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1.
Burns ; 36(7): 1086-91, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20494521

RESUMO

Prediction of outcome for patients with major thermal injury is important to inform clinical decision making, alleviate individual suffering and improve hospital resource allocation. Age and burn size are widely accepted as the two largest contributors of mortality amongst burns patients. The APACHE (Acute Physiology and Chronic Health Evaluation) III-j score, which incorporates patient age, is also useful for mortality prediction, of intensive care populations. Validation for the burns specific cohort is unclear. A retrospective cohort study was performed on patients admitted to the Intensive Care Unit (ICU) via the Victorian Adult Burns Service (VABS), to compare observed mortality with burns specific markers of illness severity and APACHE III-j score. Our primary aim was to develop a mortality prediction tool for the burns population. Between January 1, 2002 and December 31, 2008, 228 patients were admitted to the ICU at The Alfred with acute burns. The mean age was 45.6 years and 81% (n=184) were male. Patients had severe injuries: the average percent TBSA (total body surface area) was 28% (IQR 10-40) and percent FTSA (full thickness surface area) was 18% (IQR 10-25). 86% (n=197) had airway involvement. Overall mortality in the 7-year period was 12% (n=27). Non-survivors were older, had larger and deeper burns, a higher incidence of deliberate self-harm, higher APACHE III-j scores and spent less time in hospital (but similar time in ICU), compared with survivors. Independent risk factors for death were percent FTSA (OR 1.03, 95% CI 1.01-1.05, p=0.01) and APACHE III-j score (OR 1.04, 95% CI 1.02-1.07, p<0.001). Mortality prediction based on both of these variables in combination was more specific than either individual variable alone (AUROC 0.85, 95% CI 0.79-0.92). Likelihood of death for patients with severe thermal injury can be predicted with accuracy from APACHE III-j score and percent FTSA. Prospective validation of our model on different burn populations is necessary.


Assuntos
APACHE , Queimaduras/mortalidade , Índices de Gravidade do Trauma , Adulto , Fatores Etários , Queimaduras/classificação , Estudos de Coortes , Feminino , Mortalidade Hospitalar , Humanos , Escala de Gravidade do Ferimento , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Análise Multivariada , Valor Preditivo dos Testes , Estudos Retrospectivos
2.
Hum Mutat ; 27(5): 436-43, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16575836

RESUMO

Alagille syndrome (AGS) is caused by heterozygous mutations in JAG1, and mutations have been previously reported in about 70% of patients who meet clinical diagnostic criteria. We studied a cohort of 247 clinically well-defined patients, and using an aggressive and sequential screening approach we identified JAG1 mutations in 94% of individuals. Mutations were found in 232 out of 247 patients studied and 83 of the mutations were novel. This increase in the mutation rate was accomplished by combining rigorous clinical phenotyping, with a combination of mutation detection techniques, including fluorescence in situ hybridization (FISH), genomic and cDNA sequencing, and quantitative PCR. This higher rate of mutation identification has implications for clinical practice, facilitating genetic counseling, prenatal diagnosis, and evaluation of living-related liver transplant donors. Our results suggest that more aggressive screening may similarly increase the rate of mutation detection in other dominant and recessive disorders.


Assuntos
Síndrome de Alagille/genética , Proteínas de Ligação ao Cálcio/genética , Proteínas de Membrana/genética , Mutação , Síndrome de Alagille/diagnóstico , Estudos de Coortes , Análise Mutacional de DNA , Testes Genéticos , Humanos , Hibridização in Situ Fluorescente , Peptídeos e Proteínas de Sinalização Intercelular , Proteína Jagged-1 , Polimorfismo Genético , Proteínas Serrate-Jagged
3.
J Infect Dis ; 182(3): 766-75, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10950770

RESUMO

Immunologic and virologic outcomes of treatment interruption were compared for 5 chronically human immunodeficiency virus (HIV)-infected persons who have maintained antiretroviral therapy-mediated virus suppression, as compared with 5 untreated controls. After a median interruption of 55 days of therapy accompanied by rebound of virus, reinitiated therapy in 4 of 5 subjects resulted in suppression of 98.86% of plasma virus load by 21-33 days and no significant decrease in CD4 T cell percentage from baseline. Increased T helper responses against HIV-1 p24 antigen (P=. 014) and interferon-gamma-secreting CD8 T cell responses against HIV-1 Env (P=.004) were present during interruption of therapy and after reinitiation of treatment. The remaining subject whose treatment was interrupted did not resume treatment and continued to have a low virus load (<1080 HIV-1 RNA copies/mL) and persistent antiviral cell-mediated responses. In summary, cellular immunity against autologous HIV-1 has the potential to be acutely augmented in association with temporary treatment interruption in chronically infected persons.


