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Biomedical subjects

M Samson

Publications and source records attributed to M Samson.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Quality of life and functional indices in osteoarthritis].

The main Indices of Quality of Life used in rheumatology and their aims and applications are surveyed. Their use in osteoarthritis implies a few issues that are addressed in a critical manner. Indices of Quality of Life are useful to measure deficiency resulting from osteoarthritis by comparison with other rheumatic diseases, as rheumatoid arthritis, connective tissue diseases, fibromyalgia... They are sensitive enough for apraising the domains improved by a radical treatment such as joint replacement. However, their scores are only slightly changing in most of the drug trials, in which the more simple functional indices seem demonstrative enough. Last but no least, they are notably time consuming for both the patient and the physician.

Activities of Daily Living↗
PubMed1993

[Unusual secondary coxarthrosis and posterior coxarthrosis].

Certain atypical forms of osteoarthritis of the hip are misleading: forms with very severe pain, forms with pain predominantly in the sitting position, forms with disproportionate pain. These atypical features can sometimes be explained by certain anatomical arrangements: superomedial narrowing over an aggressive double line, posterior osteoarthritis of the hip which can only be demonstrated on a false lateral view in the form of posteroinferior narrowing with its corollaries: anterosuperior diastasis and marked osteophytes of the posterior horn appearing to advanced underneath the femoral head on the lateral view. These atypical forms frequently only last several months or years. Posterior osteoarthritis of the hip has a less severe and slower course than the usual forms with superior narrowing.

Adolescent↗
PubMed1992

Triiodothyronine binding sites in the rat erythrocyte membrane: involvement in triiodothyronine transport and relation to the tryptophan transport System T.

The binding of L-triiodothyronine (T3) to rat erythrocyte membranes (ghosts and peripheral protein-depleted vesicles) was studied under equilibrium conditions. Ghosts contained high-affinity T3 binding sites whose dissociation constant (21 nM) was similar to the equilibrium-exchange Michaelis constant of T3 transport measured in ghosts. Each ghost contained about 8.10(3) high-affinity binding sites. The high-affinity T3 binding was stereospecific and was inhibited by L-tryptophan (Trp) but not by L-leucine. The iodothyronine and amino acid specificity of binding is therefore similar to that of System T, the erythrocyte T3/Trp transporter. These Trp-inhibitable high-affinity T3-binding sites were also present in peripheral protein-depleted membrane vesicles, indicating that they are integral part of the membrane. Ghosts prepared from human erythrocytes, which have very low System T transport activities, contained no detectable Trp-inhibitable high-affinity T3-binding sites. In rat erythrocyte ghosts, N-ethylmaleimide inactivated both the binding and the transport of T3. This inactivation was blocked by T3 and Trp with similar efficiencies. Phenylglyoxal, an arginine residue modifier, also inhibited both high-affinity T3 binding and System T transport activity. It is concluded that the Trp-inhibitable high-affinity T3-binding sites in the rat erythrocyte membrane are likely to be associated with System T.

Animals↗
PubMed1992

Thyroid hormone concentrative uptake in rat erythrocytes. Involvement of the tryptophan transport system T in countertransport of tri-iodothyronine and aromatic amino acids.

The kinetic properties of transport system T, which is specific for uptake of aromatic amino acids, were studied in rat erythrocytes in the presence of leucine in order to block the neutral amino acid transport system L. Since the triiodothyronine (T3) transport system and system T are closely related, the trans effect of T3 and tryptophan on [3H]tryptophan transport and the trans effects of aromatic amino acids on [125I]T3 transport were studied. Equilibrium-exchange, zero-trans and infinite-trans studies of [3H]tryptophan transport indicated that system T in rat erythrocytes is a simple carrier with exchanging properties resulting in trans-acceleration of influx and trans-inhibition of efflux when tryptophan was present at the trans side of the membrane. In erythrocytes preloaded with unlabelled tryptophan, countertransport resulted in a 7-fold accumulation of labelled substrate inside the cells. T3 on the trans side of the membrane inhibited both influx and efflux of tryptophan, with Ki values similar to the Km values of the T3 transport system. Extracellular tryptophan trans-inhibited [125I]T3 efflux in a manner similar to [3H]tryptophan efflux. Preloading erythrocytes with tryptophan resulted in trans-acceleration of T3 uptake and a transient 5-fold accumulation of free T3 into erythrocytes. Phenylalanine and tyrosine (but not the D-isomer of tryptophan or non-aromatic amino acids) also produced trans-acceleration for T3 uptake and T3 countertransport. These results are compatible with a kinetic model assuming a common simple carrier of T3 and tryptophan transport and point to a countertransport pathway driving the uphill uptake of T3 by hetero-exchange with intracellular aromatic amino acids.

Animals↗
PubMed1992

[The value of a clinical test for the evaluation of bladder-sphincter function in the management of urinary disorders of the elderly].

The authors report the value of a clinical test for the evaluation of vesico-sphincteric function in the demonstration of urinary disorders in the elderly. This simple, inexpensive test which can be performed at the patient's bedside, was performed in 175 elderly patients with a mean age of 81.2 years, mostly suffering from urinary incontinence (66.2%) and mostly (80%) derived from intermediate and long-term geriatric units. The mechanisms most often detected was detrusor instability (41% of patients). Cystomanometric data, obtained in 80 patients, were analysed and compared retrospectively with the data of the test: they demonstrated a good correlation in terms of evaluation of detrusor stability. As part of the overall management, this test constitutes a real diagnostic tool available to nursing staff, particularly in geriatric institutions not equipped with more specialised investigations.

Aged↗
PubMed1991

[Tendinitis of the hip region].

Tendinitis and bursitis are less common around the hip than around the shoulder. Nevertheless, they must be recognized to avoid unnecessary and costly diagnostic errors. Their various clinical forms are studied in detail. Tendino-bursitis of the gluteus medius muscle is the most frequent in its subacute form, but it is rare in its acute, pseudo-gouty form. Calcification of the reflected tendon of the rectus femoris muscle often closely resembles arthritis of the hip. Synovial cysts of the psoas bursa and rupture of the gluteus medius tendon are rare but must be known. Local injections of corticosteroids play an important part in the treatment of these diseases.

Hip Joint↗
PubMed1991

Acute complications of percutaneous transluminal coronary angioplasty for total occlusion.

The incidence of major complications after percutaneous coronary angioplasty (PTCA) of a totally occluded artery was assessed retrospectively. A total of 1649 PTCA procedures were analyzed. After exclusion of procedures for acute myocardial infarction or total occlusion that resulted from restenosis, 90 patients were selected. Forty-four patients (49%) had stable angina and 46 (51%) had unstable angina. The estimated duration of occlusion was 87 +/- 78 days in patients with stable angina, as compared with 10 +/- 8 days in patients with unstable angina (p less than 0.001). Abrupt vessel closure during PTCA occurred only in patients with unstable angina (0% versus 17%, p less than 0.05). The major complication rate was 2.5% in the stable angina group, and 20% in unstable angina group (p less than 0.01). This rate was also significantly higher than the complication rate of 8% observed in 442 procedures that were performed during the same period in patients with the unstable angina and nonocclusive stenosis (p less than 0.01). Patients with unstable angina who undergo PTCA of a totally occluded artery represent a subset of high risk for major complications.

Acute Disease↗
PubMed1991

Long-term follow-up after attempted angioplasty of saphenous vein grafts: the Thoraxcenter experience 1981-1988.

Between 1981 and 1988, 107 percutaneous transluminal coronary angioplasty (PTCA) procedures, including repeat PTCA, were performed in 84 patients with previous coronary artery bypass grafting (CABG). Fifty-nine patients underwent a first angioplasty of the vein graft alone, and 25 underwent a first PTCA of the graft and one or more native vessels. Seventeen patients underwent two procedures, four patients three procedures and one patient four procedures. In 84 first angioplasties, 133 lesions were attempted; 40 lesions in native vessels and 93 graft lesions (28 ostial stenoses, 33 shaft stenoses, and 32 stenoses at the distal anastomosis). Three patients died during their hospital stay. Two patients underwent emergency CABG. Seven patients sustained an acute myocardial infarction (AMI), among whom five underwent a PTCA of an occluded vessel. The clinical primary success rate per patient was 82%. After five years, 70% of patients were alive. At a median follow-up of 2.1 years, 41% of patients were alive and event-free (no AMI, no repeat CABG, no repeat PTCA). Symptomatic improvement was maintained in 36% of patients. Angioplasty of grafts may be an alternative to re-operation in selected patients with previous bypass surgery.

Adult↗
PubMed1991

[Value of a clinical test for the assessment of bladder and sphincter function in the management of urinary disorders in the aged].

The authors report about the merits of a clinical test for the evaluation of bladder and sphincter function in the analysis of urinary disorders in the aged. This simple and inexpensive bedside test has been carried out in 175 subjects whose mean age was 81.2 years, and the majority of whom (66.2%) presented with urinary incontinence; 80% of the patients came from longterm-care geriatric departments. The most frequent mechanism is bladder instability (41% of all patients). The cystomanometric data obtained in 80 subjects were analysed and retrospectively compared to the test data: they showed good correlation for the study of vesical stability. From the viewpoint of general health care, this test is a real diagnostic tool for the practitioners, in particular in geriatric departments without further specialised exploration commodities.

Age Factors↗
PubMed1991

Indices of severity in osteoarthritis for weight bearing joints.

