Septum-like Structures Research Articles

Intraoral Approach for Dental Implant Placement in Pneumatized Maxillary Sinuses with Postoperative Maxillary Cysts: A Report of Two Cases.

A postoperative maxillary cyst (POMC) is a delayed complication of the original Caldwell Luc operation, which was once widely performed to treat chronic rhinosinusitis. Two patients who had previously undergone Caldwell Luc operations desired dental implant treatment. In both cases, preoperative conebeam computed tomography (CBCT) revealed a POMC occupying the entire maxillary sinus on the side where the implants were to be placed. The residual bone height was 3-4 mm. Furthermore, the sinuses were divided into compartments by septum-like structures. An intraoral approach was applied for POMC enucleation and implant placement. The implants were placed with sinus floor penetration due to the small residual bone height. No bone substitute material was grafted in the sinus. Post-operative healing was uneventful. All implants were successfully osseointegrated and performed well (4 and 5 years for each patient). No sino-nasal complications were reported. Follow-up CBCTs showed that the exposed implant parts were covered by newly formed bone. The intraoral approach is a feasible option for implant placement in a pneumatized maxillary sinus with POMC.

Value of intraoperative pathological diagnosis in decision-making regarding resection of well-differentiated retropharyngeal liposarcoma: A case report.

Introduction and importancePreoperative diagnosis of well-differentiated liposarcoma (WDLS) in the retropharyngeal space is challenging because of the difficulty in obtaining a biopsy tissue specimen that will yield the microscopic findings necessary for a definitive pathological diagnosis. This report describes a case of retropharyngeal WDLS that was successfully diagnosed intraoperatively, which allowed radical resection.Case presentationThe patient was a 60-year-old man suspected of having a lipomatous tumor in the retropharyngeal space. On imaging, the tumor contained linear septum-like structures that were prominent behind the larynx. Pathological examination was performed using fine-needle aspiration cytology and core needle biopsy specimens. However, no malignant features were found. Given that partial biopsy of the retropharyngeal tumor by puncture was anatomically limited, we decided to collect appropriate tissue specimens for intraoperative pathological examination. During the operation, we biopsied the tumor, including the hard portion behind the larynx, anticipating inclusion of the septum-like structures seen on imaging. A pathological diagnosis of WDLS was successfully made and the tumor was completely excised.Clinical discussionThe fibrous septum with induration is important for intraoperative diagnosis of WDLS. The fibrous septum within the tumor was palpable as a rubbery hard portion.ConclusionWDLS in the retropharyngeal space could be successfully resected surgically by making a rapid intraoperative pathological diagnosis using appropriately selected tissue sampled from a hard portion of the tumor.

Three Cambrian fossils assembled into an extinct body plan of cnidarian affinity

The early Cambrian problematica Xianguangia sinica, Chengjiangopenna wangii, and Galeaplumosus abilus from the Chengjiang biota (Yunnan, China) have caused much controversy in the past and their phylogenetic placements remain unresolved. Here we show, based on exceptionally preserved material (85 new specimens plus type material), that specimens previously assigned to these three species are in fact parts of the same organism and propose that C. wangii and G. abilus are junior synonyms of X. sinica Our reconstruction of the complete animal reveals an extinct body plan that combines the characteristics of the three described species and is distinct from all known fossil and living taxa. This animal resembled a cnidarian polyp in overall morphology and having a gastric cavity partitioned by septum-like structures. However, it possessed an additional body cavity within its holdfast, an anchoring pit on the basal disk, and feather-like tentacles with densely ciliated pinnules arranged in an alternating pattern, indicating that it was a suspension feeder rather than a predatory actiniarian. Phylogenetic analyses using Bayesian inference and maximum parsimony suggest that X. sinica is a stem-group cnidarian. This relationship implies that the last common ancestor of X. sinica and crown cnidarians was probably a benthic, polypoid animal with a partitioned gastric cavity and a single mouth/anus opening. This extinct body plan suggests that feeding strategies of stem cnidarians may have been drastically different from that of their crown relatives, which are almost exclusively predators, and reveals that the morphological disparity of total-group Cnidaria is greater than previously assumed.

Highly Dynamic and Specific Phosphatidylinositol 4,5-Bisphosphate, Septin, and Cell Wall Integrity Pathway Responses Correlate with Caspofungin Activity against Candida albicans.

Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] activates the yeast cell wall integrity pathway. Candida albicans exposure to caspofungin results in the rapid redistribution of PI(4,5)P2 and septins to plasma membrane foci and subsequent fungicidal effects. We studied C. albicans PI(4,5)P2 and septin dynamics and protein kinase C (PKC)-Mkc1 cell wall integrity pathway activation following exposure to caspofungin and other drugs. PI(4,5)P2 and septins were visualized by live imaging of C. albicans cells coexpressing green fluorescent protein (GFP)-pleckstrin homology (PH) domain and red fluorescent protein-Cdc10p, respectively. PI(4,5)P2 was also visualized in GFP-PH domain-expressing C. albicans mkc1 mutants. Mkc1p phosphorylation was measured as a marker of PKC-Mkc1 pathway activation. Fungicidal activity was assessed using 20-h time-kill assays. Caspofungin immediately induced PI(4,5)P2 and Cdc10p colocalization to aberrant foci, a process that was highly dynamic over 3 h. PI(4,5)P2 levels increased in a dose-response manner at caspofungin concentrations of ≤4× MIC and progressively decreased at concentrations of ≥8× MIC. Caspofungin exposure resulted in broad-based mother-daughter bud necks and arrested septum-like structures, in which PI(4,5)P2 and Cdc10 colocalized. PKC-Mkc1 pathway activation was maximal within 10 min, peaked in response to caspofungin at 4× MIC, and declined at higher concentrations. The caspofungin-induced PI(4,5)P2 redistribution remained apparent in mkc1 mutants. Caspofungin exerted dose-dependent killing and paradoxical effects at ≤4× and ≥8× MIC, respectively. Fluconazole, amphotericin B, calcofluor white, and H2O2 did not impact the PI(4,5)P2 or Cdc10p distribution like caspofungin did. Caspofungin exerts rapid PI(4,5)P2-septin and PKC-Mkc1 responses that correlate with the extent of C. albicans killing, and the responses are not induced by other antifungal agents. PI(4,5)P2-septin regulation is crucial in early caspofungin responses and PKC-Mkc1 activation.

Subcutaneous intravascular papillary endothelial hyperplasia: ultrasound features and pathological correlation.

To describe grayscale and color Doppler ultrasound features of subcutaneous intravascular papillary endothelial hyperplasia (IPEH). The ultrasound appearances of ten histologically proven subcutaneous IPEH in ten patients (age range, 15-69 years; mean age, 38.2years; six females, four males) were reviewed retrospectively by two musculoskeletal radiologists. Color Doppler examination and surgical excision were performed in all cases. The correlations between the ultrasound and pathological features of the lesions were done. All ten cases were pathologically diagnosed as pure forms of IPEH. The mean size of the lesions was 1.3cm. The margins of the lesions were circumscribed in seven of ten patients. Three had lobular margins. The distinct internal septum-like structures were seen in seven of ten cases (70%). The vascularity was rich in three (30%), moderate in four (40%), and little in three (30%) of the ten cases. The most common vascular pattern was one or more vessels peripherally or both peripherally and centrally located in the lesion. The detectable origin vessel was noted in four of ten cases (40%). Although sonographic features of subcutaneous IPEH are non-specific, they should be included in the differential diagnosis of a small, well-defined, oval or elliptical, heterogeneous, hypoechoic soft tissue mass, showing a vascular pattern of one or more vessels in the lesion and variable vascularity. The presence of the internal septum-like structures and detectable origin vessel may be help to distinguish the lesion from the other soft tissue masses.

CT Features and Pathological Correlation of Primitive Neuroectodermal Tumor of the Kidney.

The purpose of the study was to analyze the computed tomography (CT) findings of primitive neuroectodermal tumor (PNET) of the kidney and correlate them pathologically. Ten cases of pathologically confirmed renal PNET were collected and retrospectively reviewed. The CT features that were analyzed include tumor size, shape, margins, density, nature of enhancement, presence of thrombosis, and metastasis, etc. These parameters were correlated with pathological findings and combined with literature review. The median age of the patients was 30years. CT images showed solitary, large, ill-defined, irregular, or lobulated heterogeneous mass. Invasive growth toward the renal cortex and pelvis with renal cortical interruptions were seen in eight cases with one case exhibiting invasion that extended beyond the renal capsule with soft tissue seen in the perirenal fat pace. The tumors were confined to the kidney contour with enlargement of kidney in six of the cases. Cystic changes with mural nodules were detected in three cases. Eight cases showed persistent moderate enhancement during the nephrographic phase. Irregular septum-like structures were seen in four cases. Thrombosis was detected in eight cases. Lymph node metastasis was detected in eight cases with bilateral lung metastasis in two and bone metastasis in one. Renal PNET is a rare highly aggressive disease affecting younger people. It should be considered as a strong differential when well confined, yet large tumors that cause enlargement of the kidney are seen and also when tumors expressing cystic changes along with mural nodules are seen. Although renal PNET has certain other characteristic CT features, pathological and immunohistochemistry report must also be sought for definitive diagnosis.

