Cyanophycinase, a peptidase degrading the cyanobacterial reserve material multi-L-arginyl-poly-L-aspartic acid (cyanophycin): molecular cloning of the gene of Synechocystis sp. PCC 6803, expression in Escherichia coli, and biochemical characterization of the purified enzyme

The branched polypeptide multi-L-arginyl-poly-L-aspartic acid, also called cyanophycin, is a water-insoluble reserve material of cyanobacteria. The polymer is degraded by a specific hydrolytic enzyme called cyanophycinase. By heterologous expression in Escherichia coli, a gene encoding cyanophycinase has been identified in the sequenced genome of Synechocystis sp. PCC 6803. The gene, designated cphB, codes for a protein of 29.4 kDa. The high level of expression of active cyanophycinase in E. coli from the Synechocystis gene allowed for its purification to electrophoretic homogeneity. The enzyme, which appears to be specific for cyanophycin, hydrolysed the polymer to a dipeptide consisting of aspartic acid and arginine. Based on inhibitor sensitivity and primary sequence, cyanophycinase appears to be a serine-type exopeptidase related to dipeptidase E [Conlin, C.A., Haakensson, K., Liljas, A. & Miller, C.G. (1994) J. Bacteriol. 176, 166-172].

MAPKAP kinase 2 phosphorylates serum response factor in vitro and in vivo

Several growth factor- and calcium-regulated kinases such as pp90(rsk) or CaM kinase IV can phosphorylate the transcription factor serum response factor (SRF) at serine 103 (Ser-103). However, it is unknown whether stress-regulated kinases can also phosphorylate SRF. We show that treatment of cells with anisomycin, arsenite, sodium fluoride, or tetrafluoroaluminate induces phosphorylation of SRF at Ser-103 in both HeLa and NIH3T3 cells. This phosphorylation is dependent on the kinase p38/SAPK2 and correlates with the activation of MAPKAP kinase 2 (MK2). MK2 phosphorylates SRF in vitro at Ser-103 with similar efficiency as the small heat shock protein Hsp25 and significantly better than CREB. Comparison of wild type murine fibroblasts with those derived from MK2-deficient mice (Mk(-/-)) reveals MK2 as the major SRF kinase induced by arsenite. These results demonstrate that SRF is targeted by several signal transduction pathways within cells and establishes SRF as a nuclear target for MAPKAP kinase 2.

Presence of the proteinase-activated receptor-2 (PAR-2) in human brain tumor cells--trypsin- and SLIGRL-induced calcium response in primary cultured meningiomas

This study focused on proteinase-activated receptor-2 (PAR-2) in primary cultured human meningioma cells. Stimulation of these cells with the serine proteinase trypsin resulted in a dose-dependent transient calcium response. Since the specific PAR-2 agonist peptide SLIGRL also induced [Ca2+]i mobilization in human meningioma cells and successive application of SLIGRL and trypsin elicited no new calcium signal we conclude that trypsin-induced calcium signaling is mediated by PAR-2 in human meningioma cells. To our knowledge, this is the first report describing functional PAR-2-type receptors in human brain tumor cells.

Sequence information within proteasomal prosequences mediates efficient integration of beta-subunits into the 20 S proteasome complex

The maturation of proteases is governed by prosequences. During the biogenesis of the highly oligomeric eukaryotic 20 S proteasome five different prosequence-containing subunits have to be integrated and processed either by autocatalysis or by neighbouring subunits. To analyse the functional impact of proteasomal prosequences during complex formation, the propeptide of the facultative subunit beta1i/LMP2 was truncated to nine amino acid residues or completely deleted. Additionally, the charged residues within the truncated beta1i/LMP2 version were replaced by neutral residues. While deletion did not affect subunit incorporation, the presence of charged residues within the truncated version of the LMP2 propeptide diminished incorporation efficiency, an effect that was restored upon replacement of the charged amino acids against neutral components. During immunoproteasome formation, incorporation and processing of inducible proteasome beta-subunits are cooperative processes. We demonstrate a linear correlation of the levels of beta2i/MECL1 and beta1i/LMP2 within 20 S proteasomes, suggesting a physical interaction to be the molecular basis for the biased incorporation of both subunits. In the absence of beta5i/LMP7, precursor complexes containing unprocessed beta1i/LMP2 accumulated. The contribution of beta5i/LMP7 on the cooperative formation of a homogeneous population of immunoproteasome is therefore most likely based on an acceleration of the beta1i/LMP2 and potentially of beta2i/MECL1 processing kinetics.

PAR 1-type thrombin receptors are involved in thrombin-induced calcium signaling in human meningioma cells

Thrombin is known to play a role as regulator in tumor spreading and tumor growth. Proteinase-activated receptor 1 (PAR 1)-type thrombin receptors were identified in different cancer cells including human glioblastoma cells. Thus a function of PAR 1 in brain tumors may be suggested. In this study, the presence of PAR 1-type thrombin receptors was investigated in primary cell cultures established from operated human meningiomas from two 59- and 79-year-old women. Characterization of PAR 1 on binding level was performed using immunofluorescence studies with the monoclonal anti-PAR 1 antibody Mab 61-1 directed against a domain in the NH2-terminus of PAR 1. These binding sites constitute functional thrombin receptors that are involved in thrombin-induced signaling in human meningioma cells as demonstrated by investigation of alpha-thrombin- and PAR 1-activating hexapeptide (TRAP-6)-induced [Ca2+]i mobilization. To our knowledge, this is the first report demonstrating thrombin-induced intracellular signaling in human meningioma cells mediated by the PAR 1-type thrombin receptor.

Oncocytic (Hürthle cell) tumors of the thyroid: distinct growth patterns comparedẁith clinicopathological features

Neoplastic growth results from cell production that exceeds cell loss. We registered mitotic and apoptotic indices (MI and AI) in 97 immunohistochemically verified oncocytic (Hürthle cell) tumors of the thyroid (OT; 50 adenomas [OA], 20 atypical adenomas [aOA], and 27 carcinomas [OC]) and compared these kinetic data with histological diagnoses and other parameters. MI, although very low in all, was significantly higher in carcinomas than in adenomas. Conversely, AI did not differ as much among the 3 groups. This indicates that the magnitude of cell deletion did not play a prominent role in determining the disparate growth of the 3 types of oncocytic tumors. Cluster analysis with MI and AI per case as variables revealed the existence of 3 groups of neoplasms with highly distinct growth characteristics: (1) near-steady state (n = 78, all diagnostic categories represented); (2) progressive (n = 9, mostly carcinomas); and (3) regressive (n = 10, mostly adenomas). MI distinguished between histologically benign and malignant with the greatest discriminant power of the variables tested. Proliferative indices should thus be included in the differential diagnostic evaluation of oncocytic thyroid tumors. Our study also suggests that invasiveness and growth are 2 diverging properties of carcinomas.

