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T Kocher

Publications and source records attributed to T Kocher.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Mesh-plug operation: a simple, rapid and complication-free technique for managing inguinal hernia].

INTRODUCTION: The optimal inguinal hernia repair technique is a matter of debate. The Shouldice operation has long been regarded as the gold standard. While specialized hernia clinics have reproduced good results, a recurrence rate for trainees and non-specialized surgeons of between 10% and 15% seems to be more common. Laparoscopic hernia surgery has brought decreasing postoperative morbidity, low post-operative disability and early return to work. These advantages of a tension-free technique are due to the use of a prosthetic mesh. It is largely the efforts of Gilbert, Lichtenstein and Rutkow/Robbins which have popularized the use of prosthetic mesh by an open anterior approach in the USA. METHODS: Since January 1997 we have prospectively evaluated the open mesh plug repair described by Rutkow/Robbins in Basel and Lugano. We have operated on 110 patients (103 male, 7 female). All patients were interviewed 4 weeks postoperatively at our clinic. RESULTS: There were no major complications. Two patients underwent reoperation for drainage of a haematoma. There was no early recurrence or infection. After 4 weeks 82% of all patients were back to normal activity. An early return to work has been noted (10 days on average for sedentary workers). CONCLUSION: The main advantages of this technique are simplicity, low cost, reduced post-operative disability and early return to work. It is much too early to say anything concerning recurrence in this series.

Adult↗
PubMed1998

C-type lectin-like receptors in peptide-specific HLA class I-restricted cytotoxic T lymphocytes: differential expression and modulation of effector functions in clones sharing identical TCR structure and epitope specificity.

C-type lectin-like inhibitory receptors are heterodimers consisting of CD94 and NKG2-A-B molecules expressed on NK cells and on a subset of activated T lymphocytes. Their inhibitory effects on NK cytotoxicity and on the NK-like activity of T cell clones have been demonstrated, but no data are currently available on antigen-specific class I-restricted cytotoxic T lymphocytes (CTL). We have generated a panel of HLA-A2.1-restricted CTL clones directed against a nonapeptide derived from a melanoma-associated antigen, dopachrome tautomerase (TRP-2). All clones were CD8+ and TCR alphabeta+. About half of them expressed a CD94bright phenotype, whereas the remaining were CD94dim. Only the CD94bright CTL expressed the NKG2-A-B gene, consistent with the expression of a C-type, lectin-like, inhibitory CD94/NKG2-A-B heterodimer. Both CD94bright and CD94dim clones appeared to require similar amounts of synthetic epitope sensitizing target cells. Addition of anti-CD94 mAb resulted in a significant increase of specific killing by CD94bright, but not by CD94dim clones in the presence of suboptimal concentrations of peptide, whereas, when optimal amounts were used, the mAb did not induce a significant modulation of the cytotoxicity. Antigen-induced inward [Ca2+]i fluxes were unaffected, but an enhancement of TCR down-modulation could be observed in the presence of anti-CD94 mAb at high concentration of antigenic peptide. The analysis of the TCR-Vbeta repertoire of the CTL clones by RT-PCR and immunofluorescence revealed that all clones regardless of CD94 phenotype shared Vbeta22 expression. Most importantly, sequence analysis showed that they all expressed identical Vbeta22 TCR rearranged with Jbeta2.1 and Cbeta2. Taken together, these data indicate that different expression of functionally active lectin-like inhibitory receptors can be detected in CTL clones sharing identical TCR sequence and peptide specificity.

Amino Acid Sequence↗
PubMed1998

Endoscopic surgery to the axilla--a substitute for conventional axillary clearance?

