Role of humoral immunity in pancreatic islet allo- and xenograft rejection.
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Animals↗
Biomedical subjects
C Sohn
Publications and source records attributed to C Sohn.
[Laparoscopy in (apparently) benign ovarian tumors between benefit and catastrophy and the deceptive safety of laparoscopic lap sacs].
Endoscopic ovarian surgery is currently spreading tremendously, but also rather uncritically. The technical possibilities both of organ preserving and ablative endoscopic surgery are controversial, so that structuring of the indication for an endoscopic procedure as well as optimization of the endoscopic removal of ovarian tumor or adnexae is of utmost relevance. Therefore, a study was performed at the Department of Obstetrics and Gynaecology of the Heidelberg University with the following aims: Risk evaluation of operating into an ovarian malignancy at endoscopy for "presumably" benign cystic ovarian tumors in n = 100 cases in Heidelberg and literature survey Analysis of problems and complications during clinical application of laparoscopic lap sacs for removal of cystic adnexal tumors or adnexae (n = 50) Experimental examination of the risk of an endoscopic lap sacs to rupture during a procedure The risk of endoscopically operating into an ovarian cancer lies between 0.4 and 3% according to literature data. Despite maximal preoperative selection, mainly by ultrasound examination, in our group of 100 patients, in three women without preoperative signs of malignancy but with discreet intracystic structures in the ultrasound, an endoscopic adnexectomy with complete removal in a lap sac was performed, and though immediate section for microscopic examination was negative, final histology revealed one ovarian cancer la and 2 borderline tumors, same stage. In the time period analyzed, three further patients were referred to our center for secondary, delayed (median 3 months) staging after endoscopic procedures for presumed benign lesions. Clinical application of lap sacs proved the necessity of an intensive training. In 3 patients an intraperitoneal rupture of the sac occurred. Typical problems were volume discrepancies between sac respectively abdominal incision and tissue to be removed (28% of cases). The risk of rupture of the various lap sacs examined differed significantly (p < 0.05). Due to the complex pathological nature of cystic adnexal tumors, a 100% selection for the endoscopic approach is not feasible. Therefore, an endoscopic procedure should only be performed after optimal preoperative diagnosis and, in case of the slightest doubt, only if intraoperative microscopic examination is available, and the possibility to perform an immediate staging laparotomy. Sufficient information of the patient is relevant. Laparoscopic removal of tumor or adnexae should be performed in a lap sac. However, there is no absolute certainty of preventing spillage even with the lap sac, since not all endoscopic sacs available are of a sufficient quality.
Adult↗
[Possibilities of laparoscopic ultrasound diagnosis].
Both pre-operative transvaginal sonography and laparoscopical diagnosis leave gaps in the diagnosis of adnexal tumors. The combination of both methods seems to fill these gaps. For diagnosis with Laparoscopical Sonography a special scan head is needed: After removing the optical components there was a little linear-array installed into the original gastroscope with a diameter of only 9 mm which enables maximum flexibility during examinations. The linear-array consists of 128 crystals with a frequency of 7.5 MHz (penetration depth: 6 cm), enabling B-Image Sonography, Pulsed and Color Doppler as well as Angio-Color-Technique. Laparoscopical Sonography in addition to transvaginal and transabdominal sonography leads to progress in diagnosis and therapy. As the scan head can be placed directly in front of the area which is normally hardly detectable diagnosis is possible and plannings for the further operations as well as color-doppler controls during operations can be improved. In several cases this method allowed detection of metastases of the liver which were not visible by transabdominal ultrasound.
Equipment Design↗
[What is the reliability of conventional ultrasound mammography and color coded ultrasound in diagnosis of breast tumors?].
To establish the diagnostic relevance of sonographic blood supply measurement for tumor's nature evaluation, 192 women with suspect unilateral breast findings were examined on the preoperative day with color coded sonography (MEM color technique). A combination of evaluation in B-scan and color mode resulted in a sensitivity of approx. 96% in cases of malignant tumors (121 histological findings of breast cancer). Specificity in the 71 patients with a histologically benign diagnosis was of over 90%. Despite an essential improvement in dignity diagnosis, histologic proof is, however, necessary, even in cases of benign findings at the diagnosis. Since a 100% certainty in the differentiation of benign and malignant tumors will never be achieved with ultrasound techniques, biopsy specimen will have to be taken. Thus additional measurements of tumor blood flow seems of no clear advantage for the patient. In our opinion, the essential contribution of blood flow diagnosis of malignant tumors lies rather in the evaluation of tumor prognosis, since the differences in the blood supply of malignant growths are indicators for their biological behavior.
