Biomedical subjects

F Michel

Publications and source records attributed to F Michel.

At least 181 records · Page 10Linked to original sources

PubMed1990

[Treatment of urethral stenosis using a pedicled flap of the scrotal skin. Long-term results in 16 patients].

The scrotal skin is vascularized in part by means of the superficial perineal branch of the internal pudendal artery. This nutrient pedicle, together with the scrotal skin dependent on it, can be isolated. The urethra is approached via the perineum. The stricture is incised longitudinally right down to the healthy area. The scrotal flap and pedicle are mobilized, and then anastomosed along the edges of the urethra. From March 1983 through April 1987, sixteen patients have been operated. Postoperative results: the mean follow-up for the 16 patients is 60 months with extremes of 24 and 66 months. 13/16 patients show good results (81%). 3/16 patients show poor results with recurrence of the stricture localized at the junction of the flap and healthy urethra. Such recurrences have yielded to treatment, in two cases, by optical urethrotomy and, in the other case, by means of a new scrotal flap.

Follow-Up Studies↗

PubMed1990

[Low-pressure enterocystoplasty after prostato-cystectomy for cancer. Apropos of 13 cases].

Thirteen patients were operated for bladder carcinoma, from November 1987 to September 1988, using a Camey type II low pressure ileal bladder replacement. Clinical, radiological and urodynamic findings were studied. Diurnal continence was always acquired at three months. In terms of nocturnal continence, only 75 percent of the patients are comfortable, while two patients require oxybutinin to remain continent. Urodynamic exploration showed a low pressure in 8 patients, but a high pressure peak in 4 patients. Radiological study showed integrity of the urinary tract. This work confirmed the improvement obtained with the Camey II procedure. Nevertheless, it also shows the failure of the method with occasional high pressure peaks. We think that a more anatomical bladder reconstruction, such as Hautmann Pouch, may improve the results for nocturnal continence. This needs to be confirmed by a comparative study.

Aged↗

PubMed1990

[Importance of masseter insertion surface in different mammal groups].

The objective of this study is to compare the strength of the masseter muscle in various mammals by calculating the ratio between insertion area of the masseter and total mandibular surface. We will also determine the factors capable of modifying the insertion area of this masticatory muscle.

Anatomy, Comparative↗

PubMed1989

The guanosine binding site of the Tetrahymena ribozyme.

The self-splicing Group I introns have a highly specific binding site for the substrate guanosine. Mutant versions of the Tetrahymena ribozyme have been used in combination with guanosine analogues to identify the nucleotide in the ribozyme that is primarily responsible for recognition of the guanine base.

Animals↗

PubMed1989

Comparative and functional anatomy of group II catalytic introns--a review.

The 70 published sequences of group II introns from fungal and plant mitochondria and plant chloroplasts are analyzed for conservation of primary sequence, secondary structure and three-dimensional base pairings. Emphasis is put on structural elements with known or suspected functional significance with respect to self-splicing: the exon-binding and intron-binding sites, the bulging A residue involved in lariat formation, structural domain V and two isolated base pairs, one of them involving the last intron nucleotide and the other one, the first nt of the 3' exon. Separate sections are devoted to the 29 group II-like introns from Euglena chloroplasts and to the possible relationship of catalytic group II introns to nuclear premessenger introns. Alignments of all available sequences of group II introns are provided in the APPENDIX.

Animals↗

PubMed1989

Isolation and characterization of the rainbow trout erythrocyte band-3 protein.

Rainbow trout (Salmo gairdneri) band-3 protein was isolated from trout erythrocyte plasma membranes by a combination of preparative SDS/PAGE and electroelution. High purity and recovery of the plasma membranes were achieved by a new method. This was demonstrated using 4,4'diiso-thiocyano[3H2]dihydro-stilbene 2,2'disulfonic acid (3H2DIDS) which specifically labels band-3 protein. On SDS/PAGE, band-3 protein yields a similarly diffuse pattern, as does mammalian band-3 protein, with an apparent Mr of 116,000. In situ chymotryptic cleavage/cross-linking experiments with 3H2DIDS reveal that the fragments cross-link as in human and mouse band-3 proteins but that there are minor differences. Treatment of trout erythrocytes with trypsin results in cleavage of the band-3 protein. Purified polyclonal antibodies raised against trout band-3 protein react with trout band-3 protein and do not crossreact with mouse or human band-3 protein. They react specifically with only one chymotryptic fragment of trout band-3 protein.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1989

[Accidental discovery of renal cancer by ultrasonography].

