Comparison of bacteria growth in single and pooled platelet concentrates after deliberate inoculation and storage

BACKGROUND: The ability to store pools of platelet concentrates (PCs) for extended periods would provide logistical flexibility. However, reports of severe adverse reactions due to the transfusion of contaminated PCs led to an examination of whether the total bacteria levels after storage of pools containing a deliberately inoculated platelet unit would be significantly different than the levels in paired unpooled concentrates. STUDY DESIGN AND METHODS: A single PC was deliberately inoculated on Day 0 with one of three bacterial species (0.1–8.0 colony-forming units/mL). On Day 1, the deliberately inoculated PC was divided into three equal parts and either 1) pooled with 5 half-volume, ABO- and Rh-identical PCs; 2) similarly pooled and white cell reduced; or 3) kept as a control. Sterile connections were used during pooling; modified storage containers were used to ensure the correct surface-to-volume ratio of the single unit. RESULTS: Between Day 2 and Day 5 of storage, in 26 of 36 paired samples, nonfiltered pools containing Escherichia coli had greater total numbers of bacteria than did the paired single PCs. Day 2 pools had total bacteria levels approximately five times higher (colony-forming units/mL × container volume) than those in single units (p < 0.05). There was rapid growth of Staphylococcus aureus by Day 2 in pooled and unpooled PCs; by Day 3, total bacteria levels were approximately five times higher in pools than in single units (p < 0.05). Between Days 3 and 5 of storage, in 23 of 27 paired samples, nonfiltered pools containing S. aureus had greater total bacteria levels than the single PCs. By Day 5, 15 of 16 non-white-cell reduced pools had total levels of Staphylococcus epidermidis bacteria approximately five times those in the paired single PCs. Greater total bacteria levels in pooled units than in single units generally occurred when bacteria in pools reached the stationary phase of growth (when bacteria concentration became constant), and they were well correlated with the sixfold volume of pooled units. White cell reduction did not substantially affect the time required to attain stationary phase. CONCLUSION: The potential during storage for greater total bacteria levels in pools than in single PCs is a consequence of the greater volume of the pool.     

胰腺干细胞在糖尿病治疗中的应用

目的:本文就分离克隆胰腺干细胞,并将其定向诱导分化为功能性胰岛移植治疗糖尿病的研究作一综述。资料来源:应用计算机检索CBM和PubMed数据库1978-01/2006-12胰腺干细胞或胰岛干细胞移植治疗糖尿病的文章,检索词为"islet stem cell,pancreatic stem cell,diabetes mellitus,胰腺干细胞,胰岛干细胞,糖尿病"。资料选择:选择胰腺干细胞或胰岛干细胞移植治疗糖尿病的文章,排除重复研究。资料提炼:检索到CBM数据库中胰腺干细胞移植治疗糖尿病文章19篇,胰岛干细胞移植治疗糖尿病文章20篇;PubMed数据库中胰腺干细胞移植治疗糖尿病文章305篇。共纳入41篇。资料综合:糖尿病的治疗方法主要包括药物治疗、胰岛素注射、胰腺器官移植和胰岛细胞移植。胰腺器官移植和胰岛移植是治疗糖尿病的有效方法。由于缺乏完全合适的供体,胰腺器官移植的临床应用受到限制。与胰腺器官移植相比,胰岛细胞移植无需麻醉和剖腹,减小了对移植受体的损伤,降低了风险性。结论:体外分离、克隆人类胰腺干细胞,并定向诱导其分化为功能性胰岛移植治疗糖尿病,是解决胰岛供体短缺的有效途径,但是还没有人胰腺干细胞体外诱导胰岛移植治疗人类糖尿病的报道。     

Predicting survival in AIDS: refining the model

We tested the validity of a previously-published AIDS staging system by examining AIDS-defining diseases (ADDs) and CD4 counts as prognostic factors for survival of the 248 AIDS patients in the Edinburgh City Hospital Cohort, of whom 56% were injecting drug-users (IDUs). Cox regression was used to model the proportionality of risk of death as the CD4 count declined and more ADDs were experienced, and dependence upon post-AIDS treatment. Using the system of Mocroft et al. (Lancet 1995; 346:12-17) to grade severity, our data were well enough modelled, but we suggest: (i) regrading of HIV dementia (RR 3.9, 95% CI 2.5-6.0), mainly attributed to the drug users, to a very severe ADD; (ii) reduction in risk from zidovudine (RR 0.7, 95% CI 0.5-1.0) during AIDS follow-up for patients starting treatment at or after AIDS diagnosis; (iii) improved management of first mild ADDs (from 1987-89 to 1994-95: 40% reduction in IDUs appearing with mild index diseases, and an approximate three-fold reduction in risk associated with a mild ADD). This study supports previous findings on the significance of ADDs and lowest CD4 count in predicting the lifetime of AIDS patients.      

