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Biomedical subjects

M Donner

Publications and source records attributed to M Donner.

At least 73 records · Page 4Linked to original sources
PubMed1984

In vitro modulation of murine natural killer cytotoxicity by zinc.

The in vitro effects of zinc on natural killer (NK) activity of murine spleen cells were studied. The pretreatment of splenocytes with non-toxic concentrations of ZnSO4 induced a decrease of lytic activity against YAC-1 and RDM4 targets. The lytic function of non-activated and poly(I) X poly(C)-activated NK cells was similarly inhibited. When the interaction of effector cells with zinc was studied for 5 min, a significant inhibition of NK lysis was noted, which was maximal after 30 min. Zinc was undoubtedly responsible for the observed effects, since the concurrent addition of both zinc and suitable concentrations of o-phenanthroline, a Zn++ chelating agent, made it possible to maintain a normal level of lysis. Moreover, the pretreatment of spleen cells with increased concentrations of o-phenanthroline also inhibited NK lysis, suggesting that a physiological intracellular zinc content is required to maintain an optimal lytic function of NK cells. Although the lysis was completely suppressed after the addition of 10(-4) M ZnSO4, the frequency of target-binding cells (TBC), which was assumed to represent the first stage of NK-mediated cytolysis, was only partly inhibited. The results are discussed in view of a possible action of zinc on cell membrane functions, enzyme systems, and release of lymphokines.

Animals↗
PubMed1984

Delayed onset of hemothorax: an unusual complication of subclavian access for hemodialysis.

Subclavian catheterization for acute hemodialysis has become routine in many institutions. Immediate complications of this technique are dramatic and easily recognized, whereas late complications are less common, frequently insidious and tend to be more severe. We report the delayed occurrence of a right hemothorax following two hemodialysis treatments with a left subclavian access. Pertinent literature is reviewed.

Catheterization↗
PubMed1984

Interests and limits of continuous excitation photo-physical methods applied to cellular rheology.

It is possible to characterize the cohesion of the lipidic zones in cells or in membranes by using molecular emission spectroscopy techniques such as : fluorescence polarization, quenching reactions, intramolecular reactions. However, applying these techniques in biology can be improved by the use of pulsed excitations leading to the time-resolved evolutions of some properties of the probe, which can themselves be a function of their environment. The first and the last techniques, based on the use of diphenylhexatriene and dipyrenylpropane respectively are used in practice by steady state excitation. In the case of fluorescence polarization, it can be shown that the method can be applied, within certain limits, which have to be precised when studying the modifications in the membranes. This is also partly true for methods based on the use of intramolecular reactions. However these continuous excitation techniques usually only lead to a global result which is a function of several spectroscopic parameters and of the "cohesion" of the membrane. Then it can be shown that to go beyond this step of semi-quantitative analysis, it is necessary to use pulsed or modulated excitation methods. Moreover this more sophisticated technical approach implies a new theoretical effort to understand the molecular dynamics of the membranes.

Animals↗
PubMed1983

EEG in neonatal herpes simplex encephalitis.

The EEGs of 21 newborns with herpes simplex encephalitis were analysed. The diagnosis was based on the demonstration of herpes simplex infection in association with neurological symptoms, other etiological factors being excluded. Sixteen of 21 babies (76%) showed in their EEGs electrical seizures, either focal or unilateral. These paroxysms consisted of sharp waves or slow waves repeating at pseudo-periodic intervals, usually of 0.5-2 sec. Individual paroxysms had a duration of 10-20 sec in 6 babies and 1-2 min in 10 patients. During the same period, 20 other babies displayed the same EEG finding. Of these, 11 had encephalitis of unknown etiology. In our series there appeared to exist a correlation between both the duration of the electrical seizures and the degree of EEG background abnormality and the clinical outcome. Babies with markedly abnormal background and long-lasting paroxysms tended to have a poor prognosis. It is concluded that in newborns with clinical signs of encephalitis who show in their EEGs paroxysms of the type described, the possibility of herpes simplex encephalitis should be considered.

Electroencephalography↗
PubMed1983

Clinical appearance and outcome in mumps encephalitis in children.

Forty-one patients with mumps encephalitis examined at the Department of Paediatrics, University of Helsinki, during the period Jan. 1, 1968, to Dec. 31, 1980, were reviewed with special reference to clinical appearance and outcome. The ratio of males to females was 4:1 and the age range 1.2 to 13.7 years. The clinical findings were high fever greater than or equal to 39 degrees C in 83.0%), impairment of locomotion and balance (36.6%), seizures (24.4%), psychic disorders (22.0%), depressed level of consciousness (19.5%), vertigo (12.9%) and/or gastric pains (12.9%). One patient with congenital toxoplasma and cytomegalovirus infections died. On leaving the hospital eight were still ataxic, one of these was not able to speak and two had difficulties in concentration. One patient was transferred to another hospital because of psychosis. At the follow-up examination 4 to 24 months after the onset of the disease two patients were ataxic and seven suffered from behavioural disturbances. Electroencephalography (12.2% of all and 25% of examined patients) showed generalized slow wave disturbance at follow-up in six patients and borderline disturbances in eight.

Adolescent↗
PubMed1983

Resistance and susceptibility to pulmonary metastasis of Lewis lung carcinoma in different mouse strains.

The ability of the highly metastatic 3LL tumor of C57Bl/6 (H-2b) origin to form pulmonary metastases after an intramuscular transplantation was investigated in various allogeneic mouse strains. Metastatic proliferation was observed in all tested strains of B10 genetic background. In mice of A genetic background, metastases formation was reduced and a strong resistance to metastatic progression seemed to require the association of the A genetic background with the H-2f haplotype (A.CA strain). Determination of 3H-TdR uptake in the lungs of C57Bl/6 and A.CA mice bearing large local tumors confirmed these results. The development of lung tumor nodules following an intravenous injection of 3LL tumor cells was also different in these two strains. Thus, A.CA strain appears as a useful model system for studies of mechanisms involved in metastases formation.

Animals↗
PubMed1983

Mutagenicity of rubber additives and curing fumes. Results from five short-term bioassays.

The mutagenicity of rubber additives and curing fumes from some rubber formulations were studied in five short-term tests: point mutations in Chinese hamster V79 cells, the induction of sister chromatid exchanges in Chinese hamster ovary cells, micronuclei in erythrocytes of Chinese hamster bone marrow, sex-linked recessive lethal mutations in Drosophila melanogaster, and reverse mutations in the Salmonella/microsome assay. When 46 rubber additives were tested with Salmonella, 15 compounds were mutagenic, 16 were negative, and 15 were negative with no observed toxicity. Only one negative response was obtained for the nine tested samples of curing fumes. Thiuram and dithiocarbamate additives and some curing fumes with mutagenic responses in Salmonella were the primary objects of study in the other four test systems. Although the results of these four tests did not completely parallel the Salmonella results, they indicate that the individual compounds and the curing fumes from different types of rubber formulations may involve genotoxic risks.

Air Pollutants, Occupational↗
PubMed1983

[Determination of the membrane fluidity of human blood platelets by measuring the anisotrophy of the fluorescence emission].

Incorporation in vitro of 1,6-diphenyl-1,3,5 hexatriene (DPH) in washed human blood platelets was studied to determine a reference value of fluorescence emission anisotropy of DPH and thus the "microfluidity " of platelet lipid zones. Parameters evaluated were the effect of time of incorporation of the marker, of temperature (25 and 37 degrees C), and of cellular concentration, as well as the effect of platelet aging, enabling determination of valid experimental conditions for studying interaction with drug molecules.

Blood Platelets↗
PubMed1982

Interdisciplinary teaching of community paediatrics.

An experiment of combining decentralized and interdisciplinary teaching is described. Seminars were arranged at a district hospital for medical, nursing and social work students to discuss families with a chronically ill child. The purpose of these seminars was to teach co-operation between different health care workers, and to stress the importance of becoming acquainted with the family situation, and learn what a child's illness means to the whole family. An evaluation of the first three seminars shows that this type of teaching was very well received by the students, professionals and families concerned. The students considered house calls an important part of their education and felt that more interdisciplinary teaching should be included in their curriculum. In addition to the teaching aspect, the families involved also considered the seminars a positive experience as they receive more information about their child's disease, and deficiencies in treatment could be corrected.

