RESUMO
Objective: To investigate the effect of methylation status of breast cancer metastasis suppressor gene 1 (BRMS1) on the expression of breast cancer and the biological behavior of cancer cells in triple-negative breast cancer (TNBC). Methods: The expression of BRMS1 in TNBC tissues and corresponding non-malignant tissues and its relationship with clinicopathological parameters were detected by immunohistochemistry. The mRNA and protein expression of BRMS1 in normal breast epithelial cells and TNBC cells were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The methylation specific polymerase chain reaction (MSP) was used to detect the methylation status of BRMS1 in each cell. These cells were treated with demethylated preparations (5-Aza-dC) to re-activate BRMS1 expression. Using tumor cell invasion assay to detect influence of BRMS1 demethylation on the invasion capacity of cancer cells. The data were statistically analyzed. Results: The positive expression rate of BRMS1 protein in TNBC tissues was significantly lower than that in corresponding non-malignant tissues (χ(2)= 6.635, P<0.05). The mRNA expression level of BRMS1 in patients with lymph node metastasis was significantly lower than those with no lymph node metastasis (P=0.018). The down-regulation of BRMS1 expression was related to the methylation of DNA promoter, which was statistically significant (χ(2)=14.68, P<0.05). The mRNA and protein expression of BRMS1 was also correlated with tumor size and TNM staging (P=0.000-0.003). After using 5-Aza-dC, the number of cells with invasive capacity was significantly lower than those of the control group (t=3.262-10.72, P<0.05). Conclusions: The decrease of BRMS1 expression in TNBC cells is related to the methylation of DNA. Demethylation can inhibit the invasion of breast cancer cells.
Assuntos
Neoplasias da Mama/genética , Metilação de DNA , Proteínas Repressoras/genética , Neoplasias de Mama Triplo Negativas/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Proteínas de Neoplasias , Regiões Promotoras Genéticas , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Female urethral diverticulum is a localized out-pouching of the urethra that is becoming increasingly prevalent, but often poses a diagnostic challenge. Traditionally, conventional voiding cystourethrography has been used to make the preoperative diagnosis. With the development of higher-resolution images acquired through ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI), the anatomy and various abnormalities of the female urethra can be better elucidated. This article focuses on the imaging features of female urethral diverticulum, with emphasis on diagnostic pearls, particularly using MRI. Female urethral diverticulum can be best identified by their location in the posterolateral urethra and by their communication with the urethral lumen. Improved imaging techniques combined with increased physician awareness of urethral diverticulum will lead to more prompt and accurate diagnosis of this entity, leading to better treatment of affected patients.
Assuntos
Diagnóstico por Imagem/métodos , Divertículo/diagnóstico , Doenças Uretrais/diagnóstico , Diagnóstico Diferencial , Divertículo/terapia , Feminino , Humanos , Doenças Uretrais/terapiaRESUMO
Mediation analysis is mainly used to explore the causal mechanism between independent variable X and dependent variable Y. It determines whether mediator M plays a role and evaluate the role's degree in the causal path by decomposing the causal path between the independent variable X and the dependent variable Y. However, the classical mediation analysis is generally used for single mediator. This paper introduces a new mediation analysis method for multiple mediators.
Assuntos
Estatística como Assunto , HumanosRESUMO
At present, traditional methods on statistics have limitations in controlling time- varying confounding. This paper introduces an analysis method, parametric g-formula, which would adjust time-varying confounding, and also exemplifies the steps of its implementation for purpose to provide a new reference for researchers to deal with long-term observational data.
