Posterior Reversible Encephalopathy Syndrome after a Variety of Combined Chemotherapies Containing Bevacizumab for Metastatic Colon Cancer

A 44-year-old woman with advanced metastatic colon cancer received chemotherapies comprising oxaliplatin and capecitabine (XELOX), irinotecan hydrochloride, leucovorin calcium and fluorouracil irinotecan (FOLFIRI)/panitumumab and mFOLFOX6/bevacizumab. Fifteen months later, she presented with the acute onset of a headache, drowsiness and seizure with a fever and hypertension. Brain magnetic resonance imaging (MRI) indicated bilateral regions of signal hyperintensity in the white matter with spasms of bilateral cerebral arteries apparent on magnetic resonance angiography. Posterior reversible encephalopathy syndrome (PRES) was diagnosed, and treatments resulted in improvement of the MRI findings, but the patient experienced cerebral infarction and ultimately died of deterioration of cancer on day 26 after the onset of PRES.

Suppression of astrocyte lineage in adult hippocampal progenitor cells expressing hippocampal cholinergic neurostimulating Peptide precursor in an in vivo ischemic model

Hippocampal cholinergic neurostimulating peptide (HCNP) is known to promote differentiation of septohippocampal cholinergic neurons. The HCNP precursor protein (HCNP-pp) may play several roles, for example, as an ATP-binding protein, a Raf kinase inhibitor protein, and a phosphatidylethanolamine-binding protein, as well as a precursor for HCNP. This study therefore aimed to elucidate the involvement of HCNP-pp in specific neural lineages after stroke using a hypoxic-ischemic (HI) rat model of brain ischemia. The specific neural lineages in the hippocampus were investigated 14 days after ischemia. Some bromodeoxyuridine (BrdU)(+) neural progenitor cells in the hippocampus of hypoxic, HI, or sham-operated rats expressed HCNP-pp. Almost half of the BrdU(+)/HCNP-pp(+) cells also expressed the oligodendrocyte lineage marker 2',3'-cyclic nucleotide 3'-phosphodiesterase, whereas only a few BrdU(+)/HCNP-pp(+) cells in the hippocampus in HI brains expressed the neuronal lineage marker, doublecortin (DCX). Interestingly, no BrdU(+)/HCNP-pp(+) progenitor cells in hypoxic, HI, or sham-operated brains expressed the astrocyte lineage marker, glial fibrillary acidic protein. Together with previous in vitro data, the results of this study suggest that the expression level of HCNP-pp regulates the differentiation of neural progenitor cells into specific neural lineages in the HI hippocampus, indicating that neural stem cell fate can be controlled via the HCNP-pp mediating pathway.

Suppressed phosphorylation of collapsin response mediator protein-2 in the hippocampus of HCNP precursor transgenic mice

We previously reported a novel peptide, Hippocampal Cholinergic Neurostimulating Peptide (HCNP), which induces acetylcholine synthesis by increasing the amount of choline acetyltransferase (ChAT) in medial septal nuclei. The HCNP precursor protein (HCNP-pp), composed of 186 amino acids, is an inhibitory factor of the c-Raf/MEK cascade and may be involved in fetal rat brain development via the inhibition of phosphorylation of Erk. To clarify the involvement of HCNP in hippocampal cholinergic circuitry, we previously generated HCNP-pp transgenic (HCNP-pp Tg) mice using the promoter of the α subunit of Ca(2+) calmodulin-dependent protein kinase II (CaMKIIα). These mice showed increased levels of ChAT in medial septal nuclei at 12 weeks of age, and the phenotype of depressive mood at 30 weeks of age. Here, through proteomic analysis we investigated the alteration of protein expression in the hippocampus of HCNP-pp Tg mice compared with wild-type littermate mice. We demonstrate that the activation of collapsin response mediator protein-2 (CRMP-2) is increased in the transgenic mice at 12 weeks of age when compared with wild-type littermate mice.

Overexpression of hippocampal cholinergic neurostimulating peptide in heterozygous transgenic mice increases the amount of ChAT in the medial septal nucleus

Acetylcholine modulates neural activity in the hippocampal glutamatergic pathway via the induction of phosphorylated Erk and may act as a novel transmitter in septohippocampal memory formation. However, how acetylcholine synthesis in the septal nucleus is regulated is unknown. We have purified a peptide from the hippocampus of the young adult rat, named hippocampal cholinergic neurostimulating peptide (HCNP) that induces acetylcholine synthesis in vitro in the septal nucleus. Previously, levels of this peptide and/or precursor protein were reported to be decreased, and the protein to be nitrated in the brains of patients with Alzheimer's disease. Here, to clarify the involvement in the regulation of acetylcholine synthesis in vivo in the medial septal nucleus, we generated HCNP precursor transgenic mice, using a Ca2+ calmodulin-dependent protein kinase II genomic promoter. The amount of cholineacetyltransferase (ChAT) in the medial septal nucleus was increased in heterozygous HCNP transgenic mice, compared with non-transgenic littermates. This result suggests that HCNP is involved in regulating acetylcholine synthesis in vivo in the medial septal nucleus and, as such, is important for memory function.

