Preoperative high-frequency duplex scanning of potential pedal target vessels

OBJECTIVE

The aim of this prospective study conducted at a tertiary referral center was to evaluate the efficacy of high-frequency duplex scanning in the preoperative evaluation of potential pedal target vessels. Material and methods The study population consisted of thirty-three consecutive diabetics suffering critical limb ischemia, with indications of infra-popliteal occlusive disease. Duplex ultrasound was performed by an angiologist unaware of any prior imaging procedures. The pedal vessels were divided into four segments. The inner diameter-, the grade of calcification (on a scale from 1-to-3), the maximal systolic velocity, and the resistance index ([V.max syst-V min syst]/V max syst), were assessed by using a 13-MHz probe, and the pedal target vessel best suited for surgery was identified. Results of duplex scanning were compared to (1) the results of selective digital subtraction angiography (DSA) and contrast-enhanced magnetic resonance angiography (CE-MRA) studies interpreted by two radiologists, (2) the site of distal anastomosis predicted by a vascular surgeon according to DSA and CE-MRA studies, (3) the definitive site of distal anastomosis, and (4) early postoperative results (patency at three months).

RESULTS

Duplex scanning depicted significantly more pedal vascular segments than selective DSA- (P =.004, McNemar test). Agreement in predicting the site of distal anastomosis expressed as kappa value as follows: duplex versus DSA/CE-MRA, kappa 0.71;-DSA/CE-MRA versus definitive anastomosis, kappa 0.67; -and duplex versus definitive anastomosis kappa 0.82. Two patients were excluded from surgery as all three imaging modalities failed to demonstrate a pedal target vessel. Two patients had exploratory dissection of a pedal vessel (according to CE-MRA findings) that turned out to be occluded (as predicted by duplex scanning). In one patient the operation had to be terminated due to lack of autologous bypass material. In 31 patients who underwent pedal artery bypass, the resistance index could not be correlated to the run-off as assessed by intra-operative angiography.

CONCLUSIONS

High-frequency duplex focusing on the vacular-morphology is a worthwhile diagnostic tool to evaluate-potential pedal target vessels and extremely helpful when contrast-related methods (selective DSA, CE-MRA) do not sufficiently depict the pedal vasculature.

Detection of endocrine-modulating effects of the antithyroid acting drug 6-propyl-2-thiouracil in rats, based on the “Enhanced OECD Test Guideline 407”

The antithyroid acting drug propylthiouracil (PTU) was administered to male and female Wistar rats at 0, 0.1, 1, or 10mg/kg body weight for 4 weeks according to the draft protocol of the "Enhanced OECD Test Guideline 407" (enhanced TG 407) in order to investigate its suitability to detect endocrine-mediated effects. The study was conducted with two identical subsets of five animals per sex and dose each to provide data on sensitivity. The modified protocol includes the investigation of additional organ weights, pathology, and histopathology, of thyroid hormones, of spermatozoa, and of estrus cycle. At time of sacrifice, all females were in the diestrus stage as prescribed. Adverse effects were observed in the thyroid gland (hypertrophy/ hyperplasia) and the pituitary gland (hyperplasia of basophilic cells, hypoplasia of acidophilic cells) together with dose-related decreased serum triiodothyronine (T3) and thyroxine (T4) levels and increased thyroid stimulating hormone (TSH) levels. Other effects of PTU included decrease of organ weights, anaemia, impaired blood coagulation, and reduced activity of enzymes. Hence, some of the additional examined endpoints of the enhanced TG 407, e.g., examination of pituitary gland and thyroid hormones, were suitable to detect endocrine-modulating effects of propylthiouracil. Treatment of five animals provides sufficient sensitivity to detect the described adverse effects of propylthiouracil. The enhanced TG is currently under investigation in several laboratories, evaluation of all the results will allow determining its practicability as well as the most suitable additional endpoints.

Emergency Pedal Artery Bypass Grafting

OBJECTIVES

To determine the value of emergency pedal artery bypass.

MATERIAL AND METHODS

Data were drawn from a prospective vascular database. Inclusion criteria were: acute onset of critical forefoot ischemia, emergency surgery, no pre-operative angiographic imaging of the pedal vasculature and attempted revascularisation of a pedal vessel. Follow-up was obtained from outpatient records. The grafts were considered patent if a pedal pulse was palpable.

