Molecular typing of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis: comparison of results obtained in a multilaboratory effort using identical protocols and MRSA strains

Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.

Absorption of water by room-temperature ionic liquids: effect of anions on concentration and state of water

Near-infrared (NIR) spectrometry was successfully used for the non-invasive and in situ determination of concentrations and structure of water absorbed by room-temperature ionic liquids (RTILs). It was found that RTILs based on 1-butyl-3-methylimidazolium, namely, [BuMIm]+ [BF4]-, [BuMIm]+ [bis((trifluoromethyl)sulfonyl)amide, or Tf2N]- and [BuMIm]+ [PF6]-, are hydroscopic and can quickly absorb water when they are exposed to air. Absorbed water interacts with the anions of the RTILs, and these interactions lead to changes in the structure of water. Among the RTILs studied, [BF4]- provides the strongest interactions and [PF6]- the weakest. In 24 hours, [Bu-MIm]+ [BF4]- can absorb up to 0.320 M of water, whereas [Bu-MIm]+ [PF6]- can only absorb 8.3 x 10(-2) M of water. It seems that higher amounts of water can be absorbed when the anion of the RTIL can strongly interact and hence stabilize absorbed water molecules by forming hydrogen bonds with them or inducing hydrogen bonds among water molecules. More importantly, the NIR technique can be sensitively used for the noninvasive, in situ determination of absorbed water in RTILs, without any pretreatment, and at limits of detection as low as 3.20 x 10(-3) M.

Carriage of respiratory tract pathogens and molecular epidemiology of Streptococcus pneumoniae colonization in healthy children attending day care centers in Lisbon, Portugal

In an effort to establish the rate of carriage of antibiotic resistant respiratory pathogens in children attending urban day care centers (DCC) in Portugal, seven DCC in Lisbon were selected for determining the rate of nasopharyngeal colonization of children between the ages of 6 months to 6 years by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Of the 586 children studied between January and March 1996, 47% carried S. pneumoniae, 72% H. influenzae, and 54% M. catarrhalis. Twenty-four percent of the pneumococci had reduced susceptibility to penicillin, and most of these belonged to serogroups 19, 23, 14, and 6. An additional 19% were fully susceptible to penicillin but showed decreased susceptibility to other antimicrobials. These isolates expressed serogroups 6, 11, 14, 18, 19, and 34. The majority (96%) of M. catarrhalis and 20% of H. influenzae were penicillin resistant due to the production of beta-lactamases. Recent antimicrobial use was associated with carriage of penicillin non-susceptible pneumococci and beta-lactamase producing H. influenzae (p < 0.05). Individual DCC differed substantially from one another in their rates of carriage of antibiotic resistant H. influenzae and S. pneumoniae. Characterization of antibiotic resistant S. pneumoniae isolates by molecular fingerprinting techniques showed that each DCC had a unique microbiological profile, suggesting little, if any, exchange of the resistant microbial flora among them. An exception to this was the presence of isolates belonging to two internationally spread epidemic clones: the multiresistant Spanish/USA clone expressing serotype 23F, and the penicillin and sulfamethoxazole-trimethoprim resistant French/Spanish clone (serotype 14) which were detected in four and three DCC, respectively.

Chiral Ionic Liquid that Functions as Both Solvent and Chiral Selector for the Determination of Enantiomeric Compositions of Pharmaceutical Products

We have successfully synthesized both enantiomers of a novel chiral ionic liquid, (R)- and (S)-[(3-chloro-2-hydroxypropyl) trimethylammonium][bis((trifluoromethyl)sulfonyl)amide] ((R)- and (S)-[CHTA]+[Tf2N]-) in optically pure form by a simple ion exchange reaction from corresponding chloride salts that are commercially available. In addition to the ease of preparation, this chiral IL has relatively high thermal stability (up to 300 degrees C), is liquid at room temperature (glass transition temperature of -58.4 degrees C), and exhibits strong enantiomeric recognition. The high solubility power and strong enantiomeric recognition ability make it possible to use this chiral IL to solubilize an analyte and to induce diastereomeric interactions for the determination of enantiomeric purity. In fact, we have successfully developed a novel method based on the near-infrared technique with this chiral IL serving both as solvent and as a chiral selector for the determination of enantiomeric purity. Enantiomeric compositions of a variety of pharmaceutical products and amino acids with different shape, size, and functional groups can be sensitively (milligram concentration) and accurately (enantiomeric excess as low as 0.6%) determined by use of this method.

