Hybrid microwave oscillators with a virtual cathode

A review is given of the developments and theoretical investigations of a fundamentally new class of microwave devices, namely, hybrid microwave oscillators with a virtual cathode, which combine the useful properties of virtual cathodes with the advantages of those traditional microwave oscillators that operate with subcritical-current beams and have a high efficiency in generating ultrarelativistic electron beams. Among such devices are the following: a hybrid diffractional microwave oscillator with a virtual cathode, a hybrid gyrodevice with a virtual cathode, a hybrid beam-plasma vircator, a hybrid gyrocon with a virtual cathode, a hybrid Cherenkov oscillator with a virtual cathode, a hybrid microwave oscillator of the “vircator + traveling-wave tube” type, an original two-beam tube with a virtual cathode, and a klystron-like vircator.     

Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare.     

The lyotropic liquid crystal properties of n-octyl 1-O-beta-D-glucopyranoside and related n-alkyl pyranosides

X-ray diffraction patterns have been obtained for the lyotropic phases of n-octyl 1-O-beta-D-glucopyranoside and the related n-heptyl, n-nonyl and n-decyl compounds with water. The octyl compound exhibits all three liquid crystal phases and forms a micellar solution with increasing solvation, when the crystal come into contact with water at room temperature. The X-ray diffraction patterns show a one-dimensional lamellar phase with [dx] = 28.4 A, a three-dimensional face-centered cubic phase with [a] = 51.2 A, and a two-dimensional hexagonal phase with [a] = [b] = 36.7 A. The micellar solution has a distribution pattern with a maximum at [dx] = 33.8 A. Crystals of the heptyl, nonyl and decyl derivatives form only the lamellar phases and the micellar solution on contact with water at room temperature.     

Influence of prior and visual information on eye movements in amblyopic children

This study analyzed the characteristics of pursuit and assessed the influence of prior and visual information on eye velocity and saccades in amblyopic and control children, in comparison to adults. Eye movements of 41 children (21 amblyopes and 20 controls) were compared to eye movements of 55 adults (18 amblyopes and 37 controls). Participants were asked to pursue a target moving at a constant velocity. The target was either a ‘standard’ target, with a uniform color intensity, or a ‘noisy’ target, with blurry edges, to mimic the blurriness of an amblyopic eye. Analysis of pursuit patterns showed that the onset was delayed, and the gain was decreased in control children with a noisy target in comparison to amblyopic or control children with a standard target. Furthermore, a significant effect of prior and visual information on pursuit velocity and saccades was found across all participants. Moreover, the modulation of the effect of visual information on the pursuit velocity by group, that is amblyopes or controls with a standard target, and controls with a noisy target, was more limited in children. In other words, the effect of visual information was higher in control adults with a standard target compared to control children with the same target. However, in the case of a blurry target, either in control participants with a noisy target or in amblyopic participants with a standard target, the effect of visual information was larger in children.

     

Measles immunisation in children with allergy to egg.

OBJECTIVE--To examine the occurrence of adverse reactions to measles vaccine given as a single dose to children with egg allergy, and to determine if the administration of single dose to children with a positive result in an intradermal skin prick test with the vaccine is associated with adverse reactions. DESIGN--Review of results of immunisation and prospective study of 96 consecutively presenting children given intradermal skin testing with the vaccine. SETTING--Children''s allergy centre. SUBJECTS--410 children sensitive to egg referred to the allergy unit for advice about measles immunisation. MAIN OUTCOME MEASURES--Nature and severity of reactions associated with the administration of measles vaccine. RESULTS--All children had a positive result in a skin prick test with egg white, and five had a positive result in a skin prick test with vaccine. Of 96 consecutive children, 46 had a positive result in an intradermal test with vaccine. After immunisation with a full dose (0.5 ml) of vaccine adverse reactions were associated with a mild reaction in four children, none of whom required treatment. Only one of the 46 children with a positive result in an intradermal vaccine skin test had a reaction associated with vaccine administration. None of the children with a positive result in a skin prick test with measles vaccine reacted to the vaccine. The rate of minor reactions to the vaccine not requiring treatment was 0.98% (95% confidence interval 0.27% to 2.48%) and serious reactions requiring treatment was 0% (0% to 0.9%). CONCLUSION--Children with IgE mediated allergic reactions to egg protein should be investigated and managed by practitioners with special knowledge in this subject. Measles immunisation should be performed in a setting where any adverse reactions can be dealt with appropriately. Skin tests and measles vaccine and desensitisation are not necessary.     

