Sac-like Structure Research Articles

Laparoscopic management of early primary abdominal pregnancy

Abdominal pregnancy is a very rare condition with a high mortality rate. A 29-year-old woman with a history of primary infertility was admitted because of lower abdominal pain, bloody vaginal discharge, and positive urine pregnancy test. Transvaginal ultrasonography revealed a 27 x 25-mm mass containing a gestational sac-like structure located outside the uterus. At laparoscopy, a clot was revealed including chorionic villi, adherent to the peritoneum in the right vesicouterine pouch. This was removed along with the adherent peritoneum. Postoperative histology revealed invasion of chorionic tissues into peritoneum. Early diagnosis of an ectopic pregnancy by transvaginal ultrasonography enabled the laparoscopic management of early abdominal pregnancy.

Histological analysis of the egg capsule of the ovoviviparous polystomatid monogenean, Pseudodiplorchis americanus

Transmission of Pseudodiplorchis americanus is restricted to the brief period when its host, a desert toad, enters water to spawn. The parasite accumulates its entire annual reproductive output within an elongated uterus during the 10–11-month period of host hibernation. Embryos of P. americanus, at all stages of development, are retained within the uterus which eventually becomes packed with around 150 encapsulated infective larvae. Recently formed eggs, which comprise a fertilized ovum and 2–3 vitelline cells, are closely surrounded by a primary eggshell which stains positively for acidic proteins and keratin. Initially, during passage along the proximal uterus, the egg capsule is only 60 μm in diameter, but as it passes to the distal uterus it expands to 800 μm in diameter to accommodate the growing larva. Due to chemical alterations or complete replacement of the shell, the final (secondary) egg capsule is a large sac-like structure composed of elastin. The flexible nature of this shell maximizes the numbers of infective larvae which can be stored in utero. TEM studies have revealed this capsule to be composed of multi-laminate membranes with a specialized cytoplasmic lining involved in a unique mechanism for embryo nutrition. This is the first report of an elastintype eggshell within the Monogenea.

Comparative morphology of the peritremes of Varroa and Euvarroa (Varroidae), parasites of honey bees (Apidae)

The morphology of the peritremes of the genera Varroa and Euvarroa in the family Varroidae are described. In the genus Varroa, the moveable emergent peritreme lies flat along the venter laterad of legs III and IV but can be lowered 90° as necessary. The sclerotized peritremal groove consists of an ascending and a shorter descending arm thus forming a hook around the tip of the peritreme. The interior of the groove and stigmatal atrium are lined with micropapillae (=microtricheae). The remainder of the peritreme is a sac-like structure that is continuous with the body hemocoel. The peritreme of Euvarroa does not appear to be moveable or only slightly so and is positioned flush with the soft cuticle of the body laterad and somewhat posterior to legs IV. The sclerotized peritrematic groove is U-shaped and lined with micropapillae. The stigmata are open but are not continuous with the peritrematic groove as in Varroa.

Morphology of the Digestive and Reproductive Systems of Dalbulus maidis and Graminella nigrifrons (Homoptera: Cicadellidae)

The corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Homoptera: Cicadellidae) is the principal vector of maize rayado fino marafivirus, corn stunt spiroplasma and maize bushy stunt phytoplasma in tropical and subtropical areas of the Western Hemisphere. The black-faced leafhopper, Graminella nigrifrons (Fobes) (Homoptera: Cicadellidae) is the principal vector of maize chlorotic dwarf waikavirus in North America. The morphology of their digestive and reproductive systems was studied by light microscopy, and illustrations were made to aid in dissection and injection of pathogenic inoculum for various vector-pathogen relation studies. In both species, two salivary glands, located one on each side of the head, extend into the mesothorax. Each gland consists of principal and accessory glands. The former contains an anterior lobe and posterior lobe. Two types of acini are present in the anterior lobe, whereas the posterior lobe has four acini. The accessory glands of D. maidis and G. nigrifrons are very similar rod to elbow-shaped structures. The esophagus of both species is a narrow tube originating from the pharynx and extending to the anterior midgut below the filter chamber. The anterior midgut is a large sac-like structure extending from the metathorax through the entire length of the abdomen, and then ascends backward to the anterior of the midgut to form the filter chamber. The filter chamber of D. maidis has a more complex structure than that of G. nigrifrons. There are two pairs of Malpighian tubules in both species. The central tubule is formed from a pair of fused tubules within the filter chamber; the other tubules extend along the front of the hindgut. In G. nigrifrons the three tubules run parallel to each other along the top of the posterior midgut. In D. maidis, the central tubule and one tubule from the other pair run along the interior of the deep loop of the posterior midgut; the other tubule runs along the exterior of the loop. The ovaries of both species contain six ovarioles. Each ovariole consists of a terminal filament, a germarium, developing oocytes and eggs within follicles and a pedicle. The ovarioles contain six follicles. In G. nigrifrons each ovariole usually contains only one egg within the last follicle whereas the ovarioles of D. maidis often contain two eggs. The ovarioles open into the lateral oviduct, common oviduct and the vagina. The spermathecae open into the common oviduct. A collaterial gland and accessory glands are present. The male of both species has two lateral testes each with six follicles. A pair of accessory glands arise at the posterior of each seminal vesicle and open into the lateral ejaculatory duct.

Expression of CCAAT Enhancer Binding Protein-α (C/EBPα) in the Rat Ovary: Implications for Follicular Development and Ovulation

The development of follicles from the antral to the preovulatory stage in the mammalian ovary involves both proliferation and differentiation of cells. These processes are coordinated by endocrine, paracrine, and autocrine factors in a time- and cell-specific pattern. Each stage of development is characterized by expression of specific genes the products of which are involved in different cellular processes, e.g., signal transduction (cAMP-dependent protein kinases), steroidogenesis (cytochrome P450 enzymes). At the nuclear level, the signaling pathway from external stimuli converges to modify the mechanisms of transcription factors. One such factor, CCAAT enhancer binding protein-α (C/EBPα), participates in differentiation processes of several organs, e.g., liver, adipose tissue, and gut. We have previously demonstrated that C/EBPα is expressed in rat ovarian follicles in a cell-, time-, and hormone-specific manner. This increase in granulosa cells was concomitant with the more differentiated phenotype. The aim of the present study was to explore the function of C/EBPα in the rat ovary. To achieve this, the expression of C/EBPα in follicular cells was attenuatedin vivoby the local administration of antisense oligonucleotides (AS) into the ovarian bursa, i.e., the sac-like structure surrounding the ovary of immature rats. This administration resulted in an impaired response to subsequent injections of exogenous gonadotropins (PMSG, hCG) with an attenuated expression of C/EBPα protein and finally a decreased ovulation rate. Furthermore, the morphology of the AS-treated ovary was altered with large, oocyte-containing follicles at a time when ovaries exposed to sense (S) oligonucleotides demonstrated newly formed corpora lutea. AS also affected the expression of the proto-oncogene c-myc, which was elevated by this treatment. The administration of S was without effects. Thus, C/EBPα seems to be a necessary factor for follicular development in the rat ovary.

Role of endovaginal sonography in the diagnosis and management of ectopic pregnancy.

Although diagnostic laparoscopy is still considered the standard reference in the diagnosis of ectopic pregnancy (EP), use of high-resolution endovaginal sonography, in conjunction with qualitative serum assays of the beta subunit of human chorionic gonadotropin (beta-hCG), allows detection of earlier and smaller EPs. The most common endovaginal sonographic finding of EP (89%-100% of cases) is an extraovarian, round or elongated, solid tubal mass. A tubal ring (an extrauterine saclike structure) is the second most common finding (40%-68% of cases). Pelvic fluid may be present, but it is a nonspecific finding. An EP may have a pseudosac, which can be distinguished sonographically from the true gestational sac of an intrauterine pregnancy. Color Doppler techniques can complement endovaginal sonographic findings, but they should be performed only after a thorough real-time evaluation of the adnexal region. Current therapeutic options for EP include expectant management (ie, close follow-up), medical treatment (usually injections of methotrexate), and surgery. Accurate diagnosis with endovaginal sonography is the prerequisite to nonsurgical management, since surgery is the logical treatment if laparoscopy is used for diagnosis.

