Obvious Difference In Number Research Articles

Polydimethylsiloxane as a more biocompatible alternative to glass in optogenetics

Optogenetics is highly useful to stimulate or inhibit defined neuronal populations and is often used together with electrophysiological recordings. Due to poor penetration of light in tissue, there is a need for biocompatible wave guides. Glass wave guides are relatively stiff and known to cause glia reaction that likely influence the activity in the remaining neurons. We developed highly flexible micro wave guides for optogenetics that can be used in combination with long-lasting electrophysiological recordings. We designed and evaluated polydimethylsiloxane (PDMS) mono-fibers, which use the tissue as cladding, with a diameter of 71 ± 10 µm and 126 ± 5 µm. We showed that micro PDMS fibers transmitted 9–33 mW/mm2 light energy enough to activate channelrhodopsin. This was confirmed in acute extracellular recordings in vivo in which optogenetic stimulation through the PDMS fibers generated action potentials in rat hippocampus with a short onset latency. PDMS fibers had significantly less microglia and astrocytic activation in the zone nearest to the implant as compared to glass. There was no obvious difference in number of adjacent neurons between size matched wave guides. Micro PDMS wave guide demonstrates in vivo functionality and improved biocompatibility as compared to glass. This enables the delivery of light with less tissue damage.

In-situ localisation of immunocompetent cells in Fasciola hepatica infestation in rats and mice.

Fasciola hepatica (Liver fluke) is primarily a parasite of cattle and sheep, although other animals may also become infested [I] . Cattle and rats have been found to develop partial resistance to re-infestation with Fasciola hepatica, sheep and mice however, develop no effective immune response and are susceptible to reinfestation [2]. Thus, rats and mice provide useful models for the disease in cattle and sheep respectively. The parasite burrows through the intestinal wall migrating through the liver on its way to the larger bilary passages, its site of chronic infestation and egg production. Therefore, a localisation of immunocompetent cells within the intestine of rats and mice following infestation with Fasciola hepatica was investigated. A prospective study was carried out in which groups of 5 mice and rats were infested with metacercariae from Fasciola hepatica, along with the same number of uninfested control siblings and sacrificed 21 days later. A further group of 5 rats were infested with metacercariae and on day 21 were rechallenged. These animals were sacrificed 72 hours post rechallenge. Intestinal cryostat sections were prepared and stained with monoclonal antibodies against CD8, CD4, CD3, and MHC class 11. In addition, histological mast cell staining of all groups was carried out using Astra blue. In the normal mouse, the majority of CD8' cells formed a characteristic pattern of what have been referred to as 'cords' or 'rows' of cells underlying the epithelium of the villi with occasional intraepithelial lymphocytes observed [3]. CD4' cells were predominately confined to the lamina propria. CD3' cells formed a pattern representative of combined CD4 and CD8 cell panerns. Mast cells were detected in the sub-mucosa and lamina propria in very low numbers. No obvious difference in number, intensity or location of any of these cell types was seen between infested and control mice. The particular monoclonal antibody used to detect mouse MHC class I1 failed to give reproducible immunohistochemical staining. In the normal rat, CD8' cells, although in the same location, were less numerous and did not form 'cords' as frequently as in mouse tissue. CD4' cells were predominately confined to the lamina propria, and numerous MHC class 11' cells were also located to this region. Mast cells were found in the submucosa and lamina propria in greater numbers than in mouse tissue. Primary infested rats showed no difference in CD8' cell numbers or distribution. However, as a group, MHC class I1 and CD4 cell staining was more intense in these animals than in controls, although no obvious difference in cell distribution patterns was observed. Mast cell numbers were considerably increased. In re-infested rats, the intensity of MHC class I1 and CD4 cell staining was consistently weaker than even the control groups, but mast cell numbers remained elevated. Once again, no difference was seen in the CD8' cell population. Lack of an effective immune response leading to susceptibility is reflected by the apparent similarity of cell numbers and staining intensity between controls and infested mice. The increased staining intensity of MHC class 11' and CD4' cells and increased mast cell numbers observed in primary infested rats may be indicative of an effective immune response in these animals.

