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K H Albrecht

Publications and source records attributed to K H Albrecht.

At least 37 records · Page 2Linked to original sources
PubMed1994

[The value of duplex sonography after orthotopic liver transplantation. Experience with 44 patients].

In a prospective study, 44 patients (11 women, 33 men) who had received orthotopic liver transplants underwent a total of 196 consecutive duplex Doppler ultrasound examinations. The aim of the study was to evaluate the correlation between the pulsatile flow index (PFI) and the damping index (DI) as far as complications as rejection or cholangitis were concerned. The patients were examined five times each on average. The PFI and DI were measured in the hepatic artery, the portal vein and the hepatic veins. The findings were compared with the clinical course (cholangitis, rejection) and the histomorphological diagnosis as determined in biopsy specimens. In biopsy-proven rejection episodes, the sensitivity of the PFI in the hepatic artery was 69.4%, the specificity 72.2%. The sensitivity of the DI in the hepatic vein was 89.4%, the specificity 89.1%. Combining the two, specificity was more than 90%. PFI and DI in the portal vein bore no apparent relation to clinical course or histomorphological diagnosis. We found duplex Doppler ultrasound extremely beneficial in determining the timing and indication for liver biopsy. In addition, this simple examination, which can be performed as often as desired, accurately shows the transplanted liver's response to measures taken to counter rejection.

Adult↗
PubMed1992

[De novo malignant tumors during drug immunosuppression. The findings following 1245 cadaveric kidney transplants in 1080 patients].

Thirty new malignant tumours were found in 1080 patients (634 men, 446 women; mean age 37.6 +/- 13.6 years) after a median follow-up period of 5 years following 1245 cadaveric kidney transplantations performed between 1972 and 1990. The mean dialysis period before transplantation had been 4.0 +/- 3.1 years. Regarding the type of tumour, carcinomas were by far the most frequent, while there was only one lymphoma. The annual malignancy incidence for renal transplant patients was 0.5%. This is 3.5 times higher for men and 4.2 times for women than in the normal population. Immunosuppression with azathioprine and/or antithymocytic globulin (n = 395) produced the same malignancy incidence (0.54%) as with cyclosporin (n = 685; 0.60%). On the other hand, malignant tumours occurred much earlier under cyclosporin than under azathioprine/antithymocytic globulin (27 and 68 months, respectively).

Age Factors↗
PubMed1992

[Progress in kidney transplantation].

The introduction of immunosuppression with cyclosporine A in 1983 compared to conventional immunosuppression has clearly improved early results within the first year post transplant. In contrast, the rate of graft failure per year in the following course has not changed essentially. Still HLA histocompatibility is a predominant prognostic factor which can be influenced by organ sharing. On the other hand, donor factors like sex and age are becoming more important and should be taken into account for organ allocation. This furthermore requires strict attention to future exchange rules within the transplant community.

Adult↗
PubMed1990

[The pulsatile flow index (PFI) in the diagnosis of dysfunctional kidney transplants].

In 61 patients (167 examinations) the pulsatile flow index (PFI) was used to diagnose the cause of renal transplant dysfunction. The results were correlated with histology and clinical course and outcome, angiography or quantitative radionuclide renography. Renal transplant rejection was diagnosed by PFI with a sensitivity of 85%. The specificity was 81% and the diagnostic accuracy 83%. The positive predictive value was found to be 76%, whereas the negative predictive value was 89%. In presence of acute tubular necrosis (ATN) the PFI was normal in 89% of examinations and therefore distinguishable from acute rejection.

Adolescent↗
PubMed1984

[Animal experiment studies of embolia cutis medicamentosa].

Embolia cutis medicamentosa (ECM) is a rare complication after intramuscular injection of certain drugs, resulting in local necrosis of skin and muscle at the injection site. The pathogenesis is still not clear. Drugs and their effective substances, from which an ECM recently was described (depot penicilline, antirheumatic drug combinations), were injected intraarterially, periarterially, and intramuscularly into the hind legs of rats. The legs were examined macroscopically and histologically. Complete skin and muscle necrosis of the hind leg was only found after intraarterial injection of the incriminated drugs. The most important single effective substance was phenylbutazone. From the experiments it is concluded that the intraarterial injection mode is the most likely pathomechanism of lokal skin and muscle necrosis in the ECM arising from the incriminated drugs.

