Studies on bactericidal activities of beta-lactam antibiotics on agar plates: the correlation with the antibacterial activities determined by the conventional methods

A simplified method to determine minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of beta-lactam antibiotics on agar plates is described. MIC values were determined on agar plates for benzylpenicillin, methicillin and cephalothin using Staphylococcus aureus and Klebsiella pneumoniae. A beta-lactamase solution was then sprayed onto the plates to inactivate the drug(s). After further incubation at 37 degrees C overnight, the minimal concentration at which no test bacteria were visible on the plates was defined as MBC. Both MIC and MBC values decreased with decreased inoculum size. The two values were almost coincidental when high dilutions were used as the inocula. These values were compared with those obtained by the conventional broth dilution method. In this study, MIC as well as MBC values determined by the simplified method were generally smaller than the values determined by the broth dilution technique.     

clinical study of balofloxacin on infectious enteritis and assessment of the fecal drug concentration and intestinal microbial flora in patients with inpatients with infectious enteritis. Research group of balofloxacin on infectious enteritis

The efficacy, safety and usefulness of balofloxacin (BLFX) for patients with acute infectious enteritis and the carriers mainly shigellosis, were investigated. The drug was administered at a daily dose of 200 mg twice a day for 3 days to patients with cholera, 7 days to patients with Salmonella enteritis and 5 days to patients with other conditions of infectious enteritis including shigellosis; 1. The efficacy was analyzed in 89 of the 135 patients who received the administration (43 patients with shigellosis, 14 with Salmonella enteritis, 8 with enteropathogenic/ enterotoxigenic Escherichia coli enteritis, 3 with cholera, 7 with enteritis with other pathogenic bacteria, 6 with polymicrobial infectious enteritis and 8 with acute enteritis that was pathogen-negative). 2. In patients bearing symptoms and who thus could be analyzed for drug efficacy, the drug was markedly effective or effective 50/52 (96.2%). 3. Bacteriologically, the drug was effective for Shigella spp. in 41 (100%) of 41, Salmonella spp. in 12 (85.7%) of 14, and enteropathogenic/enterotoxigenic Escherichia coli in 8 of 8 cases. 4. Adverse effects were seen in 5/133 patients (3.8%) receiving the drug, including two cases of skin eruption, one of the numbness of the hands, one of oral aphtha, and one of nausea. In patients for whom laboratory findings were available, 20/115 (17.4%) showed abnormalities, mainly elevations of GOT and/or GPT, but these were slight. 5. In terms of subjective reports of usefulness, 51/82 (62.2%) were markedly satisfied, and 73/82 (89.0%) were either satisfied or markedly satisfied. 6. The influence of administration of BLFX on fecal concentration and intestinal microbial flora was investigated in 2 patients with acute infectious enteritis. Results approximately equivalent to such flora levels in healthy subjects were obtained. These results suggest that BLFX is highly useful for infectious enteritis such as that caused by shigellosis.     

Scintillation yields by relativistic heavy ions and the relation between ionization and scintillation in liquid argon

Scintillation yields per unit energy deposited by relativistic heavy ions in liquid argon have been measured. They are (1.41 ± 0.07) for 613 MeV/n Ne ions and (1.39 ± 0.07) for 705 MeV/n Fe ions, if the value is normalized to unity for 5.3 MeV alpha particles. These results show that the scintillation intensity for relativistic heavy ions in liquid argon is proportional to the deposited energy, that is, to Z₁², where Z₁ is the nuclear charge of heavy ions. Furthermore, the variation of ionization and scintillation in liquid argon has been investigated as a function of electric field using relativistic Ne and Fe ions. It is shown that a linear combination of ionization signal I and scintillation signal S, I + aS, is proportional to the deposited energy, independently of electric field strength and types of incident particles. This suggests that if we use both signals, we may construct a massive calorimeter that can be used for nuclear reactions induced by relativistic heavy ions.     

Synthesis of a cis-rich,living poly[(o-methylphenyl)acetylene] by use of the MoOCl4-n-Bu4Sn-EtOH catalyst

Summary Polymerization of (o-methylphenyl)acetylene (o-MePA) by MoOCl₄-n-Bu₄Sn-EtOH catalyst in toluene at 0°C provided a cis-rich living polymer; cis 77%, M _w/M _n=1.21. The polymerization at -30°C gave results similar to those for 0°C, whereas the polymer obtained at 30°C exhibited a broader molecular weight distribution (MWD) and a lower cis content. Among several organotin compounds, only n-Bu₄Sn was effective for the living polymerization of o-MePA. The bulkier the alkyl group of alcohols as the third catalyst component, the broader the MWD of the polymer, while the geometrical structure was not affected by the alcohols.     

