Molecular cloning and expression of rat liver aminopeptidase B

We isolated, by immunological screening of a Uni-ZAP XR cDNA library constructed from rat liver mRNAs, a cDNA clone with 2212 base pairs encoding aminopeptidase B (EC 3.4.11.6). The open reading frame encodes a 649-amino acid protein with a theoretical molecular mass of 72,545 Da and bears the consensus sequence of the zinc metalloexopeptidases, indicating that the enzyme belongs to this family, which includes aminopeptidase A, aminopeptidase N, and leukotriene-A4 hydrolase. Escherichia coli SOLR cells infected with the pBluescript phagemid excised from the Uni-ZAP XR vector containing the aminopeptidase B cDNA had a high L-arginyl-beta-naphthylamidase activity. The recombinant protein was purified to homogeneity from the recombinant E. coli extracts. The enzyme had Cl--dependent aminopeptidase activity specifically restricted to the Arg and Lys derivatives and contained 1 mol of zinc per mol of the enzyme.

The Mos/mitogen-activated protein kinase (MAPK) pathway regulates the size and degradation of the first polar body in maturing mouse oocytes

Mos is an upstream activator of mitogen-activated protein kinase (MAPK) and, in mouse oocytes, is responsible for metaphase II arrest. This activity has been likened to its function in Xenopus oocytes as a component of cytostatic factor. Thus, Mos-deficient female mice (MOS-/-) are less fertile and oocytes derived from these animals fail to arrest at metaphase II and undergo parthenogenetic activation [Colledge, W. H., Carlton, M. B. L., Udy, C. B. & Evans, M. J. (1994) Nature (London) 370, 65-68 and Hashimoto, N., Watanabe, N., Furuta. Y., Tamemoto, B., Sagata, N., Yokoyama, M., Okazaki, K., Nagayoshi, M., Takeda, N., Ikawa, Y. & Aizawa, S. (1994) Nature (London) 370, 68-71]. Here we show that maturing MOS-/- oocytes fail to activate MAPK throughout meiosis, while p34cdc2 kinase activity is normal until late in metaphase II when it decreases prematurely. Phenotypically, the first meiotic division of MOS-/- oocytes frequently resembles mitotic cleavage or produces an abnormally large polar body. In these oocytes, the spindle shape is altered and the spindle fails to translocate to the cortex, leading to the establishment of an altered cleavage plane. Moreover, the first polar body persists instead of degrading and sometimes undergoes an additional cleavage, thereby providing conditions for parthenogenesis. These studies identify meiotic spindle formation and programmed degradation of the first polar body as new and important roles for the Mos/MAPK pathway.

[A basic and clinical evaluation of a new immunoradiometric assay kit for human serum tissue polypeptide antigen (TPA)]

A new immunoradiometric assay kit (IRMA) of human serum tissue polypeptide antigen (TPA) based on combination monoclonal antibodies was evaluated. Using a new TPA-IRMA, the procedure of TPA measurement was faster and the range of measurement was more wide than a conventional TPA-IRMA. 89% (76/85 cases) of patients with malignant tumor and 96.4% (27/28) of patients with metastatic malignant tumor were positively detected. This assay of new TPA-M kit is sensitive to the level of serum TPA which is corresponding to a therapy. It is concluded that a new TPA-IRMA is very useful in monitoring and assessing malignant tumors.

Mos/mitogen-activated protein kinase can induce early meiotic phenotypes in the absence of maturation-promoting factor: a novel system for analyzing spindle formation during meiosis I

Mitogen-activated protein kinase (MAPK) is selectively activated by injecting either mos or MAPK kinase (mek) RNA into immature mouse oocytes maintained in the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). IBMX arrests oocyte maturation, but Mos (or MEK) overexpression overrides this block. Under these conditions, meiosis I is significantly prolonged, and MAPK becomes fully activated in the absence of p34cdc2 kinase or maturation-promoting factor. In these oocytes, large openings form in the germinal vesicle adjacent to condensing chromatin, and microtubule arrays, which stain for both MAPK and centrosomal proteins, nucleate from these regions. Maturation-promoting factor activation occurs later, concomitant with germinal vesicle breakdown, the contraction of the microtubule arrays into a precursor of the spindle, and the redistribution of the centrosomal proteins into the newly forming spindle poles. These studies define important new functions for the Mos/MAPK cascade in mouse oocyte maturation and, under these conditions, reveal novel detail of the early stages of oocyte meiosis I.

