Mitochondrial porin of Neurospora crassa: cDNA cloning, in vitro expression and import into mitochondria.

cDNA encoding porin of Neurospora crassa, the major protein component of the outer mitochondrial membrane, was isolated and the nucleotide sequence was determined. The deduced protein sequence consists of 283 amino acids (29,979 daltons) and shows sequence homology of around 43% to yeast porin; however, no significant homology to bacterial porins was apparent. According to secondary structure predictions, mitochondrial porin consists mainly of membrane-spanning sided beta-sheets. Porin was efficiently synthesized in vitro from the cDNA; this allowed us to study in detail its import into mitochondria. Thereby, three characteristics of import were defined: (i) import depended on the presence of nucleoside triphosphates; (ii) involvement of a proteinaceous receptor-like component on the surface of the mitochondria was demonstrated; (iii) insertion into the outer membrane was resolved into at least two distinct steps: specific binding to high-affinity sites and subsequent assembly to the mature form.     

Leydig cell mitoses in human testes bearing early germ cell tumors

Summary Numerous mitoses were noted in testicular tissue from adult men with early germ cell tumors. More than 15 Leydig cells undergoing mitosis were found in the interstitial compartment. The presence of specific crystalline intracytoplasmatic inclusions demonstrated for the first time that differentiated Leydig cells are capable of proliferation. Occasionally cells are difficult to discriminate during mitosis. To establish reference criteria, the light- and electron-microscopic features of the following mitotic cells were examined: Leydig cells, fibroblasts, perivascular cells, peritubular cells, and lymphocytes. Supplementary mitoses in germ cell tumors and in a case of Leydig cell tumor were investigated. In the literature, only single reports of mitoses in Leydig cells are available. The frequent incidence of Leydig cell mitosis in early germ cell tumors may be due to the presence of growth-promoting factors in the testicular tissue.     

Identification of proteins potentially involved in proximal-distal pattern formation in the regenerating forelimb of the newt.

We have used high resolution two-dimensional gel electrophoresis to identify and characterize proteins that may represent products of genes involved in establishing positional information along the proximal-distal axis of the regenerating forelimb of the newt Notophthalmus viridescens. At least 24 proteins have been found whose synthesis and (or) abundance is increased in proximal (midstylopodial) regenerates relative to midzeugopodial (distal) regenerates at either of two regeneration stages, the early dedifferentiation and moderate bud stages. Four of these same proteins show an axial asymmetry at both stages. Ten distal-specific proteins were also identified, although only one was common to both stages. More significantly, 6 of these 34 proteins (molecular masses of 73, 73, 51.5, 44.0, 19.5, and 16.5 kilodaltons and isoelectric points of 6.70, 6.74, 6.0, 6.05, 5.9, and 6.98, respectively) are regulated to proximal levels by treatment of distal regenerates with retinoic acid (RA) at both stages. An additional five are proximalized by RA at only one regeneration stage. Since the effect of RA is to proximalize positional information in blastema cells, these 11 proteins represent gene products that could be involved in a biochemical cascade leading to the establishment of positional information in the regenerating limb along this axis.     

No evidence for linkage of autosomal dominant proximal spinal muscular atrophies to chromosome 5q markers

Summary Two recent articles have reported the linkage of a gene for recessive spinal muscular atrophy (SMA) on the chromosome region 5q11.2–13.3. Our data show no linkage of the dominantly inherited forms of SMA to this chromosome region.     

Treatment with natural human interferon alpha of a CML-patient with antibodies to recombinant interferon alpha-2b

A patient with Philadelphia-chromosome positive chronic myelogenous leukemia developed interferon antibodies on treatment with recombinant interferon alpha-2b. Clinically this event corresponded with progressive disease. No cross-reactivity of antibodies with human leukocyte interferon was found by Western blot. Treatment was switched to human leukocyte interferon with an obvious clinical effect: WBC was reduced and platelet count stabilized, but the effect was transient and no hematologic remission was achieved. Human leukocyte interferon may be an alternative in CML-patients with neutralizing antibodies to recombinant interferon alpha.     

Synthesis patterns of a set of follicle cell proteins in Drosophila melanogaster sibling species

The protein synthesis pattern of a set of stage and tissue specific proteins has previously been described in Drosophila melanogaster. The analysis of this set of follicle cell proteins (Fc proteins) is here extended to cover several sibling species of Drosophila melanogaster, namely D. simulans, D. mauritiana, D. erecta and D. yakuba. Even though a similar set of proteins were synthesized in these species, minor differences in size of the proteins were found between the species. Some of the species exhibited variation within species.     

Therapy for acute myeloid leukemia in 119 adults: a comparison of two treatment protocols

Of 119 patients with acute myeloid leukemia, 69 were treated with Adriamycin, Vincristine and Cytosine Arabinoside (Therapy 1) and 50 with Daunorubicin, Cytosine Arabinoside and 6-Thioguanine (Therapy 2) as well as a consolidation therapy. The maintenance therapy with Cytosine Arabinoside and 6-Thioguanine was the same for both groups. The complete remission rate was 44% for Therapy 1 and 68% for Therapy 2 (p less than 0.05). - The median values for remission duration were 7 and 13 months respectively (p = 0.10); for survival time the median values were 18 and 19 months. These figures show in retrospect that high remission rates can be attained through intensive induction therapy and that longer remission duration is correlated with more aggressive induction therapy. A mild form of maintenance therapy seems to have little effect on the duration of complete remission.     

The influence of water on CO2 exchange in the lichen Parmelia praesignis Nyl.

Net photosynthetic rates for the lichen Parmelia praesignis Nyl. were obtained as a function of 5 light levels, 5 temperature levels, and of water content as thalli dried from saturated conditions. Data are described as second order polynomials in the light, and as saturation curves in the dark. Rates in the light were depressed at high water contents reaching maximal rates between 110% and 180% water content and declining as thalli dried. Physiological parameters were derived from the drying curves to investigate temperature and light interactions. Dark respiration parameters are the maximal rate, the water content where the rate is half-maximal, the water content at which respiration is zero, and the maximal water efficiency. In the light, parameters are the maximal net photosynthetic rate, the water content at the maximal rate, the water compensation point, the maximal water efficiency, and the sensitivity of net photosynthesis to change in water content.Values of half-maximal rate water contents for respiration were found to increase as temperatures increased. The greatest maximal net photosynthetic rate occurred at higher temperatures as the light intensity increased. In the light, maximal water efficiency and the sensitivity to changes in water content were generally maximal at temperatures yielding the greatest maximal net photosynthetic rates.