Mild oxidative damage in the diabetic rat heart is attenuated by glyoxalase-1 overexpression.

Diabetes significantly increases the risk of heart failure. The increase in advanced glycation endproducts (AGEs) and oxidative stress have been associated with diabetic cardiomyopathy. We recently demonstrated that there is a direct link between AGEs and oxidative stress. Therefore, the aim of the current study was to investigate if a reduction of AGEs by overexpression of the glycation precursor detoxifying enzyme glyoxalase-I (GLO-I) can prevent diabetes-induced oxidative damage, inflammation and fibrosis in the heart. Diabetes was induced in wild-type and GLO-I transgenic rats by streptozotocin. After 24-weeks of diabetes, cardiac function was monitored with ultrasound under isoflurane anesthesia. Blood was drawn and heart tissue was collected for further analysis. Analysis with UPLC-MSMS showed that the AGE Nε-(1-carboxymethyl)lysine and its precursor 3-deoxyglucosone were significantly elevated in the diabetic hearts. Markers of oxidative damage, inflammation, and fibrosis were mildly up-regulated in the heart of the diabetic rats and were attenuated by GLO-I overexpression. In this model of diabetes, these processes were not accompanied by significant changes in systolic heart function, i.e., stroke volume, fractional shortening and ejection fraction. This study shows that 24-weeks of diabetes in rats induce early signs of mild cardiac alterations as indicated by an increase of oxidative stress, inflammation and fibrosis which are mediated, at least partially, by glycation.

Telomere length and mental well-being in elderly men from the Netherlands and Greece.

Telomeres, repetitive DNA sequences that promote chromosomal stability, have been related to different measures of mental well-being and self-rated health, but mainly in women during adulthood. We aimed to investigate whether accelerated telomere shortening is associated with poor mental well-being and poor self-rated health in community-dwelling elderly men. Leukocyte telomere length was measured using quantitative PCR in two different samples of 203 elderly men (mean age 78 years) from the Netherlands in 1993, and 123 elderly men (mean age 84 years) from Greece in 2000. We also obtained follow-up data in 2000 from 144 Dutch subjects, of whom 75 had paired telomere length data in 1993 and 2000. Mental well-being was conceptualized as dispositional optimism, depressive symptoms, cognitive functioning, and loneliness. Linear regression analyses were used to study the association between telomere length, measures of mental well being, and self-rated health, while adjusting for potential confounders. In cross-sectional analyses, leukocyte telomere length was not associated with measures of mental well-being and self-rated health, neither in the Netherlands nor in Greece. Also, the rate of leukocyte telomere shortening (mean decrease: 0.28 kbp over 7 years) in the 75 Dutch participants with longitudinal data was not associated with changes in different measures of mental well-being and self-rated health. Thus, our results provide no support for a relationship between leukocyte telomere length and mental well-being in elderly community-dwelling men.

A GPS-enabled seabed sediment sampler: Recovery efficiency and efficacy.

The design, manufacture, and commissioning of a global positioning system enabled sampler instrument conceived for the retrieval of seabed sediments are described. This system was designed for sampling in environmental assessment applications and, especially, those requirements that might include insoluble, anthropogenic radioactivity derived from the effluent from nuclear facilities. Once triggered, the sampler operates autonomously for the recovery of samples by settling in the sampling environment, and it is compatible with submersion in fresh water and also with an off-the-shelf, submersible, remotely operated vehicle. A number of tests have been carried out to determine the efficiency and efficacy of the sample recovery performed by the system and the extent to which the recovery of samples disturbs neighboring sediments.

Depicting corrosion-born defects in pipelines with combined neutron/γ ray backscatter: a biomimetic approach.

