A case report of gastric carcinosarcoma with rhabdomyosarcomatous and neuroendocrinal differentiation

We report herein an unusual gastric carcinosarcoma with rhabdomyosarcomatous and neuroendocrinal differentiation in a 63-year-old Japanese male. The tumor was a pedunculated large polypoid tumor (7 x 6.5 x 3.5 cm) located in the pylorus. Histologically, it invaded to the subserosa and was composed of both adenocarcinomatous and sarcomatous components. Adenocarcinomatous foci generally showed tubular to solid patterns and occupied the parts facing the gastric lumen, while the sarcomatous components showed a generally irregular and solid arrangement. There were transitions between the sarcomatous and carcinoma elements. In addition, carcinoma cells with a cord-like or trabecular arrangement similar to that seen in endocrine carcinoma expressed chromogranin A, and were mainly observed in an intermediate area between the adenocarcinomatous and sarcomatous foci. The sarcomatous areas were mainly composed of spindle cells and occasionally contained a sarcomatous component showing rhabdomyosarcomatous differentiation. This is an interesting case to consider how the variety of cell type appeared in such a type of tumor in the stomach.

Functional reconstruction using a depressor anguli oris musculocutaneous flap for large lower lip defects, especially for elderly patients

Described here is a new technique to reconstruct large lower lip defects using one or two musculocutaneous island flaps, which includes an innervated depressor anguli oris muscle and has a facial artery in its pedicle. Vermilion is simultaneously reconstructed using a mucosal transposition flap. Three patients who had a total lower lip defect and five patients who had a defect larger than one-half of the lower lip were treated by our procedure. All the flaps survived completely without any signs of vascular stasis. In six patients, sphincter function and sensation appeared within 3 months after surgery. In one patient who needed a total lower lip reconstruction, the depressor anguli oris muscle was atrophic and the motor nerve could not be found. This patient could not regain motion. One other patient complained of a sialorrhea accompanied by sensory loss; however, his sensation improved within 6 months after surgery. All of the reconstructed lower lips were large enough to enable the patient to wear dentures and were of a cosmetically acceptable appearance 1 year after surgery.

Detection of brain metastasis in potentially operable non-small cell lung cancer: a comparison of CT and MRI

STUDY OBJECTIVE

To compare the usefulness of MRI and CT in the detection of brain metastases during preoperative evaluation and postoperative follow-up.

DESIGN

A prospective and sequential comparison.

PATIENTS AND METHODS

Of 332 patients with potentially operable non-small cell lung cancer who were free of neurologic signs and symptoms, brain CT was performed preoperatively on 155 patients (CT group) and brain MRI on 177 patients (MRI group). Patient characteristics in both groups were comparable. In 279 patients with complete resection of the primary lung tumor, intensive follow-up with CT and MRI was performed in the respective groups. The preoperative detection of brain metastases, postoperative intracranial recurrence rates, and characteristics of detected brain tumors were compared between the two groups. The survival of patients with brain metastases was also compared.

RESULTS

From the first evaluation to 12 months after surgery for primary lung cancer, brain metastases were observed in 11 patients (7.1%) from the CT group and 12 patients (6.8%) from the MRI group. MRI detected brain metastases preoperatively in 6 of the 12 patients (3.4% of the total MRI group), whereas CT detected brain metastases preoperatively in 1 of the 11 patients (0.6% of the total CT group). MRI showed a tendency toward a higher preoperative detection rate of brain metastases than CT (p = 0.069). Furthermore, the mean (+/- SD) maximal diameter of the brain metastases was significantly smaller in the MRI group (12.8+/-9.1 mm) than in the CT group (20.3+/-7.0 mm) (p = 0.041). However, the median survival time and 2-year survival rate after treatment of detected brain metastases, respectively, were 10 months and 27% in the CT group and 17 months and 28% in the MRI group. There was no significant difference between the groups in survival time.

CONCLUSIONS

Preoperative evaluation and intensive follow-up with MRI could facilitate early detection of brain metastases in patients with potentially operable lung cancer. However, further studies on detection and treatment of the metastatic tumors are considered necessary.

