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1.
Zhen Ci Yan Jiu ; 45(1): 40-5, 2020 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-32144907

RESUMO

OBJECTIVE: To investigate the effect of electroacupuncture (EA) at "Jiaji" (EX-B2) at different time points on the expression of OX-42 (a monoclonal antibody with specific expression of complement receptor-3 in spinal microglial cells) and purinergic receptor P2X4 (P2X4) in rats with chronic constriction injury (CCI) of the sciatic nerve, as well as the possible after-effect mechanism of EA analgesia in neuropathic pain. METHODS: Sprague-Dawley rats were randomly divided into blank group, model group, immediately after EA group, 0.5-hour after EA group, 1-hour after EA group, 2-hour after EA group, 4-hour after EA group, 12-hour after EA group, and 24-hour after EA group, with 6 rats in each group. The rats in the model group and the EA groups were used to establish a model of CCI-induced neuropathic pain, and those in the immediately after EA group and the 0.5, 1, 2, 4, 12 and 24 hours after EA groups were treated with EA at bilateral L3 and L5 "Jiaji" points for 20 min after 7 d of modeling. Samples were collected immediately and at 0.5, 1, 2, 4, 12, and 24 hours after EA, and for the rats in the blank group and the model group, samples were collected after fixation the rats for 20 min. Heat pain threshold was observed before and after intervention, and immunohistochemistry was used to measure the protein expression of OX-42 and P2X4 in the spinal cord lumbar enlargement. RESULTS: After 7 days of modeling (before intervention), compared with the blank group, the heat pain threshold had a significant reduction in the model group and the EA groups (P<0.01). Compared with the model group after intervention, the immediately after EA group and the 0.5, 1 and 2 hours after EA groups had a significant increase in heat pain threshold (P<0.05). Compared with the model group, immediately after EA, the 0.5, 1 and 2 hours after EA groups had a significant reduction in the protein expression of OX-42 (P<0.01), and immediately after EA, the 0.5 and 1 hour after EA groups had a significant reduction in the protein expression of P2X4 (P<0.01). CONCLUSION: EA at "Jiaji" points can significantly increase heat pain threshold and down-regulate the protein expression of OX-42 and P2X4 in the spinal cord of CCI rats. The analgesic effect can last for 2 h.


Assuntos
Eletroacupuntura , Analgésicos , Animais , Constrição , Regulação para Baixo , Ratos , Ratos Sprague-Dawley , Medula Espinal
4.
BJOG ; 127(3): 405-413, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31762140

RESUMO

OBJECTIVE: To determine variations in cord blood gas (CBG) parameters after 3-minute delayed cord clamping (DCC) in vaginal deliveries (VDs) and caesarean deliveries (CDs) at term without fetal distress. DESIGN: Prospective observational study. SETTING: University hospital. SAMPLE: CBG from 97 VDs and 124 CDs without fetal distress. METHODS: Comparison of paired arterial-venous CBG parameters drawn at birth from the unclamped cord and after 3-minutes DCC for VDs and CDs. MAIN OUTCOME MEASURES: Base excess, bicarbonate, haematocrit and haemoglobin from both arterial and venous cord blood, lactate, neonatal outcomes, partial pressure of oxygen (pO2 ), partial pressure of carbon dioxide (pCO2 ), pH, and postpartum haemorrhage. RESULTS: Arterial cord blood pH, bicarbonate ( HCO 3 - , mmol/l), and base excess (BE, mmol/l) decreased significantly after 3-minute DCC both in VDs (pH = 7.23 versus 7.27; P < 0.001; HCO 3 -  = 23.3 versus 24.3; P = 0.004; BE = -5.1 versus -2.9; P < 0.001) and CDs (pH = 7.28 versus 7.34; P < 0.001; HCO 3 -  = 26.2 versus 27.2; P < 0.001; BE = -1.5 versus 0.7; P < 0.001). After 3-minute DCC, pCO2 increased in CDs only (57 versus 51; P < 0.001), whereas lactate increased more in CDs compared with VDs (lactate, +1.1 [0.9, 1.45] versus +0.5 [-0.65, 2.35]; P = 0.01). Postpartum maternal haemorrhage, neonatal maximum bilirubin concentration, and need for phototherapy were similar between the two groups. Newborns born by CD more frequently required postnatal clinical monitoring or admission to a neonatal intensive care unit. CONCLUSIONS: After 3-minute DCC, the acid-base status shifted towards mixed acidosis in CDs and prevalent metabolic acidosis in VDs. CDs were associated with a more pronounced increase in arterial lactate, compared with VDs. TWEETABLE ABSTRACT: By 3-minute DCC, acid-base status shifts towards mixed and metabolic acidosis in caesarean and vaginal delivery, respectively.


