Multiple primary cancers with microsatellite instability: report of a case

We report here a patient who developed a variety of tumors both synchronously and metachronously over a 2-year period. The involved organs were the uterus, ureter, and small and large intestines. The patient underwent open surgery 3 times and polypectomies 6 times. Postoperative histopathologic analysis showed 2 adenomas and 8 carcinomas. Genetic analysis revealed microsatellite instabilities at the tested loci in all 10 tumors, indicating that replication errors played an essential role in the tumorigenesis. Early identification of microsatellite instability could be useful for predicting development of additional primary cancers.

Constitutive expression of the thrombopoietin gene in a human hepatoma cell line

The gene of thrombopoietin (TPO) has been cloned and identified to be identical to gene of the c-mpl ligand. It is known that the mRNA of TPO is expressed in liver and kidney. However, it is not clarified which cells in the liver produce TPO. Using a human hepatoma cell line, HepG2, we demonstrated that the TPO mRNA was expressed by liver parenchymal cells without any stimulation. To clarify the regulation of the expression of the TPO mRNA in HepG2 cells by cytokines, we assessed the effects of 5 cytokines, transforming growth factor-beta 1, activin A, platelet-derived growth factor, hepatocyte growth factor, and interleukin-6. These cytokines have no significant regulative effect on the expression of the TPO mRNA in HepG2 cells. Our results suggest that liver parenchymal cells may be the TPO producing cells and also suggest that some hepatoma cells may produce TPO constitutively.

Crystal structure of Streptomyces erythraeus trypsin at 1.9 A resolution

A trypsin-like serine protease from Streptomyces erythraeus (abbreviated as SET) has been crystallized at pH 7, which is within its active pH range. The crystal structure of SET has been solved by molecular replacement using the atomic model of Streptomyces griseus trypsin (SGT), which is 37% homologous with SET, and refined to the crystallographic R factor of 0.199 for 15,878 reflections with Fo/sigma(F) > 3 between 7 and 1.9 A resolution. The final model of SET contains 1,619 protein atoms and 97 water molecules. No Ca2+ ion is present in SET apparently because (i) the two carboxylate groups from two Glu residues, which bind a Ca2+ ion in bovine trypsin (BT) or SGT, have disappeared; and (ii) a guanidino group from an Arg residue is unfavorably present in the potential binding region. There is an unusual type II beta-turn in which the third residue is Asp instead of Gly. This Asp residue is the only non-Gly residue significantly outside the allowed regions in the Ramachandran map. The three-dimensional structure of SET is essentially the same as those of other trypsins of mammalian origin. The 211 C alpha atoms of SET exhibit an r.m.s. deviation of 1.16 A with equivalent atoms of BT, and the 208 equivalent C alpha atoms between SET and SGT exhibit an r.m.s. deviation of 1.09 A. The large deviations in C alpha positions between SET and BT or between SET and SGT are mainly observed in the first domain. The conformations of the side-chains of the catalytic triad are mutually similar to each other in these three proteases. Each of the chi 1 torsion angles of the three residues is distributed within +/- 5 degrees from each corresponding mean value. The hydrogen bond distances related to the side-chains in the triad coincide fairly well, though the relative disposition of the side-chains differs by 0.1-0.6 A among SET, BT, and SGT. The hydrogen bond network concerned with Ser(195), Asp(189), and water molecules in the substrate binding pocket differs from that in BT or SGT.

Analysis of beta-ketothiolase and acetoacetyl-CoA reductase genes of a methylotrophic bacterium, Paracoccus denitrificans, and their expression in Escherichia coli

The beta-ketothiolase gene (phaA) and acetoacetyl-CoA reductase gene (phaB) were isolated from Paracoccus denitrificans. Nucleotide sequence analysis showed that they encoded proteins of 391 amino acids with a molecular mass of 40,744 Da and of 242 amino acids with a molecular mass of 25,614 Da, respectively. The predicted gene products exhibited high amino acid identities with those from other bacteria: 64.4-74.0% for the phaA gene product and 47.6-80.6% for the phaB gene product, respectively. Both genes were co-transcribed in a recombinant Escherichia coli. In addition, promoter activity was detected upstream of the phaA gene. Hence, the two genes are organized as an operon, phaA-phaB, in P. denitrificans. NADH was preferred to NADPH as a cofactor of acetoacetyl-CoA reductase.

