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At least 523 records · Page 29Linked to original sources
PubMed2000

Hypertonic saline worsens infarct volume after transient focal ischemia in rats.

BACKGROUND AND PURPOSE: Hypertonic saline (HS) has been advocated as a hyperosmolar agent for the treatment of cerebral edema, especially after traumatic brain injury. We tested the hypothesis that continuous intravenous HS administered during reperfusion from transient focal cerebral ischemia attenuates infarct volume. METHODS: Halothane-anesthetized male Wistar rats were subjected to 2 hours of middle cerebral artery occlusion (MCAO) by the intraluminal occlusion technique. At the onset of reperfusion, rats received a 10-mL/kg intravenous bolus of 0.9% saline (SAL, n=8) or 7.5% SAL (chloride:acetate 50:50, n=8) followed by a continuous infusion for 22 hours. In a second series of experiments, ischemic damage was determined in cohorts treated with equivolumetric 3% saline (n=8) or 20% mannitol (n=8). In a third series, regional cerebral blood flow was measured ([(14)C]iodoantipyrine autoradiography) at 6 hours of reperfusion in 7.5%-SAL-treated (n=5) or SAL-treated (n=5) animals. RESULTS: In SAL rats, serum Na(+) was 137+/-3 and 138+/-2 mEq/L (mean+/-SEM) at baseline and 22 hours of reperfusion, respectively. In 7.5% SAL, serum Na(+) was 136+/-2 and 154+/-2 mEq/L at baseline and reperfusion, respectively. Physiological variables and reduction in laser-Doppler signal during MCAO and early reperfusion were not different between the 2 treatment groups. Cortical infarct volume was larger in 7.5%-SAL-treated rats (121+/-14 mm(3); 30+/-3% of contralateral cortex; P<0.05) than in SAL (64+/-15 mm(3); 16+/-4% of contralateral cortex). Striatal infarct volume was unchanged by HS therapy. Ipsilateral cortical tissue volume was increased relative to the contralateral side (by 26+/-5% with SAL; by 41+/-5% with 7.5% SAL). In contrast, ischemic damage was unaffected by 3%-SAL or 20%-mannitol treatment compared with SAL. Regional cerebral blood flow during reperfusion was heterogeneous in all animals, but there was no evidence of postischemic hypoperfusion or blood flow maldistribution in 7.5%-SAL-treated animals. CONCLUSIONS: These data demonstrate that hypernatremia resulting from postischemic HS infusion worsens cortical infarct volume in transient focal cerebral ischemia. The deleterious effect is not linked to exacerbation of delayed hypoperfusion during early reperfusion (6 hours); however, blood flow defects at later recovery time points remain to be excluded. These results may have implications for HS therapy in clinical ischemic stroke.

Animals↗
PubMedDate not supplied

Pyramidal tract responses (PTR) during hypoxia and hypotension.

In rats with unilateral carotid artery ligation pyramidal tract responses were studied during hypoxia and during trimethaphan-induced hypotension. Observations on EEG activity during hypoxia suggest that unilateral carotid artery ligation produces a more severe perfusion defect in lateral portions of the hemisphere. During hypoxia and during trimethaphan-induced hypotension indirect PTRs disappeared first from the hemisphere on the side of carotid artery ligation and next from the opposite hemisphere. This was followed by loss of direct PTRs in the same order. Animals could not be resuscitated once the direct PTR from the non-ligated hemisphere had disappeared. Hypotension appears to be a late contributing factor in impairing electrocerebral activity during hypoxia in this study.

Animals↗
PubMed1984

Down's syndrome: nutritional intervention.

Down's Syndrome patients are known to be of short stature, prone to infections, autoimmune disease, hypothyroidism, leukaemia, heart defects and later Alzheimer's disease. They tend to have older mothers, like Alzheimer's disease patients. The latter tend to have sibs with either Down's Syndrome or lymphoma/leukaemia. Evidence, looking at 28 Down's Syndrome patients, suggests that multiple food allergies, gluten-gliadin sensitivity or intolerance are causing a coeliac disease-like picture with a malabsorption state for essential vitamins, minerals and severe autoimmune disease. It is hoped that missed gluten-gliadin sensitivity or intolerance with or without coeliac disease will be considered as a cause of abnormal oogenesis and spermatogenesis resulting in trisomy 21 and other aneuploidies. The mechanism most likely is low B1 interfering with sufficient release of cAMP for normal meiosis. Alternatively exorphins and peptides from foods may suppress prostaglandin E1 synthesis, or food sensitivities may alter toxic metal absorption mechanisms, which are thought to play a role in the development of Alzheimer's disease. Adequate vitamin/mineral supplementation, especially B1, prior to conception and in the first trimester is recommended for mothers at risk for DS, especially older mothers and a gluten free diet for those with coeliac disease or gluten-gliadin sensitivity/intolerance. Hopefully this will prevent conception of a DS child, or prevent heart defects/stigmata if one is conceived. DS children should be investigated for the above and commence a food allergy free diet with relevant supplements to meet their needs as early as maximum development.

