A novel immunosuppressant, FTY720, with a unique mechanism of action, induces long-term graft acceptance in rat and dog allotransplantation.

A new compound with an immunosuppressive property was purified from culture filtrates of Isaria sinclairii and was chemically modified to FTY720. Rat spleen cells incubated with FTY720 demonstrated features characteristic of apoptosis--such as the absence of surface microvilli, chromatin condensation, and the formation of apoptotic bodies--by electron microscopy, and genemic DNA fragmentation by agarose gel electrophoresis. When FTY720 was administered in liver-allografted rats at a dose of 0.5 mg/kg from day 1 to day 14 after transplantation, the recipients survived significantly longer than the control group. Pretransplant treatment with 5 mg/kg of FTY720 one day before and on the day of grafting induced a remarkable prolongation of recipient survival, and three of 10 recipients survived for longer than 50 days. Furthermore, administration of FTY720 at 5 mg/kg on days 3 and day 4 after grafting also prolonged survival. In canine kidney allografting, a pretransplant 2-day course of FTY720 at 5 mg/kg prolonged graft survival. Daily administration of FTY720 in combination with CsA resulted in a significant prolongation of graft survival in a synergistic manner. In addition, FTY720 appeared to be nontoxic in canine recipients. These results demonstrated that FTY720, having a unique mechanism of action, induces long-term graft acceptance in rat and dog allotransplantation.

Chemokine responses and accumulation of inflammatory cells in the lungs of mice infected with highly virulent Cryptococcus neoformans: effects of interleukin-12.

We examined the mechanisms involved in the development of lung lesions after infection with Cryptococcus neoformans by comparing the histopathological findings and chemokine responses in the lungs of mice infected with C. neoformans and assessed the effect of interleukin (IL) 12 which protects mice from lethal infection. In mice infected intratracheally with a highly virulent strain of C. neoformans, the yeast cells multiplied quickly in the alveolar spaces but only a poor cellular inflammatory response was observed throughout the course of infection. Very little or no production of chemokines, including MCP-1, RANTES, MIP-1alpha, MIP-1beta and IP-10, was detected at the mRNA level using RT-PCR as well as at a protein level in MCP-1, RANTES and MIP-1alpha. In contrast, intraperitoneal administration of IL-12 induced the synthesis of these chemokines and a marked cellular inflammatory response involving histiocytes and lymphocytes in infected mice. Our findings were confirmed by flow cytometry of intraparenchymal leukocytes obtained from lung homogenates which showed IL-12-induced accumulation of inflammatory cells consisting mostly of macrophages and CD4+ alphabeta T cells. On the other hand, C-X-C chemokines including MIP-2 and KC, which attract neutrophils, were produced in infected and PBS-treated mice but treatment with IL-12 showed a marginal effect on their level, and neutrophil accumulation was similar in PBS- and IL-12-treated mice infected with C. neoforman. Our results demonstrate a close correlation between chemokine levels and development of lung lesions, and suggest that the induction of chemokine synthesis may be one of the mechanisms of IL-12-induced protection against cryptococcal infection.

Histopathology of cryptococcosis and other fungal infections in patients with acquired immunodeficiency syndrome.

OBJECTIVE: To gain insight into the histopathologic characteristics of fungal infection in acquired immunodeficiency syndrome (AIDS). METHODS: A review was conducted of the histopathology for 162 patients with evident fungal infection. RESULTS: The microscopic appearance of esophageal candidiasis that was common in patients with single organ involvement revealed necrotic debris containing proliferating hyphae at the site of mucosal erosions without fungal invasion of underlying tissue. The incidence of oral and esophageal candidiasis was followed by that of pulmonary aspergillosis and Candida infection. Eighteen patients had generalized cryptococcosis, representing the commonest generalized fungal disease. The essential histologic features of the disease consisted of yeast cell proliferation with a histiocytic response, but only minor lymphocytic and neutrophilic components. This was different from the manifestations of both Candida and Aspergillus infections. The two histologic patterns recognized in the pulmonary cryptococcal lesions could be graded with respect to the degree and type of inflammatory reaction. The milder one consisted of small scattered foci of intra-alveolar cryptococcal proliferation with a histiocytic response. Another pattern involved massive cryptococcal infection, which might be simply more extensive than that in the former. Capillary involvement of alveolar septa was an important common finding in all 18 patients.

Contribution of myeloperoxidase to coronary artery vasculitis associated with MPO-ANCA production.

