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Biomedical subjects

L Simon

Publications and source records attributed to L Simon.

At least 235 records · Page 13Linked to original sources
PubMed1981

[CRST syndrome. Ultrastructural and physico-chemical studies of calcifications (author's transl)].

The subcutaneous calcifications in a case of CRST syndrome were studied by electron microscopy and by several physico-chemical tests in order to establish their structure and development. Samples of powder, obtained by crushing and homogenisation of the deposits, were subjected to the following analyses: - radiocrystallography by X-ray of the raw and heated material - infra-red spectroscopy before and after heating - quantitative chemical analysis and differential thermal micro-analysis. Connective tissue fibres seemed to play an important part in the development of the calcifications. The initial deposits of calcium first appeared in the central part of elastic fibres whose general morphology remained nevertheless undisturbed. In the older deposits disorganised elastic (and possibly collagen) fibres and areas of bone formation were found. Evidence of an inflammatory reaction was always minimal or nil. There was considerable variation in the calibre of collagen fibres in the non-calcified zones, the smaller fibres predominating. These appearances, sometimes noted in scleroderma, seem to be associated with increased collagen synthesis. X-ray diffraction and infra-red spectroscopy studies show that the deposits consist essentially of type B hydroxyapatite carbonate, confirmed by differential thermic analysis. On electron microscopy the calcifications were shown to comprise straight, needle-like crystals, 100-600 nm in length and 30-100 nm broad, characteristic of the apatites. Very occasionally, target-pattern deposits conforming to whitlockite were encountered. Chemical analysis revealed a high proportion of calcium with a Ca/P ratio greater than 1-666 as is typical of synthetic hydroxyapatite carbonates. The deposits also contained up to 20% by weight of organic material.

Adult↗
PubMed1980

Individual differences in diurnal rhythms and multiple activation states: a reply to M. W. Eysenck and Folkard.

Three issues raised by M. W. Eysenck and Folkard are discussed. These include (a) just what individual difference variable is mediating the time of day and caffeine effects; (b) what the difference is in the diurnal rhythms of low and high impulsives; and (c) whether it is necessary to postulate multiple activation states. Suggestions for future research are then given.

Arousal↗
PubMed1980

Atrophic gastritis and intestinal metaplasia in asymptomatic Hungarian and Italian populations.

The histological patterns of the gastric mucosa obtained by endoscopic biopsy were evaluated in two different ethnic groups, each containing one hundred patients without gastro-intestinal diseases. The incidence of atrophic gastritis and intestinal metaplasia increased with age in both groups, revealing a statistically significant difference above 60 years. The comparative study of gastric cancer death rates in the two population groups showed a significant prevalence in the Hungarians above 50 years. This fact seems to support the hypothesis that an ethnic group with high gastric cancer rate has a higher prevalence of atrophic gastritis and intestinal metaplasia in the older age groups, and offers additional evidence for the association of chronic inflammatory changes of the gastric mucosa with malignant gastric cancer.

Adult↗
PubMed1980

The interactive effect of personality, time of day, and caffeine: a test of the arousal model.

The personality dimension of introversion/extraversion is one of the few personality dimensions that can be reliably identified from study to study and investigator to investigator. The importance of this demension within personality theory is due both to the stability of the trait and the influential theory of H. J. Eysenck. The basic assumption in Eysenck's theory of introversion/extraversion is that the personality differences between introverts and extraverts reflect some basic difference in the resting level of cortical arousal or activation. Assuming that there is a curvilinear relationship (an inverted U) between levels of stress and performance leads to a test of this arousal theory. That is, moderate increases in stress should hinder the performance of introverts who are presumably already highly aroused. However, the same moderate increase in stress might help the performance of the presumably underaroused extraverts. Revelle, Amaral, and Turriff reported that the administration of moderate doses of caffeine hindered the performance of introverts and helped the performance of extraverts on a cognitive task similar to the verbal test of the Graduate Record Examination. Assuming that caffeine increases arousal, this interaction between introversion/extraversion and drug condition supports Eysenck's theory. This interaction was explored in a series of experiments designed to replicate, extend, and test the generality of the original finding. The interaction between personality and drug condition was replicated and extended to additional cognitive performance tasks. However, these interactions were affected by time of day and stage of practice, and the subscales of introversion/extraversion, impulsivity, and sociability, were differentially affected. In the morning of the first day, low impulsives were hindered and high impulsives helped by caffeine. This pattern reversed in the evening of the first day, and it reversed again in the evening of Day 2. We concluded that the results from the first day of testing require a revision of Eysenck's theory. Instead of a stable difference in arousal between low and high impulsives, it appeared that these groups differed in the phase of their diurnal arousal rhythms. The result is that low impulsives are more aroused in the morning and less aroused in the evening than are the high impulsives. A variety of peripheral or strategic explanations (differences in caffeine consumption, guessing strategies, distraction, etc.) for the observed performance increments and decrements were proposed and tentatively rejected. It seems probable that some fundamental change in the efficiency with which information is processes is responsible for these performance changes.

Arousal↗
PubMed1980

[Lumbar intraspinal tumors seen in a rheumatological context].

