Intestinal anaerobic bacteria hydrolyse sorivudine, producing the high blood concentration of 5-(E)-(2-bromovinyl)uracil that increases the level and toxicity of 5-fluorouracil

Sorivudine, 1-beta-D-arabinofuranosyl-5-(E)-(2-bromovinyl)uracil, is a potent antiviral agent against varicella-zoster virus and herpes simplex virus type 1. However, sorivudine should not be used in combination with anticancer drugs such as 5-fluorouracil (5-FU) because (E)-5-(2-bromovinyl)uracil (BVU), a metabolite of sorivudine, inhibits the degradation of 5-FU, resulting in its accumulation in the blood and marked enhancement of the toxicity of 5-FU. Since phosphorolytic enzymes generate BVU from sorivudine, we investigated the distribution of the enzyme activity in rats. High activity was found in the cecal and large intestinal contents, while very low or no detectable activity in the liver, kidney, stomach, cecum, large intestine, and the stomach and small intestinal contents. These results suggest that intestinal microflora play an important role in BVU production. Therefore, we measured the phosphorylase activity in cell-free extracts from 23 aerobes, 16 anaerobes and a fungus. Bacteroides species B. vulgatus, B. thetaiotaomicron, B. fragilis, B. uniformis and B. eggerthii, dominant members of intestinal microflora, had high activity to convert sorivudine to BVU. To elucidate the contribution of intestinal microflora to BVU production in vivo, we administered sorivudine to rats treated with several antibiotics and measured the BVU concentration in the serum of rats. When sorivudine was given to rats treated with ampicillin or a mixture of bacitracin, neomycin and streptomycin, which decreased the numbers of viable aerobes and anaerobes, only a small amount of BVU was found in the serum. BVU concentration in the serum of rats treated with metronidazole to decrease the number of intestinal anaerobes was also very low. In contrast, BVU concentration in the serum of rats treated with kanamycin, which was used to decrease the number of aerobes selectively, was higher than that of non-treated rats. These results also suggest that BVU is produced by intestinal anaerobic bacteria especially Bacteroides species in vivo.

Murine P-glycoprotein on stromal vessels mediates multidrug resistance in intracerebral human glioma xenografts

Human glioma usually shows intrinsic multidrug resistance because of the blood-brain barrier (BBB), in which membrane-associated P-glycoprotein (P-gp), encoded by the human multidrug resistance gene MDR1, plays a role. We studied drug sensitivity to vincristine (VCR), doxorubicin (DOX) and nimustine (ACNU) in both intracerebrally and subcutaneously xenotransplanted human glioma. We examined the levels of MDR1 and murine mdr3 gene expression in the xenografts by reverse transcriptase polymerase chain reaction and the localization of P-gp by immunohistochemistry. Six of seven subcutaneously transplanted xenografts (scX) were sensitive to the above three drugs. In contrast, all three intracerebrally transplanted human glioma xenografts (icX) were resistant to P-gp-mediated drugs VCR and DOX, but were sensitive to the non-P-gp-mediated drug ACNU. Neither icX nor scX showed any MDR1 expression. Intracerebrally transplanted human glioma xenografts showed an increased level of murine mdr3 gene expression, whereas scX showed only faint expression. The localization of P-gp was limited to the stromal vessels in icX by immunohistochemistry, whereas scX expressed no P-gp. Our findings suggest that the P-gp expressed on the stromal vessels in icX is a major contributing factor to multidrug resistance in human glioma in vivo.

