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At least 1,531 records · Page 85Linked to original sources
PubMed1986

Architecture of the media of the arterial vessels in the dog brain: a scanning electron-microscopic study.

The architecture of the media of arterial vessels in dog brain was investigated using scanning electron microscopy. The arrangement and shape of the circularly-oriented smooth muscle cells varied with vessel diameter: The arteries (greater than 100 microns in diameter) had 4-10 layers of spindle-shaped smooth muscle cells; the muscular arterioles (30-100 microns), 2-3 layers of spindle-shaped smooth muscle cells; the terminal arterioles (10-30 microns), a compact layer of spindle-shaped smooth muscle cells with more dominant nodular or rod-like processes and thin lateral processes; and the precapillary arterioles (5-15 microns), a less compact layer of branched smooth muscle cells. Longitudinally-oriented muscles were observed in the medio-adventitial border. The distribution and arrangement of these muscles varied with vessel size: in the large arteries (greater than 300 microns in diameter), at the branching sites only; in the small arteries (100-300 microns), at both the branching and non-branching sites; in the muscular arterioles, at both the branching and non-branching sites in a reticular arrangement with some muscle cells having an "asteroid" appearance; in the terminal arterioles, only "asteroid-like" muscle cells were found at the branching and non-branching sites.

Animals↗
PubMed1993

Architectural arrangement of stages of the spermatogenic cycle within human seminiferous tubules is related to efficiency of spermatogenesis.

Stages of the spermatogenic cycle in human seminiferous tubules were evaluated in men with varied efficiencies of spermatogenesis to determine if the architectural arrangement of stages or the atypical cell types contributed to variation in sperm production rates. Testes were selected from men with low, intermediate, and high daily sperm production per g parenchyma (DSP/g). Round tubular cross sections were photographed by bright-field microscopy. Stages were identified for each cross section by two observers and the number of stages represented in each cross section was recorded. Number of stages per cross section in men with low efficiency of spermatogenesis were significantly (P < 0.05) fewer than men with intermediate and high efficiency of spermatogenesis. Further, the percentage of stages with atypical cell types in men with high DSP/g was significantly (P < 0.05) higher than men with low DSP/g. There was a significant relationship (P < 0.01) between the percentages of stages with atypical cell types per stage and number of stages per cross section. The atypical cell types appear to result from high density of stages per cross section in men with high DSP/g. There was no significant difference observed between groups for tubular volume, diameter, length, volume density, and volume density of seminiferous epithelium. However, a significant (P < 0.05) positive correlation between percent seminiferous epithelium per testis with DSP/g or with the number of stages per cross section was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Architecture of the mesonephric nephron in pig and rabbit.

As a precondition for determining nephron profiles in sections, mature mesonephric nephrons from pig and rabbit embryos were isolated by a maceration technique in order to demonstrate nephron architecture, length, and diameter. In the pig the proximal tubule is largely constant. In the distal tubule the pre-attachment zone shows the greatest variation. The zone of attachment ot the corpuscle and the ventrolaterally directed post-attachment coil has a predictable course as does the collecting tubule. In contrast to earlier reports, the nephron shows no drastic differences in tubule diameter and is up to 33 mm long. The proportional length of the three major nephron segments is surprisingly constant. The rabbit nephron, although much shorter (4 mm) and simpler, with an alomst S-shaped pattern, is less easily understood in sections. Marked irregularities in its course are caused by the different behaviour of the terminal proximal segments. The distal tubule shows an ampullary dilatation in the attachment zone but can be very narrow in the pre-attachment part.

Animals↗
PubMed1977

The pigment architecture of the human occipital lobe.

