Rett syndrome: a disorder affecting early brain growth.
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Brain↗
Biomedical subjects
S Naidu
Publications and source records attributed to S Naidu.
Efficacy of phenytoin in eclampsia.
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Adolescent↗
Glutaraldehyde-tanned bovine carotid artery graft for infrainguinal vascular reconstruction: 5-year follow-up.
OBJECTIVE: To assess the long-term patency of a modified biological conduit, the glutaraldehyde-tanned bovine carotid artery, in above-knee infrainguinal arterial reconstruction. PATIENTS AND METHODS: Prospective follow-up of a cohort of 58 above-knee femoropopliteal grafts in 55 patients. Graft patency was assessed at yearly intervals with doppler ankle pressure measurements. RESULTS: The median follow-up period has been 67 months. Nine grafts occluded within 30 days of surgery and a further 19 graft closures have been observed in the follow-up period. The overall cumulative primary graft patency at 1, 3 and 5 years was 70%, 61% and 56%, respectively. If the 30-day graft failures are excluded, the primary graft patency rises to 83%, 74% and 68% at 1, 3 and 5 years, respectively. Six limbs have been amputated, four above the knee and two below the knee. There were no graft aneurysms and no graft infections. CONCLUSION: Results indicate that the modified bovine carotid artery graft with an above-knee anastomosis does not seem to be inferior to PTFE, but is inferior to reversed vein. Modified biological conduits offer a reasonable alternative to synthetic grafts for infrainguinal arterial reconstruction and appear to maintain acceptable long-term mechanical stability.
Aged↗
A male child with the rumpshaker mutation, X-linked spastic paraplegia/Pelizaeus-Merzbacher disease and lysinuria.
A 3.5-year-old boy had intact cognition, delayed walking, progressive spastic paraparesis and congenital nystagmus. The mother denied family history of any neurological disorders, so an extensive work-up was begun. Lysinuria, increased signal on cerebral T2-weighted MRI imaging and the rumpshaker mutation (Ile186Thr) in his proteolipid protein gene. PLP, were found. When faced with these facts, the mother admitted that she was related to the family reported by Johnston and McKusick in 1962 and Kobayashi in 1994, in whom this mutation has been reported. This is the first report of an abnormal MRI scan in this family.
Brain↗
Thromboelastography in abruptio placentae.
The purpose of this study was to document thromboelastographic (TEG) changes in abruptio placentae and to compare these results with that of conventional tests used to monitor coagulation. This was a prospective study of 30 patients with abruptio placentae. All coagulation investigations including the TEG were performed on admission, immediately following delivery, and after periods of 4 hours and 24 hours. Results showed that standard coagulation tests detected coagulation abnormalities except the platelet count returned to normal limits within 24 hours of delivery. There was strong correlation between fibrinogen levels and the TEG parameters, ma and k time (r=0.8). There was moderate correlation between platelet count and ma (r=0.6). In conclusion, minor abnormalities in the clotting profile are clinically unimportant. The TEG does not detect such minor abnormalities because of its inherent ability to test the coagulation cascade as a whole. Major abnormalities are clinically relevant and the TEG detect 75% of them. Further, the TEG establishes the diagnosis of hypercoagulability an early sign of disseminated intravascular coagulation. Although standard laboratory tests are still necessary to detect coagulation abnormalities on admission, the TEG is a useful test in large obstetric units where laboratory results are not immediately available for the purposes of monitoring and treating ongoing coagulation defects.
Journal Article↗
The efficacy of phenytoin in eclampsia.
Although the Eclampsia Trial Collaborative Group reported that magnesium sulphate was more effective in preventing recurrent convulsions in eclampsia than phenytoin, confirmatory evidence that phenytoin is not useful as a prophylactic anticonvulsant agent in eclampsia is necessary. This prospective descriptive study enrolled 68 women with eclampsia. Recurrence of seizures occurred in 18 (26.5%) patients following phenytoin therapy. In 16 patients, the seizure recurrence occurred between the loading dose and first maintenance dose at 6 hours. There was no statistical difference in the clinical characteristics of those who had seizure recurrence compared with those that did not. Seizure recurrence following phenytoin therapy in eclampsia is unacceptably high. These results suggest that phenytoin is not effective as a prophylactic anticonvulsant in eclampsia. No conclusions about its effectiveness compared with alternative prophylactic anticonvulsants can be made from this descriptive study.
