Jun
04
2009
0

Continuous fetal heart rate monitoring in patients with preterm premature rupture of membranes undergoing expectant management.

Objective. Continuous fetal heart rate (FHR) monitoring is considered by some as necessary to the expectant management of patients with preterm premature rupture of membranes (PPROM). No data exist to support this premise, and liability may be incurred if such an order cannot be practically carried out. The purpose of our study is to evaluate the performance of prolonged FHR monitoring in terms of the completeness of recorded tracings. Methods. A retrospective cohort study was performed between 2004 and 2006 in a tertiary care hospital on patients being expectantly managed with PPROM at 24-34 weeks of gestation. Forty-seven singleton gravidas with a physician order of continuous external FHR monitoring were included. Exclusion criteria were evidence of labour, chorioamnionitis or FHR abnormalities that prompted delivery. FHR tracings during the prolonged monitoring period were reviewed. Results. The study cohort was monitored for a duration of 321-2272 min (mean 970 min). In total, 28.3% (95% confidence interval 23.8-33%) of the tracing did not show a legible recording. Gestational age is negatively correlated with the proportion of absent tracing, whereas body mass index is positively correlated. There is no significant difference in the absent signal proportion between the first half of the monitoring period and the second half or between day and night. Conclusions. In patients with PPROM being expectantly managed, a significant proportion (28.3%) of the FHR tracing was not recorded as ordered. This suggests that ‘continuous’ prolonged external fetal monitoring may not be practically feasible and alternative monitoring approaches should be considered.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

CADASIL and ALS: A link?

We report the case of a 66-year-old female who presented with dysarthria and dysphonia. Brain MRI abnormalities showed confluent white matter lesions and subcortical lacunar infarcts, suggesting cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL),confirmed by the presence of a heterozygous mutation in the Notch3 gene. Clinical signs and course were consistent with amyotrophic lateral sclerosis (ALS) as was the electromyographic pattern. The possible pathogenic role for a mutation in the Notch3 gene is discussed considering recent data on hypoxia in the pathophysiology of ALS.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Sensory Impairments and Autism: A Re-Examination of Causal Modelling.

Sensory impairments are widely reported in autism, but remain largely unexplained by existing models. This article examines Kanner’s causal reasoning and identifies unsupported assumptions implicit in later empirical work. Our analysis supports a heterogeneous causal model for autistic characteristics. We propose that the development of a standardised framework for analysing autistic characteristics would facilitate the identification of sub-groups and the location of biological markers for genetic variation. We also support a neuroconstructivist model proposing that peripheral sensory abnormalities disrupt compilation of complex skills; impact on synaptogenesis, synaptic pruning and myelination; and subsequently manifest themselves as autistic behaviours. This model explains some of the structural and functional brain abnormalities and many of the perceptual, cognitive and attentional features found in autism.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Echocardiographic findings in patients with sickle cell disease.

