Hemolytic warm IgM autoagglutinins in autoimmune hemolytic anemia

The authors report a patient with fulminant autoimmune hemolytic anemia due to a rare warm IgM autoagglutinin more reactive at 37 degrees C than at lower temperatures and secondary to systemic lupus erythematosis. The patient's clinical course and the serologic and immunochemical characteristics of the antibody are described, including the possibility that transfusions of small amounts of incompatible red cells may have contributed to the hemolysis. The consequences of using the initial serologic test results as the basis for therapy are discussed.     

White cell depletion of red cell and pooled random-donor platelet concentrates by filtration and residual lymphocyte subset analysis

This study comparing the relative white cell (WBC)-depleting efficiency of single and double filtration used two filters and new, sensitive, and reliable methods for performing WBC counts on WBC-depleted blood products. A single filtration of red cell (RBC) concentrates with a cotton-wool filter reduced WBC content by 98.64 percent, but the range of residual WBCs was wide, and many filtered units still contained more than the theoretical immunizing dose of 5 to 10 x 10(6) WBCs. A second filtration, however, always produced RBC units that had less than 5 x 10(6) WBCs. Although the degree of WBC depletion observed after a single filtration of a 6-unit pool of random-donor platelet concentrates was greater with a polyester filter than with the cotton-wool filter (98.92 vs. 98.14% reduction, respectively, when mean prefiltration WBC count was less than 600 x 10(6], in both cases, 25 percent of filtered products still contained greater than 5 x 10(6) WBCs; a second filtration (with the cotton-wool filter), however, produced units that were always below the immunizing dose. All double-filtered platelet concentrates had less than 10(6), and one-half had less than 10(4) residual WBCs. Platelet loss was similar with both filters (+/- 16% loss with one filtration). The effectiveness of the filters in producing products that were WBC-depleted below the immunizing dose was dependent on the prefiltration WBC content (but not on the age of the units), and it may be worthwhile to employ methods to ensure that total prefiltration WBC count of the product is less than 400 x 10(6).(ABSTRACT TRUNCATED AT 250 WORDS)     

Infusible platelet membrane microvesicles: a potential transfusion substitute for platelets

BACKGROUND: Several substitutes for intact, viable platelets have been used for transfusion, both to people and in animal models, with varied success. Infusible platelet membrane (IPM) is prepared from human platelets. IPM retains the glycoprotein (GP)lb receptor and has platelet factor 3 activity (procoagulant activity). However, factor V, serotonin, a cytoplasmic marker enzyme (purine nucleotide phosphorylase), GPIIb/IIIa complex, and HLA class I and II antigens are all absent in IPM. STUDY DESIGN AND METHODS: IPM is prepared from outdated platelets. The platelets were disrupted by freezing and thawing; they were washed and heated to inactivate possible viral contaminants, and then the sonicated membrane microvesicle fraction was separated and lyophilized. The hemostatic activity of IPM was measured by its ability to reduce the prolonged bleeding time in thrombocytopenic rabbits. RESULTS: Administration of IPM at a dose of 2 mg per kg results in a substantial reduction in the bleeding time. In a series of 23 experiments, a median preinjection bleeding time of 15 minutes was reduced to 6 minutes within 4 hours after IPM administration. Administration of IPM did show a mild enhancement in the thrombogenicity index, as measured in the Wessler rabbit model. This enhancement is, however, not significant, as a thrombogenicity index value of up to 0.6 is clinically acceptable. CONCLUSION: IPM may have clinical potential as a substitute for platelets in the treatment of bleeding due to thrombocytopenia.     