The role of myeloperoxidase (MPO) in the pathogenesis of vasculitis associated with MPO-specific anti-neutrophil cytoplasmic autoantibody (MPO-ANCA) was examined in a murine animal model. Coronary artery vasculitis was induced in C57BL/6 mice with and without endogenous MPO by intraperitoneal injection of Candida albicans-derived substances (CADS). The corresponding levels of MPO-ANCA in sera of mice with and without vasculitis were measured and compared in both wild-type and MPO-deficient animals. The MPO-ANCA titers in sera were significantly higher in mice with vasculitis than in vasculitis-negative mice, indicating that MPO-ANCA correlated with vasculitis formation. However, the increase of MPO-ANCA titers observed in sera of wild C57BL/6 mice were strongly suppressed in MPO-deficient C57BL/6 mice, accompanied with prevention of vasculitis formation. These results show that MPO acted as an antigen for MPO-ANCA production by CADS and was followed by the vasculitis formation. Vasculitis did develop in a few MPO-deficient mice, though the incidence of vasculitis was much lower in MPO-deficient mice than in C57BL/6 mice.

Kawasaki disease. Relationship with infantile periarteritis nodosa.

Until 1972, Kawasaki disease, or acute febrile infantile mucocutaneous lymph node syndrome (MCLS), was considered in Japan to be a nonfatal disease with a favorable prognosis. Based on the findings from two autopsy cases of MCLS, we believe that sudden and unexpected death during convalescence may be due to arterial lesions, especially those involving the coronary artery, that resemble those of periarteritis nodosa. Of 29 autopsy cases of MCLS, gathered from all over Japan, all exhibited arteritis lesions (eg, aneurysm due to coronary arteritis). Such vascular pathological findings may in fact represent the same entity as infantile periarteritis nodosa. Whether infantile periarteritis nodosa can be identified with the adult type is still debatable. The particular manifestations of infantile periarteritis nodosa might be related to severe vasculitis. Autopsy cases of infantile periarteritis nodosa without MCLS manifestations are being collected and studied.

The intercostal artery in Kawasaki disease. A pathologic study of 17 autopsy cases.

Two hundred twenty-seven arteries from 17 autopsy patients having a history of Kawasaki disease were studied histopathologically and immunohistologically. Forty-five arteries in four cases (duration of illness ranging from 23 to 33 days) showed an arterial lesion characterized by reactive proliferative change of the medial smooth-muscle cells and frequent aneurysmal dilation. The lesion was mostly localized to the proximal portion. The intercostal arterial lesions were similar to those in the coronary arteries except for some delay in their occurrence. It is suggested that the proliferation of medial smooth-muscle cells after their degeneration is a key feature of the arterial lesion in Kawasaki disease.

[Deep-seated mycosis in patients with solid-organ transplantation--a study of autopsied cases in the United States].

Autopsies with solid-organ trans plantation (SOT) in UCLA Medical Center were reviewed, especially focussing on the deep-seated fungal infection and the incidence of fungal infections, causative fungi, and organs involved were evaluated. Deep-stated fungal infections were demonstrated in 21.0% of the patients with SOT. The incidence of fungal infections were 26.1% in kidney transplantation, which was the highest rate in SOT autopsies we reviewed, 25.0% in liver transplantation, 14.3% in lung transplantation, and 13.2% in heart transplantation. And the most common causative fungi were Aspergillus species, seen in 70.6% of SOT autopsies. In contrast, Candida species were observed in 25.5%. In addition, the incidence of deep-seated mycosis has been increasing since 1992, this was parallel to the increase of aspergillosis, most of which were found as a generalized spreading. In contrast, candidal lesions, were almost limited to the digestive tracts. The above suggests that from this standpoint, improvement of prophylactic and therapeutic technique against aspergillosis is the greatest problem in deep-seated mycosis in SOT patients.

[Cavernous hemangioma of the spermatic cord: a case report].

Cavernous hemangioma of the spermatic cord is a very rare disorder. A 26-year-old man was admitted to our hospital with chief complaints of right intrascrotal mass and hematospermia on October 19, 1990. Physical examination revealed a hard, non-transilluminated mass in the right spermatic cord. The mass was resected via the groin. Pathological examination showed cavernous hemangioma. The patient's postoperative course was uneventful. This is only the fourth case of cavernous hemangioma of the spermatic cord to be reported in the literature in Japan.

[Prostatic carcinoma presenting as an abdominal mass: a case report].

Prostatic carcinoma presenting as an abdominal mass is a very rare disorder. A 64-year-old man was referred to our hospital with the chief complaint of a right lower abdominal mass on March 6, 1984. Physical examination revealed a firm, smooth, fixed, non-tender, pulseless fist size mass in the right lower abdomen. Rectal examination revealed an apple size, smooth and elastic firm prostate which had an induration. Needle biopsy of the prostate showed well-differentiated adenocarcinoma. At first we regarded the abdominal mass as retroperitoneal tumor unassociated with prostatic carcinoma. After preoperative irradiation (20 Gy) to the pelvis, the abdominal mass was resected and bilateral orchiectomy was performed on April 11, 1984. The mass was histologically diagnosed as a metastatic lesion from prostatic carcinoma. On the basis of these findings, we considered the mass to be due to pelvic lymph node metastasis from prostatic carcinoma. His postoperative course was uneventful. In April 1991, he is still alive without evidence of recurrence or bone metastasis.

