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Featured researches published by Tomoyuki Kuwata.


Acta Obstetricia et Gynecologica Scandinavica | 2013

Uterine compression sutures for postpartum hemorrhage: an overview

Shigeki Matsubara; Hitoshi Yano; Akihide Ohkuchi; Tomoyuki Kuwata; Rie Usui; Mitsuaki Suzuki

In 1997, B‐Lynch pioneered the use of uterine compression sutures for postpartum hemorrhage. Since then, some researchers, including ourselves, have devised various uterine compression sutures. High‐level evidence has not been demonstrated as to whether compression sutures achieve better and safer hemostasis for postpartum hemorrhage than other methods, and, if they do, whether one suture is more efficient and safer than another. However, generally speaking, uterine compression sutures have achieved hemostasis while preserving fertility in many women and thus their efficacy and safety have been time‐tested. Each suture has both merits and drawbacks: obstetricians must be aware of the fundamental characteristics of various sutures. In this review, we summarize the technical procedures, efficacy, safety and complications of various uterine compression sutures. We add our own experiences and opinions where necessary.


Acta Obstetricia et Gynecologica Scandinavica | 2013

Important surgical measures and techniques at cesarean hysterectomy for placenta previa accreta

Shigeki Matsubara; Tomoyuki Kuwata; Rie Usui; Takashi Watanabe; Akio Izumi; Akihide Ohkuchi; Mitsuaki Suzuki; Manabu Nakata

For cesarean hysterectomy with placenta previa accreta, “universally achievable” measures are required. We propose eight measures: (i) placement of intra‐iliac arterial occlusion balloon catheters; (ii) placement of ureter stents; (iii) “holding the cervix” to identify the site to be transected; (iv) uterine fundal incision; (v) avoidance of uterotonics; (vi) “M cross double ligation” for ligating the ovarian ligament; (vii) “filling the bladder” to identify the bladder separation site and “opening the bladder” for placenta previa accreta with bladder invasion; and (viii) to continue to clamp the medial side of the parametrium or the cervix or employment of the “double edge pick‐up” to ligate it. These eight measures are simple, easy, effective, and thus “universally achievable”.


Biology of Reproduction | 2014

Human Exosomal Placenta-Associated miR-517a-3p Modulates the Expression of PRKG1 mRNA in Jurkat Cells

Saori Kambe; Hiroshi Yoshitake; Kazuya Yuge; Yoichi Ishida; Md. Moksed Ali; Takami Takizawa; Tomoyuki Kuwata; Akihide Ohkuchi; Shigeki Matsubara; Mitsuaki Suzuki; Toshiyuki Takeshita; Shigeru Saito; Toshihiro Takizawa

ABSTRACT During pregnancy, human placenta-associated microRNAs (miRNAs) derived from the miRNA cluster in human chromosome 19 are expressed in villous trophoblasts and secreted into maternal circulation via exosomes; however, little is known about whether circulating placenta-associated miRNAs are transferred into maternal immune cells via exosomes, and modulate expression of target genes in the recipient cells. We employed an in vitro model of trophoblast-immune cell communication using BeWo cells (a human trophoblast cell line) and Jurkat cells (a human leukemic T-cell line) and investigated whether BeWo exosomal placenta-associated miRNAs can suppress expression of target genes in the recipient Jurkat cells. Using this system, we identified PRKG1 as a target gene of placenta-associated miRNA miR-517a-3p. Moreover, we demonstrated that BeWo exosomal miR-517a-3p was internalized into Jurkat cells and subsequently suppressed the expression of PRKG1 in recipient Jurkat cells. Furthermore, using peripheral blood natural killer (NK) cells in vivo, we confirmed that circulating miR-517a-3p was delivered into maternal NK cells as it was into Jurkat cells in vitro. Placenta-associated miR-517a-3p was incorporated into maternal NK cells in the third trimester, and it was rapidly cleared after delivery. Expression levels of miR-517a-3p and its target mRNA PRKG1 were inversely correlated in NK cells before and after delivery. These in vitro and in vivo results suggest that exosome-mediated transfer of placenta-associated miRNAs and subsequent modulation of their target genes occur in maternal NK cells. The present study provides novel insight into our understanding of placenta-maternal communication.


