Chronic mercury exposure impairs the sympathovagal control of the rat heart

Mercury is known to cause harmful neural effects affecting the cardiovascular system. Here, we evaluated the chronic effects of low‐dose mercury exposure on the autonomic control of the cardiovascular system. Wistar rats were treated for 30 days with HgCl₂ (1st dose 4.6 μg/kg followed by 0.07 μg/kg per day, intramuscular) or saline. The femoral artery and vein were then cannulated for evaluation of autonomic control of the hemodynamic function, which was evaluated in awake rats. The following tests were performed: baroreflex sensitivity, Von Bezold‐Jarisch reflex, heart rate variability (HRV) and pharmacological blockade with methylatropine and atenolol to test the autonomic tone of the heart. Exposure to HgCl₂ for 30 days slightly increased the mean arterial pressure and heart rate (HR). There was a significant reduction in the baroreflex gain of animals exposed to HgCl₂. Moreover, haemodynamic responses to the activation of the Von Bezold‐Jarisch reflex were also reduced. The changes in the spectral analysis of HRV suggested a shift in the sympathovagal balance toward a sympathetic predominance after mercury exposure, which was confirmed by autonomic pharmacological blockade in the HgCl₂ group. This group also exhibited reduced intrinsic HR after the double block suggesting that the pacemaker activity of the sinus node was also affected. These findings suggested that the autonomic modulation of the heart was significantly altered by chronic mercury exposure, thus reinforcing that even at low concentrations such exposure might be associated with increased cardiovascular risk.     

椎体复位器治疗胸腰椎骨折过程中的生物力学参数变化

目的:对胸腰椎压缩性骨折的复位目前主要是通过Harrington棒的撑开或Dick等器械压缩,间接地使压缩的椎体得到复位.但复位的力量不易掌握,效果往往也不够理想.因此,需要了解和掌握复位器未发生变形时所能承受的最大应力及椎体复位器在椎体内撑开复位的应力与位移的关系.方法:实验于1998-10/2003-04在上海市材料力学研究所、上海市第九人民医院生物力学研究室及上海第二医科大学解剖教研室市生物力学研究室完成.自行设计的椎体复位器为圆柱形,顶端的上下开启由尾端的圆形手柄控制.实验方法:①椎体复位器的抗压力实验:将椎体复位器撑开到最大后进行轴向压缩实验,当复位器刚好发生形变时的轴向压应力,即是复位器进行轴向撑开时所能承受最大应力.②新鲜小牛骨椎体抗轴向压力实验:在36个新鲜小牛骨椎体上制作压缩性骨折模型时,了解椎体形变时的应力形变的关系.实验前测出每个椎体的高度值,发生压缩形变后,再测量每个椎体的高度值,并在机器上测出相应的压应力值.③椎体复位器复位压缩性小牛骨椎体的生物力学实验:将20个新鲜小牛骨胸腰椎椎体分成2组,每组10个椎体.在轴向载荷下压缩椎体,制作压缩性骨折的模型,1/2椎体高度压缩组其压缩后高度接近原有椎体高度的1/2,2/3椎体高度压缩组其压缩后高度接近原有椎体高度的2/3.从椎体椎弓根两侧放入复位器,将压缩的椎体予以复位.了解复位器在椎体内的撑开应力与复位时位移关系.结果:①复位器未发生变形时所能承受的最大力为281 N.②36个新鲜小牛骨椎体在承受轴向载荷发生变形时屈服点的平均应力为74.96 kPa,各数据符合正态分布(t=16.044,P＜0.01).③1/2椎体高度压缩组和2/3椎体高度压缩组复位器在椎体内撑开后应力值差异无显著性意义(t=0.835,P＞0.05).结论:椎体压缩程度与椎体内撑开复位的力量没有直接关系,自行设计的椎体复位器在椎体内撑开复位的力量远小于复位器的屈服点应力.     

Low retention of white cell fragments by polyester fiber white cell- reduction platelet filters

BACKGROUND: There is intense interest in the potential of current white cell (WBC)-reduction filters to prevent the alloimmunization of patients by the residual donor WBCs in filtered blood components transfused to them. Little attention has been paid to the capacity of current synthetic fiber filters to remove WBC membrane fragments bearing detectable leukocyte antigens. STUDY DESIGN AND METHODS: Fluorescein isothiocyanate-conjugated monoclonal antibody to a universal WBC membrane antigen (CD45) and high-speed centrifugation coupled with ficoll-hypaque differential sedimentation were used to quantitate low-density WBC fragments in single-donor platelet components before and after filtration to determine if a polyester fiber filter retained WBC fragments. RESULTS: Prefiltration measurements in 25 single-donor platelet components indicated that WBC fragments increased with length of storage up to 5 days at room temperature (p < 0.0001). When fragments in eight components were measured before and after filtration, absolute values for differences were insignificant (p = 0.15). CONCLUSION: WBC fragments were poorly retained by these polyester fiber WBC-reduction filters. The antigenicity of WBC fragments could contribute to the WBC alloimmunization of some recipients of WBC-reduced blood components.     

