Polyethylene glycol versus low-ionic-strength solution in pretransfusion testing: a blinded comparison study

BACKGROUND: Polyethylene glycol (PEG) has been shown to potentiate antigen-antibody reactions. STUDY DESIGN AND METHODS: To investigate the utility of PEG in pretransfusion testing, a blinded comparison study of PEG and a low-ionic-strength additive solution (LISS) was conducted. A total of 500 patient samples were tested in parallel with reagent antibody-detection cells using blind-coded PEG and LISS potentiators. RESULTS: In 34 (34%) of 100 samples with known antibodies in the Rh, Kell, Duffy, Kidd, and MNS systems, PEG antiglobulin reactions were stronger (total score, 382) than LISS antiglobulin reactions (total score, 216), and in 66 cases (66%), they were equal to those of LISS. Of 400 samples without detectable antibodies, 384 were negative with PEG and LISS, and 16 were positive in PEG tests and negative in LISS. Seven of the 16 were clinically important antibodies (D, 1; E, 3; Fya, 1; Jka; 1; Jkb, 1), and four were clinically benign antibodies (Le(a), 2; McCc, 1; Sda, 1). Five of the 16 demonstrated inconclusive PEG reactions, for a false-positive rate of 5 in 400 (1.3%). Of the 500 samples, none was negative in PEG tests and positive in LISS (0% false-negative rate). CONCLUSION: Although PEG demonstrates a relatively high false-positive rate, PEG is more sensitive than LISS in detecting clinically significant antibodies.     

Anti-thrombotic therapy for non-rheumatic atrial fibrillation

Recent randomized trials of antithrombotic therapy in non-rheumatic atrial fibrillation have helped to clarify the benefits of warfarin and aspirin. Low-risk patients (normotensives aged <60 with normal left ventricular function) have a small risk of thromboembolic events and are unlikely to benefit significantly from anticoagulants, but may benefit from aspirin with little increase in risk of bleeding. High-risk patients (>75 years, impaired left ventricular function, previous thromboembolism and/or associated conditions such as hypertension and diabetes mellitus) have an increased risk of thromboembolism, and benefit from long-term anticoagulant therapy to a greater degree than with aspirin, although at a risk of increased bleeding complications.      

New therapeutic approaches in sepsis: A critical review

This paper reviews several recent, randomized, double-blind, placebo-controlled trials of monoclonal antibodies against endotoxin, interleukin-1 receptor antagonist (IL-1 ra), and monoclonal antibody against tumor necrosis factor (TNF) in sepsis.     

Serologic test for syphilis as a surrogate marker for human immunodeficiency virus infection among United States blood donors

BACKGROUND: This study evaluated the usefulness of the serologic test for syphilis (STS) in preventing the transmission of human immunodeficiency virus (HIV), hepatitis B and C viruses, and human T- lymphotropic virus via the transfusion of seronegative, infectious window-period blood. STUDY DESIGN AND METHODS: Demographic and laboratory information on blood donations made between January 1992 and June 1994 in 18 American Red Cross regions was analyzed. It was assumed that the same proportion of HIV-positive and HIV-infectious window- period donations reacted on STS and were negative on other screening tests (hepatitis B and C viruses and human T-lymphotropic virus). This proportion multiplied by the estimated number of HIV-infectious window- period donations is the number of post-screening HIV-infectious donations removed by STS. RESULTS: Of 4,468,570 donations, 12,145 (0.27%) were STS positive and 377 (0.008%) were HIV positive. Among donations that were negative on other screening tests, STS-reactive donations were 12 times more likely to be HIV positive (odds ratio = 11.9; 95% CI = 5,26). However, of an estimated 13 infectious window- period donations, 0.2 would have been removed because of a reactive STS, at a cost of over $16 million. CONCLUSION: STS is a poor marker and a costly strategy for preventing post-screening HIV infections and other blood-borne diseases.     