Nonpalpable, mammographically detected breast cancers are on the increase. The percentage of patients with histologically involved nodes is therefore decreasing. Axillary clearance aims at reducing the probability of later clinical involvement of the axilla and at establishing a sound basis for adjuvant treatment planning. Minimally invasive techniques have been applied to a growing number of surgical procedures now including exploration of the axilla. The technique used and results achieved in a series of 50 consecutive patients treated by liposuction and axilloscopy by one single surgeon, including all the patients from the very first attempt, are presented here. Patients were excluded with palpable lymph nodes or a primary tumor in the direct vicinity of the axilla that could be injured by the liposuction canula. The average number of lymph nodes removed was 13.4. Thirty-four percent of patients had involved nodes. The mean number of involved nodes in these patients was 3.1. After a median follow-up time of only 15 months no axillary recurrences or trocar site metastases have been found in the first 40 patients. Using a self-assessment questionnaire, the patients rate this technique as excellent. There was no lymphedema. The cosmetic result is certainly better than after conventional axillary clearance. Great experience of laparoscopic surgery and an excellent knowledge of the axillary anatomy are prerequisites for the practice of axilloscopic treatment of the axilla. The working space within the axilla is small and a number of structures need absolutely to be preserved. A longer follow-up period than the one so far achieved in this series or any other in the literature to date is necessary before this technique can be generally recommended.

Axilla↗
PubMed1998

Instrumentation of furcation with modified sonic scaler inserts: study on manikins, part I.

The purpose of this study was to determine the suitability of different scaling instruments for the debridement of furcations. 12 upper and 12 lower replicated molars with through-and-through furcations were instrumented 3x with 5 different types of instruments: (i) hand instruments; (ii) hand instruments in conjunction with diamond burrs; (iii) a conventional ultrasonic scaler insert; (iv) a conventional sonic scaler insert; (v) a set of 2 modified diamond coated sonic scaler inserts with different angulated shafts. The plastic replicas were fixed in a manikin head without replicated soft tissues. Following debridement, weight loss and % of instrumented furcation area were assessed. In the case of lower molars, it made little difference whether they were treated with hand instruments, hand instruments combined with diamond burrs, or diamond-coated sonic scaler inserts. On upper molars, however, significantly more area was instrumented with the diamond-coated inserts than with the other instruments. Substance removal was greater with diamond-coated inserts than with the other devices. In conclusion, an effective debridement of the furcation seems possible only with an odontoplasty, in which a furcation is fitted to the instrument by means of intensive instrumentation, thus leading to substance loss. To improve results with these instruments, further research is necessary.

Acrylic Resins↗
PubMed1998

Instrumentation of furcation with modified sonic scaler inserts: a study on manikins (II).

We developed a sonic scaler tip with an ellipsoid diamond-coated bud and contra-angulated shafts to overcome problems resulting from furcation anatomy. In this study, extracted molars were instrumented in a dummy model without any replicated soft tissues using 3 different instrumentation methods (i) curettes, (ii) diamond-coated sonic scaler tips with normal handle and (iii) diamond-coated sonic scaler tips in 2 handles with varying power levels. 15 extracted upper and lower molars were instrumented using each of the 3 instrumentation types. Following debridement, loss of substance and % of furcation area instrumented were assessed. In both upper and lower molars, significantly more surface area was instrumented in one instrumentation run with diamond-coated tips than with curettes. Substance loss was greater with diamond-coated tips than with hand instruments. In conclusion, an effective debridement of the furcation roof seems only possible with odontoplasty. Clinical evaluation of this approach to root debridement is needed.

Curettage↗
PubMed1998

[Endoscopic axilla dissection in invasive breast carcinoma. Initial experiences with a new technique].

The presence or absence of involved axillary lymph nodes is the single best predictor of survival of breast cancer, and important treatment decisions are based on it. For staging purpose as well as for local control a level I and II dissection is recommended. In order to lower the morbidity of axillary lymph node dissection less invasive treatment modalities have been evaluated. Beside the sentinel lymph node biopsy another new method is discussed: the endoscopic axillary lymph node dissection. After liposuction of the axillary fat the lymph nodes of level I and II are removed by endoscopy. With this technique enough lymph node can be removed which allows a sufficient staging as well as local control. This technique is not to be recommended for general use unless long term results have proven its value.

Axilla↗
PubMed1997

Effectiveness of subgingival instrumentation with power-driven instruments in the hands of experienced and inexperienced operators. A study on manikins.

