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Biomedical subjects

H Vogler

Publications and source records attributed to H Vogler.

At least 37 records · Page 2Linked to original sources
PubMed1990

Radiobiology of the rhabdomyosarcoma R1H of the rat: influence of the size of irradiation field on tumor response, tumor bed effect, and neovascularization kinetics.

R1H tumors were irradiated with a single dose of 15 Gy X rays using varying sizes of treatment fields. Damage to tumor cells and tumor stroma was determined separately by analysis of growth delay to ten times treatment volume (GD10vo) and net growth delay. GD10vo comprises irradiation effects on tumor parenchymal cells and on tumor stroma, whereas net growth delay only measures effects on tumor parenchymal cells. Stromal damage was observed to increase with increasing field size; the effect on the tumor parenchymal cells, however, was independent of the field size. An increase of GD10vo of 13 days per cm increase of field size diameter was observed. From this the velocity of neovascularization of the irradiated tumor bed was calculated to be 0.30 to 0.38 mm per day.

Animals↗
PubMed1990

Radiotherapy of the rhabdomyosarcoma R1H of the rat: postoperative radiotherapy.

Rhabdomyosarcoma R1H of the rat was excised aiming for a complete macroscopic local excision. Adjuvant radiotherapy was performed from the third postoperative day on. Former tumor sites were locally irradiated with 200 kVp X rays 4 times per week over a period of 6 weeks. Total doses of 0, 15, 30, 45 and 60 Gy were applied. The tumor volume was measured and the time to regrow to initial volume was assessed. The results were compared to the effect of a standard radiotherapy alone with 30 fractions of 2 Gy applied within 6 weeks. All tumors recurred despite of the irradiation treatment. At high total doses (greater than 30 Gy), adjuvant radiotherapy was found to improve short term tumor response considerably, whereas no positive effect was seen at low doses. After a total dose of 60 Gy and long time intervals after start of treatment, radiotherapy alone and a combination of surgery and radiotherapy seem to be isoeffective in our tumor system.

Animals↗
PubMed1990

Flow cytometric determination of the time of metastasis during fractionated radiation therapy of the rat rhabdomyosarcoma R1H.

A technique is presented for determining the time of metastasis during fractionated radiation therapy of the rat rhabdomyosarcoma R1H by flow cytmetric DNA index measurements. The DNA index is the relative DNA content of the tumour cells compared with normal cells. The DNA index of the highly hyperploid R1H tumour decreases linearly during radiation therapy dependent on the total dose applied, with a rate of 0.22% per Gy. Since metastatic cells escape further irradiation, their DNA index should correspond to the DNA index at time of spread. If so, cells disseminated late during a course of fractionated irradiation are expected to produce symptoms later and to have a lower DNA index compared with cells that metastasized at the start of treatment. The results obtained fitted these expectations, showing that timing of metastases by DNA flow cytometry, in principle, is possible. A first application of this method indicates that the risk per clonogenic R1H tumour cell to matastasize increases during fractionated irradiation.

Animals↗
PubMed1989

Radiotherapy of the rhabdomyosarcoma R1H of the rat: hyperfractionation--126 fractions applied within 6 weeks.

The effect of a hyperfractionated irradiation treatment on the response of the rhabdomyosarcoma R1H of the rat was studied. Tumors were irradiated under ambient conditions with 126 fractions of X rays, applied in 3 fractions per day with a time interval of 8 +/- 1 hr between fractions on 7 days per week during 6 weeks. The total dose ranged from 54 to 90 Gy, that is the dose per fraction ranged from 0.43 to 0.71 Gy. Tumor response was assessed by tumor control probability and tumor net growth delay. The tumor response to the hyperfractionated treatment was found to be slightly more effective compared to the results obtained in a previous study where treatments with 6, 18, 30, and 42 fractions were applied. Since normal tissues are considerably spared with increased numbers of fractions, clinical studies with hyperfractionation seem to be very promising.

Animals↗
PubMed1988

Radiotherapy of the rhabdomyosarcoma R1H of the rat: the influence of the number of fractions on tumor and skin response.

The influence of the number of fractions on tumor and skin response to fractionated irradiation was studied. R1H rhabdomyosarcomas of the rat (volume doubling time 3 days) were irradiated with 6, 18, 30, or 42 fractions in 6 weeks. Total doses of 45, 60, or 75 Gy were applied in each fractionation scheme, that is, the dose per fraction ranged from 1.07 to 12.5 Gy. Tumor response was assessed by tumor control probability and tumor net growth delay. A clearcut reduction of skin damage was observed with increasing number of fractions, whereas the tumor response was found to be the same whether the dose was given in 6, 18, 30, or 42 fractions. Thus, the fractionation regimens were more effective than expected from calculations based on single-dose in situ survival curves. This result can be explained by assuming that the clonogenic tumor cells become less hypoxic with increasing number of fractions. Since normal tissue damage decreases with increasing number of fractions, the therapeutic gain may be improved by applying a greater number of fractions.

Animals↗
PubMed1988

Radiotherapy of the rhabdomyosarcoma R1H of the rat: kinetics of cellular inactivation by fractionated irradiation.

The kinetics of cellular inactivation by fractionated irradiation in the R1H rhabdomyosarcoma of the rat was studied in the dose range of 1.07 to 12.50 Gy per fraction. Regimens of 1, 3, 5, 7, and 10 fractions per week for several weeks were compared. The number of clonogenic tumor cells per tumor in the course of the different treatment schedules was determined using an in vitro colony assay. The results show that the proliferation of clonogenic tumor cells is decelerated in the course of a fractionated radiotherapy. The deceleration persists for several days after end of treatment, until accelerated repopulation is initiated. The fraction of tumor cells inactivated per week was only dependent on the total dose per week, that is the cellular response was the same whether the weekly dose was applied in 1,3,5,7, or 10 fractions. Thus, the fractionation regimens were considerably more effective than expected from calculations based on single-dose in situ survival curves.