Endobronchial brachytherapy for recurrent thymoma showing endobronchial polypoid growth

The authors report a case of recurrent thymoma displaying endobronchial polypoid growth. Initially, the patient had invasive thymoma with intracaval growth into the right atrium. He was treated with multimodality therapy consisting of chemotherapy, surgical resection, and radiotherapy (50.4 Gy). Both 3 years and 6 years after the initial treatment, the tumor recurred outside the reconstructed superior vena cava. The patient was treated with repeated radiotherapy (50.4 Gy and 40 Gy), and remission was achieved. Eight years after the first therapy, an endobronchial polypoid lesion was detected in the right upper lobe bronchus and was histologically found to be thymoma. Endobronchial high-dose rate brachytherapy (20 Gy at 3 mm/5 fractions) was carried out for palliation because the recurrent tumor occurred outside of the superior vena cava area, which had been reirradiated. After the treatment, the endobronchial tumor shrunk remarkably in size without adverse effects. No tumor regrowth has been noted after a follow-up of 10 months.

A study of the concentration of orally administered sparfloxacin found in exudates from suture wounds beneath occlusive dressings

The concentration of orally administered sparfloxacin (SPFX), an antimicrobial agent, in exudates from the suture wounds beneath occlusive dressings has been measured. Twenty-one patients who received oral therapy with 100 mg of SPFX prior to surgery and 200 mg/day of SPFX after surgery were studied. During the operations, the suture wounds were covered by occlusive film. 48h post-operation, wound exudates under the dressings were drawn and measured using high performance liquid chromatography. SPFX values were 0.801+/-0.340 microg/ml (mean+/-SD). The results suggest that wound exudates beneath the occlusive dressing have concentrations of SPFX high enough to prevent infection in most cases when administered orally.

Reconstruction of congenital stenosis of external auditory canal with a postauricular chondrocutaneous flap

We describe here a new surgical technique for treatment of congenital stenosis of the external auditory canal using a postauricular chondrocutaneous flap. Our technique prevents recurring stenosis by cartilage support and provides a sufficient extension of the canal. The chondrocutaneous flap is safely elevated, easily reaches the canal, and has ample blood supply. It is beneficial for its self-cleaning function that the remnant canal, which contains cerumen glands, is used as part of the reconstructed canal. Six patients with congenital stenosis of the external auditory canal were treated by our procedure. In these patients, three patients were treated by a postauricular approach and the others were treated by an endaural approach. All patients had very satisfactory results.

Inhibition of neutrophil-mediated acute inflammation injury by an antibody against interleukin-8 (IL-8)

Chemokines are a family of cytokines regulating the migration and functions of leukocytes in a cell-type specific manner. A prototype of C-X-C chemokines, interleukin-8 (IL-8), chemoattracts and activates neutrophils in vitro, and IL-8 concentrations in body fluids are markedly increased in several neutrophil-mediated acute inflammation. Moreover, we previously reported that the administration of a neutralizing antibody to IL-8 prevented neutrophil-mediated tissue injury, as well as neutrophil infiltration, in several animal disease models. These observations implicate IL-8 as a major mediator of neutrophil-mediated tissue injury. Furthermore, we recently showed that an anti-IL-8 antibody effectively prevented two models that are very relevant to clinical situations; endotoxemia-induced acute respiratory distress syndrome (ARDS)-like lung injury and cerebral reperfusion injury. These results raise the possibility that IL-8 is a novel target for therapeutic intervention in neutrophil-mediated acute inflammation.

Effects of ligation of the internal iliac artery on blood flow to the bladder and detrusor function in rat

Ischaemia induced by atherosclerosis is a common cause of disorders in the elderly, including impairment of bladder function. To evaluate experimentally the effects of ischaemia on detrusor function, we performed infusion cystometry and evaluated the morphologic findings in the bladder of the rat. Blood flow to the bladder of the rat was evaluated with a Doppler flowmeter before and after the unilateral or bilateral ligation of the internal iliac arteries. Reevaluation was done at one and two weeks after surgery. Bladder function was studied by infusion cystometry performed in vivo under urethane anaesthesia. Finally, histological examination was performed. Blood flow at mid-dorsal wall of the control bladder was inversely related to intravesical volume. Unilateral or bilateral ligation of the internal iliac arteries decreased blood flow to the bladder, which showed a complete recovery two weeks postoperatively. Infusion cystometry of the ischaemic bladder with bilateral ligation of the internal iliac arteries demonstrated a decrease in voiding pressure, an increase in bladder capacity, and an increase in pressure at which micturition was initiated vs. the control. The bladder with unilateral ligation of the artery showed a decrease in voiding pressure, with no change in the other parameters. Histological examination indicated that the bilateral ischaemia and ischaemic side of unilateral ischaemia led to a degeneration of the mucosa, and severe oedema in submucosal and muscle layers one week postoperatively. Degeneration of smooth muscle was predominant at 2 weeks. Contralateral side of the unilaterally ischaemic bladder showed oedema and congestion of the submucosa and smooth muscle. Ligation of the internal iliac artery decreased blood flow to the bladder significantly, which resulted in smooth muscle degeneration. Consequently, in vivo voiding pressure was impaired in the ischaemic bladder.

