Biomedical subjects
Publications and source records attributed to C Michel.
The authors report the use of endovascular stents in the treatment of one Cockett's syndrome. The compression above left iliac vein ranged on 5 cm. The number of stents placed in the patient was as follow: two stents. An ipsilateral femoral approach was used. The stents were placed immediately after dilatation.
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Great versatility gives composed scapular flaps a particular significance for the reconstruction of defects in face and skull: According to individual requirements one up to five separate elements may be transferred with one vascular pedicle. Anatomical studies of 120 scapulas measured a mean length of 13.4 cm and a mean diameter of 1.2 cm of the lateral margin offering sufficient bone for most indications in the visceral skull. Up to three cutaneous flaps may cover nearly every defect in the head. 44 patients were treated in the years 1989 to 1993 using scapular flaps, most of them combinations consisting of bone and skin elements. In two patients a so called 4-in-1-flap was transferred including the latissimus-dorsi-flap. All donor sites could be closed primarily. Venous thrombosis caused one loss of a flap. Infections healed without sequelae. Medical gymnastics brought full rehabilitation of the donor site within 6 months.
From 1981-1992 we reconstructed the temporomandibular joint in 42 patients. In 33 cases reconstruction followed tumour resection of the mandible, almost advanced squamous cell carcinomas of the retromolar region. Primary reconstruction was made by an alloplastic condylar prosthesis combined with a plate for mandibular reconstruction. 2 years after first treatment secondary reconstruction followed by transplantation of a free iliac bone graft. In some cases a new condylus was formed using autogenous rib graft or allogenous cartilage. Result was adequate and painless oral aperture. For reconstruction after ankylosis, arthrosis or arthritis we use a autogenous costochondral graft. 9 patients received such treatment. In 5 or 9 cases with severe ankylosis we prefer a two-time-approach: after resection of the ankylosis we first fix an alloplastic implant (Palacos) at the skull base for distraction of the scar. Two or three years later we do secondary reconstruction with a costochondral graft. The final result strongly depends on functional postoperative treatment and the compliance of the patient.
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The problem of chronology between different surgical acts is at stake when a patient suffering from carotid and aorto-iliac or femoropopliteal diseases requires surgery. The joint operation increases surgical risk and its practice penalizes the surgeon. Sequential surgery is safer. It does not increase the risk of a adverse evolution of the diseases areas which has not been operated on at time of the first operation.
Glucose metabolism has been studied in the auditory cortex of human subjects with deafness of early onset, and compared to normal subjects with ears plugged. The metabolism in the auditory cortex and in the association auditory cortex was higher in deaf subjects than in normal subjects. This result is compared to similar observations that we made previously in the visual cortex of human subjects with blindness of early onset.
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Resuscitation outside the hospital setting is a topic of increasing interest and discussion. A satisfactory neurologic outcome after acute cardiac arrest depends on immediate basic and the advanced cardiac life support (BCLS + ACLS). To achieve better results in Switzerland it is necessary to promote resuscitation performed by the layman (BCLS) and improve the content and structure of emergency calls and prehospital first aid. Since a satisfactory neurologic outcome depends on an immediate start to basic resuscitation, general information and teaching to the public must be promoted. To secure rapid assistance there should be one single phone number (e.g. 144) for emergency calls throughout Switzerland. Professionalism in the workup of emergency calls and in first aid by specialized personnel produces good results not only in cardiac but also in trauma patients.
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Lectin binding in normal and irradiated embryonic mouse tissues on day 10 of gestation was studied by peroxidase techniques. Specific binding of Dolichos biflorus lectin (DBA) was detected in the mesodermal blood vessels and in the otic vesicles. The amount of DBA as well as that of soybean agglutinin (SBA) and peanut agglutinin (PNA) increased after exposure to low doses of radiation (0.25, 0.50 and 0.75 Gy). The modifying influence of ionizing radiation was observed in the pituitary region, in the otic vesicles and in the blood vessel endothelium. The greatest effect appeared in the pituitary region at 0.75 Gy, while in the otic vesicles it appeared at 0.50 Gy. A dose-effect relationship was established for the DBA lectin affinity of the vascular endothelium. In comparison to DBA, SBA and PNA displayed more extensive staining after irradiation. The reactivity of these lectins appeared especially pronounced on the blood vessels within the central nervous system and in the luminal surface of the ependymal cells. It is of interest that maximal binding for PNA was observed at 0.25 Gy and for SBA at 0.50 Gy at the junctions between neuroepithelial cells.
