Dual Orbital Degeneracy Lifting in a Strongly Correlated Electron System

The local structure of NaTiSi_{2}O_{6} is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the transition. The analysis unravels that, on warming, the dimers evolve into a short range orbital degeneracy lifted (ODL) state of dual orbital character, persisting up to at least 490 K. The ODL state is correlated over the length scale spanning ∼6 sites of the Ti zigzag chains. Results imply that the ODL phenomenology extends to strongly correlated electron systems.

Local orbital degeneracy lifting as a precursor to an orbital-selective Peierls transition

Fundamental electronic principles underlying all transition metal compounds are the symmetry and filling of the d-electron orbitals and the influence of this filling on structural configurations and responses. Here we use a sensitive local structural technique, x-ray atomic pair distribution function analysis, to reveal the presence of fluctuating local-structural distortions at high temperature in one such compound, CuIr₂S₄. We show that this hitherto overlooked fluctuating symmetry-lowering is electronic in origin and will modify the energy-level spectrum and electronic and magnetic properties. The explanation is a local, fluctuating, orbital-degeneracy-lifted state. The natural extension of our result would be that this phenomenon is likely to be widespread amongst diverse classes of partially filled nominally degenerate d-electron systems, with potentially broad implications for our understanding of their properties.

A common feature of many transition metal materials is global symmetry breaking at low temperatures. Here the authors show that such materials are characterized by fluctuating symmetry-lowering distortions that exist pre-formed in higher temperature phases with greater average symmetry.

Robust Phonon-Plasmon Coupling in Quasifreestanding Graphene on Silicon Carbide

Using inelastic electron scattering in combination with dielectric theory simulations on differently prepared graphene layers on silicon carbide, we demonstrate that the coupling between the 2D plasmon of graphene and the surface optical phonon of the substrate cannot be quenched by modification of the interface via intercalation. The intercalation rather provides additional modes like, e.g., the silicon-hydrogen stretch mode in the case of hydrogen intercalation or the silicon-oxygen vibrations for water intercalation that couple to the 2D plasmons of graphene. Furthermore, in the case of bilayer graphene with broken inversion symmetry due to charge imbalance between the layers, we observe a similar coupling of the 2D plasmon to an internal infrared-active mode, the LO phonon mode. The coupling of graphene plasmons to vibrational modes of the substrate surface and internal infrared active modes is envisioned to provide an excellent tool for tailoring the plasmon band structure of monolayer and bilayer graphene for plasmonic devices such as plasmon filters or plasmonic waveguides. The rigidity of the effect furthermore suggests that it may be of importance for other 2D materials as well.

Laser resurfacing of the periorbital region

Laser skin resurfacing of the periorbital region can be performed as an isolated procedure, as part of a full-face resurfacing, or as an adjunct to procedures such as transconjunctival blepharoplasty. The two wavelengths in common use are pulsed carbon dioxide and erbium: yttrium aluminum garnet. The principles and techniques of using these lasers for periorbital resurfacing, as well as the practice of combining these wavelengths in sequence, are described. In addition, pre- and postprocedure measures are discussed.

Medicolegal aspects of imaging and Internet communications

Many facial plastic surgeons have set up their own personal World Wide Web (WWW) pages with an electronic mail link to communicate with and educate prospective patients. The possible dilemma is in that these services are provided without actually meeting patients face to face. Also, despite the growing popularity of computer imaging systems, it is not clear whether the medical and legal advantages of using such a system outweigh the disadvantages. The purpose of this article is to evaluate these aspects and to provide some protective guidelines. An examination of possible causes of actions arising from computer imaging suggests that surgeons who follow a few simple guidelines, and who use computer imaging responsibly and cautiously, minimize their legal liability. Issues surrounding Internet discussion groups, posted medical advice, intellectual property, and the use of an electronic mail link are also discussed.

Midfacial osteomyelitis in a chronic cocaine abuser: a case report

We describe the case of a 56-year-old man who was admitted for treatment of a progressive destruction of his hard palate, septum, nasal cartilage, and soft palate that had been caused by chronic cocaine inhalation. Biopsy of the bony septum revealed acute osteomyelitis and an extensive overgrowth of bacteria and Actinomyces-like organisms. There was no evidence of granuloma or neoplasm. The patient received intravenous ampicillin/sulbactam for 6 weeks, followed by lifetime oral amoxicillin. When there was no further evidence that destruction was progressing, the patient underwent nasal reconstruction with a cranial bone graft. The surgery was completed with no complications. To our knowledge, this is the first reported case of midfacial osteomyelitis associated with chronic cocaine abuse. The severity of this patient's complications, coupled with the success of his reconstructive surgery, makes this case particularly interesting. We believe that it is important for physicians to understand that septal perforation in a cocaine abuser should not be underestimated because it could result in a secondary bone infection. Nasoseptal destruction secondary to intranasal cocaine abuse is a result of cocaine's vasoconstrictive properties, and a decrease in the oxygen tension of intranasal tissue can facilitate the growth of anaerobic pathogens.

Effect of blended carbon dioxide and erbium:YAG laser energy on preauricular and ear lobule keloid fibroblast secretion of growth factors: a serum-free study

BACKGROUND

A serum-free in vitro model was used to determine the effect of combined carbon dioxide (CO2) and erbium (Er):YAG laser (Derma K; ESC/Sharplan Medical Systems, Yokneam, Israel) irradiation on keloid-producing fibroblasts (KFs) from 2 distinct facial sites. Transforming growth factor beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) play an integral part in wound healing and were assayed using this model. It has always been a clinical impression that fibroblasts from different regions of the face behave differently. This is exemplified by patients prone to lobule keloid formation after ear piercing, who heal normally after a facial incision.

DESIGN

Laboratory-based wound healing.

METHODS

Human KF cell lines were established from operative specimens using standard explant techniques. At 48 hours after seeding, 20% of each well was exposed to 1.7 J/pulse of Er:YAG laser energy and CO2 delivered at 3 or 5 W and at a duty cycle of 25%, 50%, or 100%. Using a quantitative enzyme-linked immunosorbent assay, TGF-beta1 and bFGF were assayed from collected supernatants.

RESULTS

Laser-treated ear lobule KFs demonstrated decreased TGF-beta1 production when compared with preauricular KFs. Statistical significance (P<.005) was seen in the 3-W CO2 25% duty cycle; a trend was seen in the 3-W CO2 50% duty cycle (P<.08). Preauricular KFs secreted increased bFGF when compared with lobule KFs. Significance was seen in the 3-W CO2 25% and 50% duty cycles (P<.05). Laser-treated preauricular KFs had increased bFGF secretion when compared with non-laser-treated preauricular KFs in the 3-W CO2 25%, 50%, and 100% duty cycles.

