ABSTRACT
BACKGROUND: Necrotizing pancreatitis (NP) is caused by hypertriglyceridemia (HTG) in up to 10% of patients. Clinical experience suggests that HTG-NP is associated with increased clinical severity; objective evidence is limited and has not been specifically studied in NP. AIM: The aim of this study was to critically evaluate outcomes in HTG-NP. We hypothesized that patients with HTG-NP had significantly increased severity, morbidity, and mortality compared to patients with NP from other etiologies. METHODS: A case-control study of all NP patients treated at a single institution between 2005 and 2018 was performed. Diagnostic criteria of HTG-NP included a serum triglyceride level > 1000 mg/dL and the absence of another specific pancreatitis etiology. To control for differences in age, sex, and comorbidities, non-HTG and HTG patients were matched at a 4:1 ratio using propensity scores. Outcomes were compared between non-HTG and HTG patients. RESULTS: A total of 676 NP patients were treated during the study period. The incidence of HTG-NP was 5.8% (n = 39). The mean peak triglyceride level at diagnosis was 2923 mg/dL (SEM, 417 mg/dL). After propensity matching, no differences were found between non-HTG and HTG patients in CT severity index, degree of glandular necrosis, organ failure, infected necrosis, necrosis intervention, index admission LOS, readmission, total hospital LOS, or disease duration (P = NS). Mortality was similar in non-HTG-NP (7.1%) and HTG-NP (7.7%), P = 1.0. CONCLUSION: In this large, single-institution series, necrotizing pancreatitis caused by hypertriglyceridemia had similar disease severity, morbidity, and mortality as necrotizing pancreatitis caused by other etiologies.
Subject(s)
Hypertriglyceridemia/complications , Pancreatitis, Acute Necrotizing/etiology , Adult , Case-Control Studies , Female , Humans , Indiana/epidemiology , Male , Middle Aged , Pancreatitis, Acute Necrotizing/mortalityABSTRACT
PURPOSE: Hemipelvectomy is a major operation in which significant portions of the pelvic girdle and lower extremity are resected. The development of hernia following hemipelvectomy is a complex surgical challenge with limited published guidelines for management. We present our experience with three cases of hernia repair following internal hemipelvectomy and review the previously described ten cases of similar patients. METHODS: A systematic review of the current literature regarding hernias in the setting of hemipelvectomy was performed. A comprehensive search strategy on MEDLINE/PUBMED database searching for the key words of hemipelvectomy and hernia was used. RESULTS: There were 13 reported cases of incisional hernia after hemipelvectomy. The indication for hemipelvectomy was sarcoma in 77% of cases. The median time to presentation for hernia repair was 3 years following initial resection. Mesh repair was used in 77%. Identified risk factors for the development of incisional hernia included chemoradiation, wound infection, multiple operations, and weight gain. There was one event of hernia recurrence with a mean follow-up of 16 months. CONCLUSION: Hernia in the setting of hemipelvectomy is an infrequently reported problem. General principles in management are similar to all hernia repairs and include local approximation of tissues, avoidance of contamination or wound infection, and use of prosthetic mesh when local tissue is inadequate for a tension-free repair.
