Allogeneic cell stimulation enhances cytomegalovirus replication in the early period of primary infection in an experimental rat model.

BACKGROUND: Cytomegalovirus (CMV) diseases commonly occur in allograft recipients in the early post-transplant period. However, factors responsible for the high incidence of CMV diseases during this period are not yet fully defined. METHODS: Wistar-Furth (WF; RT-1(u)) rats were inoculated with 10(4) plaque-forming units (PFU) of rat CMV (RCMV) intraperitoneally, and then transplanted with allogeneic lungs from Dark Agouti (DA; RT-1avl) rats or stimulated with 10(7) mitomycin C-treated spleen cells from DA rats by daily sub-cutaneous injections for 2 weeks. No immunosuppressive agent was used. Naive WF rats and WF rats grafted with syngeneic lungs or cells were used as controls. The level of RCMV replication in rats was assessed by infectious virus titers in tissues. RESULTS: The virus titers in salivary glands of allogeneic and syngeneic lung graft recipients were significantly higher than in naive WF rats. The level of RCMV replication in rats stimulated with allogeneic spleen cells was significantly higher than in the syngeneic recipient rats: virus titers in the salivary gland of allogeneic and syngeneic recipients reached 4.61 +/- 0.33 and 4.00 +/- 0.37 log(10) PFU/g tissue, respectively, at 14 days post-infection (p = 0.015). The augmented viral replication in allogeneic recipients was confirmed by an increase in the number of RCMV antigen-positive macrophages present in tissue sections of the salivary gland. CONCLUSIONS: Acute lung allograft rejection and allogeneic spleen cell stimulation enhance CMV replication in the salivary gland of rats. Various responses to allogeneic antigens occurring in the process of acute allograft rejection could be risk factors for post-transplant CMV replication and infection.     

Characterization of polypeptides in Rickettsia tsutsugamushi: effect of preparative conditions on migration of polypeptides in polyacrylamide gel electrophoresis.

The polypeptide compositions and antigenic components of Rickettsia tsutsugamushi were analyzed by modifying the solubilization conditions prior to polyacrylamide gel electrophoresis and by using monoclonal antibodies in immunoblotting experiments. Several polypeptides were converted to larger or smaller molecules by using various conditions for rickettsial sample preparation. Solubilization of a sample in 2-mercaptoethanol-containing buffer resulted in conversion of high-molecular-weight polypeptides to smaller polypeptides and conversion of some of the 43-kilodalton (43K) polypeptide to a 46K polypeptide. The heat modifiability of selected polypeptides was shown by heating samples at 100 degrees C. A major polypeptide on the rickettsial surface which showed strain-specific antigenicity appeared at the 43K position in samples solubilized at 37 degrees C but moved to the 56K position after samples were heated at 100 degrees C. Immunoblotting with an anti-56K polypeptide monoclonal antibody demonstrated that the reactive antigens existed predominantly as the higher-molecular-weight polypeptides. These polypeptides were converted to 43K polypeptides at 37 degrees C or the 56K polypeptides at 100 degrees C by cleavage of disulfide linkages with 2-mercaptoethanol treatment.     

Effects of phenytoin on cell-mediated immunity

Phenytoin is a highly effective anticonvulsant agent that is widely administrated to prevent some kinds of patients with brain tumor. But it has been said that phenytoin may have some immunosuppresive potential for hosts. In this study, we evaluated the effects of phenytoin upon cellular immunity such as NK, CTL and LAK activity in murine models. Fresh splenocytes were taken out from mice (CBA/J, C 3 H/HeN, C 57 BL/6) into which phenytoin had been injected intraperitoneally at a daily dose of 1,000 micrograms for 28 days. The serum concentration of phenytoin in the experimental models was 10-20 micrograms/ml. The cytotoxic activities were estimated by a 4-hr 51Cr release assay. The mitogen-stimulated lymphocyte function was evaluated by 3H-thymidine incorporation into DNA. The NK activity was estimated by cytotoxicity of splenocytes of CBA/J mice against NK-sensitive YAC-1 cells. The cytotoxic T-lymphocyte (CTL) activity was estimated by cytotoxicity of splenocytes of C 57 BL/6 mice which were stimulated in vitro for 5 days by splenocytes of C 3H/HeN treated with mitomycin C, against RSV-M glioma cells. Lymphokine-activated killer (LAK) activity was estimated by cytotoxicity of LAK cells, which were induced from splenocytes of C 3 H/HeN mice by human recombinant interleukin-2 (rIL-2), against syngeneic RSV glioma and allogeneic 203 glioma cells. 3H-thymidine incorporation of splenocytes of C 57 BL/6 mice was reduced significantly (p less than 0.01) in phenytoin-treated mice. The cytotoxicity of splenocytes of non-treated CBA/J mice against YAC-1 cells was 75%, but that of phenytoin-treated CBL/J mice was a few %.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chemotherapy-induced anemia in patients with primary lung cancer.

