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Biomedical subjects

E N Kaplan

Publications and source records attributed to E N Kaplan.

At least 19 recordsLinked to original sources
PubMed1996

Anterior hydrogel lens deposits: polished vs. unpolished surfaces.

Traditionally, lathe cut hydrogel lenses receive both back and front surface polishing to eliminate any surface irregularities that might serve as potential attachment sites for lens deposits or even microorganisms. However, with the advent of newer more technologically advanced lathing equipment, the need for lens polishing may require renewed justification. This study sought to compare, by scanning electron microscopy (SEM), anterior lens surface deposit formation on polished and unpolished 55% water hydrogel lenses. A total of 10 subjects wore in 1 eye (control) a lens with both front and back lens surfaces polished and on the other eye (test) a lens with only the back lens surface polished for a period of 2 weeks on a daily wear basis. Each lens was then scanned (using SEM), with 3 separate regions photographed at 30x using a 10 kV electron source. Using a Wilcoxon Signed-Ranks test on the differences between average deposit ratings for the polished and the unpolished lenses, by subject pair, we failed to reject the null hypothesis that the difference was zero.

Biofilms↗
PubMed1993

Parameter consistency in disposable lenses.

An evaluation of parameter consistency and edge defects as they might relate to premature lens fracture was undertaken for 2 disposable lens types, 50 Johnson & Johnson Acuvue lenses and 50 Wesley-Jessen FreshLook lenses. Diameter measurements varied from 13.97 to 14.48 mm (mean = 14.28 mm, SD = 0.138 mm) for Acuvue and 14.30 to 14.63 mm (mean = 14.41 mm, SD = 0.064 mm) for FreshLook. Based on previously reported information, these diameter variations for Acuvue may be sufficient to affect lens fitting characteristics. Calculated back surface sagittal depth varied from 3.27 to 3.38 mm (mean = 3.32, SD = 0.029 mm) for Acuvue and 3.68 to 3.87 mm (mean = 3.75 mm, SD = 0.039 mm) for FreshLook. Center thickness was generally consistent across the power range evaluated (-0.50 to -4.00 D) for the FreshLook lenses, and appeared to increase significantly for low minus powers for the Acuvue lenses. Twenty-one (44%) Acuvue lenses and 6 (12%) FreshLook lenses showed edge defects that might contribute to premature lens fracture.

Contact Lenses, Hydrophilic↗
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↗
PubMed1983

Silicone-induced human adjuvant disease?

Human adjuvant disease is an immunologically mediated disorder manifested by arthritis, arthralgias, skin lesions, malaise, pyrexia, and weight loss. Clinically, it often resembles rheumatoid arthritis and Reiter's syndrome. While scattered cases of adjuvant disease have been reported following injections with silicone fluid of unknown purity, paraffin, and petroleum jelly, no cases of adjuvant disease following silicone gel implant mammaplasty have been reported. We present such a case, discuss the pertinent biology of silicone, and review the literature describing adjuvant disease.

Adjuvants, Immunologic↗
PubMed1983

Clinical utilization of injectable collagen.

The applications for an injectable, highly purified form of calfhide collagen (Zyderm Collagen Implant) were first described by Knapp et al in 1977. Since that time, the material has undergone evaluation in a nationwide clinical trial in which 728 physicians participated under a cooperative protocol. In these trials--which culminated in marketing clearance by the Food and Drug Administration--over 5,000 patients were treated for a variety of soft-tissue depressions resulting from surgery, atrophy, acne, viral pox, and aging. We participated in the clinical trial and have used injectable collagen in our practices since 1977 when the material was undergoing evaluation in California. We have treated over 400 patients with injectable collagen for a variety of facial cutaneous defects. The material has proved to be an effective tool for correction of certain soft-tissue defects not previously amenable to correction, and a useful surgical adjunct. Simplicity and safety are its major advantages. The persistence of correction afforded by injectable collagen is variable, but the majority of our patients have maintained improvement twelve or more months since the end of treatment. Hence we believe that there is a definite role for injectable collagen but that its long-term persistence must still be confirmed. This paper represents our state-of-the-art assessment of injectable collagen after six years of personal experience.

Acne Vulgaris↗
PubMed1983

Fascicular tubulization: a cellular approach to peripheral nerve repair.

Present techniques of nerve repair by suture are based on an anatomical approach. The severed layers of connective tissue are reapproximated. Another approach to nerve repair is to separate the specific cellular components of the peripheral nerve that contribute to fibrous healing and nerve regeneration. The perineurium normally separates the extrafascicular epineurium of mesodermal origin from the intrafascicular endoneurium of ectodermal origin. A cellular approach to nerve repair would use a tube around the fascicle as an artificial perineurium to separate fibrous healing from axonal regeneration until the perineurium reestablishes its continuity. Fascicular tubulization with polyglycolic acid tubes was studied in 25 rats. The polyglycolic acid tube is resorbed after the perineurium has reestablished its continuity. The repairs by fascicular tubulization demonstrated improved organization of the repair site compared to suture repairs. The diameter histograms of the regenerated myelinated axons were similar in repairs by tube and suture techniques. The total regenerated cross-sectional area of the myelinated axons was similar in the repairs by fascicular tubulization to repairs by fascicular suture.

Animals↗
PubMed1981

Commissuroplasty and myoplasty for macrostomia.

The morphology of macrostomia and a method of myoplasty and commissuroplasty are described. The important operative considerations are accurate commissure positioning, muscle reconstruction, obliteration of the lateral subdermal groove, placement of a vermilion flap across the commissure, and Z-plasty of skin in the nasolabial crease.

Facial Muscles↗
PubMed1981

Atypical mycobacterial cervical lymphadenitis--treatment with surgery and antibiotics.

Five patients, ages 2 to 5 years, were successfully treated for cervical lymphadenitis caused by the avium intercellulari complex of atypical bacteria. Preoperative treatment with standard antituberculosis therapy had been unsuccessful. Extensive surgery requiring a conservative radical neck dissection was sometimes required. Three patients had such extensive and progressive disease that immediate excision was impossible. These patients received a course of Amikacin with considerable improvement, permitting adequate excision and reconstruction. A fourth patient who received Amikacin did not respond, although sufficient excision was possible. This preliminary data indicates that a combined treatment of Amikacin and surgery in extensive cases may be useful in the treatment of cervical lymphadenitis due to atypical mycobacteria.

Amikacin↗
PubMed1980

Use of the medial upper arm skin as an arterialised flap.

The skin on the underside of the upper arm is supplied in part by the superior ulnar collateral artery, a direct cutaneous artery arising from the brachial artery four to six cm distal to the pectoralis major insertion. Two-thirds to three-quarters of the length of the medial arm skin can be reliably transferred as an arterialized undelayed pedicle flap. This skin provides excellent coverage for the opposite hand from a relatively inconspicuous donor site. Transfer of this flap is safe and patient discomfort is minimal. It is recommended for elective reconstruction and emergency procedures.

Adult↗
PubMed1980

An arterial medial arm flap--vascular anatomy and clinical applications.

We describe the vascular distribution to the skin of the arm as determined by cadaver dye injections and anatomical dissection. The superior ulnar collateral cutaneous artery provides a direct cutaneous branch that supplies the proximal two-thirds of the medial arm. An arterialized flap from the medial arm is very thin, elastic, and hairless--therefore excellent for hand resurfacing and facial reconstruction. Five examples of the use of arm skin from 21 patients using local and distant flaps are shown. The indications, methods, and anatomical bases for flap delay are detailed. The Doppler flow meter is used to determine artery position.

Adult↗
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↗