Biomedical subjects

J S Yager

Publications and source records attributed to J S Yager.

6 recordsLinked to original sources

PubMed1998

Polyester as a bioimplantable material.

In response to the recent controversy over silicone gel implants, alternative substances are being sought to offer new options in bioimplantable materials. Polyester is a Food and Drug Administration-approved prosthetic material utilized in vascular grafts for decades without significant problems in body tolerance. Working with textile scientists, polyester (both in its woven and fibrous forms) was engineered to influence differential fibrous ingrowth. Implants of medical-grade polyester were constructed in a 3-cm2 diskette configuration. Four combinations of material with varying layers of weave and fiber were created to influence tissue ingrowth differentially. Four implants were placed in separate dorsal pockets beneath the panniculus carnosus of each of 12 adult female New Zealand White rabbits. Care was taken to sort the implant types equally among the four quadrants such that a similar distribution of implants existed between animals. Implants with intact capsules were harvested at 1, 3, and 6 months, and were analyzed for histology, capsular thickness, and tissue ingrowth. A phantom mammogram was taken through the implant material that did not obscure interpretation. The materials were further tested to determine fiber fill-to-wet implant weight ratios to determine postimplantation weight predictably. Tensile strength was also determined.

Animals↗

PubMed1998

Inhibition of fibroblast-populated collagen lattice contraction by an albumin-bound lipid fraction in human amniotic fluid.

Human amniotic fluid inhibits the contraction of fibroblast-populated collagen lattices. Amniotic fluid of 21 weeks' gestation was previously reported to have peak inhibiting activity. An attempt to isolate the inhibitory factor(s) from human amniotic fluid employing a molecular sieving column demonstrated an inhibitory factor near 70,000 molecular weight (repeated three times with triplicate samples). Since albumin has a molecular weight of 68,000 and is in high concentration in amniotic fluid, the removal of albumin by an Affi-Gel Blue (an albumin binding affinity column) was the first step in the purification scheme. The bound human amniotic fluid albumin fraction was eluted from the Affi-Gel Blue column, and the unexpected finding was that this fraction inhibited fibroblast-populated collagen lattice contraction (three repetitions in duplicate). We previously showed that prostaglandins and saturated and unsaturated fatty acids affect fibroblast-populated collagen lattice contraction, and albumin is a carrier for lipids. The eluted albumin fraction was separated into its protein and lipid components. The lipid-free albumin fraction had no fibroblast-populated collagen lattice contraction inhibiting activity (run four times in duplicate). The isolated lipid fraction inhibited fibroblast-populated collagen lattice contraction in a dose-responsive manner (repeated twice in triplicate). It was demonstrated that lipid bound to albumin isolated from human amniotic fluid inhibited fibroblast-populated collagen lattice contraction.

Albumins↗

PubMed1997

A method of breast reconstruction with a deepithelialized TRAM flap via the abdominal approach for failed implant salvage in postmastectomy patients.

Postmastectomy reconstruction of breasts is one of the most commonly performed procedures of the plastic surgeon today. Tissue expansion with subsequent implant placement, transverse rectus abdominis musculocutaneous (TRAM) flaps, latissimus dorsi flaps, gluteal flaps, Ruben's fat pad flaps, and free flaps from other areas have all been utilized with consistently good aesthetic results. One special class of patient is the woman who has undergone breast reconstruction with tissue expansion, with or without subsequent implant placement, who than receives external beam radiation therapy. Capsular contraction frequently complicates this therapy. In the past, women have undergone capsulotomy or capsulectomy with replacement of the implant. Recently, women are more reluctant to have foreign tissue in their bodies and are opting for autologous tissue reconstructions. TRAM reconstruction following removal of implants has been previously reported. A new approach to the placement of the TRAM flap after implant reconstruction via the abdominal approach, with avoidance of any incision on the breast itself, is presented. This is especially important in a patient who has evidence of radiation damage to the skin, placing any incision through the treated tissue at risk.

Breast Implants↗

PubMed1993

The inhibition of fibroblast-populated collagen lattice contraction by human amniotic fluid: a chronologic examination.

The effect of human amniotic fluid on fetal wound healing remains to be fully elucidated and may lead to the isolation of factors that could modulate adult wound healing. This study uses an in vitro model of wound contraction, the fibroblast-populated collagen lattice, to examine the effects of chronologically sampled human amniotic fluid on contraction of lattices composed of either human adult or fetal fibroblasts. This chronology has not been reported previously. Human amniotic fluid was obtained in a sterile fashion via amniocentesis from 120 different women at different time points in gestation, ranging from 13 to 24 weeks. At each time point of gestation, three to five samples were individually examined in duplicate sets. Only fluid from pregnancies deemed normal by amniocentesis was included. Contaminated specimens were discarded. Using Bell's protocol, lattices were constructed of acid-soluble rat tail collagen, growth medium, and either human adult fibroblasts or human fetal fibroblasts. Lattices contained 20% v/v human amniotic fluid. In the control lattices, phosphate-buffered saline replaced amniotic fluid in equal volumes. Area was measured at 24-hour intervals, and all tests were run in duplicate for each specimen. The mean area at each interval was computed for each gestational week examined. Data were analyzed for significance with ANOVA and Dunnett's t test against control.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗

PubMed1992

Evaluation of sulbactam plus ampicillin for treatment of experimentally induced Klebsiella pneumoniae lung infection in foals.

Efficacy of sulbactam, a beta-lactamase inhibitor, in combination with ampicillin, was evaluated for treatment of experimentally induced pneumonia caused by beta-lactam-resistant Klebsiella pneumoniae. Infection was experimentally induced in 18 healthy weanling foals that were randomly allocated to 3 treatment groups: sulbactam plus ampicillin (S/A, 3.3 and 6.6 mg/kg of body weight, respectively), ampicillin (6.6 mg/kg), or vehicle only. Foals were treated daily for 7 days; the observer was unaware of treatment status. Compared with ampicillin and vehicle, treatment with S/A resulted in a statistically significant (P less than 0.05) decrease in severity of pneumonia, with regard to bronchoalveolar lavage cytologic findings (decreased total cell and neutrophil numbers, and increased lymphocyte numbers) and extent of macroscopic lesions in lung tissue of the noninoculated regions. Marked trends toward improvement of S/A-treated foals were observed for quantitative results of bacteriologic culture of bronchoalveolar lavage fluid samples (P less than 0.07), macroscopic pathologic features of the whole lung (P less than 0.1), and histopathologic variables (P less than 0.07), compared with ampicillin- and vehicle-treated foals. Treatment effects were not observed for radiographic, hematologic, and blood gas abnormalities that resulted from infection. In conclusion, the combination of sulbactam plus ampicillin was found to have synergistic effects in vivo, to reduce the extent and severity of experimentally induced gram-negative lung infection in foals.

Ampicillin↗

PubMed1991

Skin closure with dye-enhanced laser welding and fibrinogen.

The topical application of wavelength-specific dye and fibrinogen has been used to enhance laser closure of vascular anastomoses. We compared the closure of skin incisions by two different dye-enhanced, fibrinogen-based laser welding systems [argon laser (power density 4.78 W/cm2) with fluorescein isothiocyanate dye (n = 32) and diode laser (power density 9.55 W/cm2) with indocyanine green dye (n = 32)] with closure by interrupted 5-0 nylon suture (n = 64) and examined tensile strength, hydroxyproline production, histology, and cosmesis. Two 3-cm full-thickness incisions were made on the shaved backs of 64 rats. One incision was closed with suture, whereas the other, after treatment with the appropriate dye, was welded with either argon- or diode-lasered fibrinogen. At postoperative days 5, 10, 15, and 28, the closure sites were harvested and sectioned for analysis. Initially, wounds closed with argon-lasered fibrinogen showed less inflammatory response, greater collagen production (34.61 +/- 0.74 mg/gm), and greater mean peak stress at rupture (64.85 lbs/in2) than those closed with suture (16.42 +/- 3.20 mg/gm, 26.68 lbs/in2) (p less than 0.05). By 15 days, both argon and diode laser closures are superior in strength and collagen production to suture closure (p less than 0.05). At 28 days, diode laser closures (1315.60 lbs/in2) are stronger than suture closures (998.09 lbs/in2), whereas both are stronger than argon laser closures (813.16 lbs/in2) (p less than 0.05). Cosmetically, argon-welded wounds consistently appeared finer and lacked cross-hatched suture scars.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