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An abstract of the article "The accuracy of diagnosing placenta previa on transvaginal ultrasound at 20-24 weeks' gestation by distinguishing between the uterine isthmus and cervix," by J. Hasegawa and colleagues is presented.

Background: Noninvasive prenatal testing (NIPT) is used to screen for fetal chromosomal abnormalities, such as fetal aneuploidy, and has been offered at our hospital since 2013. We analyzed data from our center to determine if NIPT screenees could be given more-accurate information on NIPT outcomes., Methods: This retrospective observational study included 819 pregnant women who requested NIPT at Nippon Medical School Hospital from November 2013 to October 2021. We examined medical records for data on NIPT results and clinical outcomes., Results: Of the 819 women, 764 (93.2%) underwent NIPT, and 55 (6.7%) did not. Of the 764 women who underwent NIPT, 17 received a positive result (2.2%), of whom 2 (11.8%), 4 (23.5%), and 11 (64.7%) received a positive result for trisomy 13, 18, and 21, respectively. The true-positive rates after definitive diagnoses of trisomy 13, 18, and 21 were 1 (50%), 3 (75%), and 11 (100%), respectively. Of the 17 positive results, there were two false-positive results (11.8%) (for trisomy 13 and trisomy 18). Eleven women with fetal aneuploidy terminated their pregnancies, and four cases resulted in intrauterine fetal death. Five neonates with negative NIPT results had congenital disease without chromosomal abnormality. Two patients had indeterminate results from the first blood sampling, possibly because of treatment with unfractionated heparin. The results of repeat testing after heparin cessation were negative., Conclusions: Our results were generally similar to nationwide data for Japan. NIPT providers can provide more detailed and individualized genetic counseling for each situation by understanding their own medical facility's data in detail.

Background: Miscarriage occurs in 10-15% of pregnancies and recurrent pregnancy loss (RPL) occurs in 1% of couples hoping for a child. Various risk factors, such as thrombophilia, uterine malformation, and embryonic chromosomal aberration cause RPL. We hypothesized that antithrombotic therapy for RPL patients with thrombophilia would reduce miscarriage due to thrombophilia, which would reduce the total miscarriages and result in a relative increase in miscarriage due to embryonic chromosomal aberrations. In this study, we investigated the incidence of chromosomal aberrations in products of conception in RPL patients with and without antithrombotic therapy., Methods: We performed a single-center, retrospective review of cases diagnosed as miscarriage with embryo chromosome analysis between July 1, 2000, and May 31, 2019. Rates of chromosomal aberration were compared between RPL patients with and without thrombophilia or antithrombotic therapy., Results: One hundred and-ninety RPL cases were analyzed. The average age was 37.4 ± 4.3 years, and the average number of previous pregnancy losses was 2.2 ± 1.1. The overall chromosomal aberration rate was 67.4% (128/190). There was no difference in the chromosomal aberration rate between the factors for RPL, with or without thrombophilia, and antithrombotic therapy. Only advancing maternal age had significant correlation to increased embryo chromosomal aberration rates., Conclusions: With or without antithrombotic therapy, miscarriage was caused by embryonic chromosome abnormalities at a certain rate. Antithrombotic therapy in RPL patients with thrombophilia may reduce abortions due to thrombophilia, which may also normalize the rate of embryonic chromosome aberrations in the subsequent miscarriages.

Improvements in cancer therapy have enabled further insight into the long-term effects of treatment, including the highly prevalent gonadal failure. The focus of treatment has been shifted to the preservation of fertility, which may be achieved by preventing ovarian toxicity. To this end, new molecular-targeted agents, including monoclonal antibodies, have been developed and used in a standard procedure for managing different cancers. However, the prolonged antitumor activity of these drugs may cause the emergence of new toxic effects. The aim of the present review was to discuss the leading toxic effect of the anti-angiogenic agent bevacizumab on ovarian function in female patients of reproductive age, which may be observed and expected during in clinical practice. The majority of bevacizumab-induced side effects are expected to be transient and eliminated within the anticipated drug clearance time frame; however, fundamental investigations on these effects are required for generating more evidence-based practice guidelines.

