PubMed Health⌕ Search

Biomedical subjects

E Akin

Publications and source records attributed to E Akin.

17 recordsLinked to original sources
PubMed1999

In vitro antimicrobial activity of silicone oil against endophthalmitis-causing agents.

PURPOSE: To investigate the antimicrobial activity of silicone oil against endophthalmitis-causing agents in vitro. METHODS: The antimicrobial activity of silicone oil was tested on Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Candida albicans, and Aspergillus spp. The bacteria and fungi were separately inoculated into 1,300 centistokes silicone oil. Control inoculations were done in two different media: physiologic saline and brain-heart infusion (BHI) for bacteria and Sabouraud broth and physiologic saline for fungi. From each medium, 0.001-mL samples were taken and plated in Petri dishes. After overnight incubation, colony-forming units (CFUs) were enumerated. Culturing from the initially prepared specimens, incubating overnight, and counting CFUs was repeated until no growth of microorganisms was seen in the silicone oil-containing media. Macroscopic photography of the colonies and light microscopic photography of microorganisms were performed. RESULTS: All the microorganisms showed an apparent decrease in CFUs, with elimination between 7 and 21 days in silicone oil. Colony-forming units of microorganisms remained stable in physiologic saline during the study, with the exception of gradual decrease in CFUs of S. aureus and S. epidermidis from the beginning of the third day. In BHI and Sabouraud broth, both bacteria and fungi showed a growth pattern that was compatible with the growth curve of microorganisms. CONCLUSION: Silicone oil has an antimicrobial activity against S. aureus, S. epidermidis, P. aeruginosa, C. albicans, and Aspergillus spp., which are common endophthalmitis-causing agents.

Bacteria↗
PubMed1999

The immunoglobulin (IgG) antibody response to OspA and OspB correlates with severe and prolonged Lyme arthritis and the IgG response to P35 correlates with mild and brief arthritis.

In an effort to implicate immune responses to specific Borrelia burgdorferi proteins that may have a role in chronic Lyme arthritis, we studied the natural history of the antibody response to B. burgdorferi in serial serum samples from 25 patients monitored throughout the course of Lyme disease. In these patients, the immunoglobulin G (IgM) and IgG antibody responses to 10 recombinant B. burgdorferi proteins, determined during early infection, early arthritis, and maximal arthritis, were correlated with the severity and duration of maximal arthritis. The earliest responses were usually to outer surface protein C (OspC), P35, P37, and P41; reactivity with OspE, OspF, P39, and P93 often developed weeks later; and months to years later, 64% of patients had responses to OspA and OspB. During early infection and early arthritis, the levels of IgG antibody to P35 correlated inversely with the subsequent severity or duration of maximal arthritis. In contrast, during periods of maximal arthritis, the levels of IgG antibody to OspA and OspB, especially to a C-terminal epitope of OspA, correlated directly with the severity and duration of arthritis. Thus, the higher the IgG antibody response to P35 earlier in the infection, the milder and briefer the subsequent arthritis, whereas during maximal arthritis, the higher the IgG response to OspA and OspB, the more severe and prolonged the arthritis.

Adolescent↗
PubMed1987

A theory of follicle selection: I. Hypotheses and examples.

A theory of follicle selection is developed in which all follicles, ovulatory and atretic, inherit the same developmental plan for responding to circulating concentrations of estradiol and gonadotropins. In the model, this plan is represented by a maturation surface that determines the rate of follicle growth as a function of follicle maturity and circulating hormone concentration. Examples of maturation surfaces are constructed for single and multiple spontaneous ovulators. When model follicles are activated from the reserve pool at random times, spontaneous and coordinated cycles of maturation develop in which the number of ovulatory follicles is controlled within a small and predictable range. For a given maturation surface, this range is nearly independent of the number of follicles in the interacting population, their activation times, and their initial maturities. The theory is therefore consistent with Lipschütz's Law of Follicular Constancy. The theory can account for certain statistical effects that occur with age on the timing of ovulation and the control of ovulation number. Maturation surfaces are also constructed that exhibit spontaneous transitions from cyclic to steady anovulatory behavior. The theory predicts an important regulatory role for atretic follicles in controlling both the timing of maturation and the number of follicles that reach ovulatory maturity.