In vitro effects of doxorubicin and mitomycin C on human Tenon's capsule fibroblasts

Doxorubicin is an antiproliferative agent, that also inhibits prolyl 4-hydroxylase in vitro. We evaluated the effects of doxorubicin and mitomycin C (MMC) on the proliferation of human Tenon's capsule fibroblasts and the secretion of type I collagen in these cells to explore the potential use of doxorubicin as an antifibrotic agent after glaucoma filtering surgery. Standard immunoassays were used to determine the concentrations of type I procollagen COOH-terminal peptide (PIP), laminin and vitronectin receptor in conditioned media and cell lysates in the presence or absence of doxorubicin or MMC. The mitotic activity and viability of these cells were also determined. Cellular ultrastructure was evaluated by transmission electron microscopy. Doxorubicin and MMC decreased the cellular viability, the mitotic activity, and the production of the peptides measured. The inhibition of PIP secretion into the culture medium was higher in doxorubicin-treated cultures than in MMC-treated cultures at the tested concentrations (5-100 microM). The decrease in PIP levels in cell lysates was less in doxorubicin-treated culture (25 microM) than in MMC-treated culture (25 microM), suggesting that procollagen synthesis and secretion might be attenuated by doxorubicin. Ultrastructural studies revealed increased numbers of lysosomes in the cytoplasm of doxorubicin-treated cells relative to MMC-treated cells. Doxorubicin and MMC reduced cell viability and inhibited the proliferation and synthesis of PIP, laminin, and vitronectin receptor peptide. Inhibitory effects of doxorubicin on PIP secretion were more potent than those of MMC. Doxorubicin may be useful for inhibiting the fibrotic response at the site of ocular filtering surgery.

Posterior capsule rupture by blunt ocular trauma

A patient with posterior lens capsule rupture caused by blunt trauma and in whom the anterior capsule and the remainder of the eyeball structure was intact had phacoemulsification and aspiration of the crystalline lens with implantation of a posterior chamber intraocular lens. Further rupture of the capsule was prevented by the fibrosis, which tightened the margin of the ruptured capsule. This case shows that blunt trauma can rupture the posterior lens capsule, leaving the anterior capsule intact.

Characterization of a liver metastatic variant of murine colon 26 carcinoma cells

Intraportal vein injection of highly metastatic L5 cells consistently resulted in liver metastases (increases in the number of tumor colonies in the liver), whereas inoculation of P cells rarely did. L5 cells invaded the basement membrane Matrigel in greater numbers than did P cells, suggesting that the metastatic potential of L5 cells is partly related to enhanced invasive properties. The enhanced adhesion of L5 cells to fibronectin-, laminin- and Matrigel-coated substrates, as well as their haptotactic migration to fribronectin, may be associated with the preferential expression of VLA-2 and VLA-4 integrins on the surface of these cells detected by flow cytometry. Gelatin zymograms showed that the degradative activity of 72-kD gelatinases was greater in L5 cells than P cells. These results indicate that, in addition to adhesiveness and motility, the invasive ability of L5 cells may also be attributed to enhanced gelatinolytic activity. L5 cells grew more rapidly than P cells in vitro. Thus, an experimental model using highly metastatic colon 26 L5 cells would be useful for analyzing the molecular mechanism of liver metastasis and for evaluating the efficacy of treatment of occult micrometastases which may already have been disseminated at the time of surgery.

Successful treatment with ranimustine and carboplatin for recurrent intraocular retinoblastoma with vitreous seeding

This is the first report of successful treatment of recurrent retinoblastoma with vitreous seeding by a combination of ranimustine (MCNU) and carboplatin. The patient was diagnosed with bilateral retinoblastoma at 3 years of age. Although he received photocoagulation and radiotherapy for the left eye after enucleation of the right eye, a recurrent tumor associated with vitreous seeding developed 6 years later. The child underwent chemotherapy with cyclophosphamide and nimustine hydrochloride (ACNU), and a transient decrease of tumor cells in the vitreous was seen. We then changed the chemotherapy regimen to MCNU (70 mg/m2/ day for 1 day) and carboplatin (400 mg/m2/day for 2 days). After five courses of this chemotherapy, the tumor in the vitreous completely disappeared. No recurrence has been observed for > 4 years. Side effects, including myelosuppression, general fatigue, and vomiting, were observed during the course of chemotherapy, but they were ameliorated with supportive therapy. Neither nephro- nor ototoxicity was observed. The patient has useful vision. These results warrant further study of this novel drug combination in patients with recurrent, or even primary, retinoblastoma.

