Biomedical subjects

P M Wirtz

Publications and source records attributed to P M Wirtz.

8 recordsLinked to original sources

PubMed1991

Piezoelectric shock wave lithotripsy of salivary gland stones: an in vitro feasibility study.

The feasibility of fragmentation of salivary stones by a new extracorporeal piezoelectric lithotripter was investigated. A total of 40 salivary stones were submitted to piezoelectric shock wave treatment. The diameter, weight, and volume of all the stones were determined prior to shock wave administration. After shock wave administration the chemical composition of the stones was investigated by X-ray diffractometry. Fragmentation was achieved in 35 out of the 40 (87.5%) stones. Twenty-five of the 40 (62.5%) stones were disintegrated "therapeutically adequate" (residual fragments less than 1.5 mm). A statistically significant correlation was not observed between the number of discharges required for disintegration and the diameter, weight, volume, or the chemical composition of the stones.

Feasibility Studies↗

PubMed1990

[Adjuvant chemotherapy of breast cancer with the CMFV protocol].

Adjuvant CMFV therapy was administered from 1975 to 1984 at the Department of Gynaecology and Obstetrics of the University of Erlangen in 331 patients from a patient population, who underwent an operation with the intention of curing invasive breast cancer. Six cycles of this therapy were administered to 224 women. Only these patients were considered in the evaluation. 538 patients without axillary lymph node metastases and without adjuvant therapy served as reference population. The significance of adjuvant CMFV therapy in relation to the lymph node and menopausal status was investigated in a retrospective analysis. It was shown, that the five-year actual survivals in the group of premenopausal patients with one to three affected lymph nodes and CMFV therapy (n = 60), did not differ significantly from the group of women with premenopausally negative lymph nodes without adjuvant therapy (n = 198) (87.7% versus 88.2%). On the other hand, in the postmenopausal patients, the five-year actual survivals for the corresponding groups were 65.9% and 83.2%, respectively. The difference was significant. The results indicate, that adjuvant CMFV therapy improves the prognosis in premenopausal women, above all in cases with one to three affected lymph nodes. In the postmenopausal patients, a comparable effect could not be demonstrated in this group of patients.

Adult↗

PubMed1990

[Tissue reactions with administration of piezoelectric shock waves in lithotripsy of salivary calculi].

Before clinical application of an extracorporeal piezoelectric lithotripter to treat sialolithiasis, tissue reaction during shockwave application was examined in vitro and in experiments with animals. Application of shockwaves to human tissue in vitro showed neither macroscopic nor microscopic effects. In animal experiments, the acute experiment (16 rabbits, Chinchilla-Bastard) revealed minor bleeding in the parenchyma of the parotid gland, while the chronic experiment (14 rabbits, Chinichilla-Bastard) revealed no morphologic tissue damage to the parotid region of the rabbit, as a result of piezoelectric shockwaves. However, when the eye was placed in the shockwave focal area and the shockwaves were transmitted via the fissura orbitalis to the endocranium, brain damage could be detected morphologically. In conclusion, the authors feel that the clinical application of extracorporeal piezoelectric fragmentation of salivary stones is justified, provided that a reliable positioning of the patient and exact sonographic location of the concrement are possible.

Animals↗

PubMed1990

[Long-term study of the significance of hormone receptors as prognostic factors in breast cancer].

To check the question as to the prognostic significance of oestrogen and progesterone receptors in invasive breast cancer, the course of the disease was registered in 660 patients in the context of a retrospective study. These patients had been operated on with the objective of curing breast cancer between 1976 and 1984. A receptor analysis of these patients is available with regard to both receptor types. Positive progesterone receptors could be detected in 38%, positive oestrogen receptors in 70%. Values over 15 fmol/mg tissue protein were rated as positive. The proportion of oestrogen-receptor-positive tumours increased with the age of the patients. On the other hand, the progesterone receptor did not show this dependence. During analysis of the median receptor concentrations as well as of the progesterone combinations, a correlation between the axillary lymph node status and the hormone receptor status of the primary tumour could not be observed for the two receptor types. The survival time in relation to the oestrogen receptor status did not indicate any significant effect on survival time. On the other hand, the improvement of survival time depending on the positive progesterone receptor status was highly significant in statistical terms (p less than 0.001) especially in nodal-positive patients. Both patients with axillary lymph node metastases and positive progesterone status, compared with patients without lymph node invasion and a negative progesterone status, had the same survival rate.

Adult↗

PubMed1990

[Morphometric analysis of age-dependent changes of the human ciliary body].

