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Biomedical subjects

W Lehmann

Publications and source records attributed to W Lehmann.

At least 109 records · Page 6Linked to original sources
PubMed1987

Antimicrobial prophylaxis in head and neck surgery.

In this random study, 60 patients were given either cefotaxime, or ceftriaxone as a prophylactic measure in cervicofacial surgery. Each antibiotic was administered during a 48-hour period starting 1 h before the operation. Twenty-three patients underwent major cervicofacial surgery including opening of the pharynx or the buccal cavity by the cervical route. Only a single postoperative infection was observed as a result of a salivary fistula on the 2nd postoperative day. The two antibiotics have turned out to be very efficient as short-term prophylactic treatment in cervicofacial surgery. In other respects, the much longer half-life of ceftriaxone means that a single daily dose can be given. Finally, the cost of the prophylactic treatment is smaller using ceftriaxone than cefotaxime.

Adult↗
PubMed1987

[Acinar cell carcinoma of the salivary glands].

Between 1972 and 1985, eleven cases of acinic cell carcinoma were treated at the ENT clinic of the University Hospital Geneva. Eight of them were located in the parotid gland, three in minor salivary glands, two of these on the hard palate and one on the lower lip. Local recurrence occurred in four cases: two were recurrences of a parotid gland carcinoma and two of a minor salivary gland carcinoma. Three patients developed metastases, two in cervical lymph nodes and one in the lungs. Two tumours presented a very aggressive local development. Hence, the acinic cell carcinoma has a significant tendency to recur, to produce metastases, and may have an aggressive evolution. Radical treatment by surgery is necessary.

Adult↗
PubMed1986

[Chest wall moulages for radiotherapy of resected breast cancer with fast electrons: comparative tests of different materials].

Irradiation of the thoracic wall with high-speed electrons is one of the standard methods of prophylaxis and therapy of local recurrences and cutaneous metastases of an operated mammary carcinoma. The surface dose, however, is only 85% of the maximum dose, due to the depth dose curve of the electron beams with the preponderantly applied energy of 7MeV. This is a poor value, since most of all recurrences appear near to the surface and so the risk of giving an insufficient dose is involved. The dose distribution could be essentially improved by the use of moulages on the chest. These moulages were made of different materials which were tested and compared with respect to their suitability for radiotherapeutic purposes. The best materials proved to be "Urgo-Plastan" (manufacturer: Holphar, Sulzbach) and "Orthoplast" (manufacturer: Johnson & Johnson, Düsseldorf). Both materials are synthetic substances which after heating can easily be adapted to the body shape and which offer a good stability, little inconvenience for the patient and a relative easy handling. With these moulage materials, the surface dose is increased to 98% ("Urgo-Plastan") and 99% ("Orthoplast") of the maximum dose.

Breast Neoplasms↗
PubMed1986

[Face masks for radiotherapy of head and neck tumors: comparative tests of different materials].

A most precise immobilisation of the patient's head is indispensable in order to reach a high degree of exactness and reproducibility in radiotherapy of malignant head and neck tumors. Face masks made of different synthetic materials have proved to be a simple and economical solution for this problem. Based on our own experiences with "Baycast Longuettes" (manufacturing firm: Johnson & Johnson, Düsseldorf), eleven substances have been tested in the phantom (compound of plaster and synthetic resin, thermoplast, polyurethane foam, compounds of cotton and synthetic resin, and fibre glass compounds). An appropriate material was "Hexcelite" (manufacturing firm: Medimex, Hamburg), a reticulated thermoplast which after warming up can be easily adapted to the patient's face and which guarantees a very good fixation of the head. As compared to solid masks, there is only a slight superposition of the depth dose of Co-60 gamma radiation by secondary electrons from the mask material, so that an increased rate of radiogenic dermatitides is not to be expected.

Casts, Surgical↗
PubMed1985

Ribonucleotide reductase in ascites tumour cells detected by electron paramagnetic resonance spectroscopy.

Tyrosine radicals localized in the M2 subunits of ribonucleotide reductase have been detected by electron paramagnetic resonance (EPR) in ordinary ascites tumour cells. The intensity of its doublet EPR spectrum is higher in rapidly proliferating cells. Hydroxyurea, a specific inhibitor of this enzyme, decreases the concentration of the tyrosine radical. Whereas in different ascites tumours the doublet EPR spectrum dominates at g = 2.004, in solid tumours another more intense EPR spectrum from nitrosyl-hemoproteins appears. In conclusion, EPR spectroscopy can be used to monitor the content and variations of active M2 subunits of ribonucleotide reductase in intact ascites tumour cells.

Animals↗
PubMed1985

Specific neutralizing antiserum against a polypeptide growth inhibitor for mammary cells purified from bovine mammary gland.

A recently published method for purification of a new inhibitor of growth of mammary cells in vitro from bovine mammary gland has been modified to yield several hundred micrograms of inhibitor per kg of glandular tissue. The inhibitory effect exerted by this preparation to Ehrlich ascites mammary carcinoma cells fulfilled all biological criteria of specificity established earlier for preparations obtained by other means, the most important being that the inhibitory effect is abolished by the epidermal growth factor and insulin. The preparation is shown to consist mainly of a protein of 13 kDa which appears to be not glycosylated. An antiserum raised in mice against the inhibitor is demonstrated to be specific for the 13 kDa bovine mammary gland protein. Neutralization of the inhibitory activity by the specific antiserum strongly supports the view that the 13 kDa protein is indeed the carrier of inhibitory activity. First data on tissue distribution obtained with an enzyme-linked immunosorbent assay revealed a high concentration of the anti-inhibitor-antiserum-reactive antigen in bovine lactating but not in non-lactating mammary gland tissue and in milk fat globule membranes. Some reactivity was also found in bovine lung. These data are interpreted with respect to a possible physiological significance of the growth inhibitor.

