Neurocognitive outcome in children and adolescents following infectious encephalitis

Infectious encephalitis in children is fairly uncommon, but unfavorable outcomes are seen in many survivors. The aim of this study was to prospectively describe the long-term neurocognitive consequences following infectious encephalitis in childhood. Children admitted to a primary and tertiary hospital in Sweden between 2011 and 2016 were asked to participate. Fifty-nine children were assessed at a median time of 18 months (IQR 18-20) after hospitalization. Follow-up included measures of intellectual functioning, attention, working memory, and executive functions. Caregiver ratings of executive functioning and behavioral - emotional symptoms were assessed with standardized questionnaires. Neurocognitive outcome and measures of executive functions and behavioral-emotional symptoms varied greatly among participants. Basic auditory attention, working memory, and mental processing speed were affected and significantly lower compared to a standardized mean. Other domains identified as areas of vulnerability included executive functions, sustained attention, and the exert of self-control. Behavioral-emotional symptoms were less common; however, somatic complaints and behaviors related to conduct problems were seen in about one-third of individuals. This study highlights the importance of a comprehensive neurocognitive examination to identify children with unfavorable outcomes.

Passivation of N-Type Silicon by Hydrogen

Infrared spectroscopy has been used to study hydrogen passivation of P, As, and Sb donors in Si. The spectra show several new absorption bands due to donor-H complexes. By comparing spectra after different heat treatments it is shown directly that the passivation is due to complex formation.

Quality of child-parent attachment moderates the impact of antenatal stress on child fearfulness

BACKGROUND

Animal studies have shown that prenatal stress has persisting effects on several aspects of offspring development; more recent studies show that this effect may be eliminated by positive postnatal rearing. Human studies of prenatal anxiety/stress are now also beginning to document links between antenatal stress/anxiety and behavioural and cognitive development of the child; however, there is no human evidence as to whether the early caregiving environment moderates the effect of antenatal anxiety/stress on child outcomes.

METHODS

Antenatal and postnatal measures of stress were collected on 123 women who were recruited from an antenatal clinic. Laboratory-based assessment of the children's cognitive development and fearfulness were assessed when the children were aged 17 months. In addition, child-parent attachment quality was assessed using the Strange Situation.

RESULTS

Attachment classification moderated the link between antenatal stress and observed fearfulness. The effect of antenatal stress on fearfulness was most accentuated in children with an Insecure/Resistant attachment classification; the significant antenatal stress x attachment classification interaction held after controlling for postnatal stress and obstetric, social and demographic factors. Attachment did not moderate the effects of antenatal anxiety on cognitive development.

DISCUSSION

These findings provide the first human evidence that postnatal parenting may moderate the adverse effects of antenatal stress. These results raise developmental questions about the timing and effect of interventions to reduce the adverse effects of antenatal stress exposure.

Maternal antenatal anxiety and amniotic fluid cortisol and testosterone: possible implications for foetal programming

Both animal and human studies have shown that maternal stress or anxiety during pregnancy is associated with increased risk of disturbance in offspring neurodevelopment and behaviour. In animal models, increased foetal exposure to glucocorticoids has been found to be one mechanism for such foetal programming. Little is understood of the mediating mechanisms in humans, and one aim of our research programme is to investigate this further. This review presents a synopsis of some of our recent results. We aimed to test the hypothesis that maternal anxiety was associated with raised maternal cortisol, and that this in turn was related to increased foetal exposure to cortisol. We studied this by recruiting women at amniocentesis, obtained their Spielberger State Anxiety scores, and assessed maternal plasma cortisol and amniotic fluid cortisol. We also examined maternal plasma and amniotic fluid testosterone levels. Awaiting amniocentesis was in general anxiogenic, but with a wide range of anxiety scores. Maternal anxiety was significantly associated with plasma cortisol before 17 weeks, albeit of modest magnitude (r = 0.0.23), and not after 17 weeks of gestation. This is probably due to the known attenuation of the maternal hypothalamic-pituitary-adrenal axis with increasing gestation. We found a strong correlation between maternal plasma and amniotic fluid cortisol levels, which increased with gestation and became robust after 18 weeks. This correlation increased with maternal anxiety, suggesting a possible effect of maternal mood on placental function. There was a positive correlation between cortisol and testosterone in amniotic fluid, in both male and female foetuses independent of maternal anxiety, plasma testosterone, gestational age, and time of collection. Foetal stress may be associated with increased foetal exposure to testosterone. However, maternal anxiety did not predict amniotic fluid cortisol or testosterone level. Thus, the role of these hormones in mediating the effect of maternal mood on foetal development in humans remains to be demonstrated.

Amniotic fluid testosterone: relationship with cortisol and gestational age

INTRODUCTION

Foetal exposure to testosterone is increasingly implicated in the programming of future reproductive and non-reproductive behaviour. Some outcomes associated with prenatal exposure to testosterone may be predicted from exposure to prenatal stress, suggesting a link between them. The peak serum levels of testosterone in the foetus are thought to be around 14-18 weeks' gestation, and we explored testosterone levels at different gestations. Although best investigated in foetal plasma, this is now difficult because of the decline in frequency of foetal blood sampling; in this study, we used amniotic fluid as a biomarker to investigate foetal exposure.