[A case of neurolymphomatosis diagnosed with FDG-PET]

A 38-year-old man with non-Hodgkin's lymphoma presented with hypesthesia and muscle weakness in the left upper limb. A lack of F-waves in left median and ulnar nerve conduction studies suggested a lesion at the proximal segments of the peripheral nerves, such as the left brachial plexus or nerve roots. Cervical magnetic resonance imaging revealed no lesions compressing nerve roots or peripheral nerves. Small and obscure uptake on the left side of the cervical nerve roots on 67Ga-scintigraphy was indistinguishable from artifact. Positron emission tomography-computed tomography (PET/CT) revealed a region of high glucose uptake in a left cervical intervertebral foramen, leading to a diagnosis of neurolymphomatosis. Neurological symptoms improved following additional chemotherapy, and the high glucose-uptake lesion disappeared. FDG-PET/CT is useful for rapid and non-invasive evaluation of neurolymphomatosis.

[An adult case of cyclic vomiting syndrome in which tricyclic antidepressant was effective]

A 30-year-old man presented with a 10-year history of recurrent, stereotypic episodes of incapacitating nausea and vomiting. Initially, he had been diagnosed as having superior mesenteric artery syndrome, and had undergone abdominal surgery at age 20. The patient was in good health between episodes. During each episode, oral intake was impossible and total parenteral nutrition and sedation were necessary. Conventional antiemetics such as metoclopramide were not effective, and the 5-HT3 antagonist ondansetron hydrochloride was only partially effective. Investigations into gastrointestinal, hormonal, and metabolic function were unremarkable, as was psychiatric evaluation. Diagnosing this to be an adult case of cyclic vomiting syndrome, we administered amitriptyline hydrochloride; a prophylactic agent for migraine. This resulted in rapid resolution of the episodes, which have not recurred over several years' follow up. Recently, cyclic vomiting syndrome has been considered a subtype of migraine. In the present case, effectiveness of the tricyclic antidepressant amitriptyline hydrochloride indicated that migraine and cyclic vomiting syndrome have a common pathology. Clinicians should be aware that cyclic vomiting syndrome can affect adults as well as children, and that treatment for migraine may be effective.

[An autopsy case of purulent meningitis, presenting high signals in subarachnoid space and ventricles in diffusion weighted images (DWIs)]

A 79-year-old, bedridden woman with an untreated colon cancer, developed abrupt disturbance of consciousness and high fever. Brain MRI showed significant high signals in the subarachnoid space and ventricles in diffusion-weighted images (DWIs), and she died on the same day. At autopsy, much exudate was found over the base of the brain, leading to a diagnosis of purulent meningitis. On histological findings, inflammatory cell infiltration was significantly restricted within the subarachnoid space, but not into the brain parenchyma. This case report demonstrated that high signals in subarachnoid space and ventricles in DWIs may be very useful for diagnosis of purulent meningitis.

Heterodimer formation between the antimicrobial peptides magainin 2 and PGLa in lipid bilayers: a cross-linking study

The antimicrobial peptides magainin 2 and PGLa, isolated from the skin of the African clawed frog Xenopus laevis, show marked synergism [Westerhoff, H. V., Zasloff, M., Rosner, J. L., Hendler, R. W., de Waal, A., Vaz Gomes, A., Jongsma, A. P. M., Riethorst, A., and Juretic, D. (1995) Eur. J. Biochem. 228, 257-264]. We suggested previously that these peptides form a potent heterodimer composed of either parallel or antiparallel helices in membranes [Matsuzaki, K., Mitani, Y., Akada, K., Murase, O., Yoneyama, S., Zasloff, M., and Miyajima, K. (1998) Biochemistry 37, 15144-15153]. To detect the putative heterodimer by chemical cross-linking, analogues of magainin 2 and PGLa with a Cys residue at either terminus were synthesized. These cross-linking experiments suggested that both peptides form a parallel heterodimer in membranes composed of phosphatidylglycerol/phosphatidylcholine but not in either buffer or a helix-promoting 2,2,2-trifluoroethanol/buffer mixture. The isolated parallel heterodimers exhibited an order of magnitude higher membrane permeabilization activity compared with the monomeric species, indicating that the observed synergism is due to heterodimer formation.

