Kinetics and thermodynamics of beta 2-microglobulin binding to the alpha 3 domain of major histocompatibility complex class I heavy chain.

The major histocompatibility complex (MHC) class I molecule plays a crucial role in cytotoxic lymphocyte function. Functional class I MHC exists as a heterotrimer consisting of the MHC class I heavy chain, an antigenic peptide fragment, and beta2-microglobulin (beta2m). beta2m has been previously shown to play an important role in the folding of the MHC heavy chain without continued beta2m association with the MHC complex. Therefore, beta2m is both a structural component of the MHC complex and a chaperone-like molecule for MHC folding. In this study we provide data supporting a model in which the chaperone-like role of beta2m is dependent on initial binding to only one of the two beta2m interfaces with class 1 heavy chain. beta2-Microglobulin binding to an isolated alpha3 domain of the class I MHC heavy chain accurately models the biochemistry and thermodynamics of beta2m-driven refolding. Our results explain a 1000-fold discrepancy between beta2m binding and refolding of MHC1. The biochemical study of the individual domains of complex molecules is an important strategy for understanding their dynamic structure and multiple functions.

Challenges in delivering peritoneal dialysis to a premature infant.

The proposed outcomes for C.Q. were achieved. Communication between dietician, neonatal intensive care and pediatric nursing staff, pediatric nephrology nurses and physicians played a critical role in providing optimal care for C.Q. Due to her multiple problems, it was imperative that all disciplines collaborate and coordinate their care. The meticulous supervision by the staff nurses allowed this tiny patient to overcome her multiple problems. Careful follow-up included monitoring nutritional markers, laboratory results, and adequacy of dialysis. It is also important to note that open communication by the nephrology nurses allows small patients like C.Q. to have enhanced quality of life at home with their families. C.Q. is now a thriving infant, cared for by her mother at home.

Preparing a child with obstructive sleep apnea for transplantation.

All of the expected outcomes have been met for A.W. Intense collaboration among the pulmonary, nutrition, transplant, nephrology teams, and A.W.'s parents have accomplished what at first seemed to be quite difficult. After months of hard work and close monitoring of A.W., he was now at the 90th percentile on the growth curve. The diligence of the dietician and A.W.'s parents provided the intended outcome. A.W. had achieved a manageable weight and could be safely transplanted. The transplant team has decided to quickly taper prednisone until A.W. is completely off of this immunosuppressive after transplantation. A.W. is more cooperative with the nasal cannula at night and it is felt he will cooperate with the CPAP mask during the post-operative period in the hospital. He would need continued evaluation of his obstructive sleep apnea due to the potential of increased weight with immunosuppression medicines. All of A.W.'s blood culture results have been negative and his left tympanic membrane has not drained nor is there evidence of infection. A.W. is finally ready for transplantation. A date was set and A.W. and his living related donor were ready to proceed.

A general method of isolating high molecular weight DNA from methanogenic archaea (archaebacteria).

High molecular weight DNA was readily isolated from all methanogens treated, as well as from thermophilic anaerobic eubacteria, by grinding cells frozen in liquid N2, prior to lysis with SDS. DNA can subsequently be purified by the usual phenol-chloroform extractions. The procedure yields DNA readily cut by restriction enzymes and suitable for oligonucleotide probing, as well as for mole percent G + C content determination by thermal denaturation. The method routinely yields DNA of high molecular weight and is an improvement over DNA isolation methods for many methanogens, which often involve an initial breakage of the cells in a French pressure cell.

Heat shock response of the archaebacterium Methanococcus voltae.

The general properties of the heat shock response of the archaebacterium Methanococcus voltae were characterized. The induction of 11 heat shock proteins, with apparent molecular weights ranging from 18,000 to 90,000, occurred optimally at 40 to 50 degrees C. Some of the heat shock proteins were preferentially enriched in either the soluble (cytoplasm) or particulate (membrane) fraction. Alternative stresses (ethanol, hydrogen peroxide, NaCl) stimulated the synthesis of subsets of the heat shock proteins as well as unique proteins. Western blot (immunoblot) analysis, in which antisera to Escherichia coli heat shock proteins (DnaK and GroEL) were used, did not detect any immunologically cross-reactive proteins. In addition, Southern blot analysis did not reveal any homology between M. voltae and four highly conserved heat shock genes, mopB and dnaK from E. coli and hsp70 genes from Drosophila species and Saccharomyces cerevisiae.