Bone-muscle strength indices for the human lower leg

This cross-sectional study is based on images from the lower leg as assessed by peripheral quantitative computer tomography (pQCT). Measurements were performed in 39 female and 38 male control subjects and 15 female professional volleyball players, all between 18 and 30 years of age. The images were obtained at shank levels of 4%, 14%, 33%, and 66% from the distal end. Bone and muscle cross-sectional areas, and the bones' density-weighted area moment of resistance and of inertia were assessed. From these, muscle-bone strength indices (MBSIs) were developed for compression (CI = 100. bone area/muscle area) and bending (BI = 100. bone area moment of resistance/muscle area/tibia length). Significant correlations between muscle cross-sectional area and bone were found at all section levels investigated. The strongest correlation for compression was observed in the sections at 14% (correlation coefficient r = 0.74), where 4.10 +/- 0.46 cm(2) bone, on average, was related to 100 cm(2) muscle. The compression index (CI) at the 14% level was independent of the tibia length. Interestingly, the 15 athletes had significantly greater CIs than the control subjects. This is most probably due to the greater tension development in the athletes. The highest correlation for bending was for anteroposterior bending at 33% of tibia length (r = 0.81), where the area moment of resistance, R, was on, average, 4.21 +/- 0.54 cm(3)/100 cm(2) muscle/m tibia length. Analysis of the bones' area moment of inertia showed that buckling is a possible cause of bending at the 33% and 66% levels, but not at the 14% level. No gender differences in MBSI were found. Likewise, age was without significant effect. The data show that bone architecture depends critically on muscle cross section and tension development. Moreover, bone geometry (e.g., the tibia length) influences the geometrical distribution of bone mineral, as it was found that long bones adapted to the same compressive strength are wider than short ones. We conclude that MBSIs offer a powerful diagnostic tool for bone disorders and may contribute to improving the treatment of bone metabolic and other diseases.

Age- and sex-specific differences in the 1H-spectrum of vertebral bone marrow

Correct interpretation of 1H magnetic resonance (MR) studies of the red vertebral bone marrow in patients with disorders of the hematopoietic system requires knowledge of the dependence of the proton spectrum on age and sex. Infiltration of malignant cells causes a decreased red bone marrow fat signal, which is reversed upon successful treatment. The aim of this study was to establish a database of normal water/fat relations from a large group of volunteers. In all, 154 healthy volunteers from 11 to 95 years of age were examined using a 1.5-T MR system (ACS-NT, Philips). A volume of 2-8 ml in the center of a normal vertebral body was selected for spectroscopy using the PRESS sequence without water suppression (TR/TE 2 sec/40 msec). Signal intensities and T2 times of lipid and water resonances were determined. The relative fat signal intensity was calculated corrected for T2 relaxation. The relative proportion of protons in the fat signal increases with age from 24% in the age group 11-20 years to 54% in the group > or = 61 years. The proportion of fat in the vertebral bone marrow in female subjects is less than that in male subjects in the same age group (statistically significant at P < or = 0.01). In the central age group between 31 and 50 years, the difference is largest, at 12%; in the youngest and oldest age group this difference is small. T2 times are neither age nor sex dependent.

Positional cloning of a gene for nematode resistance in sugar beet

The Hs1(pro-1) locus confers resistance to the beet cyst nematode (Heterodera schachtii Schmidt), a major pest in the cultivation of sugar beet (Beta vulgaris L.). The Hs1(pro-1) gene was cloned with the use of genome-specific satellite markers and chromosomal break-point analysis. Expression of the corresponding complementary DNA in a susceptible sugar beet conferred resistance to infection with the beet cyst nematode. The native Hs1(pro-1) gene, expressed in roots, encodes a 282-amino acid protein with imperfect leucine-rich repeats and a putative membrane-spanning segment, features similar to those of disease resistance genes previously cloned from higher plants.

