Effect of estrogen administration on middle cerebral arterial viscoelastic properties in aged female rats

ABSTRACT PURPOSE: To develop a model for studying cerebrovascular disease prevention in elderly women. METHODS: Sixty 18-month-old Sprague Dawley (SD) rats were randomly divided into an estrogen administration group (EA, n=30) and a non-administration group (NA, n=30); thirty 4-month-old SD rats were allocated to a control group. The EA group received estradiol benzoate starting on the 5th day of a 34-day breeding period, and the serum levels of estradiol (E2), estrogen receptor (ER), and malondialdehyde (MDA) were measured. The MCA of each group was then sampled for viscoelastic experiments. RESULTS: The serum levels of E2 and MDA in the EA group showed significant differences compared to those in the control group (p<0.05), while the difference in ER between the EA and control groups was not significant (p>0.05). The decrease in MCA stress at 7,200 s and the increase in strain at 7,200 s in the EA group showed no significant differences compared to the control group (p>0.05). CONCLUSION: Estradiol administration inhibited the formation of lipid peroxidation products and restored middle cerebral arterial viscoelasticity in aged female rats.

Intervalos de referência longitudinais de parâmetros doplervelocimétricos materno-fetais / Longitudinal reference intervals of maternal-fetal Doppler parameters

OBJETIVO: Criar intervalos de referência longitudinais para os valores de índices de pulsatilidade (IP) dos fluxos nas artérias umbilicais (AU), cerebral média (ACM) e uterinas (AUt) e IP venoso do fluxo no ducto venoso (DV) com uma amostra da população brasileira. MÉTODOS: Estudo observacional longitudinal realizado de fevereiro de 2010 a maio de 2012. Gestantes de baixo risco foram submetidas a exames ultrassonográficos quinzenais da 18ª a 40ª semana para obtenção dos IP das AU, AUt, ACM e IP venoso do DV. Modelos lineares mistos foram usados para elaboração de intervalos de referência longitudinais (percentis 5, 50 e 95) dos IP dos vasos mencionados. Os IP das porções placentária e abdominal do cordão umbilical foram comparados por meio do teste t de amostras independentes. Valores de p bilaterais menores do que 0,05 foram considerados significativos. RESULTADOS: Cento e sessenta e quatro gestantes foram submetidas a 1.242 exames ultrassonográficos. Houve redução significativa nos valores de todos esses parâmetros com o avançar da IG. Entre a 18ª e a 40ª semana de gravidez, as medianas de IP da AU (porções abdominal e placentária do cordão), da ACM, do DV e do IP médio das AUt variaram de 1,19 a 0,74; 1,33 a 0,78; 1,56 a 1,39; 0,58 a 0,41; e 0,98 a 0,66, respectivamente. As equações obtidas para predição das medianas foram: IP-AU=1,5602786 - (0,020623 x IG); Logaritmo do IP-ACM=0,8149111 - (0,004168 x IG) - [0,002543 x (IG - 28,7756)²]; Logaritmo do IP-DV=-0,26691- (0,015414 x IG); IP-AUt=1,2362403 - (0,014392 x IG). Houve diferença significativa entre os IP-AU obtidos nas extremidades placentária e abdominal fetal (p<0,001). CONCLUSÃO: Foram estabelecidos intervalos de referência longitudinais dos parâmetros doplervelocimétricos gestacionais mais importantes em uma amostra da população brasileira. Estes podem ser mais adequados para o acompanhamento das modificações hemodinâmicas materno-fetais em gestações normais ou não, o que ainda requer validação futura.

PURPOSE: To create longitudinal reference intervals for pulsatility index (PI) of the umbilical (UA), middle cerebral (MCA), uterine (UtA) arteries and ductus venosus (DV) in a Brazilian cohort. METHODS: A longitudinal observational study performed from February 2010 to May 2012. Low risk pregnancies were scanned fortnightly from 18 to 40 weeks for the measurements of PI of the UA, MCA, DV and UtA. Linear mixed models were used for the elaboration of longitudinal reference intervals (5th, 50th and 95th percentiles) of these measurements. PI obtained for the placental and abdominal portions of the umbilical artery were compared by the t-test for independent samples. Two-sided p values of less than 0.05 were considered statistically significant. RESULTS: A total of 164 patients underwent 1,242 scans. There was significant decrease in PI values of all vessels studied with gestational age (GA). From the 18th to the 40th week of pregnancy, the median PI values of UA (abdominal and placental ends of the cord), MCA, DV and the mean PI of the UtA ranged from 1.19 to 0.74, 1.33 to 0.78, 1.56 to 1.39, 0.58 to 0.41, and 0.98 to 0.66, respectively. The following equations were obtained for the prediction of the medians: PI-UA=1.5602786 - (0.020623 x GA); Logarithm of the PI-MCA=0.8149111 - (0.004168 x GA) - [0.02543 x (GA - 28.7756)²]; Logarithm of the PI-DV=-0.26691- (0.015414 x GA); PI-UtA = 1.2362403 - (0.014392 x GA). There was a significant difference between the PI-UA obtained at the abdominal and placental ends of the umbilical cord (p<0.001). CONCLUSIONS: Longitudinal reference intervals for the main gestational Doppler parameters were obtained in a Brazilian cohort. These intervals could be more adequate for the follow-up of maternal-fetal hemodynamic modifications in normal and abnormal pregnancies, a fact that still requires further validation.

Repercussões agudas do exercício físico materno sobre os parâmetros hemodinâmicos útero-placentários e fetais / Impact of acute maternal exercise on uteroplacental and fetal hemodynamics patterns

A atividade física está associada a diversos benefícios para a saúde física e mental. Entre as gestantes, a prática de exercícios físicos ganhou maior ênfase nas últimas décadas, porém, ainda persistem controvérsias quanto à possibilidade da ocorrência de potenciais efeitos lesivos ao feto. Esta revisão avaliou os estudos existentes que investigaram os efeitos agudos dos exercícios físicos maternos sobre os parâmetros hemodinâmicos útero-placentários e fetais. Verifica-se que ocorrem graus de desvio do fluxo sanguíneo para a musculatura esquelética solicitada durante o exercício. Esse efeito é acompanhado de vasoconstrição visceral e provável redução do fluxo uterino. Entretanto, em gestações normais, mecanismos compensatórios atuam no leito vascular útero-placentário e no feto, garantindo a homeostase das trocas gasosas e impedindo efeitos deletérios da hipoxia fetal. A análise dos estudos desta revisão permite conlcuir que os exercícios considerados de moderada intensidade em gestações não complicadas parecem ser seguros e podem ser recomendados.

Physical activity is associated with several benefits to physical and mental health. Among pregnant women, the practice of physical exercises has gained more emphasis over the last few decades, but controversy still persists regarding the possible occurrence of potential damaging effects on the fetus. The present systematic review evaluated existing studies that investigated the acute effects of maternal physical exercise on the hemodynamic uteroplacental and fetal parameters. The occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This effect is accompanied by visceral vasoconstriction and by a probable reduction of uterine flow. However, in normal pregnancies, compensatory mechanisms may act on the uteroplacental vascular bed and on the fetus, in order to guarantee the homeostasis of gas exchanges and prevent deleterious effects of fetal hypoxia. Analysis of the studies reviewed in this survery permits us to conclude that exercises of moderate intensity in uncomplicated pregnancies seem to be safe and can be recommended.

Relação cerebroplacentária e acidemia ao nascimento em gestações com insuficiência placentária detectada antes da 34ª semana de gestação / Cerebroplacental ratio and acidemia to the birth in placental insufficiency detected before 34th week's gestation

OBJETIVO: avaliar a hipótese de que a relação cerebroplacentária (RCP) fetal relaciona-se com acidemia no nascimento, em gestações complicadas pela insuficiência placentária detectada antes da 34ª semana de gestação. MÉTODOS: trata-se de coorte prospectiva de 55 pacientes entre a 26ª e a 34ª semanas de gestação, com diagnóstico de insuficiência placentária caracterizada pelo Doppler de artéria umbilical alterado (índice de pulsatilidade >p95). Para cada paciente foi realizada avaliação da vitalidade fetal pela doplervelocimetria de artéria umbilical, artéria cerebral média e ducto venoso, e pelo perfil biofísico fetal. Foi calculada a RCP pela razão entre os valores do índice de pulsatilidade da artéria umbilical e da artéria cerebral média, bem como o cálculo de seu z-score (número de desvios padrão que se afasta da média para a idade gestacional). A acidemia no nascimento foi caracterizada quando pH<7,2. RESULTADOS: das 55 pacientes, 29 (52,7 por cento) apresentaram acidemia no nascimento. O grupo com acidemia, comparado ao grupo com pH>7,2, apresentou associação significativa com os valores da RCP (mediana 0,47 versus 0,58; p=0,009), índice de pulsatilidade da artéria umbilical (mediana 2,45 versus 1,93; p=0,003), índice de pulsatilidade para veias (IPV) do ducto venoso (mediana 1,08 versus 0,85; p=0,034) e perfil biofísico fetal suspeito ou alterado (37 versus 8 por cento; p=0,031). A análise da RCP pelo seu z-score demonstrou tendência de maior afastamento negativo da média, mas sem atingir valor significativo (p=0,08). Foi constatada correlação significativa entre o pH no nascimento e a RCP (r=0,45; p<0,01), o z-score da RCP (r=0,27; p<0,05) e o IPV do ducto venoso (r=-0,35 p<0,01). CONCLUSÃO: A RCP associa-se à presença de acidemia no nascimento nas gestações com insuficiência placentária antes da 34ª semana, e esse parâmetro pode configurar potencial fator para avaliação da gravidade do comprometimento fetal.

PURPOSE: to evaluate the hypothesis that the fetal cerebroplacental ratio (CPR) is related to acidemia at birth in pregnancies complicated by placental insufficiency detected before 34 weeks of gestation. METHODS: this is a prospective cohort study of 55 patients between 26 and 34 weeks of gestation with a diagnosis of placental insufficiency characterized by abnormal umbilical artery Doppler (pulsatility index>95p). Fetal assessment was performed for each patient by dopplervelocimetry of the umbilical artery, middle cerebral artery and ductus venosus, and by the fetal biophysical profile. CPR was calculated using the ratio between middle cerebral artery pulsatility index and umbilical artery pulsatility index, and the z-score was obtained (number of standard deviations of the mean value at each gestational age). Acidemia at birth was characterized when pH<7.2. RESULTS: of 55 patients, 29 (52.7 percent) presented acidemia at birth. In the group of fetal acidemia, when compared with the group with pH>7.2, a significant association was observed with CPR values (median 0.47 versus 0.58; p=0.009), pulsatility index of the umbilical artery (median 2.45 versus 1.93; p=0.003), ductus venosus pulsatility index for veins (PIV) (median 1.08 versus 0.85; p=0.034) and suspected or abnormal fetal biophysical profile (37 versus 8 percent; p=0.031). CPR analysis by z-score showed a negative tendency, but was not statistically significant (p=0.080). Significant correlations were found between pH at birth and CPR (r=0.45; p<0.01), z-score of CPR (r=0.27; p<0.05) and ductus venosus PIV (r=-0.35 p<0.01). CONCLUSION: CPR is associated with the presence of acidemia at birth in pregnancies with placental insufficiency detected before 34 weeks of gestation and this parameter could potentially represent a factor for assessing the severity of fetal involvement.

Isoinmunización antikell: manejo clínico de 26 casos / Antikell alloinmunization: clinical management of 26 cases

La principal causa de anemia fetal es la isoinmunización Rh por el desarrollo de anticuerpos frente al antí-geno D. La aloinmunización antiKell es una patología poco frecuente aunque puede producir un cuadro de anemia fetal muy grave. Su incidencia relativa ha aumentado en los últimos años debido al mayor número de transfusiones sanguíneas por disminución de la isoinmunización anti-D. Presentamos 26 casos de isoin-munización antiKell controlados en el Hospital La Paz de Madrid, durante los años 2003-2009 y una revisión de la literatura.

The main cause of fetal anemia is red-cell alloimmunization. Kell alloinmunization is a rare disease, although it can produce severe fetal damages. The relative incidence of antiKell isoinmunization has increased last years due to the blood transfusions has grown also, and anti-D aloinmunization has decreased. We report twenty six cases of pregnant women with isoinmunization antikell controlled in La Paz Hospital, Madrid, between 2003-2009 and a review of the literature.

Doppler en obstetricia / Doppler ultrasound in obstetrics

La aplicación del ultrasonido Doppler en Obstetricia ha determinado un avance importante en el cuidado de la salud fetal. Para el correcto uso de esta metodología es necesario poseer un acabado conocimiento de los principios físicos y de instrumentación. Así mismo es necesaria la adecuada interpretación de los resultados en cada uno de los diferentes territorios vasculares que se exploren. De tal manera la evaluación de las arterías uterinas constituye una herramienta de utilidad en el tamizaje de patologías del embarazo tales como preeclampsia, restricción de crecimiento intrauterino, desprendimiento de placenta y muerte fetal. El estudió de la forma de onda de velocidad de flujo de la artería umbilical se utiliza rutinariamente en el manejo de embarazos de alto riesgo con sospecha de hipoxia y los cambios en la velocimetría de la arteria cerebral medía son de utilidad en la evaluación de fetos con insuficiencia placentaria y anemia fetal. Finalmente mediante el estudio Doppler del sistema venoso fetal se dectectan estados más avanzados de hipoxia fetal generalmente acompañados de acidemia e insuficiencia cardiaca. En este artículo se revisan estas diferentes aplicaciones del Doppler en Obstetricia con el propósito de brindar al lector los principios elementales para su correcta aplicación.

The introduction of Doppler ultrasound in Obstetrics has determined an important advance in the care of fetal health. The adequate use of this methodology requires the knowledge of the physical principles and instrumentation of Doppler ultrasound. It is also of capital importance the correct interpretation of the findings in each one of the different vascular territories explored. Uterine artery Doppler ultrasound examination is considered a potential screening tool for the development of pre-eclampsia, fetal growth restriction, placental abruption and still birth. Umbilical artery Doppler waveform analysis is routinely used in the management of high-risk pregnancies with suspected hypoxia and middle cerebral artery recordings are incorporated regularly into the management of fetuses at risk of developing placental compromise and fetal anemia. Additionally Doppler evaluation of the fetal venous system is useful in the assessment of severe fetal hypoxia usually in association with acidemia and heart failure. In this article the different applications of Doppler ultrasound in Obstetrics are reviewed.

El doppler de la arteria cerebral media reemplaza a la espectrofotometría del líquido amniótico como el estandar en el manejo de la isoinmunización fetal / Doppler of the middle cerebral artery replace to amniotic fluid spectrophotometry as the standard care in the management of fetal alloimmunization

La anemia fetal puede ser una condición devastadora para el feto. La principal causa de anemia fetal es la sensibilización materna por el antígeno D. El estándar actual para la evaluación de los fetos en riesgo de anemia es la espectrofotometría del líquido amniótico. Esta aproximación enfrenta problemas como: la necesidad de extrapolación del análisis a edades gestacionales menores de 27 semanas y la evaluación de fetos en riesgo de anemia por otras causas, esto sumado al riesgo propio de la amniocentesis. En los últimos 10 a 12 años ha surgido un método no invasivo para la evaluación de los fetos en riesgo de anemia: la medición del peak sistólico de la velocidad del flujo de la arteria cerebral media. La velocidad de flujo aumentada sería un reflejo de la anemia fetal, justificando que esta técnica se esté incorporando en forma paulatina en el manejo de éstos pacientes. En esta revisión presentamos la evidencia disponible para sustentar que el uso rutinario de esta técnica no invasiva, reemplaza el manejo convencional con amniocentesis, espectrofotometría del líquido amniótico y manejo según curvas de Liley, en pacientes Rh-negativas sensibilizadas, o en otras situaciones de riesgo de anemia fetal.

Fetal anemia could be a devastating condition to the fetus. The main cause of fetal anemia is red-cell alloimmunization. The standard of care for this condition has been the serial amniocentesis to measure bilirubin levels by spectrophotometry of the amniotic fluid. Amniotic fluid bilirubin measurements are of limited value in the second trimester and in other causes of fetal anemia, besides amniocentesis is an invasive method with fetal risk. During the last 10 to 12 years a non invasive method to predict fetal anemia become available: measurement of the peak systolic velocity of the middle cerebral artery. Increased velocity may reflect fetal anemia. Here we present the evidence to support the use of this non invasive method to replace amniocentesis as the standard care in the management of red-cell alloimmunization and other causes of fetal anemia.

Lacunar Infarction in Type 2 Diabetes Is Associated with an Elevated Intracranial Arterial Pulsatility Index

PURPOSE: The arterial pulsatility index (PI) is measured by transcranial Doppler ultrasonography (TCD) and is postulated to reflect the vascular resistance distal to the artery being examined. An increased PI of the intracranial artery is often reported with diabetes mellitus (DM), old age, hypertension, intracranial hypertension, vascular dementia, and small artery disease. Microvascular complication of DM, which may contribute to cerebral infarction, involves the small perforating artery and may influence the PI of the proximal artery. MATERIALS AND METHODS: We performed a TCD examination in patients with type 2 DM with acute lacunar infarction (DML, n=35), type 2 DM without cerebral infarction (DMO, n=69), and in control cases with no DM or cerebral infarction (control group, n=41). We then compared the TCD findings among these groups. RESULTS: The PI was significantly higher in the DML and DMO groups than in the control group (1.05, 0.93, 0.73. respectively, for the right middle cerebral artery; 1.04, 0.90, 0.73, respectively, for the left middle cerebral artery; 0.97, 0.89, 0.70, respectively, for the basilar artery). The PI was also significantly higher in the DML group than in the DMO group for both middle cerebral arteries. The flow velocity was comparable among the three groups. CONCLUSION: The elevated PI of the intracranial arteries may reflect diabetic cerebral microvascular complications. The PI measurement using TCD may be a useful predictor of lacunar infarction in type 2 DM patients.

Microanatomía de los segmentos M1 y M2 de la arteria cerebral media en hemisferios humanos de origen chileno: correlación con la literatura internacional / Median cerebral artery segments M1 and M2 microanatomy in chilean human hemispheres: correlation with international literature

La arteria cerebral media (ACM) es el más largo y complejo de todos los vasos intracerebrales, irrigando la mayor parte de los lóbulos frontales, parietales y temporales de ambos hemisferios cerebrales. Además de suplir el riego sanguíneo de una gran parte del cerebro, la ACM y sus ramas, están frecuentemente involucradas en enfermedades intracerebrales como hemorragias cerebrales, patología ateroesclerótica o degenerativa de la pared arterial, embolias y procesos inflamatorios. La alta frecuencia de patología y el amplio volumen cerebral irrigado por esta arteria hacen que el conocimiento de su anatomía sea fundamental en la descripción de los posibles mecanismos fisiopatológicos de las enfermedades que la involucran, así como para su estudio imagenológico y abordaje quirúrgico. El objetivo de este trabajo es comparar la anatomía macroscópica y microscópica de la ACM de sujetos chilenos con la publicada en series internacionales. Se estudiaron 10 hemisférios cadavéricos provenientes de 5 pacientes adultos de nacionalidad chilena cuya muerte no fue de causa encefálica, fijados con solución de formalina sometiendo a tinción los vasos arteriales. Se realizaron mediciones de la ACM y sus segmentos M1 y M2 comparando mediante análisis estadístico los resultados obtenidos con los publicados en la literatura. El análisis de éstos sugiere que las características anatómicas de la ACM de hemisferios provenientes de sujetos de nacionalidad chilena son similares a los reportados por estudios realizados con hemisferios cerebrales de sujetos de origen anglo-sajón.

Hemodinâmica fetal avaliada pela dopplervelocimetria na segunda metade da gestação / Fetal hemodynamics evaluated by doppler velocimetry in the second half of pregnancy

Dentre várias aplicabilidades, a dopplervelocimetria obstétrica tem sido utilizada na restrição de crescimento intra-uterino, hipóxia fetal, anemia e nas malformações cardíacas fetais. Para estas aplicações, as principais artérias fetais avaliadas são a artéria cerebral média e a artéria umbilical. A aorta fetal também deve ser valorizada porque é responsável pela distribuição do fluxo sanguíneo para as extremidades superiores e inferiores do corpo humano. Para a caracterização de anormalidades nas artérias fetais em fetos de alto risco, é necessário conhecer as modificações hemodinâmicas de fetos normais. Neste particular, os autores fazem revisão sobre a hemodinâmica fetal avaliada pela dopplervelocimetria nas artérias fetais aorta, cerebral média e umbilical da 22ª a 38ª semana de gestação. Relatam resultados dopplervelocimétricos nas artérias de fetos normais que podem ser comparados com os encontrados em fetos de alto risco

Transcranial Doppler sonography evaluation in patients with vasospasm following subarachnoid haemorrhage.

Transcranial Doppler (TCD) sonography is emerging as a new ultrasonography technology to look at the interaction between the brain parenchyma and perfusion during cerebrovascular accident. Before TCD sonography the vasospasm following subarachnoid haemorrhage could only be diagnosed either clinically or by invasive method ie, angiography. TCD has been proved as a wonderful non-invasive, repeatable, beat-by-beat, non-expensive technique for detection and follow-up of vasospasm after subarachnoid haemorrhage. In the present series 12 patients suspected to have vasospasm after subarachnoid haemorrhage were confirmed and monitored with the help of TCD. Most of the patients were clinically presented with increasing headache and altered sensorium. It is noticed that vasospasm following subarachnoid haemorrhage has a typical course, which has increasing trend after 4th day of subarachnoid haemorrhage and declining trend after 14th day onwards. Six out of 12 patients were in moderate grade of vasospasm, 2 out of 12 were in severe grade and 4 out of 12 were mild grade of severity.