Posttranscriptional regulation of the c-myb proto-oncogene in estrogen receptor-positive breast cancer cells

We have determined that expression of the c-myb proto-oncogene is associated with estrogen receptor (ER) status and not with tumor progression in human breast epithelial cells. Analysis of normal, immortalized, nontumorigenic, and tumorigenic mammary epithelial cells showed that only ER+ tumor cell lines expressed readily detectable levels of c-myb mRNA and a Mr 75,000 protein that was the same size as the c-myb transcripts and protein products present in hematopoietic cells. In this report we show that c-myb mRNA and protein levels are down-regulated during estrogen withdrawal. A 20-fold increase in c-myb mRNA and protein expression was observed upon addition of beta-estradiol to the culture medium. Nuclear run-on transcription analyses showed that c-myb was transcribed at the same rate in the presence and absence of estrogen, suggesting that c-myb mRNA accumulation was regulated at a posttranscriptional level. To provide additional evidence that c-myb mRNA was dependent on ER expression, we examined c-myb mRNA levels in MCF-7 cells selected for resistance to antineoplastic drugs. c-myb expression was decreased only in cell lines that showed concomitant loss of ER expression. Moreover, c-myb mRNA was expressed and modulated by estrogen in ER-, MDA-MB-231 cells stably transfected with a human ER gene. When considered together, these data indicate that c-myb mRNA levels are regulated by estrogens and further suggest that this proto-oncogene plays a role in the biology of ER+ breast tumor cells.

Synthesis and conformational investigation of tandem repeat sequence in RNA polymerase II

The largest subunit of RNA polymerase II has a very interesting sequence in the C-terminus; that is, a tandem repeat sequence of Ser-Pro-Thr-Ser-Pro-Ser-Tyr consisted of proline residues and three kinds of residues having side-chain hydroxyl groups. Although lack of this tandem repeat is a lethal event in vivo, its functional role is unclear. The sequential polypeptide corresponding to this tandem repeat, poly(Ser-Pro-Thr-Ser-Pro-Ser-Tyr), was synthesized and its conformation was investigated by circular dichroism comparing to the monomeric heptapeptide. In addition, the theoretical conformational analysis based on the molecular mechanics was tried for the heptapeptide in the repeating unit and the periodic polyheptapeptide corresponding to the tandem repeat sequence. These results suggested the possibility that the tandem repeat contains a kind of super conformation composed of the repetitive turn structure in the native state. The characteristic repetitive turn structure would be the key of its function mechanism.

Small depressed cancer of the large bowel: report of three cases

This report describes three patients in whom colonoscopy detected small depressed cancers (without an elevated component) that had invaded the submucosa. They represent 0.4% (3/884) of all patients with invasive cancers and 3% (3/101) of patients with submucosal cancers in the National Cancer Center Hospital between January 1990 and February 1994. This type of cancer may have been overlooked in the past because of its small, flat nature. A slight deformity of the lumen, a faint color change (slightly reddish), and a loss of a vascular network pattern were important colonoscopic findings. Small depressed cancers may follow a different pathway to advanced cancer than polypoid cancers, although both pathways are included in the adenoma-carcinoma sequence. We should be aware of these lesions in our efforts to detect colorectal cancers in the early stage.

Lansoprazole for maintenance therapy of peptic ulcer disease: weekend full-dose or everyday half-dose administration?

Seventy-one patients with peptic ulcer (44 gastric ulcer and 27 duodenal ulcer patients) were enrolled in this study. After the ulcers had healed with 2 months of treatment with lansoprazole (LPZ) 30 mg/day, patients were divided into two groups: 43 in the half-dose q.d. group and 28 in the weekend full-dose group. Fourteen (23%) of the 43 patients in the half-dose q.d. group and 14 of the 28 (50%) in the weekend full-dose group failed to continue taking the drug for 6 months owing to poor compliance (p < 0.05). None of the 30 patients who continued to take the maintenance dose of LPZ experienced ulcer recurrence during the 6-month follow-up period, whereas 71% of the patients who stopped taking LPZ experienced recurrence (p < 0.01). In conclusion, maintenance therapy using the half-dose q.d. administration schedule was superior to weekend full-dose administration because of the better patient compliance and a lower ulcer recurrence rate.