Power instrumentation of periodontally-diseased root surfaces is gaining in significance as an alternative to conventional curette methods. In an experimental study employing manikins with simulated bone loss, we investigated whether inexperienced and experienced operators were able to achieve greater therapeutic success with power-driven devices than with hand instruments in subgingival scaling. 10 dentists experienced in periodontal treatment and 10 inexperienced dentists instrumented 7 teeth in the upper jaw, which had been covered with artificial deposits. Hand instruments, the Perioplaner system, a sonic and an ultrasonic scaler were used. The time required for treatment was measured and the % of residual deposits was calculated by means of image-processing techniques. Weight loss was also determined for the teeth that were scaled with the hand instruments and the Perioplaner system. Experienced operators left significantly less % of residual deposits on the teeth (18+/-7.6%) than the inexperienced (27+/-8.4%), regardless of the type of instrument selected. Both experienced and inexperienced operators left the smallest amounts of residual deposits with hand instruments (13+/-9.8%/24+/-9.5%). Both treatment groups removed more hard tooth structure with hand instruments than with the Perioplaner system (53+/-48mg versus 47+/-25.9 mg). Experienced operators needed somewhat more time for debridement than unexperienced. Use of the sonic/ultrasonic device required somewhat less time than hand instrumentation. Inexperienced operators are, however, unable to improve their treatment results by using the power-driven instruments included in the study.

Analysis of Variance↗
PubMed1997

Heterogeneity of melanoma antigen-1 (MAGE-1) gene and protein expression in malignant melanoma.

OBJECTIVE: The authors' objective is to identify MAGE-1 tumor antigen in clinical melanoma specimens and to verify the extent of its expression in tumors where evidence of specific gene transcripts can be obtained. BACKGROUND DATA: The MAGE-1 gene encodes a tumor-associated antigen that can be recognized by specific cytotoxic T lymphocytes. Transcription of the MAGE-1 gene has previously been demonstrated in various malignancies, but the production of the specific gene product and its distribution in neoplastic tissues have not yet been addressed. METHODS: Total cellular mRNA was extracted from six melanoma biopsies, reverse-transcribed and tested in 25-45 cycles of reverse polymerase chain reaction (rtPCR) in the presence of primers' pairs specific for the beta-actin-positive control gene and for the MAGE-1-encoding gene. Concurrently, portions of these specimens were lysed and probed for MAGE-1 protein by immunoblotting. Additional material from the same biopsies was analyzed following immunohistological staining with MAGE-1-specific monoclonal antibodies. RESULTS: MAGE-1 gene transcription could be demonstrated following 25 cycles of rtPCR in one out of six biopsies and in three more following 35 cycles of rtPCR. 2/6 samples were negative even after 45 cycles of rtPCR. MAGE-1 protein production could be detected by immunoblotting in the lysates from biopsies showing evidence of specific gene transcription. Cells positive for MAGE-1 protein expression could be identified by immunohistochemistry on snap-frozen sections in three of the four tumors displaying specific transcripts. Distribution of positivity ranged between focal cellular areas and single positive cells in the different tumors. CONCLUSIONS: The MAGE-1 tumor antigen can be detected by specific monoclonal antibodies in clinical tumor specimens. The pattern of positivity observed in samples showing evidence of MAGE-1 gene expression suggests a relevant heterogeneity regarding MAGE-1 antigen production within individual tumor specimens.

Antibodies, Monoclonal↗
PubMed1997

[Minimal invasive surgery in breast carcinoma].

The presence or absence of involved axillary lymph nodes is the single best predictor of survival of breast cancer, and important treatment decisions are based on it. For staging purpose as well as for local control a level I and II dissection is recommended. In order to lower the morbidity of axillary lymph node dissection less invasive treatment modalities have been evaluated. Beside the sentinel lymph node biopsy another new method is discussed: the endoscopic axillary lymph node dissection. After liposuction of the axillary fat the lymph nodes of level I and II are removed by endoscopy. With this technique enough lymph node can be removed which allows a sufficient staging as well as local control. This technique is not to be recommended for general use unless long term results have proven its value.

Adult↗
PubMed1997

Debridement by operators with varying degrees of experience: a comparative study on manikins.

The treatment of periodontally diseased root surfaces with power-driven instruments is becoming increasingly important as an alternative to the use of hand instruments. Root surfaces of artificial teeth on a manikin were debrided under simulated flap operation conditions to determine if effectiveness was dependent on the instrument used (curettes or a modified sonic scaler tip) and/or the operator's degree of experience. Two quadrants were treated with each instrument. A morphometric evaluation followed. Debridement was faster with the diamond-coated sonic scaler tip than with hand instruments. With the sonic scaler, the time necessary for treatment was reduced by 30%. The experienced operators treated about 80% of the root surface, while the inexperienced operators treated only about 65%. Treatment quality depended on the operator and not on the instrument used.

