Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
1.
Phys Rev Lett ; 131(2): 021802, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37505961

RESUMO

This Letter reports one of the most precise measurements to date of the antineutrino spectrum from a purely ^{235}U-fueled reactor, made with the final dataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By extracting information from previously unused detector segments, this analysis effectively doubles the statistics of the previous PROSPECT measurement. The reconstructed energy spectrum is unfolded into antineutrino energy and compared with both the Huber-Mueller model and a spectrum from a commercial reactor burning multiple fuel isotopes. A local excess over the model is observed in the 5-7 MeV energy region. Comparison of the PROSPECT results with those from commercial reactors provides new constraints on the origin of this excess, disfavoring at 2.0 and 3.7 standard deviations the hypotheses that antineutrinos from ^{235}U are solely responsible and noncontributors to the excess observed at commercial reactors, respectively.

3.
Niger J Clin Pract ; 22(1): 56-62, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30666021

RESUMO

BACKGROUND/PURPOSE: Gingival biotype (GB) is a crucial factor in predicting the success of soft tissue periodontal and peri-implant surgical interventions. Consequently, contemplating noninvasive, less time-consuming procedure to anticipate it has become a part and parcel of the current practice. This article presents a novel algorithm to detect GB in the Saudi population based on the dentopapillary measurements taken on laboratory models. In addition, it targets to allocate a range of values for thick and thin biotypes. MATERIALS AND METHODS: Model analysis was done on 160 patients to measure eight gingival parameters, and an algorithm was developed according to the results of multiple and linear regression analyses. Applying the dentopapillary parameters to the algorithm revealed a prediction of the biotype. Finally, the resultant values and the exact thickness were reassessed directly in a sample of patients using a modified caliper. RESULTS: The regression analysis revealed an algorithm predicting biotypes among patients based on their measured dentopapillary values. Discriminant analysis was used to allocate the values to thin and thick biotypes to further demystify that they coincide with <0.7 mm and >1.5 mm, respectively. However, gingival thickness between 0.7 and 1.5 mm was considered intermediate biotype. CONCLUSION: GB could be predicted based on the dentopapillary measurements taken on laboratory models, which may further reduce the chairside time and increase the success rate of the surgical procedures. Significant variations in the range of values of the thick and thin biotype were detected in the Saudi population compared to other races. CLINICAL SIGNIFICANCE: The escalating invasion of interventional procedures in the dental practice necessitates measuring the GB as a predictor of procedure success. This study introduces an algorithm for detecting the GB and updates the range of values for thick and thin biotypes in the Saudi population that would consequently reduce chairside time.


Assuntos
Gengiva/anatomia & histologia , Odontometria/métodos , Adulto , Algoritmos , Estudos Transversais , Análise Discriminante , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice Periodontal , Reprodutibilidade dos Testes , Arábia Saudita , Dente
4.
Niger J Clin Pract ; 22(10): 1403-1407, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31607730

RESUMO

BACKGROUND: Empathy and emotional intelligence (EI) of a dentist are two factors vital for developing fruitful relations between clinicians and patients. Establishing a good relationship with patients may improve patients' outcomes. Data on empathy and EI in dental practitioners in the Kingdom of Saudi Arabia is scarce. AIMS: Hence, we aimed to evaluate and compare empathy and EI among dental practitioners in Abha and Khamis Mushayat cities of Saudi Arabia. METHODS: We conducted a cross-sectional survey study. A total of 183 dental practitioners who were reachable at survey time were included. A self-administered questionnaire on empathy and EI was structured based on Jefferson Scale of Physician Empathy (health professions version) and Schutte's Emotional Intelligence Scale, respectively. Statistical analysis was done using Mann-Whitney and Kruskal-Wallis tests. RESULTS: No significant difference was observed between both genders regarding empathy and EI (P = 0.73 and 0.97, respectively). Similarly, no significant difference was observed between participants with different qualifications or different work settings (P > 0.05). However, a statistically significant positive correlation was observed between empathy and EI (r = 0.722). CONCLUSIONS: Irrespective of gender, qualification, or different work settings, dental practitioners in both cities showed adequate empathy and EI levels. Dentists with high empathy scores seem to show high EI levels. CLINICAL SIGNIFICANCE: Evaluating and monitoring empathy and EI practice among dental practitioners have paramount importance to improve clinical practice and healing potential of patients. Low levels of empathy and EI practice would suggest modifications to training curriculum or healthcare policies.