Archives of Gynecology and Obstetrics | 2014

Uterine artery pseudoaneurysm: not a rare condition occurring after non-traumatic delivery or non-traumatic abortion

Yosuke Baba; Shigeki Matsubara; Tomoyuki Kuwata; Akihide Ohkuchi; Rie Usui; Miyuki Saruyama; Manabu Nakata; Mitsuaki Suzuki

PurposeUterine artery pseudoaneurysm (UAP) is considered a rare disorder after traumatic delivery or traumatic pregnancy termination such as cesarean section or dilatation and curettage, initially manifesting as genital hemorrhage. Our clinical impression contradicts these three assumptions; after traumatic delivery/termination, hemorrhage, and its rarity. Thus, we attempted to clarify these three issues.MethodsWe retrospectively analyzed 22 UAP cases treated at our institute over a 6-year period.ResultsUterine artery pseudoaneurysm occurred in 2–3/1,000 deliveries. Of 22 cases, half occurred after non-traumatic deliveries or non-traumatic pregnancy termination. Fifty-five percent (12/22) showed no hemorrhage; ultrasound or color Doppler revealed UAP. Thus, half of UAP occurred after non-traumatic deliveries or non-traumatic pregnancy termination and showed no hemorrhage at the time of their diagnoses. All patients received transarterial embolization, which stopped blood flow into UAP or achieved hemostasis.ConclusionWe must be aware that UAP may not be so rare and it may be present in patients after non-traumatic deliveries/pregnancy termination and without postpartum or postabortal hemorrhage.


Journal of Obstetrics and Gynaecology Research | 2010

Asymptomatic uterine artery pseudoaneurysm after cesarean section.

Tomoyuki Kuwata; Shigeki Matsubara; Yuka Kaneko; Akio Izumi; Manabu Nakata; Mitsuaki Suzuki

Uterine artery pseudoaneurysm is a rare but important complication of cesarean section (CS). If treated inadequately, it may cause profuse life‐threatening postpartum hemorrhage. We report an asymptomatic postpartum woman with uterine artery pseudoaneurysm after CS. We also provide a review of published reports of pseudoaneurysm after CS. A 31‐year‐old Japanese woman underwent CS, in which the uterine incision was extended laterally. Routine postoperative evaluation with vaginal ultrasound on postpartum day 6 revealed a parauterine mass with a maximum diameter of 49 mm with swirling flow. Selective angiography confirmed this mass as a uterine artery pseudoaneurysm. Uterine artery embolization was performed with success. Uterine artery pseudoaneurysm should be listed as a differential diagnosis of pelvic mass after CS.


Journal of Obstetrics and Gynaecology Research | 2009

Opening the bladder for cesarean hysterectomy for placenta previa percreta with bladder invasion

Shigeki Matsubara; Akihide Ohkuchi; Masahiro Yashi; Akio Izumi; Michitaka Ohwada; Tomoyuki Kuwata; Rie Usui; Yoshimine Kuwata; Manabu Nakata; Mitsuaki Suzuki

Cesarean hysterectomy for placenta previa percreta with bladder invasion often induces not only massive hemorrhage but also severe bladder/ureter injuries. A 37‐year‐old woman with previous cesarean delivery suffered placenta previa percreta with bladder invasion. At the 34th week, we performed cesarean hysterectomy. Without separating the bladder from the uterus/cervix, we incised the bladder lateral wall using an automatic stapling/cutting device, leaving the bladder posterior wall adhering to the uterus and resecting it with the uterus. The bladder was easily repaired without urological sequelae. We suggest a new, simple and safe technique for cesarean hysterectomy for this disease.


Journal of Perinatal Medicine | 2010

A novel method for evaluating uterine cervical consistency using vaginal ultrasound gray-level histogram

Tomoyuki Kuwata; Shigeki Matsubara; Nobuyuki Taniguchi; Akihide Ohkuchi; Takashi Ohkusa; Mitsuaki Suzuki

Abstract Aims: To evaluate uterine cervical consistency using a vaginal ultrasound gray-level histogram. Methods: Vaginal ultrasound and digital examination were performed for 214 women with low-risk singleton pregnancy during 27–30th pregnancy week. The mean gray-level (MGL) of an ultrasound gray-level histogram, representing the echogenicity of a region of interest, was measured in the midsection of anterior and posterior cervical walls. The difference in MGL between anterior and posterior (AP difference) was related to the Bishop sub-score for cervical consistency (0, 1, or 2), determined before ultrasound. Results: A larger positive AP difference indicated significantly lower Bishop sub-score. After analyzing the receiver operator characteristic curves for the AP difference, a value of 1.42 and –1.98 was the best cut-off value to determine a hard cervix (score 0) and a soft cervix (score 2), respectively. To identify a hard cervix, this test had 71% sensitivity and 82% specificity. For a soft cervix, it was 66% and 87%, respectively. Conclusions: A more echogenic anterior than posterior cervix indicates a hard cervix; the greater the difference in echogenicity between anterior and posterior walls the harder the cervix. The difference in MGL of the ultrasound gray-level histogram may enable objective evaluation of cervical consistency.


