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PubMed2000

Diffusion-reorganized aggregates: attractors in diffusion processes?

A process based on particle evaporation, diffusion, and redeposition is applied iteratively to a two-dimensional object of arbitrary shape. The evolution spontaneously transforms the object morphology, converging to branched structures. Independently of initial geometry, the structures found after a long time present fractal geometry with a fractal dimension around 1.75. The final morphology, which constantly evolves in time, can be considered as the dynamic attractor of this evaporation-diffusion-redeposition operator. The ensemble of these fractal shapes can be considered to be the dynamical equilibrium geometry of a diffusion-controlled self-transformation process.

Journal Article↗
PubMed2002

Dwarfism in insular sloths: biogeography, selection, and evolutionary rate.

The islands of Bocas del Toro, Panama, were sequentially separated from the adjacent mainland by rising sea levels during the past 10,000 years. Three-toed sloths (Bradypus) from five islands are smaller than their mainland counterparts, and the insular populations themselves vary in mean body size. We first examine relationships between body size and physical characteristics of the islands, testing hypotheses regarding optimal body size, evolutionary equilibria, and the presence of dispersal in this system. To do so, we conduct linear regressions of body size onto island area, distance from the mainland, and island age. Second, we retroactively calculate two measures of the evolutionary rate of change in body size (haldanes and darwins) and the standardized linear selection differential, or selection intensity (i). We also test the observed morphological changes against models of evolution by genetic drift. The results indicate that mean body size decreases linearly with island age, explaining up to 97% of the variation among population means. Neither island area nor distance from the mainland is significant in multiple regressions that include island age. Thus, we find no evidence for differential optimal body size among islands, or for dispersal in the system. In contrast, the dependence of body size on island age suggests uniform directional selection for small body size in the insular populations. Although genetic drift cannot be discounted as the cause for this evolution in body size, the probability is small given the consistent direction of evolution (repeated dwarfism). The insular sloths show a sustained rate of evolution similar to those measured in haldanes over tens of generations, appearing to unite micro- and macroevolutionary time scales. Furthermore, the magnitude and rate of this example of rapid differentiation fall within predictions of theoretical models from population genetics. However, the linearity of the relationship between body size and island age is not predicted, suggesting that either more factors are involved than those considered here, or that theoretical advances are necessary to explain constant evolutionary rates over long time spans in new selective environments.

Animals↗
PubMed1989

Changing pattern of cutaneous tuberculosis. A prospective study.

During the past 3 years, we have seen a changing pattern of cutaneous tuberculosis, in which its incidence was recorded to show an upward trend affecting predominantly the adult men. The latter was true in reinfection--lupus vulgaris and tuberculosis verrucosa cutis, whereas a substantial number of children were victims of reactivation--scrofuloderma. The duration of the disease was usually short in reactivation tuberculosis. Its clinical expression, however, conformed largely to the ritual text except that apple-jelly nodules were infrequently demonstrated. Similarly, the morbidity was low. The affliction of the extremities in lupus vulgaris, in particular, was a contrasting feature. The histopathology invariably either confirmed or supplemented the clinical impression. The ultimate confirmation of cutaneous tuberculosis was done only by the demonstration of Mycobacterium tuberculosis in smears, or its recovery in vitro. In view of the limitations of the preceding parameters, the diagnosis may reasonably be made based on the history and evolution of the disease, cardinal morphologic features of reinfection and reactivation tuberculosis, and histopathologic characteristics. A response to antitubercular drugs may be of assistance.

Diagnosis, Differential↗
PubMed2006

Morphological integration and adaptation in the snake feeding system: a comparative phylogenetic study.

A long-standing hypothesis for the adaptive radiation of macrostomatan snakes is that their enlarged gape--compared to both lizards and basal snakes--enables them to consume "large" prey. At first glance, this hypothesis seems plausible, or even likely, given the wealth of studies showing a tight match between maximum consumed prey mass and head size in snakes. However, this hypothesis has never been tested within a comparative framework. We address this issue here by testing this hypothesis in 12 monophyletic clades of macrostomatan snakes using recently published phylogenies, published maximum consumed prey mass data and morphological measurements taken from a large sample of museum specimens. Our nonphylogenetically corrected analysis shows that head width--independent of body size--is significantly related to mean maximum consumed prey mass among these clades, and this relationship becomes even more significant when phylogeny is taken into account. Therefore, these data do support the hypothesis that head shape is adapted to prey size in snakes. Additionally, we calculated a phylogenetically corrected morphological variance-covariance matrix to examine the role of morphological integration during head shape evolution in snakes. This matrix shows that head width strongly covaries with both jaw length and out-lever length of the lower jaw. As a result, selection on head width will likely be associated with concomitant changes in jaw length and lower jaw out-lever length in snakes.