Assuntos
Odontólogos/psicologia , Inteligência Emocional , Empatia , Adulto , Estudos Transversais , Emoções , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Arábia Saudita , Inquéritos e Questionários
5.
J R Army Med Corps ; 162(1): 63-5, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25535320

RESUMO

Prehospital use of blood products may improve survival. However, transfusion support with frozen blood components is logistically burdensome and constrains the configuration of prehospital medical support. Alternatives to frozen plasma, including lyophilised plasma, offer the potential for advanced resuscitation in the prehospital environment. We describe the successful use of lyophilised plasma by a UK patrol in the prehospital environment during operations in Afghanistan in 2012 and reflect on recent military experience and the need for further developments.


Assuntos
Transfusão de Componentes Sanguíneos/métodos , Hemorragia/terapia , Militares , Plasma , Ressuscitação/métodos , Afeganistão , Liofilização , Humanos , Reino Unido , Ferimentos por Arma de Fogo
6.
J Food Sci Technol ; 51(11): 3134-43, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26396305

RESUMO

Indian traditional staple and snack food is typically a heterogeneous recipe that incorporates varieties of vegetables, lentils and other ingredients. Modelling the retorting process of multilayer pouch packed Indian food was achieved using lumped-parameter approach. A unified model is proposed to estimate cold point temperature. Initial process conditions, retort temperature and % solid content were the significantly affecting independent variables. A model was developed using combination of vegetable solids and water, which was then validated using four traditional Indian vegetarian products: Pulav (steamed rice with vegetables), Sambar (south Indian style curry containing mixed vegetables and lentils), Gajar Halawa (carrot based sweet product) and Upama (wheat based snack product). The predicted and experimental values of temperature profile matched with ±10 % error which is a good match considering the food was a multi component system. Thus the model will be useful as a tool to reduce number of trials required to optimize retorting of various Indian traditional vegetarian foods.

7.
Nature ; 450(7169): 497-502, 2007 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-18004281

RESUMO

Derivation of embryonic stem (ES) cells genetically identical to a patient by somatic cell nuclear transfer (SCNT) holds the potential to cure or alleviate the symptoms of many degenerative diseases while circumventing concerns regarding rejection by the host immune system. However, the concept has only been achieved in the mouse, whereas inefficient reprogramming and poor embryonic development characterizes the results obtained in primates. Here, we used a modified SCNT approach to produce rhesus macaque blastocysts from adult skin fibroblasts, and successfully isolated two ES cell lines from these embryos. DNA analysis confirmed that nuclear DNA was identical to donor somatic cells and that mitochondrial DNA originated from oocytes. Both cell lines exhibited normal ES cell morphology, expressed key stem-cell markers, were transcriptionally similar to control ES cells and differentiated into multiple cell types in vitro and in vivo. Our results represent successful nuclear reprogramming of adult somatic cells into pluripotent ES cells and demonstrate proof-of-concept for therapeutic cloning in primates.