Characteristics of the genus Bacillidium Janda, 1928 (microspora, mrazekiidae) — Reinvestigation of the type species B. criodrili and improved diagnosis of the genus

Summary The cytology of a microsporidium identified as Bacillidium criodrili Janda, 1928, the type species of the genus Bacillidium, is described with emphasis on the ultrastructure. The host was Rhyacodrilus coccineus, not the type host Criodrilus lacuum. The living spores, which measure 2.1–2.7 × 21.7–24.4 μm, are approximately equally long but slightly more narrow than the sizes reported in the description. The exospore of the sporoblast releases the superficial, double membrane-like layer, which forms a sac-like structure, resembling a c. 28 nm thick individual sporophorous vesicle. The remaining exospore layer is a uniform, about 35 nm thick structure. The polaroplast, which occupies approximately the anterior 1/10 of the spore, has two lamellar regions, where the lamellae of the anterior region are more closely packed. The polar filament has a 404–495 nm wide anterior part, the “manubrium”, reaching approximately to the middle of the spore, a short section with decreasing width, and a final, 138–160 nm wide section ending in the posterior part of the spore. Membrane-lined rounded bodies, filled with uniform dense material, are present in the posterior region of the spore. Nuclei of all life cycle stages are coupled diplokaryotically. The cytological characteristics and the identification of the species are discussed, and an emended diagnosis of the genus Bacillidium is given together with a list of species.

Detection of retained products of conception following spontaneous abortion in the first trimester.

A retrospective analysis was performed to determine whether ultrasound could reliably rule in or out retained products of conception (POC) in women after first-trimester spontaneous abortions (miscarriages). Ninety-seven first-trimester pregnancies with pathologically proven results from dilatation and curettage (D&C) were studied within 7 days of ultrasound examination (60% within 2 days), either by the abdominal or a combination of abdominal and vaginal approaches. Cases were eliminated if there was clinical evidence of a spontaneous evacuation of POC during the interval between the ultrasound and the D&C. POC were diagnosed only if chorionic villi were evident pathologically. The pertinent ultrasound findings were related to the endometrium (thickness, echogenicity, a gestational saclike structure or a space-occupying collection). The results indicated that ultrasound could correctly diagnose POC in all of the cases by detecting a gestational sac or collection (77 cases), or a thickened endometrium of greater than 5 mm (6 cases). Ultrasound was less reliable in ruling out retained POC. When only a thin endometrial stripe of less than 2 mm was present, there was little likelihood of having POC (1 of 7 cases) with a moderately thick endometrium of 2 to 5 mm not diagnostic. Vaginal ultrasound added little new information and failed to change the ultrasound interpretation.

An ultrastructural study of ascospore delimitation and maturation in Ascodesmis nigricana using freeze substitution fixation

Fungi belonging to the class Ascomycetes are characterized by the production of sexually derived spores termed ascospores inside a microscopic, sac-like structure termed an ascus. In the Euascomycetidae, typically uninucleate spore initials are delimited within the ascus as the result of the invagination of membranes that arise from the so-called "ascus vesicle", a discontinuous cylinder of two closely spaced unit membranes that develops around the extreme periphery of the ascus. To date, there are conflicting data regarding the origin of the ascus vesicle. We therefore decided to address the problem using freeze substitution fixation. The advantages of this procedure over conventional chemical fixation protocols for preservation of ultrastructural details in fungi have been well-documented. In this study small pieces of dialysis membrane bearing developing ascocarps ofAscodesmis nigricanswere plunged into liquid propane and processed for TEM according to the procedures of Hoch and Mints et al.