A retrospective study of 152 consecutive patients admitted for renal carcinoma between January, 1969 and August, 1987 showed that these patients could be divided into two groups, the dividing line being 1980, date of the advent of ultrasonography. Compared with the 68 patients treated between 1969 and 1980, the 84 patients treated between 1981 and 1987 had a significantly greater number of asymptomatic renal carcinomas. The asymptomatic tumours discovered incidentally by ultrasounds were less advanced than the symptomatic tumours, the difference between the 2 groups being highly significant. The diagnosis of asymptomatic renal carcinoma at an early stage suggests that these tumours might have a better prognosis. These data underline the usefulness of a systematic study of the kidney during all abdominal or vesicoprostatic ultrasonographic explorations.

Female↗

PubMed1989

Unusually high frequencies of HIV-specific cytotoxic T lymphocytes in humans.

CTL specific for the HIV belong to the CD8 subset of T lymphocytes, and their activity is restricted by class I HLA transplantation Ag. In this report, HIV-specific CTL and their precursor cells were quantified by limiting dilution analysis. CTL were recovered from the lungs, lymph nodes, and blood of asymptomatic seropositive carriers and of patients with AIDS. HIV was found to be very immunogenic. High frequencies of both HIV-specific CTL and CTL precursor cells were detected in infected individuals. These CTL killed autologous HIV-infected macrophages and T4 lymphoblasts. They also killed doubly transfected P815-A2-env-LAV mouse tumor cells, which express the human HLA-A2 gene and the HIV-1 env gene. In the longitudinal studies of two HIV-infected patients, CTL and CTL precursor cell frequencies decreased as the clinical and immunologic status of the patients deteriorated. Most surprisingly, PBL from seronegative donors also responded to HIV stimulation in vitro and generated large numbers of HLA-restricted, HIV-specific CTL.

Animals↗

PubMed1989

Multiple subsets of HIV-specific cytotoxic T lymphocytes in humans and in mice.

The human immunodeficiency virus type 1 (HIV-1) induces a strong cytotoxic T lymphocyte (CTL) response in humans following infection. HIV-specific CTL can be detected directly in the blood and lungs of infected patients, and can be expanded in vitro by stimulation with autologous HIV-infected lymphoblasts. Furthermore, CTL specific for HIV envelope glycoprotein gp160 have been obtained in mice by immunization with recombinant vaccinia virus (VV) that carry the HIV env gene. In this study, we show that mice also produce strong CTL responses to gag and nef proteins following immunization with VV recombinants, thus providing a convenient model system to study T lymphocyte immunity to defined HIV antigens. To determine the specificity of circulating HIV-immune CTL in humans, a panel of doubly transfected mouse P815 tumor cells was produced which express the human HLA-A2 or HLA-A3 transplantation antigen gene and one HIV-1 gene (env, gag or nef). Using these cells as targets to CTL, we show that HIV-infected humans carry co-existing CTL sub-populations of different specificities. Each subpopulation appears to vary in intensity among different individuals. Surprisingly, CTL specific for regulatory, non-structural nef protein appear to be a major constituent of the human immune response to HIV.

Animals↗

PubMed1989

DNA sequence analysis of the 24.5 kilobase pair cytochrome oxidase subunit I mitochondrial gene from Podospora anserina: a gene with sixteen introns.

