Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Eur J Appl Physiol ; 124(6): 1693-1702, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38189825

RESUMO

PURPOSE: Dive-induced cardiac and hemodynamic changes are caused by various mechanisms, and they are aggravated by cold water. Therefore, aging divers with pre-existing cardiovascular conditions may be at risk of acute myocardial infarction, heart failure, or arrhythmias while diving. The aim of this study was to assess the effect of a single decompression CCR dive in arctic cold water on cardiac function in Finnish technical divers. METHODS: Thirty-nine divers performed one identical 45 mfw CCR dive in 2-4 °C water. Hydration and cardiac functions were assessed before and after the dive. Detection of venous gas embolization was performed within 120 min after the dive. RESULTS: The divers were affected by both cold-water-induced hemodynamic changes and immersion-related fluid loss. Both systolic and diastolic functions were impaired after the dive although the changes in cardiac functions were subtle. Venous inert gas bubbles were detected in all divers except for one. Venous gas embolism did not affect systolic or diastolic function. CONCLUSION: A single trimix CCR dive in arctic cold water seemed to debilitate both systolic and diastolic function. Although the changes were subtle, they appeared parallel over several parameters. This indicates a real post-dive deterioration in cardiac function instead of only volume-dependent changes. These changes are without a clinical significance in healthy divers. However, in a population with pre-existing or underlying heart problems, such changes may provoke symptomatic problems during or after the dive.


Assuntos
Temperatura Baixa , Descompressão , Mergulho , Humanos , Mergulho/fisiologia , Masculino , Adulto , Pessoa de Meia-Idade , Descompressão/métodos , Feminino , Coração/fisiologia , Coração/fisiopatologia , Hemodinâmica/fisiologia
2.
Mil Med ; 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37878799

RESUMO

INTRODUCTION: Finnish military divers perform a great variety of tasks all year round, all of which require good physical health and fitness. Poor physical fitness can hinder the ability to cope with different situations. A high body fat percentage has been suggested to increase the risk of decompression sickness, whereas low muscle mass has been associated with an increased risk of musculoskeletal disorders and trauma. However, a low-fat composition may render divers vulnerable to cold and hypothermia during a dive in cold Arctic conditions. The aim of this study was to evaluate possible changes in body composition of Finnish military divers during a 15-year follow-up period (2007-2021). MATERIALS AND METHODS: We used body composition measures from military divers' fit-to-dive evaluations from the Finnish Defence Forces' Diving Medical Centre. Measurements were taken with two bioimpedance devices that function based on the electrical conductivity properties of the human body. The data from both devices were compared with Bland-Altman plots to show that the devices produced congruent data and the results from both devices could be included in the study. Possible changes in body composition were evaluated with a linear mixed model with random intercepts and slopes for each variable. RESULTS: Results from the two bioimpedance devices showed no significant differences. This allowed us to combine the results in the same data analysis. There were no apparent differences in the age of the divers between the years during the follow-up. The majority of the divers were between 25 and 30 years of age. Age correlated significantly with most measures, the clinically most significant being a higher fat percentage in older divers. However, all measures were within target values defined by the Diving Medical Centre. The divers were able to retain sufficient muscle mass in all age groups. DISCUSSION AND CONCLUSIONS: According to this study, Finnish military divers have managed to maintain a surprisingly good muscle mass in all age groups despite body composition changes due to aging in older subjects. A slight increase in fat mass can be observed with increasing age; nevertheless, the values have remained within fit-to-dive target levels. The current training routines of Finnish military divers are adequate for maintaining solid physical fitness and body composition over the course of the diving career.