AIMS

To investigate the relationship between amniotic fluid testosterone, amniotic fluid cortisol, foetal gender, and gestational age.

METHODS

Paired amniotic fluid and maternal plasma samples were collected from 264 pregnant women undergoing amniocentesis between 15 and 37 weeks' gestation (median 17 weeks [119 days]). Total testosterone and cortisol in amniotic fluid, and total plasma testosterone (maternal) were measured by radioimmunoassay.

RESULTS

Amniotic fluid testosterone levels were higher in male than in female foetuses, with a median (interquartile range) of 0.85 nmol/l (0.60-1.17 nmol/l) and 0.28 nmol/l (0.175-0.45 nmol/l), respectively. No relationship between amniotic fluid testosterone and gestational age was detected in either sex. Amniotic fluid testosterone correlated positively with amniotic fluid cortisol in both sexes (r = 0.30 male foetuses, r = 0.33 female foetuses, P < 0.001 for both), and remained significant in multivariate analysis.

CONCLUSION

Testosterone in amniotic fluid did not change with gestation in the second and third trimester, raising questions about the timing of the reported early peak in the male foetus. The positive correlation between cortisol and testosterone in amniotic fluid suggests that increased foetal exposure to cortisol may also be associated with increased exposure to testosterone.

Enhanced neuronal differentiation in a three-dimensional collagen-hyaluronan matrix

Efficient 3D cell systems for neuronal induction are needed for future use in tissue regeneration. In this study, we have characterized the ability of neural stem/progenitor cells (NS/PC) to survive, proliferate, and differentiate in a collagen type I-hyaluronan scaffold. Embryonic, postnatal, and adult NS/PC were seeded in the present 3D scaffold and cultured in medium containing epidermal growth factor and fibroblast growth factor-2, a condition that stimulates NS/PC proliferation. Progenitor cells from the embryonic brain had the highest proliferation rate, and adult cells the lowest, indicating a difference in mitogenic responsiveness. NS/PC from postnatal stages down-regulated nestin expression more rapidly than both embryonic and adult NS/PC, indicating a faster differentiation process. After 6 days of differentiation in the 3D scaffold, NS/PC from the postnatal brain had generated up to 70% neurons, compared with 14% in 2D. NS/PC from other ages gave rise to approximately the same proportion of neurons in 3D as in 2D (9-26% depending on the source for NS/PC). In the postnatal NS/PC cultures, the majority of betaIII-tubulin-positive cells expressed glutamate, gamma-aminobutyric acid, and synapsin I after 11 days of differentiation, indicating differentiation to mature neurons. Here we report that postnatal NS/PC survive, proliferate, and efficiently form synapsin I-positive neurons in a biocompatible hydrogel.

Ontogeny of foetal exposure to maternal cortisol using midtrimester amniotic fluid as a biomarker

OBJECTIVE

There is increasing evidence that antenatal stress has long-lasting effects on child development, but there is less accord on the mechanisms and the gestational window of susceptibility. One possible mechanism is by foetal exposure to maternal cortisol. To explore this, we investigated the relationship between cortisol in maternal plasma and amniotic fluid, and any moderating influence of gestational age.

PATIENTS AND MEASUREMENTS

Two hundred and sixty-seven women awaiting amniocentesis for karyotyping were studied. Samples were collected between 0900 and 1730 h. Gestational age was determined to the nearest day by ultrasound biometry and time of collection noted to the nearest 15 min. Total cortisol was measured by radioimmunoassay in paired amniotic fluid and maternal blood samples (n = 267) [gestation range 15-37 weeks, median 17 weeks (119 days)].

RESULTS

Both maternal and amniotic fluid cortisol levels increased with gestation (r = 0.25, P < 0.001; r = 0.33 P < 0.001, respectively). Amniotic fluid cortisol was positively correlated with time of collection (r = 0.22, P < 0.001) and negatively with maternal age (r =-0.24, P < 0.001). There was a positive correlation between amniotic fluid cortisol with maternal plasma levels (r = 0.32, P < 0.001), which persisted after multivariate analysis controlling for gestation, time of collection and maternal age. The association appeared to be dependent on gestational age, being nonsignificant at 15-16 weeks' gestation and increasing in strength thereafter.

CONCLUSION

This study shows a positive correlation between maternal and amniotic fluid cortisol levels, which becomes robust from 17 to 18 weeks onwards. The results provide support for the hypothesis that alterations in maternal cortisol may be reflected in amniotic fluid levels from this gestation.

Maternal anxiety at amniocentesis and plasma cortisol

OBJECTIVES

To assess whether anticipation of amniocentesis is linked with maternal anxiety, and whether this anxiety is associated with increased maternal plasma cortisol.

METHODS

Two hundred and fifty-four women awaiting a morning amniocentesis for karyotyping (gestation range 15-37 weeks, median 17 weeks) completed Spielberger state and trait anxiety inventory (STAI) questionnaires, and provided blood samples immediately before the procedure for cortisol assay. Six hundred and five women at mean gestation of 20 weeks, attending the same hospital for routine ultrasound but not for amniocentesis, also completed Spielberger STAI questionnaires and served as a comparison group for the anxiety ratings.

