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Biomedical subjects

C Stock

Publications and source records attributed to C Stock.

At least 19 recordsLinked to original sources
PubMed1996

Isochromosome 12p and maternal loss of 1p36 in a pediatric testicular germ cell tumor.

Analysis of a pediatric germ cell tumor by conventional cytogenetic investigation and fluorescence in situ hybridization showed consistently the presence of two isochromosomes 12p, loss of the maternal band 1p36, and other numerical and structural chromosome changes. The rearrangements observed resulted mainly from breaks occurring at paracentromeric regions. This report represents the first description of i(12)(p10) in a pediatric testicular embryonal carcinoma.

Adolescent↗
PubMed1996

[Tumor cell dissemination in bone marrow and peritoneal cavity. An immunocytochemical study of patients with stomach or colorectal carcinoma].

The tumor spread and the radicality of surgical resection are the most important facts in a patient's prognosis. In spite of curative tumor resection many patients die from metastases or local tumor recurrence. One possible reason is early dissemination of tumor cells which cannot be detected with clinical methods of examination. For this reason the aim of our study was to examine both bone marrow and peritoneal lavage for disseminated tumor cells with an immunocytochemical technique in patients with a gastrointestinal carcinoma. We also wanted to find out whether there was any correlation between the incidence of tumor cell detection and the TNM classification, staging and tumor grading and whether disseminated tumor cells have any prognostic significance. Our study included 54 patients who underwent surgery in our clinic for a carcinoma of the stomach (20 patients) or the colorectum (34 patients) from November 1993 to December 1994. At the beginning of the operation bone marrow had been taken from the iliac spine, and the abdomen was irrigated with 1000 ml saline solution immediately after laparotomy or laparoscopy. After cell separation with Ficoll density centrifugation 5 x 10(5) cells were applied per slide by a cytospin technique. For detection of the tumor cells we used the APAAP technique and the following monoclonal antibodies: KL1, CK2, anti-CEA, 17-1A (bone marrow) and Ber-EP4, B72.3, anti-CEA and 17-1A (peritoneal lavage). Altogether 77% of all patients had tumor cells in the bone marrow and 69% in peritoneal lavage fluid. It was possible to detect tumor cells in bone marrow (67%) and peritoneal lavage fluid (25%) even of patients with T1 tumors. The percentage increased with depth of wall infiltration. There was a marked difference in bone marrow aspirates between patients with lymph-node-negative tumors (N0) and those with lymph-node-positive tumors (N+): 65% had tumor cells in N0 and 85% in N+ stages. This trend was also seen in patients with (M1) and without (M0) metastases, in both bone marrow aspirates and peritoneal lavage fluid. In bone marrow there was a good correlation of tumor cells with staging, but in peritoneal lavage fluid this was not so. Finally, we detected tumor cells more often in bone marrow and peritoneal lavage fluid of patients with poorly differentiated tumors (G3) or diffuse Lauren type than in patients with moderately differentiated tumors (G2) or intestinal Lauren type. After a median follow-up period of 12.5 months patients with disseminated tumor cells had a lower survival rate than patients without tumor cells.

Adult↗
PubMed1996

Electroencephalogram activity, catecholamines, and lymphocyte subpopulations after resistance exercise and during regeneration.

We examined the effect in ten male sports students of 30-min resistance exercise followed by either 45-min regeneration with massage treatment on a massage bench or supine rest serving as control, on plasma catecholamine concentration, number and distribution of circulating white blood cells and central activity. Resistance exercise increased free plasma adrenaline (A) and noradrenaline (NA), whereas sulphoconjugated catecholamine concentration remained unchanged as determined by high performance liquid chromatography. Exercise induced leucocytosis and lymphocytosis measured by flow cytometry was predominantly manifested by an increase in the number of lymphocytes, monocytes, CD3+ cells, CD8+ cells and CD3- CD16/56+ cells. Computer-aided electroencephalography (EEG) revealed significant increases in absolute EEG band power. The increase was highest in alpha 2 with 51.6 (SD 40.2)% (P < 0.01), followed by beta 1 with 33.3 (SD 21.0)% (P < 0.01), alpha 1 with 31.9 (SD 25.2)% (P < 0.01), beta 2 with 30.8 (SD 26.7)% (P < 0.01), delta with 26.1 (SD 28.7)% (P < 0.05), and theta with 19.8 (SD 16.5)% (P < 0.01). All hormone and immunological variables returned to pre-exercise values 45 min after exercise with no differences between massage and control treatments. However, during regeneration differences in absolute EEG-band power were observed between massage and control treatments. In central (Cz, C3, C4) and fronto-lateral (F3, F4) electrode positions absolute beta 1 spectral power density was significantly lower during massage treatment than during control (Wilcoxon test: P < 0.01). Overall, these data demonstrated that an influence of massage treatment on deactivation characteristics could be observed in EEG measurements but not in plasma catecholamine concentration or blood lymphocytes, indicating that computer-aided topographical EEG may be a useful technique for studying activation and regeneration characteristics.

Adult↗
PubMed1996

Laparoscopic retroperitoneal lymph node dissection for nonseminomatous germ cell tumors: indications and limitations.

PURPOSE: We describe our experience with laparoscopic retroperitoneal lymph node dissection in 26 patients with nonseminomatous germ cell tumors: 17 had stage I disease with no clinical (computerized tomography, ultrasound or tumor markers) evidence of metastases and 9 (2 with stage IIb and 7 with stage IIc disease) had residual tumor after chemotherapy but with negative tumor markers. Laparoscopic dissection was performed to assess more fully pathological status of the relevant retroperitoneal lymph nodes in both groups. MATERIALS AND METHODS: The patient was positioned and trocars were introduced at sites similar to that used for transperitoneal laparoscopic nephrectomy (flank position with 3, 10 mm. and 2, 5 mm. ports). After the white line of Toldt was incised and the colon was reflected anteromedially, the retroperitoneal space was exposed. The landmarks of lymph node dissection were then isolated, including the ureter, aorta, inferior vena cava and both renal veins. Lymph node dissection was performed identical to that for open surgery, with a modified template including the paracaval, interaortocaval, upper preaortic and right common iliac nodes for right tumors, and para-aortic and upper preaortic nodes for left tumors. Lymph node chains were retrieved with a small organ bag. RESULTS: The procedure was completed successfully in 16 of 17 patients with stage I disease (mean duration 268 minutes for the left and 312 minutes for the right sides). No intraoperative complications were encountered. One patient had delayed ureteral stenosis requiring operative repair, 1 had a pulmonary embolism with an uneventful outcome and 1 who underwent laparoscopic retroperitoneal lymph node dissection on the right side later had retrograde ejaculation. Embryonal carcinoma was found in 1 of the 17 patients. Average postoperative hospital stay was 4.5 days for patients without complications or conversion to an open procedure. After a median followup of 27 months no patient had regional relapse but 2 had pulmonary metastases that were treated successfully with 3 cycles of platinum based chemotherapy. Laparoscopic dissection was significantly more difficult in patients with stage II tumors after chemotherapy. Only in 2 patients with stage IIb disease was laparoscopic lymphadenectomy successful. In 5 of the 7 patients with stage IIc cancer portions of the dissection had to be done after conversion to an open (conventional) operation via a small incision (suprainguinal or pararectal). In 1 patient the laparoscopic approach was completely abandoned and converted to an open operation via a standard midline incision. In all 9 cases histopathological examination revealed complete necrosis. No patient has evidence of disease. CONCLUSIONS: Our preliminary experience suggests that a modified laparoscopic retroperitoneal lymph node dissection is feasible for stage I tumors. However, it cannot be recommended after previous chemotherapy (stages IIb and IIc disease).

Follow-Up Studies↗
PubMed1996

[Transperitoneal and retroperitoneal laparoscopic nephrectomy in comparison with conventional nephrectomy].

We report on our clinical experience with laparoscopic nephrectomy in 35 patients. We have performed a total of 18 transperitoneal laparoscopic nephrectomies (TLN) for benign renal disease. After the introduction of a hydraulic dissecting device, we have since performed 17 retroperitoneal laparoscopic nephrectomies (RLN). These data were compared with those in 19 consecutive open nephrectomies (N). All groups were comparable in terms of indication. The mean operative time for benign disease was 206.5 min for TLN, 211.2 min for RLN and 117 min for N. Analgesic medication requirement per patient was 2 days for TLN, 1 day for RLN and 4 days for N, while the postoperative hospital stay averaged 7 days for TLN, 6 days for RLN and 10 days for N. Our results demonstrate the advantage of a laparoscopic approach over open surgery and also reveal the distinct benefit of a retroperitoneal approach. However, due to the small number of indications this procedure should be restricted to a few urologic centers.

Humans↗
PubMed1996

Retroperitoneal laparoscopic lymph node dissection for staging non-seminomatous germ cell tumors before and after chemotherapy.