ICOS is an inducible T-cell co-stimulator structurally and functionally related to CD28

The T-cell-specific cell-surface receptors CD28 and CTLA-4 are important regulators of the immune system. CD28 potently enhances those T-cell functions that are essential for an effective antigen-specific immune response, and the homologous CTLA-4 counterbalances the CD28-mediated signals and thus prevents an otherwise fatal overstimulation of the lymphoid system. Here we report the identification of a third member of this family of molecules, inducible co-stimulator (ICOS), which is a homodimeric protein of relative molecular mass 55,000-60,000 (M(r) 55K-60K). Matching CD28 in potency, ICOS enhances all basic T-cell responses to a foreign antigen, namely proliferation, secretion of lymphokines, upregulation of molecules that mediate cell-cell interaction, and effective help for antibody secretion by B cells. Unlike the constitutively expressed CD28, ICOS has to be de novo induced on the T-cell surface, does not upregulate the production of interleukin-2, but superinduces the synthesis of interleukin-10, a B-cell-differentiation factor. In vivo, ICOS is highly expressed on tonsillar T cells, which are closely associated with B cells in the apical light zone of germinal centres, the site of terminal B-cell maturation. Our results indicate that ICOS is another major regulator of the adaptive immune system.

The steroid hormone 20-hydroxyecdysone enhances neurite growth of Drosophila mushroom body neurons isolated during metamorphosis

Mushroom bodies (MBs) are symmetrically paired neuropils in the insect brain that are of critical importance for associative olfactory learning and memory. In Drosophila melanogaster, the MB intrinsic neurons (Kenyon cells) undergo extensive reorganization at the onset of metamorphosis. A phase of rapid axonal degeneration without cell death is followed by axonal regeneration. This re-elaboration occurs as levels of the steroid hormone 20-hydroxyecdysone (20E) are rising during the pupal stage. Based on the known role of 20E in directing many features of CNS remodeling during insect metamorphosis, we hypothesized that the outgrowth of MB axonal processes is promoted by 20E. Using a GAL4 enhancer trap line (201Y) that drives MB-restricted reporter gene expression, we identified Kenyon cells in primary cultures dissociated from early pupal CNS. Paired cultures derived from single brains isolated before the 20E pupal peak were incubated in medium with or without 20E for 2-4 d. Morphometric analysis demonstrated that MB neurons exposed to 20E had significantly greater total neurite length and branch number compared with that of MB neurons grown without hormone. The relationship between branch number and total neurite length remained constant regardless of hormone treatment in vitro, suggesting that 20E enhances the rate of outgrowth from pupal MB neurons in a proportionate manner and does not selectively increase neuritic branching. These results implicate 20E in enhancing axonal outgrowth of Kenyon cells to support MB remodeling during metamorphosis.

Cellular kinetic differences between Hodgkin's and anaplastic large cell lymphomas: relation to the expression of p34cdc2 and cyclin B-1

Our study was designed to compare cellular kinetic parameters of classical Hodgkin's disease (HD) with those of anaplastic large cell lymphomas (ALCL-C, common type; and ALCL-HL, Hodgkin's like), with a particular focus on the G2/M transition. These disorders share some phenotypic properties, e.g., CD30 positivity of putative neoplastic cells. The percentages of cells expressing p34cdc2 (p34) and cyclin B-1 (cyclin-B), which form a complex (maturation/mitosis promoting factor, MPF) regulating the G2-M phases of the cell cycle, were also registered. Highly significant differences between HD and ALCL-C were recognized: a) in HD, evidence for abortive mitosis (i.e., difficulty to proceed beyond the metaphase stage) and consequent multinucleation and/or deletion of CD30+ cells was prominent, in contrast to ALCL-C. This was associated with a markedly lower fraction of large atypical cells (LAC) expressing cyclin-B in the cytoplasm and the nucleus (C + N) in HD than in ALCL-C; b) the extent of multinucleation of CD30+ cells in HD, but not in ALCL-C, was correlated with the %p34+ LAC; c) the proportions of LAC expressing p34 and/or cyclin-B (C) were positively related to the percentages of cyclin-B (C + N)+ LAC in ALCL-C but not in HD; d) in HD, in contrast to ALCL-C, the size of the fraction of cyclin-B (C + N)+ LAC did not correlate with the ana/telophase indices (ATI, reflecting successful completion of mitosis) and the magnitude of cell loss; e) in ALCL-C, the percentages of p34+ LAC were positively correlated with ATI or the degree of CD30+ cell deletion, but inversely in HD. With regard to all parameters mentioned above, ALCL-HL tended to take an intermediate position between HD and ALCL-C, but sided more with the latter. In conclusion, our present results suggest a derangement of MPF kinetics and functions that is more profound in HD than in ALCL-C.

The monoclonal antibody AS02 recognizes a protein on human fibroblasts being highly homologous to Thy-1

Recently, we described a novel fibroblast-restricted monoclonal antibody (mAb AS02) that recognizes a membrane-bound antigen. Characterization and isolation of the corresponding antigen showed that mAb AS02 recognized a protein on human fibroblasts that is highly homologous or identical to human Thy-1 antigen (CD90). Partial amino acid sequencing of the corresponding mAb AS02 antigen and comparison with known proteins revealed a 100% homology of the sequenced peptides to the human Thy-1 antigen. Cross-immunodepletion studies with mAb AS02 and an anti-Thy-1 antibody confirmed these results. Utilizing two-dimensional (2D) gel electrophoresis of fibroblast cell extracts and purified antigen, mAb AS02 and the anti-Thy-1-antibody recognized identical protein spots. Furthermore, we demonstrated many identical biochemical properties of the corresponding AS02 antigen and Thy-1 antigen, such as the molecular weight of the core protein and deglycosylation products and the detection of a GPI anchor. In functional assays, the attachment of fibroblasts to collagen I and fibronectin was increased after incubation of fibroblasts with mAb AS02. Therefore, the Thy-1 antigen appears to be involved in the regulation of the adherence of human dermal fibroblasts.

Mammalian protein homologous to VAT-1 of Torpedo californica: isolation from Ehrlich ascites tumor cells, biochemical characterization, and organization of its gene

Recently, interest has focused on the human gene encoding the putative protein homologous to VAT-1, the major protein of the synaptic vesicles of the electric organ of the Pacific electric ray Torpedo californica, after it has been localized on chromosome locus 17q21 in a region encompassing the breast cancer gene BRCA1. Chromosomal instability in this region is implicated in inherited predisposition for breast and ovarian cancer. Here we describe isolation and biochemical characterization of a mammalian 48 kDa protein homologous to the VAT-1 protein of Torpedo californica. This VAT-1 homolog was isolated from a murine breast cancer cell line (Ehrlich ascites tumor) and identified by sequencing of cleavage peptides. The isolated VAT-1 homolog protein displays an ATPase activity and exists in two isoforms with isoelectric points of 5.7 and 5.8. cDNA was prepared from Ehrlich ascites tumor cells, and the murine VAT-1 homolog sequence was amplified by polymerase chain reaction and partially sequenced. The known part of the murine and the human translated sequences share 97% identity. By Northern blots, the size of the VAT-1 homolog mRNA in both murine and human (T47D) breast cancer cells was determined to be 2.8 kb. Based on the presented data, a modified gene structure of the human VAT-1 homolog with an extended exon 1 is proposed. VAT-1 and the mammalian VAT-1 homolog form a subgroup within the protein superfamily of medium-chain dehydrogenases/reductases.