Inhibition of D-3-aminoisobutyrate-pyruvate aminotransferase by 5-fluorouracil and alpha-fluoro-beta-alanine.

Among pyrimidine derivatives, we found that 5-fluorouracil potently inhibited purified rat liver D-3-aminoisobutyrate-pyruvate aminotransferase, whereas 5-fluorouridine did so to a much lesser extent. 5-Fluorouracil acted as a competitive inhibitor against beta-alanine with a Ki of 56 microM, and was uncompetitive against pyruvic acid, with a Ki of 73 microM. alpha-Fluoro-beta-alanine, a metabolite of 5-fluorouracil, was also a competitive inhibitor with respect to beta-alanine with a Ki of 8.0 mM. 5-Fluorouracil acted also as a competitive inhibitor of 4-aminobutyrate aminotransferase with respect to beta-alanine with a Ki value of 1.9 mM, and was uncompetitive against 2-oxoglutaric acid, with a Ki of 1.8 mM.     

An integrated, stacked microlaboratory for biological agent detection with DNA and immunoassays

An integrated, stacked microlaboratory for performing automated electric-field-driven immunoassays and DNA hybridization assays was developed. The stacked microlaboratory was fabricated by orderly laminating several different functional layers (all 76 x 76 mm(2)) including a patterned polyimide layer with a flip-chip bonded CMOS chip, a pressure sensitive acrylic adhesive (PSA) layer with a fluidic cutout, an optically transparent polymethyl methacrylate (PMMA) film, a PSA layer with a via, a patterned polyimide layer with a flip-chip bonded silicon chip, a PSA layer with a fluidic cutout, and a glass cover plate layer. Versatility of the stacked microlaboratory was demonstrated by various automated assays. Escherichia coli bacteria and Alexa-labeled protein toxin staphylococcal enterotoxin B (SEB) were detected by electric-field-driven immunoassays on a single chip with a specific-to-nonspecific signal ratios of 4.2:1 and 3.0:1, respectively. Furthermore, by integrating the microlaboratory with a module for strand displacement amplification (SDA), the identification of the Shiga-like toxin gene (SLT1) from E. coli was accomplished within 2.5 h starting from a dielectrophoretic concentration of intact E. coli bacteria and finishing with an electric-field-driven DNA hybridization assay, detected by fluorescently labeled DNA reporter probes. The integrated microlaboratory can be potentially used in a wide range of applications including detection of bacteria and biowarfare agents, and genetic identification.     

Twin pregnancy with complete hydatidiform mole and coexisting fetus following ovulation induction with a non-prescribed clomiphene citrate regimen: a case report

Introduction

Until now, studies on paracetamol given intravenously have mainly been performed with the pro-drug propacetamol or with paracetamol in preterm babies above 32 weeks of gestation. Studies in these babies indicate that intravenous paracetamol is tolerated well, however studies on the efficacy of intravenous paracetamol are lacking. There are no pharmacokinetic data on the administration of multiple doses of paracetamol in preterm babies with a gestational age below 32 weeks.