Adolescent↗
PubMed2006

How do heart disease and stroke become risk factors for Alzheimer's disease?

BACKGROUND: Heart disease and stroke are two of the major leading causes of death and disability in the world. Mainly affecting the elderly population, heart disease and stroke are important risk factors for Alzheimer's disease (AD). METHODS: This review examines the evidence linking chronic brain hypoperfusion (CBH) produced by several types of heart disease and stroke on the development of AD. RESULTS: The evidence indicates a strong association between such risk factors as coronary artery bypass surgery (CABG), atrial fibrillation, aortic/mitral valve damage, hypertension, hypotension, congestive heart failure, cerebrovascular-carotid atherosclerosis, and transient ischemic attacks in producing CBH. In people whose cerebral perfusion is already diminished by their advanced age, further cerebral blood flow reductions from heart-brain vascular-related risk factors, seemingly increases the probability of AD. The evidence also suggests that a neuronal energy crisis brought on by a relentless CBH is responsible for protein synthesis defects that later result in the classic AD neurodegenerative lesions such as the formation of excess beta-amyloid plaques and neurofibrillary tangles. CONCLUSIONS: Knowledge of how heart disease and stroke can progress to AD should provide a better understanding of the physiopathology characteristic of AD and also target more precise therapy in preventing, controlling or reversing this dementia.

Alzheimer Disease↗
PubMed2004

An experimental animal model of aseptic loosening of hip prostheses in sheep to study early biochemical changes at the interface membrane.

BACKGROUND: Aseptic loosening of hip prosthesis as it occurs in clinical cases in human patients was attributed to wear particles of the implants, the response of the tissue dominated by macrophages and the production of inflammatory mediators and matrix degrading enzymes; however, the cascade of events initiating the process and their interaction regarding the time course is still open and discussed controversially. Therefore, the goal of this study was to establish an experimental animal model in sheep allowing to follow the cascade of early mechanical and biochemical events within the interface membrane and study the sequence of how they contribute to the pathological bone resorption necessary for aseptic loosening of the implant. METHODS: A cemented modular system (Biomedtrix) was used as a hip replacement in 24 adult Swiss Alpine sheep, with one group receiving a complete cement mantle as controls (n = 12), and the other group a cement mantle with a standardized, lateral, primary defect in the cement mantle (n = 12). Animals were followed over time for 2 and 8.5 months (n = 6 each). After sacrifice, samples from the interface membranes were harvested from five different regions of the femur and joint capsule. Explant cell cultures were performed and supernatant of cultures were tested and assayed for nitric oxide, prostaglandin E2, caseinolytic and collagenolytic activity. RNA extraction and quantification were performed for inducible nitric oxide synthase, cyclooxygenase-2, interleukin 1, and interleukin 6. Overall differences between groups and time periods and interactions thereof were calculated using a factorial analysis of variance (ANOVA). RESULTS: The development of an interface membrane was noticed in both groups at both time points. However, in the controls the interface membrane regressed in thickness and biological activity, while both variables increased in the experimental group with the primary cement mantle defect over time. Nitric oxide (NO) and PGE2 concentrations were higher in the 8.5 months group (P < 0.0001) compared to the 2 months group with a tendency for the unstable group to have higher concentrations. The same was true for collagenolytic activity (P = 0.05), but not for caseinolytic activity that decreased over time (P < 0.0001). CONCLUSION: In this study, a primary cement mantle defect of the femoral shaft elicited biomechanical instability and biochemical changes over time in an experimental animal study in sheep, that resembled the changes described at the bone cement-interface in aseptic loosening of total hip prosthesis in humans. The early biochemical changes may well explain the pathologic bone resorption and formation of an interface membrane as is observed in clinical cases. This animal model may aid in future studies aiming at prevention of aseptic loosening of hip prosthesis and reflect some aspects of the pathogenesis involved.

Analysis of Variance↗
PubMed2005

Heart and soul/PRKCi and nagie oko/Mpp5 regulate myocardial coherence and remodeling during cardiac morphogenesis.

