Antimetastatic activity of lipopolysaccharide against a NK-resistant murine fibrosarcoma

An intravenous injection of bacterial lipopolysaccharide (LPS) into mice exerted prominent antimetastatic activities against a NK-resistant weakly immunogenic NFSa fibrosarcoma. The number of visible metastases in the lung was increased by a pretreatment of anti-asialoGM1 (asGM1) antibody or silica, but pretreatment of asGM1 antibody or silica scarcely affected the antimetastatic activities of LPS. The pulmonary retention of radiolabeled tumor cells showed that LPS accelerated the detachment of the tumor cells from the lung, and that this acceleration was not suppressed by anti-asGM1 antibody. Sialic acids of lung endothelial cell surface, essential components of various receptors, was diminished by the i.v. injection of LPS. These results suggested that the antimetastatic effect of LPS against NK-resistant NFSa cells was partly the result of modulations of lung endothelial cell surface.

The discriminative effects of nicotine and their central sites in rats

The mediations in the central sites of the discriminative effects of nicotine were studied. Rats were trained to discriminate between the effects of nicotine at 0.5 mg/kg, sc and saline under a fixed ratio 10 schedule, for food reinforcement in a 2-lever operant chamber situation. After the establishment of discrimination behavior, guide cannulae were implanted bilaterally into the lateral ventricle (n = 10), the nucleus accumbens (n = 11), the ventral tegmental area (n = 7), and the dorsal hippocampus (n = 9). In substitution tests, nicotine at 100 and 120 micrograms per rat administered into the lateral ventricle and this drug at 100 micrograms per rat administered into the nucleus accumbens substituted for subcutaneous nicotine. On the other hand, neither nicotine at 10-80 micrograms per rat administered into the ventral tegmental area, nor this drug at 5-20 micrograms per rat administered into the dorsal hippocampus substituted for the subcutaneous nicotine. In antagonism tests, mecamylamine was administered into each brain area in combination with nicotine at 0.5 mg/kg, sc. Mecamylamine at 180 micrograms per rat administered into the nucleus accumbens blocked the discriminative effects of the subcutaneous nicotine while mecamylamine, administered into the ventral tegmental area and the dorsal hippocampus, did not. These results may indicate that the discriminative effects of subcutaneous nicotine are at least partially mediated in the nucleus accumbens.

Significance of platelets in an antimetastatic activity of bacterial lipopolysaccharide

Recently we reported an antimetastatic activity of bacterial lipopolysaccharide (LPS) on a NK-cell-resistant murine fibrosarcoma (NFSa). Here we investigate and report the mechanistic significance of platelets in this activity. The number of circulating platelets was reduced to 63% of the control 3 days after an i.v. injection of 1.0 micrograms LPS, and then recovered to the level of control at day 10. Aggregation efficiency of platelets was impaired by LPS. The number of metastatic lung colonies after an i.v. injection of tumor cells was maximally reduced to 2.2% of the control at day 3 and increased in proportion to the recovery of platelet number. Neuraminidase (Ndase), which caused a non-immunological thrombocytopenia, also inhibited lung metastasis when injected prior to an i.v. tumor cell challenge. LPS and Ndase showed an identical pattern against five other syngeneic tumors; these agents inhibited lung metastases of the FSa fibrosarcoma and the SCC VII squamous cell carcinoma but failed to inhibit those of the NR-S1 squamous cell carcinoma, the MMCa#4 mammary adenocarcinoma and the NR-PG parotid gland tumor. All the three cells which were not responsive to any agents possessed a high aggregating activity of platelets while the other three tumors responsive to both agents did not show a detectable level of this activity. Platelet transfusion failed to modify the antimetastatic activity of LPS. These results suggest that platelets play an important role in the antimetastatic activity of LPS, though whether the role is principal or assistant remains to be seen.

Involvement of prostaglandins and renal haemodynamics in salt-sensitivity of young spontaneously hypertensive rats

OBJECTIVES

To clarify the involvement of prostaglandins and renal haemodynamics in the pathogenesis of salt-induced hypertension.