Assuntos
Causalidade , Métodos Epidemiológicos , Estatística como AssuntoAssuntos
Cisto Dermoide/diagnóstico , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias Infratentoriais/diagnóstico , Criança , Meios de Contraste , Cisto Dermoide/patologia , Cisto Dermoide/cirurgia , Diagnóstico Diferencial , Humanos , Neoplasias Infratentoriais/patologia , Neoplasias Infratentoriais/cirurgia , MasculinoRESUMO
Objective: To investigate the clinical characteristics of early term and full term neonates, and analyze the risk factors associated with short term outcomes in early term neonates. Method: Neonates with birth weight (BW) ≥2 500 g from year 2013 were analyzed retrospectively based on American Congress of Obstericians & Gynecologists (ACOG) latest definition of term infants. According to inclusion and exclusion criteria, early term (gestational age 37-38 weeks) and full term(gestational age 39-40 weeks) neonates were included, whose morbidity constituent proportion was analyzed by χ(2) test or Fisher accuracy test or t test or Wilcoxon test. Risk factors associated with short term outcomes in early term population were analyzed by Logistic regression analysis. Result: There were 3 002 discharged term infants being investigated, among whom 1 303 cases were included(768 males and 535 females), and 37, 38, 39 and 40 weeks' gestational age newborns were 160, 324, 450 and 369 respectively. Compared with full term neonates(n=819), early term neonates (n=484) had longer length of hospital stay (LOS)(6.0(5.0, 9.0) vs. 6.0(4.0, 8.0), Z=2.830, P=0.005), higher usage rate of intravenous antibiotics(86.4%(418/484) vs. 80.1%(656/819), χ(2)=8.009, P=0.005), higher assisted ventilation rate(9.5%(46/484) vs. 2.9%(24/819), χ(2)=25.528, P<0.01), higher pulmonary surfactant administration rate(4.3%(21/484) vs. 1.1%(9/819), χ(2)=14.006, P<0.01), as well as higher hypoglycemia incidence(3.9%(19/484) vs. 1.2%(10/819), χ(2)=10.226, P=0.001). There were no statistically significant differences in 1 min Apgar score (9(9, 10)vs. 9(9, 10), Z=0.860, P=0.390), 5 min Apgar score (10(9, 10) vs. 10(9, 10), Z=0.810, P=0.418), white blood cell count (15 (11, 21) ×10(9) /L vs.15 (11, 22) ×10(9) /L, Z=0.880, P=0.379), hemoglobin count(180 (159, 205) vs. 182 (160, 204) g/L, Z=0.560, P=0.576), or platelet count(303(234, 372) ×10(9)/L vs. 301(237, 391) ×10(9)/L, Z=0.550, P=0.584). BW between 2 500 g and 2 999 g(OR 1.69, 95% CI: 1.10-2.62, χ(2) =5.614, P=0.018), wet lung(OR=2.61, 95% CI: 1.61-4.24, χ(2)=15.023, P=0.000)and pneumonia(OR 1.88, 95% CI: 1.14-3.08, χ(2)=6.192, P=0.013) were risk factors in early term neonates' short term adverse outcomes. Conclusion: Early term newborns are still at their "immature" state, and respiratory disorders are major risk factors associated with short term outcomes. Hence, early delivery during 37-38 weeks should be avoided as possible as we can.
Assuntos
Peso ao Nascer , Idade Gestacional , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Tempo de Internação , Masculino , Surfactantes Pulmonares , Respiração Artificial , Estudos Retrospectivos , Fatores de RiscoRESUMO
The majority of the almost 400 confirmed cases of infant botulism in the United States have occurred in California, Pennsylvania, and Utah. In Pennsylvania, 44 of 53 (83%) cases occurred within a geographic area of Southeastern Pennsylvania which represents one tenth of the Commonwealth's area and one third of the population at risk for infant botulism. In Southeastern Pennsylvania, a map of the residences of cases circumscribes a discrete ring around Philadelphia. A case-control study performed to seek host-related risk factors, identifies the significant associations of botulism with infants who are white, breast-fed, and born at term into two-parent families with hospitalization insurance. County control studies were performed to identify differences in host-related factors between areas of high and low prevalence of botulism. Although some "protection" could be afforded Philadelphia infants by their feeding and family characteristics, the differences in case rates between Philadelphia and the botulism "ring counties" cannot be explained entirely by host-related factors. Further, the absence of botulism in counties just outside of the botulism "ring," where infants were found to have identical potential risk factors, suggests that an uneven distribution of botulinal spores in the environment is the most significant determinant of case rate.
