Usefulness of magnetic resonance imaging for surgical management of extravasation of an antitumor agent: a case report

We report a case of extravasation of an antitumor agent by preoperative magnetic resonance (MR) imaging. MR studies demonstrated a decreased signal intensity on T1- and T2-weighted images and a strong enhancement of contrast media in injured tissue, including subcutaneous adipose tissue and deep fascia, which was cicatrical macroscopically. The MR findings were in good agreement with the macroscopic findings. We believe that MR imaging is useful for estimating deep tissue damage due to extravasation of an antitumor agent.

Novel mechanism of photoinduced reversible phase transitions in molecule-based magnets

A novel microscopic mechanism of bidirectional structural changes is proposed for the photoinduced magnetic phase transition in Co-Fe Prussian blue analogs on the basis of ab initio quantum chemical cluster calculations. It is shown that the local potential energies of various spin states of Co are sensitive to the number of nearest neighbor Fe vacancies. As a result, the forward and backward structural changes are most readily initiated by excitation of different local regions by different photons. This mechanism suggests an effective strategy to realize photoinduced reversible phase transitions in a general system consisting of two local components.

[Three cases of primary acute pulmonary cavitation in sarcoidosis]

Sarcoidosis has a variety of pulmonary manifestations including the nodular, or infiltrative form. However, primary cavitary formation is rare. In this report, we describe three cases of sarcoidosis with primary acute pulmonary cavitations. All three patients were young adults (2 men and 1 woman) and chest radiography and chest CT showed bilateral Hilary lymphadenopathy, multiple cavitations with thin, smooth walls, and diffuse granular shadows. Primary acute pulmonary cavitation of sarcoidosis was diagnosed, since a transbronchial biopsy specimen revealed sarcoid granuloma, and there was no evidence of infection, emphysematous change, or fibrotic or cystic bronchiectatic changes on chest radiography in any case. Corticosteroid therapy was given in all cases for severe extrathoracic disease (2 of severe uveitis and 1 of CNS involvement). After the treatment, the multiple cavities and diffuse granular shadows in the lung fields disappeared. We accordingly suggest that corticosteroid therapy is effective for primary acute cavitation in sarcoidosis.

Expression of inducible nitric oxide synthase and Fas/Fas ligand correlates with the incidence of apoptotic cell death in atheromatous plaques of human coronary arteries

It was recently reported that inducible nitric oxide synthase was expressed in advanced atheromatous plaques. So we investigated the effect of NO or peroxynitrite reactive product of NO or O(2)(-) released by iNOS induced in macrophages or T lymphocytes on inflammatory cells in atheromatous plaques of human coronary arteries by immunohistochemistry. We found that iNOS was expressed in T lymphocytes and macrophages in T lymphocytes and macrophages coexisted advanced atheromatous areas. Most of the smooth muscle cells are not coexisted with T lymphocytes. We could not find iNOS in those smooth muscle cells. Only a small number of iNOS-positive smooth muscle cells were found close to T lymphocytes and macrophages. Markers for apoptotic cells induced in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) showed that many apoptotic T lymphocytes and macrophages existed near iNOS induced cells. Fas and Fas ligand were expressed in almost same areas that iNOS was expressed. By double-label immunostaining, Fas was expressed in T lymphocytes but Fas ligand was expressed in macrophages and in some T lymphocytes. These results suggest that NO from iNOS induces Fas and Fas ligand-mediated apoptosis and associates with regression of atherosclerosis. On the other hand, nitrotyrosine was detected wider areas than iNOS. So peroxynitrite from iNOS damages cells and tissues widely and may associate with progression of atherosclerosis. These results suggest an important role of iNOS in mediating both regressive changes and progressive change in atheromatous plaques.

Intermolecular cross-linking between the periplasmic Loop3-4 regions of PomA, a component of the Na+-driven flagellar motor of Vibrio alginolyticus