P-glycoprotein-mediated acquired multidrug resistance of human lung cancer cells in vivo

We examined whether the increased expression of P-glycoprotein (P-gp) encoded by the human multidrug resistance gene MDR1 is related to the acquired multidrug resistance of lung cancer in vivo. We estimated the chemosensitivity of lung cancer xenografts (LC-6, adenocarcinoma; Lu-24, small-cell cancer) by calculation of relative tumour growth (T/C%, treated/control) in vivo, based on statistical significance determined by the Mann-Whitney U test (P < 0.01, one-sided). MDR1 gene expression levels were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) assay. P-gp production and P-gp localisation were examined by Western blotting and by immunohistochemical analysis respectively. LC-6 and Lu-24 were initially sensitive to both vincristine (VCR, 1.6 mg kg-1: LC-6, 45%; Lu-24, 39%) and doxorubicin (DOX, 12 mg kg-1: LC-6, 26%; Lu-24, 27%) in vivo. VCR-resistant variants (LC-6R, 66% and Lu-24R, 68%) selected with VCR (0.4 mg kg-1, x 9) significantly acquired cross-resistance to DOX (LC-6R, 55% and Lu-24R, 55% respectively). RT-PCR assay showed increased levels of MDR1 expression in LC-6R and Lu-24R with stable MDR1 expression levels. P-gp expression levels were elevated, and the percentage of P-gp-positive tumour cells increased in both LC-6R and Lu-24R. These results suggest that P-gp/MDR1 overexpression is related to acquired multidrug resistance in lung cancer in vivo.

Collagen synthesis in lens epithelial cells on capsules containing intraocular lens implants in rabbits: immunolocalization of prolyl 4-hydroxylase

BACKGROUND

We evaluated ultrastructurally the presence and distribution of lens epithelial cells and extracellular matrix on the posterior capsule after implantation of a silicone or a polymethyl-methacrylate (PMMA) intraocular lens (IOL) in rabbits. The immunolocalization of prolyl 4-hydroxylase, an enzyme involved in procollagen synthesis, was also examined in such cells.

METHODS

Anesthetized adult albino rabbits (n = 12) underwent phacoemulsification and aspiration (PEA) of the crystalline lens and implantation of a silicone or a PMMA IOL into the capsular bag of one eye. They were killed by an intravenous overdose of pentobarbital sodium. The lens capsules were processed for transmission electron microscopy and for immunohistochemical detection of the beta-subunit of prolyl 4-hydroxylase.

RESULTS

Ultrastructurally, lens epithelial cells on the posterior capsule evidenced an accumulation of collagenous extracellular matrix. Prolyl 4-hydroxylase immunoreactivity was detected in the cytoplasm of cells distributed on the capsules.

CONCLUSION

Lens epithelial cells are involved in the production of collagenous matrix on lens capsules after PEA and implantation of IOL, resulting in a fibrotic process of the lens capsule.

Characterization of newly established human myeloid leukemia cell line (KF-19) and its drug resistant sublines

