Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Science ; 378(6618): 412-417, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-36302013

RESUMO

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars.

2.
Science ; 378(6618): 417-421, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-36302020

RESUMO

We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilometer depth range, with little depth variation. This implies a higher crustal density than inferred beneath the lander, suggesting either compositional differences or reduced porosity in the volcanic areas traversed by the surface waves. The lower velocities and the crustal layering observed beneath the landing site down to a 10-kilometer depth are not a global feature. Structural variations revealed by surface waves hold implications for models of the formation and thickness of the martian crust.

3.
Bull Seismol Soc Am ; 111(6): 2982-3002, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35001979

RESUMO

The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.

4.
Space Sci Rev ; 215(1): 12, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30880848

RESUMO

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars' surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking's Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars' surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of M w ∼ 3 at 40 ∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11214-018-0574-6) contains supplementary material, which is available to authorized users.

5.
Rev. bras. plantas med ; 15(3): 368-372, 2013. graf
Artigo em Inglês | LILACS | ID: lil-684153

RESUMO

The anti-hyperglycemic effect of wood powder of Quassia amara (QA) was evaluated in normal and in alloxan diabetes-induced rats. After a 12 h fast and glycemic check, the animals were orally given 0.9% of saline (control group), metformin (500 mg/kg) or QA (200 mg/kg) and, 30 minutes later, they received an oral glucose dose (1g/kg). The blood glucose level was measured after 30, 60, 90 and 120 minutes. From the oral glucose dose, QA showed anti-hyperglycemic effects, similar to metformin, only in the diabetic animals (p<0.01) when compared to the control group. Although the anti-hyperglycemic mechanism of action of QA was not investigated, a mechanism similar to metformin can be suggested, since both presented similar results for the conditions tested, that is, normal and diabetic rats. It is believed that the use of QA in diabetics could help to control the blood glucose levels and be useful as an alternative therapy.


O efeito anti-hiperglicemiante do pó do lenho de Quassia amara (QA) foi avaliado em ratos normais e diabéticos aloxana induzidos. Após jejum de 12 horas e verificação da glicemia, os animais receberam administração oral de salina 0.9% (grupo controle), metformina (500 mg/kg) ou QA (200 mg/kg) e 30 minutos depois carga oral de glicose (1g/kg). A glicemia foi medida nos próximos 30, 60, 90 e 120 minutos. A partir da carga oral de glicose, a QA mostrou efeito anti-hiperglicemiante, similar a metformina, somente nos animais diabéticos (p<0.01) quando comparados ao grupo controle. Embora o mecanismo de ação anti-hiperglicemiante da QA não tenha sido investigado, podemos sugerir um mecanismo semelhante à metformina, visto que ambos apresentaram resultados similares nas duas condições testadas, ou seja, animais normais e diabéticos. Acredita-se que o uso de QA, em diabéticos, possa auxiliar no controle da glicemia e servir como terapia alternativa.


Assuntos
Animais , Masculino , Ratos , /análise , Aloxano/efeitos adversos , Diabetes Mellitus/fisiopatologia
6.
Cell Biochem Funct ; 26(2): 228-32, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-17708579

RESUMO

Gluconeogenesis and ketogenesis of in situ rat perfused liver submitted to short-term insulin-induced hypoglycaemia (IIH) were investigated. For this purpose, 24-h fasted rats that received intraperitoneal (ip) regular insulin (1.0 U kg(-1)) or saline were compared. The studies were performed 30 min after insulin (IIH group) or saline (COG group) injection. For gluconeogenesis studies, livers from the IIH and COG groups were perfused with increasing concentrations (from basal blood concentrations until saturating concentration) of glycerol, L-lactate (Lac) or pyruvate (Pyr). Livers of the IIH group showed maintained efficiency to produce glucose from glycerol and higher efficiency to produce glucose from Lac and Pyr. In agreement with these results the oral administration of glycerol (100 mg kg(-1)), Lac (100 mg kg(-1)), Pyr (100 mg kg(-1)) or glycerol (100 mg kg(-1)) + Lac (100 mg kg(-1)) + Pyr (100 mg kg(-1)) promoted glycaemia recovery. It can be inferred that the increased portal availability of Lac, Pyr and glycerol could help glycaemia recovery by a mechanism mediated, partly at least, by a maintained (glycerol) or increased (Lac and Pyr) hepatic efficiency to produce glucose. Moreover, in spite of the fact that insulin inhibits ketogenesis, the capacity of the liver to produce ketone bodies from octanoate during IIH was maintained.