The identification of corrosion, cracks and defects in pipelines used for transporting oil and gas can reduce the possibility of leaks, and consequently, it can limit the extent of an environmental disaster, public hazard and the associated financial impact of such events. Typically, corrosion in oil pipelines is measured with non-destructive ultrasonic or electromagnetic techniques, on the basis that corrosion and defects are often manifest as a change of thickness in the steel from which pipelines are made. However, such approaches are not practical for underground pipelines and their deployment can be complicated for the case of pipelines covered by insulation. In this paper, we present an innovative, non-destructive testing technique, which exploits the backscatter of a combination of fast-neutron and γ radiation from steel samples of a variety of thicknesses consistent with changes that might arise due to corrosion of a pipe wall. Our research demonstrates the potential to measure and characterise different steel thicknesses by detecting both the elastic, fast-neutron backscatter and the Compton-scattered γ radiations, simultaneously. Further, we demonstrate that the presence of insulation yields a consistent and separable influence on the experimental, wall-thickness measurements. The data from experimental measurements are supported by a comprehensive Monte Carlo computer simulation study.

Passive, non-intrusive assay of depleted uranium.

The ability to detect neutrons from the spontaneous fission of 238U in samples of depleted uranium with organic liquid scintillation detectors is presented. In this paper we introduce a small modular organic liquid scintillator detector array that can detect changes in mass of 238U between 3.69 g and 14.46 g. To do this, 18-h assays of various masses of 0.3% wt. of depleted uranium dioxide were assessed using four EJ-309 detectors, a mixed field analyser operated in pulse gradient analysis mode, and associated counting components. We observe a background-corrected fast neutron count sensitivity of (2.0 ±â€¯0.3) × 10-4 n g-1 s-1 per detector. This research demonstrates a proof of concept for depleted uranium quantity to be assessed passively on a non-intrusive basis via its spontaneous fission decay.

Telomere length assessment: biomarker of chronic oxidative stress?

Telomeres are nucleoprotein structures, located at the ends of chromosomes and are subject to shortening at each cycle of cell division. They prevent chromosomal ends from being recognized as double strand breaks and protect them from end to end fusion and degradation. Telomeres consist of stretches of repetitive DNA with a high G-C content and are reported to be highly sensitive to damage induced by oxidative stress. The resulting DNA strand breaks can be formed either directly or as an intermediate step during the repair of oxidative bases. In contrast to the majority of genomic DNA, there is evidence that telomeric DNA is deficient in the repair of single strand breaks. Since chronic oxidative stress plays a major role in the pathophysiology of several chronic inflammatory diseases, it is hypothesized that telomere length is reducing at a faster rate during oxidative stress. Therefore, assessment of telomere length might be a useful biomarker of disease progression. In this review several features of telomere length regulation, their relation with oxidative stress, and the potential application of measurement of telomere length as biomarker of chronic oxidative stress, will be discussed.

A portable energy-sensitive cosmic neutron detection instrument.

The construction and testing of a portable energy-sensitive neutron instrument are described. This instrument has been designed and constructed for the primary purpose of characterizing cosmic-ray neutron fields in the upper atmosphere and in cosmic reference field facilities. The instrument comprises a helium-3 proportional counter surrounded by 15 mm of lead and 140 mm of polyethylene creating a spherical structure with a diameter of 34 cm. The instrument also incorporates 12 boron-coated diodes, six on the outside of the polyethylene layer with six placed within the structure. The dimensions, materials, and arrangement of these in the instrument have previously been optimized with the MCNPX Monte Carlo simulation software to provide a compromise between the requirements of portability and spectral response. Testing took place at several locations and experimental data from the instrument's operation at the high-altitude Jungfraujoch laboratory in the Swiss alps are presented.

A remotely triggered fast neutron detection instrument based on a plastic organic scintillator.

