RESUMO
The aim of our study was to determine whether the immunohistochemical expression of placental vitamin D receptors is altered in pregnancies complicated by preeclampsia. Vitamin D receptor expression was immunohistochemically analysed in the placentas of three groups: a control group, and early- and late-onset preeclampsia groups. Total immunohistochemical intensity staining of placentas showed that the control group had a median vitamin D receptor (VDR) expression significantly higher than the placentas of mothers with early- and late-onset preeclampsia. There was no difference among the three groups in a semiquantitative analysis of VDR staining of the stroma only. Vitamin D receptors showed lower median expression in preeclampsia-affected pregnancies, especially early-onset preeclampsia. Therefore, Vitamin D receptor expression may be an important marker for normal placentation and preeclampsia onset.
Assuntos
Placenta , Pré-Eclâmpsia , Humanos , Gravidez , Feminino , Receptores de CalcitriolRESUMO
Women with polycystic ovary syndrome seem to have a larger ovarian reserve. However, regardless of a greater reserve, diminished ovarian reserve has been reported after laparoscopic diathermy. The aim of this article was to determine whether the doses adjusted unilateral laparoscopic ovarian drilling with diathermy (ULOD) diminishes ovarian reserve to compare with bilateral laparoscopic ovarian drilling with diathermy (BLOD). Ninety-six women were assigned in two groups. One group underwent ULOD receiving thermal doses (0-840 J per ovary) adjusted to volume one ovary. The other group underwent BLOD receiving fixed doses (600 J per ovary). Ovarian reserve markers [anti-Müllerian hormone (AMH); antral follicle count (AFC) and ovarian volume] were measured before and after surgery (1 and 6 months). Both groups showed a decrease in AMH after surgery, but it was significantly more distinct in the BLOD versus ULOD group (2.0 ng/mL versus 1.3 ng/mL; p = 0.018) in the first follow-up month and remained significantly different through the sixth follow-up month (1.9 ng/mL versus 1.15 ng/mL; p = 0.023). In contrast, in the sixth month, the ULOD versus BLOD showed a significantly greater increase AFC (p < 0.001) and volume (p = 0.013). Our findings evidenced that the dose-adjusted unilateral diathermy (60 J/cm(3)) does not have significant and long-term effects on ovarian reserve.
Assuntos
Hormônio Antimülleriano/sangue , Diatermia/métodos , Folículo Ovariano/fisiopatologia , Reserva Ovariana/fisiologia , Síndrome do Ovário Policístico/fisiopatologia , Adulto , Feminino , Humanos , Estudos Longitudinais , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/cirurgia , Resultado do TratamentoRESUMO
Ovarian torsions in adolescence are rarity, particularly bilateral, with mostly unknown etiology. Enlargement of the ovary contributes to torsion. Young girl presenting with abdominal pains, nausea and vomiting was for two days suspected and observed as gastroenteritis. By exclusion of gastroenteritis she was admitted for gynecological work-up. Ultrasound showed significantly enlarged right ovary, with tumor-like appearance. At the laparotomy, gynecologist found torsioned, necrotic ovary and ovariectomy was performed. Histology showed massive stromal bleeding (haemorrhage). Asymptomatic enlargement of remaining ovary occurred nine months after the ovariectomy. This enlargement was accompanied with platelets' fall and the possibility of repeated torsion impended. Thrombocytopenia was suspected from the first moment, but diagnosed after the surgery. Thrombocytopenia in adolescence requires additional attention as possible cause of intra-ovarian bleeding with consecutive enlargement and may lead to torsion. Oral contraceptives regulate dysfunctional bleeding, decrease ovarian volume and by so, may minimize risk of torsion. This strategy proved effective in the case we present.