CD7+, CD4-, CD8- acute leukemia: a syndrome of malignant pluripotent lymphohematopoietic cells

Following our initial observation of in vivo conversion of CD7+, CD4-, CD8- acute lymphoblastic leukemia (ALL) cells from lymphoid to myeloid lineages (Proc Natl Acad Sci (USA) 81:253, 1984) we have studied eight additional cases of ALL with this leukemic cell phenotype. The CD7+, CD4-, CD8- phenotype was associated with a distinct clinical entity with those affected predominantly male (either less than 35 years or greater than 65 years of age), with frequent mediastinal and/or thymic masses, skin and CNS disease, high peripheral WBC counts, and bone marrow blasts that were morphologically L1 or not ascribable to a specific lineage. These patients did not respond to conventional chemotherapeutic regimens for either acute lymphoid or myeloid leukemias. No common karyotype or T-cell gene rearrangement pattern could be defined. Importantly, seven of eight patient's leukemic cells studied were capable of multilineage (myeloid, erythroid, monocytoid, megakaryocytoid, and lymphoid) differentiation in vitro. Data is presented suggesting that CD7+, CD4-, CD8- leukemias, in many instances, are leukemias of immature hematopoietic cells. The development of novel therapeutic approaches to this form of leukemia will be necessary to alter its poor prognosis.     

Phenotypic characterization of human bone marrow granulocyte-macrophage forming progenitor cells

Cell surface antigens of the human bone marrow CFU-C have been studied. Human marrow cells were incubated with a variety of monoclonal antisera and complement prior to culture in semisolid media. By using indirect immunofluorescent studies, the percentage of bone marrow cells binding the antibodies was determined. The CFU-C phenotype is HLA+, la+, 4F2+, 3A1-, and DUALL-1-. This study provides information that is useful in the study of myeloid cell ontogeny and necessary for the use of some of these reagents in the treatment of bone marrow cells prior to human bone marrow transplantation in various clinical settings.     

Nonionic versus ionic contrast media in intravenous urography: clinical trial in 1,000 consecutive patients

A double-blind clinical trial was performed in 1,000 consecutive patients to compare the safety and efficacy of intravenously administered nonionic (iohexol) and ionic (metrizoate) urographic contrast media. The patients ranged in age from 10 to 80 years. The incidence of mild to moderate adverse effects was 7.7% with iohexol and 31.2% with metrizoate. No serious reactions were recorded with either of the contrast media. Urography with iohexol was found to give better parenchymal opacification, pelvocalyceal opacification, and overall quality. The sum of examinations with good and excellent overall quality was 97.8% with iohexol and 91.1% with metrizoate. The frequency of poor overall quality urograms was 1.6% with iohexol and 7.5% with metrizoate. The data suggest that iohexol is safer and more frequently produces urograms of better quality.     

Steroid receptor status difference in recurrent intracranial meningioma and breast cancer in the same patient

The authors report a case of multiple recurrent intracranial meningioma associated with breast cancer in a menopausal woman. High affinity estrogen (ER) and progestin receptors (PR) were assayed independently in the meningioma and the tumor. ER were found to be very low in the meningioma and high in the breast tumor. On the contrary PR were found to be high in the meningioma and could be not detected in the breast tumor. This unique case suggests that meningioma and breast cancer are not under the same type of hormonal influence.     

Measuring health and well-being effects in family caregivers of children with craniofacial malformations

Purpose  

This research explores the sensitivity of three generic instruments for preference-weighting health states of family caregivers of children with craniofacial malformations (CFM). We also examine the construct validity of the new CarerQol instrument measuring caregiver burden and general quality of life.     

Gestational diabetes mellitus: is a diagnosis associated with an increase in maternal anxiety and stress in the short and intermediate term?

OBJECTIVE: To examine anxiety levels of women diagnosed with gestational diabetes mellitus (GDM) and to compare these with glucose-tolerant (GT) women at similar stages of pregnancy. RESEARCH DESIGN AND METHODS: Prospective longitudinal study conducted on 50 women with GDM and 50 GT women. All women completed the Mental Health Inventory (MHI-5) forms and the Speilberger State-Trait Anxiety Inventory (STAI) at the beginning of the third trimester, antepartum, and 6 weeks postpartum. Specific questions were also assessed using a Likert scale. RESULTS: Women with GDM, compared with GT women, had a higher level of anxiety (state rather than trait) at the time of the first assessment. However, before delivery and in the postpartum period, there were no significant differences in anxiety scores between the two groups. Women in both groups were positive about being tested for GDM and wished to be tested during future pregnancies. CONCLUSIONS: There were no sustained increased levels of anxiety for women diagnosed with GDM. Concerns expressed about causing sustained maternal anxiety by testing for GDM could not be substantiated.