The present series of unmanned hyperbaric tests were conducted in order to investigate the oxygen fraction variability in semi-closed underwater rebreathing apparatuses. The tested rebreathers were RB80 (Halcyon dive systems, High springs, FL, USA), IS-Mix (Interspiro AB, Stockholm, Sweden), CRABE (Aqua Lung, Carros Cedex, France), and Viper+ (Cobham plc, Davenport, IA, USA). The tests were conducted using a catalytically based propene combusting metabolic simulator. The metabolic simulator connected to a breathing simulator, both placed inside a hyperbaric pressure chamber, was first tested to demonstrate its usefulness to simulate human respiration in a hyperbaric situation. Following this the metabolic simulator was shown to be a useful tool in accident investigations as well as to assess the impact of different engineering designs and physiological variables on the oxygen content in the gas delivered to the diver by the rebreathing apparatuses. A multi-compartment model of the oxygen fractions was developed and compared to the previously published single-compartment models. The root mean squared error (RMSE) of the multi-compartment model was smaller than the RMSE for the single-compartment model, showing its usefulness to estimate the impact of different designs and physiological variables on the inspired oxygen fraction. / <p>QC 20150903</p>

Das Rett Syndrom (RTT) gehört zu den tiefgreifenden Entwicklungsstörungen des Gehirns von dem fast ausschließlich Mädchen betroffen sind (ICD-10, F84.10). Ursächlich für die Pathogenese sind Mutationen im X-chromsomalen MECP2-Gen, welches für den Transkriptionsfaktor Methyl-CpG binding protein 2 (MeCP2) kodiert. Unterschiedliche neurologische Symptome treten zwischen 6 und 18 Monaten nach der Geburt auf, wobei schwere Rhythmussstörungen der Atmung für ein Viertel plötzlicher Todesfälle bei Rett-Patientinnen verantwortlich gemacht werden. Der neuronale Atmungsrhythmus bei Säugern wird in verschieden Regionen des ponto-medullären Hirnstammes generiert, wobei der Prä-Bötzinger Komplex als essentiell für die Rhythmogenese der Atmung angesehen wird. Mittels Genexpressionsstudien in der Ventralen Respiratorischen Gruppe (VRG), die den Prä-Bötzinger-Komplex einschließt, zeigte sich eine massiv erhöhte, pathologische Expression des Serotoninrezeptor 5B sowohl auf mRNA-, als auch auf Proteinebene bei MeCP2-defizienten Mäusen zum postnatalen Entwicklungstag P40. Der Serotoninrezeptor 5B (5-HTR5B) gehört zur Klasse der G-Protein-gekoppelten Rezeptoren. Durch detaillierte Analysen des 5-HTR5B-Proteins konnte eine natürliche Trunkierung des Rezeptors nachgewiesen werden. Des Weiteren wurde eine ungewöhnliche intrazelluläre Lokalisierung in Membranen von vesikulären und tubulären Kompartimenten beobachtet. Trotz dieser ungewöhnlichen Eigenschaften besitzt der Rezeptor weiterhin die Fähigkeit, das inhibitorische G-Protein Gαi3 konstitutiv zu aktivieren und somit den Anstieg von cAMP zu verhindern. Durch genetisches Ausschalten des 5-HTR5B Proteins (knockout) konnte gezeigt werden, dass die durch 5-HTR5B-verminderte cAMP-Konzentration in der VRG ursächlich für den gestörten Atmungsrhythmus MeCP2-defizienter Mäuse ist. Die sich aus diesen Ergebnissen ableitende pharmakologische Strategie, die cAMP Konzentration zu erhöhen, führte zu einem deutlich verbesserten Atmungsrhythmus. Die Ergebnisse dieser Arbeit implizieren neue Therapieansätze zur Behandlung der Atmungs-störungen von Rett-Patienten.