Attitude to Health↗
PubMed1981

Kinetics of partly diffusion-controlled reactions. VIII. Excimer formation in the case of a model of cylindrical symmetry.

Spectrofluorimetric methods allowing an estimation of the "microviscosity" (or the microfluidity) of synthetic and natural membranes may be used if the emissive phenomenon is dependent upon the cohesion of its local environment. Of the different methods that may be proposed, the study of the reactions between electronically excited molecules A*, which emit fluorescence, and B quenchers embedded in membranes, the rate constant of which is partly controlled by diffusion, are expected to inform about the values of diffusion coefficients of quenchers and therefore the "microviscosity" of the environment. Information may be improved when the product of the reaction between A* and B is itself emissive (excimers, exciplexes). We propose here that a kinetic model may apply this type of reaction when a process of static quenching occurs. The use of this kinetic model in studies carried out in this area should lead to a more accurate determination of the diffusion coefficients of A* and B, and therefore of the "microviscosity".

Diffusion↗
PubMed1981

A comparative study of some growth characteristics and cell-surface properties of neoplastic cells.

Tumour cells from a polyoma-induced ascitic tumour were fractionated on the basis of the electrical charge on the cell surface by free-flow electrophoresis. Several characteristics of tumour cells have been investigated: (1) differences in the proliferation and antigenicity within the tumour at any point in time; (2) variation in proliferative potential with the ageing of the tumour. In early ascitic tumours, electrophoretically fractionated cells exhibit very similar proliferative characteristics. However, most DNA synthesis was found in slow-moving cells. The behaviour of older tumours was different. Proliferative potential and DNA synthesis were weaker and restricted to slow-moving cells, suggesting that fast-moving cells in older tumours were resting cells. An enrichment in immunoglobulin-bearing cells was also found in slow-moving cell fractions, supporting the hypothesis of variability in expression of tumour-specific antigens. The role of cell-surface properties and cell kinetics is discussed in relation to electrical surface charge, which might be involved in cell dissemination and metastasis. Thus, free-flow electrophoresis represents a satisfactory approach to isolate tumour cell subpopulations with characteristics such as high proliferative potential or increased expression of tumour antigens.

Animals↗
PubMed1981

Neurodevelopmental screening at five years of children who were at risk neonatally.

A neurodevelopmental screening test with cumulative scoring for abnormal test responses was performed on 845 five-year-old Finnish children who, in the newborn period, had had disorders which placed them in a high-risk group, and on 70 controls. The results showed a significant difference between the neurodevelopmental scores of the risk-group children and those of the controls. The scores were higher if the child had had many of the risk factors simultaneously. Boys had significantly higher scores than girls. The mean scores also varied between different risk factors. It is evident that slight neurodevelopmental deviations at the age of five years can derive from disorders in the newborn period.

Child, Preschool↗
PubMed1980

ACTH therapy in infantile spasms: side effects.

162 children with infantile spasms were treated with ACTH at the Children's Hospital, Helsinki, and at the Aurora Hospital, Helsinki, during 1960--76. In a large proportion (37%) of the children the treatment caused pronounced side effects, and the mortality was 4.9%. The most common complications were infections: septic infections, pneumonias, and urinary and gastrointestinal infections. Other side effects were arterial hypertension (11), osteoporosis (2), hypokalaemic alkalosis (2), and other marked electrolyte disturbances (10). In children necropsy showed fresh intracerebral haemorrhages. Four children developed oliguria and hyperkalaemia during and after withdrawal of ACTH. One of them had tubular necrosis confirmed by renal biopsy. Infections were significantly more common with large doses (120 units) of ACTH than with small ones (40 units). It is concluded that side effects, even severe ones, are more common during treatment than had been assumed. Careful watch is important before and after treatment. The benefit of very high dosages should also be reconsidered.

Acute Kidney Injury↗