Time-resolved microfocused small-angle X-ray scattering investigation of the microfluidic concentration of charged nanoparticles

We describe the concentration process of a dispersion of silica nanoparticles undergoing evaporation in a dedicated microfluidic device. Using microfocused small-angle X-ray scattering, we measure in time and space both the concentration field of the dispersion and its structure factor. We show that the electrostatic interactions affect the concentration rate by strongly enhancing the collective diffusion coefficient of the nanoparticle dispersion. En route towards high concentrations, the nanoparticles eventually undergo a liquid-solid phase transition in which we evidence crystallites of micron size.

Molecular diversity of bacteria in Yunnan yellow cattle (Bos taurs) from Nujiang region, China

The rumen content of four Yunnan Yellow Cattle (Bos taurs) were collected to determine the bacteria diversity by using 16S rRNA gene sequence analysis. A total of 129 sequences were examined and the sequences were referred as 107 OTU (Operational Taxonomy Unit) according to the similarity level of 97% in gene sequence. Similarity analysis revealed that Yunnan Yellow Cattle had 12 sequences (10 OTU) shared 97% or greater similarity with cultured rumen bacteria Butyrivibrio fibrisolvens, Succiniclasticum ruminis, Ruminococcus bromii, Clostridium proteoclasticum, Ruminococcus flavefaciens, Pseudobutyrivibrio ruminis, Jeotgalicoccus psychrophilus, and Prevotella ruminicola, which accounting for 9.3% of the total clones (9.2% of the total OTU). The further 12 sequences (9 OTU) shared 90-97% similarity with cultured bacteria Clostridium aminobutyricum, butyrate-producing bacterium, Schwartzia succinivorans, Prevotella ruminicola, Eubacterium ruminantium, Ruminococcus albus, and Clostridium termitidis, also accounting for 9.3% of the total sequences (8.3% of the total OTU). The remaining 105 sequences (90 OTU) shared less than 90% similarity with cultured bacteria, accounting for 81.4% of the total sequences (82.5% of the total OTU). According to the phylogenetic analysis, all sequences were phylogenetically placed within phyla of low G+C subdivision (accounting for 72.1 and 72.5% of the total clones and OTU, respectively) and CFB subdivision (Cytophaga-Flexibacter-Bacteroides; accounting for 27.9 and 27.5% of the total clones and OTU, respectively). Among the examined clones, rare bacteria Jeotgalicoccus psychrophilus was detected in the rumen of cattle.

Assessment of protozoa in Yunnan Yellow cattle rumen based on the 18S rRNA sequences

Library of ruminal protozoal 18S rRNA of Yunnan Yellow Cattle has been constructed in the present study. Phylogenic analysis of sequences was meanwhile employed to reveal the diversity of protozoa in the rumen of Yunnan Yellow Cattle. One Yellow Cattle was fed malt meal (YCRPB) and the other was fed wheat straw (YCRPS). A protozoa-specific primer (P-SSU-342f) and a eukarya-specific primer (Medlin B) were used to amplify a 1,360-bp fragment of DNA encoding protozoal small subunit (SSU) ribosomal RNA from rumen fluid. The results showed as follows: A total of 121 clones were obtained and fell into four genera identified as Entodinium (66.9%), Dasytricha (5.8%), Isotricha (9.1%), and Diplodinium (18.2%). Within the genus Entidinium, 48 of the YCRPB sequences and 33 of the YCRPS sequences clustered with the Entodinium caudatum. 7 of the YCRPB sequences were phylogenetically placed within the genus Dasytricha. 11 of the YCRPB sequences were related with high confidence to Isotricha intestinalis. 22 of the YCRPS sequences were phylogenetically placed within the genus Diplodinium. The predominant protozoal genus identified in the rumen fluid belonged to the Entodinium group, and the divergences between two cattle may due to diet and individual differences.

Dysregulation of macrophage signal transduction by Toxoplasma gondii: past progress and recent advances

The opportunistic protozoan parasite Toxoplasma gondii is well known as a strong inducer of cell-mediated immunity, largely as a result of proinflammatory cytokine induction during in vivo infection. Yet, during intracellular infection the parasite suppresses signal transduction pathways leading to these proinflammatory responses. The opposing responses are likely to reflect the parasite's need to stimulate immunity allowing host survival and parasite persistence, and at the same time avoiding excessive responses that could result in parasite elimination and host immunopathology. This Review summarizes past and present investigations into the effects of Toxoplasma on host cell signal transduction. These studies reveal insight into the profound suppression of proinflammatory cytokine responses that occurs when the parasite infects macrophages and other cells of innate immunity.

