Biomedical subjects

G T Plant

Publications and source records attributed to G T Plant.

At least 55 records · Page 3Linked to original sources

PubMed2002

B Cell lymphoma of the brain stem masquerading as myasthenia.

A 54 year old man is described with signs compatible with ocular myasthenia gravis and an apparent excellent response to pyridostigmine. Subsequent clinical progression and further investigation suggested the presence of an inflammatory brain stem lesion, which responded to corticosteroid therapy. Clinical relapse, including the development of central neurogenic hyperventilation, led to a brain stem biopsy, confirming a diagnosis of B cell lymphoma. This case illustrates the propensity of primary CNS lymphoma (PCNSL) to mimic other conditions. Brain MRI is mandatory in presumed "test negative" ocular myasthenia with atypical clinical findings. Spontaneous regression of PCNSL or response to corticosteroids is common and should not mitigate against the diagnosis. Histopathological confirmation should ideally be made before starting therapy, as this may obscure or delay the correct diagnosis. Although PCNSL is rare, it must be considered in all patients with brain stem syndromes, and in all patients 50 years or older with contrast enhancing focal lesions.

Biopsy↗

PubMed2002

Ataxia in the setting of complicated enteropathy: double jeopardy.

The differential diagnosis of subacute onset ataxia in the setting of enteropathy is wide. A 54 year old patient with a pancerebellar syndrome and known ulcerative jejunoileitis is described. Small bowel biopsy showed evidence of enteropathy associated T cell lymphoma and subsequent neuropathological analysis and immunophenotyping confirmed metastasis of this tumour to the cerebellum. The presence of anti-gliadin antibodies and MRI evidence of a more longstanding process suggested additional immunologically mediated cerebellar dysfunction. Lymphomatous involvement of the CNS is rare in patients with complicated enteropathies, and has not been previously reported to involve the cerebellar parenchyma. This diagnostic possibility should be borne in mind before attributing cerebellar dysfunction in patients with the coeliac related enteropathies to nutritional compromise or immunological dysfunction (gluten ataxia) alone.

Ataxia↗

PubMed2002

Progressive ventricular enlargement in patients with clinically isolated syndromes is associated with the early development of multiple sclerosis.

BACKGROUND: In patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS), the extent of brain magnetic resonance imaging (MRI) lesion load influences the probability and time to development of clinically definite MS. Cerebral atrophy is recognised in established MS, but its time of onset and whether, in early disease, it is related to MRI lesion load or clinical outcome is less certain. OBJECTIVES: This study investigated ventricular enlargement over one year in CIS patients and explored its relation with lesion load and clinical outcome. METHODS: A semi-automated thresholding technique for measuring ventricular volume (MIDAS) was applied to MRI scans in a cohort of 55 patients with CIS, recruited consecutively and imaged within three months of the onset of symptoms and again after one year. RESULTS: Clinical MS had developed after one year in 16 of 40 patients with an abnormal baseline T2 scan and 2 of 15 with a normal scan. Significant ventricular enlargement was seen in 27 of 55 patients who fulfilled the new McDonald MRI criteria for MS using all available MRI at clinical follow up (median increase 0.3 cm(3), p=0.005) Significant increase in ventricular volume was also seen in the 18 of 55 patients who developed clinical MS over the follow up period (median increase 0.5 cm(3), p=0.006). There were significant but modest correlations between baseline lesion measures and subsequent ventricular enlargement. CONCLUSIONS: (1) Lesions and atrophy are both associated with early relapse leading to a diagnosis of clinical MS; (2) while lesions contribute to the development of atrophy, atrophy may also develop by other mechanisms. This suggests that MR measures have a complementary role in monitoring the course of MS, even from the earliest clinical stage.

Adolescent↗

PubMed2001

Asymmetrical activation of human visual cortex demonstrated by functional MRI with monocular stimulation.