3.
Clin Physiol Funct Imaging ; 43(4): 291-296, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36757012

RESUMO

INTRODUCTION AND METHODS: There is limited knowledge of cumulative effect of repetitive cold-water diving on cardiac function. Single cold dives cause some known cardiological risks, such as malign arrhythmia, due to a concurrent activation of the sympathetic and parasympathetic autonomic nervous system. A previous study from warmer water dives has shown that successive dives cause a decrease in vagal tone and a less responsive cardiovascular system. The aim of this study was to evaluate changes in cardiac function with 2D echocardiography during 4 days of diving in near-freezing water. RESULTS: Left ventricle systolic function measures did not show any uniform changes. E/A ratio seemed to decrease successively with the number of dives. The diastolic tissue velocity of relaxing basal septum (e') showed a decreasing trend as well. Diastolic blood pressure seemed to increase from predive (mean: 83 RR mmHg) to postdive values (mean: 87 RR mmHg) (p=NS). Heart rate decreased significantly from predive (mean: 71 bpm, range: 56-103) to postdive values (mean: 60 bpm, range: 37-88) (p < 0.03). DISCUSSION AND CONCLUSIONS: The study was conducted in very cold condition and with limited number of divers. Results of this preliminary study suggested a decreasing trend in left ventricular diastolic function in successive cold dives. Cumulative changes in cardiac function may cause health risks that need to be considered during cold water diving operations.


Assuntos
Mergulho , Humanos , Mergulho/efeitos adversos , Mergulho/fisiologia , Pressão Sanguínea/fisiologia , Função Ventricular Esquerda , Ecocardiografia , Água
4.
Physiol Rep ; 10(4): e15153, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35212176

RESUMO

Navy divers tend to have large lungs and low expiratory flow rates in the terminal portion of a spirogram. We examined Finnish Navy divers for the presence of air trapping, airway obstruction, and functional airway compression, and their association with lung volumes. Divers (n = 57) and non-diving men (n = 10) underwent a variety of pulmonary function tests. The amount of trapped air was calculated as the subtraction of the total lung capacity (TLC) measured in a single-breath helium dilution test from the TLC in body plethysmography (TLCb). Mean vital capacity (VC) was 6.4 L in the divers versus 5.8 L in the controls (p = 0.006) and TLCb 8.9 L in the divers versus 8.1 L in the controls (p = 0.002). No difference existed between them in the amount of trapped air. However, we found break points in a linear regression model (Davies test) between trapped air and several pulmonary parameters. Those individuals above the break points had lower ratio of forced expiratory volume in first second to forced vital capacity, lower resistance of airways, and higher reactance than those below the break points. In conclusion, navy divers had larger lungs than controls. Large lung volumes (VC >7.31 L or >122% of predicted value) were associated with air trapping. Furthermore, large volumes of air trapping (>1.1 L) were associated with increased residual volume (RV) and RV/TLCb. Despite no concurrent obstruction, functional airway compression, or reduced diffusing capacity, this slowly ventilated trapped air might remain disadvantageous for divers.


Assuntos
Pulmão , Volume Expiratório Forçado , Humanos , Masculino , Testes de Função Respiratória , Capacidade Pulmonar Total , Capacidade Vital
5.
Undersea Hyperb Med ; 46(4): 429-435, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31509899

RESUMO

INTRODUCTION: It is vital to protect divers from the cold, particularly in Arctic conditions. The insulating gas layer within the drysuit is crucial for reducing heat loss. The technical diving community has long claimed the superiority of argon over air as an insulating gas. Although argon is widely used, previous studies have shown no significant differences between the two gases. Owing to its lower heat conductivity, argon should be a better thermal insulating gas than air. METHODS: The study aimed to determine whether argon is beneficial for reducing heat loss in divers during development of military drysuit diving equipment in Arctic water temperatures. Four divers completed 14 dives, each lasting 45 minutes: seven dives used air insulation and seven used argon insulation. Rectal and eight skin temperatures were measured from which changes in calculated mean body temperature (MBT) were assessed. RESULTS: There was a significant reduction in area weighted skin temperature over time (0-45 minute) on air dives (ΔTskin = -4.16°C, SE = 0.445, P ⟨ 0.001). On argon dives the reduction was significantly smaller compared to air dives (difference between groups = 2.26°C, SE = 0.358, P ⟨ 0.001). There were no significant changes in rectal temperatures, nor was a significant difference seen between groups. CONCLUSION: Compared to air, argon may be superior as a drysuit insulating gas in Arctic water temperatures for some divers. Argon used as insulating gas can make diving safer and may diminish the risks of fatal diving accidents and occupational hazard risks in professional diving.


