Therapeutic effect of antimicrobial drugs against experimental infections due toYersinia pestis in mice

Although there are effective antibacterial agents against plague, newer antibacterial agents have been developed which show more potent activity against other bacterial organisms, but have not been tested againstYersinia pestis. A strain ofYersinia pestis was selected (no. 22; National Institute of Infectious Diseases, Tokyo, Japan) that caused a systemic infection in mice.Y. pestis no. 22 was intraperitoneally inoculated into DDY-strain mice, and 13 oral or 6 injectable antibacterial drugs given to the infected mice at varying doses 1 and 24 hours after infection. Levofloxacin, sparfloxacin and ofloxacin were the most effective oral agents against the infection, and prulifloxacin and pazufloxacin were also effective but to a lesser extent. Also, gentamicin and arbekacin were the most potent injectable antibacterial agents againstY. pestis. These results suggest that there are several new drugs, both oral and injectable, which exert excellent in vivo antibacterial activity against a mouse infection model and may be useful for the clinical treatment of plague.     

Effect of the free radical scavenger MCI-186 on spinal cord reperfusion after transient ischemia in the rabbit

Objective: Paraplegia remains a serious complication of aortic operations. The production of free radicals during reperfusion after transient ischemia is believed to induce secondary spinal neuronal injury, resulting in paraplegia. The aim of the present study was to clarify the protective effect and method of administration of antioxidants on the neurological and histological outcome in the animal model for reperfusion injury after transient spinal cord ischemia. Methods: New Zealand white rabbits underwent surgical exposure of the abdominal aorta that was clamped for 15 minutes to achieve spinal cord ischemia. Group A animals received two 10 mg/kg doses of 3-methyl-l-phenyl-2-pyrazolin-5-one (MCI-186) at the time of release of the aortic clamp and 30 minutes later. In group B, MCI-186, 5 mg/kg, was given three times, at the time of aorta clamp release, 30 minutes and 12 hours later. In group C (control group), one dose of vehicle was administered. Neurological status was assessed using modified Tarlov’s score until 168 hours after operation. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage. Results: Groups A and B animals had better neurological function than group C (p(0.001). In contrast, group C animals exhibited paraplegia or paraparesis with marked neuronal necrosis. The number of surviving neurons within examined sections of the spinal cord was significantly greater in group B than in group C (p(0.001). Conclusion: In a 15-minute ischemia-reperfusion model using rabbits, systemic repetitious administration of MCI-186, a free radical scavenger, was found to have a protective effect on the spinal cord neurons both neurologically and histologically. We postulate that the drug minimizes the delayed neuronal cell death for reperfusion injury after transient ischemia by reducing the free radical molecules. Moreover, it was thought that we could protect delayed neuronal cell death more effectively by administering MCI-18612 hours later.     

Cancer detection using a PET tracer, 11C-glycylsarcosine, targeted to H+/peptide transporter.

H+/peptide transporter, PEPT1, is functionally expressed in some human cancer cell lines and might be a candidate molecular target for detection of cancers in vivo using PET. The aim of the present study was to establish a novel tumor-imaging technology using a PET tracer targeted to H+/peptide transporter(s). We also compared the tracer with 18F-FDG, focusing on the specificity of their accumulation between tumor and inflammatory tissues. METHODS: A dipeptide PET tracer, 11C-glycylsarcosine (11C-Gly-Sar), was injected intravenously into athymic mice transplanted with human pancreatic, prostate, and gastric cancer cells. The distribution patterns of 11C-Gly-Sar and 18F-FDG in the tumor-bearing mice, and in mice with inflammatory tissue, were assessed by imaging with a positron planar imaging system (PPIS). Tissue distributions of tracer radioactivity were also measured. The expression levels of PEPT1 and PEPT2 (PEPTs) proteins in tumor xenografts and inflammatory tissue were examined by immunohistochemical analysis. The messenger RNA expression levels of PEPTs in 58 available cancer cell lines were quantified by means of real-time polymerase chain reaction. RESULTS: All 3 tumor xenografts were well visualized with the PPIS after injection of 11C-Gly-Sar. Expression of PEPTs in those xenografts was confirmed by immunohistochemical analysis. Tumor-to-blood concentration ratios of 11C-Gly-Sar increased in a time-dependent manner and were much higher than unity. Most of the radioactivity found in the tumor tissue was recovered as the intact tracer. These results indicated that 11C-Gly-Sar was taken up by the PEPTs in tumor xenografts. It is noteworthy that 11C-Gly-Sar was minimally present in inflammatory tissues that expressed no PEPT1 or PEPT2 protein, whereas 18F-FDG was highly accumulated, with the values of the selectivity index being >25.1 and 0.72 for 11C-Gly-Sar and 18F-FDG, respectively. The mRNAs of PEPT1 and PEPT2 were expressed in 27.6% and 93.1%, respectively, of the cancer cell lines examined in the present study. CONCLUSION: The present study indicates that 11C-Gly-Sar is a promising tumor-imaging agent and is superior to 18F-FDG for distinguishing between tumors and inflammatory tissue. Because PEPTs were ubiquitously expressed in various types of tumor cells examined, 11C-Gly-Sar could be useful for the detection of many types of cancers.     