DESIGN

Young (6-week-old) spontaneously hypertensive rats (SHR), a salt-sensitive hypertensive model, were used.

METHODS

The effect of long-term (4-week) administration of cicletanine (50 mg/100 g in the diet), which stimulates prostaglandins synthesis, was examined concerning the development of hypertension in young SHR fed on 8% salt-containing diet. Whether the cyclo-oxygenase inhibitor indomethacin (3.0 mg/kg per day for the last 4 days of the treatment) attenuates the hypertension was also studied. Renal haemodynamics were examined by clearance of inulin (glomerular filtration rate) and para-aminohippurate (renal plasma flow).

RESULTS

Salt loading significantly accelerated the development of hypertension, and the salt-induced blood pressure rise was significantly attenuated by cicletanine, although cicletanine did not attenuate the spontaneous development of hypertension. The hypotensive effect of cicletanine was abolished by indomethacin. Glomerular filtration rate and renal blood flow were not changed with these treatments. However, the changes in renal vascular resistance were parallel to those in mean blood pressure: it was increased with salt loading, reversed by cicletanine and increased by indomethacin. Salt loading decreased urinary prostaglandin E2, cicletanine reversed the effect of salt loading and indomethacin inhibited the effect of cicletanine.

CONCLUSIONS

The present findings suggest that the abnormality in prostaglandin E2 contributes to the increased salt sensitivity in young SHR, probably through renal haemodynamic changes.

Effect of prostaglandin E on the redistribution of lysosomal enzymes in caerulein-induced pancreatitis

The redistribution of cathepsin B, a representative lysosomal enzyme, from the lysosomal pellet to the zymogen pellet in subcellular fractions and the colocalization of cathepsin B with digestive enzymes within acinar cells have been found during the early stage of caerulein-induced acute pancreatitis in the rat. This study investigated the protective effects of prostaglandins E1 and E2 on the exocrine pancreas in this experimental pancreatitis. Prostaglandin E2, but not E1, prevented the redistribution of cathepsin B along with the hyperamylasemia, and the increase in amylase and trypsinogen in the acinar cells in almost a dose-dependent manner, particularly at a dose of 100 micrograms/kg.hr of continuous infusion. These results suggest that subcellular organelle fragility is closely related to the pathogenesis of acute pancreatitis, and that prostaglandin E2 has an important cytoprotective effect on biological membranes as a stabilizer of lysosomal membrane.

Angiographic retrieval of foreign bodies in pulmonary artery: a report of three cases

Three cases of percutaneous retrieval of foreign bodies that migrated into the pulmonary artery are described in this paper. All of the intravascular foreign bodies were attributed to SVC catheters for intravenous hyperalimentation (IVH) therapy, an accidentally cut strip of indwelling SVC catheter in two patients and a fragment of guide wire used for the insertion of the SVC catheter in one patient. They were all successfully removed by fluoroscopic angiographic procedures using a snare loop retriever and grasping forceps. The technical aspects of the procedures are discussed here.

Independent regulation of human D-type cyclin gene expression during G1 phase in primary human T lymphocytes

Cyclins and cyclin-dependent kinases are critically involved in controlling cell cycle progression in virtually all cells. The recent identification of candidate G1 cyclins in mammalian cells has been a major advance in this field, but the exact functions of these cyclins are unknown. The expression of three D-type cyclins (D1, D2, and D3) was investigated in primary human T lymphocytes as these cells were induced to leave G0, traverse G1, and enter S phase by T cell-specific mitogens. G0 phase T cells expressed low levels of cyclin D2, but not cyclin D3. Treatment of these cells with phytohemagglutinin and 12-O-tetradecanoylphorbol-13-acetate in the presence of fetal calf serum resulted in rapid induction of cyclin D2 RNA in early G1 and slower induction of cyclin D3 in late G1. Cyclin D1 was not detected in T cells under any condition tested. Treatment of T cells with hydroxyurea to arrest cells at G1/S did not block induction of either D2 or D3. However, arrest of cells in mid G1 with deferoxamine blocked D3 expression without affecting D2. Cyclosporin A blocked the induction of both cyclin D2 and D3. Polyclonal antisera were prepared in rabbits against both cyclin D2 and cyclin D3 glutathione S-transferase fusion proteins and used to examine cyclin D2 and D3 proteins in [35S]methionine-labeled T cells. Protein levels were found to correlate closely with RNA levels for both cyclins. No detectable histone H1 kinase activity could be precipitated with either cyclin. However, several cellular proteins were observed to coprecipitate with the cyclins, including several proteins that were observed to associate only with D3. These results indicate that striking differences exist in the induction and regulation of two candidate G1 cyclins in human T cells and suggest that these cyclins could participate in multiple cell cycle checkpoints during G0, G1, or S phase.

