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Biomedical subjects

H Nitzsche

Publications and source records attributed to H Nitzsche.

At least 19 recordsLinked to original sources
PubMed1999

Response of pig lung to irradiation with accelerated 12C-ions.

The response of pig lungs to irradiation with 12C-ions was assessed in two experiments to validate the procedures for heavy ion therapy planning at the Gesellschaft für Schwerionenforschung (GSI) and to explore their range of applicability. In both experiments, the target volume (spread-out Bragg peak, SOBP) was planned to be a 4 cm long cylinder with a diameter of 4 cm. Doses in the SOBP were prescribed to be equivalent to 5x4 Gy, 5x5.5 Gy and 5x7 Gy of x-rays in the first experiment, and to 5 fractions of 7 Gy and 9 Gy in the second experiment. The lung response in the first experiment was less than expected on the basis of earlier experiments with photons. Pneumonitis reaction and chronic fibrotic changes were observed outside the prescribed high-dose region. In the second experiment, the effects were more pronounced than had been expected on the basis of the first experiment. Changes were most intense in the high-dose region, but were also seen throughout the lung along the beam channel. Moreover, significant skin reactions were observed at the beam entrance site in all animals and - less pronounced - at the beam exit site in 3 of the 6 animals. In conclusion, the complex irradiation geometry of the pig lung, the changes of body weight between the two experiments, and insufficient accounting for a change in the relative biological effectiveness (RBE) computation led to substantial deviations of the observed reactions from expectations, the reasons for which could be identified in a subsequent analysis. The less pronounced lung reaction in the first experiment was due to an overestimation of RBE in a preliminary version of the algorithm for its determination. The extension of the fibrotic reaction resulted from the smear-out of the high-dose region due to density variations in tissue structures, respiratory movement, and limited positioning accuracy. The skin reactions at the entrance port reflect the different treatment geometry in the two experiments. The one unexplained observation is the mild skin reaction that was observed in the second experiment at the beam exit site.

Animals↗
PubMed1997

[Ultrasound morphology of peripheral lymph nodes].

Ultrasonography is the predominating method for the diagnosis of altered superficial lymph nodes. According to well defined criteria, the differentiation between benign and malignant nodal disease is possible with a high accuracy. The major concern of diagnosis is the characterization of enlarged lymph nodes, the staging and the long-time control of patients with tumors of the head and the neck and of patients with melanomas. Exemplary typical appearances of altered lymph nodes will be explained. Beside size and shape of the node, it is important to have a close look to its internal structure. The central echogenic hilus, the nodal cortex and their relation has to be noted and excentric hypoechoic structures must be described. According to the literature and to our own experience, it will be shown how reliable the commonly used diagnostic systems are.

Head and Neck Neoplasms↗
PubMed1989

High frequency oscillatory and conventional mechanical ventilation in experimental surfactant deficiency: a study using a new infant ventilator technique.

The performance of a new infant ventilator system had to be evaluated. Technically it is characterized by flow (V)- and pressure (P)-transducers mounted immediately near the endotracheal tube. A microcomputer works as a function generator and governs servo-controllers for V and P thus offering a multiplicity of different modes both of the conventional (CMV) and high frequency oscillatory (HFO) type. The additional dead space imposed by the system is identical with its internal compressible volume of 2 ml. Serial pulmonary lavages were performed in 17 adult rabbits while on CMV. PaO2 per unit of mean airway pressure (MAP) decreased thereby from 95.9 +/- 29.3 to 9.0 +/- 6.7 (kPa/kPa). The animals were then alternately ventilated by HFO (5, 10, or 20 Hz) and CMV, at matched MAP's. No significant difference in PaO2 between the two methods was revealed in intra-animal comparisons except a slight superiority of CMV at MAP's above 1.7 kPa (P less than 0.05). There was no clear linear relationship between PaO2 and MAP both at CMV and HFO. A strong increase in PaO2 often occurred beyond a MAP threshold. In 37 postlavage HFO runs at 5 Hz in 13 animals volume amplitudes of 3.19 +/- 0.5 ml/kg of bodyweight resulted in PaCO2 levels of 6.29 +/- 1.87 kPa. Except in one experiment (10 Hz) volume amplitudes below the natural dead space produced arterial hypercapnia.

Animals↗
PubMed1988

[Invasiveness of lymphadenectomy in penis cancer].

Obligatory statements on the value of lymphadenectomy in penile cancer are difficult because of the rarity of the tumor. Reservations against a general application of inguinal or ileoinguinal lymphadenectomy in penile cancer are made because of severe complications as long-term lymph fistulas, skin necroses, scar contractures, vascular injuries and restrictions of the leg motility. Measures to reduce these complications are of great value. By a special intraoperative and postoperative regimen in our own patients severe complications could be avoided. With the use of absorbable ligation material the development of long-term fistulas is prevented and by a redon drainage of 15 days the development of wound ruptures and scar contractures are avoided. Although in all cases investigated by lymphangiography a lymph flow obstruction was verified only discrete lymph edemas of the lower extremities were found clinically. Thereby an opening of preformed lympho-venous anastomoses due to outflow obstruction and simultaneous tissue compression should be assumed.

