Interferon-γ Produced by EBV-Positive Neoplastic NK-Cells Induces Differentiation into Macrophages and Procoagulant Activity of Monocytes, Which Leads to HLH

Simple Summary

Epstein–Barr virus (EBV), a common virus all over the world, infects not only B-cells but also T- and NK-cells. Once infected with EBV, human beings remain infected for life, and EBV renders infected B-cells immortal. EBV-positive NK-cell neoplasms, such as extranodal NK/T-cell lymphoma of nasal type, aggressive NK-cell leukemia, and chronic active EBV infection, are relatively rare but lethal disorders. They show systemic inflammation and progress to hemophagocytic lymphohistiocytosis (HLH), a life-threatening state of immune hyperactivation. The suppression and prevention of HLH are important to treat the neoplasms. Revealing the mechanism will pave a new path for treatment. We show herein that IFN-γ produced by EBV-positive neoplastic NK-cell is responsible for inducing the differentiation and the activation of M1-like macrophages. Suppressing IFN-γ may regulate HLH in EBV-positive NK-cell neoplasms.

Abstract

Epstein–Barr virus (EBV)-positive T- or NK-cell neoplasms show progressive systemic inflammation and abnormal blood coagulation causing hemophagocytic lymphohistiocytosis (HLH). It was reported that inflammatory cytokines were produced and secreted by EBV-positive neoplastic T- or NK-cells. These cytokines can induce the differentiation of monocytes into macrophages leading to HLH. To clarify which products of EBV-positive neoplastic T- or NK-cells have effects on monocytes, we performed a co-culture assay of monocytes with the supernatants of EBV-positive T- or NK-cell lines. The expression of differentiation markers, the phagocytosis ability, and the mRNA expression of the inflammatory cytokines of THP-1, a monocytic cell line, clearly increased after culturing with the supernatants from EBV-NK-cell lines. Co-culturing with the supernatants promoted the expression of CD80 and CD206 as well as M1 and M2 macrophage markers in human monocytes. Co-culturing with the supernatants of EBV-NK-cell lines significantly enhanced the procoagulant activity and the tissue factor expression of monocytes. Interferon (IFN)-γ was elevated extremely not only in the supernatant of EBV-NK-cell lines but also in the plasma of EBV-positive NK-cell neoplasms patients accompanying HLH. Finally, we confirmed that IFN-γ directly enhanced the differentiation into M1-like macrophages and the procoagulant activity of monocytes. Our findings suggest that IFN-γ may potentially serve as a therapeutic target to regulate HLH in EBV-positive NK-cell neoplasms.

AB0180 A MULTICENTER SELF-CONTROLLED CASE SERIES STUDY INVESTIGATING THE PREVENTIVE EFFECT OF SULFASALAZINE AGAINST PNEUMOCYSTIS PNEUMONIA

Background:

An animal study revealed that sulfasalazine (SSZ) enhances Pneumocystis clearance from the lung by accelerating macrophage activity.[1] Although the preventive effect of SSZ on Pneumocystis pneumonia (PCP) in patients with rheumatoid arthritis (RA) is reported in case-control studies, some important confounders might remain unmeasured and distort the results. [2-3]. The self-controlled case series (SCCS) method involves only cases and controls fixed confounders automatically.[4]

Objectives:

To evaluate the prophylactic effect of SSZ against PCP in patients with RA, controlling unmeasurable confounders by the SCCS method.

Methods:

A retrospective study was conducted at five hospitals. Patients with RA who developed PCP between 2003 and 2019 were included. PCP was defined by the following criteria: (1) detection of Pneumocystis jirovecii in respiratory specimens by polymerase chain reaction; (2) clinical manifestations (pyrexia, dry cough, dyspnea, or hypoxia); (3) diffuse interstitial infiltrate on chest imaging; (4) absence of prophylaxis for PCP. Incidence rate ratio (IRR) for Pneumocystis pneumonia associated with sulfasalazine use was calculated by conditional Poisson regression.

Results:

We identified 48 episodes of PCP in 47 cases. Of these, 15 (31.9%) died. Thirty received SSZ in certain periods of their observations (Table 1). While 46 episodes of PCP developed in the period of 168.9 person-years without SSZ use, only one episode of PCP developed in the period of 103.7 person-years with SSZ use. SSZ use had a decreased risk of PJP (adjusted IRR 0.007, 95% CI <0.001-0.067) after adjusted for age group, the use of glucocorticoid, methotrexate, and tacrolimus, and the use of biologic agent or janus kinase inhibitor (Table 2).

Table 1.

Characteristic of the 47 patients enrolled in the study.

Male/female, n (%)14 (29.8)/33 (70.2)Observational period (years), median (IQR)72.0 (66.3-79.1)Lung disease, n (%)4.7 (1.4-9.5)Use of sulfasalazine, n (%)23 (48.9)Outcome of PCP, death, n (%)30 (63.8)Age at the onset of PCP (years), median (IQR)15 (31.9)

PCP, Pneumocystis pneumonia; IQR, interquartile range.

Table 2.

Unadjusted and adjusted incidence rate ratio for Pneumocystis pneumonia associated with sulfasalazine use.

Observation length (years)Episodes of PCP, n (%)Unadjusted IRR95% CI)Adjusted IRRa(% CI)Use of SSZ103.71 (2.1)0.010 (0.001-0.092)0.007 (<0.001-0.067)No use of SSZ168.947 (97.9)referencereference

IRR, incidence rate ratio; PCP, Pneumocystis pneumonia; SSZ, sulfasalazine.

Conclusion:

Our study demonstrated the preventive effect of SSZ against PCP with confounders controlled by the SCCS.

References:

[1]Wang, J., et al. Immune modulation with sulfasalazine attenuates immunopathogenesis but enhances macrophage- mediated fungal clearance during pneumocystis pneumonia. PLoS Pathog. 2010;19;6(8):e1001058.

[2]Nunokawa, T. et al. Prophylactic effect of sulfasalazine against Pneumocystis pneumonia in patients with rheumatoid arthritis: A nested case-control study. Semin. Arthritis Rheum. 2019;48(4):573-578.

[3]Nunokawa, T., et al. Effect of Sulfasalazine Use on the Presence of Pneumocystis Organisms in the Lung among Patients with Rheumatoid Arthritis: A Test-Negative Design Case-Control Study with PCR Tests. Mod. Rheumatol. 2019;29(3):436-440.