Assuntos
Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/virologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , HIV-1 , Adulto , Fármacos Anti-HIV/uso terapêutico , Esquema de Medicação , Feminino , Humanos , Imunidade Celular , Interferon gama/metabolismo , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Carga Viral
4.
J Clin Rheumatol ; 6(1): 30-4, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19078446

RESUMO

Blau syndrome (familial granulomatous arthritis, iritis, and rash) was originally described in 1985, in 11 members of a family of Dutch ancestry. Inheritance is autosomal dominant. Several more Caucasian families have been described since. Skin and synovial biopsy specimens show noncaseating sarcoid like granulomas, but the lung is not involved as in classic sarcoidosis. This report describes 3 members of an African American family with Blau syndrome. It is important to differentiate this genetic disorder from other childhood arthritides, such as, juvenile rheumatoid arthritis, juvenile spondyloarthropathies, and early-onset sarcoidosis, because of the need for genetic counseling, treatment and differing potential for selective involvement of other organs (eye, skin, and tendons/joints). All children of an affected individual have a 50% chance of inheriting the disease. Unaffected children do not have to be concerned about subsequent generations being affected. The response to conventional treatments used in juvenile rheumatoid arthritis and to etanercept in our patients has not been satisfactory. Joint disease responds to corticosteroids, but these agents are not suitable for a disease that is lifelong. The eye involvement is aggressive and can lead to blindness. These patients need close follow-up by an ophthalmologist.

5.
JAMA ; 281(2): 151-7, 1999 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-9917118

RESUMO

CONTEXT: With the success of zidovudine chemoprophylaxis for prevention of perinatal transmission of the human immunodeficiency virus (HIV), an increasing number of HIV-exposed but uninfected children will have in utero exposure to zidovudine and other antiretroviral drugs. OBJECTIVE: To evaluate the long-term effects of in utero exposure to zidovudine vs placebo among a randomized cohort of uninfected children. DESIGN: Prospective cohort study based on data collected during Pediatric AIDS Clinical Trials Group Protocol 076, a perinatal zidovudine HIV prevention trial, and Protocol 219, a long-term observational protocol. SETTING: Pediatric research clinics in the United States. PATIENTS: Two hundred thirty-four uninfected children born to 230 HIV-infected women enrolled in Protocol 076 and followed up through February 28, 1997, in Protocol 219 (122 in the zidovudine group and 112 in the placebo group). MAIN OUTCOME MEASURES: Physical growth measurements, immunologic parameters, cognitive/developmental function, occurrence of neoplasms, and mortality data assessed every 6 months for children younger than 24 months and yearly thereafter or as clinically indicated. Baseline echocardiogram and funduscopic evaluations were collected before 36 months of age. RESULTS: Median age of children at time of last follow-up visit was 4.2 years (range, 3.2-5.6 years). There were no significant differences between children exposed to zidovudine and those who received placebo in terms of sequential data on lymphocyte subsets; weight, height, and head circumference z scores; and cognitive/developmental function. No deaths or malignancies occurred. Two children (both exposed to zidovudine) are being followed up for abnormal, unexplained ophthalmic findings. One child exposed to zidovudine had a mild cardiomyopathy on echocardiogram at the age of 48 months; the child is clinically asymptomatic. CONCLUSIONS: No adverse effects were observed in HIV-uninfected children with in utero and neonatal exposure to zidovudine followed up for as long as 5.6 years. Continued prospective evaluations of children born to HIV-infected women who are exposed to antiretroviral or immunotherapeutic agents are critical to assess the long-term safety of interventions that prevent perinatal HIV transmission.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/prevenção & controle , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Complicações Infecciosas na Gravidez/prevenção & controle , Efeitos Tardios da Exposição Pré-Natal , Inibidores da Transcriptase Reversa/uso terapêutico , Zidovudina/uso terapêutico , Contagem de Linfócito CD4 , Linfócitos T CD8-Positivos , Desenvolvimento Infantil , Pré-Escolar , Ecocardiografia , Feminino , Crescimento , Infecções por HIV/tratamento farmacológico , Infecções por HIV/transmissão , Humanos , Lactente , Recém-Nascido , Estudos Longitudinais , Masculino , Gravidez , Complicações Infecciosas na Gravidez/tratamento farmacológico , Resultado da Gravidez , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Testes Visuais
6.
Osteoporos Int ; 9(6): 532-5, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10624461

RESUMO

Nongenetic determinants of quantitative ultrasound (QUS) properties of the bone remain to be identified. The purpose of this study was to determine relationships between early adolescent diet and QUS bone measurements taken in young adulthood. Subjects were participants in the 10-year longitudinal National Heart, Lung, and Blood Institute Growth and Health Study (NGHS). QUS parameters measured at the calcaneus in a convenience subsample of 63 18- to 19-year-old black and white women were correlated with dietary data collected when the subjects were aged 9-11 years. We hypothesized that pre-adolescent intake of calcium, magnesium, vitamin C and protein, nutrients known to be associated with bone development, would be associated with QUS measurements in young women. Stepwise multiple regression analysis, controlling for race, height and weight, demonstrated that pre-adolescent intake of calcium and magnesium were positively related to QUS parameters (calcium with broadband ultrasound attenuation, and magnesium with speed of sound and bone velocity). Our findings suggest that pre-adolescent diet may be associated with bone properties as measured by ultrasound. Further investigations of this relationship may yield a deeper understanding of the impact of diet on skeletal development. The small size of the convenience sample used for the analysis precludes stronger inferences at this time.


Assuntos
Calcâneo/diagnóstico por imagem , Fenômenos Fisiológicos da Nutrição Infantil , Adolescente , Adulto , Cálcio/administração & dosagem , Criança , Dieta , Feminino , Humanos , Estudos Longitudinais , Magnésio/administração & dosagem , Análise de Regressão , Ultrassonografia
7.
J Invest Dermatol ; 111(2): 259-68, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9699727

RESUMO

Having previously associated metabolic oscillations with cell locomotion, we hypothesized that patients with abnormalities in neutrophil trafficking may display aberrant intracellular oscillations. A pyoderma gangrenosum patient exhibiting aberrant leukocyte trafficking in vivo and skin ulceration without infection was identified. This patient's neutrophils constitutively overexpressed and clustered the leukocyte integrins CR3 and CR4 and failed to display appropriate integrin-to-GPI receptor interactions. Increased levels of tyrosine phosphorylation were observed. NAD(P)H oscillations, which are sinusoidal in normals, were chaotic with multiple frequency components in this patient's neutrophils. Normal cell shape and sinusoidal NAD(P)H oscillations were restored by providing a pulsed electric field to drive metabolic oscillations and by temperature reduction. N-acetyl-D-glucosamine disrupted CR3 clusters and sinusoidal NAD(P)H oscillations returned. Anecdotal reports suggest that local hypothermia is clinically useful for this patient. These data define the first metabolic oscillation-associated disease and suggest that pyoderma gangrenosum can be classified as a dynamical disease at the cellular level.


Assuntos
Neutrófilos/fisiologia , Pioderma Gangrenoso/metabolismo , Acetilglucosamina/análise , Adolescente , Movimento Celular , Polaridade Celular , Feminino , Humanos , Antígeno de Macrófago 1/análise , NAD/metabolismo , Fosforilação , Pioderma Gangrenoso/patologia , Temperatura , Tirosina/metabolismo
8.
J Invest Dermatol ; 111(1): 154-8, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9665403