Algorithms↗
PubMed1987

Net growth delay: a novel parameter derived from tumor growth curves.

Growth delay does not only reflect the effect of treatment on the tumor parenchymal cells but also on the stroma. Due to tumor bed effect, the extent of growth delay determined from tumor growth curves is highly dependent on the end volume chosen. It was aimed to minimize the influence of the tumor bed effect on the growth delay calculated by choosing a smaller size and essentially an earlier time for regrowth. Net growth delay is a novel parameter derived from the tumor growth curves, allowing a better comparison of the results with colony assay and tumor control data.

Animals↗
PubMed1987

[Can high-frequency currents in transurethral resections lead to urethral strictures?].

During transurethral resections measurements of the high-frequency tension yielded on the shaft only 8-10% of the tension at the loop. At the beginning of every operation the tension at that loop was measured where first tissue reactions appeared. It is approximately 24 V during cutting. By means of the estimation of the field intensity by simultaneous measurement of the tension in the symphyseal area and by theoretical estimation of the field intensity is shown that, when properly used, a damage by the high-frequency current cannot appear.

Electric Conductivity↗
PubMed1987

[Value of computerized tomography of the thorax in germinal testicular tumors].

Sporadic informations in the literature that by means of CT of the thorax by far smaller intrapulmonary foci can be recognized in comparison to the conventional x-ray examination are just to be confirmed. With the help of instances the indication for thorax CT in germinal testicular tumours is presented. The evidence and exclusion, respectively, of pulmonary metastases are of decisive importance actually for the therapy and prognosis in patients with germinal testicular tumours. In this respect our observations confirm the indications for a CT-examination of the thorax in these groups of patients.

Adult↗
PubMed1986

[Is Teflon treatment of female urinary incontinence still justified?].

An analysis is made in this paper of therapeutic results obtained at Charité Berlin from 14 cases of pure stress incontinence and 6 cases of combined stress-urge incontinence, with reference being made to general benefits and setbacks of transurethral Teflon injection to cope with female urinary incontinence. Five women underwent teflon therapy as the first operation performed on them. Seven women had had one operation before and the rest more than one. Continence was restored in 6 patients (30 per cent), and 3 patients (15 per cent) were improved. The presurgical situation was of minor influence. The definite result was outlined as early as three months from surgery. Urodynamically, Teflon had a favourable impact primarily on functional urethral length and on the stress quotient. However, elevation of the bladder base was radiographically detectable in less numerous cases. Only partial agreement was found to exist between objectivated improvement and subjectively perceived and reported therapeutic results, with falsely positive and falsely negative findings occurring with equal frequency. Micturition was insubstantially impaired by Teflon. However, it should be adopted as a matter of principle that in future teflon should no longer be applied to women for urinary incontinence unless conservative therapy or other surgical incontinence techniques must be skipped for whatever reasons and unless no more effective sphincter substitute is available.

Adult↗
PubMed1985

[Consequences for military medicine of new nuclear weapons developments].

The development and production of qualitatively new nuclear weapons (e.g. neutron weapons) has consequences also for the medical protection under conditions of war. In the present paper the peculiarities of these new systems of arms as well as the profile of injured persons which is to be expected after use of neutron weapons are analysed and general conclusions for the medical service are drawn.

Dose-Response Relationship, Radiation↗
PubMed1983

[Urethroplasty against endoscopic urethrotomy].

From 1970 to 1981 urethroplasty was done in 79 patients and internal urethrotomy under vision was done on 166 urethral strictures from 1977 to 1981. We feel that urethroplasty and internal urethrotomy complete each other. Both of them are successful in some 85% of cases. Direct vision cold knife internal urethrotomy increases the scope of our surgical possibilities in urethral strictures. It should normally be the first treatment. Internal urethrotomy can be performed in all types of urethral strictures. The patients are not severely affected. The advantage of this method is that it can be used at an old age, too. In acute urinary retention as a consequence of urethral stricture internal urethrotomy can also be utilized. It can be done in a second or third procedure. If urethroplasty must be done after internal urethrotomy all surgical possibilities remain. We prefer urethroplasty for long strictures, especially in the membranous urethra, and multiple strictures.

Cystoscopy↗
PubMed1982

[Antineoplastic chemotherapy in the therapeutic plan of germinal testicular neoplasms].

The therapy for germinal testicular tumours consists in a combination of operative measures, irradiation and antineoplastic chemotherapy. There are 2 indications for lymphadenectomy: staging operation and removal of metastases. Irradiation is indicated for seminomas at all stages, but even in the case of non-seminomas it reduces the rate of recidivation and increases the rate of survival. Disseminated non-seminomas are the domain of antineoplastic chemotherapy. Adjuvant chemotherapy is increasingly being used in the second stage. We treated 274 patients with germinal testicular tumours (44% seminomas, 56% non-seminomas in ther period 1964 - 1981. We carried out curative chemotherapy in 36 patients in stage III. A complete remission was observed 23 times. For patients with non-seminomas the results of treatment in 2 different therapy groups can be compared: Group 1: orchiectomy and irradiation, Group 2: Orchiectomy, lymphadenectomy, chemotherapy and irradiation. The survival rates (states I and II) are 52% after 2 years and 44% after 5 years in the first group. In the second therapy group these rates are 80% and 75% respectively.

Antineoplastic Agents↗