Biomedical subjects
Publications and source records attributed to T Akimoto.
A case of intracranial epidural abscess, 20 years after allograftic cranioplasty was presented. The abscess was caused by bacterial implantation after a minor stab wound of the scalp over the cranioplastic plate. It seemed quite rare that the intarcranial abscess occurred 20 years after an allograftic cranioplasty.
An 86-year-old woman had acute anterior myocardial infarction. A doppler echocardiogram taken on the second day of onset revealed ventricular septal perforation (VSP). Cardiac catheter examination was conducted under intraaortic balloon pumping. An emergency operation was performed on the third day after the onset because of the progression of cardiac failure and an increase of the left to right shunt ratio to 63%. A pericardiotomy revealed approximately 200 ml of blood in the pericardial cavity and a rupture in the left anterior ventricular free wall. The VSP was in the anterior septum and measured approximately 10 mm in diameter. Necrotic tissues surrounding the VSP were effectively resected using an ultrasonic aspiration instrument. The defect, measuring approximately 30 mm in diameter, was closed using a Teflon felt patch and a horse pericardial patch. The patient recovered with no complications and was discharged on the 31st postoperative day. She is presently in good conditions 2 years after the surgery. Our patient was the oldest among the reported cases of surgical repair of VSP in Japan, and our repair surgery was conducted the earliest after onset among the reported surgical cases for VSP in patients at 80 years of age or older.
We describe 13 adult patients with reactive arthritis induced by tonsillitis. Arthritis occurred 710 days after tonsillitis and involved the wrists, knees, feet and sternoclavicular joints. Some cases had pain in the Achilles tendon areas. Synovial fluid examined in 4 patients was sterile. All patients except 3 showed unequivocal elevation of serum ASO and/or ASK. Streptococcus was isolated from tonsillar swabs in 7 patients. One had maculopapular erythema and 2 had abdominal pain of unknown origin, but none had cardiac involvement, chorea and subcutaneous nodule. HLA examination revealed that 4 had B39 (p <0.005). Eight cases were treated with antibiotics. Five cases underwent tonsillectomy. All tonsils had cryptic abscess. No exacerbation was seen thereafter. These cases probably represent reactive arthritis induced by tonsillitis and should be distinguished from other rheumatic diseases.
Interleukin-6 (IL-6) inhibitors are good potential therapeutic agents in human patients, and anti-IL-6 antibodies are among the best candidates. Here, we have successfully humanized mouse monoclonal antibody SK2, which specifically binds to IL-6 and strongly inhibits IL-6 functions. Since this antibody possesses N-linked carbohydrates on Asn-30 of VH region, which seems to be very close to an antigen-binding site, influence of these carbohydrates on antigen-binding was investigated. A biosensor study showed that the mouse SK2 Fab and its deglycosylated fragments had almost equal Kd (Kon/Koff), 26.8 nM (1.05 x 10(6)/2.81 x 10(-2)) and 24.7 nM (1.28 x 10(6)/3.15 x 10(-2)), respectively. Furthermore, a mutant chimeric SK2 antibody, in which the N-glycosylation site was removed from the VH region, showed a Kd of 11 nM, almost similar to that of the original chimeric SK2 antibody, determined by Scatchard analysis with 125I-IL-6. These data indicate the carbohydrates of mouse SK2 VH region do not significantly influence antigen-binding activity. In the next step, two versions of each humanized SK2 VL and VH regions were carefully designed based on the amino acid sequences of human REI and DAW, respectively. Only one alteration, Tyr to Phe, was made at position 71 in the two light chains, according to the canonical residue for LI. A N-glycosylation site was introduced on the two heavy chains, by changing Ser to Asn at position 30. All four combinations of humanized light and heavy chains could bind to IL-6 as well as the chimeric SK2 antibody. The light chain first version, however, could not efficiently inhibit IL-6 binding to its receptor, indicating the importance of the LI loop conformation for the inhibitory activity of SK2 antibody. In contrast, both versions of the heavy chains were comparable, in yielding good humanized SK2 antibodies, suggesting that the glycosylation of the SK2 VH region has no influence in recreating a functional antigen-binding site in this humanization.
