Effects of beta-lactamases and omp mutation on susceptibility to beta-lactam antibiotics in Escherichia coli.

Four types of beta-lactamases consisting of a penicillinase type I (TEM-1), a penicillinase type II (OXA-1), a cephalosporinase of Citrobacter freundii, and a cephalosporinase of Proteus vulgaris were introduced into Escherichia coli MC4100 and its omp mutants, MH1160 (MC4100 ompR1) and MH760 (MC4100 ompR2), by transformation. Effects of the combination of the omp mutations and these beta-lactamases on the susceptibility of E. coli strains were studied with 15 beta-lactam antibiotics including cephalosporins, cephamycins, penicillins, imipenem, and aztreonam. The ompR1 mutant, MH1160, lacks OmpF and OmpC, and it showed reduced susceptibility to 11 of the 15 beta-lactam agents. The reduction in susceptibility to cefoxitin, moxalactam, and flomoxef was much greater than reduction in susceptibility to the other agents. When the ompR1 mutant produced the cephalosporinase of C. freundii, the susceptibility of the mutant to 12 of the 15 beta-lactam antibiotics decreased. The reduction in susceptibility of MH1160 to 10 of the 12 agents affected by the enzyme was two- to fourfold greater than that observed in MC4100. Such a synergistic effect was also observed with the cephalosporinase of P. vulgaris and ompR1 mutation against six cephalosporins, moxalactam, and aztreonam.     

Enzyme-induced Aggregation and Disaggregation of Tumor Cells via the Cell Surface Glycocalyx in Association with Deoxyribonucleic Acid

Serine proteases cause aggregation of the rat ascites tumor cell lines AH 130, AH 109A and YS in vitro , and the tumor cell aggregates are dissolved by treatment with DNase I. We previously demonstrated that these events played a critical role in the augmentation or reduction of experimental blood borne metastasis of these cell lines. In the present study, the ultrastructural features of this protease dependent aggregation were analysed. Transmission and scanning electron microscopy revealed that after the protease treatment each tumor cell was surrounded by a thin membranous (sleeve-like) structure. This sleeve like structure was stained with ruthenium red to an intensity similar to the cell surface of the control. Adjacent cells became attached to each other with microvilli via this fine structure. Immuno-electron microscopy revealed DNA antigen as dense patches on the sleeve-like structure or as faint and diffuse deposits on the outer surface of the cells by indirect immunoperoxidase staining using an anti-DNA monoclonal antibody. Both the sleeve like structure and immunopositive deposits disappeared after treatment with DNase I. Neither cell viability nor the normal ultra-structure of their organelles was influenced by the enzyme treatment. These results indicate that serine protease induced tumor cell aggregation is due to cellular contact via the sleeve-like structure, which probably originates from the cell surface glycocalyx in association with DNA molecules of unknown origin.     

Review of the pandemic (H1N1) 2009 among pregnant Japanese women

Pregnant women are prone to serious complications when they contract influenza, and a considerable number of pregnant women died from the pandemic (H1N1) 2009 worldwide; however, no maternal mortality occurred in Japan during this pandemic. This review explores the reasons why maternal mortality did not occur in Japan. Two studies conducted during and soon after the pandemic (H1N1) 2009 in Japan suggested the following: 40,000-50,000 pregnant Japanese women took antiviral medicines for prophylaxis after close contact with an infected person; 40% of them (16,000-20,000) contracted the novel influenza and accounted for a half of all 30,000-40,000 pregnant patients with the novel influenza; at least 181 of them required hospitalization; and at least 17 of them developed pneumonitis. Hospitalized women had a 2.5 times higher risk of preterm delivery (at <37 weeks) compared with the general population. The two studies suggested that the following may have contributed to the lack of maternal mortality in Japan: (i) more than 60% of candidates were vaccinated within 1.5 months after the availability of a vaccine against the novel virus; (ii) vaccination reduced the infection rate by 89%; (iii) a large number of women took antiviral drugs before symptom onset after close contact with an infected person; and (iv) approximately 90% of hospitalized pregnant patients took antiviral drugs within 48 hours after symptom onset.     