Morphometric and stereologic techniques have been applied to human ciliary epithelium and bordering stroma of 31 (respectively 16) normal donor eyes aged 15 to 86, providing quantitative information on the age-related structural changes of ciliary body tissue. Aging appeared to result in a generalized widening of the stromal layer from 19.3 +/- 2.4 microns (10-20 years; n = 4) to 60.0 +/- 11.5 microns (80-90 years; n = 3) in ciliary processes and from 53.0 +/- 6.8 microns to 107.6 +/- 15.2 microns in the ground plate between ciliary valleys and ciliary muscle, a density increase of collagenous fibers from 39.3 +/- 4.9 to 83.5 +/- 14.6 fibers/microns 2 and a concomitant decrease in mean fiber diameter from 62.8 +/- 3.4 nm to 55.7 +/- 1.5 nm, a decline of stromal cell density from 31.4 +/- 1.8 to 9.6 +/- 1.0 cells/0.014 mm2, a progressive thickening of the inner and outer limiting membranes from 0.8 +/- 0.4 micron to 8.1 +/- 1.5 microns and 2.1 +/- 0.6 microns to 4.5 +/- 0.5 microns respectively as well as the endothelial basement membrane from 0.13 +/- 0.004 micron to 0.25 +/- 0.03 micron, a gradual widening of the perivascular space between capillaries and overlying pigment epithelium from 6.2 +/- 1.5 microns to 11.3 +/- 2.9 microns, an increase in number of fenestrations in the capillary endothelium from 39.0 +/- 8.5 to 69.0 +/- 7.0 pores/100 microns, and finally a continuous augmentation of degenerative elements including lipids, lipofuscin granules, and lysosomes from 1.5 +/- 0.06% to 7.2 +/- 0.6% within the non-pigmented epithelium (NPE) over the 71-year period studied. Regression analysis yielded a highly significant impact of age on these morphometric parameters, while the relative volumes of the remaining cell compartments of the NPE-cells revealed no statistically significant correlation with age. Rather, the variations in volume densities of Golgi bodies (0.34 +/- 0.25%; n = 16) and pigment granules (0.36 +/- 0.27%; n = 16) seemed to be random with respect to age, whereas the relative volumes of mitochondria (21.7 +/- 1.8%; n = 16) and RER (5.9 +/- 0.7%; n = 16) remained fairly constant indicating that the NPE-cells maintain their functional capacity with advancing age. Age-related reduction of aqueous humor formation therefore appears to be rather due to impaired fluid passage from vasculature to ciliary epithelium than to functional incompetency of the NPE.

Adolescent↗

PubMed1990

Desmosomal-mitochondrial complexes in human nonpigmented ciliary and retinal pigment epithelia.

In the normal human nonpigmented ciliary epithelium structural associations between mitochondria and desmosomes are described electron-microscopically: either a single desmosome or a linear array of several desmosomes joined by filamentous bundles is associated with one or two mitochondria (19.6 +/- 5.4%; n = 29). The frequency of occurrence of these complexes was studied in five different regions of the ciliary body; analysis of covariance revealed a significantly increased number of associations in the ciliary processes. Further, the age dependence of their occurrence was examined in 29 different age classes (15 to 86 years); correlation analysis revealed no correlation between age and number of associations. Similar complexes occur, in addition, in the retinal pigment epithelium, but have not been observed in ciliary pigmented, lens, iris and corneal epithelia. Desmosomal-mitochondrial complexes are considered to be a characteristic feature of basic physiological significance of certain epithelia only. The cytochemical demonstration of calcium in the associated mitochondria provides support for the hypothesis that the mitochondria may serve as buffers for intracellular calcium by controlling the local calcium concentration, thus increasing the stability and functional integrity of desmosomal junctions in secretory or actively transporting epithelia with high endogenous calcium levels.

Ciliary Body↗

PubMed1989

[Diurnal differences in alcohol absorption].

Under standardized conditions five subjects were submitted twice to a dose of alcohol of 1.1 g/kg. This dose was administered once between 7:15 and 7:45 am. and at a different day between 7:15 and 7:45 pm. The blood alcohol concentration curves in the morning and the evening differed significantly in peak and time elapsed until this value was reached. During the morning the peak averaged 32% higher than in the evening. In the morning it was reached after about 60 min and during evening after 110 min. The elimination rate was about the same. These results show that alcohol is significantly faster absorbed into the blood in the morning than during the evening. This could be explained by accelerated transport of uptaken alcohol into the bowels.

Adult↗

PubMed1989

[Extracorporeal piezoelectric lithotripsy of salivary calculi. In vitro studies].

The feasibility of fragmentation of salivary stones by a new extracorporeal piezoelectric lithotripter was investigated. A total of 40 salivary stones were submitted to piezoelectric shockwave treatment. Prior to shockwave application the diameter, weight and volume of all the stones were determined. After shockwave application the chemical composition of the stones was investigated by X-ray diffractometry. Fragmentation was achieved in 35 of 40 (87.5%) stones. Of these 40 stones, 25 (62.5%) were disintegrated adequately (residual fragments less than 1.5 mm). No statistically significant correlation was observed between the number of discharges required for disintegration and the diameter, weight, volume or the chemical composition of the stones.

Humans↗