Subject(s)
Hemipelvectomy , Hernia, Ventral , Hernia , Hernia, Ventral/surgery , Herniorrhaphy/adverse effects , Humans , Neoplasm Recurrence, Local , Recurrence , Surgical Mesh/adverse effectsSubject(s)
Clostridioides difficile , Pancreatitis, Acute Necrotizing , Drainage , Humans , MorbidityABSTRACT
OBJECTIVES: To evaluate the safety and effectiveness of soft-tissue augmentation of the urethral sphincter with calcium hydroxylapatite (CaHA; Coaptite) compared with glutaraldehyde cross-linked bovine collagen (Contigen) in female patients with stress urinary incontinence due to intrinsic sphincter deficiency and without associated urethral hypermobility. METHODS: This 12-month prospective, randomized, comparative, multicenter, single-blind, parallel, clinical trial of CaHA and collagen for soft-tissue augmentation of the urethral sphincter in the treatment of stress urinary incontinence enrolled 296 women. Up to five injections were performed in the first 6 months of the trial. Twelve-month postinjection efficacy data were available for 231 patients. RESULTS: The results indicated that CaHA and collagen were both well tolerated in this study. No systemic adverse events were observed with either product. We used the Stamey Urinary Incontinence Scale to grade the improvement, which was the primary endpoint of the study. At 12 months, 83 (63.4%) of 131 CaHA patients compared with 57 (57.0%) of 100 collagen patients showed improvement of one Stamey grade or more (P = 0.34). More CaHA patients required only one injection (n = 60; 38.0%) during the study compared with the Contigen patients (n = 36; 26.1%; P = 0.034). Also, the average total volume of material injected during the course of the study was less for CaHA than for collagen (4.0 mL versus 6.6 mL, respectively; P <0.0001). CONCLUSIONS: The results of the study have demonstrated that Coaptite is an appropriate and well-tolerated treatment for patients with incontinence due to intrinsic sphincter deficiency. This new soft-tissue augmentation material has a good safety profile and appears to provide durable improvement.
Subject(s)
Collagen/therapeutic use , Durapatite/therapeutic use , Quality of Life , Urinary Incontinence, Stress/therapy , Adult , Aged , Animals , Cattle , Cross-Over Studies , Female , Follow-Up Studies , Humans , Middle Aged , Probability , Prospective Studies , Reference Values , Risk Assessment , Single-Blind Method , Treatment Outcome , Urinary Incontinence, Stress/diagnosis , UrodynamicsABSTRACT
The immune system of a healthy individual responds vigorously to foreign microbial antigens. However, all potentially immunogenic regions (determinants) within an antigen are not functionally of equal relevance in mediating host immunity against the pathogen. Moreover, some of these antigenic determinants are well processed and presented (immunodominant), while others are not revealed (cryptic) from the native antigen. Nevertheless, cryptic determinants are good immunogens in the pre-processed peptide form. Defining the factors influencing the dominance versus the crypticity of antigenic determinants is critical to advancing our understanding of the individual variations in host immunity to infection, autoantigens and vaccination. In this study based on a model antigen, hen eggwhite lysozyme (HEL), we describe that the major histocompatibility complex (MHC) haplotypes imprint and the non-MHC genes modify the dominance versus the crypticity of a specific antigenic determinant. Both the H-2(q)- and the H-2(d)-bearing mice raised potent response to native HEL, but responded differently to its determinant region 57-78, which was dominant in the H-2(q) but cryptic in the H-2(d) mice. The H-2(q)- but not the H-2(d)-bearing mice of three different genetic backgrounds yielded patterns of graded reactivity to epitope 57-78 showing the fine-tuning effect of the non-MHC genes. Interestingly, the F1 (H-2(q) x H-2(d)) mice retained the dominant response profile of the H-2(q) parent regardless of the contributing gender, and also responded to a new sub-determinant 61-75. These results highlight the genetic factors influencing the dominance/crypticity of a specific antigenic determinant.
