alpha-Fetoprotein-producing (hepatoid) carcinoma of the fallopian tube

This report describes a case of alpha-fetoprotein (AFP)-producing carcinoma of the fallopian tube. The patient was a 52-year-old woman who presented with an abnormally high serum level of AFP. A left adnexal mass was discovered in the subsequent close examination. Hysterectomy and adnexectomy revealed a 3 x 3 x 4-cm tumor in the fimbriae of the left tube. Histologically and immunohistochemically, the tumor was diagnosed as an AFP-producing (hepatoid) carcinoma arising in the fallopian tube. To our knowledge, this is the first report of such a tumor appearing in the tube. This case supports the view that hepatoid cells may also arise from the müllerian epithelium.

Crystallization and preliminary X-ray analysis of a histidine kinase domain of the anaerobic sensor protein ArcB from Escherichia coli

Crystals of a novel histidine protein kinase domain of the anaerobic sensor protein ArcB from Escherichia coli have been obtained by a hanging-drop vapor-diffusion method with micro- and macroseeding techniques. Preliminary X-ray crystallographic analysis revealed that they belong to space group P2(1)2(1)2(1) with dimensions a = 30.56, b = 34.93 and c = 110.78 A, having one molecule in the crystallographic asymmetric unit. The crystals diffract to at least 2.0 A resolution.

Identification of the nuclear localization signal of mouse DNA primase: nuclear transport of p46 subunit is facilitated by interaction with p54 subunit

DNA polymerase alpha-primase is a replication enzyme necessary for DNA replication in all eukaryotes. Mouse DNA primase is composed of two subunits: a 46 kDa protein (p46), which is the catalytic subunit capable of RNA primer synthesis, and a 54 kDa protein (p54), whose physiological role is not clear. To understand the structure-function relationship of DNA primase, we set out to characterize these two subunits individually or in combination using a cDNA expression system in mammalian cultured cells, and determined the subcellular distribution of ectopically expressed DNA primase. The p54 expressed in COS-1 cells after transfection was predominantly localized in the nucleus, whereas p46 was retained in the cytoplasm as shown by indirect immunofluorescence analysis. Using several mutant proteins with deletions or substitutions as well as chimeric constructs, we identified the nuclear localization signal of p54 as RIRKKLR, encoded near the amino terminus (residues 6–12). Furthermore, co-expression of both p46 and p54 subunits markedly altered the subcellular distribution of p46; co-expressed p46 was transported into the nucleus as efficiently as p54. These results demonstrate that p54 has a nuclear localization signal and is able to be translocated into the nucleus independently of DNA polymerase alpha subunits. In contrast, p46 lacks a nuclear localization signal, and its nuclear translocation is facilitated by interaction with p54. We present here first evidence for a novel role of p54 in the nuclear translocation process, and a piggy-back binding transport mechanism of mouse DNA primase.

[Cavitary lung cancer with a fungus ball-like shadow]

A 75-year-old woman had an irregularly shaped cavitary lesion in the right upper lung field on a chest X-ray film and a CT scan. Primary lung cancer was suspected, but no evidence of malignancy or of infection was found on examination of specimens obtained by transbronchial biopsy and by lavage. Seven months after the first examination the cavity was found to have enlarged and an intra-cavitary fungus ball like shadow was seen. On the basis of these findings, pulmonary aspergilloma with or without primary lung cancer was suspected. Examination of a specimen obtained by transbronchial biopsy revealed squamous cell carcinoma. Right upper lobectomy was done, and the resected tissue included a polypoid nodule and a cavity wall composed of a milky-white solid tumor. Microscopic examination revealed a moderately differentiated squamous cell carcinoma in both the cavity wall and the polypoid nodule, and no evidence of fungal involvement.

Systematic mutational analysis revealing the functional domain organization of Escherichia coli nucleoid protein H-NS

