Tomihiro Katayama

Immunoneutralization of Glycoprotein Ibα Attenuates Endotoxin-Induced Interactions of Platelets and Leukocytes With Rat Venular Endothelium In Vivo

This study aimed to examine molecular mechanisms for endotoxin-induced adhesive changes in platelets in vivo. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester were visualized in rat mesenteric venules through intravital microscopy assisted by a high-speed fluorescence video imager at 1000 frames per second or by a normal-speed intensifier under monitoring of erythrocyte velocity. Leukocyte rolling was examined by normal-speed transmission video images. The velocity of platelets traveling along the centerline of venules followed that of erythrocytes, whereas that measured at the periendothelial space was significantly smaller than the erythrocyte velocity; a majority of these cells exhibited transient but notable rolling with endothelium. Administration of endotoxin increased the density of periendothelial platelets and reduced the rolling velocities of platelets and leukocytes in venules: All events were attenuated by anti-rat P-selectin monoclonal antibody s789G or by anti-human glycoprotein (GP) Ibalpha monoclonal antibody GUR83/35, which blocks ristocetin-induced aggregation of rat platelets. Isolated rat platelets injected into endotoxin-pretreated rats were able to roll on the venules. This event was attenuated by pretreatment of platelets in vitro with GUR83/35 but not with s789G, suggesting involvement of endothelial P-selectin and platelet GP Ibalpha in the endotoxin-induced responses. Furthermore, isolated human platelets showed similar rolling interactions with endotoxin-preexposed rat venules, and pretreatment of the platelets with GUR83/35, but not with s789G, significantly reduced such interactions. Our results provide the first evidence for involvement of GP Ibalpha in endotoxin-induced microvascular rolling of platelets and leukocytes, and this system serves as a potentially useful tool to examine GP Ibalpha-associated function of human platelets in vivo.

Effect of dienogest administration on angiogenesis and hemodynamics in a rat endometrial autograft model

BACKGROUND We aimed to establish an endometrial autograft model in rats that would allow for repetitive in vivo analyses of angiogenesis. Dienogest (DNG) is an orally active progestin used for the treatment of endometriosis. We investigated whether DNG would affect angiogenesis of the ectopic endometrium in our model. METHODS Mechanically isolated endometrial fragments were transplanted into dorsal skinfold chambers in rats. We analyzed the effect of DNG on angiogenesis of the ectopic endometrium on Days 0, 2, 4, 7, 10 and 14 after transplantation using intravital fluorescence microscopy. RESULTS The DNG-administered group showed significant suppression of angiogenesis of endometrial autografts, as indicated by the reduced size of the microvascular network and decreased microvessel density compared with those of control animals. The newly formed microvessels of the DNG-administered group showed consistently elevated diameters and centerline red blood cell velocity was decreased. Immunohistochemistry revealed a significant reduction in the level of perivascular α-smooth muscle actin within endometrial grafts of the DNG-administered group. CONCLUSIONS DNG inhibited angiogenesis of the ectopic endometrium, with confirmed structural changes in the microvessels.

Carbon monoxide modulates endotoxin-induced microvascular leukocyte adhesion through platelet-dependent mechanisms

BACKGROUND Although precise mechanisms remain to be determined, recent studies show that heme oxygenase-1 (HO-1), providing endogenous carbon monoxide (CO) and bilirubin, serves as an antiinflammatory enzyme. This study aimed to clarify roles of CO in regulation of microvascular adhesion of platelets and leukocytes in endotoxemia. METHODS Rats pretreated with or without hemin were anesthetized with pentobarbital and received continuous infusion of endotoxin. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester and leukocyte behavior in mesenteric venules were visualized using intravital ultra-high-speed intensified fluorescence videomicroscopy. To examine the mechanisms for the effects of HO-1 on platelet and leukocyte behavior during endotoxemia, these studies were repeated with superfusion of either CO, bilirubin, or zinc protoporphyrine-IX. RESULTS Endotoxin caused a marked depression of platelet velocity traversing along periendothelial regions, accompanied by augmented rolling and adhesion of leukocytes in venules. The endotoxin-elicited changes were attenuated by the HO-1 induction with hemin and restored by blockade of the enzyme activity with zinc protoporphyrine-IX, a potent inhibitor of HO-1. Such an inhibitory action of HO-1 on microvascular cell adhesion was reproduced by local superfusion of the buffer containing CO at micromolar concentrations. Such antiadhesive actions of CO on leukocytes disappeared under immunoneutralization of glycoprotein Ibalpha, an adhesion molecule against platelets, but not against leukocytes. Platelets isolated from hemin-treated rats increased their ability to generate CO and displayed lesser sensitivity of agonist-induced aggregation than those from controls. CONCLUSIONS These results suggest that CO desensitizes endotoxin-induced adhesive responses of leukocytes, mainly through its ability to ameliorate platelet activation.