Pulmonary hypertension is a complication of sickle cell disease that is associated with increased mortality. Whether this complication is associated with hemolysis has been questioned. Systolic pulmonary artery blood pressure can be estimated from echocardiography-determined tricuspid regurgitation velocity (TRV). A velocity of 2.5 m/s or higher suggests possible pulmonary hypertension. A retrospective review of hospital records from adult patients with sickle cell disease undergoing echocardiography in 2006 and 2007 was performed at a tertiary level hospital. Echocardiographic, demographic, and clinical laboratory data were collected. Echocardiographic results were available for 105 adult sickle cell patients. Of these, 62 (59%) had a TRV >/=2.5 m/s and 24 (22.8%) had a TRV >/=3.0 m/s. Mitral valve regurgitation was observed in 44% and left ventricular abnormalities (defined by either hypertrophy or dilation) in 28% of cases. Elevated TRV had independent and significant associations with greater age, higher serum lactate dehydrogenase (LDH) concentration, and lower hemoglobin concentration. We confirmed that elevated TRV is common among hospital-based adults with sickle cell disease. Significant, independent associations were found with both elevated LDH concentration and degree of anemia, suggesting that hemolytic and other mechanisms contribute to pulmonary hypertension in patients with sickle cell disease.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Nerve conduction studies in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary cerebral microangiopathy linked to mutations in the Notch3 gene. The cerebral impairments of CADASIL are well-known, but peripheral nervous impairments such as polyneuropathy are less clear. Recently, peripheral neuropathy was proposed as one of the CADASIL phenotypes. We investigated peripheral nerve involvement in CADASIL patients. Forty-three CADASIL patients with confirmed Notch3 gene mutations underwent a nerve conduction studies using a conventional surface technique in 86 upper and lower extremities. Nerve conduction abnormalities were apparent in seven of the 43 patients. Of the seven patients, four displayed nerve entrapment syndromes (carpal tunnel syndrome, n = 3; ulnar neuropathy, n = 1), and three displayed sensorimotor polyneuropathy. Of the latter three, two patients had diabetes mellitus. We suggest that peripheral neuropathy may not be part of the CASASIL phenotype. However, genotype-phenotype heterogeneity can not be excluded.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Lambs infected with UV-attenuated sporocysts of Sarcocystis ovicanis produced abnormal sarcocysts and induced protective immunity against a challenge infection.

The present study surveyed the prevalence of natural infection of the sheep esophagus muscle with sarcocysts of Sarcocystis ovicanis and examined induction of protective immunity using UV-attenuated sporocysts. The overall prevalence of natural infection of the sheep was 95%. Infectivity of the collected sarcocysts was confirmed by shedding of sporulated oocysts after feeding infected esophageal tissues to dogs. To induce protective immunity, lambs were immunized 3 times (once a week) with 1.5 x 10(4) sporocysts exposed to UV-light for 30 min (UV-30 group) or 60 (UV-60 group) min and then challenged with 1.5 x 10(4) normal sporocysts at the 3rd week post the 1st vaccination. These lambs showed high survival and less clinical signs of sarcocystosis than normal infected lambs. The attenuated sporocysts produced abnormal cysts; small in size and detached from the muscle fiber. These abnormalities were more obvious in UV-60 group than UV-30 group. Also, the IFN-gamma level and lymphocyte percentage were increased while the total leukocyte count was decreased in the UV-60 group compared with other groups. The high level of IFN-gamma may be an evidence for the induction of Th1 responses which may have protective effect against a challenge infection.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Intravascular lymphomatosis of the brain in a patient with myelodysplastic syndrome.

BACKGROUND: A 77-year-old retired research pharmacologist with a long-standing history of anemia and a recent pathologically confirmed diagnosis of myelodysplastic syndrome was referred to a stroke unit for evaluation of slowly progressive cognitive deterioration, confusion and paroxysmal stroke-like episodes. A previous neurological work-up had revealed no noteworthy abnormalities except for chronic bilateral caudate infarctions seen on MRI and CT examinations of the brain. INVESTIGATIONS: Physical examination, laboratory testing, brain MRI scanning, EEG, transesophageal echocardiography, cerebral angiography, CT scanning, and brain biopsy. DIAGNOSIS: Intravascular lymphomatosis of the brain. MANAGEMENT: Combined chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) and rituximab.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Lens transplantation in zebrafish and its application in the analysis of eye mutants.

The lens plays an important role in the development of the optic cup([1,2]). Using the zebrafish as a model organism, questions regarding lens development can be addressed. The zebrafish is useful for genetic studies due to several advantageous characteristics, including small size, high fecundity, short lifecycle, and ease of care. Lens development occurs rapidly in zebrafish. By 72 hpf, the zebrafish lens is functionally mature ([3]). Abundant genetic and molecular resources are available to support research in zebrafish. In addition, the similarity of the zebrafish eye to those of other vertebrates provides basis for its use as an excellent animal model of human defects([4-7]). Several zebrafish mutants exhibit lens abnormalities, including high levels of cell death, which in some cases leads to a complete degeneration of lens tissues ([8]). To determine whether lens abnormalities are due to intrinsic causes or to defective interactions with the surrounding tissues, transplantation of a mutant lens into a wild-type eye is performed. Using fire-polished metal needles, mutant or wild-type lenses are carefully dissected from the donor animal, and transferred into the host. To distinguish wild-type and mutant tissues, a transgenic line is used as the donor. This line expresses membrane-bound GFP in all tissues, including the lens. This transplantation technique is an essential tool in the studies of zebrafish lens mutants.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Narrative review: the emerging clinical implications of the role of aldosterone in the metabolic syndrome and resistant hypertension.