Characteristics of specific 125I-omega-conotoxin GVIA (125I-omega-CgTX) binding and 125I-omega-CgTX labeling using bifunctional crosslinkers were systematically investigated in crude membranes from chick whole brain. Aminoglycosides and dynorphine A (1-13) inhibited the specific binding of 125I-omega-CgTX, but not that of the L-type calcium ion channel antagonist [3H](+)PN200-110. It seems likely that the inhibitory effect of dynorphine A (1-13) does not involve kappa-opiate receptors, based on results with the opiate receptor antagonist naloxone and the kappa-opiate receptor agonist U50488H. Spider venom, Cd2+ and La3+ inhibited the specific binding of 125I-omega-CgTX, as well as that of [3H](+)PN200-110. Various L-type Ca2+ channel antagonists did not affect the specific binding of 125I-omega-CgTX. 125I-omega-CgTX specifically labeled 135 kDa and 215 kDa bands in crude membranes under reduced and non-reduced conditions, respectively. The crosslinker disuccinimidyl suberate (DSS) yielded better 125I-omega-CgTX labeling than the other two crosslinkers tested. We investigated the effect of various Ca2+ channel antagonists on 125I-omega-CgTX labeling with DSS in detail, and found that there is a strong correlation between the effects of Ca2+ channel antagonists on 125I-omega-CgTX labeling of the 135 kDa band and specific 125I-omega-CgTX binding. These results suggest that aminoglycosides and dynorphine A (1-13) are specific inhibitors of specific 125I-omega-CgTX binding, and that labeling of the 135 kDa band with 125I-omega-CgTX using DSS involves the specific binding sites of 125I-omega-CgTX, perhaps including one of the neuronal N-type Ca2+ channel subunits in the crude membranes.
Characteristic of [125I]omega-conotoxin (omega-CgTX) labeling using bifunctional cross linker (dithio bis[succinimidyl propionate]:DSP) was systematically investigated in crude membranes from chick whole brain. [125I]omega-CgTX specifically labeled 216 kDa as a main and 236 kDa as a minor bands in the crude membranes under non-reduced condition, but not labeled under reduced condition. We investigated the effect of various Ca channel antagonists on [125I]omega-CgTX labeling with DSP in detail, and found that there is a strong correlation between the effects of Ca channel antagonists on [125I]omega-CgTX labeling of the 216 kDa band and specific [125I]omega-CgTX binding. These results suggest that labeling of the 216 kDa band under non-reduced condition with [125I]omega-CgTX using DSP involves the specific binding sites of [125I]omega-CgTX, perhaps including one of the neuronal N-type Ca channel subunits in the crude membranes.
We investigated the antitumor effects of a synthetic lipid A derivative, DT-5461a, in combination with indomethacin in three experimental tumor models (peritoneal carcinomatosis, liver tumor, and lung tumor models) of transplanted colon 26 carcinoma in mice. This carcinoma produces the immunosuppressive prostaglandin E2 (PGE2). Intravenous administration of DT-5461a alone resulted in little or no prolongation of survival time [increase in life span (ILS): -2%-22%]. When indomethacin was given in drinking water a slight or moderate increase in survival time was seen (ILS: 4%-45%). In contrast, the combination of DT-5461a and indomethacin induced an additive increase in life span (ILS: 16% to more than 193%). The strongest antitumor effect of this combined therapy was seen in the peritoneal carcinomatosis model; in this model, plasma PGE2 concentrations were considerably higher than in normal mice, and concentrations were further but transiently increased by DT-5461a administration. Following oral indomethacin administration, these elevated PGE2 concentrations were reduced to the level in untreated normal mice. Furthermore, intratumoral tumor necrosis factor (TNF) activity in the group receiving the combined therapy was significantly higher than that in the DT-5461a-treated group. No TNF production was induced by the administration of indomethacin alone. These results suggest that the antitumor effect of DT-5461a can be enhanced by combination with indomethacin, and that the inhibition of PGE2 production may have a role in this antitumor effect.