Organ morphogenesis requires cellular shape changes and tissue rearrangements that occur in a precisely timed manner. Here, we show that zebrafish heart and soul (Has)/protein kinase C iota (PRKCi) is required tissue-autonomously within the myocardium for normal heart morphogenesis and that this function depends on its catalytic activity. In addition, we demonstrate that nagie oko (Nok) is the functional homolog of mammalian protein associated with Lin-seven 1 (Pals1)/MAGUK p55 subfamily member 5 (Mpp5), and we dissect its earlier and later functions during myocardial morphogenesis. Has/PRKCi and Nok/Mpp5 are required early for the polarized epithelial organization and coherence of myocardial cells during heart cone formation. Zygotic nok/mpp5 mutants have later myocardial defects, including an incomplete heart tube elongation corresponding with a failure of myocardial cells to correctly expand in size. Furthermore, we show that nok/mpp5 acts within myocardial cells during heart tube elongation. Together, these results demonstrate that cardiac morphogenesis depends on the polarized organization and coherence of the myocardium, and that the expansion of myocardial cell size contributes to the transformation of the heart cone into an elongated tube.

Animals↗
PubMed1996

Mutations affecting the formation of the notochord in the zebrafish, Danio rerio.

In a large scale screen for mutants with defects in the embryonic development of the zebrafish we identified mutations in four genes,floating head (flh), momo (mom), no tail (ntl), and doc, that are required for early notochord formation. Mutations in flh and ntl have been described previously, while mom and doc are newly identified genes. Mutant mom embryos lack a notochord in the trunk, and trunk somites from the right and left side of the embryo fuse underneath the neural tube. In this respect mom appears similar to flh. In contrast, notochord precursor cells are present in both ntl and doc embryos. In order to gain a greater understanding of the phenotypes, we have analysed the expression of several axial mesoderm markers in mutant embryos of all four genes. In flh and mom, Ntl expression is normal in the germ ring and tailbud, while the expression of Ntl and other notochord markers in the axial mesodermal region is disrupted. Ntl expression is normal in doc embryos until early somitic stages, when there is a reduction in expression which is first seen in anterior regions of the embryo. This suggests a function for doc in the maintenance of ntl expression. Other notochord markers such as twist, sonic hedgehog and axial are not expressed in the axial mesoderm of ntl embryos, their expression parallels the expression of ntl in the axial mesoderm of mutant doc, flh and mom embryos, indicating that ntl is required for the expression of these markers. The role of doc in the expression of the notochord markers appears indirect via ntl. Floor plate formation is disrupted in most regions in flh and mom mutant embryos but is present in mutant ntl and doc embryos. In mutant embryos with strong ntl alleles the band of cells expressing floor plate markers is broadened. A similar broadening is also observed in the axial mesoderm underlying the floor plate of ntl embryos, suggesting a direct involvement of the notochord precursor cells in floor plate induction. Mutations in all of these four genes result in embryos lacking a horizontal myoseptum and muscle pioneer cells, both of which are thought to be induced by the notochord. These somite defects can be traced back to an impairment of the specification of the adaxial cells during early stages of development. Transplantation of wild-type cells into mutant doc embryos reveals that wild-type notochord cells are sufficient to induce horizontal myoseptum formation in the flanking mutant tissue. Thus doc, like flh and ntl, acts cell autonomously in the notochord. In addition to the four mutants with defects in early notochord formation, we have isolated 84 mutants, defining at least 15 genes, with defects in later stages of notochord development. These are listed in an appendix to this study.

Animals↗
PubMed1999

Mutations affecting tail and notochord development in the ascidian Ciona savignyi.

Ascidians are among the most distant chordate relatives of the vertebrates. However, ascidians share many features with vertebrates including a notochord and hollow dorsal nerve cord. A screen for N-ethyl-N-nitrosourea (ENU)-induced mutations affecting early development in the ascidian Ciona savignyi resulted in the isolation of a number of mutants including the complementing notochord mutants chongmague and chobi. In chongmague embryos the notochord fails to develop, and the notochord cells instead adopt a mesenchyme-like fate. The failure of notochord development in chongmague embryos results in a severe truncation of tail, although development of the tail muscles and caudal nerve tracts appears largely normal. Chobi embryos also have a truncation of the tail stemming from a disruption of the notochord. However, in chobi embryos the early development of the notochord appears normal and defects occur later as the notochord attempts to extend and direct elongation of the tail. We find in chobi tailbud embryos that the notochord is often bent, with cells clumped together, rather than extended as a column. These results provide new information on the function and development of the ascidian notochord. In addition, the results demonstrate how the unique features of ascidians can be used in genetic analysis of morphogenesis.