With the aid of steromicroscopical examination of pigment preparations uo to 1,000 micronm thick the various areas of the occipital lobe of the human brain are described. In the occipital lobe there are three main cortical types, forming the striate, the parastriate area, and the peristriate zone. The parastriate area is a horseshoe-shaped fringe area adjacent to the primary visual field. It is conspicuously marked by a relatively dark stripe of pigmented granule cells dividing the fourth layer into a light upper, a pigmented middle, and a light lower zone, a unique feature of the parastriate area, which is not to be found in any other isocortical area. This three-fold layer disappears abruptly as one passes from the parastriate to a peristriate area, permitting the definitive determination of this boundary. The peristriate zone is quite large in the inferior and the lateral parts of the occipital lobe and comparatively small in the superior parts. Its peripheral boundaries do not coincide with the limits of the occipital lobe. Parts of the cuneus on the one side are covered by parietal and temporal areas, whereas peristriate areas on the other side penetrate widely into the temporal lobe along the medial occipitotemporal and to a lesser extent the parahippocampal gyrus. As regards pigment architecture, the peristriate zone is divisble into ten areas. A relatively simply organized area accompaines the parastriate area. The structure of the cortex changes gradually until one reaches the various fringe areas adjacent to the parietal and temporal areas. The limit adjoining the temporal areas is sharply traceable, since the lower of two light cortical stripes vanishes abruptly when passing from a peristriate to a temporal area. The most highly developed field, the area peristriata magnopyramidalis, occupies part of the inferolateral margin of the occipital lobe. It displays a wealth of large pyramids in the lower reaches of the third layer, which contain tightly packed and densely stained pigment granules forming large rounded aggregates in the basal cytoplasm. Pyramids of this type give the field a close resemblance to association fields such as the posterior speech area, where they are commonly encountered as the predominant neurons of the third layer.

Aged↗
PubMed1990

Neuronal architecture of the antennal lobe in Drosophila melanogaster.

Computer reconstruction of the antennal lobe of Drosophila melanogaster has revealed a total of 35 glomeruli, of which 30 are located in the periphery of the lobe and 5 in its center. Several prominent glomeruli are recognizable by their location, size, and shape; others are identifiable only by their positions relative to prominent glomeruli. No obvious sexual dimorphism of the glomerular architecture was observed. Golgi impregnations revealed: (1) Five of the glomeruli are exclusive targets for ipsilateral antennal input, whereas all others receive afferents from both antennae. Unilateral amputation of the third antennal segment led to a loss of about 1000 fibers in the antennal commissure. Hence, about 5/6 of the approximately 1200 antennal afferents per side have a process that extends into the contralateral lobe. (2) Afferents from maxillary palps (most likely from basiconic sensilla) project into both ipsi- and contralateral antennal lobes, yet their target glomeruli are apparently not the same as those of antennal basiconic sensilla. (3) Afferents in the antennal lobe may also stem from pharyngeal sensilla. (4) The most prominent types of interneurons with arborizations in the antennal lobe are: (i) local interneurons ramifying in the entire lobe, (ii) unilateral relay interneurons that extend from single glomeruli into the calyx and the lateral protocerebrum (LPR), (iii) unilateral interneurons that connect several glomeruli with the LPR only, (iv) bilateral interneurons that link a small number of glomeruli in both antennal lobes with the calyx and LPR, (v) giant bilateral interneurons characterized by extensive ramifications in both antennal lobes and the posterior brain and a cell body situated in the midline of the suboesophageal ganglion, and (vi) a unilateral interneuron with extensive arborization in one antennal lobe and the posterior brain and a process that extends into the thorax. These structural results are discussed in the context of the available functional and behavioral data.

Animals↗
PubMed1980

A quantitative model of the functional architecture of human striate cortex with application to visual illusion and cortical texture analysis.

Anatomical and physiological data from lower primates, and psychophysical data from humans, is used to construct a quantitative model of the local and global map structure (functional architecture) of human striate cortex. A series of successful estimates deriving from this model are reviewed, including a prediction for the width of human ocular dominance columns, which has recently been verified. A variety of perceptual phenomena are then discussed, from the point of view of cortical, rather than retinal, topography. It is suggested that the striate cortex may be viewed as a "cyclopean retina" whose non-linear map structure, summarized in terms of a concatenated complex logarithmic pattern, suggests insights into the nature of the Mackay complimentary image, the Frazer spiral, fortification illusions, and the relationship of the second order statistics of a visual stimulus to pre-attentive (textural) segmentation. Finally, the nature of neuronal representation is considered in the context of recent models of perceptual and cognitive function. It is suggested that anatomical re-mapping at successive stages of the CNS may provide a conceptual alternative to conventional single cell and connectionist models, and offers a viable approach towards a "field" theory of vision.

