Cerebral vasodilatory effect of high-dose, intravascular endothelin-1: inhibition by NG-monomethyl-L-arginine

The effects of intracarotid administration of endothelin-1 on the cerebral microvessels were examined in anesthetized cats. The local cerebral blood volume in the cortex, which reflects the cumulative dimensions of the cerebral microvessels, was measured by our photoelectric method. A low dose of endothelin-1 (0.1 nmol) elicited mild but significant declines in cerebral blood volume. Following a high dose of endothelin-1 (3 nmol), the cerebral blood volume was initially reduced, probably due to the marked fall in arterial blood pressure, but was subsequently increased significantly. The increase in cerebral blood volume was not secondary to the rise in blood pressure, since it was unaffected by inhibition of the blood pressure changes with BQ-123 (1 mg/kg), an endothelin antagonist. However, the cerebral blood volume increase was prevented by continuous administration of NG-monomethyl-L-arginine (0.35 mg/kg per min), an inhibitor of nitric oxide synthesis, plus BQ-123. BQ-123 itself had no significant effects on cerebral blood volume or blood pressure. We conclude that while a low dose of intravascular endothelin-1 steadily constricts the cerebral microvessels, a high dose dilates the cerebral microvessels through the induction of nitric oxide synthesis, probably in the endothelium.

Spinal cord potential recordings from the extradural space during scoliosis surgery

For monitoring spinal cord functions during corrective surgery of scoliosis, we have recorded percutaneously from the posterior extradural space at the C5-7 levels the ascending conducted spinal cord potentials (ASCP) in response to extradural stimulation of the cauda equina in 134 patients. The ASCP consists of three spike-like components (C1, C2 and C3) followed by slow components. The extradurally recorded ASCP were not affected by anaesthetic agents. There were no significant differential effects of spinal distractions on each of the three spike potentials. There were no post-operative neurological abnormalities in patients whose ASCP showed no changes, amplitude increases, amplitude decreases of less than 50% or latency increases (> 0.2 ms) during spinal manipulations (no false negatives, but some false positives). Five patients who suffered postoperative neurological damage exhibited more than 50% changes in amplitude of the ASCP during surgery. All these neurological sequelae occurred in the first 80 patients. In the last 54 patients, in whom the distraction forces on the spine were controlled rapidly by observation of the amplitude changes in ASCP, there were no postoperative neurological abnormalities, except for one patient in whom an accidental spinal cord injury was produced by a hook. The results suggest that the distraction force on the spine must be reduced immediately when the amplitudes of the ASCP decrease by more than 50% of control values with or without latency increases.

Dilatation of cerebral microvessels mediated by endothelin ETB receptor and nitric oxide in cats

The functional role of the endothelin (ET)B receptor in the cerebral microvessels was examined in seven anesthetized cats. The effects of intracarotidly injected IRL1620, a selective ETB receptor agonist, on the cerebral blood volume (CBV) in the cortex were examined by a photoelectric method. CBV reflects the cumulative dimensions of the cerebral microvessels. High doses of IRL1620 (0.1-1 nmol/kg) elicited a transient fall in CBV, followed by a marked and dose-related increase of CBV (P < 0.01). The CBV increase was significantly inhibited (P < 0.01) by simultaneous administration of 0.35 mg/kg/min NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthesis. The marked, but transient, depressor effect of IRL1620 was also attenuated (P < 0.01) by L-NMMA. The ETB receptor subtype and production of nitric oxide, probably in the endothelium, mediate the vasodilatory action of ET in the cerebral microvessels.