Fluorescence determination of enantiomeric composition of pharmaceuticals via use of ionic liquid that serves as both solvent and chiral selector

A new method has been developed for the sensitive and accurate determination of enantiomeric compositions of a variety of drugs, including propranolol, naproxen, and warfarin. The method is based on the use of the fluorescence technique to measure diastereomeric interactions between both enantiomeric forms of a drug with an optically active room temperature ionic liquid (RTIL) followed by partial least squares analysis of the data. The chiral RTIL used in this study, S-[(3-chloro-2-hydroxypropyl) trimethylammonium] [bis((trifluoromethyl)sulfonyl)amide] (S-[CHTA](+) [Tf(2)N](-)), is a novel chiral RTIL that has been synthesized successfully recently in our laboratory in optically pure form using a simple one-step reaction with commercially available reagents. The high solubility power and strong enantiomeric recognition ability make it possible to use this chiral RTIL to solubilize a drug and to induce diastereomeric interactions for the determination of enantiomeric purity, that is, to use it as both solvent and chiral selector. Enantiomeric compositions of a variety of pharmaceutical products with different shapes, sizes, and functional groups can be determined sensitively (microgram concentration) and accurately (enantiomeric excess as low as 0.30% and enantiomeric impurity as low as 0.08%) by use of this method.

Impact of adherence to antiretroviral therapy in HIV-1-infected patients at a university public service in Brazil

The objective of this study was to assess if a simple evaluation, adherence to antiretroviral therapy, would correlate to clinical and laboratory outcomes. We followed an open cohort of patients from a public teaching hospital AIDS outpatient clinic. Patients were categorized according to adherence as: regular (Reg), optimal, all doses all days, tolerating only irregular timing (+/- 2 hours) of intake; quasi-regular (qReg), those missing up to four doses or 1 full day during a month; irregular (Irreg), all other irregular regimens, and ignored (Ign), those without information. The results from a simple questionnaire were compared to CD4+ cell counts and human immunodeficiency virus type 1 (HIV-1) RNA plasma viremia. One hundred eighty-two HIV-1-infected patients (126 males, 69%; 56 females, 31%) were analyzed. Information on adherence was available for 168 (90%). Reg adherence was reported by 75 (41%) patients, qReg adherence by 35 (19%), and Irreg by 53 (29%) of patients. The main reasons for nonadherence were forgetfulness, intolerance, use of alcohol, and misunderstanding of prescription. A significant increase of CD4+ T-cell counts and absolute gain were only observed among Reg and qReg users (p < 0.001). The median viral RNA load log10 decreases were -1.68, -1.45, -0.9 log, respectively, for Reg, qReg, and Irreg patients (p = 0.043, Kruskal-Wallis). Development of and death from AIDS occurred almost exclusively among those with Ign or Irreg adherence. Previous use of antiretroviral therapy may have had an impact in treatment response. Individuals who were treatment-naive were more likely to be Reg users (41%). Although more refined methods to assess adherence should be implemented when available, the inability to do so should not prevent simple, albeit subjective measurements that also correlate with favorable outcome. Mechanisms to improve adherence should be considered an integral part of antiretroviral therapy.

