Sensitivity and selectivity of neurons in the medial region of the olfactory bulb to skin extract from conspecifics in crucian carp,Carassius carassius

To examine the functional subdivision of the teleost olfactory bulb, extracellular recordings were made from the posterior part of the medial region of the olfactory bulb in the crucian carp, Carassius carassius. Bulbar units classified as type I or type II were frequently and simultaneously encountered at a recording site. Type I units displayed a diphasic action potential (AP) with a relatively small amplitude, a short duration (rise time approximately 1 ms) and high spontaneous activity (2.5 per s). Type II units exhibited an AP with a rise time of approximately 1.8 ms and low spontaneous activity (1.5 per s). The AP of this latter unit was nearly always followed by a slow potential, a characteristic diphasic wave with a rise time of approximately 5 ms. Chemical stimulation of the olfactory organ with a graded series of conspecific skin extract induced an increased firing of the type I units. During the period of increased activity of the type I units, the activity of the type II units was suppressed. Stimulation with nucleotides, amino acids and taurolithocholic acid did not induce firing of the type I units of the posterior part of the medial region of the olfactory bulb. These results indicate that the posterior part of the medial region of the olfactory bulb is both sensitive to and selective for skin extract from conspecifics, which has been shown to be a potent stimulus inducing alarm behaviour. The results of the present study indicate that recording single unit activity from a particular region of the olfactory bulb is a suitable method for isolating pheromones or other chemical signals that induce specific activity in the olfactory system. The projection of the neurons categorized as type II was determined by antidromic activation of their axons by electrical stimulation applied to the medial bundle of the medial olfactory tract. The anatomical basis of the type I and type II units in the fish olfactory bulb is discussed.     

Ethidium monoazide for DNA-based differentiation of viable and dead bacteria by 5'-nuclease PCR

PCR techniques have significantly improved the detection and identification of bacterial pathogens. Even so, the lack of differentiation between DNA from viable and dead cells is one of the major challenges for diagnostic DNA-based methods. Certain nucleic acid-binding dyes can selectively enter dead bacteria and subsequently be covalently linked to DNA. Ethidium monoazide (EMA) is a DNA intercalating dye that enters bacteria with damaged membranes. This dye can be covalently linked to DNA by photoactivation. Our goal was to utilize the irreversible binding of photoactivated EMA to DNA to inhibit the PCR of DNA from dead bacteria. Quantitative 5'-nuclease PCR assays were used to measure the effect of EMA. The conclusion from the experiments was that EMA covalently bound to DNA inhibited the 5'-nuclease PCR. The maximum inhibition of PCR on pure DNA cross-linked with EMA gave a signal reduction of approximately -4.5 log units relative to untreated DNA. The viable/dead differentiation with the EMA method was evaluated through comparison with BacLight staining (microscopic examination) and plate counts. The EMA and BacLight methods gave corresponding results for all bacteria and conditions tested. Furthermore, we obtained a high correlation between plate counts and the EMA results for bacteria killed with ethanol, benzalkonium chloride (disinfectant), or exposure to 70 degrees C. However, for bacteria exposed to 100 degrees C, the number of viable cells recovered by plating was lower than the detection limit with the EMA method. In conclusion, the EMA method is promising for DNA-based differentiation between viable and dead bacteria.     

Photo-induced arousal response by hornets

When an Oriental hornet Vespa orientalis is subjected to ether anesthesia and then exposed to ultraviolet A light (UVAL) (at a wavelength of 366 nm), it commences showing signs of awakening by starting to move its limbs. While in the process of waking the voltage on its body surface surges sharply from 17-180 mV (median = 71.0) to a level of 93-570 mV (median = 327.5). This elevated level is maintained for several minutes but subsequently drops sharply to starting level. The increase in voltage is throughout accompanied by fluttering of the wings and movements of the legs, as well as attempts to extricate itself from the bindings to the electrodes. These movements by the awakening hornet persist for several minutes even after the irradiation source is turned off but shortly after the switch-off the hornet lapses into sleep again. The described scenario is generally similar in worker, queen and drone hornets, and may even occur in decapitated specimens. The same type of awakening can be repeated in the same fashion after a while, but then the increase in voltage will be smaller than the first time. Continuous UV irradiation of an anesthetized hornet results in a generalized and protracted awakening which, however, is significantly shorter than in a hornet left anesthetized in the dark.     

Genetic polymorphism and sequence evolution of an alternatively spliced exon of the glial fibrillary acidic protein gene,GFAP

Isoform GFAPepsilon of the human cytoskeletal protein GFAP carries, as the result of alternative splicing of exon 7a of GFAP, a novel 42-amino-acid-long C-terminal region with binding capacity for the presenilin proteins. Here we show that exon 7a is present in a variety of mammals but absent from GFAP of chicken and fish. Comparison of the mouse and human GFAP exons showed an increased rate of nonsynonymous nucleotide substitutions in exon 7a compared to the other exons. This resulted in 10 nonconservative and 2 conservative amino acid substitutions and suggests that exon 7a has evolved under different functional constraints. Exons 7a of humans and higher primates are 100% identical apart from alanine codon 426, which is conserved in only 9% of the human alleles, while 21 and 70% of the alleles, respectively, have a valine or a threonine codon at that position. Threonine represents a potential phosphorylation site, and positive selection of that effect could explain the high allele frequency.     

Benzoquinone derivatives of Myrsine africana and Maesa lanceolata

The fruits of Myrsine africana afforded two new benzoquinone derivatives, methylvilangin and methylanhydrovilangin. On the other hand, from the fruits of Maesa lanceolata two more novel compounds; 2,5-dihydroxy-3-(nonadec-14-enyl)-benzoquinone and lanciaquinone were isolated. Their structural elucidation was achieved by spectroscopic measurements including 2D NMR experiments.     

The Danish Registry for Plastic Surgery of the Breast: establishment of a nationwide registry for prospective follow-up,quality assessment,and investigation of breast surgery

Although numerous epidemiologic studies have examined the long-term safety of silicone breast implants during the past decade, there is a relative lack of surveillance data on short-term health effects and complications following cosmetic surgery of the breast. The Danish Registry for Plastic Surgery of the Breast, established in May of 1999, provides plastic surgeons with a nationwide system for the collection of preoperative, perioperative, and postoperative data on women undergoing breast implantation, breast reduction, or mastopexy. The purpose of the Registry is to examine short-term and, eventually, long-term local complications and possible health effects, and to contribute to an ongoing evaluation of surgical results and surveillance of the products. Furthermore, the Registry will allow the identification of new areas for research into cosmetic and reconstructive breast surgery. Women accepting registration in the Danish Registry for Plastic Surgery of the Breast complete a self-administered questionnaire focusing on medical history and demographic and behavioral factors. Preoperative blood samples are drawn for storage. Surgical data, postoperative results, and complications are registered following surgery and at postoperative visits. Currently, registration has been initiated at 24 private and public clinics, representing more than 80 percent of the plastic surgery clinics in Denmark. As of November of 2001, a total of 1472 women with breast implants and 560 women with breast reduction were included in the Registry. These figures are expected to increase annually by 1000 women undergoing breast implantation and 500 women undergoing breast reduction or mastopexy. The authors present their experience of establishing the first nationwide comprehensive clinical-epidemiologic database and biological bank for cosmetic and reconstructive surgery procedures.     

Inhibition of LDL oxidation by flavonoids in relation to their structure and calculated enthalpy

Twenty flavonoid compounds of five different subclasses were selected, and the relationship of their structure to the inhibition of low-density lipoprotein (LDL) oxidation in vitro was investigated. The most effective inhibitors, by either copper ion or 2,2'-azobis (2-amidino-propane) dihydrochloride (AAPH) induction, were flavonols and/or flavonoids with two adjacent hydroxyl groups at ring B. In the presence of the later catechol group, the contribution of the double bond and the carbonyl group at ring C was negligible. Isoflavonoids were more effective inhibitors than other flavonoid subclasses with similar structure. Substituting ring B with hydroxyl group(s) at 2' position resulted in a significantly higher inhibitory effect than by substituting ring A or ring B at other positions. The type of LDL inducer had no effect in flavonoids with catechol structure. Calculated heat of formation data (deltadeltaH(f)) revealed that the donation of a hydrogen atom from position 3 was the most likely result, followed by that of a hydroxyl from ring B. Position 3 was favored only in the presence of conjugated double bonds between ring A to ring B. This study makes it possible to assign the contribution of different functional groups among the flavonoid subclasses to in vitro inhibition of LDL oxidation.     

Acylated flavone glycosides from Veronica

A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two unusual allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-rhamnopyranosyl(1"'-->2")[6"-O-acetyl-beta-glucopyranoside] and 6-hydroxyluteolin 7-O-(6"-O-(E)-caffeoyl)-beta-glucopyranoside, respectively. Isoscutellarein 7-O-(6"'-O-acetyl)-beta-allopyranosyl(1"'-->2")-beta-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete 1H and 13C NMR spectral assignments are presented for both isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens.     

Anti-glucocorticoid effects of progesterone in vivo on rat adipose tissue metabolism

Steroid hormones seem to be important for adipose tissue metabolism and accumulation. As progesterone has been suggested to modulate the glucocorticoid effects, the interactions between glucocortioid and progesterone on adipose tissue metabolism were investigated.Forty-eight male Wistar rats were adrenectomized and divided into four groups; controls (treated with vehicle only), dexamethasone treated (10 micro g per rat), progesterone treated (5mg per rat) and the last group received both dexamethasone and progesterone.The dexamethasone-treated group had a significant loss of body weight and smaller intra-abdominal fat depots compared to the control group in addition, dexamethasone increased LPL-activity and increased catecholamine stimulated lipolysis. When progesterone was given concomitantly the dexamethasone effects on adipose tissue mass, LPL-activity and lipolysis were blocked. When given alone progesterone had no influence on body weight, amount of adipose tissue, lipolysis or LPL-activity.These data indicate that progesterone acts as an anti-glucocorticoid in adipose tissue in vivo, thus attenuating the glucocorticoid effect on adipose tissue metabolism.