Conditional QTL mapping of oil content in rapeseed with respect to protein content and traits related to plant development and grain yield

Oil content in rapeseed (Brassica napus L.) is generally regarded as a character with high heritability that is negatively correlated with protein content and influenced by plant developmental and yield related traits. To evaluate possible genetic interrelationships between these traits and oil content, QTL for oil content were mapped using data on oil content and on oil content conditioned on the putatively interrelated traits. Phenotypic data were evaluated in a segregating doubled haploid population of 282 lines derived from the F(1) of a cross between the old German cultivar Sollux and the Chinese cultivar Gaoyou. The material was tested at four locations, two each in Germany and in China. QTLMapper version 1.0 was used for mapping unconditional and conditional QTL with additive (a) and locus pairs with additive x additive epistatic (aa) effects. Clear evidence was found for a strong genetic relationship between oil and protein content. Six QTL and nine epistatic locus pairs were found, which had pleiotropic effects on both traits. Nevertheless, two QTL were also identified, which control oil content independent from protein content and which could be used in practical breeding programs to increase oil content without affecting seed protein content. In addition, six additional QTL with small effects were only identified in the conditional mapping. Some evidence was apparent for a genetic interrelationship between oil content and the number of seeds per silique but no evidence was found for a genetic relationship between oil content and flowering time, grain filling period or single seed weight. The results indicate that for closely correlated traits conditional QTL mapping can be used to dissect the genetic interrelationship between two traits at the level of individual QTL. Furthermore, conditional QTL mapping can reveal additional QTL with small effects that are undetectable in unconditional mapping.

Comparison of phenotypic and molecular distances to predict heterosis and F1 performance in Ethiopian mustard (Brassica carinata A. Braun)

Predicting heterosis and F1 performance from the parental generation could largely enhance the efficiency of breeding hybrid or synthetic cultivars. This study was undertaken to determine the relationship between parental distances estimated from phenotypic traits or molecular markers with heterosis, F1 performance and general combining ability (GCA) in Ethiopian mustard (Brassica carinata). Nine inbred lines representing seven different geographic regions of Ethiopia were crossed in half-diallel. The nine parents along with their 36 F1s were evaluated in a replicated field trail at three locations in Ethiopia. Distances among the parents were calculated from 14 phenotypic traits (Euclidean distance, ED) and 182 random amplified polymorphic DNA (RAPD) markers (Jaccard's distances, JD), and correlated with heterosis, F1 performance and GCA sum of parents (GCAsum). The correlation between phenotypic and molecular distances was low (r=0.34, P< or =0.05). Parents with low molecular distance also had low phenotypic distance, but parents with high molecular distance had either high, intermediate or low phenotypic distance. Phenotypic distance was highly significantly correlated with mid-parent heterosis (r=0.53), F1 performance (r=0.61) and GCA (r=0.79) for seed yield. Phenotypic distance was also positively correlated with (1) heterosis, F1 performance and GCA for plant height and seeds plant(-1), (2) heterosis for number of pods plant(-1), and (3) F1 performance for 1,000 seed weight. Molecular distance was correlated with GCAsum (r=0.36, P< or =0.05) but not significantly with heterosis and F1 performance for seed yield. For each parent a mean distance was calculated by averaging the distances to the eight other parents. Likewise, mean heterosis was estimated by averaging the heterosis obtained when each parent is crossed with the other eight. For seed yield, both mean ED and JD were significantly correlated with GCA (r=0.90, P< or =0.01 for ED and r=0.68, P< or =0.05 for JD) and mean heterosis (r=0.79, P< or =0.05 for ED and r=0.77, P< or =0.05 for JD). In conclusion, parental distances estimated from phenotypic traits better predicted heterosis, F1 performance and GCA than distances estimated from RAPD markers.

Resveratrol glucoside (Piceid) synthesis in seeds of transgenic oilseed rape (Brassica napus L.)