Surfactant‐Assisted Preparation of Novel Layered Silver Bromide‐Based Inorganic/Organic Nanosheets by Pulsed Laser Ablation in Aqueous Media

A novel layered AgBr‐based inorganic/organic nanocomposite was prepared by pulsed laser ablation (PLA) of Ag in aqueous media in the presence of cetyltrimethylammonium bromide (CTAB), and the formation mechanism of two‐dimensional nanosheet was discussed. TEM observations indicate that the obtained AgBr‐based inorganic/organic nanocomposite possesses a well‐defined two‐dimensional shape and that the size of the nanosheet can be changed with the surfactant concentration in the solution. X‐ray diffraction (XRD) pattern was composed of a series of peaks that could be indexed to (00l) reflections of a layered structure, and the basal spacing of 20.0 Å indicated that the surfactant was included between the AgBr interlayers in an interdigitated bilayer arrangement. In contrast, a layered inorganic/organic nanocomposite cannot be formed at a CTAB concentration lower than the critical micelle concentration (CMC). Based on our detailed investigation, we proposed the nanocomposite formation process, that is, that negatively charged inorganic AgBr was produced by a strong reaction between the ablated Ag species and the bromide ions, which are concurrently assembling with cationic surfactant molecules controlled by the charge‐matching mechanism.     

Mild synthesis of a CuSr2(Y,Ca) Cu2O y superconductor using a sol-gel method

A CuSr₂(Y, Ca) Cu₂O _y superconductor was obtained under atmospheric pressure using a sol-gel method. A material including this superconductive phase showed diamagnetic behaviour from 45 K and a drastic decrease of resistance from 51 K. It was found from X-ray diffraction and high-resolution transmission electron microscopy studies that the superconductive crystal has a tetragonal symmetry of a=0.382 nm and c=1.129 nm, and no superstructural ordering was found. However, we cannot completely rule out the possibility of carbon contamination on copper sites. It has been demonstrated that the sol-gel method is a promising route to synthesize high pressure phases of cuprate superconductors.     

High pressure synthesis of orthorhombic SnO2

A dense form of SnO₂ with an orthorhombic structure has been synthesized at 158 kbar and 800 °C. The boundary separating the normal pressure phase (tetragonal SnO₂-I) from the high pressure phase (orthorhombic SnO₂-II) is represented by P(kbar) = 140.0 + 0.022 T(°C). The lattice parameters of the quenched high pressure phase (SnO₂-II) are : $\text{a}\text{= 4.714 ± 0.001}\text{A}\text{?}$, $\text{b}\text{= 5.727 ± 0.001}\text{A}\text{?}$ and $\text{c}\text{= 5.214 ± 0.001}\text{A}\text{?}$ with the cell volume $\text{V}\text{= 140.8 ± 0.1}\text{A}\text{?}{}^3$. The volume decrease for the transition is calculated to be 1.8 %.     

Diffusion and intermolecular reaction rates of end-labeled polystyrenes in polymer networks studied with triplet probe

Summary The effect of chemical network on the diffusion and reaction rates of end-labeled polystyrenes in semidilute region has been measured by phosphorescence quenching technique with a 10-ns nitrogen-laser pulse, and is discussed in comparison with the results for linear polystyrene solution. The quenching rates between end-labeled polymers in semidilute region are influenced much by the formation of chemical crosslinks between the inert polymer chains.Presented at the 7th IUPAC Discussion Conference Polymer Networks, Karlovy Vary, CSSR, September 1980     

Administration of phosphatidylcholine increases brain acetylcholine concentration and improves memory in mice with dementia

Studies on the effect of phosphatidylcholine administration on memory are limited. We administered egg phosphatidylcholine to mice with dementia and to normal mice and compared the differences in memory and serum choline concentration, and choline and acetylcholine concentrations and choline acetyltransferase activities of three forebrain regions (cortex, hippocampus and the remaining forebrain). Mice with dementia were produced by mating sibling mice who had impaired memory for > 20 generations. These mice had poor memory and low brain acetylcholine concentration. We administered 100 mg of egg phosphatidylcholine (phosphatidylcholine group) or water (control group) by gavage to each mouse daily for about 45 d. Control mice with dementia had poorer memory in passive avoidance performance and lower brain choline (cortex and hippocampus) and acetylcholine (hippocampus and forebrain excluding cortex and hippocampus) concentrations and lower cortex choline acetyltransferase activity than the control normal mice (P < 0.05). The administration of phosphatidylcholine to mice with dementia improved memory and generally increased brain choline and acetylcholine concentrations to or above the levels of the control normal mice. In normal mice, phosphatidylcholine treatment did not affect memory or acetylcholine concentrations in spite of the great increase in choline concentrations in the three brain regions. Serum choline concentration in mice treated with phosphatidylcholine increased to a similar level in both strains of mice, indicating that the absorption of phosphatidylcholine was not impaired in mice with dementia. The results suggest that administration of egg phosphatidylcholine to mice with dementia increases brain acetylcholine concentration and improves memory.