The role of polyphosphoinositides in agonist-evoked release of vasoactive factors from astrocytes.
Explore the source record for details and available documents.
Adenosine Triphosphate↗
Biomedical subjects
S Murphy
Publications and source records attributed to S Murphy.
Lack of care giver hand contamination with endemic bacterial pathogens in a nursing home.
Prevalences of Clostridium difficile and multiply resistant Staphylococcus aureus (MRSA) were determined in nursing staff and residents of a 233-bed long-term care facility. Twenty of 38 (52.6%) patients in the long-term care ward and three of 69 (4.3%) in the skilled-nursing ward were colonized with MRSA; 16 of 48 (33%) patients in the long-term care ward and seven of 52 (13%) in the nursing home ward were colonized with C. difficile. None of the 79 staff members whose hands were cultured had chronic C. difficile hand carriage and MRSA was present on only three of 79 (3.9%). Over a 6-month period, 128,000 pairs of gloves were worn. Since C. difficile and MRSA are rarely present on washed hands of care providers, appropriate handwashing and gloving should make a significant contribution to reducing the spread of these agents in long-term care facilities.
Adult↗
Amphotericin B and platelet transfusion.
Explore the source record for details and available documents.
Amphotericin B↗
Platelet quality after 15-day storage of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium.
It has been reported previously that platelet concentrates (PCs) prepared from buffy coat pools diluted in a simple, glucose-free medium (BC-PCs) are effective in thrombocytopenic patients after 4 to 12 days of storage. Such preparations produce platelet increments similar to those of traditional PCs prepared from platelet-rich plasma (PRP-PCs) stored for 1 to 3 days. The purpose of this study was to obtain a series of in vitro measurements during storage to allow a more detailed characterization of BC-PCs and a more detailed comparison of BC-PCs with PRP-PCs. At the beginning of storage, the level of (alpha granule membrane protein-140 (GMP-140), a marker of platelet activation, was significantly higher on PRP-PC platelets, and BC-PCs were superior in measurements reflecting platelet function, such as osmotic reversal, ATP release, and aggregation with collagen. Compared to PRP-PCs, BC-PCs were superior in the percentage of discs, total ATP, and glycoprotein lb expression by Day 7. This superiority became more striking on Day 11. Overall, 15-day-old BC-PCs compared favorably to 7-day old PRP-PCs: BC-PCs were superior in ATP release and aggregation with collagen, but they were not significantly different for all other measurements reflecting platelet quality and function. Thus, the quality of platelets in BC-PCs was superior on Day 1, and this superiority progressed as storage continued. In addition, the metabolism of BC-PCs was favorable.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Platelets↗
Role of acetate during platelet storage in a synthetic medium.
It has previously been shown that buffy coat platelet concentrates (BC-PCs) stored in a medium made up of approximately 70 percent platelet storage medium (Plasma-Lyte A, PL) and 30 percent plasma (BC-PC-P) are effective in vivo after 9 to 12 days of storage. In addition to sodium, potassium, magnesium, and chloride, PL contains 27 mM (27 mmol/L) sodium acetate and 23 mM (23 mmol/L) sodium gluconate. This study investigated the effect of acetate and gluconate on platelet metabolism. Identical BC-PCs were stored at 22 +/- 2 degrees C in PL (BC-PC-P); PL with gluconate but without acetate, termed PL-A (BC-PC-A); or PL with acetate but without gluconate, termed PL-G (BC-PC-G). On Day 1 of storage, no significant differences were seen between the three groups of BC-PCs. In both BC-PC-P and BC-PC-G, pH and bicarbonate were stable at 7.0 +/- 0.03 and 8.4 +/- 0.9 mEq per L throughout 10 days of storage, whereas in BC-PC-A, they fell to 6.7 +/- 0.05 and 5.5 +/- 0.8 mEq per L on Day 5 (p less than 0.01 vs. Day 1) and to 6.1 +/- 0.1 and 1.2 +/- 0.4 mEq per L, respectively, on Day 10. The buffering capacities of 70 percent PL, PL-A, or PL-G and 30 percent plasma were similar in a platelet-free setting when incremental additions of lactic acid were made. The role of acetate was further studied by adding 14C- or 3H-labeled acetate to BC-PC-P.(ABSTRACT TRUNCATED AT 250 WORDS)
Acetates↗
Impact of vitamin A supplementation on the incidence of infection in elderly nursing-home residents: a randomized controlled trial.