RESULTS

Eight out of 208 pedal vascular procedures performed between January 1996 and June 2002 were entered into the study. This cohort consisted of 3 women and 5 men (age 23-85 years, median 71). Operations were performed because of thrombo-embolic occlusion of the tibial vasculature (5 patients), severe tibial embolism following a percutaneous angioplasty of the superficial femoral artery, trash foot following aortic reconstruction and acute occlusion of tibial run-off vessels following a crural reconstruction. Two patients suffered an early graft occlusion, one of them resulting in major amputation. At a median follow up of 17 months (10-52 months) the remaining 6 grafts were patent.

CONCLUSIONS

If catheter directed methods (local lysis, aspiration embolectomy) or surgical procedures (embolectomy, tibial bypass) fail to treat critical foot ischemia, pedal probatorial dissection and pedal bypass is worthwhile.

The LPS receptor (CD14) links innate immunity with Alzheimer's disease

To rapidly respond to invading microorganisms, humans call on their innate immune system. This occurs by microbe-detecting receptors, such as CD14, that activate immune cells to eliminate the pathogens. Here, we link the lipopolysaccharide receptor CD14 with Alzheimer's disease, a severe neurodegenerative disease resulting in dementia. We demonstrate that this key innate immunity receptor interacts with fibrils of Alzheimer amyloid peptide. Neutralization with antibodies against CD14 and genetic deficiency for this receptor significantly reduced amyloid peptide induced microglial activation and microglial toxicity. The observation of strongly enhanced microglial expression of the LPS receptor in brains of animal models of Alzheimer's disease indicates a clinical relevance of these findings. These data suggest that CD14 may significantly contribute to the overall neuroinflammatory response to amyloid peptide, highlighting the possibility that the enormous progress currently being made in the field of innate immunity could be extended to research on Alzheimer's disease.

False aneurysm after balloon dilation of a calcified innominate artery stenosis

PURPOSE

To describe the occurrence of a false aneurysm after percutaneous transluminal angioplasty of a severely calcified, high-grade stenosis of the brachiocephalic trunk.

CASE REPORT

A 68-year-old patient was admitted with cerebrovascular insufficiency, right upper extremity ischemia, and recurrent amaurosis fugax. Magnetic resonance arteriography (MRA) and duplex ultrasound revealed a severely calcified, high-grade stenosis of the innominate artery. Balloon dilation of this lesion was performed with minimal morphological success. After dilation, the patient suffered a reversible ischemic neurological deficit, from which he recovered completely. The patient's symptoms improved, but after 3 weeks he was re-admitted with palsy of the recurrent laryngeal nerve. An MRA showed a false aneurysm at the dilation site. Open surgery was performed, and the patient received a bifurcated aorto-subclavian-carotid bypass graft. He was discharged free of his preoperative symptoms.

CONCLUSIONS

This case illustrates the potential hazards of angioplasty of severely calcified stenoses of the supra-aortic vessels.

Increased complexity of the species composition of lactic acid bacteria in human feces revealed by alternative incubation condition

Denaturing gradient gel electrophoresis (DGGE) of DNA fragments generated by PCR with primers specific for lactic acid bacteria (LAB) was applied to investigate various media and incubation conditions to recover LAB from human feces. Samples were plated on selective and nonselective media and incubated under standard condition (37 degrees C, anaerobiosis) for fecal LAB as well as alternative condition (30 degrees C, 2% O2). PCR-DGGE analyses of resuspended bacterial biomass (RBB) obtained from agar plates revealed that the species composition of the recovered LAB was affected more strongly by the incubation condition than by the used medium. It was observed that food-associated LAB, such as Lactobacillus sakei and Leuconostoc mesenteroides, hitherto not described as intestinal inhabitants, are more easily selected when the alternative incubation condition is used. Identification of randomly picked colonies grown under the alternative condition showed that L. sakei is one of the predominant food-associated LAB species, reaching counts of up to 106 CFU/g feces. Comparison of the results of bacteriological culture with those obtained by PCR-DGGE analysis of the RBB showed that investigation of RBB is a fast and reliable method to gain insight into the species composition of culturable LAB in feces.

[Is age an independent predictor of mortality in cardiac surgery as postulated in EuroScore?]