Assuntos
Doenças Ovarianas/diagnóstico , Doenças Ovarianas/etiologia , Púrpura Trombocitopênica Idiopática/complicações , Anormalidade Torcional/diagnóstico , Anormalidade Torcional/etiologia , Adolescente , Doença Crônica , Feminino , Humanos , Doenças Ovarianas/cirurgia , Ovariectomia , Anormalidade Torcional/cirurgiaRESUMO
A prospective observational study (ClinicalTrial ID: NCT05771415) was conducted to compare placental oxygenation in low-risk, uncomplicated term pregnancies measured by near-infrared spectroscopy (NIRS) in relation to the placental maturity grade determined by ultrasound assessment according to the Grannum scale. We included 34 pregnancies divided into two groups according to placental maturation. For each pregnancy, measurements were taken at the site above the central part of the placenta (test) and at the site outside of the placenta on the lower abdomen (control). Student's t-test was used to compare tissue oxygenation index (TOI) values among the study groups. The normality of distribution was proven by the KolmogorovâSmirnov test. In women with low placental maturity grade, the mean TOI value above the placenta was 70.38 ± 3.72, which was lower than the respective value in women with high placental maturity grade (77.99 ± 3.71; p < 0.001). The TOI values above the placenta and the control site were significantly different in both groups (70.38 ± 3.72 vs 67.83 ± 3.21 and 77.99 ± 3.71 vs 69.41 ± 3.93; p < 0.001). The results offer a new perspective on placental function based on specific non-invasive real-time oxygenation measurements. Unfortunately, and because of technical limitations, NIRS cannot yet be implemented as a routine clinical tool.
RESUMO
Apnea divers increase intrathoracic pressure voluntarily by taking a deep breath followed by glossopharyngeal insufflation. Because apnea divers sometimes experience hypotension and syncope during the maneuver, they may serve as a model to study the mechanisms of syncope. We recorded changes in hemodynamics and sympathetic vasomotor tone with microneurography during breath holding with glossopharyngeal insufflation. Five men became hypotensive and fainted during breath holding with glossopharyngeal insufflation within the first minute. In four divers, heart rate dropped suddenly to a minimum of 38 ± 4 beats/min. Therefore, cardioinhibitory syncope was more common than low cardiac output syncope.
Assuntos
Apneia/fisiopatologia , Mergulho/fisiologia , Nervo Glossofaríngeo/fisiologia , Insuflação , Síncope/fisiopatologia , Adulto , Débito Cardíaco/fisiologia , Cardiografia de Impedância , Eletrocardiografia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Hipotensão/etiologia , Hipotensão/fisiopatologia , Masculino , Oxigênio/sangue , Volume Sistólico/fisiologia , Fibras Simpáticas Pós-Ganglionares/fisiologiaRESUMO
1. The spleen contains approximately one-third of all the body's platelets. These platelets are relatively larger and haemostatically more active than platelets in the systemic circulation and can be released into the systemic circulation by stimulation of alpha-adrenoceptors or inhibition of beta-adrenoceptors. In the present study, we evaluated the effects of selective (bisoprol) and non-selective (carvedilol) beta-blockers agents on mean platelet volume (MPV) and spleen size in hypertensive patients at rest and after exercise. 2. Blood pressure, heart rate, platelet count, MPV and spleen volume were measured in 18 newly diagnosed hypertensive patients, as well as in nine healthy control subjects, subjected to treadmill exercise test at their first visit and, for the hypertensive group, after 15 and 30 days of treatment with the selective beta(1)-adrenoceptor antagonist bisoprolol 5 mg/day (n = 9) or the non-selective alpha(1)-, beta(1)- and beta(2)-adrenoceptor antagonist carvedilol 25 mg/day (n = 9). 3. Increases in resting MPV values with concomitant decreases in spleen volume were found after 15 and 30 days treatment with either bisoprolol or carvedilol. The pronounced decrease in splenic volume after exercise and the increased MPV and platelet counts seen at first visit were halved after 15 and 30 days of treatment with either drug. 4. We conclude that in hypertensive patients treated with either selective or non-selective beta-blockers, the spleen contracts and MPV increases, which may increase the risk of atherothrombosis.
Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Plaquetas/efeitos dos fármacos , Hipertensão/patologia , Baço/efeitos dos fármacos , Antagonistas Adrenérgicos beta/uso terapêutico , Adulto , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Bisoprolol/farmacologia , Bisoprolol/uso terapêutico , Plaquetas/patologia , Carbazóis/farmacologia , Carbazóis/uso terapêutico , Carvedilol , Tamanho Celular/efeitos dos fármacos , Exercício Físico/fisiologia , Teste de Esforço , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Humanos , Hipertensão/sangue , Hipertensão/tratamento farmacológico , Hipertensão/fisiopatologia , Pessoa de Meia-Idade , Tamanho do Órgão/efeitos dos fármacos , Propanolaminas/farmacologia , Propanolaminas/uso terapêutico , Descanso/fisiologia , Baço/patologia , Especificidade por SubstratoRESUMO
Repeated hypoxemia in obstructive sleep apnea patients increases sympathetic activity, thereby promoting arterial hypertension. Elite breath-holding divers are exposed to similar apneic episodes and hypoxemia. We hypothesized that trained divers would have increased resting sympathetic activity and blood pressure, as well as an excessive sympathetic nervous system response to hypercapnia. We recruited 11 experienced divers and 9 control subjects. During the diving season preceding the study, divers participated in 7.3 +/- 1.2 diving fish-catching competitions and 76.4 +/- 14.6 apnea training sessions with the last apnea 3-5 days before testing. We monitored beat-by-beat blood pressure, heart rate, femoral artery blood flow, respiration, end-tidal CO(2), and muscle sympathetic nerve activity (MSNA). After a baseline period, subjects began to rebreathe a hyperoxic gas mixture to raise end-tidal CO(2) to 60 Torr. Baseline MSNA frequency was 31 +/- 11 bursts/min in divers and 33 +/- 13 bursts/min in control subjects. Total MSNA activity was 1.8 +/- 1.5 AU/min in divers and 1.8 +/- 1.3 AU/min in control subjects. Arterial oxygen saturation did not change during rebreathing, whereas end-tidal CO(2) increased continuously. The slope of the hypercapnic ventilatory and MSNA response was similar in both groups. We conclude that repeated bouts of hypoxemia in elite, healthy breath-holding divers do not lead to sustained sympathetic activation or arterial hypertension. Repeated episodes of hypoxemia may not be sufficient to drive an increase in resting sympathetic activity in the absence of additional comorbidities.
Assuntos
Células Quimiorreceptoras/fisiopatologia , Mergulho , Hipercapnia/fisiopatologia , Hipóxia/fisiopatologia , Inalação , Músculo Esquelético/inervação , Centro Respiratório/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Adulto , Apneia/fisiopatologia , Velocidade do Fluxo Sanguíneo , Pressão Sanguínea , Dióxido de Carbono/sangue , Artéria Femoral/fisiopatologia , Frequência Cardíaca , Humanos , Hipercapnia/sangue , Hiperóxia/fisiopatologia , Hipóxia/sangue , Masculino , Vias Neurais/fisiopatologia , Oxigênio/sangue , Ventilação Pulmonar , Fluxo Sanguíneo Regional , Espirometria , Fatores de TempoRESUMO
The fact that impaired endothelial-dependent vasodilatation after scuba diving often occurs without visible changes in the endothelial layer implies its biochemical origin. Since Lewisx(CD15) and sialyl-Lewisx(CD15s) are granulocyte and monocyte carbohydrate antigens recognized as ligands by endothelial selectins, we assumed that they could be sensitive markers for impaired vasodilatation following diving. Using flow cytometry, we determined the CD15 and CD15s peripheral blood mononuclear cells of eight divers, 30 mins before and 50 mins after a single dive to 54 m for 20 mins bottom time. The number of gas bubbles in the right heart was monitored by ultrasound. Gas bubbles were seen in all eight divers, with the average number of bubbles/cm2 1.9+/-1.9. The proportion of CD15+monocytes increased 2-fold after the dive as well as the subpopulation of monocytes highly expressing CD15s. The absolute number of monocytes was slightly, but not significantly, increased after the dive, whereas the absolute number of granulocytes was markedly elevated (up to 61%). There were no significant correlations between bubble formation and CD15+monocyte expression (r=-0.56; P=0.17), as well as with monocytes highly expressing CD15s (r=0.43; P=0.29). This study suggests that biochemical changes induced by scuba diving primarily activate existing monocytes rather than increase the number of monocytes at a time of acute arterial endothelial dysfunction.