Assuntos
Gluconeogênese/fisiologia , Hipoglicemia/sangue , Corpos Cetônicos/biossíntese , Fígado/metabolismo , Perfusão , Animais , Glicemia/análise , Gluconeogênese/efeitos dos fármacos , Glicerol/sangue , Hipoglicemia/induzido quimicamente , Injeções Intraperitoneais , Insulina/administração & dosagem , Corpos Cetônicos/sangue , Ácido Láctico/sangue , Fígado/efeitos dos fármacos , Masculino , Ácido Pirúvico/sangue , Ratos , Ratos Wistar
7.
Amino Acids ; 33(1): 151-5, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16955228

RESUMO

Our purpose was to determine the blood amino acid concentration during insulin induced hypoglycemia (IIH) and examine if the administration of alanine or glutamine could help glycemia recovery in fasted rats. IIH was obtained by an intraperitoneal injection of regular insulin (1.0 U/kg). The blood levels of the majority of amino acids, including alanine and glutamine were decreased (P < 0.05) during IIH and this change correlates well with the duration than the intensity of hypoglycemia. On the other hand, the oral and intraperitoneal administration of alanine (100 mg/kg) or glutamine (100 mg/kg) accelerates glucose recovery. This effect was partly at least consequence of the increased capacity of the livers from IIH group to produce glucose from alanine and glutamine. It was concluded that the blood amino acids availability during IIH, particularly alanine and glutamine, play a pivotal role in recovery from hypoglycemia.


Assuntos
Alanina/sangue , Glicemia/biossíntese , Gluconeogênese/efeitos dos fármacos , Glutamina/sangue , Hipoglicemia/sangue , Insulina/farmacologia , Fígado/efeitos dos fármacos , Aminoácidos/sangue , Animais , Glicemia/análise , Combinação de Medicamentos , Hipoglicemia/induzido quimicamente , Injeções Intraperitoneais , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar
8.
Cell Biochem Funct ; 25(2): 211-6, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-16397910

RESUMO

The acute effects of isolated and combined L-alanine (L-Ala) and L-glutamine (L-Gln) on liver gluconeogenesis, ureagenesis and glycaemic recovery during short-term insulin-induced hypoglycaemia (IIH) were investigated. For this purpose, 24-h fasted rats that received intraperitoneal injection of regular insulin (1.0 U/Kg) were investigated. The control group (COG group) were represented by rats which received saline. The studies were performed 30 min after insulin (IIH group) or saline (COG group) injection. Livers from IIH and COG groups were perfused with basal or saturating levels of L-Ala, L-Gln or L-Gln + L-Ala (L-G + L-A). The production of glucose, urea, L-lactate and pyruvate in livers from IIH and COG group were markedly increased (p < 0.001) when perfused with saturating levels of L-Ala, L-Gln or L-G + L-A compared with basal levels of the same substrates. In addition, livers from IIH rats showed greater ability in producing glucose and urea from saturating levels of L-Ala compared with L-Gln or L-G + L-A. In agreement with these results, the oral administration of L-Ala (100 mg/kg) promoted better glycaemic recovery than L-Gln (100 mg/kg) or the combination of L-G (50 mg/kg) + L-A (50 mg/kg). It can be concluded that L-Ala, but not L-Gln or L-G + L-A could help glycaemic recovery by a mechanism mediated, partly at least, by the increased gluconeogenic and ureagenic efficiency of L-Ala.


