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Biomedical subjects

D Latz

Publications and source records attributed to D Latz.

29 records · Page 2Linked to original sources
PubMed1993

Sensitivity of neutral filter elution but not PFGE can be modified by non-dsb chromatin damage.

Hamster V79 fibroblast cells and human squamous carcinoma cells (Caski) were exposed to 60Co radiation and DNA double-strand break (dsb) induction was analysed by DNA elution at neutral pH from polycarbonate filter or out of an agarose matrix in pulsed-field electrophoresis (PFGE). While dsb yields were equal for the two cell lines (using 125-iodine calibration) a reduced responsiveness of filter elution was found for V79 versus Caski cells. This difference could be abolished when additional single-strand breaks (ssb) were introduced by an incubation at 10(-4) M H2O2 for up to 40 min that itself did not give a response in neutral elution. No such lack of specificity for the detection of dsb was seen in electrophoretic elution where also the influence of peroxide incubation was absent. The presumed potential of ssb to modify dsb detection was paralleled by the kinetics of dsb rejoining: a pronounced transient increase of DNA elution from filters was observed for V79 cells (less prominent with Caski cells) at 15-40 which is thought to reflect the occurrence of secondary ssb from incisions during base damage repair. Rejoining measured by PFGE did not show this behaviour. The results suggest that ssb may aid decondensation of the chromatin during lysis of cells required for an efficient release of dsb fragments when supported on filters, but which depends on cell type and is less critical in electrophoretic elution out of an agarose matrix. This involvement of ssb in the neutral filter elution assay appears to be contrary to published data obtained with different experimental systems. The finding of an increase of DNA elution from filters due to hyperthermia at 45 degrees C is also taken to indicate an involvement of non-dsb chromatin damage in the response of filter elution at neutral pH with V79 but not with Caski cells.

Animals↗
PubMed1993

[The value of radiotherapy in the treatment of Pancoast tumor of the lung].

In a retrospective study 48 patients with sulcus-superior-tumors were treated between 1982 and 1992. The patients were divided into three treatment groups. Group I (n = 6) received palliative irradiation because of distant metastasis. Group II (n = 22) was treated with irradiation alone and group III (n = 20) received preoperative radiation therapy, 15 patients out of this group received a postoperative radiotherapy. The median doses were 56 Gy (group II) and 58.25 Gy (group III). Only in the combined treated group long-term survivors were found (18% five-year-survival). Our results show a benefit for the combined treated patients on a low significant level. For the interpretation of the results it has to be taken into account, that there was a "selection bias" for the combined treated group.

Adult↗
PubMed1993

[The primary radiotherapy of inoperable or recurrent pancreatic carcinoma--Heidelberg patients from 1982 to 1992].

Between 1982 and 1992, 34 patients with locally advanced or relapsed adenocarcinoma of the pancreas were treated at the Department of Radiotherapy in Heidelberg. 14 patients were treated with a combined radiochemotherapy with 5-FU, the other patients were irradiated alone. In all cases irradiation was done with high energy photons. 15 patients received an irradiation with doses between 30 and 44 Gy, and twelve patients between 45 and 66 Gy (median 50 Gy). Seven patients were treated intraoperatively during an exploration laparotomy with fast electrons (10 to 18 MeV, 15 to 20 Gy) and postoperatively with additional 30 to 41 Gy. The median survival of the patients treated with the higher doses or in combination with the IORT showed a significant advantage of nine vs. 2.9 months. There was no benefit in median survival for the patients treated with radiochemotherapy. In retrospective analysis of the percutaneous treated patient collective a pain relief was observed in nine patients. In the prospective treatment protocol of the IORT in 4/4 patients a pain relief was rapidly reached.

Adenocarcinoma↗
PubMed1993

Tumor response to ionizing radiation and combined 2-deoxy-D-glucose application in EATC tumor bearing mice: monitoring of tumor size and microscopic observations.

The present study deals with the changes induced by two fractionation schedules (5 x 9 Gy and 10 x 4.5 Gy; 30 MeV-electrons) of ionizing radiations and 2-deoxy-D-glucose (2-DG) application on EATC tumor bearing swiss albino mice. The monitoring of tumor response was carried out by means of caliper measurement on the macroscopic level and by histopathological examination of tumor preparations stained with hematoxiline and eosine on the microscopic level. The tumor material was assessed at suitable intervals after treatment by killing the animals. The tumor response was analysed in the histological preparations and the thickness of the tumor band was determined quantitatively by an ocular micrometric technique. Tumor damage was most extensive in the combined treated animals (5 x 9 Gy + 2-DG). Only in this group local tumor control was achievable. The histological analysis of tumor preparations revealed additional data about treatment-induced changes in the tumor compared to the measurement of the tumor volume with mechanical calipers. We also found that the treatment outcome could be predicted from the histopathological analysis. It is concluded that studies involving histopathological examinations may give some insight into the way cancer is controlled by radiotherapy and may be of value in prognosis and selection of treatment in patients.

