Poststreptococcal glomerulonephritis in the elderly. Report of a case and review of the literature.

Acute poststreptococcal glomerulonephritis (PSGN) is uncommonly seen in the elderly population and its diagnosis is not without some difficulty because clinical manifestations may mimic other diseases. Renal biopsy for diagnosis and early intervention, if indicated, is very valuable in such a situation. We present here a case of an elderly patient with PSGN and a review of the literature. In addition to the typical clinical manifestations of the disease, dyspnea and pulmonary congestion are commonly present in elderly patients, probably a result of excessive salt and water retention in the face of compromised cardiovascular function. Elderly patients with PSGN appear to have a remarkably poor prognosis, with significant incidences of acute mortality and chronic renal disease. Our patient had the unusual finding of a large number of glomerular crescents with near complete clinical recovery after short-term follow-up.

Structure and heme environment of beef liver catalase at 2.5 A resolution.

Most of the amino acid side chains of beef liver catalase were clearly identifiable in the 2.5 A resolution electron-density map, and the results are in good agreement with the sequence [Schroeder, W. A., Shelton, J. R., Shelton, J. B., Roberson, B. & Apell, G. (1969) Arch. Biochem. Biophys. 131, 653-655]. The tertiary structure of one subunit consists of a large antiparallel beta-pleated sheet domain with helical insertions, followed by a smaller domain containing four alpha-helices. The heme group is buried at least 20 A below the molecular surface and is accessible by a channel lined with hydrophobic residues. The proximal ligand is tyrosine-357, while histidine-74 and asparagine-147 re the important residues on the distal side of the heme. The inhibitor 3-amino-1,2,4-triazole, which has been shown to covalently bond to histidine-74, can be built into the heme cavity with its N(2) atom coordinated to the heme iron.

Structural features of the phosphoribosyltransferases and their relationship to the human deficiency disorders of purine and pyrimidine metabolism.

Similarities in the physical and chemical properties of the phosphoribosyltransferase family of enzymes suggest that they may share common structural features as observed in other functionally related proteins. The unusually high incidence of structural gene mutations of these enzymes in man are associated with several metabolic diseases of purine and pyrimidine metabolism. It is proposed that these disorders are the consequence of structural mutations to an architectural domain common to all of the phosphoribosyltransferases.

The structure of mouse testicular lactate dehydrogenase isoenzyme C4 at 2.9 A resolution.

The structure of lactate dehydrogenase isoenzyme C4 from mouse testes was solved at 2.9 A resolution using the technique of molecular replacement. The electron density map revealed a ternary-like configuration of the flexible loop peptide although density corresponding to the coenzyme and substrate molecules was not present. Apparently the apo-lactate dehydrogenase molecule in solution is in a dynamic equilibrium between the O (loop open as found in dogfish apo-lactate dehydrogenase M4) and C (loop closed as found in a variety of ternary complexes) conformations. During crystallization of the apoenzyme one or the other conformers is selected. The apparent stability of the closed conformation for the apo-lactate dehydrogenase C4 molecule may in part explain the low catalytic turnover number of the C isoenzyme. A possible substitution of an arginine residue at position 30 may also be a contributing factor as well as allowing NADP to act as coenzyme.

The tentative amino acid sequencing of lactate dehydrogenase C4 by X-ray diffraction analysis.

A tentative amino acid sequence of mouse testicular lactate dehydrogenase C4 was deduced from an electron density map and comparison with five other known lactate dehydrogenase sequences. The amino acid composition determined by chemical analysis agrees reasonably well with the present results. Necessary changes in amino acids were largely conservative and confined to the external portions of the molecule. Residues in the Q and P subunit contact regions were particularly well conserved as were most internal residues. The minimum base change/codon was similar between the C and H isoenzymes and between the C and M isoenzymes.