Synovial plicae and temporomandibular joint disorders: surgical findings.

PURPOSE: Synovial plicae and their relation to pain and disability have been reported in the orthopedic literature in association with the knee and other extremity joints. However, the occurrence of synovial plicae in the temporomandibular joint (TMJ) have rarely been reported. This report describes the surgical appearance, distribution, and histologic findings of synovial plicae in patients with TMJ recurrent dislocation and internal derangement. MATERIALS AND METHODS: Twenty consecutive patients, 16 with recurrent dislocation and 4 with internal derangement, who underwent open TMJ surgery by the same surgeon from 2010 to 2013 were studied retrospectively. RESULTS: Synovial plicae were detected in 18 of 28 joints (64.3%). Synovial plicae were observed in 15 of 24 joints (62.5%) with recurrent dislocation and in 3 of 4 joints (75%) with internal derangement. Histologic findings of these plicae were consistent with dense fibrous or cartilaginous tissues, with some exhibiting a synovial lining. CONCLUSIONS: Although the role of synovial plicae in TMJ disorders is unknown and unstudied, consideration should be given to investigating the possible relation of these structures to the signs and symptoms of TMJ disorders.

Adverse pregnancy outcomes associated with adenomyosis with uterine enlargement.

AIM: The aim of this study was to elucidate the risk of poor pregnancy outcomes in women with adenomyosis by comparing their outcomes to those of women without uterine abnormalities. MATERIAL AND METHODS: The subjects were 36 women diagnosed with adenomyosis before pregnancy who were managed at a tertiary care center between January 2002 and December 2012. Our hospital database was retrospectively reviewed to identify pregnancy outcomes associated with adenomyosis. The control group consisted of 144 women without uterine abnormalities who gave birth during the same period and whose age at delivery was adjusted by applying propensity scores. Pregnancy outcomes were compared between the adenomyosis and control groups. The main outcomes were gestational age at delivery, preterm delivery, preterm premature rupture of membranes, fetal malpresentation, cesarean delivery, small-for-gestational age, 5-min Apgar score < 7, umbilical arterial pH < 7.1, and neonatal intensive care unit admission. The data are presented as medians (range) or frequencies (percentage). RESULTS: The adenomyosis group had significantly higher rates of preterm delivery (41.7% vs 12.5%), preterm premature rupture of membranes (19.4% vs 4.2%), small-for-gestational age (33.3% vs 10.4%), fetal malpresentation (27.8% vs 8.3%), and cesarean delivery (58.3% vs 24.3%), as compared with the control group. No significant differences were observed in 5-min Apgar score < 7 or umbilical arterial pH < 7.1 between the two groups. CONCLUSIONS: Pregnancies in women with adenomyosis were associated with a higher preterm delivery rate and more frequent occurrences of fetal growth restriction and fetal malpresentation, such that both pregnancy and delivery outcomes were poor.

Prediction of perinatal outcomes based on primary symptoms in women with placental abruption.

AIMS: Placental abruption is an important cause of perinatal mortality and morbidity. Although there are many reports on the risk factors for placental abruption, there are few on its classification. Our aim is to evaluate the associations between primary symptoms and the outcomes of placental abruption. MATERIAL AND METHODS: We carried out a retrospective cohort study of 12,474 births at the Perinatal Center for Maternity and Neonates of the Yokohama City University Medical Center between January 2000 and December 2012. There were 151 women with placental abruption, 136 of whom were included in this study. The subjects were classified into two groups according to their primary symptoms: those with bleeding (external bleeding group) and those with abdominal pain (abdominal pain group). Maternal and neonatal outcomes were compared between the two groups. RESULTS: Both fetal and maternal outcomes were significantly poorer in the abdominal pain group than in the external bleeding group in terms of intrauterine fetal death (6.5% vs 33.3%, P < 0.001), perinatal mortality (8.1% vs 33.3%, P = 0.001), umbilical arterial pH < 7.1 (15.7% vs 57.1%, P < 0.001), bleeding volume, rate of blood transfusion, and disseminated intravascular coagulation incidence. CONCLUSIONS: This classification based on primary symptoms was found to be useful for predicting both maternal and neonatal outcomes of placental abruption.

Clinical features of gestational thrombocytopenia difficult to differentiate from immune thrombocytopenia diagnosed during pregnancy.

