Author: Fan, Jing ; Wang, Panlin ; Shi, Lei ; Xu, Hong ; Chen, Jilan ; Li, Yunlei ; Liu, Yifan ; Ni, Aixin ; Huang, Ziyan ; Chen, Chao ; Ma, Hui ; Li, Dongli ; Sun, Yanyan

The objective of this study was to determine the effect of age at photostimulation on sexual maturity and performance of layer breeders. A total of 192 fourteen-wk-old White Leghorn (WL) breeder hens were randomly allocated to 4 treatments of 48 birds each, with 2 replicates per treatment. The birds were photostimulated at 16 (PS16), 18 (PS18), 20 (PS20), and 22 (PS22) wk of age. Four birds per treatment were randomly selected to evaluate sexual organ development at 1 D before photostimulation and 2, 4, and 6 wk after photostimulation. The ovary weight, large yellow follicles number (LYF), oviduct weight, and oviduct length of PS18 increased sharply after photostimulation. Conversely, the increase in PS16 was not observed until 2 wk after photostimulation. There was no difference in age at sexual maturity between treatments (P > 0.05). The PS16 had the longest interval (28 D) from photostimulation to 5% egg production, while PS22 reached 5% egg production 7 D before photostimulation. The PS22 had lower peak production (P = 0.02) and less egg production (P = 0.02) than other treatments. The PS16 had more broken and abnormal eggs (P = 0.01) and lower hatchability (P = 0.04) than other treatments. In conclusion, photostimulation at 16 and 22 wk of age decreases hatchability and egg production, respectively, and photostimulation at 18 wk is appreciated for the WL breeder hens.

01 Mar 2003·Antimicrobial Agents and Chemotherapy

Enhanced In Vitro Activity of Dihydrofolate Reductase and Dihydropteroase Synthase Inhibitors in Combination against Nocardia spp

Letter

Author: Yeo, Anthony E. T. ; Destefano, Michelle S. ; Cynamon, Michael H. ; Thielking, Deborah M.

Common treatments for nocardial infections include the sulfonamides used alone or in combination, e.g., trimethoprim-sulfamethoxazole, with amikacin, imipenem, or ceftriaxone. Treatment is especially difficult in cases involving the central nervous system or disseminated disease or with drug-resistant species such as Nocardia farcinica and Nocardia otitidiscaviarum (5). Sulfamethoxazole and dapsone inhibit dihydropteroate synthase and hence prevent the conversion of bacterial para-aminobenzoic acid to dihydrofolic acid. The active putative metabolite of PS-22 is a dihydrotriazine, a sister compound of WR99210 (1). WR99210 is a dihydrofolate reductase inhibitor that has demonstrated in vitro activity against Nocardia species (3). Theoretically, the combination of a dihydrofolate reductase inhibitor with a dihydropteroate synthase inhibitor should lead to enhanced activity, as both these enzymes lie on the folate biosynthesis pathway. This was evaluated in vitro. The active putative metabolite of PS-22 and dapsone was provided by Jacobus Pharmaceutical Co., Princeton, N.J.; sulfamethoxazole was purchased from Sigma Chemical Co., St. Louis, Mo. Twenty strains of Nocardia spp. from the American Type Culture Collection and clinical isolates provided by the Clinical Microbiology Laboratory, Upstate Medical University (Betty Ann Forbes), Syracuse, N.Y., were used in this study. Experimental in vitro procedures were modeled after those listed in the paper of Meyer et al. (4). Varying concentrations of the active putative metabolite of PS-22 were tested against fixed concentrations of sulfamethoxazole and dapsone. The concentration of sulfamethoxazole at 10 μg/ml was physiologically achievable. The concentration of dapsone was fixed at 1 μg/ml, as following the administration of 100 mg of the drug orally serum drug concentrations range from 0.4 to 1.2 μg/ml (2). Table Table11 shows the results of the drug combinations against various Nocardia species. The in vitro activity of the active putative metabolite of PS-22 was generally enhanced by combination with dapsone or sulfamethoxazole. These results agree with the findings of McNeil et al. (3) and demonstrate that the rational drug combination of a dihydrofolate reductase inhibitor combined with a dihydropteroate synthase inhibitor provides good targets for the evaluation of agents that work at these sites. TABLE 1. MICs (μg/ml) of a WR99210 analogue alone and in combination with dapsone or sulfamethoxazole against various strains of Nocardia spp.

100 Deals associated with PS-22

R&D Status

10 top R&D records.

to view more data

Indication	Highest Phase	Country/Location	Organization	Date
Malaria	Discovery	US	Jacobus Pharmaceutical Co., Inc.	-

Clinical Result

Indication

Phase

Evaluation

View All Results

Translational Medicine

Boost your research with our translational medicine data.

view full example data

Deal

Boost your decision using our deal data.

view full example data

Core Patent

Boost your research with our Core Patent data.

view full example data

Clinical Trial

Identify the latest clinical trials across global registries.

view full example data

Approval

Accelerate your research with the latest regulatory approval information.

view full example data

Regulation

Understand key drug designations in just a few clicks with Synapse.

view full example data

Chat with Hiro

Get started for free today!

Accelerate Strategic R&D decision making with Synapse, PatSnap’s AI-powered Connected Innovation Intelligence Platform Built for Life Sciences Professionals.

Start your data trial now!

Synapse data is also accessible to external entities via APIs or data packages. Empower better decisions with the latest in pharmaceutical intelligence.

Bio

Bio Sequences Search & Analysis

Chemical

Chemical Structures Search & Analysis


No Data

PS-22

Overview

Basic Info

Related

R&D Status

Clinical Result

Translational Medicine

Deal

Core Patent

Clinical Trial

Approval

Regulation