Characterization of an ammonium transport protein from the peribacteroid membrane of soybean nodules

Nitrogen-fixing bacteroids in legume root nodules are surrounded by the plant-derived peribacteroid membrane, which controls nutrient transfer between the symbionts. A nodule complementary DNA (GmSAT1) encoding an ammonium transporter has been isolated from soybean. GmSAT1 is preferentially transcribed in nodules and immunoblotting indicates that GmSAT1 is located on the peribacteroid membrane. [14C]methylammonium uptake and patch-clamp analysis of yeast expressing GmSAT1 demonstrated that it shares properties with a soybean peribacteroid membrane NH4^{+ channel described elsewhere. GmSAT1 is likely to be involved in the transfer of fixed nitrogen from the bacteroid to the host.}     

Reversing the inhibitory effect of nicotine on spinal fusion using an osteoinductive protein extract

STUDY DESIGN: The effect on spinal fusion of an osteoinductive bone protein extract in the presence of a known inhibitor of spinal fusion (systemic nicotine) was studied prospectively in an animal model of posterolateral lumbar fusion. OBJECTIVES: To evaluate the ability of a bovine-derived osteoinductive bone protein extract to overcome the inhibitory effect of nicotine in a rabbit spine fusion model. SUMMARY OF BACKGROUND DATA: Multiple studies have demonstrated the ability of a variety of osteoinductive growth factors to serve as a bone graft substitute for lumbar spinal fusion under "normal" healing conditions. METHODS: Forty-eight adult female New Zealand white rabbits underwent spine arthrodesis at L5-L6 while receiving systemic nicotine through a subcutaneous miniosmotic pump. Arthrodesis was performed using one of the following three graft materials: 1) autogenous iliac crest, 2) osteoinductive bone protein delivered in an allogeneic demineralized bone matrix/ collagen carrier, or 3) osteoinductive bone protein delivered with autogenous iliac crest. Fusions were assessed by blinded manual palpation, radiography, and biomechanical testing. RESULTS: Of the 44 rabbits manually tested by blinded observers, all 14 in the osteoinductive bone protein plus autogenous iliac crest bone group had solid fusions (14 of 14), whereas the fusion rate was less in the osteoinductive bone protein plus demineralized bone matrix group (nine of 14, 64%; P = 0.02), and there were no fusions in the autogenous iliac crest only group (0 of 16, 0%; P = 0.000001). The use of osteoinductive bone protein with autogenous bone produced stronger and stiffer fusions compared with those using autogenous bone alone or osteoinductive bone protein with allograft bone. CONCLUSIONS: Cigarette smoking and nicotine are inhibitory factors in the healing of fractures and spine fusions. This study shows that the inhibitory effect of nicotine can be overcome with an osteoinductive bone growth factor in an animal model.     

Posterior tilting of the tibial component decreases femoral rollback in posterior-substituting knee replacement: a computer simulation study

