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Characterization of huJAM: evidence for involvement in cell-cell contact and tight junction regulation.

Cell-cell interactions of the mucosal epithelia are important for the maintenance and establishment of epithelial barrier function. During events of inflammation, such cell-cell interactions are often disrupted, resulting in a leaky epithelial barrier, which in turn can lead to various inflammatory and infective dysfunctions. Human junctional adhesion molecule (huJAM), found on the mucosal epithelia and vascular endothelia of many major organ systems, is a membrane glycoprotein which resolves to a doublet band of approximately 40 and approximately 37 kDa under SDS-PAGE analysis, representing differentially glycosylated forms of the same protein. huJAM was localized to the lateral membrane of Caco-2 cells (a human colonic epithelial cell line) monolayers, in an area basolateral of the epithelial tight junctions (TJ). Through functional and biochemical assays, we show huJAM to be able to homotypically associate and to participate in TJ restitution after trypsin-EDTA disruption. Furthermore, we also observed a migration of huJAM expression toward areas of cell-cell contacts during events of cell adhesion and monolayer formation. These qualities makes huJAM a likely player in the regulation of cell-cell contacts and the subsequent formation of TJs.

Animals↗

Refocusing the immune system to react with human tumors by targeting human lymphocytes with bispecific antibodies.

Recent studies have established that crosslinking triggering sites on an immune cell, such as CD3 or FcR, to antigens on target cells with redirect the target-cell specificity of the immune cell. We are testing whether the human immune system can be refocused against human tumors with bifunctional antibodies produced by chemically crosslinking monoclonal antibodies against CD3 and tumor antigens with SPDP. The tumor model consists of immunodeficient (athymic) mice injected i.p. with a human ovarian cell line, OVCAR 3. Mice are treated 4-6 days later, after tumor growth has been established, with i.p. injections of human PBL from normal donors and bifunctional antibodies. Tumor growth is assessed by the amount of tumor cells and cell-free tumor antigen recovered in peritoneal lavage fluid 15 days after tumor injection. Relative to lymphocytes alone, bifunctional antibodies (including Fab preparations) increase the % of tumor-free mic from about 20 to 60%. A variety of controls show that both the bifunctional antibodies and the lymphocytes are required for the anti-tumor effect. Thus, heterocrosslinked antibodies can greatly enhance the anti-tumor activity in human PBL and may provide a new immunotherapeutic approach for treating human cancer.

Animals↗

Immunological cross-reactivity of enterotoxins of Aeromonas hydrophila and cholera toxin.

Pre-incubation with anticholera toxin (ACT) significantly reduced intestinal secretion induced by cell-free broth preparations of heat-labile toxins (LT) of Escherichia coli and Aeromonas hydrophila in jejunal perfusion experiments in rats in vivo. Pre-incubation with ACT also prevented cytotoxicity by E. coli LT in the Y1 cell culture system. Pre-incubation had no effect on cytotoxicity in Y1 and L132 cell lines or on haemolytic activity with cell-free preparations of A. hydrophila. In another series of experiments rats were immunized with cholera toxin given as an intraperitoneal priming dose followed 12 days later by intraduodenal boosting. Immunization significantly protected against net intestinal fluid secretion induced by enterotoxigenic E. coli and A. hydrophila and by cholera toxin.

Aeromonas↗

[Role of membrane structure in the formation of the myofibrillar system in myogenesis].

The leading role of membranes in the formation of the myofibrillar system at different stages of chick embryo development (on the 8th, 12th, 15th day) was considered. At the early stages the myofibrillar assembly depends mainly on the plasma membrane (myofibrils are located beneath the sarcolemma) and later on it depends on the developing sarcoplasmic reticulum and T-system. It was shown that transverse tubules invaginating from the plasma membrane are the framework for the forming myofibrillar system, and thin filaments are attached to the transverse tubules at the sites of future Z-lines. These results support the idea that Z-lines originate from the membrane. Destruction of the membrane elements provokes disorganization of myofibrillar contractile material.

Animals↗

[Arthroplasty of the knee. Postoperative radiologic followup].