A new human myeloid leukemia cell line, designated KF-19, and its drug resistant sublines have been established. The KF-19 cell line was established from the pericardial effusion of a patient with acute myeloid leukemia clinically resistant to chemotherapy and KF-19 cells were characterized by expression of myeloid markers and differentiation into neutrophil- and macrophage-like cells upon optimal stimulations. KF-19AraC, KF-19ADR and KF-19VCR were established as sublines resistant to cytosine arabinoside (AraC), adriamycin (ADR) and vincristine (VCR), respectively. Efflux of the corresponding drugs was documented in each cell line. Expression of the MDR1 gene and the P-glycoprotein was found only in KF-19ADR, which showed a cross resistance to anthracyclines and vinca alkaloids; this resistance was reversed by verapamil or cyclosporin A. KF-19VCR lacking MDR1 gene and P-glycoprotein expression showed only resistance to vinca alkaloids, which was partially reversed by verapamil and cyclosporin A. Unexpectedly, KF-19ADR and KF-19VCR displayed cross resistance to AraC, despite lack of alterations of deoxycytidine kinase (dCK) and deaminase (dA) activities. KF-19AraC showed an efflux of AraC as well as a decreased level of dCK, but not of dA. In addition, KF-19AraC showed cross resistance to VCR in the efflux assay. The cell lines reported herein will provide new aspects on the mechanisms of drug resistance in leukemic cells.

[Brain monitoring with near infrared spectroscopy during carotid endarterectomy]

We evaluated clinical efficacy of near infrared spectroscopy (NIR) as a monitoring system for cerebral oxygenation during anesthesia for carotid artery endarterectomy. NIR proved to be affected significantly by clamping of the external carotid artery. The present study suggests that this monitoring system may be useful for evaluation of cerebral blood flow following declamping of the internal carotid artery, although it has some limitations during clamping of the artery.

Extracellular production of a Serratia marcescens serine protease in Escherichia coli

The Serratia marcescens serine protease (SSP) is one of the extracellular enzymes secreted from this Gram-negative bacterium. When the ssp gene, which encodes a SSP precursor (preproSSP) composed of a typical NH2-terminal signal peptide, a mature enzyme domain, and a large COOH-terminal pro-region, is expressed in Escherichia coli, the mature protease is excreted through the outer membrane into the medium. The COOH-terminal pro-region, which is integrated into the outer membrane, provides the essential function for the export of the mature protein across the outer membrane. This is a very simple pathway, in contrast to the general secretory pathway exemplified by the secretion of a pullulanase from Klebsiella oxytoca, in which many separately encoded accessory proteins are required for the transport through the outer membrane. Moreover, the NH2-terminal region of 71 amino acid residues of the COOH-terminal pro-sequence plays an essential role, as an "intramolecular chaperone," in the folding of the mature enzyme in the medium. In addition to ssp, the S. marcescens strain contains two ssp homologues encoding proteins similar to SSP in amino acid sequence and size, but with no protease activity. Characterization of the homologue proteins and chimeric proteins between the homologues and SSP, all of which are produced in E. coli, has shown that they are membrane proteins that are localized in the outer membrane in the same manner as for SSP. By use of the COOH-terminal domain of SSP, pseudoazurin was exported to the cell surface of E. coli, which proves the usefulness of the SSP secretory system in the export of foreign proteins across the outer membrane.

Inhibitory effect of a traditional Chinese medicine, Juzen-taiho-to, on progressive growth of weakly malignant clone cells derived from murine fibrosarcoma

We have investigated the inhibitory effect of oral administration of Juzen-taiho-to, a Kampo (Chinese herbal) medicine, on progressive growth of a mouse fibrosarcoma. Spontaneously regressive QR-32 tumor cells were able to grow progressively in vivo when coimplanted s.c. with a foreign body, gelatin sponge, whereas QR-32 cells alone gradually grew for over 15 days after inoculation and thereafter regressed for up to 25 days. Oral administration of Juzen-taiho-to (40 mg/day/mouse) for 7 days after inoculation of QR-32 cells with gelatin sponge resulted in significant inhibition of tumor growth and prolongation of the survival of the tumor-bearing mice. This growth-inhibitory effect of Juzen-taiho-to observed on day 25 was dose-dependent over the dose range from 4 to 40 mg/day. Treatment with Juzen-taiho-to for 7 days before tumor inoculation with gelatin sponge also significantly suppressed tumor growth examined on day 25, as did the administration of bismuth subnitrate, which is well known to induce metallothionein, an antioxidant. On the other hand, inoculation of progressed tumor cells (QRsP) resulted in growth without gelatin sponge, leading to death in syngeneic mice. Administration of Juzen-taiho-to for 7 days after inoculation of QRsP cells resulted in a decrease of the tumor growth and prolongation of the survival of mice, but the effect was less than that on the growth of QR-32 regressor tumor after coimplantation with gelatin sponge. These results suggest that the inhibitory effect of Juzen-taiho-to is partly associated with prevention of gelatin sponge-elicited progressive growth, probably mediated by endogenous factors including antioxidant substances, in addition to the augmentation of host-mediated antitumor activity.

