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At least 739 records · Page 41Linked to original sources
PubMed1989

Intracranial abnormalities associated with facial plexiform neurofibromas in neurofibromatosis type 1.

From 1975 to 1988 seventeen patients with neurofibromatosis type 1 and a disfiguring facial plexiform neurofibroma (FPN) were investigated. The FPN was left-sided in 13 patients. It was orbital/periorbital in 4, lower facial in 7 and involved the whole face in 6 subjects. Neuroimaging (n = 13) revealed a tumor (of optic pathways or basal ganglia) in 8, an ipsilateral middle cranial fossa arachnoid cyst in 2, multiple areas of high signal intensity (in T2-weighted magnetic resonance imaging) in 1, and normal findings in 2 patients. In NF-1 patients with FPN there seems to be a high incidence of intracranial tumors and possibly of arachnoid cysts. Our observation has to be confirmed in a larger patient series.

Adolescent↗
PubMedDate not supplied

Surgical treatment of Graves' ophthalmopathy by decompressive orbitotomy.

Malignant exophthalmos is often not resolvable using only medical or radiation therapy. The pressure on the optic nerve which is generally associated with it evolves rapidly in many cases towards optic atrophy and subsequently loss of vision. Only surgical treatment offers any guarantee of success and of the various techniques proposed, subfrontal orbital decompression seems clearly the more effective, in that it makes for an optimal alleviation of pressure in the optic pathways. The Authors describe their technique, a variation on the original approach, and report the results achieved with it.

Adult↗
PubMed1987

Neurofibromatosis.

Neurofibromatosis (NF) is a spectrum of disorders that manifest in a variety of ways. As part of the NF spectrum, many different anatomic abnormalities can develop that cause neurologic problems. The central nervous system may be directly involved or may be affected by tumor impingement. Optic pathway gliomas may also occur. The multiple neurofibromas characteristic of the most common form of NF, Von Recklinghausen disease, have a propensity to grow anywhere along nerve pathways. Therefore, the peripheral nervous system can be extensively involved. The neurofibromas may range in size from small, circumscribed tumors to gigantic plexiform tumors that insinuate into adjacent normal tissues and may compromise their function. Other neurologic problems of a functional nature can occur as well: learning disabilities, seizures, incoordination, and sensory abnormalities, among others. Computerized tomography (CT) and magnetic resonance imaging (MRI) scans are valuable diagnostic studies for identification and follow-up of tumors and other neurologic problems that may be investigated with these techniques. Plain radiographs are useful for investigating skeletal abnormalities in the skull, the ribs, the spine, and the limbs. Neurologic studies, including electroencephalography (EEG), brain-stem evoked response (BSER) or auditory brain stem response (ABR), visual evoked response (VER), nerve conduction velocity (NCV), and electromyography (EMG) provide additional information regarding specific symptom-indicated problems.

Humans↗
PubMed1986

[Clinical value of the colored contrast sensitivity test. Preliminary note].

Evaluation of color contrast sensitivity is a new test for the assessment of visual capacity and especially of light stimulation transfer along the optic pathway. The color technique yields more accurate results. It is combined with previously existing functional examinations and allows very early detection of subclinical signs of starting pathological processes.

Color Perception Tests↗
PubMed1987

Assessment of visual function in MS patients: comparative study of some diagnostic tests.

Optic pathways are frequently involved in Multiple Sclerosis (MS). However, in some cases the involvement is asymptomatic or gives rise to only slight visual disturbances without alterations of visual acuity or of clinically evident visual field defects. In these cases several diagnostic tests permit an objective evaluation of the visual dysfunction. The aim of this study is to compare the value of contrast sensitivity test (CST), pattern reversal visual evoked potential (VEP), ophthalmoscopy, Goldmann perimetry in 45 MS patients with normal visual acuity. Examination of contrast sensitivity was carried out with a simple two-alternative forced choice test estimating the spatial frequency of 4 cycles/degree. The VEP was performed with a pattern reversal checkerboard at a spatial frequency of 1 and 2 cycles/degree. Fundus examination was abnormal in 12 patients; visual field defects were detected in 16 patients. 32 patients (71.1%) had abnormal CST in one or both eyes. VEP for the 30' checks was abnormal in 32 cases (71.1%) and that for the 15' checks in 36 cases (80.0%). All but 4 patients (91.2%) had one or more abnormal tests. All patients with abnormal perimetry and/or fundus examination had also CST and/or VEP altered. It is apparent that CST and VEP reveal a significant proportion of abnormalities in the visual system that have not been revealed by routine neuroophthalmological examination.

Adolescent↗
PubMed1979

[Disseminated sclerosis: diagnostic value of neurophysiological investigations (author's transl)].

