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Biomedical subjects

S A Fowler

Publications and source records attributed to S A Fowler.

33 records · Page 2Linked to original sources
PubMed1981

The effect of cleaning soft contact lenses. A scanning electron microscopic study.

Scanning electron microscopy was used to investigate the effectiveness of surfactant and enzyme cleaners in removing coatings from soft contact lenses. We examined ten continuously worn lenses and 15 lenses worn and cleaned regularly for at six months. About 30% of the surface of continuously worn lenses cleaned with surfactant or enzyme was uncoated; smooth, matted coating covered the remainder. Continuously worn lenses cleaned with the combination surfactant and enzyme cleaner had similar deposits covering 50% of the surface. Lenses worn and cleaned regularly had more deposits after cleaning with surfactant or enzyme cleaner than after cleaning with combination cleaner. Approximately 25% of the surface of lenses cleaned with the combination was coated with deposits. The deposits on both types of lenses were about 30% less thick after use of the combination cleaner than with either single cleaner. The coating on worn contact lenses is not completely removed by any method we tested.

Contact Lenses, Hydrophilic↗
PubMed1981

"Do I have to be good all day? The timing of delayed reinforcement as a factor in generalization.

Delayed reinforcement, sometimes delivered just after the setting in which the critical behavior had occurred (Early), and sometimes delivered only after several further settings had been encountered (Late), was used to improve a variety of behaviors in seven preschool children, and to control their generalization. Performance of those behaviors was measured in two classroom settings: the Contingent setting, within which performance of the specified behavior determined the latter (Early or Late) reinforcement, and the Generalization setting, in which there were no experimental contingencies, immediate or delayed, for the performance of the same behavior. Performances by all children in the Contingent setting were controlled by delayed reinforcement, whether Early or late. All children showed consistent generalization from the Contingent setting to the Generalization setting during the Late condition, when reinforcement was delivered at the end of the school day. Generalization did not occur during the Early condition, when reinforcement was provided immediately after the Contingent setting (prior to the Generalization setting), unless that condition had been preceded by a Late condition (as it was for S6 and S7). The results suggest that the Late timing of delayed reinforcement was an effective and efficient generalization-promotion technique for performances that did not generalize spontaneously.

Behavior Therapy↗
PubMed1980

Evolution of soft contact lens coatings.

To investigate further the reported possibility that surface deposits on soft contact lenses contribute to giant papillary conjunctivitis, we performed scanning electron microscopy on 22 lenses worn for varying durations by a group including persons who had never worn contact lenses and asymptomatic persons who had, and on five never-worn lenses. Thirty minutes' wear resulted in covering of about 50% of the anterior surface with scattered cell-membrane-like and mucus-like material, with mucus-like material on top of cells in places. Eight hours' wear produced about 90% covering with more complex coatings. Routinely worn and cleaned lenses had still more complex coatings on more than 90% of the surface. Deposits were found on routinely worn lenses even after professional cleaning. We conclude that all worn soft contact lenses have coatings that become more complex with time and may never be removed completely.

Cell Membrane↗
PubMed1980

The surface of the continuously worn contact lens.

The anterior surfaces of continuously worn therapeutic contact lenses and routinely cleaned cosmetic lenses were compared by scanning electron microscopy. The continuously worn lenses were uniformly and completely coated with material thicker and smoother that that on the incompletely coated cosmetic lenses. It is concluded that continuously worn lenses build up coatings steadily, whereas routinely cleaned lenses have at least part of the coating removed with each cleaning.

Conjunctivitis↗
PubMed1979

Attachment of bacteria to soft contact lenses.

A total of 25 soft contact lenses from 17 asymptomatic contact lens wearers and eight patients with contact lens-associated giant papillary conjunctivitis were examined by scanning electron microscopy. Structures that resembled bacteria were present on the anterior surface of seven lenses. All lenses showed a coating of granular mucus-like deposits. Some bacteria were seen scattered randomly over the surface, with no apparent attachment to the lens, whereas others were attached to the coated surface by thin, flagella-like foot processes, the distal ends of which were unattached. These attached bacteria were cylindrical in shape. Several bacteria showed a constriction centrally. Some bacteria were covered by the surface coating, while others, which were round to ovoid in shape, appeared partially embedded in the coating itself. Aggregations of bacteria were seen around clumps of mucus-like debris.

Bacteria↗
PubMed1979

Soft contact lenses from patients with giant papillary conjunctivitis.

We used scanning electron microscopy to study the surfaces of five coated soft contact lenses from subjects with giant papillary conjunctivitis. Findings were compared to the surfaces of five coated lenses from normal, asymptomatic wearers and five new, nerver-worn lenses. Lenses were from various manufacturers. All worn contact lenses differed strikingly from new, never-worn lenses. The anterior surface of worn lenses was covered with apparently adherent deposits. In only a few areas was the surface similar to new, never-worn lenses. Thick coatings on lenses from patients with giant papillary conjunctivitis and asymptomatic wearers were similar. High magnification of the coatings revealed a trabeculated morphology. Also seen was debris that resembled mucus-like material in both strand and particulate forms. On some lenses bacterial-shaped structures were scattered randomly over the surface. Smooth structures resembling cells were also seen. The posterior lens surface of all worn lenses was smoother than the anterior lens surface. The findings support our idea that the capacity to develop giant papillary conjunctivitis is influenced by individual differences more than by differences in lens deposits.

Adult↗
PubMed1978

Calcium and 25-hydroxyvitamin D3 binding proteins in human placenta.

The placental translocation of calcium is a well-known process, but the underlying mechanisms remain unknown. Placental cytoplasmic proteins capable of binding calcium and the active metabolites of vitamin D3 were sought in these studies. Cytosol from full-term human placenta was prepared by ultracentrifugation of homogenates and tested for binding. Partial purification by column chromatography revealed the presence of two discrete proteins which bound specifically 45Ca and 3H-25-hydroxyvitamin D3 and having approximate molecular weights of 12,000 and 67,000, respectively. These placental proteins may be intermediaries in the process of placental calcium translocation.

Calcium↗
PubMed1978

Training preschool children to recruit natural communities of reinforcement.

Four normal and four deviant children aged four-to-six years were taught to judge the quality of their academic work in a preschool classroom, and to prompt or cue their teachers to comment about the quality of that work. When these skills did not generalize spontaneously to other teachers in concurrent natural situations, generalized responding was taught by the experimenter, in multiple-baseline design across subjects. This generalization programming enabled the children to contact a sometimes dormant, but readily available natural community of teacher praise and reinforcement, i.e., to recruit an increase in cued praise and schedules of praise for their good work. These behaviors may be important to young children who find themselves bereft of attention in classrooms.

Child↗
PubMed1976

Color-matching technique to train children in the correct use of stairs.

Color cues were used to train four severely retarded children and two learning disabled children to move in a left foot-right foot alteration pattern when using stairs. The occurrence of left-right alterations and marking time behavior was recorded throughout baseline and training conditions. The color-cue procedure effectively produced a consistent pattern of alteration of four of the children and eliminated marking time in three of the children. Physical prompts were used to train alteration in two children for whom color-cue training was not sufficient. At the termination of training, observations of the children's performances in new settings and to new adults were conducted. Results indicated that the children continued to alternate correctly. In addition, follow-up investigations conducted between two weeks to 16 months after training indicated that the children were maintaining the stair alteration pattern. Future research should determine whether a visual-cue procedure could be used in training other forms of locomotion or motor behavior.

Adolescent↗
PubMedDate not supplied

Perspectives on the transition from preschool to kindergarten for children with disabilities and their families.

This article addresses the transition of young children from preschool programs that provide special education services to kindergarten or alternative elementary school placements. The roles of the child, family, and service providers in transition preparation, planning, implementation, and evaluation are described. Successful transitions include assessments of children's skills in meeting the demands of kindergarten programs, teaching these skills to children, and actively encouraging parent participation in plans and programs. Barriers to successful transitions include lack of time and funding to coordinate both parent activities and between-school arrangements. A critical area for future research is the long-term evaluation of the procedures described as "best practice," as well as the definition of what constitutes a successful transition.

Child, Preschool↗
PubMedDate not supplied

Scanning electron microscopy of deposits remaining in soft contact lens polishing marks after cleaning.

Deposits are a complication of contact lens wear that have been associated with ocular diseases, including keratitis and giant papillary conjunctivitis. The purpose of this morphologic study was to describe the deposits on soft contact lenses fabricated by different surface manufacturing methods and to evaluate the ease of removal of deposits by surfactant cleaning. We studied the anterior surfaces of 30 soft contact lenses (10 lathe cut [polished]; 10 spin cast [unpolished], and 10 cast molded [unpolished]) of the same polymer and water content. All lenses were worn for 8 hours by two asymptomatic persons who did not routinely wear contact lenses. Lenses from one eye were immersed in glutaraldehyde, while lenses from the other eye were cleaned before immersion in glutaraldehyde. All lenses were then dehydrated in graded alcohols, critical-point-dried, and observed by scanning electron microscopy. The amount of deposit on the lens surface was judged by an individual who did not know the identity of the lens. All lenses showed similar types of deposits. At the end of 8 hours wear, all types of lens surfaces were covered with deposits. Cleaning removed some but not all deposits. The lens surfaces manufactured in such a way as to leave polishing or lathe marks showed deposits "heaped-up" on the marks before cleaning and remaining in the mark after cleaning. Polishing marks from lens fabrication may represent an increased risk for conjunctival insult from deposits remaining in the marks after cleaning.

Contact Lenses, Hydrophilic↗