Assuntos
Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Macaca mulatta , Técnicas de Transferência Nuclear , Animais , Sequência de Bases , Diferenciação Celular , Células Cultivadas , DNA Mitocondrial/genética , Células-Tronco Embrionárias/imunologia , Feminino , Fibroblastos , Perfilação da Expressão Gênica , Humanos , Macaca mulatta/genética , Macaca mulatta/metabolismo , Masculino , Camundongos , Repetições de Microssatélites/genética , Especificidade de Órgãos , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Transcrição Gênica
8.
J Matern Fetal Neonatal Med ; 35(25): 8327-8330, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34486451

RESUMO

BACKGROUND: Human hemoglobin (Hb) is a tetrameric metalloporphyrin. Heme part contains iron radicle and porphyrin. The globin part has pairs of amino-acid chains. Healthy adults have "Hemoglobin-A" made of two alpha and two beta chains (α2 ß2) while a newborn baby has "Hemoglobin-A (α2 ß2)" and "Hemoglobin-F (α2 γ2)". There are few reports about absorption spectrometry of Hb in cord blood. We have here compared absorption spectrum of Hb in cord blood and maternal blood samples (adult blood samples) together. OBJECTIVE: This was done in two parts. Part 1 was about studying absorption spectrum of Hb in cord blood and maternal blood. Part 2 was about developing a comprehensive noninvasive technology and using the same for measurement of Hb in mother (adult) and new-born baby. DESIGN: Observational study. MATERIAL AND METHODS: Part 1. After IRB approval, 25 pregnant mothers enrolled for the study. Cord blood/neonatal blood samples were collected from placental end in ethylene diamine tetra-acetic acid (EDTA) tube after the delivery of fetus and placenta (venous blood). Maternal blood was collected by peripheral venepuncture before delivery/labor. Part 2. Using noninvasive technology for measurement of Hb in mother (adult) and new-born baby. After the necessary approval five pairs of mother and new-born were enrolled in the study to measure Hb by noninvasive method using our novel device. The novel device (SH-1) uses electromagnetic radiations of specific wavelengths between 520 and 580 nm. Light was projected on forehead for a few seconds, operating the light sources one by one. Of the projected light, some was reflected by the recipient's skin. This optical signal was collected by photosensors and converted to electrical signals. After amplification, this was then transmitted to processor unit. Later, Hbs values are displayed. The results were then tallied with standard laboratory methods in clinical laboratory. RESULTS: Part 1. As expected in our study; all blood samples showed Soret band of same peak and wavelength. We expected different spikes corresponding to four globin chains namely alpha, beta, gamma, and delta. But interestingly, both neonatal and maternal blood samples had identical peaks. Part 2. The results appear promising. The Hb as measured by noninvasive method matches well with standard laboratory test. SIGNIFICANCE: The energy level of Hb is low in deoxygenated state compared to oxyhemoglobin. In a state of high energy level, alpha and beta and gamma globin chains show obvious different peaks. Since cord blood and maternal sample was obviously venous or in deoxygenated state with low energy level, single peak of absorption was observed for all three globin chains. Since maternal and cord blood showed similar absorption spectra, it was possible to develop a common method for estimation of biomarkers - Hb in adults and new-borns alike.


Assuntos
Hemoglobina Fetal , Hemoglobina A , Adulto , Feminino , Humanos , Recém-Nascido , Gravidez , Sangue Fetal/química , Hemoglobina Fetal/análise , Hemoglobina A/análise , Hemoglobinas/análise , Placenta/química , Análise Espectral
9.
Diabetologia ; 54(11): 2867-77, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21800111