The first generation of total knee arthroplasties (TKA) had an unacceptably high failure rate due to prosthetic design problems. The current generation closely duplicates the normal anatomy of the knee. This essay describes the normal imaging appearance. First, evaluation of TKA alignment is important. The center of the knee should lie on the mechanical axis of the leg. The width and location of lucent lines (standard system by the "Knee Society") and the height of the prosthetic joint space must be noted (wear of the polyethylene). On the AP view, the tibial component should be perpendicular in relation to the tibial or up to 2 degrees of varus alignment. On the lateral view, the tibial plateau should be horizontal or should slope downward posteriorly no more than 10 degrees. Many complications of TKA can be detected radiographically (wear, descellement, complications of the patella) and corrected to prevent prosthesis failure.

Arthroplasty, Replacement, Knee↗

A comparison between tandem and ovoids and interstitial gynecologic template brachytherapy dosimetry using a hypothetical computer model.

PURPOSE: To evaluate the dose distribution within the clinical target volume between two gynecologic brachytherapy systems---the tandem and ovoids and the Syed-Neblett gynecologic template---using a hypothetical computer model. METHODS AND MATERIALS: Source positions of an intracavitary system (tandem and ovoids) and an interstitial system (GYN template) were digitized into the Nucletron Brachytherapy Planning System. The GYN template is composed of a 13-catheter implant (12 catheters plus a tandem) based on the Syed-Neblett gynecologic template. For the tandem and ovoids, the dwell times of all sources were evenly weighted to produce a pear-shaped isodose distribution. For the GYN template, the dwell times were determined using volume optimization. The prescribed dose was then normalized to point A in the intracavitary system and to a selected isodose line in the interstitial system. The treated volume in the two systems was kept approximately the same, and a cumulative dose-volume histogram of the treated volume was then generated with the Nucletron Brachytherapy Planning System to use for comparison. To evaluate the dose to a hypothetical target, in this case the cervix, a 2-cm-long, 3-cm-diameter cylinder centered along the tandem was digitized as the clinical target volume. The location of this hypothetical cervix was based on the optimal application of the brachytherapy system. A visual comparison of clinical target coverage by the treated volume on three different orthogonal planes through the treated volume was performed. The percentage dose-volume histograms of the target were generated for comparison. Multiple midline points were also placed at 5-mm intervals away from the tandem in the plane of the cervix to simulate the location of potential bladder and rectal dose points. Doses to these normal structures were calculated for comparison. RESULTS: Although both systems covered the hypothetical cervix adequately, the interstitial system had a better coverage of the region lateral to the cervix. Smaller volumes of the vagina and uterine fundus received the full dose from the interstitial implant. The cumulative dose-volume histograms revealed larger high-dose regions within the treatment volume for the intracavitary system. The volumes receiving > or = 180% of the prescription dose were 31 cc and 17 cc for the intracavitary system and interstitial system, respectively. The isodose lines showed that most of this difference results from the high-dose region around the tandem. The percentage dose-volume histograms showed that a larger percentage of cervix received a higher dose in the intracavitary system. Fifty-two percent of the target volume received 200% or higher of the prescription dose with tandem and ovoids, compared with only 20% with the template system. Analysis of dose points outside of the 100% isodose lines showed a slightly more rapid dose drop-off with the interstitial system compared to the intracavitary system. Point doses at 20, 25, and 30 mm from the tandem in the interstitial system were 100%, 69%, and 51% of prescribed dose, and from the intracavitary system were 101%, 76%, and 58%, respectively. CONCLUSIONS: Our dosimetric analysis revealed a better coverage in the parametrial regions, but underdosage of the central cervical region, for the interstitial system. On the other hand, because of the increased distance of source to dose point, there is a more rapid dose drop-off outside the treated volume with the interstitial system, which has the potential to improve tissue sparing. Based on this analysis, we caution against using a radiotherapy system with a homogeneous central dose distribution when treating cervical cancer with an intact uterus. We recommend differential loading of the implant catheters with the majority of dose delivered from the tandem when using an interstitial GYN template with remote afterloader.

Brachytherapy↗

Lack of agreement between direct magnetic resonance imaging and statistical determination of a subthalamic target: the role of electrophysiological guidance.