Clonal distribution of methicillin-resistant Staphylococcus aureus in Poland

We report on a study of 158 methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates obtained from 1990 to 1996 in 18 different hospitals in Poland. All isolates were recovered from infection and carriage sites of patients, carriage sites of health care personnel, and hospital environment samples. Fifty-seven MRSA strains described here were studied previously and these were divided into two different clusters according to the degree of heterogeneity of methicillin resistance expression. The aim of this study was to extend the correlation between the two clusters and identify the clonal identities among all isolates by a combination of different methodologies: (i) analysis of mecA polymorphs and Tn554 insertion patterns and (ii) determination of pulsed-field gel electrophoresis patterns of chromosomal SmaI digests. Ninety-seven of 158 strains showed a heterogeneous expression of resistance to methicillin. Among these, 75 (77.3%) were ClaI-mecA type I, ClaI-Tn554 type NH (NH, no homology with transposon Tn554), and pulsed-field gel electrophoresis (PFGE) pattern A (I::NH::A); 10 isolates were III::B::M (10.3%); and the remaining clones included a few or single isolates. The isolates with homogeneous expression of resistance to methicillin (n = 61) were predominantly ClaI-mecA type III (49 of 61 [80.3%]) but had great variability in their ClaI-Tn554 and PFGE patterns. This study confirmed the existence of two main clusters of MRSA in Poland.

Generation and characterization of a recombinant chimeric protein (rCpLi) consisting of B-cell epitopes of a dermonecrotic protein from Loxosceles intermedia spider venom

A chimeric protein was constructed expressing three epitopes of LiD1, a dermonecrotic toxin from the venom of Loxosceles intermedia spider. This species is responsible for a large number of accidents involving spiders in Brazil. We demonstrated that the chimeric protein (rCpLi) generated is atoxic and that antibodies previously developed in rabbits against synthetic epitopes reactive with rCpLi in ELISA and immunoblot assays. The antibody response in rabbits against the rCpLi was evaluated by ELISA and we have detected an antibody response in all immunized animals. Overlapping peptides covering the amino acid sequence of the rCpLi were synthesized on a cellulose membrane, and their recognition by rabbit anti-rCpLi serum assessed. Three different antigenic regions were identified. The percentage of inhibition of the dermonecrotic, hemorrhagic and edematogenic activities caused by the recombinant protein LiD1r in naïve rabbits was assessed by pre-incubation with anti-rCpLi antibodies. Anti-rCpLi induced good dermonecrotic and hemorrhagic protection. The levels of protection were similar to the antiboides anti-LiD1r. In summary, we have developed a polyepitope recombinant chimeric protein capable of inducing multiple responses of neutralizing antibodies in a rabbit model. This engineered protein may be a promising candidate for therapeutic serum development or vaccination.

Continuous lipase-catalyzed production of fatty acid ethyl esters from soybean oil in compressed fluids

This work investigates the continuous production of fatty acid ethyl esters from soybean oil in compressed fluids, namely carbon dioxide, propane and n-butane, using immobilized Novozym 435 as catalyst. The experiments were performed in a packed-bed bioreactor evaluating the effects of temperature in the range of 30-70 degrees C, from 50 to 150 bar, oil to ethanol molar ratio of 1:6-1:18 and solvent to substrates mass ratio of 4:1-10:1. In contrast to the use of carbon dioxide and n-butane, results showed that lipase-catalyzed alcoholysis in a continuous tubular reactor in compressed propane might be a potential route to biodiesel production as high reaction conversions were achieved at mild temperature (70 degrees C) and pressure (60 bar) conditions in short reaction times.

Synthesis of eugenol esters by lipase-catalyzed reaction in solvent-free system

Enzymatic esterification of eugenol is a matter of great scientific and technological interest due to the well-known drawbacks of the chemical-catalyzed route as well as the potential use of produced compounds as natural antimicrobials. This work reports the maximization of eugenil acetate production by esterification of eugenol and acetic anhydride in a solvent-free system using Novozym 435 as catalyst. The antimicrobial activity of eugenol and eugenil acetate was also determined. The operating conditions that maximized eugenil acetate production were 50 °C, eugenol to acetic anhydride of 1:3, 150 rpm, and 5.5 wt% of enzyme, with a conversion of 99 %. A kinetic study was performed to assess the influence of substrates molar ratio, enzyme concentration, and temperature on eugenil acetate yield. Results show that an excess of anhydride, low enzyme concentration (1 wt%), and 60 °C afforded nearly complete conversion after 6 h of reaction. The highest antimicrobial activity of eugenil acetate was observed against Acinetobacter sp. (48.66 mm) at concentration of 20 μL. Results indicate that the esterification of eugenol improved its antimicrobial properties. New experimental data on enzymatic esterification of eugenol and acetic anhydride are reported in this work, showing a promising perspective to overcome the inconvenient of the chemical-catalyzed route for obtaining antimicrobial natural compounds.

Determination of enantiomeric compositions of pharmaceutical products by near-infrared spectrometry

A new method for the determination of enantiomeric compositions of a variety of drugs including propranolol, atenolol, and ibuprofen has been developed. The method is based on the use of the near-infrared technique to measure diastereomeric interactions between an added carbohydrate compound and both enantiomeric forms of a drug followed by evaluation of the data by partial least square analysis. The fact that the method works well with all three macrocyclic carbohydrates with different cavity sizes (i.e., alpha-, beta-, and gamma-cyclodextrin) and with sucrose, which is a linear carbohydrate, clearly demonstrates that it is not necessary to have inclusion complex formation to produce effective diastereomeric interactions. Rather a simple adsorption of the drug onto a carbohydrate is sufficient. Since inclusion complex formation is not a requisite, this method is not limited to the three drugs evaluated in this study but is rather universal as it can, in principle, be used for the sensitive and accurate determination of enantiomeric compositions of many different types of drugs with only about 1.5mg/mL concentration and enantiomeric excess as low as 0.80%, in water or in a mixture of water with organic solvent. Furthermore, it does not rely on the use of rather expensive carbohydrates such as cyclodextrins but is equally as effective even with a simple and inexpensive carbohydrate such as sucrose.

Determination of Enantiomeric Compositions of Amino Acids by Near-Infrared Spectrometry through Complexation with Carbohydrate

A new method has been developed for the determination of enantiomeric compositions of a variety of compounds. The method is based on the use of the near-infrared technique to measure diastereomeric interactions between an added carbohydrate compound with both enantiomeric forms of an analyte followed by partial least-squares analysis of the data. The fact that the method works well with all three macrocyclic carbohydrates with different cavity size (i.e., alpha-, beta-, and gamma-cyclodextrin) as well as with sucrose, which is a linear carbohydrate, clearly demonstrates that it is not necessary to have inclusion complex formation in order to produce effective diastereomeric interactions. Rather, a simple adsorption of the analyte onto a carbohydrate is sufficient. Since inclusion complex formation is not a requisite, this method is not limited to the amino acid studies here but is rather universal and sensitive as it can, in principle, be used to determine enantiomeric compositions for all types of compounds with only microgram concentration and enantiomeric excess as low as 1.5%, in water or in a mixture of water and organic solvent. Furthermore, it does not rely on the use of rather expensive carbohydrates such as cyclodextrins but is equally as effective even with a simple and inexpensive carbohydrate such as sucrose.

Prevention, removal and inactivation of Escherichia coli and Staphylococcus aureus biofilms using selected monoterpenes of essential oils

AIMS

The aim of this study was to investigate the antibiofilm potential of five essential oil (EO) components with cyclic (sabinene-SAB, carveol-C1, carvone-C2) and acyclic (citronellol-C3 and citronellal-C4) structures against Escherichia coli and Staphylococcus aureus.

METHODS AND RESULTS

The selected EO components prevented biofilm set-up, with C3 and C4 causing remarkable effects. When applied against pre-established biofilms, they promoted high biomass removal and inactivation of biofilm cells. Moreover, no viable E. coli biofilm cells were detected after exposure to SAB at 5 × MIC and 10 × MIC, and a significant viability decrease was observed for both bacteria with the other EO components. SAB, C3 and C4 caused the most prominent effects apparently due to their octanol-water partition coefficient (Po/w), the number of rotatable bonds (n-ROTB) and the free hydroxyl groups.

