Evaluation of mRNAs encoding muscarinic receptor subtypes in human detrusor muscle

PURPOSE

The present study evaluated the muscarinic receptor subtypes corresponding to m1 to m5 genes in human detrusor muscle.

MATERIALS AND METHODS

The mRNAs encoding m2 and m3 subtypes were assessed by reverse transcription (RT)-polymerase chain reaction (PCR). The amounts of cDNA synthesized from m2 and m3 mRNAs were measured by using subcloned plasmid DNAs. The distribution of m2 and m3 mRNAs in detrusor was estimated by comparing the amount of m2 cDNA with that of m3 cDNA.

RESULTS

The m2 mRNA:m3 mRNA ratio was 1.06:1.00 in human detrusor. In the cryostat sections of human detrusor, the presence of both m2 and m3 mRNAs was confirmed by in situ hybridization. However, the RT-PCR products derived from m1, m4 and m5 subtype mRNAs were not detected.

CONCLUSION

These results suggest that human detrusor muscle coexpresses muscarinic m2 and m3 receptors and that the populations of the 2 subtypes are not significantly different.

Isolation of a new superantigen with potent mitogenic activity to murine T cells from Streptococcus pyogenes

A mitogenic substance on murine lymphocytes was detected in the culture supernate of Streptococcus pyogenes type 12 strain. This substance had a molecular weight of 28,000 and pI 9.2, and was designated as S. pyogenes mitogen (SPM). The proliferative response of C3H/HeN spleen cells began at 1 ng ml-1 and reached a maximal response at 100 ng ml-1 of SPM for 4 days culture. Anti-Thy 1.2 mAb and complement-treated spleen cells abrogated the proliferative response to any dose of SPM. Although the anti-major histocompatibility complex class 1 mAbs had no blocking effect on proliferation by SPM, this proliferation was substantially inhibited by the addition of either anti-I-A or anti-I-E mAb, and complete inhibition was produced by the addition of both mAbs. Fixed antigen-presenting cells still induced T cell proliferation by SPM. A significant expansion of T cells bearing V beta 13 T-cell receptor was observed up to 73% among the Thy 1.2+ cells in cultures stimulated with SPM, indicating expansion in a V beta-specific manner. Immunoblotting of IEF-separated proteins showed that anti-streptococcal pyrogenic exotoxin (SPE) C reacted with a protein of pI 6.9 and anti-SPEB did not show any reactivity. SPEA was reported to expand V beta 8.1 and 8.2 bearing murine T cells, and SPM did not. SPM also exhibited potent mitogenic activity on human T cells and V beta 21+ T cells were selectively expanded. These results lead to the conclusion that SPM was neither SPEA, B nor C, but a new protein belonging to a group of streptococcal superantigens with activity on not only human but also murine lymphocytes.

[Constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II)]

We experienced a case of constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II). The patient complained of orthopnea and leg edema. The cause of constrictive pericarditis was pericardial effusion due to dissecting aortic aneurysm. Ascending aortic replacement with graft and decortication of thickened pericardium were performed. We confirmed the decrease of CVP and PAP intraoperatively. Postoperative course was uneventful.

Sustained ventricular tachycardias associated with myotonic dystrophy

Patients with myotonic dystrophy are reported to have a higher frequency of sudden death than the general population. Although causes of sudden death in myotonic dystrophy are suggested to be due to conduction of defects progressing, the HV interval cannot predict whether conduction system disease would develop or progress. We report two cases of myotonic dystrophy complicated with sustained monomorphic ventricular tachycardias (VT), which can cause sudden death. In Case No. 1, although the patient was treated successfully for sustained VT with verapamil in electrophysiologic studies, another sustained VT was confirmed 2 years later. In Case No. 2, the patient showed decreased left ventricular ejection fraction and late potentials, and induced sustained VT that was identical to clinically documented VT. Although VT is believed to be rare in patients with myotonic dystrophy, these cases suggest that VT is a possible cause of sudden death.

