Biomedical subjects

R Thys

Publications and source records attributed to R Thys.

At least 19 recordsLinked to original sources

PubMed1991

[Tibiotarsal and subtalar instability of the ankle. Importance of an original dynamic test in the treatment choice. Experimental study and clinical application].

Various ligamentoplasties are available allowing formation of new proprioceptive chains in cases of failure of physiotherapy. Most of these plasties sacrifice half or all of the fibulolateral tendon, causing stiffness of the subtalar joint. This is a too serious complication to accept for simple tibiotarsal instability: hence the importance of preoperative assessment to determine the type of plasty most appropriate for each type of instability. We have designed an adjustable boot, linked to a dynamometer by means of a metal rod, with a radiological marker attached to the boot, to measure subtalar mobility preoperatively. We studied this boot with the ankles of 15 cadavers, on which we sectioned the ligaments of the tibiotarsal and subtalar joints to measure the degree of laxity. Accurate assessment is possible if the mobility of the tibiotarsal and subtalar joints is measured in cases of acute sprain, in particular in isolated lesions of the anterior talofibular ligament and lesions of the calcaneofibular ligament; or in chronic instability, including: purely tibiotarsal, purely subtalar, and mixed types. This method allows optimal therapeutic choice.

Ankle Joint↗

PubMed1990

[Osteosynthesis of lesions of the proximal femur using dynamic screw plates. Multicenter study: 1871 cases].

A series of 1871 lesions of the upper end of the femur were treated in 32 hospitals in Belgium using a dynamic hip screw. Unstable pertrochanteric fractures were present in 34.4%. The remainder were intracapsular, extracapsular and subtrochanteric fractures, or tumour deposits. The patients were elderly, infirm and usually female. A fortnight after operation 89% were sitting, 64% could walk with a frame and 31% with crutches. Failure of fixation occurred in 3.6% of cases overall, with 6.6% in unstable fractures. Perioperative screw compression did not appear helpful, since most fractures settled after operation.

Adult↗

PubMed1990

[Reflections on a small series of cementless total hip prostheses].

We report on our series of 48 patients with uncemented hip prostheses, with an average follow-up of 3 years. The clinical results, according to the Merle d'Aubigné's classification, are comparable to those obtained with cemented prostheses except for transitory pain, very often localized to the lateral aspect of the thigh, which seems to be correlated with the bone adaptation to the implant. Radiological findings are valuable in the assessment of long-term results with uncemented prostheses. During the operation, it is of utmost importance that the surgeon obtain a very tight fit of the prosthesis into the bone, which must be confirmed on postoperative X-ray. Under such conditions, the radiological appearance remains the same, showing a condensation line outlining the cup and absence of radiolucent lines along the stem. On the other hand, cortical thickening, bony condensation around the tip of the stem and sclerotic lines are the radiological evidence of bone adaptation to the prosthesis. They are not indicative of a less good result. Finally, radiolucent lines wider than 1 millimeter, extending along the stem, or a progressive sinking of the femoral component are the radiological signs of implant instability. In these rare cases, the prognosis may be compromised.

Adolescent↗

PubMed1988

Transfer of functional insulin receptors to receptor-deficient target cells.

Purified human insulin receptors incorporated into phospholipid vesicles have previously been shown to retain insulin binding as well as insulin-stimulated beta-subunit autophosphorylating activity. These vesicles were used as a vehicle to transfer receptors to the insulin receptor-deficient Madin-Darby canine kidney (MDCK) cell line. Fusion of control [14C] dioleoylphosphatidylcholine-labeled phospholipid vesicles with MDCK cells was found to be dependent on both the amount of time and the concentration of polyethylene glycol used for fusion. Optimal insulin receptor transfer, as determined by recovery of [125I]insulin binding, occurred when MDCK cells were incubated for 45 min at 37 C in the presence of 15% polyethylene glycol plus receptor-containing vesicles. Scatchard analyses for insulin receptor binding before and after vesicle fusion demonstrated no postfusion alteration in insulin receptor affinity and a 10-fold increase in the number of insulin receptors present in the MDCK cells. Fusion transfer of insulin receptors to MDCK cells rendered the cells sensitive to insulin (10-100 nM) for stimulation of glycogen synthesis. Chloroquine (0.1 mM) was found to block endosomal processing of receptor-bound [125I] insulin within 1 h. These findings indicate that insulin receptors function as dissociable units which can be inserted into target plasma membranes with resultant recoupling to cellular systems.

Animals↗

PubMed1987

High-level expression of human insulin receptor cDNA in mouse NIH 3T3 cells.

In order to develop a simple, efficient system for the high-level expression of human insulin receptors in eukaryotic cells, a full-length human kidney insulin receptor cDNA was inserted into a bovine papilloma virus vector under the control of the mouse metallothionein promoter. After transfection of mouse NIH 3T3 cells with this construct, seven cell lines expressing insulin receptors were isolated; two cell lines had more than 10(6) receptors per cell. The cell line with the highest insulin binding (NIH 3T3 HIR3.5) had 6 X 10(6) receptors with a Kd of 10(-9) M. This level was not dependent on exposure to metals but could be increased further to 2 X 10(7) receptors per cell by addition of sodium butyrate to the culture medium. The alpha and beta subunits had apparent molecular weights of 147,000 and 105,000, respectively (compared to 135,000 and 95,000 in IM-9 human lymphocytes), values identical to those of the alpha and beta subunits of the insulin receptors of nontransformed NIH 3T3 cells. This size difference was due to altered carbohydrate composition, as N-glycanase digestion reduced the apparent receptor subunit size of the transfected cells and IM-9 lymphocytes to identical values. The alteration in N-linked oligosaccharide composition could not be ascribed to differences in the kinetics of posttranslational processing of the insulin receptors, which was comparable to that of other cells studied. The basal rate of glycogen synthesis in the cells overexpressing insulin receptors was increased 4- to 5-fold compared with controls. Low levels of added insulin (0.1 nM) caused a 50% increase in the rate of glycogen synthesis.

Animals↗

PubMed1983