Assuntos
Ar , Argônio , Mergulho , Roupa de Proteção , Temperatura Cutânea , Condutividade Térmica , Adulto , Regiões Árticas , Regulação da Temperatura Corporal , Temperatura Baixa , Desenho de Equipamento/métodos , Finlândia , Humanos , Masculino , Pessoa de Meia-Idade , Militares , Estudos Retrospectivos
6.
Front Physiol ; 10: 1600, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32082177

RESUMO

INTRODUCTION: Diving close to the Arctic circle means diving in cold water regardless of the time of year. The human body reacts to cold through autonomous nervous system (ANS)-mediated thermoregulatory mechanisms. Diving also induces ANS responses as a result of the diving reflex. MATERIALS AND METHODS: In order to study ANS responses during diving in Arctic water temperatures, we retrospectively analyzed repeated 5-min heart rate variability (HRV) measures and the mean body temperature from dives at regular intervals using naval diving equipment measurement tests in 0°C water. Three divers performed seven dives without physical activity (81-91 min), and two divers performed four dives with physical activity after 10 min of diving (0-10 min HRV recordings were included in the study). RESULTS: Our study showed a significant increase in parasympathetic activity (PNS) at the beginning of the dives, after which PNS activity decreased significantly (measure 5-10 min). Subsequent measurements (15-20 min and onward) showed a significant increase in PNS activity over time. CONCLUSION: Our results suggest that the first PNS responses of the human diving reflex decrease quickly. Adverse effects of PNS activity should be considered on long and cold dives. To avoid concurrent sympathetic (SNS) and PNS activity at the beginning of dives, which in turn may increase the risk of arrhythmia in cold water, we suggest a short adaptation phase before physical activity. Moreover, we suggest it is prudent to give special attention to cardiovascular risk factors during pre-dive examinations for cold water divers.

7.
Front Neurol ; 7: 82, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27303362

RESUMO

INTRODUCTION: Glycogen storage disease V (GSDV, McArdle disease) and GSDVII (Tarui disease) are the most common of the rare disorders of glycogen metabolism. Both are associated with low lactate levels on exercise. Our aim was to find out whether lactate response associated with exercise testing could distinguish between these disorders. METHODS: Two siblings with Tarui disease, two patients with McArdle disease and eight healthy controls were tested on spiroergometric exercise tests with follow-up of venous lactate and ammonia. RESULTS: A late increase of lactate about three times the basal level was seen 10-30 min after exercise in patients with Tarui disease being higher than in McArdle disease and lower than in the controls. Ammonia was increased in Tarui disease. DISCUSSION: Our results suggest that follow-up of lactate associated with exercise testing can be utilized in diagnostics to distinguish between different GSD diseases.

