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Biomedical subjects

D Engel

Publications and source records attributed to D Engel.

At least 73 records · Page 4Linked to original sources
PubMed1980

In vitro expression of immunoglobulin M and G subclasses by murine B lymphocytes in response to a polyclonal activator from Actinomyces.

A cell wall extract from the gram-positive bacterium Actinomyces viscosus contains the mitogen AVIS, a potent polyclonal B-cell activator for murine B lymphocytes. Cultures of splenocytes from heterozygous nude mice in the presence of an optimal concentration of AVIS responded by a deoxyribonucleic acid synthesis response, and proliferaction reached maximal levels after 3 to 4 days. There was no requirement for T cells in the deoxyribonucleic acid synthesis, proliferactive, immunoglobulin M (IgM), or IgG responses. Significant numbers of IgM-producing cells were present as early as day 2 of culture, whereas later in the culture periods (days 3 to 6) IgG-producing plasmablasts and plasma cell were observed. In cultures of splenocytes from nude mice stimulated with AVIS for 4 to 5 days, 20 to 25% of the recoverable cells synthesized IgM, and 10% contained only IgG2 or IgG3; 5 to 8% of the cells stained for both IgM and IgG2 or both IgM and IgG3. Fine-structure analysis of AVIS-stimulated splenocytes from heterozygous nude mice after 3 days of culture demonstrated that 20 to 25% of the cells were activated to various degrees. Of most importance, all of the activated cells had the characteristic of B lymphoblasts, plasmablasts, or plasma cells. This is the first demonstration of a polyclonal B-cell activator other than lipopolysaccharide which induces IgG3 synthesis. We suggest that AVIS may be a useful probe for the exploration of the functional activities of subpopulations of B cells.

Actinomyces↗
PubMed1979

The effects of intra-arterially administered histamine on vascular permeability.

The influence of intra-arterially administered histamine on the permeability of the articular barrier (synovial membrane plus vascular endothelium) was studied in cats. The dye penetration from the blood through the barrier was tested by perfusing the two knee joints with saline; the histamine solution was infused through one of the circumflex branches of the femoral artery. The dye content of the two perfusates was measured colorimetrically, the local blood supply of the two knee joints thermo-electrically. In the great majority of experiments it was found that the dye excretion was considerably reduced on the histamine-infused side, in spite of marked improvement of blood supply.

Animals↗
PubMed1979

The gastroauricular phenomenon and related vagus reflexes.

Eight lesser known reflexes were grouped together because of their anatomical and physiological relationship. In all of them a branch of the vagus nerve forms a bridge between a circumscribed area of the skin, mostly the external auditory meatus, and an internal organ, namely the stomach, esophagus, lungs, heart, uterus, and some male and female sex organs. The eight reflexes are: (1) Gastroauricular phenomenon (Gaph) (Engel, 1922) in man; (2) Auricular phenomenon (Malherbe, 1958) in man; (3) Pulmonoauricular phenomenon (Deutsch, 1919) in man; (4) Auriculogenital reflex (Bradford, 1937) in cat; (5) Auriculouterine reflex (Vasiliu, 1932) in women; (6) Oculocardiac reflex (Aschner, 1967) in man; (7) Kalchschmidt's reflex in cattle (1956); and (8) Coughing attack with heartburn (Berlin, 1959) in man. The organs involved are either effector or receptor organs. The six reflexes observed in man are of diagnostic significance. Attention is also drawn to analogous reflexes in which the meningeal branch of the vagus is involved.

Animals↗
PubMed1979

The vaginal influx and its significance in the diagnosis of infections of the urinary tract.

The vaginal influx during miction is a frequent phenomenon. In our clinical study it showed a rate of 54 per cent. The significance of pathomorphological substrates is diminishing with the advancing vesical descensus. The posture during miction has but little influence on the vaginal deviation of the urinary stream. The mid-stream urine is relevantly contaminated in every other girl and, therefore, it may be used only for screening. Indication for an antibacterial therapy is based on catheter or puncture urine.

Adolescent↗
PubMed1979

A cat model for the evaluation of mechanisms of bone resorption: induction of bone loss by simulated immune complexes and inhibition by indomethacin.

When simulated immune complexes (SIC) (heat-aggregated IgG) possessing many of the properties of true antigen-antibody complexes were injected via the root canal into the periapical tissues of cat maxillary cuspids, radiographically and histologically evident bone resorption occurred at these sites within 7 days. Bone loss was accompanied in all cases by inflammation of the surrounding collagenous connective tissues and was characterized by the presence of osteoclasts. Bone resorption, but not the accumulation of inflammatory cells, was blocked by the systemic administration of indomethacin, an inhibitor of prostaglandin synthetase. The most likely explanation is that SIC-activated mechanisms such as the complement cascade, prostaglandin synthesis, and neutrophil degranulation were responsible for the bone loss. The minor inflammation and bone loss that followed the repeated injections of BSA and of monomeric IgG can best be explained as a response to trauma. The data presented establish that the cat maxillary cuspid is a useful model in which to explore the mechanism underlying pathological bone resorption.

Animals↗
PubMed1979

The significance of leucocytosis in the X-irradiated tumour-bed.

(1) Present experiments confirm previous studies (Beck and Engel[1], 1927) according to which a tumour implanted s.c. into an X-irradiated area of mice is inhibited in its growth by 50 to 66% as compared with the implant of the nonirradiated side of the same animal. In the present series the growth inhibition amounted to practically 50%. (2) Exposure of the mouse skin to X-radiation caused a marked hyperleucocytosis within the first 24 hours, with a rapid decrease to normal levels within 4 or 5 days. (3) The inhibitory effect of X-radiation on the tumour growth and the inflammatory response of the skin (leucocyte count) did not run a parallel course except during the first few days after irradiation. The conclusion is drawn that hyperleucocytosis of the tumour bed is not the only cause for the tumour growth inhibition.

Animals↗
PubMed1978

The influence of the sympathetic nervous system on capillary permeability.

1. The influence of the sympathetic nervous system on capillary permeability was studied in cats. The dye penetration from the blood through the synovial membrane was tested by perfusing the two knee joints, one of which was deprived of its sympathetic nerve supply by unilateral lumbosacral sympathectomy. 2. In confirmation of previous experiments, it was found in a great majority of experiments that, in spite of marked vasodilatation, the dye excretion was considerably reduced on the sympathectomised side. 3. A large amount of experimental evidence, supporting directly or indirectly, my views, has been reviewed. 4. A permeability factor under the influence of the sympathetic nervous system has been postulated; its character and mechanism is still unknown. 5. Further unpublished experiments seem to support the view that increased blood supply is associated with decreased vascular permeability.

Animals↗
PubMed1978

Morphological features and functional properties of human fibroblasts exposed to Actinomyces viscosus substances.

Connective tissue fibroblasts undergo cytopathic degenerative changes during certain long-term inflammatory diseases such as rheumatoid arthritis and periodontitis. The failure of inflamed tissues to repair properly may result from functional alterations of fibroblasts within the affected tissues. Numerous previous studies indicate that direct cytotoxicity by bacterial or other substances may be responsible for the cellular alterations observed in vivo. We have tested this hypothesis by exposing cultures of human diploid fibroblasts to homogenates of Actinomyces viscosus (a microorganism associated with periodontitis and capable of causing other chronic inflammatory diseases) and analyzing the effects on cell viability, morphology, and function. The cells bind and subsequently engulf relatively large quantities of the bacterial substances. These substances do not appear to be toxic to fibroblasts as determined by 51Cr release and microcytotoxicity assays, although there is a slight but significant decrease in protein synthesis (P less than 0.01) as measured by the incorporation of [14C]proline. However, collagen production was not altered, and the cytopathic alterations observed in diseased tissues in vivo did not occur in the exposed cells. These findings suggest that A. viscosus substances do not directly cause injury to connective tissue fibroblasts in periodontal disease but may, through cell-surface binding, mark these cells for subsequent immune-mediated damage.

Actinomyces↗
PubMed1978

[Late results following palliative vascular embolization in inoperable kidney tumors. (Preliminary report)].

During 18 months in 15 patients with inoperable renal tumours palliative therapeutic vascular embolisations were carried out with the help of an own catheter technique. In contrast to preoperative embolisation (16 patients) in the inoperable cases a non-absorpable polyvinyl alcohol foam substance ("Ivalon") was used, which leads to a secure permanent vascular occlusion. The haematuria occurring in all patients which many times threateningly increased was removed in all cases. There did not appear any essential complications. However, on account of the formation of a symptomatology of renal infarction a clinical after-treatment is necessary. In 12 patients regulary clinical and paraclinical control examinations during an observation period of on an average 11 months were carried out (minimum 6 months, maximum 18 months). 11 of these patients were still alive at the end of the report and had a tolerable or even improved general condition. In angiographical after-controls of 4 patients, and in one case by autopsy, permanent vascular occlusions with formation of necroses of a large area and partly considerable restriction of the tumour kidneys were found. In these cases the therapeutic embolisation led to a provable damage of the tumorous process. An influence of metastases distant from the primary tumour was not observed.

Embolization, Therapeutic↗
PubMed1977

The conceptual structure of aphasic and schizophrenic patients in a nonverbal sorting task.

Hierarchical and overlapping cluster methods were applied to the sortings of aphasic, nonaphasic brain-damaged, schizophrenic, and normal subjects presented with 30 pictures of animals. The hierarchical structure solutions were most diffuse for the groups of the schizophrenics and the fluent aphasics'. The structure for the nonfluent aphasics showed more clarity, but was also deviant from the structures of the normals and the brain-damaged without aphasia. Fluent aphasics but not nonfluent aphasics tended to sort pictures which they could not name into smaller groups. For the nonfluent aphasics, there was a significant correlation between the commonality of the sortings and the severity of aphasic disturbances as measured by the Token Test. The relationship between conceptual disorganization and language impairment seems to be functionally different for fluent and nonfluent aphasics.

Adolescent↗
PubMed1977

Intra-arterial basie dye studies of the blood-CSF and blood-brain barriers.

1. The permeability of the blood-CSF barrier was tested by injecting highly diffusible basic dyes into the common carotid artery and aspiration of the cisterna magna during or shortly after the injection. None of the dyes appeared in the CSF. 2. The appearance of similarly administered basic dyes were observed in the exposed cerebral cortex. Some of the basic dyes appeared in the cortex immediately after a few drops of dye were injected. This contradicts the assumption that staining of the brain by basic dyes is a post-vital process. 3. The difference between the permeability of the blood-CSF barrier and the blood-brain barrier proves the fundamentally different characters of the two barriers.

Animals↗