Proteolytic activity in human burn wounds

Wound healing is the result of a dynamic balance between synthetic and degradative processes. After a burn, proteolytic activity increases at the wound site. Excised burn wounds and donor skin were examined from 20 pediatric burn patients, to determine which of two classes of neutral proteinases, serine or metalloproteinases, accounts for the majority of this proteolytic activity in these tissues; to examine messenger RNA expression of three of the principal enzymes and inhibitors of this class; and to measure enzymatic activity of two of these metalloproteinases. The majority of the increased proteolysis was due to metalloproteinases. By polymerase chain reaction assays, messenger RNAs for matrix metalloproteinase-1, -3, and -9 were strongly expressed in burn tissue and absent or weakly expressed in unburned skin. Messenger RNA for tissue inhibitor of metalloproteinase-1 and -2 was consistently present in burned and unburned skin. By zymography, there was a significant increase in matrix metalloproteinase-2 (twofold to threefold) and matrix metalloproteinase-9 (20- to 30-fold) activity in burned versus unburned skin. We suggest that postburn there is an upregulation of some matrix metalloproteinases that exceeds the level of inhibitors with the net result of an increase in proteolysis in burned tissue. This increased proteolysis may play a role in wound repair and scar formation.

Evaluating systems of care for children: utility of the clinical case conference

A clinical assessment of the Mental Health Services Program for Youth, a national initiative to integrate systems and coordinate care for severely emotionally disturbed children, was designed to augment and enrich the larger evaluation of program structure. Case conferences were used as a method of examining the effects of collaborative systems of care on vulnerable individuals and of generating clinical insight and understanding. Case vignettes are presented and discussed in terms of the contributions and shortcomings of current system-of-care efforts.

1997 up and comers

Leadership is both singular and diverse, subtle and bold. It moves others, transcends the obvious and stretches the boundaries of achievement. And it's always passionate about what it does. Being a leader in today's complex, evolving healthcare industry is an especially challenging task. Modern Healthcare salutes this year's "Up & Comers," 13 young executives, all 40 or under, who already have made their marks and will help shape the future of healthcare.

The mouse pale ear (ep) mutation is the homologue of human Hermansky-Pudlak syndrome

The recessive mutation at the pale ear (ep) locus on mouse chromosome 19 was found to be the homologue of human Hermansky-Pudlak syndrome (HPS). A positional cloning strategy using yeast artificial chromosomes spanning the HPS locus was used to identify the HPS gene and its murine counterpart. These genes and their predicted proteins are highly conserved at the nucleotide and amino acid levels. Sequence analysis of the mutant ep gene revealed the insertion of an intracisternal A particle element in a protein-coding 3' exon. Here we demonstrate that mice with the ep mutation exhibit abnormalities similar to human HPS patients in melanosomes and platelet-dense granules. These results establish an animal model of HPS and will facilitate biochemical and molecular analyses of the functions of this protein in the membranes of specialized intracellular organelles.

Evolution of the rice Xa21 disease resistance gene family

The rice disease resistance gene Xa21, encoding a receptor-like kinase, is a member of a multigene family. Sequence analysis of seven family members revealed two distinct classes of genes. One member from each class encodes a receptor kinase-like open reading frame. The other five members encode truncated open reading frames of the predicted receptor kinase. A highly conserved 233-bp sequence (HC) was also identified among the seven family members. Recombination at the HC region between family members apparently resulted in the precise swapping of promoter regions. Large sequence duplications were generated by a presumed unequal crossover event in intergenic regions. Insertions of transposon-like sequences truncated two of the predicted open reading frames. A model for amplification and diversification of the Xa21 gene family is presented.

Evolution of the rice Xa21 disease resistance gene family

The rice disease resistance gene Xa21, encoding a receptor-like kinase, is a member of a multigene family. Sequence analysis of seven family members revealed two distinct classes of genes. One member from each class encodes a receptor kinase-like open reading frame. The other five members encode truncated open reading frames of the predicted receptor kinase. A highly conserved 233-bp sequence (HC) was also identified among the seven family members. Recombination at the HC region between family members apparently resulted in the precise swapping of promoter regions. Large sequence duplications were generated by a presumed unequal crossover event in intergenic regions. Insertions of transposon-like sequences truncated two of the predicted open reading frames. A model for amplification and diversification of the Xa21 gene family is presented.