Assuntos
Alanina/administração & dosagem , Gluconeogênese/efeitos dos fármacos , Glutamina/administração & dosagem , Hipoglicemia/tratamento farmacológico , Hipoglicemia/metabolismo , Fígado/efeitos dos fármacos , Alanina/sangue , Animais , Glicemia/análise , Glicemia/biossíntese , Diabetes Mellitus Experimental , Combinação de Medicamentos , Glutamina/sangue , Hipoglicemia/induzido quimicamente , Insulina , Ácido Láctico/metabolismo , Fígado/metabolismo , Masculino , Ácido Pirúvico/metabolismo , Ratos , Ratos Wistar , Ureia/metabolismo
9.
Exp Clin Transplant ; 2(1): 183-8, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15859926

RESUMO

The shortage in cadaveric donor livers is pushing the transplant centers to expand the pool by using "marginal" donors. Primary biliary cirrhosis (PBC) remains an important indication for transplantation. We conducted a retrospective analysis of prospectively collected data in a well-defined group of patients with PBC where 301 consecutive donor-PBC recipient pairs transplanted were analyzed to identify donor and operative factors influencing recipient outcome. Mean follow-up was 56 months. The 1-, 3- and 5-year actuarial patient and graft survival was 93.97%, 90.64%, and 81.75%, and 85.49%, 82.57%, and 75.21%, respectively. Factors showing influence in decreased total patient survival were recipient old age (P = 0.003) and low recipient albumin (P = 0.01). However, the only variables showing an association with decreased patient survival within 90 days are old donor age (P = 0.002) and high donor body weight (P = 0.03) or high body mass index (BMI) (P = 0.055). Cold ischaemic time (CIT) of 18 hours showed statistical significance in patient survival (P = 0.025). Obesity did have a significant adverse impact on survival compared with normal or overweight donors (BMI < 30), decreasing survival by 50% at 5 years. In conclusion, this study of several factors considered "marginal" for transplantation in a recipient population with predictable liver disease (PBC), donor BMI and age were shown to be associated with decreased graft and patient survival.


Assuntos
Cirrose Hepática Biliar/cirurgia , Transplante de Fígado , Doadores de Tecidos , Adulto , Idoso , Envelhecimento , Índice de Massa Corporal , Peso Corporal , Criopreservação , Feminino , Sobrevivência de Enxerto , Humanos , Fígado/fisiopatologia , Cirrose Hepática Biliar/sangue , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo
10.
Bol. Asoc. Méd. P. R ; 95(4): 43-46, Jul.-Aug. 2003.
Artigo em Inglês | LILACS | ID: lil-411124

RESUMO

This is a report of a 60 year-old black female patient presenting with pruritic brownish crusted plaques on both axillae of one month evolution. Histopathology revealed findings characteristic of axillary granular parakeratosis. This entity was first described by Northcutt et al in 1991. Since then, involvement of other intertriginous areas have also been reported. A review of the literature was performed and the term granular parakeratosis is suggested to emphasize its pathognomonic histopathologic features


Assuntos
Humanos , Feminino , Pessoa de Meia-Idade , Paraceratose/patologia
11.
Transplantation ; 72(4): 679-84, 2001 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-11544431

RESUMO

BACKGROUND: Although some centers have reported very good patient and graft survival in liver allograft recipients, reports from both North America (United Network of Organ Sharing) and Europe (European Liver Transplantation Registry) have failed to confirm this. AIM: We have reviewed our experience of liver transplantation in older recipients and compared their clinical outcome to a younger group. METHODS: Retrospective analyses were conducted on 875 consecutive adult patients undergoing liver transplantation for chronic liver disease, between 1990 and 1999. Group I consisted of patients under 60 years of age (n=701; 80.2%) and group II of patients over 60 years (n=174; 19.8%). RESULTS: The proportion of older patients transplanted increased from 10.15% between 1990-1991 to 20.85% (1997-1999). Actuarial graft survival at 1, 3, and 5 years was 78%, 74%, and 69% and 78%, 73%, and 66% for groups I and II, respectively (P=0.49). The overall actuarial patient survival tended to be better in the younger group (1-, 3-, and 5-year survival of 83%, 79%, and 76% for group I and 81%, 75%, and 69% for group II (P=0.07). Crude mortality probability shows a stable trend until 45 years, a gradual increase in mortality between 45 and 60 years, and then the risk of death is accelerated. The same analysis shows the risk of death is between 1.5 and 2 times greater in Child C patients; this is greater in patients aged more than 66 years. CONCLUSION: There is no statistically significant difference in patient or graft survival in patients aged over 60 compared to younger recipients. However, when age is assessed as a continuous variable, an adverse effect of older age is seen on outcome and this effect is more marked in sicker patients.


