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Biomedical subjects

L Simon

Publications and source records attributed to L Simon.

At least 19 recordsLinked to original sources
PubMed1992

Evolutionary relationships within the fungi: analyses of nuclear small subunit rRNA sequences.

Nucleotide sequences of the small subunit ribosomal RNA (18S) gene were used to investigate evolutionary relationships within the Fungi. The inferred tree topologies are in general agreement with traditional classifications in the following ways: (1) the Chytridiomycota and Zygomycota appear to be basal groups within the Fungi. (2) The Ascomycota and Basidiomycota are a derived monophyletic group. (3) Relationships within the Ascomycota are concordant with traditional orders and divide the hemi- and euascomycetes into distinct lineages. (4) The Basidiomycota is divided between the holobasidiomycetes and phragmobasidiomycetes. Conflicts with traditional classification were limited to weakly supported branches of the tree. Strongly supported relationships were robust to minor changes in alignment, method of analysis, and various weighting schemes. Weighting, either of transversions or by site, did not convincingly improve the status of poorly supported portions of the tree. The rate of variation at particular sites does not appear to be independent of lineage, suggesting that covariation of sites may be an important phenomenon in these genes.

Animals↗
PubMed1992

Terror management and tolerance: does mortality salience always intensify negative reactions to others who threaten one's worldview?

Terror management research has shown that reminding Ss of their mortality leads to intolerance. The present research assessed whether mortality salience would lead to increased intolerance when the value of tolerance is highly accessible. In Study 1, given that liberals value tolerance more than conservatives, it was hypothesized that with mortality salience, dislike of dissimilar others would increase among conservatives but decrease among liberals. Liberal and conservative Ss were induced to think about their own mortality or a neutral topic and then were asked to evaluate 2 target persons, 1 liberal, the other conservative. Ss' evaluations of the targets supported these hypotheses. In Study 2, the value of tolerance was primed for half the Ss and, under mortality-salient or control conditions, Ss evaluated a target person who criticized the United States. Mortality salience did not lead to negative reactions to the critic when the value of tolerance was highly accessible.

Attitude to Death↗
PubMed1992

Why do people need self-esteem? Converging evidence that self-esteem serves an anxiety-buffering function.

Three studies were conducted to assess the proposition that self-esteem serves an anxiety-buffering function. In Study 1, it was hypothesized that raising self-esteem would reduce anxiety in response to vivid images of death. In support of this hypothesis, Ss who received positive personality feedback reported less anxiety in response to a video about death than did neutral feedback Ss. In Studies 2 and 3, it was hypothesized that increasing self-esteem would reduce anxiety among individuals anticipating painful shock. Consistent with this hypothesis, both success and positive personality feedback reduced Ss' physiological arousal in response to subsequent threat of shock. Thus, converging evidence of an anxiety-buffering function of self-esteem was obtained.

Adaptation, Psychological↗
PubMed1992

Rapid quantitation by PCR of endomycorrhizal fungi colonizing roots.

The VANS1/NS21 primer pair is useful for specifically amplifying a 550-bp ribosomal (r) DNA fragment from arbuscular endomycorrhizal fungi, directly from colonized root extracts. A procedure to quantitate these obligatory biotrophs rapidly, based on competitive PCR, was developed by constructing a suitable internal standard to be used with these primers. A 130-bp deletion in the Glomus mossae VANS1/NS21 amplified rDNA fragment was produced by amplifying separately external portions of that fragment, followed by ligation and amplification using the original external primers. When this deleted fragment was added to G. mossae rDNA, amplification using VANS1/NS21 primers yielded the two expected products of 430 bp and 550 bp, respectively, resolved by agarose electrophoresis. This fragment was cloned into the pCL1920 plasmid, a low-copy-number vector (five copies per cell), and mixed with the roots to be analyzed. This provides for a rapid quantitative assay because both steps--extraction of DNA from colonized roots and PCR amplification--are taken into account by the same internal standard. Using this procedure, a sample of colonized leek roots (Allium porum x Glomus vesiculiferum) was shown to contain 5 x 10(4) copies of arbuscular endomycorrhizal fungi rDNA genes per milligram of fresh weight.