A PET camera is used to visualize the positron activity induced during protonbeam therapy in order to verify directly the proton-treatment plans. The positron emitters created are predominantly the 15O and 11C, whose total activity amounts to 12 MBq after an irradiation with 85 MeV protons, delivering 3 Gy in a volume of approximately 300 cm3. Although this method is a useful verification of patient set-up, care must be taken when deriving dose distributions from activity distributions. Correlation between both quantities is difficult, moreover at the last millimeters of their range, protons will no longer activate tissue. Due to the short half-lives the PET camera must be located close to the treatment facility.
Nowadays, maintenance dialysis can be proposed to patients suffering from myeloma with end-stage chronic renal failure. We report here data from eight patients dialysed either by hemo- (6) or peritoneal dialysis (2), together with chemotherapy in half of them. Six patients died; the longest survival has been about 6 years. The main cause of morbidity was sepsis, especially in peritoneal dialysis patients; therefore we now favour hemodialysis in patients exposed to aggressive chemotherapy. We think dialysis justified in all cases, including those with high tumor mass, in order to expect the effect of chemotherapy; then, provided good response to drugs, further survival can be consistently improved. Once on maintenance dialysis, main drawbacks for these patients are cardiovascular complications (AL amyloidosis) and above all anemia; the latter however can be markedly improved, thanks to erythropoietin therapy which provides these patients with much better quality of life.
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1. The acute effects of a single oral dose of sinorphan (100 mg), an inhibitor of neutral endopeptidase, on the plasma atrial natriuretic factor level and the fractional excretion of sodium were examined in 12 patients with severe chronic renal failure who were not on maintenance haemodialysis and who ingested a normal sodium diet. The drug was administered against placebo by a double-blind cross-over protocol. 2. Basal plasma atrial natriuretic factor level and fractional excretion of sodium were high (23.2 +/- 3.7 pmol/l and 2.64 +/- 0.38%, respectively). Sinorphan inhibited plasma neutral endopeptidase activity by 68-75% 30 min after ingestion. This effect persisted for at least 4 h. There were simultaneously increases in plasma atrial natriuretic factor and cyclic GMP levels to 1.9 and 1.4 times the basal values, respectively. Fractional excretion of sodium increased during the second and third hour periods after ingestion of the drug with a peak of 1.9 times the basal value in the second period. Changes in fractional excretion of sodium were significantly correlated with those in plasma atrial natriuretic factor and cyclic GMP levels. Plasma aldosterone level, creatinine clearance and mean blood pressure were unchanged, whereas plasma renin activity increased slightly. An increase in urinary cyclic GMP excretion was observed in parallel with the increase in plasma cyclic GMP level.(ABSTRACT TRUNCATED AT 250 WORDS)
Two patients with ankylosing spondylitis were found to have IgA nephropathy and leucocytoclastic cutaneous vasculitis. Immunofluorescence showed perivascular deposition of IgA in the skin of one patient and in the mesangium of both patients. Such an association has been reported only once before. This supports the concept of abnormal IgA immune stimulation in the pathogenesis of ankylosing spondylitis.
To test the ability of ketone bodies to inhibit myocardial fatty acid oxidation in vivo, the myocardial clearance kinetics of [1-11C]palmitate was assessed with positron emission tomography in six fasted volunteers and six instrumented dogs, studied repeatedly before and during infusion of 3-hydroxybutyrate (17 mumol.kg-1 x min-1). With the use of multiexponential fitting of tissue time-activity curves, the size, half time (T1/2), and index of the early rapid phase of 11C myocardial clearance, reflecting palmitate oxidation, were calculated. In humans, the relative size (-28%, P < 0.001) and index (-37%, P < 0.01) of the early rapid phase decreased significantly during infusion of 3-hydroxybutyrate, consistent with decreased fatty acid oxidation. Paradoxically, T1/2 decreased from 10.1 +/- 1.6 to 7.4 +/- 1.1 min (P < 0.01). To elucidate possible mechanisms, multiple coronary arteriovenous samples were obtained from the dogs to assess the efflux of oxidized and nonmetabolized tracer. Infusion of 3-hydroxybutyrate resulted in decreased myocardial [11C]CO2 production (-40%, P < 0.05) and reduced palmitate retention (-38%, P < 0.05). In three dogs, the arteriovenous difference in radiolabeled palmitate became negative 10 min after injection, indicating backdiffusion of nonmetabolized tracer from the myocardium. Thus a steady-state infusion of 3-hydroxybutyrate, resulting in physiological plasma levels, alters [1-11C]palmitate kinetics in vivo by decreasing myocardial long-chain fatty acid oxidation and by increasing backdiffusion of nonmetabolized tracer.