Peculiarities of direct bioelectrocatalysis by laccase in aqueous-nonaqueous mixtures.

The effect of concentration of ethanol and dimethyl sulfoxide on the catalytic activity of laccase is studied for the enzymatic reaction of catechol oxidation and bioelectrocatalytic reaction of oxygen reduction under the conditions of direct electron transfer. Laccase-Nafion composite is elaborated ensuring the enzyme stability in a wide potential range and a content of organic solvents. Based on the STM measurements, the structure of composite layer is proposed. It is shown that the mechanism of oxygen reduction reaction by laccase in organo-aqueous mixtures is similar to that earlier proposed for aqueous solutions. A decrease in the electrocatalytic activity of laccase in the oxygen reduction correlates with a decrease in the laccase enzymatic activity in the substrate oxidation. However, a decrease in the laccase activity in the composite is observed at a higher content of organic solvent in the mixture. The mechanism of laccase inactivation by organic solvents is proposed.

Nerve biopsy: indications and contribution to the diagnosis of peripheral neuropathy. The experience of the Born Bunge Foundation University of Antwerp and University of Liege between 1987 and 1997.

We reviewed 355 nerve biopsies analysed at the Laboratories of Neuropathology of the Born-Bunge Foundation/University of Antwerp (BBF/UIA) and University of Liège (ULg) between 1987 and 1997. We examined the indications for nerve biopsy, the yield of the procedure, and the influence of clinical and neuropathological parameters. Contributory biopsies accounted for 35.5% and 47.3% respectively at ULg and BBF/UIA laboratories: of these, one third showed specific histological findings, the majority being informative only when combined with the relevant clinical data. The profile of indications for nerve biopsy was roughly comparable in both laboratories. The search for an inflammatory neuropathy prompted 35-40% of all biopsies with more than 50% of specimens being informative in this indication. The lowest yield (20%) was obtained among the nerve biopsies performed in the absence of any presumptive aetiology. These accounted for 22-33% of all cases. Inadequate surgical resection, delays in transport or processing errors precluded histological study of 4% (BBF/UIA) to 8% (ULg) of the specimens. We conclude that nerve biopsies should be performed by experienced surgeons and handled in specialised laboratories. Only a relatively small number of causes of neuropathy can be diagnosed on the basis of histology alone. More often, contributory biopsies will result from the combination of non-specific suggestive histological features with relevant clinical information. The diagnostic yield of nerve biopsy is function of careful patient selection and close collaboration between the clinician and the neuropathologist.

Familial Kufs' disease presenting as a progressive myoclonic epilepsy.

Kufs' disease is the adult form of a group of disorders referred to as neuronal ceroid-lipofuscinosis or Batten's disease. We report here the clinical and anatomopathological features of two young brothers presenting with a progressive myoclonic epilepsy corresponding to type A of the disease according to Berkovic. The first clinical manifestations occurred before 20 years of age. Diagnosis was made in the older brother at autopsy and in the younger brother from a rectal biopsy. In addition to characteristic electron microscopic findings, enlarged neurons showed strong immunoreactivity against subunit c of mitochondrial ATP synthase which has been reported previously in only a few adult cases of neuronal ceroid-lipofuscinosis. An extensive review of the published cases underlines the rarity of this condition, particularly when onset is early.

Clinical and neuropathological parameters affecting the diagnostic yield of nerve biopsy.

The value of nerve biopsy in the investigation of peripheral neuropathies is an important and controversial issue, partially obscured by the large variations in the diagnostic yield routinely reported for this procedure. The aim of this study was to evaluate the clinical and neuropathological parameters affecting the yield of nerve biopsy. We compared the experience of two independent neuropathology laboratories with different patient recruitment and neuropathological methods over 11 years (01/1987-12/1997). Clinicopathological correlations were studied retrospectively in 355 patients. Using the same criteria of evaluation, contributive biopsies accounted for 35.5% in one laboratory, and 47.3% in the other. Clinical parameters affecting the yield of nerve biopsy were: (a) the presumptive diagnosis at time of referral for biopsy; (b) the distribution of symptoms; and (c) the interval between disease onset and biopsy. Greater yield was associated with clinically suspected vasculitis, inflammatory demyelinating neuropathy or hereditary sensorimotor neuropathies. Contributive findings were more often reported with multifocal or asymmetrical presentations, and onset-to-biopsy interval of less than 6 months. The contribution of nerve biopsy varied according to neuropathological techniques: (a) serial sections on frozen. paraffin-embedded and resin-embedded material improved sensitivity for interstitial pathology: (b) combined muscle biopsy increased sensitivity in the detection of vasculitis; and (c) teasing of nerve fibers added critical information to other classical techniques in only 4/102 cases.