Objective: The preterm birth rate of twins is reportedly higher than that of single pregnancies. We performed preliminary preventive interventions at our center focused on evaluating the risk of each case before 14 weeks of gestation to reduce the spontaneous preterm birth rate., Materials and Methods: The participants included 184 dichorionic-diamniotic twins delivered at our center during the 8 years from 2006. We evaluated each patient regarding high-risk status (at least 1 additional factor as follows: threatened abortion, history of chorioamnionitis, cervicitis, and bacterial vaginosis), based on available evidence; patients deemed high risk gave their informed consent and underwent treatment for cervicitis and cerclage if indicated. We divided the patients into two groups depending on whether the management was initiated before (Group A) or after (Group B) 14 weeks. We further divided Group A into three: Group 1 underwent treatment for cervicitis, Group 2 underwent cervical cerclage in addition to treatment for cervicitis, and Group 3 did not undergo preventive treatment. We retrospectively compared the preterm birth rates of the two groups, and we also compared them between the higher-risk group (Group 1 + 2) and the no additional risk group (Group 3) in Group A., Results: The spontaneous preterm birth rate < 36 weeks was significantly lower in Group A (4/90; 4.4%) than in Group B (18/94; 19.1%) (p=0.001). However, there were no significant differences between Group 1 + 2 and Group 3 (2/42 vs. 2/46). Focusing on the spontaneous preterm birth rate < 34 weeks, Group A had a lower rate than Group B (2/90; 2.2% vs. 13/94; 13.8%, p=0.0012)., Conclusion: Even though this was a preliminary study, the results are promising, and we propose custom-made management for dichorionic-diamniotic twins: (1) earlier management from before 14 weeks; (2) high-risk selection for cervicitis and a short cervix; and (3) intervention with anti-inflammatory agents and cerclage if indicated., (Copyright © 2017 Taiwan Association of Obstetrics & Gynecology. Published by Elsevier B.V. All rights reserved.)

Purpose: To evaluate whether type and location of placenta previa affect risk of antepartum hemorrhage-related preterm delivery., Methods: We retrospectively studied 162 women with singleton pregnancies presenting placenta previa. Through observation using transvaginal ultrasound the women were categorized into complete or incomplete placenta previa, and then assigned to anterior and posterior groups. Complete placenta previa was defined as a placenta that completely covered the internal cervical os, with the placental margin >2 cm from the os. Incomplete placenta previa comprised marginal placenta previa whose margin adjacent to the internal os and partial placenta previa which covered the os but the margin situated within 2 cm of the os. Maternal characteristics and perinatal outcomes in complete and incomplete placenta previa were compared, and the differences between the anterior and the posterior groups were evaluated., Results: Antepartum hemorrhage was more prevalent in women with complete placenta previa than in those with incomplete placenta previa (59.1% versus 17.6%), resulting in the higher incidence of preterm delivery in women with complete than in those with incomplete placenta previa [45.1% versus 8.8%; odds ratio (OR) 8.51; 95% confidence interval (CI) 3.59-20.18; p < 0.001]. In complete placenta previa, incidence of antepartum hemorrhage did not significantly differ between the anterior and the posterior groups. However, gestational age at bleeding onset was lower in the anterior group than in the posterior group, and the incidence of preterm delivery was higher in the anterior group than in the posterior group (76.2% versus 32.0%; OR 6.8; 95% CI 2.12-21.84; p = 0.002). In incomplete placenta previa, gestational age at delivery did not significantly differ between the anterior and posterior groups., Conclusion: Obstetricians should be aware of the increased risk of preterm delivery related to antepartum hemorrhage in women with complete placenta previa, particularly when the placenta is located on the anterior wall.

Cesarean scar pregnancy is one of the rare types of ectopic pregnancy. Ultrasonography enables early diagnosis and the successful preservation of the uterus. However, the correct diagnosis of cesarean scar pregnancy can be difficult in some cases. We describe a case of cesarean scar pregnancy that was initially misdiagnosed on the basis of current ultrasonographic criteria. Ultrasonographic images at 9 weeks' gestation demonstrated no gestational sac but did show a bulging mass in uterine wall with irregularly shaped hypoechoic areas, which resembled the lacunae in placenta previa. Color Doppler imaging demonstrated that the lacunae-like areas were richly perfused. Cesarean scar pregnancy was finally diagnosed with magnetic resonance imaging, which showed a lack of myometrium in the lower anterior uterine wall with placental invasion. Histological examination of the uterus after hysterectomy revealed the direct invasion of trophoblasts into the mural zone which had resulted in a deficit of myometrium at the previous cesarean scar. A mass in the myometrium with richly perfused lacunae-like areas should be considered as one of the important ultrasonographic findings indicating cesarean scar pregnancy.

The aim of our study was to use brachial-ankle pulse wave velocity (baPWV) measurements to noninvasively assess the effect of exercise training on arterial stiffness in normal pregnant women. Arterial stiffness was assessed at the beginning of the early second trimester of pregnancy and 1 month after delivery in 17 women with normal singleton pregnancies who exercised regularly throughout pregnancy: 81 matched controls were used for comparison. No significant differences were observed in baPWV between the exercise and control groups at the beginning of the second trimester. BaPWV 1 month after delivery (1160.2 ± 109.1 cm·second(-1)) was signifi-cantly higher than that in the early second trimester (1116.7 ± 87.9 cm·second(-1)) in the control group (indicating increased arterial stiffness), but not in the exercise group (1145.9 ± 88.1 cm/second vs 1122.7 ± 100.2 cm·second(-1), respectively: not significant). The results indicated that regular maternal exercise training decreased arterial stiffness in normal pregnant women, which suggests that regular exercise may help prevent hypertensive disorders during pregnancy. Key pointsRegular maternal exercise training decreased arterial stiffness in normal pregnant women, which suggests that regular exercise may help prevent hypertensive disorders during pregnancy.Maternal exercise suggests that disturbances in arterial function during pregnancy may be prevented by regular exercise.

Synaptic remodelling coordinated with dendritic growth is essential for proper development of neural connections. After establishment of synaptic contacts, synaptic junctions are thought to become stationary and provide fixed anchoring points for further dendritic growth. However, the possibility of active translocation of synapses along dendritic protrusions, to guide the proper arrangement of synaptic distribution, has not yet been fully investigated. Here we show that immature dendrites of γ-aminobutyric acid-positive interneurons form long protrusions and that these protrusions serve as conduits for retrograde translocation of synaptic contacts to the parental dendrites. This translocation process is dependent on microtubules and the activity of LIS1, an essential regulator of dynein-mediated motility. Suppression of this retrograde translocation results in disorganized synaptic patterns on interneuron dendrites. Taken together, these findings suggest the existence of an active microtubule-dependent mechanism for synaptic translocation that helps in the establishment of proper synaptic distribution on dendrites.