A novel protein complex involved in signal transduction possessing similarities to 26S proteasome subunits

A novel protein complex has been identified in human cells that has a molecular mass of approximately 450 kDa. It consists of at least eight different subunits including JAB1, the Jun activation-domain binding protein 1, and Trip15, the thyroid hormone receptor-interacting protein 15. The purified complex contains COP9 and COP11 protein homologs and is very similar, if not identical, to the plant COP9 complex involved in light-mediated signal transduction. The isolated JAB1-containing particle has kinase activity that phosphorylates IkappaBalpha, the carboxy terminus of p105, and Ser63 and/or Ser73 of the amino-terminal activation domain of c-Jun. The phosphorylation of c-Jun requires the carboxy terminus of the protein containing the DNA binding and dimerization domains. Three subunits of the new complex--Sgn3, Sgn5/JAB1, and Sgn6--exhibit sequence similarities to regulatory components of the 26S proteasome, which could indicate the existence of common substrate binding sites. Immunofluorescence staining reveals that the new complex shows a subcellular distribution similar to that of the 26S proteasome. The functional relationship of the two particles in regulating transcriptional activity is discussed. Considering the putative role of the complex in signal transduction and its widespread occurrence, we suggest the name JAB1-containing signalosome.

Growth patterns of diffuse non-Hodgkin's lymphomas estimated from mitotic and apoptotic indices

Growth rates of neoplasms could be calculated only on the basis of mitotic and apoptotic indices (MI and AI, respectively), assessed on tissue sections, if the duration of mitosis and apoptosis (Tm and Ta, respectively) in vivo were known. For humans, this is practically never the case. What use then can be made of MI and AI to arrive at a relative, crude estimate of the state of growth? As a model system to study this problem, we chose diffusely growing stage I + II non-Hodgkin's lymphomas (dNHL, n = 94). Cluster analysis revealed the existence of 3 highly distinct groups of dNHL (clusters I, II and III) in the MI vs. AI per case plot, with a roughly linear relation between both parameters. Most nosologic entities defined by the REAL classification comprise cases that were represented in more than one cluster. We adopted the simple formula GI (growth index) = XMI - AI, where X (= Ta/Tm) remains to be evaluated. Based on the assumption that spontaneous regressions of dNHL are rare but do occur, we estimated that X = 2 or, possibly, 3 are best fits for the pooled dNHLs studied. With the assumption of X = 2, (i) 2MI - AI gave relatively lower values for dNHL than proliferative indices such as %Ki-67+ cells; (ii) values for 2MI/AI per cluster showed a pattern inverse to that for %bcl-2+ cells; and (iii) a plot of 2MI - AI vs. 2MI/AI per case allowed the recognition, especially among NHLs with a low cell turnover, of cases where accumulation of presumably longer-lived cells is an important factor in determining growth.

Export of importin alpha from the nucleus is mediated by a specific nuclear transport factor

NLS proteins are transported into the nucleus by the importin alpha/beta heterodimer. Importin alpha binds the NLS, while importin beta mediates translocation through the nuclear pore complex. After translocation, RanGTP, whose predicted concentration is high in the nucleus and low in the cytoplasm, binds importin beta and displaces importin alpha. Importin alpha must then be returned to the cytoplasm, leaving the NLS protein behind. Here, we report that the previously identified CAS protein mediates importin alpha re-export. CAS binds strongly to importin alpha only in the presence of RanGTP, forming an importin alpha/CAS/RanGTP complex. Importin alpha is released from this complex in the cytoplasm by the combined action of RanBP1 and RanGAP1. CAS binds preferentially to NLS-free importin alpha, explaining why import substrates stay in the nucleus.

[3 siblings with identical, rare pneumopathy]

Pulmonary alveolar microlithiasis was found in three siblings. Only the youngest of them, a former smoker, developed endstage lung disease. The other two are asymptomatic with normal lung function despite impressive changes on all chest radiographs. The role of smoking in perpetuating microlithiasis and furthering the progression of this disease is discussed.

Cell kinetics, morphology, and molecular IgVH gene rearrangements in Hodgkin's disease

The present study dealt with the question of whether any cellular kinetic patterns correlate with clonal rearrangement of the IgVH gene as revealed by polymerase chain reaction on DNA extracted from lymph nodes with classical Hodgkin's disease (HD) and/or from single CD30+ cells (Hodgkin [H] and Reed-Sternberg [RS] cells). In 15/4 cases with H-RS cells of B or Null phenotype, signs of such monoclonality could be detected (group I) but not in the others (group II). CD30+/H-RS cells in group I differed slightly but significantly from those in group II in that they a) exhibited a larger fraction of cells attaining the anaphase/telophase stage of mitosis, and b) produced relatively more mononucleated cells (H) at the expense of multinucleated (RS) cells. In addition, reactive lymphoid cell (CD30-) infiltrates were considerably less dense in group I that in group II. These findings suggest that the cytokinesis of H-RS cells in group I was moderately more efficient than in group II. However, signs of monoclonality were not associated with the normalization of the mitotic process, which also proved to be disturbed in group I.

[Cervix cytology: Cervex Brush versus conventional cotton swab]

Cervical smears should contain endocervical cells to be accepted as representative for a cytologic diagnosis. In this prospective study with 200 women we compared cytologic specimens obtained by Cervex-Brush (100 women) or by conventional cotton-swab (100 women) technique. The incidence of smears containing cylindrical and metaplastic cells was 85% in the Cervex-Brush group and only 58% in the cotton-swab group. We believe that the application of the Cervex-Brush or a similar instrument should result in fewer repeat smears and fewer false-negative smears and thus in an improvement of the cervical cytology.

Cellular kinetic and phenotypic heterogeneity in and among Burkitt's and Burkitt-like lymphomas

This study asks whether the known genotypic heterogeneity within and between endemic or sporadic Burkitt's lymphomas (eBLs and sBLs, n = 10 each), and Burkitt-like lymphomas (BLLs, n-12), is reflected in divergent cytokinetics and related immunophenotypes. There was strong evidence that eBL and BLL grow markedly faster than sBL, as shown by differences in mitotic and apoptotic indices. Furthermore, in BLL, the median percentage of neoplastic cells immunoreactive for the bcl-2 protein was much higher than that observed in eBL and sBL. The reverse was true for the median fraction of cells containing c-myc protein. In eBL and sBL, the median fraction of bcl-6 protein-positive cells reached values above 50 per cent, while cells of 8/12 BLLs did not contain detectable amounts of this protein. This observation indicates that in this respect, eBL and sBL resemble normal germinal centres of lymphatic tissue much more than do BLL. Evidence for infection of neoplastic cells by the Epstein-Barr virus (EBV) was observed in 9/10 cases of eBL and in 3/10 of sBL, but not in BLL. EBV-positive lymphomas were associated with distinctly lower apoptotic indices and smaller median percentages of bcl-6-positive cells than EBV-negative tumours.

