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Biomedical subjects

A Alanen

Publications and source records attributed to A Alanen.

At least 91 records · Page 5Linked to original sources
PubMed1988

B cell precursors in chick embryos surgically bursectomized at 72 h of incubation.

To determine the presence of precursor B cells in chick embryos surgically bursectomized at 72 h of incubation (E-Bx) we studied chick chimeras that were produced by establishing parabiotic connections between blood vessels of chorioallantoic membranes of normal and surgically bursectomized chick embryos. Using sex chromosomes and a B cell alloantigen (Bu-1a) as markers we showed that chick embryos bursectomized at 72 h of incubation contain B cell precursors capable of colonizing the bursa of Fabricius and developing into B lymphocytes. The repopulation capacity of 14-day-old embryonic spleen cells from E-Bx recipients was tested by transferring them into age-matched X-irradiated Bu-1-disparate embryos. The results show that B cell precursors are present in 14-day spleen of chick embryos bursectomized at 72 h of incubation. These precursors carry the Bu-1 B cell alloantigen, suggesting that commitment to the B cell lineage can take place in the absence of bursa.

Age Factors↗
PubMed1988

Paramagnetic contrast enhancement at 0.02 T: an experimental study using Gd-DOTA in normal and hydronephrotic kidneys.

Both normal and experimentally hydronephrotic rabbits were imaged at 0.02 T using partial saturation (PS 160/30) and inversion recovery (IR 1000/200/40) sequences. The signal intensity of normal renal medulla and cortex markedly increased after the injection of 0.1 mmol/kg of Gd-DOTA. In the unilateral total hydronephrosis the dilated renal pelvis did not contrast enhance after 15 and 35 min of Gd-DOTA injection. The enhancement pattern was similar in 1- and 3-week-old hydronephrosis. The effect of Gd-DOTA on renal T1 times at 0.02 T was studied using rats. Fifteen minutes after the Gd-DOTA injection (0.1 mmol/kg) the T1 times of excised rat kidneys decreased from 311 to 90 ms. The authors conclude that the enhancement of the MR signal of the kidney by Gd-DOTA at an ultralow magnetic field (0.02 T) is similar to its enhancement at higher fields (greater than 0.15 T).

Animals↗
PubMed1988

A new ultrasonic technique for quantifying blood echogenicity.

The echogenicity of blood varies with the conditions of flow. This study introduces a new technique for quantifying blood echogenicity and includes digitalization of the signal from an A-mode ultrasound scanner, integration, subtraction, and computer analysis of the signal. Shear rate (directly proportional to velocity) had an inverse relationship to the blood echogenicity. Hemodilution with Ringer's solution and with low-molecular-weight dextran 1 decreased blood echogenicity, whereas the addition of a macromolecular protein (dextran 70) increased blood echogenicity. This technique makes possible a quantitative analysis of the factors affecting blood echogenicity.

Blood Circulation↗
PubMed1988

Examination of infant brain maturation using ultra low field MRI.

The brains of 42 newborn infants were examined with MRI at 0.02 T field, and regional variations of T1 relaxation time were measured from the images. There were three groups: 1. full term infants (9), 2. preterm infants (10) and 3. SGA (= small for gestational age) infants (20). Relaxation times showed a correlation to myelination of the brain. The brain of SGA infants showed a large variation in their T1 values.

Brain↗
PubMed1988

Evaluation of 144 cases of ileal conduits in adults.

Ileal conduit urinary diversion was performed on 144 patients (138 malignant tumours, 6 benign conditions) according to the method of Bricker. Operative mortality was 4.2%. Early complications occurred in 33% and late complications in 28% of the patients. In 19% a reoperation was necessary for complications. Pre- and postoperative urographies were compared in 83 cases: there was deterioration of the upper urinary tracts in 26% of the right and 39% of the left renal units.

Adult↗
PubMed1987

Mott cells: a model to study immunoglobulin secretion.