Roles of carbon monoxide in leukocyte and platelet dynamics in rat mesentery during sevoflurane anesthesia

BackgroundHeme oxygenase 1 (HO-1), induced by a variety of stressors, provides endogenous carbon monoxide (CO) and bilirubin, both of which play consequential roles in organs. The current study aimed to examine whether induction of HO-1 and its by-products modulated endothelial interaction with circulating leukocytes and platelets evoked by sevoflurane anesthesia in vivo. MethodsRats, pretreated with or without hemin, were anesthetized with sevoflurane in 100% O2, and lungs were mechanically ventilated. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester and leukocyte behavior in mesenteric venules were visualized during sevoflurane anesthesia at 1,000 frames/s using intravital ultrahigh-speed intensified fluorescence videomicroscopy. To examine the mechanisms for the effects of HO-1 on leukocyte and platelet behavior, these studies were repeated with superfusion of either CO, bilirubin, or N&ohgr;-nitro-l-arginine methyl ester (l-NAME). ResultsAs reported previously, the elevation of sevoflurane concentration evoked adhesive responses of leukocytes, concurrent with platelet margination and rolling. Pretreatment with hemin, a HO-1 inducer, prevented such sevoflurane-elicited changes in the microvessels. These changes were restored by zinc protoporphyrin IX, a HO inhibitor, and repressed by CO but not by bilirubin. During sevoflurane anesthesia, however, nitric oxide suppression by l-NAME deteriorated microvascular flows irrespective of the presence or absence of the HO-1 induction. ConclusionsThese results indicate that endogenous CO via HO-1 induction attenuates sevoflurane-induced microvascular endothelial interactions with leukocytes and platelets, although local nitric oxide levels appear to dominate microvascular flow in situ.

Prenatal diagnosis of Berry syndrome by fetal echocardiography

A healthy 26-year-old woman, gravida 3 para 2, was seen at 22 weeks’ gestation for a second-trimester ultrasound examination. She had no significant medical history and had had a normal pregnancy up to this point. Ultrasound examination revealed a medial homogeneous mass protruding from the chin of a female fetus. Color-flow mapping showed no vascularization, and no other abnormality was detected. Two-dimensional (Figure 1) and three-dimensional (3D) (Figure 2) ultrasound examination at 33 weeks’ gestation showed the tumor to have a maximum diameter of 3 mm and a length of 6 mm. A thorough magnetic resonance imaging (MRI) examination of the fetal brain performed at 35 weeks of amenorrhea, aiming to accurately visualize the fetal midline cerebral structures, showed no abnormality. The infant was delivered vaginally at 39 weeks’ gestation, and weighed 3335 g. Clinical examination of the neonate was normal other than the presence of a 6-mm tag-like skin-covered mass situated on the median part of

The Influence of the Maternal Heart Rate on the Uterine Artery Pulsatility Index in the Pregnant Ewe

We investigated the influence of the maternal heart rate on the uterine artery pulsatility index in pregnant ewes. We used an external pacemaker to alter the heart rate of 5 pregnant ewes at 16–17 weeks of pregnancy and examined the effect of changes in the maternal heart rate on the uterine artery flow velocity waveforms and the pulsatility index, as determined by Doppler velocimetry. The uterine artery pulsatility index showed a significant negative correlation with the maternal heart rate. There were no significant changes in other hemodynamic parameters. The maternal heart rate had a significant influence on the uterine artery pulsatility index.

Ranking the contributing risk factors in venous thrombosis in terms of therapeutic potential : Virchow's triad revisited

Aim:  Thromboemoblism is an attendant feature of a variety of pathological conditions. We reconsidered Virchows pathogenetic triad of stasis, humoral factors and vascular wall pathologies in the light of platelet behavior in vivo.

Clinical significance of normalization of uterine artery pulsatility index with maternal heart rate for the evaluation of uterine circulation in pregnancy-induced hypertension.

To investigate whether the use of normalized pulsatility index (PI) improves evaluation of the fetal prognosis in pregnancy‐induced hypertension (PIH).

