Arteriovenous malformations of the extremities: MR imaging

Eight patients with angiographically proved arteriovenous malformations (AVMs) of the extremities (seven congenital, one posttraumatic) were evaluated with magnetic resonance (MR) imaging using a 0.35-T superconducting system and spin-echo pulse sequences. Congenital AVMs appeared as accumulations of dilated tortuous blood vessels infiltrating the involved muscles. A posttraumatic acquired AVM of the shoulder consisted of a large feeding artery associated with a pseudoaneurysm and a soft-tissue mass. MR imaging allowed precise anatomic localization and provided details concerning the size and extent of the AVMs. The relationship of AVMs to specific muscle groups, bones, and vascular structures could be accurately determined. Although major feeding and draining vessels were identified, the exact arteries and veins supplying and draining the AVM could not be ascertained. Images obtained in the transverse plane consistently yielded the most useful information. MR imaging and angiography may be complementary techniques in the initial evaluation, follow-up, and treatment planning of AVMs of the extremities.     

Inhibition of human lymphocyte reactivity by plasma fibronectin in vitro

The effect of purified human plasma fibronectin (FN) on the reactivity of human lymphocyte-rich mononuclear cells to mitogens and allogeneic cell interactions was studied. Concentrations of FN from 25 to 100 micrograms per 250 microL of culture consistently depressed phytohemagglutinin (PHA) responses. To exert an inhibitory effect, FN must be present within 20 hours after the addition of PHA to cells, and, therefore, it appears to interfere with early events in the transformation process. Increasing the concentration of PHA failed to reduce the inhibitory effect of FN, which suggests that the depressed response was not the result of FN-PHA complex formation, which would reduce the amount of mitogen available for stimulation. This possibility was supported by the finding that FN also inhibited the mixed lymphocyte response (MLR), in a reaction that was not dependent on the activity of soluble antigen or mitogen. In contrast, the stimulation of lymphocytes to undergo transformation that is induced by the nonlectin mitogen, sodium periodate, was unaffected by FN. Periodate-treated cells are, however, already stimulated to undergo transformation, prior to their exposure to FN. FN did not interfere with the activity of interleukin-2, nor did it indirectly regulate lymphocyte responses by modifying the production and/or effect of humoral regulatory factors released from the adherent accessory cells (macrophages). These studies show that FN is a potent immunosuppressive agent in vitro.     

Influence of fibronectin-containing blood products on lymphocyte reactivity

Two fibronectin (FN)-containing blood products, human peripheral blood plasma and cryoprecipitate, were examined for their effect on mitogen-induced lymphocyte transformation in vitro. Responses of human peripheral blood lymphocytes to phytohemagglutinin (PHA) were depressed in the presence of a plasma concentration above that required for maximum DNA synthesis, and this concentration must be present in cultures prior to lymphocyte activation. The removal from the plasma of heparin-induced cryoprecipitate, a complex consisting of FN, heparin, and fibrinogen, resulted in a significant reduction in the inhibitory effect of the plasma on the PHA response. Plasma specifically depleted of FN by affinity chromatography on gelatin-agarose beads was 32 percent less inhibitory to the PHA-induced stimulation of cells than untreated plasma; the remaining inhibitory activity in the FN-depleted plasma samples was attributed to the presence of other normal immunosuppressive factors. The inhibitory capacity of FN in plasma was similar to that obtained with purified FN alone, which indicates that, unlike that of other known plasma inhibitors, the immunosuppressive activity of FN was not altered by the presence of other components of plasma. Cryoprecipitate used in the treatment of hemophilia contains high levels of FN, and, as anticipated, PHA-induced lymphocyte transformation was markedly depressed in the presence of solubilized cryoprecipitate. The contribution of FN to the T-cell abnormalities in patients chronically receiving cryoprecipitate and/or factor VIII concentrates derived from cryoprecipitate warrants further investigation.     

个性化颅骨成形术中植入材料类型与颅骨缺损面积的关系

目的：分析个性化颅骨成形术中,植入材料类型与颅骨缺损面积的关系。 方法：选择解放军总医院第二附属医院神经外科2002-03/2005-01和河北省三河市医院神经外科2003-09/2005-04收治的资料齐全的计算机辅助设计颅骨成形术患者75例,分为嵌入性材料（骨水泥、硅橡胶）组40例,根据颅骨缺损面积又分为大面积（≥36cm2）组17例和小面积（〈36cm2）组23例;覆盖性材料（钛网）组35例,大面积组14例和小面积组21例。采用头颅CT超薄扫描（层厚1.5mm）,三维重建,模拟缺损颅骨补片,应用激光快速成形技术,制作缺损颅骨及颅骨补片模型,患者认可后,根据患者的病情应用硅橡胶、骨水泥、钛网作为植入材料,进行手术植入。术后1周观察并发症：头痛、积液、松动。 结果：75例患者的补片与颅骨完整适配,塑形满意,术中无需修整,平均手术时间45min,83%（63/75）患者感到基本或完全恢复了原有容貌。手术并发症：嵌入性材料组头痛4例,积液10例,松动2例,共16例,其中大面积组13例,小面积组3例;覆盖性材料组头痛1例,积液2例,松动0例,共3例次,其中大面积组2例,小面积组1例。应用精确概率分析,两材料组之间手术并发症差异显著,两材料组颅骨缺损面积之间手术并发症差异显著,嵌入性材料大面积组与覆盖性材料大面积组之间手术并发症差异显著,嵌入性材料小面积组与覆盖性材料小面积组之间手术并发症无显著性差异。 结论：个性化设计的颅骨修补材料,能够最大限度的恢复患者外形,缩短手术时间,大面积的颅骨缺损应用钛网修补,小面积的应用钛网和嵌入性材料修补。根据患者颅骨缺损面积,选择不同植入材料,可以提高手术疗效,减少术后并发症。     

Choosing event‐driven and daily HIV pre‐exposure prophylaxis – data from two European PrEP demonstration projects among men who have sex with men

IntroductionDaily and event‐driven PrEP are both efficacious in reducing the risk for HIV infection. However, the practice of event‐driven PrEP (edPrEP) is less well studied, in particular when provided as an alternative to daily PrEP. We studied regimen preferences and switches, and sexually transmitted infection (STI) incidence.MethodsWe analysed pooled data from two prospective cohort studies among MSM: Be‐PrEP‐ared, Belgium and AMPrEP, the Netherlands. In both projects, participants could choose between daily and edPrEP at three‐monthly study visits, when they were also screened for sexually transmitted infections including hepatitis C (HCV). We assessed the proportion choosing each regimen, and the determinants of choosing edPrEP at baseline. Additionally, we compared the incidence rates (IRs) of HCV, syphilis and chlamydia or gonorrhoea between regimens using Poisson regression. The study period was from 3 August 2015 until 24 September 2018.Results and discussionWe included 571 MSM, of whom 148 (25.9%) chose edPrEP at baseline. 31.7% of participants switched regimen at least once. After 28 months, 23.5% used edPrEP. Older participants (adjusted odds ratio (aOR) = 1.38 per 10 years, 95% confidence interval (CI) = 1.15 to 1.64) and those unemployed (aOR = 1.68, 95% CI = 1.03 to 1.75) were more likely to initially choose edPrEP. IR of HCV and syphilis did not differ between regimens, but the IR of chlamydia/gonorrhoea was higher among daily users (adjusted incidence rate ratio = 1.61, 95% CI = 1.35 to 1.94).ConclusionsA quarter of participants chose edPrEP at baseline and at 28 months this proportion was similar. Although the IR of HCV and syphilis were similar in the two regimens, the lower incidence of chlamydia and gonorrhoea among edPrEP users may suggest that less frequent STI testing of this group could be considered.     

Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: a Pediatric Investigators Collaborative Network on Infections in Canada Study

OBJECTIVE: To determine nosocomial transmission of respiratory syncytial virus (RSV) in Canadian pediatric hospitals, outcomes associated with nosocomial disease, and infection control practices. DESIGN: A prospective cohort study in the 1992 to 1994 winter respiratory seasons. SETTING: Nine Canadian pediatric university-affiliated hospitals. PARTICIPANTS: Hospitalized children with symptoms of lower respiratory tract infection (at least one of cough, wheezing, dyspnea, tachypnea, and apnea) and RSV antigen identified in a nasopharyngeal aspirate. RESULTS: Of 1516 children, 91 (6%) had nosocomial RSV (NRSV), defined as symptoms of lower respiratory tract infection and RSV antigen beginning >72 hours after admission. The nosocomial ratio (NRSV/[com-munity-acquired RSV {CARSV})] + NRSV) varied by site from 2.8% to 13%. The median length of stay attributable to RSV for community-acquired illness was 5 days, but 10 days for nosocomial illness. Four children with NRSV (4. 4%) died within 2 weeks of infection, compared with 6 (0.42%) with CARSV (relative risk = 10.4, 95% confidence interval: 3.0, 36.4). All sites isolated RSV-positive patients in single rooms or cohorted them. In a multivariate model, no particular isolation policy was associated with decreased nosocomial ratio, but gowning to enter the room was associated with increased risk of RSV transmission (incidence rate ratio 2.81; confidence interval: 1.65, 4.77). CONCLUSIONS: RSV transmission risk in Canadian pediatric hospitals is generally low. Although use of barrier methods varies, all sites cohort or isolate RSV-positive patients in single rooms. Children with risk factors for severe disease who acquire infection nosocomially have prolonged stays and excess mortality.     