Purification, structural analysis, and function of natural ATAC, a cytokine secreted by CD8(+) T cells

Recently, we identified a novel putative human cytokine expressed by activated CD8(+) T cells, which was designated ATAC (activation-induced, T cell-derived, and chemokine-related; the same molecule has been identified independently as lymphotactin and single cysteine motif-1). In this report, we provide evidence that ATAC is a secreted 93-amino acid protein that is generated from its precursor by proteolytic cleavage between Gly21 and Val22. An estimated 60% of ATAC (Val22-Gly114) is secreted as an unmodified protein with a molecular mass of 10,271.72 Da (apparent molecular mass of 12 kDa in SDS-polyacrylamide gel electrophoresis) and in which Cys32 and Cys69 are linked by a disulfide bridge. Unmodified ATAC is a cationic protein with a pI of 11.35 and is capable of binding to heparin. Some 40% of ATAC is O-glycosylated within 25 min of synthesis, giving rise to the appearance of a homogeneous 15-kDa (minor fraction) and a heterogeneous, terminally sialylated 17-19-kDa (major fraction) protein species in SDS-polyacrylamide gel electrophoresis. The secretion of all ATAC protein variants is completed within 30-40 min of synthesis. In terms of function, various ATAC protein forms were consistently ineffective in chemotaxis assays. In contrast, both purified natural ATAC and a chemically synthesized aglycosyl analog induced locomotion (chemokinesis) in purified CD4(+) and CD8(+) T cell populations at 400 ng/ml.

Mitotic activity and nuclear DNA damage of large cells in Hodgkin's disease: comparison with the expression of p53 and bcl-2 proteins and the presence of Epstein-Barr virus

The roles of the bcl-2 and p53 proteins in Hodgkin's disease (HD) are poorly understood. We therefore compared their detected presence in Hodgkin and Reed-Sternberg/large atypical (H-RS/LA) cells immunohistochemically with the percentages of these cells double-labeled for CD30 and DNA strand breaks (DNA fragmentation index, DFI); mitotic indices (MI); and the EBV infection status. We found a highly significant inverse correlation between the fractions per case of H-RS/LA cells expressing bcl-2/p53 proteins and the DFI of CD30+ elements. No marked effect of these two oncoproteins on MI was noticed, although these parameters and DFI of CD30+ cells were linearly related. EBV infection of H-RS/LA cells exerted only a limited effect on the parameters tested. The results of this study suggest that overexpressed bcl-2 and, to some extent, p53 proteins in H-RS/LA cells of HD primarily counteract deletion of these cells.

Analysis of mammalian 20S proteasome biogenesis: the maturation of beta-subunits is an ordered two-step mechanism involving autocatalysis

Maturation of eukaryotic 20S proteasomes involves the processing of beta-subunits by limited proteolysis. To study the processing mechanism we analysed different point mutations of the beta-subunit LMP2 in transfected human T2 cells. Here we show that the presence of the intact Gly-1Thr1 consensus motif and Lys33 are essential for correct processing. Mutation of Thr1, the active site residue in mature subunits, or of Lys33, results in complete inhibition of processing at the consensus site. In addition, proprotein processing in vitro of wild-type LMP2, incorporated in immature 16S precursor complexes, can be blocked by a proteasome-specific inhibitor. While the processing of inhibitor-treated wild-type proprotein was completely prevented, the site-directed mutagenesis of LMP2 results in processing intermediates carrying an extension of 8-10 residues preceding Thr1, suggesting an additional cleavage event within the prosequence. Furthermore, exchange of mammalian prosequences interferes with processing efficiency and suggests subunit specificity. Based on our data we propose a model for self-activation of proteasomal beta-subunits in which residue Thr1 serves as nucleophile and Lys33 as proton donor/acceptor. We provide evidence that subunit processing of mammalian beta-subunits proceeds via a novel ordered two-step mechanism involving autocatalysis.

Stage-related differences of mitotic and apoptotic indices, and bcl-2 protein expression in diffusely growing non-Hodgkin's lymphomas

The present study examined whether growth characteristics of diffusely growing non-Hodgkin's lymphomas (NHL) may differ as a function of stage. Among 105 NHL of various types and sub-types (REAL [Revised European-American Lymphoma] classification), localized (Ann Arbor pathologic stages I + II) lymphomas exhibited clearly higher indices for mitotic activity, apoptosis and cell turnover, as well as a significantly lower percentage of cells containing immunohistochemically detectable bcl-2 protein, than disseminated (stages III + IV) NHL. A similar pattern emerged when high-grade (Kiel classification) lymphomas only were evaluated. Low-grade NHL showed analogous, but less marked, stage-dependent characteristics, with the exception of median percentages of bcl-2+ cells, which remained comparable in all stages. Our findings are consistent with the notion that dissemination of diffusely growing NHL is usually associated with reduced cell turnover and, in high-grade lymphomas, with the generation of longer-lived cells.

Atypical cells in effusions: diagnostic value of cell image analysis combined with immunocytochemistry

The reliable identification of tumor cells in populations of atypical cells occurring in body cavity effusions is a well-known diagnostic problem. In order to improve tumor cell detection and to predict disease progression, we developed a cell scoring strategy based on a combination of DNA cytophotometry and immunocytochemistry. For this purpose, morphologically atypical cells obtained from 33 effusion samples were submitted to DNA content analysis and tested for Ber-EP4 immunoreactivity. It turned out that elevated DNA content alone has a low specificity (true negative ratio) and sensitivity (true positive ratio) in predicting disease outcome, whereas Ber-EP4 immunoreactivity alone has a high specificity (100%) but a low sensitivity (56%). In contrast, the use of a scoring system combining the two techniques and relating scores to the previous disease state and the cytomorphology of the atypical cells results in highly specific and sensitive prediction of the disease outcome. We therefore suggest that this approach is a valuable tool for reliably identifying tumor cells in effusions containing populations of cytologically suspect cells.

Extensive extramedullary hematopoiesis in a thyroid nodule

We describe a case of extramedullary hematopoiesis in a hyperplastic thyroid nodule from a patient with primary myelofibrosis. The presence of extensive extramedullary hematopoiesis in the thyroid gland was suspected as a result of fine-needle aspiration cytologic examination and was confirmed by histo- and immunomorphologic examination of the resected nodule. The diagnosis of myelofibrosis was established on the basis of clinical findings, hematologic laboratory results, and bone marrow morphologic characteristics.