[4]Petersen, I., et al. Self controlled case series methods: an alternative to standard epidemiological study designs. BMJ. 2016;12;354:i4515.

Disclosure of Interests:

None declared

Lateral Asymmetry and Spatial Difference of Iron Deposition in the Substantia Nigra of Patients with Parkinson Disease Measured with Quantitative Susceptibility Mapping

BACKGROUND AND PURPOSE

Quantitative susceptibility mapping is useful for assessing iron deposition in the substantia nigra of patients with Parkinson disease. We aimed to determine whether quantitative susceptibility mapping is useful for assessing the lateral asymmetry and spatial difference in iron deposits in the substantia nigra of patients with Parkinson disease.

MATERIALS AND METHODS

Our study population comprised 24 patients with Parkinson disease and 24 age- and sex-matched healthy controls. They underwent 3T MR imaging by using a 3D multiecho gradient-echo sequence. On reconstructed quantitative susceptibility mapping, we measured the susceptibility values in the anterior, middle, and posterior parts of the substantia nigra, the whole substantia nigra, and other deep gray matter structures in both hemibrains. To identify the more and less affected hemibrains in patients with Parkinson disease, we assessed the severity of movement symptoms for each hemibrain by using the Unified Parkinson's Disease Rating Scale.

RESULTS

In the posterior substantia nigra of patients with Parkinson disease, the mean susceptibility value was significantly higher in the more than the less affected hemibrain substantia nigra (P < .05). This value was significantly higher in both the more and less affected hemibrains of patients with Parkinson disease than in controls (P < .05). Asymmetry of the mean susceptibility values was significantly greater for patients than controls (P < .05). Receiver operating characteristic analysis showed that quantitative susceptibility mapping of the posterior substantia nigra in the more affected hemibrain provided the highest power for discriminating patients with Parkinson disease from the controls.

CONCLUSIONS

Quantitative susceptibility mapping is useful for assessing the lateral asymmetry and spatial difference of iron deposition in the substantia nigra of patients with Parkinson disease.

Visualization of the Medial and Lateral Geniculate Nucleus on Phase Difference Enhanced Imaging

BACKGROUND AND PURPOSE

The precise identification and measurement of the medial geniculate nucleus and lateral geniculate nucleus on MR imaging remain technically challenging because the thalamic nuclei are small structures. We compared the visualization of the medial geniculate nucleus and lateral geniculate nucleus on phase difference enhanced imaging with 3D high-resolution phase imaging, 2D-T2WI, STIR, proton attenuation-weighted imaging, and DTI acquired at 3T. We also measured the volume and height of the medial geniculate nucleus and lateral geniculate nucleus on phase difference enhanced imaging.

MATERIALS AND METHODS

Phase difference enhanced, 2D-T2-weighted, STIR, proton attenuation-weighted, and DTI were acquired on a 3T MR imaging unit in 10 healthy volunteers. Two neuroradiologists recorded the qualitative visualization scores of the medial geniculate nucleus and lateral geniculate nucleus, specifically the identification of their boundaries, for all images. Measurement differences were assessed with the Wilcoxon signed rank test. The volume and height of the medial geniculate nucleus and lateral geniculate nucleus were measured on phase difference enhanced imaging and compared with previously reported values.

RESULTS

The qualitative visualization scores of the lateral geniculate nucleus and medial geniculate nucleus were significantly higher on phase difference enhanced images than on T2-weighted, proton attenuation-weighted, STIR, or DTI (P < .05). On phase difference enhanced imaging, the medial geniculate nucleus and lateral geniculate nucleus were bordered by low-intensity structures: the cerebral peduncle, the origin of the optic radiation, and the superior and inferior quadrigeminal brachia. The volume of the medial geniculate nucleus and lateral geniculate nucleus varied from 74.0 to 183.75 mm(3) (mean, 129.0 ± 34.7 mm(3)) and from 96.5 to 173.75 mm(3) (mean, 135.2 ± 28.0 mm(3)), respectively.

CONCLUSIONS

For the depiction of the medial geniculate nucleus and lateral geniculate nucleus on 3T MR imaging, phase difference enhanced imaging is superior to conventional MR imaging. The medial geniculate nucleus and lateral geniculate nucleus volumes vary among individuals.

[Huge right atrial myxoma]

Myxomas are account for approximately half of primary cardiac tumors, and 75% cases originate in left atrium. We report our experience of a right atrial myxoma. A 68-year-old woman was referred to us due to anorexia, general fatigue and facial edema. Echocardiogram, computed tomography (CT), magnetic resonance imaging (MRI), and catheter angiocardiogram revealed a huge tumor in right atrium. The tumor was resected completely with the attached right atrial free wall under cardiopulmonary bypass. Pathological examination showed myxomatous tissue. Postoperative course was uneventful. She discharged the hospital on the 37th day after the operation, and is now doing well without any symptoms.

[Valve-in-valve replacement of primary tissue valve failure of bovine pericardial valve minor]

A 73-year-old woman who underwent mitral valve replacement with a 31 mm Carpentier Edwards Pericardial Xenograft 19 years ago. She revealed sudden onset of a grade IV/VI a seagull like diastolic murmur at the apex, and severe hematuria. Echocardiography demonstrated severe mitral regurgitation. These findings were consistent with acute primary tissue valve failure. Therefore we performed emergency reoperation. At operation, valve leaflet was torn at the commissural stitch, and bioprosthesis strut was buried in the left posterior ventricular wall. The mitral prosthetic valve replaced with a 25 mm CarboMedics OptiForm using a technique of valve-in-valve replacement. This procedure would be one option for replacement of bioprosthetic mitral valve.

Mexiletine carbonyloxy beta-D-glucuronide: a novel metabolite in human urine

1. The study was performed to isolate and characterize a glucuronic acid conjugate of mexiletine that releases mexiletine on acid hydrolysis from urine samples obtained from healthy volunteers following a single oral dose of mexiletine. 2. The [M-H]- ion of the isolated metabolite was observed at m/z 398 in the negative electrospray ionization mass spectrum. This mass number was 44 higher than that of the product generated when mexiletine is subjected to direct glucuronidation. In positive-ion mode, collision-induced dissociation of the quasimolecular ion [M+NH4]+, m/z 417, gave product ions at m/z 224, 180 and 58. These mass spectral data indicated that the metabolite contained a carbonyloxy moiety in its structure in addition to mexiletine and a glucuronic acid moiety. 3. The presence of this carbonyloxy moiety was further supported by the following chemical reactions. When the metabolite was hydrolysed with an aqueous solution of 1 M sodium hydroxide at room temperature, mexiletine was released, whereas the N-methoxycarbonyl derivative of mexiletine was obtained after treatment of the metabolite with methanolic sodium hydroxide solution. 4. The results indicated that the structure of the isolated metabolite was the N-carbonyloxy beta-D-glucuronic acid conjugate of mexiletine.