The pharmacology of a new pasteurized antihemophilic factor concentrate derived from human blood plasma

The pharmacology of a new pasteurized factor VIII (FVIII) concentrate derived from human blood plasma was studied in 23 adults with hemophilia A. In Part 1 of the study involving six nonbleeding subjects, the mean increase in FVIII activity was 1.43 +/- 0.34 U per ml 10 minutes after an intravenous dose of 50 U per kg. The intravascular survival kinetics in these six patients showed a biphasic decay curve with an initial mean half-life of 5.1 +/- 1.2 hours probably representing early redistribution, and a late half-life of 13.3 +/- 4.9 hours. In Part 2 of the study, the activity at 10 minutes was measured in another 17 patients, as well as in one patient already studied in Part 1. The mean increase in activity with the 24 observations was 1.13 +/- 0.37 U per ml with a mean FVIII dosage of 51.0 +/- 2.6 U per kg of body weight. Only one patient had an allergic reaction, which did not recur when the patient was given a second lot.     

In vitro and in vivo activity of murine lymphokine-activated killer cells after cryopreservation

The in vitro and in vivo effects of cryopreservation on the cytotoxic activity of murine lymphokine-activated killer (LAK) cells were studied. LAK cells were generated by incubation of spleen lymphocytes of BALB/c mice for 3 days with recombinant interleukin-2 (rIL-2) and subsequent cryopreservation. Cytotoxicity was determined in a 51Cr release assay. After thawing, cytotoxic activity was reduced (40.4% 51Cr release at an effector:target cell ratio of 40:1 as compared to 68.5% 51Cr release before freezing) and could be restored to precryopreserved levels by reincubation with rIL-2 for 2 days after thawing (78.8% 51Cr release). These cells were then tested in BALB/c mice injected with RAW 112 cells, a pre-B-cell lymphoma line. The results demonstrate that the survival rate of mice injected with cryopreserved and restimulated LAK cells (50% survival greater than 180 days after injection) did not differ significantly from that of mice injected with fresh unfrozen LAK cells (60% survival greater than 120 days, 50% survival greater than 180 days). Cryopreserved LAK cells have potential use in adoptive immunotherapy.     

Respiratory insufficiency in neuronopathic and neuropathic disorders

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barre syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.      

Combination of theophylline and salbutamol for arrhythmias in severe COPD

We conducted a single-bind placebo controlled study using 24-hour continuous ambulatory electrocardiographic recordings. The arrhythmogenic potential of the combination of salbutamol and theophylline was investigated in 25 ambulatory subjects with severe chronic airflow obstruction (mean age 65 +/- 8 SD, mean FEV1 31 percent +/- 13 SD predicted). Asymptomatic arrhythmias were very prevalent in the study population: 76 percent of the patients had runs of supraventricular tachycardia while 24 percent had runs of ventricular tachycardia. Individual arrhythmia frequency showed greater between-test variability than previously described in non-COPD subjects. The mode of administration of salbutamol may have affected arrhythmia frequency in that subjects using aerosol nebulizers had more ventricular extrasystoles than those using metered dose inhalers. Although the addition of theophylline to salbutamol significantly increased heart rate and supraventricular extrasystoles, there was no statistically significant increase in ventricular arrhythmias.     

A fuzzy logic model for differential diagnosis of lower urinary tract dysfunctions

Lower urinary tract dysfunctions (LUTD) restrict quality of life, resulting in decreased work productivity and emotional well‐being. However, most people are not diagnosed because they do not seek medical treatment. In addition, some facilities do not adequately train health professionals in the evaluation, diagnosis and treatment of these conditions. The study's objective was to develop a decision support system modelled on fuzzy logic that defines LUTD using the terminology of the International Continence Society. This methodological study aimed to develop a model that uses the maximum–minimum composition (max–min) of fuzzy relations that can perform differential diagnoses of LUTD. The model was tested in 100 cases (50 men and 50 women), and the data were obtained from medical records containing the clinical data and results of urodynamic studies. All medical records were reviewed by a specialist in urology. The model was capable of determining a diagnosis in full (62%) or partial (36%) agreement with the medical report. Agreement between the model and the medical report was excellent (kappa = 0·98, p ? 0·001, CI = 0·88–1) or substantial (kappa = 0·53, p ? 0·001, CI = 0·45–0·60), considering overestimative accordance (where accordance is assumed when at least one diagnosis is equal) and underestimative accordance (where accordance is assumed when all diagnoses are equal), respectively. The proposed model based on the max–min composition of fuzzy relationships is very simple and performed well. However, more tests are recommended before the model is used as a decision support system.