A detector system for the characterization of radiation fields of both fast neutrons and γ rays is described comprising of a gated photomultiplier tube (PMT), an EJ299-33 solid organic scintillator detector, and an external trigger circuit. The objective of this development was to conceive a means by which the PMT in such a system can be actuated remotely during the high-intensity bursts of pulsed γ-ray contamination that can arise during active interrogation procedures. The system is used to detect neutrons and γ rays using established pulse-shape discrimination (PSD) techniques. The gating circuit enables the PMT to be switched off remotely. This is compatible with use during intense radiation transients to avoid saturation and the disruption of the operation of the PMT during the burst. Data are presented in the form of pulse-height spectra and PSD scatter plots for the system triggered with a strobed light source. These confirm that the gain of the system and the throughput for both triggered and un-triggered scenarios are as expected, given the duty cycle of the stimulating radiation. This demonstrates that the triggering function does not perturb the system response of the detector.

The role of glutathione in the regulation of nucleotide excision repair during oxidative stress.

Nucleotide excision repair (NER) mainly repairs bulky DNA adducts and helix distorting lesions, but is additionally considered to be a back-up system for base excision repair to remove oxidative stress induced DNA damage. Therefore, it can be speculated that NER is up-regulated or primed by oxidative stress. Exposure of human pulmonary epithelial cells (A549) to non-toxic doses of 100muM H(2)O(2) indeed showed a 2 to 4.5-fold increase in expression of XPA, XPC, ERCC4, and ERCC5, whereas the expression of ERCC1 was 5-fold decreased. Phenotypical assessment of NER capacity (i.e. recognition and incision of benzo[a]pyrene-DNA adducts) showed a significant decrease to less than 50% after H(2)O(2) exposure, which paralleled the effects of H(2)O(2) on ERCC1 expression. To study the possible involvement of glutathione (GSH) in the regulation of NER, cells were pre-incubated with 0.5mM BSO, resulting in total GSH depletion and increased intracellular oxidative stress. In GSH-depleted cells, the down-regulation of ERCC1 expression by H(2)O(2) was completely abolished and the up-regulation of ERCC4 expression was potentiated from 2.5-fold to >10-fold. Similarly, the H(2)O(2)-induced decrease in NER capacity was absent in GSH-depleted cells. Overall, our data suggest that NER capacity as well as the expression of NER related genes can be modulated by oxidative stress. ERCC1 expression and NER capacity correlated strongly (R(2)=0.85, P<0.01) after oxidant exposure, indicating ERCC1 as a specific target for oxidative stress induced modification of NER.

The design of a portable cosmic ray three-band neutron detector.

The design of a portable three-band cosmic-ray neutron detector is reported in this article. This instrument has been designed to characterise cosmic ray neutron fields in the upper atmosphere and in cosmic reference field facilities. The design utilises a spherical moderator with a layer of spallation material covering a central (3)He proportional counter. The instrument incorporates twelve lithium-coated diodes, six on the outside of the polyethylene layer and six placed within the structure. The dimensions, materials and arrangement of these in the instrument have been optimised with MCNPX to provide a compromise between the requirements of portability and spectral response.

Establishment and characterization of three new continuous cell lines derived from human breast carcinomas.

Three continuous lines of mammary tumor cells (ZR-75-1, ZR-75-27, and ZR-75-30) have been established from malignant effusions of two women with breast cancer. Differentiated properties expressed by each cell line include: (a) epithelial morphology (by light and electron microscopy) resembling that of the parental tumors; (b) presence of receptors for estrogen and other steroid hormones; and (c) growth responsiveness to estrogen and/or progesterone. All three cell lines possess human karyotypes that differ from one another in modal chromosome number as well as in characteristic marker chromosomes. Two of the cultures (ZR-75-27 and ZR-75-30), although derived from the same patient, have stable differences in their karyotypes.

Competitive inhibitors of rabbit hepatic microsomal steroid 12 alpha-hydroxylase.

The sterols 7 alpha-hydroxycholest-4-en-3-one (I) and 5 alpha-cholestane-3 alpha,7 alpha-diol (II) are competitive inhibitors for rabbit hepatic microsomal preparations of steroid 12 alpha-hydroxylase with apparent Ki values of 56 and 93 microM, respectively. To ascertain the optimum structure for a substrate with maximal enzymic activity, nine sterols or steroidal acids containing the 7 alpha-hydroxy-4-en-3-one or 3 alpha,7 alpha-dihydroxy-5 alpha configuration were prepared and studied as inhibitors with enzyme preparations in the presence of NADPH, oxygen and appropriate cofactors. Although each of these compounds exhibited competitive inhibition, the best inhibitor for sterol (I) was 7 alpha,25-dihydroxycholest-4-en-3-one (IV) (Ki 36 microM). Steroidal acids (3-oxo-7 alpha-hydroxychol-4-enoic acid and 3-oxo-7 alpha-hydroxy-4-cholene-24-carboxylic acid) were poor inhibitors (Ki 1080 and 654 microM, respectively). For sterol (II) the best inhibitors were sterol (IV) (Ki 35 microM) and 5 alpha-cholestane-3 alpha,7 alpha,25-triol (VIII) (Ki 45 microM). The 12 alpha-hydroxylated products of sterols (I) and (IV) were less tightly bound to the enzyme (Ki 88 and 98 microM, respectively) in the presence of sterol (II). Allochenodeoxycholic acid (Ki 495 microM) was not a good inhibitor for sterol (II). 12 alpha-Hydroxylated products of sterols (IV) and (VIII) were isolated from larger scale incubations, separated by HPLC and identified by mass spectrometry.

Characterisation of the TRIUMF neutron facility using a Monte Carlo simulation code.

Here, the characterisation of the high-energy neutron field at TRIUMF (The Tri Universities Meson Facility, Vancouver, British Columbia) with Monte Carlo simulation software is described. The package used is MCNPX version 2.6.0, with the neutron fluence rate determined at three locations within the TRIUMF Thermal Neutron Facility (TNF), including the exit of the neutron channel where users of the facility can test devices that may be susceptible to the effects of this form of radiation. The facility is often used to roughly emulate the field likely to be encountered at high altitudes due to radiation of galactic origin and thus the simulated information is compared with the energy spectrum calculated to be due to neutron radiation of cosmic origin at typical aircraft altitudes. The calculated values were also compared with neutron flux measurements that were estimated using the activation of various foils by the staff of the facility, showing agreement within an order of magnitude.

Dedifferentiated chondrosarcoma with rhabdomyosarcomatous differentiation.

Dedifferentiated chondrosarcomas are primary bone tumors characterized by the presence of both low-grade cartilaginous and high-grade sarcomatous components. The high-grade component usually shows histologic features of either malignant fibrous histiocytoma or fibrosarcoma. We are aware of only 10 published cases in which the high-grade component showed rhabdomyosarcomatous differentiation. To further clarify the clinical, radiographic, and pathologic features of this unusual variant, we report three additional cases of dedifferentiated chondrosarcoma with rhabdomyosarcomatous differentiation. The patients included two men and one woman; their mean age was 63 years. Tumors originated in the pelvis (ilium), scapula, and tibia. Two patients presented with radiographic findings typical of dedifferentiated chondrosarcoma, including a geographic, lytic lesion with areas of mineralization suggestive of cartilage in close association with a permeative component. The third patient presented with a primarily lytic, destructive lesion of the right iliac wing. Histologically, the tumors contained lobules of well-differentiated chondrosarcoma associated with a high-grade sarcoma with prominent rhabdomyoblasts. Immunohistochemical stains for actin and desmin were positive in all three tumors, and electron microscopy revealed evidence of skeletal muscle differentiation. All three patients died with metastatic disease, 1, 6, and 12 months postoperatively. This histologic variant of dedifferentiated chondrosarcoma is rare, but it shows radiographic and clinical features similar to "conventional" dedifferentiated chondrosarcoma, including a very poor prognosis.

Noninvasive grading of musculoskeletal tumors using PET.

Twenty-five patients with mass lesions involving the musculoskeletal system were studied with positron emission tomography (PET) in order to determine if a relationship exists between histologic grade and tumor uptake of [fluorine-18]2-deoxy-2-fluoro-D-glucose (FDG). There were 6 benign lesions and 19 malignant lesions of various grades. A high correlation (Rho = 0.83) was found between the normalized uptake of tracer and the NCl grade. The high-grade malignancies had significantly greater (p = 0.0091) uptake of FDG than the combination of benign lesions and low-grade malignancies. All lesions with a normalized uptake value of 1.6 or greater were high-grade, while all lesions less than 1.6 represented either benign tumors or low grade malignancies. This strong relationship between FDG uptake and grade among neoplasms from a wide variety of cell types within a single organ system suggests that the technique may be useful in predicting grade even when the cell type is unknown.

Diffuse and localized tenosynovial giant cell tumor and pigmented villonodular synovitis: a clinicopathologic and flow cytometric DNA analysis.

The DNA content and proliferative indexes of seven cases of tenosynovial giant cell tumor of tendon sheath, diffuse type (TGCT-D); 11 cases of tenosynovial giant cell tumor of tendon sheath, localized type (TGCT-L); and seven cases of pigmented villonodular synovitis (PVNS) were analyzed by flow cytometry in an attempt to assess objectively their biologic differences. Three cases of TGCT-D manifested an aneuploid DNA content and four had a diploid DNA pattern. All cases of TGCT-L and PVNS showed a diploid DNA content. The proliferative indexes for TGCT-D were significantly higher than those found in the other two groups. There was no histopathologic feature that correlated with the aneuploid DNA pattern found in two of the three cases of TGCT-D. Only one of the three aneuploid DNA content TGCT-D cases displayed marked cellular pleomorphism with dense fibrous stroma; in that case there was recurrence 4 years after initial excision. Our data further support that TGCT-D, TGCT-L, and PVNS are histopathologically similar but clinically distinct lesions. The high proliferative indexes of TGCT-D may reflect a rapid, uncontrolled growth that may explain its aggressive biologic behavior. The presence of an aneuploid DNA pattern in some cases of TGCT-D in this study, coupled with the reported chromosomal abnormalities and occurrence of malignant transformation in these lesions, clearly supports their neoplastic nature.

Bile acids. LXXIII. Synthesis of analogs of 7 alpha-hydroxy-4-cholesten-3-one as substrates for hepatic steroid 12 alpha-hydroxylase.

Analogs of 7 alpha-hydroxy-4-cholesten-3-one were prepared to ascertain structural features necessary for maximal activity of hepatic microsomal 12 alpha-steroid hydroxylase. Methyl 3 alpha,7 alpha-dihydroxy-5 beta-cholane-24-carboxylate derived from chenodeoxycholic acid was oxidized at C-3 with silver carbonate/Celite. The product was hydrolyzed and dehydrogenated with SeO2 to provide 3-oxo-7 alpha-hydroxy-4-cholene-24-carboxylic acid. 5 beta-Cholestane-3 alpha,7 alpha,25-triol and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol were similarly oxidized at C-3 and dehydrogenated to provide 7 alpha,25-dihydroxy-4-cholesten-3-one and 7 alpha,12 alpha,25-trihydroxy-4-cholesten-3-one, respectively. The products were characterized by thin-layer and gas chromatography, ultraviolet, infrared, proton resonance and mass spectrometry.

Caveat arthroscopos: extra-articular lesions of bone simulating intra-articular pathology of the knee.

In the period from 1977 to 1981, eleven patients with a primary bone neoplasm and one with a bone abscess, located in the shaft or distal end of the femur or the proximal part of the tibia, were referred to the Massachusetts General Hospital Orthopaedic Oncology Unit. All had had diagnostic or therapeutic arthroscopy. For one of the patients no roentgenograms had been made prior to arthroscopy. For another, roentgenograms had been made but were not repeated prior to the arthroscopy three months later. In six patients the lesions were clearly evident on the roentgenograms; they were not reported in four patients, while in two patients the lesions were not considered to be a contraindication to arthroscopy. Two lesions were located in the femoral shaft and one was in the popliteal space, but they had not been noted by the surgeon or radiologist. In four patients the lesion arising from the bone was biopsied through the arthroscope, introducing tumor cells into the joint and theoretically causing synovial seeding of the lesion. The problems raised by this study are obvious to all orthopaedic surgeons who perform arthroscopy. Any patient who is thought to have an intra-articular lesion must first be fully evaluated by history, physical examination, and, most importantly, appropriate biplane roentgenograms prior to the performance of any procedure. If a lesion arising from the bone is encountered during an arthroscopic procedure, the lesion must be biopsied not transsynovially, but through a separate extracapsular approach.

McKeever metallic hemiarthroplasty of the knee in unicompartmental degenerative arthritis. Long-term clinical follow-up and current indications.

Forty patients with forty-four unicompartmental McKeever metallic uncemented hemiarthroplasties were followed for five to thirteen years (average, eight years). Thirty-nine knees had a medial and five, a lateral arthroplasty. The age at surgery ranged from thirty-two to eight-two years (average, sixty-seven years). At the final follow-up, 70 per cent of the knees were rated as good or excellent. Seventy-nine per cent of the knees in patients who were less than sixty-five years old at the time of surgery were in these categories. Six knees (14 per cent) had required revision to either a unicompartmental or a bicompartmental total knee replacement. The average preoperative and postoperative knee flexion did not change, but knees with initially poor motion improved. The average preoperative flexion contracture of 10 degrees improved postoperatively to 5 degrees. Complications were rare and no cases of infection, peroneal palsy, or clinically detectable phlebitis occurred. Obesity did not seem to adversely affect the outcome. This study indicated that the McKeever unicompartmental metallic hemiarthroplasty can provide an attractive alternative in the treatment of unicompartmental degenerative arthritis when proximal tibial osteotomy is contraindicated or has failed or when the patient is too young, heavy, or active to consider total knee replacement.

Open tibial fractures with severe soft-tissue loss. Limb salvage compared with below-the-knee amputation.

The long-term outcomes and the quality of life were studied in patients who had had an open fracture of the tibial shaft with severe soft-tissue loss. Limb salvage with a free flap was attempted in twenty-seven patients (sixteen of whom had a successful procedure and were examined personally by us), while eighteen patients were managed concurrently with an early below-the-knee amputation. Soft-tissue coverage was successful in all but one patient in whom limb salvage had been attempted. Ultimately, however, five extremities were amputated, with an infection at the site of a non-union being the most common reason for amputation. The patients who had had limb salvage had more complications (p < 0.001), more operative procedures (p < 0.001), and a longer stay in the hospital (p < 0.05) than the patients who had had an early below-the-knee amputation. The long-term functional results for sixteen patients who had had a successful limb-salvage procedure (average duration of follow-up, thirty-five months) were compared with those for eighteen patients who had had a below-the-knee amputation (average duration of follow-up, forty-four months). The patients who had had a successful limb-salvage procedure took significantly more time to achieve full weight-bearing (p < 0.05), were less willing or able to work (p < 0.01), and had higher hospital charges (p < 0.006) than the patients who had been managed with an early below-the-knee amputation. They also had a significant decrease in motion at the ankle and subtalar joint in the injured leg compared with the contralateral leg (p < 0.001). A quality-of-life evaluation was possible for only thirteen of the patients who had had a successful limb-salvage procedure and for sixteen of the patients who had had a below-the-knee amputation. The two groups were similar in terms of their responses, but significantly more patients who had had limb salvage considered themselves severely disabled (p < 0.05). They also had more problems with the performance of occupational and recreational activities (p < 0.05). This study confirmed the reliability of modern microvascular free tissue techniques for the coverage of large soft-tissue defects associated with tibial fractures. It also showed that complications and difficulties in the restoration of osseous union are common and may be directly related to the less satisfactory functional, occupational, recreational, and quality-of-life outcomes that are seen in many patients who have had limb salvage.(ABSTRACT TRUNCATED AT 400 WORDS)