Allium↗
PubMed1992

Specific amplification of 18S fungal ribosomal genes from vesicular-arbuscular endomycorrhizal fungi colonizing roots.

The first DNA sequences obtained from arbuscular endomycorrhizal fungi are reported. They were obtained by directly sequencing overlapping amplified fragments of the nuclear genes coding for the small subunit rRNA. These sequences were used to develop a polymerase chain reaction primer (VANS1) that enables the specific amplification of a portion of the vesicular-arbuscular endomycorrhizal fungus small subunit rRNA directly from a mixture of plant and fungal tissues. The specificity of this primer for arbuscular endomycorrhizal fungi was demonstrated by testing it on a number of organisms and by sequencing the fragment amplified from colonized leek (Allium porum) roots. This approach, coupled with other molecular techniques, will facilitate rapid detection, identification, and possibly quantitation of arbuscular endomycorrhizal fungi.

Allium↗
PubMed1992

Esophageal mucosal protection--why do we need a special approach?

The epidemiology and natural history of reflux induced peptic esophageal diseases remain incompletely understood. That is why it is easy to explain that the traditional therapeutic efforts were mostly restricted to the use of acid-reducing or neutralizing drogs. The author tries to survey--mainly on theoretical bases--a new approach of the maintenance treatment of peptic esophagitis and consequential columnar metaplasia. The mechanism of the esophageal antireflux barrier is composed by the (a) lower esophageal sphincter tone, (b) upper esophageal sphincter tone, (c) esophageal acid clearance and (d) esophageal epithelial resistance. The data of a 100-patient-group of gastroesophageal reflux disease cases were retrospectively evaluated principally considering the efficacy of antisecretory treatment relating to the accompanying diseases, recurrence of symptoms and prevention the development of Barrett's columnar lined esophagus and Barrett's ulceration. The decrease of exposure by damaging factors is an essential criterion of antisecretory therapy, having several disadvantages. Based only to logically well established arguments the author believes that gastroesophageal reflux disease and consecutive conditions might be an ideal model for studying and introducing esophageal cyto (-mucosal, -tissue) protection, considering that in the esophagus--in contradiction to the stomach--the cell and tissue injury, induced by several pathogenic agents, does not develop rapidly, and when the organ damage develops gradually, interventions may be possible to protect esophageal cell and the mucosa directly.

Barrett Esophagus↗
PubMed1992

[Severe hypocalcemia complicating outbreaks of renal failure in 2 uremic patients].

Hypocalcemia has many causes of which several often occur in combination in intensive care unit patients. Two cases (a 78-year-old male and a 63-year-old female) of severe hypocalcemia (corrected serum calcium 1.2 mmol/l in both cases) in patients hospitalized for acute decompensation of chronic renal failure are reported herein. Both subjects had a history of chronic hypocalcemia due to vitamin-calcium deficiencies and chronic renal failure. The lack of adverse clinical consequences of the low serum calcium levels can be explained by the fact that both patients also had severe metabolic acidosis, a disorder which increased the ionized fraction of total serum calcium. Serum calcium returned to normal slowly and gradually despite parenteral administration of large amounts of calcium and vitamin D or vitamin D derivatives.

Aged↗
PubMed1991

[Lumbar disk herniation with no surgical treatment. Clinical and x-ray computed tomographic follow-up study].

The authors have studied the clinical and computed tomographic (CT) follow-up of 50 patients with nerve root symptoms and herniated nucleus pulposus (HNP) who received only a conservative medical treatment. The clinical follow-up showed that after 23 months 38 patients (76 percent) did not require surgery and 63 percent of these had good or very good results. Follow-up CT scans, performed in 20 patients, found spontaneous disappearance of NP in 10 cases and partial regression in 3 cases. Several mechanisms may explain this regression, including fragmentation and sequestration of the disc fragment, dehydration and shrinkage of the HNP and its reintegration into the annulus. On the other hand, HNP persisted in some patients who had become asymptomatic, and it was also found in an asymptomatic control subject. These data demonstrate that clinical and CT findings may be dissociated. Not all CT scan-documented HNPs require interventional therapy. Except in case of emergency, surgical treatment should be considered only after failure of conservative medical treatment and whenever clinical and CT data are concordant. CT and other imaging procedures, such as myelography and nuclear magnetic resonance, should only be used preoperatively in patients with appropriate clinical findings.

