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PubMed2001

Early development of the gubernaculum and cremaster sac in estrogen receptor knockout mice.

AIM exogenous estrogen causes gubernacular atrophy and cryptorchidism in fetal rodents. Mice with an estrogen receptor-alpha (ERalpha) disrupted gene mutation (alphaERKO) were studied to determine whether ablation of endogenous estrogen action, through ERalpha, had an effect on gubernacular development. Serial sagittal sections were made of the pelvis in fetal and day 7 postnatal wild-type and alphaERKO mice with the estrogen receptor-alpha "knockout" gene mutation. Wild-type (n = 24), heterozygote (n = 13) and alphaERKO mice (n = 12) were sacrificed at 16, 17 and 18 days fetal life and at 7 days postnatally. The size of the gubernaculum, cremaster muscle, cremaster sac, and the width of the sac at both ends in day 7 mice were quantitated by computer analysis. Visually and statistically the ERKO mice could not be separated from the wild-type mice during fetal life. At day 7 postnatally, a thicker cremaster sac was noted morphologically, and also a statistically significant difference was seen in the width of the cremaster sac at the sac's tip. Sac area, cremaster muscle area and the width of the sac at the sac's end did not differ significantly. Overall there is minimal phenotypic change observed in the alphaERKO mouse compared to wild-type at the early developmental stages investigated. However, at postnatal day 7, there is a difference in the width of the cremasteric sac tip. This suggests that the effect of ERalpha, and thus signaling on the developing gubernaculum, occurs late in development. Alternatively, an action from the recently discovered ERbeta may be involved. Exploration of a betaERKO and the double knock-out alphaERKO/betaERKO mouse should be informative in evaluating the effect of endogenous estrogens in gubernacular development.

Animals↗

PubMed2004

Variable sac behavior after endovascular repair of abdominal aortic aneurysm: analysis of core laboratory data.

OBJECTIVES: The behavior of the aneurysm sac after endovascular grafting has been the subject of significant speculation. The importance of sac behavior is manifested by the correlation between aneurysm size or size change and risk for rupture, and potentially further extrapolated to define the need for secondary intervention. This study was undertaken to define graft-specific differences and the effect of endoleak on sac remodeling. METHODS: Core laboratory data were obtained for three US Phase II clinical trials. Patients were included if they met anatomic inclusion criteria and underwent placement of the latest version of a bifurcated endovascular prosthesis. Unsupported Dacron (Ancure), supported Dacron (Zenith), and expanded polytetrafluoroethylene (Excluder) grafts were evaluated. Digitized images were electronically assessed for aneurysm size (area, maximum, minimum diameter) with National Institutes of Health Image software. Two blinded reviewers analyzed each radiographic study to ensure accurate image selection and establish the presence or absence of endoleak. A third reviewer adjudicated discrepancies. chi(2) analysis and mixed nonlinear modeling were used to analyze the results. RESULTS: Of 1506 patients evaluated, 723 (227 Ancure, 343 Excluder, 153 Zenith) met inclusion criteria for the study. Mean follow-up was 23.2 months (Ancure, 31.3 months; Excluder, 19.6 months; Zenith, 19.3 months). The incidence of any endoleak was 39.1% (Ancure, 58.1%; Excluder, 34.7%; Zenith, 20.9%; P <.001). Type of prosthesis, presence or absence of endoleak, and baseline size were determinants of rate of aneurysm shrinkage. Reduction in sac size was greatest with the Zenith graft, followed by the Ancure and Excluder grafts. Presence of endoleak had a moderating effect on rate of sac shrinkage with the Zenith and Ancure grafts; however, sac size increased in the presence of endoleak with the Excluder graft. Finally, baseline size was positively correlated with rate of aneurysm shrinkage. CONCLUSIONS: The behavior of the aneurysm sac depends on the type of prosthesis, presence or absence of endoleak, and baseline size of the sac. Differential sac behavior must be considered when determining the need for secondary interventions, timing follow-up studies, and assessing success or failure of endovascular repair.

