Prevention of retrosternal adhesion formation in a rabbit model using bioresorbable films of polyethylene glycol and polylactic acid

The purpose of this study was to test the efficacy of three bioresorbable films of polyethylene glycol (EO) and polylactic acid (LA) (EO/LA = 1.5, 2.5, and 3.0) in the prevention of adhesion formation between the epicardium and the sternum (retrosternal adhesions) in a rabbit model. Retrosternal adhesions were generated by sternotomy, pericardiotomy, and abrasion of the anterior epicardium. The adhesion barrier was placed between the epicardium and the sternum and sutured to the edge of the pericardium. Epicardial adhesions were evaluated 14-20 days later by assessing the area of the epicardium covered by adhesions. In the control rabbits, tenacious adhesions were observed between sternum and the central portion of epicardium (portion exposed through the pericardiotomy) which were difficult to dissect. When a bioresorbable film was placed over the pericardium, adhesion formation at the central strip of the epicardium (area between the sternum and the epicardium exposed through the pericardium) could be reduced or prevented. At this site, the areas of adhesion formation were 0% (EO/LA = 1.5), 8.4 +/- 2.8% (EO/LA = 2.5), and 5.6 +/- 4.7% (EO/LA = 3.0) of the central strip, significantly less than that observed in the control group, 78.0 +/- 5.8% (P < 0.01). At the anterior left and right and posterior apex of the heart (sites where the film was not placed), there were no differences between control and treatment groups. The films were completely resorbed at the time of necropsy in group EO/LA = 2.5 and 3.0. Small pieces of film were observed in group EO/LA = 1.5. In conclusion, the bioresorbable films [EO/LA = 1.5 (REPEL-CV), 2.5, or 3.0] were efficacious in the reduction of retrosternal adhesions to the epicardium.

[A case of multiple sclerosis with initial symptoms of narcolepsy]

We reported a 13-year-old boy diagnosed as multiple sclerosis associated with narcolepsy. He had suffered from retrobulbar optic neuritis at the age of 11 years which was improved gradually by prednisolone. Four months later he was admitted because of excessive somnolence. The diagnosis of narcolepsy was made based on hypnagogic hallucination, sleep paralysis, changes of personality and the sleep onset sREM (SOREM). The elevation of anti-measles antibody and a positive oligoclonal band in CSF, low density areas in the bilateral internal capsule on CT scan, and high signal areas in the same region on T2-weighted MRI confirmed the diagnosis of multiple sclerosis. An abnormal arousal response occurred occasionally in sleep stage 2 and 4, which started with electrical silence followed by a period with irregular high voltage slow waves and repetitive focal spike train. Those clinical symptoms and abnormalities of biochemical and electrophysiological studies normalized after treatment with prednisolone. However, abnormalities on MRI showed no improvement even after long term administration of prednisolone (2.5 mg/day).

Poststreptococcal reactive arthritis: clinical characteristics and association with HLA-DR alleles

OBJECTIVE

To assess the relationship of poststreptococcal reactive arthritis (ReA) to other forms of ReA and rheumatic fever by comparing the frequency of HLA-B27 and DRB1 alleles in these diseases.

METHODS

The diagnosis of poststreptococcal ReA was established in 25 children seen in a pediatric rheumatology clinic. HLA-B27 and DRB1 genotyping was performed in 18 of the white American patients. The DRB1 genotyping results were compared with those in 33 patients with rheumatic fever and 190 normal individuals.

RESULTS

HLA-B27 was positive in 3 of the 18 poststreptococcal ReA patients, a frequency not different from that found in normal individuals. Compared with normal controls, the frequency of the DRB1*01 allele was higher in poststreptococcal ReA patients (odds ratio [OR] 2.7, P=0.044), while DRB1*16 was increased in patients with rheumatic fever (OR 4.3, P=0.028).

CONCLUSION

The association of poststreptococcal ReA with HLA-DRB1*01, but not with HLA-B27, suggests that its pathogenesis may be more similar to that of rheumatic fever than to that of ReA associated with enteric pathogens.