Interindividual variation in the ratio between plasma morphine and its metabolites in cancer patients

In 25 cancer patients treated with slow-release oral morphine and in 10 cancer patients treated with continuous infusion of morphine, plasma steady-state concentrations of morphine (M), morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) were determined by high-performance liquid chromatography. Blood samples were withdrawn at 0, 2 and 6 h after oral administration in patients treated with slow-release oral morphine and once or twice a day in patients treated with continuous infusion of morphine. In four cancer patients treated with continuous infusion of morphine, in order to analyze chronopharmacokinetic variability, the M-3-G/M ratio was observed at 12:00 h and 24:00 h. No significant changes were observed in M-3-G/M ratios and M-6-G ratios at 0, 2, and 6 h after oral administration of morphine. The M-3-G/M ratio (38.6 +/- 25.7) in the oral morphine group was significantly higher than that (15.3 +/- 12.9) in the continuous infusion group (p < 0.01). There was an approximately 10-fold interindividual variation in the M-3-G/M ratio both in the continuous infusion group and in the oral morphine group. These results suggest that the activity of UDP glucuronosyltransferase 2B7 in the intestinal metabolism of morphine may play an active part in a large interindividual variation in the ratio of metabolites to morphine. Further studies are needed to clarify this hypothesis.

Synovial histology in three Behçet's disease patients with orthopedic surgery

Specimens of synovial tissues from 5 affected joints of 3 patients with Behçet's disease were available for histopathological examination. All specimens were infiltrated by lymphocytes and neutrophils, and exhibited marked vascularity and infiltration of lymphoid cells among the vessels. Marked plasma cell infiltration and lymphoid follicle formation were found in one synovial tissue sample. There was no evidence of infection or vasculitis. These findings suggest that the histopathological characteristics of synovial tissue in Behçet's disease may have a wide range, some of which may even resemble the synovial tissue of rheumatoid arthritis.

Detection and cytotoxicity of cisplatin-induced superoxide anion in monolayer cultures of a human ovarian cancer cell line

Superoxide anions (O2-) generated by cisplatin [cis-diamminedichloroplatinum (II), DDP] were determined by measuring the chemiluminescence from the luminescence probe, 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (methyl Cypridina luciferin analog, MCLA), in monolayer cultures of a human ovarian cancer cell line (A2780) in physiological saline at pH 7.0. In a time-course study, chemiluminescence of MCLA (C-MCLA) showed a peak level at 10 min and a background level at 60 min after the addition of DDP. The intensity of C-MCLA increased with increasing concentrations of DDP or MCLA in a limited concentration range, and was significantly correlated (r = 0.960) with the number of A2780 cells. DDP-induced C-MCLA was completely inhibited by the addition of the O2- scavenger, superoxide dismutase (SOD). However, SOD did not decrease DDP cytotoxicity in terms of clonogenic cell survival. These findings suggest that DDP generates extracellular O2-, probably by interaction with the cellular membrane in A2780 cells, and O2- does not lead to cellular damage.

The progression of invasiveness regarding the role of transforming growth factor beta receptor type II in gastric cancer

AIMS

Transforming growth factor beta (TGF beta) is a potent growth inhibitor of epithelial cells. The expression of TGF beta receptors is required for the effect of TGF beta. In this study, we used immunohistochemistry to demonstrate the roles of the expression of TGF beta type I (T beta R-I) and type II (T beta R-II) receptors in the progression of gastric carcinoma.

METHODS

To evaluate the potential prognostic value of T beta R-I and T beta R-II, 158 consecutive gastric cancer tissues specimens obtained over a 3-year period were examined.

RESULTS

A total of 50 (32%) and 28 (18%) patients had T beta R-I(+) and T beta R-II(+), respectively. The 5-year survival rates of the patients with T beta R-I(+) and those with T beta R-I(-) were 74% and 71%, respectively. In contrast, the 5-year survival rates of the patients with T beta R-II(+) and those with T beta R-II(-) were 57% and 75%, respectively, and the difference was statistically significant (P<0.05). The extent of T beta R-II was closely correlated to the macroscopic types based on the Borrmann classification (P<0.01), and curability (P<0.05). However, a significant difference between the 5-year survival rates of the patients with T beta R-II(+) and those with T beta R-II(-) was only obtained in advanced cases (P<0.05) not in either curative cases, non-curative cases, or early cases.

CONCLUSIONS

Our data suggest that when T beta R-II expression correlates with the progression of invasiveness in gastric cancer, it may lead to a non-curative resection and a poor prognosis.

Pharmacokinetics of [125I]-recombinant human interleukin-11: 2. Placental transfer and excretion into milk after subcutaneous administration to rats

Placental transfer and excretion into milk of [125I]-rhIL-11 (recombinant human interleukin-11) after subcutaneous administration in female rats were investigated. After administration of [125I]-rhIL-11 to rats on the 14th day of gestation, radioactivity in the kidney was the highest among excised tissues, being 3 times higher than that in the plasma at 1.5 h. Radioactivity in other tissues, including the mammary gland, ovary, uterus, placenta and amniotic fluid, was lower than that in the plasma. Although radioactivity in fetuses was detected 6 h after administration, the level was only 2% of the plasma concentration in dams, and the radioactivity was not found in fetal-derived TCA precipitates. These results indicate that rhIL-11 does not readily pass through the placenta into the fetus. After subcutaneous administration of [125I]-rhIL-11 to lactating rats 14 days after delivery, radioactivity in milk was 1.1-1.6 times that in the plasma of dams. Radioactivity in clotted milk in the stomachs of suckling infants was almost equal to that in the dam's milk; however, only a small amount of radioactivity was detected in infant kidneys.

Pharmacokinetics of [125I]-recombinant human interleukin-11: 1. Absorption, distribution and excretion after subcutaneous administration to male rats

Absorption, distribution, metabolism and excretion of [125I]-rhIL-11 (recombinant human interleukin-11) after subcutaneous administration in rats were investigated. After a single administration, the concentration of radioactivity in the tissues was 2-6-fold higher in the liver and kidneys, and slightly higher in the gastrointestinal tract as compared to the plasma concentration. However, since the concentration in the other tissues was lower than the plasma concentration, the transport of rhIL-11 into tissues appeared to be low. Tissue radioactivity rapidly diminished, thus accumulation of rhIL-11 in tissues was thought to be low. Excretion of radioactivity into urine and feces was almost complete 72 h after administration, with 88.5% of the dosed radioactivity being found in urine and 7.9% in feces. When [125I]-rhIL-11 was administered to bile-duct cannulated rats, 44.4% of the dosed radioactivity was excreted into bile up to 48 h after administration. Most radioactivity in bile and urine was found in the TCA supernatant and low molecular weight fraction by HPLC analysis, indicating that rhIL-11 was eliminated from the body by metabolism.

Long-term results of corticosteroid administration via appendicostomy in patients with ulcerative colitis involving the entire colon

BACKGROUND

Ulcerative colitis (UC) of an unknown etiology frequently demonstrates repeated active and inactive stages. As a result, it is difficult to sustain long-term remission under conservative therapy.

METHODS

Ten patients who presented suffering from UC involving the entire colon were treated. All patients had been previously treated at other hospitals usually with sulphasalazine and either corticosteroids or steroid enemas for the primary complaints of muco-bloody stool or frequent diarrhea. All patients underwent either an appendicostomy or cecostomy, and were injected with dexamethasone via an artificial fistula twice a day.

RESULTS

This treatment led to remission, and, as a result, the symptoms of anal bleeding or muco-bloody stools disappeared in all patients. Radiological, endoscopic, and pathological studies revealed a dramatic response to steroid injection from the fistula. The mean follow-up period was 44.7 months (3-122 months). Eight patients remained free from any symptoms of UC. One underwent a proctocolectomy because of side effects due to steroid treatment. The other patient died suddenly of unknown causes. The mean symptom-free period after cecal injection was 39.5 months (1-119 months). The mean proportion of disease free period from UC, compared with the total follow-up period after surgery, was 88%. After remission, eight patients were able to return to a normal lifestyle at home using a peritoneal button. They could also take a bath and continue their school or social lives in almost the same way as healthy persons.

CONCLUSIONS

We thus recommend this new, minimally-invasive therapy for patients with UC involving the entire colon who demonstrate resistance to conventional conservative therapy. As a result of such treatment, all patients were able to achieve a comfortable lifestyle after undergoing minimally-invasive surgery.

Anthelmintic efficacy of milbemycin oxime against Trichuris vulpis in dogs

The anthelmintic efficacy of milbemycin oxime against dog whipworm, Trichuris vulpis, was evaluated. A total of 21 T. vulpis positive dogs were divided into 3 groups, one (5 dogs) for control and the other two (8 dogs each) for anthelmintic treatment with oral administration of milbemycin oxime.

Development of microplate-radioluminography for 32P

Basic research for designing a microplate which can be applied to determination of 32P by radioluminography was carried out. It was proven that 32P can be determined by using the microplate which has plural planchets placed at intervals on a thin plate and a brass collimator that fills the gaps between the planchets. The microplate is joined with the collimator, and exposed to an imaging plate for 24 h. The detection limit of the proposed method was estimated to be 6 m Bq. The cross-talk ratio was negligibly small (0.2%).

Sensitive enzyme-linked immunosorbent assay (ELISA) to measure parasite-specific antibodies of Indian soft-furred rats, Millardia meltada

Immunoglobulin G (IgG) of Indian soft-furred rat, Millardia meltada, was purified by an immunoaffinity chromatography and antibodies against it was raised in rabbit. Using this rabbit anti-M. meltada IgG antibody, sensitivity of enzyme-linked immunosorbent assay (ELISA) to measure parasite-specific antibodies in the sera of M. meltada was markedly enhanced than the previous method using rabbit anti-mouse IgG and rabbit anti-rat IgG antibodies, which could cross-react to M. meltada IgG. Since M. meltada could effectively produce circulating antibodies against two intestinal helminths, Strongyloides venezuelensis and Nippostrongylus brasiliensis, the high susceptibility of this animal to an array of parasites seems to be not due to general immunological deficiency.

[Cyclophosphamide pulse therapy for refractory rheumatic diseases]

We studied the efficacy of cyclophosphamide pulse therapy (CYP) for refractory rheumatic diseases except for lupus nephritis. Thirty-five patients were included in all, that is 9 patients with systemic lupus erythematosus (SLE), 10 with rheumatoid arthritis (RA), 7 with polymyositis/dermatomyositis (PM/DM), 2 with progressive systemic sclerosis (PSS), 2 with anti-phospholipid antibody syndrome (APS), 1 with mixed connective tissue disease (MCTD), 1 with juvenile rheumatoid arthritis (JRA), 1 with Behcet's disease (BD), 1 with Wegener's granulomatosis (WG) and 1 with allergic granulomatous angiitis (AGA). Moderate to marked improvement was noted in 4 patients with SLE (2 with CNS-lupus and 2 with vasculitis), 7 with RA (2 with interstitial pneumonia:IP, 2 with vasculitis and 2 with refractory arthritis), 4 with PM/DM (2 with IP and 2 with refractory myositis), 1 PSS with IP, 2 APS with thrombocytopenia, 1 JRA with vasculitis and BD with CNS disturbance. On the other hand, adverse reactions were observed in 9 out of 35 patients (25.8%). CYP should apply in the treatment for such refractory rheumatic diseases as CNS disturbance, vasculitis, IP and autoimmune thrombocytopenia.

Organotin compounds and polychlorinated biphenyls of livers in squid collected from coastal waters and open oceans

The current status of global marine pollution by TBT (tributyltin), TPT (triphenyltin) and polychlorinated biphenyls (PCBs) was examined by determining their concentrations in squid livers. TBT and TPT concentrations in squid livers were higher in coastal waters than in open oceans. The highest values of TBT and TPT of 279 and 519 ng g(-1), respectively, were detected off Japan. TBT concentrations were higher in the northern hemisphere than those of the southern hemisphere organisms. TPT was not detected in squid livers collected in the southern hemisphere. The variation in TBT and TPT concentrations between the northern and the southern hemisphere was greater than those recognized for PCBs distribution in the world oceans. This global distribution pattern of TBT, TPT and PCB seemed to reflect their usage (amount, period and manner of utilization). Approximate TBT concentrations in seawater estimated from bioaccumulation factor in the squid liver were 0.1-5.8 ng litre(-1) in waters around Japan, tr-0.8 ng litre(-1) in oceanic waters in the northern hemisphere, and tr-0.4 ng litre(-1) in the southern hemisphere oceans.

