Investigation of (Ca2+ + Mg2+)-ATPase phosphoprotein formation in erythrocyte membranes of patients with cystic fibrosis

The (Ca2+ + Mg2+)-ATPase present per mg of protein in erythrocyte membranes of controls and patients with cystic fibrosis (CF) was determined by estimation of the levels of its phosphoprotein. In the presence of 10 mM free Ca2+, which inhibits phosphoprotein decomposition, significantly less phosphoprotein intermediate, ECaP, was found in erythrocyte membranes from CF patients than in age- and sex-matched controls; this correlated with a significant decrease in (Ca2+ + Mg2+)-ATPase activity. These observations indicate a decrease in the number of functional (Ca2+ + Mg2+)-ATPase molecules in erythrocyte membranes from CF patients or an alteration in either the structure of the pump protein or the composition of its environment.

Na-K-C1 cotransport and Na pump in red cells of young blacks and blood pressure response to salt loading

The functional operation of Na and K fluxes, mediated by the furosemide-sensitive (FS) Na-K-C1 cotransport and the ouabain-sensitive Na pump, was studied in a representative young (18-22 years) black population. Cation fluxes (mumol/L cell X hour = FU) were studied prior to salt loading; results were compared with the blood pressure response to chronic oral salt loading. All subjects (n = 26) took 10 g/day NaC1 plus their usual diets for 14 days. A mean arterial blood pressure increase higher than 5 mmHg was considered a sodium-sensitive (SS) response; a response lower than 5 mmHg was considered sodium-insensitive (SI). The Km for Nac to stimulate FS Na efflux was significantly greater in SS (SS = 13.8 +/- 1.39 mmol/L cells, n = 15; SI = 8.5 +/- 0.8 mmol/L cells, n = 11; p less than 0.001). Inward cotransport of Na and K was also studied at constant Nac (13 mmol/L cells) and incubation of 140 mM Na and 4 mM K. No significant differences were found in the Vmax of outward FS Na and K efflux, FS86 Rb, Na influx, net Na movement (efflux minus influx), and the Na/K ratio of inward cotransport. Several parameters of the ouabain-sensitive Na pump (Vmax of the Na efflux, Rb influx, Na/K coupling ratio (2.2), and fresh Nac) were found to be similar in both groups. The results indicate that in young blacks, the Na sensitivity of the blood pressure may be associated with lower affinity for internal Na of the outward Na-K-C1 cotransport system.

Fluorometric determination of nanogram quantities of protein in small samples: application to calcium-transport adenosine triphosphatase

A fluorometric micro protein assay based on fluorescamine-labelling of homogeneous proteins in solution has been developed which is capable of accurately quantitating as little as 25 ng protein at a concentration of 1.25 micrograms/ml. This micro assay uses a flow-through HPLC fluorescence detector. Typical micro assays measuring bovine serum albumin standards (0-25 mg/l) yielded linear regression coefficients of r = 0.999. Assays of purified Ca2+-ATPase solutions determined by the micro fluorescamine procedure correlated well with measurements made using the deoxycholate-TCA-precipitation modification of the Lowry assay: 1.0 microgram ATPase by Lowry method = 1.1 microgram protein by fluorescamine microassay (when both procedures were standardized with bovine serum albumin) (r = 0.995). The assay proposed offers a 100-fold increase in sensitivity, compared to the Lowry procedure.

Methylmethacrylate upper ureteral obstruction

A case of upper ureteral obstruction caused by methylmethacrylate cement after fixation of an L2-L3 vertebral fracture is reported. The probable mechanism, radiographic findings, and management of this complication are reviewed.

