Lack of clinical significance of "enzyme-only" red cell alloantibodies

In a retrospective study on samples from 10,000 recently transfused patients, 35 samples were found to contain an antibody that reacted with ficin-treated red cells but was not demonstrable by low-ionic- strength saline solution and indirect antiglobulin test (LISS-IAT). In those 35 patients, the specificity of the antibody was such that each patient would have been transfused with antigen-negative blood had the antibody reacted in LISS-IAT. Tests on red cells from the units already transfused showed that 19 patients had among them received, by chance, 32 antigen-positive and 74 antigen-negative units. The remaining 16 patients had among them received 57 units that were, again by chance, all antigen negative. One patient given antigen-positive blood suffered a delayed transfusion reaction; in two others the antibodies became LISS-IAT active after transfusion. However, similar changes to the LISS- IAT-active state were seen with two antibodies of patients given only antigen-negative blood. Also found in the 10,000 patients were 28 clinically insignificant antibodies, 77 sera in which the antibody was too weak to identify, and 216 autoantibodies that reacted only with ficin-treated red cells. These data support a belief, generally held in the United States but not necessarily elsewhere, that the use of protease-treated red cells for routine pretransfusion tests creates far more work than the accrued benefits justify.     

GE Signa Twinspeed 1.5T磁共振肝脏扩散加权成像的技术探讨

目的探讨高场强双梯度磁共振机(GE Signa Twinspeed 1.5T)的肝脏扩散加权成像技术(DWI).方法对20例正常肝脏进行扩散加权成像研究,分别改变重复时间(TR)及扩散敏感系数(b值),测定ADC值、信噪比、图像质量等.结果 b值固定,TR值改变,正常肝组织平均ADC值差异不显著(P>0.05);TR值固定,b值改变,ADC值随b值增大而减小(P<0.05,差异有显著性).b值越大,图像质量越差;b≥800 s/mm2时,图像几乎难以观察.结论 ADC值随b值的增大而减小.行肝脏扩散加权成像时,可适当减小TR值,以缩短扫描时间及患者的屏气时间,减少呼吸运动伪影.     

Effect of ligamentum teres tear on the development of joint instability and articular cartilage damage: an in vivo rabbit study

The contribution of the ligamentum teres to the stabilization of the hip joint and the clinical influence of a compromised ligamentum teres are not well known. This study aimed to investigate joint stability and cartilage damage in a rabbit model by surgically inducing a complete ligamentum teres tear. Twenty adult New Zealand rabbits were used in this study. Rabbits were divided into complete ligamentum teres tear with capsulotomy (n = 9, group I) and capsulotomy only (n = 10, group II) groups. Unilateral surgery was performed on the left hip. Joint instability was assessed by measuring the preoperative and postoperative acetabulofemoral (A-F) distances. Rabbits were euthanized to assess cartilage damage at 24 weeks postoperatively. The median postoperative A-F distance of the operated side in group I [0.68 cm (0.37–1.04 cm)] was larger than that in group II [0.50 cm (0.30–0.65 cm)] (p = 0.041). The median postoperative A-F distance was larger in the operated side [0.68 cm (0.37–1.04 cm)] compared to the nonoperated side [0.45 cm (0.30–0.75 cm)] in group I; it also was larger in the operated side [0.50 cm (0.30–0.65 cm)] compared to the nonoperated side [0.44 cm (0.32–0.67 cm)] in group II, but only group I showed a significant difference (p = 0.016 and 0.395, respectively). Articular cartilage damage was detected at the apex of the femoral head in two rabbits (22.2%) in group I only. Rabbits with a complete ligamentum teres tear showed significant instability at the hip joint and articular cartilage damage in our rabbit model, supporting the potential clinical importance of ligamentum teres as a hip joint stabilizer.     

Heterogeneity of anti-U demonstrable by the use of papain-treated red cells

When red cells (RBCs) are treated with papain, one form of the U antigen, which we have named UPS (U papain-sensitive), is almost completely removed or denatured. A second form, UPR (U papain-resistant), remains unaltered on the treated RBCs. Tests on 42 examples of anti-U showed that two contained only anti-UPS, 19 contained only -UPR, and 21 contained separable -UPS and -UPR. In those sera containing both antibodies, anti-UPR was always the stronger of the two. These findings suggest 1) that UPS is located on the Ss sialoglycoprotein (glycophorin B) at a position distal to a papain-sensitive site or that the cleavage point is within the portion of the SGP that comprises UPS, and 2) that UPR is located between the papain-sensitive site and the RBC membrane. The UPS determinant was not denatured by neuraminidase, L-cysteine, trypsin, ficin, or alpha-chymotrypsin, and it was only partially denatured by pronase. The finding that RBCs treated with para-chloromercuribenzoic acid or para-chloromercuriphenyl sulfonic acid did not react with anti-UPR but did continue to react with anti-UPS suggests that the in situ configuration of UPR, but not UPS, is dependent on the presence of one or more disulfide bonds. RBCs of the S-s-U+(weak) phenotype were shown to carry markedly reduced amounts of both UPS and UPR.     

