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Biomedical subjects

L Weber

Publications and source records attributed to L Weber.

At least 181 records · Page 10Linked to original sources
PubMed1983

Stimulation of chemiluminescence in bovine polymorphonuclear leucocytes by virus-antibody complexes and by antibody-coated infected cells.

The induction of CL in bovine polymorphonuclear granulocytes (PMN) by bovine herpes virus Type I was studied. Virus and virus-infected bovine embryonic lung cells were unable to stimulate cellular light emission. When virus and infected cells were incubated in the presence of immune serum, a burst of CL was induced in PMN. The mechanism of CL induction was dependent on the antibody Fc portion, as F(ab')2 fragments bound to antigen were unable to stimulate CL. These observations suggest that PMN may exert antiviral activity in the presence of a specific antibody. In addition, the measurement of antibody-induced CL represents a highly sensitive tool for the study of antigens present on the surface of viruses, and of viral antigens expressed on cell surfaces.

Animals↗
PubMed1983

Cardiac output by thermodilution technique. Effect of injectate's volume and temperature on accuracy and reproducibility in the critically Ill patient.

We compared determinations of cardiac output using various combinations of injectate volumes and temperatures to results obtained with 10 ml of iced (0 degrees C) injectate (standard technique) in 33 critically ill patients. The use of a 10-ml injectate at room temperature resulted in comparable reproducibility (12.7 vs 10.8 percent; not significant) and a small and nonsignificant error (-0.013 +/- 0.543 L/min). Five milliliters at room temperature resulted in markedly decreased reproducibility (17.9 vs 8.9 percent; p less than 0.05); however, the error associated with the technique was still not significant (0.136 +/- 0.829 L/min). When a 5-ml injectate at 0 degrees C was used, a reproducibility comparable to that of 10 ml at 0 degrees C was obtained (12.3 vs 7.5 percent; not significant). The results underestimated values obtained with 10 ml at 0 degrees C (-0.360 +/- 0.857 L/minute); however, the difference did not reach statistical significance. The use of 3 ml at 0 degrees C was associated with a substantial increase in variability, with a coefficient of variation of 32.0 percent (10.4 percent for 10 ml of iced injectate; p less than 0.01); however, the differences between the average value of cardiac output obtained with this technique and the standard technique were only minimal (error, -0.063 +/- 0.455; not significant). We reached the following conclusions: (1) the use of 10 ml at room temperature and 5 ml at 0 degrees C as the indicator for thermodilution determinations of cardiac output results in small and insignificant differences in reproducibility and accuracy from the standard technique; (2) five milliliters at room temperature and 3 ml at 0 degrees C are associated with markedly decreased reproducibility; however, the error in values for cardiac output obtained with these techniques is not statistically significant; and (3) the ability to use injectate at room temperature and in small volume should substantially simplify the technique, lowering its cost, and should prevent volume overloading.

Adult↗
PubMed1982

[Nocturnal changes in blood gases and pulmonary arterial pressure in chronic bronchitis patients with respiratory insufficiency (author's transl)].

Fourteen male patients with chronic bronchitis and respiratory insufficiency were monitored during nocturnal sleep by conventional polygraphy (EEG, EOG and EMG of the chin) associated with continuous recording of the mean pulmonary arterial pressure (PAP) and, in 50% of the cases, continuous measurement of O2 saturation. Six subjects were able to sleep long enough for oxygen saturation, blood gases and PAP values to be correlated with the various phases of sleep. Frequent, significant and sometimes abrupt peaks of hypoxaemia were observed; they usually, though not necessarily, occurred during paradoxical sleep. The most pronounced nocturnal changes in SaO2 were encountered in those patients who had the most severe hypoxaemia during daytime. Nocturnal fluctuations in PAP were also pronounced (with increases of more than 20 mmHg) and often paralleled changes in SaO2. Correlation between SaO2 and PAP was good in some patients ("responders") but poor or even lacking in others ("poor-or non-responders"). This preliminary study indicates that patients with chronic bronchitis may have severe exacerbations of pulmonary arterial hypertension during nocturnal sleep and warrant nocturnal oxygen therapy.

Adult↗
PubMed1982

Immunofluorescent localization of type IV collagen and laminin in human skin and its application in junctional zone pathology.