Importin provides a link between nuclear protein import and U snRNA export

Importin-alpha mediates nuclear protein import by binding nuclear localization signals and importin-beta. We find approximately 30% of SRP1p, the yeast importin-alpha, in a nuclear complex with the Saccharomyces cerevisiae nuclear cap-binding protein complex (CBC). Similarly, a large fraction of Xenopus CBC is associated with importin-alpha in the nucleus. CBC promotes nuclear export of capped U snRNAs and shuttles between nucleus and cytoplasm. The CBC-importin-alpha complex binds specifically to capped RNA, suggesting that CBC might shuttle while bound to importin-alpha. Strikingly, importin-beta binding displaces the RNA from the CBC-importin-alpha complex. Thus, the commitment of CBC for nuclear reentry triggers the release of the export substrate into the cytoplasm. We provide evidence for a mechanism that ensures that importin-mediated RNA release is a specifically cytoplasmic event.

Abortive mitoses and nuclear DNA fragmentation in CD30+ large cells of Hodgkin's disease

This study was undertaken to better comprehend the reasons for the scarcity of Hodgkin and Reed-Sternberg (H-RS) cells in Hodgkin's disease (HD) despite their expression of "proliferation-associated antigens". To this end, we assessed the relative frequency of mitotic phases and nuclear damage (detected by in situ end-labeling of DNA strand breaks) in CD30+ large cells of nodular sclerosis and mixed cellularity HD. Our results show that a) most CD30+ cells in HD exhibit abortive mitoses, with a highly significant arrest at the metaphase-ana/telophase transition, and b) many of these elements, i.e. mainly H-RS cells, show fragmentation of nuclear DNA, suggesting imminent or actual death. Percentages of CD30+ cells that entered mitosis and those with DNA strand breaks were of a similar order of magnitude and correlated significantly in a linear fashion. These findings are consistent with the concept that cell deletion is the major cause of the paucity of H-RS cells in HD.

Nonasbestos ferruginous bodies in sputum from a patient with graphite pneumoconiosis: a case report

BACKGROUND

Inhalation of graphite dust can cause lung disease, mostly in the form of mixed-dust pneumoconiosis in individuals working in the metallurgic industry or graphite mines. The morphologic landmark of graphite pneumoconiosis is nonasbestos ferruginous bodies with a black graphite core.

CASE

In the sputum of an 81-year-old male, characteristic nonasbestos ferruginous bodies were identified. The occupational history confirmed long exposure to natural graphite in metallurgy.

CONCLUSION

By the identification of typical ferruginous bodies, the screening of sputum smears may confirm the clinical and radiologic suspicion of pneumoconiosis and may contribute to determining its causes.

Purification and characterization of the hydrogenase from Thiobacillus ferrooxidans

Hydrogenase of Thiobacillus ferrooxidans ATCC 19859 was purified from cells grown lithoautotrophically with 80% hydrogen, 8.6% carbon dioxide, and 11.4% air. Hydrogenase was located in the 140,000 x g supernatant in cell-free extracts. The enzyme was purified 7.3-fold after chromatography on Procion Red and Q-Sepharose with a yield of 19%, resulting in a 85% pure preparation with a specific activity of 6.0 U (mg protein)-1. With native PAGE, a mol. mass of 100 and 200 kDa was determined. With SDS-PAGE, two subunits of 64 (HoxG) and of 34 kDa (HoxK) were observed. Hydrogenase reacted with methylene blue and other artificial electron acceptors, but not with NAD. The optimum of enzyme activity was at pH 9 and at 49 degrees C. Hydrogenase contained 0.72 mol nickel and 6.02 mol iron per mol enzyme. The relationship of the T. ferrooxidans hydrogenase to other proteins was examined. A 9.5-kb EcoRI fragment of T. ferrooxidans ATCC 19859 hybridized with a 2.2-kb XhoI fragment from Alcaligenes eutrophus encoding the membrane-bound hydrogenase. Antibodies against this enzyme did not react with the T. ferrooxidans hydrogenase in Western blot analysis. The N-terminal amino acid sequence (40 amino acids) of HoxK was 46% identical to that of the hydrogen sensor HupU of Bradyrhizobium japonicum and 39% identical to that of the HupS subunit of the Desulfovibrio baculatus hydrogenase. The N-terminal sequence of 20 amino acids of HoxG of T. ferrooxidans was 83.3% identical to that of the 60-kDa subunit. HupL, of the hydrogenase of Anabaena sp. Sequences of ten internal peptides of HoxG were 50-100% identical to the respective sequences of HupL of the Anabaena sp. hydrogenase.

Growth vs. DNA strand breaks in Hodgkin's disease: impaired proliferative ability of Hodgkin and Reed-Sternberg cells

We re-appraised the cell renewal pattern in Hodgkin's disease (HD), considering that most, though not all, Hodgkin/Reed-Sternberg (H-RS) cells exhibit abortive mitoses and that a substantial fraction of these exhibits DNA damage suggestive of imminent or actual cell death. Using combined immunohistochemistry and in situ end-labeling to detect strand breaks, the percentage per case of CD30+ (mainly H-RS) cells with DNA fragmentation (DNA fragmentation index [DFI]) was estimated. For each case, we registered the mitotic index (MI) of CD30+ cells and the percentage of Ki-67+ atypical large cells. To quantify the sum of our parameters for mitosis, whether successful or not, and DNA damage, we introduced the kinetic event index (KEI = MI + DFI). Only DFI and KEI distinguished significantly between mixed cellularity and nodular sclerosis HD. The values for MI and DFI, and therefore for KEI, CD30+ and CD30- small lymphoid cells were proportional. The percentages of Ki-67+ large atypical cells (median 50%) did not correlate significantly with either MIs or DFIs of CD30+ cells. Cluster analysis revealed the existence, independent of histological subtype, of 2 large groups of HD with different KEIs. Our findings suggest that cell deletion plays an important role in HD. Further, it appears that proliferation-associated antigens in H-RS cells do not reflect successful cell production in this disorder.

A third interferon-gamma-induced subunit exchange in the 20S proteasome

The 20S proteasome is a protease complex of functional importance for antigen processing. Two of the 14 proteasome subunits, delta and MB1, can be replaced by the major histocompatibility complex (MHC)-encoded and interferon-gamma (IFN-gamma)-inducible subunits LMP2 and LMP7, respectively. LMP2 and LMP7 alter the cleavage site specificity of the 20S proteasome and are required for the efficient generation of T cell epitopes from a number of viral proteins and for optimal MHC class I cell surface expression. We compared the 20S proteasome subunit pattern from IFN-gamma-induced and non-induced mouse fibroblasts on two-dimensional gels and identified a third subunit exchange by microsequencing: the non-MHC-encoded subunit MECL-1 is induced by IFN-gamma and replaces a sofar barely characterized beta subunit designated 'MC14'. In analogy to LMP2 and LMP7, MECL-1 may be functional in MHC class I-restricted antigen presentation.

