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Robertson RT; Gallardo KA; Claytor KJ; Ha DH; Ku KH; Yu BP; Lauterborn JC; Wiley RG; Yu J; Gall CM; Leslie FM 《Cerebral cortex (New York, N.Y. : 1991)》1998,8(2):142-155
The role of basal forebrain-derived cholinergic afferents in the
development of neocortex was studied in postnatal rats. Newborn rat pups
received intraventricular injections of 192 IgG-saporin. Following survival
periods ranging from 2 days to 6 months, the brains were processed to
document the cholinergic lesion and to examine morphological consequences.
Immunocytochemistry for choline acetyltransferase (ChAT) and in situ
hybridization for ChAT mRNA demonstrate a loss of approximately 75% of the
cholinergic neurons in the medial septum and nucleus of the diagonal band
of Broca in the basal forebrain. In situ hybridization for glutamic acid
decarboxylase mRNA reveals no loss of basal forebrain GABAergic neurons.
Acetylcholinesterase histochemistry demonstrates a marked reduction of the
cholinergic axons in neocortex. Cholinergic axons are reduced throughout
the cortical layers; this reduction is more marked in medial than in
lateral cortical areas. The thickness of neocortex is reduced by
approximately 10%. Retrograde labeling of layer V cortico-collicular
pyramidal cells reveals a reduction in cell body size and also a reduction
in numbers of branches of apical dendrites. Spine densities on apical
dendrites are reduced by approximately 20-25% in 192 IgG- saporin-treated
cases; no change was detected in number of spines on basal dendrites. These
results indicate a developmental or maintenance role for cholinergic
afferents to cerebral cortical neurons.
相似文献
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Following lobectomy of the right upper lobe of the lung, a single fissure, the neofissure, separates the right middle and lower lobes. In 25 patients in whom chest radiographs and computed tomographic (CT) scans were obtained after right upper lobectomy, the neofissure was identifiable to some extent on the radiographs in seven (28%) and on CT scans in 24 (96%). Among those patients in whom the neofissure was seen in its entirety, in 12 of 20 (60%) it was oriented predominantly in the coronal plane, paralleling the course of the original major fissure but displaced anteriorly and superiorly. In seven of 20 patients (35%) the superior aspect was coronal, rotated clockwise toward the sagittal plane inferiorly. In one of 20 patients (5%) the neofissure was oriented predominantly in the sagittal plane. The right middle lobe lies anterior and medial to the neofissure; the right lower lobe lies posterior and lateral. 相似文献
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A polymer system was developed for use in permanent inflation of detachable balloons, to avoid long-term reliance on the integrity of balloon shells or valve mechanisms. This system is based on 2-hydroxy-ethyl methacrylate (HEMA) as the monomer, in combination with a cross-linking agent and a water-soluble curing system. The low-viscosity, hydrophilic mixture can be exchanged through a small-bore catheter into a detachable balloon and polymerizes in 40-60 minutes at body temperature. Partially polymerized HEMA can cause vascular occlusion; hence, careful timing of balloon detachment is required. The evolution of the radiographic appearance of HEMA-filled balloons is predictable. The balloons remain radiopaque on plain radiographs as long as the balloon shell and valve mechanisms are competent. After rupture of the shell or failure of the valve mechanism, the balloons become invisible on plain radiographs but remain hyperattenuating on computed tomography scans. 相似文献
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A screening program of 10,040 cigarette-smoking men over 45 years of age was undertaken in an attempt to achieve earlier diagnosis, thereby increasing the cure rate, of oat cell lung cancer. Of the 155 men who were found to have lung cancer, 27 (17%) had confirmed oat cell cancer. Only one case was diagnosed at the first examination. The other 26 cases (called incidence cancer) were diagnosed by subsequent examinations. In 24 of the 26 patients, the tumor was not found until it was advanced (Stage III), and of these patients, only one is alive at 21 months follow-up. Two tumors were diagnosed as oat cell carcinoma at an early stage (Stage I), and both patients are alive with no evidence of disease at seven and 24 months. The screening program used in this study did not succeed in detecting oat cell cancer at an early stage. 相似文献