A new combined bodian-luxol technique for staining unmyelinated axons in semithin, resin-embedded peripheral nerves: a comparison with electron microscopy.

Quantitation of unmyelinated fibers (UF) in peripheral nerves has classically relied upon ultrastructural morphometry. Because this method is time-consuming, it is not typically performed in routine analysis of nerve biopsies. We applied the Bodian-Luxol technique to detect unmyelinated axons by light microscopy on semithin sections from resin-embedded nerve tissue. Estimates were compared to ultrastructural counts. The staining appeared highly specific for axons. Excellent correlation was found between optic densities and the population of UF larger than 0.5 microm. The smallest profiles detected by light microscopy had a diameter close to 0.6 microm. This new technique is not a substitute for ultrastructural quantitative morphometry of UF, as very small unmyelinated axons, especially regenerating ones, can not be reliably visualized. However, it provides a valuable light microscopic method for evaluating axonal loss among UF.

Infantile and juvenile presentations of Alexander's disease: a report of two cases.

We describe 2 new cases of Alexander's disease, the first to be reported in Belgium. The first patient, a 4-year-old girl, presented with progressive megalencephaly, mental retardation, spastic tetraparesis, ataxia and epilepsy: post-mortem examination showed widespread myelin loss with Rosenthal fibers (RFs) accumulation throughout the neuraxis. She was the third of heterozygotic twins, the 2 others having developed normally and being alive at age 5 years. The second patient developed at age 10 years and over a decade spastic paraparesis, palatal myoclonus, nystagmus, thoracic hyperkyphosis and thoraco-lumbar scoliosis with radiological findings of bilateral anterior leukoencephalopathy. Brain stereotactic biopsy at age 16 years demonstrated numerous RFs. With these 2 cases, we review the literature on the various clinico-pathological conditions reported as Alexander's disease. We discuss the nosology of this entity and the pathogeny of RFs formation and dysmyelination. Clues to the diagnosis of this encephalopathy in the living patient are briefly described.

Shunt-related abdominal metastasis of cerebral teratocarcinoma: report of an unusual case and review of the literature.

OBJECTIVE AND IMPORTANCE: Internal drainage of cerebrospinal fluid to the abdominal cavity via a ventriculoperitoneal shunt (VPS) is a common procedure for therapy of obstructive hydrocephalus; because this condition is often caused by brain tumors blocking the natural cerebrospinal fluid pathways, the VPS as an artificial anastomosis can provide the means for the spreading of tumor cells by the cerebrospinal fluid. We report the case of a VPS-related abdominal metastasis of a teratocarcinoma and review the pertaining literature. CLINICAL PRESENTATION AND INTERVENTION: A 24-year-old man with a history of three brain tumors that were operated on when the patient was 14, 21, and 23 years of age developed an acute ileus 7 months after VPS insertion for cerebral teratocarcinoma. Intraoperatively, a massive abdominal tumor was observed, which turned out to be a peritoneal metastasis of the aforesaid brain tumor. The patient died as a result of his illness 1 month later. RESULTS: To date, 58 VPS-related metastases of brain tumors have been described. The male-to-female ratio is 1.6:1, the mean age at shunt insertion is 12.2 years, and the interval between shunt operation and diagnosis of metastases is 16.8 months. During the observation time, 69.2% of the patients died as a result of their illness or abdominal metastases. The most common sources of the metastases were germinomas (27.7%), medulloblastomas (19.1%), and endodermal sinus tumors (10.3%). CONCLUSION: The presented case is only the second VPS-related abdominal spreading of a cerebral teratocarcinoma. Metastases via VPS are rare but should be considered as a possible complication and mode of systemic spread in patients with primary intracranial malignancy.

