A clinicopathologic study of optic neuropathies associated with intracranial mass lesions with quantification of remaining axons.

We examined three patients with intracranial mass lesions that damaged the anterior visual pathway and studied this damage histologically after the patients died. Estimation of the number of surviving axons in the six optic nerves generally showed the greatest atrophy to be in the temporal sector in cross sections immediately behind the globe. More posterior to the globe, atrophy appeared greatest in the center of several nerves.

Branch artery occlusion. An unusual complication of external carotid embolization.

A case of retinal branch artery occlusion was caused by migration of emboli, presumably via collateral circulation, during therapeutic embolization of the maxillary artery. Migration of particles to the ophthalmic circulation is unusual with embolization of the branches of the external carotid artery. Meticulous technique, careful angiographic monitoring, and proper selection of embolic material may reduce, but not eliminate, migration of emboli to undesirable locations.

Developmentally regulated nonhistone proteins: evidence for deoxyribonucleic acid binding role and localization near deoxyribonuclease I sensitive domains of precartilage cell chromatin.

Differentiation of cartilage from precartilage mesenchyme in the chick embryo is accompanied by the loss of two abundant nonhistone proteins (Mr 35 500 and 125 000) termed PCP 35.5 and PCP 125. Here we examine the distribution of these and other developmentally regulated nonhistones in nuclease-sensitive regions of precartilage and cartilage chromatin.

Visual following during stimulation of an immobile eye (the open loop condition).

We had the rare opportunity to examine a patient with a unilateral complete ophthalmoplegia in an eye with normal visual acuity. We recorded the movements of the covered, sound eye of the patient during full-field optokinetic stimulation of his seeing, immobile eye (open loop condition). The open loop gain for low velocity stimuli (less than 1 deg/sec) was high (greater than 50) but progressively fell with faster stimuli.

The distal boundary of myogenic primordia in chimeric avian limb buds and its relation to an accessible population of cartilage progenitor cells.

Using chimeras consisting of chick embryos that had received substitution grafts of quail somites, we have determined the distalmost extension of the myogenic primordia in the outgrowing wing bud at 5 days of incubation. At Hamburger-Hamilton stage 25 the most distal premuscle cell is consistently 300 mum or more from the apex of the wing mesoblast. The stage 25 wing tip resembles very early whole limb buds in not having proceeded beyond the mesenchymal state or having expressed markers of terminal differentiation.

Talpid2 mutant of the chicken with perturbed cartilage development has an altered precartilage-specific chromatin protein.

An abundant nonhistone protein (Mr, 125,000) is lost from the chromatin embryonic chicken precartilage mesenchyme cells as they differentiate into cartilage [Newman, SA., Birnbaum, J & Yeoh, G.C.

Accommodation defect in Wilson's disease.

A 22-year-old man with Wilson's disease had blurred vision caused by a defect of accommodation that we believed to be supranuclear in origin.

Fibroblast progenitor cells of the embryonic chick limb.

A population of mesenchymal cells derived from the stage-25 chick wing tip gives rise to progeny of a similar morphology and to authentic fibroblasts when grown in low density culture. Mixed clones containing both cell types are often observed. As the more rapidly proliferating fibroblasts begin to predominate in these cultures, collagen biosynthesis rises from the basal mesenchymal level to a level characteristic of mature fibroblasts.

Dynamics of skeletal pattern formation in developing chick limb.

During development of the embryonic chick limb the skeletal pattern is laid out as cartilaginous primordia, which emerge in a proximodistal sequence over a period of 4 days. The differentiation of cartilage is preceded by changes in cellular contacts at specific locations in the precartilage mesenchyme. Under realistic assumptions, the biosynthesis and diffusion through the extracellular matrix of a cell surface protein, such as fibronectin, will lead to spatial patterns of this molecule that could be the basis of the emergent primordia.

Urea-induced binding of histone 1 to nucleosomes lacking linker DNA.

The binding of H1 (and H5) to nucleosome core particles was demonstrated by separating mononucleosomes according to their DNA size on acrylamide gels containing high molarity urea. The presence of urea causes a redistribution of H1 so that it associates with some particles of all linker lengths, including no linker. When the urea is removed the H1 remains associated with particles of all DNA sizes if the different size classes are not mixed with each other.

Molecular weight and valence of the cell-surface receptor for immunoglobulin E.

The molecular weight of the active solubilized cell-surface receptor for immunoglobulin E (IgE) was measured in nonionic detergent. The diffusion coefficient was estimated by gel filtration, the partial specific volume was estimated from the differential sedimentation in sucrose gradients prepared from H2O and D2O, and the sedimentation constant was estimated from the same centrifugation experiments. The receptor has an apparent molecular weight of 130,000.

Assay and partial characterization of the solubilized cell surface receptor for immunoglobulin E.

The cell surface component (receptor) which specifically binds immunoglobulin E (IgE) presumably forms an integral part of the functional chain involved in the antigen-induced IgE-mediated degranulation of histamine-containing mast cells and basophils. This paper describes a simple (NH4)2SO4 predipitation assay with which the interaction of IgE with detergent-solubilized receptors can be reproducibly quantitated. Receptor saturation was demonstrated and a linear response to receptor concentration over at least a 30-fold rang obtained.

Model for constraint and control in biochemical networks.

A model is proposed for biochemical networks which takes into account substrate and modifier effects on enzyme activity and the different time scales on which the relevant processes occur. Sources of global constraint that can be utilized in metabolic regulation are indicated, and the relation of the model to the experiments of Kauffman on switching networks is analyzed. The biological significance of the model and possible systems in which it might be tested are discussed.