Insight into protein structure and protein-ligand recognition by Fourier transform infrared spectroscopy

An overview of the application of Fourier transform infrared spectroscopy for the analysis of the structure of proteins and protein-ligand recognition is given. The principle of the technique and of the spectra analysis is demonstrated. Spectral signal assignments to vibrational modes of the peptide chromophore, amino acid side chains, cofactors and metal ligands are summarized. Several examples for protein-ligand recognition are discussed. A particular focus is heme proteins and, as an example, studies of cytochrome P450 are reviewed. Fourier transform infrared spectroscopy in combination with the various techniques such as time-resolved and low-temperature methods, site-directed mutagenesis and isotope labeling is a helpful approach to studying protein-ligand recognition.

Synthetic superoxide dismutase/catalase mimetics reduce oxidative stress and prolong survival in a mouse amyotrophic lateral sclerosis model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that causes motoneuron degeneration, paralysis and death. Mutations in Cu, Zn superoxide dismutase (SOD1) are one cause of this disease. It is widely suspected that increased reactive oxidative species (ROS) is involved in motoneuron degeneration but whether such an involvement plays a role in ALS progression in vivo is uncertain. We treated mice expressing human mutant SOD1 G93A with EUK-8 and EUK-134, two synthetic SOD/catalase mimetics that have shown efficacy in several animal models of human diseases. These treatments reduced levels of oxidative stress and prolonged survival. The results suggest that oxidative stress plays an active role in ALS and illustrate the potential for treatment strategies aimed specifically against ROS.

Direct thrombus retrieval using the reperfusion catheter of the penumbra system: forced-suction thrombectomy in acute ischemic stroke

BACKGROUND AND PURPOSE

Although the PS has been the most promising mechanical thrombectomy device in terms of recanalization rates, even the PS cannot recanalize all cases of occlusion. Under such circumstances, we simply modified the PS, identified certain advantages, and applied this modification as a primary technique for recanalization. Here we describe and discuss the technical details and results of our preliminary experience.

MATERIALS AND METHODS

This study included 22 consecutive patients with acute ischemic stroke secondary to large-artery occlusion who underwent modified thrombectomy by using the PS for recanalization. Direct wedging between the tip of the reperfusion catheter and the proximal part of the clot followed by forceful suction by using a 20- or 50-mL syringe is a unique feature of this technique. What is distinctive is that this does not require use of a separator or aspiration pump.

RESULTS

All treated vessels (100%) were successfully recanalized. A TICI scale of 2b or 3 was achieved in 81.9% of patients. A 3-month favorable functional outcome (mRS score, 0-2) was achieved in 45.5% of patients. The only procedural complication was a transient dissection of the proximal ICA, which developed while advancing the guide catheter.

CONCLUSIONS

Forced-suction thrombectomy is a simple modification of the PS. On the basis of our data, this technique allows safe and effective revascularization in acute large-vessel occlusion. Thus, for achieving the best outcome, the modified PS technique is proposed as a viable option for acute stroke management, either by itself or in conjunction with other devices or drugs.

Substrate analogue induced changes of the CO-stretching mode in the cytochrome P450cam-carbon monoxide complex

The CO-stretching mode of the carbon monoxide ligand in reduced cytochrome P450cam, in the absence or presence of camphor and in the presence of nine different camphor analogues, was measured at room temperature using Fourier transform infrared spectroscopy. Substrate-free cytochrome P450cam--CO reveals a broad, slightly structured band resulting from an overlap of several stretching mode signals. The multitude of the signals indicates that cytochrome P450 exists in a dynamic equilibrium of several conformational substates. Binding of camphor or camphor analogues strongly influences this equilibrium. For substrate analogues which are not able to form a hydrogen bond to the hydroxyl group of tyrosine 96, the CO-stretching band is rather broad and asymmetric. In contrast, substrate analogues with one quinone group which form a hydrogen bond to the Tyr96 OH induce a shift and a sharpening of the CO-stretching mode band. For substrate analogues with two hetero groups, the infrared spectrum is slightly asymmetric or a minor band appears. Sterical hindrance, substrate mobility, and protein flexibility finally determine the position and width of the CO-stretching mode signals.

