A factor shed by lymphoblastoid cell lines of HLA-B27 positive patients with ankylosing spondylitis, specifically modifies the cells of HLA-B27 positive normal individuals.

Epstein-Barr virus transformed lymphoblastoid cell lines from HLA-B27 positive individuals with ankylosing spondylitis (B27+AS+) release, into the culture medium, a factor capable of specifically modifying the HLA-B27 positive lymphocytes of normal individuals (B27+AS-); this modification results in a phenotypic change similar to that seen on B27+AS+ lymphocytes. This lymphoblastoid cell line derived factor appears to be physically and functionally similar to a factor present in the culture filtrate of certain Klebsiella isolates. Biogel P-100 chromatography of the material released from the cell line indicated a mol.wt of 25,000-30,000, similar to that of the Klebsiella derived factor. Chromatofocusing on a PBE 94 column revealed that cell line derived factor had an isoelectric point of 5.5 (cf. pI 5.4 for the Klebsiella derived factor). Immunoadsorption experiments suggest that the factor from the B27+AS+ cell line shares antigenic determinants with a cell surface component present on certain Klebsiella isolates. These results will form the basis for future studies on the nature of the interaction between HLA-B27 and certain enteric organisms and their products. A better understanding of this association should elucidate some of the early events in the pathogenesis of the seronegative arthropathies.     

The origins of life -- the 'protein interaction world' hypothesis: protein interactions were the first form of self-reproducing life and nucleic acids evolved later as memory molecules

The 'protein interaction world' (PIW) hypothesis of the origins of life assumes that life emerged as a self-reproducing and expanding system of protein interactions. In mainstream molecular biology, 'replication' refers to the material copying of molecules such as nucleic acids. However, PIW is conceptualized as an abstract communication system constituted by the interactions between proteins, in which 'replication' happens at the level of self-reproduction of these interactions between proteins. Densely concentrated peptide interaction systems may have reproduced and expanded as 'protocell' vesicles surrounded by lipid bi-layer membranes. Protocells led to the emergence of proto-RNA molecules of greater chemical stability which served as chemically differentiated 'memories' of peptide interaction states, thereby facilitating the reproduction and expansion of protocells. Simplification-driven expansion led to the selection of biotic amino acids and the reduction of the typical RNA alphabet to the four usual bases (A, C, G and U). Dense interactions between RNA molecules led to the emergence of the RNA interaction subsystem of the cell, and to the emergence of 'memories' of RNA interactions in the form of DNA molecules with greater chemical stability. The expansion of DNA molecule interactions led to the dense clustering and encapsulation of DNA molecules within the cell nucleus. RNA molecules therefore serve as memories of protein interactions and DNA molecules are memories of RNA interactions. We believe that the PIW hypothesis is more evolutionarily plausible than the mainstream RNA world hypothesis, and has greater explanatory power.     

Extranodal posttransplant plasmacytic hyperplasia with subsequent posttransplant plasmacytic malignancy: six-year interval case report and review of the literature

Posttransplant lymphoproliferative disorders (PTLDs) represent a morphologic, immunophenotypic, and genotypic spectrum of disease. Most recently, Knowles et al divided PTLDs into 3 distinct categories: (1) plasmacytic hyperplasia, (2) polymorphic B-cell hyperplasia and polymorphic B-cell lymphoma, and (3) immunoblastic lymphoma and multiple myeloma. Although one form of PTLD may progress to another form, only 1 previous case has been reported in which multiple myeloma developed 14 months after an original diagnosis of plasmacytic hyperplasia. The type of solid organ transplant was not specified in that case. We report a post--cardiac transplant plasmacytic hyperplasia developing 7 years posttransplant. Six years subsequent to the plasmacytic hyperplasia, the patient developed a posttransplant plasmacytic malignancy, supported by morphology, flow cytometric immunophenotyping, and genotypic studies. Since we have no data to support disseminated bony disease or an abnormal serum protein, we have not used the term "multiple myeloma" for this case.     

Lectins in the unicellular Tetrahymena. II. Impact of nutrition and sugar treatment on anti-lectin binding

Tetrahymena pyriformis GL cells showed partly intracytoplasmic, partly intramembraneous accumulation of lectin-like proteins in conditions of starvation, as demonstrated cytochemically by reaction with antibodies to pea, lens, bean, Datura, and snail lectin. The lectins binding to simple sugars tended to accumulate in the membrane, whereas those capable of interacting with hexosamines in the cytoplasm. While the fluorescence pattern of lectin localization was generally homogeneous in normally nourished cells, it assumed a variegated appearance in starved cells, owing to patching of the membrane, and spot-like accumulation of lectins in the cytoplasm, presumably within membranes of endocytosed vesicles. Snail lectin was an exception, since its distribution remained homogeneous also in conditions of starvation.     

Analysis of the genetic variability of the 1st (CCC/ACC,P52T) and the 10th exons (bp 1012–1704) of the TSH receptor gene in Graves’ disease

We determined the genetic variability of the 1st (CCC/ACC, P52T polymorphic variant) and 10th exons (bp 1012–1704) of the TSH receptor (TSHR) gene in Graves’ disease. A total of 101 Graves’ patients and 163 control subjects were screened. The A253 mutant allele was carried by nine patients with Graves’ disease (8.91%) and 13 control subjects (7.98%) in heterozygous genotype. No significant difference in the frequency of the mutant allele was found between Graves’ patients and control subjects. These results provide evidence that the A253 polymorphism has no genetic relevance in Graves’ disease. Moreover, the DNA nucleotide sequence of 693 bp of the 10th exon (bp 1012–1704) of the TSHR gene was determined in 15 Graves’ patients. Six patients were homozygous for the wild‐type allele and nine were heterozygous for the mutant allele at the 253rd nucleotide of the first exon. No polymorphism was found in the DNA sequences obtained from leukocytes of Graves’ patients, similarly to the sequences obtained from the nine control subjects. None of the nine patients carrying the A253 polymorphism in the 1st exon of the TSHR had polymorphism in the examined part of the 10th exon, including two additional patients whose thyroid tissue was directly analysed. In all likelihood, the polymorphisms of the examined regions of either the 1st or the 10th exon of the THSR gene do not contribute to the genetic susceptibility to Graves’ disease.     