Adult↗
[Diagnostic value of Doppler ultrasound in evaluation of breast tumors].
Angiogenesis is an essential condition for tumor growth. Therefore, it seems to be of interest to prove if blood flow and vascularization of breast tumors give information concerning their dignity. Consequently, 205 patients with palpable and/or mammographically detected breast tumors were examined prior to surgery by doppler sonography for blood flow in the area of the tumor. In 174 patients of this group the corresponding area of the contralateral breast was also screened by doppler ultrasound. With third doppler generation angiodynography tumors can be visualized as B-images with simultaneous information on vascularization. An integrated doppler system shows the detected blood flow in form of a doppler curve, also allowing quantification according to doppler criteria (Resistance Index RI). Blood flow detection in the tumor itself was successful in 71% of all malignancies, whereas in only 6.6% of the 76 benign lesions (n = 5) blood flow was found in the central tumor area. In the area surrounding the tumor blood flow was detected in 83% of all carcinomas, but only in 29% of benign findings. Blood flow could be detected significantly higher in malignancies than in benign lesions (p = 0.003). Blood flow detection in the tumor itself was a highly specific (93%) method of discrimination between malignant and benign breast tumors. Further quantification by means of doppler parameters only increases insignificantly specificity, quantification of blood flow in the area surrounding the tumor using the RI and the comparison with the contralateral breast could improve the diagnostic value as our findings RI < 8 for benign vs. > or = 8 for malignant lesions demonstrated. Detection of malignant tumors showed a sensitivity of 80%, a specificity of 90%, and a positive predictive value of 93%. In patients with breast cancer (histologically confirmed) the detection rate of blood flow in tumors and surrounding areas was independent of tumor size or nodal status.
Blood Flow Velocity↗
Initial results of intraluminal ultrasound in gynecologic diagnosis.
The interior of hollow organs can be examined using extremely small intraluminal ultrasound transducers inserted into catheters. We tested the practicality of this method and the range of indications for which it could be useful in gynecology by performing initial examinations of extirpated uteri and fallopian tubes. In vivo, we inserted an intraluminal unit with transducer diameters of 3.5F and 5F through the cervix into the fallopian tubes of 15 patients during hysteroscopy or laparoscopy. The catheter was inserted successfully into the tube in all 15 women, and in 9 all the way to the distal end. The tubal wall was identified precisely, and a functional diagnosis of tubal motility was established for the first time. However, it was impossible to differentiate between tubal epithelium and muscularis. Also, uterine endometrium cannot be evaluated accurately with the current level of technology. This technique will enable the first functional examination and diagnosis of the tubes and uterus, provided that further improvements can be made in the quality of the images.
Catheterization↗
Differential diagnosis of mammary tumors with vocal fremitus in sonography: preliminary report.
During sonographic examinations using the new color Doppler technique, maximum-entropy method (MEM), it was discovered, by chance, that artefacts which are produced by vibrations of the thorax can be used to differentiate between malignant and benign breast lesions. These artefacts, in the form of small color pixels, can either be brought about by vocal fremitus known from internal medicine or by humming in a low tone. In the case of malignant tumors, the color pixels are visible in the middle of the sonographically portrayed tumor as well as in the surrounding tissue, whereas in benign tumors the artefacts are only found in the surrounding tissue and are quite clearly not present in the center of the tumor. On the preoperative day, 95 patients with 46 benign and 49 malignant lesions were examined using the method described above. In 91% the differential diagnosis was in accordance with the histological results. In seven cases a benign lesion was classified before the operation as malignant and in two cases malignancy was incorrectly diagnosed as benign. Our explanation of the phenomenon is based on the fact that most benign tumors exhibit a restricted growth and form a clear-cut boundary with the surrounding tissue, so the vibrations are not conducted into the tumor. In contrast, malignant lesions grow by infiltrating the surrounding tissue, allowing the vibrations to be conducted into the tumor, where they can be demonstrated as small color pixels.
Artifacts↗
[Initial experiences with laparoscopic intraoperative ultrasound].
