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At least 973 records · Page 54Linked to original sources
PubMed1990

Uncemented total hip arthroplasty with superior acetabular deficiency. Femoral head autograft technique and early clinical results.

A technique for primary uncemented total hip arthroplasty in the presence of a superolateral acetabular deficiency is described. The resected femoral head is used as an autograft. Matching reamers are used to ream the pseudoacetabulum and femoral head. Lag screw fixation is then performed and reaming of the graft and host bone simultaneously allows placement of an uncemented acetabular component. The hip center of rotation is returned to its anatomic center, the medial wall and subchondral bone are maintained, maximal contact and rigid fixation is obtained between femoral head autograft and host bone, and press fit of an uncemented cup is achieved. This method was applied to 10 consecutive hips in seven patients who had superior migration of the femoral head. The results were compared to those of 44 uncomplicated primary uncemented total hip arthroplasties during the same time period. While operative time and blood loss were increased in the bone graft cases, the early clinical results were equivalent to those of routine uncemented total hip arthroplasties.

Acetabulum↗
PubMed2001

Covered retrievable tracheobronchial hinged stent: an experimental study in dogs.

PURPOSE: To evaluate the safety and technical feasibility of the use of a covered retrievable tracheobronchial hinged stent and investigate the histopathologic airway changes after placement and removal of the stent in dogs. MATERIALS AND METHODS: The experimental stent was composed of tracheal and bronchial stents that were connected together at their ends. Each stent was woven from a single thread of 0.2-mm-diameter nitinol wire filament in a tubular configuration and covered with polyurethane solution by a dipping method. Drawstrings were attached at the upper end of the tracheal stent for stent removal. Under fluoroscopic guidance, 20 stents were placed at the lower trachea and left main bronchus in 20 dogs and were electively removed 4 weeks (n = 10) or 8 weeks (n = 10) after placement. Ten dogs were killed just after stent removal and the remaining 10 were killed 2 weeks after stent removal. RESULT: Stents were successfully placed in all dogs. Pneumonia was observed in three dogs. Stent migration occurred in seven dogs (35%). Except for two cases of stent expectoration, 18 stents were easily removed within a few minutes. There was considerable granulation tissue proliferation and inflammatory reaction in the airways of the dogs that were killed just after stent removal. The pathologic changes of the airways returned to almost-normal conditions 2 weeks after stent removal. CONCLUSION: Placement and removal of a covered retrievable tracheobronchial hinged stent seems to be feasible, and histopathologic changes of the airway related to the stents returned to normal 2 weeks after stent removal.

Animals↗
PubMed1983

[Analysis of the mortality patterns in an area supplying migratory tunnel workers 1. Regional differences in the mortality patterns].

Tunnel work, digging a tunnel at the face, is a highly specialized job today. Many tunnel workers migrate from one place to another away from home throughout the year. They are exposed to hazardous factors such as dust, vibration, noise and so on, working under the two 12-hour shift system. Recently it has been reported that many workers who had suffered from pneumoconiosis and/or vibration disease returned to their home areas. The southern part of Oita Prefecture is well known as being one of the areas which supply many tunnel workers. In order to study the long-term effects of tunnel work on the health of the tunnel workers, the authors compared the mortality rate in the district supplying many tunnel workers with that of the district supplying few workers. Nine causes of death were chosen among many as indices indicating the characteristics of the structure of mortality in the district supplying many tunnel workers. The authors estimated these causes of death in relation to sex and age, analyzing simple correlations between the 9 causes of death and 33 socioeconomic factors. A principal component analysis of these indices was also carried out. The results were as follows. A close relationship was found between tunnel work and three causes of death such as silicotuberculosis (010), tuberculosis (010-019, A 6), and infective and parasitic diseases (000-136). The other 5 causes of death such as diseases of the digestive system (520-577), neoplasms (014-259), all causes (000-999), stomach cancer (151, A 47) and pneumoconiosis (515) were related not only to tunnel work but also to other regional characteristics such as fishery workers rate. No relationship was found between tunnel work and death by cerebrovascular disease (430-438, A 85). These results show that the tunnel work has an influence on the structure of mortality in the area supplying these workers.