Subject(s)
Epitopes, T-Lymphocyte/immunology , H-2 Antigens/genetics , Haplotypes , Major Histocompatibility Complex/genetics , Muramidase/immunology , T-Lymphocytes/immunology , Amino Acid Sequence , Animals , Antigens/chemistry , Antigens/genetics , Antigens/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/genetics , Genetic Predisposition to Disease , Histocompatibility Antigen H-2D , Mice , Mice, Mutant Strains , Muramidase/chemistry , Muramidase/genetics , VaccinationABSTRACT
BACKGROUND: Hemolysis is regularly encountered in clinical specimens and often interferes with a variety of laboratory test methods. Although not widely recognized, immunoassays based on nonisotopic detection systems can also be affected by hemolysis. For this reason, we investigated the effect of differing amounts of hemolysis across a range of values for several immunoassays on the Ortho-Clinical Diagnostics ECi and Roche Elecsys platforms. METHODS: Hemolysate was prepared from whole blood and spiked at varying concentrations into pooled patient serum samples for different analytes. RESULTS: Out of the 21 analytes tested, six (28.6%) exhibited significant increases or decreases in measured concentrations with increasing amounts of hemolysis. CONCLUSIONS: Although immunoassays are generally thought to be impervious to hemolysis interference, hemolysis can interfere in immunoassay testing platforms. For these reasons, we recommend that laboratories conduct hemolysis interference studies for all laboratory test protocols.
Subject(s)
Hemolysis , Immunoassay/methods , Blood Specimen Collection , Humans , Hydrocortisone/blood , Prostate-Specific Antigen/blood , Reagent Kits, Diagnostic , Testosterone/blood , Troponin I/blood , Troponin T/blood , Vitamin B 12/bloodABSTRACT
Mitotic PtK1 cells were arrested in mitosis with nocodazole to determine the effect of cytochalasin J (CJ) on kinetochore structure in arrested and nocodazole-released cells. In previous studies it was shown that CJ had a more pronounced effect on alteration of kinetochore structure and spindle microtubule (MT) architecture when applied during prophase or prometaphase. In this study, mitotic cells were treated at preanaphase for 10 min with 1 microg/ml nocodazole, or in 1 microg/ml nocodazole and 10 microg/ml CJ to allow for the advancement of the 'mitotic clock'. Thus it can be determined if either changes in the timing of mitosis, the maturation of the kinetochore, and/or the lack of MT connection to the kinetochore affects the ability of CJ to detach or alter the attachment of chromosomes to the developing spindle. Preanaphase cells treated with 1 microg/ml nocodazole for 10 min and released into 10 microg/ml CJ showed significant changes in MT organization and kinetochore structure. MTs nucleated at the centrosome are fragmented and kinetochore structure was significantly altered showing only two laminae with few MTs inserted into this structure. Preanaphase cells treated with 1 microg/ml nocodazole and 10 microg/ml CJ for 10 min and released into 10 microg/ml CJ showed similar, but more pronounced, effects on kinetochore structure and spindle MT organization. We interpret these results to suggest that CJ treatment has a greater effect on MT attachment and kinetochore structure in nocodazole pre-treated cells, where the kinetochore structure is mature and the mitotic cycle has been advanced.
Subject(s)
Cytochalasins/pharmacology , Kinetochores/drug effects , Mitosis/physiology , Animals , Cell Line , Kinetochores/ultrastructure , Microscopy, Electron , Microtubule-Organizing Center/drug effects , Microtubule-Organizing Center/ultrastructure , Microtubules/drug effects , Microtubules/metabolism , Microtubules/ultrastructure , Nocodazole/pharmacologyABSTRACT
We are conducting a large-scale, multiepoch, optical photometric survey [Centro de Investigaciones de Astronomia-Quasar Equatorial Survey Team (CIDA-QUEST)] covering about 120 square degrees to identify the young low-mass stars in the Orion OB1 association. We present results for an area of 34 square degrees. Using photometric variability as our main selection criterion, as well as follow-up spectroscopy, we confirmed 168 previously unidentified pre-main sequence stars that are about 0.6 to 0.9 times the mass of the sun (Mo), with ages of about 1 million to 3 million years (Ori OB1b) and about 3 million to 10 million years (Ori OB1a). The low-mass stars are spatially coincident with the high-mass (at least 3 Mo) members of the associations. Indicators of disk accretion such as Halpha emission and near-infrared emission from dusty disks fall sharply from Ori OB1b to Ori OB1a, indicating that the time scale for disk dissipation and possibly the onset of planet formation is a few million years.
ABSTRACT
In this study we examined the correlations of actual pre-morbid IQ scores (obtained from routine educational assessments) and estimated current IQ scores in 27 treatment-resistant schizophrenia patients. Pre-morbid (mean = 93) and current (mean = 83) IQ scores were significantly correlated (r = 0.807, P < 0.0001), while duration of illness (10-40 years) was unrelated to the magnitude of IQ score decline (r = -0.103, P = 0.575). These data suggest that pre-morbid IQ test scores are highly predictive of post-morbid scores.
Subject(s)
Antipsychotic Agents/therapeutic use , Schizophrenia/drug therapy , Adolescent , Adult , Double-Blind Method , Drug Resistance , Female , Humans , Intelligence , Male , Middle Aged , Wechsler ScalesABSTRACT
Examination of the subcellular localization of Dishevelled (Dsh) in fertilized Xenopus eggs revealed that Dsh is associated with vesicle-like organelles that are enriched on the prospective dorsal side of the embryo after cortical rotation. Dorsal enrichment of Dsh is blocked by UV irradiation of the vegetal pole, a treatment that inhibits development of dorsal cell fates, linking accumulation of Dsh and specification of dorsal cell fates. Investigation of the dynamics of Dsh localization using Dsh tagged with green fluorescent protein (Dsh-GFP) demonstrated that Dsh-GFP associates with small vesicle-like organelles that are directionally transported along the parallel array of microtubules towards the prospective dorsal side of the embryo during cortical rotation. Perturbing the assembly of the microtubule array with D(2)O, a treatment that promotes the random assembly of the array and the dorsalization of embryos, randomizes translocation of Dsh-GFP. Conversely, UV irradiation of the vegetal pole abolishes movement of Dsh-GFP. Finally, we demonstrate that overexpression of Dsh can stabilize beta-catenin in Xenopus. These data suggest that the directional translocation of Dsh along microtubules during cortical rotation and its subsequent enrichment on the prospective dorsal side of the embryo play a role in locally activating a maternal Wnt pathway responsible for establishing dorsal cell fates in Xenopus.
Subject(s)
Body Patterning , Cell Polarity , Embryonic Development , Phosphoproteins/metabolism , Trans-Activators , Xenopus Proteins , Adaptor Proteins, Signal Transducing , Animals , Biological Transport/drug effects , Biological Transport/radiation effects , Blastocyst/cytology , Blastocyst/metabolism , Body Patterning/drug effects , Body Patterning/radiation effects , Cell Differentiation/drug effects , Cell Differentiation/radiation effects , Cell Polarity/drug effects , Cell Polarity/radiation effects , Cytoskeletal Proteins/metabolism , Deuterium Oxide/pharmacology , Dishevelled Proteins , Embryo, Nonmammalian/drug effects , Embryo, Nonmammalian/metabolism , Embryo, Nonmammalian/radiation effects , Frizzled Receptors , Microtubules/drug effects , Microtubules/metabolism , Models, Biological , Nocodazole/pharmacology , Organelles/drug effects , Organelles/metabolism , Phosphoproteins/genetics , Rats , Receptors, G-Protein-Coupled , Receptors, Neurotransmitter/genetics , Receptors, Neurotransmitter/metabolism , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Ultraviolet Rays , Xenopus laevis/embryology , Xenopus laevis/metabolism , Zygote/cytology , Zygote/drug effects , Zygote/metabolism , Zygote/radiation effects , beta CateninABSTRACT
The genes encoding effector molecules of mature T cells, IL-2, perforin and IL-4, were found to be expressed in vivo in the most primitive subsets of thymocytes of adult mice. These subsets have previously been identified by their cell surface markers and by their expression of other T lineage-associated genes. While IL-2, perforin and IL-4 are expressed in distinct patterns, all three are expressed before the induction of RAG-1 and pre-TCR alpha mRNA expression, and are confined to subsets of cells that apparently have not yet undergone commitment to the T lineage. Thus, expression of T cell response genes appears to be one of the earliest markers of lymphocyte differentiation. Activation events marked by CD69 induction occur in these early cell types, but the response gene expression by these cells is separable from CD69 expression. IL-2 and perforin are induced again much later in thymocyte development, during TCR-dependent repertoire selection. At those stages, IL-2 protein and RNA levels per cell are higher, but the fraction of cells expressing IL-2 appears to be much lower than in the most immature stages. In addition, a striking feature of the immature populations is the robust IL-2 expression by presumptive immature NK cells. These findings are discussed in terms of the developmental origins of lineage specificity in T cell response gene regulation.
