Controlled active motion following primary flexor tendon repair: a prospective study over 9 years.

One hundred and thirty patients with 339 divided flexor tendons affecting 208 fingers were studied prospectively between 1988 and 1996, to assess a regime of primary flexor tendon suture and active postoperative motion, combined with a modified Kleinert dynamic traction splint. The tendon suture technique used was a high-strength multistrand technique using a modified Kessler core and a Halsted peripheral stitch. The results were influenced by the zone in which the tendon was divided, by the physiotherapy and to a lesser extent by the grade of surgeon operating. Overall results by Strickland criteria were 92% excellent or good, 7% fair and 1% poor. There were 43 complications in 31 patients including five zone 2 ruptures (5.7%) and one further rupture in zone 5. This method of flexor tendon repair requires good physiotherapy and splint-making capability but gives good results with minimal need for further surgery.

Primary nerve repair: strength of repair with different gauges of nylon suture material.

Cadaveric median nerves were divided and repaired with interrupted epineural sutures, as in normal clinical practice, using three different gauges of nylon monofilament material. Tensile testing of the nerve repairs showed that, of these three gauges, 9/0 (0.3 metric) sutures were preferable: gap formation at the repair site occurred at the highest force. Finer gauge (10/0) sutures snapped at a lower force, while thicker (8/0) sutures were less consistent and pulled out of the nerve tissue.

Flexor tendon repair: significant gain in strength from the Halsted peripheral suture technique.

A biomechanical study in vitro has evaluated a new modification of the core and peripheral suture technique for flexor tendon repair. Groups of repairs were conducted in cadaver tendons, using a core suture alone, a core suture with a simple running surface suture and a new modification involving a 'Halsted' horizontal mattress technique for the peripheral stitch. The Halsted modification increased the load at which a visible gap formed by 93%, the load at which a 2 mm gap formed by 77%, and the maximum strength by 89%. This increase was due to the technique; it did not depend on the suture material used. The bulk of the tendon repair was not significantly greater with the Halsted modification.

Inhibitory effect of a selective thromboxane A2 receptor antagonist, EP 092, on platelet aggregation in whole blood ex vivo and in vivo.

1. The inhibitory effect of a selective prostaglandin H2 (PGH2)/thromboxane A2 receptor antagonist, EP 092, on platelet aggregatory responses in whole blood ex vivo (guinea-pig: Rhesus monkey) and intravascular aggregation in vivo (rabbit) has been investigated. 2. Collagen (0.1-10.0 micrograms ml-1) caused a concentration-dependent decrease in single platelet count in samples of both guinea-pig and Rhesus monkey citrated whole blood incubated ex vivo. EP 092 administered to guinea-pigs by intravenous (0.1-3.0 mg kg-1) or oral (1.0-10.0 mg kg-1) routes significantly inhibited the platelet responses to collagen (ED50 values 1.3 +/- 0.2 and 1.4 +/- 0.2 mg kg-1 respectively). Similar potency against collagen-induced whole blood aggregation was observed in Rhesus monkey blood samples following EP 092 given orally (ED50 0.9 +/- 0.3 mg kg-1). 3. The duration of action of EP 092 against collagen aggregatory responses ex vivo in both guinea-pigs and Rhesus monkeys was between 3 and 6 h following oral administration at 3.0 mg kg-1. 4. The inhibitory activity demonstrated by EP 092 against collagen-induced aggregation of Rhesus monkey whole blood ex vivo was not accompanied by any significant reduction in thromboxane A2 formation except at the highest dose tested (10 mg kg-1). 5. The intravascular aggregatory response induced by collagen or thrombin in the anaesthetized rabbit was significantly inhibited by an intravenous infusion of EP 092 (10 mg kg-1). EP 092 appeared less potent and its effect was of shorter duration in this preparation compared with its inhibitory effect on ex vivo aggregation, being evident immediately after infusion of drug but not after a further 30 min. 6. It is concluded that collagen-induced platelet aggregatory response in guinea-pig and Rhesus monkey whole blood ex vivo and rabbit in vivo exhibit a thromboxane-dependent component which can be inhibited in a dose-related fashion by pretreatment with the thromboxane antagonist EP 092. In the rabbit, moreover, the data support the possibility of a role for thromboxane in the intravascular aggregatory response to thrombin.

Thromboxane synthase inhibitors. Synthesis and pharmacological activity of (R)-, (S)-, and (+/-)-2,2-dimethyl-6-[2-(1H-imidazol-1-yl)-1-[[(4-methoxyphenyl)- methoxy]methyl]ethoxy]hexanoic acids.

A series of substituted omega-[2-(1H-imidazol-1-yl)ethoxy]alkanoic acid derivatives were synthesized and evaluated for their ability to inhibit thromboxane synthase both in vitro and in vivo. Compound 13 was identified as a potent and selective competitive inhibitor of human platelet thromboxane synthase having a Ki value of 9.6 X 10(-8) M. In collagen-treated human whole blood, 13 potentiated levels of 6-keto PGF1 alpha. Enantiospecific syntheses afforded the R and S enantiomers of 13, of which the S enantiomer 13b was the more potent. Compounds 13 and 13b were potent in vivo inhibitors of thromboxane synthase with good oral activity and duration of action.

Primary flexor tendon repair: the mechanical limitations of the modified Kessler technique.

The aim of primary suture of flexor tendons in the hand is to achieve full function as soon as possible with a one stage operation. Much interest has been aroused by this subject and more recently by the possibility of improving results by postoperative active movement of the repaired tendon. We report the results of mechanical testing of the modified Kessler suture which suggests that the peripheral stitch is an important structural component of the suture. It is not merely a 'tucking in' stitch, but is essential to prevent very early gap formation. Steel is the best material for the central or core part of the suture. Cautious active postoperative movements may be possible using the modified Kessler suture, but within a narrow range of safety and with careful supervision.