The effect of systemic tetracycline on resorption of dried replanted dogs' teeth

The use of systemic penicillin after an avulsion injury has been recommended to decrease the occurrence of resorption complications. Tetracycline antibiotics have been reported to possess anti-resorptive properties in addition to their anti-microbial actions. The purpose of this study was to evaluate histologically the effect of systemically administered tetracycline and amoxicillin on the inhibition of resorption due to attachment damage after replantation of dogs' teeth. Thirty-one roots from the teeth of four beagle dogs were endodontically treated to inhibit subsequent inflammatory root resorption of pulpal origin. They were then extracted and left to bench dry for 1 h to ensure severe periodontal ligament damage before replantation. For the teeth in the experimental groups, two dogs were given tetracycline hydrochloride and the other two dogs were given amoxicillin, administered orally, on the day of extraction/replantation and for the following 6 days. The control group were teeth in these animals treated in the same manner but where no antibiotics had been given. After 12-16 weeks, the dogs were sacrificed and histological sections were prepared and evaluated for complete healing, inflammatory and replacement root resorption, and the groups were compared. It was shown that healing in the amoxicillin and the control groups was poor (10.90% and 11.28%, respectively), while for the tetracycline group, 35.45% showed complete healing. Individual teeth with over 50% complete healing sites were considered as having good healing, and significantly more of these teeth were found in the tetracycline group (5 of 11 teeth) compared to the amoxicillin (1 of 11 teeth) or control group (1 of 8 teeth).

The effect of mivacurium pretreatment on intra-ocular pressure changes induced by suxamethonium

Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied in a double-blind, randomised, placebo-controlled study evaluating the efficacy of mivacurium pretreatment in attenuating the rise in intra-ocular pressure in response to suxamethonium administration, laryngoscopy and intubation. The patients were randomly allocated to receive either mivacurium 0.02 mg.kg-1 or normal saline as pretreatment 3 min before a rapid sequence induction technique using alfentanil, propofol and suxamethonium. Suxamethonium induced a significant increase in intra-ocular pressure in the control group but not in the mivacurium pretreatment group (mean (SEM) increase = 3.5 (1.2) mmHg vs. 0.4 (0.8) mmHg, p < 0.05). There was a decrease in intra-ocular pressure in both groups after laryngoscopy and intubation with no significant difference between the two groups. These results show that mivacurium pretreatment is effective in preventing the increase in intra-ocular pressure after suxamethonium administration.

Cardiac graft intercellular adhesion molecule-1 (ICAM-1) and interleukin-1 expression mediate primary isograft failure and induction of ICAM-1 in organs remote from the site of transplantation

During the first few hours after heart transplantation, the occurrence of graft failure is unpredictable and devastating. An explosive cascade of inflammatory events within the reperfused graft vasculature is likely to be mediated, at least in part, by the local expression of the leukocyte adhesion receptor intercellular adhesion molecule-1 (ICAM-1, CD54). Furthermore, although proinflammatory cytokines such as interleukin-1 (IL-1) are known to autoinduce their own (and ICAM-1) expression in vitro, there are no data to identify their functional in vivo cross talk in the setting of isograft transplantation. To determine the role of ICAM-1 in primary graft failure, we used an isogeneic vascularized model of heterotopic cardiac transplantation. ICAM-1 mRNA and protein increased in grafts during the early posttransplant period and were predominantly localized in the endothelium. The functional significance of this was established using donor hearts obtained from either ICAM-1-deficient (ICAM-1 -/-) or control (ICAM-1 +/+) mice. ICAM-1 +/+ grafts exhibited increased neutrophil infiltration, reduced left ventricular compliance, and poorer survival than did ICAM-1 -/- grafts. Increased ICAM-1 expression was not limited to ICAM-1 +/+ grafts but also occurred in unmanipulated recipient organs located remote from the site of surgery (but only after transplantation of ICAM-1 +/+, not ICAM-1 -/-, cardiac grafts). This expression of ICAM-1 in remote organs appeared to be triggered by IL-1alpha released from the graft, because (1) in situ hybridization revealed increased IL-1 mRNA within cells of the reperfused graft, including myocytes and endothelial cells; (2) ICAM-1 expression in remote organs coincided with a significant increase in serum levels of IL-1alpha after transplantation of ICAM-1 +/+ grafts; both remote organ ICAM-1 expression and IL-1alpha levels were blunted by implantation of ICAM-1 -/- grafts; and (3) remote organ ICAM-1 expression and neutrophil infiltration and IL-1 levels could be blocked by the administration of an IL-1 receptor antagonist. These data demonstrate an apparent positive-feedback loop in which local ICAM-1 and IL-1 expression leads to a mutual amplification of each other's expression within the reperfused graft, promulgating inflammatory events that are likely to be an important cause of primary cardiac graft failure. Because IL-1 receptor blockade reduces the IL-1-mediated autoinduction of IL-1, reduces the expression of ICAM-1 in both the graft and remote organs, and improves graft survival, it may provide a new and effective strategy to prevent the occurrence of primary cardiac graft failure.

