Proximal forearm ulnar nerve conduction techniques.

Compression of the ulnar nerve across the elbow is a common clinical diagnosis frequently referred for electrodiagnostic evaluation. Motor conduction studies with recording over the abductor digiti minimi and stimulating proximal and distal to the ulnar notch have been the standard technique employed in these evaluations--mean, 60.0 m/s; SD 5.0 m/s. Two other techniques are described, with data from normal subjects, recording from proximal forearm muscles. One technique is a refinement of a previously described method recording from the flexor carpi ulnaris--mean, 63.0 m/s; SD, 4.7 m/s. The second is a newly developed technique recording from the flexor digitorum profundus--mean, 63.0 m/s; SD, 5.5m/s. All three methods were found to have a small range of comparable normal values, and appear to be easily and quickly performed with reliable and reproducible information. The techniques described enhance specific localization of ulnar nerve lesions, and may prove useful when more distal recording sites are unavailable.

Relationship of molecular structure to in vivo scintigraphic distribution patterns of carbon-11 labeled compounds. 3. (11C)Hydantoins.

The preparation and gamma-scintigraphic evaluation of the in vivo distribution patterns in dogs of a series of structurally related hydantoins labeled with the positron emitting, 20.4 min half-life radionuclide, carbon-11 are described. Carbon-11 labeled HCN was collected in water or aqueous Me2SO containing carrier KCN following cyclotron bombardment of 99% N2-1% H2 gas mixture with 22 MeV protons for 1 hr at 25-35 muA. Five 11C-labeled 5,5-dialkylhydantoins, three [11C]diarylhydantoins, five [11C]-5-alkyl-5-phenylhydantoins, and five [11C]spirohydantoins were prepared by heating generally under pressure, a mixture of 11C-labeled KCN, which was produced by isotopic exchange with carrier KCN, the corresponding aldehyde or ketone, and excess (NH4)2CO3 in aqueous ethanol or Me2SO solvent. The 11C-labeled hydantoins were dissolved in 1-1.5% aqueous NaOH for intravenous administration to dogs. Total synthesis time was 70-106 min and 1-59 mCi of final product was available for conducting serial in vivo imaging for up to 2 hr or more with the gamma-scintillation camera. Carbon-11 activity from all compounds showed initial blood-pool distribution with variable concentration of activity in the brain, lungs, liver, and kidney. All of the 11C-labeled diarylhydantoins, and most having one phenyl substituent, and one having a hexamethylene moiety showed initial accumulation of 11C activity in brain. Carbon-11 labeled 5,5-diphenylhydantoin (dilantin) showed the greastest qualitative accumulation of activity in the brain. Those 11C-labeled hydantoins having a carboxyl substituent showed prominent renal concentration and urinary excretion of activity. Most 11-c-labeled hydantoins showed a progressive homogenous whole body distribution of activity in all cellular tissues of the body. The relatively uniform distribution of activity in cellular tissues and slow excretion from the body support the thesis that the pharmacologic action of the hydantoins is related to physical effects on biomembranes rather than to specific chemical interactions with cell constituents.