Assuntos
Botulismo/epidemiologia , Aleitamento Materno , Família , Humanos , Lactente , Pennsylvania , Fatores SocioeconômicosRESUMO
Forty-four cases of botulism occurred in infants in Southeastern Pennsylvania between 1976 and 1983. Forty-three were caused by Clostridium botulinum type B. Progressive weakness necessitated ventilatory support in 39 infants. Complications during hospitalization included otitis media in 13 patients and aspiration pneumonia in 11. Eight infants developed the syndrome of inappropriate secretion of antidiuretic hormone and two developed adult respiratory distress syndrome. One infant died of progressive bradycardia despite adequate control of ventilation. Manifestations of autonomic nervous system dysfunction recognized on admission to the hospital were constipation, distention of the urinary bladder, and decreased salivation and tearing. During hospitalization, some infants had unexpected fluctuations of skin color, blood pressure, and heart rate. Infants' strength improved despite persistent intestinal elaboration of toxin. C botulinum was isolated from seven of nine home or work environments sampled. All 44 infants were white and were receiving breast milk at the time of onset of symptoms. The majority had first feedings of nonhuman food substances within 4 weeks prior to onset of symptoms. Delineation of fecal flora in seven infants revealed predominance of enterobacteriaceae. Perturbations of intestinal flora during infancy, especially at weaning, may cause transient permissiveness to colonization by C botulinum.
Assuntos
Botulismo/diagnóstico , Toxinas Botulínicas/isolamento & purificação , Botulismo/complicações , Botulismo/microbiologia , Botulismo/fisiopatologia , Clostridium botulinum/isolamento & purificação , Fezes/microbiologia , Feminino , Humanos , Lactente , Masculino , Otite Média/etiologia , Pneumonia/etiologia , Insuficiência Respiratória/etiologia , Fatores de TempoRESUMO
A prospective study of immunogenicity and adverse effects of 1553 doses of diphtheria and tetanus toxoids and whole cell pertussis vaccine (DTP) was performed in 538 children observed longitudinally from 2 months to 20 months of age. Subjects were randomized to the standard four-dose immunization schedule or to a three-dose schedule (with a saline injection substituted for DTP at 6 months of age). The three-dose schedule could not be recommended on the basis of serologic data. Compliance for completing a clinical observation form in the 48 hours following injections was greater than 99%. Fever, local reactions, or adverse behavioral effects were described in association with 96% of DTP doses and 36% of placebo injections. Contraindications to DTP immunization developed in 3% of study children. No convulsion, hypotonic hyporesponsive episode, encephalopathy, or temperature greater than 40.5 degrees C occurred. Behavioral and local inflammatory effects occurred maximally in the first 6 hours following vaccine but fever peaked later. There was no interrelationship between occurrence of local reaction and fever. Data suggest that age has more effect on the type and rate of adverse clinical events than does vaccine dose number. Existing antibody levels to vaccine components, lot of vaccine, breast-feeding, or gestational age did not affect rate or type of clinical reactions. Neither occurrence of reactions nor the use of acetaminophen affected antibody response to vaccine.
Assuntos
Vacina contra Difteria, Tétano e Coqueluche/efeitos adversos , Acetaminofen/uso terapêutico , Fatores Etários , Formação de Anticorpos , Vacina contra Difteria, Tétano e Coqueluche/imunologia , Eritema/induzido quimicamente , Febre/induzido quimicamente , Humanos , Esquemas de Imunização , Lactente , Estudos LongitudinaisRESUMO
OBJECTIVE: We compared the diphtheria and tetanus toxoids and bicomponent acellular pertussis vaccine (DTaP) responses in Japanese and United States infants. DESIGN: This was a double-blind, comparative study. SETTING: Private pediatric practices in Japan and the U.S. participated. SUBJECTS: One hundred eighty-nine healthy 2-month old infants were tested. INTERVENTIONS: Infants were immunized at 2, 4, and 6 months of age. The Japanese formulation (DTaP-J) contained 20 micrograms of pertussis toxin (PT) and 20 micrograms of filamentous hemagglutinin (FHA); the U.S. formulation (DTaP-US) contained 23.4 micrograms of each antigen. Parents used a standard form to record average adverse experiences. Serum was obtained before the first immunization, 2 months after the second immunization, and 1 month after the third immunization. MEASUREMENTS: Differences in DTaP-J and DTaP-US were evaluated in Japanese infants immunized subcutaneously (s.c.). Differences due to ethnicity and to route of administration were compared in U.S. infants immunized with DTaP-US s.c. or intramuscularly (i.m.). An indirect enzyme-linked immunosorbent assay was used to determine immunoglobulin G antibody responses to PT, FHA, and tetanus toxoid. Neutralizing antibody to PT was measured by a Chinese hamster ovary call assay. Diphtheria antitoxin was assayed by serum neutralization on VERO cells. RESULTS: Statistical differences (P < .05) in adverse events included less fatigue after immunization with DTaP-US compared with DTaP-J. Erythema of more than 2.5 cm was more frequent, but erythema less than 2.5 cm was less frequent in Japanese infants compared with U.S. infants. Fewer Japanese infants were febrile ( > 38 degrees C), tired, or irritable. Subcutaneous immunization resulted in a greater frequency of erythema and induration. The DTaP-US resulted in an equivalent response to PT and a greater response to FHA. More Japanese infants demonstrated at least a fourfold response over preimmunization antibody values to FHA. In U.S. infants, antibody responses to the contained pertussis antigens were equivalent after i.m. and s.c. administration. Compared with Japanese infants receiving DTaP-J s.c., U.S. infants receiving DTaP-US i.m. had equivalent responses to PT and a greater response to FHA. CONCLUSIONS: United States infants receiving an i.m. injection of a U.S. -produced bicomponent DTaP vaccine produced antibody responses to the contained pertussis antigens at least equal to those of Japanese infants receiving a similar bicomponent DTaP vaccine shown to be effective in older Japanese children.
Assuntos
Vacina contra Difteria, Tétano e Coqueluche/administração & dosagem , Método Duplo-Cego , Humanos , Lactente , Injeções Intramusculares , Injeções Subcutâneas , Japão , Estados UnidosRESUMO
The safety and efficacy of simultaneous administration of measles-mumps-rubella (MMR), diphtheria-tetanus-pertussis (DTP), and trivalent oral poliovirus (OPV) vaccines in a test group of 405 children were compared with the safety and efficacy of sequential administration of the same vaccines in a control group of 410 children given MMR followed by booster doses of DTP and OPV 2 months later. The study was double blind and placebo controlled with respect to DTP and OPV. Seroconversion rates to measles, mumps, and rubella exceeded 96% in both groups. Geometric mean titers to measles (P = .05) and rubella (P = .004) were higher in the test group, and titers of antibodies to the other seven antigens were similar in both groups. Clinical reaction data were analyzed in 248 of 405 test children and 249 of 410 control children. The rates of serious vaccine-associated reactions were low and similar in the two groups. Some minor side effects were reported more frequently in the test group, but these differences were judged to be related to study design rather than to differences in the safety of the two vaccine schedules. The results indicate that the safety and serologic efficacy of administering MMR simultaneously with reinforcing doses of DTP and OPV in the second year of life is equivalent to the safety and efficacy observed after administering these antigens separately.
Assuntos
Vacina contra Difteria, Tétano e Coqueluche , Esquemas de Imunização , Vacinas/administração & dosagem , Anticorpos/análise , Toxoide Diftérico/administração & dosagem , Método Duplo-Cego , Combinação de Medicamentos/administração & dosagem , Humanos , Imunização Secundária , Lactente , Vacina contra Sarampo/administração & dosagem , Vacina contra Sarampo-Caxumba-Rubéola , Vacina contra Caxumba/administração & dosagem , Vacina contra Coqueluche/administração & dosagem , Vacina Antipólio de Vírus Inativado/administração & dosagem , Distribuição Aleatória , Vacina contra Rubéola/administração & dosagem , Toxoide Tetânico/administração & dosagem , Vacinas/efeitos adversos , Vacinas CombinadasRESUMO
OBJECTIVE: To compare the immunogenicity and reactogenicity of a diphtheria and tetanus toxoids and three-component acellular pertussis vaccine (DTaP) with a diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTwP) when administered as a booster dose to infants 15 through 20 months of age. DESIGN: Randomized, double-blind, comparative study. SETTING: Three pediatric practices (two private; one hospital-based). PARTICIPANTS: One hundred and sixty-five healthy 15- through 20-month old infants. SELECTION PROCEDURES AND INTERVENTIONS: Infants were randomly assigned in a 2:1 ratio to receive vaccine from a single lot of DTaP or from commercially available DTwP. DTaP contained 25 micrograms of pertussis toxoid, 25 micrograms of filamentous hemagglutinin, 8 micrograms of pertactin (69-kilodalton outer membrane protein), 25 flocculating units of diphtheria toxoid, and 10 flocculating units of tetanus toxoid per 0.5-mL dose. DTwP contained one half the concentrations of diphtheria and tetanus toxoids compared with DTaP and a pertussis component with a potency of 4 U/0.5-mL dose. Serum samples were obtained on the day of immunization and 4 weeks later. Adverse reactions were recorded by parents for 7 days after immunization. An interval history was obtained 4 weeks after immunization. MEASUREMENTS AND RESULTS: IgG antibody to pertussis toxoid, filamentous hemagglutinin, pertactin, diphtheria toxoid, and tetanus toxoid was measured by an indirect enzyme-linked immunosorbent assay (ELISA) method. One month after immunization, the geometric mean antibody levels after DTaP compared with DTwP were: pertussis toxoid, 70.6 vs 28 ELISA U/mL (P = .003); filamentous hemagglutinin, 183.4 vs 43 ELISA U/mL (P < .001); pertactin, 216 vs 49.9 ELISA U/mL (P < .001); diphtheria, 14.1 vs 14.9 IU/mL (P = .74); and tetanus, 11.9 vs 14.8 IU/mL (P = .089). After immunization with DTaP, most local and systemic adverse experiences were significantly fewer compared with DTwP (P < .05). CONCLUSIONS: This three-component DTaP vaccine demonstrates significantly greater immune responses to pertussis toxoid, filamentous hemagglutinin, and pertactin, equivalent immune responses to diphtheria and tetanus toxoids, and significantly less reactogenicity compared with a licensed DTwP.