We have demonstrated asymmetric activation patterns in the visual cortices of normal humans who have undergone functional MRI with monocular photic stimulation. The contralateral hemisphere is activated more strongly and to a greater spatial extent than the ipsilateral hemisphere when either eye is stimulated. This asymmetry can be explained by nasotemporal asymmetries which have been described in anatomical studies of the visual system in primates and humans. In part, the representation of the monocular crescent of the temporal hemifield of either eye, which exists only in the crossed projection, may explain this. In addition, within the binocular field, there is a biased crossed projection of nasal retinal ganglion cells which drive the contralateral ocular dominance columns in V1. Finally, the blind spot representation in the ipsilateral visual cortex may also contribute to the observed asymmetries. Our study may in effect provide a functional correlate of the anatomical asymmetries that have been observed in humans and animals.

Adult↗

PubMed2001

Detection of optic nerve atrophy following a single episode of unilateral optic neuritis by MRI using a fat-saturated short-echo fast FLAIR sequence.

We describe an MRI technique for quantifying optic nerve atrophy resulting from a single episode of unilateral optic neuritis. We imaged 17 patients, with a median time since onset of optic neuritis of 21 months (range 3-81 months), using a coronal-oblique fat-saturated short-echo fast fluid-attenuated inversion-recovery (sTE fFLAIR) sequence. The mean cross-sectional area of the intraorbital portion of the optic nerves was calculated by a blinded observer from five consecutive 3 mm slices from the orbital apex forwards using a semiautomated contouring technique and compared with data from 16 controls. The mean optic nerve area was 11.2 mm2 in the affected eye of the patients, 12.9 mm2 in the contralateral eye (P = 0.006 compared to the affected eye) and 12.8 mm2 in controls (P = 0.03 compared to the affected eyes). There was a significant negative correlation between disease duration and the size of the affected optic nerve (r = -0.59, P = 0.012). The measurement coefficient of variation was 4.8%. The sTE fFLAIR sequence enables measurement of optic nerve area with sufficient reproducibility to show optic nerve atrophy following a single episode of unilateral optic neuritis. The correlation of increasing optic nerve atrophy with disease duration would be consistent with ongoing axonal loss in a persistently demyelinated lesion, or Wallerian degeneration following axonal damage during the acute inflammatory phase.

Adult↗

PubMed2001

Long-term remyelination after optic neuritis: A 2-year visual evoked potential and psychophysical serial study.

Thirty-one patients were followed-up, at 3-month intervals for the first year and at 6-month intervals for the second year, after an episode of optic neuritis. The object was to confirm previous evidence for a progressive shortening of visual evoked potential (VEP) latencies and to determine whether this is associated with any change in the clinical ocular examination, visual fields or contrast sensitivity. VEP latencies were found to decrease significantly during both the first and (less strikingly) the second year, the most marked changes occurring between 3 and 6 months. Contrast sensitivity improved during the first 9 months, but subsequently tended (non-significantly) to deteriorate. A similarly transient improvement in central visual field sensitivity was seen in a subgroup of patients with clinically overt multiple sclerosis. In the data from the acutely unaffected fellow eyes, no significant changes in VEP parameters or functional indices were observed. The findings extend those of a previous study which showed significant shortening of VEP latencies between 6 months and 3 years without significant functional improvement. Over this period, a significant prolongation of VEP latencies occurred in the asymptomatic fellow eye, accompanied by contrast sensitivity deterioration. Taken in conjunction, the two studies suggest that recovery processes involving remyelination or, possibly, ion channel reorganization proceed for at least 2 years. The concurrent effects of insidious demyelination and/or axonal degeneration (also occurring in the fellow optic nerve) are initially masked by the recovery process, but gradually become more evident. The functional benefits of the long-term recovery process are relatively minor and are usually reversed within a few years. Nevertheless, it is suggested that long-term remyelination may perform an important role in protecting demyelinated axons from degeneration. Understanding the factors which promote long-term remyelination may have significant implications for therapy in multiple sclerosis.

Adult↗

PubMed2001

The functional anatomy of single-word reading in patients with hemianopic and pure alexia.