Intravenous immunoglobulin therapy for refractory myositis

The efficacy of polyvalent intravenous immunoglobulin therapy (IVIG) was evaluated in three patients with refractory myositis. Patients refractory to conventional therapy, such as corticosteroid administration, corticosteroid or cyclophosphamide pulse therapy [2 with dermatomyositis (DM), 1 with polymyositis (PM)] were treated with IVIG (0.4 g/kg daily) for 5 days. Clinical improvement was apparent within 1-2 months after IVIG and persisted for 19-23 months (DM patients) and 12 months (PM patient). No adverse effects were observed. Thus, IVIG may be considered an effective therapy for refractory myositis.

[Primary biliary cirrhosis in patients with Sjögren's syndrome]

Primary biliary cirrhosis (PBC) is one of the most frequent hepatic diseases associated with Sjögren's syndrome (SS), its reported incidence ranging from 3% to 9%. There is much association between SS and PBC in the pathogenesis. In both diseases, autoimmunity seems to be directed toward the ductal epithelial cells. Epstein Barr Virus may contribute to PBC, as well as SS. PBC associated with SS tends to be asymptomatic and to be in an early stage in histologically. Antimitochondrial antibody (AMA) is the most sensitive indicator of PBC in primary SS. When SS patients have an elevated alkaline phosphatase level, it is necessary to examine AMA and to perform liver biopsy.

Characteristics of non-small cell lung cancer 3 cm or less in diameter

We retrospectively investigated 308 cases of non-small cell lung cancer of < or = 3 cm diameter. There were 204 adenocarcinomas, 78 squamous cell carcinomas, 15 large cell carcinomas, and 11 other carcinomas. According to TNM staging, there were one case stage 0, 208 stage I, 22 stage II, 49 stage IIIA, 15 stage IIIB, and 13 cases stage IV. T1 disease was seen in 262 cases, T2 in 19, T3 in 10, T4 in 16, and Tis in 1. N0 disease was seen in 217 cases, N1 in 30, N2 in 60, and N3 in 1. The 5-year survival rate of all cases was 63%. There were statistically significant differences among T status (T1 vs. T3, T4), N status (N0 vs. N1, N2), and M status (M0 vs. M1) (P < 0.01). The 5-year survival rates of cases with adenocarcinoma and squamous cell carcinoma were 60% and 64%, respectively. In 204 cases of adenocarcinoma, T3 disease was found in one case, T4 disease in 15 (7%), and nodal involvement (N1 + N2) was present in 69 (34%). In 78 cases of squamous cell carcinoma T3 was seen in 6 (8%), T4 in 1, and nodal involvement in 14 (18%). The incidence of T3 disease, T4, and N(+) varied significantly according to histology (P < 0.05). Our investigation suggested that cases of small-sized lung cancer were often at an advanced stage at detection, and that the spread of disease differed according to histology. The patient with small-sized lung cancer should be offered a standard operation regardless of histology.

The close relationship between growth factors and the nucleolar organizer regions in adenocarcinoma of the lung

We examined immunohistochemically 111 cases of primary adenocarcinoma of the lung, for transforming growth factor alpha (TGF alpha) or epidermal growth factor (EGF), and argyrophilic nucleolar organizer regions (AgNORs). The presence of more than 75% positive cells for both growth factors was designated as a high-GF, while all others were considered to be a low-GF. If AgNORs counts were more than 5.00, it was considered to be a high-AgNORs group, while less than 5.00 was designated as a low-AgNORs group. In our 111 examined specimens, there were 51 (46%) cases of high-GF, and 64 (58%) with high AgNORs. The 5-year survival rates of the patients with a high-GF and low-GF were 34% and 57% (P < 0.05) respectively, while those with high-AgNORs and low-AgNORs were 21% and 81% (P < 0.001), respectively. In the cases of high-AgNORs, the 5-year survival rates of the patients with high-GF and low-GF were 0% and 36% (P < 0.05), respectively. However, in the cases of low-AgNORs, the 5-year survival rates of the patients with high-GF and low-GF were 83% and 79%, respectively. These data suggest that growth factors might be related to the biological malignancy of tumours with a high cell proliferation.

Neurogenic tumors of the mediastinum originated from the vagus nerve

Thirty-nine patients with neurogenic tumors observed between 1974 to 1992 were reviewed. There were 32 patients with neurilemoma, one with neurofibroma, five with ganglioneuroma, and one with malignant neurilemoma. Two cases of neurilemoma originated from the vagus nerve, which is very rare. Surgical resection is recommended, not only to confirm the nature of the lesion, but also to prevent further growth and compression on adjacent structures. For benign encapsulated neurogenic tumors, resection is curative.

Lymph node cancer of the mediastinal or hilar region with an unknown primary site

We herein report three cases of lymph node cancer of the mediastinal or hilar region, in which the primary sites could not be determined in spite of performing various systemic examinations. Two cases revealed a large cell anaplastic carcinoma in the mediastinal lymph node, while the other demonstrated a small cell carcinoma in the hilar lymph node. However, based on radiographic and pathological examinations, the primary sites could not be found in either the head and neck, lung, or abdominal organs. All cases underwent surgical resections for lymph node cancer, while two patients also received adjuvant therapy. Two patients experienced recurrence soon after treatment. Despite the rarity of this disease, lymph node cancer must always be kept in mind when an enlargement of either the mediastinal or hilar lymph node is detected in patients with an unknown primary site, and a poor prognosis is generally expected.

Immunologic characteristics of anti-erythrocyte membrane antibody produced in dogs during Babesia gibsoni infection

Serum anti-erythrocyte membrane (RBCm) antibodies and anti-RBCm antibodies eluted from erythrocytes of Babesia gibsoni-infected dogs were examined for immunologic characteristics by immunoblotting analysis. Serum anti-RBCm antibodies of the dogs before and after the experimental inoculation with parasitized erythrocytes reacted with cytoskeletal (bands 1, 2, 2.1, 4.1, 4.2 and 5) and transmembrane structural (band 3) proteins of either self or non-self RBCm. Anti-RBCm antibodies eluted from erythrocytes of B. gibsoni-infected dogs reacted with bands 3 and 4.2 of self and non-self RBCm.

