A new torque guide wire

A new guide wire that provides markedly improved torque control is described. It was compared with a conventional guide wire in two models, one simulating a drainage tube with numerous side holes and one, the biliary tree. The new wire was much more easily controlled than the conventional guide wire and passed through both models significantly faster (P less than .01 and P less than .005). Although some deterioration in control was noted when it was inserted through a catheter in vivo, the new torque-control wire still exhibited a definite improvement over conventional wires in directional control.     

Mechanical clot dissolution: new concept

The authors present preliminary data on in vitro mechanical clot dissolution by means of a catheter with a tiny high-speed propeller enclosed in a special housing. Preweighed human blood clots were subjected to the catheter in a test tube with saline at various propeller speeds and durations of application. After filtration of the resultant slurry, the clot residue was weighed and examined histologically. Clot dissolution was found to be related to both the duration and speed of propeller rotation. No fibrin residue was seen after dissolution, although potential embolic material, composed of clumps of cellular debris as large as 208 microns in longest dimension, was found. Mechanical clot dissolution could possibly be used in any natural or synthetic blood vessel in which there is acute or subacute thrombosis, with fewer complications and lower cost than obtained with traditional methods.     

MR imaging technology: maximizing the signal-to-noise ratio from a single tissue

The pulse-sequence equations for spin-echo magnetic resonance imaging were used to determine interpulse delay times that give the highest signal-to-noise ratio from a single tissue. This theoretical result was then verified experimentally using 1-, 2-, and 5-mM/l copper sulfate solutions imaged on a 0.15-T resistive system. Theoretical analysis determined the spin-echo interpulse delay times that maximize the signal-to-noise ratio from a single tissue as TEopt = TEmin, the minimum echo delay time permitted by the system, and, to a good approximation, TRopt = 1.27 T1 + 1.90 TEmin, with T1 the longitudinal magnetic relaxation time of the tissue. Phantom measurements of the signal-to-noise ratio in a typical imaging system confirmed the theoretically determined TRopt values to within 7%.     

Improved vessel dilator for percutaneous catheterization

Three commercial vessel dilators and a dilator of an improved design were tested during percutaneous catheterization in 16 mongrel dogs to evaluate arterial damage produced with their use. The results indicate that, although all dilators often produce arterial damage, the improved design produced much less damage. In addition, lesions were less severe overall. The dilator has been safely and successfully used in patients for percutaneous vessel catheterization for the past 30 years at the authors' institution.     

P-(3-酰氨基-4-取代苯基-2-吖丁啶酮基-1)-苯乙酸和P-(3-酰氨基-4-取代苯基-2-吖丁啶酮基-1)-苯乙酮的合成及抑制β-内酰胺酶作用

为研究吸电子基团远离环氮的单环β-内酰胺类化合物对β-内酰胺酶的抑制作用,设计与合成了21个新的p-(3-酰氨基-4-取代苯基-2-吖丁啶酮基-1)苯乙酸和p-(3-酰氨基-4-取代苯基-2-吖丁啶酮基-1)苯乙酮类化合物,经元素分析、红外光谱、核磁共振氢谱和质谱证实。生物活性测定表明,其中15个具有游离羧基的水溶性化合物对试验的腊样芽胞杆菌和绿脓杆菌产生的β-内酰胺酶有抑制作用。     

Purging murine leukemic marrow with alkyl-lysophospholipids

Autologous bone marrow transplantation is potentially curative in the treatment of acute leukemia if residual leukemic cells in the marrow can be eliminated prior to transplantation. We studied the purging effects of a synthetic alkyl-lysophospholipid (ALP) on marrow containing leukemic cells from a transplantable myelomonocytic leukemia (WEHI-3B) in BALB/c mice. Simulated remission bone marrow containing 2% leukemic cells treated in vitro with 20 and 100 micrograms/mL of ET-18- OCH3 (1-octadecyl-2-methyl-sn-glycerol-3-phosphocholine) significantly prolonged survival of lethally irradiated transplanted recipients. At a dose of 100 micrograms/mL, 88% of the mice survived for the duration of the experiment (approximately five months). Autopsies showed that 25% of these survivors had microscopic evidence of leukemia. Thus, in vitro treatment of marrow eliminated leukemic blasts and spared sufficient normal stem cells to allow hematologic reconstitution. The effect of ET- 18-OCH3 is not entirely selective for leukemic cells. A spleen colony assay showed that ALP has some cytotoxic effect on normal hematopoietic stem cells.     

Effect of natural killer cells on syngeneic bone marrow: in vitro and in vivo studies demonstrating graft failure due to NK cells in an identical twin treated by bone marrow transplantation

Bone marrow transplantation for severe idiopathic aplastic anemia was undertaken in a patient, using his monozygotic twin brother as the donor. In spite of the use of syngeneic bone marrow, failure of engraftment occurred on two occasions. In vitro studies demonstrated that natural killer (NK) cells from the recipient markedly inhibited the growth of donor bone marrow granulocyte progenitor cells. On a third attempt, successful bone marrow engraftment was achieved following high-dose cyclophosphamide, which has previously been shown to be inhibitory to NK cells. We conclude that NK cell activity may play an important role in bone marrow failure as well as being responsible for at least some cases of aplastic anemia.