We investigated single-word reading in normal subjects and patients with alexia following a left occipital infarct, using PET. The most posterior brain region to show a lateralized response was at the left occipitotemporal junction, in the inferior temporal gyrus. This region was activated when normal subjects, patients with hemianopic alexia and patients with an incomplete right homonymous hemianopia, but no reading deficit, viewed single words presented at increasing rates. This same area was damaged in a patient with pure alexia ("alexia without agraphia") and no hemianopia, who read words slowly using a letter-by-letter strategy. Although the exact level of the functional deficit is controversial, pure alexia is the result of an inability to map a percept of all the letters in a familiar letter string on to the mental representation of the whole word form. However, the commonest deficit associated with "pure" alexia is a right homonymous field defect; an impairment that may, by itself, interfere with single-word reading because of inability to see the letters towards the end of a word. The relative contributions of pure and hemianopic alexia in individual patients needs to be assessed, as the latter has been shown to respond well to specific rehabilitation programmes.

Adult↗

PubMed2001

Postpartum pituitary hypophysitis.

The case of a young woman who developed lymphocytic hypophysitis 2 weeks after delivery of a healthy baby is reported. The patient presented with clinical features suggestive of a pituitary mass lesion, but surgery was avoided when other clinical and radiologic features were considered. The patient recovered with steroid treatment only. We review the literature on this increasingly recognized condition and argue that medical management may be more suitable than previously thought.

Adult↗

PubMed2001

Assessing the risk of early multiple sclerosis in patients with clinically isolated syndromes: the role of a follow up MRI.

OBJECTIVES: With increasing evidence that permanent tissue damage occurs early in the course of multiple sclerosis, it is important that treatment trials include patients in the earliest stages of the disease. For many patients with multiple sclerosis the first presentation is a clinically isolated syndrome. Not all patients with a clinically isolated syndrome develop multiple sclerosis, however, and treatment of all such patients would be unwarranted. A single abnormal brain MRI identifies patients at a higher risk for the early development of multiple sclerosis, but current criteria are limited by either poor specificity (T2 lesions) or sensitivity (contrast enhancing lesions). The aim of the study was to assess the positive predictive value, sensitivity, and specificity of MRI indices for the development of multiple sclerosis after 1 year from two MRI examinations obtained 3 months apart. METHODS: MRI examinations were performed in 68 patients with a clinically isolated syndrome, with a clinical assessment after 1 year. RESULTS: Contrast enhancing lesions at both time points were the most predictive indices for developing multiple sclerosis (positive predictive value 70%) but had low sensitivity (39%). The combination of T2 lesions at baseline with new T2 lesions at follow up had the best overall positive predictive value (53%), sensitivity (83%), and specificity (76%). In patients with T2 lesions at baseline, the presence or absence of new T2 lesions at follow up significantly altered the risk of multiple sclerosis within 1 year (55% and 5% respectively, p<0.001). Multiple sclerosis also developed in 10% of patients with a normal baseline MRI. CONCLUSIONS: Serial imaging in patients with clinically isolated syndromes improved the positive predictive value, sensitivity, and specificity of MRI for the development of early multiple sclerosis and also identified patients at a lower risk of early multiple sclerosis than would have been expected from their abnormal baseline MRI. Selection of patients with clinically isolated syndromes for therapeutic intervention or clinical trials may benefit from serial MRI, to target those at greatest risk of early development of multiple sclerosis.

Adolescent↗

PubMed2001

Measurement of spinal cord area in clinically isolated syndromes suggestive of multiple sclerosis.

Atrophy of the spinal cord is known to occur in multiple sclerosis but the cause and the timing of its onset are not clear. Recent evidence suggests that atrophy may start to occur early in the disease. The aim was to determine whether atrophy of the spinal cord could be detected in vivo using MRI techniques, in patients presenting with a clinically isolated syndrome, which in many cases is the earliest clinical stage of multiple sclerosis. The cross sectional area of the spinal cord was measured in 43 patients presenting with a clinically isolated syndrome and 15 matched controls. T2 weighted imaging of the brain was also performed to determine the number and volume of high signal lesions consistent with disseminated demyelination. Both patients and controls were restudied after 1 year. The spinal cord area was significantly smaller in the 74% of patients with an abnormal brain MRI at presentation than in controls (mean areas 73.9 mm(2) and 78.1 mm(2) respectively, p=0.03). No significant difference was found in the spinal cord area between controls and patients with normal baseline brain imaging. The annual rate of change in patients did not differ significantly from controls. In conclusion, the finding of a smaller cord area in the subgroup of patients with clinically isolated syndrome with the highest risk of developing multiple sclerosis-that is, with an abnormal brain MRI, suggests that atrophy has developed in some patients with multiple sclerosis even before their first clinical symptoms. However, the lack of a detectable change in cord area over 1 year of follow up contrasts strikingly with the results of an earlier study of patients with relapsing-remitting multiple sclerosis, suggesting that the rate of atrophy increases as the disease becomes more established.

Adolescent↗

PubMed2001

Recurrent ptosis.

Explore the source record for details and available documents.

Blepharoptosis↗

PubMed2001

Relapsing intracranial Rosai-Dorfman disease.

Two patients presenting with recurrent visual impairment due to relapsing intracranial Rosai-Dorfman disease are described. In both patients a preoperative diagnosis of meningioma was made. Histological examination disclosed the characteristic picture of S100 and CD68 positive histiocytosis with prominent lymphophagocytosis. In both patients complete tumour removal by surgery was impossible with residual tissue being the origin of relapsing disease. Low dose radiation led to partial recovery of vision and resolution of the intracranial mass. Review of the literature on intracranial Rosai-Dorfman disease leads to the suggestion that postoperative radiotherapy may be advisable in all cases.

Aged↗

PubMed2001

A large family with hereditary spastic paraparesis due to a frame shift mutation of the spastin (SPG4) gene: association with multiple sclerosis in two affected siblings and epilepsy in other affected family members.

Hereditary spastic paraparesis (HSP) is a clinically and genetically heterogeneous neurodegenerative disorder characterised by progressive lower limb spasticity and weakness. Some forms have been associated with white matter lesions and complex phenotypes. This study was prompted by the diagnosis of multiple sclerosis (MS) in two sisters from a large pedigree with hereditary spastic paraparesis. Twelve affected members of the extended family were examined (MRI and EEG were carried out and evoked potentials measured in five), and historical information was obtained from six affected deceased persons. The inherited disease phenotype was confirmed as autosomal dominant hereditary spastic paraparesis associated with epilepsy in four affected persons. None of the extended family had evidence of MS. Genetic analysis of the family has shown linkage to chromosome 2p and sequencing of the spastin gene has identified a 1406delT frameshift mutation in exon 10. This kindred demonstrates the clinical heterogeneity of HSP associated with spastin mutations. The possible relevance of the concurrence of HSP and MS in the sib pair is discussed.

Adenosine Triphosphatases↗

PubMed2001

Infundibulohypophysitis in a man presenting with diabetes insipidus and cavernous sinus involvement.

Infundibulohypophysitis is an unusual inflammatory condition that affects the infundibulum, the pituitary stalk, and the neurohypophysis and may be part of a range that includes lymphocytic hypophysitis. Lymphocytic hypophysitis occurs mainly in women and most often presents in the later stages of pregnancy. Infundibulohypophysitis usually presents with diabetes insipidus and the cause remains unclear. The case of a 46 year old man with a 12 week history of polyuria and polydipsia is reported. Cranial diabetes insipidus was diagnosed on the basis of a water deprivation test. Initial cranial and pituitary imaging studies were normal. He subsequently developed symptoms of panhypopituitism over a period of 6-9 months and then, more acutely, developed diplopia secondary to a fourth nerve palsy. Further brain imaging studies disclosed an enhancing pituitary stalk and a left cavernous sinus lesion. An initial trial of immunosuppressive treatment did not help symptoms significantly. The diagnosis of infundibulohypophysitis was made on histological evidence. The patient was treated with prednisolone and methotrexate. At 9 months he is well, without symptoms, and the radiological abnormalities have resolved.

Anti-Inflammatory Agents↗

PubMed2001

Magnetization transfer imaging in patients with clinically isolated syndromes suggestive of multiple sclerosis.

BACKGROUND AND PURPOSE: In patients with multiple sclerosis (MS), reduced magnetization transfer ratios (MTRs) have been reported in white matter that appears normal on studies obtained with conventional imaging techniques. The stage in the disease when this first becomes detectable is unclear. The purpose of this study was to measure the MTR of normal-appearing white matter (NAWM) and lesions in patients with clinically isolated syndromes (CIS), many of whom are at the earliest stages of MS, and to determine the prognostic value of any observed changes. METHODS: Twenty-seven CIS patients and 13 matched control subjects were studied. The mean MTR was measured from 10 regions of NAWM and, when present, from lesions. The patients were followed-up clinically for a median of 12 months. RESULTS: There was no significant difference in the mean MTR between NAWM in control subjects (38.5% units) and that in CIS patients (38.4% units). After 12 months' follow-up, MS developed in 26% of the patients. The MTR of NAWM in these patients did not differ from that of the other patients or the control subjects. CONCLUSION: The reduced MTR in NAWM, described in established MS, was not detectable in patients with CIS. MTR did not provide prognostic information for this short period of follow-up.

Adult↗

PubMed2000

A hypothetical scheme for the brainstem control of vertical gaze.

OBJECTIVES: To develop a hypothetical scheme to account for clinical disorders of vertical gaze based on recent insights gained from experimental studies. METHODS: The authors critically reviewed reports of anatomy, physiology, and effects of pharmacologic inactivation of midbrain nuclei. RESULTS: Vertical saccades are generated by burst neurons lying in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). Each burst neuron projects to motoneurons in a manner such that the eyes are tightly coordinated (yoked) during vertical saccades. Saccadic innervation from riMLF is unilateral to depressor muscles but bilateral to elevator muscles, with axons crossing within the oculomotor nucleus. Thus, riMLF lesions cause conjugate saccadic palsies that are usually either complete or selectively downward. Each riMLF contains burst neurons for both up and down saccades, but only for ipsilateral torsional saccades. Therefore, unilateral riMLF lesions can be detected at the bedside if torsional quick phases are absent during ipsidirectional head rotations in roll. The interstitial nucleus of Cajal (INC) is important for holding the eye in eccentric gaze after a vertical saccade and coordinating eye-head movements in roll. Bilateral INC lesions limit the range of vertical gaze. The posterior commissure (PC) is the route by which INC projects to ocular motoneurons. Inactivation of PC causes vertical gaze-evoked nystagmus, but destructive lesions cause a more profound defect of vertical gaze, probably due to involvement of the nucleus of the PC. Vestibular signals originating from each of the vertical labyrinthine canals ascend to the midbrain through several distinct pathways; normal vestibular function is best tested by rotating the patient's head in the planes of these canals. CONCLUSIONS: Predictions of a current scheme to account for vertical gaze palsy can be tested at the bedside with systematic examination of each functional class of eye movements.

Animals↗

PubMed2000

Detection of ventricular enlargement in patients at the earliest clinical stage of MS.

The aim of this study was to determine whether atrophy could be detected at the earliest clinical stages of MS. Patients were selected from a 1-year follow-up MRI study of clinically isolated syndromes. Nine patients who developed MS were compared with eight matched patients who had no further symptoms. Significant ventricular enlargement occurred in the group that developed MS but not in the other group. Our findings show that atrophy, albeit mild, can be detected early in the course of MS.

Adolescent↗

PubMed2000

Epilepsy surgery, visual fields, and driving: a study of the visual field criteria for driving in patients after temporal lobe epilepsy surgery with a comparison of Goldmann and Esterman perimetry.

Twenty four patients who had undergone temporal lobe surgery for epilepsy were assessed to determine (a) whether or not they had developed a visual field defect and (b) if a field defect was present, were the visual field criteria, as required by the DVLA, fulfilled using the monocular Goldmann perimeter test and the automated binocular Esterman method performed on a Humphrey perimeter. A field deficit was found in 13 of 24 (54%) using the Goldmann perimeter and 11 of 24 (46%) by the Esterman method. The second was a more lenient assessment with six of 24 (25%) failing the driving criteria compared with 10 of 24 (42%) by the monocular Goldmann method. Three patients were seizure free but failed the driving criteria. This complication of surgery for temporal lobe epilepsy needs to be discussed with patients before surgery.

Adult↗