Follow-Up Studies↗
PubMed1987

[Diagnostic sensitivity of sonography in varicose and post-thrombotic venous insufficiency].

We report on the application possibilities of sonography in phlebology. Sonographic examination of 131 lower legs showing various clinical forms of chronic venous insufficiency is discussed. Ultrasound offers a timesaving, non-invasive, and reproducible technique to detect insufficiencies concerning orifice or trunk of the great and lower saphenous veins as well as the perforating veins. The method allows varying diagnostic sensitivities. Thrombotic changes in the deep veins may be demonstrated with relative accurateness. As to insufficiencies concerning the epifascial and perforating venous system (in epifascial chronic venous insufficiency, stage I to IV), the question of surgical or sclerotherapeutic treatment can be settled in most cases according to the sonographical findings alone. Subfascial forms of chronic venous insufficiency require additional invasive diagnostic techniques, such as plethysmography, phlebography, and venous pressure measurements. In consideration of the high diagnostic importance of ultrasound, sonographic devices should be available and applied in a large number of phlebologic practices.

Blood Flow Velocity↗
PubMed1985

[The histologically evaluated accuracy of lymphography in operative therapy of invasive cervix cancer stages Ib-IIb].

118 of 129 pre-operative patients with invasive cervical carcinoma of stage Ib to IIb from 1974 to 1978 were examined lymphographically. Abdominal radical hysterectomy according to Wertheim with obligatory lymphonodectomy followed in all cases. Results of the histologic examination of lymphnodes have been compared with the findings from lymphography, whereby a coincidence could be proved in 84 per cent of all cases. The correlation for the lumbar and iliac lymphonodi was listed separately in 75 per cent of the cases. Lymphography gives significantly better results within the lumbar region with an accuracy rate of 92 per cent, a sensitivity of 100 per cent and a specificity of 98.5 per cent. It may be concluded that a lumbar lymphonodectomy is not necessary in the event of a negative lymphography.

Female↗
PubMed1983

[The significance of pelvic lymph-node status in prostatic cancer].

The formation of metastases of carcinoma of the prostate has become more significant since the introduction of en-bloc pelvic lymphadenectomy using the serial-cut method. Lymphogenous evacuation of the pelvis occurs increasingly with advanced and dedifferentiated primary tumours. However, it can be found with low categories of tumours and differentiated carcinomas. pLA is superior to all other procedures for N-determination. If suitably indicated it allows a localized tumour process to be confirmed. Lymphatic oedemas are the most frequent complications. These can be largely avoided by retention of lacunary lymph nodes or primary fitting of lympho-nodo-venous anastomoses.

Humans↗
PubMed1981

[Value of lymphography in prostatic cancer - comparison with pelvic en-bloc lymphadenectomy].

On the basis of 62 pelvic en bloc lymphadenectomies in the carcinoma of the prostate the lymphogenic formation of metastases is histologically determined. In 41 patients the comparison between lymphographic and histological N-determination is performed. The security of the lymphography in the carcinoma of the prostate in the lymphographically establishable pelvic region is recognized with 70%. By the pelvic en bloc lymphadenectomy in 50% of the cases a change of the preoperatively established N-determination takes place. The pedal lymphography is overestimated as method in the carcinoma of the prostate. As a secure technique in the determination of the lymphogenic formation of metastases at present the pelvic en bloc lymphadenomectomy with histological elaboration of the preparations is to be regarded. To this methods belongs a decisive diagnostic evidence in the determination of the formation of metastases of the carcinoma of the prostate by pelvic lymph nodes. The value of the lymphography consists in the simultaneous establishment of aortic metastases. Apart from this an intraoperative X-ray control may partly prove the radicality of the intervention.

Humans↗
PubMed1979

[Lymphogenic metastasis in prostate carcinoma and radiation therapy].

Our examinations allow the following conclusions: 1. Before the beginning of a curative radiotherapy of the carcinoma of the prostate gland in a negative and questionably positive lymphogramme the pelvic lymphadenectomy with histologic examination of the lymph nodes is indicated. 2. In the negative findings of the histologically examined lymph nodes an exclusive local tumour irradiation is justified. 3. If in regional and negative findings micrometastases appear in the area of juxtaregional lymph nodes the additional curative irradiation of the pelvic lymph nodes seems to be indicated for the comprehension of the regional lymph nodes. 4. When there are micrometastases in the area of the aa. iliacae communes or macroscopically extended metastases in the regional and juxtaregional lymph area, so we regard as a rule a radiotherapy of the carcinoma of the prostate gland no more indicated and recommend a contrasexual treatment. The necessary expansion of the radiotherapy is according to our hitherto existing experiences badly tolerated by the for the most part older patients. 5. The intraoperative labelling of the prostate gland and the determination of the size of the prostate gland facilitate the localisation of the tumour for the radiotherapist.

Carcinoma↗