Resveratrol is a phytoalexin produced in various plants like wine, peanut or pine in response to fungal infection or UV irradiation, but it is absent in members of the Brassicaceae. Moreover, resveratrol and its glucoside (piceid) are considered to have beneficial effects on human health, known to reduce heart disease, arteriosclerosis and cancer mortality. Therefore, the introduction of the gene encoding stilbene synthase for resveratrol production in rapeseed is a tempting approach to improve the quality of rapeseed products. The stilbene synthase gene isolated from grapevine (Vitis vinifera L.) was cloned under control of the seed-specific napin promotor and introduced into rapeseed (Brassica napus L.) by Agrobacterium-mediated co-transformation together with a ds-RNA-interference construct deduced from the sequence of the key enzyme for sinapate ester biosynthesis, UDP-glucose:sinapate glucosyltransferase (BnSGT1), assuming that the suppression of the sinapate ester biosynthesis may increase the resveratrol production in seeds through the increased availability of the precursor 4-coumarate. Resveratrol glucoside (piceid) was produced at levels up to 361 microg/g in the seeds of the primary transformants. This value exceeded by far piceid amounts reported from B. napus expressing VST1 in the wild type sinapine background. There was no significant difference in other important agronomic traits, like oil, protein, fatty acid and glucosinolate content in comparison to the control plants. In the third seed generation, up to 616 microg/g piceid was found in the seeds of a homozygous T3-plant with a single transgene copy integrated. The sinapate ester content in this homozygous T3-plant was reduced from 7.43 to 2.40 mg/g. These results demonstrate how the creation of a novel metabolic sink could divert the synthesis towards the production of piceid rather than sinapate ester, thereby increasing the value of oilseed products.

QTL of three agronomically important traits and their interactions with environment in a European x Chinese rapeseed population

A rapeseed population consisted of 282 doubled haploid (DH) lines derived from a cross between a European vality "Sallux" and a Chinese inbred line "Gaoyou" was planted in 4 locations, 2 in Xi'an and Hangzhou, China, and 2 in Goettingen, Germany. Field experiments were carried out to obtain agronomically phenotypic data from above four environments. A linkage map including 125 SSR-markers was constructed and QTL analyses was performed using mixed model approach to detect QTLs showing additive (a), epistasis (aa) as well as their interactions with environments (QE) for three important agronomic traits: plant height, flowering time and maturity. The results demonstrated that each trait was controlled by several QTLs with additive effect and a number of QTLs with epistatic and QE interaction effects. Plant height was controlled by many QTLs (12 loci with a or combined ae, 5 loci with ae). Additive effects were predominant,totally explained 75% of the phenotypic variation and often combined with digenic epistasis. Of 12 main QTLs, 9 showed Gaoyou alleles decreasing plant height. Most of QTLs with QE effects showed ecologically favourable alleles in diverse regions. Five of 7 ae loci showed Gaoyou alleles in Hangzhou and all the ae loci but one had Sollux alleles in two locations of Germany increasing plant height. The digenic epistatic main effect accounted for one third of total additive main effects. In this study,we discovered 7 and 8 loci having significant additive main effects upon flowering time and maturity, respectively. Of them, early flowering and maturity alleles were respectively 6 and 5 derived from Chinese parent Gaoyou. All these QTLs together accounted for around 60% of the phenotypic variation for each trait. Significant ae interactions were detected for flowering time and maturity and parental alleles showed almost evenly dispersal at all environments. Three of 8 main QTLs for maturity were located at similar or identical positions as QTLs for flowering time, which confirmed the close correlation between these two traits. Two QTLs for plant height on linkage groups N14-1 and 19 were located at similar positions as QTL for flowering time and as already known QTLs for oil content. Selection for reduced plant height and early flowering might reduce oil content. Digenic epistatic QTLs both for flowering time and maturity were detected but much less important than QTLs with additive effects.