Journal Article↗
Mesenteric revascularisation for acute-on-chronic intestinal ischaemia.
Eleven patients (eight women) underwent urgent revascularisation for acute-on-chronic mesenteric ischaemia. Four patients had dual vessel and seven single vessel reconstructions. Two patients underwent simultaneous bowel resection and one patient has had three separate grafts to the superior mesenteric artery. There were two peri-operative deaths and three have died in the late follow-up period after 18, 24 and 36 months. The remainder have survived for between five and 63 months. Revascularisation for acute-on-chronic mesenteric ischaemia has been shown to be technically possible and of substantial benefit to patients who would otherwise be treated as terminal cases.
Acute Disease↗
Assessment of adrenal function in women heterozygous for adrenoleukodystrophy.
Adrenoleukodystrophy (ALD) is an X-linked recessive disorder that destroys the white matter of the brain and is associated with adrenal insufficiency. The prevalence of adrenal dysfunction in 71 women carriers of the X-linked ALD gene was studied. These subjects were identified initially on the basis of being obligate carriers of the X-linked trait by pedigree analysis and were confirmed by plasma very long chain fatty acid levels consistent with a heterozygote status. One subject had well documented overt adrenal insufficiency, diagnosed and treated since age 9 yr. Among the remaining women, the mean serum 0800 h and 1 h post-ACTH cortisol concentrations [16 +/- 7 (+/-SD) and 34 +/- 8 micrograms/dL, respectively] were normal. All subjects had normal ACTH-stimulated serum cortisol levels, i.e. more than 20 micrograms/dL. However, 4 subjects (6%) had subnormal ACTH-stimulated aldosterone concentrations (mean, 9 +/- 6 vs. 42 +/- 16 ng/dL for other subjects; P = 0.001, by Mann Whitney rank sum test). Three of these women (75%) were taking nonsteroidal antiinflammatory agents (NSAIDs), whereas only 4 of 67 (6%) subjects with normal aldosterone responsiveness were NSAIDs users (P < 0.01, by Fisher's exact test). Thus, NSAIDs use was associated with increased risk of hypoaldosteronism (odds ratio, 50.2; 95% confidence interval, 3.3-266; P < 0.002). Three of these four women had symptoms consistent with mineralocorticoid deficiency. Serum sodium and potassium concentrations were normal in all subjects. Basal and metyrapone-stimulated plasma ACTH concentrations were also normal in adequately tested subjects with and without mineralocorticoid insufficiency. Five of eight subjects (63%) who underwent testing with synthetic ovine CRH (oCRH) had abnormalities. Three did not meet the criteria for adequate cortisol stimulation (i.e. > 20 micrograms/dL) and had peak ACTH levels greater than 30 pg/mL. Two other subjects had exaggerated ACTH responses with normal cortisol levels. There were no significant differences in the mean or median levels of very long chain fatty acid, C26:0, C24/22 ratios, or C26/22 ratios among the entire subject group, the subgroup with blunted aldosterone responses to ACTH, and the subgroup with blunted responses to oCRH (P > 0.05, by ANOVA and Kruskall-Wallis test for C26, C24/22 ratio, and C26/22 ratio). We conclude that 1) adrenal cortical insufficiency rarely develops in ALD heterozygotes; 2) isolated mineralocorticoid insufficiency can occur in ALD heterozygotes, as has been previously reported to occur with autoimmune and acquired immunodeficiency syndrome-related adrenal dysfunction; 3) ALD heterozygosity may predispose these individuals to NSAID-related hypoaldosteronism; and 4) a subclinical decrease in glucocorticoid reserve, as measured by oCRH testing, may be present in a majority of these women. Aldosterone levels should be included in the ACTH stimulation testing when seeking evidence of adrenal insufficiency in affected women. NSAIDs should be considered a risk factor for the development of hypoaldosteronism in women heterozygous for ALD.
Adolescent↗
Neuroanatomy in Rett syndrome: cerebral cortex and posterior fossa.