[An experimental study on the alteration of myocardial tissue by radiofrequency catheter ablation: differences according to the frequency and the device].

To evaluate the alteration of myocardial tissue by radiofrequency (RF) catheter ablation according to differences of the frequency and the device, we applied RF catheter ablation to canine right ventricular myocardium in vitro. The devices delivering RF energy were LL-49(0. 49MHz, fixed voltage mode), RA-50 (13.56MHz, fixed watt mode) and HAT200 (0.52MHz, fixed watt mode with the capability of temperature adjustment). After RF catheter ablation were performed with a unipolar electrode catheter at various output under the same condition of contact, the ablated lesions by each device were compared. Histologically, we recognized coagulation layer with the necrosis of endocardium and the dissociation of myocardium in each experiment. The degree and the size of ablation layer was significantly larger in lower frequency delivery (p less than 0.05) and was significantly smaller by using the device with temperature adjustment as compared with the others (p less than 0.05). It was suggested that the alteration of myocardial tissue ablated with RF energy differ according to the frequency and the mode of output adjustment of the device.

[The influence of repetitive delivery of radiofrequency current in catheter ablation].

The single delivery of radiofrequency current to the cardiac tissue can produce discrete small and shallow area of homogeneous coagulation necrosis. Little is known, however, concerning the influence of repetitive deliveries of radiofrequency current to the identical site of the ventricular myocardium. Therefore, in animal experiments using 8 dogs, we investigated the influences of those applications on the ventricular myocardium from the histological and electrocardiographical aspects. The used frequencies of radiofrequency current were 13.56 MHz (RF-50), 520 kHz (Hatt 200 S) and 500 kHz (LL-50). Released power was 25 Watts in current and 20 seconds in duration. The innings of application were 10, 20 and 30 times per one ablation session. The depth of ablated lesion became greater as the applied innings increased in any generator of radiofrequency current. The ablated lesion by the delivery over 20 times reached from the ventricular endocardium to the epicardium. In contrast, surface area produced by repetitive application was determined by the size and length of the tip of electrode catheter. T wave inversion and isolated premature ventricular contraction on electrocardiogram were observed only during repetitive radiofrequency energy application. Thus, since the repetitive delivery of radiofrequency energy to the identical myocardium caused the deep ablated lesion reached to the epicardium, caution should be taken against myocardial perforation in a clinical setting. However, this application could be useful for the ablation of deeper lesion responsible for ventricular tachycardia.

[An experimental study on transcoronary chemical ablation: comparison of ventricular tachyarrhythmias induced by chemical ablation according to different chemical materials].

The purpose of this study was to compare heart rate, appearance rate and duration of ventricular tachycardia (VT) by transcoronary chemical ablation using 95% ethanol and 1% aethoxysclerol respectively. After the balloon which was guided to the left or right coronary artery with PTCA technique in anesthetized dogs was inflated, chemical ablation was performed using ethanol (n = 5) or aethoxysclerol (n = 5). These chemicals were administered at 0.05 ml/sec with total dose of 0.50-1.50 ml. A quadripolar electrode catheter was used to record the intracardiac electrogram. VT occurred in all dogs (100%) after the administration of both ethanol and aethoxysclerol. In one dog using ethanol, VT developed into ventricular fibrillation, resulting in death. In dogs using aethoxysclerol, the heart rate and duration of VT were significantly lower and shorter than in those using ethanol (p < 0.05). There were no significant differences determined histologically in the ablated lesions caused by these different chemicals. We conclude that the severity of VT induced in all subjects by chemical ablation is different according to the materials applied, and that aethoxysclerol seems to be safer in comparison with ethanol.

[An experimental study of determining the appropriate frequency of radiofrequency catheter ablation in vitro and in vivo for ventricular tachycardias].

The purpose of this study was to examine the appropriate frequency of radiofrequency catheter ablation (RFA) for ventricular tachycardia. Radiofrequency energy generated by a device in which the frequency could be changed, was delivered from an electrode catheter with an electrode tip-width of 4 mm. RFA was performed for 10 seconds with 20W (50V x 0.4A) using 7 different frequencies from 10 to 500 kHz on ventricular myocardium in vitro and in anesthetized dogs. The ablated lesion was significantly larger with RFA of 200-300 kHz in both surface area and depth (p less than 0.05). The appearance of ventricular arrhythmia during RFA increased as the frequency decreased, and one dog applied with RFA of 100 kHz had spontaneous ventricular fibrillation resulting in death. All dogs with frequency less than 100 kHz had a muscle cramp during RFA. We conclude that appropriate frequency seems to be 200-300 kHz to obtain a large ablated lesion, and a frequency higher than 300 kHz seems suitable to avoid arrhythmia. We also conclude that a frequency under 100 kHz should not be used.