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Biomedical subjects

J Simon

Publications and source records attributed to J Simon.

At least 595 records · Page 33Linked to original sources
PubMed1979

Vaccinia virus infection of the central nervous system in X-irradiated mice.

The effect of X-irradiation on experimental vaccinia infection of BALB/c mice was studied. As compared with nonirradiated controls, the X-irradiated animals exhibited (i) a time lag in virus replication (delayed, but protracted replication); (ii) a delayed and repressed immune response: (iii) more severe acute cytocidal infection of leptomeninges, choroid plexus, ependyma, and vessels, with extensive damage to the brain-barrier system; and (iv) noncytocidal, latent infection of glial cells and neurons. Several animals developed acute or subacute demyelination disease, resembling experimental allergic encephalomyelitis or postinfectious encephalomyelitis.

Animals↗
PubMed1979

Myasthenia gravis: the effect of Tensilon on the caloric nystagmus response. Photoelectronystagmographic study.

The nystagmus response evoked by thermic vestibular stimulation on 25 patients with myasthenia gravis and on 10 control persons was investigated using the photoelectronystagmographic method before and after administration of Tensilon. On the basis of 19 nystagmograms (capable of being evaluated) it was found that the test is of diagnostic value when combined with abstinence from drugs, furthermore, it may indicate under- or overtreatment of patients taking drugs. Excluding the drug-resistant, "burned out" cases, a certain correlation may be observed between the magnitude of the reaction evoked by Tensilon and the severity of the clinical condition independent from the existence of ocular symptoms. The advantage of the test, apart from being numerically measurable, is that it can be repeated because of its non-invasive nature causing no physical burden to the patient. Its disadvantage is that it cannot be applied in cases with a pre-existent difference in vestibular tonus - 20% in the material tested.

Adolescent↗
PubMed1979

High fluid-low calcium intake: not all renal stone formers adhere to this simple treatment.

FActors predisposing to renal stone formation have been studied in 309 patients. Dehydration before diagnosis of urolithiasis was due in 12% of the cases to frequent diarrhea and in 36% to bad working conditions. Daily fluid intake was less than 1 liter in 25% of the patients before stone formation and was persistently low in 11% after stone discovery. 41% of the patients drank irregularly over the day, before stone formation, and 11% continued to do so after its detection. Immobilization was present in the patient's history in over 20% of the cases. Normocalcemic hypercalciuria was found in 26% of the patients. 24% of the patients drank water with a calcium concentration of 100--500 mg/l before the lithiasis was diagnosed; 21% continued to do so after stone discovery or paradoxically even drank harder water than before stone detection.

Adolescent↗
PubMed1978

Stereotaxic exploration in 200 supratentorial brain tumors. Its value in addition to computerized tomography.

The authors emphasize the advantages of stereotaxic methodology in the management of 200 brain tumors. Nowadays computerized tomography is the first stage of radiologic diagnosis. Both CT scan and stereotaxic examination have been carried out in more than 35% of these tumors. Rather than a comparison of the two examinations, the authors' purpose is to attempt to demonstrate their complementarity in the assessment of location, volume, and nature of the lesion and eventually in the choice of a therapeutic attitude. Analysis of topographic data and staged biopsies, gathered from the 'stereotaxic space,' provides the neurosurgeon with accurate information for planned surgical excision or interstitial irradiation.

Brain Neoplasms↗
PubMed1978

Effect of fasting, glucose, amino acids and food intake on in vivo insulin release in the chicken.

Insulin release was studied in vivo in the chicken using the radioimmunoassay previously described (Simon, Freychet and Rosselin 1974). An orally administered glucose load (2 g/kg b.w.) stimulated insulin release and was rapidly metabolized. A prolonged fasting period (65 hr) increased both initial plasma glucose and initial plasma insulin levels and highly impaired the glucose tolerance. A fasting-impaired insulin release and/or a fasting tissue "insulin resistance" accounted for this fasting-impaired glucose tolerance. An orally administered amino acid mixture (1 g/kg b.w.) stimulated insulin release to a very low extent. The effect was however sufficient to decrease the plasma glucose level. In combination with glucose, the oral amino acid load potentiated the effect of a dose of glucose on insulin release and highly improved the glucose tolerance. This synergism was still observed with the intake of a mixed and balanced diet. Therefore, except for some characteristics observed in the chicken which are discussed, the insulin regulation and the pancreatic beta-cell function are qualitatively similar in the chicken and in mammals.

Amino Acids↗
PubMed1978

Adenosine 5'-O-([gamma-18O]gamma-thio)triphosphate chiral at the gamma-phosphorus: stereochemical consequences of reactions catalyzed by pyruvate kinase, glycerol kinase, and hexokinase.

The 2-[18O]phosphorothioate of D-glycerate, chiral at phosphorus, was prepared. The chiral phosphoryl group was transferred enzymically to ADP [by using enolase and pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase; EC 2.7.1.40)] resulting in the synthesis of adenosine 5'-O-([gamma-18O],gamma-thio)triphosphate. This labeled ATP was used as a thiophosphoryl group donor in the reactions catalyzed by glycerol kinase (ATP:glycerol 3-phosphotransferase; EC 2.7.1.30) and by hexokinase (ATP:D-hexose 6-phosphotransferase; EC 2.7.1.1). The product from the latter (glucose 6-phosphorothioate) was converted enzymically into glycerol phosphorothioate. Determination of the relative configurations and diastereoisomeric purities of the samples of glycerol phosphorothioate demonstrates that all three phosphokinases (pyruvate kinase, glycerol kinase, and hexokinase) transfer the thiophosphoryl group with complete stereospecificity, and further shows that these reactions follow an identical stereochemical course.

Adenosine Triphosphate↗
PubMed1978

Mannitol osmolar clearance in diabetes insipidus of children.

A modified technique of amnnitol-induced diuresis is described, in order to assess renal concentrating ability in infants and children. The infusion of 10% mannitol in 0.9% saline avoided the hypertonic saline overload and the fluid restriction period, both badly tolerated by infants and small children. In a control group of children aged from two months to seven years, the values of T(H2O) plotted against C(OSM) allowed to calculate the adjustment curve y=0.80x0.75, r=0.98 (p is less than 0.0001). In six patients with pituitary diabetes insipidus (PDI), the test was used in order to quantify the degree of ADH deficiency and evaluate the carbamazepine and clofibrate effect, in the renal concentrating mechanism. The test was tolerated perfectly in every case, obtaining qualitative and quantitative data and avoiding the hyponatremia and hypokalemia produced by the mannitol.

Carbamazepine↗
PubMed1978

Chemical analysis of renal stones from 377 Belgian patients by using qualitative or quantitative methods.

The renal stones of 377 patients from the Brussels' area have been studied by chemical methods; 239 stones were submitted to qualitative analysis and the other 138 to a quantitative analysis. The results of the study demonstrate that, in Belgium as well as in other Western countries like the USA and Great Britain, calcium oxalate, calcium phosphate and magnesium ammonium phosphate are, in decreasing order of frequency, the major constitutents of renal calculi. The fact that calcium oxalate-containing stones are mainly found in men associated with sterile urine, and magnesium ammonium phosphate stones in women associated with urinary infection, is confirmed in the present series. The percentage of uric acid-containing stones is similar to that in the USA and Great Britain, but lower than that observed in several European countries including France, Spain, Germany, Czechoslovakia and Sweden. A small group of Mediterranean patients living in Belgium show no specific pattern, suggesting that the formation of calculi could be more dependent upon environmental than upon ethnic factors.

Ammonia↗