Isolation and characterization of the mouse cytosolic phosphoenolpyruvate carboxykinase (GTP) gene: evidence for tissue-specific hypersensitive sites.

A 72 kilobase pair DNA fragment that contains the mouse phosphoenolpyruvate carboxykinase (PEPCK) gene locus, pck1, was isolated from a genomic bacterial artificial chromosome library. The region from approximately -5.5 to +6.6 kilobase pairs relative to the pck1 transcription start site was sequenced and exhibits a high degree of homology to the rat and human genes. Additionally, the chromatin structure of the PEPCK gene in mouse liver resembles that seen in rat. Backcross panel analysis of a microsatellite sequence confirms that the gene is located on chromosome 2. Hypersensitive site analysis was performed on nuclei isolated from the adipocyte cell line 3T3-F442A in the preadipose and adipose states. Several hypersensitive sites are present in the undifferentiated 3T3-F442A cells, before PEPCK mRNA is detected. The same sites are present after differentiation, however, the sensitivity of mHS 3 increases relative to the others. We conclude that the chromatin is open in 3T3-F442A cells and that factors are able to bind in the undifferentiated state but that something else is required for transcription.

Incurvated nail. Does the phalanx determine nail plate shape?

This study examines the relationship between the shape of the nail plate of the hallux and the base of its distal phalanx. Twenty-three cadaver specimens were examined anatomically for nine variables. These variables represented the following: height and width of the distal phalanx base; height and width of the proximal aspect of the nail plate; distal shape of the nail plate; ratio of the nail plate height and width and structural index of the nail plate. Statistics for the variables are presented using correlation coefficients between nail structural index and bone structural index. The study shows a high and significant correlation between the shape of the proximal aspect of the nail plate and that of the phalangeal base.

Penicillin resensitization among hospitalized patients.

The purpose of this study was to determine the frequency of resensitization to penicillin after oral or intravenous treatment with beta-lactam antibiotics in hospitalized patients with histories of penicillin allergy. Seventeen adults (aged 24 to 76 years) and one child (aged 10 years) were treated intravenously and/or orally with beta-lactam antibiotics after negative skin tests were obtained with benzylpenicilloyl polylysine, potassium penicillin G, and alkaline hydrolysis products of penicillin G as minor determinant mixture. Repeat skin testing was performed 1 to 12 months after the therapy. Three patients (16%) became skin test positive after the treatment. Two patients reacted to potassium penicillin G alone, and the other patient reacted to benzylpenicilloyl polylysine and minor determinant mixture. These three patients were among the 15 patients who were treated with intravenous antibiotics. This study reveals a high percentage of skin test conversion after intravenously administered penicillin therapy and confirms the present practice of advising patients with a history of penicillin allergy who have successfully completed penicillin treatment to have a repeat skin test before future exposure to beta-lactam antibiotics.