[Clinical utility of Gd-DTPA subtraction MR imaging for spinal bone metastasis]

Based on reports that Gd-DTPA contributes to the detection of tumors, we used it in 31 cases (97 lesions) of spinal bone metastases. The result was that Gd-DTPA increased the intensity of tumors and the surrounding bone marrow to almost the same level in 53%. To show the metastases clearly, an existing subtraction command system was utilized. The technique included the pixel-by-pixel method, to obtain a Gd-DTPA T1-weighted image (T1WI) subtracted by the original T1WI. The detectability of the subtraction image was improved up to 96%, but was less than the original T1WI (99%). Because of the different imaging rationale between two methods, a means to assess the quality of diagnosis must be proposed. To check the normal background, the same kind of postprocessing was performed in 21 patients without malignancy. Gd-DTPA perfusion was highest in the paravertebral veins, moderate in muscles and epidural fat, and lowest in the spinal cord, intervertebral disk and bone cortex. Gd-DTPA enhanced subtraction MR imaging provides a new diagnostic tool to detect and to assess bone metastasis.

Linear lichen planus mimicking creeping eruption

A 42-year-old woman was referred to our hospital with a linear eruption on her right flank of two months duration. Because she had eaten loach-fish a month before she noticed the eruption, a creeping eruption due to Gnathostoma spp. was initially suspected, but the histological findings of the biopsy specimens showed typical features of lichen planus. Linear lichen planus is discussed based on the cases accumulated in the literature regarding the distribution of Blaschko lines.

Enhancement of vasoconstrictor response by a noncalcemic analogue of vitamin D3

To clarify the effects of active vitamin D3 on pressor and vascular responses to vasoconstrictor substances, we studied pressor responses to the intravenous injection of norepinephrine or angiotensin II (Ang II) and vasoconstrictor responses to norepinephrine. Sprague-Dawley rats were given 1,25-dihydroxyvitamin D3 subcutaneously (200 ng/kg per day) for 14 days. The administration of 1,25-dihydroxyvitamin D3 augmented the pressor responses to norepinephrine and Ang II in conscious rats and was associated with a significant increase in serum calcium concentration (11.0 +/- 0.2 mg/dl). To further clarify whether the increased pressor response to vasoconstrictors may be due to the calcemic or direct action of active vitamin D3, we studied the effect of its noncalcemic analogue, 22-oxacalcitriol, and its inactive analogue, 24,25-dihydroxyvitamin D3, on the pressor response to vasoconstrictors in rats. The pressor responses to norepinephrine and Ang II were apparently augmented in 22-oxacalcitriol-treated rats similarly to 1,25-dihydroxyvitamin D3-treated rats. In contrast, the pressor responses were not affected by either 24,25-dihydroxyvitamin D3 or the intravenous infusion of calcium chloride. In an ex vivo experiment using a mesenteric preparation, the vascular sensitivity to norepinephrine was moderately augmented in rats treated with both 22-oxacalcitriol and 1,25-dihydroxyvitamin D3 but was not affected in rats treated with 24,25-dihydroxyvitamin D3. The results suggest that the enhanced pressor responses to norepinephrine and Ang II could be attributed to the direct effect of active vitamin D3 on vasculature rather than to hypercalcemia.