Assuntos
Mergulho/fisiologia , Células Endoteliais/metabolismo , Leucócitos/metabolismo , Selectinas/metabolismo , Adulto , Humanos , Antígenos CD15/metabolismo , LigantesRESUMO
Involuntary breathing movements (IBM) that occur in the struggle phase of maximal apneas produce waves of negative intrathoracic pressure. This could augment the venous return, increasing thereby the cardiac output and gas exchange, and release the fresh blood from venous pools of spleen and liver. To test these hypotheses we used photoplethysmography and ultrasound for assessment of hemodynamics and spleen size before, during and after maximal dry apneas at large lung volume in 7 trained divers. During the easy-going phase cardiac output was reduced about 40%, due to reduction in stroke volume and in presence of reduced inferior vena cava venous return, while the spleen contracted for about 60 ml. Towards the end of the struggle phase, in presence of intense IBM, the spleen volume further decreased for about 70 ml, while cardiac output and caval flow almost renormalized. In conclusion, IBM coincide with splenic volume reduction and restoration of hemodynamics, likely facilitating the use of the last oxygen reserves before apnea cessation.
Assuntos
Adaptação Fisiológica , Débito Cardíaco/fisiologia , Mergulho/fisiologia , Mecânica Respiratória/fisiologia , Adulto , Apneia/fisiopatologia , Fenômenos Fisiológicos Cardiovasculares , Hemodinâmica , Humanos , Masculino , Músculo Liso/fisiologia , Fotopletismografia , Troca Gasosa Pulmonar/fisiologiaRESUMO
INTRODUCTION: Most decompression procedures induce the formation of asymptomatic venous gas bubbles. They can be classified as "silent bubbles," which are asymptomatic compared to paradoxical arterialization of venous gas emboli, which can lead to serious neurologic damage. The penetration of such gas bubbles into the arterial circulation is due to pulmonary barotrauma, intrapulmonary (I-P) passage after massive bubble formation ("chokes"), or intracardiac shunting. Venous gas bubbles can be monitored and graded with echocardiographic scanning. CASE: We believe this is the first case to be reported of a recreational diver who, after surfacing from a dive, developed grade 5 ("white-out") venous gas bubbles in the right heart with evidence of I-P shunt at rest without any symptoms of decompression sickness. Grade 4 gas bubbles were found on the left side of the heart, indicating significant I-P shunting even at rest. CONCLUSION: We observed venous bubbles crossing through the I-P shunt during post-dive recovery at rest in a diver who developed "white out" of venous bubbles. Previously, the maximum bubble grade 5 had been observed in experimental animals, but not in humans. Moreover, a significant bubble grade was found on the left side of the heart, indicating a need for further studies to investigate the mechanisms of post-dive changes in peripheral and central circulation.
Assuntos
Mergulho/fisiologia , Embolia Aérea/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Circulação Pulmonar/fisiologia , Adulto , Doença da Descompressão/fisiopatologia , Ecocardiografia Transesofagiana , Humanos , Masculino , Troca Gasosa Pulmonar/fisiologiaRESUMO
We investigated the spleen volume changes as related to the cardiovascular responses during short-duration apneas at rest. We used dynamic ultrasound splenic imaging and noninvasive photoplethysmographic cardiovascular measurements before, during, and after 15-20 s apneas in seven trained divers. The role of baroreflex was studied by intravenous bolus of vasodilating drug trinitrosan during tidal breathing. The role of lung volume was studied by comparing the apneas at near-maximal lung volume with apneas after inhaling tidal volume, with and without cold forehead stimulation. In apneas at near maximal lung volume, a 20% reduction in splenic volume (P = 0.03) was observed as early as 3 s after the onset of breath holding. Around that time the heart rate increased, the mean arterial pressure abruptly decreased from 89.6 to 66.7 mmHg (P = 0.02), and cardiac output decreased, on account of reduction in stroke volume. Intravenous application of trinitrosan resulted in approximately 6-mmHg decrement in mean arterial pressure, while the splenic volume decreased for approximately 13%. In apneas at low lung volume, the early splenic contraction was also observed, 10% without and 12% with cold forehead stimulation, although the mean arterial pressure did not change or even increased, respectively. In conclusion, the spleen contraction is present at the beginning of apnea, accentuated by cold forehead stimulation. At large, but not small, lung volume, this initial contraction is probably facilitated by downloaded baroreflex in conditions of decreased blood pressure and cardiac output.