The DNA sequence of a 26.7 Kilobase pair (10(3) base pairs = 1 Kb) region of the mitochondrial genomes of races s and A from Podospora anserina was determined. Within this region, the 24.5 Kb cytochrome oxidase subunit I gene was located and its exon sequences determined by computer analysis comparisons with other fungal genes. The Podospora COI gene was interrupted by two group II introns (one in race s) and fourteen group I introns ranging in size from about 2.2 Kb to 404 bp. Earlier studies on secondary structure analysis, as well as comparison of their open reading frames (ORFs), showed that the two group II introns were closely related. The fourteen group I introns were representatives of three subgroupings (IB, C and a new category, subgroup ID). Two of these group I introns were separated by just a single exon codon. The analysis of all these introns is discussed in comparison with other fungal introns as well as with the known Podospora anserina introns.

Amino Acid Sequence↗

PubMed1989

DNA sequence analysis of the apocytochrome b gene of Podospora anserina: a new family of intronic open reading frame.

The 5,969 bp (base pair) DNA sequence of the apocytochrome b mitochondrial (mt) gene of race A Podospora anserina was located in a 8.5 Kbp region. This gene contained a 2,499 bp subgroup IB and a 1,306 bp subgroup ID intron as well as a 990 bp subgroup IB intron which is present in race A but not race s. The large subgroup IB intron and the race A specific IB intron both contained potential alternate splice sites which brought their open reading frames into phase with their upstream exon sequences. All three introns were compared with regard to their secondary structures and open reading frames to the other 30 group I introns in Podospora anserina, as well as to other fungal introns. We detected a new family of intronic ORFs comprising seven P. anserina introns, several N. crassa introns, as well as the T4td bacteriophage intron. Sequence similarities to intron-encoded endonucleases were noteworthy. The DNA sequences reported here and in the accompanying paper complete the analysis of race s and race A mitochondrial DNA.

Amino Acid Sequence↗

PubMed1989

Lexicalization in an anomic patient.

Following a haemorrhage in the left temporal lobe, a 25 yr-old left-handed male patient presented a word finding difficulty, particularly in confrontation naming. The patient had extensive semantic knowledge of the items that he was not able to name. Several experiments showed that he had a poor phonological image of the target word and was poorly helped by phonological cues. He had a better knowledge of the graphological image, but it remained insufficient to result in word retrieval. On several occasions, when the patient failed to name a picture which happened to be lexicalized by a polysemous word, a residual covert word form could still operate as a link between different meanings of the target word; then, the patient produces a word or a circumlocution related to one meaning which was not the illustrated meaning. This kind of response could be called a parasemia. We postulate that the patient's deficit took place outside semantic treatment and before achievement of lexical (phonological or graphological) output.

Adult↗

PubMed1989

Comparative analysis of actual and mental movement times in two graphic tasks.

This study compared the temporal organization of graphic movements executed either actually or mentally. Six subjects had to perform two tasks, writing a sentence and drawing a cube, either as a real performance or as an imagined one, with either the right or the left hand, and with either a small or a large tracing amplitude. In the same subject, for the same hand, mental and actual movement times were both very stable and very close from trial to trial regardless of the tracing amplitude. Thus, mental movements mimic closely real movements in their temporal organization and are likely to involve the same planning program.

Adult↗

PubMed1989

Mechanism of the activation of arachidonic acid release by oxysterols in NRK 49F cells: role of calcium.

We previously demonstrated that oxysterols added to the culture medium of NRK 49F cells labelled with [14C] arachidonic acid potentiated arachidonic acid (AA) release and prostaglandin (PG) E2 biosynthesis induced by the activation of these cells with fetal calf serum (FCS). In the absence of FCS, oxysterols had no effect on AA release. As phospholipase (Plase) A2 activity is Ca2(+)-dependent, we investigated whether oxysterol potentiating effect on AA release was related to an effect of these compounds on cell Ca2+ concentration. In this paper, we show that the intensity of potentiation by oxysterol varies with the external cell Ca2+ concentration; when external Ca2+ is chelated by EGTA, the oxysterol effect persists, though it is decreased. The Ca2+ channel inhibitor nifedipine does not decrease the potentiating effect of 25-OH cholesterol, indicating that, if oxysterol favours Ca2+ entry into the cell, the nifedipine inhibited channel is not involved. At the usual concentration (5 micrograms/ml), oxysterols are not able to increase, immediately or after a short time of contact (90 min) the concentration of intracellular free Ca2+ ([Ca2+])i measured by fluorescence of Quin-2; at very high concentration of oxysterol (25 micrograms/ml), [Ca2+]i only slightly increases (+30%). The liberation of AA induced by cell activation with the Ca2+ ionophore ionomycin is also potentiated by 25-OH cholesterol. All these observations are not in favour of a proper effect of oxysterols on cell Ca2+ level.