Prothrombin complex concentrate (Beriplex P/N) in severe bleeding: experience in a large tertiary hospital

Introduction

Major blood loss can often be life-threatening and is most commonly encountered in the settings of surgery and trauma. Patients receiving anticoagulant therapy are also at increased risk of bleeding. We investigated the use of a prothrombin complex concentrate (PCC; Beriplex P/N, CSL Behring, Marburg, Germany) to treat severe bleeding in a variety of settings: cardiac surgery, warfarin therapy and other surgery.

Methods

Thirty consecutive patients who had received PCC were identified from blood transfusion records. For cardiac surgery and warfarin reversal, PCC was administered in accordance with hospital protocols. PCC was administered to cardiac and other surgical patients responding poorly to recognized blood products, whereas it was administered first-line to patients with life-threatening bleeds and requiring warfarin reversal, in accordance with British Committee for Standards in Haematology guidelines. We conducted a retrospective analysis of patient records in order to ascertain PCC dose, use of other blood products and response to PCC (clotting screen results before and after PCC administration, haemostasis achievement, and survival).

Results

Six patients (20%) were excluded because of inadequate documentation (n = 5) or acquired haemophilia (n = 1). Therefore, 24 patients were included in the analysis: coronary artery bypass graft (n = 5), mitral/aortic valve replacement (n = 2), other surgery (n = 9) and warfarin reversal (n = 8). Most patients (83.3%) received no more than 1500 IU of Beriplex P/N 500. Considerable reduction in administration of other blood products was seen during the 24 hours after PCC administration. Partial or complete haemostasis was achieved in 14 out of 18 cases (77.8%). In total, 12 out of 24 patients (50%) died during the study; two-thirds of the deaths were considered unrelated to bleeding. No thrombotic complications or adverse drug reactions were observed.

Conclusion

This study emphasizes the value of PCC in reversing the effects of oral anticoagulant therapy in bleeding patients. It also demonstrates the potential value of PCC in controlling bleeding in patients undergoing cardiac and other surgical procedures. The use of PCC in bleeding patients without hereditary or anticoagulation-related coagulopathy is novel, and further investigation is warranted. In the future, it may be possible to use PCC as a substitute for fresh frozen plasma in this setting; adequate documentation is crucial for all blood products.     

Diagnosis of advanced fibrosis in HIV and hepatitis C virus-coinfected patients via a new noninvasive index: the HGM-3 index

Background

Noninvasive tests are increasingly being used for the assessment of liver fibrosis. We aimed to develop a serum index for the identification of advanced fibrosis (F≥3) in HIV/hepatitis C virus (HCV)‐coinfected patients.

Methods

We carried out a cross‐sectional study on a group of 195 patients comprised of an estimation group (EG; n=127) and a validation group (VG; n=68) who all underwent liver biopsy and had not received previous interferon therapy. Liver fibrosis was estimated using the METAVIR score. We developed a new serum index (HGM‐3) dependent on levels of platelets, alkaline phosphatase, hepatic growth factor, tissue inhibitor of metalloproteinase‐1 and hyaluronic acid.

Results

In the EG, the area under the receiver operating characteristic curve (AUC‐ROC) of HGM‐3 for identification of F≥3 was 0.939 [95% confidence interval (CI) 0.899, 0.979] which was significantly higher than the AUC‐ROC of the HGM‐2, FIB‐4, aspartate aminotransferase to platelet ratio (APRI) and Forns' indexes. With HGM‐3 <0.135 for F<3, 57 patients were correctly identified and two patients were misclassified. We found the presence of F<3 with 96.6% certainty. The negative likelihood ratio (LR) was <0.1 and the diagnostic odds ratio (DOR) was >40. With HGM‐3 >0.570 in the EG for F≥3, 31 patients were correctly identified, and five patients were misclassified. We found the presence of F≥3 with 86.1% certainty. The positive LR was >12 and the DOR was >40. For the VG, the diagnostic accuracy values were similar to the values for the EG.

Conclusions

HGM‐3 appears to be an accurate noninvasive method for the diagnosis of bridging fibrosis and cirrhosis in HIV/HCV‐coinfected patients.