This study examined the effects of temperature and chronic hypoxia (CH) on pH/CO2- sensitive fictive breathing, and central pH/CO2 chemosensitivity, in cane toads (Bufo marinus). Toads were exposed to CH (10% or 15% O2) or control conditions (21% O2) for 10 days at either room temperature (controls), 10°C or 30°C following which in vitro brainstem-spinal cord preparations were used to examine central pH/CO2-sensitive fictive breathing (i.e., motor output from respiratory nerves which is the neural correlate of breathing). A reduction in artificial cerebral spinal fluid (aCSF) pH increased fictive breathing frequency (fR) and total fictive ventilation (TFV). Cold temperature reduced and hot temperature increased fR and TFV under control conditions. CH attenuated fictive breathing independently of temperature. Additional experiments in which the aCSF temperature was varied indicate that the effects of temperature acclimation result from neural plastic changes within respiratory control centres in the brain.

Rebirthing – is form of american pranayoga. Also breathing is one of most principal yoga aspects, which removes physical and emotional blocks in the cellular level of all human body. Rebirthing is called also, conscious connected breathing, live or intuitive breathwork. The main object of rebirthing is to disperse daily stress. It’s also used as a therapeutic healing method, which person can practice and this way to learn sense of fresh energy. Urgency of reserach was stipulate by reason, that rebirthing was not investigate in Lithuania until now, although came here in revival period, on 1991. consequently this scientific work is the first rebirthing research in Lithuania. The object of research is to investigate subjectival estimated emotional wealth changes of people, which are practicing rebirthing. It was promoted hypothesis of research, that person regulary practicing conscious connected breathing, can achieve reduce of chained feelings, express emotions. This practice attaches rest and relaxation. The tasks of research: 1. To analyse, rebirthing conception by theoretical aspect. 2. To establish subjectical estimated feelings and emotions from outset of rebirthing practice. 3. To reveal subjectical estimated emotional wealth changes. The realized researches established, that majority of engaged into research get over suppressed anxiety, fear and weeping. ... [to full text]

Tyrimo naujumas ir aktualumas: Atlikta mokslinių tyrimų analizė rodo, kad kvėpavimo sistemos reguliacijos pokyčių asmenims, su lėtiniais nugaros smegenų pažeidimais (LNSP) tyrimai išlieka aktualūs iki šiol. Kol kas nėra pilnai aišku, kaip kvėpavimo funkcijos mechanizmai, tarpšonkaulinių įkvėpimo ir iš kvėpimo raumenų bei diafragmos veikla, o taip pat bronchų spindis kinta ir sąveikauja tarpusavyje, priklausomai nuo nugaros smegenų įvairaus lygmens pažeidimo poveikyje atsiradusių krūtinės ląstos ir pilvo raumenų paralyžiaus, nes kompleksinių tyrimų nebuvo atlikta. Taip pat neaišku, kaip šie mechanizmai kinta, ar jų pokytis gali limituoti kvėpavimo funkciją keičiant kūno padėtį, ypač į ortostatinę, kas būtų labai svarbu nustatyti siekiant tyrimo duomenis pritaikyti neįgaliųjų sporto medicinoje. Literatūros duomenys rodo, kad asmenims su LNSP (lėtiniais nugaros smegenų pažeidimais) kvėpavimo funkcija silpnėja, lyginant su įgaliais asmenimis, kad ji gali priklausyti nuo nefiziologinės diafragmos padėties, susidariusios dėl šonkaulių kampo pokyčių, esant pilvo raumenų paralyžiui, kad esant LNSP gali keistis kvėpavimo takų spindis, kaip konpensacinis mechanizmas sumažėjus išorinio kvėpavimo funkcijai (Alvarez et al, 1981; Baydur et al, 2001; Mueller et al, 2006). Tačiau tokių tyrimų buvo atlikta labai nedaug, ir, kaip jau minėta, kompleksinių tyrimų, apjungiančių šiuos mechanizmus, iš viso neradome. Kvėpavimo funkcijos tyrimai įvairiose kūno padėtyse (gulint, ortostatinėje ir... [toliau žr. visą tekstą] / The novelty of the research: The investigations show that analyses of the respiratory changes of people with spinal cord injuries are still relevant. However, it is still unknown how pathological mechanisms interact with each other depending to the level of spinal cord injury because no complex investigations were carried out. Also, it is unknown how these mechanisms vary depending on the body position. Whether they limit the physical activity in the sport of disable people in order to prevent complications in the respiratory system or whether physical activities can reduce the influence of the pathological mechanisms to the respiratory system in this way improve it. These questions are very important in the medicine of the disable sport. Such investigations are not carried out with the people with spinal cord injuries. Previous researches show that peope with spinal cord injuries have weal respiratory function comparing with able people (Mueller et al, 2006). It can be depended on the non physiological position of the diaphragm which is formed due to the changes of the rib angle with paralysis of the abdomen muscle. Also, in the condition with spinal cord injuries the transience of the airways can be changed as compensation mechanism for the reduced function of the external respiratory. However, there are very few researches carried out and as it was mentioned previously, no integrated researches were carried out which involve these mechanisms. The analysis of the... [to full text]

