Changes to insulin sensitivity in glucose clearance systems and redox following dietary supplementation with a novel cysteine-rich protein: A pilot randomized controlled trial in humans with type-2 diabetes

We recently developed a novel keratin-derived protein (KDP) rich in cysteine, glycine, and arginine, with the potential to alter tissue redox status and insulin sensitivity. The KDP was tested in 35 human adults with type-2 diabetes mellitus (T2DM) in a 14-wk randomised controlled pilot trial comprising three 2×20 g supplemental protein/day arms: KDP-whey (KDPWHE), whey (WHEY), non-protein isocaloric control (CON), with standardised exercise. Outcomes were measured morning fasted and following insulin-stimulation (80 mU/m2/min hyperinsulinaemic-isoglycaemic clamp). With KDPWHE supplementation there was good and very-good evidence for moderate-sized increases in insulin-stimulated glucose clearance rate (GCR; 26%; 90% confidence limits, CL 2%, 49%) and skeletal-muscle microvascular blood flow (46%; 16%, 83%), respectively, and good evidence for increased insulin-stimulated sarcoplasmic GLUT4 translocation (18%; 0%, 39%) vs CON. In contrast, WHEY did not effect GCR (-2%; -25%, 21%) and attenuated HbA1c lowering (14%; 5%, 24%) vs CON. KDPWHE effects on basal glutathione in erythrocytes and skeletal muscle were unclear, but in muscle there was very-good evidence for large increases in oxidised peroxiredoxin isoform 2 (oxiPRX2) (19%; 2.2%, 35%) and good evidence for lower GPx1 concentrations (-40%; -4.3%, -63%) vs CON; insulin stimulation, however, attenuated the basal oxiPRX2 response (4%; -16%, 24%), and increased GPx1 (39%; -5%, 101%) and SOD1 (26%; -3%, 60%) protein expression. Effects of KDPWHE on oxiPRX3 and NRF2 content, phosphorylation of capillary eNOS and insulin-signalling proteins upstream of GLUT4 translocation AktSer437 and AS160Thr642 were inconclusive, but there was good evidence for increased IRSSer312 (41%; 3%, 95%), insulin-stimulated NFκB-DNA binding (46%; 3.4%, 105%), and basal PAK-1Thr423/2Thr402 phosphorylation (143%; 66%, 257%) vs WHEY. Our findings provide good evidence to suggest that dietary supplementation with a novel edible keratin protein in humans with T2DM may increase glucose clearance and modify skeletal-muscle tissue redox and insulin sensitivity within systems involving peroxiredoxins, antioxidant expression, and glucose uptake.

Microscopic Analysis of the Water/Glycerol/EO30PS System in Bulk and on a Solid Substrate

Surfactant systems are often employed in cosmetic formulations where they dry on skin as a surface, thereby becoming increasingly concentrated systems. To better understand this drying process, we focused on the difference of self-assembled structures of the water/glycerol/polyoxyethylene (30) phytosteryl ether (EO30PS) system in bulk and on a solid substrate because the interaction between the substrate and the surfactant may have a substantial effect on the self-assembly, which may be related to the bulk structure but in detail may also differ strongly from the bulk situation. In bulk, small-angle neutron scattering (SANS) experiments showed that with increasing loss of water, the degree of ordering increases but changes of the aggregate structure are rather small. The results indicate that ellipsoidal micelles of EO30PS are densely packed and simply become more ordered in bulk during the drying process. On the other hand, neutron reflectometry revealed that EO30PS molecules adsorb onto a Si surface in the form of bilayers and analysis indicates that at a high concentration (c = 20 wt %), there are on average two bilayers (a double bilayer) on the Si substrate. The adsorbed membrane structure of EO30PS is rather thin with respect to its hydrophobic part, indicating tilted molecules, containing only some solvent, and being not highly ordered. These experimental results then allow for a much deeper understanding of the structural properties of practical formulations as they are applied, for instance, in cosmetic lotions.