Clinical Competence↗
PubMed1997

The diamond-coated sonic scaler tip. Part I: Oscillation pattern of different sonic scaler inserts.

The authors have developed a set of four modified sonic scaler inserts with variously shaped shafts and diamond-coated budded inserts. The inserts are specially designed for the furcation area since instruments used hitherto have not been successful in completely preventing slow continuous periodontal breakdown in multirooted teeth. To test their clinical effectiveness, the displacement amplitude of the different sonic scalers was measured under varying load applications. Each scaler insert generated different and characteristic displacement amplitudes from rest position. The conventional insert was continuously dampened under increasing load application, whereas the diamond-coated inserts showed only minor variations of oscillation pattern. In a clinical situation, both insert types should be used, with the least possible application load to maintain effectiveness and minimize removal of hard tissue.

Dental Scaling↗
PubMed1997

The diamond-coated sonic scaler tip. Part II: Loss of substance and alteration of root surface texture after different scaling modalities.

The authors have developed a set of four modified sonic scaler inserts with variously shaped shafts and diamond-coated budded inserts. The inserts are specially designed for the furcation area since instruments used hitherto have not been successful in completely preventing slow continuous periodontal breakdown in multirooted teeth. To improve understanding of their clinical effectiveness, instrumentation of dentin samples was done with a curette as well as conventional and modified sonic scaler inserts under standardized conditions. The results showed that significantly greater amounts of tooth substance were removed with the diamond-coated airscaler tips than with the conventional tip. The depth of substance removal was comparable to that obtained with hand instruments and increased with application force. Although differences in surface texture were found among the different modes of scaling, it remains to be determined whether they are of clinical significance.

Analysis of Variance↗
PubMed1996

Cytotoxic T-lymphocyte responses against mutated p21 ras peptides: an analysis of specific T-cell-receptor gene usage.

Generation of cytotoxic-T-lymphocyte (CTL) responses against mutated ras peptides from peripheral-blood mononuclear cells (PBMC) was attempted in a group of HLA-A2.1+ healthy donors. Bulk PBMC cultures were stimulated in vitro with a mixture of peptides encompassing 12 Gly --> Val, 61 Gln --> Lys or 61 Gln --> Leu ras mutations and displaying HLA-A2.1 binding motifs, selected by a computer program. A promiscuous tetanus toxoid peptide was also added. Weekly thereafter, PBMC were re-stimulated with peptide pulsed autologous Epstein-Barr virus (EBV)-transformed B cells. After 8 rounds of re-stimulation, reproducible cytotoxic activity against peptide-pulsed target cells was detectable in one donor. The CTL line recognized 2 nonamers encompassing ras 61 Gln --> Leu mutation. Killing was mediated by CD8+ T cells displaying alphabeta TCR and was inhibited by anti-HLA-A2.1 monoclonal antibodies. No killing of tumor cells expressing the specific mutation could be observed. More than 60 CTL clones were generated. Fine specificity studies revealed effective, though differing cytotoxic activity against both 53-LDILDTAGL-61 and 55-ILDTAGLEE-63, but not against 54-DILDTAGLE-62 mutated peptides, in all but one of the clones. None was able to exert effective cytotoxic activity against tumor cells expressing the specific mutation. T-cell-receptor (TCR) usage was then analyzed phenotypically, by reverse-transcription-polymerase-chain-reaction (RT-PCR) and by sequence analysis. This study revealed the monoclonal nature of the CTL response against mutated nonamers, with TCR expressing Vbeta14 gene product in combination with, Jbeta2.7 and Cbeta2.

Amino Acid Sequence↗
PubMed1996

The tumour-associated antigen MAGE-1 is detectable in formalin-fixed paraffin sections of malignant melanoma.

