Biomedical subjects
Publications and source records attributed to W T Chen.
Six maintenance hemodialysis patients are described in whom ascites was encountered at a time when they were anephric. No etiology for ascites could be found, and it was presumed that these patients were manifesting so-called "hemodialysis ascites". Our findings suggest that the use of bilateral nephrectomy in the treatment of hemodialysis ascites should be re-evaluated.
The effect of negative-pressure isolated ultrafiltration on leucocytes, platelets, and clotting factors was evaluated in maintenance hemodialysis patients. A significant decrease in the number of leucocytes was observed during the first 45 minutes of ultrafiltration. However, by one hour, leucocyte counts had returned to pre-ultrafiltration values. A slight, of haptoglobin, free hemoglobin, or fibrinogen after one hour of isolated ultrafiltration. Levels of fibrin degradation products and fibrin monomers similarly showed no change. Heparin administration alone had no effect on the above hematologic values. We suggest that isolated ultrafiltration, as clinically practised, has little acute effect on the coagulation system, and does not cause detectable hemolysis. The transient decrease in leucocyte count, and the modest fall in platelet count that were found are in keeping with changes previously reported to occur during hemodialysis.
Ten alert, non-uraemic, splenectomised dogs were subjected to isolated ultrafiltration until mean arterial pressure decreased to less than 80mmHg. On a separate occasion, in the same dogs, ultrafiltration was performed in the course of haemodialysis. Whether or not dialysate was circulated, ultrafiltration resulted in marked increases in total peripheral vascular resistance, and large increases in plasma concentrations of vasoactive hormones, including norepinephrine. Our results suggest that, in the non-uraemic dog, the haemodynamic responses to ultrafiltration during dialysis and to isolated ultrafiltration are similar.
Fibronectin is an extracellular matrix protein that has been implicated in the spreading and adhesion of cultured fibroblasts to their substrata. In this paper, double immunoelectron microscopic labeling experiments for fibronectin and for concanavalin A-binding proteins on the cell surface were carried out on ultrathin frozen sections of cultures of embryonic chicken heart fibroblasts. On cross sections though the focal adhesions of the cell to the substratum there was substantial labeling for concanavalin A-binding proteins but no detectable labeling for fibronectin, whereas both the binding proteins and fibronectin were extensively labeled elsewhere on the cell surface and substratum. These results demonstrate that fibronectin is not present within the sites of focal adhesions. Therefore, the functions of fibronectin in cell spreading and adhesion are not directly mediated through its binding at focal adhesion sites. An alternative model is presented which can account for such fibronectin functions.
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Twelve patients underwent hemodialysis using dialysate containing 130 mEq/L sodium, and, on a separate occasion, dialysis using a dialysate of constantly decreasing sodium concentration (from 150 to 133 mEq/L). Hydrostatic ultra-filtration during dialysis was performed at a constant rate (900 ml/hr) during both treatments, and was continued until a substantial drop in mean arterial pressure (-15%) or symptoms were observed. A double-blind comparison of the two treatment modalities was thus achieved. At the end of ultrafiltration, significantly more fluid had been removed using decreasing sodium dialysate (2.9 +/- 0.3 kg) than when using the low-sodium dialysate (1.9 +/- 0.2 kg, P<0.001). Plasma sodium concentration at the end of ultrafiltration using decreasing sodium dialysate was not significantly different from the predialysis level. Hydrostatic ultrafiltration using a dialysate of decreasing sodium level may prove to be a useful means of removing excess fluid asymptomatically from dialysis patients.
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Previous measurements of fluid absorption from the peritoneal cavity were made after a single injection of a protein-bound marker by following changes in the concentration of the marker with time. Absorption of the marker substance itself had to be estimated. The present study measured absorption of peritoneal fluid by more direct methods. 1.5 to 2.1 L of 0.9% saline, along with 10 muCi of RISA were infused into the abdomens of nine chronic renal failure patients through peritoneal dialysis catheters. Initial paritoneal fluid volumes were determined by dilution. After 7 hr, a second dose of RISA (5 muCi) was infused, and volumes in the peritoneal cavity were again determinted by dilution of the increment dose. At 8 hr, an attempt was made to recover the RISA remaining in the peritoneal cavity by draining and repeatedly flushing that space. The amount of RISA recovered was used to calculate independently the amounts of RISA and fluid which had been absorbed during the 8 hr period. There was good agreement between peritoneal fluid volumes calculated at 7 and 8 hr by these and other techniques. By 7 hr, 23.8% +/- 10.9 S.D. of the initial peritoneal fluid volume ahd been absorbed. The amount of RISA absorbed during the same period was 17.3% +/- 4.9 of the initially administered dose. At 7 hr, only 23.7% +/- 6.3 of the absorbed RISA was in the plasma. The proposed techniques of volume measurement are valid and point to great variation among patients in the rate of fluid absorption from the peritoneal cavity.
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This paper describes the phenomenon of retraction-induced spreading of embryonic chick heart fibroblasts moving in culture. Measurable criteria of cell spreading (increase in area of the spreading lamella, and total spread area of the cell) are found to change predictably with retraction of a portion of the cell margin. Ruffling activity was found to increase. The leading lamella of a spread fibroblast ordinarily advances slowly, with an average area increase of approximately 21 mu2m/min. A 10- to 30-fold increase in spreading occurs within 8 s after onset of retraction at the trailing edge and then decreases slightly so that by 1 min the increase in spreading is five to tenfold. During this period, there is a linear relationship between area increase at the leading edge and area decrease at the trailing edge. During the next 10--15 min, spreading gradually decreases to normal. Although the relationship between area spreading and area retracting of fibroblasts at different phases of movement is not significantly linear, it is highly correlated (Table II). These results suggest that the rate of fibroblast spreading may be inversely related to the degree of spreading of the cell as a whole.
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Previous studies using bioassay demonstrated the presence of a vasoactive substance or substances in coronary sinus blood during myocardial reactive hyperemia which had, on bioassay, characteristics of adenosine and/or AMP. In the present studies, specific blockers were applied to an improved bioassay system to define more precisely the nature of the substance or substances and to determine whether it also appears during local cardiac hypoxia. In the anesthetized dog, coronary sinus blood was bioassayed in an isolated autologous kidney during reactive and hypoxic dilation. During reactive dilation, the bioassay kidney responded with a large resistance increase which was blocked by theophylline and adenosine deaminase and converted to a decrease by adenosine autoblockade. The same was true for hypoxic dilation, except in this instance, only adenosine deaminase reduced the response (40%). Theophylline and adenosine autoblockade eliminated responses of the bioassay organ to both exogenous adenosine and exogenous AMP, but adenosine deaminase was specific for adenosine. These results confirm that one or more vasoactive substances appear in sinus blood in vasoactive quantities during cardiac reactive dilation, and that the peak concentration correlates roughly with the peak flow. In addition, they show that this also is the case for hypoxic dilation. More importantly, they demonstrate that the substance almost certainly is adenosine in the case of reactive dilation, and that increased adenosine levels also are present during hypoxic dilation, but in addition, suggest that AMP sometimes appears in coronary sinus blood during severe cardiac hypoxia in the dog heart.
Olecranon bursitis with effusion in four maintenance hemodialysis patients was successfully treated with simple aspiration.
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Peritoneal dialysis using a chloride-rich dialysate succeeded in correcting systemic metabolic alkalosis in a patient with renal failure. The present approach may have a place in the therapy of metabolic alkalosis.