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PubMed1981

The fibroblastic nature of dermatofibrosarcoma protuberans. A tissue culture and ultrastructural study.

Dermatofibrosarcoma protuberans has been considered to be of fibrohistiocytic or fibroblastic origin. The purpose of this paper is to identify the original cell strain from which this neoplasm derives, using tissue culture and electron microscopic methods. Thirteen cases of DFSP characterised by clinical, topographical, histological and behavioral criteria were explanted. The emigrating cells were bipolar with two opposed processed and showed a radial arrangement in respect to the explants. After the second week the distal processes tended to curve back towards the cell body forming flame-like structures. This cell morphology and cellular orientation persisted during the whole life of the culture. Electron microscopy was performed in three cases; the newly grown cells maintained an electron microscopic picture similar to that found in the original tumors. This pattern of behaviour is characteristic of fibroblastic tumors and has been found in explants of normal fibroblasts, of fibromatosis and of fibrosarcomas used as controls. On this basis, we believe that DFSP is a fibrosarcoma of the skin of low grade malignancy.

Adult↗
PubMed1995

Probing the evolution of senescence in Drosophila melanogaster with P-element tagging.

Natural populations host a wealth of genetic variation in longevity and age-specific schedules of reproduction. This variation provides critical information for inferring the evolutionary origin of senescence. Patterns of mutational effects on age-specific fecundity and survival provide additional insight to distinguish alternative models of senescence. In this study, P-elements bearing the white minigene were inserted at random into a common genetic background, generating lines of D. melanogaster with single, stable transposon inserts. A series of 48 single-P-element lines revealed statistically significant heterogeneity in both longevity and fecundity. Longevity and early fecundity were only weakly positively correlated (r = 0.286, P = 0.0398). Both the pooled sample and 30 of the individual lines exhibited a leveling of age-specific mortality at advanced ages, in opposition to the classical demographic models. To the extent that these mutational effects are representative of naturally-occurring mutations in heterogeneous populations, this result presents a problem for the evolutionary theory of senescence. Natural selection is inefficient at removing deleterious mutations that are expressed only at late ages, and selection may not differentiate between mutations whose effects on longevity are post-reproductive. A leveling of the mortality rate would also be seen if mutations whose expression is delayed until very late simply do not occur. A simulation of mutation-selection balance among the 48 P-element tagged lines shows that the mean longevity declines monotonically with increasing mutation rate, consistent with the mutation-accumulation model.

Aging↗
PubMed1997

Neuronal responses to vestibular stimulation in the guinea pig hypothalamic paraventricular nucleus.

We investigated the effects of caloric stimulation on neuronal activity in the hypothalamic paraventricular nucleus (PVN) in anesthetized guinea pigs. Hot water stimulation of the contralateral labyrinth produced excitation in 29.4% of the PVN neurons tested, while cold water produced excitation in 22.2% of the neurons. Hot water resulted in inhibition of 22.4% of the neurons and cold water inhibition of 24.7% of the neurons. Intracranial vestibular nerve section greatly reduced responsiveness of the PVN neurons to caloric stimulation, indicating that the majority of the responses observed were vestibular in origin. The response pattern of the individual PVN neurons was similar following hot and cold water stimulation and after stimulation of the contralateral and ipsilateral labyrinths. These results suggest that the PVN neurons receive vestibular afferents bilaterally according to the intensity of vestibular stimulation, with the information received probably integrated in the hypothalamus to participate in vestibulo-autonomic reflexes.

Animals↗
PubMed1991

Unilateral gonadal dysgenesis with both testis and fallopian tube on the same side in a 45,X/46,X inv (Y) mosaic male.

A 5-year-old male with ambiguous external genitalia, hypospadias and microphallus without an urethral orifice was referred for cytogenetic studies. Exploratory laparotomy revealed presence of an infantile uterus and unilateral gonadal dysgenesis with both testes and fallopian tube on the right side. The metaphase cells from peripheral blood culture showed both 45,X/46,X inverted Y (p11.2q11.23) cell-lines (98:2). The inverted Y was found to be of paternal origin. Maternal chromosomal pattern was normal 46,XX. The presence of a fallopian tube next to testis suggest absence of secretion of anti-Mullerian hormone by Sertoli cells. The absence of Wolffian duct derivatives suggest insufficient secretion of testosterone by Leydig cells.

Child, Preschool↗
PubMed1980

Flow cytometric analysis of the DNA content in cultured human brain tumor cells.

