PubMed Health⌕ Search

Biomedical subjects

L C Argenta

Publications and source records attributed to L C Argenta.

At least 19 recordsLinked to original sources
PubMed1992

Arachidonic acid metabolites: effects on inflammation of fetal rabbit excisional wounds.

Uncovered fetal rabbit excisional wounds do not exhibit any classic signs of healing; wounds covered with an impermeable cover do contract, reepithelialize, and exhibit inflammation. Prostaglandin E2 (PGE2) is elevated in amniotic fluid, acting as an immunosuppressant at the maternal-fetal interface. Full-thickness excisional wounds were made on 25-day gestational age rabbit fetuses. Half the wounds were covered with an impermeable cover. Tissue from covered, uncovered, and nonwounded fetuses was examined 72 h after wounding for arachidonic acid metabolites. Uncovered wounds had significantly (P less than or equal to 0.05) elevated levels of PGE2, PGF2 alpha, and 12-HETE versus covered wounds and control tissue. Covered wounds had significantly elevated levels of 15-HETE compared to uncovered and control tissue. The elevated PGE2 in uncovered wounds may act as a fetal immunosuppressant; covered wounds (lower PGE2) developed cellular inflammation. Further investigations of these interactions may permit modulation of adult inflammation.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

Surface area and tissue volume increases with differential expansion.

Increasing sophistication in generating soft tissue by tissue expansion has resulted in the evolution of differential expanders. These prostheses attempt to asymmetrically generate tissue for specific reconstruction, most commonly the breast. Using the pig model, differential expanders were placed in the rib area. A square grid was marked over the area, and the expander inflated. For each grid subunit, the surface area was calculated, the thickness measured, and the volume calculated. Subunits in the area of preferential expansion exhibited the greatest increase in surface area, however, these same subunits exhibited pronounced thinning of the tissue. The corresponding volume of these subunits was greater than that of nonexpanded subunits, but the increase was less than when comparing subunit surface area. All expanders were displaced superiorly during the course of inflation. These findings are of clinical significance in that the mastectomy scar and nipple reconstruction both are situated in the area of minimal thickness. Displacement of differential expanders must be anticipated so that the resultant inframammary fold will ultimately be symmetrical with the opposite side.

Animals↗
PubMed1992

Dentocutaneous fistula.

Chronic dental infection is the most common cause of draining sinus tracts of the face and neck. These lesions can be a diagnostic challenge to the clinician who is not familiar with dentocutaneous fistula. Diagnostic errors can result in multiple excisions, biopsies, and ineffective long-term antibiotic therapy. Patients may require excision of the fistula once the dental abscess has been successfully treated by root-canal therapy or extraction. Nine patients are reported.

Adolescent↗
PubMed1991

Cellular inflammation of fetal excisional wounds: effects of amniotic fluid exclusion.

The development of an cellular inflammatory response secondary to mechanical wounding has not been observed previously in the fetus. The effect of amniotic fluid exclusion on the inflammatory response in fetal rabbits subjected to full-thickness dorsal excisional wounds on day 25 of gestation (term = 31-32) was examined. The fetuses were either returned immediately to the uterus; a silicone cover was sutured over the wound; or a silicone cover with a centrally located hole was sutured over the wound. Seventy-two hours after wounding, uncovered wounds (19 live fetuses) exhibited only occasional inflammatory cells. Covered wounds (14 live fetuses) showed a pronounced cellular inflammatory response. Partially covered wounds (six live fetuses) showed a peripheral, intermediate response. The findings suggest that amniotic fluid contains factors inhibitory to inflammation, which the cover effectively excludes.

Amniotic Fluid↗
PubMed1991

The safety of intravenous fluorescein administration.