RESUMO

We have previously shown that the beta2 integrins CR3 and CR4 physically and functionally interact with urokinase receptors (uPAR) on neutrophil plasma membranes in an oscillatory fashion. In this study we have analyzed neutrophils from patient SC, a 34 y old African American female, with aberrant skin window results and recurrent perianal abscesses and pretibial lesions diagnosed as pyoderma gangrenosum. Although untreated migrating normal neutrophils exhibited 20 s sinusoidal oscillations in CR4-uPAR proximity, neutrophils from SC demonstrated a faster oscillation (10 s) in the form of a flyback sawtooth wave. This waveform mimicked that observed for normal neutrophils treated with subsaturating doses of the kinase inhibitors staurosporine, genistein, and erbstatin. As beta2 integrins are regulated by phosphorylation, we tested the hypothesis that the aberrant CR4-uPAR proximity oscillations seen in SC's neutrophils are due to defective kinase activity that might be balanced by a decrease in phosphatase activity. When SC's cells are exposed to subsaturating concentrations of the phosphatase inhibitor pervanadate, this caused the CR4-uPAR oscillations to become sinusoidal in shape with a 20 s period, as seen in normal migrating neutrophils. Although SC's neutrophils were deficient in spontaneous and N-formyl-methionyl-leucyl-phenylalanine-induced polarization, 0.5 microM pervanadate returned cell polarization to nearly normal levels, thus paralleling the acquisition of normal receptor interactions. Inasmuch as SC's cellular phenotype is mimicked by kinase inhibitors and corrected by phosphatase inhibitors, we suggest that a mutation(s) affecting the kinetics of intracellular signaling enzymes, but not blocking the pathway per se, may be responsible for this clinical state.


Assuntos
Antígenos CD18/análise , Integrina alfaXbeta2/análise , Neutrófilos/química , Pioderma Gangrenoso/metabolismo , Adulto , Animais , Polaridade Celular , Feminino , Humanos , Camundongos , Receptores de Superfície Celular/análise , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Vanadatos/farmacologia
9.
Appl Environ Microbiol ; 62(11): 4280-3, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8900024

RESUMO

Cell-associated bovine immunodeficiency virus (BIV) and cell-free BIV were subjected to increasing temperatures, including pasteurization conditions. To determine the effect of heat treatment on BIV viability, reverse transcriptase activity and infectivity of the heat-treated virus were assessed. BIV was inactivated by heating to 47 degrees C for 30 min and by low- and high-temperature pasteurization conditions.


Assuntos
Vírus da Imunodeficiência Bovina , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Linhagem Celular , Efeito Citopatogênico Viral , Temperatura Alta , Vírus da Imunodeficiência Bovina/enzimologia , Vírus da Imunodeficiência Bovina/patogenicidade , Infecções por Lentivirus/prevenção & controle , Infecções por Lentivirus/veterinária , DNA Polimerase Dirigida por RNA/metabolismo
10.
J Clin Endocrinol Metab ; 79(3): 703-6, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8077349

RESUMO

The effects of the 5 alpha-reductase inhibitor, finasteride, on scalp skin testosterone (T) and dihydrotestosterone (DHT) levels were studied in patients with male pattern baldness. In a double blind study, male patients undergoing hair transplantation were treated with oral finasteride (5 mg/day) or placebo for 28 days. Scalp skin biopsies were obtained before and after treatment for measurement of T and DHT by high pressure liquid chromatography-RIA. In 10 male subjects studied at baseline, mean (+/- SEM) DHT levels were significantly higher in bald (7.37 +/- 1.24 pmol/g) compared to hair-containing (4.20 +/- 0.65 pmol/g) scalp, whereas there was no difference in mean T levels at baseline. In bald scalp from 8 patients treated with finasteride, the mean DHT concentration decreased from 6.40 +/- 1.07 pmol/g at baseline to 3.62 +/- 0.38 pmol/g on day 28. Scalp T levels increased in 6 of 8 subjects treated with finasteride. Finasteride decreased the mean serum DHT concentration from 1.36 +/- 0.18 nmol/L (n = 8) at baseline to 0.46 +/- 0.10 nmol/L on day 28 and had no effect on serum T. There were no significant changes in scalp or serum T or DHT in placebo-treated patients. In this study, male subjects treated with 5 mg/day finasteride for 4 weeks had significantly decreased concentrations of DHT in bald scalp, resulting in a mean level similar to the baseline levels found in hair-containing scalp.