Characterization of giant spheroplasts generated from the aerobic anoxygenic photosynthetic marine bacterium Roseobacter litoralis.

We generated and characterized giant spheroplasts from the aerobic anoxygenic photosynthetic marine bacterium Roseobacter litoralis. The giant spheroplasts contained vacuole-like structures within the cells, mainly consisting of a single membrane. The in vivo absorption spectrum of the giant spheroplasts did not have peaks typically observed for bacteriochlorophyll a. The culture media pH decreased during the growth of the giant spheroplasts. The change in the pH profile for cells grown under light was no different from that for cells grown in the dark. These results showed that the R. litoralis giant spheroplasts formed lost their photosynthetic apparatus in culture. Most of the giant spheroplasts returned to their original size, likely via filamentous cells. The culture media pH increased during the growth of the filamentous cells. Some filamentous cells had septum-like structures. In such filamentous cells, DNA was separated. Initially, the color of the separated cells was white. Two weeks later, the cells changed to red in the dark, and the in vivo absorption spectrum of the cells had peaks typically observed for bacteriochlorophyll a. Our findings strongly suggest that the giant spheroplasts of R. litoralis can control the genetic information, return to their original cell size, and regain their original functions.

Four new Rhoicosphenia species from fossil deposits in India and North America

Rhoicosphenia Grunow is a common diatom in both freshwater and marine ecosystems and the genus can be found on nearly every continent. Most of the currently described taxa are extant and only six of 58 taxa are known from the fossil record. Also, reports from freshwater habitats of the Indian subcontinent are rare, with one report of Rhoicosphenia marina from marine ecosystems. Rhoicosphenia is common in freshwater and marine ecosystems of the USA and three fossils have been described from the Pacific Northwest. Four new species of Rhoicosphenia are described from fossil deposits in Gujarat, India and Oregon, USA. The new species from India are R. gandhii, a large, coarsely ornamented species and R. indica, a smaller species, both found in the same fossil deposit. The species from Oregon are R. reimeri, another large taxon, as well as R. patrickae, another small species, and both are found in the same fossil deposit. These new species descriptions highlight the recent trend of discovery of Rhoicosphenia diversity over the past decade. Finally, a discussion of the valvocopula structure in Rhoicosphenia is included with comparisons to septa and septum-like structures of other diatom genera.

Ultrastructure of Diatomella balfouriana with a discussion of septum-like structures in diatom genera

The ultrastructure of Diatomella balfouriana Greville collected from Île de la Possession, a sub-Antarctic island in the Crozet Archipelago, was studied using high-resolution scanning and transmission electron microscopy. The alveolate striae of the genus are subdivided by small vimines, presenting a unique feature never observed before in other diatom genera. The most striking feature of the genus is the presence of the septum-like structures projecting from the girdle bands. The term scalariform valvocopula is introduced for these structures to discriminate them from the septa present in several araphid and (at least one) raphid genera. The taxonomic position of the genus within the family Pinnulariaceae D.G. Mann is discussed based on the study of the structure of the alveolate striae.

Sonographic Identification of the Intracompartmental Septum in de Quervain's Disease

The intracompartmental septum in the first extensor compartment in patients with de Quervain's disease has been associated with disease development and prognosis. However, with the exception of surgical exploration, there is no way of detecting the septum. We evaluated the accuracy of sonography for identifying the intracompartmental septum in the first extensor compartment in patients with de Quervain's disease using surgical findings as the reference standard. We performed surgical release of the first extensor compartment in 43 wrists of 40 patients who were unresponsive to nonoperative treatment. In each case, a sonographic evaluation was performed before surgery by a radiologist and the sonographic and surgical findings were compared. Sonography identified the intracompartmental septum in 19 of the 19 septum-present wrists and absence of the septum in 23 of the 24 septum-absent wrists. The sensitivity of sonography was 100% (95% confidence interval, 80%-100%), its specificity 96% (95% confidence interval, 78%-100%), accuracy 98% (95% confidence interval, 87%-100%), positive predictive value 95% (95% confidence interval, 74%-100%), and negative predictive value 100% (95% confidence interval, 83%-100%). Sonography also identified septum-like structures in 15 of 37 (41%) asymptomatic contralateral wrists. Sonography is useful for detecting the intracompartmental septum in the first extensor compartment in patients with de Quervain's disease. Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Imaging Findings of Primitive Neuroectodermal Tumors of the Kidney