Immunohistochemical phenotyping of liver macrophages in normal and diseased human liver

The phenotypical heterogeneity of human liver macrophages was analyzed with monoclonal antibodies that recognize antigens specific for the monocyte-macrophage lineage. Most liver macrophages in normal and diseased liver were positive for CD68, whereas fewer matured macrophages were detected by 25-F9. Comparative staining of mirror sections revealed some to be doubly positive and others to be singly CD68 positive. Quantitative analysis confirmed the difference, suggesting heterogeneity of maturation in liver macrophages. Most liver macrophages in the normal liver were negative for CD14, a receptor for lipopolysaccharide and lipopolysaccharide-binding protein complexes. Liver macrophages in liver diseases were activated to express CD14 at varying degrees and were involved in the clearance of lipopolysaccharide-lipopolysaccharide-binding protein complexes. Fc gamma RI, a receptor for monomeric IgG that is involved in antibody-mediated cell cytotoxicity, was negative in the normal liver, but was expressed in liver macrophages at inflammatory sites (e.g., in piecemeal and focal necrosis) in diseased livers. Fc gamma RII was expressed in most liver macrophages, as well as in sinusoidal endothelial cells; Fc gamma RIII was expressed in a smaller number of liver macrophages. Expression of Fc gamma RII and Fc gamma RIII was increased in chronic active hepatitis. These results suggest that liver macrophages are heterogeneous in maturation and function and that they are activated in liver diseases as shown by the novel expression of CD14 and Fc gamma RI. The restricted expression of Fc gamma RI indicates that Fc gamma RI-positive macrophages, in cooperation with cytotoxic T lymphocytes, may play an important role in liver cell injury through antibody-mediated cell cytotoxicity.

Monitoring canine lung allograft rejection using Ia antigen expression by bronchoalveolar lymphocytes

The expression of Ia antigens by lymphocytes in bronchoalveolar lavage (BAL) was evaluated after canine lung allotransplantation with immunosuppression using FK-506. The expression of Ia antigens labeled using an OKIa-1 monoclonal antibody from Ortho Diagnostic Systems was measured by flow cytometry. Twenty-three adult mongrel dogs underwent left lung allotransplantation and were treated with FK-506 at a dose of 0.1 mg/kg/day intramuscularly until death. Allograft rejection was evaluated microscopically. The percentage of OKIa-1-positive cells among the BAL lymphocytes was 34.8% +/- 8.9% (mean +/- SD) from the allografted lungs showing no rejection, whereas it was 68.8% +/- 16.2% from the allografted lungs which showed rejection (P < 0.01). When a diagnosis of rejection was made prior to pathologic examination by an OKIa-1-positive lymphocyte percentage of 42% or more, the sensitivity, specificity, and accuracy of diagnosis were 100%, 87.5%, and 94.1%, respectively. Subsequently, pulse steroid therapy was attempted in those dogs with a high rate of OKIa-1-positive lymphocytes in the BAL. In 3 of 4 dogs showing histological signs of rejection, a decrease in the rate of OKIa-1-positive cells among the BAL lymphocytes corresponded to an improvement in pathologic diagnosis. In two dogs with bacterial pneumonia and pulmonary vein thrombosis, densities indistinguishable from those of rejection were seen on chest roentgenograms, but in these dogs the rate of OKIa-1-positive BAL lymphocytes was 42% or less. In conclusion, Ia antigen expression by BAL lymphocytes could be useful for monitoring rejection in lung allotransplantation.

[Bilateral bronchioloalveolar carcinoma, showing familial aggregation of lung cancer]

Bilateral bronchioloalveolar carcinoma in a 56-year-old female is reported. In June 1992, an abnormal shadow was noted on chest X-ray during mass screening. Sputum cytology revealed class V, adenocarcinoma. Mass shadow in both lower lobes were found on chest computed tomography. Simultaneous bilateral thoracotomy was performed by submammary transverse skin incision at the level of the fourth intercostal space. Right lower lobectomy and left S9 partial resection were performed. Bronchioloalveolar carcinoma was confirmed by microscopic findings in both specimens. Four of seven siblings had lung cancer and one had simultaneous renal cell carcinoma. Furthermore, the patient's father, two maternal uncles, one cousin and one nephew also had lung cancer. Two of the brothers and the nephew with lung cancer were confirmed to have well differentiated adenocarcinoma by pathological examination.

