PubMed Health⌕ Search

Biomedical subjects

E N Kaplan

Publications and source records attributed to E N Kaplan.

16 recordsLinked to original sources
PubMed1992

Quantitative analysis of visual acuity through amber discolored lenses.

Discoloration of hydrogel contact lenses is frequently encountered in clinical practice and often precipitates lens replacement. This investigation sought to determine if lens discoloration was associated with a compromise in low or high contrast, high illumination visual acuity. This association would lead to a more scientific rationale for lens replacement. Amber lens discoloration was achieved using human-worn 55% water hydrophilic contact lenses (Methafilcon-A) heated in a 1% potassium sorbate, low pH saline solution. A spectrum of 6 discolored lenses was obtained with a peak absorbance at 320 nm. Fifteen subjects, between the ages of 22 and 38 years, were tested wearing each of the discolored lenses. None of the differences in high or low contrast acuity between our discolored and nondiscolored lenses were found to be statistically significant using a paired t-test at the 99% significance level.

Adult↗
PubMed1992

Residual hydrogen peroxide as a function of platinum disc age.

Recently there has been considerable attention given to the possible deleterious effects of residual hydrogen peroxide on both the cornea and the crystalline lens of the eye. We measured residual hydrogen peroxide levels of the AOSept disinfection system at regular intervals over a 4 month period. By 1 month the residual hydrogen peroxide level was 21 ppm +/- 9.4 (mean +/- standard deviation); at the end of 2 months it was 36 ppm +/- 17.6. At 3 months, when disc replacement is recommended, the residual hydrogen peroxide level was 43 ppm +/- 4.7 (range: 17-98 ppm). At 4 months the residual hydrogen peroxide level rose to a mean of 48 ppm +/- 18.2. The increase in measured residual hydrogen peroxide between month 1 and each successive month was found to be statistically significant. However, these levels failed to induce an increase in symptomatology or slit lamp findings. As determined by scanning electron microscopy there was an erosion of the platinum coating with time that appeared to coincide with the measured residual peroxide level. Cultures of randomly selected platinum discs at the end of 4 months failed to reveal more than isolated positive findings of Staphylococcus epidermidis. While an increase in residual peroxide with time may lead to greater disinfecting capabilities of this system, the possibility of corneal damage as a direct result of high peroxide levels is of concern.

Adult↗
PubMed1987

Efficient RecABC-dependent, homologous recombination between coliphage lambda and plasmids requires a phage ninR region gene.

A phage lambda gene that gives a 100-fold increase in recombinant frequencies for RecABC pathway-mediated, phage-plasmid homologous recombination (Shen and Huang 1986) maps to ninG (orf 204) of lambda. We call this gene rap, for recombination adept with plasmid. A similar determinant exists in Charon 4A and maps in phi 80-derived sequences, between nin5 and the Rz homology with lambda. The absence of the Rap+ phenotype from certain lambda vectors explains the inefficiency of screening the resulting phage libraries using phage-plasmid homologous recombination. The mapping of rap permits the construction of lambda vectors more suitable for this screening technique.

Bacteriophage lambda↗
PubMed1978

Growth of the unilateral cleft lip.

Growth discrepancies have frequently been noted following surgery for the repair of clefts of the lip. A long lip is often noted months or years after LeMesurier, Tennison, or Asensio repair, whereas a short lip is noted after the Millard repair. We evaluated the problem by measuring 112 unrepaired unilateral completed cleft lips in a homogeneous population. Patients of all ages from newborn through adults were included. The study showed that a cleft lip has ten to twenty per cent greater growth in the transverse direction parallel with the orbicularis muscle than in the vertical direction perpendicular to the muscle. Thus, procedures such as those of LeMesurier and Asensio that transpose tissue from transverse to vertical will lead to excessive vertical growth. Lip growth is slightly decreased along the cleft margins but does not account for the short lip seen after the original Millard repair. Lip shortness occurs soon after repair because of scar contracture but tends to resolve with the passage of time.

Adolescent↗
PubMed1977

Pathologic scar formation. Morphologic and biochemical correlates.

Morphologic and biochemical analyses were performed to compare normal skin and mature scars to hypertrophic scar and keloid. Correlation of morphologic findings with biochemical profiles of the skin and scar samples proved feasible and enlightening. Scanning electron microscopy (SEM) was used to characterize the architectural arrangement of collagen fibers in skin and scars. Cultured fibroblasts from each specimen were also examined with the SEM. A biochemical profile of each tissue specimen was constructed, characterizing the collagen component of the specimen by sequential molecular sieve and ion exchange chromatography to determine a) the degree of intermolecular crosslinking, b) amino acid analysis, and c) levels of lysyl oxidase activity. Results indicate that collagen fibers and fiber bundles display a decreasing level of organization as the clinical degree of scar abnormality increases, and this structural gradient correlates with the gradient of intermolecular crosslinking in the same tissue--normal skin and mature scar being highly crosslinked, hypertrophic and keloid successively less so. Surprisingly, the level of the crosslinking enzyme lysyl oxidase is normal or elevated in hypertrophic scar and keloid despite the relative lack of crosslinking. Amino acid content was uniform for all specimens. Scanning electron microscopy examination of cultured fibroblasts from the tissue specimens demonstrated three phenotypically distinctive fibroblasts whose numerical and volumetric proportions correlated with the tissue of origin.

Amino Acids↗
PubMed1977

Microvascular anastomosis using a blood product sealant-adhesive.

In this experimental model, we have shown that a four suture repair with a biologic sealant adhesive significantly reduces hemorrhage and reduces operative time, while allowing a flap survival comparable to that obtained with standard techniques in rats undergoing a microvascular anastomosis. In heparinized rats undergoing the same procedure, the sealant adhesive significantly decreases hemorrhage and increases flap survival. Of significance is the fact that the platelet-fibrinogen-thrombin adhesive is biodegradable and does not induce a tissue reaction. We believe that this physiologic adhesive may become a useful adjunct in digital reimplantation. It appears to reduce operative time and heparin-induced bleeding.

Animals↗
PubMed1977

The surgical treatment of necrobiosis lipoidica diabeticorum.

We review the literature on the surgical treatment of necrobiosis lipoidica diabeticorum, and we describe 7 cases treated at Stanford University Medical Center. Experiences with them prompt us to recommend surgical excision of the lesions down to the deep fascia, ligation of the associated perforating blood vessels, and the use of split-skin grafts to cover the defects. There were no recurrences when we did all these things.

Adolescent↗
PubMed1977

Injectable collagen for soft tissue augmentation.

Collagen from allogenic and xenogeneic sources has been made soluble by controlled proteolytic digestion. The monomeric, telopeptide-poor collagen so prepared forms a cohesive mass when warmed to body temperature (upon injection), creating a structural basis for new soft connective tissue. We have treated 28 patients with human and/or bovine collagen injections for the correction of soft tissue contour defects, and we have followed them for 3 to 18 months. In most instances, there has been lasting and substantial correction of the defects treated. The complications have been few and transient.

Acne Keloid↗
PubMed1976

Cephalometric study of facial growth in children after combined pushback and pharyngeal flap operations.

Linear and angular cephalometric measurements of children who had had combined palatal pushbacks and superiorly-based pharyngeal flaps do not show later growth retardation of the face. There was an inherent tendency for children with overt clefts of the secondary palate, classic submucous clefts, or occult submucous clefts to demonstrate pre-operatively a narrow SNA and SNB--but the difference between these angles (ANB) was normal.

Cephalometry↗
PubMed1975

The occult submucous cleft palate.

We have studied 41 patients with classic submucous cleft and 32 cases with occult submucous cleft. Both groups have the same anatomic abnormality that leads to velar dysfunction-the insertion of the palate muscles onto the hard palate rather than onto the midline soft palate raphe. However, the occult submucous cleft palate does not have the classic triad of bifid uvula, hard palate bony notch, and furrow in the midline of the soft palate. Characteristic facial features, cephalmetric x-rays, and cine voice studies can help make a presumptive diagnosis of occult submucous cleft palate. Surgical management includes a diagnostic palate exploration to identify muscle configuration followed by levator muscle sling reconstruction, palate pushback, and pharyngeal flap. Excellent speech results are obtained except with patients having palate paresis.

Abnormalities, Multiple↗