Ultrasonic studies on polystyrene/styrene butadiene rubber polymer blends filled with glass fiber and talc.

The compatibility of solid blends: PS/SBR, PS/SBR filled with glass fiber and PS/SBR filled with talc were studied using ultrasonic pulse echo technique. Measurements were carried out at room temperature (298 K) and a frequency of 3 MHz. The ultrasonic velocity for the compressional wave and that for shear wave have been measured to obtain the elastic moduli data by knowing of density. The variation of ultrasonic wave velocities and elastic moduli with weight percent of the blend was found to be linear in PS/SBR blend, indicating some degree of compatibility but the drawback of elastic moduli indicate incompatibility of the system blend, while it deviates from linearity in blends of PS/SBR filled with glass fiber and talc but the increase in elastic moduli indicates that there is an increase in degree of compatibility between PS and SBR due to adding of glass fiber or talc. The ultrasonic absorptions for longitudinal wave in the temperature range from 298 to 423 K in the studied system were measured using ultrasonic pulse echo technique. Typical results showing the temperature dependence of the ultrasonic absorption at frequencies of 1, 2, 3 and 5 MHz are illustrated for all samples of the different compositions. The study of compositional and temperature dependence of the ultrasonic absorption in the present studied blends reveals the same behavior of the compatibility degree of the blends. Density data of the blends confirmed the ultrasonic results. Also the correlation between hardness and elastic moduli for the present blend systems has been studied.

Severity of illness scores and the outcome of acute tubular necrosis.

The outcome of patients with acute renal failure (ARF) due to acute tubular necrosis (ATN) was evaluated in this study. Two hundred and twenty-two patients with a mean age of 55.1+/-17.7 years (range 19-97 years; male 153, female 69) who developed ATN in the period from July 1991 through January 1997 were studied. Patients were divided into four groups according to their APACHE II scores at the time of the diagnosis of ATN. Group I included patients with an APACHE II score of 14 or less (n = 70), Group II with a score of 15-18 (n = 52), Group III with a score of 19-23 (n = 58), and group IV with a score of 24 or above (n = 42). The mean APACHE II score for each of the four study groups was 11+/-0.4, 16+/-0.2, 20+/-0.2, and 29+/-0.7, respectively. Patient survival was evaluated by the Kaplan-Meier analysis with censorship at 12 months. Survival rates at 180 days were 67%, 47%, 39%, and zero%, for group I through IV respectively, chi2 = 27.99, p < 0.0001, with a median survival of >365, 120, 31, and 11 days, for groups I through IV, respectively. For patients with oliguria (n = 88) survival at 180 days was 23% vs. 58% for patients without oliguria (n = 134), p < 0.0001, median survival 13 vs. 364 d. Six months survival of those who required dialysis (n = 79) was 25% vs. 58% for those whom dialysis was not needed (n = 143), p = 0.001, median survival 15 vs. 364 d, respectively. In patients with sepsis (n = 58), 6 months survival was 35% vs. 50% for those without sepsis (n = 164), p = 0.013, median survival 14 vs. 169 d. In patients who required mechanical ventilation (n = 72), 6 months survival was 17% vs. 62% for those who did not need respiratory support (n = 150), p = 0.0001, median survival 13 vs. > 365 d, respectively. Finally, 6 months survival in patients with one (kidney only), two, three, and four organ failure was 76, 30, 11, and zero percent, respectively, p = 0.0001, median survival >365, 16, 11, and 12 days, respectively. We conclude that the use of the APACHE II score for the stratification of the severity of illness could be of clinical utility in predicting mortality in patients with ATN. Other predictors of poor prognosis include the need for dialysis, the presence of oliguria, the need for mechanical ventilation, the presence of sepsis, and the number of failed organs.

Peritoneoscopic versus surgical placement of peritoneal dialysis catheters: a prospective randomized study on outcome.