Quantitation of the hydroxyl radical adducts of salicylic acid by micellar electrokinetic capillary chromatography: oxidizing species formed by a Fenton reaction

There has been controversy concerning the products formed by a Fenton reaction. We determined the hydroxyl radical (.OH) generated in a Fenton reaction system with no iron chelator using micellar electrokinetic capillary chromatography (MECC). The hydroxyl radical generated in this Fenton system attacked salicylic acid to produce major products of 2,3- and 2,5-dihydroxybenzoic acid (DHB), 2,3-DHB being prominent. Hydroxyl radical scavengers, such as mannitol, ethanol, thiourea and a ferric chelator, Desferal, significantly diminished the peaks for DHBs, showing production of .OH. We compared the MECC method with the electron paramagnetic resonance (EPR) spin trapping technique. The quantity of DHBs obtained by MECC increased dose-dependently up to 1 microM Fe2+ at a fixed concentration of H2O2, whereas that of the spin adduct by EPR showed a bell-shaped curve. This quantitation of .OH adducts by MECC supports the proposal that the oxidizing species formed by a Fenton reaction with no chelator is .OH. The EPR spin trapping method appears to be erroneous, particularly when iron is present at a higher concentration than hydrogen peroxide. The application of this method to the paraquat effect in vitro is demonstrated, and the possibility for analysis of .OH in vivo is also discussed.

[Clinical evaluation of dynamic MRI in the re-diagnosis of therapeutic effect and recurrence after transcatheter arterial embolization for hepatocellular carcinoma]

We evaluated re-diagnostic ability of dynamic MRI as compared with T2 weighted image in the diagnosis of primary therapeutic effect and tumor recurrence after transcatheter arterial embolization (TAE) for hepatocellular carcinoma. Thirty-four nodules in 30 patients with hepatocellular carcinoma were estimated based on operative and angiographic findings. According to the time when dynamic MRI was taken, nodules were classified as a short-term observation group consisting of 15 nodules obtained within a month after TAE, or as a long-term observation group consisting of 19 nodules obtained over a month after TAE. In the short-term observation group, sensitivity, specificity, accuracy was 89%, 100%, 93% on dynamic MRI and 78%, 67%, 73% on T2WI, respectively. In the long-term observation group, these were 94%, 100%, 95% on dynamic MRI and 100%, 33%, 89% on T2WI and 94%, 67%, 89% on Lipiodol-CT, respectively. In both groups, dynamic MRI was superior in accuracy. Conclusively, we consider that dynamic MRI is a most accurate diagnostic method that should be added to routine MRI after TAE. Especially in the case diagnosed positive on T2WI, the usefulness of dynamic MRI should be emphasized to determine the schedule of the therapy, because the cases that were false positive on T2WI were accurately diagnosed on dynamic MRI.

[Segmentectomy and bronchoplasty for early stage squamous cell carcinoma of the segmental bronchus]

Five cases with hilar type early stage squamous cell carcinoma of the segmental bronchi underwent segmentectomy and bronchoplasty. All were males and the ages with sixties. Locations of early stage lung cancer were the apical bronchus of the right lower lobe (B6) in one patient, the intermediate-lower lobe bronchus in one, the anterior bronchus of the left upper lobe (B3) in two and the lower division bronchus (B4+5) in one. All were diagnosed as early stage squamous cell carcinoma by preoperative bronchoscopic examination. The segments resected were the right S6 in two, left S1+2+3 in one, left S4+5 in one and left S3 in one. There was no postoperative complications related to bronchial anastomosis. One patient died of secondary primary lung cancer 3 years after operation. While, four patients are alive and well one, 6, 12 and 46 months after surgery. Sleeve segmentectomy for the patients with early stage squamous cell carcinoma of the segmental bronchus is a curative operation with preserving pulmonary function.

Specific PCR amplification for N-ras mutations in neoplastic thyroid diseases

We analyzed point mutations of N-ras protooncogene codon 61 in thyroid neoplasms by means of a mutation-specific PCR method. In this method, one of the paired primers has a base at the 3' terminal that is complementary to a mutated base of the DNA sequence to be analyzed. With this primer, only alleles which have the same mutation can be amplified. Among 24 thyroid tissues, we detected 2 point mutations out of 7 follicular carcinomas (29%). One tumor had a cytosine to adenine substitution mutation at the first base of codon 61, and the other had an adenine to guanine substitution mutation in the second base of the same codon. The same mutations were not detected in 7 follicular adenomas or 1 papillary carcinoma. These results were confirmed by both dot blot hybridization and direct sequencing method. Mutation of N-ras codon 61 may be significant in malignant transformation of follicular thyroid tumors. Because of its easy availability, the mutation-specific PCR method is a useful screening test for N-ras mutations.