Animals↗
PubMed1985

Carotid body paraganglioma with metastases.

The diagnosis of a carotid body paraganglioma with metastases led us to a critical review of the literature of 106 cases with metastasis reported between 1893 and 1980. The percentage of tumors with metastasis is in the order of 11.5% to 13%. There is no proven histological criterion from which to assert or infer their malignancy.

Aged↗
PubMed1985

[Computer tomography of tumors of the lateral and 3d ventricle].

In the diagnosis of tumours of the supratentorial ventricles, CT leaves some questions unanswered. This is true of the differential-diagnostic demarkation and the determination of the initial site of the tumour. Frequently, ventriculography cannot be renounced for an additional clearing-up of the last mentioned question.

Cerebral Ventricle Neoplasms↗
PubMed1985

[Current status of intrathecal antifibrinolytic therapy with p-aminomethylbenzoic acid (PAMBA) in subarachnoid hemorrhages].

The blood-brain barrier is barely affected by slight or moderate subarachnoidal bleeding so that the p-aminomethylbenzoic acid (PAMBA) administered systemically for antifibrinolytic therapy does not attain the continuous level necessary in the cerebrospinal fluid. Thus the antifibrinolytic agent should be applied intrathecally because this would totally inhibit fibrinolytic activity in cerebrospinal fluid containing blood and during the wound healing of ruptured aneurysmas. The improvement in wound healing reduces the occurrence of rebleeding, especially during the first 10 days, and improves conditions for successful surgical intervention.

4-Aminobenzoic Acid↗
PubMed1985

[Experience in the use of face masks for radiotherapy of head and neck tumors].

By means of positioning and fixation aids, the precision and reproducibility of irradiation fields in radiotherapy of malignant tumors of the head and neck can be considerably improved. Face masks made of different synthetic materials have proved to be a practicable solution of this problem. In our hospital we have developed and tested a simple and not expensive possibility of manufacturing the masks with "Baycast" (producer: Bayer AG Leverkusen). The material is generally well tolerated by the patients, and the head is sufficiently fixed. An increased incidence of radiogenic dermatitides is caused by the overlapping of the depth dose of the Co-60 gamma radiation due to additional secondary electrons emanating from the mask material. This effect can be partly prevented by cutting out the irradiation fields in the masks.

Cobalt Radioisotopes↗
PubMed1984

Purification of a growth inhibitor for Ehrlich ascites mammary carcinoma cells from bovine mammary gland.

A growth inhibitor for Ehrlich ascites mammary carcinoma cells in vitro has been purified from bovine mammary gland. The purification procedure involving homogenization and differential centrifugation under hypotonic conditions, ammonium sulfate precipitation, ultrafiltration, gel chromatography and preparative polyacrylamide gel electrophoresis (PAGE) yielded an inhibitor showing half-maximal inhibition of cell proliferation in concentrations of 1-3 ng protein per ml. Upon 125I labelling and analysis by SDS gel electrophoresis, most purified preparations revealed a single band of 12-14 kD, likely to be representative for the inhibitory protein. The inhibitor was shown to affect resumption of proliferation of stationary cells; however, it was inactive towards cells stimulated by incubation with medium before adding the inhibitor. The inhibitor is heat-labile, does not act by exhausting essential components of culture medium, and its action is antagonized by insulin.

Animals↗
PubMed1984

Fetal calf serum and epidermal growth factor prevent the inhibitory action of a chalone-like growth inhibitor for Ehrlich ascites mammary carcinoma cells in vitro.

A growth inhibitor for the Ehrlich ascites mammary carcinoma, purified from bovine mammary gland, is antagonized by very low concentrations of epidermal growth factor (2-16 X 10(-10) M) or fetal calf serum (0.001-0.1%). Thus, epidermal growth factor and the compounds in fetal calf serum have the same effect as earlier described for insulin and proinsulin [1-3].

Animals↗
PubMed1984

Is ribonucleotide reductase in Ehrlich ascites mammary tumour cells the target of a growth inhibitor purified from bovine mammary gland?

2'-deoxycytidine (dCyd), 2'-deoxyuridine (dUrd) and cytidine (Cyd) were found to relieve the inhibitory action by a factor, highly purified from bovine mammary gland, on the resumption of growth in vitro of stationary Ehrlich ascites mammary tumour cells. As described earlier, this effect is also achieved by insulin, proinsulin and epidermal growth factor and fetal calf serum. The effect of purine-2'-deoxyribonucleosides could not be properly assessed, because they were inhibitory themselves. Purine ribonucleosides as well as uridine and uracil were inactive. Because of the inactivity of the latter two compounds, the effect is attributed to an influence of the factor on the ribonucleotide reductase (RR) (and not on the de novo pyrimidine synthesis). The active nucleosides need not be present for the whole incubation time of 24 h; when treated for 4 h with the nucleosides, which are then removed before the addition of the factor, cells become insensitive against the latter. Again a similar effect has been described earlier for serum and insulin. The inhibitor of RR, hydroxyurea, prevents this specific effects of serum and (partially) insulin as well that of dCyd, also suggesting the involvement of RR in the factor action.

Animals↗