Smoothelin and caldesmon are reliable markers for distinguishing muscularis propria from desmoplasia: a critical distinction for accurate staging colorectal adenocarcinoma

An accurate distinction between deep muscularis propria invasion versus subserosal invasion by colonic adenocarcinoma is essential for the accurate staging of cancer and subsequent optimal patient management. However, problems may arise in pathologic staging when extensive desmoplasia blurs the junction between deep muscularis propria and subserosal fibroadipose tissue. To address this issue, forty-three (43) cases of colonic adenocarcinoma resections from 2007-2009 at The Methodist Hospital in Houston, TX were reviewed. These cases were selected to address possible challenges in differentiating deep muscularis propria invasion from superficial subserosal invasion based on H&E staining alone. Immunohistochemical staining using smooth muscle actin (SMA), smoothelin, and caldesmon were performed on 51 cases: 8 cases of pT1 tumors (used mainly as control); 12 pT2 tumors; and 31 pT3 tumors. All 51 (100%) had diffuse, strong (3+) immunoreactivity for caldesmon and smoothelin in the muscularis propria with a granular cytoplasmic staining pattern. However, the desmoplastic areas of these tumors, composed of spindled fibroblasts and myofibroblasts, showed negative immunostaining for caldesmon and smoothelin (0/35). SMA strongly stained the muscularis propria and weakly (1+) or moderately (2+) stained the spindled fibroblasts in the desmoplastic areas (the latter presumably because of myofibroblastic differentiation). Compared to SMA, caldesmon and smoothelin are more specific stains that allow better delineation of the muscularis propria from the desmoplastic stromal reaction which provides a critical aide for proper staging of colonic adenocarcinoma and subsequent patient care.     

Immunohistochemical localization of neurotransmitters utilized by neurons in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) that project to the oculomotor and trochlear nuclei in the cat

The rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) contains excitatory and inhibitory burst neurons that are related to the control of vertical and torsional eye movements. In the present study, light microscopic examination of the immunohistochemical localization of amino acid neurotransmitters demonstrated that the riMLF in the cat contains overlapping populations of neurons that are immunoreactive to the putative inhibitory neurotransmitter γ-aminobutyric acid (GABA) and the excitatory neurotransmitters glutamate and aspartate. By using a double-labelling paradigm, GABA-, glutamate-, and aspartate-immunoreactive neurons in the riMLF were retrogradely labelled by transport of horseradish peroxidase (HRP) from the oculomotor and trochlear nuclei. Electron microscopy showed that the oculomotor and trochlear nuclei contain synaptic endings that are immunoreactive to GABA, glutamate, or aspartate. Each neurotransmitter-specific population of synaptic endings has distinctive ultrastructural and synaptic features. Synaptic endings in the oculomotor and trochlear nuclei that are anterogradely labelled by transport of biocytin from the riMLF are immunoreactive to GABA, glutamate, or aspartate. Taken together, the findings from these complimentary retrograde and anterograde double-labelling studies provide rather conclusive evidence that GABA is the inhibitory neurotransmitter, and glutamate and aspartate are the excitatory neurotransmitters, utilized by premotor neurons in the riMLF that are related to the control of vertical saccadic eye movements. © 1996 Wiley-Liss, Inc.     

5-Azacytidine-induced 6-thioguanine resistance at the gpt locus in AS52 cells: Cellular response

Treatment of AS52 cells with 5-azacytidine resulted in an induction of 6-thioguanine-resistant (6TG′) colonies, which reached a maximum by an expression time of 9 days. Dose responses for both cytotoxicity and mutation induction were determined following treatment with 5-azacytidine. At 20 μM treatment, 5-azacytidine exposure resulted in about 50% survival. Mutant frequency reached a maximum at 10 μM. At concentrations between 10 and 20 μM, 5-azacytidine was a potent mutagen but did not exhibit a dose response. Although many compounds both induce cell death and affect the growth rate of cells, 5-azacytidine specifically induced cell death and did not affect the doubling time of the surviving treated cell population. © 1996 Wiley-Liss, Inc.     

An evaluation of the effects of susceptibility changes on the water chemical shift method of temperature measurement in human peripheral muscle

Divergencies between chemical shift measurements of temperature and directly measured values using optical sensors have been studied in vivo in human peripheral muscle with the assistance of a variety of experimental and theoretical techniques. These include the modeling of both thermal and susceptibility changes using two- and three-dimensional finite element methods, as well as the use of multi-wavelength near infrared observations. The conclusion of these studies is that a simple temperature calibration is not accessible, with results affected by the complex response of the tissue itself.