Assuntos
Envelhecimento/fisiologia , Transplante de Fígado/mortalidade , Adolescente , Adulto , Distribuição por Idade , Idoso , Sobrevivência de Enxerto , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento , Reino Unido
12.
Hepatology ; 33(1): 22-7, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11124816

RESUMO

Orthotopic liver transplantation (OLT) is an effective treatment for patients with advanced primary biliary cirrhosis (PBC). We have conducted a retrospective analysis of 400 consecutive patients transplanted for PBC between 1983 and 1999. Mean follow-up was 56 months. The proportion of patients grafted for PBC fell progressively, from 35% in 1990 (n = 80) to 21% in 1999 (n = 111); comparison of patients grafted in the 2 decades showed that the median age increased from 53 to 56 years and the median serum bilirubin at transplantation fell from 270 micromol/L to 132 micromol/L. The overall actuarial patient and graft survival at 1, 5, and 10 years is 83%, 78%, and 67% and 82%, 75%, and 61%, respectively. The net gain in 5-year survival compared with predicted survival in the absence of transplantation fell from 37% (range, 82%-90%) to 16% (range, 91%-99%). Multiple organ failure (16.1%) and sepsis (9.6%) were the major causes of early deaths (<6 months). Recurrent PBC, diagnosed on allograft histology, was found in 68 (17%) patients, at a mean time of 36 months. We were unable to identify any pretransplantation donor or recipient factor, which identified those patients at risk of recurrence, although recurrence was much earlier and more frequently seen in patients receiving tacrolimus (P =.04). PBC remains a good indication for liver transplantation, with excellent survival rates. The age at transplantation increased although patients tended to be grafted earlier. Survival rates have increased although there is a reduction in the survival benefit. Recurrence may be common, but does not seem to affect medium-term graft survival.


Assuntos
Cirrose Hepática Biliar/cirurgia , Transplante de Fígado , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Padrões de Prática Médica , Recidiva , Encaminhamento e Consulta , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo
13.
Arq Gastroenterol ; 38(4): 247-53, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-12068535

RESUMO

BACKGROUND: Non-alcoholic steatohepatitis was coined in 1980 to describe pathological and clinical features of non-alcoholic disease associated with pathological features, commonly seen in alcoholic-liver disease itself. It is now a well-recognised cause of end-stage liver disease and a rare cause of orthotopic liver transplantation. A small number of cases with recurrent non-alcoholic steatohepatitis following liver transplantation have been reported, however de novo non-alcoholic steatohepatitis in the liver allograft is not well recognised. AIMS/RESULTS: We report four cases of non-alcoholic steatohepatitis following orthotopic liver transplantation describing the factors related with the pathology. The recurrence of fatty infiltration occurred within 21 months and transition from mild steatosis to non-alcoholic steatohepatitis and early fibrosis was observed within 60 months post transplant in all four patients. All four cases had association with one or multiples risk factors (obesity, type 2 diabetes and/or hyperlipidemia). CONCLUSIONS: Management of this risk factors may play a therapeutic role in the prevention of recurrent and de novo non-alcoholic steatohepatitis following orthotopic liver transplantation.


Assuntos
Fígado Gorduroso/patologia , Transplante de Fígado/patologia , Complicações Pós-Operatórias/patologia , Idoso , Biópsia , Complicações do Diabetes , Diabetes Mellitus/patologia , Fígado Gorduroso/etiologia , Feminino , Seguimentos , Hepatite/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Recidiva , Fatores de Risco
14.
BioDrugs ; 14(5): 283-97, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18034574