Circulatory support during operation for type A aortic dissection is controversial among many medical centers. In the last 21 years, 100 patients with type A aortic dissection underwent 102 operations including 2 reoperations, and 29 patients showed Marfan's syndrome. During operation, no cerebral perfusion technique was used through February 1985 (period I), antegrade cerebral perfusion was applied since March 1985 (period II), and retrograde cerebral perfusion was introduced in November 1990 (period III). Surgical results were compared among these subgroups. Operative mortality was 12.1% in 33 chronic and 57.1% in 7 acute patients in period I, 11.1% in 27 chronic and 54.5% in 11 acute patients in period II, and 6.7% in 15 chronic and 0% in 9 acute patients in period III (period II versus III; p = 0.04). Retrograde cerebral perfusion decreased permanent brain complications. The 5-year actuarial survival was 59.7% in period I and 63.2% in period II (not significant), and the 3-year survival of period III was 91.7%. Actuarial survival of period III was significantly higher than those of periods I and II (p < 0.05). Surgical repair of aortic arch with cerebral perfusion techniques reduced the residual aneurysms. These results show that surgical results of type A aortic dissection in this series improved with the introduction of retrograde cerebral perfusion and extended surgical procedures.
Various support techniques for surgical treatment of type B aortic dissection have been used and recommended in many medical centers. In the last 21 years, 55 patients with type B aortic dissection underwent 65 operations including 10 reoperations, and 10 cases showed Marfan's syndrome. As circulatory support during operation, venoarterial bypass mainly was used until March 1987 (period I) and low-dose heparinized left heart bypass was applied since April 1987 (period II). Surgical results were compared among subgroups by the Kaplan-Meier actuarial method and Cox-Mantel statistical analysis. After the operation, early mortality was 27.3% in 33 patients in period I and 9.4% in 32 patients in period II (p = 0.06). The incidence of fatal hemorrhagic complications was decreased significantly by using the left heart bypass technique (p < 0.02). The 5-year actuarial survival of type B dissection was 60.6% in period I and 79.2% in period II (p = 0.07). These results suggest that surgical results of type B aortic dissection in this series might be improved with the introduction of left heart bypass and extended surgical procedures.
The synthetic low-toxicity lipid A analog DT-5461a induces endogenous TNF production in mice. The activity of TNF so induced is probably the main contributor to the antitumor effect of this compound. In the present study, we investigated the mechanism by which DT-5461a induces TNF production in murine macrophage RAW 264 cells. DT-5461a mimicked the ability of LPS to induce TNF production in a dose-dependent manner. DT-5461a at higher concentrations inhibited specific binding of [3H]LPS to the cells and reduced LPS-induced TNF production to the level induced by DT-5461a alone. In addition, DT-5461a, as well as LPS, induced tyrosine phosphorylation of MAP kinases, the early signal transduction pathway of this production. Herbimycin A, an inhibitor of tyrosine kinase, inhibited the LPS- and DT-5461a-induced tyrosine phosphorylation, expression of TNF mRNA, and subsequent TNF secretion. These results suggest that DT-5461a and LPS induce TNF production in murine macrophages through the common receptor sites and the similar early signaling pathway.
Mouse monoclonal antibody, ONS-M21, directed against human medulloblastoma cells, has been humanized by complementarity determining region (CDR) grafting. A humanized ONS-M21 VH region, comparable to the original mouse ONS-M21 VH region, was easily constructed based on framework regions (FRs) 1, 2 and 3 from human EU antibody and on FR4 from human ND antibody. Five alterations in the FRs were made at amino acids 27, 28, 29, 30 and 94 which are all part of the canonical structure for CDR1 (H1). The humanized ONS-M21 VL regions were constructed based on the FRs from human REI antibody. We first identified five amino acid residues in the FRs at positions 20, 21, 71, 73 and 87 as having a possible adverse influences on antigen binding. None of the versions with a variety of combinations at these five positions showed any bindings to antigen. In order to identify the mouse residues that must be retained in the human FRs, hybrid VL regions were constructed by joining the mouse ONS-M21 VL region and the first humanized version within CDR2. The hybrid VL regions revealed that residues in FR1 and/or FR2 were critical in creating a functional antigen binding site. Redesigning several versions with alterations in FR1 and FR2 revealed that the Pro-46 residue was the only critical residue for creating an antigen binding site. This approach should be helpful in identifying key residues in difficult cases of antibody humanization.