Computer Graphics↗
PubMed1987

A theory of follicle selection: II. Computer simulation of estradiol administration in the primate.

A theory of follicle selection (Lacker, 1981) is tested in the primate by simulating the effects of estradiol administration at different times, strengths, and durations during the follicular phase of the menstrual cycle (Clark et al., 1981; Zeleznik, 1981; Dierschke et al., 1985). The theory can account for the observed atretogenic effects of circulating estradiol on follicle development including full, partial, and delayed atresia of the dominant follicle (Dierschke et al., 1985) and can explain why similar estradiol doses achieve different qualitative effects when given at different times during the cycle. The theory predicts that recovery from early atresia may be possible, and it can also account for the loss of control in the number of maturing follicles that has been observed when estradiol antibodies are given in the midfollicular phase (Zeleznik et al., 1985). These results support the hypothesis that the selection mechanism in the primate is a consequence of feedback involving an essentially equipotent follicle population interacting through circulating estradiol and pituitary gonadotropins. A quantitative test of the theory awaits experimental identification of the maturation surfaces that are predicted by it. An experimental design for this purpose is proposed.

Animals↗
PubMed1986

Evolutionary games and two species population dynamics.

Competition between species has long been modeled by population dynamics based on total numbers of each species. Recently, the evolution of strategy frequencies has been used successfully for competition models between individuals. In this paper, we illustrate that these two views of competition are compatible. It is shown that the rate of intra and interspecific competitions between individuals largely determines the population dynamics. Competition models over a single common resource and predator-prey models are developed from this individual competition approach. In particular, the equilibrium strategies in a co-evolving predator-prey system are shown to be more stable than the predicted strategy cycling of standard evolutionary game theory.

Animals↗
PubMed1984

Evolutionary dynamics of zero-sum games.

Aim model in terms of differential equations is used to explain mammalian ovulation control, in particular regulation for a prescribed number of mature eggs.

Female↗
PubMed1984

Round robin investigation of methods for the recovery of poliovirus from drinking water.

Six laboratories actively involved in water virology research participated in a methods evaluation study, conducted under the auspices of the American Society for Testing and Materials Committee on Viruses in the Aquatic Environment, Task Force on Drinking Water. Each participant was asked to examine the Viradel (virus adsorption-elution) method with cartridge-type Filterite filters for virus adsorption and organic flocculation and aluminum hydroxide-hydroextraction for reconcentration. Virus was adsorbed to filter media at pH 3.5 and eluted with either glycine buffer (pH 10.5) or beef extract-glycine (pHG 9.0). Considerable variation was noted in the quantity of virus recovered from four 100-liter samples of dechlorinated tapwater seeded with low (350 to 860 PFU) and high (1,837 to 4,689 PFU) doses of poliovirus type 1. To have a more uniform standard of comparison, all the test samples were reassayed in one laboratory, where titers were also determined for the virus seed. Test results of the Viradel-organic flocculation method indicated that the average percentage of virus recovery for low-input experiments was 66%, with a range of 8 to 20% in two laboratories, 49 to 63% in three laboratories, and 198% in one laboratory. For the high-input experiments, two laboratories reported recoveries of 6 to 12%, and four laboratories reported recoveries of 26 to 46%. For the Viradel aluminum hydroxide-hydroextraction procedure, two laboratories recovered 9 to 11%, whereas four obtained 17 to 34% for low-input experiments. For the high-input tests, two laboratories reported a recovery of 3 to 5%, and four recovered 11 to 18% of the seeded virus.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum Hydroxide↗