Arabinogalactan for hepatic drug delivery

Arabinogalactan, a polysaccharide from the tree Larix occidentalis, has been purified and its biological and physical properties described. Intravenous injection of radiolabeled arabinogalactan (4 mg/kg) in rats resulted in 52.5% of the dose being present in the liver, while prior injection of asialofetuin (100 mg/kg) reduced hepatic radioactivity to 3.54%. Gel chromatography indicates arabinogalactan is a single species of 19 kDa, while light scattering gave a molecular weight of 40 kDa. Glycosyl linkage analysis of arabinogalactan is consistent with a highly branched structure comprising a backbone of 1,3-linked galactopyranose connected by 1,3-glycosidic linkages, comprised of 3,4,6-,3,6-, and 3,4- as well as 3-linked residues. In the carbon-13 NMR spectra, the major resonances of arabinogalactan are assigned to beta-galactopyranose, beta-arabinofuranose, and beta-arabinopyranose. Arabinogalactan produced no adverse reactions in single intravenous dose (mouse, 5000 mg/kg) and repeat dose toxicity studies (rats, 500 mg/kg/day, 90 days). When tritiated arabinogalactan was injected, radioactivity cleared from the liver with a half-life of 3.42 days. Arabinogalactan has properties that make it suitable as a carrier for delivering diagnostic or therapeutic agents to hepatocytes via the asialoglycoprotein receptor.

Phospho-dependent association of neurofilament proteins with kinesin in situ

Recent studies demonstrate co-localization of kinesin with neurofilament (NF) subunits in culture and suggest that kinesin participates in NF subunit distribution. We sought to determine whether kinesin was also associated with NF subunits in situ. Axonal transport of NF subunits in mouse optic nerve was perturbed by the microtubule (MT)-depolymerizing drug vinblastine, indicating that NF transport was dependent upon MT dynamics. Kinesin co-precipitated during immunoprecipitation of NF subunits from optic nerve. The association of NFs and kinesin was regulated by NF phosphorylation, since (1) NF subunits bearing developmentally delayed phospho-epitopes did not co-purify in a microtubule motor preparation from CNS while less phosphorylated forms did; (2) subunits bearing these phospho-epitopes were selectively not co-precipitated with kinesin; and (3) phosphorylation under cell-free conditions diminished the association of NF subunits with kinesin. The nature and extent of this association was further examined by intravitreal injection of (35)S-methionine and monitoring NF subunit transport along optic axons. As previously described by several laboratories, the wave of NF subunits underwent a progressive broadening during continued transport. The front, but not the trail, of this broadening wave of NF subunits was co-precipitated with kinesin, indicating that (1) the fastest-moving NFs were associated with kinesin, and (2) that dissociation from kinesin may foster trailing of NF subunits during continued transport. These data suggest that kinesin participates in NF axonal transport either by directly translocating NFs and/or by linking NFs to transporting MTs. Both Triton-soluble as well as cytoskeleton-associated NF subunits were co-precipitated with kinesin; these data are considered in terms of the form(s) in which NF subunits undergo axonal transport.

Measuring the indirect and direct costs of acute otitis media

OBJECTIVES

To test a method of measuring the related cost of acute otitis media (AOM) and to provide a preliminary calculation of the indirect and directs costs associated with a single, medically treated episode of AOM.

DESIGN

The Otitis Media Diary was used to measure indirect and direct costs associated with AOM in a prospective cohort study. Measured values included the parental time spent in otitis-specific child care and the number and type of medications used. A previously developed economic model was used to calculate the monetary costs associated with the value of caregiver time and the total opportunity cost of AOM.

SETTING

The pediatric clinic of Madigan Army Medical Center, Tacoma, Wash.

PATIENTS

A cohort of 25 children (12 with AOM and 13 controls) aged 1 to 3 years.

MAIN OUTCOME MEASURES

Caregiver time and medication use.

RESULTS

The total cost attributable to AOM in the 3-month period following diagnosis was $1330.58 (95% confidence interval, $1008.75-$1652.43), with the majority of that cost stemming from the indirect, rather than direct, costs of illness. After conservative estimates of unmeasured expenses, such as clinic visits and transportation, were accounted for, indirect costs, accrued primarily by parental time, accounted for nearly 90% (95% confidence interval, 87.1%-92.3%) of the total 3-month cost associated with AOM and its medical treatment. The cost items of the Otitis Media Diary were also highly correlated with each other and with other measures of clinical and functional health status.

CONCLUSIONS

Otitis Media Diary measures of parental time and medication use appear to provide a more accurate means of calculating the real social costs attributable to the AOM disease process in this cost-effectiveness analysis.

Measuring the quantity and activity of mitochondrial electron transport chain complexes in tissues of central nervous system using blue native polyacrylamide gel electrophoresis

Mitochondrial dysfunction and degeneration are associated with many neurodegenerative disorders. A dysfunctional mitochondrial electron transport chain (ETC) impairs ATP production and accelerates the generation of free radicals. To evaluate mitochondrial function, reliable methods are needed. Conventional spectrophotometric assays may not eliminate interference from nonspecific enzyme activities and do not measure quantities of specific ETC complexes. Blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used to resolve mitochondrial ETC complexes. Combined with histochemical staining, it has also been applied to measure ETC enzyme activities in muscles. The current study is to determine (1) whether BN-PAGE can be used to detect ETC complexes from different regions of the central nervous system (CNS) and (2) the quantitative range of BN-PAGE in measuring the amounts and activities of different ETC complexes. By systematically varying the protein amount and the time of histochemical reactions, we have found linear ranges comparable to spectrophotometric assays for measuring enzyme activities of several ETC complexes. In addition, we found linear ranges for measuring protein quantities in several ETC complexes. These results demonstrate that BN-PAGE can be used to measure the amount and activity of the ETC enzymes from the nerve tissues and, thus, can be applied to evaluate the functional changes of mitochondria in neurodegenerative disorders.

Polyester synthesis in transplastomic tobacco (Nicotiana tabacum L.): significant contents of polyhydroxybutyrate are associated with growth reduction

The pathway for synthesis of polyhydroxybutyrate (PHB), a polyester produced by three bacterial enzymes, was transferred to the tobacco plastid genome by the biolistic transformation method. The polycistronic phb operon encoding this biosynthetic pathway was cloned into plastome transformation vectors. Following selection and regeneration, the content and structure of plant-produced hydroxybutyrate was analysed by gas chromatography. Significant PHB synthesis was limited to the early stages of in vitro culture. Within the transformants, PHB synthesis levels were highly variable. In the early regeneration stage, single regenerates reached up to 1.7% PHB in dry weight. At least 70% of plant-produced hydroxybutyric acid was proven to be polymer with a molecular mass of up to 2,500 kDa. PHB synthesis levels of the transplastomic lines were decreasing when grown autotrophically but their phb transcription levels remained stable. Transcription of the three genes is divided into two transcripts with phbB being transcribed separately from phbC and phbA. In mature plants even low amounts of PHB were associated with male sterility. Fertility was only observed in a mutant carrying a defective phb operon. These results prove successful expression of the entire PHB pathway in plastids, concomitant, however, with growth deficiency and male sterility.

Redistribution of glycolipid raft domain components induces insulin-mimetic signaling in rat adipocytes

Caveolae and caveolin-containing detergent-insoluble glycolipid-enriched rafts (DIG) have been implicated to function as plasma membrane microcompartments or domains for the preassembly of signaling complexes, keeping them in the basal inactive state. So far, only limited in vivo evidence is available for the regulation of the interaction between caveolae-DIG and signaling components in response to extracellular stimuli. Here, we demonstrate that in isolated rat adipocytes, synthetic intracellular caveolin binding domain (CBD) peptide derived from caveolin-associated pp59(Lyn) (10 to 100 microM) or exogenous phosphoinositolglycan derived from glycosyl-phosphatidylinositol (GPI) membrane protein anchor (PIG; 1 to 10 microM) triggers the concentration-dependent release of caveolar components and the GPI-anchored protein Gce1, as well as the nonreceptor tyrosine kinases pp59(Lyn) and pp125(Fak), from interaction with caveolin (up to 45 to 85%). This dissociation, which parallels redistribution of the components from DIG to non-DIG areas of the adipocyte plasma membrane (up to 30 to 75%), is accompanied by tyrosine phosphorylation and activation of pp59(Lyn) and pp125(Fak) (up to 8- and 11-fold) but not of the insulin receptor. This correlates well to increased tyrosine phosphorylation of caveolin and the insulin receptor substrate protein 1 (up to 6- and 15-fold), as well as elevated phosphatidylinositol-3' kinase activity and glucose transport (to up to 7- and 13-fold). Insulin-mimetic signaling by both CBD peptide and PIG as well as redistribution induced by CBD peptide, but not by PIG, was blocked by synthetic intracellular caveolin scaffolding domain (CSD) peptide. These data suggest that in adipocytes a subset of signaling components is concentrated at caveolae-DIG via the interaction between their CBD and the CSD of caveolin. These inhibitory interactions are relieved by PIG. Thus, caveolae-DIG may operate as signalosomes for insulin-independent positive cross talk to metabolic insulin signaling downstream of the insulin receptor based on redistribution and accompanying activation of nonreceptor tyrosine kinases.

HOXB13 is downregulated in colorectal cancer to confer TCF4-mediated transactivation

Mutations in the Wnt signalling cascade are believed to cause aberrant proliferation of colorectal cells through T-cell factor-4 (TCF4) and its downstream growth-modulating factors. HOXB13 is exclusively expressed in prostate and colorectum. In prostate cancers, HOXB13 negatively regulates β-catenin/TCF4-mediated transactivation and subsequently inhibits cell growth. To study the role of HOXB13 in colorectal tumorigenesis, we evaluated the expression of HOXB13 in 53 colorectal tumours originated from the distal left colon to rectum with their matching normal tissues using quantitative RT–PCR analysis. Expression of HOXB13 is either lost or diminished in 26 out of 42 valid tumours (62%), while expression of TCF4 RNA is not correlated with HOXB13 expression. TCF4 promoter analysis showed that HOXB13 does not regulate TCF4 at the transcriptional level. However, HOXB13 downregulated the expression of TCF4 and its target gene, c-myc, at the protein level and consequently inhibited β-catenin/TCF-mediated signalling. Functionally, forced expression of HOXB13 drove colorectal cancer (CRC) cells into growth suppression. This is the first description of the downregulation of HOXB13 in CRC and its mechanism of action is mediated through the regulation of TCF4 protein stability. Our results suggest that loss of HOXB13 may be an important event for colorectal cell transformation, considering that over 90% of colorectal tumours retain mutations in the APC/β-catenin pathway.

Clay-bridged electron transfer between cytochrome p450(cam) and electrode

We demonstrate a very fast heterogeneous redox reaction of substrate-free cytochrome P450(cam) on a glassy carbon electrode modified with sodium montmorillonite. The linear relationship of the peak current in the cyclic voltammogram with the scan rate indicates a reversible one-electron transfer surface process. The electron transfer rate is in the range from 5 to 152 s(-1) with scan rates from 0.4 to 12 V/s, respectively. These values are comparable to rates reported for the natural electron transfer from putidaredoxin to P450(cam). The formal potential of adsorbed P450(cam) is -139 mV (vs NHE) and therefore positively shifted by 164 mV compared to the potential of substrate-free P450(cam) in solution. UV-VIS and FTIR spectra do not indicate an influence of the clay colloidal particles on the heme and the secondary structure of P450(cam) in solution. However, P450(cam) adsorbed on the surface of the clay-modified electrode may undergo partial dehydration resulting in the shift of the formal potential.

Cation metabolism in relation to cell size in synchronously grown tissue culture cell

In randomly grown tissue culture cells (mouse leukemic lymphoblast, L5178Y) the number, volume, and Na(+) and K(+) content increase as an exponential function with a doubling time of 11.3 hr. In synchronously grown cells the volume increase of the population and of single cells follows the same exponential function as in randomly grown cells. In contrast, the cation content fluctuates during a single cell cycle. About 1(1/2) hr after the cell division burst (at the beginning of the S period), a net loss of K(+) occurs for a period of about 1 hr amounting to about 20% of the total K. Over the next 5 to 6 hr, the deficit in K(+) is eliminated. The Na(+) content shows a double fluctuation. It falls during the cell division burst, rises when the K(+) content decreases, falls again when K(+) content rises, and then increases again before the next cell division burst. The net fluxes of both Na(+) and K(+) are very small compared to the unidirectional fluxes (less than 5%), thus small changes in the balance of influx and efflux account for the changes in cation content during the growth cycle. Both unidirectional fluxes increase dramatically (by a factor of two) about 2 hr after the cell division burst, and then remain constant until after the next cell division. The pattern of electrolyte regulation during cell division does not follow a simple function such as cell number, cell surface, or cell volume, but must be related to specific internal events in the cell.

Introgression of genomic components from Chinese Brassica rapa contributes to widening the genetic diversity in rapeseed (B. napus L.), with emphasis on the evolution of Chinese rapeseed

In spite of its short history of being an oil crop in China, the Chinese semi-winter rapeseed (Brassica napus L., 2n = 38, AACC) has been improved rapidly by intentional introgression of genomic components from Chinese B. rapa (2n = 20, AA). As a result, the Chinese semi-winter rapeseed has diversified genetically from the spring and winter rapeseed grown in the other regions such as Europe and North America. The objectives of this study were to investigate the roles of the introgression of the genomic components from the Chinese B. rapa in widening the genetic diversity of rapeseed and to verify the role of this introgression in the evolution of the Chinese rapeseed. Ten lines of the new type of rapeseed, which were produced by introgression of Chinese B. rapa to Chinese normal rapeseed, were compared for genetic diversity using amplified fragment length polymorphism (AFLP) with three groups of 35 lines of the normal rapeseed, including 9 semi-winter rapeseed lines from China, 9 winter rapeseed lines from Europe and 17 spring rapeseed lines from Northern Europe, Canada and Australia. Analysis of 799 polymorphic fragments revealed that within the groups, the new type rapeseed had the highest genetic diversity, followed by the semi-winter normal rapeseed from China. Spring and winter rapeseed had the lowest genetic diversity. Among the groups, the new type rapeseed group had the largest average genetic distance to the other three groups. Principal component analysis and cluster analysis, however, could not separate the new type rapeseed group from Chinese normal rapeseed group. Our data suggested that the introgression of Chinese B. rapa could significantly diversify the genetic basis of the rapeseed and play an important role in the evolution of Chinese rapeseed. The use of new genetic variation for the exploitation of heterosis in Brassica hybrid breeding is discussed.

Pathways of abnormal stress-induced Ca2+ influx into dystrophic mdx cardiomyocytes

In Duchenne muscular dystrophy, deficiency of the cytoskeletal protein dystrophin leads to well-described defects in skeletal muscle, but also to dilated cardiomyopathy, accounting for about 20% of the mortality. Mechanisms leading to cardiomyocyte cell death and cardiomyopathy are not well understood. One hypothesis suggests that the lack of dystrophin leads to membrane instability during mechanical stress and to activation of Ca2+ entry pathways. Using cardiomyocytes isolated from dystrophic mdx mice we dissected the contribution of various putative Ca2+ influx pathways with pharmacological tools. Cytosolic Ca2+ and Na+ signals as well as uptake of membrane impermeant compounds were monitored with fluorescent indicators using confocal microscopy and photometry. Membrane stress was applied as moderate osmotic challenges while membrane current was quantified using the whole-cell patch-clamp technique. Our findings suggest a major contribution of two primary Ca2+ influx pathways, stretch-activated membrane channels and short-lived microruptures. Furthermore, we found evidence for a secondary Ca2+ influx pathway, the Na+-Ca2+ exchange (NCX), which in cardiac muscle has a large transport capacity. After stress it contributes to Ca2+ entry in exchange for Na+ which had previously entered via primary stress-induced pathways, representing a previously not recognized mechanism contributing to subsequent cellular damage. This complexity needs to be considered when targeting abnormal Ca2+ influx as a treatment option for dystrophy.

Spectroscopic studies of peroxyacetic acid reaction intermediates of cytochrome P450cam and chloroperoxidase

It is generally assumed that the putative compound I (cpd I) in cytochrome P450 should contain the same electron and spin distribution as is observed for cpd I of peroxidases and catalases and many synthetic cpd I analogues. In these systems one oxidation equivalent resides on the Fe(IV)=O unit (d(4), S=1) and one is located on the porphyrin (S'=1/2), constituting a magnetically coupled ferryl iron-oxo porphyrin pi-cation radical system. However, this laboratory has recently reported detection of a ferryl iron (S=1) and a tyrosyl radical (S'=1/2), via Mössbauer and EPR studies of 8 ms-reaction intermediates of substrate-free P450cam from Pseudomonas putida, prepared by a freeze-quench method using peroxyacetic acid as the oxidizing agent [Schünemann et al., FEBS Lett. 479 (2000) 149]. In the present study we show that under the same reaction conditions, but in the presence of the substrate camphor, only trace amounts of the tyrosine radical are formed and no Fe(IV) is detectable. We conclude that camphor restricts the access of the heme pocket by peroxyacetic acid. This conclusion is supported by the additional finding that binding of camphor and metyrapone inhibit heme bleaching at room temperature and longer reaction times, forming only trace amounts of 5-hydroxy-camphor, the hydroxylation product of camphor, during peroxyacetic acid oxidation. As a control we performed freeze-quench experiments with chloroperoxidase from Caldariomyces fumago using peroxyacetic acid under the identical conditions used for the substrate-free P450cam oxidations. We were able to confirm earlier findings [Rutter et al., Biochemistry 23 (1984) 6809], that an antiferromagnetically coupled Fe(IV)=O porphyrin pi-cation radical system is formed. We conclude that CPO and P450 behave differently when reacting with peracids during an 8-ms reaction time. In P450cam the formation of Fe(IV) is accompanied by the formation of a tyrosine radical, whereas in CPO Fe(IV) formation is accompanied by the formation of a porphyrin radical.

TNFSF15 polymorphisms are associated with susceptibility to inflammatory bowel disease in a new European cohort

OBJECTIVES

Inflammatory bowel disease (IBD), e.g., Crohn's disease (CD) and ulcerative colitis (UC), is a complex genetic disorder. Tumor necrosis factor (ligand) superfamily, member 15 (TNFSF15) has been previously identified as a susceptibility gene for CD in Japanese and UK cohorts. This replication study was designed in order to confirm and further validate the role of TNFSF15 in IBD.

METHODS

A total of 666 IBD families (corresponding to 2,982 relatives) with European ancestry were genotyped for the rs6478108 and rs7869487 polymorphisms, which define the main TNFSF15 haplotypes previously associated with CD. An association between the main haplotypes and CD, UC and IBD was tested using the Genehunter TDT and Unphased statistics. Caspase recruitment domain 15 (CARD15)/TNFSF15 interaction and genotype/phenotype correlations were also studied.

RESULTS

The previously reported "high-risk" haplotype (A) was associated with IBD (P=0.001) (OR=1.25 (1.05-1.50)) and CD (P=0.02) (OR=1.31 (1.03-1.67)) whereas the "protective" (B) haplotype was significantly less transmitted to IBD and CD patients. No interaction between CARD15 and TNFSF15 was detected. We also failed to define a clinical subgroup of CD patients specifically associated with TNFSF15 haplotype A.

CONCLUSIONS

This study confirms that TNFSF15 or a closely linked gene is involved in the genetic predisposition to CD.

Regulation of neurofilament axonal transport by phosphorylation in optic axons in situ

Axonal transport of neurofilament (NFs) is considered to be regulated by phosphorylation. While existing evidence for this hypothesis is compelling, supportive studies have been largely restricted to correlative evidence and/or experimental systems involving mutants. We tested this hypothesis in retinal ganglion cells of normal mice in situ by comparing subunit transport with regional phosphorylation state coupled with inhibition of phosphatases. NF subunits were radiolabeled by intravitreal injection of 35S-methionine. NF axonal transport was monitored by following the location of the peak of radiolabeled subunits immunoprecipitated from 9x1.1 mm segments of optic axons. An abrupt decline transport rate was observed between days 1 and 6, which corresponded to translocation of the peak of radiolabeled subunits from axonal segment 2 into segment 3. Notably, this is far downstream from the only caliber increase of optic axons at 150 mu from the retina. Immunoblot analysis demonstrated a unique threefold increase between segments 2 and 3 in levels of a "late-appearing" C-terminal NF-H phospho-epitope (RT97). Intravitreal injection of the phosphatase inhibitor okadaic acid increased RT97 immunoreactivity within retinas and proximal axons, and markedly decreased NF transport rate out of retinas and proximal axons. These findings provide in situ experimental evidence for regulation of NF transport by site-specific phosphorylation.