Biomedical subjects

H Heynemann

Publications and source records attributed to H Heynemann.

At least 37 records · Page 2Linked to original sources

PubMed1999

Differential expression of heat shock proteins 70-1 and 70-2 mRNA after ischemia-reperfusion injury of rat kidney.

Ischemia-reperfusion injury in the kidney is known to cause induction of the inducible form of the 70 kDa heat shock protein HSP70i (or HSP72). However, knowledge of the expressional regulation of the two coding genes for HSP70i - HSP70-1 gene and HSP70-2 gene - is very limited. We investigated the time course of HSP70-1 and -2 mRNA expression and its relation to cellular ATP levels in the renal cortex after different periods of unilateral warm renal ischemia (10-60 min) and reperfusion (up to 60 min) in 10-week-old male Wistar rats. Immediately after ischemia there was a significant induction of both HSP70i genes. While HSP70-1 expression constantly increased (up to 4-fold) during reperfusion, even to a higher extent with prolongation of ischemia, HSP70-2 mRNA - which was generally expressed at a far lower level than HSP70-1 mRNA - was strongly induced (3-fold) during reperfusion only after brief periods (10 min) of ischemia. Cellular ATP levels rapidly dropped to 5% with ischemia and the pattern of recovery during reperfusion significantly depended on the duration of the ischemic period, thus showing a good relation with the heat shock (protein) gene expression. We conclude that HSP70-2 is the more sensitive gene with a lower activation threshold by mild injury, while the HSP70-1 gene mediates the major response of heat shock protein induction after severe injury.

Adenosine Triphosphate↗

PubMed1998

[Equipment-independent ultrasound tissue characterization of testis and prostate].

The result of a B-scan ultrasound examination is strongly dependent on the type of the used B-system, the chosen system parameters and the experience and critical analysis of the clinical investigator. The estimation of quantitative acoustic parameters, independent of the type of the used B-system, is one way to overcome the subjective nature and the problems of the interpretation of B-scan images. A procedure was developed to determine acoustical tissue specific parameters (ultrasound attenuation, relative backscatter coefficient) in terms of the ultrasound spectroscopy and to correct the system effects. A requirement for the calculation of acoustical parameters is the availability of primary rf echo signals without any preprocessing. Up to now measurements of phantom materials and in-vivo investigations on human testis and prostate have been carried out. The effects of pathological changes in the tissue state on the acoustical parameters are demonstrated in some examples.

Artifacts↗

PubMed1998

Endopeptidase 24.11/CD10 is down-regulated in renal cell cancer.

The regulatory mechanisms responsible for malignant transformation, tumor progression and metastasis in renal cell cancer (RCC) are still unclear, but there is some evidence that biologically active peptides might have regulatory effects on the behavior of this malignancy. Tumor cells can change local concentrations of active peptides by modulating their cell-surface enzymes. Using immunohistochemistry and enzyme-histochemistry, the expression of various membrane peptidases was examined in RCC and adjacent noninvaded renal parenchyma (n = 44). We describe the down-regulation of neutral endopeptidase 24.11 (NEP) protein expression in RCC of the clear cell/chromophilic type when compared with renal parenchyma, and show for the first time the lack of enzyme activity of NEP in RCC. The strongest expression could be found for dipeptidyl peptidase IV (DPIV) which is only decreased in RCC of the chromophobe cell type and is even present in oncocytoma. Aminopeptidase N (APN) and aminopeptidase A (APA) show attenuated expression in up to one third of clear cell/ chromophilic RCC. Chromophobe RCC and oncocytomas do not express APN, APA, NEP and gamma-glutamyltranspeptidase.

Adenoma, Oxyphilic↗

PubMed1996

Prognostic value of the immunomonitoring of patients with renal cell carcinoma under therapy with IL-2/IFN-alpha-2 in combination with 5-FU.

