Bacteriocins: mechanism of membrane insertion and pore formation.

Lactic acid bacteria produce several types of pore forming peptides. Class I bacteriocins are lantibiotics that contain (methyl)lanthionine residues that may form intramolecular thioether rings. These peptides generally have a broad spectrum of activity and form unstable pores.

Deficient motor control in children with tic disorder: evidence from transcranial magnetic stimulation.

Decreased motor inhibition was reported in adult patients with tic disorder (TD) using the technique of transcranial magnetic stimulation. Since tics usually begin during childhood, motor threshold, cortical silent period (CSP) and intracortical inhibition/facilitation were measured in 21 TD children and 25 healthy children aged 10-16 years. In TD children motor threshold was normal.

Complementary and overlapping selectivity of the two-peptide bacteriocins plantaricin EF and JK.

Plantaricin EF and JK are both two-peptide bacteriocins produced by Lactobacillus plantarum C11. The mechanism of plantaricin EF and JK action was studied on L. plantarum 965 cells.

Single-sweep analysis of event-related potentials by wavelet networks--methodological basis and clinical application.

Objective: Trial-to-trial variabilities in event-related potentials (ERP's), which are neglected by investigating averaged ERP's, can be important to establish group-specific effects in clinical studies. Single ERP responses have to be analyzed to quantify these variations. In order to overcome the disadvantages of existing single-sweep estimators, we have developed a new procedure based on wavelet networks (WN's) and applied this novel approach in a study concerning attention deficit hyperactivity disorder (ADHD) in children.

Persistently increased density of serotonin transporters in the frontal cortex of rats treated with fluoxetine during early juvenile life.

This experimental animal study was performed in order to assess possible long-term effects of the administration of the selective serotonin reuptake inhibitor fluoxetine (Prozac) during early periods of juvenile life on the developing central serotonergic and noradrenergic systems. Fluoxetine was administered via the drinking water (5 mg/kg/day) for a period of two weeks to very young (day 25) and somewhat older (day 50) rats. The effect of this treatment on the density of serotonin and noradrenaline transporters was measured by ligand-binding assays in various brain regions.

[Relationship between tics and compulsion].

In children and adolescents motor/vocal tics and obsessive-compulsive behavior are known to be closely related. Thereby, a continuum of symptoms ranging from single tics to a mixed picture of tics/rituals/obsessive-compulsive traits to clinically relevant obsessions and compulsions could be described. As neurobiological substrates dysfunctions in corresponding cortico-striato-thalamocortical circuits (sensorimotor circuit in tic symptomatology, orbitofrontal circuit in obsessive-compulsive behavior) were postulated.

A limited repertoire of mutations of the luteinizing hormone (LH) receptor gene in familial and sporadic patients with male LH-independent precocious puberty.

Herein, we report mutation analysis of the LH receptor gene in 17 males with LH-independent precocious puberty, of which 8 were familial and 9 had a negative family history. A total of 7 different mutations (all previously reported) were detected in 12 patients. Among 10 European familial male-limited precocious puberty (FMPP) patients who had a LH receptor gene mutation, none had the Asp578Gly mutation, which is responsible for the vast majority of cases in the U.

[Lithium salts in child and adolescent psychiatry].

Lithium is--besides neuroleptics--the drug of choice for the treatment of manic episodes. If the use of antidepressive drugs, during unipolar depressive illness, does not lead to a positive response, the additional administration of lithium is appropriate, even during a depressive episode. Lithium is also considered as the drug of choice for prophylactic treatment of bipolar affective disorders.

The lantibiotic nisin induces transmembrane movement of a fluorescent phospholipid.

Nisin is a pore-forming antimicrobial peptide. The capacity of nisin to induce transmembrane movement of a fluorescent phospholipid in lipid vesicles was investigated. Unilamellar phospholipid vesicles that contained a fluorescent phospholipid (1-acyl-2-(6-[(7-nitro-2-1, 3-benzoxadiazol-4-yl)amino]caproyl)-sn-glycero-3-phosphocholine) in the inner leaflet of the bilayer were used.

Plantaricin A is an amphiphilic alpha-helical bacteriocin-like pheromone which exerts antimicrobial and pheromone activities through different mechanisms.

Production of bacteriocins by lactic acid bacteria is in some cases regulated by a quorum sensing mechanism that involves a secreted bacteriocin-like peptide pheromone. In the case of Lactobacillus plantarum C11, this pheromone, the 26-mer plantaricin A (PlnA), has the interesting property of having both bacteriocin and pheromone activities. To gain insight into how PlnA functions as a pheromone and as a bacteriocin, the L- and D-enantiomers of an N-terminally truncated form of PlnA were synthesized (PlnA-22L and PlnA-22D; PlnA-22L has full biological activity).

Mechanistic properties of the two-component bacteriocin lactococcin G.

Lactococcin G is a bacteriocin whose activity depends on the complementary action of two peptides, termed alpha and beta. Biologically active, synthetic lactococcin G was used to study the mode of action on sensitive cells of Lactococcus lactis. The alpha and beta peptides can bind independently to the target cell surface, but activity requires the complementary peptide.

Pediatric Graves' disease: therapeutic options and experience with radioiodine at the University of Mississippi Medical Center.

Background: Pediatric Graves' disease can be life-threatening, and it adversely alters growth and development. Controversies concerning optimal therapy led us to review our 40 pediatric patients treated for Graves' disease from 1988 to 1996 to assess efficiency, efficacy, and safety of current therapy options.