Nonsuppurative cholangitis is induced in neonatally thymectomized mice: a possible animal model for primary biliary cirrhosis

Neonatally thymectomized mice are unique in that they are prone to organ-specific autoimmune diseases. We investigated whether autoimmune cholangitis could be induced in these mice when they were immunized with biliary antigens. Neonatally thymectomized A/J mice were immunized with porcine intrahepatic bile duct epithelial cells (group 1), porcine gallbladder epithelial cells (group 2), porcine splenocytes (group 3) or Freund's adjuvant (group 4). Nonthymectomized mice were immunized with bile duct epithelial cells (group 5) or Freund's adjuvant (group 6). The cell suspensions were injected intraperitoneally with Freund's adjuvant once a week for 8 wk. In group 1 varying amounts of mononuclear cells infiltrated around the bile duct in 14 of 22 mice, whereas little or no accumulation was noted in other groups. Ultrastructural observations revealed that the inflammatory cells consisted of lymphocytes, plasma cells and macrophages. The bile duct showed degenerative changes and some lymphocytes infiltrated between bile duct epithelial cells. An immunohistochemical study showed that the accumulated lymphocytes consisted of CD4+ and CD8+ T cells, as well as B cells. Both major histocompatibility complex class I and class II antigens were expressed on bile duct epithelial cells. Antimitochondrial antibody was demonstrated in some mice in groups 1 (9 of 17), 2 (2 of 3) and 5 (4 of 5) by immunofluorescence; the antibody reacted with the 68, 52 and 47 kD polypeptides of the pyruvate dehydrogenase complex on Western blotting. These findings suggest that autoimmune cholangitis can be induced in neonatally thymectomized mice stimulated with biliary antigens and that these mice could be a suitable animal model for primary biliary cirrhosis.

Receptor-mediated endocytosis of chemically modified albumins by sinusoidal endothelial cells and Kupffer cells in rat and human liver

Human serum albumin (HSA), formaldehyde-treated HSA (FHSA), and HSA polymerized with glutaraldehyde (pHSA) were conjugated with colloidal gold (15 (15G) or 50 (50G) nm in diameter). The labeled proteins were injected into the portal veins of rats and followed by electron microscopy. Both 15G-FHSA and 15G-pHSA were taken up by sinusoidal endothelial cells (Ec) and Kupffer cells (Kc). Five minutes after injection, gold particles were observed on the surface of Ec and Kc. At 10 min, most gold particles were gathered in the coated pits and vesicles of Ec. In Kc, gold particles were observed in both coated vesicles and macropinocytotic vesicles. At 15 min, the gold particles were localized mainly in the endosomes and some lysosomes of Ec and in the large vacuoles of Kc. At 30 min, the gold particles had been gathered into the secondary lysosomes and condensed. At 60 min, some gold particles were observed in the cytoplasm of Ec. The fate of 15G-pHSA was the same as that of 15G-FHSA. Simultaneous injection of 15G-pHSA and 50G-FHSA revealed that particles of both sizes were taken up together into the coated pits and vesicles of Ec. Preperfusion of livers with unlabeled FHSA, pHSA, or formaldehyde-treated bovine serum albumin (FBSA) inhibited the uptake of 15G-FHSA or 15G-pHSA by Ec. In a human liver biopsy specimen, both 15G-FHSA and 15G-pHSA were taken up by Ec and Kc through coated vesicles, as in the rat liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of anastomotic complications after sleeve lobectomy for lung cancer

One hundred twelve patients (102 male and 10 female) underwent sleeve lobectomy for lung cancer from January 1969 to December 1991. Bronchopleural fistula occurred in 6 (5.6%), bronchovascular fistula in 2 (1.8%), pulmonary arterial occlusion in 2 (1.9%), anastomotic stricture or stenosis in 7 (6.3%), and local recurrence in 7 patients (6.3%). Early repair of bronchopleural fistula combined with an omentopexy achieved permanent closure of the fistula. Two patients who underwent a completion pneumonectomy for a pulmonary arterial occlusion died of respiratory failure. Two patients experienced uncontrollable bleeding into the bronchial tree through a bronchovascular fistula and sudden death. Completion pneumonectomy is indicated for a stricture due to scar formation. If pneumonectomy is precluded by poor pulmonary reserve, endoscopic excision using biopsy forceps is an alternative. Endoscopic resection is the treatment of choice for suture granulomas. Complications associated with bronchial or vascular anastomoses are serious and frequently fatal.