[Autoimmune hemolytic anemia with eosinophilia in elderly patient]

A 70-year-old woman was admitted to our hospital in November 1992 for evaluation of anemia. Physical examination revealed anemia, jaundice, swelling of axial and inguinal lymph nodes, and splenomegaly. Abnormal hematological findings were as follows: Hb of 3.9 g/dl, reticulocyte count of 58.2% (61.7 x 10(4)/microliters), hyperplasia of normal erythroblasts in bone marrow, and eosinophilia (21.0%, 2352/microliters) in peripheral blood. Routine laboratory examinations revealed polycolonal hypergammaglobulinemia 3.0 g/dl, a high level of serum LDH (797 IU/I) and a total bilirubin of 2.4 mg/dl (indirect, 1.6 mg/dl). The serum haptoglobin level was very low (< 5 mg/dl). Results of serological examinations were as follows: IgG of 3366 mg/dl, CH50 of 16.0 U/ml, positive Coombs test 2+, and positive tests for antinuclear antibody, rheumatoid factor, and cold agglutinin. CRP was negative. PHA-stimulated lymphocyte blast formation, NK activity, and ADCC activity were found to be suppressed, and the percentage of CD4-positive lymphocytes in peripheral blood was also low. An axillary lymph node biopsy revealed reactive lymphadenitis. No signs or history suggested allergy, collagen disease, or parasitic infection. Autoimmune hemolytic anemia (AIHA) complicated by immunologic abnormalities and eosinophilia was diagnosed. Oral prednisolone markedly reduced the hemolytic anemia, eosinophilia, lymph node swelling, and splenomegaly, but NK activity remained low.

Prognostication of proximal femoral growth disturbance after Perthes' disease

Disturbance of proximal femoral growth associated with Perthes' disease was investigated retrospectively with the use of serial radiographs of 48 patients with unilaterally affected hips. Two types of proximal femoral growth abnormalities--moderately disturbed (6 patients) and severely disturbed (13 patients)--were observed and classified based on resultant femoral length shortening and femoral head deformity of affected hips. Proximal femoral growth disturbance after Perthes' disease was dependent on age at clinical onset: patients whose age at onset was greater than 8 years had a poor prognosis. Future femoral length shortening and femoral head deformity were also found to correlate with the extent of epiphyseal and physeal involvements and the acetabular coverage of the femoral head at the stage of regeneration of involved epiphysis. The current results raised the possibility that the severity of proximal femoral growth disturbance and abnormal growth patterns could be prognosticated based on the extent of epiphyseal and physeal involvements and on the lateralization of femoral head estimated on radiographs during the early stages of Perthes' disease.

Metabolism, uptake, and transepithelial transport of the diastereomers of Val-Val in the human intestinal cell line, Caco-2

PURPOSE

The purpose of this study was to determine whether the binding of the diastereomers of Val-Val to the apical oligopeptide transporter(s) could be correlated with their cellular uptake and transepithelial transport.

METHODS

The Caco-2 cell culture system was used for all experiments. The binding of the diastereomers of Val-Val was evaluated by determining their ability to inhibit [3H]cephalexin uptake. The stability of the diastereomers was determined in a homogenate of Caco-2 cells and in the apical bathing solution over Caco-2 cell monolayers. The cellular uptake and transepithelial transport properties of the individual diastereomers were studied using Caco-2 cell monolayers.

RESULTS

10 mM concentrations of L-Val-L-Val, L-Val-D-Val, D-Val-L-Val and D-Val-D-Val inhibited cellular uptake of [3H]cephalexin (0.1 mM) by 92%, 37%, 70%, and 18%, respectively. When the cellular uptake of Val-Val diastereomers (1 mM) were evaluated, the intracellular concentrations of L-Val-D-Val and D-Val-L-Val were 15 and 50 times higher, respectively, than that of D-Val-D-Val. The cellular uptake of L-Val-D-Val and D-Val-L-Val was inhibited by Gly-Pro (10 mM) ( > 95%), whereas Gly-Pro had no effect on the cellular uptake of D-Val-D-Val. L-Val-L-Val was not detected in the Caco-2 cells, probably due to its metabolic lability. When the transepithelial transport of the Val-Val diastereomers (1 mM) was determined, L-Val-D-Val, D-Val-L-Val and D-Val-D-Val transport rates were similar. The transepithelial transport of L-Val-D-Val and D-Val-L-Val was inhibited by Gly-Pro (10 mM) 36% and 30%, respectively, while Gly-Pro inhibited carnosine (1 mM) transepithelial transport by 65%. Gly-Pro had no effect on the transepithelial transport of D-Val-D-Val.

