The lipidome of Thoroughbred racehorses before and after supramaximal exercise.

BACKGROUND: A comprehensive study of the effect of supramaximal exercise in lipid homeostasis of Thoroughbreds provides the basis for future research on the role of lipids on energy metabolism in racehorses. OBJECTIVE: To compare the plasma lipidome of Thoroughbreds before and after supramaximal exercise using an untargeted lipidomics approach. STUDY DESIGN: Pilot experimental study. METHODS: Four Thoroughbred horses were used. The maximal oxygen consumption (VO2 max ) was calculated for each horse. Horses then underwent treadmill exercise at the speed for which the oxygen requirements had been calculated to be 115% VO2 max . Plasma samples were obtained before (T0) and immediately (T1), 15 (T2) and 30 (T3) minutes post-exercise, and evaluated using liquid chromatography/mass spectrometry. Data analysis consisted of principal component analysis and one-way repeated measures analysis of variance. RESULTS: A total of 933 plasma lipids were detected. Supramaximal exercise-induced significant changes in the signal intensity of 13 lipids; all ubiquitous in the organism as major components of biological membranes or energy substrates. MAIN LIMITATIONS: A treadmill was used to replicate track conditions. Also, sample size involved only four horses and the statistical analyses failed to achieve the desired power of 80%. CONCLUSIONS: The findings in this pilot study suggest that supramaximal exercise induces changes in specific plasma lipids in Thoroughbred racehorses. While the biological significance of these findings remains to be determined, these results provide baseline information for future studies in lipidomics applied to equine exercise physiology. Further research is warranted to better understand the role of lipids on energy metabolism in Thoroughbred racehorses.

Evaluation of trabecular bone score in patients with a distal radius fracture.

We compared bone mineral density (BMD) and trabecular bone score (TBS) in postmenopausal women with a distal radius fracture older than 50 years with controls. Total hip BMD was significantly different, but TBS was not different between two groups, suggesting TBS does not reflect microarchitectural changes of the distal radius. INTRODUCTION: The purpose of this study was to determine whether trabecular bone score (TBS) has additive value for discriminating distal radius fracture (DRF) independent of BMD. METHODS: We compared BMD and TBS in 258 postmenopausal women with a DRF older than 50 years of age with age- and body mass index (BMI)-matched controls who had no history of osteoporotic fracture. BMD was measured at the lumbar spine and hip using dual energy X-ray absorptiometry scans (GE Lunar Prodigy). TBS was calculated on the same spine image. A multivariate logistic regression analysis was used to analyze the odds ratio (OR) for the occurrence of DRF using age, BMI, lumbar spine BMD, total hip BMD, and TBS. RESULTS: Patients with a DRF had significantly lower BMDs at hip (neck, trochanter and total) than those of controls: 0.752 ± 0.097, 0.622 ± 0.089, and 0.801 ± 0.099 in patients and 0.779 ± 0.092, 0.648 ± 0.089, 0.826 ± 0.101 in controls. However, lumbar spine BMD and TBS were not significantly different between the groups (p = 0.400 and 0.864, respectively). The multivariate analysis indicated that only total hip BMD was significantly associated with the occurrence of DRF (OR, 10.231; 95 % confidence interval, 1.724-60.702; p = 0.010). CONCLUSIONS: TBS was not different between women with a DRF and those without a history of osteoporotic fracture, suggesting that TBS measured at the lumbar spine does not reflect early microarchitectural changes of the distal radius. Only total hip BMD is associated with the risk of DRF in Korean women.

An investigation of the storage and biosynthesis of phenylpropenes in sweet basil.

Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.

Hepatic dysfunction as the presenting feature of acute lymphoblastic leukemia.

PURPOSE: Hepatic dysfunction is a rare presentation of leukemia in children. Because most chemotherapy agents are metabolized by the liver, this complication may have major adverse consequences and effective treatment could be compromised. PATIENTS AND METHODS: The MEDLINE database and current management guidelines from the United States Pediatric Cooperative Cancer Groups were reviewed and analyzed. Data from two institutional cases are described. RESULTS: Although previous literature is not informative, our experience suggests that children with leukemia and moderate hepatic dysfunction may tolerate aggressive chemotherapy. CONCLUSION: Current protocol guidelines for dose modification for liver disease may be overly stringent and modification may be beneficial.

Genetics and biochemistry of secondary metabolites in plants: an evolutionary perspective.

