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1.
Genet Med ; 23(11): 2087-2095, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34262154

RESUMO

PURPOSE: Ataxia-Telangiectasia Mutated (ATM) has been implicated in the risk of several cancers, but establishing a causal relationship is often challenging. Although ATM single-nucleotide polymorphisms have been linked to melanoma, few functional alleles have been identified. Therefore, ATM impact on melanoma predisposition is unclear. METHODS: From 22 American, Australian, and European sites, we collected 2,104 familial, multiple primary (MPM), and sporadic melanoma cases who underwent ATM genotyping via panel, exome, or genome sequencing, and compared the allele frequency (AF) of selected ATM variants classified as loss-of-function (LOF) and variants of uncertain significance (VUS) between this cohort and the gnomAD non-Finnish European (NFE) data set. RESULTS: LOF variants were more represented in our study cohort than in gnomAD NFE, both in all (AF = 0.005 and 0.002, OR = 2.6, 95% CI = 1.56-4.11, p < 0.01), and familial + MPM cases (AF = 0.0054 and 0.002, OR = 2.97, p < 0.01). Similarly, VUS were enriched in all (AF = 0.046 and 0.033, OR = 1.41, 95% CI = 1.6-5.09, p < 0.01) and familial + MPM cases (AF = 0.053 and 0.033, OR = 1.63, p < 0.01). In a case-control comparison of two centers that provided 1,446 controls, LOF and VUS were enriched in familial + MPM cases (p = 0.027, p = 0.018). CONCLUSION: This study, describing the largest multicenter melanoma cohort investigated for ATM germline variants, supports the role of ATM as a melanoma predisposition gene, with LOF variants suggesting a moderate-risk.


Assuntos
Ataxia Telangiectasia , Melanoma , Proteínas Mutadas de Ataxia Telangiectasia/genética , Austrália , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Melanoma/genética
2.
Bone Marrow Transplant ; 50(1): 15-9, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25330224

RESUMO

With increasing frequency, allogeneic hematopoietic cell transplantation involving children is being performed in the research setting. Allogeneic hematopoietic cell transplantation, however, cannot be performed without a hematopoietic stem cell (HSC) donor. This donor is often a sibling of the recipient and may also be a child. In such circumstances, it is unclear whether or how the federal regulations for pediatric research apply to the minor donors. This introductory paper reviews the issues to be considered while evaluating studies that use HSCs obtained from minor donors and identifies areas where further research is needed. In the era of increasing applicability for donor-derived cellular therapies, we provide a suggested framework for determining when minor donors qualify as human research subjects and when their participation can be approved under the federal regulations.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas , Doadores Vivos , Adolescente , Criança , Pré-Escolar , Feminino , Transplante de Células-Tronco Hematopoéticas/ética , Transplante de Células-Tronco Hematopoéticas/legislação & jurisprudência , Humanos , Doadores Vivos/ética , Doadores Vivos/legislação & jurisprudência , Masculino
3.
Bone Marrow Transplant ; 50(8): 1013-23, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25822223

RESUMO

Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients.


Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Programas de Rastreamento , Segunda Neoplasia Primária/diagnóstico , Feminino , Humanos , Masculino , Segunda Neoplasia Primária/epidemiologia , Especificidade de Órgãos , Fatores de Risco
4.
J Clin Psychiatry ; 57(6): 241-4, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8666560