The most commonly used technique for insertion of peritoneal dialysis (PD) catheters is open surgical approach by minilaparotomy. Percutaneous implantation via the peritoneoscopic technique is expanding. Studies have suggested that PD catheters placed peritoneoscopically have longer survival rate than surgically placed ones. However, these studies were not randomized, where the surgical group had more patients who were obese or had prior abdominal surgery, and therefore, the selection of patients may have biased the results. We conducted a prospective randomized study in which patients underwent PD catheter placement by either the surgical or the peritoneoscopic technique. In the period from October 1992 through October 1995, 148 double-cuff, curled-end, swan-neck PD catheters were placed in 148 patients. The outcome of the 76 patients in whom the PD catheters were placed peritoneoscopically was compared with that of the 72 patients in whom the catheters were placed surgically. Early peritonitis episodes (within 2 weeks of catheter placement) occurred in 9 of 72 patients (12.5%) in the surgical group, versus 2 of 76 patients (2.6%) in the peritoneoscopy group (P = 0.02). This higher rate of infection was most likely related to a higher exit site leak in the surgical group (11.1%) as compared with the peritoneoscopy group (1.3%). Moreover, peritoneoscopically placed catheters were found to have better survival (77.5% at 12 months, 63% at 24 months, and 51.3% at 36 months) than those placed surgically (62.5% at 12 months, 41.5% at 24 months, and 36% at 36 months) with P = 0.02, 0.01, and 0.04, respectively. We conclude that peritoneoscopically placed PD catheters have a longer survival rate than surgically placed ones. Furthermore, the rate of exit site leak and early infection is lower in the peritoneoscopic method.

Peritoneal dialysis-associated peritonitis caused by Alcaligenes xylosoxidans.

Despite significant progress to decrease its incidence, peritonitis remains the main source of morbidity and treatment failure in patients on continuous ambulatory peritoneal dialysis (CAPD). The majority of cases of peritonitis result from infection with aerobic gram-positive (Staphylococcus epidermidis and Staphylococcus aureus), or gram-negative organisms. Less common organisms that are also reported include anaerobic bacteria, fungi, and mycobacteria, which collectively account for less than 10% of isolates cultured. We report a case of peritoneal dialysis-associated peritonitis, and review the literature on peritonitis caused by Alcaligenes species. Alcaligenes xylosoxidans is a nonfermenting gram-negative rod and opportunistic pathogen that is motile with peritrichous flagella. The clinical features and microbiological data of our case, as well as the other previously reported cases of peritonitis caused by Alcaligenes species show no particular pattern of peritoneal dialysate cell count. However, the rate of recurrence of peritonitis is characteristically high. The cause of such a high rate of recurrence of peritonitis is probably a reflection of the predilection of Alcaligenes species to cause infection in the 'sicker' patients, and the almost universal resistance of this species to most antimicrobial agents. We, therefore, recommend that catheter removal be undertaken as early as the identification of the organism is made. Whether patients should be allowed to return to CAPD after recovery is a more difficult question. We suggest that a reevaluation of the patient's overall status be undertaken, including personal hygiene, exchange technique, presence of diabetes mellitus, malnutrition, and/or other factors that may render the patient more prone to infection with opportunistic pathogens.

Disparate prognosis of thrombotic microangiopathy in HIV-infected patients with and without AIDS.

Thrombotic microangiopathy (TMA) is more common in HIV-infected individuals than in the normal population. In idiopathic TMA, plasmapheresis with or without prednisone decreases the mortality rate from almost 100 to 10%. Patients with HIV-associated TMA, who do not have AIDS, have a similar favorable outcome when treated with plasmapheresis. However, all 12 patients previously reported with AIDS-associated TMA have died. We report another patient with AIDS-associated TMA, who had a fulminant hospital course and died despite plasmapheresis. None of the reported AIDS-associated TMA patients had evidence of opportunistic infections, sepsis or disseminated malignancies at the time of their death. Since many infections and malignancies can be associated with TMA, it is possible that TMA can be an association of the terminal illness rather than an independent cause of death in AIDS patients. To examine this possibility, we reviewed the charts of all the patients who were hospitalized and died of AIDS at our medical centers from 1987 to 1994. Of the 214 patients reviewed, 15 patients (7%) had evidence of TMA at the time of their death. Seven of the 15 patients (47%) had no direct cause of death other than TMA. The remaining 8 patients had evidence of sepsis and other overwhelming infections. In conclusion, TMA is common in AIDS patients. While HIV-associated TMA has a good prognosis similar to that of idiopathic TMA, AIDS-associated TMA has a grave prognosis. The etiology of the higher mortality in AIDS-associated TMA as compared to HIV-associated TMA remains unclear.

