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The twelfth century was a period of transmission and absorption of Arabic learning though it filtered outside of the Arabic world as early as the second half of the tenth century. In general, the lure of Spain began to act only in the twelfth century, and the active impulse toward the spread of Arabic mathematics came from beyond the Pyrenees and from men of diverse origins. The chief names are Adelard of Bath, Robert of Chester, Hermann of Carinthia and Gerard of Cremona. In this time the Latin world became acquainted with the Hindu numerals, the Arabic Algebra and Euclid'sElements. However, not only Spain, but also the Norman kingdom of southern Italy and Sicily occupies a position of peculiar importance, though the works of the translators did not become very influential. There were made direct translations from Greek into Latin. One had to wait a century more to obtain a translation from Greek into Latin of the chief Archimedean scientific and mathematical treatises by William of Moerbeke. In the thirteenth century Fibonacci and Jordanus Nemorarius stand at the threshold of European mathematics. Not only was Fibonacci the first to explain Arabic arithmetic, but his works, especially his later ones, contain many original ideas. Jordanus continued the Greco-Roman tradition rather than the Greco-Arabic one, but he did so with much independence. To Nicole Oresme (fourteenth century) was due a broadened view of proportionality, a geometric proof to determine the summation of convergent infinite series and the proof, evidently the first in the history of mathematics, that the harmonic series is divergent. The Configuration Doctrine was treated by Merton College authors and by Oresme. In the fifteenth century theDe triangulis omnimodis of Regiomontan, a systematic account of the methods for solving triangles, marked the rebirth of trigonometry.

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The relation between age, sex and presence of polyglucosan bodies in the brain has been systematically studied in 64 patients who did not suffer from neurological brain disorders and in 2 cases with Lafora's disease. In the normal brain the number of polyglucosan bodies is related to increasing age. Under the age of 40, polyglucosan bodies can be found sporadically in cases without a neurological disorder, but in the cases of Lafora's disease their number is uncomparatively higher. A sex relation has not been found.

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The effectiveness of ritanserin, a selective 5-HT2 and 5-HT1c antagonist, in reducing negative symptoms in schizophrenia was investigated in a double-blind, placebo-controlled trial. Trial treatment was added to a stable neuroleptic treatment in 33 schizophrenic patients with predominantly negative symptoms. Ritanserin reduced the negative symptoms, as measured with the SANS. The main reduction was for the items facial expression, global affective flattening, and relationships with friends and peers. Also a reduction in total BPRS score was found, which approached statistical significance. Significant reductions were observed for the BPRS items emotional withdrawal and depressive mood. Ritanserin or other drugs blocking 5-HT2 and/or 5-HT1c receptors could be important in reducing specific symptoms in schizophrenic patients.

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The diagnostic value of axilla skin biopsy has been investigated in a patient with adult polyglucosan body disease. The biopsy data have been compared with those of control subjects and with those from previously reported patients with Lafora's disease. In a patient with adult polyglucosan body disease and in patients with Lafora's disease, an abundance of polyglucosan bodies was found in the myoepithelial cells of the axillary apocrine glands. In the control group of subjects, polyglucosan bodies were only sporadically seen. Axilla skin biopsy is, therefore, an easy and reliable method for confirming the diagnosis of adult polyglucosan body disease.

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The presence of polyglucosan bodies in sural nerves collected over a 16-year period was studied in relation to age, sex, presence of polyneuropathy, and concomitant presence of central nervous system disorder. Polyglucosan bodies have been seen in only one patient without a polyneuropathy. This patient was suffering from Lafora's disease. In all other sural nerves positive for polyglucosan bodies a polyneuropathy was present. Within this group the prevalence of polyglucosan bodies was positively correlated with age, and if a central nervous system disorder was associated, this prevalence was more distinct. With semiquantitative measurements of the surface of polyglucosan bodies a significant correlation was found between age and percentage of large bodies.

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Lafora disease is an autosomal recessive and progressive degenerative disorder of the central nervous system (CNS). The pathogenic mechanism has been presumed to be an inborn error of carbohydrate metabolism, although this has never been proved. In a case of proven Lafora disease, pyruvate metabolism, which has a central position in carbohydrate metabolism, was studied in body fluids under various conditions and in brain biopsy material. No abnormalities in this metabolic pathway were found. This finding plus earlier reports in the literature exclude a defect in glycolysis; thus, a disturbance of carbohydrate metabolism as the pathogenic mechanism of Lafora disease is unlikely.

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The presence of polyglucosan bodies was studied in intramuscular motor nerves of 292 muscle biopsies. These biopsies were classified into five diagnostic categories and investigated for the presence of polyglucosan bodies in relation to age and sex. Their presence was nonspecific in patients over 20 years, the only correlation being with ageing. Under 20 years, their presence pointed to the diagnosis of Lafora's disease. In cases in which both a muscle biopsy and a sural nerve biopsy were performed, the former appeared to contain these polyglucosans more frequently.

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Skin biopsies from the axilla were examined in 7 patients with clinical signs and symptoms of Lafora's disease, in 9 relatives (7 parents and 2 siblings), and in 17 patients with chronic or progressive degenerative neurological disorders and chronic epilepsy, who served as controls. In the biopsies of all patients with Lafora's disease, typical periodic acid-Schiff (PAS)-positive inclusions were present in the myoepithelial cells of the secretory acini of the apocrine glands and/or in the cells of the eccrine duct. No abnormalities were found in the biopsies from relatives and controls. We conclude that axilla skin biopsy is an easy and reliable test for diagnosing Lafora's disease, and is preferable to liver biopsy, but has no value for carrier detection.

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Morphological and biochemical studies were performed on a brain biopsy from a patient with typical Lafora disease. Qualitative morphological investigation of the cortex showed that the Lafora bodies were most abundant in layers III and V of the cerebral cortex. They were exclusively located in the neurons and their processes. Quantitative morphological investigation of the cerebral cortex revealed abnormalities of the pyramidal cells of layers III and V. The neurons were often slightly atrophic. There was a reduction in the number of dendrites, in maximal dendritic length, and in the number of spines on the apical dendrites and on the side branches. Because of the biochemical study of the pyruvate metabolism of the gray and white matter of the cortex did not show abnormalities, a mitochondrial dysfunction is not likely.

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A case of an 11-year-old boy with an autosomal dominant form of paroxysmal kinesigenic choreoathetosis is presented. Routine EEG, sleep EEG recording, and registration of visual evoked potentials and somatosensory evoked potentials were normal. EEG with videomonitoring and registration of event-related potentials, however, showed abnormalities, which are discussed in detail. Our data provide further arguments in support of the hypothesis that paroxysmal kinesigenic choreoathetosis is the expression of a dysbalance in the cortico-striopallidal-thalamic loop, and has an extrapyramidal genesis.

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