Effect of ginseng radix on GLUT2 protein content in mouse liver in normal and epinephrine-induced hyperglycemic mice

The oral administration of the water extract of Ginseng Radix (GR) to normal and epinephrine-induced hyperglycemic mice caused a significant decrease in the blood glucose level 4 h after its administration. The hepatic content of facilitative glucose transporter isoform 2, liver type glucose transporter (GLUT2) protein content from mouse liver significantly increased in the orally GR-treated normal and epinephrine-induced hyperglycemic mice compared to that in the controls. These results suggest that the hypoglycemic activity of GR is presumably due, at least in part, to the increment of GLUT2 protein content.

Tyrosine phosphorylation of 100-130 kDa proteins in lung cancer correlates with poor prognosis

To search for the signalling pathways in lung cancer relevant to its aggressive behaviour, we studied tyrosine phosphorylated proteins in lung cancer cell lines and surgical specimens. We found that the profiles of protein phosphorylation were closely matched among these cell lines and cancer tissues of different histological origins, and 100-130 kDa proteins were the major components of phosphorylated proteins. In surgical specimens, approximately half of the cases showed tyrosine phosphorylation of these proteins in a tumour-specific manner, and phosphorylation of these proteins showed good correlation with the survival length of patients after operation. By immunoprecipitation with specific antibodies, we found that p125FAK, p120 and beta-catenin were the major components of tyrosine-phosphorylated proteins in the surgical specimens. These results suggest that tyrosine phosphorylation of these proteins may play a role in tumour relapse and is available as a clinical marker.

Sarcomatoid carcinoma of the small intestine: histologic, immunohistochemical and ultrastructural features of three cases and its differential diagnosis

Three cases of sarcomatoid carcinoma of the small intestine are presented. One of them was found accidentally in the duodenum of a patient with a well differentiated adenocarcinoma and a malignant lymphoma that were limited to the stomach. The other two cases arose from the ileum. All of the tumors were whitish, soft and ulcerated with focal hemorrhage and necrosis and showed expansive growth. Each tumor consisted of a mixture of polygonal and spindle shaped anaplastic neoplastic cells arranged in sheet, short fascicular or haphazard fashion, with no finding suggesting epithelial differentiation. Special stains demonstrated intracellular mucin in only a small number of tumor cells in two cases, but not in the other case. Immunohistochemically, the tumor cells of two cases at both primary and metastatic sites showed a positive immunoreaction for cytokeratin and epithelial membrane antigen. In the other case, only a few tumor cells at the metastatic site, but not at the primary site, showed cytokeratin positivity. Various numbers of tumor cells positive for vimentin, alpha-1-antitrypsin (AAT), alpha-1-antichymotrypsin (ACT) and KP-1 were detected in each case. Ultrastructurally, some populations of tumor cells possessed various amounts of tonofilaments with a few intercellular connections between adjacent tumor cells. These cases should be classified as sarcomatoid carcinoma of the small intestine, despite partial or complete loss of epithelial features, and distinguished from the various sarcomas.

[Electron microscopic observations on the posterior lens capsule after implantation of a silicone intraocular lens in rabbits]

We performed phacoemulsification and aspiration of the crystalline lens and implanted a silicone intraocular lens in the capsular bag in rabbits. The posterior capsules were then observed under transmission electron microscopy 2 or 4 months after the surgery. Lens epithelial cells proliferated between the posterior capsule and the optic portion of the silicone intraocular lens, accompanied with the accumulation of collagenous extracellular matrix.

