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Biomedical subjects

B Stanczewski

Publications and source records attributed to B Stanczewski.

At least 19 recordsLinked to original sources
PubMed1982

Evaluation of the Tamari-Kaplitt LVAD.

Experience with a modern inexpensive, unichambered heparinized "left ventricular assist device" in the closed chest unheparinized dog is described. The pumps were driven with EKG activated air drives. These functioned well. The major physiologic problems were absolute limitation of inflow and late mural and valve disk thrombus formation at pump times approaching 5 to 6 hrs, under the limitations of the experiment. The inexpensiveness of this LVAD, its obvious practicality in terms of application as a counter pulsator in human open heart surgery and now in experimental animals, provides some hope that an inexpensive, practical, functional preanticoagulated LVAD of this type may ultimately result in a significant improvement in the utility and cost effectiveness of this approach to left ventricular failure.

Animals↗
PubMed1981

A clinical experience with the NCGT graft.

A comparison of 130 grafts done in 101 patients included 47 veins, 25 Johnson & Johnson dialdehyde-starch-tanned collagen prostheses, and 58 NCGT grafts that had been followed for a 40-month period. This study had documented the fact that in spite of frequent poor runoff, a useful result is provided by the NCGT graft apparently due in part to its built-in nonthrombogenic structure providing a cumulative patency of 73%. The patency rate was even superior with venous bypasses. Therefore, we still feel that the autogenous vein provides the most useful bypass conduit available in vascular reconstruction. In situations where a vein could not be used or was not available the NCGT graft offers an equally useful nonthrombogenic surface to maintain prolonged patency. Thus, collagen appropriately modified can provide a useful prosthesis in vascular reconstruction.

Aged↗
PubMed1981

Experiments with nonthrombogenic and thrombogenic collagen in laboratory and clinical use.

The Negatively Charged Glutaraldehyde Tanned (NCGT) graft has now encompassed 12 years in experimental animals and five years clinical experience with 134 grafts in man. It demonstrates that vessel wall structure, interface-charge, electric potential and polarity at the blood intimal interface are critical in the prevention of intravascular thrombosis in both vascular tree and vascular prosthetic grafts. The hemostatic properties of a new solvating positively charged hemostatic collagen (superstat) were first evaluated in 30 dogs using a skin pouch preparation and incisions in spleen and liver. The results were striking. The effectiveness in man has been determined by more than 130 applications in various surgical procedures. In several, it was used in emergencies to produce hemostasis which could not be obtained by any other material available. Hemostasis is obtained rapidly with Superstat, an effective electron sink, even in heparinized patients. Finally, the material has demonstrated that it rapidly produces hemostasis while dissolving, does not develop abnormal adhesions, fibroplasia of foreign body reaction.

Adult↗
PubMed1980

Long-term function of NCGT vascular conduits in a multicenter trial: evaluation of physical chemical parameters.

Our experience with the NCGT graft has now encompassed 12 years in experimental animals and 4.5 years clinical experience with 134 grafts in man. It has previously been suggested that vessel wall structure, interface-charge, electric potential, and polarity of the blood intimal interface appear critical in the prevention of intravascular thrombosis in all vascular prosthetic bypass grafts. This concept has now been confirmed using ferritin, colloidal iron and fluorescamine intimal labelling. These provide a quantitative special characterization of the surface charges of several grafts, including the NCGT graft. Study indicates that each step in the production of the NCGT graft results in a cumulative increase in the structured negative charge of the vascular interface. The more dense the structured negative charge of the prosthesis, the more resistant is the graft to short and long-term thrombosis in experimental animals and man. The experience has been confirmed with a comparative analysis of implantation results in 105 patients up to 4.5 years with 65 to 70% patency rate over that time interval. Statistical analysis of parameters confirm again that the polarity and structure of the vascular interface is important in the effective function and patency rate of the grafts.

Animals↗
PubMed1980

A new effective intraoperative hemostat - Superstat.

A new effective solvating hemostatic agent, Superstat, has been developed and evaluated in animals and man. It appears to work in part because of its large electron absorbing surface and in part due to the physiologic concentration of contained calcium. The available information from the first 130 patients in which it has been evaluated suggest that it has few, if any, side effects, leaves no residue following use, and is an extremely effective hemostat under most conditions and in all tested operative areas in man. Available data indicate that it has local effects which represent biochemical and ultra-structural interactions with shed blood.

