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PubMed1984

[Erythema nodosum and Crohn's disease].

Erythema nodosum was found on 11 out of 106 patients with Crohn's disease (10.4%), being the most common skin complication after the perianal ones. Women were affected more often than men (2.7:1) and most of the patients were above 15 and below 40 years of age. Patients with ileocolic lesions were more often affected than those with lesions confined to the small bowel. No cases of erythema nodosum were found in association with granulomatous colitis, as opposed to other authors experience. The eruption was usually related to the periods of active inflammatory bowel disease but not to the administration of salazopyrine. The morphology and evolution of the lesions was typical of erythema nodosum and joint involvement was almost constant. The differential diagnosis with other nodular eruptions that can occur in association with Crohn's disease are discussed and hypothetical common etiopathogenic factors to both Crohn's disease and erythema nodosum are briefly considered. The relevant literature is reviewed and commented upon.

Adolescent↗
PubMed1984

[Parietal multilocular arachnoid cysts in adults. 2 cases].

Two cases of multiloculated arachnoid cysts of the parietal area are discovered at the ages of 57 and 69. The terrain, the situation and the morphology, the evolution, distinguish these lesions from the more classic cysts of the sylvian fissure. Their pathophysiology is discussed anatomically, these cysts are not far from the post traumatic ones, developing in childhood.

Aged↗
PubMed1982

[Roussy-Levy hereditary areflexic dysstasia. Its historical relation to Friedreich's disease, Charcot-Marie-Tooth atrophy and Dejerine-Sottas hypertrophic neuritis; the present status of the original family; the nosologic role of this entity].

This survey of Roussy-Lévy disease begins with an historical account of the three neurological conditions from which this entity has been separated: Friedreich disease, described in 1861-1863, which proved with time to be a genuine anatomoclinical disorder: Charcot-Marie-Tooth atrophy, described in 1886, particular because of its morphology and evolution but due to various processes: Dejerine-Sottas hypertrophic neuritis, described in 1893, which was the first variant to be individualized within the heterogenous group of primary and familial hypertrophic neuritis. The initial description of Roussy-Lévy disease--in 1926, 1932, and 1934--and the controversies raised by this concept are recalled as well as the present state of the original family: five out of seven members have been examined since 1956 and it has been demonstrated that they are suffering from a form of hypertrophic neuritis. However it is this author's opinion that the concept of an autonomous Roussy-Lévy disease within hypertrophic neuritis is justified by the following criteria: dominant transmission, very precocious onset, extreme slowness of the evolution, remarkable benignity of the prognosis.

Ataxia↗
PubMed1980

The "early" ulcerative lesion of Crohn's disease: correlative light- and scanning electron-microscopic studies.

Submucosal edema and lymphectasia have traditionally been considered the earliest recognizable alterations in Crohn's disease. However, a characteristic pattern of ulceration grossly resembling the oral lesions of aphthous stomatitis is believed by others to be the earliest macroscopic lesion. We have studied 50 consecutively accessioned surgical specimens with Crohn's disease in an effort to define more thoroughly the frequency, distribution, and morphology of these "aphthoid" ulcers. The scanning electron microscope (SEM) was used in the study because an understanding of the morphology and evolution of these lesions requires an appreciation of their three-dimensional configuration. Typical "aphthoid" ulcers were identified in 35 of the 50 specimens studied. Grossly the typical ulcerative lesion varies from barely visible up to 3 mm in diameter. They have a characteristic light-microscopic appearance consisting of focal ulceration usually overlying an aggregate of lymphoid tissue. The SEM was helpful in identifying the smallest of these lesions and was especially useful in defining a variety of villous abnormalities in the small bowel mucosa adjacent to the ulcers.

Adolescent↗
PubMed1994

Hox genes and growth: early and late roles in limb bud morphogenesis.

In recent years, molecular analysis has led to the identification of some of the key genes that control the morphogenesis of the developing embryo. Detailed functional analysis of these genes is rapidly leading to a new level of understanding of how embryonic form is regulated. Understanding the roles that these genes play in development can additionally provide insights into the evolution of morphology. The 5' genes of the vertebrate Hox clusters are expressed in complex patterns during limb morphogenesis. Various models suggest that the Hoxd genes specify positional identity along the anteroposterior (A-P) axis of the limb. Close examination of the pattern of Hoxd gene expression in the limb suggests that a distinct combination of Hoxd gene expressed in different digit primordia is unlikely to specify each digit independently. The effects of altering the pattern of expression of the Hoxd-11 gene at different times during limb development indicate that the Hoxd genes have separable early and late roles in limb morphogenesis. In their early role, the Hoxd genes are involved in regulating the growth of the undifferentiated limb mesenchyme. Restriction of the expression of successive 5' Hoxd genes to progressively more posterior regions of the bud results in the asymmetric outgrowth of the limb mesenchyme. Later in limb development, Hoxd genes also regulate the maturation of the nascent skeletal elements. The degree of overlap in function between different Hoxd genes may be different in these early and late roles. The combined action of many Hox genes on distinct developmental processes contribute to pattern asymmetry along the A-P axis.