An immunohistochemical study of the distribution of blood group substances and related antigens in primary colorectal carcinomas and metastatic lymph node and liver lesions, using monoclonal antibodies against A, B, H type 2, Le(a), and Le(x) antigens

Using indirect immunoperoxidase staining, we examined the distribution of blood group substances and related antigens, including Le(a), A, B, H type 2, and Le(x), in 87 carcinomas and 42 normal mucosal specimens of colon and rectum, as well as in metastatic lesions of 32 lymph nodes and 9 liver specimens. The compatible expression rate of A/B/H type 2 antigens was 33.3% (3/9) in proximal normal colon, but only 6.1% (2/33) in distal normal colon. Compatible expression was observed in 14 of 25 carcinomas in the proximal colon (56.0%), but these antigens in distal colon cancers reappeared with a high positive rate, 62.9% (39/62). The rate of H type 2 accumulation with the deletion of A and/or B antigens was 6.9% (6/87). Incompatible expression was not observed in colorectal cancer. Le(a) and Le(x) antigens were expressed in normal mucosa and primary carcinoma throughout the colon. Le(a) and Le(x) in primary carcinoma that showed A/B deletion with/without H type 2 accumulation was expressed more than in carcinoma with A/B/H type 2 compatible expression (88.2% vs 71.7% for Le(a); 94.1% vs 88.7% for Le(x), respectively). In 16 of 32 patients (50.0%), A/B/H type 2 antigen expression in metastatic lesions had disappeared or was decreased compared with that in primary carcinoma, followed by metastasis to regional lymph nodes. These results suggested that: (a) A/B/H type 2 blood group substances in the distal colon behave as tumor-associated antigens in colorectal carcinoma. (b) Most frequently, A/B/H type 2 antigens expressed in primary carcinoma were weakened or had disappeared in metastatic lymph nodes. Further investigation of the biological function of carbohydrate chains, such as those of blood group substances and related antigens on cancer cell surfaces may lead to a solution of the problem of the metastatic behavior of tumor cells.

Structural study on the glycosyl-phosphatidylinositol anchor and the asparagine-linked sugar chain of a soluble form of CD59 in human urine

CD59 is an 18-kDa glycoprotein widely expressed on human cells. An important structural feature of CD59 is its attachment to the cell surface via a glycosyl-phosphatidylinositol (GPI) anchor. CD59, like many GPI-anchored proteins, has been found in urine, serum, and other body fluids. The structures of the GPI anchor and the asparagine-linked sugar chain of a soluble form of CD59 in urine, U-CD59, were determined. Purified U-CD59 released 1 mol of inositol per mole of protein by nitrous acid deamination, which cleaved between glucosamine and inositol present commonly in the GPI anchor. This indicates that a GPI anchor, which ended with inositol, is linked at the carboxy terminus of U-CD59. The peptide containing an asparagine-linked sugar chain and the peptide containing a glycan portion of the GPI anchor were isolated after trypsin digestion of U-CD59. The asparagine-linked sugar chains and the glycan portion of the GPI anchor were isolated from these peptides following hydrazinolysis or deamination and dephosphorylation, respectively. Their structures were analyzed by sequential exoglycosidase digestion and methylation analyses. The structures of the asparagine-linked sugar chains of U-CD59 were biantennary complex type, only 4.2% of which are monosialylated. The backbone structure of the GPI anchor was similar to that of Try-panosoma brucei variant surface glycoprotein, but showed significant variations in its side-chain moieties. This is the first detailed structural analysis of the human GPI anchor and the first detailed analysis of the carboxyl-terminal structure of the soluble-form GPI-anchored protein. The results indicate that the backbone structure of the GPI anchor is conserved from parasites to human and that at least a part of the soluble-form GPI-anchored protein has the structure produced by the action of glycan-phosphatidylinositol-specific phospholipase D.

