Effect of suture material on gap formation and failure in type 1 FDP avulsion repairs in a cadaver model.

BACKGROUND: An in vitro cyclical testing simulating a passive mobilisation protocol was used to compare repair of flexor digitorum profundus tendon with modified-Bunnell two-strand pullout technique using a monofilament (Prolene), braided polyester (Ethibond) and a synthetic polyfilament ensheathed by caprolactan (Supramid) sutures. METHODS: Eighteen fresh-frozen cadaveric fingers were randomly divided into three repair groups (n = 6); modified-Bunnell technique with 3/0 Prolene, Ethibond or Supramid. After repair, specimens were cyclically loaded from 2 to 15N at 5N/s, for a total of 500 cycles. Gap formation at the tendon-bone interface was assessed every 100 cycles. Samples were tested to failure at the completion of 500 cycles. FINDINGS: All sutures held in all specimens during cyclic testing. The gap formation after 500 cycles was greatest with Prolene suture (6.8 mm, SD 1.2) followed by Supramid suture (4.0 mm, SD 1.1) and Ethibond suture (1.7 mm, SD 1.7) (P < 0.05). Repairs with Supramid displayed higher failure load (52.7 N, SD 5.5) as compared to Prolene (37.6N, SD 4.7) (P = 0.001) but not compared to Ethibond (44.9 N, SD 7.1). The failure loads between Prolene and Ethibond did not differ (P = 0.130). INTERPRETATION: Gap formation with Ethibond was significantly lower compared to Supramid and Prolene. The four strand nature of the Supramid repair was superior to Prolene but did not differ compared to Ethibond with respect to failure load. Prolene is the least favourable suture when considering gap formation and failure load, while Ethibond is the most favourable.

The effect of mitek anchor insertion angle to attachment of FDP avulsion injuries.

Flexor digitorum profundus (FDP) tendon avulsions, although uncommon, are not infrequent injuries. A widely accepted method of treating Type 1 FDP avulsions is a pullout suture tied over a button on the nail plate. The external dorsal button is often a source of inconvenience for the patient. Potential risks associated with button use include nail plate deformities, nail fold necrosis and infections tracking along the sutures. The use of small suture anchors provides a satisfactory alternative, because buried fixation avoids these potential complications. This in vitro, biomechanical study examined the influence of the anchor orientation on the properties of the repaired FDP tendon using human cadavers.

Temperature dependence of active tension in mammalian (rabbit psoas) muscle fibres: effect of inorganic phosphate.

1. The effect of added inorganic phosphate (P(i), range 3-25 mM) on active tension was examined at a range of temperatures (5-30 degrees C) in chemically skinned (0.5 % Brij) rabbit psoas muscle fibres. Three types of experiments were carried out. 2. In one type of experiment, a muscle fibre was maximally activated at low temperature (5 degrees C) and its tension change was recorded during stepwise heating to high temperature in approximately 60 s. As found in previous studies, the tension increased with temperature and the normalised tension-(reciprocal) temperature relation was sigmoidal, with a half-maximal tension at 8 degrees C. In the presence of 25 mM added P(i), the temperature for half-maximal tension of the normalised curve was approximately 5 degrees C higher than in the control. The difference in the slope was small. 3. In a second type of experiment, the tension increment during a large temperature jump (from 5 to 30 degrees C) was examined during an active contraction. The relative increase of active tension on heating was significantly higher in the presence of 25 mM added P(i) (30/5 degrees C tension ratio of 6-7) than in the control with no added P(i) (tension ratio of approximately 3). 4. In a third type of experiment, the effect on the maximal Ca(2+)-activated tension of different levels of added P(i) (3-25 mM) (and P(i) mop adequate to reduce contaminating P(i) to micromolar levels) was examined at 5, 10, 20 and 30 degrees C. The tension was depressed with increased [P(i)] in a concentration-dependent manner at all temperatures, and the data could be fitted with a hyperbolic relation. The calculated maximal tension depression in excess [P(i)] was approximately 65 % of the control at 5-10 degrees C, in contrast to a maximal depression of 40 % at 20 degrees C and 30 % at 30 degrees C. 5. These experiments indicate that the active tension depression induced by P(i) in psoas fibres is temperature sensitive, the depression becoming less marked at high temperatures. A reduced P(i)-induced tension depression is qualitatively predicted by a simplified actomyosin ATPase cycle where a pre-phosphate release, force-generation step is enhanced by temperature.

Gadopentetate dimeglumine excretion into human breast milk during lactation.

PURPOSE: To analyze the amount of gadopentetate dimeglumine excreted into human breast milk following intravenous injection of a clinical dose. MATERIALS AND METHODS: Gadopentetate dimeglumine was injected intravenously in 20 lactating women (23-38 years of age). Breast-feeding was interrupted for at least 24 hours. Serial samples of expressed milk were collected and analyzed for gadolinium concentration by means of inductively coupled plasma atomic emission spectrometry at a wavelength of 342.247 nm. RESULTS: The cumulative amount of gadolinium excreted in human breast milk during 24 hours was 0.57 micromol +/- 0.71 (SD; range, 0.05-3.0 micromol). The excreted dose was thus less than 0.04% of the administered intravenous dose (range, 0.001%-0.04%; mean, 0.009% +/- 0.010) for all cases. CONCLUSION: Less than 0.04% of administered gadopentetate dimeglumine is excreted into human breast milk. The amount transferred to a nursing infant orally would be far more than 100 times less than the permitted intravenous dose (200 micromol per kilogram of body weight) for neonates. The recommendation of a 24-hour suspension of breast-feeding for lactating women should thus be reconsidered.

In situ measurements of skeletal muscle power output using new capacitive strain gauge.

Experiments are described in which a fatigue index is determined for the latissimus dorsi muscle of sheep in situ, using capacitive strain gauges. Parallel experiments for invasive and non-invasive measurements are conducted, measuring global contraction and relaxation rates and shortening duration for paced muscle. The results show that, above one pulse per burst (5 V, 100 microseconds pulsewidth), contraction rates (62 +/- 11 mm s-1) and relaxation rates (50 +/- 7 mm s-1) are constant for unloaded muscle. For one animal, fatigue testing with a 2.5 kg load at six pulses per burst shows shortening rates increasing to a maximum (80 mm s-1) after 30 s and reducing to 5 mm s-1 after 150 s. The decrease in shortening amplitude is used as a fatigue index, log displacement against time. Power output is load dependent, measuring 4.7 W kg-1 with a 2.5 kg load. There is good agreement between the invasive and non-invasive measurements, thus providing a method for monitoring changes in muscle parameters non-invasively during future pacing transformation.

[Antiaggregatory and anticoagulant effects of oligoamines. 12. Alkyl- and arylalkyl- derivatives of putrescine, spermidine and spermine]. / Antiaggregatorische und anticoagulante Eigenschaften von Oligoaminen, 12. Mitt. Alkyl- und Arylalkylderivate von Putrescin, Spermidin und Spermin.

Eleven lipophilic derivatives of the title biogenic amines and 28 structurally related triamines and tetramines have been synthesized. Twenty-three of them inhibited the platelet aggregation induced by collagen at an IC50 between 8 mumol/L and 30 mumol/L. Five compounds prolonged the one stage thromboplastin time (Quick) by 7s or more at 100 mumol/L. The antiplatelet and anticoagulant effect do not run parallel. The relationship between the effects observed and the chemical structure of the oligoamines has been elucidated.