Molecular cloning and nucleotide sequences of cDNAs encoding S-allele specific stylar RNases in a self-incompatible cultivar and its self-compatible mutant of Japanese pear, Pyrus pyrifolia Nakai

The genes encoding three RNases were cloned from the style of a self-incompatible cultivar, Nijisseiki (S2S4), and its self-compatible mutant, Osa-Nijisseiki (S2S4sm, sm means stylar part mutant), of Japanese pear. For Nijisseiki, cDNAs coding for two S-RNase (S2-RNase and S4-RNase) and an RNase unrelated to self-incompatibility (non-S-RNase) were cloned from the stylar cDNA library. The cDNAs coding for S2-RNase, S4-RNase, and non-S-RNase include 678-, 684-, and 681-bp open reading frames, respectively. Their deduced amino acid sequences were composed of signal peptides and mature RNases (201-203 residues) which were verified by partial amino acid sequencing. The primary structures of mature proteins revealed that these RNases are of the RNase T2 type; only the two S-RNases have several potential N-glycosylation sites and 60% of their amino acid residues are identical, compared with 25% sequence identity with the non-S-RNase. Such a distinct difference in the primary structures between S-RNases and non-S-RNase has not previously been reported and may be a feature typical of S-RNases in the family Rosaceae. Similar experiments were performed for Osa-Nijisseiki. The cDNAs coding for S2-RNase and non-S-RNase were similarly cloned from the stylar cDNA library. However, the cDNA coding for S4-RNase was neither amplified by PCR nor cloned from the library, suggesting that the mutation of self-incompatible Nijisseiki to self-compatible Osa-Nijisseiki is due to a failure of expression of S4-RNase. These results lead to the idea that Osa-Nijiisseiki is a variant of Nijisseiki in which the S4-allelic gene in the S-locus is exclusively mutated or deleted, causing severely impaired or suppressed expression of its gene product, S4-RNase, at the style.

Effect of fibrostatin C, an inhibitor of prolyl 4-hydroxylase, on collagen secretion by human Tenon's capsule fibroblasts in vitro

PURPOSE

To investigate the effect of fibrostatin C, a prolyl 4-hydroxylase (PH) inhibitor produced by Streptomyces catenulae subsp. griseospora, on type I collagen secretion by human Tenon's capsule fibroblasts (TCFs) in vitro, as an indication of the potential therapeutic efficacy of this compound in antifibrotic therapy after glaucoma filtering surgery.

METHODS

The concentrations of type II procollagen COOH-terminal peptide (PIP) in culture medium or cell lysate were determined by immunoassays. For comparison with its effect on PIP secretion, we determined the effects of the agent on the secretion of other peptides, including laminin, vitronectin receptor, and a metalloproteinase inhibitor. The expression of collagens I and III, fibronectin, and PH by TCFs was examined by immunohistochemistry, and cellular ultrastructure was evaluated by transmission electron microscopy.

RESULTS

Fibrostatin C (50 microM) significantly reduced the concentration of PIP in culture medium and increased its concentration in the cell lysate in a dose-dependent manner, but it had no effect on the secretion of other peptides. Cell viability and proliferation were not affected by fibrostatin C. Fibrostatin C also increased the number of cytoplasmic granules immunoreactive with antibodies to collagen I or III, but had no effect on fibronectin or PH immunoreactivity. Ultrastructurally, cisternae of the endoplasmic reticulum were dilated in fibrostatin C-treated TCFs, consistent with the retention of underhydroxylated collagen precursors in this organelle.

CONCLUSIONS

Fibrostatin C inhibits the secretion of type I collagen by cultured TCFs. This agent may thus prove therapeutically beneficial for inhibiting the excess fibrosis in the wound of filtering surgery.