Assuntos
Inibidores de 5-alfa Redutase , Alopecia/tratamento farmacológico , Di-Hidrotestosterona/metabolismo , Finasterida/uso terapêutico , Couro Cabeludo/metabolismo , Testosterona/metabolismo , Adulto , Alopecia/metabolismo , Di-Hidrotestosterona/sangue , Método Duplo-Cego , Finasterida/farmacologia , Humanos , Masculino , Pessoa de Meia-Idade , Couro Cabeludo/efeitos dos fármacos , Testosterona/sangue
11.
Ann Rheum Dis ; 51(3): 378-83, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1575586

RESUMO

There is a high incidence of staphylococcal infection in children with dermatomyositis, which is limited to those children who either already have or subsequently develop calcinosis. Of 15 children followed up for 3-10 years after diagnosis, all nine who developed calcinosis had infections with Staphylococcus aureus compared with none of six without calcinosis. Of these nine, the occurrence of staphylococcal infections before calcinosis was observed in four, suggested by history in two, and unclear in three children. Granulocyte chemotaxis to Staphylococcus aureus was more severely depressed in those children with calcinosis, whereas those without calcinosis did not differ significantly from controls. The chemotactic defect was due to a serum factor (patients' serum depressed control chemotaxis and control serum corrected the patients' chemotaxis). The nine children with calcinosis also had significantly higher serum IgE concentrations than non-atopic age matched controls; the six without calcinosis did not differ from controls. The increased IgE concentrations appeared to develop after staphylococcal infection and before calcinosis. Two of five patients with calcinosis had increased antistaphylococcal IgE antibodies; neither of the two patients without calcinosis had such increased antibodies. This suggests preceding immunological differences in patients with dermatomyositis who do and do not subsequently develop calcinosis, either increasing susceptibility to Staphylococcus aureus infection or potentially resulting from such infections.


Assuntos
Calcinose/etiologia , Dermatomiosite/complicações , Infecções Estafilocócicas/complicações , Anticorpos Antibacterianos/análise , Calcinose/imunologia , Criança , Pré-Escolar , Dermatomiosite/imunologia , Feminino , Seguimentos , Humanos , Imunoglobulina E/análise , Masculino , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia
12.
Am J Dis Child ; 145(2): 229-31, 1991 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1994694

RESUMO

A 21-month-old infant presented with simultaneous localized scleroderma and severe cardiomyopathy with heart failure. Cardiac abnormalities and serological changes (positive rheumatoid factor assay, elevated IgM and IgG levels, and elevated erythrocyte sedimentation rate) reverted to normal with prednisone therapy, and there was substantial, though incomplete, resolution of her skin changes during the same period. To our knowledge, this is the first patient with definite, clinically significant cardiac involvement associated with focal scleroderma. The possibility of internal organ involvement, including cardiac involvement, must be considered with focal scleroderma as well as with progressive systemic sclerosis.


Assuntos
Cardiomiopatia Dilatada/complicações , Esclerodermia Localizada/complicações , Cardiomiopatia Dilatada/terapia , Feminino , Humanos , Lactente , Esclerodermia Localizada/terapia
14.
Biochem Pharmacol ; 38(22): 4037-44, 1989 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-2480791

RESUMO

The experimental antineoplastic agent triciribine (tricyclic nucleoside, TCN) is known to be activated to its phosphate TCN-P by adenosine kinase and to inhibit cell growth, purine nucleotide synthesis, and incorporation of amino acids into proteins. Our objective in this paper was to compare these effects in intact cells of a human cell line as a prerequisite to describing in a companion paper [Moore et al., Biochem. Pharmac. 38, 4045 (1989)] more detailed enzymic studies of their interrelationships. TCN treatment inhibited cloning of CCRF-CEM human leukemic lymphoblasts 50% at concentrations of 6, 30, and 90 microM with 8-day, 8-hr, and 2-hr exposures respectively. However, 6-20% of the cells survived exposure to 200 microM TCN for 24 hr. The intracellular formation of TCN-P from TCN was rapid, concentrative and essentially complete, but TCN-P did not exceed about 1.4 mM (1.4 nmol/10(6) cells) at 200 microM TCN. In cells exposed to 50 microM TCN for 1.25 to 24 hr, formate incorporation into ATP and GTP was inhibited the most rapidly and strongly; pools of ATP and GTP were decreased as much as 40% (as compared with controls); and incorporation of formate into RNA purines was inhibited as much as 65%. Incorporation of leucine into protein was more moderately inhibited up to 40%, apparently in proportion to the concentration of intracellular TCN-P, rather than of the TCN in the medium. These inhibitions occurred most rapidly during the first 2-4 hr and increased only gradually thereafter, whereas cloning ability was inhibited more slowly and uniformly over a longer time period. No one of these metabolic effects by itself showed a clear correlation with the loss of viability. The incorporation of formate into formylglycinamide ribotide (FGAR, when accumulated at a blockage by azaserine) was inhibited drastically by TCN. The rate of incorporation of hypoxanthine into ATP was increased by TCN, whereas incorporation into GTP was decreased. Thus, the principal sites of inhibition of purine synthesis by TCN-P were shown in these intact cells to be at a step prior to synthesis of FGAR in the de novo pathway and also at an additional site between IMP and GTP.