RESUMO

AIMS/HYPOTHESIS: A major focus in the treatment of diabetes is to identify factors that stimulate endogenous beta cell growth while preserving function. The first 36 amino acids of parathyroid hormone-related protein (PTHrP) are sufficient to enhance proliferation and function in rodent and human beta cells in vitro. This study examined whether acute and systemic administration of the amino-terminal PTHrP(1-36) peptide can achieve similar effects in rodent beta cells in vivo. METHODS: Adult male mice were injected with 40, 80 or 160 µg of PTHrP(1-36) per kg body weight or with vehicle for 25 days. Glucose and beta cell homeostasis, as well as expression of differentiation markers and cell cycle genes were analysed. RESULTS: All three doses of PTHrP(1-36) significantly enhanced beta cell proliferation in vivo at day 25, with 160 µg/kg PTHrP(1-36) increasing proliferation as early as day 5. Importantly, the two higher doses of PTHrP(1-36) caused a significant 30% expansion of beta cell mass, with a short-term improvement in glucose tolerance. PTHrP(1-36) did not cause hypercalcaemia, or change islet number, beta cell size, beta cell death or expression of differentiation markers. Analysis of islet G1/S cell cycle proteins revealed that chronic overabundance of PTHrP(1-139) in the beta cell significantly increased the cell cycle activator cyclin D2 and decreased levels of cyclin-dependent kinase 4 inhibitor (p16( Ink4a ) [Ink4a also known as Cdkn2a]), but acute treatment with PTHrP(1-36) did not. CONCLUSIONS/INTERPRETATION: Acute and systemic administration of PTHrP(1-36) increases rodent beta cell proliferation and mass without negatively affecting function or survival. These findings highlight the future potential therapeutic effectiveness of this peptide under diabetes-related pathophysiological conditions.


Assuntos
Proliferação de Células/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Proteína Relacionada ao Hormônio Paratireóideo/uso terapêutico , Fragmentos de Peptídeos/uso terapêutico , Via Secretória/efeitos dos fármacos , Animais , Antígenos de Diferenciação/metabolismo , Diferenciação Celular/efeitos dos fármacos , Ciclina D2/genética , Ciclina D2/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Intolerância à Glucose/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/citologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Proteína Relacionada ao Hormônio Paratireóideo/administração & dosagem , Proteína Relacionada ao Hormônio Paratireóideo/efeitos adversos , Proteína Relacionada ao Hormônio Paratireóideo/biossíntese , Proteína Relacionada ao Hormônio Paratireóideo/genética , Proteína Relacionada ao Hormônio Paratireóideo/farmacologia , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/efeitos adversos , Fragmentos de Peptídeos/farmacologia , RNA Mensageiro/metabolismo , Proteínas Recombinantes/biossíntese
10.
Bioresour Technol ; 99(9): 3600-8, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17900893

RESUMO

Biosorption of chromium (VI) was studied using both fresh and spent algal biomass of Spirulina platensis and Chlorella vulgaris. Both showed comparable behavior suggesting that biosorption is primarily a surface phenomenon. Biosorption rate was very fast during the first five minutes, in which almost 50% of the chromium (VI) was adsorbed. Two step kinetic model was proposed for biosorption. Equilibrium data obeyed Freundlich and Langmuir adsorption isotherms. Fresh algal biomass of S. platensis gave maximum of 73.6% biosorption of chromium (VI) in 100 ppm solution at 1 g l(-1) cell loading. For improved economics, beta-carotene was extracted from S. platensis and the spent biomass was used for chromium (VI) biosorption. The maximum biosorption by spent biomass was increased to 86.2%. Thus, this two step process not only showed improved efficiency in biosorption ( approximately 17% increase) but also gave valuable byproduct, namely beta-carotene.


Assuntos
Biomassa , Chlorella vulgaris/metabolismo , Cromo/isolamento & purificação , Modelos Químicos , Spirulina/metabolismo , Adsorção , Biodegradação Ambiental , Meios de Cultura , Concentração de Íons de Hidrogênio , Cinética , Pigmentos Biológicos/isolamento & purificação
11.
Artigo em Inglês | MEDLINE | ID: mdl-18567452

RESUMO

This prospective study evaluated the non-tuberculous mycobacteria (NTM) cases of lymphadenitis. A total of 76 isolates of mycobacteria were obtained from 200 lymph node aspirates suspected of tuberculosis, 74 of which were Mycobacterium tuberculosis, one was Mycobacterium fortuitum and one Mycobacterium kansasii. These results highlight the importance of NTM in HIV-negative patients as a case of lymphadenitis, and indicates the re-emergence of NTM as potential lymph node pathogens in this part of the country. Further studies on a larger scale are needed to delineate the association between NTM infections in HIV positive and negative subjects.


Assuntos
Linfadenite/microbiologia , Mycobacteriaceae/patogenicidade , Adolescente , Adulto , Biópsia por Agulha , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacteriaceae/isolamento & purificação , Estudos Prospectivos , Especificidade da Espécie
12.
Indian J Nephrol ; 27(2): 124-128, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28356664

RESUMO

In clinical practice, serum creatinine-based predicting equations and Gates protocol based on gamma camera imaging of kidneys after injection of Tc99m-diethylenetriaminepentaacetic acid (DTPA) are commonly used to assess glomerular filtration rate (GFR). Comparison of these methods, especially the chronic kidney disease-epidemiology collaboration (CKD-EPI) equation with gold standard method of assessment of GFR by plasma clearance of Tc-99mDTPA is not well-studied in Indian population. We conducted this study to compare GFR estimation by gamma camera-based Gates protocol and serum creatinine-based predicting equations with GFR measured by plasma clearance of Tc-99mDTPA. One hundred and five patients (65 male and 40 female) underwent Tc-99m DTPA renal scan followed by withdrawal of venous blood samples at 2, 3, and 4 h as per predefined protocol. Gates method GFR (GFRs) was assessed using standard protocol. GFR by plasma sampling (GFRp) was calculated by slope-intercept method with provision for corrections. Estimated GFR was calculated by Cockroft-Gault formula, four variable modification of diet in renal disease (MDRD) equation, and CKD-EPI equation (GFRCG, GFRMDRD, GFRCKD-EPI, respectively). GFR measured by gold standard method (GFRp) was compared with that estimated by other methods by calculating correlation coefficient, bias, precision, and accuracy. GFR estimated by all three estimating equations correlated better than GFRs with GFRp. For estimating GFRp, GFRCKD-EPI had highest correlation with GFRp with least bias and highest precision. Gamma camera-based Gates protocol was the least precise and least accurate method for estimating GFRp. To conclude, all three estimating equations based on serum creatinine are superior to Tc-99m DTPA scintigraphy for estimating GFR; CKD-EPI equation being the most accurate and precise.

13.
Int J Tuberc Lung Dis ; 10(4): 447-9, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16602411

RESUMO

SETTINGS: Culture and drug susceptibility testing of Mycobacterium tuberculosis is required for the treatment of drug-resistant tuberculosis. Cetylpyridinium chloride-sodium chloride (CPC-NaCl) solution is recommended for the preservation of sputum during transport. OBJECTIVE: To study the possibility of sputum preservation and transport in CPC-NaCl and its effect on culture. DESIGN: Sputum specimens preserved with CPC-NaCl were transported to the laboratory for culture from remote microscopy centres of Andhra Pradesh and Orissa states, India. RESULTS: Of the 175 specimens, 140 (80%) yielded mycobacteria, 21 (12%) did not yield any growth, 11 (6.2%) grew contaminants and 3 (1.7%) were lost due to leakage. Culture positivity was greater in specimens stored for 1 week. Culture results from specimens stored for 2 weeks are encouraging. CONCLUSION: The CPC-NaCl preservation technique can be used for effective preservation and transport of


Assuntos
Mycobacterium tuberculosis/isolamento & purificação , Manejo de Espécimes/métodos , Escarro/microbiologia , Tuberculose Pulmonar/microbiologia , Meios de Cultura , Humanos , Técnicas In Vitro , Tuberculose Pulmonar/diagnóstico
14.
Lymphology ; 39(2): 69-75, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16910097

RESUMO

Lymphedema is a common clinical problem. Filariasis is the commonest cause of lymphedema in India and is a chronic debilitating disease. The purpose of this study is to highlight the role of lymphoscintigraphy in the evaluation of lymphedema. Our study population consisted of 418 patients diagnosed with filarial lymphedema of different clinical stages referred for lymphoscintigraphy of the limbs by the lymphologist at our institution. An analysis of the various studies was done to determine how lymphoscintigraphy can be useful in documentation of the diagnosis, evaluation, as a screening procedure to prevent progression, and to enhance management of filarial lymphedema.


