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Biomedical subjects

L A Wilson

Publications and source records attributed to L A Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1993

Changes in keratometric astigmatism after suture removal more than one year after penetrating keratoplasty.

BACKGROUND/PURPOSE: Selective removal of interrupted sutures and adjustment of a running suture can minimize astigmatism after penetrating keratoplasty, but the long-term effects of early suture manipulations remain largely unknown. The authors tested the hypothesis that the cornea becomes "fixed" more than 1 year after keratoplasty so that desirable refractive results will remain when all sutures are eventually removed. METHODS: The authors reviewed retrospectively the changes in astigmatism that occurred when all remaining sutures were removed from 162 eyes 1 to 6 years after penetrating keratoplasty. Single-running sutures were used in 130 eyes, double-running sutures in 20 eyes, and a combination of interrupted and running sutures in 12 eyes. RESULTS: Removal of single-running sutures caused an average decrease in astigmatism of 0.52 diopters (D) from 6.10 +/- 4.41 D to 5.57 +/- 3.14 D. However, the astigmatism in 62% of eyes changed 2 or more D (range, 11.94 to -17.87 D), and the range changed more than 20 degrees in 55% of eyes. The average vectorial change was 6.5 +/- 4.3 D (range, 0.59 to 19.8 D). There was no decrease in the amount of astigmatic change with increasing time between surgery and suture removal. Graft size and diagnosis had no effect on the amount of astigmatic change. Astigmatic errors became stable, with less than 1 D of change between successive examinations within 6 months after suture removal. Similar results were obtained for eyes with double-running and interrupted-running sutures. CONCLUSIONS: Corneal astigmatism may change unpredictably and by large amounts when all remaining sutures are removed 1 to 6 years after penetrating keratoplasty.

Astigmatism↗
PubMed1993

Adaptation and growth of Serratia marcescens in contact lens disinfectant solutions containing chlorhexidine gluconate.

Serratia marcescens (11 of 12 strains) demonstrated an ability to grow in certain chlorhexidine-based disinfecting solutions recommended for rigid gas-permeable contact lenses. For a representative strain, cells that were grown in nutrient-rich medium, washed, and inoculated into disinfecting solution went into a nonrecoverable phase within 24 h. However, after 4 days, cells that had the ability to grow in the disinfectant (doubling time, g = 5.7 h) emerged. Solutions supporting growth of S. marcescens were filter sterilized. These solutions, even after removal of the cells, showed bactericidal activity against Pseudomonas aeruginosa and a biphasic survival curve when rechallenged with S. marcescens. Adaptation to chlorhexidine by S. marcescens was not observed in solutions formulated with borate ions. For chlorhexidine-adapted cells, the MIC of chlorhexidine in saline was eightfold higher than that for unadapted cells. Cells adapted to chlorhexidine showed alterations in the proteins of the outer membrane and increased adherence to polyethylene. Cells adapted to chlorhexidine persisted or grew in several other contact lens solutions with different antimicrobial agents, including benzalkonium chloride.

Adaptation, Biological↗
PubMed1992

The PIQ greater than VIQ discrepancy in violent and nonviolent delinquents.

This study found that approximately 35% of 149 juveniles convicted of serious crimes obtained a statistically significant PIQ greater than VIQ discrepancy of at least 12 IQ points. There were no significant differences in the incidence of the PIQ greater than VIQ discrepancy between juveniles convicted of violent or nonviolent crimes. The PIQ greater than VIQ discrepancy was found among both White and minority youth and among youth tested with either the WISC-R or the WAIS-R. IQ scores were correlated negatively with prior school problems, but not with measures of family dysfunction, prior criminal activity, or substance abuse. The PIQ greater than VIQ discrepancy appears to be an important indication of intellectual deficit in many delinquent youth.

Adolescent↗
PubMed1992

Hemagglutination (fimbriae) and hydrophobicity in adherence of Serratia marcescens to urinary tract epithelium and contact lenses.

The capacity of 59 isolates of Serratia marcescens, obtained from urinary tract infections, wounds, and contact lenses or their paraphernalia, to agglutinate erythrocytes from different animal species was tested. Three main patterns were found: mannose-sensitive agglutination of guinea-pig, fowl or horse erythrocyte; mannose-resistant agglutination of chicken or pigeon erythrocytes alone or in combination with mannose-sensitive agglutination; and no agglutination. Hemagglutination capacity was associated with isolates from urinary tract infection, but not with isolates associated with contact lenses. Adherence to human urinary tract epithelium did not correlate with the hemagglutination patterns nor with the origin of the isolates. Some strains of different hemagglutination pattern were selected for the study of hydrophobicity and adherence to contact lens polymers. Hydrophobicity, as determined by degree of partition in hexadecane and water (BATH-values), correlated neither with degree of adherence to contact lens polymers nor with the hemagglutination pattern. For a representative strain there was an excellent correlation (r2 = 0.98) between adherence and the water content (hydrophobicity) of the lens polymers. These results suggest that, as with tissues, other factors interact with hydrophobicity in causing adherence to plastics.

