Anaphylactoid reactions associated with reuse of hollow-fiber hemodialyzers and ACE inhibitors.

From July 18 through November 27, 1989, 12 anaphylactoid reactions (ARs) occurred in 10 patients at a hemodialysis center in Virginia. One patient required hospitalization; no patients died. ARs occurred within minutes of initiating dialysis and were characterized by peripheral numbness and tingling, laryngeal edema or angioedema, facial or generalized sensation of warmth, and/or nausea or vomiting. All 12 ARs occurred with dialyzers that had been reprocessed with an automated reprocessing system. A cohort study, including all patients undergoing dialysis sessions on the six days when an AR occurred, showed that the patients who experienced ARs were significantly more likely than patients who did not to be treated with angiotensin-converting enzyme (ACE) inhibitors (7/10 vs. 3/33; relative risk = 7.9; 95% confidence interval = 2.5 to 25.2) and to have been exposed to reused dialyzers rather than to new dialyzers (12/70 sessions vs. 0/31; P = 0.016). In those sessions using a reused dialyzer, the mean number of dialyzer uses in case-sessions was significantly higher than for noncase-sessions (10.3 vs. 6.2; P = 0.016). After reuse of dialyzers was discontinued at the center, no further ARs occurred, despite the continued administration of ACE inhibitors. This is the first report of an outbreak of ARs associated exclusively with reused dialyzers. We hypothesize that interactions between a dialyzer that has been repeatedly reprocessed and reused, blood, and additional factors, such as ACE inhibitors, increased the risk of developing ARs.     

Outbreak of gram-negative bacteremia and pyrogenic reactions in a hemodialysis center

During the period from April 4, 1988, to April 20, 1988, nine pyrogenic reactions and five gram-negative bacteremias occurred in 11 patients undergoing dialysis. All pyrogenic reactions and gram-negative bacteremias occurred among patients in whom a reprocessed dialyzer was used. The rate of pyrogenic reactions or bacteremias per 100 sessions using a reprocessed dialyzer was higher than in sessions during which a new dialyzer was used (4.5 vs. 0; p = 0.03). Dialyzers were manually reprocessed with 2.5% Renalin germicide. The Renalin concentrations varied widely in 12 dialyzers stored after manual reprocessing during the epidemic period (0.9-4.2%); the median endotoxin concentrations varied from 0 to 246 ng/ml and were higher in dialyzers with Renalin concentrations less than or equal to 1.0% than in dialyzers with higher concentrations (p = 0.01). Experiments using a dilution technique described by a technician resulted in Renalin concentrations ranging from 1.4% at the surface to 3.5% at the bottom of the preparation container. These findings suggest that failure to adequately admix Renalin during dilution may be associated with low levels of disinfectant, high levels of bacteria and endotoxins in dialyzers, and outbreaks of pyrogenic reactions and gram-negative bacteremias in dialysis patients.     

Association between presenilin-1 -48C/T polymorphism and Down's syndrome

Individuals with Down's syndrome (DS), i.e., trisomy 21, over 40 years of age, are likely to develop neuropathological changes characteristic of Alzheimer's disease (AD). The involvement of chromosome 21 both in DS and AD suggests a shared genetic susceptibility to these disorders, but genetic determinants are still undefined. The -48C/T polymorphism in the PSEN1 promoter is a possible candidate, since it has recently been associated with an increased risk of early onset AD. Based on the assumption that the excess of dementia in DS might be a consequence of a different distribution of the -48C/T polymorphism, we investigated the association between DS and this polymorphism in patients with trisomy 21 and controls. Overall, 260 DS patients and 197 controls were recruited at the Department of Neurosciences, Tor Vergata University of Rome. Cases and controls had similar age and gender distribution. High molecular weight DNA was extracted from whole blood samples collected in EDTANa(2) and -48C/T genotypes were determined. Genotype and allele frequencies were compared between cases and controls. Cases were less likely than controls to have the CC genotype ( P = 0.05). A significant difference for allele distribution between DS cases and controls was found, with DS showing a lower frequency of the allele C compared with the control population (OR: 0.57; 95% CI: 0.35-0.91; P = 0.01). No significant interaction of PSEN1 with age, gender, ApoE and -850 TNF-alpha polymorphisms was found. The association found suggests that the -48C/T polymorphism in the PSN1 gene promoter, which is involved in the modulation of amyloid beta load in human AD, is associated with DS. However, the biological role of this polymorphism in DS-related dementia remains unclear and merits further investigation.     

HEp-2 Cell-Adherent Escherichia coli and Intestinal Secretory Immune Response to Human Immunodeficiency Virus (HIV) in Outpatients with HIV-Associated Diarrhea

HEp-2 cell-adherent Escherichia coli and the human immunodeficiency virus (HIV) itself have recently been incriminated as causes of chronic HIV-associated diarrhea. This study sought to determine the prevalence of these two agents among HIV-infected patients with diarrhea in an outpatient setting in the United States and to compare their prevalence to that of other commonly recognized enteropathogens known to be present in this population. HEp-2 cell-adherent E. coli was found in 20 of 83 (24.1%) patients with diarrhea. A diffuse pattern of adherence was the most common, found in 14 of 20 (70%) patients, followed by a localized adherence pattern (6 of 20; 30%). An intestinal secretory immune response against the p24 antigen of HIV was found in 9 of 34 (27.5%) patients with HIV-associated diarrhea. The following pathogens or products were also detected in lower frequencies: Cryptosporidium spp. (10.8%), Clostridium difficile toxin (8.8%), microsporidia (6%), Isospora belli (3.6%), Blastocystis hominis (2.4%), Giardia spp. (1.2%), Salmonella spp. (1.2%), and Mycobacterium spp. (1.2%). The role of HEp-2 cell-adherent E. coli and HIV enteric infections in patients with HIV-associated diarrhea deserves further study.     