[The efficacy of transesophageal echocardiography during the pericardial drainage of the cardiac tamponade after cardiac surgery]

For two cases of cardiac tamponade following cardiac surgery, the approaches for pericardial drainage were determined by the transesophageal echocardiography under general anesthesia. In most cases of cardiac tamponade after cardiac surgery the pericardial effusion is regional and localized due to adhesions of pericardium. Therefore subxiphoid incision approach of pericardial drainage cannot often be accomplished. In these cases transesophageal echocardiography can image the presence, location and size of the pericardial effusion and is an available method to determine the approach of pericardial drainage.

Expression of fos family and jun family proto-oncogenes during corneal epithelial wound healing

PURPOSE

While transformation of epithelial cells to a motile form is the first step in wound healing of the corneal epithelium, the migratory mechanism in these cells is not fully understood. We studied the expression of proto-oncogene mRNAs: c-fos; c-jun; fos B; jun B; jun D in injured corneal epithelium using in situ hybridization. Moreover, we examined immunolocalization of c-Fos and c-Jun protein products to elucidate the transcriptional activation prior to the onset of migration in corneal epithelium.

METHODS

An epithelial defect was made on one cornea of 60 Wistar rats. The affected eye was enucleated immediately (within 5 min) or was allowed to heal for 15, 30, 60, 90, 120 and 180 min. Frozen sections were processed for in situ hybridization with c-fos, c-jun, fos B, jun B and jun D mRNAs or were stained with anti-c-fos and anti-c-jun antibodies.

RESULTS

Fifteen min after the epithelial ablation, weak signals for c-fos and c-jun mRNAs were detected in the corneal epithelium surrounding the wound. These signals reached a peak 30 to 60 min after ablation, but were no longer evident at 120 min. Immunoreactivities for these proteins were also detected in the same area at 60 to 120 min after the epithelial ablation. Fos B mRNA was detected in the same region at 30 min after the ablation, and reached its peak after 30 to 60 min, but was no longer evident at 120 min. Jun B mRNA was detected in the epithelium around the defect 60 min after the ablation, later than the other proto-oncogenes, and reached its peak after 90 min. The message for jun D was detected in normal epithelium, and was not affected by wounding.

CONCLUSIONS

These findings indicate that transcriptional activation of epithelial cells is initiated in the early phase after epithelial ablation, before the cells start to migrate, and that these proto-oncogene products may play important roles in wound healing in corneal epithelium. The time lag of the peak of expression of these proto-oncogenes in this process.

In vivo formation of mutagens by intraperitoneal administration of polycyclic aromatic hydrocarbons in animals during exposure to nitrogen dioxide

