The highly symmetric pyruvate dehydrogenase multienzyme complexes have molecular masses ranging from 5 to 10 million daltons. They consist of numerous copies of three different enzymes: pyruvate dehydrogenase, dihydrolipoyl transacetylase, and lipoamide dehydrogenase. The three-dimensional crystal structure of the catalytic domain of Azotobacter vinelandii dihydrolipoyl transacetylase has been determined at 2.6 angstrom (A) resolution. Eight trimers assemble as a hollow truncated cube with an edge of 125 A, forming the core of the multienzyme complex. Coenzyme A must enter the 29 A long active site channel from the inside of the cube, and lipoamide must enter from the outside. The trimer of the catalytic domain of dihydrolipoyl transacetylase has a topology identical to chloramphenicol acetyl transferase. The atomic structure of the 24-subunit cube core provides a framework for understanding all pyruvate dehydrogenase and related multienzyme complexes.

This series increases the limited knowledge of mutations and phenotypes of this rare disorder. Mutation analysis of the CaSR gene facilitates patient and family management. Low dosages of calcitriol resulted in less frequent renal calcifications.

Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21-hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.

Durch thermischen Abbau von C8K sowie durch Umsetzung von Graphit mit Kalium und Rubidium konnten weitere Alkaligraphitverbindungen mit Alkalischichten in nur jeder 3., 4. oder 5. basisparallelen Schichtlücke des Graphitgitters erhalten werden. Die Zusammensetzung der 2. Stufe — bisher als C16Me formuliert — entspricht C24Me, die der folgenden Stufen im Idealfall C36Me, C48Me, C60Me. Bei allen Stufen haben die den Alkalischichten benachbarten Kohlenstoffschichten identische Lagen übereinander, während die anderen C‐Ebenen wie im Graphit zueinander orientiert sind. Für die 1. Stufe, C8Me, wird ein neuer Strukturvorschlag entwickelt. Magnetische Messungen geben für die 1.–5. Stufe einen schwachen Paramagnetismus.

The prevalence of nonsecretory MTC was low (0.83% of patients with MTC). Diagnosis was often made at a clinically advanced tumor stage. The histological and immunohistological characteristics and the clinical course and prognosis of nonsecretory MTC are markedly heterogeneous. A high Ki-67 PI and a large proportion of cells with RET 918 mutations are associated with a poor prognosis.

Calcilytics might offer medical treatment for patients with autosomal dominant hypocalcemia caused by calcilytic-sensitive CaSR mutants.

No abstract

Therefore, calcimimetics might offer medical treatment for symptomatic FHH patients, and more important, for patients with neonatal severe hyperparathyroidism that harbor calcimimetic-sensitive CaSR mutants.