CONCLUSIONS

These results suggest that the major transepithelial transport route of L-Val-D-Val, D-Val-L-Val and D-Val-D-Val is passive diffusion via the paracellular route. The binding of Val-Val diastereomers to the oligopeptide transporter(s) is a good predictor of their cellular uptake, however, the binding is not a good predictor of their transepithelial transport. It appears that the stereochemical requirements for the transporter that mediates efflux of the peptide across the basolateral membrane may be different from the requirements for the apical transporter that mediates cellular uptake.

Inhibition of platelet aggregation by endocardial endothelial cells

We assessed the anti-platelet properties of endocardial endothelial cells (EECs) by measuring platelet aggregation after brief interaction with EECs isolated from the right ventricles of porcine hearts. Platelet aggregation in response to thrombin was significantly inhibited by brief incubation of platelet suspensions over EEC monolayers. Pretreatment of EECs with indomethacin restored platelet reaction but that with L-NAME and hemoglobin (Hb) did not. The PGI2 content of platelet suspensions after interaction with cultured EECs was significantly correlated with the inhibition of platelet aggregation. These results suggest that EECs inhibit platelet aggregation by releasing PGI2.

[Pathology of infective endocarditis]

Clinico-pathological studies were made of 40 patients with infective endocarditis : 34 (22 men, 12 women ; ages, 5-71 years, mean, 40.4 years) had native valve endocarditis (NVE) and 6 (3 men, 3 women ; ages, 26-48 years, mean, 38.3 years) had prosthetic valve endocarditis (PVE). The aortic valve was involved most frequently (AV : 16, MV : 6, AV+MV : 8, TV : 3, MV+TV : 1). Thirteen patients had preexsisting heart disease (rheumatic in 4, floppy in 6, other in 3). Six of 21 "normal" valves showed myxomatous changes with connective tissue degradation, findings compatible with the histological diagnosis of floppy valve. The infecting organisms were identified by blood cultures in 26 patients. Bacteria and/or fungi were found histologically in 23 valves, even in those in which cultures of excised tissues were negative. In 2 cases, fungi were identified in the sewing ring of the prosthetic valves. This study demonstrates that : 1) floppy valve is a most important underlying heart disease in NVE ; 2) the infecting organisms are frequently identified histologically, even when cultures of excised tissues are negative ; and 3) fungi are important causes of both NVE and PVE, especially in patients given intensive antibiotic therapy.

Evaluation of L-pyrrolidonyl peptidase paper strip test for differentiation of members of the family Enterobacteriaceae, particularly Salmonella spp

The L-pyrrolidonyl peptidase activities of 1,033 strains of the family Enterobacteriaceae were investigated by the paper strip method to evaluate their usefulness for screening those organisms, especially Salmonella cultures. We also evaluated the usefulness of indole and tryptophan deaminase paper strip tests as supplements to the L-pyrrolidonyl peptidase test for the rapid identification of Salmonella cultures. The paper strip tests are simple, and the results are obtainable within 10 min.

Correlation of age-adjusted incidence and age-adjusted death rate in colorectal cancer among municipalities in Aomori Prefecture

To clarify to what extent death rate reflects the incidence of colorectal cancer, we calculated the age-adjusted death rates for colorectal cancer among municipalities in Aomori Prefecture for the period between 1983 and 1987, and examined the correlation with the age-adjusted incidences of the disease during different 5-year periods. In males, the age-adjusted death rate of rectal or colon cancer most correlated with the age-adjusted incidence in the preceding period by three or two years, respectively; however in females, the age-adjusted death rate best reflected the age-adjusted incidence of the same period. In males, significant correlation was lost if the interval exceeded seven years in both rectal and colon carcinomas. In females, the correlation became insignificant after an interval of four and five years in rectal and colon cancers, respectively.

[Risk of second primary cancer in two-year survivors of small cell lung cancer]

A total of 498 patients with small cell lung cancer received chemotherapy with or without chest irradiation at Osaka Prefectural Habikino Hospital from October 1977 through December 1991. Sixty-one who survived for more than two years were evaluated to determine the incidence and anatomic patterns of redevelopment of small cell lung cancer and development of second primary cancers. The numbers of expected cancers were estimated by cumulating person years of observation from 2 years after the start of treatment for small cell lung cancer to the date of death. Second primary cancers were observed in seven patients (four cases of non-small cell lung cancer, two of gastric cancer, and one of prostate cancer). The risk of a second primary cancer was 3.2 times greater than in the general population (95% Cl: 1.3-6.6). the relations between occurrence of a second primary cancer and family history of cancer, smoking history, smoking cessation after treatment of small cell lung cancer, and thoracic irradiation were studied. Occurrence of a second primary cancer correlated with family history (relative risk 7.5, 95% Cl: 1.5-22) and smoking cessation (relative risk 3.2, 95% Cl: 1.2-6.9). Long-term survivors were more likely to have a second primary cancer than a relapse of small cell lung cancer. Therefore, long-term survivors should be closely monitored for second primary cancers. Meta-analyses of studies done at several institutions may provide more detailed information on the occurrence of second primary cancers after small cell lung cancer.

