Optical coherence tomography of the esophagus and proximal stomach in health and disease

OBJECTIVE: Surveillance of Barrett's esophagus is problematic, as high-grade dysplasia cannot be recognized endoscopically. Endoscopic ultrasound lacks the resolution to detect high-grade dysplasia. Optical coherence tomography (OCT) employs infrared light reflectance to provide in vivo tissue images at resolution far superior to endoscopic ultrasound, nearly at the level of histology. We have developed a catheter-based system well suited for study of the GI tract. The purpose of this study was to test this catheter-based OCT system and characterize the OCT appearance of normal squamous mucosa, gastric cardia, Barrett's esophagus, and carcinoma. METHODS: The OCT catheter was passed through the operating channel of the endoscope and placed in contact with the esophageal mucosa. Image acquisition occurred in approximately 3 s. OCT images were correlated with biopsy and/or resection specimens. RESULTS: OCT was used to construct 477 images of the esophagus and stomach in 69 patients. There were unique, distinct OCT appearances of squamous mucosa, gastric cardia, Barrett's esophagus, and carcinoma. Further, these OCT images were accurately recognized by observers unaware of their site of origin. CONCLUSIONS: OCT provides a highly detailed view of the GI wall, with clear delineation of a multiple layered structure. It is able to distinguish squamous mucosa, gastric cardia, Barrett's esophagus, and cancer. This technique holds great potential as an adjunct to the surveillance of patients with Barrett's esophagus, ulcerative pancolitis, and other premalignant conditions.     

Positron emission tomography for preoperative staging of colorectal carcinoma

PURPOSE: Positron emission tomography (PET) is an imaging technique based onin vivo cellular metabolism. Increased glucose metabolism in neoplastic cells is detected by using fluorine-18 deoxyglucose. In an ongoing pilot study to determine the usefulness of this technique, PET is compared with computerized tomography (CT) for the preoperative staging of colorectal carcinoma. METHODS: Sixteen patients were evaluated with both PET and CT of the abdomen and pelvis. Results were compared with operative and histopathologic findings. Fifteen malignant lesions were found in 16 patients by histology. PET had a positive predictive value of 93 percent and a negative predictive value of 50 percent. By comparison CT had a positive predictive value of 100 percent and a negative predictive value of 27 percent. CONCLUSIONS: These preliminary results indicate that PET has increased sensitivity for staging colorectal carcinoma, whereas CT has higher specificity. The predictive value of a positive PET compares favorably with CT. Furthermore, the predictive accuracy for detection of colorectal carcinoma is 83 percent for PET and 56 percent for CT.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, San Francisco, California, June 7 to 12, 1992.Presented in part in the Nebraska Medical Journal, February 1993.     

In vivo measurement of dose distribution in patients' lymphocytes: helical tomotherapy versus step-and-shoot IMRT in prostate cancer

In radiotherapy, in vivo measurement of dose distribution within patients'' lymphocytes can be performed by detecting gamma-H2AX foci in lymphocyte nuclei. This method can help in determining the whole-body dose. Options for risk estimations for toxicities in normal tissue and for the incidence of secondary malignancy are still under debate. In this investigation, helical tomotherapy (TOMO) is compared with step-and-shoot IMRT (SSIMRT) of the prostate gland by measuring the dose distribution within patients'' lymphocytes. In this prospective study, blood was taken from 20 patients before and 10 min after their first irradiation fraction for each technique. The isolated leukocytes were fixed 2 h after radiation. DNA double-stranded breaks in lymphocyte nuclei were stained immunocytochemically using anti-gamma-H2AX antibodies. Gamma-H2AX foci distribution in lymphocytes was determined for each patient. Using a calibration line, dose distributions in patients'' lymphocytes were determined by studying the gamma-H2AX foci distribution, and these data were used to generate a cumulative dose–lymphocyte histogram (DLH). Measured in vivo (DLH), significantly fewer lymphocytes indicated low-dose exposure (<40% of the applied dose) during TOMO compared with SSIMRT. The dose exposure range, between 45 and 100%, was equal with both radiation techniques. The mean number of gamma-H2AX foci per lymphocyte was significantly lower in the TOMO group compared with the SSIMRT group. In radiotherapy of the prostate gland, TOMO generates a smaller fraction of patients'' lymphocytes with low-dose exposure relative to the whole body compared with SSIMRT. Differences in the constructional buildup of the different linear accelerator systems, e.g. the flattening filter, may be the cause thereof. The influence of these methods on the incidence of secondary malignancy should be investigated in further studies.     

Nucleoprotein‐specific nonneutralizing antibodies speed up LCMV elimination independently of complement and FcγR

CD8⁺ T cells have an essential role in controlling lymphocytic choriomeningitis virus (LCMV) infection in mice. Here, we examined the contribution of humoral immunity, including nonneutralizing antibodies (Abs), in this infection induced by low virus inoculation doses. Mice with impaired humoral immunity readily terminated infection with the slowly replicating LCMV strain Armstrong but showed delayed virus elimination after inoculation with the faster replicating LCMV strain WE and failed to clear the rapidly replicating LCMV strain Docile, which is in contrast to the results obtained with wild‐type mice. Thus, the requirement for adaptive humoral immunity to control the infection was dependent on the replication speed of the LCMV strains used. Ab transfers further showed that LCMV‐specific IgG Abs isolated from LCMV immune serum accelerated virus elimination. These Abs were mainly directed against the viral nucleoprotein (NP) and completely lacked virus neutralizing activity. Moreover, mAbs specific for the LCMV NP were also able to decrease viral titers after transfer into infected hosts. Intriguingly, neither C3 nor Fcγ receptors were required for the antiviral activity of the transferred Abs. In conclusion, our study suggests that rapidly generated nonneutralizing Abs specific for the viral NP speed up virus elimination and thereby may counteract T‐cell exhaustion.     

Characterisation of a monoclonal antibody detecting Atlantic salmon endothelial and red blood cells,and its association with the infectious salmon anaemia virus cell receptor

Endothelial cells (ECs) line the luminal surfaces of the cardiovascular system and play an important role in cardiovascular functions such as regulation of haemostasis and vasomotor tone. A number of fish and mammalian viruses target these cells in the course of their infection. Infectious salmon anaemia virus (ISAV) attacks ECs and red blood cells (RBCs) of farmed Atlantic salmon (Salmo salar L.), producing the severe disease of infectious salmon anaemia (ISA). The investigation of ISA has up to now been hampered by the lack of a functional marker for ECs in Atlantic salmon in situ. In this study, we report the characterisation and use of a novel monoclonal antibody (MAb) detecting Atlantic salmon ECs (e.g. vessel endothelium, endocardial cells and scavenger ECs) and RBCs. The antibody can be used with immunohistochemistry, IFAT and on Western blots. It appears that the epitope recognised by the antibody is associated with the ISAV cellular receptor. Besides being a tool to identify ECs in situ, it could be useful in further studies of the pathogenicity of ISA. Finally, the detection of an epitope shared by ECs and RBCs agrees with recent findings that these cells share a common origin, thus the MAb can potentially be used to study the ontogeny of these cells in Atlantic salmon.     

A study of conformational restraints on reactivity of human PR3-specific autoantibodies (ANCA) facilitated through protein folding manipulations of a new recombinant proteinase 3 protein

Proteinase 3 (PR3)-specific antineutrophil cytoplasmic autoantibodies (PR3-ANCA) recognize conformational epitopes on PR3. This study evaluates PR3-ANCA target epitopes utilizing a novel recombinant PR3 (rPR3) produced to accommodate manipulations of the N-terminal domain. The rPR3 molecule contains an N-terminus six histidine tag, which can be removed by enterokinase (EK) cleavage of an adjacent EK cleavage site. Once cleaved the remaining amino acids correspond to the mature N-terminus of PR3. This rPR3 can be manipulated to produce three variant forms: tagged rPR3^+his, EK-cleaved (his-tag removed) rPR3^{? his}, and EK-cleaved, denatured/refolded rPR3^{? his/dr} (the proteolytically active form). Patients with clinically positive PR3-ANCA titers (n = 40) were confirmed for reactivity against purchased native PR3 in our system. Controls included 29 healthy volunteers and 34 MPO-ANCA patients. All PR3-ANCA sera samples tested were reactive with one or more forms of the recombinant protein (greater than mean ELISA OD 405 + 2 SDs of controls). Of significance, three sera were reactive with non-active forms only and three others were more reactive with rPR3^{? his/dr} than with native PR3. The results of our evaluation of PR3-ANCA sera for reactivity against the three forms of our rPR3 protein uniquely exemplify the diverse array of epitopes within the PR3-ANCA population. This new recombinant form of PR3 should provide a suitable approach to mapping ANCA epitopes using site-directed mutagenesis.     

Regulation of Migration of Human Colonic Myofibroblasts

Background and Aim: The migration of mesenchymal cells to areas of mucosal or submucosal tissue damage is an essential factor for wound healing in the intestine. Thus far, neither migration inducing factors nor signal transduction cascades involved in the migration of colonic myofibroblasts (CMF) have been studied in detail. Methods: Primary CMF were isolated from the mucosa of surgical specimens or endoscopic biopsies. Migration assays of CMF were performed in the modified 48-well Boyden chamber. Secreted growth factors were quantified by ELISA. Results: CMF secrete autocrine or paracrine migration stimulating factors. Culture supernatant of CMF collected after 24, 48, and 72 h (=conditioned media) stimulated the migration of CMF ( 48.9 &#45 4.5; 60.3 &#45 5.3 and 67.8 &#45 6.4 cells/hpf, respectively). Heating of conditioned media to 95°C or addition of cycloheximide during the conditioning period abolished migration. Addition of PDGF-AB (2.5-50 ng/ml) or IGF-I (10-300 ng/ml) to CMF conditioned media further increased the migration of CMF to a maximum of 177 and 160%, respectively, when compared to the migration induced by conditioned medium alone. Addition of EGF (2.5-50 ng/ml) or TGF- &#103 1 (1-50 pg/ml) caused an increased CMF migration up to 139 and 128%, respectively. MCP-1 (5-50 ng/ml) and bFGF (10-200 ng/ml) had no effect on CMF migration. Conclusion: The growth factors PDGF-AB, IGF-I, EGF and TGF- &#103 1 stimulate the migration of CMF. However, factors secreted by CMF are essential for their ability to migrate in response to these growth factors. The identification of physiologically relevant migration inducing factors may help to elucidate the network of interactions and the complex mechanisms involved in intestinal wound healing or fibrosis.     

Effect of three different Pilates sessions on energy expenditure and aerobic metabolism in healthy females

Sport Sciences for Health - The Pilates method has become a popular exercise modality. However, there is little information on the energy expenditure (EE) and aerobic metabolism involved in a...