Thyroidectomy of SHR: effects on ventricular relaxation and on SR calcium uptake activity

Ventricular hypertrophy and hypothyroidism are each characterized by impaired cardiac muscle relaxation and sarcoplasmic reticulum (SR) calcium uptake activity. A previous report also showed that hypothyroidism does not reverse ventricular hypertrophy (left-to-right ventricular weight ratios) of spontaneously hypertensive rats (SHR). We characterized the effects of thyroidectomy of 8 wk duration on relaxation of ejecting hearts and on SR calcium uptake activity from SHR and nonhypertrophic Wistar-Kyoto rat (WKY) controls. Relaxation was quantified by plotting maximum left ventricular pulse pressure (Pmax) vs. the area under the falling phase of the left ventricular pressure wave at three different pressure loads. Ventricles of euthyroid SHR were characterized by impaired relaxation and depressed SR calcium uptake activity compared with those of euthyroid WKY, confirming earlier studies. Thyroidectomy reduced ventricular relaxation and SR calcium uptake activities to about the same extent in SHR and WKY strains so that these measurements were most depressed in the SHR hypothyroid group. When all groups were considered, the extent of mechanical relaxation ex vivo and the rate of SR calcium uptake in vitro were well correlated.

Isolation and characterization of erythrocyte membrane Ca2+-ATPase in cystic fibrosis

Ca2+-ATPase was purified from erythrocyte membranes prepared from cystic fibrosis (CF) blood samples (n = 10) and from age/sex-matched control blood samples (n = 10). The kinetics of calcium activation of the purified enzyme was investigated in the presence of asolectin phospholipids and found to be virtually identical for both CF and control preparations: VCa2+ = 3.01 +/- 0.24 mumol ATP hydrolyzed/mg pure enzyme/min (mean +/- SE) and 3.09 +/- 0.20 for CF and control Ca2+-ATPase, respectively; KCa2+ = 0.328 +/- 0.046 mu molar free calcium and 0.333 +/- 0.040 for CF and control enzyme, respectively. The preparative procedure used (one-step purification by calmodulin-affinity chromatography) allowed quantitative recovery of essentially 100% of the Ca2+-ATPase present in detergent-solubilized erythrocyte membranes, enabling expression of the yield of purified enzyme in terms of the quantity of starting membrane protein: 0.127% +/- 0.006% (w/w) and 0.140% +/- 0.007% for CF and control enzyme preparations, respectively. None of the parameters evaluated showed a statistically significant difference (p less than 0.05) between the CF and control groups. Furthermore, when CF and control purified Ca2+-ATPase samples were analyzed by high-resolution gradient SDS-polyacrylamide gel electrophoresis, no differences in mobility were observed (mol wt = 128 kdaltons). Thus, Ca2+-ATPase purified from CF erythrocyte membranes and assayed in the presence of asolectin appears to be quantitatively similar to control purified enzyme in amount, molecular weight, and kinetics of activation by calcium. These data suggest that Ca2+-ATPase may not be the defective gene product in CF.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of a soft catheter for acute peritoneal dialysis in infants and children

Acute peritoneal dialysis in 49 infants and children is described comparing the use of the conventional hard Trocath catheter and the soft catheter. The mean age of the patients was 3.6 years (range 1 day--17 years). Sixteen were treated using the hard Trocath catheter and 33 were treated using a soft catheter. Overall mortality for the total patient population was 43%. Twenty-three neonates were included in the series with an overall mortality of 61%. Significantly less mortality was observed in the 26 patients older than two months of age (31%). Major complications of the dialysis procedure included viscus perforation in three neonatal patients and subcutaneous extravasation of dialysate in two older patients. These major complications occurred only with the use of the Trocath. Two episodes of peritonitis occurred in two adolescent patients and were associated with an interruption of the sterile system. Peritonitis was not specifically related to the type of catheter used. We conclude that major complications associated with the use of the hard catheter for peritoneal dialysis in neonates precludes its continued use in this population. The alternative use of a soft catheter is recommended in neonates. Elective use of a soft catheter for acute peritoneal dialysis in older patients would also seem to be indicated.