Subject(s)
Interleukin-2/genetics , Interleukin-4/genetics , Membrane Glycoproteins/genetics , T-Lymphocytes/immunology , Thymus Gland/cytology , Thymus Gland/immunology , Animals , Antigens, CD/genetics , Cell Differentiation , Cell Lineage , Flow Cytometry , Gene Expression Regulation, Developmental , Genes, RAG-1 , Killer Cells, Natural/metabolism , Lymphocyte Activation , Mice , Mice, Inbred C57BL , Mice, SCID , Perforin , Pore Forming Cytotoxic Proteins , Receptors, Antigen, T-Cell/analysis , Reverse Transcriptase Polymerase Chain Reaction , T-Lymphocytes/cytologyABSTRACT
In situ hybridization and immunohistochemistry were used to determine the spectrum of tissues in which interleukin-2 (IL-2) mRNA and protein are found in healthy, normal young mice. In neonatal animals, IL-2 is expressed specifically by distinct, isolated cells at three major sites: the thymus, skin, and gut. Based on morphology and distribution, the IL-2-expressing cells resemble CD3epsilon+ T cells that are also present in all these locations. Within the thymus of postweanling animals, both TcRalphabeta and TcRgammadelta lineage cells secrete "haloes" of the cytokine that diffuse over many cell diameters. Within the skin, isolated cells expressing IL-2 are seen at birth in the mesenchyme, and large numbers of IL-2-expressing cells are localized around hair follicles in the epidermis in 3-week-old animals. At this age, a substantial subset of CD3epsilon+ cells is similarly localized in the skin. Significantly, by 5 weeks of age and later when the CD3epsilon+ cells are evenly distributed throughout the epidermis, IL-2 RNA and protein expression are no longer detectable. Finally, within the intestine, IL-2 protein is first detected in association with a few discrete, isolated cells at day 16 of gestation and the number of IL-2 reactive cells increases in frequency through E19 and remains abundant in adult life. In postnatal animals, the frequency of IL-2-positive cells in villi exceeds by greater than fivefold that found in mesenteric lymph node or Peyer's patches. Overall, these temporal and spatial patterns of expression provide insight into the regulation of IL-2 in vivo and suggest a role for IL-2 expression distinct from immunological responses to antigen.
Subject(s)
Interleukin-2/biosynthesis , Intestines/immunology , Skin/immunology , Thymus Gland/immunology , Age Factors , Animals , Animals, Newborn , Cell Lineage , Fluorescent Antibody Technique, Direct , In Situ Hybridization , Interleukin-2/genetics , Interleukin-2/isolation & purification , Mice , Mice, Inbred C57BL , Mice, SCID , RNA, Messenger/isolation & purification , Receptors, Antigen, T-Cell, alpha-beta , Receptors, Antigen, T-Cell, gamma-delta , Receptors, Interleukin-2/isolation & purification , T-Lymphocytes/immunology , Tissue Distribution , WeaningABSTRACT
Variations in the way that data are entered in ED record systems impede the use of ED records for direct patient care and deter their reuse for many other legitimate purposes. To foster more uniform ED data, the Centers for Disease Control and Prevention's (CDC) National Center for Injury Prevention and Control is coordinating a public-private partnership that has developed recommended specifications for many observations, actions, instructions, conclusions, and identifiers that are entered in ED records. The partnership's initial product. Data Elements for Emergency Department Systems, Release 1.0 (DEEDS), is intended for use by individuals and organizations responsible for ED record systems. If the recommended specifications are widely adopted, then problems--such as data incompatibility and high costs of collecting, linking, and using data--can be substantially reduced. The collaborative effort that led to DEEDS, Release 1.0 sets a precedent for future review and revision of the initial recommendations.
