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Biomedical subjects

M Simon

Publications and source records attributed to M Simon.

At least 415 records · Page 23Linked to original sources
PubMed1989

Cryopreserved 3T3 fibroblasts retain their capacity to enhance the growth of human keratinocyte cultures.

Cultured epithelial grafting of full-thickness skin defects is a new promising possibility for the successful treatment of patients with large burns. The major obstacle to this method, however, is a 3-4-week interval between burn and grafting, which is necessary for the growth of sufficient quantities of cultured epithelium. Generally, growth-arrested murine 3T3 fibroblasts have been used with success as feeder layers to shorten the cultivation time of keratinocytes. In the present work we have initiated studies to determine whether or not cryopreserved growth-arrested 3T3 fibroblasts retain their capacity to enhance the growth of human keratinocytes in vitro. The results of this study show that the [3H]thymidine incorporation in cultures containing mitomycin C treated 3T3 feeder cells was significantly greater than in cultures without feeder cells. Furthermore, in keratinocyte cultures containing freshly separated or cryopreserved 3T3 fibroblasts, a similar rate of [3H]thymidine incorporation was observed and the activity of incorporation has never differed significantly during the 11 days of culturing, meaning that cryopreserved, growth-arrested 3T3 fibroblasts retain their ability to enhance the growth of human keratinocytes. This observation renders the continuous maintenance of 3T3 cells unnecessary in laboratories which want to culture keratinocytes without delay.

Animals↗
PubMed1989

[Use of medicaments in endodontic treatment].

An overview is given of the use and misuse of medicaments during endodontic treatment. The use of formaldehyde containing products in endodontics should be avoided. Sodium hypochlorite is the medicament of choice for irrigation and disinfection of the root canal, while calcium hydroxide is advised as inter-appointment root canal medication. There is no need for root filling materials with medicaments like paraformaldehyde and corticosteroids.

Adrenal Cortex Hormones↗
PubMed1989

[Crohn disease--initial manifestation in the oral and anogenital area].

A case is reported of Crohn's disease in a 17-year-old patient. The initial manifestation was bipolar: the clinical features of macrocheilitis with swelling of the upper lip that had persisted for the last 6 months. The buccal tissue disclosed a cobblestone-appearance, combined with atypical fissures and rhagades in the anogenital region. Histopathological examination of lip and anogenital biopsy specimens revealed a granulomatous inflammatory reaction. Therefore, the clinical findings were interpreted as the primary manifestation of Crohn's disease. In the differential diagnosis Melkersson-Rosenthal's syndrome was also taken into consideration.

Adolescent↗
PubMed1988

The glutamine residues reactive in transglutaminase-catalyzed cross-linking of involucrin.

The protein involucrin, synthesized by human keratinocytes, contains 585 amino acids, largely in the form of 10 amino acid repeats, each containing glutamines in 3 conserved positions. Involucrin is a substrate for the keratinocyte transglutaminase and is labeled by the cosubstrate amine, glycine ethyl ester. Study of tryptic peptides of involucrin shows that a single glutamine (residue 496), located 89 residues from the C-terminal end, is preferentially labeled by the enzyme. Additional glutamine residues become reactive when the molecule is fragmented. The C-terminal end, isolated as a cyanogen bromide fragment of 275 residues, is labeled equally at 2 glutamine residues. The polypeptide containing residues 148 to 280 accepts practically no amine while in intact involucrin but as a free fragment is labeled at multiple glutamine residues. It is concluded that the C-terminal and N-terminal ends of the protein are directive influences in that they suppress the reactivity of a number of glutamine residues in the intact molecule, leaving one glutamine highly preferred by the transglutaminase.

Amino Acid Sequence↗
PubMed1988

[Influence of pregnancy on the development of Hodgkin's disease].

This retrospective study concerns 13 patients in whom Hodgkin's disease was diagnosed during pregnancy or immediately after delivery (group I) and 12 patients with Hodgkin's disease who had one or several pregnancies while under treatment (group II). In group I, Hodgkin's disease was diagnosed in early pregnancy in 4 patients who all had therapeutic abortion: 3 remain in prolonged complete remission and 1 had a late relapse; 9 cases were diagnosed in late pregnancy or after delivery: 3 were treatment failures, 2 had a relapse and 4 remain in complete remission. In group II patients, 3 pregnancies occurred during initial chemotherapy and were interrupted; 5 pregnancies occurred during subsequent radiotherapy or (for earlier patients) maintenance chemotherapy, and 4 of them were interrupted; 9 pregnancies occurred within 2 years of completing treatment, and 7 after 2 years. Of the 12 patients in group II, only 2 had a relapse whereas 10 remain in complete remission. Although they should be interpreted with caution, these data suggest that Hodgkin's disease diagnosed in late pregnancy or after delivery might be more active, and they justify therapeutic abortion when diagnosis is made in early pregnancy. They do not indicate a high risk of relapse in treated Hodgkin's disease patients during a subsequent pregnancy, even if it occurs shortly after treatment.