Consumption of fossil fuels has increased indoor and outdoor concentrations of polycyclic aromatic hydrocarbons (PAHs) and nitrogen dioxide (NO2). To study the combined effect of PAH administration and NO2 exposure on mutagenicity of urine from animals we injected 400 mg/kg body wt i.p. one of five kinds of PAH (pyrene, fluoranthene, fluorene, anthracene and chrysene) into ICR mice, Wistar rats, Syrian golden hamsters or Hartley guinea pigs after exposure to 20 p.p.m. NO2 gas for 24 h and then exposed the animals to NO2 gas for an additional 24 h. During the latter 24 h we collected the urine and assayed its mutagenicity with the Ames Salmonella strains after treatment with beta-glucuronidase and arylsulfatase and extraction with dichloromethane. The urine from mice treated with both PAH and NO2 showed high mutagenicity for Salmonella typhimurium strains TA98 and TA100, whereas the urine from mice treated with PAH and air showed almost no mutagenic activity. The mutagenicity was decreased in nitroreductase- and acetyltransferase-deficient strains TA98NR and TA98/1,8-DNP6 respectively. Treatment with a mixture of 20% of each of the five kinds of PAH and NO2 augmented the urinary mutagenicity of mice 1.5-fold. The urine from hamsters treated with pyrene or fluoranthene and NO2 was also highly mutagenic, but that from rats or guinea pigs was not very mutagenic. The mutagenicity was also decreased in strains TA98NR and TA98/1,8-DNP6. These results suggest that the urine contains nitro compounds and that the nitration of PAHs occurs in the body of animals under exposure to NO2 gas. Actually, the nitrated metabolites of pyrene, 1-nitro-6/8-hydroxypyrene and 1-nitro-3-hydroxypyrene, were detected in the urine from mice treated with pyrene under exposure to NO2 gas. To elucidate the mechanism of in vivo nitration, NO2 (20 p.p.m.) was bubbled through 50 mM Tris-HCl buffer (pH 7.4) or dichloromethane solution containing pyrene or 1-hydroxypyrene (10 microg/ml). Pyrene was not nitrated by NO2 in either aqueous or organic solutions. However, 1-hydroxypyrene was changed to nitrohydroxypyrenes by NO2 in the Tris-HCl buffer, but not in the organic solution. Ascorbic acid, alpha-tocopherol, glutathione oleic acid and hemoglobin were found to inhibit the nitration of 1-hydroxypyrene in aqueous solution. The urinary mutagenicity of mice treated with both pyrene and NO2 was also decreased by oral administration of ascorbic acid and alpha-tocopherol. These results suggest that 1-hydroxypyrene is nitrated by an ionic reaction in the animal body after hydroxylation of pyrene in the liver.

[Automated analysis of all-night records of tracheal sound to detect sleep disordered breathing]

In sleep-disordered breathing, tracheal sounds disappear during apnea and vary cyclicly during hypopnea. We tried to detect these changes in tracheal sounds automatically with a personal computer, and we evaluated the diagnostic accuracy of this system for detecting sleep-disordered breathing. Polysomnography and tracheal sound recording were done in 33 subjects with possible sleep apnea/hypopnea syndrome. Eighteen had positive results defined as an apnea/hypopnea index greater than 15. Tracheal sounds were digitized and a personal computer was used to calculate short time power spectra (44-600 Hz) every 0.2 seconds by the fast Fourier transform. The moving averages (18 seconds) of the logarithms of the power spectra were calculated every 2 seconds. Transient falls in the moving averages of more than 12 dB were detected. Those that were lower than 5 dB above the level of background noise were classified as tracheal sound apneas. The number of falls of more than 12 dB and the number of tracheal sound apneas correlated strongly with the number of apneas plus hypopneas (r = 0.95) and with the number of apneas (r = 0.97), respectively. The sensitivity and specificity of tracheal sound analysis for the sleep apnea/hypopnea syndrome (as defined above) were 89% and 60%, respectively, when the criteria was more than 15 falls of more than 12 dB per hour. We conclude that tracheal sound analysis by this method is useful as a screening test for the sleep apnea/hypopnea syndrome.

In vitro and in vivo anti-tumour effects of a humanised monoclonal antibody against c-erbB-2 product

The c-erbB-2 product is thought to be a unique and useful target for antibody therapy of cancers overexpressing the c-erbB-2 gene. In vitro and in vivo anti-tumour effects of a humanised antibody against the extracellular domain of the c-erbB-2 gene product, rhu4D5, were examined. Rhu4D5 was less effective than its murine counterpart, mu4D5, for the direct antiproliferative activity against the c-erbB-2-overexpressing SK-BR-3 cell line. In vivo treatment of severe combined immunodeficient (SCID) mice carrying the c-erbB-2-overexpressing 4-1ST human gastric carcinoma xenograft with 4hu4D5 revealed that the recombinant protein had potent anti-tumour activity. Furthermore, cytotoxicity of human peripheral blood mononuclear cells against 4-1ST was significantly augmented with rhu4D5, but not with mu4D5. These results indicate that rhu4D5 might perform better in patients than predicted from preclinical studies.