RESUMO
The amylosucrase encoding gene from Deinococcus geothermalis DSM 11300 (DgAS) was codon-optimized and expressed in Escherichia coli. The enzyme was employed for biosynthesis of three different dihydroxybenzene glucosides using sucrose as the source of glucose moiety. The reaction parameters, including temperature, pH, and donor (sucrose) and acceptor substrate concentrations, were optimized to increase the production yield. This study demonstrates the highest ever reported molar yield of hydroquinone glucosides 325.6 mM (88.6 g/l), resorcinol glucosides 130.2 mM (35.4 g/l) and catechol glucosides 284.4 mM (77.4 g/l) when 400 mM hydroquinone, 200 mM resorcinol and 300 mM catechol, respectively, were used as an acceptor substrate. Furthermore, the use of commercially available amyloglucosidase at the end of the transglycosylation reaction minimized the gluco-oligosaccharides, thereby enhancing the target productivity of mono-glucosides. Moreover, the immobilized DgAS on Amicogen LKZ118 beads led to a 278.4 mM (75.8 g/l), 108.8 mM (29.6 g/l) and 211.2 mM (57.5 g/l) final concentration of mono-glycosylated product of hydroquinone, catechol and resorcinol at 35 cycles, respectively, when the same substrate concentration was used as mentioned above. The percent yield of the total glycosides of hydroquinone and catechol varied from 85% to 90% during 35 cycles of reactions in an immobilized system, however, in case of resorcinol the yield was in between 65% to 70%. The immobilized DgAS enhanced the efficiency of the glycosylation reaction and is therefore considered effective for industrial application.
Assuntos
Proteínas de Bactérias/metabolismo , Deinococcus/enzimologia , Enzimas Imobilizadas/metabolismo , Glucosídeos/biossíntese , Glucosiltransferases/metabolismo , Microbiologia Industrial/métodos , Proteínas de Bactérias/genética , Deinococcus/genética , Enzimas Imobilizadas/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/metabolismo , Glucosídeos/análise , Glucosídeos/química , Glucosiltransferases/genética , Glicosídeos/análise , Glicosídeos/biossíntese , Glicosídeos/química , Glicosilação , Concentração de Íons de Hidrogênio , Fenóis/análise , Fenóis/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Sacarose/metabolismo , TemperaturaRESUMO
PURPOSE: To evaluate the effectiveness of core decompression using a tantalum trabecular metal system for treatment of early stage osteonecrosis of the femoral head, with a minimum follow-up of 1 year and a maximum follow-up of 5 years. MATERIALS AND METHODS: Between January 2003 and August 2007, a retrospective analysis was conducted on 46 femoral heads in 36 patients (9 males and 27 females) underwent core decompression using a tantalum trabecular metal system. The mean duration of follow-up was 26 months (minimum, 1 year; maximum, 5 years). The ARCO classification system was used. The mean age of the patients was 42.9 years. The conversion to total hip arthroplasty due to aggravating hip pain was defined as a clinical failure. RESULTS: At an average of 12 months, 18 patients (21 hips) were converted to THR. No conversion to THR in occurred in stages IA or IIA. In Stage IB, one-half of the medial lesion and all of the lateral lesions were converted to THR. One of 11 medial lesions and all of the lateral lesions in stage IC were converted to THR; 2 of 3 medial lesions and all of the lateral lesions in stage IIB were converted to THR. In stage IIC, 6 of 8 lateral lesions were converted to THR, but the central lesions were not converted. All of the lateral lesions in stage IIIC were converted to THR. CONCLUSION: The higher stage of ARCO classification and the more lateral position of the lesion, the greater the failure rate of the tantalum trabecular metal system. Conversion to THR from a failed tantalum trabecular system developed within 12 months postoperatively. The tantalum trabecular metal system is a useful treatment for osteonecrosis of the femoral head with a lower stage of ARCO classification and a medial location of the lesion.
Assuntos
Humanos , Masculino , Artemisininas , Artroplastia , Descompressão , Seguimentos , Cabeça , Quadril , Naftoquinonas , Osteonecrose , Estudos Retrospectivos , TantálioRESUMO
Solid and papillary neoplasms of the pancreas, a rare tumor usually found in young female patients, seldom presents with metastasis since it is a tumor with low potential for malignancy. The prognosis for this lesion is much more favorable than that for other pancreatic neoplasms. In an attempt to understand the characteristics and prognosis of this lesion, we reviewed twenty cases treated at the Department of Surgery, Severance Hospital, Yonsei University from 1985 to 1994. The mean age of the patients was 25.6 years (range: 13 to 39 years), and 19 (95%) were women. Chief complaints were palpable mass (50%), pain (45%), and indigestion(5%). In laboratory studies, tumor markers, including CEA, CA125, CA19-9, and aFP were studied in eight patients, and found negative. Other laboratory findings were also nonspecific. These tumors may occur anywhere in the pancreas. In our studies, the tumor was most often located in the tail (45%), and the head (40%) of the pancreas. These were treated by distal pancreatectomy and splenectomy (55%), Whipple's operation (20%), pylorus preserving pancreatoduodenectomy (10%), enucleation (10%) or excision (5%). Significant morbidity or mortality was not observed during hospitalization, and no recurrence or malignant degeneration occurred during the mean follow-up period of 4 years (range: 1 month to 9 years). In conclusion, this study has suggested that the patients with a solid and papillary neoplasm of the pancreas have a good prognosis for successful treatment, if the disease is diagnosed early and the tumor is completely resected. A higher index of suspicion, and more aggressive diagnostic workups are needed in dealing with this disease entity.