Impairment of ocular surface epithelium barrier function in patients with atopic dermatitis

AIMS

To assess the integrity of the ocular surface epithelium in patients with atopic dermatitis from the viewpoint of its barrier function.

METHODS

49 patients with atopic dermatitis with blepharoconjunctivitis (ABC group), 27 age matched patients with seasonal or perennial allergic conjunctivitis (AC group), and 20 volunteers with normal healthy eyes (NH group) were assigned to this study. Ocular surface epithelium barrier function was evaluated by the fluorophotometric method using a slit lamp fluorophotometer. 3 microliters of 0.5% sodium fluorescein was instilled into the conjunctival sac of the right eye and fluorescein uptake (ng/ml) 30 minutes later (20 minutes after eye washing) was measured in the central cornea and the temporal bulbar conjunctiva. Fluorophoto metric measurements performed were analysed in each group and compared between the groups.

RESULTS

The ABC group showed significantly higher fluorescein uptake (mean 28.2 (SEM 3.3) ng/ml) in the cornea than the AC (11.4 (2.2), p = 0.001) and NH groups (9.3 (2.1), p = 0.001). There was no significant difference between the AC and NH groups (p = 0.930). The ABC group also showed significantly higher fluorescein uptake in the bulbar conjunctiva (393.4 (54.0)) than the AC (182.9 (24.6), p = 0.011) and NH groups (169.3 (29.1), p = 0.012). There was also no significant difference in fluorescein uptake between the AC group and the NH group (p = 0.987).

CONCLUSION

This study suggested that ocular surface epithelium barrier function is impaired in patients with atopic dermatitis with blepharoconjunctivitis.

Helical computed tomography diagnosis of pleural dissemination in lung cancer: comparison of thick-section and thin-section helical computed tomography

Pleural dissemination in lung cancer was prospectively evaluated by helical computed tomography (CT), and the usefulness of thick-section CT (10-mm collimation; pitch 1) and thin-section CT (2-mm collimation; pitch 1) were compared. The study included 54 patients with pulmonary adenocarcinoma in whom plain chest radiographs showed no evidence of pleural effusion and in whom the primary lesion was seen to be contiguous with the pleural surface on thick-section CT. Thin-section CT was performed for evaluation of the costal, mediastinal, interlobar, and diaphragmatic pleural surfaces. Pathologic examination revealed pleural dissemination in 20 patients (8 resected, 12 nonresected). Pleural dissemination was diagnosed in 12 patients on thick-section CT, and in 20 patients on thin-section CT. False negatives occurred in ten and two patients, respectively. The same two patients were false positives by both methods. Accuracy was 78% for thick-section CT and 93% for thin-section CT, and sensitivity was 50% and 90%, respectively. Thin-section CT provided more useful information than thick-section CT for the evaluation of pleural dissemination in lung cancer.

Long-term results of endarterectomy, anatomic bypass and extraanatomic bypass for aortoiliac occlusive disease

Over the past 20 years, 214 patients in our hospital were operated on for aortoiliac occlusion, including an endarterectomy for 88 legs in 64 patients, an anatomic bypass for 178 legs in 105 patients, and an extraanatomic bypass for 51 legs in 45 patients. The extraanatomic group was older than the other two groups (70 years versus 64 years), and also showed a higher instance of critical ischemic symptoms than the other groups (49% versus 16%). The 10-year primary patency rate was 88% for an endarterectomy, 91% for an anatomic bypass, and 73% for an extraanatomic bypass. The 10-year survival rate was 71% for an endarterectomy, 49% for an anatomic bypass, and 24% for an extraanatomic bypass. The possible complications related to each surgical method included sexual dysfunction resulting from endarterectomy, and graft infection and anastomotic aneurysm in the prosthetic bypass. No ischemic symptoms in the donor limb were noted following an extraanatomic bypass. The selection of the appropriate surgical method for aortoiliac occlusion should thus be made after a careful review of the patient's general condition, the morphology of arterial occlusion, and the risk of possible complications for each type of surgery.