Nitric oxide production and blood corpuscle dynamics in response to the endocrine status of female rats

INTRODUCTION Menopause is associated with marked changes in the endocrine profile, and increases the risk of vascular disease. However, the effect of hormones on the vascular system is still unclear. Therefore, the aim of this study was to examine the effects of endocrine status in female rats on nitric oxide (NO) production, inflammatory reactions and thrombus organization potency in the mesenteric microcirculation. MATERIALS AND METHODS Female Wistar rats were divided into four groups: proestrus, metestrus, ovariectomized (OVX) and OVX plus estradiol treatment (OVX+E2). NO was imaged using an NO-sensitive dye. The leukocyte and platelet velocities relative to the erythrocyte velocity (VW/VRC and VP/VRE, respectively) and thrombi sizes created by laser radiation were measured as thrombogenesis indices. RESULTS Changes in endocrine status did not affect vascular function in the arterioles. However, in venules, NO production, VW/VRC and VP/VRE were decreased in the OVX group compared with the proestrus and metestrus states. Thrombus size was significantly greater in the OVX group than in the proestrus and metestrus states. Administration of E2 for 2 weeks restored NO production, VW/VRC and VP/VRE to control levels. CONCLUSIONS Changes in endocrine status did not affect arterioles. In contrast, in venules, reduced estrogen levels led to a decrease in NO production, thereby increasing thrombogenesis. Estrogen replacement restored NO production and leukocyte and platelet velocities, reducing thrombus formation relative to OVX. Although it is unclear how E2 reduces thrombus formation, our results indicate that leukocyte and platelet adhesion to the endothelium is a target for E2 via NO.

Diagnosis and treatment of Wunderlich syndrome

Wunderlich syndrome is a rare Mullerian anomaly consisting of uterine didelphy, cervical cyst, and ipsilateral renal agenesis [1]. It is likely that the malformations occur from embryonic arrest at 8 weeks of gestation, at which point the adjacent Mullerian and metanephric ducts are simultaneously affected. This anomaly inhibits the outflow of menstruation and causes menstrual blood to pool in the uterus; however, it is often asymptomatic anddifficult to diagnose [2]. A healthy 15-year-old female who had experienced normal pubertal events underwent menarche. Three months after menarche, she complained of lower abdominal pain, especially after menstruation. She was of moderate stature, with normal external genitalia, and a regular menstrual cycle. She was diagnosed by magnetic resonance imaging (MRI) as having a double uterus with a right cervical cyst (Fig. 1). Intravenous pyelography demonstrated right renal agenesis with normal function and contour of the left renal collecting system (Fig. 1). The left cervix was intact and the right cystic wall was resected using an ultrasonic cutting and coagulating surgical device (Harmonic scalpel; Johnson & Johnson, New Brunswick, NJ, USA). She was diagnosed with Wunderlich syndrome since the resected tissue demonstrated cervical glands. The postoperative course was uneventful. A healthy 18-year-old female complained of intermittent purulent vaginal discharge since menarche. She underwent menarche at the age of 12 years and experienced normal pubertal events. She had a history of regular menses with increasing lower abdominal pain lasting 2–4 days during each menstrual cycle. She was ofmoderate stature with normal external genitalia. Abdominal ultrasonography demonstrated a small pelvic cystic mass; MRI demonstrated uterus didelphys with a left cervical cyst containing homogeneous fluid compatible with old blood. Intravenous pyelography demonstrated left renal agenesis. The left cystic wall was resectedusinganultrasonic cutting andcoagulating surgical device, andWunderlich syndromewas diagnosed. The postoperative period was uneventful. Hematocervix of Wunderlich syndrome is diagnosed when the ipsilateral hemiuterus and vagina are not connected. Differential diagnosis includes Herlyn–Werner syndrome, which consists of a renal agenesis and an ipsilateral blind hemivagina [3]. Gartners cysts of Herlyn–Werner syndrome can be pathologically differentiated from cervical cysts of Wunderlich syndrome. A Gartners cyst is a cystic remnant of the mesonephric ducts in the vaginal wall, while a cervical cyst demonstrates cervical glands. Common clinical presentations of both Herlyn–Werner syndrome and Wunderlich syndrome are pelvic pain and/or dysmenorrhea shortly after menarche, in association with a vaginal/pelvic mass. When the cyst and vagina are connected, symptoms of abnormal vaginal discharge and bleeding are common. Abdominal and pelvic MRI studies are necessary to confirm and characterize thedetails of uterinemalformation and renal anomaly. Treatment is to resect as much of the obstructing vaginal septum as possible. Errors in surgical management can occur when the diagnosis is incorrect, and laparotomy is performed to explore and resect the intra-abdominal mass. Although fertility is not compromised, spontaneous abortion rate is high. However, patients who carry pregnancy to term often have no obstetric difficulties. Prompt and accurate diagnosis, and subsequent excision of the obstructing vaginal septum, is required in patients with ⁎ Corresponding author. Ehime University School of Medicine, Shitsukawa, Toon, Ehime 791 0295, Japan. Tel.: +81 89 960 5379; fax: +81 89 960 5381. E-mail address: takeyu@m.ehime-u.ac.jp (Y. Matsubara).