Immunohistochemical and biochemical detection of low density lipoprotein receptors in cultured rat mesangial cells

The expression of low density lipoprotein (LDL) receptors by cultured rat mesangial cells was demonstrated using immunohistochemical and biochemical methods. Using a mouse monoclonal anti-human LDL receptor antibody, the immunofluorescence technique was applied to cultured mesangial cells and showed granular staining. Immunoblotting analysis of the membrane fraction of cultured mesangial cells showed a single band with a protein of approximately 130,000 molecular weight. In addition, [125I]LDL binding and the uptake of [125I]LDL by cultured mesangial cells were studied. Binding and uptake both reached an equilibrium after about 30 min of incubation. A 50% reduction in [125I]LDL (20 micrograms protein/ml) binding and uptake occurred when unlabelled LDL was added to cultures at 20-40 micrograms protein/ml. Addition of high density lipoprotein without apoE to the culture medium did not induce competitive inhibition of [125I]LDL binding and uptake by mesangial cells. These findings suggest that cultured mesangial cells have the capacity to express an LDL receptor that regulates the cellular uptake of LDL.

Stimulatory effect of angiotensin II on calcium efflux from cultured bovine adrenal chromaffin cells

The effect of angiotensin II on Ca2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Angiotensin II (10(-7)M) increased the intracellular free Ca2+ level ([Ca2+]i) to a peak in the presence or absence of extracellular Ca2+, followed by decrease with time. Angiotensin II (10(-9)-10(-6)M) also stimulated 45Ca2+ efflux from cultured bovine adrenal chromaffin cells in a concentration-dependent manner. Its stimulatory effect on 45Ca2+ efflux was inhibited by the angiotensin II antagonist [Sar1, Ile8]-angiotensin II or [Sar1, Val5, Ala8]-angiotensin II. The increase in angiotensin II-stimulated 45Ca2+ efflux was dependent on the extracellular Na+ concentration. Angiotensin II also increased 22Na+ influx into the cells. These results indicate that stimulation of the angiotensin II receptor induces extracellular Na(+)-dependent Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably by acceleration of Na+/Ca2+ exchange.

Muscarinic receptor-mediated calcium efflux from cultured bovine adrenal chromaffin cells

The effect of stimulation of the muscarinic receptor on Ca2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Acetylcholine (ACh) increased the uptake of 45Ca2+ and [Ca2+]i whose levels decreased with time after reaching peaks. It also enhanced the efflux of 45Ca2+ from the cells. Its effect was inhibited by the specific muscarinic receptor antagonist atropine (Atr), but not by the nicotinic receptor antagonist hexamethonium (C6). The increase in muscarine (Mus)-stimulated 45Ca2+ efflux was reduced concentration-dependently by deprivation of extracellular Na+. These results suggest that muscarinic stimulation of the ACh receptor stimulates Na+/Ca2+ exchange in cultured bovine adrenal chromaffin cells.

Osteoclastic resorption of apatite formed on apatite- and wollastonite-containing glass-ceramic by a simulated body fluid

We immersed mirror-polished apatite- and wollastonite-containing glass-ceramic (A-W GC) disks in a simulated body fluid (SBF) for 5 days to form bonelike apatite on their surface. Neonatal rabbit bone cells were cultured on these or on plain A-W GC disks for 10, 24, and 48 h. We observed the substrates by scanning electron microscopy after treating them with pronase E plus EDTA to remove all cells except osteoclasts. Osteoclasts with a non-motile appearance formed no lacunae on the plain A-W GC, whereas on the bonelike apatite formed on A-W GC by the SBF, actively moving osteoclasts made many tracklike resorption lacunae. These were evident even after 10 h of culture and became more extensive after longer culture periods. The bonelike apatite was therefore a more suitable medium than plain A-W GC for maintaining osteoclast activity. This study demonstrated in vitro osteoclastic resorption of bonelike apatite formed on A-W GC by an SBF. It suggests that the apatite layer, through which a surface-active ceramic bonds to bone in vivo, can be resorbed by osteoclasts and subjected to bone remodeling.