20S proteasome from LMP7 knock out mice reveals altered proteolytic activities and cleavage site preferences

20S proteasomes of tissues from LMP7 knock out mice which show reduced MHC class I restricted antigen presentation were analyzed with regard to their subunit composition, peptide hydrolyzing activity and their ability to cleave a synthetic 25-mer polypeptide. LMP7 deficiency results in an enhanced incorporation of subunit MB1 and in a 2-3.8-fold increase in Vmax for the Suc-LLVY-MCA hydrolyzing activity. Since LMP7 deficiency also affects the cleavage site preference of 20S proteasomes the reduced MHC class I antigen presentation of LMP7 knock out mice is most likely due to an impairment in peptide generation.

Intravesical versus intravesical plus intradermal bacillus Calmette-Guerin: a prospective randomized study in patients with recurrent superficial bladder tumors

PURPOSE

Intravesical instillation of bacillus Calmette-Guerin (BCG) induces various immunological reactions and decreases the recurrence rate of superficial bladder tumors. To determine whether additional immune stimulation with concomitant intradermal BCG applications could further lower the recurrence rate, 154 patients with superficial bladder tumors at high risk for recurrence were randomized to receive either 6 intravesical instillations of 120 mg. Pasteur strain BCG alone or combined with intradermal application.

MATERIALS AND METHODS

A total of 76 patients received intravesical and intradermal BCG, while 78 received intravesical BCG only. Median followup was 41 months (range 2 to 89) and 36 months (range 2 to 86), respectively. Both treatment groups were comparable regarding patient age and number of previous transurethral bladder tumor resections, as well as tumor recurrence rate, stage and grade before BCG therapy.

RESULTS

A highly significant decrease in the monthly tumor recurrence rate was observed in both arms after BCG compared to the pretreatment recurrence rates (p < 0.0001). Recurrence rate decreased from 0.73 +/- 1.07 (standard deviation) to 0.06 +/- 0.13 in the combined treatment group and from 0.71 +/- 0.90 to 0.074 +/- 0.17 in the intravesical treatment only group. However, we were unable to find any difference between the 2 groups regarding interval to initial recurrence or recurrence rates after BCG treatment. Changes in the purified protein derivative skin test performed before and after BCG therapy were not useful to predict response to treatment because 44% of our patients already had a positive test before treatment. Also, interpretation of the skin test was difficult and not always reliable. In the multivariate analysis, however, fever was an important prognostic factor. Patients with increased body temperature greater than 37.5C had a significantly lower recurrence rate than those without fever (37.5C or less) after BCG instillation (p = 0.009). Moreover, fever after BCG instillation was observed significantly more frequently in patients with a positive purified protein derivative skin test before treatment (p = 0.021).

CONCLUSIONS

The therapeutic benefit from intravesical BCG apparently was not substantially improved by simultaneous intradermal BCG vaccination. Fever following intravesical BCG instillation is an important prognostic factor regarding superficial bladder tumor recurrence. Fever occurs predominantly in patients who were previously sensitized to mycobacteria (by BCG vaccination or infection) as shown by a positive pretreatment purified protein derivative skin test. This finding suggests that previously sensitized patients respond significantly better to a single course of intravesical BCG.

Low versus high cell turnover in diffusely growing non-Hodgkin's lymphomas

Cell loss, perhaps as important as cell production in determining the size of an expanding cell population, has not usually been registered in quantitative cellular kinetic analyses of neoplastic disorders. The present retrospective study on various types and subtypes of non-Hodgkin's lymphomas (NHLs; n = 170) was designed to test the usefulness of a novel additional parameter, the 'turnover index' (TI), which is the sum per case of the mitotic index and the apoptotic index. Results document that TIs clearly distinguished between categories and subtypes of NHLs according to the Kiel classification. Cluster analysis of TIs plotted against the percentage of Ki-67-positive cells per case revealed that about one-third of the high-grade malignancy lymphomas actually belonged to the low-turnover lymphomas. Overall survival was longer in the low- than in the high-turnover group of lymphomas. Assessment of TIs can, for practical diagnostic purposes, be replaced by counting mitotic figures and apoptotic cells in several high-power fields. The TI concept may help to interpret the kinetics of NHLs in terms of accumulation vs. proliferation of cells.

Incorporation of major histocompatibility complex--encoded subunits LMP2 and LMP7 changes the quality of the 20S proteasome polypeptide processing products independent of interferon-gamma

The 20S proteasome is the enzyme complex responsible for the processing of antigens bound by major histocompatibility complex class I molecules. The role of the interferon-gamma (IFN-gamma)-inducible proteasome subunits LMP2 and LMP7 in this process is, however, still controversial. We have studied the effects of IFN-gamma-independent LMP incorporation on the quality of peptides processed from the murine cytomegalovirus IE pp89 25-mer polypeptide substrate through dual cleavages by 20S proteasomes. The incorporation of a single LMP subunit or both LMP2 and LMP7 induces changes in 20S proteasome subunit stoichiometry, alters its cleavage site preference and in consequence, the quality of the generated peptides. When the several hydrolytic activities are tested with short fluorogenic peptide substrates, the Vmax, S0.5 (Km), or both values of 20S proteasomes are altered, depending on the combination of LMP. There exists, however, no obvious correlation between the observed changes in hydrolytic activities against short fluorogenic peptides and the changes in dual cleavage site usage within the 25-mer polypeptide substrate. As judged from the calculated Hill coefficients, the presence of both LMP subunits induces a drastic increase in positive cooperativity between the proteasome subunits.

Presence of the bcl-2 protein and apoptosis in non-Hodgkin lymphomas with diffuse growth pattern

In an attempt to further clarify the role of the apoptosis-counteracting protein bcl-2, non-Hodgkin lymphomas (NHL, n = 170) were examined immunohistochemically, across the boundaries of histologic classification, for the presence of this oncoprotein, in comparison with apoptotic indices (AI) and percentages of Ki-67+ cells (growth fraction). The results of this retrospective study revealed a highly significant inverse relationship ("mirror image") between the proportion of bcl-2+ cells and the AI per case. Both these parameters, although variable, clearly distinguished low- from high-grade-malignancy lymphomas according to the Kiel classification. Cluster analysis detected 2 separate groups of high-grade NHL, one with rather high AI and low percentages of bcl-2+ cells, comprising most anaplastic large-cell lymphomas, the other group with reverse characteristics. We found no correlation between the percentage of bcl-2+ cells per case and overall survival.

Two different subunits of importin cooperate to recognize nuclear localization signals and bind them to the nuclear envelope

BACKGROUND

Selective protein import into the cell nucleus occurs in two steps: binding to the nuclear envelope, followed by energy-dependent transit through the nuclear pore complex. A 60 kD protein, importin, is essential for the first nuclear import step, and the small G protein Ran/TC4 is essential for the second. We have previously purified the 60kD importin protein (importin 60) as a single polypeptide.