Animals↗
PubMed2005

The meiotic spindle of the Drosophila oocyte: the role of centrosomin and the central aster.

We provide here the first evidence that a distinct midzone is present in the Drosophila melanogaster female meiosis I spindle. This region has the ability to bind the Pavarotti kinesin-like (PAV-KLP) and Abnormal spindle (Asp) proteins, indicating a correct organization of the central spindle microtubules. We also identified the core component centrosomal protein centrosomin (CNN) at an unexpected site within the anaphase I spindle, indicating a role for CNN during the biogenesis of the female meiotic apparatus. However, there are no apparent defects in the midzone organization of cnn oocytes, whereas defects occur later when the central aster forms. The primary mutant phenotype of cnn oocytes is the failure to form a developed central microtubule organizing center (MTOC), although twin meiosis II spindles usually do form. Thus the central MTOC may not be essential for the formation of the inner poles of twin meiosis II spindles, as generally proposed, but it might be involved in maintaining their proper spacing. We discuss the proposal that, in the presence of a central MTOC, a chromatin-driven mechanism of spindle assembly like that described during meiosis I may control the morphogenesis of the twin meiosis II spindles.

Animals↗
PubMed2006

Brassinosteroid signals control expression of the AXR3/IAA17 gene in the cross-talk point with auxin in root development.

Transgenic plants overexpressing AXR3/IAA17 were impaired in root growth. Specifically, they exhibited severe defects in lateral root and root hair development similar to the root phenotypes of epi-brassinolide (epiBL)-treated wild-type plants. Here, we investigated the involvement of AXR3/IAA17 gene expression in brassinosteroid (BR)-regulated root development. Exogenous epiBL application significantly induced expression of the AXR3/IAA17 gene as well as several Aux/IAA genes, such as AXR2/IAA7, SLR/IAA14, and IAA28. We analyzed the transcription levels of several Aux/IAA genes related to root development in the BR signaling mutant bri1 and the BR biosynthesis mutant det2. AXR3/IAA17 gene expression was significantly decreased in bri1 plants. In det2 plants, expression of AXR3/IAA17 slightly decreased. This in turn suggests that epiBL induced these Aux/IAA genes, and that these induced gene products might function as factors in root development. Furthermore, AXR3/IAA17 might be involved in the BR signaling pathway, suggesting an intersection node of BR-auxin signaling in root development.

Arabidopsis↗
PubMed2005

Generating fringe-free images from phase-shifted interferometry data.

Weighted averaging of a sequence of phase-shifted interference patterns yields a fringe-free intensity image that can be useful for machine vision, lateral metrology, defect detection, and other supplementary tasks in a surface-profiling interferometer. Coefficients for effective fringe-removal algorithms follow from a Fourier analysis of phase-shifting errors. Theoretical and experimental examples illustrate the substantially improved performance of a well-designed weighted average over a simple linear sum of data frames.

Journal Article↗
PubMed2004

Successful ovariectomy in a dog with Glanzmann thrombasthenia.

Ovariectomy was performed in a 7-month-old Great Pyrenees with a severe congenital bleeding disorder. A diagnosis of Glanzmann thrombasthenia, a rare, congenital bleeding disorder characterized by a functional platelet defect, was later confirmed by isolation of genomic DNA from blood and amplification of exon 13 and intron 13 of the gene encoding for platelet glycoprotein subunit alphaIIb. Perioperative management consisted of administration of platelet-rich plasma prior to surgery and the use of high-frequency electrocoagulation to minimize tissue trauma. In addition, ovariectomy, rather than ovariohysterectomy, was performed to minimize surgical exposure required and manipulation of the urogenital tract. Results in this dog suggest that a combination of preoperative transfusion with functional platelets and use of techniques to minimize tissue trauma may allow abdominal surgery to be performed successfully in dogs with functional platelet disorders.

Animals↗
PubMed2000

Hernia uterus inguinale in a 46,XX female. A case report.

BACKGROUND: Hernia uterus inguinale, a rare congenital anomaly, is usually found in hermophrodites. CASE: A case of lateral fusion defect associated with müllerian duct development in a young woman with primary amenorrhea and normal karyotype occurred. In our patient, bilateral müllerian duct systems were rudimentary and failed to fuse in the midline. The left horn of the uterus and ipsilateral ovary lay in the left inguinal canal. The right horn of the uterus, along with the tube and ovary, was intraabdominal. CONCLUSION: In the operative management of this rare anomaly, care must be taken to preserve and reposition the ovary in the abdominal cavity.