Ionic factors affecting the association of tyrosine hydroxylase with chromaffin granules in the adrenal medullary cell

Chromaffin cells were treated with digitonin in medium containing various ions and the efflux of tyrosine hydroxylase from these permeabilized cells was then determined to elucidate a possible influence of cytoplasmic ionic environment on the association of this enzyme with the chromaffin granule. The enzyme efflux was observed with a distinct lag during exposure to low concentrations of digitonin in the medium containing isotonic sucrose. In contrast, a larger extent of the enzyme efflux was observed without any notable delay in the presence of isotonic NaCl. The results were thought to indicate the possibility that the dissociation of soluble enzyme from the granule surface within the permeabilized cells might occur in the presence of NaCl. Furthermore, the interaction between tyrosine hydroxylase and isolated chromaffin granule membranes was directly examined, and this interaction was shown to be inhibited by NaCl. However, the enzyme-granule membrane interaction was also inhibited by KCl and choline chloride. It therefore seems possible to consider that the inhibitory action of NaCl on the association of soluble enzyme with the granule may not be due to the specific action of Na+, but presumably due to the non-specific chaotropic effect of Cl-. On the other hand, the enzyme efflux was markedly reduced by the presence of Ca2+ in the permeabilizing medium, but the enzyme-granule membrane interaction was not affected by Ca2+ at the same concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Depression of cytotoxicity of nonparenchymal cells in the liver after surgery

BACKGROUND

The nonparenchymal cells (NPCs) of the liver have a strong cytotoxic activity. Our hypothesis is that their activity, which prevents metastases to the liver, may be impaired after operation.

METHODS

First, Sprague-Dawley rats underwent either a sham operation consisting of only a laparotomy (group L, n = 10), a laparotomy and resection of a portion of the small intestine (group R, n = 10) or no operation (group C, n = 10). After 2 days liver NPCs were isolated and divided into two fractions, large and small NPCs. The cytotoxicity of the liver NPCs and of the circulating blood mononuclear cells (BMC) was assessed. Second, we measured the growth of tumor metastases 14 days after the inoculation of a cell line (MRMT-1) into the portal vein of rats undergoing similar surgical stress (group Rm, n = 10 and group Lm, n = 10).

RESULTS

The natural killer cell activity (anti-YAC-1) of large NPCs was 38% in group R, which was significantly less (p < 0.002) than that in groups L (72%) and C (83%). Small NPCs showed reduced natural killer activity in groups R and L (26% and 35%, respectively) compared with that in group C (70%) (p < 0.02). The natural killer cell activity of BMCs was similar in each group, and the lymphokine-activated killer cell activity (by anti-EL4) did not change in either the NPCs or BMCs. In the second experiment the area of the tumors occupied in the liver in the group Rm rats was significantly greater compared with that in the group Lm rats (p < 0.01).

CONCLUSIONS

Surgical stress depressed the cytotoxic activity of liver NPCs and enhanced the growth of metastatic liver tumors. This suggests the possibility that perioperative immunotherapy might be clinically useful in the future to prevent liver metastases after gastrointestinal surgery.

Intrapulmonary lymph nodes

We report two cases of intrapulmonary lymph nodes detected by a chest roentgenogram or CT scan. The first patient was a 61-year-old fisherman referred complaining of cough and hemosputum. Chest roentgenogram showed a subpleural small nodular shadow at the superior segment of the right lower lobe. Thoracotomy showed a small anthracotic lymph node. The other case was a 68-year-old female patient admitted for further examination of a subpleural small nodular shadow at the latero-basal segment of the left lower lobe detected on a chest CT scan. Thoracoscopic surgery revealed that the black nodule was an anthracotic lymph node. The appearance of an intrapulmonary lymph node on radiological examination is rare, however, it should be considered in the differential diagnosis of a solitary or multiple peripheral pulmonary nodules in adults. A small nodular shadow should be resected if malignancy is suspected though not proven. Subpleural intrapulmonary lymph node warrants thoracoscopic surgery.