The number of "older" patients undergoing cardiac surgery is steadily increasing. In the year 2000, 37% of all patients who underwent a cardiac operation in Germany were 70 years of age or older. Looking at data form our institution, we focused on the topic, whether age on its own is an independent determinant for mortality in cardiac surgery. Data from 8769 patients who underwent cardiac surgery in our institution from January 1996 until January 2002 were analyzed. For all patients, EuroScore and the corresponding age-stripped value was calculated. All recorded postoperative complications and 30-day mortality were statistically analyzed. EuroScore as well as the age-stripped EuroScore showed a significant rise with increasing age in the total number of patients as well as in the patients, who did not die during the first 30 days after the operation. The 30 day mortality and the incidence of postoperative complications increased significantly with age. While the EuroScore showed a significant age-dependent increase in patients who died within 30 days after the operation, the age-stripped EuroScore did not reveal a significant discrepancy in mortality with respect to age. Arterial hypertension, diabetes mellitus and atrial fibrillation, parameters not mentioned in EuroScore, showed significant differences among age groups. According to univariate analysis, arterial hypertension and diabetes mellitus were significant predictors of mortality. Entered into a multivariate logistic regression analysis, only diabetes mellitus achieved statistical significance. Our data and the known age-associated functional and structural changes of different organ systems show that age integrates risk factors together. In order to limit mortality in the steadily growing number of older and multi-morbid patients undergoing cardiac surgery, exceptional emphasis has to be put on patient selection and therapeutic measures to improve preoperative status.

A new system for laser-UVA-microirradiation of living cells

Local nuclear irradiation of living cells has been used to gain insight into the dynamic changes that cell nuclei undergo in response to DNA damage. In particular, the effects of DNA double-strand breaks (DSBs), a major threat to the genomic integrity of cells, have been studied by local nuclear irradiation with ionizing radiation. This method has the disadvantage that it requires expensive equipment to generate a sufficiently high density of focused or collimated ionizing radiation. After appropriate sensitization of the cellular DNA, nuclear microirradiation with UVA can also produce DSBs. In this communication we present a semi-automatic system for laser-UVA-microirradiation based on a commercial laser scanning microscope. The system allows the convenient selection and precise irradiation of living cells, and could provide the basis for a more widespread availability of microirradiation facilities for DNA-repair research.

Evolution of classic Hodgkin lymphoma in correlation to changes in the lymphoid organ structure of vertebrates

In order to integrate evolutionary concepts into lymphoma research we mapped features of classic Hodgkin lymphoma (a disease which has been recently described to be derived from germinal center B-cells) onto a phylogenetic tree of vertebrates. Secondly, we matched the phylogenetic occurrence of classic Hodgkin lymphoma to the changes in the lymphoid organ structure during vertebrate evolution. According to our analysis, classic Hodgkin lymphoma evolved exclusively at the developmental stage of mammals. Interestingly the appearance of Hodgkin lymphoma is correlated to the evolution of germinal centers in mammals. This lends some credit to the hypothesis that genes specific to the germinal center reaction are involved in the pathogenesis of Hodgkin lymphoma. However, as evolution did not stop at the developmental stage of the mammalian stem-species, to a certain extent species with specific differences of classic Hodgkin lymphoma can be expected. One such difference is that classic Hodgkin lymphoma occurs with a significantly higher frequency in humans than in all other mammals. This could be partially due to Epstein-Barr virus (EBV) infection in approximately 40%-50% of Hodgkin disease cases, that is associated with an expression of the EBV-encoded oncogen LMP-1. In conclusion we propose that the mapping of lymphoma related characteristics onto a phylogenetic tree is a valuable new tool in lymphoma research.

Effects of statins on human cerebral cholesterol metabolism and secretion of Alzheimer amyloid peptide

Cerebral cholesterol metabolism has been linked with production of amyloid peptide (Abeta) crucial in AD. The association between use of cholesterol-lowering drugs (statins) and AD disease is currently being intensely discussed. In this case-control study on elderly nondemented subjects, the authors provide the first evidence that statins in clinically relevant dosages indeed affect cerebral cholesterol metabolism. However, these changes were not associated with altered intrathecal secretion of Alzheimer Abeta.

Determination of methylation site of DNA-methyltransferase NlaX by a hybrid method

Using a new method based on a combination of bisulfite reaction, the repair enzyme uracil-DNA glycosylase, and synthetic oligodeoxyribonucleotides, the methylation site of DNA-methyltransferase NlaX (M.NlaX) from Neisseria lactamica was established to be the inner cytosine in the double-stranded pentanucleotide recognition sequence 5'-CCNGG-3' (where N = any nucleoside). 5-Methylcytosine (m5C) type modification by M-N1aX was confirmed by the use of oligonucleotide substrates that contain 5-fluoro-2'-deoxycytidine.