Intravenous fluorescein is frequently used to assess tissue perfusion and predict flap viability, although its safety has recently been questioned due to cardiovascular side effects. Vital signs of 50 patients who received fluorescein were monitored by anesthesiologist to assess flap viability. Blood pressure readings were recorded at 5-minute intervals for at least 1 hour before and after fluorescein administration. Repeated measure analysis of variance was performed to determine any significant sustained (greater than or equal to 30 minutes) or transient (less than or equal to 15 minutes) differences in pressure changes after fluorescein administration. No significant (p less than or equal to 0.1) differences in pressure were noted for any identifiable group of patients. Minor reactions included transient nausea with no vomiting (5), sustained blood pressure increases of greater than 10% preadministration values (9), transient pressure drops of greater than 10% (10), and sustained pressure drops of greater than 10% (4). These 4 patients responded to increased fluid therapy without need for pressor agents.

Adult↗
PubMed1991

The effects of partial and total amniotic fluid exclusion on excisional fetal rabbit wounds.

Previous studies have consistently demonstrated that fetal rabbit excisional wounds exposed to amniotic fluid do not heal in utero. This study examines fetal wounds covered to exclude amniotic fluid. Full-thickness excisional wounds were created on fetal rabbits on day 25 of gestation. The following three treatment groups were examined: uncovered (n = 19 live); covered, a silicone cover was sutured over the wound (n = 14 live); and donut, a silicone cover containing a 2-mm central hole was sutured over the wound (n = 6 live). Fetuses were returned to the uterus and harvested by cesarean section 72 hr postoperatively. Fetal (covered) wounds excluded from amniotic fluid contracted and reepithelialized up to confluence. Sixteen of 19 uncovered wounds expanded, 3 were unchanged; minimal reepithelialization was present in all wounds. Partially (donut) covered wounds exhibited an intermediate response. This study shows that excisional wounds in the rabbit fetus respond to injury by contracting and reepithelializing when excluded from amniotic fluid.

Amniotic Fluid↗
PubMed1991

In vitro adhesion of endogenous skin microorganisms to breast prostheses.

Bacterial proliferation on polymeric biomaterials varies with the material and microorganism. Subclinical infection is implicated frequently as the initiative factor in capsular contracture around breast prostheses. The ability of endogenous skin microorganisms to produce an exopolysaccharide "slime" is emerging as an important factor in biomaterial colonization. This study was designed to demonstrate the ability of microorganisms of varying slime productivity to colonize, in vitro, different kinds of breast prostheses. Six-millimeter disks from seven kinds of silicone prostheses and polyurethane foam were exposed to three radioactivity labeled strains of bacteria, one slime producer, and two non-slime producers, for 1 hour. Data were expressed as colony-forming units bound per disk. There was no significant difference in adherence between the bacterial strains used, suggesting that initial adherence was nonspecific. The adherence did not appear to be related to surface type, whether smooth or textured, nor to the polymeric composition of the implant material, whether silicone or polyurethane, nor to the presence or absence of slime. Also, adherence was consistent with expected nonspecific bacterial adherence to biomaterials.

Bacterial Adhesion↗
PubMed1991

Monodelphis domesticus: a model for early developmental wound healing.

Fetuses heal significantly differently than adults; amniotic fluid and the fetal environment have profound effects on the fetus' response to excisional wounding. The Brazilian gray short-tailed opossum (Monodelphis domesticus) is presented as a new model for early developmental wound healing. This is a small, docile, pouchless marsupial whose young, at birth, are equivalent to an 8-week gestational age human, which allows investigations of early developmental wound healing exclusive of the amniotic environment. Incisional and excisional wounds were made on the dorsum of pups 1 or 15 days after birth. The pups were killed 1, 3, or 6 days after wounding and were fixed for histology. All incisional wounds were bridged by keratinocytes within 24 hours. Day 1 excisional wounds healed 6 days after wounding with a hypertrophic layer of keratinocytes and no inflammation. Day 15 excisional wounds exhibited inflammation, focal necrosis, and healing by epithelial migration 6 days after wounding. This model allows for investigations into early developmental wound healing and exhibits responses dependent on age similar to prepartum and postpartum young of higher mammals.

Animals↗
PubMed1991

Analysis of silicon in human breast and capsular tissue surrounding prostheses and expanders.