Acid-base regulation, as reflected by hydrogen ion concentration ([H+]), and the chemoreflex control of breathing were examined in healthy pre- (PRE; n=20) and postmenopausal (POST; n=15) women of a comparable age (45 ± 2.7 vs. 52 ± 1.8 years). [H+] behaviour was examined in both groups at rest and during exercise above the ventilatory threshold using Stewart’s physicochemical approach to acid-base analysis. Ventilatory chemoreflex characteristics were assessed using Duffin’s modified rebreathing protocol that includes 5 min of prior hyperventilation and maintenance of either hyperoxic (150 mmHg) or hypoxic (50 mmHg) iso-oxia. As expected, the ovarian hormones progesterone ([P4]) and estrogen ([E2]) were significantly lower in the POST group. [H+] was unaffected by menopausal status at rest or during exercise. At rest the POST group exhibited significantly higher PaCO2 and [SID] values relative to the PRE group. In general, the acidifying effects of increased PaCO2 were offset by the alkalizing effect of increases in [SID] (or vice versa) in the POST group such that [H+] did not differ between PRE and POST groups. The central ventilatory chemoreflex also differed between groups with the POST group exhibiting a significantly higher threshold and a lower sensitivity in the response to CO2 relative to the PRE group. [P4] was found to partially account for the significant group differences in acid-base and central ventilatory chemoreflex control characteristics supporting the role of [P4] as an important determinant of acid-base status and the chemical control of ventilation in healthy women. Findings of the current study may have potential relevance in understanding the increased occurrence of various health conditions such as osteoporosis and sleep disordered breathing in females following the onset of menopause. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2007-09-21 08:53:00.841

Human pregnancy is characterized by significant increases in central ventilatory drive and perceived respiratory discomfort (breathlessness). The physiological mechanisms of hyperventilation and breathlessness in pregnancy remain largely unknown and understudied. Objective: The main purpose of this research was to elucidate the mechanisms of maternal hyperventilation, and to systematically examine the contribution of alterations in central ventilatory drive, static/dynamic respiratory mechanics and their interaction with respect to the intensity of perceived breathlessness during exercise in pregnancy. General Methods: Experiments were conducted between 34-38 wks gestation and again 4-5 months post-partum in a total of 35 healthy, young women. A comprehensive mathematical model of ventilatory control was used to examine the role of alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance and female sex hormones in maternal hyperventilation. The effects of pregnancy on detailed ventilatory (breathing pattern, airway function, operating lung volumes, esophageal pressure-derived indices of respiratory mechanics) and perceptual (breathing and leg discomfort) responses to incremental cycle exercise to the limits of tolerance were also examined. Results: Maternal hyperventilation resulted from a complex interaction between alterations in arterial and central acid-base balance and other factors that directly affect ventilation, including increased wakefulness and central chemoreflex drives to breathe, increased metabolism and decreased cerebral blood flow. Mechanical adaptations of the respiratory system, including recruitment of resting inspiratory capacity and reduced airway resistance, accommodated the increased demand for tidal volume expansion during exercise in pregnancy, while preserving effort-displacement and breathlessness-ventilation relationships. Variation in the severity of gestational breathlessness could not be explained by respiratory mechanical/muscular factors, but ultimately reflected variation in the amplitude of maternal hyperventilation and temporal desensitization to the sensory consequences of increased ventilation. Conclusion: Our results indicated that 1) the hyperventilation and attendant hypocapnia/alkalosis of pregnancy can be explained by alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance, metabolic rate and cerebral blood flow; 2) mechanical adaptations of the respiratory system obviated the anticipated rise in perceived breathlessness for a given ventilation during exercise in pregnancy, and helped to ensure that peak aerobic working capacity was admirably preserved, even in late gestation; and 3) gestational breathlessness ultimately reflected the normal awareness of increased ventilation and contractile respiratory muscle effort. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2008-08-28 16:01:40.78