Differential induction of prostaglandin E2-dependent and -independent immune suppressor cells by tumor-derived GM-CSF and M-CSF

Both prostaglandin E2 (PGE2)-dependent (indomethacin-sensitive) and PGE2-independent (indomethacin-insensitive) suppressor cell activities that inhibited mitogenic T cell blastogenesis appeared in the bone marrow and spleen of mice on days 20 to 30 following transplantation of NFSA fibrosarcoma molecularly expressing mRNA for both macrophage (M) and granulocyte-macrophage (GM) colony-stimulating factors (CSFs). The present study was done to characterize the two different suppressor cells isolated from NFSA tumor-bearing mice and to verify a role of CSFs in the induction of suppressor cells in vitro. Whereas PGE2-releasing suppressor cells were found in bone marrow and spleen cells isolated from tumor-bearing mice, indomethacin-insensitive suppressor cells in both tissues were localized predominantly in adherent cell fractions. An increase in Mac-1+ and Mac-2+ spleen cell populations with two to three times larger cell volumes was observed, and both showed strong PGE2-releasing capacity and indomethacin-sensitive suppressor cell activity. However, after elimination of Mac-1+ or Mac-2+ cells, bone marrow cells still showed higher PGE2-releasing capacity and indomethacin-sensitive suppressor activity. The in vitro cultures of normal bone marrow and spleen cells with NFSA cell conditioned medium (NFSA-CM) induced heterogeneous mixtures of indomethacin-sensitive and - insensitive suppressor cells like those observed in cultures with the combination of M-CSF and GM-CSF. However, cultures with either GM-CSF or M-CSF resulted in the induction of indomethacin-sensitive suppressor cells by GM-CSF and of indomethacin-insensitive suppressor cells by M-CSF. In addition, NFSA-CM pretreated with anti-GM-CSF antibody induced indomethacin-insensitive suppressor cells in in vitro cultures of bone marrow and spleen cells. These results suggest that two distinctly different suppressor cells developed under hemopoiesis of myelomonocytic lineage cells are regulated differentially by the two macrophage growth factors, M-CSF and GM-CSF.

Study on the suppressive effect of iodine-enriched egg on LT-C4 production in arachidonic acid-induced ear inflammation

The anti-inflammatory mechanism of iodine-enriched egg was investigated in mice by means of arachidonic acid-induced ear inflammation. The lipid fraction of iodine-enriched egg was capable of suppressing the increase in ear weight induced by arachidonic acid in a dose-dependent manner. The lipid fraction was further separated into neutral and polar lipid fractions. Of these two fractions, only the neutral lipid fraction was capable of suppressing LT-C4 production in arachidonic acid inflammation. Neither the neutral nor polar lipid fractions of ordinary egg, however, showed any anti-inflammatory effect. These results suggest that the anti-inflammatory activity of iodine-enriched egg is present in the neutral lipid fraction, and its mechanism is assumed to be inhibition of LT-C4 production.

Differential alterations of dihydrofolate reductase gene in human leukemia cell lines made resistant to various folate analogues

In order to clarify a molecular mechanism of folate resistance in leukemia cells, we studied alterations of the dihydrofolate reductase (DHFR) gene in a human leukemia cell line, MOLT-3, and its sublines made resistant to methotrexate (MTX), trimetrexate (TMQ) and N10-propargyl-5,8-dideazafolic acid (CB3717), alone or in combination. Major alterations of the DHFR gene were examined by Southern analysis of high-molecular-weight DNA. The presence of a base change (T-->C) at nucleotide position 91 of the DHFR gene, which is reported to be responsible for the reduced affinity of the enzyme for MTX in an MTX-resistant human colon carcinoma cell, was examined by allele-specific oligonucleotide hybridization. In a 10,000-fold MTX-resistant subline (MOLT-3/MTX10,000), the normal allele of DHFR gene had been amplified. In contrast, a 200-fold TMQ-resistant subline (MOLT-3/TMQ200) and a 30-fold CB3717-resistant subline selected from MOLT-3/TMQ200 (MOLT-3/TMQ200-CB-3717(30)) were shown to have the mutant allele. Furthermore, the mutant allele had been amplified in a 500-fold MTX-resistant subline, which was established by the continuous exposure of the MOLT-3/TMQ200 cells to stepwise increases of drug concentration and designated as MOLT-3/TMQ200-MTX500. On the other hand, a 40-fold-resistant subline to CB3717 alone (MOLT-3/CB3717(40)) showed the normal allele without amplification. These data suggest that complex alterations of the DHFR gene are involved in the molecular mechanisms of folate resistance that can be differentially introduced into leukemia cells by exposure to various folate analogues, alone or in combination.