Diffusion of polydimethylsiloxane from silicone breast prostheses and soft-tissue expanders has been associated with capsular contraction. We used electron dispersive x-ray analysis and scanning electron microscopy to assess the presence of silicon in capsular tissue surrounding three categories of breast prostheses and expanders. Breast and subcutaneous tissues external to the capsules were used as control specimens. Semiquantitative results allowed capsules to be ranked according to implant type. Silicon was localized within the inner 2.0 mm of capsular tissue. The analyses of tissues from 2 patients exhibiting unilateral, Baker grade IV contraction after bilateral placement of prostheses showed less silicon present in the severely contracted capsule than in the less-contracted capsule. Results from this study diminish the importance of silicon as the initiator of capsular contraction.

Breast Diseases↗
PubMed1991

Scalp necrosis in a neonate treated with cultured autologous keratinocytes.

A neonate compromised by a stressful labor, low birth weight, anemia, seizures, and enterocolitis developed necrosis of a caput succedaneum of the calvaria. Coverage with cultured autologous keratinocytes was successful and represents a treatment modality with minimal morbidity compared with conventional split-thickness skin grafts.

Birth Injuries↗
PubMed1991

Management of the chest-wall deformity in male patients with Poland's syndrome.

The chest-wall deformity associated with Poland's syndrome was reconstructed in eight male patients 16 to 38 years old (average age 20 years). Follow-up ranged from 1 to 10 years. Two patients had custom silicone implants placed subcutaneously. In one of these patients, the edge of the implant could be seen. Three patients had transfer of an ipsilateral pedicled latissimus dorsi muscle flap with intact thoracodorsal nerve. All these patients had noticeable atrophy of the flap, and one underwent subsequent implantation of a custom silicone implant beneath the flap. Three other patients had a custom silicone implant covered immediately by a latissimus dorsi muscle flap. All four patients who had a combination of silicone implant and latissimus dorsi muscle flap had satisfactory correction of their deformity.

Adolescent↗
PubMed1990

Keratoacanthoma necessitating metacarpal amputation.

Keratoacanthoma is usually considered a benign self-limiting lesion. First described in 1888 by Hutchinson, it most commonly involves the face and hands. It is usually controlled by complete soft tissue excision. A variant, subungual keratoacanthoma, affects bone by pressure erosion of the distal phalangeal tip. We report a case of keratoacanthoma clinically involving a metacarpal and phalanges with a radiologic and physical appearance at variance with previous reports. After multiple recurrences following erosion and cryosurgery, as well as attempted digit salvage with Mohs' surgery, ray amputation was required. The world literature pertaining to keratoacanthoma is reviewed and discussed.

Aged↗
PubMed1990

Growth and adherence of xeroderma pigmentosum keratinocytes in vitro.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease in which cells are unable to repair ultraviolet light-induced DNA defects. Keratinocytes were obtained from the right medial leg of a 16-year-old girl with XP. Two donor sites were harvested: One was an obviously damaged area; the second was an area that had been harvested five years previously and now grossly appeared normal. The cells were plated on untreated plastic tissue culture dishes. All XP keratinocytes grew much faster and spread more rapidly than non-XP controls. There was a 1.5 to 2.5 times increase in the growth rate of XP cells from the obviously damaged area over XP cells from the normal-appearing area. The XP keratinocytes also showed an in vitro expressed alteration in adhesion compared with control keratinocytes, which appears to be independent of the cell growth rate.

Adolescent↗
PubMed1990

The fate of soluble steroids within breast prostheses in humans.

The long-term fate of 6-alpha-methyl-methylprednisolone hemisuccinate (MPHS) placed into breast prostheses prior to implantation in humans was determined. MPHS hydrolyzes to the active form 6-alpha-methylprednisolone (MP) in water, which then diffuses out of the implant. Twenty prostheses were recovered 5.3 to 34.7 months after placement, and the solution inside was analyzed for MPHS and MP. Half-lives were calculated for the hydrolysis of MPHS to MP (3.4 +/- 0.58 months [mean +/- SEM]) and for the diffusion of MP out of the prostheses (20.63 +/- 6.10 months). The large half-lives found imply that MPHS slowly hydrolyzes to MP, and that active steroid is released for a longer time than was previously thought. This long release could be the cause of the long-term effects seen with steroids used in this manner.

Breast↗