Assuntos
Acidose , Cesárea , Parto Obstétrico , Sangue Fetal/metabolismo , Complicações do Trabalho de Parto , Cordão Umbilical/cirurgia , Acidose/sangue , Acidose/diagnóstico , Acidose/etiologia , Gasometria/métodos , Cesárea/efeitos adversos , Cesárea/métodos , Cesárea/estatística & dados numéricos , Constrição , Parto Obstétrico/efeitos adversos , Parto Obstétrico/métodos , Parto Obstétrico/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Itália/epidemiologia , Masculino , Complicações do Trabalho de Parto/diagnóstico , Complicações do Trabalho de Parto/epidemiologia , Complicações do Trabalho de Parto/etiologia , Gravidez , Resultado da Gravidez/epidemiologia , Tempo para o Tratamento
5.
Arch Dis Child Fetal Neonatal Ed ; 105(1): 18-25, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31123056

RESUMO

OBJECTIVE: Lung hypoplasia associated with congenital diaphragmatic hernia (CDH) results in respiratory insufficiency and pulmonary hypertension after birth. We have investigated whether aerating the lung before removing placental support (physiologically based cord clamping (PBCC)), improves the cardiopulmonary transition in lambs with a CDH. METHODS: At ≈138 days of gestational age, 17 lambs with surgically induced left-sided diaphragmatic hernia (≈d80) were delivered via caesarean section. The umbilical cord was clamped either immediately prior to ventilation onset (immediate cord clamping (ICC); n=6) or after achieving a target tidal volume of 4 mL/kg, with a maximum delay of 10 min (PBCC; n=11). Lambs were ventilated for 120 min and physiological changes recorded. RESULTS: Pulmonary blood flow (PBF) increased following ventilation onset in both groups, but was 19-fold greater in PBCC compared with ICC lambs at cord clamping (19±6.3 vs 1.0±0.5 mL/min/kg, p<0.001). Cerebral tissue oxygenation was higher in PBCC than ICC lambs during the first 10 min after cord clamping (59%±4% vs 30%±5%, p<0.001). PBF was threefold higher (23±4 vs 8±2 mL/min/kg, p=0.01) and pulmonary vascular resistance (PVR) was threefold lower (0.6±0.1 vs 2.2±0.6 mm Hg/(mL/min), p<0.001) in PBCC lambs compared with ICC lambs at 120 min after ventilation onset. CONCLUSIONS: Compared with ICC, PBCC prevented the severe asphyxia immediately after birth and resulted in a higher PBF due to a lower PVR, which persisted for at least 120 min after birth in CDH lambs.


Assuntos
Débito Cardíaco , Constrição , Hérnias Diafragmáticas Congênitas , Respiração com Pressão Positiva , Circulação Pulmonar , Cordão Umbilical , Animais , Animais Recém-Nascidos , Asfixia Neonatal/prevenção & controle , Encéfalo/metabolismo , Modelos Animais de Doenças , Oxigênio/metabolismo , Ovinos , Volume de Ventilação Pulmonar , Resistência Vascular
6.
World Neurosurg ; 133: e149-e155, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31476473

