He—Ne激光经皮脊髓照射对大鼠前角神经元内若干种酶活性的影响

大白鼠一侧坐骨神经钳夹损伤后,采用 He-Ne 激光脊髓相应节段经皮照射。14天后对脊髓 L(4～6)节段切片进行 G6PDH、SDH、5'-NT、AchE、ACP 的酶组织化学染色,观察上述酶活性的变化。发现:激光照射组 G6PDH、AchE 活性较损伤对照组增高,损伤组5'-NT 较正常组增高,SDH 无明显变化。这些酶活性的改变可能是低功率激光促神经生长的原因之一。     

Side‐effects of thiamethoxam on the brain andmidgut of the africanized honeybee Apis mellifera (Hymenopptera: Apidae)

The development of agricultural activities coincides with the increased use of pesticides to control pests, which can also be harmful to nontarget insects such as bees. Thus, the goal of this work was assess the toxic effects of thiamethoxam on newly emerged worker bees of Apis mellifera (africanized honeybee—AHB). Initially, we determined that the lethal concentration 50 (LC₅₀) of thiamethoxam was 4.28 ng a.i./μL of diet. To determine the lethal time 50 (LT₅₀), a survival assay was conducted using diets containing sublethal doses of thiamethoxam equal to 1/10 and 1/100 of the LC_50. The group of bees exposed to 1/10 of the LC₅₀ had a 41.2% reduction of lifespan. When AHB samples were analyzed by morphological technique we found the presence of condensed cells in the mushroom bodies and optical lobes in exposed honeybees. Through Xylidine Ponceau technique, we found cells which stained more intensely in groups exposed to thiamethoxam. The digestive and regenerative cells of the midgut from exposed bees also showed morphological and histochemical alterations, like cytoplasm vacuolization, increased apocrine secretion and increased cell elimination. Thus, intoxication with a sublethal doses of thiamethoxam can cause impairment in the brain and midgut of AHB and contribute to the honeybee lifespan reduction. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1122–1133, 2014.     

Entorhinal cortex modules of the human brain

Much is known about modular organization in the cerebral cortex, but this knowledge is skewed markedly toward primary sensory areas, and in fact, it has been difficult to demonstrate elsewhere. In this report, we test the hypothesis that a unique form of modules exists in the entorhinal area of the human cortex (Brodmann's area 28). We examined this issue using classic cyto- and myeloarchitectonic stains, immunolabeling for various neurochemicals, and histochemistry for certain enzymes. The findings reveal that the entorhinal cortex in the human is formed by a mosaic of cellular aggregates whose most conspicuous elements are the cell islands of layer II and myelinated fibers around the cell islands, the disposition of glutamic acid decarboxylase-positive neurons and processes, cytochrome oxidase staining, and the pattern of cholinergic afferent fibers. The neuropathology of Alzheimer's disease cases highlights the modules, but inversely so, by destroying their features. The findings are of interest because 1) anatomically defined modules are shown to be present in areas other than the sensory and motor cortices, 2) the modules are morphological entities likely to reflect functions of the entorhinal cortex, and 3) the destruction of entorhinal cortex modules may account disproportionately for the severity of memory impairments in Alzheimer's disease. © 1996 Wiley-Liss, Inc.     

Chondroitin sulfate proteoglycans in the developing central nervous system. I. Cellular sites of synthesis of neurocan and phosphacan

We have used in situ hybridization histochemistry to examine the cellular sites of synthesis of two major nervous tissue proteoglycans, neurocan and phosphacan, in embryonic and postnatal rat brain and spinal cord. Both proteoglycans were detected only in nervous tissue. Neurocan mRNA was evident in neurons, including cerebellar granule cells and Purkinje cells, and in neurons of the hippocampal formation and cerebellar nuclei. In contrast, phosphacan message was detected only in astroglia, such as the Golgi epithelial cells of the cerebellum. At embryonic day 13–16, phosphacan mRNA is largely confined to areas of active cell proliferation (e.g., the ventricular zone of the ganglionic eminence and septal area of the brain and the ependymal layer surrounding the central canal of the spinal cord) as well as being present in the roof plate. The distribution of neurocan message is more widespread, extending to the cortex, hippocampal formation, caudate putamen, and basal telencephalic neuroepithelium, and neurocan mRNA is present in both the ependymal and mantle layers of the spinal cord but not in the roof plate. The presence of neurocan mRNA in areas where the proteoglycan is not expressed suggests that the short open reading frame in the 5′-leader of neurocan may function as a cis-acting regulatory signal for the modulation of neurocan expression in the developing central nervous system. © 1996 Wiley-Liss, Inc.     