RESUMO

BACKGROUND: Indications for computed tomographic (CT) and magnetic resonance (MR) scans of the brain in psychiatric patients are not clearly defined. This survey attempted to refine indications suggested by an earlier survey. METHOD: All brain scans ordered in a psychiatric teaching hospital were surveyed over a period of approximately 23 months. A revised order sheet provided information about the assumed need for scanning as well as indicated those factors from the previous survey most likely to reveal pertinent information. Scan results were later correlated with this information. RESULTS: Of 68 scans reviewed, 40 were normal, 16 equivocal, and 12 were abnormal. Cognitive decline and/or confusion were indications for 30 scans; 7 were abnormal, all meriting a clinical diagnosis of Alzheimer dementia. Only 1 of 12 scans to investigate a history of head injury was abnormal. Only 2 of 11 scans based on a history of seizures were abnormal; all had other possible indications. In one patient a prior stroke was confirmed, and in another, active multiple sclerosis. Ten of the group of 12 abnormal scans were found in patients over the age of 40 years, emphasizing the influence of age. CONCLUSION: Revised indications based on this second survey were as follow: (1) The importance of new or unexplained focal neurologic signs was confirmed; (2) Scans are useful for bolstering a clinical diagnosis of Alzheimer disease; (3) A first psychotic break or personality change after the age of 50 years will require investigation; (4) Cognitive decline in a patient with a prior history of functional psychosis is most likely part of the psychosis rather than a confounding organic disorder; (5) Isolated seizures of long duration or abnormal EEG without other clinical findings are seldom associated with abnormal scans.


Assuntos
Encéfalo/anatomia & histologia , Imageamento por Ressonância Magnética/estatística & dados numéricos , Transtornos Mentais/diagnóstico , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Encefalopatias/diagnóstico , Encefalopatias/diagnóstico por imagem , Encefalopatias/patologia , Criança , Diagnóstico Diferencial , Eletroencefalografia , Estudos de Avaliação como Assunto , Humanos , Transtornos Mentais/diagnóstico por imagem , Transtornos Mentais/patologia , Pessoa de Meia-Idade , Transtornos Neurocognitivos/diagnóstico , Transtornos Neurocognitivos/diagnóstico por imagem , Transtornos Neurocognitivos/patologia , Valor Preditivo dos Testes
5.
J Mass Spectrom ; 33(11): 1141-7, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9835069

RESUMO

Matrix-assisted laser desorption/ionization (MALDI) probe surfaces derivatized with octadecanethiol (C18) can be used as hydrophobic solid-phase extraction devices to isolate and desalt biopolymers directly on the probe surface. Using quantitative MALDI, it was possible to determine the approximate amount of peptide that bound to C18 surfaces and thus to calculate a surface density. It was determined that the amount of peptide bound at the probe surface was independent of the analyte concentration in the immersion solution (from high- to sub-ng ml-1 concentrations), but rather was dependent on the immersion time of the surface as it was exposed to the analyte. The capacity of C18-derivatized probes to bind biopolymers in fixed amounts frees the analyst from the necessity for adjusting analyte concentration through multiple step procedures such as serial dilution or vacuum drying. This time savings result in an overall increase in the efficiency of the MALDI technique.


Assuntos
Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Grupo dos Citocromos c/química , Meia-Vida , Hidrólise , Indicadores e Reagentes , Renina/metabolismo , Propriedades de Superfície , Tripsina
6.
Drug Alcohol Depend ; 45(3): 143-55, 1997 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-9179516

RESUMO

The reinforcing effects of alprazolam were investigated in 14 patients who had generalized anxiety or panic disorder, but were not current users/abusers of other psychoactive substances. Using a double-blind outpatient choice procedure, color-coded alprazolam (0.5 mg) and placebo capsules were provided to patients for use 'as needed' in the treatment of anxiety symptoms. Comparisons of alprazolam and placebo during a 2 week sampling period in which placebo and alprazolam were available sequentially revealed no significant differences on measures of medication usage or anxiety levels, although alprazolam did increase subjective ratings of drug effects side effects. During a 4 week choice period, alprazolam was strongly preferred over placebo in 11 out of 14 patients indicating that alprazolam functioned as a reinforcer. Medication usage ranged from zero to 4.0 mg alprazolam in a day. Variations in daily medication-use were positively correlated with anxiety level fluctuations for a majority of patients. For a majority of patients, the results indicate that alprazolam functioned as a reinforcer without accompanying signs of abuse or addiction.