OBJECT: The goal of this study was to determine the most suitable procedure(s) to localize the optimal site for high-frequency stimulation of the subthalamic nucleus (STN) for the treatment of advanced Parkinson disease. METHODS: Stereotactic coordinates of the STN were determined in 14 patients by using three different methods: direct identification of the STN on coronal and axial T2-weighted magnetic resonance (MR) images and indirect targeting in which the STN coordinates are referred to the anterior commissure-posterior commissure (AC-PC) line, which, itself, is determined either by using stereotactic ventriculography or reconstruction from three-dimensional (3D) MR images. During the surgical procedure, electrode implantation was guided by single-unit microrecordings on multiple parallel trajectories and by clinical assessment of stimulations. The site where the optimal functional response was obtained was considered to be the best target. Computerized tomography scanning was performed 3 days later and the scans were combined with preoperative 3D MR images to transfer the position of the best target to the same system of stereotactic coordinates. An algorithm was designed to convert individual stereotactic coordinates into an all-purpose PC-referenced system for comparing the respective accuracy of each method of targeting, according to the position of the best target. CONCLUSIONS: The target that is directly identified by MR imaging is more remote (mainly in the lateral axis) from the site of the optimal functional response than targets obtained using other procedures, and the variability of this method in the lateral and superoinferior axes is greater. In contrast, the target defined by 3D MR imaging is closest to the target of optimal functional response and the variability of this method is the least great. Thus, 3D reconstruction adjusted to the AC-PC line is the most accurate technique for STN targeting, whereas direct visualization of the STN on MR images is the least effective. Electrophysiological guidance makes it possible to correct the inherent inaccuracy of the imaging and surgical techniques and is not designed to modify the initial targeting.

Adult↗

Neuroblast ablation in Drosophila P[GAL4] lines reveals origins of olfactory interneurons.

Hydroxyurea (HU) treatment of early first instar larvae in Drosophila was previously shown to ablate a single dividing lateral neuroblast (LNb) in the brain. Early larval HU application to P[GAL4] strains that label specific neuron types enabled us to identify the origins of the two major classes of interneurons in the olfactory system. HU treatment resulted in the loss of antennal lobe local interneurons and of a subset of relay interneurons (RI), elements usually projecting to the calyx and the lateral protocerebrum (LPR). Other RI were resistant to HU and still projected to the LPR. However, they formed no collaterals in the calyx region (which was also ablated), suggesting that their survival does not depend on targets in the calyx. Hence, the ablated interneurons were derived from the LNb, whereas the HU-resistant elements originated from neuroblasts which begin to divide later in larval life. Developmental GAL4 expression patterns suggested that differentiated RI are present at the larval stage already and may be retained through metamorphosis.

Animals↗

Distractor modulation of saccade trajectories: spatial separation and symmetry effects.

The trajectories of saccadic eye movements can be modulated by the presence of a competing visual distractor. In the present study the trajectories of vertical saccades curved away from a single visual distractor presented in one visual field, but tended to be straight when two distractors were presented at mirror symmetric locations in both visual fields. The spatial nature of the mirror distractor effect was examined by presenting a second distractor at mirror and non-mirror locations. Saccade trajectories also tended to be straight with both mirror and non-mirror symmetrical distractors. The relationship between the distractor location and saccade curvature was examined in a third experiment by manipulating the distractor-to-target spatial separation. Although there was a tendency for greater curvature when the distractor was presented in the same hemifield as the target there was no clear relationship between curvature and distractor location. The results show that the distractor modulation of saccade trajectory is not highly spatially specific and that it can be balanced by a second bilateral distractor in the opposite visual field. The results are interpreted in terms of a model in which the initial saccade direction and curvature back towards the saccade goal are controlled by separate processes. Initial saccade direction is modulated by the inhibition of distractor locations within a 'motor map' specifying saccade direction. Curvature back towards the saccade goal may be attributed to a feedback system, with a separate representation of the visual target location, that enables an on-line correction of the saccade during mid-flight.

Adult↗

Persistent Theiler's murine encephalomyelitis virus infection in mice depends on plaque size.