The prevalence of obesity, diabetes, hypertension, and cardiovascular and chronic kidney disease is increasing in developed countries. Obesity, insulin resistance, and hypertension commonly cluster with other risk factors for cardiovascular and chronic kidney disease to form the metabolic syndrome. Emerging evidence supports a paradigm shift in our understanding of the renin-angiotensin-aldosterone system and in aldosterone’s ability to promote insulin resistance and participate in the pathogenesis of the metabolic syndrome and resistant hypertension. Recent data suggest that excess circulating aldosterone promotes the development of both disorders by impairing insulin metabolic signaling and endothelial function, which in turn leads to insulin resistance and cardiovascular and renal structural and functional abnormalities. Indeed, hyperaldosteronism is associated with impaired pancreatic beta-cell function, skeletal muscle insulin sensitivity, and elevated production of proinflammatory adipokines from adipose tissue, which results in systemic inflammation and impaired glucose tolerance. Accumulating evidence indicates that the cardiovascular and renal abnormalities associated with insulin resistance are mediated in part by aldosterone acting on the mineralocorticoid receptor. Although we have known that mineralocorticoid receptor blockade attenuates cardiovascular and renal injury, only recently have we learned that mineralocorticoid receptor blockade improves pancreatic insulin release, insulin-mediated glucose utilization, and endothelium-dependent vasorelaxation. In summary, aldosterone excess has detrimental metabolic effects that contribute to the metabolic syndrome and endothelial dysfunction, which in turn contribute to the development of resistant hypertension as well as cardiovascular disease and chronic kidney disease.

Written by admin in: Ischemic Brain Damage |
Jun
04
2009
0

Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest.

BACKGROUND: Hypoxic ischemic brain injury secondary to pediatric cardiac arrest (CA) may result in acute symptomatic seizures. A high proportion of seizures may be nonconvulsive, so accurate diagnosis requires continuous EEG monitoring. We aimed to determine the safety and feasibility of long-term EEG monitoring, to describe electroencephalographic background and seizure characteristics, and to identify background features predictive of seizures in children undergoing therapeutic hypothermia (TH) after CA. METHODS: Nineteen children underwent TH after CA. Continuous EEG monitoring was performed during hypothermia (24 hours), rewarming (12-24 hours), and then an additional 24 hours of normothermia. The tolerability of these prolonged studies and the EEG background classification and seizure characteristics were described in a standardized manner. RESULTS: No complications of EEG monitoring were reported or observed. Electrographic seizures occurred in 47% (9/19), and 32% (6/19) developed status epilepticus. Seizures were nonconvulsive in 67% (6/9) and electrographically generalized in 78% (7/9). Seizures commenced during the late hypothermic or rewarming periods (8/9). Factors predictive of electrographic seizures were burst suppression or excessively discontinuous EEG background patterns, interictal epileptiform discharges, or an absence of the expected pharmacologically induced beta activity. Background features evolved over time. Patients with slowing and attenuation tended to improve, whereas those with burst suppression tended to worsen. CONCLUSIONS: EEG monitoring in children undergoing therapeutic hypothermia after cardiac arrest is safe and feasible. Electrographic seizures and status epilepticus are common in this setting but are often not detectable by clinical observation alone. The EEG background often evolves over time, with milder abnormalities improving and more severe abnormalities worsening.

Written by admin in: Ischemic Brain Damage |

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