RESULTS

Mean state and trait anxiety scores (+/- SD) in the comparison group of 605 women at mean gestation of 20 weeks were 36.1 +/- 10.2 (range 20-70) and 35.6 +/- 8.9 (range 20-73), respectively. The mean state anxiety score (+/-SD) of 49.8 +/- 14.0 (range 20-77) of the amniocentesis group was considerably higher than the comparison group (p < 0.001), although the mean trait anxiety score in the amniocentesis group was similar at 36.4 +/- 8.6 (range 21-60). The state, but not trait, anxiety correlated with plasma cortisol (r = 0.176, p = 0.005). Maternal cortisol in the amniocentesis group increased with gestational age (r = 0.310, p < 0.001), whereas state anxiety scores showed no significant change with increase in gestational age (r = - 0.042, ns). Multivariate analysis demonstrated that maternal state anxiety was positively correlated with plasma cortisol independent of gestation and time of collection.

CONCLUSION

Women awaiting amniocentesis experience a high state anxiety associated with modestly increased plasma cortisol.

Extramedullary hematopoiesis in a child with hereditary spherocytosis: an uncommon cause of an adrenal mass

We report a case of extramedullary hematopoiesis presenting as an adrenal mass in a young male with hereditary spherocytosis. The unilateral adrenal mass was discovered during an abdominal ultrasound performed for jaundice. CT and MR imaging were subsequently performed, followed by an excisional biopsy at the time of splenectomy and cholecystectomy. Although extramedullary hematopoiesis is a rare cause of an adrenal mass, the diagnosis must be considered in any patient with a history of a congenital hemolytic disorder such as hereditary spherocytosis. In this regard, the morbidity of an unnecessary procedure may be avoided.

Physical training in Syndrome X: physical training counteracts deconditioning and pain in Syndrome X

OBJECTIVES

The aim of this study was to evaluate the effects of exercise training and body-awareness training in female patients with Syndrome X.

BACKGROUND

Patients with Syndrome X, defined as effort-induced angina pectoris, a positive exercise test and a normal coronary angiogram, suffer from a chronic pain disorder. We hypothesized that this disorder results in physical deconditioning with decreased exertional pain threshold.

METHODS

Twenty-six patients were randomly assigned to two training groups (A, B) and a control group (C). Group A (n = 8) started, after baseline measurements, with eight weeks of body-awareness training followed by eight weeks of exercise training on a bicycle ergometer three times a week for 30 min at an intensity of 50% of peak work rate. Group B (n = 8) performed only eight weeks of exercise training. Group C (n = 10) acted as controls without any intervention whatsoever. The effects on exercise performance, hormonal secretion, vascular function, adenosine sensitivity and quality of life were evaluated.

RESULTS

Body-awareness training did not change the pain response. The two training groups did not differ in effects of exercise training. Exercise capacity before training was below the gender- and age-matched reference range and improved by 34% with training to a level not different from the reference range. Onset of pain was delayed by 100% from 3 +/- 2 to 6 +/- 3 min (p < 0.05) while maximum pain did not change. Thus the pain-response-to-exercise curve was shifted to the right. Syndrome X patients showed a hypersensitivity to low-dose adenosine infusion compared to healthy age- and gender-matched controls (p < 0.0001) that did not change with exercise training. Endothelium-dependent blood flow increase was at baseline within reference range and tended to increase (p < 0.06) following training. In Group A the concentration of cortisol in urine decreased by 53% after body-awareness training (p < 0.05), and this change from baseline remained after physical exercise training (p < 0.05). A similar decrease occurred with only exercise training (Group B).

CONCLUSIONS

Physical deconditioning with lower exertional threshold for pain is a prominent feature in Syndrome X. Physical training in Syndrome X results in an increased exercise capacity with lesser anginal pain. We suggest physical training as an effective treatment in Syndrome X.

Passive harmonic mode-locked soliton fiber laser stabilized by an optically pumped saturable Bragg reflector

Stabilization of passive harmonic mode locking is achieved for what is believed to be the first time in an Er-Yb soliton fiber laser by optical pumping of the semiconductor saturable absorber above the bandgap. The results show 35-dB mode suppression of undesired harmonics.

Cantor set fractals from solitons

We show how a nonlinear system that supports solitons can be driven to generate exact (regular) Cantor set fractals. As an example, we use numerical simulations to demonstrate the formation of Cantor set fractals by temporal optical solitons. This fractal formation occurs in a cascade of nonlinear optical fibers through the dynamical evolution from a single input soliton.

Phase I clinical trials of aroA aroD and aroA aroD htrA attenuated S. typhi vaccines; effect of formulation on safety and immunogenicity

PBCC211, an aroA aroD derivative of S. typhi strain CDC10-80, was tested in phase I trials as a single dose typhoid fever vaccine. Three different vaccine preparations, reconstituted lyophilized bacteria, freshly grown bacteria or lyophilized bacteria reconstituted from sachets, were orally administered to a total of 86 adult volunteers. An aroA aroD htrA strain, PBCC222, was also tested in 38 volunteers. Formulation impacted on the determination of a safe and immunogenic dose; reconstituted lyophilized cultures required higher doses than the broth cultures to stimulate seroconversion. In general, doses which seroconverted the majority of group members produced undesirable symptoms regardless of attenuation or formulation. The inability to separate the presence of symptoms from achieving significant immunogenicity in these aroA aroD or aroA aroD htrA strains precludes their use as single dose typhoid vaccines in the formulations tested. Multiple doses of these strains at a lower, safe level may be effective as vectors for foreign antigens.