Detection of endothelin 1,2 and endothelin-like immunoreactant in wound surface and plasma in mice with thermal injury

Endothelin is a well known vasoconstrictive peptides produced by endothelial cells and has been reported to regulate the systemic circulation. The authors investigated changes in endothelin in plasma and the surface of wounds induced with thermal injury using an experimental ear burn model in mice. At 0, 15, 30, 60, 120 and 180 minutes after thermal injury the plasma endothelin-like immunoreactant levels were 1.50 +/- 0.21, 1.86 +/- 0.36, 2.81 +/- 0.55, 2.62 +/- 0.27, 1.54 +/- 0.14 and 1.25 +/- 0.19 fmol/ml (N = 8), respectively. Endothelin-like immunoreactant levels in the plasma increased gradually until 30 minutes after the thermal injury. Endothelin-like immunoreactant content in the ear before thermal injury and at 60 minutes after injury were 7.04 +/- 0.64 and 8.61 +/- 1.24 fmol/ear (N = 8), respectively. The change in endothelin-like immunoreactant after thermal injury originated from endothelin 1,2; that is, the endothelin-1,2 content of the burned ear increased significantly 15 and 60 minutes after thermal injury to 12.52 +/- 0.68 and 11.58 +/- 1.04 fmol/ear, respectively, compared with 1.78 +/- 0.91 fmol/ear (N = 8) obtained before injury. These results suggested that endothelin 1,2 existed in the region of the wound caused by thermal injury.

[The role of fibronectin in repairing fetal membrane]

The fibrin adhesion technique is being recognized as a way to prevent amniotic fluid leakage in the case of preterm premature rupture of the fetal membrane (PROM). However, the effect of fibrin adhesion is still not clear. The aim of this study is to investigate the implications of fibronectin in repairing the fetal membrane. We divided 9 normal fetal membranes into 4 groups. In all the groups, an incision was made in the membrane with a sterile knife. Group A: The incisions in the membranes were sealed with fibrinogen and thrombin (N = 9). Group B: The incisions in the membranes were sealed with fibrinogen and thrombin with fibronectin (N = 9). Group C: Fibronectin was added to the culture medium containing fetal membranes (N = 9). Group D: The fetal membranes were cultured in the medium alone (N = 9). All membranes were cultured for 6 days in 10% fcs added to MEM and analyzed histologically. In group A, fibrin clots did not attach to the membranes at all. In group B, fibrin clots attached closely to the membranes. In group C, fibroblasts increased remarkably at the incision sites on the fetal membranes. In group D, fibronectin accumulated at the incision sites on the fetal membranes. These results suggest that fibronectin is important in repairing fetal membrane.

[MR imaging of bone metastasis]

One hundred and three patients with known malignancy and suspected bone metastasis underwent magnetic resonance imaging. In 93%, the metastatic lesions, detected both on plain films and radionuclide bone scans, showed decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. All lesions, except one lesion showing much blastic change on plain films, showed contrast enhancement with Gd-DTPA administration. Although further investigation is needed, a correlation between the type of primary malignancy and the signal intensity of the metastatic lesion is suggested. Among 312 metastatic lesions detected by MR imaging, 272 lesions (87%) and 134 lesions (40%) were also detected by radionuclide bone scans and plain films, respectively. In five cases, MR imaging clearly revealed the lesion compressing the spinal cord, which helped us formulate a therapeutic plan. We conclude that MR imaging is the most sensitive examination for detecting bone metastasis and is necessary for planning treatment.