Topographical distribution of NADPH-diaphorase activity in the central nervous system of the frog,Rana perezi

The distribution of NADPH-diaphorase (ND) activity was histochemically investigated in the brain of the frog Rana perezi. This technique provides a highly selective labeling of neurons and tracts. In the telencephalon, labeled cells are present in the olfactory bulb, pallial regions, septal area, nucleus of the diagonal band, striatum, and amygdala. Positive neurons surround the preoptic and infundibular recesses of the third ventricle. The magnocellular and suprachiasmatic hypothalamic nuclei contain stained cells. Numerous neurons are present in the anterior, lateral anterior, central, and lateral posteroventral thalamic nuclei. Positive terminal fields are organized in the same thalamic areas but most conspicuously in the visual recipient plexus of Bellonci, corpus geniculatum of the thalamus, and the superficial ventral thalamic nucleus. Labeled fibers and cell groups are observed in the pretectal area, the mesencephalic optic tectum, and the torus semicircularis. The nuclei of the mesencephalic tegmentum contain abundant labeled cells and a conspicuous cell population is localized medial and caudal to the isthmic nucleus. Numerous cells in the rhombencephalon are distributed in the octaval area, raphe nucleus, reticular nuclei, sensory trigeminal nuclei, nucleus of the solitary tract, and, at the obex levels, the dorsal column nucleus. Positive fibers are abundant in the superior olivary nucleus, the descending trigeminal, and the solitary tracts. In the spinal cord, a large population of intensely labeled neurons is present in all fields of the gray matter throughout its rostrocaudal extent. Several sensory pathways were heavily stained including part of the olfactory, visual, auditory, and somatosensory pathways. The distribution of ND-positive cells did not correspond to any single known neurotransmitter or neuroactive molecule system. In particular, abundant codistribution of ND and catecholamines is found in the anuran brain. Double labeling techniques have revealed restricted colocalization in the same neurons and only in the posterior tubercle and locus coeruleus. If ND is in amphibians a selective marker for neurons containing nitric oxide synthase, as generally proposed, with this method the neurons that may synthesize nitric oxide would be identified. This study provides evidence that nitric oxide may be involved in novel tasks, primarily related to forebrain functions, that are already present in amphibians. © 1996 Wiley-Liss, Inc.     

Expression of a phosphorylated isoform of MAP1B is maintained in adult central nervous system areas that retain capacity for structural plasticity

Microtubule-associated protein IB (MAP1B) is the first MAP to be detected in the developing nervous system, and it becomes markedly down-regulated postnatally. Its expression, particularly that of its phosphorylated isoform, is associated with axonal growth. To determine whether adult central nervous system (CNS) areas that retain immunoreactivity for MAP1B are associated with morphological plasticity, we compared the distribution of a phosphorylated MAP1B isoform (MAP1B-P) to the distribution of total MAP1B protein and MAP1B-mRNA. Although they were present only at very low levels, both protein and message were found ubiquitously in almost all adult CNS neurons. The intensity of staining, however, varied markedly among different regions, with only a few nuclei retaining relatively high levels. MAP1B-P was restricted to axons, whereas total MAP1B was present in cell bodies and processes. Relatively to total MAP1B protein and its mRNA, MAP1B-P levels decreased more dramatically with maturation, and they were detectable in only a few specific areas that underwent structural modifications. These included primary afferents and motor neurons, olfactory tubercles, habenular and raphe projections to interpeduncular nuclei, septum, and the hypothalamus. The distribution pattern of MAP1B-P was compared to that of the embryonic N-CAM rich in polysialic acid (PSA-NCAM). We found that the PSA-NCAM immunostaining was largely overlapped with that of MAP1B-P in the adult CNS. These results suggest that, like PSA-NCAM, MAP1B may be one of the molecules expressed during brain development that also plays a role in structural remodeling in the adult. © 1996 Wiley-Liss, Inc.     

Comparative analysis of colorimetric staining in skin using open‐source software

Colorimetric staining techniques such as immunohistochemistry (IHC), immunofluorescence (IF) and histochemistry (HC) provide useful information regarding the localization and relative amount of a molecule/substance in skin. We have developed a novel, straightforward method to assess colorimetric staining by combining features from two open‐source software programs. As a proof of principle, we demonstrate the utility of this approach by analysing changes in skin melanin deposition during the radiation‐induced tanning response of Yucatan mini‐pigs. This method includes a visualization step to validate the accuracy of colour selection before quantitation to ensure accuracy. The data show that this method is robust and will provide a means to obtain accurate comparative analyses of staining in IHC/IF/HC samples.     

The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions

This study is an investigation of the relationship between muscle morphology and surface electromyographic (EMG) parameters [mean frequency of the power spectrum (MNF), signal amplitude (root mean square, RMS) and the signal amplitude ratio (SAR; i.e. the ratio between the RMS level during the passive part of the contraction cycle and the RMS level during the active part of the contraction cycle)] during 100 maximal dynamic knee extensions at 90° · s⁻¹. Each contraction cycle comprised of 1 s of active knee extension and 1 s of passive knee flexion. The surface EMG was recorded from the vastus lateralis muscle. Twenty clinically healthy subjects participated in the study, and muscle biopsy samples of the vastus lateralis were obtained from 19 of those subjects. The relationships between muscle morphology and EMG were investigated at three stages of the test: initially, during the fatigue phase (initial 40 contractions), and at the endurance level (the final 50 contractions). Major findings on correlations are that SAR and MNF tended to correlate positively with the proportion of type 1 fibres, and RMS correlated positively with the proportion of type 2 muscle fibres. The muscle fibre areas showed little correlation with the EMG variables under investigation. The results of the present study showed that the three EMG variables of a dynamic endurance test that were investigated (RMS, MNF and SAR) were clearly correlated with the proportions of the different fibre types, but only to a small extent with fibre areas. These findings contradict some of the theoretical models of the EMG, especially for parameters in the frequency domain. Accepted: 17 June 1999