Animals↗
PubMed1994

[Haemangiomas and vascular malformations of the nose].

After discussing histogenetic, morphologic and evolutive aspects that distinguish haemangiomas from vascular malformations, the Authors affirm the important role that haemodynamic stimuli take on in the evolution of the latter. Vascular malformations are subdivided into capillary, venous and arterial, according to where they originate in the vascular tree. With reference to haemangiomas, the Authors underline the importance of steroid therapy and the necessity to resort to integrative surgical procedure in those cases which do not respond satisfactorily to steroid therapy. The different procedures to be performed, according to dimension and localization of the haemangiomas, are explained in detail. In capillary vascular malformations of small significance from a haemodynamic and evolutionary point of view, comparable to a slightly pathological capillary network, the surgeon often faces complex reconstructive problems which involve, however, only the tegument. These can be resolved using forehead flaps, if necessary, expanded. Arteriovenous vascular malformations are more problematic and therefore require greater surgical skill, prone as they are to progressive expansion and aggravation brought about by haemodynamic mechanisms.

Angiography↗
PubMed1994

Morphology and changes in Clara cells in the foetal bronchioles of Swiss mice.

In this work we have studied the morphology and evolution of Clara cells in the bronchiolar mucosa of lungs from 63 Swiss mice foetuses that were classified into three groups according to age (14, 16 and 18 days). A control group composed of 21 15-day-old Swiss mice was also studied. The most salient feature of the Clara cells observed was the occurrence of two types of secretory granules and a large smooth endoplasmic reticulum. On the other hand, the Clara cells of the control group had a single secretory granule. Clara cells thus seem to take part in bronchiolar metabolism, as they were quite abundant in the early foetal groups and diminished as birth approached. This cell decrease was confirmed by the control group (15-day-old mice), the bronchioles of which contained scant cells and numerous ciliated cells.

Animals↗
PubMed1997

[Dermatitis artefacta].

We report a case of a 29-year-old man presenting skin ulcerations on both sides of the mandible. The diagnosis of dermatitis artefacta was based on the morphology and evolution of the lesions, on the patient's borderline personality, on the objects found in his possession, and a later admission of having an involvement in the aggravation of the lesions.

Adult↗
PubMed1997

[Single-photon emission-computed tomography in the diagnosis of cerebrovascular diseases].

BACKGROUND: SPECT-HM-PAO allows to detect the regional cerebral blood flow and total diminution of the brain perfusion still before morphological substrate evolution in CT scan, without invasive technologies. SEARCH GOAL: The authors have analyzed data obtained by SPECT-99mTc HM-PAO in the group of 46 patients suffering from cerebrovascular disorders and they have compared them with results aimed by CT scans. Both, the SPECT-99mTc HM-PAO and CT scan were performed within 48 hours or later after the onset of the stroke; some of CT scans were repeatedly performed. RESULTS: They discovered 40 positive and 6 negative SPECT-HM-PAO findings, 26 positive and 20 negative CT scans. SPECT investigation more frequently discovers circulatory failures in the clinically altered hemisphere than the CT scan does in a substrate; SPECT discloses hypoperfusion of the clinically unaltered hemisphere if silent hypoperfusion is present. The ipsilateral foci of CT substrates were significantly less frequently observed (p < 0.001) than some ipsilateral regional hypoperfusions. Not only the number, but also size and extent of hypoperfusional foci searched by SPECT are significantly higher and wider than the numbers and dimensions of substrates observed by CT (p < 0.001). CONCLUSION: CT scan diagnostic possibilities are restricted by the time factor (CT examinations performed within 48 hours since the onset of the stroke are significantly less frequently positive than those performed later-p < 0.001). SPECT examination has not such a limiting time factor (p > 0.05). MEANING: Hence SPECT-HM-PAO renders early, long lasting and wide information on the restriction of the overall and regional perfusion, independently of the fact as to whether the reduction of cerebral perfusion is, or is not going to result in ischemic necrosis and/or ischemic sclerosis. SPECT renders correlation of the perfusion disorder earlier, wider in space, and more frequently than the CT scan, and therefore it is a prerequisite to the disclosure of the mentioned silent focal blood flow reductions. (Graph 12, Fig. 3, Ref. 4.)

Adult↗
PubMed1997

[Progestin-induced mammary adenocarcinomas in BALB/c mice. Progression from hormone-dependent to autonomous tumors].

We have developed an experimental model in which the administration of progestins induces mammary tumors in female virgin BALB/c mice. In this paper we review the morphological and biological features of progestin-induced tumors, such as estrogen receptor (ER) and progesterone receptor (PR) patterns of expression, hormone dependence and epidermal growth factor receptors (EGF-R) we also examine our data concerning the systemic effects of medroxyprogesterone acetate (MPA) as regards its stimulating EGF synthesis in salivary glands and its subsequent increase in serum. This growth factor seems to play an important role in the induction of mammary tumors. Direct MPA proliferative effects mediated by PR were demonstrated using primary cultures of progestin-dependent (PD) mammary tumors. Antiprogestins inhibited cell growth beyond control values, suggesting that PR are involved in cell proliferation even in the absence of the ligand. Progesterone-independent (PI) tumors expressing high levels of PR and ER are also inhibited by estrogen or antiprogestin treatment, suggesting that PR are involved in the control of autonomous tumor growth. Estrogen-resistant variants may be selected which may revert to an estrogen-sensitive phenotype after several transplants in untreated mice. The similarities between the tumors obtained with this model and human breast cancer as regards morphological features, evolution and the regulation of growth control converts this model into a useful tool to explore the mechanisms related with acquisition of hormone independence and autonomous tumor growth.

Adenocarcinoma↗
PubMed1996

Angiogenesis in the gonadal capillary network of the chick embryo.

Seventy-one chick embryos of both sexes at the 35 Hamburger and Hamilton (H-H) developmental stage were processed for scanning electron microscopy of vascular corrosion casts and of critical point dried specimens, as well as transmission electron- and light microscopy, in order to study the angiogenic structures. The gonadal subepithelial capillary network was located at the level of the tunica albuginea under the covering epithelium. The casts showed a densely-meshed capillary network and numerous sprouting (nodular protrusions or capillary sprouts) and non-sprouting (enlarged vessels and angiogenic holes) angiogenic structures that were randomly distributed and mixed. Four types of angiogenic holes were encountered in the casts: primary (diameter < 2.5 microns), secondary (diameter > 2.5 microns), tertiary (variable diameter and circular narrowings on one side), and open angiogenic holes. We suggest that the different morphologies reflect evolution of these holes. Furthermore, the open angiogenic hole would probably either form nodular protrusions at its open ends, which tend to join with other nodular protrusions and neighboring capillaries and form new vessels; or there would be fusion with two or more neighboring open holes. Correlative critical point dried sections showed fenestrations in the capillary walls and transcapillary pillars that corresponded to the angiogenic holes found in the casts. Ultrathin sections of the vessels presented typical characteristics of growing endothelium: large nuclei with loosely textured chromatin, abundant cytoplasm rich in cell organelles and intraluminal endothelial processes.

Animals↗
PubMed1998

The molecular evolution of development.

Morphological differences between species, from simple single-character differences to large-scale variation in body plans, can be traced to changes in the timing and location of developmental events. This has led to a growing interest in understanding the genetic basis behind the evolution of developmental systems. Molecular evolutionary genetics provides one of several approaches to dissecting the evolution of developmental systems, by allowing us to reconstruct the history of developmental genetic pathways, infer the origin and diversification of developmental gene functions, and assess the relative contributions of various evolutionary forces in shaping regulatory gene evolution.

Animal Population Groups↗
PubMed1992

Origin of Gila seminuda (Teleostei: Cyprinidae) through introgressive hybridization: implications for evolution and conservation.

Morphological and genetic characters from cyprinid fishes of the genus Gila were examined to assess a hypothesized hybrid origin of Gila seminuda from the Virgin River, Arizona-Nevada-Utah. The presumed parents, Gila robusta robusta and Gila elegans, are clearly differentiated from one another based on morphology, allozymes, and mtDNA haplotypes. G. seminuda is morphologically intermediate and polymorphic at allozyme loci diagnostic for the parental species. Restriction endonuclease analysis of mtDNA showed G. seminuda nearly identical to G. elegans. These results support an origin of the bisexual taxon G. seminuda through introgressive hybridization. The Gila population in the Moapa River, Nevada, also appears to be of hybrid origin and is considered a distinctive population of G. seminuda. Inter-specific hybridization is potentially an important mode of evolution among western North American fishes, and valid species of hybrid origin may exist in other groups as well. Consideration of this mode of evolution argues for the need to conserve entire species complexes.

Animals↗
PubMed2005

Fishing for the secrets of vertebrate evolution in threespine sticklebacks.

The threespine stickleback (Gasterosteus aculeatus) is rapidly emerging as a new model genetic system to study questions at the interface of evolution and development. The relatively rapid and recent diversification of this small teleost fish, combined with the development of genetic and genomic tools for this fish, provides an unprecedented opportunity to identify the genetic and molecular basis of morphological variation in natural populations of vertebrates. Recently, the genes underlying two different adaptive morphological traits in stickleback have been identified. This work has provided answers to four longstanding questions in the field of evolution and development: (1) How many genes underlie morphological variation in natural populations? (2) What are the genes that underlie morphological variation in natural populations? (3) Do coding or regulatory mutations underlie morphological evolution? (4) What is the molecular and genetic basis of parallel morphological evolution? Because stickleback populations also display natural variation in morphology, life history, physiology, and behavior, extending the approaches used to identify the genetic basis of morphological variation in sticklebacks to other phenotypes is sure to yield further important insights into the genetic and developmental basis of diversity in natural populations.

Adaptation, Biological↗
PubMedDate not supplied

Defining phyla: morphological and molecular clues to metazoan evolution.

None of the supraspecific taxonomic categories can be defined objectively. Each taxon should of course be monophyletic, but there is no morphological or molecular character that identifies, for example, the phylum level. This has led some authors to abandon the Linnaean categories, but they appear to be practical "handles" in daily communication. It has been proposed that each phylum exhibits a characteristic Bauplan, but the identification of such "types" have in practice proved difficult or impossible for several phyla. Monophyly of some of the approximately 30 morphology-based phyla has been put in question by molecular studies, but recent reports clearly show that the 18S rRNA molecule, which has been used extensively in phylogenetic analyses, cannot be used alone in identifying phyla (or other higher taxonomic groups). Some higher taxa, for example Chordata, Vertebrata, and Echinodermata, consistently show up as monophyletic in the analyses, whereas molluscan and annelidan subgroups just as consistently are mixed with each other and with a number of other protostomian phyla in varying patterns.

Animals↗
PubMed2006

The effects of switching behavior on the evolutionary diversification of generalist consumers.

Mathematical models of consumer-resource systems explore the evolution of a morphological trait that determines two resource acquisition rates in a generalist consumer. The consumer also has the ability to adjust its relative consumption of the two resources via behavioral (or developmental) plasticity subject to a trade-off. The analysis examines both stable systems and those with sustained fluctuations in abundance. In both cases, it seeks to determine how the behavioral choice affects the evolution of the morphological characters. The presence of adaptive switching behavior transforms the shape of the relationship between the morphological character and fitness in a manner that usually leads to evolution of two or more morphological types. As in models without switching, the presence of sustained cycles in resource densities often allows the evolution of a generalist as well as two specialists. However, switching expands and shifts the parameter regions yielding this outcome and in some cases allows the evolution and coexistence of at least two generalists as well as the two specialists. This level of diversity supported by only two resources is not seen in the absence of behavioral choice and resource cycles. The results suggest major roles for both behavior and environmental variation in adaptive radiation.

Adaptation, Physiological↗
PubMed1994

Molecular pathways to parallel evolution: I. Gene nexuses and their morphological correlates.

Aspects of the regulatory interactions among genes are probably as old as most genes are themselves. Correspondingly, similar predispositions to changes in such interactions must have existed for long evolutionary periods. Features of the structure and the evolution of the system of gene regulation furnish the background necessary for a molecular understanding of parallel evolution. Patently "unrelated" organs, such as the fat body of a fly and the liver of a mammal, can exhibit fractional homology, a fraction expected to become subject to quantitation. This also seems to hold for different organs in the same organism, such as wings and legs of a fly. In informational macromolecules, on the other hand, homology is indeed all or none. In the quite different case of organs, analogy is expected usually to represent attenuated homology. Many instances of putative convergence are likely to turn out to be predominantly parallel evolution, presumably including the case of the vertebrate and cephalopod eyes. Homology in morphological features reflects a similarity in networks of active genes. Similar nexuses of active genes can be established in cells of different embryological origins. Thus, parallel development can be considered a counterpart to parallel evolution. Specific macromolecular interactions leading to the regulation of the c-fos gene are given as an example of a "controller node" defined as a regulatory unit. Quantitative changes in gene control are distinguished from relational changes, and frequent parallelism in quantitative changes is noted in Drosophila enzymes. Evolutionary reversions in quantitative gene expression are also expected. The evolution of relational patterns is attributed to several distinct mechanisms, notably the shuffling of protein domains. The growth of such patterns may in part be brought about by a particular process of compensation for "controller gene diseases," a process that would spontaneously tend to lead to increased regulatory and organismal complexity. Despite the inferred increase in gene interaction complexity, whose course over evolutionary time is unknown, the number of homology groups for the functional and structural protein units designated as domains has probably remained rather constant, even as, in some of its branches, evolution moved toward "higher" organisms. In connection with this process, the question is raised of parallel evolution within the purview of activating and repressing master switches and in regard to the number of levels into which the hierarchies of genic master switches will eventually be resolved.

Animals↗