Chemoinformatics View on Bitter Taste Receptor Agonists in Food

Food compounds with a bitter taste have a role in human health, both for their capability to influence food choice and preferences and for their possible systemic effect due to the modulation of extra-oral bitter taste receptors (TAS2Rs). Investigating the interaction of bitter food compounds with TAS2Rs is a key step to unravel their complex effects on health and to pave the way to rationally design new additives for food formulation or drugs. Here, we propose a collection of food bitter compounds, for which in vitro activity data against TAS2Rs are available. The patterns of TAS2R subtype-specific agonists were analyzed using scaffold decomposition and chemical space analysis, providing a detailed characterization of the associations between food bitter tastants and TAS2Rs.

Caloric restriction increases levels of taurine in the intestine and stimulates taurine uptake by conjugation to glutathione

Our previous study indicated increased levels of taurine-conjugated bile acids (BA) in the intestine content of mice submitted to caloric restriction (CR). In the current project, we found increased levels of free taurine and taurine conjugates, including glutathione (GSH)-taurine, in CR compared to ad libitum fed animals in the mucosa along the intestine but not in the liver. The levels of free GSH were decreased in the intestine of CR compared to ad libitum fed mice. However, the levels of oxidized GSH were not affected and were complemented by the lack of changes in the antioxidative parameters. Glutathione-S transferases (GST) enzymatic activity was increased as was the expression of GST genes along the gastrointestinal tract of CR mice. In the CR intestine, addition of GSH to taurine solution enhanced taurine uptake. Accordingly, the expression of taurine transporter (TauT) was increased in the ileum of CR animals and the levels of free and BA-conjugated taurine were lower in the feces of CR compared to ad libitum fed mice. Fittingly, BA- and GSH-conjugated taurine levels were increased in the plasma of CR mice, however, free taurine remained unaffected. We conclude that CR-triggered production and release of taurine-conjugated BA in the intestine results in increased levels of free taurine what stimulates GST to conjugate and enhance uptake of taurine from the intestine.

Protein-protein interactions at a glance: Protocols for the visualization of biomolecular interactions

Protein-protein interactions (PPIs) play a key role in many biological processes and are intriguing targets for drug discovery campaigns. Advancements in experimental and computational techniques are leading to a growth of data accessibility, and, with it, an increased need for the analysis of PPIs. In this respect, visualization tools are essential instruments to represent and analyze biomolecular interactions. In this chapter, we reviewed some of the available tools, highlighting their features, and describing their functions with practical information on their usage.

Inadequacy of nutrients and contaminants found in porridge-type complementary foods in Rwanda

Child malnutrition remains persistently high in Rwanda. Complementary foods play a key role in young child nutrition. This study explores the quality and safety of complementary food products available in the Rwandan market. Ten of the most consumed porridge-type complementary food products in Rwanda have been analysed. Mean values of macronutrient and micronutrient contents were compared against three international standards and evaluated against label claims. Mean mycotoxin, microbiological, and pesticide contamination were compared with maximum tolerable limits. Mean energy density (385 kcal/100 g) and total fat content (7.9 g/100 g) were lower than all three international benchmarks. The mean fibre content of 8.5 g/100 g was above the maximum recommended amount of Codex Alimentarius and more than double the amount claimed on labels. Mean levels of vitamin A (retinyl palmitate, 0.54 mg/100 g) and vitamin E (α-tocopherol, 3.7 mg/100 g) fell significantly short of all three standards, whereas calcium and zinc requirements were only partially met. Average iron content was 12.1 mg/100 g. The analysis revealed a mean aflatoxin contamination of 61 μg/kg, and high mold and yeast infestation. Escherichia coli and pesticide residues were found, whereas no heavy metals could be quantitated. Overall, complementary food products in Rwanda show inadequate nutrient contents and high aflatoxin and microbial contamination levels. Improved regulation and monitoring of both local and imported products are needed to improve the quality and safety of complementary foods in Rwanda.

Inadequacy of Nutrients, Contaminants, and Label Claims Found in Porridge-type Complementary Foods in Rwanda (P10-042-19)

Objectives

Child malnutrition remains persistently high in Rwanda. Complementary foods play a key role in young child nutrition. This study explores the quality and safety of complementary food products available in the Rwandan market.

