bluuebunny/crossref_metadata_2025 huggingface dataset:
Is aging programed?
Authors: Austad Steven N.
Published: September 2004

Development and morphogenesis may easily be thought of as programed, in the sense that they result from a sequence of cellular and molecular events designed by natural selection to produce a given adult phenotype. Aging, except in exceptional cases such as the rapid decay and death of Pacific salmon, is not design but decay. The decay of senescence is not due to natural selection's designing hand, but to its absence. The empirical difference between programed and nonprogramed senescence becomes evident when comparing the stereotypical steps leading to death in salmon contrasted with the lack of such stereotypy in most organisms such as humans and mice. Understanding the distinction between programed development and nonprogramed senescence helps focus attention on the phenotypic performance of adults, which is the focus of natural selection, and therefore be attentive to any unwanted pleiotropic side‐effects of genetic or environmental treatments which retard aging.
Altered cholesterologenic and lipogenic transcriptional profile in livers of aging Snell dwarf (Pit1dw/dwJ) mice
Authors: Boylston William H. , Gerstner Arpad , DeFord James H. , Madsen Mark , Flurkey Kevin , Harrison David E. , Papaconstantinou John
Published: September 2004

Several murine models demonstrate that mammalian longevity can be increased by single gene mutations affecting endocrine signalling, particularly via the GH/IGF‐1 axis. In this study, we identify age‐independent patterns of hepatic gene expression characteristic of long‐lived Snell (Pit1dw/dwJ) dwarf mice. Comparative microarray analysis of young and aged male livers was performed to discover specific genes differentially expressed between Pit1dw/dwJ and control mice. Further examination by real‐time RT‐PCR confirmed that transcripts encoding HMG‐CoA synthase‐1, HMG‐CoA reductase, farnesyl diphosphate synthase, isopentenyl pyrophosphate isomerase, mevalonate decarboxylase, squalene epoxidase, lanosterol demethylase, malic enzyme and apolipoprotein A‐IV were significantly decreased in both male and female Pit1dw/dwJ livers at 3–5 and 24–28 months of age. In contrast, transcripts encoding the β3‐adrenergic receptor, lipoprotein lipase, PPARγ and a very low‐density lipoprotein receptor homologue were increased significantly in dwarf livers relative to age‐matched controls. These studies reveal enduring transcriptional changes characteristic of Pit1dw/dwJ dwarf mice that involve genes regulating cholesterol biosynthesis, fatty acid metabolism and lipoprotein homeostasis. Linked to global energy metabolism, this stable shift in hepatic gene expression may contribute to longevity determination by influencing particular metabolic functions often compartmentalized within the mitochondrion and peroxisome; further this metabolic shift may also parallel many transcriptional changes induced by caloric restriction.
coq7/clk‐1 regulates mitochondrial respiration and the generation of reactive oxygen species via coenzyme Q
Authors: Nakai Daisuke , Shimizu Takahiko , Nojiri Hidetoshi , Uchiyama Satoshi , Koike Hideo , Takahashi Mayumi , Hirokawa Katsuiku , Shirasawa Takuji
Published: September 2004

coq7/clk‐1 was isolated from a long‐lived mutant of Caenorhabditis elegans, and shows sluggish behaviours and an extended lifespan. In C. elegans and Saccharomyces cerevisiae, coq7/clk‐1 is required for the biosynthesis of coenzyme Q (CoQ), an essential co‐factor in mitochondrial respiration. The clk‐1 mutant contains dietary CoQ8 from Escherichia coli and demethoxyubiquinone 9 (DMQ9) instead of CoQ9. In a previous study, we generated COQ7‐deficient mice by targeted disruption of the coq7 gene and reported that mouse coq7/clk‐1 is also essential for CoQ synthesis, maintenance of mitochondrial integrity and neurogenesis. In the present study, we rescued COQ7‐deficient mice from embryonic lethality and established a mouse model with decreased CoQ level by transgene expression of COQ7/CLK‐1. A biochemical analysis showed a concomitant decrease in CoQ9, mitochondrial respiratory enzyme activity and the generation of reactive oxygen species (ROS) in the mitochondria of CoQ‐insufficient mice. This implied that the depressed activity of respiratory enzymes and the depressed production of ROS may play a physiological role in the control of lifespan in mammalian species and of C. elegans.
Molecular analyses of mtDNA deletion mutations in microdissected skeletal muscle fibers from aged rhesus monkeys
Authors: Gokey Nolan G. , Cao Zhengjin , Pak Jeong W. , Lee Damian , McKiernan Susan H. , McKenzie Debbie , Weindruch Richard , Aiken Judd M.
Published: September 2004

Mitochondrial DNA (mtDNA) deletion mutations co‐localize with electron transport system (ETS) abnormalities in rhesus monkey skeletal muscle fibers. Using laser capture microdissection in conjunction with PCR and DNA sequence analysis, mitochondrial genomes from single sections of ETS abnormal fibers were characterized. All ETS abnormal fibers contained mtDNA deletion mutations. Deletions were large, removing 20–78% of the genome, with some to nearly all of the functional genes lost. In one‐third of the deleted genomes, the light strand origin was deleted, whereas the heavy strand origin of replication was conserved in all fibers. A majority (27/39) of the deletion mutations had direct repeat sequences at their breakpoints and most (36/39) had one breakpoint within or in close proximity to the cytochrome b gene. Several pieces of evidence support the clonality of the mtDNA deletion mutation within an ETS abnormal region of a fiber: (a) only single, smaller than wild‐type, PCR products were obtained from each ETS abnormal region; (b) the amplification of mtDNA from two regions of the same ETS abnormal fiber identified identical deletion mutations, and (c) a polymorphism was observed at nucleotide position 16103 (A and G) in the wild‐type mtDNA of one animal (sequence analysis of an ETS abnormal region revealed that mtDNA deletion mutations contained only A or G at this position). Species‐specific differences in the regions of the genomes lost as well as the presence of direct repeat sequences at the breakpoints suggest mechanistic differences in deletion mutation formation between rodents and primates.
The M3 muscarinic receptor i3 domain confers oxidative stress protection on calcium regulation in transfected COS‐7 cells
Authors: Joseph James A. , Fisher Derek R. , Carey Amanda , Szprengiel Aleksandra
Published: September 2004