Differentiation of Rhizomucor Species by Carbon Source Utilization and Isoenzyme Analysis

Nineteen Rhizomucor miehei and Rhizomucor pusillus isolates were assayed for their ability to utilize 87 various substrates as a single carbon source. Besides a difference in sucrose utilization, distinctive differences were found in the utilization of glycine, phenylalanine, and β-alanine. Five isoenzyme systems also proved useful for the determination of markers of distinctive value at a species level. Data were used to obtain information about the genetic polymorphism of these species: a high degree of variability was found among the R. pusillus isolates, whereas the group of R. miehei isolates was more homogeneous genetically.     

Distribution and pharmacological characterization of somatostatin receptor binding sites in the sheep brain

Somatostatin binding sites have been localized and quantified in the sheep brain using ¹²⁵I-Tyr₀-DTrp₈-somatostatin, by quantitative high resolution light microscopic autoradiography. Sections were analyzed by densitometry on radioautographic film, and subsequently on slides coated with photoemulsion. Specific somatostatin binding sites were concentrated in the medial habenula, superior colliculus, dorsal motor nucleus of the vagus nerve, inferior olive, spinal trigeminal nucleus, and cerebellum. In competition experiments, octreotide, a sst2/sst3/sst5 selective agonist only partially displaced ¹²⁵I-Tyr₀-DTrp₈-somatostatin in the three cerebellar layers while it was fully active as compared to somatostatin 14 and 28 in the deeper layers of the parietal cortex. Moderate to low somatostatin receptor densities were present in the mesencephalic periaqueductal gray, dorsal raphe, thalamic paraventricular nucleus, interpeduncular nucleus, pineal gland, dorsal tegmental, dorsolateral tegmental and parabrachial nuclei, nucleus of the solitary tract. The distribution of somatostatin binding sites generally correlates with the data obtained on slides dipped in photoemulsion which provided better resolution and more precise localization. In most of the labeled areas, ¹²⁵I-Tyr₀-DTrp₈-somatostatin receptor binding was distributed between both neuropil and perikarya. Perikarya bearing ¹²⁵I-Tyr₀-DTrp₈-somatostatin receptors were observed in areas which did not display detectable binding sites on film such as the preoptic-anterior hypothalamic complex and arcuate nucleus and in the locus coeruleus. In conclusion, the distribution of ¹²⁵I-Tyr₀-DTrp₈-somatostatin binding sites in sheep brain is very reminiscent of other mammals being closer to the human than to rodents.     

CD59 blocks not only the insertion of C9 into MAC but inhibits ion channel formation by homologous C5b-8 as well as C5b-9

Activation of the complement system on the cell surface results in the insertion of pore forming membrane attack complexes (MAC, C5b-9). In order to protect themselves from the complement attack, the cells express several regulatory molecules, including the terminal complex regulator CD59 that inhibits assembly of the large MACs by inhibiting the insertion of additional C9 molecules into the C5b-9 complex. Using the whole cell patch clamp method, we were able to measure accumulation of homologous MACs in the membrane of CD59⁻ human B-cells, which formed non-selective ion channels with a total conductance of 360 ± 24 pS as measured at the beginning of the steady-state phase of the inward currents. C5b-8 and small-size MAC (MAC containing only a single C9) can also form ion channels. Nevertheless, in CD59⁺ human B-cells in spite of small-size MAC formation, an ion current could not be detected. In addition, restoring CD59 to the membrane of the CD59⁻ cells inhibited the serum-evoked inward current. The ion channels formed by the small-size MAC were therefore sealed, indicating that CD59 directly interfered with the pore formation of C5b-8 as well as that of small-size C5b-9. These results offer an explanation as to why CD59-expressing cells are not leaky in spite of a buildup of homologous C5b-8 and small-size MAC. Our experiments also confirmed that ion channel inhibition by CD59 is subject to homologous restriction and that CD59 cannot block the conductivity of MAC when generated by xenogenic (rabbit) serum.     

Differentiation of Rhizomucor species on the basis of their different sensitivities to lovastatin

The opportunistic pathogens Rhizomucor pusillus and Rhizomucor miehei may be agents of frequently fatal mycotic diseases. In the present study, the susceptibilities of 27 clinical and environmental isolates of R. miehei and R. pusillus to lovastatin under different culturing conditions were investigated. Most of the R. miehei strains grew at lovastatin concentrations as high as 64 to 128 microg/ml. In contrast, the inhibitory effect of lovastatin on all of the R. pusillus strains was evident at lovastatin concentrations as low as 1 to 2 microg/ml. A simple and reliable method for species-level differentiation, based on the significantly higher sensitivity of R. pusillus to lovastatin than that of R. miehei, was elaborated. According this, on malt extract agar containing 6 mug of lovastatin/ml, R. pusillus is not able to produce colonies, while R. miehei will form compact colonies.