Malignant pleomorphic adenoma (malignant mixed tumor) of the trachea. Report of a case

Malignant pleomorphic adenoma arising in the trachea has not been reported in the literature. We report here a case of malignant pleomorphic adenoma (malignant mixed tumor) occurring in the trachea of a 65-year-old woman. The tumor metastasized to the lung and the chest wall 11 years after complete resection of the primary tumor, which was a polypoid submucosal tumor, 1.3 cm in diameter. Light microscopic examination of the primary and metastatic tumors showed the presence of epithelial and stromal elements, consisting of grandular structures, foci of squamous metaplasia and a myxochondroid stroma. Many tumor cells showed myoepithelial cell features by electron microscopy, and immunoreactivity for S-100 protein and GFAP was also seen in many of them. These findings were consistent with those of pleomorphic adenoma. However, the epithelial elements were cytologically atypical with prominent mitotic figures. Infiltration of the tumor cells into the surrounding soft tissue was also seen. No foci of benign pleomorphic adenoma were found in the primary tumor. These findings indicate that this tumor was not a carcinoma ex pleomorphic adenoma, but a true malignant pleomorphic adenoma (true malignant mixed tumor) of the trachea.     

Effect of the interval between onset of sustained fetal bradycardia and cesarean delivery on long-term neonatal neurologic prognosis

Objective

To examine the effect of the interval between onset of sustained fetal bradycardia and cesarean delivery on long-term neonatal neurologic prognosis.

Method

A retrospective observational case-series performed with patients who had sudden-onset and sustained (< 100 beats per minute) fetal bradycardia during labor. Fetal heart rate was monitored closely until cesarean delivery. The effect of the interval between the onset of bradycardia and delivery on neonatal neurologic prognosis was examined.

Results

Among 2267 deliveries in 2002-2003 at Kitasato University Hospital, 19 pregnancies met the inclusion criteria. Episodes of fetal bradycardia were due to umbilical cord prolapse (n = 5), placental abruption (n = 4), uterine rupture (n = 3), maternal respiratory failure (n = 1), and other causes (n = 6). Mean onset of fetal bradycardia to delivery interval (BDI) was 20.5 ± 8.9 minutes. Mean decision-to-cesarean delivery interval was 11.4 ± 3.9 minutes. BDI was negatively correlated with umbilical arterial pH at delivery. There were 3 postnatal deaths. Neurologic assessment at the age of 2 years revealed that 15 of 16 children were neurologically normal. When the BDI was less than 25 minutes, all term pregnancies led to normal neonatal neurologic development.

Conclusion

In the event of sustained intrapartum fetal bradycardia, delivery by emergency cesarean within 25 minutes improved long-term neonatal neurologic outcome.     

Hyperthermia reduces the occurrence of proliferative vitreoretinopathy in a rabbit model.

The effects of hyperthermia on experimental proliferative vitreoretinopathy (PVR) in rabbits were studied. Heat treatment (42.4 degrees C for 30 min) of the retinal surface (as estimated from temperature measurement of the retrobulbar space) 2 to 3 hr after fibroblast injection reduced the occurrence of traction retinal detachment compared with control rabbits (P less than 0.02), but the incidence of pucker formation plus traction detachment was not significantly different between the two groups. In a separate experiment, heat treatment applied to normal rabbit eyes showed only reversible elongation in the latency of the electroretinographic b-wave without affecting the amplitude. Histologic examination revealed no significant changes in the heat-treated normal rabbit retina. Hyperthermia may be used as a new therapeutic tool for PVR.     

Effect of teeth clenching on swallowing motor patterns in humans

The purpose of this study was to investigate the effect of teeth clenching on swallowing motor patterns. Seven healthy humans participated in this study. Electromyograms (EMGs) were recorded from the right masseter muscle, the suprahyoid muscles, and the right infrahyoid muscles. Three motor tasks were performed while the EMGs were recorded: swallowing without teeth clenching, and two tasks of swallowing with teeth clenching, one with masseter EMG activity at 20% of maximum, and one with masseter EMG activity at 40% of maximum. The duration of suprahyoid EMG activity with teeth clenching was significantly longer than that without teeth clenching. The duration of infrahyoid EMG activity with teeth clenching was significantly shorter than that without teeth clenching. The whole duration of swallowing with teeth clenching was significantly shorter than that without teeth clenching. Teeth clenching changes the swallowing motor pattern, indicating that activity of the masticatory center affects activity of the swallowing center.