摘要:

Recent ultrastructural investigations revealed early epithelial lesions in Crohn’s disease, while a specific morphological pattern was not identifiable. An increase in plasma cells, lymphocytes, macrophages, mast cells, eosinophilic and neutrophilic granulocytes, as well as focal edema and inflammation of tissue structures was seen in the lamina propria, submucosa and deeper layers. The results are consistent with the frequent discussion about a pathogenetically significant defect of the mucosal ‘barrier function’, which consists of mechanical, cellular, humoral, immunological and nonimmunological mechanisms, including different histotopographically defined lines of defense of the epithelium and lamina propria. An intact epithelial layer plays an important role as the first line of defense. It is evident that components of the epithelial barrier (absorptive cells, goblet cells, Paneth cells, M cells) show ultrastructural signs of alteration or injury, while the primary agent or event remains unknown. Another pathomechanism would be a preexisting defect in intestinal ‘barrier function’. Such a defect would result in an increased uptake of, or an inadequate immune reaction to, ubiquitously occurring antigens/agents (with genetic predisposition). However, no primary defect of epithelial or inflammatory cells has been definitely identified so far. Direct toxic damage of tissue secondarily introducing the inflammatory changes is also possible. Although the morphological alterations in Crohn’s disease are not yet clearly understood and exactly interpreted, transmission electron microscopy has been helpful in defining early lesions and has led to further knowledge about the pathogenesis of t

ISSN:1422-6405    

DOI:10.1159/000147584

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The presence and distribution of contractile cells in mature corpora lutea (CL) of pregnant and normal cycling mice were studied by transmission (TEM) and scanning (SEM) electron microscopy. In the connective tissue surrounding the CL, SEM observations made after maceration in alkali, revealed long, flat, spindle-shaped elements arranged parallel to each other, forming a continuous capsule. TEM of these elements revealed ultrastructural features of mature smooth muscle cells (SMC), as well as structures intermediate between fibroblasts, fibrocytes and SMC. Discrete bundles of SMC were seen to exit the external capsule of the CL and to penetrate the luteal tissue. The extensive branches of these bundles of SMC appeared to make contact with numerous vessels. Therefore, three-dimensional reconstruction, based on TEM and SEM analysis, revealed that the SMC of the CL were organized such that they form a wide fibromuscular skeleton around and within the luteal mass. It is possible that pulsatile or tonic contraction of this structure may help to regulate the secretory activity of the luteal tissue by modifying the pressure inside the CL.

ISSN:1422-6405    

DOI:10.1159/000147585

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

We conducted a light-microscopic histologic study of the aortic valves of 224 Syrian hamsters aged between 1 and 771 days. Most of the hamsters examined belonged to a single laboratory-inbred family with a high incidence of bicuspid aortic valves (BAVs). In 146 specimens the aortic valve was tricuspid, and in 107 of them the ventral commissure was more or less fused. The remaining 78 specimens showed a BAV with the aortic sinuses oriented ventrodorsally. In 33 BAVs a raphe was located in the ventral aortic sinus. Cartilaginous foci were present in the aortic valves of 86 specimens, 40-771 days old. The foci were located at two different sites, namely in the ventral wall of the valve and/or in the dorsal aortic sinus. Statistical analyses substantiate that (1) chondrogenesis begins earlier in BAVs, and especially in those having a raphe, than in tricuspid aortic valves and (2) the location of the cartilaginous foci is significantly associated with the morphology of the aortic valve. The present findings support the hypothesis that, in the Syrian hamster, cartilage forms in the aortic valve as a response to locally intense mechanical stimulation.

ISSN:1422-6405    

DOI:10.1159/000147586

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The mediators of axon terminals innervating the blood vessels and connective tissue compartments of rat peripheral nerves (facial, vagus and sciatic nerve) were investigated by means of double-labeling immunofluorescence. Sympathetic noradrenergic/neuropeptide-Y-immunoreactive axons innervated epi- and endoneurial arterial blood vessels; noradrenergic fibers without neuropeptide Y immunoreactivity terminated in the endoneurium between the axons of the main nerve trunk. Presumably sensory nerve terminals immunoreactive to substance P/calcitonin gene-related peptide supplied epi- but not endoneurial arteries and arterioles, and ran freely in the endoneurial space. Axons immunoreactive to vasoactive intestinal peptide innervated epineurial blood vessels of the facial and vagus nerve but were absent from the vasa nervorum of the sciatic nerve. The findings are in line with the concept, based upon previous pharmacological experiments, of a tonic constrictory and dilatory innervation of vasa nervorum. However, as judged from the distribution patterns of the neurochemically distinct axonal populations, vascular segments of different connective tissue compartments (epi- versus endoneurial) and body regions (sciatic versus cranial nerves) are differentially addressed by each of these axonal populations. This might have implications for the development of region-specific neuropathies.