The aim of this study was to determine if vitamin A supplementation reduces the incidence of bacterial infections among elderly nursing-home residents. One hundred and nine patients were enrolled into a double-masked, placebo-controlled trial at an academically affiliated nursing home. Fifty-six patients received a single capsule containing 1,000 IU of vitamin A (placebo) and 53 received a single capsule containing 200,000 IU of vitamin A. Antibiotic-treated infections were enumerated for 90 days after dosing and infection rates were expressed per 1000 days of follow-up. There were 42 antibiotic-treated infections altogether, 21 in each group. The infection rates in the vitamin A and placebo groups were 4.7 and 4.3 per 1,000 days of follow-up, respectively (relative risk 1.1; 95% CI 0.6, 2.0). The findings of this study do not support a role for vitamin A supplements for the prevention of infections among frail elderly nursing-home patients.
Aged↗
Applications and limitations of vitreoretinal biopsy techniques in intraocular large cell lymphoma.
The cases of 4 patients with clinical signs of intraocular large cell lymphoma are described. Initial cytopathologic examination of vitrectomy specimens failed to establish the malignant character of the vitreous infiltrates. Three of the four patients eventually developed solid central nervous system tumors, intracranial biopsy samples of which revealed large cell lymphoma, 13 months to 42 months after initial examination. In one patient, transscleral retinochoroidal biopsy confirmed the diagnosis at the same time as negative vitreous cytologic examination. Results of cytopathologic examination alone of vitreous biopsy specimens may not be sufficient to make a diagnosis in certain cases of large cell lymphoma that are subsequently documented by CNS biopsy. Careful attention should be paid to the handling, processing, and interpretation of vitrectomy specimens from patients suspected of having intraocular large cell lymphoma. Consideration should be given to immunocytologic staining and interpretation by centers that are highly experienced in vitreous cytopathology.
Biopsy↗
Amino acid metabolism during platelet storage for transfusion.
Previous studies indicated that the concentration of ammonia rises during storage of platelet concentrates (PC) at 22 degrees C for transfusion and that fuels other than glucose are important for metabolism. Therefore, in the current study, we measured the concentrations of 17 plasma amino acids during PC storage; 16 of these either rose or were unchanged while the concentration of glutamine fell to zero by day 4. As the concentration of glutamine fell, the concentration of glutamate rose with a relationship suggesting that 65-75% of the glutamine was metabolized no further than glutamate. Phosphate-dependent glutaminase activity was present in platelets at 22.3 +/- 6.3 nmol/min/mg protein, a level similar to that seen in lymphocytes and macrophages. Leucodepletion studies excluded a significant contribution of contaminating leucocytes to these measurements. Thrombin stimulation did not increase the rate of glutamine metabolism. Analysis of the rates of glutamine metabolism suggests that it accounts for most of the ammonia produced during PC storage. However, it appears to be relatively insignificant as a metabolic fuel. The role of glutamine metabolism for platelets is uncertain. It may be a vestige of a pathway in the megakaryocyte. The ammonia which it produces may be deleterious for platelets and for patients with liver disease who receive PC infusions.
Amino Acids↗
Body composition and bone mass in post-menopausal women.
OBJECTIVE: We aimed to assess total body composition and to study the interrelationships between fat and lean tissue mass with total and regional bone mass in healthy British post-menopausal women. DESIGN AND PATIENTS: Total body composition and regional bone mass were measured in 97 healthy post-menopausal women recruited from the general community. The mean age was 57.9 years, range 49-65. MEASUREMENTS: Total body composition (fat, lean tissue and bone mineral) and regional bone density in the lumbar spine and femur were measured by dual energy X-ray absorptiometry on a Lunar DPX. RESULTS: Significant negative correlations with age were found for total body bone mineral density (r = -0.200, P = 0.049), and lumbar spine bone mineral density (r = -0.28, P = 0.006); the calculated rate of bone loss from these two sites was 0.33 and 0.7% per annum respectively. Fat tissue mass showed a positive correlation with age (r = 0.22, P = 0.03). High correlations were observed between total body and regional bone mineral density (r = 0.755-0.829, P < 0.001). After adjustment for age and lean mass, statistically significant correlations were seen between fat tissue mass and all bone mass measurements (P < 0.01-0.001), the strongest correlations being found for total body bone mineral content and density (r = 0.477 and 0.488 respectively). Lean tissue mass showed a strong correlation with total body bone mineral content (r = 0.580, P < 0.001), after adjustment for age and fat mass; it was less strongly correlated with other bone mass measurements than fat mass, showing only weak correlations with total body, trochanteric and lumbar spine bone mineral density (r = 0.228-0.246, P < 0.05). Age-adjusted body weight showed stronger correlations with total and regional bone mass than did either body mass index or height. CONCLUSIONS: Both fat and lean tissue mass are related to total and regional bone mass in post-menopausal women, the relationship being strongest for fat mass. Body weight shows stronger correlations with bone mass than either height or body mass index. In view of the direction and magnitude of changes in fat, lean tissue and bone mineral after the menopause, adiposity and muscularity are more likely to be determinants of peak bone mass than of the rate of post-menopausal bone loss.
Absorptiometry, Photon↗
Should all platelet concentrates issued be leukocyte-poor?