Assuntos
Alprazolam/uso terapêutico , Ansiolíticos/uso terapêutico , Transtornos de Ansiedade/tratamento farmacológico , Comportamento Aditivo , Transtorno de Pânico/tratamento farmacológico , Reforço Psicológico , Adulto , Análise de Variância , Comportamento de Escolha , Ritmo Circadiano , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Individualidade , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Placebos , Autoadministração/psicologia , Resultado do Tratamento
7.
Oncol Rep ; 5(5): 1025-33, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9683804

RESUMO

Estradiol stimulates the growth of a majority of human breast tumors containing the estrogen receptors (ERs), proteins that mediates estrogen function. Opposing effects of estradiol have been found in cells expressing endogenous ER and those containing a transfected ER. To understand the role of estradiol structure in diverse estrogenic responses related to cell cycle regulation, we evaluated the effects of estradiol and its analogs on cell cycle progression, and the expression of cyclin D1 and the cyclin dependent kinase 4 (CDK4) in ER-positive MCF-7 and ER-transfected MCF-10AEwt5 cells. Four analogs of estradiol, with a re-positioned or a deleted hydroxyl group, were used. Our results show that estradiol and all of the analogs facilitated cell cycle progression of MCF-7 cells. In contrast, only estradiol inhibited the cell cycle progression of MCF-10AEwt5 cells significantly. Western blot analysis revealed that cyclin D1 protein increased to the maximal level by 6 h after the initiation of cell cycle from G1 phase of MCF-7 cells. The least effective analog in inducing cyclin D1 was 3-hydroxyestratriene. However, this analog was most effective at inducing CDK4, contributing to its efficacy in facilitating MCF-7 cell cycle. In contrast to MCF-7 cells, the level of cyclin D1 protein was not influenced significantly by estradiol or its analogs in MCF-10AEwt5 cells. Sucrose gradient sedimentation analysis of ER from MCF-7 cells showed that the major peak of [3H]-estradiol bound to ER could be displaced by a 10-fold excess of unlabelled estradiol or any of the analogs. In contrast, several analogs were less effective than unlabelled estradiol in competitive displacement of [3H]-estradiol bound to ER from MCF-10AEwt5 cells. These data indicate that the induction of cyclin D1 is an important part of the growth stimulatory effects of estrogens in MCF-7 cells, but it may not be involved in growth inhibition of MCF-10AEwt5 cells. Our results also show that estrogenic compounds interact with ER from MCF-10AEwt5 cells with altered ligand binding affinity, possibly due to the absence or dysfunction of certain transcription factors or ER-associated proteins that co-regulate ER function.


Assuntos
Ciclina D1/biossíntese , Quinases Ciclina-Dependentes/biossíntese , Estradiol/análogos & derivados , Estradiol/farmacologia , Proteínas Proto-Oncogênicas , Receptores de Estrogênio/fisiologia , Neoplasias da Mama , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Quinase 4 Dependente de Ciclina , Feminino , Humanos , Cinética , Receptores de Estrogênio/biossíntese , Proteínas Recombinantes , Fatores de Tempo , Transfecção , Células Tumorais Cultivadas
8.
J Food Prot ; 64(9): 1392-8, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11563517

RESUMO

The microbial integrity of many types of flexible food packages depends on a zero defect level in the fused seam seal. Human inspection for defects in these seals is marginal at best, and secondary incubation protocols are often used to spot packages with compromised integrity before releasing product for sale. A new type of inspection method has been developed and is being evaluated for robustness. The purpose of the study was to evaluate a new raster scanning geometry to simulate continuous motion, online ultrasonic inspection of the seal region in flexible food package seals. A principal engineering tradeoff of scanning inspection systems is between increased line speed that results from decreased spatial sampling (less acquired data to process) and decreased image quality. The previously developed pulse-echo Backscattered Amplitude Integral (BAI) mode imaging technique is used to form ultrasound images using the new scanning geometry. At an ultrasonic frequency of 22.9 MHz, 38- and 50-microm-diameter air-filled channel defects in all-plastic transparent trilaminate are evaluated. The contrast-to-noise ratio (CNR) of the processed BAI-mode image is used to quantify image quality as a function of spatial sampling. Results show seal defects (38- and 50-microm diameter) are still detectable for undersampled conditions, although image quality degrades as spatial sampling decreases. Further, it is concluded that the raster scanning geometry is feasible for online inspection.