Preoperative ultrasound as well as intraoperative laparoscopic diagnosis have both their limits, a fact that might be significant for laparoscopic surgical management. In particular, since in this surgical domain, where almost everything has become technically feasible, the operator must decide what is to the benefit of the patient. A possible solution could be laparoscopic ultrasound, i.e. ultrasound diagnosis per laparoscopy at the very site of the lesion. The advantages are evident. Due to the closeness to the organ to be examined, the frequency of the scan head can be extremely high, resulting in better resolution. Also, structures could be visualized by ultrasound which e.g., due to adhesions cannot be seen with the laparoscope. Moreover, ultrasound offers a view into the structures which can be seen only from the exterior with the laparoscope. To perform these examinations we used a specially designed scanhead (Toshiba): Instead of the optical system a crystal array was inserted into a conventional gastroscope. The result was a high resolution 7.5 MHz linear array at the distal end of a freely movable gastroscope. Colour doppler sonography is feasible with this scanhead. We examined 19 patients, 16 of them with ovarian tumours, and attempted visualization of the uterine myometrium/endometrium as well as of the liver. In six cases of ovarian tumours in which only cystic structures were found by preoperative transvaginal sonography, laparoscopic ultrasound additionally revealed solid inner structures. In 5 cases direct laparoscopic view of the ovarian lesions was impossible due to severe adhesions. They were, however, easily detected by intraoperative ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)
Equipment Design↗
[Meniscus ultrasound: a refresher course].
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Humans↗
[Ultrasound blood flow measurement in malignant tumors is a possible new prognostic factor].
OBJECTIVE: The aim of the present study was to find a possible relationship between biological behavior of breast cancer and sonographically detectable blood flow. METHODS: 157 patients with ductal invasive breast cancer were examined by means of a new sonographic procedure, the MEM (Maximum Entropy Method), able to detect considerably lower blood flow velocities than doppler sonography. In the absence of objectifyable quantification methods, findings were allotted to 3 classes, depending on the visual color information obtained. Blood flow was correlated to tumor size, lymph node and receptor status, ploidy and S-phase-fraction. RESULTS: Most patients with small tumors, no lymph node metatases, positive receptors, diploid genome and low S-phase found to have low blood flow. CONCLUSION: This close relation between established prognostic factors and results of sonographic blood flow examination with the MEM might indicate a new preoperative prognostic factor, which, however, will have to be proven by larger studies.
Biomarkers, Tumor↗
[Initial experiences with a new color technique: ultrasound angiography].
The sonographic diagnosis can be expanded by Color Doppler. Nevertheless something is missing, especially concerning the demonstration of the very slow velocities as it can be found in neovascularized malignant tumors. A recently developed new color technique--the Angio-Color of the Diasonics Corporation, Sonotron (other companies have prototypes of this color)--promises to improve the detection of very low flow velocities. Due to a method very different to the conventional Doppler technique the registered signal is coded in the color image of the blood flow: that means that the amplitude and not the frequency shift is coded in color. Therefore there is less noise in the color mode with the possibility of showing the lower flow in comparison to the conventional Doppler. In Gynaecology and Obstetrics the advantages in the demonstration of the placental blood flow were obvious. In eutrophic fetuses the blood flow could be registered over the whole breadth of placenta, while in dystrophic fetuses this was possible only at the margin of the placenta with some color pixels in the middle of the organ. The conventional Color Doppler was not able to show the flow in the placenta even in eutrophic fetuses. Also the flow in fetal organs produced different results using both methods. So the angio-technique showed more color pixels in the periphery. In 8 malignant breast tumors both methods were able to show blood flow, but the Angio-Color showed more color pixels as the conventional color did.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Flow Velocity↗
[Possibilities and limits of a new color technique: ultrasound angiography--results of the "Heidelberg Round Table Discussion"].