Light and electron microscope studies on Jirovecia involuta sp. nov. (microspora, bacillidiidae), a new microsporidian parasite of oligochaetes in Sweden

The new microsporidium Jirovecia involuta is described, based on light and electron microscopy preparations. The host was the oligochaete Limnodrilus hoffmeisteri, collected from a stream in southern Sweden. All developmental stages are diplokaryotic. Mature spores are cylindrical, with a short tail-like projection of exospore material. The spore wall has a uniform exospore. The polaroplast has two regions, anteriorly with closely packed lamellae, posteriorly with tubules. The polar filament has a wide, straight anterior portion, and an approximately equally long, narrow posterior section, forming one coil. Each spore is enclosed in a double-layered sac-like structure, formed by the sporoblast from exospore material. The identity of the species and some traits on the ultrastructural cytology are discussed.

Early pregnancy complications: endovaginal sonographic findings correlated with human chorionic gonadotropin levels.

Endovaginal sonography results were compared with quantitatively determined human chorionic gonadotropin (hCG) levels in 84 women referred for early pregnancy complications. Of the 27 with normal intrauterine pregnancies, an intrauterine gestational sac was prospectively identified in one of five cases (20%) in which hCG levels were below 500 IU/L (Second International Standard), four of five (80%) with hCG levels of 500-1,000 IU/L, and all 17 with hCG levels above 1,000 IU/L. In comparison, 17 of the 26 women with ectopic pregnancies (65%) had hCG levels greater than 1,000 IU/L, and none of the 26 had an intrauterine gestational sac. Endovaginal sonography demonstrated an adnexal mass and/or a gestational sac-like structure in 16 of the 17 cases (94%) in which hCG levels were above 1,000 IU/L, compared with only three of the nine (33%) with lower hCG levels (P less than .01). These findings indicate that an intrauterine gestational sac should be normally visualized with endovaginal sonography when the hCG level exceeds 1,000 IU/L, and that visualization of an extrauterine gestational sac and/or adnexal mass is significantly more likely in ectopic pregnancies when the hCG level exceeds 1,000 IU/L.

The yolk sac in early pregnancy failure

An attempt was made to visualize the yolk sac in 845 patients scheduled for chorionic villi sampling. The distribution of yolk sac diameters and the interpolating growth curve up to 11 weeks of development were analyzed in 239 pregnant women who were delivered of normal infants. The highest visualizing rate of the yolk sac in normal pregnancies was 97 at 7 weeks of gestation. A total of 130 miscarriages occurred before chorionic villi sampling. In these cases, the diameter of the yolk sac versus crown-rump length tended to be larger than found in normal pregnancies. The visualizing rate of the yolk sac in miscarriages after the embryo had been formed was significantly higher in those women who demonstrated fetal heart activity (82.1%) than in those who did not (54.5%). On the other hand, the yolk sac was observed in 44% of miscarriages without a visible embryo. These findings suggest different types of missed abortion. An abnormal karyotype was observed in 23 of 29 chromosomal analyses performed on aborted specimens. An abnormal karyotype was observed in all eight cases with only a yolk sac-like structure within the gestational sac.

Cotton Leafperforator (Lepidoptera: Lyonetiidae): Female Reproductive System, Male Spermatophore, and Notes on Reproductive Biology

The female reproductive system and male spermatophore of the cotton leafperforator, Bucculatrix thruberiella Busck, were studied and described under magnification from laboratory-reared and wild individuals. Also, data were collected on time in copula, transfer of spermatophore, and sperm movement through the female reproductive system. As in most Lepidoptera, the female reproductive system consists of paired ovaries with four ovarioles per ovary, paired accessory glands, sperm duct, and bursa copulatrix. In virgin females the bursa copulatrix is a relatively large organ (ca. 0.76 mm in length and 0.24 mm in anterior by 0.36 mm in posterior width). During the copulatory process (ca. 66 min in copula), the bursa becomes greatly extended (ca. 1 mm in length by 0.92 mm in posterior width) and contains a very thin membraneous sac-like structure (spermatophore) that possesses both apyrene and eupyrene sperm. By 16 h after copulation the sperm have moved to the spermatheca and the spermatophore has become pear-shaped and opalescent in appearance.

