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Biomedical subjects

J Krüger

Publications and source records attributed to J Krüger.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of centromere arrangements and test for random distribution in G0, G1, S, G2, G1, and early S' phase in human lymphocytes.

The arrangement of centromeres, cluster formation and association with the nucleolus and the nuclear membrane were characterized in human lymphocytes during the course of interphase in a cell-phase-dependent manner. We evaluated 3,893 cell nuclei categorized by five parameters. The centromeres were visualized by means of indirect immunofluorescent labeling with anti-centromere antibodies (ACA) contained in serum of patients with CREST syndrome. The cell nuclei were classified as G0, G1, S, G2, G1' and early S' phase by comparing microscopically identified groups of cell nuclei with flow cytometric determination of cell cycle stage of synchronized and unsynchronized lymphocyte cell cultures. Based on a discrimination analysis, a program was devised that calculated the probability for any cell nucleus belonging to the G0, G1, S, G2, G1' and early S' phase using only two microscopic parameters. Various characteristics were determined in the G0, S, and G2 stages. A transition stage to S phase within G1 was detected. This stage shows centromere arrangements not repeated in later cell cycles and which develop from the dissolution of centromere clusters in the periphery of the nucleus during G0 and G1. S phase exhibits various non-random centromere arrangements and associations of centromeres with the nucleolus. G1' and early S' phase of the second cell cycle display no characteristic centromere arrangement. The duplication of centromeres in G2 is asynchronous in two phases. For all cell phases a test for random distribution of the centromeres in the cell nucleus was performed. There is a distinct tendency for centromeres to be in a peripheral position during G0 and G1; this tendency becomes weaker in S phase. Although the visual impression is a seemingly random distribution of centromeres in G2 and G1', statistical analysis still demonstrates a significant deviation from random distribution in favor of a peripheral location. Only the early S phase of the second cell cycle shows no significant deviation from a random distribution.

Cell Cycle↗
PubMed1992

[Lymphocytograms in relation to storage time of CPDA1 whole blood concentrates].

Immunocompetent cells have been shown to be effective in immunosuppression after blood transfusion. The analysis of leukocytes by electronic cell counter and of lymphocyte subsets by flow cytometry in stored whole blood revealed a decay of granulocytes within the first day of storage. T-lymphocyte subpopulations and natural killer cells continuously decrease over the time of storage, whereas B lymphocytes are very stable during the first 2 weeks. After 4 weeks lymphocyte subsets had decreased by the following values: total lymphocytes 46.0%, CD3+ 78.3%, CD4+ 80.1%, CD8+ 81.3%, CD19+ 65.9%, CD16/56+ 74.8% and CD3/DR+ 89.5%. Therefore leukocyte removal should be achieved as soon as possible after collection.

Antigens, CD↗
PubMed1992

[Leukocyte depletion, a comparison of the "Leukotrap in-line" filter system with a sterile added 4-bag Speacell-R-500-A filter system].

Leukocytes in RBC preparations have a variety of immunologic effects in transfused patients. Not only their elimination at time of transfusion but before storage seems to be advantageous. Filtration with the Leukotrap system at the day of preparation led to an overall reduction of leukocytes of 82.2%, i.e. an average of 5.4 x 10(8) leukocytes/RBC concentrate. Filtration with a Sepacell R 500 A eliminated 99.0% of leukocytes, 3.4 x 10(7) cells remained per blood unit. The determination of lymphocyte subpopulations by flow cytometry after filtration with the Leukotrap system showed a more effective adsorption of B cells than of T and natural killer cells.

Adsorption↗
PubMed1992

[Distribution of the incidence of SGPT activity in blood donors].

Predonation SGPT (ALT) testing was performed in 5,706 blood donors (3,944 male, 1,762 female) with the Reflotron system. The values of SGPT activities (IU/l; 25 degrees C) are not normally distributed, whereas the log10 SGPT distribution is largely Gaussian (the arithmetic mean log10 +/- SD for female donors is 0.98 +/- 0.14 and for male donors 1.08 +/- 0.16, the antilog of the mean log10 9.5 and 12.1 IU/l, respectively). In the following the impact of SGPT testing at various exclusion levels on the percentage of deferred donors is shown: (1) female: cutoff level > 18.0 IU/l (mean log10 +2.0 SD) 2.8%, > 19.5 IU/l (+2.25 SD) 2.1%, > 21.1 IU/l (+2.5 SD) 1.8% and > 24.8 IU/l (+3.0 SD) 1.2% deferment. (2) male: cutoff level > 25.2 IU/l (mean log10 +2.0 SD) 2.7%, > 27.6 IU/l (+2.25 SD) 2.3%, > 30.3 IU/l (+2.5 SD) 1.4% and > 36.4 IU/l (+3.0 SD) 0.8% deferment. Using the current cutoff value of > 45 IU/l (according to German regulations, 1987) only 0.2% female (with SGPT > mean log10 +4.5 SD) and 0.3% male (with SGPT > mean log10 +3.5 SD) donors would be excluded. These findings demonstrate that different SGPT exclusion levels for men and women are necessary and that the current cutoff value of > 45 IU/l does not exclude donors who should better be rejected.

