Exercise training improves neurovascular control and functional capacity in heart failure patients regardless of age

Background: Exercise training is a non-pharmacological strategy for treatment of heart failure. Exercise training improves functional capacity and quality of life in patients. Moreover, exercise training reduces muscle sympathetic nerve activity (MSNA) and peripheral vasoconstriction. However, most of these studies have been conducted in middle-aged patients. Thus, the effects of exercise training in older patients are much less understood. The present study was undertaken to investigate whether exercise training improves functional capacity, muscular sympathetic activation and muscular blood flow in older heart failure patients, as it does in middle-aged heart failure patients. Design: Fifty-two consecutive outpatients with heart failure from the database of the Unit of Cardiovascular Rehabilitation and Physiology Exercise were divided by age (middle-aged, defined as 45-59 years, and older, defined as 60-75 years) and exercise status (trained and untrained). Methods: MSNA was recorded directly from the peroneal nerve using the microneurography technique. Forearm Blood Flow (FBF) was measured by venous occlusion plethysmography. Functional capacity was evaluated by cardiopulmonary exercise test. Results: Exercise training significantly and similarly increased FBF and peak VO2 in middle-aged and older heart failure patients. In addition, exercise training significantly and similarly reduced MSNA and forearm vascular resistance in these patients. No significant changes were found in untrained patients. Conclusion: Exercise training improves neurovascular control and functional capacity in heart failure patients regardless of age.

DSD Due to 5 alpha-Reductase 2 Deficiency - from Diagnosis to Long Term Outcome

Most of the patients with 5 alpha-RD 2 deficiency are reared in the female social sex due to their severely undervirilized external genitalia but similar to 60% who have not been submitted to orchiectomy in childhood undergo male social sex change at puberty. In our cohort of 30 cases from 18 families, all subjects were registered in the female social sex except for two children-one who had an affected uncle and the other who was diagnosed before being registered. The majority of the patients were satisfied with the long-term results of their treatment and surprisingly, penile length was not associated with satisfactory or unsatisfactory sexual activity. Steroid 5 alpha-RD2 deficiency should be included in the differential diagnosis of all newborns with 46,XY DSD with normal testosterone production before gender assignment or any surgical intervention because these patients should be considered males at birth.

Mechanisms of blunted muscle vasodilation during peripheral chemoreceptor stimulation in heart failure patients

We described recently that systemic hypoxia provokes vasoconstriction in heart failure (HF) patients. We hypothesized that either the exaggerated muscle sympathetic nerve activity and/or endothelial dysfunction mediate the blunted vasodilatation during hypoxia in HF patients. Twenty-seven HF patients and 23 age-matched controls were studied. Muscle sympathetic nerve activity was assessed by microneurography and forearm blood flow (FBF) by venous occlusion plethysmography. Peripheral chemoreflex control was evaluated through the inhaling of a hypoxic gas mixture (10% O-2 and 90% N-2). Basal muscle sympathetic nerve activity was greater and basal FBF was lower in HF patients versus controls. During hypoxia, muscle sympathetic nerve activity responses were greater in HF patients, and forearm vasodilatation in HF was blunted versus controls. Phentolamine increased FBF responses in both groups, but the increase was lower in HF patients. Phentolamine and N-G-monomethyl-L-arginine infusion did not change FBF responses in HF but markedly blunted the vasodilatation in controls. FBF responses to hypoxia in the presence of vitamin C were unchanged and remained lower in HF patients versus controls. In conclusion, muscle vasoconstriction in response to hypoxia in HF patients is attributed to exaggerated reflex sympathetic nerve activation and blunted endothelial function (NO activity). We were unable to identify a role for oxidative stress in these studies. (Hypertension. 2012; 60: 669-676.) . Online Data Supplement