Proliferative activity in breast carcinoma evaluated by BrdU and PCNA. Correlation with expression of p53, c-erbB-2, estrogen receptor and P-glycoprotein

The proliferative activity in 35 cases of breast carcinoma was evaluated by bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) and was compared with benign breast lesion. Overexpression of p53 and c-erbB-2 oncoprotein, presence of estrogen receptor (ER) and cellular localization of multidrug resistance gene product P-glycoprotein (P-gp) were immunohistochemically examined to investigate the relation with the proliferative activity and clinicopathologic characteristics. The mean BrdU labeling index (LI) was 12.6% and PCNA labeling rate (LR) was 33.5% in breast carcinomas, and good correlation was found between them. The proliferative activity of breast carcinomas was significantly higher than that of benign lesions. The BrdU LI correlated positively with tumor size, histologic grade, TNM stage and p53 immunoreactivity, and negatively with the presence of ER. PCNA LR correlated with histologic grade and expression of p53. p53 protein was demonstrated in 43% of the breast carcinomas and correlated with proliferative activity. The extent of p53 immunoreactivity on carcinoma cells was also related to BrdU LI. c-erbB-2 oncoprotein was demonstrated in 51% of the breast carcinomas and correlated with histologic grade. ER was found in 34% of the breast carcinomas and correlated negatively with histologic grade, lymph node metastasis and TNM stage. P-gp was observed in 49% of the breast carcinomas and no correlation was found with clinicopathologic characteristics. None of the benign lesions expressed p53 protein, c-erbB-2 oncoprotein and P-gp. BrdU is a reliable standard and a more useful tool for the evaluation of proliferative activity of breast tumors. High proliferative activity, overexpression of p53 protein and the absence of ER are considered as a high grade malignancy of breast carcinoma. Expression of c-erbB-2 oncoprotein and P-gp may be related to malignant transformation of breast tumors.

Inhibition of 1,2-dimethylhydrazine-induced oxidative DNA damage by green tea extract in rat

Following subcutaneous injection of 1,2-dimethylhydrazine (DMH), which is carcinogenic to rat colon and liver, to Sprague-Dawley rats, a significant increase of 8-hydroxydeoxyguanosine (8-OHdG) was observed in the DNA of colonic mucosa and liver. The 8-OHdG formation reached the maximal level at about 24 h after the DMII injection. On the other hand, no increase of 8-OHdG was observed in the DNA of the kidney. Drinking green tea extract (GTE) for ten days prior to the DMH injection significantly inhibited the formation of 8-OHdG in the colon. These findings demonstrate that DMH causes oxidative damage to the DNA of its target organ, and that GTE protects colonic mucosa from this oxidative damage.

Choroid plexus carcinoma in the lateral ventricle--case report

A 68-year-old male presented with choroid plexus carcinoma in the left lateral ventricle manifesting as dysarthria and gait disturbance. Magnetic resonance imaging showed a homogeneously enhanced mass in the trigone of the left lateral ventricle. Selective left posterior cerebral arteriography showed the tumor was fed by the left medial posterior choroidal artery. Detailed examinations found no evidence of an extraneural primary focus. He underwent partial removal of the tumor followed by local Lineac irradiation (50 Gy). After irradiation, the serum level of carcinoembryonic antigen decreased and the size of the residual tumor was reduced.

[An operative case of the dumbbell type retromediastinal schwannoma]

Neurogenic tumors of the mediastinum with an intraspinal component connected by a narrowed segment in the intervertebral one are generally described as dumbbell or hour-glass tumors, which need cautious and precise diagnoses and remedies, compared with other neurological tumors. A 62-year-old male was admitted to our hospital for abnormal tumor shadow in the chest X-ray film. We diagnosed this case as dumbbell type neurogenic tumor by MRI and CT. An operation was performed by modified Grillo's method: One-stage operation. With patient in prone position, L-shaped skin incision was made. Through total laminectomy of T-5 and T-6 and resection of the 6th rib, paravertebral portion of the tumor was removed, and thoracotomy in the same position under the same view enabled us to remove the residual tumor. Histopathological diagnosis was schwannoma. After the operation, no neurological complications were detected.

Acute non-lymphoblastic leukaemia with t(16;21): case report with a review of the literature

A rare case of acute non-lymphoblastic leukaemia with chromosomal t(16;21)(p11;q22) translocation was studied at the molecular level. Most of the previous reports about the translocation have been described at a karyotypic level. Blast cells of this patient expressed the TLS-ERG chimeric mRNA. The clinical, morphological, karyotypic, and immunohistochemical aspects of this leukaemia are also presented with a review of the literature.

Ultrastructural changes in the lung in Niemann-Pick type C mouse

The biochemical and morphological aspects of BALB/c mice with many features of the Niemann-Pick disease type C in man (NP-C mouse) have been studied extensively. However, the pulmonary pathology has not been studied extensively and we describe here some unique ultrastructural features of the lung in the NP-C mouse. Ultrastructurally, macrophages in younger mice contained osmiophilic dense granules and annulolamellar structures, but larger multilamellar concentric structures increased in the macrophages of older mice. In contrast, endothelial cells and type I pneumocytes showed membrane-bound bodies with dense granules and vesicular or vesiculogranular structures as well as amorphous materials. Type II pneumocytes were unremarkable throughout. Our study suggests that endothelial cells and type I pneumocytes are the major site of metabolic derangement resulting in pronounced morphological changes with granular and round membranous structures in the lungs of NP-C mouse. Alveolar macrophages with multilamellar concentric structures may be a result of disturbed disposal of surfactant material from type II pneumocytes rather than that from storage material of type I pneumocyte.