Analysis of DNA content in cultured cells derived from 5 benign and 8 malignant human brain tumors was performed by flow cytometry, using propidium iodide as fluorochrome. Normal, non-stimulated human lymphocytes were used as controls. Cells harvested from the first confluent subculture had DNA distribution histograms similar to those of a replicating, non-synchronous population of diploid cells. This observation was made on all cultures, regardless of the DNA distribution patterns in the original tumors, including two metastatic tumors which originally had a predominantly triploid DNA content. After 3 to 5 transfers an increase in the proportion of cells with a wide range of DNA content was observed in some cultures. These changes were usually associated with a loss of cell viability. These observations suggest that in the experimental setting described, in vitro proliferation of human tumor cells may be selectively associated with cells with diploid amounts of DNA.

Adenoma↗
PubMed2002

Mitochondrial DNA variation and RAPD mark oleasters, olive and feral olive from Western and Eastern Mediterranean.

The study of genetic diversity within the olive-tree (cultivated and wild forms) may be useful to reveal agronomic traits in the wild germplasm and to try to understand the history of the olive-tree domestication. In this way, a study of nuclear and mitochondrial DNAs of cultivated and wild olives from two Corsican and Sardinian Mediterranean islands was performed using RAPD and RFLP markers. Our results show that most of the varieties and most of the oleasters were separated using the UPGMA dendrogram based on the Nei and Li similarity index. Most of oleasters carried either the MOM or MCK mitotype, characteristic of olives in the Western Mediterranean, whereas most of the varieties carried the ME1 mitotype, characteristic of olives in the East Mediterranean. The results indicate that the combination of mitotype and RAPD markers can be used as a powerful tool for differentiating two groups in the wild forms: the Western true oleasters and the feral forms. The true oleasters are characterized by a Western mitotype and a Western RAPD pattern. Feral forms originate either from varieties or from hybridisation between a variety and an oleaster. Consequently, as expected, some of them aggregated with the varieties from which they were derived. The other feral forms are clustered with the oleasters and were detected only by their mitotype determination. This study has also permitted us to differentiate two populations of cultivated olives in Corsica: one with close relationships with Italian varieties (influenced by the East) and one selected from local oleasters probably due to a better local adaptation than foreign varieties.

Journal Article↗
PubMed2002

Non-invasive pulsed ultrasound quantification of the resolution of basal cell carcinomas after photodynamic therapy.

The probability of local control of basal cell carcinomas (BCC) treated by photodynamic therapy (PDT) depends strongly on lesion thickness, thicker lesions often requiring two treatments. We examine the utility of 20 MHz pulsed ultrasound (US) for the non-invasive measurement of thickness and rate of regression after PDT treatment. PDT was by topically applied 20% aminolaevulinic acid, followed at 6 h by a standard 100 J/cm(2) of 630 nm light. Patients ( n=60) were selected as being difficult to treat with existing modalities for reasons of likely poor quality of healing or of cosmesis in this very largely elderly population. Ultrasound 'A' scans were made immediately before treatment, and at first and subsequent follow-ups. Parameters measured non-invasively for BCC, adjacent normal skin, and for fibroses after previous conventional therapies, were (a) thickness of skin or lesion, (b) linear density of ultrasound echoes and (c) linear density of high-amplitude echoes. Prior to treatment, median skin thickness (to the dermal/subcutaneous boundary) was 2.6 mm (range 1.2-5.7), fibroses 2.5 mm (1.4-5.6) and BCC 1.5 mm (0.5-4.4). Median linear density of echoes for normal skin, fibroses and BCC plus underlying tissue were 5.6, 5.5 and 4.5, respectively, the BCC values being significantly lower ( p=0.002). The corresponding medians for high-amplitude echoes were 1.9, 1.9 and 1.1 (skin or fibrosis versus BCC, p=0.001). Patients whose BCCs appeared clinically to be controlled at up to 220 days after a single treatment, all had values of ultrasound parameters corresponding to skin/fibrosis and were significantly different from measurements on the same site prior to treatment. Patients whose tumours appeared to be reverting to the original BCC ultrasound pattern were subsequently found to be recurring as judged clinically. Non-invasive pulsed ultrasound indicates that rates of resolution vary widely between BCC of similar initial thickness and that the probability of clearance of BCC by PDT is determined largely by the deepest, sometimes small, regions within a lesion, with the overall area being relatively unimportant.

Adult↗
PubMed2006

Spontaneous basilar-membrane oscillation (SBMO) and coherent reflection.