Methods

Nine of the most consumed porridge-type complementary food products in Rwanda were analyzed. A total of 17 samples, including local brands and brands from Uganda and Kenya, as well as imports from Switzerland and France, were purchased in commercial retail outlets in the Kigali area and tested. Mean values of macronutrient and micronutrient contents were compared against three international standards and evaluated against label claims. Mean mycotoxin, microbiological, pesticide, and heavy metal contamination were compared to maximum tolerable limits.

Results

Mean energy density (385 kcal/100 g) and total fat content (7.9 g/100 g) were lower than all three international benchmarks. The mean fiber content of 8.5 g/100 g was above the maximum recommended amount of Codex Alimentarius and more than double the amount claimed on labels. Mean levels of vitamin A (retinyl palmitate, 0.54 mg/100 g) and vitamin E (α-tocopherol, 3.7 mg/100 g) fell significantly short of all three standards, whereas calcium and zinc requirements were only partially met. Average iron content was 12.1 mg/100 g. The analysis revealed a mean aflatoxin contamination of 61 μg/kg, and high mold and yeast infestation. E.coli and pesticide residues were found, whereas no heavy metals could be quantitated in the samples.

Conclusions

Overall, complementary food products in Rwanda show inadequate nutrient contents and high aflatoxin and microbial contamination levels. Adequately implemented and enforced quality and safety standards are required to ensure complementary foods contribute to young child growth and prevent foodborne illness in this particularly vulnerable population.

Funding Sources

Sight and Life Foundation.

Supporting Tables, Images and/or Graphs

The efficacy of hyaluronic acid in postextraction sockets of impacted third molars: A pilot study

OBJECTIVE

This study aims to evaluate the effectiveness of local hyaluronic acid (HA) administration to surgically remove impacted third molar sockets and measure pain, swelling, and trismus.

MATERIALS AND METHODS

The study included a total of 25 healthy patients aged 18-29 years with asymptomatic bilaterally impacted lower third molars. All cases have been performed under local anesthesia. In the study group, 0.8% HA (Gengigel®) was applied in the postextraction sockets of the right third molars and in the control group nothing was applied to the extraction sockets of the left third molars. Postoperative pain, trismus, and swelling were evaluated on the 1st, 3rd, and 7th postoperative days.

RESULTS

No difference was determined between groups in facial swelling and maximum mouth opening. However, the amount of pain significantly reduced in HA groups according to visual analog scale (P = 0.001).

CONCLUSION

The results of this study showed that HA can produce an analgesic action in postextraction sockets after surgical removal of impacted teeth and therefore it has a clinical benefit to reduce usage of nonsteroidal anti-inflammatory drugs after dentoalveolar surgery.

Influence of platform switching on bone-level alterations: a three-year randomized clinical trial

The concept of platform switching has been introduced to implant dentistry based on clinical observations of reduced peri-implant crestal bone loss. However, published data are controversial, and most studies are limited to 12 months. The aim of the present randomized clinical trial was to test the hypothesis that platform switching has a positive impact on crestal bone-level changes after 3 years. Two implants with a diameter of 4 mm were inserted crestally in the posterior mandible of 25 patients. The intraindividual allocation of platform switching (3.3-mm platform) and the standard implant (4-mm platform) was randomized. After 3 months of submerged healing, single-tooth crowns were cemented. Patients were followed up at short intervals for monitoring of healing and oral hygiene. Statistical analysis for the influence of time and platform type on bone levels employed the Brunner-Langer model. At 3 years, the mean radiographic peri-implant bone loss was 0.69 ± 0.43 mm (platform switching) and 0.74 ± 0.57 mm (standard platform). The mean intraindividual difference was 0.05 ± 0.58 mm (95% confidence interval: -0.19, 0.29). Crestal bone-level alteration depended on time (p < .001) but not on platform type (p = .363). The present randomized clinical trial could not confirm the hypothesis of a reduced peri-implant crestal bone loss, when implants had been restored according to the concept of platform switching.