Nonsurgical correction of congenital auricular deformities in children older than early neonates

It has been reported that nonsurgical correction of auricular deformities is not effective except in early neonates. We have succeeded in nonsurgical correction using thermoplastic splints for congenital auricular deformities on 50 ears of 45 patients without severe hypoplasia in children older than 1 year. Details of the types of ears we attempted to treat were 26 cryptotias, 5 lop ears, 5 Stahl's ears, 3 prominent ears, 3 shell ears, and 8 other miscellaneous conditions. The patients were between 1 and 14 years of age with an average age of 3.6 years. Our results were categorized as follows: excellent (the auricle was delicately corrected into a desirable form and satisfied the patient), improved (the auricle was corrected into a rough form that did not attain to a desirable shape and an irregular form still remained; however, its improvement satisfied the patient), recurrent (the auricle was initially corrected but the deformity recurred), not improved (the auricle was not corrected to the desired form and the result did not satisfy the patient), and gave up (the patient gave up before treatment could be completed). In our results, the average period of splint application was 2.1 months. In 27 of the 50 cases, the treated ears were excellent. Eleven ear cases showed improvement. Six cases showed recurrence. Three cases did not improve. Three patients gave up treatment. It is suggested that nonsurgical auricular correction is possible in almost all children, even if they are not early neonates, when corrections are made continuously and gradually.

Acute mesenteric vascular occlusion: analysis of 39 patients

OBJECTIVE

To study the factors that influence mortality and long term outcome of patients with acute mesenteric vascular occlusion.

DESIGN

Retrospective study.

SETTING

University hospital, Kanazawa, Japan.

PATIENTS

Thirty-nine patients treated between 1978 and 1995 for acute mesenteric vascular occlusion.

INTERVENTIONS

34 patients underwent laparotomy. Bowel was resected in 29 patients, and primary anastomosis was done in 20. The occluded vessel was revascularised in 5 patients.

MAIN OUTCOME MEASURES

mortality, short bowel syndrome and long term survival.

RESULTS

25 patients had arterial occlusions, and 8 venous. In the remaining 6, the occluded vessel was not identified. 11 Patients developed renal failure, 11 respiratory failure, and 10 disseminated intravascular coagulation (DIC). Twelve patients died within 30 days. The factors associated with early death were acidosis and high serum amylase activity. 9 Patients developed the short bowel syndrome. Survival was 49% at 1 year, and 34% at 5 years.

CONCLUSION

Mortality was higher in patients with advanced peritonitis. Mesenteric revascularisation should be attempted to avoid the short bowel syndrome.

[Antiphospholipid antibodies in the elderly patients with ischemic stroke]

The importance of antiphospholipid antibodies as a cause of ischemic stroke in young adults is well demonstrated in the previous studies, but the relationship between the elderly patients with ischemic stroke and antiphospholipid antibodies is not defined. The frequency of positivity for antiphospholipid antibodies was 5.4% (6 out of 112 elderly patients with ischemic stroke), and much higher than that of the elderly healthy individuals (none of 108 individuals) (p < 0.001). Equal numbers of stroke patients with or without antiphospholipid antibodies had other stroke risk factors. The clinical features of the elderly patients with ischemic stroke, who were positive for antiphospholipid antibodies, presented recurrent and multiple infarct dementia, and had thromboses of the other organs. The hemostatic state of the patients with positive antiphospholipid antibodies revealed, in particular, increased intravascular coagulation. Antithrombotic treatment with warfarin at high international normalized ratios (INRs: 1.47-2.80) were effective comparing with antiplatelet treatment with ticlopidine alone in preventing further thromboembolic events.

[Intralobar pulmonary sequestration with three aberrant arteries: a case report and review of the Japanese literature]

A case of intralobar pulmonary sequestration with three aberrant arteries was reported. The patient was a 26-year-old man. His chest film showed an abnormal shadow suspected of a pulmonary sequestration in the left lower lobe of the lung. Computed tomography of the chest revealed that the aberrant arteries originated from the descending aorta and circulated the emphysematous area of the left lung. Angiography clearly demonstrated three aberrant arteries and three veins draining into the hemiazygos and lower pulmonary veins. Pulmonary sequestration was diagnosed and then resected. Microscopically, the resected lung had emphysematous change, multiple cysts and winded vessels. Aberrant arteries were the elastic type of vessels and accompanied with atherosclerosis. According to the review of 139 Japanese cases of intralobar pulmonary sequestration, 7% of all patients had more than two aberrant arteries. Moreover, only 3% of patients had veins draining into the systemic vessels. In many cases the thin aberrant arteries were clearly demonstrated by angiography and the draining veins were detected. We consider that angiography is necessary to show definitely the aberrant arteries and drainage veins.