Lexical effects in left neglect dyslexia: A study in Italian patients

This study investigated whether and to what extent the reading performance of six Italian right-brain-damaged patients with left neglect dyslexia was affected by lexical variables. The lexicality of responses (either words or nonwords) and the distribution of substitution vs. omission neglect errors were measured. Patients were given the following tasks: (1) reading aloud monomorphemic words of different frequencies and nonwords with different degrees of similarity to real words (Experiment 1); (2) reading aloud morphologically complex (suffixed) derived words and morphologically complex (suffixed) nonwords (Experiment 2). Patients could be distinguished in terms of their sensitivity to the lexical status of the target. Four patients exhibited lexicality effects in their reading performance, while two patients did not. The dissociation is discussed in terms of the interaction between defective visuospatial analysis, which characterises neglect, and higher-order lexical knowledge. The suggestion is made that lexical effects in neglect dyslexia reflect a relative preservation of visuospatial processing of the left side of the letter string, its absence a more severe neglect disorder. This interpretation of the occurrence of lexical effects in left neglect dyslexia in terms of severity of the spatial disorder is specific to the domain of reading, however, and does not extend to other manifestations of unilateral spatial neglect. Finally, the relationship between error type (omissions vs. substitutions) and the absence vs. presence of lexical effects is considered.     

Bacteriologic and endotoxin analysis of salvaged blood used in autologous transfusions during cardiac operations.

Autologous blood transfusion is a common method of reducing the need for heterologous blood transfusion during cardiac operations. Recently we investigated an outbreak of severe, nonsurgical postoperative bleeding among patients undergoing heart operations and receiving intraoperative transfusion of blood from a cell conservation device (Cell Saver System, Haemonetics Corp., Braintree, Mass.). As a result of this investigation, we conducted a prospective study to determine if bacterial or endotoxin contamination of the blood collected in the Cell Saver System and used for reinfusion during heart operations contributes to postoperative bleeding complications. Patients' blood samples were collected immediately before operation, at the end of cardiopulmonary bypass, 1 hour postoperatively, and from the Cell Saver System. All blood samples were cultured for bacteria, and all plasma samples were assayed for endotoxin. Preoperatively all patients having heart operations were without signs of infection, 33 of 37 blood cultures taken were negative, and none of the plasma samples had detectable endotoxin. After discontinuance of cardiopulmonary bypass but before delivery of blood from the Cell Saver System, bacteria and endotoxin were detected in 11 of 36 (30.6%) and five of 35 (14.3%) of the patients' blood samples, respectively. The blood aspirated from the open chest and collected by the Cell Saver System was culture positive in 30 of 31 (96.8%) samples, and seven of 29 (24.1%) contained endotoxin. One of 28 blood samples collected 1 hour postoperatively was culture positive, and five of 25 samples contained endotoxin. Of 61 total microorganisms isolated, 50 (82%) were coagulase-negative staphylococci, four (6.6%) aerobic diphtheroids, five (8.2%) anaerobic "diphtheroids" (Propionibacterium acnes), and two (3.2%) gram-negative bacilli. Plasma endotoxin concentrations ranged from 10 to 765 pg/ml. No signs of endotoxemia or unusual bleeding were observed intraoperatively or postoperatively in any of the 38 patients. Although blood collected in the Cell Saver System and used for reinfusion during heart operations often was contaminated with gram-positive bacterial commensals of the skin and low concentrations of endotoxin, no adverse effects were noted in the patients.     

Epidemic parenteral exposure to volatile sulfur-containing compounds at a hemodialysis center.

OBJECTIVE: To determine the cause of acute illness on August 30, 2000, among patients at an outpatient dialysis center (center A). DESIGN: We performed a cohort study of all patients receiving dialysis on August 30, 2000; reviewed dialysis procedures; and analyzed dialysis water samples using microbiologic and chemical assays. SETTING: Dialysis center (center A). PATIENTS: A case-patient was defined as a patient who developed chills within 5 hours after starting hemodialysis at center A on August 30, 2000. RESULTS: Sixteen (36%) of 44 patients at center A met the case definition. All case-patients were hospitalized; 2 died. Besides chills, 15 (94%) of the case-patients experienced nausea; 12 (75%), vomiting; and 4 (25%), fever. Illness was more frequent on the second than the first dialysis shift (16 of 20 vs 0 of 24, P < .001); no other risk factors were identified. The center's water treatment system had received inadequate maintenance and disinfection and a sulfurous odor was noted during sampling of the water from the reverse osmosis (RO) unit. The water had elevated bacterial counts. Volatile sulfur-containing compounds (ie, methanethiol, carbon disulfide, dimethyldisulfide, and sulfur dioxide) were detected by gas chromatography and mass spectrometry in 8 of 12 water samples from the RO unit and in 0 of 28 samples from other areas (P < .001). Results of tests for heavy metals and chloramines were within normal limits. CONCLUSIONS: Parenteral exposure to volatile sulfur-containing compounds, produced under anaerobic conditions in the RO unit, could have caused the outbreak. This investigation demonstrates the importance of appropriate disinfection and maintenance of water treatment systems in hemodialysis centers.