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We have studied nuclear forward scattering of synchrotron radiation for the 67.41 keV resonance of 61Ni using a silicon crystal monochromator with low-index reflections and a multielement detector. This approach can be extended to other high-energy Mössbauer transitions and does not pose any restrictions on the sample environment. Under conditions of large sample thickness and short nuclear lifetime, typical for work with high-energy nuclear resonances, the nuclear decay follows a universal dependence where both thickness effects and hyperfine interactions are taken into account by time scaling.

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Using probe molecules with resonant nuclei and nuclear inelastic scattering, we are able to measure the density of states exclusively for collective motions with a correlation length of more than approximately 20 A. Such spectra exhibit an excess of low-energy modes (boson peak). This peak behaves in the same way as that observed by conventional methods. This shows that a significant part of the modes constituting the boson peak is of collective character. At energies above the boson peak, the reduced density of states of the collective motions universally exhibits an exponential decrease.

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We have applied nuclear inelastic absorption (NIA) to the molecular glass former dibutyl phthalate/ferrocene, both in bulk and in nanoporous matrices having pore sizes of 50 and 25 A. The quantity g(E)/E(2), where g(E) is the vibrational density of states (VDOS) of the iron atoms, exhibits a pronounced maximum around 2 meV. Confinement in pores leads to a suppression of the VDOS below 1.5 meV, independent of the pore size. The influence of local interactions at the pore wall was assessed using Raman scattering. Our observations are discussed in the light of experimental and theoretical results on nanoparticles and for the Boson peak.

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The phonon-assisted Mössbauer effect is used to determine the partial phonon density of states of the iron within the active center of deoxymyoglobin, carboxymyoglobin, and dry and wet metmyoglobin between 40 and 300 K. Between 0 and 1 meV the iron density of states increases quadratically with the energy, as in a Debye solid. Mean sound velocities are extracted from this slope. Between 1 and 3 meV a nearly quadratic "Debye-like" increase follows due to the similar strength of intermolecular and intramolecular forces. Above 3 meV, optical vibrations are characteristic for the iron-ligand conformation. The overall mean square displacements of the heme iron atom obtained from the density of states agree well with the values of Mössbauer absorption experiments below 180 K. In the physiological temperature regime the data confirm the existence of harmonic vibrations in addition to the protein specific dynamics measured by Mössbauer absorption. In the Debye energy regime the mean square displacement of the iron is in agreement with that of the hydrogens measured by incoherent neutron scattering demonstrating the global character of these modes. At higher energies the vibration of the heavy iron atom at 33 meV in metmyoglobin is as large as that of the lightweight hydrogens at that energy. A freeze dried, rehydrated (h=0.38 g H2O/g protein) metmyoglobin sample shows an excess of states above the Debye law between 1 and 3 meV, similar to neutron scattering experiments. The room temperature density of states below 3 meV exhibit an increase of the density compared to the low temperature data, which can be interpreted as mode softening.

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Nuclear forward scattering of synchrotron radiation is used to determine the quadrupole splitting and the mean square displacement of the iron atom in deoxymyoglobin in the temperature range between 50 K and 243 K. Above 200 K an abnormally fast decay of the forward scattered intensity at short times after the synchrotron flash is observed, which is caused by protein-specific motions. The results strongly support the picture that protein dynamics seen at the position of the iron can be understood by harmonic motions in the low temperature regime while in the physiological regime diffusive motions in limited space are present. The shape of the resonance broadening function is investigated. An inhomogeneous broadening with a Lorentzian distribution indicating dipole interactions results in a better agreement with the experimental data than the common Gaussian distribution.

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Three new observations of trisomy 8 mosaicism are presented. In two postnatal cases, both patients showed agenesis of corpus callosum associated with different clinical findings. In a third case, the prenatal diagnosis revealed trisomy 8 mosaicism exclusively in chorionic villi (CV) cells long term culture. Normal results were obtained in CV direct preparation and in cultured amniotic cells. In lymphocytes, the child showed low level trisomy 8 mosaicism. The only clinical findings were deep palmar and plantar furrows. The present cases as well as reports in the literature indicate that the variation in tissular repartition of normal and trisomic clones in trisomy 8 mosaicism is possibly responsible for the missing correlation between cytogenetic findings and clinical severity in this syndrome.

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A 20-month-old girl showed typical clinical signs of Farber disease: hoarseness since birth, and periarticular subcutaneous painful nodules. Complete deficiency of acid ceramidase activity was found in cultured skin fibroblasts. An electron microscopic examination of a dermal nodule disclosed pathognomonic tubular inclusions in histiocytes. In epidermal cells zebra-body-like and needle-like lysosomal inclusions were found. Their ultrastructure is different from that of the intrahistiocytic lysosomal inclusions. Probably three clinical types of Farber disease may be distinguished according to the symptomatology and the course of the disease: a severe type, an intermediate type and a relatively mild type. The activity of acid ceramidase does not correlate with prognosis of the disease, while a correlation between first appearance of dermal nodules and clinical course appears likely.

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Two fetuses at risk for X-linked recessive Duchenne muscular dystrophy and five affected boys were examined by electronmicroscopy. In all cases, numerous activated lymphocytes were found in different stages of invasion in muscle cells. Characteristic aggressor-muscle cell interactions were manifest by successive phases of cell-to-cell adherence and muscle cell destruction. Cell-mediated cytolysis may play an important role in the pathogenesis of Duchenne muscular dystrophy.

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A girl with unilateral partly depigmented, partly hyperpigmented atrophic skin lesions, hypertrichosis, postauricular nodules, cataracts, and mild mental retardation is presented. Additionally, she developed multiple neoplasms as optic glaucoma, a psammomatous meningioma and an ameloblastoma. It remains unclear whether our patient suffers from a variant of the epidermal nevus syndrome or a new neuro-ectodermal dysplasia.

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In 102 out of 127 patients who had congenital malformations of the eye and the orbit these malformations were part of a syndrome. Only 11 patients had a single ocular anomaly without associated malformations. Of the remaining 116 patients, 69.3% had associated anomalies of the nervous system, 48% had associated malformations of the connective tissue, 25.6% had anomalies of the skin and its appendages, 23.6% had malformations of the visceral organs, especially the urinary and intestinal tracts, and 22% had cardiovascular malformations. Anomalies of the ears and the auricles were present in 21%. Of these patients who had ocular abnormalities associated with other malformations, 45% had a chromosomal aberration; 44 of the 56 children afflicted with chromosomal anomalies had Down's syndrome. The high incidence of ocular anomalies associated with other malformations attests to the necessity of comprehensive investigations, including cytogenetic studies, to confirm or rule out chromosomal aberrations. In addition, detailed family studies to check for the existence of formes frustes are essential. Genetic counseling is indicated in every family which has a member with a congenital ocular anomaly.

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The majority of patients with hemifacial microsomia (HM) including Goldenhar syndrome are sporadic cases. The sporadic nature of this disorder is emphasized by the discordant occurrence of HM in one of female monozygotic twins reported here. Previous publications, however, also suggest autosomal dominant and autosomal recessive modes of inheritance. Possible formes frustes will also have to be considered when giving genetic counsel.

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