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PubMed2002

Implant failure with spontaneous rapid exfoliation: case reports.

BACKGROUND: The predictability and success of endosseous dental implants has secured their place as a standard treatment modality. Nevertheless, a small number of implants will fail regardless of operator experience or clinically recognizable cause. This article presents two cases of early failure of two-stage dental implants manifesting in a spontaneous and rapid exfoliation. METHODS: Two healthy adult male patients received single-tooth, machined titanium implant fixtures during uncomplicated stage-one surgical procedures. RESULTS: After an uneventful early postoperative healing phase, both patients returned during the 4 to 6 week time period with failing implants. Clinical examination in both cases revealed the exfoliation of a fixture from the edentulous area with varying signs of soft tissue reaction in each instance. Radiographs revealed osteotomy sites along with the coronally migrating fixtures, with one of the exfoliated implants accompanied by apparent perifixtural radiolucency. In both cases, the implant fixtures were removed digitally without anesthesia. Subsequent medical follow-up was noncontributory, and ultimate healing was uneventful in both cases. Two separate attempts in the mandibular right second premolar region of one patient ended in similar failures despite the successful osseointegration of an identical fixture on the contralateral side. CONCLUSIONS: Few cases of early exfoliation of dental implants have been reported in the literature. Although the exact etiology of the early fixture loss in these two patients is unclear, the description of these cases can add to the published knowledge of dental implant failures and potentially lead to the uncovering and prevention of their causative mechanisms.

Adult↗
PubMed1997

The "clean break" revisited: is U.S. population again deconcentrating?

"The Hoover index, calculated across counties and larger spatial units, is again declining--signalling a renewal of population deconcentration in the United States. After increasing for several decades, the index declined in the 1970s when nonmetropolitan population growth surged past metropolitan-area growth, but the index rose in the 1980s as metropolitan population growth recovered and surpassed nonmetropolitan growth. We update these trends, introducing careful controls for changes in metropolitan-area boundaries, and we incorporate a ¿functional urban region' approach. Although the nonmetropolitan population growth rate is still below the metropolitan rate, we conclude that in the 1990s some features of the ¿turnaround' of the 1970s have returned."

Americas↗
PubMed1981

The role of sialic acid in the functional activity and the hepatic clearance of C1-INH.

The immunochemical properties, catabolic clearance, and organ distribution of highly purified radiolabeled human C1-INH were studied after treatment with glycosidases. The antigenicity and C1s inhibitory activity of C1-INH were unimpaired after removal of sialic acid residues (60%) or sialic acid and galactose residues (60 and 20%, respectively) with immobilized neuraminidase and beta-galactosidase. Treatment of C1-INH with neuraminidase was associated with increased cathodal migration of the glycoprotein. In vivo studies in the rabbit, however, showed that removal of sialic acid residues resulted in rapid blood clearance of C1-INH and enhanced localization of the asialo C1-INH in the liver. Subsequent removal of penultimate galactose residues returned the survival time in the circulation and organ distribution to near normal. Additionally, simultaneous infusion of asialo-C1-INH with asialo alpha 1-acid glycoprotein, a protein known to bind to hepatic asialoglycoprotein receptors, dramatically extended the intravascular survival time of asialo C1-INH. In agreement with the observations on other plasma glycoproteins, these results indicate that desialylation of C1-INH results in rapid clearance by hepatic asialoglycoprotein receptors.

Animals↗
PubMed2005

Growth regulation of the vascular system: an emerging role for adenosine.