Analysis of Puerariae radix and its medicinal preparations by capillary electrophoresis

This study presents a high-performance capillary electrophoresis (CE) method to analyze five constituents of Puerariae radix, an important crude herb used in Chinese medicine. Puerarin, daidzin, daidzein, genistein and biochanin A are the bioactive constituents of Puerariae radix. Herein, those analytes were successfully separated within 6 min using a pH 10.1 borax-NaOH buffer. The effects of pH value and concentration of the running buffer on the separation of the five analytes were also examined. The relative standard deviations of the analytes' migration times were less than 0.38% under the optimized separation conditions. Notably, the correlation coefficients of the analytes' linear calibration graphs exceeded 0.998. Moreover, the amounts of the five constituents in three different Puerariae radix samples were determined by the CE method with a relatively simple extraction procedure.

Cloning and characterization of glial cell line-derived neurotrophic factor receptor-B: a novel receptor for members of glial cell line-derived neurotrophic factor family of neurotrophic factors

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor with diverse biological functions. Signal transduction of GDNF is mediated by binding to a glycosyl-phosphatidylinositol (GPI)-linked receptor GDNFR-alpha and activation of c-RET tyrosine kinase. The recent discovery of a new GDNF homolog neurturin raises the possibility that multiple receptors exist for the members in the GDNF family. Here we report isolation of the gene encoding a new receptor called GDNFR-beta. Sequence analysis indicated that GDNFR-beta is also a GPI-linked protein, with 47% identity to GDNFR-alpha. The GDNFR-beta transcript was preferentially expressed in the brain, spleen and lung, but moderate levels of GDNFR-beta mRNA were also found in kidney and the entire gastrointestinal track. In situ hybridization revealed high expression levels in the entorhinal cortex and olfactory bulb, followed by cortex, septum, inferior and superior colliculus, and zona inserta. A laminar pattern of expression was detected in layer III of the cortex. Treatment with GDNF of PC12 cells transfected with the GDNFR-beta gene activated mitogen-activated protein kinase (MAPK) and elicited neurite outgrowth. GDNFR-alpha and GDNFR-beta together form a new family of GPI-linked receptors for GDNF-like molecules.

Sialadenoma papilliferum of the esophagus

Sialadenoma papilliferum is an extremely rare benign tumor of the esophagus. We report a 70-yr-old woman who was first thought to have adenocarcinoma in the distal esophagus. Transhiatal esophagectomy and left colon interposition were performed. The pathological diagnosis of sialadenoma papilliferum of the esophagus arising in the submucosal gland ducts was confirmed after surgery.

Controlled release microparticles as a single dose diphtheria toxoid vaccine: immunogenicity in small animal models

Diphtheria toxoid (DT) was encapsulated in microparticles prepared from polylactide-co-glycolide (PLG) polymers using a solvent evaporation technique. Combinations of small and large sized microparticles with controlled release characteristics were used to immunize Sprague Dawley rats and the antibody responses were monitored for one year. For comparison, control groups of rats were immunized at 0, 1 and 2 months with DT adsorbed to alum. The antibody responses generated by the microparticles were comparable to the alum immunized control groups from 32 weeks. Microparticles with a single entrapped antigen (DT) induced better antibody responses than microparticles with two antigens entrapped simultaneously (DT + TT). Microparticles prepared from a single polymer were less effective for long term antibody induction than a combination of microparticles prepared from three different polymers. A combination vaccine consisting of antigen absorbed to alum and also entrapped in microparticles gave the best response. In an inhibition assay designed to determine the relative binding of antisera to the antigen, the sera from the microparticle and the alum immunized animals showed comparable binding. An intradermal challenge study was performed in rabbits, which showed similar levels for the alum and the microparticle immunized animals at 4, 12 and 32 weeks after immunization.

Pulse colliding in a self-mode-locked ring-cavity ti:sapphire laser

A new self-mode-locked ring-cavity Ti:sapphire laser is described that is self-mode locked in both unidirectional and bidirectional operations. We found that clockwise and counterclockwise pulses collide with each other at the Ti:sapphire rod when the laser is mode locked in a bidirectional operation. Spectrum narrowing and pulse broadening were found in bidirectional rather than unidirectional mode-locked operation. This is explained by the performance of a transient grating in the gain medium that restricts oscillation to a narrow spectral range.

Variation in ultrasonic backscattering from skeletal muscle during passive stretching

The purpose of this study was to further validate the scattering mechanism of ultrasound in the skeletal muscle tissue. It was hypothesized that the endomysial collagen fibers are a major determinant of ultrasonic scattering in the skeletal muscle. Previous studies have found that the ultrasonic backscattering from avian skeletal muscle changed as it was passively stretched from 0 to 40%. In this study, ultrasonic backscattering was measured from chicken breast muscles as they were stretched passively in increments of 10% of original length up to 60%. The integrated backscatter was found to reach a peak as the specimen was stretched to 40% and leveled off as it was further stretched from 40 to 60%. This finding was supported by results from scanning electron microscopy (SEM) of the specimens. SEM images showed that the orientation of the endomysial collagen fibers surrounding muscle fibers became approximately parallel to the axis of the muscle fiber when the muscle was stretched up to 40% of its original length, yielding maximal ultrasonic backscatter and as the muscle was further stretched, no apparent alteration of fiber orientation could be observed.

Use of caffeine as a probe for rapid determination of cytochrome P-450 CYP1A2 activity in humans

AIM

To develop a rapid HPLC method for the determination of cytochrome P-450 CYP1A2 activity.

METHODS

A 300-microL plasma was prepared by extraction with 5-mL chloroform/isopropanol (9:1), and beta-hydroxyletheophylline was added as internal standard (IS). Samples were separated on an ODS column by a gradient elution system, of which mobile phase consisted of 0.05% acetic acid, acetonitrile, and methanol. The compounds of interest were monitored at 282 nm by UV detector.

RESULTS

No potential interfering peaks were found. Paraxanthine (17X), IS and caffeine (137X) were rapidly eluted with baseline resolution, and their retention time was less than 13 min. The detection limits of both 17X and 137X were 0.1 mumol.L-1. Linear relations ranged over 1-100 mumol.L-1 and 1-200 mumol.L-1 with correlation coefficient of 0.9999 and 0.9987, respectively, for 17X and 137X. The coefficients of variation were within 6% for 17X, and 10% for 137X. The average recoveries for both compounds were ranged from 96% to 108%.

CONCLUSION

This method is sensitive and rapid, and can be used for population studies of CYP1A2.

Endoscopic resection of gastrointestinal submucosal tumors

BACKGROUND/AIMS

The occurrence of submucosal tumors in the gastrointestinal tract is not infrequent. According to endoscopic pictures, submucosal tumors can usually be diagnosed without difficulty. However, even with the aid of endoscopic ultrasound, a definite diagnosis is not possible without histological results. Before endoscopy became available, the treatment strategy for gastrointestinal submucosal tumors was either surgery or observation. Due to advances in scientific technology, endoscopic treatment of gastrointestinal submucosal tumors has become increasingly popular. In reviewing the literature, we found that only case reports or small series reports detailing specific tumors in specific locations existed previously.

METHODOLOGY

Endoscopic resection for 12 gastrointestinal submucosal tumors in 11 patients has been successfully performed in our hospital during the past three years.

RESULTS

The group included 5 men and 6 women, ranging in age from 28 to 78 years. The locations of the tumors consisted of 1 in the esophagus, 2 in the stomach, 1 in the jejunum, 5 in the colon and 3 in the rectum. Histological results showed 3 lipomas, 3 carcinoids, 2 leiomyomas, 1 ganglioneuromatous polyp, 1 hemangioma, 1 inflammatory fibroid polyp and 1 myomatous hyperplasia. Bleeding complications occurred in only 2 cases. One stopped spontaneously and the other stopped after epinephrine and sclerosant injection. Only 1 case required a two-step resection in order to avoid perforation. No tumor recurrence was noted during the follow-up period, which ranged from 2 months to 3 years.

CONCLUSIONS

In suitable cases, endoscopic resection of gastrointestinal submucosal tumors can be a safe and valuable method for treating symptomatic tumors and obtaining histological diagnosis of the submucosal tumors.

Colonofiberscopic diagnosis of intestinal tuberculosis

The purpose of this study was to assess the predictive value of colonofiberscopy in the diagnosis of intestinal tuberculosis. The records of more than 14,000 colonofiberscopic examinations performed at the National Taiwan University Hospital from 1971 to 1995 were studied retrospectively. Colonofiberscopic diagnosis of intestinal tuberculosis required at least one of the following: circumferential ulcers, a single transverse axis ulcer with uneven base and elevated or nodular margin surrounded by nodular and hyperemic mucosa, or pseudopolyps. Sixty cases were diagnosed as intestinal tuberculosis based on these criteria, 29 of which were confirmed by histologic or bacteriologic findings or on the basis of clinical response to antituberculosis therapy. The positive predictive value of colonofiberscopy for intestinal tuberculosis was thus 43.3% (95% confidence interval 31-57%). Secondary intestinal tuberculosis with pulmonary tuberculosis accounted for 84% of cases. The most commonly involved area of the gastrointestinal tract was the ileocecal region, followed by the ascending colon and ileum. Based on our findings, colonofiberscopic examination with histopathologic and bacteriologic study of biopsy specimens is a powerful tool for the diagnosis of intestinal tuberculosis.

Requirement of NF-kappaB activation to suppress p53-independent apoptosis induced by oncogenic Ras

The ras proto-oncogene is frequently mutated in human tumors and functions to chronically stimulate signal transduction cascades resulting in the synthesis or activation of specific transcription factors, including Ets, c-Myc, c-Jun, and nuclear factor kappa B (NF-kappaB). These Ras-responsive transcription factors are required for transformation, but the mechanisms by which these proteins facilitate oncogenesis have not been fully established. Oncogenic Ras was shown to initiate a p53-independent apoptotic response that was suppressed through the activation of NF-kappaB. These results provide an explanation for the requirement of NF-kappaB for Ras-mediated oncogenesis and provide evidence that Ras-transformed cells are susceptible to apoptosis even if they do not express the p53 tumor-suppressor gene product.

[An observation on the possible existance of some information transmission between sensory nerve endings of rat]

Dorsal cutaneous branches of the spinal nerves of T5-L1 segments on one side in anaesthesised rats were exposed and cut centrally. One peripheral end of the cut nerves was selected for antidromical stimulation, while an adjacent one for recording, both by Ag-AgCl electrodes. When a train of 50 Hz, 0.2 ms width square waves of 2 s was delivered to the nerve preparation for stimulation, the discharge of the adjacent nerve showed a remarkable increase and then subsided to the original level for about 25 s. Such experiments (n = 414) showed that the induced discharge frequency reached its maximum 2 s after the stimulation and maintained for another 2 s before subsiding to original level in about a period of 25 s. Using the discharge frequency at a certain time segment as an index, the degree of induced discharges of the recorded nerves were linearly related to their spontaneous discharges before stimulation and the sequences of stimulation to some extent. Single square stimulation was unable to induce one-to-one correspondent discharge in the recording nerve. Control experiments were done to rule out the induced discharges being due to the spreading of stimulating current. To summarize the results of all the above experiments, it appeared that some information transmission between sensory nerve endings may be present through some chemical events.

Comparative intraosseal growth of human prostate cancer cell lines LNCaP and PC-3 in the nude mouse

BACKGROUND

More than 75% of patients with advanced prostate carcinoma have skeletal involvement, which is the principal metastatic site and the major complication of this disease. The goal of this work was to compare the osseous metastasis of androgen-sensitive and insensitive prostate cancers in the nude mouse.

MATERIALS AND METHODS

Androgen-sensitive LNCaP or -insensitive PC-3 human prostate carcinoma cells were injected directly into the femur medullas of male nude Beige mice, the animals were then sacrificed at successive time intervals to study the gross and microscopic characteristics of the established tumors.

RESULTS

LNCaP and PC-3 both colonized in the bone marrow within a week, then gradually expanded to the entire bone medulla followed by osseous infiltration to produce obvious symptoms in the affected extremities. Based on the morphology, both osteoblastic and osteolytic changes occurred during the course of tumor progression. In addition, PC-3 tumors eventually broke through the bone cortex, invaded the surrounding tissues, and metastasized to the regional lymph nodes. In contrast, LNCaP remained localized within the bone, and appeared to eventually regress and die after displacing the normal bone marrow cells. Immunohistochemically, LNCaP tumors were consistently positive for prostate-specific antigen in bone metastasis, while PC-3 tumors were negative. Tumor cell nuclei of both PC-3 and LNCaP hybridized to a human repeated sequence DNA probe indicating that the proliferating malignant cells were of human origin.

CONCLUSIONS

These cancer cell lines produced a high incidence of growth in the bone that differed in histogenesis. The relative malignancy of these cell lines was demonstrated in this model.

Colorectal adenoma in patients with a history of breast cancer: a prospective study in Taiwan

The increased incidence of colorectal cancer in women with a history of breast cancer is well established. However, the relationship between the prevalence of adenomatous polyps and breast cancer is still controversial. We conducted a prospective study of the incidence of colorectal polyps in patients with a history of breast cancer in Taiwan. Eighty-nine patients (86 women and 3 men) received colonoscopy to test for precancerous lesions. Mean age was 49.4 +/- 10.4 years. Twelve polyps (9 adenomatous, 2 hyperplastic, 1 inflammatory) (13.5%) and one cancer (1.1%) were found. The mean age of patients with and without colorectal neoplasia was 56.3 +/- 9.4 and 48.2 +/- 10.2 years respectively, (p < 0.005); 10 out of 13 patients (77%) with colorectal neoplasia were over 50 (p < 0.1). Compared with a study of Chinese people in Hong Kong, our population had a lower incidence of colorectal adenomatous polyps, but breast cancer patients have a greater risk of developing colorectal cancer than the general population in Taiwan.

Diagnostic role of endoscopy, stool culture, and toxin A in Clostridium difficile-associated disease

This retrospective study was designed to assess the roles of stool culture for Clostridium difficile, detection of the presence of toxin A, and endoscopic examination in the diagnosis of Clostridium difficile-associated disease (CDAD). From January 1994 through September 1996, there were 213 patients with stool cultures positive for C. difficile in National Taiwan University Hospital. Of these, 126 had CDAD. There were 87 asymptomatic carriers of C. difficile in our study, 12 of whom were positive for toxin A. In addition, seven patients with pseudomembranous colitis (PMC), who were either culture-negative or not tested, were included in the study. The positive predictive values of stool cultures for CDAD and PMC were 59% and 32%, respectively. The positive predictive values of toxin A for CDAD and PMC were 41% and 43%, respectively. Seventy-eight patients (59%) improved with supportive treatment after discontinuing antibiotics. We concluded that stool culture for C. difficile and discontinuation of antibiotics should be the standard approach for patients with suspected CDAD. Endoscopic studies can eliminate some other possible causes of diarrhea such as inflammatory bowel disease, allow biopsies of suspicious lesions, and reveal the severity of CDAD. Toxin assay results need to be interpreted together with the clinical data.

Biodegradable microparticles with an entrapped branched octameric peptide as a controlled-release HIV-1 vaccine

Polyactide-co-glycolide microparticles, with an entrapped branched octameric peptide from human immunodeficiency virus (HIV-1), were prepared by a solvent evaporation method. The microparticles were characterized for size distribution, antigen loading level, and integrity. Mice in one group were each immunized with a single dose of a controlled-release microparticle formulation containing 300 micrograms of peptide and the serum IgG responses to the antigen were compared with those of mice from a second group that were immunized at 0, 4, and 26 weeks with 100-microgram doses of the same peptide immunogen adsorbed to alum. The controlled-release microparticles induced an antibody response comparable to that from the alum-immunized group. The subcutaneous and the intramuscular routes of administration were compared in additional groups of mice for the microparticles, and both routes induced similar responses. A suspending vehicle for the microparticles was also evaluated and did not affect the immunogenicity of the controlled-release formulation containing both small and large microparticles, although the immunogenicity of smaller microparticles immunized alone was affected.