Assuntos
Antineoplásicos , Leucemia Linfoide/tratamento farmacológico , Linfócitos/efeitos dos fármacos , Biossíntese de Proteínas , Purinas/metabolismo , Ribonucleosídeos/farmacologia , Trifosfato de Adenosina/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Formiatos/metabolismo , Glicina/análogos & derivados , Glicina/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Hipoxantina , Hipoxantinas/metabolismo , Cinética , Leucemia Linfoide/patologia , Linfócitos/metabolismo , Fosforilação , RNA/biossíntese , Ribonucleosídeos/metabolismo , Ribonucleosídeos/uso terapêutico , Ribonucleotídeos/metabolismo , Células Tumorais Cultivadas
15.
Biochem Pharmacol ; 38(22): 4045-51, 1989 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-2480792

RESUMO

We previously reported that triciribine (tricyclic nucleoside, TCN, NSC-154020), after phosphorylation in cultured CCRF-CEM human leukemic lymphoblasts inhibited de novo purine nucleotide synthesis, GTP more than ATP [Moore et al. Biochem. Pharmac. 38, 4037 (1989)]. To determine the enzymes inhibited, triciribine phosphate (TCN-P, NSC-280594) was tested in dialyzed extracts of the cells. A new assay for glycinamide ribotide (GAR) synthesis was based on incorporation of [14C]glycine into GAR as a ribose-containing compound retained on boronyl gel columns. Glutamine, phosphoribosyl pyrophosphate (PRPP), ATP and glycine were required for the two-step sequence of glutamine:amidophosphoribosyltransferase (EC 2.4.2.14) and phosphoribosylamine-glycine ligase (EC 6.3.4.13). When PRPP was near the normal intracellular concentration (0.1 mM), 1.2 mM TCN-P inhibited GAR synthesis by 71-95%. To permit separate assay of the ligase step, 6-diazo-5-oxo-L-norleucine was used to inhibit amidophosphoribosyltransferase and phosphoribosylamine (PRA) was supplied in situ by chemical reaction of ribose-5-phosphate and ammonia (as ammonium acetate). The ligase was not inhibited by TCN-P. Thus, TCN-P inhibits amidophosphoribosyltransferase; it acts as an analog of the purine nucleotides which regulate this first committed step of de novo purine biosynthesis by an allosteric feedback mechanism. The measured intracellular concentration (0.1 mM) of PRPP was not changed in cells treated with TCN. IMP dehydrogenase (EC 1.1.1.205), the first de novo step committed to guanosine nucleotide synthesis, was also tested. It was inhibited by TCN-P, competitively with IMP, 66% at 1.2 mM TCN-P and 8 microM IMP. The degree of inhibition of these two enzymes was sufficient to account for the effects on purine nucleotide biosynthesis observed in intact cells treated with TCN.


Assuntos
Amidofosforribosiltransferase/antagonistas & inibidores , Carbono-Nitrogênio Ligases , IMP Desidrogenase/antagonistas & inibidores , Cetona Oxirredutases/antagonistas & inibidores , Pentosiltransferases/antagonistas & inibidores , Nucleotídeos de Purina/biossíntese , Ribonucleotídeos/farmacologia , Acenaftenos , Trifosfato de Adenosina/metabolismo , Glutamina/metabolismo , Glicina/metabolismo , Humanos , Leucemia Linfoide , Ligases/antagonistas & inibidores , Linfócitos/enzimologia , Fosforribosil Pirofosfato/metabolismo , Ribonucleotídeos/biossíntese , Células Tumorais Cultivadas
16.
Biochem Pharmacol ; 35(16): 2781-7, 1986 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-3527174