Immunohistological features of basement membrane formation of uterine cervical epithelium

The state of the basement membrane (BM) was investigated in the normal epithelium, dysplasia/carcinoma in situ (CIS) and invasive carcinoma of the uterine cervix as well as metastatic lymph nodes by performing immunohistological staining for the presence of laminin (LN) and type IV collagen (CIV) and periodic acid-methenamine silver (PAM) staining of the BM. Moreover, to clarify the relationship between the epithelial cells and the BM, simultaneous staining for proliferating cell nuclear antigen (PCNA) was performed on the repaired tissue after punch biopsy. In the normal tissues, positive linear staining was observed beneath the epithelium with both PAM staining and LN.C IV staining. Some of the cases of dysplasia/CIS were continuously positive with PAM staining. However, there were sites which showed weakening and disruption of the continuity of positive staining for LN and C IV. As a function of the histological type of invasive carcinoma, the intensity of staining for LN and C IV decreased in the order of keratinizing (K), large cell non-keratinizing (LNK) and small cell non-keratinizing (SNK) histological types. However, no correlation was found between the stage of the carcinoma and the intensity of staining. In addition, the staining of the metastatic lymph nodes was similar to that of the primary lesion, and cancer foci that were in direct contact with lymphocytes were also stained for LN and C IV. During the process of reformation of the BM, LN and C IV were already present at the time when the epithelial interstitium was still negative for PAM staining. Moreover, at the time when the epithelial basal cells were PCNA-positive, LN and C IV could not be detected, and, conversely, when PCNA was negative, LN and C IV were detected. The BM is a structure which is formed when the interstitium is in a static state, and it was surmised that the production of LN and C IV is carried out by epithelial cells, including cancerous cells. Furthermore, it was surmised that the BM is not a structure which can prevent cancer invasion and the discontinuity or intermittency of staining for LN and C IV in cancers is a result of changes in the capacity to produce the BM components due to canceration of the cells.

Inhibitory effect of CV4151, a thromboxane A2 synthetase inhibitor, on ventricular arrhythmias induced by coronary artery occlusion in rats

The purpose of this study was to determine whether thromboxane A2 (TXA2) is involved in the development of ventricular arrhythmias produced by coronary artery occlusion. Ventricular arrhythmias were induced by coronary artery occlusion in 66 male Sprague-Dawley rats. Rats were separated into 4 groups, and saline (n = 19) or CV4151 (a TXA2 synthetase inhibitor)(10 mg/kg, n = 14; 30 mg/kg, n = 15; or 100 mg/kg, n = 18) was injected intravenously 5 min before coronary artery occlusion. The antiarrhythmic effect of CV4151 was assessed in terms of the number of ventricular premature complexes (VPCs), the combined duration of ventricular tachycardia (VT) and ventricular fibrillation (Vf), the incidence of Vf, and the mortality rate within 30 min after occlusion. The total number of VPCs was as follows; control: 1789 +/- 330 beats: 10 mg/kg group: 1289 +/- 302 beats: 30 mg/kg group: 1008 +/- 229 beats: 100 mg/kg group: 986 +/- 275 beats, with no significant differences between groups. The incidence of Vf was significantly reduced in the 30 mg/kg and 100 mg/kg groups, as was the combined duration of VT and Vf and the mortality rate. Our results indicate that the TXA2 synthetase inhibitor CV4151 reduces the incidence of lethal arrhythmias induced by coronary artery occlusion in rats.

