Assessment of contrast gain signature in inferred magnocellular and parvocellular pathways in patients with glaucoma.

Purpose: Contrast gain signatures of inferred magnocellular and parvocellular postreceptoral pathways were assessed for patients with glaucoma using a contrast discrimination paradigm developed by Pokorny and Smith. The potential causes for changes in contrast gain signature were investigated using model simulations of ganglion cell contrast responses.

Methods: Foveal contrast discrimination thresholds were measured with a pedestal-Delta-pedestal paradigm developed by Pokorny and Smith [Pokorny, J.

Virus particle core defects caused by mutations in the human immunodeficiency virus capsid N-terminal domain.

The N-terminal domains (NTDs) of the human immunodeficiency virus type 1 (HIV-1) capsid (CA) protein have been modeled to form hexamer rings in the mature cores of virions. In vitro, hexamer ring units organize into either tubes or spheres, in a pH-dependent fashion. To probe factors which might govern hexamer assembly preferences in vivo, we examined the effects of mutations at CA histidine residue 84 (H84), modeled at the outer edges of NTD hexamers, as well as a nearby histidine (H87) in the cyclophilin A (CypA) binding loop.

Analysis of the retrovirus capsid interdomain linker region.

In structural studies, the retrovirus capsid interdomain linker region has been shown as a flexible connector between the CA N-terminal domain and its C-terminal domain. To analyze the function of the linker region, we have examined the effects of three Moloney murine leukemia virus (M-MuLV) capsid linker mutations/variations in vivo, in the context of the full-length M-MuLV structural precursor protein (PrGag). Two mutations, A1SP and A5SP, respectively, inserted three and seven additional codons within the linker region to test the effects of increased linker lengths.

Retrovirus capsid protein assembly arrangements.

During retrovirus particle assembly and morphogenesis, the retrovirus structural (Gag) proteins organize into two different arrangements: an immature form assembled by precursor Gag (PrGag) proteins; and a mature form, composed of proteins processed from PrGag. Central to both Gag protein arrangements is the capsid (CA) protein, a domain of PrGag, which is cleaved from the precursor to yield a mature Gag protein composed of an N-terminal domain (NTD), a flexible linker region, and a C-terminal domain (CTD). Because Gag interactions have proven difficult to examine in virions, a number of investigations have focused on the analysis of structures assembled in vitro.

Hantavirus nucleocapsid protein oligomerization.

Hantaviruses are enveloped, negative-strand RNA viruses which can be lethal to humans, causing either a hemorrhagic fever with renal syndrome or a hantaviral pulmonary syndrome. The viral genomes consist of three RNA segments: the L segment encodes the viral polymerase, the M segment encodes the viral surface glycoproteins G1 and G2, and the S segment encodes the nucleocapsid (N) protein. The N protein is a 420- to 430-residue, 50-kDa protein which appears to direct hantavirus assembly, although mechanisms of N protein oligomerization, RNA encapsidation, budding, and release are poorly understood.

Positron emission tomography studies of healthy volunteers--no effects on the dopamine terminals and synthesis after short-term exposure to toluene.

Despite extensive research, the mechanisms for the effects of organic solvents on the central nervous system are still unknown. One mechanism proposed is that solvents interfere with the synthesis of neurotransmitters. In the present study 11 male healthy volunteers were exposed during 15 min to 100 p.

Do organic solvents induce changes in the dopaminergic system? Positron emission tomography studies of occupationally exposed subjects.

Objectives: The objective of this study was to test the hypothesis that long-term occupational exposure to organic solvents may effect the levels and turnover of dopamine in man.

Methods: A study was performed on 17 patients with neuropsychiatric symptoms due to occupational solvent exposure, and 11 healthy non-exposed male volunteers (controls). Positron emission tomography (PET) was used to assess striatal dopaminergic function, using L-[11C]DOPA, [11C]nomifensine and [11C]raclopride as tracers.

Mercury deposits in neurons of the trigeminal ganglia after insertion of dental amalgam in rats.

An amalgam filling was inserted into the first upper molar of 12 rats and the animals were killed after 3-9 months. Tissue sections from the trigeminal ganglia and the brain stem were then investigated with a sensitive histochemical technique to trace mercury deposits. Within the trigeminal ganglia, nerve cells with mercury deposits were observed in seven out of 12 rats, whereas no mercury was detected in sections from the brain stem.

A review of axonal transport of metals.

Neurons have efficient mechanisms for the transport of organelles and chemical substances in axons to the nerve terminals and back to the cell bodies. Enzymes involved in transmitter synthesis, peptide transmitters and their precursors are examples of macromolecules that are transported down the axon, anterogradely. For final degradation and possible reuse, many constituents are transported back to the cell body, retrogradely.

Inorganic mercury is transported from muscular nerve terminals to spinal and brainstem motoneurons.

The distribution of mercury within the brainstem and spinal cord of mice was investigated with the autometallographic technique after intramuscular administration of a single dose of mercuric mercury (HgCl2). Deposits of mercury were localized to motor neurons of the spinal cord and to brainstem motor nuclei; i.e.

