Biomedical subjects

W Schraut

Publications and source records attributed to W Schraut.

33 records · Page 2Linked to original sources

PubMed1990

Inverse relationship of CA2+ mobilization and cell proliferation in CD8+ memory and virgin T cells.

Memory T cells can now be defined with various monoclonal antibodies but little is known about the functional properties of these cells as compared to virgin T cells. We have studied Ca2+ mobilization and proliferation of memory and virgin cells in both the CD4 and CD8 subsets in response to phytohemagglutin-in. Using two-color fluorescence (yellow, red) for cell surface staining combined with two-color fluorescence for the Ca2+ chelator indo-1 (violet, blue) we can demonstrate that CD8+UCHL1+ memory cells exhibit a 1,5-fold higher influx than the CD8+UCHL1- virgin cells. The same pattern was obtained when CD8 memory and virgin cells were defined by a reciprocal marker (Leu-18) indicating that the higher response of memory CD8 cells is independent of the monoclonal antibody used to identify the cells. For the respective CD4 subsets no such clear-cut pattern of Ca2+ influx was evident. Analysis of proliferation in both subsets indicates that CD8+UCHL1- cells strongly proliferate in response to PHA, while CD8+UCHL1+ memory cells show only a minimal response with the average cpm values being 6-fold lower. In some instances no proliferation at all was detectable in the CD8+UCHL1+ cells. Identification of the subsets by reciprocal markers confirmed the lower proliferative response in the CD8 memory cells. Hence, within the CD8 compartment the memory cells, after phytohemagglutinin stimulation, exhibit a high Ca2+ mobilization but a low to absent proliferation, while the converse is true for the naive cells. These data show that (a) Ca2+ mobilization and proliferation are inversely correlated and (b) an initially vigorous response of memory cells may be subject to negative control mechanisms.

Antigens, Differentiation↗

PubMed1983

Atraumatic perforation of bladder. Necessary differential in evaluation of acute condition of abdomen.

Perforation of the urinary bladder without history of antecedent trauma is a rare clinical occurrence. However, in patients with acute conditions of the abdomen, especially those with previous voiding symptoms, the diagnosis should be considered. Three cases are reported. Patients presented with an atraumatic bladder perforation and peritonitis secondary to chronic inflammation, bladder outlet obstruction, and transitional cell carcinoma. After review of the literature, a classification of atraumatic bladder perforation has been revised to include presently available reports of this entity.

Abdomen, Acute↗

PubMed1981

[Autologous vein transplants for digital revascularization after hand injuries].

In this study, reverse autogenous vein grafts were employed to bypass vascular defects in replantations and occluded arteries in hands with chronic post-traumatic ischemia. In 32 thumb replantations, vein grafts were used as short interposition segments or longer bypass grafts. The bypass grafts have the advantage of permitting proximal and distal anastomoses in undamaged tissue. In 5 post-traumatic chronically ischemic hands, vein grafts were employed to bypass arterial occlusions. All grafts remained open and cold intolerance improved as tactile discrimination returned. Simultaneous arterial and nerve reconstruction with grafts achieved favorable results in 2 patients. The measurement of digital blood pressure with the aid of a Doppler ultrasonic probe permitted preoperative evaluation of the degree of ischemia and postoperative confirmation of patency of the vein grafts.

Adult↗

PubMed1979

Ventricular fibrillation during cardiopulmonary bypass: long-term effects on myocardial morphology and function.

Mongrel dogs were subjected to hypothermic (28 degrees to 30 degrees C) cardiopulmonary bypass with hemodilution by 50%. In two groups of 8 dogs each, ventricular fibrillation was induced for 60 and 90 minutes, respectively, while the dogs were on bypass. A group of 6 dogs with the heart beating but nonworking served as control. Seven weeks after operation, hemodynamic measurements were made in the survivors (6 in each group) and the heart was fixed by perfusion with glutaraldehyde. Multiple transmural samples were taken from both ventricles. Light microscopy revealed solitary left ventricular scars (0.5 to 3 mm wide) in 2 hearts each from Groups 2 and 3. None of the hearts exhibited diffuse subendocardial fibrosis indicative of healed ischemic injury. All animals were hemodynamically normal. We conclude that in the nonhypertrophied heart, ventricular fibrillation up to 90 minutes with continuous bypass-sustained coronary perfusion (perfusion pressure at or above 70 mm Hg) offers protection from permanent myocardial injury.

Animals↗

PubMed1977

Does local cardiac hypothermia during cardiopulmonary bypass protect the myocardium from long-term morphological and functional injury?

Twenty-eight dogs were subjected to 90 minutes of hypothermic (30 degrees C) cardiopulmonary bypass with moderate hemodilution. In 6 dogs the heart was vented and beating for 60 minutes. Eight dogs underwent ventricular fibrillation with coronary perfusion (VF + CP). In 14 dogs the aorta was cross-clamped for 60 minutes while the myocardium was protected by local cardiac hypothermia (ICA + LCH). Eighteen animals survived. Hemodynamic studies at seven weeks revealed no major differences among the three groups. At postmortem examination, no gross scarring was noted in any heart. Microscopical examination of 14 hearts was completely-normal. In the VF + CP group, 2 hearts had isolated microscopical scars. Similar linear subendocardial scars (less than or equal to 1.5 X 0.5 mm) were noted in 2 hearts subjected to ICA + LCH. Survival after 60 minutes of VF + CP or ICA + LCH did not result in long-term morphological injury to or functional impairment of the myocardium.

Animals↗

PubMed1976

Permanent in-series cardiac assistance with the dynamic aortic patch: Blood-prosthesis interaction in long-term canine experiments.

The blood-prosthesis interaction of the dynamic aortic patch (DAP), an in-series assist device for permanent circulatory support which is implanted in the descending thoracic aorta, was studied in 65 long-term experiments. Periods of postoperative observation with the device inactive or activated ranged from 2 weeks to 22 months. The intravascular surface of the DAP, fabricated of Dacron velour backed by bioelectric polyurethane, displayed various degrees of organization, ranging from a thin fibrin layer to a well organized pseudointima. Activation of the system did not prevent the development of an organized pseudointima. Changes in free-plasma hemoglobin were minimal; platelet count per square millimeter and state of reactivity remained within normal limits. Evidence of renal embolization, attributable to activation of the device, was found in five animals. Frequent lethal complications were aortic rupture and infections of the thoracic cavity originating at the implantation site. Further improvement of the DAP and the techniques of implantation is indicated to insure its efficacy during long-term implantation and activation.

Animals↗

PubMed1974