Effect of anthelmintics on the early stage of Enterobius vermicularis.

In order to determine the susceptible age of Enterobius vermicularis to anthelmintics and to observe the chronologic growth of female E. vermicularis in man, experimental infections were done. About 500 eggs were challenged to 19 volunteers. After 4, 8, 16, 20, 24, 28, 32 and 35 days of infection, each case was treated by either mebendazole or pyrantel pamoate. On the 40th day of infection all cases including control were treated again to terminate the expermental infection and to evaluate the effect of previous treatment. Each case collected 3-day stools to harvest the expelled worms. The results could be summarized as follows: The infection rates of females were in range of 0.6~13.1% in control cases. Because the collected worms showed comparable growth and development by day, the worns were concluded to be derived from experimental infection. Cases that were treated with mebendazole on 4, 8 and 16 days after infection expelled 37.5%, 2.5% and 67.5% of the number expelled by a control case on the 40th day. Cases treated thereafter expelled no worms on the 40 days. Cases that were treated with pyrantel pamoates on 4, 8, 16, 24, 28, 32 and 35 days, expelled 90.7%, 25%, 45.3%, 8%, 2.7%, 5% and 29.3% of the number collected from control cases in respect. All the worms collected were females. The total body length increased consistently and comparably from the 20th day of infection. Those collected on the 20th day were 2.5~3.0 mm long with vigina, sac-like structure and strands of ovaries; 24 day-old worms may have short uterus, 28 day-old worms had long uterus without eggs, 32 day-old worms began to produce eggs, 35 day-old worms showed wide variations in egg deposit in uterus, and 40 day-old worms had uterus filled with eggs from vulva to anal levels. From the above results, it was inferred that the life span of female Enterobius vermicularis was longer than 40 days, and the developmental stages of worms younger than 16 days resisted considerably to both mebendazole and pyrantel pamoate.

A novel structure in the stomach and intestine of two species of Australian marsupial mice

A tubular or sac-like structure with a well defined lumen which occasionally contained parasites was found in the outer muscle wall of the small and large intestine in 32 out of 40 male and 35 of 40 female marsupial mice of the two species, Antechinus swainsonii and Antechinus stuartii (Macleay). A similar structure was also found in the muscle layers of the stomach in 5 marsupial mice of both species. The cellular matrix of the structure appeared to be composed of randomly organized macrophage-like cells and in one case there was evidence of an inflammatory reaction to parasites within the lumen. The origin of this tube is either vestigial or the result of reactive changes.

Light and electron microscopical observations on the male excurrent duct system of the common shrew (Sorex araneus).

In sexually active common shrews (Sorex araneus) the rete testis is a simple sac-like structure situated superficially between the equator and the anterior pole of the testis, and its epithelium glycogen-rich cells. In the ductuli efferentes, the tight junctions of the epithelial cells are poorly developed. The epididymis can be divided cytologically into initial, middle and terminal segments, and some variations are apparent in the fine structure of the principal cells throughout the duct. In the initial segment and in the most proximal part of the middle segment, mitochondrion-rich cells occur sporadically in the epithelium. The ductus deferens is divided into three anatomical regions, a tortuous pars epididymica, a straight middle portion, and an ampullary region. The distal half of the straight portion is distended, and appears to function, together with the terminal segment of the epididymis, as a sperm reservoir.

Internal Mechanism of Rorqual Feeding

This study elucidated the internal mechanism that enables rorquals (Balaenopteridae) to engulf a large volume of water prior to filtering it for prey. Anatomic experiments and observations were made on specimens of Balaenoptera acutorostrata, B. borealis , and B. physalus to assess the dynamic relationships of the tongue, nonlingual intermandibular lining, and cavum ventrale (a tissue cleft beneath the grooved, ventral body wall) as they would occur during engulfment. With the mouth empty, a distinct, centrally furrowed tongue was present in all three species. The nonlingual intermandibular lining ran outwards from the root of the tongue to attach along the ventral border of the mandibles. The cavum ventrale extended anteriorly beneath the tongue and nonlingual intermandibular lining from the cervico-thoracic region. By simple manipulation, the tongue could be transformed into a hollow, sac-like structure invaginating the cervical portion of the cavum ventrale. During this transformation, the nonlingual intermandibular lining was stretched posteriorly to completely cover the floor of the mouth. When the mouth of a suspended B. acutorostrata specimen (head only) was filled with water to simulate engulfment the tongue and nonlingual intermandibular lining expanded through the transected space of the cavum ventrale to form a capacious “oral sac.” The posteriodorsal wall of this sac was formed by what had been the tongue. Adaptations that enhance the expansibility of the oral sac include a highly elastic connective fiber matrix and a redundant surface created by epithelial corrugations and the tongue's central furrow. It is concluded that 1) during engulfment the tongue would initiate distension of the cavum ventrale by everting through the floor of the mouth between the cavum's inner and outer walls, 2) the everted, elastic tongue would act to enlarge the capacity of the mouth, and 3) the sac lining of the cavum ventrale at the end of engulfment would be created by the tongue and nonlingual intermandibular lining.

Glandular trichomes and sesquiterpene lactones of Artemisia nova (Asteraceae)

Abstract The leaves of Artemisia nova Nelson are covered with a dense layer of nonglandular trichomes that obstruct the observation of glandular trichomes on the leaf surfaces. An acid-staining technique was developed that eliminates interference from the nonglandular trichomes and stains the glandular ones red, allowing them to be seen under a light microscope. Using this method it was found that these glands develop on both leaf surfaces, except over veins, and cover 21–35% of the leaf surface area at densities of 50–70 per mm 2 . Mature glands are sac-like structure with a thin sheath or cuticle surrounding a clear transparent fluid. This fluid contains all of the sesquiterpene lactones present in the leaves, and some of the monoterpenes. These terpenoids were responsible for the red color of the glands after acid treatment.

The avian ovary is an open organ. A study of the lacunar system.

After an intraperitoneal injection of diluted yolk in female quails, young chicks or chick embryos (killed with minimal loss of blood), the absorption of a considerable quantity of yolk granules by the ovarian medullary lacunae can be demonstrated. This can be confirmed by the i.p. injection of killed Hela cells. From our investigation it may be concluded that the avian ovary, by the progressive expansion of its medullary lacunae, develops into a contractile sac-like structure with small openings (communicating with the peritoneal cavity) on its dorsal side. The lacunar system seems to function as an expansion room for the enlarging follicles (also the large pediculated follicles) and intervenes in follicle stalk formation. The relatively rapid uptake by means of an ovarian pumping mechanism of particles and fluid from the peritoneal cavity into the lacunae, suggests also that the latter play a role as diffusion chambers in the supply of nutritious substances to and elimination of wastes from the follicles.

The ultrastructural characterization of the tegument ofClonorchis sinensis (Cobbold, 1875) cercaria

The tegumental ultrastructure of the cercaria of the liver fluke, Clonorchis sinensis (Cobbold, 1875), was studied by scanning and transmission electron microscopy. The body surface is almost encircled by many rows of regularly arranged spines. The tegumental syncytium of the body contains many rod-shaped dense granules and central electron-lucent bodies, neither of which are present in the tail tegument. There are four rows of hooked teeth and modified spines on the oral cone. These teeth are differentiated morphologically and probably functionally from the other body spines. Disc-shaped papillae with long or short cilia are distributed on the body in a bilaterally symmetrical pattern dorsally and ventrally. There are 30 to 37 papillae with much longer cilia laterally. Four pairs of papillae were found on the tail. From their structure and location these papillae appear to have a mainly tango- or rheoreceptive function. Another type of sheathed papillae is situated around the oral sucker. The cuticular tegument is expanded laterally at the base of the tail, forming a characteristic sac-like structure.