Biomedical subjects

W Wagner

Publications and source records attributed to W Wagner.

At least 73 records · Page 4Linked to original sources

PubMed2000

[Neuro-navigation in the central area: impact on different surgical steps related to the location and various pathological processes].

The neurosurgical treatment of space occupying processes in the central area bears a relatively high risk of either postoperative neurological deficits ("radical approach") or of residual tumor ("conservative approach"). Therefore, special techniques of intraoperative topographic orientation (image-guided surgery) play an important role here. The possible impact of neuronavigation on different neurosurgical steps (craniotomy, corticotomy, localization of the process, definition of borders of resection) was studied in relation to the site of pathology (extraaxial, intraaxial/superficial, intraaxial/deep) in 46 patients harbouring space occupying lesions of the central area. In intraaxial pathologies, additional electrophysiological monitoring was done. It could be shown, that in cases of deep seated processes, neuronavigation had the greatest impact on craniotomy, corticotomy and localization of the process, whereas the borders of resection were defined predominantly on the basis of differences in colour or consistency. In extraaxial pathologies, neuronavigation was of significance only for craniotomy; in intraaxial processes visible at the surface, it had an impact on craniotomy and--in a few cases--on definition of resection borders. In neurosurgery of intraaxial pathologies of the central area (particularly those not visible at the surface), the use of neuronavigation (or another method of intraoperative localization) in combination with neurophysiologic monitoring is strongly recommended.

Aged↗

PubMed2000

[Does ultrasonographic-morphologic staging of lymph nodes in head and neck cancer lend itself to automation?].

OBJECTIVES: B-scan ultrasound imaging is an obligatory examination of great clinical relevance in patients with head and neck cancer. The procedure, however, is dependent on an experienced examiner and thus requires higher personal resources than other examination techniques. In addition, its subjective character leads to possible deficits in reliability and objectivity. Established sonomorphologic criteria (echo-contour, echo-density, echo-structure, boundary) should therefore be matched to the findings of computer aided sonomorphometry. METHOD: 200 sonographic images of the cervical region of patients with oral carcinoma were analysed semi- and fully automatically as well as interactively by standard image analysis software (Quantimed 500, Leica, Germany). The results were evaluated statistically and correlated to the findings of both an experienced and inexperienced examiner. RESULTS: Fully automatic image analysis was impossible, as the software did not correctly identify the lymph nodes without interactive support. Quality of the semiautomatic and interactive image analysis mainly depended on the correct manual identification of the boundaries of the lymph node. Regarding this criterion the image analysis software was not able to compensate for the deficits of an inexperienced examiner. CONCLUSION: Delegation of the sonographic analysis to inexperienced, less qualified personnel, even with the help of image analysis software, seems to be inadvisable. This is especially the case if three-dimensional information from the real time analysis is not available.

Automation↗

PubMed2000

Cranial neuronavigation in neurosurgery: assessment of usefulness in relation to type and site of pathology in 284 patients.

OBJECTIVE: Neuronavigation improves intraoperative topographical orientation in neurosurgery. We wanted to better define the practical value of this technique in relation to the pathology operated on and the types of cranial surgery that profit the most from it. METHODS: Usefulness, interactive use and probably preventive effect of neuronavigation in cranial neurosurgery were assessed in a consecutive series of 284 patients on the basis of questionnaires with two- or five-point scale ratings by different neurosurgeons. RESULTS: Neuronavigation was most helpful in tumors of the hemispheres (particularly the central area) not visible at the cortical surface or resembling normal white matter, and in endoscopic procedures within small ventricles or cysts with non-translucent walls or when vision was blurred by cloudy CSF. In the same pathologies and surgical procedures, the device was interactively used, taking advantage of the specific possibilities of interactive image-guided neurosurgery. A probably preventive effect of neuronavigation was noted in operations in eloquent areas; highest scores were given for intraaxial tumors of the central region. The subjective assessments of usefulness, interactive use or preventive effect were not dependent on the involvement of the neurosurgeons in this study. CONCLUSION: We recommend this technique in resecting tumors in eloquent areas of the cortex or white matter, in approaching deep-seated processes not visible at the cortical surface, in defining borders of tumors resembling normal brain tissue, and in guiding endoscopes where ventricles are small or vision is blurred. This recommendation applies to any neurosurgeon familiar with the technique and managing neurosurgical cases requiring precise topographical orientation where normal anatomic landmarks are missing.

Adolescent↗

PubMed2000

Results of prophylactic irradiation in patients with resected keloids--a retrospective analysis.