CONCLUSIONS

Combined CO2 and Er:YAG laser treatment decreases the production of TGF-beta1 in preauricular and ear lobule KFs. This laser may have clinical promise in the treatment of keloids. Finally, the different growth factor profiles obtained suggest that KFs from the ear lobule and preauricular regions are different.

Microdermabrasion

Microdermabrasion is a new skin resurfacing modality rapidly gaining popularity among the aesthetic surgery patient population. It produces a superficial wound to the skin, comparable with alpha hydroxy acid treatment clinically and histologically. Advantages include fast results, no anesthetic requirement, safety, and rapid recovery time. Equipment costs and training requirements are modest. Microdermabrasion will likely earn an important place in the skin resurfacing armamentarium.

Laser skin resurfacing

Laser skin resurfacing has become an important component of rejuvenation surgery. The two wavelengths in common use are: pulsed carbon dioxide and erbium:yttrium aluminum garnet. The principles and techniques of using these lasers for resurfacing and the practice of combining these wavelengths in sequence are described.

Effect of Tamoxifen on Transforming Growth Factor β1Production by Keloid and Fetal Fibroblasts

BACKGROUND

Evidence suggests that keloid scar formation may be mediated, in part, by deranged growth factor activity, including that of transforming growth factor (TGF) beta1. Tamoxifen citrate has shown promise in the treatment of keloids.

OBJECTIVE

To evaluate the effect of tamoxifen on autocrine growth factor expression in keloid and fetal dermal fibroblasts, which exhibit scar-free healing.

DESIGN

Serum-free cell lines of keloid and fetal dermal fibroblasts were established. Cell cultures were exposed to different concentrations of tamoxifen solution (8 and 12 or 16 micromol/L). Cell counts were performed and supernatants collected at 24, 48, and 96 hours. Cell-free supernatants were quantitatively assayed for TGF-beta1 expression.

RESULTS

Keloid fibroblasts show increased per-cell TGF-beta1 production compared with fetal fibroblasts. Tamoxifen appeared to decrease per-cell TGF-beta1 production at each of the time points evaluated.

CONCLUSIONS

Keloids likely arise due to locally insufficient or excessive concentrations of specific growth factors. The higher level of TGF-beta1 produced by keloid cells compared with fetal fibroblasts could be related to the aberrant wound healing seen with keloids. The addition of tamoxifen may lead to improved wound healing in keloids by decreasing the expression of TGF-beta1.

In vivo model of histologic changes after treatment with the superpulsed CO(2) laser, erbium:YAG laser, and blended lasers: a 4- to 6-month prospective histologic and clinical study

BACKGROUND AND OBJECTIVE

To compare the in vivo histologic effects of the pulsed carbon dioxide (CO(2)) and erbium:ytrium aluminum garnet (Er:YAG) lasers and to assess the effects of combining CO(2) and Er:YAG laser modalities during a single treatment session. We previously reported 10 patients treated with four laser regimens: CO(2) alone, CO(2)/Er:YAG, Er:YAG alone, Er:YAG/CO(2) with time points at 1 hour and 7 days between laser treatment and histologic analysis. This study found that the optimal treatment consisted of limited CO(2) laser passes followed by Er:YAG. This treatment produced less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration in the acute phase of healing. The present study examines the histologic changes resulting from the host healing response to laser treatment on long-term follow-up of 4-6 months.

STUDY DESIGN/MATERIALS AND METHODS

The Stanford University Committee on Human Subjects in Medical Research approved this study. Nine patients with actinic damage and indications for rhytidectomy volunteered for this interventional study in which each patient served as both experimental and control. The right preauricular area was treated at five sites with the following: (1) CO(2), (2) CO(2) followed by Er:YAG, (3) Er:YAG, (4) blended CO(2)/Er:YAG (Derma-Ktrade mark), (5) phenol. Each was subjected to full-face or sub-unit treatment. Each patient was followed up initially daily then weekly for healing of the full-face laser and for differences in healing of the five treatment areas. Five patients were selected for histologic evaluation. At 4-6 months, these patients underwent rhytidectomy with immediate removal of laser-treated skin, which was evaluated histologically by the study dermatopathologist, who was blinded to the treatment at each site.

RESULTS

CO(2) laser treatment produced the greatest thickness of neocollagen (0.27 mm; P < 0.05), the highest neocollagen density (P < 0.05), the greatest decrease in elastosis (27%), but took the longest time for healing and resolution of erythema and inflammation (up to 6 months). Er:YAG used alone produced the least collagen density, with the thinnest band of neocollagen (0.08 mm), but the most rapid resolution of erythema and inflammation (within 10 days). Combined CO(2)/Er:YAG treatments, including Derma-Ktrade mark and CO(2) followed by Er:YAG produced histologic changes that were intermediate, as well as recovery that was intermediate (resolution of erythema within 1 month); the development of neocollagen was greater in CO(2)-containing modalities than Er:YAG used alone by a statistically significant margin (P = 0.001). These histologic findings were corroborated by clinical correlation by examination of the five treatment spots in nine patients and in full-face treatments in 100 patients.

CONCLUSION

Collagenesis is greatest with CO(2) and least with Er:YAG. Elastosis decreased to the greatest degree with CO(2), least with erbium, and to an intermediate extent with blended CO(2)/Er:YAG regimens (sequential and Derma-K). These changes from control are statistically significant with all regimens (P < 0.05). Blended CO(2)/Er:YAG treatments provide an optimal combination of the benefits of CO(2) but with lesser erythema and healing delay. Clinical and histologic findings change over time for different treatments. Thus, long-term histology is critical for predicting results of treatment.

The effect of copper tripeptide and tretinoin on growth factor production in a serum-free fibroblast model

OBJECTIVE

To evaluate the effect of copper tripeptide and tretinoin on normal and keloid-producing dermal fibroblasts in a serum-free in vitro model. The cellular response was described in terms of viability and secretion of basic fibroblast growth factor (bFGF) and transforming growth factor-beta1 (TGF-beta1).

METHODS

Primary cell lines were established from patient facial skin samples obtained during surgery and plated in serum-free media. At 0 hour, copper tripeptide (1 x 10 (-9) mol/L), tretinoin (1 x 10 (-5) mol/L), or appropriate control vehicle was added. Cell counts and viability were established at 24, 72, and 120 hours. Supernatants were collected at the same intervals and were assessed for bFGF and TGF-beta1 concentrations using the enzyme-linked immunosorbent assay technique.

RESULTS

Cell lines showed viability between 86% and 96% (mean, 92%) throughout the experiment. Tretinoin-treated normal fibroblasts secreted more bFGF than did controls at 24 hours (P<.05). Tretinoin-treated keloid-producing fibroblasts secreted more TGF-beta1 than did controls at 120 hours (P<.05). Keloid-producing fibroblasts treated with copper tripeptide secreted less TGF-beta1 than did controls at 24 hours (P<.05); a similar trend was observed in normal fibroblasts.

CONCLUSIONS

Normal fibroblasts treated with tretinoin produced more bFGF than did controls, and this might partially explain the clinically observed tightening effects of tretinoin. Normal and keloid-producing dermal fibroblasts treated with copper tripeptide secreted less TGF-beta1 than did controls, suggesting a possible clinical use for decreasing excessive scar formation.

Histologic analysis of the thermal effect on epidermal and dermal structures following treatment with the superpulsed CO2 laser and the erbium: YAG laser: an in vivo study

BACKGROUND AND OBJECTIVE

To compare the in vivo histologic effects of the carbon dioxide (CO2) and erbium:yttrium aluminum garnet (Er:YAG) lasers. To ascertain the effects of combining CO2 and Er:YAG laser modalities during a single treatment session.

STUDY DESIGN/MATERIALS AND METHODS

Ten patients underwent laser treatment to four left preauricular sites 7 days prior to rhytidectomy as follows: CO2 alone, CO2/Er:YAG, Er:YAG alone, and Er:YAG/CO2. The right preauricular area was identically treated 1 hour prior to rhytidectomy. Laser treated skin was excised during rhytidectomy and was evaluated histopathologically in a blinded manner.

RESULTS

After 7 days, all groups were reepithelialized and showed equal neo-collagen formation. After 7 days, CO2/Er:YAG and Er:YAG alone had the least collagen injury and thickest epidermis and papillary dermis of all groups. Specimens lased 1 hour prior to excision showed the least collagen injury and thermal necrosis when treated with CO2/Er:YAG and Er:YAG alone. Four passes with CO2 removed 250 microm of tissue, while eight passes with the Er:YAG removed 160 microm of tissue.

CONCLUSIONS

Limiting CO2 laser passes and ending with Er:YAG produces less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration. CO2 followed by Er:YAG has similar thermal necrosis and collagen injury as Er:YAG alone, presumably due to Er:YAG removal of CO2 induced thermal injury.

Review of closed dressings after laser resurfacing

BACKGROUND

Laser skin resurfacing has become an accepted technique for the treatment of facial rhytides and associated solar skin damage. Achieving a successful result is directly related to proper postoperative wound care during the reepithelialization process. There are open and closed approaches to the treatment of the post-laser resurfacing patient with distinct advantages and disadvantages.

OBJECTIVE

To review the most commonly used closed dressings after facial laser skin resurfacing and compare their advantages and disadvantages. To compare clinical findings with a group of patients treated exclusively with an open technique.

METHODS

Review of composite foams, polymer film, polymer mesh, and hydrogel products and prospective observations of clinical outcomes of patients treated with each dressing category after facial laser skin resurfacing. We perform a retrospective chart review of a group of patients treated exclusively with an open technique comparing crust formation, comfort, and pruritus with the prospective group of patients treated with closed dressings.

RESULTS

The closed dressings available today each have unique structural configurations and adhesive properties intended to maintain an occlusive wound environment. Patient acceptance of these dressings was favorable, with improved comfort compared to the open dressing group. Complications of bacterial infections and contact dermatitis were not observed when closed dressings were used with a protocol for dressing changes performed at 48 hours. Rates of reepithelialization did not vary according to dressing category. Crust formation and postoperative pruritus occurred less frequently when closed occlusive dressings were worn by patients.

CONCLUSIONS

When used properly, these dressings improve patient comfort, simplify their postoperative wound care, and do not increase the risk of infection or contact dermatitis. Overall satisfaction was highest with perforated mesh and polymer dressings for full-face wounds.

Growth of tissue-engineered human nasoseptal cartilage in simulated microgravity

OBJECTIVE

To evaluate the feasibility of in vitro fabrication of tissue-engineered cartilage from human nasoseptal chondrocytes for autologous reconstruction.

DESIGN

Hyaline cartilage was reconstituted from chondrocyte-polyglycolic acid scaffolding constructs in a 3-dimensional mammalian cell culture cascade. This included monolayer cellular amplification, cell seeding in the spinner flask, and tissue growth in simulated microgravity.

RESULTS

The quality of the fabricated cartilage analogue was found to depend on the initial cell density, duration of incubation, and bioreactor type. Dynamic seeding was nearly completed within the first 10 hours of inoculation regardless of the cell source (cryogenically preserved vs fresh chondrocytes) or presence of serum. A duration of incubation in excess of 4 weeks was required for complete matrix biosynthesis at low seeding densities in the spinner flasks. Seeding densities greater than 2.3x10(6) chondrocytes per scaffold were required for early hyaline cartilage formation as well as longer-time mature matrix regeneration. In addition, maintaining the structural integrity of the unreinforced scaffold, which is necessary for continued mature matrix regeneration, was achievable through postseeding tissue growth in simulated microgravity.

CONCLUSION

Once combined with polyglycolic acid scaffolds in the bioreactor cascades that allow efficient seeding and quiescent tissue growth, human septal chondrocytes become a valuable source of reproducible ex vivo cartilage regeneration in the laboratory.