The extensor tendons of the fingers and toes form part of the capsule of the interphalangeal joint and press against the proximal phalanx during flexion. Previous work on the fingers has shown that there is a "sesamoid" fibrocartilage on the deep surface of each tendon that labels immunohistochemically for a variety of glycosaminoglycans and collagens. However, we know little about the molecular composition of the tendon in the toes. This question is of special interest, because the mechanics of the interphalangeal joints differ in the upper and lower limbs-the toes balance the forefoot, distribute load during the gait cycle, and transmit the pull of larger muscles. This means that their extensor tendons are more often under higher tension than those in the fingers. Here, we report the presence of an equivalent fibrocartilage and compare its immunolabelling characteristics in all the toes. Six forefeet were removed from elderly cadavers, and the interphalangeal (IP) joints were fixed in 90% methanol. The extensor tendon and its enthesis were dissected out from the IP joint of the big toe and from the proximal interphalangeal (PIP) joint of all lesser toes, decalcified, cryosectioned, and immunolabelled with a panel of monoclonal and polyclonal antibodies for type I, II, III, and VI collagens; chondroitin 4 and 6 sulphates; and dermatan and keratan sulphate. Antibody binding was detected with the Vectastain ABC Elite avidin-biotin-peroxidase kit (Vector Laboratories, Burlingame, CA). The extensor tendon in all the toes had a metachromatic, sesamoid fibrocartilage on its deep surface that immunolabelled for all glycosaminoglycans and for type I, III, and VI collagens. Labelling for type II collagen was seen in the sesamoid fibrocartilage of all toes but was particularly characteristic of the 2nd through 5th toes. The immunolabelling patterns of the enthesis fibrocartilage were similar in all toes and to results reported previously for fingers. The normal occurrence of type II collagen in the sesamoid fibrocartilage of the 2nd through 5th toes is in contrast to our published data on the fingers. The finding can be related to the more constant loading of the tendon in the toes. The greater prominence of type II collagen in the sesamoid fibrocartilage of the 2nd through 5th toes could be related to a difference in joint position during walking between the 1st toe and the 2nd through 5th toes--the PIP joints of the latter are usually more flexed than the IP joint of the former.     

Bioavailability of iron in cottonseed meal, ferric sulfate, and two ferrous sulfate by-products of the galvanizing industry

BACKGROUND: The aim of this study was to compare the outcome of severe blunt trauma in children receiving prehospital care from either physician-staffed advanced life support (ALS) units, or from basic life support (BLS) units staffed by emergency medical technicians. METHODS: The records of 288 children with severe blunt trauma who required intensive care in the regional level 1 trauma center or who died from their injuries were analyzed retrospectively. Patients were excluded if resuscitation at the scene was not attempted, if the level of prehospital care was unspecified, or if arrival at the level 1 trauma center was delayed beyond 150 minutes. Seventy-two patients met the inclusion criteria of BLS-, and 49 the criteria of ALS-prehospital care. RESULTS: A reduced mortality rate (22.4% v 31.9%) was seen in the ALS group, which was more apparent in a "salvageable but high-risk" subgroup, characterized by Glasgow Coma of Scale 4 through 8, Pediatric Trauma Score of 0 through 5, and Injury Severity Score (ISS) of 25 through 49. However, a statistically significant difference was only seen when trauma severity was evaluated by the ISS. CONCLUSION: An improved outcome in children with severe blunt trauma has been demonstrated when prehospital care is provided by physician-staffed ALS units compared with BLS units.     

Prompt fragmentation of disulfide-linked peptides during matrix-assisted laser desorption ionization mass spectrometry

During the analysis of an Asp-N digest of a recombinant hematopoietic growth factor by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), we observed pseudomolecular ions corresponding to reduced forms of peptides known to be present only in single disulfide linkages. Chromatographic fractionation of the peptide digest, followed by MALDI-MS and electrospray ionization (ESI) MS, confirmed that the reduced peptides were not present in the map. Fragmentation of the disulfide-linked peptides into their reduced forms occurred upon ionization from different matrices (alpha-cyano-4-hydroxycinnamic acid,2,5-dihydroxybenzoic acid, and in some instances sinapinic acid) but only after increasing the laser fluence to above threshold. Analysis of the disulfide-linked peptide fractions by ESI-MS, before and after mixing and drying with matrix, indicated that the matrix did not cause reduction. In a low-energy tandem mass spectrometric experiment with one of the cystinyl peptides, fragmentation did not occur preferentially at the disulfide bond. The pseudomolecular ions exhibited the same m/z values by MALDI-MS as their chemically reduced counterparts, indicating that they arose due to prompt fragmentation or "in-source decay" rather than "post-source decay". This finding is important for MALDI-MS analysis of peptide maps of proteins and peptide fractions with intact disulfides.     