Alkanes↗
PubMed1992

Penetrating keratoplasty in patients with rheumatoid arthritis.

The authors reviewed in a retrospective manner 47 penetrating keratoplasties performed on 23 eyes of 21 patients with rheumatoid arthritis. The indications for the first penetrating keratoplasty were corneal melt in 19 eyes (83%), infectious keratitis in 2 eyes (9%), and corneal scarring after ulceration in 2 eyes (9%). Twelve of the 23 eyes required 24 repeat penetrating keratoplasties. Seventeen of the 23 eyes (74%) had clear grafts at the last follow-up visit, a median of 13.7 months after the last penetrating keratoplasty. The final best corrected visual acuity was greater than or equal to 20/60 in 4 eyes (17%), 20/70 to 20/100 in 1 eye (4%), 20/200 to 20/400 in 7 eyes (30%), counting fingers in 4 eyes (17%), hand motions in 2 eyes (9%), and light perception in 4 eyes (17%). One eye (4%) was enucleated. Anatomic success (absence of phthisis bulbi, enucleation, or conjunctival flap) was achieved in 20 eyes (87%). The survival probability for the 21 patients was only 48% 5 years after the first penetrating keratoplasty. The authors conclude that penetrating keratoplasty is often anatomically successful in patients with rheumatoid arthritis; however, the prognosis is poor for both vision and survival of the patient.

Adult↗
PubMed1992

Experimental regeneration in canine muscular dystrophy--1. Immunocytochemical evaluation of dystrophin and beta-spectrin expression.

The expression of dystrophin and beta-spectrin was examined from 1 to 56 days in regenerating muscle fibres in normal and dystrophic dogs, following necrosis induced by the venom of Notechis scutatis. Normal and dystrophic dog muscle regenerated at an equal rate and new myotubes were present in both at the periphery of necrotic fibres by 3 days. In normal dogs dystrophin was detected in the sarcoplasm of the regenerating fibres by 3 days and was localized to the plasma membrane by 4 days. The localization of dystrophin is independent of beta-spectrin and was detected before beta-spectrin, which was not observed until 5-6 days. Normal peripheral labelling of both was restored by 14 days in normal dogs. Normal beta-spectrin labelling of regenerating dystrophic fibres was also restored by 14 days and is not dependent on the presence of dystrophin in dystrophic dogs. A proportion of regenerating fibres in normal and dystrophic dogs showed weak immunolabelling of beta-spectrin prior to 14 days. This is a feature of immature muscle fibres. Antibodies to different domains of dystrophin bound to the periphery and sarcoplasm of regenerating fibres in dystrophic dogs, particularly during the first 7 days of regeneration, but the fluorescence was less intense than in normal dogs. Weak labelling with antibodies corresponding to the C-terminus of the rod domain of dystrophin persisted on dystrophic regenerating fibres up to 21 days. This may relate to developmental isoforms of dystrophin.

Animals↗
PubMed1992

Characterization of "modified-self"-induced specific antibody hyporesponsiveness to herpes simplex virus.

Pretreatment of mice iv with syngeneic spleen cells modified with soluble HSV envelope antigens induced an anti-HSV antibody hyporesponsiveness following challenge with infectious virus. The epitope density on the HSV-modified spleen cells was quantitated using a photon-counting spectrofluorimeter so that observed immunological results could be correlated with the HSV antigen dose on the splenocytes. The degree of anti-HSV antibody hyporesponsiveness was found to be related to the epitope density on the HSV-modified spleen cells, but not the number of modified cells used in the pretreatment over the 16-fold range tested. Anti-HSV antibody hyporesponsiveness was induced if 7, but not 3, days had elapsed between pretreatment and challenge. This antibody hyporesponsiveness could be adoptively transferred with T cells. Only mice that had induced an anti-HSV antibody hyporesponsiveness following pretreatment with HSV-modified splenocytes were able to survive an LD50 challenge with infectious virus.

Animals↗
PubMed1992

The structure and function of urban pharmacies: visits to community pharmacies in inner-city Chicago.

Visits were made to 21 pharmacies in two poor neighborhoods on the west side of Chicago and interviews conducted with pharmacists-in-charge. The objective of the study was to provide a comprehensive description of the function, capabilities, and problems of urban pharmacy. We present results on the structure and function of these inner-city pharmacies. The pharmacies fit one of three structural forms: chain, independent, or medical center. The majority of respondents viewed the function of the inner-city pharmacy as patient-centered but also identified several barriers to effective patient communication. The results suggest that inner-city physicians and pharmacists should communicate with patients more often and in ways that patients understand. Also, Medicaid and other drug insurance programs should develop patient information networks and coverage packages intended to maximize patient health status.

Chicago↗
PubMed1991

Comparative efficacies of soft contact lens disinfectant solutions against microbial films in lens cases.

Biofilms of Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus epidermidis, Streptococcus pyogenes, and Candida albicans, established in the wells of a polyethylene contact lens case, retained viability to certain soft contact lens disinfectant solutions after exposure for the manufacturer's minimum recommended disinfection times. The relative order of resistance of bacterial biofilms was as follows: S marcescens was greater than P aeruginosa, which was greater than S epidermidis, which was greater than S pyogenes. Air drying of biofilms for 10 hours increased the efficacy of the disinfectant solutions, but drying was not enough to decrease the incidence of recovery to 0% for all solutions. Hydrogen peroxide was more effective against biofilms than disinfectant solutions formulated with chlorhexidine gluconate or polyquaternium-1 or polyaminopropyl biguanide. We recommend that determination of efficacy of contact lens disinfectant solutions should include challenges against biofilms.

Bacteria↗
PubMed1991

Adherence of Pseudomonas aeruginosa to rigid gas-permeable contact lenses.

We examined the adherence of a human corneal isolate of Pseudomonas aeruginosa to unused rigid gas-permeable and hydrogel contact lenses. Adherence to rigid gas-permeable lenses was greater than the adherence to hydrogels. The lower incidence of microbial keratitis associated with rigid gas-permeable lenses, as compared with hydrogel lenses, may be attributed to the more rigorous cleaning and disinfection possible for rigid gas-permeable lenses and/or patient noncompliance with complicated disinfection systems used with hydrogel lenses.

Bacterial Adhesion↗
PubMed1991

Intraoperative gamma detection probe with presurgical antibody imaging in colon cancer.

In this study, presurgical gamma camera imaging and an intraoperative gamma detection probe were used in 12 consecutive patients 6 to 22 days after infusion with indium 111-labeled anticarcinoembryonic antigen monoclonal antibody (111In-MoAb). In three of 11 patients who underwent laparotomy, clinical management was affected by the probe findings: localization of occult retroperitoneal disease, identification of an occult cecal lesion, and localization of residual disease at a site of local recurrence. Of all intra-abdominal lesions seen using any method, the probe identified 18 (86%) of 21, compared with 14 (67%) of 21 with the 111In-MoAb scan, 10 (48%) of 21 by computed tomographic scan, and 16 (76%) of 21 after surgical exploration. Uptake of 111In-MoAb in the portal (n = 3) and mediastinal (n = 3) lymph nodes was not associated with histologic findings of malignant neoplasms. For all pathologically confirmed extrahepatic and nonportal sites of cancer, the probe localized nine of nine, compared with five of nine by 111In-MoAb scan, two of nine by computed tomographic scan, and six of nine by surgical exploration. Important clinical uses of the intraoperative probe included occult lesion identification, localization of areas with 111In uptake shown with MoAb scanning, and verification of complete resection of areas with 111In-MoAb uptake.

Abdominal Neoplasms↗
PubMed1991

Divergent efficacy of antibody to tumor necrosis factor-alpha in intravascular and peritonitis models of sepsis.

The role of tumor necrosis factor-alpha (TNF alpha) in the lethal consequences of intravascular lipopolysaccharide (LPS) or Escherichia coli sepsis was compared with that in bacterial peritonitis. Intravenous administration of E. coli LPS or E. coli (live or dead) resulted in large transient increases in serum TNF alpha levels, peaking at 90 min at 10,000-30,000 units/ml. In contrast, the serum TNF alpha response following the induction of bacterial peritonitis was substantially less, peaking at 200-500 units/ml. Sterile peritonitis (essentially nonlethal) and bacterial peritonitis (greater than 60% lethal) elevated TNF alpha levels to 1000-2000 units/lavage within the peritoneal cavity 2 h after challenge. Passive immunization with neutralizing goat anti-TNF alpha IgG improved survival from 8% to 75% in rats administered LPS intravenously but was completely ineffective in protecting rats from lethal E. coli peritonitis. Thus significant differences exist in the role TNF alpha plays in systemic intravascular models of sepsis and bacterial peritonitis.

Animals↗
PubMed1990

Microbial contamination of contact lens storage cases and solutions.