The effect of superpulsed carbon dioxide laser energy on keloid and normal dermal fibroblast secretion of growth factors: a serum-free study

An in vitro model was used to determine the effect of superpulsed CO2 laser energy on normal dermal and keloid-producing fibroblast proliferation and release of growth factors. Growth factors assayed included basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1). bFGF is mitogenic, inhibits collagen production, and stabilizes cellular phenotype. TGF-beta1 stimulates growth and collagen secretion and is thought to be integral to keloid formation. Growth in a serum-free medium allowed measurement of these growth factors without confounding variables. Keloid and normal dermal fibroblasts cell lines were established from facial skin samples using standard explant techniques. Samples consisted of three separate keloid and three separate normal dermal fibroblast cell lines. Cells were used at passage 4 to seed 24-well trays at a concentration of 6 x 10(4) cells per milliliter in serum-free medium. At 48 hours, 18.8 percent of each cell well was exposed to a fluence of 2.4, 4.7, and 7.3 J/cm2 using the superpulsed CO2 laser. Cell viability and counts were established at four time points: 0 (time of superpulsed CO2 laser treatment), 24, 72, and 120 hours. Supernatants were collected and assessed for bFGF and TGF-beta1 using a sandwich enzyme immunoassay. All cell lines demonstrated logarithmic growth through 120 hours (conclusion of experiment), with a statistically significant shorter population doubling time for keloid fibroblasts (p < 0.05). Use of the superpulsed CO2 laser shortened population doubling times relative to that of controls; the differences were statistically significant in keloid dermal fibroblasts when fluences of 2.4 and 4.7 J/cm2 were used (p < 0.05 and 0.01, respectively). bFGF was present in greater levels in normal dermal fibroblasts than in keloid dermal fibroblasts. Application of superpulsed CO2 demonstrated a trend toward increased bFGF secretion in both fibroblast types; the increase was significant in the keloid group at 4.7J/cm2. A consistent trend in suppression of TGF-beta1 was seen in both groups exposed to superpulsed CO2, with the maximal effect occurring at 4.7 J/cm2. Serum-free culture sustains logarithmic cell growth and allows growth factor measurement without confounding variables from serum-containing media. Superpulsed CO2 enhances fibroblast replication and seems to stimulate bFGF secretion and to inhibit TGF-beta1 secretion. Given the function of these growth factors, the application of superpulsed CO2 may support normalized wound healing. These findings may explain the beneficial effects of laser resurfacing on a cellular level and support the use of superpulsed CO2 in the management of keloid scar tissue.

Prevention and correction of temporal hair loss in rhytidectomy

Routine incisions in the temporal area for rhytidectomy often remove hair-bearing skin anterior to the ear. This results in a cosmetic deformity, making the surgical intervention clearly visible. This is especially problematic for revision rhytidectomy or for patients with naturally high hairlines. This article describes a systematic approach to the temporal hairline and introduces a novel, hair-bearing, transposition flap that corrects iatrogenic loss of the preauricular tuft of hair.

Efficacy of octyl-2-cyanoacrylate tissue glue in blepharoplasty. A prospective controlled study of wound-healing characteristics

OBJECTIVE

To compare the surgical efficacy and wound-healing characteristics of the tissue adhesive octyl-2-cyanoacrylate (approved by the Food and Drug Administration) with traditional suture closure in upper blepharoplasty.

METHODS

Prospective, randomized, blinded study comparing cosmetic and functional outcome and time efficiency. Twenty subjects underwent upper eyelid blepharoplasty. Each patient had a control side and an experimental side determined randomly. One eyelid incision was closed with octyl-2-cyanoacrylate (Dermabond; Ethicon Inc, Somerville, NJ) tissue glue, and the other with 6.0 suture (polypropylene or fast-absorbing gut). Comparisons were performed for the time for closure by each method, wound healing, and patient satisfaction. Macrophotographs of the wounds at 1, 2, and 4 weeks after surgery were graded by 5 observers blinded to the closure method, using a 10-point scale and a modified Hollander wound evaluation scale.

RESULTS

No statistically significant difference was found between the quality of octyl-2-cyanoacrylate closure and suture closure at 1 month. There were no differences in wound complications, duration of healing, inflammation, or final incision appearance. By 2 weeks, the sides were indistinguishable in 15 (75%) of the patients. Time for closure averaged 7 minutes with suture and 8 minutes with glue.

CONCLUSIONS

Octyl-2-cyanoacrylate glue is an excellent alternative to suture closure, producing equivalent quality of closure at all time points and no difference in appearance. This adhesive was sufficient to withstand the forces of closure in upper eyelid blepharoplasty without dehiscence in the absence of sutures.

Quantification of skin elasticity changes associated with pulsed carbon dioxide laser skin resurfacing

BACKGROUND

While skin resurfacing using pulsed carbon dioxide lasers appears to have a skin-tightening effect clinically, the debate continues over its actual effects on dermal collagen.

OBJECTIVES

To provide quantitative measures of skin elasticity changes associated with pulsed carbon dioxide laser skin resurfacing and to introduce to the facial plastic surgery community the Cutometer SEM 575 skin elasticity meter, an instrument that is useful in the measurement of skin elasticity.

SETTING

University-based facial plastic surgery clinic and wound healing laboratory.

DESIGN

Intervention.

MAIN OUTCOME MEASURES

Measurements taken prior to and 6 months after procedure.

SUBJECTS AND INTERVENTION

Thirty-two patients undergoing pulsed carbon dioxide full-face laser skin resurfacing participated. There were 12 test sites measured in 6 aesthetic units per participant. The Cutometer SEM 575 skin elasticity meter was used to measure skin elasticity changes accompanying this procedure. This device measures skin deformation with an accuracy of 10 microns.

RESULTS

The change in elastic recovery (Ur/Ue) was determined. At all 6 of the facial sites, there was a statistically significant increase in skin elasticity (P < .001). Overall, there was an 18.2% improvement in skin elasticity. Site-specific changes ranged from 9% (forehead) to 22% (prejowl and periorbital).

CONCLUSIONS

Skin resurfacing with the pulsed carbon dioxide laser produces a true skin-tightening effect. The Cutometer is a valuable instrument that permits accurate quantification of skin elasticity and may be useful in the evaluation of other facial plastic procedure results.

The validity of ex vivo laser skin treatment for histological analysis. A prospective controlled study

BACKGROUND

Laser treatment of skin following removal from human subjects has been the staple of laser research. However, no study has been done to assess the efficacy of ex vivo skin for predicting the behavior of laser treatments in living human tissue.

OBJECTIVE

To assess the validity of the ex vivo model by comparing histological characteristics of skin treated with laser prior to and following its removal in rhytidectomy.

STUDY DESIGN

Nonrandomized controlled intervention study in which each patient served as both experimental subject and control for different skin sites.

PATIENTS

Ten patients with actinic skin changes.

INTERVENTIONS

Patients underwent laser treatment to 4 left preauricular sites 1 hour prior to rhytidectomy as follows: carbon dioxide laser treatment alone, carbon dioxide laser treatment followed by erbium:YAG laser treatment, erbium:YAG laser treatment alone, and erbium:YAG laser treatment followed by carbon dioxide laser treatment. The skin was examined by a dermatopathologist blinded to the identity of each specimen. Untreated skin was also removed and immediately subjected to laser treatment identical to that employed in the in vivo skin. This skin was examined histologically.