经冠状动脉移植自体骨髓单个核细胞和间充质干细胞对急性心肌梗死模型心功能的改善

目的:为保护濒死心肌提供机会窗口,对比观察经冠脉移植自体骨髓单个核细胞或间充质干细胞后,实验性急性心肌梗死动物心功能变化及心肌组织核转录因子кB、心肌细胞凋亡情况。方法:实验于2005-03/2006-11在河北省人民医院实验中心完成。选用24只雄性冀中白猪,随机数字表法分为4组:正常对照组、模型组、单个核细胞组、间充质干细胞组,6只/组。①24只猪均以盐酸氯胺酮200mg臀部肌肉注射麻醉后,分别于各自右侧股骨抽取骨髓20mL,采用Fercoll法分离获得骨髓单个核细胞,加入胶体金溶液,培养12～16h待用。分离过程中取出含有骨髓单个核细胞成分的细胞层,常规培养传代,每3d换液1次,贴壁生长细胞即为骨髓间充质干细胞,加入胶体金溶液,培养24h待用。②除正常对照组外,其余各组均经导管球囊封闭第一对角支以远的前降支,复制猪急性心肌梗死模型。单个核细胞组、间充质干细胞组均于造模后立即开通前降支,分别经球囊注入预先分离的骨髓单个核细胞6×108个、间充质干细胞6×108个。模型组造模后于梗死1h开通前降支,经球囊注入磷酸盐缓冲液10mL。③各组分别于术前及术后4周经心脏超声检测心功能,取材行病理学检查、心肌组织核转录因子кB的免疫组织化学检测及心肌细胞凋亡检测。结果:24只雄性白猪均进入结果分析。①心功能变化:术前各组左心室收缩末内径、左心室舒张末内径、左心室射血分数、短轴缩短率基本相似。移植术后4周,正常对照组、单个核细胞组、间充质干细胞组左心室舒张末内径均明显低于模型组(F=4.68,P=0.01),左心室射血分数及短轴缩短率均明显高于模型组(F=5.14,P=0.01;F=3.32,P=0.04),各组左心室收缩末内径差异无显著性意义(F=1.64,P=0.21)。②心肌组织病理学改变:电镜下单个核细胞组、间充质干细胞组在梗死边缘区可见有胶体金颗粒的不成熟的心肌细胞,胞质中散在肌丝结构,肌丝排列紊乱不规则。③心肌组织核转录因子кB阳性率表达:与模型组比较,单个核细胞组、间充质干细胞组的梗死边缘区核转录因子кB阳性率明显降低(F=25.59,P=0.0001);正常心肌区核转录因子кB阳性率亦明显降低(F=18.20,P=0.0001)。④心肌细胞凋亡检测结果:与模型组比较,单个核细胞组、间充质干细胞组在心肌梗死区细胞凋亡率均明显降低(F=6.63,P=0.0027),梗死边缘区细胞凋亡率亦明显降低(F=36.07,P=0.0001)。正常心肌区单个核细胞组细胞凋亡率与模型组基本相似(F=9.69,P=0.004),但间充质干细胞组有所降低。⑤心功能与心肌细胞凋亡及心肌组织NF-кB的相关性:急性心肌梗死4周时,左心室射血分数与心肌细胞凋亡、心肌组织核转录因子кB均呈负相关(r=0.613,P=0.001;r=-0.437,P=0.033)。心肌细胞凋亡与心肌组织核转录因子кB呈正相关(r=0.672,P=0.002)。结论:经冠脉移植骨髓单个核细胞和间充质干细胞均可改善实验性急性心肌梗死动物的心功能,与梗死边缘区核转录因子кB表达降低及心肌细胞凋亡减少有关。骨髓单个核细胞移植的促血管增生作用优于间充质干细胞移植。     

Aging in Fragile X Premutation Carriers

It is now recognized that FMR1 premutation carriers (PC) are at risk to develop a range of neurological, psychiatric, and immune-mediated disorders during adulthood. There are conflicting findings regarding the incidence of hypertension, hypothyroidism, diabetes, and cancer in these patients that warrant further study. A retrospective controlled study was performed in a convenience sample of 248 controls (130 men, 118 women) and 397 FMR1 PC with and without fragile X-associated tremor ataxia syndrome (FXTAS) (176 men, 221 women); all participants were at least 45 years old (men: mean 62.4, SD 9.5; women: mean 62.8, SD 9.9; p?=?0.63). Memory and cognitive assessments (Wechsler Adult Intelligence Scale (WAIS-III), Wechsler Memory Scale (WMS-III)) and molecular testing (CGG repeats and FMR1-mRNA levels) were performed. Additional data included body mass index (BMI), cholesterol levels, blood pressure, hemoglobin A1c (HbA1c) levels, and medical history. A higher percentage of PC subjects self-reported having a diagnosis of hypertension (50.0 vs. 35.0 %, p?=?0.006) and thyroid problems (20.4 vs. 10.0 %, p?=?0.012) than control subjects. When comparing controls versus PC with FXTAS, the association was higher for diabetes (p?=?0.043); however, the effect was not significant after adjusting for demographic predictors. Blood pressure, blood glucose levels, HbA1c, and BMI values were not significantly different between the two groups. The PC with FXTAS group performed consistently lower in neuropsychological testing compared with the PC without FXTAS group, but the differences were very small for all but the WAIS full-scale IQ. Based on these findings, it appears that the risk for hypertension, thyroid problems, and diabetes may be more frequent in PC with FXTAS, which will require verification in future studies.     

Developmental profiles of infants with an <Emphasis Type="Italic">FMR1</Emphasis> premutation

Background

Emerging evidence suggests that a subset of FMR1 premutation carriers is at an increased risk for cognitive, emotional, and medical conditions. However, because the premutation is rarely diagnosed at birth, the early developmental trajectories of children with a premutation are not known.