We compared microbial contamination of contact lens storage cases of asymptomatic contact lens wearers (Group 1; No. = 118; sampled once) and of contact lens wearers with manufacturer's lens-care instructions reinforced (Group 2; No. = 62; sampled three, six, 12, and 20 weeks after initial advisement). A significantly higher incidence of contamination of contact lens storage cases and solutions was observed among samples from Group 1 (132 of 247 samples) as compared to samples from Group 2 (30 of 500 samples; P = .000). Contact lens storage cases of individuals in Group 2 who used hydrogen peroxide systems (four of 78) showed a significantly lower incidence of contamination as compared to individuals who used other chemical disinfection (11 of 62 soft lens users; 10 of 59 rigid gas-permeable lens users; P = .041). Biofilms, adhered microorganisms embedded in a glycocalyx, in contact lens storage cases were not always inactivated by the addition of fresh solutions. Cleaning and periodic replacement of contact lens storage cases is recommended.

Bacteria↗
PubMed1990

Cefazolin levels after intravitreal injection. Effects of inflammation and surgery.

Cefazolin (2.25 mg) was injected into the vitreous cavity of phakic, aphakic, and aphakic/vitrectomized rabbits; inflamed eyes were compared to controls. Vitreous levels of cefazolin were determined at selected times from 2 to 48 hr, and the half-life was calculated. The effect of inflammation was to increase the half-life or to reduce the rate of elimination of cefazolin from the vitreous cavity. The drug was cleared substantially faster from aphakic/vitrectomized eyes than from phakic or aphakic eyes. Vitreous levels of cefazolin were above the MIC for most common gram-positive organisms causing endophthalmitis in all study groups at 24 hr, but in only the phakic inflamed eyes and in the aphakic eyes with intact vitreous at 48 hr.

Animals↗
PubMed1990

Vitreous cefazolin levels after intravenous injection. Effects of inflammation, repeated antibiotic doses, and surgery.

We devised a standardized rabbit model of intraocular inflammation using heat-killed Staphylococcus epidermidis as the inducing organism. We applied this model to study the effects of (1) inflammation, (2) repeated antibiotic doses, and (3) surgical status of the eye on cefazolin levels in the vitreous cavity after intravenous administration. Intravenous cefazolin sodium, 50 mg/kg, was administered every 8 hours for 48 hours. Eyes were harvested for assay of vitreous cavity antibiotic levels at various intervals from 1 to 49 hours. Drug levels were compared in inflamed and noninflamed eyes under both phakic and aphakic/vitrectomized conditions. At 1 hour, levels in phakic specimens were 3.0 mg/L in inflamed eyes vs undetectable in noninflamed eyes (P less than .01), but progressively increased to 10.6 mg/L at 49 hours (P less than .02) in inflamed eyes only. Levels in aphakic/vitrectomized eyes at 1 hour were 6.7 mg/L in inflamed eyes vs 4.2 mg/L in noninflamed eyes (P less than .1), but progressively increased to 24.9 mg/L at 49 hours (P less than .001) in inflamed eyes only. Levels at 49 hours in inflamed phakic and inflamed aphakic/vitrectomized eyes were well above the minimum inhibitory concentrations for organisms termed sensitive to cefazolin. We would conclude, therefore, that repeated doses of intravenous cefazolin may play an important adjunctive role in the treatment of endophthalmitis.

Analysis of Variance↗
PubMed1990

Comparative treatment of experimental Staphylococcus epidermidis endophthalmitis.

We created experimental Staphylococcus epidermidis endophthalmitis of moderate severity in the aphakic rabbit eye by injecting 100,000 organisms of a standardized laboratory strain (ATCC 155) into the mid-vitreous cavity. This model of endophthalmitis self-sterilizes in about 4 days, but inflammatory signs continue to increase 5 to 7 days after the initial bacterial inoculum. Control eyes were compared with eyes treated with five different strategies 24 hours after bacterial inoculation: intravitreal cefazolin sodium, intravitreal cefazolin plus intramuscular corticosteroid, vitrectomy plus intravitreal antibiotics, vitrectomy plus intravitreal antibiotics and intramuscular corticosteroids, and vitrectomy plus intravitreal antibiotics and corticosteroids. Quantitative grading of inflammation and media clarity were compared at the end of weeks 1, 2, and 3 after treatment. At week 1, eyes treated with vitrectomy had significantly lower inflammatory scores; those treated with corticosteroids had significantly lower scores than those without. The two effects were independent. The best results were observed with treatment consisting of vitrectomy, intraocular antibiotics, and corticosteroids. This strategy also produced significantly more eyes with clear media at the end of week 3 than treatment with intravitreal antibiotics alone.

Adrenal Cortex Hormones↗