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Multiple Defects (multiple + defect)
Selected AbstractsGABAA -Receptor , Subunit Knockout Mice Have Multiple Defects in Behavioral Responses to EthanolALCOHOLISM, Issue 12 2001Robert M. Mihalek Background: The ,-aminobutyric acid type A receptors (GABARs) are involved in mediating some of the behavioral effects of beverage alcohol (ethanol). However, the unique pharmacological and behavioral responses conferred by each of the various receptor subunits are not well understood. Methods: To address the role of the GABAR , subunit in mediating ethanol responses, gene knockout mice that lack this subunit were tested for a variety of ethanol-induced behavioral responses. Results: Our results indicate that, compared with controls, ,-deficient mice (,,/,) have (1) reduced ethanol consumption, (2) attenuated withdrawal from chronic ethanol exposure, and (3) reduced anticonvulsant (seizure-protective) effects of ethanol. These mice demonstrate a normal anxiolytic response to ethanol and a normal hypothermic response to ethanol, and they develop both chronic and acute tolerance. Conclusions: These results further establish the link between GABARs and specific behavioral responses to ethanol and begin to reveal the role of the , subunit in these responses. [source] Planar cell polarity effector gene Fuzzy regulates cilia formation and Hedgehog signal transduction in mouseDEVELOPMENTAL DYNAMICS, Issue 12 2009Westley Heydeck Abstract Precise planar cell polarity (PCP) is critical for the development of multiple organ systems in animals. A group of core-PCP proteins are recognized to play crucial roles in convergent extension and other PCP-related processes in mammals. However, the functions of another group of PCP-regulating proteins, the PCP-effector proteins, are yet to be fully studied. In this study, the generation and characterization of a mouse mutant for the PCP effector gene Fuzzy (Fuz) is reported. Fuz homozygous mutants are embryonically lethal, with multiple defects including neural tube defects, abnormal dorsal/ventral patterning of the spinal cord, and defective anterior/posterior patterning of the limb buds. Fuz mutants also exhibit abnormal Hedgehog (Hh) signaling and inefficient proteolytic processing of Gli3. Finally, a significant decrease in cilia was found in Fuz homozygous mutants. In conclusion, Fuz plays an important role in cilia formation, Hh signal transduction, and embryonic development in mammals. Developmental Dynamics 238:3035,3042, 2009. © 2009 Wiley-Liss, Inc. [source] Generation of mice harboring a Sox6 conditional null allele,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2006Bogdan Dumitriu Abstract Sox6 belongs to the family of Sry-related HMG box transcription factors, which determine cell fate and differentiation in various lineages. Sox6 is expressed in several tissues, including cartilage, testis, neuronal, and erythropoietic tissues. Mice lacking Sox6 have revealed critical roles for Sox6 in several of these tissues, but their multiple defects and early lethality has limited studies in specific cell types and in postnatal mice. We show here that we have generated mice harboring a Sox6 conditional null allele (Sox6fl+) by flanking the second coding exon with loxP sites. This allele encodes wildtype Sox6 protein, is expressed normally, and is efficiently converted into a null allele (Sox6fl,) by Cre-mediated recombination in somatic and germ cells. Sox6fl+/fl+ mice are indistinguishable from wildtype mice, and Sox6fl,/fl, mice from Sox6,/, mice. These Sox6 conditional null mice will thus be valuable for further uncovering the roles of Sox6 in various processes in vivo. genesis 44:219,224, 2006. Published 2006 Wiley-Liss, Inc. [source] Sperm defects in mice lacking a functional Niemann,Pick C1 protein,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006Jun Fan Abstract The Niemann,Pick C1 (NPC1) gene encodes for a multiple membrane spanning protein, which regulates the trafficking of low-density lipoprotein-mediated endocytosed cholesterol. Mutation of the human NPC1 gene causes Niemann,Pick type C (NPC) disease. The Npc1NIH mice, a model of human NPC disease, bear a spontaneous mutation of the Npc1 gene, and are infertile. In this study, we have performed sperm analysis to search for the cause of male infertility in the Npc1NIH mouse. The number of cauda sperms in Npc1,/, mice was decreased roughly three-and-half-fold of that in wild-type mice. The decreased sperm number in Npc1,/, mice is due, at least in part, to partial arrest of spermatogenesis in the testes, as revealed by histological analysis. Compared to wild-type sperm, Npc1,/, sperm displayed a high frequency of morphological abnormalities, including tailless heads and aberrant heads. In the in vitro fertilization (IVF) assay using cumulus-intact eggs, Npc1,/, sperm failed to produce two-cell embryos. In the IVF assay where zona-free eggs were used, Npc1,/, sperm bound normally but could not fuse with the egg. Further analysis indicated that Npc1,/, sperms are drastically impaired in the binding to the egg zona pellucida, only 14% of the level of wild-type sperm. Moreover, on Npc1,/, cauda sperm, one-third of the total cyritestin protein was not proteolytically processed, while fertilin , was processed normally. Taken together, these results demonstrate that there are multiple defects in sperms from mice lacking a functional NPC1 protein, and these observed sperm defects may result in sterility. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Diagnosis and Management of Spontaneous Cerebrospinal Fluid-Middle Ear Effusion and Otorrhea,THE LARYNGOSCOPE, Issue 5 2004N. E. Brown MD Objectives/Hypothesis: Spontaneous leak of cerebrospinal fluid (CSF) into the middle ear can occur in adults without a history of temporal bone trauma or fracture, meningitis, or any obvious cause. Therefore, clues may be lacking that would alert the otolaryngologist that fluid medial to an intact eardrum, or fluid emanating from an eardrum perforation, is likely to be CSF fluid. A review of relevant medical literature reveals that herniation of the arachnoid membrane through a tegmen defect may be congenital, or CSF leak may occur when dynamic factors (i.e., brain pulsations or increases in intracranial pressure) produce a rent in the arachnoid membrane. Because tegmen defects may be multiple rather than single, identifying only one defect may not be sufficient for achieving definitive repair. Data on nine cases of spontaneous CSF leak to the ear in adult patients from four medical centers are presented and analyzed to provide collective information about a disorder that can be difficult to diagnose and manage. Study Design: Retrospective review of nine cases of spontaneous CSF middle ear effusion/otorrhea. Results: The majority of patients presented with symptoms of aural fullness and middle ear effusion. Many developed suspicious clear otorrhea only after insertion of a tympanostomy tube. Two patients had multiple defects in the tegmen and dura, and five patients had meningoencephaloceles confirmed intraoperatively. Five patients underwent combined middle cranial fossa/transmastoid repair. Materials used in repair included temporalis fascia, free muscle graft, Oxycel cotton, calvarial bone, pericranium, bone wax, and fibrin glue. Conclusions: CSF middle ear effusion/otorrhea can develop in adults without a prior history of meningitis or head trauma or any apparent proximate cause. Although presenting symptoms can be subtle, early suspicion and confirmatory imaging aid in establishing the diagnosis. Because surgical repair by way of a mastoid approach alone can be inadequate if there are multiple tegmen defects, a middle fossa approach alone, or in combination with a transmastoid approach, should be considered in most cases. [source] Effective coding in birth defects surveillance,BIRTH DEFECTS RESEARCH, Issue S1 2001Sonja A. Rasmussen Effective coding is critical to data collected by birth defects surveillance programs because subsequent use of the data depends on storage and retrieval of cases using codes. Hence, careful consideration needs to be given to the coding process. The primary goal of coding is to accurately, completely, and concisely represent infants with birth defects. Coding procedures need to accommodate the objectives of the surveillance program; for example, programs that focus on research may require different coding procedures from those that focus on linking infants to services. Several challenges exist in coding birth defects, including the need to distinguish infants with multiple defects and syndromes from those with isolated defects, and the need for strategies to code suspected defects for which confirmation is not available. Selection of a coding system by a birth defects surveillance program is central to the utility of the data collected. Most programs use a modification of the International Statistical Classification of Diseases and Related Health Problems-based (ICD) systems. This paper addresses ICD-based systems and the modifications used by many birth defects surveillance programs and presents examples of the problems in interpreting birth defects data because of inappropriate coding. Teratology 64:S3,S7, 2001. Published 2001 Wiley-Liss, Inc. [source] Continued occurrence of Accutane® -exposed pregnancies ,BIRTH DEFECTS RESEARCH, Issue 3 2001M.A. Honein Background Accutane® a teratogenic prescription drug licensed to treat severe, recalcitrant nodular acne. First-trimester pregnancy exposure can cause major birth defects. The manufacturer began a Pregnancy Prevention Program (PPP) in 1988; however, exposed pregnancies continue to occur. In 1996, the manufacturer began a direct-to-consumer advertising campaign, raising concerns of more exposed pregnancies. Methods We examined trends in Accutane use by reproductive-aged women. We also interviewed a series of 14 women in California who had recent Accutane-exposed pregnancies to identify opportunities for prevention. Results The estimated number of Accutane prescriptions for reproductive-aged women has more than doubled in the past 10 years; it is the most widely used teratogenic drug in the United States, with approximately 2.5 per 1,000 reproductive-aged women exposed to Accutane in 1999. One-half of the women interviewed reported seeing an advertisement for prescription acne treatment before taking Accutane. Eight of the 14 women used no contraception at the time of the exposed pregnancy; 13 of the 14 women did not use two forms of contraception. Four of the 14 women did not have pregnancy tests before starting Accutane. None reported seeing all PPP components, and four saw only the information on the pill packet. These 14 pregnancies resulted in four live infants who had no apparent birth defects, one live-born infant with multiple defects, four spontaneous abortions, and five induced abortions. Conclusions The increase in Accutane use observed among females may be exacerbated by advertising. Physicians and patients must use more caution with teratogenic prescription drugs. Teratology 64:142,147, 2001. Published 2001 Wiley-Liss, Inc. [source] The role of Gab family scaffolding adapter proteins in the signal transduction of cytokine and growth factor receptorsCANCER SCIENCE, Issue 12 2003Keigo Nishida The Grb2-associated binder (Gab) family adapter proteins are scaffolding adapter molecules that display sequence similarity with Drosophila DOS (daughter of sevenless), which is a substrate for the protein tyrosine phosphatase Corkscrew. Gab proteins contain a pleckstrin homology (PH) domain and binding sites for SH2 and SH3 domains. A number of studies in multiple systems have implicated Gab in signaling via many different types of receptors, such as growth factor, cytokine, and antigen receptors, and via oncoproteins. Recent studies of Gab1 and Gab2 knockout mice have clearly indicated an important role for Gabs in vivo. Gab1-deficient mice die as embryos with multiple defects in placental, heart, skin, and muscle development. Gab2-deficient mice are viable, but have a defect in the mast cell lineages and in allergic reactions. Given the apparently central role played by Gab signaling via many receptors, delineating the precise mechanism(s) of Gab-mediated signaling is critical to understanding how cytokines, growth factors, and oncoproteins mediate a variety of biological activities: cell growth, differentiation, survival and malignant transformation. [source] | |||||||||||||