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Sole Cause (sole + cause)
Selected AbstractsLow levels of Sry transcripts cannot be the sole cause of B6-YTIR sex reversalGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 1 2001Chung-Hae Lee Abstract Summary: Sry, a single-copy gene on the Y-chromosome, triggers the fetal gonad to begin testis differentiation in mammals. On the other hand, mutation or absence of Sry results in ovary differentiation and the female phenotype. However, cases of XY sex reversal in the presence of wild-type Sry exist in mice and man. One such example is the B6-YTIR mouse, whose autosomes and X-chromosome are from the C57BL/6J mouse (an inbred strain of Mus musculus molossinus), whereas the Y-chromosome is from a Mus musculus domesticus mouse originating in Tirano, Italy. The B6-YTIR mouse never develops normal testes and instead develops ovaries or ovotestes in fetal life. It has been suggested that low levels of Sry transcription may account for the aberrant testis differentiation in the B6-YTIR mouse. In this study, however, we observed relatively low levels of Sry transcripts not only in B6-YTIR but also in B6 mice, which develop normal testes. We conclude that low dosage of Sry transcripts cannot be the sole cause of sex reversal in the B6-YTIR gonad. genesis 30:7,11, 2001. © 2001 Wiley-Liss, Inc. [source] p.R254Q mutation in the aquaporin-2 water channel causing dominant nephrogenic diabetes insipidus is due to a lack of arginine vasopressin-induced phosphorylation,HUMAN MUTATION, Issue 10 2009Paul JM Savelkoul Abstract Vasopressin regulates human water homeostasis by re-distributing homotetrameric aquaporin-2 (AQP2) water channels from intracellular vesicles to the apical membrane of renal principal cells, a process in which phosphorylation of AQP2 at S256 by cAMP-dependent protein kinase A (PKA) is thought to be essential. Dominant nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin, is caused by AQP2 gene mutations. Here, we investigated a reported patient case of dominant NDI caused by a novel p.R254Q mutation. Expressed in oocytes, AQP2-p.R254Q appeared to be a functional water channel, but was impaired in its transport to the cell surface to the same degree as AQP2-p.S256A, which mimics non-phosphorylated AQP2. In polarized MDCK cells, AQP2-p.R254Q was retained and was distributed similarly to that of unstimulated wt-AQP2 or AQP2-p.S256A. Upon co-expression, AQP2-p.R254Q interacted with, and retained wt-AQP2 in intracellular vesicles. In contrast to wild-type AQP2, forskolin did not increase AQP2-p.R254Q phosphorylation at S256 or its translocation to the apical membrane. Mimicking constitutive phosphorylation in AQP2-p.R254Q with the p.S256D mutation, however, rescued its apical membrane expression. These date indicate that a lack of S256 phosphorylation is the sole cause of dominant NDI here, and thereby, p.R254Q is a loss of function instead of a gain of function mutation in dominant NDI. © 2009 Wiley-Liss, Inc. [source] Causes for the decline of suspended-sediment discharge in the Mississippi River system, 1940,2007,HYDROLOGICAL PROCESSES, Issue 1 2010Robert H. Meade Abstract Before 1900, the Missouri,Mississippi River system transported an estimated 400 million metric tons per year of sediment from the interior of the United States to coastal Louisiana. During the last two decades (1987,2006), this transport has averaged 145 million metric tons per year. The cause for this substantial decrease in sediment has been attributed to the trapping characteristics of dams constructed on the muddy part of the Missouri River during the 1950s. However, reexamination of more than 60 years of water- and sediment-discharge data indicates that the dams alone are not the sole cause. These dams trap about 100,150 million metric tons per year, which represent about half the decrease in sediment discharge near the mouth of the Mississippi. Changes in relations between water discharge and suspended-sediment concentration suggest that the Missouri,Mississippi has been transformed from a transport-limited to a supply-limited system. Thus, other engineering activities such as meander cutoffs, river-training structures, and bank revetments as well as soil erosion controls have trapped sediment, eliminated sediment sources, or protected sediment that was once available for transport episodically throughout the year. Removing major engineering structures such as dams probably would not restore sediment discharges to pre-1900 state, mainly because of the numerous smaller engineering structures and other soil-retention works throughout the Missouri,Mississippi system. Published in 2009 by John Wiley & Sons, Ltd. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 73JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003C Inglese Cryoglobulinemic neuropathy is probably the commonest form of vasculitic neuropathy in Mediterranean countries, as usually related to the widespread hepatitis C virus (HCV) infection. We describe the spectrum of manifestations in a large series of patients with cryoglobulinemic neuropathy, also analyzing the impact of comorbid factors, which are quite frequent in HCV-related mixed cryoglobulinemia. The cohort included 60 patients (10 men, 50 women) with peripheral neuropathy associated with mixed cryoglobulinemia as main or sole cause (type 2 in 36 cases, type 3 in 4, not typized in 20), HCV-related in all patients but 8 (3 men and 5 women). Median age of patients was 65 years (range 41,85), and median age at onset of neuropathy was 59 (range 40,84). Peripheral neuropathy represented an onset manifestation of mixed cryoglobulinemia in about half patients. The most frequent clinical pattern was pure sensory neuropathy in 40 patients, including 4 patients with prominent ataxia; sensory neuropathy was asymmetrical in distribution in 9 patients, and in 14 patients sensory action potentials (SAPs) of the sural nerve were normal, suggesting selective involvement of the small sensory fibers. The remaining patients had sensorimotor neuropathy (15 cases) and mononeuropathy multiplex (5 cases). Positive sensory symptoms and restless legs syndrome were the most common manifestations. Neurophysiological study showed axonal degeneration of varying severity in all patients. In 20 patients, additional causes of neuropathy were present, including type 2 diabetes (5 patients), glucose intolerance (6 patients), non-Hodgkin lymphoma (3 patients), and alcohol (2 patients). With respect with this subset of patients, in "pure" cryoglobulinemic neuropathy there was more often a pattern of sensory neuropathy (31/40 vs. 6/20; p = 0.001), with more frequent asymmetrical distribution (9 vs 0; p = 0.05) and small fiber involvement (11 vs 3). Severity of neuropathy, as judged on the basis of the Rankin scale and of neurophysiological changes, was similar in the two subgroups. Our study confirms that sensory neuropathy, often asymmetrical, is the most common clinical pattern in cryoglobulinemic neuropathy, and is consistently present in pure cryoglobulinemic neuropathy rather than in patients with other associated causes of neuropathy; in these latter, paradoxically, clinical and neurophysiological impairment seems not greater than in pure cryoglobulinemic neuropathy. [source] Chronic pain in Parkinson's disease: The cross-sectional French DoPaMiP surveyMOVEMENT DISORDERS, Issue 10 2008Laurence Nègre-Pagès PhD Abstract Pain is a frequent, but poorly studied symptom of Parkinson's disease (PD). DoPaMiP survey aimed to assess the prevalence of chronic pain in PD, to describe PD patients with chronic pain, and to record analgesic consumption. About 450 parkinsonian patients underwent structured standardized clinical examination and completed self-reported questionnaires in a cross sectional survey. Pains related or unrelated to PD were identified according to predefined criteria. About 98 patients with other chronic disorders than PD were examined to assess if pain was more frequent in PD than in this population. Two thirds parkinsonian patients (278 of 450) had chronic pain. Twenty-five patients with non-chronic pain (<3-month duration) were excluded from subsequent analysis. Twenty six percent (111 of 425) parkinsonian patients had pain unrelated to PD ("non-PD-pain", caused mainly by osteoarthritis), while 39.3% (167 of 425) had chronic pain related to PD ("PD-pain"). In this last group, PD was the sole cause of pain in 103 and indirectly aggravated pain of another origin (mainly osteoarthritis) in 64. Parkinsonian patients with "PD-pain" were younger at PD onset, had more motor complications, more severe depressive symptoms than those without pain or with "non-PD pain." "PD-pain" was more intense (P = 0.03), but was less frequently reported to doctors (P = 0.02), and was associated with less frequent analgesic consumption than "non-PD-pain." Pain was twice more frequent in PD patients than in patients without PD after adjustment for osteo-articular comorbidities (OR = 1.9; 95% CI 1.2,3.2). Chronic pain is frequent but underreported in PD. Awareness of this problem should be increased and the assessment of analgesic strategies improved. © 2008 Movement Disorder Society [source] Which comes first? psychogenic dizziness versus otogenic anxiety,THE LARYNGOSCOPE, Issue 10 2003Jeffrey P. Staab MD Abstract Objective: To investigate the hypotheses that physical neurotologic conditions may trigger anxiety disorders (otogenic pattern of illness), that psychiatric disorders may produce dizziness (psychogenic pattern), and that risk factors for these syndromes may be identified. Study Design: Retrospective review of all patients (N = 132) treated at a tertiary care balance center from 1998 to 2002 for psychogenic dizziness with or without physical neurotologic illnesses. Methods: All patients underwent comprehensive neurotologic and psychiatric evaluations with attention to the longitudinal course of symptoms and risk factors for psychopathology. Patients were grouped according to the condition first causing dizziness. Risk factors were compared across groups. Results: Three equally prevalent patterns of illness were found: anxiety disorders as the sole cause of dizziness (33% of cases), neurotologic conditions exacerbating preexisting psychiatric disorders (34%), and neurotologic conditions triggering new anxiety or depressive disorders (33%). Panic disorder and agoraphobia were significantly more prevalent than less severe phobias in the first two groups, whereas the opposite pattern existed in the third group (P < .0001). More patients in the first two groups had risk factors for anxiety disorders (P < .05). Depression was not a primary cause of dizziness in any patient. Vestibular neuronitis, benign