The importance of metabolic factors in the regulation of angiogenesis is well understood. An increase in metabolic activity leads to a decrease in tissue oxygenation causing tissues to become hypoxic. The hypoxia initiates a variety of signals that stimulate angiogenesis, and the increase in vascularity that follows promotes oxygen delivery to the tissues. When the tissues receive adequate amounts of oxygen, the intermediate effectors return to normal levels, and angiogenesis ceases. An emerging concept is that adenosine released from hypoxic tissues has an important role in driving the angiogenesis. The following feedback control hypothesis is proposed: AMP is dephosphorylated by ecto-5'-nucleotidase, producing adenosine under hypoxic conditions in the extracellular space adjacent to a parenchymal cell (e.g., cardiomyocyte, skeletal muscle fiber, hepatocyte, etc.). Extracellular adenosine activates A(2) receptors, which stimulates the release of vascular endothelial growth factor (VEGF) from the parenchymal cell. VEGF binds to its receptor (VEGF receptor 2) on endothelial cells, stimulating their proliferation and migration. Adenosine can also stimulate endothelial cell proliferation independently of VEGF, which probably involves modulation of other proangiogenic and antiangiogenic growth factors and perhaps an intracellular mechanism. In addition, hemodynamic factors associated with adenosine-induced vasodilation may have a role in the development and remodeling of the vasculature. Once a new capillary network has been established, and the diffusion/perfusion capabilities of the vasculature are sufficient to supply the parenchymal cells with adequate amounts of oxygen, adenosine and VEGF as well as other proangiogenic and antiangiogenic growth factors return to near-normal levels, thus closing the negative feedback loop. The available data indicate that adenosine might be an essential mediator for up to 50-70% of the hypoxia-induced angiogenesis in some situations; however, additional studies in intact animals will be required to fully understand the quantitative importance of adenosine.

Adenosine↗
PubMed2003

Developmental biology of urodele amphibians in microgravity conditions.

Among the urodele amphibians, only Cynops pyrrhogaster and Pleurodeles waltl, two species of the Salamandridae family, were used in space experiments. The advantages for using urodeles reside (i) in reproduction: a few months after natural breeding, females can lay eggs in absence of males after a hormonal treatment, because spermatozoa were preserved in the cloacal pelvic glands of matted females, (ii) in the rate of development which is slower in Cynops and Pleurodeles than in the anuran Xenopus, (iii) in their physiological properties: they can live in a closed water container or in a moisturized environment, and they can fast during several days. Moreover, urodeles have an important phylogenetic interest. Many biological phenomena differ from those of anurans, such as fertilization events, the germ cell origin and the migration toward the differentiating gonads, and their regeneration capabilities. The main goals of the space experiments were to answer the following questions. On the one hand, does fertilization occur normally in microgravity? Is subsequent embryonic development normal in microgravity? Is further development and reproduction normal after return to Earth? On the other hand, does microgravity affect the organs in adult animals? Does microgravity affect the regeneration of organs? Fertilization in space is clearly demonstrated. However, subsequent embryonic development appears to be altered in microgravity. In Pleurodeles, abnormalities such as cortical cytoplasmic movements, decrease of cell adhesion, and loss of cells were observed. Although, early development was not strictly normal as a consequence of embryological regulation phenomena, young hatching larvae had normal morphological phenotypes and swimming behavior. After landing, no differences were observed between born-in-space animals to standard ones during the embryonic development to adulthood. The analyses of their offspring demonstrated that the percentages of fertilization and development were in accordance with the control animals. No genetic abnormalities were detected during the analysis of the offspring. The development of their progenies were also without characteristic differences compared to control Pleurodeles. Microgravity seems to have effects on the morphological and histological structures of organs of flight adults. However, as was the case in several experiments the number of analyzed adults was low, and it is too early to conclude on specific effects of microgravity. Moreover, in certain flights the temperature was not regulated, and an increase in temperature occurred. Conditions of these space flights had certainly influenced the samples, and consequently the interpretations of results. Space flights have clear effects on organs in regeneration. But more specifically, they have long term effects that last several weeks after the return of the animals to Earth. A similar result was also obtained for otoconia several months after landing. So far, however, no clear hypothesis could be proposed to interpret these observations.

Animals↗
PubMedDate not supplied

Human blood granulocyte macrophage progenitors (GM-CFU) during extended field radiation therapy.

The rate of the clonogenicity of granulocyte macrophage forming cells (GM-CFU) in agar was analysed using mononuclear cells from the peripheral blood of cancer patients undergoing total body irradiation (TBI, 5 patients, 1.5 Gy in 15 days) or hemicorporal irradiation of the lower (LHBI, 5 patients, 15 Gy in 15 days) or upper (UHBI, 4 patients, 15 Gy in 15 days) part of the body. Although the GM-CFU level in the blood is low compared with that in the bone marrow, and shows considerable variability, the preliminary results demonstrated that in most cases the GM-CFU level was increased around the 10th day after the beginning of irradiation, followed by a return to base level within a few days, for LHBI and TBI but not for UHBI. The question of whether the observed peak for the clonogenicity was due to stem cells leaving a radiation-injured compartment of the bone marrow or to vicarious stem cells migrating from non-irradiated regions, or was the result of enhanced activity of colony-stimulating factors, remains to be investigated.

Breast Neoplasms↗
PubMed1991

Endotoxin induces eosinophil accumulation in the rat pleural cavity.

Changes in eosinophil counts after intrathoracic (it) injection of endotoxin (LPS) were investigated in Wistar rats (150-180 g). Increasing doses of endotoxin (62.5-500 ng/cavity) induced a dose-dependent increase in the number of eosinophils recovered from the rat pleural cavity 24 h later. The eosinophilia was apparent within 24 h, peaked within 48 h (from 0.76 +/- 0.12 to 3.68 +/- 0.51 eosinophils x 10(6)/cavity, P less than 0.001) and returned to basal levels 120 h after the it injection of endotoxin (250 ng/cavity). Endotoxin (3 ng-4 micrograms/ml) failed to attract eosinophils in vitro under conditions in which PAF-acether induced a dose-related response. These findings indicate that endotoxin-induced eosinophil migration in vivo is mediated by a secondary mechanism.

Animals↗
PubMed1988

Effect of bacteriophage T4 DNA topoisomerase gene 39 on level of beta chain of ribonucleoside diphosphate reductase in a T4 nrdB mutant.

Bacteriophage T4 ribonucleoside diphosphate reductase consists of alpha 2 and beta 2 subunits encoded by genes nrdA and nrdB, respectively, and plays a central role in the T4-induced deoxyribonucleotide synthetase complex. The accompanying paper describes the decreased rate of synthesis of deoxyribonucleotides after infection by the T4 mutant, nrdB93, and the suppression of this defect by a second mutation in gene 39, coding for one of the three protein chains of T4 DNA topoisomerase. In this study we examined these effects at the protein level. On infection by nrdB93 not only was the beta 93 protein chain altered, as shown by its migration relative to the wild type protein in electrophoretic gels and by its temperature sensitivity, but the infected cells showed very low levels of the protein. However, on infection with the double mutant of nrdB93 and 39-01 (gene 39) the concentration of beta 93 chain returned to the values of beta protein found with wild type phage. A double mutant bearing nrdB93 and an amber mutation of gene 39 also suppressed the nrdB93 defect. By contrast, a temperature-sensitive mutant of gene 39, A41, did not show suppression at either 30 or 41 degrees C. Amber mutations in the two other genes coding for T4 DNA topoisomerase, 52 and 60, did not suppress the defect. We propose that the deficiency in the quantity of beta 93 chain and the suppression of this defect occur at the transcriptional or translational expression of the nrdB93 gene and that a specific domain of the gene 39 protein, not acting in the capacity of T4 DNA topoisomerase, inhibits the expression.

DNA Topoisomerases, Type I↗
PubMed1987

Lymphocyte migration between mutually tolerant parabiotic rats.

Lymphocytes exchanged rapidly and extensively between mutually tolerant, allogeneic rats following surgical parabiosis. Tolerated allogeneic cells persisted for an extended period in parabiotic partners after separation. A rapid exchange of cells was also observed between parabiosed syngeneic pairs of normal and allograft tolerant rats. This was accompanied by early termination of the tolerant state manifested by skin graft rejection and return of specific lymphocyte alloreactivity.

Animals↗
PubMed1977

The influence of prolonged treatment with D-penicillamine on the immune response in Wilson's disease.