Alanine Transaminase↗
PubMed1992

[Etiology of increased SGPT activity in blood donors].

From all blood donors screened within a given period of 6 months for SGPT (ALT) immediately before donation, 166 (141 male, 25 female) were found to have SGPT activities above our cutoff value of > 28 IU/l (25 degrees C). In order to define the characteristics of these blood donors they were asked for detailed medical history followed by a thorough physical examination and further serologic and biochemical testing. Factors associated with elevated SGPT activity included daily alcohol consumption (82 donors), infections associated with abnormal DCs (23), therapy with hepatotoxic drugs (8), infections that had been treated with antibiotics (6), strenuous physical exercises (5), body building supported by anabolics (2), acute HBV infection (1), acute HCV infection (1), alcohol/drug abuse and positive test for anti-HCV antibodies (1), anti-CMV positivity with absolute and relative lymphocytosis (1). In 36 cases factors that could have been associated with an increased SGPT activity were not verified. A critical valuation of the presently accepted cutoff value of 45 IU/l (25 degrees C) is given.

Alanine Transaminase↗
PubMed1992

[Diagnosis of the presence of SGPT in blood donors].

Presampling determination for hemoglobin has been pursued for a long time, but now it is becoming possible to examine further parameters such as SGPT (ALT). The SGPT predonation testing is best performed with the Reflotron system (Fa. Boehringer Mannheim) since whole blood samples drawn into capillary tube can be used. Between 1985 and 1988 1.35-1.75% of an average of 22,000 whole blood donations were found to have SGPT levels above the accepted cutoff (> 30 IU/l, 25 degrees C). The cost per test using the UV kinetics and the overall expenses of unusable collections were compared with the cost of SGPT predonation testing. An average of DM 20,000.-per year has been saved. Therefore prescreening of SGPT in blood banking is a highly cost-effective approach.

Alanine Transaminase↗
PubMed1992

[Evaluation of economic business management in the hospital. Results from four neurosurgical clinics].

An audit of economicalness performed by one company from 1980 to 1985 in four neurosurgical departments is presented. The report is restricted to medical care. There is a considerable difference in findings: in the department first looked at there are 3.8 patients per surgeon and in the 1985 examination 5.4. These departments being well comparable otherwise both judgement and competence of the business consultants involved must be questioned.

Cost-Benefit Analysis↗
PubMed1992

[Iatrogenic diagnostic delay in rectal cancer].

From a case material of 151 rectal carcinoma patients it has been established that the duration of anamnesis from the first consultation of the doctor to the onset of treatment was in 40 percent of the cases longer than 3 months, and in 17 percent of the cases, longer than 6 months. Only 36 percent of the patients with clinically manifest disease underwent diagnosis within a month following the first consultation of the doctor; in 37 and 15 percent of the cases, diagnosis was made only after 3 and 6 months, respectively. The causes of iatrogenic delay of diagnosis are analyzed and demonstrated by typical examples.

Diagnosis, Differential↗
PubMed1992

[Hemostasis in neurosurgical operations. A comparative study between collagen fleece (Lyostypt) and a gelatine sponge (Marbagelan)].

A study of 100 patients each with neurosurgical operations is reported, in which a prospective randomized and controlled investigation compares two haemostyptic agents, Marbagelan and Lyostypt. Collagen fleece was found superior to gelfoam as to haemostasis although slightly less convenient in application. Postoperative complications specific to the haemostyptic agents were not seen.

Adolescent↗
PubMed1991

[Aortobronchial fistulae as late complications following the surgical correction of aortic isthmus stenosis].

Three patients (2 men, aged 39 and 52 years, one woman, aged 47 years) developed hemoptysis 3-19 years after surgical resection of coarctation of the aorta. Digital subtraction angiography in the two men was suspicious of an aortobronchial fistula. An emergency thoracotomy revealed the diagnosis in the woman: she died during the operation of intractable arterial bleeding, the initial operation having been atypical (insertion of a graft extending across the isthmus to the ascending aorta). The 52-year-old man died of left heart failure after pneumonectomy (for massive bleeding into the left lung). An aneurysm sack at the aortic isthmus was resected and a vascular graft implanted in the 39-year-old man. There have been no further hemoptyses. These cases emphasize the need for including aortobronchial fistula as a cause of hemoptysis.