Preoperative evaluation of 54 gliomas by PET with fluorine-18-fluorodeoxyglucose and/or carbon-11-methionine.

UNLABELLED: This study evaluates the usefulness of PET for the preoperative evaluation of brain gliomas and methods of quantification of PET results. METHODS: Fifty-four patients with brain gliomas were studied by PET with 18F-fluorodeoxyglucose (FDG) (n = 45) and/or 11C-methionine (MET) (n = 41) before any treatment. Results of visual analysis, calculation of glucose consumption and five tumor-to-normal brain ratios for both tracers were correlated with two histologic grading systems and with follow-up. RESULTS: Visual analysis (for FDG) and tumor-to-mean cortical uptake (T/MCU) ratio proved to be the best tools for the evaluation of PET results. Methionine was proven to be better than FDG at delineating low-grade gliomas. Tumor-to-mean cortical uptake ratios for FDG and MET were clearly correlated (r = 0.78), leading to the equation T/MCU(FDG) = 0.4 x T/MCU(MET). We showed a good correlation between FDG PET and histologic grading. MET uptake could not differentiate between low-grade and anaplastic astrocytomas but was significantly increased in glioblastomas. Low-grade oligodendrogliomas exhibited high uptake of FDG and MET, probably depending more on oligodendroglial cellular differentiation than on proliferative potential. Uptake was decreased in anaplastic oligodendrogliomas, probably due to dedifferentiation. Care must be taken with peculiar histologic subgroups, i.e., juvenile pilocytic astrocytomas and oligodendrogliomas, because of a discrepancy between high PET metabolism and low proliferative potential (good prognosis). Both tracers proved useful for the prediction of survival prognosis. Methionine proved slightly superior to FDG for predicting the histologic grade and prognosis of gliomas, despite the impossibility of differentiation between Grades II and III astrocytomas with MET. This superiority of MET could be explained by patient sampling (low number of Grade III gliomas submitted to examination with both tracers). The combination of both tracers improved the overall results compared to each tracer alone. CONCLUSION: Both tracers are useful for the prediction of the histologic grade and prognosis. The apparent superiority of MET over FDG could be due to the small number of Grade III gliomas studied with both tracers.

Painful hyperplasia and hypertrophy of pacinian corpuscles in the hand: report of two cases with immunohistochemical and ultrastructural studies, and a review of the literature.

Hypertrophy and hyperplasia of pacinian corpuscles in the hand are very rare, with only 29 cases previously published. We describe two new cases in middle-aged patients whose chief complaint was progressive digital pain. Immunohistochemical and electronmicroscopic investigations indicated that the lump replicates the structure of enlarged pacinian corpuscles and should not be considered as a real tumor, nor connected to neurofibromatosis. No recurrence was observed after surgical excision. Although local trauma was encountered in 55% of the reported cases, the pathogenesis of such a lesion is still speculative.

Predegenerated nerve allografts versus fresh nerve allografts in nerve repair.

This study reevaluated the possibility of using predegenerated nerves as donor nerve allografts for nerve repair and compared the results of functional recovery to those obtained after standard, fresh nerve allograft repair. Twenty donor rats underwent a ligature/ section of the left sciatic nerve 4 weeks before nerve graft harvesting. Forty recipient rats underwent severing of the left sciatic nerve leaving a 15-mm gap between the nerve stumps. Graft repair was undertaken using either the predegenerated left sciatic nerve of the 20 donor rats (predegenerated group, 20 recipient rats) or the normal right sciatic nerve of the 20 donor rats (fresh group, 20 recipient rats). Recovery of function was assessed by gait analysis, electrophysiologic testing and histologic studies. Walking tracks measurements at 2 and 3 months, electromyography parameters at 2 and 3 months, peroperative nerve conduction velocity and nerve action potential amplitude measurements at 3 months, as well as assessments of myelinated nerve fiber density and surface of myelination showed that fresh and predegenerated nerve grafts induced a comparable return of function although there was some trend in higher electrophysiologic values in the predegenerated group. The only slight but significant difference was a larger mean nerve fiber diameter in the nerve segment distal to a predegenerated nerve graft compared to a fresh nerve graft. Although our study does not show a dramatic long-term advantage for predegenerated nerve grafts compared to fresh nerve grafts, their use as prosthetic material is encouraging.

