Glycophorin-C sialylation regulates Lu/BCAM adhesive capacity during erythrocyte aging.

Lutheran/basal cell adhesion molecule (Lu/BCAM) is a transmembrane adhesion molecule expressed by erythrocytes and endothelial cells that can interact with the extracellular matrix protein laminin-α5. In sickle cell disease, Lu/BCAM is thought to contribute to adhesion of sickle erythrocytes to the vascular wall, especially during vaso-occlusive crises. On healthy erythrocytes however, its function is unclear. Here we report that Lu/BCAM is activated during erythrocyte aging. We show that Lu/BCAM-mediated binding to laminin-α5 is restricted by interacting, in cis, with glycophorin-C-derived sialic acid residues. Following loss of sialic acid during erythrocyte aging, Lu/BCAM is released from glycophorin-C and allowed to interact with sialic acid residues on laminin-α5. Decreased glycophorin-C sialylation, as observed in individuals lacking exon 3 of glycophorin-C, the so-called Gerbich phenotype, was found to correlate with increased Lu/BCAM-dependent binding to laminin-α5. In addition, we identified the sialic acid-binding site within the third immunoglobulin-like domain within Lu/BCAM that accounts for the interaction with glycophorin-C and laminin-α5. Last, we present evidence that neuraminidase-expressing pathogens, such as Streptococcus pneumoniae, can similarly induce Lu/BCAM-mediated binding to laminin-α5, by cleaving terminal sialic acid residues from the erythrocyte membrane. These results shed new light on the mechanisms contributing to increased adhesiveness of erythrocytes at the end of their lifespan, possibly facilitating their clearance. Furthermore, this work may contribute to understanding the pathology induced by neuraminidase-positive bacteria, because they are especially harmful to patients suffering from sickle cell disease and are associated with the occurrence of vaso-occlusive crises.

Association between delirium and death in AIDS patients.

The purpose of this study was to examine the relationship between delirium and death in AIDS patients. Forty-one patients admitted to a combination skilled nursing and assisted-living facility in 1994 were included in the retrospective chart review. Patients were grouped according to the presence versus absence of delirium during the first week of admission. Demographic characteristics and medical morbidity of the two groups were compared using the Chi-square statistic. Kaplan-Meier survival analysis was used to estimate survival functions during the study period for the delirious and nondelirious groups. Nine patients (22%) were found to have an episode of delirium in the first week of admission. There were no significant differences in demographic characteristics or medical morbidity between the delirious and nondelirious groups. Median days from admission to death for those with delirium (10 days) versus those without delirium (135 days) was significantly different (log rank = 19.03; p < 0.0001). Authors concluded that delirium is a marker for decreased survival in this sample of AIDS patients. Future research needs to demonstrate whether improved care of AIDS patients can prevent delirium or limit adverse outcomes associated with it.

Validity of two scales in identifying HIV-associated dementia.

OBJECTIVES: To examine and compare the validity of the HIV Dementia Scale (HDS) and Executive Interview (EXIT) in detecting HIV/AIDS dementia. METHODS: The sample included hospitalized or skilled nursing/assisted-living facility (SNF) HIV/AIDS patients (N = 103). Participants completed the HDS, EXIT, and the Structured Clinical Interview from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). A chart review also was performed. RESULTS: Sample was predominantly male (93%) and white (79%), with a mean age of 38 years (standard deviation [SD] = 8 years). Twelve patients had a clinical diagnosis of HIV dementia. Cutoff scores of 10 or less for the HDS and 11 or more for the EXIT optimized sensitivity and specificity. Education level was related to performance for both tests. Using separate logistic regression analyses, the HDS and the EXIT were significant individual predictors of dementia. When entered together, the EXIT was the only significant predictor of dementia. Selected items of the HDS and EXIT also performed well in identifying patients with dementia. CONCLUSIONS: The HDS and the EXIT show promise as brief, well-tolerated screening tools for HIV dementia in ill patients. The HDS was more sensitive, but the EXIT added additional predictive power over the HDS in identifying dementia.

Delirium in AIDS patients: recognition and medication factors.