AIM: To investigate the clinical features of gestational thrombocytopenia (GT) difficult to differentiate from immune thrombocytopenia (ITP) during pregnancy. METHODS: The January 2000-December 2012 hospital database was analyzed to identify women with ITP or GT (after excluding other possible causes of thrombocytopenia) among those first noted to have platelet counts of less than 100 000/µL during pregnancy. The maternal characteristics, platelet count fluctuations and pregnancy outcomes were compared between women with ITP and GT. RESULTS: There were 23 pregnancies (22 women) with thrombocytopenia (GT, 13; ITP, 10). The GT group included five twin pregnancies (38.5%), whereas all pregnancies of the ITP group were singleton pregnancies, with significantly more twin pregnancies in the GT group (P = 0.046). Thrombocytopenia in the first trimester occurred in 70% (7/10) of ITP cases and 23.1% (3/13) of even GT cases. The nadir platelet count was less than 70 000/µL in 100% (10/10) of ITP cases and 30.8% (4/13) of GT cases (P < 0.001). Maternal treatment was required in 80% (8/10) of ITP cases, but in none of the GT cases. The pregnancy outcomes were favorable in both groups, and no case required fetal treatment. CONCLUSION: Gestational thrombocytopenia with platelet counts of less than 10 0000/µL occurred more frequently in twin pregnancies. Although onset of thrombocytopenia in the first trimester and a platelet count of less than 70 000/µL is more common in ITP, these findings were not uncommon in GT. Differentiation between ITP and GT may be feasible only with post-partum changes in the platelet count.

Pregnancy outcomes of women with coexisting systemic lupus erythematosus flare and preeclampsia.

OBJECTIVES: Systemic lupus erythematosus (SLE) flare and preeclampsia are difficult to differentiate from each other and occasionally coexist; This study aimed to analyze cases requiring termination of pregnancy due to SLE flare or preeclampsia and to elucidate the association between these two conditions; Methods. Out of 71 pregnancies in 60 women managed for SLE-complicated pregnancies who delivered at or after 22 weeks' gestation at a tertiary center, 7 pregnancies were terminated due to uncontrollable severe SLE flare or severe preeclampsia We retrospectively analyzed the clinical courses and laboratory findings of these 7 cases to determine whether their pathological conditions were attributable to SLE flare alone, preeclampsia alone, or the coexistence of these two conditions. RESULTS: One of the 7 cases had preeclampsia alone, two had SLE alone, and four had both conditions. The coexistence of preeclampsia and SLE was thus the most common condition. In cases with both conditions, SLE flare had preceded preeclampsia, thereby making treatment after delivery difficult. CONCLUSION: Severe SLE flare often preceded severe preeclampsia and worsened after delivery. When differentiating severe SLE flare from severe preeclampsia is difficult during pregnancy, women should be regarded as having SLE flare rather than preeclampsia and aggressively treated.

A classification of congenital uterine anomalies predicting pregnancy outcomes.

OBJECTIVE: To evaluate pregnancy outcomes in women with uterine anomalies by applying a method for diagnosing and classifying congenital uterine malformations. DESIGN: Retrospective study. SETTING: Tertiary care center. POPULATION: Ninety-four women with uterine anomalies who delivered after 22 gestational weeks. METHODS: Excluding the 14 women with a history of surgery and seven with one endometrial cavity, 73 women with two endometrial cavities were subdivided into those with two external uterine orifices (2-OS subgroup) and those with one external uterine orifice (1-OS subgroup). MAIN OUTCOME MEASURES: Pregnancy outcomes, such as preterm birth, abnormal fetal presentation, cesarean delivery and placental abruption. RESULTS: The 2-OS subgroup comprised women with a didelphic or complete septate uterus who had a significantly higher rate of cesarean delivery (91% vs. 18%, p < 0.001) than the control group (normal uterine morphology; n = 5763). The 1-OS subgroup comprised women with a bicornuate or incomplete septate uterus who had significantly higher rates of preterm birth (27% vs. 5%, p < 0.001) and placental abruption (14% vs. 0.7%, p < 0.001) than the control group. CONCLUSIONS: Classification of uterine anomalies by the number of uterine endometrial cavities and external uterine orifices is an easy and reliable means of predicting pregnancy outcomes.

Associations of maternal pre-pregnancy underweight with small-for-gestational-age and spontaneous preterm birth, and optimal gestational weight gain in Japanese women.