The evolution of new genes to make novel secondary compounds in plants is an ongoing process and might account for most of the differences in gene function among plant genomes. Although there are many substrates and products in plant secondary metabolism, there are only a few types of reactions. Repeated evolution is a special form of convergent evolution in which new enzymes with the same function evolve independently in separate plant lineages from a shared pool of related enzymes with similar but not identical functions. This appears to be common in secondary metabolism and might confound the assignment of gene function based on sequence information alone.

Evolution of plant defense mechanisms. Relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases.

Pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." This study establishes the first known catalytic function for the latter, as being able to engender the NADPH-dependent reduction of phenylcoumaran benzylic ethers. Accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. In this investigation, the phenylcoumaran benzylic ether reductase from the gymnosperm, Pinus taeda, was cloned, with the recombinant protein heterologously expressed in Escherichia coli. The purified enzyme reduces the benzylic ether functionalities of both dehydrodiconiferyl alcohol and dihydrodehydrodiconiferyl alcohol, with a higher affinity for the former, as measured by apparent Km and Vmax values and observed kinetic 3H-isotope effects. It abstracts the 4R-hydride of the required NADPH cofactor in a manner analogous to that of the pinoresinol-lariciresinol reductases and isoflavone reductases. A similar catalytic function was observed for the corresponding recombinant reductase whose gene was cloned from the angiosperm, Populus trichocarpa. Interestingly, both pinoresinol-lariciresinol reductases and isoflavone reductases catalyze enantiospecific conversions, whereas the phenylcoumaran benzylic ether reductase only shows regiospecific discrimination. A possible evolutionary relationship among the three reductase classes is proposed, based on the supposition that phenylcoumaran benzylic ether reductases represent the progenitors of pinoresinol-lariciresinol and isoflavone reductases.

Regiochemical control of monolignol radical coupling: a new paradigm for lignin and lignan biosynthesis.

BACKGROUND: Although the lignins and lignans, both monolignol-derived coupling products, account for nearly 30% of the organic carbon circulating in the biosphere, the biosynthetic mechanism of their formation has been poorly understood. The prevailing view has been that lignins and lignans are produced by random free-radical polymerization and coupling, respectively. This view is challenged, mechanistically, by the recent discovery of dirigent proteins that precisely determine both the regiochemical and stereoselective outcome of monolignol radical coupling. RESULTS: To understand further the regulation and control of monolignol coupling, leading to both lignan and lignin formation, we sought to clone the first genes encoding dirigent proteins from several species. The encoding genes, described here, have no sequence homology with any other protein of known function. When expressed in a heterologous system, the recombinant protein was able to confer strict regiochemical and stereochemical control on monolignol free-radical coupling. The expression in plants of dirigent proteins and proposed dirigent protein arrays in developing xylem and in other lignified tissues indicates roles for these proteins in both lignan formation and lignification. CONCLUSIONS: The first understanding of regiochemical and stereochemical control of monolignol coupling in lignan biosynthesis has been established via the participation of a new class of dirigent proteins. Immunological studies have also implicated the involvement of potential corresponding arrays of dirigent protein sites in controlling lignin biopolymer assembly.

Recombinant pinoresinol-lariciresinol reductases from western red cedar (Thuja plicata) catalyze opposite enantiospecific conversions.

Although the heartwood of woody plants represents the main source of fiber and solid wood products, essentially nothing is known about how the biological processes leading to its formation are initiated and regulated. Accordingly, a reverse transcription-polymerase chain reaction-guided cloning strategy was employed to obtain genes encoding pinoresinol-lariciresinol reductases from western red cedar (Thuja plicata) as a means to initiate the study of its heartwood formation. (+)-Pinoresinol-(+)-lariciresinol reductase from Forsythia intermedia was used as a template for primer construction for reverse transcription-polymerase chain reaction amplifications, which, when followed by homologous hybridization cloning, resulted in the isolation of two distinct classes of putative pinoresinol-lariciresinol reductase cDNA clones from western red cedar. A representative of each class was expressed as a fusion protein with beta-galactosidase and assayed for enzymatic activity. Using both deuterated and radiolabeled (+/-)-pinoresinols as substrates, it was established that each class of cDNA encoded a pinoresinol-lariciresinol reductase of different (opposite) enantiospecificity. Significantly, the protein from one class converted (+)-pinoresinol into (-)-secoisolariciresinol, whereas the other utilized the opposite (-)-enantiomer to give the corresponding (+)-form. This differential substrate specificity raises important questions about the role of each of these individual reductases in heartwood formation, such as whether they are expressed in different cells/tissues or at different stages during heartwood development.