Assuntos
Vacina contra Difteria, Tétano e Coqueluche/efeitos adversos , Vacina contra Difteria, Tétano e Coqueluche/imunologia , Anticorpos Antibacterianos/sangue , Toxoide Diftérico/imunologia , Método Duplo-Cego , Feminino , Humanos , Imunização Secundária , Lactente , Masculino , Toxoide Tetânico/imunologia , Toxoides/imunologiaRESUMO
Incidental to a vaccine study involving 783 immunized children conducted at two study sites, inner city children had significantly higher geometric mean pertussis agglutinin titers compared with suburban children just before the fourth dose of diphtheria-tetanus-whole cell pertussis vaccine (47 vs. 25; P less than 0.001). Higher titers in the inner city were correlated with residence in census tracts where cases of pertussis were reported. Three hundred thirty-two children in a placebo arm of the study who were clinically observed and had paired serum samples taken during a 2- to 4-month period were analyzed for evidence of natural Bordetella infection. Twelve (11%) inner city children and three (1.3%) suburban children had spontaneous 4-fold or greater rises in at least two different pertussis antibodies measured (agglutinin, antitoxin or enzyme-linked immunosorbent assay for IgG to pertussis toxin, IgG and IgA to filamentous hemagglutinin). Eighty percent of these children had IgA to filamentous hemagglutinin. Nine of 12 inner city children with serologic evidence of pertussis lived within 6 blocks of a case of pertussis reported within 1 month of the observed antibody rise in study subjects; none had a household member with pertussis and none had symptomatic disease.
Assuntos
Anticorpos Antibacterianos/sangue , Bordetella pertussis/imunologia , Vacina contra Difteria, Tétano e Coqueluche/imunologia , População Urbana , Coqueluche/epidemiologia , Testes de Aglutinação , Ensaio de Imunoadsorção Enzimática , Hemaglutininas/imunologia , Humanos , Imunoglobulina A/análise , Imunoglobulina G/análise , Lactente , Philadelphia/epidemiologia , População Suburbana , Coqueluche/diagnósticoRESUMO
BACKGROUND: Infections are the major life-threatening complication of burn injury and occur with the greatest frequency in children. Knowledge of their occurrence and management, however, is extrapolated from studies in adults. We performed a prospective study of infectious complications in burned children. OBJECTIVE: To delineate epidemiology, risk factors and microbiology of infections in burned children where burn care and surgical interventions are optimal. METHODS: Children hospitalized for burns were entered into prospective study. Characteristics of the burn injury were assessed, and active surveillance for infections was performed. RESULTS: Seventy patients were entered [mean age, 42 months; mean total body surface area (TBSA), burn 15%]. Twenty-seven percent of patients developed 39 infections: 13 involved the burn wound (burn wound sepsis, 6; graft loss, 5; and cellulitis, 2); 13 were catheter-associated septicemia; 13 involved other sites (i.e. pneumonia, 4; urinary tract infection, 3; bacteremia, 2; endocarditis, 1; myocardial abscess, 1; toxin-mediated syndrome, 1; and otitis media, 1). Twenty-three infections were caused by a single organism, 9 infections by more than 1 organism and in 7 infections defined by CDC criteria no organism was recovered. Organisms causing infection were: Staphylococcus aureus, 19; Candida albicans, 4; Pseudomonas aeruginosa, 4; coagulase-negative Staphylococcus, 4; Enterococcus sp., 3; Escherichia coli, 1; Klebsiella oxytoca, 1; Serratia marcescens, 1; Streptococcus pneumoniae, 1; Streptococcus pyogenes, 1; Aspergillus fumigatus, 1; and Candida parapsilosis, 1. Burn mechanism (flame and inhalation), extent (TBSA >30%) and depth (full thickness) were risk factors for infection; young age and site of burn were not. CONCLUSION: The most common infections occurring in burn children are burn wound infections and catheter-associated septicemia. Characteristics of burn injury predict risk of infection. Children with flame and inhalation injury, TBSA burned >30% and full thickness burns are at high risk of infectious complications.