Stimulatory effect of pituitary adenylate cyclase-activating polypeptide on catecholamine synthesis in cultured bovine adrenal chromaffin cells: involvements of tyrosine hydroxylase phosphorylation caused by Ca2+ influx and cAMP

In cultured bovine adrenal chromaffin cells, pituitary adenylate cylase-activating polypeptide (PACAP) stimulated [14C]catecholamine synthesis from [14C]tyrosine (but not from [14C]DOPA) in a concentration-dependent manner, causing maximal stimulation at 10(-7) M. The stimulatory action of PACAP was not affected by staurosporine (an inhibitor of protein kinase C) or in the cells in which protein kinase C was down-regulated by prolonged exposure to TPA (an activator of protein kinase C), whereas it was partially attenuated in Ca(2+)-free medium. PACAP (10(-7) M) increased the formation of [3H]inositol phosphates, [Ca2+]i and 45Ca2+ uptake as well as cAMP. The peptide also stimulated the phosphorylation of tyrosine hydroxylase, the enzyme catalyzing the rate-limiting step in catecholamine synthesis. Catecholamine synthesis and tyrosine hydroxylase phosphorylation stimulated by the maximal effective concentration of dibutyryl cAMP or high K+, which activates Ca2+ uptake, were further enhanced by PACAP, suggesting that both cAMP- and Ca(2+)-dependent protein kinases may be involved in the stimulation of tyrosine hydroxylase phosphorylation and catecholamine synthesis caused by PACAP.

Mechanism of histamine-induced calcium efflux from cultured bovine adrenal chromaffin cells: possible involvement of an Na+/Ca2+ exchange mechanism

The effect of stimulation of the histamine receptor on Ca2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Histamine (10(-5) M) increased the intracellular free Ca2+ ([Ca2+]i) to a peak in the presence or absence of extracellular Ca2+, followed by decrease with time. Histamine (10(-8)-10(-5) M) also stimulated 45Ca2+ efflux from cultured bovine adrenal chromaffin cells in a concentration dependent manner. Its stimulatory effect on 45Ca2+ efflux was inhibited by the specific histamine H1 receptor antagonist mepyramine. The increase in histamine-stimulated 45Ca2+ efflux was inhibited by deprivation of extracellular Na+ and by the Na+/Ca2+ exchange inhibitor amiloride. In addition, histamine stimulated 22Na+ influx into the cells, and this action was inhibited by amiloride. These results suggest that stimulation of the histamine H1 receptor regulates Na+/Ca2+ exchange in cultured bovine adrenal chromaffin cells.

Use of intra-operative ultrasonography to detect a small foreign body in the soft tissue of the upper lip

Real-time ultrasonography was used to detect a small foreign body (a broken tip of a barbed broach) which had migrated into the upper lip of a 26-year-old female from the bone defect of the upper canine apex during root canal treatment 10 months previously. Intra-operative use of ultrasound was of great-help in clarifying the positional relationship between the foreign body and the surgical instruments used, and lead to a satisfactory result.

Changes in joint fluid after total arthroplasty. A quantitative study on the rabbit knee joint

Quantitative and time dependent changes in joint fluid after total arthroplasty were investigated by applying a new dilution method to a rabbit model of total knee replacement. The joint fluid volume and total protein concentration had increased by 2 weeks after arthroplasty, reached their maximum values at 4 weeks, and decreased by 12 weeks when they were similar to the control levels. The hyaluronic acid concentration and its mean molecular weight however, were lowest 2 weeks after operation and gradually increased by 12 weeks, although the recovery was then still incomplete. Histological examination of the newly formed capsular tissues revealed both acute and chronic inflammations, the latter including granulomatous reactions to polyethylene wear particles. These results provide fundamental information not only on the biological response of periarticular tissues to total arthroplasty but also on the friction, lubrication, and wear of prosthetic joints.

