Biomedical subjects
Publications and source records attributed to A Oral.
Intestinal perforation, intussusception, and infarction constitute the major surgical complications in Henoch-Schonlein purpura. Early corticosteroid treatment for intestinal complications is recommended. Here the authors describe the case of a 13-year-old boy with Henoch-Schonlein purpura who had multiple and recurrent perforations that occurred under corticosteroid treatment.
A room temperature scanning Hall probe microscope system utilizing GaAs/AlGaAs and bismuth micro-Hall probes was used for magnetic imaging of ferromagnetic domain structures on the surfaces of crystalline thin film garnets and permanent magnets. The Bi micro-Hall probes had dimensions ranging between 0.25 and 2.8 microm2 and were fabricated using a combination of optical lithography and focused ion beam milling. The use of bismuth was found to overcome surface depletion effects associated with semiconducting micro-Hall probes. Our experiments demonstrated that Bi is a practical choice of material for fabricating sub-micron sized Hall sensors.
Atomic scale dissipation is of great interest in nanomechanics and atomic manipulation. We present dissipation measurements with a linearized, ultra-small amplitude atomic force microscope which is capable of measuring dissipation at chosen, fixed separations. We show that the dynamic dissipation in the noncontact regime is of the order of a few 10-100 meV per cycle. This dissipation is likely due to the motion of a bistable atomic defect in the tip-surface region. In the contact regime we observe dc hysteresis associated with nanoscale plasticity. We find the hysteretic energy loss to be 1 order of magnitude higher for a silicon surface than for copper.
Since the realization that the tips of scanning probe microscopes can interact with atoms at surfaces, there has been much interest in the possibility of building or modifying nanostructures or molecules directly from single atoms. Individual large molecules can be positioned on surfaces, and atoms can be transferred controllably between the sample and probe tip. The most complex structures are produced at cryogenic temperatures by sliding atoms across a surface to chosen sites. But there are problems in manipulating atoms laterally at higher temperatures--atoms that are sufficiently well bound to a surface to be stable at higher temperatures require a stronger tip interaction to be moved. This situation differs significantly from the idealized weakly interacting tips of scanning tunnelling or atomic force microscopes. Here we demonstrate that precise positioning of atoms on a copper surface is possible at room temperature. The triggering mechanism for the atomic motion unexpectedly depends on the tunnelling current density, rather than the electric field or proximity of tip and surface.
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In this study, differences between individuals involved in couple- and family-initiated marriages were investigated with respect to educational background, relationship duration, context and nature of interactions with partner, degree of perceived disclosure, and ratings of different reasons for marriage. Questionnaires were administered to a sample of Turkish men and women who applied for a marriage license for their first marriage. The results revealed differences between individuals involved in the two kinds of marriages, in terms of background variables as well as context of interaction with partner and cognitions concerning the relationship.
BACKGROUND: Chemotherapy-associated thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (C-TTP/HUS) is a condition involving thrombocytopenia, microangiopathic hemolytic anemia, and progressive renal dysfunction that develops in 2-10% of patients with a history of malignant neoplasms treated with certain chemotherapeutic agents. Pathogenesis of the disease may depend on the following: (1) generation of endothelial lesions in the kidney microvasculature, resulting from drug toxic effects and/or generation of small soluble circulating immune complexes (CIC), and (2) generation of autoantibodies and/or CIC that trigger aggregation and deposition of platelets around the lesions. METHODS: Extracorporeal immunoadsorption treatment of plasma (PROSORBA columns, IMRE Corporation, Seattle, WA) to remove immunoglobulin G and CIC was evaluated in 55 patients for the potential to induce significant clinical benefits (increase in platelet count, decrease in hemolysis, stabilization of renal function) and longer survival. RESULTS: Response to therapy was achieved in 25 of 55 patients examined. Response was associated with an estimated 1-year survival rate of 61%, as compared with an estimated survival rate of only 22% in those who did not respond (P = 0.0001). Patients whose malignant neoplasms were in complete or partial remission at the time of development of C-TTP/HUS had a significantly higher estimated 1-year survival rate (74%) as compared with a historic control group of patients receiving other treatments (22%, P = 0.0161). Clinical responses were correlated with normalization of serum levels of CIC and complement components C3c and C4. There were no side effects associated with 75% of treatments. Immunoadsorption therapy was associated with generally mild to moderate manageable side effects, such as fever, chills, nausea/vomiting, respiratory symptoms, pain, hypertension, and hypotension, which were reported in 25% of procedures. CONCLUSIONS: This multicenter study establishes protein A immunoadsorption as an effective and safe treatment for cancer chemotherapy-associated TTP/HUS, an otherwise fatal disease.
We are reporting an unusual case of a 54-year-old woman with polycythemia vera (PV) who developed Ph chromosome positive chronic myelogenous leukemia (CML) 8 years after the initial diagnosis of PV, and terminating in acute lymphoblastic leukemia (ALL), 11 years after the initial diagnosis. Cytogenetic studies revealed a normal female karyotype at the time of diagnosis of PV and the presence of a Ph chromosome at the time of appearance of CML. Southern blot hybridization revealed a bcr rearrangement in both mononuclear cells and granulocytes. The diagnosis of ALL was established on the basis of morphology, positive TdT staining, and monoclonal antibody studies positive for 12, B4, and J5. This case demonstrates the transition of PV into CML, followed by a blastic transformation into acute lymphocytic leukemia. At termination of her disease there were findings compatible with bi-phenotypic leukemia. These findings would suggest that the disease arose in a primitive multipotential stem cell.
The aims of this study were to compare the incidence of hip fracture in different regions of Turkey and to investigate causes for potential differences. Hip fracture cases from two cities (Istanbul and Ankara) and three rural regions (Samsun, Erzurum and Diyarbakir) were compared with non-fractured controls from the same area with similar age and of the same sex. The risk of hip fracture was higher among persons living in rural areas than among persons living in urban areas, RR = 3.2 (p < 0.001) and 2.3 (p = 0.009) in men and women, respectively. Adjustment for differences in age and BMI between cases and controls did not substantially change these findings, RRadj = 2.7 (p < 0.001) and 2.1 (p = 0.036), neither did adjustment for exercise or differences in gonadal status in women. Education was the only adjustment factor that seemed to reduce differences between urban and rural areas, RRadj = 2.0 (p = 0.109) and 1.2 (p = 0.816). No difference in the risk of hip fracture could be detected between persons who migrated from rural to urban areas and persons born in urban areas. When restricting the analyses of differences between rural and urban areas to low-energy fractures, no difference in risk could be detected. When adjusting for differences in age and body mass index (BMI) the relative risks were RRadj = 0.8 (p = 0.873) and 1.2 (p = 0.852). The conclusion of these results is that the observed higher total risk of hip fracture in the rural areas of Turkey primarily can be explained by a larger proportion of high-energy fractures in the rural areas, whereas the risk of low-energy fractures seems to be similar.
The present study, using a sample of Turkish children, aimed to test two attachment-theory predictions: (a) institution-reared children who were separated from their parents at an early age are less likely to have secure attachment schemata than children from two-parent families, and (b) depressive schemata are positively related to insecure attachment schemata and negatively related to secure attachment schemata. Following a systems-theory perspective, we also predicted that the relationship between depression and attachment styles would be stronger for institution-reared children than for children from two-parent families. Hazan and Shaver's (1987) attachment-style items and the Beck Depression Inventory were administered to 20 institution-reared and 20 parent-reared boys by a female interviewer. The results supported the first two predictions of the study.
As a model surface, graphite slides were treated by pure nitrogen gas plasma for different periods (15 sec-5 min). These samples were kept in air or under argon atmosphere in sealed holders. STM images were obtained at constant current mode. Results showed that both the number and the size of clusters formed by plasma deposition increased with exposure time.
The present study attempted to investigate the differences between Turkish late adolescents' relationships with their parents and friends by using Armsden and Greenberg's (1987) scales for measuring attachment. In addition, an attempt at determining predictors of different aspects of attachment was made. The findings were that (a) similar dimensions of attachment emerged from a factor analysis of Turkish data when compared with Armsden and Greenberg's factors, (b) the data provide evidence for the argument that relationships should be studied with an awareness that they exist within a sociological background that includes other relationships, and (c) regression analysis predicting different aspects of attachment indicated that different variables may be important as determinants of men's and women's relationships with significant others.
Three patients treated with intravenous immunoglobulin developed respiratory difficulty and decreased renal function. Previously reported adverse reactions to this class of drugs have included pulmonary toxicity but not, to the best of our knowledge, renal toxicity. Renal dysfunction was mild in one patient but severe in two patients, one of whom required temporary hemodialysis. In all three patients, renal function returned to the pretreatment level after stopping the drug. Urinalysis and urine sodium concentration at the onset of renal failure were consistent with pre renal azotemia although renal biopsy performed later in one patient showed acute tubular necrosis. The exact mechanism of toxicity is unknown, but the fact that all three cases occurred with a particular immunoglobulin preparation would suggest that a contaminant, possibly aggregated IgG might be responsible.
Clinical bleeding tendency and tests of immune function were studied prospectively in 11 human immunodeficiency virus (HIV)-infected hemophiliacs with immune thrombocytopenic purpura (ITP) and a platelet count less than 50,000/microL. These 11 patients represented 13% of a well-characterized cohort of 87 HIV + hemophiliacs. ITP developed a mean 3.5 years after seroconversion, mean platelet count at presentation was 36,000/microL (range 15,000 to 49,000/microL), and the mean age at seroconversion was 37.1 years. Nine patients (82%) suffered bleeding complications, including four with intracranial hemorrhage, which was fatal in three. At the onset of ITP, five had AIDS and six were asymptomatic. Mean T4 lymphocyte count at onset of ITP was 126 +/- 32/microL (range 5 to 267/microL). Sustained treatment responses occurred with intravenous gammaglobulin (2 of 2), one of whom spontaneously remitted, and with zidovudine (1 of 2), but not with steroids (0 of 6) or danazol (0 of 3). In conclusion, 13% of a cohort of HIV + hemophiliacs has developed ITP with platelets less than 50,000/microL, a significant proportion of whom (82%) have experienced bleeding complications. It is recommended that treatment for ITP in HIV + hemophiliacs be instituted once the platelet count falls below 50,000/microL in order to avoid serious hemorrhagic sequelae.
The effect of exercises on vertebral trabecular bone mineral content (BMC) was investigated in 24 women with osteoporosis (OP) diagnosed by Quantitative Computed Tomography (QCT). Two groups were formed: an exercise and a control group with no exercise. Subjects in the exercise group exercised for one hour, twice weekly for a period of 6 months under the supervision of a physical therapist. A home exercise program which included the same exercises used in the hospital plus walking for half an hour every day was also assigned. Initial lumbar X-ray films, values obtained from laboratory investigations, physical activity scores and spinal BMC measurements were compared with those obtained after 6 months. The increase in the level of physical activity in the exercise group after exercise therapy was found statistically significant (p less than 0.001). After the exercise period, BMC values showed a 4.76% increase whereas in the control group, a decrease of 2.7% was found. The results demonstrated the beneficial effect of exercise in the prevention and management of OP.
Idiopathic thrombocytopenia purpura (ITP) is a primary immune thrombocytopenia that is typically manifested in adults by acute bleeding, severe thrombocytopenia, and normal to increased megakaryocytes in the bone marrow. Labeling studies suggest that most patients with ITP have an IgG antibody directed against the platelet membrane resulting in sequestration in the spleen. Splenectomy and/or corticosteroids remain the mainstay of therapy, with permanent remissions induced in 75% of patients. Despite the use of cyclophosphamide, azathioprine, vincristine, high-dose gamma globulin, and other forms of therapy, less than 50% of refractory patients achieve long-term satisfactory platelet counts. In view of these facts, ten consecutive patients with immune thrombocytopenia, unrelated to human immunodeficiency virus (HIV), received plasma perfusion over a staphylococcal protein A column (PROSORBA column) to evaluate efficacy and toxicity. All patients had an initial platelet count less than 50,000 and had failed corticosteroids. Five patients had also failed splenectomy. Two patients were not splenectomized due to pediatric age, two due to severe coexisting medical conditions, and one due to refusal of operation. Multiple other forms of therapy had also failed in this cohort of patients. Patients received two to ten treatments with the protein A column. All patients are evaluable for response and toxicities. Of the ten patients, results were as follows: complete response in one (platelet count greater than 150,000); partial response in four (platelet count greater than 50,000 and less than 150,000); and no response in five. Duration of responses ranged from 1 to 6 or more months.(ABSTRACT TRUNCATED AT 250 WORDS)
Ten patients, with bone marrow failure or malignant disorders, became refractory to platelet transfusions using random, as well as partial or fully HLA-matched, single-donor platelets. To determine its effect on platelet refractoriness, intravenous gamma globulin (IV IgG) was administered at 400 or 800 mg/kg/d for five days, and postinfusion platelet responses were monitored. Platelet transfusion responses following intravenous gamma globulin (IV IgG) were graded as follows: Excellent, 48-hour posttransfusion count greater than 50,000/microL; good, 48-hour count greater than 20,000 but less than 50,000/microL; Fair, increased increment, 48-hour count less than 20,000; and failed, no increased increment. Six of ten patients (60%) had improved responses to selected single-donor platelets (two were excellent, three were good, and one was fair). The time to achieve a platelet transfusion count greater than 25,000/microL ranged from one to nine days of IgG therapy. One individual had sustained benefit (greater than 1 year); the remaining responses persisted for 6 to 8 weeks. These results suggest that IV IgG may be useful in the management of platelet refractoriness, especially in patients receiving single-donor platelets.
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