The sole and combined effects of gelatin-thrombin matrix and freeze-dried bone allograft on early bone healing.

AIMS: Gelatin-thrombin matrix (GTM) is a hemostatic agent with applications in maxillofacial surgery consisting of human-derived thrombin and bovine-derived gelatin matrix. The aim of this study was to evaluate the efficacy of GTM alone or with freeze-dried bone allograft (FDBA) in improving early bone healing. MATERIALS AND METHODS: Forty-six adult male Sprague-Dawley rats were used. All animals were randomly assigned to a control group (n = 4) and three study groups (n = 14). Each group was divided into two subgroups for histomorphometric and histological analyses at weeks 1 and 4. The new bone formation, inflammation, fibrosis, necrosis, foreign body reaction, and bone healing scores were evaluated based on the histopathological findings. Multiple comparisons were performed using the Kruskal-Wallis test. Variables that were not normally distributed were evaluated using the Mann-Whitney U test. RESULTS: At 1 week, the GTM + FDBA group showed less bone formation (mean ± SD: 0.08 ± 0.03 mm2), compared with the study and control groups (FDBA: 0.15 ± 0.06 mm2; GTM: 0.13 ± 0.06 mm2). At 4 weeks, the GTM group (0.48 ± 0.1 mm2) showed more bone formation than the GTM + FDBA group (0.33 ± 0.17 mm2). Foreign body reactions were observed at weeks 1 and 4 in all GTM-containing groups. CONCLUSIONS: Within the limitations of this study, GTM group did not show a significant difference in bone formation compared with the control group. GTM did not inhibit bone healing at 1 and 4 weeks, and no significant difference was observed compared with the control groups. GTM was more effective for bone healing when administered without FDBA. GTM is considered safe when bone hemorrhage is encountered.

Stenotrophomonas maltophilia pneumonia in a premature infant.

Stenotrophomonas (Xanthomonas) maltophilia is an aerobic, non-fermentative, gram-negative bacillus that is generally considered an opportunistic pathogen. Infections due to S. maltophilia have become increasingly important in the hospital environment. Patients compromised by debilitating illnesses, surgical procedures or indwelling vascular catheters are most prone to S. maltophilia infections. To our knowledge, we report the first case of S. maltophilia pneumonia in a premature infant of 31 weeks gestational age. Although the therapy of choice for severe infections caused by S. maltophilia remains to be decided, this patient was successfully treated by amikacin.

Optimal control of artificial aeration in river networks.

Under suitable conditions, artificial in situ aeration is an appropriate and economical method of alleviating water pollution. Regional planning for the control of water pollution can properly consider the use of artificial aeration on a river network in conjunction with other pollution abatement techniques. Application of optimization methods can yield significant savings in the aeration energy consumption required to produce a given level of impact on a polluted river network. The confluence of two rivers, each receiving effluent discharges and subject to artificial aeration control, is first investigated. It is shown that the optimal feedback aeration strategy in one branch of the river system not only depends on measurements of the water quality in that branch, but also on the water quality measurements in the second branch. With these results as the foundation, the optimal aeration control strategy is then determined for a generalized river network modeled as a graphical tree. Various properties of the optimal aeration policy are illustrated by computational examples.