RESUMO

Liver transplantation is now widely recognised as an effective treatment option for patients with advanced liver disease. Many units now achieve greater than 85% survival at 1 year, with the majority of patients having a high quality of life. The maintenance of a high quality of life requires careful clinical management to ensure that the continued maintenance of excellent liver graft function is not achieved at the expense of immunosuppressive drug complications or morbidity. Acute liver rejection will occur in between 30 to 45% of patients, although with modern immunosuppressive protocols, usually combining one of the calcineurin agents, either cyclosporin or tacrolimus, with both azathioprine and corticosteroids (prednisolone) ensures that relatively few grafts are lost from severe acute rejection. While the incidence and severity of acute rejection may be one factor in raising the risk of chronic rejection, it may not be the principal one in many patients. It is important to recognise that the frequency of rejection also varies with the primary underlying liver disease, with patients with hepatitis B or alcoholic liver disease having relatively low rejection rates, compared with patients with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC), which range between 20 to 70%. Chronic rejection will account for some 5% of grafts lost in the first 3 to 5 years. Indeed, there is some evidence that the incidence of chronic rejection is actually declining over the past few years. While the reason for this apparent decline is uncertain, and it could relate to better immunosuppression management, or more likely to the growing recognition that chronic graft dysfunction may be due to recurrent liver disease, such as autoimmune hepatitis, PBC, PSC, or recurrent hepatitis C. The differentiation of recurrent primary liver disease from chronic rejection can prove to be very difficult in clinical practice. Thus, the clinician must carefully monitor liver and graft function, evaluate any biochemical changes, and try to reach a clear diagnosis before considering any modification of immunosuppressive schedules.

15.
Ophthalmic Surg Lasers ; 28(1): 50-4, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9031305

RESUMO

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate the incidence and characteristics of retinal and choroidal manifestations of toxoplasmosis and/or Mycobacterium avium-intracellulare complex (MAC) in patients with acquired immunodeficiency syndrome (AIDS). PATIENTS AND METHODS: The authors analyzed their prospectively collected data and found 120 patients with new retinal lesions (group A) that were diagnosed 3 months or longer following the diagnosis of MAC and/or toxoplasmic encephalitis. The authors also performed a point prevalence study of retinal/choroidal findings in 25 consecutive AIDS patients (group B) without known eye disease who had been recently treated for toxoplasmic encephalitis and/or disseminated MAC infections. In addition, the characteristics of retinochoroidal toxoplasmosis scars in 5 AIDS patients were studied and compared with the characteristics of scars in 18 immunocompetent patients. RESULTS: In this study the incidence of ocular manifestations of MAC was zero (95% confidence interval [CI] 0.0% to 3.8%). Two of 25 patients (8%) (95% CI 1% to 26%) in group A and 2 of 11 patients (18.1%) (95% CI 3.3% to 51.8%) in group B had toxoplasmic retinochoroiditis. CONCLUSION: In AIDS patients, ocular manifestations of toxoplasmosis are more common than ocular MAC. In addition, when compared with immunocompetent patients, AIDS patients tend to have retinochoroidal scars with less retinal pigment epithelium hyperplasia (1.8+ vs 3+) (P = .03).


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/etiologia , Bacteriemia/complicações , Encefalite/parasitologia , Infecções Oculares Bacterianas/etiologia , Infecção por Mycobacterium avium-intracellulare/complicações , Doenças Retinianas/parasitologia , Toxoplasmose Cerebral/complicações , Toxoplasmose Ocular/etiologia , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adulto , California/epidemiologia , Doenças da Coroide/epidemiologia , Doenças da Coroide/microbiologia , Doenças da Coroide/parasitologia , Infecções Oculares Bacterianas/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Doenças Retinianas/epidemiologia , Doenças Retinianas/microbiologia , Toxoplasmose Ocular/epidemiologia
16.
Retina ; 16(4): 305-11, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8865390