On the basis of a 50 case study, the authors insist on the difficulty of diagnosing lumbar intraspinal tumors seen in a rheumatological context. The increase in pain and spine and spine stiffness at night are the most significant semiological characteristics. A generally slight neurological deficiency is noted in 29 cases (58%) and 21 patients (41%) have a clinical picture identical to that of discal hernias. X-rays of the lumbar spine show signs of bone erosion in 24% of cases. Lumbar puncture furnishes major indications in 85.5% of cases. Contrast testing almost always demonstrates the presence of a tumor. Lumbar intraspinal tumors include a very wide variety of histological types, among which neurinomas, ependymomas and extra-dural malignant tumors are the most frequent.

Adolescent↗
PubMed1980

[The rheumatoid foot. Origin of deformations].

Deformations of the foot are a logical and predictable function of the biomechanics of the foot and the constraints undergone by the articulations of the foot, that are unstabilized by the inflammatory process. They result from the combination of three factors : anevolutive teno-articular synovitis, predictible forces (the weight of the extrinsic muscle, the anti-physiological foot), and the congenital morphotype of the foot. Typical deformations (peroneal " coup de vent " of the toes, triangular metatarsus), differ on the clinical level in keeping with the morphotype but respond to the same mechanism. The " coup de vent peronier " remains the most characteristic deformation and is furthered by the excentric action of the extrinsic muscles, and in particular the foot muscle. The common denomination of deformations of the back part of the foot is represented by the valgus calcanean, linked to the action of the weight on the orsion forces that is more or less modified. A better knowledge of the cause of these deformations would make it possible to avoid, if not their apparition, at least their worsening.

Adult↗
PubMed1980

[Value of successive chemotherapy in multiple myeloma of bone. Prospective study over 4 years].

In order to study the response of patients with multiple myeloma of the bones (MM) to various anti-cancer drugs (Melphalan M, Cyclophosphamide Cy, Nitrosourea NU, Vincristine V, Adriamycine A and Prednisone P), 70 MM received the following treatment : 1) Induction therapy : a) M and P or b) M and Cy and P ; 2) Levelling with partial or complete response : V Cy P (in case a) or V M Cy P (in case b) ; 3) Relapse : A and NU. The following results were obtained : 1) Only 42.6% of patients respond to induction therapy ; 2) Fewer than 10% of patients showing a response reach a second levelling with Vincristine ; 3) 50% of those not showing a response reach a levelling between --20 and --50 and have prolonged survival ; 4) Only 20% of non responders are improved by Cy P or A and NU. The median actuarial survival is 42 months. Among the responders two poor prognosis factors must be underlined : hypercalcemia and the speed of response.

Aged↗
PubMed1980

PGE2, PGF2 alpha, and TXB2 biosynthesis by human rheumatoid synovia.

Prostaglandins (PG) are currently suspected to be involved in human rheumatoid arthritis (RA). We have studied the PG [PGE2, PGF2 alpha, and Thromboxane B2 (TXB2)] biosynthesis capacity of normal (from amputations) and pathologic (osteoarthritis (OA) and RA) synovia. The measurement is done on the whole homogenate and microsomal fraction after 40 min incubation, without exogenous arachidonic acid (AA) or with a saturating concentration (25 micrograms/ml) of this compound, using a radioimmunoassay method. There is a considerable increase in PGE2 and PGF2 alpha production by the rheumatoid synovia and more PGE2 and PGF2 alpha are formed. This production is more marked for homogenates than microsomal fraction. The OA group is not homogeneous and does not differ significantly either from normals or from RA. The addition of AA considerably increases the biosynthesis of PG in both normal and pathologic tissue. For TXB2, the first results (four synovia) show no or a small biosynthesis in RA as well as in normals. Nevertheless, the levels before incubation seem higher in RA than in normal tissue.

Arachidonic Acids↗
PubMed1980

[Meralgia paresthetica: an uncommon entrapment neuropathy (author's transl)].

Meralgia paresthetica although it does not produce intensive pain is a cause of chronic disability, usually barely improved by medical treatment. From the report of two cases of neurolysis the authors stress on the possibility of entrapment neuropathy of the lateral femoral cutaneous nerve in its way through the femoral canal, between the inguinal ligament and the fascia-iliaca. Anatomically, there is in this canal a normal right angle between the horizontal portion (abdominopelvic) and the vertical course in the thigh. The compression is due to a thickening of the fascia-iliaca as it forms the postero inferior wall of this canal; the nerve is squeezed between the fascia and the inguinal ligament. In 60% of cases of meralgia paresthetica where this mechanism is involved, the funicular neurolysis appears to be a radical treatment.

Adult↗
PubMed1979

Rehabilitation of the rheumatoid shoulder.

In the treatment of the rheumatoid shoulder physiotherapy allows the use of positions relieving the joint of discomfort and preventing deformities. Isometric contractions prevent muscular atrophy. An individual programme of gentle, progressive assisted mobilization permits the total rapid recovery of painful stiffness in simple synovitis and partial recovery of painful stiffness in simple synovitis and partial recovery in the more advanced arthritic lesions. Occupational therapy techniques are proposed to complete the effect of physiotherapy at a means of adapting the patient to the difficulties encountered in daily living.

Activities of Daily Living↗