This study was designed to present the radiological imaging findings of a renal primitive neuroectodermal tumor (PNET). The study included 10 patients with pathologically proven renal PNETs. We assessed the size, margin, internal architecture, enhancement pattern, vein thrombosis, and presence of a metastasis of the tumors on multidetector-row computed tomography and magnetic resonance imaging. The mean age of the patients was 31 years. Patients were predominantly male (males-females, 8:2). The mean diameter of a renal PNET was 12.7 cm. All masses were well defined with a lobulated contour. Necrosis and hemorrhage were detected in 9 cases, respectively. All of the masses showed weak heterogeneous enhancement with multiple irregular septumlike structures. Eight of the masses had renal vein thrombosis, and 4 masses had extension into inferior vena cava. A lymph node metastasis was detected in 3 patients. A lung metastasis was detected in 4 patients, and 2 of the patients also had a bone metastasis. A renal PNET usually appears as a weakly enhanced large mass with multiple septumlike structures, peripheral hemorrhage, venous thrombosis, and accompanied with a distant metastasis in a young adult.

Ultrasonographic findings and natural history of intraductal papillary-mucinous neoplasms of the pancreas.

It is clear that the prevalence of malignancy is high in the main-duct type of intraductal papillary-mucinous neoplasm (IPMN). Branch-duct IPMNs include several histologic conditions such as carcinoma, adenoma, and hyperplasia. Intraductal papillary adenocarcinoma and papillary adenoma are characterized by papillary protrusions and thick septum-like structures in dilated ducts as delineated by ultrasonography. A solid mass showing a mixedecho pattern in the pancreatic parenchyma is a characteristic finding of invasive types of IPMN. The international guidelines for the management of branch-duct IPMNs suggest that the appearance of symptoms attributable to the cyst, the presence of intramural nodules, a cyst size greater than 30 mm, and dilation of the main pancreatic duct (>6 mm) are indications for resection. Based on the relationship between the height of a papillary protrusion and the diameter of a cystic dilated branch as well as on histological findings, branch-duct IPMNs with papillary protrusions more than 10 mm in height as shown by imaging should be resected, and it is not adequate to differentiate carcinoma from other lesions based on the diameter of cystic branches alone. A follow-up study on branch-duct IPMNs revealed that most papillary protrusions showed a slow increase in size or development of lateral spread, and that there was no development of cancer with stromal invasion during an average follow-up of 46 months. Therefore, the presence of intramural nodules alone should not be an indication for surgery. Also, patients without papillary protrusions or thick septum-like structures are not immediate candidates for surgery. Invasive adenocarcinoma can develop at a pancreatic site different from the area of interest showing cystic changes, with such invasion possibly being multicentric. Therefore, in patients with branch-duct IPMNs, attention should be paid to the entire pancreas when performing follow-up examinations.

Adenocarcinoma of the Lung Presenting as a Mycetoma With an Air Crescent Sign

An 89-year-old man was admitted to the hospital due to intermittent anterior chest wall pain for > 1 month. A chest radiograph obtained on November 9, 2004, demonstrated a mass with an irregular border, inside a thin-walled cavity, located in the superior segment of the left lower lobe. A chest CT scan revealed an irregular thin-walled cavity, 5.9 x 5.4 x 4 cm in size, with an air-crescent sign in the superior segment of the left lower lobe, and an intracavitary fungus ball-like mass. A bronchoscopic examination was performed, revealing only external compression of the left lower lobe bronchial lumen. Cultures from both the brushing cytology and brushing fungus specimens were negative. Since the patient was a heavy smoker and the chest radiograph obtained 23 months before had revealed no active pulmonary lesion, neoplastic growth was still highly suspected. Thus, an (18)F-fluoro-2-deoxyglucose positron emission tomography study was performed on November 25, and a mass with a slightly increased standard uptake value (3.17; cutoff value, 2.5) was found. He received a left lower lobe lobectomy on December 23, and a tumor with many septum-like structures connecting the surrounding pulmonary parenchymal tissue was found in the superior segment of the left lower lobe. The final pathologic diagnosis was adenocarcinoma of the lung (pT2N0M0). Thus, even though the chest radiograph and chest CT scan showed a typical air-crescent sign (ie, mass inside a cavity) favoring a mycetoma, the physician should still keep in mind that lung cancer may also unusually present in this way.