The data of 139 patients with 166 keloids treated postoperatively between 1962 and 1996 were evaluated for prognostic factors and outcomes. Treatment commenced within 48 h after surgery. Radiotherapy was carried out as brachytherapy, using an integrated radionuclide 90 Sr-90Y surface applicator. The median dose delivered to the subcutis amounted to 14 Gy (range 7.5-28.5 Gy). The overall recurrence-free response rate was calculated to be 80% for all keloids. Response rates differed significantly (p < 0.001) between the different anatomical regions. The recurrence rate was lowest (2%) with keloids of the face and neck and highest with keloids of the thorax (49%). Outcome also differed significantly, depending on the etiology. Keloids following burns had a poorer success rate than those developing after surgery or mechanical trauma (p < 0.001). We were unable to demonstrate any significance in outcome related to gender, age or size. No direct correlation was found between total doses and response rates. In our patients there were no signs of secondary malignancies in the irradiation area within a median follow-up period of 12 years. Two new prognostic factors have been identified: keloid etiology and localization of the disorder.

Adult↗

PubMed2000

A pilot study of penicillin skin testing in patients with a history of penicillin allergy admitted to a medical ICU.

BACKGROUND: Penicillin skin testing is an accurate method to determine whether a person with a history of penicillin allergy is at risk of having an immediate reaction to penicillin. A patient with a negative reaction to a skin test may be able to use a penicillin compound safely, which could reduce the use of broad-spectrum antibiotics in this patient population. METHODS: We prospectively studied all patients with histories of penicillin allergy who were admitted to a medical ICU during a 3-month period and who received antibiotics. Skin testing was performed with benzylpenicilloyl polylysine and penicillin G. We determined the incidence of true allergy, the percentage of patients in whom antibiotic coverage was modified, and the safety of the test. RESULTS: Two hundred fifty-seven patients were admitted to the medical ICU of The Cleveland Clinic Foundation during the study period. Twenty-four patients (9%), labeled as penicillin allergic and receiving antibiotics, were enrolled. Three patients (13%, 3 of 21) gave histories of type I reaction to penicillin and were not skin tested. Twenty patients (95%, 20 of 21) had negative skin test reactions to penicillin and positive skin test reactions to histamine control. One patient (4%, 1 of 21) with negative skin test reactions to both penicillin and histamine control had a test dose challenge with piperacillin that was well tolerated. There were no adverse events. Antibiotic coverage was changed in 10 patients (48%) as a result of skin testing. CONCLUSION: Most patients with histories of allergy to penicillin have negative reactions to skin tests and may receive penicillin safely. Penicillin skin testing can be utilized as a safe and effective strategy to reduce the use of broad-spectrum antibiotics.

Adult↗

PubMed1999

Results of fast neutron therapy of adenoid cystic carcinoma of the salivary glands.

INTRODUCTION: Patients with adenoid cystic carcinoma (ACC) of the salivary glands in the head and neck region have been reported to benefit from neutron radiotherapy according to significant clinical experience. A prospective clinical trial on the efficacy and treatment related morbidity of fast neutron radiotherapy was performed between 1986 and 1995 at the (d + T) 14 MeV neutron generator in Münster. MATERIAL AND METHODS: 72 consecutive patients with ACC were treated with fast neutrons, 66 after surgery, 6 for primarily unresectable disease, 43/66 for macroscopic residual disease, 23/66 for unresectable recurrent disease. 45/72 tumors were localized in the minor, 27 in the major salivary glands. T-stage was in 13 pts T2, in 33 T3, in 26 T4; positive nodes were in 10 pts, M+ in 15 pts. Mean tumor volume was 89 cm3. Neutron therapy was 15.03 Gy in 3 weeks with 1.67 Gy per fraction three times per week. Individual computer assisted treatment planning was performed based on CT and/or MRI, using bolus material if necessary. Target volume was the macroscopic tumor volume with a generous safety margin. RESULTS: Complete response was achieved in 28 pts, partial response in 35 pts. Local control was observed in 73.4% after a mean observation period of 36 months. Overall and recurrence free survival was 85%/81% at two years, and 58%/53% at 5 years (Kaplan-Meier). In univariate analysis tumor volume (> 100 cm3), distant metastases, histologic subtype (solid) and neutron dose (< 15 Gy) turned out to be significant parameters for predicting outcome, in multivariate analysis tumor volume and histologic subtype remained the only significant parameters. Acute morbidity was grade III/IV (EORTC/RTOG) in 6% for skin (desquamation), in 4% for mucosa (ulceration), late morbidity (grade III/IV) in one patient with local temporal brain necrosis. CONCLUSION: According to this experience and taking into account the so far collected experience, fast neutron radio-therapy remains the treatment of choice for large and unresectable primary and recurrent ACC, and residual disease after surgery.

Adolescent↗

PubMed1999

[Prognosis and prognostic factors of endosseous implants in the irradiated jaw].

In comparison to tumor patients not receiving radiotherapy, the rehabilitation of masticatory function after head and neck irradiation is limited due to radiation-induced caries, radioxerostomia, and the risk of osteoradionecrosis. This study focused on implants in the irradiated jaw and on the evaluation of the prognosis and the effect of potential factors on the prognosis. The retrospective study covered 197 implants (47 patients) from 1988 to 1997. The implant prognosis was determined by implant survival statistics (Kaplan-Meier). Losses not related to the implants were censored. In addition, groups were formed according to factors potentially affecting the prognosis. The significance of differences in the groups relative to survival were tested using the log-rank test. Twelve (6.1%) implants from a total of 197 were lost due to peri-implantitis, and eight (4.1%) due to possible biomechanical stress. A total of 52 losses (26.4%) due to death of patients and two (1.0%) due to resection of the jaw were censored; 111 (56.3%) implants remained at recall and the average interval was 33 months. The rates of implant survival (Kaplan-Meier) after 1 and 2 years were 95%, after 3 and 4 years 92%, and after 5 and 6 years 72%. The univariate analysis of group comparisons showed a significantly lower rate of loss after perimplant flap reconstruction (p = 0.036). There was no effect due to the doses of irradiation (p = 0.16), chemotherapy (p = 0.90), or peri-implant osteoplasty (p = 0.84). Although none of the implants inserted before radiotherapy had to be explanted, the implant survival difference in the very heterogeneous groups was not significant (preirradiation, n = 29; postirradiation: n = 156; p = 0.13). According to the literature, the rate of survival of teeth which were sound before radiotherapy (1 year, 75%; 5 years, 45%) was distinctly lower than the survival of enossal implants (1 year, 95%; 5 years, 72%). The high-quality rehabilitation of masticatory function with implant-based protheses is the preferred method of treatment for irradiated tumor patients. In addition, contraindications for enossal implants were ruled out for all studied factors affecting prognosis.

Adult↗

PubMed1999

[Comparative studies of Brånemark implants in the irradiated and not irradiated mandible].

A comparative study was carried out of 276 Brånemark fixtures in the irradiated and nonirradiated anterior mandible with a mean follow-up period of 58.2 months. Postoperative radiotherapy with 60 Gy and 100% isodose for the anterior mandible using a 6-MV linear accelerator, conventional fractioning, and a split-course technique was administered in the irradiated patient group. HBO therapy was not applied. A statistical difference in the 5-year success rate between the irradiated and nonirradiated group was not found. Nevertheless, a significantly higher rate of perioperative soft tissue complications at implant insertion was seen in the irradiated group. The statistical analysis showed no significance for sex, interval between radiation and implant insertion (with a minimum of 10 months), or type of periimplant soft tissue (regional vs. flap). The prognosis for implants in the irradiated mandible was, however, statistically improved (n = 0.0035) when the healing period was longer than 4 months. Mobile periimplant soft tissue proved to be the main problem regardless of radiation load. Late complications have not been observed so far. The available results and clinical studies support a positive assessment of the regenerative potential of the irradiated mandible with regard to osteointegration of endosseous implants. A preceding radiotherapy up to 60 Gy should therefore not be considered as a contraindication for an implant/prosthetic rehabilitation.

Adult↗

PubMed1999

[The maxilla--a poor implant site?].

In the maxilla, it is sometimes necessary to use implants to achieve a good prosthetic result. However, an increased failure rate of maxillary implants seems to be a common clinical experience. This experience was investigated in a retrospective statistical analysis. In a retrospective study of 665 patients between 1987 and 1997, 2484 implants were examined. The implants in the upper jaw were compared to those in the lower jaw. Implants with and without autogenous bone grafts and fixtures in patients with alveolar ridge atrophy, tumor, or trauma were explored. In particular, the data obtained from the orthopantomograms after completion of the prosthetic superstructures were controlled for peri-implantary bone loss evaluation. A total of 40% of the fixtures were placed in the maxilla, and 30% of these implants were combined with a local or an iliac bone graft. Out of 2484 implants, 207 were lost, largely during the healing period. The failure rates in the groups of patients with alveolar ridge atrophy, tumor, and trauma were between 6 and 27.5%, and the differences between these groups were higher than the difference between the upper and the lower jaw. Especially in the maxilla and after osteoplasty, horizontal peri-implantary bone loss was increased, with some cases of dramatic bone loss and decrease of the osseous integration of the fixtures. There was no statistic evidence of a significantly higher failure rate in the upper jaw than in the lower jaw. However, besides the rate of implant loss, additional markers should also be considered for adequate evaluation of implant prognosis in the maxilla.

Alveolar Bone Loss↗

PubMed1999

[Prospective double-blind study of prophylaxis of radioxerostomia with Coumarin/Troxerutine in patients with head and neck cancer].

AIM: Prospective, randomized placebo-controlled double-blind study to prove the efficacy of Coumarin/Troxerutine (Venalot Depot) for protection of salivary glands during a head and neck irradiation. PATIENTS AND METHOD: Forty-eight radiotherapy patients (60 Gy) with head and neck cancer were included in this trial. During radiotherapy the salivary glands were located in the core irradiation field. Primary efficacy parameters were sialometry, quantitative salivary gland scintigraphy and clinical evaluation of early effects of radiotherapy (RTOG-score, Table 1). All data were collected at 6 assessments: 1 week pre-radiation (U1), at start (U2), half time (U3) and end (U4) of irradiation, 8 days (U5) and 28 days (U6) after the end of irradiation (Figure 1). RESULTS: Twenty-three patients (11 verum, 12 placebo) completed the study with all assessments. Sialometrically, all patients were severely (half of radiotherapy) or completely (end of radiotherapy) xerostomatic (Figure 2). In a global efficacy measure according to O'Brien combining scintigraphy and RTOG there was a tendency for a higher efficacy of verum compared to placebo (p = 0.068). After start of irradiation therapy, the RTOG-score showed continuously and significantly lower early radiation effects under verum than under placebo (U3 vs U6: p < 0.05, area under curve: p = 0.032; Table 2, Figure 3). The scintigraphically determined excretion fraction was slightly less impaired in the verum group compared to the placebo treatment (p = 0.12. Figure 4). There was no difference in drug safety between placebo and verum for adverse events, changes in the activity of liver enzymes and for global impression of tolerability. CONCLUSIONS: The results give support for an advantageous effect of Venalot Depot in the treatment of radiogenic sialadenitis and mucositis. In even a small number of evaluable patients, early clinical effects of irradiation (RTOG-score) were less pronounced in the active treatment group than in the placebo group, but the sample size was too low to prove statistically also the benefit of coumarin/troxerutine with the scintigraphic method. Sialometry seems not suitable for the assessment of early radiation effects.

Adult↗

PubMed1999

Confocal laser scanning microscopy: A nondestructive subsurface histotomography of healthy human bone.

Microscopy of bony tissue usually requires special treatment for decalcification and processing of thin sections. Confocal laser scanning microscopy (CLSM) allows the nondestructive histotomography of organic hard tissue. The aim of this study was to visualize healthy human bone structures and to correlate identical areas in CLSM and conventional light microscopy. Each sample of healthy human lower jaw (n = 20) was divided into three parts: (1) fresh, untreated bony blocks studied by CLSM; (2) MMA-embedded thin sections (without decalcification), HE stained and studied by CLSM and conventional light microscopy (correlation of identical areas); (3) decalcificated, HE stained, histological sections studied by conventional light microscopy. In untreated bony blocks, microstructures such as osteocytes and lamellae were identified by CLSM. These structures could be correlated with conventional light microscopy. In CLSM, subcellular structures cannot yet be interpreted, whereas cytoplastic processes of osteocytes were seen with high contrast. With CLSM, nondestructive histology of cortical bone can be obtained. The risk of artifacts due to pretreatment is minimized, and subsurface visualization does not affect the interpretation.

Histological Techniques↗

PubMed1999

Vulvar carcinoma: a retrospective analysis of 80 patients.

We evaluated the files of 80 women who were treated for vulvar carcinoma. In 13 women radiotherapy was used as primary treatment, in 45 cases postoperatively and in 22 women because of local recurrence. Patients older than 60 years had a significantly worse 5-year survival rate (39%) than younger women (57%) (p = 0.02). The 5-year survival rate for patients with negative nodes was 72% versus 46% for the N1- and 47% for the N2-status, respectively (p = 0.027). The 5-year actuarial survival rate for patients with tumor manifestation in the clitoris was 77.9% versus 26.1% for patients with tumors in the labia majora (p = 0.0044). There was no difference in survival in patients who had been treated with radical vulvectomy and bilateral groin dissection plus local radiotherapy when compared with patients who had been irradiated (whole pelvis) after tumor resection alone. The 5-year survival rates and the median survival time were identical in both groups (61%/62 months).