Afterimage↗
PubMed1994

Three-dimensional architecture of the tubular endocytic apparatus and paramembranous networks of the endoplasmic reticulum in the rat visceral yolk-sac endoderm.

The three-dimensional architecture of the tubular endocytic apparatus and the endoplasmic reticulum in the rat yolk-sac endoderm was investigated after loading with horseradish peroxidase-conjugated concanavalin A by intrauterine administration. After 30 min, small vesicles (50-150 nm in diameter), small tubules (80-100 nm in diameter) and large vacuoles (0.2-1.0 microns in diameter) in the apical cytoplasm were labeled with the tracer, but lysosomes (1.0-3.5 microns in diameter) in the supranuclear cytoplasm were not labeled until 60 min after loading. Stereo-viewing of the labeled small tubules in thick sections revealed that they were not isolated structures but formed three-dimensional anastomosing networks, which were also confirmed by scanning electron microscopy after maceration with diluted osmium tetroxide. Their earlier labeling with the endocytic tracer, localization in the apical cytoplasm and three-dimensional network formation indicated that the labeled small tubules represented tubular endosomes (tubular endocytic apparatus). These well-developed membranous networks provided by the tubular endosomes are suggested to facilitate the receptor-mediated endocytosis and transcytosis of the maternal immunoglobulin in the rat yolk-sac endoderm. Scanning electron microscopy further revealed lace-like networks of the smooth endoplasmic reticulum near the lateral plasma membrane. Their possible involvement in transport of small molecules or electrolytes is discussed.

Animals↗
PubMed1983

The tissue architecture of synovial membranes in inflammatory and non-inflammatory joint diseases. I. The localization of the major synovial cell populations as detected by monoclonal reagents directed towards Ia and monocyte-macrophage antigens.

Utilizing monoclonal reagents directed towards antigens of the monocyte-macrophage lineage and Ia antigens, the tissue architecture of synovial membranes obtained from patients with non-inflammatory joint diseases and patients with rheumatoid arthritis was studied. Emphasis was placed on the localization of the type I, type II and type III synoviocytes that previously had been defined by their cell surface phenotype with regard to the expression of monocyte-macrophage lineage (M theta) and Ia antigens as well as by their phagocytic capacity or the ability to produce glycosaminoglycans. In patients with non-inflammatory joint diseases, cells with the M theta + Ia+ (type I) phenotype constituted the majority of synoviocytes immediately adjacent to the joint cavity; cells with this phenotype were also scattered in the subsynovial tissue and in the perivascular regions. The fibroblastoid type III cells defined by the absence of both M theta and Ia antigens formed the major cell population in the subsynovial tissue in this patient group. In patients with rheumatoid arthritis, the Ia+ M theta + cells were present in a characteristic double configuration forming an intensely positive layer adjacent to the intra-articular space followed by an Ia- M theta - layer that again was succeeded by an intensely Ia+ M theta + layer. Large numbers of synoviocytes bearing M theta + Ia+ antigens were also demonstrated in the diffusely inflamed subsynovial tissue, in the perivascular regions as well as around and within lymphoid infiltrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1981

Histologic architecture of submucosal connective tissues in human eustachian tube with supplemental reference to the effects of aging.

Serial sections of 74 human eustachian tubes from 37 autopsy cases were examined microscopically to determine the histologic architecture of submucosal connective tissues. Abundant elastic fibers ran just beneath the mucosal epithelium of the eustachian tube. Two kinds of layers of collagenous fiber were observed an inner circular layer and an outer longitudinal layer. An "elastic fiber band" perfectly encircled the tubal lumen at the pharyngeal part of the eustachian tube. This band became less sharply defined at the osseous part. The two layers of collagenous fiber were contiguous, especially in the upper part of the tube, and ran from the pharyngeal orifice to the isthmus. Submucosal connective tissues were found to be undeveloped in fetal eustachian tubes. In children as well, elastic fibers were not fully developed, and circular banding of collagenous fibers was less marked. With advancing age, elastic fibers increased in number and became large and brittle. Both layers of collagenous fibers became thicker. The present data indicate that the submucosal connective tissues may play an important role in the elasticity of the eustachian tube itself and in the maintenance of the tubal framework. Gerontologic changes in the eustachian tube stroma have been considered pathophysiologically.