Nasal Reconstruction Using a Split Forehead Flap

The pedicle paramedian flap is the most common method used to reconstruct the nose, but secondary operations for debulking are required. In addition, this flap is always limited in length, which makes it hard to form the distal part of the nose. In this study, the authors suggest a split forehead flap with an oblique orientation designed to overcome the disadvantages of the paramedian flap. From their practice and review of the literature, the authors discovered that there is a cutaneous branch of the supratrochlear vessels that is set out around the orbital rim, travels subcutaneously, and has a rich anastomotic plexus with other vessels. Therefore, the authors designed a myocutaneous forehead flap with an oblique orientation to lengthen it and split it into two flaps: a muscle flap and a skin flap supplied by the supratrochlear vessels and their cutaneous branch, respectively. In six cases, the muscle flap was used to reconstruct the septum-like structure and wrap the cartilage framework; the skin flap was used to form a new nose. In five cases, the forehead flap was elevated and used as a superthin skin flap to form a new nose with distinct subunits without secondary debulking operations. This improved flap was used in 11 cases with 6 to 25 months of follow-up. In all cases, the authors observed the cutaneous branch of the supratrochlear vessels. All patients were satisfied with their new noses. This split forehead flap, with an oblique orientation design, has the advantages of achieving good restoration of nasal contour and building septum-like structures and reducing the number of operations.

CT and MRI findings in KIT-weak or KIT-negative atypical gastrointestinal stromal tumors

The large majority of gastrointestinal stromal tumors (GIST) can be diagnosed on the basis of KIT immunoreactivity. However, some atypical tumors show weak or negative KIT expression. We studied the imaging characteristics of atypical GIST, reviewing CT and MRI findings in ten patients (eight men, two women; mean age 59 years) with atypical GIST. Radiological studies were evaluated by two radiologists by consensus and included CT and MR imaging in all patients. Pathological diagnoses were made from surgery and confirmed by the polymerase-chain reaction (PCR) to amplify both exons of the c-kit gene and PDGFRA gene. The CT and MR examinations revealed a heterogeneous mass of the stomach containing cystic regions and soft tissue elements in all cases. All lesions were extraluminal masses and had an exophytic epicenter. On T1-weighted MR images soft tissue elements of the tumors were of homogeneously low- (n=3) or iso-signal intensity (n=7) compared with the liver parenchyma. On fast spin-echo T2-weighted MR images soft tissue elements of all tumors showed cystic regions of significantly high signal intensity interspersed with septumlike structures of low signal intensity. All lesions exhibited homogeneously (n=4) or heterogeneously (n=6) mild to moderate enhancement of soft tissue elements. Despite the relatively small number of patients CT and MRI findings of atypical GIST are a submucosal mass with soft tissue elements and cystic regions.

Mode of progression of intraductal papillary-mucinous tumor of the pancreas: analysis of patients with follow-up by EUS

We investigated the mode of progression of intraductal papillary-mucinous neoplasm of the pancreas (IPMN) in patients who underwent follow-up in order to elucidate the characteristics of malignancy and to establish an effective treatment strategy. Fifty-one patients with IPMN (branch-duct type, 47; main-duct type, 4) who had undergone follow-up study by endoscopic ultrasonography (EUS) were included (mean follow-up duration, 41.0+/-32.3 months; average number of EUS examinations performed during follow-up, 4.4). Chronological changes in EUS findings and histological findings of resected specimens were evaluated. Of the patients with the branch-duct type, only 2% showed enlargement of the dilated branches. In the main-duct-type group, an increase in size of the main pancreatic duct (MPD) was observed in 75% of the patients. In 14 patients with papillary protrusions, an increase in size and lateral spread was observed in 71% and 43%, respectively. No patients developed invasive cancer. In 15 patients who had thick septum-like structures (TSS), the development of papillary protrusions and that of invasive cancer were observed in 53% and 13%, respectively. Twenty-nine patients who had thin septum-like structures showed no change. Two patients with dense multilocular large cysts and TSS developed invasive cancer without change in the cystic lesions. One patient developed carcinoma with multifocal stromal invasion. Patients with branch-duct type IPMNs without papillary protrusions or TSS are not immediate candidates for surgery. Those who have small papillary protrusions have a benign course. It is recommended that patients with the large branch-duct type with TSS should undergo surgery. Attention should be paid to the entire pancreas when performing follow-up examinations in patients with branch-duct type IPMN, as invasive ductal adenocarcinoma can develop at a site in the pancreas different from that of the IPMN.