Combined treatment of autoimmune MRL/MP-lpr/lpr mice with a herbal medicine, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to) plus suboptimal dosage of prednisolone

Therapeutic effects of combined treatment with a Chinese medicine prescription, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT) and suboptimal doses of prednisolone (PSL) on pathological findings of autoimmune-prone MRL/lpr mice were examined. Six-week-old MRL/lpr mice were treated orally with 1000 mg/kg of NYT, 0.5 or 2 mg/kg of PSL, 1000 mg/kg of NYT plus 0.5 or 2 mg/kg of PSL (combined treatment) or solvent only (control) six times per week. The rates of signs and symptoms of autoimmune disease (lymphadenopathy, proteinuria, dermatitis, loss of hair) were suppressed significantly in groups given PSL (2 mg/kg) alone, NYT alone and combined treatment with PSL (2 mg/kg) plus NYT (1000 mg/kg) compared with control, respectively, whereas treatment with PSL (0.5 mg/kg) alone did not inhibit their occurrence. ConA response and IL-2 production were also improved significantly in lymphocytes of mice given the combined treatment. Interestingly, treatment with NYT alone enhanced further the augmented IFN-gamma production in MRL/lpr mice but the combined treatment suppressed such an augmented production. The combined treatment dramatically reduced the level of anti-DNA antibodies in serum of MRL/lpr mice. By contrast, NYT alone treatment had no effect on autoantibodies production. These results suggest that combined treatment with NYT plus a suboptimal dose of PSL could be effective for systemic lupus erythematosus without severe side-effects.

[A case report: multiple liver metastasis from gastric cancer responding to intraarterial infusion of sequential low-dose MTX and 5-FU]

A 75-year-old man with gastric cancer having multiple liver metastases was given intraarterial infusion therapy with sequential low-dose MTX (30 mg/body) and 5-FU (1,000 mg/body) for metastatic liver tumors one month after the primary gastric tumor was resected. This therapy was given once a week on admission and every two weeks while an outpatient. A total of 18 courses of this therapy produced marked regression and necrosis of liver metastases. The effect was thus rated as partial response. This patient survived 15 months after surgery. These results indicate that intraarterial infusion therapy with sequential low-dose MTX and 5-FU may be effective in multiple liver metastasis from gastric cancer.

Inhibition by ouabain of palytoxin-induced catecholamine secretion and calcium influx into cultured bovine adrenal chromaffin cells

The effect of ouabain on palytoxin (PTX)-induced catecholamine secretion from cultured bovine adrenal chromaffin cells was examined in relation to its effect on calcium (Ca2+) influx into the cells. Ouabain showed concentration-dependent inhibition of catecholamine secretion induced by PTX. Ouabain also inhibited [45Ca]2+ influx induced by PTX, this inhibition being parallel with that of catecholamine secretion. The inhibitory effects of ouabain on PTX-induced catecholamine secretion and [45Ca]2+ influx were both overcome by increasing the concentrations of PTX, indicating that ouabain inhibited the actions of PTX in a competitive manner. These results suggest that the ouabain-sensitive (or-binding) site on the cell membrane might be the target site of action of PTX, which causes an increase in Ca2+ permeability and initiation of catecholamine secretion.

