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Biomedical subjects

H Wirth

Publications and source records attributed to H Wirth.

At least 73 records · Page 4Linked to original sources
PubMed1978

The effect of systemic treatment with 5-fluorouracil on the epidermis of the guinea pig.

The thymidine labelling index and the mitosis rate (blocked by colcemid) in the basal cell layer of the guinea pig were determined before and during treatment with 5-fluorouracil (1 mg i.p. in 2 day's interval/100 g body weight). Additionally, the epidermal area and thickness and the number and size of cells were measured. 5-Fluorouracil equally reduces the thymidine labelling index and the mitosis rate with the full effect after treatment of at least 22 days. From these findings it is concluded that the S-phase--calculated from the end of the thymidine synthesis--is not altered. Furthermore atrophy of the epidermis runs parallel with the reduction of the 3H thymidine labelling index and the mitosis rate.

Animals↗
PubMed1978

The effect of systemic treatment with 5-fluorouracil on the epidermis of the guinea pig.

The thymidine labelling index and the mitosis rate (blocked by colcemid) in the basal cell layer of the guinea pig were determined before and during treatment with 5-fluorouracil (1 mg i.p. in 2 day's interval/100 g body weight). Additionally, the epidermal area and thickness and the number and size of cells were measured. 5-Fluorouracil equally reduces the thymidine labelling index and the mitosis rate with the full effect after treatment of at least 22 days. From these findings it is concluded that the S-phase--calculated from the end of the thymidine synthesis--is not altered. Furthermore atrophy of the epidermis runs parallel with the reduction of the 3H thymidine labelling index and the mitosis rate.

Animals↗
PubMed1977

Changes in blood flow and vasculature of the dog kidney undergoing normothermic and hypothermic ischaemia.

In 11 mongrel dogs both kidneys have been subjected to a 2 h ischaemic period. One kidney was cooled by perfusing the renal artery at 4 degrees C while the contralateral normothermic kidney was clamped for 2 h. Studying the renal blood flow using the Xenon wash out technique, sequential renal scanning and angiography, marked differences between hypo- and normothermic ischaemia kidneys were observed. One or two hours following hypothermic perfusion a marked decrease of blood flow in the first compartment and vasoconstriction was evident, while within this period following normothermic ischaemia an enhanced renal blood flow was observed. After 24 h renal blood flow and renal function tested by 131I-Hippuran clearance returned to normal values. Angiographic studies corresponding to the preoperative findings. In contrast, normothermic ischaemia kidneys showed a decreased renal blood flow, impairment of kidney function in isotope studies and pathological angiographic changes.

Animals↗
PubMed1977

Free-flow electrophoresis. III. An analytical version for a rapid, quantitative determination of electrophoretic parameters.

An analytical device based on the principle of free-flow electrophoresis is described. Electrophoretic mobility distributions of proteins or cells can be obtained quickly with field-strengths of about 140 V/cm. Up to 100 samples can be tested per hour. The accuracy and reproducibility of the device is illustrated by the example of the serum protein separation. Quantities in the picomole range can be quantitatively evaluated. In the course of mobility measurements of cells and cell mixtures, a reproducibility of +/- 1.4% was obtained. Therefore this device meets both the needs of electrokinetic research and the requirement of routine measurements in clinical diagnosis. Finally, the application of a pH gradient is described and the limitation due to methodical aspects is shown.

Animals↗
PubMed1976

Analysis of velocity sedimentation techniques in cell separation. Influence of apparative and sample properties on separative power, resolution and sensitivity.

In the present investigation the velocity sedimentation technique was analysed with respect to separation resolution, power and sensitivity. It was found that apparative modifications do not influence the resolution, which is a function of the contribution of apparative errors to the dispersion. A surprisingly small parameter of 0.15 was determined and it seems unlikely that this value can be improved. On the other hand an apparative modification is presented which improves the separation power and makes sample loading independent of the gradient filling. If cells (from rat bone marrow) were separated, a several times higher dispersion for a given cell volume was observed than was due to the apparative error. It was concluded that density variations were the major source of this dispersion. Since cell volume and density apparently show independent variations within a biological cell population the cell density cannot be disregarded if velocity sedimentation profiles are discussed in physical terms as is often done.

Cell Separation↗
PubMed1976

[Changes in perfusion and blood flow distribution following normo- and hypothermic ischemia of the kidneys].

Experimental examinations were performed in 22 dogs to find out the mechanism which leads to a permanent or a reversible damage of the renal parenchyma after normo- and hypothermic ischemia. For this reason the perfusion and the distribution were examined with 133Xe, the vascular changes by angiography, and the parenchymal function with 131I-Hippuran. After normothermic ischemia a short-term reactive hyperemia appeared, which however could not compensate the damage of the renal tubular cells and the resulting excretory insufficiency. After hypothermic ischemia the perfusion was reduced, probably as a consequence of a vasconstriction by cold, however, the function of the tubular cells remained intact, because of the protective mechanism of the hypothermia. The importance of these findings for the development of the so-called "shock-kidney" (acute tubular necrosis) and for the conservative renal surgery in hypothermia is discussed and the application of measures beneficial to perfusion, are suggested.

Animals↗
PubMed1975

[Free-flow electrophoresis. I. Theoretical and experimental investigations of the influence of mechanical and electrokinetic variables on the efficiency of the method].

In the present paper, various types of band-broadening effects in free-flow electrophoresis were investigated. They resulted from the velocity profiles of the liquid curtain and electroosmosis, temperature gradient, thermal diffusion and sample inlet geometry. An analytical free-flow electrophoresis apparatus permitted easy observation of these parameters. The experiments showed that the influence of the temperature gradient was negligible, whereas the effect of the velocity profiles on band broadening was higher than theoretically expected. In preparative work this is of utmost importance, since overlap of bands is not desirable. In this case, the zeta potential of the walls can be adjusted to that of the material to be separated, resulting in a considerable reduction of band broadening. Various approaches are indicated. Further attention was given to the influence of the relaxation effect on the separation. Conditions are shown where particles are separated either according to their surface charge density or to their size. The practical relevance of the results is discussed.

Electrophoresis↗
PubMed1975

[A dangerous perforating injury of the soft palate in childhood (author's transl)].

Perforating injuries of the soft palate in childhood are generally uncomplicated. Such simple injuries may however be accompanied by far reaching consequences. A resulting thrombosis of the A. carotis interna in a child after a perforating injury of the soft palate showed how difficult diagnosis may be. Perforating injuries of this type are relatively common, complications are relatively rare. Furthermore the injury may be followed by a lengthy symptom-free interval. No further diagnostic procedure seems necessary during this interval than clinical examination. The belated appearance of central symptoms comes at a time where all to often diagnosis and therapy can not influence the final outcome.

Carotid Artery Thrombosis↗