[A 4-week intravenous toxicity study of the active metabolite (NM394) of prulifloxacin (NM441) in rats followed by a 4-week recovery test]

A repeated dose toxicity study of ( +/- )-6- fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H- [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid (NM394), the active metabolite of a new antibacterial agent, prulifloxacin, was conducted in Sprague-Dawley rats. Male and female rats were given the test material intravenously for 4 weeks at doses of 0 (control), 3, 10 and 30 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. There were no treatment-related effects on survival, clinical signs, body weight and food consumption. Ophthalmoscopic and hematologic examinations failed to show any abnormalities related to the treatment. Increased water consumption was observed in the 10 and 30 mg/kg groups. In these dose groups, increased urine volume and lowered urine specific gravity, and crystalline substance and small epithelial cells in urinary sediments were seen. Cloudy urine was also seen in the 30 mg/kg group. Blood chemical examination showed decreased gamma-globulin in the 10 and 30 mg/kg groups and increased BUN and creatinine in the 30 mg/kg group. Pathological changes caused by the treatment were as follows. In kidney, tubular nephrosis with crystalline substance was observed in the 10 and 30 mg/kg groups and its organ weight was increased in the 30 mg/kg group. Cecal weight was increased in the 30 mg/kg group. The above-mentioned changes were reversible except for decreased gamma-globulin. Plasma levels and urinary concentrations of the test material were increased in all dose groups with dose-related manner, whereby no sex differences were observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Toxicological findings were not observed in the 3 mg/kg group. The results show that the NOAEL of NM394 is 3 mg/kg for 4-week repeated dose toxicity in rats.

Tissue-specific regulation of angiotensinogen gene expression in spontaneously hypertensive rats

Angiotensinogen is expressed in many tissues besides the liver. Recent studies have suggested that abnormalities in the regulation of angiotensinogen gene expression may be involved in the development of hypertension. However, little information is available concerning the functional significance of tissue angiotensinogen. In this study, we measured plasma angiotensinogen concentration by radioimmunoassay and examined the expression of tissue angiotensinogen by Northern blot analysis in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Although plasma angiotensinogen concentration in SHR was comparable to that in WKY at 6 weeks of age, it was increased significantly at 14 weeks of age in SHR and became higher than that in WKY. The levels of hepatic angiotensinogen mRNA were similar in SHR and WKY, and the levels of aortic, adrenal, and renal angiotensinogen mRNAs were lower in SHR than in WKY at both 6 and 14 weeks of age. Brain angiotensinogen expression in SHR was higher than in WKY at 6 weeks of age and was comparable to that in WKY at 14 weeks of age. On the other hand, cardiac and fat angiotensinogen mRNA levels were significantly increased at 14 weeks of age in SHR. These results demonstrate that the expression of tissue angiotensinogen is regulated differently in SHR and WKY and indicate that the development of hypertension is accompanied at least temporally with increases in plasma angiotensinogen concentration as well as cardiac and adipogenic angiotensinogen mRNA in SHR.

Growth hormone deficiency in Dubowitz syndrome

Severe short stature as a result of intra-uterine growth retardation is one of the characteristics of Dubowitz syndrome. There have been few reports elaborating growth hormone secretory status in this syndrome. A child with Dubowitz syndrome, who was found to have complete growth hormone (GH) deficiency and who responded to growth hormone therapy, is described. This appears to be the first documentation of GH deficiency in this syndrome.

An intensive chemotherapy of adult T-cell leukemia/lymphoma: CHOP followed by etoposide, vindesine, ranimustine, and mitoxantrone with granulocyte colony-stimulating factor support

SUMMARY

An intensive combination chemotherapy regimen supported by granulocyte colony-stimulating factor (G-CSF) was evaluated in adult T-cell leukemia/lymphoma (ATLL) patients in a multiinstitutional, cooperative study. Vincristine 1 mg/m2 i.v. day 1, Adriamycin 40 mg/m2 i.v. day 1, cyclophosphamide 400 mg/m2 i.v. day 1, prednisolone 40 mg/m2 i.v. days 1 to 3 and 8 to 10, etoposide 35 mg/m2 i.v. days 1 to 8, vindesine 2 mg/m2 i.v. day 8, ranimustine 50 mg/m2 i.v. day 8, mitoxantrone 7 mg/m2 i.v. day 8, and G-CSF 50 mg/m2 s.c. days 9 to 21 were given for 2 to 4 courses every 3 weeks to 83 patients with ATLL. Complete remission (CR) and partial remission (PR) were achieved in 35.8 and 38.3 percent, respectively, of 81 evaluable patients. The median survival of all patients was 8.5 months, with a predicted 3-year survival of 13.5 percent by the Kaplan-Meier method. The median duration of response was 7.6 months (range 0.2-42.7), and 13 patients were alive. Their median survival time was 29.1 months (range 19.2-44.7). In 67.6 percent of courses, white blood cell (WBC) nadirs were < 1.0 x 10(9)/L. Days required for the recovery of WBC from the nadir to > 1.0 x 10(9)/L were <5 days in 71.4 percent of the treatment courses. The G-CSF supported an intensified chemotherapy regimen for ATLL and yielded better response rate and longer survival compared to previous reports in Japan. Because duration of remission is still short, further studies of postremission therapy or other strategies are warranted.