Assuntos
Contaminação de Alimentos/prevenção & controle , Embalagem de Alimentos , Ultrassonografia/instrumentação , Ultrassonografia/métodos , Microbiologia de Alimentos
9.
J Assoc Physicians India ; 47(3): 275-9, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10999119

RESUMO

BACKGROUND: The availability of sensitive and specific assays for evaluation of the thyroid axis has allowed definition of thyroid disorders at subclinical stage. This has almost obviated the use of thyrothrophin releasing hormone (TRH) study. We describe here a group of patients with minimal signs of hypothyroidism having normal thyroid function tests (T3, T4, thyroid stimulating hormone (TSH)) and have shown exaggerated TSH response to TRH. MATERIAL AND METHODS: Total 82 subjects were studied. Of these, 11 were age and sex matched controls, and 71 were patients. In all subjects TSH and other thyroid assays (T3, T4, FT4) were done by immunoradiometric assay (IRMA), and radioimmunoassay (RIA) respectively. Thyroid antibody was carried out by haemagglutination method. Results were compared to age and sex related normal ranges. To further investigate the status of thyroid axis, TRH study was carried out using standard protocol. RESULTS: Based on TRH study patients were grouped in three categories. Group 1 included 29 patients whose TSH response to TRH was normal. Group 2 included 20 patients with normal baseline TSH and exaggerated TSH response to TRH and Group 3 included 18 patients with baseline TSH in the range of 5 to 10 mu IU/ml and exaggerated TSH response to TRH. There was a significant difference to total T3 between group 1 and 3 (p < 0.05) but mean values were within normal limits. While no significant difference was observed in total T4 between controls and patient's group. Serum TSH values were high in group 3 as compared to controls and Group 1 and 2 (p < 0.0001). For Free T4 no statistical significance was observed between Group 1, 2 and 3. Thyroid antibodies were positive in 22.7% of patients in Group 2 and 33.33% in Group 3. CONCLUSION: We conclude from the present study that even with sensitive TSH assays TRH study still has a role to mark the early stage of hypothyroidism. Those with a normal or upper normal TSH with exaggerated response to TRH are termed as sub-biochemical hypothyroidism and can be considered for thyroid replacement therapy.


Assuntos
Hipertireoidismo/diagnóstico , Hormônio Liberador de Tireotropina , Tireotropina/sangue , Tireotropina/efeitos dos fármacos , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Hipertireoidismo/sangue , Masculino , Pessoa de Meia-Idade , Probabilidade , Radioimunoensaio , Valores de Referência , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Testes de Função Tireóidea
10.
J Assoc Physicians India ; 39(7): 546-8, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1800501

RESUMO

The objective of the study was to compare the enteric coated diclofenac sodium (Voveran), the slow release formulation developed in India (Voveran SR) and the internationally marketed formulation Voltaren Retard. Ten healthy volunteers were administered 100 mg each of the three formulations in a three-way crossover fashion. Blood samples were collected over 24 hours following administration of the drug; plasma levels of unchanged drug were determined by gas chromatography. Pharmacokinetic parameters for the three formulations were compared. The extent of the drug available from the three formulations was the same as the mean AUC values were not significantly different. Cmax and MRT values for the two slow release formulations were comparable but were significantly different from the values obtained with the enteric coated formulation. Tmax values for the two slow release formulations were similar while the enteric coated tablet had faster time to peak. Voveran SR is comparable to Voltaren Retard and has the distinct advantage of a slow release formulation in that its Cmax is much lower and levels are maintained over 12 hours and detectable upto 24 hours. This slow release formulation will offer clinical advantages of better compliance, relief of early morning symptoms and better tolerability over long term usage.