Abnormal centrosome amplification in the absence of p53

The centrosome plays a vital role in mitotic fidelity, ensuring establishment of bipolar spindles and balanced chromosome segregation. Centrosome duplication occurs only once during the cell cycle and is therefore highly regulated. Here, it is shown that in mouse embryonic fibroblasts (MEFs) lacking the p53 tumor suppressor protein, multiple copies of functionally competent centrosomes are generated during a single cell cycle. In contrast, MEFs prepared from normal mice or mice deficient in the retinoblastoma tumor suppressor gene product do not display these abnormalities. The abnormally amplified centrosomes profoundly affect mitotic fidelity, resulting in unequal segregation of chromosomes. These observations implicate p53 in the regulation of centrosome duplication and suggest one possible mechanism by which the loss of p53 may cause genetic instability.

Mutagenic analysis of functional domains of the mos proto-oncogene and identification of the sites important for MAPK activation and DNA binding

We constructed in-frame deletion/replacement mutations in the Xenopus mos proto-oncogene that lie within conserved Mos-specific codons, but outside of the regions that are conserved among the src kinase family of genes. All gene products were assayed in vitro for kinase activity and in vivo for their ability to induce oocyte maturation, embryonic cleavage arrest and cellular transformation. Most mutations in Mos eliminated both kinase and biological activity. However, a mutation in Mos that removed two basic amino acid residues (R94 and K97) downstream from the lysine at the ATP binding site (K90) markedly enhanced autophosphorylation activity. Moreover, this mutant displayed markedly reduced biological activity, lacked transforming activity, and failed to activate mitogen activated protein kinase (MAPK). A second mutant Mos product, lacking amino acids R45-A54, displayed a five-fold increase in cellular transforming activity. This Mos mutant specifically localized to the cytoplasm; in contrast to wild-type (wt) Mos that localized to both the nucleus and the cytoplasm. These data indicate that Mos transforming activity is mediated via signalling exerted in the cytoplasm, presumably through MAPK, and that nuclear localization of the oncogene product interferes with transforming activity. We also show that amino acids R45-A54 are important for Mos DNA binding activity.

Mos overexpression in Swiss 3T3 cells induces meiotic-like alterations of the mitotic spindle

High levels of mos protooncogene product are expressed during oocyte meiotic maturation and Mos has been implicated in formation of the spindle and spindle pole. Here, we show that in Swiss 3T3 cells with 4N DNA content, high levels of Mos lead to the production of binucleated cells. The Swiss 3T3 cells in mitosis, before binucleation occurs, are anastral and the spindle poles are juxtaposed to the cell membrane. These phenotypes may be related to the meiotic process of attachment of the spindle pole to the oocyte membrane during polar body formation. The production of binucleated somatic cells could result from attachment of the altered mitotic spindle pole to the cell membrane that interferes with cytokinesis but not karyokinesis. This can explain at least one form of genetic instability that leads to altered DNA content in tumor cells.

Determination of v-Mos-catalyzed phosphorylation sites and autophosphorylation sites on MAP kinase kinase by ESI/MS

MAP kinase kinase (MAPKK), a key component of the MAP kinase cascade, is activated through phosphorylation by several protein kinases, including the oncogene v-Mos and its cellular counterpart, c-Mos. The v-Mos-catalyzed phosphorylation sites on recombinant MAPKK1 were identified by electrospray ionization mass spectrometry as S218 and S222, located within a sequence that aligns with the T loop structure of cAMP-dependent protein kinase; these are the same as the Raf-1 phosphorylation site identified previously [Alessi, D. R., et al. (1994) EMBO J. 13, 1610-1619]. Phosphorylation of these sites was kinetically ordered, with S222 preferred over S218. Intramolecular autophosphorylation of these sites was kinetically ordered, with S222 preferred over S218. Intramolecular autophosphorylation of MAPKK occurred at several residues and was increased upon the stimulation of MAPKK activity by v-Mos. Major autophosphorylation sites were residues S298 and Y300. Minor autophosphorylation sites included T23, S299, S218, and either S24 or S25. Sequence similarities were noted between MAPKK autophosphorylation sites and exogenous phosphorylation sites on MAP kinase. Phosphorylation of either S218 or S222 was sufficient for partial MAPKK activation by Mos, and phosphorylation of S222 alone was sufficient for autophosphorylation at S298 and Y300. Mass spectral analysis was also performed on MAPKK1 purified from rabbit skeletal muscle. The peptide containing S218 and S222 was observed in only a singly phosphorylated form, and the peptide containing S298, S299, and Y300 was observed in multiply phosphorylated forms, suggesting that MAPKK is only partially phosphorylated within the T loop but significantly modified in the autophosphorylation loop under physiological conditions.

