In Vitro and In Vivo Study of Argyreia speciosa on Chronic Gastric Ulceration and Metabolic Studies

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Chronic gastric ulcer being the most prevalent gastrointestinal disorder is considered a major cause of...     

Influence of Strain Gradient on Fatigue Life of Carbon Steel for Pressure Vessels in Low-Cycle and High-Cycle Fatigue Regimes

This paper discusses how the strain gradient influences the fatigue life of carbon steel in the low-cycle and high-cycle fatigue regimes. To obtain fatigue data under different strain distributions, cyclic alternating bending tests using specimens with different thicknesses and cyclic tension–compression tests were conducted on carbon steel for pressure vessels (SPV235). The crack initiation life and total failure life were evaluated via the strain-based approach. The experimental results showed that the crack initiation life became short with decreasing strain gradient from 10² to 10⁶ cycles in fatigue life. On the other hand, the influence of the strain gradient on the total failure life was different from that on the crack initiation life: although the total failure life of the specimen subjected to cyclic tension–compression was also the shortest, the strain gradient did not affect the total failure life of the specimen subjected to cyclic bending from 10² to 10⁶ cycles in fatigue life. This was because the crack propagation life became longer in a thicker specimen. Hence, these experimental results implied that the fatigue crack initiation life could be characterized by not only strain but also the strain gradient in the low-cycle and high-cycle fatigue regimes.     

Antigenic cell associated dengue 2 virus proteins detected in vitro using dengue fever patients sera

At least three major antigenic dengue 2 virus proteins were recognized by pooled dengue fever patients' sera in infected Aedes albopictus (C6/36) mosquito cells. Dengue virus envelope (E), premembrane (PrM) and non-structural protein 1 (NS 1) dimer were detected beginning on day 3 postinfection in both the cell membrane and cytosolic fractions. Using the patients' sera, the presence of antigenic intermediate core protein (C)-PrM and NS1-non-structural protein 2a (NS2a) in the cytoplasmic fraction of dengue 2 virus infected cells was revealed. The presence of a approximately 92 and approximately 84 kDa NS 1 dimer in the membrane (NS 1m) and cytosolic (NS 1c) fractions of C6/36 cells, respectively, was also recognized. Using individual patient's serum, it was further confirmed that all patients' sera contained antibodies that specifically recognized E, NS 1 and PrM present in the dengue 2 virus-infected cell membrane fractions, suggesting that these glycosylated virus proteins were the main antigenic proteins recognized in vivo. Detection of dengue 2 virus C antibody in some patients further suggested that C could be antigenic if presented in vivo.     

Arginine selective biosensor based on arginase-urease immobilized in gelatin

Arginase and urease enzymes were immobilized on the surface of pH electrode by using gelatin membrane which is then cross-linked with glutaraldehyde. Sensor response was maximum when 2.5 mM, Tris-HCl buffer (pH 8.5) was used at 25 degrees C. The biosensor response depends linearly on arginine concentration between 0.025-0.310 mM with response time 10 min. Furthermore, application of the system for the arginine detection in serum samples was also tested.     

Comparison of chitin and Amberlite IRA-938 for alpha-galactosidase immobilization

Watermelon alpha-galactosidase (EC 3.2.1.22) was immobilized on a natural (chitin) and a synthetic anion-exchange (Amberlite IRA-938) support by covalent coupling methods. The procedure entails the activation of supports with 1,1'-carbonyldiimidazole (CDI), followed by immobilization of the enzyme on to these supports without and with a spacer arm; gamma-aminobutyric acid (GABA). Optimization of activation was performed by changing the CDI concentrations and coupling efficiencies. The comparison of two immobilization techniques for both chitin and Amberlite IRA-938 was made by comparing different enzyme concentrations against enzyme activity yield. Furthermore, the storage stability of the immobilized enzymes was also investigated and chitin immobilized alpha-galactosidase was found to be better. Although the activity yield of immobilized enzymes were the same for both supports, the short storage stability of immobilized enzyme on Amberlite IRA-938 is currently a drawback to its applications.     

Local versus general anesthesia for carotid endarterectomy: report of 329 cases

Since stroke is an important cause of morbidity and mortality, carotid endarterectomies are used frequently to reduce the risk of stroke and death. Unfortunately, an inherent risk of the carotid endarterectomy procedure is that surgery itself may result in stroke. At this point the question is which method of anesthesia, local or general, is better to protect and monitorize the brain function during cross-clamp period in carotid endarterectomies? In the authors' center, 365 carotid endarterectomies were applied to 329 patients between 1990 and 2001; 165 operations were done under general anesthesia and the other 200 operations were done under local anesthesia. These 2 groups, general (group I) and local anesthesia (group II), were studied retrospectively according to preoperative and postoperative data. In group I, the rate of major stroke was 7.3%, but this rate was 1% in group II (p < 0.05). Intraoperative shunts were used in 50 (30.3%) operations of group I, but the usage of shunt was 8% (16 operations) in group II (p < 0.0001). The hospitalization period was also much shorter in group II than in group I. The time of hospitalization was 4.1 +/-1.9 days in group I and 2.4 +/-1.1 days in group II (p < 0.0001). In terms of cost analysis, the mean costs were 1007.14 dollars +/-135.71 dollars in group I and 885.71 dollars +/-78.57 dollars in group II (p < 0.0001). In short, the local procedure was more cost-effective. As a result, in carotid endarterectomy procedures, the authors prefer local anesthesia to achieve better brain function monitoring and to reduce hospitalization time and cost.     