Case presentation

We present a case series of nine Caucasian preterm babies, six boys and three girls, with a mean gestational age of 28.6 weeks (range 25.9 to 31.6 weeks). Case one, a girl with a gestational age of 25 weeks and six days, presented with necrotizing enterocolitis. In the second case, a female baby with a gestational age of 26 weeks and two days presented with hematoma. In case three, a female baby with a gestation of 26 weeks and one day developed intraventricular hemorrhage. In case four, a male baby with a gestational age of 31 weeks and four days presented with pain after vacuum delivery. Case five, a female baby born after a gestation of 29 weeks and six days presented with hematoma. In case six, a male baby with a gestation of 30 weeks and six days presented with hematoma. In case seven, a male baby, born with a gestational age of 30 weeks and six days, presented with caput succedaneum and hematoma. In case eight, a male baby, born after a gestation of 28 weeks and four days, developed abdominal distention. Case nine, a female baby, born with a gestational age of 27 weeks and three days presented with hematoma. These babies were treated with intravenous paracetamol 15 mg/kg every six hours. Serum concentrations and aspartate transaminase were determined after prolonged administration. Pain scores were assessed using the Premature Infant Pain Profile.

Conclusion

Paracetamol serum concentrations ranged from 8 to 64 mg/L after eight to 12 doses of intravenous paracetamol. Adequate analgesia was obtained in seven babies. During paracetamol therapy the median serum level of aspartate transaminase was 20 U/L (range 12 to 186 U/L). This case series indicates that prolonged intravenous administration of paracetamol in preterm babies with a gestational age of less than 32 weeks is tolerated well in the first days after birth. However, in the absence of proper pharmacokinetic data in this age group we cannot advocate the use of paracetamol intravenously.     

Filter combinations and light sources for fluorescence microscopy of quinacrine mustard or quinacrine stained chromosomes

Summary The efficiency of various combinations of primary and secondary filters, and light sources for the fluorescence microscopy of chromosomes stained with quinacrine mustard or quinacrine has been studied quantitatively. Using epi-illumination, strong fluorescence could be obtained with a mercury or xenon lamp in combination with two KP 490 short-wave pass interference filters (tilted to an angle of 60° with the excitation beam) as primary filter, and a K 490 as a secondary filter. The combination of a mercury lamp and a narrow band interference filter with a maximal transmission at about 436 nm as a primary filter together with a K 490 secondary filter results in a good visual image contrast, sufficiently strong fluorescence, and a relatively slow rate of fading.     

New data on aberrant spermatozoa in the ejaculate of Sus domesticus

This paper describes 16 new types of aberrant spermatozoa observed by scanning electron microscopy in the ejaculate of two healthy, sexually mature Landrace boars. The new anomalies observed were 1) spermatozoa with folded tail and abnormal head; 2) tailless spermatozoa with an abnormal connecting piece; 3) immature spermatozoa with two tails of the same length, fused and coiled; 4) spermatozoa with two tails of the same length, fused and coiled, and a small, rounded head; 5) spermatozoa with two fused tails and a wide head; 6) spermatozoa with three tails of the same length, fused and coiled; 7) immature spermatozoa with two heads and two fused tails; 8) spermatozoa with two heads, one at each tip of the tail; 9) spermatozoa with a short, folded tail and a triangular head; 10) spermatozoa with a short tail lacking the intermediate piece; 11) spermatozoa with a short tail, without the main piece and with a long intermediate piece; 12) spermatozoa with a short tail, without the main piece and with a rough head; 13) spermatozoa with small, rounded head; 14) spermatozoa with small, aberrant heads; 15) spermatozoa with small, bacillary heads; and 16) immature spermatozoa with tapering heads.     

On the evocability of a positive oestrogen feedback action on LH secretion in transsexual men and women.