AIM: To determine associations of maternal pre-pregnancy underweight with poor outcomes and evaluate how gestational weight gain affects risks for such outcomes in pre-pregnancy underweight Japanese women. METHODS: By analyzing the January 2001-December 2012 hospital database, we retrospectively identified 6954 women with pre-pregnancy normal weights (body mass index, 18.5-24.9 kg/m²) and 1057 pre-pregnancy underweight women (body mass index, <18.5 kg/m²) who delivered at the Perinatal Maternity and Neonatal Center of Yokohama City University. These women were stratified by weekly weight gain during the second/third trimesters to investigate associations of gestational weight gain with spontaneous preterm birth and small for gestational age (SGA). Spontaneous preterm birth and SGA incidences were compared with those of women meeting Institute of Medicine (IO M) guidelines to determine optimal weight gain in Japanese women. RESULTS: Preterm birth and SGA incidences were significantly higher in pre-pregnancy underweight than in pre-pregnancy normal weight women (4.6% vs 2.4% [P=0.005] and 13.9% vs 9.7% [P = 0.003], respectively). For pre-pregnancy normal weight women, preterm birth incidence was significantly higher in those with weight gain of less than 0.2 kg/week than in those IOM guidelines. For pre-pregnancy underweight women, preterm birth and SGA incidences were significantly higher in those with weight gain of less than 0.3 kg/week than in those meeting IOM guidelines. CONCLUSION: Preterm birth and SGA incidences did not differ significantly between pre-pregnancy normal weight women with weight gain of 0.2 kg/week or more and pre-pregnancy underweight women with weight gain of 0.3 kg/week or more, as compared to women meeting IOM guidelines. These results suggest that IOM guidelines for gestational weight gain may lack external validity in Japanese women.

Emergency cerclage versus expectant management for prolapsed fetal membranes: a retrospective, comparative study.

AIM: To compare outcomes after emergency cerclage versus expectant management for prolapsed fetal membranes in women with cervical incompetency. METHODS: The January 2000-December 2012 hospital database was analyzed to identify women managed for prolapsed fetal membranes who did not have premature rupture of membranes, clinically discernible chorioamnionitis, or treatment-resistant uterine contractions from 15 to 26 weeks of gestation retrospectively. Durations of pregnancy prolongation and numbers of deliveries after 32 and 28 weeks were compared between women undergoing emergency cervical cerclage and those receiving expectant management. RESULTS: Fifteen of the 35 women underwent emergency cervical cerclage ('cerclage group'), while the other 20 were managed expectantly ('bedrest group'). In the cerclage group, median gestational ages at procedure and delivery times were 22.6 (15.9-26.1) and 32.4 (19.4-41.6) weeks, respectively. Median gestational ages on admission and at delivery in the bedrest group were 23.4 (21.1-26.4) and 26.0 (23.1-36.4) weeks, respectively. The median duration of pregnancy prolongation was 44 days (4-165) in the cerclage group and 12.5 days (2-93) in the bedrest group (P < 0.01). Numbers of deliveries after 28 and 32 weeks were both significantly higher in the cerclage than in the bedrest group (P < 0.05). CONCLUSION: In women with prolapsed fetal membranes but no signs of infection or painful uterine contractions, emergency cervical cerclage prolonged pregnancy duration as compared with expectant management.

Significance of cervical ripening in pre-induction treatment for premature rupture of membranes at term.

AIM: This study aimed to determine whether mechanical cervical dilatation with a laminaria tent in women with premature rupture of membranes (PROM) at term may influence the maternal/neonatal outcomes. METHODS: We reviewed the medical records and histopathologic results of the placenta in 782 women with PROM at term. Of the 486 women seen prior to 2010 (group 1), 85 had Bishop scores of 5 or less and underwent insertion of laminaria tents (group A). In the 296 women admitted after 2010 (group 2), 27 had Bishop scores of 5 or less and underwent labor management without insertion of laminaria tents (group B). The patient characteristics, delivery course and neonatal outcomes were compared between the groups. RESULTS: There were no significant differences in the maternal age, percentage of nulliparas, body mass index, gestational age at delivery or Bishop score between the groups. The Bishop score improved from 2.5 to 6.1 after laminaria tent insertion in group A. However, there were no significant intergroup differences in the frequency of use of labor-inducing agents or the time interval from PROM to delivery. The incidence of clinical/pathological chorioamnionitis was not higher in group A than in group B. No significant differences were found in the Apgar scores, umbilical artery pH or frequency of asphyxia neonatorum between the groups. Mechanical cervical dilatation by laminaria tent insertion neither increased the incidence of infection nor contributed to improvement of the perinatal prognosis. CONCLUSION: Mechanical cervical dilatation does not provide any benefit for women with PROM at term.