Genetic and functional analysis of PARP, a DNA strand break-binding enzyme

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme activated by binding to a single- or double-strand break of DNA and is one of the death substrates for caspase-3 in apoptosis. The nuclear function of PARP is well studied and recent PARP-knockout studies indicate that PARP takes part in chromosomal stability. To analyze the effect of PARP overexpression, or loss of function, we have cloned PARP cDNA and the gene from Drosophila melanogaster and studied its function in developmental stages. Organization of exons corresponds to the functional domains of PARP. An alternatively spliced form of PARP lacking exon 5, which encodes the auto-modification domain, is found in Drosophila. Expression of the PARP gene is at high levels in embryos at 0-6h after egg laying and gradually decreased. In situ mRNA hybridization indicates localization of PARP mRNA in cells along the central nervous system at a late stage of embryogenesis. Overexpression of the gene in the developing eye primordia of D. melanogaster is an excellent experimental model to analyze the cell cycle and programmed cell death. We introduced PARP expression vector overexpresses PARP in the eye discs of Drosophila, and established the PARP transgenic flies by P element-mediated germ line transformation. These flies showed mild roughening of the normally smooth ommatidial lattice involving tissue polarity disruption characterized by missrotation and incorrect chirality of ommatidia. Possible mechanisms of involvement of PARP in the development are discussed.

Mutagenic and nonmutagenic bypass of DNA lesions by Drosophila DNA polymerases dpoleta and dpoliota

cDNA sequences were identified and isolated that encode Drosophila homologues of human Rad30A and Rad30B called drad30A and drad30B. Here we show that the C-terminal-truncated forms of the drad30A and drad30B gene products, designated dpoletaDeltaC and dpoliotaDeltaC, respectively, exhibit DNA polymerase activity. dpoletaDeltaC and dpoliotaDeltaC efficiently bypass a cis-syn-cyclobutane thymine-thymine (TT) dimer in a mostly error-free manner. dpoletaDeltaC shows limited ability to bypass a 6-4-photoproduct ((6-4)PP) at thymine-thymine (TT-(6-4)PP) or at thymine-cytosine (TC-(6-4)PP) in an error-prone manner. dpoliotaDeltaC scarcely bypasses these lesions. Thus, the fidelity of translesion synthesis depends on the identity of the lesion and on the polymerase. The human XPV gene product, hpoleta, bypasses cis-syn-cyclobutane thymine-thymine dimer efficiently in a mostly error-free manner but does not bypass TT-(6-4)PP, whereas Escherichia coli DNA polymerase V (UmuD'(2)C complex) bypasses both lesions, especially TT-(6-4)PP, in an error-prone manner (Tang, M., Pham, P., Shen, X., Taylor, J. S., O'Donnell, M., Woodgate, R., and Goodman, M. F. (2000) Nature 404, 1014-1018). Both dpoletaDeltaC and DNA polymerase V preferentially incorporate GA opposite TT-(6-4)PP. The chemical structure of the lesions and the similarity in the nucleotides incorporated suggest that structural information in the altered bases contribute to nucleotide selection during incorporation opposite these lesions by these polymerases.

Transient osteoporosis of the hip during pregnancy

We report the clinical features of and MRI findings in transient osteoporosis of the hip during pregnancy. The study population consisted of 4 patients with a mean age of 33 years. The mean gestational age at onset was 31 weeks (range: 27 to 35 weeks). The main symptoms consisted of a weight-bearing pain in the hip and gait disturbance. The pain occurred suddenly and was of unknown cause and became severe within 2 to 3 weeks. X-ray examinations showed diffuse osteoporosis in the femoral head and neck. Moreover in 3 patients, similar lesions were also found in the lumbar spine or the knee. MRI obtained from 3 patients revealed a mottled low-signal lesion extending from the femoral head and neck on T1-weighted images and a high-signal lesion in the bone marrow suggesting edema on T2-weighted images. Mild elevation of C- reactive protein was shown in 2 patients. Conservative treatments with the limitation of weight bearing and bed rest were performed for all patients, and nonsteroidal anti-inflammatory drugs were given to 3 patients. The hip pain began to decline from 8 to 14 weeks after the onset, and completely disappeared from 14 to 24 weeks. X-ray examinations showed that osteoporotic lesions tended to improve at 10 to 14 weeks, on MRI, a high-signal lesion suggesting bone marrow edema resolved together with relief of the pain. No recurrence was found in any patients at mean follow-up of 70.8 months.

