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1.
Bull Hosp Jt Dis (2013) ; 73 Suppl 1: S111-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26631206

RESUMO

INTRODUCTION: The rate of clinical improvement has never been studied after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty. This study quantifies the rate of improvement after aTSA and rTSA using five different scoring metrics for 1,641 patients. METHODS: We evaluated 1,641 (69 ± 9.3 years old) patients treated by 14 orthopaedic surgeons using either aTSA or rTSA with a single platform shoulder system. Seven hundred twenty-nine patients received aTSA, and 912 patients received rTSA. Each patient was scored preoperatively and at various follow-up intervals (2 weeks, 6 weeks, 3 months, 6 months, annually, etc.) with a maximum follow-up time of 139 months using the SST, UCLA, ASES, Constant, and SPADI metrics. In addition, range of motion was measured. The rate of improvement was analyzed using a 40-point moving filter treadline over the entire range of follow-up. RESULTS: All metrics improved in a majority of patients with less than 5% worsening after 6 months. While gains in motion were present in the majority of patients after aTSA, a higher incidence of patients failed to experience improvement in range of motion after rTSA. Clinical worsening was seen in up to 10% and 20% of the visits for active flexion and abduction and external rotation, respectively. The majority of clinical improvement after aTSA and rTSA was noted in the first 6 months with full improvement noted by 12 to 24 months. During the first 12 months, the rate of improvement associated with rTSA patients was generally 30% larger than that of aTSA patients. DISCUSSION: The results of this large-scale database analysis demonstrate the reliability of improvements in outcomes and motion achieved with both aTSA and rTSA for various indications. For both aTSA and rTSA, less than 5% of patients reported worsening in each of the five clinical metrics after 6 months postoperative follow-up time. This study is significant because it quantifies how patient outcomes improve with time following treatment with both aTSA and rTSA. These results can be used to establish realistic patient expectations regarding the typical follow-up time required for pain to be reduced and function restored following surgical treatment with a total shoulder prosthesis.


Assuntos
Artroplastia de Substituição/métodos , Articulação do Ombro/cirurgia , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Substituição/efeitos adversos , Artroplastia de Substituição/instrumentação , Fenômenos Biomecânicos , Bases de Dados Factuais , Feminino , França , Humanos , Prótese Articular , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Desenho de Prótese , Amplitude de Movimento Articular , Recuperação de Função Fisiológica , Fatores de Risco , Articulação do Ombro/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Estados Unidos
2.
J Eur Acad Dermatol Venereol ; 19(2): 147-52, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15752280

RESUMO

Pityriasis versicolor alba is a hypopigmented or depigmented variant of pityriasis versicolor characterized by maculous, partly pityriasiform, scaly depigmented lesions occurring particularly in seborrhoeic areas. Long-persisting hypopigmentation after healing of the pityriasis versicolor was first described by Gudden in 1853. Hypopigmentation and depigmentation were later differentiated as an independent variant of the disease. In 1848, Eichstedt recognized the pathogen-related character of pityriasis versicolor in its hyperpigmented form. Today it is generally accepted that the disease is caused by yeasts of the genus Malassezia, of which nine species are differentiated. It is controversial whether a single species is responsible for the disease. The pathogenesis of depigmentation has not been established. A screening effect by the scale layer as well as toxic effects on pigment synthesis by fungal metabolites have been discussed. With regard to the second mechanism, the newly discovered tryptophan-derived metabolites of M. furfur might be significant. Evidence-based data concerning the therapy of pityriasis versicolor alba do not exist. According to current recommendations, pityriasis versicolor should be rapidly treated with antimycotics, followed by ultraviolet therapy to induce maturation of existent melanosomes and accelerate repigmentation. However, depigmented lesions are difficult to improve by ultraviolet therapy.