Non-random radial higher-order chromatin arrangements in nuclei of diploid human cells

A quantitative comparison of higher-order chromatin arrangements was performed in human cell types with three-dimensionally (3D) preserved, differently shaped nuclei. These cell types included flat-ellipsoid nuclei of diploid amniotic fluid cells and fibroblasts and spherical nuclei of B and T lymphocytes from peripheral human blood. Fluorescence in-situ hybridization (FISH) was performed with chromosome paint probes for large (#1-5) and small (#17-20) autosomes, and for the two sex chromosomes. Other probes delineated heterochromatin blocks of numerous larger and smaller human chromosomes. Shape differences correlated with distinct differences in higher order chromatin arrangements: in the spherically shaped lymphocyte nuclei we noted the preferential positioning of the small, gene dense #17, 19 and 20 chromosome territories (CTs) in the 3D nuclear interior--typically without any apparent connection to the nuclear envelope. In contrast, CTs of the gene-poor small chromosomes #18 and Y were apparently attached at the nuclear envelope. CTs of large chromosomes were also preferentially located towards the nuclear periphery. In the ellipsoid nuclei of amniotic fluid cells and fibroblasts, all tested CTs showed attachments to the upper and/or lower part of the nuclear envelope: CTs of small chromosomes, including #18 and Y, were located towards the centre of the nuclear projection (CNP), while the large chromosomes were positioned towards the 2D nuclear rim. In contrast to these highly reproducible radial arrangements, 2D distances measured between heterochromatin blocks of homologous and heterologous CTs were strikingly variable. These results as well as CT painting let us conclude that nuclear functions in the studied cell types may not require reproducible side-by-side arrangements of specific homologous or non-homologous CTs. 3D-modelling of statistical arrangements of 46 human CTs in spherical nuclei was performed under the assumption of a linear correlation between DNA content of each chromosome and its CT volume. In a set of modelled nuclei, we noted the preferential localization of smaller CTs towards the 3D periphery and of larger CTs towards the 3D centre. This distribution is in clear contrast to the experimentally observed distribution in lymphocyte nuclei. We conclude that presently unknown factors (other than topological constraints) may play a decisive role to enforce the different radial arrangements of large and small CTs observed in ellipsoid and spherical human cell nuclei.

Arrangements of macro- and microchromosomes in chicken cells

Arrangements of chromosome territories in nuclei of chicken fibroblasts and neurons were analysed employing multicolour chromosome painting, laser confocal scanning microscopy and three-dimensional (3D) reconstruction. The chicken karyotype consists of 9 pairs of macrochromosomes and 30 pairs of microchromosomes. Although the latter represent only 23% of the chicken genome they containalmost 50% of its genes. We show that territories of microchromosomes in fibroblasts and neurons were clustered within the centre of the nucleus, while territories of the macrochromosomes were preferentially located towards the nuclear periphery. In contrast to these highly consistent radial arrangements, the relative arrangements of macrochromosome territories with respect to each other (side-by-side arrangements) were variable. A stringent radial arrangement of macro- and microchromosomes was found in mitotic cells. Replication labelling studies revealed a pattern of DNA replication similar to mammalian cell nuclei: gene dense, early replicating chromatin mostly represented by microchromosomes, was located within the nuclear interior, surrounded by a rim of late replicating chromatin. These results support the evolutionary conservation of several features of higher-order chromatin organization between mammals and birds despite the differences in their karyotypes.

Importance of a small N-terminal region in mammalian peptide transporters for substrate affinity and function

The two closely related, proton-coupled, electrogenic mammalian peptide transporters PEPT1 and PEPT2 differ substantially in substrate affinity and mode of function. The intestinal carrier PEPT1 has a lower affinity for most substrates than the isoform PEPT2 that is expressed in kidney, lung, brain and other tissues. A previous analysis of PEPT1-PEPT2 chimeras has suggested that the N-terminal half of the carrier proteins is important for substrate affinity. We constructed and analyzed new PEPT1-PEPT2 chimeras for identifying smaller segments within the N-terminal region of the transporter proteins that contribute to the kinetic properties. The first 59 or 91 amino-acid residues of PEPT1 were used to replace the corresponding region in PEPT2 leading to the chimeras CH3 and CH4, which could be analyzed when expressed in Xenopus laevis oocytes. Substrate affinities of both chimeras for the zwitterionic substrate D-Phe-Ala ranged between those that are characteristic for either PEPT1 or PEPT2, but when charged dipeptide substrates were employed, both chimeras possessed PEPT1-like affinities. The chimera CH3 carrying the N-terminal 59 amino-acid residues of PEPT1 exhibited a PEPT2-like phenotype with respect to pHout-dependency as well as to the current-voltage relationship of inward currents. In the chimera CH4 possessing the 91 amino-terminal residues of PEPT1, a pronounced alteration in the pHout-dependence was observed, with highest transport rates occurring at pH values as low as pH 4.0. Based on this analysis, we propose that the two identified aminoterminal regions in mammalian peptide carriers play an important role in determining the substrate affinity and also other characteristic features of the two transporter subtypes.

Determination of a non-methylated deoxycytidine residue in the recognition site of DNA-methyltransferases

A method for determination of a non-methylated deoxycytidine (dC) residue in the recognition site of 5-cytosine DNA-methyltransferases is suggested. The method is based on treatment of methylated DNA by sodium bisulfite and successive reaction of the thus modified DNA with a repair enzyme, uracil-DNA glycosylase. This method was successfully applied to identify NlaX methyltransferase specificity.

Conservation of methylation reprogramming in mammalian development: aberrant reprogramming in cloned embryos

Mouse embryos undergo genome-wide methylation reprogramming by demethylation in early preimplantation development, followed by remethylation thereafter. Here we show that genome-wide reprogramming is conserved in several mammalian species and ask whether it also occurs in embryos cloned with the use of highly methylated somatic donor nuclei. Normal bovine, rat, and pig zygotes showed a demethylated paternal genome, suggesting active demethylation. In bovine embryos methylation was further reduced during cleavage up to the eight-cell stage, and this reduction in methylation was followed by de novo methylation by the 16-cell stage. In cloned one-cell embryos there was a reduction in methylation consistent with active demethylation, but no further demethylation occurred subsequently. Instead, de novo methylation and nuclear reorganization of methylation patterns resembling those of differentiated cells occurred precociously in many cloned embryos. Cloned, but not normal, morulae had highly methylated nuclei in all blastomeres that resembled those of the fibroblast donor cells. Our study shows that epigenetic reprogramming occurs aberrantly in most cloned embryos; incomplete reprogramming may contribute to the low efficiency of cloning.

Characterization of the type IV restriction modification system BspLU11III from Bacillus sp. LU11

We report the characterization and cloning of the genes for an unusual type IV restriction-modification system, BspLU11III, from Bacillus sp. LU11. The system consists of two methyltransferases and one endonuclease, which also possesses methyltransferase activity. The three genes of the restriction-modification system, bsplu11IIIMa, bsplu11IIIMb and bsplu11IIIR, are closely linked and tandemly arranged. The corresponding enzymes recognize the dsDNA sequence 5'-GGGAC-3'/5'-GTCCC-3', with M.BspLU11IIIa modifying the A (underlined) of one strand and M.BspLU11IIIb the inner C (underlined) of the other strand. R.BspLU11III has both endonuclease and adenine-specific methyltransferase activities and is able to protect the DNA against cleavage by itself. In contrast to all type IV restriction-modification systems described so far, which have only one adenine-specific methyltransferase, BspLU11III is the first type IV restriction-modification system that includes two methyltransferases, one of them being cytosine specific.

An implantable neuroprosthesis for restoring bladder and bowel control to patients with spinal cord injuries: a multicenter trial

OBJECTIVE

To evaluate the safety and efficacy of an implanted neuroprosthesis for management of the neurogenic bladder and bowel in individuals with spinal cord injury (SCI).

DESIGN

Prospective study comparing bladder and bowel control before and at 3, 6, and 12 months after implantation of the neuroprosthesis.

SETTING

Six US hospitals specializing in treatment of SCI.

PATIENTS

Twenty-three neurologically stable patients with complete suprasacral SCIs.

INTERVENTION

Implantation of an externally controlled neuroprosthesis for stimulating the sacral nerves and posterior sacral rhizotomy.

MAIN OUTCOME MEASURES

Ability to urinate more than 200mL on demand and a resulting postvoid residual volume of less than 50mL.

RESULTS

At 1-year follow-up, 18 of 21 patients could urinate more than 200mL with the neuroprosthesis, and 15 of 21 had postvoid volumes less than 50mL (median, 15mL). Urinary tract infection, catheter use, reflex incontinence, anticholinergic drug use, and autonomic dysreflexia were substantially reduced. At 1-year follow-up, 15 of 17 patients reduced the time spent with bowel management.

CONCLUSIONS

Neural stimulation and posterior rhizotomy is a safe and effective method of bladder and bowel management after suprasacral SCI.