RESUMO

BACKGROUND: Although new imaging tools have been developed for the detection of smaller aneurysms, angiographically negative microaneurysms are still encountered during cerebral microsurgery. Currently, only limited information regarding incidence and efficacy of treatment of these microaneurysms is available. METHODS: We investigated the incidence and treatment of incidental microaneurysms (IMAs) in the last 5 years. IMAs are unidentifiable and invisible on preoperative angiography, but are detected during microvascular surgery. The inclusion criteria were aneurysm cases treated with microsurgery via transsylvian approaches, and those undergoing preoperative digital subtraction angiography. RESULTS: This study enrolled 484 surgical cases (248 cases of subarachnoid hemorrhage and 236 cases of unruptured aneurysms) in 460 patients, and 33 tiny aneurysms were found in 31 operative cases (6.4% incidence per operation). The most typical type was located on another branching site of the middle cerebral artery found during neck clipping of the middle cerebral artery bifurcation aneurysm. A patient with multiple aneurysms presented a statistically significant risk (375/78 vs. 15/16; P < 0.001) of IMA identification. IMAs were treated by clipping and wrapping in 18 and 15 cases, respectively, without complications. CONCLUSIONS: This study revealed a 6.4% incidence of IMAs; however, this could be underestimated because of the limited range of inspection. Early detection of an IMA through careful inspection during microvascular surgery could be beneficial, especially in patients with multiple aneurysms.


Assuntos
Aneurisma Intracraniano/epidemiologia , Microaneurisma/epidemiologia , Microcirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Aneurisma Roto/cirurgia , Bandagens , Angiografia Cerebral , Comorbidade , Constrição , Craniotomia , Feminino , Humanos , Incidência , Achados Incidentais , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Aneurisma Intracraniano/terapia , Masculino , Microaneurisma/diagnóstico por imagem , Microaneurisma/cirurgia , Microaneurisma/terapia , Pessoa de Meia-Idade
7.
Arch Dis Child Fetal Neonatal Ed ; 105(1): 14-17, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31072967

RESUMO

OBJECTIVE: To assess whether oxytocin administered before clamping the umbilical cord modifies the volume of placental transfusion. DESIGN: Randomised controlled trial. METHODS: Mothers of term infants born vigorous by vaginal delivery with informed consent provided in early labour were randomly assigned to oxytocin (10 IU) given intravenously within 15 s of birth (group 1) or after clamping the umbilical cord 3 min after delivery (group 2). Soon after birth, all infants were weighed using a 1 g precision scale and subsequently placed on the mother's abdomen or chest. At 3 min, in both groups, the cord was clamped and cut, and the weight was again obtained. The primary outcome (volume of placental transfusion) was estimated by the difference in weights. RESULTS: 144 patients were included. There were no differences in the primary outcome: infants in group 1 (n=70) gained a mean weight of 85.9 g (SD 48.3), and in group 2 (n=74) 86.7 g (SD 49.6) (p=0.92). No differences were found in secondary outcomes, including newborns' haematocrit and bilirubin concentrations and severe maternal postpartum haemorrhage. On the advice of the Data and Safety Monitoring Committee, the trial was stopped due to futility at 25% of the planned sample size. CONCLUSIONS: When umbilical cord clamping is delayed for 3 min, term newborn infants born vigorous receive a clinically significant placental transfusion which is not modified by the administration of intravenous oxytocin immediately after birth. TRIAL REGISTRATION NUMBER: NCT02618499.


Assuntos
Constrição , Ocitócicos/administração & dosagem , Ocitocina/administração & dosagem , Circulação Placentária , Período Pós-Parto , Cordão Umbilical , Adulto , Bilirrubina/sangue , Peso ao Nascer , Parto Obstétrico , Feminino , Hematócrito , Maternidades , Humanos , Recém-Nascido , Injeções Intravenosas , Masculino , Hemorragia Pós-Parto/prevenção & controle , Gravidez , Fatores de Tempo , Ganho de Peso
8.
Arch Dis Child Fetal Neonatal Ed ; 105(1): 26-32, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31092674