8.
Diving Hyperb Med ; 46(2): 82-6, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27334995

RESUMO

INTRODUCTION: Inert gas narcosis (IGN) impairs cognitive performance and some divers are more susceptible to IGN than others. We compared the sensitivity of two reaction time tests to detect changes in performance at pressure and compared these results with critical flicker fusion frequency (CFF) changes at the same ambient pressures. METHODS: The study assessed simple reaction time (RT), mean time correct of the discrimination reaction time (MTC) and CFF in 30 professional divers breathing air at 101 kPa and 608 kPa in a hyperbaric chamber. RESULTS: RT and MTC increased at 608 kPa by 5.1 ± 9.4% (P = 0.04) and 7.3 ± 12.3% (P = 0.01) respectively. RT decreased to pre-compression level after decompression and MTC decreased to a level lower than pre-compression (P < 0.001) values. CFF increased by 2.5 ± 2.8% (P < 0.001) at 608 kPa. CFF decreased to pre-compression level after decompression. An increase in CFF was inversely correlated with a decrease in RT (r = 0.38, P = 0.04) and in MTC (r = 0.43, P = 0.02) at 608 kPa. CONCLUSIONS: Response speeds of the same subjects were impaired in both reaction time tasks at 608 kPa, whereas CFF increased at depth. An association between changes in response times and changes in CFF suggests that divers susceptible to IGN may also be susceptible to the effects of elevated oxygen partial pressure. If this holds true, the future selection of professional divers could be improved by the use of simple cognitive tests.


Assuntos
Mergulho/fisiologia , Fusão Flicker/fisiologia , Pressão , Tempo de Reação/fisiologia , Adulto , Pressão Atmosférica , Suscetibilidade a Doenças/diagnóstico , Humanos , Narcose por Gás Inerte/etiologia , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia , Água do Mar , Adulto Jovem
9.
BMC Pulm Med ; 14: 34, 2014 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-24593176

RESUMO

BACKGROUND: Dynamic gas compression during forced expiration has an influence on conventional flow-volume spirometry results. The extent of gas compression in different pulmonary disorders remains obscure. Utilizing a flow plethysmograph we determined the difference between thoracic and mouth flows during forced expiration as an indication of thoracic gas compression in subjects with different pulmonary diseases characterized by limitations in pulmonary mechanics. METHODS: Patients with emphysema (N = 16), interstitial lung disease (ILD) (N = 15), obesity (N = 15) and healthy controls (N = 16) were included. Compressed expiratory flow-volume curves (at mouth) and corresponding compression-free curves (thoracic) were recorded. Peak flow (PEF) and maximal flows at 75%, 50% and 25% of remaining forced vital capacity (MEF75, MEF50 and MEF25) were derived from both recordings. Their respective difference was assessed as an indicator of gas compression. RESULTS: In all groups, significant differences between thoracic and mouth flows were found at MEF50 (p < 0.01). In controls, a significant difference was also measured at MEF75 (p <0.005), in emphysema subjects, at PEF and MEF75 (p < 0.05, p < 0.005) and in obese subjects at MEF75 (p <0.005) and MEF25 (p < 0.01). ILD patients showed the lowest difference between thoracic and mouth flows at MEF75 relative to controls and emphysema patients (p < 0.005, p < 0.001). Obese subjects did not differ from controls, however, the difference between thoracic and mouth flows was significantly higher than in patients with emphysema at MEF50 (p < 0.001) and MEF25 (p < 0.005). CONCLUSIONS: Alveolar gas compression distorts the forced expiratory flow volume curve in all studied groups at the middle fraction of forced expiratory flow. Consequently, mouth flows are underestimated and the reduction of flow measured at 75% and 50% of vital capacity is often considerable. However, gas compression profiles in stiff lungs, in patients with decreased elastic recoil in emphysema and in obesity differ; the difference between thoracic and mouth flows in forced expiration was minimal in ILD at the first part of forced expiration and was higher in obesity than in emphysema at the middle and last parts of forced expiration.


Assuntos
Expiração , Doenças Pulmonares Intersticiais/fisiopatologia , Obesidade/fisiopatologia , Enfisema Pulmonar/fisiopatologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Função Respiratória
10.
Vaccine ; 23(46-47): 5328-32, 2005 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-16118028

RESUMO

Finnish and Israeli infants received an 11-valent mixed carrier pneumococcal conjugate vaccine (11PCV) with or without aluminum adjuvant at the age of 2, 4, 6, and 12 months. We measured opsonophagocytic activity (OPA) of antibodies to pneumococcal strains of serotypes 4, 6B, 14, 19F, and 23F. At 7 months, OPA was clearly detected for all the serotypes. At 13 months, OPAs increased further and the proportion of individuals with a positive OPA ranged between 81 and 100%. The adjuvant improved functional activity of antibodies to serotype 6B pneumococci. In conclusion, immunization of infants with the 11PCV induced functionally active antibodies.