Tolerance to the discriminative stimulus effects of ethanol following chronic inhalation exposure to ethanol in C57BL/6J mice

A significant consequence of chronic ethanol (EtOH) exposure is the development of tolerance. The present study was designed to investigate tolerance to the discriminative stimulus properties of EtOH following chronic EtOH exposure. Adult male C57BL/6J mice were trained to discriminate EtOH (1.00 g/kg; i.p.) from saline, using a food-reinforced two-lever operant task. Following acquisition and establishment of criterion discrimination performance, a series of generalization tests were conducted to generate a baseline EtOH dose-response curve with a calculated ED50 dose of 0.42 g/kg. Mice were then placed into control (air) or EtOH inhalation chambers for 64 h. In Experiment 1, discriminative stimulus generalization tests with the EtOH ED50 dose conducted 24 h following chronic EtOH (or air) exposure did not yield significantly different EtOH responding, although a trend towards reduced sensitivity to the EtOH cue (tolerance) was evident. In Experiment 2, a cumulative dosing procedure (ED50=0.37 g/kg) was employed, yielding a baseline EtOH dose-response function with a calculated ED50 dose of 0.37 g/kg. At 24 h following chronic EtOH exposure, re-determination of the EtOH dose-response curve revealed a significant shift to the right, with more than a twofold increase in the ED50 value (ED50=1.09 g/kg) compared to the control air exposure condition (ED50=0.49 g/kg). This apparent tolerance to the EtOH cue dissipated in chronic EtOH-exposed mice tested 48 h following the inhalation treatment (ED50=0.51 g/kg). These results demonstrate tolerance to the discriminative stimulus effects of EtOH in C57BL/6J mice following chronic EtOH exposure in inhalation chambers.

The anticancer drug-DNA complex: femtosecond primary dynamics for anthracycline antibiotics function

The anthracycline-DNA complex, which is a potent agent for cancer chemotherapy, has a unique intercalating molecular structure with preference to the GC bases of DNA, as shown by Rich's group in studies of single-crystal x-ray diffraction. Understanding cytotoxicity and its photoenhancement requires the unraveling of the dynamics under the solution-phase, physiological condition. Here we report our first study of the primary processes of drug function. In a series of experiments involving the drug (daunomycin and adriamycin) in water, the drug-DNA complexes, the complexes with the four nucleotides (dGTP, dATP, dCTP, and dTTP), and the drug-apo riboflavin-binding protein, we show the direct involvement of molecular oxygen and DNA base-drug charge-separation-the rates for the reduction of the drug and dioxygen indicate the crucial role of drug/base/O(2) in the efficient and catalytic redox cycling. These dynamical steps, and the subsequent reactions of the superoxide product(s), can account for the photoenhanced function of the drug in cells, and potentially for the cell death.

Alcohol withdrawal kindling: mechanisms and implications for treatment

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chair was Larry P. Gonzalez. The presentations were (1) EEG indices of sensitization in a murine model of repeated ethanol withdrawals, by Lynn M. Veatch; (2) Long-term changes in central nervous system function after repeated alcohol withdrawals: Recommendations for the treatment of acute withdrawal, by Larry P. Gonzalez; (3) Differential regulation of GABAA and NMDA receptors by repeated ethanol treatment in cultured mammalian neurons, by Maharaj K. Ticku; and (4) Involvement of GABAA and NMDA receptors in alcohol withdrawal kindling: Implications for treatment, by Howard C. Becker.

Animal models of alcohol withdrawal

One diagnostic criterion of alcohol dependence is the appearance of a withdrawal syndrome when alcohol consumption ceases. Researchers have used various animal models, including isolated brain cells, slices of brain tissue, and intact animals, to study the mechanisms and manifestations of withdrawal. Results from these experimental studies have demonstrated that many consequences of withdrawal found in animals resemble those observed in humans. Such signs and symptoms of alcohol withdrawal include enhanced activity of the autonomic nervous system; body posture and motor abnormalities; hyperexcitability of the central nervous system, including sensory hyperreactivity; convulsions; anxiety; and psychological discomfort. Researchers also have used animal models to study the electrophysiological correlates of withdrawal, as well as neurobiological mechanisms underlying alcohol dependence and withdrawal.

Repeated ethanol withdrawal experience selectively alters sensitivity to different chemoconvulsant drugs in mice

Repeated ethanol withdrawal experience has been shown to result in exacerbated seizures associated with future withdrawal episodes. This sensitization of the withdrawal response has been postulated to represent a "kindling" phenomenon. The present study employed an established model of repeated ethanol withdrawals to examine the potential role of GABA(A), and NMDA and non-NMDA glutamate receptor systems in mediating enhanced seizure activity, as assessed by sensitivity to seizures induced by pentylenetetrazol (PTZ), NMDA, and kainic acid (KA) i.v. infusions, respectively. Adult C3H mice were chronically exposed to ethanol vapor in inhalation chambers. A multiple withdrawal (MW) group received four cycles of 16-h ethanol vapor exposure interrupted by 8-h periods of abstinence; a single withdrawal (SW) group was tested after a single 16-h bout of ethanol intoxication; and the third group was ethanol-naive, serving as controls (C). Results indicated that the MW group evidenced significantly lower PTZ and NMDA seizure thresholds compared to SW and C groups at 8 and 24 h post-withdrawal. In contrast, MW and SW groups exhibited reduced sensitivity (higher seizure threshold) to KA in comparison to controls, and this effect only emerged at 24 h post-withdrawal. Further, MW mice required significantly less additional PTZ or NMDA to induce more severe convulsions once initial signs of seizures were elicited. Conversely, latency and amount of KA required to transition from initial seizure signs to more severe end-stage convulsions was significantly greater for MW and SW groups compared to controls. Taken together, these results suggest that repeated ethanol withdrawal experience does not result in a global non-specific lowering of threshold to convulsive stimuli, but rather, selective changes in CNS mechanisms associated with neural excitability may underlie potentiated withdrawal responses. Thus, reduced GABA(A) receptor function and increased NMDA receptor activity may become exaggerated as a consequence of repeated withdrawal experience, while reduced sensitivity to KA induced seizures may represent a compensatory response to withdrawal-related CNS hyperexcitability.

Single and repeated episodes of ethanol withdrawal increase adenosine A1, but not A2A, receptor density in mouse brain

A history of multiple ethanol withdrawal experiences has been shown to exacerbate the severity of future withdrawal episodes, and this sensitization of the withdrawal response has been hypothesized to represent a 'kindling' phenomenon. Since adenosine functions as an inhibitory modulator of seizure activity and may interact with ethanol to influence neuronal excitability, the present study was conducted to examine the effects of single and repeated episodes of ethanol withdrawal on adenosine A1 and A2A receptors in adult C3H/He mice. Mice were chronically exposed to ethanol vapor in inhalation chambers and tested for withdrawal seizures following multiple withdrawal (MW) experience (four cycles of 16 h ethanol intoxication interrupted by 8 h periods of abstinence), single withdrawal experience following 16 h (SW) or 64 h (CE) continuous ethanol intoxication, or no ethanol exposure (controls). Separate groups of mice from each withdrawal condition were used to generate pooled cortical and striatal tissue for ligand saturation experiments using [3H]cyclohexyladenosine to label A1 receptors and [3H]CGS 21680 to label A2A receptors. Results indicated that withdrawal seizures were significantly more severe in mice with multiple withdrawal experience in comparison to animals that experienced only a single withdrawal episode, even when total amount of ethanol exposure was equated among groups. The density of A1 receptors in cerebral cortex was significantly increased over controls 8 h following final ethanol withdrawal by approximately 35% in SW and CE groups, with the largest increase observed in the MW group (56%). Withdrawal treatment groups did not differ in cortical A1 binding sites immediately upon withdrawal from ethanol, and no significant differences in binding of [3H]CGS 21680 to striatal A2A receptors were observed following ethanol withdrawal. Ethanol exposure and withdrawal did not significantly alter ligand affinity for either adenosine receptor. These results indicate that adenosine A1 receptors are selectively upregulated during ethanol withdrawal and that the degree of upregulation may be enhanced following multiple withdrawal episodes. Further, these observations suggest that the upregulation of brain A1 receptors during ethanol withdrawal may represent a compensatory inhibitory response to increased seizure severity associated with repeated episodes of ethanol withdrawal.

Kindling in alcohol withdrawal

In many alcoholics, the severity of withdrawal symptoms increases after repeated withdrawal episodes. This exacerbation may be attributable to a kindling process. Kindling is a phenomenon in which a weak electrical or chemical stimulus, which initially causes no overt behavioral responses, results in the appearance of behavioral effects, such as seizures, when it is administered repeatedly. Both clinical and experimental evidence support the existence of a kindling mechanism during alcohol withdrawal. Withdrawal symptoms, such as seizures, result from neurochemical imbalances in the brain of alcoholics who suddenly reduce or cease alcohol consumption. These imbalances may be exacerbated after repeated withdrawal experiences. The existence of kindling during withdrawal suggests that even patients experiencing mild withdrawal should be treated aggressively to prevent the increase in severity of subsequent withdrawal episodes. Kindling also may contribute to a patient's relapse risk and to alcohol-related brain damage and cognitive impairment.

Repeated ethanol withdrawal experience increases the severity and duration of subsequent withdrawal seizures in mice

Repeated ethanol withdrawal experience has been shown to result in an exacerbation of future withdrawal episodes. This sensitization of the withdrawal response has been hypothesized to represent a "kindling" phenomenon. The present study was designed to examine whether a systematic increase in the number of previous ethanol withdrawal experiences increases both the severity and duration of a subsequent withdrawal response. An established model of repeated ethanol intoxication/withdrawal was employed in which adult C3H mice were chronically exposed to ethanol vapor in inhalation chambers. In the first experiment, multiple withdrawal (MW) groups of mice received nine (MW x 9), six (MW x 6), or three (MW x 3) cycles of 16-h ethanol vapor separated by 8-h periods of abstinence prior to testing: a single withdrawal (SW) group was tested following a single bout of 16-h ethanol exposure; and a control (C) group did not receive any ethanol treatment throughout the experiment. In a second experiment, a group of mice (MW1-9) were repeatedly tested over nine cycles of withdrawal. A third experiment was designed to assess the effects of repeated pyrazole administration on the potentiated withdrawal seizure response. Results indicated a positive relationship between the number of previously experienced ethanol withdrawals and the severity and duration of a subsequent withdrawal episode. Blood ethanol levels were similar for all ethanol-exposed groups prior to withdrawal assessment. Further, the intensity of withdrawal seizures (handling-induced convulsions) progressively increased over nine cycles of intoxication/withdrawal and repeated testing did not significantly influence the development of this potentiated response. In addition, repeated administration of pyrazole did not appear to influence this withdrawal sensitization phenomenon. Collectively, these results provide further support for the "kindling" hypothesis of ethanol withdrawal.

Exacerbation of ethanol withdrawal seizures in mice with a history of multiple withdrawal experience

Repeated ethanol withdrawal experience has been shown to result in an exacerbation of future withdrawal episodes. This sensitization of the withdrawal response has been hypothesized to represent a "kindling" phenomenon. We previously demonstrated that mice exposed to ethanol vapor for a total of 48 h exhibited more severe withdrawal seizures if the exposure was divided into three 16 h intoxication/8 h abstinence cycles than if the 48 h of exposure occurred in a single bout. The present study was designed to further characterize this model of ethanol withdrawal "kindling" and determine whether such a "kindled" response may be evident when withdrawal testing is conducted after an additional bout of intoxication that is the same for all groups. Adult C3H mice were chronically exposed to ethanol vapor in inhalation chambers for 40 h prior to withdrawal testing. Prior to this 40 h intoxication period, one group (Multiple Withdrawal; MW) received three cycles of 16 h ethanol vapor separated by 8 h abstinence; a second group (Single Withdrawal; SW) did not receive any ethanol exposure prior to the 40 h test cycle; a third group (Continuous Exposure; CE) received the same total ethanol exposure as the MW group (48 hr), but without interruption: and a control group (C) did not receive any ethanol treatment throughout the experiment. Blood ethanol levels following the 40 h bout of ethanol intoxication were 100-140 mg/dl for all ethanol-exposed groups. The severity of handling-induced convulsions during withdrawal was significantly greater in the MW group compared to CE and SW groups. These results suggest that differences in the severity of ethanol withdrawal seizures due to differences in prior withdrawal experience can be demonstrated even when later ethanol exposure patterns are equated. As such, the results provide further support for the "kindling" hypothesis of ethanol withdrawal.

Teratogenic actions of ethanol in the mouse: a minireview

The deleterious effects of prenatal ethanol exposure have been extensively documented in clinical and experimental studies. This paper provides an overview of work conducted with mice to examine the myriad of adverse consequences that result from embryonic/fetal exposure to ethanol. All of the hallmark features of the clinical fetal alcohol syndrome have been demonstrated in mice, including prenatal and postnatal growth retardation, structural malformations and behavioral abnormalities associated with central nervous system dysfunction. As expected, the severity and profile of effects is related to both dosage level and timing of exposure. In addition, these effects have been demonstrated following acute and chronic exposure, with a variety of routes of administration employed. Furthermore, a number of strains have been used in these studies and the variant response (susceptibility) to the teratogenic actions of ethanol exhibited among different mouse strains support the notion that genetic factors govern, at least in part, vulnerability to these effects of ethanol. More recent studies using mouse models have focused on examining potential mechanisms underlying the full spectrum of ethanol's teratogenic actions.

Effect of acute ethanol and cocaine administration on gestation days 14-17 in mice

The teratogenic effects of the coadministration of alcohol and cocaine on gestation days 14-17 were investigated using an acute exposure model. Pregnant C57BL/6J mice were assigned randomly to treatment groups generated from a 2 (0 or 6 g/kg alcohol) x 2 (0 or 60 mg/kg cocaine) x 4 (day of treatment) factorial design. An untreated control group was also employed. On GD14, 15, 16, or 17, females were intubated with alcohol or an isocaloric solution and injected (SC) 10 min later with cocaine or saline. Litters were evaluated on GD19 following cesarean delivery. A significant number of females in the alcohol-only group treated on GD16 or GD17 delivered litters prior to GD19. The results indicated that, in general, prenatal alcohol exposure was associated with decreased fetal body weight and suggested a possible increase in malformations of vascular origin. Cocaine and the alcohol/cocaine interaction did not affect the outcome variables in any reliable manner. Thus, with the animal model employed, cocaine did not exert teratogenic effects on its own nor did it influence alcohol-induced teratogenesis.

Chronic ethanol exposure selectively increases diazepam-insensitive [3H]RO15-4513 binding in mouse cerebellum

The effect of chronic ethanol exposure and withdrawal on [3H]RO15-4513 (ethyl-8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5a][1,4] benzodiazepine-3-carboxylate) binding to diazepam-sensitive and diazepam-insensitive binding sites was determined in mouse brain. Neither chronic ethanol treatment nor withdrawal significantly altered total [3H]RO15-4513 binding in mouse cortex or cerebellum. However, diazepam-insensitive [3H]RO15-4513 binding density (Bmax) in cerebellum was significantly increased immediately following chronic ethanol treatment (60%) and at 8 h following withdrawal (75%). [3H]RO15-4513 binding affinity was not significantly influenced by chronic ethanol exposure or withdrawal. These results indicate that chronic ethanol treatment and withdrawal can selectively up-regulate diazepam-insensitive [3H]RO15-4513 binding sites and suggest that this unique GABAA receptor subtype may play some role in ethanol dependence and withdrawal.

Acute gestational cocaine exposure alone or in combination with low-dose ethanol does not influence prenatal mortality or fetal weight in mice

The teratogenic effects of cocaine and ethanol were investigated using an acute treatment model of C57BL/6J mice treated on gestation day 15 (GD15) with evaluation on GD17. Females were intubated once with a subteratogenic dose of ethanol (0 or 4 g/kg) and injected subcutaneously twice, 1 h apart, with equal doses of cocaine HCl (0 or 60 mg/kg), for a final daily dose of 120 mg/kg. The first cocaine injection followed ethanol by 10 min. Blood ethanol levels (BEL) and plasma cocaine levels were determined, and pair-feeding was employed. The results revealed no group differences on pregnancy outcome. That is, maternal weight gain, total number of implants, prenatal mortality, and fetal body weight were not statistically different. No significant differences in BEL or plasma cocaine levels were found among the various treatment groups. These results suggest that, under these conditions, relatively high levels of cocaine (120 mg/kg, SC), given alone or in combination with subteratogenic doses of ethanol late in pregnancy, are not teratogenic in mice.

Comparison of rapeseed cultivars and resynthesized lines based on allozyme and RFLP markers

It has frequently been suggested to use the resynthesis of rapeseed (Brassica napus) from B. campestris and B. oleracea to broaden its genetic base. The objective of the present study is twofold: (1) to compare the genetic variation within resynthesized rapeseed with a world-wide collection of oilseed rape cultivars, and (2) to compare genetic distances estimated from RFLP markers with distances estimated from a relatively small number of allozyme markers. We investigated 17 resynthesized lines and 24 rapeseed cultivars. Genetic distances were estimated either based on the electrophoresis of seven allozymes, with a total of 38 different bands, or based on RFLP data of 51 probe/enzyme combinations, with a total of 355 different bands. The results of allozyme and RFLP analyses agreed reasonably well. Genetic distances, estimated from two independent sets of RFLP data with 25 and 26 probe/enzyme combinations respectively, were highly correlated; hence about 50 RFLP markers are sufficient to characterize rapeseed material with a large genetic diversity. The cultivars were clustered into three groups: (1) spring rapeseed of European and Northern American origin, (2) winter rapeseed of European and Northern American origin, and (3) rapeseed of Asian origin. Several of the resynthesized rapeseed lines were similar to European winter rapeseed cultivars, whereas others had quite unique patterns. It is concluded, that resynthesized rapeseed is a valuable source for broadening the genetic variation in present breeding material of Brassica napus. However, different lines differ widely in their suitability for this purpose.

Prenatal ethanol exposure alters sensitivity to the effects of apomorphine given alone and in combination with ethanol on locomotor activity in adult male mouse offspring

Previous studies have indicated that prenatal ethanol (EtOH) exposure alters developing catecholamine (CA) systems and acute sensitivity to the locomotor stimulant effects of EtOH. The purpose of this study was to examine whether prenatal EtOH exposure influences the effects of the direct dopamine (DA) agonist apomorphine given alone as well as in combination with a low-dose stimulant challenge of EtOH. Standard lab chow or liquid diets containing either 25% EtOH-derived calories (EDC), or 0% EDC were given to pregnant C3H/He mice on gestation days 6-18. At 90 days of age, male offspring from each prenatal treatment group were monitored for 10 min in an open field following IP injections of apomorphine (0, 0.15, 0.3, 0.6, or 1.2 mg/kg) and either EtOH (1.5 g/kg) or saline. EtOH alone increased activity by 120-143% in all three groups of offspring. In control offspring, apomorphine dose-dependently decreased activity up to 74%-78% and blocked the stimulant effect of EtOH at all doses tested. However, in prenatal EtOH-exposed offspring, higher doses of apomorphine were significantly less effective in reducing both baseline and EtOH-stimulated activity compared to control mice. This effect is most likely not due to differences in pharmacokinetics, because blood EtOH concentrations were similar across apomorphine doses and prenatal treatment conditions. As such, these results support the hypothesis that prenatal exposure to EtOH alters acute sensitivity to the locomotor stimulant effects of EtOH, particularly under conditions in which CA systems mediating those effects are additionally challenged. In addition, the results suggest that prenatal EtOH exposure results in a long-lasting perturbation of central DA receptor sensitivity.

Transurethral laser urethrotomy with argon laser: experience with 900 urethrotomies in 450 patients from 1978 to 1993

From April 1978 to September 1993, the Department of Urology of Giessen Medical School used laser urethrotomy as standard endoscopic treatment in benign urethral strictures. In this period, 900 urethrotomies were performed in 450 patients. The majority of strictures treated were iatrogenic (65%), located in the posterior urethra (62.8%) and classified as short (< or = 1 cm) (71%). Argon laser urethrotomy was carried out in the 12 degrees position according to the technique of internal optical urethrotomy. An indwelling transurethral catheter was left for 48 h after urethrotomy. Uroflowmetry after argon laser urethrotomy revealed the efficacy of the method. A retrospective analysis of the operations was performed. Analysis showed that recurrence appeared on average after 15.2 months (range 1-39) in up to 70.1%. Nearly 50% of recurrence was evident within 1 year following surgery. Recurrence was independent of location, length and etiology of the stricture. We conclude according to our data that argon laser urethrotomy is technically feasible. Due to the high recurrence rate the method offers no advantage over conventional internal optical urethrotomy.