RESUMO

Preclinical pharmacologic studies of caracemide [N-acetyl-N-(methylcarbamoyloxy)-N'-methylurea; CAR] have demonstrated a marked instability of this compound in the presence of either phosphate buffer (pH 7.4) or human plasma. Using [1-14C-acetyl]CAR and [3H-methylcarbamoyloxy]CAR, three CAR degradation products were identified: product A, N-(methylcarbamoyloxy)acetamide; product B: N-(methylcarbamoyloxy)-N'-methylurea; and product C: N-hydroxy-N'-methylurea. CAR degradation in human plasma was demonstrated by high-performance liquid chromatography (HPLC) to occur in a time- and temperature-dependent manner. A 30-min incubation (37 degrees) of CAR (10(-4) M) with human plasma resulted in degradation of more than 55% of parent compound; at 1 hr, more than 75% of original CAR was degraded. Incubation of [1-14C-acetyl]CAR with rat brain homogenate resulted in the formation of 14CO2. This reaction was partially inhibited by coincubation with physostigmine (10(-3) M). CAR inhibited acetylcholinesterase activity in neuroblastoma cells with an IC50 of 14 microM. In mechanism of action studies, CAR was found to inhibit ribonucleotide reductase activity but only at nine times the IC50 of hydroxyurea. In contrast to hydroxyurea, CAR was found to be non-cell-cycle phase-specific and non-cross-resistant with two CHO cell lines resistant to hydroxyurea. These data demonstrate the instability of CAR; moreover, they suggest that its mechanism of cytotoxicity is distinctly different from that of hydroxyurea and that the neurotoxicity associated with CAR administration may be caused in part by inhibition of acetylcholinesterase activity.


Assuntos
Antineoplásicos/farmacologia , Hidroxiureia/análogos & derivados , Acetilcolinesterase/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Cricetinae , Cricetulus , Resistência a Medicamentos , Feminino , Humanos , Hidroxiureia/sangue , Hidroxiureia/farmacologia , Técnicas In Vitro , Ovário/efeitos dos fármacos , Ratos
18.
Am J Trop Med Hyg ; 33(6): 1192-7, 1984 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-6391226

RESUMO

An outbreak of dysentery began late in 1979 in Central Africa and spread to involve a major portion of Zaire as well as Rwanda and Burundi. We traveled to a mission hospital in northeast Zaire during the epidemic and isolated Shigella dysenteriae, type 1, from most of the patients studied. All isolates were resistant to ampicillin, tetracycline, chloramphenicol, sulfathiazole, and streptomycin but sensitive to trimethoprim-sulfamethoxazole. Antimicrobial resistance was transferable to Escherichia coli, and at least three plasmids were identified in the donor Shigella isolates by using agarose gel electrophoresis. One was coded for ampicillin, tetracycline, and chloramphenicol resistance while a second conferred resistance to ampicillin and chloramphenicol but not tetracycline. A third large plasmid of approximately 120 megadaltons could not be transferred to E. coli recipients. All S. dysenteriae isolates yielded identical kinetic growth curves when analyzed on the Abbot MS-2 Research System. This is the most extensive outbreak of dysentery caused by S. dysenteriae reported since the Central American epidemic of 1969, and the first epidemic caused by a strain resistant to ampicillin.


Assuntos
Surtos de Doenças/epidemiologia , Disenteria Bacilar/epidemiologia , Adolescente , Adulto , Antibacterianos/uso terapêutico , Burundi , República Democrática do Congo , Resistência Microbiana a Medicamentos , Disenteria Bacilar/tratamento farmacológico , Disenteria Bacilar/microbiologia , Feminino , Humanos , Masculino , Fatores R , Ruanda , Shigella dysenteriae/efeitos dos fármacos , Shigella dysenteriae/genética
19.
Cancer Treat Rep ; 68(10): 1293-4, 1984 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6395952

RESUMO

Caracemide, a new antitumor agent now in clinical trial, was tested against partially purified ribonucleotide reductase from rat Novikoff tumor. It was found to be an active inhibitor, about one-ninth as effective as hydroxyurea.


Assuntos
Antineoplásicos/farmacologia , Hidroxiureia/análogos & derivados , Ribonucleotídeo Redutases/antagonistas & inibidores , Animais , Hidroxiureia/farmacologia , Técnicas In Vitro , Neoplasias Experimentais/enzimologia , Ratos
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