Overexpression of mos oncogene product in Swiss 3T3 cells induces apoptosis preferentially during S-phase

When Swiss 3T3 cells are acutely infected with Moloney murine sarcoma virus containing the v-mos oncogene, 90% of the cells round up and detach from the monolayer (floating cells) and express high levels of v-Mos. The majority of the floating cells are generated between 30 and 70 h post infection when the cellular level of Mos reaches approximately 0.1% of the total protein. Seventy percent of the floating cells exclude trypan blue but are growth arrested with 2C or 4C DNA content, whereas the remaining floating cells with < 2C DNA content, are dead or dying, and show characteristic apoptotic phenotypes. The apoptotic cells are most likely generated from cells in S-phase since these cells are absent from the viable floating cell population and the percentage of cells with < 2C DNA approximated the expected S-phase fraction of logarithmically growing cells. In addition, 5'-bromo-2'-deoxyuridine-labeling studies showed that approximately 50% of the floating cells with typical apoptotic phenotypes were metabolically-labelled with the drug. These analyses show that cell populations in different stages of the cell cycle are differently affected by high levels of v-Mos expression and cells in S-phase appear to be uniquely sensitive and undergo apoptosis.

Similarities between somatic cells overexpressing the mos oncogene and oocytes during meiotic interphase

The mos protooncogene encodes a serine/threonine kinase and is a key regulator of oocyte meiotic maturation. After acute infection of Swiss 3T3 cells with virus containing the v-mos oncogene, cells expressing high levels of v-Mos round up and detach from the monolayer (floating cells), while cells that remain attached express 10-fold lower levels of v-Mos and are transformed. The floating cells are growth arrested with their chromosomes partially condensed in the absence of histone H1 kinase activity, while mitogen-activated protein kinase activity is very high. Collectively, these properties are similar to properties observed in maturing oocytes between meiosis I and II. In v-mos-transformed cell populations, mitogen-activated protein kinase activity is also elevated, correlating with the degree of morphological transformation and the level of Mos expression. Moreover, phosphoprotein modifications specific for M are found in both the floating cells and in v-mos-transformed cells, regardless of their cell cycle stage. One explanation for both morphological transformation and the phenotypes of the floating cells is that Mos imposes a meiotic program on different stages of the somatic cell cycle. The extent of this meiotic phenotype is proportional to the level of v-Mos expression. These results suggest that both morphological transformation and the phenotypes of the floating cells induced by Mos in Swiss 3T3 cells are related to its normal activities during oocyte maturation.

Transformation of mammalian cells by constitutively active MAP kinase kinase

Mitogen-activated protein (MAP) kinase kinase (MAPKK) activates MAP kinase in a signal transduction pathway that mediates cellular responses to growth and differentiation factors. Oncogenes such as ras, src, raf, and mos have been proposed to transform cells by prolonging the activated state of MAPKK and of components downstream in the signaling pathway. To test this hypothesis, constitutively active MAPKK mutants were designed that had basal activities up to 400 times greater than that of the unphosphorylated wild-type kinase. Expression of these mutants in mammalian cells activated AP-1-regulated transcription. The cells formed transformed foci, grew efficiently in soft agar, and were highly tumorigenic in nude mice. These findings indicate that constitutive activation of MAPKK is sufficient to promote cell transformation.