Accumulation of inorganic mercury in lower motoneurons of mice.

The distribution of mercury within the lower brain stem and spinal cord of mice was investigated at various intervals after a single intramuscular injection of mercuric chloride. The autometallographic technique was used to demonstrate the presence of mercury deposits in tissue sections. Accumulation of mercury was observed in motoneurons of the anterior horns and in motor nuclei of the brainstem.

Accumulation of mercury in brainstem nuclei of mice after retrograde axonal transport.

Adult mice were injected intramuscularly in the region of the vibrissae muscles on the left side of the nose with a small volume of mercuric chloride dissolved in distilled water. The animals were killed after 1-6 weeks and fixed by whole-body perfusion. Frozen sections were taken from different levels of the brain stem and from the kidney.

Retrograde axonal transport of mercury in primary sensory neurons innervating the tooth pulp in the rat.

The pulp cavity of the first upper molar was exposed unilaterally in adult rats with a dental drill and about 1 microliter of mercuric chloride was injected into the coronal pulp. The rats were killed after 1-24 days and frozen sections from the trigeminal ganglia were subjected to silver acetate autometallography for demonstration of mercury. Mercury was found to have accumulated in neurons of the ipsilateral trigeminal ganglion by retrograde axonal transport.

Retrograde axonal transport of mercury.

Female Wistar rats were injected in the tongue with a small volume of 203Hg and were killed 2 weeks later. The lower brain stem with the hypoglossal nuclei was removed and sectioned in a cryostat. Autoradiography of freeze-dried sections showed labeling of both hypoglossal nuclei.

Distribution of 109Cd in the nervous system of rats after intravenous injection.

The distribution of i.v. injected 109Cd within the nervous system was studied in rats 24 h and 1 week after the injection.

Autoradiographic localization of cadmium in the rat brain.

Adult rats were injected intravenously with 109CdCl2 and the distribution of the isotope within the brain and neighboring nervous structures was subsequently studied by autoradiography. Cadmium accumulated in regions outside the blood-brain barrier such as the choroid plexus, pineal gland and area postrema, but did not appear in the brain parenchyma. Uptake of cadmium was observed in the trigeminal ganglia close to the nerve cells and in the olfactory bulbs.

Retrograde axonal transport of cadmium in the rat hypoglossal nerve.

A small volume of radioactively labelled cadmium was injected into the tongue of rats. Two weeks later, the rats were killed and the lower brainstem with the hypoglossal nuclei was dissected out and sectioned in a cryostat. Autoradiography of freeze-dried sections showed accumulation of cadmium in both hypoglossal nuclei.

Distribution of 109Cd in the nervous system of rats after intravenous injection.

The distribution of intravenously injected 109Cd in the nervous system was studied in rats twenty-four hr and one week after the injection. Measurements by gamma scintillation showed a high uptake of cadmium in peripheral sensory and autonomic ganglia whereas the uptake was low in the brain, cerebellum and spinal cord. The accumulation of cadmium in the sciatic nerve was significantly higher than in the brain and spinal nerve roots but lower than in ganglia.

Oro-facio-digital syndromes I and II: radiological methods for diagnosis and the clinical variations.

In view of the different modes of inheritance and the different prognoses of the two oro-facio-digital syndromes, type 1 (OFD-I) and type 2 (OFD-II), it is important to establish a correct diagnosis in these patients. In this report two new patients with the OFD-I syndrome are presented. One of them (Case 1) had multiple congenital malformations and never made any mental contact.

Evidence for vesicular transport of horseradish peroxidase across endoneurial vessels of the sciatic nerve in normal mice.

The permeability of the endoneurial blood vessels of the sciatic nerve to horseradish peroxidase (HRP) was investigated in mice. The animals were killed 2,5, or 30 min after an i.v.

Influence of age on the development of cadmium-induced vascular lesions in rat sensory ganglia.

It is known from previous investigations that parenteral administration of single large doses of cadmium salts causes hemorrhagic lesions in the sensory ganglia of adult rats, whereas the ganglia of immature rats remain unaffected. The present study was undertaken to determine more precisely the age at which vascular lesions occur in the sensory ganglia of rats. At the age of 10 days, thrombocytes accumulated and adhered to the endothelial cells in vessels of the trigeminal ganglion, and at the age of 12 days focal hemorrhages occurred in the vicinity of nerve cells.

Cytofluorescence localization of adriamycin in the nervous system. I. Distribution of the drug in the central nervous system of normal adult mice after intravenous injection.

By a fluorescence-microscopic technique the distribution of the antineoplastic glycoside, adriamycin (doxorubicin), was studied in the CNS of normal adult mice after i.v. injection.

Cytofluorescence localization of adriamycin in the nervous system. II. Distribution of the drug in the somatic and autonomic peripheral nervous systems of normal adult mice after intravenous injection.

By a fluorescence-microscopic technique, the distribution of the antineoplastic glycoside adriamycin (doxorubicin) was studied in the peripheral nervous system (PNS) of normal adult mice after i.v. injection.