Supramolecular hydrogel capsules based on PEG: a step toward degradable biomaterials with rational design

Supramolecular microgel capsules based on polyethylene glycol (PEG) are a promising class of soft particulate scaffolds with tailored properties. An approach to fabricate such particles with exquisite control by droplet-based microfluidics is presented. Linear PEG precursor polymers that carry bipyridine moieties on both chain termini are gelled by complexation to iron(II) ions. To investigate the biocompatibility of the microgels, living mammalian cells are encapsulated within them. The microgel elasticity is controlled by using PEG precursors of different molecular weights at different concentrations and the influence of these parameters on the cell viabilities, which can be optimized to exceed 90% is studied. Reversion of the supramolecular polymer cross-linking allows the microcapsules to be degraded at mild conditions with no effect on the viability of the encapsulated and released cells.

Numerical investigations of the loading behaviour of a prefabricated non-rigid bar system

The aim of this study has been to systematically evaluate the loading behaviour of a novel pre-fabricated chair-side SFI-Bar(®) bar system supported by two implants using finite element (FE) analysis. Two series of FE models were created of the bar placed on two idealised implants and embedded in idealised bone segments using CAD data. In the first series, the inter-implant distance varied from 10 to 26mm; the second series consisted of a bar with a fixed implant distance of 26mm and varying horizontal fitting inaccuracy from 0.0 to 0.3mm. The bar was loaded vertically at 500 N. In all simulations, the regions with the greatest amount of stress were concentrated on the connecting elements of the bar and the bar itself. A slight increase in stress was observed with decreasing inter-implant distance. With a non-zero fitting inaccuracy, no clear correlation was observed between the amount of play and the stress distribution in the system. For a perfect fit, an obvious increase in stress was found in the implant and strain in the implant bed. With respect to the excessive static loading performed in our simulations and the resulting loading behaviour, we conclude that the SFI-Bar is a system suitable for clinical application.

Aufbau und Erprobung eines neuartigen Meßsystems für die dentale Biomechanik – Meßprinzip und Beispielmessungen des Hexapod-Meß-Systems / Design and Testing of a Novel Measuring Set-up for Use in Dental Biomechanics – Measuring Principle and Exemplary Measurements with the Hexapod Measuring System

A novel measuring set-up based on a hexapod system for use in dental biomechanics is described. It was specially developed to measure force/deflection characteristics of different dental materials and devices. The functionability and suitability of the system for use in experimental biomechanics were investigated in two different studies. In a first study the micro mobility of prosthetic telescopic crowns prior to and after simulated wear was determined to investigate the influence of wear processes on the stability of the anchorage elements and thus of prostheses. This study investigated the ability of the setup to load a specimen with high forces or torques of up to 100 Newton. The second study looked at the force/deflection characteristics of orthodontic anchorage pins used in orthodontics to additionally stabilize the anchorage unit, for example during molar movement. In this study specimens were loaded with small forces of less than 10 Newton, as are typically used in orthodontics. Using the setup, the deflection behaviour of these devices under high and low loading was measured at a resolution of approximately one micrometer or one angular second.

Effects of GABA on circular smooth muscle spontaneous activities of rat distal colon

GABAergic regulation of intestinal motility through the modulation of non-adrenergic non-cholinergic (NANC) neurons remains poorly understood especially in rat colon where very few studies have been undertaken. Therefore, the effects of GABA on circular preparations of rat distal colon were investigated using classical organ bath chambers to record spontaneous mechanical activities (SMA). SMA was characterized by the occurrence of rhythmic phasic contractions (type-I) or by spontaneously occurring large contractions superimposed on small rhythmic contractions (type-II). In the presence of atropine and guanethidine (NANC conditions), these large contractions were inhibited by bicuculline, a GABA(A)-receptor antagonist as well as by TTX, L-NAME and apamin together, or L 732-138, a NK1-receptor antagonist. In NANC conditions, GABA induced a transient monophasic relaxation or a biphasic effect characterized by a relaxation followed by a tonic contraction in both type-I and -II preparations. Both the inhibitory and excitatory effects of GABA were blocked by TTX and L-NAME + apamin; the GABA-induced contraction was also sensitive to L 732-138. The responses to GABA were mimicked by the GABA(A)-receptor agonist, muscimol, whereas baclofen and CACA, respectively GABA(B) and GABA(C)-receptors agonists showed no effect. These results demonstrated that only GABA(A)-receptors seem to be involved in the regulation of SMA in rat distal colon in NANC conditions. Release of NANC inhibitory transmitter (NO and probably ATP) and NANC excitatory transmitter (maybe substance P) might be involved.