Assuntos
Anticorpos Antibacterianos/imunologia , Vacinas Pneumocócicas/imunologia , Adjuvantes Imunológicos/farmacologia , Hidróxido de Alumínio/farmacologia , Anticorpos Antibacterianos/análise , Afinidade de Anticorpos , Finlândia , Humanos , Imunidade Celular/imunologia , Esquemas de Imunização , Técnicas Imunoenzimáticas , Imunoglobulina G/imunologia , Lactente , Recém-Nascido , Israel , Proteínas Opsonizantes , Fagocitose/imunologia , Polissacarídeos/imunologia , Vacinas Conjugadas/imunologia
11.
Pediatr Infect Dis J ; 23(2): 91-8, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14872172

RESUMO

BACKGROUND: To have wide global coverage of pneumococcal serotypes, the number of serotypes covered by the current 7-valent pneumococcal conjugate vaccine must be increased. We have studied the safety and immunogenicity of an 11-valent mixed carrier vaccine (PncDT11) in infants. METHODS: The study vaccine contained polysaccharide antigens of serotypes 1, 4, 5, 7F, 9V, 19F and 23F conjugated to tetanus protein and serotypes 3, 6B, 14 and 18C conjugated to diphtheria toxoid. The vaccine was administered to Finnish (n = 117) and Israeli (n = 135) infants at ages 2, 4, 6 and 12 months concomitantly with other vaccines used in national vaccination programs. IgG antibodies to polysaccharides were determined by enzyme immunoassay from serum samples taken at ages 2, 7, 12 and 13 months. After each injection the infants were followed for 30 min to detect any immediate adverse reactions, and parents were given a diary card to report any adverse events during the next 5 days. RESULTS: No severe adverse reactions occurred, and immediate adverse reactions were rare. After each dose approximately 30% of the vaccinees experienced local reactions of which pain was the most common. Fever of >38 degrees C was reported in 33 to 53% of the vaccinees and high fever (>40 degrees C) was reported 6 times. The PncDT11 vaccine was immunogenic. The antibody concentrations after primary immunization series were higher in Israeli than in Finnish infants, but the differences were not significant for most serotypes. The difference was most marked at 13 months, a time point at which the difference was significant in 10 of 11 serotypes. CONCLUSION: PncDT11 is safe and immunogenic in infants. The use of 11-valent pneumococcal vaccine would increase the serotype coverage beyond the currently available 7-valent vaccine.


Assuntos
Portador Sadio/prevenção & controle , Vacina contra Difteria e Tétano/administração & dosagem , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/administração & dosagem , Polissacarídeos Bacterianos/administração & dosagem , Vacinação/métodos , Anticorpos Antibacterianos/análise , Cápsulas Bacterianas/imunologia , Ensaios Clínicos Fase II como Assunto , Intervalos de Confiança , Feminino , Finlândia , Humanos , Imunidade/fisiologia , Imunização Secundária , Lactente , Israel , Masculino , Infecções Pneumocócicas/imunologia , Polissacarídeos Bacterianos/imunologia , Probabilidade , Testes Sorológicos , Streptococcus pneumoniae/imunologia , Vacinas Conjugadas/administração & dosagem
12.
Infect Immun ; 71(12): 6844-9, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14638771