Assuntos
Malassezia , Tinha Versicolor , Antifúngicos/uso terapêutico , História do Século XIX , Humanos , Cetoconazol/uso terapêutico , Microscopia Eletrônica , Pele/ultraestrutura , Pigmentação da Pele , Tinha Versicolor/etiologia , Tinha Versicolor/história , Tinha Versicolor/terapia , Terapia Ultravioleta
3.
Hautarzt ; 55(12): 1137-42, 2004 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-15448927

RESUMO

Localized skin infections caused by the pigmented fungi of the genus Alternaria are being increasingly observed. In the past, primarily patients receiving long-term glucocorticoid therapy were likely to have this mycosis, which is commonly traumatic, but now it is frequently encountered in organ transplantation patients. Possible therapeutic options and differential diagnosis are discussed by means of two case reports--a female renal transplant patient infected by A. alternata and a patient with iatrogenic Cushing syndrome infected by A. infectoria. Histopathological differentiation from other fungal infections may be difficult but is of therapeutic and prognostic significance. Finding short hyphae in tissue sections is an important clue. Since A. infectoria shows little conidial growth in culture, rDNA ITS sequencing offers another diagnostic possibility. Therapy has not yet been standardized. Along with surgical intervention, systemic itraconazole is the usual choice.


Assuntos
Alternaria/isolamento & purificação , Dermatomicoses/diagnóstico , Dermatomicoses/terapia , Itraconazol/uso terapêutico , Idoso , Alternaria/genética , Antifúngicos/uso terapêutico , Dermatomicoses/microbiologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Padrões de Prática Médica , Prognóstico , Resultado do Tratamento
4.
Exp Clin Endocrinol Diabetes ; 112(5): 264-8, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15146373

RESUMO

In diabetic patients, mycotic infections may increase the risk of developing diabetic foot syndrome. However, few data are available on the prevalence of fungal foot infections in patients with diabetes. During a conference attended by patients with long-term diabetes, 95 individuals with type 1 diabetes mellitus (52 men, 43 women, mean disease duration 35.8 years) were examined for fungal infections of the feet. As well as frequency of infection and risk profiles, the level of patient awareness and preventive measures taken were assessed by means of a questionnaire. Clinically, 78 patients (82.1 %) showed probable pedal fungal infections, of which 84.6 % (66/78) were mycologically confirmed by direct microscopy and/or culture. Skin mycoses were found in 9 patients (toe webs 5, soles 4), onychomycosis in 29 patients and simultaneous infection of nails and skin in 28 patients (toe webs 8, soles 20). Thirty-seven (47.4 %) of these patients had positive cultures, particularly for the dermatophyte Trichophyton rubrum (69.2 % of isolates). A significant correlation was found between infection and gender (men more frequently affected) and the age of the patients. The actual frequency of mycoses was underestimated by the patients. This correlated with the assessment of their own knowledge level concerning fungal infections: 83.2 % of patients with skin mycoses and 88.4 % of those with onychomycosis of the feet felt that they needed more information about their disease. Marked mycoses on the soles were often considered to be dry skin by the patients. The high number of infections detected is especially remarkable in that this group of patients were highly motivated. It therefore appears that diabetics require more diagnostic, therapeutic and preventive care in terms of mycotic diseases than has been previously thought.


Assuntos
Dermatomicoses/epidemiologia , Diabetes Mellitus Tipo 1/microbiologia , Pé Diabético/microbiologia , Micoses/epidemiologia , Tinha/epidemiologia , Feminino , Humanos , Masculino , Onicomicose/epidemiologia , Prevalência , Reprodutibilidade dos Testes , Inquéritos e Questionários
5.
Bioorg Med Chem ; 9(4): 955-60, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11354679

RESUMO

The yeast Malassezia furfur converts tryptophan into several indole compounds. One of these, malassezin, was identified as 2-(1H-indol-3-ylmethyl)-1H-indole-3-carbaldehyde (1). It was synthesized from N-Boc-indole-3-carbaldehyde in five steps with 12% overall yield. The compound easily cyclizes to indolo[3,2-b]carbazole (7) which is known to interact with the arylhydrocarbon receptor (AHR). Similarly, malassezin was found to induce cytochrome P450 as an agonist of AHR (EC50 = 1.57 microM) in rat hepatocytes.


