An approach to optimal dialysis using urea kinetic modeling.

Urea kinetic modeling (UKM) was carried out to evaluate the water control in patients undergoing long-term hemodialysis. In 21 patients on chronic dialysis, the results of two different determinations of the total body water, i.e. by the deuterium oxide (D2O) method and by UKM, were compared. A correlation was observed with Y = 0.98X + 5.9 (P less than 0.01, r = 0.91) for males and Y = 0.97X + 6.2 (P less than 0.01, r = 0.90) for females, indicating that UKM is useful for determining the total body water. In addition, the 21 patients were classified into two groups based on their ECG findings, and UKM was performed in the two groups for comparison. The values of the total body water were 68.5 +/- 4.0% and 68.6 +/- 6.2% of body weight, respectively, with no significant difference between them. However, the CTR was 50.2 +/- 2.8% and 46.2 +/- 4.4%, respectively. Thus, not only X-ray examinations but also UKM should be carried out to determine the standard weight (SW-DW) in the presence of cardiac dysfunction. Instructions for water control were given when the total body water exceeded 73% during the UKM measurements over 5 years, which allowed an optimal total body water to be maintained thereafter. The possible influence of erythropoietin (EPO) was also examined by performing UKM in 8 cases receiving EPO and 7 cases without EPO. No noticeable difference was observed between the two groups. 17 patients using a polyacrylonitrile (PAN) membrane were further divided into those with and those without EPO to evaluate the possible influence of the PAN membrane-EPO combination. As a result, no significant difference was demonstrated, suggesting that UKM can be satisfactorily performed under such conditions. In 11 patients on chronic dialysis, the levels of alpha-human atrial natriuretic peptide (alpha-hANP) were measured pre- and post-dialysis to examine the relationship between the change in alpha-hANP and rate of weight loss (%). A significant correlation was observed with Y = 12.8X + 5.1 (P less than 0.05, r = 0.68). In conclusion, UKM was found to be useful for evaluating the water control and for assessing the optimal dialysis in patients receiving long-term hemodialysis.

[Activation of complement by hemodialysis membrane].

Incubation of normal human serum with hemodialysis membranes in vitro resulted in conversion of C3 which was detected by crossed immunoelectrophoresis. In addition, formation of C3d was also observed, as was detected by double-decker rocket immunoelectrophoresis. Furthermore, breakdown products of complement (iC3b, C4d & Bb) in plasma samples were measured by ELISA. The microassay plates were coated with monoclonal antibodies which bind specifically to human iC3b, C4d and Bb, respectively, while the plasma samples were drawn from five polycystic kidney patients during initial hemodialysis. As a result, the iC3b and Bb levels in plasma were seen to increase during hemodialysis but the C4d levels revealed no significant changes. It was also observed that the Bb levels in patients undergoing hemodialysis were significantly higher than those in various renal and collagen diseases. Terminal complement complex (TCC) was not present in detectable amounts in normal human serum when measured by ELISA. However, incubation of normal human serum with hemodialysis membranes in vitro resulted in detection of TCC. TCC was present in the same plasma samples drawned from the five polycystic kidney patients during initial hemodialysis. It is suggestive that activation of complement by hemodialysis membrane is predominantly mediated through the alternative pathway and products such as TCC and anaphylatoxin are formed by this activation.

[Limitation of myocardial infarct size by polyethylene glycol-conjugated superoxide dismutase in a canine model of 90 min coronary occlusion followed by 4 days of reperfusion].

The role of oxygen free radicals in the genesis of myocardial reperfusion injury is supported by the studies with superoxide dismutase (SOD) which provides protection against the extention of myocardial injury. However, the efficacy of SOD may be of limited value due to its short plasma half-life of 5-6 min. Conjugation of SOD to polyethylene glycol (PEG-SOD) increases the half-life to greater than 30 hours. Forty-two male, mongrel anesthetized dogs were subjected to occlusion of left circumflex coronary artery for 90 min followed by 4 days of reperfusion. Dogs were randomized to receive either PEG-SOD (1,000 U/kg) or PEG-Albumin via left atrium, starting 15 min before reperfusion and ending simultaneously with reperfusion, and were sacrificed 4 days later. The hearts were stained by ex vivo dual perfusion technique for the determination of myocardial infarct size. Infarct size expressed as a percent of area-at-risk in PEG-SOD (n = 13) and PEG-Albumin (n = 13) treated dogs differed significantly between groups: 29.2 +/- 1.6% vs 44.2 +/- 2.6%, respectively (p less than 0.01) with no observed difference in the size of area-at-risk: 46.0 +/- 1.6% vs 44.4 +/- 1.4% (n.s.). Hemodynamic parameters between groups did not differ during coronary artery occlusion and could not account for the effect of PEG-SOD on infarct size. Collateral blood flows to the inner 2/3 of the ischemic myocardium for both groups did not differ. Plasma SOD activity in PEG-SOD group initially exceeded 20 U/kg and sustained significantly for 4 days.(ABSTRACT TRUNCATED AT 250 WORDS)

