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PubMed2002

[Perspective on gravitational biology of amphibians].

We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and externally, it is easy to observe their development. Consequently amphibians were the first vertebrates to have their early developmental processes investigated in space. Though several deviations from normal embryonic development occur when amphibians are raised in microgravity, their developmental program is robust enough to return the organisms to an ostensibly normal morphology by the time they hatch. Evolutionally, amphibians were the first vertebrate animal to come out of the water and onto land. Subsequently they diversified and have adaptively radiated to various habitats. They now inhabit aquatic, terrestrial, arboreal and fossorial niches. This diversity can be used to help study the biological effects of gravity at the organismal level, where macroscopic phenomena are associated with gravitational loading. By choosing different amphibian models and using a comparative approach one can effectively identify the action of gravity on biological systems, and the adaptation that vertebrates have made to this loading. Advances in cellular and molecular biology provide powerful tools for the study in many fields, including gravitational biology, and amphibians have proven to be good models for studies at those levels as well. The low metabolic rates of amphibians make them convenient organisms to work with (compared to birds and mammals) in the difficult and confined spaces on orbiting research platforms. We include here a review of what is known about and the potential for further behavioral and physiological researches in space using amphibians.

Amphibians↗
PubMed2005

[New technique to determine graft length using the proximal anastomotic system during off-pump coronary artery bypass grafting].

For determining the graft length for an aortic connector, grafts to the circumflex (Cx) and the posterior descending (PD) regions often present problems. Difficulties in determining the appropriate distance between the aorta and coronary artery have been reported to be due to changes in the morphology of the heart following the evolution of Cx and PD. We set an intermediate point (IMP) in advance and then determine graft distance in 2 steps. When using the IMP method, determination of the graft length in the Cx region is not difficult. However, attention should be paid to determine the distance between the IMP and anastomosed site without deforming the heart, as the graft length becomes shorter if the heart as a whole is pulled up by traction of the diaphragm during evolution to the PD region.

Coronary Artery Bypass, Off-Pump↗
PubMedDate not supplied

Clinicopathological evolution and multilineage involvement in erythroleukemia: report of a case.

Results of sequential chromosome and cytologic studies in a patient with erythroleukemia (EL) by FAB criteria are described here. Major karyotype aberrations (MAKA) as well as normal karyotypes were detected at presentation, when the patient showed erythroid hyperplasia with moderate leftward shift of erythropoiesis and trilineage myelodysplasia, a picture suggestive of multilineage involvement. Following conventional induction therapy, the patient entered a myelodysplastic phase (MDS) with the features of refractory anemia with excess of blasts and subsequently relapsed with classical EL with maturation arrest of erythroblasts. Chromosome studies revealed a 46, XY karyotype in the MDS phase and only MAKA at leukemia relapse. These findings provide further evidence of a multistep cytogenetic and clinicopathological evolution of EL. Concomitant cytogenetic and morphologic studies in this patient seem to suggest the presence of chromosomally abnormal erythroblasts and confirm the existence of a association between MAKA and maturation arrest of erythroblasts.

Adult↗
PubMed1991

Cardiac myofibroblasts express alpha smooth muscle actin during right ventricular pressure overload in the rabbit.

A number of changes occur in contractile proteins and mechanical performance of the heart within 2 weeks of right ventricular pressure overload in 8- to 12-week-old rabbits. These changes are accompanied by increases in collagen concentration and the ratio of type I to type III collagen. The purpose of the present study was to evaluate the evolution of these connective tissue changes morphologically and to characterize the interstitial cells that might be responsible. The myocardium is infiltrated by mononuclear inflammatory cells 2 days after banding, accompanied by focal myocyte necrosis. By 7 days, the inflammatory infiltrates subside and the damaged myocytes seen at 2 days are replaced by new collagen and a population of spindle-shaped cells, with ultrastructural features of myofibroblasts. A significant proportion of these cells contain alpha smooth muscle actin by immunohistochemical analysis. At 14 days, there is a large increase in stainable collagen with complex remodeling and reduplication of the collagen fiber network of the interstitium. Alpha smooth muscle actin-containing myofibroblasts persist, but their immunoreactivity appears reduced compared with day 7. The authors hypothesize that the interstitial fibroblasts that acquire smooth-muscle-like features in this model play a critical role in the heart's response to severe and sudden mechanical stress and are at least partly responsible for the changes in connective tissue that occur as a result of pressure overload in this model.

Actins↗
PubMed1991

[Lymphoma of the splenic mantle. Morphologic, immunologic and ultrastructural characterization of a case].

We present a splenic primary mantle lymphoma in a 64 year old woman, without peripheral lymphoadenopathy and stage IV at the moment of the diagnosis. Grossly a splenic infiltration was observed. Microscopically, a nodular lymphoma of small lymphocytes proliferating around benign germinal centers makes the diagnosis. Immunohistochemically, tumoral lymphocytes expressed SIgG/kappa and CD5 (Leu-1). Markers of follicular center origin CD10 (CALLA) were negative. According to working formulation mantle-cell lymphoma is considered a lymphoma of intermediate grade of malignancy. In our case, the morphologic, immunologic, ultrastructural findings and clinical evolution were more characteristics of a low grade lymphoma that a intermediate grade of malignancy.

Female↗
PubMedDate not supplied

[The morphopathological aspects of the trabecula in glaucoma].

The authors tackle, using the methods of classic histology, an important practical medical problem, the affection of the corneoscleral trabecula in different clinical forms of glaucoma. A study of the age-related trabecular modifications is also made. All the clinical forms of glaucoma present lesions corresponding to the evolution stage of the disease. No morphologic differences were noticed between these forms and the alterations met are similar to the senile trabecula.

Adult↗
PubMed1986

Progress of bleomycin-induced lung fibrosis in rabbits.

Progression of lung fibrosis induced in rabbits by intratracheal bleomycin (BLM, 10 mg/kg) was monitored by biochemical and morphological measurements. These indicated that the evolution of fibrosis in the rabbit was slower than in other experimental animals. Histology revealed cellular and fibrocellular lesions 4 weeks after BLM. At 8 weeks these lesions still predominated, indicating continuing active disease accompanied by a progression to fibrosis. The gradual progression of the response was reflected in alterations in lung composition. Changes in lung content of collagen, protein and DNA were evident at 8 weeks after BLM, at which time concentration (micrograms/mg dry weight) of collagen and protein were also elevated (P less than 0.05). Plasma angiotensin converting enzyme (ACE), a marker of endothelial injury, decreased 1 week after BLM (P less than 0.01) and then returned to normal, indicating that endothelial injury does not parallel the fibrotic response. In summary, the continuing active inflammation and slow progress of fibrosis induced by i.t. BLM in the rabbit suggests that this model has advantages over others for the serial study of the cellular and biochemical evolution of lung fibrosis.

Animals↗
PubMed1985

Leukocytoclastic vasculitis in urticaria induced by ultraviolet irradiation.

A 35-year-old woman would develop urticarial lesions over one to four hours after irradiation with sunlight or artificial ultraviolet radiation. Lesions could persist for days before resolving. Although lesions were morphologically typical of solar urticaria, their evolution and resolution were both much slower than expected. Histologically, the lesions showed leukocytoclastic vasculitis. This unexpected finding suggests the possibility that there may be novel mechanisms involved in the pathogenesis of some cases of solar urticaria.

Adult↗
PubMed1985

[Dysplasia and early stomach cancer].

Biopsy and operative material was used to study the incidence and significance of different degrees of dysplasia in precancerous diseases and gastric cancer, its evolution and pathognomonic features, with various morphological methods. It is shown that mild and moderate dysplasia is indistinguishable from regenerative changes in gastritis, erosions and gastric ulcer, it can undergo involution or malignization. A marker of enhanced risk of gastric cancer is severe dysplasia which is often multicentric. Among pretumor diseases, most frequently severe dysplasia is found with adenoma and gastritis of the stump. Severe dysplasia in the absence of cancer in the gastrobiopsy material makes mandatory a dynamic study with biopsies taken every three months from different regions of the mucosa. The degree of dysplasia can be objectively tested by quantitating the DNA content, and its average content can be a criterion for differential diagnosis between severe dysplasia and early cancer. The histochemical, radioautographic, and electron microscopic features of dysplasia, testifying to impaired regeneration of te epithelium, cannot serve to differentiate between severe dysplasia and cancer or to assess the risk of transition of dysplasia into cancer. The main way of solving this problem is dynamic observation.

Autoradiography↗
PubMed1981

Frog virus 3 induces a fatal hepatitis in rats.

To define its pathogenesis, the acute degenerative hepatitis caused by frog virus 3 (FV3) has been reproduced in the rat, thus facilitating a greater number of biologic explorations than in the mouse. The histologic and ultrastructural study proves a massive hepatocellular necrosis perfectly compatible with the fatal outcome of the illness 30 hours after the inoculation of one LD100. Critical analysis of the FV3 rat hepatitis induces us to advance three arguments for excluding the direct role of the virus in hepatocytolysis. (1) The hepatocyte is neither the sole nor the first intrahepatic target of the virus. The endothelial barrier and especially the Kupffer cells are completely necrosed several hours prior to the appearance of the first signs of parenchymal cell disturbances. Morphologic observations and, in particular, the evolution in the site and chronology of the cytolysis are confirmed by the variation in the activity of cathepsin D, glutamic pyruvic transaminase, and lactic dehydrogenase in serum. (2) There is a close correlation between the structural alterations in the hepatocyte nuclei and the inhibition in the synthesis of the liver macromolecules. But the discovery of a rat strain sensitive to the virus and another more resistant strain provides evidence that there is no relationship between the sensitivity to the lethal power of the FV3 and the metabolic disorders. (3) The ways in which the FV3 spreads throughout the organism do not explain why the liver is the sole organ attacked. A second etiopathogenic factor, only found in the liver, must be invoked. The possible role of the plasma complement, strongly activated, is suggested, along with that of other toxic substances which can no longer be cleared. The metabolic inhibition directly connected with the FV3 would thus result not in producing the hepatocytolysis but in rendering any cellular regeneration impossible.

Animals↗
PubMed1995

Aplastic anaemia versus hypocellular myelodysplastic syndrome.

It is important to differentiate non-dyplastic aplastic anaemia from hypocellular myelodysplastic syndrome (MDS). Four patients presenting with hypocellular bone marrow and different evolution patterns are being described. Certain morphological features and variable hypocellularity were found to be useful indices for this purpose.

Adolescent↗
PubMed2006

Adolf Remane (1898-1976) and his views on systematics, homology and the Modern Synthesis.

Adolf Remane was primarily a morphologist and systematist. In 1952, he published an influential book on the foundations of systematics and phylogenetics in which he advocated homology as the central concept of morphology and the basis of the natural system and discussed criteria serving to discriminate homology from homoplasy in great detail. During the decades when the Modern Synthesis of evolution was created, he repeatedly commented on and criticised the synthetic theory of evolution, which he never fully accepted. Remane disapproved of idealistic morphology and was strongly opposed to Lamarckian, saltationist and orthogenetic theories of evolution. Yet, while appreciating the synthetic theory's validity in the realm of speciation and microevolution, he rejected the claim that the current genetic knowledge was sufficient to explain complex morphological transformations on the basis of random mutations and selection. Instead, he seems to have favoured mutation pressure as the most important factor in macroevolution. Nevertheless, the sometimes vicious disputes between Remane and the adherents of the Modern Synthesis may at least partly have been brought about by personal factors rather than by scientific differences.

Animals↗
PubMed2005

Evolution of body size in Galapagos marine iguanas.

Body size is one of the most important traits of organisms and allows predictions of an individual's morphology, physiology, behaviour and life history. However, explaining the evolution of complex traits such as body size is difficult because a plethora of other traits influence body size. Here I review what we know about the evolution of body size in a group of island reptiles and try to generalize about the mechanisms that shape body size. Galapagos marine iguanas occupy all 13 larger islands in this Pacific archipelago and have maximum island body weights between 900 and 12 000g. The distribution of body sizes does not match mitochondrial clades, indicating that body size evolves independently of genetic relatedness. Marine iguanas lack intra- and inter-specific food competition and predators are not size-specific, discounting these factors as selective agents influencing body size. Instead I hypothesize that body size reflects the trade-offs between sexual and natural selection. We found that sexual selection continuously favours larger body sizes. Large males establish display territories and some gain over-proportional reproductive success in the iguanas' mating aggregations. Females select males based on size and activity and are thus responsible for the observed mating skew. However, large individuals are strongly selected against during El Niño-related famines when dietary algae disappear from the intertidal foraging areas. We showed that differences in algae sward ('pasture') heights and thermal constraints on large size are causally responsible for differences in maximum body size among populations. I hypothesize that body size in many animal species reflects a trade-off between foraging constraints and sexual selection and suggest that future research could focus on physiological and genetic mechanisms determining body size in wild animals. Furthermore, evolutionary stable body size distributions within populations should be analysed to better understand selection pressures on individual body size.

Animals↗
PubMed1998

Blastic Transformation in a Case of Hairy Cell Leukemia.

Background: Hairy cell leukemia (HCL) is a slowly progressive lymphoproliferative disorder that tends to afflict middle-aged adults, especially men. Blastic transformation of this form of leukemia is extremely rare. To date, a single case has been reported. Methods and Results: A case of HCL, evolving with blastic transformation after a 9- year clinical course, is reported. Routine histology, cytochemistry, flow cytometry immunophenotyping, and Southern blot analysis for B- and T-cell gene rearrangements were used in the evaluation. Although morphology at the time of presentation was characteristic of HCL, the cells were initially tartrate-resistant acid phosphatase (TRAP) negative. During a clinical course over several years, the hairy cells became progressively TRAP positive. The morphology of the leukemic cells changed 9 years after initial diagnosis, with blastic transformation and retaining strong TRAP positivity. Immunophenotypic analysis showed evolution from a characteristic hairy cell leukemic phenotype to a phenotype indicative of marked immaturity. Genotypic analysis showed an evolving pattern of immunoglobulin gene rearrangements, paralleling the morphology and phenotypic evolution and ruling out a second B-cell malignancy. Conclusions: This case report of blastic transformation in a patient with HCL is only the second such case identified in the medical literature to date.

Journal Article↗