CD4-independent protective cytotoxic T cells induced in early life by a non-replicative delivery system based on virus-like particles

The relative immaturity of the neonatal immune system limits CD4(+) Th1 and cytotoxic T lymphocyte (CTL) responses, and represents a significant challenge for the development of vaccines against intracellular pathogens. In this report, we demonstrate the ability of a non-replicative delivery system based on parvovirus-like particles (VLP) to induce CTL responses in the neonatal period. A single immunization of 1-week-old BALB/c mice with recombinant VLP carrying a CD8(+) T cell determinant from lymphocytic choriomeningitis virus (VLP-LCMV) induced antigen-specific CD8(+) cytotoxic T cells that were similar to those elicited by adult immunization, as assessed by cytotoxic activity, interferon (IFN)-gamma secretion, cytotoxic precursor cell frequencies, in vitro avidity for antigen and protective activity against viral challenge. These CTL responses are elicited within 2 weeks of a single immunization, in the absence of adjuvant and independently of the presence and help of CD4(+) T cells, highlighting the potential of VLP as candidate vaccine vectors in early life.     

Retrograde migration of glove powder in the human female genital tract

BACKGROUND: This study in humans was undertaken to evaluate earlier results from animal research showing a retrograde migration of glove powder from the vagina into the intra-abdominal cavity. METHODS: One study group was gynaecologically examined with powdered gloves the day before an abdominal hysterectomy and another group 4 days pre-operatively. There were two control groups similarly examined with powder-free gloves. Cell smears were taken from the peritoneal fluid and during the operation further smears were taken from the Fallopian tubes, uterine cavity and cervical canal. RESULTS: Statistically significant differences were found for large starch particles at all locations between the study and control groups examined 1 day pre-operatively. Considering small starch particles, there were significant differences in cervix (P < 0.001), uterus (P < 0.01) and the Fallopian tubes (P < 0.01). The combined results also show significant differences between both large and small starch particles in cervix, uterus and the Fallopian tubes. There were also differences between the study and control groups examined 4 days pre-operatively, but these were not statistically significant except for small and large starch particles in uterus (P < 0.01, P < 0.05) and cervix (P < 0.05, P < 0.05). CONCLUSIONS: This study has pointed out a retrograde migration of starch also in humans after a gynaecological examination with powdered gloves. Consequently, powder or any other potentially harmful substance that can migrate from the vagina should be avoided.     

Experimental infection of chimpanzees with antihemophilic (factor VIII) materials: recovery of virus-like particles associated with non-A, non-B hepatitis.

Non-A, non-B viral hepatitis was transmitted to four colony-born chimpanzees by infusion of three lots of antihemophilic factor (factor VIII) implicated in the transmission of non-A, non-B hepatitis to two human recipients. All four inoculated animals showed histopathological evidence of viral hepatitis, and all demonstrated significant ALT elevations between seven and one-half weeks after inoculation. Acute-phase plasma from one of the infected chimpanzees (no. 771) was shown to induce non-A, non-B hepatitis in two other chimpanzees approximately three weeks after their inoculation. In addition, an acute-phase open liver wedge biopsy obtained from animal no. 771 was processed and examined by immune electron microscopy (IEM) for virus-like particles with convalescent serum from a serologically confirmed case of non-A, non-B hepatitis. Twenty-five to 30 nm (mean = 27 nm) diameter virus-like particles that were either "full" or "empty" were identified in this liver preparation by IEM. Two additional chimpanzees inoculated with a cesium chloride gradient fraction of an isopycnically banded liver homogenate (animal no. 771) also developed elevated ALT activity two to two and one-half weeks later. Our findings have experimentally verified that commercially produced factor VIII materials can induce non-A, non-B hepatitis in champanzees and that the disease can be subpassaged in these animals by inoculation of either acute-phase plasma or liver. These results also provide evidence for the association of 27 nm-diameter virus-like particles with non-A, non-B viral hepatitis.     