RESUMO

INTRODUCTION: During delayed umbilical cord clamping, the factors underpinning placental transfusion remain unknown. We hypothesised that reductions in thoracic pressure during inspiration would enhance placental transfusion in spontaneously breathing preterm lambs. OBJECTIVE: Investigate the effect of spontaneous breathing on umbilical venous flow and body weight in preterm lambs. METHODS: Pregnant sheep were instrumented at 132-133 days gestational age to measure fetal common umbilical venous, pulmonary and cerebral blood flows as well as arterial and intrapleural (IP) pressures. At delivery, doxapram and caffeine were administered to promote breathing. Lamb body weights were measured continuously and breathing was assessed by IP pressure changes. RESULTS: In 6 lambs, 491 out of 1117 breaths were analysed for change in body weight. Weight increased in 46.6% and decreased in 47.5% of breaths. An overall mean increase of 0.02±2.5 g per breath was calculated, and no net placental transfusion was observed prior to cord clamping (median difference in body weight 52.3 [-54.9-166.1] g, p=0.418). Umbilical venous (UV) flow transiently decreased with each inspiration, and in some cases ceased, before UV flow normalised during expiration. The reduction in UV flow was positively correlated with the standardised reduction in (IP) pressure, increasing by 109 mL/min for every SD reduction in IP pressure. Thus, the reduction in UV flow was closely related to inspiratory depth. CONCLUSIONS: Spontaneous breathing had no net effect on body weight in preterm lambs at birth. UV blood flow decreased as inspiratory effort increased, possibly due to constriction of the inferior vena cava caused by diaphragmatic contraction, as previously observed in human fetuses.


Assuntos
Circulação Placentária/fisiologia , Respiração , Cordão Umbilical , Veias Umbilicais/fisiologia , Animais , Animais Recém-Nascidos , Velocidade do Fluxo Sanguíneo/fisiologia , Peso Corporal , Constrição , Modelos Animais de Doenças , Feminino , Gravidez , Nascimento Prematuro , Ovinos , Fatores de Tempo
10.
J Ethnopharmacol ; 246: 112154, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31415848

RESUMO

Treating ventricular remodeling continues to be a clinical challenge. Studies have shown that hypertension is one of the most common causes of ventricular remodeling, and is a major cause of cardiovascular risk in adults. Here, we report that Tongsaimai (TSM), a Chinese traditional medicine, could inhibit arterial pressure and left ventricular pressure to improve hemodynamic abnormalities in rats impaired by abdominal aortic constriction (AAC). Administration of TSM significantly reduced the heart mass index and the left ventricular mass index significantly in AAC rats. TSM could also markedly ameliorate cardiac collagen deposition and reduce the concentration of hydroxyproline in the heart of AAC rats. Moreover, TSM alleviated cardiac histomorphology injury resulting from AAC, including reducing cardiomyocyte hypertrophy, fibrous connective tissue hyperplasia, cardiomyocyte apoptosis, replacement fibrosis and the disorders of myocardial myofibrils, intercalated discs, mitochondria and mitochondrial crista. In addition, the levels of transforming growth factor (TGF) - ß and inflammation-related molecules including tumor necrosis factor-α (TNF-α), which were over-expressed with AAC, were decreased by STM. In conclusion, STM could reverse the hypertension and left ventricular remolding caused by abdominal aortic constriction in rats.


Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Remodelação Ventricular/efeitos dos fármacos , Animais , Anti-Hipertensivos/farmacologia , Aorta Abdominal , Pressão Arterial/efeitos dos fármacos , Cardiomegalia/tratamento farmacológico , Cardiomegalia/metabolismo , Cardiomegalia/patologia , Colágeno/metabolismo , Constrição , Hipertensão/metabolismo , Hipertensão/patologia , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Ratos Sprague-Dawley , Sistema Renina-Angiotensina/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-31869012

RESUMO

Coronary artery bypass grafting offers patients a better long-term prognosis than catheter intervention, but it carries a higher risk of perioperative stroke. To reduce cerebral complications associated with proximal anastomosis, preprocedural epiaortic ultrasound assessment, avoidance of aortic clamping, and the use of an anastomosis assist device are useful. For multivessel bypass across two regions, piggyback anastomosis, which stacks the proximal anastomoses of the two grafts, reduces aortic invasion because this technique requires only one proximal anastomosis. In addition, this method uses only one device, which helps to reduce costs.  The Heartstring is considered among the least invasive of the various anastomosis assist devices. However, its removal is irreversible, and once the sutures are cut, repair without aortic clamping is difficult.  We have developed a safe method for performing a piggyback anastomosis using a single Heartstring device. This cost-effective technique produces a safe piggyback anastomosis with minimal invasiveness to the aorta.