To elucidate the factors which influence the value of hemoglobin, the nadir value of hemoglobin, frequency of blood transfusion and prognostic value of blood transfusion in patients with primary lung cancer during intensive chemotherapy, the hematological features of 124 patients entered into a randomized phase III study containing cisplatin were retrospectively analyzed. There was no difference in the percent nadir hemoglobin value of the first course of chemotherapy (% of pretreatment value) in any of the subgroups with respect to sex, body weight loss, performance status, age, stage, number of metastatic sites or treatment arms. The only predictive indicator for the nadir hemoglobin value in the first course of chemotherapy was the pretreatment value of hemoglobin. The equation for the regression line was y = 1.07 + 0.73x (R2 = 0.663, p < 0.001). The lowest nadir hemoglobin value (% of pretreatment value) during all chemotherapy courses was significantly lower in the subgroups older than 60 years and those with body weight loss. There was an inverse correlation between the accumulated dose of cisplatin and the lowest nadir hemoglobin value (p < 0.05). The frequency of blood transfusion in patients with more than two metastatic sites was significantly higher than in those with one or no metastatic sites (p < 0.05). Survival of patients who had required blood transfusion after chemotherapy was significantly shorter than that of patients who had not (p < 0.05).     

Phase I Study of Paclitaxel by Three-hour Infusion: Hypotension Just after Infusion Is One of the Major Dose-limiting Toxicities

The primary objectives of this study were to determine the maximum tolerated dose (MTD) of paclitaxel administered by 3-h infusion to patients with solid tumors, and to characterize the pharmacokinetics of a 3-h infusion in comparison with those of a 24-h infusion. Twenty-seven patients each received one of six levels of paclitaxel, 105, 135, 180, 210, 240 and 270 mg/m², with premedication. Two patients given 240 mg/m² and one patient given 270 mg/m² unexpectedly had grade 3/4 hypotension just after finishing the paclitaxel infusion. Peripheral neuropathy was also dose-limiting at 270 mg/m². Although granulocytopenia was significantly less severe than with a 24-h infusion, more than half of the patients experienced grade 4 toxicity at doses of 240 or 270 mg/m². Severe hypersensitivity reactions (HSRs) were not observed. Pharmacokinetic studies using high performance liquid chromatography demonstrated proportionally greater increases in the peak plasma concentration and area under the curve, and decreases in clearance and volume of distribution with increasing dose, suggesting non-linear pharmacokinetics of paclitaxel when given by 3-h infusion. The MTD of paclitaxel given as a 3-h infusion was determined to be 240 mg/m² with dose-limiting toxicities of granulocytopenia, peripheral neuropathy and hypotension. Hypotension just after infusion, induced by 3-h infusion of paclitaxel, is a new observation which has not been reported previously. The recommended dose for phase II study is 210 mg/m². Although hypotension was observed as an unexpected toxic effect, paclitaxel could be administered safely over 3 h with premedication and proper monitoring, resulting in reduced myelotoxicity and with no increase in the incidence of HSRs as compared with a 24-h infusion.     

Cyclic adenosine monophosphate promotes the proliferation of chicken granulosa cells in culture.