Animals↗

PubMed1989

Arachidonic acid release and prostaglandin biosynthesis in synchronized rat embryo fibroblasts.

Arachidonic acid (AA) release and prostaglandin (PG) biosynthesis were studied in rat embryo fibroblasts (R 129) synchronized by double thymidine-excess block. Whatever the culture medium was (medium 199 supplemented with 10% fetal calf serum (FCS) or 1% FCS plus 0.1% bovine serum albumin (BSA], AA release rapidly increased until the 4th hour of the cell cycle (S phase), remained on a plateau in G2M and G1 phases and did not increase again in the S phase of the following cell cycle. Time course and amplitude of AA release in synchronized cells did not differ from what it was observed after the simple renewal of the culture medium in asynchronous cells. So AA release seemed to be independent of the cell cycle. By contrast, PGE2 and PGF2 alpha biosynthesis clearly increased in the S phase of two consecutive cell cycles, indicating that cyclooxygenase activity and not phospholipase A2 activity vary according to the cell cycle.

Animals↗

PubMed1989

Substance P activation of bronchoalveolar macrophages from asthmatic patients and normal subjects.

The role of substance P in the pathogenesis of asthma is unclear. Animal studies suggest that it may be important, whereas human studies do not confirm this. Alveolar macrophages can be recovered easily by bronchoalveolar lavage (BAL) and stimulated in vitro. To assess the role of substance P in humans, we tested its ability to stimulate alveolar macrophages from six normal subjects and seven asthmatic patients. BAL cells were separated by adherence and alveolar macrophages constituted 95% of the adherent cell population. Four concentrations of substance P were used (10(-7), 10(-6), 10(-5), 10(-4) M). To assess the non-specific activation of alveolar macrophages we used three concentrations of lipopolysaccharides (LPS) (5, 10, 20 micrograms/ml). The stimulation of alveolar macrophages was assessed by the release of thromboxane B2 by radioimmunoassay. This study indicates that alveolar macrophages are stimulated by LPS but are poorly activated or not at all by substance P.

Adolescent↗

PubMed1989

[Ambulatory long-term oxygen therapy].

Administration of oxygen is an accepted component of the treatment of acute diseases leading to temporary arterial hypoxemia. In addition, long-term oxygen therapy of patients with chronic hypoxemia secondary to chronic obstructive lung disease (COPD) has become increasingly common, after beneficial effects on quality of life and survival have been reported. This form of treatment, however, is costly, rather complex and demanding. Therefore, strict criteria have to be considered in the selection of hypoxemic patients with COPD. This article reviews the tests and criteria required for the prescription of long-term oxygen therapy as well as newer technical aspects in its application with special emphasis on transtracheal catheters.

Ambulatory Care↗

PubMed1989

[Are the lesions responsible for prosopagnosia always bilateral?].

To localize the lesions responsible for prosopagnosia one must first consider how recent anatomico-physiological data have modified our view of the visual system: the visual cortex has been parceled into a mosaic of visual areas, each of them processing preferentially a particular feature (form, colour, movement); there is evidence of a face area in the monkey temporal lobe, and a new model of the inferior longitudinal fasciculus has been offered. It is currently accepted that face recognition deficits are due to bilateral occipito-temporal lesions, but in view of several recent reports in which the lesions were localized on CT or MRI one may doubt that these lesions are necessarily bilateral. In some cases a right unilateral lesion seemed to be sufficient to induce prosopagnosia.

Agnosia↗