In a previous report (in JARO) we have described a relatively high-frequency (15 kHz) spontaneous oscillation of the basilar membrane (SBMO) in a guinea pig ear; this oscillation was accompanied by a spontaneous otoacoustic emission (SOAE) at the same frequency. During the spontaneous oscillation and after it had subsided, the mechanical frequency response of the basilar membrane was measured by way of a wide-band random-noise stimulus, and it showed a number of spectral peaks, one of which having the frequency of the original oscillation. This pattern of peaks cannot be explained by assuming a single place of reflection in the cochlea. In this paper the process of 'coherent reflection' is artificially evoked in a three-dimensional model of the cochlea by imposing random place-fixed irregularities to the basilar-membrane impedance. It is shown that in the model a series of peaks arises in the frequency spectrum of the basilar-membrane response which phenomenon resembles the one found in the experimental animal. It is also shown that these peaks are actually due to superposition of the primary wave and a wave resulting from 'coherent reflection' which is reflected at the stapes. When the intensity of the acoustic stimulus signal is increased, the relative sizes of these peaks in the simulation diminish in about the same way as in the experiment. It is concluded that coherent reflection most likely is the cause of the 'extra peaks', and that this concept can also explain the observed level dependence of these peaks. The findings of this study lead to a minor refinement regarding the actual requirements for coherent reflection to arise.

Acoustic Stimulation↗
PubMed1997

A novel culture morphology resulting from applied mechanical strain.

To demonstrate that cells both perceive and respond to external force, a strain/relaxation regimen was applied to normal human fetal and aged dermal fibroblasts cultured as monolayers on flexible membranes. The precisely controlled protocol of stretch (20% elongation of the culture membrane) at 6.67 cycles/min caused a progressive change in the monolayers, such that the original randomly distributed pattern of cells became a symmetric, radial distribution as the cell bodies aligned parallel to the applied force. High cell density interfered with the success of re-alignment in the fetal cell cultures observed, which may reflect a preference in this cell strain for cell-cell over cell-matrix contacts. The chronologically aged cells observed did not demonstrate this feature, aligning efficiently at all seeding densities examined. The role of microfilaments in force perception and transmission was investigated through the addition of cytochalasin D in graded doses. Both intercellular interactions and cytoskeletal integrity mediate the morphological response to mechanical strain.

Actins↗
PubMed1989

Time-locked multiregional retroactivation: a systems-level proposal for the neural substrates of recall and recognition.

This article outlines a theoretical framework for the understanding of the neural basis of memory and consciousness, at systems level. It proposes an architecture constituted by: (1) neuron ensembles located in multiple and separate regions of primary and first-order sensory association cortices ("early cortices") and motor cortices; they contain representations of feature fragments inscribed as patterns of activity originally engaged by perceptuomotor interactions; (2) neuron ensembles located downstream from the former throughout single modality cortices (local convergence zones); they inscribe amodal records of the combinatorial arrangement of feature fragments that occurred synchronously during the experience of entities or events in sector (1); (3) neuron ensembles located downstream from the former throughout higher-order association cortices (non-local convergence zones), which inscribe amodal records of the synchronous combinatorial arrangements of local convergence zones during the experience of entities and events in sector (1); (4) feed-forward and feedback projections interlocking reciprocally the neuron ensembles in (1) with those in (2) according to a many-to-one (feed-forward) and one-to-many (feedback) principle. I propose that (a) recall of entities and events occurs when the neuron ensembles in (1) are activated in time-locked fashion; (b) the synchronous activations are directed from convergence zones in (2) and (3); and (c) the process of reactivation is triggered from firing in convergence zones and mediated by feedback projections. This proposal rejects a single anatomical site for the integration of memory and motor processes and a single store for the meaning of entities of events. Meaning is reached by time-locked multiregional retroactivation of widespread fragment records. Only the latter records can become contents of consciousness.

Animals↗
PubMed1992

A kinematic and strain gauge study of the reciprocal apparatus in the equine hind limb.

Hind limb kinematics were recorded in five horses at walk and trot using an opto-electronic CODA-3 system. Simultaneously, in vivo strain in the completely tendinous peroneus tertius muscle was registered by implanted mercury-in-silastic strain gauges. The origin-insertion length patterns of the peroneus tertius were calculated from raw kinematic data and from data corrected for the error caused by skin displacement, and compared with the directly measured strain. The strain patterns calculated from externally measured kinematic data appeared to be in accordance with the directly measured strain gauge data. However, a correction for skin displacement is an obligatory prerequisite to obtain reliable results. The amplitudes of strain did not exceed 3% and appeared to be of about the same magnitude at both walk and trot.

Animals↗
PubMed1985

The influence of altered working-side occlusal guidance on masticatory muscles and related jaw movement.