Acne: a potential side effect of cyclosporine A therapy.

A renal transplant recipient who developed severe acne 6 months after transplantation is described. Maintenance immunosuppression consisted of cyclosporine A (CsA), azathioprine and prednisone. Tapering the prednisone dose to as low as 5 mg/day, in addition to topical tetracycline, Retin-A cream, and systemic antimicrobial therapy failed to control the progression of the skin lesions. Despite therapy with isotretinoin (Accutane), the lesions continued to progress with nodulocystic transformation (acne conglobata) and isotretinoin was discontinued after 4 months. However, the condition continued to worsen with the development of a systemic illness with daily fever, diaphoresis, and depression. High fever (103 degrees F) with shaking chills prompted hospitalization. Withdrawal of CsA resulted in rapid and continuous improvement of the skin lesions. After 12 months of follow-up, the lesions significantly resolved except for residual areas of scarring. No episodes of acute allograft rejection occurred. In conclusion, we suggest that CsA therapy may be associated with the development of acne. Nodulocystic transformation (acne conglobata) may occur despite the use of isotretinoin. Finally, withdrawal of CsA may lead to resolution of the skin disease and should, therefore, be considered as a therapeutic option for severe and treatment-resistant cases.

Renal transplantation in systemic lupus erythematosus: a single-center experience with sixty-four cases.

The outcome of renal transplantation in 64 patients with end-stage renal disease (ESRD) secondary to lupus nephritis is the subject of this report. The patients were transplanted over a 150-month (12.5-year) period (between July 5, 1979, and January 30, 1992). The study population is predominantly made up of young females (mean age, 34.7 +/- 9 years, n = 54, 81.3%). Fifty-one transplants (79.7%) are cadaveric, and 13 (20.3%) are from living-related donors. Fifty-eight patients (90.6%) had primary (first) allografts, and 6 (9.4%) received a second allograft. Posttransplantation immunosuppression consisted of azathioprine and prednisone (AZA group, n = 22, 34.3%) or AZA, prednisone and cyclosporine (CsA group, n = 42, 65.6%). For all 64 patients combined, the 1-year graft and patient survival rates are 68.8 and 86.5%, respectively, whereas 5-year graft and patient survival rates are 60.9 and 85.9%, respectively. Patients whose immunosuppressive regimen was CsA-based had a 1-year graft survival of 71.5 versus 63.6% in the AZA group. However, this 7.9% difference did not reach statistical significance (p = 0.95). The 5-year graft survival of the CsA-based group was 69.1 versus 45.5% for the AZA group, p < 0.05. One-year patient survival was 77.3% for the AZA group and 92.9% for the CsA group, p < 0.05). The data show that patients with ESRD secondary to lupus nephritis can undergo renal transplantation with satisfactory outcome. Immunosuppression based upon CsA improves first-year patient and allograft survival by 15.6 and 7.9%. respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid-jugular arteriovenous fistula: a complication of temporary hemodialysis catheter.

The internal jugular vein is increasingly being used as a temporary route for dual-lumen hemodialysis catheter placement. It is thought to be safer than the subclavian or femoral vein sites. It is important, however, to point out that this route can also be associated with serious complications. Herein we describe a case of right common carotid artery fistula as a complication of the insertion of a polyurethane double-lumen hemodialysis catheter into the right internal jugular vein. A review of the literature on traumatic complications associated with central venous cannulation is also presented.

Peritoneal dialysis complicated by Bipolaris hawaiiensis peritonitis: successful therapy with catheter removal and oral itraconazol without the use of amphotericin-B.