The Escherichia coli H-NS protein is one of the major constituents of the nucleoid structure. This protein has been implicated not only in the compact organization of the nucleoid structure, but also in the global regulation of gene expression. H-NS negatively regulates the transcription of a number of apparently unlinked genes on the chromosome, suggesting that it functions as a global transcriptional repressor. In this study, on systematic mutational analysis of hns, three distinct functional domains were found in H-NS, which appear to be responsible for DNA-binding, transcriptional repression and protein-protein interaction (dimerization and/or oligomerization), respectively. We first isolated a number of hns mutations which resulted in derepression of the proVWX operon. These included 20 independent missence mutations each resulting in a single amino acid substitution, and six nonsense mutations each giving a C-terminally truncated form of H-NS. The substituted amino acids were revealed to be located non-randomly in the primary sequence of H-NS. This set of hns mutants was examined extensively in terms of phenotypes and biochemical properties. Based on the in vivo and in vitro results, together with the locations of the altered amino acids, three distinct functional domains were identified in H-NS. Mutations in the C-terminal domain resulted in a loss of its DNA-binding ability, suggesting that this domain is directly involved in its binding to DNA. The N-terminal domain was suggested to be involved in the ability to repress transcription. Mutations in this region abolished its ability to repress the transcription of proV, in vivo and in vitro, without loss of its DNA-binding activity. None of the mutants examined was impaired in the formation of a dimer and/or oligomers, suggesting that the central region of H-NS is involved in oligomerization. These results are discussed with special reference to the molecular mechanism underlying the function of H-NS as a transcriptional repressor. In addition, expression of the bgl operon was found to be affected by only a subset of hns mutations in a highly allele-specific manner. This finding is also addressed with regard to a unique regulatory mechanism (i.e. silencing) for the bgl operon, which is partly mediated by H-NS.

Cyclic GMP elevation by 5-hydroxytryptamine is due to nitric oxide derived from endogenous nitrosothiol in NG108-15 cells

To clarify the involvement of nitric oxide (NO) derived from nitrosothiols (RSNO) in 5-hydroxytryptamine (5-HT)-induced Ca(2+)-independent cGMP formation (CIGF) in NG108-15 cells, we investigated the effects of 5-HT on intracellular contents of RSNO as well as of NO metabolites. 5-HT stimulation resulted in an increase in the intracellular contents of nitrate and cGMP. RSNO was detected in NG108-15 cells and was decreased by 5-HT stimulation. Furthermore, the time course of nitrate increase was coincident with that of RSNO decrease. CarboxyPTIO inhibited 5-HT-induced CIGF, whereas oxyhemoglobin failed to inhibit it. The data suggest that NO is stored in a stable form as RSNO and that 5-HT stimulates NO generation from endogenous RSNO, which is followed by elevation of cGMP via activation of cytosolic guanylyl cyclase by NO in NG108-15 cells. We suggest the existence of a novel 5-HT signal transduction pathway involved in NO generation in NG108-15 cells.

Molecular characterization of feline immunodeficiency virus genome obtained directly from organs of a naturally infected cat with marked neurological symptoms and encephalitis

Feline immunodeficiency virus (FIV) was first isolated from cats with immunodeficiency syndrome. Recently, neurological abnormalities and brain lesions were shown in cats infected with FIV. To investigate the FIV genome associated with central nervous system (CNS) lesions, proviral DNA sequences from the V3-V6 region of the FIV env gene were directly amplified from uncultured necropsy tissues of a 2-year-old naturally FIV-infected cat with marked neurological symptoms and encephalitis. By in situ hybridization, FIV RNA was detected mainly in the astrocytes. Fifteen clones isolated from cerebrum, bone marrow and lymph node samples showed only a small number of mutations or deletions in this region. A representative clone, JN-BR1, was distantly related to the previous Japanese strain (TM2) belonging to the subtype B. However, it was relatively close to the Petaluma strain which is known to infect feline brain-derived culture cells and induce brain lesions in inoculated cats. By phylogenetic analysis, the JN-BR1 strain was placed in subtype A that included Petaluma strain and several other American and European strains. The JN-BR1 strain derived from brain with encephalitis in this study and the Petaluma strain may share a common genetic structure that is related to their neuropathogenicity.

[Mitral reconstruction in patients with infective endocarditis]

Between June 1992 and October 1993, 5 patients with infective endocarditis in native mitral valve underwent open heart surgery. The patients ranged in age from 51 to 64 years and were all males. According to NYHA functional classification, 4 patients were class II and one was class III. Surgery was indicated because of hemodynamic deterioration (2 pts), echocardiographic mobile vegetation with or without previous emboli (2 pts) and both condition (1 pt). Before surgery the patients were afebrile and had negative serum CRP and negative blood cultures for at least one week after adequate medical treatment. The leaflet lesions found in the 5 patients were vegetation (2 pts), perforation (1 pt), calcification (1 pt) and thickening (2 pts). The chordal lesions found were rupture (5 pts) and thickening (1 pt). The infective lesions did not extend to the annulus. The mitral leaflets, including all apparently infectious lesions, were resected in a V-shaped fashion and then valve reconstruction was performed. The resected parts were sutured together with anchoring chordae. The annuloplasty with Teflon-tapes was also added. Postoperatively, all 5 patients showed a dramatic improvement in hemodynamics and endocarditis did not recur during 22 to 38 months of follow-up. The patients who received the repair did not require Warfarin. This study shows that mitral valve repair is an acceptable operation in patients with infective endocarditis, giving the patients better quality of life than mitral valve replacement when (1) infectious lesion are limited to mitral leaflet and chordae, (2) there is no severe calcification of the mitral valve, (3) the infection is healed by the adequate antibiotic therapy.