Effect of calcium and calcium antagonists on [3H]-Paf-acether binding to washed human platelets.

[3H]-Platelet activating factor (Paf-acether, 1-O-octadecyl-2-acetyl-sn-glycero-3-phosphocholine) binds to washed human platelets in a specific, dose-dependent, and saturable manner. Scatchard analysis reveals a high affinity site with a KD value of 0.25 +/- 0.033 nM (245 +/- 30 sites per platelet), and a second low affinity site with a KD value of 9.22 +/- 1.17 nM (1616 +/- 165 sites per platelet). Binding to the high affinity site is independent of buffer calcium concentration, inhibited on an equimolar basis by unlabelled 1-O-octadecyl-Paf-acether, but remains unchanged in the presence of 1-O-octadecyl-lyso-Paf-acether. The relative inhibitory effect of four calcium antagonists on [3H]-Paf-acether high affinity binding correlates closely with their respective anti-aggregatory activity against Paf-acether induced responses in human PRP; order of potency being (+)-cis diltiazem greater than (+/-)-verapamil greater than (-)-cis diltiazem greater than nifedipine. In the case of (+)-cis diltiazem, the effect is competitive, stereo-specific and progressively reversed by addition of calcium (1.0 mM and 5.0 mM). A close spatial relationship may thus exist between the Paf-acether receptor and membrane calcium channels in the human platelet.

Specific binding of [3H]-1-O-octadecyl Paf-acether to washed human platelets.

[3H]-Paf-acether binds to washed human platelets in a dose-dependent manner. Scatchard analysis reveals two distinct binding sites; a high affinity site with a KD value of 0.259 +/- 0.33 nM (245 +/- 30 sites per platelet) and a lower affinity site with a KD value of 9.22 +/- 1.17 nM (1616 +/- 165 sites per platelet). Association of 3H-Paf-acether to the high affinity receptor is rapid, being maximal within two minutes and remaining constant for at least twenty minutes. Dissociation from the low affinity receptor is also rapid (t1/2: less than 10s) whereas dissociation from the high affinity site is significantly slower (t1/2 : approximately 70s). [3H]-Paf-acether binding is inhibited by unlabelled (R)-C16-Paf (IC50: 0.08 +/- 0.01 nM) greater than (R)-C18-Paf (0.48 +/- 0.03 nM) greater than (RS)-C18-Paf (1.06 +/- 0.19 nM), but remains unchanged in the presence of lyso-C18-Paf at 3.0-300 nM. [3H]-Paf-acether binding and its inhibition by unlabelled (R)-C18-Paf-acether is independent of buffer Ca2+ within the range 0-5.0 mM.

Arthrodesis of the knee after failed knee replacement.

Arthrodesis of the knee is sometimes needed for failed total knee replacement, but fusion can be difficult to obtain. We describe a method of arthrodesis that uses the simple, inexpensive, Portsmouth external fixator. Bony union was obtained in all six patients treated with this technique. These results are compared with those obtained by other methods of arthrodesis.

The fate and impact of oil and oil-dispersant mixtures in freshwater pond ecosystems: introduction.

Oil and oil-dispersant mixtures were added to the surface waters of a series of man-made ponds. The fate of the oil and dispersant (Norman Wells crude and Corexit 9527 respectively) were studied as well as the impact of the added chemicals on the ponds' ecosystems. Elements of the ecosystems studied include bacteria, fungi, phytoplankton, periphyton , proto- and mesozooplankton , zoobenthos and surface insects. In addition a number of water quality parameters were regularly monitored. Comparisons were made between oil-treated and control ponds, as well as oil-dispersant treated and oil and/or control ponds. This paper describes the experimental set up and provides a summary of the findings reported in the following five papers.

Impact of oil and oil-dispersant mixtures on the fauna of freshwater ponds.

In a series of 5 artificial ponds, one was treated with a nomial concentration of 100 ppm of crude oil, two others were treated with a nominal 100 ppm of oil and 20 ppm of dispersant. Mesozooplankton populations were reduced in the oil-treated pond relative to the control pond, and eliminated in the oil-dispersant ponds. This condition persisted until the following year when the mesozooplankton was similar in all ponds. The protozooplankton experienced species shifts with Halteria and Strobilidium being eliminated initially in all treated ponds, but Halteria was collected in samples the following spring. Other protozoans such as thecamoebae increased in the treated ponds, while others, like zooflagellates , did not appear to be affected by the chemicals. Zoobenthos was affected by treatment, with the number of different types being reduced. The zoobenthos had recovered in one of the treated ponds the following spring, and that in the other treated ponds were recovering. Surface insects were eliminated after treatment, but recolonized during the next spring. Nekton were initially reduced by treatment. The population changes are discussed with respect to the fate of oil.

Hearing preservation in patients with acoustic neuromas via the middle fossa approach.

Twenty patients with acoustic neuromas were operated on in an attempt to preserve hearing. These patients were selected from a series of approximately 300 patients seen from May 1975 to March 1979. All patients were operated on via the middle fossa approach. Hearing was preserved in approximately 35% of the patients. Preoperative and postoperative audiograms were performed on all patients. Tumor size ranged from 5 to 15 mm. These current cases are compared and added to our previous series of 17 cases (10 with hearing preserved) from a series of 500 acoustic neuromas reported elsewhere. Selection of patients, audiogram results, details of the middle fossa procedure, and work by other investigators are discussed.