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Biomedical subjects

P Lindner

Publications and source records attributed to P Lindner.

At least 19 recordsLinked to original sources
PubMed1991

Collagen content in the rat urinary bladder following removal of an experimental infravesical outlet obstruction.

A partial urethral obstruction was induced in female rats. After 6 weeks, detrusor weight had increased eightfold and collagen concentration had decreased to about 40% compared to controls. Due to the weight gain, the total amount of detrusor collagen had increased more than threefold. Removal of the obstruction led to a rapid decrease in detrusor weight to 70, 34 and 30%, 2, 4 and 6 weeks postobstruction, although control levels were not reached. Collagen content decreased more slowly than detrusor weight, and for the same groups was 97, 69 and 67% of the value in the obstructed detrusor. This led to a rapid increase in detrusor collagen concentration which already 4 weeks after removal of the obstruction had increased to a level that did not significantly differ from the control value. The discrepancy between decrease in detrusor weight and in collagen content after removal of the obstruction suggests that a large proportion of the collagen synthesized during the period of outlet obstruction remained. Changes in the ratio between muscle and nonmuscle tissue were limited between control, obstructed and nonobstructed bladders. This suggests that the collagen concentration following obstruction and removal of obstruction is to a large extent due to changes in collagen concentration in the interstitial connective tissue rich in collagen.

Animals↗
PubMed1991

An interactive report generator for bone scan studies.

An interactive report generator for bone scintigraphy will be demonstrated. It comprises a controlled reporting vocabulary, an adaptive user interface, and a text generator. The controlled vocabulary represents the relevant concepts for bone scan reports: anatomical sites, scintigraphical phenomena, and diagnoses, and various attributes for these concept domains. Within the vocabulary selectional constraints are defined that restricts to meaningful combination of concepts. The interface provides intelligent views on the vocabulary, and presents only those terms that are relevant in a certain context. Through the interface the user may choose appropriate terms and combine them to complex findings. A German text generator for a restricted finding language transforms the entered data into morpho-syntactic surface structures and produces acceptable reports.

Bone and Bones↗
PubMed1990

Complexes of RecA protein in solution. A study by small angle neutron scattering.

RecA complexes on DNA and self-polymers were analysed by small-angle neutron scattering in solution. By Guinier analysis at small angles and by model analysis of a subsidiary peak at wider angles, we find that the filaments fall into two groups: the DNA complex in the presence of ATP gamma S, an open helix with pitch 95 A, a cross-sectional radius of gyration of 33 A and a mass per length of about six RecA units per turn, which corresponds to the state of active enzyme; and the compact form (bound to single-stranded DNA in the absence of ATP, or binding ATP gamma S in the absence of DNA, or just the protein on its own), a helical structure with pitch 70 A, cross-sectional radius of gyration 40 A and mass per length about five RecA units per turn, which corresponds to the conditions of inactive enzyme. The results are discussed in the perspective of unifying previous conflicting structural results obtained by electron microscopy.

Adenosine Triphosphate↗
PubMed1990

[Quantitative determination of cerebral perfusion using digital subtraction angiography (DSA)].

In a search for a reliable and relatively non-invasive method for quantifying cerebral perfusion, we examined the possible role of DSA. By using special software, it is possible to demonstrate vascular morphology and obtain functional data concerning blood flow. Regions of interest are used for obtaining time-density curves and these are evaluated by a formula designed by Meier and Zierler. Perfusion through the arterial territory in both cerebral hemispheres was correlated with the clinical symptoms of the patients and with the morphological findings. Difficulties and problems are described and discussed.

Angiography, Digital Subtraction↗
PubMed1987

[Local fibrinolytic therapy of vascular occlusions in the pelvic-leg area and the upper extremity].

Seventy-three patients with vascular occlusions in the pelvis or lower limbs and three patients with upper limb lesions were treated by local low dose fibrinolysin, with strict control of any possible bleeding tendencies. Adequate recanalisation was obtained in 56 patients (73.6%). In ten patients, the occlusion recurred while the patient was still in hospital. After four to six months, 37 of the 56 (67%) of the vessels were still patent. In 18 patients, peripheral emboli resulted in some deterioration, but in 15 of these cases this could be treated successfully by operation. The methods and indications of local fibrinolysis therapy and the problems associated with it are discussed.

Adult↗
PubMed1987

[Characterization of cerebral blood flow by determining the vascular mean transit time of brain tissue using DSA].