We describe our experience with laparoscopic retroperitoneal lymph node dissection in 19 patients with non-seminomatous germ cell tumors. Twelve patients had stage I disease with no clinical evidence (CT-scan, ultrasound, tumor markers) of metastases; 7 patients (stage IIb=2, stage IIc=5) had residual tumor after chemotherapy but with negative tumor markers. A laparoscopic dissection was used to asses more fully the pathologic status of the relevant retroperitoneal lymph nodes of both groups. The patient was positioned and trocars introduced at sites similar to that used for transperitoneal laparoscopic nephrectomy (flank position, five ports - 3 x 10 mm; 2 x 5 mm). After reflecting the colon anteromedially, the landmarks of the lymph node dissection were isolated-namely the ureter, aorta, inferior vena cava, and both renal veins. The lymph node dissection included the paracaval, interaorto-caval, upper preaortic, and right common iliac zonal nodes for right-sided tumors, and paraaortic, upper preaortic zones for left-sided tumors. Retrieval of the lymph nodal chains was accomplished using a small organ bag. The mean duration of the procedure was 298 (range 150-405) minutes. In only one patient was a lymph node positive for tumor (stage I). Otherwise nodes showed extensive necrosis (after chemotherapy). No intraoperative complications were encountered but three patients developed a delayed complication (ureteral stenosis, pulmonary embolism, and retrograde ejaculation, respectively). Whereas we completed the dissection in each patient with stage I tumors, the laparoscopic procedure was more difficult in patients with stage II tumors after chemotherapy. In two patients with stage IIb disease laparoscopic lymphadenectomy was successful. In four other patients parts of the dissection had to be done after conversion to an open (conventional) operation using a small incision (suprainguinal or pararectal); in one patient the laparoscopic approach was abandoned and converted to an open operation. In the post-chemotherapy group the outcome depended primarily on the tumor bulk prior to drug treatment. In two patients in whom all residual necrotic tissue was removed laparoscopically they had "minor" disease (stage IIb); the others had stage IIc tumors. Our preliminary experience suggests that a modified laparoscopic lymph node dissection is feasible for stage I tumors and in selected patients with marker negative residual tumor after chemotherapy (stage IIb).

Feasibility Studies↗
PubMed1995

Catecholamines, lymphocyte subsets, and cyclic adenosine monophosphate production in mononuclear cells and CD4+ cells in response to submaximal resistance exercise.

We examined the effect of 30 min of submaximal resistance exercise on free and sulphoconjugated plasma catecholamine concentrations determined by high performance (-pressure) liquid chromatography separation, the distribution of circulating lymphocytes quantified by flow cytometry, and isoproterenol induced cyclic adenosine monophosphate (cAMP) production in mononuclear cells (MNL) and CD4+ cells. Venous blood samples were taken before, immediately after and 45 min after exercise. Resistance exercise increased free plasma adrenaline (A) and noradrenaline (NA) concentrations, whereas sulphoconjugated catecholamine concentrations remained unchanged. Exercise induced leucocytosis and lymphocytosis was predominantly manifested by an increase in the number of total lymphocytes, monocytes, CD3+, CD8+ cells and CD3- CD16/CD56+ cells. Redistribution resulted in a decrease in the CD4+:CD8+ ratio. The total number and distribution of lymphocytes returned to baseline after 45-min rest. An exercise-induced increase in the number of CD3- CD16/CD56+ cells was significantly correlated with the increase in plasma NA (r = 0.66; P = 0.035), indicating a NA dependent process of redistribution. The cAMP-production in MNL was significantly elevated after resistance exercise, when cells were stimulated with 1 mumol.1(-1) isoproterenol [pre-exercise 16.5 (SD 3.3); postexercise 21.6 (SD 9.8); 45 min postexercise 10.7 (SD 2.8)]. The cAMP production in CD4+ cells was not affected by exercise. Therefore, it is discussed whether redistribution is responsible for the exercise induced increase in cAMP production in MNL.

Adult↗
PubMed1994

Detection of numerical and structural chromosome abnormalities in pediatric germ cell tumors by means of interphase cytogenetics.