Mott cells are plasma cells defective in immunoglobulin (Ig) secretion. They display this defect by accumulating Ig in the rough endoplasmic reticulum, detectable by Ig+ intracellular inclusion. We have previously produced hybridoma cell lines (Alanen, A. et al., Eur. J. Immunol. 1985. 15: 235) in which this phenotype is preserved, and shown the inability of these cells to secrete the Ig. In order to study this defect further, we fused these hybridoma cells with a kappa-secreting hybridoma cell line, Sp1, and, using double selection with hypoxanthine, aminopterin, thymidine and ouabain, obtained hybrid cell lines expressing various combinations of the three Ig chains involved (Mott gamma 1, Mott kappa and Sp1 kappa chains). We studied the presence of Ig+ inclusions in these cells as well as Ig secretion by metabolic labeling and immunoprecipitation. All inclusion-positive clones expressed both Mott heavy and Mott light chains with or without the Sp1 light chain, whereas none of the inclusion-negative clones produced both Mott-derived Ig chains. In all of the clones, even those with inclusions, the Ig secretion was at least partially rescued by the fusion. This occurred also in an inclusion-positive clone which maintained the original Ig status of the Mott without Sp1 kappa chain, indicating a complementation by the cell fusion of some cellular factor involved in Ig secretion. Furthermore, we injected Xenopus oocytes with mRNA isolated from three different original Mott cell hybridomas and could show secretion of the Ig, which is not secreted from the original Mott cells, from the oocytes.

Animals↗
PubMed1987

Multilocular renal lesions--a diagnostic challenge.

We present six patients with benign cystic lesions of the kidneys and one with a cystic carcinoma with preoperative diagnostic difficulties. Despite the advent of modern imaging techniques and aspiration cytology there are no unequivocally reliable diagnostic signs of benignity in multilocular renal lesions. Therefore surgery is recommended as the therapy of choice.

Adult↗
PubMed1987

Healing of a muscle trauma. Correlation of sonographical and histological findings in an experimental study in rats.

Healing of a partially ruptured gastrocnemius muscle was studied in rats with sonographical and histological techniques. Ultrasonography was performed 1-21 days after injury using a 7.5-MHz linear scanner. Following ultrasonography, the injured muscles were examined histologically. The injured area and development of hematoma were visualized during the first 5 days after trauma with ultrasonographical and histological observations. Later, disorganization of regenerating muscle fibers appeared sonographically more clearly than the scar tissue area demonstrated histologically. The present study points out the accuracy of ultrasonography in the examination of a muscle trauma, especially during the early phases of healing.

Animals↗
PubMed1985

Mott cells are plasma cells defective in immunoglobulin secretion.

Plasma cells containing intracellular inclusions of immunoglobulin (Russell bodies) are known as Mott cells, and are found in large numbers in lymphoid organs in autoimmune mice. Hybridoma technique was used to produce cell lines of this phenotype by fusing spleen cells from a NZB mouse with a nonproducing hybridoma cell line (Sp2/0-Ag14), allowing us to carry out studies of this cell type at the biochemical level. Ultrastructurally the inclusions were distended cisternae of rough endoplasmic reticulum, suggesting a block in the secretory pathway of the cells. Biosynthetic labeling studies confirmed that these cell lines have either a complete or partial block of secretion of immunoglobulin, possibly due to an abnormal light chain.

Animals↗
PubMed1985

Ultrasonic echoes registered from erythrocytes.

Erythrocytes at various concentrations were examined with a sensitive A-mode ultrasonic scanner; simultaneous measurements were made under light microscopic control. Individual erythrocytes caused weak (about 1 dB) echoes while erythrocyte aggregates (ten to 100 cells) produced stronger echoes (up to 15 dB), grossly proportional to the size of the aggregates. The latter type echoes were characteristic of higher erythrocyte concentrations (hematocrit 0.1 - 0.8). It is concluded that these echoes originate from red cell aggregates within the stagnant blood.

Erythrocyte Aggregation↗
PubMed1985

Correlation of the echogenicity and structure of clotted blood.