Fungi classified in the genera Bipolaris are an uncommon source of infection in human diseases. It is also a rare source of peritonitis in peritoneal dialysis (PD) patients. All cases of Bipolaris peritonitis reported in the United States have occurred in the southern states. This form of peritonitis appears to have a good prognosis, with cure achieved only after removal of the peritoneal dialysis catheter and antifungal therapy. Systemic or intraperitoneal amphotericin-B with or without oral ketoconazole has been used in all previously reported cases. However, the role of antifungal therapy is unclear. We report a case of Bipolaris hawaiiensis peritonitis in a 73-year-old female on continuous cyclic peritoneal dialysis (CCPD) for 10 months who presented with a nonfunctioning peritoneal catheter. The catheter had characteristic dark gray particles, each composing a fungal ball within the lumen of the catheter. Microscopic examination confirmed the organism attached to the inner wall of the catheter. The patient achieved cure without using either amphotericin-B or ketoconazole. She was treated with removal of the catheter and a 2-week course of oral itraconazole 100 mg twice daily. A new catheter was placed after 1 month and the patient continued to do well on CCPD 12 months later with no evidence of recurrent infection. We conclude that (1) itraconazole can effect cure following removal of the catheter without using amphotericin-B or ketoconazole; (2) peritoneal dialysis can be safely reinstituted after itraconazole therapy for this uncommon fungal infection, and (3) itraconazole therapy allows for out-patient treatment of B. hawaiiensis peritonitis in peritoneal dialysis patients.

Recombinant human erythropoietin shortens the bleeding time and corrects the abnormal platelet aggregation in hemodialysis patients.

Uremia may be associated with abnormal hemostasis characterized by a prolonged bleeding time and abnormal in-vitro platelet aggregation. The mechanisms underlying these derangements are not fully elucidated. The present study examined the effect of correction of anemia by recombinant human erythropoietin (r-HuEPO) on these abnormalities in eight dialysis patients. Prior to r-HuEPO therapy the patients had low hematocrits (Hct) (20% +/- 0.7), abnormal bleeding times (23 +/- 1.2 minutes), and marked impairment in platelet aggregation induced by adenosine diphosphate (ADP), epinephrine (Epi), thrombin (Th) and collagen. After correction of the anemia to a Hct of 32% +/- 0.9 over 5 +/- 0.9 months, there were a) significant shortening of the bleeding time (from 23 +/- 1.2 to 10.6 +/- 2.4 minutes, p < 0.01), b) an inverse correlation between the Hct and the bleeding time (r = -0.89, p < 0.001) and c) significant improvement, or normalization of platelet aggregation in response to both concentrations of epinephrine [Epi2 (5.4 x 10(-6) M), 45% +/- 10.5 vs 73.5% +/- 7.3, p < 0.01, and Epi1 (5.4 x 10(-5) M), 49% +/- 10.6 vs 64% +/- 6.6, p < 0.05)], both concentrations of ADP [ADPC'(2 x 10(-6) M), 31% +/- 5.9 vs 60% +/- 9.3, p < 0.05, and ADPB (2 x 10-5), 69.5% +/- 7.6 vs 99% +/- 4.8, p < 0.01], and both concentrations of thrombin [ThC (0.22 u/ml) 28.6% +/- 8.9 vs 80.4% +/- 8.3, p < 0.01, and TH50/50 (0.44 u/ml), 57.8% +/- 6.7 vs 83.3% +/- 9.2, p < 0.01)].(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberculosis of the spine (Pott's disease) in patients with end-stage renal disease.

Extrapulmonary tuberculosis is more common in end-stage renal disease than in normal subjects, and it frequently poses both diagnostic and therapeutic challenges. We describe 2 dialysis patients with tuberculosis of the spine (Pott's disease). The 1st patient presented with back and left hip pain, low-grade fever, left-quadriceps weakness, hypoesthesia of the left thigh, and hypoactive left-knee jerk. X-rays of the spine showed only osteophytes. Magnetic resonance imaging showed increased signal intensity of L3 with focal expansion into the spinal canal. A computerized tomography guided biopsy revealed granulomas, and Ziehl-Neelsen stain was positive. Therapy with rifampin, isoniazid, ethambutol, and pyrazinamide caused peripheral neuropathy and optic neuritis. The 2nd patient developed bilateral proximal thigh pain and weakness that progressed to paraplegia. Magnetic resonance imaging showed destructive lesion of L3-5, involving both psoas muscles, prevertebral space, and neural foramina. Ziehl-Neelsen stain of the biopsy specimen was negative, but culture was positive for Mycobacterium tuberculosis. Paraplegia improved only partially after 1 year of therapy. Pott's disease should be suspected in end-stage renal disease patients with back pain and/or neuromuscular complaints, particularly in those who immigrated from Asian and Latin-American countries. Treatment of tuberculosis in dialysis patients may cause significant morbidity.