Sonographic diagnostics has been essentially enlarged by blood flow measurements with the color Doppler technique. Nevertheless, the method has certain limitations, especially when employed to visualize extremely slow blood flow velocities, which occur e.g. in malignant tumors due to neovascularization. Recently, a new technique, the so-called angio-color procedure, has been presented, which is supposed to overcome the above-mentioned limitations. The way of coding the signal differs considerably from that in conventional color Doppler: The amplitude is color coded, not the frequency deviations. Results and first experiences with the new procedure in various domains were discussed at a 'Heidelberg Round Table' and are summarized in the present article. In the obstetrics/gynecology there are clear advantages in the representation of blood flow in the placenta. In eutrophic fetuses a blood flow over the entire placental breadth was detected, in dystrophic fetuses, however, only on the margins of the placenta. Conventional color Doppler could not visualize blood flow in the placenta at all. Blood flow assessment in the fetal organs also provided different results with the two procedures: the angio-color method showed color pixels even in the peripheral areas. In 8 malignant breast tumors the same observation was made, the angio-color procedure seemed to visualize more color pixels. In 4 of 6 benign lesions blood flow could be measured with the traditional color Doppler, but in 5 of 6 patients with the angio-color Doppler. This was also observed in ovarian tumors. Angio-color representation of renal transplants with normal function resulted in blood flow information reaching deep into the renal capsule, whereas in cases of renal transplants with impaired function a clearly reduced perfusion was visualized. These differences were not so evident with the conventional Doppler method. In lymph node diagnosis, too, marked differences between malignant and reactive lymph nodes could be visualized. In the diagnosis of arteriosclerotic plaques, blood flow in the residual lumen could also be detected more exactly with the angio-color technique. Color representation of liver tumors also showed a higher color signal density with ultrasound angiography. In summary, ultrasound angiography can provide additional information in the color representation of vessels with slow flow velocities. However, an obvious problem is the unability to quantify detected low blood flow. The new procedure will not replace but usefully complete the established sonographic techniques.
Arteriosclerosis↗
[Does measurement of absolute velocity by Doppler examination of pregnant patients contribute additional valuable information?].
Ultrasonics is very important for the control of risk pregnancies. Routinely, Doppler-ratios are used to assess fetal danger. The aim of the presented study was to clarify whether measurement of absolute blood flow velocity is useful for the assessment of fetal development as well. For this purpose we examined the fetal aorta in 149 patients: 90 patients with fetal growth retarded fetuses and 59 patients with normally developed fetuses. Systolic and diastolic peak velocities and the resistance index (RI) were measured. The absolute velocities did not show any correlation to the fetal growth. Moreover, there was no correlation between systolic peak velocity and resistance index, independent of degree of pathology. The diastolic peak velocity however correlated with high significance to the RI thus being directly dependent.
Aorta, Abdominal↗
[Ultrasound diagnosis of fetal lung maturity].
The immaturity of the fetal lung and the resulting respiratory distress syndrome are the main problems of obstetrics. Over a long period of time the only possibility to recognize the maturity of fetal lungs certainly was the determination of the L/S-ratio by amniocentesis. Two years ago first results were presented to determine fetal lung maturity by sonography. We examined 428 patients between 29 and 40 completed weeks of gestation. By comparing the characteristics of frequency of fetal lung echoes to those from the fetal liver as a reference organ it becomes possible to standardize fetal lung changes with gestation. In one ultrasound section we depicted lung and liver as well. According the A-mode we registered frequencies of both. The registered frequencies were entered digitally into a computer to evaluate the mean, maximal and minimal frequencies. Afterwards quotients of the frequencies of fetal lung and liver were calculated. For all weeks of gestation, mean values and standard deviations were made. It has been shown, that the liver is an adequate reference organ since the reflection pattern between the different weeks of gestation does not change, however significant changes have been seen in the fetal lungs. Q-mean, the quotient of fetal lung and liver reflection can be calculated. A quotient of Q-mean < 1.10 suggests lung maturity, while values > 1.10 speak for immaturity. Ultrasound examinations with 55 expectant women were compared with the lung conditions after delivery. 30 examinations were correlated with the results of the L/S-Ratio by amniocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)
Amniocentesis↗
[Effectiveness of beta-hydroxyethylrutoside in patients with varicose veins in pregnancy].
Pregnancy is a critical risk for development of varicosis, therefore early detection and treatment are strongly recommended. In our study we examined 51 patients subdivided into three groups. One group underwent physical therapy (cold foot-baths in the morning an in the evening), the other group was administered beta-hydroxyethyl rutosides, and the patients of the third group had appeared only once for examination. Leg circumference and diameter of vein (by sonography) were measured, and the subjective criteria evaluated. In the group of patients who were additionally given drugs, a significant reduction of all parameters was found: leg circumference was reduced by 3% and diameters of veins were reduced by 15% on average, the reduction of the subjective criteria was by 34%. Provided the veins were prevented from further extension through progressive varicosis, apparent beneficial clinical effects can be achieved by administration of beta-hydroxyethyl rutosides.