CCR2-dependent intraepithelial lymphocytes mediate inflammatory gut pathology during Toxoplasma gondii infection

Mice of the C57BL/6 strain develop acute ileal inflammation after infection with the protozoan parasite Toxoplasma gondii. This pathology resembles many key features of human Crohn's disease, including a Th1 cytokine profile with high levels of interferon gamma (IFN-gamma), interleukin 12 (IL)-12, and tumor necrosis factor alpha (TNF)-alpha, presence of pathogenic CD4(+) T cells, and infiltration of gut flora into inflammed tissue. Using CCR2(-/-) mice, we identify a role for this chemokine receptor in the pathogenesis of inflammatory pathology during T. gondii infection. Lack of chemokine (C-C motif) receptor 2 (CCR2) was associated with low levels of CD103(+) T lymphocytes in the intraepithelial compartment, Peyer's patch, and lamina propria relative to wild-type animals. Adoptive transfer of wild-type, but not IFN-gamma(-/-), intraepithelial T lymphocytes converted CCR2 knockout mice from a resistant to susceptible phenotype with respect to parasite-triggered inflammatory gut pathology. These results for the first time show a role for intraepithelial T lymphocytes in pathogenesis of ileitis triggered by a microbial pathogen.

Microfluidic exploration of the phase diagram of a surfactant/water binary system

We investigate the behavior of a binary surfactant solution (AOT/water) as it is progressively concentrated in microfluidic evaporators. We observe in time a succession of phase transitions from a dilute solution up to a dense state, which eventually grows and invades the microchannels. Analyzing these observations, we show that, with a few experiments and a limited amount of material, our microdevices permit a semiquantitative screening of the equilibrium phase diagram as well as a few kinetic observations.

Impact of different pressures and exposure times of a simulated carbon dioxide pneumoperitoneum environment on proliferation and apoptosis of human ovarian cancer cell lines

BACKGROUND

This study aimed too evaluate the proliferation and apoptosis of human ovarian cancer cell lines HO8910 and SKOV3 after exposure to a simulated laparoscopic carbon dioxide (CO2) pneumoperitoneum environment at different pressures and lengths of exposure time.

METHODS

The effects of the simulated laparoscopic CO2 pneumoperitoneum environment at different CO2 pressures (0-16 mmHg) and exposure times (1-4 h) on tumor cell growth and apoptosis were assessed by 3-[4,5-Dimethylthiazol]-2; 5-diphenyltetrazolium bromide (MTT) chromometry and proliferative index (PI) staining or Annexin V and PI double-staining flow cytometry. Cells cultured in a standard environment were used as the control group.

RESULTS

In this study, HO8910 cell growth tended to slow down with the increase in CO2 pressure and exposure time. A significantly lower PI was observed at 72 h of culture after exposure to both 8 and 16 mmHg of pressure, as compared with the control and 0 mmHg pressure group (p < 0.05). The PI of SKOV3 cells tended to decline after exposure. Significantly lower PI was observed in the group with exposure to 16 mmHg for 4 h over a 72-h period, as compared with the control groups exposed to 0 mmHg (p < 0.05). The inhibition of cell growth was associated with an increase in the proportion of cells at stage G1. The apoptotic index and the percentage of apoptotic cells tended to increase with an increase in pressure and a prolonged time of exposure.

CONCLUSIONS

The results suggest inhibited cell proliferation and increased cell apoptosis of human ovarian cancer cells were positively related to CO2 pressure and exposure time.

Carcinosarcoma arising from atypical endometriosis in a cesarean section scar

Malignant change of endometriosis in a cesarean scar (CS) is rare. We report a case of carcinosarcoma arising from atypical endometriosis in a CS scar, which was successfully treated with complete excision of the lesion and repair of the abdominal wall defect with autologous skin-muscle flap graft. A 41-year-old woman presented with a recurrent endometriosis in a CS scar. Within 16 years it changed from benign to atypical endometriosis and finally to carcinosarcoma after three operations. Complete excision of the tumor was performed, with a big defect of abdominal wall successfully repaired by autologous pedicle skin-muscle graft. The diagnosis of carcinosarcoma arising from atypical endometriosis was confirmed histologically. The lesion recurred 6 months after the fourth operation. She died of disease 15 months after the fourth operation. This case demonstrated that long-standing recurrent scar endometriosis could undergo malignant changes and should be made aware. The primary treatment is complete surgical excision.