Adolescent↗
PubMed1991

Three-dimensional architecture of the human myosalpinx isthmus. Scanning electron microscopy after NaOH digestion and ultrasonic microdissection.

The three-dimensional architecture of the human isthmic myosalpinx is directly visualized by means of scanning electron microscopy after removal of interstitial connective tissue through NaOH maceration and ultrasound microdissection. These investigations show that the myosalpinx is composed of irregularly running bundles of smooth muscle cells, changing their orientation within the myosalpinx and displaying longitudinal, oblique and circular directions. The muscular bundles anastomose and intermingle with other bundles running at different levels in the oviduct wall, and actually give rise to a wide and complex muscular network in which no distinct layers are readily discernible. These morphological data are consistent with the physiological findings that the transport of gametes and embryo in very early stages in the isthmic portion of the oviduct tube is the result of a discontinuous pattern of forward and backward movements.

Animals↗
PubMed1988

The microvascular architecture of human malignant glioma. A scanning electron microscopic study of a vascular cast.

The three-dimensional microvascular architecture of human glioma was investigated. The results of the study, the first of its kind, suggested that the process of vascularization in glioma is based on two patterns. In a large proportion of the glioma, one pattern is similar to the vascularization observed in normal developing fetal and newborn rat brain, while in a small proportion of the glioma, another pattern including complicated vascular protrusion and spiral running, is seen.

Brain Neoplasms↗
PubMed1989

Histopathological study of alobar holoprosencephaly. 1. Abnormal laminar architecture of the telencephalic cortex.

Abnormal architecture of the telencephalic cortex was studied in six autopsy specimens of alobar holoprosencephaly by histopathological, electron microscopic and immunohistochemical methods. Several common abnormalities are described and their significance discussed. In all of the specimens, the cortices showed excessive thickness and abnormal lamination with a middle cellular layer and an external sparse layer, indicating disturbance of neuronal migration. Neurons of the external sparse layer were segmented into irregularly arranged groups, suggesting disturbance of tissue organization. In three specimens, the internal pyramidal layer contained numerous abnormal glomerular structures which consisted of fine dendrites and axons.

Abnormalities, Multiple↗
PubMed1984

Architectural pattern of gastric adenocarcinoma--a 3-dimensional reconstruction study.

The 3-D microstructure of various adenocarcinomas was studied by graphic reconstruction of tubules and lumina from serial sections in four gastrectomy specimens in order to contribute to better diagnosis of the lesion by establishing the morphology of atypical glands. The cell nests in the moderately differentiated type had multiple anastomoses with one another forming a network, a pattern different from arborescent normal glands, while the lumina were separated into many small vesicles, giving the nests a porous character. Well differentiated tumours had more connections between the lumina forming a luminal network, whereas in the poorly differentiated lesions the nests also began to split into fragments. These findings provided a new viewpoint from which to establish an architectural basis for the discrimination of dysplastic from overtly malignant lesions.

Adenocarcinoma↗
PubMed1984

Atypical glands in gastric adenoma. Three-dimensional architecture compared with carcinomatous and metaplastic glands.

The pathogenetic relationship of gastric adenoma to carcinoma remains unsettled, partly due to the difficulty in discriminating between the atypical tubules of adenoma and those of adenocarcinoma. Although it has been said that this discrimination should depend not only on cellular changes but also on disorganization of glands, the latter has not been described in accurate morphological terms. In view of this, gastrectomy specimens from three patients with tubular adenoma were submitted to graphic reconstruction of atypical glands from serial sections, and were compared with well differentiated adenocarcinoma and metaplastic mucosa. Reconstruction disclosed that in adenoma, unlike in metaplastic mucosa, atypical tubules had multiple connections with adjacent ones, forming a network. At some sites of anastomosis the lumen was also connected. Though this pattern was similar to that of well differentiated adenocarcinoma, the meshes of the network were much more coarse than in the latter, showing that adenoma was a mere miniature of adenocarcinoma. The porous structure, the commonest architecture of adenocarcinoma, was never found in adenoma. There were in addition giant glands with complicated branching which, together with microcysts forming at mucosal bottom, caused convolution and twisting of tubules, producing those abnormal patterns in section on which too much stress is placed.

Adenocarcinoma↗
PubMed1989

The unraveling architecture of the junctional sarcoplasmic reticulum.

The sarcoplasmic reticulum (SR) of skeletal muscle controls the contraction-relaxation cycle by raising and lowering the myoplasmic free-Ca2+ concentration. The coupling between excitation, i.e., depolarization of sarcolemma and transverse tubule (TT) and Ca2+ release from the terminal cisternae (TC) of SR takes place at the triad. The triad junction is formed by a specialized region of the TC, the junctional SR, and the TT. The molecular architecture and protein composition of the junctional SR are under active investigation. Since the junctional SR plays a central role in excitation-contraction coupling and Ca2+ release, some of its protein constituents are directly involved in these processes. The biochemical evidence supporting this contention is reviewed in this article.

Animals↗
PubMed1995

Training-induced changes in muscle architecture and specific tension.

Five men underwent unilateral resistance training of elbow extensor (triceps brachii) muscles for 16 weeks. Before and after training, muscle layer thickness and fascicle angles of the long head of the triceps muscle were measured in vivo using B-mode ultrasound, and fascicle lengths were estimated. Series anatomical cross-sectional areas (ACSA) of the triceps brachii muscle were measured by magnetic resonance imaging, from which muscle volume (Vm) was determined and physiological cross-sectional area (PCSA) was calculated. Elbow extension strength (isometric; concentric and eccentric at 30, 90 and 180 degrees.s-1) was measured using an isokinetic dynamometer to determine specific tension. Muscle volumes, ACSA, PCSA, muscle layer thickness and fascicle angles increased after training and their relative changes were similar, while muscle and fascicle length did not change. Muscle strength increased at all velocities; however, specific tension decreased after training. Increase in fascicle angles, which would be the result of increased Vm and PCSA, would seem to imply the occurrence of changes in muscle architecture. This might have given a negative effect on the force-generating properties of the muscles.

Adult↗
PubMed1989

Influence of architectural design on nosocomial infections in intensive care units--a prospective 2-year analysis.

Nosocomial infection rates in an old intensive care ward constructed in 1924 were compared with those in a new one constructed in 1986. The nosocomial infection rate in the old unit was 34.2% and that in the new unit 31.9%, with an average of 33%. The most frequent infections were: pneumonia, urinary tract infection, septicaemia and wound infection. After transfer of the intensive care unit (ICU) the incidence and profile of nosocomial infections remained the same. These findings suggest that the influence of architectural design has little impact on the incidence of nosocomial infections.

Cohort Studies↗
PubMed1992

Optical imaging of architecture and function in the living brain sheds new light on cortical mechanisms underlying visual perception.

Long standing questions related to brain mechanisms underlying perception can finally be resolved by direct visualization of the architecture and function of mammalian cortex. This advance has been accomplished with the aid of two optical imaging techniques with which one can literally see how the brain functions. The upbringing of this technology required a multi-disciplinary approach integrating brain research with organic chemistry, spectroscopy, biophysics, computer sciences, optics and image processing. Beyond the technological ramifications, recent research shed new light on cortical mechanisms underlying sensory perception. Clinical applications of this technology for precise mapping of the cortical surface of patients during neurosurgery have begun. Below is a brief summary of our own research and a description of the technical specifications of the two optical imaging techniques. Like every technique, optical imaging also suffers from severe limitations. Here we mostly emphasize some of its advantages relative to all alternative imaging techniques currently in use. The limitations are critically discussed in our recent reviews. For a series of other reviews, see Cohen (1989).

Brain↗