The echogenicity of clotting human blood in sterile plastic bags was studied for up to 21 days and correlated with the histology of the clots. As observed with a 6-MHz A-scanner and a 5-MHz real-time gray-scale scanner, fresh blood and fresh clots were rich in internal echoes. The blood clot gradually became anechoic as a result of erythrocyte packing, hemolysis, and formation of fibrin thrombus, except for the irregular upper border, which also remained histologically inhomogeneous. This study shows that the echogenicity of a hematoma or clot is dependent on its histology; namely, on the distribution and integrity of cells within the clot.

Blood Coagulation↗
PubMed1984

Circulating immune complexes in hypertensive disorders of pregnancy.

Circulating immune complexes (CICs) were measured in sera of pregnant women with pre-eclampsia and other hypertensive disorders of pregnancy and pregnant women with renal disease, using four different CIC assays: platelet 125I-labelled staphylococcal protein A test ( PIPA ), conglutinin-binding ELISA, C1q-binding ELISA and rheumatoid factor binding inhibition ELISA. CICs were shown to be present in the sera of 47% of women with severe pre-eclampsia, in 20% with mild pre-eclampsia and in 18% of women with normal pregnancy using the PIPA test. The PIPA test was capable of discriminating between patients with renal disease, which were all positive, and women with uncomplicated hypertension, which were all negative. All patients positive in the PIPA test, and most patients with a positive RFbI -ELISA test, had various amounts of proteinuria. Although half of the women with severe pre-eclampsia showed the presence of CICs in the PIPA test, the amount of these complexes was low and not constant in serial samples from the same patient.

Antigen-Antibody Complex↗
PubMed1984

Serum IgE and smooth muscle antibodies in pre-eclampsia.

The serum IgE concentrations and the occurrence of autoantibodies were measured in 20 women with preeclampsia and in 17 women with normal pregnancy. All women studied were primigravid and matched according to the age and the duration of pregnancy. The serum IgE concentration was higher in pre-eclampsia. Antinuclear and antimitochondrial antibodies were found only occasionally, whereas smooth muscle antibodies were found in preeclamptic women more often than in normal pregnancy. These results are in agreement with the findings of disturbed immune function in pre-eclampsia, but do not clarify the etiology of this disorder.

Antibodies↗
PubMed1984

Real time sonographic diagnosis of adrenal haemorrhage.

The diagnosis of adrenal haemorrhage in 4 infants using a linear real-time ultrasound scanner is described. The resolution of real-time equipment appears to be sufficient for such a diagnosis and its flexibility is well suited for small babies.

Adrenal Gland Diseases↗
PubMed1984

Predicting malignancy of suspected ovarian tumours by CT.

The CT appearance of 47 clinically suspected ovarian tumours was analysed and compared to operative findings. By using simple differential diagnostic criteria, such as the relative amount of cystic and solid tumour tissue, presence of ascites and density readings, it was possible to correctly predict the malignancy of 18 out of 20 primary and 4 out of 5 recurrent ovarian tumours. In 6 out of 16 benign ovarian tumours or pelvic masses the CT pattern was either indeterminate or similar to malignant neoplasms. Since some non-ovarian tumours may produce an identical picture, the site of origin of large tumours could not be always detected. CT provides significant complementary information on the characteristics of suspected ovarian malignancies. A tumour which has a typical benign, cystic CT appearance is very likely benign, while some of the masses which contain solid tissue, consistent with a malignancy, may still be benign.

Adenocarcinoma↗
PubMed1982

Cell-mediated immunity in normal pregnancy and pre-eclampsia.

The in vitro responses of maternal lymphocytes to phytohaemagglutinin (PHA), concanavalin A (Con A) and purified protein derivative of tuberculin (PPD) were determined in uncomplicated and pre-eclamptic pregnancies and nongravid female controls. PHA, Con A and PPD responses were significantly lower in both pregnant groups compared to nongravid controls. No difference was observed in lymphocyte reactivity between women with pre-eclampsia or uncomplicated pregnancy. Both pregnant groups exhibited normal numbers of circulating T and B lymphocytes. The number of active E rosette-forming cells was significantly higher in peripheral blood of pre-eclamptic patients.

Adolescent↗