Idiopathic hypertrophic cranial pachymeningitis mimicking multiple meningiomas: case report and review of the literature.

A case of idiopathic hypertrophic cranial pachymeningitis with an unusual and misleading manifestation is reported. Computed tomography scan, angiographic and magnetic resonance imaging findings were suggestive of multiple meningeal neoplasms and a correct diagnosis was made only after meningeal biopsy. This 44-year-old patient had a previous history of an ill-defined systemic disorder associating episcleritis, erythroderma nodosa and multiple peripheral arthritis. We review previous reports of idiopathic cranial pachymeningitis with emphasis on radiological investigation techniques, histopathology and possible dysimmune mechanisms of pathogenesis.

Gliomatosis cerebri: clinical, radiological and pathological report of a case with a stroke-like onset.

A 62 year-old man was admitted with a right hemiparesis, sensory aphasia and right hemianopia which appeared on awakening. He was initially thought to have a stroke, but EEG showed diffuse slowing and both CT scan and MRI irregular white matter lesion suggesting a leucoencephalopathy. His neurological deficit regressed, and he was discharged after 2 weeks. He was readmitted 6 months later because of mental confusion. MRI revealed diffuse white matter lesions extending up to the frontal lobes, these were hyperintense on T2 weighted images and suggested the diagnosis of gliomatosis cerebri (GC). The patient became progressively comatose and died 6 weeks later. At autopsy the brain looked diffusely swollen with irregular greyish areas of the white matter of both centrum ovale and brain stem. On microscopic examination the cerebrum and brain stem were diffusely and asymmetrically infiltrated by numerous neoplastic glial cells without angiogenesis or disruption of architectonic boundaries. There were no mitoses nor necrosis. Many tumour cells were GFAP- and S100-positive. A high proportion of cells contained the leucocyte antigen Leu-7. This case of gliomatosis cerebri is compared to the 9 published cases of GC with an initial focal neurological deficit and to the 19 publications reporting MRI results. The controversial nosological boundaries and etiopathogenetic hypotheses of this peculiar neoplastic disease are discussed.

[Structure and functions of the cutaneous nervous system]. / Structure et fonctions du système nerveux cutané.

Cutaneous nerves are either somatic sensory afferents to ganglion neurons or terminal efferents from the autonomous nervous system. Myelinated somatic nerves form subcutaneous and intradermal plexus from which arise various types of endings: free, dilated and included in corpuscles. Free terminals are ramified in the dermis, epidermis and the epithelial sheet of hairs. Dilated terminals are lanceolate fibres around hairs and those in close contact with Merkel cells. Well identified corpuscles are those of Meissner, Ruffini and Pacini. Physiologically, nerves are involved as mechano-, thermo- and pain receptors. Five mechanoreceptors are recognized according to their rate (slow/fast) of adaptation and their receptive field (type I, small; type II, large): Merkel cells (SA I), Ruffini corpuscles (SA II), Meissner corpuscles (FA I), Pacini corpuscles (FA II) and palisades of lanceolate nerve endings (FA with various field units). Thermo- and nociceptors are mainly thin unmyelinated free nerve endings with various rates of conduction velocity. The autonomic nervous system supplies sympathetic innervation appearing as unmyelinated small nerve endings in close contact with skin appendages, except sebaceous glands. Only sweat glands are innervated by cholinergic terminals.

Type II to type I transformation of chronically stimulated goat latissimus dorsi muscle: a histoenzymological, biochemical, bioenergetic, and functional study.