Evidence suggests that muscarinic receptors (MAChRs) are involved in various aspects of neuronal and vascular functioning, and that there is selective oxidative stress sensitivity (OSS) among MAChR subtypes. COS‐7 cells transfected with M1, M2 and M4 subtypes show greater OSS than the M1 and M3 subtypes, as seen by the decreased ability of cells to extrude or sequester calcium (Ca2+) following exposure to dopamine (DA) or Aβ 25–35, and depolarization by oxotremorine. We sought to determine which receptor domain may be responsible for the differential vulnerability to OS between ‘OS‐sensitive’ (M1) and ‘non‐sensitive’ (M3) subtypes. Comparison of the amino acid sequences of each receptor has shown that the third cytoplasmic loop (i3 loop) is the domain with the most variability between the two subtypes. Therefore, mutations were made by either deleting or exchanging the i3 loop of M1 and M3 receptors. Experiments revealed that deletions of the i3 loop increased DA sensitivity (a lower percentage of cells showing recovery of [Ca2+]i following depolarization) in both receptors. Chimerics of M1 in which the i3 loop of the M3 was exchanged with the i3 loop of the M1 (M1M3i3) showed that DA sensitivity was reduced (a greater percentage of cells showing increases in calcium clearance) following depolarization. The M3 chimerics containing the M1 i3 loop (M3M1i3) offered no protection against DA‐induced decrements in calcium buffering. Results suggest that the longer i3 loop of the M3 may decrease OSS, possibly playing a role in targeting antioxidants to specific receptor sites that impart OSS.
Diagnostic evaluation of planar and tomographic ventilation/perfusion lung images in patients with suspected pulmonary emboli
Authors: Bajc Marika , Olsson Carl‐Gustav , Olsson Berit , Palmer John , Jonson Björn
Published: September 2004

Planar lung ventilation/perfusion scintigraphy (V/PPLANAR) is a standard method for diagnosis of pulmonary embolism (PE). The goals of this study were to test whether the diagnostic information of ventilation/perfusion tomography (V/PSPET) applied in clinical routine might enhance information compared with V/PPLANAR and to streamline data processing for the demands of clinical routine. This prospective study includes 53 patients suspected for PE referred for lung scintigraphy. After inhalation of 99mTc‐DTPA planar ventilation imaging was followed by tomography, using a dual‐head gamma camera. 99mTc‐MAA was injected i.v. for perfusion tomography followed by planar imaging. Patients were examined in supine position, unchanged during V/P tomography. Two reviewers evaluated V/PPLANAR and V/PSPET images separately and randomly. Mismatch points were calculated on the basis of extension of perfusion defects with preserved ventilation. Patients were followed up clinically for at least 6 months. With V/PSPET the number of patients with PE was higher and 53% more mismatch points were found. In V/PSPET interobserver variation was less compared with V/PPLANAR. Ancillary findings were observed by both techniques in half of the patients but more precisely interpreted with V/PSPET. V/PSPET shows more and better delineated mismatch defects, improved quantification and less interobserver variation compared with V/PPLANAR. V/PSPET is amenable to implementation for clinical routine and suitable even when there is demand for a high patient throughput.
Quadriceps strength assessed by magnetic stimulation of the femoral nerve in normal subjects
Authors: Hamnegård Carl‐Hugo , Sedler Margareta , Polkey Michael I. , Bake Björn
Published: September 2004

Magnetic stimulation of the femoral nerve is a new technique for assessment of quadriceps strength by measurement of twitch tension (TwQ), a test that is independent of subject motivation. In this study, we sought to establish better define normal values by measurement of TwQ in 45 normal subjects. Supramaximal stimulation, as judged by TwQ, was achieved in 43 of 45 subjects at a mean of 90% of maximum stimulator output. The mean TwQ was 7·3 kilograms force (kgf) (SD 2·3) for women and 9·8 kgf (SD 2·5) for men. The mean maximal voluntary contraction (MVC) force was 48·0 kgf (SD 9·2) for women and 70·1 kgf (15·2) for men. The mean TwQ/MVC ratio was 0·15 for both women and men. Significant correlations were observed between TwQ and weight (r = 0·33, P<0·03) and height (r = 0·32, P<0·03) but these were weak and only partially explained observed variance. Our data confirm that magnetic femoral nerve stimulation is generally acceptable to naive subjects. Values are provided as a function of weight in normal subjects.
Pulsed tissue Doppler imaging for the detection of myocardial ischaemia, a comparison with myocardial perfusion SPECT
Authors: Blomstrand Peter , Maret Eva , Ohlsson Jan , Scheike Morten , Karlsson Jan‐Erik , Säfström Kåge , Swahn Eva , Engvall Jan
Published: September 2004

In order to compare the diagnostic ability of pulsed tissue Doppler and myocardial perfusion Single Photon Emission Computed Tomography (SPECT) in patients with a history of unstable coronary artery disease, CAD, 26 patients, 22 men and four women, age 47–76 years, were investigated in a prospective study, 5–10 day after an episode of unstable angina. Tissue Doppler and two‐dimensional echocardiography were performed during dobutamine stress testing and myocardial scintigraphy after bicycle exercise and at rest.