Guidelines for obstetrical practice in Japan: Japan Society of Obstetrics and Gynecology (JSOG) and Japan Association of Obstetricians and Gynecologists (JAOG) 2014 edition.

The 'Clinical Guidelines for Obstetrical Practice, 2011 edition' were revised and published as a 2014 edition (in Japanese) in April 2014 by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists. The aims of this publication include the determination of current standard care practices for pregnant women in Japan, the widespread use of standard care practices, the enhancement of safety in obstetrical practice, the reduction of burdens associated with medico-legal and medico-economical problems, and a better understanding between pregnant women and maternity-service providers. The number of Clinical Questions and Answers items increased from 87 in the 2011 edition to 104 in the 2014 edition. The Japanese 2014 version included a Discussion, a List of References, and some Tables and Figures following the Answers to the 104 Clinical Questions; these additional sections covered common problems and questions encountered in obstetrical practice, helping Japanese readers to achieve a comprehensive understanding. Each answer with a recommendation level of A, B or C was prepared based principally on 'evidence' or a consensus among Japanese obstetricians in situations where 'evidence' was weak or lacking. Answers with a recommendation level of A or B represent current standard care practices in Japan. All 104 Clinical Questions and Answers items, with the omission of the Discussion, List of References, and Tables and Figures, are presented herein to promote a better understanding among English readers of the current standard care practices for pregnant women in Japan.

Retrospective study of pregnant women placed under expectant management for persistent hemorrhage.

OBJECTIVE: To examine the clinicopathological characteristics of pregnant women who presented with intermittent hemorrhage occurring throughout pregnancy until delivery. METHOD: A total of 24 women with intermittent hemorrhage occurring throughout pregnancy were categorized into two groups, a group with persistent subchorionic hematoma (PSH) and another with chronic abruption (CA), and the pregnancy outcomes were compared between the two groups. The data were expressed as medians (range). RESULTS: There were 18 women in the PSH group and 6 women in the CA group. The median gestational age at delivery was 27.9 (22.1-33.4) weeks in the PSH group and 32.9 (24.3-33.1) weeks in the CA group, revealing a significantly earlier gestational age at delivery in the former group (p = 0.014). The percentage of the women developing acute abruption tended to be higher in the CA group [66.7 % (4/6)] than in the PSH group [26.3 % (5/18)]. Small for gestational age (SGA) infants and neonatal chronic lung disease were seen at high incidences, but only in the PSH group [21.1 % (4/18) and 42.1 % (8/18), respectively]. CONCLUSION: PSH was associated with earlier gestational age at delivery, a higher incidence of SGA infants, and poorer pregnancy outcomes than CA.

Generation of mouse models for type 1 diabetes by selective depletion of pancreatic beta cells using toxin receptor-mediated cell knockout.

By using the toxin receptor-mediated cell knockout (TRECK) method, we have generated two transgenic (Tg) murine lines that model type 1 (insulin-dependent) diabetes. The first strain, C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg, carries the diphtheria toxin receptor (hDTR) driven by the human insulin gene promoter, while the other strain, C57BL/6-ins2(BAC)-TRECK-Tg, expresses hDTR cDNA under the control of the mouse insulin II gene promoter. With regard to the C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg strain, only one of three Tg strains exhibited proper expression of hDTR in pancreatic ß cells. By contrast, hDTR was expressed in the pancreatic ß cells of all four of the generated C57BL/6-ins2(BAC)-TRECK-Tg strains. Hyperglycemia, severe ablation of pancreatic ß cells and depletion of serum insulin were observed within 3days after the administration of diphtheria toxin (DT) in these Tg mice. Subcutaneous injection of a suitable dosage of insulin was sufficient for recovery from hyperglycemia in all of the examined strains. Using the C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg model, we tried to perform regenerative therapeutic approaches: allogeneic transplantation of pancreatic islet cells from C57BL/6 and xenogeneic transplantation of CD34(+) human umbilical cord blood cells. Both approaches successfully rescued C.B-17/Icr-Prkdc(scid)/Prkdc(scid)-INS-TRECK-Tg mice from hyperglycemia caused by DT administration. The high specificity with which DT causes depletion in pancreatic ß cells of these Tg mice is highly useful for diabetogenic research.