Subject(s)
Emergency Service, Hospital , Medical Records/standards , Humans , Medical Record Linkage/standards , Medical Records Systems, Computerized/standardsABSTRACT
Variations in the way that data are entered in emergency department record systems impede the use of ED records for direct patient care and deter their reuse for many other legitimate purposes. To foster more uniform ED data, the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control is coordinating a public-private partnership that has developed recommended specifications for many observations, actions, instructions, conclusions, and identifiers that are entered in ED records. The partnership's initial product, Data Elements for Emergency Department Systems, Release 1.0 (DEEDS), is intended for use by individuals and organizations responsible for ED record systems. If the recommended specifications are widely adopted, then problems--such as data incompatibility and high costs of collecting, linking, and using data--can be substantially reduced. The collaborative effort that led to DEEDS, Release 1.0 sets a precedent for future review and revision of the initial recommendations.
Subject(s)
Emergency Service, Hospital , Medical Records/standards , Humans , Medical Record Linkage/standards , Medical Records Systems, Computerized/standardsABSTRACT
Detyrosinated and acetylated alpha-tubulins represent a stable pool of tubulin typically associated with microtubules of the centrosome and primary cilium of eukaryotic cells. Although primary cilium-centrosome and centrosome-Golgi relationships have been identified independently, the precise structural relationship between the primary cilium and Golgi has yet to be specifically defined. Confocal immunohistochemistry was used to localize detyrosinated (ID5) and acetylated (6-11B-1) tubulin antibodies in primary cilia of chondrocytes and smooth muscle cells, and to demonstrate their relationship to the Golgi complex identified by complementary lectin staining with wheat germ agglutinin. The results demonstrate the distribution and inherent structural variation of primary cilia tubulins, and the anatomical interrelationship between the primary cilium, the Golgi apparatus and the nucleus. We suggest that these interrelationships may form part of a functional feedback mechanism which could facilitate the directed secretion of newly synthesized connective tissue macromolecules.
Subject(s)
Aorta, Thoracic/cytology , Cartilage, Articular/cytology , Cilia/ultrastructure , Golgi Apparatus/ultrastructure , Muscle, Smooth, Vascular/ultrastructure , Tubulin/analysis , Acetylation , Animals , Dogs , Fluorescent Antibody Technique, Indirect , Image Processing, Computer-Assisted , Microscopy, Confocal , Microtubules/chemistry , Microtubules/ultrastructure , Morphogenesis , Protein Processing, Post-Translational , Swine , Tubulin/chemistry , Tyrosine/chemistry , Wheat Germ AgglutininsSubject(s)
Glycoproteins , Mitogens/chemistry , Proteins/chemistry , Proto-Oncogene Proteins/chemistry , Zebrafish Proteins , Animals , Binding, Competitive/physiology , Intracellular Signaling Peptides and Proteins , Ligands , Mitogens/antagonists & inhibitors , Mitogens/metabolism , Proteins/antagonists & inhibitors , Proteins/metabolism , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/metabolism , Wnt Proteins , XenopusABSTRACT