PomA and PomB form a complex that conducts sodium ions and generates the torque for the Na(+)-driven polar flagellar motor of Vibrio alginolyticus. PomA has four transmembrane segments. One periplasmic loop (loop(1-2)) connects segments 1 and 2, and another (loop(3-4)), in which cysteine-scanning mutagenesis had been carried out, connects segments 3 and 4. When PomA with an introduced Cys residue (Cys-PomA) in the C-terminal periplasmic loop (loop(3-4)) was examined without exposure to a reducing reagent, a 43-kDa band was observed, whereas only a 25-kDa band, which corresponds to monomeric PomA, was observed under reducing conditions. The intensity of the 43-kDa band was enhanced in most mutants by the oxidizing reagent CuCl(2). The 43-kDa band was strongest in the P172C mutant. The motility of the P172C mutant was severely reduced, and P172C showed a dominant-negative effect, whereas substitution of Pro with Ala, Ile, or Ser at this position did not affect motility. In the presence of DTT, the ability to swim was partially restored, and the amount of 43-kDa protein was reduced. These results suggest that the disulfide cross-link disturbs the function of PomA. When the mutated Cys residue was modified with N-ethylmaleimide, only the 25-kDa PomA band was labeled, demonstrating that the 43-kDa form is a cross-linked homodimer and suggesting that the loops(3-4) of adjacent subunits of PomA are close to each other in the assembled motor. We propose that this loop region is important for dimer formation and motor function.

Emergence of oscillations in a model of weakly coupled two Bonhoeffer-van der Pol equations

Bifurcations of periodic solutions in a model of weakly coupled two Bonhoeffer-van der Pol equations are studied. The model realizes a half-center model with reciprocal inhibition, a typical model used in the field of neural motor control to account for the generation of alternating rhythmic bursts observed in motoneurons and spinal neural networks. Several oscillatory solutions such as in-phase, anti-phase as well as out-of-phase solutions emerge from the model's equilibrium as one of the parameters of the model changes. Among the variety of bifurcations exhibited by the model, we analyze Hopf bifurcations, by which several periodic solutions emerge, and illustrate generation mechanisms of alternating oscillations in the model.

[A case of anaphylaxic shock due to latex glove used on internal examination and on the probe of intrauterine echogram]

A 15 year old female with uterus bicornis bicollis was admitted for operation. She had a history of atopic dermatitis and allergy to buckwheat, raw egg and latex. Two months previously she had developed whole body flushing during dental treatment, and latex glove used by the dentist had been suspected as the cause. Prior to the operation she underwent internal examination and intrauterine echogram in which a latex glove was carelessly used by another gynecologist who had not confirmed her past history. After 30 minutes, dyspnea and urticaria without itching, appeared suddenly. Blood pressure decreased to 80/50 mmHg and heart rate increased to 120 beats.min-1. She was then transferred to our ICU. Methylprednisolone was administered intravenously for dyspnea and circulatory collapse. After 3 hours, the patient made an uneventful recovery. The increased plasma latex protein-specific IgE levels confirmed anaphylaxis to latex. The increasing incidence of potentially life-threatening allergic reactions to latex has caused mounting concern over recent years. We may suspect latex allergy when an anaphylaxic reaction or shock of unknown origin occurs. In hospitals, latex free products must be prepared for use with latex allergic patients and for protection of medical staff with this allergy.

Immunobiological activities of a chemically synthesized lipid A of Porphyromonas gingivalis

A synthetic lipid A of Porphyromonas gingivalis strain 381 (compound PG-381), which is similar to its natural lipid A, demonstrated no or very low endotoxic activities as compared to Escherichia coli-type synthetic lipid A (compound 506). On the other hand, compound PG-381 had stronger hemagglutinating activities on rabbit erythrocytes than compound 506. Compound PG-381 also induced mitogenic responses in spleen cells from lipopolysaccharide (LPS)-hyporesponsive C3H/HeJ mice, as well as LPS-responsive C3H/HeN mice. The addition of polymyxin B resulted in the inhibition of mitogenic activities, however, compound 506 did not show these capacities. Additionally, compound PG-381 showed a lower level of activity in inducing cytokine production in peritoneal macrophages and gingival fibroblasts from C3H/HeN mice, but not C3H/HeJ mice, in comparison to compound 506. Thus, this study demonstrates that the chemical synthesis of lipid A, mimicking the natural lipid A portion of LPS from P. gingivalis, confirms its low endotoxic potency and immunobiological activity.

Optimization of the formulation and characterization of the physicochemical properties of the novel platelet-activating factor receptor antagonist E5880

The injectable formulation of E5880, a novel platelet-activating factor (PAF) receptor antagonist, was determined from the study of pH stability, the selection of excipient, and the relationship between moisture and stability. The physicochemical properties of E5880 in the optimized formulation (0.6 mg/ml of E5880, 0.1% [4.8 mM] citric acid, 10% lactose, pH 2.8) were characterized. The critical micelle concentration of E5880 in the buffer was 0.1 mg/ml, and the structure was of spherical micelles. The micellar size was 5.6 nm and did not change before and after lyophilization and storage. The number of the molecules per micelle was 40. The micropolarity around the hydrocarbon region of the micelle was similar to that of butanol.

The effect of lipid A analog E5531 on membrane properties of dipalmitoylphosphatidylcholine

The effect of the lipid A analog E5531 on the phospholipid membrane was determined and compared with that of the lipid A from Escherichia coli (EC). E5531 decreased the phase transition temperature of dipalmitoylphosphatidylcholine (DPPC) membrane and increased the fluidity and permeability. On the other hand, EC increased the phase transition temperature and decreased the membrane fluidity and permeability. These results suggest that the reason for the difference of biological effects of E5531 and lipid A from EC would be caused by the differences from the effect on the cell membranes.

Coupling ion specificity of chimeras between H(+)- and Na(+)-driven motor proteins, MotB and PomB, in Vibrio polar flagella

We have shown that a hybrid motor consisting of proton-type Rhodobacter sphaeroides MotA and sodium-type VIBRIO: alginolyticus PomB, MotX and MotY, can work as a sodium-driven motor in VIBRIO: cells. In this study, we tried to substitute the B subunits, which contain a putative ion-binding site in the transmembrane region. Rhodobacter sphaeroides MotB did not work with either MotA or PomA in Vibrio cells. Therefore, we constructed chimeric proteins (MomB), which had N-terminal MotB and C-terminal PomB. MomB proteins, with the entire transmembrane region derived from the H(+)-type MotB, gave rise to an Na(+) motor with MotA. The other two MomB proteins, in which the junction sites were within the transmembrane region, also formed Na(+) motors with PomA, but were changed for Na(+) or Li(+) specificity. These results show that the channel part consisting of the transmembrane regions from the A and B subunits can interchange Na(+)- and H(+)-type subunits and this can affect the ion specificity. This is the first report to have changed the specificity of the coupling ions in a bacterial flagellar motor.

Formation of spherical micelles by the novel platelet activating factor receptor antagonist, E5880

E5880, a novel platelet activating factor receptor antagonist, was dispersed in water for the preparation of injectable formulation and the physicochemical properties of the micelles were characterized. The critical concentration for formation of micelles was 0.12 mM. Using the area per molecule results, the critical packing parameter was calculated and showed that the structure was composed of spherical micelles and the number of the molecules per micelle was 88. The diameter of a micelle was 8.1 nm. The fluidity and micropolarity around the hydrocarbon region of the micelles were evaluated and compared to the surfactants, stearyltrimethylammmonium chloride and cetyltrimethylammonium chloride.

A slow-motility phenotype caused by substitutions at residue Asp31 in the PomA channel component of a sodium-driven flagellar motor

PomA is thought to be a component of the ion channel in the sodium-driven polar-flagellar motor of Vibrio alginolyticus. We have found that some cysteine substitutions in the periplasmic region of PomA result in a slow-motility phenotype, in which swarming and swimming speeds are reduced even in the presence of high concentrations of NaCl. Most of the mutants showed a sodium ion dependence similar to that of the wild type but with significantly reduced motility at all sodium ion concentrations. By contrast, motility of the D31C mutant showed a sharp dependence on NaCl concentration, with a threshold at 38 mM. The motor of the D31C mutant rotates stably, as monitored by laser dark-field microscopy, suggesting that the mutant PomA protein is assembled normally into the motor complex. Mutational studies of Asp31 suggest that, although this residue is not essential for motor rotation, a negative charge at this position contributes to optimal speed and/or efficiency of the motor.

Physiological concentration of 17beta-estradiol retards the progression of severe atherosclerosis induced by a high-cholesterol diet plus balloon catheter injury: role of NO

The molecular mechanisms of the antiatherosclerotic effects of estrogen are not yet known. We evaluated the effects of 17beta-estradiol (E(2)) on high cholesterol diet- (HCD; standard diet and 1% cholesterol) and balloon injury-induced atherosclerosis in female New Zealand White rabbits. The abdominal aortas of 40 oophorectomized (Groups 1 through 5) and 8 nonoophorectomized (Group 6) rabbits were injured by balloon catheter, and the animals were then divided into the following groups and treated for 10 weeks: Group 1, standard diet; Group 2, standard diet plus a moderate dose of E(2) (100 microg x kg(-1) x d(-1)); Group 3, HCD; Group 4, HCD plus a moderate dose of E(2); Group 5, HCD plus a low dose of E(2) (20 microg x kg(-1) x d(-1)); and Group 6, HCD in nonoophorectomized rabbits. After the treatment phase, plasma E(2) was increased up to 282.2+/-45.5 pg/mL in Group 2, 263.0+/-41.5 pg/mL in Group 4, 87. 9+/-18.8 pg/mL in Group 5, and 45.6+/-7.3 pg/mL in Group 6. HCD-mediated increases in plasma lipid levels were not changed by E(2) treatment, whereas E(2) decreased the aortic intimal thickening in Group 2 animals compared with those in Group 1 and reduced atherosclerosis in the thoracic and abdominal aortas of Group 4, 5, and 6 rabbits compared with those in Group 3. E(2) restored the impaired abdominal aortic endothelium-dependent relaxation of balloon-injured and HCD-supplemented rabbits, and E(2) increased basal nitric oxide (NO) release. The basal NO-releasing effect showed a significant, inverse relation with the severity of atherosclerosis. Plasma E(2) concentration also showed a significant, inverse relation with atherosclerotic area. In conclusion, physiological concentrations of E(2) can retard the progression of severe atherosclerosis and stabilize atheromas induced by HCD and balloon injury. The retardation may be partially mediated by endothelial NO function in vessels treated with E(2).

Characterization of the physicochemical properties of the micelles of platelet-activating factor (C18:0)

The purpose of this study was to clarify the physicochemical properties of the micelles of platelet-activating factor (PAF; C18:0). The critical micelle concentration (CMC) of PAF (C18:0) was determined (0.20 microM) using fluorescence techniques. The fluidity and the micropolarity of the PAF (C18:0) micelle were similar to those of the micelle of stearoyl lysophosphatidylcholine.

Regulation by intracellular glutathione of TNF-alpha-induced p38 MAP kinase activation and RANTES production by human pulmonary vascular endothelial cells

BACKGROUND

We have previously shown that p38 mitogen-activated protein (MAP) kinase regulates tumor necrosis factor-alpha (TNF-alpha)-induced RANTES production by human pulmonary vascular endothelial cells, and that sensitivity to TNF-alpha is inversely correlated with cellular reduction and oxidation (redox) state. However, a regulatory role of intracellular glutathione (GSH) in TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production has not been determined. In the present study, therefore, we extended our previous studies and focused on redox regulation on p38 MAP kinase activation.

METHODS

Human pulmonary vascular endothelial cells were exposed to N-acetylcysteine (NAC) or buthionine sulfoximine (BSO), and then TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production were determined.

RESULTS

The results showed that 1) NAC attenuated TNF-alpha-induced p38MAP kinase activation and RANTES production 2) SB 203580 as the specific inhibitor of p38 MAP kinase activity attenuated TNF-alpha-induced RANTES production 3) BSO facilitated TNF-alpha-induced p38 MAP kinase activation and RANTES production 4) SB 203580 attenuated BSO-mediated facilitation of TNF-alpha-induced RANTES production.

CONCLUSIONS

These results indicated that TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human pulmonary vascular endothelial cells are inversely regulated by intracellular GSH levels.

Selective inhibitor of p38 mitogen-activated protein kinase inhibits lipopolysaccharide-induced interleukin-8 expression in human pulmonary vascular endothelial cells

Adult respiratory distress syndrome (ARDS) characterized by permeability edema is observed in severe insults such as bacteremia sepsis. Interleukin (IL)-8, which chemoattracts and activates neutrophils, has been suggested to play an important role in the production of ARDS. Therefore, the inhibition of IL-8 production is an important strategy for the treatment of ARDS. Recent studies have revealed the role of p38 mitogen-activated protein (MAP) kinase in cytokine expression and the inhibition by a selective inhibitor of p38 MAP kinase activity of cytokine expression in a variety of cell types. However, little is known about the role of p38 MAP kinase in lipopolysaccharide (LPS)-induced IL-8 expression in pulmonary vascular endothelial cells and the effect of a selective p38 MAP kinase inhibitor on it. In the present study, we therefore attempted to clarify these issues. The results showed that LPS induced p38 MAP kinase phosphorylation and activity, and SB 203580 as a selective inhibitor of p38 MAP kinase activity inhibited p38 MAP kinase activity and IL-8 expression in LPS-stimulated pulmonary vascular endothelial cells. These results indicate that p38 MAP kinase regulates LPS-induced IL-8 expression in pulmonary vascular endothelial cells. Although it is currently not known whether SB 203580 is capable of producing beneficial effects on ARDS, a strategy of inhibiting p38 MAP kinase activity by a selective p38 MAP kinase inhibitor may apply to the therapy for ARDS.

Characterization of the physicochemical properties of the micelles by the novel platelet activating factor receptor antagonist E5880

E5880, a novel platelet activating factor receptor antagonist, was dispersed in the buffer solution (4.8 mM citric acid, 10% lactose, pH 2.8) for the preparation of an injectable formulation and the physicochemical properties of the micelles were characterized. The critical micelle concentration of E5880 was 0.12 mM. Using the area per molecule results, the critical packing parameter was calculated and showed that the structure was spherical and the number of molecules in the aggregates was 46. The diameter of the micelle was 5.6 nm. The micropolarity around the hydrocarbon region of the micelle was similar to that of isobutanol.

Eating habits and intensity of medication in elderly hypertensive outpatients

Several dietary factors have been shown to lower blood pressure in elderly patients in clinical trials, but it is not known how eating habits affect blood pressure control in outpatients treated with antihypertensive drugs. We obtained data on dietary information regarding food groups rich in potassium, magnesium, and calcium by submitting a questionnaire to 190 elderly outpatients. Blood pressure levels and the intensity and cost of antihypertensive treatment were obtained from clinical records. The mean age and blood pressure were 72.3 +/- 9.3 years and 138.7 +/- 15.2/74.6 +/- 8.8 mmHg, respectively. Patients were divided into three groups on the basis of the intensity of medication: the LS group (n=52), treated with a low dose of a single drug; the HS group (n=95), treated with a high dose of a single drug; and the M group (n=43), treated with multiple drugs. Average age, body mass index, blood pressure levels, and extent of target organ damage were similar among the three groups. Intake frequency (rarely, once or twice per week, 3 to 6 times per week, or every day) of the food groups was compared among the three groups. The LS group ate fruit (p < 0.05) and seaweed (p < 0.01) with significant frequency compared with the other groups, whereas milk and dairy products were taken with similar frequency by all groups. The monthly cost of antihypertensive medications averaged 17,218 +/- 620 yen in the LS group, 17,746 +/- 375 yen in the HS group, and 20,066 +/- 1,364 yen in the M group. These data suggest that habitual intake of foods rich in potassium and magnesium are associated with reduced intensity and cost of medication and with preservation of blood pressure control in elderly hypertensive outpatients.

A temperature study on critical micellization concentration of the novel platelet-activating factor receptor antagonist E5880 in water by electric conductivity measurements

To clarify the behavior of the novel platelet-activating factor (PAF) receptor antagonist E5880 in aqueous solution, electric conductivity was measured at different temperatures (every 5 degrees C), ranging from 15 degrees C to 50 degrees C. Critical micellization concentration (CMC) of E5880 was dependent on the temperature; at 30 degrees C, the CMC value was smallest (0.143 mM). Below that temperature, the enthalpy for formation of the micelle (delta Hm0) was positive, and the formation of micelles was endothermic; above that temperature, delta Hm0 was negative, and the formation of micelles was exothermic.

The effect of the membrane fluidity on pharmacokinetics for lipid A analog E5531

The effect of the dispersing procedure on the aggregate size, membrane fluidity and the pharmacokinetics were evaluated for the lipid A analog E5531. The size of the aggregates prepared by the pH-jump method (pH 11.0-->7.3) was decreased, reaching 20 nm with increasing dispersing time in 0.003 N NaOH (pH 11.0). The membrane fluidity of the aggregates increased with increasing dispersing time. When prepared by the normal dilution method (pH 7.3-->7.3), the size of the aggregates remained constant at 150 nm and the membrane fluidity was smaller compared to samples prepared by the pH-jump method. Using samples with different degrees of hydration and different membrane fluidities prepared by the pH-jump method, the pharmacokinetics after intravenous administration into rats were evaluated, and the data obtained confirmed that the membrane fluidity was correlated with the pharmacokinetics in rat. In addition, E5531 vials were stable for 24 months at room temperature when used within 24 hr after reconstitution.

[Blood pressure measurement by primary care physicians: comparison with the standard method]

OBJECT

To examine the usual methods of blood pressure (BP) measurement by primary care physicians and to compare them with the standard methods.

METHOD

DESIGN

Cross-sectional survey by self-administered questionnaire.

SUBJECTS

Primary care physicians who graduated from Jichi Medical School and were working at clinics. Each standard method for 20 items was defined as the one that was most frequently recommended by 6 guidelines (USA 3, UK 1, Canada 1, Japan 1) and a recent comprehensive review about BP measurement.

RESULTS

Of 333 physicians, 190 (58%) responded (median age 33, range 26 to 45 years). Standard methods and percentages of physicians who follow them are: [BP measurement, 17 items] supported arm 96%; measurement to 2 mmHg 91%; sitting position 86%; mercury sphygmomanometer 83%; waiting > or = 1 minute between readings 58%; palpation to assess systolic BP before auscultation 57%; check accuracy of home BP monitor 56%; Korotkoff Phase V for diastolic BP 51%; bilateral measurements on initial visit 44%; small cuff available 41%; > or = 2 readings in patients with atrial fibrillation 38%; > or = 2 readings on one visit 20%; cuff deflation rate of 2 mmHg/pulse 14%; large cuff available 13%; check accuracy of monitor used for home visit 8%; waiting time > or = 5 minute 3%; readings from the arm with the higher BP 1%. [Knowledge about BP monitor, 2 items] appropriate size bladder: length 11%; width 11%. [Check of sphygmomanometer for leakage, inflate to 200 mmHg then close valve for 1 minute] leakage < 2 mmHg 6%; median 10 (range 0-200) mmHg. Average percentage of all 20 items was 39%. Number of methods physicians follow as standard: median 8 (range 4 to 15) and this number did not correlate with any background characteristics of the physicians. Furthermore, we also obtained information on methods not compared with the standard. Fifty-four percentage of physicians used more standard methods in deciding the start or change of treatment than in measuring BP of patients with good control. About 80% of physicians use home BP readings in diagnosis or treatment of hypertension, but about half of physicians with ambulatory BP monitors use their measured readings.

CONCLUSION

Primary care physicians used various techniques for routine BP measurement and no physician completely followed the standard. Such measurements may affect the diagnosis and treatment of hypertension, but measuring all BPs solely by the standard is not practical. We need to have a practical and efficient method of BP measurement for routine practice in the primary care setting.

In vivo imaging of adenovirus-mediated over-expression of dopamine D2 receptors in rat striatum by positron emission tomography

PET was used to provide in vivo imaging of the over-expression of dopamine D2 receptor (D2R) induced by adenovirus vector-mediated gene transfer in rat striatum. The uptake of three kinds of D2R-specific ligands, [11C]raclopride, [11C]nemonapride and [11C]N-methylspiperone, measured by PET was higher in the striatum injected with the vectors for D2R than the contralateral striatum injected with a control vector 2-3 days after injection. However, the uptake of [11C]SCH 23390, a dopamine D1 receptor specific ligand, or [11C]beta-CIT-FP, a dopamine transporter specific tracer, was not different between bilateral striata. Co-injection of excess unlabeled raclopride inhibited the uptake of [11C]raclopride. At day 16 the increased uptake of [11C]raclopride declined to basal level, consistent with past in vitro assessment of this vector. In vivo imaging of D2R will permit longitudinal assessment of the efficiency of this and similar vectors in rat brain that can be related to functional changes being observed.

Lympholeukemia in madai Pagrus major in Japan

Lympholeukemia has been occurring to an epizootic extent with mass mortality in 1 and 2 yr old madai (= Japanese red sea bream) Pagrus major in the winter season (October-May) in the western regions of Japan since 1975. Diseased fish displayed severe anemia and markedly increased numbers of neoplastic lymphocytoid and lymphoblastoid cells in the blood. Neoplastic cells originated in the splenic lymphatic cells and systemically caused severe metastatic lesions in the heart, liver, kidney, digestive tracts, gills and the lateral musculature. Electron microscopy revealed adeno-like viral particles (78 to 83 nm in diameter) in the nucleus of lymphoblastoid cells which appeared in the early prevalent stage but no viral particles in the lymphocytoid cells or plasmacytoid cells, which subsequently increased in number. In this paper, we describe light and electron microscopic features of neoplasms and neoplastic cells.