Theiler's murine encephalomyelitis virus (TMEV) is an enteric pathogen of mice which causes acute and chronic neurological disorders in the natural host. When brain-derived stocks of TMEV isolates are adapted to cell culture they predominantly form either large or small plaques. In this study the type of central nervous system (CNS) infection (acute versus chronic) and the associated disease occurring in mice inoculated intracerebrally with large and small plaque strains of TMEV was investigated. Large and small plaque strains of TMEV were found to vary in virulence, type of neurological disease produced and ability to establish persistent CNS infection in mice. Two large plaque strains, GDVII and FA viruses, were highly virulent, produced acute encephalitis, but were cleared from the nervous systems of surviving animals. Therefore, it appears that these large plaque variants do not cause persistent CNS infection in mice. In contrast, five small plaque strains, DA, WW, TO4, Yale and BeAn8386 viruses, were relatively avirulent, usually produced no illness during the first month after inoculation, but readily established persistent CNS infection in mice. Persistently infected mice later developed demyelinating disease. Having identified strains of TMEV that differ regarding their ability to persist, we now hope to be able to exploit this difference in elucidating the basic mechanism(s) of TMEV persistence.

Animals↗

Testosterone regulation of the regenerative properties of injured rat sciatic motor neurons.

We have previously demonstrated that systemic administration of testosterone differentially regulates the regenerative properties of injured hamster facial motor neurons, which are androgen receptor-containing cranial motor neurons. In this investigation, the hypothesis that testosterone alters the regenerative properties of rat sciatic motor neurons, which are androgen receptor-containing spinal motor neurons, was tested using fast axonal transport of radioactively labeled proteins to assess sciatic nerve regeneration. Adult castrated male rats were subjected to crush axotomy of the sciatic nerve at the level of the gemelli tendons (mid-thigh). One-half of the axotomized animals received subcutaneous implants of testosterone propionate (TP), with the remainder of the animals sham implanted with blank capsules. The outgrowth distances of the leading axons were measured at 5, 6, 7, and 11 days postoperative. Linear regression analysis was accomplished, with the slope of the line representing the regeneration rate and the x-intercept the initial delay of sprout formation. Systemic administration of testosterone resulted in a 13% increase in the rate of regeneration, relative to the control, -TP group. Outgrowth distances were significantly increased in the +TP group only in the later stages of regeneration. However, TP did not shorten the delay in sprout formation in regenerating sciatic motor neurons, but instead produced a small prolongation in the delay time. This pattern of hormonal regulation of the regenerative properties of spinal motoneurons is similar to that previously found in cranial motoneurons. The prolongation of the initial delay may have been a factor in the lack of significant outgrowth distances during the early stages of regeneration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Cytology and immunocytochemistry of the nucleus extrolateralis anterior of the mormyrid brain: possible role of GABAergic synapses in temporal analysis.

Mormyrid fish use their electrosensory/electromotor system for both electrolocation and electrocommunication. One type of electroreceptor, the knollenorgan, has a low threshold and is used strictly for detecting a conspecific's electric organ discharge. Knollenorgan afferents terminate with mixed synapses (gap junctions and asymmetric chemical synapses) on neurons of the nucleus of the lateral line lobe (nLLL), which in turn projects to a midbrain nucleus--the nucleus extrolateralis anterior (ELa). ELa contains numerous granule cells, which are adendritic, and scattered larger neurons, here termed interstitial cells, which possess several branched dendrites. Because of the overall paucity of dendrites, the neuropil of ELa is scarcely developed and myelinated fibers predominate in between the cell bodies. Axons presumed to originate in nLLL make mixed synapses on both the interstitial and the granule cells. The interstitial neurons are immunoreactive for glutamic acid decarboxylase (GAD), the synthetic enzyme for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), while the granule cells are GAD-negative. Many GAD-positive synapses are found on each granule cell soma; at smaller densities, GAD-positive boutons also synapse on the cell bodies and dendrites of interstitial cells. The GAD-positive boutons have pleomorphic vesicles and make symmetric synapses. Such boutons presumably originate from a plexus of interstitial cell axons. Mormyrid fish use their knollenorgan afferents for precise temporal discriminations, and this information is needed for electrocommunication. The ELa, with its relatively simple neuronal circuitry, is the most likely site for precise temporal analysis in the knollenorgan afferent pathway, and we propose that the GABAergic synapses on the granule cells may be essential for accurate detection of specific time intervals.

Animals↗

A role of synchronicity of neural activity based on dynamic plasticity of synapses in encoding spatiotemporal features of electrosensory stimuli.

It is quite important for investigation of sensory mechanism to understand how dynamical property of neurons is used for encoding the feature of spatiotemporally varying stimuli. To consider concretely the problem, we focus our study on electrosensory system of a weakly electric fish. Weakly electric fish generate electric field around their body using electric organ discharge (EOD) and accurately detect the location of an object through the modulation of electric field induced by the object. We made a neural network model of electrosensory lateral-line lobe (ELL). Here we show that the features of EOD modulation depending specifically distance and size of an object are encoded into the timing of burst firing of ELL neurons. These features can be represented by the spatial area of synchronous burst firing and the interburst interval in the ELL network. We show that short-term changes of excitatory and inhibitory synapses, induced by efferent signals, regulate the ELL activity so as to effectively encode the features of EOD modulation.

Animals↗

Commercialization of veterinary viral vaccines.

If vaccines are to reliably prevent disease, they must be developed, produced and quality-controlled according to very strict regulations and procedures. Veterinary viral vaccine registrations are governed by different rules in different countries, but these rules all emphasize that the quality of the raw materials--the cells, eggs, animals or plants that are used in production--need to be carefully controlled. The veterinary vaccine business is also very cost-conscious. Emphasis over the last 5-10 years has therefore been to develop culture systems that minimize labor and sterility problems and thus provide for reliable and cost-effective production. Implementing these often more complex systems in a production environment takes considerable effort, first in scale-up trials and further down the line in convincing production personnel to change their familiar system for something new and possibly untried. To complete scale-up trials successfully, it is absolutely necessary to understand the biochemistry of the cells and the influence of the virus on the cells under scale-up and later production conditions. Once a viral product can be produced on a large scale, it is imperative that the quality of the end-product is controlled in an intelligent way. One needs to know whether the end-product performs in the animal as was intended during its conception in the research and development department. The development of the appropriate tests to demonstrate this plays an important role in the successful development of a vaccine.

Animals↗

A multicentre retrospective survey of Langerhans' cell histiocytosis: 348 cases observed between 1983 and 1993. The French Langerhans' Cell Histiocytosis Study Group.

In a retrospective study involving 32 haematology/oncology departments in France, 348 cases of Langerhans' cell histiocytosis diagnosed between 1983 and 1993 were collated. The percentage of males was 56.4%. Median age at diagnosis was 30.2 months. The median follow up was 35.5 months. Initially, 108 patients (31%) had isolated unifocal or bifocal bone involvement, 67 (19%) had isolated multifocal bone involvement, 136 (39%) had soft tissue involvement without organ dysfunction, and 37 (11%) had organ dysfunction. Two thirds of the sites of involvement diagnosed throughout the course of the disease were present at diagnosis, while the remaining one third appeared during a relapse. Treatment was tailored to the individual patient and was extremely varied, hampering any comparison of regimens. Vinblastine with or without steroids was the most common regimen when systemic chemotherapy was used for the first episode (246/348). Twenty four of the 216 patients received VP 16 as first line treatment. Two patients with progressive multiorgan relapse, despite the use of several drugs, underwent bone marrow transplantation and are alive and disease free 60 and 22 months later. Altogether 21.9% of patients had sequelae, including diabetes insipidus in 17.5% of cases. The overall survival rate is 91.7% (confidence interval 90.7 to 95%) three years after diagnosis. In the univariate analysis, age less than 1 year, ear, nose, and throat, cutaneous, lymph node, liver, spleen, lung, marrow and intestinal involvement, male sex, progressive episodes, the absence of response, and partial responses, were associated with a poor vital prognosis. In a multivariate analysis of prognostic factors, poor early outcome emerged as the most important parameter, closely linked to other poor outcome features such as young age and organ dysfunction. It identified a small number of patients with a poor initial response to treatment, for whom intensive treatment should be assessed in a phase II trial.

Adolescent↗

Xenobiotic kidney organogenesis from human mesenchymal stem cells using a growing rodent embryo.

Given the limits of allogenic organ transplantation, an ultimate therapeutic solution is to establish a self-organ from autologous stem cells and transplant them as syngrafts back into donor patients. It was reported previously that human mesenchymal stem cells (hMSC) that are cultivated in growing rodent embryos can differentiate within a spatially and temporally appropriate developmental milieu, facilitating the first step of nephrogenesis. As another step toward clinical application, the system was modified for progression to complete functional organogenesis. Rat embryos (E11.5) were isolated from uteri, and bone marrow-derived hMSC, which were transfected adenovirally with glial cell line-derived neurotrophic factor and retrovirally with LacZ, were implanted into the nephrogenic site. Forty-eight hours later, ureteric buds were elongated and initial branching was completed. The metanephroi were dissected out, developed further using in vitro organ culture for 24 h, transplanted into the omentum of a uninephrectomized rat, and grown for 2 wk. They enlarged and exhibited normal kidney structure and ultrastructure. hMSC-derived LacZ-positive cells were identified throughout the regenerated kidney and were morphologically identical to resident renal cells. Transplantation of developing metanephroi into the LacZ transgenic rat revealed that neo-kidney vasculature originated from the host circulation. Finally, fluid was collected from expanded ureters, and urea nitrogen and creatinine were measured. Levels were much higher in these fluids compared with transplanted rat sera (840.3 +/- 184.6 versus 30.4 +/- 10.8 and 10.1 +/- 3.1 versus 0.3 +/- 0.2 mg, respectively), suggesting that the neo-kidney may produce urine. Taken together, these findings suggest that hMSC can differentiate into a mature renal structure with the potential to replace lost kidney function.

Animals↗

Registration of spontaneous photon emission from virus-infected cell cultures: development of experimental system.

Detection of spontaneous photon emission from virus-infected cells was attempted using cell monolayer cultures prepared from the established cell lines differing by origin and sensitivity to viruses. The experimental system was elaborated permitting maintenance of the cell monolayer cultures grown upon quartz slides placed inside quartz cuvettes within the photomultiplier chamber during prolonged time periods (till 24-36 hr) covering the whole virus multiplication cycle. Rich nutritive medium was employed, providing undisturbed cell viability and virus-induced cytopathic effect (CPE) development during such prolonged experiment, each ingredient of the medium being checked as potential parasitic emitter or extinguisher of the cell-specific emission. As presupposed 'positive control', the in vivo cultivated chorio-allantoic membranes (CAM) of 10-days-old chick-embryonated eggs were used. The virus-infected CAMs showed specific peculiarities of the emission dynamics as compared to monotonous dynamics shown by non-infected CAMs. Similar dynamic regularities were observed in cell monolayer cultures containing much lesser (by order) number of cells per exposed sample. Using the elaborated system, some specific changes in the virus-infected cells were found, being correlated with two stages of virus replication cycle: the initial stage, synchronous penetration of the pre-adsorbed virus inside the cell, and a later stage, characterized by intensive CPE manifestations.

Animals↗

Scanning electron microscopy of the ventricular system in normal and hydrocephalic rabbits. Preliminary report and atlas.

The author used the scanning electron microscope to study the ependyma in six control rabbits and six rabbits made hydrocephalic by infusion of silicone oil into the cisterna magna. The ependymal lining of the third ventricle, head of the caudate nucleus, superior angle of the caudate, and atrium of the lateral ventricle was examined. In the hydrocephalic animals, clusters of cilia emanating from the ependyma over periventricular white matter become separated; the author believes this is secondary to ingrowth of new ependymal cell processes covered with microvilli. The addition of these cells to the ependymal surface permits ventricular dilatation without ependymal disruption and provides more surface containing microvilli, presumably capable of increased transventricular fluid transfer. No such changes occur over gray matter masses since their surfaces are not deformed by moderate ventricular dilatation. The morphological alterations in the ependyma that occur in moderate hydrocephalus do not appear to be simply manifestations of ependymal destruction but rather suggest a modification in its function from that of a surface capable of propelling cerebrospinal fluid to one capable of increased transfer of transventricular fluid. As hydrocephalus progresses, compensation may fail because of the relative decrease in microvilli so that the cell surface provides a less efficient mechanism for absorption.

Animals↗