New York City syndromic surveillance systems

New York City's first syndromic surveillance systems were established in 1995 to detect outbreaks of waterborne illness. In 1998, daily monitoring of ambulance dispatch calls for influenza-like illness began. After the 2001 World Trade Center attacks, concern about biologic terrorism led to the development of surveillance systems to track chief complaints of patients reporting to emergency departments, over-the-counter and prescription pharmacy sales, and worker absenteeism. These systems have proved useful for detecting substantial citywide increases in common viral illnesses (e.g., influenza, norovirus, and rotavirus). However, the systems have not detected more contained outbreaks earlier than traditional surveillance. Future plans include monitoring school health and outpatient clinic visits, augmenting laboratory testing to confirm syndromic signals, and conducting evaluation studies to identify which of these systems will be continued for the long term.

Evaporation of liquids and solutions in confined geometry

We describe a drying setup where a liquid droplet is confined between two circular glass plates and allowed to evaporate. Optical imaging of the shrinking droplet provides the temporal evolution of the solvent volume. For a pure liquid, we measure the diffusion coefficient of the evaporating gas with a good accuracy. For a solution, the slowing down of evaporation by progessive concentration of the solute yields a direct measurement of the solvent activity.

Endobronchial eosinophils preferentially stimulate T helper cell type 2 responses

BACKGROUND

Antigen-loaded eosinophils instilled intratracheally into mice were capable of migrating into local lymph nodes and localize to the T cell-rich paracortical zones where they stimulated antigen-specific proliferation of CD4+ T cells. The aim of the present study was to evaluate whether eosinophils within the tracheobronchial lumen can stimulate Th2 cell expansion by presenting antigen both in vitro and in vivo.

METHODS

Airway eosinophils were recovered from ovalbumin-sensitized and -challenged BALB/c mice, these eosinophils were then co-cultured with sensitized CD4+ cells in the absence or presence of anti-CD80 or/and -CD86 monoclonal antibodies. Airway eosinophils were instilled into the trachea of sensitized mice. At 3 days thereafter, the draining paratracheal lymph nodes were removed and teased into cell suspensions for culture. Cell-free culture supernatants were collected for detection of cytokines.

RESULTS

Our data showed that airway eosinophils functioned as CD80- and CD86-dependent antigen-presenting cells (APCs) to stimulate sensitized CD4+ lymphocytes to produce interleukin (IL)-4, IL-5, and IL-13, but not interferon (IFN)-gamma in in vitro assay. When instilled intratracheally in sensitized recipient mice, airway eosinophils migrated into draining paratracheal lymph nodes primed Th2 cells in vivo for IL-4, IL-5, and IL-13, but not IFN-gamma, production during the in vitro culture that was also CD80- and CD86-dependent.

CONCLUSION

Eosinophils within the lumina of airways could process inhaled antigen function in vitro and in vivo as APCs to promote expansion of Th2 cells. This investigation highlights the potential of eosinophils to not only act as terminal effector cells but also to actively modulate immune responses by amplifying Th2 cell responses.

Kinetics of the micelle-to-vesicle transition: aqueous lecithin-bile salt mixtures

Important routes to lipid vesicles (liposomes) are detergent removal techniques, such as dialysis or dilution. Although they are widely applied, there has been only limited understanding about the structural evolution during the formation of vesicles and the parameters that determine their properties. We use time-resolved static and dynamic light scattering to study vesicle formation in aqueous lecithin-bile salt mixtures. The kinetic rates and vesicle sizes are found to strongly depend on total amphiphile concentration and, even more pronounced, on ionic strength. The observed trends contradict equilibrium calculations, but are in agreement with a kinetic model that we present. This model identifies the key kinetic steps during vesicle formation: rapid formation of disk-like intermediate micelles, growth of these metastable micelles, and their closure to form vesicles once line tension dominates bending energy. A comparison of the rates of growth and closure provides a kinetic criterion for the critical size at which disks close and thus for the vesicle size. The model suggests that liposomes are nonequilibrium, kinetically trapped structures of very long lifetime. Their properties are hence controlled by kinetics rather than thermodynamics.

[Endometriosis in adolescents: analysis of 6 cases]

OBJECTIVE

To review the diagnosis and treatment of endometriosis in adolescents and to evaluate the surgical and medical treatment options for this special population.

METHOD

To review the 6 cases of adolescent endometriosis and to review the literature research.

RESULTS

Three hundred and ninety nine cases under age 18 had undergone gynecological operation. So the incidence among this period is 1.8% (6/339) in hospitalized adolescents. Four cases have complicated genital tract anomalies. Preoperative diagnosis is rare. Good prognosis is expected in most patients. Only 1 case relapsed 9 years after medical therapy. Endometriosis is the most common cause of chronic pelvic pain in adolescents. There may be a natural progression of endometriosis from atypical lesions in adolescents to classic lesions in adults. Congenital abnormalities of the reproductive tract are the main reason for the adolescent endometriosis.

CONCLUSIONS

Endometriosis should be strongly suspected in adolescent with chronic pelvic pain especially with no response to oral contraceptives and nonsteroidal antiinflammatory medicine. The treatment involves the surgical operation and medicine. Adolescence;

Laparoscopic myomectomy

OBJECTIVE

To investigate the indications, surgical techniques and complications of laparoscopic myomectomy.

MATERIALS AND METHODS

A retrospective study was carried out in 74 patients with fibroids > 3 cm from March, 1995 until May, 2000 at PUMC Hospital. Indications for surgery were symptomatic fibroids (20 cases), mainly pain or urine frequency; progressively increasing fibroid size (7 cases); coexistent adnexal pathology(26 cases) and infertility(21 cases).

RESULTS

The number of fibroids of each patient varied from 1 to 4 with single fibroid of 62 cases (83.7%). The fibroids were located in anterior wall (30 cases), posterior wall (23 cases) and fundus (21 cases). A total of 93 fibroids were removed from these patients including 16 intramural fibroids and 77 subserous fibroids. The size of dominant fibroids ranged from 3 approximately 8 cm (mean 4.8 cm). In 19 cases (25.6%), the uterine wall was sutured in one layer. Mean duration of operation was 73 minutes and mean blood loss was 82 ml. Longer operating time and more blood loss were observed in patients with fibroids > or = 4 cm than those with fibroids < 4 cm. The difference was statistically significant ( P < 0.05). Mean postoperative hospital stay was 3.2 days and overall complication rate was 1.4%. The average postoperative follow-up period was 22 months (1 approximately 62 months). All the patients with symptoms showed remission of their complaints at 2-month follow-up. Recurrence of fibroid occurred in 1 case 1 year after initial operation and second laparoscopic myomectomy was given to her successfully. Five patients became pregnant. The pregnancy was uneventful and proceeded to selective caesarean section at term pregnancy in 4 cases. One miscarriage occured at 8 weeks in the 5th case. No adhesions at myomectomy site were found in these 5 patients.

CONCLUSIONS

Our study suggests the feasibility of laparoscopic myomectomy in selected patients, which leads to effectiveness, low complication rate and satisfactory remission of symptoms. Further study on recurrence and fertility must be continued.

[Complications in laparoscopic gynecologic surgery: analysis of 34 cases]

OBJECTIVE

To investigate retrospectively the complication rate of gynecological laparoscopies at Peking union medical college (PUMC) hospital over 6-year period.

METHODS

1,769 laparoscopic surgeries were carried out from Jan. 1994 through Oct. 1999. The procedures included 1,421 adnexal surgeries, 52 myomectomies and 296 laparoscopic assisted vaginal hysterectomy (LAVH). Complication was defined as an event that had modified the usual course of the procedure or of the postoperative period.

RESULTS

Complications occurred in 34 cases, the overall complication rate was 1.9%. Unintended laparotomies occurred in 6 cases (0.3%). Complication rate was 0.9%, 1.9% and 6.8% in adnexal surgeries, myomectomies and LAVH respectively. 12 (35.3%) complications related to puncture and pneumoperitoneum, including five severe emphysema, 7 injuries to epigastric blood vessels of abdominal wall and omental blood vessel, this figure represented 35.3% of all complications of this series. 5 (14.7%) intraoperative, complications occurred during the laparoscopic surgery (3 severe bleedings, 1 bladder injury and 1 skin burn of leg related to the electrode plate), laparotomy was required in 4 of these cases. 17 (50.0%) complications occurred during postoperative stage: 2 intraperitoneal hemorrhages needing re-laparotomy, 2 bowel complications, 4 nerve paresis and 9 febrile morbidities.

CONCLUSIONS

In our experience, operative gynecologic laparoscopy is associated with acceptable morbidity rate, but can not be overlooked. Complications seems related to advanced procedures such as LAVH.

Oscillating viscosity in a lyotropic lamellar phase under shear flow

We report some time-dependent behavior of lyotropic lamellar phase under shear flow. At fixed stress, near a layering instability, the system presents an oscillating shear rate. We build up a new stress versus shear rate diagram that includes temporal behavior. This diagram is made of two distinct branches of stationary states which correspond, respectively, to disordered and ordered multilamellar vesicle phases. When increasing the shear stress, prior to the transition to the ordered structural state, sustained oscillations of the viscosity are recorded. They correspond to periodic structural change of the entire sample between a disordered and a ordered state of multilamellar vesicles.

Complications in laparoscopic gynecologic surgery

OBJECTIVE

To investigate retrospectively the complications and associated factors of gynecolgical laparoscopies.

METHODS

1 769 laparoscopic surgeries were carried out from January 1994 to October 1999 at our department. The procedures included 1421 surgeries of ovary and tube, 52 myomectomies and 296 cases of laproscopic-assisted vaginal hysterectomy (LAVH). A total of 312 patients had a history of prior laparotomy (17.6%).

RESULTS

Complications occured in 34 cases, the overall complication rate was 1.92%. Unintended laparotomies occured in 6 cases (0.34%). 12 complications were associated with insertion of Veresse needle or trocar and creation of pneumoperitoneum, including 5 severe emphysema and 7 vascular injuries, this figure represents 35.3% of all complications of this series. Five intraoperative complications (14.7%) occured during the laparoscopic surgery (3 severe bleedings, one bladder injury and one skin burn of leg caused by damaged electrode plate), laparotomy was required in four of these cases. Seventeen complications occured during postoperative stage: 2 intraperitoneal hemorrhages needing laparotomy, 2 bowel injuries, 4 nerve paresis and 9 febrile morbidities.

CONCLUSIONS

Operative gynecologic laparoscopy is associated with acceptable morbidity rate, but can not be overlooked. Complication rate seems to be higher in advanced procedures such as LAVH.

Determination of matrix metalloproteinase activity using biotinylated gelatin

Matrix metalloproteinases (MMPs) and, specifically, MMP-2 (gelatinase A) and MMP-9 (gelatinase B) are strongly associated with malignant progression and matrix remodeling. These enzymes are a subject of intensive studies involving screening of comprehensive chemical libraries of synthetic inhibitors. There is no simple method available for measurement of activity of gelatinases and related MMPs. Here, we report a simple, inexpensive, and highly sensitive assay for MMP activity. The assay performed in a 96-well microtiter plate format employs biotin-labeled gelatin (denatured collagen type I) as a substrate. Following the substrate cleavage, only the proteolytic fragments bearing biotin moieties are captured by streptavidin coated on the plastic surface and the captured fragments with at least two biotin molecules should be revealed by streptavidin conjugated with horseradish peroxidase. The frequency of lysine residues is low in collagen type I relative to the MMP cleavage sequences (PXGX). Accordingly, the majority of the cleavage products must be devoid of biotin or possess only one biotin group. Both of these types of fragments cannot be recognized by the horseradish peroxidase-streptavidin conjugate. Therefore, higher gelatinolytic activity is associated with lower signal in the assay. This 2-h assay allows identification of gelatinolytic activity of MMP-2 in concentrations as low as 0.16 ng/ml. The sensitivity of this ELISA-like assay is comparable to that of gelatin zymography, a method widely used to detect gelatinases. However, in contrast to zymography, the assay directly measures the enzymatic activity of MMP samples. The gelatinolytic activity assay permits efficient analyses and screening of the MMP inhibitor panels and allows quantitation of gelatinolytic activity of various MMPs in solution as well as on cell surfaces.