Caseating hepatic granulomas in Hodgkin's lymphoma.

A 68-year-old man presented with recurrent Hodgkin's lymphoma after a 9-year disease-free interval induced by chemotherapy. In addition to histological evidence of recurrent Hodgkin's disease, the liver biopsy specimen showed extensive caseating granulomas. Cultures of bone marrow and liver tissue tested negative for Mycobacterium tuberculosis.

Refined crystal structure of the phosphorylase-heptulose 2-phosphate-oligosaccharide-AMP complex.

The crystal structure of phosphorylase b-heptulose 2-phosphate complex with oligosaccharide and AMP bound has been refined by molecular dynamics and crystallographic least-squares with the program XPLOR. Shifts in atomic positions of up to 4 A from the native enzyme structure were correctly determined by the program without manual intervention. The final crystallographic R value for data between 8 and 2.

Isolated inferior oblique paresis from brain-stem infarction. Perspective on oculomotor fascicular organization in the ventral midbrain tegmentum.

We present the case of an isolated inferior oblique muscle paresis from ventral midbrain infarction involving the oculomotor fascicular fibers. Based on this case and a review of the literature, the anatomic organization of the oculomotor nerve fascicles and of the pupillary fibers in the ventral midbrain tegmentum is proposed.

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.

The allosteric transition of glycogen phosphorylase.

The crystal structure of R-state glycogen phosphorylase b has been determined at 2.9 A resolution. A comparison of T-state and R-state structures of the enzyme explains its cooperative behaviour on ligand binding and the allosteric regulation of its activity.

Surface quality of gypsums when poured against alginates.

Alginate impression materials are universally accepted for the fabrication of dental casts. Since casts reflect a direct link between the patient and the dentist, it is imperative that their surfaces be of highest quality. This study assesses the quality of dental cast surfaces when poured against alginate impression materials.

Corectopia and lipoid proteinosis.

Lipoid proteinosis (Urbach-Wiethe disease) is a rare autosomal recessive disorder associated with deposition of hyalinised material in the skin, mucous membrane, and brain. Corectopia has not been described in this disorder. A case is presented of lipoid proteinosis with bilateral corectopia.

The binding of beta-glycerophosphate to glycogen phosphorylase b in the crystal.

The binding of beta-glycerophosphate (glycerol-2-P) to glycogen phosphorylase b in the crystal has been studied by X-ray diffraction at 3 A resolution. Glycerol-2-P binds to the allosteric effector site in a position close to that of AMP, glucose-6-P, UDP-Glc, and phosphate. In this position, glycerol-2-P is stabilized through interactions of its phosphate moiety with the guanidinium groups of Arg 309 and Arg 310 which undergo conformational changes, and the hydroxyl group of Tyr 75, while the same residues and solvent are involved in van der Waals interactions with the remaining part of the molecule.

An in vitro investigation of lingual bonding.

An in vitro investigation was undertaken to evaluate the bonding of orthodontic appliances onto lingual surfaces; 53 maxillary premolars, 37 mandibular premolars, and 37 mandibular incisors were used. Brackets were bonded onto the lingual and labial surfaces and fractured with an Instron machine. Enamel damage associated with debonding also was assessed.

Isolated cyclovertical muscle palsy: a simplified algorithm for interpreting the three-step test.

A simplified algorithm is presented for determining the palsied cyclovertical muscle, once the three-step test is completed. The examiner is required only to remember the three-step test characteristics of two muscles (right superior oblique, left inferior oblique) and the Knight's move in chess.

Relative scotoma and statokinetic dissociation (Riddoch's phenomenon) from occipital lobe dysfunction.

Riddoch's phenomenon, in which a stimulus is perceived during movement but not with static presentation, has been reported for occipital lobe and anterior visual pathway disorders. To our knowledge, a threshold for movement detection in the affected hemifield has not been reported. A case of statokinetic dissociation from occipital lobe infarction is presented in which a threshold range for movement detection was identified.

Correlation of afferent pupillary defect with visual field loss on automated perimetry.

The study was designed to ascertain the relationship between visual loss in the central 30 degrees of vision and the density of the relative afferent pupillary defect (APD). The APD of 26 patients was quantified using a neutral log density filter. The mean threshold light sensitivity on Humphrey automated perimetry (Program 30-1) of one eye was substracted from the fellow eye total to yield the interocular visual field difference (VFD).

Structural changes in glycogen phosphorylase induced by phosphorylation.

A comparison of the refined crystal structures of dimeric glycogen phosphorylase b and a reveals structural changes that represent the first step in the activation of the enzyme. On phosphorylation of serine-14, the N-terminus of each subunit assumes an ordered helical conformation and binds to the surface of the dimer. The consequent structural changes at the N- and C-terminal regions lead to strengthened interactions between subunits and alter the binding sites for allosteric effectors and substrates.

Channels at the catalytic site of glycogen phosphorylase b: binding and kinetic studies with the beta-glycosidase inhibitor D-gluconohydroximo-1,5-lactone N-phenylurethane.

Regions of low packing density in the vicinity of the catalytic site of glycogen phosphorylase b are described with the aid of a computer program that generates a contour map in which the contour level is inversely proportional to the packing density in the protein. It is shown that, although there is no direct route from the catalytic site to the surface, there are two possible channels that could allow access for substrates following conformational changes in the enzyme. The first channel, channel 1, leads from the catalytic site to the surface close to the nucleoside inhibitor site and requires movements of residues 280-285 and Arg 569 in order to obtain access.