The MAGE-1 gene encodes a protein encompassing a HLA-A1-restricted target epitope for cytolytic T lymphocytes. Monoclonal antibodies directed against the MAGE-1 protein were tested for usage in immunohistology of routine pathology material. Seven formalin-fixed, paraffin-embedded malignant melanomas were studied by the Avidin-Biotin complex (ABC) method with or without different antigen retrieval methods. Native, frozen tissues from the same tumours were used to validate the results by immunohistochemistry on frozen sections, by PCR for mRNA and by protein demonstration in tissue extracts using western blotting. Of 4 monoclonal antibodies tested, mAB 34B and mAB 77B were highly efficient in detecting MAGE-1 protein in deparaffinised sections with the regular ABC method after microwave pretreatment. In a series of an additional 28 patients 75% expressed MAGE-1, 50% in a substantial proportion. Follow-up studies in 6 patients indicate that the expression pattern remains stable but may change substantially within a short range. Immunohistology is thus a rapid and well-established method that might be used to select and monitor HLA-A1 positive patients with malignant melanoma and other candidate tumours for MAGE-1-directed immuno-therapy.

Antigens, Neoplasm↗
PubMed1996

[Surgery of inguinal hernia in Switzerland in 1994. A survey of 142 teaching clinics in Switzerland].

With a response rate of 60.6% to a questionnaire sent out in 1994 it is possible to give an overview of the situation in hernia surgery at the 142 surgical clinics of Switzerland. In general, regional anesthesia is the preferred method (67.4%). Together, Shouldice repair and fascia transversalis repair cover over 90% of the repair techniques in primary hernias. In recurrent hernias the same techniques dominate (70.2%) a large spectrum of different operation methods; implantation of foreign materials is rare (5.9%). Only 4.5% of all Swiss surgical clinics have some experience with endoscopic hernia surgery.

Endoscopy↗
PubMed1996

Proof of efficacy of different modified sonic scaler inserts used for debridement in furcations--a dummy head trial.

The purpose of this study was to determine the suitability of different scaling instruments for surgical removal of hard and soft bacterial deposits and for the removal of soft accretions only for maintenance treatment within furcations. 12 upper and 12 lower plastic replicated molars, with through-and-through furcations, were instrumented 3 x with 4 different types of instruments: (1) hand instruments; (2) a conventional sonic scaler insert; (3) a set of 3 modified sonic scaler inserts with budded tips and different angulated shafts; (4) a set of 3 sonic scaler inserts with a plastic-coating and different angulated shafts. The plastic replicas were fixed in a dummy head without any replicated soft tissues. In the furcation area, an easily removable surface coating material was applied to the teeth to represent the "plaque" and a second, more stubborn lacquer layer representing "calculus/cementum". Following instrumentation, the following parameters were recorded to assess efficacy; time required for instrumentation, loss of weight, depth of substance removal at the furcation entrance, % of furcation area instrumented, whereby removal of these 2 layers was judged separately. Only minor differences were observed between hand instruments, conventional and budded sonic scaler inserts as to loss of weight, depth of substance loss and area instrumented. The plastic-coated sonic scaler inserts were just as effective in surface layer removal representing "plaque" as the 3 other instruments, but resulted in less loss of weight and less depth of substance removal. In conclusion, the more aggressive hand instruments, the conventional and budded sonic scaler insert, are preferably used for the surgical phase to increased ease of entry into the furcation dome. An effective debridement of the furcation roof seems only possible with an odontoplastic, for which a furcation is fitted to the instrument by means of an intensive instrumentation, thus leading to weight loss and pronounced substance removal. The plastic-coated sonic scaler inserts seems to be a reasonable choice for maintenance treatment within furcation, since this treatment phase is usually restricted to removal of soft bacterial deposits.

Analysis of Variance↗
PubMed1996

Heat propagation in dentin during instrumentation with different sonic scaler tips.

It is important to know how much heat is generated when a root surface is debrided with sonic scalers and if that heat can be released satisfactorily into the environment. The temperature changes that occurred in dentinal specimens treated with two different sonic scaler tips, used with and without coolant, were studied. Temperature increases of up to 4 degrees C were observed for both tips when a coolant was used. Heat propagation during instrumentation was dependent to a considerable degree on the temperature of the coolant. Sonic scalers should not be used without coolant, because the dentinal temperature may increase up to 35 degrees C, depending on the force of application. A high positive linear correlation was found between increase in temperature and force of application.

Dental High-Speed Equipment↗