A central role of the BK potassium channel in behavioral responses to ethanol in C. elegans

The activities of many neuronal proteins are modulated by ethanol, but the fundamental mechanisms underlying behavioral effects of ethanol remain unclear. To identify mechanisms responsible for intoxication, we screened for Caenorhabditis elegans mutants with altered behavioral responses to ethanol. We found that slo-1 mutants, which were previously recognized as having slightly uncoordinated movement, are highly resistant to ethanol in two behavioral assays. Numerous loss-of-function slo-1 alleles emerged from our screens, indicating that slo-1 has a central role in ethanol responses. slo-1 encodes the BK potassium channel. Electrophysiological analysis shows that ethanol activates the channel in vivo, which would inhibit neuronal activity. Moreover, behaviors of slo-1 gain-of-function mutants resemble those of ethanol-intoxicated animals. These results demonstrate that selective activation of BK channels is responsible for acute intoxicating effects of ethanol in C. elegans. BK channel activation may explain a variety of behavioral responses to ethanol in invertebrate and vertebrate systems.

High-temperature silicate volcanism on Jupiter's moon Io

Infrared wavelength observations of Io by the Galileo spacecraft show that at least 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on Earth today. In at least one case, the eruption near Pillan Patera, two independent instruments on Galileo show that the lava temperature must have exceeded 1700 kelvin and may have reached 2000 kelvin. The most likely explanation is that these lavas are ultramafic (magnesium-rich) silicates, and this idea is supported by the tentative identification of magnesium-rich orthopyroxene in lava flows associated with these high-temperature hot spots.

Natural variation in the npr-1 gene modifies ethanol responses of wild strains of C. elegans

Variation in the acute response to ethanol between individuals has a significant impact on determining susceptibility to alcoholism. The degree to which genetics contributes to this variation is of great interest. Here we show that allelic variation that alters the functional level of NPR-1, a neuropeptide Y (NPY) receptor-like protein, can account for natural variation in the acute response to ethanol in wild strains of Caenorhabditis elegans. NPR-1 negatively regulates the development of acute tolerance to ethanol, a neuroadaptive process that compensates for effects of ethanol. Furthermore, dynamic changes in the NPR-1 pathway provide a mechanism for ethanol tolerance in C. elegans. This suggests an explanation for the conserved function of NPY-related pathways in ethanol responses across diverse species. Moreover, these data indicate that genetic variation in the level of NPR-1 function determines much of the phenotypic variation in adaptive behavioral responses to ethanol that are observed in natural populations.

The development of terahertz sources and their applications

The terahertz region of the electromagnetic spectrum spans the frequency range between the mid-infrared and the millimetre/microwave. This region has not been exploited fully to date owing to the limited number of suitable (in particular, coherent) radiation sources and detectors. Recent demonstrations, using pulsed near-infrared femtosecond laser systems, of the viability of THz medical imaging and spectroscopy have sparked international interest; yet much research still needs to be undertaken to optimize both the power and bandwidth in such THz systems. In this paper, we review how femtosecond near-infrared laser pulses can be converted into broad band THz radiation using semiconductor crystals, and discuss in depth the optimization of one specific generation mechanism based on ultra-fast transport of electrons and holes at a semiconductor surface. We also outline a few of the opportunities for a technology that can address a diverse range of challenges spanning the physical and biological sciences, and note the continuing need for the development of solid state, continuous wave, THz sources which operate at room temperature.

A preliminary evaluation of the cognitive and motor effects of pediatric HIV infection in Zairian children

Fourteen asymptomatic HIV-infected Zairian children under 2 years of age displayed social and motor developmental deficits on the Denver Developmental Screening Test when compared with 20 HIV-negative cohorts born to HIV-infected mothers and 16 control children. In a second study, 11 infected children over 2 years of age had sequential motor and visual-spatial memory deficits on the Kaufman Assessment Battery for Children and motor development deficits on the Early Childhood Screening Profiles. HIV infection affects central nervous system structures mediating motor and spatial memory development, even in seemingly asymptomatic children. Furthermore, maternal HIV infection compromises the labor-intensive provision of care in the African milieu and undermines global cognitive development in even uninfected children.

