Biomedical subjects

R J Koch

Publications and source records attributed to R J Koch.

46 records · Page 3Linked to original sources

PubMed1993

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.

Cell Division↗

PubMed1992

Anatomic correlates of normal and diseased adenoids in children.

In order to better understand the pathogenesis and sequelae of obstructive adenoid hyperplasia in children, the anatomic relationships of the adenoids to the hard and soft palates, oropharynx, and nasopharynx were studied in vivo in 94 children. Direct, intraoperative palatal, nasopharyngeal, and oropharyngeal measurements were performed in 19 children with normal, nondiseased adenoids (controls [C]) and compared to 75 children undergoing adenoidectomy for obstructive adenoid hyperplasia (OAH) (n = 44) or chronic adenoid infection (CAI) (n = 31). As expected, the weight and volume of the adenoids removed were significantly greater in the OAH vs. CAI group (P < .001). Before adenoidectomy, the volume of the nasopharynx was significantly smaller in the OAH group; however, nasopharyngeal volumes after adenoidectomy were quite similar in all three groups and ranged from 5.4 to 6.2 cc. Only the change in the volume of the nasopharynx after adenoidectomy for obstruction was significant (2.5 +/- 1.2 cc, P < .01). Differences in oropharyngeal and palatal dimensions were not associated with longstanding obstruction from adenoid hyperplasia. These data indicate that the nasal obstruction from adenoid hyperplasia is due to an absolute increase in adenoid size rather than a relatively smaller nasopharynx. Differences in palatal and oropharyngeal dimensions usually described and attributed to longstanding nasal obstruction could not be demonstrated in this study.

Adenoidectomy↗

PubMed1991

Interleukin-6 production by murine B cells and B cell lines.

We have analyzed interleukin (IL)-6 gene transcription and IL-6 secretion by murine B cells in vitro. Mitogenic doses of lipopolysaccharide (LPS) or LPS in combination with F(ab')2 goat anti-mouse IgM antibodies (GAMmu), but not GAMmu alone, induced B cells to synthesize and release IL-6. In time course experiments, the accumulation of IL-6 mRNA was first detectable at 24-36 hr of culture and the levels were maintained through 60 hr; these kinetics correlated well with increases in supernatant IL-6 levels and were coincident with vigorous cell cycle activity. We also analyzed constitutive and LPS-induced IL-6 gene expression by the murine B cell lines: 70Z/3, 38C-13, WEHI-231, X16C, WEHI-279, and BCL1. Only the WEHI-279 and BCL1 lines produced detectable IL-6 constitutively, and the BCL1 cells could be further induced by treatment with LPS. Of the remaining cell lines, only WEHI-231 and X16C could be stimulated with LPS to produce IL-6. To evaluate whether IL-6 could influence proliferation and Ig secretion by the cell lines, low cell density cultures were established in the presence of various doses of human rIL-6 and were assessed over time for levels of [3H]thymidine uptake and supernatant Ig. Under these conditions, IL-6 had no effect on either cell function.

Animals↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Blepharoplasty↗

PubMedDate not supplied

Effect of tamoxifen on transforming growth factor beta1 production 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.

Cell Division↗

PubMedDate not supplied

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.

Carbon Dioxide↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

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.

Cells, Cultured↗