Methods

This exploratory study examined the cognitive, communication, and social-behavioral profiles of 26 infants with a premutation who were identified through participation in a newborn screening for fragile X syndrome pilot study. In this study, families whose newborn screened positive for an FMR1 premutation were invited to participate in a longitudinal study of early development. Twenty-six infants with the premutation and 21 matched, screen-negative comparison babies were assessed using validated standardized measures at 6-month intervals starting as young as 3 months of age. The babies were assessed up to seven times over a 4-year period.

Results

The premutation group was not statistically different from the comparison group on measures of cognitive development, adaptive behavior, temperament, or overall communication. However, the babies with the premutation had a significantly different developmental trajectory on measures of nonverbal communication and hyperresponsivity to sensory experiences. They also were significantly more hyporesponsive at all ages than the comparison group. Cytosine-guanine-guanine repeat length was linearly associated with overall cognitive development.

Conclusions

These results suggest that infants with a premutation may present with subtle developmental differences as young as 12 months of age that may be early markers of later anxiety, social deficits, or other challenges thought to be experienced by a subset of carriers.

     

Application of biosafety principles in blood establishments

In light of increasing public and employee concern over potential infectious hazards associated with blood and other body fluids, several government agencies (the Food and Drug Administration, the Centers for Disease Control, the Occupational Safety and Health Administration, the Environmental Protection Agency, the Health Care Financing Administration and the National Heart, Lung and Blood Institute) cosponsored a Biosafety Workshop in April 1988. The objective of the workshop was to identify appropriate biosafety practices and standard control procedures to protect workers involved in the collection, storage, and transportation of human blood donations with the least possible disruption of the nation's blood supply. Speakers focused on human immunodeficiency virus (HIV) and hepatitis B virus (HBV); however, the safety principles discussed were considered equally applicable to other known (e.g., non-A, non-B hepatitis and human T-lymphotropic virus type I (HTLV-1) blood-transmitted infections. The resulting consensus included the need for blood establishments to develop and apply thoughtful biosafety programs to address staff training, accident prevention, HBV vaccination, handling spills, managing contaminated waste and transporting blood specimens. There was lack of agreement, however, on the usefulness of gloves during the phlebotomy of healthy blood donors.     

The accuracy of quantitative parameters in 99mTc‐MAG3 dynamic renography: a national audit based on virtual image data

Assessment of image analysis methods and computer software used in ^99mTc‐MAG3 dynamic renography is important to ensure reliable study results and ultimately the best possible care for patients. In this work, we present a national multicentre study of the quantification accuracy in ^99mTc‐MAG3 renography, utilizing virtual dynamic scintigraphic data obtained by Monte Carlo‐simulated scintillation camera imaging of digital phantoms with time‐varying activity distributions. Three digital phantom studies were distributed to the participating departments, and quantitative evaluation was performed with standard clinical software according to local routines. The differential renal function (DRF) and time to maximum renal activity (T_max) were reported by 21 of the 28 Swedish departments performing ^99mTc‐MAG3 studies as of 2012. The reported DRF estimates showed a significantly lower precision for the phantom with impaired renal uptake than for the phantom with normal uptake. The T_max estimates showed a similar trend, but the difference was only significant for the right kidney. There was a significant bias in the measured DRF for all phantoms caused by different positions of the left and right kidney in the anterior–posterior direction. In conclusion, this study shows that virtual scintigraphic studies are applicable for quality assurance and that there is a considerable uncertainty associated with standard quantitative parameters in dynamic ^99mTc‐MAG3 renography, especially for patients with impaired renal function.     

CGG-repeat length threshold for FMR1 RNA pathogenesis in a cellular model for FXTAS

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder that affects carriers of premutation alleles (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene. The presence of elevated levels of expanded mRNA found in premutation carriers is believed to be the basis for the pathogenesis in FXTAS, but the exact mechanisms by which the mRNA causes toxicity are not known. In particular, it is not clear whether there is a threshold for a CGG-repeat number below which no cellular dysregulation occurs, or whether toxicity depends on mRNA concentration. We have developed a doxycycline-inducible episomal system that allows us to study separately the effects of CGG-repeat number and mRNA concentration (at fixed CGG-repeat length) in neuroblastoma-derived SK cells. Our findings show that there is a CGG-repeat size threshold for toxicity that lies between 62 and 95 CGG repeats. Interestingly, for repeat sizes of 95 CGG and above, there is a clear negative correlation between mRNA concentration and cell viability. Taken together, our results provide evidence for an RNA-toxicity model with primary dependence on CGG-repeat size and secondary dependence on mRNA concentration, thus formally ruling out any simple titration model that operates in the absence of either protein-binding cooperativity or some form of length-dependent RNA structural transition.