Indices of severity for hip and knee diseases may be applied to any disabling disease of these joints, but were especially designed and validated for osteoarthritis (OA). With experience, a score could be obtained in 3-4 minutes and the reproducibility was satisfactory. Their discriminant power in a double blind crossover trial of a given nonsteroidal antiinflammatory drug versus placebo was, among other assessment tests, in the first rank concerning the hip OA index, in the 4th rank concerning the knee OA index. These indices allow longterm followup of OA, rationalization of decision for prosthesis, when the score reaches 8 to 12 points despite correct medical treatment.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

[Pain-function indices for the follow-up of osteoarthritis of the hip and the knee].

Algo-functional or severity index for hip diseases (AFIH), proposed in 1980 and validated in 1981, and algo-functional or severity index for knee diseases (AFIK), validated in 1985-1987, were applied to osteo-arthritis of the hip and of the knee. With strictly standardized interviews and well-trained investigators (20 to 30 patients), these indices are reliable: the interobserver reproducibility is good (mean discrepancy: 1/2 point) and the score usually decreases 3 points (mean) under active drug treatment. Each index was individually validated. The severity index for hip is more discriminant than that for knee diseases. The place of each index among the other assessment tests was appraised according to their discriminant capacity. These indices are useful: 1) for drug trials (analgesics and NSAIDs); 2) for the long term follow-up and the so-called chondroprotective agents trials; 3) for a rational decision concerning hip or knee prosthesis (score reaching 8 to 12 points). These AFIH and AFIK are well suited to daily practice and are not time-consuming: 3 to 4 minutes for each.

Cross-Sectional Studies↗
PubMed1990

Evidence for a close link between the thyroid hormone transport system and the aromatic amino acid transport system T in erythrocytes.

The transport of [125I]triiodothyronine ([125I]T3) and [3H]tryptophan ([3H]Trp) by washed rat erythrocytes was studied at 25 degrees C in the presence of leucine in order to block the neutral amino acid transport system L. Eadie-Hofstee plots of initial velocity data gave the following values of Km (micromolar) and Vmax (nanomole/min/10(8) cells): 0.122 +/- 0.007 and 0.140 +/- 0.021 for T3, and 558 +/- 28 and 17.4 +/- 2.3 for Trp (n = 5). The Trp transport system in rat erythrocytes is similar to the human erythrocyte aromatic amino acid-specific system T described by Rosenberg et al. (Rosenberg, R., Young, J. D., and Ellory, J. C. (1980) Biochim. Biophys. Acta 598, 375-384). Unlabeled aromatic amino acids (e.g. Trp, phenylalanine, tyrosine) competitively inhibited [125I]T3 uptake and unlabeled iodothyronine analogues (e.g. T3, D-T3, thyroxine, thyronine) competitively inhibited [3H]Trp uptake. The inhibition constants of these competitors measured with each labeled substrate were highly correlated. N-Ethylmaleimide irreversibly inhibited T3 and Trp transport and each substrate protected the transport system of the other from inactivation by N-ethylmaleimide. The Vmax of T3 and Trp transport by human erythrocytes were 500 and 120 times lower, respectively, than those of rat erythrocytes (0.30 and 126 pmol/min/10(8) cells, respectively). The T3 and Trp transport activities of sheep erythrocytes were undetectable. These results indicate that T3 and Trp either share a common multi-specific transport system or are transported by closely linked systems which interact in the erythrocyte membrane.

Animals↗
PubMed1990

Transducer manometry and the effect of body position on anal canal pressures.

Anal canal manometry is performed conventionally with balloons, sleeves, perfused or nonperfused open-tipped catheters, or with multiport probes. The authors constructed a new manometer with four transducers embedded in a probe (15 mm outside diameter) and oriented radially, 90 degrees apart. The transducer probe was validated in 27 healthy volunteers by comparing its performance to that of a standard four-port perfused manometer and then used to measure anal canal and rectal pressures in body positions more physiologic (standing, sitting) than that usually employed (left lateral) for such measurements. Both devices measured similar anal canal resting pressure in the left lateral position (mid canal, 58 +/- 3 mm Hg perfused vs. 62 +/- 4 mm Hg transducer; P greater than 0.05). The transducer probe, however, recorded higher squeeze pressures (mid canal, 100 +/- 6 mm Hg perfused vs. 143 +/- 14 mm Hg transducer; P less than 0.05). The transducer probe detected higher intrarectal and resting anal canal pressures when subjects were standing or sitting, compared with the left lateral position (rectum, 3 +/- 1 mm Hg left lateral; 17 +/- 2 mm Hg standing; 20 +/- 1 mm Hg sitting; P less than 0.05; mid anal canal, 57 +/- 3 mm Hg left lateral; 86 +/- 4 mm Hg standing; 81 +/- 5 mm Hg sitting, P less than 0.05). The rise in resting anal canal pressure was uniform circumferentially. Neither anal canal length nor squeeze pressure changed with change in position. The authors concluded that 1) transducer manometry recorded similar resting but higher squeeze pressures compared with perfused manometry; 2) transducer manometry recorded the same radial variation in anal canal resting and squeeze pressures as that recorded by the perfused manometer; and 3) standing and sitting caused a four-fold rise in intrarectal pressure, which was associated with a concomitant rise in resting anal canal pressure.

