Severe central nervous system thrombotic events in hemoglobin Sabine patient

Hemoglobin (Hb) Sabine is a rare, unstable Hb variant resulting from the point mutation in codon 91 (CTG --> CCG) of beta-globin gene. We report a case of Hb Sabine patient with mild hemolytic anemia, unusually high Hb F level and severe central nervous system thrombotic disturbances. We have tried to elucidate possible genetic background of this unusual Hb Sabine phenotype. Extremely high level of Hb F and rather mild anemia in our patient could be partially explained by the presence of G gamma Xmn I polymorphism. This case of Hb Sabine, unlike all other reported to date, shows extremely severe thromboembolic complications. It is our opinion that the hypercoagulable state described in thalassemia is not the only factor responsible for this specific clinical state. The presence of MTHFR C677T mutation in heterozygous state found in our patient and unstable Hb Sabine molecules could contribute to development of thromboembolic phenomena. However, it remains unclear whether other factors participate in pathogenesis of the disease. In this paper we emphasize different genetic background of father and son both affected with Hb Sabine, but with markedly different severity of the disease.     

GFAP promoter drives Müller cell-specific expression in transgenic mice

PURPOSE: In an attempt to identify Müller cell-specific promoters and to better understand the gene regulatory mechanisms in retinal glial cells, the expression of the glial fibrillary acidic protein (GFAP) gene was studied in Müller cell cultures and in GFAP-enhanced green fluorescent protein (EGFP) transgenic mice. METHODS: A transfection assay of GFAP-luciferase constructs carrying a series of nested deletions was performed in an established Müller cell line. For in vivo analysis, transgenic mice were generated by injecting a construct carrying a 2.5-kb, 5' fragment of the mouse GFAP gene linked to the EGFP gene. Isolated retinas from transgenic mice were screened for GFP expression. Subsequently, the identity of the GFP-expressing cells was established by immunostaining cryostat sections of the retina with antibodies against Müller cell antigenic markers. Induction of the transgene and the endogenous GFAP gene was examined by injecting ciliary neurotrophic factor (CNTF) into the eye. RESULTS: The DNA transfection data suggested that proximal 5' sequences of the GFAP gene are sufficient to direct high-level reporter expression in Müller cell cultures. In transgenic mice, GFP fluorescence appeared in radially oriented processes that spanned almost the entire thickness of the retina. Immunostaining with antibodies to cellular retinaldehyde-binding protein (CRALBP) and glutamine synthetase showed that the GFP-expressing cells were Müller cells. GFP-expressing Müller cells were observed in the retinas of both albino and pigmented transgenic mice. In eyes injected with CNTF, both GFP and GFAP levels were highly elevated. These observations suggest that the 2.5-kb, 5' GFAP sequence can direct inducible reporter gene expression in Müller cells. In addition to Müller cells, a few GFP-labeled astrocytes were present in the adult retina. In the developing retina, GFP-expressing astrocytes were first present at the optic nerve head, and as development progressed, the cells gradually moved toward the periphery of the retina and acquired their adult, stellate morphology. CONCLUSIONS: The present study shows that the 2.5-kb, 5' flanking region of the mouse GFAP gene can be used to express GFP, and possibly other genes, specifically in Müller cells in the mouse retina. Furthermore, expression of the transgene can be upregulated by intravitreal injection of CNTF.     

Identification of platelet proteins that bind alloantibodies and autoantibodies

We have used the techniques of radioimmunoprecipitation (RIP) and Western blot to identify the membrane proteins that bind certain alloantibodies. Anti-PlA1 sera precipitated two bands, corresponding to platelet glycoproteins IIb and III, whether or not calcium was present during the procedure. By Western blot, this antibody bound only glycoprotein III. Anti-PlA1 serum does not precipitate proteins from the platelets of a patient with Glanzmann's thrombasthenia. Two monoclonal antibodies reacting with lymphocyte HLA antigens, as well as sera from highly allosensitized patients, precipitated bands of 38,500 and 13,500 daltons. These bands correspond to the molecular weights of the two subunits of the HLA antigen, as it has been described for other cell types. The patients' sera also precipitated a protein of 72,000 daltons from some platelets. The sera of two patients with quinidine- induced thrombocytopenia precipitated a 138,000-dalton band (glycoprotein Ib-alpha) in the presence of quinidine. The purified IgG antibody from one patient did not require other plasma factors to bind to platelets in the presence of quinidine, while purified antibody from a second patient required plasma factors other than, or in addition to von Willebrand factor. Although several sera from patients with idiopathic thrombocytopenic purpura (ITP) were tested, only one precipitated membrane proteins by the RIP method; this serum identified binding proteins corresponding to glycoproteins IIb and III.     

An evaluation of polymer rotary instruments' ability to remove healthy, non-carious dentine

The aim of this study was to confirm that Smartprep burs do not cut non-carious, healthy dentine. Twenty non-carious extracted molars were trimmed with a diamond bur to remove enamel and to create a flat dentine surface. A new Smartprep bur (RA # 4) was applied to each tooth for 30 seconds. As a control, a new number three round stainless steel bur was applied to each tooth. The mean dentine loss was 4.25 mg (range 1.4 - 9 mg) for Smartprep burs and 12.21 mg (range 7.6 - 16.5 mg) for stainless steel burs. The Smartprep burs remove significantly less dentine than stainless steel burs.     

鼻咽癌切除术后患者血浆DNA的快速变化

摘要：目的监测鼻咽癌病人于肿瘤切除手术期间和术后,其血浆DNA浓度的变化,以了解血浆DNA在体内的动态变化情况。方法静脉抗凝血分离血浆,从血浆中提取DNA,用实时定量PCR方法分别测定手术前、后鼻咽癌病人血浆DNA的浓度。结果肿瘤手术初期,病人血浆DNA的浓度会快速升高,随后其水平会迅速下降,DNA在血浆中的半衰期为126min;当血浆DNA水平降到最低时,其水平又会再次升高,至2385：min后出现第二个峰值。结论癌症病人游离DNA可以极其迅速地从血循环中被清除,第二个峰值的水平可能对评估组织损伤严重程度具有一定的临床意义,此研究为进一步研究血浆肿瘤DNA在其他肿瘤中的变化奠定了基础。     

Visual outcome and progression of retinopathy after cataract surgery in diabetic patients

Purpose: Diabetes mellitus is a major cause of visual impairment in developed countries through retinopathy and is frequently complicated by cataract formation. The present study examines the visual outcome of cataract surgery in diabetic patients.
Methods: A retrospective study was performed over a 26 month period in a general hospital eye clinic. Eighty-five consecutive diabetic patients who underwent cataract surgery were categorized according to their type of diabetes, duration and treatment, operative technique, pre-operative visual acuity (VA) and degree of retinopathy. Visual acuity and retinopathy status were recorded at a minimum of 4 months postoperatively. Factors affecting visual outcome and progression of retinopathy were then examined.
Results: Of the 107 eyes of the 85 consecutive cases, 55 were without retinopathy (NR), 21 had background retinopathy (BDR), six had background retinopathy with macular oedema (BDR/MO), four had proliferative retinopathy and 12 cases had inadequate fundal view. In the NR and BDR groups, 90 and 81% of patients, respectively, had improved VA compared with 33% of patients with BDR/MO. Retinopathy progressed in 50% of BDR/MO patients compared with progression in 9 and 19% of NR and BDR patients, respectively.
Conclusion: The present study illustrates the poor visual outcome in patients with severe, untreated retinopathy, particularly maculopathy, following cataract surgery. Larger prospective studies are needed to better define risk groups and pre-operative treatment strategies.