Assuntos
Indóis/farmacologia , Malassezia/química , Receptores de Hidrocarboneto Arílico/agonistas , Animais , Cromatografia em Camada Fina , Citocromo P-450 CYP1A1/antagonistas & inibidores , Citocromo P-450 CYP1A1/metabolismo , Inibidores Enzimáticos/farmacologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Indicadores e Reagentes , Indóis/isolamento & purificação , Masculino , Modelos Moleculares , Monofenol Mono-Oxigenase/antagonistas & inibidores , Ratos , Ratos Wistar
6.
Orthopade ; 29(7): 614-26, 2000 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-10986706

RESUMO

Modern approaches in knee endoprosthetics using computer-assisted navigation systems are based on matching procedures which refer to osseous anatomical landmarks. However, surface replacement techniques require a correct position of the implants in relation to the bone, as well as an optimal postoperative interaction of the ligaments and the surface design of the endoprosthesis. Functional aspects are of elementary importance. Insufficient design of the prosthetic surface or incorrect implantation overstresses ligamentous structures and result in functional disturbance, increased wear, and early loosening of the components. The present computer model permits a quantitative analysis of different implant positions. Distal positioning of the femoral component or insufficient resection of the tibial plateau results in a lag of extension. Increased distal resection of the tibial plateau produces marked translatory instabilities in the sagital plane which exceed the absolute height of the resection in millimeters. Monocondylar replacements with preservation of the ACL react kinematically more sensitively than bicondylar endoprostheses sacrificing the ACL. The results of this study are systematically summarized in an algorithm and indicate correction steps in order to avoid functional impairment. The computer model delivers in addition some basic data for optimized navigation procedures in knee surgery and demonstrates the importance of further developments in custom-made endoprosthetics.


Assuntos
Artroplastia do Joelho , Processamento de Imagem Assistida por Computador , Prótese do Joelho , Terapia Assistida por Computador , Algoritmos , Fenômenos Biomecânicos , Humanos , Instabilidade Articular/etiologia , Falha de Prótese , Tíbia/cirurgia
7.
Orthopade ; 29(7): 641-4, 2000 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-10986709

RESUMO

A new method is presented which allows the construction and implantation of highly precise custom-made endoprostheses for knee joints. The procedure is based on a computer-aided subtraction process of three-dimensional CT data. Using the differences of the CT scans, the endprosthetic components are modelled by means of a newly developed software package. The implants are manufactured by CNC machines and stereolithography. The method enables the surgeon to reduce bone resections and ensures an exact profile of the bone-implant interface. Incorrect positioning will be avoided and the implantation process can be performed more easily while the size of the operative approach will be minimized. Better postoperative kinematics and reduction of shearing effects will lead to better results in the long run. The procedure offers a series of new possibilities to optimize monocondylar and bicondylar knee joint endoprostheses.


Assuntos
Artroplastia do Joelho , Processamento de Imagem Assistida por Computador , Prótese do Joelho , Técnica de Subtração , Terapia Assistida por Computador , Tomografia Computadorizada por Raios X , Fenômenos Biomecânicos , Humanos , Período Pós-Operatório
8.
Orthopade ; 28(3): 227-35, 1999 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-10326205

RESUMO

During the last years physicians are confronted with a significant increase of their duties in clinical documentation. By law the medical diagnoses and procedures were linked with the aspect of liquidation. In consequence it is very important that physicians work out a detailed list of options concerning the features of the medical database, which has to cover the complete clinical data input and deliver flexible utilities for detailed evaluation. Beside documentation the system has to perform as an essential tool of clinical organisation and quality control to optimize the medical and commercial efficiency of the hospital. An open interface technology should be postulated to avoid a stand alone system in the long run.