A novel gene that interferes with the phosphotransfer signal transduction mediated by the EnvZ osmosensor in Escherichia coli

In Escherichia coli, expression of the major outer membrane proteins, OmpC and OmpF, is regulated in response to the medium osmolarity and other environmental stimuli. A two-component signal transduction system, mediated by EnvZ and OmpR, is crucially responsible for this osmotic regulation of the ompC and ompF genes. In this study, an E. coli gene was cloned, which interferes with expression of both the ompC and ompF genes at the level of transcription, provided that the cloned gene was introduced in E. coli cells by a multicopy plasmid. The gene product was identified as F107, which was previously characterized as a hypothetical protein in E. coli genome databases. F107 containing 107 amino acids appears to be highly hydrophobic, and has a sequence similarity to the eukaryotic type of cytochrome-c oxidase subunit III. The mechanism by which F107 inhibits transcription of ompC and ompF was examined extensively, mainly by using a set of envZ and ompR mutants. These results suggested that F107 interferes specifically with a function of the EnvZ osmosensory kinase. Possible mechanisms by which F107 affects the EnvZ function are discussed.

Detection of apoptosis induced in peripheral blood lymphocytes from cats infected with feline immunodeficiency virus

Peripheral blood lymphocytes (PBL) from cats infected with feline immunodeficiency virus (FIV) were examined for the occurrence of apoptosis after short-term culture. In the PBL from FIV-infected cats, changes in flow-cytometry scattergram, morphological characteristics of apoptosis and nucleosomal DNA fragmentation were observed. Percentages of apoptotic cells by flowcytometry analysis in PBL from FIV-infected cats (22.4% +/- 9.4%) were significantly higher than those in PBL from uninfected control cats (9.2% +/- 3.5%). The lymphocytes which underwent apoptosis included CD5+, CD4+ and sIgM+ cells, indicating that induction of apoptosis was not restricted to a special subset of lymphocytes. These findings provide evidence of the apoptotic state of PBL in cats with FIV infection.

Gain-of-function p53 mutations enhance alteration of the T-cell receptor following X-irradiation, independently of the cell cycle and cell survival

Missense mutations are by the far the most common types of mutations found in p53 of human tumors, suggesting that mutant p53 proteins function either by abrogating wild-type function or by gaining new oncogenic functions. To distinguish between the dominant-negative effect and gain of new function of p53 missense mutants, we measured the ability of transfected missense mutant p53s in p53-null Jurkat cells to alter T-cell receptor (TCR) surface expression. The TCR is a key signal transduction moiety common to T lymphocytes and is one of the major sites for aberrations in T-cell leukemias/lymphomas. Three p53 mutants (248trp, 249ser, and 273his) enhanced the frequency of TCR mutants after graded doses of X-radiation compared to null p53 parent- and wild-type p53-possessing normal lymphocytes; the parent Jurkat and normal lymphocyte showed no difference. These enhancements were not the results of a change in radiosensitivity or in G1 checkpoint arrest characteristics. Therefore, the creation of this mutator phenotype by missense-type p53 mutations implies that a more direct mechanism, apart from changes of cell cycle kinetics or cell death, may be responsible for the selection of certain p53 point mutations, which eventually result in the tumorigenesis of the cell.

[Abnormal branching of left pulmonary artery to the lateral and posterior basal segments]

A 70-year-old male, underwent left lower lobectomy due to lung cancer, had an extremely rare form of left pulmonary artery branching. His pulmonary artery supplying to lateral and posterior basal segments (A9 + 10) was arisen anteriorly from the root of the left pulmonary artery in the mediastinum and ran below in the anterior portion of the upper lobe stem bronchus. Embriologically, this abnormality might be due to a derangement of anastomosis between the pulmonary arch system and splanic plexus in primitive lung, and was interpreted as one of the pulmonary sequestration. Clinically, particularly at thoracotomy, the presence of a large vessel in an unexpected location is very hazardous, so that preoperative pulmonary angiography is useful to detect the abnormal branching.