Chromophobe renal cell carcinoma: a report of two cases

Chromophobe renal cell carcinoma (RCC) is a recently established subtype of RCC, which has rarely been reported in Japan. In this communication, the authors report two Japanese cases of chromophobe RCC together with the immunohistochemical findings. The tumors were composed of sheets and cribriform glands formed by tumor cells with cloudy and reticular cytoplasm. Ultrastructurally, the cytoplasm was filled with numerous microvesicles. The tumor cells were positive for cytokeratin, epithelial membrane antigen, and Tamm-Horsfall protein. Occasionally, LeuM1-positive cells were also noted. Vimentin was negative, unlike the usual RCC. Reactivity for peanut agglutinin was more frequent than that to Lotus tetragonolobus agglutinin. The results of this study suggest that the tumor cells possessed phenotypes similar to the distal nephron rather than to the proximal tubular cells.

Ubiquitous nuclear proteins bind to 5' upstream region of major Kunitz chymotrypsin inhibitor gene in winged bean

Winged bean Kunitz chymotrypsin inhibitor (WCI) accumulates abundantly in seeds and tuberous roots of winged bean plant. In seeds, the WCI mRNA is observed transiently during seed maturation period. The WCI is encoded by a multigene family and the major WCI (WCI-3) is encoded by two nearly identical genes (WCI-3a and WCI-3b genes), in which nucleotide sequences in the 1.1 kb 5' flanking regions are about 99% homologous to each other and the transcribed regions are completely identical. Here we report the detection of two types of nuclear proteins which bind to the multiple sites in the 5' upstream region of the WCI-3a gene. One of the proteins, band 1-forming protein, also bound to cauliflower mosaic virus 35S (CaMV35S) promoter, but another protein, band 3-forming protein, did not. DNaseI footprinting analysis showed that these proteins bound to AT-rich upstream regions in the WCI-3a gene. Addition of poly(dA-dT)-poly(dA-dT) to the binding reaction inhibited the formation of the retarded bands, while poly(dI-dC)-poly(dI-dC) did not. In various organs and throughout seed maturation period, proteins with invariable binding specificities were detected, and these binding proteins met some operational criteria for high-mobility-group (HMG) proteins. These results suggest that leguminous seed AT-binding proteins reported on several seed storage protein genes may be HMG-like proteins which are present ubiquitously in plant organs.

[Characteristics of day service center clients and their families based on their medical conditions]

Clients utilizing day service centers in Hokkaido, and their families were surveyed for the purpose of analyzing present conditions of health, ADL level, family structure, motivation, activities, and changes in physical and psychosocial status. The average age of subjects was 76 years old with women generally being older than men. Most were living with their families. As to disease, cerebrovascular diseases were most common followed by hypertension and spinal-articulation diseases. Women had more hypertension problems compared to men who had more cerebrovascular conditions. Effectiveness of these day service programs were seen in the improvement of psychological functions. Persons with cerebrovascular disease had greater participation in functional rehabilitation training programs, and their ADL skills were improved.

[Effects of anesthesia on the metabolic response during pelvic surgery]

Dividing anesthesia for gynecological laparotomy into nitrous oxide-oxygen-halothane (GOF) anesthesia (group A), nitrous oxide-oxygen (GO) plus ketamine anesthesia (group B) and GOF plus epidural anesthesia (group C), we studied effects of each anesthesia on circulatory and metabolic systems. During the operation, influence on the heart rate was slight in three groups, while systolic pressure decreased significantly in group C. The lactic acid in the blood was elevated in three groups, but the elevation was least in group C. The elevation of lactic acid pyruvic acid ratio (L/P) was less in group C. The blood glucose level was elevated significantly in three groups, and it was highest in group A. On the other hand NEFA was elevated significantly in group A, while no change was noted in group B, and decreasing was noted in group C. The results indicate that no large influence of each anesthesia on the metabolic system was noted in group A and B, and its influence was the least in group C.

Hypertension in unilateral atrophic kidney secondary to ureteropelvic junction obstruction

A patient with atrophic unilateral hydronephrosis due to ureteropelvic junction obstruction associated with hypertension was successfully treated by nephrectomy. Preoperatively, plasma renin activity was elevated in both the peripheral vein and affected renal vein. Renin concentration in the resected kidney was high, and immunohistochemical localization of renin was observed along the afferent arterioles of the juxtaglomerular apparatus and in arterioles at some distance from the glomeruli.