Characterization of photodamage to Escherichia coli in optical traps

Optical tweezers (infrared laser-based optical traps) have emerged as a powerful tool in molecular and cell biology. However, their usefulness has been limited, particularly in vivo, by the potential for damage to specimens resulting from the trapping laser. Relatively little is known about the origin of this phenomenon. Here we employed a wavelength-tunable optical trap in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay. Single cells of Escherichia coli were tethered to a glass coverslip by means of a single flagellum: such cells rotate at rates proportional to their transmembrane proton potential (Manson et al.,1980. J. Mol. Biol. 138:541-561). Monitoring the rotation rates of cells subjected to laser illumination permits a rapid and quantitative measure of their metabolic state. Employing this assay, we characterized photodamage throughout the near-infrared region favored for optical trapping (790-1064 nm). The action spectrum for photodamage exhibits minima at 830 and 970 nm, and maxima at 870 and 930 nm. Damage was reduced to background levels under anaerobic conditions, implicating oxygen in the photodamage pathway. The intensity dependence for photodamage was linear, supporting a single-photon process. These findings may help guide the selection of lasers and experimental protocols best suited for optical trapping work.

Optimizing hospital-based home care for dying cancer patients: a population-based study

In many reports the percentage of home deaths in cancer is based on selected populations. In this population-based study all cancer patients who died within 12 months within a specified area were studied (n = 108). This area is covered by hospital-based home care (HBHC) on a 24-h basis, which doctors available by day and at night. Forty people (37%) out of the total cancer population died in their own homes. Another 11% would theoretically have been ideal candidates for home care at the end of life. Thus, a home death rate of about 50% of the cancer patients is a realistic figure, and much higher than the usual 5-15% reported, provided that an effective HBHC is offered.

Observation of the breakup of a prechirped N-soliton in an optical fiber

We present what is believed to be the first experimental evidence showing the breakup of a chirped N-soliton pulse into an ordered train of fundamental solitons, as predicted by theory. We also present numerical experiments that confirm this phenomenon. Implications for optical communications systems that use chirped pulses are discussed.

Photon-number squeezing in the normal-dispersion regime

We experimentally demonstrate the generation of amplitude-squeezed light in the normal-dispersion regime and measure by direct detection 1.7+/-0.1 dB (33%) and, with correction for linear losses, 2.5+/-0.2 dB (47%) of noise reduction below the shot-noise level. The dependence of the noise behavior on dispersion is investigated both experimentally and theoretically.

Dose selection for carcinogenicity studies of pharmaceuticals: systemic exposure to phenacetin at carcinogenic dosage in the rat

A systemic exposure-based alternative to the MTD (maximally tolerated dose) for high-dose selection in carcinogenicity studies of pharmaceuticals has been accepted by the ICH (International Conference on Harmonisation of Technical Requirements for the Registration of Pharmaceuticals for Human Use). As a result of a retrospective analysis performed by the U.S. FDA (United States Food and Drug Administration), a rat/human relative systemic exposure ratio of 25 is proposed by the ICH as an acceptable pharmacokinetic endpoint for high-dose selection. For use as a dose selection criterion, it is particularly important that the magnitude of the relative systemic exposure ratio should be sufficient to detect human pharmaceuticals classified by IARC (International Agency for Research on Cancer, World Health Organization) as known (category 1) or probable (category 2A) human carcinogens. For one of these, phenacetin (an IARC 2A compound and a rat carcinogen), a systemic exposure ratio of 15 was calculated by the FDA. This calculation was based on a number of extrapolations. The present study reports the actual systemic exposure to phenacetin in the rat under conditions mimicking the conditions in the carcinogenicity study used by the FDA to calculate the relative systemic exposure ratio of 15. The ratio was found to be 7, indicating that the carcinogenic potential of this particular probable human carcinogen could be detected at a considerably lower systemic exposure ratio than that proposed by the ICH.

Amplitude-squeezed solitons from an asymmetric fiber interferometer

We experimentally demonstrate a new scheme for generating amplitude-squeezed solitons in an asymmetric fiber Sagnac loop. We measure by direct detection what is to our knowledge a record reduction of 5.7+/-0.1 dB (73%) and, with corrections for linear losses, 6.2+/-0.1 dB (76%) in the photon-number fluctuations below the shot-noise level. The same scheme is also shown to generate significant classical noise reduction and is limited by Raman effects in fiber.

