The enzyme that catalyzes the formation of GDP-Lfucose from GTP and ␤-L-fucose-1-phosphate (i.e. GDP-␤-L-fucose pyrophosphorylase, GFPP) was purified about 560-fold from the cytosolic fraction of pig kidney. At this stage, there were still a number of protein bands on SDS gels, but only the 61-kDa band became specifically labeled with the photoaffinity substrate, azido-GDP-L-[ 32 P]fucose. Several peptides from this 61-kDa band were sequenced and these sequences were used for cloning the gene. The cDNA clone yielded high levels of GFPP activity when expressed in myeloma cells and in a baculovirus system, demonstrating that the 61-kDa band is the authentic GFPP. The porcine tissue with highest specific activity for GFPP was kidney, with lung, liver, and pancreas being somewhat lower. GFPP was also found in Chinese hamster ovary, but not Madin-Darby canine kidney cells. Northern analysis showed the mRNA in human spleen, prostate, testis, ovary, small intestine, and colon. GFPP was stable at 4 o C in buffer containing 50 mM sucrose, with little loss of activity over a 9-day period. GTP was the best nucleoside triphosphate substrate but significant activity was also observed with ITP and to a lesser extent with ATP. The enzyme was reasonably specific for ␤-L-fucose-1-P, but could also utilize ␣-D-arabinose-1-P to produce GDP-␣-D-arabinose. The product of the reaction with GTP and ␣-L-fucose-1-P was characterized as GDP-␤-Lfucose by a variety of chemical and chromatographic methods.

Autoantibodies to the adrenal cortex (AA) were sought by indirect immunofluorescence using unfixed human adrenal tissue in 1675 patients with insulin-dependent diabetes (IDD), 2032 relatives of patients with IDD, and 2543 normal subjects. The frequencies of AA were significantly greater in patients with IDD (1.8%) and their relatives (1.4%) than in normal subjects (0.6%; P less than 0.013). Women more frequently had AA than men (P less than 0.011). There were no differences in the frequencies of AA between caucasoid and black individuals in all three patient groups. Patients with AA had higher frequencies of thyroid microsomal and gastric parietal cell autoantibodies than age-, sex-, and race-matched normal subjects (P less than 0.01). Adrenal function was studied in 30 asymptomatic patients (13 with AA, including 5 with IDD, and 17 subjects with no AA, including 8 with IDD). The mean plasma levels of ACTH at 0600 and 2000 h were significantly higher in those with AA than in matched subjects with no AA (P less than 0.01). The mean PRA levels (both recumbent and upright) were also significantly higher in those with AA than in subjects without AA (P less than 0.01). However, serum cortisol and aldosterone concentrations or 24-h urinary cortisol and aldosterone excretion were no different between the groups. These patients, therefore, appear to have compensated adrenal hypofunction, with the compensation maintained by increased ACTH and renin secretion. Whether these patients will remain in this compensated state of adrenal dysfunction or whether they will develop overt adrenal insufficiency requires longer follow-up.

Microalbuminuria is independently associated with diabetic neuropathy. This association lends support to the theory of a vascular etiology for diabetic distal symmetrical neuropathy.

We report nine patients with a sixth band, migrating cathodic to lactate dehydrogenase 5, appearing on routine electrophoresis for serum lactate dehydrogenase (LD, EC 1.1.1.27). Eight of these patients died during their hospitalization. Acidosis, hypotension, and sepsis were the common clinical conditions preceding the band's appearance. In several cases the band appeared transiently. We examined tissue samples from two of the cases, finding LD-6 in liver and skeletal muscle but not in heart. In randomly selected autopsy tissues, LD-6 was detected consistently in liver and skeletal muscle, sometimes in spleen, kidney, and adrenal tissue, but never in heart. Biochemical studies indicate that the LD-6 isoenzyme is not an artifact or an immunoglobulin complex, is larger than the other LD isoenzymes, contains an M-subunit but not an H-subunit, has an isoelectric point in the pH range of 9.0-9.6, and is more heat stable than LD-5.

No abstract