Adaptation, Physiological↗
PubMed2006

Different breakage-prone regions on chromosome 1 detected in t(11;14)-positive mantle cell lymphoma cell lines and multiple myeloma cell lines are associated with different tumor progression-related mechanisms.

To better define secondary aberrations that occur in addition to translocation t(11;14)(q13;q32) in mantle cell lymphomas (MCL) and in multiple myelomas (MM), seven t(11;14)-positive MCL cell lines and four t(11;14)-positive MM cell lines were analysed by fluorescence R-banding and spectral karyotyping (SKY). Compared with published data obtained by G-banding, most chromosome aberrations were redefined or further specified. Furthermore, several additional chromosome aberrations were identified. Thus, these cytogenetically well defined t(11;14)-positive MCL and MM cell lines may be useful tools for the identification and characterization of genes that might be involved in the pathogenesis of MCL and MM, respectively. Since MCL and MM were found to have different alterations of chromosome 1, these were investigated in more detail by fluorescence in situ hybridization (FISH) and multicolor banding (MCB) analyses. The most frequently altered and deletion-prone loci in MCL cell lines were regions 1p31 and 1p21. In contrast, breakpoints in MM cell lines most often involved the heterochromatic regions 1p12-->p11, and the subcentromeric regions 1q12 and 1q21. These data are in accordance with previously published data of primary lymphomas. Our findings may indicate that different pathways of clonal evolution are involved in these morphologically distinct lymphomas harboring an identical primary chromosome aberration, t(11;14).

Cell Line, Tumor↗
PubMed1978

Skeletal differences between pygmy (Pan paniscus) and common chimpanzees (Pan troglodytes).

Skeletal dimensions of pygmy (Pan paniscus) and common (Pan troglodytes) chimpanzees were compared. Significant differences were found in the clavicles, scapulae, pelvises, and in the humerus/femur and femur head/length ratios. No significant differences were observed in long bone lengths or talar breadths. There is extensive overlap in body weights, so that the observed differences cannot be accounted for by body size alone. We conclude that pygmy and common chimpanzees are morphologically distinct. Implications for hominoid evolution are discussed.

Animals↗
PubMed1996

Genetic evidence for the subdivision of the arthropod limb into coxopodite and telopodite.

Arthropod appendages are thought to have evolved as outgrowths from the body wall of a limbless ancestor. Snodgrass, in his Principles of Insect Morphology (1935), proposed that, during evolution, expansion of the body wall would originate the base of the appendages, or coxopodite, upon which the most distal elements that represent the true outer limb, or telopodite, would develop. The homeobox gene Distal-less (Dll), which is required in the Drosophila appendages for development of distal regions, has been proposed to promote formation of telopodite structures above the evolutionary ground-state of non-limb or body wall. Here, we present evidence that another homeobox gene, extradenticle (exd), which is required for appropriate development of the trunk and the proximal parts of the appendages, represents a coxopodite gene. We show that exd function is eliminated from the distal precursors in the developing limb and remains restricted to proximal precursors throughout development. This elimination is important because, when ectopically expressed, exd prevents distal development and gives rise to truncated appendages lacking distal elements. Moreover, the maintenance of exd expression during larval stages, contrary to Dll, does not require the hedgehog (hh) signaling pathway, suggesting that the proximal regions of the appendages develop independently of hh function. Finally, we show that in the crustacean Artemia, exd and Dll are expressed in comparable patterns as in Drosophila, suggesting a conserved genetic mechanism subdividing the arthropod limb.

Animals↗
PubMedDate not supplied

[Tensional and morphologic analysis of the colonic anastomosis on 10% acetic acid induced colitis, in Wistar rats, treated with 10% aroeira-do-sertão (Myracrodruon urundeuva fr. all.) aqueous extract].