Erb's point stimulation produces slow positive potentials in the human lumbar spinal cord

Evoked spinal cord potentials (SCPs) were recorded from the posterior epidural space (PES) at the cervical and lumbrosacral enlargements in response to electrical stimulation of the brachial plexus at Erb's point in 17 chronic pain patients. Erb's point stimulation produced slow positive potentials (heterosegmental slow positive potentials, HSPs) in the PES at the lumbrosacral enlargement in all 13 subjects without spinal cord lesions but not in 4 subjects with spinal cord lesions. The HSP1 with a central peak latency of 21 +/- 2 ms (mean +/- SE) was recorded at the stimulus intensity up to two to three times the threshold strength (T) of the initially positive spike (P1) of the segmental SCP, which was simultaneously recorded from the PES at the cervical enlargement. At the stimulus intensity of more than 3T, another slow positive potential (HSP2) with central peak latency of 71 +/- 6 ms was recorded. These slow positive potentials (HSP1 and HSP2) might be produced by a feedback loop via supraspinal structures, presumably primary afferent depolarizations, in comparison to the HSPs of our previous studies in the rat. Slow negative potentials were sometimes noted before (5 of 13) and/or after (2 of 13) the HSP1. These slow negative potentials probably reflect the activities of dorsal horn neurons producing the HSP1 and HSP2, respectively, also elicited by a feedback loop via supraspinal structures.

Comparison of absorption-enhancing effect between sodium caprate and disodium ethylenediaminetetraacetate in Caco-2 cells

The effects of sodium caprate (C10) and disodium ethylenediaminetetraacetate (EDTA) on the epithelial permeability of polyethylene glycol 4000 (PEG4000) were examined in Caco-2 cell monolayers on the polycarbonate membrane (filter) of a Transwell cluster dish. Under serosal Ca(2+)-free conditions irrespective of the presence or absence of mucosal Ca2+, the permeability of PEG4000 was remarkably enhanced, even in the absence of enhancer. For control experimental conditions with a permeation enhancer in Caco-2 cells, Ca2+ was added to both the mucosal and serosal sides. Under the control conditions, EDTA increased the permeability of PEG4000 to 14 times the control and C10 by 3.5 times. Mucosal Ca(2+)-free conditions further increased the EDTA-enhancing effect, to 29 times the control value. In contrast to the EDTA effect, however, the C10 effect was unchanged in the absence of mucosal Ca2+. These results suggest that the EDTA effect is induced by chelation with Ca2+ but that C10 has some other action in addition to chelation.

Recombinant soluble CD59 inhibits reactive haemolysis with complement

Three soluble forms of membrane attack complex inhibitory factor (MACIF or CD59) were prepared using recombinant baculovirus-infected insect cells. They consisted of 70, 77 and 86 amino acids, starting from the amino terminus of naturally occurring CD59, and were designated recombinant (r) CD59 70, 77 and 86, respectively. All three rCD59 lacked a glycosyl-phosphatidylinositol (GPI) anchor, unlike membrane CD59 which has a GPI anchor at the anchor at the carboxyl terminus (77th amino acid). Their activities in inhibiting complement activation were assayed with C5b-7 intermediate cells and C8 and C9 components. The inhibitory activity of rCD59 70 was as high as that of rCD59 77 and twice that of rCD59 86. In addition, it was one-fourth and one-hundredth lower than the activities of urine and erythrocyte CD59, respectively. However, when assayed in the presence of human serum at a final concentration of 50% (v/v), the activities of both urine and erythrocyte CD59 were greatly decreased to to one-tenth of that of rCD59 70. Purified rCD59 70 molecules were all glycosylated, but rCD59 77 and 86 were mixtures of glycosylated and non-glycosylated molecules. The inhibitory activities of rCD59 77 and 86 were the same for the glycosylated and non-glycosylated forms. These results suggest that the soluble rCD59 provide a means for elucidating the biological roles of CD59.