Recompression of vertebral body after balloon kyphoplasty for osteoporotic vertebral compression fracture

The purpose of this retrospective clinical study was to evaluate the factors that affect recompression of operated vertebrae after percutaneous balloon kyphoplasty (PKP) for osteoporotic vertebral compression fractures (VCFs) and assess their clinical importance. PKP has been used for VCFs with satisfactory results. Several studies about subsequent VCFs adjacent to cemented vertebrae have been reported after PKP. However, the presence and significance of recompression of operated vertebrae have not been adequately described. In total, 80 patients treated with PKP for single thoracolumbar VCFs were reviewed. The follow-up period was at least 1 year. Patients were divided into those without recompression (maintained group, n = 70) and those with recompression (recompressed group, n = 10). Plain roentgenography (preoperative, operative, and last), preoperative BMD, and preoperative MRI were checked. Age, gender, T-score in BMD, duration of symptom, compression rate (CR) of VCF, reduction rate, kyphotic angle (KA), reduction angle, intervertebral cleft (IVC), and non-PMMA-endplate-contact (NPEC) were evaluated. To evaluate the clinical results, we checked the VAS score at each follow-up period. All data were analyzed statistically. The CR for the recompressed group increased significantly after surgery and decreased at the last follow-up (p < 0.05). The last CR was not significantly different from the preoperative CR. The KA showed the same pattern. The preoperative, postoperative, and last VAS scores were significantly different from one another in both groups (p < 0.05). Between the groups, preoperative KA, postoperative KA, last KA, IVC, and NPEC were significantly different (p < 0.05). In particular, last KA, IVC, and NPEC showed highly significant differences (p < 0.001). In a correlation test for the evaluated factors, IVC (r = 0.557) and NPEC (r = 0.496) were the most significant. The presence of IVC and NPEC may play an important role in inducing recompression of treated vertebrae after PKP. Careful observation of patients with these conditions is necessary to prevent deterioration of their clinical course.     

The Importance of Early Carotid Endarterectomy in Symptomatic Patients

INTRODUCTION

Early carotid endarterectomy (CEA) in symptomatic patients may prevent repeat cerebral events. This study investigates the relationship between waiting time for CEA and the incidence of repeat cerebral events prior to surgery in symptomatic patients.

PATIENTS AND METHODS

A prospective database of consecutive patients undergoing CEA between January 2002 and December 2006 was reviewed. Repeat event rates prior to surgery were calculated using Kaplan–Meier analysis and predictive factors identified using Cox regression analysis.

RESULTS

A total of 118 patients underwent CEA for non-disabling stroke, TIA and amaurosis fugax. Repeat cerebral events occurred in 34 of 118 (29%) patients at a median 51 days (range, 2–360 days) after the first event. The estimated risk of repeat events was 2% at 7 days and 9% at 1 month after first event (Kaplan–Meier survival analysis). Age (HR 1.059; 95% CI 1.014–1.106; P = 0.009] was identified as a predictor of repeat events. Patients underwent surgery at median 97 days (range, 7–621 days) after the first event. Eleven of 60 (18%) patients waiting ≤?97 days for surgery and 23 of 58 (40%) patients waiting >?97 days had repeat events. (P = 0.011, chi-squared test).

CONCLUSIONS

Delays in surgery should be reduced in order to minimise repeat cerebral events in patients with symptomatic carotid stenosis, particularly in the elderly population.     

Hepatitis B Immunisation in Health Care Workers

Background

Hepatitis B virus (HBV) infection is an important occupational risk in health care workers (HCW). In spite of HBV vaccine availability in Armed Forces, the high prevalence of HBV infection in HCW continues to be a problem. The study was undertaken to study the HBV vaccine-compliance among HCW.

Methods

A cross-sectional study was conducted at a tertiary care hospital. HCW were requested to fill up the pre set questionnaire to assess the HBV vaccination coverage.

Result

Amongst 254 HCW, only 57.7% were vaccinated against HBV. The vaccine compliance was lowest among housekeeping professionals. The mean age at vaccination was high (30.5 years). Amongst the vaccine non-compliant subjects, 34.3% were above 30 years of age. 32.2% HCW completed primary vaccination after spending more than 10 years in the profession. Accessibility of HBV vaccine, knowledge and perception of HBV risk were important factors in vaccine non-compliance.

Conclusion

Due to low and delayed HBV vaccine-compliance, HCW continue to be at the risk of occupational HBV. Health education highlighting occupational risk of HBV, accessibility of vaccine and mandatory vaccination of HCW is recommended to increase HBV vaccine compliance among HCW.Key Words: Health care workers, Hepatitis B virus, Occupational risk, Hepatitis B vaccine     

Maxillary expansion in cleft lip and palate using Quad helix and rapid palatal expansion screw

Background: Management of patients with cleft lip and palate (CLP) includes orthodontic treatment prior to bone grafting. Palatal expansion is done using slow or rapid palatal expansions (RPE). Controversy still exists regarding choice of expansion appliances used. This study was conducted to find out whether the Quad helix appliance represents a reasonable alternative to using conventional rapid maxillary expansion appliance among cleft lip and palate patients.