Assuntos
Bases de Dados como Assunto , Documentação , Sistemas Computadorizados de Registros Médicos , Ortopedia , Processamento Eletrônico de Dados , Registros Hospitalares , Humanos , Sistemas de Informação
9.
Orthopade ; 28(3): 227-235, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28246940

RESUMO

During the last years physicians are confrontated with a significant increase of their duties in clinical documentation. By law the medical diagnoses and procedures were linked with the aspect of liquidation. In consequence it is very important that physicians work out a detailled list of options concernig the features of the medical database, which has to cover the complete clinical data input and deliver flexible utilities for detailed evaluation. Beside documentation the system has to perform as an essential tool of clinical organisation and quality control to optimize the medical and commercial efficiency of the hospital. An open interface technology should be postulated to avoid a stand alone system in the long run.

10.
Mycoses ; 41(7-8): 265-71, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9861829

RESUMO

A new minimal medium consisting only of L-tryptophan (L-Trp) and a lipid source induced formation of brown pigmentation only in the species Malassezia furfur, which diffuses into the agar. Strains of the species M. sympodialis and M. pachydermatis failed to grow on this medium. On mDixon medium, however, after replacement of peptone by L-Trp, growth of all three Malassezia species was achieved. Under these conditions pigment production was observed with all M. furfur strains tested, although the results for M. pachydermatis strains were inconsistent. M. sympodialis strains showed no pigment production. On the minimal medium pigmentogenesis was induced in M. furfur by only 0.01 g% tryptophan; the pH optimum was pH 5. In all M. furfur strains, alternative amino nitrogen sources given concurrently with Trp suppressed pigmentogenesis. Furthermore, there were differences in the optimal temperature among the individual M. furfur strains. CBS 7019, CBS 6000 and CBS 6001 failed to produce pigment at 37 degrees C. The extract of the culture exhibited remarkable fluorescence, and several indole derivatives with a broad spectrum of colours were detected. This finding may have an impact on the clinical appearance of pityriasis versicolor, a very common skin disease caused by lipophilic yeasts of the genus Malassezia. We hypothesize that in pityriasis versicolor metabolic adaptation of Malassezia yeasts to altered nitrogen conditions on superficial skin might be of patho-physiological importance. Tryptophan as an inducer of pigmentogenesis probably accumulates during excessive sweating, a well-known manifestation of pityriasis versicolor.


Assuntos
Corantes Fluorescentes/metabolismo , Malassezia/metabolismo , Pigmentos Biológicos/metabolismo , Triptofano/metabolismo , Humanos , Malassezia/crescimento & desenvolvimento , Malassezia/isolamento & purificação , Tinha Versicolor/microbiologia
11.
Z Orthop Ihre Grenzgeb ; 136(5): 420-7, 1998.
Artigo em Alemão | MEDLINE | ID: mdl-9823637

RESUMO

AIM OF THE STUDY: Several CT-procedures exist to determine rotational variances of the femur. However, solely on the basis of few CT-scans and without a three-dimensional reconstruction of the femur, it is impossible to define the exact course of the femoral neck axis. Looking for determination of the exact course of the femoral neck axis, auxiliary constructions need to be called upon. Aim of the study was to validate several existing CT-procedures and analyse their respective error rates. METHOD: Fourty-five femora were CT-scanned and subsequently reconstructed three-dimensionally in this study. Femoral anteversion was measured using three different CT-methods in each of these femora and in addition, the respective anatomical anteversion was determined in each femur. In order to test the reliability of such methods, flexion of the femora around the center of the femoral head as well as a varus deformity of the longitudinal axis of the femora were simulated and anteversion measurements were repeated in such simulated positions. Results were statistically analysed using SPSS. RESULT: All tested CT-methods, when compared to the anatomical anteversion of a femur, showed differing anteversion-angles with statistical significance (p < 0.001). Equally, the results of the individual methods tested differed with significance. Due to a high correlation with the anatomical anteversion, all methods examined expressed trend of anteversion. Under simulated hip flexion, the "Ulmer Method" produced different values with statistical significance which were, however, without correlation to anteversion values in joint extension. With statistical significance, the "Essener Method" produced different anteversion values when the longitudinal axis of the femur was modified; however, these values highly correlated to anteversion values of femora with unchanged longitudinal axis. CONCLUSION: Our results lead us to conclude that the "Essener Method" being an interindividual method and independent from positioning, is the most suitable procedure as it allows for the correction of errors with respect to anatomical anteversion.