Adult↗
PubMed1999

[Malaria in the Americas].

In 1996, malaria involving Plasmodium vivax, Plasmodium falciparum, and, to a lesser extent, Plasmodium malariae was endemic in 21 countries in the Americas. The Amazon river basin and bordering areas including the Guyanas were the most affected zones. Until the mid 1970s, endemic malaria appeared to be under control. However in the ensuing 15 year period, the situation deteriorated drastically. Although trends varied depending on location, aggregate indexes indicated a twofold increase with recrudescence in previously settled areas and emergence in newly populated zones. Since 1990, the situation has worsened further in some areas where increased incidences have been associated with a high levels of drug-resistant Plasmodium falciparum. However this species remains in minority except in the Guyanas where the highest annual incidences (100 to 500 cases per 1000) and the most drug-resistant Plasmodium have been reported. The causes underlying this deterioration are numerous and complex. In regions naturally prone to transmission of the disease, outbreaks have been intensified by unrestrained settlement. The resulting deforestation has created new breeding areas for Anopheles darlingi, the main vector of malaria in the Americas. Migration of poor populations to newly opened farming and mining areas has created highly exposed areas for malaria infection. Implementation of adequate medical care and prevention measures has been hindered by a lack of money and sociopolitical unrest. Climatic phenomenon related the El Nino have also been favorable to the return of malaria to the region. Except with regard to financial resources and political unrest, the same risk factors for malaria are present in French Guiana.

Animals↗
PubMed2004

[New form of hemorraghic fever in Zaire].

The purpose of this report is to describe the events that occurred immediately before and during the first weeks of the Ebola virus epicemic in the Democratic Republic of the Congo (formerly Zaire) in September and October 1976. By October 4 Dr Raffier and Dr Ruppol were already on hand at the epicenter of the epicemic in the Equator region about 1000 km from Kinshasa. They had been mandated by the State Health Commissioner to conduct a firsthand assessment of the reportedly disastrous local conditions and to implement emergency measures necessary to reassure the population. It was immediately understood to take all steps to prevent mass migration and to collect specimens necessary for rapid identification of the cause of an exceptionally serious crisis situation. Traveling by plane and helicopter the two physicians went to the cities of Bumba and Lissala as well as to many surrounding villages including Yambouku where the first case was reported. Upon returning to Kinshash on October 9, specimens were sent to the CDC in Atlanta where the offending virus was identified. Authorities in Paris and Bruxelles were alerted of the emergency in order to secure the assistance of various specialists incuding virologists, epidemiologists, biologists and entomologists. Most of the new staff arrived on October 23 and were joined by colleagues from the United States, Belgium, and Canada as well as one specialist from South Africa on October 30. These experts were then able to form an International Medical Comission for an in depth assessment of this new epidemic outbreak.

Democratic Republic of the Congo↗
PubMed1991

Transient electric birefringence of two small DNA restriction fragments of the same molecular weight.

The transient electric birefringence of two small DNA restriction fragments of the same molecular weight, one of which migrates anomalously slowly on polyacrylamide gels, has been investigated. Both fragments exhibit negative birefringence. The decay of the birefringence of the anomalously slowly migrating fragment is 8-9% faster than that of the normally migrating fragment. The faster birefringence decay of the anomalous fragment 12A persists under a variety of buffer conditions, suggesting that it is due primarily to static bending and/or curvature of fragment 12A. In reversing electric fields the absolute amplitude of the birefringence of fragments 12A and 12B decreased about 26% before returning to the steady state value. The minimum in the birefringence occurred faster than expected from the birefringence decay times and decreased with increasing electric field strength, suggesting that the minimum is due to a slow polarization of the ion atmosphere. For both fragments, the rise of the birefringence in the Kerr region is about 10% slower than the field-free decay. The buildup of the negative birefringence is preceded either by an interval when no birefringence is observed or by a small positively birefringent transient, suggesting that a small transverse ionic polarizability is also present. Both DNA fragments exhibit Kerr law behavior over most of the range of electric field strengths investigated. Analysis of the shapes of the saturation curves suggests that differences may exist in the polarization mechanisms of the two fragments.

