Bioavailability of zinc to rats as affected by protein source and previous dietary intake

The bioavailability of zinc from defatted soy flour, dried chicken meat or mixed (50:50 dry weight basis) soy flour and chicken meat included in egg white-based diets was investigated in rats. Following a 6-d experimental diet (9 ppm Zn) feeding period, marginally zinc-depleted weanling rats were fed a test meal, identical in composition to the experimental diet except that the protein source was labeled either intrinsically or extrinsically with 65Zn. Retention of 65Zn from the chicken test meal was significantly higher than that from the soy test meal. Retention of 65Zn from the mixed soy/chicken test meal was midway between the retention values for either protein alone regardless of which protein source was labeled. Intrinsic and extrinsic labeling techniques resulted in similar assessment of zinc bioavailability. Additionally, the influence of previous dietary protein source on zinc retention from a soy test meal was investigated. Retention of 65Zn from an intrinsically labeled soy test meal was higher in rats adapted to chicken protein than in rats adapted to soy protein. The levels of tibia zinc and tibia 65Zn were associated with whole-body retention of 65Zn.     

Dysfunction of axonemal dynein heavy chain Mdnah5 inhibits ependymal flow and reveals a novel mechanism for hydrocephalus formation

Motility of unicellular organisms occurred early in evolution with the emergence of cilia and flagella. In vertebrates, motile cilia are required for numerous functions such as clearance of the airways and determination of left-right body asymmetry. Ependymal cells lining the brain ventricles also carry motile cilia, but their biological function has remained obscure. Here, we show that ependymal cilia generate a laminar flow of cerebrospinal fluid through the cerebral aqueduct, which we term as 'ependymal flow'. The axonemal dynein heavy chain gene Mdnah5 is specifically expressed in ependymal cells, and is essential for ultrastructural and functional integrity of ependymal cilia. In Mdnah5-mutant mice, lack of ependymal flow causes closure of the aqueduct and subsequent formation of triventricular hydrocephalus during early postnatal brain development. The higher incidence of aqueduct stenosis and hydrocephalus formation in patients with ciliary defects proves the relevance of this novel mechanism in humans.     

Diagnostische Genauigkeit der Dual-energy-CT-Angiographie bei Patienten mit Diabetes mellitus

Die Radiologie - Die periphere arterielle Verschlusskrankheit (PAVK) ist eine wesentliche Komplikation des Diabetes mellitus und stellt aufgrund ausgeprägter Gefäßverkalkungen eine...     

Duchenne's muscular dystrophy: also in girls?

Duchenne's muscular dystrophy is inherited as a recessive X-linked trait: Even-though it rarely appears in females it can be seen. We have examined 5 children of one family. Two boys and one girl showed typical symptoms and clinical as well as light- and electronmicroscopical findings of this disease. In order to understand the mode of the genetic pattern, we have analysed the chromosomes, proved the fatherhood and assured the increased Ca-pooling in non-necrotic muscle fibers; in vitro-examinations of the amino-acid-incorporation in ribosomes and of the synthesis of collagen in muscular cells were done as well. Evaluating all of the results, the inheritance must be X-linked recessive and the girl, with high incidence, is a so called "manifesting carrier". The explanation offers Lyons hypothesis, which suggests that in most of the girl's muscle cells the X-Chromosomes, inherited from the mother, are active and lead to the manifestation of the illness. Consequences in advising the family genetically must be taken.     

Ergebnisse klinischer,biochemischer, lichtmikroskopischer und ultrastruktureller Untersuchungen einer kindlichen Muskelglykogenose bei zwei Brüdern und deren schwester

Zusammenfassung Es wird über eine abortive muskuläre Form der Typ II-Glykogenose (Pompe) bei drei Geschwistern (zwei Buben und deren Schwester) berichtet.Die klinischen und routinehistologischen Befunde entsprechen dem Bild einer primär degenerativen Myopathie. Erst spezielle lichtmikroskopische (PAS-Reaktion), elektronenmikroskopische und biochemische Untersuchungen führten zur Sicherung der Diagnose.Im elektronenmikroskopischen Bild weisen die betroffenen Muskelzellen aller drei Geschwister große, autophage Vacuolen auf, die neben aggregierten Glykogengranula häufig myelinartige Abbauprodukte cytoplasmatischer Membranen enthalten. Daneben werden unspezifische Veränderungen an den übrigen Zellorganellen und den Myofibrillen beobachtet. Die biochemische Untersuchung einer Muskelbiopsie ergibt den Nachweis eines Mangels an -1,4-Glucosidase.

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Results of clinical, biochemical, Light-microscopical and ultrastructural studies of childhood glycogenosis in two brothers and their sister

Summary This report describes a mild muscular form of type II glycogenosis (Pompe) in 3 children (two boys and their sister).The clinical picture and results of routine histological tests were in keeping with the picture of a primary degenerative myopathy. It was not possible to confirm the diagnosis until special preparations were examined by light microscopy (PAS stain) and by electromicroscopical and biochemical techniques.Electron-microscopical examination of muscle cells from the affected areashowed large, autophagic vacuoles in all three sibs, which contained aggregated glycogen granules and myelin-like degradation products of cytoplasmic membranes. Nonspecific changes of the other cell organelles and the myofibrils were also observed. Biochemical examination of a muscle biopsy revealed an -1,4-glucosidase deficiency.

Wir danken Frau Prof. Dr. E. Freund-Mölbert (Lehrstuhl für Mikrobiologie, Biologie II der Universität Freiburg i. Br.) für ihre freundliche Unterstützung.     

Primary systemic carnitine deficiency under successful therapy: clinical, biochemical, ultrahistochemical and renal clearance studies

Systemic carnitine deficiency is an often fatal, but treatable metabolic disorder which should be considered in any child with repeated episodes of a Reye-like syndrome or a cardiomyopathy. A 4-year-old girl with a typical history and clinical findings was successfully treated with oral carnitine. Despite low liver carnitine, ketogenesis upon fasting was normal. Normal muscle function under therapy was associated with unchanged low muscle carnitine levels. Improvement of mitochondrial structure and function was demonstrated by controlled ultrahistochemical studies. A renal carnitine leak, evident from renal clearance studies, may contribute to the pathogenesis of systemic carnitine deficiency.     

Freeze-fracturing studies of mitochondrial myopathy. A correlated clinical, biochemical and morphological investigation

Freeze-fracture studies of pathologically changed mitochondria in situ from muscle biopsies of a 9.5-year-old girl with a mitochondrial myopathy were correlated with clinical, biochemical and histochemical investigations. In the ultrathin sections giant mitochondria with densely packed cristae membranes - often reoriented to concentric circles - and, in addition, paracrystalline mitochondrial inclusions were found. The freeze fracture faces of such transformed mitochondria and preparations of their inner and outer membranes provided a morphological insight in the macromolecular structure of the mitochondrial membrane under such pathological conditions. The results lead to the hypothesis that part of the transformed mitochondria stay active functionally for an extended period by maintaining the delimitation from the cytoplasm and by preserving the macromolecular membrane architecture. This hypothesis could explain the slow progression of the myogenic symptoms.