The pattern of respiratory infection in patients with lung cancer

We examined retrospectively the pattern of respiratory infection in 579 patients with lung cancer admitted to Nagasaki University Hospital during the past 15 years. A total of 139 patients (24.0%) developed respiratory infection. The rates of pulmonary infection associated with large (36.2%) and small cell carcinomas (33.6%) were significantly higher than those with squamous cell carcinoma (26.0%) and adenocarcinoma (17.3%). Advanced stages of lung cancer were associated with higher complication rates (stage I: 6.3%, stage II: 15.9%, stage III: 27.9%, and stage IV: 33.8%). Deceased patients showed a significantly higher rate of pulmonary infection than alive patients during the period of investigation. Isolated organisms in excess of 10(7) cfu/ml in sputum or 10(4) cfu/ml in bronchial aspirate were mainly gram-negative bacteria (68.8%), such as Haemophilus influenzae, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter sp. and Pseudomonas aeruginosa. The number of patients infected with gram-positive bacteria increased markedly after 1982. Our results suggest that a successful control of pulmonary infection associated with lung cancer is important in improving the prognosis of lung malignancy.

[Strategy of treatment for pancreatic and biliary cancer with special reference to immunotherapy]

A new therapeutic strategy for pancreatic and biliary cancer is needed because of its poor prognosis. We presented the results of adoptive immunotherapy using induced cytotoxic T-cells for pancreatic and biliary cancer as well as extracorporal extended right hepatectomy with resection of the inferior caval vein for intrahepatic biliary cancer. We expect that these new strategies may contribute to prognostic improvement of pancreatic and biliary cancer.

Tertiary structure of erabutoxin b in aqueous solution as elucidated by two-dimensional nuclear magnetic resonance

The three-dimensional structure of erabutoxin b, a short-chain neurotoxic peptide purified from the venom of the sea snake Laticauda semifasciata, was determined in aqueous solution by two-dimensional proton nuclear magnetic resonance and simulated annealing-based calculations. On the basis of 883 assigned nuclear Overhauser effect (NOE) connectivities, 676 final distance constraints were derived and used together with 38 torsion angle (phi, chi 1) constraints, four distance constraints derived from disulfide bridges and 30 distance constraints derived from hydrogen bonds. A total of 14 converged structures were obtained from 50 runs of calculations. The atomic root-mean-square difference about the mean coordinate positions (excluding the residues 18 to 22) is 0.60 A for backbone atoms (N, C alpha and C'). The protein consists of a core region from which three finger-like loops emerge outwards. It includes a short, two-stranded antiparallel beta-sheet of residues 2 to 5 and 13 to 16, a three-stranded antiparallel beta-sheet involving residues 23 to 30, 35 to 41 and 50 to 56, and four disulfide bridges in the core region. Comparison with two crystal structures of erabutoxin b at 1.4 A and 1.7 A resolution indicated that the solution and the crystal structures were very similar, but less defined regions were observed at the localized region of the tip of the central loop and the outside of the third loop in solution. Other short-chain alpha-neurotoxins showed structural characteristics similar to those of erabutoxin b.

Ca2+ inactivation of voltage-dependent Na+ channels in cultured bovine adrenal chromaffin cells: further studies on inhibition of veratridine-induced catecholamine secretion by external Ca2+

The stimulatory actions of veratridine (VTD) on catecholamine secretion and Na+ influx in cultured bovine adrenal chromaffin cells were studied in the presence of high concentrations of Ca2+ in the incubation mixture. Catecholamine secretion evoked by VTD was reduced by elevating the external Ca2+ concentration to higher than 2 mM. Under the same conditions, VTD-stimulated 22Na+ uptake into the cells was also reduced by elevating the extracellular Ca2+ concentration. In contrast, the secretory action of VTD was not significantly suppressed by preloading Ca2+ to the cells. Furthermore, the effects of extracellular Ca2+ on the sensitivities of the cells to VTD and tetrodotoxin (TTX) were examined, and neither their sensitivities to VTD nor those to TTX were shown to be significantly altered by elevating the Ca2+ concentration in the incubation mixture. These results seem to indicate that the elevation of extracellular Ca2+ concentration may cause the inhibition of VTD-induced catecholamine secretion as a consequence of the inactivation of voltage-dependent Na+ channels, and suggest that Ca2+ may directly act on the cell surface, and the site of Ca2+ action is presumably distinct from the sites of both VTD and TTX actions in the plasma membranes of adrenal chromaffin cells.