Recruiting blood donors into a local bone marrow donor registry

To date, most persons joining bone marrow donor registries have been recruited from platelet-pheresis panels. The potential of recruiting regular blood donors into bone marrow donor registry (BMDR) was explored. It was found that, with minimal effort, 6.2 percent of the age-eligible blood donors were recruited. A distinguishing feature of those who joined the BMDR was a history of frequent blood donations. Although local media attention had a major impact on recruitment, even those joining as a result of the publicity usually were regular blood donors. This program has the potential to recruit nearly 8000 volunteers from 120,000 regular blood donors over an 18-month period.     

CYCLICAL ETIDRONATE INCREASES LUMBAR SPINE BONE DENSITY IN PATIENTS ON LONG-TERM GLUCOCORTICOSTEROID THERAPY

To determine whether cyclical etidronate modifies bone density in patients on chronic glucocorticosteroid therapy, annual bone density measurements were performed on 55 patients receiving glucocorticosteroids who were randomised to either continuous calcium supplementation or cyclical etidronate plus calcium supplementation in this secondary prevention study. Median L1-L4 lumbar spine bone density decreased by 0.7% in the calcium treated group after one year but increased by 3.1% in the group treated by calcium and etidronate (p=0.00116). Median L1-L4 bone density decreased by 2.8% from baseline after two years in the calcium treated group but increased by 4.7% from baseline In the group treated by calcium and etidronate (p=0.04). There were no significant effects of treatment on femoral neck density. Cyclical etidronate and calcium increased lumbar spine bone density in patients established on prednisolone treatment over a two-year period but had no effect on femoral density.     

Survival of Borrelia burgdorferi in blood products

The incidence of Lyme disease is rapidly increasing in the United States. To assess the potential of transmission of the disease through blood transfusion, we studied the survival of Borrelia burgdorferi in blood products under blood bank storage conditions. Two units of whole blood, separated into red cells (RBCs), fresh-frozen plasma (FFP), and platelet concentrates (PCs), were inoculated with B. burgdorferi (strain B31) in concentrations of approximately 3000 organisms per mL of RBCs and FFP and 200 organisms per mL of PCs. Products were then stored under blood banking conditions and sampled at several storage times. The viability of the spirochete in blood components was determined by darkfield microscopic examination of cultures in modified Kelly's medium. The organism was shown to survive in RBCs (4 degrees C) and FFP (below -18 degrees C) for 45 days and in PCs (20-24 degrees C) for 6 days. The results of this study do not exclude the possibility of transmission of Lyme disease through blood transfusion.     

Diagnosis and treatment of status epilepticus on a neurological intensive care unit

Status epilepticus refractory to first-line therapy is associated with a high morbidity and mortality. Correct diagnosis and adequate treatment of this condition require electrographic monitoring and anaesthetic facilities available in specialist intensive care units (ICUs). We carried out an audit of 26 patients admitted to a neurological ICU with a diagnosis of status epilepticus, to identify deficiencies in diagnosis and management prior to transfer to the ICU, and examine the effectiveness of ICU management. Or transfer, only 14 (54%) were in status epilepticus; six were in drug-induced coma or were encephalopathic, and six had pseudostatus epilepticus, of whom four had been intubated. The commonest treatments prior to transfer were benzodiazepines, chlormethiazole and phenytoin; the loading dose of phenytoin was adequate in at least 7/16 cases. All those in status epilepticus on transfer had their seizures successfully controlled, but ten required general anaesthesia with thiopentone, propofol, ketamine or midazolam. Two died--one had a severe encephalitis and the other had had a cardiac arrest prior to treatment. This study highlights deficiencies in the initial diagnosis and management of status epilepticus, the role of specialist neurological intensive care, and the importance of early referral.