Gynecologic and Obstetric Investigation | 2008

Decidualization of Ovarian Endometriosis during Pregnancy Mimicking Malignancy : Report of Three Cases with a Literature Review

Shizuo Machida; Shigeki Matsubara; Michitaka Ohwada; Manabu Ogoyama; Tomoyuki Kuwata; Takashi Watanabe; Akio Izumi; Mitsuaki Suzuki

Background: Intracystic papillary excrescence is a characteristic morphological feature of ovarian malignancy. A few recent reports have demonstrated that ovarian endometriotic cysts, undergoing decidualization during pregnancy, occasionally show excrescence, necessitating surgery during pregnancy; however, this phenomenon is not well recognized among clinicians. Cases: Three pregnant women with decidualized ovarian endometriosis showed excrescence. Both ultrasound and magnetic resonance imaging (MRI) preoperatively suggested the presence of underlying ovarian endometriotic cysts in 2 women, but not in the other. Intracystic papillary excrescence prompted us to perform laparotomy at 14, 14, and 19 weeks of pregnancy, respectively, with 1 woman aborting in the 21st week, and with 2 delivering healthy term infants. Histological examination confirmed the diagnosis of decidualized ovarian endometriotic cysts in all 3 patients. Conclusions: We provide the first report of pregnant women in whom excrescence occurred from ovarian endometriotic cysts without preoperative evidence. Decidualized ovarian endometriosis, even without preoperative morphological features of endometriosis, should be added to the differential diagnosis of ovarian malignancy during pregnancy.


Metabolism-clinical and Experimental | 1997

Calcium-to-creatinine ratio in spot urine samples in early pregnancy and its relation to the development of preeclampsia

Akio Izumi; Hisanori Minakami; Tomoyuki Kuwata; Ikuo Sato

We investigated the relation between an alteration in calcium (Ca) excretion in early pregnancy and the risk of preeclampsia in 1,147 pregnant women. We measured Ca and creatinine (Cr) concentrations in spot urine samples obtained at 12 weeks or less of gestation. Seventy-one (6.2%) had hypertension alone, nine (0.8%) developed superimposed preeclampsia, 39 (3.4%) developed proteinuria alone, and 13 (1.1%) developed preeclampsia; 1,015 women did not develop hypertension or proteinuria. The Ca/Cr ratio was significantly reduced in the 39 women who eventually developed proteinuria (0.116 +/- .103) and 13 who developed preeclampsia (0.121 +/- .063) compared with 1,015 women who had neither hypertension nor proteinuria (0.158 +/- .239). The relative risk of development of preeclampsia, proteinuria, or superimposed preeclampsia was 1.98 (95% confidence interval, 1.22 to 3.22) for women with a Ca/Cr ratio less than the 30th percentile (0.082) compared with women with a Ca/Cr ratio greater than the 30th percentile. These results suggest that preeclampsia may be related, in part, to a relative Ca intake deficiency. Determination of the Ca/Cr ratio in spot urine samples in the first trimester is of only limited clinical value for identifying women with an increased risk of preeclampsia.


Journal of Obstetrics and Gynaecology Research | 2014

Anterior placentation as a risk factor for massive hemorrhage during cesarean section in patients with placenta previa.

Yosuke Baba; Shigeki Matsubara; Akihide Ohkuchi; Rie Usui; Tomoyuki Kuwata; Hirotada Suzuki; Hironori Takahashi; Mitsuaki Suzuki

In placenta previa (PP), anterior placentation, compared with posterior placentation, is reported to more frequently cause massive hemorrhage during cesarean section (CS). Whether this is due to the high incidence of placenta accreta, previous CS, or a transplacental approach in anterior placenta is unclear. We attempted to clarify this issue.

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Rie Usui

Jichi Medical University

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Akio Izumi

Jichi Medical University

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Manabu Nakata

Jichi Medical University

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