PURPOSE: Verify, from a morphologic and tensional view point, the effect of the 10% aqueous extract of aroeira-do-sertão on the colonic anastomosis, during the occurrence of 10% acetic acid induced colitis, in Wistar rats. METHODS: There were used 48 Wistar rats, distributed in two groups. All animals were subjected to induction of colitis by aqueous solution of 10% acetic acid. Twenty-four hours later, the animals were subjected to laparotomy, transverse total colotomy and end-to-end anastomosis with 5-0 polypropylene. Group A (vehicle), animals treated with carboxymethylcellulose based vehicle. Group B (aroeira), animals treated with 10% aroeira aqueous extract. Both treatments were by means of enema. Groups A and B were distributed in subgroups A3, A7, A14 and A21; B3, B7, B 14 and B21, according to the foreseen euthanasia date (days 3, 7, 14 and 21). On these dates, the animals were relaparotomized, the colonic segment containing the anastomosis was ressected subjected to the pressure test and then to the, histological analysis. For the momphologic study, the slides were dyed with hematoxilin-eosine and the healing status was evaluated based on a score chart that ranked from 0 to 16. The higher the score, the better the healing. RESULTS: On the evaluation of the morphologic study, which quantifies the evolution and degree of healing, as a final result of the healing process, the group aroeira was superior to the group vehicle (p<0.05) on the twenty-first day, showing higher velocity on tissue repair that occurs by regeneration and not by fibrosis. With respect to the tension test, there was a statistically significant difference on day 3, with predominance of the group aroeira over the group vehicle (p<0.05). CONCLUSION: The 10% aroeira-do-sertão aqueous extract, has healing activity on the colonic anstomosis during the occurrence of 10% acetic acid induced colitis. It improves the resistance to tension on the colonic anastomosis zone on the 3rd day.

Acetic Acid↗
PubMed2001

[Role of embryogenesis of the left renal vein and spermatic veins in etiopathogenesis of idiopathic varicocele].

The aim of this work was to clearly illustrate that the haemodynamic pathogenesis of the varicocele can be a consequence of a retrograde flux along the internal spermatic vein. The reflux is due to the use of a different path of drainage along the internal spermatic vein, which uses some collateral routes of the vessel, and mainly the nephrogenital branch. The diminishing pressure in the final segment of the internal spermatic vein is the focal points of the pathogenesis of the disease. The ontogenetic processes that lead to the formation of the left renal vein help in explaining the almost general one-sidedness of the disorder, its frequency and the fact that it is mostly the young who are affected by it. In fact, the variability of the timing and of the extension of the involution of the primitive venous system and of the processes of evolution which lead to the morphological definition of the tracts of the genital flow down, lead to the various manifestations of the idiopathic varicocele. This theory which also takes into account the physiological mechanisms of the venous drainage to the testicle in an anti-gravitation sense is part of the patterns that, under the diaphragm, rule the entire venous return of the blood toward to the heart.

Epididymis↗
PubMed2002

Effect of bismuth subgallate (local hemostatic agent) on wound healing in rats. Histological and histometric findings.

The aim of this research was to evaluate the effect of bismuth subgallate on wound healing. In 40 Wistar rats, two standard wounds (3.5 mm x 2 mm) were made using a biopsy punch on the back of each animal. Test wounds were filled with bismuth subgallate and control wounds with 0.9% saline. At 1, 4, 7, 11 and 18 days, the qualitative evolution of the granulation tissue morphology was observed and digitalized histologic images were evaluated. There were no significant histological differences between test and control. Histometrically, there were statistically significant differences between test and control (ANOVA--days 1 and 4; Student t test, p < 0.05--days 7, 11 and 18) in terms of the following parameters: area of ulceration--day 1; distance between epithelial edges--day 4; area of granulation tissue--days 7, 11 and 18. It was concluded that bismuth subgallate is biocompatible to the healing tissue, and did not interfere with the normal development of wound healing.

Analysis of Variance↗
PubMed2002

[Prevalence and morphology of pineal cysts discovered at pituitary MRI: review of 1844 examinations].

PURPOSE: To evaluate the frequency, morphology and clinical long term evolution of pineal cysts depicted on MRI. PATIENTS AND METHODS: one thousand eight hundred and forty four (1 532 women and 126 men) MRI examinations were retrospectively reviewed. Coronal and sagittal spin echo T1 weighted sequences without and with gadolinium injection were performed, completed with spin echo T2 weighted images when a cystic sellar lesion was suspected. A pineal cyst was diagnosed as a rounded well defined lesion, with fluid signal in an enlarged pineal gland. Follow-up examinations were performed to evaluate the efficacy of the treatment of the sellar lesion. RESULTS: Twenty one epiphyseal cysts (1.27%) were diagnosed in 20 women (1.31%) and one man (0.79%). Their size was 1,2 +/- 0,4 cm (0,3 to 2 cm). They were asymptomatic. In 10 patients, follow-up MRI examinations did not show any change in size. During the clinical follow-up, these twenty-one patients remained asymptomatic (6 months to 5 years). CONCLUSION: The incidental detection of a pineal cyst at MRI is not exceptional. This lesion's pattern appears characteristic and their reputation of benignity is confirmed in our study.

Adult↗
PubMed1991

A preliminary isoenzyme study on five species of phlebotomine sandflies in China.

During June to August, 1987, six species of phlebotomines were collected by aspirator from four localities in Beijing, Nanjiang and northwestern Sichuan Province. After morphological identification, five species viz., Phlebotomus chinensis, P. sichuanensis, Sergentomyia zhengjiani, S. khawi and S. squamirostris were studied starch gel electrophoresis in 10 enzymes for isoenzyme characterization. Among which four enzymes (MDH, PGM, PGI and alpha-GPD) showed varying degrees of differences. The characteristic enzyme locus of PGM can be used to identify P. sichuanensis (Sichuan strain) from P. chinensis (Sichuan and Beijing strains) two vectors of Chinese visceral leishmaniasis, the pharyngeal armatures and spermathecae of which are morphologically resemble in females. The locus of PGM for genotype AA is over 77% in P. chinensis compared with 8.3% in P. sichuanensis and genotype DD is 75% in P. sichuanensis compared with negative in P. chinensis. Distinct enzymatic differences were demonstrated between genera Phlebotomus and Sergentomyia. The alleles of MDH-1 were 100 and 95 in genus Phlebotomus and Sergentomyia respectively, meanwhile in alpha-GPD the alleles were at 100 and 97 respectively except S. squamirostris. In PGI it showed polymorphic with two loci and more alleles in Phlebotomus and monomorphic with only one locus in Sergentomyia. The similar enzyme phenotype between morphologically distinct species, S. zhengjiani and S. khawi shown that the uncorrespondence between morphological and genetic characters in evolution is present in some cases of phlebotomine such as in other insects.

Animals↗
PubMed1990

[Cytochemical studies on the formation of multivesicular bodies in Leydig cells].

Multivesicular bodies were observed frequently in electron microscope photographs of Leydig cells from normal adult rat testes. Their formation, evolution and fate were analyzed morphologically in preparations treated to show cytidine monophosphatase (CMPase) activity and in animals sacrificed at various time intervals ranging from 5 min to 2 hrs after a single intratesticular injection of cationic ferritin (CF). Analysis of morphological and cytochemical data led to the following interpretation for the origin and fate of the multivesicular bodies in Leydig cells. The formation of multivesicular bodies in Leydig cells can be divided into three steps. Step 1, some endocytic vacuoles in Golgi region fuse with small vesicles to form pre-multivesicular bodies. Step 2, the pre-multivesicular bodies fuse together to form pale multivesicular bodies which are characterized by their large size, pale matrix and paucity of internal vesicles. Step 3, the pale multivesicular bodies remove their surplus enveloping membrane to become dense multivesicular bodies which are characterized by their smaller size, dense matrix and filling with internal vesicles. The pre-multivesicular bodies and pale multivesicular bodies do not contain hydrolytic enzymes, the dense multivesicular bodies acquire their hydrolytic enzymes by fusion with lysosomes and show CMPase activity. The dense multivesicular bodies often show a very close association with autophagosomes, and they might be involved in the autophagic activity of Leydig cells.

Animals↗
PubMed1989

The effect of short-wavelength ultraviolet light on antigens, lectin receptors and the ultrastructure of Crithidia fasciculata.