Human behavioral flexibility: a psychogenetic study

Forty-seven two-children families from Moscow were used in a study to assess genetic determination of behavior flexibility, which was measured by eight laboratory tests. Flexibility is regarded as a temperament trait. There was no age- or sex-specific differentiation of human behavioral flexibility. Genetic determination of indices was used as a criterion for construct validization of flexibility tests. Factor analysis produced two principal components of flexibility: "operational flexibility" and "afferent flexibility." The study showed that a considerable part of the phenotypic variability of the flexibility indices included in different factors is under approximately equal genetic control. The flexibility factors differ in their genetic determination. In the inheritance of the first factor the leading role belongs to the additive component, whereas the dominance effects are more prominent in the second factor of flexibility.     

Survival of patients with advanced urothelial cancer treated with cisplatin-based chemotherapy

The aim of the present retrospective study was to assess long-term survival after cisplatin-based chemotherapy in 398 patients with advanced urothelial transitional cell carcinoma (TCC) treated at seven international oncological units. Various combinations of cisplatin, methotrexate, vinblastine (or vincristine) and doxorubicin were used. The complete response rate according to the WHO criteria was 17%. Partial responses were obtained in 42% of the patients. The overall cancer-related 2 year and 5 year survival rates were 21% and 11% respectively. Based on multivariate analyses, a good prognosis group could be identified comprising patients with a good performance status with disease confined to lymph nodes (14%) or patients with T4b disease only. These patients had a 28% 5 year survival rate, which, in part, has to be related to post-chemotherapy consolidation treatment in patients with pelvis-confined disease (radiotherapy, 26%; total cystectomy, 11%). Fifteen patients died of chemotherapy-related complications and in 16% of the patients toxicity led to discontinuation of treatment. Modern cisplatin-based chemotherapy leads to long-term survival and cure of selected patients with advanced urothelial transitional cancer. In routine clinical practice, chemotherapy should be offered to good prognosis patients; those presenting with a good performance status and a non-metastasising T4b tumour or with metastases confined to lymph nodes. Post-chemotherapy consolidation treatment by surgery or radiotherapy should always be considered. Such chemotherapy requires oncological expertise in order to avoid unnecessary toxicity.     

Uric acid in chronic heart failure: a marker of chronic inflammation

BACKGROUND: Chronic heart failure is associated with hyperuricaemia and elevations in circulating markers of inflammation. Activation of xanthine oxidase, through free radical release, causes leukocyte and endothelial cell activation. Associations could therefore be expected between serum uric acid level, as a marker of increased xanthine oxidase activity, and markers of inflammation. We have explored these associations in patients with chronic heart failure, taking into account the hyperuricaemic effects of diuretic therapy and insulin resistance. METHODS AND RESULTS: Circulating uric acid and markers of inflammation were measured in 39 male patients with chronic heart failure and 16 healthy controls. All patients underwent a metabolic assessment, which provided a measure of insulin sensitivity (intravenous glucose tolerance tests and minimal modelling analysis). Compared to controls, patients with chronic heart failure had significantly higher levels of circulating uric acid, interleukin-6, soluble tumour necrosis factor receptor (sTNFR)-1, soluble intercellular adhesion molecule-1 (ICAM-1, all P<0.001), E-selectin and sTNFR2 (both P<0.05). In patients with chronic heart failure, serum uric acid concentrations correlated with circulating levels of sTNFR1 (r=0.74), interleukin-6 (r=0.66), sTNFR2 (r=0.63), TNFa (r=0.60) (all P<0.001), and ICAM-1 (r=0.41, P<0.01). In stepwise regression analyses, serum uric acid emerged as the strongest predictor of ICAM-1, interleukin-6, TNF, sTNFR1 and sTNFR2, independent of diuretic dose, age, body mass index, alcohol intake, serum creatinine, plasma insulin and glucose, and insulin sensitivity. CONCLUSIONS: Serum uric acid is strongly related to circulating markers of inflammation in patients with chronic heart failure. This is consistent with a role for increased xanthine oxidase activity in the inflammatory response in patients with chronic heart failure.