Intrapancreatic ciliated enteric duplication cyst presenting with biliary obstruction.

A 46-yr-old man presenting with biliary obstruction from an intrapancreatic tumor underwent pancreaticoduodenectomy. The pathology report showed the tumor to be an enteric duplication cyst. Diagnostic imaging features and operative management are discussed.

(+)-Pinoresinol/(+)-lariciresinol reductase from Forsythia intermedia. Protein purification, cDNA cloning, heterologous expression and comparison to isoflavone reductase.

Lignans are a widely distributed class of natural products, whose functions and distribution suggest that they are one of the earliest forms of defense to have evolved in vascular plants; some, such as podophyllotoxin and enterodiol, have important roles in cancer chemotherapy and prevention, respectively. Entry into lignan enzymology has been gained by the approximately 3000-fold purification of two isoforms of (+)-pinoresinol/(+)-lariciresinol reductase, a pivotal branchpoint enzyme in lignan biosynthesis. Both have comparable ( approximately 34.9 kDa) molecular mass and kinetic (Vmax/Km) properties and catalyze sequential, NADPH-dependent, stereospecific, hydride transfers where the incoming hydride takes up the pro-R position. The gene encoding (+)-pinoresinol/(+)-lariciresinol reductase has been cloned and the recombinant protein heterologously expressed as a functional beta-galactosidase fusion protein. Its amino acid sequence reveals a strong homology to isoflavone reductase, a key branchpoint enzyme in isoflavonoid metabolism and primarily found in the Fabaceae (angiosperms). This is of great evolutionary significance since both lignans and isoflavonoids have comparable plant defense properties, as well as similar roles as phytoestrogens. Given that lignans are widespread from primitive plants onwards, whereas the isoflavone reductase-derived isoflavonoids are mainly restricted to the Fabaceae, it is tempting to speculate that this branch of the isoflavonoid pathway arose via evolutionary divergence from that giving the lignans.

Preparation of genomic DNA for RAPD analysis from thick-walled dormant teliospores of Tilletia species.

We describe a method for isolating genomic DNA from teliospores of Tilletia caries (DC) Tul., T. controversa Kuhn and T. foetida (T. laevis) (Wallr.) Liro. for random-amplified polymorphic DNA (RAPD) analysis. DNA analysis of teliospores of covered smut or bunt has been difficult because of the thick wall and the high lipid content of the spores. This method overcomes these problems and yields sufficient quantities of DNA from the three species' teliospores for RAPDs. DNA quality appears to be good with very little degradation. RAPD amplifications of the extracted DNAs are reproducible and produce numerous large molecular weight bands from each individual. This procedure should permit the use of DNA analysis techniques to study species and races of Tilletia as well as fungi with similar spore structure.

Seasonal variation in volatile secondary compounds ofChrysothamnus nauseosus (Pallas) britt.; asteraceae ssp.hololeucus (Gray) hall. & clem. Influences herbivory.

Chrysothamnus nauseosus (rubber rabbitbrush) is used by browsing animals, especially mule deer (Odocoileus hemionus), as a forage in the winter months. It is used only slightly, if at all in the summer. This dietary difference may result from changes in the secondary chemical composition of the leaves. Solvent extracts from summer and winter rabbitbrush leaves were analyzed by gas chromatography and mass spectrometry, and the volatile compounds were quantified and identified. Hexane and chloroform extracts from winter leaves exhibit a marked concentration decrease in most chemicals when compared to summer extracts. The methanol extracts revealed the presence of several chemicals in the summer leaves that were absent in winter leaves. Rubber rabbitbrush has fewer secondary volatile chemicals in the winter than in the summer. These chemical differences may influence the seasonal dietary difference observed in mule deer and other browsing animals.

Melanotic neuroectodermal tumor of infancy: an important mimicker of paratesticular rhabdomyosarcoma.

We report a case of a paratesticular tumor in a 6-month-old infant. This tumor was originally believed to represent a poorly differentiated sarcoma of the cord but upon further pathological consultation it was recognized as a rare melanotic neuroectodermal tumor of infancy involving the epididymis. Since the former is a highly aggressive lesion and the latter an indolent tumor, treatment of these 2 entities differs markedly. Therefore, although the histological distinction between these lesions is often difficult, it is of critical importance.