Adult↗
PubMed1990

Successful multiple segment coronary angioplasty: effect of completeness of revascularization in single-vessel multilesions and multivessels.

A long-term follow-up study was performed to evaluate the long-term value of performing multiple dilatations according to their procedural (single-vessel multilesion or mutltivessel dilatations) and anatomic types (single-vessel disease with multiple dilatations or multivessel disease dilatations with complete and incomplete revascularization). From 1980 until 1988, 248 patients met the following criteria: (1) at least two lesions dilated (range: 2 to 4) and (2) all attempted lesions successfully dilated. The mean length of follow-up was 33 months. The end points analyzed were death, myocardial infarction, redilatation, and bypass surgery. No differences were found for these events between the single-vessel multilesion group (144 patients) and the multivessel group (104 patients). The 4.5-year probability of event-free survival was 68% and 70%, respectively, for the multilesion group and the multivessel group. In the event-free patients, 57% versus 59% were asymptomatic and 45% versus 46% were not taking antianginal drugs. In the anatomic subgroups, there were less event-free patients in the cohort of incompletely revascularized multivessel disease patients (55% of 55 patients) when compared with the cohort of those who were completely revascularized (84% of 79 patients) or when compared with the single-vessel disease multiple dilatation patients (74% of 107 patients). The 4.5-year event-free survival probability for each group was 44%, 78%, and 74%, respectively. This difference was caused by more infarctions (9% versus 2% versus 4%, respectively) and bypass operations in the multivessel disease, incomplete revascularization group (20% versus 5% versus 10%, respectively). In event-free patients, improvement of angina was similar and was documented in over 85% of patients in each group. Furthermore, the number of asymptomatic patients at follow-up was similar in all groups except that within the incomplete revascularization group, less patients were free of antianginal drugs (21% versus 51% versus 48%). Finally, 48% of the entire cohort performed an exercise test 4.6 months (mean) after dilatation and no difference was found in any of the variables in any group. About 10% of the patients experienced angina and approximately 30% had a positive exercise test for ischemia by ST segment criteria. The functional performance in every group was over 90% of the predicted work load. These results suggest that completeness of revascularization in multivessel disease patients is an important prognostic variable. However, the symptomatic improvement after dilatation is very rewarding in all subsets of patients and argues in favor of the continued use of multiple dilatations as a treatment strategy.

Aged↗
PubMed1990

Transport of thyroid hormones by human erythrocytes: kinetic characterization in adults and newborns.

The uptake of [125I]T3 and [125I]T4 by human erythrocytes was studied. The erythrocytes were obtained from adult subjects (28-41 yr old) and suspended in a protein-free medium. The half-times of equilibration for both T3 and T4 were 6 min. At equilibrium, T3 was concentrated 55-fold inside the cells, while T4 was concentrated 40 times, but these accumulations were not dependent on either cellular ATP or the transmembrane Na+ gradient. The amounts of cell-associated thyroid hormones were 20 times (T3) and 17 times (T4) higher than the amounts of free extracellular hormones at 5 X 10(9) erythrocytes/mL (the blood concentration). Oligomycin and phloretin inhibited T3-saturable transport (but not T4 transport) independently of cellular energy. We suggest that thyroid hormones are concentrated by intracellular trapping. The rates of T3 and T4 efflux from preloaded erythrocytes were similar to the influx rates. The initial velocities of T3 (but not T4) uptake and efflux were 70% saturable. The uptake was specific because the unlabeled analogs T4, triiodothyroacetic acid, rT3, D-T3, and D,L-thyronine inhibited [125I]T3 uptake 60, 125, 160, 190, and 1600 times less, respectively, than did unlabeled T3. The kinetic parameters of T3-saturable uptake, Km, and maximum velocity were determined for three groups of subjects: newborns, 28 to 41-yr-old adults, and 76 to 90-yr-old adults. The Km (67 nmol/L in 28 to 41-yr-old adults) was not age dependent, BUT the maximum velocity was significantly higher in newborns than in adults. We conclude that T3 transport across the human erythrocyte membrane is mediated mainly by facilitated diffusion, whereas T4 transport results from free diffusion. Human erythrocytes might act as a circulating pool of thyroid hormones, especially T3 in newborns.

Adenosine Triphosphate↗