RESUMO Objetivos: Descrever a anatomia microscópica da inserção femoral do ligamento cruzado posterior a fim de identificar e estabelecer diferenças entre as inserções direta e indireta desse ligamento. Métodos: Foram usados dez joelhos procedentes de amputações transfemorais. A inserção femoral do ligamento cruzado posterior foi observada microscopicamente. A coloração hematoxilina e eosina foi feita para observar a morfologia da inserção do ligamento cruzado posterior. A coloração azul de Alcian foi feita para determinar a localização da matriz de cartilagem e melhor ajudar na observação e diferenciação entre a inserção direta e indireta. Resultados: Observou-se que a inserção direta do ligamento cruzado posterior é uma estrutura mais complexa do que a inserção indireta, por apresentar quatro camadas histológicas distintas (ligamento, fibrocartilagem não calcificada, fibrocartilagem calcificada e osso). Os condrócitos foram observados nas camadas não calcificadas e calcificadas de fibrocartilagem. Foi observado que a inserção indireta, composta de duas camadas nas quais o ligamento está inserido diretamente ao osso por fibras de colágeno, está localizada na região marginal do ligamento cruzado posterior entre a inserção direta e a borda da cartilagem anterior do côndilo. Conclusão: Através de análise histológica, o presente estudo demonstrou que a inserção indireta do ligamento cruzado posterior situa-se adjacente à borda da cartilagem anterior do côndilo femoral e apresenta um padrão histológico no qual as fibras de colágeno se inserem diretamente no osso. A inserção direta encontra-se posterior à inserção indireta e apresenta quatro camadas histológicas distintas.

ABSTRACT Objectives: To describe the microscopic anatomy of the posterior cruciate ligament femoral insertion in order to identify and establish differences between the direct and indirect insertions of this ligament. Methods: Ten cadaveric knees were used for this study. The posterior cruciate ligament femoral insertion was observed microscopically. Hematoxylin and eosin staining was performed to observe the morphology of the posterior cruciate ligament insertion. Alcian blue staining was performed to determine the location of the cartilage matrix and better assist in the observation and differentiation between direct and indirect insertions. Results: The direct insertion was observed to be a more complex structure than the indirect insertion because it showed four different histological layers (ligament, uncalcified fibrocartilage, calcified fibrocartilage, and bone). Chondrocytes were observed in the uncalcified and calcified fibrocartilage layers. It was observed that the indirect insertion was composed of two layers in which the ligament was anchored directly to the bone by collagen fibers. Indirect insertion was located in the marginal region of the posterior cruciate ligament between the direct insertion and the anterior articular cartilage. Conclusion: Through histological analysis, it was demonstrated that the indirect insertion was adjacent to the anterior articular cartilage and presents a histological pattern where the collagen fibers insert directly into the bone (two-layer insertion). The direct insertion is posterior to the indirect insertion and has four histologically distinct layers.

We previously showed urinary activity against Escherichia coli both after oral amoxicillin-sulbactam and sulbactam alone. A study was performed in 10 laboratories from 8 countries to determine the etiology of community acquired lower urinary tract infections (CALUTI) in patients aged 3-to 7 years in South America. Each laboratory sent data from 100 consecutive isolates including susceptibility to amoxicillin and amoxicillin-sulbactam by agar diffusion and also sent 20 consecutive E. coli isolates resistant (R) to amoxicillin-sulbactam to CEA reference laboratory, were MICs were determined for amoxicillin, amoxicillin-sulbactam (2/1) and sulbactam. Urines from 12 volunteers who received a single oral dose 500/500 mg amoxicillin-sulbactam were collected at 0-2; 2-4 and 4-6 h and urinary inhibitory titers (UIT) were determined against 5 R and 1 susceptible (S) isolates from each center. Levels of amoxicillin and sulbactam were determined. Results: Etiology: E. coli 820/1000 (82%) was prevalent; P. mirabilis and K. pneumoniae (4,3% each), S. saprophyticus 4,1% other 5,3%. Diffusion test: 59,4% E. coli were R to amoxicillin, 16,9 intermediate (I) and 23,7 S whereas results for amoxicillin-sulbactam were 28% R; 19,2 I and 52,8 S. MICs: 102 E. coli R to amoxicillin-sulbactam were studied; MIC90s (µg/ml) were the following: amoxicillin > 2.048; amoxicillin-sulbactam 256/128 and sulbactam alone 128. UITs: ranged from > 1/32 at 2 h dose; 1/16-1/4 h and 1/4-1/2 at 6 h against all the isolates. Antibacterial urine levels (µg/ml) obtained for amoxicillin and sulbactam respectively were at 2 h 1.414 and 1.904; at 4 h 691 and 1.257 and at 6 h 462 and 641. Our results confirm the prevalence of E. coli and explain discrepancies between resistance shown by agar diffusion test and clinical success observed in the treatment of CALUTI.