The aim of this study was to determine if cAMP regulates the proliferation of chicken granulosa cells and if there is a difference in the effects of cAMP on the granulosa cell proliferation between the largest follicle (F1) and the smaller follicles. Granulosa cells collected from F1 and the third largest follicle (F3) were cultured in medium M199 containing 1% calf serum with or without dibutyryl cAMP (dbcAMP). Proliferation of granulosa cells of F1 was promoted by dbcAMP in a dose-dependent manner. The most effective concentration of dbcAMP to promote the granulosa cell proliferation was 2 mM. In the culture without dbcAMP, the number of the granulosa cells was not changed significantly for 6 days, whereas, in the presence of 2 mM dbcAMP, the number of the granulosa cells was markedly increased during 2 to 6 days. The proliferation of the granulosa cells of F3 was stimulated by dbcAMP in the same manner as that of F1. Morphologically, the granulosa cells of F1 and F3 cultured for 2 days had a sheet-like appearance in control culture, whereas they were contracted, leaving finger-like cytoplasmic processes attached to the adjacent cells and substratum in the presence of 2 mM dbcAMP. After 6 days culture, approximately 90% of the cells of F1 stained positive for 3 beta-hydroxysteroid dehydrogenase activity in 2 mM dbcAMP-containing culture, whereas only about 20% of the cells were positive in control culture. These results suggest that cAMP promotes the proliferation of the granulosa cells during the follicular growth and this response of granulosa cells to cAMP is similar for F1 and F3.     

Reoperation after aortic valvuloplasty for aortic regurgitation associated with ventricular septal defect

Five patients underwent reoperations because residual or recurrent aortic regurgitation occurred after aortic valvuloplasty for aortic regurgitation associated with ventricular septal defect. The mean age at reoperation was 22 years old, and the mean time interval between initial and second operation was 6 years, 10 months. The pathological findings of the aortic valves showed tears and perforation of repaired leaflets in four patients and a giant pseudoaneurysm of the Valsalva sinus in one. Aortic valvuloplasties were performed again in three patients, and aortic valves were replaced with prosthetic valves in two. Slight to moderate regurgitant murmurs are still audible in patients who underwent these valvuloplasties. Ventricular septal defects should be closed before aortic regurgitation develops. If it has developed, however, valvuloplasty should be considered as a first choice in young patients. For adult patients, aortic valve replacement is recommended.     

Preferential inhibitions of hepatic P450IA2 expression and induction by lead nitrate in the rat

Male F344 rats were treated with lead nitrate and changes inthe expression and induction of P450IA subfamily enzymes anda placental form of glutathione-S-transferase (GST-P) in theliver were assessed by means of a bacterial mutation test, immunoblottingwith a monoclonal antibody reactive to P450IA1/IA2 and anti-GST-Psera and Northern blotting with P450IA2 cDNA as a probe. Treatmentof rats with lead nitrate (20, 50 or 100 µmol/kg bodywt) decreased P450IA2 mRNA and protein in the liver in the dose-dependentfashion and also decreased the microsomal activity for P450IA2-dependentmutagenization of aromatic amines. Pretreatment of rats withlead nitrate suppressed the inductions of both P450IA2 mRNAand protein by an inducer of P450IA subfamily enzymes in theliver. In addition, amount of the induced P450IA2 was decreasedalong with increase in that of the induced GST-P.     

A Synergistic Effect Between PG490-88 and Tacrolimus Prolongs Renal Allograft Survival in Monkeys

This study was undertaken to determine if PG490-88 and tacrolimus (Tac) act synergistically to prevent renal allograft rejection in monkeys and to explore possible mechanisms of synergy between these agents. MHC-mismatched renal allografts were transplanted into cynomolgus monkeys after bilateral nephrectomy. Recipients were divided into the following groups: (i) no treatment; (ii) PG490-88 (0.03 mg/kg); (iii) Tac (1 mg/kg); (iv) PG490-88 (0.01 mg/kg) + Tac (1 mg/kg) and (v) PG490-88 (0.03 mg/kg) + Tac (1 mg/kg). Through synergy PG490-88 and Tac inhibited anti-CD3/PMA-induced T-cell proliferation and IFN-gamma expression in vitro. Tac monotherapy only marginally prolonged survival (27 +/- 3.2 days), while the combination of PG490-88 and Tac significantly prolonged graft survival to a median of 99 days (PG490-88 at 0.03 mg) and 38.5 days (PG490-88 at 0.01 mg/kg). Prolonged survival correlated with inhibited IgM production as well as reduced T-cell infiltration, IL-2 protein expression and NF-AT/NF-kappaB activity. We conclude that PG490-88 and a subtherapeutic dose of Tac significantly prolong renal allograft survival in monkeys through the synergistic inhibition of T-cell activation and a decrease in IFN-gamma production and NF-AT/NF-kappaB activity.