Cardiomyocytes in vitro adhesion is actively influenced by biomimetic synthetic peptides for cardiac tissue engineering

Scaffolds for tissue engineering must be designed to direct desired events such as cell attachment, growth, and differentiation. The incorporation of extracellular matrix-derived peptides into biomaterials has been proposed to mimic biochemical signals. In this study, three synthetic fragments of fibronectin, vitronectin, and stromal-derived factor-1 were investigated for the first time as potential adhesive sequences for cardiomyocytes (CMs) compared to smooth muscle cells. CMs are responsive to all peptides to differing degrees, demonstrating the existence of diverse adhesion mechanisms. The pretreatment of nontissue culture well surfaces with the (Arginine-Glycine-Aspartic Acid) RGD sequence anticipated the appearance of CMs' contractility compared to the control (fibronectin-coated well) and doubled the length of cell viability. Future prospects are the inclusion of these sequences into biomaterial formulation with the improvement in cell adhesion that could play an important role in cell retention during dynamic cell seeding.     

小B细胞恶性淋巴瘤病理鉴别诊断

小Ｂ细胞恶性淋巴瘤主要包括 :( 1)Ｂ细胞慢性淋巴细胞性白血病 /小淋巴细胞性淋巴瘤 (Ｂ ＣＬＬ/ＳＬＬ) ;( 2 )淋巴浆细胞性淋巴瘤 (ＬＰＬ) ;( 3 )套细胞淋巴瘤 (ＭＣＬ) ;( 4 )滤泡性淋巴瘤 (ＦＬ) ;( 5 )边缘区Ｂ细胞淋巴瘤 (ＭＺＬ)。其中ＭＺＬ包括三种类型 :粘膜相关淋巴组织型 (ＭＡＬＴ) ;淋巴结边缘区Ｂ细胞淋巴瘤 ;脾边缘区Ｂ细胞淋巴瘤 (ＳＭＺＬ)。ＷＨＯ恶性淋巴瘤新分类将这几种淋巴瘤都归于各自具有临床表现、形态学、免疫表型、遗传学特点的独立疾病[1] 。各种不同类型小Ｂ细胞恶性淋巴瘤的病理诊断和鉴别诊断常会遇到困…     

Measuring the elastic modulus of ex vivo small tissue samples

Over the past decade, several methods have been proposed to image tissue elasticity based on imaging methods collectively called elastography. While progress in developing these systems has been rapid, the basic understanding of tissue properties to interpret elastography images is generally lacking. To address this limitation, we developed a system to measure the Young's modulus of small soft tissue specimens. This system was designed to accommodate biological soft tissue constraints such as sample size, geometry imperfection and heterogeneity. The measurement technique consists of indenting an unconfined small block of tissue while measuring the resulting force. We show that the measured force-displacement slope of such a geometry can be transformed to the tissue Young's modulus via a conversion factor related to the sample's geometry and boundary conditions using finite element analysis. We also demonstrate another measurement technique for tissue elasticity based on quasi-static magnetic resonance elastography in which a tissue specimen encased in a gelatine-agarose block undergoes cyclical compression with resulting displacements measured using a phase contrast MRI technique. The tissue Young's modulus is then reconstructed from the measured displacements using an inversion technique. Finally, preliminary elasticity measurement results of various breast tissues are presented and discussed.     

The estimation of magnesium in small biological samples by flame spectrophotometry

Studies of human magnesium metabolism in this laboratory called for a simple and reliable method of estimating the magnesium content of large numbers of small biological specimens (Montgomery, 1960). It has been found that a technique involving the Unicam S.P. 900 flame spectrophotometer fulfils this need.     

Determination of the activity of diamine oxidase in extremely small tissue samples

Inflammation Research -     

Stage is a better prognostic indicator than morphologic subtype in primary noncutaneous T-cell lymphoma

The authors reviewed 28 primary noncutaneous T-cell lymphomas, referred to the Comprehensive Cancer Center Amsterdam, using the updated Kiel classification. Clinical course was related with stage of disease, morphologic subtype, and immunophenotype of the tumor cells. The incidence of primary noncutaneous T-cell lymphomas was 4.1 cases per 1,000,000 people per year. Morphologic classification was difficult and arbitrary. Immunohistochemistry contributed considerably in diagnosis of this group of tumors. All primary noncutaneous T-cell lymphomas had a poor prognosis, with no significant difference between predominantly small cell (low-grade) and large cell (high-grade) tumors. The only parameter significantly correlating with survival was the stage of the disease at presentation. The results suggest that all types of primary noncutaneous T-cell lymphoma are to be considered high grade and that primary localization (cutaneous vs. noncutaneous) and stage of disease at presentation appear to be more important as predictors of clinical outcome than morphologic or immunophenotypic subtype.     

Break in the BCL1 locus is closely associated with intermediate lymphocytic lymphoma subtype

The t(11;14)(q13;q32) is a recurring translocation associated with some chronic B-cell lymphocytic malignancies; the putative protooncogene BCL1, located at the chromosome band 11q13, can be involved during the translocation process. In order to determine if BCL1 rearrangement is associated with a particular subtype of lymphoma, we analysed 131 B-cell non-Hodgkin's lymphoma samples by Southern blot analysis, using a BCL1 probe. The BCL1 locus was rearranged in 9 out of 25 (36%) cases of intermediate lymphocytic cell lymphomas (ILL), in 1 out of 8 cases of diffuse small cleaved cell lymphoma, in 1 out of 12 cases of diffuse mixed cell lymphoma, and in 1 out of 21 cases of diffuse large cell lymphoma. In contrast, BCL1 was never found rearranged in any of the 46 follicular lymphomas analysed. The BCL2 gene was in germ-line configuration in all ILL. Sequential hybridization of Southern blots with JH, C mu, and BCLI probes identified comigrating fragments in only one case of ILL, which suggests that, in all the other cases, either the rearrangement of BCL1 did not result from a t(11;14) translocation or the break on chromosome 14 occurred outside the JH or C mu regions. These results indicate that rearrangement of the BCL1 locus may be closely associated with ILL and could be considered as a genotypic marker of this lymphoma subtype.     

Coxiella burnetii in non-Hodgkin lymphoma tissue samples: Innocent until proven otherwise?

Purpose

Coxiella burnetii has been suggested as a potential cause of B-cell non-Hodgkin lymphoma (B-NHL), as C. burnetii was detected in B-NHL tissues. To further investigate this potential relationship, we hypothesized that among subjects previously exposed to C. burnetii, the bacterium is more frequently detectable in tissues of patients with B-NHL (cases) compared to patients without B-NHL (controls).

Bone marrow involvement by nasal NK cell lymphoma at diagnosis is uncommon

To look for subtle evidence of marrow involvement in nasal NK cell lymphoma at diagnosis, we retrospectively studied trephine biopsy specimens from 25 consecutive patients by 2 sensitive techniques: CD56 immunohistochemistry and Epstein-Barr virus-encoded RNA in situ hybridization (EBER ISH). Only 2 patients had marrow involvement by NK cell lymphoma at diagnosis. In 3 additional patients, marrow involvement developed during or after systemic recurrence. All 5 positive cases were revealed by EBER ISH, but only 3 cases showed CD56 immunoreactivity. Among the 5 cases, only 2 were recognized by morphologic assessment. All 5 patients died, often within a short period, compared with a mortality of 50% for patients without demonstrable marrow involvement. Marrow involvement is distinctly uncommon in nasal NK cell lymphoma at diagnosis, and EBER ISH is the most sensitive technique for the demonstration of occult NK cell lymphoma. Despite the low frequency of marrow involvement in nasal NK cell lymphoma, EBER ISH is worthwhile to identify the minor subgroup of patients with a high likelihood of early death due to disease and when autologous bone marrow or peripheral blood stem cell transplantation is contemplated.     

Extracellular matrix composition of full-thickness defect repair tissue is little influenced by exercise in rat articular cartilage.

Full-thickness articular cartilage defects in the femoral condyles of adult rats were examined four and eight weeks after injury. Quantitative polarized light microscopic analysis showed that birefringence of the tissue in the central repair area increased more in rats exercised on a treadmill. Glycosaminoglycan content in the repair tissue was also higher than in the intermittent active motion group at four weeks after injury, but by eight weeks the levels were similar in both groups. No normal-looking articular cartilage was formed in the lesions, and only in one animal type II collagen was observed in the superficial zone of repair tissue. No 3B3(-) antigenicity of the proteoglycans was seen during repair. In conclusion, exercise minimally modified the repair of full-thickness articular cartilage defects in adult rats. The repair in the exercised group may occur slightly faster in the early stages but no difference was seen at the eight week time interval between the exercised and the intermittently active group.     

The survival of neural precursor cell grafts is influenced by in vitro expansion

Embryonic neural precursor cells (ENPs) provide a potential alternative for transplantation in neurodegenerative diseases, as they can be expanded in culture, avoiding many of the practical obstacles that limit the application of transplanting primary neurones. However, grafts of ENPs into animal models show variable survival and limited differentiation into neurones. The effect of expansion time on their ability to survive and differentiate may be an important factor in this and has not been examined directly. In these experiments, murine and human ENPs were expanded for short (4 weeks) and long (20 weeks) periods before transplantation into the adult rat striatum. Whereas grafts of both short- and long-term expanded human ENPs survived for 4 weeks following transplantation, by 20 weeks all long-term expanded grafts had disappeared. Murine ENPs behaved similarly: only grafts of short-term expanded ENPs survived at 12 weeks following transplantation. RT-PCR analysis of ENP cultures after 4 and 20 weeks of expansion demonstrated changes in expression of a number of different groups of genes. We conclude that long-term expansion of ENPs profoundly impairs their ability to survive long-term after transplantation into the adult brain. This has implications for the potential use of these cells for neural transplantation strategies.     

Determination of the structure of tissue samples using X-ray small angle scattering

X-ray small angle scattering has been used in material science for about 50 years. In diagnostic medicine, it has been applied for some years. The theoretical background is the diffraction of monochromatic X-rays by the electrons of small particles. The widening of the primary beam by those samples allows a conclusion regarding particle size, size distribution, and the form of the particles. The camera requires a well-defined and small X-ray beam which has to be entrapped exactly behind the sample. To date, the medical application has been carried out mainly by the comparison of the measured curve with that of standard samples. It can be suggested that in the near future its application in medicine will increase particularly with regard to in vivo measurements. For this purpose, new cameras will have to be developed. An exact evaluation of the result requires a thorough knowledge of the theoretical basis.     

Sleep structure in blindness is influenced by circadian desynchrony

We examined the structure, duration and quality of sleep, including non‐rapid eye movement sleep and rapid eye movement sleep, in 11 blind individuals without conscious light perception and 11 age‐ and sex‐matched sighted controls. Because blindness is associated with a greater incidence of free‐running circadian rhythms, we controlled for circadian phase by a measure of melatonin onset timing. When circadian rhythm was entrained and melatonin onset occurred at normal times, sleep structure did not differ between blind and sighted individuals. On the other hand, an abnormal timing of the circadian phase, including delayed, shifted and unclassifiable melatonin onsets, led to larger rapid eye movement sleep latencies and increased wake times. No differences were observed for stages of non‐rapid eye movement sleep, either between congenital and late blind and sighted individuals, or across the different circadian phases. Moreover, abnormal circadian phases were more common in the blind (n = 5) than the sighted (n = 2) sample. Our findings suggest that the sleep structure of blind individuals depends on entrainment of circadian phase, rather than on the absence of vision.     

The dynamic sensitivity of pyramidal tract neurones is influenced by previous activity

Summary The dynamic sensitivity of Pyramidal Tract (PT) neurones has been examined in silent cells and after pre-activation with an action potential evoked at different intervals before the discharge onset. In the resting conditions the dynamic sensitivity increases after the first interspike interval of the repetitive discharge. When a conditioning spike precedes the discharge onset by 50 ms (i.e. of a time sufficient for its afterhyperpolarization, AHP, to fade out) the dynamic sensitivity becomes uniform throughout the ramp. This linearizing effect progressively declines when the conditioning interval is increased to 100 and 150 ms and is attributed to the depression induced by the conditioning spike on the AHP of the first spike of the ramp discharge. In natural conditions, the effect would be entirely developed when the neurones fire at their minimal discharge rate (1/AHP duration).     

The perceived duration of emotional face is influenced by the gaze direction

The present research investigates the effects of gaze direction on the perceived duration of the presentation of angry and happy expressions. When the facial expression was angry, a straight gaze elongated the perceived duration of the expression compared with an averted gaze. However, there was no effect of gaze direction when the facial expression was happy. These findings indicate that the subjective estimation of time is elongated when the observer encounters a socially important survival signal, considering that an angry face with a straight gaze may be perceived as a threat requiring a fight-or-flight response.