Rett syndrome (RS), a neurodevelopmental disorder of unknown etiology occurring almost exclusively in females, is characterized by autistic-like behavior, motor dysfunction, loss of language skills, dementia, and microcephaly. This study is a follow-up and extension of a previously reported neuroimaging study of patients with RS. We replicated previously reported findings with a larger patient population, and the volumetric MRI analysis was extended to include an analysis of neuroanatomy of the posterior fossa. Twenty girls with RS were compared with individually age- and gender-matched normal controls. Patients with RS showed global reduction in gray- and white-matter volumes. The prefrontal, posterior-frontal, and anterior-temporal regions showed the largest bilateral decrease in gray-matter volume, whereas white-matter volume was uniformly reduced throughout the brain. We found confirmation for the preferential reduction in caudate nucleus volume. However, we observed no preferential reduction in midbrain volume despite a preferential reduction in the midsagittal area of this region. We also present an individual case comparison between monozygotic twins discordant for RS.
Adolescent↗
Differing religious views on the AIDS epidemic.
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Acquired Immunodeficiency Syndrome↗
The radiological appearance of atherosclerotic popliteal artery aneurysms: the "dog-leg" sign.
The radiological appearance of popliteal aneurysms is described. Althought the lumen of the artery is often of normal diameter there is elongation of the vessel which frequently results in an acute "dog-leg". This sign has not been previously described.
Aneurysm↗
Rett syndrome: natural history and underlying disease mechanisms.
Rett syndrome (RS) is a neurological disorder that mainly, and possibly exclusively, affects girls. Diagnosis continues to be based upon a consistent constellation of clinical features observed in all of the patients worldwide. A biological marker has not been identified. In spite of this serious limitation, it is generally agreed that RS is a distinct entity and that it is genetically determined. Although it is associated with loss of function between infancy and the fifth year of life, its course becomes relatively static thereafter, setting it apart from most of the genetic neurodegenerative disorders of childhood. Neuropathological and neurochemical studies call attention to RS as a neurodevelopmental disorder of infancy resulting in failed brain growth. Clarification of its pathogenesis may provide new insight into normal brain development.
Adolescent↗
Abnormalities in neuronal maturation in Rett syndrome neocortex: preliminary molecular correlates.
In correspondence with the severe cognitive impairment and autistic features of Rett syndrome (RS), multiple anomalies of the cerebral cortex that include generalized reductions in dendritic arborizations and in cholinergic markers have been found. Considering the potential role of neurotransmitters in cortical differentiation, we have studied the relationship between cholinergic deficit and dendritic protein expression in RS and in a relevant animal model. Dendritic development is characterized by the sequential expression of cytoskeletal proteins whose levels remain relatively stable in adult life. Using quantitative immunoblotting, we have determined that in RS there is a reduction in proteins linked to early dendritic development [microtubule-associated protein (MAP)-5, MAP-2]. By contrast, in Down syndrome there is relative generalized increase in dendritic proteins. Mice with basal forebrain lesions at birth, which transiently decrease cholinergic innervation to the cortex, showed in adulthood reductions in MAP-2 that resemble those seen in RS. We conclude that dendritic anomalies in RS represent disturbances in early cortical differentiation and that cholinergic deficit may play a critical role in their pathogenesis as suggested by the animal data.
Adolescent↗
Dopamine transporters are markedly reduced in Lesch-Nyhan disease in vivo.
Dopamine (DA) deficiency has been implicated in Lesch-Nyhan disease (LND), a genetic disorder that is characterized by hyperuricemia, choreoathetosis, dystonia, and compulsive self-injury. To establish that DA deficiency is present in LND, the ligand WIN-35,428, which binds to DA transporters, was used to estimate the density of DA-containing neurons in the caudate and putamen of six patients with classic LND. Comparisons were made with 10 control subjects and 3 patients with Rett syndrome. Three methods were used to quantify the binding of the DA transporter so that its density could be estimated by a single dynamic positron emission tomography study. These approaches included the caudate- or putamen-to-cerebellum ratio of ligand at 80-90 min postinjection, kinetic analysis of the binding potential [Bmax/(Kd x Vd)] using the assumption of equal partition coefficients in the striatum and the cerebellum, and graphical analysis of the binding potential. Depending on the method of analysis, a 50-63% reduction of the binding to DA transporters in the caudate, and a 64-75% reduction in the putamen of the LND patients was observed compared to the normal control group. When LND patients were compared to Rett syndrome patients, similar reductions were found in the caudate (53-61%) and putamen (67-72%) in LND patients. Transporter binding in Rett syndrome patients was not significantly different from the normal controls. Finally, volumetric magnetic resonance imaging studies detected a 30% reduction in the caudate volume of LND patients. To ensure that a reduction in the caudate volume would not confound the results, a rigorous partial volume correction of the caudate time activity curve was performed. This correction resulted in an even greater decrease in the caudate-cerebellar ratio in LND patients when contrasted to controls. To our knowledge, these findings provide the first in vivo documentation of a dopaminergic reduction in LND and illustrate the role of positron emission tomography imaging in investigating neurodevelopmental disorders.