Assuntos
Ponte de Artéria Coronária/instrumentação , Idoso , Anastomose Cirúrgica/métodos , Aorta/cirurgia , Constrição , Feminino , Humanos , Masculino , Veia Safena/transplante , Acidente Vascular Cerebral/etiologia , Instrumentos Cirúrgicos , Técnicas de Sutura
16.
JAMA ; 322(19): 1869-1876, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31742629

RESUMO

Importance: The American College of Obstetricians and Gynecologists recommends a delay in umbilical cord clamping in term neonates for at least 30 to 60 seconds after birth. Most literature supporting this practice is from low-risk vaginal deliveries. There are no published data specific to cesarean delivery. Objective: To compare maternal blood loss with immediate cord clamping vs delayed cord clamping in scheduled cesarean deliveries at term (≥37 weeks). Design, Setting, and Participants: Randomized clinical trial performed at 2 hospitals within a tertiary academic medical center in New York City from October 2017 to February 2018 (follow-up completed March 15, 2018). A total of 113 women undergoing scheduled cesarean delivery of term singleton gestations were included. Interventions: In the immediate cord clamping group (n = 56), cord clamping was within 15 seconds after birth. In the delayed cord clamping group (n = 57), cord clamping was at 60 seconds after birth. Main Outcomes and Measures: The primary outcome was change in maternal hemoglobin level from preoperative to postoperative day 1, which was used as a proxy for maternal blood loss. Secondary outcomes included neonatal hemoglobin level at 24 to 72 hours of life. Results: All of the 113 women who were randomized (mean [SD] age, 32.6 [5.2] years) completed the trial. The mean preoperative hemoglobin level was 12.0 g/dL in the delayed and 11.6 g/dL in the immediate cord clamping group. The mean postoperative day 1 hemoglobin level was 10.1 g/dL in the delayed group and 9.8 g/dL in the immediate group. There was no significant difference in the primary outcome, with a mean hemoglobin change of -1.90 g/dL (95% CI, -2.14 to -1.66) and -1.78 g/dL (95% CI, -2.03 to -1.54) in the delayed and immediate cord clamping groups, respectively (mean difference, 0.12 g/dL [95% CI, -0.22 to 0.46]; P = .49). Of 19 prespecified secondary outcomes analyzed, 15 showed no significant difference. The mean neonatal hemoglobin level, available for 90 neonates (79.6%), was significantly higher with delayed (18.1 g/dL [95% CI, 17.4 to 18.8]) compared with immediate (16.4 g/dL [95% CI, 15.9 to 17.0]) cord clamping (mean difference, 1.67 g/dL [95% CI, 0.75 to 2.59]; P < .001). There was 1 unplanned hysterectomy in each group. Conclusions and Relevance: Among women undergoing scheduled cesarean delivery of term singleton pregnancies, delayed umbilical cord clamping, compared with immediate cord clamping, resulted in no significant difference in the change in maternal hemoglobin level at postoperative day 1. Trial Registration: ClinicalTrials.gov Identifier: NCT03150641.


Assuntos
Cesárea , Constrição , Hemoglobinas/análise , Hemorragia Pós-Operatória/prevenção & controle , Cordão Umbilical , Adulto , Gasometria , Procedimentos Cirúrgicos Eletivos , Feminino , Sangue Fetal/química , Humanos , Concentração de Íons de Hidrogênio , Recém-Nascido/sangue , Masculino , Hemorragia Pós-Operatória/epidemiologia , Gravidez , Nascimento a Termo , Fatores de Tempo
17.
JAMA ; 322(19): 1877-1886, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31742630