Adult↗
PubMed1991

Triosephosphate isomerase deficiency: haemolytic anaemia, myopathy with altered mitochondria and mental retardation due to a new variant with accelerated enzyme catabolism and diminished specific activity.

A new triosephosphate isomerase (TPI) variant is described in an 8-year-old Turkish girl suffering from chronic haemolytic anaemia, myopathy and developmental retardation since early infancy. The enzyme activity profile revealed a generalized deficiency in erythrocytes, granulocytes, mononuclear blood cells, skeletal muscle tissue and cerebrospinal fluid. The concentration of enzyme substrate dihydroxyacetone phosphate was distinctly elevated. Biochemical examination showed accelerated enzyme deamidation, the first step in the normal catabolism of TPI during aging of the erythrocyte. The specific activity of the variant TPI, determined by antibody titration, was reduced to 61% of normal. Its heat stability was markedly decreased. Muscle biopsy and neuropsychological testing further clarified the pathogenesis of the disorder. A prevalent alteration of mitochondria similar to that seen in mitochondrial myopathy and an elevated amount of intracellular glycogen were found. The patient's retarded intellectual development was mainly due to impaired visual perception and sensory-motor co-ordination in addition to a lack of syllogistic reasoning. The findings indicate that the low TPI activity leads to a metabolic block of the glycolytic pathway and hence to a generalized impairment of cellular energy supply.

Anemia, Hemolytic↗
PubMed1991

Recognizing the visual stimulus from neuronal discharges.

In this article, experiments are reviewed that have a bearing on the question of how 'meaning' is related to neuronal activity in the mammalian cortex; there is evidence that the excitation time pattern plays a major role. We suggest that 'objective meaning' is related to spatiotemporal activity distributions, whereas spike counts indicate the importance of the contribution of a given neurone to that meaning. Such a 'dual-coding' principle allows the visual system to emphasize selected activity components by central messages. The feature to be noted is that the objective meaning remains largely unaltered.

Action Potentials↗
PubMed1991

A modular approach to multichannel magnetometry.

A 19-channel SQUID system for biomagnetic measurements has been developed. This system differs from standard instruments in its modular approach. Various gradiometers can be coupled to the SQUIDs, the cryogenic system allows the exchange of single channels and the electronics is based on a cassette system. Problems with thermal insulation, vibrations of the gradiometers and tilted gradiometer geometries are discussed and solutions are presented.

Equipment Design↗
PubMed1991

[Status of local excision of local deep rectal cancers with curative intention].

103 cases have been analyzed retrospectively to define the indication for local extirpation of small and deep-seated rectum carcinomas with curative purpose. While pedunculated carcinomatous adenomas can be removed by endoscopic loop extraction, the non-sessile polypous carcinomas have to be radically extirpated by excision from intestinal wall resection is a promising procedure. Here, the transanal access by means of a funnel-shaped, lateral fenestrated glass speculum as introduced by Dewey yields better results than the rectotomia posterior.

Adult↗
PubMed1991

Influence of the trapidil derivative AR 12463 on serum and tissue lipids and development of aortic lesions during experimental atherosclerosis in rabbits.

Daily administration of the trapidil derivative AR 12463 (20 mg/kg body weight i.p.) to cholesterol-fed rabbits diminished statistically significantly the increase in serum total cholesterol. After 8 weeks of treatment all measured lipoprotein fractions were significantly lower in animals treated with AR 12463 (group 3) compared with the values of the untreated control (group 1) or vehicle-treated group (group 2). The reduction of serum levels was associated with statistically significantly reduced levels of cholesterol esters in kidney, liver and aorta. The levels of free cholesterol in the liver of group 3 animals were statistically significantly lower compared with the levels in the two other groups, whereas in kidney and aortas the levels of free cholesterol remained unchanged under the influence of AR 12463. The area of aorta covered with fatty streaks was significantly smaller in group 3 versus group 1. The results of this study indicate that treatment of rabbits with AR 12463 while feeding a cholesterol-rich diet prevents hypercholesterolemia as well as the cholesterol incorporation into tissues. The mode of action of AR 12463 on serum and tissue lipids as well as on the development of atherosclerosis is discussed.

Animals↗
PubMed1990

Two types of neuronal synchrony in monkey striate cortex.

Peaks in more than 5000 spike train correlograms, obtained from monkey striate cortex, were measured. Earlier work had shown qualitatively that there are frequent prominent peaks having widths in a range around 50 ms, and narrower peaks less than about 7 ms wide. Here we demonstrate that the distribution of peak widths shows a dichotomy.

Animals↗