Adult↗
PubMed2000

Progression of meiotic DNA replication is modulated by interchromosomal interaction proteins, negatively by Spo11p and positively by Rec8p.

Spo11p is a key mediator of interhomolog interactions during meiosis. Deletion of the SPO11 gene decreases the length of S phase by approximately 25%. Rec8p is a key coordinator of meiotic interhomolog and intersister interactions. Deletion of the REC8 gene increases S-phase length, by approximately 10% in wild-type and approximately 30% in a spo11Delta background. Thus, the progression of DNA replication is modulated by interchromosomal interaction proteins. The spo11-Y135F DSB (double strand break) catalysis-defective mutant is normal for S-phase modulation and DSB-independent homolog pairing but is defective for later events, formation of DSBs, and synaptonemal complexes. Thus, earlier and later functions of Spo11 are defined. We propose that meiotic S-phase progression is linked directly to development of specific chromosomal features required for meiotic interhomolog interactions and that this feedback process is built upon a more fundamental mechanism, common to all cell types, by which S-phase progression is coupled to development of nascent intersister connections and/or related aspects of chromosome morphogenesis. Roles for Rec8 and/or Spo11 in progression through other stages of meiosis are also revealed.

Chromosomes, Fungal↗
PubMedDate not supplied

Gastric volvulus in childhood.

Gastric volvulus is an uncommon condition more so in the paediatric age group. The cause of gastric volvulus may be idiopathic or secondary to various congenital or acquired conditions. In this short series of three patients, one had volvulus which was due to ligamentous laxity and mobile spleen, second had congenital postero-lateral diaphragmatic defect and the third had hiatus hernia.

Child↗
PubMed2000

Of mice and men: dissecting the genetic pathway that controls left-right asymmetry in mice and humans.

The increasing ability to manipulate the mouse genetically has created a model system that is both accessible and an accurate mirror of human development. A combination of analysis of existing spontaneous mouse mutations and creation of targeted mutations has identified at least z24 genes involved in the specification of mouse left-right asymmetry. These genes function in a carefully orchestrated manner first to create asymmetry at the node, then to signal it to the immediately surrounding cells via the node monocilia, and finally to amplify the initial asymmetry and propagate it to the developing organs. Defects at different steps in this pathway result in differences in the final phenotype. Human homologues exist for most of the mouse left-right determining genes. Notably, when human mutations in these genes have been identified in patients with defects of laterality determination, the human phenotype correlates very closely with the corresponding mouse phenotype.

Abnormalities, Multiple↗
PubMed2001

[Tympanoplasty for patients with destruction of the stapes].

Mode of tympanoplasty allowing reconstruction of the drum and erosioned malleus handle is described. For this purpose an autoossicle fragment of the lengthened shape was inserted into the blind channel created in fascia transplant which "dressed" on the handle's remnant for the osseous fragment and remnants of the handle to appear in one fascia channel. This method was applied in 11 patients with subtotal drum perforation and erosion of the hammer's handle. In 9 of them 0.5-2 years later the defect of the drum fully disappeared. In 7 patients the handle resumed normal length while the drum became conic. The average pure air conduction threshold in frequencies 0.5-2 kHz has become 25.5 +/- 3.5 dB (before the operation 38.2 +/- 2.3 dB; p > 0.01), the average bone conduction threshold 14.3 +/- 2.6 dB (before operation 13.9 +/- 2.4 dB; p < 0.05).

Ear Ossicles↗
PubMed2002

Uterus didelphys with cervical agenesis associated with adenomyosis, a leiomyoma and ovarian endometriosis. A case report.

BACKGROUND: Elevated level of serum CA-125 was detected in a 48-year-old woman who was diagnosed with a lateral fusion defect in association with congenital agenesis of the uterine cervix. This unusual case combined two developmental anomalies of the müllerian duct. CASE REPORT: A 48-year-old woman consulted our outpatient department due to persistent abdominal pain for six months. Bimanual pelvic examination showed absence of the cervix, an anteverted uterus and a 6-cm, left adnexal mass. Ultrasound and computed tomography revealed a uterus didelphys with a 3-cm cystic mass over the right ovary. Serum level of CA-125 was 641.4 U/mL. The patient underwent exploratory laparotomy, and total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. Pathology confirmed adenomyosis and a leiomyoma of the uterus with functional endometrium in conjunction with endometriosis of the right ovary. CONCLUSION: Multiple müllerian anomalies associated with adenomyosis and endometriosis should be considered in patients presenting with primary amenorrhea. Thorough evaluation, careful planning, fertility preservation and postoperative outcomes should be reviewed.

Abdominal Pain↗