In transsexual men with homosexual behaviour and intact testicular function, as well as in homosexual men with normal gender identity, following a negative oestrogen feedback effect a delayed positive oestrogen feedback action on LH secretion was evoked. By contrast, in transsexual men with hypo- or asexuality and intact testes or hypergonadotrophic hypo- or agonadism, as well as in heterosexual men with normal gender identity, a negative oestrogen feedback effect was not followed by a positive feedback action on LH release. In transsexual women with homosexual behaviour and oligo- and/or hypomenorrhoea, only a weak or at best moderate positive oestrogen feedback action on LH release was evocable, similarly as in castrated and oestrogen-primed heterosexual men. By contrast, in a transsexual woman with bisexual behaviour and eumenorrhoea, a strong positive oestrogen feedback action on LH secretion was evocable, as well as in heterosexual women with normal gender identity.     

Repetitive mating and female fitness in Dysdercus cardinalis (Hemiptera: Pyrrhocoridae)

Using three mating-treatment groups–pairing with a male for life, pairing with a male from adult emergence to first oviposition, and no pairing (virgin)–of Dysdercus cardinalis females in a laboratory study, the following results were obtained. Most of the virgin females did not lay eggs; those that did oviposited for the first time at a considerably older age than females in the other two groups. In a lifetime, females pairing with a male for life and those pairing with a male up to first oviposition produced essentially the same number of eggs, and this was more than 3.5 times the number of eggs laid by a virgin female. Virgin females produced an average of 1.3 clutches in a lifetime, compared with about 4.5 clutches produced by females in the other two groups. Reproductive span was significantly shorter, and fecundity per day of reproductive span significantly greater, for females pairing with males for life than for those pairing with a male up to first oviposition. Age at death was significantly different amongst females in different mating-treatment groups. Virgin females had the longest life, followed by females pairing with a male up to first oviposition and females pairing with a male for life, in that order. There was a positive correlation between lifetime gross reproduction and age at death for females pairing with a male for life. There was no relationship between these two characters for females pairing with a male up to first oviposition. Both females pairing with a male for life and those pairing with a male to first oviposition exhibited a significant inverse relationship between fecundity per day and age at death. The results obtained indicate that (1) mating is a prerequisite for normal gonadal activity in Dysdercus cardinalis , and (2) repetitive mating increases the rate of reproduction. This would reduce the mean age of parenthood which is inversely related to the intrinsic rate of increase.     

Nonverbal Communication and Human–Dog Interaction

Human–dog interaction relies to a large extent on nonverbal communication, and it is therefore plausible that human sensitivity to nonverbal signals affects interactions between human and dog. Experience with dogs is also likely to influence human–dog interactions, and it has been suggested that it influences human social skills. The present study investigated possible links between human nonverbal sensitivity, experience with dogs, and the quality of human–dog interactions. Two studies are reported. In study 1, 97 veterinary students took a psychometric test assessing human nonverbal sensitivity and answered a questionnaire on their experience with dogs. The data obtained were then used to investigate the relationship between experience with dogs and sensitivity to human nonverbal communication. The results did not indicate that experience with dogs improves human nonverbal sensitivity. In study 2, 16 students with high, and 15 students with low, levels of human nonverbal sensitivity were selected. Each of the 31 students interacted once with an unknown dog in a greeting situation, and these human–dog interactions were videoed. We found that a combined score of dog behaviors relating to insecurity was associated with the students' level of nonverbal sensitivity and experience with dogs: the dog showed more of the insecure behavior when interacting with students with a low level of nonverbal sensitivity and no experience with dogs than it did when interacting with students with a high level of nonverbal sensitivity (irrespective of experience with dogs).     

Somatostatin release in the hippocampus in the kindling model of epilepsy: a microdialysis study

Somatostatin biosynthesis in the hippocampus is activated during and following kindling epileptogenesis. The aim of this study was to investigate whether this phenomenon is associated with enhanced somatostatin release in vivo. Experiments have been run in awake, freely moving rats, implanted with a bipolar electrode in the right amygdala (for kindling stimulation), and with a recording electrode and a microdialysis probe in the left hippocampus. Basal somatostatin-like immunoreactivity (-LI) release was significantly greater in kindled than naive rats. In naive rats, a 2-min perfusion with 100 mM K(+) did not affect behavior and EEG recordings and nonsignificantly increased somatostatin-LI release; a 10-min K(+) perfusion evoked numerous wet dog shakes, electrical seizures (class 0; latency congruent with 8 min, duration congruent with 8 min), and somatostatin-LI release ( congruent with 350% of basal); and a single kindling after-discharge (4 +/- 3-s duration in the hippocampus) also evoked somatostatin-LI release ( congruent with 200% of basal). In kindled rats, a 2-min 100 mM K(+) perfusion evoked hippocampal discharges in three of seven animals (latency congruent with 2 min, mean duration congruent with 1.5 min) and increased somatostatin-LI release ( congruent with 250% of basal); a 10-min K(+) perfusion evoked behavioral seizures (class 1 to 5, latency congruent with 4 min, mean duration congruent with 12 min) with numerous wet dog shakes and robust somatostatin-LI release ( congruent with 350% of basal); and a kindling stimulation evoked generalized seizures (class 4 or 5, 77 +/- 15-s duration in the hippocampus) with remarkable somatostatin-LI release ( congruent with 300% of basal). These data demonstrate that hippocampal somatostatin release is increased in the kindling model in vivo.     

Comparison of the mechanisms of latency shift in pattern reversal visual evoked potential induced by blurring and contrast reduction

Reduction of visual acuity or of the contrast of the stimulus induces a prolongation of the pattern reversal visual evoked potential (PR-VEP) latencies, perhaps because these conditions cause deterioration of the visual capacity to recognize objects and may preferentially activate the slower central retina channel. The PR-VEP was obtained with a video stimulator and 3 kinds of stimuli: total video field, video with a central scotoma and a restricted central stimulus. The subjects were tested under conditions of normal (20/20) and reduced visual acuity (20/200) with 14′ and 56′ checks and 60% contrast, and under conditions of normal visual acuity (20/20) with 14′ checks and with stimulus contrast of 60% and 25%. Blurring increased latencies and decreased amplitudes only with the 14′ checks stimulus but no with 56′ checks, and the amplitudes obtained with the central stimulus became greater than those obtained with a central scotoma. Reducing contrast increased only latency, and there was not difference between amplitudes obtained with a central stimulus or a central scotoma. We conclude that blurring small checks induces a preferential stimulation of receptors in the central retina, but the same effect was not observed when stimulus contrast was reduced.     

Ionization of amino acid residues involved in the catalytic mechanism of aspartate transcarbamoylase.

The chemical and kinetic mechanisms of the reaction catalyzed by the catalytic trimer of aspartate transcarbamoylase have been examined. The variation of the kinetic parameters with pH indicated that at least four ionizing amino acid residues are involved in substrate binding and catalysis. The pH dependence of K(ia) for carbamoyl phosphate and the K(i) for N-(phosphonoacetyl)-L- aspartate revealed that a protonated residue with a pK value of 9.0 is required for the binding of carbamoyl phosphate. However, the variation with pH of K(i) for succinate, a competitive inhibitor of aspartate, and for cysteine sulfinate, a slow substrate, showed that a single residue with a pK value of 7.3 must be protonated for binding these analogues and, by inference, aspartate. The profile of log V against pH displayed a decrease in reaction rate at low and high pH, suggesting that two groups associated with the Michaelis complex, a deprotonated residue with a pK value of 7.2 and a protonated group with a pK value of 9.5, are involved in catalysis. By contrast, the catalytically productive form of the enzyme-carbamoyl phosphate complex, as illustrated in the bell-shaped pH dependence of log (V/K)(asp), is one in which a residue with a pK value of 7.0 must be protonated while a group with a pK value of 9.1 is deprotonated. This interpretation is supported by the results from the temperature dependence of the V and V/K profiles and from the pH dependence of pK(i) for the aspartate analogues.(ABSTRACT TRUNCATED AT 250 WORDS)     

Re-challenge with pemetrexed in advanced mesothelioma: a multi-institutional experience

ABSTRACT: BACKGROUND: Although first-line therapy for patients affected by advanced mesothelioma is well established, there is a lack of data regarding the impact of second-line treatment. METHODS: We retrospectively collected data of patients affected by advanced mesothelioma, already treated with first-line therapy based on pemetrexed and platin, with a response (partial response or stable disease) lasting at least 6 months, and re-treated with a pemetrexed-based therapy at progression. The primary objective was to describe time to progression and overall survival after re-treatment. RESULTS: Overall across several Italian oncological Institutions we found 30 patients affected by advanced mesothelioma, in progression after a 6-month lasting clinical benefit following a first-line treatment with cisplatin and pemetrexed, and re-challenged with a pemetrexed-based therapy. In these patients we found a disease control rate of 66%, with reduction of pain in 43% of patients. Overall time to progression and survival were promising for a second-line setting of patients with advanced mesothelioma, being 5.1 and 13.6 months, respectively. CONCLUSIONS: In our opinion, when a patient experience a long-lasting benefit from previous treatment with pemetrexed combined with a platin compound, the same treatment should be offered at progression.     

Fluorescence resonance energy transfer analysis of subunit stoichiometry of the epithelial Na+ channel

Activity of the epithelial Na(+) channel (ENaC) is rate-limiting for Na(+) (re)absorption across electrically tight epithelia. ENaC is a heteromeric channel comprised of three subunits, alpha, beta, and gamma, with each subunit contributing to the functional channel pore. The subunit stoichiometry of ENaC remains uncertain with electrophysiology and biochemical experiments supporting both a tetramer with a 2alpha:1beta:1gamma stoichiometry and a higher ordered channel with a 3alpha:3beta:3gamma stoichiometry. Here we used an independent biophysical approach based upon fluorescence resonance energy transfer (FRET) between differentially fluorophore-tagged ENaC subunits to determine the subunit composition of mouse ENaC functionally reconstituted in Chinese hamster ovary and COS-7 cells. We found that when all three subunits were co-expressed, ENaC contained at least two of each type of subunit. Findings showing that ENaC subunits interact with similar subunits in immunoprecipitation studies are consistent with these FRET results. Upon native polyacrylamide gel electrophoresis, moreover, oligomerized ENaC runs predominantly as a single species with a molecular mass of >600 kDa. Because single ENaC subunits have a molecular mass of approximately 90 kDa, these results also agree with the FRET results. The current results as a whole, thus, are most consistent with a higher ordered channel possibly with a 3alpha:3beta:3gamma stoichiometry.     

ATP content and maturational/developmental ability of bovine oocytes with various cytoplasmic morphologies

We examined the relationship among morphological appearance (six groups) of bovine oocytes, ATP content and maturational/developmental ability. Oocytes with a brown ooplasm (with or without a dark region) had intermediate levels of ATP at the germinal vesicle (GV) stage and showed higher rates of first polar body (PB) extrusion than the other groups. Oocytes with a low level of ATP (oocytes with a pale ooplasm without dark clusters) and oocytes with a high level of ATP (oocytes with a black ooplasm) showed lower rates of PB extrusion. During in vitro maturation, ATP levels in oocytes decreased at around GV breakdown and increased toward metaphase II (MII). MII oocytes having a brown ooplasm with a dark region, which had good developmental capacity, had a relatively high level of ATP. MII oocytes with a brown or pale ooplasm without dark clusters, which had poor developmental capacity, had low ATP levels. MII oocytes with a black ooplasm, which had poor developmental capacity, had an unusually high level of ATP. These results suggest that the morphological appearance of bovine oocytes is closely related to their ATP levels and that cytoplasmic morphology will give an advantage for the selection of oocytes with a high maturational and developmental ability.