SomA, a novel gene that encodes a major outer-membrane protein of Synechococcus sp. PCC 7942

The outer membrane of a cyanobacterium (Synechococcus sp. strain PCC 7942) contains only a few major proteins. A gene encoding one of them, somA, was cloned and characterized. Based on the nucleotide sequence, SomA was predicted to comprise 531 amino acids with a calculated molecular mass of 57,136 Da. The deduced amino acid sequence of SomA shares similarities with two bacterial cell-surface proteins, the S-layer protein of Thermus thermophilus and the flagellin of Campylobacter coli. The predicted amino acid sequence of SomA revealed also that it contains a signal peptide-like sequence at its N terminus. This signal peptide-like sequence was capable of mediating protein translocation across the cytoplasmic membrane into the outer membrane of Escherichia coli, provided that this sequence was fused to the E. coli outer-membrane protein, OmpF. The signal peptide-like sequence was cleaved upon the translocation of the SomA::OmpF protein. We suggest that SomA is synthesized as a precursor and that its N-terminal 24 amino acid sequence is a cleavable signal peptide involved in protein targeting into the outer membrane. To our knowledge, this is the first example of cleavable signal peptides for proteins transported into the outer membrane of cyanobacteria.

Crystallins from rat lens are especially susceptible to calpain-induced light scattering compared to other species

PURPOSE

To compare the susceptibility of crystallins from various animal species to formation of light scattering elements after proteolysis by calpain II enzyme (EC 3.4.22.17).

METHODS

Lens, total soluble proteins from: 12-day and 4-week old rat, fetal and adult bovine, 16-day embryonic and 10-week chicken, and young human cortex and nucleus were proteolyzed by either endogenous lens calpain or addition of purified calpain II for 24 h followed by incubation for up to 11 days. Absorbance of light at 405 nm estimated light scattering by crystallins; SDS-PAGE and 2D-electrophoresis assessed proteolysis on the crystallins.

RESULTS

Most rapid light scattering occurred with total soluble proteins from young rat lens, either after adding purified calpain or by activating endogenous lens calpain with calcium. (Only rat lens showed activation of endogenous calpain II.) beta-crystallin polypeptides from rat, bovine, human, and to a more limited extent, chick lens were partially proteolyzed by addition of purified calpain II. In spite of this proteolysis, total soluble proteins from chicken, bovine, and human lenses showed no obvious light scattering by action of calpain. Crystallins from older rat lens showed approximately 50% of the light scattering displayed by crystallins from younger rats after 3 days, but only when purified calpain was added.

CONCLUSIONS

Our results indicate an unusually high susceptibility of crystallin polypeptides from young rat lens to formation of light scattering elements after limited proteolysis. Thus, young rat lens provides a unique opportunity to investigate how properties of crystallins influence the development of light scattering found in cataract.

Feasibility of using decades-old archival tissues in molecular oncology/epidemiology

Archival tissues are a bountiful resource for various studies. Polymerase chain reaction permits the use of such tissues for molecular biological analyses of disease causation. However, a comprehensive study using a large number of decades-old samples (20 or more years) for molecular oncology/epidemiology has never been shown to be feasible. We have relied upon the unique tumor registry of atomic bomb survivors to show that such studies are possible using 275 hepatocellular carcinoma and 41 skin cancer cases. We used 23 relatively recent thyroid papillary carcinoma cases from persons living in the vicinity of the Chernobyl nuclear reactor accident for comparison. Degradation of DNA is severe in autopsy hepatocellular carcinoma samples but can be compensated for by decreasing the polymerase chain reaction product size. Increasing the amount of DNA that is used by a factor of 8 improved amplification efficiency from approximately 60 to 80%. Age of the samples was not as great a problem as was the source of procurement. The extracted DNA can be used for all types of assays that require polymerase chain reaction amplification, such as restriction fragment length polymorphism, single-strand conformation polymorphism, and direct sequencing.

Effects of H-NS and potassium glutamate on sigmaS- and sigma70-directed transcription in vitro from osmotically regulated P1 and P2 promoters of proU in Escherichia coli

We have used supercoiled DNA templates in this study to demonstrate that transcription in vitro from the P1 and P2 promoters of the osmoresponsive proU operon of Escherichia coli is preferentially mediated by the sigma(s) and sigma70-bearing RNA polymerase holoenzymes, respectively. Addition of potassium glutamate resulted in the activation of transcription from both P1 and P2 and also led to a pronounced enhancement of sigma(s) selectivity at the P1 promoter. Transcription from P2, and to a lesser extent from P1, was inhibited by the nucleoid protein H-NS but only in the absence of potassium glutamate. This study validates the existence of dual promoters with dual specificities for proU transcription. Our results also support the proposals that potassium, which is known to accumulate in cells grown at high osmolarity, is at least partially responsible for effecting the in vivo induction of proU transcription and that it does so through two mechanisms, directly by the activation of RNA polymerase and indirectly by the relief of repression imposed by H-NS.