Assuntos
Diclofenaco/farmacocinética , Adulto , Disponibilidade Biológica , Preparações de Ação Retardada , Diclofenaco/administração & dosagem , Diclofenaco/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Comprimidos com Revestimento Entérico , Fatores de Tempo
16.
J Bone Joint Surg Br ; 91(7): 865-9, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19567848

RESUMO

In 2004 we described the ten-year prospective results of 38 total hip replacements using the Furlong hydroxyapatite-ceramic-coated femoral component in 35 patients < 50 years old. We have now reviewed the surviving 35 arthroplasties in 33 patients at a mean of 16 years (10.3 to 19.9). The mean age of the surviving patients at the time of operation was 41.3 years (26.0 to 49.0). Of these, eight have undergone revision of their acetabular component for aseptic loosening. None of the femoral components has had revision for aseptic loosening giving a survival rate of 100% at 16 years (95% confidence interval 89% to 100%). The Furlong hydroxyapatite-ceramic-coated femoral component gives excellent long-term survival in young and active patients.


Assuntos
Cerâmica/uso terapêutico , Materiais Revestidos Biocompatíveis/uso terapêutico , Durapatita/uso terapêutico , Articulação do Quadril/cirurgia , Adulto , Artroplastia de Quadril/métodos , Feminino , Seguimentos , Articulação do Quadril/diagnóstico por imagem , Prótese de Quadril , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia , Análise de Sobrevida , Resultado do Tratamento , Adulto Jovem
17.
J Bone Joint Surg Br ; 90(9): 1137-42, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18757951

RESUMO

We report the outcome at a minimum of five years of 110 consecutive metal-on-metal Birmingham Hip Resurfacing arthroplasties in 98 patients. The procedures were performed between October 1999 and June 2002 by one surgeon. All patients were followed up clinically and radiologically. The mean follow-up was 71 months (60 to 93). Revision of either component was defined as failure. The mean Harris Hip score at follow-up was 96.4 (53 to 100). The mean Oxford hip score was 41.9 (16 to 57) pre-operatively and 15.4 (12 to 49) post-operatively (p < 0.001). The mean University of California Los Angeles activity score was 3.91 (1 to 10) pre-operatively and 7.5 (4 to 10) post-operatively (p < 0.001). There were four failures giving a survival at five years of 96.3% (95% confidence interval 92.8 to 99.8). When applying a new method to estimate narrowing of the femoral neck we identified a 10% thinning of the femoral neck in 16 hips (14.5%), but the relevance of this finding to the long-term outcome remains unclear. These good medium-term results from an independent centre confirm the original data from Birmingham.


Assuntos
Artroplastia de Quadril/métodos , Prótese de Quadril , Adulto , Idoso , Artrite Psoriásica/diagnóstico por imagem , Artrite Psoriásica/cirurgia , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/cirurgia , Artroplastia de Quadril/efeitos adversos , Inglaterra , Feminino , Seguimentos , Luxação Congênita de Quadril/diagnóstico por imagem , Luxação Congênita de Quadril/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/diagnóstico por imagem , Osteoartrite do Quadril/cirurgia , Osteonecrose/diagnóstico por imagem , Osteonecrose/cirurgia , Falha de Prótese , Radiografia , Reoperação , Resultado do Tratamento
18.
Appl Environ Microbiol ; 56(4): 858-63, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16348172

RESUMO

F(420)-nonreactive and F(420)-reactive hydrogenases have been partially purified from Methanococcus jannaschii, an extremely thermophilic methanogen isolated from a submarine hydrothermal vent. The molecular weights of both hydrogenases were determined by native gradient electrophoresis in 5 to 27% polyacrylamide gels. The F(420)-nonreactive hydrogenase produced one major band (475 kilodaltons), whereas the F(420)-reactive hydrogenase produced two major bands (990 and 115 kilodaltons). The F(420)-nonreactive hydrogenase consisted of two subunits (43 and 31 kilodaltons), and the F(420)-reactive hydrogenase contained three subunits (48, 32, and 25 kilodaltons). Each hydrogenase was active at very high temperatures. Methyl viologen-reducing activity of the F(420)-nonreactive hydrogenase was maximal at 80 degrees C but was still detectable at 103 degrees C. The maximum activities of F(420)-reactive hydrogenase for F(420) and methyl viologen were measured at 80 and 90 degrees C, respectively. Low but measureable activity toward methyl viologen was repeatedly observed at 103 degrees C. Moreover, the half-life of the F(420)-nonreactive hydrogenase at 70 degrees C was over 9 h, and that of the F(420)-reactive enzyme was over 3 h.