Patients with a normal SPECT had higher peak systolic velocity during dobutamine infusion, 18.9 ± 4.1 cm s−1, than patients with ischaemia, 12.2 ± 3.8 cm s−1 (P<0.001) or scar, 8.8 ± 3.0 cm s−1 (P<0.01). In a territorial analysis the difference in peak systolic velocity between areas with a normal and abnormal SPECT was less apparent. Failure to achieve ≥13 cm s−1 in mean‐peak systolic velocity was the most accurate criterion for detection of significant CAD on SPECT. We conclude that pulsed tissue Doppler can be used for objective quantification of left ventricular wall motion during dobutamine stress testing and for identification of patients with CAD on SPECT but not for identification of regional ischaemia.
Plethysmography without venous occlusion for measuring forearm blood flow: comparison with venous occlusive method
Authors: Chuah Seong S. , Woolfson Peter I. , Pullan Brian R. , Lewis Philip S.
Published: September 2004

Limb blood flow is widely used as an indicator of the human vascular properties. There are only few non‐invasive methods for its measurement such as venous occlusion plethysmography. However, several authors have questioned its validity. The problems appear to be related to the process of venous occlusion. We developed two methods to measure forearm blood flow by plethysmography without venous occlusion in combination with Doppler velocimetry (without imaging). Method 1: the gradient of a tangent drawn on the latter part of the down stroke of the plethysmographic volume pulse is an approximation of venous blood flow in the absence of diastolic blood flow. At equilibrium, it equals the average arterial flow in a cardiac cycle. The Doppler velocity waveform recorded simultaneously allows improvement of this approximation when there is diastolic blood flow. Method 2: the volume pulse detected by a plethysmograph calibrated in absolute volume is used to calibrate the velocity waveform recorded simultaneously to produce an approximation of arterial volumetric flow waveform. Bland‐Altman analysis shows both methods have good correlation and agreement with venous occlusion plethysmography at rest. Method 1: mean difference (blood flow measured by venous occlusion minus calculated flow) = 0·10 ml/pulse (±0·18), limits of agreement = −0·41 and 0·61 ml/pulse. Method 2: mean difference = −0·041 ml/pulse (±0·15), limits of agreement = −0·45 and 0·37 ml/pulse. During hyperaemia, venous occlusion plethysmography grossly underestimated relative to the new methods. The new methods are not dependent on venous occlusion and produce consistent results with or without hyperaemia.
Beat‐to‐beat oscillations in pulse pressure
Authors: Virtanen Raine , Jula Antti , Kuusela Tom , Airaksinen Juhani
Published: September 2004

We compared 5‐min standard deviations (SD) and frequency domain measures of beat‐to‐beat pulse pressure (PP) variability with those of RR‐interval, systolic (SBP) and diastolic (DBP) blood pressure variabilities, and with cross‐spectral baroreflex sensitivity (BRS) in a population‐based sample of 150 healthy individuals, aged 35–64 years. Beat‐to‐beat variability of PP was composed of similar frequency components as the other spectral variabilities, and was closely related to SBP variability. The proportion of high frequency (HF) component from overall variability was higher in PP variability than in SBP and DBP variabilities. The low frequency (LF) component and the SD of beat‐to‐beat PP correlated inversely with BRS (−0·48 and −0·32, respectively; P<0·001 for both). To test a hypothesis that arterial stiffening is associated with increased beat‐to‐beat oscillation in PP, we examined associations of beat‐to‐beat PP variability with risk factors of atherosclerosis, i.e. with age, gender, smoking, blood pressure, body mass index, serum lipids, glucose, insulin and homeostasis model assessment of insulin resistance. The SD of beat‐to‐beat PP variability correlated with age (0·21, P = 0·010), PP (0·31, P<0·001) and body mass index (0·22, P = 0·008). The LF component of PP variability correlated not only with age (0·17, P = 0·041), PP (0·27, P = 0·001) and body mass index (0·22, P = 0·007), but also with serum insulin (0·17, P = 0·042), homeostasis model assessment of insulin resistance (0·18, P = 0·031) and serum triglycerides (0·16, P = 0·048). Our findings suggest that increased beat‐to‐beat oscillation of PP reflects arterial stiffening and impaired baroreflex function.
Photosensitivity in lupus erythematosus
Authors: Scheinfeld Noah , Deleo Vincent A
Published: September 2004

Background: Lupus erythematosus is a systemic disease process that may manifest with a variety of internal and cutaneous findings. Photosensitivity is one the most common manifestations of lupus erythematosus. In patients with lupus erythematosus, there is a relationship between exposure to ultraviolet light, autoantibodies, genetics and other factors in the development of photosensitivity.

Methods: Literature was reviewed on the topics of lupus erythematosus and photosensitivity discussed together and separately. The suggested mechanisms for their relationship were reviewed and analyzed.

Results: Photosensitivity's relationship to and influence on the systemic manifestations of lupus remain to be defined. Mechanisms for photosensitivity might include: modulation of autoantibody location, cytotoxic effects, apoptosis induction with autoantigens in apoptotic blebs, upregulation of adhesion molecules and cytokines, induction of nitric oxide sythase expression and ultraviolet‐generated antigenic DNA. Tumor necrosis factor α also seems to play a role in the development of photosensitivity.

Conclusion: The basis for photosensitivity in lupus has yet to be fully defined. It is more commonly associated with subacute and tumid lupus erythematosus than with other variants. Anti‐Ro antibodies appear to relate to photosensitivity. Tumor necrosis factor α polymorphisms appear to be important in some variants of lupus with photosensitivity. There is no sin que non antibody or mutation of photosensitivity in lupus. In patients with lupus, more work needs to be done to define the mechanisms of photosensitivity.
Modest in vivo exposure to solar wavelengths induces a visible absorbing chromophore in Skh‐1 mouse epidermis
Authors: Menter Julian M. , Sayre Robert M. , Dowdy John C. , Etemadi Amir A. , Patta Abrienne M. , Chappell Johnathan , Willis Isaac
Published: September 2004

Background/purpose: In the previous work, we correlated epidermal hyperplasia with increased epidermal absorption in the 250–400 nm region. During a recent review of that work, the apparent formation of a chromophore, with absorption slightly longer than 400 nm, in the epidermis of irradiated animals was noted. In this study, we have extended the transmission measurement to include the 250–800 nm region.

Methods: Age‐matched Skh‐1 hairless mice were separated into three groups. One group was irradiated with 6.3 J/cm2 (0.9 minimal erythemal dose; MED) of solar simulating ultraviolet radiation (SSUVR) five times/week for 2 weeks, then increased to 1.1 MED (7.1 J/cm2) for two additional weeks (20‐day group). A second 10‐day group, added halfway through the protocol, was irradiated with 0.9 MED five times/week for 2 weeks. The control group received no UV irradiation. Routine H&E staining and epidermal absorption spectral analysis were carried out on biopsy specimens from each animal.

Results: This work confirms the development or enhancement of a visible chromophore with a maximum absorption at ca 412 nm. This peak appears to be radiation dose dependent. It can be discerned in both the groups, albeit more prominently in the 20‐day animals. The absorption is sufficiently strong to impart a yellow to reddish appearance to skin viewed in full spectrum visible light.

Conclusions: Accumulation of such a chromophore in humans may contribute to the coloration of chronically exposed skin. The absorption strength and wavelength location of the peak is strongly suggestive of a heme‐like compound. We are currently conducting experiments to further characterize this chromophore.
Blue light phototherapy in the treatment of acne
Authors: Tzung Tien‐Yi , Wu Kuan‐Hsing , Huang Mei‐Lun
Published: September 2004

Background: Blue light irradiation is known to be effective against acne. However, the profile of a good candidate is still unclear.

Methods: Thirty‐one Taiwanese with symmetrical facial acne were irradiated with blue light on one side of the face selected randomly twice weekly for 4 consecutive weeks. The other half of the face was left untreated as control. Parameters, including scar type, pore size, and facial follicular porphyrin fluorescence intensity, were documented. The severity of acne was assessed before the treatment, after two, four, and eight sessions of treatment, and 1 month after the treatment was completed.

Results: Compared with the non‐irradiation side, eight sessions of blue light irradiation were effective in acne treatment (P<0.001). Gender (P=0.471), scar type (P‐values of pitted, atrophic, and hypertrophic type were 0.688, 0.572, and 0.802, respectively), pore size (P=0.755), and pretreatment fluorescence intensity (P=0.656) could not be used as predictive factors of therapeutic effectiveness. Compared with pretreatment, nodulocystic lesions tended to worsen despite treatment. In addition, the therapeutic effectiveness was not related to the fluorescence intensity change (P=0.812).

Conclusions: Blue light irradiation is effective in acne treatment. Patients without nodulocystic lesions are better candidates for blue light irradiation.
Prevention of ultraviolet‐induced skin pigmentation
Authors: Moyal Dominique
Published: September 2004

Background/purpose: Exposure to ultraviolet (UV) radiation increases skin pigmentation and usually results in an even darkening of the skin. However, it may also occasionally lead to the development of hyperpigmented lesions due to a local overproduction of pigment. Skin pigmentation is induced both by UVB and UVA rays.

Methods: The in vivo protection by sunscreens against pigmentation was studied using the determination of a level of protection against pigmentation based on the standardized sun protection factor (SPF) test method. The method includes delayed UVB and UVA pigmentations. The level of prevention against pigmentation was determined 7 days after exposure to solar‐simulated radiation by visual assessment. It was calculated using the ratio of the minimal pigmenting dose on protected skin to the minimal pigmenting dose on unprotected skin. Broadspectrum UVB/UVA filters, Mexoryl®SX and Mexoryl®XL, and complete formula were tested.

Results: Protection against pigmentation correlates with the concentration of Mexoryl®SX. The levels of protection obtained show a synergetic effect of Mexoryl®SX when associated with Mexoryl®XL. When different products having the same SPF (same protection against erythema) and different levels of UVA protection are compared, only sunscreen products with a high level of UVA protection show a similar level of protection against sunburn and pigmentation. Products with low UVA protection have a lower capacity of preventing induced pigmentation compared with their efficacy against erythema.

Conclusions: These studies have evidenced that SPF determination was not sufficient to account for the efficiency in preventing pigmentation and that UVA protection was an essential part of this prevention.
Positive photobiological investigation in reticular erythematous mucinosis syndrome
Authors: Adamski H. , Le Gall F. , Chevrant‐Breton J.
Published: September 2004

Background: Reticular erythematous mucinosis (REM) syndrome is a rare disorder. Its clinical course is cyclic with remissions and exacerbations. In this disease, photosensitivity has previously been noticed but rarely demonstrated. We report three new cases with positive photobiological investigation.

Case reports: Three patients (two males, one female) with a mean age 47 years were seen with reticular erythematous papules on the upper chest and or back. After sun exposure, the lesions were exacerbated. Skin biopsies showed dermal lymphocytic perivascular infiltration with mucin deposition between collagen bundles. Direct immunofluorescence was negative. Antinuclear antibodies were absent. In cabin, ultraviolet (UV)A exposure reproduced clinically and histologically REM lesions in our cases. UVA and UVB provocating phototests were negative. In all patients treatment with oral antimalarials and external photoprotection was effective.

Conclusions: In our patients, we confirm the photosensitive feature of REM syndrome by provocative irradiation in UVA cabin. The mechanism of triggering is actually unclear. It is supposed that UV radiation, heat, and perspiration are necessary to reveal this affection.
Topical calcipotriene and narrowband ultraviolet B in the treatment of vitiligo
Authors: Kullavanijaya Prisana , Lim Henry W.
Published: September 2004

Background: Treatment of vitiligo, despite significant advances made in the past few years, remains to be a challenge. Narrowband ultraviolet (NB‐UVB) has emerged as an important therapeutic option for this condition.

Objective: To evaluate whether the combination of calcipotriene ointment and NB‐UVB could enhance the efficacy of NB‐UVB alone.

Methods: An open, bilateral comparison study was performed in 20 patients with symmetrical vitiligo between August 2001 and October 2002. All patients received NB‐UVB three times per week. Calcipotriene ointment was applied to lesions on the left side of the body. Response was graded visually as significant (66–100% repigmentation), moderate (26–65%), mild (10–25%), and minimal (<10%).

Results: Seventeen patients (six females, 11 males) completed the study. Eight patients (8/17=47%) had significant repigmentation after 67–180 treatments, six patients (35%), one patient (6%), and two patients (12%) had moderate, mild, and minimal repigmentation after 40–160, 57, and 14–21 treatments, respectively. Nine of the 17 patients had an appreciably better improvement on the NB‐UVB and calcipotriene side by 29–114 treatments. In six of these patients, differences were still observed at the end of the study period. No side effects were noted.

Conclusion: Combination therapy of topical calcipotriene and NB‐UVB is a therapeutic option that could be considered in the management of patients with vitiligo.
Durability of the sun protection factor provided by dihydroxyacetone
Authors: Faurschou A. , Wulf H.C.
Published: September 2004

Background/Purpose: The sunless tanning agent dihydroxyacetone (DHA) is known to protect against longwave ultraviolet radiation (UVA) and visible light. Recently, our laboratory has shown that DHA in addition offers a modest sun protection factor (SPF) in humans. We conducted this study in order to investigate the durability of the SPF provided by DHA.

Methods: Ten healthy volunteers were treated with 20% DHA cream twice in three areas on the volar forearm. One, 5 and 7 days after the second application the participants were phototested with simulated sunlight in each area. Blue reflectance was used to measure the skin coloration by DHA in the test sites.

Results: DHA generated a significant SPF of 3.0 at day 1, 2.0 at day 5 and 1.7 at day 7 (P<0.0001). The SPF was positively correlated to the change in blue reflectance (r=0.39, P=0.034). The loss of SPF unit/day was not significantly different between the subjects (P<0.122). However, the intercepts were significantly different (P<0.0001) indicating differences in the initial SPF obtained among the subjects.

Conclusions: The SPF of DHA decreases with the same loss of SPF unit/day between humans and the durability of the SPF thus depends on the initial SPF provided.
Oxidative Damage of Biomolecules in Mouse Liver Induced by Morphine and Protected by Antioxidants
Authors: Zhang Yun‐Tao , Zheng Qiu‐Sheng , Pan Jing , Zheng Rong‐Liang
Published: September 2004

Abstract: This study investigates the oxidative damage of biomolecules in livers of mice treated with morphine intraperitoneally. The oxidative damage of DNA as measured by single cell electrophoresis and high‐performance liquid chromatography equipped with electrochemical and UV detection, the protein carbonyl content was measured by 2,4‐dinitrophenylhydrazine method, and the malondialdehyde content was measured by the HPLC method. The activities of antioxidative enzymes, superoxide dismutase, catalase and glutathione peroxidase, and the activity of alanine aminotransferase were assayed by spectrophotometer method. Glutathione and oxidized glutathione were detected by fluorescence spectrophotometer method. All the indexes of oxidative damage, such as 8‐OHdG, protein carbonyl group and malondialdehyde content, and the activity of alanine aminotransferase (n=27) increased significantly compared to those of control (n=27) (P<0.01) in livers of morphine‐administered alone mice, while the indexes related with the in vivo antioxidative capacity, such as the ratio of glutathione and oxidized glutathione, activities of superoxide dismutase, catalase and glutathione peroxidase significantly decreased (P<0.01). When mice were treated with morphine combined with exogenous antioxidants, glutathione and ascorbic acid, all the indexes of oxidative damage and the activity of alanine aminotransferase showed no changes as compared to those of control (P>0.05), i.e., both glutathione and ascorbic acid completely abolished the damage of morphine on the hepatocyte. These results implied that morphine caused a seriously oxidative stress in mice livers and hence caused hepatotoxicity, while exogenous antioxidants were able to prevent the oxidative damage of biomolecules and hepatotoxicity caused by morphine. Thus, blocking oxidative damage may be a useful strategy for the development of a new therapy for opiate abuse.
Effect of Carvedilol on Ca2+ Movement and Cytotoxicity in Human MG63 Osteosarcoma Cells
Authors: Liu Chun Peng , Jan Chung‐Ren
Published: September 2004

Abstract: Carvedilol is a useful cardiovascular drug for treating heart failure, however, the in vitro effect on many cell types is unclear. In human MG63 osteosarcoma cells, the effect of carvedilol on intracellular Ca2+ concentrations ([Ca2+]i) and cytotoxicity was explored by using fura‐2 and tetrazolium, respectively. Carvedilol at concentrations greater than 1 μM caused a rapid rise in [Ca2+]i in a concentration‐dependent manner (EC50=15 μM). Carvedilol‐induced [Ca2+]i rise was reduced by 60% by removal of extracellular Ca2+. Carvedilol‐induced Mn2+‐associated quench of intracellular fura‐2 fluorescence also suggests that carvedilol induced extracellular Ca2+ influx. In Ca2+‐free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+‐ATPase, caused a monophasic [Ca2+]i rise, after which the increasing effect of carvedilol on [Ca2+]i was inhibited by 50%. Conversely, pretreatment with carvedilol to deplete intracellular Ca2+ stores totally prevented thapsigargin from releasing more Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5‐trisphosphate‐dependent Ca2+ mobilizer)‐induced, but not carvedilol‐induced, [Ca2+]i rise. Pretreatment with phorbol 12‐myristate 13‐acetate and forskolin to activate protein kinase C and adenylate cyclase, respectively, did not alter carvedilol‐induced [Ca2+]i rise. Separately, overnight treatment with 0.1–30 μM carvedilol inhibited cell proliferation in a concentration‐dependent manner. These findings suggest that in human MG63 osteosarcoma cells, carvedilol increases [Ca2+]i by stimulating extracellular Ca2+ influx and also by causing intracellular Ca2+ release from the endoplasmic reticulum and other stores via a phospholipase C‐independent manner. Carvedilol may be cytotoxic to osteoblasts.
Early Onset of Cisplatin‐Induced Nephrotoxicity in Streptozotocin‐Diabetic Rats Treated with Insulin*
Authors: Sarangarajan Rangaprasad , Cacini William
Published: September 2004

Abstract: Mechanism of protection against cisplatin nephrotoxicity in streptozotocin‐diabetic rats is unclear but is associated with decreased renal platinum accumulation. This study was designed to determine whether normalization of hyperglycaemia by insulin treatment to six week streptozotocin‐diabetic rats reversed protection against cisplatin nephrotoxicity. Male Sprague‐Dawley rats divided into 3 groups (n=10/group) (1) non‐diabetic (2) untreated streptozotocin‐diabetic and (3) insulin‐treated streptozotocin‐diabetic groups were rendered diabetic using streptozotocin (65 mg/kg body weight, intravenous). At the end of 6 weeks, Group 3 animals were treated with insulin (subcutaneously) for 21 days to normalize glucose. After 21 days of insulin treatment, the mean±S.D. plasma glucose (mg%) in Group 3 animals at 144.8±22.03, was significantly lower than Group 2 animals (412±24.69) and comparable to age‐matched non‐diabetic (Group 1) animals. Blood urea nitrogen at 24 hr after intraperitoneal administration of cisplatin (5 mg/kg body weight) increased by a factor 2.5 in Group 3 compared to 1.1 and 1.3 in Group 1 and Group 2 animals respectively. In the same animals, at 96 hr the blood area nitrogen increased by a factor of 3.2 and 2.9 in Group 1 and Group 3 respectively compared to 1.14 for Group 2 animals. Renal platinum levels in Group 1, Group 2 and Group 3 after 96 hr after cisplatin administration were 6.92±0.83, 3.46±0.77 & 6.20±0.64 (μg/g wet weight of tissue) respectively. Results indicate that 21 day insulin treatment to streptozotocin‐diabetic animal reverses protection against cisplatin toxicity. Moreover, insulin treatment increased the susceptibility of streptozotocin‐diabetic rats to cisplatin‐induced renal toxicity.
Dose‐Dependent Neovascularization‐Promoting Effect of Adenovirus Vector CI‐1023 in a Rat Hindlimb Ischaemic Model
Authors: Wang He , Keiser Joan A. , Olszewski Bronia , Brammer David , Gordon David
Published: September 2004

Abstract: CI‐1023 (AdGVVEGF121.10) is a replication‐deficient adenovirus vector (complete E1a−, partial E1b−, partial E3−) delivering human vascular endothelial growth factor‐121 gene. Previous studies from this group have established that CI‐1023 can successfully transfer human vascular endothelial growth factor‐121 gene resulting in local tissue expression of vascular endothelial growth factor protein. The purpose of this study was to evaluate neovascularization‐promoting potency and efficacy of CI‐1023 in a wide dose range. In a rat hindlimb ischaemic model, we measured neovascularization‐promoting effect of CI‐1023 using three end‐points: post mortem angiography, immuno‐histochemisty and Laser Doppler scanning of tissue blood perfusion. Neovascularization‐promoting activity of CI‐1023 over the dose range of 4×106 pu−4×1010 pu was evaluated. Our data demonstrated an obvious dose‐dependent effect between 4×106 pu−4×108 pu. The neovascularizing effect is somewhat plateaued at the levels between 4×108 pu and 4×1010 pu. We conclude CI‐1023 is a potent neovascularization‐promoting compound, with a dose‐dependent effect between 4×106 pu−4×108 pu in the rat hindlimb ischaemic model.
Specification of the Structure of Oximes Able to Reactivate Tabun‐Inhibited Acetylcholinesterase
Authors: Cabal Jiří , Kuča K. , Kassa J.
Published: September 2004

Abstract: The efficacy of various oximes to reactivate acetylcholinesterase phosphorylated by tabun (O‐ethyl‐N,N‐dimethyl phosphoramidocyanidate) was tested by in vitro and in vivo methods. The oximes commonly used for the treatment of acute poisonings with highly toxic organophosphates appeared to be almost ineffective (HI‐6, pralidoxime, methoxime) or just slightly effective (obidoxime) against tabun. On the other hand, trimedoxime seemed to be a significantly more efficacious reactivator than the others in the case of tabun poisonings. In vitro, the concentration of trimedoxime corresponding to 1.0 mmol/l was able to reach 50% reactivation of tabun‐inhibited brain acetylcholinesterase. Higher reactivating potency of trimedoxime in comparison with the other commonly used oximes was demonstrated by in vivo method, too. In addition, other structural analogues of trimedoxime were found to be efficacious in counteracting tabun‐induced acetylcholinesterase inhibition although not as efficacious as trimedoxime itself. Some effective acetylcholinesterase reactivators were characterised by dissociation constant of enzyme‐reactivator complex as well as enzyme‐inhibitor‐reactivator complex and by rate constant of reactivation.
Microglial Calcium Responses to Platelet‐Activating Factor are Inhibited by Analogue CAS 99103‐16‐9 and Dihydropyridine PCA 4248 but Not by Ginkgolide A
Authors: Ranasinghe Saman , Bolsover Stephen
Published: September 2004

Abstract: Calcium signals evoked in N9 microglial cells were monitored using the calcium indicator dye Fluo‐4 in a fluorescence imaging plate reader. Platelet activating factor in the range 100 nM to 20 μM elicited graded calcium responses. The analogue CAS 99103‐16‐9 inhibited the evoked calcium rise with an apparent KB of 1.3±0.4 μM. The dihydropyridine PCA 4248 inhibited the evoked calcium rise with an apparent KB of 1.2±0.2 μM. Ginkgolide A at concentrations up to 18 μM had no effect on the evoked calcium rise. While CAS 99103‐16‐9 and PCA 4248 appear to be simple competitive inhibitors of platelet‐activating factor responses, the efficacy of ginkgolide in more complex pharmacological situations may result from an action at a site other than the platelet‐activating factor receptor.
rDNA-RFLP identification ofCandidaspecies in immunocompromised and seriously diseased patients
Authors: Pinto Patrícia M , Resende Maria A , Koga-Ito Cristiane Y , Ferreira José A.G , Tendler Miriam
Published: September 2004

PCR was used to amplify a targeted region of the ribosomal DNA of 76 Candida spp. isolates from immunocompromised and seriously diseased patients. Thirty-seven strains isolated from different anatomical sites of 11 patients infected with HIV (Vitória, ES, Brazil), 26 isolates from patients under treatment at Odilon Behrens Hospital and 13 isolates from skin and urine samples from São Marcos Clinical Analysis Laboratory (Belo Horizonte, Brazil) were scored. Fragments of rDNA were amplified using primer pairs ITS1-ITS4, for the amplification of ITS1 and ITS2 regions, including the gene for the 5.8s subunit. Amplification resulted in fragments ranging in size from 350 to 950 bp. Amplicons were digested with eight restriction enzymes. A pattern of species-specificity among the different medically important Candida species could be identified following restriction digestion of the PCR products. Candida albicans was the species most frequently observed, except for the group of newborns under treatment at the Odilon Behrens Hospital and for the isolates from the clinical analysis laboratory. C. parapsilosis was the species most frequently observed in these two groups.Key words: polymerase chain reaction, restriction fragment length polymorphism, candidosis, Candida spp.
Production of ribonucleotides by autolysis of Pichia anomala mutant and some physiological activities
Authors: Lee Jong-Soo , Hyun Kwang-Wook , Jeong Seung-Chan , Kim Jae-Ho , Choi Young J , Miguez Carlos B
Published: September 2004

Various mutants of Pichia anomala were isolated by ethyl methanesulfonate (EMS) treatment and UV irradiation through cycloheximide resistance and KCl sensitivity. The selected mutant HA-2 accumulated a higher content of RNA and grew faster than the wild-type strain in yeast extract–malt (YM) broth. Autolysis of the HA-2 mutant at 60 °C and pH 7.0 for 6 h was the best condition to obtain maximum yields of 5′-ribonucleotides, inosinic monophosphate (IMP) (6.2 mg/g biomass) and guanylic monophosphate (GMP) (35.5 mg/g biomass). The yield of adenylic monophosphate (AMP) (7.8 mg/g biomass) was optimal at 60 °C at pH 6.5 for 6 h. The inhibitory activity of the angiotensin-converting enzyme and the nitrite-scavenging activity for autolysates of the HA-2 mutant were about 13.0% and 47.0% higher than those of native strain, respectively.Key words: Pichia anomala mutant, 5′-ribonucleotides, adenylic monophosphate (AMP), guanylic monophosphate (GMP), inosinic monophosphate (IMP), autolysate.
Indigenous bacteria with antagonistic and plant-growth-promoting activities improve slow-filtration efficiency in soilless cultivation
Authors: Déniel F , Rey P , Chérif M , Guillou A , Tirilly Y
Published: September 2004

In tomato soilless culture, slow filtration allows one to control the development of diseases caused by pathogenic microorganisms. During the disinfecting process, microbial elimination is ensured by mechanical and biological factors. In this study, system efficacy was enhanced further to a biological activation of filter by inoculating the pozzolana grains contained in the filtering unit with 5 selected bacteria. Three strains identified as Pseudomonas putida and 2 as Bacillus cereus came from a filter whose high efficiency to eliminate pathogens has been proven over years. These 5 bacteria displayed either a plant growth promoting activity (P. putida strains) or antagonistic properties (B. cereus strains). Over the first months following their introduction in the filter, the bacterial colonisation of pozzolana grains was particularly high as compared to the one observed in the control filter. Conversely to Bacillus spp. populations, Pseudomonas spp. ones remained abundant throughout the whole cultural season. The biological activation of filter unit very significantly enhanced fungal elimination with respect to the one displayed by the control filter. Indeed, the 6-month period needed by the control filter to reach its best efficacy against Fusarium oxysporum was shortened for the bacteria-amended filter; in addition, a high efficacy filtration was got as soon as the first month. Fast colonization of pozzolana grains by selected bacteria and their subsequent interaction with F. oxysporum are likely responsible for filter efficiency. Our results suggest that Pseudomonas spp. act by competition for nutrients, and Bacillus spp. by antibiosis and (or) direct parasitism. Elimination of other fungal pathogens, i.e., Pythium spp., seems to differ from that of Fusarium since both filters demonstrated a high efficacy at the experiment start. Pythium spp. elimination appears to mainly rely on physical factors. It is worth noting that a certain percentage of the 5 pozzolana-inoculated bacteria failed to colonise the filter unit and were, thus, driven to the plants by the nutrient solution. Their contribution to the establishment of a beneficial microbial community in the rhizosphere is discussed.Key words: Pythium spp., Fusarium oxysporum, Bacillus cereus, Pseudomonas putida.
Denitrifying bacteria in bulk and maize-rhizospheric soil: diversity and N2O-reducing abilities
Authors: Chèneby D , Perrez S , Devroe C , Hallet S , Couton Y , Bizouard F , Iuretig G , Germon J C , Philippot L
Published: September 2004

The aim of this study was to determine the effect of the rhizosphere of maize on the diversity of denitrifying bacteria. Community structure comparison was performed by constructing a collection of isolates recovered from bulk and maize planted soil. A total of 3240 nitrate-reducing isolates were obtained and 188 of these isolates were identified as denitrifiers based on their ability to reduce nitrate to N2O or N2. 16S rDNA fragments amplified from the denitrifying isolates were analysed by restriction fragment length polymorphism. Isolates were grouped according to their restriction patterns, and 16S rDNA of representatives from each group were sequenced. A plant dependent enrichment of Agrobacterium-related denitrifiers has been observed resulting in a modification of the structure of the denitrifying community between planted and bulk soil. In addition, the predominant isolates in the rhizosphere soil were not able to reduce N2O while dominant isolates in the bulk soil evolve N2as a denitrification product.Key words: denitrification, diversity, rhizosphere, N2O, maize.
Transfer of a plant chitinase gene into a nitrogen-fixing Azospirillum and study of its expression
Authors: Jayaraj Jayaraman , Muthukrishnan Subbaratnam , Liang George H
Published: September 2004

Azospirillum is used extensively in rice and other cereal crops as a biofertilizer. There is a substantial opportunity to improve the efficiency of this bacterium through the transfer of genes of agricultural importance from other organisms. Chitinases are antifungal proteins, and expression of chitinase genes in Azospirillum would help to develop strains with potential antifungal activities. So far there are no reports about transfer of plant genes into Azospirillum and their expression. The present study was aimed at expressing an antifungal gene (a rice chitinase) of plant origin in Azospirillum brasilense. A rice chitinase cDNA (RC 7) that codes for a 35 kDa protein was subcloned into a broad host range plasmid pDSK519 under the control of LacZ promoter. The plasmid was mobilized into the nitrogen-fixing bacterium, Azospirillum brasilense strain SP51eFL1, through biparental mating. The conjugation frequency was in the range of 35–40 × 10–6. The transconjugants grew in nitrogen-free media and fixed gaseous nitrogen in vitro. However, their growth and nitrogen-fixing ability were slightly less than those of the wild-type. Expression of the protein was demonstrated through western blotting of the total cell protein, which detected a 35 kDa band that was immuno-reactive to a barley chitinase antibody. The cell lysates also hydrolyzed various chitin substrates, which resulted in release of free sugars demonstrating the chitinase activity of transconjugants. The expressed protein also had antifungal activity as demonstrated by inhibition of growth of the plant pathogenic fungus, Rhizoctonia solani.Key words: Azospirillum-transformation, rice chitinase gene, protein expression, chitinase activity.
Mutational analysis of the serotonin receptor 5HT2c in severe early-onset human obesity
Authors: Gibson William T , Ebersole Barbara J , Bhattacharyya Sumit , Clayton Peter , Farooqi I Sadaf , Sealfon Stuart C , O'Rahilly Stephen
Published: September 2004

Deletion of the serotonin receptor 5HT2c in mice results in increased food intake and obesity. We screened 95 individuals with severe early-onset obesity for mutations in the coding sequence of this gene. We found a novel missense variant c.1255A > G (Thr419Ala) in a single Caucasian subject that was not found in 192 Caucasian control subjects. In transiently-transfected COS cells, the Thr419Ala variant was indistinguishable from the wild-type receptor in its ability to generate inositol phosphate, although differences in coupling to other pathways were not excluded. Three previously unreported silent variants: IVS3 + 30G > A, IVS3 + 80C > G and IVS4 – 31A > G were found with prevalences of 11.5%, 0.5% and 17.9%, respectively. In conclusion, mutations in 5HT2c are unlikely to be a common cause of severe early-onset human obesity. The identification of several novel polymorphisms at this locus may aid future genetic epidemiological studies.Key words: G-protein coupled receptor, hyperphagia, obesity, serotonin, X-linked.