CONCLUSIONS

The overall results demonstrated that the selected EO components, particularly SAB, C3 and C4 are of interest as new lead molecules to both prevent biofilm set-up and to control pre-established biofilms of E. coli and S. aureus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The tested EO components exhibited prominent antibiofilm properties against E. coli and S. aureus providing a novel and effective alternative/complementary approach to counteract chronic infections and the transmission of diseases in clinical settings.

Columbus navigated TKA system: clinical and radiological results at a minimum of 5 years with survivorship analysis

The major factors that determine a favorable long-term clinical and functional outcome after conventional total knee arthroplasty (TKA) include correct implant positioning and restoration of the mechanical axis with soft tissue balancing to reduce aseptic failure; hence, the need for further developmental strategies that improve the accuracy and reproducibility of the surgical technique remains paramount for contemporary navigation research. Not all navigation systems are the same. The literature published thus far on mid-term results of navigated TKA relies on software that has no step-by-step soft tissue balancing with the tibia-first technique. The results are equivalent to those of conventional TKA.Therefore, the current authors conducted a minimum 5-year follow-up of a soft tissue-based navigated TKA system with the goal of soft tissue balancing. They analyzed intraoperative alignment and range of motion measurements, functional outcomes, radiographic assessment, and survival rates of high-flexion, high-conformity unresurfaced patella TKAs. The results at 5 years revealed a component revision rate of 0% compared with other nonnavigated TKAs (2.8% revision rate). The authors achieved a well-balanced TKA with a 0°±2° mechanical axis and an improved range of motion from 95° preoperatively to 110° postoperatively.

The Ca2+-dependent protease Calpain A regulates Cactus/I kappaB levels during Drosophila development in response to maternal Dpp signals

Regulation of NF kappaB activity is central to many processes during development and disease. Activation of NF kappaB family members depends on degradation of inhibitory I kappaB proteins. In Drosophila, a nuclear gradient of the NF kappaB/c-rel protein Dorsal subdivides the embryonic dorsal-ventral axis, defining the extent and location of mesodermal and ectodermal territories. Activation of the Toll pathway directs Dorsal nuclear translocation by inducing proteosomal degradation of the I kappaB homologue Cactus. Another mechanism that impacts on Dorsal activation involves the Toll-independent pathway, which regulates constitutive Cactus degradation. We have shown that the BMP protein Decapentaplegic (Dpp) inhibits Cactus degradation independent of Toll. Here we report on a novel element of this pathway: the calcium-dependent protease Calpain A. Calpain A knockdowns increase Cactus levels, shifting the Dorsal gradient and dorsal-ventral patterning. As shown for mammalian I kappaB, this effect requires PEST sequences in the Cactus C-terminus, implying a conserved role for calpains. Alteration of Calpain A or dpp results in similar effects on Dorsal target genes. Epistatic analysis confirms Calpain A activity is regulated by Dpp, indicating that Dpp signals increase Cactus levels through Calpain A inhibition, thereby interfering with Dorsal activation. This mechanism may allow coordination of Toll, BMP and Ca(2+) signals, conferring precision to Dorsal-target expression domains.

Non-surgical treatment of peri-implant pathology

INTRODUCTION

Peri-implant pathologies consist of an inflammatory process affecting the soft and hard tissues surrounding the implants. Chlorhexidine is considered the gold standard antiseptic, with a large variety of choice in administration. In this study, a protocol for the irrigation of peri-implant pockets with a chlorhexidine gel, using a plastic needle for the delivery of the product into the peri-implant pockets is described.

STUDY PARTICIPANTS AND METHODS

Nine patients with at least one implant presenting peri-implant pathology (inflamed soft tissue associated with bone loss around the implant) were enrolled in this prospective clinical study, and followed-up for 1 year, where clinical parameters such as modified plaque index, modified bleeding index, probing pocket depths, attachment levels were assessed at baseline, 1 month, and 1 year after implementation of the treatment protocol.

RESULTS

Treatment success was achieved in eight of the nine patients (and in 11 of the 13 implants) according to the success criteria adopted by the authors of this study.

DISCUSSION

Infection control lies at the heart of peri-implant treatment. The control of three factors such as optimal diagnosis, removal of the aetiological factor of the disease (proper removal of debris and decontamination of the peri-implant sulcus/pocket) and a good patient's oral hygiene self-care represents the key to success, resulting in good treatment outcomes when managing peri-implant pathologies. The protocol used (irrigation of peri-implant pockets with chlorhexidine gel delivered by a plastic needle) is considered to be of utility.

Learning from others: an invasive lizard uses social information from both conspecifics and heterospecifics

Species that are able to solve novel problems through social learning from either a conspecific or a heterospecific may gain a significant advantage in new environments. We tested the ability of a highly successful invasive species, the Italian wall lizard Podarcis sicula, to solve a novel foraging task when social information was available from both a conspecific and an unfamiliar heterospecific (Podarcis bocagei). We found that Italian wall lizards that had access to social information made fewer errors, regardless of whether the demonstrator was a conspecific or a heterospecific, compared to Italian wall lizards that individually learnt the same task. We suggest that social learning could be a previously underappreciated, advantageous mechanism facilitating invasions.

A review of thermal methods and technologies for diabetic foot assessment

Temperature analysis has been considered as a complementary method in medical evaluation and diagnosis. Several studies demonstrated that monitoring the temperature variations of the feet of diabetic patients can be helpful in the early identification of diabetic foot manifestations, and also in changing behaviors, which may contribute to reducing its incidence. In this review, several and most used techniques for assessing the temperature of the feet are presented, along with original published work on specific applications in diabetic foot complications. A review of solutions and equipment that operate according to the temperature assessment techniques is also presented. Finally, a comparison between the various technologies is presented, and the authors share their perspective on what will be the state of affairs in 5 years.

Immediate effects of adding mental practice to physical practice on the gait of individuals with Parkinson's disease: Randomized clinical trial

BACKGROUND

Mental practice has shown benefits in the rehabilitation of neurological patients, however, there is no evidence of immediate effects on gait of individuals with Parkinson's disease.

OBJECTIVE

Determine the effects of mental practice activity added to physical practice on the gait of individuals with Idiopathic Parkinson's Disease (IPD).

METHODS

20 patients classified with stage 2 and 3, according to the Hoehn and Yahr scale were randomized into 2 groups. The experimental group (N = 10) was submitted to a single session of mental practice and physical practice gait protocol and the control group (N = 10) only to physical practice. The primary outcomes were stride length and total stance and swing time. Secondary outcomes were hip range of motion, velocity and mobility. Subjects were reassessed 10 minutes, 1 day and 7 days after the end of the session.

RESULTS

There was no statistically significant difference between the groups. An intragroup difference was observed in velocity, stride length, hip range of motion, and mobility, as well as total stance and swing time. These results were also observed on follow-ups.

CONCLUSIONS

Mental practice did not have a greater effect on the gait of individuals with IPD than physical practice, after a single session.

Continuous lipase-catalyzed esterification of soybean fatty acids under ultrasound irradiation

This work investigates the continuous production of alkyl esters from soybean fatty acid (FA) charges using immobilized Novozym 435 as catalyst. The experiments were performed in a packed-bed bioreactor evaluating the effects of FA charge to alcohol (methanol and ethanol) molar ratio, from 1:1 to 1:6, substrate flow rate in the range of 0.5-2.5 mL/min and output irradiation power up to 154 W, at fixed temperature of 65 °C, on the reaction conversion. Results showed that almost complete conversions to fatty acids ethyl esters were achieved at mild ultrasonic power (61.6 W), FA to ethanol molar ratio of 1:6, operating temperature (65 °C) and remained nearly constant for long-term reactions without negligible enzyme activity losses.

Energy requirements in early life are similar for male and female goat kids

Little is known about the gender differences in energetic requirements of goats in early life. In this study, we determined the energy requirements for maintenance and gain in intact male, castrated male and female Saanen goat kids using the comparative slaughter technique and provide new data on their body composition and energy efficiency. To determine the energy requirements for maintenance, we studied 21 intact males, 15 castrated males and 18 females (5.0±0.1 kg initial body weight (BW) and 23±5 d of age) using a split-plot design with the following main factors: three genders (intact males, castrated males, and females) and three dry matter intake levels (ad libitum, 75% and 50% of ad libitum intake). A slaughter group included three kids, one for each nutritional plane, of each gender, and all three animals within a group were slaughtered when the ad libitum kid reached 15 kg in BW. Net energy requirements for gain were obtained for 17 intact males, eight castrated males and 15 females (5.1±0.4 kg BW and 23±13 d of age). Animals were fed ad libitum and slaughtered when they reached 5, 10, and 15 kg in BW. A digestion trial was performed with nine kids of each gender to determine digestible energy, metabolizable energy and energy metabolizability of the diet. Our results show no effect of gender on the energy requirements for maintenance and gain, and overall net energy for maintenance was 205.6 kJ/kg^0.75 empty body weight gain (EBW) (170.3 kJ/kg^0.75 BW) from 5 to 15 kg BW. Metabolizable energy for maintenance was calculated by iteration, assuming heat production equal to metabolizable energy intake at maintenance, and the result was 294.34 kJ/kg^0.75 EBW and k_m of 0.70. As BW increased from 5 to 15 kg for all genders, the net energy required for gain increased from 9.5 to 12.0 kJ/g EBW gain (EWG), and assuming k_g = 0.47, metabolizable energy for gain ranged from 20.2 to 25.5 kJ/g EWG. Our results indicate that it is not necessary to formulate diets with different energetic content for intact male, castrated male and female Saanen goat kids weighing from 5 to 15 kg.

The mGluR stimulating GFAP phosphorylation in immature hippocampal slices has some properties of a group II receptor

In a previous study we showed that phosphorylation of the astrocytic marker glial fibrillary acidic protein (GFAP) in hippocampal slices from immature rats (P12-P16) is regulated by a metabotropic glutamate receptor (mGluR). The subtypes of these receptors are divided into three groups and exhibit two distinct transduction signals: activation of phospholipase C and liberation of internal calcium (group I) or modulation of cAMP synthesis (groups II and III). Here we investigated the subtype of mGluR involved. Phosphorylation was strongly stimulated by the selective group II agonists DCG IV, L-CCG-I and 1S,3S-ACPD, whereas the group I agonist 3,5-DHPG and the group III agonist L-AP4 had no effect. These results show that the receptor regulating GFAP phosphorylation in the immature hippocampus has some of the properties of a group II mGluR.

Predator (cat hair)-induced enhancement of hippocampal long-term potentiation in rats: involvement of acetylcholine

Extensive literature has demonstrated that arousal and fear modify memory acquisition and consolidation. Predator hair and odors increase arousal in rats and, therefore, may influence information encoding and synaptic plasticity in the rodent nervous system. In behavioral experiments, we confirm that laboratory-bred Long Evans rats avoid cat hair. Electrophysiological work in vivo showed that long-term potentiation (LTP) in the dentate gyrus induced by perforant path stimulation was enhanced for 5-7 days when LTP induction occurred in the presence of cat hair relative to fake hair. The muscarinic receptor antagonist scopolamine (i.p.) reversed the cat hair-elicited LTP enhancement without affecting weaker LTP elicited in the presence of fake hair. Thus, exposure to a predator stimulus elicits a cholinergically-dependent state of heightened plasticity that may serve to facilitate information storage in hippocampal circuits.