Multiple Copies of the Upstream Regulatory Region of the Major Capsid Protein Gene of Bacteriophage MB78 Inhibit Phage Morphogenesis

The 2.311 kb EcoRI F fragment of bacteriophage MB78 has been cloned in multicopy vectors pUC19 and pCR90. Salmonella typhimurium strains carrying such plasmids cannot support development of phage MB78 while other Salmonella phages like P22 and 9NA grow normally. Most of the phage MB78 induced functions are normal in such transformed hosts but proper maturation of the phage particles does not take place. Deletion of 138 bp from the 3 end of the cloned fragment reverses the inhibitory effect. Analysis of nucleotide and the deduced amino acid sequence of a 1.2 kb HindIII-SalI fragment of the phage genome which overlaps the 138 bp confirms that this part contains the upstream regulatory region of the major structural protein gene. It seems that in presence of multiple copies of the upstream regulatory region (which includes a number of promoter like sequence) of the coat protein gene, the maturase gene is down regulated and this is effective only in cis, a situation quite similar to that of Q RNA phages.     

钛颗粒负荷对切应力作用下骨髓间质干细胞F-actin表达和DNA含量的影响

假体磨损碎屑颗粒是引起假体一骨界面无菌性炎症和骨溶解而致全关节置换术失败的主要原因之一。磨屑颗粒所诱发的骨溶解须有周围骨组织中成骨细胞分泌足够的骨基质以弥补丢失的骨量，而成骨细胞正常的数量和质量有赖于其来源骨髓祖细胞—骨髓问质干细胞的正常增殖分化能力的维持。为了探讨磨屑钛颗粒对大鼠骨髓间质干细胞(Rat MSCs，rMSCs)产生细胞毒性的可能细胞分子机制，选用健康3月龄SD雄性大鼠，采用Percoll等密度梯度离心法分离获取rMSCs，经体外传代纯化培养后，与不同直径、不同负荷浓度、不同负荷作用时间的钛颗粒悬液共孵育，再采用精准的流室系统对钛颗粒负荷的rMSCs施加一定的流体剪切应力(Fluid shear stress，FSS)后立刻固定细胞，经免疫荧光抗体染色，结合激光共聚焦显微镜技术和图像分析软件定性定量分析rMSCs F—actin表达和DNA含量的变化情况。同时设置相应的未经钛颗粒孵育的rMSCs细胞为对照组细胞。结果显示，切应力作用可上调rMSCs胞内F—actin的表达。亚微(Submieron)直径(0．9μm)的钛颗粒负荷对rMSCs F—actin表达和DNA含量的抑制作用最为显著，并伴有凋亡小体出现；直径为2．7μm的钛颗粒负荷产生的抑制作用略为减弱，而较大直径(6．9μm)的抑制效应最弱。相同条件下，钛颗粒负荷对F—actin的抑制效应有一定的时间和浓度依赖性：以0．1wt％浓度对F—actin表达和DNA含量的抑制效应最为明显，亦有凋亡小体的出现；随着浓度的降低，抑制作用亦减弱，以0．01wt％浓度最弱；随着作用时间的延长，F—actin表达和DNA含量逐渐降低，至实验中的32h达到最低值。提示：磨屑颗粒对rMSCs活力的抑制作用是假体无菌性松动的可能分子机制，对其具体细胞分子机制进行深入研究，必将有助于有效防治假体松动药物的研发应用以及人工关节材料的优化设计，从而为全关节置换术患者真正带来福音。     

Evaluation of quantitative aerosol techniques for use in bronchoprovocation studies