After tumor nephrectomy, patients suffering from metastatic renal cell carcinoma (RCC) received interleukin-2 (IL-2), interferon (IFN)-alpha-2b and 5-fluorouracil (5-FU) in one to three treatment cycles over 8 weeks. Using flow cytometry, we investigated the immunophenotype of peripheral blood lymphocytes from 22 patients during therapy. In all patients, we found an increase in the absolute number of T lymphocytes, especially of the CD4 type, and in the number of HLA-DR+, CD25+ T cells and natural killer (NK) cells. The mean number of B cells did not increase during therapy. The numbers of CD4+, CD8+ and CD25+ T cells correlated significantly with the clinical response. In addition, we found that the pretherapeutic number of T lymphocytes and B cells but not of NK cells was significantly higher in patients with a therapy-induced clinical response. In conclusion, we describe the predictive value of the number of lymphocytes from peripheral blood for the efficiency of IL-2/IFN-alpha-2b therapy in combination with 5-FU in patients with metastatic renal cell carcinoma.

Adult↗

PubMed1992

[Sonographic evaluation of changes in testicular tissue by ultrasound spectroscopy].

Experimental investigations were carried out under in vitro conditions on 25 normal human testicular specimens and on 60 pathological testicular specimens to ascertain the ultrasound attenuation using an ultrasound spectroscopic measuring technique. The ultrasound attenuation was established by calculating the ultrasound attenuation coefficient alpha. The average values of ultrasound attenuation (alpha) in normal testicular tissue were distinctly lower than in pathologically altered testicular specimens. A comparison of the various pathologically altered testes showed higher attenuation in the case of malignant neoplasms whilst the highest average values of wore recorded for non-neoplastic pathological alterations in the testicular tissue. The results of the investigations show that certain alterations in the tissue can be ascertained by ultrasound spectroscopy. The analysis of further acoustic parameters in future investigations, such as ultrasound back-scattering and velocity, along with the recording of ultrasound attenuation, gives scope for improved assessment of the tissue. Thus ultrasound spectroscopy increases the sonographic accuracy acquired through analysis and the weighing up of symptoms of tissue dependent ultrasound parameters.

Adolescent↗

PubMed1990

[The improvement of the tolerance of the kidney for ischemia with the prostacyclin analog iloprost].

Operative trauma, ischemia, release of catecholamines and thermal stimuli in consequence of harvesting, preservation and transplantation deteriorate the renal capillary circulation. By crossing of tolerance limits arises an irreversible transplant damage. The conditions of our examinations were placed in this field. By pre- and postischemic application of Iloprost was demonstrable an improvement of the ischemic tolerance of the kidney. Correction of renal hemodynamics, antiplatelet action and cytoprotection are the reasons of the protective influence of Iloprost in our opinion.

Acute Kidney Injury↗

PubMed1990

[Effect of the stable prostacyclin analog Iloprost on enzyme release during extracorporeal kidney perfusion].

The influence of the stable prostacyclin-analogue Iloprost (Fa. Schering, Berlin) in the enzyme release from extracorporalic perfused kidneys was tested in an experimental investigation. The mechanic hypothermic perfusion was carried out on four different conditions. The estimation of specially cytosolic, lysosomal, and membrane-associated enzymes in the perfusat of the kidneys showed less activities in the Iloprost-protected kidneys. The results after the replantation of the kidneys support the interpretation of the enzyme determinations.

Acid Phosphatase↗

PubMed1990

[Experimental studies of the effect of fixation time on ultrasound extinction in formalin-fixed testicular tissue].

The influence of fixation time on the ultrasound damping was investigated in vitro in both normal and altered formalin-fixed testicular tissue. By means of ultrasound spectroscopy the ultrasound damping coefficient alpha is estimated. The results of measurements in different time intervals after onset of fixation did show that in both normal and altered testicular tissue only slight changes of ultrasound damping was found. Therefore, the influence of fixation time could be neglected.

Fixatives↗

PubMed1990

[Effect of various fixation agents on ultrasound damping in normal and pathological testicular tissues].

