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Biomedical subjects

D Frost

Publications and source records attributed to D Frost.

At least 55 records · Page 3Linked to original sources
PubMed1985

[New possibilities in radiotherapy of endobronchial tumors using the afterloading method in combination with laser technics].

New possibilities for radiotherapy of bronchial carcinomas are provided by the combined application of the recently introduced afterloading method used hitherto in the treatment of stenosing processes of bronchial carcinomas and the neodyme-YAG laser which opens the stenosis in such a manner that the afterloading probe can be inserted. This new method allows to perform without complications or disadvantages further combined therapies such as percutaneous irradiation (telecobalt, linear accelerator or betatron). An irradiation scheme leading to a decisive tumor regression can be established due to the fast reventilation of the lung obtained by both methods. Surprisingly, three patients could be submitted despite the small-field radiotherapy to rather important lung operations such as lobectomy and pneumonectomy which were performed without complications or disadvantages. The patients were not operable without laser and afterloading therapy. This method was applied several times in the treatment of other diseases such as oesophageal cancer and stenosing cancer of the antrum. In these cases, a normal ingestion due to tumor regression was obtained rapidly.

Brachytherapy↗
PubMed1983

Photoperiod and melatonin influence seasonal gonadal cycles in the grasshopper mouse (Onychomys leucogaster).

Development of the reproductive apparatus was delayed in grasshopper mice maintained from birth in short photoperiods (10 h light/day). The inhibitory effects of short photoperiods on sexual maturation eventually waned and mice in 10L:14D became reproductively active. Adult mice transferred from long (14 h light/day) to short photoperiods underwent testicular regression after 10 weeks and complete gonadal redevelopment after 30 weeks. A similar phenomenon was observed in adult female mice; oestrous cycles ceased within 3 weeks and resumed after 13 weeks in the short photoperiod. The regressive effects of short photoperiods on the male reproductive system were mimicked by daily injections of melatonin administered to mice housed in 14L:10D. Responsiveness of the female reproductive system to melatonin was reduced among photorefractory as compared to photosensitive mice. We suggest that the initial rate of sexual maturation and the timing of seasonal breeding in adult mice are regulated by photoperiod; effects of short daylengths on the neuroendocrine-reproductive axis appear to be mediated by the pineal gland.

Animals↗
PubMed1982

Synthesis and antitumor activity of new platinum complexes.

A new type of antitumor platinum complex has been prepared and examined for antitumor activity against L1210 leukemia both in vitro and in vivo. The coordination environment of platinum in these complexes consists of three anionic chloride ions and a positively charged amine. The positive charge is introduced by monoprotonation or monoalkylation of a diamine. Platinum(IV) derivatives have been prepared for several of the complexes, and a water-soluble sulfate derivative has been prepared for one of them. Several of these complexes exhibit significant in vitro activity, and trichloro(3-aminoquinuclidinium)platinum(II) (QTP) exhibits significant in vivo activity as well. An increase in life span of approximately 40% has been observed using QTP. QTP is toxic at doses slightly in excess of effective doses.

Animals↗
PubMed1981

Aorto-coronary vein fistula. A complication of coronary artery bypass graft surgery.

We report two cases of the inadvertent insertion of a saphenous vein bypass graft into the anterior cardiac vein creating an aortocoronary vein fistula. The clinical recognition, evaluation, and management are discussed. Suggestions on surgical technique to help minimize or eliminate this potential complication during saphenous vein bypass surgery are proposed.

Aged↗
PubMed1980

Pseudo Meigs' syndrome. A case report.

The association of ascites, hydrothorax and struma ovarii has been previously reported in the literature. This case is added to the literature describing a variant of Meigs' syndrome, or pseudo Meigs' syndrome. A discussion of the origin of ascitic fluid illustrates how little is known about these conditions as well as the importance of their careful differential diagnosis.

Ascites↗
PubMed1979

[An information system for a department of nuclear medicine (author's transl)].

A computer system is connected on-line to each working place of a department for nuclear medicine. It is assisting the daily work such as the measuring and processing of the measured data, the medical interpretation of the results and the finding of the diagnosis, and finally the composing and writing of medical reports. Additionally this system supports the organization of the department in many ways. The organisation and functions of the system are described.

Berlin↗
PubMed1978

[A microcalorimeter for assessment of the G-value of a ferrous sulfate solution for high-energy electrons (author's transl)].

A microcalorimeter with constant ambient temperature has been designed (circa -195 degrees C = temperature of the absorber), which could be utilized with doses from 10 rd upward. The G-value for ferrous sulfate was assessed by means of comparison measurements with the calorimeter and a Fricke-dosimeter, using two different electron energies. The G-value at 24.8 MeV amounted to 15.64 +/- 0.14 ions/100 eV and at 38.8 MeV, to 15.60 +/- 0.13 ions/100 eV.

Calorimetry↗
PubMed1978

[Protection from X-ray radiation in the surgical room (author's transl)].

Constructional radiation protection of X-ray examination rooms is perfectly settled by DIN 6812. The present study was intended to ascertain safe handling of X-rays in the surgical room. The measuring technique with LiF-dosimeters is described, and its results concerning the load to surgical personnel are communicated. Though, with frequent operations, the monthly turn-on time does not exceed thirty hours according to DIN 6811, the maximum permissible individual dose, nevertheless, will be exceeded. A practical representation of radiation load as a function of the turn-on time will facilitate to surgical personnel the estimation of dose. Then, spatial isodoses are shown by means of which the necessary protection equivalent of the building can be calculated. Even the minimum demand for a limitation of the controlled area to the surgical room does require lead-equivalent protection if the surgical room is small.

Mathematics↗