RESULTS

We have identified importin 90, a 90 kD second subunit that dissociates from importin 60 during affinity chromatography on nickel (II)-nitrolotriacetic acid-Sepharose, a technique that was originally used to purify importin 60. Partial amino-acid sequencing of Xenopus importin 90 allowed us to clone and sequence its human homologue; the amino-acid sequence of importin 90 is strikingly conserved between the two species. We have also identified a homologous budding yeast sequence from a database entry. Importin 90 potentiates the effects of importin 60 on nuclear protein import, indicating that the importin complex is the physiological unit responsible for import. To assess whether nuclear localization sequences are recognized by cytosolic receptor proteins, a biotin-tagged conjugate of nuclear localization signals linked to bovine serum albumin was allowed to form complexes with cytosolic proteins in Xenopus egg extracts; the complexes were then retrieved with streptavidin-agarose. The pattern of bound proteins was surprisingly simple and showed only two predominant bands: those of the importin complex. We also expressed the human homologue of importin 60, Rch1p, and found that it was able to replace its Xenopus counterpart in a functional assay. We discuss the relationship of importin 60 and importin 90 to other nuclear import factors.

CONCLUSIONS

Importin consists of a 60 and a 90 kD subunit. Together, they constitute a cytosolic receptor for nuclear localization signals that enables import substrates to bind to the nuclear envelope.

Analysis of early failures after intravesical instillation therapy with bacille Calmette-Guérin for carcinoma in situ of the bladder

OBJECTIVE

To analyse the clinical and therapeutic consequences of early treatment failure after bacille Calmette-Guérin (BCG) instillation therapy for carcinoma in situ of the bladder.

PATIENTS AND METHODS

A total of 115 patients with carcinoma in situ (Tis) of the bladder were treated by intravesical instillation of living BCG vaccine (Immun BCG Pasteur F). Twenty five patients had primary Tis and 90 had secondary Tis with synchronous or prior superficial papillary tumours. All papillary tumours were resected before instillation of BCG. All patients completed one series of 6 weekly instillations of 120 mg BCG.

RESULTS

Twenty-two of 25 patients (88%) with primary Tis responded completely, with negative cytology and cystoscopy findings within a median follow-up period of 44 months. Three of the 25 (12%) had cytological evidence of disease within 9 months of therapy and were considered to be early treatment failures. One patient had muscle-invasive bladder cancer, one had Tis and invasive cancer of the prostatic urethra, and the last, in whom a second BCG course also failed, had Tis of both ureters. Seventy of 90 patients (78%) with secondary Tis had a complete response after treatment with BCG, with repeated negative cytology and cystoscopy examinations within a median follow-up time of 40 months. Twenty of the 90 (22%) with secondary Tis had positive cytology within 9 months after BCG therapy and were considered early treatment failures. Five of these 20 had a cystectomy, three for persistent Tis of the bladder and two for a solid urothelial carcinoma of the prostate. The remaining 15 early failures received a second course of BCG. Four of these 15 patients responded and the remaining 11 failed the second course. The 11 failures included two patients with multifocal T1 G3 bladder cancers. four with invasive bladder cancer, two with solid urothelial carcinomas of the prostatic urethra, and three with Tis of the upper urinary tract.

CONCLUSIONS

According to these data, early treatment failure after 6 weekly instillations of 120 mg Immun BCG Pasteur F is an alarming signal which requires immediate re-assessment of the patient to exclude a muscle-invasive bladder cancer or an extravesical carcinoma in situ, either in the upper urinary tract or in the prostatic urethra.

Adjuvant treatment with a vitamin A analogue (etretinate) after transurethral resection of superficial bladder tumors. Final analysis of a prospective, randomized multicenter trial in Switzerland

Vitamin A and its derivatives, the retinoids, have antiproliferative effects and may induce cellular differentiation. Etretinate, a synthetic retinoid, has a more favorable therapeutic index experimentally than all-trans-retinoic acid or 13-cis-retinoic acid. Ninety patients with superficial papillary bladder tumors stages Ta and T1 entered a prospective randomized double-blind multicenter trial in Switzerland. Seventy-nine of the patients were eligible and received either 25 mg of etretinate or a placebo orally each day. The early withdrawal of a significantly greater number of patients in the placebo group for treatment failure during the first year of the study resulted in a secondary positive selection in this group. High-risk patients were removed and low-risk patients remained. In those patients who had tumor recurrences after randomization, the time to first recurrence was similar in both groups with 13.5 and 13.6 months in the placebo and etretinate groups, respectively. However, the mean interval to subsequent tumor recurrence was significantly longer in the etretinate group. The mean interval between recurrences in these subgroups was 12.7 months in the placebo arm and 20.3 months in the etretinate arm (p = 0.006). Consequently, the number of transurethral resections per patient-year was also reduced significantly in the etretinate group (p < 0.001). In patients with more than one transurethral resection of papillary tumors before randomization, the annual transurethral resection rate in the two treatment groups dropped from 1.7 to 1.3 in the 30 patients in the placebo group (NS, p = 0.1) and from 2.1 to 0.95 in the 25 patients in the etretinate group (p < 0.001). The side effects of etretinate (cheilitis, dryness of mucous membranes and skin) were acceptable to most patients. The relationship of the 3 myocardial infarcts observed in the etretinate group to the retinoid is not clear. Despite their significant effect on the recurrence rate of superficial papillary bladder tumors, retinoids should only be used in well-controlled prospective trials until more is known about their dosage-toxicity profiles.

Spatial distribution of mitosis, apoptosis and small blood vessels in malignant diffuse follicular-center-cell lymphomas: a nearest-neighbor analysis

To better comprehend the relationships between cell birth and cell death in neoplastic disorders, the topography of these events needs to be considered. We applied a computerized nearest-neighbor analysis to malignant, diffuse follicular-center-cell lymphomas in order to examine the spatial distribution of pyknotic (apoptotic) cells/bodies (A) and mitotic figures (M) in relation to capillaries (C) and venules (V). The results revealed a complex dispersion pattern, with significant aggregations of A and M, in addition to an even greater random distribution component. The greatest clustering displayed by A was around capillaries (A-C, 42% reduction of object frequency between the first and second distance class), followed by A-A (33%), A-V (24%) and A-M (12%). Additional values for mitotic figures were: M-M (45%), M-V (33%) and M-C (22%). These findings may reflect the relative importance of inherent properties of the neoplastic and host factors, respectively, in the regulation of cell birth and cell death rates.