Base Sequence↗
PubMed1988

Dynamic behavior of the transferrin receptor followed in living epidermoid carcinoma (A431) cells with nanovid microscopy.

Transferrin receptors labeled with the B3/25 monoclonal antibody-gold complexes were followed in living A431 cells by using video-enhanced contrast microscopy. Initially, the antibody-gold complexes bind to receptors which are freely mobile on the upper cell surface; they then become trapped at the inner margins of the peripheral lamellae and internalize. During endocytosis discrete gold-loaded vesicular elements first appear, and then, as they fuse, a heterogenous peripheral endosomal compartment forms. The endosomes from this compartment then begin to migrate centripetally through the cytoplasm in a saltatory way so that within 15 min gold label accumulates in a juxtanuclear endosome compartment. This compartment, which consists mainly of multivesicular bodies, is thus formed by the influx and retention of peripheral endosomal elements and their continued fusion in the juxtanuclear area. Although their overall migration is inward, saltating endosomes frequently reverse their direction of movement. As label builds up in the juxtanuclear area, small vesicles containing gold label continuously pinch off from the larger elements and migrate toward the cell periphery. Experiments with nocodazole and sodium azide show that the saltatory movements, the accumulation and retention of endosomes in the juxtanuclear area, and the separation of vesicles from endosomes are driven by a microtubule-associated, ATP-dependent, motility-generating mechanism. Analysis of the movements shows that although each individual vesicle saltation can occur unpredictably toward the centre or the periphery of the cell, a net centripetal flux is observed. Moreover, it is evident that the probability of migration toward and maintenance in the juxtanuclear area is related to the diameter of the vesicles. We propose a mechanism by which bidirectional saltation along microtubules forming a radial network may be instrumental in the selective concentration of large endosomes in the juxtanuclear area while small vesicles are left free to return to the periphery. This process may be responsible for the sorting of receptors and ligands destined either for intracellular degradation in juxtanuclear lysosomes or, alternatively, for recycling to the plasma membrane.

Alkaloids↗
PubMed2006

Demography, immigration background, difficulties with living in Japan, and psychological distress among Japanese Brazilians in Japan.

This study examined the relationship of demography, immigration background, and concerns and difficulties associated with living in Japan to nonpsychotic psychological disturbance (i.e., "caseness") measured by the GHQ-12. Data are from a sample of 265 Japanese Brazilians (JB) residing outside the Tokyo Metropolitan area. Employing multiple logistic regression analyses, it was found that JB who experienced lower economic conditions, lived alone, stayed relatively longer in Japan, migrated to Japan due to their dissatisfaction with the socio-economic conditions in Brazil, and who experienced severe family life concerns had a significantly higher ratio of "caseness," that is psychologically distressed. In contrast, JB over the age of 25 years, who acquired moderate Japanese language proficiency and decided to return to Brazil as soon as possible, were observed to have a significantly lower ratio of psychological distress. Socio-cultural and situational interpretations of the findings are presented.

Acculturation↗
PubMed2000

Reduced inflammatory response in rats fed fat-rich diets: role of leukotrienes.

The effect of fat-rich diets on the acute inflammatory response was examined. Male Wistar rats aged 21 days were fed, for 6 weeks, with a control diet (4% fat content), or a control diet supplemented with coconut or soybean oils (15% fat content). Carrageenan-induced paw oedema and pleurisy were evaluated. Prostaglandin (PG) E2 and leukotriene (LT) C4/D4 concentrations were determined in the pleural exudate (ELISA). Pleural samples were tested for their effect on cutaneous vascular permeability of control rats and the effect of a LTD4 receptor antagonist (L660-711; 10 mg/kg; i.v.) examined. Relative to controls, rats fed both fat-rich diets presented a significant reduction in protein leakage and oedema formation without affecting the number of migrating leukocytes. Production of LTC4/D4 in pleural exudate was significantly increased from 1.8 +/- 0.2 ng/ml in controls to 2.8 +/- 0.2 and 3.0 +/- 0.3 ng/ml in animals fed coconut and soybean oil enriched diets, respectively, without changes in PGE2 production. The activity of these samples on cutaneous vascular permeability was 50% reduced, returning to control values after treatment of testing animals with a LTD4 receptor antagonist. Rats fed fat-rich diets presented a reduced inflammatory response due, at least in part, to the LTC4/D4 mediated vasoconstrictor effect.