Expression of angiotensin II receptor-like 1 in the placentas of pregnancy-induced hypertension.

Angiotensin II receptor-like 1 (APJ), a G protein-coupled receptor that was identified as a homologue of angiotensin II type 1 (AT1) receptor, exerts antagonistic effects on AT1-mediated vasoconstriction. Studies on pregnancy-induced hypertension (PIH) revealed aberrant activation of AT1 downstream signaling. In contrast, little is known about APJ in the pathophysiology of human pregnancy. In this study, we investigated APJ expression in normal human and PIH placentas. mRNAs were extracted from 50 placental villous tissues of 18 cases with severe PIH (8 late-onset, 4 early-onset, and 6 superimposed PIH) and 32 control pregnancies (including 6 preterm cases). Histopathologic studies were conducted using paraffin-embedded placental tissues from 12 control placentas (from 23 to 39 wk) and 23 PIH placentas (from 24 to 41 wk). Reverse transcriptase-polymerase chain reaction showed that APJ was cooperatively expressed with its ligand apelin and AT1 in controls and in late-onset PIH placentas but was significantly downregulated in early-onset PIH placentas with poor fetal growth. Quantitative reverse transcriptase-polymerase chain reaction analysis revealed upregulated APJ in late-onset PIH placentas but significantly downregulated APJ in early-onset PIH. In immunohistochemical staining, APJ was detected strongly in villous capillary endothelial cells and trophoblasts of late-onset PIH placentas. In contrast, APJ was poorly stained in endothelial cells of hypoplastic villi of early-onset PIH placentas. Collective data indicate that the apelin-APJ system is involved in fetoplacental circulation during human pregnancy. Impaired APJ expression in early-onset PIH placentas may reflect an aggravated placental condition with poor fetal growth.

Quality-assessments of characteristics of placental/umbilical cord blood associated with maternal age- and parity-related factor.

Umbilical cord blood (CB) has been widely used for unrelated allogeneic stem cell transplantation. It is important to determine the quality of CB units to avoid frequent problem of limited cell yields. However, no practical and/or optimum obstetric factors to predict them are yet available. This study analyzed the relationship between maternal/neonatal obstetric factors and the laboratory parameters of CB units to identify the optimum factors associated with a high yield of total nucleated cells (TNC). Primiparae in their early 30s may be one of the first selection criteria for CB donors to obtain higher yield of TNC.

Isolation and characterization of mesenchymal stem cells from human umbilical cord blood: reevaluation of critical factors for successful isolation and high ability to proliferate and differentiate to chondrocytes as compared to mesenchymal stem cells from bone marrow and adipose tissue.

Human umbilical cord blood (CB) is a potential source for mesenchymal stem cells (MSC) capable of forming specific tissues, for example, bone, cartilage, or muscle. However, difficulty isolating MSC from CB (CB-MSC) has impeded their clinical application. Using more than 450 CB units donated to two public CB banks, we found that successful cell recovery fits a hyper-exponential function of time since birth with very high fidelity. Additionally, significant improvement in the isolation of CB-MSC was achieved by selecting cord blood units having a volume ≥90 ml and time ≤2 h after donor's birth. This resulted in 90% success in isolation of CB-MSC by density gradient purification and without a requirement for immunoaffinity methods as previously reported. Using MSC isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC) as reference controls, we observed that CB-MSC exhibited a higher proliferation rate and expanded to the order of the 1 × 10(9) cells required for cell therapies. CB-MSC showed karyotype stability after prolonged expansion. Functionally, CB-MSC could be more readily induced to differentiate into chondrocytes than could BM-MSC and AT-MSC. CB-MSC showed immunosuppressive activity equal to that of BM-MSC and AT-MSC. Collectively, our data indicate that viable CB-MSC could be obtained consistently and that CB should be reconsidered as a practical source of MSC for cell therapy and regenerative medicine using the well established CB banking system.