Recurrent pattern of digestive tract carcinoma in the Japanese: comparison of gastric cancer to colon cancer

Six hundred and two consecutive cases of gastric cancer and 204 of colorectal cancer in recent decades were investigated for recurrence. Recurrence occurred in 103 cases of gastric cancer and 31 cases of colorectal cancer. We classified three categories of recurrent patterns; A: local, B: peritoneal dissemination, and C: distant metastasis. In gastric cancer, 11 cases (11%) were grouped A, 50 (48%) were B, and 42 (41%) were C. Similarly, 12 (39%) were grouped A, 5 (16%) were B, and 14 (45%) were C in colorectal cancer. The incidence of local recurrence was more increased in colorectal cancer than in gastric cancer (p < 0.01). On the contrary, that of peritoneal dissemination was more increased in gastric cancer than in colorectal cancer (p < 0.01). In gastric cancer, 8 cases of 103 survived more than 5 years after operation, furthermore 7 cases obtained more than 5 years of tumor-free interval. At the time of diagnosis of recurrence, data of serum CEA was available in 77 for gastric cancer and 29 for colon cancer. CEA positive cases were revealed 32 (42%) for gastric cancer and 24 (83%) for colorectal cancer (p < 0.01). Our data clarified the different recurrence patterns between gastric cancer and colorectal cancer. And suggest that more than 5 years follow-up should be needed in patients with gastric cancer.

Malignant pleurisy and intrathoracic dissemination in carcinoma of the lung: diagnostic, therapeutic and prognostic implications

Of T4 disease of lung cancer, malignant pleurisy and intrathoracic dissemination are the greatest factor preventing a cure, despite the best efforts of surgery and various adjuvant therapy modalities. Preoperative evaluation of this disease is of first importance using conventional radiology and computed tomography. Of the 43 patients who were intraoperatively diagnosed to be the disease, 8 (18%) appeared on the conventional radiology as small amounts of pleural effusion, and 9 (21%) with a interlobar pleural thickening. Based on CT findings, 16 (67%) had one or more of some disseminated nodules, interlobar pleural thickening and broad pleural indentation. In patients with T4 disease, the 5-year survival rate was 14% in patients with malignant pleurisy and/or intrathoracic dissemination, compared with the 18% in those with direct invasion to great vessels, with no significant difference. According to intrapleural instillation as postoperative adjuvant therapy, the 5-year survival rate was 25% in the patients given interleukin-2, compared with 38 months of survival time for patients prescribed doxorubicin and 33 months for those underwent exploratory thoracotomy. A more favorable prognosis of patients whose malignant pleurisy and/or intrathoracic dissemination are first found at thoracotomy can be expected when postoperative intrapleural instillation of interleukin-2 is prescribed following the resection of the intrathoracic tumors.

Skip mediastinal lymph node metastasis in non-small cell lung cancer

We retrospectively investigated 186 non-small cell lung cancer cases with N2 disease in order to clarify the significance of skip metastasis. Of the 186 patients with N2 disease, negative N1 nodes recognized to be skip metastasis were seen in 62 patients (33%). The incidence of skip metastasis was not statistically different regarding histology, T status, or M status. The incidence of the skip metastatic site consisted of 35 cases (56%) at sites 1, 2 and 3, while 8 cases (13%) were found at sites 8 and 9. Among the patients with right lung cancer, the skip metastatic incidence for site 7 (subcarinal) was higher in patients with either middle lobe or lower lobe cancer than in those with upper lobe cancer (P < 0.05). The 5-year survival rates of all N2 patients in comparison to those with skip metastasis were 22% and 24%, respectively. When the sites of mediastinal lymph nodes were classified as superior, aortic, and inferior, the 5-year survival rates of the patients with superior skip metastasis, aortic metastasis, and inferior metastasis were 23%, 36%, and 15%, respectively. No statistical difference was observed. The 5-year survival rate of the skip N2 patients with only aortic region involvement was 50% (n = 7). However, no statistically significant difference was found between the two groups (P = 0.08). Our results thus suggested that mediastinal involvement for the aortic region alone might have a better prognosis than the others. We thus conclude that a dissection of the complete hilar and mediastinal lymph nodes should be the procedure of choice in standard operations for non-small cell lung cancer because of the high frequency of skip metastasis.

Reactivity of serum anti-erythrocyte membrane antibody in Babesia gibsoni-infected dogs

Reactivity of anti-erythrocyte membrane (RBCm) antibody in sera of B. gibosni-infected dogs on native RBCm and erythrocyte surface (RBCs) was examined using an enzyme linked immunosorbent assay. Anti-RBCm antibody attached to native RBCm and the surface of erythrocytes (RBC) treated with phenylhydrazine or neuraminidase, but not to the surface of non-treated RBC. Based on these results, anti-cytoskeletal protein antibody in sera of B. gibsoni-infected dogs is considered to attach to native RBCm, and furthermore free radical-induced oxidative stress imposed on RBC and sialic acid removal from glycoproteins of RBC are considered necessary for anti-transmembrane protein antibody in sera of B. gibsoni-infected dogs to be bound to RBCs. These are important to elucidating the mechanism of the marked increase in RBCs-bound IgG value and anemia in B. gibsoni infection.

Elevated erythrocyte-bound IgG value in dogs with clinical Babesia gibsoni infection

Erythrocyte (RBC)-bound IgG values (IgG concentration, ng/ml) were examined in 8 Babesia gibsoni-infected and 10 healthy dogs by a competitive enzyme immunoassay. Five dogs with clinical B. gibsoni infection, manifesting severe anemia, were observed to have increased RBC-bound IgG values compared to dogs with subclinical B. gibsoni infection and healthy controls, this suggesting that anemia in B. gibsoni infection may be explained in part on the basis of a humoral immunologic mechanism.