Herpes simplex virus type 1 DNase: functional analysis of the enzyme expressed by recombinant baculovirus

Herpes simplex virus type 1 DNase (HSV-1 DNase) was expressed in insect cells by recombinant baculovirus (NPVUL12) and purified by a combination of anionic exchanger chromatography and gel filtration. Two polypeptides of 85 and 75 kD, whose ratio varied during purification, were induced 24 h after infection. The 75-kD protein was isolated and shown to possess catalytic activity. Gel filtration analysis indicated that the active form of the enzyme at an ionic strength of I = 0.3 is a dimeric protein with an apparent molecular weight of 130,000. The recombinant enzyme exhibited the overall characteristics of the native enzyme such as 5'-3' exonuclease and endonuclease activities with a preferred degradation of DNA. In the absence of extraneously added Mg2+, the enzyme was capable of removing mononucleotides from 5'-end-labeled DNA, but not from RNA and 3'-end-labeled DNA. The peculiar mechanism of double-strand DNA degradation suggests a specific role of HSV-1 DNase in DNA recombination processes during viral replication.

Impact of prenatal care with reduced frequency of visits in a residency teaching program

OBJECTIVE

To determine if decreasing the number of prenatal visits for routine obstetric patients affects pregnancy outcome.

STUDY DESIGN

A historical control study was designed to include 734 deliveries from January 1 to December 31, 1991, in women who had prenatal care per American College of Obstetricians and Gynecologists Committee Opinion no. 79, January 1990, guidelines for uncomplicated obstetric care. A prospective study cohort of women with 711 deliveries from January 1 to December 31, 1994, underwent prenatal care with modified guidelines to include: first visit at 6-12 weeks to confirm dating and obtain initial laboratory data, second visit at 16-20 weeks to obtain maternal serum alpha-fetoprotein screening, third visit at 24-28 weeks for 28-week laboratory data, fourth visit at 32 weeks, fifth visit at 36 weeks, sixth visit at 38 weeks, seventh visit at 40 weeks and weekly thereafter. Pregnancy outcomes included estimated fetal weight, gestational age at delivery, preeclampsia, Apgar score at one and five minutes and delivery mode. Neonatal outcomes, including stillbirth rate, preterm delivery rate, intraventricular hemorrhage rate, bronchopulmonary dysplasia and neonatal mortality, were evaluated.

RESULTS

There were no statistically significant differences in perinatal or neonatal outcomes with decreased prenatal visits from an average of 12 per pregnancy to 8.

CONCLUSION

Prenatal visits can be decreased in a teaching hospital in women with uncomplicated pregnancies from the standard number, 12-14 visits, to an average of 7 or 8 per patient without adverse perinatal outcomes.

[Modulatory effects of polyamines and GABA on rat ileal motility in vitro]

AIM

The aim of our work was to determine the effects of polyamines and GABA on rat ileum motility in vitro.

METHODS

Longitudinal strips dissected from control ileum or ileum without myenteric plexus after benzalkonium chloride (BAC) treatment were placed in organ bath chambers.

RESULTS

Spermine significantly inhibited spontaneous activity and nerve stimulation-induced response. Inhibition of spontaneous activity was not altered by BAC treatment or tetrodotoxin but was antagonized by BAY K 8644, a L-type calcium channel agonist. Spermine inhibitory effect on nerve-stimulation induced response disappeared after BAC treatment. GABA enhanced the response induced by nerve stimulation but did not antagonize spermine effects; its action was inhibited in presence of atropine and was mimicked by baclofen, a GABAB agonist.

CONCLUSION

Polyamines and GABA can modulate rat ileum motility in vitro. GABA acted via neural GABAB receptors. We demonstrate for the first time that spermine exerts a dual action through different mechanisms on both smooth muscle cells and probably intramural neurons.