Purified antibodies against type IV collagen and laminin were used ot localize basement membranes by indirect immunofluorescence in various anatomical regions of normal and diseased human skin. The two proteins showed extensive codistribution. A continuous linear staining was found along the epidermal-dermal junction and around hair follicles, sebaceous gland acini and small capillaries. The same proteins also surrounded individual cells such as those found in vessels, hair erector muscles and subcutaneous tissue. Blister formation in bullous pemphigoi left type IV collagen and laminin on the floor of the blister, while the bullous pemphigoid antigen as detected by human autoantibodies was found on both sides of the blister. In solid basal cell carcinoma a strong staining was found around all tumour islands as well as focally within the cell clusters. This suggests that the tumour cells produce these basement membrane proteins but have lost, at least in part, control of polar deposition.

Adolescent↗
PubMed1982

[Bullous angiolymphoid hyperplasia with eosinophilia].

Two patients are described having a bullous variant of angiolymphoid hyperplasia with eosinophilia on the head. This disease is characterized by inflammatory, infiltrated, plaque-like lesions with recurring bullous eruptions. At the same time there may be prurigo-like papules on the trunk and arms. The course is a characteristic histological pattern revealing cutaneous lymphocytic infiltrate, lymphoid follicle formation, and atypical vascular proliferation associated with tissue eosinophilia. Blister formation takes place subepidermally.

Eosinophilia↗
PubMed1981

Characterization of a new aberration of the human Y chromosome by banding methods and DNA restriction endonuclease analysis.

Comparative cytogenetic analyses were performed with ten different banding methods on a previously undescribed, inherited structural aberration of a Y chromosome, and the results compared with those of normal Y chromosomes occurring in the same family. The value of the individual staining techniques in investigations of Y chromosomal aberrations is emphasized. The aberrant Y chromosome analyzed can be formally derived from an isodicentric Y chromosome for the short arm with a very terminal long-arm breakpoint, in which the centromere, an entire short arm, and the proximal region on one long arm was lost. This interpretation was confirmed by determining the amount of the two Y-specific DNA sequences (2.1 and 3.4 kb in length) by means of Hae III restriction endonuclease analysis. The karyotype-phenotype correlations in the men with this aberrant Y chromosome, especially the fertility dysfunctions (oligoasthenoteratozoospermia, cryptozoospermia), are discussed. The possibility of the existence of fertility factors involved in the control of spermatogenesis within the quinacrine-bright heterochromatic region of the Y long arm is presented.

Adult↗
PubMed1981

Scleroderma fibroblasts: some aspects of in vitro assessment of collagen synthesis.

Fibroblasts were cultured from skin biopsies of patients with systemic sclerosis in different stages of the disease. In vitro synthesis of collagen was checked after a pulse with tritiated proline. The ratio between type I and type III collagen was normal in all patients. Six of seven cultures derived from patients in the active state showed an increased synthesis of collagen relative to other proteins. Addition of serum (normal and diseased) to the culture medium did not stimulate synthesis of collagen in any culture with normal collagen synthesis.

Adult↗
PubMed1981

Actin acetylation in Drosophila tissue culture cells.

In a permanent cell line derived from Drosophila embryos, cytoplasmic actin is produced as an unstable precursor, which is subsequently converted to a stable form. This conversion results in a reduction in isoelectric point, with no apparent change in molecular weight. The conversion involves an enzymatic acetylation, and results in an insensitivity to aminopeptidase digestion, suggesting N-terminal blockage. Both the acetylated and unacetylated actins can participate in the assembly of F-actin, but with different efficiencies.

Acetylation↗
PubMed1981

Developmental neuropathology of mouse neocortex following early fetal X-irradiation.

X-irradiation of mice at a dose of 2.0 Gy on days 12 or 13 p.c. results in a clustering of neocortical ventricular-layer cells to rosettes and in the development of focal alterations consisting of glial cells in a typical radial arrangement. Both structures collapse at birth, either due to the invasion by thalamocortical axons, which results in disintegration of the rosettes, or to successive conversion of the glial spongioblasts to rather large astrocytes. The histogenesis of these perinatal events is described with special emphasis on the topographical differences in the developing brain.

Animals↗
PubMed1981

[Right ventricular function in patients with transposition of the great arteries after atrial inversion (Mustard procedure) (author's transl)].