Animals↗
PubMed1980

Motion, deformation, and interaction of blood cells and plasma during flow through narrow capillary tubes.

The microrheological characteristics of human blood cell suspensions flowing through very narrow glass capillaries (I.D. 5-12 microns) have been investigated using a traveling capillary method. In addition, red cell shape during flow was studied after cell fixation during capillary passage. The observations and measurements indicate the following: 1. The deformed shape of human red cells is not axisymmetrical and develops from an edge-on-oriented biconcave disc shape. 2. Red cells tend to travel in groups rather than equally spaced, presumably due to interindividual differences in size, shape, and deformability. 3. Red cell rotation in 8-12 microns capillaries occurs only if the flow forces are too small to induce cell deformation; during rotation of biconcave discs a substantial fraction of orbiting times is spent in an edge-on orientation; rotation is more frequently observed if the deformability of the erythrocytes is reduced. 4. Hematocrit-dependent transition from single-file to multi-file ('zipper') flow is observed in tubes whose inner diameter exceeds approximately 6 microns. 5. The flow pattern in the larger capillaries (8-12 microns) is characterized by significant variation of both radial and axial velocity of individual cells, as well as by concomitant changes of cell shape. However, cell-to-cell interactions and changes of cell orientation become progressively less significant in even smaller capillary tubes. 6. The bolus motion of intercellular plasma can be demonstrated by using microspheres or single platelets flowing between red cells as indicators. 7. Single platelets flowing between erythrocytes exhibit considerable variation in axial velocity in addition to rapid rotation.

Blood Flow Velocity↗
PubMed1979

Model experiments on the effect of bifurcations on capillary blood flow and oxygen transport.

O2-delivery by a single capillary is a function of the flow rate and the fraction of flow made up of red blood cells. Capillary flow rate in turn depends upon flow resistance which is determined by the fraction of capillary volume occupied by red blood cells. Experiments were carried out to study the relationship between these parameters in an in vitro model consisting of glass capillaries (I.D. 3.3--11.0 micrometer) branching from a large bore feeding channel which was perfused at variable flow rates with suspensions of human red cells with different hematocrits. Capillary flow rates ranged from 0--10(-4) mm3s-1. The results indicate that the red cell flow fraction increases with increasing capillary flow rate and with decreasing feeding vessel flow rate. Capillary volume fraction occupied by red cells similarly depends on these two parameters, but is consistently lower than the red cell flow fraction. Capillary flow resistance increases with flow rate due to increasing volume fraction of cells. If the results obtained with the model system are applicable to in vivo capillaries it must be concluded that O2-delivery by a single capillary is not linearly related to flow rate but increases more than proportionately with flow rate. Due to alteration of resistance with flow rate another type of "autoregulation" of capillary flow is proposed which tends to keep flow rate constant despite changes of driving pressure.

Blood Flow Velocity↗
PubMed1979

Optimal hematocrit for canine skeletal muscle during rhythmic isotonic exercise.

Contractile power, blood flow, O2-uptake, and O2-extraction during isotonic, rhythmic exercise were determined in the isolated canine gastrocnemius muscle during perfusion with blood with hematocrits between 0.21 and 0.81. The results obtained in 36 measurements on nine muscles showed that maximal O2-delivery to the muscle if found at hematocrits between 0.5 and 0.6. Both in the range of hemodilution, and in the range of extreme hemoconcentration, O2-delivery decreases significantly. O2-consumption and contractile power of the muscles are almost unaffected in the hematocrit range between 0.4 and 0.7; beyond and below this hematocrit range both parameters decrease. O2-extraction is virtually constant in the hematocrit range between 0.3 and 0.6, but increase both below and above these hematocrit levels. It is concluded that due to reduced vasodilatory reserve in working skeletal muscle compared to resting muscle the optimal hematocrit is shifted to higher values.

Animals↗