RESUMO

Importance: Umbilical cord milking as an alternative to delayed umbilical cord clamping may provide equivalent benefits to preterm infants, but without delaying resuscitation. Objective: To determine whether the rates of death or severe intraventricular hemorrhage differ among preterm infants receiving placental transfusion with umbilical cord milking vs delayed umbilical cord clamping. Design, Setting, and Participants: Noninferiority randomized clinical trial of preterm infants (born at 23-31 weeks' gestation) from 9 university and private medical centers in 4 countries were recruited and enrolled between June 2017 and September 2018. Planned enrollment was 750 per group. However, a safety signal comprising an imbalance in the number of severe intraventricular hemorrhage events by study group was observed at the first interim analysis; enrollment was stopped based on recommendations from the data and safety monitoring board. The planned noninferiority analysis could not be conducted and a post hoc comparison was performed instead. Final date of follow-up was December 2018. Interventions: Participants were randomized to umbilical cord milking (n = 236) or delayed umbilical cord clamping (n = 238). Main Outcomes and Measures: The primary outcome was a composite of death or severe intraventricular hemorrhage to determine noninferiority of umbilical cord milking with a 1% noninferiority margin. Results: Among 540 infants randomized, 474 (88%) were enrolled and completed the trial (mean gestational age of 28 weeks; 46% female). Twelve percent (29/236) of the umbilical cord milking group died or developed severe intraventricular hemorrhage compared with 8% (20/238) of the delayed umbilical cord clamping group (risk difference, 4% [95% CI, -2% to 9%]; P = .16). Although there was no statistically significant difference in death, severe intraventricular hemorrhage was statistically significantly higher in the umbilical cord milking group than in the delayed umbilical cord clamping group (8% [20/236] vs 3% [8/238], respectively; risk difference, 5% [95% CI, 1% to 9%]; P = .02). The test for interaction between gestational age strata and treatment group was significant for severe intraventricular hemorrhage only (P = .003); among infants born at 23 to 27 weeks' gestation, severe intraventricular hemorrhage was statistically significantly higher with umbilical cord milking than with delayed umbilical cord clamping (22% [20/93] vs 6% [5/89], respectively; risk difference, 16% [95% CI, 6% to 26%]; P = .002). Conclusions and Relevance: In this post hoc analysis of a prematurely terminated randomized clinical trial of umbilical cord milking vs delayed umbilical cord clamping among preterm infants born at less than 32 weeks' gestation, there was no statistically significant difference in the rate of a composite outcome of death or severe intraventricular hemorrhage, but there was a statistically significantly higher rate of severe intraventricular hemorrhage in the umbilical cord milking group. The early study termination and resulting post hoc nature of the analyses preclude definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT03019367.


Assuntos
Hemorragia Cerebral Intraventricular/prevenção & controle , Constrição , Doenças do Prematuro/prevenção & controle , Recém-Nascido Prematuro , Cordão Umbilical , Término Precoce de Ensaios Clínicos , Feminino , Idade Gestacional , Humanos , Lactente , Morte do Lactente , Recém-Nascido , Doenças do Prematuro/mortalidade , Masculino , Gravidez
18.
Int J Oral Maxillofac Implants ; 34(5): 1084-1090, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31528862

RESUMO

PURPOSE: Stability of an implant-supported restoration is an ultimate measure of the success of the procedure. It has been recommended by some to retighten the abutment screw for maintenance of the crown on the implant. The purpose of this study was to evaluate the usefulness of two retightening protocols to maintain the clamping force. MATERIALS AND METHODS: Three groups of slip-fit implants (MIS 4.3 by 10.5) were compared. The first group was only tightened once (group C). In the second group (group R10M), the screw was retightened after 10 minutes. The third group (group R2W) was retightened after 2 weeks of simulated functional loading. After completion of individual protocols, all specimens were loaded for 100,000 cycles. After the loading, all specimens had the remaining torque audited. RESULTS: The mean torque loss for group C was 6.10 (± 5.13) Ncm. Group R10M was 2.03 (± 3.018) Ncm, and group R2W was 0.30 (± 0.483) Ncm. A one-way analysis of variance (ANOVA) recorded significant differences among the groups (P = .003). Multiple pairwise comparisons between groups by Tukey test recorded significant differences between group C vs group R10M (P = .035) and group C vs group R2W (P = .002). There was no significant difference in torque loss between groups R10M and R2W (P = .509). CONCLUSION: Within the parameters of this in vitro investigation, it was concluded that both retightening after 10 minutes (P = .035) and after 2 weeks (P = .002) was equally effective.


