Intra-arterial prostacyclin compared to Praxilene in the management of severe lower limb ischaemia: a double blind trial.

The effectiveness of a 72 h. intra-arterial prostacyclin infusion has been compared to that of naftidrofuryl oxalate (Praxilene) in a double blind study of 29 patients with ischaemic rest pain in 30 legs. Long-term relief of symptoms was achieved in 14 legs (47%) and major limb amputation avoided in 18 (60%). No significant difference was demonstrated between the results of prostacyclin infusion and those of Praxilene.

Prevention and treatment of venous ulceration.

Venous ulcers are related to incompetence of the direct calf and ankle perforating veins, the majority of which follow deep vein thrombosis. Prevention of the latter by intravenous micro-dose heparin (1 unit/kg/hour) is effective, safe and inexpensive. Its efficacy has been proved in two controlled clinical trials. Venous ulcers have been treated by perforating vein ligation, with saphenous ligation and stripping where necessary, and with the addition of permanent knee-length elastic compression stockings in patients with femoro-popliteal incompetence. This regimen has achieved a 92% long-term success rate in patients without rheumatoid arthritis.

[Should the incontinent saphenous veins be stripped down to the ankle?]. / Doit-on stripper les saphènes incontinentes jusqu'a la cheville?

Long strippings (groin to ankle) are subject to an unacceptable percentage (23-58%) of neurological complications due to traumatism of the saphenous nerve. A simple saphenofemoral ligation avoids these complications, but the incidence of varicose relapse is nevertheless still about 60%. Our long saphenal strippings practised on 96 legs in 71 patients were followed in 4.2% by saphenous neurological symptoms, with varicose relapse in 12.5%; this is half as many as in sclerosant injection therapy.

The effective management of venous ulceration.

The importance of the direct perforating veins of the lower leg in the aetiology of venous ulceration is supported by the results of a 6-year study of 77 patients with 109 ulcerated legs. Incompetent perforating veins were demonstrated by examination and Doppler ultrasound, and confirmed at operation, in 108 legs. Subfascial ligation of these veins, with stripping of incompetent saphenous veins when necessary, was followed by elastic compression stockings in 44 legs (40 per cent) in which deep vein incompetence was demonstrated by non-invasive methods and phlebography. Some 91 ulcers (84.3 per cent) remain healed (76 per cent greater than 3-year follow up). Eight patients with rheumatoid arthritis in addition to venous incompetence had a 75 per cent failure rate. If these patients are excluded, 88 (92 per cent) of 96 ulcerated legs remain healed. It is submitted that these results support the argument for the importance of perforating vein incompetence in the aetiology of venous ulceration. They also suggest that a more optimistic attitude towards treatment is justified.

Prevention of postoperative leg vein thrombosis by electrical muscle stimulation. An evaluation with 125I-labelled fibrinogen.

In a prospective trial of preventing deep vein thrombosis electrical stimulation of the calf muscles of one leg was used in 110 patients undergoing major surgery. Deep vein thrombosis was detected by means of the (125)I-fibrinogen uptake test in nine of the stimulated legs and in 23 of the unstimulated legs. It is suggested that this technique, which is both simple and effective, should be used on all patients undergoing major surgery.

Picosecond fluorescence decay of tryptophans in myoglobin.

The fluorescence decay characteristics of Mb, MbCO, metMb (sperm whale), metMb (yellowfin tuna), and their apo derivatives were determined by using a picosecond streak camera and time-correlated single photon counting. The emission is dominated by tryptophans that transfer their energy to the heme on a subnanosecond time scale. Sperm whale Mb and derivatives have two tryptophans and their decays can be interpreted mainly as two exponentials, one of ca. 20 ps and the other of 130 ps, whereas tuna Mb has one tryptophan and its emission is nonexponential but dominated by one component of 31 ps. These results along with Förster energy transfer calculations allow us to assign the ca. 30-ps emission to Trp-14 and the 130-ps emission to Trp-7 in Mb. The streak camera was modified to determine the decay of the fluorescence anisotropy. In metMb (tuna) the fluorescence anisotropy decays in 100 ps, which is postulated to result from rapid motion of the Trp-14. Because energy transfer was used to gate the anisotropy, the fast motion of Trp-14 is proposed to correspond to only 10% of the equilibrium distribution of molecules.