The serotoninergic bulbospinal system and brainstem-spinal cord content of serotonin-, TRH-, and substance P-like immunoreactivity in the aged rat with special reference to the spinal cord motor nucleus.

The 5-hydroxytryptamine (5HT) containing bulbospinal pathway was studied with immunohistochemical (IF) and chemical techniques in 2-3 and 30 months old male Sprague-Dawley rats. The coexisting neuropeptides substance P (SP), thyrotropin-releasing hormone (TRH) and galanin were also analysed. Furthermore, the expression of mRNA encoding aromatic L-amino acid decarboxylase (AADC), prepro-TRH, and preprotachykinin (prepro-SP) was analysed with in situ hybridization (ISH) in the midline raphé nuclei inthe lower brainstem. The results showed a decreased number of axonal 5HT fibers with a normal morphology in the ventral horn of the aged rat lumbosacral spinal cord, and several 5HT immunoreactive (IR) fibers with an aberrant morphology, suggestive of axonal degeneration, were intermingled. This was evident in both the dorsal and ventral horn of the spinal cord. The 5HT-IR fibers with an aberrant morphology usually also contained TRH-and/or SP- and/or galanin-like immunoreactivity (LI) in the ventral horn. These signs of degeneration were clearly less evident in the thoracic and cervical spinal cord segments. Moreover, these changes varied between aged litter-mates. This was in agreement with behavioural signs of motor disturbances, present in about 40% of the aged rats and which in all cases were confined to the hindlimbs. Chemical analyses disclosed significantly lower levels of TRH-LI and, in particular, SP-LI in both the ventral and dorsal quandrants of the spinal cord in the aged rat compared to young adults. The differences were largest in the lumbar regions of the spinal cord. Corresponding analysis of 5HT and 5-hydroxyindoleacetic acid (5HIAA) in the same tissue specimens revealed largely unaltered levels of 5HT and a slight increase in 5HIAA, indicating the possibility of an increased 5HT turnover in the aged rat spinal cord. Neurons in nucleus raphé obscurus and nucleus raphé pallidus were immunoreactive to 5HT, and after pretreatment with colchicine to TRH-, SP-, and galanin-LI as well. There was no obvious difference in number of labeled cells, or labeling intensity, between colchicine-treated young adult and aged rats, although, in the corresponding region of medulla oblongata, chemical analysis disclosed significantly lower levels of 5HT, TRH, and, in particular, SP in untreated aged rats. In contrast, in situ hybridization analysis revealed increased mRNA levels encoding prepro-TRH and prepro-SP in old rats, while mRNA content encoding AADC mRNA was similar in young adult and aged rats.(ABSTRACT TRUNCATED AT 400 WORDS)

ヒト皮膚へん平上皮癌，ボーエン病，基底細胞癌におけるＳ‐１００蛋白陽性樹状細胞の免疫組織学的検討

We have studied immunohistochemically 125 cases of skin malignant tumors, including 53 cases of squamous cell carcinoma (SCC), 21 cases of Bowen's disease (BOD) and 51 cases of basal cell carcinoma (BCC), to investigate the difference of in number and distribution positive cells with antibodies to S-100 protein, pan-T cell, pan-B cell and HLA-DR alpha chain. The numbers of S-100 protein-positive dendritic cells (S-100+DC), and of lymphocytes in SCC increased statistically in comparison with those observed in BCC. In BOD, their numbers were intermediate. According to Broders' classification of SCC, S-100+DC infiltration roughly increased in number, along with keratinization. Ultramorphologically, it was demonstrated that these S-100+DC contained indented nuclei, extending their processes among cancer cells. Double immunostaining for the presence of both S-100 protein and HLA-DR alpha chain demonstrated a few but distinctive double-positive dendritic cells in cancer cell nests of SCC. Based on these findings, we concluded that the obvious difference in number and distribution of both S-100+DC and lymphocytes was present between SCC and BCC.