Poly(ADP-ribose) polymerase localizes to the centrosomes and chromosomes

Poly(ADP-ribose) polymerase (PARP) takes part mainly in regulation of DNA repair, thereby maintaining genomic stability in the nucleus. However, what role PARP plays in mitotic cells is not known. Centrosomes play an important role in maintaining the fidelity of chromosome distribution during cell division. Loss of these functions might cause chromosomal instability and aneuploidy. p53 and BRCA1 were recently found to localize to the centrosome at mitosis. We found that PARP is localized to the centrosomes and the chromosomes at cell-division phase and interphase by indirect immunofluorescence. Furthermore, by analysis of isolated centrosomes PARP protein was found to associate with the centrosomes during mitosis. These data suggest that PARP may be involved in maintenance of chromosomal stability.

Increased frequencies of gene and chromosome mutations after X-irradiation in mouse embryonal carcinoma cells transfected with the bcl-2 gene

Preimplantation stage mouse embryos are known to be highly sensitive to the killing effect of DNA-damaging agents such as radiation. Interestingly, however, this stage of development is well protected from radiation induction of malformation and carcinogenesis in postnatal life. In recent years, it has become clear that the stem cells of preimplantation stage embryos undergo extensive apoptosis after DNA damage. It has been postulated that this apoptosis is likely to be responsible for the resistance to malformation, by excluding cells carrying deleterious DNA damage. We have tested the possible role of apoptosis in elimination of gene and chromosome mutations in undifferentiated mouse embryonal carcinoma cell line, F9, transfected with human bcl-2 cDNA. The colony radiosensitivity of F9 cells was not affected by overexpression of the bcl-2 gene, but the apoptotic cell death was suppressed, as examined by DNA ladder assay and Hoechst staining. This suppression was accompanied by an increase in the frequencies of hprt mutation and micronucleus formation after X-irradiation. These results support the idea that maintenance of genomic integrity during early development is likely to be executed by apoptotic elimination of cells at risk.

Polar angle as a determinant of amphipathic alpha-helix-lipid interactions: a model peptide study

Various physicochemical properties play important roles in the membrane activities of amphipathic antimicrobial peptides. To examine the effects of the polar angle, two model peptides, thetap100 and thetap180, with polar angles of 100 degrees and 180 degrees, respectively, were designed, and their interactions with membranes were investigated in detail. These peptides have almost identical physicochemical properties except for polar angle. Like naturally occurring peptides, these peptides selectively bind to acidic membranes, assuming amphipathic alpha-helices, and formed peptide-lipid supramolecular complex pores accompanied by lipid flip-flop and peptide translocation. Despite its somewhat lower membrane affinity, thetap100 exhibited higher membrane permeabilization activity, a greater flip-flop rate, as well as more antimicrobial activity due to a higher pore formation rate compared with thetap180. Consistent with these results, the peptide translocation rate of thetap100 was higher. Furthermore, the number of peptides constituting thetap100 pores was less than that of thetap180, and thetap100 pores involved more lipid molecules, as reflected by its cation selectivity. The polar angle was found to be an important parameter determining peptide-lipid interactions.

The effect of caffeine on p53-dependent radioresponses in undifferentiated mouse embryonal carcinoma cells after X-ray and UV-irradiations

The effect of caffeine was studied on the radioresponses of undifferentiated mouse embryonal carcinoma cells (EC cells) with or without the functional p53. The radioresponses studied included radiosensitivity, the activation of p53, apoptosis with characteristic DNA ladder formation and cell cycle progression. An undifferentiated mouse EC cell line, ECA2, and a newly established p53-deficient EC cell line, p53 delta, were used in the present study. The status of the p53 gene did not significantly affect the colony survivals of undifferentiated EC cells to X-rays and UV. Although a post-irradiation treatment with caffeine sensitized both lines to X-rays marginally, the sensitization was prominent for UV regardless of the p53 status of the cells. The activation of a p53 responsible lacZ reporter construct was observed in stably transfected ECA2 cells after X-ray and UV irradiations. Caffeine suppressed the X-ray induced activation of the lacZ reporter, while it drastically enhanced the activation after UV irradiation. X-rays and UV readily triggered the apoptosis of ECA2 cells with the characteristic DNA ladder. Although UV-induced DNA ladder formation was enhanced by caffeine, that induced by X-rays was unaffected. Therefore, the effects of caffeine on the p53-dependent radioresponses were found to be agent specific: suppression for the X-ray induced and augmentation for the UV induced. In contrast to p53-proficient ECA2 cells, smear-like DNA degradation was observed for irradiated p53 delta cells, suggesting the presence of a mode of cell death without DNA ladder formation. UV induction of the smear-like DNA degradation was enhanced in the presence of caffeine. Regardless of the state of the p53 gene, G1/S arrest was not observed in X-ray and UV irradiated EC cells. X-ray induced G2/M arrest in both lines, which was abrogated by caffeine, while G2/M arrest after UV was unaffected by a caffeine treatment. These results indicate that the radioresponses of undifferentiated EC cells differ considerably from those of somatic cells, and that these radioresponses were modulated by a post-irradiation treatment with caffeine.