Crithidia fasciculata is an important trypanosomatid parasite commonly affecting insects and is used extensively as a model for the study of the biochemistry, ultrastructure and organization of the kDNA network of trypanosomatids. The present study describes the evolution of UV-induced morphological changes detectable by transmission electron microscopy in Crithidia fasciculata. Although only rare and minor changes in kinetoplast DNA were demonstrable 7 h after UV irradiation, alterations of this organelle were present in almost all flagellates observed 24 h and 48 h after irradiation. Other cell structures were apparently undamaged. Ultrastructural changes in kDNA did not correspond to changes in antigenicity of protein bands in western blotting against serum from Chagas' disease patients or in the presence of 3 different lectin receptors on the surface of the parasite.

Animals↗
PubMed1989

[Immunohistochemical analysis of ras gene expression in human melanomas and melanocytic nevi].

Ras oncogene expression of malignant melanoma and melanocytic nevus has been immunohistochemically analyzed using monoclonal antibodies which were generated against ras oncogene products (p21ras) derived from Harvey sarcoma virus. Freshly frozen tissues from 11 melanomas and 8 melanocytic nevi were examined by immunofluorescence method, and also, formalin-fixed and paraffin-embedded tissues from 26 melanomas and 24 melanocytic nevi by ABC method. There existed differences of p21ras expressions by the type of melanoma that nodular melanoma, epithelioid cell type melanoma, and deeply invaded melanoma revealed higher reactivity with anti-p21ras monoclonal antibody than the other types. The reactivity of melanomas were, thus, well correlated to the degree of malignancy of melanomas. In melanocytic nevi, dermally located nevus cells had relatively strong reactivity with anti-p21ras monoclonal antibody in contrast to junctional type nevi and the nevus cells located in the epidermis in compound type nevi which did not show the positive reaction. p21ras expressions in both melanomas and melanocytic nevi may represent a marker of the immature state of cells corresponding to early stages of the melanocyte evolution as well as the morphologic and enzymologic characteristics.

Adolescent↗
PubMedDate not supplied

[Pathogenesis of primary lymphedemas].

The role of the involvement of regional limph-node relays is already known, in the genesis of secondary lymphatic oedemas. With regard to the primary lymphatic oedemas however the role of regional lymph-nodes is considered to be limited. Following a complex investigation of an important clinical material the authors conclude that, in cases of primary lymphatic oedemas the determinat lesion is in the regional lymph nodes, and that it consists in an alteration of the filtration capacity, as well as in a reduction of the processing capabilities by the lymph nodes of the lymph flowing from the afferent lymph vessels. Simultaneously with the functional alterations lymphography revealed a series of changes, and macro- and microscopic examination also showed morphological pathologic alterations. The clinicat evolution and the prognosis of the oedema in the limb involved will depend on the extension and the evolution of these lesions.

Adolescent↗
PubMedDate not supplied

Introduction to the study of adult T-cell leukemia and HTLV-I sero-positivity in Romania.

The study presents 6 cases of leukemia/lymphoma (with mature T-cells) corresponding to the diagnostic criteria of adult T-cell leukemia (ATL): adult age onset of leukemia/lymphoma, organomegaly but normal mediastinum, leukemic cells with typical morphology and phenotype hypercalcemia. The evolution of disease was severe of subacute with resistance or partial response to therapy. The virologic assays were positive according to the ELISA test in four cases of which two presented, according to the Western blot assay, HTLV-I infection. The epidemic aspect of this infection is discussed as well as the possibility of contamination and the geographic spread of the places of origin of the patients. Emphasis is laid on the young age (22-26 years) of three of the patients infected, as a peculiar feature of the disease in Romania.

Adult↗
PubMed2006

Nuclear markers reveal that inter-lake cichlids' similar morphologies do not reflect similar genealogy.

The apparent inter-lake morphological similarity among East African Great Lakes' cichlid species/genera has left evolutionary biologists asking whether such similarity is due to sharing of common ancestor or mere convergent evolution. In order to answer such question, we first used Geometric Morphometrics, GM, to quantify morphological similarity and then subsequently used Amplified Fragment Length Polymorphism, AFLP, to determine if similar morphologies imply shared ancestry or convergent evolution. GM revealed that not all presumed morphological similar pairs were indeed similar, and the dendrogram generated from AFLP data indicated distinct clusters corresponding to each lake and not inter-lake morphological similar pairs. Such results imply that the morphological similarity is due to convergent evolution and not shared ancestry. The congruency of GM and AFLP generated dendrograms imply that GM is capable of picking up phylogenetic signal, and thus GM can be potential tool in phylogenetic systematics.

Africa, Eastern↗