The ADP-ribosylation factor (ARF)-related GTPase ARF-related protein binds to the ARF-specific guanine nucleotide exchange factor cytohesin and inhibits the ARF-dependent activation of phospholipase D

ADP-ribosylation factor-related protein (ARP) is a membrane-associated GTPase with remote similarity to the family of ADP-ribosylation factors (ARF). In a yeast two-hybrid screen designed to identify proteins interacting with ARP, we isolated a partial cDNA of the ARF-specific guanine nucleotide exchange factor mSec7-1/cytohesin encoding its N terminus and most of the Sec7 domain (codons 1-200). ARP and ARP-Q79L (GTPase-negative ARP) exhibited a higher affinity to mSec7-1-(1-200) than ARP-T31N (nucleotide exchange-defective ARP) in the two-hybrid assay. Similarly, full-length [35S]mSec7-1/cytohesin was specifically adsorbed to glutathione-Sepharose loaded with glutathione S-transferase (GST)-ARP-Q79L, GST-ARP, or GST-ARP-T31N, the latter exhibiting the lowest binding affinity. Overexpression of ARP-Q79L, but not of ARP-T31N, in COS-7 cells reduced the fluorescence from co-expressed green fluorescent protein fused with mSec7-1/cytohesin or mSec7-2/ARNO in plasma membranes as detected by deconvolution microscopy. Recombinant ARP and ARP-Q79L, but not ARP-T31N, inhibited the phospholipase D (PLD) activity stimulated by mSec7-2/ARNO and ARF in a system of isolated membranes. Furthermore, transfection of HEK-293 cells with ARP or ARP-Q79L, but not ARP-T31N, inhibited the muscarinic acetylcholine receptor-3 induced PLD stimulation and translocation of ARF from cytosol to membranes. These data suggest that the GTP-bound form of ARP specifically binds mSec7-1/cytohesin, and that ARP may be involved in a pathway inhibiting the ARF-controlled activity of PLD.

1H MRS in acute traumatic brain injury

The objective of this study was to demonstrate 1H MR spectroscopy (MRS) changes in cerebral metabolites after acute head trauma. Twenty-five patients (12 children, 13 adults) were examined with quantitative 1H MRS after closed head injury. Clinical grade (Glasgow Coma Scale [GCS]) and outcome (Rancho Los Amigos Medical Center Outcome Score [ROS]) were correlated with quantitative neurochemical findings. N-acetylaspartate (NAA), a neuronal and axonal marker, was reduced (P < .03-.001). In children, a reduced NAA/creatine plus phosphocreatine (Cr) level and the presence of detectable lipid/lactate predicted bad outcome (sensitivity, 89%; specificity, 89%). The first MRS examination of all patients correlated with ROS versus NAA (r = .65, P < .0001). Although most patients showed MRS abnormalities, striking heterogeneity of 1H MRS characterized the individual patients. 1H MRS identifies multiple patterns of diffuse brain injury after blunt head trauma. There was a strong correlation between MRS and outcome. Future prospective studies will be needed to determine the clinical usefulness of MRS in predicting outcome from closed head injury.

[Clinical uses of proton magnetic resonance spectroscopy of the brain]

In spite of all the scientific advances of the past few years, proton magnetic resonance spectroscopy of the brain has not attained the status of a routine examination technique with clinically accepted indications. The method should be considered as an additional option to MR imaging for inherited and acquired encephalopathic changes as well as, in future, for localization diagnosis of epilepsies. A proton magnetic resonance spectroscopic investigation without a prior intensive clinical and imaging investigation is not useful. Above all, factors influencing metabolite distribution such as for example, serum osmolality must be known. Methodological prerequisites for the clinical application of proton resonance spectroscopy are, first of all, a high stability of the chosen technique as well as a sufficiently certain quantification of metabolites and the availability of a reference group. The use of short echo times is necessary for the quantification of glutamine and the osmolyte myo-inositol. Indications for individual cases in which clinical investigations and MR topography cannot provide sufficient certainty and spectroscopy can furnish additional information are, in addition to uses in neuropediatrics, the suspicion of Alzheimer's dementia, HIV encephalopathy in early manifestations, and unclarified depressions of consciousness accompanying liver cirrhosis.

In situ hybridization analysis of Girk2 expression in the developing central nervous system in normal and weaver mice

A mutation in the gene Girk2 that encodes an inwardly rectifying potassium channel is the genetic defect causing the behavioral and pathologic abnormalities of the weaver mutant mouse. Of the pathologic abnormalities, the best studied is the neuronal degeneration that occurs in the cerebellar cortex and in the midbrain dopaminergic neurons. A detailed characterization of the topographic and temporal expression of Girk2 is fundamental to elucidate the mechanisms underlying neurodegeneration in these mutant mice. In this study we utilized in situ hybridization to determine the expression of Girk2 mRNA during prenatal and postnatal development in the murine central nervous system (CNS). Girk2 expression was seen in multiple regions of embryonic CNS including the cerebellum and midbrain. During postnatal development, the highest expression was seen in the cerebellum, midbrain and hippocampus. However, since the developing cerebellum undergoes significant neuronal loss due to the degeneration of granule cell precursors, Girk2 mRNA expression in this area decreases progressively.

Proton magnetic resonance spectroscopy of the brain in symptomatic and asymptomatic patients with liver cirrhosis

BACKGROUND & AIMS

Hepatic encephalopathy (HE) is associated with typical changes of cerebral metabolite pattern observed by proton magnetic resonance (MR) spectroscopy consisting of a depletion of myo-inositol and an increase of glutamine. The aim of this study was to determine whether abnormalities in brain metabolism in neurologically asymptomatic patients with liver cirrhosis can be detected by spectroscopy.

METHODS

In a prospective study, 39 patients with liver cirrhosis were examined clinically according to standardized neuropsychological tests to define whether overt, subclinical, or no hepatic encephalopathy was present. All patients underwent proton MR spectroscopy at short echo times.

RESULTS

Spectroscopy allowed for the diagnosis of subclinical HE in 4 of 4 cases and of overt HE in 10 of 11 cases. In 24 cases of mere liver cirrhosis and normal neuropsychological testing, a typical metabolic pattern with a depletion of myo-inositol and an increased glutamine peak were found. A good correlation between the glutamine signal and the clinical grading was found.

CONCLUSIONS

Proton MR spectroscopy allows for the diagnosis of HE and subclinical HE, also shows the typical pathological metabolite pattern in patients with cirrhotic livers without subclinical HE, and might be more sensitive than neuropsychological testing. Glutamine could serve as a spectroscopic marker for the clinical state of the patients.

Identification of NF2 germ-line mutations and comparison with neurofibromatosis 2 phenotypes

Neurofibromatosis 2 (NF2) is an autosomal inherited disorder that predisposes carriers to nervous system tumors. To examine genotype-phenotype correlations in NF2, we performed mutation analyses and gadolinium-enhanced magnetic resonance imaging of the head and full spine in 59 unrelated NF2 patients. In patients with vestibular schwannomas (VSs) or identified NF2 mutations, the mild phenotype was defined as < 2 other intracranial tumors and < or = 4 spinal tumors, and the severe phenotype as either > or = 2 other intracranial tumors of > 4 spinal tumors. Nineteen mutations were found in 20 (34%) of the patients and were distributed in 12 of the 17 exons of the NF2 gene, including intron-exon boundaries. Seven mutations were frameshift, six were nonsense, four were splice site, two were missense, and one was a 3-bp in frame deletion. The nonsense mutations included one codon 57 and two codon 262 C-->T transition in CpG dinucleotides. The frameshift and nonsense NF2 mutations occurred primarily in patients with severe phenotypes. The two missense mutations occurred in patients with mild phenotypes, and three of the four splice site mutations occurred in families with both mild and severe phenotypes. Truncating NF2 mutations are usually associated with severe phenotypes, but the association of some mutations with mild and severe phenotypes indicates that NF2 expression is influenced by stochastic, epigenetic, or environmental factors.

HIV-related metabolic abnormalities in the brain: depiction with proton MR spectroscopy with short echo times

PURPOSE

To analyze brain metabolite changes in human immunodeficiency virus (HIV)-positive neurologically asymptomatic patients and patients with acquired immunodeficiency syndrome (AIDS) dementia complex (ADC).

MATERIALS AND METHODS

Twelve ADC patients, 11 HIV-positive asymptomatic patients, and 10 healthy control subjects underwent magnetic resonance (MR) imaging and proton MR spectroscopy with short echo times. Changes in N-acetyl aspartate (NAA), choline (Cho), myoinositol (MI), and creatine (Cr) were presented as ratios with Cr as the reference.

