Comparison of Diaton transpalpebral tonometer with applanation tonometry in keratoconus

AIM: To investigate the added value of using a Diaton transpalpebral tonometer (DT) to measure IOP in keratoconus. Most type of tonometers use corneal applanation or biomechanical resistance to measure intraocular pressure (IOP); however, these factors can be altered by keratoconus. Specifically, we examined whether DT can detect false-negative low Goldmann applanation tonometry (AT) measurements. METHODS: Patients with keratoconus were recruited from our tertiary academic treatment center. Measurements included AT and DT (in random order) and Scheimpflug imaging. An age- and gender-matched group of control subjects with no history of corneal disease or glaucoma was also recruited. RESULTS: In total, 130 eyes from 66 participants were assessed. In the keratoconus group, mean AT was 11.0 ± 2.6, mean DT 11.2±5.5 (P=0.729), and the two measures were correlated significantly (P=0.006, R=0.323). However, a Bland-Altman plot revealed a wide distribution and poor agreement between both measurements. Previous corneal crosslinking, corneal pachymetry, and Krumeich classification had no effect on measured IOP. CONCLUSION: Measurements obtained using a Diaton tonometer are not affected by corneal biomechanics; however, its poor agreement with Goldmann AT values calls into question the added value of using a Diaton tonometer to measure IOP in keratoconus.     

胶原诱导性关节炎的评定与T细胞受体-热休克蛋白70DNA疫苗的保护作用

目的:纯化制备含有编码T细胞受体(TCR)Vβ5.2/8.2基因片段与结核杆菌热休克蛋白(HSP)70的一段保守序列P111-125的嵌合DNA疫苗,观察其对胶原诱导性关节炎的保护性作用。方法:实验于2006-07/2007-02在首都医科大学免疫学系实验室完成。①实验分组:36只Lewis大鼠随机分为6组,即正常对照组、胶原诱导性关节炎对照组、空质粒组、pTARGET-TCRVβ5.2-HSP70重组质粒治疗组、pTARGET-TCRVβ8.2-HSP70重组质粒治疗组及pTARGET-TCRVβ5.2-HSP70和pTARGET-TCRVβ8.2-HSP70重组质粒联合治疗组,每组6只。②实验方法:大量纯化制备重组DNA疫苗pTARGET-TCRVβ5.2-HSP70、pTARGET-TCRVβ8.2-HSP70和空质粒pTARGET,观察重组DNA疫苗对胶原诱导性关节炎的保护效果,包括关节炎指数评分、Eli-spot法测定脾细胞分泌的干扰素γ和白细胞介素4的水平、ELISA法测定血清中抗Ⅱ型胶原抗体的水平;光镜下观察大鼠后肢足关节的病理学变化。结果:36只Lewis大鼠均进入结果分析。重组DNA疫苗pTARGET-TCRVβ5.2-HSP70和pTARGET-TCRVβ8.2-HSP70对胶原诱导性关节炎有较好的保护性作用,与胶原诱导性关节炎对照组相比,关节炎指数(P<0.05)下降,炎性细胞因子干扰素γ水平(P<0.05)和抗Ⅱ型胶原抗体水平(P<0.01)降低,抑制性细胞因子白细胞介素4水平(P<0.05)升高,病理学改变较轻。且两种重组质粒联合治疗的效果要比单种质粒好。结论:重组DNA疫苗pTARGET-TCRVβ5.2-HSP70和pTARGET-TCRVβ8.2-HSP70能明显减轻胶原诱导性关节炎大鼠的关节炎症状和病理改变,二者联合应用效果更佳。     

Approaches to preventing or reversing platelet alloimmunization using animal models

Animal transfusion models were established to assess treatment programs for preventing or reversing platelet alloimmunization. Five control baboons given weekly transfusions of radiolabeled platelets from a single unrelated donor became immunized after an average of 2.4 +/- 2.1 transfusions. Similarly, 18 of 21 (86%) dogs given up to eight platelet transfusions from a single unrelated donor became immunized after an average of 2.3 +/- 1.7 transfusions. In six of seven baboons, prednisone or antithymocyte globulin alone or in combination effectively delayed platelet alloimmunization. In contrast, only two of 12 (17%) dogs given prednisone or antithymocyte serum (ATS) resisted alloimmunization. Neither splenectomy nor cyclophosphamide prevented alloimmunization in the baboon. In addition, attempts to reduce the immunogenicity of transfused platelets by inactivating the contaminating leukocytes with gamma radiation or by giving leukocyte-poor platelets were of no benefit in dogs. Reversal of platelet alloimmunization was achieved in two of three dogs treated with ATS and procarbazine hydrochloride. However, neither splenectomy, cyclophosphamide, ATS plus prednisone, nor vincristine sulfate produced any improvement. These studies show that the highly immunogenic nature of platelet transfusions in animals makes feasible the study of the prevention and reversal of platelet alloimmunization.     

Lack of evidence of hepatitis C infection in 290 blood component recipients, demonstrated by several single-antigen research immunoassays

BACKGROUND: A group of 290 transfusion recipients enrolled in a prospective study of posttransfusion hepatitis was studied to determine the possibility of previously unrecognized hepatitis C virus (HCV) transmission. STUDY DESIGN AND METHODS: Before and after transfusion, blood specimens that were negative in first-generation enzyme immunoassay (EIA) were tested by current commercial EIAs, several single-antigen research EIAs, and supplemental tests. RESULTS: Current second- and third-generation EIAs identified five subjects (1.7% of total) who had chronic hepatitis C before transfusion. Twenty additional sera had some reactivity with research EIAs. However, those results were the same before and after transfusion (n = 7), had reverted to partially reactive or nonreactive (n = 8), or could not be confirmed by serologic tests or polymerase chain reaction in follow-up specimens (n = 5). CONCLUSIONS: Transient or restricted reactivity to HCV antigens measured by more sensitive research EIAs does not seem to correspond to recent HCV transmission by transfusion. Whether such reactivity could reflect remote HCV infection, with the potential for chronic or intermittent viremia, remains to be determined.     