Acute-Phase Reaction↗
PubMed2000

Modelling of peripheral lymphocyte migration: system identification approach.

This is the first application of the prediction error method (PEM) of system identification to modelling lymphocyte migration through peripheral lymphoid tissue. The PEM was applied to the emergence of labelled lymphocytes from the efferent lymphatic of a lymph node following their intravenous administration. Advantages of PEM included the capacity to calculate the response to a unit impulse stimulus, unavailable to direct observation, and to allow for the return to the node of labelled cells that had already recirculated once. Calculation of the system delay (time between introduction of cells into the blood and their first appearance in lymph) indicated 4.67 +/- 1.05 h for the total lymphocyte population. The peak in efferent lymph occurred at 11.91 +/- 4.68 h, much earlier than previous reports, which were affected by cells that had already recirculated. While 75% of labelled cells had emerged in efferent lymph by 20.77 +/- 5.62 h, 86.38 +/- 29.44 h was required for 100% emergence. The considerable heterogeneity in migratory behaviour is likely to reflect frequency and duration of binding of lymphocytes by dendritic cells in paracortical cord corridors. It is proposed that differences in the speed with which lymphocytes pass along corridors depend on their functional status, in particular whether they are naïve or memory cells.

Animals↗
PubMed1976

Models allowing for age-dependent survival rates for band-return data.

Seber [1970] and Robson and Youngs [1971] developed a statistical model for a tag-recapture experiment on an exploited animal population in which banded or tagged individuals are released into a population each year, and the bands from harvested individuals are returned by hunters or fishermen in following years. Consideration of certain biological and ecologicw models for an experimental situation where data are recorded separately for birds released as adults and as young-of-the-year. In particular, the effect of different survival rates of young birds, and the effect of migration on reporting rates, are taken into account in the models presented in this study. Maximum likelihood estimators of parameters are derived under the different models, and procedures are developed to discriminate between alternative models as well as provide non-discriminant goodness-of-fit tests.

Age Factors↗
PubMed1998

Autocorrelation function and power spectrum of two-state random processes used in neurite guidance.

During development neurons extend and retract cytoskeletal structures, chiefly microtubules and filopodia, to process informational cues from the extracellular environment and thereby guide growth cone migration toward an appropriate synaptic partner. This cytoskeleton-based exploration is achieved by stochastic switching, with microtubules and filopodia alternating between growing and shortening phases apparently at random. If stabilizing signals are not detected during the growth phase, then the structures switch to a shortening state, from which they can again return to a growth phase, and so forth. A useful means of characterizing these stochastic processes in a model-independent way is by autocorrelation and spectral analysis. Previously, we compared experiment to theory by performing Monte Carlo simulations and computing the autocorrelation function and power spectrum from the simulated dynamics, an approach that is computationally intensive and requires recalculation whenever model parameters are changed. Here we present analytical expressions for the autocorrelation function and power spectrum, which compactly characterize microtubule and filopodial dynamics based on the stochastic, two-state model. The model assumes that the phase times are of variable duration and gamma-distributed, consistent with experimental evidence for microtubules assembled in vitro from purified tubulin. The analytical expressions permit the precise quantitative characterization of changes in microtubule and filopodial searching behavior corresponding to changes in the shape of the gamma distribution.

Animals↗
PubMed1991

Posttraumatic proximal migration of the first metatarsophalangeal joint sesamoids: a report of four cases.

Four cases are presented with plantar plate injury to the first metatarsophalangeal (MTP) joint and proximal retraction of the sesamoids by the flexor hallucis brevis. No history of dislocation occurred in any patient, although two had associated fractures of a sesamoid bone. Clinical and radiographic aids to the diagnosis are discussed. Clinical findings included diffuse pain beneath the first MTP joint and pain with extremes of joint motion in all patients. The anterior-posterior (AP) radiographic technique was the most helpful in determining the proximal migration of the sesamoids. By taking the AP view with both feet on the cassette and by centering the beam perpendicular to it, the diagnosis of plantar plate disruption can easily be made. Initial treatment of this disorder was nonoperative using a stiff soled shoe. With conservative treatment, two of the patients returned to preinjury activities. One patient required sesamoidectomy for resistant pain, and the final patient is still unable to return to his preinjury job requiring standing and heavy lifting.

Adult↗
PubMed1986

The involvement of cellular ATP in receptor-mediated internalization of epidermal growth factor and hormone-induced internalization of beta-adrenergic receptors.

Beta-Adrenergic receptors and epidermal growth factor receptors are both expressed on the cell surface of human astrocytoma cells. Incubation with a catecholamine or epidermal growth factor results in rapid internalization of the respective receptor. The internalized receptors co-migrate in light fractions on sucrose gradients. Astrocytoma cells maintain a constant ATP concentration by either glycolytic or mitochondrial ATP production. When cells are incubated in a medium depleted of substrates for glycolysis and gluconeogenesis, addition of inhibitors of mitochondrial ATP synthesis causes a rapid reduction in cellular ATP content. An immediate return to control ATP levels occurs upon addition of an appropriate nutrient, such as glucose. Decreasing the cellular ATP content to less than 10% of control markedly inhibits internalization of beta-adrenergic receptors and epidermal growth factor. The inhibition of endocytosis is reversed as soon as the intracellular ATP content is restored. Previous work by others (Clarke, B.L., and Weigel, P.H. (1985) J. Biol. Chem. 260, 128-133) suggested that ATP is not required for internalization (per se) of asialoglycoprotein in hepatocytes but was required for recycling of the asialoglycoprotein receptor. In contrast, our results indicate that in astrocytoma cells the process of internalization of epidermal growth factor and beta-adrenergic receptors, per se, is highly ATP dependent.

Adenosine Triphosphate↗
PubMed1984

The effects of starvation and refeeding on intestinal cell proliferation in the mouse.

The effects of starvation and refeeding on intestinal cell proliferation were studied in four sites of the mouse intestine. Control mice were studied at different times of day in order to compensate for any circadian variations in proliferation. A circadian rhythm in crypt cell production rate was observed in all the sites of the small intestine and colon, and this rhythm appeared to be entrained to the food intake. The fractional crypt cell production rate decreased in all sites of the intestine after 24 h starvation, and remained low until 9 h after refeeding, when there was a marked increase in the crypt cell production rate of all the small intestinal sites, especially the proximal sites. There was little change in colonic crypt cell production rate until 12 h after refeeding, when there was a large increase in cell production. The crypt cell production rate of all sites then returned to control values for the remainder of the investigation. Crypt cell number decreased after refeeding and villus cell number increased, however a similar effect was observed in the control animals, nevertheless the changes in villus cell population of the refed mice occurred before any increase in crypt cell production, suggesting that cell migration from crypt to villi is not immediately dependent on cell proliferation.

Animals↗
PubMed1997

Simple detection of in vivo genotoxicity of pyrimethamine in rodents by the modified alkaline single-cell gel electrophoresis assay.

We tested the genotoxicity of pyrimethamine in 5 mouse and rat organs (liver, lung, kidney, spleen, and bone marrow) using a modified alkaline single-cell gel electrophoresis (SCG) (Comet) assay. Mice and rats were sacrificed 1, 3, 6, and 24 h after oral administration of the drug at 50 and 120 mg/kg, respectively. Nuclei were isolated from each tissue and evaluated for DNA migration. Pyrimethamine induced DNA damage in cells of the liver, kidney, and lung in both species. For mice, DNA damage persisted in the liver for 24 h, while it peaked in the lung and kidney at 6 and 24 h, respectively. For rats, DNA damage in the liver peaked at 1 h and returned to almost control level at 24 h. Genotoxicity in the spleen was only observed in mice. Our results suggest that the SCG technique, using isolated nuclei can be applied to rats and mice and that the optimal sampling time is different for different organs and species.

Animals↗