Papilledema: clinical clues and differential diagnosis.

The term "papilledema" describes optic disc swelling resulting from increased intracranial pressure. A complete history and direct funduscopic examination of the optic nerve head and adjacent vessels are necessary to differentiate papilledema from optic disc swelling due to other conditions. Signs of optic disc swelling include elevation and blurring of the disc and its margins, venous congestion, and retinal hard exudates, splinter hemorrhages and infarcts.

A regular pattern of two types of 100-residue motif in the sequence of titin.

Titin is the largest polypeptide yet described (relative molecular mass approximately 3 x 10(6); refs 1, 2) and an abundant protein of striated muscle. Its molecules are string-like and in vivo span from the M to Z-lines. I-band regions of titin are thought to make elastic connections between the thick filament and the Z-line, thereby forming a third type of sarcomere filament.

Cranial nerve paresis following epidural and spinal anesthesia.

Three cases of cranial nerve paresis following epidural and spinal anesthesia are presented. One patient had combined oculomotor and abducens nerve paresis, while the other two patients had solitary abducens nerve pareses. The authors postulate that mechanical traction is the cause of cranial nerve paresis following epidural and spinal anesthesia.

Computed tomographic features of nonthyroid extraocular muscle enlargement.

While Graves' disease is the most common cause of enlarged extraocular muscles, other disorders may masquerade as dysthyroid orbitopathy. The authors conducted a retrospective analysis of the computed tomographic (CT) scans of 60 patients with nonthyroid enlarged extraocular muscles to establish the differential radiographic features of these disorders. The diseases were classified as primary or local invasion of neoplasm (26%), inflammatory (25%), metastatic tumor (20%), vascular (13%), infection (12%), and acromegaly (3%).

Does titin regulate the length of muscle thick filaments?

The protein titin has been localized by electron microscopy of myofibrils labelled with monoclonal antibodies. The data are consistent with individual titin molecules extending from near the M-line to beyond the ends of thick filaments, a distance of approximately 1 micron. In the A-band, titin appears to be bound to thick filaments, probably to the outside of the filament shaft.

Degradation of myofibrils from rabbit, chicken and beef by cathepsin l and lysosomal lysates.

The degradation of rabbit, chicken and beef myofibrils by cathepsin L or lysosomal lysates was studied by SDS-polyacrylamide-gel electrophoresis and electron microscopy (EM). Similar degradation patterns were observed for each myofibrillar preparation incubated with cathepsin L, except that myosin heavy chain and tropomyosin of beef were more susceptible than those of rabbit and chicken. Otherwise, troponin T, troponin in I and C-protein were rapidly degraded with slower degradation of titin, nebulin, myosin heavy chain, α-actinin, α-tropomyosin, actin and myosin light chains, LC1 and LC2.

Purification and properties of native titin.

A procedure has been developed for the extraction and purification of the massive myofibrillar protein titin without exposing it to denaturing conditions. The form of the molecule that has been isolated is soluble at high ionic strength and alkaline pH, but precipitates in low salt or at pH values below 7. Sedimentation velocity experiments indicate that titin is a highly asymmetric molecule with a sedimentation coefficient of 13.

Immunological studies with human aortic elastin.

Antibodies to human fetal aortic elastin were isolated from sheep immunized with alpha-elastin peptides. In preliminary tests of specificity using passive hemagglutination, partial cross-reactivity was demonstrated with alpha-elastin from other species. However, in a double antibody radio-immunoassay alpha-elastin peptides from other mammalian species failed to compete with 125I-labelled human alpha elastin.

Molecular weights and Stokes radii of soluble elastins.

Soluble elastin was isolated from lathyritic chick aorta using neutral salt solutions in the presence of beta-amino propionitrile. The effect of a carboxy-methylation step in conjunction with proteolytic inhibitors was investigated. Hydrodynamic (Stokes) radii of soluble elastins were measured by gel filtration and the molecular size and weight distribution in purified fractions are reported.

The coacervate-sol transition observed with alpha-elastin and its N-formyl O-methyl derivative.

The coacervate phase produced by raising the temperature of solutions of blocked alpha-elastin has water content and fibrillar structure at electron microscope level similar to fibrous elastin (Cox, B.A., Starcher, B.

Isolation of salt-soluble elastin from ligamentum nuchae of copper-deficient calf.

This paper describes the isolation and amino acid analysis of un-cross-linked elastin obtained by neutral salt extraction from the ligamentum nuchae of a calf fed from birth to 9 months on a diet low in copper.

Biological responses of Habrobracon to spaceflight.

Since the interaction of the parasitic wasp Habrobracon with the space environment could not be prejudged, we decided to test approximately 30 different parameters of a genetic, mutational, biochemical, behavioral, and physiological character in the one spaceflight we had at our disposal. These parameters were examined at six different exposures of gamma-radiation (including 0 dose) in flight, resulting in about 180 different endpoints in all. The most profound effects of spaceflight in conjunction with radiation were decreased hatchability and enhanced fecundity of eggs exposed to spaceflight at different stages of oogenesis.

Mutational responses of insects in the Biosatellite II experiment.

Genetic effects associated with space flight include mutation induction by the space flight itself, and enhancements or antagonisms of radiation-induced mutations. The conditions of space flight vary in mutagenic effectiveness from no response at all to responses nine times that found in ground-based controls. The test systems follow the sensitivity pattern: spermatogonial translocations > oogonial and oocyte nondisjunction > recessive lethality of stages in spermatogenesis > dominant lethality of stages in spermatogenesis.