H-NS regulates OmpF expression through micF antisense RNA in Escherichia coli

H-NS is a major constituent of the Escherichia coli nucleoid. Expression of the major outer membrane proteins, OmpC and OmpF, is influenced by hns mutations such that OmpC expression increases whereas OmpF expression decreases irrespective of the osmolarity of the medium (K. A. Graeme-Cook, G. May, E. Bremer, and C. F. Higgins, Mol. Microbiol. 3:1287-1294, 1989). In this study we show that the effect of an hns::neo mutation on OmpF expression is largely diminished in a deletion mutant carrying the micF gene that encodes the ompF mRNA-specific antisense RNA. In addition, the micF transcript levels in the hns::neo mutation are high compared with transcript levels in wild-type cells. On the basis of these results, we provide evidence for a link between OmpC/OmpF expression and the regulatory function of H-NS. We suggest that H-NS most likely affects OmpC expression directly at the level of transcription, but OmpF expression is indirectly regulated by micF antisense RNA.

Suppressor mutations in alpha-subunit of RNA polymerase for a mutant of the positive regulator, OmpR, in Escherichia coli

The OmpR protein is a positive regulator specific for the Escherichia coli ompF and ompC genes. This protein functions in a phosphorylation-dependent manner through a presumed interaction with RNA polymerase. We previously isolated OmpR mutants which were suggested to be defective in transcription activation, but not in DNA binding (the so-called positive control (PC) mutant). In this study we isolated mutants of the alpha-subunit of RNA polymerase which can suppress one of the putative PC mutants of OmpR. A crucial amino acid substitution was identified as [V264G] in the alpha-subunit, which is located in the helix H1 of the C-terminal domain, which has been claimed, based on mutational and structural analyses, to be involved in the interaction with other positive regulators including the well-characterized cAMP receptor protein.

[Extraperitoneal laparoscopic adrenalectomy: the initial 9 cases]

(PURPOSE). To determine the efficacy of extraperitoneal laparoscopic adrenalectomy for patients with adrenal tumor, the clinical results of 9 patients treated with this procedure were analysed. (PATIENT AND METHOD). Between July 1994 and March 1995, we have performed extraperitoneal laparoscopic adrenalectomy using the modified Gaur technique of balloon dilatation of the retroperitoneum in 4 men and 5 women with unilaterla small adrenal tumor who were 30 to 79 years old (mean age 56 years). Preoperative diagnosis was primary aldosteronism in 2, 18-hydroxycorticosterone producing adnoma in 1, pre-Cushing syndrome in 5, and nonfunctioning adrenal tumor in 1 patient. The operations were performed with the patients on lateral position and 4 torocars were positioned. The retroperitoneal space was first dissected bluntly by the index finger and a balloon dissector through a small skin incision, and the retroperitoneal space was insufflated with carbon dioxide at the pressure of 10 to 12 mmHg. After the dissection of the adrenal gland, adrenal vein was clipped and transected. The completely freed adrenal gland was enclosed in an entrapment sack and removed en bloc through the open laparoscopy wound. (RESULTS). All 9 procedures were successfully performed. The mean estimated blood loss and the mean operating time were 53 ml and 168 min respectively. There was no intraoperative complication. A postoperative retroperitoneal hematoma was observed in one patient, however it spontaneously resolved without surgical management. (CONCLUSION). In open adrenalectomy, the benefit of the extraperitoneal approach (excluding patients with pheochromocytoma or bilateral lesions) have already been established elsewhere. Although the working space is smaller than that of peritoneal approach, and the surgical techniques are slightly more difficult, extraperitoneal laparoscopic adrenalectomy promises to be safe and a minimally invasive treatment for patients with unilateral small adrenal tumors except for pheochromocytoma.

Age-related changes in diurnal acetylcholine release in the prefrontal cortex of male rats as measured by microdialysis

Extracellular levels of acetylcholine in the prefrontal cortex were measured using the micro-dialysis method in freely moving young (three to four months old) and old (23 to 24 months old) male rats over a period of 24 h to examine the effect of aging on prefrontal acetylcholine release. Prefrontal acetylcholine release during a 24 h period exhibited a diurnal variation with higher levels during the dark cycle than during the light cycle in young rats but not in old rats. In addition, prefrontal acetylcholine release was closely associated with spontaneous activity in young rats but not in old rats. The present study suggests that aging reduces diurnal changes in the prefrontal acetylcholine release and that there is a cross-correlation between the prefrontal acetylcholine release and spontaneous locomotor activity in male rats.