DNA sequence analysis of spontaneous tonB deletion mutations in a polA1 strain of Escherichia coli K12

By DNA sequence analysis, we have determined a spectrum of 61 spontaneous mutations occurring in the endogenous tonB gene in the polA1 strain of Escherichia coli. The overall mutation frequency was approximately 2.4-fold higher in the polA1 strain and this was attributable to enhanced rates of deletion and frameshift mutations. Among 39 deletions, a hot spot (17 mutations) was detected: a 13-bp deletion presumably directed by a 3-bp repeated sequence at its end points. The remaining 22 were distributed among 19 different mutations either flanked (16/19) or not flanked (3/19) by repeated sequences. Single-base frameshifts accounted for 8 mutations of either repeated (3/8) or nonrepeated (5/8) bases among which 6 were minus one frameshift. In contrast to previous reports, we did not frequently observe a 5'-GTGG-3' sequence in the vicinity of the deletions and frameshifts. The results presented here indicated an anti-deletion and anti-frameshift role for DNA polymerase I.

Asymmetric crossing over in the spontaneous formation of large deletions in the tonB-trp region of the Escherichia coli K-12 chromosome

The chromosomal tonB gene of Escherichia coli was used as a target for the detection of spontaneous deletion mutations. The deletions were isolated in both recA+ and recA- cells, and mutants carrying large deletions were identified because they also lacked part or all of the trp operon. The frequencies of tonB-trp deletion were 1.79 x 10(-9) and 1.09 x 10(-9) for recA+ and recA- cells, respectively. We analyzed 12 deletions from recA+ and 10 from recA- cells by cloning and direct sequencing. The deletions ranged in size from 5612 bp to 15142 bp for recA+ and from 5428 bp to 13289 for recA- cells. Three deletions from recA+ cells and five deletions from recA- cells were found to have occurred between short sequence repeats at the termini of the deletion, leaving one copy of the repeat in the mutant sequence. Seven deletions from recA+ cells and three deletions from recA- cells did not have repeats at their termini; in these cases, the DNA sequences that are adjacent to the deletion termini in the wild-type are characterized by short (2-4 bp) repeats. From these results, a model is presented for the generation of deletion mutations which involves formation of an asymmetric crossover mediated by repeated sequences of 2- to 4-bp.

An Escherichia coli topB mutant increases deletion and frameshift mutations in the supF target gene

We have improved a system to examine forward mutations that occurred in the supF gene of Escherichia coli placed on a multicopy plasmid. Using this system, we determined the mutational specificity for a topB deletion mutator in which topoisomerase III is hampered. The frequency of supF- mutations in topB strain was 4.9 x 10(-7), that is essentially the same as that in wild-type strain, 3.1 x 10(-7). Half the number of the supF- mutations were large deletions, where a specific deletion among a 10-base pair direct repeat dominated, but other types of deletions were also found. Most of the deletions were associated with the presence of directly repeated sequences capable of accounting for their endpoints. Frameshift mutations in topB strain also significantly increased compared with those of wild-type (17 vs. 2%). Base substitutions comprised 27% of the events, specificity of which in topB strain was the same as that in wild-type strain. The present data suggest that topB is a novel class of mutator that strongly induces repeated sequence dependent deletion mutagenesis and high frequencies of frameshift mutagenesis.

[Experimental study of the reaction of bone to change in blood flow]

The purpose of this study was to elucidate the effect of blood flow on bone of the lower limb experimentally. The femoral vein and artery were ligated in five to 7 week-old rabbits. The proximal thigh was then tied using an elastic cord with a 7 Kg weight. Two weeks later, local blood flow was measured by means of the hydrogen washout technique. Blood flow to the femoral diaphyseal marrow and tibial periosteum was elevated, while that to the remaining parts of the limb was reduced. After sacrificing the animals, radiographic and histological examinations were conducted. The femur and tibiofibula on the operated side were shortened. Endosteal bone formation and periosteal bone resorption were found in the femur, while periosteal bone formation were observed in the tibiofibula. The changes in blood flow were suggested to cause different reactions of the periosteum and endosteum.