Adenocarcinoma↗

PubMed1999

The relationship between auditory threshold and evoked otoacoustic emissions.

The aim of this study was to compare transiently evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) in normal hearing ears (n = 44) and ears with cochlear hearing loss (HL) to obtain defined data on qualitative and quantitative correlations. In addition, we wanted to determine the reliability with which a clinical examiner could predict a typical, idealized audiometric configuration from TEOAE measurements. In the hearing-impaired subjects (n = 149), a 50% reduction of OAE incidence was caused by a mean HL of 10.5 dB for TEOAE compared to 27 dB SPL for DPOAE. A 90% incidence reduction was found at a mean threshold elevation of 33 dB for TEOAE and 51 dB for DPOAE. Correlation between TEOAE amplitudes and HL was in general rather low (r = -0.1 to -0.5), while DPOAE amplitudes showed a slightly better correlation with HL (r = -0.3 to -0.6). In general, efforts to derive an audiogram from evoked OAE have been more promising for DPOAE than for TEOAE. However, our studies showed that approximately 40% of the ears with HL could be categorized correctly into one of five typical audiometric patterns from TEOAE measurements. Additionally, a cochlear HL in or near the medium frequency range was much more likely to cause a reduction in TEOAE than an isolated low- or high-frequency lesion. Accordingly, TEOAE were often preserved in ears with isolated HL in the high or low frequencies.

Acoustic Stimulation↗

PubMed1999

[Changes in the nasal airway by transverse distraction of the maxilla].

OBJECTIVE: To investigate nasal airway changes through transverse maxillary distraction osteogenesis by means of an objective, reliable, noninvasive investigation technique with special attention to nasal valve changes and widening of the posterior maxilla. PATIENTS AND INTERVENTION: Eight patients with a severe maxillary transversal deficit underwent surgically assisted rapid palatal expansion in local or general anesthesia. Before and after the distraction process, a transnasal series of acoustic measurements of nasal airway profile was performed under topical decongestion. Nasal volume was calculated by integration of the area profile. The cross-sectional area of the nasal valve was also determined. RESULTS: A significant enlargement of nasal volume was recorded in all patients (P < 0.01: Wilcoxon signed rank test). The average increase measured 5 cm3 (23%). The increase in volume was recorded in all parts of the nasal cavity, indicating complete maxillary expansion even in the posterior segment. The nasal valve area raised from 0.56 to 0.70 cm2 (P < 0.01). Six out of eight patients reported striking improvement of nasal patency after maxillary distraction. CONCLUSION: Besides correction of the maxillary arch deformity, rapid palatal expansion contributes to improved nasal patency by resolving nasal valve constriction. Significant widening of the posterior nasal cavity was achieved, indicating a translational pattern of maxillary movement, although the pterygomaxillary junction was not touched in the osteotomy.

Adult↗

PubMed1999

[Roentgen spectrometry comparison of currently available bone substitutes].

INTRODUCTION: The crystalline structure of hydroxyapatite (HA) and tricalciumphosphate (TCP) used as bone regeneration materials affects their physical and probably also their biological properties. Varying velocities of the HA solution process seem to be correlated to different results in powder diffraction analysis (RDX) [1], a validated, routine procedure in minerology [2, 6] to analyse crystallized materials. As far we know there are no comparative RDX analyses for the TCP materials in clinical use. GOALS: The dimension and quality of the crystallization of several bone regeneration materials are analysed by RDX. MATERIAL AND METHODS: The materials analysed were divided in different groups: hydroxyapatite, tricalciumphosphate and bioglass. The materials are characterized by the specific intensity curve measurements. RESULTS: The HA products, with the exception of Algipore, seem to be monophasic. Ceros80 and Endobone were the only ones which seem to be totally crystallized. The TCP products Biobase and Cerasorb are nearly monophasic, whereas Ceros82 seems to contain a mixture of 30% HA and 70% beta-TCP. All TCPs show a high crystallization. The bioglasses did--as suspected--not show crystalline structures. DISCUSSION: There are many possible causes for inhomogeneous crystallization of the investigated materials, as they are composites of different foreign ions, extremely small crystals or abnormal (deficient) apatites. How this affects the biological behaviour is not known. SUMMARY: We found differences between the examined materials; how this affects the biological behaviour is unknown. Further investigations are necessary to correlate the characteristics of the materials to the clinical outcome.