4-Aminopyridine block of the noninactivating cloned K+ channel Kv1.5 expressed in Xenopus oocytes

The blocking action of 4-aminopyridine (4-AP) on the cloned K+ channel Kv1.5 expressed in Xenopus oocytes was studied using the two-microelectrode voltage-clamp method. Application of 4-AP to the bath solution reversibly suppressed the expressed current in a voltage- and concentration-dependent manner decreasing with membrane depolarization and with a half-maximal inhibitory concentration of 0.14 mM (at +40 mV). Both block and unblock occurred mainly during a depolarization when channels were activated. With successive depolarizations, 4-AP decreased not only the peak amplitudes of the current in successive pulses, but also the current during a depolarization. Upon washout of 4-AP, the current recovered with successive depolarizations, whereas no recovery of the current was noted in the absence of depolarizations. The extent of block markedly increased with alkalization of the external solution and decreased with acidification. External application of 4-amino-pyridine methiodide, a charged form of a quaternary 4-AP derivative, did not affect the current, but internal application markedly suppressed the current, indicating the drug gained access to the channel from the cytoplasmic side. These data suggest that 4-AP crosses the membrane in its uncharged form and acts from inside of the cell in its charged form, resulting in block of the channels with higher affinity to the open state.

Biochemical and pharmacological studies on a lethal neurotoxic polypeptide from Phoneutria nigriventer spider venom

Fractionation of Phoneutria nigriventer spider venom by gel filtration and HPLC yielded a few fractions that induced different effects when administered intraperitoneally in mice. One of these fractions, PF3, was chemically characterized as a cysteine-rich polypeptide of approximately 8360 MW. Administered at 0.1 mg/kg, i.p., PF3 induced a progressive paralysis and death of mice within 30 minutes. Partial sequence analysis of PF3 revealed certain homologies with other spider toxins already described, particularly omega-AGAIIA (60%) from Agelenopsis aperta. Pharmacological characterization carried out in superfused chopped rat striatal tissues preloaded with [3H]-Dopamine ([3H]-DA) showed that PF3 (0.1 microgram/ml) decreased the [3H]-DA release induced by 20 mM K+ or 100 microM glutamate without changing the basal release. At 1 microgram/ml, PF3 inhibited 33% of the basal release of [3H]-DA; the transmitter release stimulated by K+ or by glutamate was reduced by respectively, 87% and 77% of corresponding control values. PF3 (0.1 micrograms/ml) altered the dose-response curves of glutamate (1 microM-10 mM), by reducing by 36% of its maximal effect. Naloxone (1 microM) did not influence the effect of PF3. The results indicate that PF3 inhibits the [3H]-DA release induced by membrane depolarization or that mediated by NMDA glutamate receptors. These data suggest that the mechanism of action of PF3 may involve a blockade of Ca2+ channels as well as a direct effect on the exocytotic machinery.

Design of a centrifugal blood pump with magnetic suspension

A new concept blood pump, whose impeller is suspended by permanent magnets and a mechanical pivot without seals or ball bearings, is presented in this paper. The primary aim of the blood pump is an application to implantable artificial hearts. The prototype model is of a centrifugal type with a four-vaned semiopen impeller 50 mm in diameter. Since this mechanism has no seals or ball bearings, flow stagnation or heat generation that might cause blood cell denaturation is expected to be small. The results of performance testing for the prototype model 2 were satisfactory regarding pump head and efficiency. The radial-suspension magnets and the magnetic coupling were stable. As a result, the present mechanism has been verified to be a candidate applicable to implantable artificial hearts.

Establishment and characterization of IRTA17 and IRTA21, two novel acute non-lymphocytic leukaemia cell lines with t(16;21) translocation

The t(16;21)(p11;q22) translocation is an infrequent chromosomal abnormality, but seems specific to acute non-lymphocytic leukaemia (ANLL). We established two cell lines with t(16;21)(p11;q22) from the bone marrow of a patient with ANL in relapse. Their morphological, karyotypic, immunohistochemical and genetic features are examined. Although both cell lines show monocytoid features morphologically, they express only CD13 (My7) and CD34, and neither expressed monocytoid or lymphoid markers. Reverse transcription-polymerase chain reaction showed that both cell lines expressed a similar TLS-ERG chimaeric mRNA as a result of the t(16;21)(p11;q22) translocation. As far as we know, there is no report of a leukaemia cell line with t(16;21). These cell lines represent a useful tool for leukaemia research.