A pilot study of 131I monoclonal antibodies in the therapy of leptomeningeal tumors

A pilot study was performed to investigate the toxicity and therapeutic effect of radiolabeled antibody administered intrathecally in patients with leptomeningeal tumors. Five patients who failed conventional therapy received between 11 mCi and 40 mCi of radiolabeled antibody. The choice of antibody varied depending on the immunophenotype of the tumor. Therapy was well tolerated generally, with minimal acute toxicity. Four of five patients achieved an objective response to treatment that has been sustained for a period varying from 7 months to 2 years. No clinical signs of chronic toxicity have been observed in patients 1 and 2 years after therapy.

Label-free electrochemical impedance biosensor to detect human interleukin-8 in serum with sub-pg/ml sensitivity

Biosensors with high sensitivity and short time-to-result that are capable of detecting biomarkers in body fluids such as serum are an important prerequisite for early diagnostics in modern healthcare provision. Here, we report the development of an electrochemical impedance-based sensor for the detection in serum of human interleukin-8 (IL-8), a pro-angiogenic chemokine implicated in a wide range of inflammatory diseases. The sensor employs a small and robust synthetic non-antibody capture protein based on a cystatin scaffold that displays high affinity for human IL-8 with a K_D of 35±10 nM and excellent ligand specificity. The change in the phase of the electrochemical impedance from the serum baseline, ∆θ(ƒ), measured at 0.1 Hz, was used as the measure for quantifying IL-8 concentration in the fluid. Optimal sensor signal was observed after 15 min incubation, and the sensor exhibited a linear response versus logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. A detection limit of around 90 fg/ml, which is significantly lower than the basal clinical levels of 5–10 pg/ml, was observed. Our results are significant for the development of point-of-care and early diagnostics where high sensitivity and short time-to-results are essential.

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A label-free electrochemical impedance-based sensor for the detection of human interleukin-8 (IL-8) in full serum was developed.

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Detection limit of 90 fg/ml and time-to-result of 15 min was found.

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A large dynamic range of the sensor was observed, with sensor response linear vs logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml.

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The sensor employs a small and robust synthetic non-antibody capture protein, with high stability and excellent ligand specificity.

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Findings are particularly relevant for the development of point-of-care and early diagnosis sensors where high sensitivity and short time-to-results are essential.

Preparation and properties of brush-border membrane vesicles from human small intestine

This study describes a simple and rapid method for the preparation of brush-border membrane vesicles from intestinal biopsies. The specific activities of sucrase, amino peptidase N, and alkaline phosphatase in these vesicles were the same as those in vesicles prepared from intestinal segments. The vesicles from all the regions of the small intestine can transport D-glucose in an Na+-dependent manner. The rates of transport of D-glucose presented here are far higher than previously reported. The method should have a wide applicability to studies of transport mechanisms and the distribution of transport processes within the intestine.

Urinary albumin excretion in school children

Concentrations of albumin were measured by an enzyme linked immunoassay in 24 hour urine collections (divided into day and night-time samples) from 183 boys and 191 girls aged 4 to 16 years. The 24 hour albumin excretion rate and day and night-time albumin excretion rates all increased with age in both girls and boys. Albumin excretion during the day exceeded that at night in both girls and boys. Albumin excretion rates were higher in girls than boys during the day but there was no significant difference at night-time. The urinary albumin creatinine ratio showed no change with age, but was greater in girls than boys during the day and at night, and was also greater during the day than at night in both sexes. Graphs of normal values of albumin excretion rates and albumin creatinine ratios are provided.

Scalloped wings is the Lucilia cuprina Notch homologue and a candidate for the modifier of fitness and asymmetry of diazinon resistance

The Scalloped wings (Scl) gene of the Australian sheep blowfly, Lucilia cuprina, is shown to be the homologue of the Drosophila melanogaster Notch gene by comparison at the DNA sequence and genetic levels. A L. cuprina genomic fragment, which shows strong identity with the Notch (N) gene at the molecular level, hybridizes to the location of the Scl gene on polytene chromosomes. The two genes are functionally homologous; the dominant and recessive Notch-like phenotypes produced by mutations in the Scl gene allow these alleles to be classed as N-like or Abruptex-like. The Scl gene is under investigation as a candidate for the fitness and asymmetry Modifier (M) of diazinon resistance. We show that M affects the penetrance of wing and bristle phenotypes associated with two Scl alleles in a manner consistent with the M being an allele of Scl. In addition, we report a phenotypic interaction between the diazinon-resistance mutation, Rop-1, and the same alleles of Scl. We propose that the product of Rop-1, an esterase, may be involved in cell adhesion in developmental processes involving the Scl gene product.