ISSN:1422-6405    

DOI:10.1159/000147587

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Subcellular localization of vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) immunoreactivity within nerves was investigated in the lower esophageal sphincter of dogs and humans by double immunogold staining of sections prepared for electron microscopy. Coexistence of VIP and NPY immunoreactivity was clearly demonstrated in the large granular vesicles (LGVs) in axon terminals that were closely associated with the smooth muscle cells, as well as in the LGVs within the perikarya of neurons located in the myenteric plexus. Some LGVs appeared immunopositive only for VIP or NPY. This phenomenon might have been partly due to the fact that the double-labeling procedure with immunogold particles of different sizes was performed on both faces of each section. The results obtained in this study suggest that VIP and NPY are synthesized in the same neuron, stored in the same axon terminal, and released together to act on sphincter muscle cells.

ISSN:1422-6405    

DOI:10.1159/000147588

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Arginine vasopressin (AVP) is a peptide hormone which is found in neurons within the paraventricular (PVN) and the supraoptic (SON) nuclei of the hypothalamus. In fetal sheep, this neuropeptide is involved in maturational processes and adaptive responses to ‘stress’. This study examined the effect of age on the total number and distribution of AVP-containing neurons in the PVN and SON of fetal sheep and newborn lambs by quantitative light-microscopic immunocytochemistry. Serial coronal sections of hypothalami from three groups of animals were studied: fetuses at 104–109 days of gestation (n = 6) comprising the early group, fetuses at 130–139 days of gestation (n = 5) comprising the late group and newborn lambs at 12–20 postnatal days (n = 5) comprising the neonatal group. This period of development was chosen since adaptive mechanisms to stress are operative at or near the time of birth. Hypothalamic dimensions were measured to determine if maturation had an effect on the size of the AVP-containing subregions of the hypothalamus during this period of development. Dimensions included: ventricle height, optic chiasm width, distances from the dorsal margin of the ventricle to the lateral and medial margins of the optic tract, and distance between the medial margins of the optic tracts. As expected, with increase in maturational age, overall dimensions of the AVP-containing subregions increased significantly (p < 0.05). When early- and late-gestation fetuses were compared to newborn lambs, there was a significant increase in the total number of immunoreactive neurons in both the PVN (p < 0.01, Anova) and SON (p < 0.001, Anova) with age. With advancing age, we also observed an increase in the density of AVP neurons in the middle subregion of the PVN and in the midrostral subregion of the SON. These data suggest that, during the late gestational and early postnatal period, de novo synthesis of AVP genes occurs in these hypothalamic nuclei. This study provides a baseline for further investigation to study the effects of stress on these neurons in the developing ovine fetus and new

ISSN:1422-6405    

DOI:10.1159/000147589

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

This study describes the ultrastructural and morphometric changes in the hypothalamic paraventricular nucleus (PVN) of the streptozotocin-induced diabetic rat. During the acute phase (3 days after induction of diabetes), dendrites were swollen and appeared to have a watery cytoplasm. The affected dendrites were postsynaptic to seemingly normal axon terminals. During the intermediate phase (1-9 months after induction of diabetes), the neuronal somata contained numerous vacuoles of various sizes which were probably formed from dilated rough endoplasmic reticulum. Several unidentifiable vacuolated profiles were also seen in the neuropil. During the late phase (12 months after induction of diabetes) electron-dense dendrites and axon terminals were readily encountered in the neuropil. Most of the electron-dense dendrites were postsynaptic to normal as well as electron-dense axon terminals. Some of the electron-dense axon terminals formed axosomatic synapses with seemingly normal somata. Perivascular glial cells in the neuropil were in the process of phagocytosis. At 1-12 months of diabetes, the sizes of the somata and nuclei of PVN neurons were significantly increased in comparison with age-matched control rats.

ISSN:1422-6405    

DOI:10.1159/000147590

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The left ophthalmic artery (OA) of a Caucasian male originated from the transverse portion of the cavernous part of the internal carotid artery (ICA), indicating the persistence of a dorsal OA. It entered the orbit through the most medial part of the superior orbital fissure, close to the medial aspect of the ophthalmic nerve. In the orbital cavity, the OA crossed above the optic nerve to reach the medial wall of the orbit. At the medial end of the upper eyelid it anastomosed with the angular artery and thereafter divided into the dorsal nasal and supratrochlear arteries. Whereas the right OA did not present any irregularities, some additional anatomical variations, above all a bilateral pterygospinosus muscle, were found in this individual. Since except the existence neither the course and branching pattern of a persistent dorsal OA nor its occurrence together with other varieties have been previously reported in man, phylogenetic and ontogenetic aspects of this aberrant vessel are discussed.

ISSN:1422-6405    

DOI:10.1159/000147591

出版商:S. Karger AG    

年代:1994

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147592

出版商:S. Karger AG    

年代:1994

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147593

出版商:S. Karger AG    

年代:1994

数据来源: Karger