Animals↗
PubMed1992

[Radiotherapeutic results in the treatment of craniopharyngioma].

From 1974 to 1985, twelve patients (seven children and five adults) with craniopharyngioma received megavoltage external beam radiation therapy at the University of Heidelberg. All patients had biopsy proven diagnosis. Nine patients received irradiation after incomplete surgical removal. Three patients were irradiated primarily because of inoperability. In all cases irradiation was applied by a rotation technique with 42 MeV photons. A mean dose of 52.2 Gy (ranged from 46 to 60 Gy) was administered at 2.0 Gy per fraction. In one case radiotherapy was broken off on account of the development of a hypoglycemic coma of unknown genesis. The mean follow-up period amounts nine years up to now. Local tumor control was achieved in nine patients. Two deaths occurred from tumor progression, after temporary improvement. In all cases no radiation related neurological, ophthalmological or endocrine side effects were observed.

Adolescent↗
PubMed1992

[The radiotherapy of Castleman's lymphoma].

The angiofollicular lymphoid hyperplasia, first described by Castleman, is a benign lymphoma. The authors report a very rare case of Castleman lymphoma in the parotid gland. The tumor was successfully irradiated with 40 Gy fast electrons. Treatment planning and therapy monitoring were done by means of ultrasound and computed tomography.

Adult↗
PubMed1991

[Effects of lonidamine alone or in combination with radiotherapy on survival and metabolism in human and rodent cell lines].

In vitro investigations on the combined effect of radiation and Lonidamine in one human (LXI) and two rodent cell lines (3T3, V79) showed not a clear radiosensitizing effect. Especially no inhibiting influence on the repair of potentially lethal damage of V79 cells was found. Incubation at lower pH values (6.7 to 6.9) caused no increasing effects. Lonidamine induced damage on the mitochondrial dehydrogenase-system was quantitatively measured with a modified MTT-assay.

Adenocarcinoma↗
PubMed1991

[Metastasizing malignant meningioma: a case report].

A case of metastasizing malignant meningioma is discussed concerning the etiology, clinical symptoms, diagnosis and therapy. The necessity of irradiation after surgery is turned out. Palliative treatment of bone metastasis is presented from an orthopedic point of view.

Adult↗
PubMed1991

[Additive effects of carboplatin (CBDCA) and Co-60 gamma rays in human tumor cells in vitro].

In vitro investigations on the combination effect of radiation and carboplatin (CBDCA) in three human cell lines (HeLa, MRI-186 Caski) show purely additive effects. Study of the molecular lesions gave considerable differences in the time course of repair of radiation induced DNA-double strand-breaks and of formation of DNA-crosslinks by carboplatin. However, sequential treatment with intervals of up to +/- 24 hours resulted also in an additive effect. In the experimental systems studied, a true radiosensitization was not demonstrated.

Adenocarcinoma↗
PubMed1990

The RBE of euoxic and hypoxic Ehrlich ascites tumour cells irradiated with negative pions in vitro and in vivo.

Ehrlich ascites tumour cells (EAT-F5) were irradiated in vitro with the sparsely ionizing "plateau pions" and with the more densely ionizing "peak pions". From cell survival curves obtained under euoxic and hypoxic conditions, the RBE for the production of irreparable lethal and potentially lethal damage was derived. Cells of the same strain were used to produce solid tumours in the leg muscle of mice. Survival of these cells irradiated in vivo was compared with the corresponding in vitro data. It can be concluded that a large fraction of hypoxic cells is present in these tumours and that repair takes place in vivo at least as much as under the in vitro conditions. These solid tumours were irradiated with 5 dose fractions of fast protons as reference radiation, and the probability pT of tumour destruction was determined as a function of dose. Irradiation with a spot of "plateau pions" indicated the same pT as a function of dose, but side effects in the intestinal tract increased also with dose, leading to the death of the animals. The probability for avoiding these side effects in the animals, pS, was also determined. Using both values, pT and pS, the probability for local tumour control was estimated. Irradiation with "peak pions" resulted in an RBE of about 2.5 for tumour destruction corresponding to the RBE found in vitro for the production of irreparable lethal lesions in hypoxic cells. Side effects in the mouse gut showed a RBE of 2.0, corresponding to irreparable lethal lesions in euoxic in vitro cells.

Animals↗