DNA polymerase alpha as an independent prognostic parameter in non-small cell lung cancer--an immunohistochemical study

We examined 70 fresh frozen sections of primary non-small cell lung cancer using a monoclonal antibody for DNA polymerase alpha (POL alpha). The tumors were divided into two groups; those with more than 5% of POL alpha positive cells were designated as POL alpha (+), while those with less than 5% were POL alpha (-). POL alpha (+) tumors were obtained in 33 (47%) cases. The incidence of POL alpha (+) in male patients was statistically higher than in females (P < 0.01). The incidence also correlated with the T(tumor) status; T1 < T2, T1 < T4, with a significance (P < 0.05). Based on data on 70 patients, the 5-year survival rates of POL alpha (+) and POL alpha (-) were 36% and 63%, respectively (p < 0.05). In 48 patients with adenocarcinoma, the 5-year survival rates of POL alpha (+) and POL alpha (-) were 25% and 60%, respectively (P < 0.05). In addition, in 26 patients with a tumor size of less than 3 cm, the 5-year survival rates of POL alpha (+) and POL alpha (-) were 13% and 74%, respectively (P < 0.01). To compare the prognostic significance of the variables, a multivariate analysis was used to show significance for survival in POL alpha (p < 0.05). Our data show that in non-small cell lung cancer, POL alpha expression is associated with the extent of malignancy and survival. Therefore, POL alpha is considered to be a useful prognostic parameter.

Prognostic influence of the co-expression of epidermal growth factor receptor and c-erbB-2 protein in human lung adenocarcinoma

The epidermal growth factor receptor (EGFR) is structurally similar to the c-erbB-2 oncogene protein. One hundred and nineteen specimens of primary human lung adenocarcinoma were investigated immunohistochemically for the expression of EGFR and the c-erbB-2 protein. Positive staining for EGFR was evident in 55 (46%), and c-erbB-2 protein in 33 (28%) cases. Of the 119 cases, the number staining positively for both the EGFR and c-erbB-2 protein totalled 16 (13%). The incidence of both the expression of EGFR and the c-erbB-2 protein was greater in patients with metastasis1 (M1) than in those with M0 (P < 0.01). The 5-year survival rates of patients with EGFR positivity and those with EGFR negativity were 51% and 42% respectively, however, the results did not show statistical significance. On the other hand, the 5-year survival rates of patients with c-erbB-2 positivity and c-erbB-2 negativity were 30% and 52%, respectively, with statistical significance (P < 0.05). Of the cases with EGFR positivity the 5-year survival rates of patients with c-erbB-2 positivity (n = 16) and negativity (n = 39) were 33% and 59%, respectively, with statistical significance (P < 0.05). In contrast, for the EGFR negative cases, the 5-year survival rates of patients who were positive (n = 17) and negative (n = 47) for c-erbB-2 expression were 27% and 46%, respectively, which were not significantly different. Our data thus suggested that erbB oncogenes may play an important role in both the development of cancer and the prognosis of adenocarcinoma of the lung.

Existence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols in lipoproteins from diabetic patients and normal subjects

We report evidence for the presence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols (cholesterol 7-hydroperoxides, Ch 7 alpha-OOH and Ch 7 beta-OOH, respectively) in human plasma lipoproteins in vivo, which had been reported to be markers of aging in rat skin. A comparative study was carried out focusing on the detection of Ch 7-OOHs in plasma lipoproteins from diabetic patients whose plasma has been suggested to be under high oxidative stress. Blood samples were collected from healthy volunteers (control) and diabetics with and without hypercholesterolemia. Ch 7-OOHs were isolated from low and high density lipoproteins (LDL and HDL, respectively) in the plasma of these subjects, identified, and determined by high-performance liquid chromatography with a chemiluminescence detector. The percent detection of Ch 7-OOHs in LDL from diabetics without hypercholesterolemia was similar to that in the control group. However, it was significantly higher in diabetics with hypercholesterolemia than in those without hypercholesterolemia. The percent detection of Ch 7-OOHs in HDL from diabetics without hypercholesterolemia was higher than both that in LDL from the same group and that in HDL from the control group.

Neoadjuvant chemotherapy in patients with small-cell lung-cancer - radiographic and clinicopathological analysis

A comparative study on the effect of neoadjuvant chemotherapy was performed for small cell lung cancer, by radiographic and histopathological examinations. Four patients with small cell lung cancer were preoperatively treated with the combination of cyclophosphamide, doxorubicin, vincristine, nimustine, cisplatin and vindesine, for 2 to 3 cycles. The clinical responses to the neoadjuvant chemotherapy included 2 complete, one partial response and one no change. All four patients underwent a planned operation. Based on microscopical evidence, the two complete responders had a residual tumor in the resected specimens. One was tumor-free after 28 months, while the other succumbed to operation-related death at 2 months. The remaining two inadequate responders relapsed and died shortly following operation. We believe a clinically complete responder should be differentiated from a 'true' complete responder by histopathological examination.

Proliferating cell nuclear antigen expression and argyrophilic nucleolar organizer regions as factors influencing prognosis of surgically treated lung cancer patients

Cell proliferation in 211 primary non-small cell lung carcinomas was assessed by using an immunostaining of proliferating cell nuclear antigen (PCNA) and a silver staining of argyrophilic nucleolar organizer region (Ag-NOR). More than 5% PCNA positive cells was designated PCNA(+), and less than 5% was PCNA(-). A mean number or more of the Ag-NOR was a high Ag-NOR count, and less than the mean number was a low Ag-NOR count. The proportion of the tumors with PCNA(+) and high Ag-NOR counts showed an increase in patients in an advanced stage of the disease (P < 0.05). In 125 patients with stage I disease, the 5-year survival rate was 20% in patients with PCNA(+) and high Ag-NOR counts, compared with 47% in those with either PCNA(+) or high Ag-NOR counts and 76% in those with PCNA(-) and low Ag-NOR counts (P < 0.05). Our data suggest that the tumors with PCNA(+) and high Ag-NOR counts have a high proliferative activity. The combination analysis of PCNA and Ag-NOR may be useful in assessing prognosis in lung cancer, even in stage I disease.

A novel pathway for formation of thiol metabolites and cysteine conjugates from cysteine conjugate sulphoxides

p-Bromothiophenol and S-(p-bromophenyl)-L-cysteine were formed enzymatically from S-(p-bromophenyl)-L-cysteine sulphoxide in the in vitro systems with isolated rat hepatocytes or purified cysteine conjugate beta-lyases. Isotope dilution study with non-radiolabelled carrier of each product suggested the initial liberation of the thiol and subsequent formation of the cysteine conjugate. C-S bond cleavage pathway to liberate sulphenic acid and thiol are postulated to play an important role in in vivo generation of toxic intermediates and products from cysteine conjugates.