Gastroduodenal mucosal prostaglandin generation in patients with Helicobacter pylori before and after treatment with bismuth subsalicylate.

To determine whether Helicobacter pylori has an effect on gastroduodenal mucosal prostaglandin generation, mucosal biopsies were obtained from the gastric body, antrum, and duodenal bulb of 30 patients who were undergoing upper gastrointestinal endoscopy for clinical indications. One biopsy from the gastric body and one from the antrum were tested for urease activity (urea broth) and one biopsy from each area including the duodenum was processed for histology. Two other biopsies form each area were incubated and the accumulation of prostaglandin E2 and 6-keto prostaglandin F1 alpha in the incubation medium was measured by radioimmunoassay. Twelve of the 17 H. pylori-positive patients and seven of the 13 H. pylori-negative patients agreed to take bismuth subsalicylate (Pepto-Bismol) two tablets four times a day for four weeks. One week after treatment, these patients again underwent endoscopy and the above studies. This study indicates that: (1) mucosal PGE2 generation may be increased in the duodenum, gastric body, and antrum in H. pylori-positive patients compared to H. pylori-negative patients, and (2) treatment with bismuth subsalicylate for four weeks results in reduction of mucosal PGE2 in the duodenum, gastric body, and antrum of H. pylori-positive patients and fails to eradicate H. pylori or reduce gastric inflammation.

Mesenteric oxygen metabolism, ileal mucosal hydrogen ion concentration, and tissue edema after crystalloid or colloid resuscitation in porcine endotoxic shock: comparison of Ringer's lactate and 6% hetastarch.

We performed an experimental trial comparing crystalloid (Ringer's lactate) and colloid (hetastarch) resuscitation in pentobarbital-anesthetized pigs. Superior mesenteric arterial blood flow (Qsma) was measured using an ultrasonic flow probe, and ileal intramucosal hydrogen ion concentration [( H+]I) was estimated tonometrically. Beginning at t = 0 min, all animals were infused over 20 min with Escherichia coli (0111:B4) lipopolysaccharide (LPS; 150 micrograms/kg). Starting at t = 0 min and continuing for the duration of the experiment (3 hr), pigs in group I (N = 9) were resuscitated with Ringer's lactate (1.2 ml/kg min), whereas animals in group II (n = 9) were infused with 6% hetastarch in saline (0.4 ml/kg min). Systemic and mesenteric hemodynamic changes induced by LPS were similar in both groups; mean arterial pressure and systemic vascular resistance index decreased (P less than .05), but cardiac index was well preserved. Central venous pressure increased (P less than .05). Superior mesenteric O2 delivery decreased significantly (P less than .05) in both groups, although mesenteric O2 uptake was unchanged. Ileal [H+]I increased (P less than .05) in both groups. Gravimetrically determined extravascular water was greater in lung (P = .03) and ileum (P = .058) in group I as compared to group II. Although crystalloid infusion was associated with greater tissue edema, this effect did not translate into a difference in systemic or regional (i.e., mesenteric) O2 uptake or greater ileal tissue acidosis.

Patterns of reactivity of Epstein-Barr virus-specific T cells in A-type donor cultures after reactivation with autologous A- or B-type transformants.

Regression endpoints were assessed in cultures from 11 Epstein-Barr (EB) virus A-type seropositive donors and 2 seronegative donors using A- and B-type EB virus preparations. In 9/11 of the seropositive donors, the resulting endpoints using A-type or B-type virus were similar and demonstrated a significant T cell response to both virus types. However, the regression endpoints for 2/11 seropositive donors were reproducibly higher with B-type virus compared with A-type virus, indicating a weak T cell response to the B-type virus compared with that to the A-type virus. Seronegative donor cultures showed no regression. The patterns of reactivity of bulk cultures of EB virus-specific cytotoxic T cells and T cell clones from selected seropositive donors were compared. Four of six donors showed evidence of a cytotoxic T cell response to A- and B-type autologous transformants while cytotoxic T cells from 2/6 donors (corresponding to those identified as lacking regression to B-type virus) lysed autologous targets infected with A-type but not B-type virus. The results show that while most A-type seropositive donors are capable of mounting a T cell response to A- and B-type virus, certain donors apparently lack B-type reactivity.