[Cystic thymoma without solid mass lesions on diagnostic imaging--a case report]

A 68-year-old man was referred to our hospital because of an abnormal shadow on a chest X-ray film. A chest CT scan and MRI demonstrated a cystic mass without solid lesions on the anterior mediastinum. The CT scan also showed that it was a well-defined and homogenous mass without contrast enhancement effect. 67Ga and 201T1 scintigrams showed no uptake in the mass. Needle aspiration cytology was performed, and there was no evidence of neoplasms. A thymic cyst was diagnosed, and then an operation was performed. At the operation, the cystic tumor was removed along with thymic tissues by a median sternotomy. On the cut section of the resected specimen, the tumor was found to be a cyst with small solid nodules on the wall. Pathologic examination revealed that the tumor was a cystic thymoma. We consider that patients with cystic tumors on the anterior mediastinum should obtain histopathologic diagnosis because of the difficulty in excluding neoplasms such as thymoma.

[Huge localized mesothelioma of the diaphragm in a 17-year-old female--a case report with calculated tumor volume doubling time]

An operative case of localized mesothelioma of the pleura developed in a 17-year-old female was reported. She was admitted to our hospital complaining of right chest pain. A chest X-ray film showed a huge mass in the right lower field of the lung. After the embolization of the right inferior phrenic artery, which was the main feeder to the tumor, it was then successfully resected combined with the right diaphragm and the right lower lobe of the lung. Histologically, the tumor was diagnosed as benign localized mesothelioma (solitary fibrous tumor of the pleura). Further histological and immunohistochemical study revealed that it had developed from the connective tissue under the parietal mesothelium of the diaphragm. As chest roentgenograms had been undertaken during past two years, the tumor volume doubling time was calculated at 153 days. Despite the short tumor volume doubling time as like primary lung cancer, she is alive without recurrence 5 years after the operation.

Effects of partial outflow obstruction on bladder contractility and blood flow to the detrusor: comparison between mild and severe obstruction

Detrusor dysfunction secondary to partial outflow obstruction is caused in part by decreased blood flow to the detrusor. We investigated changes in blood flow to the bladder and in bladder function after inducing partial outflow obstruction. The urethras of male Sprague-Dawley rats were constricted by sutures to degrees representing either mild and severe obstruction. Blood flow to the bladder was measured by a Doppler flowmeter prior to and 7 days after obstruction. In vivo and in vitro experiments were performed 7 days after surgery. After cystometry was used to determine bladder capacity, the pressure at which micturition was induced, and maximum voiding pressure, the bladder was removed and placed in an organ bath where increases in intravesical pressure in response to field stimulation were evaluated. Finally, volume-pressure studies were performed in order to determine passive detrusor compliance and response to field stimulation at each specific capacity in vitro. Although blood flow to the bladder was significantly decreased by severe obstruction, no differences in blood flow between control and mildly obstructed bladders was observed. While maximum voiding pressure decreased in severely obstructed bladders, both the pressure at which micturition was induced and bladder capacity were increased. The response to field stimulation was increased by mild obstruction but decreased by severe obstruction, although bladder compliance was increased by both. The peak response to filled stimulation was observed at a larger capacity in severely obstructed bladders than the others. In conclusion, when outflow obstruction was mild, blood flow to the bladder remained unchanged and detrusor contractility increased. On the other hand, severe obstruction decreased bladder blood flow and induced deterioration of detrusor function.

Pivotal role of interleukin-8 in the acute respiratory distress syndrome and cerebral reperfusion injury

Neutrophil recruitment is one of the hallmarks of acute inflammation. A potent neutrophil chemotactic and activating factor, interleukin-8 (IL-8), has been demonstrated to be elevated in body fluids in various human diseases and experimental animal models. Recent investigations on animal disease models using blocking antibodies to IL-8 have revealed the essential involvement of IL-8 in acute inflammation. We previously reported that the administration of a neutralizing antibody against IL-8 prevented the neutrophil infiltration and neutrophil-mediated tissue injury in several animal studies. In addition, we have recently demonstrated that anti-IL-8 treatment is also effective in prevention of two models that are very relevant to clinical situations: cerebral reperfusion injury and endotoxemia-induced acute respiratory distress syndrome-like lung injury. These results further support the hypothesis that IL-8 has a pivotal role and is a novel target for therapeutic intervention in neutrophil-mediated injury.