Adult↗
[Hysteroscopic endometrium ablation in "high-risk" situations and in hemorrhagic diathesis].
A hysteroscopic endometrial ablation (HEA) under maximal anesthesiologic surveillance was performed on 34 high-risk patients (group I: chronic anticoagulant therapy n = 26; group II: endogenous coagulopathy n = 8) with therapy resistant meno-metrorrhagia to avoid a hysterectomy (HE). Total amenorrhea, or a least hypomenorrhea respectively cyclic spotting could be attained primarily in 22 patients (group I: 19; group II: 3), after a repeat procedure in further 6 patients (4 in group I, 2 in group II). Subjective evaluation of surgical results (overall 22 patients primarily satisfied, 6 secondarily) also differed between the two subgroups (group I: p < 0.01 primarily satisfied; p < 0.05 secondarily satisfied vs. p < 0.05 and p < 0.01 in group II). A HE had to be performed on two patients due to extensive adenomyosis uteri interna (group II). The significantly better results in the anticoagulation group were probably due to the basic illness. Larger groups will, however, be necessary before any conclusions from this difference can be drawn. No surgical or anesthesiological complications occurred. There also were no major postoperative complications (1 endomyometritis, 2 cervical stenoses). Endometrial ablation was found to be a valuable treatment alternative for this specific group of patients with severe coagulopathy, thrombo-embolic or thrombotic disease.
Adult↗
Diagnostic value of pelvic examination, ultrasound, and serum CA 125 in postmenopausal women with a pelvic mass. An international multicenter study.
BACKGROUND: In a prospective study, the differential diagnostic potential of pelvic examination, ultrasound, and serum CA 125 assay in postmenopausal patients presenting with a pelvic mass was assessed. METHODS: A total of 228 patients were evaluated preoperatively in an international, multicenter, prospective study using a standard protocol for pelvic examination, transvaginal (occasionally additional abdominal) ultrasound, and serum CA 125 determination with a cut-off level of 35 U/ml. RESULTS: Ninety-five malignant (41.7%) and 127 benign (55.7%) pelvic tumors were found in addition to 6 borderline ovarian tumors (2.6%) in the 228 patients. Seventy-two patients had ovarian carcinoma, 49 of whom were International Federation of Gynecology and Obstetrics Stage III or IV. Borderline tumors were excluded from the statistical calculations. The individual accuracy of pelvic examination, ultrasound, and serum CA 125 in discriminating between benign and malignant pelvic masses was approximately the same (76, 74, and 77%, respectively). Using logistic regression analysis, the power of pelvic examination appeared to be the most relevant factor (adjusted odds ratio, 9.2), followed by serum CA 125 (odds ratio, 5.6), and ultrasound (odds ratio, 4.9). Age appeared to be nonpredictive. No cancer was found in any patient in whom all three methods scored negative (n = 53; positive predictive value for malignancy = 0 and 95%; confidence interval, 0-7). CONCLUSIONS: The combined use of pelvic examination, ultrasound, and serum CA 125 leads to improved discrimination between malignant and benign pelvic masses, because malignancy can be excluded when all three examination methods are negative. A change to a more patient-tailored surgical approach could be considered in those cases.
Aged↗
[Hysteroscopic endometrium ablation to avoid hysterectomy in "high risk" patients].
Hysteroscopic endometrial ablation under maximal anaesthesiological surveillance was performed in 34 high-risk patients to avoid hysterectomy. It was a collective of patients with heavy thrombo-embolic or thrombotic disease, either under permanent anticoagulation due to residual disease or multiple endoprosthetic treatment, or with endogenous coagulopathy. In all these women, hysterectomy was either a relative or an absolute contraindication. In 22 patients, treatment resulted in complete amenorrhoea or at least hypomenorrhoea (without menometrorrhagia) respectively cyclic spotting. In 6 further patients, amenorrhoea was achieved after a repeat procedure. Endometrial ablation was thus successful in 28 of 34 cases. In these patients, hysterectomy with the risk of major or even lethal complications, could thus be avoided. Hysterectomy, however, had to be performed in 2 women with extensive adenomyosis uteri interna. Within two respectively three years after endometrial ablation, two other patients died from causes unrelated to the surgical intervention (cardiac infarction, cerebral haemorrhage). Follow-up ranged from 1 to 5 years. Hysteroscopic endometrial ablation proved an effective therapeutic option in this selected group of patients. Other indications require further study.
Adult↗