RESUMO

PURPOSE: The authors determine the association, if any, between detection of human cytomegalovirus (CMV) and human immunodeficiency virus (HIV) nucleic acids and retinal lesions in patients with acquired immune deficiency syndrome. METHODS: Postmortem eyes were examined with a dissecting microscope and light microscopy. Retinal cotton-wool spots (CWS) were removed using a clean touch punch biopsy technique. Equivalent amounts of retinal tissue from the posterior pole of the retina not affected by CWS and from the retinal periphery also were studied. Polymerase chain reaction (PCR) detection of retinal cellular DNA (GA3PD gene), human CMV DNA (major immediate early gene), and HIV (gag gene) was performed using ethidium bromide and liquid hybridization detection. RESULTS: Ninety percent of CWS were positive for CMV DNA versus 22% of peripheral retinal biopsies (P < 0.025). Liquid hybridization showed similar results. Analysis of lesions in which results of both tests were positive (ethidium and liquid hybridization) versus lesions in which results of either test were negative also showed a strong association between CWS and CMV, but not HIV nucleic acids (P < 0.02). Studies of HIV showed no association between retinal CWS lesions and HIV nucleic acid; with liquid hybridization HIV, RNA was detected equally at low levels in all areas. CONCLUSION: There is a statistically significant association between the presence of human CMV nucleic acids and retinal CWS detected by PCR. There is a low level presence of HIV in the retinal tissue studied that is only detectable using liquid hybridization techniques and is not associated with a particular area or lesions in the retina; this may represent detection of HIV in blood. The presence of CMV in areas of retinal CWS may have implications for their pathogenesis, but further study is necessary because other explanations are possible.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/virologia , Retinite por Citomegalovirus/virologia , Citomegalovirus/genética , DNA Viral/análise , HIV-1/genética , Reação em Cadeia da Polimerase/métodos , Retina/virologia , Doenças Retinianas/complicações , Infecções Oportunistas Relacionadas com a AIDS/patologia , Biópsia , Citomegalovirus/isolamento & purificação , Retinite por Citomegalovirus/patologia , Primers do DNA/química , HIV-1/isolamento & purificação , Humanos , Imuno-Histoquímica , Retina/patologia
17.
J Infect Dis ; 172(4): 951-6, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7561215

RESUMO

This study evaluated intravitreous and plasma ganciclovir and foscarnet concentrations after intravenous administration in AIDS patients with cytomegalovirus (CMV) retinitis and retinal detachment. Undiluted vitreous samples were prospectively obtained from 60 eyes (52 patients) at the time of pars plana vitrectomy. Thirty-three plasma samples (from 27 patients in the initial group of 52) were obtained simultaneously during surgery on 33 eyes. High-pressure liquid chromatography showed the mean vitreous ganciclovir concentrations in patients on induction and maintenance therapy were, respectively, 4.74 +/- 1.49 microM (n = 24) and 3.29 +/- 1.84 microM (n = 30; P = .005). Simultaneous plasma ganciclovir concentrations were less than the vitreous concentrations in 78% of the patients. The mean intravitreous foscarnet concentrations in patients receiving induction dosages were 189 +/- 177 microM (n = 5) versus 163 +/- 167 microM (n = 4; P > .20) for those receiving maintenance therapy. The foscarnet vitreous plasma concentration ratio averaged 1.43. Current drugs and doses for CMV retinitis result in borderline or progressively subtherapeutic concentrations.


Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Retinite por Citomegalovirus/tratamento farmacológico , Foscarnet/farmacocinética , Ganciclovir/farmacocinética , Descolamento Retiniano/tratamento farmacológico , Corpo Vítreo/metabolismo , Síndrome da Imunodeficiência Adquirida/complicações , Adulto , Retinite por Citomegalovirus/complicações , Quimioterapia Combinada , Feminino , Foscarnet/sangue , Ganciclovir/sangue , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Descolamento Retiniano/complicações
18.
Ophthalmology ; 102(2): 236-45, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7862412