The effect of four different occlusal situations (group function, canine guidance, working side occlusal interference, and hyperbalancing occlusal interference) on EMG activity in jaw elevator muscles and related mandibular movement was investigated on 12 subjects. With a computer-based system, EMG and displacement signals were collected simultaneously during specific functional (unilateral chewing) and parafunctional tasks (mandibular gliding movements and various tooth clenching efforts) and analyzed quantitatively. When a naturally acquired group function was temporarily and artificially changed into a dominant canine guidance, a significant general reduction of elevator muscle activity was observed when subjects exerted full isometric tooth-clenching efforts in a lateral mandibular position. The original muscular coordination pattern (relative contraction from muscle to muscle) remained unaltered during this test. With respect to unilateral chewing, no significant alterations in the activity or coordination of the muscles occurred when an artificial canine guidance was introduced. Introduction of a hyperbalancing occlusal contact caused significant alterations in muscle activity and coordination during maximal tooth clenching in a lateral mandibular position. A marked shift of temporal muscle EMG activity toward the side of the interference and unchanged bilateral activity of the two masseter muscles were observed. The results suggest that canine-protected occlusions do not significantly alter muscle activity during mastication but significantly reduce muscle activity during parafunctional clenching. They also suggest that non-working side contacts dramatically alter the distribution of muscle activity during parafunctional clenching, and that this redistribution may affect the nature of reaction forces at the temporomandibular joints.

Adult↗
PubMed1996

Creating phyllotaxis: the stack-and-drag model.

The genesis of phyllotaxis, the origin of the pattern of appendages on the surface just below the apical extreme of many plants, is an old unsolved puzzle. Whereas many models generate helices, the stack-and-drag model is the first to achieve this in an integral construction from seed to flower. Combination of the principle of gnomonic growth, where consecutive additions have comparable positions, with a "dragging" principle, where the developing zone follows the apical tip, provides a powerful tool in simulating a wide range of phyllotactic manifestations. The influence of three vital parameters for primordial size, compressibility, and canalization (or annular arrangement) helps in understanding the problem's nature.

Mathematics↗
PubMed1986

Introduction, rescue and expression of plasmid genes in mammalian cells and Escherichia coli.

A shuttle-vector system is described for the study of mutational specificity in mammalian cells. Using a plasmid (pGKTK) carrying the E. coli galactokinase gene (gk) and the herpes simplex virus thymidine kinase gene (tk), we demonstrate the introduction of a foreign gene into the chromosome of a mammalian cell (TK- mouse fibroblasts) and its efficient rescue back into E. coli. This system makes use of two genes, each of which can expressed in both E. coli and mammalian cells, thereby permitting one marker to be the mutational target and the other to maintain stable integration in the host. In addition, expression of both genes in bacteria makes it possible to deletion map mutants to facilitate their sequencing. In the case of a putative single-copy transformant (T8), about half of the rescued plasmids are identical in size and restriction pattern to the original plasmid. Each of these expressed the tk gene, indicating the fidelity of the rescue system.

Animals↗
PubMed1988

Degeneration and regeneration of the olfactory epithelium following inhalation exposure to methyl bromide: pathology, cell kinetics, and olfactory function.

The effects of acute inhalation exposure to methyl bromide (MeBr) on the olfactory epithelium of male F-344 rats was investigated by morphologic examination of animals killed at varying timepoints during and following exposure to 200 ppm MeBr 6 hr/day for 5 days. Cell replication rate and histopathology were used to assess the kinetics of repair. In addition, olfactory function, using the buried food pellet test, was assessed and the result compared with morphological recovery. Extensive destruction of the olfactory epithelium was evident in animals killed directly after a single 6-hr exposure to MeBr. Histologic features of these lesions indicate that the primary, or most severe, effect of MeBr exposure was on the sustentacular cells and mature sensory cells; basal cells were generally unaffected. By Day 3, despite continued exposure, there was replacement of the olfactory epithelium by a squamous cell layer that increased in thickness and basophilic cytoplasmic staining over the next 2 days of exposure. One week postexposure, the epithelial region was covered by a layer of polyhedral, basophilic cells, and from 2 to 10 weeks postexposure, the epithelium exhibited progressive reorganization to reform the original olfactory epithelium pattern. By Week 10, 75-80% of the olfactory epithelium appeared morphologically normal. Cell replication showed a single peak of olfactory epithelial cell proliferation at Day 3 of exposure, with a labeling index of 14.5% compared to 0.7% in controls. Cell replication rates returned gradually to control levels by Week 10 postexposure. Behavioral tests of olfactory function in animals after a single 6-hr exposure to 200 ppm MeBr demonstrated a loss of the sense of smell, with recovery of this function by Day 6. Exposure to 90 ppm caused no observable effect on olfactory function or morphology. These findings demonstrate that the olfactory mucosa is highly sensitive to the toxic effects of MeBr and that olfactory epithelial cell proliferation, and possible regeneration, begins and occurs rapidly even in the face of continued exposure. Cell replication was most prominent in the layer of basal cells adjacent to the basal lamina, supporting proposals by other workers that the progenitors of both sustentacular cells and neurons reside in this location. Of interest is the fact that functional recovery occurs prior to complete morphological reorganization, indicating the shortcoming of utilizing olfactory morphology as an index of functional integrity.

Administration, Inhalation↗
PubMed1982

Sulfated glycosaminoglycan and collagen patterns in parietal yolk sac carcinoma (PYSC).

Electrophoretic analyses of collagenous material have shown that the parietal yolk sac carcinoma (PYSC) ascitic tumour synthesizes polypeptide chains that migrate as type IV procollagen. Having molecular weights of 185,000 and 160,000, these polypeptides are sensitive to collagenase. When the PYSC cells are injected subcutaneously, they form a solid tumour, and type I collagen predominates. The electrophoretic analyses of sulfated glycosaminoglycans and enzymatic degradation have shown a predominance of heparan sulfate in the ascitic tumour, and of chondroitin sulfate B in the solid tumour. Cells cultured from ascitic tumours have maintained the same collagen and sulfated glycosaminoglycan patterns as the original cells, whereas in the solid tumour culture only chondroitin sulfate AC has been detected.

Animals↗
PubMed1979

Mouse erythropoietic stem cell lines function normally 100 months: loss related to number of transplantations.

Marrow stem cell lines from old and young donors in parallel experiments were transplanted into genetically anemic W/WV recipients. These recipients were populated and their anemias were cured by stem cell lines from WCB6F1 or C57BL/6 dorons that had been repeatedly transplanted up to five times at annual intervals into successive W/WV recipients. Old marrow cell lines produced erythrocytes normally for as long as 2600 to 3000 days. However, after three to four serial transplantations many stem cell lines failed to cure at least two-thirds of the recipients, and all failed by transplantation six. This decline occurred in a similar pattern whether the original stem line donor was old or young. Two experiments suggested that the decline was caused by the transplantation procedure: (1) chromosomally marked donor cells from old and young donors permanently populated lymph nodes in lethally irradiated recipients after the first transplantation, but under the same conditions cell lines from the same donors transplanted a second time were substantially infiltrated by regenerating recipient cells; (2) the ability to compete with the same chromosomally marked cell line in populating irradiated recipients declined markedly in both old and young marrow stem cell lines that had been previoulsy transplanted.

Aging↗
PubMed1992

Cellular protein profiles of the Hodgkin's disease cell lines L428, KM-H2 and HDLM-2: a comparative study.

The origin of the malignant mononuclear Hodgkin's cell and the classic Reed-Sternberg cell in Hodgkin's disease (HD) remains controversial despite extensive immunohistological and lymphoid gene analysis. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in combination with protein staining and radioactive labelling has not been fully exploited in analysing the HD-derived cell lines available. The NP40 solubilised cellular proteins from the three HD cell lines, L428, KM-H2 and HDLM-2 were analysed using these techniques and compared with other haemopoietic cell lines and leucocytes of myeloid and lymphoid origin. The electrophoretic patterns of the three HD cell lines, although clearly different from one another, had many features in common. No major differences between the cell types were detected by Coomassie brilliant blue staining. The HD cell lines were more readily distinguished from the myeloid and to a lesser extent the lymphoid cell lines by silver staining, but HD cell line specific proteins (13, 19, 36, 60, 150 kD) were detected only on one line, L428. Iodination of cell membrane molecules, SDS-PAGE and subsequent autoradiography revealed three molecules (118, 22, 12 kD) which were restricted to the HD cell lines and the B-cell line Mann, and one molecule (144 kD) restricted to the HD cell lines and U937. Molecules unique to HDLM-2 (211 kD) and L428 (46 kD) were also detected by this method. Cell surface labelling with NaB3H4 identified a glycoprotein of 102 kD limited to HDLM-2 and L428, as well as a glycoprotein of 97 kD present on KM-H2 alone and one of 63 kD on L428 alone. Overall the HD cell line protein profiles displayed little similarity to the patterns of the other cell types studied and provide further evidence to support functional and phenotypic studies which identify Hodgkin's cells as a unique cell type. The molecules identified as HD cell line restricted may have potential as markers for this cell type.

Cell Membrane↗