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Biomedical subjects

J E Lynch

Publications and source records attributed to J E Lynch.

At least 19 recordsLinked to original sources
PubMed2001

Body image across the life span in adult women: the role of self-objectification.

This study aimed to investigate women's body image across the entire life span from within the theoretical perspective provided by objectification theory (B. L. Fredrickson & T.-A. Roberts, 1997). In a cross-sectional study, a sample of 322 women ranging in age from 20 to 84 years completed a questionnaire measuring body dissatisfaction, self-objectification, and its proposed consequences. Although body dissatisfaction remained stable across the age range, self-objectification, habitual body monitoring, appearance anxiety, and disordered eating symptomatology all significantly decreased with age. Self-objectification was found to mediate the relationship between age and disordered eating symptomatology. It was concluded that objectification theory helps clarify the processes involved in the changes in body image that occur with age.

Adult↗
PubMed1988

Consumer selection of physicians and dentists: an examination of choice criteria and cue usage.

If health care marketers can understand the criteria consumers use to evaluate them and can identify which cues are used to assess those criteria, they will be better able to manage and influence the consumers' evaluations and perceptions of their service offering. In an exploratory study, the authors examine the criteria and cues used by consumers in selecting physicians and dentists. Competence and courtesy are found to be the most important criteria. Personal referral cues emerge as often determinant in the initial selection of physicians and dentists. The actual interactive nature of the service encounter, however, determines continued consumer patronage.

Canada↗
PubMed1984

Evaluation of three 4"-deoxy-4"-sulfonamido-oleandomycin derivatives with erythromycin-like antibacterial potency.

Three derivatives of oleandomycin in which the C"-4 hydroxyl moiety was replaced for the first time with a nitrogen functionality have been compared with erythromycin base and oleandomycin base. The minimum inhibitory concentrations of these derivatives for 90% of a group of clinical isolates of Staphylococcus aureus were one-half to one-fourth those of erythromycin. The minimum inhibitory concentrations of the experimental macrolides for 50% of a group of S. aureus isolates resistant to greater than 12.5 micrograms of erythromycin per ml ranged from 0.2 to 0.39 micrograms/ml. The activities of these experimental compounds were equivalent to the activities of erythromycin against Staphylococcus epidermidis, Bacteroides fragilis, and Haemophilus influenzae isolates. In general, erythromycin was more active against Streptococcus species. Each experimental macrolide was superior to erythromycin in inhibiting RNA-directed, cell-free polypeptide synthesis. The three experimental compounds were markedly more active than erythromycin base after oral administration to mice infected with S. aureus. The 50% protective doses of the experimental compounds ranged from 27.4 to 45.7 mg/kg; that of erythromycin was approximately 100 mg/kg.

Animals↗
PubMed1983

Anticoccidial derivatives of 6-azauracil. 5. Potentiation by benzophenone side chains.

Attachment of p-benzophenone side chains at N1 was found to be one of the most effective modifications for enhancing the potency of 6-azauracil against a broad spectrum of coccidia in chickens. Compound 20 was about 1000-fold more potent than 6-azauracil. Structure-activity relationships paralleled those found in a previously reported series of related analogues containing diphenyl sulfide and sulfone side chains. Drug metabolism studies showed the ketones to be reduced rapidly to carbinols, which are the prevalent species in vivo.

Animals↗
PubMed1981

Anticoccidial derivatives of 6-azauracil. 4. A 1000-fold enhancement of potency by phenyl sulfide and phenyl sulfone side chains.

We report further progress in exploiting our earlier discovery that the anticoccidial activity of 6-azauracil increases markedly when appropriately substituted benzyl or phenyl groups are attached at N-1. With guidance from previous structure-activity relationships and a multiple linear regression analysis, 6-azauracils containing phenyl sulfone or phenyl sulfide side chains were prepared. These prevented a broad spectrum of coccidial infections in chickens at minimum inhibitory concentrations by weight in feed as low as 0.25 ppm, a 4000-fold increase in potency over 6-azauracil, and had shorter plasma half-lives than earlier potent analogues. Sulfides were more potent than sulfones, although they were oxidized rapidly to sulfones in vivo.

Animals↗
PubMed1980

Anticoccidial derivatives of 6-azauracil. 3. Synthesis, high activity, and short plasma half-life of 1-phenyl-6-azauracils containing sulfonamide substituents.

A series of 1-phenyl-6-azauracils containing sulfonamide substituents was prepared. In contrast to previous 1-phenyl-6-azauracils, some of these sulfonamides combine high activity against Eimeria tenella infections in chickens with a very rapid rate of clearance from plasma. Most active was 1-[3'-chloro-5'-methyl-4'-(morpholinylsulfonyl)phenyl]-6-azauracil, with a minimum effective concentration in feed of about 10 ppm.

Animals↗
PubMed1979

Anticoccidial derivatives of 6-azauracil. 2. High potency and long plasma life of N1-phenyl structures.

Attachment of substituted phenyl side chains at N1 of 6-azauracil caused striking increases in plasma life and anticoccidial potency. The increases were related in part to the acidity of the imide hydrogen. Maximum effects were shown by phenyl rings substituted in both meta positions by compact, electron-withdrawing, lipophilic substituents, as in 1-(3',5'-dichlorophenyl)-6-azauracil, which had plasma half-life of 160 h and a potency 250-fold greater than that of 6-azauracil.

Animals↗
PubMed1978

CP-45,899, a beta-lactamase inhibitor that extends the antibacterial spectrum of beta-lactams: initial bacteriological characterization.

CP-45,899 {3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 4,4-dioxide, [2S-(2alpha,5alpha)]} is an irreversible inhibitor of several bacterial penicillinases and cephalosporinases. In the presence of low concentrations of CP-45,899, ampicillin and other beta-lactams readily inhibit the growth of a variety of resistant bacteria that contain beta-lactamases. CP-45,899 used alone displays only weak antibacterial activity, with the notable exception of its potent effects on susceptible and resistant strains of Neisseria gonorrhoeae. CP-45,899 appears to be somewhat less potent but markedly more stable (in aqueous solution) than the recently described beta-lactamase inhibitor clavulanic acid. The spectrum extensions provided by the two compounds are similar. A 1:1 mixture of CP-45,899 and ampicillin displays marked antimicrobial activity in mice experimentally infected with ampicillin-resistant Staphylococcus aureus, Haemophilus influenzae, Klebsiella pneumoniae, and Proteus vulgaris.

Ampicillin↗
PubMed1977

Anticoccidial derivatives of 6-azauracil. 1. Enhancement of activity by benzylation of nitrogen-1. Observations on the design of nucleotide analogues in chemotherapy.

Benzylation of 6-azauracil at N-1 (which corresponds to the point of attachment of the ribose phosphate unit in pyrimidine nucleotides) has been found to augment its anticoccidial activity fourfold. The high potency of 1-benzyl-6-azauracil is ascribed to a combination of intrinsic activity, efficient oral absorption, and a moderate rate of excretion. Metabolism experiments using 1-benzyl-6-azauracil labeled with 14C in the heterocycle and (separately) in the side chain showed that, in the drug accounted for, no cleavage had occurred. Additional activity increases were achieved by introducing small, electron-withdrawing substituents in the meta and/or para position(s) of the benzyl group. One of the most active derivaties, 1-(3-cyanobenzyl)-6-azauracil, is about 16 times as potent as 6-azauracil.

Animals↗
PubMed1976

Laboratory evaluation of 3-(5-tetrazolyl) penam, a new semisynthetic beta-lactam antibacterial agent with extended broad-spectrum activity.

In the new agent 3-(5-tetrazolyl)penam, hereafter referred to as CP-35,587, the carboxyl function at C3 in the penicillin nucleus has been replaced with the 5-tetrazolyl moiety. Marked changes in spectrum and resistance to gram-negative beta-lactamases, particularly with regard to Klebsiella pneumoniae isolates, were conferred by this modification. The anti-Klebsiella activity clearly distinguishes the antibacterial spectrum of CP-35,587 from any known broad-spectrum penicillin. Compared to orally active cephalosporins, the spectrum advantage of CP-35,587 encompasses Enterobacter, Serratia marcescens, Citrobacter, Providencia, Haemophilus influenzae, and Streptococcus faecalis, both in vitro and in murine infections produced by many of the above-named microorganisms. Thus, CP-35,587 combines and extends the antibacterial activity of broad-spectrum penicillins and orally active cephalosporins.

Animals↗
PubMed1976

Influence of subtherapeutic levels of a combination of neomycin and oxytetracycline on Salmonella typhimurium in swine, calves, and chickens.

Subtherapeutic levels of oxytetracycline plus neomycin in animal feeds did not bring about increases in the quantity, prevalence, or shedding of Salmonella typhimurium in swine, calves, or chickens. In fact, the medication generally reduced the proportion of animals carrying S. typhimurium. The medicated groups were fed rations containing oxytetracycline plus neomycin commencing 5 days prior to oral inoculation with S. typhimurium and continuing through a 28-day postinoculation period. Colonization of S. typhimurium occurred in all three animal species, as evidenced by clinical signs of infection and/or colony counts in feces. Only from swine and on only one occasion was a single resistant colony isolated. It is concluded that no evidence has been obtained which would implicate the continuous low-level feeding of oxytetracycline and neomycin for a 4-week period to a potential increased incidence of disease in animals or as a hazard to humans.

Animals↗
PubMed1976

Laboratory studies with a new broad-spectrum penicillin, pirbenicillin.

Pirbenicillin {6-[d-2-phenyl-2(N-4-pyridylformimidoylaminoacetamido) -acetamido]-penicillanic acid} showed broad-spectrum antibacterial activity in vitro and also in the treatment of experimental infections after parenteral administration to mice. Against Pseudomonas aeruginosa, a three- to fourfold potency advantage over carbenicillin was seen both in vitro and in vivo. The in vitro antibacterial spectrum of pirbenicillin includes Escherichia coli, Serratia, Citrobacter, and Enterobacter isolates, against which it exhibited minimal inhibitory concentration values comparable to those of carbenicillin. However, mice infected with E. coli and Serratia were protected at doses of pirbenicillin that were two to four times lower than those required of carbenicillin. Pirbenicillin was more active than carbenicillin against gram-positive bacteria, especially Streptococcus faecalis. It was less active than carbenicillin against Proteus spp. and was inactive against ampicillin-resistant E. coli strains. Pirbenicillin was bactericidal at concentrations generally equal to or only two-fold higher than the minimal inhibitory concentration. With appropriately buffered media, pirbenicillin demonstrated eight- and fourfold better minimal bactericidal concentration values towards Pseudomonas isolates than those of carbenicillin and ticarcillin, respectively.

Anti-Bacterial Agents↗
PubMed1975

Influence of subtherapeutic levels of oxytetracycline on Salmonella typhimurium in swine, alves, and chickens.

Subtherapeutic levels of oxytetracycline in animal feeds have been evaluated to determine their influence on the relative quantity, prevalence, shedding, and antibiotic susceptibility of Salmonella typhimurium in swine, calves, and chickens, when compared with nonmedicated controls. The medicated groups were fed rations containing oxytetracycline commencing 5 days prior to oral inoculation with S. typhimurium and continuing through a 28-day post-inoculation period. Colonization of S. typhimurium occurred in all three animal species as evidenced by clinical signs of infection and/or colony counts in feces measured on seven separate occasions over the 28-day observation period. The accumulated data demonstrate that the subtherapeutic use of oxytetracycline did not bring about any increases in the quantity, prevalence, or shedding of S. typhimurium in swine, calves, and chickens. In fact, the medication generally brought about a decrease in the percentage of animals carrying S. typhimurium during the study period. In contrast to results in swine and calves, there was a significant occurrence of S. typhimurium resistance to oxytetracycline in chickens. Resistant colonies were isolated from chickens sporadically but never on more than two consecutive test periods. These isolates were also resistant to streptomycin, but not to the other six antibiotics tested. The population of resistant S. typhimurium isolated from medicated chickens was no larger than that of susceptible S. typhimurium isolated from the nonmedicated animals. It is concluded that no evidence has been obtained which would relate the continuous low-level feeding of oxytetracycline for a 4-week period to an increased incidence of disease in animals or as a hazard to humans.

Animals↗
PubMed1972

Carbenicillin indanyl sodium, an orally active derivative of carbenicillin.

Carbenicillin indanyl sodium, an orally active derivative of carbenicillin, is active against a broad spectrum of bacterial species. Although the ester has in vitro antimicrobial activity per se when evaluated in Brain Heart Infusion broth, the in vivo antibacterial activity seen in mice and rats reflects primarily the efficient hydrolysis of the ester to carbenicillin. With an acute systemic infection in mice as a test system, orally administered carbenicillin indanyl sodium protected mice against lethal infections produced by Escherichia coli, Salmonella choleraesuis, Pasteurella multocida, Proteus vulgaris, Staphylococcus aureus, and Streptococcus pyogenes. The dose that protected 50% of the animals against each of these infections was comparable to that of parenteral carbenicillin. Against experimental urinary-tract disease in rats produced by E. coli, P. vulgaris, and Pseudomonas aeruginosa, it was again observed that carbenicillin indanyl sodium provided activity comparable to that of parenterally administered carbenicillin.

Animals↗