Adult↗
PubMed1991

Large-scale preparation of a highly purified solvent-detergent treated factor VIII concentrate.

Large-scale adaptation of a recently reported glycine precipitation method for the production of factor VIII (FVIII) concentrate is described. Scaling up of the method required some modification including the addition of aluminum hydroxide to the glycine buffer to reduce the level of contaminating proteins in the final preparation and the use of centrifugation to replace filtration by glass beads. Furthermore, the resultant product was virus inactivated by incorporation of the organic solvent and detergent technique. At industrial level, the modified method gave a good recovery of FVIII activity (230 IU/l plasma) with high purity (4 IU/mg protein). The final product, after virus inactivation and lyophilization, yielded 185 IU of FVIII activity per liter of starting plasma and was considered to be suitable for clinical evaluation.

Detergents↗
PubMed1991

[Hip and spinal ossification enthesopathies induced by etretinate therapy in peripheral psoriatic arthritis].

The occurrence of ossifying enthesopathy during treatment with synthetic retinoids (etretinate, isotretinoin and acitretin) is a side-effect more and more frequently recorded. The authors report here a new case in a patient with a severe psoriatic arthritis. This observation is characterized by the size of ossifications on hips and lumbar spine which appeared after two years of etretinate therapy. The interest of this observation lies in the fact that ossifications occurred while the patient was treated with long-term corticotherapy. The disease for which retinoids are prescribed does not seem to influence the occurrence of those lesions and it is likely that the responsibility of these molecules is entire. Lesions are enthesitis ossification. They are frequent during these treatments (average of 70%) after an average time of 24 to 36 months for etretinate and of 10 months for isotretinoin. Lesions are asymptomatic in about 50% of the cases. After discontinuation of treatment, lesions become quiescent and does not disappear. Growth hormone or abnormalities in vitamin A metabolism could play a role in the physiopathology of lesions.

Arthritis, Psoriatic↗
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↗
PubMed1979

[Prostatic osteosis. Retrospective study of 110 cases treated with high-dose estrogens].

On the basis of 110 prostatic osteoses that were histologically proven, constantly painful and demonstrated by X-ray, treated by early estrogenotherapy using very high doses, backed up by a high-dose maintenance estrogenotherapy, the authors study the clinical, radiological, histological and biological profile of this metastatic cancer, as well as the response to treatment. The median actuarial survival time of the patients studied is 18.5 months. No statistically significant prognostic correlation was found. Only patients who are clinically estrogen-sensitive, are suffering from bone metastases without a combined visceral conditions, and have a normal initial rate of alcaline phosphates, tend to have a better prognosis (median actuarial survival 31 months versus 18.5 months for the overall population).

Adult↗
PubMed1979

[Multiple myeloma of bones. Retrospective study of prognostic factors based on a series of 243 patients].

The authors have made a retrospective study of 243 cases of multiple myelomas, most of them treated with alkylating agents. The average age at the time of diagnosis was 65 years (+ 10). The ratio of the sexes was 1 : 1. Seventy two per cent of the patients had a bone rating of 2 or 3 according to the criteria of Durie and Salmon. Fifty-eight per cent of the patients were anemic (Hg 12 g per cent), with less than 15 per cent being leucopenic or thrombopenic. Hypercalcemia (105 mg 0/00) was noted in 27 per cent of cases. The distribution of immunochemical types is as follows : IgG, 51.5 per cent; IgA, 28 per cent; pure Bence Jones, 20.5 per cent. The respective percentages of kappa and lambda light chains were 64.2 per cent and 35.8 per cent. In this series, nearly 80 per cent of the patients were at phase III according to the classification of Durie and Salmon, and 30.8 per cent at phase B. The median survival, including all phases, increased from 8 months without alkylating agent, to 20 months with melphalan and/or cyclophosphamide. The factors influencing the survival of the patients treated were age, the hemoglobin level, calcemia, renal deficiencies, the immunochemical type, the stage of the disease, and the response to alkylating treatment. The value of these different prognostic factors is discussed.

Adult↗