The current status of umbilical cord blood collection in Japanese medical centers: survey of obstetricians.

As the first step of UCB banking, UCB collection has an important role in banking procedures. The aim of this study was to reveal the current status of UCB collection and discuss the management of the UCB bank. We conducted a questionnaire survey at medical centers collecting UCB, followed by semi-structured interviews with some respondents. Out of 38 institutes, 11 respondents (28.9%) thought that collection of UCB in addition to their routine medical services puts a burden on physicians. The obstetricians involved in the UCB collection are generally willing to participate in the procedure under current circumstances at medical institutes.

Guidelines for obstetrical practice in Japan: Japan Society of Obstetrics and Gynecology (JSOG) and Japan Association of Obstetricians and Gynecologists (JAOG) 2011 edition.

Clinical guidelines for obstetrical practice were first published by the Japan Society of Obstetrics and Gynecology (JSOG) and the Japan Association of Obstetricians and Gynecologists (JAOG) in 2008, and a revised version was published in 2011. The aims of this publication include the determination of current standard care practices for pregnant women in Japan, the widespread use of standard care practices, the enhancement of safety in obstetrical practice, the reduction in burdens associated with medico-legal and medico-economical problems, and a better understanding between pregnant women and maternity-service providers. These guidelines include a total of 87 Clinical Questions followed by several Answers (CQ&A), a Discussion, a List of References, and some Tables and Figures covering common problems and questions encountered in obstetrical practice. Each answer with a recommendation level of A, B or C has been prepared based principally on 'evidence' or a consensus among Japanese obstetricians in situations where 'evidence' is weak or lacking. Answers with a recommendation level of A or B represent current standard care practices in Japan. All 87 CQ&A are presented herein to promote a better understanding of the current standard care practices for pregnant women in Japan.

Double superior vena cava and anomaly of cardiovascular system with a review of the literature.

In a student course of gross anatomy dissection at Kanagawa Dental College in 2008, we found an extremely rare case of the double superior vena cava that has a shunt between the right and left atria of a 81-year-old Japanese male cadaver. The left superior vena cava passed through the space between the left cardiac auricle and the left pulmonary vein and entered the coronary sulcus. Then it opened near the opening of the inferior vena cava as the coronary venous sinus to the right atrium. The upper edge of the interatrial septum was located at the site where the right superior vena cava opened to the right atrium. Accordingly, the right atrium connected with left atrium through this site. We discuss the anatomy and etiology of these anomalous structures with a brief review of the literature.

Anomalous bifurcation and island formation of the carotid artery.

An anomalous artery directly connecting the common carotid artery and internal carotid artery was discovered on the right side in the cadaver of an 83-year-old Japanese female, and the facial artery, maxillary artery, and superficial temporal artery arose from the common carotid artery by a common trunk. The anomalous artery arose from the posterior aspect of the common carotid artery at the level of the origin of the superior thyroid artery, and joined the posterior aspect of the internal carotid artery. The anomalous artery was covered by the connective tissue surrounding the common carotid artery and the internal carotid artery. The anomalous anastomosis, especially the proximal portion, may have arisen from the second branchial arch artery during development.

Concise review: isolation and characterization of cells from human term placenta: outcome of the first international Workshop on Placenta Derived Stem Cells.

Placental tissue draws great interest as a source of cells for regenerative medicine because of the phenotypic plasticity of many of the cell types isolated from this tissue. Furthermore, placenta, which is involved in maintaining fetal tolerance, contains cells that display immunomodulatory properties. These two features could prove useful for future cell therapy-based clinical applications. Placental tissue is readily available and easily procured without invasive procedures, and its use does not elicit ethical debate. Numerous reports describing stem cells from different parts of the placenta, using nearly as numerous isolation and characterization procedures, have been published. Considering the complexity of the placenta, an urgent need exists to define, as clearly as possible, the region of origin and methods of isolation of cells derived from this tissue. On March 23-24, 2007, the first international Workshop on Placenta Derived Stem Cells was held in Brescia, Italy. Most of the research published in this area focuses on mesenchymal stromal cells isolated from various parts of the placenta or epithelial cells isolated from amniotic membrane. The aim of this review is to summarize and provide the state of the art of research in this field, addressing aspects such as cell isolation protocols and characteristics of these cells, as well as providing preliminary indications of the possibilities for use of these cells in future clinical applications.