An immunohistochemical employer monoclonal antibodies against Le(a), sialyl Le(a), Le(x), and sialyl Le(x) antigens in primary colorectal, carcinomas and lymph node and hepatic lesions

The immunohistochemical expression of sialylated and non-sialylated forms of both Le(x) and Le(a) were studied in 87 carcinomas and 42 normal mucosal specimens of colon and rectum, as well as in 32 metastatic lymph nodes and 9 hepatic lesions, using an indirect immunoperoxidase staining. Their antigens were expressed in normal mucosa with the following frequencies: Le(a), 95.2% (40/42); sialyl Le(a), 88.1% (37/42); Le(x), 95.2% (40/42); and sialyl Le(x), 17.0% (7/42), whereas in carcinomas, the respective rate of frequency were: 78.2% (68/87); 78.2% (68/87); 90.8% (79/87); and 93.1% (81/87). Sialyl Le(x) antigen showed the highest tumor specificity compared to other antigens. In three normal mucosal specimens and four carcinomas with Le(a-b-) phenotype, the expression of type 1 antigens (Le(a) and sialyl Le(a)) was not consistent, whereas type 2 antigens (Le(x) and sialyl Le(x)) were consistently observed in carcinomas. The staining of type 1 antigens and Le(x) was decreased in metastatic lesions compared with primary carcinomas, whereas sialyl Le(x) antigen had the same positive-staining rate in both. Metastatic carcinoma expressed the sialylated form more predominantly than the non-sialylated form in type 2 antigens whereas the opposite result was observed in type 1 antigens. These results suggested that: (a) sialyl Le(x), defined by monoclonal antibody CSLEX1, may be useful as a tumor-associated antigen in colorectal carcinoma, and (b) the alteration of Lewis-related carbohydrate antigens in cancer cell membranes, including sialylation and/or aberrant glycosylation, may be related to metastatic behavior.

[CT evaluation of extravascular perfusion of contrast medium and its potential to a new method of diagnosis: an experimental study using macro, micro-molecular contrast media]

To evaluate the dynamics of extravascular perfusion, dynamic CT with two different molecular sized contrast media was performed on VX2 tumor of rabbit. The first dynamic CT was performed with a bolus injection of iopamidol (IP:120 mgI/ml, 5 ml). After ascertaining that the tumor attenuation had returned to the pre-contrast level, the second dynamic CT was performed on the same slice with bolus injection of iodoethylated starch (IES:120 mgI/ml). The time-density (T-D) curves of the same tumor area on the images obtained by two contrast media were compared. The T-D curve with IP showed definitely higher level than that with IES. This occurrence can be explained that IP, 13 A in size, has higher permeability distributing not only in the intravascular space, but also into the extravascular space. On the other hand, IES, 200 A in size, will stay mostly in the intravascular space. From this, we consider that the attenuation difference between the two curves will be an indicator for the dynamics of extravascular perfusion, suggesting to become a new method for CT diagnosis.

Effect of paraquat on the malondialdehyde level in rat liver microsomes (in vitro)

Toxicosis due to paraquat, a redox cycling xenobiotic, is still a subject of much debate. In the present study on lipid peroxidation, paraquat had a biphasic effect on the malondialdehyde (MDA) level in rat liver microsomes; stimulation at the initial stage (within 10 min) and depression at the later stage. Although paraquat increased the initial rate of NADPH oxidation dose-dependently, the rate was not necessarily parallel with the increase in the MDA level. The MDA level increased linearly up to 0.1 mM paraquat added, but then it attained a plateau. The stimulation obtained by paraquat within 10 min was absolutely dependent on exogenous Fe2+ ion and NADPH, and the stimulation was entirely SOD sensitive, while the iron-driven increase in MDA was 20% sensitive. Thus, there were different mechanisms between iron-driven lipid peroxidation and paraquat-modified peroxidation. Catalase increased the level, but mannitol, a scavenger of OH, had no effect. EPR spectra showed that superoxide was formed dose-dependently up to 0.1 mM paraquat and that it attained a plateau at the same as MDA level described above. From these results, we concluded that paraquat stimulates lipid peroxidation through a mechanism dependent on the superoxide complex involving Fe2+ ion.