Methods: Diagnosis of Graves' disease required clinical hyperthyroidism with supportive laboratory studies.

Role of transmembrane pH gradient and membrane binding in nisin pore formation.

Nisin is a cationic antimicrobial peptide that belongs to the group of lantibiotics. It is thought to form oligomeric pores in the target membrane by a mechanism that requires the transmembrane electrical potential delta psi and that involves local pertubation of the lipid bilayer structure. Here we show that nisin does not form exclusively voltage-dependent pores: even in the absence of a delta psi, nisin is able to dissipate the transmembrane pH gradient (delta pH) in sensitive Lactococcus lactis cells and proteoliposomes.

Tight connection between choline transport and phosphatidylcholine synthesis in MDCK cells.

In MDCK cells, choline uptake, the first step in the CDP-choline pathway for the biosynthesis of choline-containing phospholipids and osmolytes, occurs via both a transport system highly specific for choline and a non-specific pathway. The specific choline carrier is present at the apical domain of cells grown on dishes and is sodium-independent. Growing the cells on a permeant support results in the preferential localization of the specific choline carrier at the basolateral domain.

Mechanism of lantibiotic-induced pore-formation.

Nisin and other lantibiotics have a bacteriocidal effect against Gram-positive bacteria, and also inhibit the outgrowth of bacterial spores. The bacteriocidal effect appears to be due to the formation of pores in the bacterial membrane. In the absence of anionic membrane phospholipids, the lantibiotic nisin acts as an anion selective carrier.

Lactococcin G is a potassium ion-conducting, two-component bacteriocin.

Lactococcin G is a novel lactococcal bacteriocin whose activity depends on the complementary action of two peptides, termed alpha and beta. Peptide synthesis of the alpha and beta peptides yielded biologically active lactococcin G, which was used in mode-of-action studies on sensitive cells of Lactococcus lactis. Approximately equivalent amounts of both peptides were required for optimal bactericidal effect.

Lipid interaction of the 37-kDa and 58-kDa fragments of the Helicobacter pylori cytotoxin.

Helicobacter pylori cytotoxin vacA (95 kDa) causes a vacuolar degeneration of epithelial cells. There is evidence that this protein toxin acts inside cells, and hence has to cross a cell membrane. This cytotoxin is frequently obtained as two fragments of 58 kDa (p58) and 37 kDa (p37) and it is available only in minute amounts.

Decreased catalase activity but unchanged superoxide dismutase activity in brains of patients with dementia of Alzheimer type.

"Oxidative stress" may be of significance in the etiopathogenesis of dementia of Alzheimer type (DAT). Therefore, we measured activities of the enzymes superoxide dismutase (SOD) and catalase (CAT), which detoxicate reactive oxygen species. Enzyme activities were measured postmortem in basal ganglia, cortical, and limbic brain regions of patients with DAT and age-matched controls.

Rhinocerebral mucormycosis in IDDM. Sequential magnetic resonance imaging of long-term survival with intensive therapy.

Objective: To describe the clinical course and the utility of computerized tomography (CT) and magnetic resonance imaging (MRI) in the successful management of an often fatal fungal infection in a 12-year-old patient with insulin-dependent diabetes mellitus (IDDM).

Case: The patient was admitted to The University of Mississippi Medical Center (UMC) for the purpose of diabetic ketoacidosis (DKA) management and subsequent intensive therapy for mucormycosis according to nationally accepted standards of care. Strict diabetic control was instituted with frequent monitoring of blood glucose levels and interval assessment of HbA1c.

Cholesterol distribution in renal epithelial cells LLC-PK1 as determined by cholesterol oxidase: evidence that glutaraldehyde fixation masks plasma membrane cholesterol pools.

Treatment with cholesterol oxidases has shown that cholesterol is heterogeneously distributed in brush border membranes isolated from the apical domain of the renal and intestinal epithelial cells [Bloj, B., & Zilversmit, D. B.

Standard EEG and dyslexia in children--new evidence for specific correlates?

Contrary to the current assumption that there are no specific correlates of dyslexia in the standard clinical EEG, we have often noted a spontaneous "intermittent left parietal alpha desynchronization" (ILPAD) when visually evaluating the standard EEGs of children with delayed speech and language development and/or dyslexia. Visual evaluations of EEGs, as well as computer-assisted frequency analysis of three pairs of matched groups (healthy and hyperkinetic children with vs. without relatively "low levels" of verbal performance, as well as children with other child psychiatric disorders with vs.

Transport of choline by Madin-Darby canine kidney cells.

Choline is an essential precursor for the synthesis of phosphatidylcholine, the most abundant phospholipid classes in renal cells, as well as for the synthesis of the osmolyte glycerophosphorylcholine. The characteristics of choline uptake in the renal epithelial cell line MDCK were investigated. In the range of physiological concentrations, choline entered MDCK cells, grown as a monolayer on solid support, via a specific sodium-independent transport system (apparent Km = 43 microM, apparent Vmax = 284 pmol/mg protein per 5 min).

Cosegregation of missense mutations of the luteinizing hormone receptor gene with familial male-limited precocious puberty.

Familial male-limited precocious puberty is a male-limited autosomal dominant condition. It is characterized by increased testosterone synthesis in the absence of testicular stimulation by luteinizing hormone (LH). We hypothesised that an abnormal configuration of the LH receptor might autonomously activate G protein coupling, and thereby cause the overproduction of testosterone in this condition.