We previously reported that DT-5461 exhibits potent antitumor effects on various murine syngeneic tumors, probably via activation of host immune systems. Of the various systemic administration routes, intravenous (i.v.) administration gave the best antitumor effects. When the total dose was fixed, multiple and intermittent applications resulted in greater therapeutic efficacy than single and daily applications, respectively. The therapeutically effective applications of DT-5461 induced endogenous tumor necrosis factor (TNF) activity in serum and tumor tissue. The TNF activity peaked at 1-2 h after the administration. Although TNF activity in the serum declined to an undetectable level by 4 h, intratumoral TNF activity persisted even at 16 h. TNF-alpha messenger RNA (mRNA) was clearly expressed in the tumor tissues as early as 0.5 h after the DT-5461 administration. DT-5461 also caused increases in interferon activity in tumor-bearing mice. In vivo treatment with anti-interferon-alpha/beta serum or anti-interferon-gamma serum, as well as with anti-TNF-alpha serum, significantly reduced the antitumor effect of DT-5461. DT-5461-induced endogenous TNF production was also inhibited by treatment with either of these anti-interferon antisera alone. These results suggest that intermittent i.v. administration is optimal for cancer treatment with DT-5461, and that the optimal application of DT-5461 causes a long-lasting production of intratumoral TNF-alpha that may play a crucial role in the antitumor mechanisms of this compound. Furthermore, endogenous interferons induced by DT-5461 are involved in the antitumor mechanisms of this compound, probably by regulating the intratumoral TNF induction.
Deodorizing effect of ozone was investigated comparing two types of compact ozonizing apparatus made on an experimental basis. The concentrations of ammonia and trimethylamine were examined as an indicator for deodorizing effect of ozone in animal rooms of rats and guinea pigs at laboratory animal facilities of three different universities. Both of the ozonizing apparatus were able to remove ammonia and trimethylamine in animal rooms, with no significant difference in the performance of the two apparatus.
A 17-year-old boy observed as a case with Ebstein's anomaly. Echocardiogram and ventriculogram revealed enlargement of the tricuspid valve ring, dysplasia of anterior and posterior leaflet of tricuspid valve, but the anatomy of the septal leaflet was almost normal. According to these findings, the diagnosis of this patient was isolated congenital tricuspid regurgitation. Tricuspid annuloplasty of DeVaga's method and Reed's method were done. Post-operative residual regurgitation was mild. These procedures were resulting in a successful course. Isolated congenital tricuspid valve insufficiency was extremely rare. Only 7 cases of isolated congenital tricuspid insufficiency successfully operated in Japan were collected.
Retrospective analysis was performed to evaluate the prognostic factors for loco-regional control and the results of re-irradiation for 28 patients with recurrent, poorly-differentiated squamous cell carcinoma (PDSCC) of the nasopharynx. Twenty-four of them received re-irradiation. Local, local plus regional and regional recurrences were observed in 19, five and four patients, respectively. Except for three patients, all had Stage IV disease at the initial diagnosis. The only parameters influencing loco-regional recurrence were T and N stage categories. The median latent period from initial treatment to recurrence was 18.5 (range, 2-100) months. There was no difference in latent period by first recurrence site, although recurrent tumors confined to the nasopharynx or those only regionally developed had a longer latent period. Only four patients developed secondary distant bone metastases with a median latency of three months from loco-regional relapse. The patients with local recurrent tumors confined to the nasopharynx, and those with regional recurrences only, could be salvaged by re-irradiation, with five-year survival rates of 44 and 100%, respectively. Five of 28 patients (18%) developed severe chronic radiation sequelae: cerebrospinal complications in four patients, bilateral neck fibrosis in one. We conclude that recurrent PDSCC of the nasopharynx can be controlled by re-irradiation with some success. Radiation therapy techniques must, however, be carefully planned in order to avoid the severe late post re-irradiation sequelae. For patients with advanced non-curable local recurrences, palliative care should be recommended instead of agressive re-irradiation.