Estudo do Padrão Respiratório e Movimento Toracoabdominal em Valvopatia Mitral

FUNDAMENTO: pacientes com valvopatia mitral podem evoluir com congestão pulmonar, que aumenta o trabalho dos músculos respiratórios; essa sobrecarga pode alterar o padrão respiratório com predomínio do deslocamento torácico ou presença de movimentos paradoxais. OBJETIVO: a) estudar o padrão respiratório e movimento toracoabdominal (MTA) em pacientes com doença mitral b) estudar o efeito do posicionamento nos parâmetros respiratórios c) correlacionar hipertensão pulmonar com presença de incoordenação do MTA. MÉTODOS: o padrão respiratório e o MTA de pacientes com doença mitral foram avaliados por pletismografia respiratória por indutância, nas posições dorsal e sentada, durante dois minutos de respiração tranquila. Analisou-se volume corrente (Vc) e tempos respiratórios e as variáveis do MTA. RESULTADOS: de 65 pacientes incluídos, 10 foram retirados, 29 participaram do grupo estenose mitral e 26 do grupo insuficiência mitral. O Vc, a ventilação pulmonar e o fluxo inspiratório médio aumentaram significantemente na posição sentada, sem diferenças entre os grupos. O MTA manteve-se coordenado entre os grupos e as posições; no entanto, cinco pacientes na posição dorsal apresentaram incoordenação (três no grupo estenose mitral; dois no grupo insuficiência mitral) com correlação significante com valores de pressão de artéria pulmonar (r = 0,992, p = 0,007). CONCLUSÃO: o padrão respiratório e o MTA não apresentam diferenças entre pacientes com estenose ou insuficiência mitral. A posição sentada aumenta o Vc sem alterar os tempos respiratórios. A presença de incoordenação toracoabdominal na posição dorsal esteve associação à hipertensão pulmonar.

Burnt sugarcane harvesting: cardiovascular effects on a group of healthy workers, Brazil

Background: Brazil is the world's largest producer of sugarcane. Harvest is predominantly manual, exposing workers to health risks: intense physical exertion, heat, pollutants from sugarcane burning. Design: Panel study to evaluate the effects of burnt sugarcane harvesting on blood markers and on cardiovascular system. Methods: Twenty-eight healthy male workers, living in the countryside of Brazil were submitted to blood markers, blood pressure, heart rate variability, cardiopulmonary exercise testing, sympathetic nerve activity evaluation and forearm blood flow measures (venous occlusion plethysmography) during burnt sugarcane harvesting and four months later while they performed other activities in sugar cane culture. Results: Mean participant age was 31 +/- 6.3 years, and had worked for 9.8 +/- 8.4 years on sugarcane work. Work during the harvest period was associated with higher serum levels of Creatine Kinase - 136.5 U/L (IQR: 108.5-216.0) vs. 104.5 U/L (IQR: 77.5-170.5), (p = 0.001); plasma Malondialdehyde-7.5 +/- 1.4 mu M/dl vs. 6.9 +/- 1.0 mu M/dl, (p = 0.058); Glutathione Peroxidase - 55.1 +/- 11.8 Ug/Hb vs. 39.5 +/- 9.5 Ug/Hb, (p < 0.001); Glutathione Transferase- 3.4 +/- 1.3 Ug/Hb vs. 3.0 +/- 1.3 Ug/Hb, (p = 0.001); and 24-hour systolic blood pressure - 120.1 +/- 10.3 mmHg vs. 117.0 +/- 10.0 mmHg, (p = 0.034). In cardiopulmonary exercise testing, rest-to-peak diastolic blood pressure increased by 11.12 mmHg and 5.13 mmHg in the harvest and non-harvest period, respectively. A 10 miliseconds reduction in rMSSD and a 10 burst/min increase in sympathetic nerve activity were associated to 2.2 and 1.8 mmHg rises in systolic arterial pressure, respectively. Conclusion: Work in burnt sugarcane harvesting was associated with changes in blood markers and higher blood pressure, which may be related to autonomic imbalance.

Diaphragmatic Breathing Training Program Improves Abdominal Motion During Natural Breathing in Patients With Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

Yamaguti WP, Claudino RC, Neto AP, Chammas MC, Gomes AC, Salge TM, Moriya HT, Cukier A, Carvalho CR. Diaphragmatic breathing training program improves abdominal motion during natural breathing in patients with chronic obstructive pulmonary disease: a randomized controlled trial. Arch Phys Med Rehabil 2012;93:571-7. Objective: To investigate the effects of a diaphragmatic breathing training program (DBTP) on thoracoabdominal motion and functional capacity in patients with chronic obstructive pulmonary disease. Design: A prospective, randomized controlled trial. Setting: Academic medical center. Participants: Subjects (N=30; forced expiratory volume in Is, 4270 +/- 13% predicted) were randomly allocated to either a training group (TG) or a control group (CG). Interventions: Subjects in the TG completed a 4-week supervised DBTP (3 individualized weekly sessions), while those in the CG received their usual care. Main Outcome Measures: Effectiveness was assessed by amplitude of the rib cage to abdominal motion ratio (RC/ABD ratio) (primary outcome) and diaphragmatic mobility (secondary outcome). The RC/ABD ratio was measured using respiratory inductive plethysmography during voluntary diaphragmatic breathing and natural breathing. Diaphragmatic mobility was measured by ultrasonography. A 6-minute walk test and health-related quality of life were also evaluated. Results: Immediately after the 4-week DBTP, the TG showed a greater abdominal motion during natural breathing quantified by a reduction in the RC/ABD ratio when compared with the CG (F=8.66; P<.001). Abdominal motion during voluntary diaphragmatic breathing after the intervention was also greater in the TG than in the CG (F=4.11; P<.05). The TG showed greater diaphragmatic mobility after the 4-week DBTP than did the CG (F=15.08; P<.001). An improvement in the 6-minute walk test and in health-related quality of life was also observed in the TG. Conclusions: DBTP for patients with chronic obstructive pulmonary disease induced increased diaphragm participation during natural breathing, resulting in an improvement in functional capacity.

Influence of high-heeled shoes on venous function in young women

Background: Walking with high-heeled shoes is a common cause of venous complaints such as pain, fatigue, and heavy-feeling legs. The aim of the study was to clarify the influence of high-heeled shoes on the venous return and test the hypothesis that women wearing different styles of high-heeled shoes present an impaired venous return when compared with their values when they are barefoot. Methods: Thirty asymptomatic women (mean age, 26.4 years) wearing appropriately sized shoes were evaluated by air plethysmography (APG), a test that measures changes in air volume on a cuff placed on the calf, while they performed orthostatic flexion and extension foot movements and altered standing up and lying down. The test was repeated in four situations: barefoot (0 cm), medium heels (3.5 cm), stiletto high heels (7 cm), and platform high heels (7 cm). The APG values of venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF) were divided into four groups according to heel height and compared by repeated-measures analysis of variance. Results: RVF was increased in the groups wearing high heels (stiletto and platform) compared with the barefoot group (P < .05). RVF was increased in the medium-heel group (3.5 cm) compared with the barefoot group (P < .05), and despite the lack of statistical significance, the medium-heel group showed lower values of RVF compared with the two high-heel groups. The EF parameter followed the opposite tendency, showing higher values for the barefoot group compared with the other three groups (P < .05). Values for VFI were similar in the three situations evaluated. Conclusions: High heels reduce muscle pump function, as demonstrated by reduced EF and increased RVF values. The continuous use of high heels tends to provoke venous hypertension in the lower limbs and may represent a causal factor of venous disease symptoms. (J Vasc Surg 2012;56:1039-44.)

A high-fat meal impairs muscle vasodilatation response to mental stress in humans with Glu27 β2-adrenoceptor polymorphism

Abstract Background Forearm blood flow responses during mental stress are greater in individuals homozygous for the Glu27 allele. A high-fat meal is associated with impaired endothelium-dependent dilatation. We investigated the impact of high-fat ingestion on the muscle vasodilatory responses during mental stress in individuals with the Glu27 allele and those with the Gln27 allele of the β2-adrenoceptor gene. Methods A total of 162 preselected individuals were genotyped for the Glu27Gln β2-adrenoceptor polymorphism. Twenty-four individuals participated in the study. Fourteen were homozygous for the Gln27 allele (Gln27Gln, 40 ± 2 years; 64 ± 2 kg), and 10 were homozygous for the Glu27 allele (Glu27Glu, 40 ± 3 years; 65 ± 3 kg). Forearm blood flow was evaluated by venous occlusion plethysmography before and after ingestion of 62 g of fat. Results The high-fat meal caused no changes in baseline forearm vascular conductance (FVC, 2.2 ± 0.1 vs. 2.4 ± 0.2; P = 0.27, respectively), but reduced FVC responses to mental stress (1.5 ± 0.2 vs. 0.8 ± 0.2 units; P = 0.04). When volunteers were divided according to their genotypes, baseline FVC was not different between groups (Glu27Glu = 2.4 ± 0.1 vs. Gln27Gln = 2.1 ± 0.1 units; P = 0.08), but it was significantly greater in Glu27Glu individuals during mental stress (1.9 ± 0.4 vs. 1.0 ± 0.3 units; P = 0.04). High-fat intake eliminated the difference in FVC responses between Glu27Glu and Gln27Gln individuals (FVC, 1.3 ± 0.4 vs. 1.2 ± 0.4; P = 0.66, respectively). Conclusion These findings demonstrate that a high-fat meal impairs muscle vasodilatation responses to mental stress in humans. However, this reduction can be attributed to the presence of the homozygous Glu27 allele of the β2-adrenoceptor gene.

Estado nutricional e consumo alimentar de pacientes com psoríase dos tipos sistêmica e artropática sistêmica associada

OBJECTIVE: To identify the nutritional status and food intake of individuals with systemic psoriasis and psoriatic arthritis associated. METHODS: This is an exploratory and cross-sectional study with 34 men aged between 19 and 60 years seen at a Psoriasis Center. Participants were divided into systemic psoriasis group and arthritic-systemic psoriasis associated group. For nutritional assessment we used anthropometry, bioelectrical impedance analysis and whole-body plethysmography. Clinical and nutritional information were assessed using the clinical and nutritional history-taking, and the 24-hour dietary recall. For statistics the general linear model test (p < 0.05) was used. RESULTS: According to the body mass index 29.4% patients (n = 10) were eutrophic, 41.2% (n = 14) overweight and 29% (n = 10) obese. Almost all individuals (60%; n = 21) had body fat percentage above normal levels (> 25%) and a high risk for metabolic complications according to the waist circumference and the obesity index, however, there were no statistically significant differences between groups. The mean food intake, total fat, calories and protein were above recommended levels, being 58.8% for lipids (319.17 ± 241.02 mg of cholesterol and 17.42 ± 11.4 g saturated fatty acids); 29.4% for calories and 67.6% for proteins. Thus, regardless of the psoriasis type, an excessive consumption of calories, lipids, fatty acids, cholesterol and a higher incidence of overweight were found. CONCLUSION: The sample showed an abnormal nutritional condition, an increased risk for chronic diseases related to obesity, worsening of the psoriatic lesions, and poor quality of life.

Protonterapia nel trattamento del tumore prostatico

Obiettivo: Il nostro obiettivo è stato quello di confrontare la tomoterapia (HT) e la protonterapia ad intensità modulata (IMPT) nel trattamento del tumore prostatico, seguendo un protocollo di boost simultaneo (SIB) e moderatamente ipofrazionato. Materiali e metodi: Abbiamo selezionato 8 pazienti, trattati con HT e abbiamo rielaborato i piani con 2 campi IMPT. La dose prescritta è stata di 74 Gy sul PTV1 (prostata e vescicole seminali prossimali), 65.8 Gy sul PTV2 (vescicole seminali distali) e 54 Gy sul PTV3 (linfonodi pelvici). Risultati: Sia con IMPT che con HT abbiamo ottenuto una copertura e una omogeneità di dose del target sovrapponibile. Oltre i 65 Gy, HT e IMPT erano equivalenti per il retto, mentre con l’IMPT c’era maggior risparmio della vescica e del bulbo penieno da 0 a 70 Gy. Da 0 fino a 60 Gy, i valori dosimetrici dell’IMPT erano molto più bassi per tutti gli organi a rischio (OARs), eccetto che per le teste femorali, dove la HT aveva un vantaggio dosimetrico rispetto all’IMPT nel range di dose 25-35 Gy. La dose media agli OARs era ridotta del 30-50% con l’IMPT. Conclusioni: Con le due tecniche di trattamento (HT e IMPT) si ottiene una simile distribuzione di dose nel target. Un chiaro vantaggio dosimetrico dell’IMPT sul HT è ottenuto dalle medie e basse dosi. Le attuali conoscenze sulle relazioni dose-effetto e sul risparmio delle madie e basse dosi con l’IMPT non sono ancora state quantificate dal punto di vista clinico.

Evaluation des effets de l’extrait aqueux des fleurs de Nymphaea lotus Linn. (Nymphéacées) sur la fonction de reproduction des rats normoglycémique et diabétique de type 1

In traditional medicine of Cameroon, Nymphaea lotus Linn. (Nympheaceae) is used for treatment of male sexual disorders. The aim of this study was to evaluate the effects of the N. lotus flowers aqueous extracts on general mating behavior, fertility and some androgenic parameters of normoglycemic and diabetic adult male rats. Mating behavior assessment was carried out with primiparous and with oestrus female rats. Male rats were divided into 5 groups and subjected once in a day to the following treatment: distilled water (10 mL/kg), Sildenafil citrate (5mg/kg), Testosterone enanthate (5mg/kg) and plant extract (75 mg/kg and 150 mg/kg). Treatment lasted for 8 and 55 days before sacrifice. Organ weight, epididymal sperm counts, motility, viability, histomorphometric analysis, muscular strength, seminal fructose, cholesterol level, epididymal and serum proteins testicular were determined. Results showed a dose- dependant influence of the treatment in sperm count and motility which significantly increases compared to the distilled water-administered control. An increase in some sexual performance parameters (mount and intromission frequencies) was observed in both diabetic and normal rats compared to respective controls. The latencies of mount and intromission were significantly reduced. Computed frequencies of penile licking, index of libido and sexual motivation were higher in normal and diabetic extract-treated animals; which suggest an enhancement of motivational parameters. The treatment also caused significant increases in the weight of the testis, prostate, epididymis, in serum cholesterol and epididymal protein level in normal rats compared to the distilled water-administered control. These results indicate an androgenic pro-sexual potential of N. lotus in male rats and justify the empirical use of N. lotus in the management of erectile dysfunction and fertility disorders in males. Key-words: Nymphaea lotus, prosexual, androgenic, fertility, diabetic, male rat. //Selon les tradipraticiens de l’Ouest-Cameroun, Nymphaea lotus Linn. (N. lotus), de la famille des Nymphéacées, est utilisé pour le traitement des dysfonctionnements sexuels chez les hommes. Dans cette étude, l’effet de l’extrait aqueux des fleurs de N. lotus sur la fonction de reproduction des rats mâles adultes normaux et diabétiques a été évalué. Dans le but d’évaluer les effets de l’extrait aqueux des fleurs de N. lotus sur les paramètres généraux de copulation, d’androgénicité et de fertilité, les rats normoglycémiques et diabétiques ont été divisé en 3 groupes contrôle [Groupe I- recevant de l’eau distillée, Groupe II et III recevant respectivement du citrate de sildénafil (5 mg/kg) et l’énanthate de testostérone (5 mg/kg)] et deux groupes expérimentaux traités à l’extrait aux doses 75 mg/kg (Groupe IV) et 150 mg/kg (Groupe V). L’eau distillée, l’extrait et la substance de référence était administré per os une fois par jour. Pour analyser le comportement sexuel et la fertilité, des femelles primipares et en oestrus étaient utilisées. Le traitement a duré 8 et 55 jours avant le sacrifice. Le poids relatif des organes, le nombre de spermatozoïde, la motilité, les analyses morphométriques, la force musculaire, le taux de cholestérol, le taux de protéines sériques et épididymaires étaient déterminé. Le temps de latence de monte et d’intromission a diminué significativement alors que la fréquence d’éjaculation a augmenté. L’index de libido, la fréquence de monte, d’intromission, d’éjaculation, d’orientation des mâles vis-à-vis d’eux même et l’index de motivation sexuelle a augmenté chez les animaux traités l’extrait comparés à ceux ayant reçu de l’eau distillée aussi bien chez les normaux que chez le diabétiques qui n’enregistrent d’ailleurs aucune éjaculation. Le traitement a augmenté significativement (P < 0,01) le poids des testicules, de la prostate et de l’épididyme. Il est observé une augmentation dose-dépendante du nombre et de la motilité des spermatozoïdes (P < 0,05), ainsi qu’une augmentation significative (P < 0,001) temps-dépendant du taux de cholestérol sérique et de protéines épididymaires. Ces résultats indiquent un potentiel androgénique pro-érectile de N. lotus chez les rats mâles et justifient l’utilisation empirique des fleurs de N. lotus dans le traitement des dysfonctions érectiles et des problèmes de fertilité chez les hommes. Mots-clés: Nymphaea lotus, pro-érectile, androgénique, fertilité, diabétiques, rat male

Urogenital manifestations in Wegener granulomatosis: a study of 11 cases and review of the literature

We describe the main characteristics and treatment of urogenital manifestations in patients with Wegener granulomatosis (WG). We conducted a retrospective review of the charts of 11 patients with WG. All patients were men, and their median age at WG diagnosis was 53 years (range, 21-70 yr). Urogenital involvement was present at onset of WG in 9 cases (81%), it was the first clinical evidence of WG in 2 cases (18%), and was a symptom of WG relapse in 6 cases (54%). Symptomatic urogenital involvement included prostatitis (n = 4) (with suspicion of an abscess in 1 case), orchitis (n = 4), epididymitis (n = 1), a renal pseudotumor (n = 2), ureteral stenosis (n = 1), and penile ulceration (n = 1). Urogenital symptoms rapidly resolved after therapy with glucocorticoids and immunosuppressive agents. Several patients underwent a surgical procedure, either at the time of diagnosis (n = 3) (consisting of an open nephrectomy and radical prostatectomy for suspicion of carcinoma, suprapubic cystostomy for acute urinary retention), or during follow-up (n = 3) (consisting of ureteral double J stents for ureteral stenosis, and prostate transurethral resection because of dysuria). After a mean follow-up of 56 months, urogenital relapse occurred in 4 patients (36%). Urogenital involvement can be the first clinical evidence of WG. Some presentations, such as a renal or prostate mass that mimics cancer or an abscess, should be assessed to avoid unnecessary radical surgery. Urogenital symptoms can be promptly resolved with glucocorticoids and immunosuppressive agents. However, surgical procedures, such as prostatic transurethral resection, may be mandatory in patients with persistent symptoms.

Periodic breathing during ascent to extreme altitude quantified by spectral analysis of the respiratory volume signal

High altitude periodic breathing (PB) shares some common pathophysiologic aspects with sleep apnea, Cheyne-Stokes respiration and PB in heart failure patients. Methods that allow quantifying instabilities of respiratory control provide valuable insights in physiologic mechanisms and help to identify therapeutic targets. Under the hypothesis that high altitude PB appears even during physical activity and can be identified in comparison to visual analysis in conditions of low SNR, this study aims to identify PB by characterizing the respiratory pattern through the respiratory volume signal. A number of spectral parameters are extracted from the power spectral density (PSD) of the volume signal, derived from respiratory inductive plethysmography and evaluated through a linear discriminant analysis. A dataset of 34 healthy mountaineers ascending to Mt. Muztagh Ata, China (7,546 m) visually labeled as PB and non periodic breathing (nPB) is analyzed. All climbing periods within all the ascents are considered (total climbing periods: 371 nPB and 40 PB). The best crossvalidated result classifying PB and nPB is obtained with Pm (power of the modulation frequency band) and R (ratio between modulation and respiration power) with an accuracy of 80.3% and area under the receiver operating characteristic curve of 84.5%. Comparing the subjects from 1(st) and 2(nd) ascents (at the same altitudes but the latter more acclimatized) the effect of acclimatization is evaluated. SaO(2) and periodic breathing cycles significantly increased with acclimatization (p-value < 0.05). Higher Pm and higher respiratory frequencies are observed at lower SaO(2), through a significant negative correlation (p-value < 0.01). Higher Pm is observed at climbing periods visually labeled as PB with > 5 periodic breathing cycles through a significant positive correlation (p-value < 0.01). Our data demonstrate that quantification of the respiratory volume signal using spectral analysis is suitable to identify effects of hypobaric hypoxia on control of breathing.

Noninvasive monitoring of chest wall movement in infants using laser

Traditionally, non-invasive monitoring of tidal volume in infants has been performed using impedance plethysmography analyzed using a one or two compartment model. We developed a new laser system for use in infants, which measures antero-posterior movement of the chest wall during quiet sleep. In 24 unsedated or sedated infants (11 healthy, 13 with respiratory disease), we examined whether the analysis of thoracoabdominal movement based on a three compartment model could more accurately estimate tidal volume in comparison to V(T) measured at the mouth. Using five laser signals, chest wall movements were measured at the right and left, upper and lower ribcage and the abdomen. Within the tidal volume range from 4.6 to 135.7 ml, a three compartment model showed good short term repeatability and the best agreement with tidal volume measured at mouth (r(2) = 0.86) compared to that of a single compartment model (r(2) = 0.62, P < 0.0001) and a two compartment model (r(2) = 0.82, P < 0.01), particularly in the presence of respiratory disease. Three compartment modeling of a 5 laser thoracoabdominal monitoring permits more accurate estimates of tidal volume in infants and potentially of regional differences of chest wall displacement in future studies.

Helium breathing provides modest antiinflammatory, but no endothelial protection against ischemia-reperfusion injury in humans in vivo

BACKGROUND: The noble gas helium is devoid of anesthetic effects, and it elicits cardiac preconditioning. We hypothesized that inhalation of helium provides protection against postocclusive endothelial dysfunction after ischemia-reperfusion of the forearm in humans. METHODS: Eight healthy male subjects were enrolled in this study with a crossover design. Each volunteer was randomly exposed to 15 min of forearm ischemia in the presence or absence of helium inhalation. Helium was inhaled at an end-tidal concentration of 50 vol% from 15 min before ischemia until 5 min after the onset of reperfusion ("helium conditioning"). Hyperemic reaction, a marker of nitric oxide bioavailability and endothelial function, was determined at 15 and 30 min of reperfusion on the forearm using venous occlusion plethysmography. Expression of the proinflammatory markers CD11b, ICAM-1, PSGL-1, and L-selectin (CD62L) on leukocytes and P-selectin (CD62P), PSGL-1, and CD42b on platelets were measured by flow cytometry during reperfusion. RESULTS: Ischemia-reperfusion consistently reduced the postocclusive endothelium-dependent hyperemic reaction at 15 and 30 min of reperfusion. Periischemic inhalation of helium at 50 vol% did not improve postocclusive hyperemic reaction. Helium decreased expression of the proinflammatory marker CD11b and ICAM-1 on leukocytes and attenuated the expression of the procoagulant markers CD42b and PSGL-1 on platelets. CONCLUSIONS: Although inhalation of helium diminished the postischemic inflammatory reaction, our data indicate that human endothelium, which is a component of all vital organs, is not amenable to protection by helium at 50 vol% in vivo. This is in contrast to sevoflurane, which protects human endothelium at low subanesthetic concentrations.