Neurological complications of coeliac disease: what is the evidence?

Coeliac disease is a chronic immune-mediated disorder that primarily affects the gastrointestinal tract. There is an inflammatory response in the intestine to the ingestion of gluten which improves with a gluten-free diet. Many patients, especially adults, may be asymptomatic or have only extraintestinal symptoms at onset without any of the classical coeliac symptoms. In the last two decades there have been increasing numbers of reports describing neurological complications of coeliac disease, especially ataxia, peripheral neuropathy and epilepsy. This literature has become quite controversial, with disputes over the definition of coeliac disease and gluten sensitivity, whether neurological complications are caused by coeliac disease or are epiphenomena, and whether the proposed complications respond to a gluten-free diet. This review uses an evidence-based approach to critically assess this literature and provides guidelines for the evaluation and management of these patients.

Characterization of transformed cells and tumors by proton nuclear magnetic resonance spectroscopy.

Cultured acute lymphoblastic leukemic cells give a well-resolved proton nuclear magnetic resonance spectrum characteristic of isolated plasma membranes. We demonstrate that the signals, in the spectrum of whole cells, arise predominantly from the plasma membrane and that cells transformed by pokeweed mitogen have membranes which are significantly less rigid than are normal human peripheral blood lymphocytes. Normal thymus, malignant thymus, and a leukemic T-cell line have been compared by proton nuclear magnetic resonance spin echo experiments, and the normal thymus was found to differ. Cells transformed by the Epstein-Barr virus can also be characterized and shown to differ from the leukemically transformed cells by spin echo experiments. Since no probe molecule was required to obtain these results, this is the first definitive evidence that the structure and fluidity of the plasma membranes change as a result of transformation of lymphocytes. Proton nuclear magnetic resonance spectroscopy can now be used to compare the effect of different mitogens on T- and B-lymphocytes as well as to monitor the effects of drugs, metals, etc., on the plasma membrane of transformed lymphocytes.

In vivo resetting of the hamster circadian clock by 5-HT7 receptors in the suprachiasmatic nucleus.

Serotonin (5-HT) has been strongly implicated in the regulation of the mammalian circadian clock located in the suprachiasmatic nuclei (SCN); however, its role in behavioral (nonphotic) circadian phase resetting remains elusive. Central to this issue are divergent lines of evidence that the SCN may, or may not, be a target for the phase-resetting effects of 5-HT. We have addressed this question using a novel reverse-microdialysis approach for timed perfusions of serotonergic and other agents to the Syrian hamster SCN with durations equivalent to the increases in in vivo 5-HT release during phase-resetting behavioral manipulations. We found that 3 hr perfusions of the SCN with either 5-HT or the 5-HT(1A,7) receptor agonist 2-dipropylamino-8-hydroxy-1,2,3,4-tetrahydro-naphthalene (8-OH-DPAT) at midday advanced the phase of the free-running circadian rhythm of wheel-running assessed using an Aschoff type II procedure. Phase shifts induced by 8-OH-DPAT were enhanced more than threefold by pretreatment with the 5-HT synthesis inhibitor para-chlorophenylalanine. Phase advances induced by SCN 8-OH-DPAT perfusion were significantly inhibited by the 5-HT(2,7) receptor antagonist ritanserin and by the more selective 5-HT(7) receptor antagonist DR4004, implicating the 5-HT(7) receptor in mediating this phase resetting. Concurrent exposure to light during the 8-OH-DPAT perfusion abolished the phase advances. Furthermore, coperfusion of the SCN with TTX, which blocked in vivo 5-HT release, did not suppress intra-SCN 8-OH-DPAT-induced phase advances. These results indicate that 5-HT(7) receptor-mediated phase resetting in the SCN is markedly influenced by the degree of postsynaptic responsiveness to 5-HT and by photic stimulation. Finally, 5-HT may act directly on SCN clock cells to induce in vivo nonphotic phase resetting.

Influenza virus: an NMR study of mechanisms involved in infection.

High resolution 1H-NMR spectroscopy has been used to study the infection of chicken embryo fibroblasts by influenza virus. Marked changes in the NMR spectrum occur when infectious influenza virus is introduced into the fibroblasts and these changes appear to depend upon the presence of active neuraminidase (EC 3.2.1.18). A crude preparation of neuraminidase from Vibrio cholerae is able to effect similar changes. Only minor spectral changes are observed in the absence of culture medium or when the viral genome material is inactivated by beta-propiolactone. Similarly, little change is seen in the NMR spectrum when amantadine, which is thought to inhibit uncoating of the virus inside the cell, or actinomycin D, which inhibits cellular nucleic acid metabolism, are incubated with fibroblasts prior to the addition of virus. The results suggest that neuraminidase, in co-operation with a factor in the infectious process, initiates a cellular event which can be monitored by NMR. The nature of this cellular mechanism is unknown, but further studies are under way to determine its importance in viral infection.

Protein inhibitor of activated STAT-1 (signal transducer and activator of transcription-1) is a nuclear receptor coregulator expressed in human testis.

An androgen receptor (AR) interacting protein was isolated from a HeLa cell cDNA library by two-hybrid screening in yeast using the AR DNA+ligand binding domains as bait. The protein has sequence identity with human protein inhibitor of activated signal transducer and activator of transcription (PIAS1) and human Gu RNA helicase II binding protein (GBP). Binding of PIAS1 to human AR DNA+ligand binding domains was androgen dependent in the yeast liquid beta-galactosidase assay. Activation of binding by dihydrotestosterone was greater than testosterone > estradiol > progesterone. PIAS1 binding to full-length human AR in a reversed yeast two hybrid system was also androgen dependent. [35S] PIAS1 bound a glutathione S-transferase-AR-DNA binding domain (amino acids 544-634) fusion protein in affinity matrix assays. In transient cotransfection assays using CV1 cells with full-length human AR and a mouse mammary tumor virus luciferase reporter vector, there was an androgen-dependent 3- to 5-fold greater increase in luciferase activity with PIAS1 over that obtained with an equal amount of control antisense cDNA or mutant PIAS1. Constitutive transcriptional activity of the AR N-terminal+DNA binding domain was increased 6-fold by PIAS1. PIAS1 also enhanced glucocorticoid receptor transactivation in response to dexamethasone but inhibited progesterone-induced progesterone receptor transactivation in the same assay system. mRNA for PIAS1 was highly expressed in testis of human, monkey, rat, and mouse. In rat testis the onset of PIAS1 mRNA expression coincided with the initiation of spermatogenesis between 25-30 days of age. Immunostaining of human and mouse testis with PIAS1-specific antiserum demonstrated coexpression of PIAS1 with AR in Sertoli cells and Leydig cells. In addition, PIAS1 was expressed in spermatogenic cells. The results suggest that PIAS1 functions in testis as a nuclear receptor transcriptional coregulator and may have a role in AR initiation and maintenance of spermatogenesis.

Effect of monoclonal anti-neuraminidase antibodies on the kinetic behavior of influenza virus neuraminidase.

Neuraminidase from the recombinant influenza virus A/NWSHA-Tokyo/3/67NA HON2 has been shown to exhibit non-Michaelis-Menten kinetics. The multiphasic behaviour was demonstrated for both the isolated neuraminidase heads and for the intact virus. Interaction of the enzyme with two monoclonal anti-neuraminidase antibodies (WANA 1 and RANA 1), which recognize separate antigenic determinants on the molecule, resulted in hyperbolic kinetic behaviour. While both antibodies abolished the multiphasic kinetics of the enzymic reaction, only WANA 1 altered the Vmax and Km values, indicating that it may in some way inhibit the interaction of enzyme and substrate.

HE2beta and HE2gamma, new members of an epididymis-specific family of androgen-regulated proteins in the human.