[Study of hard mineralized tissues effect of calcium-deficient diets with and without cholecalciferol supplementation on the incisor dentine of rats].

It has been known that both tooth and bone have an apatite structure similar to that of mineral hydroxyapatite. The apatite crystal in living tissues of tooth and bone generally is constructed from submicrocrystals and has many impurities. It seems that chemical and physical aspects of resistance of hard tissues depend on the diet. Consequently, the matrix of organic, free radicals in X-ray irradiated hard tissues were studied by means of electron spin resonance (ESR). The effects of calcium-deficient diets with and without cholecalciferol supplementation on the incisor dentine of rats were examined by the rate of decay of organic, free fadicals in X-ray irradiated incisor dentine of rats. The crystal size of incisor dentine became smaller in case of calcium contained diet.

A neurokinin-1 receptor antagonist reduced hypersalivation and gastric contractility related to emesis in dogs.

The roles of tachykinin neurokinin-1 (NK1) receptors in the induction of fictive retching, hypersalivation, and gastric responses associated with emesis induced by abdominal vagal stimulation were studied in paralyzed, decerebrated dogs. Vagal stimulation induced gradual increases in salivary secretion and activity of the parasympathetic postganglionic fibers to the submandibular gland, relaxation of the gastric corpus and antrum, and fictive retching. However, hypersalivation and increased nerve activity were suppressed and antral contractility was enhanced during fictive retching. An NK1 receptor antagonist, GR-205171, abolished the enhancement of antral contractility and fictive retching but had no effect on corpus and antral relaxation. Hypersalivation and increased nerve activity were inhibited by GR-205171 but were not completely abolished. Reflex salivation by lingual nerve stimulation was unaffected. These results suggest that GR-205171 acts on the afferent pathway in the bulb and diminishes hypersalivation and antral contraction related to emesis as well as fictive retching but does not affect gastric relaxation or hypersalivation induced by the vagovagal, vagosalivary, and linguosalivary reflexes.

Maxillary growth after two-stage palatal closure in complete (unilateral and bilateral) clefts of the lip and palate from infancy until 10 years of age.

The purpose of the study is to clarify the maxillary growth effects following different types of palatal closure in complete clefts of the lip and palate from infancy to 10 years of age. Lip repair, carried out at 5 months in one stage, was accomplished by Tennison's procedure. These patients were then assigned randomly to each of the 4 experimental groups according to the types of clefts and of palatal closure. One group of 14 patients in unilateral cases (Unil-S) and another group of 8 patients in bilateral cases (Bil-S) received mucoperiosteal palatal push-back procedure in a single stage at 20 months. The third group of 16 patients in unilateral cases (Unil-T) and the fourth group of 7 patients in bilateral cases (Bil-T) received the two-stage palatal closure based on Perko technique in which primary veloplasty was accomplished at 20 months and hard palate closure at 5 year 10 months. Non-cleft subjects were served as Controls. A longitudinal maxillary growth was monitored by the measurements of maxillofacial cast models obtained from each of the subjects. The results showed that the growth in depth and height of the maxilla of the Unil-T showed catch-up growth after primary veloplasty and resulted in no significant differences compared to that of the Control in the later phases, however, the Unil-S did not. The maxillary growth inhibition in height was characteristic in both Bil-S and Bil-T after palatal closure. There were no differences between the Bil-S and Bil-T in any dimensions and observation phases. The results indicate that the employment of the two-stage palatal closure is more beneficial for the unilateral cases, however, careful consideration is needed in bilateral cases.