Congenital aplasia of the deep veins of lower extremities in children: the role of ascending functional phlebography

Eighty-two children with vascular diseases underwent phlebography. Congenital aplasia of the deep venous system of the lower extremities was diagnosed in 10 children. With ascending functional phlebography, three anatomic variations with different degrees of venous dysfunction were defined: aplasia of the femoral vein with collateral drainage into the common femoral vein, aplasia of the femoral vein with drainage into the internal iliac vein, and total aplasia with drainage into the axillary vein. The phlebographic findings correlated with the symptoms. Patients with type a aplasia had no clinical and radiologic signs of venous insufficiency. Patients with types b and c aplasia had severe venous insufficiency that necessitated supportive treatment. Palliative surgical procedures such as hemorrhoidectomy, clitoridectomy, and excision of bleeding vascular nevi were performed. Ligation or excision of the dilated superficial veins (usually the main channels for venous drainage from the extremity) is absolutely contraindicated. Ascending functional phlebography is therefore essential for correct diagnosis and planning of future therapy.

Treatment of colorectal hepatic metastases by intrahepatic chemotherapy alone or as an adjuvant to complete or partial removal of metastatic disease

Because of the wide variation in reported benefits from the use of intrahepatic chemotherapy for colorectal hepatic metastases, the authors performed their own phase II studies comparing the use of intrahepatic chemotherapy alone and intrahepatic chemotherapy as an adjuvant to complete or partial removal of metastatic colorectal cancer to the liver. Techniques for partial removal included unilateral and bilateral wedge resection, peripheral presinusoidal embolization of the liver, and portal vein branch ligation. Patients were staged using the per cent hepatic replacement method of Pettavel and Taylor, and patients with bilateral metastases were included in the study. Twenty-seven patients, mean age 60.3 years, were examined. There were 19 males, mean age 60.4 years, and eight females, mean age 60 years. The patients were divided into four groups. Group A had an implantable pump only; Group B had an implantable pump and resection; Group C had an implantable pump and arterial embolization and portal vein branch ligation; and Group D had an implantable pump, partial resection, arterial embolization, and portal vein branch ligation. Kaplan-Meyer survival curves were calculated for all of these groups. A separate analysis was carried out for each of the stages, and a comparison was made. The study indicated that the overall median survival time was 18 months and that the more radical the treatment in addition to chemotherapy, the better the results. Such results were not totally dependent on the staging of the tumor volume but were dependent on the degree of extirpation of the tumor. In Group C, consisting primarily of Stage IIa, IIIa, and IV patients (i.e., unresectable patients), a doubling of expected median survival to 12 months could be achieved, compared to those in Group A, which achieved a median survival of only 6 months.

Semipermeable occlusive dressings. Effects on growth of pathogenic bacteria and reepithelialization of superficial wounds

Six commercially available semiocclusive dressings were tested for their effect on the growth of resident and pathogenic bacteria and the reepithelialization of experimentally induced wounds in human volunteers. Scarification and abrasion-type wounds inoculated with Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa were quantitatively cultured at different times after being covered with the dressings. Reepithelialization was assessed by serial stereomicrographs. None of the dressings was able to prevent clinical infection. All dressings provided microenvironments that were conducive to the growth of resident and pathogenic bacteria. There was no difference in the rates of reepithelialization.

A comprehensive theoretical model of psychological reaction to loss

This article describes a multidimensional model which may be applicable to study three types of loss, interpersonal loss, loss of a limb or function, and environmental loss or loss of peace of mind. It is a preliminary attempt to collate relevant variables associated with the three types of loss into one comprehensive model which assumes that the dynamic processes associated with and encountered in one area of loss can be extrapolated for use in comprehending other areas of loss. A number of testable hypotheses can be derived for future validation and research.