Assuntos
Filariose/diagnóstico por imagem , Linfedema/diagnóstico por imagem , Adolescente , Adulto , Criança , Diagnóstico Diferencial , Feminino , Filariose/parasitologia , Humanos , Linfedema/parasitologia , Linfografia , Masculino , Pessoa de Meia-Idade , Cintilografia , Enxofre , Tecnécio
15.
Biochim Biophys Acta ; 1030(2): 269-78, 1990 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-2261489

RESUMO

Rhesus monkey erythrocytes were subjected to heating at 50 degrees C for 5-15 min, and the heat-induced effects on the membrane structure were ascertained by analysing the membrane phospholipid organization and membrane skeleton dynamics and interactions in the heated cells. Membrane skeleton dynamics and interactions were determined by measuring the Tris-induced dissociation of the Triton-insoluble membrane skeleton (Triton shells), the spectrin-actin extractability at low ionic strength, spectrin self-association and spectrin binding to normal monkey erythrocyte membrane inside-out vesicles (IOVs). The Tris-induced Triton shell dissociation and spectrin-actin extractability were markedly decreased by the erythrocyte heating. Also, the binding of the heated erythrocyte membrane spectrin-actin with the IOVs was much smaller than that observed with the normal erythrocyte spectrin-actin. Further, the spectrin structure was extensively modified in the heated cells, as compared to the normal erythrocytes. Transbilayer phospholipid organization was ascertained by employing bee venom and pancreatic phospholipases A2, fluorescamine, and Merocyanine 540 as the external membrane probes. The amounts of aminophospholipids hydrolysed by phospholipases A2 or labeled by fluorescamine in intact erythrocytes considerably increased after subjecting them to heating at 50 degrees C for 15 min. Also, the fluorescent dye Merocyanine 540 readily stained the 15-min-heated cells but not the fresh erythrocytes. Unlike these findings, the extent of aminophospholipid hydrolysis in 5-min-heated cells by phospholipases A2 depended on the incubation time. While no change in the membrane phospholipid organization could be detected in 10 min, prolonged incubations led to the increased aminophospholipid hydrolysis. Similarly, fluorescamine failed to detect any change in the transbilayer phospholipid distribution soon after the 5 min heating, but it labeled greater amounts of aminophospholipids in the 5-min-heated cells, as compared to normal cells, after incubating them for 4 h at 37 degrees C. These results have been discussed to analyse the role of membrane skeleton in maintaining the erythrocyte membrane phospholipid asymmetry. It has been concluded that both the ATP-dependent aminophospholipid pump and membrane bilayer-skeleton interactions are required to maintain the transbilayer phospholipid asymmetry in native erythrocyte membrane.


Assuntos
Membrana Eritrocítica/metabolismo , Temperatura Alta , Fosfolipídeos/química , Espectrina/ultraestrutura , Actinas/metabolismo , Animais , Deformação Eritrocítica , Membrana Eritrocítica/ultraestrutura , Fluorescamina/farmacologia , Hidrólise , Macaca mulatta , Microscopia Eletrônica de Varredura , Fosfolipases A/farmacologia , Fosfolipídeos/metabolismo , Pirimidinonas/farmacologia , Radiossensibilizantes/farmacologia , Espectrina/metabolismo , Peçonhas/fisiologia
16.
Biochim Biophys Acta ; 1023(1): 63-72, 1990 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-2317498