RESUMO

PURPOSE: To determine if scleral buckling is of any benefit in surgical repair of cytomegalovirus (CMV)-associated retinal detachment if combined with vitrectomy, silicone oil, and inferior midperipheral endolaser. MATERIALS AND METHODS: Twenty-two consecutive eyes with CMV-associated retinal detachments were repaired with vitrectomy and endolaser to all breaks and to the inferior midperipheral retina using silicone oil without scleral buckling (group 1, control group) between July 1987 and May 1992. Results were compared with another series of 56 consecutive eyes undergoing vitrectomy, silicone oil injection, endolaser to all breaks, and 360 degrees encircling scleral buckling (group 2, study group) between June 1992 and July 1993. RESULTS: Total retinal reattachment rates were 84% for group 1 and 86% for group 2. Rates of macular reattachment were 91% for group 1 and 91% for group 2. Mean best postoperative refracted visual acuity was 20/66 for group 1 and 20/67 for group 2. Median best postoperative refracted visual acuity was 20/74 for group 1 and 20/80 for group 2. These differences in results between the two groups were not statistically significant. Mean postoperative refractive error was +3.95 for group 1 and +4.92 for group 2. Patients who underwent surgery with the macula attached had a better postoperative visual outcome. CONCLUSION: Scleral buckling may not be necessary in CMV-related retinal detachment if repaired with vitrectomy, silicone oil, and inferior midperipheral endolaser. Elimination of scleral buckling may reduce intraoperative time, patient morbidity, and the risk of an accidental needle stick. Patients with macula-on retinal detachments also should be considered for surgery before macular detachment.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/complicações , Retinite por Citomegalovirus/complicações , Infecções Oculares Virais/complicações , Descolamento Retiniano/cirurgia , Recurvamento da Esclera , Adulto , Fundo de Olho , Humanos , Terapia a Laser , Pessoa de Meia-Idade , Descolamento Retiniano/etiologia , Descolamento Retiniano/patologia , Óleos de Silicone/administração & dosagem , Resultado do Tratamento , Acuidade Visual , Vitrectomia
19.
Pediatr Res ; 29(3): 256-62, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2034473

RESUMO

To study the effects of peroxisome proliferators on fetal biogenesis, 400 mg/kg oral clofibrate was administered to pregnant mice beginning at d 6 of gestation. Maternal/fetal tissues from three separate experiments were harvested between gestational d 13 and 19 and maternal/fetal tissues were assayed for peroxisomal matrix, membrane-associated, and integral membrane proteins. By comparison to control pregnancies that received vehicle only, clofibrate produced a 4- to 5-fold increase in the levels of peroxisomal membrane protein 70, a 1.5- to 2-fold increase of dihydroxyacetone phosphate acyltransferase (DHAP-AT) sp act, and a 1.2- to 1.8-fold increase of catalase sp act in fetal liver of 19 d gestation. Fetal liver endoplasmic reticulum and peroxisomes were also amplified as visualized by electron microscopy. Clofibrate exhibited maximal effects on maternal tissues by 6 d of oral treatment with increases in peroxisomal membrane protein 70 occurring most clearly in maternal liver; DHAP-AT activity was increased in maternal liver, kidney, and brain but not in lung. Slight increases in DHAP-AT activities were evident in fetal brain, lung, and placenta as compared with the greater increases in liver and kidney. There was a general increase in peroxisomal proteins between 13 and 19 gestational d in all fetal tissues except placenta, and the effect of clofibrate was evident by gestational d 13 in lung and placenta. Minimal changes in the activities of acid phosphatase (lysosomal enzyme) or glycerol-3-phosphate acyltransferase (microsomal enzyme) were observed in maternal or fetal tissues although the latter enzyme was increased 10-30% by clofibrate in maternal brain, fetal lung, and placenta.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Transportadores de Cassetes de Ligação de ATP , Clofibrato/farmacologia , Feto/efeitos dos fármacos , Microcorpos/efeitos dos fármacos , Aciltransferases/metabolismo , Animais , Feminino , Feto/metabolismo , Feto/ultraestrutura , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/ultraestrutura , Troca Materno-Fetal , Proteínas de Membrana/metabolismo , Camundongos , Microcorpos/metabolismo , Microcorpos/ultraestrutura , Microscopia Eletrônica , Gravidez
20.
Rev. bras. reumatol ; 23(4): 135-8, 1983.
Artigo em Português | LILACS | ID: lil-18843

RESUMO

Relata-se poliarterite nodosa na infancia associada a endocardite infecciosa descrita em seus aspectos clinicos laboratoriais e histopatologicos.Discutem-se as dificuldades de diagnostico, etiopatogenia, assim como o envolvimento neurologico central e a resposta a terapeutica instituida.com dois modelos e resistencia, sensive


Assuntos
Criança , Humanos , Masculino , Poliarterite Nodosa , Endocardite Bacteriana
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA