Newly isolated Nodularia phage influences cyanobacterial community dynamics.

Cyanophages, that is, viruses infecting cyanobacteria, are a key component driving cyanobacterial community dynamics both ecologically and evolutionarily. In addition to reducing biomass and influencing the genetic diversity of their host populations, they can also have a wider community-level impact due to the release of nutrients by phage-induced cell lysis. In this study, we isolated and characterized a new cyanophage, a siphophage designated as vB_NpeS-2AV2, capable of infecting the filamentous nitrogen fixing cyanobacterium Nodularia sp. AV2 with a lytic cycle between 12 and 18 hours. The role of the phage in the ecology of its host Nodularia and competitor Synechococcus was investigated in a set of microcosm experiments. Initially, phage-induced cell lysis decreased the number of Nodularia cells in the cultures. However, around 18%-27% of the population was resistant against the phage infection. Nitrogen was released from the Nodularia cells as a consequence of phage activity, resulting in a seven-fold increase in Synechococcus cell density. In conclusion, the presence of the cyanophage vB_NpeS-2AV2 altered the ecological dynamics in the cyanobacterial community and induced evolutionary changes in the Nodularia population, causing the evolution from a population dominated by susceptible cells to a population dominated by resistant ones.

Effects of long-term intake of lactotripeptides on cardiovascular risk factors in hypertensive subjects.

BACKGROUND/OBJECTIVES: Lactobacillus helveticus LBK-16H-fermented milk products containing tripeptides isoleucine-proline-proline and valine-proline-proline lower blood pressure in hypertensive subjects using office and home blood pressure registration. The present study was aimed to evaluate the effects of two doses of these lactotripeptides on 24-h ambulatory blood pressure and lipidomics profiles in mildly hypertensive subjects. SUBJECTS/METHODS: In a randomized, double-blind, placebo-controlled parallel group study, 89 mildly hypertensive subjects ingested, after a 1-month run-in period, a fermented milk drink with 5 mg per day of lactotripeptides during 3 months, and a milk drink with 50 mg per day of lactotripeptides for the following 3 months, or a placebo milk drink without lactotripeptides. Ambulatory blood pressure (24 h) was recorded at baseline and at the end of the intervention periods. Lipidomics profiles were characterized before and after the 6-month intervention. RESULTS: After the second intervention period (50 mg per day of lactotripeptides), systolic and diastolic 24-h blood pressures decreased significantly in the peptide, but not in the placebo group. However, the treatment effects -2.6 mm Hg (95% confidence interval (CI): -5.7 to 0.4) in systolic and -1.3 mm Hg (95% CI: -3.4 to 0.8) in diastolic blood pressure did not reach statistic significance. Ingestion of 5 mg per day of lactotripeptides for 3 months did not lower blood pressure. The peptide group was dominated by decrease in multiple phospholipids (PL). CONCLUSIONS: Ingestion of fermented milk with daily dose of 50 mg of lactotripeptides appears to lower elevated blood pressure slightly from the baseline, but not significantly compared with the placebo group and to induce significant decreases in multiple PL.

Integrated model for providing tactical emergency medicine support (TEMS): analysis of 120 tactical situations.

BACKGROUND: Various models for organising tactical emergency medicine support (TEMS) in law enforcement operations exist. In Helsinki, TEMS is organised as an integral part of emergency medical service (EMS) and applied in hostage, siege, bomb threat and crowd control situations and in other tactical situations after police request. Our aim was to analyse TEMS operations, patient profile, and the level of on-site care provided. METHODS: We conducted a retrospective cohort study of TEMS operations in Helsinki from 2004 to 2009. Data were retrieved from EMS, hospital and dispatching centre files and from TEMS reports. RESULTS: One hundred twenty TEMS operations were analysed. Median time from dispatching to arrival on scene was 10 min [Interquartile Range (IQR) 7-14]. Median duration of operations was 41 min (IQR 19-63). Standby was the only activity in 72 operations, four patients were dead on arrival, 16 requests were called off en route and patient examination or care was needed in 28 operations. Twenty-eight patients (records retrieved) were alive on arrival and were classified as trauma (n = 12) or medical (n = 16). Of traumas, two sustained a gunshot wound, one sustained a penetrating abdominal wound, three sustained medium severity injuries and nine sustained minor injuries. There was neither on-scene nor in-hospital mortality among patients who were alive on arrival. The level of on-site care performed was basic life support in all cases. CONCLUSIONS: The results showed that TEMS integrated to daily EMS services including safe zone working only was a feasible, rapid and efficient way to provide medical support to law enforcement operations.

Pulsed-resource dynamics increase the asymmetry of antagonistic coevolution between a predatory protist and a prey bacterium.

Temporal resource fluctuations could affect the strength of antagonistic coevolution through population dynamics and costs of adaptation. We studied this by coevolving the prey bacterium Serratia marcescens with the predatory protozoa Tetrahymena thermophila in constant and pulsed-resource environments for approximately 1300 prey generations. Consistent with arms race theory, the prey evolved to be more defended, whereas the predator evolved to be more efficient in consuming the bacteria. Coevolutionary adaptations were costly in terms of reduced prey growth in resource-limited conditions and less efficient predator growth on nonliving resource medium. However, no differences in mean coevolutionary changes or adaptive costs were observed between environments, even though resource pulses increased fluctuations and mean densities of coevolving predator populations. Interestingly, a surface-associated prey defence mechanism (bacterial biofilm), to which predators were probably unable to counter-adapt, evolved to be stronger in pulsed-resource environment. These results suggest that temporal resource fluctuations can increase the asymmetry of antagonistic coevolution by imposing stronger selection on one of the interacting species.

Analysis of multiple casualty incidents - a prospective cohort study.

BACKGROUND: Our aim was to report the rate and causes for multiple casualty incidents (MCI) to analyse the prehospital part of responding to MCIs, report mortality and find areas for improvement. METHODS: A prospective cohort study conducted in an urban emergency medical service (EMS) between 1.3.1998 and 28.2.2004. RESULTS: Fifty-nine MCIs involving 263 patients (167 walking, 96 non-walking) occurred. The incidence of MCIs was 1.8/100,000 inhabitants year(-1). Traffic accidents were the most common cause followed by residential fires, intoxications and stabbings or shootings. Early MCI alarm by the dispatching centre was performed in 18 MCIs. Deviations from standard emergency medical care occurred in 12% of patients. Lack of immobilization of the neck or back in trauma patients and lack of administration of 100% oxygen in suspected carbon monoxide intoxication were the most common deviations. Deviations were related to the lack of presence of on-scene medical command (P = 0.0013) and inadequate resources (P = 0.0342). One hundred and ninety-two patients were transported to emergency departments. Mortality during the prehospital phase was 4.9% (13/263) and during the next 28 days 2.3% (6/263). Adequate resources for safe and effective management of a MCI were related to an early MCI alarm by the dispatching centre (P = 0,022) and to the presence of on-scene medical command (P < 0,001). CONCLUSIONS: Traffic accidents, residential fires and intoxications were the leading causes for MCIs. Emergency medical service could respond to most MCIs efficiently and safely. Majority of deviations from standard medical care seemed potentially preventable. Several areas for improvement were identified. From prehospital links, the dispatching centre and on-scene medical command had a vital role in the successful management of MCIs.

Rabbit atherosclerotic lesions express scavenger receptor AIII mRNA, a naturally occurring splice variant that encodes a non-functional, dominant negative form of the macrophage scavenger receptor.

Macrophage class A scavenger receptor types I and II (SR-AI and II) mediate the uptake of oxidized LDL in atherosclerotic lesions. The recently described type III receptor (SR-AIII), which lacks amino acids encoded by exon 10 of the SR-A gene, is unable to mediate the uptake of ligands and acts as a dominant negative regulator in the trimeric SR-A molecule. To find out whether SR-AIII might play a role in the regulation of SR-A activity in the arterial wall, we studied its expression in normal and atherosclerotic aortic intima-medias of Watanabe heritable hyperlipidemic (WHHL) and cholesterol-fed New Zealand white (NZW) rabbits. SR-A mRNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR) with a SR-AIII-specific primer pair and with a primer pair suitable for both SR-AI and III. Very low SR-AI expression and no SR-AIII expression was found in the lesion-free aortic intima-medias of WHHL rabbits and control NZW rabbits. WHHL rabbit fatty streaks contained abundant SR-AI expression and low-level SR-AIII expression. In contrast, the numerous fatty streaks and fatty plaques appearing in the aortas of cholesterol-fed (14 weeks) NZW rabbits, and the fatty plaques of WHHL rabbits contained clearly detectable SR-AIII expression in addition to the abundant SR-AI expression. In addition, SR-AIII mRNA was detected in NZW and WHHL rabbit livers. The results suggest that in advanced atherosclerotic lesions, cells may protect themselves from the excessive uptake of oxidized lipoproteins by generating SR-A molecules which cannot bind modified LDL.

677 C-->T polymorphism of the methylenetetrahydrofolate reductase gene and preeclampsia.

OBJECTIVE: To evaluate C to T substitution at nucleotide 677 of N(5), N(10)-methylenetetrahydrofolate reductase gene in women with prior preeclamptic or normotensive pregnancies. METHODS: Methylenetetrahydrofolate reductase genotypes were determined in 113 Finnish women with preeclamptic first pregnancies and 103 controls with one or more normotensive pregnancies, using polymerase chain reaction and restriction enzyme analysis. Preeclampsia was defined as severe in 100 women who fulfilled one or more of the subsequent criteria: systolic blood pressure (BP) at least 160 mmHg, diastolic BP at least 110 mmHg, or proteinuria at least 2 g per 24-hour urine collection. RESULTS: There were no significant differences in prevalences of the methylenetetrahydrofolate reductase genotypes (CC, CT, and TT) between groups (57%, 40%, and 3% in the preeclamptic group and 54%, 39%, and 7%, respectively, in controls). The frequency of the T677 allele was 0.23 in the preeclamptic group and 0.26 in the control group (difference 0.03; 95% confidence interval -0.08, 0.14; P =.51). Our sample had 60% power to detect a difference of the allele frequencies similar to that (0.12) reported previously. The result was similar when analysis was restricted to patients with severe preeclampsia (T677 allele frequency 0.22). CONCLUSION: A carrier status for the T677 allele of the methylenetetrahydrofolate reductase gene does not predispose to preeclampsia, at least in the Finnish population.

Relationship of angiotensin-converting enzyme gene polymorphism to carotid wall thickness in middle-aged men.

The insertion/deletion (I/D) polymorphism of the human angiotensin-converting enzyme (ACE) gene is a major determinant of circulating ACE levels. The D allele has been suggested to be a potent risk factor for coronary artery disease; however, the effect of the ACE gene on carotid atherosclerosis remains controversial. We therefore studied the relationship between the ACE gene I/D polymorphism and carotid artery intima-media thickness (IMT). A random sample of 300 men aged 50-59 years living in southern Finland were selected, and 233 agreed to participate (74%). Data were collected in 219 subjects. Quantitative B-mode ultrasonography was used to measure the maximum near and far wall IMT of right and left common, bifurcation, and internal carotid artery. The mean maximum IMT (overall mean) was calculated as the mean of 12 maximum IMTs at 12 standard sites. Patients with an IMT higher than 1.7 mm in at least one of 12 standard sites were assumed to have carotid atherosclerosis. The I/D polymorphism was determined by polymerase chain reaction. Overestimation of the frequency of the DD genotype was eliminated by insertion-specific primer and the inclusion of 5% dimethylsulfoxide. No significant differences were found in carotid wall thickness between the three genotypes; the overall mean IMT were 1.18 +/- 0.30, 1.22 +/- 0.24, and 1.08 +/- 0.40 mm in genotypes of II, ID, and DD, respectively. Similarly, the ACE genotypes and allele frequencies did not differ significantly between the subjects with and those without carotid atherosclerosis. There was no association in the subgroups among only nonsmoking subjects or subjects without chronic medication. The present data indicate that the I/D polymorphism of the ACE gene is not related to carotid IMT and is unlikely to play a major role in carotid atherosclerosis.

Angiotensin-converting enzyme gene polymorphism is associated with coronary heart disease in non-insulin-dependent diabetic patients evaluated for 9 years.

The insertion/deletion (I/D) polymorphism of the human angiotensin-converting enzyme (ACE) gene is a major determinant of circulating ACE levels. Recent studies have found the ACE D allele to be associated with an increased risk for coronary heart disease (CHD) in diabetic and nondiabetic subjects. This association has not been evaluated in prospective studies. We therefore studied the relationship between ACE gene I/D polymorphism and CHD in patients with non-insulin-dependent diabetes mellitus (NIDDM) evaluated for 9 years. The I/D polymorphism was determined by polymerase chain reaction (PCR). Overestimation of the frequency of the DD genotype was eliminated by insertion-specific primers and inclusion of 5% dimethylsulfoxide (DMSO). Eighty-three patients were evaluated for a mean period of 9.1 years (range, 7.4 to 10.5). Among them, 64 patients showed no CHD at entry. During the follow-up period, 21 patients (37.5%) developed CHD. The systolic blood pressure (P = .046), fasting blood glucose (P < .01), and prevalence of hypertension (P < .001) increased, while high-density lipoprotein (HDL) cholesterol (P < .001) decreased. Patients who developed CHD were older than those who did not; the mean age was 59.3 and 53.2 years, respectively (P = .003). The prevalence of albuminuria at follow-up examination was higher in CHD subjects versus non-CHD subjects (61.9% v 20.9%, P = .012). The D allele of the ACE gene was significantly more frequent in subjects with CHD versus those without CHD in both follow-up (P = .028, chi2 test) and cross-sectional (P = .033, chi2 test) settings. No difference could be detected between the three genotypes in age, body mass index (BMI), blood pressure, or plasma lipid levels. In our logistic regression analysis, the best model selected the DD genotype (P = .0105) and age (P = .0407) as significant risk factors for CHD. This model classified 89% of the subjects correctly. In conclusion, this 9-year prospective study supports the hypothesis that the ACE I/D polymorphism is an important and independent risk factor for CHD in patients with NIDDM.

Angiotensin-converting enzyme insertion/deletion polymorphism and diabetic albuminuria in patients with NIDDM followed Up for 9 years.

Nephropathy is a major cause of premature morbidity and mortality in patients with non-insulin-dependent diabetes mellitus (NIDDM). The insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) is a genetic determinant of plasma ACE levels. Recent studies have found I/D polymorphism of the ACE gene to be associated with nephropathy in NIDDM. This association has not been evaluated in prospective studies. We, therefore, studied the relationship between ACE gene I/D polymorphism and diabetic albuminuria and glomerular filtration rate (GFR) in 83 NIDDM patients followed up for 9 years. At baseline, 29% (24 of 83) of the diabetic patients had an increased (>30 mg/24 h) urinary albumin excretion rate (UAER) and the prevalence of albuminuria at the 9-year examination was 35% (29 of 83). During the follow-up period, systolic blood pressure (p = 0.044), prevalence of hypertension (p < 0.01), and fasting blood glucose levels (p < 0.01) increased, while high-density lipoprotein cholesterol (p < 0.01) decreased. The declines of GFR during the follow-up period were 8.5, 14.1, and 16.3% within genotype groups of II, ID, and DD, respectively (p values for decreases: NS for II, <0.001 for ID, and <0.001 for DD). Patients with the DD genotype tended to have a steeper decrease of GFR, but the change was not statistically significant between the genotype groups. The increases of UAER during the follow-up period were 35.1, 8.3, and 122.4% within genotype groups of II, ID, and DD, respectively, but p values for all increases were not significant. Parallel to GFR, patients with the DD genotype tended to have a steeper increase of UAER, but the change was not statistically significant between the genotype groups. There were no differences in the ACE genotype distribution and allele frequencies between the patients with or without albuminuria either at follow-up or in cross-sectional settings. In conclusion, this 9-year follow-up study does not support the hypothesis that the ACE I/D polymorphism is a major genetic marker of diabetic nephropathy in NIDDM patients.

Expression of lipoprotein receptors in atherosclerotic lesions.

Atherosclerosis is characterized by the presence of lipid-loaded cells which are derived from macrophages and smooth muscle cells. Several lipoprotein receptors may be involved in cellular lipid uptake. These receptors include: scavenger receptor(s); LDL receptor-related protein/alpha2-macroglobulin receptor (LRP); LDL receptor; and VLDL receptor. With the exception of the LDL receptor, all of these receptors are expressed in atherosclerotic lesions. While scavenger receptors are mostly expressed in macrophages, the LRP and VLDL receptor may play an important role in mediating lipid uptake in smooth muscle cells. It is evident that no single receptor pathway is solely responsible for the increased lipid uptake in lesion cells but several redundant mechanisms may contribute to the uptake and degradation of lipoproteins in atherosclerotic lesions.

Relationship of the angiotensin-converting enzyme gene polymorphism to glucose intolerance, insulin resistance, and hypertension in NIDDM.

The deletion (D) allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been shown to be associated with cardiovascular and renal diseases in diabetes mellitus, but the mechanism underlying this association is not known. In addition, recent studies of the effect of the ACE gene on blood pressure have yielded conflicting results. Therefore, we studied the association of the ACE gene I/D polymorphism with glucose intolerance and insulin resistance, and the contribution of this locus to genetic susceptibility to hypertension in non-insulin-dependent diabetic mellitus (NIDDM). We analysed the ACE genotype in 84 unrelated NIDDM patients with a known disease duration of less than 1 year and in 115 age- and sex-matched controls. The I/D polymorphism was determined by the polymerase chain reaction. There were no differences in ACE genotype distribution and allele frequencies between patients with NIDDM and nondiabetic controls. The frequencies of the D and I alleles in both groups were identical, viz., 0.65 and 0.35, respectively. The NIDDM patients with the DD genotype had significantly higher blood glucose levels in the oral glucose tolerance test than those with the other genotypes; the incremental glucose area under the curve in the order of II, ID, and DD was 7.2+/-2.4, 9.2+/-4.0, and 10.7+/-2.7 mmol/l x h (II vs ID vs DD, P=0.0066 by ANOVA). No significant difference was found between the ACE genotype and serum insulin values. Similarly, there were no differences in body mass index, blood pressure, or serum lipids between the three genotypes. Among the non-diabetic controls, there was no statistically significant association of the I/D polymorphism with serum lipids, blood glucose levels, serum insulin concentrations, or blood pressure values. In conclusion, NIDDM patients with the DD genotype have higher blood glucose levels and are more glucose intolerant; this may help to explain the reported association between the D allele and vascular complications in NIDDM.

Expression of LDL receptor, VLDL receptor, LDL receptor-related protein, and scavenger receptor in rabbit atherosclerotic lesions: marked induction of scavenger receptor and VLDL receptor expression during lesion development.

BACKGROUND: Atherosclerotic lesions contain foam cells that arise from monocyte-macrophages and smooth muscle cells (SMCs) by excessive uptake of lipoproteins. There are many candidate receptors for the lipid accumulation, such as LDL receptor (LDLR), VLDL receptor (VLDLR), LDL receptor-related protein (LRP), and scavenger receptors (SRs). However, little quantitative information exists on the expression of these receptors in normal and atherosclerotic arteries. METHODS AND RESULTS: Competitive reverse transcription-polymerase chain reaction and in situ hybridization were used for the studies in New Zealand White (NZW) and Watanabe heritable hyperlipidemic (WHHL) rabbit aortic intima-medias. NZW rabbits were fed a 1% cholesterol diet for 0 (control group), 3, 6, or 14 weeks. LDLR mRNA expression was low in aortic intima-medias of all groups. Of the analyzed receptors, LRP had the highest expression in the control group, and its mRNA was induced threefold in the 14-week group, the aortas of which had extensive lesions. SR expression was low and VLDLR expression moderate in the control group. Both receptors were highly induced during cholesterol feeding (SRs, 3-fold and 270-fold induction; VLDLR, 15-fold and 100-fold induction in the 3-week and 14-week groups, respectively). Comparable results were obtained from WHHL rabbits: high basal LRP mRNA in normal intima-medias; moderate induction of LRP and marked induction of SRs and VLDLR in fatty streaks and fatty plaques. In situ hybridization indicated that LRP and VLDLR were expressed in SMCs and macrophages. VLDLR expression was also observed in endothelial cells. SR expression was detected only in macrophages. CONCLUSIONS: SR and VLDLR mRNAs were highly induced in atherosclerotic lesions. VLDLR and LRP may be involved in the formation of both SMC-and macrophage-derived foam cells, whereas SRs play an important role in lipid uptake in macrophages.

Expression of extracellular SOD and iNOS in macrophages and smooth muscle cells in human and rabbit atherosclerotic lesions: colocalization with epitopes characteristic of oxidized LDL and peroxynitrite-modified proteins.

Oxidative processes play an important role in atherogenesis. Because superoxide anion and nitric oxide (NO) are important mediators in vascular pathology, we studied the expression of extracellular superoxide dismutase (EC-SOD) and inducible nitric oxide synthase (iNOS) in human and rabbit atherosclerotic lesions by using simultaneous in situ hybridization and immunocytochemistry and EC-SOD enzyme activity measurements. We also analyzed the presence in the arterial wall of oxidized lipoproteins and peroxynitrite-modified proteins as indicators of oxidative damage and possible mediators in vascular pathology. EC-SOD and iNOS mRNA and protein were expressed in smooth muscle cells and macrophages in early and advanced lesions. The expression of both enzymes was especially prominent in macrophages. As measured by enzyme activity, EC-SOD was the major SOD isoenzyme in the arterial wall. EC-SOD activity was higher in highly cellular rabbit lesions but lower in advanced, connective tissue-rich human lesions. Despite the abundant expression of EC-SOD, malondialdehyde-lysine and hydroxynonenal-lysine epitopes characteristic of oxidized lipoproteins and nitrotyrosine residues characteristic of peroxynitrite-modified proteins were detected in iNOS-positive, macrophage-rich lesions, thus implying that malondialdehyde, hydroxynonenal, and peroxynitrite are important mediators of oxidative damage. We conclude that EC-SOD, iNOS, and the balance between NO and superoxide anion play important roles in atherogenesis. EC-SOD and iNOS are highly expressed in lesion macrophages. High EC-SOD expression in the arterial wall may be required not only to prevent deleterious effects of superoxide anion but also to preserve NO activity and prevent peroxynitrite formation. Modulation of arterial EC-SOD and iNOS activities could provide means to protect arteries against atherosclerotic vascular disease.

Expression or emotional-motivational connotations with a one-word utterance.

The expression of "naming," "commanding," "angry," "frightened," "pleading," "astonished," "satisfied," "admiring," "scornful," and "sad" was with the word [saara] spoken by 12 subjects. Using the same connotations, the 120 utterances were categorized by 73 listeners. Most samples were agreed on by 50%-99% of the judges. Most samples of "astonished," "angry," "frightened," and "commanding" were judged as intended, while "pleading" was often confused with "sad," and "content" with "admiring." Acoustic differences between the categories were examined for F0, duration, and sound pressure; spectral features of [aa] were visualized with the self-organizing map of Kohonen. Most intraspeaker variation of mean F0, FO range, sound pressure, and duration took place during the [aa] segment. Peak sound pressure, mean FO, and spectral energy distribution of [aa] differentiated among "commanding," "angry," "frightened," "naming," and "sad.". Specific intonations of the [aa] segment were encountered for "astonished," "scornful," and "pleading.". The best-conveyed "admiring" samples were distinguished from "content" by spectral cues for a breathy voice quality.

Categorization of voice disorders with six perceptual dimensions.

To obtain a perceptual reference for acoustic feature selection, 94 male and 124 female voices were categorized using the ratings of 6 clinicians on visual analog scales for pathology, roughness, breathiness, strain, asthenia, and pitch. Partial correlations showed that breathiness and roughness were the main determinants of pathology. The six-dimensional ratings (the six median scores for each voice) were categorized with the aid of the Sammon map and the self-organizing map. The five categories created differed with respect to the breathiness/roughness ratio and the degree of pathology.

Cul-de-sac hypernasality test with pattern recognition of LPC indices.

Acoustic differences between samples of [i], [u], and [a] uttered in nose-open and nose-obstructed condition were studied in 6 women with isolated cleft palate and pathological nasalance scores and 9 healthy women with normal nasalance scores. The speech samples were depicted by 14-component vocal tract area feature vectors obtained by linear prediction and the differences between the samples were studied with a self-organized feature map. Each location on the map corresponds to a certain signal pattern, neighboring locations to similar patterns. The group of healthy subjects differed from the patients for vowels [i] and [u] but not for [a]. In the patients the nose obstruction induced a significant change in the location of these vowel samples on the map. In healthy subjects no such changes were detected. The results agreed with perceived differences between the subjects.

Induction of 15-lipoxygenase mRNA and protein in early atherosclerotic lesions.

BACKGROUND: 15-Lipoxygenase (15-LO) may be involved in atherogenesis and in oxidative modification of LDL. In this study, we investigated 15-LO expression in developing atherosclerotic lesions and verified the exact type of the atherosclerosis-associated LO at the nucleotide level. METHODS AND RESULTS: Quantitative reverse transcription-polymerase chain reaction, in situ hybridization, and immunocytochemistry were used in two models of experimental atherosclerosis. New Zealand White rabbits were given a 1% cholesterol diet for 0 (control group), 3, 6, or 14 weeks. 15-LO mRNA was undetectable in the aortic intima-medias of the control group, whereas it was clearly induced as early as after 3 weeks. 15-LO expression increased further in the 6- and 14-week groups. According to in situ hybridization and immunocytochemical studies, 15-LO was localized to macrophagerich areas. In Watanabe heritable hyperlipidemic rabbits, 15-LO mRNA was undetectable in normal aortic intima-medias. 15-LO mRNA was markedly induced in fatty streaks but less so in more advanced lesions. Identification of the induced LO as reticulocyte-type 15-LO was done by cloning and sequencing. We also observed a distinct basal expression of copper-zinc and extracellular superoxide dismutases in normal aortic intima-medias, but no clear induction of these mRNAs was detected in atherosclerotic aortas. CONCLUSIONS: The results show that, in contrast to copper-zinc and extracellular superoxide dismutases, the expression of reticulocyte-type 15-LO is markedly induced in rabbit fatty streaks. This may lead to an increase in the oxidative potential during the early phase of atherogenesis and contribute to the development of atherosclerotic lesions.