Bone Substitutes↗

PubMed1999

[Micromorphological findings in jaw bone after radiotherapy. Confocal laser scanning microscopy and fluorescence darkfield microscopy studies].

Early radiation effects on human bone may lead to osteoradionecrosis (ORN). Direct bone cellular lesions [28] as well as fibrous degeneration of blood vessels [21] are considered to be pathologically relevant. Only few data on initial subclinical radiation effects are available. Patients were grouped according to the dose of radiation and clinical findings. Group 1: sound human bone of lower jaw, mostly collected during orthodontic surgery (n = 10 patients); group 2: specimens of lower jaw from patients with ORN (n = 12 patients); group 3: specimens of lower jaw from patients with head and neck cancer who were preoperatively treated with 36 Gy radiation; group 4: specimens of lower jaw from patients with head and neck cancer (n = 9) who were treated with 60-70 Gy radiation. Specimens were studied by confocal laser scanning microscopy (CLSM), by conventional light microscopy (DL) and by fluorescence darkfield microscopy (DFM) after bisbenzimide staining (H 33258) of the viable cellular nuclei. For the correlating study of identical areas in CLSM and DL the specimens were prepared according to the sawing and grinding technique [8]. All the radiated bony specimens, regardless of the dose of radiation, showed areas of extensive or total loss of vitality of the osteocytes. This finding was also evident after 36 Gy and a short interval between radiation and sample collection (group 3). Additionally, in CLSM micromorphologic lesions of the lamellate structure were seen. With these results we can confirm the loss of vitality of the osteocytes as an initial radiation effect as described earlier [10, 23, 28]. In addition to these findings, alteration of the lamellate microstructure was found in the early phase after radiation. The functional and mechanical significance of these findings should be the subject of further studies.

Bone and Bones↗

PubMed1999

[Tissue damage and regeneration after laser surgery using different scanning systems].

INTRODUCTION: Laser systems are frequently used in dentistry. New laser scanner technologies are promising more homogeneous ablation of pathological ablations of the skin and mucosa. The theoretical advantages of these systems have not yet been sufficiently evaluated by histological findings. For this reason, we compared two laser scanners with different scanning patterns in this study (Silktouch and Swiftlase, by Sharplan, Germany). MATERIALS AND METHODS: In this animal study (79 male Osborn-Mendel rats), skin defects of 3-mm diameter were lasered on to the backs of the animals, one for each method mentioned above (defocused laser, Swiftlase, and Silktouch). The histological investigations were conducted, depending on the time after surgery (9 h, 1, 2, 3, 4, 5, 6, 7, 9, 11, or 13 days). On the clinical site, we evaluated the visible ablation rate, homogeneity and morphology of the wound surface and the degree of carbonization. In the histomorphological investigations, we determined the degree of thermal damage as well as the morphology of the necrotic area and reepithelization pattern of the surface. RESULTS: The Silktouch scanner clinically showed a homogeneous ablation rate with less carbonization than the Swiftlase scanner. In the histological specimen, this correlated with an increase in the tissue ablation rate and decreasing thermal damage to the surrounding tissue. Especially in the early wound-healing period, there was a more rapid reepithelization after the use of the Silktouch scanner. These differences could not be evaluated in the later wound-healing period. Compared to the defocused laser ablation, both scanning systems seem to have benefits within these parameters. CONCLUSIONS: The results of this study seem to show a diminished perifocal damage and reduced clinical postoperative morbidity achieved by using laser scanning systems. Compared to the Swiftlase laser, the Silktouch seems to deliver better results.

Animals↗

PubMed1999

T cell immunosenescence in vitro and in vivo.

The term "immunosenescence" refers to an age-associated dysregulation of immune function which contributes to the increased susceptibility of the elderly to infectious disease. Although there are age-associated changes measurable in the innate immune system (Pawelec et al., 1998c), it is the adaptive, particularly T cell, system which is most susceptible to the deleterious effects of aging. In this minireview, characteristics of aging in long-term human T cell cultures will be summarized, and the parallels between the in vitro model and in vivo immunosenescence will be documented. The use of culture models to screen for ways of manipulating immunosenescence in vitro may provide a basis for intervention to ameliorate immunosenescence in vivo.

Aging↗