Humoral and cell-mediated immunity were studied in a group of patients with Wilson's disease not previously treated with D-penicillamine, and in a group of patients treated with the drug for more than two years. The previously untreated patients showed an exaggerated humoral immune response, i. e. increased levels of IgG and, IgM, higher titer of antibodies to Kunin's antigen, and depression of cell-mediated immunity, namely a decreased response to DNCB, decreased lymphocyte transformation after stimulation with Con A, PPD, Candida and streptokinase and a reduced response to streptokinase in the MIF test. After treatment the humoral response returned to normal, and in the case of IgA and antibodies to S. typhi O antigen, it even dropped below normal values. The cell-mediated immune response returned to normal with the exception of lymphocyte transformation by PHA and Candida albicans. In in vitro studies it was found that D-penicillamine had no influence on lymphocyte transformation when PHA and Con A were used as mitogens. With PPD as antigen, lymphocyte stimulation and migration inhibition were inhibited by concentrations of penicillamine ranging from 6 to 1000 microgram/ml.

Adult↗
PubMed1997

Characterization of an E2F-p130 complex formed during growth arrest.

Electrophoretic mobility shift assays were used to analyse the pattern of E2F transcription factor complexes containing pRB and related 'pocket' proteins associated with changes in growth of monkey CV-1 cells. Little change was noted in pRB/E2F complexes following growth arrest or serum stimulation. Serum starvation induced the formation of a novel slowly-migrating p130/E2F complex, termed C7, which was comparable to one reported previously in terminally differentiated C2C12 mouse cells (Corbeil et al., 1995, Oncogene 11, 909-920) and thought to contain one or more additional unidentified proteins. After serum stimulation, C7 complex disappeared in S-phase but returned during mitosis. A major E2F complex containing p107 appeared during S-phase but was undetectable at other times. It appeared likely that regulation of pRB, p107 and p130 occurs by several mechanisms. First, phosphorylation has previously been proposed to be involved. All pRB-related proteins were found to be highly phosphorylated during S-phase when E2F activity was highest, and hypophosphorylated in arrested cells when E2F activity was low. Second, the absolute levels of some members of the RB family varied during the cell cycle. Levels of pRB protein and pRB/E2F complexes changed little; however, the amounts of both p107/E2F and p130/E2F complexes varied according to the overall levels of p107 and p130 proteins. Formation of the novel C7 complex in serum arrested cells suggested a third regulatory mechanism mediated by interactions with additional proteins. Our studies indicated that binding of such proteins with p130/E2F occurred via a site in the 'pocket' similar to that utilized by adenovirus E1A proteins. Such proteins could function as additional regulators of E2F-driven transcription.

Adenovirus E1A Proteins↗
PubMed1986

Effect of human serum and some of its components on neutrophil adherence and migration across an epithelium.

The effect of human serum and some of its components on the process of transepithelial migration of human neutrophils was investigated in an in vitro system. 10% autologous serum caused an increase in neutrophil adherence to and migration across canine kidney epithelial cells. This increase in neutrophil binding also occurred if the epithelium but not the neutrophils had been preincubated with serum. The binding was lost if the serum was either preabsorbed over the kidney epithelium before use or heat inactivated. Indirect immunofluorescence studies indicated that IgG, IgM, and a component of C3 bound to the epithelial surface, whereas IgA, IgE, or C5a were not detectable. The majority of epithelial cells were immunofluorescent, however epithelial cells with varying degrees of reactivity were also apparent and approximately 5% of the epithelial cells did not bind IgG, IgM, and C3. When epithelia were simultaneously tested for the presence of either IgG, IgM, or C3, and bound neutrophils the few epithelial cells which did not bind IgG or IgM also did not bind C3 or neutrophils. Studies with monoclonal antibodies against Fc and C3 receptors indicate that neutrophil adherence to the epithelial surface was mediated predominately by the receptors for C3b and C3bi. In response to a chemotactic gradient, bound neutrophils were able to detach and migrate across the epithelium. A separate heat-stable factor(s) in serum was able to increase neutrophil migration across the epithelial monolayer. This factor acted independently of the factors which caused the increase in neutrophil binding as the increase in neutrophil migration also occurred under conditions (preabsorption over the kidney epithelium or heat inactivation) that prevented the increase in neutrophil binding. The increase in neutrophil migration may be caused by the permeability-increasing properties of this factor as both serum and heat-inactivated serum lowered the transepithelial electrical resistance an average of 38 and 35%, respectively, in 40 min. Upon removal of serum or heat-inactivated serum, the resistance returned 100 and 81%, respectively, in 5 h.