The use of Fourier-transform infrared spectroscopy for the quantitative determination of glucose concentration in whole blood

Fourier-transform infrared transmission spectroscopy has been used for the determination of glucose concentration in whole blood samples from 28 patients. A 4-vector partial least-squares calibration model, using the spectral range 950-1200 cm(-1), yielded a standard-error-of-prediction of 0.59 mM for an independent test set. For blood samples from a single patient, we found that the glucose concentration was proportional to the difference between the values of the second derivative spectrum at 1082 cm(-1) and 1093 cm(-1). This indicates that spectroscopy at these two specific wavenumbers alone could be used to determine the glucose concentration in blood plasma samples from a single patient, with a prediction error of 0.95 mM.

A close-up look at Io from Galileo's near-infrared mapping spectrometer

Infrared spectral images of Jupiter's volcanic moon Io, acquired during the October and November 1999 and February 2000 flybys of the Galileo spacecraft, were used to study the thermal structure and sulfur dioxide distribution of active volcanoes. Loki Patera, the solar system's most powerful known volcano, exhibits large expanses of dark, cooling lava on its caldera floor. Prometheus, the site of long-lived plume activity, has two major areas of thermal emission, which support ideas of plume migration. Sulfur dioxide deposits were mapped at local scales and show a more complex relationship to surface colors than previously thought, indicating the presence of other sulfur compounds.

A preliminary evaluation of the cognitive and motor effects of pediatric HIV infection in Zairian children

Fourteen asymptomatic HIV-infected Zairian children under 2 years of age displayed social and motor developmental deficits on the Denver Developmental Screening Test when compared with 20 HIV-negative cohorts born to HIV-infected mothers and 16 control children. In a second study, 11 infected children over 2 years of age had sequential motor and visual-spatial memory deficits on the Kaufman Assessment Battery for Children and motor development deficits on the Early Childhood Screening Profiles. HIV infection affects central nervous system structures mediating motor and spatial memory development, even in seemingly asymptomatic children. Furthermore, maternal HIV infection compromises the labor-intensive provision of care in the African milieu and undermines global cognitive development in even uninfected children.

Ethanol metabolism and osmolarity modify behavioral responses to ethanol in C. elegans

BACKGROUND

Ethanol (EtOH) is metabolized by a 2-step process in which alcohol dehydrogenase (ADH) oxidizes EtOH to acetaldehyde, which is further oxidized to acetate by aldehyde dehydrogenase (ALDH). Although variation in EtOH metabolism in humans strongly influences the propensity to chronically abuse alcohol, few data exist on the behavioral effects of altered EtOH metabolism. Here, we used the nematode Caenorhabditis elegans to directly examine how changes in EtOH metabolism alter behavioral responses to alcohol during an acute exposure. Additionally, we investigated EtOH solution osmolarity as a potential explanation for contrasting published data on C. elegans EtOH sensitivity.

METHODS

We developed a gas chromatography assay and validated a spectrophotometric method to measure internal EtOH in EtOH-exposed worms. Further, we tested the effects of mutations in ADH and ALDH genes on EtOH tissue accumulation and behavioral sensitivity to the drug. Finally, we tested the effects of EtOH solution osmolarity on behavioral responses and tissue EtOH accumulation.

RESULTS

Only a small amount of exogenously applied EtOH accumulated in the tissues of C. elegans and consequently their tissue concentrations were similar to those that intoxicate humans. Independent inactivation of an ADH-encoding gene (sodh-1) or an ALDH-encoding gene (alh-6 or alh-13) increased the EtOH concentration in worms and caused hypersensitivity to the acute sedative effects of EtOH on locomotion. We also found that the sensitivity to the depressive effects of EtOH on locomotion is strongly influenced by the osmolarity of the exogenous EtOH solution.

CONCLUSIONS

Our results indicate that EtOH metabolism via ADH and ALDH has a statistically discernable but surprisingly minor influence on EtOH sedation and internal EtOH accumulation in worms. In contrast, the osmolarity of the medium in which EtOH is delivered to the animals has a more substantial effect on the observed sensitivity to EtOH.

Renal function in diabetes mellitus

Glomerular filtration rate, day and night-time albumin excretion, and blood pressure were estimated in 83 children with diabetes mellitus and compared with measures of glycaemic control, age, and duration of disease. Careful attention was paid to definition of normal values in age matched controls. The glomerular filtration rate was greater than normal, and correlated with duration of disease, but not with albumin excretion or blood pressure. Daytime albumin excretion correlated with duration of disease and glycosylated haemoglobin, but not with age, glomerular filtration rate, or blood pressure. Night-time albumin excretion was significantly raised and correlated with duration of disease, glycosylated haemoglobin, mean blood sugar concentration, and M value but not with age, glomerular filtration rate, or blood pressure. Diastolic blood pressure was significantly raised but was not correlated with any other measured variable. We have confirmed abnormalities of renal function in a children's diabetic clinic. The measurement of overnight albumin excretion rates may provide a sensitive early indicator of renal damage.

Terahertz time-domain spectroscopy of glucose and uric Acid

We report the use ofterahertz time-domain spectroscopy for thestudy of two therapeutic bio-molecules:glucose and uric acid. Terahertztransmission spectra of crystalline samplesof both molecules were measured between 0.1-3.0 THz using an evacuated spectroscopysystem. We propose that the stereo-isomersof glucose show spectral featuresoriginating from intermolecular vibrationalmodes, as do uric acid and its derivativemolecule, allantoin. In addition, wepresent a full temperature dependence ofthe terahertz absorption of L-glucose.

Carotid sinus hypersensitivity in patients presenting with syncope

In 23 patients (ages 44 to 81) presenting with syncope, vertigo, or transient amnesia, carotid sinus massage produced a significant bradycardia in association with symptoms. The 10 most severely symptomatic patients were studied electrophysiologically, including measurement of intracardiac conduction times and corrected sinus node recovery times, as well as with carotid sinus massage before and after atropine. The only detectable abnormality in five of this group was asystole produced by carotid sinus massage; the other five had, in addition, evidence of either sinuatrial disease or an intracardiac conduction defect. Cardiac pacing in these 10 patients completely abolished their symptoms. In a control group of 52 asymptomatic patients (ages 36 to 87), an abnormal response to carotid sinus massage was uncommon (2%).

The role of the BK channel in ethanol response behaviors: evidence from model organism and human studies

Alcohol abuse is a significant public health problem. Understanding the molecular effects of ethanol is important for the identification of at risk individuals, as well as the development of novel pharmacotherapies. The large conductance calcium sensitive potassium (BK) channel has emerged as an important player in the behavioral response to ethanol in genetic studies in several model organisms and in humans. The BK channel, slo-1, was identified in a forward genetics screen as a major ethanol target in C. elegans for the effects of ethanol on locomotion and egg-laying behaviors. Regulation of the expression of the BK channel, slo, in Drosophila underlies the development of rapid tolerance to ethanol and benzyl alcohol sedation. Rodent expression studies of the BK-encoding KCNMA1 gene have identified regulation of mRNA levels in response to ethanol exposure, and knock out studies in mice have demonstrated that the β subunits of the BK channel, β1 and β4, can modulate ethanol sensitivity of the channel in electrophysiological preparations, and can influence drinking behavior. In human genetics studies, both KCNMA1 and the genes encoding β subunits of the BK channel have been associated with alcohol dependence. This review describes the genetic data for a role for BK channels in mediating behavioral responses to ethanol across these species.

Intrathecal administration of 131I radiolabelled monoclonal antibody as a treatment for neoplastic meningitis

Fifteen patients with neoplastic meningitis received a single intrathecal injection of between 11 and 60 mCi of a 131I radiolabelled monoclonal antibody (MoAb), chosen for its immunoreactivity to tumour. Major toxicity was manifest as nausea, vomiting and headache (7/15 patients), reversible bone marrow suppression (3/8 patients) and seizures (2/15 patients). Nine patients were evaluable for either a tumour or clinical response. Six of these demonstrated an event-free response that was maintained for periods of between 7 and 26 months.

Chordomas--ultrastructure and immunohistochemistry: a report based on the examination of six cases

Six chordomas (three classic and three chondroid) were examined ultrastructurally and with a panel of monoclonal antibodies. The three classic tumours showed the presence of desmosomes and intermediate filaments on electron microscopy, findings which gave a direct positive correlation when the tumours were stained with monoclonal antibodies against low molecular weight cytokeratin proteins. These results suggest that chordomas are essentially epithelial neoplasms and underline the fact that monoclonal antibodies to cytokeratins cannot be used in the differential diagnosis of classic chordoma vs carcinoma. Furthermore, the epithelial characteristics are lost as the tumour undergoes chondroid differentiation.

Gender differences in HIV risk behaviour of injecting drug users in Edinburgh

A multi-site sample of currently-injecting drug users (IDUs) comprising 344 men and 136 women was recruited in Edinburgh. Sixty-seven per cent of the sample said they had at some time used injecting equipment already used by another person and 25% admitted doing so in the 6 months before interview. Whereas women who injected with used equipment obtained it predominantly from a sexual partner, for men the source was more often a close friend or someone whose HIV status they were unlikely to know. In the 6 months before interview, 40% of men, compared with 20% of women, had more than one heterosexual partner. This difference was associated with a higher proportion of men with steady partners also having casual partners. Women IDUs were more likely to have regular partners who injected (57% vs 26%). Though sharing of injecting equipment has already diminished in Edinburgh, further measures are needed to eliminate it. For injectors here, the risk of infection from unprotected heterosexual intercourse may now be greater than that from sharing injecting equipment, particularly for women. Other methods of encouraging changes in sexual behaviour need to be investigated and successful ones promoted.

Loss of RAB-3/A in Caenorhabditis elegans and the mouse affects behavioral response to ethanol

The mechanisms by which ethanol induces changes in behavior are not well understood. Here, we show that Caenorhabditis elegans loss-of-function mutations in the synaptic vesicle-associated RAB-3 protein and its guanosine triphosphate exchange factor AEX-3 confer resistance to the acute locomotor effects of ethanol. Similarly, mice lacking one or both copies of Rab3A are resistant to the ataxic and sedative effects of ethanol, and Rab3A haploinsufficiency increases voluntary ethanol consumption. These data suggest a conserved role of RAB-3-/RAB3A-regulated neurotransmitter release in ethanol-related behaviors.

Chloride intracellular channels modulate acute ethanol behaviors in Drosophila, Caenorhabditis elegans and mice

Identifying genes that influence behavioral responses to alcohol is critical for understanding the molecular basis of alcoholism and ultimately developing therapeutic interventions for the disease. Using an integrated approach that combined the power of the Drosophila, Caenorhabditis elegans and mouse model systems with bioinformatics analyses, we established a novel, conserved role for chloride intracellular channels (CLICs) in alcohol-related behavior. CLIC proteins might have several biochemical functions including intracellular chloride channel activity, modulation of transforming growth factor (TGF)-β signaling, and regulation of ryanodine receptors and A-kinase anchoring proteins. We initially identified vertebrate Clic4 as a candidate ethanol-responsive gene via bioinformatic analysis of data from published microarray studies of mouse and human ethanol-related genes. We confirmed that Clic4 expression was increased by ethanol treatment in mouse prefrontal cortex and also uncovered a correlation between basal expression of Clic4 in prefrontal cortex and the locomotor activating and sedating properties of ethanol across the BXD mouse genetic reference panel. Furthermore, we found that disruption of the sole Clic Drosophila orthologue significantly blunted sensitivity to alcohol in flies, that mutations in two C. elegans Clic orthologues, exc-4 and exl-1, altered behavioral responses to acute ethanol in worms and that viral-mediated overexpression of Clic4 in mouse brain decreased the sedating properties of ethanol. Together, our studies demonstrate key roles for Clic genes in behavioral responses to acute alcohol in Drosophila, C. elegans and mice.