MAIN OUTCOME MEASURES

Regularity of ablation, depth of the necrotic zone, amount of skin removed, degree of collagen injury, and degree of inflammation.

RESULTS

There were significant differences between the ex vivo and in vivo groups. The ex vivo specimens demonstrated more than 10 times the irregularity of ablation of the in vivo specimens (irregularity index of 3.0 for the ex vivo group vs 0.25 for the in vivo specimens; P < .05). The incidence of collagen injury was slightly lower for the ex vivo group (1.0 vs 1.3), as was the degree of inflammation (1.4 vs 1.5). The greatest differences were the significantly smaller necrotic zone in the ex vivo specimens (51 vs 71 microns) and the smaller amount of skin removed (118 vs 234 microns). These findings were consistent for all 4 laser treatment regimens studied.

CONCLUSIONS

Significant differences were found between the in vivo and ex vivo models. Irregularity of ablation in the ex vivo specimens was 10 times that in the living specimens, limiting histological accuracy in the ex vivo model. The ex vivo skin model underestimated the amount of tissue ablation. This suggests that an in vivo model should be adopted as the standard for laser research.

Delayed radionecrosis of the larynx

Radiation has been used to treat carcinoma of the larynx for more than 70 years. Radionecrosis is a well-known complication of this modality when treating head and neck neoplasms. It has been described in the temporal bone, midface, mandible, and larynx. Laryngeal radionecrosis is manifested clinically by dysphagia, odynophagia, respiratory obstruction, hoarseness, and recurrent aspiration. The vast majority of patients who develop laryngeal radionecrosis present with these symptoms within 1 year of treatment; however, delayed presentations have been reported up to 25 years after radiotherapy. We present, in a retrospective case analysis, an unusual case of laryngeal radionecrosis in a patient who presented more than 50 years after treatment with radiotherapy for carcinoma of the larynx. The cases of delayed laryngeal necrosis in the literature are presented. This represents the longest interval between treatment and presentation in the literature. The details of the presentation, clinical course, and diagnostic imaging are discussed. The pathogenesis, clinical features, and treatment options for this rare complication are reviewed. Early stage (Chandler I and II) laryngeal radionecrosis may be treated conservatively and often observed. Late stage (Chandler III and IV) cases are medical emergencies, occasionally resulting in significant morbidity or mortality. Aggressive diagnostic and treatment measures must be implemented in these cases to improve outcome. This case represents the longest interval between initial treatment and presentation of osteoradionecrosis in the literature. A structured diagnostic and therapeutic approach is essential in managing this difficult problem.

Controversies in the management of inferior turbinate hypertrophy: a comprehensive review

Nasal obstruction must frequently be addressed during functional rhinoplasty. Even after a properly performed septorhinoplasty correcting septal deflection and/or nasal valve collapse, nasal obstruction may persist due to turbinate hypertrophy. Turbinates have many important functions, including warming and humidification of inspired air, and numerous factors can contribute to pathologic enlargement. Management of inferior turbinate hypertrophy has been actively debated for more than a century. The primary goal of therapy is to maximize the nasal airway for as extended a period as possible while minimizing complications of therapy, such as nasal drying and hemorrhage. This review describes the various medical and surgical therapeutic modalities widely used today, with emphasis placed on surgical management of the inferior turbinates. Advantages, disadvantages, complications, and controversies of each form of treatment are reviewed and discussed. A staged protocol of increasingly invasive interventions is proposed.

Basic fibroblast growth factor and insulinlike growth factor I support the growth of human septal chondrocytes in a serum-free environment

OBJECTIVE

To determine if insulinlike growth factor I (IGF-I) and basic fibroblast growth factor (bFGF), individually or in combination, support the growth and viability of human septal chondrocytes in a serum-free medium (SFM) and a serum-enhanced culture medium.

DESIGN

Chondrocytes were recovered from enzymatically digested human septal cartilage and were plated for monolayer culture in a newly developed medium. The medium included Dulbecco modified Eagle medium mixed 1:1 with Ham F12 medium and a supplement of known amounts of 2 growth factors-bFGF (100 ng/mL) and IGF-I (100 ng/mL)-used in combination and separately.

RESULTS

The combination of IGF-I and bFGF enhanced chondrocyte growth and maintained a high degree of viability in SFM and 10% fetal calf serum. After an initial lag, the SFM, augmented with both growth factors, produced a comparable number of viable cells (4.25+/-0.31 x 10(4)) to that of the medium with 10% fetal calf serum (4.64+/-0.35 x 10(4)) by the seventh day of the experiment. Combined with the 2 growth factors, 10% fetal calf serum provided the greatest proliferation by the end of the experiment. However, the overall mean cell counts for the IGF-I- and bFGF-enhanced SFM were not statistically different.

CONCLUSIONS

The combination of IGF-I and bFGF in a serum-free and a serum-supplemented environment supports the growth and viability of human septal chondrocytes in short-term culture. In an SFM, the results obtained approximate those produced in a medium enhanced with 10% fetal calf serum.

Direct bonded orthodontic brackets for maxillomandibular fixation

OBJECTIVES/HYPOTHESIS

Mandibular fracture treatment often includes arch bar maxillomandibular fixation (MMF), either alone or in combination with open reduction/internal fixation (ORIF) techniques. The glove perforation rate associated with arch bar placement, the incidence of blood-borne pathogen positivity in facial fracture patients, and the injurious effects of arch bars on dental enamel and gingiva have prompted the development of safer alternatives to arch bar MMF. This study evaluates the efficacy, ease of use, and safety profile of one such alternative: orthodontic direct bonded bracket fixation (MMF/DBB).

STUDY DESIGN

Prospective study of consecutive mandible fracture patients treated with MMF/DBB.

METHODS

Thirty-two patients with mandibular fractures were evaluated from January 1994 to July 1997. Fourteen were appropriate for treatment with MMF/DBB (12 men and two woman; mean age, 24.6+/-7.2 y; range, 16-42 y). Fracture sites included symphysis, angle, condylar neck, coronoid, and body. Nine patients underwent MMF/DBB alone; five underwent MMF/DBB with subsequent ORIF.

RESULTS

No infection, malocclusion, malunion/nonunion, or enamel/ gingiva injury occurred. Mean follow-up was 6 months (range, 1-12 mo). Oral hygiene with MMF/DBB was superior to historical controls using arch bars.

CONCLUSIONS

MMF/DBB can serve as the single treatment method with satisfactory results in patients with favorable, less complicated mandible fractures, although with increased experience, we have treated several more complex cases with MMF/DBB alone. In cases necessitating ORIF, MMF/DBB can be performed preoperatively to align fracture segments and reestablish occlusion. This facilitates placement of osteosynthesis plates and reduces ORIF operative time. MMF/DBB is an economical, safe technique that minimizes blood-borne-pathogen risk to the operative team, eliminates periodontal injury, facilitates postoperative dental hygiene, and is painless to apply and remove.

The failing flap in facial plastic and reconstructive surgery: role of the medicinal leech

OBJECTIVE

To review the use of the medicinal leech, Hirudo medicinalis, in salvaging the failing, venous-congested flap. A protocol for the use of leeches is presented. Four illustrative cases of failing flaps (pectoralis major, midline forehead, and temporalis) are presented.

STUDY DESIGN

Literature review comprised of MEDLINE search 1965 to present. Retrospective review of four cases involving the management of the failing, venous-congested flap.

METHODS

A retrospective review of four cases of failing, venous-congested flaps was performed.

RESULTS

The authors' experience, as well as the data from the reviewed medical literature, demonstrates the importance of early intervention in order to salvage the failing, venous-congested flap. Leeches are an immediate and efficacious treatment option.

CONCLUSIONS

1. Review of the literature indicates that the survival of the compromised, venous-congested flap is improved by early intervention with the medicinal leech. H medicinalis injects salivary components that inhibit both platelet aggregation and the coagulation cascade. The flap is decongested initially as the leech extracts blood and is further decongested as the bite wound oozes after the leech detaches. 2. When a flap begins to fail, salvage of that flap demands early recognition of reversible processes, such as venous congestion. The surgeon must be familiar with the use of leeches and should consider their use early, since flaps demonstrate significantly decreased survival after 3 hours if venous congestion is not relieved. In the four cases presented, a standardized protocol facilitated early leech use and provided for the psychological preparation of the patient, availability of leeches, and an antibiotic prophylaxis regimen. 3. The complications associated with leech use can be minimized with antibiotic therapy, wound care, and hematocrit monitoring. 4. The use of the medicinal leech for salvage of the venous-congested flap is a safe, efficacious, economical, and well-tolerated intervention.

Closed dressings after laser skin resurfacing

OBJECTIVE

To evaluate the safety, efficacy, and patient acceptance of closed dressings after full facial resurfacing with the carbon dioxide laser.

DESIGN

Prospective cohort of men and women undergoing full facial carbon dioxide laser resurfacing.

SETTING

Ambulatory surgical center at a university hospital.

PATIENTS

Forty consecutive patients randomized to 1 of 4 dressing groups.

INTERVENTIONS

All patients underwent full facial resurfacing with a carbon dioxide laser system. One of 5 closed dressings (single- or 3-layer composite foam, plastic mesh, hydrogel, or polymer film) was placed immediately after the procedure. Closed dressings were changed on postoperative day 2 and removed on postoperative day 4.

OUTCOME MEASURES

Objective postoperative criteria of erythema, scarring, reepithelialization, and surface irregularities were recorded and photodocumented. Comparisons were made among the closed dressing groups as well as with a group of historical control subjects treated with open dressings. The ease of application, office time for preparation and application, and cost of the individual dressings were collected. Patient characteristics of overall acceptance, comfort, and ease of maintenance were recorded with a visual analog scale.

RESULTS

There were no complications of scarring, surface irregularities, or contact dermatitis from the application or maintenance of the closed dressings. There were no significant differences in the number of days of postoperative erythema or in the rate of facial reepithelialization among the groups. Most patients preferred not to continue with the closed dressings past 2 days. Positive features from the use of closed dressings included reduction in crust formation, decreased pruritus, decreased erythema, and decreased postoperative pain, compared with historical controls. Negative features included time in preparation and application of the dressings. Costs ranged from $9.79 to $50 per dressing change.

CONCLUSIONS

Closed dressings are safe and offer benefits noted during the first 4 postoperative days. Patients can be expected to maintain a closed dressing for at least 24 hours but no longer than 4 days. The positive features of closed dressings and patient acceptance outweigh the cost and office time involved with their application and maintenance.

Initial clinical evaluation of the NovaScan carbon dioxide laser handpiece

BACKGROUND

This report summarizes an institutional review board-approved 6-month study with the NovaPulse carbon dioxide (CO2) laser utilizing the NovaScan handpiece in facial skin resurfacing applications.

OBJECTIVE

This study comprised the initial clinical evaluation (pre-FDA approval) of this device.

METHODS

A total of 54 patients underwent 56 laser procedures: 36 full face and 20 regional procedures.

RESULTS

Following healing, there was a 91% satisfaction rate. The mean laser-on times were: full face, 27 min; perioral, 7 min; periorbital, 3 min; glabellar, 2.5 min; scar, 5 min; and epidermal lesions, 6 min.

CONCLUSIONS

The NovaScan CO2 laser handpiece is a safe tool for skin resurfacing. In its initial use over a 6-month period there were no device-related complications.

Advantages and disadvantages of computer imaging in cosmetic surgery

BACKGROUND

Despite the growing popularity of computer imaging systems, it is not clear whether the medical and legal advantages of using such a system outweigh the disadvantages.

OBJECTIVE

The purpose of this report is to evaluate these aspects, and provide some protective guidelines in the use of computer imaging in cosmetic surgery.

METHODS

The positive and negative aspects of computer imaging from a medical and legal perspective are reviewed. Also, specific issues are examined by a legal panel.

RESULTS

The greatest advantages are potential problem patient exclusion, and enhanced physician-patient communication. Disadvantages include cost, user learning curve, and potential liability.

CONCLUSION

Careful use of computer imaging should actually reduce one's liability when all aspects are considered. Recommendations for such use and specific legal issues are discussed.

CD4+ T cells from IRF-1-deficient mice exhibit altered patterns of cytokine expression and cell subset homeostasis

Interferon regulatory factor-1 (IRF-1) is a member of a family of transcription factors that regulate an array of genes involved in cell growth, differentiation, and death. Analysis of cytokine expression by stimulated CD4+ cells from IRF-1(-/-) and IRF-1(+/+) mice revealed that IRF-1 deficiency resulted in an elevated production of Th2-related cytokines and a compensatory decrease in the expression of naive cell- and Th1-related cytokines. The altered cytokine profiles of IRF-1(-/-) cells could be explained, in part, by a shift in the representation of subsets of CD4+ cells; IRF-1(-/-) mice exhibited a decreased percentage of naive cells (a major source of IL-2) but increased numbers of memory or effector cells (the source of Th2-related cytokines). We analyzed purified, phenotypically matched memory/effector cells from IRF-1(-/-) and IRF-1(+/+) mice and found that the increased Th2:Th1 cytokine ratio was still evident in the IRF-1(-/-) group, thus suggesting that IRF-1 is involved in the polarization of the cytokine repertoire in CD4+ cells. Our data indicate that IRF-1 plays an important role in the maintenance of CD4+ cell subset homeostasis and in the expression of cytokines by naive and memory/effector cells.

CD4+ T cells from IRF-1-deficient mice exhibit altered patterns of cytokine expression and cell subset homeostasis

Interferon regulatory factor-1 (IRF-1) is a member of a family of transcription factors that regulate an array of genes involved in cell growth, differentiation, and death. Analysis of cytokine expression by stimulated CD4+ cells from IRF-1(-/-) and IRF-1(+/+) mice revealed that IRF-1 deficiency resulted in an elevated production of Th2-related cytokines and a compensatory decrease in the expression of naive cell- and Th1-related cytokines. The altered cytokine profiles of IRF-1(-/-) cells could be explained, in part, by a shift in the representation of subsets of CD4+ cells; IRF-1(-/-) mice exhibited a decreased percentage of naive cells (a major source of IL-2) but increased numbers of memory or effector cells (the source of Th2-related cytokines). We analyzed purified, phenotypically matched memory/effector cells from IRF-1(-/-) and IRF-1(+/+) mice and found that the increased Th2:Th1 cytokine ratio was still evident in the IRF-1(-/-) group, thus suggesting that IRF-1 is involved in the polarization of the cytokine repertoire in CD4+ cells. Our data indicate that IRF-1 plays an important role in the maintenance of CD4+ cell subset homeostasis and in the expression of cytokines by naive and memory/effector cells.

Legal issues of computer imaging in plastic surgery: a primer

Although plastic surgeons are increasingly incorporating computer imaging techniques into their practices, many fear the possibility of legally binding themselves to achieve surgical results identical to those reflected in computer images. Computer imaging allows surgeons to manipulate digital photographs of patients to project possible surgical outcomes. Some of the many benefits imaging techniques pose include improving doctor-patient communication, facilitating the education and training of residents, and reducing administrative and storage costs. Despite the many advantages computer imaging systems offer, however, surgeons understandably worry that imaging systems expose them to immense legal liability. The possible exploitation of computer imaging by novice surgeons as a marketing tool, coupled with the lack of consensus regarding the treatment of computer images, adds to the concern of surgeons. A careful analysis of the law, however, reveals that surgeons who use computer imaging carefully and conservatively, and adopt a few simple precautions, substantially reduce their vulnerability to legal claims. In particular, surgeons face possible claims of implied contract, failure to instruct, and malpractice from their use or failure to use computer imaging. Nevertheless, legal and practical obstacles frustrate each of those causes of actions. Moreover, surgeons who incorporate a few simple safeguards into their practice may further reduce their legal susceptibility.

Distortion of the auriculocephalic angle following rhytidectomy. Recognition and prevention

Distortion of ear protrusion after rhytidectomy results in an aesthetically unfavorable appearance. We have seen cases in which the auriculocephalic angle has widened postoperatively, producing a noticeable deformity. Herein, we report 3 cases that resulted in abnormal postsurgical ear protrusion. We also discuss prevention through the use of conchal setback sutures.

Contemporary management of the aging brow and forehead

Management of the aging brow and forehead has recently evolved based on available innovative technologies. Likewise, procedure-specific indications have changed based on collective surgical experiences. No longer is the approach based solely on hair pattern or degree of brow ptosis. Patients require varying combinations of brow elevation (prior to blepharoplasty), correction of brow asymmetries, and hairline-preserving forehead elevation. Some may only require excisional or paralytic procedures of the frontalis muscle (horizontal forehead creases), corrugator supercilii muscles (vertical glabellar furrows), and procerus muscle (horizontal glabellar furrows). We present a 3-year experience using a problem-specific approach. This incorporates endoscopic technology, botulinum toxin type A purified neurotoxin complex (Botox, Allergan, Irvine, CA) intramuscular injection, and traditional procedures such as the coronal, pretrichial, midforehead, and direct browlift. Current indications, patient selection, and results are also discussed.

Serum-free keloid fibroblast cell culture: an in vitro model for the study of aberrant wound healing

The purpose of this study was to develop an in vitro serum-free keloid fibroblast model. Keloid formation remains a problem for every surgeon. Prior evaluations of fibroblast characteristics in vitro, especially those of growth factor measurement, have been confounded by the presence of serum-containing tissue culture media. The serum itself contains growth factors, yet has been a "necessary evil" to sustain cell growth. The design of this study is laboratory-based and uses keloid fibroblasts obtained from five patients undergoing facial (ear lobule) keloid removal in a university-affiliated clinic. Keloid fibroblasts were established in primary cell culture and then propagated in a serum-free environment. The main outcome measures included sustained keloid fibroblast growth and viability, which was comparable to serum-based models. The keloid fibroblast cell cultures exhibited logarithmic growth, sustained a high cellular viability, maintained a monolayer, and displayed contact inhibition. Demonstrating model consistency, there was no statistically significant difference between the mean cell counts of the five keloid fibroblast cell lines at each experimental time point. The in vitro growth of keloid fibroblasts in a serum-free model has not been done previous to this study. The results of this study indicate that the proliferative characteristics described are comparable to those of serum-based models. The described model will facilitate the evaluation of potential wound healing modulators, and cellular effects and collagen modifications of laser resurfacing techniques, and may serve as a harvest source for contaminant-free fibroblast autoimplants. Perhaps its greatest utility will be in the evaluation of endogenous and exogenous growth factors.

Transcalvarial suture fixation for endoscopic brow and forehead lifts

OBJECTIVE

To evaluate the safety and effectiveness of transcalvarial suture fixation during endoscopic repair of brow ptosis.

DESIGN

Case series.

SETTINGS

A private ambulatory surgicenter and a Veterans Affairs Hospital.

PARTICIPANTS

Fifty patients with brow ptosis with minimum follow-up of 12 months.

RESULTS

Patients had improvement in brow position in all cases. There were no adverse effects of performing cortical tunnels and suture fixation.

CONCLUSION

Transcalvarial suture fixation can be performed safely with good to excellent results and avoids the need for screw or plate fixation.