Effect of encapsulation on absorption of sumatriptan tablets: data from healthy volunteers and patients during a migraine

BACKGROUND: Some comparative trials of selective serotonin 1B/ID-agonists in migraine have reported -15% lower efficacy for sumatriptan tablets than that reported in placebo-controlled trials. OBJECTIVE: This study was designed to test the hypothesis that the encapsulation methods used to mask active drug may delay absorption of sumatriptan from dosing to 2 hours after dosing (the traditional end point in clinical trials of migraine treatment), an effect that may be enhanced by migraine-associated gastric stasis. METHODS: Two randomized, open-label, 2-way crossover trials were conducted to evaluate the absorption and bioequivalence of conventional 50-mg sumatriptan tablets and encapsulated 50-mg sumatriptan tablets in supine, fasted, healthy volunteers (Glaxo Wellcome protocol SUM40270) and supine patients experiencing a migraine (Glaxo Wellcome protocol SUM40268). Absorption was assessed by calculating the area under the plasma concentration-time curve from dosing to 2 hours after dosing (AUC2) and the times to first measurable plasma concentration, 10 ng/mL, 20 ng/mL, and maximum plasma concentration. Data for the AUC from time zero to infinity and maximum plasma concentration were used to assess standard bioequivalence, which is considered to occur when the 90% CIs for the geometric mean treatment ratios (test/reference) fall between 0.8 and 1.25. RESULTS: Study 1 included 26 healthy subjects (73% men, 27% women; mean age, 39.1 years), and study 2 included 30 patients with migraine (67% women, 33% men; mean age, 42.7 years). Sumatriptan absorption was delayed with the encapsulated tablet compared with the conventional tablet 0 to 2 hours after dosing, particularly during a migraine. AUC2 values with encapsulated sumatriptan compared with the conventional tablet were 21% lower in healthy volunteers (ratio of capsule/tablet, 0.79; 90% CI, 0.588-1.050) and 27% lower in patients experiencing a migraine (ratio of capsule/tablet, 0.73; 90% CI, 0.519-1.023). Standard bioequivalence was demonstrated in both healthy volunteers and patients experiencing a migraine. CONCLUSIONS: Encapsulation delayed absorption of sumatriptan 0 to 2 hours after dosing, particularly during a migraine. This delay in absorption of the encapsulated form may account for the lower efficacy of sumatriptan in some comparative studies.     

Age-dependent production of IgA and IgM autoantibodies against IgG2a in a colony of 129/Sv mice

Although much of the basic immunological work has been done with mice, little is known about anti-IgG autoantibodies in this species. Dresser (1, 2) has reported the occurrence, in CBA mice, of anti-IgG antibody (Ab)(1) detected by a hemolytic-plaque assay after stimulation with endotoxin or immunization against sheep erythrocytes. IgM rheumatoid factor has also been described in various strains of mice with a systemic lupus erythematosus-like disease (3). Recently, we have tried to induce anti-IgG in mice of the 129/Sv strain by inoculating autologous IgG. To our surprise, we found that the sera of all the animals had, before any inoculation, anti-IgG detectable by agglutination of particles coated with autologous IgG. The possibilities to investigate the mechanism of production and the biological role of this kind of Ab prompted us to undertake a study of the nature and specificity of the mouse anti-IgG.     

Radiographic damage in large joints in early rheumatoid arthritis: relationship with radiographic damage in hands and feet, disease activity, and physical disability

An assessment of the onset of radiographic damage in the large joints (hip, knees, shoulders, elbows, ankles and tarsus) in patients with early rheumatoid arthritis, and the relationship of the progression of large joint damage with joint damage in hands and feet, with physical disability, and with cumulative disease activity, was performed in a prospective 6 yr follow-up study. Large joint damage appeared to be an early phenomenon with 20% of the patients having some damage in at least one large joint within 1 yr, and 50% of the patients within 6 yr after disease onset. Radiographic damage in large joints was significantly related to the damage in hands and feet, the physical disability index, and the cumulative disease activity. The initial disease activity at study entry was the only prognostic factor that reached significance.      

Human platelets secrete chemotactic activity for eosinophils

Thrombin-stimulated platelets liberate factors that induce chemotaxis of eosinophils and raise their cytosolic Ca2+ content ([Ca2+]i). The sources of this activity are the dense- and alpha-granules because inhibition of prostaglandin endoperoxide/thromboxane A2 formation and the platelet-activating factor receptor-antagonist WEB 2086 have no effect. Platelets from patients with Storage-Pool Deficiency show about 60% of the normal chemotactic activity with little effect on [Ca2+]i, whereas completely degranulated platelets fail to affect eosinophils. In concentrations secreted by the platelets, adenosine diphosphate (ADP), and platelet factor 4 have no effect, whereas adenosine triphosphate (ATP) induces a strong chemotactic response and increases [Ca2+]i. However, apart from ATP other modulating factors must be involved as platelet releasates induce more chemotaxis than ATP alone. Thus, platelets secrete factors that activate eosinophils and may contribute to inflammatory and allergic processes.