By using a recently developed algorithm it is possible to quantify the dynamic information of a DSA sequence of the brain. The theory of algorithm allows to calculate vascular mean transit from time density curves. The algorithm minimizes the problems of densitometry with regard to "quantitative DSA". There is a strong correlation between vascular mean transit times and cerebral blood flow values, and therefore the results for mean transit times also correspond to the results obtained for cerebral blood flow. By computerized postprocessing of DSA-images it is possible to generate functional images of the brain with a spatial resolution that had not been attainable so far. The images represent the distribution pattern of reverse vascular mean transit times. The results from 36 patients with proven stenoses of the cervical vessels are reported.

Carotid Artery Diseases↗
PubMed1986

Motilin in chronic idiopathic constipation.

The plasma motilin levels were studied in seven patients with severe long-standing idiopathic constipation before and after a fat-rich test meal. The results were compared with those of a control group consisting of 10 apparently healthy persons with normal bowel function. The constipated patients had reduced basal motilin levels and a reduced motilin release after the test meal. Motilin is known to stimulate intestinal motility by inducing interdigestive descending contractions in the stomach and small intestine. A defective motilin release may therefore play a part in the pathogenesis of idiopathic constipation.

Adult↗
PubMed1986

[Varicose veins of the lung].

Varicosity of the pulmonary veins is a rare anomaly of the pulmonary vascular system. The varices do not usually change in size over years, do not cause symptoms and need no therapy. However, raised left atrial pressure can cause increase in the diameter of pulmonary vein varices. A case of lung vein varicosity in the right middle and upper lobe associated with coarctation of the aorta and an anomalous upper-middle lobe vein was observed over a period of 10 years. Increase in left atrial pressure (aortic and relative mitral regurgitation) led to enlargement of the pulmonary veins.

Female↗
PubMed1985

[Computer tomography in diagnosis of ovarian cancer].

In 90% of all cases an ovarian tumor about 2 to 3 cm in size can be visualized computertomographically using a contrast medium. Determination of the dignity can be achieved in about 81% of all cases. Malignant tumors which are impressive as smooth-walled cysts are only recognized as such in 50% of all cases. Correct staging also occurs in 50% of all cases. An accuracy of about 90% can be expected in aftercare.

Calcinosis↗
PubMed1985

[Radiologic diagnosis of metastases in the lesser pelvis].

Reviewing the literature and summarizing our own experience, the role of various imaging modalities concerning diagnosis of metastases to lymph nodes and organs in the pelvic cavity is discussed. Especially ultrasound, CT and lymphography are compared, the importance of fine-needle-aspiration is emphasized. Possible advantages of MRI are mentioned.

Female↗
PubMed1983

Quantitative, non-invasive cerebral blood flow measurements with non-diffusible tracers using a heart-rate-dependent recirculation correction--application in carotid surgery.

A general method is described for computation of blood flow from time-activity curves using intravenous injection of the non-diffusible radio-tracer technetium pertechnetate. A technique of recirculation correction is adopted which predicts the start and end of recirculation depending on the patient's heart rate. This method allows one to clearly separate the first transit from the following recirculation. A correction for bolus dispersion of the intravenously injected tracer is also used. The evaluation of cerebral dynamic perfusion studies in 126 unselected adult patients resulted in a normal CBF of 44.5 ml/min/100 g +/- 5% and a decreased CBF of less than 40 ml/min/100 g. The presented method was also applied for flow measurement on the neck vessels. A good correlation between values obtained from these regions and the corresponding cerebral hemispheres was found. The method was also tested in 40 patients with angiographically proven neck vessel stenosis and in 15 patients before and after surgery of carotid stenosis. The results prove that the haemodynamic relevance of carotid stenosis on cerebral blood flow can be quantified. The accuracy of the method is estimated better than 5% for cerebral blood flow values and better than 15% for blood flow values gained over the neck vessel regions.

Adult↗
PubMed1979

[Acute renal failure following general and vascular surgery (author's transl)].

From 1967 to 1976 after 25851 operations for abdominal and vascular diseases acute renal failure was found in 123 cases. In 1353 patients with gastric surgery we observed acute renal failure in 33 (2,5%), after 1499 operations on the gallbladder and bileduct in 12 (0,8%) and after 725 oprations on the colon and rectum in 40 (5,5%) cases. In almost 80% renal failure was caused by septic shock, which is the reason of the high mortality rate of 88% in our patients. It should be emphasized that only prophylaxis and immediate therapy of septic complications can lower the rate of postoperative renal failure and its letal event.

Acute Kidney Injury↗
PubMed1978

Proteolysis and flash photolysis of bacteriorhodopsin in purple membrane fragments.

Pronase treatment of aqueous suspensions of purple membrane fragments from H.halobium leads to the cleavage of bacteriorhodopsin. The protein fragments remaining in the membrane after treatment with relatively small concentrations of enzyme (2% w/w) in normal daylight range in molecular weight from 20,000--21,000 daltons, indicating that cleavage occurs mainly near the extremities of the protein chain. At higher enzyme concentrations the relative amounts of protein fragments having smaller molecular weight increase. Generally, the relative loss of retinal chromophore is larger than that of protein and thus the retinal binding site seems to be located near one of the chain ends that is cleaved off by enzyme. Irradiation with white light during the time of proteolysis (at both low and high enzyme concentrations) results in extensive cleavage, so that under certain conditions no high molecular weight components can be detected in SDS-polyacrylamide gels. It, therefore, appears that parts of the bacteriorhodopsin chain become more exposed to enzyme digestion when the purple membrane is illuminated. Enzyme treated aqueous purple membrane fragment suspensions still show photocycle activity. The main consequence of proteolysis is a pronounced appearance of biphasicity in the decay of M412 and the regeneration of bR570. Simultaneously the yield of O660 is reduced. As with untreated purple membrane, the correlation between the rates of decay of M412 and regeneration of bR570 is greatest when the yield of O660 is lowest.

Bacterial Proteins↗
PubMed1977

Kinetics of permeability changes induced by electric impulses in chromaffin granules.

Electric field pulses, ranging in intensity from 20 to 50 kV/cm and in duration from 10 to 40 micronsec, caused a transient increase in the membrane permeability of chromaffin granules from the bovine adrenal medulla, that led to partial release of granule soluble constituents. This transient permeability change was long-lived, as compared to the pulse duration, and the main part of material efflux occurred after the termination of the pulse. During the latter phase the temporarily increased permeability decayed to its original value, in the absence of the electric field. This indicated that the structural perturbation induced in the membrane was transient and apparently reversible. The release event was characterized by a field-dependent permeability coefficient ranging from 2x10(-4) cm/sec at 30 kV/cm to 3x10(-3) cm/sec at 50 kV/cm. The resealing process of the membrane could be described by two relaxation times, both of which decreased with increasing field strength. Tau1 varied from about 3.0 msec at 30 kV/cm to less than 2.0 msec at 50 kV/cm, while tau2 varied from about 100 to about 40 msec in the same interval of field strength. The distribution in the degree of filling of granules that had been partially depleted by an electric field pulse indicated that the population could be considered homogeneous with respect to release.

Adrenal Medulla↗
PubMed1976

[Albumin kinetics in superior mesenteric artery shock in rats].

1. After 1-hour-tourniquet of the arteria mesenterical superior of the rat the result is a loss of intravasal fluid into the small intestine. After 2-hour-tourniquet the loss of fluid into the samll intestine can be higher than the volume of plasma circulating at the start of the experiment. During therapy with plasma substitute on base of gelatine (Haemaccel) the volume of content of the small intestine increases further. 2. After 1-hour-tourniquet the content of intravasal albumin is diminished by 26%, after 2-hour-tourniquet by 46%. Under therapy with a plasma substitute the loss of intravasal albumin increases further. 3. After 1-hour-tourniquet a transient accumulation of albumin was found in the wall of the samll intestine which was reduced after 2-hour-tourniquet. 4. The intravasal albumin is excreted in the small and the large intestine. After 1-hour-tourniquet 46% of excreted albumin was found in the small intestine after 2-hour-tourniquet 61%. It can be demonstrated, that under replacement with plasma substitute the result is mainly an "albumin dilution effect". The wall of the small intestine becomes permeable to high-molecular weight substances with an average molecular weight below 60.000. An effective therapy with the plasma substitute of the AMS-shock should, therefore, contain carrier substances with a molecular weight higher than 60.000.

Animals↗
PubMed1975

Effect of electric fields on light-scattering and fluorescence of chromaffin granules.

Electric field pulses (in the 5 to 25 kV/cm range) were found to cause a transient increase in the intensity of scattered light (wavelength equals 369 nm, scattering angle equals 90 degrees) from aqueous sucrose suspensions of chromaffin granules. Similar observations were made with the membranes of osmotically lysed chromaffin granules. Under the same experimental conditions the degree of polarization of the scattered light changed only very slightly. The fluorescence of the hydrophobic probe diphenyl-hexatriene, incorporated into the membrane of intact chromaffin granules, showed similar transient changes in the intensity. The calculated relaxation times for these changes in optical properties were approximately 150 musec for the rising phase, and approximately 1 msec for the early stage of the decay. A further relaxation time of about 30 msec was also observed by using this probe. Essentially, all of these signals originated from the granule membrane, and could be attributed to rather small changes in particle size, membrane thickness or refractive index. Moreover, these signals were found to be completely reversible. Catecholamine release from intact granules, pulsed at voltages of 25 kV/cm, occurs already during the first few milliseconds of the transient membrane change.

Animals↗