Titanium and bioactive glass-ceramic coated titanium as materials for keratoprosthesis

The current problem with keratoprosthesis is the ingrowth of corneal or conjunctival epithelium into the anterior chamber. This may lead to infections and extrusion of the prosthesis as well as to the development of retroprosthetic membrane and secondary glaucoma. Glass-ceramic coated and uncoated titanium has been tested as material for the keratoprosthesis to prevent epithelial ingrowth. Twenty-two Supra-Descemet's membrane keratoprostheses were inserted in the eyes of 22 rabbits for 1, 2, 4, 8, or 12 months. The prosthesis had an optic part made of polymethylmetacrylate (PMMA). The support for the optic part and the flange of the prosthesis were made of titanium. Eleven of the prostheses were coated with glass-ceramic. The histological sections of the enucleated eyes were prepared through the central part of the cornea and the prosthesis using a cutting-grinding method. The histological analysis was made on both halves of the implants separately giving two analysis areas in each eye. All 11 titanium prostheses were retained for the time period planned. Two glass-ceramic coated prostheses were lost at 2 and 4 weeks, respectively. This was caused by difficulties at surgery due to a thick coating. These eyes were excluded from the histological analysis. No significant ingrowth of epithelium was seen in 15/18 (83%) and in 16/22 (73%) of the analysed areas of the glass-ceramic coated and titanium prostheses, respectively. Titanium appears to be a suitable material for the keratoprosthesis. The ingrowth of the epithelium may be hindered further by coating the titanium with bioactive glass-ceramic.     

Endothelin-1 infusion inhibits plasma insulin responsiveness in normal men

OBJECTIVES: Elevated plasma endothelin (ET)-1 levels have been described in insulin-resistant states such as syndrome X, obesity, non-insulin-dependent diabetes mellitus, and in some studies in essential hypertension. To investigate whether increases in circulating ET-1 to levels observed in insulin-resistant states can modulate insulin levels and/or insulin sensitivity in humans, we assessed these variables during low, non-pressor-dose ET-1 compared with placebo infusion. DESIGN: In a randomized, single blind, crossover design, 10 lean normotensive male subjects received either an intravenous infusion of subpressor doses of ET-1 dissolved in polygeline or a control infusion of polygeline only (placebo). Using dynamic assessment by the minimal model approach with the modified frequent sampling intravenous glucose tolerance test (FSIGT) the following and other parameters were measured: insulin sensitivity; acute insulin response to glucose (AIR(G)) calculated as the average of the three peak values between 2 and 5 min after injection of glucose from which the basal insulin levels were subtracted; the initial area under the curve (AUC(1-19)) from insulin values between time 0 and 19 min and the first-phase insulin secretion (phi1) from insulin kinetics parameters. RESULTS: ET-1 infusion reduced AIR(G) (to 34.85 +/- 4.27 compared with 49.3 +/- 6.9 microU/ml during placebo, P=0.017) and the acute C-peptide response to glucose (to 2.33 +/- 0.41 compared with 3.1 +/- 0.44 ng/ml, P=0.018), decreased plasma insulin levels during the FSIGT compared with placebo (analysis of variance P<0.0001) and decreased the AUC(1-19) (to 2.1 +/- 0.2 compared with 2.9 +/- 0.3 U/l per 20 min, P<0.01) while phi1 tended to be lower. S1 measured during ET-1 infusion was unaltered (11.11 +/- 1.91 x 10(-4) versus 10.88 +/- 2.11 10(-4)/min per mU per l, NS). CONCLUSIONS: These findings demonstrate that an increase in circulating ET-1 to levels observed in insulin-resistant states acutely diminishes the insulin secretory response but does not significantly modify insulin sensitivity.     

Apolipoprotein E allele frequencies in argyrophilic grain disease

Glanzmann's thrombasthenia is a rare inherited hematological disorder defined by deficiency or abnormality of the glycoprotein (GP) IIb-IIIa complex. Presenting symptoms are hemorrhagic events, mainly epistaxis, purpura, or menorrhagia. We describe the clinical course and management of a 14-year-old girl with Glanzmann's thrombasthenia and severe menorrhagia. Following treatment with 20 U of packed red blood cells, 37 U of platelets, 7 U of fresh frozen plasma, cryoprecipitate, intravenous estrogens, and methylergotrine maleate with no improvement, the uterine cavity was packed for 48 hr. This unusual procedure halted the bleeding and avoided the necessity for a hysterectomy. When treating acute menorrhagia in patients with Glanzmann's thrombasthenia, the physician should be familiar with the characteristics and all treatment modalities for this disorder.     

Inflammatory breast carcinoma incidence and survival: the surveillance, epidemiology, and end results program of the National Cancer Institute, 1975-1992

BACKGROUND: Little is known about the cause of inflammatory breast carcinoma (IBC), the most aggressive form of breast cancer. To the authors' knowledge, no studies have investigated whether IBC risk factors are different from those for breast carcinoma overall, and there has been only one report of IBC incidence and survival patterns. METHODS: The authors used data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute for the period 1975-1992 to calculate age-adjusted incidence and survival rates for 913 white and 121 African American women with IBC involving dermal invasion of lymphatic ducts and 166,375 white and 13,674 African American women with other types of breast carcinoma (non-IBC). RESULTS: Between 1975-1977 and 1990-1992, IBC incidence doubled, increasing among whites from 0.3 to 0.7 cases per 100,000 person-years and among African Americans from 0.6 to 1.1 cases. However, rates for African Americans varied due to the small numbers of IBC cases. The twofold increase in IBC incidence was higher than that observed for non-IBC during the same period (27% for African Americans and 25% for whites). IBC patients were significantly younger at diagnosis than non-IBC patients; and among both IBC and non-IBC patients, African Americans were younger than whites. Overall survival was significantly worse for IBC patients than for non-IBC patients and for African Americans than for whites. Among whites, 3-year survival improved more for IBC patients than for non-IBC patients between 1975-1979 and 1988-1992, increasing from 32% to 42% for IBC patients (P=0.0001) and from 80% to 85% for non-IBC patients (P=0.0001). CONCLUSIONS: The disparities observed in incidence trends and age at diagnosis, particularly according to race, highlight the need for further investigation of the differences between IBC and non-IBC incidence.     

Renal amyloidosis in a drug abuser

Drug abusers, particularly those who inject drugs s.c. ("skin popping"), may develop amyloidosis. Chronic infections are thought to play a pathogenetic role in this setting. A patient is presented who had a history of "skin popping" cocaine and heroin and developed nephrotic syndrome, with an elevated serum creatinine and a creatinine clearance of 61 mL/min. Renal biopsy demonstrated amyloidosis. Treatment with colchicine was initiated, and proteinuria decreased to near normal levels after 12 months. Concomitant with the decrease in proteinuria, creatinine clearance improved, although a repeat renal biopsy failed to show any significant improvement in amyloid burden. These observations suggest that colchicine may be a useful treatment in reversing the proteinuria of renal amyloidosis associated with drug abuse. Furthermore, clinical improvement may occur before any demonstrable regression in the amyloidosis.     

高强混凝土新型梁柱节点构造的抗震性能试验研究

针对低-中震害区构件有限延性的要求,提出了2种新型钢筋混凝土梁柱节点的构造形式:在节点区加配斜钢筋,或梁主钢筋在节点区弯起.它们既可满足有限延性的要求,又可避免节点区钢筋密集.通过对4个高强混凝土梁柱节点在低周反复荷载作用的试验表明:2种新型节点均可提高节点延性,将节点的位移延性系数分别从3提高到3.5和4.4;在节点区加配斜钢筋的试件可提高强度15%.因此,对于有限延性要求的节点,是最佳的节点构造形式.     

Cross-reactive cellular immune response to circumsporozoite proteins of Plasmodium vivax and P. falciparum in malaria-exposed individuals

The present review offers a new look at capillary isoelectric focusing (cIEF) by centering on the most troublesome aspects of the technique, namely: 1) how to modulate the slope of the pH gradient, for increasing resolution (equivalent to pH gradient engineering, as easily available in immobilized pH gradients); and 2) how to keep proteins in solution at (and in the proximity of) the pl value. A simple solution is offered in the first case: addition, to the standard 2-pH-units interval, of separators or spacers, i.e., of amphoteric molecules (either single or in combination) able to locally flatten the pH and increment resolution. Examples of the separation of fetal and glycated hemoglobins are provided. In the second case, a unique solubilization power (while maintaining full protein integrity and enzyme activity) is obtained if class I solubilizers are used. They consist of mixtures of sugars (e.g., sucrose and sorbitol) at ca. 1 M concentration, with zwitterions (up to 1 M) such as the class of nondetergent sulfobetaines, but also taurine and some of the Good's buffers (e.g., CAPS). In these solvents, the protein exists in a state of superhydration and its solubility is greatly augmented. The review ends with an excursus on the use of isoelectric buffers in zone electrophoretic separations. Such isoelectric buffers offer unique advantages: They permit very-high-voltage gradients (up to 1000 V/cm) and thus minimize analysis times (down to a few min in 30-35 cm long capillaries). This results in a marked increase in resolution, due to minimal diffusion-driven peak spreading. Such buffers are finding unique applications for generating peptide maps of tryptic digests of proteins and also in the analysis of oligonucleotides.     

Anti-plasmodial and anti-trypanosomal activity of synthetic naphtho[2,3-b]thiopen-4,9-quinones

Naphtho[2,3-b]thiophen-4,9-quinone and five derivatives were prepared using the Friedel-Crafts reaction and tandem-lithiation of aromatic diethylamides. These quinones were evaluated for their trypanocidal and anti-plasmodial activities by their effects on: (1) growth of epimastigote forms of Trypanosoma cruzi in vitro, (2) lysis of trypomastigote forms of T. cruzi in murine blood, (3) growth of Plasmodium falciparum in vitro, and (4) inhibition of the recombinant enzyme trypanothione reducatase. The parent compound, naphtho[2,3-b]thiophen-4,9-quinone (3a), was among the most active quinone tested in vitro against P. falciparum at 0.2 microM. However, it was inactive against P. berghei-infected mice treated with 2.3 mmol/kg daily for 5 days. Most of the quinones prepared were active against T. cruzi epimastigotes in culture but exhibited weak activity at 4 degrees C against trypomastigotes in murine blood as well against the enzyme trypanothione reducatase. Further structural modifications will be necessary to improve the in vivo activity of the naphthothiophenquinones.     

基于静力触探的土层自动划分方法与不确定性表征

提出了一种基于I_c数据自动划分土层的贝叶斯方法,所提方法不仅能够在考虑I_c的空间变异性的条件下自动划分土层,识别最可能的土层界面,而且能够定量地表征土层界面的不确定性,为制定下一步勘探方案和岩土工程设计提供参考依据。本文采用基于子集模拟的贝叶斯更新方法(CBUS)求解贝叶斯方程,产生土层厚度的后验分布样本,并计算每个可能的土层数目对应的模型证据,确定最可能土层数和最可能的土层界面深度,计算界面深度的标准差作为土层界面不确定性的量化指标。最后,通过上海市轨道交通10号线伊犁站基坑开挖现场的I_c数据和模拟I_c数据说明了所提方法的有效性和正确性。结果表明:所提方法划分的土层合理地反映了不同土层I_c的统计特性。相邻土层I_c的统计特性差异越大,界面深度的标准差越小,识别出的土层界面越可靠,反之亦然。