It has previously been demonstrated that treatment of mitotic PtK1 cells with 10-20 microg/ml cytochalasin J (CJ) blocks or slows chromosome motion and has a significant effect on spindle architecture [Snyder and Cohen, 1995: Cell Motil. Cytoskeleton 32:245-257]. Spindle microtubules (MTs) were shown to reorganize within the spindle domain, with kinetochore MTs (kMTs) reduced in number and non-kinetochore MTs (nkMTs) shown to splay outside the original spindle domain. In some cases, bundles of MTs were shown to be refocused away from the original spindle poles, creating the appearance of a multi-polar spindle. In this paper we use serial section electron microscopy, coupled with computer-assisted reconstruction techniques, to determine the rearrangement of spindle MTs and chromosome position following brief treatments of mitotic cells with 10-20 microg/ml CJ at various stages of mitosis. CJ treatment of prometaphase cells reduces the number of kMTs and the size and organization of the kinetochore lamina. Instead of kinetochore bundles of MTs aligned parallel to one another and running from kinetochore to pole, this class of MTs is highly fragmented. Non-kinetochore MTs are also highly fragmented, usually less than 2 microm long, and remain relatively straight over short distances, with some MTs arranged at an oblique angle to the longitudinal spindle axis. In approximately 30% of cells treated with CJ, the failure of a small number of chromosomes to attach to spindle fibers can be documented. These chromosomes show a significant change in the organization of the kinetochore laminae. Light microscopic analysis of cells treated with CJ reveals loss of chromosome congression, with chromsomes usually located at the periphery of the spindle and some completely detached from the spindle. Cells treated with 10 microg/ml CJ for 10 min and released into tissue culture medium show a resumption of chromosome motion within a few minutes, both during congression and anaphase. Where kMTs are inserted into kinetochores, chromosome motion is seen; where chromosomes fail to attach to the spindle, no chromosome motion is observed. Cells treated in metaphase show a delayed entry into anaphase and a reduced rate of anaphase A, with the arms of some chromosomes remaining in the interzone region. Our results suggest that CJ-sensitive molecules play a role in the organization of spindle MTs, as well as their functional association to kinetochores.
Subject(s)
Cytochalasins/pharmacology , Kinetochores/drug effects , Microtubules/drug effects , Spindle Apparatus/drug effects , Animals , Cell Line , Image Processing, Computer-Assisted , Kinetochores/ultrastructure , Marsupialia , Microtubules/physiology , Microtubules/ultrastructure , Spindle Apparatus/physiology , Spindle Apparatus/ultrastructureABSTRACT
Mitotic PtK1 cells were treated both during mid-anaphase and at furrow initiation with the potent microtubule (MT) stabilizing agent, taxol, to determine the role of MTs in the rate of cytokinetic events. Rates of cytokinesis (micron/min) were measured by changes in furrow diameter. Incubation of PtK1 cells during mid-anaphase with 5 micrograms/ml taxol slows the rate of cytokinesis by an average of 43%. Instead of furrow initiation to midbody formation taking an average of 10.7 min (1.6 microns/min), furrowing to midbody formation was completed in an average of 19.0 min (0.9 micron/min), which does not include the 7-min period between taxol application in mid-anaphase and furrow initiation. Application of 5 micrograms/ml taxol to cells at furrow initiation had a reduced effect on decreasing the rate of cytokinesis and midbody formation; furrowing to midbody formation took an average of 14.6 min (1.2 microns/min). These data suggest that delays in the rate of cytokinesis is dependent on the mitotic stage at which taxol is applied. Ultrastructural analysis shows that taxol treatment of anaphase cells prevents midbody formation during early G1, yet MT number and organization in the furrowed region is not significantly altered from untreated cells. There is little change in the organization and amount of contractile ring microfilaments, yet filaments are also found parallel to midbody MTs. Our results may be explained by the fact that taxol tends to stabilize MTs which probably affects the rate at which they depolymerize in the terminal phases of cytokinesis. Reduction in depolymerization rates of a stable population of MTs could serve to regulate the rate of cytokinesis.