Unilateral breast enlargement secondary to hemodialysis arteriovenous fistula and subclavian vein occlusion.

Placement of permanent arteriovenous accesses or of temporary subclavian dual-lumen catheters for hemodialysis can be associated with significant edema of the ipsilateral arm due to venous occlusion. We report an unusual case of marked breast enlargement secondary to hemodialysis arteriovenous fistula, and subclavian vein occlusion proximal to the junction of the mammary vein. To our knowledge, this is a rare complication of hemodialysis accesses. Breast enlargement associated with hemodialysis arteriovenous fistulae, especially in the presence of a history of subclavian vein catheterization, may be indicative of ipsilateral subclavian vein stenosis/thrombosis.

Compression of the left brachiocephalic vein by the innominate artery resulting in massive arm edema in a hemodialysis patient.

We report case of extrinsic compression of the left brachiocephalic vein by the innominate resulting in massive edema of the arm in a patient with hemodialysis Gore-Tex graft. To our knowledge, such phenomenon has not been previously reported.

Acute administration of intact parathyroid hormone but not its amino-terminal fragment stimulates volume of pancreatic secretion.

Chronic renal failure is associated with structural and functional abnormalities of the exocrine system of the pancreas. Certain data suggest that the excess parathyroid hormone (PTH) in these patients may participate in the genesis of these pancreatic derangements. However, direct evidence that PTH exerts a direct effect on the exocrine pancreatic system is not well documented. The present study examined the effects of the intact molecule (1-84 PTH) and of the amino-terminal fragment (1-34 PTH) of the hormone on the basal output of pure pancreatic juice (PPJ) volume and pancreatic protein secretion in the rat. 1-84 PTH but not 1-34 PTH significantly (p less than 0.01) stimulated the output of PPJ volume without an effect on protein secretion. The magnitude of this stimulatory effect of 1-84 PTH depended on the dose of the hormone administered, and it was related to its biological activity, since inactivation of PTH abolished its action on the output of PPJ volume. The simultaneous administration of the calcium channel blocker, verapamil, reduced but did not abolish the stimulatory effect of PTH on the volume of PPJ output. The data demonstrate that: (1) the ductal cells of the pancreatic acini are targets for PTH and (2) the action of the hormone on these cells is mediated, at least in part, via PTH-induced entry of calcium into the target cells.

Cyclosporine nephrotoxicity in cardiac allograft patients--a seven-year follow-up.

Renal function was observed retrospectively in a population of 228 adults who underwent a cardiac allograft at the University of Pittsburgh from June 1980 through June 1987, survived a minimum of one year, and received cyclosporine. Renal function was determined by serial measurement of serum creatinine concentration. Serum creatinine rose from 1.2 +/- 0.0 mg/dl at time of hospital discharge to 2.0 +/- 0.0 mg/dl at two and four years and 3.3 +/- 0.1 mg/dl at seven years. The fall in renal function was biphasic, with a rapid decline (reciprocal creatinine slope -0.018 dl/mg-mo) through 24 months and a slower decline thereafter -0.0036 dl/mg/month). This occurred despite a progressive decrease in cyclosporine levels from 668 +/- 23 ng/ml (whole blood RIA) to 380 +/- 12 ng/ml at seven years. Three of 222 patients (1.6%) developed end-stage renal disease within 18 months of initiation of cyclosporine therapy. Only one additional patient of 26 followed through 54 months (3.8%) developed end-stage disease thereafter. The decline in renal function seen with cyclosporine is rapid in the first 18 months, with a slower but continuing decline seen with later follow up. At least in heart transplantation, the risk of end-stage renal disease is significant, but not prohibitive.