ABSTRACT
The ref(2)P gene is involved in the control of sigma rhabdovirus multiplication in Drosophila melanogaster. ref(2)P activity is also necessary for male fertility. However, in one-third of laboratory strains tested, males that lacked ref(2)P activity were fertile. In all such strains studied, the male sterility phenotype was abolished due to the presence of a particular allele at the Su(P) locus, at 73B1-2. These spontaneous suppressor alleles were dominant. We were able to induce dominant suppressor alleles at the Su(P) locus by X-ray mutagenesis and hybrid dysgenesis, suggesting that null alleles of Su(P) confer the dominant suppressor phenotype. The Su(P) gene was cloned by P element tagging. The P element-tagged alleles identified a Su(P) transcript as a 1.4-kb mRNA produced in the soma of both males and females, which is also abundant in ovaries.
Subject(s)
Drosophila Proteins , Drosophila melanogaster/genetics , Fertility/physiology , Genes, Insect/physiology , Insect Proteins/genetics , Membrane Proteins , Nerve Tissue Proteins/genetics , Nuclear Proteins , Alleles , Animals , Animals, Genetically Modified , Base Sequence , Chromosome Mapping , Cloning, Molecular , DNA Transposable Elements , DNA, Complementary , DNA-Binding Proteins , Female , Male , Molecular Sequence Data , RNA , Synaptosomal-Associated Protein 25ABSTRACT
4 patients with prosopagnosia are described. They presented associated neuropsychological deficits (achromatopsia, topographical disorientation) and visual field defects. In 1 case, gross pathological examination revealed bilateral symmetrical infero-medial occipito-temporal infarcts. In 2 other cases, computer tomography (CT) demonstrated bilateral inferior temporo-occipital infarction. In 1 case CT showed only occipital infarctions in the occipital lobes. This brings to 16 the number of anatomically studied cases of prosopagnosia (8 by necropsy, 8 by CT). In contrast to clinical localization, which often indicates only a right cerebral lesion, all anatomically verified cases of prosopagnosia exhibit bilateral lesions in the posterior cerebral artery distribution.
Subject(s)
Agnosia/diagnosis , Visual Perception , Adult , Aged , Apraxias/diagnosis , Cerebral Infarction/diagnosis , Discrimination Learning , Electroencephalography , Humans , Intracranial Arteriosclerosis/diagnosis , Male , Middle Aged , Orientation , Pattern Recognition, Visual , Psychological Tests , Tomography, X-Ray Computed , Visual FieldsABSTRACT
The effects of acrylamide intoxication were studied both in peripheral (PNS) and central (CNS) nervous system of rats. The animals were sacrified at different time intervals from the beginning of the intoxication. Histological and ultrastructural studies of peripheral nerves and long tracts of the spinal cord revealed a severe axonopathy, characterized by swelling of axons, particularly in the paranodal regions due to accumulation of neurofilaments with almost complete disappearance of neurotubules. There was also aggregation of dense bodies, swollen mitochondria and multivescicolar bodies in subaxolemmal regions. Presynaptic endings in the anterior horns of the spinal cord and in the cuneate nuclei were swollen and filled with packed filaments. Fiber degeneration at different stages was seen both in PNS and in CNS. These changes are not specific for acrylamide intoxication, having been observed in other experimentally induced neuropathies (n-hexane, Mn-BK, CS2, ...), as well as in a variety of diseases both genetically determined and due to exposure to toxic substances (glue-sniffing, leather cement poisoning, antiblastic therapy, ...). Accumulation of filaments in peripheral and central axons is the pattern of fiber degeneration characterizing the dying-back neuropathies. These axonal changes are particularly marked in the pacinian bodies as well as in the distal segments of the fibres. These data support the hypothesis that a dying-back neuropathy might depend on the direct effect of the toxic substance on the most vulnerable segments of the fibres, rather than on the perikaryon of the nerve cell, as previously supposed.
Subject(s)
Acrylamides/poisoning , Central Nervous System Diseases/chemically induced , Peripheral Nervous System Diseases/chemically induced , Animals , Central Nervous System Diseases/pathology , Peripheral Nerves/pathology , Peripheral Nervous System Diseases/pathology , Rats , Spinal Cord/pathologyABSTRACT
The peripheral nerve biopsy specimens of 4 cases of toxic polyneruopathies induced by exposure to leather cement in shoe industries were studied. Analysis of the cements used in the manufacturing process proved them to contain n-hexane as a volatile substance. Light- and electron-microscopic examination of nerve biopsies showed segmental swelling of axons due to the accumulation of packed filaments and thinning of the overlying myelin sheath. Neither active nerve fibre degeneration nor regeneration were frequently seen. It has been suggested that features of so-called giant axonal neuropathy are the most common pattern of peripheral nerve degeneration in chronic n-hexane intoxication.
Subject(s)
Occupational Diseases/chemically induced , Polyneuropathies/chemically induced , Shoes , Adolescent , Axons/ultrastructure , Female , Humans , Inclusion Bodies/ultrastructure , Italy , Myelin Sheath/ultrastructure , Occupational Diseases/pathology , Peroneal Nerve/ultrastructure , Polyneuropathies/pathology , Sural Nerve/ultrastructure , SyndromeABSTRACT
The purpose of this paper is to propose a preliminary scheme which standardizes the terminology and the manner of classifying comatose states due to organic cerebral lesions. This attempt is based on recognition of the need to use a common language in order to facilitate the transmission of information in this field.