HE2 is an epididymis-specific sperm-binding secretory protein. We isolated a family of HE2-related complementary DNAs from a human caput/corpus library. The transcripts code for identical 71-amino acid N-termini and different C-termini, and 5'- and 3'-untranslated regions. Compared with the original HE2, HE2beta and HE2gamma proteins have a 25-amino acid deletion near the C-terminus, and HE2gamma isoforms have a second deletion. These frame-shifting deletions result in C-termini differing in length, amino acid sequence, including number of cysteines, and isoelectric point. Identical sequences and deletion start and stop points indicate the HE2 isoforms are derived from alternative splicing of 8 or more exons of a single gene. Northern hybridization revealed that the 0.9-kb messenger RNA (mRNA) is most abundant in human caput; there is much less of it (20%) in corpus and little (<5%) in cauda. In castrated Macaca mulatta, HE2 mRNA decreased to 10% of sham-operated levels. Testosterone replacement maintained HE2 mRNA 3- to 5-fold higher than castrate levels, indicating its androgen dependence. Immunohistochemical staining revealed that the beta1 form is highly expressed in principal cells of the initial segment and caput. It is secreted into the lumen and binds to the sperm surface in the postacrosomal and neck regions. The beta2 form is expressed in principal cells primarily in efferent ducts.

Primate epididymis-specific proteins: characterization of ESC42, a novel protein containing a trefoil-like motif in monkey and human.

Epididymal secreted proteins promote sperm maturation and fertilizing capacity by interacting with sperm during passage through the epididymis. Here we investigate the molecular basis of sperm maturation by isolating cDNA clones for novel epididymis-specific expressed sequences. Thirty-six novel cDNAs were isolated and sequenced from a subtracted Macaca mulatta epididymis library. The clones encode proteins with a range of motifs characteristic of protein-modifying enzymes, protease inhibitors, hydrophobic ligand-binding and transport proteins, extracellular matrix-interacting proteins, and transcription regulatory factors. The full length coding sequences were obtained for 11 clones representing a range of abundance levels. Expression of each is regionally localized and androgen regulated. The most abundant, ESC42, contains a cysteine-rich region similar to the signature binding domain of the trefoil family of motogenic wound repair proteins. The monkey and human proteins are nearly 90% identical. Immunohistochemical staining revealed that the protein is most abundant in the epithelium of the caput and is also present in the lumen and bound to sperm. The ESC42 gene, located on chromosome 20q11, contains two exons encoding two nearly identical predicted signal peptides and a third exon encoding the rest of the protein.

Respiratory, cardiovascular, and metabolic effects of enteral hyperalimentation: influence of formula dose and composition.

Respiratory, cardiovascular, and metabolic changes were monitored during balance studies in undernourished patients receiving continuous enteral formula feeding. The nutrient solutions, either high carbohydrate (83% of kcal) or high fat (50% of kcal), were administered at doses ranging from 2.7 to 6.0 X 10(-2) kcal X kg fat free body mass-1 X min-1. For both formulas, the observed physiological changes between fasting and the lower rates of energy infusion (ie, maintenance-slow growth) were either zero or relatively small. As formula dose was advanced into the rapid repletional range, physiological changes were more pronounced; there were linear increases in oxygen consumption, carbon dioxide production, minute ventilation, heat production, heat release, nitrogen balance, and change in heart rate from the base-line (all p less than 0.05 for both formulas). The rate at which carbon dioxide production, minute ventilation, and heat production increased with advancing energy infusion rate was also greater for the high carbohydrate formula relative to the high fat formula (p less than 0.02, less than 0.07, and less than 0.06, respectively). The physiological changes caused by continuous intragastric feeding are therefore a function of formula infusion rate and composition. Knowledge of these changes can be applied to patients treated for semistarvation who suffer respiratory or cardiac insufficiency.

Human energy requirements: overestimation by widely used prediction equation.

Basal energy expenditure accounts for a large component of energy losses, and a clinical estimate of this form of thermogenesis is usually derived from a prediction equation. The most widely used prediction equation was developed in 1919 by Harris and Benedict. The energy requirements of healthy and diseased individuals are often estimated from application of this formula. Using a direct gradient-layer calorimeter and two different indirect calorimeters, our two centers found that the Harris-Benedict equation overestimated basal energy requirements by 10 to 15% (X +/- SD, 12.3 +/- 11%) in 201 studies of healthy men and women. These results raise questions regarding the accuracy of predicting an individual's energy requirements.

Efflux of alanine by Giardia intestinalis.

Giardia intestinalis trophozoites synthesise and then secrete large amounts of alanine into the external medium during growth. This efflux of alanine was studied by preloading cells with L-[2,3-3H]alanine, and determining efflux of radiolabel from intact trophozoites. The efflux of alanine was also determined by measurement of alanine concentration in trophozoites and external medium using high pressure liquid chromatography amino acid analysis. Over the temperature range 4 degrees C to 37 degrees C there was a slow efflux of alanine, but this efflux was greatly stimulated by a number of amino acids structurally similar to alanine, notably glycine, L-serine, L-threonine, L-asparagine and L-glutamine. In contrast, 2-aminoisobutyrate, D-amino acids, and other naturally occurring amino acids had no effect. Those amino acids which stimulated the efflux of intracellular alanine are the same amino acids which inhibited uptake of extracellular alanine. This concordance suggests that an alanine antiport functions for both the influx and efflux of alanine, and acts to maintain a balance between intracellular and extracellular alanine concentrations.

Effect of monocular visual loss upon stability of gaze.

Using the eye-coil/magnetic field method, we measured horizontal and vertical movements of both eyes in four patients with monocular loss of vision while they attempted steady, binocular fixation of a visual target. We also measured gaze stability in two normal subjects while they fixed upon a target monocularly, and in one patient with congenital, bilateral blindness. In the patients with monocular visual loss, gaze instability was greater in the blind eye, both vertically and horizontally, compared either with their seeing eye or with nonviewing eyes of control subjects. Gaze instability due to monocular blindness resulted from: (1) low-frequency, low-amplitude, bidirectional drifts that were more prominent vertically; and (2) unidirectional drifts, with nystagmus, that were more prominent in the horizontal plane. Gaze-evoked nystagmus, however, was not a feature of monocular blindness. Thus, the gaze instability of monocular blindness may reflect disruption of: (1) a monocular visual stabilization system; (2) fusional vergence mechanisms; or (3) both. In contrast, bilateral congenital blindness led to nystagmus with horizontal and vertical components and a wandering null point, indicative of an abnormal neural integrator.

Evidence for two distinct members of the amylase gene family in the yellow fever mosquito, Aedes aegypti.

Genomic DNA fragments encoding a salivary gland-specific alpha-amylase gene, Amylase I (Amy I), and an additional amylase, Amylase II (AmyII) of the yellow fever mosquito, Aedes aegypti, were isolated and characterized. Two independently isolated DNA fragments, G34-F and G34-14A, encode polymorphic alleles of Amy I. A 3.2 kilobase (kb) EcoR I fragment of G34-F, F2, has been sequenced in its entirety and contains 832 base pairs (bp) of the 5'-end, non-coding and putative promoter regions that are adjacent to 2.4 kb of the Amy I coding region. One intron, 59 bp in length, is found towards the 3'-end of the clone. A third genomic clone, 3A, corresponding to Amy II, was sequenced and shown not to contain the primary DNA sequence that encodes the 260 amino acid region that uniquely characterizes the amino terminal end of the Amy I product. Amy I was assigned by restriction fragment length polymorphism (RFLP) mapping to chromosome 2 (23.0 cM) and Amy II to chromosome 1 (44.0 cM). Amy I and Amy II are highly polymorphic and there may be multiple linked copies at each locus. Comparisons between Amy I and Amy II are presented for the putative promoter and conceptual translation products. The identification of two distinct amylase genes and their separate linkage assignments provides evidence for a multigene family of alpha-amylases in Ae. aegypti.

The piggyBac element is capable of precise excision and transposition in cells and embryos of the mosquito, Anopheles gambiae.

The piggyBac transposable element was tested for transposition activity in plasmid-based excision and inter-plasmid transposition assays to determine if this element would function in Anopheles gambiae cells and embryos. In the Mos55 cell line, precise excision of the piggyBac element was observed only in the presence of a helper plasmid. Excision occurred at a rate of 1 event per 1000 donor plasmids screened. Precise excision of the piggyBac element was also observed in injected An. gambiae embryos, but at a lower rate of 1 excision per 5000 donor plasmids. Transposition of the marked piggyBac element into a target plasmid occurred in An. gambiae cells at a rate of 1 transposition event per 24,000 donor plasmids. The piggyBac element transposed in a precise manner, with the TTAA target site being duplicated upon insertion, in 56% of transpositions observed, and only in the presence of the piggyBac helper. The remaining transpositions resulted in a deletion of target sequence, a novel observation for the phenomenon of piggyBac element insertion. 'Hot spots' for insertion into the target plasmid were observed, with 25 of 34 events involving one particular site. These results are the first demonstration of the precise mobility of piggyBac in this malaria vector and suggest that the lepidopteran piggyBac transposon is a candidate element for germline transformation of anopheline mosquitoes.

Effectiveness of medical necessity guidelines in reducing cost of oxygen therapy.

Concern for the rising costs of respiratory therapy in patient care caused a third party payor to implement reimbursement guidelines for inhospital delivery of oxygen (O2) therapy. While these guidelines are physiologically appropriate, their effectiveness in cost reduction has not been documented. To determine the effect of similar guidelines on the cost of O2 therapy, we prospectively studied 77 noncritically ill patients for whom physicians ordered O2. If pretreatment arterial blood gas determinations had not been ordered, ear oximetry was performed. The cost of O2 therapy to each patient, as based on total patient charges for O2, appliances, delivery, and assessment of oxygenation throughout hospitalization, was computed in three ways: Cost A, actual charges for O2 therapy initiated by physician order; Cost B, projected charges for O2 therapy using physiologic guidelines alone (PaO2 less than 60 mm Hg or SaO2 less than 90 percent); and Cost C, projected charges for O2 therapy using combined physiologic and clinical guidelines (PaO2 less than 60 mm Hg, SaO2 less than 90 percent or clinical record reasonably indicating hypoxemia). Of the 77 patients, 23 (30 percent) met the physiologic guidelines and 48 (62 percent) met the combined physiologic and clinical guidelines. The cost (total patient charges) of O2 therapy can be reduced through implementation of medical necessity guidelines, but physiologic guidelines alone appear more cost effective than combined physiologic and clinical guidelines.

The use of viscoelastometry to determine survival curves for intact genomes.

Viscoelastometry enables one to determine both size (Mr) and number concentration (L1) of intact genome molecules in solution. Comparison of four parameters, corrected for shear stress, as functions of 60Co gamma-ray dose showed that (1) the principal retardation time (tau 11,0) remained constant, indicating that intact genomes (bacteriophage T4c) were being measured; (2) the principal recoil (gamma 11,r,0) decreased with dose directly proportionately to (and determining) L1; (3) both the total recoil (gamma r,0) and the recoil area (Ar,0), under conditions of high solvent viscosity decreased with dose almost as sensitively as gamma 11,r,0. The DNAD37 was 540 +/- 25 Gy and the biological PFUD37 was 410.1 +/- 4.5 Gy yielding 75.9 +/- 3.6% of inactivating events explicable by one double-strand break (DSB) per genome. This value is comparable to Freifelder's [Virology 36, 613-619 (1981)] value of 86% for phage T4r48+, and the Frankenberg-Schwager et al. (Br. J. Cancer, in press) value of 0.84 DSB/cell/lethal event in diploid mutant rad54-3 yeast under conditions restrictive for DSB repair. Therefore, T4c may be an excellent model system for DNA damage repair studies with relevance to pro- and eukaryotes. Viscoelastometry, working near its lower size limit, provided precise estimates of the proportion of genomes lacking DSBs. It is not subject to the molecular deformation upper size limitations of the other biophysically understood size measurement methods (e.g., sedimentation rotor speed dependence). Therefore, it should be the method of choice for the study of genomes larger than those of the T even bacteriophages.

Bioenergetic and metabolic response to continuous v intermittent nasoenteric feeding.

Resting thermal energy losses and metabolic balances of N, K, P, Ca, Na, and Mg were compared during continuous and intermittent nasoenteric formula infusion in four healthy men. Each feeding protocol lasted 1 week in a 4-week double crossover experiment. The initial feeding schedule was established randomly. Continuous nasoenteric formula infusion produced no increase in thermal energy losses above the fasting level; energy expenditure fell with sleep to the same extent as with intermittent feeding. Thermal losses were similar during intermittent feeding with the exception of the thermic effect of food that produced an additional average energy loss of 115.7 kcal/d. The total resting and sleeping 24-hour energy expenditure was significantly lower (P less than .01) during continuous formula infusion (means +/- SD for n = 8 balance periods, 1344 +/- 119 kcal) compared to intermittent feeding (1457 +/- 179 kcal). No significant differences in nutrient absorption or balances of N, Na, Ca, and Mg were detected between the two feeding protocols. In contrast, continuous infusion of formula was accompanied by negative balances of K and the cytosolic portion of P; weight balance was slightly negative. Weight, K, and cytosolic P balances were all positive during intermittent feeding (P = NS, less than 0.01, and P less than .05 compared to respective continuous infusion periods). Hence, 1 week of continuous nasogastric formula infusion is associated with similar nutrient absorption, a significant reduction in thermal energy losses, and equivalent protein (N) balance relative to intermittent feeding. Differences in weight balance between the two feeding protocols can be ascribed largely to fluid and mineral shifts. These results suggest that energy requirements are lower during continuous formula infusion by about 100 kcal/d compared to regular meal ingestion.

Sleep deprivation stimulates serotonin release in the suprachiasmatic nucleus.

Recent literature suggests that sleep deprivation has a general stimulatory effect on the central serotonergic system. Herein we report that in hamsters, sleep deprivation induced by gentle handling for 3 h under dim red light at midday stimulates serotonin release in the suprachiasmatic nuclei by as much as 171%. Basal levels of 5-HT release are re-established within 1 h after cessation of treatment. Sleep deprivation also evokes phase advances of the circadian activity rhythm averaging 2 h. When sleep deprivation is undertaken in bright light, serotonin release is stimulated, but phase-shifting is greatly inhibited. It is therefore proposed that if the phase-resetting response to sleep deprivation is mediated by increased serotonin release, light inhibits the phase-resetting effect by blocking the postsynaptic or other downstream actions of serotonin.

Enteral nutritional support. Metabolic, cardiovascular, and pulmonary interrelations.

Continuous enteral feeding produces changes in metabolism and cardiopulmonary function. Recognition of these effects and the potential complications of tube feeding is essential prior to initiation of therapy. This article reviews the enteral feeding technique and associated metabolic and technical complications in detail.

Microhabitat use in a mediterranean riverine fish assemblage : Fishes of the lower Matarraña.

Over a 22 month period Barbus graellsii, Chondrostoma toxostoma, Cyprinus carpio, Esox lucius, Gobio gobio, and Leuciscus cephalus displayed non-random microhabitat use in the Rio Mattarraña, Spain and generally were overrepresented in deep microhabitats with low or undetectable flow velocities. Substrate composition did not strongly affect microhabitat use outside of its covariation with depth and velocity. Most seasonal differences in microhabitat use were attributable to seasonal changes in microhabitat availability, although all species selectively occupied deeper microhabitats during Spring 1984, 1985, and Early Summer 1984. Smaller specimens of B. graellsii, Ch. toxostoma, G. gobio, and L. cephalus all occurred closer to the substrate than larger specimens. Smaller specimens also tended to occupy shallower areas with greater amounts of erosional substrates (except for Ch. toxostoma). Assemblage members occupied statistically distinct microhabitats and could be classified as: 1) upper water column (L. cephalus), 2) mid-water column (Ch. toxostoma, C. carpio), 3) lower water column (B. graellsii), or 4) benthic (G. gobio, E. lucius). We hypothesize that the observed pattern of vertical segregation was produced by a combination of predator avoidance and differential evolutionary adaptation rather than by interspecific competition for space.