A newly developed fluoroquinoline, Q-35 (8-OCH3), in which a methoxy group was substituted at the 8 position of the quinoline nucleus, was very stable under irradiation with long-wave UV light (UVA). Derivatives, a fluoroquinolone with no substitution (the 8-H analog) and one in which a fluorine was substituted (the 8-F analog), were degraded in their solutions by the UVA irradiation. The phototoxic inducibility by these derivatives was further studied in a murine model. When mice were dosed orally with 800 mg of Q-35 (8-OCH3) per kg of body weight, the maximum dose given, and exposed to the UVA light, no inflammatory lesions were observed in their ears. Ear redness was marked in mice given more than 12.5 mg of the 8-F analog or 200 mg of the 8-H analog per kg. Histopathological changes, edema, and infiltration of neutrophils were also observed microscopically in groups receiving the 8-H or 8-F analog but not in groups receiving Q-35 (8-OCH3). Similar inflammatory reactions were observed to occur in a dose-dependent manner with other available fluoroquinolone antibacterial agents such as lomefloxacin, enoxacin, norfloxacin, ciprofloxacin and ofloxacin. These results suggest that the introduction of a methoxy group at the 8 position of the quinolone nucleus is important for the reduction of phototoxicity.

TLR4 and MD-2 may mediate OK-432-induced anticancer immunity.

Q-35 [1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-(3-methylaminopiperidine-1-yl)-4-oxoquinoline-3-carboxylic acid], a fluoroquinolone, has absorbance peaks at 333 and 286 nm. No spectral change was observed even when this aqueous solution was irradiated with 3 J of long-wavelength UV light (UVA) per cm2. On the other hand, its derivatives, which are unsubstituted (8-H analog) or which are substituted with fluorine at the 8 position (8-F analog), were found to have decreased antibacterial activities with a simultaneous increase in their cytotoxicities when they were degraded in a dose-dependent manner with respect to UVA irradiation. Similar results were observed with the other available fluoroquinolones. Enoxacin and lomefloxacin exposed to 0.3 J of irradiation per cm2 and norfloxacin, ofloxacin, and ciprofloxacin exposed to 1 J of irradiation per cm2 underwent absorption spectrum changes, an accompanying decrease in antibacterial activity, and an increase in cytotoxic activity. These results suggest that the introduction of a methoxy group into the 8 position of quinolones plays an important role in the stability of fluoroquinolones against irradiation by UV light.

Protective effect of recombinant human granulocyte colony-stimulating

A purified human granulocyte colony-stimulating factor (hG-CSF) was studied for its protective effect on the induction of neutropenia and enhanced susceptibility to microbial infections in mice receiving cyclophosphamide (CPA). A severe reduction in peripheral blood nteutrophils was induced 4 days after injection with 200 mg of CPA per kg although the level normalized rapidly thereafter. When mice were injected subcutaneously once a day with 2.5 ,ug of hG-CSF beginning on the day after CPA injection, the reduction was prevented markedly, even 4 days later. On the other hand, in mice receiving CPA 4 days prior to infection, a weakened resistance to intraperitoneal challenge with a strain of Pseudomonas aeruginosa was induced. This weakened resistance was dose-dependently restored to normal by four daily injections with hG-CSF. A daily dose of 1.0 ,ug was required for complete restoration, although hG-CSF did not directly inhibit bacterial growth in vitro. In hG-CSF-treated mice, morphologically mature neutrophils migrated rapidly into the peritoneal cavities where bacteria were inoculated, followed by a rapid elimination of bacteria from the locality as compared with controls. In addition, the same treatment with hG-CSF was able to protect significantly against systemic infections caused by Serratia marcescens, Escherichia coli, Staphylococcus aureus, and Candida albicans. These data show the possibility that prophylactic therapy with hG-CSF may augment the resistance of immunocompromised patients to infections.

No abstract

Tissue-specific stem cells give rise to new functional cells to maintain tissue homeostasis and restore damaged tissue after injury. To ensure proper brain functions in the adult brain, neural stem cells (NSCs) continuously generate newborn neurons that integrate into pre-existing neuronal networks. Proliferation, as well as neurogenesis of NSCs, are exquisitely controlled by extrinsic and intrinsic factors, and their underlying mechanisms have been extensively studied with the goal of enhancing the neurogenic capacity of NSCs for regenerative medicine. However, neurogenesis of endogenous NSCs alone is insufficient to completely repair brains damaged by neurodegenerative diseases and/or injury because neurogenic areas are limited and few neurons are produced in the adult brain. An innovative approach towards replacing damaged neurons is to induce conversion of non-neuronal cells residing in injured sites into neurons by a process referred to as direct reprogramming. This review describes extrinsic and intrinsic factors controlling NSCs and neurogenesis in the adult brain and discusses prospects for their applications. It also describes direct neuronal reprogramming technology holding promise for future clinical applications.

Linkage between early-life exposure to anesthesia and subsequent learning disabilities is of great concern to children and their families. Here we show that early-life exposure to midazolam (MDZ), a widely used drug in pediatric anesthesia, persistently alters chromatin accessibility and the expression of quiescence-associated genes in neural stem cells (NSCs) in the mouse hippocampus. The alterations led to a sustained restriction of NSC proliferation toward adulthood, resulting in a reduction of neurogenesis that was associated with the impairment of hippocampal-dependent memory functions. Moreover, we found that voluntary exercise restored hippocampal neurogenesis, normalized the MDZ-perturbed transcriptome, and ameliorated cognitive ability in MDZ-exposed mice. Our findings thus explain how pediatric anesthesia provokes long-term adverse effects on brain function and provide a possible therapeutic strategy for countering them.