In contrast to the cytogenetically well characterized testicular germ cell tumors (GCT) in adults, reports on cytogenetic studies in pediatric GCT are scarce. The presence of an i(12p) and numerical abnormalities involving chromosome 12 are the most frequent cytogenetic changes in GCT of adults. We have performed in situ hybridization (ISH) studies on paraffin sections and on isolated nuclei of 13 pediatric GCT with particular emphasis on those chromosome abnormalities that are common in adult GCT. These include numerical and structural abnormalities of chromosomes 1 and 12 as well as numerical deviations of chromosomes 8, 10, X, and Y. The histological subsets of the tumors investigated included two dysgerminomas (DGE), one seminoma (SE), two embryonal carcinomas (EC), four mixed and two pure yolk sac tumors (YST), and one undifferentiated (IT) and one differentiated teratoma (TD). Similar to the GCT in adults, additional copies of chromosome 12 were the most frequently observed numerical abnormalities. In contrast to the findings in adult GCT, changes in the size of the pericentromeric hybridization signals of chromosome 12, suggesting the presence of i(12p) chromosomes, were found in only two cases. No chromosome abnormalities were found in the pure TD or in the TD cells of mixed tumors containing a YST component. In the YST portion, however, Ip deletions and/or numerical chromosome changes were present. Surprisingly, deletions of the short arm of chromosome I, del(I)(p36.3), were frequent in pediatric GCT and were the sole abnormality detected in two cases. The Ip36 deletions were present in all stage-IV EC and YST investigated and were absent in the relatively benign TD and in one YST stage-I. Therefore, Ip36 deletions may have value as a prognostic marker in pediatric GCT.

Adolescent↗
PubMed1994

Experimental studies for clinical standardization of transabdominal laparoscopic nephrectomy.

In keeping with the maxim that minimal invasiveness is the present working trend in most areas of surgery, we investigated the possibility of laparoscopically removing a diseased human kidney. Before any actual clinical attempt could be made in this direction, an experimental study was set up in order to determine the most beneficial methods and techniques which would guide us through our first clinical cases. This step-by-step training program consists of: (1) initial familiarization with different laparoscopic instruments, bimanual dissection, ligation and coagulation techniques, camera handling and trocar placement as well as organ retrieval systems using the lap simulator; (2) laparoscopic removal of the kidney and ureter of the pig either as short- or long-term study, and (3) laparoscopic simulation with the lap tent during open surgery.

Animals↗
PubMed1994

[When patient and therapist disagree--discrepancies in evaluation of change].

The following study concerns the interaction of different measures for therapeutic change. 1377 inpatients of a psychosomatic hospital were examined. Measures for change were the subjective global rating of the inpatient, the subjective global rating the psychotherapist, and the Symptom-Check-List SCL-90-R. To get additional information for possible predictive variables for discrepant judgements, also personality questionnaires and sociodemographic variables were considered. Results demonstrated only medium correlations between subjective ratings for change of the patient and the psychotherapist, although the same categories were used (R = 0.44). The correlations to measures of change of the self-rating-scales are even lower. Therefore we conclude that these measures focus to different information, because the common part of variance is low. Discrepancies between the judgement of therapists and patients can be found after all when the patient makes a negative rating. Predictive variables for discrepancies of the judgements for change of the psychotherapists and patients are: age, sex, phobic anxiety and bodily complaints. While younger patients tend to make better judgements than their therapists we find the contrary for elder patients. Women tend to make better judgements than their psychotherapists. We find also discrepancies in patients with multiple syndromes, when phobic anxiety and bodily complaints exist and are perhaps not adequately concerned in the psychotherapy.

Adult↗
PubMed1993

Detection of Ip36 deletions in paraffin sections of neuroblastoma tissues.

Nonradioactive in situ hybridization (NISH) on sections of paraffin-embedded neuroblastoma tissue was performed to evaluate numerical and structural aberrations of chromosome 1. Two biotinylated probes specific for the heterochromatic (D1Z1) and subtelomeric regions of chromosome 1 (D1S32) were used to study normal tissue and 4 neuroblastoma samples with and without Ip36 deletions. The NISH findings in 3 of the 4 neuroblastomas correlated well with the results obtained by cytogenetic banding analysis. In 1 tumor sample, however, a deletion at Ip36 was observed by NISH, both on metaphase spreads and interphase nuclei, but not by cytogenetics. The NISH method is therefore advantageous when only paraffin-embedded material is available and can be even more sensitive than conventional cytogenetic analyses under certain conditions. Moreover, the technique provides morphological information that cannot be obtained by methods relying on tissue extracts or cell suspensions.

Aneuploidy↗
PubMed1993

[Laparoscopic training in urology. An essential principle of laparoscopic interventions in the retroperitoneum].

The main problem with clinical introduction of laparoscopic techniques in urology is that despite experience with endoscopy no significant endoscopic training is given. Laparoscopic nephrectomy, in particular, is a rather complicated procedure and needs an adequate training concept: The beginner should have the possibility of practising in vitro in a closed "pelvi-trainer" to learn video-optical coordination and orientation; then it is necessary to get used to handling the instruments and practise the different steps of the procedure (i.e. clipping of vessels, sacking of the kidney) either in phantom models or in explanted animal organs. On this basis, we performed laparoscopic nephrectomy in an animal model (n = 18 porcine kidneys). We were able to standardize the technique of creating a pneumoperitoneum, the positioning of the animal, the site and size of the trocars, and preparation and clipping techniques (i.e. Endo-GIA) and entrapment of the kidney (testing different organ bags). A step-by-step approach was used for the introduction to clinical application. For simulation and training of video-assisted preparation techniques in patients and step-wise introduction to laparoscopy (instruments, endocoagulation, trocars), we created a "lap-tent", which was placed over the wound after exposition of Gerota's fascia. Further preparation was performed under laparoscopic conditions (without pneumoperitoneum) with a limited time allowed (1 h). Thereafter, we started with time-limited laparoscopy and laparoscopic lymphadenectomy prior to pelvic surgery (prostatectomy, cystectomy) to introduce the staff to the technique of pneumoperitoneum and placement of the trocars and to the use of the instruments in general. Based on this step-by-step training concept, after a 6-months period we were successful in introducing transperitoneal laparoscopic nephrectomy (TLN) to our clinical routine. So far, we have performed 20 laparoscopic nephrectomies, 1 nephro-ureterectomy, 4 tumour nephrectomies (inducing adrenalectomy), 2 adrenalectomies, and 6 modified retroperitoneal lymphadenectomies. In the lesser pelvis we have experience with 20 laparoscopic varicocelectomies, 23 pelvic lymphadenectomies, and 5 diagnostic laparoscopies for cryptorchidism (February 1993).

Adrenalectomy↗
PubMed1992

Ewing's tumor X mouse hybrids expressing the MIC2 antigen: analyses using fluorescence CDD-banding and non-isotopic ISH.

We present a highly sensitive method that has been applied to map the chromosomal origin of the prominent cell surface antigen of Ewing's tumor cells recognized by monoclonal antibody HBA-71. The technique allows an unambiguous identification of human chromosomal material in interspecific cell hybrids. This is achieved by fluorescent in situ hybridization of biotinylated total human DNA, followed by high resolution fluorescence banding with the chromomycin/distamycin/DAPI triple stain. An advantage of this method is that all signals can be visualized in one single operation by simply switching the appropriate filter blocks. The protocol has proved extremely useful in gene mapping by means of interspecific cell hybrids, a technique that depends on the accurate and unambiguous recognition of the relevant (e.g., human) genetic material in the clonal genome. Our studies confirm that this antigen is the product of the MIC2 gene, which is so far the only well-studied pseudoautosomal gene in man, and which is located on the short arms of chromosomes X and Y. Furthermore, no influence of the Ewing's tumor-specific translocation t(11;22) on MIC2 expression could be discerned.

Animals↗
PubMed1991

Analysis of unstable RNA transcripts of insecticidal crystal protein genes of Bacillus thuringiensis in transgenic plants and electroporated protoplasts.

We have examined expression of several insecticidal crystal protein (ICP) genes of Bacillus thuringiensis in transgenic tobacco plants and electroporated carrot protoplasts. We determined that low levels of lepidopteran toxin cryIA(b) ICP gene expression in plants and electroporated carrot cells is due to RNA instability. We used a series of 3' deleted by cryIA(b) constructs directed by the cauliflower mosaic virus 35S promoter to demonstrate that this instability is minimally contained in the first 579 bases of the gene in both systems. This instability may result from 5'----3' as well as 3'----5' RNA metabolism. The coleopteran toxic cryIIIA gene was also examined in electroporated carrot cells, and found to be poorly expressed. A model for improvement of ICP RNA stability in plants is presented.

Bacillus thuringiensis↗
PubMed1991

Nasal resonometer: an instrument for the assessment and treatment of hypernasality.

We describe an instrument which enables the measurement of the ratio of nasal to oral sound pressures to be made during normal speech. The technique incorporates a novel phase locking technique which effectively discriminates the spectral characteristic of resonant peaks occurring during nasalized speech from other nasal emissions. The results enable an assessment of the degree of resonance in real time, the trend of diagnostic measurements within a treatment session and the success achieved in reaching targets set during treatment.

Adolescent↗