Ultra-low dose intravenous heparin in the prevention of postoperative deep-vein thrombosis.

Heparin (1 IU kg-1 h-1) given intravenously for 3-5 days during and after operation in a double-blind randomised study, significantly reduced the frequency of deep-vein thrombosis detected by 125I-fibrinogen uptake, and pulmonary embolism. 22% (11/50) control patients and 4% (2/45) patients receiving heparin had deep-vein thrombosis or pulmonary embolism. Heparin administration was not associated with any increase in preoperative or postoperative bleeding.

30-fs pulses tunable across the visible with a 100-kHz Ti:sapphire regenerative amplifier.

A 100-kHz mode-locked Ti:sapphire-seeded regenerative amplifier pumping an optical parametric amplifier generates femtosecond pulses tunable from 470 to 710 nm. This output was compressed with a pair of prisms to bandwidth-limited pulses of 80- to 40-fs duration and more than 150 nJ of energy. These tunable pulses were then bandwidth expanded through self-phase modulation in bulk material and further compressed to less than 30-fs duration.

Thigh length versus knee length stockings in the prevention of deep vein thrombosis.

Above-knee graduated compression stockings are effective in preventing postoperative deep vein thrombosis, but are more expensive and less acceptable than below-knee stockings. One hundred and fourteen patients undergoing major abdominal surgery were randomly allocated to wear above-knee or below-knee graduated compression stockings. Deep vein thromboses were diagnosed by isotope uptake in three of 56 patients (5.4 per cent) in the above-knee group and one of 58 patients (1.7 per cent) in the below-knee group. These differences are not statistically significant. Results suggest that below-knee stockings are as effective as above-knee in the prevention of postoperative deep vein thrombosis.

2.3-ps pulses from a Kerr-lens mode-locked lamp-pumped Nd:YLF laser with a microdot mirror.

Pulses as short as 2.3 ps have been generated by passive mode locking of a lamp-pumped Nd:YLF laser with a microdot mirror mode locker for Kerr-lens mode-locking (KLM) saturable absorber action and a compact Gires-Tournois interferometer for dispersion compensation. KLM was initiated with an acousto-optic modulator. Average output powers of 800 mW have been achieved. This result demonstrates the potential use of KLM for generating near-bandwidth-limited pulses from high-power lamp-pumped sources.

Light reflection rheography: a simple noninvasive screening test for deep vein thrombosis.

PURPOSE: The clinical diagnosis of deep vein thrombosis (DVT) is unreliable. Contrast phlebography (CP) continues to be the gold standard, but it is invasive. Although duplex ultrasonography is an accurate, noninvasive alternative, it is expensive, technically demanding, and time-consuming. We postulated that light reflection rheography (LRR), a noninvasive method of assessing the quantity and rate of venous emptying, might be a reliable and inexpensive bedside approach to screening patients with clinically suspected DVT. METHODS: With LRR, infrared light is beamed onto the skin, and the amount of backscattered rays are detected, which indirectly measures the amount of blood present in a volume of the epidermis beneath the LRR probe. Applied to the calf muscle pump, LRR can provide a noninvasive method of assessing blood volume changes in the sample area of skin, in response to venous hemodynamic changes in the lower limb. RESULTS: Sixty-nine limbs in 61 patients undergoing CP for clinically suspected DVT over a period of 12 months also underwent LRR, either just before or within 24 hours of undergoing phlebography. The criteria for diagnosing DVT on CP were presence of filling defect or nonfilling of a venous segment. The result of LRR was considered positive for DVT if the rate of venous emptying was 0.35 or less. With these criteria a sensitivity of 96.4% and specificity of 82.9 were obtained. This resulted in a positive predictive value of 79% and a negative predictive value of 97.1%. CONCLUSIONS: LRR is a simple, inexpensive, and noninvasive bedside test that takes 10 minutes to perform. It is highly sensitive with a high negative predictive value, detecting most cases of DVT, reliably ruling out DVT, and eliminating the need for more time-consuming and costly studies. Therefore it seems to be an appropriate screening test in patients with clinically suspected DVT.