Establishment of a monoclonal antibody directed to the minor novel gangliosides in bovine brain and cultured neural cell lines

We established a MAb N-25 reacted with a minor unknown antigen (AgX) in a commercially available GQ1b sample. It also recognized minor antigens in bovine brain (X-1, 2, 3, 4 and 5) and cultured neural cell lines (X-1). AgX is identical to X-5. X-5 is sialidase sensitive and has the common structure as X-1, which is resorcinol positive. These results suggested that novel gangliosides exist in bovine brain and neural cell lines.     

Absence of highly homologous sequence to HTLV-I in Japanese multiple sclerosis

We tried to detect HTLV-I-related sequences in Japanese patients with multiple sclerosis with a highly sensitive method that employs the polymerase chain reaction (PCR) of genomic DNA followed by Southern blot hybridization analysis. To amplify HTLV-I sequences, we used primers for LTR, pol, gag, and env coding regions. Fourteen patients with definite MS, 14 disease controls, 12 normal controls, and 3 patients with HTLV-I-associated myelopathy (HAM) were investigated. Results of particle aggregation assay for HTLV-I antibodies were negative in serum from all subjects except for the 3 HAM patients. Neither the 14 MS patients nor the 26 controls showed the presence of any highly homologous sequences to HTLV-I. We did observe faint signals for gag, pol, and env coding regions only at low stringent hybridization in some MS patients as well as some normal controls. The nucleotide sequence analysis of the faint bands was more homologous to major histocompatibility complex molecules than the HTLV-I genome.     

The prognostic significance of nuclear DNA content in non-small-cell lung carcinoma

The nuclear DNA content of paraffin-embedded specimens of primary non-small-cell lung carcinomas was analysed using flow cytometry in 210 patients (80 squamous cell carcinomas, 99 adenocarcinomas, 19 large cell carcinomas and 15 others). The relationship between nuclear DNA content and prognostic factors was studied using multivariate analysis with Cox's proportional hazard model. 1) The frequency of DNA aneuploidy was 77.3% among 210 patients, and it significantly (p less than 0.05) increased with advanced stage and the presence of lymph node metastasis. 2) The patients with DNA aneuploid tumors had a significantly (p less than 0.001) less favorable prognosis than those with DNA diploid tumors among 179 patients with non-small-cell lung carcinomas. Similar results were demonstrated in 79 patients with stage I carcinomas and in 85 patients who underwent absolute curative resection. 3) Multivariate analysis using Cox's proportional hazard model showed that DNA ploidy was an independent prognostic factor for survival. Especially in the patients with absolute curative resection, DNA ploidy was the most important prognostic factor. In conclusion, flow cytometric nuclear DNA content analysis provided useful biological information, and DNA ploidy was an important and major independent prognostic factor in non-small-cell lung carcinoma.     

Intraocular penetration kinetics of prednisolone after subconjunctival injection in rabbits

Prednisolone concentrations in cornea, aqueous humor, and vitreous humor and the residual amount in conjunctival tissue were assayed by high-performance liquid chromatography during a 14-hour period after subconjunctival injection of prednisolone sodium succinate in rabbits. Prednisolone was concentrated in the corneal epithelium and reached a peak within 5 min, whereas the peak level of prednisolone in stroma-endothelium was achieved 1 h after the injection. There was an apparent linear binding of prednisolone with the ocular tissue homogenates and fluids except for the vitreous humor. However, the protein binding of prednisolone with vitreous humor showed marked concentration dependency. A pharmacokinetic model involving a rapid conversion to prednisolone from its ester prodrug, first-order transfer to various tissues, and first-order elimination of unbound prednisolone from vitreous humor succeeded in predicting the observed concentration-time profiles of prednisolone in various ocular tissues and fluids after subconjunctival injection at three different doses: 0.1, 1.0, and 10.0 mg/kg. The present model predicted that absorption into precorneal area and epithelium and direct penetration into aqueous humor and vitreous humor are 1.7, 0.1, and 0.2% of the applied dose, respectively, and that almost the entire dose (98%) is absorbed into the systemic circulation, with a half-life of 38 min.     

Mu rhythm: clinical assessment of the atypical type]

Of 5,218 patients who received EEG examination at our laboratory during a 9-month period in 1989, 241 showed the 7-13 Hz arch-shaped activity originating from over the Rolandic area known as mu rhythm. These subjects were divided into two groups as follows: Group 1, 171 subjects showing typical mu rhythm, i.e., recorded during wakefulness and not affected by visual stimulation but blocked voluntary movements or tactile stimuli; and, Group 2, 70 subjects showing atypical mu rhythm, i.e., accentuated or activated by drowsiness, photic stimuli, or hyperventilation. No difference between the two groups was found with regard to frequency, amplitude or origin of the mu rhythm. Age distribution for Group 1 showed a peak between the ages of 6 and 15 (67.5%), while that for Group 2 peaked between the ages of 11 and 15 (35.7%) considering high incidence in older age range. There was no significant difference between the two groups in regard to gender. Although both groups showed a high incidence of epilepsy, Group 2 showed higher incidence of intractable epilepsy (p less than 0.05), as well as of severe intracranial trauma and of organic brain disease. On EEG recorded among epileptic patients, paroxysmal discharge was more frequent in Group 2 (p less than 0.01), although no other difference between the two groups was observed. Atypical mu rhythm may indicate more severe epilepsy, and careful observation of patients with atypical mu rhythm is recommended.