Inhibition of N-methyl-N'-nitro-N-nitrosoguanidine-induced carcinogenesis by (-)-epigallocatechin gallate in the rat glandular stomach

Recently, an epidemiological study showed a lower risk of gastric cancer among people who consume a large amount of green tea. (-)-Epigallocatechin gallate (EGCG), one of the main constituents of green tea, inhibited tumor promotion by teleocidin in a two-stage carcinogenesis experiment with the use of mouse skin. The inhibitory effect of EGCG on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced carcinogenesis of the glandular stomach in rats was examined. The percentage of tumor-bearing rats in the group treated with MNNG plus EGCG was 31%, compared to 62% in the MNNG group. The difference was statistically significant (P < 0.05). To assess the effect of p.o. administration of EGCG, the gastric mucosal cellular kinetics was examined with the use of the bromodeoxyuridine labeling index, ornithine decarboxylase activity, and tissue polyamine levels. The labeling index of the EGCG treatment group decreased significantly (P < 0.05) compared to the EGCG plus MNNG treatment group. The ornithine decarboxylase activity and tissue spermidine levels were also decreased. On the other hand, the tissue putrescine and spermine levels were partly increased. These findings suggest that EGCG inhibits the cellular kinetics of the gastric mucosa during the promotion stage of MNNG-induced gastric carcinogenesis. EGCG may be useful in preventing gastric carcinogenesis. Moreover, EGCG may be applied clinically without any harmful effects and at a low cost.

Immunohistochemical staining and activity of ornithine decarboxylase in colorectal cancer

Using a new anti-human ornithine decarboxylase (anti-hODC) monoclonal antibody, the relationship between the immunoreactivity of ODC and its activity was analyzed in 21 human colorectal cancer tissues, 42 adjacent non-tumorous mucosa specimens, and 10 normal rectal mucosa samples from frozen sections and paraffin-embedded samples. A statistical significant correlation was found between the antibody reaction and the enzymic activity (P < 0.01). The immunohistochemical staining for ODC provides a new and simplified procedure for studying the activity of ODC as compared to previous methods using radioisotopes. It offers the advantages of retrospectively determining the amount of ODC in samples previously embedded in paraffin.

Effects of heart rate on left atrial contractile performance and left ventricular filling during atrial systole in dogs

Left ventricular (LV) diastolic filling and left atrial (LA) contribution have been investigated in patients with heart disease. However, many of these studies were not conducted at a constant heart rate, and the effects of heart rate remain unclear. The purpose of this study was to clarify the effects of the heart rate on left atrial contractile performance and left ventricular filling during atrial systole. The changes in LA and LV dimensions and pulmonary venous (PV) flow were determined in 9 open-chest dogs by a sonomicrometer and an electromagnetic flowmeter. With a stepwise decrease in the pacing rate from 110 beats/minute to 70 beats/minute, the LA dimension just before atrial contraction increased from 21.4 +/- 0.6 mm to 23.1 +/- 0.7 mm (p < 0.01), and the LA systolic shortening increased from 1.6 +/- 0.1 mm to 2.1 +/- 0.1 mm (p < 0.01). However, the calculated LV filling volume during atrial systole decreased from 1.9 +/- 0.3 ml to 1.4 +/- 0.2 ml (p < 0.01). The PV flow during atrial systole was directed toward the LA, and the LA influx volume from PV decreased from 0.6 +/- 0.1 ml to 0.2 +/- 0.04 ml (p < 0.01). With a decrease in the pacing rate, the LA Frank-Starling mechanism operated. However, LV filling during atrial systole decreased because of the decrease in PV flow to the LV via the LA. Thus, LA contractile performance cannot always be evaluated from LV filling.

A long-lived batch reaction system of cell-free protein synthesis

Several reaction conditions of cell-free protein synthesis such as temperatures, buffers, tRNAs, and creatine phosphate were intensively investigated and optimized to prolong protein synthesis and make it more efficiently in a batch system. As a result of these modifications, the protein synthesis reaction continued for 10 h so that about 30 micrograms of dihydrofolate reductase (DHFR) protein derived from Escherichia coli was synthesized in 1 ml of reaction mixture. In this improved system, translational reactions of other mRNAs such as rabbit beta-globin, Xenopus beta-globin, and tobacco mosaic virus RNA also continued for about 10 h. In addition, protein synthesis directed by uncapped dhfr mRNA containing a viral cap-independent translation initiation-mediating sequence continued for 10 h, resulting in the synthesis of 18 micrograms of DHFR protein per milliliter of reaction mixture.