Adolescent↗
Neuronal migration abnormality in peroxisomal bifunctional enzyme defect.
Patterns of brain dysgenesis that resemble those in the Zellweger syndrome were demonstrated in a boy with an isolated defect of the peroxisomal bifunctional enzyme. There was bilateral centrosylvian pachygyria and polymicrogyria, diffuse hemispheric hypomyelination with heterotopic neurons, Purkinje cell heterotopias, and simplified convolutions of the dentate nucleus and inferior olive. This association of Zellweger syndrome-like brain dysgenesis with a defect of a single peroxisomal enzyme provides new opportunities for the study of pathogenetic mechanisms in peroxisomal disorders.
3-Hydroxyacyl CoA Dehydrogenases↗
Cognitive and brain magnetic resonance imaging findings in adrenomyeloneuropathy.
Neuropsychological functioning and brain magnetic resonance imaging (MRI) were evaluated in 84 men with adrenomyeloneuropathy (AMN). MRI was normal in 61%, the "pure AMN" group, while 39%, the "cerebral AMN" group, showed brain white matter abnormalities. Except for mild deficits in psychomotor speed and visual memory, neuropsychological function was normal in pure AMN. Most patients with cerebral AMN had normal IQ and language but evidenced impaired psychomotor speed, spatial cognition, memory, and executive functions. Patients with MRI evidence of very severe cerebral disease had global and language impairment as well, and deficits in all patients were highly correlated with degree of brain MRI involvement.
Adrenoleukodystrophy↗
Randomised study assessing the effect of phenytoin and magnesium sulphate on maternal cerebral circulation in eclampsia using transcranial Doppler ultrasound.
OBJECTIVE: To assess maternal middle cerebral artery flow velocity patterns as measured by transcranial Doppler ultrasound (TCD) in eclampsia and to investigate the effect of the anticonvulsants magnesium sulphate (MgSO4) and phenytoin on cerebral circulation. DESIGN: Prospective randomised study. SETTING: High care obstetric unit, King Edward VIII Hospital, Durban, South Africa. PARTICIPANTS: Twenty-four eclamptic patients: 13 received MgSO4 and 11 phenytoin. INTERVENTION: Middle cerebral artery flow velocity waveforms were measured using 2 MHz pulsed Doppler ultrasound via the transtemporal approach in eclamptic patients, before and 15 minutes after the loading dose of anticonvulsant. RESULTS: Magnesium sulphate significantly reduced the pulsatility index (P = 0.002) and mean flow velocity (P = 0.02) in the middle cerebral artery, whereas phenytoin failed to produce any statistically significant effect. However, differences between groups were not statistically significant. Systolic and diastolic blood pressures were reduced in both the MgSO4 and phenytoin groups. CONCLUSION: These findings provide firm evidence that MgSO4 relieves cerebral vasospasm, compared with phenytoin, and may therefore be the better drug for the prevention of eclamptic convulsion.
Adolescent↗
Nurses' perceptions of urinary catheter selection and management.
Nurses are often responsible for the initiation of catherization procedures for patients within the hospital or community setting. This nursing role requires contemporary information on catheter selection and problem solving in the maintenance of urinary catheters. A descriptive survey with a questionnaire sent to registered and enrolled nurses (N = 709) within an Australian metropolitan area health service was undertaken to determine their current knowledge level in relation to catheter care practices. Registered nurses represented 91% of the sample, with 66% of the entire sample having 7 or more years of nursing experience. Only 14% of nurses believed that their knowledge levels were adequate, with very few receiving postregistration education. Only 31% of the respondents recommended the use of purely silicone catheters, these being the least cytotoxic to the urethra for longterm use. Less than half of the respondents were unaware of the availability of female-length catheters. There was a general lack of knowledge of current catheter costs that would have major implications for unit budgets. The apparent gaps in nursing knowledge of catheter care suggest the need for urgent educational programs on catheter care practices for nurses within this service and the initiation of an area-wide standardized policy in catheter selection and management.
Attitude of Health Personnel↗