Free perforation in Crohn's disease: a report of 33 cases and review of literature

Thirty-three patients with free perforation in Crohn's disease are described. There are 14 males and 19 females in this series with ages ranging from 14 to 79 years. The sites of perforation were 22 of the ileum, nine colonic, one jejunal, and one gastroduodenal. Toxic megacolon coexisted in two. Reperforation occurred in three. Free perforation was the presenting sign of the disease in three. Steroid therapy coexisted in 16 patients but in five was administered for less than 10 days before perforation. Obstruction coexisted in only three patients. There were two deaths. Twenty-two patients were treated with resection and diversion, nine patients with resection and drainage, and two with plication only. No relationship between steroid therapy, duration of disease, toxic dilatation, or obstruction with perforation could be established. Resection of the perforated disease segment is necessary when possible. In contradistinction to previous literature, free perforation in Crohn's disease is not as unusual as heretofore believed.

The rising popularity of cocaine: how serious a problem?

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Two-dimensional echocardiographic monitoring during percutaneous endomyocardial biopsy

The use of two-dimensional echocardiography in four successive views was assessed to determine the optimal view for localizing a transvenous percutaneous bioptome in 23 consecutive patients undergoing right ventricular endomyocardial biopsy. The biopsy catheter tip was viewed in 21 (91%) of the 23 patients. The apical four chamber view allowed visualization of the bioptome head in 19 patients (83%), the subcostal view in 8 (34%) and the long-axis view in 4 (17%). The parasternal short-axis view was not helpful in any patient. Biplane fluoroscopy was not reliable in localizing the bioptome head against the interventricular septum and did not identify inadvertent septal perforation in one patient. Echocardiography also can be used to immediately identify possible complications.

Bacterial clearance in the intact and regenerating liver

The Kupffer cells in the liver play an important role in reticuloendothelial system (RES) function by clearing particulate matter and bacteria from the blood stream. While hepatocyte regeneration and function have been extensively studied following partial hepatectomy, little information is available concerning RES function in the regenerating liver. This study investigates hepatic RES function by evaluating bacterial clearance (live E. coli) in the intact and regenerating liver. Thirty-four young male Sprague Dawley rats were studied. Twenty-two animals underwent a standard 70% partial hepatectomy using ligature technique and 12 had a sham operation. Both groups of rats received 10(9) organism of S35 labeled E coli, intravenously at 24 hours, 72 hours, 2 1/2 weeks, and 6 weeks postoperatively. Rats were killed 10 minutes following injection and liver, lung, spleen, and kidney harvested, fixed, and radioactivity was determined using a scintillation spectrometer interfaced with a micro-computer counting the S35 radiolabel. The total organ count of trapped bacteria in liver in partially hepatectomized rats was lower than intact controls at 24 hours (22.0% v 46.4%, P less than .01), but was similar at 72 hours, 2 1/2 weeks, and 6 weeks. Partial hepatectomy increased the amount of bacterial trapping in the lung at 24 hours (11.3% v 1.7%, P less than .01) and 72 hours (10.1% v 1.7%, P less than .05) and returned to normal at 2 1/2 weeks and 6 weeks. Splenic activity was increased following hepatectomy at 2 1/2 weeks. Renal clearance was increased at 72 hours and 2 1/2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of trypsin stimulation of cardiac adenylate cyclase

The activity of adenylate cyclase present in a purified dog heart sarcolemmal preparation in the presence of magnesium as cosubstrate is biphasically influenced by increasing concentrations of trypsin: Stimulation at low concentrations (0.5 to 1 microgram/mL) is followed by inhibition at higher concentrations. In the presence of manganese in place of magnesium, the stimulation phase is abolished but the inhibition is still observed at the same trypsin concentrations. The trypsin stimulatory effect does not occur when trypsin is preincubated with cardiac membranes prior to the addition of ATP. When trypsin is added with ATP, the stimulation is expressed by an increase in the Maximal Velocity (Vmax) rather than a decrease in the Michaelis constant (Km). The stimulatory effect of trypsin on AC activity is rapid, linear and irreversible. GTP, Gpp(NH)p and adrenaline stimulatory curves are shifted to the left in the presence of trypsin. These results suggest that protease stimulation of cardiac AC involves the GTP-binding protein (N) activity, but the exact mechanism remains to be determined.