Effects of alpha-interferon on sperm production, concentration, and motility in the rat

BACKGROUND

We evaluated possible effects of alpha-interferon (alpha-IFN) on testicular spermatogenesis and epididymal sperm quality in the nude rat.

METHODS

Nude male rats were administered subcutaneous injections of human alpha-IFN daily for 3 months. The luminal content of the cauda epididymidis was collected by micropuncture. Daily sperm production was determined by Amann's method and sperm concentrations were determined by microassay. Progressive motility was judged by evaluating the linear distance traveled by the sperm in a diluent. Serum levels of testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were also measured at the end of the experiment.

RESULTS

Daily sperm production and epididymal sperm concentrations were significantly increased after administration of alpha-IFN, while progressive motility of the spermatozoa was not altered. Alpha-IFN significantly increased serum testosterone levels, while it decreased serum LH levels and left serum FSH levels unchanged.

CONCLUSION

Alpha-IFN may improve testicular spermatogenesis and increase the epididymal sperm concentration in the rat. These promising results with alpha-IFN may pave the way for a new approach to treating male infertility.

Comparison of cilostazol with warfarin as antithrombotic therapy after femoro-popliteal bypass surgery using an ePTFE graft

BACKGROUND

Cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4- dihydro-2(1H)-quinolinone) is a new antiplatelet agent with a vasodilating action. The purpose of this study was comparison of cilostazol with warfarin as antithrombotic therapy after femoro-popliteal bypass surgery using an expanded polytetrafluorethylene (ePTFE) graft.

EXPERIMENTAL DESIGN

This report is a retrospective study and the patients were followed up for five years.

SETTING

Outpatients of university hospital.

METHODS

Sixteen arteriosclerosis obliterans patients, who were diagnosed as having only superficial femoral artery stenosis or occlusion, underwent femoro-popliteal (above the knee) bypass using an ePTFE graft 6 mm in diameter. Cilostazol (150-200 mg/day) was administered to 6 cases (9 bypasses), and warfarin (prothrombin time was controlled to 15-25%.) was administered to 10 cases (14 bypasses).

RESULTS

No clinically characteristic differences were found between the two groups. The cumulative 1-, 3-, and 5-year primary and secondary graft patency rates were 69% and 80%, 69% and 80%, and, 69% and 80% in the cilostazol group, vs 61% and 91%, 51% and 91%, and, 51% and 91% in the warfarin group, respectively. These differences were not significant (p < 0.05). No hemorrhage complications were observed in the cilostazol group. The management of cilostazol administration was safe and simple.

CONCLUSIONS

Although the number of cases was small in this study, cilostazol was considered to be as effective as warfarin and suitable for the postoperative antithrombotic therapy after the ePTFE bypass surgery.

Attenuation of monosodium urate crystal-induced arthritis in rabbits by a neutralizing antibody against interleukin-8

Accumulating evidence implicates interleukin-8 (IL-8) as an essential mediator in neutrophil-mediated acute inflammation. Neutrophils have also been shown to have a crucial role in the pathogenesis of acute gouty arthritis. Thus, we investigate the pathophysiological role of IL-8 in an experimental model of acute gout, monosodium urate (MSU) crystal-induced arthritis in rabbits. The injection of MSU crystals into knee joints caused a marked swelling of joints. Concomitantly, the infiltration ofleukocytes, mostly neutrophils, was observed in synovial membrane and synovial fluids. The injection of MSU crystals also induced an elevation in synovial fluid IL-8 levels preceding neutrophil infiltration into synovial fluids, without an accompanying increase in plasma IL-8 levels. Immunoreactive IL-8 protein was detected in synovial lining cells at 12-24 h after the injection. IL-8 protein was also observed in infiltrated leukocytes in synovium as early as 3-24 h after the injection. Finally, the intraarticular injection of a neutralizing anti-IL-8 antibody significantly attenuated the crystal-induced joint swelling that occurred at 12 h, and neutrophil infiltration into arthritic joints at 12 and 24 h after the induction. These results provide evidence on the pathogenic roles of locally produced IL-8 in MSU crystal-induced gouty arthritis.