Mediastinal tumor and application of thoracoscopic surgery

Thoracoscopic resection of a mediastinal tumor or cyst was done in three patients: two with neurogenic tumors and one with a bronchogenic cyst. The tumors and cyst showed evidence of a discrete plane on computed tomography of the chest. The mean operation time and estimated blood loss were 156 min and 45 g, respectively. For all three patients, the chest drain was removed within 48 h after operation, and there were no complications related to thoracoscopic surgery. The advantages of this approach are less pain, early return to normal activity, and an acceptable cosmetic appearance. Based on our experience, thoracoscopic surgery is considered the treatment of choice for certain mediastinal tumors or cyst.

Epidermal growth factor in gastric carcinoma as a risk factor of postoperative recurrence

The expression of epidermal growth factor (EGF) was immuno-histochemically examined in the primary lesions of 201 patients with advanced gastric cancer who underwent curative resection. EGF-positive tumor cells were detected in the specimens of 75 patients (37.3%). A significant correlation was observed between the extent of lymph node metastasis and EGF expression (p < 0.01), indicating that EGF-positive cancer has a tendency to lymph node metastasis. The 2-year and 5-year survival rates of the patients with EGF-negative tumors were 77.2% and 63.0%, respectively, while those with EGF-positive tumors were 59.1% and 47.5% respectively. The difference in survival rates reached a maximum 2 years after surgery, indicating that the patients with EGF-positive gastric cancer had a higher risk of early recurrence. Therefore, the amount of EGF produced by a tumor may play some role in the growth of metastatic tumors and residual tumor cells after surgery, and thus be a potential risk factor in recurrence.

Spontaneous production of Epstein-Barr virus by B lymphoblastoid cell lines obtained from patients with Sjögren's syndrome. Possible involvement of a novel strain of Epstein-Barr virus in disease pathogenesis

OBJECTIVE

To investigate the involvement of Epstein-Barr virus (EBV) in the pathogenesis of Sjögren's syndrome (SS) and to examine whether the spontaneous production of EBV is unique to SS B cell lines.

METHODS

B cell lines were established from peripheral blood mononuclear cells (PBMC) of patients with systemic lupus erythematosus, rheumatoid arthritis, and SS. The cord blood immortalization assay, flow cytometric analysis, and polymerase chain reaction (PCR) were used to detect EBV production by B cell lines.

RESULTS

SS B cell lines produced EBV at a higher frequency, and in significantly larger amounts, than did other B cell lines. However, no correlation with the amount of EBV DNA in the genome of B cell lines was found. PCR analysis revealed that EBV with a B95-8--like U2 region was dominant in SS B cell lines.

CONCLUSION

Spontaneous, massive production of EBV by B cell lines is unique to SS, and may contribute to the polyclonal B cell activation seen in this disease.

Early squamous lung cancer and longer survival rates

The criteria for early squamous lung cancer remain open to discussion as patients who have been treated for early stage lung cancer, such as T1N0M0, and appear to have been cured clinically may die from recurrent or metastatic tumors. We reviewed the pathological data on 242 surgical patients with squamous lung cancer and found 31 cases (13%) of early lung cancer, included were early lung cancer of the hilar type as a lesion restricted to the bronchial wall without lymph node involvement, and early lung cancer of the peripheral type as a lesion of less than 2 cm and surrounded by visceral pleura but without lymph node involvement. Of 89 patients with hilar-type squamous lung cancer, 17 (19%) had early lung cancer, and 14 (9%) of 153 patients with peripheral-type squamous lung cancer had early lung cancer (p < 0.05). For early lung cancer of the hilar type, all but 1 (94%) were detected using sputum cytologic study and bronchoscopy. For early lung cancer of the peripheral type, all were detected on chest X-ray, but 57% were cytologically proven to be malignant. The 5-year survival rate for patients with early lung cancer, according to this new criteria is 90%; 92% for the hilar type and 88% for the peripheral type. Thus, classification of early squamous lung cancer is pertinent for determining the prognosis and selection of treatment. We emphasize that efforts be made to detect early lung cancer.

A 94 year old male stage IV breast cancer patient showing complete remission under tamoxifen treatment after operation

A 94 year old man with an invasive ductal carcinoma of the breast (T4N2M1, stage IV), underwent a modified radical mastectomy to improve his quality of life. The estrogen receptor status of both the breast tumor and the metastatic axillar lymph nodes was high. Immunohistochemical staining for epidermal growth factor, epidermal growth factor receptor, or c-erbB-2 protein was negative. The patient received only tamoxifen continuously for 3 months, and later apparently showed a complete remission. Therefore, in advanced male breast cancer with a high estrogen receptor status, operation in conjunction with hormone therapy may lead to a favorable result in some cases.

Purification and characterization of 3-mercaptolactic acid S-conjugate oxidases

Two enzymes catalysing the oxidative formation of 3-mercaptopyruvic acid S-conjugates from L-3-mercaptolactic acid S-conjugates were purified to apparent homogeneity from rat liver cytosol. The two enzymes, tentatively designated MLO-I and MLO-II, showed a molecular mass of 160 and 250 kDa and were composed of four and six subunits of 41 and 39 kDa, respectively. Both enzymes possessed flavin mononucleotide as prosthetic group and oxidized several aromatic and aliphatic S-substituted L-3-mercaptolactic acids as well as alpha-hydroxy acids such as L-3-phenyllactic acid and L-2-hydroxyisocaproic acid. Glycolic acid and 3-(4-hydroxyphenyl)-lactic acid were the specific substrates for MLO-I and MLO-II, respectively. Neither of the enzymes oxidized beta- and gamma-hydroxy acids such as 3- and 4-hydroxybutyric acid. 2-Hydroxyisobutyric acid, ethyl-2-hydroxybutyrate, malic acid, 1-butanol, benzyl alcohol and L-leucine did not act as substrates for the enzymes. MLO-I and MLO-II exerted their maximum activities around pH 5.5 with Km of 0.5 and 0.25 mM and Vmax of 0.9 and 0.2 mumol/min/mg, respectively, when S-(4-bromophenyl)-3-thiolactic acid was used as substrate. MLO-I was inhibited by sulphydryl-modifying agents, while MLO-II was not. Both enzymes were strongly inhibited by divalent metal ions. These results indicate that MLO-I and MLO-II are different from L-amino acid oxidase (EC 1.4.3.2), malate oxidase (EC 1.1.3.3), L-alpha-hydroxy acid oxidase (EC 1.1.3.15) and glycolate oxidase (EC 1.1.3.1). The present enzymes are likely to be involved in the formation of cysteine conjugates from L-3-mercaptolactic acid S-conjugates in conjunction with cysteine conjugate aminotransferases.