C-terminal region of adrenodoxin affects its structural integrity and determines differences in its electron transfer function to cytochrome P-450

The role of the C-terminal region of adrenodoxin was studied by analyzing deletion mutants 4-114 and 4-108 lacking amino acids 1-3 and 115-128 or 109-128, respectively. Absorption spectra of these mutants were found to be identical to that of wild type adrenodoxin. However, EPR and CD studies indicated that the structure of deletion mutants 4-114 and 4-108 differs from that of wild type adrenodoxin. Mutant 4-107, which in addition to residues 109-128 lacks the unique proline 108, showed no EPR spectrum. This indicates that proline 108 plays an essential role for the formation of the iron-sulfur cluster. Deletion of residues 115-128 or 109-128 did not essentially affect adrenodoxin reductase binding as shown by nearly unchanged cytochrome c reduction activity. In a CYP11A1 assay, mutants 4-108 and 4-114 exhibited 3.2- and 5-fold decreased Km values, respectively, whilst the Kd values for CYP11A1 decreased 3- and 1.9-fold, respectively. Additionally, in a CYP11B1 assay, mutants 4-108 and 4-114 showed decreased Km values. Furthermore, the first step of electron transfer to CYP11B1, but not to CYP11A1, was accelerated up to 4.5-fold by the adrenodoxin mutants. The results suggest that the C-terminal peptide of adrenodoxin, especially proline 108, affects the structural integrity of the iron-sulfur cluster and that electron donation from adrenodoxin to CYP11A1 and CYP11B1 is determined at least in part by different features of the cytochromes.

Drosophila mode of metamerization in the embryogenesis of the lepidopteran insect Manduca sexta

Insect embryos have been classified as intermediate- and short-germ embryos, in which posterior segments are thought to be generated sequentially from an uncommitted growth zone, or as long-term embryos, such as Drosophila melanogaster, which develop primordia for all segments simultaneously. In Drosophila the coordinated activities among a three-tiered cascade of zygotic segmentation genes subdivide the embryo into progressively smaller units along the anterior-posterior axis. The mode of pattern specification in lepidopteran embryos has not been determined, although on morphological grounds they have been characterized as intermediate-germ insects. We have cloned orthologues of Drosophila segmentation genes from the tobacco hawkmoth Manduca sexta and have found that the blastoderm expression patterns of these genes show a molecular prepatterning typical of Drosophila. Thus, successive segment formation in Manduca embryos may not be due to sequential addition but rather may be the consequence of a lateral compression of the embryo proceeding in an anterior-to-posterior progression. These data challenge the view that the classification of insect development according to morphological criteria can serve as a reliable indicator of the molecular mechanisms underlying segmentation.

Adjuvant cisplatin chemotherapy following cystectomy for bladder cancer: results of a prospective randomized trial

Between April 1984 and May 1989, 77 eligible patients with invasive, nonmetastatic (stage M0) transitional cell carcinoma of the bladder were stratified after radical cystectomy and pelvic lymph node dissection on the basis of nodal status (stage pN0 versus pN1-2) and were randomly assigned to either observation or postoperative cisplatin chemotherapy (3 courses of 90 mg./m.2 cisplatin given for 3 consecutive days at monthly intervals). Patient eligibility included a creatinine clearance of greater than 60 ml. per minute. There were 40 eligible patients in the control group (median age 61 years) and 37 in the cisplatin group (median age 64 years). In regard to postoperative tumor stage and nodal status, there was no statistical difference between the 2 patient groups. In the cisplatin group 21 patients received the full dose, 9 required dose reduction and 7 refused treatment. Median followup was 5 years 9 months (range 3 to 8 years). Survival analysis showed no significant difference (log rank p = 0.65) between the 40 patients in the control group and the 37 in the cisplatin group. The survival rate at 5 years was 54% (95% confidence interval 39 to 69%) in the control group and 57% (95% confidence interval 40 to 74%) in the treatment group. Patients with cancer confined to the bladder wall (stage pT3a or less) had a 5-year overall survival rate of 70% and those with tumor growth in the perivesical fat or into the prostate (stages pT3b plus pT4a) had a 5-year overall survival rate of 40%. This difference in survival between the low stage subgroup (stages pT3a or less) and the high stage subgroup (pT3b plus pT4a) is highly significant (p = 0.0043). However, no difference between the controls and the cisplatin group was found within either the low or high stage subgroups. The reasons for failing to show a survival benefit from adjuvant high dose cisplatin monotherapy after radical cystectomy are discussed.

Generation of the soluble and functional cytosolic domain of microsomal cytochrome P450 52A3

The cytosolic domain of microsomal P450 52A3 (P450Cm1) was isolated as a soluble and functionally active protein. The NH2-terminal region that anchors the P450 protein to the endoplasmic reticulum was removed by sequence-specific proteolysis at a designed cleavage site. For that purpose, P450Cm1 was genetically engineered to establish at position 63-66 the sequence Ile-Glu-Gly-Arg, which is recognized by the restriction protease factor Xa. The modified P450 was produced in high yields as an integral membrane protein in Saccharomyces cerevisiae. In the microsomal fraction, it was accessible to factor Xa digestion, releasing a readily soluble, shortened P450 protein. For large scale preparation of the cytosolic domain, the modified P450Cm1 was first purified and then subjected to sequence-specific proteolysis. The highly purified delta(1-66)P450Cm1 exhibited unchanged spectral characteristics and catalyzed the hydroxylation of n-hexadecane with 85% of the activity determined for full-length wild-type P450Cm1. The method developed for the preparation of the cytosolic domain of P450Cm1 may be more generally applicable to facilitate structure-function studies on membrane-bound P450 forms.

Invasion depth is the most important prognostic factor for transitional-cell carcinoma in a prospective trial of radical cystectomy and adjuvant chemotherapy

The aim of this prospective study was to examine the prognostic pathomorphological factors in urothelial cancer of the urinary bladder. Clinical and morphological variables were evaluated by univariate and multivariate analysis in 70 patients with invasive transitional-cell carcinoma of the bladder (pTI-pT4a). The patients were treated according to a prospective program consisting of radical cystectomy and pelvic-node dissection, either alone or followed by adjuvant cisplatinum chemotherapy. Nodal status was pN0 in 89% of the patients. The median follow-up time was 5.75 years and the 5-year survival was 58%. Among the morphologic variables, deep invasion of the bladder wall and squamous differentiation indicated a poorer prognosis. Differentiation grade, pattern of growth (infiltrating versus expanding), angioinvasive growth, glandular differentiation and concomitant prostate carcinoma (pT1) were not significative factors for survival. By contrast, a significant reduction in mortality rate was found in patients with concomitant carcinoma in situ. Multivariate analysis confirmed that depth of invasion is an independent prognostic factor of outcome. The results confirm the primary importance of tumor stage in the prediction of survival after radical cystectomy.

[Morphological diagnosis and classification of lung tumors]

Morphologic examination is mandatory for distinction between benign and malignant pulmonary lesions and separation of primary tumors from metastatic disease. Tumors are classified as to their type and grade by histology and/or cytology. Differences in behavior and response to treatment make the distinction between small cell carcinoma [SCLC] and non-small cell carcinoma [NSCLS] the single most important decision the pathologist must make when examining a lung tumor. The considerable cellular heterogeneity of bronchogenic carcinoma may be the source of problems and pitfalls in morphologic classification of these tumors, discussed in this review together with the concept of neuroendocrine neoplasms.