Association of donor TNFRSF6 (FAS) gene polymorphism with acute rejection in renal transplant patients: a case-control study.

BACKGROUND: Genetic factors other than HLA have been reported to be associated with the outcome of organ transplantations. Because binding of FasL to its receptor Fas could play an important role in tubulitis and in the death of graft tubular epithelial cells during kidney allograft rejection, a gene polymorphism recently identified in position -671 in the promoter of the TNFRSF6 gene coding for Fas was investigated in donors. METHODS: A case-control study was performed within a cohort of non-hyperimmunized adult patients who had received cadaveric kidney transplants based on the occurrence or absence of acute cellular rejection in the first 6 months after renal transplantation. Each recipient from the acute rejection group (n = 35) was matched for age (+/- 5 years) and number of HLA-DR mismatches with two recipients within the non-acute rejection group (n = 70). RESULTS: The TNFRSF6-GG genotype was more frequent in donors in the group without rejection episodes. In contrast, patients who received a kidney from a TNFRSF6-A carrier were more likely to experience acute rejection episodes (relative risk nearly 2.1). CONCLUSION: This study suggests that donor TNFRSF6 polymorphism directly or indirectly influences acute kidney rejection episodes.     

The role of posterior instrumentation and fusion after anterior radical debridement and fusion in the surgical treatment of spinal tuberculosis: experience of 127 cases

Long periods of immobilization, progressive kyphosis and graft failure are the major postoperative problems encountered after anterior radical surgical treatment for tuberculosis of the spine. Posterior fusion and instrumentation can be an effective solution for these problems. Effectiveness of posterior fusion and instrumentation was investigated in this study on the basis of the cases with anterior procedure only, and with combined anterior-posterior procedures. One hundred twenty-seven cases of tuberculosis of the spine were surgically treated between 1987 and 1995. All had either 1 or more of conditions such as spinal cord compression and neurological deficit, vertebral body collapse and kyphosis, or wide paravertebral abscess unresponsive to medical treatment. Of these, 57 had only anterior radical procedure between the years 1987 and 1993. Seventy cases had posterior instrumentation and fusion after the anterior procedure between the years 1991 and 1995. In about two third of the patients (81) autogenous iliac strut graft and in one third of them (40) autogenous fibular strut graft (cases with more than 2 level involvement) was used along with rib grafts after debridement. Twenty-one of the 57 patients who had only anterior procedure demonstrated a postoperative increase of kyphosis of more than 10 degrees. Increased kyphosis was due to graft slippage in 3, resorption in 2 and subsidence in 16 patients. No such increase or graft failure was noted in cases of combined anterior-posterior procedure. The difference in terms of kyphosis was found to be statistically significant (P=0.047). Anterior radical debridement and strut graft is the golden standard in the surgical treatment of spinal tuberculosis, but it should always be accompanied by posterior instrumentation and fusion to shorten the immobilization period and hospital stay, obtain good and long lasting correction of kyphosis, and prevent further collapse and graft failure.     

An uncommon cause of paraplegia: Salmonella spondylodiskitis

BACKGROUND/OBJECTIVE: Salmonella spondylodiskitis is an uncommon type of vertebral infection. The aim of this study was to present a case of progressive paraplegia caused by Salmonella spondylodiskitis and epidural abscess after endoscopic cholecystectomy. METHODS: The patient underwent posterior instrumentation and posterior fusion between T6 and T12, hemilaminotomies at levels T8-T9-T10, and drainage of the abscess. Through a left thoracotomy, anterior T8-T10 corpectomy, debridement, anterior stabilization, and fusion were conducted. RESULTS: Fifteen months later, final follow-up showed no complications secondary to the vertebral and hip surgeries, and neurological status improved to Frankel grade E. Laboratory investigations showed no evidence of Salmonella infection. CONCLUSION: Immunocompromised patients who undergo endoscopic intervention are vulnerable to Salmonella infections. One must consider Salmonella infection in those who develop acute progressive spondylodiskitis.     

Modified hybrid fixator for high-energy Schatzker V and VI tibial plateau fractures

High-energy tibial plateau fractures associated with severe soft tissue injury are difficult to manage. The risk of wound complications following open reduction and internal fixation is notably high owing to extensive soft tissue dissection. Alternatively, application of hybrid external fixator minimizes soft tissue dissection and provides adequate fracture stabilization to allow early range of motion and correction of any mal-alignment. With this technique, soft tissue complications particularly surgical site infections are expected to be significantly reduced. This prospective study aims to determine the effectiveness of a modified hybrid external fixator in the management of high-energy tibial plateau fractures. Thirty-three patients with high-energy Schatzker V and VI tibial plateau fracture with severe soft tissue injury precluding formal open reduction were enrolled into the study. The fixator was a construct combining the Ilizarov ring with a monolateral external fixator. The results—bony union, range of motion, and associated complications of the treatment—were assessed. All fractures united within an average time of 14 weeks. Neither loss of reduction nor surgical site wound breakdown/osteomyelitis was noted. Eight patients developed superficial pin track infection and one septic arthritis of the knee joint. Hybrid external fixation is a safe option for complex high-energy tibial plateau fractures by simultaneously providing adequate fracture stabilization and protection of soft tissue healing to achieve bony union. The complication is mainly related to pin tract infection.