Assuntos
Queimaduras/complicações , Infecções/etiologia , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Infecções/microbiologia , Estudos Prospectivos , Fatores de RiscoRESUMO
One hundred and seventy-seven bacterial isolates obtained from pediatric burn victims were tested for in vitro susceptibility against bacitracin, silver sulfadiazine, mafenide acetate, nitrofurazone, and mupirocin by two methods: standard microbroth dilution and Nathan's agar well diffusion (NAWD). Nitrofurazone had the broadest spectrum of activity. Mupirocin was the most potent agent against methicillin-susceptible Staphylococcus aureus. Silver sulfadiazine showed activity against gram-positive organisms and higher minimum inhibitory concentration (MIC) values, and smaller zone sizes were seen for methicillin-resistant S. aureus and gram-negative bacilli. Bacitracin showed activity against S. aureus and Streptococcus pyogenes by the microbroth method; activity could not be assessed by NAWD. Mafenide acetate had the highest MICs for all isolates tested. Correlation between methods for all isolates tested was best for mupirocin and nitrofurazone. NAWD was labor intensive and difficult to interpret; MIC method was easy to perform and reproducible. Clinical correlation is necessary to establish breakpoints for interpretation of test results.
Assuntos
Antibacterianos/administração & dosagem , Anti-Infecciosos Locais/administração & dosagem , Queimaduras/microbiologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecção dos Ferimentos/tratamento farmacológico , Administração Tópica , Bacitracina/administração & dosagem , Queimaduras/complicações , Criança , Contagem de Colônia Microbiana , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Enterococcus/efeitos dos fármacos , Enterococcus/isolamento & purificação , Humanos , Técnicas In Vitro , Mafenida/administração & dosagem , Resistência a Meticilina , Testes de Sensibilidade Microbiana , Mupirocina/administração & dosagem , Nitrofurazona/administração & dosagem , Reprodutibilidade dos Testes , Sulfadiazina de Prata/administração & dosagem , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Streptococcus pyogenes/efeitos dos fármacos , Streptococcus pyogenes/isolamento & purificação , Infecção dos Ferimentos/microbiologiaRESUMO
Twenty-three children completed a randomized, prospective, partially blinded study performed to assess the need and effectiveness of antibiotic prophylaxis at the time of burn wound debridement and grafting. Patients with a total body surface area (TBSA) burn less than 35% were randomized to receive cefazolin or placebo. Patients with burns of 35% or more TBSA were randomized to receive cefazolin or targeted antibiotics based on surveillance cultures. Blood cultures were obtained at commencement, immediately after, and 24 hours after surgical debridement. Quantitative cultures and histologic examination of biopsied burn wounds were performed. Burn wound infection occurred in three patients with burns of less than 35% TBSA, two in the cefazolin group and one in the placebo group. Quantitative tissue cultures and histologic examination did not predict either infection. During the four procedures in three patients with 35% or more TBSA, three were randomized to receive cefazolin, and one targeted antibiotics. All receiving cefazolin developed burn wound infection. Quantitative tissue culture was more than 10(5) colony-forming units per gram in all, whereas histologic examination was positive in one. In our patients with less than 35% burn, cefazolin was not necessary, and in those with 35% or more burn, it was not effective.