Combined use of superpulsed carbon dioxide laser and cryotherapy for treatment of facial rhytids

OBJECTIVE

To compare the effect of superpulsed carbon dioxide (CO2) laser alone with that of cryotherapy in combination with CO2 laser in treatment of facial rhytids.

DESIGN

A randomized prospective study.

SETTING

Facial Plastic Surgery Clinic at Standford University Medical Center, Standford, Calif.

PATIENTS

Twenty patients with perioral rhytids were randomized in the study, 11 in the laser group and 9 in the cryotherapy and laser group.

INTERVENTION

Patients in the laser group were treated with superpulsed CO2 laser. Initially, the shoulders of rhytids were spot treated. The area was then wiped and rehydrated. The entire surface was then treated with a second pass. A third pass, if deemed necessary, was then used to treat the shoulders. Patients in the combined group underwent cryotherapy of the entire perioral region followed by CO2 laser treatment similar to that previously described.

MAIN OUTCOME MEASURE

Improvement in facial rhytids with laser treatment alone was compared with improvement using cryotherapy and laser. A skin wrinkle grading system was used and patients were graded by 3 independent observers. Close-up photographs were obtained preoperatively and postoperatively. A questionnaire was filled out by each patient 1 month following treatment and was used to rate overall patient satisfaction.

RESULTS

There was no statistically significant difference between the 2 groups regarding final outcome, amount of anesthetic agents required for each patient, or rate of complications.

CONCLUSION

Superpulsed CO2 skin resurfacing alone is as effective as combined cryotherapy and superpulsed CO2 laser for treatment of perioral rhytids.

Access to the superior mediastinum

Surgical access for diseases that involve the superior mediastinum can be achieved without thoracotomy by utilizing the suprasternal approach with extension of the head and neck and transection of the interclavicular ligament, median sternotomy, resection of the medial third to one half of the clavicle, or resection of the manubrium sterni. There has been minimal morbidity and no operative or postoperative mortality in a review of 53 consecutive patients. There has been no significant disability. Combined with exposure at the base of the neck, the access to the superior mediastinum is good to excellent.

Qualitative and quantitative immunoglobulin production by specific bacteria in chronic tonsillar disease

Tonsillar tissue lymphocyte (TTL) function as measured by immunoglobulin production was assessed in vitro in 60 tonsils, 51 diseased and 9 normal controls. The diseased specimens were from children (aged 3 to 10 years) clinically classified as having recurrent tonsillitis (RT), idiopathic tonsillar hyperplasia (ITH), or recurrent tonsillitis with hyperplasia (RT/H). TTLs were challenged with intact, heat-inactivated bacteria found in the core of diseased tonsils--Streptococcus pyogenes (SP) and Haemophilus influenzae type B (HIB) as well as the dominant bacterium (DB) grown from that particular tonsillar core. The phytomitogen, leukoagglutinin (LA), was used as a nonspecific activator. Qualitative immunoglobulin production was assessed for the immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) classes. Immunoglobulin-specific production was quantified at the basal level, and at 2, 4, and 6 days following stimulation. Stimulation with HIB produced the greatest amount of IgG and IgM in TTLs from control tonsils. The DB was a relatively weak stimulator of normal (control) TTLs, yet produced relatively brisk IgG responses in the RT and ITH categories. It did, however, yield only marginal IgM secretion in these groups. IgA was consistently produced after stimulation in diseased TTLs, yet was not elicited from normal TTLs. The aforementioned findings suggest a differential qualitative and quantitative immunoglobulin response for healthy, recurrently infected, and hyperplastic tonsils. Lymphocyte hypofunction along with structural changes associated with hyperplasia may be central to the etiology of chronic tonsillar disease. The tonsillar immunologic response in disease and health is discussed.

Effect of specific bacteria on lymphocyte proliferation in diseased and nondiseased tonsils

Tonsillar tissue lymphocyte (TTL) function as measured by lymphocyte proliferation was assessed in vitro in 38 tonsils--30 diseased and 8 normal controls. TTLs from diseased and control tonsils were challenged with intact, heat-inactivated bacteria which may be found in the core of diseased tonsils; these bacteria were Streptococcus pyogenes and Hemophilus influenzae type B (HIB), as well as the dominant bacterium (DB) grown from that particular tonsillar core. The phytomitogen leukoagglutinin (LA) was used as a nonspecific activator. Lymphocyte proliferation was quantified and reported using a stimulation index (SI) which was based upon viable cell counts at 2, 4, and 6 days following inoculation. Overall, the greatest degree of lymphocyte proliferation in diseased TTLs (SI = .91) was produced by HIB. However, both SP and HIB produced more lymphocyte proliferation in the nondiseased TTLs than in the diseased TTLs (P < .01). H influenzae (non-B) and group A beta-hemolytic streptococci were the pathogens most frequently cultured as the dominant bacteria from the core of diseased tonsils; Streptococcus viridans was most frequently cultured in nondiseased tonsils. The DB caused greater TTL proliferation in diseased (SI = .89) versus control (SI = .63) TTLs (P < .001). These findings suggest a differential proliferative response in vitro for diseased and nondiseased TTLs in response to specific bacteria. The role of possibly pathogenic bacteria and commensals, as well as the implications for clinical disease, are discussed.

Bacteriology and immunology of normal and diseased adenoids in children

Adenoid physiology as reflected in the qualitative and quantitative bacteriology and immune cell distribution was correlated with clinical presentation in 69 children (16 to 130 months of age) undergoing adenoidectomy for obstructive adenoid hyperplasia (n = 38) or chronic adenoid infection (n = 31) and in 16 adenoid core biopsy specimens from 16 nondiseased controls. In the control adenoids, few potentially pathogenic bacteria were found as the dominant bacteria in the adenoid core (25%), and significantly greater concentrations of nonpathogens (commensals) were isolated (P < .01). Potential pathogens as the dominant bacteria were found twice as often in obstructive adenoid hyperplasia (62%) and in chronic adenoid infection (55%) (P < .05). Haemophilus influenzae was most common in the diseased adenoids, 53% in obstructive adenoid hyperplasia and 48% in chronic adenoid infection, compared with only 19% in the controls (P < .05). No significant differences in lymphocyte density, B and T cells, as well as T-helper subsets, were found between clinical classifications. However, T-suppressor cells, monocytes-macrophages, and natural killer cells were significantly increased in chronic adenoid infection only (P < .05). The findings in this study support roles for both alterations in bacterial homeostasis and an altered immune profile in the etiology of chronic adenoid disease in children.