Explore the source record for details and available documents.
Blood Component Transfusion↗
Induction of nitric oxide synthase in glial cells.
Primary astrocyte cultures, C6 glioma cells, and N18 neuroblastoma cells were assayed for nitric oxide synthase (NOS) activity with a bioassay of cyclic GMP production in RFL-6 fibroblasts. Treatment of astrocyte cultures for 16-18 h with lipopolysaccharide (LPS) induced NOS-like activity that was L-arginine and NADPH dependent, Ca2+ independent, and potentiated by superoxide dismutase. Induction was evident after 4 h, was dependent on the dose of LPS, and required protein synthesis. Treatment of astrocyte cultures with leucine methyl ester reduced microglial cell contamination from 7 to 1%, with a loss of 44% of NOS-like activity. C6 cells treated with LPS also showed Ca(2+)-independent and L-arginine-dependent NOS-like activity. N18 cells demonstrated constitutive Ca(2+)-dependent NOS-like activity that was not enhanced by LPS induction. These data indicate that NOS-like activity can be induced in microglia, astrocytes, and a related glioma cell line as it can in numerous other cell types, but not in neuron-like N18 cells.
Amino Acid Oxidoreductases↗
Methicillin-resistant Staphylococcus aureus colonization in a long-term-care facility.
OBJECTIVE: To study the prevalence and risk factors for colonization with MRSA at a long-term-care facility. DESIGN: Cross-sectional surveillance culture survey. SETTING: A 233-bed university-affiliated long-term-care facility. MEASUREMENTS: Surveillance cultures for MRSA were performed on patients of two adjacent nursing units and on new admissions to the entire facility over a 4-month period. RESULTS: On the chronic medical unit, where patients known to be colonized had been cohorted, 20 of 38 (52.6%) were colonized vs 3 of 67 (4.5%) on the skilled/intermediate unit (P less than 0.001), suggesting that little intra-facility spread of MRSA occurs. Twenty-four of 55 (43.6%) chronic medical admissions were colonized vs 6 of 63 (9.5%) admitted to the other units (P less than 0.001). Thirteen of 30 (43.3%) admissions were not previously known to be colonized. By univariate analysis, colonized admissions were younger and more often male; had more listed diagnoses, including pressure sores, a previous positive MRSA culture, and urinary incontinence; were more often fed by feeding tube; and had longer durations of hospital stay prior to admission. Logistic regression analysis showed that the most powerful independent predictors of colonization at admission were: a prior positive culture for MRSA (OR 8.8, 95% CI 2.4, 32.4), male sex (OR 8.2, 95% CI 2.3, 29.7), urinary incontinence (OR 3.8, 95% CI 1.4, 10.4), and presence of pressure sores (OR 2.9, 95% CI 0.9, 9.2). CONCLUSIONS: Unrecognized colonization of nursing home residents with MRSA is common, and nursing homes are unwittingly repositories for patients colonized with MRSA following acute hospitalization. Gloving and careful attention to handwashing may limit spread of MRSA within nursing homes, and identification of colonized patients may be facilitated by targeted surveillance cultures of the most debilitated patients at admission.
Aged↗
Oct-1 and Oct-2 potentiate functional interactions of a transcription factor with the proximal sequence element of small nuclear RNA genes.
The promoters of both RNA polymerase II- and RNA polymerase III-transcribed small nuclear RNA (snRNA) genes contain an essential and highly conserved proximal sequence element (PSE) approximately 55 bp upstream from the transcription start site. In addition, the upstream enhancers of all snRNA genes contain binding sites for octamer-binding transcription factors (Octs), and functional studies have indicated that the PSE and octamer elements work cooperatively. The present study has identified and characterized a novel transcription factor (designated PTF) which specifically binds to the PSE sequence of both RNA polymerase II- and RNA polymerase III-transcribed snRNA genes. PTF binding is markedly potentiated by Oct binding to an adjacent octamer site. This potentiation is effected by Oct-1, Oct-2, or the conserved POU domain of these factors. In agreement with these results and despite the independent binding of Octs to the promoter, PTF and Oct-1 enhance transcription from the 7SK promoter in an interdependent manner. Moreover, the POU domain of Oct-1 is sufficient for significant in vitro activity in the presence of PTF. These results suggest that essential activation domains reside in PTF and that the potentiation of PTF binding by Octs plays a key role in the function of octamer-containing snRNA gene enhancers.
Base Sequence↗
Epidermal growth factor receptors in the oesophagus.
The quantity and distribution of epidermal growth factor receptors (EGF-R) in oesophageal mucosa was studied in the oesophagus in order to determine its role in oesophageal disease. Fifty five biopsies were taken from different levels of the oesophagus in 25 consecutive patients undergoing endoscopy. Another group of eight patients with histologically proven Barrett's oesophagitis had a biopsy taken from the area of columnar lined oesophagus. A peripheral, membranous pattern was seen predominantly confined to the basal and immediately suprabasal cells in all of the first group of patients. In the superficial cells a few granular cytoplasmic structures were positive. All patients with Barrett's oesophagitis showed EGF-R staining of the surface epithelium. A computerised planimeter was used to determine the proportion of stained areas of squamous cells which were expressed as a percentage of the total area of squamous cells. The difference in the area of cells stained for EGF-R between normal and inflamed oesophageal mucosa (29.5% and 43.1% respectively) was significant (p less than 0.001).
Adult↗
Endogenous sex hormones and bone mineral density among community-based postmenopausal women.
In order to describe the relationships between endogenous sex hormones and bone mineral density in healthy postmenopausal women, we carried out a cross-sectional study of 90 community-based women, all at least one year since their last menstrual period (mean 9.6 +/- 4.9 years, range 1-22) and with a serum oestradiol level less than 100 pmol/l. None was currently using hormone replacement therapy. Serum oestradiol, testosterone, sex hormone binding globulin, dehydroepiandrosterone sulphate, and androstenedione were measured using standard techniques. Free oestradiol and testosterone indices were derived as the ratio of total hormone to sex hormone binding globulin, respectively. Total body, spine and hip bone mineral density (g/cm2) were measured by dual energy X-ray absorptiometry. Significant positive correlations were found between the free oestradiol and testosterone indices and bone mineral density at all sites. These relationships remained significant for the free oestradiol index after adjustment for age and body mass index. By stepwise multiple regression analysis, the free oestradiol index was an independent predictor of total body, spine and hip bone mineral density, accounting for 4-17% of the variance. These findings suggest an independent positive relationship between endogenous free oestradiol and total body, spine and hip bone mass even in the late postmenopause.
Aged↗
Polycythemia vera and myelofibrosis: correlation of MR imaging, clinical, and laboratory findings.
Magnetic resonance (MR) imaging was performed in 14 patients with biopsy-proved polycythemia vera (n = 4) or myelofibrosis (n = 10) to determine whether MR imaging findings can be correlated with the clinicopathologic diagnosis and established clinical parameters of severity (serum lactate dehydrogenase [LDH] and cholesterol levels) and chronicity (spleen size). Evaluation of marrow in the proximal femurs showed that patients could be categorized into three distinct groups based on anatomic patterns of normal fatty and abnormal low-signal-intensity (non-fatty) marrow in the femoral capital epiphysis (FCE) and greater trochanter (GT). Patients with nonfatty marrow in both the FCE and GT (n = 8) had significantly higher serum LDH (P less than .02) and lower serum cholesterol (P less than .02) levels than patients with fatty marrow in at least the GT (n = 6). Splenic volume, as measured from MR images, was significantly greater in the myelofibrosis group than in the polycythemia vera group (P less than .001). MR imaging provided a better understanding of these hematologic disorders and novel parameters for classification that are different from conventional histologic and laboratory data.
Adult↗
Evolution of therapy for childhood asthma.
Explore the source record for details and available documents.
Aerosols↗
Beta-adrenergic agonists for acute, severe asthma.
OBJECTIVE: To critically review the use of beta-adrenergic agonists in acute, severe asthma with particular focus on aerosol administration. DATA SOURCES: English language articles published since 1971 on the use of beta-agonists for acute asthma. Studies were identified from bibliographies of book chapters, review articles, and other research articles. STUDY SELECTION: All studies (21 total) comparing systemic with inhaled beta-agonists were reviewed, regardless of their design or outcome. Selected studies highlighting specific aspects of beta-agonist use in acute asthma such as beta-agonists versus other bronchodilators, aerosol delivery, and intravenous beta-agonists were also reviewed. DATA EXTRACTION: Performed subjectively by the authors with specific aspects of quality discussed within the body of the article. DATA SYNTHESIS: The beta-agonists provide superior bronchodilation in acute severe asthma compared with either the methylxanthines and/or anticholinergics. The majority of studies found aerosolized beta-agonists to be either as effective as or more effective than parenteral beta-agonists and to produce fewer adverse cardiovascular effects. Studies showing preference for parenteral therapy have either been of poor design or used low doses of an aerosolized beta-agonist. Based on studies of aerosol delivery, there is no advantage of jet nebulization over metered-dose inhalers; however, other aspects, including ease of administration, favor nebulization as the delivery method of choice. The articles recommending intravenous beta-agonists consist of a series of uncontrolled cases. CONCLUSIONS: Aerosolized selective beta 2-agonists are the bronchodilator treatments of choice for acute, severe asthma. Attention to the details of dosing and delivery are required for optimal results. The final dose and dosing interval are determined by the patient's response. Intravenous beta-agonists are hazardous and cannot be recommended.
Administration, Inhalation↗