RESULTS

Statistically significant (P < .05) differences were noted. In ADC patients, all with MR findings of brain atrophy and diffuse white matter disease, NA/Cr decreased (white matter, -31.8%; gray matter, -22.3%), MI/Cr increased (white matter, +42.5%; gray matter, +51.8%), and Cho/Cr increased (white matter, +20.6%; gray matter, +51.7%) compared with healthy control subjects. In HIV-positive asymptomatic patients, NA/Cr decreased slightly (white matter, -6.9%; gray matter, -5.1%), MI/Cr increased slightly (white matter, +13.7%; gray matter, +10.7%), and Cho/Cr did not change.

CONCLUSION

ADC has a uniform pathologic metabolic pattern that affects NAA, MI, and Cho. Proton MR spectroscopy with short echo times helps detect early abnormalities in clinically asymptomatic patients.

Proton magnetic resonance spectroscopy studies on human brain myo-inositol in hypo-osmolarity and hepatic encephalopathy

BACKGROUND/AIMS

Recent in vivo studies using proton magnetic resonance (1H-MR) spectroscopy showed low levels of myo-inositol in the brain in hepatic encephalopathy; the pathogenetic relevance of this observation is unclear.

METHODS

Myo-inositol and glutamine levels in the brain were studied in vivo by 1H-MR spectroscopy in patients with hypo-osmolarity and hepatic encephalopathy.

RESULTS

A patient with severe plasma hypo-osmolarity (222 mOsm/L) had almost undetectable signals for myo-inositol and glutamine/glutamate in the brain. Both signals reappeared after normalization of plasma osmolarity, suggesting that both myo-inositol and glutamine were released as organic osmolytes from the brain. A decreased cerebral myo-inositol signal is also found in low-grade hepatic encephalopathy but is accompanied by an increased glutamine signal. Cirrhotics without hepatic encephalopathy have near-normal inositol signals, and patients with acquired immunodeficiency syndrome encephalopathy have increased inositol signals.

CONCLUSIONS

The 1H-MR spectroscopic myo-inositol signal in the human brain predominantly reflects an osmosensitive inositol pool. It is hypothesized that its depletion in latent hepatic encephalopathy points to a disturbance of cell volume homeostasis in the brain as an early pathogenetic event. This may partly be caused by a hyperammonemia-induced glutamine accumulation in the brain.

Reduction of the mortality rate in aged burn patients

The management of elderly burn patients is time consuming for both nursing staff and physicians, and therapy remains often challenging and controversial. In a retrospective study, we analysed the outcome of two periods with different treatment modalities. An increased number of nurses, a change in the local burn wound treatment, better documentation of wound status and general conditions, and last, but not least, of nutritional aid, enabled us to reduce the mortality rate in patients over 65 years of age.

Characterization of insulin-like growth factor binding to human granulosa cells obtained during in vitro fertilization

Insulin and IGF-I affect in vitro ovarian stromal and follicular cell function in several species. We previously characterized insulin receptors on human granulosa cells obtained from in vitro fertilization procedures but were unable to demonstrate specific binding of IGF-I. Following modification of the assay conditions, we now report specific, high affinity IGF-1 binding sites on human granulosa cells. Substitution of equimolar concentrations of sucrose for sodium chloride in the buffer solution increased binding of IGF but not insulin in equilibrium assays. Maximal specific IGF-I binding was 2.69 +/- 0.30%/10(5) cells (SEM, n = 9) with half-maximal inhibition of binding at 2 ng/ml IGF-I. Unlabeled insulin recognized the type I IGF receptor with low affinity. An IGF-I receptor monoclonal antibody (alpha IR-3) inhibited 125I-IGF-I but not 125I-insulin binding. Affinity crosslinking followed by SDS/PAGE under reducing conditions revealed IGF-I binding at a molecular weight compatible with the alpha subunit of the type I IGF receptor and with a pattern of inhibition by various ligands that paralleled the equilibrium binding assays. IGF-I receptors are present on freshly isolated human ovarian granulosa cells obtained following pharmacologic stimulation with gonadotrophin according to the protocols of in vitro fertilization. The biologic function of these receptors currently is being investigated.