response, and microbiota dysbiosis.

Nitrite is a ubiquitous toxic compound in aquatic ecosystems and has negative effects on aquatic organisms. The intestine and the trillions of microbes that inhabit it, play an integral role in maintaining digestive and immune functions. However, the effects of nitrite on intestinal health and microflora have been poorly investigated. Therefore, the present study evaluated the response of intestinal histology, immunity, digestive enzyme activities and microbiota to nitrite exposure in Bufo gargarizans tadpoles. The results showed that nitrite caused damage to the intestine and impaired digestive performance. Significant changes in the transcriptional profiles of genes involved in oxidative stress (sod, gpx and hsp), inflammation, and immunity (socs3, il-27, il-1ß and il-17d) were observed in the NO2-N treatment groups. In addition, exposure to nitrite induced alterations of intestinal microbial diversity, structure and composition, suggesting that nitrite may lead to intestinal microbiota dysbiosis. It is noteworthy that probiotics (e.g., Bacteroidetes and Fusobacteria) were decreased after exposure to nitrite, whereas potentially opportunistic pathogens such as Proteobacteria and Enterobacteriaceae were elevated. Functional prediction and correlation analysis suggested that the above changes may interfere with metabolic function and trigger various diseases. Taken together, we concluded that nitrite exposure induced intestinal microbial dysbiosis, which may lead to immune dysfunction and metabolic disorder, and ultimately to histological damages in B. gargarizans. Further, this study will provide a scientific basis for further understanding the risk of nitrite pollution on the intestinal health of amphibians.

Isolation of nine Phytophthora capsici pectin methylesterase genes which are differentially expressed in various plant species.

Phytophthora capsici causes damage on many plants species, and secretes various pectin methylesterases during all stages of infection. We identified nine Pme genes (Pcpme 1-9) from a genomic library of highly virulent P. capsici strain SD33 and further analyzed the expression pattern of nine genes on three hosts: pepper, tomato, and cucumber using qRT-PCR during all stages of infection. All nine genes were found to be differentially expressed in three host species in the course of P. capsici interaction. The expression levels of the respective genes increased from 1 to 7 dpi in pepper, while most genes presented a decreasing trend of expression from 1 to 5 dpi in tomato fruits. However, in both fruits peaks were reached at 7 dpi. In cucumber fruits, each gene showed minor expression levels from 1 to 3 dpi, exhibited definite peaks at 5 dpi, and then decreased from 5 to 7 dpi. Thus, evidence from our studies of Pcpme gene expression in different plants at a rang of time points suggests that the late stages of infection may represent the most critical time for P. capsici to successfully express or/and secret PMEs.

Sevoflurane represses the migration and invasion of gastric cancer cells by regulating forkhead box protein 3.

OBJECTIVE: Previous studies suggested that sevoflurane exerts anti-proliferative, anti-migratory, and anti-invasive effects on cancer cells. To determine the role of sevoflurane on gastric cancer (GC) progression, we evaluated its effects on the proliferation, migration, and invasion of SGC7901, AGS, and MGC803 GC cells. METHODS: GC cells were exposed to different concentrations of sevoflurane (1.7, 3.4, or 5.1% v/v). Cell viability, migration, and invasion were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assays. Immunohistochemical staining and immunoblotting were performed to analyze forkhead box protein 3 (FOXP3) protein expression in tissue specimens and cell lines, respectively. RESULTS: FOXP3 was downregulated in human GC specimens and cell lines. Functionally, FOXP3 overexpression significantly inhibited the proliferation, migration, and invasion of GC cells and accelerated their apoptosis. Moreover, sevoflurane significantly blocked GC cell migration and invasion compared with the findings in the control group. However, FOXP3 silencing neutralized sevoflurane-induced apoptosis and the inhibition of GC cell migration and invasion. Sevoflurane-induced apoptosis and the suppression of migration and invasion might be associated with FOXP3 overactivation in GC cells. CONCLUSIONS: Sevoflurane activated FOXP3 and prevented GC progression via inhibiting cell migration and invasion in vitro.

Development of a CAUTI risk factor evaluation index system for postoperative patients with gynecological malignant tumors.

PURPOSE: In this study, we developed a CAUTI risk factor evaluation index system for postoperative patients with gynecologic malignant tumors and provided scientific evidence for the prevention of catheter-related urinary tract infection (CAUTI). METHODS: A comprehensive method, including literature review, group discussion and Delphi method, was adopted to establish a CAUTI risk factor evaluation index system for postoperative patients with gynecologic malignant tumors. RESULTS: Two rounds of expert consultations resulted in effective response rates of 100%, with authority coefficients of 0.94, and coordination coefficients of 0.473 and 0.388 respectively (p<0.01). The risk factor indicator system consisted of 4 first-level indicators, 13 second-level indicators, and 56 third-level indicators. CONCLUSION: The experts showed high enthusiasm, good authority, and coordination. The CAUTI risk factor evaluation index system for postoperative patients with gynecologic malignant tumors is comprehensive and scientific, and could serve as an important guide for assessment and prevention of CAUTI in patients with gynecologic malignant tumor postoperatively.

Functional analysis of pcpme6 from oomycete plant pathogen Phytophthora capsici.

The Phytophthora capsici inflicts damage on numerous crop plants by secreting a series of pectinase including pectin methylesterase (PME). We identified a PME gene (pcpme6) from a genomic library of a highly virulent P. capsici strain SD33 which had an encoded a polypeptide of 348 amino acid residues with a predicted molecular mass of 38.18 kDa. We also confirmed that pcpme6 was increasingly expressed during symptom development following P. capsici infection of pepper leaves. The wild-type protein (PCPME6) ca. 50 kDa was obtained from pcpme6 expression, and PME activity trend in PCPME6-treated pepper leaves increased with symptom development. PCPME6 degraded leaf cell walls, resulting in the production of necrotic lesions. Mutation of Asp residues in active sites within pcpme6 affected PCPME6 activity and its virulence on pepper leaves. Results show that pcpme6 is a gene within the pme gene family that is important for pathogenesis of P. capsici on pepper.

Observation of ventilation-induced Spo(2) oscillations in pigs: first step to noninvasive detection of cyclic recruitment of atelectasis?

High arterial partial oxygen pressure (Pao(2)) oscillations within the respiratory cycle were described recently in experimental acute lung injury. This phenomenon has been related to cyclic recruitment of atelectasis and varying pulmonary shunt fractions. Noninvasive detection of Spo(2) (oxygen saturation measured by pulse oximetry) as an indicator of cyclic collapse of atelectasis, instead of recording Pao(2) oscillations, could be of clinical interest in critical care. Spo(2) oscillations were recorded continuously in three different cases of lung damage to demonstrate the technical feasibility of this approach. To deduce Pao(2) from Spo(2), a mathematical model of the hemoglobin dissociation curve including left and right shifts was derived from the literature and adapted to the dynamic changes of oxygenation. Calculated Pao(2) amplitudes (derived from Spo(2) measurements) were compared to simultaneously measured fast changes of Pao(2), using a current standard method (fluorescence quenching of ruthenium). Peripheral hemoglobin saturation was capable to capture changes of Spo(2) within each respiratory cycle. For the first time, Spo(2) oscillations due to cyclic recruitment of atelectasis within a respiratory cycle were determined by photoplethysmography, a technology that can be readily applied noninvasively in clinical routine. A mathematic model to calculate the respective Pao(2) changes was developed and its applicability tested.