[A 4-week oral toxicity study of prulifloxacin (NM441) in rats followed by a 4-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in Sprague-Dawley rats. Male and female rats were given the test material orally for 4 weeks at doses of 0 (control), 30, 300 and 3000 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. There was one case of death in the 3000 mg/kg group. Grayish green and soft feces, unkempt fur, transient deep respiration and decreased body weight gain were observed in the 3000 mg/kg group. Decreased food consumption and increased water intake were seen in the 300 and 3000 mg/kg groups. Ophthalmoscopic examination failed to show any abnormalities related to the treatment. In urinalysis, crystalline substance in the urinary sediments, cloudy urine and decreased Na+ excretion were observed in the 300 and 3000 mg/kg groups. Increased urine volume, lowered urine specific gravity and decreased K+ and Cl- excretions were seen in the 3000 mg/kg group. Hematologic examination showed decreased Hb, Ht, MCV and MCH and increased WBC in the 3000 mg/kg group. Blood chemical examination revealed increased BUN and decreased K+ and Cl- in the 3000 mg/kg group, and decreased K+ and gamma-globulin in the 300 mg/kg group. Pathological changes caused by the treatment were as follows. Cecal weight was increased in all dose groups. Cecal distention and swelling of its absorptive cells were seen in the 300 and 3000 mg/kg groups. In kidney, tubular nephrosis with crystalline substance was observed in the 300 and 3000 mg/kg groups, and its organ weight was increased in the 3000 mg/kg group. The above-mentioned changes were reversible except for decreased gamma-globulin, increased BUN and urine volume, and lowered urine specific gravity. Ulcer and small cavities associated with proliferation of fibrous tissue in the femoral articular cartilage were observed in the 3000 mg/kg group at the end of recovery period of 4 weeks. Plasma levels and urinary concentrations of active metabolite of the test material were increased in all dose groups with dose-related manner, whereby no sex difference was observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Increased cecal weight in the 30 mg/kg group was considered to be attributable to the pharmacological effect of the test material. The results show that the NOAEL of prulifloxacin is 30 mg/kg for 4-week repeated dose toxicity in rats.

[A 4-week oral toxicity study of prulifloxacin (NM441) in dogs followed by a 4-week recovery test]

A repeated dose toxicity study of prulifloxacin, a new antibacterial agent, was conducted in beagle dogs. Male and female dogs were given the test material orally for 4 weeks at doses of 0 (control), 30, 150 and 750 mg/kg. After discontinuation of the treatment, a 4-week recovery test was also conducted. Feces containing white material were seen in the 150 and 750 mg/kg groups. Salivation, prone, lateral or sitting position, gait disturbance, and locomotor depression were observed in the 750 mg/kg group. In this dose group, decreased body weight and food and water consumptions were also observed. There were no treatment-related effects on survival. Ophthalmoscopic and electrocardiographic examinations and urinalysis failed to show any abnormalities related to the treatment. Hematologic examination showed decreased WBC in the 750 mg/kg group. Blood chemical examination revealed increased GPT and alpha 2-globulin in the 750 mg/kg group. Pathological changes caused by the treatment were as follows. Rarefaction of matrix, cavitations and erosions in humeral and femoral articular cartilages, and inflammatory cell infiltration in synovium were seen in the 150 and 750 mg/kg groups. Focal hemorrhage in synovium was also observed in the 750 mg/kg group. In kidney, regeneration of tubular epithelium, inflammatory cell infiltration, fibrosis and crystalline substance in the tubular lumen were observed in the 750 mg/kg group. The above-mentioned changes were satisfactorily reversible except for the changes in the humeral and femoral articular cartilages and in the kidney. Plasma levels and urinary concentrations of active metabolite of the test material were increased in all dose groups with dose-related manner, whereby no sex difference was observed. No effects caused by the repeated dosing were seen in the plasma concentrations. Toxicological findings were not observed in the 30 mg/kg group. The results show that the NOAEL of prulifloxacin is 30 mg/kg for 4-week repeated dose toxicity in dogs.