The purpose of this study is to determine the frequency of delirium in AIDS patients residing at a skilled nursing facility and to identify factors and outcomes associated with delirium episodes. Medical records were reviewed for 137 patients discharged from or dying at the facility in 1994. Presence or absence of delirium was determined using the Confusion Assessment Method. Patients with delirium were compared to those without delirium regarding demographics, medical conditions, and medication exposure using Mann-Whitney U, chi-square, and two-tailed t-tests. A model for delirium based on medication exposure was determined using multiple logistic regression. Forty-six percent of patients (n = 63) were determined to have at least one delirium episode; only one episode was diagnosed at the time of occurrence. Associated medical conditions included medication changes (44%), fever (38%), and infection (26%). Narcotics, benzodiazepines, anticholinergic/antihistaminic, and steroid medications each contributed significantly to the model for delirium (chi 2 = 60.19; df = 4; p = 0.0000). The authors concluded that delirium is a common yet underidentified condition in AIDS patients, and that patterns of medication use contribute to a large number of delirium episodes.

Psychological and physical factors involved in chronic idiopathic prostatitis.

Idiopathic prostatitis is a common, often chronic condition in which psychological factors are suspected to play a role. Men with chronic prostatitis (n = 51) and a control group of 34 men without any chronic pain condition, equivalent on demographic characteristics, were compared on psychological and perineal muscle tension measures. Prostate-specific antigen and expressed prostatic secretion cell counts were also measured. Chronic prostatitis patients were consistently more elevated than controls on hypochondriasis, depression, and hysteria (MMPI), and on somaticization and depression (Brief Symptom Inventory), and were less elevated on masculine/instrumentality (Personal Attributes Questionnaire) scales. A cluster analysis of MMPI profiles revealed that 57% of the chronic prostatitis patients produced generally unelevated MMPI profiles, whereas the remaining 43% fell into two groups with distinct patterns of distress. The results indicate depression and psychosocial distress are common among chronic prostatitis patients, calling for careful evaluation and attention to psychological symptoms.

Sickness impact of chronic nonbacterial prostatitis and its correlates.

PURPOSE: There is evidence that many patients experiencing chronic idiopathic prostatitis or prostadynia not only have recurrent physical symptoms but also display a range of psychological symptoms, such as depression or anxiety, suggesting that the symptoms of chronic prostatitis may seriously impact on quality of life functioning. We investigated the degree of sickness impact of chronic prostatitis, and the differential importance of physical and psychological symptoms in predicting sickness impact. MATERIALS AND METHODS: The sickness impact profile as well as several symptom measures were administered to 39 patients with chronic prostatitis. Multiple regression analyses were performed to evaluate what proportion of the variance in quality of life or functional status was explained by physical and psychological symptoms. RESULTS: The sickness impact profile mean total score of chronic prostatitis patients was within the range of scores reported in the literature for patients suffering myocardial infarction, angina or Crohn's disease. Pain was the only physical symptom that significantly contributed towards explaining variance in sickness impact. Psychological symptoms added significantly to the amount of predicted variance. CONCLUSIONS: The results indicate a need for careful evaluation and attention to sickness related dysfunctions in patients with chronic prostatitis.

Determination of the colonization resistance of the digestive tract of individual mice.

It has been shown that it is possible to investigate the colonization resistance in individual mice by determining the concentration of a certain contaminant (S.R.-E. coli) in the faeces during the first 4 days after contamination. Experimental contamination is contra-indicated in many cases such as in individuals with decreased resistance to infection. Particularly in this group, the value of the colonization resistance should be determined. It appeared to be possible to determine the colonization resistance in such individuals by quantitative biotyping of the Enterobacteriaceae species in the faeces on several consecutive days.

Colonization resistance of the digestive tract of mice during systemic antibiotic treatment.

During systemic treatment of mice with ampicillin or streptomycin, oral contaminations with exogenous bacterial species resulted in an abnormal colonization pattern. The contaminants persisted much longer and in much higher concentrations in the caecum of systemically treated mice than in control animals. Spread of the contaminant into the mesenteric lymph nodes and the spleen was found much more often in the antibiotic treated group. This, however, was only seen when the contaminant was ;resistant' to the antibiotic injected. The experiments suggest that the ;CR-inducing species' of the microflora live in close contact with the mucosa and therefore could be identical with the anaerobic tapered rods described by Savage & Dubos (1968).