The septation apparatus, an autonomous system in budding yeast.

Actomyosin ring contraction and chitin primary septum deposition are interdependent processes in cell division of budding yeast. By fusing Myo1p, as representative of the contractile ring, and Chs2p for the primary septum, to different fluorescent proteins we show herein that the two processes proceed essentially at the same location and simultaneously. Chs2p differs from Myo1p in that it reflects the changes in shape of the plasma membrane to which it is attached and in that it is packed after its action into visible endocytic vesicles for its disposal. To ascertain whether this highly coordinated system could function independently of other cell cycle events, we reexamined the septum-like structures made by the septin mutant cdc3 at various sites on the cell cortex at the nonpermissive temperature. With the fluorescent fusion proteins mentioned above, we observed that in cdc3 at 37 degrees C both Myo1p and Chs2p colocalize at different spots of the cell cortex. A contraction of the Myo1p patch could also be detected, as well as that of a Chs2p patch, with subsequent appearance of vesicles. Furthermore, the septin Cdc12p, fused with yellow or cyan fluorescent protein, also colocalized with Myo1p and Chs2p at the aberrant locations. The formation of delocalized septa did not require nuclear division. We conclude that the septation apparatus, composed of septins, contractile ring, and the chitin synthase II system, can function at ectopic locations autonomously and independently of cell division, and that it can recruit the other elements necessary for the formation of secondary septa.

Septum-like structures in lipoma and liposarcoma: MR imaging and pathologic correlation.

To investigate the septum-like structures in predominantly lipomatous tumors, by correlating fat-suppressed MR images with histopathologic findings. The MR findings of three cases of well-differentiated liposarcoma (atypical lipoma), one case of lipoma-like component of dedifferentiated liposarcoma, and nine cases of lipoma were analyzed. T1-, T2-, and fat-suppressed T1-weighted images after Gd-DTPA administration were obtained. Surgical specimens from five patients (four with liposarcoma and one with lipoma) were also scanned with a MR unit, and compared with the pathologic findings. Enhancement features of lipoma and liposarcoma were well visualized on fat-suppressed T1-weighted images after Gd-DTPA administration. The septum-like structures of liposarcoma are thick and enhanced considerably, while septa of lipoma are thin and enhanced only slightly. Pathologically, the septum-like structures of liposarcoma contained muscle fibers and the septa of lipoma represented fibrous capsule. Identification of well-enhanced septa in a predominantly lipomatous tumor helps to differentiate malignant tumors from lipomas. As the septum-like structures of liposarcoma contain a skeletal muscle component the tumor might need more extensive surgical procedures including resection of adjacent muscles.

Formation of septum-like structures at locations remote from the budding sites in cytokinesis-defective mutants of Saccharomyces cerevisiae.

Cell wall structures that partition membrane-bound portions of cytoplasm were formed at sites along the peripheral wall when a cytokinesis-defective cell division cycle mutant (cdc3) of Saccharomyces cerevisiae was grown at a restrictive temperature. The appearance of these structures, as observed in electron micrographs, was similar to that of normal septa. Aberrant septa were also detected in cytokinesis mutants harboring mutations cdc10, cdc11, and cdc12, after growth at 37 degrees C. Formation of the abnormal septa was abolished by the introduction, in a cdc3-containing strain, of additional cell cycle mutations that precluded events leading to cytokinesis and cell division. These results showed that septum formation can occur in the absence of cytokinesis. Formation of the abnormal structures was controlled by the same sequences of cell cycle events as formation of normal septa but was not subject to the spatial controls that ensure association of the septum with the budding site.

Posttranscatheter embolization computed tomography in hepatocellular carcinoma. Evaluation of embolization effects.

The postcontrast CT scans and angiography of 26 lesions in 23 patients with hepatomas who underwent transcatheter arterial embolization therapy were reviewed. Newly developed low density and high density areas and gas were noted on CT scans of the tumors after embolization in 100, 8 and 58% of the lesions, respectively. The CT findings of residual tumors correlated well with those of follow-up angiography. When discrete smooth round low density zones were observed on CT, there was no residual neovascularity on follow-up arteriography. When there were nodular or thick septum-like structures in low density lesions, arteriography revealed residual tumor vascularity in the lesions. CT proved useful not only in evaluating the effects of embolization, but also in providing important information about residual tumors.