Assuntos
Dente Suporte , Projeto do Implante Dentário-Pivô , Constrição , Análise do Estresse Dentário , Teste de Materiais , Projetos Piloto , Torque
19.
J Surg Res ; 244: 587-598, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31521941

RESUMO

BACKGROUND: Immediate changes in vascular mechanics during aortic cross-clamping remain widely unknown. By using a numerical model of the arterial network, vascular compliance and resistance can be estimated and the time constant of pressure waves can be calculated and compared with results from the classic arterial waveform analysis. METHODS: Experimental data were registered from continuous invasive radial artery pressure measurements from 11 patients undergoing vascular surgery. A stable set of beats were chosen immediately before and after each clamping event. Through the arterial waveform analysis, the time constant was calculated for each individual beat and for a mean beat of each condition as to compare with numerical simulations. Overall proportional changes in resistance and compliance during clamping and unclamping were calculated using the numerical model. RESULTS: Arterial waveform analysis of individual beats indicated a significant 10% median reduction in the time constant after clamping, and a significant 17% median increase in the time constant after unclamping. There was a positive correlation between waveform analysis and numerical values of the time constant, which was moderate (ρ = 0.51; P = 0.01486) during clamping and strong (ρ = 0.77; P ≤ 0.0001) during unclamping. After clamping, there was a significant 16% increase in the mean resistance and a significant 23% decrease in the mean compliance. After unclamping, there was a significant 19% decrease in the mean resistance and a significant 56% increase in the mean compliance. CONCLUSIONS: There are significant hemodynamic changes in vascular compliance and resistance during aortic clamping and unclamping. Numerical computer models can add information on the mechanisms of injury due to aortic clamping.


Assuntos
Pressão Arterial , Modelos Teóricos , Monitorização Intraoperatória/métodos , Artéria Radial/fisiologia , Resistência Vascular , Procedimentos Cirúrgicos Vasculares , Idoso , Idoso de 80 Anos ou mais , Constrição , Estudos Transversais , Feminino , Humanos , Complicações Intraoperatórias/prevenção & controle , Masculino , Pessoa de Meia-Idade , Artéria Radial/lesões , Lesões do Sistema Vascular/etiologia , Lesões do Sistema Vascular/prevenção & controle
20.
J Sports Sci ; 37(24): 2798-2805, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31500494

RESUMO

Ischaemic preconditioning (IPC) has emerged as a potential non-invasive ergogenic aid to enhance exercise performance. Repeated application of IPC has demonstrated clinical efficacy, therefore our aims were to investigate its effect on endurance cycling performance and muscle efficiency. Twenty participants undertook 7-d repeated bilateral lower limb occlusion (4 x 5-min) of IPC (220 mmHg) or sham (20 mmHg). Prior to and 72-h following the intervention, participants performed submaximal cycling at 70, 80 and 90% of ventilatory threshold (VT) followed by an incremental exercise test. IPC had no effect on V˙ O2max (P = 0.110); however, time to exhaustion increased by ~ 9% and Wmax by ~ 5 % (IPC pre 307 ± 45 to post 323 ± 51 W) relative to sham (P = 0.002). There were no changes in gross efficiency (GE) (P > 0.05); however, delta efficiency (DE) increased by 3.1% following IPC (P = 0.011). Deoxyhaemoglobin (HHb) was reduced following IPC ~ 30% (P = 0.017) with no change in total haemoglobin (tHb). Repeated IPC over 7-d enhanced muscle efficiency and extended cycling performance. The physiological effects of repeated IPC on skeletal muscle efficiency explains the notable improvements in endurance performance.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Precondicionamento Isquêmico , Músculo Esquelético/fisiologia , Constrição , Estudos Cross-Over , Teste de Esforço , Hemoglobinas/análise , Humanos , Extremidade Inferior , Masculino , Consumo de Oxigênio , Método Simples-Cego , Espectroscopia de Luz Próxima ao Infravermelho , Adulto Jovem
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