Osteitis fibrosa cystica generalizata with adult T-cell leukaemia: a case report.

We report on a 62-year-old female initially suffering from extreme pain in both her lower extremities. Plain radiographs revealed multiple osteolytic lesions. Laboratory analyses indicated high levels of serum calcium and parathyroid hormone related protein (PTHrP) and detected HTLV-1 antibody. Histological examination of biopsied specimens which were obtained from osteolytic lesions indicated osteitis fibrosa cystica (OFC) without tumour cells. After the initial biopsy, a subcutaneous mass developed in the left thigh. Microsections of the biopsied mass disclosed adult T-cell leukaemia (ATL) neoplastic cells. Immunohistochemical findings revealed that PTHrP secreted from ATL neoplastic cells induced the OFC.

Characteristics of blood vessels feeding the femoral head liable to osteonecrosis in spontaneously hypertensive rats.

In order to elucidate the cause of osteonecrosis of the femoral head in spontaneously hypertensive rats (SHRs), which resembles the osteonecrosis of Perthes' disease, we observed the three-dimensional structure of vascular casts of the blood vessels feeding the femoral head using both optical and scanning electron microscopes. During the period of 9-15 weeks after birth, when osteonecrosis of the femoral heads in SHRs occurred frequently, the lateral epiphyseal vessels (LEVs), which were the main feeding vessels, entered from the lateral of the femoral heads. Anastomosing branches of LEVs between the epiphysis and the femoral neck were scarce even in the femoral heads showing normal ossification. It seemed that the development of LEVs in SHRs did not proceed normally in this period. Furthermore, remarkable segmental stenosis and the obstruction of LEVs were often recognized near the lateral of the femoral heads. These results suggest that LEVs in growing SHRs have the vascular structure that could cause an interruption of the blood supply to the femoral heads.

Vascular occlusion and cartilage disorders in osteonecrosis of the femoral head in rats.

The aim of our study was to clarify the role of lateral epiphyseal vessels in the development of femoral head osteonecrosis in rats. We did this by performing histological and immunological studies on rats at the age that they are most prone to spontaneous osteonecrosis. We observed that obstruction of the lateral epiphyseal vessels occurred at the site of cartilage penetration. This obstruction preceded the development of osteonecrosis in adjacent areas of the femoral head. We propose that a similar mechanism may be responsible, in part, for the development of Perthes disease in man.

Purification and some properties of a specific nuclease which cleaves transfer RNA precursors from the posterior silk gland of Bombyx mori.

A specific endonuclease involved in the processing of tRNA precursors was isolated and partially purified from the posterior silk gland of Bombyx mori, and designated as RNase P.Bmo. This enzyme was shown to catalyze the conversion of 4.5 S precursor RNA to 4.1 S RNA by trimming the 5'-additional segment from the precursor RNA. RNase P.Bmo required divalent cations, Mg2+ or Mn2+. In the presence of these divalent cations, K+ or NH4+ activated the RNase P.Bmo reaction. Optimum pH was observed around 8.0. Ribosomal RNA's and mature tRNA from the silk gland were not cleaved by RNase P.Bmo. A 4.5 S precursor RNA fraction containing formycin, an adenosine analog, was less susceptible to RNase P.Bmo than the normal one. These results indicate that RNase P.Bmo has a high substrate specificity. An additional nuclease(s) was isolated. This activity was assumed to remove the extra 3'-segment of the 4.5 S precursor RNA.

The effect of formycin on the processing of transfer RNA precursors in the posterior silk gland of Bombyx mori.

Formycin, an adenosine analog, was used in studies of RNA synthesis by silk glands of silkworms in organ culture. Formycin has been shown to inhibit preferentially the incorporation of [3H]uridine into low molecular weight RNA in the cytoplasm. When silk glands were pulse-chase labeled with [3H]uridine in the presence of formycin, the synthesis of 4.5S tRNA precursors was not affected, as determined by gel electrophoresis. However, the accumulation of mature 4S tRNA was greatly reduced in the formycin-treated system, although the precursors synthesized disappeared from the 4.5S region on chase at the same rate as in the control system. [14C]Formycin was incorporated into the 4.5S precursors but not into 4S tRNA. These findings suggest that the inhibition of tRNA synthesis by formycin is due to the existence of some degradation mechanisms of formycin-containing 4.5S precursor RNA's and the failure to process them into normal 4S tRNA.

The biosynthesis of transfer RNA in insects. II. Isolation of transfer RNA precursors from the posterior silk gland of Bombyx mori.

The occurrence of precursors to tRNA in the post-polysomal fraction of the posterior silk gland of Bombyx mori was demonstrated by pulse-chase labeling and DNA-RNA hybridization competition experiments. These precursors had molecular sizes ranging from 4S to 5S on polyacrylamide gel electrophoresis. Analysis of the incorporation of the methyl group from [methyl-14C]methionine revealed that a radioactive peak on polyacrylamide gel appeared in the 4.5S region during brief labeling. This suggested that some methylation occurred at the 4.5S precursor step.

The biosynthesis of transfer RNA in insects. I. Increase of amino acid acceptor activity of specific tRNA's utilized for silk protein biosynthesis in the silk gland of Bombyx mori.

1) To detect the quantitative changes of amino acid acceptor activity of tRNA's from the posterior and middle silk glands of Bombyx mori at various ages, a relatively simple and rapid method was established using a mixture of radioactive amino acids in Chlorella hydrolysate. 2) The acceptor activities of silk gland tRNA for 15 amino acids tested seemed to be almost on the same level at the end of the 4th moult stage. During the 5th instar, however, characteristic increases were observed in glycine, alanine, and serine acceptor activities in both silk glands. 3) In the posterior silk gland, which produces fibroin, the acceptor activities for glycine and alanine increased more than that for serine. In the middle silk gland, which produces sericine, the acceptor activity for serine increased more than those for glycine and alanine. 4) In the light of observations on the increase of corresponding aminoacyl-tRNA synthetase activities in the silk glands, a functional adaptation of tRNA synthesis in the tissue is discussed.