Five goat latissimus dorsi muscles (LDM) were submitted to a progressive chronic electrostimulation program to reach an integrated understanding of the fast-to-slow transformation process in large mammals. LDM were regularly sampled and followed during a period of 8 months. Each sample was simultaneously assessed for histoenzymological study, myosin and LDH isoforms and bioenergetic capacities [NADH dehydrogenase cytochrome c oxidoreductase (NADH Cyt c OR), succinate dehydrogenase cytochrome c oxidoreductase (Succ Cyt c OR), cytochrome c oxidase (Cyt c Ox) and LDH]. Such muscles were also tested with and without completion of II to I transformation for their mechanical properties in isometric and isotonic strain gauge testing. The conversion of fast-to-slow myosin monitored by heavy chain (HC I) and light chain slow component (LC2s) began a few days after stimulation and was almost 100% after 100 days. The H-LDH isoforms evolved similarly but did not reach 100% conversion after 200 days. The activity of respiratory chain oxidases increased within 36 h but to a variable extent and peaked after 32 days, corresponding to a 75% transformation of myosin compared to initial levels. NADH Cyt c OR, Succ Cyt c OR, and Cyt c Ox, respectively increased 10-, 5- and 5-fold. These activities then significantly decreased before the completion of the myofibrillar transformation and reached a plateau with stable activities that remained 2- to 3-fold higher than the unstimulated LDM. LDH activity sharply decreased until day 62 (5-fold) and then plateaued. Functionally, muscle showed a reduced speed of contraction and moderate reduction in power output but had become fatigue-resistant. This study documents the transformation process in large mammals and suggests the dynamic relation between workload, aerobic-anaerobic metabolism and the contractile myofibrillar system.

Agrammatism in Spanish: a case study.

This article presents a case study of a Spanish-speaking Broca's patient with a selective deficit in syntactic production. The analysis indicates difficulties in processing certain abstract categories such as clitic pronouns without any other significant morphological errors. This pattern and the abundant use of strong pronouns in subject position are accounted as a syntactic production deficit related to the computation of phonetically null elements e that enter in a syntactic chain. At the same time, the patient shows a milder problem in the production of canonical word order at the sentence level, which is also explained in syntactic terms.

[An unusual complication of cervicofacial lift: paralysis of the external branch of the accessory spinal nerve]. / Une complication exceptionnelle du lifting cervico-facial: la paralysie de la branche externe du nerf spinal.

Paralysis of the lateral branch of the accessory nerve is an extremely rare lesion during cervico-facial facelift. Based on 3 detailed and published personal cases observed over a period of 15 years, the authors review the literature, revealing a total of 9 cases over a period of 30 years, but other cases have probably not been published. Their review reveals the following points. This is an exceptional lesion. However, the nerve can be damaged as it emerges from the posterior border of the sternocleidomastoid muscle during slightly deep dissection and the electrical scalpel must be used cautiously. Even, partial paralysis of the trapezius muscle induces pain and considerable functional impairment with partial permanent disability. The natural history of this paralysis is very long and may be followed by regression after several years. Although there is an obvious cause-and-effect relationship between the operation and accessory nerve paralysis, it is always difficult to attribute this lesion to a possible surgical error, as the exact mechanism of the nerve lesion remain hypothetical and once again raises the problem of therapeutic risk.

Functional categories in agrammatism.

This paper comments on Hagiwara's (1994b, this volume) proposals to account for the language deficits found in agrammatic aphasia, with special emphasis on Functional Categories (FCs). Some contemporary assumptions about FCs are reviewed focusing on their contentfulness, morphological features, and depiction as a heterogeneous set. This paper also discusses the view that the target of impairment in agrammatism constitutes a natural class. Treatment of FCs in their connection to chains and Lexical-Relatedness is discussed in terms of feature checking and morphological characteristics.

Radiation-induced gliosarcoma. Case report and review of the literature.

A 13-year-old boy presented with a cerebral gliosarcoma 12 years after having acute lymphoblastic leukemia treated by chemotherapy and central nervous system prophylaxis treated by radiation therapy (24 Gy) and intrathecal methotrexate. A review of the literature disclosed 129 possible radiation-induced gliomatous and/or sarcomatous brain tumors: namely, 89 gliomas, 36 sarcomas, and four gliosarcomas, including the present case. An analysis of these cases revealed several characteristics that differentiate them from similar spontaneous brain tumors, thus providing arguments for the carcinogenic effect of radiation therapy on intracranial tumors.