Distribution of Corynebacterium kutscheri was determined in 41 rats housed in a conventionally managed colony that were infected naturally and subclinically. At 2, 5, 10, 20 and 25 months after initial isolation of C. kutscheri, attempts were made to isolate C. kutscheri from 17 sites, with a new selective medium, FNC agar. In total, the prevalence (97.6%) of C. kutscheri isolation was significantly (P < 0.001) higher than the frequency (70.7%) of antibody detection. None of the rats manifested any distinct clinical signs of disease and macroscopic lesions caused by C. kutscheri were not detected. In 40 rats with subclinical infection, the organisms were most frequently isolated from the oral cavity, esophagus, cecal contents, and colon and rectum (> 95.0%). The isolation rate was next highest in the trachea, submaxillary lymph nodes, and nasal cavity (47.5 to 52.5%). The organisms hardly colonized the lung, liver, and kidney. Mean numbers of organisms found in the esophagus, cecal contents, and colon and rectum ranged from 10(3.9) to 10(4.2) CFU/g, and were significantly (P < 0.05, P < 0.01) high in comparison with those in the lung. These results indicated that many healthy rats in the naturally infected colony harbored C. kutscheri, and the organisms colonized the oral cavity, esophagus, cecal contents, and colon and rectum most frequently.
We previously showed that DT-5461a, a lipid A analog, has antitumor activity and relatively low toxicity in animals. To clarify its immunostimulatory effect we have studied the cytokine inducibility of DT-5461a and the mechanism involved in the cytokine expression in macrophages. While the activity is lower than that of LPS, DT-5461a enhanced production of TNF-alpha and GM-CSF in the murine macrophage cell line J774.1 in a dose-dependent fashion. Simultaneous addition of IL-4 inhibited DT-5461a and LPS-induced TNF-alpha production in a similar manner. Expression of cytokine mRNAs including TNF-alpha, IL-1 beta, IL-6, and GM-CSF was also enhanced by the treatment with DT-5461a. Treatment with cycloheximide indicated that the expression of TNF-alpha mRNA does not require new protein synthesis. Actinomycin D chase experiments revealed that cytokine mRNAs have rather long half-lives and we could not find significant changes in mRNA stability of cytokines in the J774.1 cells. The binding activity of a nuclear transcription factor NF-kappa B was enhanced by treatment with DT-5461a, suggesting enhanced transcription of cytokine genes. Specific binding of [3H]LPS to the cells was significantly inhibited by the addition of DT-5461a. These results indicate that DT-5461a enhances production of a variety of cytokines in macrophages through the LPS receptor sites and that this cytokine induction may occur primarily via transcriptional enhancement. These immunostimulatory effects may provide evidence for the mechanisms of the antitumor effect of this lipid A analog.
We previously showed that the synthetic lipid A derivative DT-5461a exhibited significant antitumor effects against various murine solid tumors, probably via activation of host immune systems. To clarify the participation of the macrophage-stimulating effect of DT-5461a in the antitumor mechanisms, we studied the ability of this compound to induce cytostatic macrophages and TNF production in murine systems. Cytostatic macrophages were induced by treatment with DT-5461a either in vitro or in vivo. DT-5461a also induced TNF production by resident peritoneal macrophages or spleen cells obtained from untreated mice. When spleen cells prepared from DT-5461a-treated mice were re-stimulated in vitro with DT-5461a, no TNF was produced by cells obtained at 1 day after the treatment. This may be due to transient refractoriness of macrophages to the compound, since the response to re-stimulation with DT-5461a recovered in cells obtained at 3 or 5 days after treatment. Moreover, while the serum TNF production and antitumor effects by DT-5461a decreased on daily administration, they were elicited by intermittent administration at intervals of 3 days or more. This suggests that the antitumor effects of DT-5461a depend on the TNF-producing activity of macrophages. These results indicate that DT-5461a possesses significant macrophage-stimulating activity, and that macrophages so activated mediate the DT-5461a-induced augmentation of host response against solid tumors.