To investigate airway physiology by use of inhaled aerosols, it is frequently necessary to measure the actual amount of material deposited on the airway wall as well as the site of particle deposition. To satisfy these needs, radiolabeled aerosols and gamma camera techniques have been used to measure regional deposition of inhaled particles. To make quantitative measurements of the amount deposited, previous investigators have used a "phantom" technique to indirectly calibrate the gamma camera for the attenuation of gamma rays through the lungs and chest wall. For this calibration, the phantom is a simulated lung containing a known amount of radioactivity. Radioactive counts emitted from the phantom are assumed to be attenuated in the same manner as the intact human lung. The present article describes a technique to determine directly the amount of inhaled aerosol deposited in the lung and simultaneously to calibrate the gamma camera for each individual subject. We used right angle light scattering and a gamma camera to measure individual values of the deposition fraction (DF) of inhaled aerosol deposited in the lung and the coefficient of attenuation (AC) of gamma rays in normal and obstructed lungs of human subjects. Radiolabeled monodisperse aerosols 1 and 2 microns in diameter were used. Knowledge of the activity of the inhaled aerosol (microcurie per liter), the volume inhaled, and the measured DF determined each subject's AC (counts per minute per microcurie). DF varied by an order of magnitude in normal (0.04 to 0.48) and obstructed (0.16 to 0.75) of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Crystalluria in marathon runners

Summary Epidemiological evidence suggests that marathon runners have a higher incidence of renal stone formation than occurs in the general population. Since crystalluria and stone disease are thought to be related, we subjected urine samples from a group of marathon runners to particle counting and sizing in a Coulter Counter equipped with a population accessory unit. The volume-size distribution curves so obtained were bimodal with one peak occurring in the 2–5 m diameter range and a second in the 15–32 m diameter range—a pattern that is remarkably similar to the distributions reported for recurrent idiopathic stone formers and distinctly different to those recorded for control subjects. Analyses by scanning electron microscopy and X-ray powder diffraction revealed other features which are regarded as typical of stone formers' crystalluria. These physicochemical data indicate that marathon runners may be at increased risk of urinary stone formation.     

微乳液反应法制备磺胺嘧啶银均匀微晶及其最佳处方评价

目的：应用微乳液反应法制备磺胺嘧啶银均匀微晶,均匀制得的微晶的粒径大小约为2～4um,均匀微晶的结晶性好,纯度高。用均匀设计方法优化条件,制备的均匀的微晶平均粒径大小为2.09um,实验结果达到预测结果要求。结论：用微乳液反应法能获得磺胺嘧啶银均匀微晶。     

The effect of respiratory activity,non-invasive respiratory support and facemasks on aerosol generation and its relevance to COVID-19

Respirable aerosols (< 5 µm in diameter) present a high risk of SARS-CoV-2 transmission. Guidelines recommend using aerosol precautions during aerosol-generating procedures, and droplet (> 5 µm) precautions at other times. However, emerging evidence indicates respiratory activities may be a more important source of aerosols than clinical procedures such as tracheal intubation. We aimed to measure the size, total number and volume of all human aerosols exhaled during respiratory activities and therapies. We used a novel chamber with an optical particle counter sampling at 100 l.min^-1 to count and size-fractionate close to all exhaled particles (0.5–25 µm). We compared emissions from ten healthy subjects during six respiratory activities (quiet breathing; talking; shouting; forced expiratory manoeuvres; exercise; and coughing) with three respiratory therapies (high-flow nasal oxygen and single or dual circuit non-invasive positive pressure ventilation). Activities were repeated while wearing facemasks. When compared with quiet breathing, exertional respiratory activities increased particle counts 34.6-fold during talking and 370.8-fold during coughing (p < 0.001). High-flow nasal oxygen 60 at l.min^-1 increased particle counts 2.3-fold (p = 0.031) during quiet breathing. Single and dual circuit non-invasive respiratory therapy at 25/10 cm.H₂O with quiet breathing increased counts by 2.6-fold and 7.8-fold, respectively (both p < 0.001). During exertional activities, respiratory therapies and facemasks reduced emissions compared with activities alone. Respiratory activities (including exertional breathing and coughing) which mimic respiratory patterns during illness generate substantially more aerosols than non-invasive respiratory therapies, which conversely can reduce total emissions. We argue the risk of aerosol exposure is underappreciated and warrants widespread, targeted interventions.