19.
Am Heart J ; 92(1): 73-8, 1976 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-961578

RESUMO

The amplitude and duration of P waves in Leads II (P II), P terminal force in V1, (PV1) and the sums of P II and PV1 were compared in 37 subjects with left atrial size obtained by echocardiographic technique in 36 instances and with hemodynamic estimates of pulmonary capillary wedge pressures in 16 cases. The 22 females and 15 males were subdivided into the following groups. Group I, four normal subjects, Group II, 11 patients with predominant aortic insufficiency (two of whom had a mild mitral insufficiency); Group III, 14 patients with mitral valve disease, seven of whom had mitral insufficiency (two with minimal aortic insufficiency) Group IIIa) and seven had mitral stenosis (Group IIIb); Group IV, eight patients with miscellaneous disorders, i.e., coronary artery disease (5), hypertension (2), and idiopathic hypertrophic subaortic stenosis (1). Good correlations were obtained between left atrial size and P in Lead II (P II) (r = 0.74; p less than 0.001) and between P terminal force in V1 (PV1) and left atrial size (r = -0.69; p less than 0.001). In Group IV good correlation between PV1 and atrial size was noted. Some correlation between the sum of P II and PV1 and left atrial size (r = 0.51; p less than 0.02) was noted, but a better correlation was obtained in the patients with aortic insufficiency (r = 0.80; p less than 0.01). Pulmonary capillary wedge pressures were not reflected in changes in P II or PV1, except for the group with mitral stenosis (Group IIIb). Adding P II to PV1 improved the correlation with wedge pressure for the entire group.


Assuntos
Eletrocardiografia , Átrios do Coração/fisiopatologia , Doenças das Valvas Cardíacas/fisiopatologia , Adulto , Idoso , Cateterismo Cardíaco , Ecocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pressão
20.
Biotechnol Bioeng ; 49(2): 161-71, 1996 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-18623566

RESUMO

Methanotrophs have promising applications in the bioremediation of chlorinated hydrocarbons and in the production of a biopolymer, poly-beta-hydroxybutyrate (PHB). Batch bioreactor culture conditions were studied for the accumulation of PHB by methane-grown Methylosinus trichosporium OB3b, and to evaluate the effect of PHB on the bacterial capacity to degrade trichloroethylene (TCE), a common groundwater contaminant. The PHB content of the washed and lyophilized cells was measured by gas chromatography (GC), after hydrochloric acid (HCl) propanolysis. A differential GC-based assay was developed for the monomer and the polymer of beta-hydroxybutyrate utilizing 1% and 10% HCl (v/v) reaction mixtures, respectively. During bioreactor growth in a Cu-deficient modified Higgins' medium, the cells accumulated PHB upon depletion of nitrate. A biomass yield of 3.2 g dry wt/L and a PHB accumulation of approximately 10% (w/w) were reached after 140 to 160 h, without adversely affecting the propene or TCE epoxidation specific rate given by whole cells containing soluble methane monooxygenase (sMMO). The TCE biotransformation capacity ( approximately 0.25 mg TCE oxidized/mg dry cell wt) of resting cells containing approximately 10% PHB was consistently approximately 1.6-fold greater than that of cells containing only approximately 2% PHB. Higher levels (>10%) of accumulated PHB did not enhance this biotransformation capacity further. By replacing the bioreactor inlet air + CO(2) mixture with pure O(2) at approximately 85 h of batch operation, a PHB accumulation of approximately 45% was achieved after 160 h, but the whole-cell sMMO activity was markedly decreased. In contrast, cells grown in a 10 muM Cu-supplemented Higgins' nitrate minimal salts medium (particulate MMO formation) accumulated up to 50% PHB in only 120 h, coupled with a very high biomass yield of 18 g dry cell wt/L. High PHB accumulations above approximately 20% by both the -Cu and the +Cu grown cells resulted in a decreased ratio of the electronic cell count to the absorbance at 660 nm, which is commonly used to monitor bacterial growth. (c) 1996 John Wiley & Sons, Inc.

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