Aorta, Abdominal↗

PubMed1999

Inguinal hernia revisited through comparative evaluation of peritoneum, processus vaginalis, and sacs obtained from children with hernia, hydrocele, and undescended testis.

BACKGROUND/PURPOSE: Histological structures of peritoneum, processus vaginalis, and sacs obtained from girls with inguinal hernia and boys with inguinal hernia, hydrocele, and undescended testis have been compared through immunohistochemical features to evaluate if any clue descriptive for the etiology of inguinal hernia exists. METHODS: Parietal peritoneums (n = 6), processus vaginalises (n = 4), female hernia sacs (n = 5), male hernia sacs (n 12), and sacs from hydrocele (n = 5) and undescended testis (n = 9) were stained with indirect immunoperoxidase method. Anti-CD9, CD26, CD29, CD31, CD36, CD44, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD54, CD55, CD56, CD62E & P, CD71, CD98, CD102, CD106, CD146, CD151 monoclonals and NFL-NPH, S-100 antiserums were used. The histological structures of each group of samples were identified and compared. RESULTS: Smooth muscle layers have been encountered within the walls of hernia sacs of both boys and girls. Although the hydrocele sacs have shown smooth muscle bundles distributed as patchy areas, smooth muscle bundles have been observed infrequently among sacs from patients with undescended testis. Peritoneum and processus vaginalis samples have been free of smooth muscle. CONCLUSIONS: Inguinal hernia during childhood seems to be related to the presence of smooth muscle within the wall of the sac. The smooth muscle bundles may have played a role both in prevention of obliteration and clinical outcome. Because the sacs associated with undescended testis are without smooth muscles, and herniation is not a frequent association, they may not share the same etiologic basis with inguinal hernia.

Child↗

PubMed1992

Inadequate inferior cul-de-sac in the anophthalmic socket.

A retrospective review of preoperative findings and postoperative results of conjunctival cul-de-sac fixation surgery performed on 12 patients with acquired anophthalmos and an inadequate inferior conjunctival cul-de-sac was performed. Patients with inadequate conjunctiva or other subconjunctival cicatricial shortening of the inferior cul-de-sac were not suitable candidates for conjunctival cul-de-sac fixation surgery and therefore were excluded from this retrospective study. Only those patients with adequate conjunctiva and loss of inferior cul-de-sac fixation to the lower eyelid retractor complex were selected. Clinical evaluation and theoretical anatomical analysis of this group preoperatively suggested that the absent inferior conjunctival cul-de-sac fixation could allow the intraconal orbital fat to migrate anteriorly, compromising the inferior fornix and prolapsing the conjunctiva of the cul-de-sac superiorly. Surgical correction required direct fixation of the conjunctival cul-de-sac to the periosteum immediately posterior to the inferior orbital rim. No externalized sutures or stents were needed to recreate the inferior conjunctival cul-de-sac. All 12 patients had improved ability to retain a prosthetic eye postoperatively. However, two patients had minimal postoperative lower eyelid retraction and an additional two patients had minimal lower eyelid entropion after surgery. Secondary surgery was not required in any patient.

Conjunctiva↗

PubMed1996

Glandular tumors of the lacrimal sac. Their histopathologic patterns and possible origins.

PURPOSE: To describe and characterize the primary lacrimal sac epithelial tumors of glandular origin, and to describe their possible source from glands in the lacrimal sac and nasolacrimal duct walls. METHODS: The authors conducted a clinicopathologic study on 14 patients with epithelial lacrimal sac tumors of possible glandular origin. In addition, they reviewed 35 surgical specimens of the lacrimal sac and nasolacrimal duct region and 13 cadaver specimens of the lacrimal sac region. RESULTS: Six of the tumors were benign: four were oncocytomas and two were pleomorphic adenomas. Eight of the tumors were malignant: three were oncocytic adenocarcinomas, three were adenoid cystic carcinomas, and two were adenocarcinomas. All tumors were from adults, ranging in age from 38 to 87 years. Twenty-eight of the 47 specimens of lacrimal sac and nasolacrimal duct region showed mixed glands of serous and mucous elements. CONCLUSIONS: Although rare, benign and malignant glandular lacrimal sac tumors should be considered in the differential diagnosis of lacrimal sac obstruction. Their possible origin is from the normal glands that exist under the lacrimal sac and nasolacrimal duct epithelium.

Adenocarcinoma↗

PubMed2002

Gestational sac diameter in very early pregnancy as a predictor of fetal outcome.

OBJECTIVE: To determine whether transvaginal sonographic measurement of gestational sac diameter in pregnancies 28-42 days from the last menstrual period can predict whether a pregnancy results in a normal term birth or a spontaneous miscarriage. DESIGN: Gestational sac diameter was measured during the 4th and 5th weeks of gestation from the last menstrual period in 67 women who had a total of 102 ultrasound scans. These pregnancies were followed until one of two outcomes occurred: term gestation (n = 32) or spontaneous miscarriage (n = 35). Gestational sac diameter as a function of gestational age was compared in each of the groups. RESULTS: The mean diameter of the gestational sac at 28-35 days from the last menstrual period among normal pregnancies did not differ significantly from that in those that subsequently miscarried (2.6 mm vs. 2.7 mm; P = 1.00). In pregnancies 36-42 days from the last menstrual period, the mean sac diameter was significantly different between the two groups (normal group, mean sac diameter, 8.2 mm and miscarriage group, mean sac diameter, 4.5 mm; P < 0.001). CONCLUSION: There is no difference in gestational sac diameter at 28-35 days from the last menstrual period in normal and abnormal pregnancies. However, smaller than expected sac diameter in pregnancies 36-42 days from the last menstrual period is predictive of spontaneous miscarriage.

Abortion, Spontaneous↗

PubMed2001

The pathogenesis and treatment of lacrimal obstruction: The value of lacrimal sac and bone analysis.

INTRODUCTION. The cause of primary acquired nasolacrimal duct obstruction (NLDO) has not been fully elucidated. In an attempt to determine the role of an inflammatory etiology, the pathology of nasolacrimal sac and bone specimens was assessed and correlated with clinical lacrimal variables. MATERIALS AND METHODS. Lacrimal sac and bone tissues from patients with known NLDO were sampled at the time of external dacryocystorhinostomy (DCR). Histopathological analysis was carried out to determine the presence and degree of inflammatory changes present in the tissues, and to correlate them with the clinical presentation. RESULTS. Of 104 cases analyzed, bony inflammatory changes were seen in 14% and lacrimal sac inflammatory changes in 94%. All cases of bony inflammation had accompanying lacrimal sac inflammation. The inflammatory changes were independent of the following variables: gender, duration of symptoms, a history of dacryocystitis, the presence of a lacrimal sac mucocele, the location of obstruction, and the presence of lacrimal sac calculi. CONCLUSIONS. Inflammatory changes are almost invariably present in all patients with NLDO. Its occurrence in bone is probably secondary to lacrimal sac inflammation. Although attempts are made to perform DCR surgery only in the absence of lacrimal sac inflammation, almost all cases exhibit subclinical inflammation. This may suggest that bypassing this 'critical area' of the sac-duct junction, as in a dacryocystorhinostomy, would be more reasonable than to re-canalize through an inflammatory obstruction.

Journal Article↗

PubMed2003

Finite element analysis of stresses developed in blood sacs of a pusherplate blood pump.

Mechanical circulatory support (MCS) devices are blood pumps that support or replace the function of the native heart. It is important to minimize the material stresses in the flexing blood sac or diaphragm in order to increase the duration of support these devices can provide. An axisymmetric finite element model of a pusherplate blood pump was constructed to evaluate the effect of various design parameters on the material stresses in a segmented poly(ether polyurethane urea) seamless blood sac. The design parameters of interest were the sac thickness, pump case wall taper, and radius of the sac between the pusherplate and pump case wall. The analysis involved a quasi-static analysis of the systolic ejection phase of the pump. The finite element solution suggested that the principal stresses and strains increased almost linearly with sac thickness. The pump case wall taper had the largest effect; decreasing the peak principal stresses by approximately 35% when the pump case was straight versus tapered. Lastly, the model demonstrated that the radius of the blood sac between the pusherplate and pump case wall had little or no effect on the magnitude of the blood sac stresses. Therefore, this study suggests that in order to minimize the stresses in a blood sac of a pusherplate blood pump, a straight pump case should be chosen with the thinnest sac.

Computer Simulation↗

PubMed2002

Lessons learned from ligation of indirect hernia sac: an alternative to reduction during endoscopic extraperitoneal inguinal hernioplasty.

BACKGROUND: During endoscopic totally extraperitoneal inguinal hernioplasty (TEP), complete reduction of the hernia sac is not always feasible because a sac extends into the scrotum or is adhesed. In such circumstances, ligation of the hernia sac appears to be a sound alternative to reduction. The present study was undertaken to evaluate the safety of sac ligation and the clinical results for patients who underwent ligation of an indirect hernia sac during TEP. PATIENTS AND METHODS: From September 1999 to July 2001, patients undergoing unilateral TEP for indirect inguinal hernia were recruited. Patients were divided into two groups. Group 1 (n = 65) underwent complete reduction of the hernia sac, whereas group II (n = 34) underwent ligation of the sac with a Vicryl suture followed by distal transection. Clinical parameters and outcome data were compared between the two groups of patients. RESULTS: Demographic features and hernia types between the two groups were comparable. The mean operative times of patients from groups I and II were 58 and 62 minutes, respectively (P = NS). Intraoperative complications occurred in two patients in group II, including a vas deferens transection and a gonadal vessel division. Comparison of the lengths of hospital stay, postoperative pain scores at rest and on coughing, rates of postoperative morbidity, and incidences of groin collection showed no significant differences between the two groups. CONCLUSIONS: Our findings highlight the importance of clear identification and protection of the vas deferens and gonadal vessels before transection of the ligated sac, particularly in patients with abundant preperitoneal adipose tissue. Ligation of an indirect hernia sac was associated with a higher incidence of intraoperative complications and should be performed with caution during TEP.

Case-Control Studies↗

PubMed1993

When multiple gestational sacs are seen on ultrasound, 'take-home baby' rate improves with in-vitro fertilization.

During a 5.5 year period, 309 clinical pregnancies were recorded in our in-vitro fertilization (IVF) unit. A single gestational sac was identified by early ultrasonography in 233 patients, while in 76 others, multiple gestational sacs were noted. 'Take-home baby' rate, in patients in whom multiple sacs were observed, was higher than that in patients with a single sac. Delivery of at least one live newborn occurred in only 73.8% of patients with a single sac, compared with 93.3% and 91.7% in patients with two and three gestational sacs, respectively. Conversely, the early and late abortion rates were decreased in patients with multiple sacs. Embryonic implantation rate, defined as the ratio of gestational sacs observed to the number of embryos transferred, was found to be a valuable prognostic factor for a live delivery, and can serve as a tool in assaying the prognosis of pregnancy detected by early sonography. The observation of a higher 'take-home baby' rate in cases with multiple sacs identified by ultrasound and with higher embryonic implantation rate, might be the result of a better embryo quality and/or improved uterine receptivity, promoted by a favourable hormonal milieu or by as yet unknown endometrial factors.

Abortion, Spontaneous↗

PubMed2004

Small intestinal submucosa aneurysm sac embolization for endoleak prevention after abdominal aortic aneurysm endografting: a pilot study in sheep.

PURPOSE: To percutaneously create an improved abdominal aortic aneurysm model of endoleak after endograft placement and to explore efficacy of small intestinal submucosal embolization of the residual aneurysmal sac for prevention of endoleaks. MATERIALS AND METHODS: Abdominal aortic aneurysm was created transluminally by over-dilation of a Palmaz stent in 12 sheep. Approximately 20% undersized endografts suspended between two stent-graft adapters were used to bridge the aneurysm in a manner that two lumbar pairs remained patent within the residual aneurysm sac. Size of the residual aneurysm sac was increased by placement of an undersized stent-graft consisting of damaged lyophilized small intestinal submucosal sheets sandwiched between two Zilver stents. In six sheep, residual aneurysm sacs were embolized by combining small intestinal submucosal sponge and small intestinal submucosal sheet pieces. The other six sheep served as the control group. Angiography performed immediately after the procedure was compared with follow-up angiography before the animals were killed at 1, 3, and 7 months. Gross and histologic examinations were also obtained. RESULTS: Aortic ruptures (n = 3) and dissections (n = 2) during aneurysm creation responded well to endograft placement. Eleven endografts were placed successfully, one was misplaced. The mean diameter of aneurysmal sac was 16 mm in the study and 15.2 mm in the control group. In the study group, in four sheep, the sac and seven pairs of lumbar arteries were occluded by embolization and remained obstructed by organized thrombus during the entire study. There were no type II endoleaks. Four type III new endoleaks developed without antegrade filling of lumbar arteries. In the control group, five animals had type I and II endoleaks at the initial studies. Only one sheep exhibited completely organized thrombosis of the aneurysmal sac and without endoleaks. In the other four sheep with partially organized sac thrombosis, endoleaks were unchanged. One type III endoleak occurred in this group. CONCLUSION: The combination of small intestinal submucosal sponge and small intestinal submucosal sheet pieces is a promising embolic material for occlusion of the residual sac after endovascular abdominal aortic aneurysm repair and for prevention of type II endoleaks.

Animals↗

PubMed2000

The sac-4 gene of Neisseria gonorrhoeae and co-existing chlamydial infection.

BACKGROUND/OBJECTIVES: Recently, the sac-4 gene in Neisseria gonorrhoeae was postulated to increase the risk of developing mixed gonococcal and chlamydial infection. The aims of this study were to determine the frequency of the sac-4 gene in a larger sample of isolates of different serovars and to assess the prevalence of sac-4 in gonococcal isolates from patients with and without coexisting chlamydial infection. METHODS: Isolates from 259 episodes of gonorrhoea were tested by a PCR assay for the sac-4 gene. The presence of co-existing chlamydial infection was determined from both laboratory and GUM clinical records. RESULTS: The overall prevalence of sac-4 was 57.5% (149/259). The prevalence was not the same in all serovars and ranged from 34.9% in serovar 1B2 to 100% in serovar 1B18. Exact logistic regression analysis indicated significant differences in sac-4 prevalence in isolates of different serovars. The prevalence of sac-4 was 69.5% (41/59) in gonococcal isolates from patients with co-existing chlamydial infection compared with 57.9% (62/107) for those without chlamydial infection. Exact logistic regression analysis showed that the slightly increased sac-4 prevalence among chlamydia positive patients (p = 0.2) virtually disappeared when serovar status was taken into account (p > 0.9). CONCLUSION: The sac-4 gene of the gonococcus does not increase the risk for mixed chlamydial infection.

Chlamydia Infections↗

PubMed1995

Imaging techniques in the diagnosis of lacrimal sac diverticulum.

Lacrimal sac diverticulum is a rare condition characterized by a cystic structure communicating with the sac. This abnormality may be directly demonstrated by dacryocystography only in a few cases; in the remaining cases, preoperative diagnosis may be arduous. We report 3 cases of lacrimal sac diverticulum. In all patients, symptoms were represented by a palpable mass in the lacrimal sac region, associated with permanent (case 1) or episodic (cases 2 and 3) epiphora. In the first case, CT-dacryocystography revealed an apparently solid mass causing inferior lacrimal obstruction, and ultrasonography disclosed a cystic space, not communicating with the sac. At surgery, a sac diverticulum was identified and excised. In the second patient, CT showed a homogeneous rounded mass, whereas a cystic character was revealed by T1-weighted MRI. Dacryocystography showed a lateral impression on the lateral wall of the sac. Ultrasonography revealed a cystic space communicating with the lacrimal sac. In the third case, ultrasonography demonstrated a diverticulum. CT is often unable to discriminate tumors from lacrimal cysts, both showing a parenchymal density. MRI can differentiate lacrimal cystic spaces from solid tumors by T1 intensity and by demonstration of their walls, but it is nonspecific for diverticula. Only dacryocystography and B-scan ultrasonography can reveal the narrow communication between the sac and the diverticulum. Observation is the recommended management for asymptomatic cases.

Adolescent↗

PubMed2002

The sac-4 gene of Neisseria gonorrhoeae correlates with gonococcal subtype not co-existing chlamydial infection.

We examined the hypothesis that the sac-4 gene of Neisseria gonorrhoeae varies with gonococcal subtype and that this could account for an earlier report that sac-4 increased the likelihood of co-infection with Chlamydia trachomatis. A polymerase chain reaction (PCR) assay was used to determine the prevalence of sac-4 in 435 gonococcal isolates. The prevalence of sac-4 was analysed in relation to chlamydial co-infection, serovar, auxotype, gender and sexual orientation. Although the prevalence of sac-4 was higher in isolates from patients with chlamydial co-infection (55%) than in those without chlamydial co-infection (42%) the difference was not significant (P<0.05). Statistically significant differences in association with sac-4 were, however, shown between various serovars and auxotypes. Dual classification based on auxotype/serovar (A/S) classes showed highly significant differences in sac-4 prevalence between groups: 95% in NR/1B18 and 8% in P/1B2 (P<0.001). Sac-4 was also significantly less common (P<0.05) in isolates from homosexual men (35%) than from heterosexual men (49%) or women (49.5%). Sac-4 appears to have an epidemiological association with gonococcal auxotype and serovar rather than a direct association with chlamydial co-infection.

Bacterial Proteins↗

PubMed1999

Magnetic resonance imaging evaluation of thecal sac diameters following laminectomy in the lumbar spine.

Sagittal magnetic resonance images (MRIs) from 20 patients who had postoperative persistent or recurrent low back pain were reviewed to study the thecal sac diameter at laminectomy sites. The thecal sac anteroposterior diameter was measured in three sites: the maximum AP diameter at the laminectomy site, and the proximal and distal levels to the laminectomy site. A comparison between the thecal sac AP diameter at laminectomy sites and the average diameter of both the proximal and distal levels was then made. Based on the measurements, the diameters of the thecal sac were divided into three groups. Patients in group A (5 cases) had a constriction (the thecal sac AP diameter at the laminectomy site was less than the average diameter of both the proximal and distal levels) of the thecal sac at the laminectomy site. Patients in group B (12 cases) had an expansion (the thecal sac AP diameter at the laminectomy site was more than the average diameter of both the proximal and distal levels) of the thecal sac. Patients in group C (3 cases) demonstrated no change. This study suggests that there was no correlation between the thecal sac AP diameter at laminectomy site and postoperative low back pain.

Adolescent↗

PubMed2005

[Clinical effect of amniotic membrane transplantation for reconstruction of conjunctival sac combined with orbital implantation].

OBJECTIVE: To observe the clinical effect of amniotic membrane transplantation for reconstruction of conjunctival sac combined with orbital implantation. METHODS: Twenty three cases suffered of conjunctival constriction were treated with amniotic membrane transplantation for reconstruction of conjunctival sac and combined with orbital implantation simultaneously. Buried suture of inferior conjunctival fornix via skin next to the inferior orbital margin was performed. The preserved amniotic membrane was flattened onto the conjunctival defect area and the superior and lower eyelid were closed with mattress suture. The eyelids were opened and stained with fluorescein test paper every week in order to observe the growth of conjunctival epithelium. Stitches were removed two months after surgery and the suitable prosthesis was made. RESULTS: Conjunctival epithelium migrated to the surface of the amniotic membrane and covered it completely in 20 cases four weeks after surgery. Amniotic membrane was dissolved and conjunctival epithelium could not cover the defect areas in the rest 3 cases. Two months after surgery, 4 eyes of degree I conjunctival sac constriction were all cured. In degree II conjunctival sac constriction, 8 eyes were cured and 2 eyes were improved. In degree III conjunctival sac constriction, 3 eyes were cured, 3 eyes improved, and 3 eyes failed. Among the failed eyes, one eye was underwent reconstruction of conjunctival sac again in six months. No exposure, secondary infection or symblepharon were occurred in 21 eyes with completed treatment, and these patients were satisfied with the good motility and the cosmetic results. CONCLUSION: Preserved amniotic membrane transplantation for reconstruction of conjunctival sac combined with orbital implantation is safe and effective in degree I and degree II conjunctival sac constriction, but less than perfect in degree III conjunctival sac constriction.

Adult↗

PubMed1991

Evaluation of normal gestational sac growth: appearance of embryonic heartbeat and embryo body movements using the transvaginal technique.

A cross-sectional transvaginal ultrasound study was conducted in 137 normal pregnancies with gestational ages ranging from 5-12 weeks. Several biometric measurements were obtained throughout pregnancy, including the three diameters of the gestational sac, the crown-rump length, and the yolk sac. In addition, the appearance of the embryo heartbeat and embryo body movements were evaluated. Linear relationships were found between the mean gestational sac diameters and gestational age (r = 0.911; P less than .00001) and between mean gestational sac growth and crown-rump length growth (r = 0.926; P less than .0001). A gestational sac could be identified at 5 weeks' gestation; embryo heartbeat was imaged when the mean gestational sac diameter measured 2 cm, and embryo body movements could be seen when the mean gestational sac diameter reached 3 cm. In the present study, embryo heartbeat was identifiable after 6 weeks and 4 days with a sensitivity of 100%, specificity of 93.1%, positive predictive value of 96.9%, and negative predictive value of 100%. The embryo body movements, which were absent before 7 weeks' gestation, were observed after 8 weeks' gestation with a sensitivity of 100%, specificity of 92.8%, positive predictive value of 94.3%, and negative predictive value of 100%. With identification by transvaginal sonographic evaluation, the following can serve as markers of normal embryo growth: a mean gestational sac diameter greater than 2 cm in the presence of the embryo heartbeat, or a mean sac diameter measurement greater than 3 cm in the presence of embryo movement.

Extraembryonic Membranes↗

PubMed1985

[Experimental induction and cytogenetic study of yolk sac tumors in Chinese hamsters].

The development of teratomas and yolk sac tumors from displaced yolk sac is well documented in rats and mice. However, precise mechanisms of induction and pathogeneses of these tumors still remain unknown. The present study was undertaken in order to elucidate whether this phenomenon is common to all rodents, to identify the origin of these tumors and to explore specific chromosomal changes in yolk sac tumors. Ten benign teratomas and two malignant tumors with teratomatous elements were obtained from 33 chinese hamsters after fetectomy, followed by displacement of yolk sac. The histological characteristics and the presence of laminin and alpha-FP suggested that the malignant tumors belonged to the category of yolk sac tumors. Similarities of electromicroscopic features observed in the tumor cells and the yolk sac of normal 12-day conceptuses suggested that the tumor originated from yolk sac cells. Chromosomal analyses of in vitro cell lines established from one of yolk sac tumors disclosed that the tumor was composed of clones with XX and XY sex chromosome constitution. The 1P+marker chromosome was identified as a consistent abnormality, which seemed to play an important role for the development of yolk sac tumors in chinese hamsters.

9,10-Dimethyl-1,2-benzanthracene↗