RESUMO

NspA is a conserved membrane protein that elicits protective antibody responses in mice against Neisseria meningitidis. A recent crystallographic study showed that NspA adopts an eight-stranded beta-barrel structure when reconstituted in detergent. In order to define the segments of NspA-containing epitopes recognized by protective murine anti-NspA antibodies, we studied the binding of two bactericidal and protective anti-NspA monoclonal antibodies (MAbs), AL12 and 14C7. Neither MAb binds to overlapping synthetic peptides (10-mers, 12-mers, and cyclic 12-mers) corresponding to the entire mature sequence of NspA, or to denatured recombinant NspA (rNspA), although binding to the protein can be restored by refolding in liposomes. Based on the ability of the two MAbs to bind to Escherichia coli microvesicles prepared from a set of rNspA variants created by site-specific mutagenesis, the most important contacts between the MAbs and NspA appear to be located within the LGG segment of loop 3. The conformation of loop 2 also appears to be an important determinant, as particular combinations of residues in this segment resulted in loss of antibody binding. Thus, the two anti-NspA MAbs recognize discontinuous conformational epitopes that result from the close proximity of loops 2 and 3 in the three-dimensional structure of NspA. The data suggest that optimally immunogenic vaccines using rNspA will require formulations that permit proper folding of the protein.


Assuntos
Anticorpos Monoclonais/imunologia , Proteínas da Membrana Bacteriana Externa/química , Epitopos/imunologia , Neisseria meningitidis/imunologia , Conformação Proteica , Sequência de Aminoácidos , Animais , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/imunologia , Humanos , Lipossomos , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Dobramento de Proteína , Ratos , Proteínas Recombinantes
13.
Pediatr Infect Dis J ; 22(2): 141-9, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12586978

RESUMO

BACKGROUND: Antibody responses to pneumococcal conjugate vaccines may vary when administered in different populations or epidemiologic settings. Understanding the causes and significance of this variation could help to determine the number of doses and timing required for protection against pneumococcal diseases in each country. METHODS: This report compares antibody responses to aluminum-adjuvanted and nonadjuvanted mixed carrier 11-valent diphtheria- or tetanus-conjugated pneumococcal vaccine (11-PncTD) formulations when given at 6, 10 and 14 weeks and 9 months of age to Filipino infants (n = 51) and at 2, 4, 6 and 12 months of age to Finnish (n = 127) and Israeli (n = 124) infants. The study populations differ in their natural exposure to pneumococcus and risk factors for pneumococcal carriage and disease. RESULTS: Filipino and Israeli infants had slightly but significantly higher prevaccination geometric mean concentration (GMC) of antibodies than did the Finnish infants. After three doses of aluminum-adjuvanted 11-PncTD vaccine, the Filipino infants had 1.8 to 6.7 and 1.5 to 5.0 times higher GMC than the Finnish and Israeli infants, respectively, against pneumococcal serotypes conjugated to tetanus protein. The GMC of serotypes conjugated to diphtheria toxoid was 1.3 to 3.0 and 0.7 to 2.0 times the GMC in Finnish and Israeli infants, respectively. The nonadjuvanted vaccine formulation induced generally lower GMCs. CONCLUSIONS: The antibody responses to the tetanus-conjugated polysaccharides were considerably higher in the Filipino than in the Finnish or Israeli infants. This may be a result of several factors including the priming effect of tetanus toxoid given to pregnant women, early pneumococcal nasopharyngeal acquisition and genetic differences among populations.


Assuntos
Anticorpos Antibacterianos/imunologia , Portador Sadio/imunologia , Vacina contra Difteria e Tétano/imunologia , Difteria/imunologia , Infecções Pneumocócicas/imunologia , Vacinas Pneumocócicas/imunologia , Tétano/imunologia , Formação de Anticorpos/imunologia , Difteria/prevenção & controle , Vacina contra Difteria e Tétano/administração & dosagem , Relação Dose-Resposta a Droga , Ensaio de Imunoadsorção Enzimática , Feminino , Finlândia , Humanos , Esquemas de Imunização , Lactente , Israel , Masculino , Filipinas , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/administração & dosagem , Sensibilidade e Especificidade , Tétano/prevenção & controle , Vacinação/métodos , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA