Cervical Blood Flow Research Articles

Association of the key immunological and hemodynamic determinants with cervix ripening in pregnant women.

Aim: To investigate a correlation between cervical ripening, the immunological features and the hemodynamic characteristics of the cervix during the preparation for vaginal labor. Materials and Methods: We examined 75 pregnant women at different gestational age. General clinical and immunological studies were conducted in order to check serum concentration of cytokines IL-6, IL-1β, and TNF-α. Ultrasound and Doppler study were used to determine resistance index and systolic-diastolic ratio of blood flow in the common uterine artery as well as the descending and ascending parts and cervical stromal arteries. Results: Pregnant women with high cervical ripening score had high concentrations of the major proinflammatory cytokines (IL-1β, IL-6, and TNF-α). Analysis of the of the cervical blood flow indicators of the studied groups showed significant differences in the indices of vascular resistance in the vessels that feed the cervix. Our data showed a significant correlation between the cervix ripening and both the serum levels of the studied cytokines and the level of peripheral vascular resistance indices in the common uterine arteries of the cervix, and the blood flow indices in the cervical stromal vessels. Conclusions: Our study shows that the process of preparing the woman's body for labor is associated with immunological adjustment and increased hemodynamics of the cervix. We report that cervical ripening is associated with the immunological components and hemodynamic parameters of the cervix at late-stage pregnancy. Measuring cervix ripening and the accompanied changes in cytokine levels and hemodynamic parameters will form a more accurate assessment of birth preparedness and labor complications.

Cerebral hemodynamic response to generalized anxiety disorder

BackgroundGeneralized anxiety disorder (GAD) is the least studied among anxiety disorders. Therefore, we aimed to compare the cervical blood flow velocities using doppler ultrasonography in untreated chronic GAD patients and healthy individuals. Material and MethodsIn this study, thirty-eight GAD patients were enrolled. And thirty-eight healthy volunteers were recruited as control participants. The common carotid artery (CCA), internal carotid artery (ICA), and vertebral artery (VA) of both sides were explored. Also, we trained machine learning models based on cervical arteries characteristics to diagnose GAD patients. ResultsPatients with chronic untreated GAD showed a significant increase in peak systolic velocity (PSV) bilaterally in the CCA and the ICA (P value < 0.05). In GAD patients, the end-diastolic velocity (EDV) of bilateral CCA, VA, and left ICA was significantly decreased. The Resistive Index (RI) showed a significant increase in all patients with GAD. Moreover, the Support Vector Machine (SVM) model showed the best accuracy in identifying anxiety disorder. ConclusionGAD is associated with hemodynamic alterations of extracranial cervical arteries. With a larger sample size and more generalized data, it is possible to make a robust machine learning-based model for GAD diagnosis.

The state of blood flow of the main arteries of the head in children with neurocirculatory dysfunction and connective tissue dysplasia

BACKGROUND: The article studies the relationship between connective tissue dysplasia and neurocirculatory dysfunction. They are united by a systematic and multi-organ nature of complaints and violations. The frequency of occurrence of neurocirculatory dysfunction in connective tissue dysplasia depends on the severity of phenotypic signs and is 23.531.1%.&#x0D; AIM: The aim of this study is to evaluate the significance of the method of duplex scanning of the main cerebral vessels, as well as to evaluate the relationship of the obtained parameters with the data of neurosonography, radiography of the cervical spine in children with signs of neurocirculatory dysfunction and connective tissue dysplasia.&#x0D; MATERIALS AND METHODS: The duplex scanning method was used to study the main vessels of the neck that provide blood supply to the brain: common and internal carotid, vertebral arteries in 240 children hospitalized for somatic various diseases.&#x0D; RESULTS: The presence of diagnostically significant changes in the cervical spine was found in 111 of them (46.3%): hypoplasia of the CI or СII vertebrae with cranial subluxations, instability of the cervical spine, and juvenile osteochondrosis. In children diagnosed with neurocirculatory dysfunction without signs of connective tissue dysplasia, disturbances in the form of asymmetry of blood flow along the entire vertebral artery prevail in comparison with the comparison group. In patients with more pronounced signs of connective tissue dysplasia, structural features of the cervical spine (hypoplasia of the CI or СII vertebrae with cranial subluxations, instability, juvenile osteochondrosis) and impaired blood flow of the main arteries are significantly more common.&#x0D; CONCLUSIONS: According to the data of duplex scanning of the main arteries of the neck, disorders in the form of hemodynamically significant asymmetry of blood flow in the vertebral arteries at different levels are significantly more common. In patients with pronounced signs of connective tissue dysplasia, structural features of the cervical spine and impaired blood flow of the main arteries of the neck are significantly more common. The presence of connective tissue dysplasia may be one of the causes of the above disorders.

Early Warning Model of Placenta Accreta Spectrum Disorders Complicated with Cervical Implantation: A Single-Center Retrospective Study.

Background Placenta accreta spectrum (PAS) disorders seriously threaten the safety of the mother and infant in the perinatal period. Moreover, PAS is associated with poor maternal and perinatal outcomes once complicated with cervical implantation. Dismally, there are few reports about PAS complicated with cervical involvement currently, and the early warning models are also rarely reported. To screen the risk factors of PAS complicated with cervical implantation and construct an early risk warning model, we performed the analysis of clinical indicators and images of PAS patients by artificial intelligence (AI) data processing methods. Methods The clinical data of 166 patients with PAS in our hospital from January 2016 to September 2020 were retrospectively analyzed. The patients were divided into cervical implantation group and lower uterine implantation group according to the position of placenta implantation. Then, we compared the pregnancy outcomes of the two groups, screened the possible related factors of PAS complicated with cervical implantation by univariate analysis, and established the early warning model by logistic regression analysis. Results The maternal outcome of PAS complicated with cervical implantation was worse than that of the lower uterine implantation group. Through univariate analysis and logistic regression analysis, we found that the cervical width, abundant cervical blood flow, and bladder line interruption were all risk factors of PAS complicated with cervical implantation, and their contribution to the establishment of the regression model was statistically significant. Conclusion PAS complicated with cervical implantation was extremely severe. Early identification of risk factors and establishment of a risk warning model have certain guiding significance for clinical formulation of a reasonable treatment plan.

Rotational Vertebrobasilar Insufficiency: Is There a Physiological Spectrum? Phase-Contrast Magnetic Resonance Imaging Quantification in Healthy Volunteers

BackgroundSome cases of cerebral ischemia have been attributed to dynamic flow limitation in neck vessels. It however remains unknown whether this represents the extreme end of a physiological response. MethodsEighteen healthy volunteers were recruited to this prospective study. Cervical blood flow (ml/min/m2) was assessed using phase-contrast MRI, and cerebral perfusion ratios were assessed using arterial spin labeling perfusion at neutral position, predefined head rotations, as well as flexion and extension. Inter-reader agreements were assessed using intraclass correlation coefficient. ResultsThe mean age was 38.6 ± 10.8 (range = 22-56) years, for five male participants and 13 females. The means for height and weight were 168 cm and 73.2 kg, respectively. There were no significant differences in individual arterial blood flow with change in head position (P > 0.05). Similarly, the repeated-measures analysis of variance test demonstrated no significant difference in perfusion ratios in relation to head position movement (P > 0.05). Inter-reader agreement was excellent (intraclass correlation coefficient = 0.97). ConclusionsThere is neither significant change in either individual cervical arterial blood flow nor cerebral perfusion within the normal physiological/anatomical range of motion in healthy individuals. It is therefore reasonable to conclude that any such hemodynamic change identified in a patient with ischemic stroke be considered causative.

Impact of Cervical Collar and Patient Position on the Cerebral Blood Flow

Background: Spinal protection during emergency medical service (EMS) transport after trauma has become a focus of debate. Historically, patients at risk for spine injury are transported in a rigid collar, long spineboard and headblocks. The cervical collar (c-collar) is hypothesized to provide stabilization for the cervical spine. However, little is known how the c-collar affects cervical blood flow. Methods: Cerebral blood flow was measured in multiple conditions using a non-invasive cerebral blood flow monitor to establish cerebral blood flow index (CBFI). The CBFI data were collected at: standing, sitting, 45°, 30°, 10° or 15°, and supine, with and without c-collar. Descriptive statistics were used for CBFI in each condition, and parametric statistical methods were utilized to determine the significance of changes in CBFI. Results: Five volunteers were recruited, and each tested in six positions with and without c-collar. Mean age was 49 (standard deviation (SD) 15) years and 60% were male. The CBFI mean of means was 71.0 with and 69.4 without the c-collar. Only one subject demonstrated a statistically significant difference in CBFI with c-collar. The CBFI mean of means for position was 72.6 for head of bed less than 30° and 68.1 for greater than 30°. All subjects demonstrated > 99% confidence for a statistically significant difference in CBFI when dichotomized using head of bed at 30°. Conclusions: Head of the bed position has greater influence on CBFI than the c-collar . Clinical significance in healthy volunteers is unknown but this change in cerebral blood flow may have clinical significance in traumatic brain injury or neurologic conditions that compromise autoregulation. J Neurol Res. 2020;10(5):177-182 doi: https://doi.org/10.14740/jnr611

Impact of Cervical Collar and Patient Position on the Cerebral Blood Flow

Background: Spinal protection during emergency medical service (EMS) transport after trauma has become a focus of debate. Historically, patients at risk for spine injury are transported in a rigid collar, long spineboard and headblocks. The cervical collar (c-collar) is hypothesized to provide stabilization for the cervical spine. However, little is known how the c-collar affects cervical blood flow. Methods: Cerebral blood flow was measured in multiple conditions using a non-invasive cerebral blood flow monitor to establish cerebral blood flow index (CBFI). The CBFI data were collected at: standing, sitting, 45°, 30°, 10° or 15°, and supine, with and without c-collar. Descriptive statistics were used for CBFI in each condition, and parametric statistical methods were utilized to determine the significance of changes in CBFI. Results: Five volunteers were recruited, and each tested in six positions with and without c-collar. Mean age was 49 (standard deviation (SD) 15) years and 60% were male. The CBFI mean of means was 71.0 with and 69.4 without the c-collar. Only one subject demonstrated a statistically significant difference in CBFI with c-collar. The CBFI mean of means for position was 72.6 for head of bed less than 30° and 68.1 for greater than 30°. All subjects demonstrated &gt; 99% confidence for a statistically significant difference in CBFI when dichotomized using head of bed at 30°. Conclusions: Head of the bed position has greater influence on CBFI than the c-collar . Clinical significance in healthy volunteers is unknown but this change in cerebral blood flow may have clinical significance in traumatic brain injury or neurologic conditions that compromise autoregulation. J Neurol Res. 2020;10(5):177-182 doi: https://doi.org/10.14740/jnr611

OS 25-04 THE CHANGES OF ARTERIAL STIFFNESS MONITORED WITH CARDIO ANKLE VASCULAR INDEX (CAVI) DURING RAISED INTRACRANIAL PRESSURE IN THE RABBIT

Objective: Cardio ankle vascular index (CAVI) is reflecting stiffness of the arterial tree from the origin of aorta to the ankles. We observed elevated CAVI in patients who suffered from apoplexy attack. To clarify the role and the mechanism by which arterial stiffness elevated just after apoplexy attack, the effect of enhanced intracranial pressure (ICP) by injecting saline into the cisterna magna of the rabbit on blood pressure, CAVI and cervical blood flow, were studied. Furthermore the role of sympathetic nerve was studied. Design and Method: The system of measuring CAVI of the New Zealand white rabbit was set up. General anesthesia was performed by ketamine and xylazine, and the respirator was set. Intracranial pressure (ICP) was monitored using a catheter inserted into subarachnoid space via right frontal bone craniotomy. Saline (15 ml) was inserted to raise ICP. Ganglion blocker, hexamethonium (10 μg/kg/10 min, and 100 μg/kg/10min) was administered just before saline injection. Results: When saline was injected into the cisterna magna and ICP was raised over 20 mmHg at least, blood pressure (62 ± 7.43 → 135 ± 27.41 mmHg), and CAVI (3.3 ± 0.39 → 4.8 ± 0.89) were increased. The heart rate and blood flow of common carotid artery increased. When hexamethonium (10 μg/kg/10 min and 100 μg/kg/10min) was administered before raising ICP, enhanced IPP -induced blood pressure increase (123 ± 9.58, 90 ± 5.42 mmHg, respectively) and CAVI increase (4.3 ± 0.35, 4.0 ± 0.16, respectively) were inhibited dose-dependently. Conclusions: Raised ICP induced an increase of blood pressure accompanying with an increase of CAVI, suggesting that enhanced stiffness of muscle artery might partly induce high blood pressure. Blocking sympathetic nerve by hexamethonium diminished raised blood pressure and CAVI, indicating that ICP increase-induced blood pressure and CAVI increases were mediated by sympathetic nerve activation.

Cervical vertigo related cerebral blood flow change revealed by three dimensional pseudo continuous arterial spin labeling

Objective To quantitatively investigate the change of cerebral blood flow (CBF)induced by cervical vertigo by using 3D pseudo-continuous arterial spin labeling (3D PCASL).Methods This study included 17 patients without cerebral arterial stenosis on MRA as the patient group and 14 healthy volunteers as the control group.They were examined by 3D PCASL before and after the vertigo-inducing test respectively.CBF was measured in regions of interest (ROI) which were perfused by bilateral anteroinferior cerebellar artery (AICA),posteroinferior cerebellar artery (PICA),superior cerebellar artery (SCA),posterior cerebral artery (PCA),middle cerebral artery (MCA),anterior cerebral artery (ACA) and posterior pons.The change of CBF caused by the vertigo-inducing test was calculated for every ROI.Independent t test was used to compare the change of CBF between the patients and controls.Results There was significant difference of change of CBF in the ROIs of R-PICA,R-AICA,R-ACA,bilateral SCA,bilateral PCA territory and posterior pons between the patients and controls (t =2.30 to 3.99,P ＜ 0.05).CBF values in these ROIs were significantly decreased after the vertigo-inducing test in the patients.The changes of CBF in ROIs of patients and controls were as following:(1) R-PICA (-3.86 ± 6.43) vs.(0.63 ±4.37) ml/(min · 100 g) ; (2) R-AICA (-4.30 ±6.79) vs.(0.39 ±3.51) ml/(min · 100 g) ;(3) SCA:(-7.15 ±6.70) vs.(-0.27 ±3.89) ml/(min · 100 g) for the left side,(6.99 ±6.34) vs.(-0.68±3.18) ml/(min · 100 g) for the right side; (4) PCA:(-7.39 ±6.31) vs.(-0.39 ±3.24) ml/(min· 100g) for the left side,(-7.86±6.48) vs.(-1.41±2.91) ml/(min· 100 g) for the right side; (5) R-ACA (-3.50 ±4.03) vs.(0.16 ±3.07) m]/(min · 100 g) ; (6) posterior pons (-5.91 ±7.34) vs.(0.06 ± 3.41) ml/(min · 100 g).Conclusions 3D PCASL is able to detect the CBF change induced by vertigo-inducing test.Cervical vertigo onset is related to posterior circulation ischemia,which may be caused by the spinal position changes. Key words: Vertigo; Cervical spondylosis; Magnetic resonance imaging

Hemodynamic influence of arteria vertebralis type cervical spondylosis treated by needling Yuzhen (BL 9) and Fengchi (GB 20)

To observe the curative effect and the hemodynamic change of cervical vertigo treated by acupuncture, 66 patients were randomly divided into two groups: group A in which acupoints Yuzhen (BL 9) and Fengchi (GB 20) were used and Group B in which Cervical Jiaji points (C4–6) were used. Before and after treatment, the symptom of the cervical vertigo and the grade variety of function and the change of Color Doppler Flow Imaging (CDFI) of vertebral artery were observed. After treatment, the grade in two groups increased, there was a remarkable difference between two groups (P<0.05); after treatment, the grade of vertigo degree increased, there was a remarkable difference between two groups (P<0.05); needling Yuzhen (BL 9) and Fengchi (GB 20) can remarkably improve the symptom of cervical vertigo and vertebral artery blood flow rate, and the curative effect was superior to needling Jiaji points.

Pain, dizziness, and central nervous system blood flow in cervical extension: vascular correlations to beauty parlor stroke syndrome and salon sink radiculopathy.

Professional shampoos have previously been implicated in beauty parlor stroke syndrome and salon sink radiculopathy. The purpose of this study was to record pain, dizziness, and cervical blood flow while subjects were specifically placed into the salon sink position and to determine whether an additional cervical support would alter these symptoms and measurements. In 25 volunteers who reported previous dizziness from salon shampoos, we recorded subjective levels of pain and dizziness and objective measurements of blood flow within the vertebral and carotid arteries at baseline and then during cervical extension into a salon sink, with and without additional cervical support. When the additional cervical support was not used, there was significantly greater dizziness, neck pain, and carotid blood flow. No statistically significant differences were seen in the vertebral artery blood flow when comparing the three positions. Pain and dizziness were commonly reproduced in this previously symptomatic population but significantly less frequently when a supplemental cervical support was used. Individuals with a history of such symptoms should probably exercise caution when deciding whether to receive a salon sink shampoo.

Effect of Human Chorionic Gonadotropin on Reproductive Organ Blood Flow in Cycling Rats

Recent characterization of luteinizing hormone++ (LH)/human chorionic gonadotropin (hCG) receptors in uterine vascular tissue, evidence that expression of these receptors is cyclic in nature, and demonstration of a correlation between hCG level and uterine vascular resistance lead us to investigate the effect of hCG administration on blood flow in reproductive organs of cycling and ovariectomized Sprague-Dawley rats. Blood flow (ml/min/g dry wt/cardiac output +/- SEM) was determined by microsphere spectroscopy (57Co, 113Sn, 95Nb, 141Ce). Baseline uterine (0.5842 +/- 0.1037) and cervical (0.7785 +/- 0.1199) blood flows were greater in diestrus-2 rats than in every other group. Diestrus-2 (0.4530 +/- 0.0584) and estrus (0.4692 +/- 0.0848) rats had greater baseline ovarian blood flow than proestrus rats (0.2521 +/- 0.0279). A single intraperitoneal injection of 50 IU hCG on each day of the 4-day estrus cycle decreased uterine flow by more than 30% within 20 min (P<0.05), but did not alter uterine flow in ovariectomized rats. This dose of hCG also decreased ovarian flow in diestrus-2 rats (0.5219 +/- 0.0857 to 0.4207 +/- 0.0753), decreased liver flow in diestrus-2 (0.0282 +/- 0.0060 to 0.0231 +/- 0.0051) and estrus (0.0301 +/- 0.0029 to 0.0203 +/- 0.0038 rats, and increased liver flow in ovariectomized rats (0.0279 +/- 0.0054 to 0.0325 +/- 0.0050). Injection of 0.10 IU hCG did not alter blood flow to reproductive organs in any group, but decreased liver flow in estrus rats (0.0469 +/- 0.0121 to 0.0326 +/- 0.0088). Neither dose of hCG altered cervical, kidney, or skeletal muscle flow in any group. Our results indicate an organ specific, dose-dependent blood flow response to hCG in cycling rats, which appears, in the case of uterine flow, to be attenuated by removal of the ovaries. The present findings suggest high doses of hCG given clinically may decrease uterine flow and potentially lead to implantation failure.

Characterization of placenta accreta using transvaginal sonography and color Doppler imaging.

The safe use of transvaginal sonography in patients with placenta previa has been confirmed, and has revolutionized precise placental localization. The aim of our study was to evaluate the efficacy of transvaginal sonography and color-coded blood flow in the prediction of placenta accreta. Twenty-one patients with persistent placenta previa were scanned using transvaginal sonography and color-coded flow. Suspicion for placenta accreta consisted of total placenta previa at term with several placental lacunae exhibiting marked or turbulent blood flow, as seen with color Doppler transvaginal sonography from within the placenta, extending into the surrounding tissues. Five of the patients exhibited sonographic placental patterns suspicious for placenta accreta and one patient exhibited placental and cervical blood flow described as lacunar. Five Cesarean hysterectomies were performed for placenta accreta. Every placenta accreta was correctly diagnosed sonographically by the use of color flow studies. One patient with suspicion of placenta accreta delivered at another institution, a Cesarean hysterectomy was performed, and the pathology was confirmed. The one placenta previa exhibiting turbulent lacunar flow in the cervical area only was not confirmed to be an accreta at Cesarean section, although hemostasis was difficult at the placental bed. The remaining 15 patients with placenta previa and who on sonography were not suspicious for placenta accreta underwent uncomplicated Cesarean section. Transvaginal sonography and color Doppler imaging improve the diagnostic accuracy in the prediction of placenta accreta in patients with persistent placenta previa. A pattern of turbulent blood flow extending from the placenta into the surrounding tissues should alert the physician to the possibility of placenta accreta.

Effects of some neurotransmitters and prostanoids on isolated human intracervical arteries

Human cervical tissue specimens were excised after hysterectomy at various phases of the menstrual cycle (n = 12), and small intracervical arteries were dissected free by microtechnique. Ring preparations of the vessels were prepared and mounted in organ baths, and isometric circular tension was recorded. Norepinephrine, 3 × 10−8 to 10−5 mol/L, produced concentration-dependent contractions, whereas 3 × 10−7 to 10−6 mol/L prostaglandin F2α inconsistently produced weak contractions and slightly increased tension induced by 10−5 mol/L norepinephrine. Prostaglandin I2, 10−9 to 10−6 mol/L, prostaglandin E2, 3 × 10−9 to 10−6 mol/L, vasoactive intestinal polypeptide, 10−9 to 10−7 mol/L, and substance P, 10−12 to 10−9 mol/L, induced relaxation of vessels precontracted by 10−5 mol/L norepinephrine. It is suggested that several mechanisms for the local release of vasoactive compounds may influence cervical blood flow. Thus, sympathetic control of cervical blood flow may be modulated by peptide neurotransmitters such as vasoactive intestinal polypeptide and substance P and by local synthesis of prostaglandins E2 and I2.

Effects of Human Calcitonin Gene-Related Peptide and Substance P on Human Intracervical Arteries

The contractile effects of substance P and human calcitonin gene-related peptide (human CGRP) on isolated human intracervical arteries were studied. Human cervical tissue specimens were excised after hysterectomy at various phases of the menstrual cycle (n = 14) and small intracervical arteries were dissected free by microtechnique. Ring preparations of the vessels were prepared and mounted in organ baths, and isometric circular tension was recorded. Neither compound affected resting tension. Both peptides showed potent relaxing effects on vessels precontracted by noradrenaline 10(-5) M. Substance P exhibited the higher potency, while human CGRP showed the higher efficacy. The relaxing effects of the two compounds were unaffected by pretreatment with indomethacin 10(-6) M, propranolol 10(-6) M and atropine 10(-6) M. The results support a role for the two peptides in the regulation of cervical blood flow.

Prostaglandin E 1 increases blood flow to the cervix uteri

PGE 1 occurs in high concentration in seminal fluid and is apparently necessary for normal fertility, although its specific function(s) is not known. We investigated the possibility that PGE 1, at seminal fluid concentration, could increase cervical blood flow and, thus, potentially alter cervical mucus properties, including 0 2 concentration. Fifteen μg PGE 1/ml placed directly on the cervix uteri increased cervical blood flow in anesthetized dogs from 0.8±0.7 to 5.7±5.1 ml/gomin 5 min following application without affecting arterial pressure or hepatic or renal blood flow. Seminal PGE 1 may have effects upon oxygen tension in the cervical mucus, as well as aiding leukocyte accumulation in the cervical canal, by increasing cervical blood flow.

THE EFFECT OF SYSTEMIC INFUSIONS OF DEHYDROISOANDROSTERONE (D) ON THE DISTRIBUTION OF UTERINE BLOOD FLOW (UBF) IN THE OVINE PREGNANCY

Although estrogen is a potent vasodilator of the vascular beds of the ovine uterus, precursors of ovine estrogen remain unknown. Studies in our laboratories have shown increases in UBF and plasma estrone (E1) and eatradiol (E2) after systemic infusions of D in the pregnant ewe. To investigate the distribution of UBF after the infusion of 6 mg D, 4 pregnant ewes, 105 to 128 days of gestation, were studied with microspheres. Serial blood samples from 3 ewes showed increases at 15 min in E1 from 27.3±2.23 (mean ± SE) to 117 ± 13.2 pg/ml and in E2 from 34.3 ± 4.91 to 71.7 ± 5.21 pg/ml (p ≤ 0.05). At 140 min neither UBF nor placental blood flow was significantly altered. Endometrial blood flow increased from 176 ± 24 to 242 ± 32 ml/min (39%, P < 0.005) and myometrial blood flow rose from 35 ± 6.1 to 51 ± 8.4 ml/min (45%, p < 0.01). Mammary gland blood flow also rose. Of particular interest were the responses in cervical blood flow, rising from 3.18 ± 0.6 to 15.6 ± 2.0 ml/min (441%, p < 0.005), and vaginal blood flow from 0.175 ± 0.03 to 0.992 ± 0.15 ml/min·gm (476%, p < 0.01). These studies suggest that D may be an important estrogen precursor and the ovine estrogen surge observed at term may prepare the mammary, uterus, cervix and vagina for the process of parturition. Furthermore, the increase in UBF following an infusion of D reflects increased perfusion of non-placental tissues, supporting earlier observations that exogenous estrogen administration might have no beneficial effects for the fetus.

Changes in the cervical blood flow during labour.

The cervical blood flow changes during labour in pregnant women (15 cases) have been studied by local injection of 133Xe into the cervix. The blood flow changes were compared with the external uterine pressure which was measured with a tocograph. During contractions the radioactivity decreased temporarily, but increased again between contractions. The overall decrease was greater in the control group (4 cases) than during spontaneous contractions. The conclusion is, that relative cervical blood circulation is rapidly changed during labour.

The effect of radium on blood flow in the human uterine cervix measured by local hydrogen clearance.

Abstract. Cervical blood flow was measured by the local hydrogen gas clearance method in 15 patients with untreated carcinoma of the uterine cervix and in 16 patients six to eight weeks after radium irradiation. Mean cervical blood flow was 75.5 ml/min. 100 g in the untreated group and 92.4 ml/min. 100 g in the treated group.

The Effect of Oxytocin on Human Uterine Blood Flow Measured by Local Hydrogen Clearance

Abstract. Local myometrial and cervical uterine blood flow were measured repeatedly in 45 women by the hydrogen gas clearance method. Mean myometrial blood flow in the postmenopausal women was 57.5 ± 6.67 ml/min. 100 g and in the women of fertile age 105.5 ± 8.36 ml/min. 100 g. When oxytocin was given intravenously between measurements, no effect on myometrial blood flow was obtained in the postmenopausal women. In women of fertile age, myometrial blood flow was reduced to 18.9 ± 5.08% of controls in the proliferative phase and to 33.1 ± 7.62% in the secretory phase 2 minutes after injection of oxytocin, whereas cervical blood flow in both phases showed no or only a slight reduction.