Animals↗
PubMed1973

Experimental induction of anergy to coccidioidin by antigens of Coccidioides immitis.

Failure to react to coccidioidin (anergy) often occurs in patients with disseminated coccidioidomycosis. One possible reason may be desensitization by excessive amounts of antigen. This was studied experimentally by injection of soluble and hyphal antigens of Coccidioides immitis into coccidioidin- and tuberculin-sensitive guinea pigs. Guinea pigs sensitized by injection of killed hyphal cells of C. immitis in complete Freund adjuvant were subsequently injected daily either with soluble coccidioidal antigen administered intraperitoneally or with hyphal antigen administered either subcutaneously or intraperitoneally. Gradual loss of cutaneous reactivity to coccidioidin occurred, but the reactivity to tuberculin remained unimpaired. The rapidity of desensitization was roughly proportional to the dose of antigen with desensitization occurring as early as 6 days after beginning injections. This anergic state was temporary, and reactivity returned several days after discontinuing injection of antigen. Injection of coccidioidal antigen led to production of coccidioidal complement-fixing antibody, but there was no consistent relationship between the antibody titer and state of cutaneous reactivity to coccidioidin. Peritoneal exudate or pulmonary alveolar cells from desensitized animals migrated freely in the presence of coccidioidin but were inhibited in the presence of tuberculin. Heat treatment did not impair the capacity of the soluble or hyphal antigen to induce anergy, thus suggesting that the antigen active in complement fixation was perhaps not involved in desensitization. Polysaccharide obtained by ethanol precipitation of dialyzed coccidioidin failed to induce anergy. Dialysis of the soluble coccidioidal antigen caused the loss of the desensitizing activity. Thus, specific desensitization could be induced by administration of large doses of coccidioidal antigen but dialyzable components appear important in this desensitization.

Animals↗
PubMed2004

International service trade and its implications for human resources for health: a case study of Thailand.

This study aims at analysing the impact of international service trade on the health care system, particularly in terms of human resources for health (HRH), using Thailand as a case study. Information was gathered through a literature review and interviews of relevant experts, as well as a brainstorming session.It was found that international service trade has greatly affected the Thai health care system and its HRH. From 1965 to 1975 there was massive emigration of physicians from Thailand in response to increasing demand in the United States of America. The country lost about 1,500 physicians, 20% of its total number, during that period.External migration of health professionals occurred without relation to agreements on trade in services. It was also found that free trade in service sectors other than health could seriously affect the health care system and HRH. Free trade in financial services with free flow of low-interest foreign loans, which started in 1993 in Thailand, resulted in the mushrooming of urban private hospitals between 1994 and 1997. This was followed by intensive internal migration of health professionals from rural public to urban private hospitals.After the economic crisis in 1997, with the resulting downturn of the private health sector, reverse brain drain was evident. At the same time, foreign investors started to invest in the bankrupt private hospitals. Since 2001, the return of economic growth and the influx of foreign patients have started another round of internal brain drain.

Journal Article↗
PubMed1976

Recurrent staphylococcal abscesses associated with defective neutrophil chemotaxis and allergic rhinitis.

Four patients with recurrent staphylococcal furonculosis and deep abscess formation were evaluated to determine if a defect in the host defense mechanism could account for the unusual incidence of infection. Each also suffered repeated allergic rhinitis, often preceding the onset of infection. A marked defect in neutrophil granulocyte chemotaxis occurred when the patients were symptomatic with rhinitis and abscess formation. Their mean chemotactic index (+/- SD) was 16 +/- 6, while that of 25 control subjects was 70 +/- 11. Neutrophil random migration, phagocytosis, bactericidal activity, and lymphocyte T-cell populations were normal, as were serum concentrations of IgA, IgG, IgM, and IgE. Serial neutrophil function tests revealed normal chemotactic responsiveness when the patients were symptom-free of allergic rhinitis and no longer having abscesses. Abnormal function returned, however, when symptoms recurred. These studies suggest that defective neutrophil function associated with allergic phenomena need not be accompanied by hyperimmunoglobulinemia E. Such defects may be intermittent, appearing when allergic symptomatology and infections develop.

Abscess↗
PubMed1986

[Liver abscess with pleuropulmonary fistula following hepatobiliary ascariasis in a 18-month-old infant. Apropos of a case with recovery for over 10 years].

This study deals solely with the problem of intra-hepatic collected suppuration due to an ascaris migration through the liver ducts. It is due to the infestation of the intestine germs carried away by the worm but not by the ascaris itself which can die calcified inside the liver without hearing of it, provided no mechanical complication has happened, or if it has returned to the intestine environment. When the illness starts with hepatic colic, a pyrexy with a painful right hypochondria and a painful liver-swelling, if the positive diagnosis, that can have been made from the cutaneous allergy test, the R.A.S.T. [Radioallergosorbent Test]. the sonographic diagnosis, the cholangiography and the C.T. scan, can be proved only by curative aiming surgery, mainly in on-endemic countries. The pre and post-operative anti-helmintics are strongly advised to avoid a reinfestation of the illness.

Antiplatyhelmintic Agents↗
PubMed1981

Mycobacterium fortuitum pulmonary infection associated with an antigen-selective defect in cellular immunity.

In this study we describe the first example of a well documented case of pulmonary infection caused by Mycobacterium fortuitum shown to be associated with an antigen-selective defect in cell-mediated immunity to this organism. Immunologic parameters were evaluated before, during and after antibiotic treatment with amikacin. A defect in cellular immunity to purified protein derivative from Myco. fortuitum, shown to be antigen-selective as indicated by normal responsiveness to purified protein derivative from Mycobacterium tuberculosis and several other common recall antigens, accompanied the prolonged infection by this organism. During the first three months of treatment with amikacin, the patient's clinical status improved coincident with the eradication of the organism from the sputum. During the next three months of therapy with amikacin, however, a generalized defect in cellular immunity developed, and the lung disease again progressed. The deteriorating clinical condition was presumably related to a generalized cellular immune anergy or hyporesponsiveness induced by the amikacin therapy. After three more months of treatment, the organism became resistant to the drug and reappeared in sputum cultures. Since amikacin therapy was discontinued, the patient's general immune responsiveness returned to normal. He did, however, remain unresponsive to purified protein derivative from Mycobacterium fortuitum.

Amikacin↗
PubMed2005

Unstable diaphyseal fractures of both bones of the forearm in children: plate fixation versus intramedullary nailing.

This retrospective study evaluated the results of plating versus intramedullary fixation in the management of unstable, diaphyseal fractures of both bones of the forearm in children. Of the 64 children included, 45 were treated with intramedullary fixation, 19 with plating. Only A3 forearm fractures of the middle third or the transition zones were included; Galeazzi, Monteggia, and Greenstick fractures were excluded. Full radiological follow-up to union was obtained in all cases and 60 patients returned for clinical evaluation 32.3 months (plating) and 20.6 months (intramedullary fixation) after injury. The functional outcome did not differ significantly. In the intramedullary fixation group, we found two major complications (refracture and non-union) and nine minor complications (two delayed unions, three thumb neuropathies, two rod migrations, two skin infections). In the plate group, there were two major complications (refractures) and one minor complication (thumb neuropathy). Plating resulted in significantly worse results for surgical approach, operating times, frequency and duration of hospitalisation, and cosmetic outcome. In conclusion, intramedullary fixation of an unstable forearm fracture in skeletally immature patients is a safe, child-friendly, minimally invasive technique that allows early functional treatment with an excellent functional and cosmetic outcome.

Adolescent↗