Evidence suggests that slow paced diaphragmatic breathing (DB) can significantly affect prefrontal cortex functions through increasing an individual’s physiological self-regulatory capacity. The current research demonstrates the effects of paced DB on inhibitory control, which is considered to be a reliable measure of behavioral self-regulation. Eighty healthy participants were randomly assigned to one of two conditions (20 males and females each). Participants were instructed on either DB at a pace of six-breaths per minute (BPM) or instructions on environmental awareness and asked to breathe at 12 BPM. Following training, all participants completed a computer-based task designed to examine inhibitory processes. Physiological recordings of heart rate (HR), BPM, and HRV were collected at baseline, during the breathing training, during the cued go/no-go task, and after the cued go/no-go task. The findings demonstrated that the DB condition had significantly lower BPM, HR, and higher HRV (p’s<0.05) during active training than the environmental awareness condition. Furthermore, the DB condition performed significantly better on the measure of inhibition than the environmental awareness condition (p<0.05). The use of DB as a reliable method to increase physiological self-regulatory capacity and improve behavioral self-regulation, measured as inhibitory control, should continue to be explored.

Mitral Valve Prolapse Syndrome (MVPS) is a benign psychosomatic cardiac condition that can severely impair one's quality of life. Symptoms targeted in this study include, atypical chest pain, palpitations, anxiety, panic, and shortness of breath.This study was undertaken to examine the effects of a diaphragmatic breathing intervention on the symptoms and underlying mechanism of dysautonomia in a small group of symptomatic females with MVPS. The intervention was based on both yoga theory and cardiorespiratory empirical studies.Seven of eight participant's completed the nine week study using a single subject multiple baseline design across subjects. Participant's began a respiratory retraining intervention, in a weekly staggered pair start, after the first week of baseline measurement. Respiratory training consisted of a four week training in diaphragmatic breathing with home practice three times a day.Autonomic, behavioral, and cognitive systems were assessed. Dependent measures included State and Trait Anxiety, Anxiety Sensitivity, a Symptom Checklist, and Respiratory Sinus Arrhythmia (RSA). RSA is a current noninvasive measure of parasympathetic tone. Data on thoracic and abdominal respiratory predominance, respiration rate, diet, exercise, and adherence were also gathered.Data were analyzed via visual inspection of trends and phase average changes. Treatment effect sizes were calculated for standardized measures to indicate the meaningfulness of change.Two of the seven participants demonstrated a decrease in total symptom frequencies over the course of intervention. One participant demonstrated a weekly progression of lowered state anxiety scores from baseline through intervention. In terms of phase averages, three participants showed a lowering of state anxiety. All seven participants demonstrated lowered trait anxiety scores from pre to post intervention. Two of the seven participants demonstrated a meaningful pre to post intervention decrease in anxiety sensitivity. Respiratory training was effective in stabilizing abdominal respiration. Results regarding vagal tone could not be determined due to unreliable ECG data.In general, results were poor with several inconsistencies. Adherence rates were low and it did not appear that a therapeutic level of change in respiration rate was achieved. Controlling respiration rate may be a critical factor in the therapeutic effectiveness of respiratory retraining interventions. / Department of Counseling Psychology and Guidance Services

In radiation therapy, a treatment plan is designed to make the delivery of radiation to a target more accurate, effective, and less damaging to surrounding healthy tissues. In lung sites, the tumor is affected by the patient’s respiratory motion. Despite tumor motion, current practice still uses a static delivery plan. Unexpected changes due to coughs and sneezes are not taken into account and as a result, the tumor is not treated accurately and healthy tissues are damaged. In this thesis we detail a framework of using an accelerometer device to detect and forecast coughs. The accelerometer measurements are modeled as a ARMA process to make forecasts. We draw from studies in cough physiology and use amplitudes and durations of the forecasted breathing cycles as features to estimate parameters of Gaussian Mixture Models for cough and normal breathing classes. The system was tested on 10 volunteers, where each data set consisted of one 3-5 minute accelerometer measurements to train the system, and two 1-3 minute accelerometer measurements for testing.