Twenty-nine patients with transposition of the great arteries (TGA) and intact ventricular septum underwent hemodynamic and angiocardiographic investigation 18,8 +/- 5,8 months after inflow correction (Mustard). The mean age at operation was 14,6 +/- 7,5 months and in all, a good anatomical result was achieved. The hemodynamic parameters such as cardiac index, pressures in all heart chambers as well as in the venous channels and arterial vessels were found within normal limits. The end-diastolic volume of the right ventricle (RVEDV) was closely correlated to body surface area (r = 0,697). It increased, however, more rapidly than in children with normal hearts. Mean RVEDV/m2 was 86 +/- 8 ml which is 123 +/- 10% of the normal values for children (70 +/- 13 ml) according to Graham et al. The mean ejection fraction (EF) of the right ventricle (58 +/- 7%) was only slightly below the normal range (65 +/- 7%). Thus, a good hemodynamic function of the RV can be assumed at least for the early postoperative years after a Mustard operation. It remains open, however, if the more rapid increase of RVEDV/m2 expresses the RV adjustment to the afterload of the systemic circulation or if this should be interpreted as an early sign of RV functional impairment.

Angiocardiography↗
PubMed1981

[Diagnostic accuracy of pulmonary vessel blood flow assessed by roentgenography--a comparison with haemodynamic data (author's transl)].

The article reports on an examination of the diagnostic accuracy in assessing the pulmonary vessel blood flow via x-ray films of the thorax in 323 children by means of a comparison with the haemodynamic data of four examiners, on the basis of a Yes/No (True/False) decision. Overall accuracy in the total group of examined children--depending on the experience of the examiners--was 60 to 66%; in children below 2 years of age, it was 63-69%, and in children over 2 years old it was 59-65%. In a Left-Right Shunt smaller than 35%, accuracy was between 33 and 63%; if the Left-Right Shunt was greater than 57%, it was 81-97%. Diagnosis of reduced pulmonary blood flow proved more difficult than of an enhanced flow. Sensitivity of the examination method was 53-71%, whereas its specificity was 57-70%.

Child↗
PubMed1980

Sexual dimorphism of newborn mouse epithalamus after fractionated X-irradiation at late stage of organogenesis.

Fractionated X-irradiation with 3 x 0.95, 3 x 1.05, 3 x 1.15, or 3 x 1.35 Gy on gestational days 11-13 in the mouse results in two discrete, clearly distinguishable forms of an epithalamic malformation observable on gestational day 18. Type A is characterized by a rhombic shape of the dorsal diencephalic sulcus which first narrows at the occipital edge. The habenular diameters in the plane of the habenular commissure are in the range between 81 and 88% of the control measurements. The anterior colliculi are quite well developed. The type B lesion is characterized by a rather narrow epithalamus with a sandglass-shaped dorsal diencephalic sulcus and habenular diameters that are only about 56 to 64% of the control values. With the exception of the group with the lowest radiation dose (3 x 0.95 Gy), the type B lesion predominates. The B:A ratios are 1.5 and 1.6 in the highest dosage groups, and show the most drastic increase to a ratio of 4.0 after application of 3 x 1.05 Gy. Type B lesions occur in female fetuses at a higher frequency than in males and thus shows a clear-cut correlation with the frequency and severity of neocortical lesions in the same individuals. This is again most marked in the 3 x 1.05 Gy dosage group, where the type B lesion occurs five times more frequently in females than in males. This sexual dimorphism in the reaction pattern of the epithalamus after X-irradiation in utero, can best be explained by postulating a causal link with the forebrain lesions which were recently shown to exhibit similar sexual dimorphism. We therefore postulate a retrograde transsynaptic degeneration of the thalamo-cortical fibres that develop pre-term, which is significantly expressed only after a low X-irradiation dose, but is partly abolished in the higher dosage groups. This leads to hypoplastic alterations of the epithalami, a secondary phenomenon to the neocortical lesions in the animals most affected. The resulting dysfunction of the epithalamus in the immediate neonatal period is then responsible for the preferential death of the animals with B-type lesions and also explains why female mortality is significantly higher than male mortality which occurs only in the 3 x 1.05 Gy dosage group.

Abnormalities, Radiation-Induced↗