A large family with features of pseudoachondroplasia and multiple epiphyseal dysplasia: exclusion of seven candidate gene loci that encode proteins of the cartilage extracellular matrix

We have identified a large family with a dominantly inherited chondrodysplasia characterized by a waddling gait, short limbs, and early onset osteoarthritis. The radiographic presentation resembles pseudoachondroplasia in childhood and multiple epiphyseal dysplasia in adults. Electron microscopic examination of cartilage reveals accumulation of material within the rough endoplasmic reticulum similar to that seen in pseudoachondroplasia and the Fairbank type of multiple epiphyseal dysplasia. By linkage analysis, we have excluded the genes for aggrecan, decorin, hexabrachion (tenascin), type II procollagen, the 1 chain of type XI procollagen, the 1 chain of type IX procollagen, and link protein, candidate genes that encode structural components of the cartilage extracellular matrix, as the disease locus for this disorder.     

Analysis of spontaneous base substitutions generated in mismatch-repair-deficient strains of Escherichia coli.

We used the lacI system of Escherichia coli to examine the distribution of base substitution mutations occurring spontaneously in different mismatch-repair-deficient strains. The examination of almost 1,200 nonsense mutations generated in strains carrying the mutS, mutH, and mutU alleles confirmed that transitions are highly favored over transversions. The detailed analysis of relative mutation rates at different sites revealed that the pattern of hot spots and cold spots is strikingly similar in each of the three strain backgrounds, strongly supporting the notions that the products of the three genes are part of the same system and that in the absence of any of the components the entire system fails to function. The distribution of mutations occurring in the absence of mismatch repair defined a pronounced topography of the lacI gene. There was no obvious correlation of the hot spots or cold spots with either nearest-neighbor sequences or A X T richness of the immediate surrounding sequence.     

Cardiopulmonary adaptations to pneumonectomy in dogs. I. Maximal exercise performance.

Maximal exercise performance was evaluated in four adult foxhounds after right pneumonectomy (removal of 58% of lung) and compared with that in seven sham-operated control dogs 6 mo after surgery. Maximal O2 uptake (ml O2.min-1.kg-1) was 142.9 +/- 1.9 in the sham group and 123.0 +/- 3.8 in the pneumonectomy group, a reduction of 14% (P less than 0.001). Maximal stroke volume (ml/kg) was 2.59 +/- 0.10 in the sham group and 1.99 +/- 0.05 in the pneumonectomy group, a reduction of 23% (P less than 0.005). Lung diffusing capacity (DL(CO)) (ml.min-1.Torr-1.kg-1) reached 2.27 +/- 0.08 in the combined lungs of the sham group and 1.67 +/- 0.07 in the remaining lung of the pneumonectomy group (P less than 0.001). In the pneumonectomy group, DL(CO) of the left lung was 76% greater than that in the left lung of controls. Blood lactate concentration and hematocrit were significantly higher at exercise in the pneumonectomy group. We conclude that, in dogs after resection of 58% of lung, O2 uptake, cardiac output, stroke volume, and DL(CO) at maximal exercise were restricted. However, the magnitude of overall impairment was surprisingly small, indicating a remarkable ability to compensate for the loss of one lung. This compensation was achieved through the recruitment of reserves in DL(CO) in the remaining lung, the development of exercise-induced polycythemia, and the maintenance of a relatively large stroke volume in the face of an increased pulmonary vascular resistance.     

Application of high-performance liquid chromatography for the study of the microheterogeneity changes of mouse alpha-fetoprotein in fetal development

Changes in the microheterogeneity of mouse alpha-fetoprotein (MAFP) during fetal development were investigated by high-performance liquid chromatography (HPLC). A total of six distinct isoforms (Iso-1, Iso-2, Iso-3, Iso-4, Iso-5, Iso-6) of the heterogeneous MAFP were resolved from mouse amniotic fluid (MAF). Analysis of MAF collected at various times revealed that these isoforms were accumulated at different stages of the fetal development.     

Effects of Ca2+ and membrane surface charge on the direct lytic activity of cobra cardiotoxin - a membrane spin assay.

Direct membrane lytic activity of cobra (Naja Naja atra) cardiotoxin was studied by measuring the release of trapped spin label (2,2,6,6-tetramethyl-piperidinyloxyl)-choline chloride from liposomes. Results suggest that (a) presence of membrane negative charge and Ca²⁺ are required for optimal direct lytic activity of cardiotoxin, (b) direct Ca²⁺ binding to cardiotoxin may affect the equilibrium between its membrane active and inactive form.