Excess wild-type p53 blocks initiation and maintenance of simian virus 40 transformation

Wild-type (wt) murine p53 has been tested for its ability to block and reverse the transforming effects of simian virus 40 (SV40) large T antigen. Established and precrisis mouse cells overexpressing exogenously introduced wt p53 became resistant to SV40 transformation. The introduction of excess wt p53 into SV40-transformed precrisis cells reverted their transformed phenotype. However, the phenotype of SV40-transformed established cells was not reverted by excess wt p53. We conclude that an antioncogenic action of wt p53 is exerted during SV40 transformation and that in precrisis cells, the antitransforming action of wt p53 can be exerted both at initiation and during the maintenance of transformation.

Serum dipeptidyl peptidase activities as a possible marker of oral cancer

Serum glycyl-l-prolyl 4-methyl-coumaryl-7-amide (gly-pro-MCA) hydrolase (DPP IV) and L-lysyl-L-alanyl beta-naphthylamide (lys-ala-beta NA) hydrolase (assumed to be DPP II) activities were measured in patients with oral squamous cell carcinoma and healthy subjects. The mean serum DPP IV activity of all cancer patients was significantly (P less than 0.001) decreased, compared with that of healthy subjects. Although there was no significant difference between the stages by International Union Against Cancer (UICC) classification (1978), DPP IV levels tended to change dynamically, reflecting the clinical status during therapies. The serum DPP IV activity of patients with a fair prognosis was significantly elevated toward the normal range, whereas the activity of patients with a poor prognosis was significantly decreased (P less than 0.05). In contrast, the mean serum lys-ala-beta NA hydrolytic activity of cancer patients was significantly (P less than 0.001) increased, compared with that of healthy subjects, and was changed reciprocally to DPP IV activity. The correlation of these two serum enzyme activities with tumor weights also was observed in animal models using nude mice transplanted with human KB carcinoma cells and hamsters transplanted with BHK21 cells. These results indicate that these serum enzyme levels may become an aid for the diagnosis of malignant tumors and for estimating the prognosis of the patients.

The use of chitin as a new absorbable suture material--an experimental study

A comparative study of four absorbable suture materials, namely; poly-N-acetylglucosamine (Chitin), polyglycolic acid (PGA), plain catgut and chromic catgut, in terms of strength, elongation, tensile strength retention and tissue reaction, was undertaken. The straight pull strength of USP 3-0 size Chitin was over 2.6 kg, compared with PGA, which was over 3.4 kg and the catguts, which were over 2.0 kg. Chitin showed the lowest elongation among the four. The tensile strength retention (TSR) of Chitin in muscle was 45 per cent at 14 days and 7 per cent at 25 days, which was similar to that of PGA. The TSR of Chitin was maintained by 35 per cent in gastric juice, 97 per cent in bile and 100 per cent in pancreatic juice after immersion for 30 days. The corresponding values for PGA were 54 per cent, 0 per cent and 0 per cent, respectively, whereas both catguts had dissolved within 30 days. The tissue reaction of Chitin was similar to that of PGA, whereas the catguts caused more intense tissue reaction.

[Complications due to high-dose OK-432 administration into tumors and the peritoneal cavity in patients with advanced gastric cancer]

It has been assumed that a high dose of OK-432 can be safely injected into tumor tissues or intraperitoneally under general anesthesia. Among 40 patients with advanced carcinoma of the stomach, high doses of OK-432 were injected into the tumor in six and intraperitoneally in 34. Circulatory shock associated with subsequent disseminated intravascular coagulation (DIC) developed within 3 days in one of the former and in two of the latter group. Hypovolemic shock was initially considered to indicate that hypovolemia actually existed in these three patients. However, the shock state with DIC persisted even after the blood volume had been corrected. Gram-negative bacteremia was verified in two of the patients. The shock and DIC seen in these patients could have been attributed to septicemia through either the necrotic tumor or the intestinal wall showing increased permeability as a result of the drug. When and if a high dose of OK-432 is administered locally, the prophylaxis of infection seems to be of crucial importance in order to avoid such complications as those reported above.