Assuntos
Apneia/fisiopatologia , Sistema Cardiovascular/fisiopatologia , Mergulho , Baço/fisiopatologia , Adulto , Apneia/diagnóstico por imagem , Barorreflexo , Pressão Sanguínea , Débito Cardíaco , Sistema Cardiovascular/efeitos dos fármacos , Sistema Cardiovascular/inervação , Temperatura Baixa , Frequência Cardíaca , Humanos , Injeções Intravenosas , Pulmão/fisiopatologia , Medidas de Volume Pulmonar , Nitroglicerina/administração & dosagem , Tamanho do Órgão , Fotopletismografia , Baço/diagnóstico por imagem , Baço/efeitos dos fármacos , Baço/inervação , Artéria Esplênica/diagnóstico por imagem , Artéria Esplênica/fisiopatologia , Fatores de Tempo , Ultrassonografia , Resistência Vascular , Vasodilatadores/administração & dosagemRESUMO
The effects of maximal apneas on cerebral and brachial blood flow and oxygenation are unknown in humans. Middle cerebral artery blood velocity (MCAV), cerebral and muscle oxygenation (Sc(O2) and Sm(O2)) and brachial blood flow (BBF) were measured during apneas in breath-hold divers (BHD) and non-divers (ND). Brain oxyhemoglobin (O(2)Hb) was maintained in both groups until the end of apnea, whereas deoxyhemoglobin increased more in BHD. Therefore, Sc(O2) decreased more in BHD due to longer apnea duration and smaller initial MCAV increase. MCAV increased significantly more in BHD versus ND at the end of apnea. Cerebral desaturation for approximately 13% occurred at the end of apnea in BHD despite increased cerebral oxygen delivery for approximately 50%. Larger reduction in muscle O(2)Hb was found in BHD, with similar peripheral vasoconstriction. These data indicate that BHD have decreased Sc(O2) at the end of breath-hold despite large increases in MCAV. This is partly due delayed initial cerebral vasodilation. This study provides further evidence for the oxygen-conserving effect in elite divers.
Assuntos
Apneia/fisiopatologia , Encéfalo/irrigação sanguínea , Circulação Cerebrovascular , Músculo Esquelético/irrigação sanguínea , Consumo de Oxigênio/fisiologia , Respiração , Adulto , Mergulho/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Artéria Cerebral Média/fisiologia , Oxiemoglobinas/metabolismo , Fluxo Sanguíneo Regional , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Estatísticas não Paramétricas , Ultrassonografia Doppler Transcraniana/métodosRESUMO
INTRODUCTION: We have recently shown that a single air dive leads to acute arterial vasodilation and impairment of endothelium-dependent vasodilatation in humans. Additionally we have found that predive antioxidants at the upper recommended daily allowance partially prevented some of the negative effects of the dive. In this study we prospectively evaluated the effect of long-term antioxidants at a lower RDA dose on arterial endothelial function. METHODS: Eight professional male divers performed an open sea air dive to 30 msw. Brachial artery flow-mediated dilation (FMD) was assessed before and after diving. RESULTS: The first dive, without antioxidants, caused significant brachial arterial diameter increase from 3.85 +/- 0.55 to 4.04 +/- 0.5 mm and a significant reduction of FMD from 7.6 +/- 2.7 to 2.8 +/- 2.1%. The second dive, with antioxidants, showed unchanged arterial diameter and significant reduction of FMD from 8.11 +/- 2.4 to 6.8 +/- 1.4%. The FMD reduction was significantly less with antioxidants. Vascular smooth muscle function, assessed by nitroglycerine (endothelium-independent dilation), was unaffected by diving. DISCUSSION: This study shows that long-term antioxidant treatment at a lower RDA dose ending 3-4 h before a dive reduces the endothelial dysfunction in divers. Since the scuba dive was of a similar depth and duration to those practiced by numerous recreational divers, this study raises the possibility of routine predive supplementation with antioxidants.
Assuntos
Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Mergulho/fisiologia , Vasodilatação/efeitos dos fármacos , Vitamina E/farmacologia , Adulto , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Braquial/diagnóstico por imagem , Artéria Braquial/fisiologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Humanos , Hiperemia/fisiopatologia , Masculino , Músculo Liso Vascular/fisiologia , Nitroglicerina/farmacologia , Estudos Prospectivos , Ultrassonografia , Vasodilatação/fisiologia , Vasodilatadores/farmacologiaRESUMO
Changes in cardiovascular parameters elicited during a maximal breath hold are well described. However, the impact of consecutive maximal breath holds on central hemodynamics in the postapneic period is unknown. Eight trained apnea divers and eight control subjects performed five successive maximal apneas, separated by a 2-min resting interval, with face immersion in cold water. Ultrasound examinations of inferior vena cava (IVC) and the heart were carried out at times 0, 10, 20, 40, and 60 min after the last apnea. The arterial oxygen saturation level and blood pressure, heart rate, and transcutaneous partial pressures of CO(2) and O(2) were monitored continuously. At 20 min after breath holds, IVC diameter increased (27.6 and 16.8% for apnea divers and controls, respectively). Subsequently, pulmonary vascular resistance increased and cardiac output decreased both in apnea divers (62.8 and 21.4%, respectively) and the control group (74.6 and 17.8%, respectively). Cardiac output decrements were due to reductions in stroke volumes in the presence of reduced end-diastolic ventricular volumes. Transcutaneous partial pressure of CO(2) increased in all participants during breath holding, returned to baseline between apneas, but remained slightly elevated during the postdive observation period (approximately 4.5%). Thus increased right ventricular afterload and decreased cardiac output were associated with CO(2) retention and signs of peripheralization of blood volume. These results indicate that repeated apneas may cause prolonged hemodynamic changes after resumption of normal breathing, which may suggest what happens in sleep apnea syndrome.
Assuntos
Dióxido de Carbono/metabolismo , Monóxido de Carbono/metabolismo , Mergulho/fisiologia , Artéria Pulmonar/fisiologia , Volume Sistólico/fisiologia , Veia Cava Inferior/fisiologia , Adaptação Fisiológica/fisiologia , Adulto , Humanos , Masculino , Síndromes da Apneia do Sono/fisiopatologia , Resistência Vascular/fisiologia , Vasodilatação/fisiologiaRESUMO
PURPOSE: Prevention of bubble formation is a central goal in standard decompression procedures. Previously we have shown that exercise 20-24 h prior to a dive reduces bubble formation and increases survival in rats exposed to a simulated dive. Furthermore, we have demonstrated that nitric oxide (NO) may be involved in this protection; blocking the production of NO increases bubble formation while giving rats a long-lasting NO donor 20 h and immediately prior to a dive reduces bubble formation. This study determined whether a short-lasting NO donor, nitroglycerine, reduced bubble formation after standard dives and decompression in man. METHODS: A total of 16 experienced divers were randomly assigned into two groups. One group performed two dives to 30 m of seawater (msw) for 30 min breathing air, and performed exercise at an intensity corresponding to 30% of maximal oxygen uptake during the bottom time. The second group performed two simulated dives to 18 msw for 80 min breathing air in a hyperbaric chamber, and remained sedentary during the bottom period. The first dive for each diver served as the control dive, whereas the divers received 0.4 mg of nitroglycerine by oral spray 30 min before the second dive. Following the dive, gas bubbles in the pulmonary artery were recorded using ultrasound. RESULTS: The open-water dive resulted in significantly more gas bubbles than the dry dive (0.87 +/- 1.3 vs 0.12 +/- 0.23 bubbles per square centimeter). Nitroglycerine reduced bubble formation significantly in both dives from 0.87 +/- 1.3 to 0.32 +/- 0.7 in the in-water dive and from 0.12 +/- 0.23 to 0.03 +/- 0.03 bubbles per square centimeter in the chamber dive. CONCLUSION: The present study demonstrates that intake of a short-lasting NO donor reduces bubble formation following decompression after different dives.
Assuntos
Doença da Descompressão/prevenção & controle , Doença da Descompressão/fisiopatologia , Mergulho/fisiologia , Gases/sangue , Doadores de Óxido Nítrico/administração & dosagem , Nitroglicerina/administração & dosagem , Adulto , Doença da Descompressão/diagnóstico por imagem , Frequência Cardíaca/fisiologia , Humanos , Oxigenoterapia Hiperbárica , Masculino , Consumo de Oxigênio/fisiologia , Artéria Pulmonar/diagnóstico por imagem , UltrassonografiaRESUMO
INTRODUCTION: The effect of post-dive exercise on bubble formation remains controversial, although the current practice of divers and aviators is to avoid strenuous exercise after diving. Previously, we have shown that exercising 24 h before a dive, or during a decompression stop, significantly reduces bubble formation in man. The objective of this study was to determine whether a short period of strenuous post-dive exercise promotes venous bubble formation. METHODS: Seven male military divers performed an open-sea field dive to a maximum depth of 30 m for 30 min. At maximum depth, subjects performed mild underwater fin swimming, followed by standard decompression. Diving was followed by a post-dive exercise session consisting of short, strenuous incremental upright cycle ergometry, up to 85% of maximal oxygen uptake, for about 10 min. Subjects were monitored for venous gas bubbles in the right heart with an echo-imaging system starting 20 min post-dive while in the supine position, during cycle ergometry in the seated upright position, and immediately after exercise in a supine position. RESULTS: The average number of bubbles was 1.5 +/- 1.4 bubbles x cm(-2) 20 min after diving. Changes in posture from supine to seated upright resulted in significant reduction of bubbles to 0.6 +/- 1.3 bubbles x cm(-2) (p = 0.043), with further reduction to 0.2 +/- 0.3 bubbles x cm(-2) at the end of exercise (p = 0.02). No cases of DCS or intra-pulmonary shunt were observed during or following post-dive exercise. DISCUSSION: These results suggest that post-dive strenuous exercise after a single field dive reduces post-dive gas bubble formation in well-trained military divers. Additional findings are needed for normal sports divers.
Assuntos
Doença da Descompressão/prevenção & controle , Mergulho/fisiologia , Exercício Físico/fisiologia , Gases/sangue , Adulto , Humanos , Masculino , Medicina Militar , Estatísticas não Paramétricas , VeiasRESUMO
INTRODUCTION: The human diving reflex is characterized by bradycardia, decreased cardiac output, and peripheral vasoconstriction, and has an oxygen-conserving effect both at rest and during exercise. However, the resultant time course and extent of muscle desaturation is unknown. METHODS: We used near-infrared spectroscopy to continuously measure the decrease in tissue oxygen saturation (StO2) in the calf muscle during a series of breath-holds. Subjects were seven trained divers (TD) and eight untrained controls (UC). Other measured variables included arterial blood pressure, heart rate, and arterial oxygen saturation (SaO2). Each subject performed five maximal apneas during face immersion in cold water with 2-min recovery intervals between breath-holds. RESULTS: On average, total apnea time for TD was significantly longer than for UC (772.6 +/- 40.9 s vs. 499.1 +/- 118.2 s, respectively). Further, TD had a more pronounced decrease in StO2 than UC (70.6 +/- 15.3% for TD vs. 87.9 +/- 6.1% UC for the fifth and longest apnea). When values for the two groups were compared at the mean breakpoint time for UC, there was no difference in StO2 and SaO2 remained at baseline. By contrast, at the same time point in all five apneas, UC experienced simultaneous, significantly larger reductions in SaO2 and StO2. DISCUSSION: These data indicate that TD have an attenuated diving reflex compared with UC at the same breath-hold times (the breakpoint for UC). In addition, muscle desaturation occurs earlier than arterial desaturation in both groups; the fact that this effect was less pronounced in TD suggests a training effect. This study provides further evidence for the oxygen-conserving effect of the human diving reflex in maintaining the oxygen supply of vital organs.
Assuntos
Mergulho/fisiologia , Músculo Esquelético/metabolismo , Consumo de Oxigênio/fisiologia , Respiração , Adulto , Pressão Sanguínea/fisiologia , Face , Frequência Cardíaca/fisiologia , Humanos , Imersão , Perna (Membro) , Masculino , Reflexo/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho , Vasoconstrição/fisiologia , ÁguaRESUMO
Paradoxical arterializations of venous gas emboli can lead to neurological damage after diving with compressed air. Recently, significant exercise-induced intrapulmonary anatomical shunts have been reported in healthy humans that result in widening of alveolar-to-arterial oxygen gradient. The aim of this study was to examine whether intrapulmonary shunts can be found following strenuous exercise after diving and, if so, whether exercise should be avoided during that period. Eleven healthy, military male divers performed an open-sea dive to 30 m breathing air, remaining at pressure for 30 min. During the bottom phase of the dive, subjects performed mild exercise at approximately 30% of their maximal oxygen uptake. The ascent rate was 9 m/min. Each diver performed graded upright cycle ergometry up to 80% of the maximal oxygen uptake 40 min after the dive. Monitoring of venous gas emboli was performed in both the right and left heart with an ultrasonic scanner every 20 min for 60 min after reaching the surface pressure during supine rest and following two coughs. The diving profile used in this study produced significant amounts of venous bubbles. No evidence of intrapulmonary shunting was found in any subject during either supine resting posture or any exercise grade. Also, short strenuous exercise after the dive did not result in delayed-onset decompression sickness in any subject, but studies with a greater number of participants are needed to confirm whether divers should be allowed to exercise after diving.
Assuntos
Doença da Descompressão/fisiopatologia , Mergulho/efeitos adversos , Embolia Aérea/fisiopatologia , Pulmão/irrigação sanguínea , Pulmão/fisiopatologia , Esforço Físico , Troca Gasosa Pulmonar , Veias/fisiopatologia , Adaptação Fisiológica , Adulto , Doença da Descompressão/etiologia , Embolia Aérea/etiologia , Exercício Físico , Humanos , Masculino , MilitaresRESUMO
PURPOSE: Decompression sickness is initiated by the formation of gas bubbles in tissue and blood if the divers return to surface pressure too fast. The effect of exercise before, during, and after dive on bubble formation is still controversial. We have reported recently that strenuous aerobic exercise 24 h before simulated dive ameliorates venous bubble formation. The objective of this field study was to evaluate whether mild, continuous exercise during decompression has a similar impact. METHODS: Ten healthy, military male divers performed an open-sea field dive to 30 m of sea water breathing air, remaining at pressure for 30 min. During the bottom and decompression the subjects performed fin underwater swimming at about 30% of maximal oxygen uptake. Each diver underwent two randomly assigned dives, one with and one without exercise during the 3-min decompression period. Monitoring of venous gas emboli was performed in the right heart with ultrasonic scanner every 20 min for 60 min after reaching surface pressure in supine rest and during forced two-cough procedure. RESULTS: The study demonstrates that a mild, continuous exercise during decompression significantly reduced the average number of bubbles in the pulmonary artery from 0.9 +/- 0.8 to 0.3 +/- 0.5 bubbles per square centimeter in supine rest, as well as during two-cough procedure, which decreased from 4.6 +/- 4.5 to 0.9 +/- 0.9 bubbles per square centimeter. No symptoms of decompression sickness were observed in any subject. CONCLUSION: These results, obtained in the field conditions, indicate that a mild, underwater swimming during a 3-min decompression period reduces postdive gas bubbles formation.
Assuntos
Doença da Descompressão/prevenção & controle , Mergulho , Exercício Físico , Gases/sangue , Croácia , Humanos , VeiasRESUMO
The aim of this study was to examine the prevalence of dysmenorrhea in female adolescents and the influence of anthropological characteristics and lifestyle factors on menstrual pain. Two hundred and ninety seven girls from several elementary and secondary schools were interviewed about the presence of the menstrual pain, their age, height and weight, menarcheal age, menstrual cycles quality, smoking and sexual activity. There were 164 (55%) subjects with and one hundred and thirty three (45%) without dysmenorrhea. The adolescents with dysmenorrhea answered the questions about missing activities and taking pills for pain. No difference was observed between the girls with and the girls without dysmenorrhea in their chronological age, height, weight, menarcheal age, menstrual cycles quality, cigarette smoking and sexual activity. In the group of dysmenorrheic adolescents there was infrequent missing activities and bedrest, but missing school was observed in 22 percent and taking pills for pain was observed in 96 percent of the subjects. Young girls who experienced menstrual pain are good candidates for a prophylactic therapy, such as hormonal contraception. A replication of this study is needed for public health services in the future to improve the quality of life of the dysmenorrheic young women.