RESUMO

Transbilayer phospholipid distribution, membrane skeleton dissociation/association, and spectrin structure have been analysed in human erythrocytes after subjecting them to heating at 50 degrees C for 15 min. The membrane skeleton dissociation/association was determined by measuring the Tris-induced dissociation of Triton-insoluble membrane skeletons (Triton shells), the spectrin-actin extractability under low ionic conditions, and the binding of spectrin-actin with normal erythrocyte membrane inside-out vesicles (IOVs). The spectrin structure was ascertained by measuring the spectrin dimer-to-tetramer ratio as well as the spectrin tryptophan fluorescence. Both the Tris-induced Triton shell dissociation and the spectrin-actin extractability under low ionic conditions were considerably reduced by the heat treatment. Also, the binding of heated erythrocyte spectrin-actin to IOVs was significantly smaller than that observed with the normal cell spectrin-actin. Further, the quantity of spectrin dimers was appreciably increased in heat-treated erythrocytes as compared to the normal cells. This change in the spectrin dimer-to-tetramer ratio was accompanied by marked changes in the spectrin tryptophan fluorescence. In spite of these heat-induced alterations in structure and bilayer interactions of the membrane skeleton, the inside-outside glycerophospholipid distribution remained virtually unaffected in the heat-treated cells, as judged by employing bee venom and pancreatic phospholipase A2, fluorescamine and Merocyanine 540 as the external membrane probes. These results strongly indicate that membrane bilayer-skeleton interaction is not the major factor in determining the transbilayer phospholipid asymmetry in human erythrocyte membrane.


Assuntos
Citoesqueleto/metabolismo , Membrana Eritrocítica/metabolismo , Eritrócitos/metabolismo , Bicamadas Lipídicas/metabolismo , Lipídeos de Membrana/metabolismo , Fosfolipídeos/metabolismo , Actinas/metabolismo , Trifosfato de Adenosina/sangue , Trifosfato de Adenosina/metabolismo , Citoesqueleto/enzimologia , Membrana Eritrocítica/enzimologia , Membrana Eritrocítica/ultraestrutura , Fluorescamina , Glutationa/sangue , Glutationa/metabolismo , Humanos , Hidrólise , Fosfolipases A/metabolismo , Fosfolipases A2 , Fosfolipídeos/sangue , Espectrina/metabolismo
17.
Cardiovasc Res ; 22(4): 296-9, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3058303

RESUMO

Heterotopic cardiac transplantation is a useful method for studying allograft rejection. In this study a new technique of cardiac transplantation was carried out, which involved retroperitoneal anastomoses of the donor ascending aorta and main pulmonary artery with the recipient abdominal aorta and inferior vena cava respectively. The procedure was simple and effective and was accomplished with minimal operative mortality and postoperative morbidity. The method allows better access to the allograft for repeated open myocardial biopsies, obviating the limitations of transvenous fluoroscopically directed endomyocardial biopsy. This technique of retroperitoneal heterotopic cardiac transplantation has important advantages compared with similar procedures performed in the neck, abdomen, or thorax.


Assuntos
Rejeição de Enxerto , Transplante de Coração , Transplante Heterólogo/métodos , Animais , Modelos Animais de Doenças , Suínos , Porco Miniatura
18.
Thromb Haemost ; 86(3): 871-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11583321

RESUMO

Changes in plasma hemostatic and fibrinolytic proteins were determined during courses of a murine model of fatal and non-fatal Rocky Mountain spotted fever. C3H/HeN mice were infected with Rickettsia conorii and coagulation and histopathologic studies were performed at prescribed periods of time. A significant decrease in plasma factor VIII activity and rise in plasma factor V procoagulant activity correlated with a fatal infection. Factor VII levels were unchanged; factor XI levels dropped early in the course in the lethally infected animals, but returned to normal. Factor XII, high molecular weight kininogen, and prekallikrein levels were unchanged by the sublethal infection. Prekallikrein levels fell during the lethal infection. Antithrombin concentrations were decreased significantly in all animals, but plasma plasminogen levels did not change in either group of animals. Nonocclusive thrombi were microscopically observed rarely and only in animals surviving a sublethal infection. A fall in tissue plasminogen activator activity and a rise in plasminogen activator inhibitor activity highly correlated with a lethal outcome. Lethal infection with R. conorii is associated with primary endothelial cell injury resulting in decreased tissue plasminogen activator and increased plasminogen activator inhibitor.


Assuntos
Endotélio Vascular/patologia , Hemostasia , Rickettsia conorii/fisiologia , Febre Maculosa das Montanhas Rochosas/sangue , Animais , Fatores de Coagulação Sanguínea/metabolismo , Embrião de Galinha , Endotélio Vascular/metabolismo , Endotélio Vascular/microbiologia , Fator V/análise , Fibrinólise , Dose Letal Mediana , Camundongos , Camundongos Endogâmicos C3H , Modelos Animais , Tempo de Tromboplastina Parcial , Inibidor 1 de Ativador de Plasminogênio/análise , Tempo de Protrombina , Febre Maculosa das Montanhas Rochosas/complicações , Organismos Livres de Patógenos Específicos , Trombofilia/etiologia , Trombofilia/patologia , Ativador de Plasminogênio Tecidual/análise
19.
Am J Kidney Dis ; 35(2): 319-22, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10676734

RESUMO

Henoch-Schönlein purpura (HSP) is usually a mild condition involving the skin, gut, joints, and kidneys and has a good prognosis. We present a 63-year-old Hispanic man who had an unusually severe form of HSP with a fatal outcome attributable to vasculitis causing myocardial necrosis. There is only one citation in the literature of HSP-related myocardial vasculitis, which involved the right ventricle and was successfully treated with steroids. Our patient had severe HSP-related myocardial necrosis, tracheobronchitis, and nephritis. The bronchial lesions resolved, presumably because of steroid therapy. This probably is the first case of fatal myocardial necrosis related to HSP. We conclude that HSP can, in some cases, have an aggressive course. It becomes imperative to recognize the involvement of the other organ systems, such as the heart, so that appropriate therapy may be initiated. Immunosuppression may have a beneficial effect on extrarenal lesions. Controlled clinical trials are needed to establish the efficacy of such treatment.


Assuntos
Cardiomiopatias/etiologia , Vasculite por IgA/complicações , Vasculite/etiologia , Cardiomiopatias/patologia , Evolução Fatal , Humanos , Masculino , Pessoa de Meia-Idade , Necrose
20.
J Cancer Res Clin Oncol ; 113(2): 151-4, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3455198

RESUMO

(R,S)alpha-[N,N-[bis (2-chloroethyl)]-amino]-N-(o-methoxyphenyl)-pyrrolidin-2,5-dione hydrochloride (I), a new nitrogen mustard incorporated into a 2,5-pyrrolidinedione ring system, was found to be active against P388 lymphocytic leukaemia when administered by i.p., s.c. and p.o. routes. The anti-tumour activity, exhibited by compound (I), against intracerebrally grafted P388 tumour is of interest. However, (R,S)alpha-[N,N-[bis (2-chloroethyl)]-amino]-N-(p-n-butoxyphenyl)-pyrrolidin-2,5-dione dihydrate (II), was found to be active against the P388 tumour following i.p. administration only.


Assuntos
Antineoplásicos/administração & dosagem , Leucemia P388/tratamento farmacológico , Leucemia Experimental/tratamento farmacológico , Compostos de Mostarda Nitrogenada/administração & dosagem , Pirrolidinonas/administração & dosagem , Animais , Antineoplásicos/metabolismo , Barreira Hematoencefálica , Neoplasias Encefálicas/tratamento farmacológico , Ciclofosfamida/administração & dosagem , Camundongos , Compostos de Mostarda Nitrogenada/metabolismo , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA