The association between callus formation, high pressures and neuropathy in diabetic foot ulceration

The presence of an ulcer beneath callus on the diabetic foot has been a well-documented and common clinical finding. We have conducted a prospective study to examine whether callus can be used to predict plantar intrinsic neuropathic diabetic foot ulcer formation. Sixty-three diabetic patients (43 male, 25 Type 1), median age 62 years (IQ range 52, 67), median diabetes duration 17 years (IQ range 8,25) participated in the study. All had neuropathy and peak plantar foot pressures (measured using a dynamic optical pedobarograph) > or = 10 kg cm-2. Calluses and previous ulcers were documented and classified. All ulcers occurring prior to and during the study were recorded, re-examination was 15.4 (range 10-22) months from baseline. Seven ulcers (6 patients) occurred during the study. Pressures were higher in the ulcer than non-ulcer sub-group (p = 0.04) with a relative risk of developing an ulcer of 4.7 for an area of elevated plantar pressure. This compares with a relative risk of 11.0 for an ulcer developing under an area of callus, and a relative risk of 56.8 for an ulcer developing on a site of previous ulceration. This study confirms that a history of previous ulceration is the highest risk factor for ulceration and demonstrates, for the first time, that the presence of plantar callus is highly predictive of subsequent ulceration. Careful history taking and examination of the foot to detect the presence of callus require no special training or equipment and callus should be recognized as a 'high risk' factor for foot ulceration.     

Visualization of renal arteries and value of color-coded duplex sonography in renal artery stenoses using an ultrasound signal enhancing agent]

OBJECTIVES: To examine whether a second-generation perfluorocarbon (PFC) blood substitute added to the cardiopulmonary bypass (CPB) prime influences complement production. DESIGN: A prospective, randomized, single-blinded, ex vivo model. SETTING: A university hospital, laboratory, and clinics. PARTICIPANTS: Ten healthy adult consented volunteer blood donors (five men, five women). INTERVENTIONS: Ex vivo closed-loop extracorporeal circuit including membrane oxygenator, tubing, and filter primed with crystalloid or crystalloid plus PFC was circulated for 1 hour with the addition of 500 mL of heparinized fresh human whole blood. MEASUREMENTS AND MAIN RESULTS: Laboratory specimens were drawn from the circuit at 10-minute intervals for 1 hour and measured for complement (C3a, Bb fragment) concentrations, blood gases, fibrinogen concentration, platelet count, and hematocrit. In the PFC group, C3a and Bb fragments were equal to or less than those in the group that received crystalloid alone. CONCLUSION: The second-generation PFC added to the prime of a CPB circuit does not independently increase complement production.     

The value of extensive lymphadenectomy in cancer of the lower esophagus and cardia

Between 1980 and 1997, 1194 patients with a malignant tumor of the lower esophagus have been observed and treated in our Institution. There were 555 patients (46.5%) presenting with squamous-cell carcinoma, 101 (8.5%), with Barrett's adenocarcinoma and 538 (45%) with cardia adenocarcinoma. Most patient underwent a transthoracic esophagectomy with esophagogastroplasty; transhiatal approach was mainly reserved to high-risk patients. Over the past two years sixty-three patients (42 with adenocarcinoma and 21 with squamous cell carcinoma) underwent enlarged mediastinal lymphadenectomy. Three patients (4.7%) died post-operatively: one sepsis, in pulmonary embolism and one myocardial infarction. Four patients (6.3%) developed pulmonary complications: no patient had recuriential palsy. Pathologic exam revealed 1342 nodes (807 thoracic and 827 abdominal). Twenty patients (31.7%) had mediastinal nodal metastases, of which 8 in the upper mediastinum. Median follow-up was 19 months (2-36 months). Seven of the sixteen patients with recurrent disease (12 systemic, 3 mediastinal and 1 anastomotic) died. The number of metastatic nodes increased with serial section and even more with immunohistochemical staining technique (from 11.7% to 13% to 15.5%, respectively). Two patients were up-staged from M0 to M1 because of peripancreatic nodal micrometastases. We conclude that enlarged mediastinal lymphadenectomy allowed to detect upper mediastinal lymph node metastases in 12.8% of patients without increasing post-operative complication rate. A longer follow-up is required to evaluate the impact on long term survival.     

Immunohistochemical localization of novel CART peptides in rat hypothalamus, pituitary and adrenal gland

CART peptide specific polyclonal antisera were raised in rabbits. The antisera were raised to CART peptide fragments that span most of the predicted CART protein. The specificity of each antisera was demonstrated by blockade of immunostaining by the immunizing peptide but not by the other CART peptide fragments. In the hypothalamus and pituitary of colchicine and noncolchicine treated rats, immunostaining was observed in cell bodies, fibers and varicosities. Clusters of cells were also stained in the adrenal medulla. It is noteworthy that cellular immunostaining was only found in areas previously shown to express CART mRNA. These findings indicate the presence of CART peptide(s) in the hypothalamus, pituitary, and adrenal gland. Furthermore, we also present evidence for the possible processing of the CART pro-peptide into smaller peptide fragments. These neuroanatomical findings suggest a role of CART peptides in hypothalamic, pituitary and adrenal function.     

A novel cardiac hormone related to A-, B- and C-type natriuretic peptides

Mechanisms acting against accumulation of volume are important in pathophysiological situations with volume and salt overload, such as congestive heart failure. Osmoregulating animals that migrate between environments with high and low salinity are ideal models for studying the defence mechanisms against volume gain. We have now cloned and sequenced from salmon (Salmo salar) a cDNA encoding a novel vasorelaxant cardiac hormone of 29 amino acids which is produced by proteolytic processing of a 148-residue preprohormone. Structural and biological results, as well as its distribution indicate that it belongs to an unrecognized family related to natriuretic peptides, perhaps representing an ancestor of ANP and BNP. We have synthesized the 29-amino acid hormone and set up a specific radioimmunoassay. The distribution of the mRNA and peptide is strictly restricted to the heart, with high levels both in the atrium and ventricle in various fish species. The hormone relaxes aortic smooth muscle derived from salmon at nanomolar concentrations. Its release from isolated perfused salmon ventricle is very sensitive to mechanical load: a 10 mmHg load induces a rapid 5-fold increase in hormone release. Our results indicate that the novel cardiac hormone has an important role in fish volume regulation. They also demonstrate that mechanical stimuli have been central to volume regulation since early evolution.     

Role of beta-turn residues in beta-hairpin formation and stability in designed peptides

The sequence RGITVNGKTYGR has been reported as part of a de novo design peptide system. This peptide folds as a beta-hairpin structure with three residues per strand and two residue turns. Asn6 side-chain, the residue in position L1 of the beta-turn, appeared to be solvent exposed, interacting only within the turn but not with the rest of the peptide. We have chosen this position as a good candidate to design mutations, based on the protein database statistical abundances, that should mainly affect the turn stability and possibly the pairing between strands. We have found that all NMR parameters, in particular the conformational shift analysis of CalphaH and the coupling constants, 3JHNalpha, correlate very well and show similar conformational features in all the turn mutant peptides. The population estimates are in reasonable agreement among the different methods used. It appears that the peptide with Asn in position L1 is the most structured peptide, followed by the one with Asp6. The next structured peptide is the one with Gly6. The least populated peptides were those with Ala6 and Ser6. We have found a strong correlation between the hairpin population, as determined from the conformational shift of CalphaH and the occurrence of the different residues at position L1 of beta-hairpins with type I' beta-turn, in the protein database. Our analysis demonstrates that this peptide system is sensitive enough to register small energy changes in the hairpin structure; therefore, it constitutes an appropriate model to quantify energy contributions, once the appropriate sheet/coil transition algorithm is developed. Comparison with the other studies indicate that the design of a specific hairpin structure must involve a sequence at the turn region favouring the desired turn type, and a sequence at the strands that avoids alternative interstrand side-chain pairings.     

The enethiolate anion reaction products of EpiD. Pka value of the enethiol side chain is lower than that of the thiol side chain of peptides

One of the steps involved in the biosynthesis of the lantibiotic epidermin is the oxidative decarboxylation reaction of peptides catalyzed by the flavoenzyme EpiD. EpiD catalyzes the formation of a (Z)-enethiol derivative from the C-terminal cysteine residue of the precursor peptide of epidermin and related peptides. The UV-visible spectra of the reaction products of EpiD are pH-dependent, indicating that the enethiol side chain is converted to an enethiolate anion. The pKa value of the enethiol group was determined to be 6.0 and is substantially lower than the pKa value of the thiol side chain of cysteine residues. The increased acid strength of the enethiol side chain compared with that of the thiol group is attributed to the resonance stabilization of the negative charge of the anion.     

The positional distribution of dioleoyl-palmitoyl glycerol influences lymph chylomicron transport, composition and size in rats

The effects of 1,3-dioleoyl-2-palmitoyl glycerol (OPO) on lymph chylomicron transport, composition and size in rats were investigated in comparison with 1,2-dioleoyl-3-palmitoyl glycerol (OOP). The OPO and OOP were prepared by enzymatic transesterification reactions. The concentrations of OPO and OOP in the preparations were 65.7 g/100 g, and the composition of fatty acids was similar for each. The OPO preparation contained triacylglycerols with 76.6% of the palmitic acid in the sn-2 position, whereas 100% of the oleic acid was esterified to the sn-2 position in the OOP preparation. Rats were infused with lipid emulsion containing 150 g/L of OPO or OOP via a stomach catheter. Lymph was collected through the mesenteric lymphatic trunk at 1-h intervals for 12 h. Collected lymph chylomicrons were analyzed for triacylglycerol, fatty acids, apolipoprotein A-I and particle size. The maximum transport rates of triacylglycerols in the OPO group were higher than those in the OOP group. The overall absorption of triacylglycerols, palmitic acid and oleic acid in the OPO group was also higher than that in the OOP group. In the chylomicrons, 60-70% of the fatty acids at the sn-2 position of the infused triacylglycerol was transported at the original position. The transport rates of dioleoyl-palmitoyl glycerol in the OPO group were higher than those in the OOP group. The transport rates of apolipoprotein A-I did not differ between groups, whereas the mean diameter of the chylomicrons in the OPO group was larger than that in the OOP group. These results indicate that OPO is absorbed and transported more effectively than OOP.     

Amoebapores, a family of membranolytic peptides from cytoplasmic granules of Entamoeba histolytica: isolation, primary structure, and pore formation in bacterial cytoplasmic membranes

Three peptides with pore-forming activity were isolated from the cytoplasmic granules of pathogenic Entamoeba histolytica by acidic extraction, gel filtration and reversed-phase high-performance liquid chromatography. Partial amino acid sequence analysis of the three active peptides revealed that the most abundant of them was amoebapore and the other two were isoforms thereof. Cloning and sequencing of genomic DNA resolved the amino acid sequence of the two newly recognized peptides. The three peptides designated amoebapores A, B and C were found to have the same molecular size but to differ markedly in their primary structure, although all six cysteine residues are conserved. Despite sequence divergence, structural implications predict for the three peptides a similar amphipathic alpha-helical conformation stabilized by disulphide bonds. All three isoforms exhibit pore-forming activity toward lipid vesicles, but they differ in their kinetics. They also are capable of perturbing the integrity of bacterial cytoplasmic membranes and thereby kill Gram-positive bacteria. The amoebapores represent a distinct family of membrane-active peptides that may function intracellularly as antimicrobial agents but may also confer cytolytic activity on the parasite.     

A role for CAP, a novel, multifunctional Src homology 3 domain-containing protein in formation of actin stress fibers and focal adhesions

c-Cbl-associated protein, CAP, was originally cloned from a 3T3-L1 adipocyte cDNA expression library using full-length c-Cbl as a bait. CAP contains a unique structure, with three adjacent Src homology-3 (SH3) domains in the COOH terminus and a region sharing significant sequence similarity with the peptide hormone sorbin. Expression of CAP in NIH-3T3 cells overexpressing the insulin receptor induced the formation of stress fibers and focal adhesions. This effect of CAP expression on the organization of the actin-based cytoskeleton was independent of the type of integrin receptors engaged with extracellular matrix, whereas membrane ruffling and decreased actin stress fibers induced by insulin were not affected by expression of CAP. Immunofluorescence microscopy demonstrated that CAP colocalized with actin stress fibers. Moreover, CAP interacted with the focal adhesion kinase, p125FAK, both in vitro and in vivo through one of the SH3 domains of CAP. The increased formation of stress fibers and focal adhesions in CAP-expressing cells was correlated with decreased tyrosine phosphorylation of p125FAK in growing cells or upon integrin-mediated cell adhesion. These results suggest that CAP may mediate signals for the formation of stress fibers and focal adhesions.     

XR-C1, a new CHO cell mutant which is defective in DNA-PKcs, is impaired in both V(D)J coding and signal joint formation

DNA-dependent protein kinase (DNA-PK) plays an important role in DNA double-strand break (DSB) repair and V(D)J recombination. We have isolated a new X-ray-sensitive CHO cell line, XR-C1, which is impaired in DSB repair and which was assigned to complementation group 7, the group that is defective in the XRCC7 / SCID ( Prkdc ) gene encoding the catalytic subunit of DNA-PK (DNA-PKcs). Consistent with this complementation analysis, XR-C1 cells lackeddetectable DNA-PKcs protein, did not display DNA-PK catalytic activity and were complemented by the introduction of a single human chromosome 8 (providing the Prkdc gene). The impact of the XR-C1 mutation on V(D)J recombination was quite different from that found in most rodent cells defective in DNA-PKcs, which are preferentially blocked in coding joint formation, whereas XR-C1 cells were defective in forming both coding and signal joints. These results suggest that DNA-PKcs is required for both coding and signal joint formation during V(D)J recombination and that the XR-C1 mutant cell line may prove to be a useful tool in understanding this pathway.     

The effects of melanocortin peptides and corticosterone on habituation in the great plains toad, Bufo cognatus

Four patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency are presented. Clinical onset in the form of acute encephalopathy occurred between the ages of 9 months and 3 years. The clinical course included recurrent metabolic crises in 4 patients, cardiac involvement and retinopathy in 3, and myopathy in 2. None had signs of peripheral neuropathy. Three patients died and one is currently well. Hypoketotic hypoglycemia with C6-C14 3-hydroxy-dicarboxylic aciduria during metabolic crises associated with decreased plasma carnitine levels was the main biochemical finding. Enzymologic studies disclosed long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency in all patients. Homozygosity for a G to C mutation at position 1528 in the encoding region of the enzyme was found in 2 patients. Histologic and electron microscopic studies of liver biopsy specimens revealed steatosis in 3 patients and mitochondrial abnormalities in 2. Skeletal muscle biopsies disclosed nonspecific degenerative changes in 2 patients and were normal in the remaining 2. Ultrastructural abnormalities in mitochondria were found in 3 patients. A review of the literature combined with the data from our series (total 22 patients) disclosed acute clinical onset in 77% of cases and subacute in 23%. In the combined series, the average age at onset was 11 months, family history was positive in 32% of patients and overall mortality was 50%. We describe the clinical spectrum of this disease and emphasize that, among patients with suspected beta-oxidation defects the finding of pigmentary retinopathy should lead to the suspicion of long-chain 3-hydroxyacyl-coenzyme A-dehydrogenase deficiency.     

PAK4, a novel effector for Cdc42Hs, is implicated in the reorganization of the actin cytoskeleton and in the formation of filopodia

The GTPases Rac and Cdc42Hs control diverse cellular functions. In addition to being mediators of intracellular signaling cascades, they have important roles in cell morphogenesis and mitogenesis. We have identified a novel PAK-related kinase, PAK4, as a new effector molecule for Cdc42Hs. PAK4 interacts only with the activated form of Cdc42Hs through its GTPase-binding domain (GBD). Co-expression of PAK4 and the constitutively active Cdc42HsV12 causes the redistribution of PAK4 to the brefeldin A-sensitive compartment of the Golgi membrane and the subsequent induction of filopodia and actin polymerization. Importantly, the reorganization of the actin cytoskeleton is dependent on PAK4 kinase activity and on its interaction with Cdc42Hs. Thus, unlike other members of the PAK family, PAK4 provides a novel link between Cdc42Hs and the actin cytoskeleton. The cellular locations of PAK4 and Cdc42Hs suggest a role for the Golgi in cell morphogenesis.     

The kidney in chronic liver disease: circulatory abnormalities, renal sodium handling and role of natriuretic peptides

Patients with chronic liver disease (L?ennec's cirrhosis) present sodium chloride retention, leading to fluid accumulation within the extracellular space (edema) and specially in the abdomen (ascites). This article reviews the pathogenesis of the hemodynamic abnormalities observed in these patients, particularly the hypothesis of "primary arterial vasodilation", with an increased nitric oxide production by endothelial cells playing a major role in the pathogenesis of vasodilation. Since excessive renal sodium reabsorption precedes ascites formation, two hypotheses are analyzed with respect to the handling of renal sodium in chronic liver disease: the underfilling and overflow theories. Furthermore, the role of natriuretic peptides is reviewed, the increment in atrial natriuretic peptide observed in well compensated cirrhotic patients being considered as a compensatory response to volume expansion, although with renal resistance to this peptide in early stages of the disease. This review ends with an integrated explanation of the circulatory disturbances, renal sodium retention and renal resistance to atrial natriuretic peptide resulting in the sodium and water abnormalities observed in chronic liver disease.     

The expression, origin and function of tenascin during peripheral nerve formation in the chick

During development of the peripheral nervous system, the extracellular matrix molecule tenascin has been found to be closely associated with growing axons. However, its origin and function in peripheral nerve formation are far from clear. In this study, we examined the expression of tenascin during outgrowth of sensory, motor and sympathetic preganglionic axons, and assessed its origin and function in peripheral nerve formation. During outgrowth of sensory and motor axons, a high concentration of tenascin and its mRNA was found to surround sensory and motor axons in the newly formed spinal nerves. The source of this tenascin was examined through a series of surgical manipulations. Neural crest removals did not alter the distribution of tenascin protein or its mRNA surrounding the spinal nerves. Transplantation of quail somites into chick embryos showed that, similar to the distribution of tenascin, there is a high concentration of somitic cells surrounding the spinal nerves. Moreover, somite removals resulted in a reduction of the tenascin and tenascin mRNA surrounding the spinal nerves. Taken together, these results suggest that the majority of the tenascin surrounding the spinal nerves is of somitic origin. Possible functions of tenascin associated with peripheral nerve formation were examined through injections of tenascin or its antiserum into individual somites prior to or during axon outgrowth. Injections of tenascin or its antiserum did not alter the trajectory of peripheral axons in the anterior half of the somite, nor produce gross abnormalities in the morphology of peripheral nerves, suggesting that tenascin does not play a crucial role in the early formation of peripheral nerves.     

The balance of storage and computation in morphological processing: The role of word formation type, affixal homonymy, and productivity.

This article is concerned with the way in which the balance of storage—storing and processing words through full-form representations—and computation—storing and processing words through morpheme-based representations—in lexical processing in the visual modality is affected by the following 3 factors: word formation type (roughly, inflection vs. derivation), productivity, and affixal homonymy. Experimental results for 5 different Dutch suffixes, combined with previous results obtained for 4 comparable Finnish suffixes (R. Bertram, M. Laine, & K. Karvinen, 1999) and 2 Dutch suffixes (R. H. Baayen, T. Dijkstra, & R. Schreuder, 1997), show that none of these factors in isolation is a reliable cross-linguistic predictor of the balance of storage and computation. The authors offer a general framework that outlines how morphological processing is influenced by the interaction of word formation type, productivity, and affixal homonymy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, cardiac proenkephalin mRNA and enkephalin peptides in the Fisher 344 rat

Cardiac proenkephalin (PENK) mRNA, methionine-enkephalin (ME) and leucine-enkephalin (LE) were determined from 2 days of age through senescence in Fisher 344 rats. Tissues were collected at 2 days, 2 weeks, 1, 2, 3, 7, 19, and either 22 or 27 months of age. Hearts were dissected, extracted and assayed for ME and LE by radioimmunoassay (RIA) or for PENK mRNA by Northern blot analysis with a cDNA probe. Relative left ventricular (LV) PENK mRNA was low in 2 day animals and increased slowly between 2 weeks and 3 months of age. LV PENK mRNA then rose five to six-fold between 3 and 27 months of age. LV ME measurements were high in neonatal animals, declined to a nadir during development and then rose again as the animals matured and advanced in age. The pattern for right ventricular (RV) ME was similar. Atrial ME, also high at 2 days, declined thereafter and remained low. LE measurements in LV, RV and the atria followed patterns similar to those described for ME. To evaluate for peptides contributed by cardiac nerves, 3, 7 and 22-month-old animals were acutely sympathectomized for 24 h with 6-hydroxydopamine. No decline in LV ME and LE was observed in the 6-hydroxydopamine treated animals. These data suggest several conclusions regarding myocardial enkephalinergic systems: (a) tissue enkephalin and PENK mRNA increase with advancing age, (b) tissue enkephalins may not strictly correlate with the relative abundance of PENK mRNA, and (c) most myocardial enkephalins are non-adrenergic in origin. The age-associated patterns in both PENK mRNA, ME and LE suggest that physiological, maturational or behavioral events between 3 and 7 months of age initiate the up-regulation and subsequent expansion of cardiac enkephalinergic systems.