Abortion, Therapeutic↗
PubMed1988

Labial adhesions and posterior fourchette injuries in childhood sexual abuse.

Six cases involving six sisters, all of whom were sexually molested, are presented to illustrate the association between labial adhesions and posterior fourchette injuries in sexually abused children. Although labial adhesions are a relatively common lesion, they only recently have been associated with childhood sexual abuse. Labial adhesions are ordinarily found in girls between 2 months and 7 years of age and are usually very superficial and disappear spontaneously by the time the child approaches puberty. We encountered six sisters, all of whom had been sexually abused, who had labial adhesions. Four of the six had changes in the area of the posterior fourchette that were consistent with previous trauma. In addition, four of the girls' hymens had thickened, irregular edges or other changes that were considered abnormal. The father, the grandfather, and an uncle confessed to lewd and lascivious misconduct with the children. Although labial adhesions alone are not reason enough to make a report of sexual abuse, the physician is obligated to inquire as to the possible cause if the adhesions do not fit the usual pattern or if there are other suspicious findings.

Child↗
PubMed1988

MSS18, a yeast nuclear gene involved in the splicing of intron aI5 beta of the mitochondrial cox1 transcript.

We have isolated and characterized a nuclear gene, MSS18, which is implicated in the splicing of intron aI5 beta of the mitochondrial cox1 transcript (subunit 1 of the cytochrome c oxidase). Northern blotting and S1 nuclease protection experiments as well as the analysis of mitochondrial point revertants suggest that mss18 mutations block (perhaps indirectly) the cleavage of the 5' exon-intron junction of aI5 beta. Mitochondrial point revertants also indicate that up to 13 bases of the aI5 beta exon sequence, upstream of the 5' splice site of aI5 beta, are involved in vivo in the splicing of this intron. The implications of this result on the splicing of group I introns are discussed.

Amino Acid Sequence↗
PubMed1988

[Role of the electrophysiologic examination in the diagnosis of Bassen-Kornzweig syndrome].

An autosomal recessive disorder, abetalipoproteinemia or Bassen-Kornzweig disease, concerning two sisters are described. This disorder, clinically similar to Friedreich ataxia, should be examined by electrophysiological and laboratory procedures because of the possibility of treatment by high doses of vitamin A and E. The routine electrophysiological examination of the two sisters revealed a degenerative spinocerebellar and peripheral nervous process which confirmed the damage of large myelinated fibers, as reported in the literature: neurogenic muscular atrophy of distal muscles, polyphasic motor unit potentials, moderately decrease of lower motor and sensory nerve conduction rates, and reduced amplitude of evoked responses in sensory nerves and muscles. We stress out the diagnostic value of the heterogenous conduction decrease in the distal motor fibers, signs of processes of demyelination or distal regeneration.

Abetalipoproteinemia↗
PubMed1988

Local intravascular effects of the nitinol wire blood clot filter.

To determine the biocompatibility and thrombogenicity of nitinol blood clot filters, we inserted 27 nitinol wire devices into the venae cavae of 16 dogs and one sheep and studied the results angiographically and at autopsy after periods of one week to four years. Filter shape, location in the vena cava, wire cleaning procedure and wire surface finish were varied. All 18 cleaned nitinol wire filters remained patent by venogram, although some showed small venographic filling defects caused by adherent organized thrombi. Filters in larger veins tended to have less thrombus. Surface polishing and filter shape had no observable effect on thrombogenicity. Histologic study revealed patchy chronic inflammation at the surface of uncleaned filters but only benign fibrous tissue reaction for the cleaned filters. Neointimal tissue overgrowth was observed where nitinol wire contacted the wall of the vena cava. Two filters implanted for four years had no appreciable weight loss caused by corrosion. Platelet adhesion and plasma coagulation effects of nitinol wire were tested in vitro in human blood and found to be similar to those of stainless steel, which is used in comparable devices. These encouraging results suggest that nitinol may be a promising material for human intravascular prosthetic applications.

Alloys↗