Subject(s)
Cell Division/drug effects , Kidney/cytology , Microtubules/drug effects , Paclitaxel/pharmacology , Animals , Cell Line , Depression, Chemical , Kidney/metabolism , MacropodidaeABSTRACT
When overexpressed in Xenopus embryos, Xwnt-1, -3A, -8 and -8b define a functional class of Wnts (the Wnt-1 class) that promotes duplication of the embryonic axis, whereas Xwnt-5A, -4, and -11 define a distinct class (the Wnt-5A class) that alters morphogenetic movements (Du, S., S. Purcell, J. Christian, L. McGrew, and R. Moon. 1995. Mol. Cell. Biol. 15:2625-2634). Since come embryonic cells may be exposed to signals from both functional classes of Wnt during vertebrate development, this raises the question of how the signaling pathways of these classes of Wnts might interact. To address this issue, we coexpressed various Xwnts and components of the Wnt-1 class signaling pathway in developing Xenopus embryos. Members of the Xwnt-5A class antagonized the ability of ectopic Wnt-1 class to induce goosecoid expression and a secondary axis. Interestingly, the Wnt-5A class did not block goosecoid expression or axis induction in response to overexpression of cytoplasmic components of the Wnt-1 signaling pathway, beta-catenin or a kinase-dead gsk-3, or to the unrelated secreted factor, BVg1. The ability of the Wnt-5A class to block responses to the Wnt-1 class may involve decreases in cell adhesion, since ectopic expression of Xwnt-5A leads to decreased Ca2+-dependent cell adhesion and the activity of Xwnt-5A to block Wnt-1 class signals is mimicked by a dominant negative N-cadherin. These data underscore the importance of cell adhesion in modulating the responses of embryonic cells to signaling molecules and suggest that the Wnt-5A functional class of signaling factors can interact with the Wnt-1 class in an antagonistic manner.
Subject(s)
Cadherins/physiology , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/physiology , Trans-Activators , Xenopus laevis/embryology , Xenopus laevis/physiology , Zebrafish Proteins , Animals , Calcium-Calmodulin-Dependent Protein Kinases/pharmacology , Cytoskeletal Proteins/pharmacology , Female , Glycogen Synthase Kinase 3 , Immunohistochemistry , In Situ Hybridization , Microinjections , Protein Sorting Signals/antagonists & inhibitors , Protein Sorting Signals/genetics , Protein Sorting Signals/physiology , Proto-Oncogene Proteins/genetics , RNA/administration & dosage , RNA/genetics , Signal Transduction , Wnt Proteins , Wnt-5a Protein , Wnt1 Protein , Xenopus Proteins , Xenopus laevis/genetics , beta CateninABSTRACT
To determine whether signaling via CD122 (interleukin-2 [IL-2]/IL-15 receptor beta-chain) plays a role in regulating the expansion and differentiation of lymphocyte precursors, we have characterized its expression and evaluated its ability to influence the activity of developing lymphoid cells. A significant fraction of Sca1+Lin- hematopoietic stem cells in day 12 fetal liver were found to be CD122+. CD122-mRNA+ and IL-2-mRNA+ cells were also localized in embryo sections within pharyngeal blood vessels adjacent to and surrounding the thymic analgen. This distribution is consistent with the migration of CD122+ progenitor cells from the liver to the developing thymus where a majority of Sca1+ intrathymic T-cell progenitors were CD122+. Analysis of CD122 expression in the day 12 fetal liver revealed that the majority of B220+ cells were CD122+. Furthermore, CD122 expression was restricted to the earliest B220+ cells (CD43+CD24-; prepro B cells; fraction A) that proliferate vigorously to IL-2 in the absence of any stromal cells, but not to IL-15. Consistent with a role for the IL-2/IL-2R pathway in lymphocyte development is the progressive loss of B cells seen in IL-2-deficient mice. Together, these observations suggest that CD122 plays a role in regulating normal lymphocyte development in vivo.