Objective: The objective of this study was to explore factors influencing the accuracy of transvaginal digital examination for determining fetal head position during the first stage of labor., Materials and Methods: Fetal head position was assessed in 87 women in the first stage of labor at term with normal singleton cephalic presentation. Transvaginal digital examinations were performed by attending midwives and were followed immediately by transabdominal ultrasound assessments performed by a single sonographer. Accuracy was defined as agreement of the results of each examination. Multivariate logistic regression analysis was performed to determine the independent factors influencing accuracy., Results: In only 40.3% of patients (n = 35) were transvaginal digital examinations consistent with ultrasound assessments. Multivariate logistic regression analysis showed that the accuracy of digital examinations was significantly associated with cervical dilatation more than 7 cm (odds ratio, 3.01; 95% confidence interval [CI], 1.03-9.4), birth weight less than 2,500 g (odds ratio, 8.68; 95% CI, 1.08-86.28), and the anterior occiput position group (odds ratio, 4.73; 95% CI, 1.76-13.49)., Conclusions: The present study demonstrates that transvaginal digital examination is less accurate than ultrasonography for determining fetal head position during the first stage of labor. The results suggest that ultrasound assessments should be routinely performed in patients with a cervical dilatation less than 7 cm, an estimated fetal body weight more than 2,500 g, the occiput posterior position, or the occiput transverse position.

Background: The incidence of placenta previa has been increasing. It is of a great importance to determine the clinical risk factors for peripartum blood transfusion in women with placenta previa in an effort to anticipate cases of severe hemorrhage., Methods: A total of 129 consecutive cases of placenta previa (64 cases of complete placenta previa and 65 cases of marginal placenta previa), including 43 cases requiring blood transfusion, were retrospectively analyzed. Maternal and neonatal clinical data were examined with univariate and multivariate logistic regression analyses for potential risk factors for peripartum blood transfusion., Results: The independent risk factors for blood transfusion were maternal age greater than 34 years (adjusted odds ratio [OR]=3.7; 95% confidence interval [CI]=1.5-7.5, p<0.05), history of having undergone dilatation and curettage more than once (adjusted OR=4.8; 95% CI=1.1-26.2, p<0.05), and complete placenta previa (adjusted OR=2.6, 95% CI=1.2-5.9, p<0.05). Body mass index, gravidity, parity, previous cesarean section, antepartum hemorrhage, use of tocolytic agents, gestational age at delivery, preoperative anemia, emergent surgery, birth weight, and Apgar score were not associated with the incidence of blood transfusion., Conclusion: Risk factors for blood transfusion in women with placenta previa are advanced maternal age, repeat dilatation and curettage, and complete placenta previa. Women with placenta previa who are at risk for blood transfusion should be carefully managed with sufficient preparation for blood transfusion.

Objective: The aims of this study were to assess the frequency of inpatient falls and to evaluate potential risk factors in an academic hospital., Methods: An electronic audit of the inpatient database at the Tama-Nagayama Hospital of Nippon Medical School from April 2004 through March 2005 was performed. Inpatient falls were registered regularly with incident reports submitted by nurses and other hospital employees discovering the fall. All inpatients were analyzed for potential risk factors using univariate and multivariate logistic regression analysis., Results: Of the 8,537 patients, 109 (1.3%) fell. Multivariate logistic regression analysis showed that inpatient falls were significantly associated with a patient age of 51 to 70 years (odds ratio, 2.4; 95% CI, 1.3 - 4.7) or of 71 to 90 years (odds ratio, 4.2; 95% CI, 2.4 - 8.1); with a hospital stay of 15 to 21 days (odds ratio, 3.4; 95% CI, 1.6 - 7.0), 22 to 28 days (odds ratio, 4.3; 95% CI, 1.8 - 9.5), or 29 days or longer (odds ratio, 13.8; 95% CI, 8.3 - 24.1); with admission to the surgery (odds ratio, 2.0; 95% CI, 1.1 - 3.5), orthopedics (odds ratio, 2.5; 95% CI, 1.1 - 4.9), neurosurgery (odds ratio, 3.0; 95% CI, 1.5 - 5.9), or urology service (odds ratio, 3.9; 95% CI, 1.8 - 8.2); and with no surgical procedure (odds ratio, 1.6; 95% CI, 1.0 - 2.6)., Conclusions: The present study demonstrates that patient-related factors, such as age and length of stay, and treatment-related factors, such as no surgical procedure and admission to the surgery, orthopedics, neurosurgery, or urology service, are independent risk factors for inpatient falls. The results suggest that fall-prevention programs should target patients with these risk factors.

Clara cell 10-kD protein (CC10) exhibits potent antiinflammatory properties. G38A polymorphism was found in the CC10 gene. We investigated the genetic influence of the allele on the development of sarcoidosis using case control analysis in a Japanese population (265 sarcoidosis cases and 258 control subjects). The A allele frequency in sarcoidosis cases (45.1%) was significantly higher than healthy control subjects (34.9%, p = 0.0002). According to outcomes, we divided 223 patients with follow-up periods of 3 years or more into two subgroups (55 progressive and 168 regressive disease). The A allele frequency in patients with progressive disease was significantly higher than control subjects (odds ratio = 4.55; 95% confidence interval, 2.97-6.97; p < 0.0001), whereas that of regressive disease was not. The A/A genotypes had significantly lower bronchoalveolar lavage fluid CC10 levels than the G/G (nonsmokers, p = 0.0054, and smokers, p = 0.0045) and G/A genotypes (nonsmokers, p = 0.0022, and smokers, p = 0.0402). The reporter gene assay showed significantly lower reporter activities in the presence of interferon-gamma for the 38A construct than the 38G construct (p = 0.0177). The G38A polymorphism in the CC10 gene may influence protein expression and be associated with the development of progressive sarcoidosis.

To explore mechanisms governing the formation and remodeling of postsynaptic density (PSD), we used dissociated cultures of hippocampal neurons isolated from transgenic embryos expressing green fluorescent protein (GFP)-tagged PSD proteins PSD-Zip45 (Homer 1c) and PSD-95. Expression of GFP-tagged PSD molecules was stable, and the remodeling process of PSDs could be followed for >1 week. A higher expression level of GFP-PSD-Zip45 enabled us to quantitatively analyze the amount of PSD-Zip45 clusters during development. Repetitive imaging of the same cell populations between 11 and 17 d in culture revealed an increase of the average PSD-Zip45 cluster density from 0.32 to 0.73/microm. Newly generated dendrites rapidly acquired GFP-PSD-Zip45 clusters, and their density reached the level of parental dendrites within a few days. Temporal profiles of GFP-PSD-Zip45 cluster density showed a variety of patterns. Some dendrites showed a monotonous increase of clusters, whereas others showed complex patterns, including short decremental stages. Analysis of long-term remodeling of PSD-95-GFP clusters confirmed that the decremental stages were not specific to the PSD-Zip45 clusters. Comparison of the temporal profiles of the cluster density among neurons indicated synchronization of both GFP-PSD-Zip45 and PSD-95 clustering within individual cells. Furthermore, activation of cAMP-dependent protein kinase suppressed the decremental stages of cluster remodeling. These observations suggest the presence of signaling mechanisms that can induce synchronized addition or elimination of PSD proteins throughout dendritic arborization of a single neuron.

The axons of the retinal ganglion cells run on the diencephalotelencephalic boundary on their way to the tectum; however, they do not invade the telencephalon anteriorly. To investigate the mechanisms that prevent the retinal axons from entering the telencephalic territory, the effects of the telencephalic cells were examined on the outgrowth of the retinal axons in vitro; the retinal outgrowth was selectively inhibited by the cellular substrate derived from the telencephalon. The responsible factor for the selective inhibition was, furthermore, found in the telencephalic membranes and the fraction of peripheral membrane molecules from the telencephalon. Because the inhibitory effect was destroyed by chondroitinase ABC but not by heat, this inhibition was attributable to the carbohydrate chains of chondroitin sulfate proteoglycans (CSPGs) adhering to the membranes of the telencephalic cells. To understand the function of the telencephalic CSPGs on the retinal pathfinding in vivo, their carbohydrate chains [chondroitin sulfate glycosaminoglycan (CS-GAG)] were removed from the embryonic brains by intraventricular injection of chondroitinase ABC; the removal of CS-GAG resulted in an anterior enlargement of the optic tract. The results indicate that the telencephalic cells delimit the anterior border of the optic tract with their CSPGs and prevent the retinal axons from aberrantly entering the anterior territory.

We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue.

Using specimens from the posterior-superior quadrant of the human tympanic membrane, meatal skin, retroauricular skin and middle ear cholesteatoma, epidermal cell proliferation was studied by cultures in FC43 emulsion containing bromodeoxyuridine (BrdU), and cell death was detected by in situ labeling of nuclear DNA fragmentation (TUNEL staining). The culture of specimens with BrdU revealed labeling in the basal cell layer and/or the layer immediately above it. The counts of BrdU-labeled cells both at and beside the malleus handle and at the annulus were significantly higher than those in the tympanic membrane, meatal skin, retroauricular skin and cholesteatoma, indicating the existence of epidermal proliferation centers in the annulus and malleus handle. TUNEL-positive cells were observed in the uppermost layer of the epidermis, and counts of dying cells did not show any significant differences among specimens from the different areas. From these observations, we conclude that addition of newly proliferated cells at the proliferation center and uniform cell death cause epidermal cell migration over the tympanic membrane and ear canal. In addition, no proliferation center was seen in the epidermis of cholesteatoma, suggesting a disturbance of epidermal cell migration. Furthermore, BrdU-labeling at the margin of persistently perforated tympanic membranes from patients with chronic otitis media revealed that, at the perforation margin, the counts of BrdU-labeled cells were not higher than those of the normal tympanic membrane. In addition, a few BrdU-labeled cells were observed in the lamina propria and mucosal cell layer, indicating that persistent perforation of the tympanic membrane results from the failure of proliferating cells to increase at the margin of the perforation.

In Japan, the elderly population has progressively increased. It is therefore expected that various social services for the elderly will be demanded. As most of the elderly have hearing impairment due to presbycusis, it is difficult to communicate smoothly with them. To provide the various social services, it is necessary to investigate hearing acuity in the elderly. Accordingly, the Hearing Research Group, which belongs to the Research Project on Aging and Health in the Ministry of Health and Welfare of Japan, investigated the hearing acuity of people 65 years old, or more. One thousand one hundred ninety two subjects were divided into five groups, Group A consisted of 170 males and 216 females between 65 and 69 years old, Group B, 186 males and 158 females between 70 and 74; Group C, 147 males and 140 females between 75 and 79; Group D, 63 males and 61 females between 80 and 84; and Group E, 29 males and 22 females 85 years old or more. We examined the 175 subjects 80 years old or more. Therefore, it is considered that this study could indicate the present condition of hearing acuity of the elderly of Japan. The average hearing levels measured at seven frequencies (125, 250 and 500Hz, and 1, 2, 4, and 8KHz) were 35.0dB in group A, 42.1 in group B, 46.1 in group C, 52.1 in group D, and 55.6 in group E. There were no differences in the average hearing level between males and females in any group. The audiogram pattern indicated a gradually descending curve in most subjects in all groups. The average speech discrimination rate was 75.4% in group A, 70% in group B, 63.8% in group C, 59.7% in group D, and 52.1% in group E. The percentage of subjects showing a short increment sensitivity index of more than 70% was 45.2% in group A, 49.3% in group B, 47.9% in group C, 51.6% in group D, and 59.7% in group D. In conclusion, hearing loss due to aging tended to be more progressive at higher frequencies while hearing acuity of frequencies covering normal speech was preserved. However, the speech discrimination rate decreased relative to changes in the pure tone hearing level. It was considered that the pathology of hearing loss due to aging begins with retrocochlear changes and cochlear factors are added to retrocochlear changes with aging.