paroxysmal positional vertigo, and migraine were the most common neurotologic conditions. Conclusions: These data support the hypothesis that physical neurotologic conditions may trigger psychopathology as often as primary anxiety disorders cause dizziness. A third pattern appears to be equally common wherein physical neurotologic conditions exacerbate preexisting psychiatric illnesses. Individuals at risk for anxiety disorders may be more likely to have primary psychopathology. [source] Differences in the expression of the ASIP gene are involved in the recessive black coat colour pattern in sheep: evidence from the rare Xalda sheep breedANIMAL GENETICS, Issue 3 2008L. J. Royo Summary Here we have tested the hypothesis of association between different levels of agouti signalling peptide (ASIP) mRNA and the recessive black coat colour in the rare Xalda breed of sheep. To deal with this task, we first tested the possible action of both the dominant black extension allele (ED) and a 5-bp deletion (X99692:c.100_104del; Adel) in the ovine ASIP coding sequence on the black coat colour pattern in 188 Xalda individuals. The ED allele was not present in the sample and only 11 individuals were homozygous for the AdelASIP allele. All Xalda individuals carrying the Adel/Adel genotype were phenotypically black. However, most black-coated individuals (109 out of 120) were not homozygous for the 5-bp deletion, thus rejecting the Adel/Adel genotype as the sole cause of recessive black coat colour in sheep. Differences in expression of ASIP mRNA were assessed via RT-PCR in 14 black-coated and 10 white-coated Xalda individuals showing different ASIP genotypes (Awt/Awt, Awt/Adel and Adel/Adel). Levels of expression in black animals were significantly (P < 0.0001) lower than those assessed for white-coated individuals. However, the ASIP genotype did not influence the ASIP mRNA level of expression. The consistency of these findings with those recently reported in humans is discussed, and the need to isolate the promoter region of ovine ASIP to obtain further evidence for a role of ASIP in recessive black ovine pigmentation is pointed out. [source] Population structure in an isolated Arctic fox, Vulpes lagopus, population: the impact of geographical barriersBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009KARIN NORÉN The genetic composition of a population reflects several aspects of the organism and its environment. The Icelandic Arctic fox population exceeds 8000 individuals and is comprised of both coastal and inland foxes. Several factors may affect within-population movement and subsequent genetic population structure. A narrow isthmus and sheep-proof fences may prevent movement between the north-western and central part and glacial rivers may reduce movement between the eastern and central part of Iceland. Moreover, population density and habitat characteristics can influence movement behaviour further. Here, we investigate the genetic structure in the Icelandic Arctic fox population (n = 108) using 10 microsatellite loci. Despite large glacial rivers, we found low divergence between the central and eastern part, suggesting extensive movement between these areas. However, both model- and frequency-based analyses suggest that the north-western part is genetically differentiated from the rest of Iceland (FST = 0.04, DS = 0.094), corresponding to 100,200 generations of complete isolation. This suggests that the fences cannot be the sole cause of divergence. Rather, the isthmus causes limited movement between the regions, implying that protection in the Hornstrandir Nature Reserve has a minimal impact on Arctic fox population size in the rest of Iceland. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 18,26. [source] Optic nerve blood flow in glaucomaCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2000Renuka Bathija FRACO FRACS Background: Glaucomatous optic neuropathy often occurs in the absence of elevated intraocular pressure and, conversely, elevated intraocular pressure may occur without associated damage of the optic nerve. These findings challenge the simple explanation of intraocular pressure being the sole cause of neural loss and have led to theories of ischaemic causes of the morbidity. This paper reviews the vascular anatomy of the optic disc, the factors that control its blood flow and the existing techniques for measurement of the blood flow. It also briefly discusses the possible role of apoptosis in glaucomatous visual loss. Method: Literature review. Conclusions: The posterior ciliary artery circulation is the main source of the blood supply to the optic nerve head with additional lesser supply via the central retinal artery and the choroidal circulation. There is considerable individual variation in the distribution of this circulation and complex regulatory systems govern its function. It is likely that microcirculatory changes in the vascular supply of the optic disc play a role in glaucoma, either as the primary abnormality or as a co-factor that increases susceptibility to damage from increased intraocular pressure through impaired auto-regulation. Clinical trials are currently in progress for the treatment of glaucoma with systemically administered agents that are antagonists of the receptors that mediate glutamine toxicity, a factor in the process of apoptosis. [source] | |||||||||||||