Stable multigigahertz pulse-train formation in a short-cavity passively harmonic mode-locked erbium/ytterbium fiber laser

We demonstrate a short-cavity erbium-ytterbium fiber laser that is passively mode locked by a saturable Bragg reflector with a fundamental repetition rate of 235 MHz . The laser operates in the soliton regime and under passive harmonic mode locking with 11 pulses in the cavity and produces output pulse trains at 2.6 GHz with transform-limited 270-fs pulses and 1.6 mW of average power. Within the cavity the multiple pulses form a stable pattern with fixed, nearly equal pulse-to-pulse temporal spacings, causing the output pulse train to have timing offsets of less than 15 ps. A slow gain-recovery model is proposed to explain the pulse-train self-organization.

Spontaneous duodenal hematoma in a patient with Glanzmann's thrombasthenia

Spontaneous intramural duodenal hematoma is a rare problem, most commonly seen in children who have coagulation disorders. A child who had Glanzmann's thrombasthenia, a disorder of platelet function, presented with signs and symptoms of duodenal obstruction. Nonoperative management of an obstructing duodenal hematoma was successful and potentially life-threatening surgery was avoided.

True fundamental solitons in a passively mode-locked short-cavity Cr(4+):YAG laser

We demonstrate a self-starting, passively mode-locked short-cavity Cr(4+):YAG laser that supports fundamental intracavity solitons over wide ranges of cavity group-velocity dispersion and pulse energies. The total dispersion and nonlinear effects are small enough that stable, N=1 soliton pulses are generated. Equally spaced multiple pulsing is also observed, with fundamental soliton behavior preserved. Regions of bistability exist where, at a constant cavity dispersion, the laser can produce transform-limited pulses of a different width and energy. The laser produces 200-fs pulses at approximately 0.9-, 1.8-, and 2.7-GHz repetition rates with a total of 82 mW of average output power.

Saturable Bragg reflector self-starting passive mode locking of a Cr(4+):YAG laser pumped with a diode-pumped Nd:YVO(4) laser

We demonstrate self-starting passive mode locking of a Cr (4+):YAG laser, using an intracavity nonlinear mirror as a saturable absorber. The pump source is a diode-pumped Nd:YVO(4) laser. Output pulses are centered at 1541 nm, with 26-nm spectral bandwidth and 110-fs pulse width. Output powers of 70 mW are obtained with 8 W of pump power. This mode locking technique is compared with Kerr-lens mode locking.

Series: current issues in mutagenesis and carcinogenesis, No. 65. The genotoxicity and carcinogenicity of paracetamol: a regulatory (re)view

The publication of several studies reporting genotoxic effects of paracetamol, one of the world's most popular over-the-counter drugs, has raised the question of regulatory action. Paracetamol does not cause gene mutations, either in bacteria or in mammalian cells. There are, however, published data giving clear evidence that paracetamol causes chromosomal damage in vitro in mammalian cells at high concentrations and indicating that similar effects occur in vivo at high dosages. Available data point to three possible mechanisms of paracetamol-induced genotoxicity: (1) inhibition of ribonucleotide reductase; (2) increase in cytosolic and intranuclear Ca2+ levels; (3) DNA damage caused by NAPQI after glutathione depletion. All mechanisms involve dose thresholds. Studies of the relationship between genotoxicity and toxic effects in the rat (induction of micronuclei in rat bone marrow including dose-response relationship, biotransformation of paracetamol at different dosages, concomitant toxicity and biochemical markers) have recently been completed. These studies, which employed doses ranging from the dose resulting in human therapeutic peak plasma levels to highly toxic doses, give convincing evidence that genotoxic effects of paracetamol appear only at dosages inducing pronounced liver and bone marrow toxicity and that the threshold level for genotoxicity is not reached at therapeutic dosage. Reliable studies on the ability of paracetamol to affect germ cell DNA are not available. However, based on the amount of drug likely to reach germ cells and the evidence of thresholds, paracetamol is not expected to cause heritable damage in man. Various old and poorly designed long-term studies of paracetamol in the mouse and rat have given equivocal results. A few of these studies showed increased incidence of liver and bladder tumours at hepatotoxic doses. National Toxicology Program (U.S.A.) feeding studies have shown that paracetamol is non-carcinogenic when given at non-hepatotoxic doses up to 300 mg/kg/d to the rat and up to 1000 mg/kg/d to the mouse. Taking into account the knowledge of the hepatotoxicity and metabolism of paracetamol and the existence of thresholds for its genotoxicity, the animal studies do not indicate a carcinogenic potential at non-hepatotoxic dose levels. Based on this updated assessment of the genotoxicity and carcinogenicity of paracetamol, it is concluded that there is no need for regulatory action.

Clinical and epidemiological investigations of Acinetobacter genomospecies 3 in a neonatal intensive care unit

A prospective study of Acinetobacter isolates from a neonatal intensive care unit was performed for 24 months. Fifty-six isolates were obtained from 21 patients, and another eight were obtained from environmental specimens. Infection due to Acinetobacter organisms was established for 16 patients, 6 with septicemia, 9 with pneumonia, and 1 with a wound infection. Further investigations were performed with 38 representative isolates. Twenty-nine isolates were identified as unnamed DNA-DNA hybridization group (genomospecies) 3, three were identified as genomospecies 2 (Acinetobacter baumannii), one was identified as genomospecies 5 (Acinetobacter junii), three were identified as genomospecies 14, and two were unclassified. Eight distinguishable protein profiles, coded I through VIII, were found by cell envelope protein electrophoresis. Profile V, a common profile, was observed for 17 isolates that had been recovered from 11 patients and 1 dust specimen. These isolates, all of which belonged to genomospecies 3, had similar antibiograms and biotypes. This study has revealed that genomospecies 3 can be associated with infection and be spread in hospitals.

Squeezing in a fiber interferometer with a gigahertz pump

We report 5.1 dB of squeezing from a fiber interferometer pumped with a 1-GHz pulse source that successfully eliminates guided-acoustic-wave Brillouin scattering in significant frequency regimes. The pulse source is a diode-pumped Nd:YLF laser actively mode locked at 1.314 microm. The squeezing results are consistent with the limits imposed by the Gaussian pulse shape and the detection quantum efficiency.

Toxicological studies of the false morel (Gyromitra esculenta): embryotoxicity of monomethylhydrazine in the rat

The embryotoxic and teratogenic potential of monomethylhydrazine (MMH), a toxic component of the widely consumed false morel (Gyromitra esculenta), was studied in rat. Groups of pregnant Sprague-Dawley rats received MMH as a constant i.v. infusion via implanted osmotic minipumps (1.2, 3.0, 4.2, 6.0, 9.0 or 13.2 mg MMH/kg bw/day) on days 6-13 of pregnancy, or as a single intragastric bolus (1 mg MMH/kg/bw or 5 mg MMH/kg/bw) on day 6 of pregnancy. Controls received corresponding amounts of saline. The average maternal serum concentrations, measured during the infusion treatment with a sensitive HPLC method, ranged from 0.072 micrograms MMH/ml (lowest dose) to 0.60 microgram MMH/ml (highest dose). The average serum levels measured 45 min after the intragastric application (peak levels) were 0.28 microgram MMH/ml and 1.6 microgram MMH/ml, respectively. Serum concentrations of MMH corresponding to those measured in the lower dose groups in this study were seen in pilot studies after a single mushroom meal in human volunteers. A dose-dependent, statistically significant increase in the number of resorptions was seen in all but the lowest dose group after the infusion of MMH. In addition, except for the two lowest doses, there was a dramatic, dose-dependent decrease in the pregnancy rate as compared to controls, with no pregnancies occurring at the two highest dose level groups. The decreased pregnancy rate was probably due to preimplantation loss which was shown to occur after a single intragastric bolus dose of MMH (5 mg/kg bw).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal dietary supplementation with selenite on the postnatal development of rat offspring exposed to methyl mercury in utero

Female Sprague-Dawley rats were fed a control standard diet or a selenite (Se) supplemented diet (1.3 p.p.m. Se) for 8 weeks before mating and during gestation and lactation. Blood glutathione peroxidase activity (GSH-Px) was measured as a biomarker of Se in dames. After mating, the females from two dietary groups were divided into three subgroups (6 groups with 10 animals in each) given 0 (vehicle), 2 or 6 mg/kg methyl mercury (MeHg) by gavage on days 6-9 of gestation. Day 2 post parturition all litters were standardized to 6 pups per litter and remaining pups were used for determination of blood and brain total Hg contents. Behavioural testing was performed at two months of age. The results of the study showed that supplementing the diet with Se partly antagonized some adverse effects of the MeHg such as hypoactivity especially in the high MeHg dose group. There were no changes in physical development or body weight except a tendency to decreased body weight in offspring of mothers exposed to 6 mg Hg/kg. The GSH-Px activity was significantly increased in animals fed on Se supplemented diet. The dietary Se supplementation resulted in considerably increased concentrations of mercury in the blood of the offspring despite milder signs of CNS toxicity and no increase in brain concentrations of mercury.

CT of blunt chest trauma in children

While trauma is still the leading cause of death in the pediatric age range, it is surprising how little the CT appearances of pediatric chest injury have been investigated in the literature. We have reviewed the CT findings of blunt chest trauma in 44 children for whom chest CT examinations were requested to investigate the extent of intrathoracic injury. We noted a propensity for pulmonary contusions to be located posteriorly or posteromedially, and for them to be anatomically nonsegmental and crescentic in shape. This is possibly attributable to the relatively compliant anterior chest wall in children. The CT appearances of other major thoracic injuries are described, including pulmonary lacerations, pneumothoraces, malpositioned chest tubes, mediastinal hematomas, aortic injury, tracheobronchial injury, hemopericardium, and spinal injuries with paraspinal fluid collections. Children demonstrating findings incidental to the actual injury yet important to the subsequent therapy are also presented. We conclude that, in the event of clinically significant blunt chest trauma, the single supine chest examination in the trauma room is insufficient to adequately identify the extent of intrathoracic injury. With the exception of concern for aortic injury for which aortography is indicated, a dynamically enhanced CT scan of the thorax should be performed as clinically significant findings may result in altered therapy.

Studies of embryotoxicity and the incidence of external malformations after continuous intravenous infusion of alpha-chaconine in pregnant rats

Embryotoxicity and effects on the incidence of external malformations of the major potato glycoalkaloid alpha-chaconine (alpha-cha) were studied in rats. Pregnant Sprague-Dawley rats (n = 17) were given a continuous intravenous infusion of alpha-cha via implanted osmotic minipumps (1.7 mg/kg/day), to maintain a stable blood concentration on days 6-13 of gestation. Control animals received physiological saline solution or were left untreated, respectively. Blood serum levels of alpha-cha were monitored at selected time intervals during the treatment using a specific HPLC method. The foetal body weights and the number of resorbed or dead foetuses per litter in the alpha-cha treated group were not significantly different from the control groups. No case of malformation was detected among 143 foetuses inspected in the treated group. The average maternal blood serum concentration of alpha-cha measured during the experiment was 340 ng/ml. This is more than 20 times the average peak serum level previously reported for human volunteers after intake of potatoes with a total glycoalkaloid content at the upper safe limit for acute adverse effects. The results support the view that potato glycoalkaloids, at levels normally found in potatoes, do not present a risk for teratogenicity in humans.

Functional benefit of an adaptive myoelectric prosthetic hand compared to a conventional myoelectric hand

Eight patients with a traumatic unilateral upper limb amputation, who used conventional myoelectric prostheses, were also fitted with a commercially available myoelectric prosthetic hand with an adaptive grip, in order to compare the functional benefit of the two types of prostheses. Comparisons were made regarding width of grip, force of grip, scores in a standardised grip function test and prosthesis preference. The conventional prosthesis showed significantly better results regarding these parameters. The adaptive hand does not appear to be fully developed for practical use in prosthetic rehabilitation.

Methylation of rat and mouse DNA by the mushroom poison gyromitrin and its metabolite monomethylhydrazine

Consumption of false morel (Gyromitra esculenta Fr.) has been associated not only with acute poisoning, but also with a carcinogenic risk. The hydrolysis of acetaldehyde-N-methyl-N-formylhydrazone (gyromitrin, the main toxic component of false morel) results in the formation of the methylating agents N-methyl-N-formylhydrazine (MFH) and N-methylhydrazine (MMH) (by further hydrolysis of MFH). This study reports traces of N-7-methylguanine (N7MeGu) in liver DNA from mice and a rat treated with gyromitrin. After repeated administration of MMH, N7MeGu was identified in rat liver DNA. In mice exposed to MMH according to a dosing scheme identical to that reported to induce tumours in this species, O6-methylguanine was present in liver and kidney DNA. The results indicate that a relatively low carcinogenic risk is associated with false morel consumption. The risk may be greater in individuals with a decreased detoxification rate (acetylation) of MFH, in whom larger amounts of MMH are formed from gyromitrin.

Mutations in the two flagellin genes of Rhizobium meliloti

The previously cloned DNA fragment which complements the behavioral defects of the che-1 and che-3 mutations of Rhizobium meliloti codes for two nearly identical (93%) flagellin genes. A wild-type copy of one of the two genes (flaA) but not the other (flaB) can complement the mutations. The behavior and flagellar morphology of newly isolated strains carrying insertion and deletion mutations or various combinations of these mutations demonstrated that either gene product alone can form functional flagellar filaments but when both gene products are present they interact in the formation of filaments. Both the nucleic acid sequences of the genes and the deduced amino acid sequences of the proteins from strain Rm1021 showed significant differences from the sequences determined previously for strain RU10406. (E. Pleier and R. Schmitt, J. Bacteriol. 171:1467-1475, 1989). The tandem arrangement of the two genes is stable, although in vitro recombination between them gave rise to a strain with wild-type behavior.

Squeezing in fibers with optical pulses

A novel method of squeezing with optical pulses in a fiber ring reflector is demonstrated experimentally. Squeezing of greater than 5 +/- 0.3 dB has been observed. The pump is separated from the squeezed radiation with a fiber ring reflector and can be reused, in principle fully, as the local oscillator. The detection is at low frequencies (35-85 kHz) and is unaffected by guided-acoustic-wave Brillouin scattering.

Demonstration of optical switching by means of solitary wave collisions in a fiber ring reflector

We have demonstrated the use of solitary wave collisions in optical pulse switching. Our apparatus consisted of a fiber ring with 11 sections of polarization-maintaining fiber, with successive sections fusion spliced with the axes rotated 90 deg. The configuration yielded enhanced transmission (autocorrelation contrast ratio 2.82:1), in agreement with expectation for this number of sections and the unoptimized fiber coupler that was used. Design criteria for complete switching are presented.

Milk transfer of inorganic mercury to suckling rats. Interaction with selenite

The transport of mercury into rat milk, and uptake in the suckling offspring was studied after peroral administration of inorganic mercury to lactating control rats, and to rats fed selenite in the diet. On day 8, 9, 10, or 11 of lactation, dams were administered a single oral dose of 0.1, 0.4, 0.7, 1.3, or 5.8 mg Hg/kg bw labeled with 203mercuric acetate. There was a linear relationship between mercury concentrations in dam's plasma and milk. The level of mercury in milk was approximately 25% of the level in plasma. After 3 d, milk levels were reduced to half the levels at 24 h. In the suckling offspring, exposed to mercury via milk during 3 d, the mercury level in blood was approximately 1% of the level in maternal blood. Mercury concentration in milk was linearly correlated to the levels in kidney, liver, and brain in the suckling offspring after 3 d exposure to mercury via milk. Selenite treatment of rats, 1.3 micrograms Se/g diet for 5 mo, resulted in increased transport of mercury to milk, probably because of increased plasma levels of mercury. However, selenite treatment of the dams did not cause any increased tissue levels of mercury in the suckling offspring.

Life events: the reliability of rating changes in routine and environment

Alterations in routine and environment can affect clinical state in patients suffering from cognitive impairment. A method for rating life events for changes in routine and environment is described and found to be highly reliable even when used by inexperienced raters after brief training.

Effects of dietary sodium selenite supplementation on salicylate-induced embryo- and fetotoxicity in the rat

The effects of dietary supplementation with sodium selenite (3.0 or 4.5 ppm Se) for 8 weeks prior to and throughout gestation on sodium salicylate induced embryo- and fetotoxicity (resorptions, fetal deaths, malformations, fetal weight reduction) have been studied in the rat. Salicylate was administered either as daily intragastric bolus doses of 250 mg/kg on gestation days 6-13 (maternal peak and trough salicylate levels of 222-120 micrograms/ml whole-blood) or via constant rate intravenous infusion of 150 mg/kg/day on the same gestation days via implanted osmotic minipumps (stable average maternal blood salicylate level of 120 micrograms/ml = human antirheumatic concentration). Both gavage and infusion of salicylate resulted in an increase of resorptions and fetal deaths as well as a decrease of fetal body weights. Gavage with salicylate also produced about 50% malformed fetuses. Selenite did not protect against the embryotoxic effects of salicylate administered as intragastric bolus doses. However, selenite was found to significantly increase fetal survival rate in the infusion experiment, although it did not counteract the decrease of fetal body weight. In animals fed selenite only, no negative effects on fetal body development were noted. The protective effect of selenite against salicylate induced embryotoxicity is difficult to explain, since very little is known about the mechanisms of salicylate embryotoxicity and the biological effects of selenium. However, an interaction between selenium, via glutathione peroxidase, and salicylate at the level of prostaglandin synthesis could be possible.

PET imaging in obsessive compulsive disorder with and without depression

Obsessive compulsive disorder (OCD) is a classic psychoneurosis which is frequently complicated by major depression. Recent positron emission tomography neuroimaging studies, when taken in the context of a variety of other data, implicate a brain dysfunction involving the orbital prefrontal cortex and the striatum in the mediation of OCD behaviors and those of the related Gilles de la Tourette's syndrome. The anterolateral prefrontal cortex is implicated in the secondary major depressions often complicating OCD.

Accumulation and turnover of metabolites of toluene and xylene in nasal mucosa and olfactory bulb in the mouse

Autoradiography of male mice following inhalation of the radioactively labelled solvents, toluene, xylene, and styrene, revealed an accumulation of non-volatile metabolites in the nasal mucosa and olfactory bulb of the brain. Since no accumulation occurred after benzene inhalation, it was assumed that the activity represented aromatic acids, which are known metabolites of these solvents. This was supported by the finding that also radioactive benzoic acid (main metabolite of toluene) and salicylic acid accumulated in the olfactory bulb. High-performance liquid chromatography revealed that after toluene inhalation (for 1 hr), nasal mucosa and olfactory bulb contained mainly benzoic acid, with a strong accumulation in relation to blood plasma, and considerably less of its glycine conjugate, hippuric acid. After xylene inhalation, on the other hand, methyl hippuric acid dominated over the non-conjugated metabolite, toluic acid. The results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain. The toxicological significance of these results remains to be studied.

Faculty and student perceptions of effective clinical teachers: an extension study

This extension study was conducted to (1) identify which characteristics of the effective clinical teacher are deemed most important by nursing students and faculty; (2) determine whether previous findings remain valid (are transferable); and (3) investigate whether the perception of effective teaching behavior shifts as students advance toward graduation. The research tool, a two-part questionnaire developed by Brown, was circulated among students and instructors at a university college of nursing in southwestern Ohio. The first section listed 20 characteristics of teachers to be rated, using a Likert-type scale, from "of most importance" to "of no importance." The second section required subjects to select and rank in order the five most important characteristics from the list of 20. Descriptive analysis was applied to the data, and findings were compared with those of Brown. The study suggests that both faculty and students favor articulate, knowledgeable clinical instructors who are "objective and fair" in student evaluation. There is a high degree of similarity between the responses of faculty and students, but differences emerge. Both value skills involving the student-faculty relationship over skills centering on the professional or personal attributes of the instructor. However, faculty respondents appear to place a higher value on instructor interest in patients, and students are more concerned with communication-related attributes. Faculty members place a greater value on showing interest in patients than do students. The results, when compared with Brown's findings, appear largely transferable, but significant differences appear. For example, faculty members ranked characteristics dealing with the clinical instructor's relationship with students to be more important than those dealing with professional competence--the opposite of Brown's results. This study shows the need for nursing institutions to implement programs to foster and to promote uniformly identified effective clinical teaching characteristics. Given the special challenges of clinical nursing education, graduate programs should also seek to teach the skills identified as most effective, and persons with the skills perceived as effective should be urged to enter clinical instruction and should be rewarded for success in this important area.