Animals↗
PubMed1979

In vitro and in vivo evaluations of dacron velour and knit prostheses.

Dacron velour and knit prostheses were compared with respect to long-term patency when used as canine aortic implants. These grafts were rated, according to the average numerical value of six equally weighted criteria, in decreasing order of performance: velour I, velour II, circular knit III, velour IV, circular knit V, warp-knit VI, warp-knit VII and VIII, warp-knit IX and warp-knit X. In general, compacting and crimping methods using halogenated hydrocarbons produced the least successful grafts. Grafts of identical brand but compacted and crimped by different methods exhibited different patencies. No true healing of the grafts was observed. Layered deposits of inner fibrous capsule were formed at rates and thicknesses characteristic for each type of graft employed. A functioning Dacron femoral-popliteal bypass removed from a human after 9 months exhibited inner and outer fibrous capsules similar to those from canine implants.

Animals↗
PubMed1976

The haematological hazards of autotransfusion.

Fourteen heparinized dogs were autotransfused from 1-5 to 6 times calculated blood volume. Five animals retransfused 12 litres from an intraperitoneal bleed had marked decreases in all cellular elements, haematuria and a large (82 percent) drop in fibrinogen. All these animals died within 12 hours and post-mortem examination revealed evidence of disseminated intravascular coagulopathy. The dogs in which a smaller volume (3-6 litres) was recycled showed similar, but less devastating, changes. Haematocrit and platelet count dropped by a half and fibrinogen by 20 per cent. A leucocytosis of about 30 000/mm3 occurred within 24 hours. Autotransfusion of salvaged blood which was not allowed extravascular tissue contact significantly lessened these adverse effects. We conclude that the risk of cellular destruction and defibrination in large volume intra-operative autotransfusion is significant and must be weighed against its potential benefits in each case, and that red cell and platelet damage results primarily from extravascular tissue contact and is therefore unavoidable.

Animals↗
PubMed1975

Thromboresistance of glass after glow discharge treatment in argon.

Glow discharge treated (GDT) inorganic materials are sterile and free of all organic contaminants. Such materials implanted in the canine inferior vena cava often demonstrate significant thromboresistance. Standard Pyrex glass tubing was GDT in argon to provide a surface free energy above 70 dynes/cm, slight surface negativity, and other surface-physical modifications of its interface. Chromic acid cleaned lengths of the same tubing, and short segments whose edges were not fire-polished were used as controls. Upon canine implantation, the in vivo results were similar in independent surgical laboratories. The glass was implanted as 1.4 cm long rings or as 5 cm long tubes in separate medical centers according to different protocols. GDT specimens remained patent; all controls accumulated thrombi. A remarkably pure, low critical surface tension, labile protein coating covered all cylindrical lumens after 2 hr in vivo. This coating diminished within 2 weeks and was essentially absent after 480 days, eeven though scanning EM showed evidence of a micron thick luminal film, probably eroding glass. No emboli were found in the implant animal's kidney or lungs at any stage.

Animals↗
PubMed1975

Nonthrombogenic ac polarized copper prosthesis.

In previous studies from our laboratories, it was shown that metals and alloys which register negative potentials in blood vs the normal hydrogen electrode tend to be antithrombogenic while those with positive potentials are invariably thrombogenic. The present paper deals with a novel approach of maintaining an implanted metallic prosthesis at a negative potential. A copper vascular prosthesis in a dog was maintained at cathodic potentials by a small amplitude (+/- 10 mV) high-frequency ac (100 kHz) on the prosthesis. The prostheses were removed after 2 hours, 6 hours, 1 day, and 42 days, with subsequent visual and scanning electron microscopic examination of the prostheses completed. All tubes were free of thrombus deposits. Minimal junctional thrombi were found, probably due to differences in physicochemical characteristics of the vascular prostheses and recipient vessels. The results are compared with those in the control group (copper tubes with no current) and dc polarized copper tubes. While the control tubes occluded in 2 to 6 hours, the dc and ac polarized tubes remained patent. Of the ac and dc polarized tubes, the former tubes lasted up to 6 weeks with less thrombus deposit. The mechanism of operation of the ac polarized copper prosthesis is not fully understood.

Animals↗