In normal and pathological testicular tissue the influence of various fixing agents (Formalin solution, Bouins solution, Hellys solution, Carnoys solution) concerning the acoustical properties of testicular tissue was examined. By means of an ultrasound spectroscopic measurement technique the ultrasound damping was registered by calculation of the ultrasound damping coefficient alpha. The results show that the most lower alpha values were obtained by fixation with formalin solution as well in normal as in altered testicular tissue. The results of fixation according to Helly, Carnoy and Bouin did show markedly differences. Therefore, the fixation of testicular tissue using formalin solution is the best way for experimental examinations of the ultrasound damping behaviour.

Dysgerminoma↗

PubMed1990

[Influence of examining temperature on the ultrasound attenuation in testicular tissue].

By means of an ultrasound spectroscopic measurement technique the influence of examining temperature on the ultrasound attenuation was experimentally investigated on formalin-fixed normal and altered testicular tissue. In the examined tissue specimens a temperature-dependent change of ultrasound attenuation (alpha on 6 MHz) was found in the temperature area between 10 and 50 degrees C. In the altered testicular tissue a higher damping decline could be observed. On the measuring points the specimens were examined by light microscopy.

Dysgerminoma↗

PubMed1990

[Experimental investigations on the effect of the transducer-specimen distance on the ultrasound attenuation of formalin-fixed testicular tissue].

Additional information on the tissue structure are possible by estimation of sound physical parameters in comparison with normal B-scan ultrasonography, especially the frequency-dependent ultrasound attenuation. The ultrasound attenuation measurements were made on histochemical normal and pathological testicular tissue with changing transducer-specimen distance. No markedly difference in damaging behaviour was found between normal and pathological testicular tissue at different distances.

Fixatives↗

PubMed1989

[Ultrasound attenuation as a function of frequency in formalin fixed testicular tissue].

Measurements of the ultrasound attenuation were carried out in 10 normal testes and 20 pathologically changed testicular tissue biopsies in vitro after formalin fixation. The ultrasound attenuation as function of the frequency was recorded ultrasound-spectroscopically about the complete frequency spectrum of the ultrasound-broad range transformer (3-8 MHz). The frequency dependence of the attenuation behaviour differed in the 10 normal testes from the 20 pathologically changed biopsies by smaller values of the ultrasound attenuation coefficient a (linear regression analysis). The ultrasound attenuation in a characteristic measuring point allows the differentiation between normal and pathologically changed testicular tissue. The following comparison with the histologic evidences showed the correspondence of the results.

Adolescent↗

PubMed1987

[Effect of Iloprost (ZK 36 374) on hemodynamic parameters during kidney donor conditioning in animal experiments].

Hemodynamic parameters during the conditioning of kidney donors were tested under the influence of Iloprost (ZK 36 374), a stable prostacyclin derivate, in 12 house swine of a body weight of 20-50 kg. The electromagnetically measured blood flow in the right renal artery increased on an average of 73.2% after intraaortic infusion of Iloprost (1 micrograms/kg.min) during 15 minutes. The mean arterial blood pressure decreased simultaneously by 14.7%. The renal flow resistance (RVR), by blood pressure and blood flow calculated, decreased by 49.7% in average. Iloprost appears well-suitable for conditioning donors, it shows advantages in contrast to the hitherto used drugs.

Animals↗

PubMed1986

Improvement in the preservation of ischemically impaired renal transplants of pigs by iloprost (ZK 36 374).

Kidneys of five pigs were preoperatively perfused with iloprost in situ (infusion of 0.5 microgram X kg-1 for 15 minutes) and exposed to a warm ischemic period of 45 minutes. The behaviour of these kidneys during initial perfusion by gravity and hypothermic mechanical perfusion for 24 hours was comparable to that of kidneys having had a warm ischemic period of less than 5 minutes. After retransplantation all kidneys showed a sufficient blood flow and immediate production of urine during the test period of 3 hours.

Animals↗

PubMed1986

[Hemodynamic studies of iloprost-conditioned ischemically stressed kidneys in animal experiments].

By means of computer-assisted Doppler signal analysis on the exposed renal artery of the pig the change of the haemodynamics under the influence of Iloprost is investigated in comparison to the electromagnetic flow measurement. The Doppler sonographic establishment of the speed of the blood flow and the relative volume of the blood flow allows additional informations about characteristic changes of the form of the pulse. During the measurement in situ on the renal artery the result was during the intraarterial application of Iloprost a distinct increase of the renal blood flow with simultaneous decrease of the renal resistance, which, issuing from the Doppler signal analysis, is characterized as change of the renal resistance index. The kidneys conditioned under influence of Iloprost were retransplanted after a warm ischaemia-time of 45 minutes with following machine preservation of 24 hours and showed a stable flow characteristics for the whole investigation period. The Doppler signals directly conducted via the renal parenchyma showed a stable pulsation also in the smaller arterial vessels.

Animals↗

PubMed1986

[Effect of iloprost on aggregation behavior in kidney conditioning and changes in iloprost concentration in kidney preservation].

The conditioning of the donor by 1.0 microgram/kg X min Iloprost over 15 minutes leads to a considerable inhibition of the aggregation of thrombocytes in the domestic pig. 160% more ADP had to be added than before the application of Iloprost. When 0.5 microgram/ml Iloprost are added to the perfusion fluid and to the reperfusion fluid 0.22 microgram/ml and 0.27 microgram/ml, respectively, are to be proved in the venous efflux. Whether or not the difference is absorbed or metabolized must remain open. During the 72-hour storage of the kidney in a Euro-Collins-solution with 0.5 microgram/ml Iloprost after 24 hours a decrease of 0.34 microgram/ml, after 48 hours to 0.33 microgram/ml and after 72 hours to 0.20 microgram/ml takes place. Thus Iloprost is present in an effective concentration also after 72 hours. The decrease to one plateau rather speaks for a consumption by active metabolic effect or absorption than for a chemical decomposition.

Animals↗

PubMed1985

[Effect of the stable prostacyclin analog (iloprost) on survival of ischemically-stressed swine kidney transplants].

Kidneys of 5 pigs were pretreated in situ with Iloprost (Fa. Schering) (0.5 micrograms X kg-1 X min-1) and exposed to a warm ischaemia time of 45 minutes. The perfusion behaviour of these kidneys during the initial fall current perfusion and hypothermic machine perfusion for 24 hours was to be compared with that of kidneys with a warm ischaemia time of less than 5 minutes. After retransplantation in all kidneys a good blood supply and an immediate urine production was to be seen for the duration of the experiment of 3 hours.

Animals↗

PubMed1985

[Extended storage preservation of swine kidneys to 72 hours using iloprost].

The intraaortal infusion of Iloprost (1 micrograms/kg X min) for the duration of 15 minutes leads to an increase of the renal hematorrhea by 85.2%, to a decrease of the renal resistance by 51.6% and to a slight decrease of the average arterial blood pressure by 13.3%. After a 72-hour hypothermic storage preservation under addition of Iloprost the renal blood supply after retransplantation corresponded to the initial values of the blood flow before nephrectomy. The production of urine began after 1-2 minutes. Enzyme investigations of the transplant urine resulted in an increased excretion of the cytosolic enzymes, the structure-bound enzymes, however, remained in the area of the norm. The investigation of the electrolytes of the urine showed a hypersodiuria as well as a hypopotassiuria and calciuria. As to urea and creatinine the values were below the parameters used for comparison. In the contralateral kidneys used as control kidneys no blood supply developed after retransplantation. The application of Iloprost for the conditioning of donor kidneys is very well suited and shows some advantages compared with the preparation used up to now. The prolongation of the hypothermic storage preservation to 72 hours seems to be possible by the application of Iloprost.

Animals↗