We investigated the clinical features of 64 cases of sudden deafness in patients more than 60 years of age. Forty-eight cases (75%) had profound deafness, 13 moderate and three mild deafness. The audiograms of 25 cases showed a flat pattern, 13 a gradually descending curve, and 13 total deafness. In 60 cases, the unaffected ear also had hearing impairment of variable severity. Fifty-one of these 60 cases demonstrated a physiological hearing threshold shift termed presbycusis in the unaffected ear. Hearing impairment in 35 cases (55%) was cured or improved by medical treatment including steroids. But in the majority of cases, the hearing threshold level of the affected ear did not improve above that of the unaffected ear when the unaffected ear had a hearing impairment. In particular, hearing impairment in five cases with total deafness in the unaffected ear did not improve. The elderly often had various systemic complications, including nine cases of diabetes and seven of hypertension. We treated patients with diabetes using steroids under the consultation of diabetic specialists. As a result, there was no case of complications induced by steroids. We consider the effect of treatment of sudden deafness in the elderly to be best judged in various degrees of hearing impairment in the unaffected ear.

The secretory portion of the apocrine sweat gland of the human external auditory meatus which is also called the ceruminous gland was observed by transmission and scanning electron microscopy. The secretory glandular cells contain a well developed smooth endoplasmic reticulum and Golgi apparatus. Cisternae of rough endoplasmic reticulum are often closely applied to large round mitochondria. These large mitochondria have no relationship to the secretory granules. Near the concave surface of the Golgi lamellae several tubules can be found. In these golgi-associated tubules a dark substance may accumulate to form specific large dense granules. Many less dense droplets or vacuoles may appear in these dark prosecretory granules and become liberated from their surface. Vacuoles formed in this manner then migrate to the apical cell surface and often discharge their contents into the gland lumen by the mechanism of exocytosis. Also, some of these vacuoles may be released into the lumen by the pinching off of small protrusions of cytoplasm, that is, they are released by the so-called apocrine secretory mechanism. Acid phosphatase activity was demonstrated not only in the dark prosecretory granules but also in clear vacuoles situated at the apical end of the cell and in the gland lumen. Such a histochemical finding may indicate that the secretory substance of the apocrine sweat gland may contain hydrolytic enzymes derived from lysosomes, which are the prosecretory granules of this gland, and these enzymes may play a role in dissolution and break down of the material extruded into the lumen by apocrine secretion. Apocrine secretory process of various sizes were observed on the luminal surface with the scanning electron microscope.

The myoepithelial cells of the human ceruminous apocrine gland were observed with transmission and scanning electron microscopes. The myoepithelial cells are long fibrous cells about 100-150 mum in length and 3-5 mum in width. They are arranged in parallel with each other, and their long axes are parallel to that of the secretory tubule itself. The tips of cells are often sharply pointed and their lateral tapering surface may be contiguous with adjacent cells forming a side-by-side contact, while other cells may have a blunt tip which is conjuncted with a similar tip of the next cell forming an end-to-end junction. The myoepithelial cells are joined to each other by desmosomes and there are also desmosomes at their junction with secretory cells. The outer surface of the cell abutting on the basal lamina has some exaggerated densities which are undoubtedly identical to the hemidesmosomes of epidermal cells. There are well developed foldings in the plasma membrane of the secretory cells, but the surface of the myoepithelial cells has very few foldings and projections. The relative shortage of intercellular attachment devices between the secretory and myeopithelial cells makes it easy to peel off the secretory cells to disclose the myoepithelium, a useful feature of scanning electron microscopy. The nucleus-containing part of the cell protrudes slightly upward and invades the secretory epithelium. The cytoplasmic rim surrounding the nucleus contains a small Golgi apparatus and some other organelles. The cytoplasm of the basal half of the cell contains closely packed myofilaments running parallel to the long axis of the cell. There is no definite arrangement of thin and thick myofilaments. Microtubules which often occur in pairs are arranged parallel to the myofilaments.