Molecular biology in transfusion medicine: current applications and future practice

Alloantibodies to blood group antigens are produced because there are differences between the blood group antigens on recipient and donor (or mother and fetus) red blood cells. Historically and currently, blood group antibodies and antigens are detected by hemagglutination, which can require considerable skill. Over the past 2 decades, there has been an astounding pace of growth in the field of molecular biology techniques and even more recently in the understanding of the basis of many blood group antigens and phenotypes. Thus, we are now able to consider identification of blood group antigens in genetic terms and identification of blood group antibodies using molecular approaches. Indeed, this knowledge is being applied to help resolve some long-standing clinical problems that cannot be resolved by classic hemagglutination. This article reviews our current knowledge of molecular approaches for identifying blood group antigens and antibodies as applied to transfusion medicine.     

Nutritional supplementation of very old people at hospital discharge increases muscle strength: a randomised controlled trial

BACKGROUND: Undernutrition is common in older people admitted to hospital, but little is known about how nutritional state changes after discharge. OBJECTIVE: This randomised controlled trial was designed to examine the effect of oral nutritional supplementation of undernourished very old people prepared to take supplements after hospital discharge following acute illness. METHODS: Participants aged>or=75 years with a BMIor=5% during an acute hospital stay were allocated at random to either oral nutritional supplementation for 8 weeks from hospital discharge or to usual care. Primary outcome was change in weight, secondary outcomes were handgrip strength and anthropometry. RESULTS: Of 198 patients eligible to participate, 136 patients (mean age 85 years) were randomised and 76/136 (56%) completed the study. Twenty percent (13/66) of the intervention group withdrew after only 2 weeks, citing intolerance of the supplements. Using intention-to-treat analysis, body weight increased by a mean of 1.6 and 2.2% in the control and intervention groups, respectively, but this between-group difference was not significant (p = 0.188). However, handgrip strength increased more (p=0.055) in the intervention group (13.9%) than in the control group (7.2%). CONCLUSIONS: Oral nutritional supplementation was associated with a greater increase in handgrip strength than in non-supplemented controls and this observation merits further study.     

A conserved HLA B13-restricted cytotoxic T lymphocyte epitope in Nef is a dominant epitope in HLA B13-positive HIV-1-infected patients

We report on the first HLA B13-restricted minimal cytotoxic T lymphocyte (CTL) epitope RQDILDLWI (RI9, amino acids 106-114 in HIV-1 Nef). In most patients the frequency of RI9-specific CTL exceeded the number of CTL against other epitopes, indicating that RI9 is a dominant epitope in HLA B13-positive patients. Targeting this conserved Nef epitope may be an important factor for the published association of HLA B13 with a favourable course of HIV-1 infection.     

What is the value of home blood pressure measurement in patients with mild hypertension?

To investigate the value of home blood pressure (BP) measurements, the BP was recorded daily by the patient at home and compared with recordings in the physician's office and with a 24-hour BP recording taken with a noninvasive ambulatory BP recorder in a group of 93 patients with mild untreated hypertension. Office BPs (mean 148/94 mm Hg) were higher than either home (138/89 mm Hg) or average 24-hour BPs (131/89 mm Hg). For systolic BP, home and office measurements gave similar correlations with 24-hour BP (0.67 and 0.55). For diastolic BP, however, home readings were lower and more accurate (0.76 vs 0.36). Thus, our findings indicate that home readings reflect the overall level of BP more reliably than office readings, and if due consideration is given to the fact that they are usually lower than office readings, they may be used as an alternative and cost-effective means of evaluating patients with mild hypertension.     

Precedents for meaningful recovery during treatment in a medical intensive care unit. Outcome in patients with hematologic malignancy

The medical records of 77 patients with hematologic malignancy who were admitted to a medical intensive care unit over a 21-month period were reviewed. The overall hospital mortality rate was 80 percent. Sixteen patients (21 percent) were discharged from the intensive care unit but eventually died in the hospital. The cause of death was the result of a new problem in only three of these 16 patients. Hypotension (shock) and acute respiratory failure were the reasons prompting admission to the intensive care unit in 75 percent, but death in the intensive care unit was almost always the result of intractable hypotension rather than refractory hypoxemia. Only four of 52 patients who required mechanical ventilation left the hospital. In all four, the duration of ventilatory support was less than five days and the cause of respiratory failure was noninfectious in nature. Factors such as congestive heart failure, leukopenia, and abnormalities in mental status modified the hospital course, but did not alter outcome once prolonged mechanical ventilation became necessary. The data suggest that once acute respiratory failure develops in patients with lymphoma or leukemia, presumably as a result of infection, and mechanical ventilation for more than a relatively brief period is required, the prognosis is uniformly grim. Decisions to limit aggressive therapies is subsets of intensive care patients such as these should be aided by data that show a lack of precedent for meaningful recovery.     

Atherosclerotic plaque rupture: local or systemic process?

It is generally established that the unstable plaque is the major cause of acute clinical sequelae of atherosclerosis. Unfortunately, terms indicating lesions prone to plaque instability, such as "vulnerable plaque," and the different phenotypes of unstable plaques, such as plaque rupture, plaque fissuring, intraplaque hemorrhage, and erosion, are often used interchangeably. Moreover, the different phenotypes of the unstable plaque are mostly referred to as plaque rupture. In the first part of this review, we will focus on the definition of true plaque rupture and the definitions of other phenotypes of plaque instability, especially on intraplaque hemorrhage, and discuss the phenotypes of available animal models of plaque instability. The second part of this review will address the pathogenesis of plaque rupture from a local and a systemic perspective. Plaque rupture is thought to occur because of changes in the plaque itself or systemic changes in the patient. Interestingly, contributing factors seem to overlap to a great extent and might even be interrelated. Finally, we will propose an integrative view on the pathogenesis of plaque rupture.     

Peripheral blood lymphocytes express the platelet-type thrombin receptor

Summary. Northern blot analysis of human mononuclear cells indicated that the platelet thrombin receptor may be expressed by lymphocytes. In order to investigate this, we prepared affinity purified rabbit antibodies against the thrombin receptor which bound platelets and blocked thrombin activation. Using flow cytometry on peripheral blood cells, we found that the vast majority of NK cells (CD16/CD56 positive) and a fraction of CD3/CD4 positive T cells expressed the thrombin receptor. B cells, neutrophils and monocytes were negative. These data suggest that potentially thrombin may play a direct role in regulating NK and T cell function.