CTL induction using synthetic peptides delivered in emulsions--critical role of the formulation procedure

Emulsions have been used with variable degrees of success to deliver antigen to stimulate immune responses. We have investigated three different ways of incorporating peptide antigen into soybean emulsions to induce CTL responses in mice. Two of these emulsions (oil-in-water, o/w, and water-in-oil-in-water, w/o/w) had peptide incorporated at the formulation stage, while the third had peptide added to a pre-formed o/w emulsion. High levels of CTL activity were induced when peptide was dispersed into the o/w or w/o/w emulsions, in contrast to addition of peptide to the pre-formed o/w emulsion, which did not stimulate a CTL response. Induction of CTL activity was independent of emulsion globule size but was correlated with a negative zeta potential and dispersion of peptide in the oil phase. The ability of peptide in soybean oil emulsion to induce CTL is critically dependent on dispersion of peptide at the time of emulsion formation.

Embryonic stem cell lines from MRL mice allow genetic modification in a murine model of autoimmune disease

The MRL/MpJ-Fas(lpr) (MRL-lpr/lpr) mouse spontaneously develops a generalized autoimmune disease with features similar to those of systemic lupus erythematosus. This mouse strain provides a valuable system for identifying and characterizing the multiple genetic factors that influence the pathogenesis of autoimmune diseases. One of the most powerful means of examining the role of a specific gene product in vivo is by inactivating the gene in mouse embryonic stem (ES) cells by homologous recombination and using these cells to derive mouse lines carrying the inactivated gene. The successful application of this approach, however, requires an ES cell line that will remain stable in culture during the processes of genetic manipulation and selection. To date, ES cell lines that meet this criterion have been derived from only a few mouse strains. Here we describe the production and characterization of stable ES cell lines from the MRL mouse strain. Approximately 7% of the blastocysts derived from the MRL/MpJ+ (MRL-+/+) strain gave rise to ES cell lines, and both of the male MRL-+/+ ES cell lines tested were shown to be germline competent. We show that the MRL-+/+ ES cell lines undergo gene targeting by homologous recombination at high frequency by inactivating the gene encoding the EP2 prostaglandin receptor. These Ep2-targeted MRL ES cell lines were used to generate MRL mouse lines heterozygous for the disrupted Ep2 gene, thus demonstrating the feasibility of using a genetic approach to dissect the pathobiology of the autoimmune disease in the MRL mouse.

Embryonic stem cell lines from MRL mice allow genetic modification in a murine model of autoimmune disease

The MRL/MpJ-Fas(lpr) (MRL-lpr/lpr) mouse spontaneously develops a generalized autoimmune disease with features similar to those of systemic lupus erythematosus. This mouse strain provides a valuable system for identifying and characterizing the multiple genetic factors that influence the pathogenesis of autoimmune diseases. One of the most powerful means of examining the role of a specific gene product in vivo is by inactivating the gene in mouse embryonic stem (ES) cells by homologous recombination and using these cells to derive mouse lines carrying the inactivated gene. The successful application of this approach, however, requires an ES cell line that will remain stable in culture during the processes of genetic manipulation and selection. To date, ES cell lines that meet this criterion have been derived from only a few mouse strains. Here we describe the production and characterization of stable ES cell lines from the MRL mouse strain. Approximately 7% of the blastocysts derived from the MRL/MpJ+ (MRL-+/+) strain gave rise to ES cell lines, and both of the male MRL-+/+ ES cell lines tested were shown to be germline competent. We show that the MRL-+/+ ES cell lines undergo gene targeting by homologous recombination at high frequency by inactivating the gene encoding the EP2 prostaglandin receptor. These Ep2-targeted MRL ES cell lines were used to generate MRL mouse lines heterozygous for the disrupted Ep2 gene, thus demonstrating the feasibility of using a genetic approach to dissect the pathobiology of the autoimmune disease in the MRL mouse.