A CASE OF FOAMY MYOCARDIAL TRANSFORMATION OF INFANCY

A case of Infantile cardiomyopathy in a year and four months old girl, which was clinically characterized by tachycardia resistent to any drugs and marked hyperplasia of mitochondria in their cytoplasms on electron microscopic observation, was presented. In the present case light and electron microscopical proof of the diagnosis was obtained by right endomyocardial biopsy, while most of this condition has not been recognized prior to autopsy. In Japan this newly recognized infantile cardiomyopathy has not been reported, and we proposed that this condition could be designated as mitochondrial cardiomyopathy caused by unknown etiology. The literatures described previously in the world have been reviewed.     

Calorimetric study of tryptophan synthase α-subunit and two mutant proteins

Heat-denaturation of tryptophan synthase α-subunit from E. coli and two mutant proteins (Glu 49 ± Gln or Ser; called Gln 49 or Ser 49, respectively) has been studied by the scanning microcalorimetric method at various pH, in an attempt to elucidate the role of individual amino acid residues in the conformational stability of a protein. The partial specific heat capacity in the native state at 20°, C_p²⁰, has been found to be (0.43 ± 0.02) cal ± K^-1 ± g^-1, the unfolding heat capacity change, Δ_dC_p, (0.10 ± 0.01) cal ± K^-1 ± g^-1, and the unfolding enthalpy value extrapolated to 110°, Δ_dh¹¹⁰, (9.3 ± 0.5) cal ± g^-1 for the three proteins. The value of C_p²⁰ was larger than those found for fully compact protein and that of Δ_dh¹¹⁰ was smaller. Unfolding Gibbs energy, Δ_dG at 25° for Wild-type, Gln 49, and Ser 49 were 5.8, 8.4, and 7.1 kcal ± mol^-1 at pH 9.3, respectively. Unfolding enthalpy, Δ_dH, of the three proteins seemed to be the same and equal to (23.2 ± 1.2) kcal ± mol^-1 at 25°. As a consequence of the same value of Δ_dH and the different value in Δ_dG, substantial differences in unfolding entropy, Δ_dS, were found for the three proteins. The values of Δ_dG for the three proteins at 25° coincided with those from equilibrium methods of denaturation by guanidine hydrochloride.     

Alteration of cartilagenous proteoglycan in psoriasis

Articular tissue was obtained at surgery for a femoral neck fracture in a patient with psoriasis without arthritis. The proteoglycan of the cartilage of the sample was analysed biochemically. Normal cartilage is known to produce two types of proteoglycan monomers (fast- and slow-sedimenting groups), which are distinguishable by density-gradient ultracentrifugation. In the psoriatic cartilage analysed in the present study, it was shown that the former group was absent and only the latter group remained.     

Change of the Microstructure of Microcrystalline Cellulose with Grinding and Compression

The microstructure of microcrystalline cellulose was investigated by use of a radial distribution function (RDF) based on the intensity of X-ray scattering data. Changes in the microstructure of the cellulose as a result of grinding and compression were detected by use of the RDF. The RDF of intact microcrystalline cellulose had peak maxima corresponding to distances of approximately 1.5, 2.6, 5.0, 8.2, 13.3 and 170 Å. The first two corresponded to the intramolecular atomic distances; other peaks were attributable to the intermolecular (inter-fibre) atomic distance. Changes in the RDF as a result of grinding indicated that the regular intermolecular atomic arrangement was gradually lost. Compression resulted in formation of long-range (> 20 Å) ordering of the intermolecular (inter-fibre) atomic arrangement. These results show that RDF analysis is suitable for monitoring changes in the structure of microcrystalline cellulose which occur as a result of grinding and compression.     

Thermal denaturation of tryptophan synthase α-subunit

Thermal denaturation for the wild-type of tryptophan synthase α-subunit from E. coli and one of its mutant proteins was followed by CD measurements at various pHs in the alkaline region and the results from van't Hoff analyses of the thermal denaturation curves were compared with those from calorimetry. Although the far-u.v. CD spectra of the thermally denatured proteins differed from those of the completely denatured states in 3.2 M guanidine hydrochloride, the titration curves by denaturants at higher temperatures were not sigmoidal but straight lines, indicating that the cooperative structure of the proteins has been completely destroyed by heating. The ratio of calorimetric enthalpy change to van't Hoff enthalpy change obtained from calorimetric study was unity, indicating that the thermal denaturation of the proteins was a two-state system. The unfolding heat capacity change (ΔCp) of the wild-type protein from van't Hoff analysis of the thermal denaturation curves by CD measurement was estimated to be 2.45 kcal/mol ± deg, which was similar to that from calorimetry. The values of unfolding enthalpy change at denaturation temperatures were lower by about 15 kcal/mol compared to those from calorimetry.     

A sex reversal infant with XX karyotype and complete male external genitalia

The unusual case of a Japanese newborn XX male is presented. Examination of chromosomes in amniotic fluid cells had shown a normal female karyotype (46,XX), but ultrasonography revealed a penis and a scrotum. The neonate had normal male external genitalia, and serum levels of luteinizing hormone follicle stimulating hormone, and testosterone were all within the normal range. High resonance chromosome analysis revealed an excess portion on the short arm of one of the X chromosoms. We examined his genomic DNA by polymerase chain reaction (PCR) and detected two Y specific regions in his genomic DNA, the sex-determining region Y (SRY) and pseudoautosomal boundary Y. Nucleotide sequencing of the PCR products of SRY indicated no mutation. These findings suggested that the translocation or insertion of an SRY region on the X chromosome led to the development of testicles and a male phenotype.     

Muscle fiber–type changes induced by botulinum toxin injection in the rat larynx

This study examined muscle fiber–type alterations after single or multiple botulinum toxin (BT) injections to better understand possible morphologic changes induced by therapeutic BT injections in patients with spasmodic dysphonia. Muscle fiber staining was accomplished in rat intrinsic laryngeal muscles with antibodies to specific myosin heavy chains. Results indicated that the typical baseline distributions of type II muscle fibers (ie, types IIa, IIb, IIx, and IIL) were altered by BT injection, while no change was observed in type I fibers. Embryonic fibers were observed only along the needle insertion site at 7 days post BT injection. Although inferences from these animal data to human neuromuscular function must be made with caution, our findings provide insight into the possible cellular and molecular changes characterizing BT-injected muscles. (Otolaryngol Head Neck Surg 1999;120:876-83.)