Assuntos
Fêmur/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X , Cabeça do Fêmur/diagnóstico por imagem , Colo do Fêmur/diagnóstico por imagem , Humanos , Amplitude de Movimento Articular/fisiologia , Valores de Referência , Sensibilidade e Especificidade , Anormalidade Torcional
12.
Mycoses ; 41 Suppl 2: 74-7, 1998.
Artigo em Alemão | MEDLINE | ID: mdl-10085692

RESUMO

A new minimal medium consisting only of L-tryptophan (L-trp) and a lipid source induced formation of brown pigmentation only in the species Malassezia furfur. Strains of the species M. sympodialis and M. pachydermatis failed to grow on this medium. Pigmentogenesis was already induced in M. furfur by 0.01 g% tryptophan, the pH optimum was pH = 5. Alternative amino nitrogen sources given concurrently with trp suppressed pigmentogenesis. The extract of the culture exhibited remarkable fluorescence, and several indole derivatives with a broad spectrum of colors were detected by means of mass spectroscopy and NMR. This finding may have an impact on the clinical appearance of pityriasis versicolor, a very common skin disease caused by lipophilic yeasts of the genus Malassezia. We hypothesize that in pityriasis versicolor metabolic adaptation of Malassezia yeasts to altered nitrogen conditions on superficial skin might be of pathophysiological importance. Tryptophan as inductor of pigmentogenesis probably cumulates during excessive sweating, a well known manifestation factor of pityriasis versicolor.


Assuntos
Malassezia/metabolismo , Triptofano/metabolismo , Dermatomicoses/microbiologia , Humanos , Malassezia/crescimento & desenvolvimento
13.
Z Orthop Ihre Grenzgeb ; 131(1): 14-7, 1993.
Artigo em Alemão | MEDLINE | ID: mdl-8480433

RESUMO

Usually the upper ankle joint is described as a typical hinge though it had been often remarked that the axis of rotation moves considerably with regard to the angular adjustment between the tibia and the trochlea tali. In the present study the relation between the movements in the upper ankle joint and the geometry of the lateral ligaments was analysed. The contours and elected landmarks of 6 dissected ankle joints were measured using a digitizer which allowed the computerized scanning of motion x-rays. In addition the proximal and distal insertion planes of the lateral ligaments were registered. Mathematical procedures were applied on the experimental data to predict the kinematic principles. The model of an hinged joint could not reproduce the motion curve which was actually found. Using the model of a link chain with four pivots, which was determined by the course of the talofibular and the calcaneofibular ligament, a good correlation with the experimental results was evident. This model implies a rotary and gliding component in the movement of the tibia against the trochlea tali. Beside the correspondence with the data of the present study the model allows an easy explanation of many other well known morphologic phenomena of the upper ankle joint for which a stringent interpretation was not yet available.


Assuntos
Articulação do Tornozelo/fisiologia , Movimento , Interpretação de Imagem Radiográfica Assistida por Computador , Fenômenos Biomecânicos , Humanos
14.
Z Orthop Ihre Grenzgeb ; 130(5): 364-6, 1992.
Artigo em Alemão | MEDLINE | ID: mdl-1462693

RESUMO

The procedures of documentation of diagnostic findings are well established--but different in their graphical and structural appearance of patients histories. Out of multiple findings a retrieval with valid informations is very clumsy. In order to increase quality a complete and reliable registration of clinical data base is necessary. For this purpose the use of electronic media is profitable if the requirements of the data-base are well defined. A nationwide agreement on one key-system--including the transformation of textual structures--is proposed. Only this way leads to comparable results in therapeutic procedures.


Assuntos
Diagnóstico , Documentação/métodos , Sistemas de Informação Hospitalar , Computação em Informática Médica , Sistemas Computadorizados de Registros Médicos , Garantia da Qualidade dos Cuidados de Saúde , Terapêutica , Coleta de Dados , Interpretação Estatística de Dados , Doença/classificação , Humanos , Software
15.
Circ Res ; 70(6): 1137-45, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1576734

RESUMO

Difficulties in studying myocardial metabolism with adequate time resolution have led to contradictory conclusions regarding the mechanisms causing contractile abnormalities during the early stages of ischemia. In acutely instrumented swine, we investigated whether abnormalities in subendocardial ATP, phosphocreatine, or lactate content develop rapidly enough during the first few heart beats after onset of partial myocardial ischemia to contribute to contractile failure. Within the first 15 beats of a 40-50% reduction in left anterior descending coronary artery blood flow, regional myocardial function was significantly reduced but continuing to deteriorate. Rapidly frozen transmural left ventricular biopsies obtained on the 15th heart beat (+/- 1.5 beats) after the onset of ischemia revealed significant decrements in subendocardial phosphocreatine and ATP levels to 77% (p less than 0.05) and 84% (p less than 0.005) of control values, respectively, but minimal change in lactate content. Metabolic effects as assessed by transmural averages took longer to become detectable; thus, there was a tendency to underestimate the importance of subendocardial metabolic effects on myocardial function. When left ventricular preload was assessed during this early time period, left ventricular end-diastolic wall thickness only decreased by 3%, and left ventricular end-diastolic pressure did not change significantly despite a large fall in coronary perfusion pressure. Thus, in an in vivo pig model with techniques optimized to detect subendocardial metabolic changes within the period of very early moderate myocardial ischemia, abnormalities in high energy phosphate compounds occurred rapidly enough to contribute to developing myocardial dysfunction, whereas preload-mediated mechanisms related to vascular distending pressure could not explain the functional deterioration under these conditions.


Assuntos
Doença das Coronárias/fisiopatologia , Contração Miocárdica , Miocárdio/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Doença das Coronárias/metabolismo , Eletrocardiografia , Metabolismo Energético , Feminino , Hemodinâmica , Lactatos/metabolismo , Masculino , Fosfocreatina/metabolismo , Suínos , Fatores de Tempo
17.
Sportverletz Sportschaden ; 6(1): 6-13, 1992 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-1585254

RESUMO

Following anterior cruciate ligament replacement plasty performed via arthroscopy, isokinetic and isometric power data were measured at the beginning and end of a sports therapy treatment course. Evaluation yielded surprising results that were partly contradictory to those communicated in current literature. Besides the dependence of force values on preset velocities of motion in dynamic measurements (isokinetics) or in static measurements (isometrics), markedly lower losses of power than expected were measured in the involved extremity on repeated power application. Possible reasons are discussed on the basis of specific innervation criteria and polymodal reflexes. We assume that muscle potential is not yet fully available after surgical intervention, due to reflexive modulations of power realisation, so that the joint and especially the anterior cruciate ligament are thus protected from damage.


Assuntos
Lesões do Ligamento Cruzado Anterior , Artroscopia , Traumatismos em Atletas/cirurgia , Contração Isométrica/fisiologia , Traumatismos do Joelho/cirurgia , Complicações Pós-Operatórias/fisiopatologia , Amplitude de Movimento Articular/fisiologia , Adulto , Ligamento Cruzado Anterior/fisiopatologia , Ligamento Cruzado Anterior/cirurgia , Traumatismos em Atletas/fisiopatologia , Teste de Esforço , Seguimentos , Humanos , Traumatismos do Joelho/fisiopatologia
18.
Biochemistry ; 29(15): 3731-43, 1990 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-2340268

RESUMO

The mechanisms that underlie the balance between the consumption and oxidative generation of ATP in the intact cell are not well-defined. Cytosolic inorganic phosphate (Pi) and ADP levels, the cytosolic ATP/ADP ratio, and the cytosolic phosphorylation potential (PP) have all been proposed as major regulatory variables, the latter as a component of a "near-equilibrium" thermodynamic regulatory scheme. Therefore, the potential regulatory roles of these variables in the intact cell were evaluated with 31P NMR and Langendorff perfused rat hearts; in this preparation, the tissue oxygen consumption rate (MVO2) can be varied over a wide range. When the exogenous carbon source was varied, none of the proposed regulatory parameters, i.e., the ATP/ADP ratio, PP, or cytosolic ADP level, were found to be uniquely related to MVO2. Rather, ADP levels at a given MVO2 decreased progressively for the exogenous carbon sources in the following order: glucose, glucose + insulin, palmitate + glucose, lactate, pyruvate + glucose, and octanoate + glucose. In the octanoate and pyruvate groups, MVO2(-1) was linearly dependent upon [ADP]-1 with apparent Km values being in the range previously observed in isolated mitochondria. A similar trend was observed in the MVO2-[Pi] relationship. The present findings suggest that exogenous carbon sources which effectuate deregulation of intramitochondrial NADH generation lower cytosolic ADP and Pi to levels which are limiting to the rate of oxidative phosphorylation. For other carbon sources, the processes controlling the rate of NADH generation also participate in determining the rate of oxidative ATP synthesis. However, this control must be exerted kinetically rather than through a near-equilibrium thermodynamic mechanism as indicated by the present data and prior kinetic studies of the ATP synthetic process in both isolated mitochondria and intact myocardium [La Noue, K. F., et al. (1986) Biochemistry 25, 7667-7675; Kingsley-Hickman, P., et al. (1987) Biochemistry 26, 7501-7510].


Assuntos
Miocárdio/metabolismo , Fosforilação Oxidativa , Trifosfato de Adenosina/metabolismo , Animais , Ácido Dicloroacético/farmacologia , Ativação Enzimática , Técnicas In Vitro , Cinética , Metabolismo dos Lipídeos , Espectroscopia de Ressonância Magnética , Oxirredução , Consumo de Oxigênio , Perfusão , Complexo Piruvato Desidrogenase/metabolismo , Ratos , Ratos Endogâmicos
19.
NMR Biomed ; 2(5-6): 298-304, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2641903

RESUMO

A procedure for obtaining T1 values for phosphorous metabolites in localized regions of human subjects, using a standard 1.5 T MR imager, is described. 31P spectra and T1 values localized to the liver, and to abdominal and calf muscle of healthy volunteers were obtained by means of a multi-slice spectroscopy technique, consisting of a chemical shift imaging (CSI) sequence with a B1-insensitive excitation and one dimension of phase encoding, used in conjunction with a surface coil. An examination consisting of proton imaging, shimming and collection of 31P progressive saturation spectroscopic data for T1 determination required 1 h to perform. Shimming on the signal from the body region detected by the surface coil gave spectra of excellent spectral resolution. Quantification of all peaks in the localized 31P spectra was carried out with the PIQABLE algorithm, and T1 values were calculated for inorganic phosphate (Pi), the phosphodiester region, and the ATP alpha-, beta- and gamma peaks of liver, and for calf muscle Pi, phosphocreatine (PCr), and the three ATP peaks. The precisions of the measurement and of the entire process for obtaining and quantifying localized spectra by one-dimensional CSI were determined, and the accuracy of T1 values obtained by this means was verified. The temporal variation in T1 values obtained in a series of examinations of a single normal subject was also assessed. The consistency of the T1 values obtained in this study with in vivo T1 values obtained by other techniques is a stringent test of accuracy of localized spectra obtained with CSI.


Assuntos
Fígado/análise , Espectroscopia de Ressonância Magnética/métodos , Músculos/análise , Trifosfato de Adenosina/análise , Humanos , Fosfatos/análise , Fosfocreatina/análise
20.
NMR Biomed ; 2(3): 112-4, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2641298

RESUMO

The broad phosphorus resonance of isolated perfused liver can be removed by selective presaturation with a DANTE pulse train. The use of the DANTE pulse allows the broad resonance to be removed without the use of multiple RF channels or the ability to switch the observation channel from low to high power.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Animais , Técnicas In Vitro , Fígado/anatomia & histologia , Perfusão , Ratos , Ratos Endogâmicos
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