Demyelinisation lesions of disseminated sclerosis actually present within the white matter are much more numerous than clinical manifestations would suggest that the majority of these lesions are clinically latent. Ophtalmologists were the first to seek a functional deficit reflecting the demyelinisation which so often affects the optic pathways. In practice, the recording of evoked visual potentials has proved to be the most reliable method. The brain stem is another region where demyelinisation lesions are frequent and quite often latent. Electronystagmography offers a highly sensitive means for the investigation of internuclear connections, whilst other authors use evoked auditory potentials. Similarly, evoked somaesthesic potentials make it possible to reveal lesions of the lemniscal tract.

Demyelinating Diseases↗
PubMed1985

[Cerebral lymphoma associated with lesions of multiple sclerosis].

A 24 year-old man experienced a left retrobulbar neuritis which improved completely after 2 months of non-steroid antiinflammatory therapy. One month after the end of the treatment he developed a Korsakoff-like amnestic syndrome. Three months later he complained of horizontal diplopia. A CT Scan showed a diffuse enhancement of the periventricular areas, corpus callosum and fornix. Diplopia and CT scan abnormalities disappeared after the administration of tetracosactide. Subsequently a progressive worsening of the neurological condition developed, including a 1 1/2 syndrome of Fisher. In C.S.F. proteins ranged from 35 to 66 mg/dl, gammaglobulins from 4 to 5 per cent, cells from 2.2 to 6.8 per mm3 without abnormal cells. Rounded areas of enhancement were observed on CT scan in pons and right occipital lobe. Usual biological tests, abdominal echography and lymphography were normal. Death occurred 15 months after the onset of symptoms. Neuropathological examination showed: 1) a cerebral lymphoma of probable B origin with distinct masses in right occipital lobe and pontine tegmentum and a more diffuse perivascular infiltration on the left side in the amygdaloid nucleus, fourth temporal gyrus, sublenticular area, hypothalamus and in the right internal capsule; 2) multiple small clear-cut foci of demyelination with myelin-axonal dissociation bilaterally in the optic pathways, periventricular regions, corona radiata, cerebral and cerebellar white matter, sublenticular areas, temporal lobes, splenium of the corpus callosum and fornices with secondary atrophy of the mamillary bodies. Both recent and old plaques were observed. Inflammatory perivascular cuffing, when present, consisted of small nontumoral lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Does timing of axon outgrowth influence initial retinotectal topography in Xenopus?

The question of whether timing is involved in generating the topographic organization of the earliest embryonic projection from the retina to the tectum has been examined in Xenopus laevis. First, the normal schedule of axonal outgrowth from the retina to the tectum was characterized. Groups of axons originating from either dorsal or ventral extremes of the retina were labeled by in vitro incubation of sectors (one-quarter to one-third) of eye primordia in [3H]proline and their time courses of outgrowth were determined using light microscope autoradiography. Comparisons of the growth of dorsal and ventral nerve fiber populations showed that those from the dorsal retina leave the eye first, grow along the optic pathway, and reach the tectum roughly 6 hr ahead of those from the ventral retina. This stereotyped sequence of outgrowth schedules the development of the initial retinotectal map: first the ventrolateral tectum receives input from the dorsal retina (stage 37/38), and then the dorsomedial part receives input from ventral retina (stage 40). Second, to test whether the accurate timing of axon outgrowth and target invasion defines the spatial ordering of the earliest connections, the normal schedule of retinal fiber outgrowth was altered by substituting dorsal halves of young stage 21 eye primordia, labeled with [3H]proline, for those in older stage 27 embryos. These heterochronic transplants resulted in retarded outgrowth from the dorsal retina such that the original pioneer fibers reached the tectum at least 9 hr later than normal, arriving after ventral retinal fibers, thereby reversing the normal sequence of tectal invasion. Despite this, the initial pattern of tectal innervation remained spatially normal. It is concluded that the retinotectal map is generated not by the temporal sequence of retinal axon outgrowth but, rather, by selective means of neuronal recognition.

Animals↗
PubMed1982

Electroretinography and visual evoked responses in paediatric practice.

Electroretinography an the recording of visual evoked responses are of considerable value as ancillary investigations in clinical ophthalmology, paediatric neurology an developmental paediatrics. The techniques used are non-invasive and yield objective results without any need for patient co-operation. In this study 159 children were examined using a system constructed from apparatus available in South Africa. Indications for the investigations included developmental delay, acute intracranial disease, eye disease and cerebral degenerative disorders. Information obtained made possible distinctions between retinal dysfunction and lesions of optic pathways, the occipital cortex and higher cortical centres.

Adolescent↗
PubMed1980

[Radioautographic study of the connections between field 17 of the cat visual cortex and the hypothalamus].

At different time after administration of tritium-labelled amino acids, in field 17 of the optic cortex, the label was detected in all hypohalamic areas except the ventromedial nucleus. This phenomenon, while supporting and verifying our previous investigations, demonstrates that there exist some direct spatial organizaional bilateral cortico-hypothalamic connections. Normal ultrastructure of the synaptic contacts was studied by means of electron radioautography. Advantages and disadvantages of the radioautographic method are discussed and compared to some modern methods of anterograde degeneration applied for investigating connections in the CNS. A suggestion s made on the role of the connections detected in formation of responses to the information obtained via the optic pathways when the hypothalamus participates in regulating some functions.

Animals↗
PubMed1995

[Craniopharyngiomas. Neurosurgical treatment and therapeutic results].

From 1984 to 1993, 24 patients were operated for craniopharyngeoma at the University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. We undertook a retrospective study based on the patients' records in order to elucidate the course of the illness from the time of diagnosis until the end of treatment. The median age of the patients was 35 years (range 1.5-75 years). The follow-up period was one month-9.5 years. Preoperatively most patients had symptoms or clinical signs of compression of the optic pathways. Eighteen patients were operated by the transcranial route and six patients by the transsphenoidal route. Radical excision was achieved in 10 cases. Nine patients had recurrence of tumor. Postoperative endocrine disturbances were diagnosed in 19 cases. By the end of the follow-up eight patients were dead, of whom seven had had relapse of tumor. We recommend radical excision at the primary operation whenever possible, but the issue is controversial.

Adolescent↗
PubMedDate not supplied

[Dyschromatopsia: manifestation or epiphenomenon in the course of diabetic neuropathy].

We performed a study in 92 diabetic patients (76 Type 1 and 16 Type 2) without retinopathy to determine the relation between diabetic dyschromatopsia and neuropathy, which has been evoked in previous studies. Color vision was explored with Lanthony's desaturated D 15 panel. Peripheral nervous function was explored with an electrophysiological score which has been beforehand validated. Moreover evoked visual potentials were performed in 38 diabetic subjects in order to determine whether dyschromatopsia was related to an impairment of central optic pathways. Fifty-one among the 92 diabetic subjects had a blue-yellow dyschromatopsia. Among the recorded parameters, only peripheral nervous impairment was significantly more frequent in the group with dyschromatopsia than in the group without. Ten among 38 diabetics had impairment of the evoked visual potentials. Frequency of alteration of evoked visual potentials was not different between the group with and the group without dyschromatopsia. Our results confirm the relationship between dyschromatopsia and the alteration of the nervous function in diabetic subjects. In return, lack of significant modification of evoked visual potentials among diabetic patients with dyschromatopsia and the blue-yellow axis of dyschromatopsia are in opposition with a direct neurological origin of dyschromatopsia. We therefore evoke a common process in the beginning of the diabetic dyschromatopsia and of peripheral neuropathy.

Adolescent↗
PubMed1976

[Cytoarchitecture of the principle diencephalic visual centers in the embryo and the chicken Gallus domesticus L. Experimental study].

The effects of the bilateral removal of the optic vesicle on the cytoarchitectonics of the main diencephalic visual centres of Gallus domesticus L. embryos and chicken have been studied from the 10th, day of incubation until the 15th, day after hatching. - Without afferent optic pathways there is no significnat change in cellular components of nucleus lateralis anterior, nucleus geniculatus lateralis ventralis, nucleus griseus tectalis, nucleus rotundus and nucleus pretectalis principalis. When these centres have specific organization, one may observe a spatial distribution of neurons different from that of unoperated chickens. - Whereas the nucleus ectomamillaris disappears early, the nucleus superficialis synencephali is not differentiated. the nucleus geniculatus lateralis dorsalis, reduced in size, shows an alternation of cell constitution even if cytoarchitectonics appears to be similar to that of unoperated chickens. A comparison of these results with those on tectum opticum by authors brings up the question of the exact nature of retino-thalamic connections and of their morphogenetic role. If morphogenetic influence appears to be certain on some structures it seems to be limited on others.

Age Factors↗
PubMed1977

[Determination of urobilinoide concentration in the urine. New rapid method for clinical determination of urinary-urobilinoids using the Ehrlich-reaction].

A rapid method for quantitative determination of concentration of urobilinoids of fresh urine was developed. The method is based upon extraction of urinary urobilinoids using a mixture of acetic acid and ether and followed by the extraction of the ethereal phase with Ehrlich reagent and a solution of sodium acetate. Readings of absorbance from the absorption band of reaction products from urobilinoids and Ehrlich reagent are done. Performance of the rapid method: 2 ml urine + 10 ml ether + 2 ml acetic acid were thoroughly mixed for about 15 seconds. The ethereal extract was shaken after addition of 12 ml Ehrlich-reagent for 1 minute and 15 ml half-saturated sodium acetate solution were added. 0-3 minutes afterwards reading of absorption at 560 nm respectively filter Hg 578 nm. Photometer:mg/dl=29 X A578 nm, 1 cm -0,4. Spectrophotometer:mg/dl urobilinoids=13,7 X A560 nm X 1/d -0,22 (d=optical pathway). Photometrical determination of concentration of urobilinoid can also be done using table 1. Accuracy, reproducibility and specificity are fully satisfying for clinical use of the method.

Ethers↗
PubMedDate not supplied

Intracranial supratentorial tumors: classification, clinical findings, surgical management.

Pediatric supratentorial tumors represent about 50% of all intracranial neoplasms. The most frequent tumors of the cerebral hemispheres are gliomas that arise from astrocytes, oligodendrocytes or ependymal cells. The incidence of the different histologic types is difficult to be established as many tumors have a mixed cellularity, thus classification is based on the prevalent oncotype or the most malignant component. Choroid plexus papillomas and ependymomas are the most common ventricular neoplasms. However, subependymal giant cell astrocytomas, subependymomas, teratomas are also observed. The parasellar region is a frequent site of pediatric tumors as craniopharyngiomas, optic pathway gliomas and germinomas. Pinealomas are less common. Signs and symptoms related to increased intracranial pressure are often reported and vary according to the patient's age. Macrocrania and a bulging fontanel can be observed in infants and toddlers, whereas headache, papilledema and vomiting are present in the older children. A tumor hindering CSF circulation may cause hydrocephalus. Focal signs include epilepsy and neurological deficits characteristic of tumor location. Total removal of the tumor is the ideal surgical therapy. When eloquent areas are involved, partial exeresis is indicated. Radiotherapy is usually administered to malignant tumors even if in younger children its use in markedly limited by the possible severe side-effects on the developing brain. Chemotherapy seems effective in some brain neoplasms, however most suitable drugs and dose need to be established. It may represent an alternative to radiotherapy in children less than three years of age.

Child↗
PubMed1996

[Neurofibromatosis type I (NF1): peculiarities and complications].

The clinical, radiological and genetic peculiarities of neurofibromatosis type 1 (NF1) or the von Recklinghausen disease are shown. The most common complications of this syndrome are presented. These are optic pathways gliomas and some other tumors of the nervous system and of any other location in the body; oseous alterations with skoliosis, pseudoarthrosis and facial dysplasias as the most important; aqueductal stenosis that frequently appears at the puberty or at adult life; an intellectual level lower than their brothers and sisters without NF1, and some less frequent complications such as endocrinological disorders and corpus callosum agenesis.

Adolescent↗
PubMed1996

Color vision loss among styrene-exposed workers neurotoxicological threshold assessment.

Styrene represents nowadays one of the most used organic solvent. The current exposure limit proposed for this chemical differs significantly from country to country: the Threshold Limit Value-Time Weighted Average (TLV-TWA) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH) is 50 ppm while the German, Finnish and Swedish occupational exposure limit is 20 ppm. Nevertheless, effects on the nervous system were recently reported in workers exposed at TWA styrene levels below the current TLV. Neuro-optic pathways have been shown to be particularly vulnerable to organic solvent exposure. Analysis and measurements of visual functions can provide important information on early neurotoxic effects. Previous studies support the hypothesis that styrene exposure can induce a dose-dependent color vision loss. The aim of this study is to assess a threshold level below which no detectable effect occurs for color vision. We applied a sub-application of the change point problem in two-phase regression considering one phase as a constant line. In accordance with this model the maximum-likelihood technique was used as a method to examine the dose- effect relationship between external styrene exposure and chromatic discrimination. The present article presents a joint analysis of data from two previously published studies, one carried out in Canada and the other in Italy. The age and seniority of the workers from both countries were remarkably similar, as were the process type, the chemicals used and the work-tasks of exposed subjects. The mathematical method presented here shows the existence of a statistically significant threshold. This finding shows that, in fiberglass-reinforced plastics industry, visual color impairment could be significantly detected above 4 ppm (upper limit of the confidence interval at 5% = 26 ppm). The exact clinical meaning of this effect, and also the progress of the impairment in exposed workers, is still to be assessed in further studies. The results of our study support the need of a reduction of the occupational limits for styrene in workplaces to values close to or lower than German, Finnish or Swedish exposure limits.

Adult↗